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000
FXUS63 KDTX 190814
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
314 AM EST FRI DEC 19 2014

.SHORT TERM...TODAY AND TONIGHT

THE 00Z DTX SHOWED A SATURATED 850 MB LAYER...WITH A TEMP/DEW PT OF
-10 C. FARTHER NORTH...A DRAMATIC DIFFERENCE...AS APX REVEALED AN
850 MB DEW PT DEPRESSION OF 31 C. AN UPPER WAVE SEEN OVER EASTERN
ONTARIO TRACKING INTO THE EASTERN GREAT LAKES TODAY WILL CONTINUE TO
HELP WITH THE DRY PUSH TO THE SOUTH...BUT CONFIDENCE IN CLEARING
DIMINISHES AS ONE HEADS SOUTH OF THE M-59 CORRIDOR...AS 00Z NAM
STILL INDICATING ENOUGH 950-925 MB MOISTURE/RH LINGERING...AS THE
LOW LEVEL FLOW WILL BE CALM TO VERY LIGHT. SURFACE
TROUGH/CONVERGENCE SEEN SINKING SOUTH AND EXITING LENAWEE AND MONROE
COUNTIES SHORTLY AFTER 12Z...AND THUS SHOULD END THE FREEZING
DRIZZLE THREAT AS THE DRIER AIR TAKES HOLD. NAM SOUNDINGS SHOWING
SHALLOW MOISTURE LAYER WITHIN THE 1-2 KFT LAYER THROUGH TONIGHT (I-
94 CORRIDOR AND POINTS SOUTH)....AS THE LOW LEVEL INVERSION
INCREASES/SHARPENS UP. CURRENT TRENDS/CLEARING LINE ARE MATCHED UP
FAIRLY WELL WITH THE NAM...AND WILL THUS MAINTAIN A GOOD DEAL OF
CLOUDS TOWARD THE OHIO BORDER. EVEN WITH SUNSHINE FARTHER NORTH
TODAY...SURFACE HIGH IN PLACE WILL LIMIT THE MIXING DEPTHS...AS
MID DECEMBER INSOLATION WILL PROBABLY BE ONLY GOOD FOR LOW/MID
30S...IN LINE WITH 925 MB FORECASTED TEMPS OF -4 TO -6 C. GUIDANCE
TEMPS FOR TONIGHT CALL FOR UPPER TEENS NORTH TO LOWER 20S SOUTH
DUE TO THE LINGERING CLOUDS.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY

UPPER LEVEL PATTERN WILL REMAIN QUASI-ZONAL THROUGH THE WEEKEND AS
UPPER TROUGHING OVER NEW ENGLAND SHIFT NORTHEAST AND THE BEGINNINGS
OF THE NEXT UPPER TROUGH OVER THE ROCKIES/PLAINS JUST GET UNDERWAY.
WHILE PRECIPITATION CHANCES WILL REMAIN MINIMAL THROUGH THE WEEKEND
AS HIGH PRESSURE EAST THROUGH THE OHIO VALLEY AND GREAT LAKES...THE
CLOUD FORECAST WILL REMAIN TRICKY AS A SERIES OF WEAK UPPER LEVEL
DISTURBANCES RACES THROUGH THE RELATIVELY FLAT UPPER LEVEL FLOW.
THIS SHOULD MAINTAIN A GENERAL PARTLY TO MOSTLY CLOUDY FORECAST.
TEMPERATURES REALLY WON/T CHANGE TOO MUCH...PERHAPS MODERATING A FEW
DEGREES WITH HIGHS RANGING IN THE LOWER/MID 30S AND LOWS IN THE MID
20S.

AFOREMENTIONED PLAINS TROUGHING BEGINS TO AMPLIFY SIGNIFICANTLY
EARLY NEXT WEEK AS A STEADY STREAM OF NORTHERN PACIFIC JET ENERGY
WORKS EAST/SOUTHEAST FROM THE PACIFIC NORTHWEST/BRITISH COLUMBIAN
COAST INTO THE MIDDLE OF THE CONUS. INITIALLY...THIS WILL LEAD TO AN
EXPANDING SHORTWAVE RIDGE INTO THE EASTERN CONUS...WHICH WILL BRING
A MORE NOTABLE MODERATION IN TEMPERATURES MONDAY AND TUESDAY AS
HIGHS CLIMB BACK TO 40 DEGREES OR BETTER. PRECIPITATION CHANCES WILL
STEADILY INCREASE DURING THIS TIME FRAME AS MOISTURE STREAMS INTO
AREA WITHIN EXPANDING SOUTHWEST FLOW REGIME IN ADVANCE OF THE
DEVELOPING STORM SYSTEM OVER THE PLAINS. OTHER THAN AN INITIAL MIX
OF LIGHT RAIN/SNOW MONDAY AS COLD AIR IS DISLODGED...EXPECT MAINLY
RAIN MONDAY NIGHT INTO TUESDAY AS PRECIPITATION CHANCES...IN
GENERAL...MARKEDLY INCREASE.

FROM THAT POINT FORWARD...THE FORECAST BECOMES EVER MORE DIFFICULT
TO PIN DOWN AS THE UPPER TROUGH TO THE WEST PIVOTS INTO AREA AS A
NEGATIVELY TILTED FEATURE. THIS SHOULD LEAD TO A GRADUAL TRANSITION
BACK TO A RAIN/SNOW MIX AND THEN SNOW AS COLDER AIR WORKS EAST INTO
AREA WITH THIS EXPANDING TROUGH. PRECIPITATION CHANCES WILL REMAIN
RATHER HIGH AS THIS TROUGH WORKS INTO THE AREA. TO COMPLICATE
MATTERS FURTHER...MEDIUM RANGE MODELS REMAIN SOMEWHAT SPLIT AS TO
HOW SIGNIFICANT A SOUTHERN STREAM SHORTWAVE WILL BE AS IT LIFTS INTO
THE DEVELOPING UPPER TROUGH OVER THE AREA. HOWEVER...GIVEN FACT THAT
00Z ECMWF/CANADIAN GEM NOAM BOTH DEVELOP A RATHER ROBUST STORM OVER
OR NEAR THE AREA BY WEDNESDAY AS THIS SOUTHERN ENERGY PHASES INTO
NORTHERN STREAM TROUGH...CONFIDENCE IS PERHAPS INCREASING SLIGHTLY
THAT A NOTEWORTHY STORM WILL WORK INTO/NEAR THE AREA BY MIDWEEK.
WHILE GFS DOES NOT SHARE THIS SOLUTION ATTM...AT LEAST HALF OF THE
ENSEMBLE MEMBERS DO TO A SIGNIFICANT DEGREE.

SUCH A SOLUTION WOULD BRING AN EXPANDING PRECIPITATION SHIELD INTO
THE AREA ON WEDNESDAY WITH A MIXTURE OF RAIN/SNOW CHANGING TO SNOW
WITH TIME AS THE SYSTEM INTENSIFIES AND LIFTS NORTH/NORTHEAST INTO
THE EASTERN GREAT LAKES/NORTHEAST CONUS INTO WEDNESDAY NIGHT. WHILE
THE ECMWF/NOAM CMC DO HAVE RATHER OMINOUS REPRESENTATIONS OF THIS
POTENTIAL WINTER STORM...A NUMBER OF SCENARIOS STILL REMAIN QUITE
PLAUSIBLE...RANGING FOR MINIMAL SOUTHERN DEVELOPMENT OF THIS
TROUGH TO THE SOUTHERN ENERGY SHIFTING EAST OF THE APPALACHIANS AND
THEN LIFTING UP/NEAR THE EASTERN SEABOARD. GIVEN THE UNCERTAINTY
OF A DAY 6 FORECAST...WILL NOT ADJUST FORECAST TOO ANY GREAT DEGREE
WITH THIS FORECAST PACKAGE. SUFFICE IT TO SAY THAT THE MIDWEEK
PERIOD NEXT WEEK DOES APPEAR TO BE RATHER ACTIVE FOR THE AREA AS
COMPARED TO THE CURRENT WEATHER REGIME.

&&

.MARINE...

SURFACE HIGH PRESSURE IS FORECASTED TO BUILD INTO THE AREA DURING
THE DAY TODAY AND THEN DRIFT EAST ACROSS THE CENTRAL AND EASTERN
GREAT LAKES OVER THE WEEKEND. THIS WILL LEAD TO EXCEEDINGLY CALM
CONDITIONS FOR THIS TIME OF YEAR...AT LEAST INTO MUCH OF SUNDAY.
SOUTHERLY WINDS WILL THEN BEGIN TO INCREASE ON THE BACKSIDE OF THIS
HIGH SUNDAY INTO MONDAY. EVEN SO...RATHER AGREEABLE MARINE
CONDITIONS ARE EXPECTED INTO EARLY NEXT WEEK AS WINDS/WAVES ONLY
INCREASE MARGINALLY WITHIN THIS DEVELOPING SOUTH/SOUTHEAST FLOW.

&&

.AVIATION...ISSUED 1154 PM EST THU DEC 18 2014

//DISCUSSION...

WEAK SURFACE TROUGHING SUSTAINING A LIGHT MIX OF FREEZING DRIZZLE
WITH SOME SNOWFLAKES EARLY THIS MORNING. THIS PRECIPITATION IS
EXPECTED TO DIMINISH IN COVERAGE THROUGH THE EARLY MORNING HOURS.
THE EXISTING DEEP PLUME OF LOW LEVEL MOISTURE AND ASSOCIATED MVFR
CEILING WILL BE SLOWER TO DECREASE. UPSTREAM SATELLITE TRENDS
WOULD BRING THE EDGE OF THE CLEARING LINE NOW MOVING THROUGH
NORTHERN LOWER INTO MBS BY DAYBREAK. MOISTURE MAY BE SLOWER TO
ERODE TOWARD THE SOUTH AND WILL MAINTAIN A MORE GRADUAL CLEARING
INTO THE REMAINDER OF SE MICHIGAN ON FRIDAY. A LIGHT WIND FIELD
THROUGH THE PERIOD.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW THROUGH 09-10Z.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING...LOW CONFIDENCE INTO THE AFTERNOON.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW EARLY THIS MORNING.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

SHORT TERM...SF
LONG TERM....DG
MARINE.......DG
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 190814
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
314 AM EST FRI DEC 19 2014

.SHORT TERM...TODAY AND TONIGHT

THE 00Z DTX SHOWED A SATURATED 850 MB LAYER...WITH A TEMP/DEW PT OF
-10 C. FARTHER NORTH...A DRAMATIC DIFFERENCE...AS APX REVEALED AN
850 MB DEW PT DEPRESSION OF 31 C. AN UPPER WAVE SEEN OVER EASTERN
ONTARIO TRACKING INTO THE EASTERN GREAT LAKES TODAY WILL CONTINUE TO
HELP WITH THE DRY PUSH TO THE SOUTH...BUT CONFIDENCE IN CLEARING
DIMINISHES AS ONE HEADS SOUTH OF THE M-59 CORRIDOR...AS 00Z NAM
STILL INDICATING ENOUGH 950-925 MB MOISTURE/RH LINGERING...AS THE
LOW LEVEL FLOW WILL BE CALM TO VERY LIGHT. SURFACE
TROUGH/CONVERGENCE SEEN SINKING SOUTH AND EXITING LENAWEE AND MONROE
COUNTIES SHORTLY AFTER 12Z...AND THUS SHOULD END THE FREEZING
DRIZZLE THREAT AS THE DRIER AIR TAKES HOLD. NAM SOUNDINGS SHOWING
SHALLOW MOISTURE LAYER WITHIN THE 1-2 KFT LAYER THROUGH TONIGHT (I-
94 CORRIDOR AND POINTS SOUTH)....AS THE LOW LEVEL INVERSION
INCREASES/SHARPENS UP. CURRENT TRENDS/CLEARING LINE ARE MATCHED UP
FAIRLY WELL WITH THE NAM...AND WILL THUS MAINTAIN A GOOD DEAL OF
CLOUDS TOWARD THE OHIO BORDER. EVEN WITH SUNSHINE FARTHER NORTH
TODAY...SURFACE HIGH IN PLACE WILL LIMIT THE MIXING DEPTHS...AS
MID DECEMBER INSOLATION WILL PROBABLY BE ONLY GOOD FOR LOW/MID
30S...IN LINE WITH 925 MB FORECASTED TEMPS OF -4 TO -6 C. GUIDANCE
TEMPS FOR TONIGHT CALL FOR UPPER TEENS NORTH TO LOWER 20S SOUTH
DUE TO THE LINGERING CLOUDS.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY

UPPER LEVEL PATTERN WILL REMAIN QUASI-ZONAL THROUGH THE WEEKEND AS
UPPER TROUGHING OVER NEW ENGLAND SHIFT NORTHEAST AND THE BEGINNINGS
OF THE NEXT UPPER TROUGH OVER THE ROCKIES/PLAINS JUST GET UNDERWAY.
WHILE PRECIPITATION CHANCES WILL REMAIN MINIMAL THROUGH THE WEEKEND
AS HIGH PRESSURE EAST THROUGH THE OHIO VALLEY AND GREAT LAKES...THE
CLOUD FORECAST WILL REMAIN TRICKY AS A SERIES OF WEAK UPPER LEVEL
DISTURBANCES RACES THROUGH THE RELATIVELY FLAT UPPER LEVEL FLOW.
THIS SHOULD MAINTAIN A GENERAL PARTLY TO MOSTLY CLOUDY FORECAST.
TEMPERATURES REALLY WON/T CHANGE TOO MUCH...PERHAPS MODERATING A FEW
DEGREES WITH HIGHS RANGING IN THE LOWER/MID 30S AND LOWS IN THE MID
20S.

AFOREMENTIONED PLAINS TROUGHING BEGINS TO AMPLIFY SIGNIFICANTLY
EARLY NEXT WEEK AS A STEADY STREAM OF NORTHERN PACIFIC JET ENERGY
WORKS EAST/SOUTHEAST FROM THE PACIFIC NORTHWEST/BRITISH COLUMBIAN
COAST INTO THE MIDDLE OF THE CONUS. INITIALLY...THIS WILL LEAD TO AN
EXPANDING SHORTWAVE RIDGE INTO THE EASTERN CONUS...WHICH WILL BRING
A MORE NOTABLE MODERATION IN TEMPERATURES MONDAY AND TUESDAY AS
HIGHS CLIMB BACK TO 40 DEGREES OR BETTER. PRECIPITATION CHANCES WILL
STEADILY INCREASE DURING THIS TIME FRAME AS MOISTURE STREAMS INTO
AREA WITHIN EXPANDING SOUTHWEST FLOW REGIME IN ADVANCE OF THE
DEVELOPING STORM SYSTEM OVER THE PLAINS. OTHER THAN AN INITIAL MIX
OF LIGHT RAIN/SNOW MONDAY AS COLD AIR IS DISLODGED...EXPECT MAINLY
RAIN MONDAY NIGHT INTO TUESDAY AS PRECIPITATION CHANCES...IN
GENERAL...MARKEDLY INCREASE.

FROM THAT POINT FORWARD...THE FORECAST BECOMES EVER MORE DIFFICULT
TO PIN DOWN AS THE UPPER TROUGH TO THE WEST PIVOTS INTO AREA AS A
NEGATIVELY TILTED FEATURE. THIS SHOULD LEAD TO A GRADUAL TRANSITION
BACK TO A RAIN/SNOW MIX AND THEN SNOW AS COLDER AIR WORKS EAST INTO
AREA WITH THIS EXPANDING TROUGH. PRECIPITATION CHANCES WILL REMAIN
RATHER HIGH AS THIS TROUGH WORKS INTO THE AREA. TO COMPLICATE
MATTERS FURTHER...MEDIUM RANGE MODELS REMAIN SOMEWHAT SPLIT AS TO
HOW SIGNIFICANT A SOUTHERN STREAM SHORTWAVE WILL BE AS IT LIFTS INTO
THE DEVELOPING UPPER TROUGH OVER THE AREA. HOWEVER...GIVEN FACT THAT
00Z ECMWF/CANADIAN GEM NOAM BOTH DEVELOP A RATHER ROBUST STORM OVER
OR NEAR THE AREA BY WEDNESDAY AS THIS SOUTHERN ENERGY PHASES INTO
NORTHERN STREAM TROUGH...CONFIDENCE IS PERHAPS INCREASING SLIGHTLY
THAT A NOTEWORTHY STORM WILL WORK INTO/NEAR THE AREA BY MIDWEEK.
WHILE GFS DOES NOT SHARE THIS SOLUTION ATTM...AT LEAST HALF OF THE
ENSEMBLE MEMBERS DO TO A SIGNIFICANT DEGREE.

SUCH A SOLUTION WOULD BRING AN EXPANDING PRECIPITATION SHIELD INTO
THE AREA ON WEDNESDAY WITH A MIXTURE OF RAIN/SNOW CHANGING TO SNOW
WITH TIME AS THE SYSTEM INTENSIFIES AND LIFTS NORTH/NORTHEAST INTO
THE EASTERN GREAT LAKES/NORTHEAST CONUS INTO WEDNESDAY NIGHT. WHILE
THE ECMWF/NOAM CMC DO HAVE RATHER OMINOUS REPRESENTATIONS OF THIS
POTENTIAL WINTER STORM...A NUMBER OF SCENARIOS STILL REMAIN QUITE
PLAUSIBLE...RANGING FOR MINIMAL SOUTHERN DEVELOPMENT OF THIS
TROUGH TO THE SOUTHERN ENERGY SHIFTING EAST OF THE APPALACHIANS AND
THEN LIFTING UP/NEAR THE EASTERN SEABOARD. GIVEN THE UNCERTAINTY
OF A DAY 6 FORECAST...WILL NOT ADJUST FORECAST TOO ANY GREAT DEGREE
WITH THIS FORECAST PACKAGE. SUFFICE IT TO SAY THAT THE MIDWEEK
PERIOD NEXT WEEK DOES APPEAR TO BE RATHER ACTIVE FOR THE AREA AS
COMPARED TO THE CURRENT WEATHER REGIME.

&&

.MARINE...

SURFACE HIGH PRESSURE IS FORECASTED TO BUILD INTO THE AREA DURING
THE DAY TODAY AND THEN DRIFT EAST ACROSS THE CENTRAL AND EASTERN
GREAT LAKES OVER THE WEEKEND. THIS WILL LEAD TO EXCEEDINGLY CALM
CONDITIONS FOR THIS TIME OF YEAR...AT LEAST INTO MUCH OF SUNDAY.
SOUTHERLY WINDS WILL THEN BEGIN TO INCREASE ON THE BACKSIDE OF THIS
HIGH SUNDAY INTO MONDAY. EVEN SO...RATHER AGREEABLE MARINE
CONDITIONS ARE EXPECTED INTO EARLY NEXT WEEK AS WINDS/WAVES ONLY
INCREASE MARGINALLY WITHIN THIS DEVELOPING SOUTH/SOUTHEAST FLOW.

&&

.AVIATION...ISSUED 1154 PM EST THU DEC 18 2014

//DISCUSSION...

WEAK SURFACE TROUGHING SUSTAINING A LIGHT MIX OF FREEZING DRIZZLE
WITH SOME SNOWFLAKES EARLY THIS MORNING. THIS PRECIPITATION IS
EXPECTED TO DIMINISH IN COVERAGE THROUGH THE EARLY MORNING HOURS.
THE EXISTING DEEP PLUME OF LOW LEVEL MOISTURE AND ASSOCIATED MVFR
CEILING WILL BE SLOWER TO DECREASE. UPSTREAM SATELLITE TRENDS
WOULD BRING THE EDGE OF THE CLEARING LINE NOW MOVING THROUGH
NORTHERN LOWER INTO MBS BY DAYBREAK. MOISTURE MAY BE SLOWER TO
ERODE TOWARD THE SOUTH AND WILL MAINTAIN A MORE GRADUAL CLEARING
INTO THE REMAINDER OF SE MICHIGAN ON FRIDAY. A LIGHT WIND FIELD
THROUGH THE PERIOD.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW THROUGH 09-10Z.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING...LOW CONFIDENCE INTO THE AFTERNOON.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW EARLY THIS MORNING.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

SHORT TERM...SF
LONG TERM....DG
MARINE.......DG
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 190814
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
314 AM EST FRI DEC 19 2014

.SHORT TERM...TODAY AND TONIGHT

THE 00Z DTX SHOWED A SATURATED 850 MB LAYER...WITH A TEMP/DEW PT OF
-10 C. FARTHER NORTH...A DRAMATIC DIFFERENCE...AS APX REVEALED AN
850 MB DEW PT DEPRESSION OF 31 C. AN UPPER WAVE SEEN OVER EASTERN
ONTARIO TRACKING INTO THE EASTERN GREAT LAKES TODAY WILL CONTINUE TO
HELP WITH THE DRY PUSH TO THE SOUTH...BUT CONFIDENCE IN CLEARING
DIMINISHES AS ONE HEADS SOUTH OF THE M-59 CORRIDOR...AS 00Z NAM
STILL INDICATING ENOUGH 950-925 MB MOISTURE/RH LINGERING...AS THE
LOW LEVEL FLOW WILL BE CALM TO VERY LIGHT. SURFACE
TROUGH/CONVERGENCE SEEN SINKING SOUTH AND EXITING LENAWEE AND MONROE
COUNTIES SHORTLY AFTER 12Z...AND THUS SHOULD END THE FREEZING
DRIZZLE THREAT AS THE DRIER AIR TAKES HOLD. NAM SOUNDINGS SHOWING
SHALLOW MOISTURE LAYER WITHIN THE 1-2 KFT LAYER THROUGH TONIGHT (I-
94 CORRIDOR AND POINTS SOUTH)....AS THE LOW LEVEL INVERSION
INCREASES/SHARPENS UP. CURRENT TRENDS/CLEARING LINE ARE MATCHED UP
FAIRLY WELL WITH THE NAM...AND WILL THUS MAINTAIN A GOOD DEAL OF
CLOUDS TOWARD THE OHIO BORDER. EVEN WITH SUNSHINE FARTHER NORTH
TODAY...SURFACE HIGH IN PLACE WILL LIMIT THE MIXING DEPTHS...AS
MID DECEMBER INSOLATION WILL PROBABLY BE ONLY GOOD FOR LOW/MID
30S...IN LINE WITH 925 MB FORECASTED TEMPS OF -4 TO -6 C. GUIDANCE
TEMPS FOR TONIGHT CALL FOR UPPER TEENS NORTH TO LOWER 20S SOUTH
DUE TO THE LINGERING CLOUDS.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY

UPPER LEVEL PATTERN WILL REMAIN QUASI-ZONAL THROUGH THE WEEKEND AS
UPPER TROUGHING OVER NEW ENGLAND SHIFT NORTHEAST AND THE BEGINNINGS
OF THE NEXT UPPER TROUGH OVER THE ROCKIES/PLAINS JUST GET UNDERWAY.
WHILE PRECIPITATION CHANCES WILL REMAIN MINIMAL THROUGH THE WEEKEND
AS HIGH PRESSURE EAST THROUGH THE OHIO VALLEY AND GREAT LAKES...THE
CLOUD FORECAST WILL REMAIN TRICKY AS A SERIES OF WEAK UPPER LEVEL
DISTURBANCES RACES THROUGH THE RELATIVELY FLAT UPPER LEVEL FLOW.
THIS SHOULD MAINTAIN A GENERAL PARTLY TO MOSTLY CLOUDY FORECAST.
TEMPERATURES REALLY WON/T CHANGE TOO MUCH...PERHAPS MODERATING A FEW
DEGREES WITH HIGHS RANGING IN THE LOWER/MID 30S AND LOWS IN THE MID
20S.

AFOREMENTIONED PLAINS TROUGHING BEGINS TO AMPLIFY SIGNIFICANTLY
EARLY NEXT WEEK AS A STEADY STREAM OF NORTHERN PACIFIC JET ENERGY
WORKS EAST/SOUTHEAST FROM THE PACIFIC NORTHWEST/BRITISH COLUMBIAN
COAST INTO THE MIDDLE OF THE CONUS. INITIALLY...THIS WILL LEAD TO AN
EXPANDING SHORTWAVE RIDGE INTO THE EASTERN CONUS...WHICH WILL BRING
A MORE NOTABLE MODERATION IN TEMPERATURES MONDAY AND TUESDAY AS
HIGHS CLIMB BACK TO 40 DEGREES OR BETTER. PRECIPITATION CHANCES WILL
STEADILY INCREASE DURING THIS TIME FRAME AS MOISTURE STREAMS INTO
AREA WITHIN EXPANDING SOUTHWEST FLOW REGIME IN ADVANCE OF THE
DEVELOPING STORM SYSTEM OVER THE PLAINS. OTHER THAN AN INITIAL MIX
OF LIGHT RAIN/SNOW MONDAY AS COLD AIR IS DISLODGED...EXPECT MAINLY
RAIN MONDAY NIGHT INTO TUESDAY AS PRECIPITATION CHANCES...IN
GENERAL...MARKEDLY INCREASE.

FROM THAT POINT FORWARD...THE FORECAST BECOMES EVER MORE DIFFICULT
TO PIN DOWN AS THE UPPER TROUGH TO THE WEST PIVOTS INTO AREA AS A
NEGATIVELY TILTED FEATURE. THIS SHOULD LEAD TO A GRADUAL TRANSITION
BACK TO A RAIN/SNOW MIX AND THEN SNOW AS COLDER AIR WORKS EAST INTO
AREA WITH THIS EXPANDING TROUGH. PRECIPITATION CHANCES WILL REMAIN
RATHER HIGH AS THIS TROUGH WORKS INTO THE AREA. TO COMPLICATE
MATTERS FURTHER...MEDIUM RANGE MODELS REMAIN SOMEWHAT SPLIT AS TO
HOW SIGNIFICANT A SOUTHERN STREAM SHORTWAVE WILL BE AS IT LIFTS INTO
THE DEVELOPING UPPER TROUGH OVER THE AREA. HOWEVER...GIVEN FACT THAT
00Z ECMWF/CANADIAN GEM NOAM BOTH DEVELOP A RATHER ROBUST STORM OVER
OR NEAR THE AREA BY WEDNESDAY AS THIS SOUTHERN ENERGY PHASES INTO
NORTHERN STREAM TROUGH...CONFIDENCE IS PERHAPS INCREASING SLIGHTLY
THAT A NOTEWORTHY STORM WILL WORK INTO/NEAR THE AREA BY MIDWEEK.
WHILE GFS DOES NOT SHARE THIS SOLUTION ATTM...AT LEAST HALF OF THE
ENSEMBLE MEMBERS DO TO A SIGNIFICANT DEGREE.

SUCH A SOLUTION WOULD BRING AN EXPANDING PRECIPITATION SHIELD INTO
THE AREA ON WEDNESDAY WITH A MIXTURE OF RAIN/SNOW CHANGING TO SNOW
WITH TIME AS THE SYSTEM INTENSIFIES AND LIFTS NORTH/NORTHEAST INTO
THE EASTERN GREAT LAKES/NORTHEAST CONUS INTO WEDNESDAY NIGHT. WHILE
THE ECMWF/NOAM CMC DO HAVE RATHER OMINOUS REPRESENTATIONS OF THIS
POTENTIAL WINTER STORM...A NUMBER OF SCENARIOS STILL REMAIN QUITE
PLAUSIBLE...RANGING FOR MINIMAL SOUTHERN DEVELOPMENT OF THIS
TROUGH TO THE SOUTHERN ENERGY SHIFTING EAST OF THE APPALACHIANS AND
THEN LIFTING UP/NEAR THE EASTERN SEABOARD. GIVEN THE UNCERTAINTY
OF A DAY 6 FORECAST...WILL NOT ADJUST FORECAST TOO ANY GREAT DEGREE
WITH THIS FORECAST PACKAGE. SUFFICE IT TO SAY THAT THE MIDWEEK
PERIOD NEXT WEEK DOES APPEAR TO BE RATHER ACTIVE FOR THE AREA AS
COMPARED TO THE CURRENT WEATHER REGIME.

&&

.MARINE...

SURFACE HIGH PRESSURE IS FORECASTED TO BUILD INTO THE AREA DURING
THE DAY TODAY AND THEN DRIFT EAST ACROSS THE CENTRAL AND EASTERN
GREAT LAKES OVER THE WEEKEND. THIS WILL LEAD TO EXCEEDINGLY CALM
CONDITIONS FOR THIS TIME OF YEAR...AT LEAST INTO MUCH OF SUNDAY.
SOUTHERLY WINDS WILL THEN BEGIN TO INCREASE ON THE BACKSIDE OF THIS
HIGH SUNDAY INTO MONDAY. EVEN SO...RATHER AGREEABLE MARINE
CONDITIONS ARE EXPECTED INTO EARLY NEXT WEEK AS WINDS/WAVES ONLY
INCREASE MARGINALLY WITHIN THIS DEVELOPING SOUTH/SOUTHEAST FLOW.

&&

.AVIATION...ISSUED 1154 PM EST THU DEC 18 2014

//DISCUSSION...

WEAK SURFACE TROUGHING SUSTAINING A LIGHT MIX OF FREEZING DRIZZLE
WITH SOME SNOWFLAKES EARLY THIS MORNING. THIS PRECIPITATION IS
EXPECTED TO DIMINISH IN COVERAGE THROUGH THE EARLY MORNING HOURS.
THE EXISTING DEEP PLUME OF LOW LEVEL MOISTURE AND ASSOCIATED MVFR
CEILING WILL BE SLOWER TO DECREASE. UPSTREAM SATELLITE TRENDS
WOULD BRING THE EDGE OF THE CLEARING LINE NOW MOVING THROUGH
NORTHERN LOWER INTO MBS BY DAYBREAK. MOISTURE MAY BE SLOWER TO
ERODE TOWARD THE SOUTH AND WILL MAINTAIN A MORE GRADUAL CLEARING
INTO THE REMAINDER OF SE MICHIGAN ON FRIDAY. A LIGHT WIND FIELD
THROUGH THE PERIOD.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW THROUGH 09-10Z.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING...LOW CONFIDENCE INTO THE AFTERNOON.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW EARLY THIS MORNING.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

SHORT TERM...SF
LONG TERM....DG
MARINE.......DG
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 190814
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
314 AM EST FRI DEC 19 2014

.SHORT TERM...TODAY AND TONIGHT

THE 00Z DTX SHOWED A SATURATED 850 MB LAYER...WITH A TEMP/DEW PT OF
-10 C. FARTHER NORTH...A DRAMATIC DIFFERENCE...AS APX REVEALED AN
850 MB DEW PT DEPRESSION OF 31 C. AN UPPER WAVE SEEN OVER EASTERN
ONTARIO TRACKING INTO THE EASTERN GREAT LAKES TODAY WILL CONTINUE TO
HELP WITH THE DRY PUSH TO THE SOUTH...BUT CONFIDENCE IN CLEARING
DIMINISHES AS ONE HEADS SOUTH OF THE M-59 CORRIDOR...AS 00Z NAM
STILL INDICATING ENOUGH 950-925 MB MOISTURE/RH LINGERING...AS THE
LOW LEVEL FLOW WILL BE CALM TO VERY LIGHT. SURFACE
TROUGH/CONVERGENCE SEEN SINKING SOUTH AND EXITING LENAWEE AND MONROE
COUNTIES SHORTLY AFTER 12Z...AND THUS SHOULD END THE FREEZING
DRIZZLE THREAT AS THE DRIER AIR TAKES HOLD. NAM SOUNDINGS SHOWING
SHALLOW MOISTURE LAYER WITHIN THE 1-2 KFT LAYER THROUGH TONIGHT (I-
94 CORRIDOR AND POINTS SOUTH)....AS THE LOW LEVEL INVERSION
INCREASES/SHARPENS UP. CURRENT TRENDS/CLEARING LINE ARE MATCHED UP
FAIRLY WELL WITH THE NAM...AND WILL THUS MAINTAIN A GOOD DEAL OF
CLOUDS TOWARD THE OHIO BORDER. EVEN WITH SUNSHINE FARTHER NORTH
TODAY...SURFACE HIGH IN PLACE WILL LIMIT THE MIXING DEPTHS...AS
MID DECEMBER INSOLATION WILL PROBABLY BE ONLY GOOD FOR LOW/MID
30S...IN LINE WITH 925 MB FORECASTED TEMPS OF -4 TO -6 C. GUIDANCE
TEMPS FOR TONIGHT CALL FOR UPPER TEENS NORTH TO LOWER 20S SOUTH
DUE TO THE LINGERING CLOUDS.

&&

.LONG TERM...SATURDAY THROUGH THURSDAY

UPPER LEVEL PATTERN WILL REMAIN QUASI-ZONAL THROUGH THE WEEKEND AS
UPPER TROUGHING OVER NEW ENGLAND SHIFT NORTHEAST AND THE BEGINNINGS
OF THE NEXT UPPER TROUGH OVER THE ROCKIES/PLAINS JUST GET UNDERWAY.
WHILE PRECIPITATION CHANCES WILL REMAIN MINIMAL THROUGH THE WEEKEND
AS HIGH PRESSURE EAST THROUGH THE OHIO VALLEY AND GREAT LAKES...THE
CLOUD FORECAST WILL REMAIN TRICKY AS A SERIES OF WEAK UPPER LEVEL
DISTURBANCES RACES THROUGH THE RELATIVELY FLAT UPPER LEVEL FLOW.
THIS SHOULD MAINTAIN A GENERAL PARTLY TO MOSTLY CLOUDY FORECAST.
TEMPERATURES REALLY WON/T CHANGE TOO MUCH...PERHAPS MODERATING A FEW
DEGREES WITH HIGHS RANGING IN THE LOWER/MID 30S AND LOWS IN THE MID
20S.

AFOREMENTIONED PLAINS TROUGHING BEGINS TO AMPLIFY SIGNIFICANTLY
EARLY NEXT WEEK AS A STEADY STREAM OF NORTHERN PACIFIC JET ENERGY
WORKS EAST/SOUTHEAST FROM THE PACIFIC NORTHWEST/BRITISH COLUMBIAN
COAST INTO THE MIDDLE OF THE CONUS. INITIALLY...THIS WILL LEAD TO AN
EXPANDING SHORTWAVE RIDGE INTO THE EASTERN CONUS...WHICH WILL BRING
A MORE NOTABLE MODERATION IN TEMPERATURES MONDAY AND TUESDAY AS
HIGHS CLIMB BACK TO 40 DEGREES OR BETTER. PRECIPITATION CHANCES WILL
STEADILY INCREASE DURING THIS TIME FRAME AS MOISTURE STREAMS INTO
AREA WITHIN EXPANDING SOUTHWEST FLOW REGIME IN ADVANCE OF THE
DEVELOPING STORM SYSTEM OVER THE PLAINS. OTHER THAN AN INITIAL MIX
OF LIGHT RAIN/SNOW MONDAY AS COLD AIR IS DISLODGED...EXPECT MAINLY
RAIN MONDAY NIGHT INTO TUESDAY AS PRECIPITATION CHANCES...IN
GENERAL...MARKEDLY INCREASE.

FROM THAT POINT FORWARD...THE FORECAST BECOMES EVER MORE DIFFICULT
TO PIN DOWN AS THE UPPER TROUGH TO THE WEST PIVOTS INTO AREA AS A
NEGATIVELY TILTED FEATURE. THIS SHOULD LEAD TO A GRADUAL TRANSITION
BACK TO A RAIN/SNOW MIX AND THEN SNOW AS COLDER AIR WORKS EAST INTO
AREA WITH THIS EXPANDING TROUGH. PRECIPITATION CHANCES WILL REMAIN
RATHER HIGH AS THIS TROUGH WORKS INTO THE AREA. TO COMPLICATE
MATTERS FURTHER...MEDIUM RANGE MODELS REMAIN SOMEWHAT SPLIT AS TO
HOW SIGNIFICANT A SOUTHERN STREAM SHORTWAVE WILL BE AS IT LIFTS INTO
THE DEVELOPING UPPER TROUGH OVER THE AREA. HOWEVER...GIVEN FACT THAT
00Z ECMWF/CANADIAN GEM NOAM BOTH DEVELOP A RATHER ROBUST STORM OVER
OR NEAR THE AREA BY WEDNESDAY AS THIS SOUTHERN ENERGY PHASES INTO
NORTHERN STREAM TROUGH...CONFIDENCE IS PERHAPS INCREASING SLIGHTLY
THAT A NOTEWORTHY STORM WILL WORK INTO/NEAR THE AREA BY MIDWEEK.
WHILE GFS DOES NOT SHARE THIS SOLUTION ATTM...AT LEAST HALF OF THE
ENSEMBLE MEMBERS DO TO A SIGNIFICANT DEGREE.

SUCH A SOLUTION WOULD BRING AN EXPANDING PRECIPITATION SHIELD INTO
THE AREA ON WEDNESDAY WITH A MIXTURE OF RAIN/SNOW CHANGING TO SNOW
WITH TIME AS THE SYSTEM INTENSIFIES AND LIFTS NORTH/NORTHEAST INTO
THE EASTERN GREAT LAKES/NORTHEAST CONUS INTO WEDNESDAY NIGHT. WHILE
THE ECMWF/NOAM CMC DO HAVE RATHER OMINOUS REPRESENTATIONS OF THIS
POTENTIAL WINTER STORM...A NUMBER OF SCENARIOS STILL REMAIN QUITE
PLAUSIBLE...RANGING FOR MINIMAL SOUTHERN DEVELOPMENT OF THIS
TROUGH TO THE SOUTHERN ENERGY SHIFTING EAST OF THE APPALACHIANS AND
THEN LIFTING UP/NEAR THE EASTERN SEABOARD. GIVEN THE UNCERTAINTY
OF A DAY 6 FORECAST...WILL NOT ADJUST FORECAST TOO ANY GREAT DEGREE
WITH THIS FORECAST PACKAGE. SUFFICE IT TO SAY THAT THE MIDWEEK
PERIOD NEXT WEEK DOES APPEAR TO BE RATHER ACTIVE FOR THE AREA AS
COMPARED TO THE CURRENT WEATHER REGIME.

&&

.MARINE...

SURFACE HIGH PRESSURE IS FORECASTED TO BUILD INTO THE AREA DURING
THE DAY TODAY AND THEN DRIFT EAST ACROSS THE CENTRAL AND EASTERN
GREAT LAKES OVER THE WEEKEND. THIS WILL LEAD TO EXCEEDINGLY CALM
CONDITIONS FOR THIS TIME OF YEAR...AT LEAST INTO MUCH OF SUNDAY.
SOUTHERLY WINDS WILL THEN BEGIN TO INCREASE ON THE BACKSIDE OF THIS
HIGH SUNDAY INTO MONDAY. EVEN SO...RATHER AGREEABLE MARINE
CONDITIONS ARE EXPECTED INTO EARLY NEXT WEEK AS WINDS/WAVES ONLY
INCREASE MARGINALLY WITHIN THIS DEVELOPING SOUTH/SOUTHEAST FLOW.

&&

.AVIATION...ISSUED 1154 PM EST THU DEC 18 2014

//DISCUSSION...

WEAK SURFACE TROUGHING SUSTAINING A LIGHT MIX OF FREEZING DRIZZLE
WITH SOME SNOWFLAKES EARLY THIS MORNING. THIS PRECIPITATION IS
EXPECTED TO DIMINISH IN COVERAGE THROUGH THE EARLY MORNING HOURS.
THE EXISTING DEEP PLUME OF LOW LEVEL MOISTURE AND ASSOCIATED MVFR
CEILING WILL BE SLOWER TO DECREASE. UPSTREAM SATELLITE TRENDS
WOULD BRING THE EDGE OF THE CLEARING LINE NOW MOVING THROUGH
NORTHERN LOWER INTO MBS BY DAYBREAK. MOISTURE MAY BE SLOWER TO
ERODE TOWARD THE SOUTH AND WILL MAINTAIN A MORE GRADUAL CLEARING
INTO THE REMAINDER OF SE MICHIGAN ON FRIDAY. A LIGHT WIND FIELD
THROUGH THE PERIOD.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW THROUGH 09-10Z.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING...LOW CONFIDENCE INTO THE AFTERNOON.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW EARLY THIS MORNING.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

SHORT TERM...SF
LONG TERM....DG
MARINE.......DG
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 190454
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1154 PM EST THU DEC 18 2014

.AVIATION...

//DISCUSSION...

WEAK SURFACE TROUGHING SUSTAINING A LIGHT MIX OF FREEZING DRIZZLE
WITH SOME SNOWFLAKES EARLY THIS MORNING. THIS PRECIPITATION IS
EXPECTED TO DIMINISH IN COVERAGE THROUGH THE EARLY MORNING HOURS.
THE EXISTING DEEP PLUME OF LOW LEVEL MOISTURE AND ASSOCIATED MVFR
CEILING WILL BE SLOWER TO DECREASE. UPSTREAM SATELLITE TRENDS
WOULD BRING THE EDGE OF THE CLEARING LINE NOW MOVING THROUGH
NORTHERN LOWER INTO MBS BY DAYBREAK. MOISTURE MAY BE SLOWER TO
ERODE TOWARD THE SOUTH AND WILL MAINTAIN A MORE GRADUAL CLEARING
INTO THE REMAINDER OF SE MICHIGAN ON FRIDAY. A LIGHT WIND FIELD
THROUGH THE PERIOD.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW THROUGH 09-10Z.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING...LOW CONFIDENCE INTO THE AFTERNOON.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW EARLY THIS MORNING.

&&

.PREV DISCUSSION...ISSUED 746 PM EST THU DEC 18 2014

UPDATE...

RECENT RADAR SHOWING A DEFINITIVE UPTICK IN A DEFINED STRIPE OF
FREEZING DRIZZLE...PERHAPS ARGUABLY CLOSER TO FREEZING RAIN GIVEN
THE RETURNS...NOW SHIFTING THROUGH SOUTHERN LIVINGSTON/NORTHERN
WASHTENAW. THIS FEATURE REMAINS ANCHORED WITHIN A LINEAR AXIS OF
ENHANCED LOW LEVEL CONVERGENCE ACCOMPANYING THE PASSAGE OF A
SFC-850 MB TROUGH. 18Z NAM AND RECENT RAP GUIDANCE SUGGEST THIS
FEATURE WILL SLOWLY TRANSLATE SOUTHWARD OVER THE NEXT SEVERAL
HOURS...EFFECTIVELY SUSTAINING A FAVORABLE ENVIRONMENT FOR
MAINTENANCE OF THIS ONGOING LIGHT PRECIPITATION. POCKETS OF LIGHT
FREEZING DRIZZLE MIXED WITH SOME SNOWFLAKES WILL CONTINUE
ELSEWHERE SOUTH OF I-69 THROUGH ROUGHLY THE MIDNIGHT
WINDOW...THEREAFTER A LOSS OF MOISTURE DEPTH THROUGH THE BASE OF
THE INVERSION LAYER AS POST-TROUGH WINDS FLIP TO NORTHERLY SHOULD
BRING A NORTH TO SOUTH DIMINISHING TREND. THE GOING CONDITIONS IN
LIVINGSTON/WASHTENAW LIKELY CLOSING IN ON THE EDGE OF A VERY
SHORT FUSED ADVISORY HEADLINE. CALLS TO BOTH COUNTIES INDICATE
SLICK SPOTS ON SOME BRIDGES/OVERPASSES WITH ASSOCIATED SPINOUTS.
THIS BAND DOES APPEAR TRANSIENT ENOUGH AND OF SHORT ENOUGH
DURATION AT THIS TIME TO HOLD TIGHT IN HANDLING THE SITUATION
WITH SPECIAL WEATHER STATEMENTS /SPSDTX/...BUT WILL CONTINUE TO
MONITOR.

PREV DISCUSSION...ISSUED 355 PM EST THU DEC 18 2014

SHORT TERM...TONIGHT

FREEZING DRIZZLE AND LIGHT SNOW ACROSS SOUTHEAST MICHIGAN IS SLOWLY
BECOMING LESS WIDESPREAD AS THE AFTERNOON PROGRESSES. THE MAIN
CONCERN FOR TONIGHT WILL BE TIMING THE ENDING OF THE FREEZING
DRIZZLE AND WHETHER CLOUDS WILL STICK AROUND. WHILE CURRENT
SATELLITE IMAGERY IS SHOWING DRIER AIR SLOWLY PROGRESSING SOUTHWARD
OUT OF CANADA...PROGRESSION IS REALLY SLOW AND CURRENTLY NOT
ANTICIPATING THE DRY SURGE TO REACH SOUTHEAST MICHIGAN UNTIL CLOSER
TO DAYBREAK FRIDAY MORNING. WITH THE LOW LEVEL MOISTURE STICKING
AROUND OVERNIGHT...LOW LEVEL STRATUS IS EXPECTED TO REMAIN OVER THE
CWA. THE CLOUDS WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH
OVERNIGHT AND HAVE THEREFORE OPTED TO SIDE ON THE WARMER SIDE OF
MODEL GUIDANCE FOR LOWS. EXPECT MID 20S ACROSS THE METRO DETROIT
AREA AND LOW TO MID 20S FOR THE REST OF THE CWA.

IN ADDITION...WHILE DRIZZLE IS DIMINISHING THE FORECASTED STRATUS
COULD RE-INITIATE DRIZZLE FOR THE EARLY PART OF THE EVENING. CURRENT
MODEL SOUNDINGS SHOW A WELL SATURATED BOUNDARY LAYER WITH LIGHT
WINDS OVER SOUTHEAST MICHIGAN THROUGH MOST OF THURSDAY EVENING WHICH
COULD HELP IN THE RE-DEVELOPMENT OF LIGHT DRIZZLE. AS TEMPERATURES
FALL BELOW FREEZING AFTER SUNSET...THE DRIZZLE COULD BECOME FREEZING
DRIZZLE AND MIX WITH SNOW ONCE AGAIN. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOW AT THIS FORECAST ISSUANCE AND HAVE ONLY INCLUDED
FREEZING DRIZZLE IN THE FORECAST THROUGH 00Z /7PM/ THURSDAY. WILL
HAVE TO MONITOR OVER THE NEXT SEVERAL HOURS TO SEE IF DRIZZLE STARTS
TO DEVELOP.

LONG TERM...FRIDAY THROUGH WEDNESDAY

THE UPPER LEVEL PATTERN OVER THE UPPER MIDWEST AND GREAT LAKES
STATES WILL DEAMPLIFY TO THE POINT THAT PSEUDO ZONAL FLOW WILL BE
THE PRIMARY SETUP THROUGH MUCH OF THE UPCOMING WEEKEND. THE MAIN
WESTERLY JET AXIS WILL RESIDE OVER THE SOUTHEASTERN UNITED STATES
WITH VERY NOISY SHORTWAVE ENERGY PASSING WITHIN A FADING MIDLEVEL
COL STRUCTURE. HIGH COLUMN STABILITY SEEMS TO BE THE PRIMARY DRIVER
OF A SURFACE ANTICYCLONE THAT WILL PASS DIRECTLY THROUGH
SOUTHEASTERN MICHIGAN. DEAMPLIFIED FLOW WEAK SHORTWAVE ENERGY AND
RESULTS IN VERY QUIET WEATHER THAT MAINTAINS A STATUS QUO FROM A
TEMPERATURE AND PRECIPITATION PERSPECTIVE.

THERE WILL STILL BE SOME FORECAST DIFFICULTY IN THE EXPECTED
PATTERN...PRIMARILY THAT OF CLOUDS AND CLOUD TRENDS. MODEL DATA IS
VERY AGGRESSIVE WITH A SOUTHWARD PUSH OF DRY AIR LATE
TONIGHT...MAKING INROADS OVER MANY AREAS PRIOR TO SUNRISE. PATTERN
RECOGNITION AND OBSERVATIONAL DATA SUGGESTS OTHERWISE...THE HEAVY
LOOK OF SHEARING OCCURRING ALONG A MIDLEVEL CONVERGENCE BOUNDARY
THAT IS SUPPORTING THE SURFACE TROUGH AND CONTINUATION OF
REFLECTIVITY FINELINE. THE PROBLEM WITH THIS SURFACE TROUGH IS
THAT IT CONTINUES TO HOLD ON STRONGER THAN ANY OF THE MODEL
SOLUTIONS HAVE BEEN SUPPORTING. RH AND SPECIFIC HUMIDITY ANALYSES
SUGGESTS THAT CLEARING MAY BE DOWN TO THE M59 CORRIDOR BY SUNRISE
WITH CLOUDS SOLIDLY LOCKED IN OVER THE CENTRAL DETROIT METRO AREA
SOUTHWARD. THE CLEARING TREND MAY THEN ACCELERATE FOR THESE
SOUTHERN LOCATIONS AS WE HEAD INTO FRIDAY EVENING. FINALLY...COULD
BE LOOKING AT A PERIOD OF CLEAR SKIES FRIDAY NIGHT AND INTO THE
FIRST PART OF SATURDAY. LONGWAVE HEIGHT REBOUND AND WIND DIRECTION
CHANGE TO THE SOUTH BY LATE SATURDAY SUPPORTS THE RETURN OF
ORGANIZED MOISTURE ADVECTION AND CLOUDS.

ACTIVE WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST. THIS
WILL OCCUR AS A STRONG PACIFIC JET ENTERS THE PACIFIC
NORTHWEST...DEEPENS THE LONGWAVE TROUGH OVER THE CENTRAL CONUS...AND
EVENTUALLY CAUSES THE TROUGH TO BECOME NEGATIVELY TILTED AS THE JET
ENERGY ROUNDS THE BASE OF THE TROUGH TOWARD CHRISTMAS EVE. AT THE
SURFACE...A WEAKER LOW PRESSURE SYSTEM WILL EVOLVE OVER THE NORTHERN
PLAINS MONDAY/TUESDAY...EVENTUALLY GETTING ABSORBED BY A POTENTIALLY
STRONGER STORM LIFTING NORTHWARD FROM THE DEEP SOUTH. STILL LOTS OF
POSSIBLE SOLUTIONS AS TO HOW/WHERE THIS INTERACTION TAKES PLACE SO
THE DETAILS ARE FAR FROM BEING CLEAR. AT THIS POINT WILL HIGHLIGHT
THE POTENTIAL FOR IMPACTFUL WEATHER CENTERED AROUND
TUESDAY/WEDNESDAY. IMPACTS IN TERMS OF PRECIPITATION WILL BE MOST
LIKELY DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
MODEL CONSENSUS...WEAK AS IT IS AT THIS POINT...SUGGESTS WE HAVE A
BETTER CHANCE OF BEING ON THE WARMER SIDE OF THIS SYSTEM MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH COLDER AIR AND BREEZY CONDITIONS
BY CHRISTMAS EVE.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT...MAINTAINING
RELATIVELY RELAXED NORTHERLY WINDS FOR THE TIME OF YEAR. THE SURFACE
HIGH IS FORECASTED TO DRIFT ACROSS THE CENTRAL GREAT LAKES THIS
WEEKEND WITH SOUTHERLY FLOW EVENTUALLY RETURNING ON SUNDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....MR
UPDATE.......MR
SHORT TERM...RK
LONG TERM....CB/DT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 190454
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1154 PM EST THU DEC 18 2014

.AVIATION...

//DISCUSSION...

WEAK SURFACE TROUGHING SUSTAINING A LIGHT MIX OF FREEZING DRIZZLE
WITH SOME SNOWFLAKES EARLY THIS MORNING. THIS PRECIPITATION IS
EXPECTED TO DIMINISH IN COVERAGE THROUGH THE EARLY MORNING HOURS.
THE EXISTING DEEP PLUME OF LOW LEVEL MOISTURE AND ASSOCIATED MVFR
CEILING WILL BE SLOWER TO DECREASE. UPSTREAM SATELLITE TRENDS
WOULD BRING THE EDGE OF THE CLEARING LINE NOW MOVING THROUGH
NORTHERN LOWER INTO MBS BY DAYBREAK. MOISTURE MAY BE SLOWER TO
ERODE TOWARD THE SOUTH AND WILL MAINTAIN A MORE GRADUAL CLEARING
INTO THE REMAINDER OF SE MICHIGAN ON FRIDAY. A LIGHT WIND FIELD
THROUGH THE PERIOD.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW THROUGH 09-10Z.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING...LOW CONFIDENCE INTO THE AFTERNOON.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW EARLY THIS MORNING.

&&

.PREV DISCUSSION...ISSUED 746 PM EST THU DEC 18 2014

UPDATE...

RECENT RADAR SHOWING A DEFINITIVE UPTICK IN A DEFINED STRIPE OF
FREEZING DRIZZLE...PERHAPS ARGUABLY CLOSER TO FREEZING RAIN GIVEN
THE RETURNS...NOW SHIFTING THROUGH SOUTHERN LIVINGSTON/NORTHERN
WASHTENAW. THIS FEATURE REMAINS ANCHORED WITHIN A LINEAR AXIS OF
ENHANCED LOW LEVEL CONVERGENCE ACCOMPANYING THE PASSAGE OF A
SFC-850 MB TROUGH. 18Z NAM AND RECENT RAP GUIDANCE SUGGEST THIS
FEATURE WILL SLOWLY TRANSLATE SOUTHWARD OVER THE NEXT SEVERAL
HOURS...EFFECTIVELY SUSTAINING A FAVORABLE ENVIRONMENT FOR
MAINTENANCE OF THIS ONGOING LIGHT PRECIPITATION. POCKETS OF LIGHT
FREEZING DRIZZLE MIXED WITH SOME SNOWFLAKES WILL CONTINUE
ELSEWHERE SOUTH OF I-69 THROUGH ROUGHLY THE MIDNIGHT
WINDOW...THEREAFTER A LOSS OF MOISTURE DEPTH THROUGH THE BASE OF
THE INVERSION LAYER AS POST-TROUGH WINDS FLIP TO NORTHERLY SHOULD
BRING A NORTH TO SOUTH DIMINISHING TREND. THE GOING CONDITIONS IN
LIVINGSTON/WASHTENAW LIKELY CLOSING IN ON THE EDGE OF A VERY
SHORT FUSED ADVISORY HEADLINE. CALLS TO BOTH COUNTIES INDICATE
SLICK SPOTS ON SOME BRIDGES/OVERPASSES WITH ASSOCIATED SPINOUTS.
THIS BAND DOES APPEAR TRANSIENT ENOUGH AND OF SHORT ENOUGH
DURATION AT THIS TIME TO HOLD TIGHT IN HANDLING THE SITUATION
WITH SPECIAL WEATHER STATEMENTS /SPSDTX/...BUT WILL CONTINUE TO
MONITOR.

PREV DISCUSSION...ISSUED 355 PM EST THU DEC 18 2014

SHORT TERM...TONIGHT

FREEZING DRIZZLE AND LIGHT SNOW ACROSS SOUTHEAST MICHIGAN IS SLOWLY
BECOMING LESS WIDESPREAD AS THE AFTERNOON PROGRESSES. THE MAIN
CONCERN FOR TONIGHT WILL BE TIMING THE ENDING OF THE FREEZING
DRIZZLE AND WHETHER CLOUDS WILL STICK AROUND. WHILE CURRENT
SATELLITE IMAGERY IS SHOWING DRIER AIR SLOWLY PROGRESSING SOUTHWARD
OUT OF CANADA...PROGRESSION IS REALLY SLOW AND CURRENTLY NOT
ANTICIPATING THE DRY SURGE TO REACH SOUTHEAST MICHIGAN UNTIL CLOSER
TO DAYBREAK FRIDAY MORNING. WITH THE LOW LEVEL MOISTURE STICKING
AROUND OVERNIGHT...LOW LEVEL STRATUS IS EXPECTED TO REMAIN OVER THE
CWA. THE CLOUDS WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH
OVERNIGHT AND HAVE THEREFORE OPTED TO SIDE ON THE WARMER SIDE OF
MODEL GUIDANCE FOR LOWS. EXPECT MID 20S ACROSS THE METRO DETROIT
AREA AND LOW TO MID 20S FOR THE REST OF THE CWA.

IN ADDITION...WHILE DRIZZLE IS DIMINISHING THE FORECASTED STRATUS
COULD RE-INITIATE DRIZZLE FOR THE EARLY PART OF THE EVENING. CURRENT
MODEL SOUNDINGS SHOW A WELL SATURATED BOUNDARY LAYER WITH LIGHT
WINDS OVER SOUTHEAST MICHIGAN THROUGH MOST OF THURSDAY EVENING WHICH
COULD HELP IN THE RE-DEVELOPMENT OF LIGHT DRIZZLE. AS TEMPERATURES
FALL BELOW FREEZING AFTER SUNSET...THE DRIZZLE COULD BECOME FREEZING
DRIZZLE AND MIX WITH SNOW ONCE AGAIN. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOW AT THIS FORECAST ISSUANCE AND HAVE ONLY INCLUDED
FREEZING DRIZZLE IN THE FORECAST THROUGH 00Z /7PM/ THURSDAY. WILL
HAVE TO MONITOR OVER THE NEXT SEVERAL HOURS TO SEE IF DRIZZLE STARTS
TO DEVELOP.

LONG TERM...FRIDAY THROUGH WEDNESDAY

THE UPPER LEVEL PATTERN OVER THE UPPER MIDWEST AND GREAT LAKES
STATES WILL DEAMPLIFY TO THE POINT THAT PSEUDO ZONAL FLOW WILL BE
THE PRIMARY SETUP THROUGH MUCH OF THE UPCOMING WEEKEND. THE MAIN
WESTERLY JET AXIS WILL RESIDE OVER THE SOUTHEASTERN UNITED STATES
WITH VERY NOISY SHORTWAVE ENERGY PASSING WITHIN A FADING MIDLEVEL
COL STRUCTURE. HIGH COLUMN STABILITY SEEMS TO BE THE PRIMARY DRIVER
OF A SURFACE ANTICYCLONE THAT WILL PASS DIRECTLY THROUGH
SOUTHEASTERN MICHIGAN. DEAMPLIFIED FLOW WEAK SHORTWAVE ENERGY AND
RESULTS IN VERY QUIET WEATHER THAT MAINTAINS A STATUS QUO FROM A
TEMPERATURE AND PRECIPITATION PERSPECTIVE.

