000
FXUS62 KRAH 250119
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
920 PM EDT FRI MAY 24 2013
.SYNOPSIS...
A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE CAROLINAS THROUGH
TONIGHT...THEN LINGER OVERHEAD THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /TONIGHT/...
AS OF 920 PM FRIDAY...
...NEAR-RECORD LOWS TONIGHT...
SUBSIDENCE IN THE WAKE OF THE SHORTWAVE TROUGH PUSHING OFF TO THE
EAST COMBINED WITH CONTINUED LOW-LEVEL DRY COOL AIR ADVECTION
WILL RESULT IN CHILLY CONDITIONS. WIND GUSTS HAVE ALREADY SUBSIDED
AT THE MAJORITY OF THE OBSERVATIONS SITES WITH A LIGHT NORTHWESTERLY
BREEZE EXPECTED FOR THE REMAINDER OF THE NIGHT. STILL EXPECT
NEAR-RECORD LOWS RANGING FROM THE LOWER TO MIDDLE 40S WITH SOME
UPPER 30S POSSIBLE IN SHELTERED LOCATIONS (SEE CLIMATE SECTION BELOW
FOR RECORDS).
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 315 PM FRIDAY...
HIGH PRESSURE WILL BE CENTERED OVER THE SE STATES ON SATURDAY.
HOWEVER WITH THE MID LEVEL RIDGE STILL OVER THE PLAINS...NW FLOW
ALOFT WILL CONTINUE...AND WILL BRING SOME MID AND HIGH CLOUDS ACROSS
OUR AREA STARTING TOMORROW AFTERNOON. NEVERTHELESS...SATURDAY SHOULD
BE A PLEASANT DAY WITH PLENTY OF SUNSHINE AND HIGHS IN THE LOW TO
MID 70S.
LATEST GUIDANCE SUGGESTS THE MID/HIGH CLOUDS WILL CONTINUE OVER OUR
AREA SATURDAY NIGHT...THUS LOOK FOR SLIGHTLY WARMER OVERNIGHT LOWS
BUT STILL COOLER THAN NORMAL...UPPER 40S ACROSS MOST OF CENTRAL NC.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 250 PM FRIDAY...
SUNDAY INTO MONDAY...
A DEEP UPPER LEVEL LOW OVER THE NORTHERN MID ATLANTIC-SOUTHERN NEW
ENGLAND COAST EARLY SUNDAY WILL CONTINUE TO MOVE NWD THROUGH EARLY
MONDAY AND BE POSITIONED OVER THE CANADIAN MARITIMES. DUE TO THE
BROAD CIRCULATION ASSOCIATED WITH THIS SYSTEM IN COMBINATION WITH A
BUILDING MID-UPPER LEVEL RIDGE IN THE CENTRAL U.S....A NW FLOW WILL
EXIST ALOFT OVER CENTRAL NC THROUGH THIS PERIOD. WHILE THIS FLOW
WILL MAINTAIN COOL AND DRY CONDITIONS...CONVECTIVE CLOUD DEBRIS FROM
ANY CONVECTION THAT DEVELOPS OVER THE UPPER MIDWEST WILL SPREAD
SEWD INTO OUR PART OF THE COUNTRY SUNDAY INTO MONDAY. PER LATEST
MODEL HUMIDITY CROSS SECTIONS...THESE CLOUDS MAY BE MORE PROMINENT
ACROSS OUR WEST AND SOUTH SECTIONS VERSUS THE NE.
LOW LEVEL THICKNESSES AVERAGE 10-20M BELOW NORMAL THROUGH THE
PERIOD...SUGGESTIVE OF MAX TEMPS 3-6 DEGREES BELOW NORMAL FOR LATE
MAY. EXPECT MAX TEMPS SUNDAY MID=UPPER 70S...AND 75-80 MONDAY. MIN
TEMPS SUNDAY NIGHT SHOULD BE MORE MILD COMPARED TO PREVIOUS NIGHTS
DUE TO AN UPTICK IN CLOUD COVERAGE AND A MODIFYING AIR MASS. MIN
TEMPS SUNDAY NIGHT LOW-MID 50S.
MONDAY NIGHT THROUGH TUESDAY NIGHT...
THE PATTERN OF AN UPPER LEVEL RIDGE OVER THE MS VALLEY AND AN UPPER
LEVEL LOW OVER THE CANADIAN MARITIMES WILL MAINTAIN THE NW FLOW
ALOFT OVER THE CAROLINAS. MODEL GUIDANCE CONTINUES TO SUGGEST THE
POTENTIAL FOR A CONVECTIVELY INDUCE VORTICITY MAXIMUM TO
APPROACH/CROSS OUR REGION MONDAY NIGHT THROUGH TUESDAY. TIMING STILL
UNCERTAIN AS THIS FEATURE HAS YET TO DEVELOP SO WILL NEED TO MONITOR
CONDITIONS TO OUR NW (MINNESOTA/WISCONSIN) SUNDAY INTO MONDAY FOR
CONVECTIVE DEVELOPMENT. THIS FEATURE IN TANDEM WITH AN INCREASINGLY
MOIST AIR MASS OVER THE CAROLINAS MAY SUPPORT THE
DEVELOPMENT/SUSTAIN ISOLATED-SCATTERED CONVECTION MONDAY NIGHT INTO
TUESDAY. BASED ON EXPECTED MID-UPPER FLOW...OUR NORTHERN COUNTIES
WILL STAND A BETTER CHANCE OF SEEING ANY CONVECTION VERSUS THE
SOUTHERN COUNTIES. FOR NOW WILL CONTINUE TO MENTION SLIGHT CHANCE
POP AND SEE HOW THE SCENARIO EVOLVES MONDAY. EXPECT WARMER TEMPS
TUESDAY AS LOW LEVEL FLOW BECOME MORE SW....SENDING THICKNESSES BACK
TO NEAR OR ABOVE NORMAL VALUES. MAX TEMPS 80-85. MIN TEMPS MONDAY
NIGHT UPPER 50S TO LOWER 60S...AND LOW-MID 60S TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY...
MODEL GUIDANCE CONTINUE TO ADVERTISE AN AMPLIFYING MID-UPPER LEVEL
RIDGE OVER THE DEEP SOUTH-GREAT LAKES...DRIFTING EAST INTO THE
SOUTHEAST U.S. THE WARMING ALOFT ASSOCIATED WITH THE RISING HEIGHTS
WILL INDUCE THE FORMATION OF A MID LEVEL INVERSION...WHICH WILL ACT
AS A CAP OR LID ON THE ATMOSPHERE. THIS SHOULD LIMIT CONVECTIVE
DEVELOPMENT. WILL LIMIT SLIGHT CHANCE POPS TO WEDNESDAY WITH POPS
LESS THAN 20 PERCENT THU-FRI. THE WARMING AIR MASS WILL SEND LOW
LEVEL THICKNESSES INTO THE 1415-1420M RANGE...ABOUT 15M ABOVE
NORMAL. POSITION AND STRENGTH OF THE MID-UPPER LEVEL ANTI-CYCLONE
OVER THE SE U.S. SUGGEST MAX TEMPS WELL ABOVE NORMAL....WITH TEMPS
AROUND 90 PROBABLE THU-FRI. WILL ADVERTISE TEMPS IN THE MID-UPPER
80S FOR NOW SINCE WE ARE TALKING DAYS 7/8.
&&
.AVIATION /00Z SATURDAY THROUGH TUESDAY/...
AS OF 745 PM FRIDAY...
SUBSIDENCE IN THE WAKE OF DEPARTING SHORTWAVE TROUGH AND LOW-LEVEL
COOL DRY AIR ADVECTION WILL RESULT IN VFR CONDITIONS TO CONTINUE
THROUGH THE 24 HOUR TAF PERIOD. BREEZY NWLY WINDS WILL DECOUPLE
SHORTLY AFTER SUNSET.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH ARE EXPECTED TO BE NEAR RECORD
MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
FAY 46 / 1967 44 / 1988
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...CBL/NP
SHORT TERM...NP
LONG TERM...WSS
AVIATION...CBL/NP
CLIMATE...RAH
000
FXUS62 KRAH 242344
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
745 PM EDT FRI MAY 24 2013
.SYNOPSIS...
A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE CAROLINAS THROUGH
TONIGHT...THEN LINGER OVERHEAD THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /TONIGHT/...
AS OF 315 PM FRIDAY...
SHORT WAVE CROSSING THE REGION ATTM WILL MOVE EAST THIS EVENING.
SUBSIDENCE AND DRYING ALREADY UNDERWAY ACROSS OUR AREA AND WILL
RESULT IN SKIES CONTINUING TO CLEAR OVER THE NEXT FEW HOURS. AT THE
SFC...HIGH PRESSURE OVER THE OH VALLEY WILL BUILD SOUTH AND EAST...
THUS WITH DECREASING PRES GRADIENT...LOOK FOR WINDS TO SUBSIDE
OVERNIGHT. THE COMBINATION OF CLEARING SKIES...DECREASING WIND...AND
COLDER AIRMASS WHICH HAS MOVED IN BEHIND THIS MORNINGS COLD
FRONT...TEMPS TONIGHT WILL FALL TO NEAR-RECORD LOWS...REACHING THE
LOWER TO MIDDLE 40S WITH SOME UPPER 30S POSSIBLE IN SHELTERED
LOCATIONS (SEE CLIMATE SECTION BELOW FOR RECORDS).
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 315 PM FRIDAY...
HIGH PRESSURE WILL BE CENTERED OVER THE SE STATES ON SATURDAY.
HOWEVER WITH THE MID LEVEL RIDGE STILL OVER THE PLAINS...NW FLOW
ALOFT WILL CONTINUE...AND WILL BRING SOME MID AND HIGH CLOUDS ACROSS
OUR AREA STARTING TOMORROW AFTERNOON. NEVERTHELESS...SATURDAY SHOULD
BE A PLEASANT DAY WITH PLENTY OF SUNSHINE AND HIGHS IN THE LOW TO
MID 70S.
LATEST GUIDANCE SUGGESTS THE MID/HIGH CLOUDS WILL CONTINUE OVER OUR
AREA SATURDAY NIGHT...THUS LOOK FOR SLIGHTLY WARMER OVERNIGHT LOWS
BUT STILL COOLER THAN NORMAL...UPPER 40S ACROSS MOST OF CENTRAL NC.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 250 PM FRIDAY...
SUNDAY INTO MONDAY...
A DEEP UPPER LEVEL LOW OVER THE NORTHERN MID ATLANTIC-SOUTHERN NEW
ENGLAND COAST EARLY SUNDAY WILL CONTINUE TO MOVE NWD THROUGH EARLY
MONDAY AND BE POSITIONED OVER THE CANADIAN MARITIMES. DUE TO THE
BROAD CIRCULATION ASSOCIATED WITH THIS SYSTEM IN COMBINATION WITH A
BUILDING MID-UPPER LEVEL RIDGE IN THE CENTRAL U.S....A NW FLOW WILL
EXIST ALOFT OVER CENTRAL NC THROUGH THIS PERIOD. WHILE THIS FLOW
WILL MAINTAIN COOL AND DRY CONDITIONS...CONVECTIVE CLOUD DEBRIS FROM
ANY CONVECTION THAT DEVELOPS OVER THE UPPER MIDWEST WILL SPREAD
SEWD INTO OUR PART OF THE COUNTRY SUNDAY INTO MONDAY. PER LATEST
MODEL HUMIDITY CROSS SECTIONS...THESE CLOUDS MAY BE MORE PROMINENT
ACROSS OUR WEST AND SOUTH SECTIONS VERSUS THE NE.
LOW LEVEL THICKNESSES AVERAGE 10-20M BELOW NORMAL THROUGH THE
PERIOD...SUGGESTIVE OF MAX TEMPS 3-6 DEGREES BELOW NORMAL FOR LATE
MAY. EXPECT MAX TEMPS SUNDAY MID=UPPER 70S...AND 75-80 MONDAY. MIN
TEMPS SUNDAY NIGHT SHOULD BE MORE MILD COMPARED TO PREVIOUS NIGHTS
DUE TO AN UPTICK IN CLOUD COVERAGE AND A MODIFYING AIR MASS. MIN
TEMPS SUNDAY NIGHT LOW-MID 50S.
MONDAY NIGHT THROUGH TUESDAY NIGHT...
THE PATTERN OF AN UPPER LEVEL RIDGE OVER THE MS VALLEY AND AN UPPER
LEVEL LOW OVER THE CANADIAN MARITIMES WILL MAINTAIN THE NW FLOW
ALOFT OVER THE CAROLINAS. MODEL GUIDANCE CONTINUES TO SUGGEST THE
POTENTIAL FOR A CONVECTIVELY INDUCE VORTICITY MAXIMUM TO
APPROACH/CROSS OUR REGION MONDAY NIGHT THROUGH TUESDAY. TIMING STILL
UNCERTAIN AS THIS FEATURE HAS YET TO DEVELOP SO WILL NEED TO MONITOR
CONDITIONS TO OUR NW (MINNESOTA/WISCONSIN) SUNDAY INTO MONDAY FOR
CONVECTIVE DEVELOPMENT. THIS FEATURE IN TANDEM WITH AN INCREASINGLY
MOIST AIR MASS OVER THE CAROLINAS MAY SUPPORT THE
DEVELOPMENT/SUSTAIN ISOLATED-SCATTERED CONVECTION MONDAY NIGHT INTO
TUESDAY. BASED ON EXPECTED MID-UPPER FLOW...OUR NORTHERN COUNTIES
WILL STAND A BETTER CHANCE OF SEEING ANY CONVECTION VERSUS THE
SOUTHERN COUNTIES. FOR NOW WILL CONTINUE TO MENTION SLIGHT CHANCE
POP AND SEE HOW THE SCENARIO EVOLVES MONDAY. EXPECT WARMER TEMPS
TUESDAY AS LOW LEVEL FLOW BECOME MORE SW....SENDING THICKNESSES BACK
TO NEAR OR ABOVE NORMAL VALUES. MAX TEMPS 80-85. MIN TEMPS MONDAY
NIGHT UPPER 50S TO LOWER 60S...AND LOW-MID 60S TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY...
