Home > Products > Valid Products > AFD

000
FXUS63 KGRR 011142
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
642 AM EST SUN FEB 1 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 326 AM EST SUN FEB 1 2015

A STRENGTHENING WINTER STORM WILL DUMP QUITE A BIT OF SNOW ON
SOUTHWEST LOWER MICHIGAN TODAY INTO TONIGHT. IN ADDITION...WINDS
WILL INCREASE AND CREATE NEAR BLIZZARD CONDITIONS AT TIMES FROM 1 PM
THROUGH 1 AM. THE HEAVIEST SNOW WILL FALL ALONG/SOUTH OF I-94 WHERE
OVER A FOOT OF SNOW IS EXPECTED. SNOW ACCUMULATIONS WILL TAPER OFF
THE FARTHER NORTH YOU GO BUT EVEN IN GRAND RAPIDS AND LANSING
SNOWFALL TOTALS WILL BE CLOSE TO 10 INCHES. REALIZE THOUGH THAT
THESE TOTALS WILL BE SPREAD OUT OVER 24 HOURS. SIGNIFICANT IMPACTS
ARE EXPECTED FROM THIS AFTERNOON THROUGH TONIGHT SO THOSE PLANNING
TO TRAVEL SHOULD ALLOW PLENTY OF TIME TO REACH THEIR DESTINATION.

HIGHS WILL REMAIN BELOW FREEZING THIS WEEK WITH TEMPERATURES IN THE
TEENS MONDAY AND THURSDAY.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

FORECAST CONCERNS DEAL WITH THE DEVELOPING WINTER STORM.

WE MADE A FEW CHANGES TO THE GOING HEADLINES. BASICALLY WE NUDGED
THE HEADLINES NORTH A ROW OF COUNTIES AND NOW INCLUDE GRAND RAPIDS
IN THE WINTER STORM WARNING.

THERE IS A LOT GOING FOR THIS STORM. FIRST IT/S A SLOW MOVING LOW
THAT IS STRENGTHENING AS IT MOVES ACROSS THE NORTHERN OHIO VALLEY.
SECOND...THERE IS A 60KT LLJ AHEAD OF THE LOW THAT BRINGS IN
ABUNDANT MOISTURE FROM THE GULF. THIRD...THE TROWAL NOW WORKS INTO
FAR SOUTHERN LOWER MICHIGAN PLACING A SWEET SPOT FOR HEAVY SNOW
ACROSS THE SOUTHERN CWA. FOURTH...THE DGZ...WHILE FAIRLY HIGH UP
INITIALLY...IS RATHER LARGE AND MORE IMPORTANTLY NEARLY ISOTHERMAL.
THAT/S SHOWN TO BE CONDUCIVE FOR SNOWFALL PRODUCTION. QPF OF 2/3 TO
3/4 OF AN INCH COUPLED WITH MIXING RATIOS NEAR 18:1 WOULD YIELD
SNOWFALL ACCUMULATIONS NORTH OF A FOOT OVER THE SOUTHERN CWA AND
CLOSE TO 10 INCHES ALONG I-96. EVEN THOUGH THIS IS A LONG DURATION
EVENT...AT LEAST 30 HOURS...WE FELT THIS JUSTIFIED ADDING ANOTHER
ROW OF COUNTIES TO THE WARNING. ADDITIONALLY...TRAVEL THIS EVENING
MAY BE GREATER THAN NORMAL DUE TO SUPER BOWL RELATED EVENTS.
ALSO...THE SLOWER NATURE OF THIS SYSTEM MEANS IT WILL LIKELY DRAG ON
INTO MONDAY MORNING AND AFFECT THE MONDAY MORNING COMMUTE.

COMPOUNDING THE SNOW WILL BE THE DEVELOPMENT OF STRONG WINDS THIS
AFTERNOON. BUFKIT WIND PROFILES SUGGEST WE/LL TAP INTO 35 KNOT WINDS
AS THE COLDER AIR WORKS INTO THE SYSTEM. THIS SHOULD RESULT IN
CONSIDERABLE BLOWING AND DRIFTING...AND MAYBE NEAR BLIZZARD
CONDITIONS AT TIMES. THE WINDS WILL DIE DOWN AFTER MIDNIGHT TONIGHT
BUT CLEANUP OF THE STORM WILL LAST WELL INTO MONDAY.

SNOW WILL DIMINISH MONDAY MORNING BUT MORE LIGHT SNOW IS POSSIBLE
TUESDAY AS A TROUGH MOVES THROUGH LOWER MICHIGAN.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

THE ARCTIC COLD FRONT WITH THE LONG ADVERTISED UPPER LEVEL PV
ANOMALY PUSH THROUGH THE AREA WEDNESDAY...WITH CHANCES FOR SNOW
WINDING DOWN WEDNESDAY EVENING. ESTIMATED SNOW TOTALS ENDING
WEDNESDAY EVENING THAT INCLUDE TUESDAY ARE STILL LOOKING AROUND 1-3
INCHES WITH LOCALLY HIGHER LAKESHORE AMOUNTS...SO LITTLE IMPACT
EXPECTED WITH THIS ROUND OF SNOW.

WIDESPREAD LOWS BELOW ZERO THURSDAY MORNING SEEM QUITE POSSIBLE
GIVEN LIGHT WINDS...A DRY AIRMASS...AND LIKELY SNOWPACK. MINIMAL
LAKE EFFECT SNOW SHOWER CONCERNS THURSDAY/FRIDAY WITH VERY DRY AND
COLD AIR IN PLACE. FAVORED ECMWF SHOWS THE NEXT COLD FRONT WITH
RESPECTABLE ATTENDANT MOISTURE PUSHING INTO THE AREA SATURDAY...SO
PROSPECTS FOR SNOW NEXT WEEKEND ARE INCREASING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 642 AM EST SUN FEB 1 2015

A SNOWSTORM WILL COMMENCE THIS MORNING AND LAST WELL INTO SUNDAY
NIGHT. PERSISTENT IFR/LIFR CATEGORIES IN SNOW AND BLOWING SNOW ARE
EXPECTED...ESPECIALLY BETWEEN 18Z TODAY AND 03Z MONDAY AT THE
AZO/BTL/JXN TERMINALS ALONG THE I-94 CORRIDOR. WIND GUSTS FROM
THE NORTHEAST TO 30 KNOTS WILL BECOME MORE LIKELY BY AFTERNOON
WHICH WILL FURTHER REDUCE VISIBILITIES IN BLOWING SNOW. LIGHT RIME
ICING WILL BE POSSIBLE GENERALLY BELOW 2000 FT AGL.

&&

.HYDROLOGY...
ISSUED AT 326 AM EST SUN FEB 1 2015

WE`RE LIKELY TO SEE ICE FORMATION THIS WEEK WITH BELOW FREEZING
TEMPERATURES EXPECTED THROUGHOUT THE WEEK. RIVER LEVEL FLUCTUATIONS
MAY DEVELOP AS A RESULT OF ICE BUILDUP.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ056>059-
     064>067-071>074.

     WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ037>040-
     043>046-050>052.

LM...NONE.
&&

$$

SYNOPSIS...04
SHORT TERM...04
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...04







000
FXUS63 KGRR 011142
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
642 AM EST SUN FEB 1 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 326 AM EST SUN FEB 1 2015

A STRENGTHENING WINTER STORM WILL DUMP QUITE A BIT OF SNOW ON
SOUTHWEST LOWER MICHIGAN TODAY INTO TONIGHT. IN ADDITION...WINDS
WILL INCREASE AND CREATE NEAR BLIZZARD CONDITIONS AT TIMES FROM 1 PM
THROUGH 1 AM. THE HEAVIEST SNOW WILL FALL ALONG/SOUTH OF I-94 WHERE
OVER A FOOT OF SNOW IS EXPECTED. SNOW ACCUMULATIONS WILL TAPER OFF
THE FARTHER NORTH YOU GO BUT EVEN IN GRAND RAPIDS AND LANSING
SNOWFALL TOTALS WILL BE CLOSE TO 10 INCHES. REALIZE THOUGH THAT
THESE TOTALS WILL BE SPREAD OUT OVER 24 HOURS. SIGNIFICANT IMPACTS
ARE EXPECTED FROM THIS AFTERNOON THROUGH TONIGHT SO THOSE PLANNING
TO TRAVEL SHOULD ALLOW PLENTY OF TIME TO REACH THEIR DESTINATION.

HIGHS WILL REMAIN BELOW FREEZING THIS WEEK WITH TEMPERATURES IN THE
TEENS MONDAY AND THURSDAY.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

FORECAST CONCERNS DEAL WITH THE DEVELOPING WINTER STORM.

WE MADE A FEW CHANGES TO THE GOING HEADLINES. BASICALLY WE NUDGED
THE HEADLINES NORTH A ROW OF COUNTIES AND NOW INCLUDE GRAND RAPIDS
IN THE WINTER STORM WARNING.

THERE IS A LOT GOING FOR THIS STORM. FIRST IT/S A SLOW MOVING LOW
THAT IS STRENGTHENING AS IT MOVES ACROSS THE NORTHERN OHIO VALLEY.
SECOND...THERE IS A 60KT LLJ AHEAD OF THE LOW THAT BRINGS IN
ABUNDANT MOISTURE FROM THE GULF. THIRD...THE TROWAL NOW WORKS INTO
FAR SOUTHERN LOWER MICHIGAN PLACING A SWEET SPOT FOR HEAVY SNOW
ACROSS THE SOUTHERN CWA. FOURTH...THE DGZ...WHILE FAIRLY HIGH UP
INITIALLY...IS RATHER LARGE AND MORE IMPORTANTLY NEARLY ISOTHERMAL.
THAT/S SHOWN TO BE CONDUCIVE FOR SNOWFALL PRODUCTION. QPF OF 2/3 TO
3/4 OF AN INCH COUPLED WITH MIXING RATIOS NEAR 18:1 WOULD YIELD
SNOWFALL ACCUMULATIONS NORTH OF A FOOT OVER THE SOUTHERN CWA AND
CLOSE TO 10 INCHES ALONG I-96. EVEN THOUGH THIS IS A LONG DURATION
EVENT...AT LEAST 30 HOURS...WE FELT THIS JUSTIFIED ADDING ANOTHER
ROW OF COUNTIES TO THE WARNING. ADDITIONALLY...TRAVEL THIS EVENING
MAY BE GREATER THAN NORMAL DUE TO SUPER BOWL RELATED EVENTS.
ALSO...THE SLOWER NATURE OF THIS SYSTEM MEANS IT WILL LIKELY DRAG ON
INTO MONDAY MORNING AND AFFECT THE MONDAY MORNING COMMUTE.

COMPOUNDING THE SNOW WILL BE THE DEVELOPMENT OF STRONG WINDS THIS
AFTERNOON. BUFKIT WIND PROFILES SUGGEST WE/LL TAP INTO 35 KNOT WINDS
AS THE COLDER AIR WORKS INTO THE SYSTEM. THIS SHOULD RESULT IN
CONSIDERABLE BLOWING AND DRIFTING...AND MAYBE NEAR BLIZZARD
CONDITIONS AT TIMES. THE WINDS WILL DIE DOWN AFTER MIDNIGHT TONIGHT
BUT CLEANUP OF THE STORM WILL LAST WELL INTO MONDAY.

SNOW WILL DIMINISH MONDAY MORNING BUT MORE LIGHT SNOW IS POSSIBLE
TUESDAY AS A TROUGH MOVES THROUGH LOWER MICHIGAN.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

THE ARCTIC COLD FRONT WITH THE LONG ADVERTISED UPPER LEVEL PV
ANOMALY PUSH THROUGH THE AREA WEDNESDAY...WITH CHANCES FOR SNOW
WINDING DOWN WEDNESDAY EVENING. ESTIMATED SNOW TOTALS ENDING
WEDNESDAY EVENING THAT INCLUDE TUESDAY ARE STILL LOOKING AROUND 1-3
INCHES WITH LOCALLY HIGHER LAKESHORE AMOUNTS...SO LITTLE IMPACT
EXPECTED WITH THIS ROUND OF SNOW.

WIDESPREAD LOWS BELOW ZERO THURSDAY MORNING SEEM QUITE POSSIBLE
GIVEN LIGHT WINDS...A DRY AIRMASS...AND LIKELY SNOWPACK. MINIMAL
LAKE EFFECT SNOW SHOWER CONCERNS THURSDAY/FRIDAY WITH VERY DRY AND
COLD AIR IN PLACE. FAVORED ECMWF SHOWS THE NEXT COLD FRONT WITH
RESPECTABLE ATTENDANT MOISTURE PUSHING INTO THE AREA SATURDAY...SO
PROSPECTS FOR SNOW NEXT WEEKEND ARE INCREASING.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 642 AM EST SUN FEB 1 2015

A SNOWSTORM WILL COMMENCE THIS MORNING AND LAST WELL INTO SUNDAY
NIGHT. PERSISTENT IFR/LIFR CATEGORIES IN SNOW AND BLOWING SNOW ARE
EXPECTED...ESPECIALLY BETWEEN 18Z TODAY AND 03Z MONDAY AT THE
AZO/BTL/JXN TERMINALS ALONG THE I-94 CORRIDOR. WIND GUSTS FROM
THE NORTHEAST TO 30 KNOTS WILL BECOME MORE LIKELY BY AFTERNOON
WHICH WILL FURTHER REDUCE VISIBILITIES IN BLOWING SNOW. LIGHT RIME
ICING WILL BE POSSIBLE GENERALLY BELOW 2000 FT AGL.

&&

.HYDROLOGY...
ISSUED AT 326 AM EST SUN FEB 1 2015

WE`RE LIKELY TO SEE ICE FORMATION THIS WEEK WITH BELOW FREEZING
TEMPERATURES EXPECTED THROUGHOUT THE WEEK. RIVER LEVEL FLUCTUATIONS
MAY DEVELOP AS A RESULT OF ICE BUILDUP.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ056>059-
     064>067-071>074.

     WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ037>040-
     043>046-050>052.

LM...NONE.
&&

$$

SYNOPSIS...04
SHORT TERM...04
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...04








000
FXUS63 KGRR 010826
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
326 AM EST SUN FEB 1 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO

.SYNOPSIS...
ISSUED AT 326 AM EST SUN FEB 1 2015

A STRENGTHENING WINTER STORM WILL DUMP QUITE A BIT OF SNOW ON
SOUTHWEST LOWER MICHIGAN TODAY INTO TONIGHT. IN ADDITION...WINDS
WILL INCREASE AND CREATE NEAR BLIZZARD CONDITIONS AT TIMES FROM 1 PM
THROUGH 1 AM. THE HEAVIEST SNOW WILL FALL ALONG/SOUTH OF I-94 WHERE
OVER A FOOT OF SNOW IS EXPECTED. SNOW ACCUMULATIONS WILL TAPER OFF
THE FARTHER NORTH YOU GO BUT EVEN IN GRAND RAPIDS AND LANSING
SNOWFALL TOTALS WILL BE CLOSE TO 10 INCHES. REALIZE THOUGH THAT
THESE TOTALS WILL BE SPREAD OUT OVER 24 HOURS. SIGNIFICANT IMPACTS
ARE EXPECTED FROM THIS AFTERNOON THROUGH TONIGHT SO THOSE PLANNING
TO TRAVEL SHOULD ALLOW PLENTY OF TIME TO REACH THEIR DESTINATION.

HIGHS WILL REMAIN BELOW FREEZING THIS WEEK WITH TEMPERATURES IN THE
TEENS MONDAY AND THURSDAY.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

FORECAST CONCERNS DEAL WITH THE DEVELOPING WINTER STORM.

WE MADE A FEW CHANGES TO THE GOING HEADLINES. BASICALLY WE NUDGED
THE HEADLINES NORTH A ROW OF COUNTIES AND NOW INCLUDE GRAND RAPIDS
IN THE WINTER STORM WARNING.

THERE IS A LOT GOING FOR THIS STORM. FIRST IT/S A SLOW MOVING LOW
THAT IS STRENGTHENING AS IT MOVES ACROSS THE NORTHERN OHIO VALLEY.
SECOND...THERE IS A 60KT LLJ AHEAD OF THE LOW THAT BRINGS IN
ABUNDANT MOISTURE FROM THE GULF. THIRD...THE TROWAL NOW WORKS INTO
FAR SOUTHERN LOWER MICHIGAN PLACING A SWEET SPOT FOR HEAVY SNOW
ACROSS THE SOUTHERN CWA. FOURTH...THE DGZ...WHILE FAIRLY HIGH UP
INITIALLY...IS RATHER LARGE AND MORE IMPORTANTLY NEARLY ISOTHERMAL.
THAT/S SHOWN TO BE CONDUCIVE FOR SNOWFALL PRODUCTION. QPF OF 2/3 TO
3/4 OF AN INCH COUPLED WITH MIXING RATIOS NEAR 18:1 WOULD YIELD
SNOWFALL ACCUMULATIONS NORTH OF A FOOT OVER THE SOUTHERN CWA AND
CLOSE TO 10 INCHES ALONG I-96. EVEN THOUGH THIS IS A LONG DURATION
EVENT...AT LEAST 30 HOURS...WE FELT THIS JUSTIFIED ADDING ANOTHER
ROW OF COUNTIES TO THE WARNING. ADDITIONALLY...TRAVEL THIS EVENING
MAY BE GREATER THAN NORMAL DUE TO SUPER BOWL RELATED EVENTS.
ALSO...THE SLOWER NATURE OF THIS SYSTEM MEANS IT WILL LIKELY DRAG ON
INTO MONDAY MORNING AND AFFECT THE MONDAY MORNING COMMUTE.

COMPOUNDING THE SNOW WILL BE THE DEVELOPMENT OF STRONG WINDS THIS
AFTERNOON. BUFKIT WIND PROFILES SUGGEST WE/LL TAP INTO 35 KNOT WINDS
AS THE COLDER AIR WORKS INTO THE SYSTEM. THIS SHOULD RESULT IN
CONSIDERABLE BLOWING AND DRIFTING...AND MAYBE NEAR BLIZZARD
CONDITIONS AT TIMES. THE WINDS WILL DIE DOWN AFTER MIDNIGHT TONIGHT
BUT CLEANUP OF THE STORM WILL LAST WELL INTO MONDAY.

SNOW WILL DIMINISH MONDAY MORNING BUT MORE LIGHT SNOW IS POSSIBLE
TUESDAY AS A TROUGH MOVES THROUGH LOWER MICHIGAN.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

THE ARCTIC COLD FRONT WITH THE LONG ADVERTISED UPPER LEVEL PV
ANOMALY PUSH THROUGH THE AREA WEDNESDAY...WITH CHANCES FOR SNOW
WINDING DOWN WEDNESDAY EVENING. ESTIMATED SNOW TOTALS ENDING
WEDNESDAY EVENING THAT INCLUDE TUESDAY ARE STILL LOOKING AROUND 1-3
INCHES WITH LOCALLY HIGHER LAKESHORE AMOUNTS...SO LITTLE IMPACT
EXPECTED WITH THIS ROUND OF SNOW.

WIDESPREAD LOWS BELOW ZERO THURSDAY MORNING SEEM QUITE POSSIBLE
GIVEN LIGHT WINDS...A DRY AIRMASS...AND LIKELY SNOWPACK. MINIMAL
LAKE EFFECT SNOW SHOWER CONCERNS THURSDAY/FRIDAY WITH VERY DRY AND
COLD AIR IN PLACE. FAVORED ECMWF SHOWS THE NEXT COLD FRONT WITH
RESPECTABLE ATTENDANT MOISTURE PUSHING INTO THE AREA SATURDAY...SO
PROSPECTS FOR SNOW NEXT WEEKEND ARE INCREASING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1159 PM EST SAT JAN 31 2015

A SNOWSTORM WILL ARRIVE OVERNIGHT AND CONTINUE SUNDAY AND SUNDAY
NIGHT... BRINGING WIDESPREAD AND PERSISTENT IFR/LIFR CONDITIONS IN
SNOW AND BLOWING SNOW. THE WORST CONDITIONS IN TERMS OF SNOW
INTENSITY... BLOWING SNOW... AND STRENGTH OF THE WINDS WILL BE
BETWEEN 18Z SUNDAY AND 06Z MONDAY. SFC WINDS WILL INCREASE ON
SUNDAY OUT OF THE NORTHEAST TO 12 TO 22 KTS WITH GUSTS TO 30
KNOTS. EXPECT MODERATE ICING IN THE SNOWSTORM FROM THE SFC TO
20,000 FT.


&&

.HYDROLOGY...
ISSUED AT 326 AM EST SUN FEB 1 2015

WE`RE LIKELY TO SEE ICE FORMATION THIS WEEK WITH BELOW FREEZING
TEMPERATURES EXPECTED THROUGHOUT THE WEEK. RIVER LEVEL FLUCTUATIONS
MAY DEVELOP AS A RESULT OF ICE BUILDUP.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ056>059-
     064>067-071>074.

     WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ037>040-
     043>046-050>052.

LM...NONE.
&&

$$

SYNOPSIS...04
SHORT TERM...04
LONG TERM...TJT
AVIATION...MEADE
HYDROLOGY...04











000
FXUS63 KGRR 010826
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
326 AM EST SUN FEB 1 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO

.SYNOPSIS...
ISSUED AT 326 AM EST SUN FEB 1 2015

A STRENGTHENING WINTER STORM WILL DUMP QUITE A BIT OF SNOW ON
SOUTHWEST LOWER MICHIGAN TODAY INTO TONIGHT. IN ADDITION...WINDS
WILL INCREASE AND CREATE NEAR BLIZZARD CONDITIONS AT TIMES FROM 1 PM
THROUGH 1 AM. THE HEAVIEST SNOW WILL FALL ALONG/SOUTH OF I-94 WHERE
OVER A FOOT OF SNOW IS EXPECTED. SNOW ACCUMULATIONS WILL TAPER OFF
THE FARTHER NORTH YOU GO BUT EVEN IN GRAND RAPIDS AND LANSING
SNOWFALL TOTALS WILL BE CLOSE TO 10 INCHES. REALIZE THOUGH THAT
THESE TOTALS WILL BE SPREAD OUT OVER 24 HOURS. SIGNIFICANT IMPACTS
ARE EXPECTED FROM THIS AFTERNOON THROUGH TONIGHT SO THOSE PLANNING
TO TRAVEL SHOULD ALLOW PLENTY OF TIME TO REACH THEIR DESTINATION.

HIGHS WILL REMAIN BELOW FREEZING THIS WEEK WITH TEMPERATURES IN THE
TEENS MONDAY AND THURSDAY.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

FORECAST CONCERNS DEAL WITH THE DEVELOPING WINTER STORM.

WE MADE A FEW CHANGES TO THE GOING HEADLINES. BASICALLY WE NUDGED
THE HEADLINES NORTH A ROW OF COUNTIES AND NOW INCLUDE GRAND RAPIDS
IN THE WINTER STORM WARNING.

THERE IS A LOT GOING FOR THIS STORM. FIRST IT/S A SLOW MOVING LOW
THAT IS STRENGTHENING AS IT MOVES ACROSS THE NORTHERN OHIO VALLEY.
SECOND...THERE IS A 60KT LLJ AHEAD OF THE LOW THAT BRINGS IN
ABUNDANT MOISTURE FROM THE GULF. THIRD...THE TROWAL NOW WORKS INTO
FAR SOUTHERN LOWER MICHIGAN PLACING A SWEET SPOT FOR HEAVY SNOW
ACROSS THE SOUTHERN CWA. FOURTH...THE DGZ...WHILE FAIRLY HIGH UP
INITIALLY...IS RATHER LARGE AND MORE IMPORTANTLY NEARLY ISOTHERMAL.
THAT/S SHOWN TO BE CONDUCIVE FOR SNOWFALL PRODUCTION. QPF OF 2/3 TO
3/4 OF AN INCH COUPLED WITH MIXING RATIOS NEAR 18:1 WOULD YIELD
SNOWFALL ACCUMULATIONS NORTH OF A FOOT OVER THE SOUTHERN CWA AND
CLOSE TO 10 INCHES ALONG I-96. EVEN THOUGH THIS IS A LONG DURATION
EVENT...AT LEAST 30 HOURS...WE FELT THIS JUSTIFIED ADDING ANOTHER
ROW OF COUNTIES TO THE WARNING. ADDITIONALLY...TRAVEL THIS EVENING
MAY BE GREATER THAN NORMAL DUE TO SUPER BOWL RELATED EVENTS.
ALSO...THE SLOWER NATURE OF THIS SYSTEM MEANS IT WILL LIKELY DRAG ON
INTO MONDAY MORNING AND AFFECT THE MONDAY MORNING COMMUTE.

COMPOUNDING THE SNOW WILL BE THE DEVELOPMENT OF STRONG WINDS THIS
AFTERNOON. BUFKIT WIND PROFILES SUGGEST WE/LL TAP INTO 35 KNOT WINDS
AS THE COLDER AIR WORKS INTO THE SYSTEM. THIS SHOULD RESULT IN
CONSIDERABLE BLOWING AND DRIFTING...AND MAYBE NEAR BLIZZARD
CONDITIONS AT TIMES. THE WINDS WILL DIE DOWN AFTER MIDNIGHT TONIGHT
BUT CLEANUP OF THE STORM WILL LAST WELL INTO MONDAY.

SNOW WILL DIMINISH MONDAY MORNING BUT MORE LIGHT SNOW IS POSSIBLE
TUESDAY AS A TROUGH MOVES THROUGH LOWER MICHIGAN.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 326 AM EST SUN FEB 1 2015

THE ARCTIC COLD FRONT WITH THE LONG ADVERTISED UPPER LEVEL PV
ANOMALY PUSH THROUGH THE AREA WEDNESDAY...WITH CHANCES FOR SNOW
WINDING DOWN WEDNESDAY EVENING. ESTIMATED SNOW TOTALS ENDING
WEDNESDAY EVENING THAT INCLUDE TUESDAY ARE STILL LOOKING AROUND 1-3
INCHES WITH LOCALLY HIGHER LAKESHORE AMOUNTS...SO LITTLE IMPACT
EXPECTED WITH THIS ROUND OF SNOW.

WIDESPREAD LOWS BELOW ZERO THURSDAY MORNING SEEM QUITE POSSIBLE
GIVEN LIGHT WINDS...A DRY AIRMASS...AND LIKELY SNOWPACK. MINIMAL
LAKE EFFECT SNOW SHOWER CONCERNS THURSDAY/FRIDAY WITH VERY DRY AND
COLD AIR IN PLACE. FAVORED ECMWF SHOWS THE NEXT COLD FRONT WITH
RESPECTABLE ATTENDANT MOISTURE PUSHING INTO THE AREA SATURDAY...SO
PROSPECTS FOR SNOW NEXT WEEKEND ARE INCREASING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1159 PM EST SAT JAN 31 2015

A SNOWSTORM WILL ARRIVE OVERNIGHT AND CONTINUE SUNDAY AND SUNDAY
NIGHT... BRINGING WIDESPREAD AND PERSISTENT IFR/LIFR CONDITIONS IN
SNOW AND BLOWING SNOW. THE WORST CONDITIONS IN TERMS OF SNOW
INTENSITY... BLOWING SNOW... AND STRENGTH OF THE WINDS WILL BE
BETWEEN 18Z SUNDAY AND 06Z MONDAY. SFC WINDS WILL INCREASE ON
SUNDAY OUT OF THE NORTHEAST TO 12 TO 22 KTS WITH GUSTS TO 30
KNOTS. EXPECT MODERATE ICING IN THE SNOWSTORM FROM THE SFC TO
20,000 FT.


&&

.HYDROLOGY...
ISSUED AT 326 AM EST SUN FEB 1 2015

WE`RE LIKELY TO SEE ICE FORMATION THIS WEEK WITH BELOW FREEZING
TEMPERATURES EXPECTED THROUGHOUT THE WEEK. RIVER LEVEL FLUCTUATIONS
MAY DEVELOP AS A RESULT OF ICE BUILDUP.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ056>059-
     064>067-071>074.

     WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ037>040-
     043>046-050>052.

LM...NONE.
&&

$$

SYNOPSIS...04
SHORT TERM...04
LONG TERM...TJT
AVIATION...MEADE
HYDROLOGY...04










000
FXUS63 KGRR 010505
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1205 AM EST SUN FEB 1 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.UPDATE...
ISSUED AT 932 PM EST SAT JAN 31 2015

NO CHANGES TO THE HEADLINES. REGIONAL RADAR SHOWS PCPN SLOWLY
MOVING NORTH ACROSS INDIANA/OHIO. LIGHT SNOW WILL BEGIN AFTER
MIDNIGHT ACROSS THE WARNING/ADVISORY AREAS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1159 PM EST SAT JAN 31 2015

A SNOWSTORM WILL ARRIVE OVERNIGHT AND CONTINUE SUNDAY AND SUNDAY
NIGHT... BRINGING WIDESPREAD AND PERSISTENT IFR/LIFR CONDITIONS IN
SNOW AND BLOWING SNOW. THE WORST CONDITIONS IN TERMS OF SNOW
INTENSITY... BLOWING SNOW... AND STRENGTH OF THE WINDS WILL BE
BETWEEN 18Z SUNDAY AND 06Z MONDAY. SFC WINDS WILL INCREASE ON
SUNDAY OUT OF THE NORTHEAST TO 12 TO 22 KTS WITH GUSTS TO 30
KNOTS. EXPECT MODERATE ICING IN THE SNOWSTORM FROM THE SFC TO
20,000 FT.

&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW








000
FXUS63 KGRR 010505
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1205 AM EST SUN FEB 1 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.UPDATE...
ISSUED AT 932 PM EST SAT JAN 31 2015

NO CHANGES TO THE HEADLINES. REGIONAL RADAR SHOWS PCPN SLOWLY
MOVING NORTH ACROSS INDIANA/OHIO. LIGHT SNOW WILL BEGIN AFTER
MIDNIGHT ACROSS THE WARNING/ADVISORY AREAS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1159 PM EST SAT JAN 31 2015

A SNOWSTORM WILL ARRIVE OVERNIGHT AND CONTINUE SUNDAY AND SUNDAY
NIGHT... BRINGING WIDESPREAD AND PERSISTENT IFR/LIFR CONDITIONS IN
SNOW AND BLOWING SNOW. THE WORST CONDITIONS IN TERMS OF SNOW
INTENSITY... BLOWING SNOW... AND STRENGTH OF THE WINDS WILL BE
BETWEEN 18Z SUNDAY AND 06Z MONDAY. SFC WINDS WILL INCREASE ON
SUNDAY OUT OF THE NORTHEAST TO 12 TO 22 KTS WITH GUSTS TO 30
KNOTS. EXPECT MODERATE ICING IN THE SNOWSTORM FROM THE SFC TO
20,000 FT.

&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW







000
FXUS63 KGRR 010505
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1205 AM EST SUN FEB 1 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.UPDATE...
ISSUED AT 932 PM EST SAT JAN 31 2015

NO CHANGES TO THE HEADLINES. REGIONAL RADAR SHOWS PCPN SLOWLY
MOVING NORTH ACROSS INDIANA/OHIO. LIGHT SNOW WILL BEGIN AFTER
MIDNIGHT ACROSS THE WARNING/ADVISORY AREAS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1159 PM EST SAT JAN 31 2015

A SNOWSTORM WILL ARRIVE OVERNIGHT AND CONTINUE SUNDAY AND SUNDAY
NIGHT... BRINGING WIDESPREAD AND PERSISTENT IFR/LIFR CONDITIONS IN
SNOW AND BLOWING SNOW. THE WORST CONDITIONS IN TERMS OF SNOW
INTENSITY... BLOWING SNOW... AND STRENGTH OF THE WINDS WILL BE
BETWEEN 18Z SUNDAY AND 06Z MONDAY. SFC WINDS WILL INCREASE ON
SUNDAY OUT OF THE NORTHEAST TO 12 TO 22 KTS WITH GUSTS TO 30
KNOTS. EXPECT MODERATE ICING IN THE SNOWSTORM FROM THE SFC TO
20,000 FT.

&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW








000
FXUS63 KGRR 010505
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1205 AM EST SUN FEB 1 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.UPDATE...
ISSUED AT 932 PM EST SAT JAN 31 2015

NO CHANGES TO THE HEADLINES. REGIONAL RADAR SHOWS PCPN SLOWLY
MOVING NORTH ACROSS INDIANA/OHIO. LIGHT SNOW WILL BEGIN AFTER
MIDNIGHT ACROSS THE WARNING/ADVISORY AREAS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1159 PM EST SAT JAN 31 2015

A SNOWSTORM WILL ARRIVE OVERNIGHT AND CONTINUE SUNDAY AND SUNDAY
NIGHT... BRINGING WIDESPREAD AND PERSISTENT IFR/LIFR CONDITIONS IN
SNOW AND BLOWING SNOW. THE WORST CONDITIONS IN TERMS OF SNOW
INTENSITY... BLOWING SNOW... AND STRENGTH OF THE WINDS WILL BE
BETWEEN 18Z SUNDAY AND 06Z MONDAY. SFC WINDS WILL INCREASE ON
SUNDAY OUT OF THE NORTHEAST TO 12 TO 22 KTS WITH GUSTS TO 30
KNOTS. EXPECT MODERATE ICING IN THE SNOWSTORM FROM THE SFC TO
20,000 FT.

&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW







000
FXUS63 KGRR 010236
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
936 PM EST SAT JAN 31 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.UPDATE...
ISSUED AT 932 PM EST SAT JAN 31 2015

NO CHANGES TO THE HEADLINES. REGIONAL RADAR SHOWS PCPN SLOWLY
MOVING NORTH ACROSS INDIANA/OHIO. LIGHT SNOW WILL BEGIN AFTER
MIDNIGHT ACROSS THE WARNING/ADVISORY AREAS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 703 PM EST SAT JAN 31 2015

FLIGHT CONDITIONS WILL DETERIORATE OVERNIGHT TO IFR AS SNOW
OVERSPREADS THE AREA FROM SOUTHWEST TO NORTHEAST. THE SNOW WILL
PERSIST ALL DAY SUNDAY AND SUNDAY NIGHT WITH WIDESPREAD LIFR
LIKELY IN SNOW AND BLOWING SNOW. ONCE THE SNOW MOVES IN LATER
TONIGHT EXPECT MODERATE ICING FROM THE SFC TO 16000 FT.