THERE WILL STILL BE SOME FORECAST DIFFICULTY IN THE EXPECTED
PATTERN...PRIMARILY THAT OF CLOUDS AND CLOUD TRENDS. MODEL DATA IS
VERY AGGRESSIVE WITH A SOUTHWARD PUSH OF DRY AIR LATE
TONIGHT...MAKING INROADS OVER MANY AREAS PRIOR TO SUNRISE. PATTERN
RECOGNITION AND OBSERVATIONAL DATA SUGGESTS OTHERWISE...THE HEAVY
LOOK OF SHEARING OCCURRING ALONG A MIDLEVEL CONVERGENCE BOUNDARY
THAT IS SUPPORTING THE SURFACE TROUGH AND CONTINUATION OF
REFLECTIVITY FINELINE. THE PROBLEM WITH THIS SURFACE TROUGH IS
THAT IT CONTINUES TO HOLD ON STRONGER THAN ANY OF THE MODEL
SOLUTIONS HAVE BEEN SUPPORTING. RH AND SPECIFIC HUMIDITY ANALYSES
SUGGESTS THAT CLEARING MAY BE DOWN TO THE M59 CORRIDOR BY SUNRISE
WITH CLOUDS SOLIDLY LOCKED IN OVER THE CENTRAL DETROIT METRO AREA
SOUTHWARD. THE CLEARING TREND MAY THEN ACCELERATE FOR THESE
SOUTHERN LOCATIONS AS WE HEAD INTO FRIDAY EVENING. FINALLY...COULD
BE LOOKING AT A PERIOD OF CLEAR SKIES FRIDAY NIGHT AND INTO THE
FIRST PART OF SATURDAY. LONGWAVE HEIGHT REBOUND AND WIND DIRECTION
CHANGE TO THE SOUTH BY LATE SATURDAY SUPPORTS THE RETURN OF
ORGANIZED MOISTURE ADVECTION AND CLOUDS.

ACTIVE WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST. THIS
WILL OCCUR AS A STRONG PACIFIC JET ENTERS THE PACIFIC
NORTHWEST...DEEPENS THE LONGWAVE TROUGH OVER THE CENTRAL CONUS...AND
EVENTUALLY CAUSES THE TROUGH TO BECOME NEGATIVELY TILTED AS THE JET
ENERGY ROUNDS THE BASE OF THE TROUGH TOWARD CHRISTMAS EVE. AT THE
SURFACE...A WEAKER LOW PRESSURE SYSTEM WILL EVOLVE OVER THE NORTHERN
PLAINS MONDAY/TUESDAY...EVENTUALLY GETTING ABSORBED BY A POTENTIALLY
STRONGER STORM LIFTING NORTHWARD FROM THE DEEP SOUTH. STILL LOTS OF
POSSIBLE SOLUTIONS AS TO HOW/WHERE THIS INTERACTION TAKES PLACE SO
THE DETAILS ARE FAR FROM BEING CLEAR. AT THIS POINT WILL HIGHLIGHT
THE POTENTIAL FOR IMPACTFUL WEATHER CENTERED AROUND
TUESDAY/WEDNESDAY. IMPACTS IN TERMS OF PRECIPITATION WILL BE MOST
LIKELY DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
MODEL CONSENSUS...WEAK AS IT IS AT THIS POINT...SUGGESTS WE HAVE A
BETTER CHANCE OF BEING ON THE WARMER SIDE OF THIS SYSTEM MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH COLDER AIR AND BREEZY CONDITIONS
BY CHRISTMAS EVE.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT...MAINTAINING
RELATIVELY RELAXED NORTHERLY WINDS FOR THE TIME OF YEAR. THE SURFACE
HIGH IS FORECASTED TO DRIFT ACROSS THE CENTRAL GREAT LAKES THIS
WEEKEND WITH SOUTHERLY FLOW EVENTUALLY RETURNING ON SUNDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....MR
UPDATE.......MR
SHORT TERM...RK
LONG TERM....CB/DT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 190046
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
746 PM EST THU DEC 18 2014

.UPDATE...

RECENT RADAR SHOWING A DEFINITIVE UPTICK IN A DEFINED STRIPE OF
FREEZING DRIZZLE...PERHAPS ARGUABLY CLOSER TO FREEZING RAIN GIVEN
THE RETURNS...NOW SHIFTING THROUGH SOUTHERN LIVINGSTON/NORTHERN
WASHTENAW. THIS FEATURE REMAINS ANCHORED WITHIN A LINEAR AXIS OF
ENHANCED LOW LEVEL CONVERGENCE ACCOMPANYING THE PASSAGE OF A
SFC-850 MB TROUGH. 18Z NAM AND RECENT RAP GUIDANCE SUGGEST THIS
FEATURE WILL SLOWLY TRANSLATE SOUTHWARD OVER THE NEXT SEVERAL
HOURS...EFFECTIVELY SUSTAINING A FAVORABLE ENVIRONMENT FOR
MAINTENANCE OF THIS ONGOING LIGHT PRECIPITATION. POCKETS OF LIGHT
FREEZING DRIZZLE MIXED WITH SOME SNOWFLAKES WILL CONTINUE
ELSEWHERE SOUTH OF I-69 THROUGH ROUGHLY THE MIDNIGHT
WINDOW...THEREAFTER A LOSS OF MOISTURE DEPTH THROUGH THE BASE OF
THE INVERSION LAYER AS POST-TROUGH WINDS FLIP TO NORTHERLY SHOULD
BRING A NORTH TO SOUTH DIMINISHING TREND. THE GOING CONDITIONS IN
LIVINGSTON/WASHTENAW LIKELY CLOSING IN ON THE EDGE OF A VERY
SHORT FUSED ADVISORY HEADLINE. CALLS TO BOTH COUNTIES INDICATE
SLICK SPOTS ON SOME BRIDGES/OVERPASSES WITH ASSOCIATED SPINOUTS.
THIS BAND DOES APPEAR TRANSIENT ENOUGH AND OF SHORT ENOUGH
DURATION AT THIS TIME TO HOLD TIGHT IN HANDLING THE SITUATION
WITH SPECIAL WEATHER STATEMENTS /SPSDTX/...BUT WILL CONTINUE TO
MONITOR.

&&

.AVIATION...ISSUED 641 PM EST THU DEC 18 2014

//DISCUSSION...

DEEP PLUME OF LOW LEVEL MOISTURE TUCKED BENEATH A STRONG INVERSION
WILL HOLD FIRM TONIGHT.  RECENT OBSERVATIONS AND RADAR DATA CONTINUE
TO DISPLAY A COMBINATION OF LIGHT FREEZING DRIZZLE AND SNOWFLAKES
WITHIN THE RESULTANT LOW STRATUS FIELD.  THE OVERALL COVERAGE PER
LATEST TRENDS DO SUPPORT A TEMPO INCLUSION PRIOR TO MIDNIGHT FROM
FLINT SOUTHWARD.   CEILINGS AT FNT/PTK WILL FLUCTUATE WITHIN IFR/LOW
MVFR THROUGH THIS TIME...LOWER MVFR ELSEWHERE.  DRIER AIR WILL BEGIN
TO ERODE THIS MOIST LAYER FROM ABOVE THROUGH THE EARLY MORNING
PERIOD.  THIS WILL BRING A DIMINISHING TREND TO THE LIGHT
PRECIPITATION COVERAGE...ALTHOUGH THE EXISTING MVFR STRATUS WILL
LIKELY STRUGGLE TO SCATTER UNTIL WELL INTO FRIDAY.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW EARLY TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW THROUGH MIDNIGHT.

&&

.PREV DISCUSSION...ISSUED 355 PM EST THU DEC 18 2014

SHORT TERM...TONIGHT

FREEZING DRIZZLE AND LIGHT SNOW ACROSS SOUTHEAST MICHIGAN IS SLOWLY
BECOMING LESS WIDESPREAD AS THE AFTERNOON PROGRESSES. THE MAIN
CONCERN FOR TONIGHT WILL BE TIMING THE ENDING OF THE FREEZING
DRIZZLE AND WHETHER CLOUDS WILL STICK AROUND. WHILE CURRENT
SATELLITE IMAGERY IS SHOWING DRIER AIR SLOWLY PROGRESSING SOUTHWARD
OUT OF CANADA...PROGRESSION IS REALLY SLOW AND CURRENTLY NOT
ANTICIPATING THE DRY SURGE TO REACH SOUTHEAST MICHIGAN UNTIL CLOSER
TO DAYBREAK FRIDAY MORNING. WITH THE LOW LEVEL MOISTURE STICKING
AROUND OVERNIGHT...LOW LEVEL STRATUS IS EXPECTED TO REMAIN OVER THE
CWA. THE CLOUDS WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH
OVERNIGHT AND HAVE THEREFORE OPTED TO SIDE ON THE WARMER SIDE OF
MODEL GUIDANCE FOR LOWS. EXPECT MID 20S ACROSS THE METRO DETROIT
AREA AND LOW TO MID 20S FOR THE REST OF THE CWA.

IN ADDITION...WHILE DRIZZLE IS DIMINISHING THE FORECASTED STRATUS
COULD RE-INITIATE DRIZZLE FOR THE EARLY PART OF THE EVENING. CURRENT
MODEL SOUNDINGS SHOW A WELL SATURATED BOUNDARY LAYER WITH LIGHT
WINDS OVER SOUTHEAST MICHIGAN THROUGH MOST OF THURSDAY EVENING WHICH
COULD HELP IN THE RE-DEVELOPMENT OF LIGHT DRIZZLE. AS TEMPERATURES
FALL BELOW FREEZING AFTER SUNSET...THE DRIZZLE COULD BECOME FREEZING
DRIZZLE AND MIX WITH SNOW ONCE AGAIN. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOW AT THIS FORECAST ISSUANCE AND HAVE ONLY INCLUDED
FREEZING DRIZZLE IN THE FORECAST THROUGH 00Z /7PM/ THURSDAY. WILL
HAVE TO MONITOR OVER THE NEXT SEVERAL HOURS TO SEE IF DRIZZLE STARTS
TO DEVELOP.

LONG TERM...FRIDAY THROUGH WEDNESDAY

THE UPPER LEVEL PATTERN OVER THE UPPER MIDWEST AND GREAT LAKES
STATES WILL DEAMPLIFY TO THE POINT THAT PSEUDO ZONAL FLOW WILL BE
THE PRIMARY SETUP THROUGH MUCH OF THE UPCOMING WEEKEND. THE MAIN
WESTERLY JET AXIS WILL RESIDE OVER THE SOUTHEASTERN UNITED STATES
WITH VERY NOISY SHORTWAVE ENERGY PASSING WITHIN A FADING MIDLEVEL
COL STRUCTURE. HIGH COLUMN STABILITY SEEMS TO BE THE PRIMARY DRIVER
OF A SURFACE ANTICYCLONE THAT WILL PASS DIRECTLY THROUGH
SOUTHEASTERN MICHIGAN. DEAMPLIFIED FLOW WEAK SHORTWAVE ENERGY AND
RESULTS IN VERY QUIET WEATHER THAT MAINTAINS A STATUS QUO FROM A
TEMPERATURE AND PRECIPITATION PERSPECTIVE.

THERE WILL STILL BE SOME FORECAST DIFFICULTY IN THE EXPECTED
PATTERN...PRIMARILY THAT OF CLOUDS AND CLOUD TRENDS. MODEL DATA IS
VERY AGGRESSIVE WITH A SOUTHWARD PUSH OF DRY AIR LATE
TONIGHT...MAKING INROADS OVER MANY AREAS PRIOR TO SUNRISE. PATTERN
RECOGNITION AND OBSERVATIONAL DATA SUGGESTS OTHERWISE...THE HEAVY
LOOK OF SHEARING OCCURRING ALONG A MIDLEVEL CONVERGENCE BOUNDARY
THAT IS SUPPORTING THE SURFACE TROUGH AND CONTINUATION OF
REFLECTIVITY FINELINE. THE PROBLEM WITH THIS SURFACE TROUGH IS
THAT IT CONTINUES TO HOLD ON STRONGER THAN ANY OF THE MODEL
SOLUTIONS HAVE BEEN SUPPORTING. RH AND SPECIFIC HUMIDITY ANALYSES
SUGGESTS THAT CLEARING MAY BE DOWN TO THE M59 CORRIDOR BY SUNRISE
WITH CLOUDS SOLIDLY LOCKED IN OVER THE CENTRAL DETROIT METRO AREA
SOUTHWARD. THE CLEARING TREND MAY THEN ACCELERATE FOR THESE
SOUTHERN LOCATIONS AS WE HEAD INTO FRIDAY EVENING. FINALLY...COULD
BE LOOKING AT A PERIOD OF CLEAR SKIES FRIDAY NIGHT AND INTO THE
FIRST PART OF SATURDAY. LONGWAVE HEIGHT REBOUND AND WIND DIRECTION
CHANGE TO THE SOUTH BY LATE SATURDAY SUPPORTS THE RETURN OF
ORGANIZED MOISTURE ADVECTION AND CLOUDS.

ACTIVE WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST. THIS
WILL OCCUR AS A STRONG PACIFIC JET ENTERS THE PACIFIC
NORTHWEST...DEEPENS THE LONGWAVE TROUGH OVER THE CENTRAL CONUS...AND
EVENTUALLY CAUSES THE TROUGH TO BECOME NEGATIVELY TILTED AS THE JET
ENERGY ROUNDS THE BASE OF THE TROUGH TOWARD CHRISTMAS EVE. AT THE
SURFACE...A WEAKER LOW PRESSURE SYSTEM WILL EVOLVE OVER THE NORTHERN
PLAINS MONDAY/TUESDAY...EVENTUALLY GETTING ABSORBED BY A POTENTIALLY
STRONGER STORM LIFTING NORTHWARD FROM THE DEEP SOUTH. STILL LOTS OF
POSSIBLE SOLUTIONS AS TO HOW/WHERE THIS INTERACTION TAKES PLACE SO
THE DETAILS ARE FAR FROM BEING CLEAR. AT THIS POINT WILL HIGHLIGHT
THE POTENTIAL FOR IMPACTFUL WEATHER CENTERED AROUND
TUESDAY/WEDNESDAY. IMPACTS IN TERMS OF PRECIPITATION WILL BE MOST
LIKELY DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
MODEL CONSENSUS...WEAK AS IT IS AT THIS POINT...SUGGESTS WE HAVE A
BETTER CHANCE OF BEING ON THE WARMER SIDE OF THIS SYSTEM MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH COLDER AIR AND BREEZY CONDITIONS
BY CHRISTMAS EVE.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT...MAINTAINING
RELATIVELY RELAXED NORTHERLY WINDS FOR THE TIME OF YEAR. THE SURFACE
HIGH IS FORECASTED TO DRIFT ACROSS THE CENTRAL GREAT LAKES THIS
WEEKEND WITH SOUTHERLY FLOW EVENTUALLY RETURNING ON SUNDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

UPDATE.......MR
AVIATION.....MR
SHORT TERM...RK
LONG TERM....CB/DT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 190046
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
746 PM EST THU DEC 18 2014

.UPDATE...

RECENT RADAR SHOWING A DEFINITIVE UPTICK IN A DEFINED STRIPE OF
FREEZING DRIZZLE...PERHAPS ARGUABLY CLOSER TO FREEZING RAIN GIVEN
THE RETURNS...NOW SHIFTING THROUGH SOUTHERN LIVINGSTON/NORTHERN
WASHTENAW. THIS FEATURE REMAINS ANCHORED WITHIN A LINEAR AXIS OF
ENHANCED LOW LEVEL CONVERGENCE ACCOMPANYING THE PASSAGE OF A
SFC-850 MB TROUGH. 18Z NAM AND RECENT RAP GUIDANCE SUGGEST THIS
FEATURE WILL SLOWLY TRANSLATE SOUTHWARD OVER THE NEXT SEVERAL
HOURS...EFFECTIVELY SUSTAINING A FAVORABLE ENVIRONMENT FOR
MAINTENANCE OF THIS ONGOING LIGHT PRECIPITATION. POCKETS OF LIGHT
FREEZING DRIZZLE MIXED WITH SOME SNOWFLAKES WILL CONTINUE
ELSEWHERE SOUTH OF I-69 THROUGH ROUGHLY THE MIDNIGHT
WINDOW...THEREAFTER A LOSS OF MOISTURE DEPTH THROUGH THE BASE OF
THE INVERSION LAYER AS POST-TROUGH WINDS FLIP TO NORTHERLY SHOULD
BRING A NORTH TO SOUTH DIMINISHING TREND. THE GOING CONDITIONS IN
LIVINGSTON/WASHTENAW LIKELY CLOSING IN ON THE EDGE OF A VERY
SHORT FUSED ADVISORY HEADLINE. CALLS TO BOTH COUNTIES INDICATE
SLICK SPOTS ON SOME BRIDGES/OVERPASSES WITH ASSOCIATED SPINOUTS.
THIS BAND DOES APPEAR TRANSIENT ENOUGH AND OF SHORT ENOUGH
DURATION AT THIS TIME TO HOLD TIGHT IN HANDLING THE SITUATION
WITH SPECIAL WEATHER STATEMENTS /SPSDTX/...BUT WILL CONTINUE TO
MONITOR.

&&

.AVIATION...ISSUED 641 PM EST THU DEC 18 2014

//DISCUSSION...

DEEP PLUME OF LOW LEVEL MOISTURE TUCKED BENEATH A STRONG INVERSION
WILL HOLD FIRM TONIGHT.  RECENT OBSERVATIONS AND RADAR DATA CONTINUE
TO DISPLAY A COMBINATION OF LIGHT FREEZING DRIZZLE AND SNOWFLAKES
WITHIN THE RESULTANT LOW STRATUS FIELD.  THE OVERALL COVERAGE PER
LATEST TRENDS DO SUPPORT A TEMPO INCLUSION PRIOR TO MIDNIGHT FROM
FLINT SOUTHWARD.   CEILINGS AT FNT/PTK WILL FLUCTUATE WITHIN IFR/LOW
MVFR THROUGH THIS TIME...LOWER MVFR ELSEWHERE.  DRIER AIR WILL BEGIN
TO ERODE THIS MOIST LAYER FROM ABOVE THROUGH THE EARLY MORNING
PERIOD.  THIS WILL BRING A DIMINISHING TREND TO THE LIGHT
PRECIPITATION COVERAGE...ALTHOUGH THE EXISTING MVFR STRATUS WILL
LIKELY STRUGGLE TO SCATTER UNTIL WELL INTO FRIDAY.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW EARLY TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW THROUGH MIDNIGHT.

&&

.PREV DISCUSSION...ISSUED 355 PM EST THU DEC 18 2014

SHORT TERM...TONIGHT

FREEZING DRIZZLE AND LIGHT SNOW ACROSS SOUTHEAST MICHIGAN IS SLOWLY
BECOMING LESS WIDESPREAD AS THE AFTERNOON PROGRESSES. THE MAIN
CONCERN FOR TONIGHT WILL BE TIMING THE ENDING OF THE FREEZING
DRIZZLE AND WHETHER CLOUDS WILL STICK AROUND. WHILE CURRENT
SATELLITE IMAGERY IS SHOWING DRIER AIR SLOWLY PROGRESSING SOUTHWARD
OUT OF CANADA...PROGRESSION IS REALLY SLOW AND CURRENTLY NOT
ANTICIPATING THE DRY SURGE TO REACH SOUTHEAST MICHIGAN UNTIL CLOSER
TO DAYBREAK FRIDAY MORNING. WITH THE LOW LEVEL MOISTURE STICKING
AROUND OVERNIGHT...LOW LEVEL STRATUS IS EXPECTED TO REMAIN OVER THE
CWA. THE CLOUDS WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH
OVERNIGHT AND HAVE THEREFORE OPTED TO SIDE ON THE WARMER SIDE OF
MODEL GUIDANCE FOR LOWS. EXPECT MID 20S ACROSS THE METRO DETROIT
AREA AND LOW TO MID 20S FOR THE REST OF THE CWA.

IN ADDITION...WHILE DRIZZLE IS DIMINISHING THE FORECASTED STRATUS
COULD RE-INITIATE DRIZZLE FOR THE EARLY PART OF THE EVENING. CURRENT
MODEL SOUNDINGS SHOW A WELL SATURATED BOUNDARY LAYER WITH LIGHT
WINDS OVER SOUTHEAST MICHIGAN THROUGH MOST OF THURSDAY EVENING WHICH
COULD HELP IN THE RE-DEVELOPMENT OF LIGHT DRIZZLE. AS TEMPERATURES
FALL BELOW FREEZING AFTER SUNSET...THE DRIZZLE COULD BECOME FREEZING
DRIZZLE AND MIX WITH SNOW ONCE AGAIN. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOW AT THIS FORECAST ISSUANCE AND HAVE ONLY INCLUDED
FREEZING DRIZZLE IN THE FORECAST THROUGH 00Z /7PM/ THURSDAY. WILL
HAVE TO MONITOR OVER THE NEXT SEVERAL HOURS TO SEE IF DRIZZLE STARTS
TO DEVELOP.

LONG TERM...FRIDAY THROUGH WEDNESDAY

THE UPPER LEVEL PATTERN OVER THE UPPER MIDWEST AND GREAT LAKES
STATES WILL DEAMPLIFY TO THE POINT THAT PSEUDO ZONAL FLOW WILL BE
THE PRIMARY SETUP THROUGH MUCH OF THE UPCOMING WEEKEND. THE MAIN
WESTERLY JET AXIS WILL RESIDE OVER THE SOUTHEASTERN UNITED STATES
WITH VERY NOISY SHORTWAVE ENERGY PASSING WITHIN A FADING MIDLEVEL
COL STRUCTURE. HIGH COLUMN STABILITY SEEMS TO BE THE PRIMARY DRIVER
OF A SURFACE ANTICYCLONE THAT WILL PASS DIRECTLY THROUGH
SOUTHEASTERN MICHIGAN. DEAMPLIFIED FLOW WEAK SHORTWAVE ENERGY AND
RESULTS IN VERY QUIET WEATHER THAT MAINTAINS A STATUS QUO FROM A
TEMPERATURE AND PRECIPITATION PERSPECTIVE.

THERE WILL STILL BE SOME FORECAST DIFFICULTY IN THE EXPECTED
PATTERN...PRIMARILY THAT OF CLOUDS AND CLOUD TRENDS. MODEL DATA IS
VERY AGGRESSIVE WITH A SOUTHWARD PUSH OF DRY AIR LATE
TONIGHT...MAKING INROADS OVER MANY AREAS PRIOR TO SUNRISE. PATTERN
RECOGNITION AND OBSERVATIONAL DATA SUGGESTS OTHERWISE...THE HEAVY
LOOK OF SHEARING OCCURRING ALONG A MIDLEVEL CONVERGENCE BOUNDARY
THAT IS SUPPORTING THE SURFACE TROUGH AND CONTINUATION OF
REFLECTIVITY FINELINE. THE PROBLEM WITH THIS SURFACE TROUGH IS
THAT IT CONTINUES TO HOLD ON STRONGER THAN ANY OF THE MODEL
SOLUTIONS HAVE BEEN SUPPORTING. RH AND SPECIFIC HUMIDITY ANALYSES
SUGGESTS THAT CLEARING MAY BE DOWN TO THE M59 CORRIDOR BY SUNRISE
WITH CLOUDS SOLIDLY LOCKED IN OVER THE CENTRAL DETROIT METRO AREA
SOUTHWARD. THE CLEARING TREND MAY THEN ACCELERATE FOR THESE
SOUTHERN LOCATIONS AS WE HEAD INTO FRIDAY EVENING. FINALLY...COULD
BE LOOKING AT A PERIOD OF CLEAR SKIES FRIDAY NIGHT AND INTO THE
FIRST PART OF SATURDAY. LONGWAVE HEIGHT REBOUND AND WIND DIRECTION
CHANGE TO THE SOUTH BY LATE SATURDAY SUPPORTS THE RETURN OF
ORGANIZED MOISTURE ADVECTION AND CLOUDS.

ACTIVE WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST. THIS
WILL OCCUR AS A STRONG PACIFIC JET ENTERS THE PACIFIC
NORTHWEST...DEEPENS THE LONGWAVE TROUGH OVER THE CENTRAL CONUS...AND
EVENTUALLY CAUSES THE TROUGH TO BECOME NEGATIVELY TILTED AS THE JET
ENERGY ROUNDS THE BASE OF THE TROUGH TOWARD CHRISTMAS EVE. AT THE
SURFACE...A WEAKER LOW PRESSURE SYSTEM WILL EVOLVE OVER THE NORTHERN
PLAINS MONDAY/TUESDAY...EVENTUALLY GETTING ABSORBED BY A POTENTIALLY
STRONGER STORM LIFTING NORTHWARD FROM THE DEEP SOUTH. STILL LOTS OF
POSSIBLE SOLUTIONS AS TO HOW/WHERE THIS INTERACTION TAKES PLACE SO
THE DETAILS ARE FAR FROM BEING CLEAR. AT THIS POINT WILL HIGHLIGHT
THE POTENTIAL FOR IMPACTFUL WEATHER CENTERED AROUND
TUESDAY/WEDNESDAY. IMPACTS IN TERMS OF PRECIPITATION WILL BE MOST
LIKELY DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
MODEL CONSENSUS...WEAK AS IT IS AT THIS POINT...SUGGESTS WE HAVE A
BETTER CHANCE OF BEING ON THE WARMER SIDE OF THIS SYSTEM MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH COLDER AIR AND BREEZY CONDITIONS
BY CHRISTMAS EVE.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT...MAINTAINING
RELATIVELY RELAXED NORTHERLY WINDS FOR THE TIME OF YEAR. THE SURFACE
HIGH IS FORECASTED TO DRIFT ACROSS THE CENTRAL GREAT LAKES THIS
WEEKEND WITH SOUTHERLY FLOW EVENTUALLY RETURNING ON SUNDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

UPDATE.......MR
AVIATION.....MR
SHORT TERM...RK
LONG TERM....CB/DT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 182341
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
641 PM EST THU DEC 18 2014

.AVIATION...

//DISCUSSION...

DEEP PLUME OF LOW LEVEL MOISTURE TUCKED BENEATH A STRONG INVERSION
WILL HOLD FIRM TONIGHT.  RECENT OBSERVATIONS AND RADAR DATA CONTINUE
TO DISPLAY A COMBINATION OF LIGHT FREEZING DRIZZLE AND SNOWFLAKES
WITHIN THE RESULTANT LOW STRATUS FIELD.  THE OVERALL COVERAGE PER
LATEST TRENDS DO SUPPORT A TEMPO INCLUSION PRIOR TO MIDNIGHT FROM
FLINT SOUTHWARD.   CEILINGS AT FNT/PTK WILL FLUCTUATE WITHIN IFR/LOW
MVFR THROUGH THIS TIME...LOWER MVFR ELSEWHERE.  DRIER AIR WILL BEGIN
TO ERODE THIS MOIST LAYER FROM ABOVE THROUGH THE EARLY MORNING
PERIOD.  THIS WILL BRING A DIMINISHING TREND TO THE LIGHT
PRECIPITATION COVERAGE...ALTHOUGH THE EXISTING MVFR STRATUS WILL
LIKELY STRUGGLE TO SCATTER UNTIL WELL INTO FRIDAY.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW EARLY TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW THROUGH MIDNIGHT.

&&

.PREV DISCUSSION...ISSUED 355 PM EST THU DEC 18 2014

SHORT TERM...TONIGHT

FREEZING DRIZZLE AND LIGHT SNOW ACROSS SOUTHEAST MICHIGAN IS SLOWLY
BECOMING LESS WIDESPREAD AS THE AFTERNOON PROGRESSES. THE MAIN
CONCERN FOR TONIGHT WILL BE TIMING THE ENDING OF THE FREEZING
DRIZZLE AND WHETHER CLOUDS WILL STICK AROUND. WHILE CURRENT
SATELLITE IMAGERY IS SHOWING DRIER AIR SLOWLY PROGRESSING SOUTHWARD
OUT OF CANADA...PROGRESSION IS REALLY SLOW AND CURRENTLY NOT
ANTICIPATING THE DRY SURGE TO REACH SOUTHEAST MICHIGAN UNTIL CLOSER
TO DAYBREAK FRIDAY MORNING. WITH THE LOW LEVEL MOISTURE STICKING
AROUND OVERNIGHT...LOW LEVEL STRATUS IS EXPECTED TO REMAIN OVER THE
CWA. THE CLOUDS WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH
OVERNIGHT AND HAVE THEREFORE OPTED TO SIDE ON THE WARMER SIDE OF
MODEL GUIDANCE FOR LOWS. EXPECT MID 20S ACROSS THE METRO DETROIT
AREA AND LOW TO MID 20S FOR THE REST OF THE CWA.

IN ADDITION...WHILE DRIZZLE IS DIMINISHING THE FORECASTED STRATUS
COULD RE-INITIATE DRIZZLE FOR THE EARLY PART OF THE EVENING. CURRENT
MODEL SOUNDINGS SHOW A WELL SATURATED BOUNDARY LAYER WITH LIGHT
WINDS OVER SOUTHEAST MICHIGAN THROUGH MOST OF THURSDAY EVENING WHICH
COULD HELP IN THE RE-DEVELOPMENT OF LIGHT DRIZZLE. AS TEMPERATURES
FALL BELOW FREEZING AFTER SUNSET...THE DRIZZLE COULD BECOME FREEZING
DRIZZLE AND MIX WITH SNOW ONCE AGAIN. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOW AT THIS FORECAST ISSUANCE AND HAVE ONLY INCLUDED
FREEZING DRIZZLE IN THE FORECAST THROUGH 00Z /7PM/ THURSDAY. WILL
HAVE TO MONITOR OVER THE NEXT SEVERAL HOURS TO SEE IF DRIZZLE STARTS
TO DEVELOP.

LONG TERM...FRIDAY THROUGH WEDNESDAY

THE UPPER LEVEL PATTERN OVER THE UPPER MIDWEST AND GREAT LAKES
STATES WILL DEAMPLIFY TO THE POINT THAT PSEUDO ZONAL FLOW WILL BE
THE PRIMARY SETUP THROUGH MUCH OF THE UPCOMING WEEKEND. THE MAIN
WESTERLY JET AXIS WILL RESIDE OVER THE SOUTHEASTERN UNITED STATES
WITH VERY NOISY SHORTWAVE ENERGY PASSING WITHIN A FADING MIDLEVEL
COL STRUCTURE. HIGH COLUMN STABILITY SEEMS TO BE THE PRIMARY DRIVER
OF A SURFACE ANTICYCLONE THAT WILL PASS DIRECTLY THROUGH
SOUTHEASTERN MICHIGAN. DEAMPLIFIED FLOW WEAK SHORTWAVE ENERGY AND
RESULTS IN VERY QUIET WEATHER THAT MAINTAINS A STATUS QUO FROM A
TEMPERATURE AND PRECIPITATION PERSPECTIVE.

THERE WILL STILL BE SOME FORECAST DIFFICULTY IN THE EXPECTED
PATTERN...PRIMARILY THAT OF CLOUDS AND CLOUD TRENDS. MODEL DATA IS
VERY AGGRESSIVE WITH A SOUTHWARD PUSH OF DRY AIR LATE
TONIGHT...MAKING INROADS OVER MANY AREAS PRIOR TO SUNRISE. PATTERN
RECOGNITION AND OBSERVATIONAL DATA SUGGESTS OTHERWISE...THE HEAVY
LOOK OF SHEARING OCCURRING ALONG A MIDLEVEL CONVERGENCE BOUNDARY
THAT IS SUPPORTING THE SURFACE TROUGH AND CONTINUATION OF
REFLECTIVITY FINELINE. THE PROBLEM WITH THIS SURFACE TROUGH IS
THAT IT CONTINUES TO HOLD ON STRONGER THAN ANY OF THE MODEL
SOLUTIONS HAVE BEEN SUPPORTING. RH AND SPECIFIC HUMIDITY ANALYSES
SUGGESTS THAT CLEARING MAY BE DOWN TO THE M59 CORRIDOR BY SUNRISE
WITH CLOUDS SOLIDLY LOCKED IN OVER THE CENTRAL DETROIT METRO AREA
SOUTHWARD. THE CLEARING TREND MAY THEN ACCELERATE FOR THESE
SOUTHERN LOCATIONS AS WE HEAD INTO FRIDAY EVENING. FINALLY...COULD
BE LOOKING AT A PERIOD OF CLEAR SKIES FRIDAY NIGHT AND INTO THE
FIRST PART OF SATURDAY. LONGWAVE HEIGHT REBOUND AND WIND DIRECTION
CHANGE TO THE SOUTH BY LATE SATURDAY SUPPORTS THE RETURN OF
ORGANIZED MOISTURE ADVECTION AND CLOUDS.

ACTIVE WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST. THIS
WILL OCCUR AS A STRONG PACIFIC JET ENTERS THE PACIFIC
NORTHWEST...DEEPENS THE LONGWAVE TROUGH OVER THE CENTRAL CONUS...AND
EVENTUALLY CAUSES THE TROUGH TO BECOME NEGATIVELY TILTED AS THE JET
ENERGY ROUNDS THE BASE OF THE TROUGH TOWARD CHRISTMAS EVE. AT THE
SURFACE...A WEAKER LOW PRESSURE SYSTEM WILL EVOLVE OVER THE NORTHERN
PLAINS MONDAY/TUESDAY...EVENTUALLY GETTING ABSORBED BY A POTENTIALLY
STRONGER STORM LIFTING NORTHWARD FROM THE DEEP SOUTH. STILL LOTS OF
POSSIBLE SOLUTIONS AS TO HOW/WHERE THIS INTERACTION TAKES PLACE SO
THE DETAILS ARE FAR FROM BEING CLEAR. AT THIS POINT WILL HIGHLIGHT
THE POTENTIAL FOR IMPACTFUL WEATHER CENTERED AROUND
TUESDAY/WEDNESDAY. IMPACTS IN TERMS OF PRECIPITATION WILL BE MOST
LIKELY DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
MODEL CONSENSUS...WEAK AS IT IS AT THIS POINT...SUGGESTS WE HAVE A
BETTER CHANCE OF BEING ON THE WARMER SIDE OF THIS SYSTEM MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH COLDER AIR AND BREEZY CONDITIONS
BY CHRISTMAS EVE.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT...MAINTAINING
RELATIVELY RELAXED NORTHERLY WINDS FOR THE TIME OF YEAR. THE SURFACE
HIGH IS FORECASTED TO DRIFT ACROSS THE CENTRAL GREAT LAKES THIS
WEEKEND WITH SOUTHERLY FLOW EVENTUALLY RETURNING ON SUNDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....MR
SHORT TERM...RK
LONG TERM....CB/DT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 182341
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
641 PM EST THU DEC 18 2014

.AVIATION...

//DISCUSSION...

DEEP PLUME OF LOW LEVEL MOISTURE TUCKED BENEATH A STRONG INVERSION
WILL HOLD FIRM TONIGHT.  RECENT OBSERVATIONS AND RADAR DATA CONTINUE
TO DISPLAY A COMBINATION OF LIGHT FREEZING DRIZZLE AND SNOWFLAKES
WITHIN THE RESULTANT LOW STRATUS FIELD.  THE OVERALL COVERAGE PER
LATEST TRENDS DO SUPPORT A TEMPO INCLUSION PRIOR TO MIDNIGHT FROM
FLINT SOUTHWARD.   CEILINGS AT FNT/PTK WILL FLUCTUATE WITHIN IFR/LOW
MVFR THROUGH THIS TIME...LOWER MVFR ELSEWHERE.  DRIER AIR WILL BEGIN
TO ERODE THIS MOIST LAYER FROM ABOVE THROUGH THE EARLY MORNING
PERIOD.  THIS WILL BRING A DIMINISHING TREND TO THE LIGHT
PRECIPITATION COVERAGE...ALTHOUGH THE EXISTING MVFR STRATUS WILL
LIKELY STRUGGLE TO SCATTER UNTIL WELL INTO FRIDAY.

FOR DTW...THERE WILL CONTINUE TO BE THE POTENTIAL FOR A LIGHT
MIXTURE OF FREEZING DRIZZLE AND SNOW EARLY TONIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE CEILINGS REMAIN BELOW 5000 FT THROUGH FRIDAY
  MORNING.

* HIGH CONFIDENCE THAT PRECIPITATION TYPE WILL BE A MIXTURE OF LIGHT
  FREEZING DRIZZLE AND SNOW THROUGH MIDNIGHT.

&&

.PREV DISCUSSION...ISSUED 355 PM EST THU DEC 18 2014

SHORT TERM...TONIGHT

FREEZING DRIZZLE AND LIGHT SNOW ACROSS SOUTHEAST MICHIGAN IS SLOWLY
BECOMING LESS WIDESPREAD AS THE AFTERNOON PROGRESSES. THE MAIN
CONCERN FOR TONIGHT WILL BE TIMING THE ENDING OF THE FREEZING
DRIZZLE AND WHETHER CLOUDS WILL STICK AROUND. WHILE CURRENT
SATELLITE IMAGERY IS SHOWING DRIER AIR SLOWLY PROGRESSING SOUTHWARD
OUT OF CANADA...PROGRESSION IS REALLY SLOW AND CURRENTLY NOT
ANTICIPATING THE DRY SURGE TO REACH SOUTHEAST MICHIGAN UNTIL CLOSER
TO DAYBREAK FRIDAY MORNING. WITH THE LOW LEVEL MOISTURE STICKING
AROUND OVERNIGHT...LOW LEVEL STRATUS IS EXPECTED TO REMAIN OVER THE
CWA. THE CLOUDS WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH
OVERNIGHT AND HAVE THEREFORE OPTED TO SIDE ON THE WARMER SIDE OF
MODEL GUIDANCE FOR LOWS. EXPECT MID 20S ACROSS THE METRO DETROIT
AREA AND LOW TO MID 20S FOR THE REST OF THE CWA.

IN ADDITION...WHILE DRIZZLE IS DIMINISHING THE FORECASTED STRATUS
COULD RE-INITIATE DRIZZLE FOR THE EARLY PART OF THE EVENING. CURRENT
MODEL SOUNDINGS SHOW A WELL SATURATED BOUNDARY LAYER WITH LIGHT
WINDS OVER SOUTHEAST MICHIGAN THROUGH MOST OF THURSDAY EVENING WHICH
COULD HELP IN THE RE-DEVELOPMENT OF LIGHT DRIZZLE. AS TEMPERATURES
FALL BELOW FREEZING AFTER SUNSET...THE DRIZZLE COULD BECOME FREEZING
DRIZZLE AND MIX WITH SNOW ONCE AGAIN. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOW AT THIS FORECAST ISSUANCE AND HAVE ONLY INCLUDED
FREEZING DRIZZLE IN THE FORECAST THROUGH 00Z /7PM/ THURSDAY. WILL
HAVE TO MONITOR OVER THE NEXT SEVERAL HOURS TO SEE IF DRIZZLE STARTS
TO DEVELOP.

LONG TERM...FRIDAY THROUGH WEDNESDAY

THE UPPER LEVEL PATTERN OVER THE UPPER MIDWEST AND GREAT LAKES
STATES WILL DEAMPLIFY TO THE POINT THAT PSEUDO ZONAL FLOW WILL BE
THE PRIMARY SETUP THROUGH MUCH OF THE UPCOMING WEEKEND. THE MAIN
WESTERLY JET AXIS WILL RESIDE OVER THE SOUTHEASTERN UNITED STATES
WITH VERY NOISY SHORTWAVE ENERGY PASSING WITHIN A FADING MIDLEVEL
COL STRUCTURE. HIGH COLUMN STABILITY SEEMS TO BE THE PRIMARY DRIVER
OF A SURFACE ANTICYCLONE THAT WILL PASS DIRECTLY THROUGH
SOUTHEASTERN MICHIGAN. DEAMPLIFIED FLOW WEAK SHORTWAVE ENERGY AND
RESULTS IN VERY QUIET WEATHER THAT MAINTAINS A STATUS QUO FROM A
TEMPERATURE AND PRECIPITATION PERSPECTIVE.

THERE WILL STILL BE SOME FORECAST DIFFICULTY IN THE EXPECTED
PATTERN...PRIMARILY THAT OF CLOUDS AND CLOUD TRENDS. MODEL DATA IS
VERY AGGRESSIVE WITH A SOUTHWARD PUSH OF DRY AIR LATE
TONIGHT...MAKING INROADS OVER MANY AREAS PRIOR TO SUNRISE. PATTERN
RECOGNITION AND OBSERVATIONAL DATA SUGGESTS OTHERWISE...THE HEAVY
LOOK OF SHEARING OCCURRING ALONG A MIDLEVEL CONVERGENCE BOUNDARY
THAT IS SUPPORTING THE SURFACE TROUGH AND CONTINUATION OF
REFLECTIVITY FINELINE. THE PROBLEM WITH THIS SURFACE TROUGH IS
THAT IT CONTINUES TO HOLD ON STRONGER THAN ANY OF THE MODEL
SOLUTIONS HAVE BEEN SUPPORTING. RH AND SPECIFIC HUMIDITY ANALYSES
SUGGESTS THAT CLEARING MAY BE DOWN TO THE M59 CORRIDOR BY SUNRISE
WITH CLOUDS SOLIDLY LOCKED IN OVER THE CENTRAL DETROIT METRO AREA
SOUTHWARD. THE CLEARING TREND MAY THEN ACCELERATE FOR THESE
SOUTHERN LOCATIONS AS WE HEAD INTO FRIDAY EVENING. FINALLY...COULD
BE LOOKING AT A PERIOD OF CLEAR SKIES FRIDAY NIGHT AND INTO THE
FIRST PART OF SATURDAY. LONGWAVE HEIGHT REBOUND AND WIND DIRECTION
CHANGE TO THE SOUTH BY LATE SATURDAY SUPPORTS THE RETURN OF
ORGANIZED MOISTURE ADVECTION AND CLOUDS.

ACTIVE WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST. THIS
WILL OCCUR AS A STRONG PACIFIC JET ENTERS THE PACIFIC
NORTHWEST...DEEPENS THE LONGWAVE TROUGH OVER THE CENTRAL CONUS...AND
EVENTUALLY CAUSES THE TROUGH TO BECOME NEGATIVELY TILTED AS THE JET
ENERGY ROUNDS THE BASE OF THE TROUGH TOWARD CHRISTMAS EVE. AT THE
SURFACE...A WEAKER LOW PRESSURE SYSTEM WILL EVOLVE OVER THE NORTHERN
PLAINS MONDAY/TUESDAY...EVENTUALLY GETTING ABSORBED BY A POTENTIALLY
STRONGER STORM LIFTING NORTHWARD FROM THE DEEP SOUTH. STILL LOTS OF
POSSIBLE SOLUTIONS AS TO HOW/WHERE THIS INTERACTION TAKES PLACE SO
THE DETAILS ARE FAR FROM BEING CLEAR. AT THIS POINT WILL HIGHLIGHT
THE POTENTIAL FOR IMPACTFUL WEATHER CENTERED AROUND
TUESDAY/WEDNESDAY. IMPACTS IN TERMS OF PRECIPITATION WILL BE MOST
LIKELY DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
MODEL CONSENSUS...WEAK AS IT IS AT THIS POINT...SUGGESTS WE HAVE A
BETTER CHANCE OF BEING ON THE WARMER SIDE OF THIS SYSTEM MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH COLDER AIR AND BREEZY CONDITIONS
BY CHRISTMAS EVE.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT...MAINTAINING
RELATIVELY RELAXED NORTHERLY WINDS FOR THE TIME OF YEAR. THE SURFACE
HIGH IS FORECASTED TO DRIFT ACROSS THE CENTRAL GREAT LAKES THIS
WEEKEND WITH SOUTHERLY FLOW EVENTUALLY RETURNING ON SUNDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....MR
SHORT TERM...RK
LONG TERM....CB/DT
MARINE.......CB


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 182055
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
355 PM EST THU DEC 18 2014

.SHORT TERM...TONIGHT

FREEZING DRIZZLE AND LIGHT SNOW ACROSS SOUTHEAST MICHIGAN IS SLOWLY
BECOMING LESS WIDESPREAD AS THE AFTERNOON PROGRESSES. THE MAIN
CONCERN FOR TONIGHT WILL BE TIMING THE ENDING OF THE FREEZING
DRIZZLE AND WHETHER CLOUDS WILL STICK AROUND. WHILE CURRENT
SATELLITE IMAGERY IS SHOWING DRIER AIR SLOWLY PROGRESSING SOUTHWARD
OUT OF CANADA...PROGRESSION IS REALLY SLOW AND CURRENTLY NOT
ANTICIPATING THE DRY SURGE TO REACH SOUTHEAST MICHIGAN UNTIL CLOSER
TO DAYBREAK FRIDAY MORNING. WITH THE LOW LEVEL MOISTURE STICKING
AROUND OVERNIGHT...LOW LEVEL STRATUS IS EXPECTED TO REMAIN OVER THE
CWA. THE CLOUDS WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH
OVERNIGHT AND HAVE THEREFORE OPTED TO SIDE ON THE WARMER SIDE OF
MODEL GUIDANCE FOR LOWS. EXPECT MID 20S ACROSS THE METRO DETROIT
AREA AND LOW TO MID 20S FOR THE REST OF THE CWA.

IN ADDITION...WHILE DRIZZLE IS DIMINISHING THE FORECASTED STRATUS
COULD RE-INITIATE DRIZZLE FOR THE EARLY PART OF THE EVENING. CURRENT
MODEL SOUNDINGS SHOW A WELL SATURATED BOUNDARY LAYER WITH LIGHT
WINDS OVER SOUTHEAST MICHIGAN THROUGH MOST OF THURSDAY EVENING WHICH
COULD HELP IN THE RE-DEVELOPMENT OF LIGHT DRIZZLE. AS TEMPERATURES
FALL BELOW FREEZING AFTER SUNSET...THE DRIZZLE COULD BECOME FREEZING
DRIZZLE AND MIX WITH SNOW ONCE AGAIN. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOW AT THIS FORECAST ISSUANCE AND HAVE ONLY INCLUDED
FREEZING DRIZZLE IN THE FORECAST THROUGH 00Z /7PM/ THURSDAY. WILL
HAVE TO MONITOR OVER THE NEXT SEVERAL HOURS TO SEE IF DRIZZLE STARTS
TO DEVELOP.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY

THE UPPER LEVEL PATTERN OVER THE UPPER MIDWEST AND GREAT LAKES
STATES WILL DEAMPLIFY TO THE POINT THAT PSEUDO ZONAL FLOW WILL BE
THE PRIMARY SETUP THROUGH MUCH OF THE UPCOMING WEEKEND. THE MAIN
WESTERLY JET AXIS WILL RESIDE OVER THE SOUTHEASTERN UNITED STATES
WITH VERY NOISY SHORTWAVE ENERGY PASSING WITHIN A FADING MIDLEVEL
COL STRUCTURE. HIGH COLUMN STABILITY SEEMS TO BE THE PRIMARY DRIVER
OF A SURFACE ANTICYCLONE THAT WILL PASS DIRECTLY THROUGH
SOUTHEASTERN MICHIGAN. DEAMPLIFIED FLOW WEAK SHORTWAVE ENERGY AND
RESULTS IN VERY QUIET WEATHER THAT MAINTAINS A STATUS QUO FROM A
TEMPERATURE AND PRECIPITATION PERSPECTIVE.

THERE WILL STILL BE SOME FORECAST DIFFICULTY IN THE EXPECTED
PATTERN...PRIMARILY THAT OF CLOUDS AND CLOUD TRENDS. MODEL DATA IS
VERY AGGRESSIVE WITH A SOUTHWARD PUSH OF DRY AIR LATE
TONIGHT...MAKING INROADS OVER MANY AREAS PRIOR TO SUNRISE. PATTERN
RECOGNITION AND OBSERVATIONAL DATA SUGGESTS OTHERWISE...THE HEAVY
LOOK OF SHEARING OCCURRING ALONG A MIDLEVEL CONVERGENCE BOUNDARY
THAT IS SUPPORTING THE SURFACE TROUGH AND CONTINUATION OF
REFLECTIVITY FINELINE. THE PROBLEM WITH THIS SURFACE TROUGH IS
THAT IT CONTINUES TO HOLD ON STRONGER THAN ANY OF THE MODEL
SOLUTIONS HAVE BEEN SUPPORTING. RH AND SPECIFIC HUMIDITY ANALYSES
SUGGESTS THAT CLEARING MAY BE DOWN TO THE M59 CORRIDOR BY SUNRISE
WITH CLOUDS SOLIDLY LOCKED IN OVER THE CENTRAL DETROIT METRO AREA
SOUTHWARD. THE CLEARING TREND MAY THEN ACCELERATE FOR THESE
SOUTHERN LOCATIONS AS WE HEAD INTO FRIDAY EVENING. FINALLY...COULD
BE LOOKING AT A PERIOD OF CLEAR SKIES FRIDAY NIGHT AND INTO THE
FIRST PART OF SATURDAY. LONGWAVE HEIGHT REBOUND AND WIND DIRECTION
CHANGE TO THE SOUTH BY LATE SATURDAY SUPPORTS THE RETURN OF
ORGANIZED MOISTURE ADVECTION AND CLOUDS.

ACTIVE WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST. THIS
WILL OCCUR AS A STRONG PACIFIC JET ENTERS THE PACIFIC
NORTHWEST...DEEPENS THE LONGWAVE TROUGH OVER THE CENTRAL CONUS...AND
EVENTUALLY CAUSES THE TROUGH TO BECOME NEGATIVELY TILTED AS THE JET
ENERGY ROUNDS THE BASE OF THE TROUGH TOWARD CHRISTMAS EVE. AT THE
SURFACE...A WEAKER LOW PRESSURE SYSTEM WILL EVOLVE OVER THE NORTHERN
PLAINS MONDAY/TUESDAY...EVENTUALLY GETTING ABSORBED BY A POTENTIALLY
STRONGER STORM LIFTING NORTHWARD FROM THE DEEP SOUTH. STILL LOTS OF
POSSIBLE SOLUTIONS AS TO HOW/WHERE THIS INTERACTION TAKES PLACE SO
THE DETAILS ARE FAR FROM BEING CLEAR. AT THIS POINT WILL HIGHLIGHT
THE POTENTIAL FOR IMPACTFUL WEATHER CENTERED AROUND
TUESDAY/WEDNESDAY. IMPACTS IN TERMS OF PRECIPITATION WILL BE MOST
LIKELY DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
MODEL CONSENSUS...WEAK AS IT IS AT THIS POINT...SUGGESTS WE HAVE A
BETTER CHANCE OF BEING ON THE WARMER SIDE OF THIS SYSTEM MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH COLDER AIR AND BREEZY CONDITIONS
BY CHRISTMAS EVE.

&&

.MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT...MAINTAINING
RELATIVELY RELAXED NORTHERLY WINDS FOR THE TIME OF YEAR. THE SURFACE
HIGH IS FORECASTED TO DRIFT ACROSS THE CENTRAL GREAT LAKES THIS
WEEKEND WITH SOUTHERLY FLOW EVENTUALLY RETURNING ON SUNDAY.

&&

.AVIATION...ISSUED 1227 PM EST THU DEC 18 2014

//DISCUSSION...

LIGHT FREEZING DRIZZLE/SNOW WILL BE POSSIBLE THROUGH EARLY AFTERNOON
AT MOST OF THE TAF SITES. FREEZING DRIZZLE AS WELL AS SOME LIGHT FOG
WILL CAUSE REDUCTIONS IN VISIBILITIES ACROSS SOUTHEAST MICHIGAN. A
NORTHERLY WIND SHIFT COMBINED WITH DRIER AIR FILTERING INTO THE
REGION LATE THIS AFTERNOON WILL DRIVE OUT ANY LINGERING FREEZING
DRIZZLE HOWEVER...EXPECTING STRATUS TO STICK AROUND THROUGH THE
OVERNIGHT PERIOD. CLOUDS FOR THE MOST PART WILL STICK AROUND THROUGH
FRIDAY MORNING BEFORE SLOWLY SCATTERING OUT FIRST IN THE NORTH AND
EVENTUALLY IN THE SOUTH BY FRIDAY AFTERNOON.

FOR DTW... AREAS OF FREEZING DRIZZLE MIXED WITH SOME LIGHT SNOW WILL
BE POSSIBLE THROUGH THE FIRST HALF OF THE AFTERNOON. FREEZING
DRIZZLE IS ANTICIPATED TO COME TO AN END BY 23Z. OVERCAST MVFR
CEILINGS WILL REMAIN OVER DTW THROUGH THE OVERNIGHT HOURS AND INTO
FRIDAY MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE THAT CEILINGS WILL REMAIN BELOW 5000 FT 12Z
  FRIDAY. MODERATE CONFIDENCE THAT CEILINGS WILL ALSO BE BELOW 5000
  FT BETWEEN 12Z AND 18Z FRIDAY.

* HIGH CONFIDENCE THAT PRECIP TYPE WILL BE LIGHT FREEZING
  DRIZZLE/SNOW THROUGH 21Z THURSDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

SHORT TERM...RK
LONG TERM....CB/DT
MARINE.......CB
AVIATION.....RK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 182055
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
355 PM EST THU DEC 18 2014

.SHORT TERM...TONIGHT

FREEZING DRIZZLE AND LIGHT SNOW ACROSS SOUTHEAST MICHIGAN IS SLOWLY
BECOMING LESS WIDESPREAD AS THE AFTERNOON PROGRESSES. THE MAIN
CONCERN FOR TONIGHT WILL BE TIMING THE ENDING OF THE FREEZING
DRIZZLE AND WHETHER CLOUDS WILL STICK AROUND. WHILE CURRENT
SATELLITE IMAGERY IS SHOWING DRIER AIR SLOWLY PROGRESSING SOUTHWARD
OUT OF CANADA...PROGRESSION IS REALLY SLOW AND CURRENTLY NOT
ANTICIPATING THE DRY SURGE TO REACH SOUTHEAST MICHIGAN UNTIL CLOSER
TO DAYBREAK FRIDAY MORNING. WITH THE LOW LEVEL MOISTURE STICKING
AROUND OVERNIGHT...LOW LEVEL STRATUS IS EXPECTED TO REMAIN OVER THE
CWA. THE CLOUDS WILL KEEP TEMPERATURES FROM DROPPING TOO MUCH
OVERNIGHT AND HAVE THEREFORE OPTED TO SIDE ON THE WARMER SIDE OF
MODEL GUIDANCE FOR LOWS. EXPECT MID 20S ACROSS THE METRO DETROIT
AREA AND LOW TO MID 20S FOR THE REST OF THE CWA.

IN ADDITION...WHILE DRIZZLE IS DIMINISHING THE FORECASTED STRATUS
COULD RE-INITIATE DRIZZLE FOR THE EARLY PART OF THE EVENING. CURRENT
MODEL SOUNDINGS SHOW A WELL SATURATED BOUNDARY LAYER WITH LIGHT
WINDS OVER SOUTHEAST MICHIGAN THROUGH MOST OF THURSDAY EVENING WHICH
COULD HELP IN THE RE-DEVELOPMENT OF LIGHT DRIZZLE. AS TEMPERATURES
FALL BELOW FREEZING AFTER SUNSET...THE DRIZZLE COULD BECOME FREEZING
DRIZZLE AND MIX WITH SNOW ONCE AGAIN. HOWEVER...CONFIDENCE IN THIS
OCCURRING IS LOW AT THIS FORECAST ISSUANCE AND HAVE ONLY INCLUDED
FREEZING DRIZZLE IN THE FORECAST THROUGH 00Z /7PM/ THURSDAY. WILL
HAVE TO MONITOR OVER THE NEXT SEVERAL HOURS TO SEE IF DRIZZLE STARTS
TO DEVELOP.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY

THE UPPER LEVEL PATTERN OVER THE UPPER MIDWEST AND GREAT LAKES
STATES WILL DEAMPLIFY TO THE POINT THAT PSEUDO ZONAL FLOW WILL BE
THE PRIMARY SETUP THROUGH MUCH OF THE UPCOMING WEEKEND. THE MAIN
WESTERLY JET AXIS WILL RESIDE OVER THE SOUTHEASTERN UNITED STATES
WITH VERY NOISY SHORTWAVE ENERGY PASSING WITHIN A FADING MIDLEVEL
COL STRUCTURE. HIGH COLUMN STABILITY SEEMS TO BE THE PRIMARY DRIVER
OF A SURFACE ANTICYCLONE THAT WILL PASS DIRECTLY THROUGH
SOUTHEASTERN MICHIGAN. DEAMPLIFIED FLOW WEAK SHORTWAVE ENERGY AND
RESULTS IN VERY QUIET WEATHER THAT MAINTAINS A STATUS QUO FROM A
TEMPERATURE AND PRECIPITATION PERSPECTIVE.

THERE WILL STILL BE SOME FORECAST DIFFICULTY IN THE EXPECTED
PATTERN...PRIMARILY THAT OF CLOUDS AND CLOUD TRENDS. MODEL DATA IS
VERY AGGRESSIVE WITH A SOUTHWARD PUSH OF DRY AIR LATE
TONIGHT...MAKING INROADS OVER MANY AREAS PRIOR TO SUNRISE. PATTERN
RECOGNITION AND OBSERVATIONAL DATA SUGGESTS OTHERWISE...THE HEAVY
LOOK OF SHEARING OCCURRING ALONG A MIDLEVEL CONVERGENCE BOUNDARY
THAT IS SUPPORTING THE SURFACE TROUGH AND CONTINUATION OF
REFLECTIVITY FINELINE. THE PROBLEM WITH THIS SURFACE TROUGH IS
THAT IT CONTINUES TO HOLD ON STRONGER THAN ANY OF THE MODEL
SOLUTIONS HAVE BEEN SUPPORTING. RH AND SPECIFIC HUMIDITY ANALYSES
SUGGESTS THAT CLEARING MAY BE DOWN TO THE M59 CORRIDOR BY SUNRISE
WITH CLOUDS SOLIDLY LOCKED IN OVER THE CENTRAL DETROIT METRO AREA
SOUTHWARD. THE CLEARING TREND MAY THEN ACCELERATE FOR THESE
SOUTHERN LOCATIONS AS WE HEAD INTO FRIDAY EVENING. FINALLY...COULD
BE LOOKING AT A PERIOD OF CLEAR SKIES FRIDAY NIGHT AND INTO THE
FIRST PART OF SATURDAY. LONGWAVE HEIGHT REBOUND AND WIND DIRECTION
CHANGE TO THE SOUTH BY LATE SATURDAY SUPPORTS THE RETURN OF
ORGANIZED MOISTURE ADVECTION AND CLOUDS.

ACTIVE WEATHER IS EXPECTED FOR THE REMAINDER OF THE FORECAST. THIS
WILL OCCUR AS A STRONG PACIFIC JET ENTERS THE PACIFIC
NORTHWEST...DEEPENS THE LONGWAVE TROUGH OVER THE CENTRAL CONUS...AND
EVENTUALLY CAUSES THE TROUGH TO BECOME NEGATIVELY TILTED AS THE JET
ENERGY ROUNDS THE BASE OF THE TROUGH TOWARD CHRISTMAS EVE. AT THE
SURFACE...A WEAKER LOW PRESSURE SYSTEM WILL EVOLVE OVER THE NORTHERN
PLAINS MONDAY/TUESDAY...EVENTUALLY GETTING ABSORBED BY A POTENTIALLY
STRONGER STORM LIFTING NORTHWARD FROM THE DEEP SOUTH. STILL LOTS OF
POSSIBLE SOLUTIONS AS TO HOW/WHERE THIS INTERACTION TAKES PLACE SO
THE DETAILS ARE FAR FROM BEING CLEAR. AT THIS POINT WILL HIGHLIGHT
THE POTENTIAL FOR IMPACTFUL WEATHER CENTERED AROUND
TUESDAY/WEDNESDAY. IMPACTS IN TERMS OF PRECIPITATION WILL BE MOST
LIKELY DURING THE MONDAY NIGHT THROUGH WEDNESDAY TIME FRAME.
MODEL CONSENSUS...WEAK AS IT IS AT THIS POINT...SUGGESTS WE HAVE A
BETTER CHANCE OF BEING ON THE WARMER SIDE OF THIS SYSTEM MONDAY
NIGHT THROUGH TUESDAY NIGHT...WITH COLDER AIR AND BREEZY CONDITIONS
BY CHRISTMAS EVE.