MODEL GUIDANCE CONTINUE TO ADVERTISE AN AMPLIFYING MID-UPPER LEVEL
RIDGE OVER THE DEEP SOUTH-GREAT LAKES...DRIFTING EAST INTO THE
SOUTHEAST U.S. THE WARMING ALOFT ASSOCIATED WITH THE RISING HEIGHTS
WILL INDUCE THE FORMATION OF A MID LEVEL INVERSION...WHICH WILL ACT
AS A CAP OR LID ON THE ATMOSPHERE. THIS SHOULD LIMIT CONVECTIVE
DEVELOPMENT. WILL LIMIT SLIGHT CHANCE POPS TO WEDNESDAY WITH POPS
LESS THAN 20 PERCENT THU-FRI. THE WARMING AIR MASS WILL SEND LOW
LEVEL THICKNESSES INTO THE 1415-1420M RANGE...ABOUT 15M ABOVE
NORMAL. POSITION AND STRENGTH OF THE MID-UPPER LEVEL ANTI-CYCLONE
OVER THE SE U.S. SUGGEST MAX TEMPS WELL ABOVE NORMAL....WITH TEMPS
AROUND 90 PROBABLE THU-FRI. WILL ADVERTISE TEMPS IN THE MID-UPPER
80S FOR NOW SINCE WE ARE TALKING DAYS 7/8.
&&
.AVIATION /00Z SATURDAY THROUGH TUESDAY/...
AS OF 745 PM FRIDAY...
SUBSIDENCE IN THE WAKE OF DEPARTING SHORTWAVE TROUGH AND LOW-LEVEL
COOL DRY AIR ADVECTION WILL RESULT IN VFR CONDITIONS TO CONTINUE
THROUGH THE 24 HOUR TAF PERIOD. BREEZY NWLY WINDS WILL DECOUPLE
SHORTLY AFTER SUNSET.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH ARE EXPECTED TO BE NEAR RECORD
MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...NP
SHORT TERM...NP
LONG TERM...WSS
AVIATION...CBL/NP
CLIMATE...RAH
000
FXUS62 KRAH 241915
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
315 PM EDT FRI MAY 24 2013
.SYNOPSIS...
A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE CAROLINAS THROUGH
TONIGHT...THEN LINGER OVERHEAD THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /TONIGHT/...
AS OF 315 PM FRIDAY...
SHORT WAVE CROSSING THE REGION ATTM WILL MOVE EAST THIS EVENING.
SUBSIDENCE AND DRYING ALREADY UNDERWAY ACROSS OUR AREA AND WILL
RESULT IN SKIES CONTINUING TO CLEAR OVER THE NEXT FEW HOURS. AT THE
SFC...HIGH PRESSURE OVER THE OH VALLEY WILL BUILD SOUTH AND EAST...
THUS WITH DECREASING PRES GRADIENT...LOOK FOR WINDS TO SUBSIDE
OVERNIGHT. THE COMBINATION OF CLEARING SKIES...DECREASING WIND...AND
COLDER AIRMASS WHICH HAS MOVED IN BEHIND THIS MORNINGS COLD
FRONT...TEMPS TONIGHT WILL FALL TO NEAR-RECORD LOWS...REACHING THE
LOWER TO MIDDLE 40S WITH SOME UPPER 30S POSSIBLE IN SHELTERED
LOCATIONS (SEE CLIMATE SECTION BELOW FOR RECORDS).
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 315 PM FRIDAY...
HIGH PRESSURE WILL BE CENTERED OVER THE SE STATES ON SATURDAY.
HOWEVER WITH THE MID LEVEL RIDGE STILL OVER THE PLAINS...NW FLOW
ALOFT WILL CONTINUE...AND WILL BRING SOME MID AND HIGH CLOUDS ACROSS
OUR AREA STARTING TOMORROW AFTERNOON. NEVERTHELESS...SATURDAY SHOULD
BE A PLEASANT DAY WITH PLENTY OF SUNSHINE AND HIGHS IN THE LOW TO
MID 70S.
LATEST GUIDANCE SUGGESTS THE MID/HIGH CLOUDS WILL CONTINUE OVER OUR
AREA SATURDAY NIGHT...THUS LOOK FOR SLIGHTLY WARMER OVERNIGHT LOWS
BUT STILL COOLER THAN NORMAL...UPPER 40S ACROSS MOST OF CENTRAL NC.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 250 PM FRIDAY...
SUNDAY INTO MONDAY...
A DEEP UPPER LEVEL LOW OVER THE NORTHERN MID ATLANTIC-SOUTHERN NEW
ENGLAND COAST EARLY SUNDAY WILL CONTINUE TO MOVE NWD THROUGH EARLY
MONDAY AND BE POSITIONED OVER THE CANADIAN MARITIMES. DUE TO THE
BROAD CIRCULATION ASSOCIATED WITH THIS SYSTEM IN COMBINATION WITH A
BUILDING MID-UPPER LEVEL RIDGE IN THE CENTRAL U.S....A NW FLOW WILL
EXIST ALOFT OVER CENTRAL NC THROUGH THIS PERIOD. WHILE THIS FLOW
WILL MAINTAIN COOL AND DRY CONDITIONS...CONVECTIVE CLOUD DEBRIS FROM
ANY CONVECTION THAT DEVELOPS OVER THE UPPER MIDWEST WILL SPREAD
SEWD INTO OUR PART OF THE COUNTRY SUNDAY INTO MONDAY. PER LATEST
MODEL HUMIDITY CROSS SECTIONS...THESE CLOUDS MAY BE MORE PROMINENT
ACROSS OUR WEST AND SOUTH SECTIONS VERSUS THE NE.
LOW LEVEL THICKNESSES AVERAGE 10-20M BELOW NORMAL THROUGH THE
PERIOD...SUGGESTIVE OF MAX TEMPS 3-6 DEGREES BELOW NORMAL FOR LATE
MAY. EXPECT MAX TEMPS SUNDAY MID=UPPER 70S...AND 75-80 MONDAY. MIN
TEMPS SUNDAY NIGHT SHOULD BE MORE MILD COMPARED TO PREVIOUS NIGHTS
DUE TO AN UPTICK IN CLOUD COVERAGE AND A MODIFYING AIR MASS. MIN
TEMPS SUNDAY NIGHT LOW-MID 50S.
MONDAY NIGHT THROUGH TUESDAY NIGHT...
THE PATTERN OF AN UPPER LEVEL RIDGE OVER THE MS VALLEY AND AN UPPER
LEVEL LOW OVER THE CANADIAN MARITIMES WILL MAINTAIN THE NW FLOW
ALOFT OVER THE CAROLINAS. MODEL GUIDANCE CONTINUES TO SUGGEST THE
POTENTIAL FOR A CONVECTIVELY INDUCE VORTICITY MAXIMUM TO
APPROACH/CROSS OUR REGION MONDAY NIGHT THROUGH TUESDAY. TIMING STILL
UNCERTAIN AS THIS FEATURE HAS YET TO DEVELOP SO WILL NEED TO MONITOR
CONDITIONS TO OUR NW (MINNESOTA/WISCONSIN) SUNDAY INTO MONDAY FOR
CONVECTIVE DEVELOPMENT. THIS FEATURE IN TANDEM WITH AN INCREASINGLY
MOIST AIR MASS OVER THE CAROLINAS MAY SUPPORT THE
DEVELOPMENT/SUSTAIN ISOLATED-SCATTERED CONVECTION MONDAY NIGHT INTO
TUESDAY. BASED ON EXPECTED MID-UPPER FLOW...OUR NORTHERN COUNTIES
WILL STAND A BETTER CHANCE OF SEEING ANY CONVECTION VERSUS THE
SOUTHERN COUNTIES. FOR NOW WILL CONTINUE TO MENTION SLIGHT CHANCE
POP AND SEE HOW THE SCENARIO EVOLVES MONDAY. EXPECT WARMER TEMPS
TUESDAY AS LOW LEVEL FLOW BECOME MORE SW....SENDING THICKNESSES BACK
TO NEAR OR ABOVE NORMAL VALUES. MAX TEMPS 80-85. MIN TEMPS MONDAY
NIGHT UPPER 50S TO LOWER 60S...AND LOW-MID 60S TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY...
MODEL GUIDANCE CONTINUE TO ADVERTISE AN AMPLIFYING MID-UPPER LEVEL
RIDGE OVER THE DEEP SOUTH-GREAT LAKES...DRIFTING EAST INTO THE
SOUTHEAST U.S. THE WARMING ALOFT ASSOCIATED WITH THE RISING HEIGHTS
WILL INDUCE THE FORMATION OF A MID LEVEL INVERSION...WHICH WILL ACT
AS A CAP OR LID ON THE ATMOSPHERE. THIS SHOULD LIMIT CONVECTIVE
DEVELOPMENT. WILL LIMIT SLIGHT CHANCE POPS TO WEDNESDAY WITH POPS
LESS THAN 20 PERCENT THU-FRI. THE WARMING AIR MASS WILL SEND LOW
LEVEL THICKNESSES INTO THE 1415-1420M RANGE...ABOUT 15M ABOVE
NORMAL. POSITION AND STRENGTH OF THE MID-UPPER LEVEL ANTI-CYCLONE
OVER THE SE U.S. SUGGEST MAX TEMPS WELL ABOVE NORMAL....WITH TEMPS
AROUND 90 PROBABLE THU-FRI. WILL ADVERTISE TEMPS IN THE MID-UPPER
80S FOR NOW SINCE WE ARE TALKING DAYS 7/8.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 110 PM FRIDAY...
A BAND OF BKN CLOUDS WITH CIGS GREATER THAN 4K FT...ALONG WITH SOME
EMBEDDED SPRINKLES...IS QUICKLY MOVING EAST OF I-95. THIS IS
OCCURRING IN CONJUNCTION WITH A SECONDARY BOUNDARY MOVING ACROSS THE
AREA. DRIER AIR AS NOTED BY 20+ DEG DWPT DEPRESSIONS IS FOUND BEHIND
THIS BOUNDARY...ALONG WITH CLEARING SKIES. AS SUCH...LOOK FOR VFR
CONDITIONS TO CONTINUE THROUGH THE 24 HOUR TAF PERIOD. THE OTHER
MAIN CONCERN IS GUSTY NW WINDS. THROUGH SUNSET...LOOK FOR NW WINDS
10-15 KT WITH GUSTS IN THE LOW 20S. AFTER SUNSET AND THROUGH 18Z
SAT...LOOK FOR CLEAR SKIES AND LIGHT WINDS.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH ARE EXPECTED TO BE NEAR RECORD
MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...NP
SHORT TERM...NP
LONG TERM...WSS
AVIATION...NP/MWS
CLIMATE...RAH
000
FXUS62 KRAH 241848
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
250 PM EDT FRI MAY 24 2013
.SYNOPSIS...
A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE CAROLINAS THROUGH
TONIGHT...THEN LINGER OVERHEAD THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 1025 AM FRIDAY...
12Z ANALYSIS SHOWS THAT CURRENT FORECAST FOR TODAY IS ON TRACK PER
PREV DISCUSSION (INCLUDED BELOW FOR REFERENCE). THE ONLY ADJUSTMENT
WILL BE INCREASING THE NW WINDS A LITTLE SOONER. FORECAST SOUNDINGS
SHOW AVG BL WIND IN THE 24-28KT RANGE ACROSS MUCH OF CENTRAL NC
TODAY...AND THIS IS SUPPORTED BY TRENDS IN THE GSO OBSERVED
SOUNDING. WITH TEMPS ALREADY IN THE UPPER 60S TO AROUND 70...DEEP
MIXING IS UNDERWAY AND WE`RE ALREADY SEEING SFC GUSTS UP TO 25 KT
ACROSS OUR NW ZONES. OTHERWISE...LINGERING LIGHT SHOWERS ACROSS OUR
NE ZONES ARE ADDRESSED IN CURRENT POP/WX GRIDS...SO NO CHANGES
THERE. THIS ACTIVITY IS EXPECTED TO WIND DOWN AND MOVE EAST OF OUR
CWA BY EARLY TO MID AFTERNOON.
PREV DISCUSSION AS OF 230 AM FRIDAY...