IN THE NEAR TERM THERE IS CURRENTLY A COLD FRONT SAGGING SOUTH
THROUGH THE AREA. MVFR CIGS ARE WIDESPREAD BEHIND THE FRONT FROM
GRR NORTH AT 7 PM WITH VFR TO THE SOUTH. ALL THE TERMINALS SOUTH
OF GRR SHOULD ALSO BECOME MVFR BY 06Z WITH WIDESPREAD IFR BY 09Z
AND WIDESPREAD LIFR LIKELY BY 12Z SUNDAY.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW







000
FXUS63 KGRR 010236
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
936 PM EST SAT JAN 31 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.UPDATE...
ISSUED AT 932 PM EST SAT JAN 31 2015

NO CHANGES TO THE HEADLINES. REGIONAL RADAR SHOWS PCPN SLOWLY
MOVING NORTH ACROSS INDIANA/OHIO. LIGHT SNOW WILL BEGIN AFTER
MIDNIGHT ACROSS THE WARNING/ADVISORY AREAS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 703 PM EST SAT JAN 31 2015

FLIGHT CONDITIONS WILL DETERIORATE OVERNIGHT TO IFR AS SNOW
OVERSPREADS THE AREA FROM SOUTHWEST TO NORTHEAST. THE SNOW WILL
PERSIST ALL DAY SUNDAY AND SUNDAY NIGHT WITH WIDESPREAD LIFR
LIKELY IN SNOW AND BLOWING SNOW. ONCE THE SNOW MOVES IN LATER
TONIGHT EXPECT MODERATE ICING FROM THE SFC TO 16000 FT.

IN THE NEAR TERM THERE IS CURRENTLY A COLD FRONT SAGGING SOUTH
THROUGH THE AREA. MVFR CIGS ARE WIDESPREAD BEHIND THE FRONT FROM
GRR NORTH AT 7 PM WITH VFR TO THE SOUTH. ALL THE TERMINALS SOUTH
OF GRR SHOULD ALSO BECOME MVFR BY 06Z WITH WIDESPREAD IFR BY 09Z
AND WIDESPREAD LIFR LIKELY BY 12Z SUNDAY.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW








000
FXUS63 KGRR 010236
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
936 PM EST SAT JAN 31 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.UPDATE...
ISSUED AT 932 PM EST SAT JAN 31 2015

NO CHANGES TO THE HEADLINES. REGIONAL RADAR SHOWS PCPN SLOWLY
MOVING NORTH ACROSS INDIANA/OHIO. LIGHT SNOW WILL BEGIN AFTER
MIDNIGHT ACROSS THE WARNING/ADVISORY AREAS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 703 PM EST SAT JAN 31 2015

FLIGHT CONDITIONS WILL DETERIORATE OVERNIGHT TO IFR AS SNOW
OVERSPREADS THE AREA FROM SOUTHWEST TO NORTHEAST. THE SNOW WILL
PERSIST ALL DAY SUNDAY AND SUNDAY NIGHT WITH WIDESPREAD LIFR
LIKELY IN SNOW AND BLOWING SNOW. ONCE THE SNOW MOVES IN LATER
TONIGHT EXPECT MODERATE ICING FROM THE SFC TO 16000 FT.

IN THE NEAR TERM THERE IS CURRENTLY A COLD FRONT SAGGING SOUTH
THROUGH THE AREA. MVFR CIGS ARE WIDESPREAD BEHIND THE FRONT FROM
GRR NORTH AT 7 PM WITH VFR TO THE SOUTH. ALL THE TERMINALS SOUTH
OF GRR SHOULD ALSO BECOME MVFR BY 06Z WITH WIDESPREAD IFR BY 09Z
AND WIDESPREAD LIFR LIKELY BY 12Z SUNDAY.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW








000
FXUS63 KGRR 010236
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
936 PM EST SAT JAN 31 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.UPDATE...
ISSUED AT 932 PM EST SAT JAN 31 2015

NO CHANGES TO THE HEADLINES. REGIONAL RADAR SHOWS PCPN SLOWLY
MOVING NORTH ACROSS INDIANA/OHIO. LIGHT SNOW WILL BEGIN AFTER
MIDNIGHT ACROSS THE WARNING/ADVISORY AREAS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 703 PM EST SAT JAN 31 2015

FLIGHT CONDITIONS WILL DETERIORATE OVERNIGHT TO IFR AS SNOW
OVERSPREADS THE AREA FROM SOUTHWEST TO NORTHEAST. THE SNOW WILL
PERSIST ALL DAY SUNDAY AND SUNDAY NIGHT WITH WIDESPREAD LIFR
LIKELY IN SNOW AND BLOWING SNOW. ONCE THE SNOW MOVES IN LATER
TONIGHT EXPECT MODERATE ICING FROM THE SFC TO 16000 FT.

IN THE NEAR TERM THERE IS CURRENTLY A COLD FRONT SAGGING SOUTH
THROUGH THE AREA. MVFR CIGS ARE WIDESPREAD BEHIND THE FRONT FROM
GRR NORTH AT 7 PM WITH VFR TO THE SOUTH. ALL THE TERMINALS SOUTH
OF GRR SHOULD ALSO BECOME MVFR BY 06Z WITH WIDESPREAD IFR BY 09Z
AND WIDESPREAD LIFR LIKELY BY 12Z SUNDAY.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW







000
FXUS63 KGRR 010003
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
703 PM EST SAT JAN 31 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 703 PM EST SAT JAN 31 2015

FLIGHT CONDITIONS WILL DETERIORATE OVERNIGHT TO IFR AS SNOW
OVERSPREADS THE AREA FROM SOUTHWEST TO NORTHEAST. THE SNOW WILL
PERSIST ALL DAY SUNDAY AND SUNDAY NIGHT WITH WIDESPREAD LIFR
LIKELY IN SNOW AND BLOWING SNOW. ONCE THE SNOW MOVES IN LATER
TONIGHT EXPECT MODERATE ICING FROM THE SFC TO 16000 FT.

IN THE NEAR TERM THERE IS CURRENTLY A COLD FRONT SAGGING SOUTH
THROUGH THE AREA. MVFR CIGS ARE WIDESPREAD BEHIND THE FRONT FROM
GRR NORTH AT 7 PM WITH VFR TO THE SOUTH. ALL THE TERMINALS SOUTH
OF GRR SHOULD ALSO BECOME MVFR BY 06Z WITH WIDESPREAD IFR BY 09Z
AND WIDESPREAD LIFR LIKELY BY 12Z SUNDAY.

&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW







000
FXUS63 KGRR 010003
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
703 PM EST SAT JAN 31 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 703 PM EST SAT JAN 31 2015

FLIGHT CONDITIONS WILL DETERIORATE OVERNIGHT TO IFR AS SNOW
OVERSPREADS THE AREA FROM SOUTHWEST TO NORTHEAST. THE SNOW WILL
PERSIST ALL DAY SUNDAY AND SUNDAY NIGHT WITH WIDESPREAD LIFR
LIKELY IN SNOW AND BLOWING SNOW. ONCE THE SNOW MOVES IN LATER
TONIGHT EXPECT MODERATE ICING FROM THE SFC TO 16000 FT.

IN THE NEAR TERM THERE IS CURRENTLY A COLD FRONT SAGGING SOUTH
THROUGH THE AREA. MVFR CIGS ARE WIDESPREAD BEHIND THE FRONT FROM
GRR NORTH AT 7 PM WITH VFR TO THE SOUTH. ALL THE TERMINALS SOUTH
OF GRR SHOULD ALSO BECOME MVFR BY 06Z WITH WIDESPREAD IFR BY 09Z
AND WIDESPREAD LIFR LIKELY BY 12Z SUNDAY.

&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW








000
FXUS63 KGRR 010003
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
703 PM EST SAT JAN 31 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 703 PM EST SAT JAN 31 2015

FLIGHT CONDITIONS WILL DETERIORATE OVERNIGHT TO IFR AS SNOW
OVERSPREADS THE AREA FROM SOUTHWEST TO NORTHEAST. THE SNOW WILL
PERSIST ALL DAY SUNDAY AND SUNDAY NIGHT WITH WIDESPREAD LIFR
LIKELY IN SNOW AND BLOWING SNOW. ONCE THE SNOW MOVES IN LATER
TONIGHT EXPECT MODERATE ICING FROM THE SFC TO 16000 FT.

IN THE NEAR TERM THERE IS CURRENTLY A COLD FRONT SAGGING SOUTH
THROUGH THE AREA. MVFR CIGS ARE WIDESPREAD BEHIND THE FRONT FROM
GRR NORTH AT 7 PM WITH VFR TO THE SOUTH. ALL THE TERMINALS SOUTH
OF GRR SHOULD ALSO BECOME MVFR BY 06Z WITH WIDESPREAD IFR BY 09Z
AND WIDESPREAD LIFR LIKELY BY 12Z SUNDAY.

&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW







000
FXUS63 KGRR 010003
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
703 PM EST SAT JAN 31 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 703 PM EST SAT JAN 31 2015

FLIGHT CONDITIONS WILL DETERIORATE OVERNIGHT TO IFR AS SNOW
OVERSPREADS THE AREA FROM SOUTHWEST TO NORTHEAST. THE SNOW WILL
PERSIST ALL DAY SUNDAY AND SUNDAY NIGHT WITH WIDESPREAD LIFR
LIKELY IN SNOW AND BLOWING SNOW. ONCE THE SNOW MOVES IN LATER
TONIGHT EXPECT MODERATE ICING FROM THE SFC TO 16000 FT.

IN THE NEAR TERM THERE IS CURRENTLY A COLD FRONT SAGGING SOUTH
THROUGH THE AREA. MVFR CIGS ARE WIDESPREAD BEHIND THE FRONT FROM
GRR NORTH AT 7 PM WITH VFR TO THE SOUTH. ALL THE TERMINALS SOUTH
OF GRR SHOULD ALSO BECOME MVFR BY 06Z WITH WIDESPREAD IFR BY 09Z
AND WIDESPREAD LIFR LIKELY BY 12Z SUNDAY.

&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...EBW








000
FXUS63 KGRR 312154
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
454 PM EST SAT JAN 31 2015

LATEST UPDATE...
CORRECTED WATCHES/WARNINGS/ADVISORIES SECTION AT BOTTOM

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1150 AM EST SAT JAN 31 2015

VFR CONDITIONS THIS AFTERNOON WILL GRADUALLY DETERIORATE TO MVFR
THEN IFR OVERNIGHT AS LOWER CIGS AND SNOW MOVE IN. THE SNOW WILL
MOVE IN FROM WSW TO ENE AND AFFECT ALL THE TERMINALS AFTER MIDNIGHT
THROUGH DAYBREAK.

SNOW WILL GRADUALLY INCREASE IN INTENSITY FROM AROUND DAYBREAK
THROUGH 18Z SUNDAY RESULTING IN FURTHER DETERIORATION OF CONDITIONS
INTO THE LIFR FLIGHT CATEGORY AT ALL THE TERMINALS. SNOW WILL BECOME
HEAVIEST ALONG THE I-94 CORRIDOR.

WINDS WILL BE OUT OF THE WEST TO NORTHWEST THROUGH THIS EVENING
BEFORE GRADUALLY VEERING TO THE NORTHEAST OVERNIGHT. WINDS WILL
CONTINUE TO VEER SLOWLY TO THE ENE SUNDAY MORNING AND INCREASE
TO 15 TO 25 KTS.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...EBW







000
FXUS63 KGRR 312154
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
454 PM EST SAT JAN 31 2015

LATEST UPDATE...
CORRECTED WATCHES/WARNINGS/ADVISORIES SECTION AT BOTTOM

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1150 AM EST SAT JAN 31 2015

VFR CONDITIONS THIS AFTERNOON WILL GRADUALLY DETERIORATE TO MVFR
THEN IFR OVERNIGHT AS LOWER CIGS AND SNOW MOVE IN. THE SNOW WILL
MOVE IN FROM WSW TO ENE AND AFFECT ALL THE TERMINALS AFTER MIDNIGHT
THROUGH DAYBREAK.

SNOW WILL GRADUALLY INCREASE IN INTENSITY FROM AROUND DAYBREAK
THROUGH 18Z SUNDAY RESULTING IN FURTHER DETERIORATION OF CONDITIONS
INTO THE LIFR FLIGHT CATEGORY AT ALL THE TERMINALS. SNOW WILL BECOME
HEAVIEST ALONG THE I-94 CORRIDOR.

WINDS WILL BE OUT OF THE WEST TO NORTHWEST THROUGH THIS EVENING
BEFORE GRADUALLY VEERING TO THE NORTHEAST OVERNIGHT. WINDS WILL
CONTINUE TO VEER SLOWLY TO THE ENE SUNDAY MORNING AND INCREASE
TO 15 TO 25 KTS.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...EBW







000
FXUS63 KGRR 312154
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
454 PM EST SAT JAN 31 2015

LATEST UPDATE...
CORRECTED WATCHES/WARNINGS/ADVISORIES SECTION AT BOTTOM

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1150 AM EST SAT JAN 31 2015

VFR CONDITIONS THIS AFTERNOON WILL GRADUALLY DETERIORATE TO MVFR
THEN IFR OVERNIGHT AS LOWER CIGS AND SNOW MOVE IN. THE SNOW WILL
MOVE IN FROM WSW TO ENE AND AFFECT ALL THE TERMINALS AFTER MIDNIGHT
THROUGH DAYBREAK.

SNOW WILL GRADUALLY INCREASE IN INTENSITY FROM AROUND DAYBREAK
THROUGH 18Z SUNDAY RESULTING IN FURTHER DETERIORATION OF CONDITIONS
INTO THE LIFR FLIGHT CATEGORY AT ALL THE TERMINALS. SNOW WILL BECOME
HEAVIEST ALONG THE I-94 CORRIDOR.

WINDS WILL BE OUT OF THE WEST TO NORTHWEST THROUGH THIS EVENING
BEFORE GRADUALLY VEERING TO THE NORTHEAST OVERNIGHT. WINDS WILL
CONTINUE TO VEER SLOWLY TO THE ENE SUNDAY MORNING AND INCREASE
TO 15 TO 25 KTS.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...EBW








000
FXUS63 KGRR 312154
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
454 PM EST SAT JAN 31 2015

LATEST UPDATE...
CORRECTED WATCHES/WARNINGS/ADVISORIES SECTION AT BOTTOM

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1150 AM EST SAT JAN 31 2015

VFR CONDITIONS THIS AFTERNOON WILL GRADUALLY DETERIORATE TO MVFR
THEN IFR OVERNIGHT AS LOWER CIGS AND SNOW MOVE IN. THE SNOW WILL
MOVE IN FROM WSW TO ENE AND AFFECT ALL THE TERMINALS AFTER MIDNIGHT
THROUGH DAYBREAK.

SNOW WILL GRADUALLY INCREASE IN INTENSITY FROM AROUND DAYBREAK
THROUGH 18Z SUNDAY RESULTING IN FURTHER DETERIORATION OF CONDITIONS
INTO THE LIFR FLIGHT CATEGORY AT ALL THE TERMINALS. SNOW WILL BECOME
HEAVIEST ALONG THE I-94 CORRIDOR.

WINDS WILL BE OUT OF THE WEST TO NORTHWEST THROUGH THIS EVENING
BEFORE GRADUALLY VEERING TO THE NORTHEAST OVERNIGHT. WINDS WILL
CONTINUE TO VEER SLOWLY TO THE ENE SUNDAY MORNING AND INCREASE
TO 15 TO 25 KTS.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST MONDAY FOR MIZ043>046-
     050>052-056>059.

     WINTER STORM WARNING UNTIL 6 AM EST MONDAY FOR MIZ064>067-
     071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...EBW








000
FXUS63 KGRR 312001
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
301 PM EST SAT JAN 31 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.


&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

&&

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1150 AM EST SAT JAN 31 2015

VFR CONDITIONS THIS AFTERNOON WILL GRADUALLY DETERIORATE TO MVFR
THEN IFR OVERNIGHT AS LOWER CIGS AND SNOW MOVE IN. THE SNOW WILL
MOVE IN FROM WSW TO ENE AND AFFECT ALL THE TERMINALS AFTER MIDNIGHT
THROUGH DAYBREAK.

SNOW WILL GRADUALLY INCREASE IN INTENSITY FROM AROUND DAYBREAK
THROUGH 18Z SUNDAY RESULTING IN FURTHER DETERIORATION OF CONDITIONS
INTO THE LIFR FLIGHT CATEGORY AT ALL THE TERMINALS. SNOW WILL BECOME
HEAVIEST ALONG THE I-94 CORRIDOR.

WINDS WILL BE OUT OF THE WEST TO NORTHWEST THROUGH THIS EVENING
BEFORE GRADUALLY VEERING TO THE NORTHEAST OVERNIGHT. WINDS WILL
CONTINUE TO VEER SLOWLY TO THE ENE SUNDAY MORNING AND INCREASE
TO 15 TO 25 KTS.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST
     MONDAY FOR MIZ043>046-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...EBW







000
FXUS63 KGRR 312001
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
301 PM EST SAT JAN 31 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO

.SYNOPSIS...
ISSUED AT 300 PM EST SAT JAN 31 2015

SIGNIFICANT SNOWFALL IS IN STORE FOR SOUTHERN LOWER MICHIGAN AS AN
APPROACHING WINTER STORM WILL IMPACT THE AREA LATE TONIGHT AND
INTO EARLY MONDAY MORNING. GUSTY WINDS WILL LEAD TO BLOWING SNOW
AT TIMES WITH DANGEROUS TRAVEL ESPECIALLY FROM SOUTH HAVEN TO
KALAMAZOO TO JACKSON. ARCTIC AIR SETTLES IN LATER SUNDAY AND LASTS
THROUGH MUCH OF THIS UPCOMING WEEK. OCCASIONAL SNOW SHOWERS CAN BE
EXPECTED.


&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EST SAT JAN 31 2015

A WINTER STORM WARNING WILL REPLACE THE WINTER WEATHER ADVISORY
FOR THE SOUTHERN TWO ROWS OF COUNTIES...IN COORDINATION WITH IWX
AND DTX AS WELL AS THE LATEST 12Z GUIDANCE SUPPORTING A SLIGHTLY FURTHER
NORTHWARD NUDGE OF EXPECTED SIGNIFICANT SNOWFALL. OVERALL...THE
HIGHEST IMPACTS FROM THIS STORM ARE EXPECTED TO CENTER ALONG AND
SOUTH OF A LINE FROM SOUTH HAVEN TO KALAMAZOO TO JACKSON...WHERE
TOTAL SNOWFALL IS EXPECTED TO BE 10"-12" BY EARLY MONDAY
MORNING...COINCIDENT WITH GUSTY WINDS THAT WILL LEAD TO BLOWING
SNOW AND DANGEROUS TRAVEL. LESS SNOW IS EXPECTED NORTH OF THERE
BUT SEVERAL INCHES WILL FALL NONETHELESS AND TRAVEL DELAYS CAN BE
EXPECTED.

AS HAS BEEN SEEN FOR SEVERAL MODEL RUNS OVER THE LAST FEW
DAYS...TRENDS HAVE BEEN POINTING TO A SLIGHTLY FURTHER NORTH
TRACK OF THIS STORM SYSTEM. DPROG/DT ANALYSIS OF THE H850 LOW
TRACK FOR THE GFS AND ECMWF HAS REVEALED THIS TREND AND THE 12Z
NWP SUITE OVERALL CONTINUES TO SUPPORT THIS NOTION. A FEW KEY
THINGS TO MONITOR WITH THIS SYSTEM INCLUDE THE SFC LOW TRACK/H850
LOW TRENDS...MULTI- LAYER F-VECTOR CONVERGENCE (FN)...AND LOCATION
OF THE DEFORMATION ZONE. THE 12Z GFS IS A BIT OF AN OUTLIER WITH
THIS SYSTEM IN REGARD TO A DEEPER LOW...MORE FAVORABLE H850 LOW
TRACK FROM STL TO IND TO TOL AND ASSOCIATED DRY SLOT NUDGING
TOWARD THE MI/OH BORDER. THIS WOULD BRING IN FAVORABLE CONVECTIVE
INSTABILITY (-EPV) CLOSE TO OUR FAR SE FORECAST AREA NEAR JACKSON.
MULTI-LAYER F-VECTOR CONVERGENCE (FN) IS SHOWN TO BE MAXIMIZED
FIRST IN NORTHERN IL AND IN BUT THEN SHIFTING TO FAR SOUTHERN
LOWER MI...POSSIBLY OVER MUCH OF THE I-94 REGION. EVEN WITHOUT
THIS SOLUTION VERIFYING...A CONSENSUS OF 12Z MODEL GUIDANCE
SUPPORTS TOTAL PRECIP AMOUNTS OF AT LEAST 0.7"-0.8" FOR OUR
SOUTHERN ROW. WITH SNOW RATIOS AT OR SLIGHTLY ABOVE 15:1...ACCUMS
WILL LIKELY REACH THE 10"-12" RANGE FOR THE I-94 CORRIDOR (SOME
LOCALLY HIGHER AMOUNTS POSSIBLE). RAW ACCUMS FROM THE GFS APPEAR
TOO HIGH WITH THIS EVENT (14"-20" FOR SOME LOCATIONS).

REGARDING DEFORMATION ZONE PRECIP...THIS WILL NEED TO BE WATCHED
CLOSELY. RIGHT NOW THE ECMWF IS SHOWING THE GREATEST DEFORMATION
TO OCCUR ACROSS NORTHERN IL/IN/OH...POSSIBLY CREEPING UP INTO FAR
SOUTHERN LOWER MI. AS THIS WILL NOT BE A VERY DEEP LOW...NOT
EXPECTING EXCESSIVE SNOWFALL RATES IN THE DEFORMATION AREA...BUT
RATES APPROACHING 1" PER HOUR MAY BE POSSIBLE DURING THE HEIGHT OF
THE EVENT SUNDAY AFTERNOON AND EVENING. AS YOU MIGHT EXPECT...THE
12Z GFS BRINGS IN A SOLID DEFORMATION ZONE INTO OUR SE
CWA...ADDING SOME CONCERN THAT ACCUMS COULD BE HIGHER THAN
FORECAST THERE. WITH THE ECMWF SLIGHTLY FURTHER SOUTH AND WEAKER
WITH THIS FEATURE (AND OVERALL SFC LOW/H850 LOW TRACK) AS WELL AS
THE GEM (FURTHER SOUTH YET)...NOT WILLING TO GO ALL CHIPS IN ON
THE 12Z GFS SOLUTION AND WOULD PREFER A WEIGHTED BLEND OF
AVAILABLE GUIDANCE FOR THIS STORM.

THE SNOWFALL GRADIENT ACROSS SOUTHERN LOWER MICHIGAN WILL BE
READILY APPARENT AS THIS STORM COMES TO FRUITION. AMOUNTS ARE
EXPECTED TO TAPER OFF TOWARD THE I-96 CORRIDOR...WITH GENERALLY
5"-8" STILL EXPECTED FROM MKG TO GRR TO LAN...WITH 8" OR MORE
POSSIBLE FOR AREAS IN BETWEEN. AFTER LOOKING AT HI-RES MODEL
GUIDANCE (WRF-ARW...WRF-NMM...NAMDNG5) AND COMPARING TO THE
GFS...ECMWF...NAM...GEM...AND UKMET...I BELIEVE OUR FORECAST
AMOUNTS ARE RIGHT IN LINE WITH A CONSENSUS OF THESE MODEL
SOLUTIONS...WHICH ALL AGREE THAT THE HIGHEST AMOUNTS WILL BE NEAR
I-94.

WINDS WILL BE A FACTOR WITH THIS SYSTEM. GIVEN THE NE FLOW AS THE
STORM MOVES INTO THE REGION...COULD EASILY SEE WIND GUSTS
OVERACHIEVING ACROSS OUR CENTRAL AND EASTERN CWA GIVEN THE FLOW
OFF LAKE HURON AND FETCH OFF SAGINAW BAY. HAVE DECIDED TO BUMP UP
WIND GUSTS AS A RESULT. STILL GENERALLY LOOKING AT 25 TO 35 MPH
GUSTS...BUT 40 MPH IS NOT OUT OF THE QUESTION ESPECIALLY GIVEN THE
12Z GFS SOLUTION. THE BOTTOM LINE IS THERE WILL BE BLOWING AND
DRIFTING SNOW AT TIMES...AND GIVEN THE DRY NATURE OF THIS SNOW THE
VISIBILITIES WILL BE GREATLY REDUCED.

ALTHOUGH THIS STORM WILL BE WINDING DOWN EARLY MONDAY
MORNING...COULD SEE SOME LINGERING IMPACTS IN TERMS OF SNOW
COVERED ROADS AND SLICK TRAVEL FOR THE MONDAY MORNING COMMUTE...SO
CONTINUED DELAYS ARE PROBABLE. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS MAY MOVE IN DURING THE DAY BUT WILL BE SMALL POTATOES
COMPARED TO THE WINTER STORM ON SUNDAY.

&&

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 300 PM EST SAT JAN 31 2015

AN UPPER LEVEL PV ANOMALY FOLLOWED BY AN ARCTIC COLD FRONT WILL
COMBINE TO BRING SOME SNOW TUESDAY AND TUESDAY NIGHT. A SIGNIFICANT
SNOW EVENT IS NOT LIKELY BUT SOME LIGHT SNOW ACCUMULATIONS ARE
EXPECTED MAINLY FROM TUESDAY AFTERNOON THROUGH TUESDAY NIGHT.

A COLD AIRMASS WILL ADVECT IN BEHIND THAT FRONT LATE WEDNESDAY
THROUGH LATE WEEK. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY REACH THE
TEENS TO PERHAPS LOWER 20S.

LAKE EFFECT SNOW SHOWER POTENTIAL CONTINUES TO LOOK MINIMAL LATE IN
THE WEEK DUE TO THE DRY AIRMASS AND UNFAVORABLE SNOW MICROPHYSICS
AND LOW INVERSION HEIGHTS. TEMPS SHOULD MODERATE SOMEWHAT BACK TO
CLOSER TO NORMAL BY NEXT WEEKEND AS THE UPPER LEVEL PATTERN BECOMES
ZONAL AND UNAMPLIFIED.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1150 AM EST SAT JAN 31 2015

VFR CONDITIONS THIS AFTERNOON WILL GRADUALLY DETERIORATE TO MVFR
THEN IFR OVERNIGHT AS LOWER CIGS AND SNOW MOVE IN. THE SNOW WILL
MOVE IN FROM WSW TO ENE AND AFFECT ALL THE TERMINALS AFTER MIDNIGHT
THROUGH DAYBREAK.

SNOW WILL GRADUALLY INCREASE IN INTENSITY FROM AROUND DAYBREAK
THROUGH 18Z SUNDAY RESULTING IN FURTHER DETERIORATION OF CONDITIONS
INTO THE LIFR FLIGHT CATEGORY AT ALL THE TERMINALS. SNOW WILL BECOME
HEAVIEST ALONG THE I-94 CORRIDOR.

WINDS WILL BE OUT OF THE WEST TO NORTHWEST THROUGH THIS EVENING
BEFORE GRADUALLY VEERING TO THE NORTHEAST OVERNIGHT. WINDS WILL
CONTINUE TO VEER SLOWLY TO THE ENE SUNDAY MORNING AND INCREASE
TO 15 TO 25 KTS.


&&

.HYDROLOGY...
ISSUED AT 300 PM EST SAT JAN 31 2015

ICE FORMATION ON RIVERS IS THE IMMEDIATE HYDRO CONCERN. ARCTIC AIR
MOVES BACK IN ON SUNDAY WITH TEMPERATURES FALLING THROUGH THE TEENS
THROUGHOUT THE DAY. LOWS SUNDAY NIGHT AND MONDAY MORNING WILL DROP
INTO THE SINGLE DIGITS. STORM TOTAL QPF FOR THE SNOW EVENT BEGINNING
TONIGHT WILL BE AROUND A HALF INCH ALONG I-96 THROUGH MONDAY
MORNING. QPF INCREASES AS YOU MOVE SOUTH... WITH A MAX OF AROUND
THREE QUARTERS TO AN INCH OVER THE KALAMAZOO BASIN. COLD
TEMPERATURES ARE EXPECTED THROUGH THE REST OF THE WEEK.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST
     MONDAY FOR MIZ043>046-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

SYNOPSIS...HOVING
SHORT TERM...HOVING
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...EBW








000
FXUS63 KGRR 311650
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1150 AM EST SAT JAN 31 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 248 AM EST SAT JAN 31 2015

LOW PRESSURE MOVING OUT OF THE PLAINS TOWARD THE OHIO VALLEY LATER
TODAY WILL BRING A SWATH OF SNOW THROUGH SOUTHERN LOWER MICHIGAN.
SNOWFALL TOTALS FROM LATE TONIGHT THROUGH SUNDAY NIGHT COULD BE 8 TO
10 INCHES SOUTH OF I-94 WITH LESSER TOTALS THE FARTHER NORTH YOU GO.
GUSTY NORTHEAST WINDS WILL CREATE BLOWING AND DRIFTING TOO.
FINALLY...COLD WIND CHILLS SUNDAY NIGHT MAY APPROACH 10-15 BELOW
ZERO ESPECIALLY IF SKIES CAN CLEAR INLAND.

MONDAY WILL BE A VERY COLD DAY WITH HIGHS AROUND 15. ANOTHER SHOT OF
ARCTIC AIR WILL MOVED THROUGH WEDNESDAY AND THURSDAY AND HIGHS WILL
RETREAT TO THE TEENS.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 248 AM EST SAT JAN 31 2015

FORECAST CONCERNS DEAL WITH THE EVOLUTION OF A WINTER STORM THAT
WILL MOVE OVER THE OHIO VALLEY LATE TONIGHT THROUGH SUNDAY NIGHT. A
LONG DURATION SNOW EVENT IS EXPECTED FROM THIS SYSTEM.

THERE WASN/T ANY MAJOR TRACK MOVEMENT OF THE LOW WITH THE 00Z MODEL
RUNS. THE ECMWF/GFS/NAM/GEM TAKE THE LOW FROM KANSAS EAST ACROSS THE
OHIO RIVER VALLEY. THE H8 LOW TAKES A TRACK ACROSS NORTH CENTRAL
INDIANA TO TOLEDO. THIS SYSTEM HAS SOME THINGS GOING FOR IT AND ALSO
AGAINST IT. AT THE SAME TIME THE LOW IS MOVING EAST...A COLD FRONT
IS SINKING SOUTH. THIS COLD FRONT WILL MOVE THROUGH THE CWA LATE
THIS AFTERNOON AND EVENING RESULTING IN A COLD DRY FEED OF ARCTIC
AIR INTO THE CWA. THIS DRY AIR WILL BE A MITIGATING FACTOR TO SOME
DEGREE WITH THE DEVELOPING PCPN SHIELD AS IT TRIES TO MOVE
NORTHEASTWARD.

AS THE LOW MOVES OUT OF THE PLAINS A 60 KT LLJ DEVELOPS ON THE EAST
SIDE AND WILL DRAW UP SOME GULF MOISTURE. ISENTROPIC ANALYSIS ON THE
290K SFC SHOWS THE HIGHEST MIXING RATIOS OVER CENTRAL/NORTHERN
INDIANA CLOSER TO THE TRACK OF THE H8 LOW. THIS SHOULD RESULT IN THE
HEAVIEST SNOW REMAINING SOUTH OF THE CWA AND ALSO MEAN THE FAR
SOUTHERN ROW OF COUNTIES ALONG AND SOUTH OF I-94 WILL SEE THE MOST
ACCUMULATION.

OVERALL...WE WEREN`T OVERWHELMED BY THE OMEGA IN THIS SYSTEM. AND
THE DGZ IS HIGH...AROUND 12K FEET. GIVEN THE COLD AIR IN PLACE AFTER
THE FRONT MOVES THROUGH...THE TYPE OF SNOW THAT FALLS WILL BE VERY
LIGHT...AROUND A 18:1 RATIO. TEMPERATURES -15 TO -20C IN THE DGZ
SHOULD RESULT IN PLATE FORMATION RATHER THAN HIGHER ACCUMULATING
DENDRITES. THIS MAY RESULT IN LOWER VISIBILITIES AND A BIT LESS
ACCUMULATION. WINDS WILL GUST TO 25 TO 35 MPH AS THE LOW DEEPENS
OVER INDIANA. THIS WILL LEAD TO BLOWING AND DRIFTING CONDITIONS
SUNDAY ESPECIALLY OVER THE SRN COUNTIES.

QPF AND SNOW RATIO COMBINATIONS YIELD 8 TO 10 INCHES OVER THE SRN
ROW OF COUNTIES FROM 00Z TONIGHT THROUGH SUNDAY NIGHT. TOTALS FROM
HOLLAND TO GRAND RAPIDS AND LANSING LOOK LIKE THEY WILL BE IN THE 5
TO 8 INCH RANGE...WITH HIGHEST TOTALS IN THE SOUTHERN PORTION OF
THOSE COUNTIES.

THIS WILL BE A DECENT SNOWSTORM BUT PROBABLY WON/T BE CRIPPLING. AS
SUCH WE OPTED FOR A WINTER WEATHER ADVISORY VERSUS A WARNING FOR ALL
BUT
THE NORTHERN ROW OF COUNTIES AND STRATIFIED IT INTO 3 SEGMENTS BASED
ON SNOWFALL TOTALS.

LOW TEMPS SUNDAY NIGHT WILL RANGE FROM 5 BELOW TO 5 ABOVE. GUSTY
WINDS RESULTING FROM THE DEPARTING LOW WILL CREATE WIND CHILLS 10 TO
15 BELOW ZERO.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 248 AM EST SAT JAN 31 2015

STILL LOOKING AT A COMPACT AND FAST MOVING UPPER PV ANOMALY TO BRING
A ROUND OF LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY NIGHT.
CURRENTLY HAVE MONDAY NIGHT DRY...BUT THERE COULD BE LIGHT SNOW
FALLING BY THE TUESDAY MORNING COMMUTE. FOR THE ENTIRE MONDAY NIGHT
THROUGH TUESDAY NIGHT TIMEFRAME...SNOW TOTALS SHOULD BE MODEST AT
1-3 INCHES WITH 4 INCHES NEAR THE LAKESHORE.

COLD FRONT IN THE WAKE OF THE PV ANOMALY SHOULD BE THROUGH THE AREA
BY WEDNESDAY MORNING. THIS WILL BE FOLLOWED BY BELOW NORMAL
TEMPERATURES THE REST OF THE WORK WEEK WITH HIGHS THURSDAY/FRIDAY IN
THE TEENS. COLD TEMPERATURES/POOR MICROPHYSICS COMBINED WITH
SHALLOW/LIMITED MOISTURE WILL RESULT IN LITTLE IF ANY LAKE EFFECT
SNOW ACCUMULATIONS DURING THIS TIME.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1150 AM EST SAT JAN 31 2015

VFR CONDITIONS THIS AFTERNOON WILL GRADUALLY DETERIORATE TO MVFR
THEN IFR OVERNIGHT AS LOWER CIGS AND SNOW MOVE IN. THE SNOW WILL
MOVE IN FROM WSW TO ENE AND AFFECT ALL THE TERMINALS AFTER MIDNIGHT
THROUGH DAYBREAK.