&&

.MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TONIGHT...MAINTAINING
RELATIVELY RELAXED NORTHERLY WINDS FOR THE TIME OF YEAR. THE SURFACE
HIGH IS FORECASTED TO DRIFT ACROSS THE CENTRAL GREAT LAKES THIS
WEEKEND WITH SOUTHERLY FLOW EVENTUALLY RETURNING ON SUNDAY.

&&

.AVIATION...ISSUED 1227 PM EST THU DEC 18 2014

//DISCUSSION...

LIGHT FREEZING DRIZZLE/SNOW WILL BE POSSIBLE THROUGH EARLY AFTERNOON
AT MOST OF THE TAF SITES. FREEZING DRIZZLE AS WELL AS SOME LIGHT FOG
WILL CAUSE REDUCTIONS IN VISIBILITIES ACROSS SOUTHEAST MICHIGAN. A
NORTHERLY WIND SHIFT COMBINED WITH DRIER AIR FILTERING INTO THE
REGION LATE THIS AFTERNOON WILL DRIVE OUT ANY LINGERING FREEZING
DRIZZLE HOWEVER...EXPECTING STRATUS TO STICK AROUND THROUGH THE
OVERNIGHT PERIOD. CLOUDS FOR THE MOST PART WILL STICK AROUND THROUGH
FRIDAY MORNING BEFORE SLOWLY SCATTERING OUT FIRST IN THE NORTH AND
EVENTUALLY IN THE SOUTH BY FRIDAY AFTERNOON.

FOR DTW... AREAS OF FREEZING DRIZZLE MIXED WITH SOME LIGHT SNOW WILL
BE POSSIBLE THROUGH THE FIRST HALF OF THE AFTERNOON. FREEZING
DRIZZLE IS ANTICIPATED TO COME TO AN END BY 23Z. OVERCAST MVFR
CEILINGS WILL REMAIN OVER DTW THROUGH THE OVERNIGHT HOURS AND INTO
FRIDAY MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE THAT CEILINGS WILL REMAIN BELOW 5000 FT 12Z
  FRIDAY. MODERATE CONFIDENCE THAT CEILINGS WILL ALSO BE BELOW 5000
  FT BETWEEN 12Z AND 18Z FRIDAY.

* HIGH CONFIDENCE THAT PRECIP TYPE WILL BE LIGHT FREEZING
  DRIZZLE/SNOW THROUGH 21Z THURSDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

SHORT TERM...RK
LONG TERM....CB/DT
MARINE.......CB
AVIATION.....RK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 181727
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1227 PM EST THU DEC 18 2014


.AVIATION...

//DISCUSSION...

LIGHT FREEZING DRIZZLE/SNOW WILL BE POSSIBLE THROUGH EARLY AFTERNOON
AT MOST OF THE TAF SITES. FREEZING DRIZZLE AS WELL AS SOME LIGHT FOG
WILL CAUSE REDUCTIONS IN VISIBILITIES ACROSS SOUTHEAST MICHIGAN. A
NORTHERLY WIND SHIFT COMBINED WITH DRIER AIR FILTERING INTO THE
REGION LATE THIS AFTERNOON WILL DRIVE OUT ANY LINGERING FREEZING
DRIZZLE HOWEVER...EXPECTING STRATUS TO STICK AROUND THROUGH THE
OVERNIGHT PERIOD. CLOUDS FOR THE MOST PART WILL STICK AROUND THROUGH
FRIDAY MORNING BEFORE SLOWLY SCATTERING OUT FIRST IN THE NORTH AND
EVENTUALLY IN THE SOUTH BY FRIDAY AFTERNOON.

FOR DTW... AREAS OF FREEZING DRIZZLE MIXED WITH SOME LIGHT SNOW WILL
BE POSSIBLE THROUGH THE FIRST HALF OF THE AFTERNOON. FREEZING
DRIZZLE IS ANTICIPATED TO COME TO AN END BY 23Z. OVERCAST MVFR
CEILINGS WILL REMAIN OVER DTW THROUGH THE OVERNIGHT HOURS AND INTO
FRIDAY MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE THAT CEILINGS WILL REMAIN BELOW 5000 FT 12Z
  FRIDAY. MODERATE CONFIDENCE THAT CEILINGS WILL ALSO BE BELOW 5000
  FT BETWEEN 12Z AND 18Z FRIDAY.

* HIGH CONFIDENCE THAT PRECIP TYPE WILL BE LIGHT FREEZING
  DRIZZLE/SNOW THROUGH 21Z THURSDAY.

&&

.PREV DISCUSSION...ISSUED 1128 AM EST THU DEC 18 2014

UPDATE...

AREAS OF PATCHY FREEZING DRIZZLE WILL CONTINUE TO IMPACT SOUTHEAST
MICHIGAN THROUGH EARLY AFTERNOON. CURRENT RADAR IMAGERY AND LOCAL
OBSERVATIONS ARE SHOWING FREEZING DRIZZLE FILTERING INTO
SOUTHEAST MICHIGAN. PLENTY OF MOISTURE IN THE BOUNDARY LAYER AND
SURFACE TEMPERATURES HOVERING NEAR FREEZING WILL RESULT IN
FREEZING DRIZZLE CONTINUING INTO THE AFTERNOON HOURS. LOCATIONS
MOST LIKELY TO SEE FREEZING DRIZZLE WILL BE BETWEEN THE I 69 AND I
94 CORRIDOR. MOTORISTS SHOULD BE ADVISED IF TRAVELING IN SOUTHEAST
MICHIGAN AS LIGHT ICING ON ROADWAYS COULD LEAD TO SLIPPERY
CONDITIONS MAINLY ON BRIDGES...OVERPASSES...AND EXIT RAMPS. DRIER
AIR WILL BEGIN TO FILTER INTO THE REGION BY LATE
AFTERNOON...CAUSING FREEZING DRIZZLE TO COME TO AN END.

PREV DISCUSSION...ISSUED 347 AM EST THU DEC 18 2014

SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENSIS OVER THE WESTERN GREAT LAKES ON
TUESDAY AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT
UPPER LEVEL JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS
HEIGHTS FALL. THE AREA LOOKS TO BE IN THE WARM SECTOR DURING THE
FIRST PART OF THIS EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A
STRONG PUSH OF COLD AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO
ALL SNOW BY CHRISTMAS EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....RK
UPDATE.......RK
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 181727
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1227 PM EST THU DEC 18 2014


.AVIATION...

//DISCUSSION...

LIGHT FREEZING DRIZZLE/SNOW WILL BE POSSIBLE THROUGH EARLY AFTERNOON
AT MOST OF THE TAF SITES. FREEZING DRIZZLE AS WELL AS SOME LIGHT FOG
WILL CAUSE REDUCTIONS IN VISIBILITIES ACROSS SOUTHEAST MICHIGAN. A
NORTHERLY WIND SHIFT COMBINED WITH DRIER AIR FILTERING INTO THE
REGION LATE THIS AFTERNOON WILL DRIVE OUT ANY LINGERING FREEZING
DRIZZLE HOWEVER...EXPECTING STRATUS TO STICK AROUND THROUGH THE
OVERNIGHT PERIOD. CLOUDS FOR THE MOST PART WILL STICK AROUND THROUGH
FRIDAY MORNING BEFORE SLOWLY SCATTERING OUT FIRST IN THE NORTH AND
EVENTUALLY IN THE SOUTH BY FRIDAY AFTERNOON.

FOR DTW... AREAS OF FREEZING DRIZZLE MIXED WITH SOME LIGHT SNOW WILL
BE POSSIBLE THROUGH THE FIRST HALF OF THE AFTERNOON. FREEZING
DRIZZLE IS ANTICIPATED TO COME TO AN END BY 23Z. OVERCAST MVFR
CEILINGS WILL REMAIN OVER DTW THROUGH THE OVERNIGHT HOURS AND INTO
FRIDAY MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE THAT CEILINGS WILL REMAIN BELOW 5000 FT 12Z
  FRIDAY. MODERATE CONFIDENCE THAT CEILINGS WILL ALSO BE BELOW 5000
  FT BETWEEN 12Z AND 18Z FRIDAY.

* HIGH CONFIDENCE THAT PRECIP TYPE WILL BE LIGHT FREEZING
  DRIZZLE/SNOW THROUGH 21Z THURSDAY.

&&

.PREV DISCUSSION...ISSUED 1128 AM EST THU DEC 18 2014

UPDATE...

AREAS OF PATCHY FREEZING DRIZZLE WILL CONTINUE TO IMPACT SOUTHEAST
MICHIGAN THROUGH EARLY AFTERNOON. CURRENT RADAR IMAGERY AND LOCAL
OBSERVATIONS ARE SHOWING FREEZING DRIZZLE FILTERING INTO
SOUTHEAST MICHIGAN. PLENTY OF MOISTURE IN THE BOUNDARY LAYER AND
SURFACE TEMPERATURES HOVERING NEAR FREEZING WILL RESULT IN
FREEZING DRIZZLE CONTINUING INTO THE AFTERNOON HOURS. LOCATIONS
MOST LIKELY TO SEE FREEZING DRIZZLE WILL BE BETWEEN THE I 69 AND I
94 CORRIDOR. MOTORISTS SHOULD BE ADVISED IF TRAVELING IN SOUTHEAST
MICHIGAN AS LIGHT ICING ON ROADWAYS COULD LEAD TO SLIPPERY
CONDITIONS MAINLY ON BRIDGES...OVERPASSES...AND EXIT RAMPS. DRIER
AIR WILL BEGIN TO FILTER INTO THE REGION BY LATE
AFTERNOON...CAUSING FREEZING DRIZZLE TO COME TO AN END.

PREV DISCUSSION...ISSUED 347 AM EST THU DEC 18 2014

SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENSIS OVER THE WESTERN GREAT LAKES ON
TUESDAY AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT
UPPER LEVEL JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS
HEIGHTS FALL. THE AREA LOOKS TO BE IN THE WARM SECTOR DURING THE
FIRST PART OF THIS EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A
STRONG PUSH OF COLD AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO
ALL SNOW BY CHRISTMAS EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....RK
UPDATE.......RK
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 181628
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1128 AM EST THU DEC 18 2014

.UPDATE...

AREAS OF PATCHY FREEZING DRIZZLE WILL CONTINUE TO IMPACT SOUTHEAST
MICHIGAN THROUGH EARLY AFTERNOON. CURRENT RADAR IMAGERY AND LOCAL
OBSERVATIONS ARE SHOWING FREEZING DRIZZLE FILTERING INTO
SOUTHEAST MICHIGAN. PLENTY OF MOISTURE IN THE BOUNDARY LAYER AND
SURFACE TEMPERATURES HOVERING NEAR FREEZING WILL RESULT IN
FREEZING DRIZZLE CONTINUING INTO THE AFTERNOON HOURS. LOCATIONS
MOST LIKELY TO SEE FREEZING DRIZZLE WILL BE BETWEEN THE I 69 AND I
94 CORRIDOR. MOTORISTS SHOULD BE ADVISED IF TRAVELING IN SOUTHEAST
MICHIGAN AS LIGHT ICING ON ROADWAYS COULD LEAD TO SLIPPERY
CONDITIONS MAINLY ON BRIDGES...OVERPASSES...AND EXIT RAMPS. DRIER
AIR WILL BEGIN TO FILTER INTO THE REGION BY LATE
AFTERNOON...CAUSING FREEZING DRIZZLE TO COME TO AN END.

&&

.AVIATION...ISSUED 653 AM EST THU DEC 18 2014

//DISCUSSION...

A WEAKENING SURFACE TROUGH OF LOW PRESSURE WILL SETTLE SLOWLY OVER
SE MICHIGAN DURING THE DAY AND MAINTAIN MVFR CEILING AT ALL TERMINAL
SITES. A FEW POCKETS OF SNOW GRAINS OR VERY LIGHT DRIZZLE/FZDZ WILL
BE POSSIBLE BUT VERY TRANSIENT DURING THE MORNING. THIS WILL BE
MONITORED FOR POTENTIAL UPDATES IF ANY OBSERVATIONS SUGGEST A
VISIBILITY RESTRICTION...WHICH WOULD INDICATE MORE SUBSTANTIAL
ACTIVITY. OTHERWISE...MVFR STRATUS WILL LINGER THROUGH MIDNIGHT
FOLLOWED BY DRY AIR AND LESS CLOUDS TOWARD SUNRISE AS THE TROUGH
WEAKENS AND THE WIND TURNS MORE FROM THE NORTH.

FOR DTW... MVFR CEILING WILL BE FIRMLY IN PLACE THROUGH THE DAY WITH
PRECIPITATION LIMITED TO VERY LIGHT AND BRIEF SNOW GRAINS OR
DRIZZLE/FZDZ DURING THE MORNING. NO OPERATIONAL IMPACT IS EXPECTED
AND THE POTENTIAL WILL DIMINISH AS THE TROUGH WEAKENS DURING THE
MORNING. THIS WILL NOT BE CARRIED IN THE FORECAST BUT WILL BE
MONITORED FOR SIGNS OF INCREASED ACTIVITY. MVFR CLOUDS WILL LINGER
THROUGH THE NIGHT AND THEN DIMINISH FROM NORTH TO SOUTH AFTER
SUNRISE FRIDAY.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY THROUGH TONIGHT.

&&

.PREV DISCUSSION...ISSUED 347 AM EST THU DEC 18 2014

SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENSIS OVER THE WESTERN GREAT LAKES ON
TUESDAY AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT
UPPER LEVEL JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS
HEIGHTS FALL. THE AREA LOOKS TO BE IN THE WARM SECTOR DURING THE
FIRST PART OF THIS EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A
STRONG PUSH OF COLD AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO
ALL SNOW BY CHRISTMAS EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

UPDATE.......RK
AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 181628
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1128 AM EST THU DEC 18 2014

.UPDATE...

AREAS OF PATCHY FREEZING DRIZZLE WILL CONTINUE TO IMPACT SOUTHEAST
MICHIGAN THROUGH EARLY AFTERNOON. CURRENT RADAR IMAGERY AND LOCAL
OBSERVATIONS ARE SHOWING FREEZING DRIZZLE FILTERING INTO
SOUTHEAST MICHIGAN. PLENTY OF MOISTURE IN THE BOUNDARY LAYER AND
SURFACE TEMPERATURES HOVERING NEAR FREEZING WILL RESULT IN
FREEZING DRIZZLE CONTINUING INTO THE AFTERNOON HOURS. LOCATIONS
MOST LIKELY TO SEE FREEZING DRIZZLE WILL BE BETWEEN THE I 69 AND I
94 CORRIDOR. MOTORISTS SHOULD BE ADVISED IF TRAVELING IN SOUTHEAST
MICHIGAN AS LIGHT ICING ON ROADWAYS COULD LEAD TO SLIPPERY
CONDITIONS MAINLY ON BRIDGES...OVERPASSES...AND EXIT RAMPS. DRIER
AIR WILL BEGIN TO FILTER INTO THE REGION BY LATE
AFTERNOON...CAUSING FREEZING DRIZZLE TO COME TO AN END.

&&

.AVIATION...ISSUED 653 AM EST THU DEC 18 2014

//DISCUSSION...

A WEAKENING SURFACE TROUGH OF LOW PRESSURE WILL SETTLE SLOWLY OVER
SE MICHIGAN DURING THE DAY AND MAINTAIN MVFR CEILING AT ALL TERMINAL
SITES. A FEW POCKETS OF SNOW GRAINS OR VERY LIGHT DRIZZLE/FZDZ WILL
BE POSSIBLE BUT VERY TRANSIENT DURING THE MORNING. THIS WILL BE
MONITORED FOR POTENTIAL UPDATES IF ANY OBSERVATIONS SUGGEST A
VISIBILITY RESTRICTION...WHICH WOULD INDICATE MORE SUBSTANTIAL
ACTIVITY. OTHERWISE...MVFR STRATUS WILL LINGER THROUGH MIDNIGHT
FOLLOWED BY DRY AIR AND LESS CLOUDS TOWARD SUNRISE AS THE TROUGH
WEAKENS AND THE WIND TURNS MORE FROM THE NORTH.

FOR DTW... MVFR CEILING WILL BE FIRMLY IN PLACE THROUGH THE DAY WITH
PRECIPITATION LIMITED TO VERY LIGHT AND BRIEF SNOW GRAINS OR
DRIZZLE/FZDZ DURING THE MORNING. NO OPERATIONAL IMPACT IS EXPECTED
AND THE POTENTIAL WILL DIMINISH AS THE TROUGH WEAKENS DURING THE
MORNING. THIS WILL NOT BE CARRIED IN THE FORECAST BUT WILL BE
MONITORED FOR SIGNS OF INCREASED ACTIVITY. MVFR CLOUDS WILL LINGER
THROUGH THE NIGHT AND THEN DIMINISH FROM NORTH TO SOUTH AFTER
SUNRISE FRIDAY.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY THROUGH TONIGHT.

&&

.PREV DISCUSSION...ISSUED 347 AM EST THU DEC 18 2014

SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENSIS OVER THE WESTERN GREAT LAKES ON
TUESDAY AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT
UPPER LEVEL JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS
HEIGHTS FALL. THE AREA LOOKS TO BE IN THE WARM SECTOR DURING THE
FIRST PART OF THIS EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A
STRONG PUSH OF COLD AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO
ALL SNOW BY CHRISTMAS EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

UPDATE.......RK
AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 181153
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
653 AM EST THU DEC 18 2014

.AVIATION...

//DISCUSSION...

A WEAKENING SURFACE TROUGH OF LOW PRESSURE WILL SETTLE SLOWLY OVER
SE MICHIGAN DURING THE DAY AND MAINTAIN MVFR CEILING AT ALL TERMINAL
SITES. A FEW POCKETS OF SNOW GRAINS OR VERY LIGHT DRIZZLE/FZDZ WILL
BE POSSIBLE BUT VERY TRANSIENT DURING THE MORNING. THIS WILL BE
MONITORED FOR POTENTIAL UPDATES IF ANY OBSERVATIONS SUGGEST A
VISIBILITY RESTRICTION...WHICH WOULD INDICATE MORE SUBSTANTIAL
ACTIVITY. OTHERWISE...MVFR STRATUS WILL LINGER THROUGH MIDNIGHT
FOLLOWED BY DRY AIR AND LESS CLOUDS TOWARD SUNRISE AS THE TROUGH
WEAKENS AND THE WIND TURNS MORE FROM THE NORTH.

FOR DTW... MVFR CEILING WILL BE FIRMLY IN PLACE THROUGH THE DAY WITH
PRECIPITATION LIMITED TO VERY LIGHT AND BRIEF SNOW GRAINS OR
DRIZZLE/FZDZ DURING THE MORNING. NO OPERATIONAL IMPACT IS EXPECTED
AND THE POTENTIAL WILL DIMINISH AS THE TROUGH WEAKENS DURING THE
MORNING. THIS WILL NOT BE CARRIED IN THE FORECAST BUT WILL BE
MONITORED FOR SIGNS OF INCREASED ACTIVITY. MVFR CLOUDS WILL LINGER
THROUGH THE NIGHT AND THEN DIMINISH FROM NORTH TO SOUTH AFTER
SUNRISE FRIDAY.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY THROUGH TONIGHT.

&&

.PREV DISCUSSION...ISSUED 347 AM EST THU DEC 18 2014

SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENESIS OVER THE WESTERN GREAT LAKES ON TUESDAY
AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT UPPER LEVEL
JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS HEIGHTS FALL. THE
AREA LOOKS TO BE IN THE WARM SECTOR DURING THE FIRST PART OF THIS
EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A STRONG PUSH OF COLD
AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO ALL SNOW BY CHRISTMAS
EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 181153
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
653 AM EST THU DEC 18 2014

.AVIATION...

//DISCUSSION...

A WEAKENING SURFACE TROUGH OF LOW PRESSURE WILL SETTLE SLOWLY OVER
SE MICHIGAN DURING THE DAY AND MAINTAIN MVFR CEILING AT ALL TERMINAL
SITES. A FEW POCKETS OF SNOW GRAINS OR VERY LIGHT DRIZZLE/FZDZ WILL
BE POSSIBLE BUT VERY TRANSIENT DURING THE MORNING. THIS WILL BE
MONITORED FOR POTENTIAL UPDATES IF ANY OBSERVATIONS SUGGEST A
VISIBILITY RESTRICTION...WHICH WOULD INDICATE MORE SUBSTANTIAL
ACTIVITY. OTHERWISE...MVFR STRATUS WILL LINGER THROUGH MIDNIGHT
FOLLOWED BY DRY AIR AND LESS CLOUDS TOWARD SUNRISE AS THE TROUGH
WEAKENS AND THE WIND TURNS MORE FROM THE NORTH.

FOR DTW... MVFR CEILING WILL BE FIRMLY IN PLACE THROUGH THE DAY WITH
PRECIPITATION LIMITED TO VERY LIGHT AND BRIEF SNOW GRAINS OR
DRIZZLE/FZDZ DURING THE MORNING. NO OPERATIONAL IMPACT IS EXPECTED
AND THE POTENTIAL WILL DIMINISH AS THE TROUGH WEAKENS DURING THE
MORNING. THIS WILL NOT BE CARRIED IN THE FORECAST BUT WILL BE
MONITORED FOR SIGNS OF INCREASED ACTIVITY. MVFR CLOUDS WILL LINGER
THROUGH THE NIGHT AND THEN DIMINISH FROM NORTH TO SOUTH AFTER
SUNRISE FRIDAY.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY THROUGH TONIGHT.

&&

.PREV DISCUSSION...ISSUED 347 AM EST THU DEC 18 2014

SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENESIS OVER THE WESTERN GREAT LAKES ON TUESDAY
AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT UPPER LEVEL
JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS HEIGHTS FALL. THE
AREA LOOKS TO BE IN THE WARM SECTOR DURING THE FIRST PART OF THIS
EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A STRONG PUSH OF COLD
AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO ALL SNOW BY CHRISTMAS
EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 180847
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
347 AM EST THU DEC 18 2014

.SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENESIS OVER THE WESTERN GREAT LAKES ON TUESDAY
AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT UPPER LEVEL
JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS HEIGHTS FALL. THE
AREA LOOKS TO BE IN THE WARM SECTOR DURING THE FIRST PART OF THIS
EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A STRONG PUSH OF COLD
AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO ALL SNOW BY CHRISTMAS
EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

&&

.MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.AVIATION...ISSUED 1159 PM EST WED DEC 17 2014

//DISCUSSION...

EXTENSIVE STRATUS DECK WILL HOLD FIRM THROUGH THE TAF PERIOD GIVEN
SUFFICIENT MOISTURE TRAPPED BENEATH A STRONG INVERSION.  RECENT
OBSERVATIONAL TRENDS SUPPORT A RENEWED PERIOD OF MVFR CEILING.
THESE TRENDS DO SUGGEST THAT CEILING HEIGHTS MAY FALL BELOW 2000 FT
AT TIMES THROUGH THE MORNING PERIOD.  LITTLE VARIABILITY IN THIS
CONDITION IS EXPECTED WELL INTO THURSDAY PER RECENT MODEL SOUNDING
DATA.  MODEST WEST TO WEST-NORTHWEST WINDS THROUGH THE PERIOD.

FOR DTW...UPSTREAM TRENDS INDICATE CONDITIONS WILL RETURN TO MVFR
DURING THE EARLY MORNING PERIOD.  MVFR STRATUS WILL HOLD THROUGH
THURSDAY.  THERE IS THE POTENTIAL FOR A PERIOD OF CIGS BELOW 2000 FT
THIS MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 180847
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
347 AM EST THU DEC 18 2014

.SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENESIS OVER THE WESTERN GREAT LAKES ON TUESDAY
AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT UPPER LEVEL
JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS HEIGHTS FALL. THE
AREA LOOKS TO BE IN THE WARM SECTOR DURING THE FIRST PART OF THIS
EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A STRONG PUSH OF COLD
AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO ALL SNOW BY CHRISTMAS
EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

&&

.MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.AVIATION...ISSUED 1159 PM EST WED DEC 17 2014

//DISCUSSION...

EXTENSIVE STRATUS DECK WILL HOLD FIRM THROUGH THE TAF PERIOD GIVEN
SUFFICIENT MOISTURE TRAPPED BENEATH A STRONG INVERSION.  RECENT
OBSERVATIONAL TRENDS SUPPORT A RENEWED PERIOD OF MVFR CEILING.
THESE TRENDS DO SUGGEST THAT CEILING HEIGHTS MAY FALL BELOW 2000 FT
AT TIMES THROUGH THE MORNING PERIOD.  LITTLE VARIABILITY IN THIS
CONDITION IS EXPECTED WELL INTO THURSDAY PER RECENT MODEL SOUNDING
DATA.  MODEST WEST TO WEST-NORTHWEST WINDS THROUGH THE PERIOD.

FOR DTW...UPSTREAM TRENDS INDICATE CONDITIONS WILL RETURN TO MVFR
DURING THE EARLY MORNING PERIOD.  MVFR STRATUS WILL HOLD THROUGH
THURSDAY.  THERE IS THE POTENTIAL FOR A PERIOD OF CIGS BELOW 2000 FT
THIS MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 180847
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
347 AM EST THU DEC 18 2014

.SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENESIS OVER THE WESTERN GREAT LAKES ON TUESDAY
AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT UPPER LEVEL
JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS HEIGHTS FALL. THE
AREA LOOKS TO BE IN THE WARM SECTOR DURING THE FIRST PART OF THIS
EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A STRONG PUSH OF COLD
AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO ALL SNOW BY CHRISTMAS
EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

&&

.MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.AVIATION...ISSUED 1159 PM EST WED DEC 17 2014

//DISCUSSION...

EXTENSIVE STRATUS DECK WILL HOLD FIRM THROUGH THE TAF PERIOD GIVEN
SUFFICIENT MOISTURE TRAPPED BENEATH A STRONG INVERSION.  RECENT
OBSERVATIONAL TRENDS SUPPORT A RENEWED PERIOD OF MVFR CEILING.
THESE TRENDS DO SUGGEST THAT CEILING HEIGHTS MAY FALL BELOW 2000 FT
AT TIMES THROUGH THE MORNING PERIOD.  LITTLE VARIABILITY IN THIS
CONDITION IS EXPECTED WELL INTO THURSDAY PER RECENT MODEL SOUNDING
DATA.  MODEST WEST TO WEST-NORTHWEST WINDS THROUGH THE PERIOD.

FOR DTW...UPSTREAM TRENDS INDICATE CONDITIONS WILL RETURN TO MVFR
DURING THE EARLY MORNING PERIOD.  MVFR STRATUS WILL HOLD THROUGH
THURSDAY.  THERE IS THE POTENTIAL FOR A PERIOD OF CIGS BELOW 2000 FT
THIS MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 180847
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
347 AM EST THU DEC 18 2014

.SHORT TERM... TODAY AND TONIGHT

A BRIEF PERIOD OF FREEZING DRIZZLE AND SNOW GRAINS OBSERVED HERE
LOCALLY TO MATCH UP WITH RADAR AND LIGHT VISIBILITY RESTRICTION IN A
FEW THUMB LOCATIONS TO CARRY A MENTION IN THE FORECAST DURING THE
EARLY MORNING. EXPECT THE WEAKENING LOW LEVEL WIND FIELD AND
CORRESPONDING LOSS OF SHEAR AT THE INVERSION LAYER WILL CAUSE THE
PATTERN TO DISSIPATE BY MID MORNING. THE REMAINING BOUNDARY LAYER
MOISTURE WILL KEEP CLOUDS LOCKED IN OVER LOWER MICHIGAN FOR THE REST
OF THE DAY AND THE WIND WILL DIMINISH COMPARED TO YESTERDAY. THE
LIGHT WIND WILL MAKE IT EASIER TO TAKE TEMPERATURES IN THE 20S TO
START THE DAY WHICH WILL THEN STRUGGLE TO MAKE THE MID 30S DURING
THE AFTERNOON. THE CLOUDS WILL BE SUPPORTED MAINLY BY BOUNDARY LAYER
CONVERGENCE WITHIN THE WEAK SURFACE PRESSURE TROUGH THAT WILL SETTLE
SLOWLY FROM NORTHERN LOWER INTO SOUTHERN LOWER MICHIGAN DURING THE
DAY. 00Z OBSERVED AND MODEL SOUNDINGS ALSO SHOW A WELL DEFINED
SUBSIDENCE INVERSION BASED AT ABOUT 900 MB THAT WILL PREVENT MIXING
OF BOUNDARY LAYER MOISTURE AND ANY RESULTING CLOUD EROSION. THE
INVERSION WILL BE MAINTAINED THROUGH THE DAY BY CONFLUENT FLOW ALOFT
DOWNSTREAM OF THE BLOCKING UPPER LEVEL RIDGE EXTENDING FROM HUDSON
BAY INTO THE UPPER MIDWEST.

DURING THE LATE AFTERNOON AND TONIGHT...THE POTENTIAL FOR LAKE
EFFECT SNOW IN THE THUMB IS KEPT IN MIND AS LOW LEVEL FLOW VEERS
TOWARD THE NORTH. EARLY MORNING OBSERVATIONS FROM THE CANADIAN RADAR
IN EXETER INDICATE THE SURFACE TROUGH FOCUSING SOME MODEST LAKE
EFFECT SNOW SHOWERS INTO SOUTHERN ONTARIO. THIS MATCHES UP WITH
MODEL SOUNDINGS THAT SHOW CONVECTIVE DEPTH UP TO ABOUT 850 MB WITH
DELTA THETA-E NEAR 4K OR LI ABOUT -1C. THERE IS ALSO SOME SEEDING OF
THE DGZ FROM MID LEVEL MOISTURE THAT WILL BE STRIPPING AWAY DURING
THE MORNING. THIS SHOULD RESULT IN A DIMINISHING TREND BEFORE THE
WIND STARTS TO VEER. THEN...BY TONIGHT...DRY AIR COMING DOWN FROM
NORTH OF LAKE HURON WILL MAINTAIN A DRY DGZ AND FURTHER SUPPRESS
CONVECTIVE DEPTH TO 900 MB/3000 FEET OR LESS WHILE INSTABILITY
WITHIN THE LAYER DECREASES. THESE CONDITIONS WILL NOT SUPPORT ANY
MEANINGFUL SNOW SHOWERS AND MAY NOT EVEN BE GOOD ENOUGH FOR CLOUDS
OVERNIGHT THROUGH SUNRISE FRIDAY.

&&

.LONG TERM...FRIDAY THROUGH WEDNESDAY

HIGH PRESSURE WILL BE IN CONTROL OF THE CENTRAL GREAT LAKES LATE IN
THE WEEK AND THROUGH THE WEEKEND.  TEMPERATURES WILL BE RIGHT AROUND
NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE LOW TO MID 30S AND
LOWS IN THE LOW TO MID 20S.  THE MAIN CONCERN DURING THIS PERIOD
WILL BE CLOUDS ON FRIDAY AS PREVIOUS MODEL RUNS INDICATED LINGERING
STRATUS DURING THE DAY WITH LOW LEVEL MOISTURE TRAPPED UNDERNEATH AN
INVERSION.  HOWEVER RECENT MODEL SOUNDINGS INDICATE A DECENT PUSH OF
LOW LEVEL DRY AIR MAKING ITS WAY FROM THE LAKE SUPERIOR REGION ON
FRIDAY...CLEARING OUT THE CLOUDS AND LINGERING LOW LEVEL MOISTURE
ACROSS SOUTHEAST MICHIGAN. GIVEN THE MODEL AGREEMENT AND RECENT
MODEL TRENDS WILL BE MORE OPTIMISTIC WITH CLOUD COVER DURING THE DAY
ON FRIDAY.  A WEAK MID LEVEL SHORTWAVE TRACKING THROUGH THE SOUTHERN
GREAT LAKES SATURDAY AND SATURDAY NIGHT IS EXPECTED TO BE NOTED ONLY
BY THE CLOUD COVER IN THE MID LEVELS.

THE MAIN SYSTEM OF NOTE IN THE EXTENDED IS A STRONG LOW PRESSURE
SYSTEM THAT COMES TOGETHER OVER THE GREAT LAKES REGION DURING THE
EARLY TO MIDDLE PART OF NEXT WEEK.  THE FIRST PART OF THIS SYSTEM
WILL BE NOTED BY WARMING TEMPERATURES ON MONDAY AS A CLIPPER SYSTEM
DEVELOPS OVER THE NORTHERN PLAINS.  THIS SYSTEM WILL THEN STALL AND
RAPIDLY UNDERGO CYCLOGENESIS OVER THE WESTERN GREAT LAKES ON TUESDAY
AS IT GETS REINFORCEMENTS FROM A VERY STRONG 140 KNOT UPPER LEVEL
JET AS THE MID LEVEL TROUGH BECOMES CLOSED OFF AS HEIGHTS FALL. THE
AREA LOOKS TO BE IN THE WARM SECTOR DURING THE FIRST PART OF THIS
EVENT ON TUESDAY...WITH MAINLY RAIN EXPECTED. A STRONG PUSH OF COLD
AIR TUESDAY NIGHT WILL CHANGEOVER THE RAIN TO ALL SNOW BY CHRISTMAS
EVE.

THE MAIN QUESTION THEN BECOMES HOW MUCH WRAP AROUND MOISTURE
WILL BE AVAILABLE FOR SNOWFALL ONCE THE MAIN SYSTEM AND MOISTURE
HEAD EAST AS THE SYSTEM DEEPENS FURTHER ACROSS THE MIDDLE ATLANTIC
STATES.  AT THIS POINT IT APPEARS MEAGER AMOUNTS OF MOISTURE WILL
BRING A FEW TENTHS OF AN INCH OF SNOWFALL ON CHRISTMAS EVE BEHIND
THE COLD FRONT...HOWEVER ADDITIONAL MOISTURE FROM THE GREAT LAKES
COULD CERTAINLY BOOST VALUES SOME IF LAKE EFFECT BANDS BECOME
VIGOROUS.  AT THIS POINT IT APPEARS CONFIDENCE IN THE SYSTEM PLAYING
OUT IN THIS GENERAL SENSE IS MEDIUM TO HIGH GIVEN THE MODEL
AGREEMENT...HOWEVER THERE IS QUITE A BIT OF UNCERTAINTY REGARDING
SNOWFALL AMOUNTS AS THE GFS HAS A MUCH BIGGER PUSH OF COLD AIR WHICH
IS NOT SURPRISING AS IT PHASES THE SYSTEMS QUICKER AND DEEPENS THE
LOW SOONER THAN THE ECMWF.  FURTHER RUNS WILL BE NEEDED BEFORE
WORKING OUT THE DETAILS REGARDING THIS SYSTEM AT THE TAIL END OF THE
EXTENDED.

&&

.MARINE...

HIGH PRESSURE WILL BUILD INTO THE AREA TODAY...BRINGING LIGHTER
WINDS TO THE MARINE AREAS.  WINDS AND WAVES HAVE FALLEN BELOW SMALL
CRAFT ADVISORY CRITERIA...THEREFORE THE HEADLINES WILL BE ALLOWED TO
EXPIRE AS ANTICIPATED.  THE HIGH WILL PROVIDE LIGHT WINDS AND WAVES
THROUGH THE WEEKEND.

&&

.AVIATION...ISSUED 1159 PM EST WED DEC 17 2014

//DISCUSSION...

EXTENSIVE STRATUS DECK WILL HOLD FIRM THROUGH THE TAF PERIOD GIVEN
SUFFICIENT MOISTURE TRAPPED BENEATH A STRONG INVERSION.  RECENT
OBSERVATIONAL TRENDS SUPPORT A RENEWED PERIOD OF MVFR CEILING.
THESE TRENDS DO SUGGEST THAT CEILING HEIGHTS MAY FALL BELOW 2000 FT
AT TIMES THROUGH THE MORNING PERIOD.  LITTLE VARIABILITY IN THIS
CONDITION IS EXPECTED WELL INTO THURSDAY PER RECENT MODEL SOUNDING
DATA.  MODEST WEST TO WEST-NORTHWEST WINDS THROUGH THE PERIOD.

FOR DTW...UPSTREAM TRENDS INDICATE CONDITIONS WILL RETURN TO MVFR
DURING THE EARLY MORNING PERIOD.  MVFR STRATUS WILL HOLD THROUGH
THURSDAY.  THERE IS THE POTENTIAL FOR A PERIOD OF CIGS BELOW 2000 FT
THIS MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.

&&

$$

SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 180459
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1159 PM EST WED DEC 17 2014

.AVIATION...

//DISCUSSION...

EXTENSIVE STRATUS DECK WILL HOLD FIRM THROUGH THE TAF PERIOD GIVEN
SUFFICIENT MOISTURE TRAPPED BENEATH A STRONG INVERSION.  RECENT
OBSERVATIONAL TRENDS SUPPORT A RENEWED PERIOD OF MVFR CEILING.
THESE TRENDS DO SUGGEST THAT CEILING HEIGHTS MAY FALL BELOW 2000 FT
AT TIMES THROUGH THE MORNING PERIOD.  LITTLE VARIABILITY IN THIS
CONDITION IS EXPECTED WELL INTO THURSDAY PER RECENT MODEL SOUNDING
DATA.  MODEST WEST TO WEST-NORTHWEST WINDS THROUGH THE PERIOD.

FOR DTW...UPSTREAM TRENDS INDICATE CONDITIONS WILL RETURN TO MVFR
DURING THE EARLY MORNING PERIOD.  MVFR STRATUS WILL HOLD THROUGH
THURSDAY.  THERE IS THE POTENTIAL FOR A PERIOD OF CIGS BELOW 2000 FT
THIS MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.PREV DISCUSSION...ISSUED 326 PM EST WED DEC 17 2014

SHORT TERM...THROUGH TONIGHT

STRONG UPPER WAVE EMBEDDED WITHIN THE LONGWAVE TROUGH OVER THE GREAT
LAKES AND NEW ENGLAND WILL MOVE ACROSS LOWER MICHIGAN THIS AFTERNOON
AND EARLY EVENING. THIS WILL DRAG AN AREA OF MID-LEVEL DEFORMATION
DOWN ACROSS NORTHERN AND CENTRAL MICHIGAN AS IT TRACKS EAST THROUGH
THE AREA...AND ALSO PULL A SURFACE TROUGH NOW EXTENDING BACK FROM
THE MAIN LOW CENTER OVER SOUTHERN ONTARIO/QUEBEC DOWN INTO CENTRAL
MICHIGAN.

CURRENTLY...WIDESPREAD SNOW SHOWERS ARE DEVELOPING OVER NORTHERN
LOWER MICHIGAN WITHIN THE AREA OF DEFORMATION...DEEPER MOISTURE TO
SATURATE THE DENDRITIC GROWTH ZONE...AND AHEAD OF THE TROUGH AXIS.
ACTIVITY IS ALSO GETTING A BOOST FROM MOISTURE FLUX OFF LAKE
MICHIGAN. AREA OF BETTER FORCING AND DEEPER MOISTURE LOOKS TO JUST
CLIP THE SAGINAW VALLEY AND THUMB FROM LATE THIS AFTERNOON THROUGH
ABOUT 9 PM...WITH LIFT WEAKENING AND STEEPER LAPSE RATES FROM THE
UPPER COLD POOL SHIFTING EAST WITH THE UPPER LOW AND SURFACE TROUGH
TONIGHT. THIS SHOULD PREVENT ACTIVITY FROM SEEPING FURTHER
SOUTH...AND KEEP THE REMAINDER OF THE NIGHT FAIRLY QUIET OUTSIDE OF
SOME POTENTIAL FOR LIGHT LAKE EFFECT BANDS TO BRUSH THE THUMB. SNOW
AMOUNTS OVER THE SAGINAW VALLEY AND NORTHERN THUMB SHOULD BE FAIRLY
LIGHT GIVEN ONLY 1 G/KG OF SPECIFIC HUMIDITY AND WEAKENING
FORCING...WITH AMOUNTS EXPECTED TO TOP OUT AROUND 0.5 INCHES.

FURTHER SOUTH THIS EVENING...LAKE EFFECT PROCESSES FROM OFF LAKE
MICHIGAN WILL CONTINUE TO BRING THE CHANCE FOR FLURRIES OR EVEN A
LIGHT SNOW SHOWER THIS EVENING BEFORE DRIER AIR ARRIVES AND THE EXIT
OF THE UPPER COLD POOL ALLOWS LAPSE RATES TO BECOME MORE STABLE.
BEST POTENTIAL WILL BE BEFORE 8 PM...AS UPPER COLD POOL BRIEFLY
STEEPENS LAPSE RATES.

CLOUDS ARE EXPECTED TO REMAIN LOCKED INTO PLACE TONIGHT UNDER AN
INVERSION. THIS SHOULD PREVENT TEMPERATURES FROM FALLING TOO FAR
TONIGHT...WITH MINS IN THE MID 20S EXPECTED.

LONG TERM...THURSDAY THROUGH TUESDAY

THE END OF THE WEEK WILL REMAIN RELATIVELY QUIET AS HIGH PRESSURE
BUILDS IN OVER THE REGION BEHIND THE EXITING SURFACE TROUGH.
NORTHERLY FLOW WILL SLACKEN AS THE GRADIENT RELAXES AND DRIER AIR
FILTERS IN FROM THE NORTH.  THE ONE ISSUE EARLY ON IN THE EXTENDED
IS THE CHANCE FOR SOME LINGERING SNOW SHOWERS OVER THE THUMB AREA
WITH THE NORTHERLY FLOW...ESPECIALLY THURSDAY MORNING.  LATEST MODEL
RUNS SHOWED WEAKENING OF THE GRADIENT AND WITH DRIER AIR MOVING IN
HAVE DECREASED POPS WHILE LEAVING IN A MENTION OF FLURRIES THROUGH
THURSDAY NIGHT.  CONTINUED CLOUDY CONDITIONS WILL BE SEEN THROUGH THE
DAY ON THURSDAY BEFORE SKIES ARE EXPECTED TO SLIGHTLY IMPROVE
FRIDAY.  HOWEVER...GIVEN THIS TIME OF YEAR WOULD NOT BE SURPRISED IF
LOW CLOUDS REMAINED WHICH HAS BEEN THE CASE LATELY.

ALL SIGNS STILL POINT TO A QUIET WEEKEND AS ASCENT FROM
DEAMPLIFYING WAVE IS STILL SHOWN BY NWP SOLUTIONS TO PASS WELL TO
OUR SOUTH. CONTINUED DRY AND A BIT WARMER MONDAY AHEAD OF A CLIPPER
TYPE SYSTEM ORGANIZING OVER THE NORTHERN PLAINS. REMAINDER OF THE
FORECAST THROUGH CHRISTMAS EVE WILL HINGE UPON VERY STRONG PAC NW
JET ENERGY CARVING OUT A DEEP LONGWAVE TROUGH OVER THE CENTRAL
CONUS. INDICATIONS ARE THAT THE CLIPPER WILL SLOW IN RESPONSE TO
THIS JET ENERGY AND EVENTUALLY BE ABSORBED INTO A STRONGER SURFACE
LOW LIFTING INTO THE GREAT LAKES FROM THE DEEP SOUTH. 12Z MODELS
INDICATE THE CYCLONE BECOMING QUITE DEEP BY THE TIME IT REACHES OUR
AREA. DETAILS IN TERMS OF PRECIP TYPE WILL DEPEND ON THE LOW
TRACK...WITH LOW CONFIDENCE AT THIS POINT...BUT CURRENT INDICATIONS
ARE THAT IMPACTFUL WEATHER WILL BECOME MORE LIKELY TOWARD CHRISTMAS
EVE.

MARINE...

GUSTY WINDS ON WEDNESDAY WILL EVENTUALLY SLACKEN AS A LOW PRESSURE
SYSTEM AND ASSOCIATED SURFACE TROUGH PUSH TO THE EAST OVERNIGHT.
SNOW SHOWERS ARE ALSO POSSIBLE THROUGH THE EVENING AS THE TROUGH
SWINGS THROUGH. AS WESTERLY/NORTHWESTERLY FLOW IS MAINTAINED THROUGH
THE OVERNIGHT HOURS...THE SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY
ALONG WITH LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH WILL BE
CONTINUED.  HIGH PRESSURE THEN BUILDS IN ON THURSDAY WHICH WILL
BRING LIGHTER NORTHERLY WINDS TO THE MARINE AREAS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....MR
SHORT TERM...HLO
LONG TERM....SS/DT
MARINE.......SS

YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 180459
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1159 PM EST WED DEC 17 2014

.AVIATION...

//DISCUSSION...

EXTENSIVE STRATUS DECK WILL HOLD FIRM THROUGH THE TAF PERIOD GIVEN
SUFFICIENT MOISTURE TRAPPED BENEATH A STRONG INVERSION.  RECENT
OBSERVATIONAL TRENDS SUPPORT A RENEWED PERIOD OF MVFR CEILING.
THESE TRENDS DO SUGGEST THAT CEILING HEIGHTS MAY FALL BELOW 2000 FT
AT TIMES THROUGH THE MORNING PERIOD.  LITTLE VARIABILITY IN THIS
CONDITION IS EXPECTED WELL INTO THURSDAY PER RECENT MODEL SOUNDING
DATA.  MODEST WEST TO WEST-NORTHWEST WINDS THROUGH THE PERIOD.

FOR DTW...UPSTREAM TRENDS INDICATE CONDITIONS WILL RETURN TO MVFR
DURING THE EARLY MORNING PERIOD.  MVFR STRATUS WILL HOLD THROUGH
THURSDAY.  THERE IS THE POTENTIAL FOR A PERIOD OF CIGS BELOW 2000 FT
THIS MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.PREV DISCUSSION...ISSUED 326 PM EST WED DEC 17 2014

SHORT TERM...THROUGH TONIGHT

STRONG UPPER WAVE EMBEDDED WITHIN THE LONGWAVE TROUGH OVER THE GREAT
LAKES AND NEW ENGLAND WILL MOVE ACROSS LOWER MICHIGAN THIS AFTERNOON
AND EARLY EVENING. THIS WILL DRAG AN AREA OF MID-LEVEL DEFORMATION
DOWN ACROSS NORTHERN AND CENTRAL MICHIGAN AS IT TRACKS EAST THROUGH
THE AREA...AND ALSO PULL A SURFACE TROUGH NOW EXTENDING BACK FROM
THE MAIN LOW CENTER OVER SOUTHERN ONTARIO/QUEBEC DOWN INTO CENTRAL
MICHIGAN.

CURRENTLY...WIDESPREAD SNOW SHOWERS ARE DEVELOPING OVER NORTHERN
LOWER MICHIGAN WITHIN THE AREA OF DEFORMATION...DEEPER MOISTURE TO
SATURATE THE DENDRITIC GROWTH ZONE...AND AHEAD OF THE TROUGH AXIS.
ACTIVITY IS ALSO GETTING A BOOST FROM MOISTURE FLUX OFF LAKE
MICHIGAN. AREA OF BETTER FORCING AND DEEPER MOISTURE LOOKS TO JUST
CLIP THE SAGINAW VALLEY AND THUMB FROM LATE THIS AFTERNOON THROUGH
ABOUT 9 PM...WITH LIFT WEAKENING AND STEEPER LAPSE RATES FROM THE
UPPER COLD POOL SHIFTING EAST WITH THE UPPER LOW AND SURFACE TROUGH
TONIGHT. THIS SHOULD PREVENT ACTIVITY FROM SEEPING FURTHER
SOUTH...AND KEEP THE REMAINDER OF THE NIGHT FAIRLY QUIET OUTSIDE OF
SOME POTENTIAL FOR LIGHT LAKE EFFECT BANDS TO BRUSH THE THUMB. SNOW
AMOUNTS OVER THE SAGINAW VALLEY AND NORTHERN THUMB SHOULD BE FAIRLY
LIGHT GIVEN ONLY 1 G/KG OF SPECIFIC HUMIDITY AND WEAKENING
FORCING...WITH AMOUNTS EXPECTED TO TOP OUT AROUND 0.5 INCHES.

FURTHER SOUTH THIS EVENING...LAKE EFFECT PROCESSES FROM OFF LAKE
MICHIGAN WILL CONTINUE TO BRING THE CHANCE FOR FLURRIES OR EVEN A
LIGHT SNOW SHOWER THIS EVENING BEFORE DRIER AIR ARRIVES AND THE EXIT
OF THE UPPER COLD POOL ALLOWS LAPSE RATES TO BECOME MORE STABLE.
BEST POTENTIAL WILL BE BEFORE 8 PM...AS UPPER COLD POOL BRIEFLY
STEEPENS LAPSE RATES.

CLOUDS ARE EXPECTED TO REMAIN LOCKED INTO PLACE TONIGHT UNDER AN
INVERSION. THIS SHOULD PREVENT TEMPERATURES FROM FALLING TOO FAR
TONIGHT...WITH MINS IN THE MID 20S EXPECTED.

LONG TERM...THURSDAY THROUGH TUESDAY

THE END OF THE WEEK WILL REMAIN RELATIVELY QUIET AS HIGH PRESSURE
BUILDS IN OVER THE REGION BEHIND THE EXITING SURFACE TROUGH.
NORTHERLY FLOW WILL SLACKEN AS THE GRADIENT RELAXES AND DRIER AIR
FILTERS IN FROM THE NORTH.  THE ONE ISSUE EARLY ON IN THE EXTENDED
IS THE CHANCE FOR SOME LINGERING SNOW SHOWERS OVER THE THUMB AREA
WITH THE NORTHERLY FLOW...ESPECIALLY THURSDAY MORNING.  LATEST MODEL
RUNS SHOWED WEAKENING OF THE GRADIENT AND WITH DRIER AIR MOVING IN
HAVE DECREASED POPS WHILE LEAVING IN A MENTION OF FLURRIES THROUGH
THURSDAY NIGHT.  CONTINUED CLOUDY CONDITIONS WILL BE SEEN THROUGH THE
DAY ON THURSDAY BEFORE SKIES ARE EXPECTED TO SLIGHTLY IMPROVE
FRIDAY.  HOWEVER...GIVEN THIS TIME OF YEAR WOULD NOT BE SURPRISED IF
LOW CLOUDS REMAINED WHICH HAS BEEN THE CASE LATELY.

ALL SIGNS STILL POINT TO A QUIET WEEKEND AS ASCENT FROM
DEAMPLIFYING WAVE IS STILL SHOWN BY NWP SOLUTIONS TO PASS WELL TO
OUR SOUTH. CONTINUED DRY AND A BIT WARMER MONDAY AHEAD OF A CLIPPER
TYPE SYSTEM ORGANIZING OVER THE NORTHERN PLAINS. REMAINDER OF THE
FORECAST THROUGH CHRISTMAS EVE WILL HINGE UPON VERY STRONG PAC NW
JET ENERGY CARVING OUT A DEEP LONGWAVE TROUGH OVER THE CENTRAL
CONUS. INDICATIONS ARE THAT THE CLIPPER WILL SLOW IN RESPONSE TO
THIS JET ENERGY AND EVENTUALLY BE ABSORBED INTO A STRONGER SURFACE
LOW LIFTING INTO THE GREAT LAKES FROM THE DEEP SOUTH. 12Z MODELS
INDICATE THE CYCLONE BECOMING QUITE DEEP BY THE TIME IT REACHES OUR
AREA. DETAILS IN TERMS OF PRECIP TYPE WILL DEPEND ON THE LOW
TRACK...WITH LOW CONFIDENCE AT THIS POINT...BUT CURRENT INDICATIONS
ARE THAT IMPACTFUL WEATHER WILL BECOME MORE LIKELY TOWARD CHRISTMAS
EVE.

MARINE...

GUSTY WINDS ON WEDNESDAY WILL EVENTUALLY SLACKEN AS A LOW PRESSURE
SYSTEM AND ASSOCIATED SURFACE TROUGH PUSH TO THE EAST OVERNIGHT.
SNOW SHOWERS ARE ALSO POSSIBLE THROUGH THE EVENING AS THE TROUGH
SWINGS THROUGH. AS WESTERLY/NORTHWESTERLY FLOW IS MAINTAINED THROUGH
THE OVERNIGHT HOURS...THE SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY
ALONG WITH LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH WILL BE
CONTINUED.  HIGH PRESSURE THEN BUILDS IN ON THURSDAY WHICH WILL
BRING LIGHTER NORTHERLY WINDS TO THE MARINE AREAS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....MR
SHORT TERM...HLO
LONG TERM....SS/DT
MARINE.......SS

YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 172256
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
556 PM EST WED DEC 17 2014

.AVIATION...

//DISCUSSION...

EXTENSIVE STRATUS DECK WILL HOLD FIRM THROUGH THE TAF PERIOD GIVEN
SUFFICIENT MOISTURE TRAPPED BENEATH A STRONG INVERSION.  SLIGHT
FLUCTUATION IN CEILING HEIGHTS WILL OCCUR AT TIMES...BUT WILL
PRIMARILY CENTER WITHIN THE 2500 TO 3500 FT RANGE.  MOISTURE DEPTH
WILL BE ADEQUATE TO GENERATE THE OCCASIONAL FLURRY...BOTH COVERAGE
AND DURATION TOO LIMITED TO INCLUDE A MENTION.  DIMINISHING
GUSTINESS OF THE PREVAILING WESTERLY GRADIENT WILL THE LOSS OF
HEATING.  WINDS WILL VEER SLIGHTLY WITH THE PASSAGE OF A SURFACE
TROUGH OVERNIGHT.

FOR DTW...CONDITIONS WILL PRIMARILY REMAIN AT MVFR UNDER THE
EXISTING STRATUS.  A BRIEF CLIMB INTO LOWER VFR WILL BE PLAUSIBLE
YET THIS EVENING BEFORE INVERSION HEIGHTS LOWER AGAIN OVERNIGHT WITH
THE PASSAGE OF A SURFACE TROUGH.  WESTERLY WINDS WILL EASE WITH TIME
TONIGHT...GRADUALLY VEERING TOWARD WNW BY MID MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.PREV DISCUSSION...ISSUED 326 PM EST WED DEC 17 2014

SHORT TERM...THROUGH TONIGHT

STRONG UPPER WAVE EMBEDDED WITHIN THE LONGWAVE TROUGH OVER THE GREAT
LAKES AND NEW ENGLAND WILL MOVE ACROSS LOWER MICHIGAN THIS AFTERNOON
AND EARLY EVENING. THIS WILL DRAG AN AREA OF MID-LEVEL DEFORMATION
DOWN ACROSS NORTHERN AND CENTRAL MICHIGAN AS IT TRACKS EAST THROUGH
THE AREA...AND ALSO PULL A SURFACE TROUGH NOW EXTENDING BACK FROM
THE MAIN LOW CENTER OVER SOUTHERN ONTARIO/QUEBEC DOWN INTO CENTRAL
MICHIGAN.

CURRENTLY...WIDESPREAD SNOW SHOWERS ARE DEVELOPING OVER NORTHERN
LOWER MICHIGAN WITHIN THE AREA OF DEFORMATION...DEEPER MOISTURE TO
SATURATE THE DENDRITIC GROWTH ZONE...AND AHEAD OF THE TROUGH AXIS.
ACTIVITY IS ALSO GETTING A BOOST FROM MOISTURE FLUX OFF LAKE
MICHIGAN. AREA OF BETTER FORCING AND DEEPER MOISTURE LOOKS TO JUST
CLIP THE SAGINAW VALLEY AND THUMB FROM LATE THIS AFTERNOON THROUGH
ABOUT 9 PM...WITH LIFT WEAKENING AND STEEPER LAPSE RATES FROM THE
UPPER COLD POOL SHIFTING EAST WITH THE UPPER LOW AND SURFACE TROUGH
TONIGHT. THIS SHOULD PREVENT ACTIVITY FROM SEEPING FURTHER
SOUTH...AND KEEP THE REMAINDER OF THE NIGHT FAIRLY QUIET OUTSIDE OF
SOME POTENTIAL FOR LIGHT LAKE EFFECT BANDS TO BRUSH THE THUMB. SNOW
AMOUNTS OVER THE SAGINAW VALLEY AND NORTHERN THUMB SHOULD BE FAIRLY
LIGHT GIVEN ONLY 1 G/KG OF SPECIFIC HUMIDITY AND WEAKENING
FORCING...WITH AMOUNTS EXPECTED TO TOP OUT AROUND 0.5 INCHES.

FURTHER SOUTH THIS EVENING...LAKE EFFECT PROCESSES FROM OFF LAKE
MICHIGAN WILL CONTINUE TO BRING THE CHANCE FOR FLURRIES OR EVEN A
LIGHT SNOW SHOWER THIS EVENING BEFORE DRIER AIR ARRIVES AND THE EXIT
OF THE UPPER COLD POOL ALLOWS LAPSE RATES TO BECOME MORE STABLE.
BEST POTENTIAL WILL BE BEFORE 8 PM...AS UPPER COLD POOL BRIEFLY
STEEPENS LAPSE RATES.

CLOUDS ARE EXPECTED TO REMAIN LOCKED INTO PLACE TONIGHT UNDER AN
INVERSION. THIS SHOULD PREVENT TEMPERATURES FROM FALLING TOO FAR
TONIGHT...WITH MINS IN THE MID 20S EXPECTED.

LONG TERM...THURSDAY THROUGH TUESDAY

THE END OF THE WEEK WILL REMAIN RELATIVELY QUIET AS HIGH PRESSURE
BUILDS IN OVER THE REGION BEHIND THE EXITING SURFACE TROUGH.
NORTHERLY FLOW WILL SLACKEN AS THE GRADIENT RELAXES AND DRIER AIR
FILTERS IN FROM THE NORTH.  THE ONE ISSUE EARLY ON IN THE EXTENDED
IS THE CHANCE FOR SOME LINGERING SNOW SHOWERS OVER THE THUMB AREA
WITH THE NORTHERLY FLOW...ESPECIALLY THURSDAY MORNING.  LATEST MODEL
RUNS SHOWED WEAKENING OF THE GRADIENT AND WITH DRIER AIR MOVING IN
HAVE DECREASED POPS WHILE LEAVING IN A MENTION OF FLURRIES THROUGH
THURSDAY NIGHT.  CONTINUED CLOUDY CONDITIONS WILL BE SEEN THROUGH THE
DAY ON THURSDAY BEFORE SKIES ARE EXPECTED TO SLIGHTLY IMPROVE
FRIDAY.  HOWEVER...GIVEN THIS TIME OF YEAR WOULD NOT BE SURPRISED IF
LOW CLOUDS REMAINED WHICH HAS BEEN THE CASE LATELY.