AN UPPER LOW WILL AMPLIFY SOUTHEASTWARD FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC REGION TODAY. DESPITE STRONG HEIGHT FALLS AND
DYNAMIC FORCING FOR ASCENT CENTERED OVER VA AND NORTHERN NC IN
ASSOCIATION WITH THIS FEATURE...STRONG LOW LEVEL CAA WILL MOSTLY
OFFSET THIS FORCING...PER DEEP LAYER Q-VECTOR DIAGNOSTICS OVER
CENTRAL NC. AS SUCH...LINGERING MID LEVEL CLOUDINESS THIS MORNING
WILL YIELD TO INCREASINGLY SUBSIDENT AND CLEARING CONDITIONS
THROUGHOUT THE DAY...WITH JUST A SLIGHT CHANCE OF A SHOWER OVER THE
NORTHERN COASTAL THROUGH AROUND 18Z...IN CLOSEST PROXIMITY TO THE
AFOREMENTIONED STRONGEST HEIGHT FALLS ALOFT OVER VA. IT WILL ALSO
BECOME QUITE BREEZY LATE MORNING-MIDDAY ONWARD...AS COOLER AND MUCH
DRIER AIR ASSOCIATED WITH AN INCOMING CANADIAN SURFACE HIGH
OVERSPREADS OUR REGION. DRY ADIABATIC MIXING TO AROUND 6 THOUSAND FT
AND ADDED DOWNSLOPE WARMING SUGGESTS HIGHS IN THE LOWER 70S NW
PIEDMONT TO UPPER 70S SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 300 AM FRIDAY...
HEIGHT RISES IN DRY NORTHWESTERLY DEEP LAYER FLOW WILL DEVELOP
TONIGHT...THEN CONTINUE ON THE EASTERN PERIPHERY OF CANADIAN HIGH
PRESSURE THROUGH THE WEEKEND. PROJECTED LOW LEVEL
THICKNESSES...ACCOUNTING FOR CLEAR BUT CAA MIXING OVERNIGHT...
SUPPORT NEAR RECORD LOWS MOSTLY IN THE LOWER TO MIDDLE 40S...WITH
SOME UPPER 30S POSSIBLE IN SHELTERED (CALM) OUTLYING AREAS.
CLEAR/SUNNY CONDITIONS WILL PERSIST THROUGH SAT EVENING...BEFORE
YIELDING TO INCREASING MID-HIGH CLOUDS IN NW FLOW ALOFT OVERNIGHT.
HIGHS...WITH CONTINUED LOW HUMIDITY...IN THE LOWER TO MIDDLE 70S.
LOWS GENERAL 45 TO 50 DEGREES...WARMEST TRIAD WHERE MID-HIGH CLOUDS
WILL ARRIVE SOONEST (LATE SAT EVENING).
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 250 PM FRIDAY...
SUNDAY INTO MONDAY...
A DEEP UPPER LEVEL LOW OVER THE NORTHERN MID ATLANTIC-SOUTHERN NEW
ENGLAND COAST EARLY SUNDAY WILL CONTINUE TO MOVE NWD THROUGH EARLY
MONDAY AND BE POSITIONED OVER THE CANADIAN MARITIMES. DUE TO THE
BROAD CIRCULATION ASSOCIATED WITH THIS SYSTEM IN COMBINATION WITH A
BUILDING MID-UPPER LEVEL RIDGE IN THE CENTRAL U.S....A NW FLOW WILL
EXIST ALOFT OVER CENTRAL NC THROUGH THIS PERIOD. WHILE THIS FLOW
WILL MAINTAIN COOL AND DRY CONDITIONS...CONVECTIVE CLOUD DEBRIS FROM
ANY CONVECTION THAT DEVELOPS OVER THE UPPER MIDWEST WILL SPREAD
SEWD INTO OUR PART OF THE COUNTRY SUNDAY INTO MONDAY. PER LATEST
MODEL HUMIDITY CROSS SECTIONS...THESE CLOUDS MAY BE MORE PROMINENT
ACROSS OUR WEST AND SOUTH SECTIONS VERSUS THE NE.
LOW LEVEL THICKNESSES AVERAGE 10-20M BELOW NORMAL THROUGH THE
PERIOD...SUGGESTIVE OF MAX TEMPS 3-6 DEGREES BELOW NORMAL FOR LATE
MAY. EXPECT MAX TEMPS SUNDAY MID=UPPER 70S...AND 75-80 MONDAY. MIN
TEMPS SUNDAY NIGHT SHOULD BE MORE MILD COMPARED TO PREVIOUS NIGHTS
DUE TO AN UPTICK IN CLOUD COVERAGE AND A MODIFYING AIR MASS. MIN
TEMPS SUNDAY NIGHT LOW-MID 50S.
MONDAY NIGHT THROUGH TUESDAY NIGHT...
THE PATTERN OF AN UPPER LEVEL RIDGE OVER THE MS VALLEY AND AN UPPER
LEVEL LOW OVER THE CANADIAN MARITIMES WILL MAINTAIN THE NW FLOW
ALOFT OVER THE CAROLINAS. MODEL GUIDANCE CONTINUES TO SUGGEST THE
POTENTIAL FOR A CONVECTIVELY INDUCE VORTICITY MAXIMUM TO
APPROACH/CROSS OUR REGION MONDAY NIGHT THROUGH TUESDAY. TIMING STILL
UNCERTAIN AS THIS FEATURE HAS YET TO DEVELOP SO WILL NEED TO MONITOR
CONDITIONS TO OUR NW (MINNESOTA/WISCONSIN) SUNDAY INTO MONDAY FOR
CONVECTIVE DEVELOPMENT. THIS FEATURE IN TANDEM WITH AN INCREASINGLY
MOIST AIR MASS OVER THE CAROLINAS MAY SUPPORT THE
DEVELOPMENT/SUSTAIN ISOLATED-SCATTERED CONVECTION MONDAY NIGHT INTO
TUESDAY. BASED ON EXPECTED MID-UPPER FLOW...OUR NORTHERN COUNTIES
WILL STAND A BETTER CHANCE OF SEEING ANY CONVECTION VERSUS THE
SOUTHERN COUNTIES. FOR NOW WILL CONTINUE TO MENTION SLIGHT CHANCE
POP AND SEE HOW THE SCENARIO EVOLVES MONDAY. EXPECT WARMER TEMPS
TUESDAY AS LOW LEVEL FLOW BECOME MORE SW....SENDING THICKNESSES BACK
TO NEAR OR ABOVE NORMAL VALUES. MAX TEMPS 80-85. MIN TEMPS MONDAY
NIGHT UPPER 50S TO LOWER 60S...AND LOW-MID 60S TUESDAY NIGHT.
WEDNESDAY THROUGH FRIDAY...
MODEL GUIDANCE CONTINUE TO ADVERTISE AN AMPLIFYING MID-UPPER LEVEL
RIDGE OVER THE DEEP SOUTH-GREAT LAKES...DRIFTING EAST INTO THE
SOUTHEAST U.S. THE WARMING ALOFT ASSOCIATED WITH THE RISING HEIGHTS
WILL INDUCE THE FORMATION OF A MID LEVEL INVERSION...WHICH WILL ACT
AS A CAP OR LID ON THE ATMOSPHERE. THIS SHOULD LIMIT CONVECTIVE
DEVELOPMENT. WILL LIMIT SLIGHT CHANCE POPS TO WEDNESDAY WITH POPS
LESS THAN 20 PERCENT THU-FRI. THE WARMING AIR MASS WILL SEND LOW
LEVEL THICKNESSES INTO THE 1415-1420M RANGE...ABOUT 15M ABOVE
NORMAL. POSITION AND STRENGTH OF THE MID-UPPER LEVEL ANTI-CYCLONE
OVER THE SE U.S. SUGGEST MAX TEMPS WELL ABOVE NORMAL....WITH TEMPS
AROUND 90 PROBABLE THU-FRI. WILL ADVERTISE TEMPS IN THE MID-UPPER
80S FOR NOW SINCE WE ARE TALKING DAYS 7/8.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 110 PM FRIDAY...
A BAND OF BKN CLOUDS WITH CIGS GREATER THAN 4K FT...ALONG WITH SOME
EMBEDDED SPRINKLES...IS QUICKLY MOVING EAST OF I-95. THIS IS
OCCURRING IN CONJUNCTION WITH A SECONDARY BOUNDARY MOVING ACROSS THE
AREA. DRIER AIR AS NOTED BY 20+ DEG DWPT DEPRESSIONS IS FOUND BEHIND
THIS BOUNDARY...ALONG WITH CLEARING SKIES. AS SUCH...LOOK FOR VFR
CONDITIONS TO CONTINUE THROUGH THE 24 HOUR TAF PERIOD. THE OTHER
MAIN CONCERN IS GUSTY NW WINDS. THROUGH SUNSET...LOOK FOR NW WINDS
10-15 KT WITH GUSTS IN THE LOW 20S. AFTER SUNSET AND THROUGH 18Z
SAT...LOOK FOR CLEAR SKIES AND LIGHT WINDS.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH ARE EXPECTED TO BE NEAR RECORD
MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...NP/MWS
SHORT TERM...MWS
LONG TERM...WSS
AVIATION...NP/MWS
CLIMATE...RAH
000
FXUS62 KRAH 241718 CCA
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
110 PM EDT FRI MAY 24 2013
.SYNOPSIS...
CANADIAN HIGH PRESSURE WILL BUILD ACROSS THE REGION THROUGH THE
WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 1025 AM FRIDAY...
12Z ANALYSIS SHOWS THAT CURRENT FORECAST FOR TODAY IS ON TRACK PER
PREV DISCUSSION (INCLUDED BELOW FOR REFERENCE). THE ONLY ADJUSTMENT
WILL BE INCREASING THE NW WINDS A LITTLE SOONER. FORECAST SOUNDINGS
SHOW AVG BL WIND IN THE 24-28KT RANGE ACROSS MUCH OF CENTRAL NC
TODAY...AND THIS IS SUPPORTED BY TRENDS IN THE GSO OBSERVED
SOUNDING. WITH TEMPS ALREADY IN THE UPPER 60S TO AROUND 70...DEEP
MIXING IS UNDERWAY AND WE`RE ALREADY SEEING SFC GUSTS UP TO 25 KT
ACROSS OUR NW ZONES. OTHERWISE...LINGERING LIGHT SHOWERS ACROSS OUR
NE ZONES ARE ADDRESSED IN CURRENT POP/WX GRIDS...SO NO CHANGES
THERE. THIS ACTIVITY IS EXPECTED TO WIND DOWN AND MOVE EAST OF OUR
CWA BY EARLY TO MID AFTERNOON.
PREV DISCUSSION AS OF 230 AM FRIDAY...
AN UPPER LOW WILL AMPLIFY SOUTHEASTWARD FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC REGION TODAY. DESPITE STRONG HEIGHT FALLS AND
DYNAMIC FORCING FOR ASCENT CENTERED OVER VA AND NORTHERN NC IN
ASSOCIATION WITH THIS FEATURE...STRONG LOW LEVEL CAA WILL MOSTLY
OFFSET THIS FORCING...PER DEEP LAYER Q-VECTOR DIAGNOSTICS OVER
CENTRAL NC. AS SUCH...LINGERING MID LEVEL CLOUDINESS THIS MORNING
WILL YIELD TO INCREASINGLY SUBSIDENT AND CLEARING CONDITIONS
THROUGHOUT THE DAY...WITH JUST A SLIGHT CHANCE OF A SHOWER OVER THE
NORTHERN COASTAL THROUGH AROUND 18Z...IN CLOSEST PROXIMITY TO THE
AFOREMENTIONED STRONGEST HEIGHT FALLS ALOFT OVER VA. IT WILL ALSO
BECOME QUITE BREEZY LATE MORNING-MIDDAY ONWARD...AS COOLER AND MUCH
DRIER AIR ASSOCIATED WITH AN INCOMING CANADIAN SURFACE HIGH
OVERSPREADS OUR REGION. DRY ADIABATIC MIXING TO AROUND 6 THOUSAND FT
AND ADDED DOWNSLOPE WARMING SUGGESTS HIGHS IN THE LOWER 70S NW
PIEDMONT TO UPPER 70S SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 300 AM FRIDAY...
HEIGHT RISES IN DRY NORTHWESTERLY DEEP LAYER FLOW WILL DEVELOP
TONIGHT...THEN CONTINUE ON THE EASTERN PERIPHERY OF CANADIAN HIGH
PRESSURE THROUGH THE WEEKEND. PROJECTED LOW LEVEL
THICKNESSES...ACCOUNTING FOR CLEAR BUT CAA MIXING OVERNIGHT...
SUPPORT NEAR RECORD LOWS MOSTLY IN THE LOWER TO MIDDLE 40S...WITH
SOME UPPER 30S POSSIBLE IN SHELTERED (CALM) OUTLYING AREAS.
CLEAR/SUNNY CONDITIONS WILL PERSIST THROUGH SAT EVENING...BEFORE
YIELDING TO INCREASING MID-HIGH CLOUDS IN NW FLOW ALOFT OVERNIGHT.
HIGHS...WITH CONTINUED LOW HUMIDITY...IN THE LOWER TO MIDDLE 70S.
LOWS GENERAL 45 TO 50 DEGREES...WARMEST TRIAD WHERE MID-HIGH CLOUDS
WILL ARRIVE SOONEST (LATE SAT EVENING).
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 315 AM FRIDAY...