SNOW WILL GRADUALLY INCREASE IN INTENSITY FROM AROUND DAYBREAK
THROUGH 18Z SUNDAY RESULTING IN FURTHER DETERIORATION OF CONDITIONS
INTO THE LIFR FLIGHT CATEGORY AT ALL THE TERMINALS. SNOW WILL BECOME
HEAVIEST ALONG THE I-94 CORRIDOR.

WINDS WILL BE OUT OF THE WEST TO NORTHWEST THROUGH THIS EVENING
BEFORE GRADUALLY VEERING TO THE NORTHEAST OVERNIGHT. WINDS WILL
CONTINUE TO VEER SLOWLY TO THE ENE SUNDAY MORNING AND INCREASE
TO 15 TO 25 KTS.

&&

.HYDROLOGY...
ISSUED AT 248 AM EST SAT JAN 31 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS
AROUND 20 SUNDAY AND AROUND 15 MONDAY WILL BE FAVORABLE FOR ICE
DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST
     MONDAY FOR MIZ043>046-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...LAURENS
HYDROLOGY...93









000
FXUS63 KGRR 311650
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1150 AM EST SAT JAN 31 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 248 AM EST SAT JAN 31 2015

LOW PRESSURE MOVING OUT OF THE PLAINS TOWARD THE OHIO VALLEY LATER
TODAY WILL BRING A SWATH OF SNOW THROUGH SOUTHERN LOWER MICHIGAN.
SNOWFALL TOTALS FROM LATE TONIGHT THROUGH SUNDAY NIGHT COULD BE 8 TO
10 INCHES SOUTH OF I-94 WITH LESSER TOTALS THE FARTHER NORTH YOU GO.
GUSTY NORTHEAST WINDS WILL CREATE BLOWING AND DRIFTING TOO.
FINALLY...COLD WIND CHILLS SUNDAY NIGHT MAY APPROACH 10-15 BELOW
ZERO ESPECIALLY IF SKIES CAN CLEAR INLAND.

MONDAY WILL BE A VERY COLD DAY WITH HIGHS AROUND 15. ANOTHER SHOT OF
ARCTIC AIR WILL MOVED THROUGH WEDNESDAY AND THURSDAY AND HIGHS WILL
RETREAT TO THE TEENS.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 248 AM EST SAT JAN 31 2015

FORECAST CONCERNS DEAL WITH THE EVOLUTION OF A WINTER STORM THAT
WILL MOVE OVER THE OHIO VALLEY LATE TONIGHT THROUGH SUNDAY NIGHT. A
LONG DURATION SNOW EVENT IS EXPECTED FROM THIS SYSTEM.

THERE WASN/T ANY MAJOR TRACK MOVEMENT OF THE LOW WITH THE 00Z MODEL
RUNS. THE ECMWF/GFS/NAM/GEM TAKE THE LOW FROM KANSAS EAST ACROSS THE
OHIO RIVER VALLEY. THE H8 LOW TAKES A TRACK ACROSS NORTH CENTRAL
INDIANA TO TOLEDO. THIS SYSTEM HAS SOME THINGS GOING FOR IT AND ALSO
AGAINST IT. AT THE SAME TIME THE LOW IS MOVING EAST...A COLD FRONT
IS SINKING SOUTH. THIS COLD FRONT WILL MOVE THROUGH THE CWA LATE
THIS AFTERNOON AND EVENING RESULTING IN A COLD DRY FEED OF ARCTIC
AIR INTO THE CWA. THIS DRY AIR WILL BE A MITIGATING FACTOR TO SOME
DEGREE WITH THE DEVELOPING PCPN SHIELD AS IT TRIES TO MOVE
NORTHEASTWARD.

AS THE LOW MOVES OUT OF THE PLAINS A 60 KT LLJ DEVELOPS ON THE EAST
SIDE AND WILL DRAW UP SOME GULF MOISTURE. ISENTROPIC ANALYSIS ON THE
290K SFC SHOWS THE HIGHEST MIXING RATIOS OVER CENTRAL/NORTHERN
INDIANA CLOSER TO THE TRACK OF THE H8 LOW. THIS SHOULD RESULT IN THE
HEAVIEST SNOW REMAINING SOUTH OF THE CWA AND ALSO MEAN THE FAR
SOUTHERN ROW OF COUNTIES ALONG AND SOUTH OF I-94 WILL SEE THE MOST
ACCUMULATION.

OVERALL...WE WEREN`T OVERWHELMED BY THE OMEGA IN THIS SYSTEM. AND
THE DGZ IS HIGH...AROUND 12K FEET. GIVEN THE COLD AIR IN PLACE AFTER
THE FRONT MOVES THROUGH...THE TYPE OF SNOW THAT FALLS WILL BE VERY
LIGHT...AROUND A 18:1 RATIO. TEMPERATURES -15 TO -20C IN THE DGZ
SHOULD RESULT IN PLATE FORMATION RATHER THAN HIGHER ACCUMULATING
DENDRITES. THIS MAY RESULT IN LOWER VISIBILITIES AND A BIT LESS
ACCUMULATION. WINDS WILL GUST TO 25 TO 35 MPH AS THE LOW DEEPENS
OVER INDIANA. THIS WILL LEAD TO BLOWING AND DRIFTING CONDITIONS
SUNDAY ESPECIALLY OVER THE SRN COUNTIES.

QPF AND SNOW RATIO COMBINATIONS YIELD 8 TO 10 INCHES OVER THE SRN
ROW OF COUNTIES FROM 00Z TONIGHT THROUGH SUNDAY NIGHT. TOTALS FROM
HOLLAND TO GRAND RAPIDS AND LANSING LOOK LIKE THEY WILL BE IN THE 5
TO 8 INCH RANGE...WITH HIGHEST TOTALS IN THE SOUTHERN PORTION OF
THOSE COUNTIES.

THIS WILL BE A DECENT SNOWSTORM BUT PROBABLY WON/T BE CRIPPLING. AS
SUCH WE OPTED FOR A WINTER WEATHER ADVISORY VERSUS A WARNING FOR ALL
BUT
THE NORTHERN ROW OF COUNTIES AND STRATIFIED IT INTO 3 SEGMENTS BASED
ON SNOWFALL TOTALS.

LOW TEMPS SUNDAY NIGHT WILL RANGE FROM 5 BELOW TO 5 ABOVE. GUSTY
WINDS RESULTING FROM THE DEPARTING LOW WILL CREATE WIND CHILLS 10 TO
15 BELOW ZERO.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 248 AM EST SAT JAN 31 2015

STILL LOOKING AT A COMPACT AND FAST MOVING UPPER PV ANOMALY TO BRING
A ROUND OF LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY NIGHT.
CURRENTLY HAVE MONDAY NIGHT DRY...BUT THERE COULD BE LIGHT SNOW
FALLING BY THE TUESDAY MORNING COMMUTE. FOR THE ENTIRE MONDAY NIGHT
THROUGH TUESDAY NIGHT TIMEFRAME...SNOW TOTALS SHOULD BE MODEST AT
1-3 INCHES WITH 4 INCHES NEAR THE LAKESHORE.

COLD FRONT IN THE WAKE OF THE PV ANOMALY SHOULD BE THROUGH THE AREA
BY WEDNESDAY MORNING. THIS WILL BE FOLLOWED BY BELOW NORMAL
TEMPERATURES THE REST OF THE WORK WEEK WITH HIGHS THURSDAY/FRIDAY IN
THE TEENS. COLD TEMPERATURES/POOR MICROPHYSICS COMBINED WITH
SHALLOW/LIMITED MOISTURE WILL RESULT IN LITTLE IF ANY LAKE EFFECT
SNOW ACCUMULATIONS DURING THIS TIME.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY)
ISSUED AT 1150 AM EST SAT JAN 31 2015

VFR CONDITIONS THIS AFTERNOON WILL GRADUALLY DETERIORATE TO MVFR
THEN IFR OVERNIGHT AS LOWER CIGS AND SNOW MOVE IN. THE SNOW WILL
MOVE IN FROM WSW TO ENE AND AFFECT ALL THE TERMINALS AFTER MIDNIGHT
THROUGH DAYBREAK.

SNOW WILL GRADUALLY INCREASE IN INTENSITY FROM AROUND DAYBREAK
THROUGH 18Z SUNDAY RESULTING IN FURTHER DETERIORATION OF CONDITIONS
INTO THE LIFR FLIGHT CATEGORY AT ALL THE TERMINALS. SNOW WILL BECOME
HEAVIEST ALONG THE I-94 CORRIDOR.

WINDS WILL BE OUT OF THE WEST TO NORTHWEST THROUGH THIS EVENING
BEFORE GRADUALLY VEERING TO THE NORTHEAST OVERNIGHT. WINDS WILL
CONTINUE TO VEER SLOWLY TO THE ENE SUNDAY MORNING AND INCREASE
TO 15 TO 25 KTS.

&&

.HYDROLOGY...
ISSUED AT 248 AM EST SAT JAN 31 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS
AROUND 20 SUNDAY AND AROUND 15 MONDAY WILL BE FAVORABLE FOR ICE
DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST
     MONDAY FOR MIZ043>046-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...LAURENS
HYDROLOGY...93








000
FXUS63 KGRR 311200
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
700 AM EST SAT JAN 31 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 248 AM EST SAT JAN 31 2015

LOW PRESSURE MOVING OUT OF THE PLAINS TOWARD THE OHIO VALLEY LATER
TODAY WILL BRING A SWATH OF SNOW THROUGH SOUTHERN LOWER MICHIGAN.
SNOWFALL TOTALS FROM LATE TONIGHT THROUGH SUNDAY NIGHT COULD BE 8 TO
10 INCHES SOUTH OF I-94 WITH LESSER TOTALS THE FARTHER NORTH YOU GO.
GUSTY NORTHEAST WINDS WILL CREATE BLOWING AND DRIFTING TOO.
FINALLY...COLD WIND CHILLS SUNDAY NIGHT MAY APPROACH 10-15 BELOW
ZERO ESPECIALLY IF SKIES CAN CLEAR INLAND.

MONDAY WILL BE A VERY COLD DAY WITH HIGHS AROUND 15. ANOTHER SHOT OF
ARCTIC AIR WILL MOVED THROUGH WEDNESDAY AND THURSDAY AND HIGHS WILL
RETREAT TO THE TEENS.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 248 AM EST SAT JAN 31 2015

FORECAST CONCERNS DEAL WITH THE EVOLUTION OF A WINTER STORM THAT
WILL MOVE OVER THE OHIO VALLEY LATE TONIGHT THROUGH SUNDAY NIGHT. A
LONG DURATION SNOW EVENT IS EXPECTED FROM THIS SYSTEM.

THERE WASN/T ANY MAJOR TRACK MOVEMENT OF THE LOW WITH THE 00Z MODEL
RUNS. THE ECMWF/GFS/NAM/GEM TAKE THE LOW FROM KANSAS EAST ACROSS THE
OHIO RIVER VALLEY. THE H8 LOW TAKES A TRACK ACROSS NORTH CENTRAL
INDIANA TO TOLEDO. THIS SYSTEM HAS SOME THINGS GOING FOR IT AND ALSO
AGAINST IT. AT THE SAME TIME THE LOW IS MOVING EAST...A COLD FRONT
IS SINKING SOUTH. THIS COLD FRONT WILL MOVE THROUGH THE CWA LATE
THIS AFTERNOON AND EVENING RESULTING IN A COLD DRY FEED OF ARCTIC
AIR INTO THE CWA. THIS DRY AIR WILL BE A MITIGATING FACTOR TO SOME
DEGREE WITH THE DEVELOPING PCPN SHIELD AS IT TRIES TO MOVE
NORTHEASTWARD.

AS THE LOW MOVES OUT OF THE PLAINS A 60 KT LLJ DEVELOPS ON THE EAST
SIDE AND WILL DRAW UP SOME GULF MOISTURE. ISENTROPIC ANALYSIS ON THE
290K SFC SHOWS THE HIGHEST MIXING RATIOS OVER CENTRAL/NORTHERN
INDIANA CLOSER TO THE TRACK OF THE H8 LOW. THIS SHOULD RESULT IN THE
HEAVIEST SNOW REMAINING SOUTH OF THE CWA AND ALSO MEAN THE FAR
SOUTHERN ROW OF COUNTIES ALONG AND SOUTH OF I-94 WILL SEE THE MOST
ACCUMULATION.

OVERALL...WE WEREN`T OVERWHELMED BY THE OMEGA IN THIS SYSTEM. AND
THE DGZ IS HIGH...AROUND 12K FEET. GIVEN THE COLD AIR IN PLACE AFTER
THE FRONT MOVES THROUGH...THE TYPE OF SNOW THAT FALLS WILL BE VERY
LIGHT...AROUND A 18:1 RATIO. TEMPERATURES -15 TO -20C IN THE DGZ
SHOULD RESULT IN PLATE FORMATION RATHER THAN HIGHER ACCUMULATING
DENDRITES. THIS MAY RESULT IN LOWER VISIBILITIES AND A BIT LESS
ACCUMULATION. WINDS WILL GUST TO 25 TO 35 MPH AS THE LOW DEEPENS
OVER INDIANA. THIS WILL LEAD TO BLOWING AND DRIFTING CONDITIONS
SUNDAY ESPECIALLY OVER THE SRN COUNTIES.

QPF AND SNOW RATIO COMBINATIONS YIELD 8 TO 10 INCHES OVER THE SRN
ROW OF COUNTIES FROM 00Z TONIGHT THROUGH SUNDAY NIGHT. TOTALS FROM
HOLLAND TO GRAND RAPIDS AND LANSING LOOK LIKE THEY WILL BE IN THE 5
TO 8 INCH RANGE...WITH HIGHEST TOTALS IN THE SOUTHERN PORTION OF
THOSE COUNTIES.

THIS WILL BE A DECENT SNOWSTORM BUT PROBABLY WON/T BE CRIPPLING. AS
SUCH WE OPTED FOR A WINTER WEATHER ADVISORY VERSUS A WARNING FOR ALL
BUT
THE NORTHERN ROW OF COUNTIES AND STRATIFIED IT INTO 3 SEGMENTS BASED
ON SNOWFALL TOTALS.

LOW TEMPS SUNDAY NIGHT WILL RANGE FROM 5 BELOW TO 5 ABOVE. GUSTY
WINDS RESULTING FROM THE DEPARTING LOW WILL CREATE WIND CHILLS 10 TO
15 BELOW ZERO.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 248 AM EST SAT JAN 31 2015

STILL LOOKING AT A COMPACT AND FAST MOVING UPPER PV ANOMALY TO BRING
A ROUND OF LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY NIGHT.
CURRENTLY HAVE MONDAY NIGHT DRY...BUT THERE COULD BE LIGHT SNOW
FALLING BY THE TUESDAY MORNING COMMUTE. FOR THE ENTIRE MONDAY NIGHT
THROUGH TUESDAY NIGHT TIMEFRAME...SNOW TOTALS SHOULD BE MODEST AT
1-3 INCHES WITH 4 INCHES NEAR THE LAKESHORE.

COLD FRONT IN THE WAKE OF THE PV ANOMALY SHOULD BE THROUGH THE AREA
BY WEDNESDAY MORNING. THIS WILL BE FOLLOWED BY BELOW NORMAL
TEMPERATURES THE REST OF THE WORK WEEK WITH HIGHS THURSDAY/FRIDAY IN
THE TEENS. COLD TEMPERATURES/POOR MICROPHYSICS COMBINED WITH
SHALLOW/LIMITED MOISTURE WILL RESULT IN LITTLE IF ANY LAKE EFFECT
SNOW ACCUMULATIONS DURING THIS TIME.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 700 AM EST SAT JAN 31 2015

MAIN CHALLENGE THROUGH 18Z IS MVFR CEILINGS. HAVE SEEN OCCASIONAL
BKN025 AT MANY OF THE TERMINALS THIS MORNING. DO NOT EXPECT CIGS
TO GET BELOW 2000FT...SO NO FUEL ALTERNATE CONCERNS. EXPECT A MORE
SOLID COVERAGE OF 2500-4000 FT CIGS LATER TODAY.

EXPECT FUEL ALT CIGS AT MANY TERMINALS AFTER 00Z WITH SNOW MOVING
INTO THE AREA. HAVE NOT MENTIONED YET IN THE TAFS THIS FAR OUT...
BUT PROSPECTS FOR IFR CIGS/VSBYS INCREASE SIGNIFICANTLY AFTER 06Z
SUNDAY. SUBSEQUENT TAFS WILL TRY TO ADDRESS THIS MORE SPECIFICALLY.

&&

.HYDROLOGY...
ISSUED AT 248 AM EST SAT JAN 31 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS
AROUND 20 SUNDAY AND AROUND 15 MONDAY WILL BE FAVORABLE FOR ICE
DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST
     MONDAY FOR MIZ043>046-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...93







000
FXUS63 KGRR 310748
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
248 AM EST SAT JAN 31 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO

.SYNOPSIS...
ISSUED AT 248 AM EST SAT JAN 31 2015

LOW PRESSURE MOVING OUT OF THE PLAINS TOWARD THE OHIO VALLEY LATER
TODAY WILL BRING A SWATH OF SNOW THROUGH SOUTHERN LOWER MICHIGAN.
SNOWFALL TOTALS FROM LATE TONIGHT THROUGH SUNDAY NIGHT COULD BE 8 TO
10 INCHES SOUTH OF I-94 WITH LESSER TOTALS THE FARTHER NORTH YOU GO.
GUSTY NORTHEAST WINDS WILL CREATE BLOWING AND DRIFTING TOO.
FINALLY...COLD WIND CHILLS SUNDAY NIGHT MAY APPROACH 10-15 BELOW
ZERO ESPECIALLY IF SKIES CAN CLEAR INLAND.

MONDAY WILL BE A VERY COLD DAY WITH HIGHS AROUND 15. ANOTHER SHOT OF
ARCTIC AIR WILL MOVED THROUGH WEDNESDAY AND THURSDAY AND HIGHS WILL
RETREAT TO THE TEENS.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 248 AM EST SAT JAN 31 2015

FORECAST CONCERNS DEAL WITH THE EVOLUTION OF A WINTER STORM THAT
WILL MOVE OVER THE OHIO VALLEY LATE TONIGHT THROUGH SUNDAY NIGHT. A
LONG DURATION SNOW EVENT IS EXPECTED FROM THIS SYSTEM.

THERE WASN/T ANY MAJOR TRACK MOVEMENT OF THE LOW WITH THE 00Z MODEL
RUNS. THE ECMWF/GFS/NAM/GEM TAKE THE LOW FROM KANSAS EAST ACROSS THE
OHIO RIVER VALLEY. THE H8 LOW TAKES A TRACK ACROSS NORTH CENTRAL
INDIANA TO TOLEDO. THIS SYSTEM HAS SOME THINGS GOING FOR IT AND ALSO
AGAINST IT. AT THE SAME TIME THE LOW IS MOVING EAST...A COLD FRONT
IS SINKING SOUTH. THIS COLD FRONT WILL MOVE THROUGH THE CWA LATE
THIS AFTERNOON AND EVENING RESULTING IN A COLD DRY FEED OF ARCTIC
AIR INTO THE CWA. THIS DRY AIR WILL BE A MITIGATING FACTOR TO SOME
DEGREE WITH THE DEVELOPING PCPN SHIELD AS IT TRIES TO MOVE
NORTHEASTWARD.

AS THE LOW MOVES OUT OF THE PLAINS A 60 KT LLJ DEVELOPS ON THE EAST
SIDE AND WILL DRAW UP SOME GULF MOISTURE. ISENTROPIC ANALYSIS ON THE
290K SFC SHOWS THE HIGHEST MIXING RATIOS OVER CENTRAL/NORTHERN
INDIANA CLOSER TO THE TRACK OF THE H8 LOW. THIS SHOULD RESULT IN THE
HEAVIEST SNOW REMAINING SOUTH OF THE CWA AND ALSO MEAN THE FAR
SOUTHERN ROW OF COUNTIES ALONG AND SOUTH OF I-94 WILL SEE THE MOST
ACCUMULATION.

OVERALL...WE WEREN`T OVERWHELMED BY THE OMEGA IN THIS SYSTEM. AND
THE DGZ IS HIGH...AROUND 12K FEET. GIVEN THE COLD AIR IN PLACE AFTER
THE FRONT MOVES THROUGH...THE TYPE OF SNOW THAT FALLS WILL BE VERY
LIGHT...AROUND A 18:1 RATIO. TEMPERATURES -15 TO -20C IN THE DGZ
SHOULD RESULT IN PLATE FORMATION RATHER THAN HIGHER ACCUMULATING
DENDRITES. THIS MAY RESULT IN LOWER VISIBILITIES AND A BIT LESS
ACCUMULATION. WINDS WILL GUST TO 25 TO 35 MPH AS THE LOW DEEPENS
OVER INDIANA. THIS WILL LEAD TO BLOWING AND DRIFTING CONDITIONS
SUNDAY ESPECIALLY OVER THE SRN COUNTIES.

QPF AND SNOW RATIO COMBINATIONS YIELD 8 TO 10 INCHES OVER THE SRN
ROW OF COUNTIES FROM 00Z TONIGHT THROUGH SUNDAY NIGHT. TOTALS FROM
HOLLAND TO GRAND RAPIDS AND LANSING LOOK LIKE THEY WILL BE IN THE 5
TO 8 INCH RANGE...WITH HIGHEST TOTALS IN THE SOUTHERN PORTION OF
THOSE COUNTIES.

THIS WILL BE A DECENT SNOWSTORM BUT PROBABLY WON/T BE CRIPPLING. AS
SUCH WE OPTED FOR A WINTER WEATHER ADVISORY VERSUS A WARNING FOR ALL
BUT
THE NORTHERN ROW OF COUNTIES AND STRATIFIED IT INTO 3 SEGMENTS BASED
ON SNOWFALL TOTALS.

LOW TEMPS SUNDAY NIGHT WILL RANGE FROM 5 BELOW TO 5 ABOVE. GUSTY
WINDS RESULTING FROM THE DEPARTING LOW WILL CREATE WIND CHILLS 10 TO
15 BELOW ZERO.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 248 AM EST SAT JAN 31 2015

STILL LOOKING AT A COMPACT AND FAST MOVING UPPER PV ANOMALY TO BRING
A ROUND OF LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY NIGHT.
CURRENTLY HAVE MONDAY NIGHT DRY...BUT THERE COULD BE LIGHT SNOW
FALLING BY THE TUESDAY MORNING COMMUTE. FOR THE ENTIRE MONDAY NIGHT
THROUGH TUESDAY NIGHT TIMEFRAME...SNOW TOTALS SHOULD BE MODEST AT
1-3 INCHES WITH 4 INCHES NEAR THE LAKESHORE.

COLD FRONT IN THE WAKE OF THE PV ANOMALY SHOULD BE THROUGH THE AREA
BY WEDNESDAY MORNING. THIS WILL BE FOLLOWED BY BELOW NORMAL
TEMPERATURES THE REST OF THE WORK WEEK WITH HIGHS THURSDAY/FRIDAY IN
THE TEENS. COLD TEMPERATURES/POOR MICROPHYSICS COMBINED WITH
SHALLOW/LIMITED MOISTURE WILL RESULT IN LITTLE IF ANY LAKE EFFECT
SNOW ACCUMULATIONS DURING THIS TIME.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1158 PM EST FRI JAN 30 2015

AREAS OF MVFR CLOUDS FROM EARLIER HAVE DISSIPATED FOR THE MOST
PART WITH THE EXCEPTION OF THE LAKE MI SHORELINE INCLUDING MKG.
THESE CLOUDS WILL PROBABLY PERSIST MUCH OF TONIGHT AND SATURDAY
AT MKG GIVEN THAT THE LOW LEVEL FLOW IS OUT OF THE SOUTHWEST OFF
LK MI... AND MAY ALSO IMPACT GRR.

OTHERWISE VFR CONDITIONS ARE EXPECTED SOUTH AND EAST OF GRR
TONIGHT AND SATURDAY MORNING WITH SCT-BKN CLOUD BASES MAINLY
ABOVE 8000 FT. SOME LOWER CIGS OF 2500-4000 FT SHOULD SPREAD FROM
NORTHWEST TO SOUTHEAST SATURDAY AFTERNOON AS A COLD FRONT
APPROACHES.

FLIGHT CONDITIONS AT ALL THE TERMINALS WILL CONTINUE TO TREND
DOWNWARD AFTER 00Z SUNDAY AS THE FRONTAL BOUNDARY SLIPS SLOWLY
SOUTH THROUGH THE AREA... WITH MVFR BECOMING MORE WIDESPREAD WITH
TIME. THE OUTLOOK BEYOND 06Z SUNDAY IS FOR WIDESPREAD IFR TO
DEVELOP AS SNOW OVERSPREADS THE AREA.


&&

.HYDROLOGY...
ISSUED AT 248 AM EST SAT JAN 31 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS
AROUND 20 SUNDAY AND AROUND 15 MONDAY WILL BE FAVORABLE FOR ICE
DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST
     MONDAY FOR MIZ043>046-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...MEADE
HYDROLOGY...93










000
FXUS63 KGRR 310457
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1157 PM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 328 PM EST FRI JAN 30 2015

LOW PRESSURE WILL BRING SOME SNOW ON SUNDAY WITH THE HIGHEST
AMOUNTS ACROSS FAR SOUTHERN LOWER MICHIGAN NEAR THE INDIANA
BORDER. VERY COLD WEATHER IS EXPECTED MONDAY WITH MORE SNOW
POSSIBLE TUESDAY NIGHT AND WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM EST FRI JAN 30 2015

THE STORM ON SUNDAY IS THE MAIN FORECAST PROBLEM IN THE NEAR TERM.
12Z MODEL GUIDANCE CONTINUES TO SHOW THE POTENTIAL FOR 4 OR MORE
INCHES OF SNOW ACROSS THE I-94 CORRIDOR BETWEEN SATURDAY NIGHT AND
SUNDAY NIGHT. HELD OFF ON HEADLINES FOR NOW BASED ON UNCERTAINTY
THAT THE RECENT MORE NORTHERLY JOG WILL LAST...ALTHOUGH THE CURRENT
TREND IS DEFINITELY IN THAT DIRECTION.

THE SYNOPTIC SET UP IS SIMILAR TO LAST SUNDAY WITH A COLD AND DRY
AIR MASS TO THE NORTH AND A LOW PASSING THROUGH THE OHIO VALLEY.
ONCE AGAIN WE EXPECT A SHARP SNOWFALL GRADIENT AS MESOSCALE BANDS
WILL ALIGN EAST TO WEST ACROSS THE SOUTHERN FORECAST AREA IN AREA OF
MID LEVEL F-GEN FORCING. WE BUMPED UP THE POPS AND QPF FOR SATURDAY
NIGHT THROUGH SUNDAY NIGHT WITH THE BULK OF THE SNOW FALLING SUNDAY
MORNING. SOME INCH AN HOUR RATES ARE POSSIBLE ACROSS THE FAR SOUTH
SUNDAY MORNING INTO THE AFTERNOON.

THE LOW IS CURRENTLY GATHERING STRENGTH ACROSS THE SOUTHWEST CONUS
AND IS BEING FED BY A DEEP PLUME OF TROPICAL MOISTURE FROM THE
EASTERN PACIFIC. THE LOW WILL ALSO GET GOOD GULF OF MEXICO INFLOW AS
IT MOVES EAST. MEANWHILE...EASTERLY FLOW DEVELOPS AHEAD OF THE
SYSTEM AND A MATURE CYCLONE WITH WARM AND COLD CONVEYOR BELTS TRACKS
ACROSS THE OHIO VALLEY WITH 12Z MODEL GUIDANCE SHOWING ENOUGH QPF TO
COME CLOSE TO WARNING CRITERIA ACROSS THE FAR SOUTH. SNOW TOTALS
WILL PROBABLY END UP 20 TO 1 OR GREATER GIVEN THE COLD AIR IN PLACE
DURING THIS EVENT.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 328 PM EST FRI JAN 30 2015

VERY COLD WEATHER WILL CONTINUE MONDAY WITH POTENTIAL FOR SINGLE
DIGIT BELOW TO ABOVE ZERO READINGS EARLY MONDAY MORNING. MAX TEMPS
WILL ONLY REACH THE TEENS MONDAY IN SPITE OF SOME SUN WITH HIGH
PRESSURE IN CONTROL. THE NEXT LOW PRESSURE SYSTEM AND PV ANOMALY
WILL BRING POTENTIAL FOR LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY
NIGHT.

THE COLD FRONT SHOULD BE THROUGH OUR AREA BY WEDNESDAY MORNING WITH
ANOTHER INTRUSION OF ARCTIC AIR AND BELOW NORMAL TEMPS FROM
WEDNESDAY NIGHT THROUGH LATE WEEK. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE LATE IN THE WEEK.

OVERALL THOUGH THE SETUP DOES NOT LOOK FAVORABLE FOR LAKE EFFECT
SNOW OF ANY SIGNIFICANCE LATE IN THE WEEK DUE TO THE VERY DRY ARCTIC
AIRMASS AND DRY FCST SOUNDINGS THURSDAY/FRIDAY AS WELL AS VERY LOW
INVERSION HEIGHTS BY THEN. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY
REACH THE TEENS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1158 PM EST FRI JAN 30 2015

AREAS OF MVFR CLOUDS FROM EARLIER HAVE DISSIPATED FOR THE MOST
PART WITH THE EXCEPTION OF THE LAKE MI SHORELINE INCLUDING MKG.
THESE CLOUDS WILL PROBABLY PERSIST MUCH OF TONIGHT AND SATURDAY
AT MKG GIVEN THAT THE LOW LEVEL FLOW IS OUT OF THE SOUTHWEST OFF
LK MI... AND MAY ALSO IMPACT GRR.

OTHERWISE VFR CONDITIONS ARE EXPECTED SOUTH AND EAST OF GRR
TONIGHT AND SATURDAY MORNING WITH SCT-BKN CLOUD BASES MAINLY
ABOVE 8000 FT. SOME LOWER CIGS OF 2500-4000 FT SHOULD SPREAD FROM
NORTHWEST TO SOUTHEAST SATURDAY AFTERNOON AS A COLD FRONT
APPROACHES.

FLIGHT CONDITIONS AT ALL THE TERMINALS WILL CONTINUE TO TREND
DOWNWARD AFTER 00Z SUNDAY AS THE FRONTAL BOUNDARY SLIPS SLOWLY
SOUTH THROUGH THE AREA... WITH MVFR BECOMING MORE WIDESPREAD WITH
TIME. THE OUTLOOK BEYOND 06Z SUNDAY IS FOR WIDESPREAD IFR TO
DEVELOP AS SNOW OVERSPREADS THE AREA.

&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS AROUND
20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE FOR ICE
DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...93








000
FXUS63 KGRR 310457
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1157 PM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 328 PM EST FRI JAN 30 2015

LOW PRESSURE WILL BRING SOME SNOW ON SUNDAY WITH THE HIGHEST
AMOUNTS ACROSS FAR SOUTHERN LOWER MICHIGAN NEAR THE INDIANA
BORDER. VERY COLD WEATHER IS EXPECTED MONDAY WITH MORE SNOW
POSSIBLE TUESDAY NIGHT AND WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM EST FRI JAN 30 2015

THE STORM ON SUNDAY IS THE MAIN FORECAST PROBLEM IN THE NEAR TERM.
12Z MODEL GUIDANCE CONTINUES TO SHOW THE POTENTIAL FOR 4 OR MORE
INCHES OF SNOW ACROSS THE I-94 CORRIDOR BETWEEN SATURDAY NIGHT AND
SUNDAY NIGHT. HELD OFF ON HEADLINES FOR NOW BASED ON UNCERTAINTY
THAT THE RECENT MORE NORTHERLY JOG WILL LAST...ALTHOUGH THE CURRENT
TREND IS DEFINITELY IN THAT DIRECTION.

THE SYNOPTIC SET UP IS SIMILAR TO LAST SUNDAY WITH A COLD AND DRY
AIR MASS TO THE NORTH AND A LOW PASSING THROUGH THE OHIO VALLEY.
ONCE AGAIN WE EXPECT A SHARP SNOWFALL GRADIENT AS MESOSCALE BANDS
WILL ALIGN EAST TO WEST ACROSS THE SOUTHERN FORECAST AREA IN AREA OF
MID LEVEL F-GEN FORCING. WE BUMPED UP THE POPS AND QPF FOR SATURDAY
NIGHT THROUGH SUNDAY NIGHT WITH THE BULK OF THE SNOW FALLING SUNDAY
MORNING. SOME INCH AN HOUR RATES ARE POSSIBLE ACROSS THE FAR SOUTH
SUNDAY MORNING INTO THE AFTERNOON.

THE LOW IS CURRENTLY GATHERING STRENGTH ACROSS THE SOUTHWEST CONUS
AND IS BEING FED BY A DEEP PLUME OF TROPICAL MOISTURE FROM THE
EASTERN PACIFIC. THE LOW WILL ALSO GET GOOD GULF OF MEXICO INFLOW AS
IT MOVES EAST. MEANWHILE...EASTERLY FLOW DEVELOPS AHEAD OF THE
SYSTEM AND A MATURE CYCLONE WITH WARM AND COLD CONVEYOR BELTS TRACKS
ACROSS THE OHIO VALLEY WITH 12Z MODEL GUIDANCE SHOWING ENOUGH QPF TO
COME CLOSE TO WARNING CRITERIA ACROSS THE FAR SOUTH. SNOW TOTALS
WILL PROBABLY END UP 20 TO 1 OR GREATER GIVEN THE COLD AIR IN PLACE
DURING THIS EVENT.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 328 PM EST FRI JAN 30 2015

VERY COLD WEATHER WILL CONTINUE MONDAY WITH POTENTIAL FOR SINGLE
DIGIT BELOW TO ABOVE ZERO READINGS EARLY MONDAY MORNING. MAX TEMPS
WILL ONLY REACH THE TEENS MONDAY IN SPITE OF SOME SUN WITH HIGH
PRESSURE IN CONTROL. THE NEXT LOW PRESSURE SYSTEM AND PV ANOMALY
WILL BRING POTENTIAL FOR LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY
NIGHT.

THE COLD FRONT SHOULD BE THROUGH OUR AREA BY WEDNESDAY MORNING WITH
ANOTHER INTRUSION OF ARCTIC AIR AND BELOW NORMAL TEMPS FROM
WEDNESDAY NIGHT THROUGH LATE WEEK. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE LATE IN THE WEEK.