ALL SIGNS STILL POINT TO A QUIET WEEKEND AS ASCENT FROM
DEAMPLIFYING WAVE IS STILL SHOWN BY NWP SOLUTIONS TO PASS WELL TO
OUR SOUTH. CONTINUED DRY AND A BIT WARMER MONDAY AHEAD OF A CLIPPER
TYPE SYSTEM ORGANIZING OVER THE NORTHERN PLAINS. REMAINDER OF THE
FORECAST THROUGH CHRISTMAS EVE WILL HINGE UPON VERY STRONG PAC NW
JET ENERGY CARVING OUT A DEEP LONGWAVE TROUGH OVER THE CENTRAL
CONUS. INDICATIONS ARE THAT THE CLIPPER WILL SLOW IN RESPONSE TO
THIS JET ENERGY AND EVENTUALLY BE ABSORBED INTO A STRONGER SURFACE
LOW LIFTING INTO THE GREAT LAKES FROM THE DEEP SOUTH. 12Z MODELS
INDICATE THE CYCLONE BECOMING QUITE DEEP BY THE TIME IT REACHES OUR
AREA. DETAILS IN TERMS OF PRECIP TYPE WILL DEPEND ON THE LOW
TRACK...WITH LOW CONFIDENCE AT THIS POINT...BUT CURRENT INDICATIONS
ARE THAT IMPACTFUL WEATHER WILL BECOME MORE LIKELY TOWARD CHRISTMAS
EVE.

MARINE...

GUSTY WINDS ON WEDNESDAY WILL EVENTUALLY SLACKEN AS A LOW PRESSURE
SYSTEM AND ASSOCIATED SURFACE TROUGH PUSH TO THE EAST OVERNIGHT.
SNOW SHOWERS ARE ALSO POSSIBLE THROUGH THE EVENING AS THE TROUGH
SWINGS THROUGH. AS WESTERLY/NORTHWESTERLY FLOW IS MAINTAINED THROUGH
THE OVERNIGHT HOURS...THE SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY
ALONG WITH LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH WILL BE
CONTINUED.  HIGH PRESSURE THEN BUILDS IN ON THURSDAY WHICH WILL
BRING LIGHTER NORTHERLY WINDS TO THE MARINE AREAS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....99
SHORT TERM...HLO
LONG TERM....SS/DT
MARINE.......SS


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 172256
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
556 PM EST WED DEC 17 2014

.AVIATION...

//DISCUSSION...

EXTENSIVE STRATUS DECK WILL HOLD FIRM THROUGH THE TAF PERIOD GIVEN
SUFFICIENT MOISTURE TRAPPED BENEATH A STRONG INVERSION.  SLIGHT
FLUCTUATION IN CEILING HEIGHTS WILL OCCUR AT TIMES...BUT WILL
PRIMARILY CENTER WITHIN THE 2500 TO 3500 FT RANGE.  MOISTURE DEPTH
WILL BE ADEQUATE TO GENERATE THE OCCASIONAL FLURRY...BOTH COVERAGE
AND DURATION TOO LIMITED TO INCLUDE A MENTION.  DIMINISHING
GUSTINESS OF THE PREVAILING WESTERLY GRADIENT WILL THE LOSS OF
HEATING.  WINDS WILL VEER SLIGHTLY WITH THE PASSAGE OF A SURFACE
TROUGH OVERNIGHT.

FOR DTW...CONDITIONS WILL PRIMARILY REMAIN AT MVFR UNDER THE
EXISTING STRATUS.  A BRIEF CLIMB INTO LOWER VFR WILL BE PLAUSIBLE
YET THIS EVENING BEFORE INVERSION HEIGHTS LOWER AGAIN OVERNIGHT WITH
THE PASSAGE OF A SURFACE TROUGH.  WESTERLY WINDS WILL EASE WITH TIME
TONIGHT...GRADUALLY VEERING TOWARD WNW BY MID MORNING.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.PREV DISCUSSION...ISSUED 326 PM EST WED DEC 17 2014

SHORT TERM...THROUGH TONIGHT

STRONG UPPER WAVE EMBEDDED WITHIN THE LONGWAVE TROUGH OVER THE GREAT
LAKES AND NEW ENGLAND WILL MOVE ACROSS LOWER MICHIGAN THIS AFTERNOON
AND EARLY EVENING. THIS WILL DRAG AN AREA OF MID-LEVEL DEFORMATION
DOWN ACROSS NORTHERN AND CENTRAL MICHIGAN AS IT TRACKS EAST THROUGH
THE AREA...AND ALSO PULL A SURFACE TROUGH NOW EXTENDING BACK FROM
THE MAIN LOW CENTER OVER SOUTHERN ONTARIO/QUEBEC DOWN INTO CENTRAL
MICHIGAN.

CURRENTLY...WIDESPREAD SNOW SHOWERS ARE DEVELOPING OVER NORTHERN
LOWER MICHIGAN WITHIN THE AREA OF DEFORMATION...DEEPER MOISTURE TO
SATURATE THE DENDRITIC GROWTH ZONE...AND AHEAD OF THE TROUGH AXIS.
ACTIVITY IS ALSO GETTING A BOOST FROM MOISTURE FLUX OFF LAKE
MICHIGAN. AREA OF BETTER FORCING AND DEEPER MOISTURE LOOKS TO JUST
CLIP THE SAGINAW VALLEY AND THUMB FROM LATE THIS AFTERNOON THROUGH
ABOUT 9 PM...WITH LIFT WEAKENING AND STEEPER LAPSE RATES FROM THE
UPPER COLD POOL SHIFTING EAST WITH THE UPPER LOW AND SURFACE TROUGH
TONIGHT. THIS SHOULD PREVENT ACTIVITY FROM SEEPING FURTHER
SOUTH...AND KEEP THE REMAINDER OF THE NIGHT FAIRLY QUIET OUTSIDE OF
SOME POTENTIAL FOR LIGHT LAKE EFFECT BANDS TO BRUSH THE THUMB. SNOW
AMOUNTS OVER THE SAGINAW VALLEY AND NORTHERN THUMB SHOULD BE FAIRLY
LIGHT GIVEN ONLY 1 G/KG OF SPECIFIC HUMIDITY AND WEAKENING
FORCING...WITH AMOUNTS EXPECTED TO TOP OUT AROUND 0.5 INCHES.

FURTHER SOUTH THIS EVENING...LAKE EFFECT PROCESSES FROM OFF LAKE
MICHIGAN WILL CONTINUE TO BRING THE CHANCE FOR FLURRIES OR EVEN A
LIGHT SNOW SHOWER THIS EVENING BEFORE DRIER AIR ARRIVES AND THE EXIT
OF THE UPPER COLD POOL ALLOWS LAPSE RATES TO BECOME MORE STABLE.
BEST POTENTIAL WILL BE BEFORE 8 PM...AS UPPER COLD POOL BRIEFLY
STEEPENS LAPSE RATES.

CLOUDS ARE EXPECTED TO REMAIN LOCKED INTO PLACE TONIGHT UNDER AN
INVERSION. THIS SHOULD PREVENT TEMPERATURES FROM FALLING TOO FAR
TONIGHT...WITH MINS IN THE MID 20S EXPECTED.

LONG TERM...THURSDAY THROUGH TUESDAY

THE END OF THE WEEK WILL REMAIN RELATIVELY QUIET AS HIGH PRESSURE
BUILDS IN OVER THE REGION BEHIND THE EXITING SURFACE TROUGH.
NORTHERLY FLOW WILL SLACKEN AS THE GRADIENT RELAXES AND DRIER AIR
FILTERS IN FROM THE NORTH.  THE ONE ISSUE EARLY ON IN THE EXTENDED
IS THE CHANCE FOR SOME LINGERING SNOW SHOWERS OVER THE THUMB AREA
WITH THE NORTHERLY FLOW...ESPECIALLY THURSDAY MORNING.  LATEST MODEL
RUNS SHOWED WEAKENING OF THE GRADIENT AND WITH DRIER AIR MOVING IN
HAVE DECREASED POPS WHILE LEAVING IN A MENTION OF FLURRIES THROUGH
THURSDAY NIGHT.  CONTINUED CLOUDY CONDITIONS WILL BE SEEN THROUGH THE
DAY ON THURSDAY BEFORE SKIES ARE EXPECTED TO SLIGHTLY IMPROVE
FRIDAY.  HOWEVER...GIVEN THIS TIME OF YEAR WOULD NOT BE SURPRISED IF
LOW CLOUDS REMAINED WHICH HAS BEEN THE CASE LATELY.

ALL SIGNS STILL POINT TO A QUIET WEEKEND AS ASCENT FROM
DEAMPLIFYING WAVE IS STILL SHOWN BY NWP SOLUTIONS TO PASS WELL TO
OUR SOUTH. CONTINUED DRY AND A BIT WARMER MONDAY AHEAD OF A CLIPPER
TYPE SYSTEM ORGANIZING OVER THE NORTHERN PLAINS. REMAINDER OF THE
FORECAST THROUGH CHRISTMAS EVE WILL HINGE UPON VERY STRONG PAC NW
JET ENERGY CARVING OUT A DEEP LONGWAVE TROUGH OVER THE CENTRAL
CONUS. INDICATIONS ARE THAT THE CLIPPER WILL SLOW IN RESPONSE TO
THIS JET ENERGY AND EVENTUALLY BE ABSORBED INTO A STRONGER SURFACE
LOW LIFTING INTO THE GREAT LAKES FROM THE DEEP SOUTH. 12Z MODELS
INDICATE THE CYCLONE BECOMING QUITE DEEP BY THE TIME IT REACHES OUR
AREA. DETAILS IN TERMS OF PRECIP TYPE WILL DEPEND ON THE LOW
TRACK...WITH LOW CONFIDENCE AT THIS POINT...BUT CURRENT INDICATIONS
ARE THAT IMPACTFUL WEATHER WILL BECOME MORE LIKELY TOWARD CHRISTMAS
EVE.

MARINE...

GUSTY WINDS ON WEDNESDAY WILL EVENTUALLY SLACKEN AS A LOW PRESSURE
SYSTEM AND ASSOCIATED SURFACE TROUGH PUSH TO THE EAST OVERNIGHT.
SNOW SHOWERS ARE ALSO POSSIBLE THROUGH THE EVENING AS THE TROUGH
SWINGS THROUGH. AS WESTERLY/NORTHWESTERLY FLOW IS MAINTAINED THROUGH
THE OVERNIGHT HOURS...THE SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY
ALONG WITH LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH WILL BE
CONTINUED.  HIGH PRESSURE THEN BUILDS IN ON THURSDAY WHICH WILL
BRING LIGHTER NORTHERLY WINDS TO THE MARINE AREAS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....99
SHORT TERM...HLO
LONG TERM....SS/DT
MARINE.......SS


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 172026
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
326 PM EST WED DEC 17 2014

.SHORT TERM...THROUGH TONIGHT

STRONG UPPER WAVE EMBEDDED WITHIN THE LONGWAVE TROUGH OVER THE GREAT
LAKES AND NEW ENGLAND WILL MOVE ACROSS LOWER MICHIGAN THIS AFTERNOON
AND EARLY EVENING. THIS WILL DRAG AN AREA OF MID-LEVEL DEFORMATION
DOWN ACROSS NORTHERN AND CENTRAL MICHIGAN AS IT TRACKS EAST THROUGH
THE AREA...AND ALSO PULL A SURFACE TROUGH NOW EXTENDING BACK FROM
THE MAIN LOW CENTER OVER SOUTHERN ONTARIO/QUEBEC DOWN INTO CENTRAL
MICHIGAN.

CURRENTLY...WIDESPREAD SNOW SHOWERS ARE DEVELOPING OVER NORTHERN
LOWER MICHIGAN WITHIN THE AREA OF DEFORMATION...DEEPER MOISTURE TO
SATURATE THE DENDRITIC GROWTH ZONE...AND AHEAD OF THE TROUGH AXIS.
ACTIVITY IS ALSO GETTING A BOOST FROM MOISTURE FLUX OFF LAKE
MICHIGAN. AREA OF BETTER FORCING AND DEEPER MOISTURE LOOKS TO JUST
CLIP THE SAGINAW VALLEY AND THUMB FROM LATE THIS AFTERNOON THROUGH
ABOUT 9 PM...WITH LIFT WEAKENING AND STEEPER LAPSE RATES FROM THE
UPPER COLD POOL SHIFTING EAST WITH THE UPPER LOW AND SURFACE TROUGH
TONIGHT. THIS SHOULD PREVENT ACTIVITY FROM SEEPING FURTHER
SOUTH...AND KEEP THE REMAINDER OF THE NIGHT FAIRLY QUIET OUTSIDE OF
SOME POTENTIAL FOR LIGHT LAKE EFFECT BANDS TO BRUSH THE THUMB. SNOW
AMOUNTS OVER THE SAGINAW VALLEY AND NORTHERN THUMB SHOULD BE FAIRLY
LIGHT GIVEN ONLY 1 G/KG OF SPECIFIC HUMIDITY AND WEAKENING
FORCING...WITH AMOUNTS EXPECTED TO TOP OUT AROUND 0.5 INCHES.

FURTHER SOUTH THIS EVENING...LAKE EFFECT PROCESSES FROM OFF LAKE
MICHIGAN WILL CONTINUE TO BRING THE CHANCE FOR FLURRIES OR EVEN A
LIGHT SNOW SHOWER THIS EVENING BEFORE DRIER AIR ARRIVES AND THE EXIT
OF THE UPPER COLD POOL ALLOWS LAPSE RATES TO BECOME MORE STABLE.
BEST POTENTIAL WILL BE BEFORE 8 PM...AS UPPER COLD POOL BRIEFLY
STEEPENS LAPSE RATES.

CLOUDS ARE EXPECTED TO REMAIN LOCKED INTO PLACE TONIGHT UNDER AN
INVERSION. THIS SHOULD PREVENT TEMPERATURES FROM FALLING TOO FAR
TONIGHT...WITH MINS IN THE MID 20S EXPECTED.

&&

.LONG TERM...THURSDAY THROUGH TUESDAY

THE END OF THE WEEK WILL REMAIN RELATIVELY QUIET AS HIGH PRESSURE
BUILDS IN OVER THE REGION BEHIND THE EXITING SURFACE TROUGH.
NORTHERLY FLOW WILL SLACKEN AS THE GRADIENT RELAXES AND DRIER AIR
FILTERS IN FROM THE NORTH.  THE ONE ISSUE EARLY ON IN THE EXTENDED
IS THE CHANCE FOR SOME LINGERING SNOW SHOWERS OVER THE THUMB AREA
WITH THE NORTHERLY FLOW...ESPECIALLY THURSDAY MORNING.  LATEST MODEL
RUNS SHOWED WEAKENING OF THE GRADIENT AND WITH DRIER AIR MOVING IN
HAVE DECREASED POPS WHILE LEAVING IN A MENTION OF FLURRIES THROUGH
THURSDAY NIGHT.  CONTINUED CLOUDY CONDITIONS WILL BE SEEN THROUGH THE
DAY ON THURSDAY BEFORE SKIES ARE EXPECTED TO SLIGHTLY IMPROVE
FRIDAY.  HOWEVER...GIVEN THIS TIME OF YEAR WOULD NOT BE SURPRISED IF
LOW CLOUDS REMAINED WHICH HAS BEEN THE CASE LATELY.

ALL SIGNS STILL POINT TO A QUIET WEEKEND AS ASCENT FROM
DEAMPLIFYING WAVE IS STILL SHOWN BY NWP SOLUTIONS TO PASS WELL TO
OUR SOUTH. CONTINUED DRY AND A BIT WARMER MONDAY AHEAD OF A CLIPPER
TYPE SYSTEM ORGANIZING OVER THE NORTHERN PLAINS. REMAINDER OF THE
FORECAST THROUGH CHRISTMAS EVE WILL HINGE UPON VERY STRONG PAC NW
JET ENERGY CARVING OUT A DEEP LONGWAVE TROUGH OVER THE CENTRAL
CONUS. INDICATIONS ARE THAT THE CLIPPER WILL SLOW IN RESPONSE TO
THIS JET ENERGY AND EVENTUALLY BE ABSORBED INTO A STRONGER SURFACE
LOW LIFTING INTO THE GREAT LAKES FROM THE DEEP SOUTH. 12Z MODELS
INDICATE THE CYCLONE BECOMING QUITE DEEP BY THE TIME IT REACHES OUR
AREA. DETAILS IN TERMS OF PRECIP TYPE WILL DEPEND ON THE LOW
TRACK...WITH LOW CONFIDENCE AT THIS POINT...BUT CURRENT INDICATIONS
ARE THAT IMPACTFUL WEATHER WILL BECOME MORE LIKELY TOWARD CHRISTMAS
EVE.

&&

.MARINE...

GUSTY WINDS ON WEDNESDAY WILL EVENTUALLY SLACKEN AS A LOW PRESSURE
SYSTEM AND ASSOCIATED SURFACE TROUGH PUSH TO THE EAST OVERNIGHT.
SNOW SHOWERS ARE ALSO POSSIBLE THROUGH THE EVENING AS THE TROUGH
SWINGS THROUGH. AS WESTERLY/NORTHWESTERLY FLOW IS MAINTAINED THROUGH
THE OVERNIGHT HOURS...THE SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY
ALONG WITH LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH WILL BE
CONTINUED.  HIGH PRESSURE THEN BUILDS IN ON THURSDAY WHICH WILL
BRING LIGHTER NORTHERLY WINDS TO THE MARINE AREAS.

&&

.AVIATION...ISSUED 1229 PM EST WED DEC 17 2014

//DISCUSSION...MOISTURE WILL REMAIN LOCKED UNDER AN INVERSION
THIS AFTERNOON...RESULTING IN OVERCAST SKIES THAT GRADUALLY RISE
FROM MVFR TO VFR DURING THE LATE AFTERNOON AND EVENING AS THE
MIXED LAYER INCREASES IN DEPTH AND SOME DRIER AIR TRIES TO WORK
IN. TIMING OF WHEN CEILINGS WILL RISE ABOVE 3000 FEET IS UNCERTAIN
HOWEVER...AS FLOW OFF LAKE MICHIGAN ADDS SOME ADDITIONAL LOW-LEVEL
MOISTURE. THE BEST CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS WILL
BE NORTH OF DET. AS FLOW TURNS MORE NORTHWESTERLY TONIGHT AND LAKE
EFFECT BECOMES LESS FAVORABLE...A FEW BREAKS IN THE CLOUDS ARE
EXPECTED. CEILINGS SHOULD THEN LOWER BACK TO MVFR AFTER MIDNIGHT
AS INVERSION HEIGHTS LOWER AND A SURFACE TROUGH DROPS DOWN FROM
NORTHERN MICHIGAN.

WESTERLY GUSTS TO AROUND 25 KNOTS WILL GRADUALLY TAPER OFF DURING
THE LATE AFTERNOON AND EVENING AS LOW PRESSURE OVER SOUTHERN ONTARIO
AND QUEBEC CONTINUES TO MOVE AWAY FROM THE AREA...WEAKENING THE
SURFACE PRESSURE GRADIENT.

FOR DTW...WESTERLY GUSTS BETWEEN 20 AND 25 KNOTS WILL CONTINUE
THROUGH THE AFTERNOON BEFORE SUBSIDING IN THE EVENING. A FEW STRAY
SNOWFLAKES ARE STILL POSSIBLE TODAY...BUT SHOWERS ARE EXPECTED TO
REMAIN NORTH OF DTW. CEILINGS ARE EXPECTED TO RISE TO VFR FOR THE
EVENING BEFORE DROPPING BACK DOWN TO MVFR AFTER MIDNIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LHZ422-442-
     443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

SHORT TERM...HLO
LONG TERM....SS/DT
MARINE.......SS
AVIATION.....HLO


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 172026
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
326 PM EST WED DEC 17 2014

.SHORT TERM...THROUGH TONIGHT

STRONG UPPER WAVE EMBEDDED WITHIN THE LONGWAVE TROUGH OVER THE GREAT
LAKES AND NEW ENGLAND WILL MOVE ACROSS LOWER MICHIGAN THIS AFTERNOON
AND EARLY EVENING. THIS WILL DRAG AN AREA OF MID-LEVEL DEFORMATION
DOWN ACROSS NORTHERN AND CENTRAL MICHIGAN AS IT TRACKS EAST THROUGH
THE AREA...AND ALSO PULL A SURFACE TROUGH NOW EXTENDING BACK FROM
THE MAIN LOW CENTER OVER SOUTHERN ONTARIO/QUEBEC DOWN INTO CENTRAL
MICHIGAN.

CURRENTLY...WIDESPREAD SNOW SHOWERS ARE DEVELOPING OVER NORTHERN
LOWER MICHIGAN WITHIN THE AREA OF DEFORMATION...DEEPER MOISTURE TO
SATURATE THE DENDRITIC GROWTH ZONE...AND AHEAD OF THE TROUGH AXIS.
ACTIVITY IS ALSO GETTING A BOOST FROM MOISTURE FLUX OFF LAKE
MICHIGAN. AREA OF BETTER FORCING AND DEEPER MOISTURE LOOKS TO JUST
CLIP THE SAGINAW VALLEY AND THUMB FROM LATE THIS AFTERNOON THROUGH
ABOUT 9 PM...WITH LIFT WEAKENING AND STEEPER LAPSE RATES FROM THE
UPPER COLD POOL SHIFTING EAST WITH THE UPPER LOW AND SURFACE TROUGH
TONIGHT. THIS SHOULD PREVENT ACTIVITY FROM SEEPING FURTHER
SOUTH...AND KEEP THE REMAINDER OF THE NIGHT FAIRLY QUIET OUTSIDE OF
SOME POTENTIAL FOR LIGHT LAKE EFFECT BANDS TO BRUSH THE THUMB. SNOW
AMOUNTS OVER THE SAGINAW VALLEY AND NORTHERN THUMB SHOULD BE FAIRLY
LIGHT GIVEN ONLY 1 G/KG OF SPECIFIC HUMIDITY AND WEAKENING
FORCING...WITH AMOUNTS EXPECTED TO TOP OUT AROUND 0.5 INCHES.

FURTHER SOUTH THIS EVENING...LAKE EFFECT PROCESSES FROM OFF LAKE
MICHIGAN WILL CONTINUE TO BRING THE CHANCE FOR FLURRIES OR EVEN A
LIGHT SNOW SHOWER THIS EVENING BEFORE DRIER AIR ARRIVES AND THE EXIT
OF THE UPPER COLD POOL ALLOWS LAPSE RATES TO BECOME MORE STABLE.
BEST POTENTIAL WILL BE BEFORE 8 PM...AS UPPER COLD POOL BRIEFLY
STEEPENS LAPSE RATES.

CLOUDS ARE EXPECTED TO REMAIN LOCKED INTO PLACE TONIGHT UNDER AN
INVERSION. THIS SHOULD PREVENT TEMPERATURES FROM FALLING TOO FAR
TONIGHT...WITH MINS IN THE MID 20S EXPECTED.

&&

.LONG TERM...THURSDAY THROUGH TUESDAY

THE END OF THE WEEK WILL REMAIN RELATIVELY QUIET AS HIGH PRESSURE
BUILDS IN OVER THE REGION BEHIND THE EXITING SURFACE TROUGH.
NORTHERLY FLOW WILL SLACKEN AS THE GRADIENT RELAXES AND DRIER AIR
FILTERS IN FROM THE NORTH.  THE ONE ISSUE EARLY ON IN THE EXTENDED
IS THE CHANCE FOR SOME LINGERING SNOW SHOWERS OVER THE THUMB AREA
WITH THE NORTHERLY FLOW...ESPECIALLY THURSDAY MORNING.  LATEST MODEL
RUNS SHOWED WEAKENING OF THE GRADIENT AND WITH DRIER AIR MOVING IN
HAVE DECREASED POPS WHILE LEAVING IN A MENTION OF FLURRIES THROUGH
THURSDAY NIGHT.  CONTINUED CLOUDY CONDITIONS WILL BE SEEN THROUGH THE
DAY ON THURSDAY BEFORE SKIES ARE EXPECTED TO SLIGHTLY IMPROVE
FRIDAY.  HOWEVER...GIVEN THIS TIME OF YEAR WOULD NOT BE SURPRISED IF
LOW CLOUDS REMAINED WHICH HAS BEEN THE CASE LATELY.

ALL SIGNS STILL POINT TO A QUIET WEEKEND AS ASCENT FROM
DEAMPLIFYING WAVE IS STILL SHOWN BY NWP SOLUTIONS TO PASS WELL TO
OUR SOUTH. CONTINUED DRY AND A BIT WARMER MONDAY AHEAD OF A CLIPPER
TYPE SYSTEM ORGANIZING OVER THE NORTHERN PLAINS. REMAINDER OF THE
FORECAST THROUGH CHRISTMAS EVE WILL HINGE UPON VERY STRONG PAC NW
JET ENERGY CARVING OUT A DEEP LONGWAVE TROUGH OVER THE CENTRAL
CONUS. INDICATIONS ARE THAT THE CLIPPER WILL SLOW IN RESPONSE TO
THIS JET ENERGY AND EVENTUALLY BE ABSORBED INTO A STRONGER SURFACE
LOW LIFTING INTO THE GREAT LAKES FROM THE DEEP SOUTH. 12Z MODELS
INDICATE THE CYCLONE BECOMING QUITE DEEP BY THE TIME IT REACHES OUR
AREA. DETAILS IN TERMS OF PRECIP TYPE WILL DEPEND ON THE LOW
TRACK...WITH LOW CONFIDENCE AT THIS POINT...BUT CURRENT INDICATIONS
ARE THAT IMPACTFUL WEATHER WILL BECOME MORE LIKELY TOWARD CHRISTMAS
EVE.

&&

.MARINE...

GUSTY WINDS ON WEDNESDAY WILL EVENTUALLY SLACKEN AS A LOW PRESSURE
SYSTEM AND ASSOCIATED SURFACE TROUGH PUSH TO THE EAST OVERNIGHT.
SNOW SHOWERS ARE ALSO POSSIBLE THROUGH THE EVENING AS THE TROUGH
SWINGS THROUGH. AS WESTERLY/NORTHWESTERLY FLOW IS MAINTAINED THROUGH
THE OVERNIGHT HOURS...THE SMALL CRAFT ADVISORY FOR OUTER SAGINAW BAY
ALONG WITH LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH WILL BE
CONTINUED.  HIGH PRESSURE THEN BUILDS IN ON THURSDAY WHICH WILL
BRING LIGHTER NORTHERLY WINDS TO THE MARINE AREAS.

&&

.AVIATION...ISSUED 1229 PM EST WED DEC 17 2014

//DISCUSSION...MOISTURE WILL REMAIN LOCKED UNDER AN INVERSION
THIS AFTERNOON...RESULTING IN OVERCAST SKIES THAT GRADUALLY RISE
FROM MVFR TO VFR DURING THE LATE AFTERNOON AND EVENING AS THE
MIXED LAYER INCREASES IN DEPTH AND SOME DRIER AIR TRIES TO WORK
IN. TIMING OF WHEN CEILINGS WILL RISE ABOVE 3000 FEET IS UNCERTAIN
HOWEVER...AS FLOW OFF LAKE MICHIGAN ADDS SOME ADDITIONAL LOW-LEVEL
MOISTURE. THE BEST CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS WILL
BE NORTH OF DET. AS FLOW TURNS MORE NORTHWESTERLY TONIGHT AND LAKE
EFFECT BECOMES LESS FAVORABLE...A FEW BREAKS IN THE CLOUDS ARE
EXPECTED. CEILINGS SHOULD THEN LOWER BACK TO MVFR AFTER MIDNIGHT
AS INVERSION HEIGHTS LOWER AND A SURFACE TROUGH DROPS DOWN FROM
NORTHERN MICHIGAN.

WESTERLY GUSTS TO AROUND 25 KNOTS WILL GRADUALLY TAPER OFF DURING
THE LATE AFTERNOON AND EVENING AS LOW PRESSURE OVER SOUTHERN ONTARIO
AND QUEBEC CONTINUES TO MOVE AWAY FROM THE AREA...WEAKENING THE
SURFACE PRESSURE GRADIENT.

FOR DTW...WESTERLY GUSTS BETWEEN 20 AND 25 KNOTS WILL CONTINUE
THROUGH THE AFTERNOON BEFORE SUBSIDING IN THE EVENING. A FEW STRAY
SNOWFLAKES ARE STILL POSSIBLE TODAY...BUT SHOWERS ARE EXPECTED TO
REMAIN NORTH OF DTW. CEILINGS ARE EXPECTED TO RISE TO VFR FOR THE
EVENING BEFORE DROPPING BACK DOWN TO MVFR AFTER MIDNIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LHZ422-442-
     443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

SHORT TERM...HLO
LONG TERM....SS/DT
MARINE.......SS
AVIATION.....HLO


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 171729
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1229 PM EST WED DEC 17 2014


.AVIATION...

//DISCUSSION...MOISTURE WILL REMAIN LOCKED UNDER AN INVERSION
THIS AFTERNOON...RESULTING IN OVERCAST SKIES THAT GRADUALLY RISE
FROM MVFR TO VFR DURING THE LATE AFTERNOON AND EVENING AS THE
MIXED LAYER INCREASES IN DEPTH AND SOME DRIER AIR TRIES TO WORK
IN. TIMING OF WHEN CEILINGS WILL RISE ABOVE 3000 FEET IS UNCERTAIN
HOWEVER...AS FLOW OFF LAKE MICHIGAN ADDS SOME ADDITIONAL LOW-LEVEL
MOISTURE. THE BEST CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS WILL
BE NORTH OF DET. AS FLOW TURNS MORE NORTHWESTERLY TONIGHT AND LAKE
EFFECT BECOMES LESS FAVORABLE...A FEW BREAKS IN THE CLOUDS ARE
EXPECTED. CEILINGS SHOULD THEN LOWER BACK TO MVFR AFTER MIDNIGHT
AS INVERSION HEIGHTS LOWER AND A SURFACE TROUGH DROPS DOWN FROM
NORTHERN MICHIGAN.

WESTERLY GUSTS TO AROUND 25 KNOTS WILL GRADUALLY TAPER OFF DURING
THE LATE AFTERNOON AND EVENING AS LOW PRESSURE OVER SOUTHERN ONTARIO
AND QUEBEC CONTINUES TO MOVE AWAY FROM THE AREA...WEAKENING THE
SURFACE PRESSURE GRADIENT.

FOR DTW...WESTERLY GUSTS BETWEEN 20 AND 25 KNOTS WILL CONTINUE
THROUGH THE AFTERNOON BEFORE SUBSIDING IN THE EVENING. A FEW STRAY
SNOWFLAKES ARE STILL POSSIBLE TODAY...BUT SHOWERS ARE EXPECTED TO
REMAIN NORTH OF DTW. CEILINGS ARE EXPECTED TO RISE TO VFR FOR THE
EVENING BEFORE DROPPING BACK DOWN TO MVFR AFTER MIDNIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.PREV DISCUSSION...ISSUED 350 AM EST WED DEC 17 2014

SHORT TERM... TODAY AND TONIGHT

AFTER 3 DAYS OF MAX TEMPERATURES IN THE 40S AND LOWER 50S...NORMAL
DECEMBER AIR IS SURGING BACK INTO SE MICHIGAN FOR TODAY. THIS WILL
LIMIT HIGH TEMPERATURES TO THE LOWER AND MID 30S LEADING INTO LOWS
TONIGHT IN THE MID 20S. LIGHT SNOW WILL LINGER NEAR THE TRI CITIES
AND NORTHERN THUMB...MAINLY DURING THE MORNING...WITH LITTLE MORE
THAN A FLURRY OVER THE REST OF SE MICHIGAN.

LIGHT SNOW ONGOING OVER THE SAGINAW VALLEY AND NORTHERN THUMB BEFORE
SUNRISE IS TIED TO AN AXIS OF DEFORMATION IN THE LOW TO MID LEVELS.
THIS FORCING WILL CONTINUE TO SHEAR INTO MORE OF A WEST TO EAST
ORIENTATION DURING THE MORNING WITH THE STRONGEST DYNAMIC FORCING
DISPLACED FROM THE MOISTURE AXIS. THIS WILL MAINTAIN STEADY BUT
LIGHT PRECIPITATION OVER THE NORTHERN GREAT LAKES AND LEAVE THE TRI
CITIES AND NORTHERN THUMB ON THE SOUTHERN FRINGE OF THE PATTERN. AT
THE SAME TIME...DRY AIR WILL CONTINUE TO SLIDE OVER THE REST OF SE
MICHIGAN AS STRONG SUBSIDENCE OCCURS BETWEEN THE DEFORMATION AXIS
ASSOCIATED WITH THE TRAILING UPPER TROUGH AND NORTH FLANK OF THE
UPPER JET AXIS THAT IS CENTERED WELL SOUTH OF THE GREAT LAKES. THIS
WILL ONLY ALLOW WEAK LAKE MICHIGAN ACTIVATION WHICH WILL STRUGGLE TO
MOVE THIS FAR EAST IN ANY FORM GREATER THAN FLURRIES WHILE THE LOW
LEVEL THERMAL TROUGH IS OVERHEAD.

THE UPPER TROUGH WILL SLIDE QUICKLY EASTWARD BY TONIGHT AND LEAVE
TRAILING CYCLONIC OVERHEAD THAT WILL ALLOW A MODEST UPTICK IN
ACTIVITY OFF LAKE MICHIGAN AND HURON EARLY BEFORE WARMER AIR BEGINS
TO MOVE OVER THE SOUTHERN GREAT LAKES. THERE IS GOOD MODEL AGREEMENT
INDICATING 850 MB TEMPERATURE WARMING FROM NEAR -13C AT MID
AFTERNOON TO THE -8C TO -6C RANGE AFTER MIDNIGHT. BOTH THIS AND THE
GENERAL VEERING OF THE LOW LEVEL FLOW WILL KEEP LAKE EFFECT SNOW
SHOWERS OVER SW LOWER AND NORTHERN INDIANA AND PERHAPS JUST BRUSHING
THE NORTHERN THUMB TONIGHT.

LONG TERM...THURSDAY THROUGH TUESDAY

THE ONLY REAL CONCERN ON THURSDAY WILL BE THE LAKE EFFECT SNOW
SHOWERS BRUSHING THE EASTERN THUMB WITH A NORTH NORTHWEST FLOW OFF
LAKE HURON. WHILE THIS TRAJECTORY IS FAVORABLE FOR SNOWFALL OVER
CANADA...THERE APPEARS TO BE ENOUGH OF A FAVORABLE COMPONENT TO THE
WIND DIRECTION TO MAINTAIN THE CHANCY POPS INHERITED BY THE PREVIOUS
FORECAST. WITH THE MOSTLY UNFAVORABLE TRAJECTORY SNOWFALL
AMOUNTS...IF THERE ARE ANY...WILL BE FAIRLY LIGHT WITH A FEW TENTHS
OF AN INCH POSSIBLE.  HIGH PRESSURE THEN BUILDS IN ACROSS THE GREAT
LAKES REGION ON FRIDAY AS THE MOS GUIDANCE SUGGESTS CLEARING SKIES
LATE THURSDAY NIGHT AND INTO FRIDAY. HOWEVER MODEL SOUNDINGS
INDICATE SUBSIDENCE FROM THE HIGH WILL ONCE AGAIN TRAP MOISTURE
BETWEEN 900 AND 950 MB WHICH WILL MEAN LOW STRATUS WILL ONCE AGAIN
PLAGUE THE CENTRAL GREAT LAKES REGION.  THEREFORE BACKED OFF ON THE
CLEARING SKIES DURING THIS PERIOD AND WENT MORE PESSIMISTIC THAN THE
PREVIOUS FORECAST.

THIS HIGH WILL KEEP THE CENTRAL GREAT LAKES DRY DURING THE WEEKEND
AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE SOUTHEASTERN CONUS.
ALTHOUGH THE SUPER BLEND PAINTS CHANCY POPS ACROSS MUCH OF THE
CWA...MAINLY SATURDAY AND SATURDAY NIGHT...THE NWP MODELS KEEP
THINGS DRY WITH THE AFOREMENTIONED DRY HIGH PRESSURE IN PLACE.
GIVEN THE WET BIAS OF THE SUPER BLEND WILL REMOVE POPS DURING THE
WEEKEND AND GO WITH A DRY FORECAST.  NEAR NORMAL TEMPERATURES ARE
EXPECTED DURING THIS TIME WITH HIGHS IN THE LOW TO MID 30S AND LOWS
IN THE MIDDLE TO UPPER 20S.

THE NEXT SYSTEM OF CONSEQUENCE DEVELOPS OVER THE NORTHERN PLAINS ON
MONDAY AND TRACKS OVER THE WESTERN GREAT LAKES ON TUESDAY.  THIS
SYSTEM LOOKS TO HAVE FAIRLY GOOD DYNAMICS WITH A DEEP 500 MB TROUGH
AND A DECENT LOW LEVEL JET.  IT LOOKS LIKE SOUTHEAST MICHIGAN WILL
BE ON THE WARM SIDE OF THIS SYSTEM ON TUESDAY...WITH MAINLY LIQUID
PRECIPITATION EXPECTED AT THIS POINT IN THE FORECAST.

MARINE...

COLD AIR ADVECTION AND STRONG WESTERLY WINDS ARE INCREASING IN THE
WAKE OF A COLD FRONT THAT PASSED THROUGH THE CENTRAL GREAT LAKES
EARLY THIS MORNING. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO
THE STRONGEST FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT
THAT LEVEL. IT SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS
DOWN THOUGH WITH SUSTAINED FLOW PUSHING 20 KNOTS. WILL CONTINUE
SMALL CRAFT ADVISORIES FOR ALL NEARSHORE ZONES FOR THESE ELEVATED
WINDS. WAVES WILL ALSO REACH CRITERIA IN SOME OF THE LAKE HURON
ZONES BUT OFFSHORE FLOW WILL KEEP WAVE HEIGHTS DOWN SOMEWHAT ALONG
WITH SOME ICE COVER SHOWING UP IN INNER SAGINAW BAY. WINDS WILL
DECREASE BELOW CRITERIA THIS AFTERNOON BUT WILL STAY ELEVATED
THROUGH TONIGHT AS THEY VEER TO THE NORTHWEST. ALTHOUGH WINDS WILL
FALL BELOW CRITERIA...THE CONTINUED FETCH OFF LAKE HURON WITH THE
NORTHWEST WINDS WILL MAINTAIN HIGHER WAVES THROUGH TONIGHT ACROSS
OUTER SAGINAW BAY AND LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH.
WINDS AND WAVES WILL CONTINUE TO SLOWLY CALM AS HIGH PRESSURE
BUILDS IN ACROSS THE CENTRAL GREAT LAKES THURSDAY AND FRIDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LHZ422-442-
     443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

AVIATION.....HLO
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 171729
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1229 PM EST WED DEC 17 2014


.AVIATION...

//DISCUSSION...MOISTURE WILL REMAIN LOCKED UNDER AN INVERSION
THIS AFTERNOON...RESULTING IN OVERCAST SKIES THAT GRADUALLY RISE
FROM MVFR TO VFR DURING THE LATE AFTERNOON AND EVENING AS THE
MIXED LAYER INCREASES IN DEPTH AND SOME DRIER AIR TRIES TO WORK
IN. TIMING OF WHEN CEILINGS WILL RISE ABOVE 3000 FEET IS UNCERTAIN
HOWEVER...AS FLOW OFF LAKE MICHIGAN ADDS SOME ADDITIONAL LOW-LEVEL
MOISTURE. THE BEST CHANCE FOR FLURRIES OR LIGHT SNOW SHOWERS WILL
BE NORTH OF DET. AS FLOW TURNS MORE NORTHWESTERLY TONIGHT AND LAKE
EFFECT BECOMES LESS FAVORABLE...A FEW BREAKS IN THE CLOUDS ARE
EXPECTED. CEILINGS SHOULD THEN LOWER BACK TO MVFR AFTER MIDNIGHT
AS INVERSION HEIGHTS LOWER AND A SURFACE TROUGH DROPS DOWN FROM
NORTHERN MICHIGAN.

WESTERLY GUSTS TO AROUND 25 KNOTS WILL GRADUALLY TAPER OFF DURING
THE LATE AFTERNOON AND EVENING AS LOW PRESSURE OVER SOUTHERN ONTARIO
AND QUEBEC CONTINUES TO MOVE AWAY FROM THE AREA...WEAKENING THE
SURFACE PRESSURE GRADIENT.

FOR DTW...WESTERLY GUSTS BETWEEN 20 AND 25 KNOTS WILL CONTINUE
THROUGH THE AFTERNOON BEFORE SUBSIDING IN THE EVENING. A FEW STRAY
SNOWFLAKES ARE STILL POSSIBLE TODAY...BUT SHOWERS ARE EXPECTED TO
REMAIN NORTH OF DTW. CEILINGS ARE EXPECTED TO RISE TO VFR FOR THE
EVENING BEFORE DROPPING BACK DOWN TO MVFR AFTER MIDNIGHT.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH THE TAF PERIOD.

&&

.PREV DISCUSSION...ISSUED 350 AM EST WED DEC 17 2014

SHORT TERM... TODAY AND TONIGHT

AFTER 3 DAYS OF MAX TEMPERATURES IN THE 40S AND LOWER 50S...NORMAL
DECEMBER AIR IS SURGING BACK INTO SE MICHIGAN FOR TODAY. THIS WILL
LIMIT HIGH TEMPERATURES TO THE LOWER AND MID 30S LEADING INTO LOWS
TONIGHT IN THE MID 20S. LIGHT SNOW WILL LINGER NEAR THE TRI CITIES
AND NORTHERN THUMB...MAINLY DURING THE MORNING...WITH LITTLE MORE
THAN A FLURRY OVER THE REST OF SE MICHIGAN.

LIGHT SNOW ONGOING OVER THE SAGINAW VALLEY AND NORTHERN THUMB BEFORE
SUNRISE IS TIED TO AN AXIS OF DEFORMATION IN THE LOW TO MID LEVELS.
THIS FORCING WILL CONTINUE TO SHEAR INTO MORE OF A WEST TO EAST
ORIENTATION DURING THE MORNING WITH THE STRONGEST DYNAMIC FORCING
DISPLACED FROM THE MOISTURE AXIS. THIS WILL MAINTAIN STEADY BUT
LIGHT PRECIPITATION OVER THE NORTHERN GREAT LAKES AND LEAVE THE TRI
CITIES AND NORTHERN THUMB ON THE SOUTHERN FRINGE OF THE PATTERN. AT
THE SAME TIME...DRY AIR WILL CONTINUE TO SLIDE OVER THE REST OF SE
MICHIGAN AS STRONG SUBSIDENCE OCCURS BETWEEN THE DEFORMATION AXIS
ASSOCIATED WITH THE TRAILING UPPER TROUGH AND NORTH FLANK OF THE
UPPER JET AXIS THAT IS CENTERED WELL SOUTH OF THE GREAT LAKES. THIS
WILL ONLY ALLOW WEAK LAKE MICHIGAN ACTIVATION WHICH WILL STRUGGLE TO
MOVE THIS FAR EAST IN ANY FORM GREATER THAN FLURRIES WHILE THE LOW
LEVEL THERMAL TROUGH IS OVERHEAD.

THE UPPER TROUGH WILL SLIDE QUICKLY EASTWARD BY TONIGHT AND LEAVE
TRAILING CYCLONIC OVERHEAD THAT WILL ALLOW A MODEST UPTICK IN
ACTIVITY OFF LAKE MICHIGAN AND HURON EARLY BEFORE WARMER AIR BEGINS
TO MOVE OVER THE SOUTHERN GREAT LAKES. THERE IS GOOD MODEL AGREEMENT
INDICATING 850 MB TEMPERATURE WARMING FROM NEAR -13C AT MID
AFTERNOON TO THE -8C TO -6C RANGE AFTER MIDNIGHT. BOTH THIS AND THE
GENERAL VEERING OF THE LOW LEVEL FLOW WILL KEEP LAKE EFFECT SNOW
SHOWERS OVER SW LOWER AND NORTHERN INDIANA AND PERHAPS JUST BRUSHING
THE NORTHERN THUMB TONIGHT.

LONG TERM...THURSDAY THROUGH TUESDAY

THE ONLY REAL CONCERN ON THURSDAY WILL BE THE LAKE EFFECT SNOW
SHOWERS BRUSHING THE EASTERN THUMB WITH A NORTH NORTHWEST FLOW OFF
LAKE HURON. WHILE THIS TRAJECTORY IS FAVORABLE FOR SNOWFALL OVER
CANADA...THERE APPEARS TO BE ENOUGH OF A FAVORABLE COMPONENT TO THE
WIND DIRECTION TO MAINTAIN THE CHANCY POPS INHERITED BY THE PREVIOUS
FORECAST. WITH THE MOSTLY UNFAVORABLE TRAJECTORY SNOWFALL
AMOUNTS...IF THERE ARE ANY...WILL BE FAIRLY LIGHT WITH A FEW TENTHS
OF AN INCH POSSIBLE.  HIGH PRESSURE THEN BUILDS IN ACROSS THE GREAT
LAKES REGION ON FRIDAY AS THE MOS GUIDANCE SUGGESTS CLEARING SKIES
LATE THURSDAY NIGHT AND INTO FRIDAY. HOWEVER MODEL SOUNDINGS
INDICATE SUBSIDENCE FROM THE HIGH WILL ONCE AGAIN TRAP MOISTURE
BETWEEN 900 AND 950 MB WHICH WILL MEAN LOW STRATUS WILL ONCE AGAIN
PLAGUE THE CENTRAL GREAT LAKES REGION.  THEREFORE BACKED OFF ON THE
CLEARING SKIES DURING THIS PERIOD AND WENT MORE PESSIMISTIC THAN THE
PREVIOUS FORECAST.

THIS HIGH WILL KEEP THE CENTRAL GREAT LAKES DRY DURING THE WEEKEND
AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE SOUTHEASTERN CONUS.
ALTHOUGH THE SUPER BLEND PAINTS CHANCY POPS ACROSS MUCH OF THE
CWA...MAINLY SATURDAY AND SATURDAY NIGHT...THE NWP MODELS KEEP
THINGS DRY WITH THE AFOREMENTIONED DRY HIGH PRESSURE IN PLACE.
GIVEN THE WET BIAS OF THE SUPER BLEND WILL REMOVE POPS DURING THE
WEEKEND AND GO WITH A DRY FORECAST.  NEAR NORMAL TEMPERATURES ARE
EXPECTED DURING THIS TIME WITH HIGHS IN THE LOW TO MID 30S AND LOWS
IN THE MIDDLE TO UPPER 20S.

THE NEXT SYSTEM OF CONSEQUENCE DEVELOPS OVER THE NORTHERN PLAINS ON
MONDAY AND TRACKS OVER THE WESTERN GREAT LAKES ON TUESDAY.  THIS
SYSTEM LOOKS TO HAVE FAIRLY GOOD DYNAMICS WITH A DEEP 500 MB TROUGH
AND A DECENT LOW LEVEL JET.  IT LOOKS LIKE SOUTHEAST MICHIGAN WILL
BE ON THE WARM SIDE OF THIS SYSTEM ON TUESDAY...WITH MAINLY LIQUID
PRECIPITATION EXPECTED AT THIS POINT IN THE FORECAST.

MARINE...

COLD AIR ADVECTION AND STRONG WESTERLY WINDS ARE INCREASING IN THE
WAKE OF A COLD FRONT THAT PASSED THROUGH THE CENTRAL GREAT LAKES
EARLY THIS MORNING. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO
THE STRONGEST FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT
THAT LEVEL. IT SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS
DOWN THOUGH WITH SUSTAINED FLOW PUSHING 20 KNOTS. WILL CONTINUE
SMALL CRAFT ADVISORIES FOR ALL NEARSHORE ZONES FOR THESE ELEVATED
WINDS. WAVES WILL ALSO REACH CRITERIA IN SOME OF THE LAKE HURON
ZONES BUT OFFSHORE FLOW WILL KEEP WAVE HEIGHTS DOWN SOMEWHAT ALONG
WITH SOME ICE COVER SHOWING UP IN INNER SAGINAW BAY. WINDS WILL
DECREASE BELOW CRITERIA THIS AFTERNOON BUT WILL STAY ELEVATED
THROUGH TONIGHT AS THEY VEER TO THE NORTHWEST. ALTHOUGH WINDS WILL
FALL BELOW CRITERIA...THE CONTINUED FETCH OFF LAKE HURON WITH THE
NORTHWEST WINDS WILL MAINTAIN HIGHER WAVES THROUGH TONIGHT ACROSS
OUTER SAGINAW BAY AND LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH.
WINDS AND WAVES WILL CONTINUE TO SLOWLY CALM AS HIGH PRESSURE
BUILDS IN ACROSS THE CENTRAL GREAT LAKES THURSDAY AND FRIDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LHZ422-442-
     443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

AVIATION.....HLO
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 171150
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
650 AM EST WED DEC 17 2014

.AVIATION...

//DISCUSSION...

COLDER AIR IS RUSHING INTO SE MICHIGAN BEHIND THE FRONT THAT HAS
EXITED INTO ONTARIO. THE ALREADY WELL MIXED BOUNDARY LAYER CONSISTS
OF WESTERLY WIND GUSTS AROUND 25 KNOTS...WITH A FEW GUSTS NEAR 30
KNOTS POSSIBLE. THE GUSTY CONDITIONS WILL PERSIST THROUGH THE DAY
BUT THE PEAK GUSTS WILL DIMINISH SLIGHTLY BY MID AFTERNOON. ALONG
WITH THE WIND...MVFR CEILING WITH SOME FLURRIES WILL GRADUALLY MIX
INTO VFR DURING THE AFTERNOON BUT REMAIN BELOW 5000 FEET. THE
SURFACE PRESSURE TROUGH OVER NORTHERN LOWER MICHIGAN DURING THE DAY
WILL SETTLE SOUTHWARD TONIGHT AND WILL LIKELY SUPPORT THE RETURN OF
MVFR CEILING MOST AREAS AFTER MIDNIGHT.

FOR DTW... A SURGE OF COLD AIR MOVING BACK INTO THE REGION WILL
DRIVE WESTERLY WINDS FROM 260-280 WITH GUSTS IN THE 25 TO 30 KNOT
RANGE TODAY...MAINLY DURING THE MORNING. LIGHT SNOW SHOWERS WITHIN
THE SURGE OF COLD AIR DURING THE MORNING ARE NOT EXPECTED TO PRESENT
A RESTRICTION OR RESULT IN ACCUMULATION.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY AND TONIGHT.

* HIGH CONFIDENCE IN WIND GUSTS 25-30 KNOTS FROM 260-280 TODAY.

* HIGH CONFIDENCE IN SNOW AS PRECIPITATION TYPE.

&&

.PREV DISCUSSION...ISSUED 350 AM EST WED DEC 17 2014

SHORT TERM... TODAY AND TONIGHT

AFTER 3 DAYS OF MAX TEMPERATURES IN THE 40S AND LOWER 50S...NORMAL
DECEMBER AIR IS SURGING BACK INTO SE MICHIGAN FOR TODAY. THIS WILL
LIMIT HIGH TEMPERATURES TO THE LOWER AND MID 30S LEADING INTO LOWS
TONIGHT IN THE MID 20S. LIGHT SNOW WILL LINGER NEAR THE TRI CITIES
AND NORTHERN THUMB...MAINLY DURING THE MORNING...WITH LITTLE MORE
THAN A FLURRY OVER THE REST OF SE MICHIGAN.

LIGHT SNOW ONGOING OVER THE SAGINAW VALLEY AND NORTHERN THUMB BEFORE
SUNRISE IS TIED TO AN AXIS OF DEFORMATION IN THE LOW TO MID LEVELS.
THIS FORCING WILL CONTINUE TO SHEAR INTO MORE OF A WEST TO EAST
ORIENTATION DURING THE MORNING WITH THE STRONGEST DYNAMIC FORCING
DISPLACED FROM THE MOISTURE AXIS. THIS WILL MAINTAIN STEADY BUT
LIGHT PRECIPITATION OVER THE NORTHERN GREAT LAKES AND LEAVE THE TRI
CITIES AND NORTHERN THUMB ON THE SOUTHERN FRINGE OF THE PATTERN. AT
THE SAME TIME...DRY AIR WILL CONTINUE TO SLIDE OVER THE REST OF SE
MICHIGAN AS STRONG SUBSIDENCE OCCURS BETWEEN THE DEFORMATION AXIS
ASSOCIATED WITH THE TRAILING UPPER TROUGH AND NORTH FLANK OF THE
UPPER JET AXIS THAT IS CENTERED WELL SOUTH OF THE GREAT LAKES. THIS
WILL ONLY ALLOW WEAK LAKE MICHIGAN ACTIVATION WHICH WILL STRUGGLE TO
MOVE THIS FAR EAST IN ANY FORM GREATER THAN FLURRIES WHILE THE LOW
LEVEL THERMAL TROUGH IS OVERHEAD.

THE UPPER TROUGH WILL SLIDE QUICKLY EASTWARD BY TONIGHT AND LEAVE
TRAILING CYCLONIC OVERHEAD THAT WILL ALLOW A MODEST UPTICK IN
ACTIVITY OFF LAKE MICHIGAN AND HURON EARLY BEFORE WARMER AIR BEGINS
TO MOVE OVER THE SOUTHERN GREAT LAKES. THERE IS GOOD MODEL AGREEMENT
INDICATING 850 MB TEMPERATURE WARMING FROM NEAR -13C AT MID
AFTERNOON TO THE -8C TO -6C RANGE AFTER MIDNIGHT. BOTH THIS AND THE
GENERAL VEERING OF THE LOW LEVEL FLOW WILL KEEP LAKE EFFECT SNOW
SHOWERS OVER SW LOWER AND NORTHERN INDIANA AND PERHAPS JUST BRUSHING
THE NORTHERN THUMB TONIGHT.

LONG TERM...THURSDAY THROUGH TUESDAY

THE ONLY REAL CONCERN ON THURSDAY WILL BE THE LAKE EFFECT SNOW
SHOWERS BRUSHING THE EASTERN THUMB WITH A NORTH NORTHWEST FLOW OFF
LAKE HURON. WHILE THIS TRAJECTORY IS FAVORABLE FOR SNOWFALL OVER
CANADA...THERE APPEARS TO BE ENOUGH OF A FAVORABLE COMPONENT TO THE
WIND DIRECTION TO MAINTAIN THE CHANCY POPS INHERITED BY THE PREVIOUS
FORECAST. WITH THE MOSTLY UNFAVORABLE TRAJECTORY SNOWFALL
AMOUNTS...IF THERE ARE ANY...WILL BE FAIRLY LIGHT WITH A FEW TENTHS
OF AN INCH POSSIBLE.  HIGH PRESSURE THEN BUILDS IN ACROSS THE GREAT
LAKES REGION ON FRIDAY AS THE MOS GUIDANCE SUGGESTS CLEARING SKIES
LATE THURSDAY NIGHT AND INTO FRIDAY. HOWEVER MODEL SOUNDINGS
INDICATE SUBSIDENCE FROM THE HIGH WILL ONCE AGAIN TRAP MOISTURE
BETWEEN 900 AND 950 MB WHICH WILL MEAN LOW STRATUS WILL ONCE AGAIN
PLAGUE THE CENTRAL GREAT LAKES REGION.  THEREFORE BACKED OFF ON THE
CLEARING SKIES DURING THIS PERIOD AND WENT MORE PESSIMISTIC THAN THE
PREVIOUS FORECAST.

THIS HIGH WILL KEEP THE CENTRAL GREAT LAKES DRY DURING THE WEEKEND
AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE SOUTHEASTERN CONUS.
ALTHOUGH THE SUPER BLEND PAINTS CHANCY POPS ACROSS MUCH OF THE
CWA...MAINLY SATURDAY AND SATURDAY NIGHT...THE NWP MODELS KEEP
THINGS DRY WITH THE AFOREMENTIONED DRY HIGH PRESSURE IN PLACE.
GIVEN THE WET BIAS OF THE SUPER BLEND WILL REMOVE POPS DURING THE
WEEKEND AND GO WITH A DRY FORECAST.  NEAR NORMAL TEMPERATURES ARE
EXPECTED DURING THIS TIME WITH HIGHS IN THE LOW TO MID 30S AND LOWS
IN THE MIDDLE TO UPPER 20S.

THE NEXT SYSTEM OF CONSEQUENCE DEVELOPS OVER THE NORTHERN PLAINS ON
MONDAY AND TRACKS OVER THE WESTERN GREAT LAKES ON TUESDAY.  THIS
SYSTEM LOOKS TO HAVE FAIRLY GOOD DYNAMICS WITH A DEEP 500 MB TROUGH
AND A DECENT LOW LEVEL JET.  IT LOOKS LIKE SOUTHEAST MICHIGAN WILL
BE ON THE WARM SIDE OF THIS SYSTEM ON TUESDAY...WITH MAINLY LIQUID
PRECIPITATION EXPECTED AT THIS POINT IN THE FORECAST.

MARINE...

COLD AIR ADVECTION AND STRONG WESTERLY WINDS ARE INCREASING IN THE
WAKE OF A COLD FRONT THAT PASSED THROUGH THE CENTRAL GREAT LAKES
EARLY THIS MORNING. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO
THE STRONGEST FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT
THAT LEVEL. IT SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS
DOWN THOUGH WITH SUSTAINED FLOW PUSHING 20 KNOTS. WILL CONTINUE
SMALL CRAFT ADVISORIES FOR ALL NEARSHORE ZONES FOR THESE ELEVATED
WINDS. WAVES WILL ALSO REACH CRITERIA IN SOME OF THE LAKE HURON
ZONES BUT OFFSHORE FLOW WILL KEEP WAVE HEIGHTS DOWN SOMEWHAT ALONG
WITH SOME ICE COVER SHOWING UP IN INNER SAGINAW BAY. WINDS WILL
DECREASE BELOW CRITERIA THIS AFTERNOON BUT WILL STAY ELEVATED
THROUGH TONIGHT AS THEY VEER TO THE NORTHWEST. ALTHOUGH WINDS WILL
FALL BELOW CRITERIA...THE CONTINUED FETCH OFF LAKE HURON WITH THE
NORTHWEST WINDS WILL MAINTAIN HIGHER WAVES THROUGH TONIGHT ACROSS
OUTER SAGINAW BAY AND LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH.
WINDS AND WAVES WILL CONTINUE TO SLOWLY CALM AS HIGH PRESSURE
BUILDS IN ACROSS THE CENTRAL GREAT LAKES THURSDAY AND FRIDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.

LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
             LHZ422-442- 443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 171150
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
650 AM EST WED DEC 17 2014

.AVIATION...

//DISCUSSION...

COLDER AIR IS RUSHING INTO SE MICHIGAN BEHIND THE FRONT THAT HAS
EXITED INTO ONTARIO. THE ALREADY WELL MIXED BOUNDARY LAYER CONSISTS
OF WESTERLY WIND GUSTS AROUND 25 KNOTS...WITH A FEW GUSTS NEAR 30
KNOTS POSSIBLE. THE GUSTY CONDITIONS WILL PERSIST THROUGH THE DAY
BUT THE PEAK GUSTS WILL DIMINISH SLIGHTLY BY MID AFTERNOON. ALONG
WITH THE WIND...MVFR CEILING WITH SOME FLURRIES WILL GRADUALLY MIX
INTO VFR DURING THE AFTERNOON BUT REMAIN BELOW 5000 FEET. THE
SURFACE PRESSURE TROUGH OVER NORTHERN LOWER MICHIGAN DURING THE DAY
WILL SETTLE SOUTHWARD TONIGHT AND WILL LIKELY SUPPORT THE RETURN OF
MVFR CEILING MOST AREAS AFTER MIDNIGHT.

FOR DTW... A SURGE OF COLD AIR MOVING BACK INTO THE REGION WILL
DRIVE WESTERLY WINDS FROM 260-280 WITH GUSTS IN THE 25 TO 30 KNOT
RANGE TODAY...MAINLY DURING THE MORNING. LIGHT SNOW SHOWERS WITHIN
THE SURGE OF COLD AIR DURING THE MORNING ARE NOT EXPECTED TO PRESENT
A RESTRICTION OR RESULT IN ACCUMULATION.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY AND TONIGHT.

* HIGH CONFIDENCE IN WIND GUSTS 25-30 KNOTS FROM 260-280 TODAY.

* HIGH CONFIDENCE IN SNOW AS PRECIPITATION TYPE.

&&

.PREV DISCUSSION...ISSUED 350 AM EST WED DEC 17 2014

SHORT TERM... TODAY AND TONIGHT

AFTER 3 DAYS OF MAX TEMPERATURES IN THE 40S AND LOWER 50S...NORMAL
DECEMBER AIR IS SURGING BACK INTO SE MICHIGAN FOR TODAY. THIS WILL
LIMIT HIGH TEMPERATURES TO THE LOWER AND MID 30S LEADING INTO LOWS
TONIGHT IN THE MID 20S. LIGHT SNOW WILL LINGER NEAR THE TRI CITIES
AND NORTHERN THUMB...MAINLY DURING THE MORNING...WITH LITTLE MORE
THAN A FLURRY OVER THE REST OF SE MICHIGAN.

LIGHT SNOW ONGOING OVER THE SAGINAW VALLEY AND NORTHERN THUMB BEFORE
SUNRISE IS TIED TO AN AXIS OF DEFORMATION IN THE LOW TO MID LEVELS.
THIS FORCING WILL CONTINUE TO SHEAR INTO MORE OF A WEST TO EAST
ORIENTATION DURING THE MORNING WITH THE STRONGEST DYNAMIC FORCING
DISPLACED FROM THE MOISTURE AXIS. THIS WILL MAINTAIN STEADY BUT
LIGHT PRECIPITATION OVER THE NORTHERN GREAT LAKES AND LEAVE THE TRI
CITIES AND NORTHERN THUMB ON THE SOUTHERN FRINGE OF THE PATTERN. AT
THE SAME TIME...DRY AIR WILL CONTINUE TO SLIDE OVER THE REST OF SE
MICHIGAN AS STRONG SUBSIDENCE OCCURS BETWEEN THE DEFORMATION AXIS
ASSOCIATED WITH THE TRAILING UPPER TROUGH AND NORTH FLANK OF THE
UPPER JET AXIS THAT IS CENTERED WELL SOUTH OF THE GREAT LAKES. THIS
WILL ONLY ALLOW WEAK LAKE MICHIGAN ACTIVATION WHICH WILL STRUGGLE TO
MOVE THIS FAR EAST IN ANY FORM GREATER THAN FLURRIES WHILE THE LOW
LEVEL THERMAL TROUGH IS OVERHEAD.

THE UPPER TROUGH WILL SLIDE QUICKLY EASTWARD BY TONIGHT AND LEAVE
TRAILING CYCLONIC OVERHEAD THAT WILL ALLOW A MODEST UPTICK IN
ACTIVITY OFF LAKE MICHIGAN AND HURON EARLY BEFORE WARMER AIR BEGINS
TO MOVE OVER THE SOUTHERN GREAT LAKES. THERE IS GOOD MODEL AGREEMENT
INDICATING 850 MB TEMPERATURE WARMING FROM NEAR -13C AT MID
AFTERNOON TO THE -8C TO -6C RANGE AFTER MIDNIGHT. BOTH THIS AND THE
GENERAL VEERING OF THE LOW LEVEL FLOW WILL KEEP LAKE EFFECT SNOW
SHOWERS OVER SW LOWER AND NORTHERN INDIANA AND PERHAPS JUST BRUSHING
THE NORTHERN THUMB TONIGHT.

LONG TERM...THURSDAY THROUGH TUESDAY

THE ONLY REAL CONCERN ON THURSDAY WILL BE THE LAKE EFFECT SNOW
SHOWERS BRUSHING THE EASTERN THUMB WITH A NORTH NORTHWEST FLOW OFF
LAKE HURON. WHILE THIS TRAJECTORY IS FAVORABLE FOR SNOWFALL OVER
CANADA...THERE APPEARS TO BE ENOUGH OF A FAVORABLE COMPONENT TO THE
WIND DIRECTION TO MAINTAIN THE CHANCY POPS INHERITED BY THE PREVIOUS
FORECAST. WITH THE MOSTLY UNFAVORABLE TRAJECTORY SNOWFALL
AMOUNTS...IF THERE ARE ANY...WILL BE FAIRLY LIGHT WITH A FEW TENTHS
OF AN INCH POSSIBLE.  HIGH PRESSURE THEN BUILDS IN ACROSS THE GREAT
LAKES REGION ON FRIDAY AS THE MOS GUIDANCE SUGGESTS CLEARING SKIES
LATE THURSDAY NIGHT AND INTO FRIDAY. HOWEVER MODEL SOUNDINGS
INDICATE SUBSIDENCE FROM THE HIGH WILL ONCE AGAIN TRAP MOISTURE
BETWEEN 900 AND 950 MB WHICH WILL MEAN LOW STRATUS WILL ONCE AGAIN
PLAGUE THE CENTRAL GREAT LAKES REGION.  THEREFORE BACKED OFF ON THE
CLEARING SKIES DURING THIS PERIOD AND WENT MORE PESSIMISTIC THAN THE
PREVIOUS FORECAST.

THIS HIGH WILL KEEP THE CENTRAL GREAT LAKES DRY DURING THE WEEKEND
AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE SOUTHEASTERN CONUS.
ALTHOUGH THE SUPER BLEND PAINTS CHANCY POPS ACROSS MUCH OF THE
CWA...MAINLY SATURDAY AND SATURDAY NIGHT...THE NWP MODELS KEEP
THINGS DRY WITH THE AFOREMENTIONED DRY HIGH PRESSURE IN PLACE.
GIVEN THE WET BIAS OF THE SUPER BLEND WILL REMOVE POPS DURING THE
WEEKEND AND GO WITH A DRY FORECAST.  NEAR NORMAL TEMPERATURES ARE
EXPECTED DURING THIS TIME WITH HIGHS IN THE LOW TO MID 30S AND LOWS
IN THE MIDDLE TO UPPER 20S.

THE NEXT SYSTEM OF CONSEQUENCE DEVELOPS OVER THE NORTHERN PLAINS ON
MONDAY AND TRACKS OVER THE WESTERN GREAT LAKES ON TUESDAY.  THIS
SYSTEM LOOKS TO HAVE FAIRLY GOOD DYNAMICS WITH A DEEP 500 MB TROUGH
AND A DECENT LOW LEVEL JET.  IT LOOKS LIKE SOUTHEAST MICHIGAN WILL
BE ON THE WARM SIDE OF THIS SYSTEM ON TUESDAY...WITH MAINLY LIQUID
PRECIPITATION EXPECTED AT THIS POINT IN THE FORECAST.

MARINE...

COLD AIR ADVECTION AND STRONG WESTERLY WINDS ARE INCREASING IN THE
WAKE OF A COLD FRONT THAT PASSED THROUGH THE CENTRAL GREAT LAKES
EARLY THIS MORNING. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO
THE STRONGEST FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT
THAT LEVEL. IT SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS
DOWN THOUGH WITH SUSTAINED FLOW PUSHING 20 KNOTS. WILL CONTINUE
SMALL CRAFT ADVISORIES FOR ALL NEARSHORE ZONES FOR THESE ELEVATED
WINDS. WAVES WILL ALSO REACH CRITERIA IN SOME OF THE LAKE HURON
ZONES BUT OFFSHORE FLOW WILL KEEP WAVE HEIGHTS DOWN SOMEWHAT ALONG
WITH SOME ICE COVER SHOWING UP IN INNER SAGINAW BAY. WINDS WILL
DECREASE BELOW CRITERIA THIS AFTERNOON BUT WILL STAY ELEVATED
THROUGH TONIGHT AS THEY VEER TO THE NORTHWEST. ALTHOUGH WINDS WILL
FALL BELOW CRITERIA...THE CONTINUED FETCH OFF LAKE HURON WITH THE
NORTHWEST WINDS WILL MAINTAIN HIGHER WAVES THROUGH TONIGHT ACROSS
OUTER SAGINAW BAY AND LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH.
WINDS AND WAVES WILL CONTINUE TO SLOWLY CALM AS HIGH PRESSURE
BUILDS IN ACROSS THE CENTRAL GREAT LAKES THURSDAY AND FRIDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.

LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
             LHZ422-442- 443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 170850
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
350 AM EST WED DEC 17 2014

.SHORT TERM... TODAY AND TONIGHT

AFTER 3 DAYS OF MAX TEMPERATURES IN THE 40S AND LOWER 50S...NORMAL
DECEMBER AIR IS SURGING BACK INTO SE MICHIGAN FOR TODAY. THIS WILL
LIMIT HIGH TEMPERATURES TO THE LOWER AND MID 30S LEADING INTO LOWS
TONIGHT IN THE MID 20S. LIGHT SNOW WILL LINGER NEAR THE TRI CITIES
AND NORTHERN THUMB...MAINLY DURING THE MORNING...WITH LITTLE MORE
THAN A FLURRY OVER THE REST OF SE MICHIGAN.

LIGHT SNOW ONGOING OVER THE SAGINAW VALLEY AND NORTHERN THUMB BEFORE
SUNRISE IS TIED TO AN AXIS OF DEFORMATION IN THE LOW TO MID LEVELS.
THIS FORCING WILL CONTINUE TO SHEAR INTO MORE OF A WEST TO EAST
ORIENTATION DURING THE MORNING WITH THE STRONGEST DYNAMIC FORCING
DISPLACED FROM THE MOISTURE AXIS. THIS WILL MAINTAIN STEADY BUT
LIGHT PRECIPITATION OVER THE NORTHERN GREAT LAKES AND LEAVE THE TRI
CITIES AND NORTHERN THUMB ON THE SOUTHERN FRINGE OF THE PATTERN. AT
THE SAME TIME...DRY AIR WILL CONTINUE TO SLIDE OVER THE REST OF SE
MICHIGAN AS STRONG SUBSIDENCE OCCURS BETWEEN THE DEFORMATION AXIS
ASSOCIATED WITH THE TRAILING UPPER TROUGH AND NORTH FLANK OF THE
UPPER JET AXIS THAT IS CENTERED WELL SOUTH OF THE GREAT LAKES. THIS
WILL ONLY ALLOW WEAK LAKE MICHIGAN ACTIVATION WHICH WILL STRUGGLE TO
MOVE THIS FAR EAST IN ANY FORM GREATER THAN FLURRIES WHILE THE LOW
LEVEL THERMAL TROUGH IS OVERHEAD.

THE UPPER TROUGH WILL SLIDE QUICKLY EASTWARD BY TONIGHT AND LEAVE
TRAILING CYCLONIC OVERHEAD THAT WILL ALLOW A MODEST UPTICK IN
ACTIVITY OFF LAKE MICHIGAN AND HURON EARLY BEFORE WARMER AIR BEGINS
TO MOVE OVER THE SOUTHERN GREAT LAKES. THERE IS GOOD MODEL AGREEMENT
INDICATING 850 MB TEMPERATURE WARMING FROM NEAR -13C AT MID
AFTERNOON TO THE -8C TO -6C RANGE AFTER MIDNIGHT. BOTH THIS AND THE
GENERAL VEERING OF THE LOW LEVEL FLOW WILL KEEP LAKE EFFECT SNOW
SHOWERS OVER SW LOWER AND NORTHERN INDIANA AND PERHAPS JUST BRUSHING
THE NORTHERN THUMB TONIGHT.

&&

.LONG TERM...THURSDAY THROUGH TUESDAY

THE ONLY REAL CONCERN ON THURSDAY WILL BE THE LAKE EFFECT SNOW
SHOWERS BRUSHING THE EASTERN THUMB WITH A NORTH NORTHWEST FLOW OFF
LAKE HURON. WHILE THIS TRAJECTORY IS FAVORABLE FOR SNOWFALL OVER
CANADA...THERE APPEARS TO BE ENOUGH OF A FAVORABLE COMPONENT TO THE
WIND DIRECTION TO MAINTAIN THE CHANCY POPS INHERITED BY THE PREVIOUS
FORECAST. WITH THE MOSTLY UNFAVORABLE TRAJECTORY SNOWFALL
AMOUNTS...IF THERE ARE ANY...WILL BE FAIRLY LIGHT WITH A FEW TENTHS
OF AN INCH POSSIBLE.  HIGH PRESSURE THEN BUILDS IN ACROSS THE GREAT
LAKES REGION ON FRIDAY AS THE MOS GUIDANCE SUGGESTS CLEARING SKIES
LATE THURSDAY NIGHT AND INTO FRIDAY. HOWEVER MODEL SOUNDINGS
INDICATE SUBSIDENCE FROM THE HIGH WILL ONCE AGAIN TRAP MOISTURE
BETWEEN 900 AND 950 MB WHICH WILL MEAN LOW STRATUS WILL ONCE AGAIN
PLAGUE THE CENTRAL GREAT LAKES REGION.  THEREFORE BACKED OFF ON THE
CLEARING SKIES DURING THIS PERIOD AND WENT MORE PESSIMISTIC THAN THE
PREVIOUS FORECAST.

THIS HIGH WILL KEEP THE CENTRAL GREAT LAKES DRY DURING THE WEEKEND
AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE SOUTHEASTERN CONUS.
ALTHOUGH THE SUPER BLEND PAINTS CHANCY POPS ACROSS MUCH OF THE
CWA...MAINLY SATURDAY AND SATURDAY NIGHT...THE NWP MODELS KEEP
THINGS DRY WITH THE AFOREMENTIONED DRY HIGH PRESSURE IN PLACE.
GIVEN THE WET BIAS OF THE SUPER BLEND WILL REMOVE POPS DURING THE
WEEKEND AND GO WITH A DRY FORECAST.  NEAR NORMAL TEMPERATURES ARE
EXPECTED DURING THIS TIME WITH HIGHS IN THE LOW TO MID 30S AND LOWS
IN THE MIDDLE TO UPPER 20S.

THE NEXT SYSTEM OF CONSEQUENCE DEVELOPS OVER THE NORTHERN PLAINS ON
MONDAY AND TRACKS OVER THE WESTERN GREAT LAKES ON TUESDAY.  THIS
SYSTEM LOOKS TO HAVE FAIRLY GOOD DYNAMICS WITH A DEEP 500 MB TROUGH
AND A DECENT LOW LEVEL JET.  IT LOOKS LIKE SOUTHEAST MICHIGAN WILL
BE ON THE WARM SIDE OF THIS SYSTEM ON TUESDAY...WITH MAINLY LIQUID
PRECIPITATION EXPECTED AT THIS POINT IN THE FORECAST.

&&

.MARINE...

COLD AIR ADVECTION AND STRONG WESTERLY WINDS ARE INCREASING IN THE
WAKE OF A COLD FRONT THAT PASSED THROUGH THE CENTRAL GREAT LAKES
EARLY THIS MORNING. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO
THE STRONGEST FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT
THAT LEVEL. IT SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS
DOWN THOUGH WITH SUSTAINED FLOW PUSHING 20 KNOTS. WILL CONTINUE
SMALL CRAFT ADVISORIES FOR ALL NEARSHORE ZONES FOR THESE ELEVATED
WINDS. WAVES WILL ALSO REACH CRITERIA IN SOME OF THE LAKE HURON
ZONES BUT OFFSHORE FLOW WILL KEEP WAVE HEIGHTS DOWN SOMEWHAT ALONG
WITH SOME ICE COVER SHOWING UP IN INNER SAGINAW BAY. WINDS WILL
DECREASE BELOW CRITERIA THIS AFTERNOON BUT WILL STAY ELEVATED
THROUGH TONIGHT AS THEY VEER TO THE NORTHWEST. ALTHOUGH WINDS WILL
FALL BELOW CRITERIA...THE CONTINUED FETCH OFF LAKE HURON WITH THE
NORTHWEST WINDS WILL MAINTAIN HIGHER WAVES THROUGH TONIGHT ACROSS
OUTER SAGINAW BAY AND LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH.
WINDS AND WAVES WILL CONTINUE TO SLOWLY CALM AS HIGH PRESSURE
BUILDS IN ACROSS THE CENTRAL GREAT LAKES THURSDAY AND FRIDAY.

&&

.AVIATION...ISSUED 1154 PM EST TUE DEC 16 2014

//DISCUSSION...

COLD FRONT WILL CONTINUE THROUGH SOUTHEAST MICHIGAN EARLY THIS
MORNING.  A GUSTY POST-COLD FRONTAL WESTERLY WIND WILL EMERGE DURING
THIS TIME...PEAK GUSTS CLIMBING INTO THE 25 KNOT RANGE THROUGHOUT
THE MORNING PERIOD.  THE ENSUING COLD AIR ADVECTION WILL ALLOW ANY
LAGGING IFR CEILING HEIGHTS TO LIFT INTO MVFR.  RECENT RADAR TRENDS
SUGGEST A PERIOD OF LIGHT SNOW WILL BE POSSIBLE AS THE BACK EDGE OF
THE DEEPER MOISTURE LIFTS THROUGH...GREATEST POTENTIAL AT MBS/FNT.
EXTENSIVE STRATUS DECK WILL TRANSITION TOWARD A HIGH MVFR/LOW VFR
CEILING ON WEDNESDAY.

FOR DTW...TURNING GUSTY OUT OF THE WEST EARLY THIS MORNING AS COLDER
AIR FUNNELS IN.  GUSTS INTO THE 25 KNOT RANGE THROUGHOUT THE MORNING
PERIOD.  POTENTIAL FOR A FEW BRIEF LIGHT SNOW SHOWERS OR FLURRIES
PRIOR TO 12Z WILL BE LIMITED AS THE DEEPER MOISTURE EXITS BEFORE THE
AIR BECOMES COLD ENOUGH.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.

LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     LHZ422-442- 443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 170850
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
350 AM EST WED DEC 17 2014

.SHORT TERM... TODAY AND TONIGHT

AFTER 3 DAYS OF MAX TEMPERATURES IN THE 40S AND LOWER 50S...NORMAL
DECEMBER AIR IS SURGING BACK INTO SE MICHIGAN FOR TODAY. THIS WILL
LIMIT HIGH TEMPERATURES TO THE LOWER AND MID 30S LEADING INTO LOWS
TONIGHT IN THE MID 20S. LIGHT SNOW WILL LINGER NEAR THE TRI CITIES
AND NORTHERN THUMB...MAINLY DURING THE MORNING...WITH LITTLE MORE
THAN A FLURRY OVER THE REST OF SE MICHIGAN.

LIGHT SNOW ONGOING OVER THE SAGINAW VALLEY AND NORTHERN THUMB BEFORE
SUNRISE IS TIED TO AN AXIS OF DEFORMATION IN THE LOW TO MID LEVELS.
THIS FORCING WILL CONTINUE TO SHEAR INTO MORE OF A WEST TO EAST
ORIENTATION DURING THE MORNING WITH THE STRONGEST DYNAMIC FORCING
DISPLACED FROM THE MOISTURE AXIS. THIS WILL MAINTAIN STEADY BUT
LIGHT PRECIPITATION OVER THE NORTHERN GREAT LAKES AND LEAVE THE TRI
CITIES AND NORTHERN THUMB ON THE SOUTHERN FRINGE OF THE PATTERN. AT
THE SAME TIME...DRY AIR WILL CONTINUE TO SLIDE OVER THE REST OF SE
MICHIGAN AS STRONG SUBSIDENCE OCCURS BETWEEN THE DEFORMATION AXIS
ASSOCIATED WITH THE TRAILING UPPER TROUGH AND NORTH FLANK OF THE
UPPER JET AXIS THAT IS CENTERED WELL SOUTH OF THE GREAT LAKES. THIS
WILL ONLY ALLOW WEAK LAKE MICHIGAN ACTIVATION WHICH WILL STRUGGLE TO
MOVE THIS FAR EAST IN ANY FORM GREATER THAN FLURRIES WHILE THE LOW
LEVEL THERMAL TROUGH IS OVERHEAD.

THE UPPER TROUGH WILL SLIDE QUICKLY EASTWARD BY TONIGHT AND LEAVE
TRAILING CYCLONIC OVERHEAD THAT WILL ALLOW A MODEST UPTICK IN
ACTIVITY OFF LAKE MICHIGAN AND HURON EARLY BEFORE WARMER AIR BEGINS
TO MOVE OVER THE SOUTHERN GREAT LAKES. THERE IS GOOD MODEL AGREEMENT
INDICATING 850 MB TEMPERATURE WARMING FROM NEAR -13C AT MID
AFTERNOON TO THE -8C TO -6C RANGE AFTER MIDNIGHT. BOTH THIS AND THE
GENERAL VEERING OF THE LOW LEVEL FLOW WILL KEEP LAKE EFFECT SNOW
SHOWERS OVER SW LOWER AND NORTHERN INDIANA AND PERHAPS JUST BRUSHING
THE NORTHERN THUMB TONIGHT.

&&

.LONG TERM...THURSDAY THROUGH TUESDAY

THE ONLY REAL CONCERN ON THURSDAY WILL BE THE LAKE EFFECT SNOW
SHOWERS BRUSHING THE EASTERN THUMB WITH A NORTH NORTHWEST FLOW OFF
LAKE HURON. WHILE THIS TRAJECTORY IS FAVORABLE FOR SNOWFALL OVER
CANADA...THERE APPEARS TO BE ENOUGH OF A FAVORABLE COMPONENT TO THE
WIND DIRECTION TO MAINTAIN THE CHANCY POPS INHERITED BY THE PREVIOUS
FORECAST. WITH THE MOSTLY UNFAVORABLE TRAJECTORY SNOWFALL
AMOUNTS...IF THERE ARE ANY...WILL BE FAIRLY LIGHT WITH A FEW TENTHS
OF AN INCH POSSIBLE.  HIGH PRESSURE THEN BUILDS IN ACROSS THE GREAT
LAKES REGION ON FRIDAY AS THE MOS GUIDANCE SUGGESTS CLEARING SKIES
LATE THURSDAY NIGHT AND INTO FRIDAY. HOWEVER MODEL SOUNDINGS
INDICATE SUBSIDENCE FROM THE HIGH WILL ONCE AGAIN TRAP MOISTURE
BETWEEN 900 AND 950 MB WHICH WILL MEAN LOW STRATUS WILL ONCE AGAIN
PLAGUE THE CENTRAL GREAT LAKES REGION.  THEREFORE BACKED OFF ON THE
CLEARING SKIES DURING THIS PERIOD AND WENT MORE PESSIMISTIC THAN THE
PREVIOUS FORECAST.

THIS HIGH WILL KEEP THE CENTRAL GREAT LAKES DRY DURING THE WEEKEND
AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE SOUTHEASTERN CONUS.
ALTHOUGH THE SUPER BLEND PAINTS CHANCY POPS ACROSS MUCH OF THE
CWA...MAINLY SATURDAY AND SATURDAY NIGHT...THE NWP MODELS KEEP
THINGS DRY WITH THE AFOREMENTIONED DRY HIGH PRESSURE IN PLACE.
GIVEN THE WET BIAS OF THE SUPER BLEND WILL REMOVE POPS DURING THE
WEEKEND AND GO WITH A DRY FORECAST.  NEAR NORMAL TEMPERATURES ARE
EXPECTED DURING THIS TIME WITH HIGHS IN THE LOW TO MID 30S AND LOWS
IN THE MIDDLE TO UPPER 20S.

THE NEXT SYSTEM OF CONSEQUENCE DEVELOPS OVER THE NORTHERN PLAINS ON
MONDAY AND TRACKS OVER THE WESTERN GREAT LAKES ON TUESDAY.  THIS
SYSTEM LOOKS TO HAVE FAIRLY GOOD DYNAMICS WITH A DEEP 500 MB TROUGH
AND A DECENT LOW LEVEL JET.  IT LOOKS LIKE SOUTHEAST MICHIGAN WILL
BE ON THE WARM SIDE OF THIS SYSTEM ON TUESDAY...WITH MAINLY LIQUID
PRECIPITATION EXPECTED AT THIS POINT IN THE FORECAST.

&&

.MARINE...

COLD AIR ADVECTION AND STRONG WESTERLY WINDS ARE INCREASING IN THE
WAKE OF A COLD FRONT THAT PASSED THROUGH THE CENTRAL GREAT LAKES
EARLY THIS MORNING. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO
THE STRONGEST FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT
THAT LEVEL. IT SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS
DOWN THOUGH WITH SUSTAINED FLOW PUSHING 20 KNOTS. WILL CONTINUE
SMALL CRAFT ADVISORIES FOR ALL NEARSHORE ZONES FOR THESE ELEVATED
WINDS. WAVES WILL ALSO REACH CRITERIA IN SOME OF THE LAKE HURON
ZONES BUT OFFSHORE FLOW WILL KEEP WAVE HEIGHTS DOWN SOMEWHAT ALONG
WITH SOME ICE COVER SHOWING UP IN INNER SAGINAW BAY. WINDS WILL
DECREASE BELOW CRITERIA THIS AFTERNOON BUT WILL STAY ELEVATED
THROUGH TONIGHT AS THEY VEER TO THE NORTHWEST. ALTHOUGH WINDS WILL
FALL BELOW CRITERIA...THE CONTINUED FETCH OFF LAKE HURON WITH THE
NORTHWEST WINDS WILL MAINTAIN HIGHER WAVES THROUGH TONIGHT ACROSS
OUTER SAGINAW BAY AND LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH.
WINDS AND WAVES WILL CONTINUE TO SLOWLY CALM AS HIGH PRESSURE
BUILDS IN ACROSS THE CENTRAL GREAT LAKES THURSDAY AND FRIDAY.

&&

.AVIATION...ISSUED 1154 PM EST TUE DEC 16 2014

//DISCUSSION...

COLD FRONT WILL CONTINUE THROUGH SOUTHEAST MICHIGAN EARLY THIS
MORNING.  A GUSTY POST-COLD FRONTAL WESTERLY WIND WILL EMERGE DURING
THIS TIME...PEAK GUSTS CLIMBING INTO THE 25 KNOT RANGE THROUGHOUT
THE MORNING PERIOD.  THE ENSUING COLD AIR ADVECTION WILL ALLOW ANY
LAGGING IFR CEILING HEIGHTS TO LIFT INTO MVFR.  RECENT RADAR TRENDS
SUGGEST A PERIOD OF LIGHT SNOW WILL BE POSSIBLE AS THE BACK EDGE OF
THE DEEPER MOISTURE LIFTS THROUGH...GREATEST POTENTIAL AT MBS/FNT.
EXTENSIVE STRATUS DECK WILL TRANSITION TOWARD A HIGH MVFR/LOW VFR
CEILING ON WEDNESDAY.

FOR DTW...TURNING GUSTY OUT OF THE WEST EARLY THIS MORNING AS COLDER
AIR FUNNELS IN.  GUSTS INTO THE 25 KNOT RANGE THROUGHOUT THE MORNING
PERIOD.  POTENTIAL FOR A FEW BRIEF LIGHT SNOW SHOWERS OR FLURRIES
PRIOR TO 12Z WILL BE LIMITED AS THE DEEPER MOISTURE EXITS BEFORE THE
AIR BECOMES COLD ENOUGH.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.

LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     LHZ422-442- 443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 170850
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
350 AM EST WED DEC 17 2014

.SHORT TERM... TODAY AND TONIGHT

AFTER 3 DAYS OF MAX TEMPERATURES IN THE 40S AND LOWER 50S...NORMAL
DECEMBER AIR IS SURGING BACK INTO SE MICHIGAN FOR TODAY. THIS WILL
LIMIT HIGH TEMPERATURES TO THE LOWER AND MID 30S LEADING INTO LOWS
TONIGHT IN THE MID 20S. LIGHT SNOW WILL LINGER NEAR THE TRI CITIES
AND NORTHERN THUMB...MAINLY DURING THE MORNING...WITH LITTLE MORE
THAN A FLURRY OVER THE REST OF SE MICHIGAN.

LIGHT SNOW ONGOING OVER THE SAGINAW VALLEY AND NORTHERN THUMB BEFORE
SUNRISE IS TIED TO AN AXIS OF DEFORMATION IN THE LOW TO MID LEVELS.
THIS FORCING WILL CONTINUE TO SHEAR INTO MORE OF A WEST TO EAST
ORIENTATION DURING THE MORNING WITH THE STRONGEST DYNAMIC FORCING
DISPLACED FROM THE MOISTURE AXIS. THIS WILL MAINTAIN STEADY BUT
LIGHT PRECIPITATION OVER THE NORTHERN GREAT LAKES AND LEAVE THE TRI
CITIES AND NORTHERN THUMB ON THE SOUTHERN FRINGE OF THE PATTERN. AT
THE SAME TIME...DRY AIR WILL CONTINUE TO SLIDE OVER THE REST OF SE
MICHIGAN AS STRONG SUBSIDENCE OCCURS BETWEEN THE DEFORMATION AXIS
ASSOCIATED WITH THE TRAILING UPPER TROUGH AND NORTH FLANK OF THE
UPPER JET AXIS THAT IS CENTERED WELL SOUTH OF THE GREAT LAKES. THIS
WILL ONLY ALLOW WEAK LAKE MICHIGAN ACTIVATION WHICH WILL STRUGGLE TO
MOVE THIS FAR EAST IN ANY FORM GREATER THAN FLURRIES WHILE THE LOW
LEVEL THERMAL TROUGH IS OVERHEAD.

THE UPPER TROUGH WILL SLIDE QUICKLY EASTWARD BY TONIGHT AND LEAVE
TRAILING CYCLONIC OVERHEAD THAT WILL ALLOW A MODEST UPTICK IN
ACTIVITY OFF LAKE MICHIGAN AND HURON EARLY BEFORE WARMER AIR BEGINS
TO MOVE OVER THE SOUTHERN GREAT LAKES. THERE IS GOOD MODEL AGREEMENT
INDICATING 850 MB TEMPERATURE WARMING FROM NEAR -13C AT MID
AFTERNOON TO THE -8C TO -6C RANGE AFTER MIDNIGHT. BOTH THIS AND THE
GENERAL VEERING OF THE LOW LEVEL FLOW WILL KEEP LAKE EFFECT SNOW
SHOWERS OVER SW LOWER AND NORTHERN INDIANA AND PERHAPS JUST BRUSHING
THE NORTHERN THUMB TONIGHT.

&&

.LONG TERM...THURSDAY THROUGH TUESDAY

THE ONLY REAL CONCERN ON THURSDAY WILL BE THE LAKE EFFECT SNOW
SHOWERS BRUSHING THE EASTERN THUMB WITH A NORTH NORTHWEST FLOW OFF
LAKE HURON. WHILE THIS TRAJECTORY IS FAVORABLE FOR SNOWFALL OVER
CANADA...THERE APPEARS TO BE ENOUGH OF A FAVORABLE COMPONENT TO THE
WIND DIRECTION TO MAINTAIN THE CHANCY POPS INHERITED BY THE PREVIOUS
FORECAST. WITH THE MOSTLY UNFAVORABLE TRAJECTORY SNOWFALL
AMOUNTS...IF THERE ARE ANY...WILL BE FAIRLY LIGHT WITH A FEW TENTHS
OF AN INCH POSSIBLE.  HIGH PRESSURE THEN BUILDS IN ACROSS THE GREAT
LAKES REGION ON FRIDAY AS THE MOS GUIDANCE SUGGESTS CLEARING SKIES
LATE THURSDAY NIGHT AND INTO FRIDAY. HOWEVER MODEL SOUNDINGS
INDICATE SUBSIDENCE FROM THE HIGH WILL ONCE AGAIN TRAP MOISTURE
BETWEEN 900 AND 950 MB WHICH WILL MEAN LOW STRATUS WILL ONCE AGAIN
PLAGUE THE CENTRAL GREAT LAKES REGION.  THEREFORE BACKED OFF ON THE
CLEARING SKIES DURING THIS PERIOD AND WENT MORE PESSIMISTIC THAN THE
PREVIOUS FORECAST.

THIS HIGH WILL KEEP THE CENTRAL GREAT LAKES DRY DURING THE WEEKEND
AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE SOUTHEASTERN CONUS.
ALTHOUGH THE SUPER BLEND PAINTS CHANCY POPS ACROSS MUCH OF THE
CWA...MAINLY SATURDAY AND SATURDAY NIGHT...THE NWP MODELS KEEP
THINGS DRY WITH THE AFOREMENTIONED DRY HIGH PRESSURE IN PLACE.
GIVEN THE WET BIAS OF THE SUPER BLEND WILL REMOVE POPS DURING THE
WEEKEND AND GO WITH A DRY FORECAST.  NEAR NORMAL TEMPERATURES ARE
EXPECTED DURING THIS TIME WITH HIGHS IN THE LOW TO MID 30S AND LOWS
IN THE MIDDLE TO UPPER 20S.

THE NEXT SYSTEM OF CONSEQUENCE DEVELOPS OVER THE NORTHERN PLAINS ON
MONDAY AND TRACKS OVER THE WESTERN GREAT LAKES ON TUESDAY.  THIS
SYSTEM LOOKS TO HAVE FAIRLY GOOD DYNAMICS WITH A DEEP 500 MB TROUGH
AND A DECENT LOW LEVEL JET.  IT LOOKS LIKE SOUTHEAST MICHIGAN WILL
BE ON THE WARM SIDE OF THIS SYSTEM ON TUESDAY...WITH MAINLY LIQUID
PRECIPITATION EXPECTED AT THIS POINT IN THE FORECAST.

&&

.MARINE...

COLD AIR ADVECTION AND STRONG WESTERLY WINDS ARE INCREASING IN THE
WAKE OF A COLD FRONT THAT PASSED THROUGH THE CENTRAL GREAT LAKES
EARLY THIS MORNING. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO
THE STRONGEST FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT
THAT LEVEL. IT SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS
DOWN THOUGH WITH SUSTAINED FLOW PUSHING 20 KNOTS. WILL CONTINUE
SMALL CRAFT ADVISORIES FOR ALL NEARSHORE ZONES FOR THESE ELEVATED
WINDS. WAVES WILL ALSO REACH CRITERIA IN SOME OF THE LAKE HURON
ZONES BUT OFFSHORE FLOW WILL KEEP WAVE HEIGHTS DOWN SOMEWHAT ALONG
WITH SOME ICE COVER SHOWING UP IN INNER SAGINAW BAY. WINDS WILL
DECREASE BELOW CRITERIA THIS AFTERNOON BUT WILL STAY ELEVATED
THROUGH TONIGHT AS THEY VEER TO THE NORTHWEST. ALTHOUGH WINDS WILL
FALL BELOW CRITERIA...THE CONTINUED FETCH OFF LAKE HURON WITH THE
NORTHWEST WINDS WILL MAINTAIN HIGHER WAVES THROUGH TONIGHT ACROSS
OUTER SAGINAW BAY AND LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH.
WINDS AND WAVES WILL CONTINUE TO SLOWLY CALM AS HIGH PRESSURE
BUILDS IN ACROSS THE CENTRAL GREAT LAKES THURSDAY AND FRIDAY.

&&

.AVIATION...ISSUED 1154 PM EST TUE DEC 16 2014

//DISCUSSION...

COLD FRONT WILL CONTINUE THROUGH SOUTHEAST MICHIGAN EARLY THIS
MORNING.  A GUSTY POST-COLD FRONTAL WESTERLY WIND WILL EMERGE DURING
THIS TIME...PEAK GUSTS CLIMBING INTO THE 25 KNOT RANGE THROUGHOUT
THE MORNING PERIOD.  THE ENSUING COLD AIR ADVECTION WILL ALLOW ANY
LAGGING IFR CEILING HEIGHTS TO LIFT INTO MVFR.  RECENT RADAR TRENDS
SUGGEST A PERIOD OF LIGHT SNOW WILL BE POSSIBLE AS THE BACK EDGE OF
THE DEEPER MOISTURE LIFTS THROUGH...GREATEST POTENTIAL AT MBS/FNT.
EXTENSIVE STRATUS DECK WILL TRANSITION TOWARD A HIGH MVFR/LOW VFR
CEILING ON WEDNESDAY.

FOR DTW...TURNING GUSTY OUT OF THE WEST EARLY THIS MORNING AS COLDER
AIR FUNNELS IN.  GUSTS INTO THE 25 KNOT RANGE THROUGHOUT THE MORNING
PERIOD.  POTENTIAL FOR A FEW BRIEF LIGHT SNOW SHOWERS OR FLURRIES
PRIOR TO 12Z WILL BE LIMITED AS THE DEEPER MOISTURE EXITS BEFORE THE
AIR BECOMES COLD ENOUGH.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.

LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     LHZ422-442- 443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 170850
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
350 AM EST WED DEC 17 2014

.SHORT TERM... TODAY AND TONIGHT

AFTER 3 DAYS OF MAX TEMPERATURES IN THE 40S AND LOWER 50S...NORMAL
DECEMBER AIR IS SURGING BACK INTO SE MICHIGAN FOR TODAY. THIS WILL
LIMIT HIGH TEMPERATURES TO THE LOWER AND MID 30S LEADING INTO LOWS
TONIGHT IN THE MID 20S. LIGHT SNOW WILL LINGER NEAR THE TRI CITIES
AND NORTHERN THUMB...MAINLY DURING THE MORNING...WITH LITTLE MORE
THAN A FLURRY OVER THE REST OF SE MICHIGAN.

LIGHT SNOW ONGOING OVER THE SAGINAW VALLEY AND NORTHERN THUMB BEFORE
SUNRISE IS TIED TO AN AXIS OF DEFORMATION IN THE LOW TO MID LEVELS.
THIS FORCING WILL CONTINUE TO SHEAR INTO MORE OF A WEST TO EAST
ORIENTATION DURING THE MORNING WITH THE STRONGEST DYNAMIC FORCING
DISPLACED FROM THE MOISTURE AXIS. THIS WILL MAINTAIN STEADY BUT
LIGHT PRECIPITATION OVER THE NORTHERN GREAT LAKES AND LEAVE THE TRI
CITIES AND NORTHERN THUMB ON THE SOUTHERN FRINGE OF THE PATTERN. AT
THE SAME TIME...DRY AIR WILL CONTINUE TO SLIDE OVER THE REST OF SE
MICHIGAN AS STRONG SUBSIDENCE OCCURS BETWEEN THE DEFORMATION AXIS
ASSOCIATED WITH THE TRAILING UPPER TROUGH AND NORTH FLANK OF THE
UPPER JET AXIS THAT IS CENTERED WELL SOUTH OF THE GREAT LAKES. THIS
WILL ONLY ALLOW WEAK LAKE MICHIGAN ACTIVATION WHICH WILL STRUGGLE TO
MOVE THIS FAR EAST IN ANY FORM GREATER THAN FLURRIES WHILE THE LOW
LEVEL THERMAL TROUGH IS OVERHEAD.

THE UPPER TROUGH WILL SLIDE QUICKLY EASTWARD BY TONIGHT AND LEAVE
TRAILING CYCLONIC OVERHEAD THAT WILL ALLOW A MODEST UPTICK IN
ACTIVITY OFF LAKE MICHIGAN AND HURON EARLY BEFORE WARMER AIR BEGINS
TO MOVE OVER THE SOUTHERN GREAT LAKES. THERE IS GOOD MODEL AGREEMENT
INDICATING 850 MB TEMPERATURE WARMING FROM NEAR -13C AT MID
AFTERNOON TO THE -8C TO -6C RANGE AFTER MIDNIGHT. BOTH THIS AND THE
GENERAL VEERING OF THE LOW LEVEL FLOW WILL KEEP LAKE EFFECT SNOW
SHOWERS OVER SW LOWER AND NORTHERN INDIANA AND PERHAPS JUST BRUSHING
THE NORTHERN THUMB TONIGHT.

&&

.LONG TERM...THURSDAY THROUGH TUESDAY

THE ONLY REAL CONCERN ON THURSDAY WILL BE THE LAKE EFFECT SNOW
SHOWERS BRUSHING THE EASTERN THUMB WITH A NORTH NORTHWEST FLOW OFF
LAKE HURON. WHILE THIS TRAJECTORY IS FAVORABLE FOR SNOWFALL OVER
CANADA...THERE APPEARS TO BE ENOUGH OF A FAVORABLE COMPONENT TO THE
WIND DIRECTION TO MAINTAIN THE CHANCY POPS INHERITED BY THE PREVIOUS
FORECAST. WITH THE MOSTLY UNFAVORABLE TRAJECTORY SNOWFALL
AMOUNTS...IF THERE ARE ANY...WILL BE FAIRLY LIGHT WITH A FEW TENTHS
OF AN INCH POSSIBLE.  HIGH PRESSURE THEN BUILDS IN ACROSS THE GREAT
LAKES REGION ON FRIDAY AS THE MOS GUIDANCE SUGGESTS CLEARING SKIES
LATE THURSDAY NIGHT AND INTO FRIDAY. HOWEVER MODEL SOUNDINGS
INDICATE SUBSIDENCE FROM THE HIGH WILL ONCE AGAIN TRAP MOISTURE
BETWEEN 900 AND 950 MB WHICH WILL MEAN LOW STRATUS WILL ONCE AGAIN
PLAGUE THE CENTRAL GREAT LAKES REGION.  THEREFORE BACKED OFF ON THE
CLEARING SKIES DURING THIS PERIOD AND WENT MORE PESSIMISTIC THAN THE
PREVIOUS FORECAST.

THIS HIGH WILL KEEP THE CENTRAL GREAT LAKES DRY DURING THE WEEKEND
AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE SOUTHEASTERN CONUS.
ALTHOUGH THE SUPER BLEND PAINTS CHANCY POPS ACROSS MUCH OF THE
CWA...MAINLY SATURDAY AND SATURDAY NIGHT...THE NWP MODELS KEEP
THINGS DRY WITH THE AFOREMENTIONED DRY HIGH PRESSURE IN PLACE.
GIVEN THE WET BIAS OF THE SUPER BLEND WILL REMOVE POPS DURING THE
WEEKEND AND GO WITH A DRY FORECAST.  NEAR NORMAL TEMPERATURES ARE
EXPECTED DURING THIS TIME WITH HIGHS IN THE LOW TO MID 30S AND LOWS
IN THE MIDDLE TO UPPER 20S.

THE NEXT SYSTEM OF CONSEQUENCE DEVELOPS OVER THE NORTHERN PLAINS ON
MONDAY AND TRACKS OVER THE WESTERN GREAT LAKES ON TUESDAY.  THIS
SYSTEM LOOKS TO HAVE FAIRLY GOOD DYNAMICS WITH A DEEP 500 MB TROUGH
AND A DECENT LOW LEVEL JET.  IT LOOKS LIKE SOUTHEAST MICHIGAN WILL
BE ON THE WARM SIDE OF THIS SYSTEM ON TUESDAY...WITH MAINLY LIQUID
PRECIPITATION EXPECTED AT THIS POINT IN THE FORECAST.

&&

.MARINE...

COLD AIR ADVECTION AND STRONG WESTERLY WINDS ARE INCREASING IN THE
WAKE OF A COLD FRONT THAT PASSED THROUGH THE CENTRAL GREAT LAKES
EARLY THIS MORNING. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO
THE STRONGEST FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT
THAT LEVEL. IT SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS
DOWN THOUGH WITH SUSTAINED FLOW PUSHING 20 KNOTS. WILL CONTINUE
SMALL CRAFT ADVISORIES FOR ALL NEARSHORE ZONES FOR THESE ELEVATED
WINDS. WAVES WILL ALSO REACH CRITERIA IN SOME OF THE LAKE HURON
ZONES BUT OFFSHORE FLOW WILL KEEP WAVE HEIGHTS DOWN SOMEWHAT ALONG
WITH SOME ICE COVER SHOWING UP IN INNER SAGINAW BAY. WINDS WILL
DECREASE BELOW CRITERIA THIS AFTERNOON BUT WILL STAY ELEVATED
THROUGH TONIGHT AS THEY VEER TO THE NORTHWEST. ALTHOUGH WINDS WILL
FALL BELOW CRITERIA...THE CONTINUED FETCH OFF LAKE HURON WITH THE
NORTHWEST WINDS WILL MAINTAIN HIGHER WAVES THROUGH TONIGHT ACROSS
OUTER SAGINAW BAY AND LAKE HURON FROM PORT AUSTIN TO HARBOR BEACH.
WINDS AND WAVES WILL CONTINUE TO SLOWLY CALM AS HIGH PRESSURE
BUILDS IN ACROSS THE CENTRAL GREAT LAKES THURSDAY AND FRIDAY.

&&

.AVIATION...ISSUED 1154 PM EST TUE DEC 16 2014

//DISCUSSION...

COLD FRONT WILL CONTINUE THROUGH SOUTHEAST MICHIGAN EARLY THIS
MORNING.  A GUSTY POST-COLD FRONTAL WESTERLY WIND WILL EMERGE DURING
THIS TIME...PEAK GUSTS CLIMBING INTO THE 25 KNOT RANGE THROUGHOUT
THE MORNING PERIOD.  THE ENSUING COLD AIR ADVECTION WILL ALLOW ANY
LAGGING IFR CEILING HEIGHTS TO LIFT INTO MVFR.  RECENT RADAR TRENDS
SUGGEST A PERIOD OF LIGHT SNOW WILL BE POSSIBLE AS THE BACK EDGE OF
THE DEEPER MOISTURE LIFTS THROUGH...GREATEST POTENTIAL AT MBS/FNT.
EXTENSIVE STRATUS DECK WILL TRANSITION TOWARD A HIGH MVFR/LOW VFR
CEILING ON WEDNESDAY.

FOR DTW...TURNING GUSTY OUT OF THE WEST EARLY THIS MORNING AS COLDER
AIR FUNNELS IN.  GUSTS INTO THE 25 KNOT RANGE THROUGHOUT THE MORNING
PERIOD.  POTENTIAL FOR A FEW BRIEF LIGHT SNOW SHOWERS OR FLURRIES
PRIOR TO 12Z WILL BE LIMITED AS THE DEEPER MOISTURE EXITS BEFORE THE
AIR BECOMES COLD ENOUGH.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.

LAKE HURON...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     LHZ422-442- 443.

     SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR LHZ421-441.

LAKE ST CLAIR...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LEZ444.

&&

$$

SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI
AVIATION.....MR


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 170454
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1154 PM EST TUE DEC 16 2014

.AVIATION...

//DISCUSSION...

COLD FRONT WILL CONTINUE THROUGH SOUTHEAST MICHIGAN EARLY THIS
MORNING.  A GUSTY POST-COLD FRONTAL WESTERLY WIND WILL EMERGE DURING
THIS TIME...PEAK GUSTS CLIMBING INTO THE 25 KNOT RANGE THROUGHOUT
THE MORNING PERIOD.  THE ENSUING COLD AIR ADVECTION WILL ALLOW ANY
LAGGING IFR CEILING HEIGHTS TO LIFT INTO MVFR.  RECENT RADAR TRENDS
SUGGEST A PERIOD OF LIGHT SNOW WILL BE POSSIBLE AS THE BACK EDGE OF
THE DEEPER MOISTURE LIFTS THROUGH...GREATEST POTENTIAL AT MBS/FNT.
EXTENSIVE STRATUS DECK WILL TRANSITION TOWARD A HIGH MVFR/LOW VFR
CEILING ON WEDNESDAY.

FOR DTW...TURNING GUSTY OUT OF THE WEST EARLY THIS MORNING AS COLDER
AIR FUNNELS IN.  GUSTS INTO THE 25 KNOT RANGE THROUGHOUT THE MORNING
PERIOD.  POTENTIAL FOR A FEW BRIEF LIGHT SNOW SHOWERS OR FLURRIES
PRIOR TO 12Z WILL BE LIMITED AS THE DEEPER MOISTURE EXITS BEFORE THE
AIR BECOMES COLD ENOUGH.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY.

&&

.PREV DISCUSSION...ISSUED 951 PM EST TUE DEC 16 2014

UPDATE...

POCKETS OF LIGHT SHOWERS CONTINUE TO PIVOT THROUGH SE MICHIGAN THIS
EVENING...PRIMARILY ANCHORED ALONG THE LINEAR AXIS OF A WEAKENING
LEAD SHORTWAVE WORKING THROUGH THE EXISTING DEEP LOW LEVEL MOISTURE
PROFILE.  TRAILING WING OF CYCLONIC VORTICITY ADVECTION LEADING IN
THE SOUTHEAST EXTENSION OF THE MAIN CLOSED CIRCULATION NOW OVER
MINNESOTA MARKING THE EDGE OF A SECONDARY AREA OF LIGHT SNOW ACROSS
CENTRAL LAKE MI/NORTHEAST WISCONSIN.   INBOUND COLD FRONT REMAINS ON
SCHEDULE TO SHIFT THROUGH THE AREA OVER THE NEXT 3-5 HOURS...ENSUING
COLD AIR ADVECTION TAKING HOLD THROUGH THE MORNING PERIOD.  CURRENT
PLACEMENT AND DOWNSTREAM MOVEMENT OF THE EXISTING MOISTURE PLUME
DOES CONTINUE TO POINT TOWARD SIMPLY A NARROW WINDOW LATE TONIGHT
FOR A TRANSITION TO LIGHT SNOW BEFORE BOTH THE UNDERLYING FORCING
AND DEEPER MOISTURE WRAP TO THE NORTH AND EAST. ACCUMULATION
POTENTIAL OF LESS THAN AN INCH...FOCUSED ACROSS THE TRI-CITIES AND
NORTHERN THUMB. GOING FORECAST LARGELY ON TRACK WITH THIS
IDEA...MINOR UPDATE FORTHCOMING TO FRESHEN THE WORDING PER LATEST
TEMPERATURE AND PRECIPITATION TRENDS.

PREV DISCUSSION...ISSUED 352 PM EST TUE DEC 16 2014

SHORT TERM... THIS EVENING AND TONIGHT

THE WIDESPREAD RAIN WHICH HAS AFFECTED MUCH OF THE SRN AND ERN
PORTIONS OF SE MI TODAY WILL CONTINUE TO SLOWLY ROTATE EAST OF METRO
DETROIT AND PORT HURON DURING THE REMAINDER OF THE AFTERNOON.
ADDITIONAL SHOWERS NOW ROTATING INTO THE AREA FROM THE WEST ARE
OCCURRING WITHIN ENHANCED LARGE SCALE ASCENT AHEAD OF A SHORT WAVE
SLIDING ACROSS CENTRAL LAKE MI. THERE ALSO APPEARS TO BE SOME
INTERACTION WITH THE UPPER TROUGH OVER THE ERN GREAT LAKES...LEADING
TO INCREASING MID LEVEL DEFORMATION ACROSS SE MI. THE SHORT WAVE IS
FORECAST TO DAMPEN AS IT ROTATES INTO SE MI THIS EVENING...WHILE THE
LONGER WAVELENGTH TROUGH LIFTS NORTH. THE UPPER LOW NOW OVER
MINNESOTA WILL BE THE FEATURE WHICH DRIVES THESE FORCING MECHANISM
NORTH AS IT ADVANCES ACROSS THE WRN GREAT LAKES TONIGHT. THE NET
RESULT WILL BE A SHIFTING OF THE BETTER LARGER SCALE FORCING AND
SHOWER COVERAGE TOWARD THE NORTHERN HALF OF THE FORECAST AREA DURING
THE COURSE OF THE EVENING.

THE SURFACE LOW AND ASSOCIATED OCCLUDED FRONT /LOCATED OVER THE
THUMB REGION AS OF 19Z/ WILL BE FORCED INTO THE SRN BASIN OF LAKE
HURON THIS EVENING...THEN NORTHEAST TO ONTARIO OVERNIGHT. THE 19Z
SURFACE OBSERVATIONS DO SHOW THE COLD AIR LAGGING WELL BEHIND THE
SURFACE LOW...WITH A SECONDARY COLD FRONT STILL ALONG THE WRN SHORE
OF LOWER MI. THIS FRONT WILL NOT PUSH INTO SE MI UNTIL MUCH LATER
THIS EVENING /03Z TO 06Z/. SOME SEMBLANCE OF AN ISSALOBARIC
COMPONENT ALONG THE FRONT AND ARRIVAL OF COLD AIR WILL LEAD TO
INCREASING WINDS. LOW LEVEL COLD AIR ADVECTION THROUGH THE NIGHT
WILL ALSO DEEPEN THE MIXED LAYER AND WILL BE SUPPORTIVE OF SOME
GUSTS UP TO 30 MPH DURING THE OVERNIGHT. AS TEMPS COOL
OVERNIGHT...THE COLUMN WILL BECOME COLD ENOUGH TO SUPPORT ALL SNOW.
A LINGERING THERMAL TROUGH ACROSS THE TRI CITIES AND THUMB SUGGEST
IT WILL TAKE THIS REGION /ALSO THE AREA TO SEE PRECIP PERSIST INTO
THE OVERNIGHT/ BETWEEN 06Z AND 09Z FOR THE COLUMN TO COOL ENOUGH TO
SUPPORT ALL SNOW. THIS WILL BE ALONG THE LEADING EDGE OF DRIER MID
LEVEL AIR AND THUS END OF PRECIP. SO THE CURRENT FORECAST SUGGESTING
A MINIMAL AMOUNT OF SNOW ACCUMS OVERNIGHT ACROSS THE SAGINAW VALLEY
AND THUMB CONTINUES TO LOOK REASONABLE.

LONG TERM...WEDNESDAY THROUGH MONDAY

THE WELL DISCUSSED STACKED LOW PRESSURE SYSTEM WILL BE EXITING TO
THE EAST ON WEDNESDAY BUT A STRONG NORTHERN STREAM PV ANOMALY WILL
BE SHEARING OUT AS IT DIGS DOWN AND THE AROUND THE BACKSIDE OF THE
TROUGH THROUGH SOUTHERN MI. IN ADDITION...LINGERING TROUGH AXIS WILL
BE DRAPED ACROSS CENTRAL/NORTHERN MI BEHIND THE EXITING LOW. A MID
LEVEL COLD POOL...APPROACHING -27C AT 500MB...WILL ACCOMPANY THE VORT
MAX ACROSS SOUTHERN MI DURING THE EVENING HOURS BEHIND AN ARCTIC
FRONT. THE FRONT WILL LOWER FROM ABOUT 500MB OVER MBS TO CLOSER TO
700MB BY THE TIME IT EXITS THE EASTERN CWA...WHILE LOSING SOME
FORCING. THIS SHOULD NOT AMOUNT TO MUCH AT THE SFC BECAUSE MOISTURE
WILL BE LACKING OVER THE AREA WITH DRY AIR BUILDING IN QUICKLY FROM
THE TOP DOWN THROUGH THE PROFILE AS RIDGING BUILDS IN BEHIND THE
UPPER LOW. PWATS WILL BE AROUND 0.4 INCHES WITH SPECIFIC HUMIDITIES
COMING IN MAINLY AROUND 1 G/KG AND ALL BELOW THE INVERSION CENTERED
AROUND 850MB. THIS WILL ALL LEAD TO ANOTHER DAY WITH AMPLE LL CLOUD
COVER AND MUCH COOLER HIGH TEMPS AS WESTERLY WINDS RAMP UP IN THE
WAKE OF THE SFC COLD FRONT. WITH LITTLE MOISTURE TO WORK WITH...DO
NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOWFALL ALTHOUGH
FLURRIES OR LIGHT SNOW SHOWERS WILL BE PREVALENT THROUGH THE EVENING
WITH SOME DEGREE OF LAKE EFFECT KICKING IN. THE WILL BE MORE
CONFINED ACROSS THE FAR NORTH ALTHOUGH SOME HIRES MODELS ARE TRYING
TO SHOW A BAND DEVELOPING LATER IN THE DAY BETWEEN M59 AND I94. THIS
REMAINS TO BE SEEN WITH THE POOR CONVERGENT SIGNATURE SO WILL NOT
HIGHLIGHT ANY POTENTIAL FOR ACCUMS ACROSS THE AREA. THE ACTIVITY
WILL SHUT OFF OVERNIGHT WEDNESDAY EXCEPT FOR THE EASTERN THUMB WHERE
THE MAIN LAKE HURON BAND LOOKS TO BRUSH THOSE COUNTIES...WHICH WILL
LINGER INTO THURSDAY. GUSTY W/NW FLOW WILL PERSIST WEDNESDAY INTO
THURSDAY. OVERALL THE SNOW THREAT IS LOW AND TEMPERATURES WILL
RETURN TO NEAR NORMAL FOR MID DECEMBER WITH HIGHS IN THE LOW/MID
30S AND LOWS IN THE MID 20S.

SOUTHERN STREAM JET WILL SPARK LOW PRESSURE IN THE LOWER MISSISSIPPI
VALLEY FRIDAY THAT SHOULD REMAIN WELL SOUTH OF MICHIGAN AS IT MOVES
NORTHEAST THROUGH THE TENNESSEE VALLEY. AN UPPER LEVEL TROUGH WILL
GENERALLY KEEP COOL TEMPS IN THE FORECAST...BUT SURFACE HIGH
PRESSURE WILL ENSURE DRY CONDITIONS. THIS PATTERN WILL REMAIN IN
PLACE THROUGH THE WEEKEND. 170 KT JET AND MOISTURE COMING ONSHORE IN
THE PACIFIC EARLY NEXT WEEK MAY EVENTUALLY REACH MICHIGAN TOWARD DAY
7.

MARINE...