PATTERN WILL BE DOMINATED BY UPPER RIDGING NEXT WEEK AS THE UPPER
TROF SHIFTS OFFSHORE AND LIFTS NORTHEAST THIS WEEKEND. TEMPS WILL BE
INITIALLY BELOW NORMAL THROUGH MONDAY AS A COOL SURFACE HIGH
PRESSURE MIGRATES SOUTH OUT OF THE GREAT LAKES AND OVERHEAD ON ITS
WAY OFFSHORE. SKIES SHOULD BE MOSTLY CLEAR SUNDAY AND MONDAY
ALTHOUGH THERE MAY SOME HIGH CLOUDINESS STREAMING IN ALOFT IN THE
NORTHWEST FLOW...DEPENDENT ON THE POSITION AND AMPLITUDE OF THE
UPPER RIDGE. HIGHS SUNDAY WILL BE IN THE 70S...WITH INSOLATION
WARMING THE AIRMASS A FEW DEGREES ON MONDAY...WITH HIGHS 75 TO 80
AFTER A MORNING LOW IN THE LOW TO MID 50S.
SOUTHWESTERLY LOW LEVEL FLOW WITH RISING MID LEVEL HEIGHTS AS THE
UPPER RIDGE SHIFTS EAST WILL ENHANCE THE WARMING TREND INTO LATE
WEEK...WITH HIGH TEMPERATURES RISING A BIT EACH DAY...FROM THE LOWER
80S TUESDAY TO THE MID 80S WEDNESDAY AND THURSDAY. MORNING LOWS WILL
BE MOSTLY IN THE LOWER 60S EACH DAY. WE WILL BE UNDER THE BUILDING
UPPER RIDGE THROUGH THE PERIOD...WHICH WILL LIMIT FORCING WHICH
WOULD PRODUCE WIDESPREAD OR ORGANIZED CONVECTION. AS SUCH...STRONG
INSTABILITY WILL BE NEEDED WHICH WILL LARGELY LIMIT CONVECTION TO A
DIURNAL CYCLE. A POTENTIAL WILD CARD WOULD BE A POTENTIAL FOR
STRONGER MESO-CONVECTIVE SYSTEMS WHICH DEVELOP IN THE MIDWEST/OHIO
VALLEY REGION TO BE HERDED AROUND THE PERIPHERY OF THE RIDGE AND
INTO THE REGION IN THE WEDNESDAY OR THURSDAY TIME FRAME.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 110 PM FRIDAY...
A BAND OF BKN CLOUDS WITH CIGS GREATER THAN 4K FT...ALONG WITH SOME
EMBEDDED SPRINKLES...IS QUICKLY MOVING EAST OF I-95. THIS IS
OCCURRING IN CONJUNCTION WITH A SECONDARY BOUNDARY MOVING ACROSS THE
AREA. DRIER AIR AS NOTED BY 20+ DEG DWPT DEPRESSIONS IS FOUND BEHIND
THIS BOUNDARY...ALONG WITH CLEARING SKIES. AS SUCH...LOOK FOR VFR
CONDITIONS TO CONTINUE THROUGH THE 24 HOUR TAF PERIOD. THE OTHER
MAIN CONCERN IS GUSTY NW WINDS. THROUGH SUNSET...LOOK FOR NW WINDS
10-15 KT WITH GUSTS IN THE LOW 20S. AFTER SUNSET AND THROUGH 18Z
SAT...LOOK FOR CLEAR SKIES AND LIGHT WINDS.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH ARE EXPECTED TO BE NEAR RECORD
MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NP
NEAR TERM...NP/MWS
SHORT TERM...MWS
LONG TERM...MLM
AVIATION...NP/MWS
CLIMATE...MLM
000
FXUS62 KRAH 241432 CCA
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1025 AM EDT FRI MAY 24 2013
.SYNOPSIS...
CANADIAN HIGH PRESSURE WILL BUILD ACROSS THE REGION THROUGH THE
WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 1025 AM FRIDAY...
12Z ANALYSIS SHOWS THAT CURRENT FORECAST FOR TODAY IS ON TRACK PER
PREV DISCUSSION (INCLUDED BELOW FOR REFERENCE). THE ONLY ADJUSTMENT
WILL BE INCREASING THE NW WINDS A LITTLE SOONER. FORECAST SOUNDINGS
SHOW AVG BL WIND IN THE 24-28KT RANGE ACROSS MUCH OF CENTRAL NC
TODAY...AND THIS IS SUPPORTED BY TRENDS IN THE GSO OBSERVED
SOUNDING. WITH TEMPS ALREADY IN THE UPPER 60S TO AROUND 70...DEEP
MIXING IS UNDERWAY AND WE`RE ALREADY SEEING SFC GUSTS UP TO 25 KT
ACROSS OUR NW ZONES. OTHERWISE...LINGERING LIGHT SHOWERS ACROSS OUR
NE ZONES ARE ADDRESSED IN CURRENT POP/WX GRIDS...SO NO CHANGES
THERE. THIS ACTIVITY IS EXPECTED TO WIND DOWN AND MOVE EAST OF OUR
CWA BY EARLY TO MID AFTERNOON.
PREV DISCUSSION AS OF 230 AM FRIDAY...
AN UPPER LOW WILL AMPLIFY SOUTHEASTWARD FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC REGION TODAY. DESPITE STRONG HEIGHT FALLS AND
DYNAMIC FORCING FOR ASCENT CENTERED OVER VA AND NORTHERN NC IN
ASSOCIATION WITH THIS FEATURE...STRONG LOW LEVEL CAA WILL MOSTLY
OFFSET THIS FORCING...PER DEEP LAYER Q-VECTOR DIAGNOSTICS OVER
CENTRAL NC. AS SUCH...LINGERING MID LEVEL CLOUDINESS THIS MORNING
WILL YIELD TO INCREASINGLY SUBSIDENT AND CLEARING CONDITIONS
THROUGHOUT THE DAY...WITH JUST A SLIGHT CHANCE OF A SHOWER OVER THE
NORTHERN COASTAL THROUGH AROUND 18Z...IN CLOSEST PROXIMITY TO THE
AFOREMENTIONED STRONGEST HEIGHT FALLS ALOFT OVER VA. IT WILL ALSO
BECOME QUITE BREEZY LATE MORNING-MIDDAY ONWARD...AS COOLER AND MUCH
DRIER AIR ASSOCIATED WITH AN INCOMING CANADIAN SURFACE HIGH
OVERSPREADS OUR REGION. DRY ADIABATIC MIXING TO AROUND 6 THOUSAND FT
AND ADDED DOWNSLOPE WARMING SUGGESTS HIGHS IN THE LOWER 70S NW
PIEDMONT TO UPPER 70S SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 300 AM FRIDAY...
HEIGHT RISES IN DRY NORTHWESTERLY DEEP LAYER FLOW WILL DEVELOP
TONIGHT...THEN CONTINUE ON THE EASTERN PERIPHERY OF CANADIAN HIGH
PRESSURE THROUGH THE WEEKEND. PROJECTED LOW LEVEL
THICKNESSES...ACCOUNTING FOR CLEAR BUT CAA MIXING OVERNIGHT...
SUPPORT NEAR RECORD LOWS MOSTLY IN THE LOWER TO MIDDLE 40S...WITH
SOME UPPER 30S POSSIBLE IN SHELTERED (CALM) OUTLYING AREAS.
CLEAR/SUNNY CONDITIONS WILL PERSIST THROUGH SAT EVENING...BEFORE
YIELDING TO INCREASING MID-HIGH CLOUDS IN NW FLOW ALOFT OVERNIGHT.
HIGHS...WITH CONTINUED LOW HUMIDITY...IN THE LOWER TO MIDDLE 70S.
LOWS GENERAL 45 TO 50 DEGREES...WARMEST TRIAD WHERE MID-HIGH CLOUDS
WILL ARRIVE SOONEST (LATE SAT EVENING).
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 315 AM FRIDAY...
PATTERN WILL BE DOMINATED BY UPPER RIDGING NEXT WEEK AS THE UPPER
TROF SHIFTS OFFSHORE AND LIFTS NORTHEAST THIS WEEKEND. TEMPS WILL BE
INITIALLY BELOW NORMAL THROUGH MONDAY AS A COOL SURFACE HIGH
PRESSURE MIGRATES SOUTH OUT OF THE GREAT LAKES AND OVERHEAD ON ITS
WAY OFFSHORE. SKIES SHOULD BE MOSTLY CLEAR SUNDAY AND MONDAY
ALTHOUGH THERE MAY SOME HIGH CLOUDINESS STREAMING IN ALOFT IN THE
NORTHWEST FLOW...DEPENDENT ON THE POSITION AND AMPLITUDE OF THE
UPPER RIDGE. HIGHS SUNDAY WILL BE IN THE 70S...WITH INSOLATION
WARMING THE AIRMASS A FEW DEGREES ON MONDAY...WITH HIGHS 75 TO 80
AFTER A MORNING LOW IN THE LOW TO MID 50S.
SOUTHWESTERLY LOW LEVEL FLOW WITH RISING MID LEVEL HEIGHTS AS THE
UPPER RIDGE SHIFTS EAST WILL ENHANCE THE WARMING TREND INTO LATE
WEEK...WITH HIGH TEMPERATURES RISING A BIT EACH DAY...FROM THE LOWER
80S TUESDAY TO THE MID 80S WEDNESDAY AND THURSDAY. MORNING LOWS WILL
BE MOSTLY IN THE LOWER 60S EACH DAY. WE WILL BE UNDER THE BUILDING
UPPER RIDGE THROUGH THE PERIOD...WHICH WILL LIMIT FORCING WHICH
WOULD PRODUCE WIDESPREAD OR ORGANIZED CONVECTION. AS SUCH...STRONG
INSTABILITY WILL BE NEEDED WHICH WILL LARGELY LIMIT CONVECTION TO A
DIURNAL CYCLE. A POTENTIAL WILD CARD WOULD BE A POTENTIAL FOR
STRONGER MESO-CONVECTIVE SYSTEMS WHICH DEVELOP IN THE MIDWEST/OHIO
VALLEY REGION TO BE HERDED AROUND THE PERIPHERY OF THE RIDGE AND
INTO THE REGION IN THE WEDNESDAY OR THURSDAY TIME FRAME.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 730 AM FRIDAY...
HIGH CONFIDENCE OF VFR CONDITIONS WITH CLEARING SKIES TODAY...AFTER
A PERIOD OF LINGERING 7-9 THOUSAND FT CLOUD COVER AND A FEW SHOWERS
THROUGH MIDDAY AROUND KRWI. OTHERWISE...BREEZY NORTHWESTERLY WINDS
ARE EXPECTED TO DEVELOP BETWEEN 14-15Z...AS COOLER AND MUCH DRIER
AIR ASSOCIATED WITH CANADIAN SURFACE HIGH PRESSURE RUSHES INTO THE
REGION. THESE WINDS WILL DIMINISH AROUND SUNSET.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH ARE EXPECTED TO BE NEAR RECORD
MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NP
NEAR TERM...NP/MWS
SHORT TERM...MWS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...MLM
000
FXUS62 KRAH 241130 CCA
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
730 AM EDT FRI MAY 24 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS OUR REGION THIS MORNING...FOLLOWED BY
CANADIAN HIGH PRESSURE TODAY THROUGH THE WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 230 AM FRIDAY...
AN UPPER LOW WILL AMPLIFY SOUTHEASTWARD FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC REGION TODAY. DESPITE STRONG HEIGHT FALLS AND
DYNAMIC FORCING FOR ASCENT CENTERED OVER VA AND NORTHERN NC IN
ASSOCIATION WITH THIS FEATURE...STRONG LOW LEVEL CAA WILL MOSTLY
OFFSET THIS FORCING...PER DEEP LAYER Q-VECTOR DIAGNOSTICS OVER
CENTRAL NC. AS SUCH...LINGERING MID LEVEL CLOUDINESS THIS MORNING
WILL YIELD TO INCREASINGLY SUBSIDENT AND CLEARING CONDITIONS
THROUGHOUT THE DAY...WITH JUST A SLIGHT CHANCE OF A SHOWER OVER THE
NORTHERN COASTAL THROUGH AROUND 18Z...IN CLOSEST PROXIMITY TO THE
AFOREMENTIONED STRONGEST HEIGHT FALLS ALOFT OVER VA. IT WILL ALSO
BECOME QUITE BREEZY LATE MORNING-MIDDAY ONWARD...AS COOLER AND MUCH
DRIER AIR ASSOCIATED WITH AN INCOMING CANADIAN SURFACE HIGH
OVERSPREADS OUR REGION. DRY ADIABATIC MIXING TO AROUND 6 THOUSAND FT
AND ADDED DOWNSLOPE WARMING SUGGESTS HIGHS IN THE LOWER 70S NW
PIEDMONT TO UPPER 70S SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 300 AM FRIDAY...
HEIGHT RISES IN DRY NORTHWESTERLY DEEP LAYER FLOW WILL DEVELOP
TONIGHT...THEN CONTINUE ON THE EASTERN PERIPHERY OF CANADIAN HIGH
PRESSURE THROUGH THE WEEKEND. PROJECTED LOW LEVEL
THICKNESSES...ACCOUNTING FOR CLEAR BUT CAA MIXING OVERNIGHT...
SUPPORT NEAR RECORD LOWS MOSTLY IN THE LOWER TO MIDDLE 40S...WITH
SOME UPPER 30S POSSIBLE IN SHELTERED (CALM) OUTLYING AREAS.
CLEAR/SUNNY CONDITIONS WILL PERSIST THROUGH SAT EVENING...BEFORE
YIELDING TO INCREASING MID-HIGH CLOUDS IN NW FLOW ALOFT OVERNIGHT.
HIGHS...WITH CONTINUED LOW HUMIDITY...IN THE LOWER TO MIDDLE 70S.