OVERALL THOUGH THE SETUP DOES NOT LOOK FAVORABLE FOR LAKE EFFECT
SNOW OF ANY SIGNIFICANCE LATE IN THE WEEK DUE TO THE VERY DRY ARCTIC
AIRMASS AND DRY FCST SOUNDINGS THURSDAY/FRIDAY AS WELL AS VERY LOW
INVERSION HEIGHTS BY THEN. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY
REACH THE TEENS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1158 PM EST FRI JAN 30 2015

AREAS OF MVFR CLOUDS FROM EARLIER HAVE DISSIPATED FOR THE MOST
PART WITH THE EXCEPTION OF THE LAKE MI SHORELINE INCLUDING MKG.
THESE CLOUDS WILL PROBABLY PERSIST MUCH OF TONIGHT AND SATURDAY
AT MKG GIVEN THAT THE LOW LEVEL FLOW IS OUT OF THE SOUTHWEST OFF
LK MI... AND MAY ALSO IMPACT GRR.

OTHERWISE VFR CONDITIONS ARE EXPECTED SOUTH AND EAST OF GRR
TONIGHT AND SATURDAY MORNING WITH SCT-BKN CLOUD BASES MAINLY
ABOVE 8000 FT. SOME LOWER CIGS OF 2500-4000 FT SHOULD SPREAD FROM
NORTHWEST TO SOUTHEAST SATURDAY AFTERNOON AS A COLD FRONT
APPROACHES.

FLIGHT CONDITIONS AT ALL THE TERMINALS WILL CONTINUE TO TREND
DOWNWARD AFTER 00Z SUNDAY AS THE FRONTAL BOUNDARY SLIPS SLOWLY
SOUTH THROUGH THE AREA... WITH MVFR BECOMING MORE WIDESPREAD WITH
TIME. THE OUTLOOK BEYOND 06Z SUNDAY IS FOR WIDESPREAD IFR TO
DEVELOP AS SNOW OVERSPREADS THE AREA.

&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS AROUND
20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE FOR ICE
DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...93







000
FXUS63 KGRR 310005
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
705 PM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 328 PM EST FRI JAN 30 2015

LOW PRESSURE WILL BRING SOME SNOW ON SUNDAY WITH THE HIGHEST
AMOUNTS ACROSS FAR SOUTHERN LOWER MICHIGAN NEAR THE INDIANA
BORDER. VERY COLD WEATHER IS EXPECTED MONDAY WITH MORE SNOW
POSSIBLE TUESDAY NIGHT AND WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM EST FRI JAN 30 2015

THE STORM ON SUNDAY IS THE MAIN FORECAST PROBLEM IN THE NEAR TERM.
12Z MODEL GUIDANCE CONTINUES TO SHOW THE POTENTIAL FOR 4 OR MORE
INCHES OF SNOW ACROSS THE I-94 CORRIDOR BETWEEN SATURDAY NIGHT AND
SUNDAY NIGHT. HELD OFF ON HEADLINES FOR NOW BASED ON UNCERTAINTY
THAT THE RECENT MORE NORTHERLY JOG WILL LAST...ALTHOUGH THE CURRENT
TREND IS DEFINITELY IN THAT DIRECTION.

THE SYNOPTIC SET UP IS SIMILAR TO LAST SUNDAY WITH A COLD AND DRY
AIR MASS TO THE NORTH AND A LOW PASSING THROUGH THE OHIO VALLEY.
ONCE AGAIN WE EXPECT A SHARP SNOWFALL GRADIENT AS MESOSCALE BANDS
WILL ALIGN EAST TO WEST ACROSS THE SOUTHERN FORECAST AREA IN AREA OF
MID LEVEL F-GEN FORCING. WE BUMPED UP THE POPS AND QPF FOR SATURDAY
NIGHT THROUGH SUNDAY NIGHT WITH THE BULK OF THE SNOW FALLING SUNDAY
MORNING. SOME INCH AN HOUR RATES ARE POSSIBLE ACROSS THE FAR SOUTH
SUNDAY MORNING INTO THE AFTERNOON.

THE LOW IS CURRENTLY GATHERING STRENGTH ACROSS THE SOUTHWEST CONUS
AND IS BEING FED BY A DEEP PLUME OF TROPICAL MOISTURE FROM THE
EASTERN PACIFIC. THE LOW WILL ALSO GET GOOD GULF OF MEXICO INFLOW AS
IT MOVES EAST. MEANWHILE...EASTERLY FLOW DEVELOPS AHEAD OF THE
SYSTEM AND A MATURE CYCLONE WITH WARM AND COLD CONVEYOR BELTS TRACKS
ACROSS THE OHIO VALLEY WITH 12Z MODEL GUIDANCE SHOWING ENOUGH QPF TO
COME CLOSE TO WARNING CRITERIA ACROSS THE FAR SOUTH. SNOW TOTALS
WILL PROBABLY END UP 20 TO 1 OR GREATER GIVEN THE COLD AIR IN PLACE
DURING THIS EVENT.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 328 PM EST FRI JAN 30 2015

VERY COLD WEATHER WILL CONTINUE MONDAY WITH POTENTIAL FOR SINGLE
DIGIT BELOW TO ABOVE ZERO READINGS EARLY MONDAY MORNING. MAX TEMPS
WILL ONLY REACH THE TEENS MONDAY IN SPITE OF SOME SUN WITH HIGH
PRESSURE IN CONTROL. THE NEXT LOW PRESSURE SYSTEM AND PV ANOMALY
WILL BRING POTENTIAL FOR LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY
NIGHT.

THE COLD FRONT SHOULD BE THROUGH OUR AREA BY WEDNESDAY MORNING WITH
ANOTHER INTRUSION OF ARCTIC AIR AND BELOW NORMAL TEMPS FROM
WEDNESDAY NIGHT THROUGH LATE WEEK. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE LATE IN THE WEEK.

OVERALL THOUGH THE SETUP DOES NOT LOOK FAVORABLE FOR LAKE EFFECT
SNOW OF ANY SIGNIFICANCE LATE IN THE WEEK DUE TO THE VERY DRY ARCTIC
AIRMASS AND DRY FCST SOUNDINGS THURSDAY/FRIDAY AS WELL AS VERY LOW
INVERSION HEIGHTS BY THEN. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY
REACH THE TEENS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 700 PM EST FRI JAN 30 2015

LOW CONFIDENCE WITH RESPECT TO EXTENT/COVERAGE OF MVFR CLOUDS
TONIGHT AND SATURDAY. AT 7 PM FRIDAY THERE IS AN AREA OF LAKE
EFFECT CLOUDS WITH BASES AROUND 2500 FT FROM MKG/BIV TO AZO. THIS
AREA OF CLOUDS IS MOVING TO THE EAST NOW THAT THE LOW LEVEL FLOW
IS BACKING. AS THE CLOUDS CONTINUE TO THE EAST... BTL AND GRR MAY
BECOME MVFR FOR AWHILE THIS EVENING.

NOT SURE IF THE MVFR CLOUDS WILL EVER COMPLETELY GO AWAY LATER TONIGHT
AND SATURDAY. IN FACT THE NAM GUIDANCE IS SUGGESTING RATHER
WIDESPREAD COVERAGE OF LOW CLOUDS DEVELOPING ON SATURDAY...
ESPECIALLY IN THE AFTERNOON AS DEW POINTS RISE IN THE SOUTHWEST
FLOW LEVEL FLOW OF AROUND 10-15 KTS AHEAD OF THE APPROACHING SFC COLD
FRONT. SINCE THE NAM TYPICALLY DOES WELL WITH LOW LEVEL MOISTURE
TRENDS... WILL FEATURE MVFR CLOUDS AT ALL THE TERMINALS AFTER 18Z
SATURDAY. BEFORE THAT...A MIX OF MVFR/VFR IS EXPECTED AND
DEPENDENT ON THE BEHAVIOR OF THE EXISTING AFOREMENTIONED LAKE
CLOUDS.

&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS AROUND
20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE FOR ICE
DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...MEADE
HYDROLOGY...93







000
FXUS63 KGRR 302028
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
328 PM EST FRI JAN 30 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM

.SYNOPSIS...
ISSUED AT 328 PM EST FRI JAN 30 2015

LOW PRESSURE WILL BRING SOME SNOW ON SUNDAY WITH THE HIGHEST
AMOUNTS ACROSS FAR SOUTHERN LOWER MICHIGAN NEAR THE INDIANA
BORDER. VERY COLD WEATHER IS EXPECTED MONDAY WITH MORE SNOW
POSSIBLE TUESDAY NIGHT AND WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM EST FRI JAN 30 2015

THE STORM ON SUNDAY IS THE MAIN FORECAST PROBLEM IN THE NEAR TERM.
12Z MODEL GUIDANCE CONTINUES TO SHOW THE POTENTIAL FOR 4 OR MORE
INCHES OF SNOW ACROSS THE I-94 CORRIDOR BETWEEN SATURDAY NIGHT AND
SUNDAY NIGHT. HELD OFF ON HEADLINES FOR NOW BASED ON UNCERTAINTY
THAT THE RECENT MORE NORTHERLY JOG WILL LAST...ALTHOUGH THE CURRENT
TREND IS DEFINITELY IN THAT DIRECTION.

THE SYNOPTIC SET UP IS SIMILAR TO LAST SUNDAY WITH A COLD AND DRY
AIR MASS TO THE NORTH AND A LOW PASSING THROUGH THE OHIO VALLEY.
ONCE AGAIN WE EXPECT A SHARP SNOWFALL GRADIENT AS MESOSCALE BANDS
WILL ALIGN EAST TO WEST ACROSS THE SOUTHERN FORECAST AREA IN AREA OF
MID LEVEL F-GEN FORCING. WE BUMPED UP THE POPS AND QPF FOR SATURDAY
NIGHT THROUGH SUNDAY NIGHT WITH THE BULK OF THE SNOW FALLING SUNDAY
MORNING. SOME INCH AN HOUR RATES ARE POSSIBLE ACROSS THE FAR SOUTH
SUNDAY MORNING INTO THE AFTERNOON.

THE LOW IS CURRENTLY GATHERING STRENGTH ACROSS THE SOUTHWEST CONUS
AND IS BEING FED BY A DEEP PLUME OF TROPICAL MOISTURE FROM THE
EASTERN PACIFIC. THE LOW WILL ALSO GET GOOD GULF OF MEXICO INFLOW AS
IT MOVES EAST. MEANWHILE...EASTERLY FLOW DEVELOPS AHEAD OF THE
SYSTEM AND A MATURE CYCLONE WITH WARM AND COLD CONVEYOR BELTS TRACKS
ACROSS THE OHIO VALLEY WITH 12Z MODEL GUIDANCE SHOWING ENOUGH QPF TO
COME CLOSE TO WARNING CRITERIA ACROSS THE FAR SOUTH. SNOW TOTALS
WILL PROBABLY END UP 20 TO 1 OR GREATER GIVEN THE COLD AIR IN PLACE
DURING THIS EVENT.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 328 PM EST FRI JAN 30 2015

VERY COLD WEATHER WILL CONTINUE MONDAY WITH POTENTIAL FOR SINGLE
DIGIT BELOW TO ABOVE ZERO READINGS EARLY MONDAY MORNING. MAX TEMPS
WILL ONLY REACH THE TEENS MONDAY IN SPITE OF SOME SUN WITH HIGH
PRESSURE IN CONTROL. THE NEXT LOW PRESSURE SYSTEM AND PV ANOMALY
WILL BRING POTENTIAL FOR LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY
NIGHT.

THE COLD FRONT SHOULD BE THROUGH OUR AREA BY WEDNESDAY MORNING WITH
ANOTHER INTRUSION OF ARCTIC AIR AND BELOW NORMAL TEMPS FROM
WEDNESDAY NIGHT THROUGH LATE WEEK. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE LATE IN THE WEEK.

OVERALL THOUGH THE SETUP DOES NOT LOOK FAVORABLE FOR LAKE EFFECT
SNOW OF ANY SIGNIFICANCE LATE IN THE WEEK DUE TO THE VERY DRY ARCTIC
AIRMASS AND DRY FCST SOUNDINGS THURSDAY/FRIDAY AS WELL AS VERY LOW
INVERSION HEIGHTS BY THEN. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY
REACH THE TEENS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1130 AM EST FRI JAN 30 2015

MAINLY VFR CONDITIONS ARE EXPECTED THROUGH 18Z SATURDAY. A FEW
FLURRIES WILL LINGER AT KMKG INTERMITTENTLY THROUGH THE NEXT 24 HRS.
NW WINDS OF 10 TO 15 KTS WILL BACK TO THE SW AND SUBSIDE TO AOB 10
KTS TONIGHT INTO SATURDAY.


&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS IN
AROUND 20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE
FOR ICE DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...93






000
FXUS63 KGRR 302028
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
328 PM EST FRI JAN 30 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM

.SYNOPSIS...
ISSUED AT 328 PM EST FRI JAN 30 2015

LOW PRESSURE WILL BRING SOME SNOW ON SUNDAY WITH THE HIGHEST
AMOUNTS ACROSS FAR SOUTHERN LOWER MICHIGAN NEAR THE INDIANA
BORDER. VERY COLD WEATHER IS EXPECTED MONDAY WITH MORE SNOW
POSSIBLE TUESDAY NIGHT AND WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 328 PM EST FRI JAN 30 2015

THE STORM ON SUNDAY IS THE MAIN FORECAST PROBLEM IN THE NEAR TERM.
12Z MODEL GUIDANCE CONTINUES TO SHOW THE POTENTIAL FOR 4 OR MORE
INCHES OF SNOW ACROSS THE I-94 CORRIDOR BETWEEN SATURDAY NIGHT AND
SUNDAY NIGHT. HELD OFF ON HEADLINES FOR NOW BASED ON UNCERTAINTY
THAT THE RECENT MORE NORTHERLY JOG WILL LAST...ALTHOUGH THE CURRENT
TREND IS DEFINITELY IN THAT DIRECTION.

THE SYNOPTIC SET UP IS SIMILAR TO LAST SUNDAY WITH A COLD AND DRY
AIR MASS TO THE NORTH AND A LOW PASSING THROUGH THE OHIO VALLEY.
ONCE AGAIN WE EXPECT A SHARP SNOWFALL GRADIENT AS MESOSCALE BANDS
WILL ALIGN EAST TO WEST ACROSS THE SOUTHERN FORECAST AREA IN AREA OF
MID LEVEL F-GEN FORCING. WE BUMPED UP THE POPS AND QPF FOR SATURDAY
NIGHT THROUGH SUNDAY NIGHT WITH THE BULK OF THE SNOW FALLING SUNDAY
MORNING. SOME INCH AN HOUR RATES ARE POSSIBLE ACROSS THE FAR SOUTH
SUNDAY MORNING INTO THE AFTERNOON.

THE LOW IS CURRENTLY GATHERING STRENGTH ACROSS THE SOUTHWEST CONUS
AND IS BEING FED BY A DEEP PLUME OF TROPICAL MOISTURE FROM THE
EASTERN PACIFIC. THE LOW WILL ALSO GET GOOD GULF OF MEXICO INFLOW AS
IT MOVES EAST. MEANWHILE...EASTERLY FLOW DEVELOPS AHEAD OF THE
SYSTEM AND A MATURE CYCLONE WITH WARM AND COLD CONVEYOR BELTS TRACKS
ACROSS THE OHIO VALLEY WITH 12Z MODEL GUIDANCE SHOWING ENOUGH QPF TO
COME CLOSE TO WARNING CRITERIA ACROSS THE FAR SOUTH. SNOW TOTALS
WILL PROBABLY END UP 20 TO 1 OR GREATER GIVEN THE COLD AIR IN PLACE
DURING THIS EVENT.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 328 PM EST FRI JAN 30 2015

VERY COLD WEATHER WILL CONTINUE MONDAY WITH POTENTIAL FOR SINGLE
DIGIT BELOW TO ABOVE ZERO READINGS EARLY MONDAY MORNING. MAX TEMPS
WILL ONLY REACH THE TEENS MONDAY IN SPITE OF SOME SUN WITH HIGH
PRESSURE IN CONTROL. THE NEXT LOW PRESSURE SYSTEM AND PV ANOMALY
WILL BRING POTENTIAL FOR LAKE ENHANCED SNOW TUESDAY THROUGH TUESDAY
NIGHT.

THE COLD FRONT SHOULD BE THROUGH OUR AREA BY WEDNESDAY MORNING WITH
ANOTHER INTRUSION OF ARCTIC AIR AND BELOW NORMAL TEMPS FROM
WEDNESDAY NIGHT THROUGH LATE WEEK. A FEW LIGHT LAKE EFFECT SNOW
SHOWERS AND FLURRIES ARE POSSIBLE LATE IN THE WEEK.

OVERALL THOUGH THE SETUP DOES NOT LOOK FAVORABLE FOR LAKE EFFECT
SNOW OF ANY SIGNIFICANCE LATE IN THE WEEK DUE TO THE VERY DRY ARCTIC
AIRMASS AND DRY FCST SOUNDINGS THURSDAY/FRIDAY AS WELL AS VERY LOW
INVERSION HEIGHTS BY THEN. MAX TEMPS THURSDAY AND FRIDAY WILL ONLY
REACH THE TEENS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1130 AM EST FRI JAN 30 2015

MAINLY VFR CONDITIONS ARE EXPECTED THROUGH 18Z SATURDAY. A FEW
FLURRIES WILL LINGER AT KMKG INTERMITTENTLY THROUGH THE NEXT 24 HRS.
NW WINDS OF 10 TO 15 KTS WILL BACK TO THE SW AND SUBSIDE TO AOB 10
KTS TONIGHT INTO SATURDAY.


&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS IN
AROUND 20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE
FOR ICE DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...93





000
FXUS63 KGRR 301631
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1130 AM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 318 AM EST FRI JAN 30 2015

A COLD FRONT MOVED THROUGH LAST NIGHT BRINGING WITH IT GUSTY WINDS
AND SOME LIGHT SNOW. TODAY WILL BE COLDER WITH HIGHS AROUND 20 AND
LIGHT SNOW SHOWERS ALONG/WEST OF US-131.

A DEVELOPING STORM WILL MOVE ACROSS THE OHIO VALLEY SUNDAY BUT MAY
BE FAR ENOUGH NORTH TO GIVE SOUTHWEST LOWER MICHIGAN ACCUMULATING
SNOW. COLD AIR WITH HIGHS IN THE MID TEENS IS EXPECTED SUNDAY AND
MONDAY BEFORE WARMER TEMPERATURES MOVE IN BY TUESDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

FORECAST CONCERNS DEAL WITH A POTENTIAL STORM SUNDAY AND TO A LESSER
DEGREE LIGHT SNOW TODAY.

AS MENTIONED ABOVE A COLD FRONT MOVED THROUGH THE CWA A FEW HOURS
AGO. TEMPS ARE IN THE LOWER 20S AND WILL FALL A FEW MORE DEGREES
BEFORE MORNING. EXPECT COLDER TEMPS TODAY THAN YESTERDAY. HIGHS WILL
BE AROUND 20. RADAR SHOWS LIGHT LAKE EFFECT SNOW SHOWERS MOVING SSE
ACROSS THE CWA. INSTABILITY IS PRETTY GOOD WITH H8 TEMPS NEAR -17C
FLOWING OVER THE LAKE. THIS COLD AIR IS VERY TRANSITORY AND WILL
MOVE EAST TODAY PUTTING AN END TO THE SHSN BY LATE IN THE DAY.
BUFKIT RH PROFILES SHOW VERY SHALLOW MOISTURE WITH NOT MUCH LIFT SO
ANY ACCUMS WILL BE LESS THAN AN INCH.

HIGH PRESSURE WILL MOVE ACROSS THE CWA THIS EVENING AND SKIES MAY
BRIEFLY SCATTER BEFORE HIGHER CLOUDS ARRIVE IN THE WARM ADVECTION
PATTERN THAT WILL DEVELOP LATE TONIGHT. IT/S POSSIBLE TEMPS COULD
BRIEFLY DIP TO AROUND 10 TONIGHT BEFORE RISING AS CLOUDS MOVE IN BUT
THAT ISN`T CERTAIN AND I DIDN`T GO THAT LOW IN THE GRIDS EXCEPT IN
THE FAR NORTHEAST CORNER WHERE CLOUDS WILL BE THE LAST TO MOVE
OVER.

ANOTHER COLD FRONT WILL DROP SOUTH SATURDAY AND WE COULD SEE SOME
LIGHT SNOW FROM IT. BUT MOISTURE ISN/T IMPRESSIVE AND SO LITTLE IF
ANY ACCUMS EXPECTED.

THE GREATER CHANCE OF SNOW WILL COME SUNDAY WHEN A SOUTHERN STREAM
STORM MOVES OUT OF THE SOUTHERN PLAINS TOWARD THE OHIO VALLEY. MODEL
TRENDS HAVE BEEN A SLIGHT NUDGE TO THE NORTH. WE/VE INCREASED POPS
CONSIDERABLY SUNDAY OVER THE SOUTHERN HALF OF THE CWA. NAM BRINGS IN
SNOW LATE SATURDAY NIGHT AND CONTINUES THROUGH SUNDAY. WE MAY NEED
HEADLINES FOR THIS SYSTEM IF THE CURRENT TRACK HOLDS UP. SEVERAL
INCHES OF ACCUMULATION LOOKS POSSIBLE ESPECIALLY ALONG/SOUTH OF
I-94.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

CLEARING FOLLOWED BY COLD TEMPERATURES STILL EXPECTED MONDAY MORNING
OVER INTERIOR OF CENTRAL/NORTHERN LOWER MI WITH LOWS OF 10 BELOW OR
COLDER POSSIBLE IN SPOTS. FARTHER SOUTH TOWARDS I-94...SNOW WILL BE
EXITING THE AREA.

AFTER ANEMIC PROSPECTS FOR LAKE EFFECT SNOW MONDAY...POTENTIAL FOR
LAKE ENHANCED SNOW STEADILY INCREASES MONDAY NIGHT THROUGH TUESDAY
NIGHT WITH THE ARRIVAL OF A COMPACT UPPER POT VORT ANOMALY. TUESDAY
NIGHT ESPECIALLY COULD SEE A QUICK AND INTENSE CONVECTIVE BURST OF
SNOW WITH THE UPPER SYSTEM AND ENSUING ARCTIC COLD FRONT.

WEDNESDAY EVENING ALSO LOOKS INTERESTING WITH POTENTIAL IMPACTS TO
TRAVEL AS A REINFORCING COLD FRONT AND ATTENDANT DEEP MOISTURE ARE
ADVERTISED BY BOTH THE ECMWF/GFS TO PUSH THROUGH THE AREA. WE HAVE
SEEN RUN TO RUN CONSISTENCY WITH THE ECMWF AND NOW AGREEMENT WITH
THE GFS REGARDING THIS. CERTAINTY IS THEREFORE BUMPED UP A NOTCH BUT
STILL LOW OVERALL SINCE WE ARE DEALING WITH A DAY 5/6 FORECAST.
WE CAN SAY WITH BETTER CONFIDENCE THAT THE LATTER HALF OF THE WEEK
WILL BE SEASONABLY COLD IN THE WAKE OF THE FRONT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1130 AM EST FRI JAN 30 2015

MAINLY VFR CONDITIONS ARE EXPECTED THROUGH 18Z SATURDAY. A FEW
FLURRIES WILL LINGER AT KMKG INTERMITTENTLY THROUGH THE NEXT 24 HRS.
NW WINDS OF 10 TO 15 KTS WILL BACK TO THE SW AND SUBSIDE TO AOB 10
KTS TONIGHT INTO SATURDAY.

&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS IN
AROUND 20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE
FOR ICE DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...LAURENS
HYDROLOGY...93








000
FXUS63 KGRR 301631
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1130 AM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 318 AM EST FRI JAN 30 2015

A COLD FRONT MOVED THROUGH LAST NIGHT BRINGING WITH IT GUSTY WINDS
AND SOME LIGHT SNOW. TODAY WILL BE COLDER WITH HIGHS AROUND 20 AND
LIGHT SNOW SHOWERS ALONG/WEST OF US-131.

A DEVELOPING STORM WILL MOVE ACROSS THE OHIO VALLEY SUNDAY BUT MAY
BE FAR ENOUGH NORTH TO GIVE SOUTHWEST LOWER MICHIGAN ACCUMULATING
SNOW. COLD AIR WITH HIGHS IN THE MID TEENS IS EXPECTED SUNDAY AND
MONDAY BEFORE WARMER TEMPERATURES MOVE IN BY TUESDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

FORECAST CONCERNS DEAL WITH A POTENTIAL STORM SUNDAY AND TO A LESSER
DEGREE LIGHT SNOW TODAY.

AS MENTIONED ABOVE A COLD FRONT MOVED THROUGH THE CWA A FEW HOURS
AGO. TEMPS ARE IN THE LOWER 20S AND WILL FALL A FEW MORE DEGREES
BEFORE MORNING. EXPECT COLDER TEMPS TODAY THAN YESTERDAY. HIGHS WILL
BE AROUND 20. RADAR SHOWS LIGHT LAKE EFFECT SNOW SHOWERS MOVING SSE
ACROSS THE CWA. INSTABILITY IS PRETTY GOOD WITH H8 TEMPS NEAR -17C
FLOWING OVER THE LAKE. THIS COLD AIR IS VERY TRANSITORY AND WILL
MOVE EAST TODAY PUTTING AN END TO THE SHSN BY LATE IN THE DAY.
BUFKIT RH PROFILES SHOW VERY SHALLOW MOISTURE WITH NOT MUCH LIFT SO
ANY ACCUMS WILL BE LESS THAN AN INCH.

HIGH PRESSURE WILL MOVE ACROSS THE CWA THIS EVENING AND SKIES MAY
BRIEFLY SCATTER BEFORE HIGHER CLOUDS ARRIVE IN THE WARM ADVECTION
PATTERN THAT WILL DEVELOP LATE TONIGHT. IT/S POSSIBLE TEMPS COULD
BRIEFLY DIP TO AROUND 10 TONIGHT BEFORE RISING AS CLOUDS MOVE IN BUT
THAT ISN`T CERTAIN AND I DIDN`T GO THAT LOW IN THE GRIDS EXCEPT IN
THE FAR NORTHEAST CORNER WHERE CLOUDS WILL BE THE LAST TO MOVE
OVER.

ANOTHER COLD FRONT WILL DROP SOUTH SATURDAY AND WE COULD SEE SOME
LIGHT SNOW FROM IT. BUT MOISTURE ISN/T IMPRESSIVE AND SO LITTLE IF
ANY ACCUMS EXPECTED.

THE GREATER CHANCE OF SNOW WILL COME SUNDAY WHEN A SOUTHERN STREAM
STORM MOVES OUT OF THE SOUTHERN PLAINS TOWARD THE OHIO VALLEY. MODEL
TRENDS HAVE BEEN A SLIGHT NUDGE TO THE NORTH. WE/VE INCREASED POPS
CONSIDERABLY SUNDAY OVER THE SOUTHERN HALF OF THE CWA. NAM BRINGS IN
SNOW LATE SATURDAY NIGHT AND CONTINUES THROUGH SUNDAY. WE MAY NEED
HEADLINES FOR THIS SYSTEM IF THE CURRENT TRACK HOLDS UP. SEVERAL
INCHES OF ACCUMULATION LOOKS POSSIBLE ESPECIALLY ALONG/SOUTH OF
I-94.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

CLEARING FOLLOWED BY COLD TEMPERATURES STILL EXPECTED MONDAY MORNING
OVER INTERIOR OF CENTRAL/NORTHERN LOWER MI WITH LOWS OF 10 BELOW OR
COLDER POSSIBLE IN SPOTS. FARTHER SOUTH TOWARDS I-94...SNOW WILL BE
EXITING THE AREA.

AFTER ANEMIC PROSPECTS FOR LAKE EFFECT SNOW MONDAY...POTENTIAL FOR
LAKE ENHANCED SNOW STEADILY INCREASES MONDAY NIGHT THROUGH TUESDAY
NIGHT WITH THE ARRIVAL OF A COMPACT UPPER POT VORT ANOMALY. TUESDAY
NIGHT ESPECIALLY COULD SEE A QUICK AND INTENSE CONVECTIVE BURST OF
SNOW WITH THE UPPER SYSTEM AND ENSUING ARCTIC COLD FRONT.

WEDNESDAY EVENING ALSO LOOKS INTERESTING WITH POTENTIAL IMPACTS TO
TRAVEL AS A REINFORCING COLD FRONT AND ATTENDANT DEEP MOISTURE ARE
ADVERTISED BY BOTH THE ECMWF/GFS TO PUSH THROUGH THE AREA. WE HAVE
SEEN RUN TO RUN CONSISTENCY WITH THE ECMWF AND NOW AGREEMENT WITH
THE GFS REGARDING THIS. CERTAINTY IS THEREFORE BUMPED UP A NOTCH BUT
STILL LOW OVERALL SINCE WE ARE DEALING WITH A DAY 5/6 FORECAST.
WE CAN SAY WITH BETTER CONFIDENCE THAT THE LATTER HALF OF THE WEEK
WILL BE SEASONABLY COLD IN THE WAKE OF THE FRONT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY)
ISSUED AT 1130 AM EST FRI JAN 30 2015

MAINLY VFR CONDITIONS ARE EXPECTED THROUGH 18Z SATURDAY. A FEW
FLURRIES WILL LINGER AT KMKG INTERMITTENTLY THROUGH THE NEXT 24 HRS.
NW WINDS OF 10 TO 15 KTS WILL BACK TO THE SW AND SUBSIDE TO AOB 10
KTS TONIGHT INTO SATURDAY.

&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS IN
AROUND 20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE
FOR ICE DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...LAURENS
HYDROLOGY...93









000
FXUS63 KGRR 301136
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
636 AM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 318 AM EST FRI JAN 30 2015

A COLD FRONT MOVED THROUGH LAST NIGHT BRINGING WITH IT GUSTY WINDS
AND SOME LIGHT SNOW. TODAY WILL BE COLDER WITH HIGHS AROUND 20 AND
LIGHT SNOW SHOWERS ALONG/WEST OF US-131.

A DEVELOPING STORM WILL MOVE ACROSS THE OHIO VALLEY SUNDAY BUT MAY
BE FAR ENOUGH NORTH TO GIVE SOUTHWEST LOWER MICHIGAN ACCUMULATING
SNOW. COLD AIR WITH HIGHS IN THE MID TEENS IS EXPECTED SUNDAY AND
MONDAY BEFORE WARMER TEMPERATURES MOVE IN BY TUESDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

FORECAST CONCERNS DEAL WITH A POTENTIAL STORM SUNDAY AND TO A LESSER
DEGREE LIGHT SNOW TODAY.

AS MENTIONED ABOVE A COLD FRONT MOVED THROUGH THE CWA A FEW HOURS
AGO. TEMPS ARE IN THE LOWER 20S AND WILL FALL A FEW MORE DEGREES
BEFORE MORNING. EXPECT COLDER TEMPS TODAY THAN YESTERDAY. HIGHS WILL
BE AROUND 20. RADAR SHOWS LIGHT LAKE EFFECT SNOW SHOWERS MOVING SSE
ACROSS THE CWA. INSTABILITY IS PRETTY GOOD WITH H8 TEMPS NEAR -17C
FLOWING OVER THE LAKE. THIS COLD AIR IS VERY TRANSITORY AND WILL
MOVE EAST TODAY PUTTING AN END TO THE SHSN BY LATE IN THE DAY.
BUFKIT RH PROFILES SHOW VERY SHALLOW MOISTURE WITH NOT MUCH LIFT SO
ANY ACCUMS WILL BE LESS THAN AN INCH.

HIGH PRESSURE WILL MOVE ACROSS THE CWA THIS EVENING AND SKIES MAY
BRIEFLY SCATTER BEFORE HIGHER CLOUDS ARRIVE IN THE WARM ADVECTION
PATTERN THAT WILL DEVELOP LATE TONIGHT. IT/S POSSIBLE TEMPS COULD
BRIEFLY DIP TO AROUND 10 TONIGHT BEFORE RISING AS CLOUDS MOVE IN BUT
THAT ISN`T CERTAIN AND I DIDN`T GO THAT LOW IN THE GRIDS EXCEPT IN
THE FAR NORTHEAST CORNER WHERE CLOUDS WILL BE THE LAST TO MOVE
OVER.

ANOTHER COLD FRONT WILL DROP SOUTH SATURDAY AND WE COULD SEE SOME
LIGHT SNOW FROM IT. BUT MOISTURE ISN/T IMPRESSIVE AND SO LITTLE IF
ANY ACCUMS EXPECTED.

THE GREATER CHANCE OF SNOW WILL COME SUNDAY WHEN A SOUTHERN STREAM
STORM MOVES OUT OF THE SOUTHERN PLAINS TOWARD THE OHIO VALLEY. MODEL
TRENDS HAVE BEEN A SLIGHT NUDGE TO THE NORTH. WE/VE INCREASED POPS
CONSIDERABLY SUNDAY OVER THE SOUTHERN HALF OF THE CWA. NAM BRINGS IN
SNOW LATE SATURDAY NIGHT AND CONTINUES THROUGH SUNDAY. WE MAY NEED
HEADLINES FOR THIS SYSTEM IF THE CURRENT TRACK HOLDS UP. SEVERAL
INCHES OF ACCUMULATION LOOKS POSSIBLE ESPECIALLY ALONG/SOUTH OF
I-94.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

CLEARING FOLLOWED BY COLD TEMPERATURES STILL EXPECTED MONDAY MORNING
OVER INTERIOR OF CENTRAL/NORTHERN LOWER MI WITH LOWS OF 10 BELOW OR
COLDER POSSIBLE IN SPOTS. FARTHER SOUTH TOWARDS I-94...SNOW WILL BE
EXITING THE AREA.

AFTER ANEMIC PROSPECTS FOR LAKE EFFECT SNOW MONDAY...POTENTIAL FOR
LAKE ENHANCED SNOW STEADILY INCREASES MONDAY NIGHT THROUGH TUESDAY
NIGHT WITH THE ARRIVAL OF A COMPACT UPPER POT VORT ANOMALY. TUESDAY
NIGHT ESPECIALLY COULD SEE A QUICK AND INTENSE CONVECTIVE BURST OF
SNOW WITH THE UPPER SYSTEM AND ENSUING ARCTIC COLD FRONT.

WEDNESDAY EVENING ALSO LOOKS INTERESTING WITH POTENTIAL IMPACTS TO
TRAVEL AS A REINFORCING COLD FRONT AND ATTENDANT DEEP MOISTURE ARE
ADVERTISED BY BOTH THE ECMWF/GFS TO PUSH THROUGH THE AREA. WE HAVE
SEEN RUN TO RUN CONSISTENCY WITH THE ECMWF AND NOW AGREEMENT WITH
THE GFS REGARDING THIS. CERTAINTY IS THEREFORE BUMPED UP A NOTCH BUT
STILL LOW OVERALL SINCE WE ARE DEALING WITH A DAY 5/6 FORECAST.
WE CAN SAY WITH BETTER CONFIDENCE THAT THE LATTER HALF OF THE WEEK
WILL BE SEASONABLY COLD IN THE WAKE OF THE FRONT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 635 AM EST FRI JAN 30 2015

NO CHANGES TO EARLIER THINKING. HIGH CONFIDENCE THAT IFR WILL NOT
BE AN ISSUE. OVERALL WE EXPECT VFR WITH SOME MVR CIGS ABOVE
2000 FT POSSIBLE EARLY ON AT THE LAN AND JXN TERMINALS. AS NOTED
PREVIOUSLY...MAY SEE BRIEF CLEARING EARLY AT SOME TERMINALS BUT
CLOUDS SHOULD FILL IN AGAIN BY LATE MORNING.