THE CENTER OF THE SFC LOW IS NOW OVER THE EASTERN GREAT LAKES AND
WILL CONTINUE ITS PUSH EAST THROUGH THE OVERNIGHT. THIS WILL OPEN
THE DOOR FOR STRONG WESTERLY FLOW WITH COLD AIR ADVECTION ACROSS THE
LAKES. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO THE STRONGEST
FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT THAT LEVEL. IT
SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS DOWN THOUGH
WITH SUSTAINED FLOW PUSHING 20 KNOTS. HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE ZONES STARTING WITH LAKE ERIE THIS
EVENING...FOLLOWED BY THE LAKE HURON ZONES AND LAKE ST CLAIR LATE
TONIGHT FOR THESE ELEVATED WINDS. WAVES WILL ALSO REACH CRITERIA IN
SOME OF THE LAKE HURON ZONES BUT OFFSHORE FLOW WILL KEEP WAVE
HEIGHTS DOWN SOMEWHAT ALONG WITH SOME ICE COVER SHOWING UP IN INNER
SAGINAW BAY. WINDS WILL DECREASE BELOW CRITERIA WEDNESDAY AFTERNOON
BUT WILL STAY ELEVATED THROUGH WEDNESDAY NIGHT AS THE VEER TO THE
NORTHWEST.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LHZ421-422-
     441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST WEDNESDAY FOR LEZ444.

&&

$$

AVIATION.....MR
UPDATE.......MR
SHORT TERM...SC
LONG TERM....DRK/MM
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 170454
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1154 PM EST TUE DEC 16 2014

.AVIATION...

//DISCUSSION...

COLD FRONT WILL CONTINUE THROUGH SOUTHEAST MICHIGAN EARLY THIS
MORNING.  A GUSTY POST-COLD FRONTAL WESTERLY WIND WILL EMERGE DURING
THIS TIME...PEAK GUSTS CLIMBING INTO THE 25 KNOT RANGE THROUGHOUT
THE MORNING PERIOD.  THE ENSUING COLD AIR ADVECTION WILL ALLOW ANY
LAGGING IFR CEILING HEIGHTS TO LIFT INTO MVFR.  RECENT RADAR TRENDS
SUGGEST A PERIOD OF LIGHT SNOW WILL BE POSSIBLE AS THE BACK EDGE OF
THE DEEPER MOISTURE LIFTS THROUGH...GREATEST POTENTIAL AT MBS/FNT.
EXTENSIVE STRATUS DECK WILL TRANSITION TOWARD A HIGH MVFR/LOW VFR
CEILING ON WEDNESDAY.

FOR DTW...TURNING GUSTY OUT OF THE WEST EARLY THIS MORNING AS COLDER
AIR FUNNELS IN.  GUSTS INTO THE 25 KNOT RANGE THROUGHOUT THE MORNING
PERIOD.  POTENTIAL FOR A FEW BRIEF LIGHT SNOW SHOWERS OR FLURRIES
PRIOR TO 12Z WILL BE LIMITED AS THE DEEPER MOISTURE EXITS BEFORE THE
AIR BECOMES COLD ENOUGH.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY.

&&

.PREV DISCUSSION...ISSUED 951 PM EST TUE DEC 16 2014

UPDATE...

POCKETS OF LIGHT SHOWERS CONTINUE TO PIVOT THROUGH SE MICHIGAN THIS
EVENING...PRIMARILY ANCHORED ALONG THE LINEAR AXIS OF A WEAKENING
LEAD SHORTWAVE WORKING THROUGH THE EXISTING DEEP LOW LEVEL MOISTURE
PROFILE.  TRAILING WING OF CYCLONIC VORTICITY ADVECTION LEADING IN
THE SOUTHEAST EXTENSION OF THE MAIN CLOSED CIRCULATION NOW OVER
MINNESOTA MARKING THE EDGE OF A SECONDARY AREA OF LIGHT SNOW ACROSS
CENTRAL LAKE MI/NORTHEAST WISCONSIN.   INBOUND COLD FRONT REMAINS ON
SCHEDULE TO SHIFT THROUGH THE AREA OVER THE NEXT 3-5 HOURS...ENSUING
COLD AIR ADVECTION TAKING HOLD THROUGH THE MORNING PERIOD.  CURRENT
PLACEMENT AND DOWNSTREAM MOVEMENT OF THE EXISTING MOISTURE PLUME
DOES CONTINUE TO POINT TOWARD SIMPLY A NARROW WINDOW LATE TONIGHT
FOR A TRANSITION TO LIGHT SNOW BEFORE BOTH THE UNDERLYING FORCING
AND DEEPER MOISTURE WRAP TO THE NORTH AND EAST. ACCUMULATION
POTENTIAL OF LESS THAN AN INCH...FOCUSED ACROSS THE TRI-CITIES AND
NORTHERN THUMB. GOING FORECAST LARGELY ON TRACK WITH THIS
IDEA...MINOR UPDATE FORTHCOMING TO FRESHEN THE WORDING PER LATEST
TEMPERATURE AND PRECIPITATION TRENDS.

PREV DISCUSSION...ISSUED 352 PM EST TUE DEC 16 2014

SHORT TERM... THIS EVENING AND TONIGHT

THE WIDESPREAD RAIN WHICH HAS AFFECTED MUCH OF THE SRN AND ERN
PORTIONS OF SE MI TODAY WILL CONTINUE TO SLOWLY ROTATE EAST OF METRO
DETROIT AND PORT HURON DURING THE REMAINDER OF THE AFTERNOON.
ADDITIONAL SHOWERS NOW ROTATING INTO THE AREA FROM THE WEST ARE
OCCURRING WITHIN ENHANCED LARGE SCALE ASCENT AHEAD OF A SHORT WAVE
SLIDING ACROSS CENTRAL LAKE MI. THERE ALSO APPEARS TO BE SOME
INTERACTION WITH THE UPPER TROUGH OVER THE ERN GREAT LAKES...LEADING
TO INCREASING MID LEVEL DEFORMATION ACROSS SE MI. THE SHORT WAVE IS
FORECAST TO DAMPEN AS IT ROTATES INTO SE MI THIS EVENING...WHILE THE
LONGER WAVELENGTH TROUGH LIFTS NORTH. THE UPPER LOW NOW OVER
MINNESOTA WILL BE THE FEATURE WHICH DRIVES THESE FORCING MECHANISM
NORTH AS IT ADVANCES ACROSS THE WRN GREAT LAKES TONIGHT. THE NET
RESULT WILL BE A SHIFTING OF THE BETTER LARGER SCALE FORCING AND
SHOWER COVERAGE TOWARD THE NORTHERN HALF OF THE FORECAST AREA DURING
THE COURSE OF THE EVENING.

THE SURFACE LOW AND ASSOCIATED OCCLUDED FRONT /LOCATED OVER THE
THUMB REGION AS OF 19Z/ WILL BE FORCED INTO THE SRN BASIN OF LAKE
HURON THIS EVENING...THEN NORTHEAST TO ONTARIO OVERNIGHT. THE 19Z
SURFACE OBSERVATIONS DO SHOW THE COLD AIR LAGGING WELL BEHIND THE
SURFACE LOW...WITH A SECONDARY COLD FRONT STILL ALONG THE WRN SHORE
OF LOWER MI. THIS FRONT WILL NOT PUSH INTO SE MI UNTIL MUCH LATER
THIS EVENING /03Z TO 06Z/. SOME SEMBLANCE OF AN ISSALOBARIC
COMPONENT ALONG THE FRONT AND ARRIVAL OF COLD AIR WILL LEAD TO
INCREASING WINDS. LOW LEVEL COLD AIR ADVECTION THROUGH THE NIGHT
WILL ALSO DEEPEN THE MIXED LAYER AND WILL BE SUPPORTIVE OF SOME
GUSTS UP TO 30 MPH DURING THE OVERNIGHT. AS TEMPS COOL
OVERNIGHT...THE COLUMN WILL BECOME COLD ENOUGH TO SUPPORT ALL SNOW.
A LINGERING THERMAL TROUGH ACROSS THE TRI CITIES AND THUMB SUGGEST
IT WILL TAKE THIS REGION /ALSO THE AREA TO SEE PRECIP PERSIST INTO
THE OVERNIGHT/ BETWEEN 06Z AND 09Z FOR THE COLUMN TO COOL ENOUGH TO
SUPPORT ALL SNOW. THIS WILL BE ALONG THE LEADING EDGE OF DRIER MID
LEVEL AIR AND THUS END OF PRECIP. SO THE CURRENT FORECAST SUGGESTING
A MINIMAL AMOUNT OF SNOW ACCUMS OVERNIGHT ACROSS THE SAGINAW VALLEY
AND THUMB CONTINUES TO LOOK REASONABLE.

LONG TERM...WEDNESDAY THROUGH MONDAY

THE WELL DISCUSSED STACKED LOW PRESSURE SYSTEM WILL BE EXITING TO
THE EAST ON WEDNESDAY BUT A STRONG NORTHERN STREAM PV ANOMALY WILL
BE SHEARING OUT AS IT DIGS DOWN AND THE AROUND THE BACKSIDE OF THE
TROUGH THROUGH SOUTHERN MI. IN ADDITION...LINGERING TROUGH AXIS WILL
BE DRAPED ACROSS CENTRAL/NORTHERN MI BEHIND THE EXITING LOW. A MID
LEVEL COLD POOL...APPROACHING -27C AT 500MB...WILL ACCOMPANY THE VORT
MAX ACROSS SOUTHERN MI DURING THE EVENING HOURS BEHIND AN ARCTIC
FRONT. THE FRONT WILL LOWER FROM ABOUT 500MB OVER MBS TO CLOSER TO
700MB BY THE TIME IT EXITS THE EASTERN CWA...WHILE LOSING SOME
FORCING. THIS SHOULD NOT AMOUNT TO MUCH AT THE SFC BECAUSE MOISTURE
WILL BE LACKING OVER THE AREA WITH DRY AIR BUILDING IN QUICKLY FROM
THE TOP DOWN THROUGH THE PROFILE AS RIDGING BUILDS IN BEHIND THE
UPPER LOW. PWATS WILL BE AROUND 0.4 INCHES WITH SPECIFIC HUMIDITIES
COMING IN MAINLY AROUND 1 G/KG AND ALL BELOW THE INVERSION CENTERED
AROUND 850MB. THIS WILL ALL LEAD TO ANOTHER DAY WITH AMPLE LL CLOUD
COVER AND MUCH COOLER HIGH TEMPS AS WESTERLY WINDS RAMP UP IN THE
WAKE OF THE SFC COLD FRONT. WITH LITTLE MOISTURE TO WORK WITH...DO
NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOWFALL ALTHOUGH
FLURRIES OR LIGHT SNOW SHOWERS WILL BE PREVALENT THROUGH THE EVENING
WITH SOME DEGREE OF LAKE EFFECT KICKING IN. THE WILL BE MORE
CONFINED ACROSS THE FAR NORTH ALTHOUGH SOME HIRES MODELS ARE TRYING
TO SHOW A BAND DEVELOPING LATER IN THE DAY BETWEEN M59 AND I94. THIS
REMAINS TO BE SEEN WITH THE POOR CONVERGENT SIGNATURE SO WILL NOT
HIGHLIGHT ANY POTENTIAL FOR ACCUMS ACROSS THE AREA. THE ACTIVITY
WILL SHUT OFF OVERNIGHT WEDNESDAY EXCEPT FOR THE EASTERN THUMB WHERE
THE MAIN LAKE HURON BAND LOOKS TO BRUSH THOSE COUNTIES...WHICH WILL
LINGER INTO THURSDAY. GUSTY W/NW FLOW WILL PERSIST WEDNESDAY INTO
THURSDAY. OVERALL THE SNOW THREAT IS LOW AND TEMPERATURES WILL
RETURN TO NEAR NORMAL FOR MID DECEMBER WITH HIGHS IN THE LOW/MID
30S AND LOWS IN THE MID 20S.

SOUTHERN STREAM JET WILL SPARK LOW PRESSURE IN THE LOWER MISSISSIPPI
VALLEY FRIDAY THAT SHOULD REMAIN WELL SOUTH OF MICHIGAN AS IT MOVES
NORTHEAST THROUGH THE TENNESSEE VALLEY. AN UPPER LEVEL TROUGH WILL
GENERALLY KEEP COOL TEMPS IN THE FORECAST...BUT SURFACE HIGH
PRESSURE WILL ENSURE DRY CONDITIONS. THIS PATTERN WILL REMAIN IN
PLACE THROUGH THE WEEKEND. 170 KT JET AND MOISTURE COMING ONSHORE IN
THE PACIFIC EARLY NEXT WEEK MAY EVENTUALLY REACH MICHIGAN TOWARD DAY
7.

MARINE...

THE CENTER OF THE SFC LOW IS NOW OVER THE EASTERN GREAT LAKES AND
WILL CONTINUE ITS PUSH EAST THROUGH THE OVERNIGHT. THIS WILL OPEN
THE DOOR FOR STRONG WESTERLY FLOW WITH COLD AIR ADVECTION ACROSS THE
LAKES. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO THE STRONGEST
FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT THAT LEVEL. IT
SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS DOWN THOUGH
WITH SUSTAINED FLOW PUSHING 20 KNOTS. HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE ZONES STARTING WITH LAKE ERIE THIS
EVENING...FOLLOWED BY THE LAKE HURON ZONES AND LAKE ST CLAIR LATE
TONIGHT FOR THESE ELEVATED WINDS. WAVES WILL ALSO REACH CRITERIA IN
SOME OF THE LAKE HURON ZONES BUT OFFSHORE FLOW WILL KEEP WAVE
HEIGHTS DOWN SOMEWHAT ALONG WITH SOME ICE COVER SHOWING UP IN INNER
SAGINAW BAY. WINDS WILL DECREASE BELOW CRITERIA WEDNESDAY AFTERNOON
BUT WILL STAY ELEVATED THROUGH WEDNESDAY NIGHT AS THE VEER TO THE
NORTHWEST.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LHZ421-422-
     441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST WEDNESDAY FOR LEZ444.

&&

$$

AVIATION.....MR
UPDATE.......MR
SHORT TERM...SC
LONG TERM....DRK/MM
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 170454
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1154 PM EST TUE DEC 16 2014

.AVIATION...

//DISCUSSION...

COLD FRONT WILL CONTINUE THROUGH SOUTHEAST MICHIGAN EARLY THIS
MORNING.  A GUSTY POST-COLD FRONTAL WESTERLY WIND WILL EMERGE DURING
THIS TIME...PEAK GUSTS CLIMBING INTO THE 25 KNOT RANGE THROUGHOUT
THE MORNING PERIOD.  THE ENSUING COLD AIR ADVECTION WILL ALLOW ANY
LAGGING IFR CEILING HEIGHTS TO LIFT INTO MVFR.  RECENT RADAR TRENDS
SUGGEST A PERIOD OF LIGHT SNOW WILL BE POSSIBLE AS THE BACK EDGE OF
THE DEEPER MOISTURE LIFTS THROUGH...GREATEST POTENTIAL AT MBS/FNT.
EXTENSIVE STRATUS DECK WILL TRANSITION TOWARD A HIGH MVFR/LOW VFR
CEILING ON WEDNESDAY.

FOR DTW...TURNING GUSTY OUT OF THE WEST EARLY THIS MORNING AS COLDER
AIR FUNNELS IN.  GUSTS INTO THE 25 KNOT RANGE THROUGHOUT THE MORNING
PERIOD.  POTENTIAL FOR A FEW BRIEF LIGHT SNOW SHOWERS OR FLURRIES
PRIOR TO 12Z WILL BE LIMITED AS THE DEEPER MOISTURE EXITS BEFORE THE
AIR BECOMES COLD ENOUGH.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY.

&&

.PREV DISCUSSION...ISSUED 951 PM EST TUE DEC 16 2014

UPDATE...

POCKETS OF LIGHT SHOWERS CONTINUE TO PIVOT THROUGH SE MICHIGAN THIS
EVENING...PRIMARILY ANCHORED ALONG THE LINEAR AXIS OF A WEAKENING
LEAD SHORTWAVE WORKING THROUGH THE EXISTING DEEP LOW LEVEL MOISTURE
PROFILE.  TRAILING WING OF CYCLONIC VORTICITY ADVECTION LEADING IN
THE SOUTHEAST EXTENSION OF THE MAIN CLOSED CIRCULATION NOW OVER
MINNESOTA MARKING THE EDGE OF A SECONDARY AREA OF LIGHT SNOW ACROSS
CENTRAL LAKE MI/NORTHEAST WISCONSIN.   INBOUND COLD FRONT REMAINS ON
SCHEDULE TO SHIFT THROUGH THE AREA OVER THE NEXT 3-5 HOURS...ENSUING
COLD AIR ADVECTION TAKING HOLD THROUGH THE MORNING PERIOD.  CURRENT
PLACEMENT AND DOWNSTREAM MOVEMENT OF THE EXISTING MOISTURE PLUME
DOES CONTINUE TO POINT TOWARD SIMPLY A NARROW WINDOW LATE TONIGHT
FOR A TRANSITION TO LIGHT SNOW BEFORE BOTH THE UNDERLYING FORCING
AND DEEPER MOISTURE WRAP TO THE NORTH AND EAST. ACCUMULATION
POTENTIAL OF LESS THAN AN INCH...FOCUSED ACROSS THE TRI-CITIES AND
NORTHERN THUMB. GOING FORECAST LARGELY ON TRACK WITH THIS
IDEA...MINOR UPDATE FORTHCOMING TO FRESHEN THE WORDING PER LATEST
TEMPERATURE AND PRECIPITATION TRENDS.

PREV DISCUSSION...ISSUED 352 PM EST TUE DEC 16 2014

SHORT TERM... THIS EVENING AND TONIGHT

THE WIDESPREAD RAIN WHICH HAS AFFECTED MUCH OF THE SRN AND ERN
PORTIONS OF SE MI TODAY WILL CONTINUE TO SLOWLY ROTATE EAST OF METRO
DETROIT AND PORT HURON DURING THE REMAINDER OF THE AFTERNOON.
ADDITIONAL SHOWERS NOW ROTATING INTO THE AREA FROM THE WEST ARE
OCCURRING WITHIN ENHANCED LARGE SCALE ASCENT AHEAD OF A SHORT WAVE
SLIDING ACROSS CENTRAL LAKE MI. THERE ALSO APPEARS TO BE SOME
INTERACTION WITH THE UPPER TROUGH OVER THE ERN GREAT LAKES...LEADING
TO INCREASING MID LEVEL DEFORMATION ACROSS SE MI. THE SHORT WAVE IS
FORECAST TO DAMPEN AS IT ROTATES INTO SE MI THIS EVENING...WHILE THE
LONGER WAVELENGTH TROUGH LIFTS NORTH. THE UPPER LOW NOW OVER
MINNESOTA WILL BE THE FEATURE WHICH DRIVES THESE FORCING MECHANISM
NORTH AS IT ADVANCES ACROSS THE WRN GREAT LAKES TONIGHT. THE NET
RESULT WILL BE A SHIFTING OF THE BETTER LARGER SCALE FORCING AND
SHOWER COVERAGE TOWARD THE NORTHERN HALF OF THE FORECAST AREA DURING
THE COURSE OF THE EVENING.

THE SURFACE LOW AND ASSOCIATED OCCLUDED FRONT /LOCATED OVER THE
THUMB REGION AS OF 19Z/ WILL BE FORCED INTO THE SRN BASIN OF LAKE
HURON THIS EVENING...THEN NORTHEAST TO ONTARIO OVERNIGHT. THE 19Z
SURFACE OBSERVATIONS DO SHOW THE COLD AIR LAGGING WELL BEHIND THE
SURFACE LOW...WITH A SECONDARY COLD FRONT STILL ALONG THE WRN SHORE
OF LOWER MI. THIS FRONT WILL NOT PUSH INTO SE MI UNTIL MUCH LATER
THIS EVENING /03Z TO 06Z/. SOME SEMBLANCE OF AN ISSALOBARIC
COMPONENT ALONG THE FRONT AND ARRIVAL OF COLD AIR WILL LEAD TO
INCREASING WINDS. LOW LEVEL COLD AIR ADVECTION THROUGH THE NIGHT
WILL ALSO DEEPEN THE MIXED LAYER AND WILL BE SUPPORTIVE OF SOME
GUSTS UP TO 30 MPH DURING THE OVERNIGHT. AS TEMPS COOL
OVERNIGHT...THE COLUMN WILL BECOME COLD ENOUGH TO SUPPORT ALL SNOW.
A LINGERING THERMAL TROUGH ACROSS THE TRI CITIES AND THUMB SUGGEST
IT WILL TAKE THIS REGION /ALSO THE AREA TO SEE PRECIP PERSIST INTO
THE OVERNIGHT/ BETWEEN 06Z AND 09Z FOR THE COLUMN TO COOL ENOUGH TO
SUPPORT ALL SNOW. THIS WILL BE ALONG THE LEADING EDGE OF DRIER MID
LEVEL AIR AND THUS END OF PRECIP. SO THE CURRENT FORECAST SUGGESTING
A MINIMAL AMOUNT OF SNOW ACCUMS OVERNIGHT ACROSS THE SAGINAW VALLEY
AND THUMB CONTINUES TO LOOK REASONABLE.

LONG TERM...WEDNESDAY THROUGH MONDAY

THE WELL DISCUSSED STACKED LOW PRESSURE SYSTEM WILL BE EXITING TO
THE EAST ON WEDNESDAY BUT A STRONG NORTHERN STREAM PV ANOMALY WILL
BE SHEARING OUT AS IT DIGS DOWN AND THE AROUND THE BACKSIDE OF THE
TROUGH THROUGH SOUTHERN MI. IN ADDITION...LINGERING TROUGH AXIS WILL
BE DRAPED ACROSS CENTRAL/NORTHERN MI BEHIND THE EXITING LOW. A MID
LEVEL COLD POOL...APPROACHING -27C AT 500MB...WILL ACCOMPANY THE VORT
MAX ACROSS SOUTHERN MI DURING THE EVENING HOURS BEHIND AN ARCTIC
FRONT. THE FRONT WILL LOWER FROM ABOUT 500MB OVER MBS TO CLOSER TO
700MB BY THE TIME IT EXITS THE EASTERN CWA...WHILE LOSING SOME
FORCING. THIS SHOULD NOT AMOUNT TO MUCH AT THE SFC BECAUSE MOISTURE
WILL BE LACKING OVER THE AREA WITH DRY AIR BUILDING IN QUICKLY FROM
THE TOP DOWN THROUGH THE PROFILE AS RIDGING BUILDS IN BEHIND THE
UPPER LOW. PWATS WILL BE AROUND 0.4 INCHES WITH SPECIFIC HUMIDITIES
COMING IN MAINLY AROUND 1 G/KG AND ALL BELOW THE INVERSION CENTERED
AROUND 850MB. THIS WILL ALL LEAD TO ANOTHER DAY WITH AMPLE LL CLOUD
COVER AND MUCH COOLER HIGH TEMPS AS WESTERLY WINDS RAMP UP IN THE
WAKE OF THE SFC COLD FRONT. WITH LITTLE MOISTURE TO WORK WITH...DO
NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOWFALL ALTHOUGH
FLURRIES OR LIGHT SNOW SHOWERS WILL BE PREVALENT THROUGH THE EVENING
WITH SOME DEGREE OF LAKE EFFECT KICKING IN. THE WILL BE MORE
CONFINED ACROSS THE FAR NORTH ALTHOUGH SOME HIRES MODELS ARE TRYING
TO SHOW A BAND DEVELOPING LATER IN THE DAY BETWEEN M59 AND I94. THIS
REMAINS TO BE SEEN WITH THE POOR CONVERGENT SIGNATURE SO WILL NOT
HIGHLIGHT ANY POTENTIAL FOR ACCUMS ACROSS THE AREA. THE ACTIVITY
WILL SHUT OFF OVERNIGHT WEDNESDAY EXCEPT FOR THE EASTERN THUMB WHERE
THE MAIN LAKE HURON BAND LOOKS TO BRUSH THOSE COUNTIES...WHICH WILL
LINGER INTO THURSDAY. GUSTY W/NW FLOW WILL PERSIST WEDNESDAY INTO
THURSDAY. OVERALL THE SNOW THREAT IS LOW AND TEMPERATURES WILL
RETURN TO NEAR NORMAL FOR MID DECEMBER WITH HIGHS IN THE LOW/MID
30S AND LOWS IN THE MID 20S.

SOUTHERN STREAM JET WILL SPARK LOW PRESSURE IN THE LOWER MISSISSIPPI
VALLEY FRIDAY THAT SHOULD REMAIN WELL SOUTH OF MICHIGAN AS IT MOVES
NORTHEAST THROUGH THE TENNESSEE VALLEY. AN UPPER LEVEL TROUGH WILL
GENERALLY KEEP COOL TEMPS IN THE FORECAST...BUT SURFACE HIGH
PRESSURE WILL ENSURE DRY CONDITIONS. THIS PATTERN WILL REMAIN IN
PLACE THROUGH THE WEEKEND. 170 KT JET AND MOISTURE COMING ONSHORE IN
THE PACIFIC EARLY NEXT WEEK MAY EVENTUALLY REACH MICHIGAN TOWARD DAY
7.

MARINE...

THE CENTER OF THE SFC LOW IS NOW OVER THE EASTERN GREAT LAKES AND
WILL CONTINUE ITS PUSH EAST THROUGH THE OVERNIGHT. THIS WILL OPEN
THE DOOR FOR STRONG WESTERLY FLOW WITH COLD AIR ADVECTION ACROSS THE
LAKES. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO THE STRONGEST
FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT THAT LEVEL. IT
SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS DOWN THOUGH
WITH SUSTAINED FLOW PUSHING 20 KNOTS. HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE ZONES STARTING WITH LAKE ERIE THIS
EVENING...FOLLOWED BY THE LAKE HURON ZONES AND LAKE ST CLAIR LATE
TONIGHT FOR THESE ELEVATED WINDS. WAVES WILL ALSO REACH CRITERIA IN
SOME OF THE LAKE HURON ZONES BUT OFFSHORE FLOW WILL KEEP WAVE
HEIGHTS DOWN SOMEWHAT ALONG WITH SOME ICE COVER SHOWING UP IN INNER
SAGINAW BAY. WINDS WILL DECREASE BELOW CRITERIA WEDNESDAY AFTERNOON
BUT WILL STAY ELEVATED THROUGH WEDNESDAY NIGHT AS THE VEER TO THE
NORTHWEST.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LHZ421-422-
     441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST WEDNESDAY FOR LEZ444.

&&

$$

AVIATION.....MR
UPDATE.......MR
SHORT TERM...SC
LONG TERM....DRK/MM
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 170454
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1154 PM EST TUE DEC 16 2014

.AVIATION...

//DISCUSSION...

COLD FRONT WILL CONTINUE THROUGH SOUTHEAST MICHIGAN EARLY THIS
MORNING.  A GUSTY POST-COLD FRONTAL WESTERLY WIND WILL EMERGE DURING
THIS TIME...PEAK GUSTS CLIMBING INTO THE 25 KNOT RANGE THROUGHOUT
THE MORNING PERIOD.  THE ENSUING COLD AIR ADVECTION WILL ALLOW ANY
LAGGING IFR CEILING HEIGHTS TO LIFT INTO MVFR.  RECENT RADAR TRENDS
SUGGEST A PERIOD OF LIGHT SNOW WILL BE POSSIBLE AS THE BACK EDGE OF
THE DEEPER MOISTURE LIFTS THROUGH...GREATEST POTENTIAL AT MBS/FNT.
EXTENSIVE STRATUS DECK WILL TRANSITION TOWARD A HIGH MVFR/LOW VFR
CEILING ON WEDNESDAY.

FOR DTW...TURNING GUSTY OUT OF THE WEST EARLY THIS MORNING AS COLDER
AIR FUNNELS IN.  GUSTS INTO THE 25 KNOT RANGE THROUGHOUT THE MORNING
PERIOD.  POTENTIAL FOR A FEW BRIEF LIGHT SNOW SHOWERS OR FLURRIES
PRIOR TO 12Z WILL BE LIMITED AS THE DEEPER MOISTURE EXITS BEFORE THE
AIR BECOMES COLD ENOUGH.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY.

&&

.PREV DISCUSSION...ISSUED 951 PM EST TUE DEC 16 2014

UPDATE...

POCKETS OF LIGHT SHOWERS CONTINUE TO PIVOT THROUGH SE MICHIGAN THIS
EVENING...PRIMARILY ANCHORED ALONG THE LINEAR AXIS OF A WEAKENING
LEAD SHORTWAVE WORKING THROUGH THE EXISTING DEEP LOW LEVEL MOISTURE
PROFILE.  TRAILING WING OF CYCLONIC VORTICITY ADVECTION LEADING IN
THE SOUTHEAST EXTENSION OF THE MAIN CLOSED CIRCULATION NOW OVER
MINNESOTA MARKING THE EDGE OF A SECONDARY AREA OF LIGHT SNOW ACROSS
CENTRAL LAKE MI/NORTHEAST WISCONSIN.   INBOUND COLD FRONT REMAINS ON
SCHEDULE TO SHIFT THROUGH THE AREA OVER THE NEXT 3-5 HOURS...ENSUING
COLD AIR ADVECTION TAKING HOLD THROUGH THE MORNING PERIOD.  CURRENT
PLACEMENT AND DOWNSTREAM MOVEMENT OF THE EXISTING MOISTURE PLUME
DOES CONTINUE TO POINT TOWARD SIMPLY A NARROW WINDOW LATE TONIGHT
FOR A TRANSITION TO LIGHT SNOW BEFORE BOTH THE UNDERLYING FORCING
AND DEEPER MOISTURE WRAP TO THE NORTH AND EAST. ACCUMULATION
POTENTIAL OF LESS THAN AN INCH...FOCUSED ACROSS THE TRI-CITIES AND
NORTHERN THUMB. GOING FORECAST LARGELY ON TRACK WITH THIS
IDEA...MINOR UPDATE FORTHCOMING TO FRESHEN THE WORDING PER LATEST
TEMPERATURE AND PRECIPITATION TRENDS.

PREV DISCUSSION...ISSUED 352 PM EST TUE DEC 16 2014

SHORT TERM... THIS EVENING AND TONIGHT

THE WIDESPREAD RAIN WHICH HAS AFFECTED MUCH OF THE SRN AND ERN
PORTIONS OF SE MI TODAY WILL CONTINUE TO SLOWLY ROTATE EAST OF METRO
DETROIT AND PORT HURON DURING THE REMAINDER OF THE AFTERNOON.
ADDITIONAL SHOWERS NOW ROTATING INTO THE AREA FROM THE WEST ARE
OCCURRING WITHIN ENHANCED LARGE SCALE ASCENT AHEAD OF A SHORT WAVE
SLIDING ACROSS CENTRAL LAKE MI. THERE ALSO APPEARS TO BE SOME
INTERACTION WITH THE UPPER TROUGH OVER THE ERN GREAT LAKES...LEADING
TO INCREASING MID LEVEL DEFORMATION ACROSS SE MI. THE SHORT WAVE IS
FORECAST TO DAMPEN AS IT ROTATES INTO SE MI THIS EVENING...WHILE THE
LONGER WAVELENGTH TROUGH LIFTS NORTH. THE UPPER LOW NOW OVER
MINNESOTA WILL BE THE FEATURE WHICH DRIVES THESE FORCING MECHANISM
NORTH AS IT ADVANCES ACROSS THE WRN GREAT LAKES TONIGHT. THE NET
RESULT WILL BE A SHIFTING OF THE BETTER LARGER SCALE FORCING AND
SHOWER COVERAGE TOWARD THE NORTHERN HALF OF THE FORECAST AREA DURING
THE COURSE OF THE EVENING.

THE SURFACE LOW AND ASSOCIATED OCCLUDED FRONT /LOCATED OVER THE
THUMB REGION AS OF 19Z/ WILL BE FORCED INTO THE SRN BASIN OF LAKE
HURON THIS EVENING...THEN NORTHEAST TO ONTARIO OVERNIGHT. THE 19Z
SURFACE OBSERVATIONS DO SHOW THE COLD AIR LAGGING WELL BEHIND THE
SURFACE LOW...WITH A SECONDARY COLD FRONT STILL ALONG THE WRN SHORE
OF LOWER MI. THIS FRONT WILL NOT PUSH INTO SE MI UNTIL MUCH LATER
THIS EVENING /03Z TO 06Z/. SOME SEMBLANCE OF AN ISSALOBARIC
COMPONENT ALONG THE FRONT AND ARRIVAL OF COLD AIR WILL LEAD TO
INCREASING WINDS. LOW LEVEL COLD AIR ADVECTION THROUGH THE NIGHT
WILL ALSO DEEPEN THE MIXED LAYER AND WILL BE SUPPORTIVE OF SOME
GUSTS UP TO 30 MPH DURING THE OVERNIGHT. AS TEMPS COOL
OVERNIGHT...THE COLUMN WILL BECOME COLD ENOUGH TO SUPPORT ALL SNOW.
A LINGERING THERMAL TROUGH ACROSS THE TRI CITIES AND THUMB SUGGEST
IT WILL TAKE THIS REGION /ALSO THE AREA TO SEE PRECIP PERSIST INTO
THE OVERNIGHT/ BETWEEN 06Z AND 09Z FOR THE COLUMN TO COOL ENOUGH TO
SUPPORT ALL SNOW. THIS WILL BE ALONG THE LEADING EDGE OF DRIER MID
LEVEL AIR AND THUS END OF PRECIP. SO THE CURRENT FORECAST SUGGESTING
A MINIMAL AMOUNT OF SNOW ACCUMS OVERNIGHT ACROSS THE SAGINAW VALLEY
AND THUMB CONTINUES TO LOOK REASONABLE.

LONG TERM...WEDNESDAY THROUGH MONDAY

THE WELL DISCUSSED STACKED LOW PRESSURE SYSTEM WILL BE EXITING TO
THE EAST ON WEDNESDAY BUT A STRONG NORTHERN STREAM PV ANOMALY WILL
BE SHEARING OUT AS IT DIGS DOWN AND THE AROUND THE BACKSIDE OF THE
TROUGH THROUGH SOUTHERN MI. IN ADDITION...LINGERING TROUGH AXIS WILL
BE DRAPED ACROSS CENTRAL/NORTHERN MI BEHIND THE EXITING LOW. A MID
LEVEL COLD POOL...APPROACHING -27C AT 500MB...WILL ACCOMPANY THE VORT
MAX ACROSS SOUTHERN MI DURING THE EVENING HOURS BEHIND AN ARCTIC
FRONT. THE FRONT WILL LOWER FROM ABOUT 500MB OVER MBS TO CLOSER TO
700MB BY THE TIME IT EXITS THE EASTERN CWA...WHILE LOSING SOME
FORCING. THIS SHOULD NOT AMOUNT TO MUCH AT THE SFC BECAUSE MOISTURE
WILL BE LACKING OVER THE AREA WITH DRY AIR BUILDING IN QUICKLY FROM
THE TOP DOWN THROUGH THE PROFILE AS RIDGING BUILDS IN BEHIND THE
UPPER LOW. PWATS WILL BE AROUND 0.4 INCHES WITH SPECIFIC HUMIDITIES
COMING IN MAINLY AROUND 1 G/KG AND ALL BELOW THE INVERSION CENTERED
AROUND 850MB. THIS WILL ALL LEAD TO ANOTHER DAY WITH AMPLE LL CLOUD
COVER AND MUCH COOLER HIGH TEMPS AS WESTERLY WINDS RAMP UP IN THE
WAKE OF THE SFC COLD FRONT. WITH LITTLE MOISTURE TO WORK WITH...DO
NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOWFALL ALTHOUGH
FLURRIES OR LIGHT SNOW SHOWERS WILL BE PREVALENT THROUGH THE EVENING
WITH SOME DEGREE OF LAKE EFFECT KICKING IN. THE WILL BE MORE
CONFINED ACROSS THE FAR NORTH ALTHOUGH SOME HIRES MODELS ARE TRYING
TO SHOW A BAND DEVELOPING LATER IN THE DAY BETWEEN M59 AND I94. THIS
REMAINS TO BE SEEN WITH THE POOR CONVERGENT SIGNATURE SO WILL NOT
HIGHLIGHT ANY POTENTIAL FOR ACCUMS ACROSS THE AREA. THE ACTIVITY
WILL SHUT OFF OVERNIGHT WEDNESDAY EXCEPT FOR THE EASTERN THUMB WHERE
THE MAIN LAKE HURON BAND LOOKS TO BRUSH THOSE COUNTIES...WHICH WILL
LINGER INTO THURSDAY. GUSTY W/NW FLOW WILL PERSIST WEDNESDAY INTO
THURSDAY. OVERALL THE SNOW THREAT IS LOW AND TEMPERATURES WILL
RETURN TO NEAR NORMAL FOR MID DECEMBER WITH HIGHS IN THE LOW/MID
30S AND LOWS IN THE MID 20S.

SOUTHERN STREAM JET WILL SPARK LOW PRESSURE IN THE LOWER MISSISSIPPI
VALLEY FRIDAY THAT SHOULD REMAIN WELL SOUTH OF MICHIGAN AS IT MOVES
NORTHEAST THROUGH THE TENNESSEE VALLEY. AN UPPER LEVEL TROUGH WILL
GENERALLY KEEP COOL TEMPS IN THE FORECAST...BUT SURFACE HIGH
PRESSURE WILL ENSURE DRY CONDITIONS. THIS PATTERN WILL REMAIN IN
PLACE THROUGH THE WEEKEND. 170 KT JET AND MOISTURE COMING ONSHORE IN
THE PACIFIC EARLY NEXT WEEK MAY EVENTUALLY REACH MICHIGAN TOWARD DAY
7.

MARINE...

THE CENTER OF THE SFC LOW IS NOW OVER THE EASTERN GREAT LAKES AND
WILL CONTINUE ITS PUSH EAST THROUGH THE OVERNIGHT. THIS WILL OPEN
THE DOOR FOR STRONG WESTERLY FLOW WITH COLD AIR ADVECTION ACROSS THE
LAKES. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO THE STRONGEST
FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT THAT LEVEL. IT
SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS DOWN THOUGH
WITH SUSTAINED FLOW PUSHING 20 KNOTS. HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE ZONES STARTING WITH LAKE ERIE THIS
EVENING...FOLLOWED BY THE LAKE HURON ZONES AND LAKE ST CLAIR LATE
TONIGHT FOR THESE ELEVATED WINDS. WAVES WILL ALSO REACH CRITERIA IN
SOME OF THE LAKE HURON ZONES BUT OFFSHORE FLOW WILL KEEP WAVE
HEIGHTS DOWN SOMEWHAT ALONG WITH SOME ICE COVER SHOWING UP IN INNER
SAGINAW BAY. WINDS WILL DECREASE BELOW CRITERIA WEDNESDAY AFTERNOON
BUT WILL STAY ELEVATED THROUGH WEDNESDAY NIGHT AS THE VEER TO THE
NORTHWEST.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LHZ421-422-
     441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST WEDNESDAY FOR LEZ444.

&&

$$

AVIATION.....MR
UPDATE.......MR
SHORT TERM...SC
LONG TERM....DRK/MM
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 170251
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
951 PM EST TUE DEC 16 2014

.UPDATE...

POCKETS OF LIGHT SHOWERS CONTINUE TO PIVOT THROUGH SE MICHIGAN THIS
EVENING...PRIMARILY ANCHORED ALONG THE LINEAR AXIS OF A WEAKENING
LEAD SHORTWAVE WORKING THROUGH THE EXISTING DEEP LOW LEVEL MOISTURE
PROFILE.  TRAILING WING OF CYCLONIC VORTICITY ADVECTION LEADING IN
THE SOUTHEAST EXTENSION OF THE MAIN CLOSED CIRCULATION NOW OVER
MINNESOTA MARKING THE EDGE OF A SECONDARY AREA OF LIGHT SNOW ACROSS
CENTRAL LAKE MI/NORTHEAST WISCONSIN.   INBOUND COLD FRONT REMAINS ON
SCHEDULE TO SHIFT THROUGH THE AREA OVER THE NEXT 3-5 HOURS...ENSUING
COLD AIR ADVECTION TAKING HOLD THROUGH THE MORNING PERIOD.  CURRENT
PLACEMENT AND DOWNSTREAM MOVEMENT OF THE EXISTING MOISTURE PLUME
DOES CONTINUE TO POINT TOWARD SIMPLY A NARROW WINDOW LATE TONIGHT
FOR A TRANSITION TO LIGHT SNOW BEFORE BOTH THE UNDERLYING FORCING
AND DEEPER MOISTURE WRAP TO THE NORTH AND EAST. ACCUMULATION
POTENTIAL OF LESS THAN AN INCH...FOCUSED ACROSS THE TRI-CITIES AND
NORTHERN THUMB. GOING FORECAST LARGELY ON TRACK WITH THIS
IDEA...MINOR UPDATE FORTHCOMING TO FRESHEN THE WORDING PER LATEST
TEMPERATURE AND PRECIPITATION TRENDS.

&&

.AVIATION...ISSUED 616 PM EST TUE DEC 16 2014

//DISCUSSION...

MOIST LOW LEVEL CONDITIONS CONTAINED WITHIN A MODEST PRE-FRONTAL
SOUTHWEST FLOW WILL MAINTAIN A PERIOD OF IFR CONDITIONS THROUGHOUT
SE MICHIGAN THIS EVENING.  POCKETS OF LIGHT RAIN WILL CONTRIBUTE TO
SOME VISIBILITY REDUCTIONS /3-5 SM/ IN ADDITION TO THE LOW CEILING
HEIGHTS.  THE ENSUING ARRIVAL OF COLDER AIR WITH THE FRONTAL PASSAGE
/03Z-04Z/ WILL LIFT CONDITIONS INTO MVFR FOR THE EARLY MORNING
PERIOD.  THIS PROCESS WILL ALSO RESULT IN AN INCREASE IN WESTERLY
WINDS.  PEAK GUSTS IN THE 25 KNOT RANGE THROUGHOUT THE MORNING
HOURS.

FOR DTW...SUBSTANTIAL AREA OF IFR STRATUS WILL SHIFT THROUGH THE
TERMINAL AIRSPACE THROUGH THE LATTER HALF OF THE EVENING.  CEILINGS
WILL THEN BEGIN TO LIFT AS COLDER AIR ARRIVES AFTER 05Z.  THIS WILL
ALSO REMOVE ANY LINGERING FOG/VISIBILITY RESTRICTIONS.  MVFR LEVEL
CIGS HOLD THROUGH THE MORNING PERIOD.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY
  MORNING.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS ALL RAIN.

&&

.PREV DISCUSSION...ISSUED 352 PM EST TUE DEC 16 2014

SHORT TERM... THIS EVENING AND TONIGHT

THE WIDESPREAD RAIN WHICH HAS AFFECTED MUCH OF THE SRN AND ERN
PORTIONS OF SE MI TODAY WILL CONTINUE TO SLOWLY ROTATE EAST OF METRO
DETROIT AND PORT HURON DURING THE REMAINDER OF THE AFTERNOON.
ADDITIONAL SHOWERS NOW ROTATING INTO THE AREA FROM THE WEST ARE
OCCURRING WITHIN ENHANCED LARGE SCALE ASCENT AHEAD OF A SHORT WAVE
SLIDING ACROSS CENTRAL LAKE MI. THERE ALSO APPEARS TO BE SOME
INTERACTION WITH THE UPPER TROUGH OVER THE ERN GREAT LAKES...LEADING
TO INCREASING MID LEVEL DEFORMATION ACROSS SE MI. THE SHORT WAVE IS
FORECAST TO DAMPEN AS IT ROTATES INTO SE MI THIS EVENING...WHILE THE
LONGER WAVELENGTH TROUGH LIFTS NORTH. THE UPPER LOW NOW OVER
MINNESOTA WILL BE THE FEATURE WHICH DRIVES THESE FORCING MECHANISM
NORTH AS IT ADVANCES ACROSS THE WRN GREAT LAKES TONIGHT. THE NET
RESULT WILL BE A SHIFTING OF THE BETTER LARGER SCALE FORCING AND
SHOWER COVERAGE TOWARD THE NORTHERN HALF OF THE FORECAST AREA DURING
THE COURSE OF THE EVENING.

THE SURFACE LOW AND ASSOCIATED OCCLUDED FRONT /LOCATED OVER THE
THUMB REGION AS OF 19Z/ WILL BE FORCED INTO THE SRN BASIN OF LAKE
HURON THIS EVENING...THEN NORTHEAST TO ONTARIO OVERNIGHT. THE 19Z
SURFACE OBSERVATIONS DO SHOW THE COLD AIR LAGGING WELL BEHIND THE
SURFACE LOW...WITH A SECONDARY COLD FRONT STILL ALONG THE WRN SHORE
OF LOWER MI. THIS FRONT WILL NOT PUSH INTO SE MI UNTIL MUCH LATER
THIS EVENING /03Z TO 06Z/. SOME SEMBLANCE OF AN ISSALOBARIC
COMPONENT ALONG THE FRONT AND ARRIVAL OF COLD AIR WILL LEAD TO
INCREASING WINDS. LOW LEVEL COLD AIR ADVECTION THROUGH THE NIGHT
WILL ALSO DEEPEN THE MIXED LAYER AND WILL BE SUPPORTIVE OF SOME
GUSTS UP TO 30 MPH DURING THE OVERNIGHT. AS TEMPS COOL
OVERNIGHT...THE COLUMN WILL BECOME COLD ENOUGH TO SUPPORT ALL SNOW.
A LINGERING THERMAL TROUGH ACROSS THE TRI CITIES AND THUMB SUGGEST
IT WILL TAKE THIS REGION /ALSO THE AREA TO SEE PRECIP PERSIST INTO
THE OVERNIGHT/ BETWEEN 06Z AND 09Z FOR THE COLUMN TO COOL ENOUGH TO
SUPPORT ALL SNOW. THIS WILL BE ALONG THE LEADING EDGE OF DRIER MID
LEVEL AIR AND THUS END OF PRECIP. SO THE CURRENT FORECAST SUGGESTING
A MINIMAL AMOUNT OF SNOW ACCUMS OVERNIGHT ACROSS THE SAGINAW VALLEY
AND THUMB CONTINUES TO LOOK REASONABLE.

LONG TERM...WEDNESDAY THROUGH MONDAY

THE WELL DISCUSSED STACKED LOW PRESSURE SYSTEM WILL BE EXITING TO
THE EAST ON WEDNESDAY BUT A STRONG NORTHERN STREAM PV ANOMALY WILL
BE SHEARING OUT AS IT DIGS DOWN AND THE AROUND THE BACKSIDE OF THE
TROUGH THROUGH SOUTHERN MI. IN ADDITION...LINGERING TROUGH AXIS WILL
BE DRAPED ACROSS CENTRAL/NORTHERN MI BEHIND THE EXITING LOW. A MID
LEVEL COLD POOL...APPROACHING -27C AT 500MB...WILL ACCOMPANY THE VORT
MAX ACROSS SOUTHERN MI DURING THE EVENING HOURS BEHIND AN ARCTIC
FRONT. THE FRONT WILL LOWER FROM ABOUT 500MB OVER MBS TO CLOSER TO
700MB BY THE TIME IT EXITS THE EASTERN CWA...WHILE LOSING SOME
FORCING. THIS SHOULD NOT AMOUNT TO MUCH AT THE SFC BECAUSE MOISTURE
WILL BE LACKING OVER THE AREA WITH DRY AIR BUILDING IN QUICKLY FROM
THE TOP DOWN THROUGH THE PROFILE AS RIDGING BUILDS IN BEHIND THE
UPPER LOW. PWATS WILL BE AROUND 0.4 INCHES WITH SPECIFIC HUMIDITIES
COMING IN MAINLY AROUND 1 G/KG AND ALL BELOW THE INVERSION CENTERED
AROUND 850MB. THIS WILL ALL LEAD TO ANOTHER DAY WITH AMPLE LL CLOUD
COVER AND MUCH COOLER HIGH TEMPS AS WESTERLY WINDS RAMP UP IN THE
WAKE OF THE SFC COLD FRONT. WITH LITTLE MOISTURE TO WORK WITH...DO
NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOWFALL ALTHOUGH
FLURRIES OR LIGHT SNOW SHOWERS WILL BE PREVALENT THROUGH THE EVENING
WITH SOME DEGREE OF LAKE EFFECT KICKING IN. THE WILL BE MORE
CONFINED ACROSS THE FAR NORTH ALTHOUGH SOME HIRES MODELS ARE TRYING
TO SHOW A BAND DEVELOPING LATER IN THE DAY BETWEEN M59 AND I94. THIS
REMAINS TO BE SEEN WITH THE POOR CONVERGENT SIGNATURE SO WILL NOT
HIGHLIGHT ANY POTENTIAL FOR ACCUMS ACROSS THE AREA. THE ACTIVITY
WILL SHUT OFF OVERNIGHT WEDNESDAY EXCEPT FOR THE EASTERN THUMB WHERE
THE MAIN LAKE HURON BAND LOOKS TO BRUSH THOSE COUNTIES...WHICH WILL
LINGER INTO THURSDAY. GUSTY W/NW FLOW WILL PERSIST WEDNESDAY INTO
THURSDAY. OVERALL THE SNOW THREAT IS LOW AND TEMPERATURES WILL
RETURN TO NEAR NORMAL FOR MID DECEMBER WITH HIGHS IN THE LOW/MID
30S AND LOWS IN THE MID 20S.

SOUTHERN STREAM JET WILL SPARK LOW PRESSURE IN THE LOWER MISSISSIPPI
VALLEY FRIDAY THAT SHOULD REMAIN WELL SOUTH OF MICHIGAN AS IT MOVES
NORTHEAST THROUGH THE TENNESSEE VALLEY. AN UPPER LEVEL TROUGH WILL
GENERALLY KEEP COOL TEMPS IN THE FORECAST...BUT SURFACE HIGH
PRESSURE WILL ENSURE DRY CONDITIONS. THIS PATTERN WILL REMAIN IN
PLACE THROUGH THE WEEKEND. 170 KT JET AND MOISTURE COMING ONSHORE IN
THE PACIFIC EARLY NEXT WEEK MAY EVENTUALLY REACH MICHIGAN TOWARD DAY
7.

MARINE...

THE CENTER OF THE SFC LOW IS NOW OVER THE EASTERN GREAT LAKES AND
WILL CONTINUE ITS PUSH EAST THROUGH THE OVERNIGHT. THIS WILL OPEN
THE DOOR FOR STRONG WESTERLY FLOW WITH COLD AIR ADVECTION ACROSS THE
LAKES. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO THE STRONGEST
FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT THAT LEVEL. IT
SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS DOWN THOUGH
WITH SUSTAINED FLOW PUSHING 20 KNOTS. HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE ZONES STARTING WITH LAKE ERIE THIS
EVENING...FOLLOWED BY THE LAKE HURON ZONES AND LAKE ST CLAIR LATE
TONIGHT FOR THESE ELEVATED WINDS. WAVES WILL ALSO REACH CRITERIA IN
SOME OF THE LAKE HURON ZONES BUT OFFSHORE FLOW WILL KEEP WAVE
HEIGHTS DOWN SOMEWHAT ALONG WITH SOME ICE COVER SHOWING UP IN INNER
SAGINAW BAY. WINDS WILL DECREASE BELOW CRITERIA WEDNESDAY AFTERNOON
BUT WILL STAY ELEVATED THROUGH WEDNESDAY NIGHT AS THE VEER TO THE
NORTHWEST.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LHZ421-422-
     441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY UNTIL 4 PM EST WEDNESDAY FOR LEZ444.

&&

$$

UPDATE.......MR
AVIATION.....MR
SHORT TERM...SC
LONG TERM....DRK/MM
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 162316
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
616 PM EST TUE DEC 16 2014

.AVIATION...

//DISCUSSION...

MOIST LOW LEVEL CONDITIONS CONTAINED WITHIN A MODEST PRE-FRONTAL
SOUTHWEST FLOW WILL MAINTAIN A PERIOD OF IFR CONDITIONS THROUGHOUT
SE MICHIGAN THIS EVENING.  POCKETS OF LIGHT RAIN WILL CONTRIBUTE TO
SOME VISIBILITY REDUCTIONS /3-5 SM/ IN ADDITION TO THE LOW CEILING
HEIGHTS.  THE ENSUING ARRIVAL OF COLDER AIR WITH THE FRONTAL PASSAGE
/03Z-04Z/ WILL LIFT CONDITIONS INTO MVFR FOR THE EARLY MORNING
PERIOD.  THIS PROCESS WILL ALSO RESULT IN AN INCREASE IN WESTERLY
WINDS.  PEAK GUSTS IN THE 25 KNOT RANGE THROUGHOUT THE MORNING
HOURS.

FOR DTW...SUBSTANTIAL AREA OF IFR STRATUS WILL SHIFT THROUGH THE
TERMINAL AIRSPACE THROUGH THE LATTER HALF OF THE EVENING.  CEILINGS
WILL THEN BEGIN TO LIFT AS COLDER AIR ARRIVES AFTER 05Z.  THIS WILL
ALSO REMOVE ANY LINGERING FOG/VISIBILITY RESTRICTIONS.  MVFR LEVEL
CIGS HOLD THROUGH THE MORNING PERIOD.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY
  MORNING.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS ALL RAIN.

&&

.PREV DISCUSSION...ISSUED 352 PM EST TUE DEC 16 2014

SHORT TERM... THIS EVENING AND TONIGHT

THE WIDESPREAD RAIN WHICH HAS AFFECTED MUCH OF THE SRN AND ERN
PORTIONS OF SE MI TODAY WILL CONTINUE TO SLOWLY ROTATE EAST OF METRO
DETROIT AND PORT HURON DURING THE REMAINDER OF THE AFTERNOON.
ADDITIONAL SHOWERS NOW ROTATING INTO THE AREA FROM THE WEST ARE
OCCURRING WITHIN ENHANCED LARGE SCALE ASCENT AHEAD OF A SHORT WAVE
SLIDING ACROSS CENTRAL LAKE MI. THERE ALSO APPEARS TO BE SOME
INTERACTION WITH THE UPPER TROUGH OVER THE ERN GREAT LAKES...LEADING
TO INCREASING MID LEVEL DEFORMATION ACROSS SE MI. THE SHORT WAVE IS
FORECAST TO DAMPEN AS IT ROTATES INTO SE MI THIS EVENING...WHILE THE
LONGER WAVELENGTH TROUGH LIFTS NORTH. THE UPPER LOW NOW OVER
MINNESOTA WILL BE THE FEATURE WHICH DRIVES THESE FORCING MECHANISM
NORTH AS IT ADVANCES ACROSS THE WRN GREAT LAKES TONIGHT. THE NET
RESULT WILL BE A SHIFTING OF THE BETTER LARGER SCALE FORCING AND
SHOWER COVERAGE TOWARD THE NORTHERN HALF OF THE FORECAST AREA DURING
THE COURSE OF THE EVENING.

THE SURFACE LOW AND ASSOCIATED OCCLUDED FRONT /LOCATED OVER THE
THUMB REGION AS OF 19Z/ WILL BE FORCED INTO THE SRN BASIN OF LAKE
HURON THIS EVENING...THEN NORTHEAST TO ONTARIO OVERNIGHT. THE 19Z
SURFACE OBSERVATIONS DO SHOW THE COLD AIR LAGGING WELL BEHIND THE
SURFACE LOW...WITH A SECONDARY COLD FRONT STILL ALONG THE WRN SHORE
OF LOWER MI. THIS FRONT WILL NOT PUSH INTO SE MI UNTIL MUCH LATER
THIS EVENING /03Z TO 06Z/. SOME SEMBLANCE OF AN ISSALOBARIC
COMPONENT ALONG THE FRONT AND ARRIVAL OF COLD AIR WILL LEAD TO
INCREASING WINDS. LOW LEVEL COLD AIR ADVECTION THROUGH THE NIGHT
WILL ALSO DEEPEN THE MIXED LAYER AND WILL BE SUPPORTIVE OF SOME
GUSTS UP TO 30 MPH DURING THE OVERNIGHT. AS TEMPS COOL
OVERNIGHT...THE COLUMN WILL BECOME COLD ENOUGH TO SUPPORT ALL SNOW.
A LINGERING THERMAL TROUGH ACROSS THE TRI CITIES AND THUMB SUGGEST
IT WILL TAKE THIS REGION /ALSO THE AREA TO SEE PRECIP PERSIST INTO
THE OVERNIGHT/ BETWEEN 06Z AND 09Z FOR THE COLUMN TO COOL ENOUGH TO
SUPPORT ALL SNOW. THIS WILL BE ALONG THE LEADING EDGE OF DRIER MID
LEVEL AIR AND THUS END OF PRECIP. SO THE CURRENT FORECAST SUGGESTING
A MINIMAL AMOUNT OF SNOW ACCUMS OVERNIGHT ACROSS THE SAGINAW VALLEY
AND THUMB CONTINUES TO LOOK REASONABLE.

LONG TERM...WEDNESDAY THROUGH MONDAY

THE WELL DISCUSSED STACKED LOW PRESSURE SYSTEM WILL BE EXITING TO
THE EAST ON WEDNESDAY BUT A STRONG NORTHERN STREAM PV ANOMALY WILL
BE SHEARING OUT AS IT DIGS DOWN AND THE AROUND THE BACKSIDE OF THE
TROUGH THROUGH SOUTHERN MI. IN ADDITION...LINGERING TROUGH AXIS WILL
BE DRAPED ACROSS CENTRAL/NORTHERN MI BEHIND THE EXITING LOW. A MID
LEVEL COLD POOL...APPROACHING -27C AT 500MB...WILL ACCOMPANY THE VORT
MAX ACROSS SOUTHERN MI DURING THE EVENING HOURS BEHIND AN ARCTIC
FRONT. THE FRONT WILL LOWER FROM ABOUT 500MB OVER MBS TO CLOSER TO
700MB BY THE TIME IT EXITS THE EASTERN CWA...WHILE LOSING SOME
FORCING. THIS SHOULD NOT AMOUNT TO MUCH AT THE SFC BECAUSE MOISTURE
WILL BE LACKING OVER THE AREA WITH DRY AIR BUILDING IN QUICKLY FROM
THE TOP DOWN THROUGH THE PROFILE AS RIDGING BUILDS IN BEHIND THE
UPPER LOW. PWATS WILL BE AROUND 0.4 INCHES WITH SPECIFIC HUMIDITIES
COMING IN MAINLY AROUND 1 G/KG AND ALL BELOW THE INVERSION CENTERED
AROUND 850MB. THIS WILL ALL LEAD TO ANOTHER DAY WITH AMPLE LL CLOUD
COVER AND MUCH COOLER HIGH TEMPS AS WESTERLY WINDS RAMP UP IN THE
WAKE OF THE SFC COLD FRONT. WITH LITTLE MOISTURE TO WORK WITH...DO
NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOWFALL ALTHOUGH
FLURRIES OR LIGHT SNOW SHOWERS WILL BE PREVALENT THROUGH THE EVENING
WITH SOME DEGREE OF LAKE EFFECT KICKING IN. THE WILL BE MORE
CONFINED ACROSS THE FAR NORTH ALTHOUGH SOME HIRES MODELS ARE TRYING
TO SHOW A BAND DEVELOPING LATER IN THE DAY BETWEEN M59 AND I94. THIS
REMAINS TO BE SEEN WITH THE POOR CONVERGENT SIGNATURE SO WILL NOT
HIGHLIGHT ANY POTENTIAL FOR ACCUMS ACROSS THE AREA. THE ACTIVITY
WILL SHUT OFF OVERNIGHT WEDNESDAY EXCEPT FOR THE EASTERN THUMB WHERE
THE MAIN LAKE HURON BAND LOOKS TO BRUSH THOSE COUNTIES...WHICH WILL
LINGER INTO THURSDAY. GUSTY W/NW FLOW WILL PERSIST WEDNESDAY INTO
THURSDAY. OVERALL THE SNOW THREAT IS LOW AND TEMPERATURES WILL
RETURN TO NEAR NORMAL FOR MID DECEMBER WITH HIGHS IN THE LOW/MID
30S AND LOWS IN THE MID 20S.