LOWS GENERAL 45 TO 50 DEGREES...WARMEST TRIAD WHERE MID-HIGH CLOUDS
WILL ARRIVE SOONEST (LATE SAT EVENING).
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 315 AM FRIDAY...
PATTERN WILL BE DOMINATED BY UPPER RIDGING NEXT WEEK AS THE UPPER
TROF SHIFTS OFFSHORE AND LIFTS NORTHEAST THIS WEEKEND. TEMPS WILL BE
INITIALLY BELOW NORMAL THROUGH MONDAY AS A COOL SURFACE HIGH
PRESSURE MIGRATES SOUTH OUT OF THE GREAT LAKES AND OVERHEAD ON ITS
WAY OFFSHORE. SKIES SHOULD BE MOSTLY CLEAR SUNDAY AND MONDAY
ALTHOUGH THERE MAY SOME HIGH CLOUDINESS STREAMING IN ALOFT IN THE
NORTHWEST FLOW...DEPENDENT ON THE POSITION AND AMPLITUDE OF THE
UPPER RIDGE. HIGHS SUNDAY WILL BE IN THE 70S...WITH INSOLATION
WARMING THE AIRMASS A FEW DEGREES ON MONDAY...WITH HIGHS 75 TO 80
AFTER A MORNING LOW IN THE LOW TO MID 50S.
SOUTHWESTERLY LOW LEVEL FLOW WITH RISING MID LEVEL HEIGHTS AS THE
UPPER RIDGE SHIFTS EAST WILL ENHANCE THE WARMING TREND INTO LATE
WEEK...WITH HIGH TEMPERATURES RISING A BIT EACH DAY...FROM THE LOWER
80S TUESDAY TO THE MID 80S WEDNESDAY AND THURSDAY. MORNING LOWS WILL
BE MOSTLY IN THE LOWER 60S EACH DAY. WE WILL BE UNDER THE BUILDING
UPPER RIDGE THROUGH THE PERIOD...WHICH WILL LIMIT FORCING WHICH
WOULD PRODUCE WIDESPREAD OR ORGANIZED CONVECTION. AS SUCH...STRONG
INSTABILITY WILL BE NEEDED WHICH WILL LARGELY LIMIT CONVECTION TO A
DIURNAL CYCLE. A POTENTIAL WILD CARD WOULD BE A POTENTIAL FOR
STRONGER MESO-CONVECTIVE SYSTEMS WHICH DEVELOP IN THE MIDWEST/OHIO
VALLEY REGION TO BE HERDED AROUND THE PERIPHERY OF THE RIDGE AND
INTO THE REGION IN THE WEDNESDAY OR THURSDAY TIME FRAME.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 730 AM FRIDAY...
HIGH CONFIDENCE OF VFR CONDITIONS WITH CLEARING SKIES TODAY...AFTER
A PERIOD OF LINGERING 7-9 THOUSAND FT CLOUD COVER AND A FEW SHOWERS
THROUGH MIDDAY AROUND KRWI. OTHERWISE...BREEZY NORTHWESTERLY WINDS
ARE EXPECTED TO DEVELOP BETWEEN 14-15Z...AS COOLER AND MUCH DRIER
AIR ASSOCIATED WITH CANADIAN SURFACE HIGH PRESSURE RUSHES INTO THE
REGION. THESE WINDS WILL DIMINISH AROUND SUNSET.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH ARE EXPECTED TO BE NEAR RECORD
MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...MLM
000
FXUS62 KRAH 240822 CCA
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
330 AM EDT FRI MAY 24 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS OUR REGION THIS MORNING...FOLLOWED BY
CANADIAN HIGH PRESSURE TODAY THROUGH THE WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 230 AM FRIDAY...
AN UPPER LOW WILL AMPLIFY SOUTHEASTWARD FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC REGION TODAY. DESPITE STRONG HEIGHT FALLS AND
DYNAMIC FORCING FOR ASCENT CENTERED OVER VA AND NORTHERN NC IN
ASSOCIATION WITH THIS FEATURE...STRONG LOW LEVEL CAA WILL MOSTLY
OFFSET THIS FORCING...PER DEEP LAYER Q-VECTOR DIAGNOSTICS OVER
CENTRAL NC. AS SUCH...LINGERING MID LEVEL CLOUDINESS THIS MORNING
WILL YIELD TO INCREASINGLY SUBSIDENT AND CLEARING CONDITIONS
THROUGHOUT THE DAY...WITH JUST A SLIGHT CHANCE OF A SHOWER OVER THE
NORTHERN COASTAL THROUGH AROUND 18Z...IN CLOSEST PROXIMITY TO THE
AFOREMENTIONED STRONGEST HEIGHT FALLS ALOFT OVER VA. IT WILL ALSO
BECOME QUITE BREEZY LATE MORNING-MIDDAY ONWARD...AS COOLER AND MUCH
DRIER AIR ASSOCIATED WITH AN INCOMING CANADIAN SURFACE HIGH
OVERSPREADS OUR REGION. DRY ADIABATIC MIXING TO AROUND 6 THOUSAND FT
AND ADDED DOWNSLOPE WARMING SUGGESTS HIGHS IN THE LOWER 70S NW
PIEDMONT TO UPPER 70S SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 300 AM FRIDAY...
HEIGHT RISES IN DRY NORTHWESTERLY DEEP LAYER FLOW WILL DEVELOP
TONIGHT...THEN CONTINUE ON THE EASTERN PERIPHERY OF CANADIAN HIGH
PRESSURE THROUGH THE WEEKEND. PROJECTED LOW LEVEL
THICKNESSES...ACCOUNTING FOR CLEAR BUT CAA MIXING OVERNIGHT...
SUPPORT NEAR RECORD LOWS MOSTLY IN THE LOWER TO MIDDLE 40S...WITH
SOME UPPER 30S POSSIBLE IN SHELTERED (CALM) OUTLYING AREAS.
CLEAR/SUNNY CONDITIONS WILL PERSIST THROUGH SAT EVENING...BEFORE
YIELDING TO INCREASING MID-HIGH CLOUDS IN NW FLOW ALOFT OVERNIGHT.
HIGHS...WITH CONTINUED LOW HUMIDITY...IN THE LOWER TO MIDDLE 70S.
LOWS GENERAL 45 TO 50 DEGREES...WARMEST TRIAD WHERE MID-HIGH CLOUDS
WILL ARRIVE SOONEST (LATE SAT EVENING).
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 315 AM FRIDAY...
PATTERN WILL BE DOMINATED BY UPPER RIDGING NEXT WEEK AS THE UPPER
TROF SHIFTS OFFSHORE AND LIFTS NORTHEAST THIS WEEKEND. TEMPS WILL BE
INITIALLY BELOW NORMAL THROUGH MONDAY AS A COOL SURFACE HIGH
PRESSURE MIGRATES SOUTH OUT OF THE GREAT LAKES AND OVERHEAD ON ITS
WAY OFFSHORE. SKIES SHOULD BE MOSTLY CLEAR SUNDAY AND MONDAY
ALTHOUGH THERE MAY SOME HIGH CLOUDINESS STREAMING IN ALOFT IN THE
NORTHWEST FLOW...DEPENDENT ON THE POSITION AND AMPLITUDE OF THE
UPPER RIDGE. HIGHS SUNDAY WILL BE IN THE 70S...WITH INSOLATION
WARMING THE AIRMASS A FEW DEGREES ON MONDAY...WITH HIGHS 75 TO 80
AFTER A MORNING LOW IN THE LOW TO MID 50S.
SOUTHWESTERLY LOW LEVEL FLOW WITH RISING MID LEVEL HEIGHTS AS THE
UPPER RIDGE SHIFTS EAST WILL ENHANCE THE WARMING TREND INTO LATE
WEEK...WITH HIGH TEMPERATURES RISING A BIT EACH DAY...FROM THE LOWER
80S TUESDAY TO THE MID 80S WEDNESDAY AND THURSDAY. MORNING LOWS WILL
BE MOSTLY IN THE LOWER 60S EACH DAY. WE WILL BE UNDER THE BUILDING
UPPER RIDGE THROUGH THE PERIOD...WHICH WILL LIMIT FORCING WHICH
WOULD PRODUCE WIDESPREAD OR ORGANIZED CONVECTION. AS SUCH...STRONG
INSTABILITY WILL BE NEEDED WHICH WILL LARGELY LIMIT CONVECTION TO A
DIURNAL CYCLE. A POTENTIAL WILD CARD WOULD BE A POTENTIAL FOR
STRONGER MESO-CONVECTIVE SYSTEMS WHICH DEVELOP IN THE MIDWEST/OHIO
VALLEY REGION TO BE HERDED AROUND THE PERIPHERY OF THE RIDGE AND
INTO THE REGION IN THE WEDNESDAY OR THURSDAY TIME FRAME.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 210 AM FRIDAY...
JUST A LITTLE LIGHT AND INSIGNIFICANT RAIN REMAINS FROM EARLIER
SHOWERS AND STORMS...AND THIS TOO SHOULD FURTHER DIMINISH DURING THE
NEXT COUPLE OF HOURS IN THE VICINITY OF KFAY/KRDU/KGSO. OTHERWISE...
AREAS OF STRATUS AND FOG ARE LIKELY TO AFFECT KFAY...KRWI...AND
PERHAPS AS FAR WEST AS KRDU THROUGH DAYBREAK...AS LOW LEVEL MOISTURE
WILL REMAIN HIGH AND WINDS LIGHT AHEAD OF A DIFFUSE COLD FRONT
APPROACHING FROM THE WEST. SOME LINGERING 7-9 THOUSAND FT CLOUD
COVER AND A FEW SHOWERS THROUGH MIDDAY AT EASTERN TERMINALS CAN ALSO
BE EXPECTED...WITH OTHERWISE CLEARING CONDITIONS AND A BREEZY AND
GUSTY NORTHWESTERLY WIND DEVELOPING BY AROUND 15Z. WINDS WILL
DIMINISH AROUND SUNSET.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH ARE EXPECTED TO BE NEAR RECORD
MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...ELLIS/WSS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...MLM
000
FXUS62 KRAH 240727
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
330 AM EDT FRI MAY 24 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS OUR REGION THIS MORNING...FOLLOWED BY
CANADIAN HIGH PRESSURE TODAY THROUGH THE WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 230 AM FRIDAY...
AN UPPER LOW WILL AMPLIFY SOUTHEASTWARD FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC REGION TODAY. DESPITE STRONG HEIGHT FALLS AND
DYNAMIC FORCING FOR ASCENT CENTERED OVER VA AND NORTHERN NC IN
ASSOCIATION WITH THIS FEATURE...STRONG LOW LEVEL CAA WILL MOSTLY
OFFSET THIS FORCING...PER DEEP LAYER Q-VECTOR DIAGNOSTICS OVER
CENTRAL NC. AS SUCH...LINGERING MID LEVEL CLOUDINESS THIS MORNING
WILL YIELD TO INCREASINGLY SUBSIDENT AND CLEARING CONDITIONS
THROUGHOUT THE DAY...WITH JUST A SLIGHT CHANCE OF A SHOWER OVER THE
NORTHERN COASTAL THROUGH AROUND 18Z...IN CLOSEST PROXIMITY TO THE
AFOREMENTIONED STRONGEST HEIGHT FALLS ALOFT OVER VA. IT WILL ALSO
BECOME QUITE BREEZY LATE MORNING-MIDDAY ONWARD...AS COOLER AND MUCH
DRIER AIR ASSOCIATED WITH AN INCOMING CANADIAN SURFACE HIGH
OVERSPREADS OUR REGION.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 300 AM FRIDAY...
HEIGHT RISES IN DRY NORTHWESTERLY DEEP LAYER FLOW WILL DEVELOP
TONIGHT...THEN CONTINUE ON THE EASTERN PERIPHERY OF CANADIAN HIGH
PRESSURE THROUGH THE WEEKEND. PROJECTED LOW LEVEL
THICKNESSES...ACCOUNTING FOR CLEAR BUT CAA MIXING OVERNIGHT...
SUPPORT NEAR RECORD LOWS MOSTLY IN THE LOWER TO MIDDLE 40S...WITH
SOME UPPER 30S POSSIBLE IN SHELTERED (CALM) OUTLYING AREAS.
CLEAR/SUNNY CONDITIONS WILL PERSIST THROUGH SAT EVENING...BEFORE
YIELDING TO INCREASING MID-HIGH CLOUDS IN NW FLOW ALOFT OVERNIGHT.
HIGHS...WITH CONTINUED LOW HUMIDITY...IN THE LOWER TO MIDDLE 70S.
LOWS GENERAL 45 TO 50 DEGREES...WARMEST TRIAD WHERE MID-HIGH CLOUDS
WILL ARRIVE SOONEST (LATE SAT EVENING).
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 315 AM FRIDAY...
PATTERN WILL BE DOMINATED BY UPPER RIDGING NEXT WEEK AS THE UPPER
TROF SHIFTS OFFSHORE AND LIFTS NORTHEAST THIS WEEKEND. TEMPS WILL BE
INITIALLY BELOW NORMAL THROUGH MONDAY AS A COOL SURFACE HIGH
PRESSURE MIGRATES SOUTH OUT OF THE GREAT LAKES AND OVERHEAD ON ITS
WAY OFFSHORE. SKIES SHOULD BE MOSTLY CLEAR SUNDAY AND MONDAY
ALTHOUGH THERE MAY SOME HIGH CLOUDINESS STREAMING IN ALOFT IN THE
NORTHWEST FLOW...DEPENDENT ON THE POSITION AND AMPLITUDE OF THE
UPPER RIDGE. HIGHS SUNDAY WILL BE IN THE 70S...WITH INSOLATION
WARMING THE AIRMASS A FEW DEGREES ON MONDAY...WITH HIGHS 75 TO 80
AFTER A MORNING LOW IN THE LOW TO MID 50S.