&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS IN
AROUND 20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE
FOR ICE DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...93







000
FXUS63 KGRR 301136
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
636 AM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 318 AM EST FRI JAN 30 2015

A COLD FRONT MOVED THROUGH LAST NIGHT BRINGING WITH IT GUSTY WINDS
AND SOME LIGHT SNOW. TODAY WILL BE COLDER WITH HIGHS AROUND 20 AND
LIGHT SNOW SHOWERS ALONG/WEST OF US-131.

A DEVELOPING STORM WILL MOVE ACROSS THE OHIO VALLEY SUNDAY BUT MAY
BE FAR ENOUGH NORTH TO GIVE SOUTHWEST LOWER MICHIGAN ACCUMULATING
SNOW. COLD AIR WITH HIGHS IN THE MID TEENS IS EXPECTED SUNDAY AND
MONDAY BEFORE WARMER TEMPERATURES MOVE IN BY TUESDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

FORECAST CONCERNS DEAL WITH A POTENTIAL STORM SUNDAY AND TO A LESSER
DEGREE LIGHT SNOW TODAY.

AS MENTIONED ABOVE A COLD FRONT MOVED THROUGH THE CWA A FEW HOURS
AGO. TEMPS ARE IN THE LOWER 20S AND WILL FALL A FEW MORE DEGREES
BEFORE MORNING. EXPECT COLDER TEMPS TODAY THAN YESTERDAY. HIGHS WILL
BE AROUND 20. RADAR SHOWS LIGHT LAKE EFFECT SNOW SHOWERS MOVING SSE
ACROSS THE CWA. INSTABILITY IS PRETTY GOOD WITH H8 TEMPS NEAR -17C
FLOWING OVER THE LAKE. THIS COLD AIR IS VERY TRANSITORY AND WILL
MOVE EAST TODAY PUTTING AN END TO THE SHSN BY LATE IN THE DAY.
BUFKIT RH PROFILES SHOW VERY SHALLOW MOISTURE WITH NOT MUCH LIFT SO
ANY ACCUMS WILL BE LESS THAN AN INCH.

HIGH PRESSURE WILL MOVE ACROSS THE CWA THIS EVENING AND SKIES MAY
BRIEFLY SCATTER BEFORE HIGHER CLOUDS ARRIVE IN THE WARM ADVECTION
PATTERN THAT WILL DEVELOP LATE TONIGHT. IT/S POSSIBLE TEMPS COULD
BRIEFLY DIP TO AROUND 10 TONIGHT BEFORE RISING AS CLOUDS MOVE IN BUT
THAT ISN`T CERTAIN AND I DIDN`T GO THAT LOW IN THE GRIDS EXCEPT IN
THE FAR NORTHEAST CORNER WHERE CLOUDS WILL BE THE LAST TO MOVE
OVER.

ANOTHER COLD FRONT WILL DROP SOUTH SATURDAY AND WE COULD SEE SOME
LIGHT SNOW FROM IT. BUT MOISTURE ISN/T IMPRESSIVE AND SO LITTLE IF
ANY ACCUMS EXPECTED.

THE GREATER CHANCE OF SNOW WILL COME SUNDAY WHEN A SOUTHERN STREAM
STORM MOVES OUT OF THE SOUTHERN PLAINS TOWARD THE OHIO VALLEY. MODEL
TRENDS HAVE BEEN A SLIGHT NUDGE TO THE NORTH. WE/VE INCREASED POPS
CONSIDERABLY SUNDAY OVER THE SOUTHERN HALF OF THE CWA. NAM BRINGS IN
SNOW LATE SATURDAY NIGHT AND CONTINUES THROUGH SUNDAY. WE MAY NEED
HEADLINES FOR THIS SYSTEM IF THE CURRENT TRACK HOLDS UP. SEVERAL
INCHES OF ACCUMULATION LOOKS POSSIBLE ESPECIALLY ALONG/SOUTH OF
I-94.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

CLEARING FOLLOWED BY COLD TEMPERATURES STILL EXPECTED MONDAY MORNING
OVER INTERIOR OF CENTRAL/NORTHERN LOWER MI WITH LOWS OF 10 BELOW OR
COLDER POSSIBLE IN SPOTS. FARTHER SOUTH TOWARDS I-94...SNOW WILL BE
EXITING THE AREA.

AFTER ANEMIC PROSPECTS FOR LAKE EFFECT SNOW MONDAY...POTENTIAL FOR
LAKE ENHANCED SNOW STEADILY INCREASES MONDAY NIGHT THROUGH TUESDAY
NIGHT WITH THE ARRIVAL OF A COMPACT UPPER POT VORT ANOMALY. TUESDAY
NIGHT ESPECIALLY COULD SEE A QUICK AND INTENSE CONVECTIVE BURST OF
SNOW WITH THE UPPER SYSTEM AND ENSUING ARCTIC COLD FRONT.

WEDNESDAY EVENING ALSO LOOKS INTERESTING WITH POTENTIAL IMPACTS TO
TRAVEL AS A REINFORCING COLD FRONT AND ATTENDANT DEEP MOISTURE ARE
ADVERTISED BY BOTH THE ECMWF/GFS TO PUSH THROUGH THE AREA. WE HAVE
SEEN RUN TO RUN CONSISTENCY WITH THE ECMWF AND NOW AGREEMENT WITH
THE GFS REGARDING THIS. CERTAINTY IS THEREFORE BUMPED UP A NOTCH BUT
STILL LOW OVERALL SINCE WE ARE DEALING WITH A DAY 5/6 FORECAST.
WE CAN SAY WITH BETTER CONFIDENCE THAT THE LATTER HALF OF THE WEEK
WILL BE SEASONABLY COLD IN THE WAKE OF THE FRONT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 635 AM EST FRI JAN 30 2015

NO CHANGES TO EARLIER THINKING. HIGH CONFIDENCE THAT IFR WILL NOT
BE AN ISSUE. OVERALL WE EXPECT VFR WITH SOME MVR CIGS ABOVE
2000 FT POSSIBLE EARLY ON AT THE LAN AND JXN TERMINALS. AS NOTED
PREVIOUSLY...MAY SEE BRIEF CLEARING EARLY AT SOME TERMINALS BUT
CLOUDS SHOULD FILL IN AGAIN BY LATE MORNING.

&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS IN
AROUND 20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE
FOR ICE DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...93








000
FXUS63 KGRR 300818
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
318 AM EST FRI JAN 30 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO

.SYNOPSIS...
ISSUED AT 318 AM EST FRI JAN 30 2015

A COLD FRONT MOVED THROUGH LAST NIGHT BRINGING WITH IT GUSTY WINDS
AND SOME LIGHT SNOW. TODAY WILL BE COLDER WITH HIGHS AROUND 20 AND
LIGHT SNOW SHOWERS ALONG/WEST OF US-131.

A DEVELOPING STORM WILL MOVE ACROSS THE OHIO VALLEY SUNDAY BUT MAY
BE FAR ENOUGH NORTH TO GIVE SOUTHWEST LOWER MICHIGAN ACCUMULATING
SNOW. COLD AIR WITH HIGHS IN THE MID TEENS IS EXPECTED SUNDAY AND
MONDAY BEFORE WARMER TEMPERATURES MOVE IN BY TUESDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

FORECAST CONCERNS DEAL WITH A POTENTIAL STORM SUNDAY AND TO A LESSER
DEGREE LIGHT SNOW TODAY.

AS MENTIONED ABOVE A COLD FRONT MOVED THROUGH THE CWA A FEW HOURS
AGO. TEMPS ARE IN THE LOWER 20S AND WILL FALL A FEW MORE DEGREES
BEFORE MORNING. EXPECT COLDER TEMPS TODAY THAN YESTERDAY. HIGHS WILL
BE AROUND 20. RADAR SHOWS LIGHT LAKE EFFECT SNOW SHOWERS MOVING SSE
ACROSS THE CWA. INSTABILITY IS PRETTY GOOD WITH H8 TEMPS NEAR -17C
FLOWING OVER THE LAKE. THIS COLD AIR IS VERY TRANSITORY AND WILL
MOVE EAST TODAY PUTTING AN END TO THE SHSN BY LATE IN THE DAY.
BUFKIT RH PROFILES SHOW VERY SHALLOW MOISTURE WITH NOT MUCH LIFT SO
ANY ACCUMS WILL BE LESS THAN AN INCH.

HIGH PRESSURE WILL MOVE ACROSS THE CWA THIS EVENING AND SKIES MAY
BRIEFLY SCATTER BEFORE HIGHER CLOUDS ARRIVE IN THE WARM ADVECTION
PATTERN THAT WILL DEVELOP LATE TONIGHT. IT/S POSSIBLE TEMPS COULD
BRIEFLY DIP TO AROUND 10 TONIGHT BEFORE RISING AS CLOUDS MOVE IN BUT
THAT ISN`T CERTAIN AND I DIDN`T GO THAT LOW IN THE GRIDS EXCEPT IN
THE FAR NORTHEAST CORNER WHERE CLOUDS WILL BE THE LAST TO MOVE
OVER.

ANOTHER COLD FRONT WILL DROP SOUTH SATURDAY AND WE COULD SEE SOME
LIGHT SNOW FROM IT. BUT MOISTURE ISN/T IMPRESSIVE AND SO LITTLE IF
ANY ACCUMS EXPECTED.

THE GREATER CHANCE OF SNOW WILL COME SUNDAY WHEN A SOUTHERN STREAM
STORM MOVES OUT OF THE SOUTHERN PLAINS TOWARD THE OHIO VALLEY. MODEL
TRENDS HAVE BEEN A SLIGHT NUDGE TO THE NORTH. WE/VE INCREASED POPS
CONSIDERABLY SUNDAY OVER THE SOUTHERN HALF OF THE CWA. NAM BRINGS IN
SNOW LATE SATURDAY NIGHT AND CONTINUES THROUGH SUNDAY. WE MAY NEED
HEADLINES FOR THIS SYSTEM IF THE CURRENT TRACK HOLDS UP. SEVERAL
INCHES OF ACCUMULATION LOOKS POSSIBLE ESPECIALLY ALONG/SOUTH OF
I-94.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

CLEARING FOLLOWED BY COLD TEMPERATURES STILL EXPECTED MONDAY MORNING
OVER INTERIOR OF CENTRAL/NORTHERN LOWER MI WITH LOWS OF 10 BELOW OR
COLDER POSSIBLE IN SPOTS. FARTHER SOUTH TOWARDS I-94...SNOW WILL BE
EXITING THE AREA.

AFTER ANEMIC PROSPECTS FOR LAKE EFFECT SNOW MONDAY...POTENTIAL FOR
LAKE ENHANCED SNOW STEADILY INCREASES MONDAY NIGHT THROUGH TUESDAY
NIGHT WITH THE ARRIVAL OF A COMPACT UPPER POT VORT ANOMALY. TUESDAY
NIGHT ESPECIALLY COULD SEE A QUICK AND INTENSE CONVECTIVE BURST OF
SNOW WITH THE UPPER SYSTEM AND ENSUING ARCTIC COLD FRONT.

WEDNESDAY EVENING ALSO LOOKS INTERESTING WITH POTENTIAL IMPACTS TO
TRAVEL AS A REINFORCING COLD FRONT AND ATTENDANT DEEP MOISTURE ARE
ADVERTISED BY BOTH THE ECMWF/GFS TO PUSH THROUGH THE AREA. WE HAVE
SEEN RUN TO RUN CONSISTENCY WITH THE ECMWF AND NOW AGREEMENT WITH
THE GFS REGARDING THIS. CERTAINTY IS THEREFORE BUMPED UP A NOTCH BUT
STILL LOW OVERALL SINCE WE ARE DEALING WITH A DAY 5/6 FORECAST.
WE CAN SAY WITH BETTER CONFIDENCE THAT THE LATTER HALF OF THE WEEK
WILL BE SEASONABLY COLD IN THE WAKE OF THE FRONT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1159 PM EST THU JAN 29 2015

THE TREND OVERNIGHT WILL BE FOR VFR CONDITIONS TO BECOME MORE
WIDESPREAD DUE TO THE ARRIVAL OF A DRIER (AND MUCH COLDER) AIR
MASS FROM THE NORTH. HOWEVER MKG MAY SEE OCNL IFR VSBYS CONTINUE AS
LAKE EFFECT SNOW SHOWERS CLIP THE COAST.

SNOW SHOWERS INLAND FROM LAKE MICHIGAN AT MIDNIGHT ARE EXPECTED
TO END BY 4 AM OR SO AND SEVERAL TERMINALS MAY ACTUALLY SEE SKIES
BECOME SCATTERED BEFORE DAYBREAK. ANY CLEARING THAT TAKES PLACE
LATE TONIGHT AND FRIDAY MORNING WILL PROBABLY FILL BACK IN ON
FRIDAY AFTERNOON. HOWEVER CLOUD BASES SHOULD BE MOSTLY VFR.

GUSTY NORTH-NORTHWEST WINDS FOR A FEW MORE HOURS WILL RESULT IN
CONTINUED LOW LEVEL TURBULENCE... BUT THE WINDS WILL DIMINISH TO
AROUND 10 KTS VERY LATE TONIGHT INTO FRIDAY.


&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS IN
AROUND 20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE
FOR ICE DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...MEADE
HYDROLOGY...93












000
FXUS63 KGRR 300818
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
318 AM EST FRI JAN 30 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/HYDRO

.SYNOPSIS...
ISSUED AT 318 AM EST FRI JAN 30 2015

A COLD FRONT MOVED THROUGH LAST NIGHT BRINGING WITH IT GUSTY WINDS
AND SOME LIGHT SNOW. TODAY WILL BE COLDER WITH HIGHS AROUND 20 AND
LIGHT SNOW SHOWERS ALONG/WEST OF US-131.

A DEVELOPING STORM WILL MOVE ACROSS THE OHIO VALLEY SUNDAY BUT MAY
BE FAR ENOUGH NORTH TO GIVE SOUTHWEST LOWER MICHIGAN ACCUMULATING
SNOW. COLD AIR WITH HIGHS IN THE MID TEENS IS EXPECTED SUNDAY AND
MONDAY BEFORE WARMER TEMPERATURES MOVE IN BY TUESDAY.

&&

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

FORECAST CONCERNS DEAL WITH A POTENTIAL STORM SUNDAY AND TO A LESSER
DEGREE LIGHT SNOW TODAY.

AS MENTIONED ABOVE A COLD FRONT MOVED THROUGH THE CWA A FEW HOURS
AGO. TEMPS ARE IN THE LOWER 20S AND WILL FALL A FEW MORE DEGREES
BEFORE MORNING. EXPECT COLDER TEMPS TODAY THAN YESTERDAY. HIGHS WILL
BE AROUND 20. RADAR SHOWS LIGHT LAKE EFFECT SNOW SHOWERS MOVING SSE
ACROSS THE CWA. INSTABILITY IS PRETTY GOOD WITH H8 TEMPS NEAR -17C
FLOWING OVER THE LAKE. THIS COLD AIR IS VERY TRANSITORY AND WILL
MOVE EAST TODAY PUTTING AN END TO THE SHSN BY LATE IN THE DAY.
BUFKIT RH PROFILES SHOW VERY SHALLOW MOISTURE WITH NOT MUCH LIFT SO
ANY ACCUMS WILL BE LESS THAN AN INCH.

HIGH PRESSURE WILL MOVE ACROSS THE CWA THIS EVENING AND SKIES MAY
BRIEFLY SCATTER BEFORE HIGHER CLOUDS ARRIVE IN THE WARM ADVECTION
PATTERN THAT WILL DEVELOP LATE TONIGHT. IT/S POSSIBLE TEMPS COULD
BRIEFLY DIP TO AROUND 10 TONIGHT BEFORE RISING AS CLOUDS MOVE IN BUT
THAT ISN`T CERTAIN AND I DIDN`T GO THAT LOW IN THE GRIDS EXCEPT IN
THE FAR NORTHEAST CORNER WHERE CLOUDS WILL BE THE LAST TO MOVE
OVER.

ANOTHER COLD FRONT WILL DROP SOUTH SATURDAY AND WE COULD SEE SOME
LIGHT SNOW FROM IT. BUT MOISTURE ISN/T IMPRESSIVE AND SO LITTLE IF
ANY ACCUMS EXPECTED.

THE GREATER CHANCE OF SNOW WILL COME SUNDAY WHEN A SOUTHERN STREAM
STORM MOVES OUT OF THE SOUTHERN PLAINS TOWARD THE OHIO VALLEY. MODEL
TRENDS HAVE BEEN A SLIGHT NUDGE TO THE NORTH. WE/VE INCREASED POPS
CONSIDERABLY SUNDAY OVER THE SOUTHERN HALF OF THE CWA. NAM BRINGS IN
SNOW LATE SATURDAY NIGHT AND CONTINUES THROUGH SUNDAY. WE MAY NEED
HEADLINES FOR THIS SYSTEM IF THE CURRENT TRACK HOLDS UP. SEVERAL
INCHES OF ACCUMULATION LOOKS POSSIBLE ESPECIALLY ALONG/SOUTH OF
I-94.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST FRI JAN 30 2015

CLEARING FOLLOWED BY COLD TEMPERATURES STILL EXPECTED MONDAY MORNING
OVER INTERIOR OF CENTRAL/NORTHERN LOWER MI WITH LOWS OF 10 BELOW OR
COLDER POSSIBLE IN SPOTS. FARTHER SOUTH TOWARDS I-94...SNOW WILL BE
EXITING THE AREA.

AFTER ANEMIC PROSPECTS FOR LAKE EFFECT SNOW MONDAY...POTENTIAL FOR
LAKE ENHANCED SNOW STEADILY INCREASES MONDAY NIGHT THROUGH TUESDAY
NIGHT WITH THE ARRIVAL OF A COMPACT UPPER POT VORT ANOMALY. TUESDAY
NIGHT ESPECIALLY COULD SEE A QUICK AND INTENSE CONVECTIVE BURST OF
SNOW WITH THE UPPER SYSTEM AND ENSUING ARCTIC COLD FRONT.

WEDNESDAY EVENING ALSO LOOKS INTERESTING WITH POTENTIAL IMPACTS TO
TRAVEL AS A REINFORCING COLD FRONT AND ATTENDANT DEEP MOISTURE ARE
ADVERTISED BY BOTH THE ECMWF/GFS TO PUSH THROUGH THE AREA. WE HAVE
SEEN RUN TO RUN CONSISTENCY WITH THE ECMWF AND NOW AGREEMENT WITH
THE GFS REGARDING THIS. CERTAINTY IS THEREFORE BUMPED UP A NOTCH BUT
STILL LOW OVERALL SINCE WE ARE DEALING WITH A DAY 5/6 FORECAST.
WE CAN SAY WITH BETTER CONFIDENCE THAT THE LATTER HALF OF THE WEEK
WILL BE SEASONABLY COLD IN THE WAKE OF THE FRONT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1159 PM EST THU JAN 29 2015

THE TREND OVERNIGHT WILL BE FOR VFR CONDITIONS TO BECOME MORE
WIDESPREAD DUE TO THE ARRIVAL OF A DRIER (AND MUCH COLDER) AIR
MASS FROM THE NORTH. HOWEVER MKG MAY SEE OCNL IFR VSBYS CONTINUE AS
LAKE EFFECT SNOW SHOWERS CLIP THE COAST.

SNOW SHOWERS INLAND FROM LAKE MICHIGAN AT MIDNIGHT ARE EXPECTED
TO END BY 4 AM OR SO AND SEVERAL TERMINALS MAY ACTUALLY SEE SKIES
BECOME SCATTERED BEFORE DAYBREAK. ANY CLEARING THAT TAKES PLACE
LATE TONIGHT AND FRIDAY MORNING WILL PROBABLY FILL BACK IN ON
FRIDAY AFTERNOON. HOWEVER CLOUD BASES SHOULD BE MOSTLY VFR.

GUSTY NORTH-NORTHWEST WINDS FOR A FEW MORE HOURS WILL RESULT IN
CONTINUED LOW LEVEL TURBULENCE... BUT THE WINDS WILL DIMINISH TO
AROUND 10 KTS VERY LATE TONIGHT INTO FRIDAY.


&&

.HYDROLOGY...
ISSUED AT 318 AM EST FRI JAN 30 2015

ICE FORMATION IS THE MAIN CONCERN DURING THE NEXT FEW DAYS. HIGHS IN
AROUND 20 TODAY AND AROUND 15 SUNDAY AND MONDAY WILL BE FAVORABLE
FOR ICE DEVELOPMENT.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...93
SHORT TERM...93
LONG TERM...TJT
AVIATION...MEADE
HYDROLOGY...93













000
FXUS63 KGRR 300501
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1201 AM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 312 PM EST THU JAN 29 2015

LOW PRESSURE WILL TRACK EASTWARD AWAY FROM THE REGION TONIGHT TAKING
MOST OF THE PRECIPITATION WITH IT.  COLD HIGH PRESSURE WILL BUILD IN
FOR FRIDAY LEADING TO MAINLY DRY CONDITIONS. A COLD FRONT WILL
WEAKEN AS IT TRACKS THROUGH LOWER MICHIGAN SATURDAY. LOW PRESSURE
WILL THEN TRACK UP THE OHIO VALLEY FOR SUNDAY. THIS SYSTEM COULD
BRING SOME SNOW TO SOUTHERN PARTS OF LOWER MICHIGAN.

&&

.UPDATE...
ISSUED AT 915 PM EST THU JAN 29 2015

FAIRLY STRONG SHORT WAVE SEEN ON WV IMAGERY OVER NRN WISCONSIN HAS
CAUSED A FLARE UP OF SHSN ACTIVITY ACROSS THE WESTERN CWA THIS
EVENING. VSBYS HAVE FALLEN TO NEAR A MILE AT SOME LOCATIONS AS
SNOW BANDS MOVE SOUTH FROM LAKE SUPERIOR. SHSN SHOULD DIMINISH
SOME AFTER 06Z AS THE WAVE MOVES EAST. UPDATED GRIDS OVER THE
WESTERN CWA TO REFLECT HIGHER POPS THIS EVENING.

UPDATE ISSUED AT 710 PM EST THU JAN 29 2015

STILL GETTING SOME REPORTS OF LIGHT DRIZZLE/FREEZING DRIZZLE
ACCOMPANYING THE LIGHT SNOW SHOWERS THIS EVENING. WILL UPDATE THE
FCST TO INCLUDE THE DRIZZLE FOR A FEW MORE HOURS THIS EVENING...
MAINLY FROM GRR TO THE SOUTH AND EAST. NO IMPACTS EXPECTED GIVEN
VERY LIGHT/PATCHY NATURE OF THE DRIZZLE AND THAT ROADS WERE
ALREADY SIGNIFICANTLY TREATED FROM EARLIER EVENT.

THE DEPARTURE OF THE DEEPER MOISTURE HAS RESULTED IN PROBLEMS
KEEPING A SATURATED DGZ IN THE CLOUD LAYER...THUS THE PATCHY
DRIZZLE. HOWEVER THE ARRIVAL OF THE LOW LEVEL COLD AIR REINTRODUCES
A SATURATED DGZ AT MOST LOCATIONS BY MIDNIGHT PER BUFKIT
OVERVIEWS... IF NOT EARLIER.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 312 PM EST THU JAN 29 2015

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH WHETHER TO EXTEND
THE HEADLINES THIS EVENING.

TEMPERATURES HAVE BEEN CLIMBING AND MOST LOCATIONS ARE NEAR OR ABOVE
FREEZING.  THE PRECIPITATION HAS BEEN WEAKENING.  COLDER CLOUD TOPS
WERE PUSHING EAST OF LANSING SUPPORTING NOT MUCH ADDITIONAL
PRECIPITATION FROM THIS SYSTEM  WHAT DOES FALL SHOULD BE MOSTLY
SNOW...EXCEPT SOME RAIN COULD MIX IN AROUND INTERSTATE 94.  THERE
ENOUGH WARMTH IN THE LOW LEVELS EXISTS TO ALLOW FOR MELTING. ALSO
SPEEDS ON THE HIGHWAY ARE CLOSE TO NORMAL...SUGGESTING THE IMPACT
HAS DIMINISHED FROM THE EARLIER SNOW AND FREEZING RAIN. AS A RESULT
OF ALL THIS THE WINTER WEATHER ADVISORY WILL BE CANCELED SLIGHTLY
EARLY.

NORTHERLY COLD AIR ADVECTION SETS UP OVERNIGHT AND THAT COULD WILL
SUPPORT SOME LAKE EFFECT AS THE COLDER AIR MOVES IN. THIS SETUP
LOOKS WEAK. THE DGZ IS SHOWN TO BE MOIST...BUT SUBSIDENCE IS
NOTED. THIS WILL ACT TO KEEP THE POTENTIAL FOR ACCUMULATIONS LOW. I
WILL FEATURE HIGHEST POPS ALONG THE LAKESHORE.

THE SURFACE HIGH DRIFTS OVER THE AREA FRIDAY NIGHT. GIVEN THE COLD
AIRMASS IN PLACE...WITH LIGHT WINDS AND AT LEAST LIMITED CLOUDS TO
START THE NIGHT...TEMPERATURES WILL END UP AS A WELL BELOW
NORMAL.

WARM AIR ADVECTION DEVELOPS SATURDAY. THIS COULD LEAD TO LAKE
EFFECT/ENHANCED SNOW AS THE FLOW TURNS SOUTHWEST. THE TIMING OF
THE ARRIVAL OF THE MID LEVEL MOISTURE DOES NOT COINCIDE WITH THE
INCREASING LOW LEVEL MOISTURE. THUS ONLY A LIMITED CHANCE FOR SNOW
EXISTS. IF THIS MOISTURE BECOMES ALIGNED...A BETTER SHOT FOR
ACCUMULATING SNOW COULD EXIST SATURDAY. THERE IS SOME OMEGA SHOWN
IN THE LOW LEVEL MOISTURE SATURDAY WHILE THE DGZ IS UNSATURATED.
WILL NEED TO MONITOR THE FREEZING DRIZZLE RISK WITH LATER
FORECASTS.



.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 312 PM EST THU JAN 29 2015

THE STORM ON SUNDAY MOVES THROUGH THE OHIO VALLEY AND WE WILL
CONTINUE TO WATCH FOR THE POTENTIAL OF THE NORTHERN SHIELD OF SNOW
AS IT LOOKS TO JUST GRAZE SOUTHERN LOWER MICHIGAN. COLD AND DRY
NORTHEAST FLOW SHOULD HELP ERODE THE CLOUDS AND CLEARING SUNDAY
NIGHT WILL BRING LOWS IN THE 5 BELOW TO 5 ABOVE RANGE MONDAY MORNING.

SFC RIDGE MOVES EAST ON MONDAY AND ONSHORE FLOW WILL BRING SOME LAKE
EFFECT SNOW SHOWERS INLAND BUT INVERSION HEIGHTS AROUND 5 KFT WILL
LIMIT ACCUMS.

A CLIPPER ALONG AN ARCTIC FRONT ARRIVES LATE TUESDAY INTO TUESDAY
NIGHT AND LAKE ENHANCEMENT IN SOUTHWEST FLOW SHOULD HELP BRING
WIDESPREAD ACCUMULATING SNOW WITH A FEW INCHES IN THE AREA OF BEST
LOW LEVEL CONVERGENCE ACROSS WESTERN AND CENTRAL ZONES. VERY COLD
AIR ARRIVES FOR WEDNESDAY WITH LAKE EFFECT SNOW SHOWERS IN NORTHWEST
FLOW BRINGING LIGHT ACCUMS INTO THURSDAY WHEN SFC RIDGING LOWERS
INVERSION HEIGHTS BLO 3 KFT. THURSDAY IS ALSO PROGGED TO HAVE THE
CORE OF THE COLD AIR MOVING IN WITH 850 MB TEMPS DOWN TO MINUS 25C.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1159 PM EST THU JAN 29 2015

THE TREND OVERNIGHT WILL BE FOR VFR CONDITIONS TO BECOME MORE
WIDESPREAD DUE TO THE ARRIVAL OF A DRIER (AND MUCH COLDER) AIR
MASS FROM THE NORTH. HOWEVER MKG MAY SEE OCNL IFR VSBYS CONTINUE AS
LAKE EFFECT SNOW SHOWERS CLIP THE COAST.

SNOW SHOWERS INLAND FROM LAKE MICHIGAN AT MIDNIGHT ARE EXPECTED
TO END BY 4 AM OR SO AND SEVERAL TERMINALS MAY ACTUALLY SEE SKIES
BECOME SCATTERED BEFORE DAYBREAK. ANY CLEARING THAT TAKES PLACE
LATE TONIGHT AND FRIDAY MORNING WILL PROBABLY FILL BACK IN ON
FRIDAY AFTERNOON. HOWEVER CLOUD BASES SHOULD BE MOSTLY VFR.

GUSTY NORTH-NORTHWEST WINDS FOR A FEW MORE HOURS WILL RESULT IN
CONTINUED LOW LEVEL TURBULENCE... BUT THE WINDS WILL DIMINISH TO
AROUND 10 KTS VERY LATE TONIGHT INTO FRIDAY.

&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...OSTUNO
AVIATION...MEADE
HYDROLOGY...JAM







000
FXUS63 KGRR 300501
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1201 AM EST FRI JAN 30 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 312 PM EST THU JAN 29 2015

LOW PRESSURE WILL TRACK EASTWARD AWAY FROM THE REGION TONIGHT TAKING
MOST OF THE PRECIPITATION WITH IT.  COLD HIGH PRESSURE WILL BUILD IN
FOR FRIDAY LEADING TO MAINLY DRY CONDITIONS. A COLD FRONT WILL
WEAKEN AS IT TRACKS THROUGH LOWER MICHIGAN SATURDAY. LOW PRESSURE
WILL THEN TRACK UP THE OHIO VALLEY FOR SUNDAY. THIS SYSTEM COULD
BRING SOME SNOW TO SOUTHERN PARTS OF LOWER MICHIGAN.

&&

.UPDATE...
ISSUED AT 915 PM EST THU JAN 29 2015

FAIRLY STRONG SHORT WAVE SEEN ON WV IMAGERY OVER NRN WISCONSIN HAS
CAUSED A FLARE UP OF SHSN ACTIVITY ACROSS THE WESTERN CWA THIS
EVENING. VSBYS HAVE FALLEN TO NEAR A MILE AT SOME LOCATIONS AS
SNOW BANDS MOVE SOUTH FROM LAKE SUPERIOR. SHSN SHOULD DIMINISH
SOME AFTER 06Z AS THE WAVE MOVES EAST. UPDATED GRIDS OVER THE
WESTERN CWA TO REFLECT HIGHER POPS THIS EVENING.

UPDATE ISSUED AT 710 PM EST THU JAN 29 2015

STILL GETTING SOME REPORTS OF LIGHT DRIZZLE/FREEZING DRIZZLE
ACCOMPANYING THE LIGHT SNOW SHOWERS THIS EVENING. WILL UPDATE THE
FCST TO INCLUDE THE DRIZZLE FOR A FEW MORE HOURS THIS EVENING...
MAINLY FROM GRR TO THE SOUTH AND EAST. NO IMPACTS EXPECTED GIVEN
VERY LIGHT/PATCHY NATURE OF THE DRIZZLE AND THAT ROADS WERE
ALREADY SIGNIFICANTLY TREATED FROM EARLIER EVENT.

THE DEPARTURE OF THE DEEPER MOISTURE HAS RESULTED IN PROBLEMS
KEEPING A SATURATED DGZ IN THE CLOUD LAYER...THUS THE PATCHY
DRIZZLE. HOWEVER THE ARRIVAL OF THE LOW LEVEL COLD AIR REINTRODUCES
A SATURATED DGZ AT MOST LOCATIONS BY MIDNIGHT PER BUFKIT
OVERVIEWS... IF NOT EARLIER.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 312 PM EST THU JAN 29 2015

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH WHETHER TO EXTEND
THE HEADLINES THIS EVENING.

TEMPERATURES HAVE BEEN CLIMBING AND MOST LOCATIONS ARE NEAR OR ABOVE
FREEZING.  THE PRECIPITATION HAS BEEN WEAKENING.  COLDER CLOUD TOPS
WERE PUSHING EAST OF LANSING SUPPORTING NOT MUCH ADDITIONAL
PRECIPITATION FROM THIS SYSTEM  WHAT DOES FALL SHOULD BE MOSTLY
SNOW...EXCEPT SOME RAIN COULD MIX IN AROUND INTERSTATE 94.  THERE
ENOUGH WARMTH IN THE LOW LEVELS EXISTS TO ALLOW FOR MELTING. ALSO
SPEEDS ON THE HIGHWAY ARE CLOSE TO NORMAL...SUGGESTING THE IMPACT
HAS DIMINISHED FROM THE EARLIER SNOW AND FREEZING RAIN. AS A RESULT
OF ALL THIS THE WINTER WEATHER ADVISORY WILL BE CANCELED SLIGHTLY
EARLY.

NORTHERLY COLD AIR ADVECTION SETS UP OVERNIGHT AND THAT COULD WILL
SUPPORT SOME LAKE EFFECT AS THE COLDER AIR MOVES IN. THIS SETUP
LOOKS WEAK. THE DGZ IS SHOWN TO BE MOIST...BUT SUBSIDENCE IS
NOTED. THIS WILL ACT TO KEEP THE POTENTIAL FOR ACCUMULATIONS LOW. I
WILL FEATURE HIGHEST POPS ALONG THE LAKESHORE.

THE SURFACE HIGH DRIFTS OVER THE AREA FRIDAY NIGHT. GIVEN THE COLD
AIRMASS IN PLACE...WITH LIGHT WINDS AND AT LEAST LIMITED CLOUDS TO
START THE NIGHT...TEMPERATURES WILL END UP AS A WELL BELOW
NORMAL.