SOUTHERN STREAM JET WILL SPARK LOW PRESSURE IN THE LOWER MISSISSIPPI
VALLEY FRIDAY THAT SHOULD REMAIN WELL SOUTH OF MICHIGAN AS IT MOVES
NORTHEAST THROUGH THE TENNESSEE VALLEY. AN UPPER LEVEL TROUGH WILL
GENERALLY KEEP COOL TEMPS IN THE FORECAST...BUT SURFACE HIGH
PRESSURE WILL ENSURE DRY CONDITIONS. THIS PATTERN WILL REMAIN IN
PLACE THROUGH THE WEEKEND. 170 KT JET AND MOISTURE COMING ONSHORE IN
THE PACIFIC EARLY NEXT WEEK MAY EVENTUALLY REACH MICHIGAN TOWARD DAY
7.

MARINE...

THE CENTER OF THE SFC LOW IS NOW OVER THE EASTERN GREAT LAKES AND
WILL CONTINUE ITS PUSH EAST THROUGH THE OVERNIGHT. THIS WILL OPEN
THE DOOR FOR STRONG WESTERLY FLOW WITH COLD AIR ADVECTION ACROSS THE
LAKES. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO THE STRONGEST
FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT THAT LEVEL. IT
SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS DOWN THOUGH
WITH SUSTAINED FLOW PUSHING 20 KNOTS. HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE ZONES STARTING WITH LAKE ERIE THIS
EVENING...FOLLOWED BY THE LAKE HURON ZONES AND LAKE ST CLAIR LATE
TONIGHT FOR THESE ELEVATED WINDS. WAVES WILL ALSO REACH CRITERIA IN
SOME OF THE LAKE HURON ZONES BUT OFFSHORE FLOW WILL KEEP WAVE
HEIGHTS DOWN SOMEWHAT ALONG WITH SOME ICE COVER SHOWING UP IN INNER
SAGINAW BAY. WINDS WILL DECREASE BELOW CRITERIA WEDNESDAY AFTERNOON
BUT WILL STAY ELEVATED THROUGH WEDNESDAY NIGHT AS THE VEER TO THE
NORTHWEST.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LHZ421-422-
     441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST WEDNESDAY
     FOR LEZ444.

&&

$$

AVIATION.....MR
SHORT TERM...SC
LONG TERM....DRK/MM
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 162316
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
616 PM EST TUE DEC 16 2014

.AVIATION...

//DISCUSSION...

MOIST LOW LEVEL CONDITIONS CONTAINED WITHIN A MODEST PRE-FRONTAL
SOUTHWEST FLOW WILL MAINTAIN A PERIOD OF IFR CONDITIONS THROUGHOUT
SE MICHIGAN THIS EVENING.  POCKETS OF LIGHT RAIN WILL CONTRIBUTE TO
SOME VISIBILITY REDUCTIONS /3-5 SM/ IN ADDITION TO THE LOW CEILING
HEIGHTS.  THE ENSUING ARRIVAL OF COLDER AIR WITH THE FRONTAL PASSAGE
/03Z-04Z/ WILL LIFT CONDITIONS INTO MVFR FOR THE EARLY MORNING
PERIOD.  THIS PROCESS WILL ALSO RESULT IN AN INCREASE IN WESTERLY
WINDS.  PEAK GUSTS IN THE 25 KNOT RANGE THROUGHOUT THE MORNING
HOURS.

FOR DTW...SUBSTANTIAL AREA OF IFR STRATUS WILL SHIFT THROUGH THE
TERMINAL AIRSPACE THROUGH THE LATTER HALF OF THE EVENING.  CEILINGS
WILL THEN BEGIN TO LIFT AS COLDER AIR ARRIVES AFTER 05Z.  THIS WILL
ALSO REMOVE ANY LINGERING FOG/VISIBILITY RESTRICTIONS.  MVFR LEVEL
CIGS HOLD THROUGH THE MORNING PERIOD.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THROUGH WEDNESDAY
  MORNING.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS ALL RAIN.

&&

.PREV DISCUSSION...ISSUED 352 PM EST TUE DEC 16 2014

SHORT TERM... THIS EVENING AND TONIGHT

THE WIDESPREAD RAIN WHICH HAS AFFECTED MUCH OF THE SRN AND ERN
PORTIONS OF SE MI TODAY WILL CONTINUE TO SLOWLY ROTATE EAST OF METRO
DETROIT AND PORT HURON DURING THE REMAINDER OF THE AFTERNOON.
ADDITIONAL SHOWERS NOW ROTATING INTO THE AREA FROM THE WEST ARE
OCCURRING WITHIN ENHANCED LARGE SCALE ASCENT AHEAD OF A SHORT WAVE
SLIDING ACROSS CENTRAL LAKE MI. THERE ALSO APPEARS TO BE SOME
INTERACTION WITH THE UPPER TROUGH OVER THE ERN GREAT LAKES...LEADING
TO INCREASING MID LEVEL DEFORMATION ACROSS SE MI. THE SHORT WAVE IS
FORECAST TO DAMPEN AS IT ROTATES INTO SE MI THIS EVENING...WHILE THE
LONGER WAVELENGTH TROUGH LIFTS NORTH. THE UPPER LOW NOW OVER
MINNESOTA WILL BE THE FEATURE WHICH DRIVES THESE FORCING MECHANISM
NORTH AS IT ADVANCES ACROSS THE WRN GREAT LAKES TONIGHT. THE NET
RESULT WILL BE A SHIFTING OF THE BETTER LARGER SCALE FORCING AND
SHOWER COVERAGE TOWARD THE NORTHERN HALF OF THE FORECAST AREA DURING
THE COURSE OF THE EVENING.

THE SURFACE LOW AND ASSOCIATED OCCLUDED FRONT /LOCATED OVER THE
THUMB REGION AS OF 19Z/ WILL BE FORCED INTO THE SRN BASIN OF LAKE
HURON THIS EVENING...THEN NORTHEAST TO ONTARIO OVERNIGHT. THE 19Z
SURFACE OBSERVATIONS DO SHOW THE COLD AIR LAGGING WELL BEHIND THE
SURFACE LOW...WITH A SECONDARY COLD FRONT STILL ALONG THE WRN SHORE
OF LOWER MI. THIS FRONT WILL NOT PUSH INTO SE MI UNTIL MUCH LATER
THIS EVENING /03Z TO 06Z/. SOME SEMBLANCE OF AN ISSALOBARIC
COMPONENT ALONG THE FRONT AND ARRIVAL OF COLD AIR WILL LEAD TO
INCREASING WINDS. LOW LEVEL COLD AIR ADVECTION THROUGH THE NIGHT
WILL ALSO DEEPEN THE MIXED LAYER AND WILL BE SUPPORTIVE OF SOME
GUSTS UP TO 30 MPH DURING THE OVERNIGHT. AS TEMPS COOL
OVERNIGHT...THE COLUMN WILL BECOME COLD ENOUGH TO SUPPORT ALL SNOW.
A LINGERING THERMAL TROUGH ACROSS THE TRI CITIES AND THUMB SUGGEST
IT WILL TAKE THIS REGION /ALSO THE AREA TO SEE PRECIP PERSIST INTO
THE OVERNIGHT/ BETWEEN 06Z AND 09Z FOR THE COLUMN TO COOL ENOUGH TO
SUPPORT ALL SNOW. THIS WILL BE ALONG THE LEADING EDGE OF DRIER MID
LEVEL AIR AND THUS END OF PRECIP. SO THE CURRENT FORECAST SUGGESTING
A MINIMAL AMOUNT OF SNOW ACCUMS OVERNIGHT ACROSS THE SAGINAW VALLEY
AND THUMB CONTINUES TO LOOK REASONABLE.

LONG TERM...WEDNESDAY THROUGH MONDAY

THE WELL DISCUSSED STACKED LOW PRESSURE SYSTEM WILL BE EXITING TO
THE EAST ON WEDNESDAY BUT A STRONG NORTHERN STREAM PV ANOMALY WILL
BE SHEARING OUT AS IT DIGS DOWN AND THE AROUND THE BACKSIDE OF THE
TROUGH THROUGH SOUTHERN MI. IN ADDITION...LINGERING TROUGH AXIS WILL
BE DRAPED ACROSS CENTRAL/NORTHERN MI BEHIND THE EXITING LOW. A MID
LEVEL COLD POOL...APPROACHING -27C AT 500MB...WILL ACCOMPANY THE VORT
MAX ACROSS SOUTHERN MI DURING THE EVENING HOURS BEHIND AN ARCTIC
FRONT. THE FRONT WILL LOWER FROM ABOUT 500MB OVER MBS TO CLOSER TO
700MB BY THE TIME IT EXITS THE EASTERN CWA...WHILE LOSING SOME
FORCING. THIS SHOULD NOT AMOUNT TO MUCH AT THE SFC BECAUSE MOISTURE
WILL BE LACKING OVER THE AREA WITH DRY AIR BUILDING IN QUICKLY FROM
THE TOP DOWN THROUGH THE PROFILE AS RIDGING BUILDS IN BEHIND THE
UPPER LOW. PWATS WILL BE AROUND 0.4 INCHES WITH SPECIFIC HUMIDITIES
COMING IN MAINLY AROUND 1 G/KG AND ALL BELOW THE INVERSION CENTERED
AROUND 850MB. THIS WILL ALL LEAD TO ANOTHER DAY WITH AMPLE LL CLOUD
COVER AND MUCH COOLER HIGH TEMPS AS WESTERLY WINDS RAMP UP IN THE
WAKE OF THE SFC COLD FRONT. WITH LITTLE MOISTURE TO WORK WITH...DO
NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOWFALL ALTHOUGH
FLURRIES OR LIGHT SNOW SHOWERS WILL BE PREVALENT THROUGH THE EVENING
WITH SOME DEGREE OF LAKE EFFECT KICKING IN. THE WILL BE MORE
CONFINED ACROSS THE FAR NORTH ALTHOUGH SOME HIRES MODELS ARE TRYING
TO SHOW A BAND DEVELOPING LATER IN THE DAY BETWEEN M59 AND I94. THIS
REMAINS TO BE SEEN WITH THE POOR CONVERGENT SIGNATURE SO WILL NOT
HIGHLIGHT ANY POTENTIAL FOR ACCUMS ACROSS THE AREA. THE ACTIVITY
WILL SHUT OFF OVERNIGHT WEDNESDAY EXCEPT FOR THE EASTERN THUMB WHERE
THE MAIN LAKE HURON BAND LOOKS TO BRUSH THOSE COUNTIES...WHICH WILL
LINGER INTO THURSDAY. GUSTY W/NW FLOW WILL PERSIST WEDNESDAY INTO
THURSDAY. OVERALL THE SNOW THREAT IS LOW AND TEMPERATURES WILL
RETURN TO NEAR NORMAL FOR MID DECEMBER WITH HIGHS IN THE LOW/MID
30S AND LOWS IN THE MID 20S.

SOUTHERN STREAM JET WILL SPARK LOW PRESSURE IN THE LOWER MISSISSIPPI
VALLEY FRIDAY THAT SHOULD REMAIN WELL SOUTH OF MICHIGAN AS IT MOVES
NORTHEAST THROUGH THE TENNESSEE VALLEY. AN UPPER LEVEL TROUGH WILL
GENERALLY KEEP COOL TEMPS IN THE FORECAST...BUT SURFACE HIGH
PRESSURE WILL ENSURE DRY CONDITIONS. THIS PATTERN WILL REMAIN IN
PLACE THROUGH THE WEEKEND. 170 KT JET AND MOISTURE COMING ONSHORE IN
THE PACIFIC EARLY NEXT WEEK MAY EVENTUALLY REACH MICHIGAN TOWARD DAY
7.

MARINE...

THE CENTER OF THE SFC LOW IS NOW OVER THE EASTERN GREAT LAKES AND
WILL CONTINUE ITS PUSH EAST THROUGH THE OVERNIGHT. THIS WILL OPEN
THE DOOR FOR STRONG WESTERLY FLOW WITH COLD AIR ADVECTION ACROSS THE
LAKES. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO THE STRONGEST
FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT THAT LEVEL. IT
SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS DOWN THOUGH
WITH SUSTAINED FLOW PUSHING 20 KNOTS. HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE ZONES STARTING WITH LAKE ERIE THIS
EVENING...FOLLOWED BY THE LAKE HURON ZONES AND LAKE ST CLAIR LATE
TONIGHT FOR THESE ELEVATED WINDS. WAVES WILL ALSO REACH CRITERIA IN
SOME OF THE LAKE HURON ZONES BUT OFFSHORE FLOW WILL KEEP WAVE
HEIGHTS DOWN SOMEWHAT ALONG WITH SOME ICE COVER SHOWING UP IN INNER
SAGINAW BAY. WINDS WILL DECREASE BELOW CRITERIA WEDNESDAY AFTERNOON
BUT WILL STAY ELEVATED THROUGH WEDNESDAY NIGHT AS THE VEER TO THE
NORTHWEST.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LHZ421-422-
     441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST WEDNESDAY
     FOR LEZ444.

&&

$$

AVIATION.....MR
SHORT TERM...SC
LONG TERM....DRK/MM
MARINE.......DRK


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 162052
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
352 PM EST TUE DEC 16 2014

.SHORT TERM... THIS EVENING AND TONIGHT

THE WIDESPREAD RAIN WHICH HAS AFFECTED MUCH OF THE SRN AND ERN
PORTIONS OF SE MI TODAY WILL CONTINUE TO SLOWLY ROTATE EAST OF METRO
DETROIT AND PORT HURON DURING THE REMAINDER OF THE AFTERNOON.
ADDITIONAL SHOWERS NOW ROTATING INTO THE AREA FROM THE WEST ARE
OCCURRING WITHIN ENHANCED LARGE SCALE ASCENT AHEAD OF A SHORT WAVE
SLIDING ACROSS CENTRAL LAKE MI. THERE ALSO APPEARS TO BE SOME
INTERACTION WITH THE UPPER TROUGH OVER THE ERN GREAT LAKES...LEADING
TO INCREASING MID LEVEL DEFORMATION ACROSS SE MI. THE SHORT WAVE IS
FORECAST TO DAMPEN AS IT ROTATES INTO SE MI THIS EVENING...WHILE THE
LONGER WAVELENGTH TROUGH LIFTS NORTH. THE UPPER LOW NOW OVER
MINNESOTA WILL BE THE FEATURE WHICH DRIVES THESE FORCING MECHANISM
NORTH AS IT ADVANCES ACROSS THE WRN GREAT LAKES TONIGHT. THE NET
RESULT WILL BE A SHIFTING OF THE BETTER LARGER SCALE FORCING AND
SHOWER COVERAGE TOWARD THE NORTHERN HALF OF THE FORECAST AREA DURING
THE COURSE OF THE EVENING.

THE SURFACE LOW AND ASSOCIATED OCCLUDED FRONT /LOCATED OVER THE
THUMB REGION AS OF 19Z/ WILL BE FORCED INTO THE SRN BASIN OF LAKE
HURON THIS EVENING...THEN NORTHEAST TO ONTARIO OVERNIGHT. THE 19Z
SURFACE OBSERVATIONS DO SHOW THE COLD AIR LAGGING WELL BEHIND THE
SURFACE LOW...WITH A SECONDARY COLD FRONT STILL ALONG THE WRN SHORE
OF LOWER MI. THIS FRONT WILL NOT PUSH INTO SE MI UNTIL MUCH LATER
THIS EVENING /03Z TO 06Z/. SOME SEMBLANCE OF AN ISSALOBARIC
COMPONENT ALONG THE FRONT AND ARRIVAL OF COLD AIR WILL LEAD TO
INCREASING WINDS. LOW LEVEL COLD AIR ADVECTION THROUGH THE NIGHT
WILL ALSO DEEPEN THE MIXED LAYER AND WILL BE SUPPORTIVE OF SOME
GUSTS UP TO 30 MPH DURING THE OVERNIGHT. AS TEMPS COOL
OVERNIGHT...THE COLUMN WILL BECOME COLD ENOUGH TO SUPPORT ALL SNOW.
A LINGERING THERMAL TROUGH ACROSS THE TRI CITIES AND THUMB SUGGEST
IT WILL TAKE THIS REGION /ALSO THE AREA TO SEE PRECIP PERSIST INTO
THE OVERNIGHT/ BETWEEN 06Z AND 09Z FOR THE COLUMN TO COOL ENOUGH TO
SUPPORT ALL SNOW. THIS WILL BE ALONG THE LEADING EDGE OF DRIER MID
LEVEL AIR AND THUS END OF PRECIP. SO THE CURRENT FORECAST SUGGESTING
A MINIMAL AMOUNT OF SNOW ACCUMS OVERNIGHT ACROSS THE SAGINAW VALLEY
AND THUMB CONTINUES TO LOOK REASONABLE.

&&

.LONG TERM...WEDNESDAY THROUGH MONDAY

THE WELL DISCUSSED STACKED LOW PRESSURE SYSTEM WILL BE EXITING TO
THE EAST ON WEDNESDAY BUT A STRONG NORTHERN STREAM PV ANOMALY WILL
BE SHEARING OUT AS IT DIGS DOWN AND THE AROUND THE BACKSIDE OF THE
TROUGH THROUGH SOUTHERN MI. IN ADDITION...LINGERING TROUGH AXIS WILL
BE DRAPED ACROSS CENTRAL/NORTHERN MI BEHIND THE EXITING LOW. A MID
LEVEL COLD POOL...APPROACHING -27C AT 500MB...WILL ACCOMPANY THE VORT
MAX ACROSS SOUTHERN MI DURING THE EVENING HOURS BEHIND AN ARCTIC
FRONT. THE FRONT WILL LOWER FROM ABOUT 500MB OVER MBS TO CLOSER TO
700MB BY THE TIME IT EXITS THE EASTERN CWA...WHILE LOSING SOME
FORCING. THIS SHOULD NOT AMOUNT TO MUCH AT THE SFC BECAUSE MOISTURE
WILL BE LACKING OVER THE AREA WITH DRY AIR BUILDING IN QUICKLY FROM
THE TOP DOWN THROUGH THE PROFILE AS RIDGING BUILDS IN BEHIND THE
UPPER LOW. PWATS WILL BE AROUND 0.4 INCHES WITH SPECIFIC HUMIDITIES
COMING IN MAINLY AROUND 1 G/KG AND ALL BELOW THE INVERSION CENTERED
AROUND 850MB. THIS WILL ALL LEAD TO ANOTHER DAY WITH AMPLE LL CLOUD
COVER AND MUCH COOLER HIGH TEMPS AS WESTERLY WINDS RAMP UP IN THE
WAKE OF THE SFC COLD FRONT. WITH LITTLE MOISTURE TO WORK WITH...DO
NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOWFALL ALTHOUGH
FLURRIES OR LIGHT SNOW SHOWERS WILL BE PREVALENT THROUGH THE EVENING
WITH SOME DEGREE OF LAKE EFFECT KICKING IN. THE WILL BE MORE
CONFINED ACROSS THE FAR NORTH ALTHOUGH SOME HIRES MODELS ARE TRYING
TO SHOW A BAND DEVELOPING LATER IN THE DAY BETWEEN M59 AND I94. THIS
REMAINS TO BE SEEN WITH THE POOR CONVERGENT SIGNATURE SO WILL NOT
HIGHLIGHT ANY POTENTIAL FOR ACCUMS ACROSS THE AREA. THE ACTIVITY
WILL SHUT OFF OVERNIGHT WEDNESDAY EXCEPT FOR THE EASTERN THUMB WHERE
THE MAIN LAKE HURON BAND LOOKS TO BRUSH THOSE COUNTIES...WHICH WILL
LINGER INTO THURSDAY. GUSTY W/NW FLOW WILL PERSIST WEDNESDAY INTO
THURSDAY. OVERALL THE SNOW THREAT IS LOW AND TEMPERATURES WILL
RETURN TO NEAR NORMAL FOR MID DECEMBER WITH HIGHS IN THE LOW/MID
30S AND LOWS IN THE MID 20S.

SOUTHERN STREAM JET WILL SPARK LOW PRESSURE IN THE LOWER MISSISSIPPI
VALLEY FRIDAY THAT SHOULD REMAIN WELL SOUTH OF MICHIGAN AS IT MOVES
NORTHEAST THROUGH THE TENNESSEE VALLEY. AN UPPER LEVEL TROUGH WILL
GENERALLY KEEP COOL TEMPS IN THE FORECAST...BUT SURFACE HIGH
PRESSURE WILL ENSURE DRY CONDITIONS. THIS PATTERN WILL REMAIN IN
PLACE THROUGH THE WEEKEND. 170 KT JET AND MOISTURE COMING ONSHORE IN
THE PACIFIC EARLY NEXT WEEK MAY EVENTUALLY REACH MICHIGAN TOWARD DAY
7.

&&

.MARINE...

THE CENTER OF THE SFC LOW IS NOW OVER THE EASTERN GREAT LAKES AND
WILL CONTINUE ITS PUSH EAST THROUGH THE OVERNIGHT. THIS WILL OPEN
THE DOOR FOR STRONG WESTERLY FLOW WITH COLD AIR ADVECTION ACROSS THE
LAKES. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO THE STRONGEST
FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT THAT LEVEL. IT
SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS DOWN THOUGH
WITH SUSTAINED FLOW PUSHING 20 KNOTS. HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE ZONES STARTING WITH LAKE ERIE THIS
EVENING...FOLLOWED BY THE LAKE HURON ZONES AND LAKE ST CLAIR LATE
TONIGHT FOR THESE ELEVATED WINDS. WAVES WILL ALSO REACH CRITERIA IN
SOME OF THE LAKE HURON ZONES BUT OFFSHORE FLOW WILL KEEP WAVE
HEIGHTS DOWN SOMEWHAT ALONG WITH SOME ICE COVER SHOWING UP IN INNER
SAGINAW BAY. WINDS WILL DECREASE BELOW CRITERIA WEDNESDAY AFTERNOON
BUT WILL STAY ELEVATED THROUGH WEDNESDAY NIGHT AS THE VEER TO THE
NORTHWEST.

&&

.AVIATION...ISSUED 1206 PM EST TUE DEC 16 2014

//DISCUSSION...

ALTHOUGH THERE HAS BEEN AN IMPROVEMENT TO THE VISIBILITIES OVER THE
LAST COUPLE OF HOURS...CEILINGS WILL REMAIN LOW UNTIL THE PASSAGE OF
A SURFACE LOW AND OCCLUDED FRONT. THIS FRONT /NOW LIFTING NORTH OF
DETROIT/ WILL NOT EXIT MBS UNTIL ROUGHLY 00Z THIS EVENING. THERE
WILL BE A SLOW RISE IN CEILINGS WITH THE PASSAGE OF THE OCCLUDED
FRONT...ALSO MARKED BY WIND SHIFT TO THE SOUTHWEST. A MORE STEADY
RISE IN CEILINGS WILL OCCUR AFTER 02 OR 03Z WITH AN INITIAL SURGE IN
COLDER LOW LEVEL AIR. THIS ONSET OF COLDER LOW LEVEL AIR WILL ALSO
BE MARKED BY AN INCREASE IN THE WSW WINDS...EXPECTED TO GUST OVER 20
KNOTS AS THE DEPTH OF THE COLD AIR INCREASES TONIGHT.

FOR DTW...THERE HAS BEEN A SUBSTANTIAL RISE IN CEILING HEIGHTS IN
THE WARM SECTOR OVER NW OHIO. THE EXPECTATION IS THAT THE OCCLUSION
OF THE SURFACE FRONT WILL KEEP THESE HIGHER CEILINGS SOUTH AND EAST
OF METRO THIS AFTERNOON...ALTHOUGH A BRIEF INTERVAL OF BASES LIFTING
ABOVE 1K FT LOOKS POSSIBLE. THE EXTENSIVE AMOUNT OF IFR CLOUDS TO
THE SOUTHWEST OF METRO SUPPORTS HOLDING A PREDOMINATE IFR CEILING
THROUGH THE DURATION OF THE AFTERNOON.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THIS AFTERNOON AND
  TONIGHT.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS ALL RAIN.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LHZ421-422-
     441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST WEDNESDAY
     FOR LEZ444.

&&

$$

SHORT TERM...SC
LONG TERM....DRK/MM
MARINE.......DRK
AVIATION.....SC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 162052
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
352 PM EST TUE DEC 16 2014

.SHORT TERM... THIS EVENING AND TONIGHT

THE WIDESPREAD RAIN WHICH HAS AFFECTED MUCH OF THE SRN AND ERN
PORTIONS OF SE MI TODAY WILL CONTINUE TO SLOWLY ROTATE EAST OF METRO
DETROIT AND PORT HURON DURING THE REMAINDER OF THE AFTERNOON.
ADDITIONAL SHOWERS NOW ROTATING INTO THE AREA FROM THE WEST ARE
OCCURRING WITHIN ENHANCED LARGE SCALE ASCENT AHEAD OF A SHORT WAVE
SLIDING ACROSS CENTRAL LAKE MI. THERE ALSO APPEARS TO BE SOME
INTERACTION WITH THE UPPER TROUGH OVER THE ERN GREAT LAKES...LEADING
TO INCREASING MID LEVEL DEFORMATION ACROSS SE MI. THE SHORT WAVE IS
FORECAST TO DAMPEN AS IT ROTATES INTO SE MI THIS EVENING...WHILE THE
LONGER WAVELENGTH TROUGH LIFTS NORTH. THE UPPER LOW NOW OVER
MINNESOTA WILL BE THE FEATURE WHICH DRIVES THESE FORCING MECHANISM
NORTH AS IT ADVANCES ACROSS THE WRN GREAT LAKES TONIGHT. THE NET
RESULT WILL BE A SHIFTING OF THE BETTER LARGER SCALE FORCING AND
SHOWER COVERAGE TOWARD THE NORTHERN HALF OF THE FORECAST AREA DURING
THE COURSE OF THE EVENING.

THE SURFACE LOW AND ASSOCIATED OCCLUDED FRONT /LOCATED OVER THE
THUMB REGION AS OF 19Z/ WILL BE FORCED INTO THE SRN BASIN OF LAKE
HURON THIS EVENING...THEN NORTHEAST TO ONTARIO OVERNIGHT. THE 19Z
SURFACE OBSERVATIONS DO SHOW THE COLD AIR LAGGING WELL BEHIND THE
SURFACE LOW...WITH A SECONDARY COLD FRONT STILL ALONG THE WRN SHORE
OF LOWER MI. THIS FRONT WILL NOT PUSH INTO SE MI UNTIL MUCH LATER
THIS EVENING /03Z TO 06Z/. SOME SEMBLANCE OF AN ISSALOBARIC
COMPONENT ALONG THE FRONT AND ARRIVAL OF COLD AIR WILL LEAD TO
INCREASING WINDS. LOW LEVEL COLD AIR ADVECTION THROUGH THE NIGHT
WILL ALSO DEEPEN THE MIXED LAYER AND WILL BE SUPPORTIVE OF SOME
GUSTS UP TO 30 MPH DURING THE OVERNIGHT. AS TEMPS COOL
OVERNIGHT...THE COLUMN WILL BECOME COLD ENOUGH TO SUPPORT ALL SNOW.
A LINGERING THERMAL TROUGH ACROSS THE TRI CITIES AND THUMB SUGGEST
IT WILL TAKE THIS REGION /ALSO THE AREA TO SEE PRECIP PERSIST INTO
THE OVERNIGHT/ BETWEEN 06Z AND 09Z FOR THE COLUMN TO COOL ENOUGH TO
SUPPORT ALL SNOW. THIS WILL BE ALONG THE LEADING EDGE OF DRIER MID
LEVEL AIR AND THUS END OF PRECIP. SO THE CURRENT FORECAST SUGGESTING
A MINIMAL AMOUNT OF SNOW ACCUMS OVERNIGHT ACROSS THE SAGINAW VALLEY
AND THUMB CONTINUES TO LOOK REASONABLE.

&&

.LONG TERM...WEDNESDAY THROUGH MONDAY

THE WELL DISCUSSED STACKED LOW PRESSURE SYSTEM WILL BE EXITING TO
THE EAST ON WEDNESDAY BUT A STRONG NORTHERN STREAM PV ANOMALY WILL
BE SHEARING OUT AS IT DIGS DOWN AND THE AROUND THE BACKSIDE OF THE
TROUGH THROUGH SOUTHERN MI. IN ADDITION...LINGERING TROUGH AXIS WILL
BE DRAPED ACROSS CENTRAL/NORTHERN MI BEHIND THE EXITING LOW. A MID
LEVEL COLD POOL...APPROACHING -27C AT 500MB...WILL ACCOMPANY THE VORT
MAX ACROSS SOUTHERN MI DURING THE EVENING HOURS BEHIND AN ARCTIC
FRONT. THE FRONT WILL LOWER FROM ABOUT 500MB OVER MBS TO CLOSER TO
700MB BY THE TIME IT EXITS THE EASTERN CWA...WHILE LOSING SOME
FORCING. THIS SHOULD NOT AMOUNT TO MUCH AT THE SFC BECAUSE MOISTURE
WILL BE LACKING OVER THE AREA WITH DRY AIR BUILDING IN QUICKLY FROM
THE TOP DOWN THROUGH THE PROFILE AS RIDGING BUILDS IN BEHIND THE
UPPER LOW. PWATS WILL BE AROUND 0.4 INCHES WITH SPECIFIC HUMIDITIES
COMING IN MAINLY AROUND 1 G/KG AND ALL BELOW THE INVERSION CENTERED
AROUND 850MB. THIS WILL ALL LEAD TO ANOTHER DAY WITH AMPLE LL CLOUD
COVER AND MUCH COOLER HIGH TEMPS AS WESTERLY WINDS RAMP UP IN THE
WAKE OF THE SFC COLD FRONT. WITH LITTLE MOISTURE TO WORK WITH...DO
NOT EXPECT MUCH IN THE WAY OF ACCUMULATING SNOWFALL ALTHOUGH
FLURRIES OR LIGHT SNOW SHOWERS WILL BE PREVALENT THROUGH THE EVENING
WITH SOME DEGREE OF LAKE EFFECT KICKING IN. THE WILL BE MORE
CONFINED ACROSS THE FAR NORTH ALTHOUGH SOME HIRES MODELS ARE TRYING
TO SHOW A BAND DEVELOPING LATER IN THE DAY BETWEEN M59 AND I94. THIS
REMAINS TO BE SEEN WITH THE POOR CONVERGENT SIGNATURE SO WILL NOT
HIGHLIGHT ANY POTENTIAL FOR ACCUMS ACROSS THE AREA. THE ACTIVITY
WILL SHUT OFF OVERNIGHT WEDNESDAY EXCEPT FOR THE EASTERN THUMB WHERE
THE MAIN LAKE HURON BAND LOOKS TO BRUSH THOSE COUNTIES...WHICH WILL
LINGER INTO THURSDAY. GUSTY W/NW FLOW WILL PERSIST WEDNESDAY INTO
THURSDAY. OVERALL THE SNOW THREAT IS LOW AND TEMPERATURES WILL
RETURN TO NEAR NORMAL FOR MID DECEMBER WITH HIGHS IN THE LOW/MID
30S AND LOWS IN THE MID 20S.

SOUTHERN STREAM JET WILL SPARK LOW PRESSURE IN THE LOWER MISSISSIPPI
VALLEY FRIDAY THAT SHOULD REMAIN WELL SOUTH OF MICHIGAN AS IT MOVES
NORTHEAST THROUGH THE TENNESSEE VALLEY. AN UPPER LEVEL TROUGH WILL
GENERALLY KEEP COOL TEMPS IN THE FORECAST...BUT SURFACE HIGH
PRESSURE WILL ENSURE DRY CONDITIONS. THIS PATTERN WILL REMAIN IN
PLACE THROUGH THE WEEKEND. 170 KT JET AND MOISTURE COMING ONSHORE IN
THE PACIFIC EARLY NEXT WEEK MAY EVENTUALLY REACH MICHIGAN TOWARD DAY
7.

&&

.MARINE...

THE CENTER OF THE SFC LOW IS NOW OVER THE EASTERN GREAT LAKES AND
WILL CONTINUE ITS PUSH EAST THROUGH THE OVERNIGHT. THIS WILL OPEN
THE DOOR FOR STRONG WESTERLY FLOW WITH COLD AIR ADVECTION ACROSS THE
LAKES. MIXING DEPTHS UP TO AROUND 900MB WILL TAP INTO THE STRONGEST
FLOW WHICH IS ONLY FORECAST TO BE AROUND 35 KNOTS AT THAT LEVEL. IT
SHOULD NOT TAKE TOO MUCH TO BRING SOME HIGHER GUSTS DOWN THOUGH
WITH SUSTAINED FLOW PUSHING 20 KNOTS. HAVE ISSUED SMALL CRAFT
ADVISORIES FOR ALL NEARSHORE ZONES STARTING WITH LAKE ERIE THIS
EVENING...FOLLOWED BY THE LAKE HURON ZONES AND LAKE ST CLAIR LATE
TONIGHT FOR THESE ELEVATED WINDS. WAVES WILL ALSO REACH CRITERIA IN
SOME OF THE LAKE HURON ZONES BUT OFFSHORE FLOW WILL KEEP WAVE
HEIGHTS DOWN SOMEWHAT ALONG WITH SOME ICE COVER SHOWING UP IN INNER
SAGINAW BAY. WINDS WILL DECREASE BELOW CRITERIA WEDNESDAY AFTERNOON
BUT WILL STAY ELEVATED THROUGH WEDNESDAY NIGHT AS THE VEER TO THE
NORTHWEST.

&&

.AVIATION...ISSUED 1206 PM EST TUE DEC 16 2014

//DISCUSSION...

ALTHOUGH THERE HAS BEEN AN IMPROVEMENT TO THE VISIBILITIES OVER THE
LAST COUPLE OF HOURS...CEILINGS WILL REMAIN LOW UNTIL THE PASSAGE OF
A SURFACE LOW AND OCCLUDED FRONT. THIS FRONT /NOW LIFTING NORTH OF
DETROIT/ WILL NOT EXIT MBS UNTIL ROUGHLY 00Z THIS EVENING. THERE
WILL BE A SLOW RISE IN CEILINGS WITH THE PASSAGE OF THE OCCLUDED
FRONT...ALSO MARKED BY WIND SHIFT TO THE SOUTHWEST. A MORE STEADY
RISE IN CEILINGS WILL OCCUR AFTER 02 OR 03Z WITH AN INITIAL SURGE IN
COLDER LOW LEVEL AIR. THIS ONSET OF COLDER LOW LEVEL AIR WILL ALSO
BE MARKED BY AN INCREASE IN THE WSW WINDS...EXPECTED TO GUST OVER 20
KNOTS AS THE DEPTH OF THE COLD AIR INCREASES TONIGHT.

FOR DTW...THERE HAS BEEN A SUBSTANTIAL RISE IN CEILING HEIGHTS IN
THE WARM SECTOR OVER NW OHIO. THE EXPECTATION IS THAT THE OCCLUSION
OF THE SURFACE FRONT WILL KEEP THESE HIGHER CEILINGS SOUTH AND EAST
OF METRO THIS AFTERNOON...ALTHOUGH A BRIEF INTERVAL OF BASES LIFTING
ABOVE 1K FT LOOKS POSSIBLE. THE EXTENSIVE AMOUNT OF IFR CLOUDS TO
THE SOUTHWEST OF METRO SUPPORTS HOLDING A PREDOMINATE IFR CEILING
THROUGH THE DURATION OF THE AFTERNOON.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THIS AFTERNOON AND
  TONIGHT.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS ALL RAIN.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LHZ421-422-
     441>443.

LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 4 AM TO 4 PM EST WEDNESDAY FOR LCZ460.

MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST WEDNESDAY
     FOR LEZ444.

&&

$$

SHORT TERM...SC
LONG TERM....DRK/MM
MARINE.......DRK
AVIATION.....SC


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 161706
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1206 PM EST TUE DEC 16 2014


.AVIATION...

//DISCUSSION...

ALTHOUGH THERE HAS BEEN AN IMPROVEMENT TO THE VISIBILITIES OVER THE
LAST COUPLE OF HOURS...CEILINGS WILL REMAIN LOW UNTIL THE PASSAGE OF
A SURFACE LOW AND OCCLUDED FRONT. THIS FRONT /NOW LIFTING NORTH OF
DETROIT/ WILL NOT EXIT MBS UNTIL ROUGHLY 00Z THIS EVENING. THERE
WILL BE A SLOW RISE IN CEILINGS WITH THE PASSAGE OF THE OCCLUDED
FRONT...ALSO MARKED BY WIND SHIFT TO THE SOUTHWEST. A MORE STEADY
RISE IN CEILINGS WILL OCCUR AFTER 02 OR 03Z WITH AN INITIAL SURGE IN
COLDER LOW LEVEL AIR. THIS ONSET OF COLDER LOW LEVEL AIR WILL ALSO
BE MARKED BY AN INCREASE IN THE WSW WINDS...EXPECTED TO GUST OVER 20
KNOTS AS THE DEPTH OF THE COLD AIR INCREASES TONIGHT.

FOR DTW...THERE HAS BEEN A SUBSTANTIAL RISE IN CEILING HEIGHTS IN
THE WARM SECTOR OVER NW OHIO. THE EXPECTATION IS THAT THE OCCLUSION
OF THE SURFACE FRONT WILL KEEP THESE HIGHER CEILINGS SOUTH AND EAST
OF METRO THIS AFTERNOON...ALTHOUGH A BRIEF INTERVAL OF BASES LIFTING
ABOVE 1K FT LOOKS POSSIBLE. THE EXTENSIVE AMOUNT OF IFR CLOUDS TO
THE SOUTHWEST OF METRO SUPPORTS HOLDING A PREDOMINATE IFR CEILING
THROUGH THE DURATION OF THE AFTERNOON.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THIS AFTERNOON AND
  TONIGHT.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS ALL RAIN.

&&

.PREV DISCUSSION...ISSUED 1014 AM EST TUE DEC 16 2014

UPDATE...

THE REGION OF RAIN ASSOCIATED WITH PUSH OF ENHANCED ISENTROPIC
ASCENT WILL CONTINUE TO PUSH NORTHWARD ACROSS THE FORECAST AREA
DURING THE REMAINDER OF THE MORNING AND WELL INTO THE AFTERNOON.
WHILE THE COVERAGE OF RAIN WILL DECREASE ACROSS METRO DETROIT AND
POINTS SOUTH DURING THE AFTERNOON AS THE LARGE SCALE FORCING
SHIFTS TO THE NORTH...RESIDUAL DEEP LAYER MOISTURE AND STEEP MID
LEVEL LAPSE RATES WILL SUPPORT SCT TO NMRS SHOWERS THROUGH THE
AFTERNOON /VERY MUCH IN LINE WITH THE CURRENT FCST/.

AMPLE LOW LEVEL MOISTURE ADVECTION ALONG A SURFACE OCCLUDED FRONT
HAS LED TO A SUBSTANTIAL AMOUNT OF FOG ACROSS SRN MI. THE SURFACE
OCCLUDED FRONT WILL LIFT NORTH OF METRO DETROIT EARLY THIS
AFTERNOON. THIS WILL OPEN THE DOOR FOR A LITTLE STRONGER SW WINDS
AND A MODEST RISE IN SFC TEMPS FROM ROUGHLY THE M 69 CORRIDOR
SOUTH. THESE FACTORS SUGGEST VISIBILITY IMPROVEMENT DURING THE
EARLY AFTERNOON. THE SFC OCCLUSION WILL TAKE LONGER TO LIFT ACROSS
THE NORTHERN HALF OF THE FORECAST AREA...LIKELY NOT PUSHING ACROSS
THE TRI CITIES AND NRN THUMB UNTIL LATE AFTERNOON. THIS WILL
SUPPORT CONTINUING THE MENTION OF FOG THROUGH THE AFTERNOON
ACROSS THE NRN HALF OF THE FORECAST AREA /GENERALLY ALONG AND
NORTH OF I-69/.

SFC OBSERVATIONS SUGGEST THERE WILL BE SOME SLIGHT RISE IN TEMPS
ACROSS METRO DETROIT THIS AFTERNOON. FARTHER NORTH HOWEVER...TEMPS
SHOULD REMAIN FAIRLY STEADY WITH THE SFC LOW AND OCCLUSION
OVERHEAD WELL INTO THE AFTERNOON. SO AN UPDATE WILL ALSO BE
ISSUED TO REFLECT THESE EXPECTED TEMP TRENDS.

PREV DISCUSSION...ISSUED 353 AM EST TUE DEC 16 2014

SHORT TERM... TODAY AND TONIGHT

LOW PRESSURE SLIDING THROUGH LOWER MICHIGAN WILL MAINTAIN DAMP BUT
MILD CONDITIONS ACROSS THE AREA TODAY. AFTER THE FIRST WAVE OF RAIN
EARLIER IN THE NIGHT...DRIZZLE AND FOG WILL BE ONGOING UNTIL THE
NEXT ROUND OF SHOWERS ARRIVES DURING THE DAYLIGHT HOURS OF THE
MORNING. RAIN WILL THEN CONTINUE OFF AND ON THROUGHOUT THE DAY AS
TEMPERATURES REMAIN STEADY OR RISE SLIGHTLY FROM THE MID 40S TO
AROUND 50 DURING THE AFTERNOON. THE LOW WILL THEN MOVE INTO ONTARIO
TONIGHT AND PULL COLDER AIR INTO THE REGION ON INCREASING WESTERLY
WIND. GUSTS INCREASING TO NEAR 30 MPH LATE IN THE NIGHT WILL HELP
CARRY MIN TEMPERATURES BELOW THE FREEZING MARK BY SUNRISE WEDNESDAY.
A MIX OF RAIN AND SNOW CHANGING TO SNOW WILL BE POSSIBLE ON THE
TRAILING EDGE OF THE PRECIPITATION PATTERN OVER THE SAGINAW VALLEY
AND NORTHERN THUMB BUT WITH LITTLE TO NO ACCUMULATION EXPECTED.

EARLY MORNING SATELLITE IMAGERY SHOWS THE MID LEVEL DRY SLOT
ASSOCIATED WITH THE UPPER LOW SLIDING OVER LOWER MICHIGAN AT PRESS
TIME. THE MID LEVEL DRY AIR WILL LIMIT PRECIPITATION TO DRIZZLE IN
DEEP BOUNDARY LAYER MOISTURE AHEAD OF AND WITHIN THE SURFACE
OCCLUDED FRONT. DRIZZLE AND FOG WILL CONTINUE WITHIN THE OCCLUSION
AS IT LEADS THE SURFACE LOW THROUGH LOWER MICHIGAN WHILE COVERAGE OF
SHOWERS INCREASES AGAIN FROM ABOUT MID MORNING THROUGH THE REST OF
THE DAY. EARLY MORNING RADAR COMPOSITE AND MODEL FIELDS INDICATE
SHOWERS RELOADING OVER INDIANA AS A NEW ROUND OF ISENTROPIC ASCENT
INTERACTS WITH DYNAMIC FORCING OF THE UPPER LOW. THE ASSOCIATED COLD
POOL ALOFT...NEAR -25C AT 500 MB...WILL ALSO CONTRIBUTE ELEVATED
INSTABILITY TO AID IN EXPANSION OF THE RAIN PATTERN. COVERAGE MAY
NOT BE SOLID THROUGHOUT THE DAY BUT ENTRY LEVEL CATEGORICAL POPS ARE
A GOOD FIT AS THE UPPER LOW OPENS OVER LOWER MICHIGAN AND SETS UP A
WELL ORGANIZED BAND OF DEFORMATION TO ENHANCE THE OCCLUSION.

THE NORTHERN STREAM UPPER WAVE OVER CENTRAL CANADA TODAY WILL MOVE
INTO THE UPPER MIDWEST TONIGHT AND KICK THE GREAT LAKES SYSTEM OUT
OF THE AREA. DRY AIR BETWEEN THE TWO SYSTEMS WILL BRING AN END TO
PRECIPITATION FROM SW TO NE OVER LOWER MICHIGAN DURING THE OVERNIGHT
HOURS. THE EXCEPTION WILL BE THE SAGINAW VALLEY AND NORTHERN THUMB
NEAR THE SOUTH FLANK OF MID LEVEL DEFORMATION STRUNG OUT BETWEEN THE
TWO UPPER WAVES. A LIGHT MIX OF RAIN AND SNOW IS LIKELY THERE AS
COLDER AIR INVADES THE LOW LEVELS. MODEL PROJECTIONS OF LOW LEVEL
THICKNESS AND FORECAST SOUNDINGS SUGGEST ALL RAIN TO START THE NIGHT
THEN BECOMING MIXED WITH AND CHANGING TO SNOW AROUND AND AFTER
MIDNIGHT. AT THIS POINT...THE SLIGHTLY LATER TIMING ON THIS
TRANSITION COMBINED WITH A SLOW BUT STEADY DOWNWARD DRIFT IN SURFACE
TEMPERATURES WILL LIMIT ANY ACCUMULATION TO POSSIBLY A SLUSHY
COATING BY SUNRISE WEDNESDAY. WIND GUSTS WILL BE DRIVEN BY THE LOW
LEVEL COLD ADVECTION AND MIXED LAYER DEEPENING TO ABOUT 900 MB AFTER
MIDNIGHT. PEAK WIND GUSTS NEAR 30 MPH SUGGESTED BY MODEL SOUNDINGS
APPEARS REASONABLE GIVEN THE SURFACE LOW IS FILLING WITH TIME AS IT
EXITS INTO ONTARIO.

LONG TERM...WEDNESDAY THROUGH MONDAY

A CLOSED 500 MB LOW WILL TRACK EAST SOUTHEAST THROUGH THE NORTHERN
GREAT LAKES ON WEDNESDAY WITH A STRONG PV ANOMALY MAKING ITS WAY
THROUGH SOUTHERN LOWER MICHIGAN.  THIS WILL BE OCCURRING AS THE
STRONGEST 850 MB COLD AIR ADVECTION TAKES PLACE WITH TEMPERATURES
PLUNGING TO -10 TO -12 CELSIUS.  THE STRONG LOW AND COLD AIR
ADVECTION WILL CAUSE WESTERLY WINDS TO INCREASE TO 20 TO 30 MPH ON
WEDNESDAY. IN ADDITION SOME LIGHT SNOW AND FLURRIES WILL BE POSSIBLE
WITH THE LIFT AND COLD AIR IN PLACE.  MOISTURE WILL BE THE LIMITING
FACTOR ON WEDNESDAY AS MODEL SOUNDINGS SHOW A FAIRLY SHALLOW LAYER
OF MOISTURE IN PLACE ACROSS MOST OF THE CWA. THE DEEPEST MOISTURE
WILL BE ACROSS THE SAGINAW VALLEY AND THUMB REGION...WHERE SNOWFALL
AMOUNTS ARE EXPECTED TO BE HALF OF AN INCH OR LESS. ACROSS THE
SOUTHERN CWA JUST SOME LAKE MICHIGAN FLURRIES OR LIGHT SNOW IS
EXPECTED AS THE FLOW BACKS TO THE WEST NORTHWEST.

RIDGING THEN SLOWLY WORKS ITS WAY ACROSS THE WESTERN GREAT LAKES
WEDNESDAY NIGHT AND THURSDAY...PUSHING ANY CHANCE OF SNOW OFF TO
EAST AS WINDS TURN TO A MORE NORTHWESTERLY DIRECTION.  UNDER THIS
SETUP THE EXTREME EASTERN THUMB MAY GET BRUSHED WITH SOME FLURRY
ACTIVITY...HOWEVER WINDS APPEAR TO BE TOO WEST TO MAKE MUCH OF AN
IMPACT ACROSS THIS AREA. THE PATTERN THEN GOES FAIRLY DRY FOR THE
REMAINDER OF THE FORECAST AS THIS RIDGE BUILDS IN ACROSS THE GREAT
LAKES REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.  THE MAIN
SYSTEM OF CONCERN DURING THIS WEEKEND IS A SYSTEM EMERGING OUT OF
THE SOUTHERN PLAINS AND TRACKING THROUGH THE SOUTHEASTERN CONUS AND
EVENTUALLY OFF THE COAST OF NEW ENGLAND. HOWEVER THE AFOREMENTIONED
HIGH PRESSURE IN PLACE IS EXPECTED TO KEEP THIS SYSTEM WELL TO OUR
SOUTH AS IT FEEDS DRY AIR IN FROM CANADA. ALTHOUGH THE PATTERN WILL
BE DECIDEDLY COLDER THAN THE LAST FEW DAYS...TEMPERATURES WILL
ACTUALLY BE FAIRLY CLOSE TO NORMAL DURING THIS PERIOD AS THE COLDEST
AIR STAYS LOCKED IN ACROSS THE ARCTIC.

MARINE...

AS AN OCCLUDED SURFACE LOW MOVES INTO THE GREAT LAKES REGION...A
WARM FRONT WILL LIFT NORTH THROUGH LAKE HURON AND USHER IN WARM AND
MOIST AIR. THE SURFACE LOW IS EXPECTED TO WEAKEN AS IT TRACKS ACROSS
THE REGION...BUT THERE WILL STILL BE A DECENT AREA OF COLD AIR
ADVECTION ON THE SOUTHWEST FLANK OF THE LOW. THE TIMING OF THIS
FEATURE WILL HELP INCREASE WIND SPEEDS TONIGHT AND WEDNESDAY. MODEL
SOUNDINGS SUGGEST THE PEAK WINDS WILL BE AT THE 925 MB/2000 FT
LEVEL. AT THESE HEIGHTS...WINDS COULD REACH UP TO 35 KT. PEAK MIXING
WEDNESDAY AFTERNOON MAY ALLOW FOR BRIEF GUSTS TO GALES...BUT
WIDESPREAD AND PERSISTENT GUSTS AT THAT SPEED ARE NOT LIKELY. COMMON
WIND VECTORS WILL BE 25-30KT FROM THE WEST ON WEDNESDAY. WINDS AND
WAVES WILL DROP OFF NOTICEABLY ON THURSDAY AS HIGH PRESSURE BUILDS
IN ACROSS THE GREAT LAKES. WAVES DO NOT LOOK TO REACH SMALL CRAFT
CRITERIA ACROSS PORTIONS OF THE LAKE HURON NEARSHORE AND OUTER
SAGINAW BAY UNTIL WEDNESDAY...THEREFORE WILL HOLD OFF ON ISSUING
ANY HEADLINES UNTIL LATER FORECASTS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....SC
UPDATE.......SC
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 161706
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1206 PM EST TUE DEC 16 2014


.AVIATION...

//DISCUSSION...

ALTHOUGH THERE HAS BEEN AN IMPROVEMENT TO THE VISIBILITIES OVER THE
LAST COUPLE OF HOURS...CEILINGS WILL REMAIN LOW UNTIL THE PASSAGE OF
A SURFACE LOW AND OCCLUDED FRONT. THIS FRONT /NOW LIFTING NORTH OF
DETROIT/ WILL NOT EXIT MBS UNTIL ROUGHLY 00Z THIS EVENING. THERE
WILL BE A SLOW RISE IN CEILINGS WITH THE PASSAGE OF THE OCCLUDED
FRONT...ALSO MARKED BY WIND SHIFT TO THE SOUTHWEST. A MORE STEADY
RISE IN CEILINGS WILL OCCUR AFTER 02 OR 03Z WITH AN INITIAL SURGE IN
COLDER LOW LEVEL AIR. THIS ONSET OF COLDER LOW LEVEL AIR WILL ALSO
BE MARKED BY AN INCREASE IN THE WSW WINDS...EXPECTED TO GUST OVER 20
KNOTS AS THE DEPTH OF THE COLD AIR INCREASES TONIGHT.

FOR DTW...THERE HAS BEEN A SUBSTANTIAL RISE IN CEILING HEIGHTS IN
THE WARM SECTOR OVER NW OHIO. THE EXPECTATION IS THAT THE OCCLUSION
OF THE SURFACE FRONT WILL KEEP THESE HIGHER CEILINGS SOUTH AND EAST
OF METRO THIS AFTERNOON...ALTHOUGH A BRIEF INTERVAL OF BASES LIFTING
ABOVE 1K FT LOOKS POSSIBLE. THE EXTENSIVE AMOUNT OF IFR CLOUDS TO
THE SOUTHWEST OF METRO SUPPORTS HOLDING A PREDOMINATE IFR CEILING
THROUGH THE DURATION OF THE AFTERNOON.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET THIS AFTERNOON AND
  TONIGHT.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS ALL RAIN.

&&

.PREV DISCUSSION...ISSUED 1014 AM EST TUE DEC 16 2014

UPDATE...

THE REGION OF RAIN ASSOCIATED WITH PUSH OF ENHANCED ISENTROPIC
ASCENT WILL CONTINUE TO PUSH NORTHWARD ACROSS THE FORECAST AREA
DURING THE REMAINDER OF THE MORNING AND WELL INTO THE AFTERNOON.
WHILE THE COVERAGE OF RAIN WILL DECREASE ACROSS METRO DETROIT AND
POINTS SOUTH DURING THE AFTERNOON AS THE LARGE SCALE FORCING
SHIFTS TO THE NORTH...RESIDUAL DEEP LAYER MOISTURE AND STEEP MID
LEVEL LAPSE RATES WILL SUPPORT SCT TO NMRS SHOWERS THROUGH THE
AFTERNOON /VERY MUCH IN LINE WITH THE CURRENT FCST/.

AMPLE LOW LEVEL MOISTURE ADVECTION ALONG A SURFACE OCCLUDED FRONT
HAS LED TO A SUBSTANTIAL AMOUNT OF FOG ACROSS SRN MI. THE SURFACE
OCCLUDED FRONT WILL LIFT NORTH OF METRO DETROIT EARLY THIS
AFTERNOON. THIS WILL OPEN THE DOOR FOR A LITTLE STRONGER SW WINDS
AND A MODEST RISE IN SFC TEMPS FROM ROUGHLY THE M 69 CORRIDOR
SOUTH. THESE FACTORS SUGGEST VISIBILITY IMPROVEMENT DURING THE
EARLY AFTERNOON. THE SFC OCCLUSION WILL TAKE LONGER TO LIFT ACROSS
THE NORTHERN HALF OF THE FORECAST AREA...LIKELY NOT PUSHING ACROSS
THE TRI CITIES AND NRN THUMB UNTIL LATE AFTERNOON. THIS WILL
SUPPORT CONTINUING THE MENTION OF FOG THROUGH THE AFTERNOON
ACROSS THE NRN HALF OF THE FORECAST AREA /GENERALLY ALONG AND
NORTH OF I-69/.

SFC OBSERVATIONS SUGGEST THERE WILL BE SOME SLIGHT RISE IN TEMPS
ACROSS METRO DETROIT THIS AFTERNOON. FARTHER NORTH HOWEVER...TEMPS
SHOULD REMAIN FAIRLY STEADY WITH THE SFC LOW AND OCCLUSION
OVERHEAD WELL INTO THE AFTERNOON. SO AN UPDATE WILL ALSO BE
ISSUED TO REFLECT THESE EXPECTED TEMP TRENDS.

PREV DISCUSSION...ISSUED 353 AM EST TUE DEC 16 2014

SHORT TERM... TODAY AND TONIGHT

LOW PRESSURE SLIDING THROUGH LOWER MICHIGAN WILL MAINTAIN DAMP BUT
MILD CONDITIONS ACROSS THE AREA TODAY. AFTER THE FIRST WAVE OF RAIN
EARLIER IN THE NIGHT...DRIZZLE AND FOG WILL BE ONGOING UNTIL THE
NEXT ROUND OF SHOWERS ARRIVES DURING THE DAYLIGHT HOURS OF THE
MORNING. RAIN WILL THEN CONTINUE OFF AND ON THROUGHOUT THE DAY AS
TEMPERATURES REMAIN STEADY OR RISE SLIGHTLY FROM THE MID 40S TO
AROUND 50 DURING THE AFTERNOON. THE LOW WILL THEN MOVE INTO ONTARIO
TONIGHT AND PULL COLDER AIR INTO THE REGION ON INCREASING WESTERLY
WIND. GUSTS INCREASING TO NEAR 30 MPH LATE IN THE NIGHT WILL HELP
CARRY MIN TEMPERATURES BELOW THE FREEZING MARK BY SUNRISE WEDNESDAY.
A MIX OF RAIN AND SNOW CHANGING TO SNOW WILL BE POSSIBLE ON THE
TRAILING EDGE OF THE PRECIPITATION PATTERN OVER THE SAGINAW VALLEY
AND NORTHERN THUMB BUT WITH LITTLE TO NO ACCUMULATION EXPECTED.

EARLY MORNING SATELLITE IMAGERY SHOWS THE MID LEVEL DRY SLOT
ASSOCIATED WITH THE UPPER LOW SLIDING OVER LOWER MICHIGAN AT PRESS
TIME. THE MID LEVEL DRY AIR WILL LIMIT PRECIPITATION TO DRIZZLE IN
DEEP BOUNDARY LAYER MOISTURE AHEAD OF AND WITHIN THE SURFACE
OCCLUDED FRONT. DRIZZLE AND FOG WILL CONTINUE WITHIN THE OCCLUSION
AS IT LEADS THE SURFACE LOW THROUGH LOWER MICHIGAN WHILE COVERAGE OF
SHOWERS INCREASES AGAIN FROM ABOUT MID MORNING THROUGH THE REST OF
THE DAY. EARLY MORNING RADAR COMPOSITE AND MODEL FIELDS INDICATE
SHOWERS RELOADING OVER INDIANA AS A NEW ROUND OF ISENTROPIC ASCENT
INTERACTS WITH DYNAMIC FORCING OF THE UPPER LOW. THE ASSOCIATED COLD
POOL ALOFT...NEAR -25C AT 500 MB...WILL ALSO CONTRIBUTE ELEVATED
INSTABILITY TO AID IN EXPANSION OF THE RAIN PATTERN. COVERAGE MAY
NOT BE SOLID THROUGHOUT THE DAY BUT ENTRY LEVEL CATEGORICAL POPS ARE
A GOOD FIT AS THE UPPER LOW OPENS OVER LOWER MICHIGAN AND SETS UP A
WELL ORGANIZED BAND OF DEFORMATION TO ENHANCE THE OCCLUSION.