SOUTHWESTERLY LOW LEVEL FLOW WITH RISING MID LEVEL HEIGHTS AS THE
UPPER RIDGE SHIFTS EAST WILL ENHANCE THE WARMING TREND INTO LATE
WEEK...WITH HIGH TEMPERATURES RISING A BIT EACH DAY...FROM THE LOWER
80S TUESDAY TO THE MID 80S WEDNESDAY AND THURSDAY. MORNING LOWS WILL
BE MOSTLY IN THE LOWER 60S EACH DAY. WE WILL BE UNDER THE BUILDING
UPPER RIDGE THROUGH THE PERIOD...WHICH WILL LIMIT FORCING WHICH
WOULD PRODUCE WIDESPREAD OR ORGANIZED CONVECTION. AS SUCH...STRONG
INSTABILITY WILL BE NEEDED WHICH WILL LARGELY LIMIT CONVECTION TO A
DIURNAL CYCLE. A POTENTIAL WILD CARD WOULD BE A POTENTIAL FOR
STRONGER MESO-CONVECTIVE SYSTEMS WHICH DEVELOP IN THE MIDWEST/OHIO
VALLEY REGION TO BE HERDED AROUND THE PERIPHERY OF THE RIDGE AND
INTO THE REGION IN THE WEDNESDAY OR THURSDAY TIME FRAME.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 210 AM FRIDAY...
JUST A LITTLE LIGHT AND INSIGNIFICANT RAIN REMAINS FROM EARLIER
SHOWERS AND STORMS...AND THIS TOO SHOULD FURTHER DIMINISH DURING THE
NEXT COUPLE OF HOURS IN THE VICINITY OF KFAY/KRDU/KGSO. OTHERWISE...
AREAS OF STRATUS AND FOG ARE LIKELY TO AFFECT KFAY...KRWI...AND
PERHAPS AS FAR WEST AS KRDU THROUGH DAYBREAK...AS LOW LEVEL MOISTURE
WILL REMAIN HIGH AND WINDS LIGHT AHEAD OF A DIFFUSE COLD FRONT
APPROACHING FROM THE WEST. SOME LINGERING 7-9 THOUSAND FT CLOUD
COVER AND A FEW SHOWERS THROUGH MIDDAY AT EASTERN TERMINALS CAN ALSO
BE EXPECTED...WITH OTHERWISE CLEARING CONDITIONS AND A BREEZY AND
GUSTY NORTHWESTERLY WIND DEVELOPING BY AROUND 15Z. WINDS WILL
DIMINISH AROUND SUNSET.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH ARE EXPECTED TO BE NEAR RECORD
MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...ELLIS/WSS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...MLM
000
FXUS62 KRAH 240700
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
300 AM EDT FRI MAY 24 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS OUR REGION THIS MORNING...FOLLOWED BY
CANADIAN HIGH PRESSURE TODAY THROUGH THE WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 230 AM FRIDAY...
AN UPPER LOW WILL AMPLIFY SOUTHEASTWARD FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC REGION TODAY. DESPITE STRONG HEIGHT FALLS AND
DYNAMIC FORCING FOR ASCENT CENTERED OVER VA AND NORTHERN NC IN
ASSOCIATION WITH THIS FEATURE...STRONG LOW LEVEL CAA WILL MOSTLY
OFFSET THIS FORCING...PER DEEP LAYER Q-VECTOR DIAGNOSTICS OVER
CENTRAL NC. AS SUCH...LINGERING MID LEVEL CLOUDINESS THIS MORNING
WILL YIELD TO INCREASINGLY SUBSIDENT AND CLEARING CONDITIONS
THROUGHOUT THE DAY...WITH JUST A SLIGHT CHANCE OF A SHOWER OVER THE
NORTHERN COASTAL THROUGH AROUND 18Z...IN CLOSEST PROXIMITY TO THE
AFOREMENTIONED STRONGEST HEIGHT FALLS ALOFT OVER VA. IT WILL ALSO
BECOME QUITE BREEZY LATE MORNING-MIDDAY ONWARD...AS COOLER AND MUCH
DRIER AIR ASSOCIATED WITH AN INCOMING CANADIAN SURFACE HIGH
OVERSPREADS OUR REGION. DRY ADIABATIC MIXING TO AROUND 6 THOUSAND FT
AND ADDED DOWNSLOPE WARMING SUGGESTS HIGHS IN THE LOWER 70S NW
PIEDMONT TO UPPER 70S SANDHILLS AND SOUTHERN COASTAL PLAIN.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
AS OF 300 AM FRIDAY...
HEIGHT RISES IN DRY NORTHWESTERLY DEEP LAYER FLOW WILL DEVELOP
TONIGHT...THEN CONTINUE ON THE EASTERN PERIPHERY OF CANADIAN HIGH
PRESSURE THROUGH THE WEEKEND. PROJECTED LOW LEVEL
THICKNESSES...ACCOUNTING FOR CLEAR BUT CAA MIXING OVERNIGHT...
SUPPORT NEAR RECORD LOWS MOSTLY IN THE LOWER TO MIDDLE 40S...WITH
SOME UPPER 30S POSSIBLE IN SHELTERED (CALM) OUTLYING AREAS.
CLEAR/SUNNY CONDITIONS WILL PERSIST THROUGH SAT EVENING...BEFORE
YIELDING TO INCREASING MID-HIGH CLOUDS IN NW FLOW ALOFT OVERNIGHT.
HIGHS...WITH CONTINUED LOW HUMIDITY...IN THE LOWER TO MIDDLE 70S.
LOWS GENERAL 45 TO 50 DEGREES...WARMEST TRIAD WHERE MID-HIGH CLOUDS
WILL ARRIVE SOONEST (LATE SAT EVENING).
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...
SUNDAY AND SUNDAY NIGHT...
MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE
1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER
PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS
AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A
CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S
ELSEWHERE.
MONDAY THROUGH THURSDAY...
12Z GFS TRENDING TOWARD THE 00Z ECMWF. THE
ECMWF HELD ONTO THE L/W TROUGH ALONG THE EASTERN SEABOARD RESULTING
IN A SLOWER WARMING TREND WHERE AS THE GFS WITH ITS BUILDING
MID-UPPER HEIGHTS ADVERTISES A QUICKER/MORE NOTABLE WARM-UP. THE
ECMWF SOLUTION OF A LINGERING TROUGH NEAR OR OFFSHORE OF THE NEW
ENGLAND COAST AND AN AMPLIFYING RIDGE OVER THE MS RIVER VALLEY WILL
MAINTAIN A NW FLOW ALOFT OVER CENTRAL NC. THE ECMWF HINTS AT
POSSIBLE DISTURBANCES ASSOCIATED WITH MCS ACTIVITY THAT MAY OCCUR IN
THE UPPER MID WEST/GREAT LAKES TUESDAY-THURSDAY CROSSING OUR REGION.
IF THIS WERE TO OCCUR...COULD SEE A PERIOD OF UNSETTLED WEATHER
ANYTIME BETWEEN WEDNESDAY-THURSDAY. IF GFS WERE TO VERIFY WITH THE
RIDGE BUILDING CLOSER TO HOME...MCS ACTIVITY WILL BE SHUNTED MORE TO
OUR NORTH. FOR NOW...WILL KEEP POPS NO HIGHER THAN 20 PERCENT
TUESDAY INTO THURSDAY. LOW LEVEL THICKNESSES RETURN TO NEAR OR
SLIGHTLY ABOVE NORMAL VALUES TUESDAY ONWARD. WILL HAVE AFTERNOON
TEMPS NEAR 80-LOWER 80S TUESDAY...AND LOW-MID 80S
WEDNESDAY/THURSDAY. AGAIN...IF GFS VERIFIES...WED/THU COULD SEE
TEMPS IN THE UPPER 80S TO NEAR 90.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 210 AM FRIDAY...
JUST A LITTLE LIGHT AND INSIGNIFICANT RAIN REMAINS FROM EARLIER
SHOWERS AND STORMS...AND THIS TOO SHOULD FURTHER DIMINISH DURING THE
NEXT COUPLE OF HOURS IN THE VICINITY OF KFAY/KRDU/KGSO. OTHERWISE...
AREAS OF STRATUS AND FOG ARE LIKELY TO AFFECT KFAY...KRWI...AND
PERHAPS AS FAR WEST AS KRDU THROUGH DAYBREAK...AS LOW LEVEL MOISTURE
WILL REMAIN HIGH AND WINDS LIGHT AHEAD OF A DIFFUSE COLD FRONT
APPROACHING FROM THE WEST. SOME LINGERING 7-9 THOUSAND FT CLOUD
COVER AND A FEW SHOWERS THROUGH MIDDAY AT EASTERN TERMINALS CAN ALSO
BE EXPECTED...WITH OTHERWISE CLEARING CONDITIONS AND A BREEZY AND
GUSTY NORTHWESTERLY WIND DEVELOPING BY AROUND 15Z. WINDS WILL
DIMINISH AROUND SUNSET.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...WSS
AVIATION...MWS
CLIMATE...RAH
000
FXUS62 KRAH 240631
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
231 AM EDT FRI MAY 24 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS OUR REGION THIS MORNING...FOLLOWED BY
CANADIAN HIGH PRESSURE TODAY THROUGH THE WEEKEND.
&&
.NEAR TERM /TODAY/...
AS OF 230 AM FRIDAY...
AN UPPER LOW WILL AMPLIFY SOUTHEASTWARD FROM THE GREAT LAKES TO THE
MIDDLE ATLANTIC REGION TODAY. DESPITE STRONG HEIGHT FALLS AND
DYNAMIC FORCING FOR ASCENT CENTERED OVER VA AND NORTHERN NC IN
ASSOCIATION WITH THIS FEATURE...STRONG LOW LEVEL CAA WILL MOSTLY
OFFSET THIS FORCING...PER DEEP LAYER Q-VECTOR DIAGNOSTICS OVER
CENTRAL NC. AS SUCH...LINGERING MID LEVEL CLOUDINESS THIS MORNING
WILL YIELD TO INCREASINGLY SUBSIDENT AND CLEARING CONDITIONS
THROUGHOUT THE DAY...WITH JUST A SLIGHT CHANCE OF A SHOWER OVER THE
NORTHERN COASTAL THROUGH AROUND 18Z...IN CLOSEST PROXIMITY TO THE
AFOREMENTIONED STRONGEST HEIGHT FALLS ALOFT OVER VA. IT WILL ALSO
BECOME QUITE BREEZY LATE MORNING-MIDDAY ONWARD...AS COOLER AND MUCH
DRIER AIR ASSOCIATED WITH AN INCOMING CANADIAN SURFACE HIGH
OVERSPREADS OUR REGION.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 240 PM THURSDAY...
TONIGHT: WINDS WILL REMAIN BLUSTERY WHICH WILL HELP TO OFFSET
RADIATIONAL COOLING A BIT AS THICKNESSES SUPPORT LOWS NEAR 40
DEGREES BUT WILL GO A BIT CONSERVATIVE IN THE LOWER 40S. STILL VERY
POSSIBLE TO BREAK THE LOW TEMPERATURE RECORDS AT BOTH RDU AND GSO
WHICH ARE BOTH 43 DEGREES. -ELLIS
SATURDAY THROUGH SUNDAY NIGHT...
A DEEP UPPER LEVEL LOW WILL DRIFT NWD ALONG THE NORTHERN MID
ATLANTIC AND NEW ENGLAND COAST THROUGH SUNDAY. DUE TO THE EXTENSIVE
CIRCULATION ASSOCIATED WITH THIS SYSTEM IN TANDEM WITH AN AMPLIFYING
RIDGE OVER THE CENTRAL U.S....THE FLOW ALOFT ACROSS CENTRAL NC WILL
BE NWLY. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE WILL BUILD
SEWD FROM THE GREAT LAKES INTO THE CAROLINAS. THE DEEP N-NW FLOW
WILL RESULT IN A DRY AND COOL HOLIDAY WEEKEND. THICKNESSES SATURDAY
AFTERNOON IN THE 1360S...SOME 30-35M BELOW NORMAL AND SUPPORTIVE OF
TEMPS UPPER 60S TO NEAR 70. ALLOWING FOR THE WARMTH OF A LATE MAY
SUN...FAVOR TEMPS IN THE LOW-MID 70S.
TEMPS WILL COOL OFF QUICKLY SATURDAY EVENING THEN STABILIZE AS MODEL
RH CROSS SECTIONS SUGGEST INCREASING MID-HIGH LEVEL CLOUDINESS AFTER
MIDNIGHT. THESE CLOUDS ASSOCIATED WITH DISTURBANCES IN THE NW FLOW
ALOFT. THIS TYPE OF PATTERN SUPPORTIVE OF OROGRAPHIC ENHANCED
CLOUDINESS...SO THE USUALLY TOO WET GFS MAY BE ONTO SOMETHING. THE
ARRIVAL OF THESE CLOUDS WILL PLAY A ROLE IN DETERMINING MIN TEMPS.