WARM AIR ADVECTION DEVELOPS SATURDAY. THIS COULD LEAD TO LAKE
EFFECT/ENHANCED SNOW AS THE FLOW TURNS SOUTHWEST. THE TIMING OF
THE ARRIVAL OF THE MID LEVEL MOISTURE DOES NOT COINCIDE WITH THE
INCREASING LOW LEVEL MOISTURE. THUS ONLY A LIMITED CHANCE FOR SNOW
EXISTS. IF THIS MOISTURE BECOMES ALIGNED...A BETTER SHOT FOR
ACCUMULATING SNOW COULD EXIST SATURDAY. THERE IS SOME OMEGA SHOWN
IN THE LOW LEVEL MOISTURE SATURDAY WHILE THE DGZ IS UNSATURATED.
WILL NEED TO MONITOR THE FREEZING DRIZZLE RISK WITH LATER
FORECASTS.



.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 312 PM EST THU JAN 29 2015

THE STORM ON SUNDAY MOVES THROUGH THE OHIO VALLEY AND WE WILL
CONTINUE TO WATCH FOR THE POTENTIAL OF THE NORTHERN SHIELD OF SNOW
AS IT LOOKS TO JUST GRAZE SOUTHERN LOWER MICHIGAN. COLD AND DRY
NORTHEAST FLOW SHOULD HELP ERODE THE CLOUDS AND CLEARING SUNDAY
NIGHT WILL BRING LOWS IN THE 5 BELOW TO 5 ABOVE RANGE MONDAY MORNING.

SFC RIDGE MOVES EAST ON MONDAY AND ONSHORE FLOW WILL BRING SOME LAKE
EFFECT SNOW SHOWERS INLAND BUT INVERSION HEIGHTS AROUND 5 KFT WILL
LIMIT ACCUMS.

A CLIPPER ALONG AN ARCTIC FRONT ARRIVES LATE TUESDAY INTO TUESDAY
NIGHT AND LAKE ENHANCEMENT IN SOUTHWEST FLOW SHOULD HELP BRING
WIDESPREAD ACCUMULATING SNOW WITH A FEW INCHES IN THE AREA OF BEST
LOW LEVEL CONVERGENCE ACROSS WESTERN AND CENTRAL ZONES. VERY COLD
AIR ARRIVES FOR WEDNESDAY WITH LAKE EFFECT SNOW SHOWERS IN NORTHWEST
FLOW BRINGING LIGHT ACCUMS INTO THURSDAY WHEN SFC RIDGING LOWERS
INVERSION HEIGHTS BLO 3 KFT. THURSDAY IS ALSO PROGGED TO HAVE THE
CORE OF THE COLD AIR MOVING IN WITH 850 MB TEMPS DOWN TO MINUS 25C.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1159 PM EST THU JAN 29 2015

THE TREND OVERNIGHT WILL BE FOR VFR CONDITIONS TO BECOME MORE
WIDESPREAD DUE TO THE ARRIVAL OF A DRIER (AND MUCH COLDER) AIR
MASS FROM THE NORTH. HOWEVER MKG MAY SEE OCNL IFR VSBYS CONTINUE AS
LAKE EFFECT SNOW SHOWERS CLIP THE COAST.

SNOW SHOWERS INLAND FROM LAKE MICHIGAN AT MIDNIGHT ARE EXPECTED
TO END BY 4 AM OR SO AND SEVERAL TERMINALS MAY ACTUALLY SEE SKIES
BECOME SCATTERED BEFORE DAYBREAK. ANY CLEARING THAT TAKES PLACE
LATE TONIGHT AND FRIDAY MORNING WILL PROBABLY FILL BACK IN ON
FRIDAY AFTERNOON. HOWEVER CLOUD BASES SHOULD BE MOSTLY VFR.

GUSTY NORTH-NORTHWEST WINDS FOR A FEW MORE HOURS WILL RESULT IN
CONTINUED LOW LEVEL TURBULENCE... BUT THE WINDS WILL DIMINISH TO
AROUND 10 KTS VERY LATE TONIGHT INTO FRIDAY.

&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...OSTUNO
AVIATION...MEADE
HYDROLOGY...JAM








000
FXUS63 KGRR 300218
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
918 PM EST THU JAN 29 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 312 PM EST THU JAN 29 2015

LOW PRESSURE WILL TRACK EASTWARD AWAY FROM THE REGION TONIGHT TAKING
MOST OF THE PRECIPITATION WITH IT.  COLD HIGH PRESSURE WILL BUILD IN
FOR FRIDAY LEADING TO MAINLY DRY CONDITIONS. A COLD FRONT WILL
WEAKEN AS IT TRACKS THROUGH LOWER MICHIGAN SATURDAY. LOW PRESSURE
WILL THEN TRACK UP THE OHIO VALLEY FOR SUNDAY. THIS SYSTEM COULD
BRING SOME SNOW TO SOUTHERN PARTS OF LOWER MICHIGAN.

&&

.UPDATE...
ISSUED AT 915 PM EST THU JAN 29 2015

FAIRLY STRONG SHORT WAVE SEEN ON WV IMAGERY OVER NRN WISCONSIN HAS
CAUSED A FLARE UP OF SHSN ACTIVITY ACROSS THE WESTERN CWA THIS
EVENING. VSBYS HAVE FALLEN TO NEAR A MILE AT SOME LOCATIONS AS
SNOW BANDS MOVE SOUTH FROM LAKE SUPERIOR. SHSN SHOULD DIMINISH
SOME AFTER 06Z AS THE WAVE MOVES EAST. UPDATED GRIDS OVER THE
WESTERN CWA TO REFLECT HIGHER POPS THIS EVENING.

UPDATE ISSUED AT 710 PM EST THU JAN 29 2015

STILL GETTING SOME REPORTS OF LIGHT DRIZZLE/FREEZING DRIZZLE
ACCOMPANYING THE LIGHT SNOW SHOWERS THIS EVENING. WILL UPDATE THE
FCST TO INCLUDE THE DRIZZLE FOR A FEW MORE HOURS THIS EVENING...
MAINLY FROM GRR TO THE SOUTH AND EAST. NO IMPACTS EXPECTED GIVEN
VERY LIGHT/PATCHY NATURE OF THE DRIZZLE AND THAT ROADS WERE
ALREADY SIGNIFICANTLY TREATED FROM EARLIER EVENT.

THE DEPARTURE OF THE DEEPER MOISTURE HAS RESULTED IN PROBLEMS
KEEPING A SATURATED DGZ IN THE CLOUD LAYER...THUS THE PATCHY
DRIZZLE. HOWEVER THE ARRIVAL OF THE LOW LEVEL COLD AIR REINTRODUCES
A SATURATED DGZ AT MOST LOCATIONS BY MIDNIGHT PER BUFKIT
OVERVIEWS... IF NOT EARLIER.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 312 PM EST THU JAN 29 2015

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH WHETHER TO EXTEND
THE HEADLINES THIS EVENING.

TEMPERATURES HAVE BEEN CLIMBING AND MOST LOCATIONS ARE NEAR OR ABOVE
FREEZING.  THE PRECIPITATION HAS BEEN WEAKENING.  COLDER CLOUD TOPS
WERE PUSHING EAST OF LANSING SUPPORTING NOT MUCH ADDITIONAL
PRECIPITATION FROM THIS SYSTEM  WHAT DOES FALL SHOULD BE MOSTLY
SNOW...EXCEPT SOME RAIN COULD MIX IN AROUND INTERSTATE 94.  THERE
ENOUGH WARMTH IN THE LOW LEVELS EXISTS TO ALLOW FOR MELTING. ALSO
SPEEDS ON THE HIGHWAY ARE CLOSE TO NORMAL...SUGGESTING THE IMPACT
HAS DIMINISHED FROM THE EARLIER SNOW AND FREEZING RAIN. AS A RESULT
OF ALL THIS THE WINTER WEATHER ADVISORY WILL BE CANCELED SLIGHTLY
EARLY.

NORTHERLY COLD AIR ADVECTION SETS UP OVERNIGHT AND THAT COULD WILL
SUPPORT SOME LAKE EFFECT AS THE COLDER AIR MOVES IN. THIS SETUP
LOOKS WEAK. THE DGZ IS SHOWN TO BE MOIST...BUT SUBSIDENCE IS
NOTED. THIS WILL ACT TO KEEP THE POTENTIAL FOR ACCUMULATIONS LOW. I
WILL FEATURE HIGHEST POPS ALONG THE LAKESHORE.

THE SURFACE HIGH DRIFTS OVER THE AREA FRIDAY NIGHT. GIVEN THE COLD
AIRMASS IN PLACE...WITH LIGHT WINDS AND AT LEAST LIMITED CLOUDS TO
START THE NIGHT...TEMPERATURES WILL END UP AS A WELL BELOW
NORMAL.

WARM AIR ADVECTION DEVELOPS SATURDAY. THIS COULD LEAD TO LAKE
EFFECT/ENHANCED SNOW AS THE FLOW TURNS SOUTHWEST. THE TIMING OF
THE ARRIVAL OF THE MID LEVEL MOISTURE DOES NOT COINCIDE WITH THE
INCREASING LOW LEVEL MOISTURE. THUS ONLY A LIMITED CHANCE FOR SNOW
EXISTS. IF THIS MOISTURE BECOMES ALIGNED...A BETTER SHOT FOR
ACCUMULATING SNOW COULD EXIST SATURDAY. THERE IS SOME OMEGA SHOWN
IN THE LOW LEVEL MOISTURE SATURDAY WHILE THE DGZ IS UNSATURATED.
WILL NEED TO MONITOR THE FREEZING DRIZZLE RISK WITH LATER
FORECASTS.



.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 312 PM EST THU JAN 29 2015

THE STORM ON SUNDAY MOVES THROUGH THE OHIO VALLEY AND WE WILL
CONTINUE TO WATCH FOR THE POTENTIAL OF THE NORTHERN SHIELD OF SNOW
AS IT LOOKS TO JUST GRAZE SOUTHERN LOWER MICHIGAN. COLD AND DRY
NORTHEAST FLOW SHOULD HELP ERODE THE CLOUDS AND CLEARING SUNDAY
NIGHT WILL BRING LOWS IN THE 5 BELOW TO 5 ABOVE RANGE MONDAY MORNING.

SFC RIDGE MOVES EAST ON MONDAY AND ONSHORE FLOW WILL BRING SOME LAKE
EFFECT SNOW SHOWERS INLAND BUT INVERSION HEIGHTS AROUND 5 KFT WILL
LIMIT ACCUMS.

A CLIPPER ALONG AN ARCTIC FRONT ARRIVES LATE TUESDAY INTO TUESDAY
NIGHT AND LAKE ENHANCEMENT IN SOUTHWEST FLOW SHOULD HELP BRING
WIDESPREAD ACCUMULATING SNOW WITH A FEW INCHES IN THE AREA OF BEST
LOW LEVEL CONVERGENCE ACROSS WESTERN AND CENTRAL ZONES. VERY COLD
AIR ARRIVES FOR WEDNESDAY WITH LAKE EFFECT SNOW SHOWERS IN NORTHWEST
FLOW BRINGING LIGHT ACCUMS INTO THURSDAY WHEN SFC RIDGING LOWERS
INVERSION HEIGHTS BLO 3 KFT. THURSDAY IS ALSO PROGGED TO HAVE THE
CORE OF THE COLD AIR MOVING IN WITH 850 MB TEMPS DOWN TO MINUS 25C.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 710 PM EST THU JAN 29 2015

WIDESPREAD MVFR CIGS BETWEEN 1500 AND 2500 FT WILL PREVAIL THIS
EVENING ALONG WITH SOME FLURRIES AND PATCHY LIGHT DRIZZLE/FREEZING
DRIZZLE. ANY VSBYS RESTRICTIONS FROM THIS LIGHT PRECIP SHOULD
ONLY BE 3-5SM FOR BRIEF TIMES. AN ICING THREAT STILL EXIST THIS
EVENING FROM THE SFC TO 7000 FT... AND THAT WILL END AFTER
MIDNIGHT.

CONDITIONS ARE EXPECTED TO IMPROVE TO VFR AT MOST LOCATIONS LATE
TONIGHT INTO FRIDAY... WITH THE PERHAPS THE EXCEPTION OF MKG WHERE
SOME LIGHT LAKE EFFECT SNOW SHOWERS MAY STILL OCCUR. GUSTY
NORTHWEST WINDS THIS EVENING WILL RESULT IN SOME LOW LEVEL
TURBULENCE... BUT THE WINDS WILL DIMINISH TO AROUND 10 KTS VERY
LATE TONIGHT INTO FRIDAY.


&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...OSTUNO
AVIATION...MEADE
HYDROLOGY...JAM








000
FXUS63 KGRR 300218
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
918 PM EST THU JAN 29 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 312 PM EST THU JAN 29 2015

LOW PRESSURE WILL TRACK EASTWARD AWAY FROM THE REGION TONIGHT TAKING
MOST OF THE PRECIPITATION WITH IT.  COLD HIGH PRESSURE WILL BUILD IN
FOR FRIDAY LEADING TO MAINLY DRY CONDITIONS. A COLD FRONT WILL
WEAKEN AS IT TRACKS THROUGH LOWER MICHIGAN SATURDAY. LOW PRESSURE
WILL THEN TRACK UP THE OHIO VALLEY FOR SUNDAY. THIS SYSTEM COULD
BRING SOME SNOW TO SOUTHERN PARTS OF LOWER MICHIGAN.

&&

.UPDATE...
ISSUED AT 915 PM EST THU JAN 29 2015

FAIRLY STRONG SHORT WAVE SEEN ON WV IMAGERY OVER NRN WISCONSIN HAS
CAUSED A FLARE UP OF SHSN ACTIVITY ACROSS THE WESTERN CWA THIS
EVENING. VSBYS HAVE FALLEN TO NEAR A MILE AT SOME LOCATIONS AS
SNOW BANDS MOVE SOUTH FROM LAKE SUPERIOR. SHSN SHOULD DIMINISH
SOME AFTER 06Z AS THE WAVE MOVES EAST. UPDATED GRIDS OVER THE
WESTERN CWA TO REFLECT HIGHER POPS THIS EVENING.

UPDATE ISSUED AT 710 PM EST THU JAN 29 2015

STILL GETTING SOME REPORTS OF LIGHT DRIZZLE/FREEZING DRIZZLE
ACCOMPANYING THE LIGHT SNOW SHOWERS THIS EVENING. WILL UPDATE THE
FCST TO INCLUDE THE DRIZZLE FOR A FEW MORE HOURS THIS EVENING...
MAINLY FROM GRR TO THE SOUTH AND EAST. NO IMPACTS EXPECTED GIVEN
VERY LIGHT/PATCHY NATURE OF THE DRIZZLE AND THAT ROADS WERE
ALREADY SIGNIFICANTLY TREATED FROM EARLIER EVENT.

THE DEPARTURE OF THE DEEPER MOISTURE HAS RESULTED IN PROBLEMS
KEEPING A SATURATED DGZ IN THE CLOUD LAYER...THUS THE PATCHY
DRIZZLE. HOWEVER THE ARRIVAL OF THE LOW LEVEL COLD AIR REINTRODUCES
A SATURATED DGZ AT MOST LOCATIONS BY MIDNIGHT PER BUFKIT
OVERVIEWS... IF NOT EARLIER.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 312 PM EST THU JAN 29 2015

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH WHETHER TO EXTEND
THE HEADLINES THIS EVENING.

TEMPERATURES HAVE BEEN CLIMBING AND MOST LOCATIONS ARE NEAR OR ABOVE
FREEZING.  THE PRECIPITATION HAS BEEN WEAKENING.  COLDER CLOUD TOPS
WERE PUSHING EAST OF LANSING SUPPORTING NOT MUCH ADDITIONAL
PRECIPITATION FROM THIS SYSTEM  WHAT DOES FALL SHOULD BE MOSTLY
SNOW...EXCEPT SOME RAIN COULD MIX IN AROUND INTERSTATE 94.  THERE
ENOUGH WARMTH IN THE LOW LEVELS EXISTS TO ALLOW FOR MELTING. ALSO
SPEEDS ON THE HIGHWAY ARE CLOSE TO NORMAL...SUGGESTING THE IMPACT
HAS DIMINISHED FROM THE EARLIER SNOW AND FREEZING RAIN. AS A RESULT
OF ALL THIS THE WINTER WEATHER ADVISORY WILL BE CANCELED SLIGHTLY
EARLY.

NORTHERLY COLD AIR ADVECTION SETS UP OVERNIGHT AND THAT COULD WILL
SUPPORT SOME LAKE EFFECT AS THE COLDER AIR MOVES IN. THIS SETUP
LOOKS WEAK. THE DGZ IS SHOWN TO BE MOIST...BUT SUBSIDENCE IS
NOTED. THIS WILL ACT TO KEEP THE POTENTIAL FOR ACCUMULATIONS LOW. I
WILL FEATURE HIGHEST POPS ALONG THE LAKESHORE.

THE SURFACE HIGH DRIFTS OVER THE AREA FRIDAY NIGHT. GIVEN THE COLD
AIRMASS IN PLACE...WITH LIGHT WINDS AND AT LEAST LIMITED CLOUDS TO
START THE NIGHT...TEMPERATURES WILL END UP AS A WELL BELOW
NORMAL.

WARM AIR ADVECTION DEVELOPS SATURDAY. THIS COULD LEAD TO LAKE
EFFECT/ENHANCED SNOW AS THE FLOW TURNS SOUTHWEST. THE TIMING OF
THE ARRIVAL OF THE MID LEVEL MOISTURE DOES NOT COINCIDE WITH THE
INCREASING LOW LEVEL MOISTURE. THUS ONLY A LIMITED CHANCE FOR SNOW
EXISTS. IF THIS MOISTURE BECOMES ALIGNED...A BETTER SHOT FOR
ACCUMULATING SNOW COULD EXIST SATURDAY. THERE IS SOME OMEGA SHOWN
IN THE LOW LEVEL MOISTURE SATURDAY WHILE THE DGZ IS UNSATURATED.
WILL NEED TO MONITOR THE FREEZING DRIZZLE RISK WITH LATER
FORECASTS.



.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 312 PM EST THU JAN 29 2015

THE STORM ON SUNDAY MOVES THROUGH THE OHIO VALLEY AND WE WILL
CONTINUE TO WATCH FOR THE POTENTIAL OF THE NORTHERN SHIELD OF SNOW
AS IT LOOKS TO JUST GRAZE SOUTHERN LOWER MICHIGAN. COLD AND DRY
NORTHEAST FLOW SHOULD HELP ERODE THE CLOUDS AND CLEARING SUNDAY
NIGHT WILL BRING LOWS IN THE 5 BELOW TO 5 ABOVE RANGE MONDAY MORNING.

SFC RIDGE MOVES EAST ON MONDAY AND ONSHORE FLOW WILL BRING SOME LAKE
EFFECT SNOW SHOWERS INLAND BUT INVERSION HEIGHTS AROUND 5 KFT WILL
LIMIT ACCUMS.

A CLIPPER ALONG AN ARCTIC FRONT ARRIVES LATE TUESDAY INTO TUESDAY
NIGHT AND LAKE ENHANCEMENT IN SOUTHWEST FLOW SHOULD HELP BRING
WIDESPREAD ACCUMULATING SNOW WITH A FEW INCHES IN THE AREA OF BEST
LOW LEVEL CONVERGENCE ACROSS WESTERN AND CENTRAL ZONES. VERY COLD
AIR ARRIVES FOR WEDNESDAY WITH LAKE EFFECT SNOW SHOWERS IN NORTHWEST
FLOW BRINGING LIGHT ACCUMS INTO THURSDAY WHEN SFC RIDGING LOWERS
INVERSION HEIGHTS BLO 3 KFT. THURSDAY IS ALSO PROGGED TO HAVE THE
CORE OF THE COLD AIR MOVING IN WITH 850 MB TEMPS DOWN TO MINUS 25C.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 710 PM EST THU JAN 29 2015

WIDESPREAD MVFR CIGS BETWEEN 1500 AND 2500 FT WILL PREVAIL THIS
EVENING ALONG WITH SOME FLURRIES AND PATCHY LIGHT DRIZZLE/FREEZING
DRIZZLE. ANY VSBYS RESTRICTIONS FROM THIS LIGHT PRECIP SHOULD
ONLY BE 3-5SM FOR BRIEF TIMES. AN ICING THREAT STILL EXIST THIS
EVENING FROM THE SFC TO 7000 FT... AND THAT WILL END AFTER
MIDNIGHT.

CONDITIONS ARE EXPECTED TO IMPROVE TO VFR AT MOST LOCATIONS LATE
TONIGHT INTO FRIDAY... WITH THE PERHAPS THE EXCEPTION OF MKG WHERE
SOME LIGHT LAKE EFFECT SNOW SHOWERS MAY STILL OCCUR. GUSTY
NORTHWEST WINDS THIS EVENING WILL RESULT IN SOME LOW LEVEL
TURBULENCE... BUT THE WINDS WILL DIMINISH TO AROUND 10 KTS VERY
LATE TONIGHT INTO FRIDAY.


&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...93
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...OSTUNO
AVIATION...MEADE
HYDROLOGY...JAM







000
FXUS63 KGRR 300010
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
710 PM EST THU JAN 29 2015

LATEST UPDATE...
UPDATE/AVIATION

.SYNOPSIS...
ISSUED AT 312 PM EST THU JAN 29 2015

LOW PRESSURE WILL TRACK EASTWARD AWAY FROM THE REGION TONIGHT TAKING
MOST OF THE PRECIPITATION WITH IT.  COLD HIGH PRESSURE WILL BUILD IN
FOR FRIDAY LEADING TO MAINLY DRY CONDITIONS. A COLD FRONT WILL
WEAKEN AS IT TRACKS THROUGH LOWER MICHIGAN SATURDAY. LOW PRESSURE
WILL THEN TRACK UP THE OHIO VALLEY FOR SUNDAY. THIS SYSTEM COULD
BRING SOME SNOW TO SOUTHERN PARTS OF LOWER MICHIGAN.

&&

.UPDATE...
ISSUED AT 710 PM EST THU JAN 29 2015

STILL GETTING SOME REPORTS OF LIGHT DRIZZLE/FREEZING DRIZZLE
ACCOMPANYING THE LIGHT SNOW SHOWERS THIS EVENING. WILL UPDATE THE
FCST TO INCLUDE THE DRIZZLE FOR A FEW MORE HOURS THIS EVENING...
MAINLY FROM GRR TO THE SOUTH AND EAST. NO IMPACTS EXPECTED GIVEN
VERY LIGHT/PATCHY NATURE OF THE DRIZZLE AND THAT ROADS WERE
ALREADY SIGNIFICANTLY TREATED FROM EARLIER EVENT.

THE DEPARTURE OF THE DEEPER MOISTURE HAS RESULTED IN PROBLEMS
KEEPING A SATURATED DGZ IN THE CLOUD LAYER...THUS THE PATCHY
DRIZZLE. HOWEVER THE ARRIVAL OF THE LOW LEVEL COLD AIR REINTRODUCES
A SATURATED DGZ AT MOST LOCATIONS BY MIDNIGHT PER BUFKIT
OVERVIEWS... IF NOT EARLIER.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 312 PM EST THU JAN 29 2015

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH WHETHER TO EXTEND
THE HEADLINES THIS EVENING.

TEMPERATURES HAVE BEEN CLIMBING AND MOST LOCATIONS ARE NEAR OR ABOVE
FREEZING.  THE PRECIPITATION HAS BEEN WEAKENING.  COLDER CLOUD TOPS
WERE PUSHING EAST OF LANSING SUPPORTING NOT MUCH ADDITIONAL
PRECIPITATION FROM THIS SYSTEM  WHAT DOES FALL SHOULD BE MOSTLY
SNOW...EXCEPT SOME RAIN COULD MIX IN AROUND INTERSTATE 94.  THERE
ENOUGH WARMTH IN THE LOW LEVELS EXISTS TO ALLOW FOR MELTING. ALSO
SPEEDS ON THE HIGHWAY ARE CLOSE TO NORMAL...SUGGESTING THE IMPACT
HAS DIMINISHED FROM THE EARLIER SNOW AND FREEZING RAIN. AS A RESULT
OF ALL THIS THE WINTER WEATHER ADVISORY WILL BE CANCELED SLIGHTLY
EARLY.

NORTHERLY COLD AIR ADVECTION SETS UP OVERNIGHT AND THAT COULD WILL
SUPPORT SOME LAKE EFFECT AS THE COLDER AIR MOVES IN. THIS SETUP
LOOKS WEAK. THE DGZ IS SHOWN TO BE MOIST...BUT SUBSIDENCE IS
NOTED. THIS WILL ACT TO KEEP THE POTENTIAL FOR ACCUMULATIONS LOW. I
WILL FEATURE HIGHEST POPS ALONG THE LAKESHORE.

THE SURFACE HIGH DRIFTS OVER THE AREA FRIDAY NIGHT. GIVEN THE COLD
AIRMASS IN PLACE...WITH LIGHT WINDS AND AT LEAST LIMITED CLOUDS TO
START THE NIGHT...TEMPERATURES WILL END UP AS A WELL BELOW
NORMAL.

WARM AIR ADVECTION DEVELOPS SATURDAY. THIS COULD LEAD TO LAKE
EFFECT/ENHANCED SNOW AS THE FLOW TURNS SOUTHWEST. THE TIMING OF
THE ARRIVAL OF THE MID LEVEL MOISTURE DOES NOT COINCIDE WITH THE
INCREASING LOW LEVEL MOISTURE. THUS ONLY A LIMITED CHANCE FOR SNOW
EXISTS. IF THIS MOISTURE BECOMES ALIGNED...A BETTER SHOT FOR
ACCUMULATING SNOW COULD EXIST SATURDAY. THERE IS SOME OMEGA SHOWN
IN THE LOW LEVEL MOISTURE SATURDAY WHILE THE DGZ IS UNSATURATED.
WILL NEED TO MONITOR THE FREEZING DRIZZLE RISK WITH LATER
FORECASTS.



.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 312 PM EST THU JAN 29 2015

THE STORM ON SUNDAY MOVES THROUGH THE OHIO VALLEY AND WE WILL
CONTINUE TO WATCH FOR THE POTENTIAL OF THE NORTHERN SHIELD OF SNOW
AS IT LOOKS TO JUST GRAZE SOUTHERN LOWER MICHIGAN. COLD AND DRY
NORTHEAST FLOW SHOULD HELP ERODE THE CLOUDS AND CLEARING SUNDAY
NIGHT WILL BRING LOWS IN THE 5 BELOW TO 5 ABOVE RANGE MONDAY MORNING.

SFC RIDGE MOVES EAST ON MONDAY AND ONSHORE FLOW WILL BRING SOME LAKE
EFFECT SNOW SHOWERS INLAND BUT INVERSION HEIGHTS AROUND 5 KFT WILL
LIMIT ACCUMS.

A CLIPPER ALONG AN ARCTIC FRONT ARRIVES LATE TUESDAY INTO TUESDAY
NIGHT AND LAKE ENHANCEMENT IN SOUTHWEST FLOW SHOULD HELP BRING
WIDESPREAD ACCUMULATING SNOW WITH A FEW INCHES IN THE AREA OF BEST
LOW LEVEL CONVERGENCE ACROSS WESTERN AND CENTRAL ZONES. VERY COLD
AIR ARRIVES FOR WEDNESDAY WITH LAKE EFFECT SNOW SHOWERS IN NORTHWEST
FLOW BRINGING LIGHT ACCUMS INTO THURSDAY WHEN SFC RIDGING LOWERS
INVERSION HEIGHTS BLO 3 KFT. THURSDAY IS ALSO PROGGED TO HAVE THE
CORE OF THE COLD AIR MOVING IN WITH 850 MB TEMPS DOWN TO MINUS 25C.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 710 PM EST THU JAN 29 2015

WIDESPREAD MVFR CIGS BETWEEN 1500 AND 2500 FT WILL PREVAIL THIS
EVENING ALONG WITH SOME FLURRIES AND PATCHY LIGHT DRIZZLE/FREEZING
DRIZZLE. ANY VSBYS RESTRICTIONS FROM THIS LIGHT PRECIP SHOULD
ONLY BE 3-5SM FOR BRIEF TIMES. AN ICING THREAT STILL EXIST THIS
EVENING FROM THE SFC TO 7000 FT... AND THAT WILL END AFTER
MIDNIGHT.

CONDITIONS ARE EXPECTED TO IMPROVE TO VFR AT MOST LOCATIONS LATE
TONIGHT INTO FRIDAY... WITH THE PERHAPS THE EXCEPTION OF MKG WHERE
SOME LIGHT LAKE EFFECT SNOW SHOWERS MAY STILL OCCUR. GUSTY
NORTHWEST WINDS THIS EVENING WILL RESULT IN SOME LOW LEVEL
TURBULENCE... BUT THE WINDS WILL DIMINISH TO AROUND 10 KTS VERY
LATE TONIGHT INTO FRIDAY.


&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...MEADE
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...OSTUNO
AVIATION...MEADE
HYDROLOGY...JAM







000
FXUS63 KGRR 300010
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
710 PM EST THU JAN 29 2015

LATEST UPDATE...
UPDATE/AVIATION

.SYNOPSIS...
ISSUED AT 312 PM EST THU JAN 29 2015

LOW PRESSURE WILL TRACK EASTWARD AWAY FROM THE REGION TONIGHT TAKING
MOST OF THE PRECIPITATION WITH IT.  COLD HIGH PRESSURE WILL BUILD IN
FOR FRIDAY LEADING TO MAINLY DRY CONDITIONS. A COLD FRONT WILL
WEAKEN AS IT TRACKS THROUGH LOWER MICHIGAN SATURDAY. LOW PRESSURE
WILL THEN TRACK UP THE OHIO VALLEY FOR SUNDAY. THIS SYSTEM COULD
BRING SOME SNOW TO SOUTHERN PARTS OF LOWER MICHIGAN.

&&

.UPDATE...
ISSUED AT 710 PM EST THU JAN 29 2015

STILL GETTING SOME REPORTS OF LIGHT DRIZZLE/FREEZING DRIZZLE
ACCOMPANYING THE LIGHT SNOW SHOWERS THIS EVENING. WILL UPDATE THE
FCST TO INCLUDE THE DRIZZLE FOR A FEW MORE HOURS THIS EVENING...
MAINLY FROM GRR TO THE SOUTH AND EAST. NO IMPACTS EXPECTED GIVEN
VERY LIGHT/PATCHY NATURE OF THE DRIZZLE AND THAT ROADS WERE
ALREADY SIGNIFICANTLY TREATED FROM EARLIER EVENT.

THE DEPARTURE OF THE DEEPER MOISTURE HAS RESULTED IN PROBLEMS
KEEPING A SATURATED DGZ IN THE CLOUD LAYER...THUS THE PATCHY
DRIZZLE. HOWEVER THE ARRIVAL OF THE LOW LEVEL COLD AIR REINTRODUCES
A SATURATED DGZ AT MOST LOCATIONS BY MIDNIGHT PER BUFKIT
OVERVIEWS... IF NOT EARLIER.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 312 PM EST THU JAN 29 2015

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH WHETHER TO EXTEND
THE HEADLINES THIS EVENING.

TEMPERATURES HAVE BEEN CLIMBING AND MOST LOCATIONS ARE NEAR OR ABOVE
FREEZING.  THE PRECIPITATION HAS BEEN WEAKENING.  COLDER CLOUD TOPS
WERE PUSHING EAST OF LANSING SUPPORTING NOT MUCH ADDITIONAL
PRECIPITATION FROM THIS SYSTEM  WHAT DOES FALL SHOULD BE MOSTLY
SNOW...EXCEPT SOME RAIN COULD MIX IN AROUND INTERSTATE 94.  THERE
ENOUGH WARMTH IN THE LOW LEVELS EXISTS TO ALLOW FOR MELTING. ALSO
SPEEDS ON THE HIGHWAY ARE CLOSE TO NORMAL...SUGGESTING THE IMPACT
HAS DIMINISHED FROM THE EARLIER SNOW AND FREEZING RAIN. AS A RESULT
OF ALL THIS THE WINTER WEATHER ADVISORY WILL BE CANCELED SLIGHTLY
EARLY.

NORTHERLY COLD AIR ADVECTION SETS UP OVERNIGHT AND THAT COULD WILL
SUPPORT SOME LAKE EFFECT AS THE COLDER AIR MOVES IN. THIS SETUP
LOOKS WEAK. THE DGZ IS SHOWN TO BE MOIST...BUT SUBSIDENCE IS
NOTED. THIS WILL ACT TO KEEP THE POTENTIAL FOR ACCUMULATIONS LOW. I
WILL FEATURE HIGHEST POPS ALONG THE LAKESHORE.

THE SURFACE HIGH DRIFTS OVER THE AREA FRIDAY NIGHT. GIVEN THE COLD
AIRMASS IN PLACE...WITH LIGHT WINDS AND AT LEAST LIMITED CLOUDS TO
START THE NIGHT...TEMPERATURES WILL END UP AS A WELL BELOW
NORMAL.

WARM AIR ADVECTION DEVELOPS SATURDAY. THIS COULD LEAD TO LAKE
EFFECT/ENHANCED SNOW AS THE FLOW TURNS SOUTHWEST. THE TIMING OF
THE ARRIVAL OF THE MID LEVEL MOISTURE DOES NOT COINCIDE WITH THE
INCREASING LOW LEVEL MOISTURE. THUS ONLY A LIMITED CHANCE FOR SNOW
EXISTS. IF THIS MOISTURE BECOMES ALIGNED...A BETTER SHOT FOR
ACCUMULATING SNOW COULD EXIST SATURDAY. THERE IS SOME OMEGA SHOWN
IN THE LOW LEVEL MOISTURE SATURDAY WHILE THE DGZ IS UNSATURATED.
WILL NEED TO MONITOR THE FREEZING DRIZZLE RISK WITH LATER
FORECASTS.



.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 312 PM EST THU JAN 29 2015

THE STORM ON SUNDAY MOVES THROUGH THE OHIO VALLEY AND WE WILL
CONTINUE TO WATCH FOR THE POTENTIAL OF THE NORTHERN SHIELD OF SNOW
AS IT LOOKS TO JUST GRAZE SOUTHERN LOWER MICHIGAN. COLD AND DRY
NORTHEAST FLOW SHOULD HELP ERODE THE CLOUDS AND CLEARING SUNDAY
NIGHT WILL BRING LOWS IN THE 5 BELOW TO 5 ABOVE RANGE MONDAY MORNING.

SFC RIDGE MOVES EAST ON MONDAY AND ONSHORE FLOW WILL BRING SOME LAKE
EFFECT SNOW SHOWERS INLAND BUT INVERSION HEIGHTS AROUND 5 KFT WILL
LIMIT ACCUMS.