THE NORTHERN STREAM UPPER WAVE OVER CENTRAL CANADA TODAY WILL MOVE
INTO THE UPPER MIDWEST TONIGHT AND KICK THE GREAT LAKES SYSTEM OUT
OF THE AREA. DRY AIR BETWEEN THE TWO SYSTEMS WILL BRING AN END TO
PRECIPITATION FROM SW TO NE OVER LOWER MICHIGAN DURING THE OVERNIGHT
HOURS. THE EXCEPTION WILL BE THE SAGINAW VALLEY AND NORTHERN THUMB
NEAR THE SOUTH FLANK OF MID LEVEL DEFORMATION STRUNG OUT BETWEEN THE
TWO UPPER WAVES. A LIGHT MIX OF RAIN AND SNOW IS LIKELY THERE AS
COLDER AIR INVADES THE LOW LEVELS. MODEL PROJECTIONS OF LOW LEVEL
THICKNESS AND FORECAST SOUNDINGS SUGGEST ALL RAIN TO START THE NIGHT
THEN BECOMING MIXED WITH AND CHANGING TO SNOW AROUND AND AFTER
MIDNIGHT. AT THIS POINT...THE SLIGHTLY LATER TIMING ON THIS
TRANSITION COMBINED WITH A SLOW BUT STEADY DOWNWARD DRIFT IN SURFACE
TEMPERATURES WILL LIMIT ANY ACCUMULATION TO POSSIBLY A SLUSHY
COATING BY SUNRISE WEDNESDAY. WIND GUSTS WILL BE DRIVEN BY THE LOW
LEVEL COLD ADVECTION AND MIXED LAYER DEEPENING TO ABOUT 900 MB AFTER
MIDNIGHT. PEAK WIND GUSTS NEAR 30 MPH SUGGESTED BY MODEL SOUNDINGS
APPEARS REASONABLE GIVEN THE SURFACE LOW IS FILLING WITH TIME AS IT
EXITS INTO ONTARIO.

LONG TERM...WEDNESDAY THROUGH MONDAY

A CLOSED 500 MB LOW WILL TRACK EAST SOUTHEAST THROUGH THE NORTHERN
GREAT LAKES ON WEDNESDAY WITH A STRONG PV ANOMALY MAKING ITS WAY
THROUGH SOUTHERN LOWER MICHIGAN.  THIS WILL BE OCCURRING AS THE
STRONGEST 850 MB COLD AIR ADVECTION TAKES PLACE WITH TEMPERATURES
PLUNGING TO -10 TO -12 CELSIUS.  THE STRONG LOW AND COLD AIR
ADVECTION WILL CAUSE WESTERLY WINDS TO INCREASE TO 20 TO 30 MPH ON
WEDNESDAY. IN ADDITION SOME LIGHT SNOW AND FLURRIES WILL BE POSSIBLE
WITH THE LIFT AND COLD AIR IN PLACE.  MOISTURE WILL BE THE LIMITING
FACTOR ON WEDNESDAY AS MODEL SOUNDINGS SHOW A FAIRLY SHALLOW LAYER
OF MOISTURE IN PLACE ACROSS MOST OF THE CWA. THE DEEPEST MOISTURE
WILL BE ACROSS THE SAGINAW VALLEY AND THUMB REGION...WHERE SNOWFALL
AMOUNTS ARE EXPECTED TO BE HALF OF AN INCH OR LESS. ACROSS THE
SOUTHERN CWA JUST SOME LAKE MICHIGAN FLURRIES OR LIGHT SNOW IS
EXPECTED AS THE FLOW BACKS TO THE WEST NORTHWEST.

RIDGING THEN SLOWLY WORKS ITS WAY ACROSS THE WESTERN GREAT LAKES
WEDNESDAY NIGHT AND THURSDAY...PUSHING ANY CHANCE OF SNOW OFF TO
EAST AS WINDS TURN TO A MORE NORTHWESTERLY DIRECTION.  UNDER THIS
SETUP THE EXTREME EASTERN THUMB MAY GET BRUSHED WITH SOME FLURRY
ACTIVITY...HOWEVER WINDS APPEAR TO BE TOO WEST TO MAKE MUCH OF AN
IMPACT ACROSS THIS AREA. THE PATTERN THEN GOES FAIRLY DRY FOR THE
REMAINDER OF THE FORECAST AS THIS RIDGE BUILDS IN ACROSS THE GREAT
LAKES REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.  THE MAIN
SYSTEM OF CONCERN DURING THIS WEEKEND IS A SYSTEM EMERGING OUT OF
THE SOUTHERN PLAINS AND TRACKING THROUGH THE SOUTHEASTERN CONUS AND
EVENTUALLY OFF THE COAST OF NEW ENGLAND. HOWEVER THE AFOREMENTIONED
HIGH PRESSURE IN PLACE IS EXPECTED TO KEEP THIS SYSTEM WELL TO OUR
SOUTH AS IT FEEDS DRY AIR IN FROM CANADA. ALTHOUGH THE PATTERN WILL
BE DECIDEDLY COLDER THAN THE LAST FEW DAYS...TEMPERATURES WILL
ACTUALLY BE FAIRLY CLOSE TO NORMAL DURING THIS PERIOD AS THE COLDEST
AIR STAYS LOCKED IN ACROSS THE ARCTIC.

MARINE...

AS AN OCCLUDED SURFACE LOW MOVES INTO THE GREAT LAKES REGION...A
WARM FRONT WILL LIFT NORTH THROUGH LAKE HURON AND USHER IN WARM AND
MOIST AIR. THE SURFACE LOW IS EXPECTED TO WEAKEN AS IT TRACKS ACROSS
THE REGION...BUT THERE WILL STILL BE A DECENT AREA OF COLD AIR
ADVECTION ON THE SOUTHWEST FLANK OF THE LOW. THE TIMING OF THIS
FEATURE WILL HELP INCREASE WIND SPEEDS TONIGHT AND WEDNESDAY. MODEL
SOUNDINGS SUGGEST THE PEAK WINDS WILL BE AT THE 925 MB/2000 FT
LEVEL. AT THESE HEIGHTS...WINDS COULD REACH UP TO 35 KT. PEAK MIXING
WEDNESDAY AFTERNOON MAY ALLOW FOR BRIEF GUSTS TO GALES...BUT
WIDESPREAD AND PERSISTENT GUSTS AT THAT SPEED ARE NOT LIKELY. COMMON
WIND VECTORS WILL BE 25-30KT FROM THE WEST ON WEDNESDAY. WINDS AND
WAVES WILL DROP OFF NOTICEABLY ON THURSDAY AS HIGH PRESSURE BUILDS
IN ACROSS THE GREAT LAKES. WAVES DO NOT LOOK TO REACH SMALL CRAFT
CRITERIA ACROSS PORTIONS OF THE LAKE HURON NEARSHORE AND OUTER
SAGINAW BAY UNTIL WEDNESDAY...THEREFORE WILL HOLD OFF ON ISSUING
ANY HEADLINES UNTIL LATER FORECASTS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....SC
UPDATE.......SC
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 161514
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1014 AM EST TUE DEC 16 2014

.UPDATE...

THE REGION OF RAIN ASSOCIATED WITH PUSH OF ENHANCED ISENTROPIC
ASCENT WILL CONTINUE TO PUSH NORTHWARD ACROSS THE FORECAST AREA
DURING THE REMAINDER OF THE MORNING AND WELL INTO THE AFTERNOON.
WHILE THE COVERAGE OF RAIN WILL DECREASE ACROSS METRO DETROIT AND
POINTS SOUTH DURING THE AFTERNOON AS THE LARGE SCALE FORCING
SHIFTS TO THE NORTH...RESIDUAL DEEP LAYER MOISTURE AND STEEP MID
LEVEL LAPSE RATES WILL SUPPORT SCT TO NMRS SHOWERS THROUGH THE
AFTERNOON /VERY MUCH IN LINE WITH THE CURRENT FCST/.

AMPLE LOW LEVEL MOISTURE ADVECTION ALONG A SURFACE OCCLUDED FRONT
HAS LED TO A SUBSTANTIAL AMOUNT OF FOG ACROSS SRN MI. THE SURFACE
OCCLUDED FRONT WILL LIFT NORTH OF METRO DETROIT EARLY THIS
AFTERNOON. THIS WILL OPEN THE DOOR FOR A LITTLE STRONGER SW WINDS
AND A MODEST RISE IN SFC TEMPS FROM ROUGHLY THE M 69 CORRIDOR
SOUTH. THESE FACTORS SUGGEST VISIBILITY IMPROVEMENT DURING THE
EARLY AFTERNOON. THE SFC OCCLUSION WILL TAKE LONGER TO LIFT ACROSS
THE NORTHERN HALF OF THE FORECAST AREA...LIKELY NOT PUSHING ACROSS
THE TRI CITIES AND NRN THUMB UNTIL LATE AFTERNOON. THIS WILL
SUPPORT CONTINUING THE MENTION OF FOG THROUGH THE AFTERNOON
ACROSS THE NRN HALF OF THE FORECAST AREA /GENERALLY ALONG AND
NORTH OF I-69/.

SFC OBSERVATIONS SUGGEST THERE WILL BE SOME SLIGHT RISE IN TEMPS
ACROSS METRO DETROIT THIS AFTERNOON. FARTHER NORTH HOWEVER...TEMPS
SHOULD REMAIN FAIRLY STEADY WITH THE SFC LOW AND OCCLUSION
OVERHEAD WELL INTO THE AFTERNOON. SO AN UPDATE WILL ALSO BE
ISSUED TO REFLECT THESE EXPECTED TEMP TRENDS.

&&

.AVIATION...ISSUED 647 AM EST TUE DEC 16 2014

//DISCUSSION...

A BROAD AREA OF LOW PRESSURE WILL MOVE THROUGH LOWER MICHIGAN DURING
THE DAY. THIS FEATURE WILL BRING LIFR TO THE TERMINAL CORRIDOR
MAINLY IN THE FORM OF LOW CEILING...BUT ACCOMPANIED BY IFR
VISIBILITY IN RAIN AND FOG. THESE RESTRICTIONS WILL PERSIST THROUGH
ABOUT MID AFTERNOON BEFORE GRADUAL IMPROVEMENT GETS UNDERWAY AS THE
LOW PRESSURE SYSTEM EXITS EASTWARD AND WIND SHIFTS TOWARD THE WEST
WITH GUSTS AROUND 20 KNOTS TONIGHT.

FOR DTW... LIFR CEILING WILL HOVER NEAR 300 FT DURING THE MORNING
BEFORE IMPROVING TO IFR WITH A SW WIND SHIFT BY NOON. CONSIDERING
THE SLOW ONSET OF LIFR DURING THE EARLY MORNING...THE POTENTIAL IS
LOW FOR CEILING TO FALL BELOW 200 FT COMPARED TO POINTS WEST THAT
ARE CLOSER TO THE SURFACE LOW CENTER.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY AND TONIGHT.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS RAIN.

* LOW CONFIDENCE IN CEILING BELOW 200 FT.

&&

.PREV DISCUSSION...ISSUED 353 AM EST TUE DEC 16 2014

SHORT TERM... TODAY AND TONIGHT

LOW PRESSURE SLIDING THROUGH LOWER MICHIGAN WILL MAINTAIN DAMP BUT
MILD CONDITIONS ACROSS THE AREA TODAY. AFTER THE FIRST WAVE OF RAIN
EARLIER IN THE NIGHT...DRIZZLE AND FOG WILL BE ONGOING UNTIL THE
NEXT ROUND OF SHOWERS ARRIVES DURING THE DAYLIGHT HOURS OF THE
MORNING. RAIN WILL THEN CONTINUE OFF AND ON THROUGHOUT THE DAY AS
TEMPERATURES REMAIN STEADY OR RISE SLIGHTLY FROM THE MID 40S TO
AROUND 50 DURING THE AFTERNOON. THE LOW WILL THEN MOVE INTO ONTARIO
TONIGHT AND PULL COLDER AIR INTO THE REGION ON INCREASING WESTERLY
WIND. GUSTS INCREASING TO NEAR 30 MPH LATE IN THE NIGHT WILL HELP
CARRY MIN TEMPERATURES BELOW THE FREEZING MARK BY SUNRISE WEDNESDAY.
A MIX OF RAIN AND SNOW CHANGING TO SNOW WILL BE POSSIBLE ON THE
TRAILING EDGE OF THE PRECIPITATION PATTERN OVER THE SAGINAW VALLEY
AND NORTHERN THUMB BUT WITH LITTLE TO NO ACCUMULATION EXPECTED.

EARLY MORNING SATELLITE IMAGERY SHOWS THE MID LEVEL DRY SLOT
ASSOCIATED WITH THE UPPER LOW SLIDING OVER LOWER MICHIGAN AT PRESS
TIME. THE MID LEVEL DRY AIR WILL LIMIT PRECIPITATION TO DRIZZLE IN
DEEP BOUNDARY LAYER MOISTURE AHEAD OF AND WITHIN THE SURFACE
OCCLUDED FRONT. DRIZZLE AND FOG WILL CONTINUE WITHIN THE OCCLUSION
AS IT LEADS THE SURFACE LOW THROUGH LOWER MICHIGAN WHILE COVERAGE OF
SHOWERS INCREASES AGAIN FROM ABOUT MID MORNING THROUGH THE REST OF
THE DAY. EARLY MORNING RADAR COMPOSITE AND MODEL FIELDS INDICATE
SHOWERS RELOADING OVER INDIANA AS A NEW ROUND OF ISENTROPIC ASCENT
INTERACTS WITH DYNAMIC FORCING OF THE UPPER LOW. THE ASSOCIATED COLD
POOL ALOFT...NEAR -25C AT 500 MB...WILL ALSO CONTRIBUTE ELEVATED
INSTABILITY TO AID IN EXPANSION OF THE RAIN PATTERN. COVERAGE MAY
NOT BE SOLID THROUGHOUT THE DAY BUT ENTRY LEVEL CATEGORICAL POPS ARE
A GOOD FIT AS THE UPPER LOW OPENS OVER LOWER MICHIGAN AND SETS UP A
WELL ORGANIZED BAND OF DEFORMATION TO ENHANCE THE OCCLUSION.

THE NORTHERN STREAM UPPER WAVE OVER CENTRAL CANADA TODAY WILL MOVE
INTO THE UPPER MIDWEST TONIGHT AND KICK THE GREAT LAKES SYSTEM OUT
OF THE AREA. DRY AIR BETWEEN THE TWO SYSTEMS WILL BRING AN END TO
PRECIPITATION FROM SW TO NE OVER LOWER MICHIGAN DURING THE OVERNIGHT
HOURS. THE EXCEPTION WILL BE THE SAGINAW VALLEY AND NORTHERN THUMB
NEAR THE SOUTH FLANK OF MID LEVEL DEFORMATION STRUNG OUT BETWEEN THE
TWO UPPER WAVES. A LIGHT MIX OF RAIN AND SNOW IS LIKELY THERE AS
COLDER AIR INVADES THE LOW LEVELS. MODEL PROJECTIONS OF LOW LEVEL
THICKNESS AND FORECAST SOUNDINGS SUGGEST ALL RAIN TO START THE NIGHT
THEN BECOMING MIXED WITH AND CHANGING TO SNOW AROUND AND AFTER
MIDNIGHT. AT THIS POINT...THE SLIGHTLY LATER TIMING ON THIS
TRANSITION COMBINED WITH A SLOW BUT STEADY DOWNWARD DRIFT IN SURFACE
TEMPERATURES WILL LIMIT ANY ACCUMULATION TO POSSIBLY A SLUSHY
COATING BY SUNRISE WEDNESDAY. WIND GUSTS WILL BE DRIVEN BY THE LOW
LEVEL COLD ADVECTION AND MIXED LAYER DEEPENING TO ABOUT 900 MB AFTER
MIDNIGHT. PEAK WIND GUSTS NEAR 30 MPH SUGGESTED BY MODEL SOUNDINGS
APPEARS REASONABLE GIVEN THE SURFACE LOW IS FILLING WITH TIME AS IT
EXITS INTO ONTARIO.

LONG TERM...WEDNESDAY THROUGH MONDAY

A CLOSED 500 MB LOW WILL TRACK EAST SOUTHEAST THROUGH THE NORTHERN
GREAT LAKES ON WEDNESDAY WITH A STRONG PV ANOMALY MAKING ITS WAY
THROUGH SOUTHERN LOWER MICHIGAN.  THIS WILL BE OCCURRING AS THE
STRONGEST 850 MB COLD AIR ADVECTION TAKES PLACE WITH TEMPERATURES
PLUNGING TO -10 TO -12 CELSIUS.  THE STRONG LOW AND COLD AIR
ADVECTION WILL CAUSE WESTERLY WINDS TO INCREASE TO 20 TO 30 MPH ON
WEDNESDAY. IN ADDITION SOME LIGHT SNOW AND FLURRIES WILL BE POSSIBLE
WITH THE LIFT AND COLD AIR IN PLACE.  MOISTURE WILL BE THE LIMITING
FACTOR ON WEDNESDAY AS MODEL SOUNDINGS SHOW A FAIRLY SHALLOW LAYER
OF MOISTURE IN PLACE ACROSS MOST OF THE CWA. THE DEEPEST MOISTURE
WILL BE ACROSS THE SAGINAW VALLEY AND THUMB REGION...WHERE SNOWFALL
AMOUNTS ARE EXPECTED TO BE HALF OF AN INCH OR LESS. ACROSS THE
SOUTHERN CWA JUST SOME LAKE MICHIGAN FLURRIES OR LIGHT SNOW IS
EXPECTED AS THE FLOW BACKS TO THE WEST NORTHWEST.

RIDGING THEN SLOWLY WORKS ITS WAY ACROSS THE WESTERN GREAT LAKES
WEDNESDAY NIGHT AND THURSDAY...PUSHING ANY CHANCE OF SNOW OFF TO
EAST AS WINDS TURN TO A MORE NORTHWESTERLY DIRECTION.  UNDER THIS
SETUP THE EXTREME EASTERN THUMB MAY GET BRUSHED WITH SOME FLURRY
ACTIVITY...HOWEVER WINDS APPEAR TO BE TOO WEST TO MAKE MUCH OF AN
IMPACT ACROSS THIS AREA. THE PATTERN THEN GOES FAIRLY DRY FOR THE
REMAINDER OF THE FORECAST AS THIS RIDGE BUILDS IN ACROSS THE GREAT
LAKES REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.  THE MAIN
SYSTEM OF CONCERN DURING THIS WEEKEND IS A SYSTEM EMERGING OUT OF
THE SOUTHERN PLAINS AND TRACKING THROUGH THE SOUTHEASTERN CONUS AND
EVENTUALLY OFF THE COAST OF NEW ENGLAND. HOWEVER THE AFOREMENTIONED
HIGH PRESSURE IN PLACE IS EXPECTED TO KEEP THIS SYSTEM WELL TO OUR
SOUTH AS IT FEEDS DRY AIR IN FROM CANADA. ALTHOUGH THE PATTERN WILL
BE DECIDEDLY COLDER THAN THE LAST FEW DAYS...TEMPERATURES WILL
ACTUALLY BE FAIRLY CLOSE TO NORMAL DURING THIS PERIOD AS THE COLDEST
AIR STAYS LOCKED IN ACROSS THE ARCTIC.

MARINE...

AS AN OCCLUDED SURFACE LOW MOVES INTO THE GREAT LAKES REGION...A
WARM FRONT WILL LIFT NORTH THROUGH LAKE HURON AND USHER IN WARM AND
MOIST AIR. THE SURFACE LOW IS EXPECTED TO WEAKEN AS IT TRACKS ACROSS
THE REGION...BUT THERE WILL STILL BE A DECENT AREA OF COLD AIR
ADVECTION ON THE SOUTHWEST FLANK OF THE LOW. THE TIMING OF THIS
FEATURE WILL HELP INCREASE WIND SPEEDS TONIGHT AND WEDNESDAY. MODEL
SOUNDINGS SUGGEST THE PEAK WINDS WILL BE AT THE 925 MB/2000 FT
LEVEL. AT THESE HEIGHTS...WINDS COULD REACH UP TO 35 KT. PEAK MIXING
WEDNESDAY AFTERNOON MAY ALLOW FOR BRIEF GUSTS TO GALES...BUT
WIDESPREAD AND PERSISTENT GUSTS AT THAT SPEED ARE NOT LIKELY. COMMON
WIND VECTORS WILL BE 25-30KT FROM THE WEST ON WEDNESDAY. WINDS AND
WAVES WILL DROP OFF NOTICEABLY ON THURSDAY AS HIGH PRESSURE BUILDS
IN ACROSS THE GREAT LAKES. WAVES DO NOT LOOK TO REACH SMALL CRAFT
CRITERIA ACROSS PORTIONS OF THE LAKE HURON NEARSHORE AND OUTER
SAGINAW BAY UNTIL WEDNESDAY...THEREFORE WILL HOLD OFF ON ISSUING
ANY HEADLINES UNTIL LATER FORECASTS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

UPDATE.......SC
AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 161514
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1014 AM EST TUE DEC 16 2014

.UPDATE...

THE REGION OF RAIN ASSOCIATED WITH PUSH OF ENHANCED ISENTROPIC
ASCENT WILL CONTINUE TO PUSH NORTHWARD ACROSS THE FORECAST AREA
DURING THE REMAINDER OF THE MORNING AND WELL INTO THE AFTERNOON.
WHILE THE COVERAGE OF RAIN WILL DECREASE ACROSS METRO DETROIT AND
POINTS SOUTH DURING THE AFTERNOON AS THE LARGE SCALE FORCING
SHIFTS TO THE NORTH...RESIDUAL DEEP LAYER MOISTURE AND STEEP MID
LEVEL LAPSE RATES WILL SUPPORT SCT TO NMRS SHOWERS THROUGH THE
AFTERNOON /VERY MUCH IN LINE WITH THE CURRENT FCST/.

AMPLE LOW LEVEL MOISTURE ADVECTION ALONG A SURFACE OCCLUDED FRONT
HAS LED TO A SUBSTANTIAL AMOUNT OF FOG ACROSS SRN MI. THE SURFACE
OCCLUDED FRONT WILL LIFT NORTH OF METRO DETROIT EARLY THIS
AFTERNOON. THIS WILL OPEN THE DOOR FOR A LITTLE STRONGER SW WINDS
AND A MODEST RISE IN SFC TEMPS FROM ROUGHLY THE M 69 CORRIDOR
SOUTH. THESE FACTORS SUGGEST VISIBILITY IMPROVEMENT DURING THE
EARLY AFTERNOON. THE SFC OCCLUSION WILL TAKE LONGER TO LIFT ACROSS
THE NORTHERN HALF OF THE FORECAST AREA...LIKELY NOT PUSHING ACROSS
THE TRI CITIES AND NRN THUMB UNTIL LATE AFTERNOON. THIS WILL
SUPPORT CONTINUING THE MENTION OF FOG THROUGH THE AFTERNOON
ACROSS THE NRN HALF OF THE FORECAST AREA /GENERALLY ALONG AND
NORTH OF I-69/.

SFC OBSERVATIONS SUGGEST THERE WILL BE SOME SLIGHT RISE IN TEMPS
ACROSS METRO DETROIT THIS AFTERNOON. FARTHER NORTH HOWEVER...TEMPS
SHOULD REMAIN FAIRLY STEADY WITH THE SFC LOW AND OCCLUSION
OVERHEAD WELL INTO THE AFTERNOON. SO AN UPDATE WILL ALSO BE
ISSUED TO REFLECT THESE EXPECTED TEMP TRENDS.

&&

.AVIATION...ISSUED 647 AM EST TUE DEC 16 2014

//DISCUSSION...

A BROAD AREA OF LOW PRESSURE WILL MOVE THROUGH LOWER MICHIGAN DURING
THE DAY. THIS FEATURE WILL BRING LIFR TO THE TERMINAL CORRIDOR
MAINLY IN THE FORM OF LOW CEILING...BUT ACCOMPANIED BY IFR
VISIBILITY IN RAIN AND FOG. THESE RESTRICTIONS WILL PERSIST THROUGH
ABOUT MID AFTERNOON BEFORE GRADUAL IMPROVEMENT GETS UNDERWAY AS THE
LOW PRESSURE SYSTEM EXITS EASTWARD AND WIND SHIFTS TOWARD THE WEST
WITH GUSTS AROUND 20 KNOTS TONIGHT.

FOR DTW... LIFR CEILING WILL HOVER NEAR 300 FT DURING THE MORNING
BEFORE IMPROVING TO IFR WITH A SW WIND SHIFT BY NOON. CONSIDERING
THE SLOW ONSET OF LIFR DURING THE EARLY MORNING...THE POTENTIAL IS
LOW FOR CEILING TO FALL BELOW 200 FT COMPARED TO POINTS WEST THAT
ARE CLOSER TO THE SURFACE LOW CENTER.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY AND TONIGHT.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS RAIN.

* LOW CONFIDENCE IN CEILING BELOW 200 FT.

&&

.PREV DISCUSSION...ISSUED 353 AM EST TUE DEC 16 2014

SHORT TERM... TODAY AND TONIGHT

LOW PRESSURE SLIDING THROUGH LOWER MICHIGAN WILL MAINTAIN DAMP BUT
MILD CONDITIONS ACROSS THE AREA TODAY. AFTER THE FIRST WAVE OF RAIN
EARLIER IN THE NIGHT...DRIZZLE AND FOG WILL BE ONGOING UNTIL THE
NEXT ROUND OF SHOWERS ARRIVES DURING THE DAYLIGHT HOURS OF THE
MORNING. RAIN WILL THEN CONTINUE OFF AND ON THROUGHOUT THE DAY AS
TEMPERATURES REMAIN STEADY OR RISE SLIGHTLY FROM THE MID 40S TO
AROUND 50 DURING THE AFTERNOON. THE LOW WILL THEN MOVE INTO ONTARIO
TONIGHT AND PULL COLDER AIR INTO THE REGION ON INCREASING WESTERLY
WIND. GUSTS INCREASING TO NEAR 30 MPH LATE IN THE NIGHT WILL HELP
CARRY MIN TEMPERATURES BELOW THE FREEZING MARK BY SUNRISE WEDNESDAY.
A MIX OF RAIN AND SNOW CHANGING TO SNOW WILL BE POSSIBLE ON THE
TRAILING EDGE OF THE PRECIPITATION PATTERN OVER THE SAGINAW VALLEY
AND NORTHERN THUMB BUT WITH LITTLE TO NO ACCUMULATION EXPECTED.

EARLY MORNING SATELLITE IMAGERY SHOWS THE MID LEVEL DRY SLOT
ASSOCIATED WITH THE UPPER LOW SLIDING OVER LOWER MICHIGAN AT PRESS
TIME. THE MID LEVEL DRY AIR WILL LIMIT PRECIPITATION TO DRIZZLE IN
DEEP BOUNDARY LAYER MOISTURE AHEAD OF AND WITHIN THE SURFACE
OCCLUDED FRONT. DRIZZLE AND FOG WILL CONTINUE WITHIN THE OCCLUSION
AS IT LEADS THE SURFACE LOW THROUGH LOWER MICHIGAN WHILE COVERAGE OF
SHOWERS INCREASES AGAIN FROM ABOUT MID MORNING THROUGH THE REST OF
THE DAY. EARLY MORNING RADAR COMPOSITE AND MODEL FIELDS INDICATE
SHOWERS RELOADING OVER INDIANA AS A NEW ROUND OF ISENTROPIC ASCENT
INTERACTS WITH DYNAMIC FORCING OF THE UPPER LOW. THE ASSOCIATED COLD
POOL ALOFT...NEAR -25C AT 500 MB...WILL ALSO CONTRIBUTE ELEVATED
INSTABILITY TO AID IN EXPANSION OF THE RAIN PATTERN. COVERAGE MAY
NOT BE SOLID THROUGHOUT THE DAY BUT ENTRY LEVEL CATEGORICAL POPS ARE
A GOOD FIT AS THE UPPER LOW OPENS OVER LOWER MICHIGAN AND SETS UP A
WELL ORGANIZED BAND OF DEFORMATION TO ENHANCE THE OCCLUSION.

THE NORTHERN STREAM UPPER WAVE OVER CENTRAL CANADA TODAY WILL MOVE
INTO THE UPPER MIDWEST TONIGHT AND KICK THE GREAT LAKES SYSTEM OUT
OF THE AREA. DRY AIR BETWEEN THE TWO SYSTEMS WILL BRING AN END TO
PRECIPITATION FROM SW TO NE OVER LOWER MICHIGAN DURING THE OVERNIGHT
HOURS. THE EXCEPTION WILL BE THE SAGINAW VALLEY AND NORTHERN THUMB
NEAR THE SOUTH FLANK OF MID LEVEL DEFORMATION STRUNG OUT BETWEEN THE
TWO UPPER WAVES. A LIGHT MIX OF RAIN AND SNOW IS LIKELY THERE AS
COLDER AIR INVADES THE LOW LEVELS. MODEL PROJECTIONS OF LOW LEVEL
THICKNESS AND FORECAST SOUNDINGS SUGGEST ALL RAIN TO START THE NIGHT
THEN BECOMING MIXED WITH AND CHANGING TO SNOW AROUND AND AFTER
MIDNIGHT. AT THIS POINT...THE SLIGHTLY LATER TIMING ON THIS
TRANSITION COMBINED WITH A SLOW BUT STEADY DOWNWARD DRIFT IN SURFACE
TEMPERATURES WILL LIMIT ANY ACCUMULATION TO POSSIBLY A SLUSHY
COATING BY SUNRISE WEDNESDAY. WIND GUSTS WILL BE DRIVEN BY THE LOW
LEVEL COLD ADVECTION AND MIXED LAYER DEEPENING TO ABOUT 900 MB AFTER
MIDNIGHT. PEAK WIND GUSTS NEAR 30 MPH SUGGESTED BY MODEL SOUNDINGS
APPEARS REASONABLE GIVEN THE SURFACE LOW IS FILLING WITH TIME AS IT
EXITS INTO ONTARIO.

LONG TERM...WEDNESDAY THROUGH MONDAY

A CLOSED 500 MB LOW WILL TRACK EAST SOUTHEAST THROUGH THE NORTHERN
GREAT LAKES ON WEDNESDAY WITH A STRONG PV ANOMALY MAKING ITS WAY
THROUGH SOUTHERN LOWER MICHIGAN.  THIS WILL BE OCCURRING AS THE
STRONGEST 850 MB COLD AIR ADVECTION TAKES PLACE WITH TEMPERATURES
PLUNGING TO -10 TO -12 CELSIUS.  THE STRONG LOW AND COLD AIR
ADVECTION WILL CAUSE WESTERLY WINDS TO INCREASE TO 20 TO 30 MPH ON
WEDNESDAY. IN ADDITION SOME LIGHT SNOW AND FLURRIES WILL BE POSSIBLE
WITH THE LIFT AND COLD AIR IN PLACE.  MOISTURE WILL BE THE LIMITING
FACTOR ON WEDNESDAY AS MODEL SOUNDINGS SHOW A FAIRLY SHALLOW LAYER
OF MOISTURE IN PLACE ACROSS MOST OF THE CWA. THE DEEPEST MOISTURE
WILL BE ACROSS THE SAGINAW VALLEY AND THUMB REGION...WHERE SNOWFALL
AMOUNTS ARE EXPECTED TO BE HALF OF AN INCH OR LESS. ACROSS THE
SOUTHERN CWA JUST SOME LAKE MICHIGAN FLURRIES OR LIGHT SNOW IS
EXPECTED AS THE FLOW BACKS TO THE WEST NORTHWEST.

RIDGING THEN SLOWLY WORKS ITS WAY ACROSS THE WESTERN GREAT LAKES
WEDNESDAY NIGHT AND THURSDAY...PUSHING ANY CHANCE OF SNOW OFF TO
EAST AS WINDS TURN TO A MORE NORTHWESTERLY DIRECTION.  UNDER THIS
SETUP THE EXTREME EASTERN THUMB MAY GET BRUSHED WITH SOME FLURRY
ACTIVITY...HOWEVER WINDS APPEAR TO BE TOO WEST TO MAKE MUCH OF AN
IMPACT ACROSS THIS AREA. THE PATTERN THEN GOES FAIRLY DRY FOR THE
REMAINDER OF THE FORECAST AS THIS RIDGE BUILDS IN ACROSS THE GREAT
LAKES REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.  THE MAIN
SYSTEM OF CONCERN DURING THIS WEEKEND IS A SYSTEM EMERGING OUT OF
THE SOUTHERN PLAINS AND TRACKING THROUGH THE SOUTHEASTERN CONUS AND
EVENTUALLY OFF THE COAST OF NEW ENGLAND. HOWEVER THE AFOREMENTIONED
HIGH PRESSURE IN PLACE IS EXPECTED TO KEEP THIS SYSTEM WELL TO OUR
SOUTH AS IT FEEDS DRY AIR IN FROM CANADA. ALTHOUGH THE PATTERN WILL
BE DECIDEDLY COLDER THAN THE LAST FEW DAYS...TEMPERATURES WILL
ACTUALLY BE FAIRLY CLOSE TO NORMAL DURING THIS PERIOD AS THE COLDEST
AIR STAYS LOCKED IN ACROSS THE ARCTIC.

MARINE...

AS AN OCCLUDED SURFACE LOW MOVES INTO THE GREAT LAKES REGION...A
WARM FRONT WILL LIFT NORTH THROUGH LAKE HURON AND USHER IN WARM AND
MOIST AIR. THE SURFACE LOW IS EXPECTED TO WEAKEN AS IT TRACKS ACROSS
THE REGION...BUT THERE WILL STILL BE A DECENT AREA OF COLD AIR
ADVECTION ON THE SOUTHWEST FLANK OF THE LOW. THE TIMING OF THIS
FEATURE WILL HELP INCREASE WIND SPEEDS TONIGHT AND WEDNESDAY. MODEL
SOUNDINGS SUGGEST THE PEAK WINDS WILL BE AT THE 925 MB/2000 FT
LEVEL. AT THESE HEIGHTS...WINDS COULD REACH UP TO 35 KT. PEAK MIXING
WEDNESDAY AFTERNOON MAY ALLOW FOR BRIEF GUSTS TO GALES...BUT
WIDESPREAD AND PERSISTENT GUSTS AT THAT SPEED ARE NOT LIKELY. COMMON
WIND VECTORS WILL BE 25-30KT FROM THE WEST ON WEDNESDAY. WINDS AND
WAVES WILL DROP OFF NOTICEABLY ON THURSDAY AS HIGH PRESSURE BUILDS
IN ACROSS THE GREAT LAKES. WAVES DO NOT LOOK TO REACH SMALL CRAFT
CRITERIA ACROSS PORTIONS OF THE LAKE HURON NEARSHORE AND OUTER
SAGINAW BAY UNTIL WEDNESDAY...THEREFORE WILL HOLD OFF ON ISSUING
ANY HEADLINES UNTIL LATER FORECASTS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

UPDATE.......SC
AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





000
FXUS63 KDTX 161147
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
647 AM EST TUE DEC 16 2014

.AVIATION...

//DISCUSSION...

A BROAD AREA OF LOW PRESSURE WILL MOVE THROUGH LOWER MICHIGAN DURING
THE DAY. THIS FEATURE WILL BRING LIFR TO THE TERMINAL CORRIDOR
MAINLY IN THE FORM OF LOW CEILING...BUT ACCOMPANIED BY IFR
VISIBILITY IN RAIN AND FOG. THESE RESTRICTIONS WILL PERSIST THROUGH
ABOUT MID AFTERNOON BEFORE GRADUAL IMPROVEMENT GETS UNDERWAY AS THE
LOW PRESSURE SYSTEM EXITS EASTWARD AND WIND SHIFTS TOWARD THE WEST
WITH GUSTS AROUND 20 KNOTS TONIGHT.

FOR DTW... LIFR CEILING WILL HOVER NEAR 300 FT DURING THE MORNING
BEFORE IMPROVING TO IFR WITH A SW WIND SHIFT BY NOON. CONSIDERING
THE SLOW ONSET OF LIFR DURING THE EARLY MORNING...THE POTENTIAL IS
LOW FOR CEILING TO FALL BELOW 200 FT COMPARED TO POINTS WEST THAT
ARE CLOSER TO THE SURFACE LOW CENTER.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY AND TONIGHT.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS RAIN.

* LOW CONFIDENCE IN CEILING BELOW 200 FT.

&&

.PREV DISCUSSION...ISSUED 353 AM EST TUE DEC 16 2014

SHORT TERM... TODAY AND TONIGHT

LOW PRESSURE SLIDING THROUGH LOWER MICHIGAN WILL MAINTAIN DAMP BUT
MILD CONDITIONS ACROSS THE AREA TODAY. AFTER THE FIRST WAVE OF RAIN
EARLIER IN THE NIGHT...DRIZZLE AND FOG WILL BE ONGOING UNTIL THE
NEXT ROUND OF SHOWERS ARRIVES DURING THE DAYLIGHT HOURS OF THE
MORNING. RAIN WILL THEN CONTINUE OFF AND ON THROUGHOUT THE DAY AS
TEMPERATURES REMAIN STEADY OR RISE SLIGHTLY FROM THE MID 40S TO
AROUND 50 DURING THE AFTERNOON. THE LOW WILL THEN MOVE INTO ONTARIO
TONIGHT AND PULL COLDER AIR INTO THE REGION ON INCREASING WESTERLY
WIND. GUSTS INCREASING TO NEAR 30 MPH LATE IN THE NIGHT WILL HELP
CARRY MIN TEMPERATURES BELOW THE FREEZING MARK BY SUNRISE WEDNESDAY.
A MIX OF RAIN AND SNOW CHANGING TO SNOW WILL BE POSSIBLE ON THE
TRAILING EDGE OF THE PRECIPITATION PATTERN OVER THE SAGINAW VALLEY
AND NORTHERN THUMB BUT WITH LITTLE TO NO ACCUMULATION EXPECTED.

EARLY MORNING SATELLITE IMAGERY SHOWS THE MID LEVEL DRY SLOT
ASSOCIATED WITH THE UPPER LOW SLIDING OVER LOWER MICHIGAN AT PRESS
TIME. THE MID LEVEL DRY AIR WILL LIMIT PRECIPITATION TO DRIZZLE IN
DEEP BOUNDARY LAYER MOISTURE AHEAD OF AND WITHIN THE SURFACE
OCCLUDED FRONT. DRIZZLE AND FOG WILL CONTINUE WITHIN THE OCCLUSION
AS IT LEADS THE SURFACE LOW THROUGH LOWER MICHIGAN WHILE COVERAGE OF
SHOWERS INCREASES AGAIN FROM ABOUT MID MORNING THROUGH THE REST OF
THE DAY. EARLY MORNING RADAR COMPOSITE AND MODEL FIELDS INDICATE
SHOWERS RELOADING OVER INDIANA AS A NEW ROUND OF ISENTROPIC ASCENT
INTERACTS WITH DYNAMIC FORCING OF THE UPPER LOW. THE ASSOCIATED COLD
POOL ALOFT...NEAR -25C AT 500 MB...WILL ALSO CONTRIBUTE ELEVATED
INSTABILITY TO AID IN EXPANSION OF THE RAIN PATTERN. COVERAGE MAY
NOT BE SOLID THROUGHOUT THE DAY BUT ENTRY LEVEL CATEGORICAL POPS ARE
A GOOD FIT AS THE UPPER LOW OPENS OVER LOWER MICHIGAN AND SETS UP A
WELL ORGANIZED BAND OF DEFORMATION TO ENHANCE THE OCCLUSION.

THE NORTHERN STREAM UPPER WAVE OVER CENTRAL CANADA TODAY WILL MOVE
INTO THE UPPER MIDWEST TONIGHT AND KICK THE GREAT LAKES SYSTEM OUT
OF THE AREA. DRY AIR BETWEEN THE TWO SYSTEMS WILL BRING AN END TO
PRECIPITATION FROM SW TO NE OVER LOWER MICHIGAN DURING THE OVERNIGHT
HOURS. THE EXCEPTION WILL BE THE SAGINAW VALLEY AND NORTHERN THUMB
NEAR THE SOUTH FLANK OF MID LEVEL DEFORMATION STRUNG OUT BETWEEN THE
TWO UPPER WAVES. A LIGHT MIX OF RAIN AND SNOW IS LIKELY THERE AS
COLDER AIR INVADES THE LOW LEVELS. MODEL PROJECTIONS OF LOW LEVEL
THICKNESS AND FORECAST SOUNDINGS SUGGEST ALL RAIN TO START THE NIGHT
THEN BECOMING MIXED WITH AND CHANGING TO SNOW AROUND AND AFTER
MIDNIGHT. AT THIS POINT...THE SLIGHTLY LATER TIMING ON THIS
TRANSITION COMBINED WITH A SLOW BUT STEADY DOWNWARD DRIFT IN SURFACE
TEMPERATURES WILL LIMIT ANY ACCUMULATION TO POSSIBLY A SLUSHY
COATING BY SUNRISE WEDNESDAY. WIND GUSTS WILL BE DRIVEN BY THE LOW
LEVEL COLD ADVECTION AND MIXED LAYER DEEPENING TO ABOUT 900 MB AFTER
MIDNIGHT. PEAK WIND GUSTS NEAR 30 MPH SUGGESTED BY MODEL SOUNDINGS
APPEARS REASONABLE GIVEN THE SURFACE LOW IS FILLING WITH TIME AS IT
EXITS INTO ONTARIO.

LONG TERM...WEDNESDAY THROUGH MONDAY

A CLOSED 500 MB LOW WILL TRACK EAST SOUTHEAST THROUGH THE NORTHERN
GREAT LAKES ON WEDNESDAY WITH A STRONG PV ANOMALY MAKING ITS WAY
THROUGH SOUTHERN LOWER MICHIGAN.  THIS WILL BE OCCURRING AS THE
STRONGEST 850 MB COLD AIR ADVECTION TAKES PLACE WITH TEMPERATURES
PLUNGING TO -10 TO -12 CELSIUS.  THE STRONG LOW AND COLD AIR
ADVECTION WILL CAUSE WESTERLY WINDS TO INCREASE TO 20 TO 30 MPH ON
WEDNESDAY. IN ADDITION SOME LIGHT SNOW AND FLURRIES WILL BE POSSIBLE
WITH THE LIFT AND COLD AIR IN PLACE.  MOISTURE WILL BE THE LIMITING
FACTOR ON WEDNESDAY AS MODEL SOUNDINGS SHOW A FAIRLY SHALLOW LAYER
OF MOISTURE IN PLACE ACROSS MOST OF THE CWA. THE DEEPEST MOISTURE
WILL BE ACROSS THE SAGINAW VALLEY AND THUMB REGION...WHERE SNOWFALL
AMOUNTS ARE EXPECTED TO BE HALF OF AN INCH OR LESS. ACROSS THE
SOUTHERN CWA JUST SOME LAKE MICHIGAN FLURRIES OR LIGHT SNOW IS
EXPECTED AS THE FLOW BACKS TO THE WEST NORTHWEST.

RIDGING THEN SLOWLY WORKS ITS WAY ACROSS THE WESTERN GREAT LAKES
WEDNESDAY NIGHT AND THURSDAY...PUSHING ANY CHANCE OF SNOW OFF TO
EAST AS WINDS TURN TO A MORE NORTHWESTERLY DIRECTION.  UNDER THIS
SETUP THE EXTREME EASTERN THUMB MAY GET BRUSHED WITH SOME FLURRY
ACTIVITY...HOWEVER WINDS APPEAR TO BE TOO WEST TO MAKE MUCH OF AN
IMPACT ACROSS THIS AREA. THE PATTERN THEN GOES FAIRLY DRY FOR THE
REMAINDER OF THE FORECAST AS THIS RIDGE BUILDS IN ACROSS THE GREAT
LAKES REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.  THE MAIN
SYSTEM OF CONCERN DURING THIS WEEKEND IS A SYSTEM EMERGING OUT OF
THE SOUTHERN PLAINS AND TRACKING THROUGH THE SOUTHEASTERN CONUS AND
EVENTUALLY OFF THE COAST OF NEW ENGLAND. HOWEVER THE AFOREMENTIONED
HIGH PRESSURE IN PLACE IS EXPECTED TO KEEP THIS SYSTEM WELL TO OUR
SOUTH AS IT FEEDS DRY AIR IN FROM CANADA. ALTHOUGH THE PATTERN WILL
BE DECIDEDLY COLDER THAN THE LAST FEW DAYS...TEMPERATURES WILL
ACTUALLY BE FAIRLY CLOSE TO NORMAL DURING THIS PERIOD AS THE COLDEST
AIR STAYS LOCKED IN ACROSS THE ARCTIC.

MARINE...

AS AN OCCLUDED SURFACE LOW MOVES INTO THE GREAT LAKES REGION...A
WARM FRONT WILL LIFT NORTH THROUGH LAKE HURON AND USHER IN WARM AND
MOIST AIR. THE SURFACE LOW IS EXPECTED TO WEAKEN AS IT TRACKS ACROSS
THE REGION...BUT THERE WILL STILL BE A DECENT AREA OF COLD AIR
ADVECTION ON THE SOUTHWEST FLANK OF THE LOW. THE TIMING OF THIS
FEATURE WILL HELP INCREASE WIND SPEEDS TONIGHT AND WEDNESDAY. MODEL
SOUNDINGS SUGGEST THE PEAK WINDS WILL BE AT THE 925 MB/2000 FT
LEVEL. AT THESE HEIGHTS...WINDS COULD REACH UP TO 35 KT. PEAK MIXING
WEDNESDAY AFTERNOON MAY ALLOW FOR BRIEF GUSTS TO GALES...BUT
WIDESPREAD AND PERSISTENT GUSTS AT THAT SPEED ARE NOT LIKELY. COMMON
WIND VECTORS WILL BE 25-30KT FROM THE WEST ON WEDNESDAY. WINDS AND
WAVES WILL DROP OFF NOTICEABLY ON THURSDAY AS HIGH PRESSURE BUILDS
IN ACROSS THE GREAT LAKES. WAVES DO NOT LOOK TO REACH SMALL CRAFT
CRITERIA ACROSS PORTIONS OF THE LAKE HURON NEARSHORE AND OUTER
SAGINAW BAY UNTIL WEDNESDAY...THEREFORE WILL HOLD OFF ON ISSUING
ANY HEADLINES UNTIL LATER FORECASTS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).




000
FXUS63 KDTX 161147
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
647 AM EST TUE DEC 16 2014

.AVIATION...

//DISCUSSION...

A BROAD AREA OF LOW PRESSURE WILL MOVE THROUGH LOWER MICHIGAN DURING
THE DAY. THIS FEATURE WILL BRING LIFR TO THE TERMINAL CORRIDOR
MAINLY IN THE FORM OF LOW CEILING...BUT ACCOMPANIED BY IFR
VISIBILITY IN RAIN AND FOG. THESE RESTRICTIONS WILL PERSIST THROUGH
ABOUT MID AFTERNOON BEFORE GRADUAL IMPROVEMENT GETS UNDERWAY AS THE
LOW PRESSURE SYSTEM EXITS EASTWARD AND WIND SHIFTS TOWARD THE WEST
WITH GUSTS AROUND 20 KNOTS TONIGHT.

FOR DTW... LIFR CEILING WILL HOVER NEAR 300 FT DURING THE MORNING
BEFORE IMPROVING TO IFR WITH A SW WIND SHIFT BY NOON. CONSIDERING
THE SLOW ONSET OF LIFR DURING THE EARLY MORNING...THE POTENTIAL IS
LOW FOR CEILING TO FALL BELOW 200 FT COMPARED TO POINTS WEST THAT
ARE CLOSER TO THE SURFACE LOW CENTER.

//DTW THRESHOLD THREATS...

* HIGH CONFIDENCE IN CEILING BELOW 5000 FEET TODAY AND TONIGHT.

* HIGH CONFIDENCE IN PRECIPITATION TYPE FALLING AS RAIN.

* LOW CONFIDENCE IN CEILING BELOW 200 FT.

&&

.PREV DISCUSSION...ISSUED 353 AM EST TUE DEC 16 2014

SHORT TERM... TODAY AND TONIGHT

LOW PRESSURE SLIDING THROUGH LOWER MICHIGAN WILL MAINTAIN DAMP BUT
MILD CONDITIONS ACROSS THE AREA TODAY. AFTER THE FIRST WAVE OF RAIN
EARLIER IN THE NIGHT...DRIZZLE AND FOG WILL BE ONGOING UNTIL THE
NEXT ROUND OF SHOWERS ARRIVES DURING THE DAYLIGHT HOURS OF THE
MORNING. RAIN WILL THEN CONTINUE OFF AND ON THROUGHOUT THE DAY AS
TEMPERATURES REMAIN STEADY OR RISE SLIGHTLY FROM THE MID 40S TO
AROUND 50 DURING THE AFTERNOON. THE LOW WILL THEN MOVE INTO ONTARIO
TONIGHT AND PULL COLDER AIR INTO THE REGION ON INCREASING WESTERLY
WIND. GUSTS INCREASING TO NEAR 30 MPH LATE IN THE NIGHT WILL HELP
CARRY MIN TEMPERATURES BELOW THE FREEZING MARK BY SUNRISE WEDNESDAY.
A MIX OF RAIN AND SNOW CHANGING TO SNOW WILL BE POSSIBLE ON THE
TRAILING EDGE OF THE PRECIPITATION PATTERN OVER THE SAGINAW VALLEY
AND NORTHERN THUMB BUT WITH LITTLE TO NO ACCUMULATION EXPECTED.

EARLY MORNING SATELLITE IMAGERY SHOWS THE MID LEVEL DRY SLOT
ASSOCIATED WITH THE UPPER LOW SLIDING OVER LOWER MICHIGAN AT PRESS
TIME. THE MID LEVEL DRY AIR WILL LIMIT PRECIPITATION TO DRIZZLE IN
DEEP BOUNDARY LAYER MOISTURE AHEAD OF AND WITHIN THE SURFACE
OCCLUDED FRONT. DRIZZLE AND FOG WILL CONTINUE WITHIN THE OCCLUSION
AS IT LEADS THE SURFACE LOW THROUGH LOWER MICHIGAN WHILE COVERAGE OF
SHOWERS INCREASES AGAIN FROM ABOUT MID MORNING THROUGH THE REST OF
THE DAY. EARLY MORNING RADAR COMPOSITE AND MODEL FIELDS INDICATE
SHOWERS RELOADING OVER INDIANA AS A NEW ROUND OF ISENTROPIC ASCENT
INTERACTS WITH DYNAMIC FORCING OF THE UPPER LOW. THE ASSOCIATED COLD
POOL ALOFT...NEAR -25C AT 500 MB...WILL ALSO CONTRIBUTE ELEVATED
INSTABILITY TO AID IN EXPANSION OF THE RAIN PATTERN. COVERAGE MAY
NOT BE SOLID THROUGHOUT THE DAY BUT ENTRY LEVEL CATEGORICAL POPS ARE
A GOOD FIT AS THE UPPER LOW OPENS OVER LOWER MICHIGAN AND SETS UP A
WELL ORGANIZED BAND OF DEFORMATION TO ENHANCE THE OCCLUSION.

THE NORTHERN STREAM UPPER WAVE OVER CENTRAL CANADA TODAY WILL MOVE
INTO THE UPPER MIDWEST TONIGHT AND KICK THE GREAT LAKES SYSTEM OUT
OF THE AREA. DRY AIR BETWEEN THE TWO SYSTEMS WILL BRING AN END TO
PRECIPITATION FROM SW TO NE OVER LOWER MICHIGAN DURING THE OVERNIGHT
HOURS. THE EXCEPTION WILL BE THE SAGINAW VALLEY AND NORTHERN THUMB
NEAR THE SOUTH FLANK OF MID LEVEL DEFORMATION STRUNG OUT BETWEEN THE
TWO UPPER WAVES. A LIGHT MIX OF RAIN AND SNOW IS LIKELY THERE AS
COLDER AIR INVADES THE LOW LEVELS. MODEL PROJECTIONS OF LOW LEVEL
THICKNESS AND FORECAST SOUNDINGS SUGGEST ALL RAIN TO START THE NIGHT
THEN BECOMING MIXED WITH AND CHANGING TO SNOW AROUND AND AFTER
MIDNIGHT. AT THIS POINT...THE SLIGHTLY LATER TIMING ON THIS
TRANSITION COMBINED WITH A SLOW BUT STEADY DOWNWARD DRIFT IN SURFACE
TEMPERATURES WILL LIMIT ANY ACCUMULATION TO POSSIBLY A SLUSHY
COATING BY SUNRISE WEDNESDAY. WIND GUSTS WILL BE DRIVEN BY THE LOW
LEVEL COLD ADVECTION AND MIXED LAYER DEEPENING TO ABOUT 900 MB AFTER
MIDNIGHT. PEAK WIND GUSTS NEAR 30 MPH SUGGESTED BY MODEL SOUNDINGS
APPEARS REASONABLE GIVEN THE SURFACE LOW IS FILLING WITH TIME AS IT
EXITS INTO ONTARIO.

LONG TERM...WEDNESDAY THROUGH MONDAY

A CLOSED 500 MB LOW WILL TRACK EAST SOUTHEAST THROUGH THE NORTHERN
GREAT LAKES ON WEDNESDAY WITH A STRONG PV ANOMALY MAKING ITS WAY
THROUGH SOUTHERN LOWER MICHIGAN.  THIS WILL BE OCCURRING AS THE
STRONGEST 850 MB COLD AIR ADVECTION TAKES PLACE WITH TEMPERATURES
PLUNGING TO -10 TO -12 CELSIUS.  THE STRONG LOW AND COLD AIR
ADVECTION WILL CAUSE WESTERLY WINDS TO INCREASE TO 20 TO 30 MPH ON
WEDNESDAY. IN ADDITION SOME LIGHT SNOW AND FLURRIES WILL BE POSSIBLE
WITH THE LIFT AND COLD AIR IN PLACE.  MOISTURE WILL BE THE LIMITING
FACTOR ON WEDNESDAY AS MODEL SOUNDINGS SHOW A FAIRLY SHALLOW LAYER
OF MOISTURE IN PLACE ACROSS MOST OF THE CWA. THE DEEPEST MOISTURE
WILL BE ACROSS THE SAGINAW VALLEY AND THUMB REGION...WHERE SNOWFALL
AMOUNTS ARE EXPECTED TO BE HALF OF AN INCH OR LESS. ACROSS THE
SOUTHERN CWA JUST SOME LAKE MICHIGAN FLURRIES OR LIGHT SNOW IS
EXPECTED AS THE FLOW BACKS TO THE WEST NORTHWEST.

RIDGING THEN SLOWLY WORKS ITS WAY ACROSS THE WESTERN GREAT LAKES
WEDNESDAY NIGHT AND THURSDAY...PUSHING ANY CHANCE OF SNOW OFF TO
EAST AS WINDS TURN TO A MORE NORTHWESTERLY DIRECTION.  UNDER THIS
SETUP THE EXTREME EASTERN THUMB MAY GET BRUSHED WITH SOME FLURRY
ACTIVITY...HOWEVER WINDS APPEAR TO BE TOO WEST TO MAKE MUCH OF AN
IMPACT ACROSS THIS AREA. THE PATTERN THEN GOES FAIRLY DRY FOR THE
REMAINDER OF THE FORECAST AS THIS RIDGE BUILDS IN ACROSS THE GREAT
LAKES REGION THROUGH THE WEEKEND AND INTO EARLY NEXT WEEK.  THE MAIN
SYSTEM OF CONCERN DURING THIS WEEKEND IS A SYSTEM EMERGING OUT OF
THE SOUTHERN PLAINS AND TRACKING THROUGH THE SOUTHEASTERN CONUS AND
EVENTUALLY OFF THE COAST OF NEW ENGLAND. HOWEVER THE AFOREMENTIONED
HIGH PRESSURE IN PLACE IS EXPECTED TO KEEP THIS SYSTEM WELL TO OUR
SOUTH AS IT FEEDS DRY AIR IN FROM CANADA. ALTHOUGH THE PATTERN WILL
BE DECIDEDLY COLDER THAN THE LAST FEW DAYS...TEMPERATURES WILL
ACTUALLY BE FAIRLY CLOSE TO NORMAL DURING THIS PERIOD AS THE COLDEST
AIR STAYS LOCKED IN ACROSS THE ARCTIC.

MARINE...

AS AN OCCLUDED SURFACE LOW MOVES INTO THE GREAT LAKES REGION...A
WARM FRONT WILL LIFT NORTH THROUGH LAKE HURON AND USHER IN WARM AND
MOIST AIR. THE SURFACE LOW IS EXPECTED TO WEAKEN AS IT TRACKS ACROSS
THE REGION...BUT THERE WILL STILL BE A DECENT AREA OF COLD AIR
ADVECTION ON THE SOUTHWEST FLANK OF THE LOW. THE TIMING OF THIS
FEATURE WILL HELP INCREASE WIND SPEEDS TONIGHT AND WEDNESDAY. MODEL
SOUNDINGS SUGGEST THE PEAK WINDS WILL BE AT THE 925 MB/2000 FT
LEVEL. AT THESE HEIGHTS...WINDS COULD REACH UP TO 35 KT. PEAK MIXING
WEDNESDAY AFTERNOON MAY ALLOW FOR BRIEF GUSTS TO GALES...BUT
WIDESPREAD AND PERSISTENT GUSTS AT THAT SPEED ARE NOT LIKELY. COMMON
WIND VECTORS WILL BE 25-30KT FROM THE WEST ON WEDNESDAY. WINDS AND
WAVES WILL DROP OFF NOTICEABLY ON THURSDAY AS HIGH PRESSURE BUILDS
IN ACROSS THE GREAT LAKES. WAVES DO NOT LOOK TO REACH SMALL CRAFT
CRITERIA ACROSS PORTIONS OF THE LAKE HURON NEARSHORE AND OUTER
SAGINAW BAY UNTIL WEDNESDAY...THEREFORE WILL HOLD OFF ON ISSUING
ANY HEADLINES UNTIL LATER FORECASTS.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

AVIATION.....BT
SHORT TERM...BT
LONG TERM....KURIMSKI
MARINE.......KURIMSKI


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).





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