FAVOR COOLEST TEMPS NE WHERE CLOUDS WILL BE LESS/THINNER COMPARED TO
THE WEST-SW. IF CLOUDS ARE SLOW TO ARRIVE OR THIN...MIN TEMPS MAY
END UP BEING 2-3 DEGREES COOLER THAN FORECAST.
MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE
1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER
PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS
AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A
CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S
ELSEWHERE. -WSS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...
12Z GFS TRENDING TOWARD THE 00Z ECMWF. THE ECMWF HELD ONTO THE L/W
TROUGH ALONG THE EASTERN SEABOARD RESULTING IN A SLOWER WARMING
TREND WHERE AS THE GFS WITH ITS BUILDING MID-UPPER HEIGHTS
ADVERTISES A QUICKER/MORE NOTABLE WARM-UP. THE ECMWF SOLUTION OF A
LINGERING TROUGH NEAR OR OFFSHORE OF THE NEW ENGLAND COAST AND AN
AMPLIFYING RIDGE OVER THE MS RIVER VALLEY WILL MAINTAIN A NW FLOW
ALOFT OVER CENTRAL NC. THE ECMWF HINTS AT POSSIBLE DISTURBANCES
ASSOCIATED WITH MCS ACTIVITY THAT MAY OCCUR IN THE UPPER MID
WEST/GREAT LAKES TUESDAY-THURSDAY CROSSING OUR REGION. IF THIS WERE
TO OCCUR...COULD SEE A PERIOD OF UNSETTLED WEATHER ANYTIME BETWEEN
WEDNESDAY-THURSDAY. IF GFS WERE TO VERIFY WITH THE RIDGE BUILDING
CLOSER TO HOME...MCS ACTIVITY WILL BE SHUNTED MORE TO OUR NORTH. FOR
NOW...WILL KEEP POPS NO HIGHER THAN 20 PERCENT TUESDAY INTO
THURSDAY. LOW LEVEL THICKNESSES RETURN TO NEAR OR SLIGHTLY ABOVE
NORMAL VALUES TUESDAY ONWARD. WILL HAVE AFTERNOON TEMPS NEAR 80-LOWER
80S TUESDAY...AND LOW-MID 80S WEDNESDAY/THURSDAY. AGAIN...IF GFS
VERIFIES...WED/THU COULD SEE TEMPS IN THE UPPER 80S TO NEAR 90.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 210 AM FRIDAY...
JUST A LITTLE LIGHT AND INSIGNIFICANT RAIN REMAINS FROM EARLIER
SHOWERS AND STORMS...AND THIS TOO SHOULD FURTHER DIMINISH DURING THE
NEXT COUPLE OF HOURS IN THE VICINITY OF KFAY/KRDU/KGSO. OTHERWISE...
AREAS OF STRATUS AND FOG ARE LIKELY TO AFFECT KFAY...KRWI...AND
PERHAPS AS FAR WEST AS KRDU THROUGH DAYBREAK...AS LOW LEVEL MOISTURE
WILL REMAIN HIGH AND WINDS LIGHT AHEAD OF A DIFFUSE COLD FRONT
APPROACHING FROM THE WEST. SOME LINGERING 7-9 THOUSAND FT CLOUD
COVER AND A FEW SHOWERS THROUGH MIDDAY AT EASTERN TERMINALS CAN ALSO
BE EXPECTED...WITH OTHERWISE CLEARING CONDITIONS AND A BREEZY AND
GUSTY NORTHWESTERLY WIND DEVELOPING BY AROUND 15Z. WINDS WILL
DIMINISH AROUND SUNSET.
OUTLOOK: A STRETCH OF PROLONGED VFR CONDITIONS IN CANADIAN HIGH
PRESSURE WILL PERSIST THROUGH AT LEAST MEMORIAL DAY...WITH THE NEXT
CHANCE OF SUB-VFR CONDITIONS IN FOG TUE MORNING.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...ELLIS/WSS
LONG TERM...WSS
AVIATION...MWS
CLIMATE...RAH
000
FXUS62 KRAH 240218
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1016 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA OVERNIGHT AND EARLY FRIDAY MORNING.
A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE REGION WITH
CLEAR AND COOL CONDITIONS FOR MOST OF THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 PM THURSDAY...
THE EFFECTIVE COLD FRONT IS CURRENTLY MOVING INTO THE NORTHWEST
PIEDMONT... GENERALLY DENOTED BY A LINE OF SHOWERS AND STORMS MOVING
INTO THE NORTHWEST PIEDMONT. THE SPC MESO PAGE IS STILL SHOWING
AROUND 1000 TO 1500 J/KG OF MLCAPE ACROSS OUR WESTERN PIEDMONT THIS
EVENING... OUT AHEAD OF THE LINE OF SHOWERS AND STORMS. HOWEVER...
THE NORTHERN PORTION OF THE LINE IS SHOWING A WEAKENING TREND (WITH
THE SOUTHERN PORTION STILL DEVELOPING AND GETTING READY TO PUSH INTO
OUR SOUTHWEST/WESTERN PIEDMONT)... WITH OUTFLOW PUSHING WELL OUT
AHEAD OF THE LINE... WHERE PERHAPS NOCTURNAL COOLING IS BEGINNING TO
STABILIZE THE BOUNDARY LAYER. THIS IS ALSO WHERE THE SPC MESO PAGE
IS DEPICTING THE LEAST INSTABILITY ACROSS WESTERN PORTIONS OF OUR
AREA (NORTHERN PIEDMONT). THE CURRENT INSTABILITY (MLCAPE) MAX IS
LOCATED ACROSS OUR SOUTHWESTERN PIEDMONT... AROUND 1500 MLCAPE. THIS
IS WHERE ANY MARGINAL SVR THREAT IS EXPECTED TO BE OVER THE NEXT FEW
HOURS (MAIN THREAT ISOLATED STRONG WIND GUSTS)... BEFORE THE SURFACE
COLD FRONT PUSHES THROUGH WESTERN PORTIONS OF OUR AREA FUELED BY A
LEAD MID LEVEL S/W TROUGH... WHICH IS NOW PUSHING EASTWARD OFF OF
THE HIGHER TERRAIN. AS THE LINE PUSHES EASTWARD INTO CENTRAL AND
EASTERN PORTION OF THE RAH CWA... EXPECTED THE LINE WILL WEAKEN
(DECREASE IN INTENSITY AND COVERAGE) WITH THE COOLING BOUNDARY LAYER
AND LACK OF DEEP LAYER SHEAR (GENERALLY 20 TO 25 KTS AT BEST).
THUS... WILL TREND POPS TO HIGH CHANCE/LIKELY WEST TO SLIGHT CHANCE
EAST. EXPECT THE SURFACE COLD FRONT SHOULD BE TO THE EAST OF THE
AREA BY 09Z. THIS SHOULD END ANY CHANCES FOR SHOWERS AND STORMS.
HOWEVER... WE WILL LIKELY CONTINUE TO SEE AT LEAST PARTLY CLOUDY
SKIES ACROSS THE AREA UNTIL THE MAIN MID LEVEL TROUGH AXIS MOVES
THROUGH THE AREA TOMORROW. WILL SHOW LOW TEMPS RANGING FROM THE
UPPER 50S NW TO MID 60S SE.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 240 PM THURSDAY...
FRIDAY AND FRIDAY NIGHT...
THE COLD FRONT WILL SLOWLY MOVE OUT OF THE EASTERN AREAS OF THE CWA
DURING THE EARLY MORNING. AFTER FRONTAL PASSAGE WINDS WILL SHIFT TO
NORTHWESTERLY AND INCREASE IN SPEED TO 15 KNOTS SUSTAINED. A VERY
TALL MIXED LAYER DURING THE AFTERNOON AND THE PASSAGE OF A 30 KNOT
850 JET WILL HELP TRANSPORT SOME OF THOSE WINDS DOWN TO THE SURFACE
AND GUSTS OF 25-30 KNOTS ARE POSSIBLE FRIDAY AFTERNOON. SKIES WILL
GRADUALLY CLEAR OUT AND THICKNESSES SUPPORT HIGH TEMPERATURES IN THE
MID 70S IN MOST LOCATIONS. ON FRIDAY NIGHT WINDS WILL REMAIN
BLUSTERY WHICH WILL HELP TO OFFSET RADIATIONAL COOLING A BIT AS
THICKNESSES SUPPORT LOWS NEAR 40 DEGREES BUT WILL GO A BIT
CONSERVATIVE IN THE LOWER 40S. STILL VERY POSSIBLE TO BREAK THE LOW
TEMPERATURE RECORDS AT BOTH RDU AND GSO WHICH ARE BOTH 43 DEGREES.
-ELLIS
SATURDAY THROUGH SUNDAY NIGHT...
A DEEP UPPER LEVEL LOW WILL DRIFT NWD ALONG THE NORTHERN MID
ATLANTIC AND NEW ENGLAND COAST THROUGH SUNDAY. DUE TO THE EXTENSIVE
CIRCULATION ASSOCIATED WITH THIS SYSTEM IN TANDEM WITH AN AMPLIFYING
RIDGE OVER THE CENTRAL U.S....THE FLOW ALOFT ACROSS CENTRAL NC WILL
BE NWLY. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE WILL BUILD
SEWD FROM THE GREAT LAKES INTO THE CAROLINAS. THE DEEP N-NW FLOW
WILL RESULT IN A DRY AND COOL HOLIDAY WEEKEND. THICKNESSES SATURDAY
AFTERNOON IN THE 1360S...SOME 30-35M BELOW NORMAL AND SUPPORTIVE OF
TEMPS UPPER 60S TO NEAR 70. ALLOWING FOR THE WARMTH OF A LATE MAY
SUN...FAVOR TEMPS IN THE LOW-MID 70S.
TEMPS WILL COOL OFF QUICKLY SATURDAY EVENING THEN STABILIZE AS MODEL
RH CROSS SECTIONS SUGGEST INCREASING MID-HIGH LEVEL CLOUDINESS AFTER
MIDNIGHT. THESE CLOUDS ASSOCIATED WITH DISTURBANCES IN THE NW FLOW
ALOFT. THIS TYPE OF PATTERN SUPPORTIVE OF OROGRAPHIC ENHANCED
CLOUDINESS...SO THE USUALLY TOO WET GFS MAY BE ONTO SOMETHING. THE
ARRIVAL OF THESE CLOUDS WILL PLAY A ROLE IN DETERMINING MIN TEMPS.
FAVOR COOLEST TEMPS NE WHERE CLOUDS WILL BE LESS/THINNER COMPARED TO
THE WEST-SW. IF CLOUDS ARE SLOW TO ARRIVE OR THIN...MIN TEMPS MAY
END UP BEING 2-3 DEGREES COOLER THAN FORECAST.
MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE
1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER
PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS
AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A
CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S
ELSEWHERE. -WSS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...
12Z GFS TRENDING TOWARD THE 00Z ECMWF. THE ECMWF HELD ONTO THE L/W
TROUGH ALONG THE EASTERN SEABOARD RESULTING IN A SLOWER WARMING
TREND WHERE AS THE GFS WITH ITS BUILDING MID-UPPER HEIGHTS
ADVERTISES A QUICKER/MORE NOTABLE WARM-UP. THE ECMWF SOLUTION OF A
LINGERING TROUGH NEAR OR OFFSHORE OF THE NEW ENGLAND COAST AND AN
AMPLIFYING RIDGE OVER THE MS RIVER VALLEY WILL MAINTAIN A NW FLOW
ALOFT OVER CENTRAL NC. THE ECMWF HINTS AT POSSIBLE DISTURBANCES
ASSOCIATED WITH MCS ACTIVITY THAT MAY OCCUR IN THE UPPER MID
WEST/GREAT LAKES TUESDAY-THURSDAY CROSSING OUR REGION. IF THIS WERE
TO OCCUR...COULD SEE A PERIOD OF UNSETTLED WEATHER ANYTIME BETWEEN
WEDNESDAY-THURSDAY. IF GFS WERE TO VERIFY WITH THE RIDGE BUILDING
CLOSER TO HOME...MCS ACTIVITY WILL BE SHUNTED MORE TO OUR NORTH. FOR
NOW...WILL KEEP POPS NO HIGHER THAN 20 PERCENT TUESDAY INTO
THURSDAY. LOW LEVEL THICKNESSES RETURN TO NEAR OR SLIGHTLY ABOVE
NORMAL VALUES TUESDAY ONWARD. WILL HAVE AFTERNOON TEMPS NEAR 80-LOWER
80S TUESDAY...AND LOW-MID 80S WEDNESDAY/THURSDAY. AGAIN...IF GFS
VERIFIES...WED/THU COULD SEE TEMPS IN THE UPPER 80S TO NEAR 90.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 805 PM THURSDAY...