A CLIPPER ALONG AN ARCTIC FRONT ARRIVES LATE TUESDAY INTO TUESDAY
NIGHT AND LAKE ENHANCEMENT IN SOUTHWEST FLOW SHOULD HELP BRING
WIDESPREAD ACCUMULATING SNOW WITH A FEW INCHES IN THE AREA OF BEST
LOW LEVEL CONVERGENCE ACROSS WESTERN AND CENTRAL ZONES. VERY COLD
AIR ARRIVES FOR WEDNESDAY WITH LAKE EFFECT SNOW SHOWERS IN NORTHWEST
FLOW BRINGING LIGHT ACCUMS INTO THURSDAY WHEN SFC RIDGING LOWERS
INVERSION HEIGHTS BLO 3 KFT. THURSDAY IS ALSO PROGGED TO HAVE THE
CORE OF THE COLD AIR MOVING IN WITH 850 MB TEMPS DOWN TO MINUS 25C.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 710 PM EST THU JAN 29 2015

WIDESPREAD MVFR CIGS BETWEEN 1500 AND 2500 FT WILL PREVAIL THIS
EVENING ALONG WITH SOME FLURRIES AND PATCHY LIGHT DRIZZLE/FREEZING
DRIZZLE. ANY VSBYS RESTRICTIONS FROM THIS LIGHT PRECIP SHOULD
ONLY BE 3-5SM FOR BRIEF TIMES. AN ICING THREAT STILL EXIST THIS
EVENING FROM THE SFC TO 7000 FT... AND THAT WILL END AFTER
MIDNIGHT.

CONDITIONS ARE EXPECTED TO IMPROVE TO VFR AT MOST LOCATIONS LATE
TONIGHT INTO FRIDAY... WITH THE PERHAPS THE EXCEPTION OF MKG WHERE
SOME LIGHT LAKE EFFECT SNOW SHOWERS MAY STILL OCCUR. GUSTY
NORTHWEST WINDS THIS EVENING WILL RESULT IN SOME LOW LEVEL
TURBULENCE... BUT THE WINDS WILL DIMINISH TO AROUND 10 KTS VERY
LATE TONIGHT INTO FRIDAY.


&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...MEADE
SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...OSTUNO
AVIATION...MEADE
HYDROLOGY...JAM








000
FXUS63 KGRR 292027
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
327 PM EST THU JAN 29 2015

LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM

.SYNOPSIS...
ISSUED AT 312 PM EST THU JAN 29 2015

LOW PRESSURE WILL TRACK EASTWARD AWAY FROM THE REGION TONIGHT TAKING
MOST OF THE PRECIPITATION WITH IT.  COLD HIGH PRESSURE WILL BUILD IN
FOR FRIDAY LEADING TO MAINLY DRY CONDITIONS. A COLD FRONT WILL
WEAKEN AS IT TRACKS THROUGH LOWER MICHIGAN SATURDAY. LOW PRESSURE
WILL THEN TRACK UP THE OHIO VALLEY FOR SUNDAY. THIS SYSTEM COULD
BRING SOME SNOW TO SOUTHERN PARTS OF LOWER MICHIGAN.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 312 PM EST THU JAN 29 2015

THE MAIN CHALLENGE IN THE SHORT TERM DEALS WITH WHETHER TO EXTEND
THE HEADLINES THIS EVENING.

TEMPERATURES HAVE BEEN CLIMBING AND MOST LOCATIONS ARE NEAR OR ABOVE
FREEZING.  THE PRECIPITATION HAS BEEN WEAKENING.  COLDER CLOUD TOPS
WERE PUSHING EAST OF LANSING SUPPORTING NOT MUCH ADDITIONAL
PRECIPITATION FROM THIS SYSTEM  WHAT DOES FALL SHOULD BE MOSTLY
SNOW...EXCEPT SOME RAIN COULD MIX IN AROUND INTERSTATE 94.  THERE
ENOUGH WARMTH IN THE LOW LEVELS EXISTS TO ALLOW FOR MELTING. ALSO
SPEEDS ON THE HIGHWAY ARE CLOSE TO NORMAL...SUGGESTING THE IMPACT
HAS DIMINISHED FROM THE EARLIER SNOW AND FREEZING RAIN. AS A RESULT
OF ALL THIS THE WINTER WEATHER ADVISORY WILL BE CANCELLED SLIGHTLY
EARLY.

NORTHERLY COLD AIR ADVECTION SETS UP OVERNIGHT AND THAT COULD WILL
SUPPORT SOME LAKE EFFECT AS THE COLDER AIR MOVES IN. THIS SETUP
LOOKS WEAK. THE DGZ IS SHOWN TO BE MOIST...BUT SUBSIDENCE IS
NOTED. THIS WILL ACT TO KEEP THE POTENTIAL FOR ACCUMULATIONS LOW. I
WILL FEATURE HIGHEST POPS ALONG THE LAKESHORE.

THE SURFACE HIGH DRIFTS OVER THE AREA FRIDAY NIGHT. GIVEN THE COLD
AIRMASS IN PLACE...WITH LIGHT WINDS AND AT LEAST LIMITED CLOUDS TO
START THE NIGHT...TEMPERATURES WILL END UP AS A WELL BELOW
NORMAL.

WARM AIR ADVECTION DEVELOPS SATURDAY. THIS COULD LEAD TO LAKE
EFFECT/ENHANCED SNOW AS THE FLOW TURNS SOUTHWEST. THE TIMING OF
THE ARRIVAL OF THE MID LEVEL MOISTURE DOES NOT COINCIDE WITH THE
INCREASING LOW LEVEL MOISTURE. THUS ONLY A LIMITED CHANCE FOR SNOW
EXISTS. IF THIS MOISTURE BECOMES ALIGNED...A BETTER SHOT FOR
ACCUMULATING SNOW COULD EXIST SATURDAY. THERE IS SOME OMEGA SHOWN
IN THE LOW LEVEL MOISTURE SATURDAY WHILE THE DGZ IS UNSATURATED.
WILL NEED TO MONITOR THE FREEZING DRIZZLE RISK WITH LATER
FORECASTS.





.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 312 PM EST THU JAN 29 2015

THE STORM ON SUNDAY MOVES THROUGH THE OHIO VALLEY AND WE WILL
CONTINUE TO WATCH FOR THE POTENTIAL OF THE NORTHERN SHIELD OF SNOW
AS IT LOOKS TO JUST GRAZE SOUTHERN LOWER MICHIGAN. COLD AND DRY
NORTHEAST FLOW SHOULD HELP ERODE THE CLOUDS AND CLEARING SUNDAY
NIGHT WILL BRING LOWS IN THE 5 BELOW TO 5 ABOVE RANGE MONDAY MORNING.

SFC RIDGE MOVES EAST ON MONDAY AND ONSHORE FLOW WILL BRING SOME LAKE
EFFECT SNOW SHOWERS INLAND BUT INVERSION HEIGHTS AROUND 5 KFT WILL
LIMIT ACCUMS.

A CLIPPER ALONG AN ARCTIC FRONT ARRIVES LATE TUESDAY INTO TUESDAY
NIGHT AND LAKE ENHANCEMENT IN SOUTHWEST FLOW SHOULD HELP BRING
WIDESPREAD ACCUMULATING SNOW WITH A FEW INCHES IN THE AREA OF BEST
LOW LEVEL CONVERGENCE ACROSS WESTERN AND CENTRAL ZONES. VERY COLD
AIR ARRIVES FOR WEDNESDAY WITH LAKE EFFECT SNOW SHOWERS IN NORTHWEST
FLOW BRINGING LIGHT ACCUMS INTO THURSDAY WHEN SFC RIDGING LOWERS
INVERSION HEIGHTS BLO 3 KFT. THURSDAY IS ALSO PROGGED TO HAVE THE
CORE OF THE COLD AIR MOVING IN WITH 850 MB TEMPS DOWN TO MINUS 25C.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 120 PM EST THU JAN 29 2015

IFR CONDITIONS SHOULD IMPROVE TO MVFR AS LIGHT SNOW WILL BE ENDING
BY LATE AFTERNOON EXCEPT NEAR LAKE MICHIGAN WHERE SOME SNOW SHOWERS
WILL BE POSSIBLE INTO THIS EVENING. THEN EXPECT MVFR CONDITIONS TO
PREVAIL OVERNIGHT AS A STRATUS DECK WITH BASES AROUND 2500 FEET
AGL PERSISTS INTO FRIDAY MORNING. NORTHEAST WINDS WILL GUST OVER
20 KNOTS AT TIMES.


&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

SYNOPSIS...MJS
SHORT TERM...MJS
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...JAM








000
FXUS63 KGRR 291821
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
121 PM EST THU JAN 29 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 318 AM EST THU JAN 29 2015

A WINTRY MIX WILL CONTINUE TODAY.  SOME AREAS MAY SEE UP TO A TENTH
OF INCH OF ICE BY MID DAY.  THE PRECIPITATION WILL BE CHANGING OVER
TO MOSTLY SNOW BY THIS AFTERNOON.  AND AS COLDER AIR MOVES IN...SOME
LAKE EFFECT SNOW WILL DEVELOP TONIGHT AND CONTINUE INTO FRIDAY.
HOWEVER SNOW ACCUMULATIONS ARE EXPECTED TO BE LIGHT...GENERALLY AN
INCH OR TWO.  AFTER HIGHS IN THE 30S TODAY...IT WILL COOL TO ONLY
AROUND 20 BY FRIDAY.

A STORM SYSTEM WILL MOVE SOUTH OF THE AREA SUNDAY AND MONDAY.  WE
WILL HAVE TO KEEP AN EYE ON THIS AS IT MAY GIVE SOUTHWEST MICHIGAN
MORE SNOW.  EITHER WAY...IT WILL GET MUCH COLDER INTO NEXT WEEK WITH
DAYTIME HIGHS ONLY IN THE TEENS SUNDAY THROUGH WEDNESDAY.

&&

.UPDATE...
ISSUED AT 949 AM EST THU JAN 29 2015

UPDATED THE FORECAST TO INCLUDE SOME FREEZING RAIN EVEN FOR
NORTHEAST COUNTIES. REED CITY CAME IN WITH FREEZING RAIN RECENTLY
AS THE DGZ BECAME UNSATURATED. OVERALL PRIMARILY SNOW IS EXPECTED
FOR THE NORTHEAST COUNTIES INCLUDING BIG RAPIDS AND HARRISON.

UPDATE ISSUED AT 759 AM EST THU JAN 29 2015

WE ARE IN THE EXPECTED LULL BETWEEN FREEZING RAIN THAT EXITED EAST
AND AN UPSTREAM BATCH OF PRECIPITATION CROSSING WISCONSIN AND
NORTHERN LOWER MI. THIS UPSTREAM PRECIPITATION IS ASSOCIATED WITH
AN UPPER DEFORMATION ZONE AND EXPECTED TO REMAIN ALL SNOW OVER
CENTRAL AND NORTHERN LOWER MI. FARTHER SOUTH THE FORECAST WILL BE
MORE COMPLEX. THE SURFACE LOW CURRENTLY NEAR CHICAGO IS EXPECTED
TO MOVE EAST ACROSS NRN IN/OH TODAY...SHIFTING THE LOW LEVEL JET
EAST.

A RECENT AIRCRAFT DESCENT SOUNDING INTO GRAND RAPIDS FROM THE
KALAMAZOO VICINITY SHOWED A NEARLY ISOTHERMAL LAYER JUST BELOW
FREEZING THAT EXTENDING UP TO ABOUT 6000 FT. THE WARM NOSE AT THE
TOP OF THIS LAYER...ASSOCIATED WITH THE LLJ...IS WEAK /AROUND 1
C/. ALL ELSE BEING EQUAL...THIS WOULD SUPPORT MOSTLY SNOW WITH SOME
FZRA. DO NOT EXPECT THE WARM LAYER TO REINTENSIFY AS THE LLJ PEELS
OFF TO THE EAST AND UNDERGOES DIURNAL WEAKENING THIS MORNING. FZRA
NEAR I-96 THIS MORNING SHOULD BE BECOME RAIN BY THIS AFTERNOON...
ALTHOUGH THERE COULD BE A DELAY IN SURFACE TEMPERATURES CLIMBING
ABOVE FREEZING AFTER AIR TEMPERATURES DO.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

WILL MAINTAIN THE HEADLINE AS IS.  THE WINTRY MIX WILL CONTINUE...
ALTHOUGH IT WILL TREND TOWARD MORE SNOW FROM NW TO SE THROUGH THE
MORNING.

COMPLICATED FORECAST DAY AS WE WILL SEE EBBS AND FLOWS IN THE PCPN
TODAY.  AS OF 08Z WE WERE SEEING AN AREA OF MIXED PCPN MOVING INTO
THE REGION.  THIS WAS ON THE NOSE OF THE LOW LEVEL JET.  IT WAS A
FAIRLY NARROW BAND THAT WAS MOVING NE AT 30 KNOTS.  SO THIS WON/T BE
OVER ANY ONE AREA FOR MUCH MORE THAN A COUPLE HOURS...BUT ENOUGH TO
PUT DOWN A LIGHT GLAZE AND IMPACT THE MORNING COMMUTE.

IT APPEARS WE WILL THAN HAVE A SHORT BREAK IN THE PCPN AROUND MID
MORNING...THEN THE DEFORMATION ZONE MOVES IN LATE MORNING/EARLY
AFTERNOON.  THIS SHOULD BE MOSTLY SNOW...WITH PERHAPS SOME MIX STILL
ALONG I-94.  FINALLY...ONCE THE DEEPER MOISTURE EXITS WE MAY SEE A
PERIOD OF FREEZING DRIZZLE AS THE DGZ BECOMES UNSATURATED.  THE
NORTHERN CWA APPEARS SETUP BEST FOR THIS AS SOME OMEGA IS STILL SEEN
WITHIN THE CLOUD LAYER.  THE FZDZ COULD LAST THROUGH THE LATTER HALF
OF THE AFTERNOON...BEFORE IT COMES AN END.  ALL-IN-ALL A MESSY DAY.
HOWEVER ANY ICE ACCUMULATION SHOULD REMAIN UNDER A TENTH OF AN
INCH.  SNOW ACCUMULATIONS SHOULD BE LESS THAN AN INCH ALONG I-96...
AND UP TO TWO INCHES TOWARD HIGHWAY 10.

WE WILL GET INTO A PERIOD OF LIGHT LAKE EFFECT SNOWS TONIGHT AND
FRIDAY AS -15C H8 AIR MOVES OVER THE LAKE.  THE MEAN LOW LEVEL FLOW
WILL BE 318-330 WHICH WILL FAVOR AREAS WEST OF U.S. 131.  INVERSION
LEVELS REMAIN LOW...4500 FT OR LESS...SO NOT EXPECTING ANYTHING
HEAVY.  AN INCH OR TWO CAN BE EXPECTED HERE...WHILE INLAND AREAS SEE
LESS THAN AN INCH.  IT WILL TURN SHARPLY COLDER WITH LOWS OF 10 TO
15 TONIGHT AND FRIDAY NIGHT...WHILE FRIDAY/S HIGHS WILL ONLY BE
AROUND 20.

A COLD FRONT WILL SLOWLY DROP IN FROM THE NW BY LATE SATURDAY.  THE
FRONT LOOKS FAIRLY MOISTURE STARVED...BUT COMBINED WITH SOME LAKE
ENHANCEMENT WE MAY BE ABLE TO SQUEEZE OUT UP TO AN INCH OF SNOW OVER
THE NW CWA AS IT COMES IN.  SW WINDS AHEAD OF THE FRONT WILL HELP
TEMPS APPROACH 30.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

LITTLE CHANGE TO THE PREVIOUS FORECAST EXCEPT TO LOWER POPS/QPF
FURTHER ON SUNDAY. CONFIDENCE IS GROWING THAT BEST PROSPECTS FOR
MEASURABLE SNOW LOOK TO BE SOUTH OF I-96...IF NOT SOUTH OF I-94.

NEXT NOTABLE CHANCE FOR SNOW IS TUESDAY WITH A BURST OF WARM
ADVECTION THAT IS PORTRAYED MORE AGGRESSIVELY BY THE GFS THAN THE
ECMWF. THIS WILL BE FOLLOWED BY A SIGNIFICANT INTRUSION OF COLD AIR
WEDNESDAY AND THURSDAY...WITH THE 29/00Z ECMWF DOWN TO -25C AT 850
MB BY THURSDAY MORNING. THIS WILL BE FAVORABLE FOR LAKE EFFECT
SNOW...BUT AMOUNTS SHOULD BE GREATLY CURTAILED BY UNFAVORABLE
MICROPHYSICS ASSOCIATED WITH THE VERY COLD AIR. ADVERTISED HIGHS
THURSDAY ARE CURRENTLY IN THE TEENS...BUT THIS MAY NEED TO BE
LOWERED IF THE ECWMF TRENDS CONTINUE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 120 PM EST THU JAN 29 2015

IFR CONDITIONS SHOULD IMPROVE TO MVFR AS LIGHT SNOW WILL BE ENDING
BY LATE AFTERNOON EXCEPT NEAR LAKE MICHIGAN WHERE SOME SNOW SHOWERS
WILL BE POSSIBLE INTO THIS EVENING. THEN EXPECT MVFR CONDITIONS TO
PREVAIL OVERNIGHT AS A STRATUS DECK WITH BASES AROUND 2500 FEET
AGL PERSISTS INTO FRIDAY MORNING. NORTHEAST WINDS WILL GUST OVER
20 KNOTS AT TIMES.

&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ037-
     043-044-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...TJT
AVIATION...OSTUNO
HYDROLOGY...JAM







000
FXUS63 KGRR 291821
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
121 PM EST THU JAN 29 2015

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 318 AM EST THU JAN 29 2015

A WINTRY MIX WILL CONTINUE TODAY.  SOME AREAS MAY SEE UP TO A TENTH
OF INCH OF ICE BY MID DAY.  THE PRECIPITATION WILL BE CHANGING OVER
TO MOSTLY SNOW BY THIS AFTERNOON.  AND AS COLDER AIR MOVES IN...SOME
LAKE EFFECT SNOW WILL DEVELOP TONIGHT AND CONTINUE INTO FRIDAY.
HOWEVER SNOW ACCUMULATIONS ARE EXPECTED TO BE LIGHT...GENERALLY AN
INCH OR TWO.  AFTER HIGHS IN THE 30S TODAY...IT WILL COOL TO ONLY
AROUND 20 BY FRIDAY.

A STORM SYSTEM WILL MOVE SOUTH OF THE AREA SUNDAY AND MONDAY.  WE
WILL HAVE TO KEEP AN EYE ON THIS AS IT MAY GIVE SOUTHWEST MICHIGAN
MORE SNOW.  EITHER WAY...IT WILL GET MUCH COLDER INTO NEXT WEEK WITH
DAYTIME HIGHS ONLY IN THE TEENS SUNDAY THROUGH WEDNESDAY.

&&

.UPDATE...
ISSUED AT 949 AM EST THU JAN 29 2015

UPDATED THE FORECAST TO INCLUDE SOME FREEZING RAIN EVEN FOR
NORTHEAST COUNTIES. REED CITY CAME IN WITH FREEZING RAIN RECENTLY
AS THE DGZ BECAME UNSATURATED. OVERALL PRIMARILY SNOW IS EXPECTED
FOR THE NORTHEAST COUNTIES INCLUDING BIG RAPIDS AND HARRISON.

UPDATE ISSUED AT 759 AM EST THU JAN 29 2015

WE ARE IN THE EXPECTED LULL BETWEEN FREEZING RAIN THAT EXITED EAST
AND AN UPSTREAM BATCH OF PRECIPITATION CROSSING WISCONSIN AND
NORTHERN LOWER MI. THIS UPSTREAM PRECIPITATION IS ASSOCIATED WITH
AN UPPER DEFORMATION ZONE AND EXPECTED TO REMAIN ALL SNOW OVER
CENTRAL AND NORTHERN LOWER MI. FARTHER SOUTH THE FORECAST WILL BE
MORE COMPLEX. THE SURFACE LOW CURRENTLY NEAR CHICAGO IS EXPECTED
TO MOVE EAST ACROSS NRN IN/OH TODAY...SHIFTING THE LOW LEVEL JET
EAST.

A RECENT AIRCRAFT DESCENT SOUNDING INTO GRAND RAPIDS FROM THE
KALAMAZOO VICINITY SHOWED A NEARLY ISOTHERMAL LAYER JUST BELOW
FREEZING THAT EXTENDING UP TO ABOUT 6000 FT. THE WARM NOSE AT THE
TOP OF THIS LAYER...ASSOCIATED WITH THE LLJ...IS WEAK /AROUND 1
C/. ALL ELSE BEING EQUAL...THIS WOULD SUPPORT MOSTLY SNOW WITH SOME
FZRA. DO NOT EXPECT THE WARM LAYER TO REINTENSIFY AS THE LLJ PEELS
OFF TO THE EAST AND UNDERGOES DIURNAL WEAKENING THIS MORNING. FZRA
NEAR I-96 THIS MORNING SHOULD BE BECOME RAIN BY THIS AFTERNOON...
ALTHOUGH THERE COULD BE A DELAY IN SURFACE TEMPERATURES CLIMBING
ABOVE FREEZING AFTER AIR TEMPERATURES DO.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

WILL MAINTAIN THE HEADLINE AS IS.  THE WINTRY MIX WILL CONTINUE...
ALTHOUGH IT WILL TREND TOWARD MORE SNOW FROM NW TO SE THROUGH THE
MORNING.

COMPLICATED FORECAST DAY AS WE WILL SEE EBBS AND FLOWS IN THE PCPN
TODAY.  AS OF 08Z WE WERE SEEING AN AREA OF MIXED PCPN MOVING INTO
THE REGION.  THIS WAS ON THE NOSE OF THE LOW LEVEL JET.  IT WAS A
FAIRLY NARROW BAND THAT WAS MOVING NE AT 30 KNOTS.  SO THIS WON/T BE
OVER ANY ONE AREA FOR MUCH MORE THAN A COUPLE HOURS...BUT ENOUGH TO
PUT DOWN A LIGHT GLAZE AND IMPACT THE MORNING COMMUTE.

IT APPEARS WE WILL THAN HAVE A SHORT BREAK IN THE PCPN AROUND MID
MORNING...THEN THE DEFORMATION ZONE MOVES IN LATE MORNING/EARLY
AFTERNOON.  THIS SHOULD BE MOSTLY SNOW...WITH PERHAPS SOME MIX STILL
ALONG I-94.  FINALLY...ONCE THE DEEPER MOISTURE EXITS WE MAY SEE A
PERIOD OF FREEZING DRIZZLE AS THE DGZ BECOMES UNSATURATED.  THE
NORTHERN CWA APPEARS SETUP BEST FOR THIS AS SOME OMEGA IS STILL SEEN
WITHIN THE CLOUD LAYER.  THE FZDZ COULD LAST THROUGH THE LATTER HALF
OF THE AFTERNOON...BEFORE IT COMES AN END.  ALL-IN-ALL A MESSY DAY.
HOWEVER ANY ICE ACCUMULATION SHOULD REMAIN UNDER A TENTH OF AN
INCH.  SNOW ACCUMULATIONS SHOULD BE LESS THAN AN INCH ALONG I-96...
AND UP TO TWO INCHES TOWARD HIGHWAY 10.

WE WILL GET INTO A PERIOD OF LIGHT LAKE EFFECT SNOWS TONIGHT AND
FRIDAY AS -15C H8 AIR MOVES OVER THE LAKE.  THE MEAN LOW LEVEL FLOW
WILL BE 318-330 WHICH WILL FAVOR AREAS WEST OF U.S. 131.  INVERSION
LEVELS REMAIN LOW...4500 FT OR LESS...SO NOT EXPECTING ANYTHING
HEAVY.  AN INCH OR TWO CAN BE EXPECTED HERE...WHILE INLAND AREAS SEE
LESS THAN AN INCH.  IT WILL TURN SHARPLY COLDER WITH LOWS OF 10 TO
15 TONIGHT AND FRIDAY NIGHT...WHILE FRIDAY/S HIGHS WILL ONLY BE
AROUND 20.

A COLD FRONT WILL SLOWLY DROP IN FROM THE NW BY LATE SATURDAY.  THE
FRONT LOOKS FAIRLY MOISTURE STARVED...BUT COMBINED WITH SOME LAKE
ENHANCEMENT WE MAY BE ABLE TO SQUEEZE OUT UP TO AN INCH OF SNOW OVER
THE NW CWA AS IT COMES IN.  SW WINDS AHEAD OF THE FRONT WILL HELP
TEMPS APPROACH 30.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

LITTLE CHANGE TO THE PREVIOUS FORECAST EXCEPT TO LOWER POPS/QPF
FURTHER ON SUNDAY. CONFIDENCE IS GROWING THAT BEST PROSPECTS FOR
MEASURABLE SNOW LOOK TO BE SOUTH OF I-96...IF NOT SOUTH OF I-94.

NEXT NOTABLE CHANCE FOR SNOW IS TUESDAY WITH A BURST OF WARM
ADVECTION THAT IS PORTRAYED MORE AGGRESSIVELY BY THE GFS THAN THE
ECMWF. THIS WILL BE FOLLOWED BY A SIGNIFICANT INTRUSION OF COLD AIR
WEDNESDAY AND THURSDAY...WITH THE 29/00Z ECMWF DOWN TO -25C AT 850
MB BY THURSDAY MORNING. THIS WILL BE FAVORABLE FOR LAKE EFFECT
SNOW...BUT AMOUNTS SHOULD BE GREATLY CURTAILED BY UNFAVORABLE
MICROPHYSICS ASSOCIATED WITH THE VERY COLD AIR. ADVERTISED HIGHS
THURSDAY ARE CURRENTLY IN THE TEENS...BUT THIS MAY NEED TO BE
LOWERED IF THE ECWMF TRENDS CONTINUE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 120 PM EST THU JAN 29 2015

IFR CONDITIONS SHOULD IMPROVE TO MVFR AS LIGHT SNOW WILL BE ENDING
BY LATE AFTERNOON EXCEPT NEAR LAKE MICHIGAN WHERE SOME SNOW SHOWERS
WILL BE POSSIBLE INTO THIS EVENING. THEN EXPECT MVFR CONDITIONS TO
PREVAIL OVERNIGHT AS A STRATUS DECK WITH BASES AROUND 2500 FEET
AGL PERSISTS INTO FRIDAY MORNING. NORTHEAST WINDS WILL GUST OVER
20 KNOTS AT TIMES.

&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ037-
     043-044-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...TJT
AVIATION...OSTUNO
HYDROLOGY...JAM








000
FXUS63 KGRR 291607
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1107 AM EST THU JAN 29 2015

LATEST UPDATE...
HYDRO

.SYNOPSIS...
ISSUED AT 318 AM EST THU JAN 29 2015

A WINTRY MIX WILL CONTINUE TODAY.  SOME AREAS MAY SEE UP TO A TENTH
OF INCH OF ICE BY MID DAY.  THE PRECIPITATION WILL BE CHANGING OVER
TO MOSTLY SNOW BY THIS AFTERNOON.  AND AS COLDER AIR MOVES IN...SOME
LAKE EFFECT SNOW WILL DEVELOP TONIGHT AND CONTINUE INTO FRIDAY.
HOWEVER SNOW ACCUMULATIONS ARE EXPECTED TO BE LIGHT...GENERALLY AN
INCH OR TWO.  AFTER HIGHS IN THE 30S TODAY...IT WILL COOL TO ONLY
AROUND 20 BY FRIDAY.

A STORM SYSTEM WILL MOVE SOUTH OF THE AREA SUNDAY AND MONDAY.  WE
WILL HAVE TO KEEP AN EYE ON THIS AS IT MAY GIVE SOUTHWEST MICHIGAN
MORE SNOW.  EITHER WAY...IT WILL GET MUCH COLDER INTO NEXT WEEK WITH
DAYTIME HIGHS ONLY IN THE TEENS SUNDAY THROUGH WEDNESDAY.

&&

.UPDATE...
ISSUED AT 949 AM EST THU JAN 29 2015

UPDATED THE FORECAST TO INCLUDE SOME FREEZING RAIN EVEN FOR
NORTHEAST COUNTIES. REED CITY CAME IN WITH FREEZING RAIN RECENTLY
AS THE DGZ BECAME UNSATURATED. OVERALL PRIMARILY SNOW IS EXPECTED
FOR THE NORTHEAST COUNTIES INCLUDING BIG RAPIDS AND HARRISON.

UPDATE ISSUED AT 759 AM EST THU JAN 29 2015

WE ARE IN THE EXPECTED LULL BETWEEN FREEZING RAIN THAT EXITED EAST
AND AN UPSTREAM BATCH OF PRECIPITATION CROSSING WISCONSIN AND
NORTHERN LOWER MI. THIS UPSTREAM PRECIPITATION IS ASSOCIATED WITH
AN UPPER DEFORMATION ZONE AND EXPECTED TO REMAIN ALL SNOW OVER
CENTRAL AND NORTHERN LOWER MI. FARTHER SOUTH THE FORECAST WILL BE
MORE COMPLEX. THE SURFACE LOW CURRENTLY NEAR CHICAGO IS EXPECTED
TO MOVE EAST ACROSS NRN IN/OH TODAY...SHIFTING THE LOW LEVEL JET
EAST.

A RECENT AIRCRAFT DESCENT SOUNDING INTO GRAND RAPIDS FROM THE
KALAMAZOO VICINITY SHOWED A NEARLY ISOTHERMAL LAYER JUST BELOW
FREEZING THAT EXTENDING UP TO ABOUT 6000 FT. THE WARM NOSE AT THE
TOP OF THIS LAYER...ASSOCIATED WITH THE LLJ...IS WEAK /AROUND 1
C/. ALL ELSE BEING EQUAL...THIS WOULD SUPPORT MOSTLY SNOW WITH SOME
FZRA. DO NOT EXPECT THE WARM LAYER TO REINTENSIFY AS THE LLJ PEELS
OFF TO THE EAST AND UNDERGOES DIURNAL WEAKENING THIS MORNING. FZRA
NEAR I-96 THIS MORNING SHOULD BE BECOME RAIN BY THIS AFTERNOON...
ALTHOUGH THERE COULD BE A DELAY IN SURFACE TEMPERATURES CLIMBING
ABOVE FREEZING AFTER AIR TEMPERATURES DO.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

WILL MAINTAIN THE HEADLINE AS IS.  THE WINTRY MIX WILL CONTINUE...
ALTHOUGH IT WILL TREND TOWARD MORE SNOW FROM NW TO SE THROUGH THE
MORNING.

COMPLICATED FORECAST DAY AS WE WILL SEE EBBS AND FLOWS IN THE PCPN
TODAY.  AS OF 08Z WE WERE SEEING AN AREA OF MIXED PCPN MOVING INTO
THE REGION.  THIS WAS ON THE NOSE OF THE LOW LEVEL JET.  IT WAS A
FAIRLY NARROW BAND THAT WAS MOVING NE AT 30 KNOTS.  SO THIS WON/T BE
OVER ANY ONE AREA FOR MUCH MORE THAN A COUPLE HOURS...BUT ENOUGH TO
PUT DOWN A LIGHT GLAZE AND IMPACT THE MORNING COMMUTE.

IT APPEARS WE WILL THAN HAVE A SHORT BREAK IN THE PCPN AROUND MID
MORNING...THEN THE DEFORMATION ZONE MOVES IN LATE MORNING/EARLY
AFTERNOON.  THIS SHOULD BE MOSTLY SNOW...WITH PERHAPS SOME MIX STILL
ALONG I-94.  FINALLY...ONCE THE DEEPER MOISTURE EXITS WE MAY SEE A
PERIOD OF FREEZING DRIZZLE AS THE DGZ BECOMES UNSATURATED.  THE
NORTHERN CWA APPEARS SETUP BEST FOR THIS AS SOME OMEGA IS STILL SEEN
WITHIN THE CLOUD LAYER.  THE FZDZ COULD LAST THROUGH THE LATTER HALF
OF THE AFTERNOON...BEFORE IT COMES AN END.  ALL-IN-ALL A MESSY DAY.
HOWEVER ANY ICE ACCUMULATION SHOULD REMAIN UNDER A TENTH OF AN
INCH.  SNOW ACCUMULATIONS SHOULD BE LESS THAN AN INCH ALONG I-96...
AND UP TO TWO INCHES TOWARD HIGHWAY 10.

WE WILL GET INTO A PERIOD OF LIGHT LAKE EFFECT SNOWS TONIGHT AND
FRIDAY AS -15C H8 AIR MOVES OVER THE LAKE.  THE MEAN LOW LEVEL FLOW
WILL BE 318-330 WHICH WILL FAVOR AREAS WEST OF U.S. 131.  INVERSION
LEVELS REMAIN LOW...4500 FT OR LESS...SO NOT EXPECTING ANYTHING
HEAVY.  AN INCH OR TWO CAN BE EXPECTED HERE...WHILE INLAND AREAS SEE
LESS THAN AN INCH.  IT WILL TURN SHARPLY COLDER WITH LOWS OF 10 TO
15 TONIGHT AND FRIDAY NIGHT...WHILE FRIDAY/S HIGHS WILL ONLY BE
AROUND 20.

A COLD FRONT WILL SLOWLY DROP IN FROM THE NW BY LATE SATURDAY.  THE
FRONT LOOKS FAIRLY MOISTURE STARVED...BUT COMBINED WITH SOME LAKE
ENHANCEMENT WE MAY BE ABLE TO SQUEEZE OUT UP TO AN INCH OF SNOW OVER
THE NW CWA AS IT COMES IN.  SW WINDS AHEAD OF THE FRONT WILL HELP
TEMPS APPROACH 30.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

LITTLE CHANGE TO THE PREVIOUS FORECAST EXCEPT TO LOWER POPS/QPF
FURTHER ON SUNDAY. CONFIDENCE IS GROWING THAT BEST PROSPECTS FOR
MEASURABLE SNOW LOOK TO BE SOUTH OF I-96...IF NOT SOUTH OF I-94.

NEXT NOTABLE CHANCE FOR SNOW IS TUESDAY WITH A BURST OF WARM
ADVECTION THAT IS PORTRAYED MORE AGGRESSIVELY BY THE GFS THAN THE
ECMWF. THIS WILL BE FOLLOWED BY A SIGNIFICANT INTRUSION OF COLD AIR
WEDNESDAY AND THURSDAY...WITH THE 29/00Z ECMWF DOWN TO -25C AT 850
MB BY THURSDAY MORNING. THIS WILL BE FAVORABLE FOR LAKE EFFECT
SNOW...BUT AMOUNTS SHOULD BE GREATLY CURTAILED BY UNFAVORABLE
MICROPHYSICS ASSOCIATED WITH THE VERY COLD AIR. ADVERTISED HIGHS
THURSDAY ARE CURRENTLY IN THE TEENS...BUT THIS MAY NEED TO BE
LOWERED IF THE ECWMF TRENDS CONTINUE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 720 AM EST THU JAN 29 2015

RADAR INDICATES THAT THE AREA OF FREEZING RAIN HAS MOVED INTO EASTERN
LOWER MI. THE FORECAST CHALLENGE NOW TURNS TO ASSESSING THE TIMING
AND CHARACTER OF THE NEXT BATCH OF PRECIPITATION. THIS WILL BE DEPENDENT
ON THE SURFACE LOW PRESSURE SYSTEM CURRENTLY CENTERED NEAR
CHICAGO. AS THIS LOW MOVES EAST ACROSS NORTHERN IN/OH TODAY...THERE
WILL BE A SHIFT TO NORTHWEST WINDS...GRADUAL COOLING...AND AN
EVENTUAL TRANSITION TO ALL SNOW.

NEXT AREA OF PRECIPITATION CURRENTLY SEEN UPSTREAM OVER WI IS
EXPECTED TO ENTER THE AREA IN THE 14-16Z TIMEFRAME. LATEST
GUIDANCE SUGGESTS THAT THERE WILL BE AN INITIAL RAIN/SNOW
MIX...HOWEVER SPOTTY PL IS ALSO POSSIBLE. SURFACE TEMPERATURES
AROUND THE GRR AND LAN TERMINALS COULD REMAIN BELOW FREEZING THE
REST OF THE MORNING...CONTINUING THE FZRA THREAT.

IT IS UNCERTAIN HOW QUICKLY THE TRANSITION TO SNOW WILL OCCUR.
EARLIER FORECASTS AND GUIDANCE SUGGESTED A MUCH MORE ABRUPT
TRANSITION...WHEREAS THIS UPDATE FEATURES A TRANSITION PERIOD OF
RAIN/SNOW DUE TO WARMER AIR BEING BROUGHT INTO THE AREA BY THE
LOW. THE MOST LIKELY ALTERNATE OUTCOME WOULD BE A CLEAN TRANSITION
FROM RA/FZRA TO SNOW SOMETIME THIS AFTERNOON.


&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ037-
     043-044-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...JAM







000
FXUS63 KGRR 291607
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1107 AM EST THU JAN 29 2015

LATEST UPDATE...
HYDRO

.SYNOPSIS...
ISSUED AT 318 AM EST THU JAN 29 2015

A WINTRY MIX WILL CONTINUE TODAY.  SOME AREAS MAY SEE UP TO A TENTH
OF INCH OF ICE BY MID DAY.  THE PRECIPITATION WILL BE CHANGING OVER
TO MOSTLY SNOW BY THIS AFTERNOON.  AND AS COLDER AIR MOVES IN...SOME
LAKE EFFECT SNOW WILL DEVELOP TONIGHT AND CONTINUE INTO FRIDAY.
HOWEVER SNOW ACCUMULATIONS ARE EXPECTED TO BE LIGHT...GENERALLY AN
INCH OR TWO.  AFTER HIGHS IN THE 30S TODAY...IT WILL COOL TO ONLY
AROUND 20 BY FRIDAY.

A STORM SYSTEM WILL MOVE SOUTH OF THE AREA SUNDAY AND MONDAY.  WE
WILL HAVE TO KEEP AN EYE ON THIS AS IT MAY GIVE SOUTHWEST MICHIGAN
MORE SNOW.  EITHER WAY...IT WILL GET MUCH COLDER INTO NEXT WEEK WITH
DAYTIME HIGHS ONLY IN THE TEENS SUNDAY THROUGH WEDNESDAY.

&&

.UPDATE...
ISSUED AT 949 AM EST THU JAN 29 2015

UPDATED THE FORECAST TO INCLUDE SOME FREEZING RAIN EVEN FOR
NORTHEAST COUNTIES. REED CITY CAME IN WITH FREEZING RAIN RECENTLY
AS THE DGZ BECAME UNSATURATED. OVERALL PRIMARILY SNOW IS EXPECTED
FOR THE NORTHEAST COUNTIES INCLUDING BIG RAPIDS AND HARRISON.

UPDATE ISSUED AT 759 AM EST THU JAN 29 2015

WE ARE IN THE EXPECTED LULL BETWEEN FREEZING RAIN THAT EXITED EAST
AND AN UPSTREAM BATCH OF PRECIPITATION CROSSING WISCONSIN AND
NORTHERN LOWER MI. THIS UPSTREAM PRECIPITATION IS ASSOCIATED WITH
AN UPPER DEFORMATION ZONE AND EXPECTED TO REMAIN ALL SNOW OVER
CENTRAL AND NORTHERN LOWER MI. FARTHER SOUTH THE FORECAST WILL BE
MORE COMPLEX. THE SURFACE LOW CURRENTLY NEAR CHICAGO IS EXPECTED
TO MOVE EAST ACROSS NRN IN/OH TODAY...SHIFTING THE LOW LEVEL JET
EAST.

A RECENT AIRCRAFT DESCENT SOUNDING INTO GRAND RAPIDS FROM THE
KALAMAZOO VICINITY SHOWED A NEARLY ISOTHERMAL LAYER JUST BELOW
FREEZING THAT EXTENDING UP TO ABOUT 6000 FT. THE WARM NOSE AT THE
TOP OF THIS LAYER...ASSOCIATED WITH THE LLJ...IS WEAK /AROUND 1
C/. ALL ELSE BEING EQUAL...THIS WOULD SUPPORT MOSTLY SNOW WITH SOME
FZRA. DO NOT EXPECT THE WARM LAYER TO REINTENSIFY AS THE LLJ PEELS
OFF TO THE EAST AND UNDERGOES DIURNAL WEAKENING THIS MORNING. FZRA
NEAR I-96 THIS MORNING SHOULD BE BECOME RAIN BY THIS AFTERNOON...
ALTHOUGH THERE COULD BE A DELAY IN SURFACE TEMPERATURES CLIMBING
ABOVE FREEZING AFTER AIR TEMPERATURES DO.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

WILL MAINTAIN THE HEADLINE AS IS.  THE WINTRY MIX WILL CONTINUE...
ALTHOUGH IT WILL TREND TOWARD MORE SNOW FROM NW TO SE THROUGH THE
MORNING.

COMPLICATED FORECAST DAY AS WE WILL SEE EBBS AND FLOWS IN THE PCPN
TODAY.  AS OF 08Z WE WERE SEEING AN AREA OF MIXED PCPN MOVING INTO
THE REGION.  THIS WAS ON THE NOSE OF THE LOW LEVEL JET.  IT WAS A
FAIRLY NARROW BAND THAT WAS MOVING NE AT 30 KNOTS.  SO THIS WON/T BE
OVER ANY ONE AREA FOR MUCH MORE THAN A COUPLE HOURS...BUT ENOUGH TO
PUT DOWN A LIGHT GLAZE AND IMPACT THE MORNING COMMUTE.

IT APPEARS WE WILL THAN HAVE A SHORT BREAK IN THE PCPN AROUND MID
MORNING...THEN THE DEFORMATION ZONE MOVES IN LATE MORNING/EARLY
AFTERNOON.  THIS SHOULD BE MOSTLY SNOW...WITH PERHAPS SOME MIX STILL
ALONG I-94.  FINALLY...ONCE THE DEEPER MOISTURE EXITS WE MAY SEE A
PERIOD OF FREEZING DRIZZLE AS THE DGZ BECOMES UNSATURATED.  THE
NORTHERN CWA APPEARS SETUP BEST FOR THIS AS SOME OMEGA IS STILL SEEN
WITHIN THE CLOUD LAYER.  THE FZDZ COULD LAST THROUGH THE LATTER HALF
OF THE AFTERNOON...BEFORE IT COMES AN END.  ALL-IN-ALL A MESSY DAY.
HOWEVER ANY ICE ACCUMULATION SHOULD REMAIN UNDER A TENTH OF AN
INCH.  SNOW ACCUMULATIONS SHOULD BE LESS THAN AN INCH ALONG I-96...
AND UP TO TWO INCHES TOWARD HIGHWAY 10.

WE WILL GET INTO A PERIOD OF LIGHT LAKE EFFECT SNOWS TONIGHT AND
FRIDAY AS -15C H8 AIR MOVES OVER THE LAKE.  THE MEAN LOW LEVEL FLOW
WILL BE 318-330 WHICH WILL FAVOR AREAS WEST OF U.S. 131.  INVERSION
LEVELS REMAIN LOW...4500 FT OR LESS...SO NOT EXPECTING ANYTHING
HEAVY.  AN INCH OR TWO CAN BE EXPECTED HERE...WHILE INLAND AREAS SEE
LESS THAN AN INCH.  IT WILL TURN SHARPLY COLDER WITH LOWS OF 10 TO
15 TONIGHT AND FRIDAY NIGHT...WHILE FRIDAY/S HIGHS WILL ONLY BE
AROUND 20.

A COLD FRONT WILL SLOWLY DROP IN FROM THE NW BY LATE SATURDAY.  THE
FRONT LOOKS FAIRLY MOISTURE STARVED...BUT COMBINED WITH SOME LAKE
ENHANCEMENT WE MAY BE ABLE TO SQUEEZE OUT UP TO AN INCH OF SNOW OVER
THE NW CWA AS IT COMES IN.  SW WINDS AHEAD OF THE FRONT WILL HELP
TEMPS APPROACH 30.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

LITTLE CHANGE TO THE PREVIOUS FORECAST EXCEPT TO LOWER POPS/QPF
FURTHER ON SUNDAY. CONFIDENCE IS GROWING THAT BEST PROSPECTS FOR
MEASURABLE SNOW LOOK TO BE SOUTH OF I-96...IF NOT SOUTH OF I-94.

NEXT NOTABLE CHANCE FOR SNOW IS TUESDAY WITH A BURST OF WARM
ADVECTION THAT IS PORTRAYED MORE AGGRESSIVELY BY THE GFS THAN THE
ECMWF. THIS WILL BE FOLLOWED BY A SIGNIFICANT INTRUSION OF COLD AIR
WEDNESDAY AND THURSDAY...WITH THE 29/00Z ECMWF DOWN TO -25C AT 850
MB BY THURSDAY MORNING. THIS WILL BE FAVORABLE FOR LAKE EFFECT
SNOW...BUT AMOUNTS SHOULD BE GREATLY CURTAILED BY UNFAVORABLE
MICROPHYSICS ASSOCIATED WITH THE VERY COLD AIR. ADVERTISED HIGHS
THURSDAY ARE CURRENTLY IN THE TEENS...BUT THIS MAY NEED TO BE
LOWERED IF THE ECWMF TRENDS CONTINUE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 720 AM EST THU JAN 29 2015

RADAR INDICATES THAT THE AREA OF FREEZING RAIN HAS MOVED INTO EASTERN
LOWER MI. THE FORECAST CHALLENGE NOW TURNS TO ASSESSING THE TIMING
AND CHARACTER OF THE NEXT BATCH OF PRECIPITATION. THIS WILL BE DEPENDENT
ON THE SURFACE LOW PRESSURE SYSTEM CURRENTLY CENTERED NEAR
CHICAGO. AS THIS LOW MOVES EAST ACROSS NORTHERN IN/OH TODAY...THERE
WILL BE A SHIFT TO NORTHWEST WINDS...GRADUAL COOLING...AND AN
EVENTUAL TRANSITION TO ALL SNOW.

NEXT AREA OF PRECIPITATION CURRENTLY SEEN UPSTREAM OVER WI IS
EXPECTED TO ENTER THE AREA IN THE 14-16Z TIMEFRAME. LATEST
GUIDANCE SUGGESTS THAT THERE WILL BE AN INITIAL RAIN/SNOW
MIX...HOWEVER SPOTTY PL IS ALSO POSSIBLE. SURFACE TEMPERATURES
AROUND THE GRR AND LAN TERMINALS COULD REMAIN BELOW FREEZING THE
REST OF THE MORNING...CONTINUING THE FZRA THREAT.

IT IS UNCERTAIN HOW QUICKLY THE TRANSITION TO SNOW WILL OCCUR.
EARLIER FORECASTS AND GUIDANCE SUGGESTED A MUCH MORE ABRUPT
TRANSITION...WHEREAS THIS UPDATE FEATURES A TRANSITION PERIOD OF
RAIN/SNOW DUE TO WARMER AIR BEING BROUGHT INTO THE AREA BY THE
LOW. THE MOST LIKELY ALTERNATE OUTCOME WOULD BE A CLEAN TRANSITION
FROM RA/FZRA TO SNOW SOMETIME THIS AFTERNOON.


&&

.HYDROLOGY...
ISSUED AT 1107 AM EST THU JAN 29 2015

LITTLE PRECIPITATION FELL OVERNIGHT INTO THIS MORNING. ONLY MINOR
ADDITIONAL PRECIPITATION IS ANTICIPATED THROUGH THE REMAINDER OF
THE WEEK. MAXIMUM TEMPERATURES WILL VARY FROM DAY TO DAY THROUGH
THE WEEKEND BEFORE MUCH COLDER AIR MOVES IN EARLY NEXT WEEK.
OVERALL TEMPERATURES WILL BE NEAR OR BELOW NORMAL TO SUPPORT ICE
BUILD UP ON RIVERS. RIVERS SHOULD REMAIN STABLE INTO NEXT WEEK.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ037-
     043-044-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...JAM








000
FXUS63 KGRR 291451
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
951 AM EST THU JAN 29 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 318 AM EST THU JAN 29 2015

A WINTRY MIX WILL CONTINUE TODAY.  SOME AREAS MAY SEE UP TO A TENTH
OF INCH OF ICE BY MID DAY.  THE PRECIPITATION WILL BE CHANGING OVER
TO MOSTLY SNOW BY THIS AFTERNOON.  AND AS COLDER AIR MOVES IN...SOME
LAKE EFFECT SNOW WILL DEVELOP TONIGHT AND CONTINUE INTO FRIDAY.
HOWEVER SNOW ACCUMULATIONS ARE EXPECTED TO BE LIGHT...GENERALLY AN
INCH OR TWO.  AFTER HIGHS IN THE 30S TODAY...IT WILL COOL TO ONLY
AROUND 20 BY FRIDAY.

A STORM SYSTEM WILL MOVE SOUTH OF THE AREA SUNDAY AND MONDAY.  WE
WILL HAVE TO KEEP AN EYE ON THIS AS IT MAY GIVE SOUTHWEST MICHIGAN
MORE SNOW.  EITHER WAY...IT WILL GET MUCH COLDER INTO NEXT WEEK WITH
DAYTIME HIGHS ONLY IN THE TEENS SUNDAY THROUGH WEDNESDAY.

&&

.UPDATE...
ISSUED AT 949 AM EST THU JAN 29 2015

UPDATED THE FORECAST TO INCLUDE SOME FREEZING RAIN EVEN FOR
NORTHEAST COUNTIES. REED CITY CAME IN WITH FREEZING RAIN RECENTLY
AS THE DGZ BECAME UNSATURATED. OVERALL PRIMARILY SNOW IS EXPECTED
FOR THE NORTHEAST COUNTIES INCLUDING BIG RAPIDS AND HARRISON.

UPDATE ISSUED AT 759 AM EST THU JAN 29 2015

WE ARE IN THE EXPECTED LULL BETWEEN FREEZING RAIN THAT EXITED EAST
AND AN UPSTREAM BATCH OF PRECIPITATION CROSSING WISCONSIN AND
NORTHERN LOWER MI. THIS UPSTREAM PRECIPITATION IS ASSOCIATED WITH
AN UPPER DEFORMATION ZONE AND EXPECTED TO REMAIN ALL SNOW OVER
CENTRAL AND NORTHERN LOWER MI. FARTHER SOUTH THE FORECAST WILL BE
MORE COMPLEX. THE SURFACE LOW CURRENTLY NEAR CHICAGO IS EXPECTED
TO MOVE EAST ACROSS NRN IN/OH TODAY...SHIFTING THE LOW LEVEL JET
EAST.

A RECENT AIRCRAFT DESCENT SOUNDING INTO GRAND RAPIDS FROM THE
KALAMAZOO VICINITY SHOWED A NEARLY ISOTHERMAL LAYER JUST BELOW
FREEZING THAT EXTENDING UP TO ABOUT 6000 FT. THE WARM NOSE AT THE
TOP OF THIS LAYER...ASSOCIATED WITH THE LLJ...IS WEAK /AROUND 1
C/. ALL ELSE BEING EQUAL...THIS WOULD SUPPORT MOSTLY SNOW WITH SOME
FZRA. DO NOT EXPECT THE WARM LAYER TO REINTENSIFY AS THE LLJ PEELS
OFF TO THE EAST AND UNDERGOES DIURNAL WEAKENING THIS MORNING. FZRA
NEAR I-96 THIS MORNING SHOULD BE BECOME RAIN BY THIS AFTERNOON...
ALTHOUGH THERE COULD BE A DELAY IN SURFACE TEMPERATURES CLIMBING
ABOVE FREEZING AFTER AIR TEMPERATURES DO.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

WILL MAINTAIN THE HEADLINE AS IS.  THE WINTRY MIX WILL CONTINUE...
ALTHOUGH IT WILL TREND TOWARD MORE SNOW FROM NW TO SE THROUGH THE
MORNING.

COMPLICATED FORECAST DAY AS WE WILL SEE EBBS AND FLOWS IN THE PCPN
TODAY.  AS OF 08Z WE WERE SEEING AN AREA OF MIXED PCPN MOVING INTO
THE REGION.  THIS WAS ON THE NOSE OF THE LOW LEVEL JET.  IT WAS A
FAIRLY NARROW BAND THAT WAS MOVING NE AT 30 KNOTS.  SO THIS WON/T BE
OVER ANY ONE AREA FOR MUCH MORE THAN A COUPLE HOURS...BUT ENOUGH TO
PUT DOWN A LIGHT GLAZE AND IMPACT THE MORNING COMMUTE.

IT APPEARS WE WILL THAN HAVE A SHORT BREAK IN THE PCPN AROUND MID
MORNING...THEN THE DEFORMATION ZONE MOVES IN LATE MORNING/EARLY
AFTERNOON.  THIS SHOULD BE MOSTLY SNOW...WITH PERHAPS SOME MIX STILL
ALONG I-94.  FINALLY...ONCE THE DEEPER MOISTURE EXITS WE MAY SEE A
PERIOD OF FREEZING DRIZZLE AS THE DGZ BECOMES UNSATURATED.  THE
NORTHERN CWA APPEARS SETUP BEST FOR THIS AS SOME OMEGA IS STILL SEEN
WITHIN THE CLOUD LAYER.  THE FZDZ COULD LAST THROUGH THE LATTER HALF
OF THE AFTERNOON...BEFORE IT COMES AN END.  ALL-IN-ALL A MESSY DAY.
HOWEVER ANY ICE ACCUMULATION SHOULD REMAIN UNDER A TENTH OF AN
INCH.  SNOW ACCUMULATIONS SHOULD BE LESS THAN AN INCH ALONG I-96...
AND UP TO TWO INCHES TOWARD HIGHWAY 10.

WE WILL GET INTO A PERIOD OF LIGHT LAKE EFFECT SNOWS TONIGHT AND
FRIDAY AS -15C H8 AIR MOVES OVER THE LAKE.  THE MEAN LOW LEVEL FLOW
WILL BE 318-330 WHICH WILL FAVOR AREAS WEST OF U.S. 131.  INVERSION
LEVELS REMAIN LOW...4500 FT OR LESS...SO NOT EXPECTING ANYTHING
HEAVY.  AN INCH OR TWO CAN BE EXPECTED HERE...WHILE INLAND AREAS SEE
LESS THAN AN INCH.  IT WILL TURN SHARPLY COLDER WITH LOWS OF 10 TO
15 TONIGHT AND FRIDAY NIGHT...WHILE FRIDAY/S HIGHS WILL ONLY BE
AROUND 20.

A COLD FRONT WILL SLOWLY DROP IN FROM THE NW BY LATE SATURDAY.  THE
FRONT LOOKS FAIRLY MOISTURE STARVED...BUT COMBINED WITH SOME LAKE
ENHANCEMENT WE MAY BE ABLE TO SQUEEZE OUT UP TO AN INCH OF SNOW OVER
THE NW CWA AS IT COMES IN.  SW WINDS AHEAD OF THE FRONT WILL HELP
TEMPS APPROACH 30.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

LITTLE CHANGE TO THE PREVIOUS FORECAST EXCEPT TO LOWER POPS/QPF
FURTHER ON SUNDAY. CONFIDENCE IS GROWING THAT BEST PROSPECTS FOR
MEASURABLE SNOW LOOK TO BE SOUTH OF I-96...IF NOT SOUTH OF I-94.

NEXT NOTABLE CHANCE FOR SNOW IS TUESDAY WITH A BURST OF WARM
ADVECTION THAT IS PORTRAYED MORE AGGRESSIVELY BY THE GFS THAN THE
ECMWF. THIS WILL BE FOLLOWED BY A SIGNIFICANT INTRUSION OF COLD AIR
WEDNESDAY AND THURSDAY...WITH THE 29/00Z ECMWF DOWN TO -25C AT 850
MB BY THURSDAY MORNING. THIS WILL BE FAVORABLE FOR LAKE EFFECT
SNOW...BUT AMOUNTS SHOULD BE GREATLY CURTAILED BY UNFAVORABLE
MICROPHYSICS ASSOCIATED WITH THE VERY COLD AIR. ADVERTISED HIGHS
THURSDAY ARE CURRENTLY IN THE TEENS...BUT THIS MAY NEED TO BE
LOWERED IF THE ECWMF TRENDS CONTINUE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 720 AM EST THU JAN 29 2015

RADAR INDICATES THAT THE AREA OF FREEZING RAIN HAS MOVED INTO EASTERN
LOWER MI. THE FORECAST CHALLENGE NOW TURNS TO ASSESSING THE TIMING
AND CHARACTER OF THE NEXT BATCH OF PRECIPITATION. THIS WILL BE DEPENDENT
ON THE SURFACE LOW PRESSURE SYSTEM CURRENTLY CENTERED NEAR
CHICAGO. AS THIS LOW MOVES EAST ACROSS NORTHERN IN/OH TODAY...THERE
WILL BE A SHIFT TO NORTHWEST WINDS...GRADUAL COOLING...AND AN
EVENTUAL TRANSITION TO ALL SNOW.

NEXT AREA OF PRECIPITATION CURRENTLY SEEN UPSTREAM OVER WI IS
EXPECTED TO ENTER THE AREA IN THE 14-16Z TIMEFRAME. LATEST
GUIDANCE SUGGESTS THAT THERE WILL BE AN INITIAL RAIN/SNOW
MIX...HOWEVER SPOTTY PL IS ALSO POSSIBLE. SURFACE TEMPERATURES
AROUND THE GRR AND LAN TERMINALS COULD REMAIN BELOW FREEZING THE
REST OF THE MORNING...CONTINUING THE FZRA THREAT.

IT IS UNCERTAIN HOW QUICKLY THE TRANSITION TO SNOW WILL OCCUR.
EARLIER FORECASTS AND GUIDANCE SUGGESTED A MUCH MORE ABRUPT
TRANSITION...WHEREAS THIS UPDATE FEATURES A TRANSITION PERIOD OF
RAIN/SNOW DUE TO WARMER AIR BEING BROUGHT INTO THE AREA BY THE
LOW. THE MOST LIKELY ALTERNATE OUTCOME WOULD BE A CLEAN TRANSITION
FROM RA/FZRA TO SNOW SOMETIME THIS AFTERNOON.


&&

.HYDROLOGY...
ISSUED AT 328 PM EST WED JAN 28 2015

COLD WEATHER WITH ONLY LIGHT PRECIPITATION SHOULD MEAN NO
SIGNIFICANT TRENDS IN THE RIVERS. ICE WILL FORM OVER THE WEEKEND
AS THE COLD INTENSIFIES.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ037-
     043-044-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...OSTUNO








000
FXUS63 KGRR 291451
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
951 AM EST THU JAN 29 2015

LATEST UPDATE...
UPDATE

.SYNOPSIS...
ISSUED AT 318 AM EST THU JAN 29 2015

A WINTRY MIX WILL CONTINUE TODAY.  SOME AREAS MAY SEE UP TO A TENTH
OF INCH OF ICE BY MID DAY.  THE PRECIPITATION WILL BE CHANGING OVER
TO MOSTLY SNOW BY THIS AFTERNOON.  AND AS COLDER AIR MOVES IN...SOME
LAKE EFFECT SNOW WILL DEVELOP TONIGHT AND CONTINUE INTO FRIDAY.
HOWEVER SNOW ACCUMULATIONS ARE EXPECTED TO BE LIGHT...GENERALLY AN
INCH OR TWO.  AFTER HIGHS IN THE 30S TODAY...IT WILL COOL TO ONLY
AROUND 20 BY FRIDAY.

A STORM SYSTEM WILL MOVE SOUTH OF THE AREA SUNDAY AND MONDAY.  WE
WILL HAVE TO KEEP AN EYE ON THIS AS IT MAY GIVE SOUTHWEST MICHIGAN
MORE SNOW.  EITHER WAY...IT WILL GET MUCH COLDER INTO NEXT WEEK WITH
DAYTIME HIGHS ONLY IN THE TEENS SUNDAY THROUGH WEDNESDAY.

&&

.UPDATE...
ISSUED AT 949 AM EST THU JAN 29 2015

UPDATED THE FORECAST TO INCLUDE SOME FREEZING RAIN EVEN FOR
NORTHEAST COUNTIES. REED CITY CAME IN WITH FREEZING RAIN RECENTLY
AS THE DGZ BECAME UNSATURATED. OVERALL PRIMARILY SNOW IS EXPECTED
FOR THE NORTHEAST COUNTIES INCLUDING BIG RAPIDS AND HARRISON.

UPDATE ISSUED AT 759 AM EST THU JAN 29 2015

WE ARE IN THE EXPECTED LULL BETWEEN FREEZING RAIN THAT EXITED EAST
AND AN UPSTREAM BATCH OF PRECIPITATION CROSSING WISCONSIN AND
NORTHERN LOWER MI. THIS UPSTREAM PRECIPITATION IS ASSOCIATED WITH
AN UPPER DEFORMATION ZONE AND EXPECTED TO REMAIN ALL SNOW OVER
CENTRAL AND NORTHERN LOWER MI. FARTHER SOUTH THE FORECAST WILL BE
MORE COMPLEX. THE SURFACE LOW CURRENTLY NEAR CHICAGO IS EXPECTED
TO MOVE EAST ACROSS NRN IN/OH TODAY...SHIFTING THE LOW LEVEL JET
EAST.

A RECENT AIRCRAFT DESCENT SOUNDING INTO GRAND RAPIDS FROM THE
KALAMAZOO VICINITY SHOWED A NEARLY ISOTHERMAL LAYER JUST BELOW
FREEZING THAT EXTENDING UP TO ABOUT 6000 FT. THE WARM NOSE AT THE
TOP OF THIS LAYER...ASSOCIATED WITH THE LLJ...IS WEAK /AROUND 1
C/. ALL ELSE BEING EQUAL...THIS WOULD SUPPORT MOSTLY SNOW WITH SOME
FZRA. DO NOT EXPECT THE WARM LAYER TO REINTENSIFY AS THE LLJ PEELS
OFF TO THE EAST AND UNDERGOES DIURNAL WEAKENING THIS MORNING. FZRA
NEAR I-96 THIS MORNING SHOULD BE BECOME RAIN BY THIS AFTERNOON...
ALTHOUGH THERE COULD BE A DELAY IN SURFACE TEMPERATURES CLIMBING
ABOVE FREEZING AFTER AIR TEMPERATURES DO.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

WILL MAINTAIN THE HEADLINE AS IS.  THE WINTRY MIX WILL CONTINUE...
ALTHOUGH IT WILL TREND TOWARD MORE SNOW FROM NW TO SE THROUGH THE
MORNING.

COMPLICATED FORECAST DAY AS WE WILL SEE EBBS AND FLOWS IN THE PCPN
TODAY.  AS OF 08Z WE WERE SEEING AN AREA OF MIXED PCPN MOVING INTO
THE REGION.  THIS WAS ON THE NOSE OF THE LOW LEVEL JET.  IT WAS A
FAIRLY NARROW BAND THAT WAS MOVING NE AT 30 KNOTS.  SO THIS WON/T BE
OVER ANY ONE AREA FOR MUCH MORE THAN A COUPLE HOURS...BUT ENOUGH TO
PUT DOWN A LIGHT GLAZE AND IMPACT THE MORNING COMMUTE.

IT APPEARS WE WILL THAN HAVE A SHORT BREAK IN THE PCPN AROUND MID
MORNING...THEN THE DEFORMATION ZONE MOVES IN LATE MORNING/EARLY
AFTERNOON.  THIS SHOULD BE MOSTLY SNOW...WITH PERHAPS SOME MIX STILL
ALONG I-94.  FINALLY...ONCE THE DEEPER MOISTURE EXITS WE MAY SEE A
PERIOD OF FREEZING DRIZZLE AS THE DGZ BECOMES UNSATURATED.  THE
NORTHERN CWA APPEARS SETUP BEST FOR THIS AS SOME OMEGA IS STILL SEEN
WITHIN THE CLOUD LAYER.  THE FZDZ COULD LAST THROUGH THE LATTER HALF
OF THE AFTERNOON...BEFORE IT COMES AN END.  ALL-IN-ALL A MESSY DAY.
HOWEVER ANY ICE ACCUMULATION SHOULD REMAIN UNDER A TENTH OF AN
INCH.  SNOW ACCUMULATIONS SHOULD BE LESS THAN AN INCH ALONG I-96...
AND UP TO TWO INCHES TOWARD HIGHWAY 10.

WE WILL GET INTO A PERIOD OF LIGHT LAKE EFFECT SNOWS TONIGHT AND
FRIDAY AS -15C H8 AIR MOVES OVER THE LAKE.  THE MEAN LOW LEVEL FLOW
WILL BE 318-330 WHICH WILL FAVOR AREAS WEST OF U.S. 131.  INVERSION
LEVELS REMAIN LOW...4500 FT OR LESS...SO NOT EXPECTING ANYTHING
HEAVY.  AN INCH OR TWO CAN BE EXPECTED HERE...WHILE INLAND AREAS SEE
LESS THAN AN INCH.  IT WILL TURN SHARPLY COLDER WITH LOWS OF 10 TO
15 TONIGHT AND FRIDAY NIGHT...WHILE FRIDAY/S HIGHS WILL ONLY BE
AROUND 20.

A COLD FRONT WILL SLOWLY DROP IN FROM THE NW BY LATE SATURDAY.  THE
FRONT LOOKS FAIRLY MOISTURE STARVED...BUT COMBINED WITH SOME LAKE
ENHANCEMENT WE MAY BE ABLE TO SQUEEZE OUT UP TO AN INCH OF SNOW OVER
THE NW CWA AS IT COMES IN.  SW WINDS AHEAD OF THE FRONT WILL HELP
TEMPS APPROACH 30.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 318 AM EST THU JAN 29 2015

LITTLE CHANGE TO THE PREVIOUS FORECAST EXCEPT TO LOWER POPS/QPF
FURTHER ON SUNDAY. CONFIDENCE IS GROWING THAT BEST PROSPECTS FOR
MEASURABLE SNOW LOOK TO BE SOUTH OF I-96...IF NOT SOUTH OF I-94.

NEXT NOTABLE CHANCE FOR SNOW IS TUESDAY WITH A BURST OF WARM
ADVECTION THAT IS PORTRAYED MORE AGGRESSIVELY BY THE GFS THAN THE
ECMWF. THIS WILL BE FOLLOWED BY A SIGNIFICANT INTRUSION OF COLD AIR
WEDNESDAY AND THURSDAY...WITH THE 29/00Z ECMWF DOWN TO -25C AT 850
MB BY THURSDAY MORNING. THIS WILL BE FAVORABLE FOR LAKE EFFECT
SNOW...BUT AMOUNTS SHOULD BE GREATLY CURTAILED BY UNFAVORABLE
MICROPHYSICS ASSOCIATED WITH THE VERY COLD AIR. ADVERTISED HIGHS
THURSDAY ARE CURRENTLY IN THE TEENS...BUT THIS MAY NEED TO BE
LOWERED IF THE ECWMF TRENDS CONTINUE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 720 AM EST THU JAN 29 2015

RADAR INDICATES THAT THE AREA OF FREEZING RAIN HAS MOVED INTO EASTERN
LOWER MI. THE FORECAST CHALLENGE NOW TURNS TO ASSESSING THE TIMING
AND CHARACTER OF THE NEXT BATCH OF PRECIPITATION. THIS WILL BE DEPENDENT
ON THE SURFACE LOW PRESSURE SYSTEM CURRENTLY CENTERED NEAR
CHICAGO. AS THIS LOW MOVES EAST ACROSS NORTHERN IN/OH TODAY...THERE
WILL BE A SHIFT TO NORTHWEST WINDS...GRADUAL COOLING...AND AN
EVENTUAL TRANSITION TO ALL SNOW.

NEXT AREA OF PRECIPITATION CURRENTLY SEEN UPSTREAM OVER WI IS
EXPECTED TO ENTER THE AREA IN THE 14-16Z TIMEFRAME. LATEST
GUIDANCE SUGGESTS THAT THERE WILL BE AN INITIAL RAIN/SNOW
MIX...HOWEVER SPOTTY PL IS ALSO POSSIBLE. SURFACE TEMPERATURES
AROUND THE GRR AND LAN TERMINALS COULD REMAIN BELOW FREEZING THE
REST OF THE MORNING...CONTINUING THE FZRA THREAT.

IT IS UNCERTAIN HOW QUICKLY THE TRANSITION TO SNOW WILL OCCUR.
EARLIER FORECASTS AND GUIDANCE SUGGESTED A MUCH MORE ABRUPT
TRANSITION...WHEREAS THIS UPDATE FEATURES A TRANSITION PERIOD OF
RAIN/SNOW DUE TO WARMER AIR BEING BROUGHT INTO THE AREA BY THE
LOW. THE MOST LIKELY ALTERNATE OUTCOME WOULD BE A CLEAN TRANSITION
FROM RA/FZRA TO SNOW SOMETIME THIS AFTERNOON.


&&

.HYDROLOGY...
ISSUED AT 328 PM EST WED JAN 28 2015

COLD WEATHER WITH ONLY LIGHT PRECIPITATION SHOULD MEAN NO
SIGNIFICANT TRENDS IN THE RIVERS. ICE WILL FORM OVER THE WEEKEND
AS THE COLD INTENSIFIES.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ037-
     043-044-050>052-056>059-064>067-071>074.

LM...NONE.
&&

$$

UPDATE...MJS
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...TJT
AVIATION...TJT
HYDROLOGY...OSTUNO







    US Dept of Commerce
    National Oceanic and Atmospheric Administration
    National Weather Service
    1325 East West Highway
    Silver Spring, MD 20910
    Page Author: NWS Internet Services Team
Disclaimer
Information Quality
Credits
Glossary
Privacy Policy
Freedom of Information Act (FOIA)
About Us
Career Opportunities