NUMEROUS SHOWERS AND STORMS DEVELOPED BETWEEN KRDU AND KRWI/KFAY
AROUND 18Z...AND HAVE SINCE PUSHED EAST INTO THE COASTAL
PLAIN...LEAVING VFR CONDITIONS ACROSS CENTRAL NC WITH A
SOUTH-SOUTHWESTERLY SURFACE WIND. A SECOND LINE OF STORMS HAS
RECENTLY DEVELOPED AND EXTENDS FROM KRNK TO KTNB AS A COLD FRONT AND
UPPER LEVEL TROUGH APPROACHES FROM THE WEST. IT APPEARS THIS LINE
OF STORMS SHOULD SWEEP ACROSS THE TRIAD AREA BETWEEN 00Z AND
02Z...MOVING TO KRDU BY 03-04Z...AND IF IT HOLDS TOGETHER...REACHING
KFAY/KRWI BY 05-06Z. A STRONG WIND SHIFT TO WEST-NORTHWESTERLY
WINDS WILL ACCOMPANY THE LINE..AND CONFIDENCE IS FAIRLY HIGH THAT
GUSTS WILL EXCEED 30KT AT KGSO/KINT. IN ADDITION..CEILINGS AND VSBYS
MAY BRIEFLY FALL TO TO MVFR. FURTHER EAST...MVFR CEILINGS MAY
DEVELOP AHEAD OF THE LINE DUE TO ABUNDANT LOW LEVEL MOISTURE...BUT A
SWITCH NORTHWESTERLY WINDS SHOULD HELP TO SCOUR CEILINGS BY FRIDAY
MORNING.
VFR CONDITIONS WILL CONTINUE ON FRIDAY WITH WINDS STRENGTHENING TO
NEAR 15KT AND GUSTING TO AT LEAST 25KT AS AN UPPER LEVEL TROUGH
SWINGS ACROSS THE AREA.
OUTLOOK...
VFR CONDITIONS ARE EXPECTED THROUGH THE WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BSD
SHORT TERM...ELLIS/WSS
LONG TERM...WSS
AVIATION...SMITH
CLIMATE...RAH
000
FXUS62 KRAH 240011
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
805 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA OVERNIGHT AND EARLY FRIDAY MORNING.
A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE REGION WITH
CLEAR AND COOL CONDITIONS FOR MOST OF THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM THURSDAY...
UPPER LEVEL TROUGH CONTINUES TO DIG SOUTHWARD THIS AFTERNOON AIDED
BY A 50-75 KNOT UPPER JET OVER THE UPPER MISSISSIPPI VALLEY. THE
SURFACE COLD FRONT IS CURRENTLY MOVING ACROSS CENTRAL TENNESSEE AND
WILL TAKE ITS TIME MOVING ACROSS THE MOUNTAINS THIS EVENING. THE
MAIN 500 MB VORT MAX ASSOCIATED WITH THE FRONT WILL NOT ARRIVE UNTIL
CLOSER TO 00Z. FRONTAL PASSAGE WILL FINALLY OCCUR AFTER 00Z IN THE
NORTHWEST PIEDMONT...CLOSER TO 3Z IN THE TRIANGLE AREA...AND NEAR 6Z
FOR THE I-95 CORRIDOR.
CURRENT RADAR TRENDS SHOW A MYRIAD OF SURFACE BOUNDARIES LEFT OVER
FROM LAST NIGHTS CONVECTION AND DIFFERENTIAL HEATING THIS MORNING.
IN ADDITION A SMALL SHORTWAVE TROUGH IS MOVING NORTHWARD FROM
UPSTATE SOUTH CAROLINA. AT THIS TIME THE BOUNDARY INITIATING THE
MOST CONVECTION SPANS SW TO NE FROM THE ROCKINGHAM AREA TO ROANOKE
RAPIDS. AT THIS TIME INGREDIENTS FOR THUNDERSTORMS ARE A BIT
HEALTHIER THAN IN PREVIOUS DAYS. CURRENTLY THERE IS ABOUT 1000 ML
CAPE IN THE EAST WITH LOW LEVEL LAPSE RATES BETWEEN 7-8. EFFECTIVE
SHEAR IS AROUND 20 KNOTS. RAP SOUNDINGS SHOW VERY TALL SKINNY CAPE
IN THE HAIL GROWTH ZONE MAKING SEVERE HAIL UNLIKELY IN THIS SCENARIO
BUT PEA HAIL IS CERTAINLY POSSIBLE. STRAIGHT HODOGRAPHS WITH 20
KNOTS OF SHEAR SUPPORT A MORE LINEAR MULTICELLULAR CONVECTIVE MODE.
THERE IS A RELATIVELY DRIER LAYER NEAR 800 MB WITH A VERY MODEST
INVERTED V MAKING SEVERE WINDS A LITTLE BIT MORE POSSIBLE THAN IN
PREVIOUS DAYS BUT GUSTS WILL MORE LIKELY TOP OUT IN THE 30-40 KNOT
RANGE. CURRENT SPC ANALYSIS ALSO SHOWS AN AREA OF 500-700 J/KG OF
DCAPE ACROSS THE SOUTH CENTRAL PORTION OF THE CWA. DESPITE
PARAMETERS BEING RELATIVELY BETTER TODAY...MID LEVEL LAPSE RATES ARE
STILL VERY WEAK. OVERALL BULK SHEAR IS LOW. THERE IS ENOUGH LIFT IN
THE MID LEVELS TO SUPPORT MORE LIGHTNING THAN IN PREVIOUS DAYS BUT
ANY SEVERE THREAT WILL BE FAIRLY SUBDUED. AS THE VORT MAX APPROACHES
FROM THE NORTHWEST...DYNAMICS WILL IMPROVE SLIGHTLY AND IF THERE IS
STILL CONVECTION AROUND THE NORTHWEST PIEDMONT WOULD BE THE MOST
LIKELY LOCATION TO SEE SEVERE WEATHER.
WITH SEVERE POTENTIAL LOW...HEAVY RAIN AND FLOODING WILL AGAIN BE
THE LARGEST THREAT. WHILE ONLY A QUARTER TO A HALF OF AN INCH OF
WIDESPREAD PRECIPITATION IS EXPECTED...AREAS RECEIVING HEAVY RAINS
OVER THE PAST FEW DAYS WOULD BE A BIT MORE PRIMED FOR URBAN AND
SMALL STREAM FLOODING. CORFIDI VECTORS SHOW THAT STORMS SHOULD BE
PROGRESSIVE ENOUGH TO AVOID TRAINING BUT ORIENTATION OF INDIVIDUAL
BOUNDARIES COULD ALLOW FOR SOME TRAINING CELLS THIS AFTERNOON.
MOISTURE TRANSPORT...PW VALUES AND SURFACE CONVERGENCE ARE ALL BEST
IN THE COASTAL PLAIN THIS AFTERNOON...MAKING THIS THE MOST LIKELY
LOCATION FOR FLOODING TODAY.
SOUTH SOUTHWESTERLY WINDS TODAY WILL SHIFT TO NORTHWESTERLY AFTER
FRONTAL PASSAGE AND SUSTAINED WINDS WILL ELEVATE TO 10-15 KNOTS.
HIGHS TODAY WILL BE LARGELY DEPENDENT UPON CONVECTION AND CLOUD
COVER BUT IN GENERAL...UPPER 70S TO NEAR 80 IN THE NW AND LOWER TO
MID 80S IN THE SOUTH. LOWS WILL BE DEPENDENT UPON THE TIMING OF THE
FRONTAL PASSAGE UPPER 50S TO NEAR 60 IN THE NW AND MID 60S SE. SOME
MVFR CEILINGS OR VISIBILITIES COULD BE POSSIBLE IN THE EAST BEFORE
MAIN FRONT MOVES THROUGH EARLY FRIDAY MORNING.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 240 PM THURSDAY...
FRIDAY AND FRIDAY NIGHT...
THE COLD FRONT WILL SLOWLY MOVE OUT OF THE EASTERN AREAS OF THE CWA
DURING THE EARLY MORNING. AFTER FRONTAL PASSAGE WINDS WILL SHIFT TO
NORTHWESTERLY AND INCREASE IN SPEED TO 15 KNOTS SUSTAINED. A VERY
TALL MIXED LAYER DURING THE AFTERNOON AND THE PASSAGE OF A 30 KNOT
850 JET WILL HELP TRANSPORT SOME OF THOSE WINDS DOWN TO THE SURFACE
AND GUSTS OF 25-30 KNOTS ARE POSSIBLE FRIDAY AFTERNOON. SKIES WILL
GRADUALLY CLEAR OUT AND THICKNESSES SUPPORT HIGH TEMPERATURES IN THE
MID 70S IN MOST LOCATIONS. ON FRIDAY NIGHT WINDS WILL REMAIN
BLUSTERY WHICH WILL HELP TO OFFSET RADIATIONAL COOLING A BIT AS
THICKNESSES SUPPORT LOWS NEAR 40 DEGREES BUT WILL GO A BIT
CONSERVATIVE IN THE LOWER 40S. STILL VERY POSSIBLE TO BREAK THE LOW
TEMPERATURE RECORDS AT BOTH RDU AND GSO WHICH ARE BOTH 43 DEGREES.
-ELLIS
SATURDAY THROUGH SUNDAY NIGHT...
A DEEP UPPER LEVEL LOW WILL DRIFT NWD ALONG THE NORTHERN MID
ATLANTIC AND NEW ENGLAND COAST THROUGH SUNDAY. DUE TO THE EXTENSIVE
CIRCULATION ASSOCIATED WITH THIS SYSTEM IN TANDEM WITH AN AMPLIFYING
RIDGE OVER THE CENTRAL U.S....THE FLOW ALOFT ACROSS CENTRAL NC WILL
BE NWLY. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE WILL BUILD
SEWD FROM THE GREAT LAKES INTO THE CAROLINAS. THE DEEP N-NW FLOW
WILL RESULT IN A DRY AND COOL HOLIDAY WEEKEND. THICKNESSES SATURDAY
AFTERNOON IN THE 1360S...SOME 30-35M BELOW NORMAL AND SUPPORTIVE OF
TEMPS UPPER 60S TO NEAR 70. ALLOWING FOR THE WARMTH OF A LATE MAY
SUN...FAVOR TEMPS IN THE LOW-MID 70S.
TEMPS WILL COOL OFF QUICKLY SATURDAY EVENING THEN STABILIZE AS MODEL
RH CROSS SECTIONS SUGGEST INCREASING MID-HIGH LEVEL CLOUDINESS AFTER
MIDNIGHT. THESE CLOUDS ASSOCIATED WITH DISTURBANCES IN THE NW FLOW
ALOFT. THIS TYPE OF PATTERN SUPPORTIVE OF OROGRAPHIC ENHANCED
CLOUDINESS...SO THE USUALLY TOO WET GFS MAY BE ONTO SOMETHING. THE
ARRIVAL OF THESE CLOUDS WILL PLAY A ROLE IN DETERMINING MIN TEMPS.
FAVOR COOLEST TEMPS NE WHERE CLOUDS WILL BE LESS/THINNER COMPARED TO
THE WEST-SW. IF CLOUDS ARE SLOW TO ARRIVE OR THIN...MIN TEMPS MAY
END UP BEING 2-3 DEGREES COOLER THAN FORECAST.
MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE
1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER
PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS
AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A
CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S
ELSEWHERE. -WSS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...
12Z GFS TRENDING TOWARD THE 00Z ECMWF. THE ECMWF HELD ONTO THE L/W
TROUGH ALONG THE EASTERN SEABOARD RESULTING IN A SLOWER WARMING
TREND WHERE AS THE GFS WITH ITS BUILDING MID-UPPER HEIGHTS
ADVERTISES A QUICKER/MORE NOTABLE WARM-UP. THE ECMWF SOLUTION OF A
LINGERING TROUGH NEAR OR OFFSHORE OF THE NEW ENGLAND COAST AND AN
AMPLIFYING RIDGE OVER THE MS RIVER VALLEY WILL MAINTAIN A NW FLOW
ALOFT OVER CENTRAL NC. THE ECMWF HINTS AT POSSIBLE DISTURBANCES
ASSOCIATED WITH MCS ACTIVITY THAT MAY OCCUR IN THE UPPER MID
WEST/GREAT LAKES TUESDAY-THURSDAY CROSSING OUR REGION. IF THIS WERE
TO OCCUR...COULD SEE A PERIOD OF UNSETTLED WEATHER ANYTIME BETWEEN
WEDNESDAY-THURSDAY. IF GFS WERE TO VERIFY WITH THE RIDGE BUILDING
CLOSER TO HOME...MCS ACTIVITY WILL BE SHUNTED MORE TO OUR NORTH. FOR
NOW...WILL KEEP POPS NO HIGHER THAN 20 PERCENT TUESDAY INTO
THURSDAY. LOW LEVEL THICKNESSES RETURN TO NEAR OR SLIGHTLY ABOVE
NORMAL VALUES TUESDAY ONWARD. WILL HAVE AFTERNOON TEMPS NEAR 80-LOWER
80S TUESDAY...AND LOW-MID 80S WEDNESDAY/THURSDAY. AGAIN...IF GFS
VERIFIES...WED/THU COULD SEE TEMPS IN THE UPPER 80S TO NEAR 90.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 805 PM THURSDAY...
NUMEROUS SHOWERS AND STORMS DEVELOPED BETWEEN KRDU AND KRWI/KFAY
AROUND 18Z...AND HAVE SINCE PUSHED EAST INTO THE COASTAL
PLAIN...LEAVING VFR CONDITIONS ACROSS CENTRAL NC WITH A
SOUTH-SOUTHWESTERLY SURFACE WIND. A SECOND LINE OF STORMS HAS
RECENTLY DEVELOPED AND EXTENDS FROM KRNK TO KTNB AS A COLD FRONT AND
UPPER LEVEL TROUGH APPROACHES FROM THE WEST. IT APPEARS THIS LINE
OF STORMS SHOULD SWEEP ACROSS THE TRIAD AREA BETWEEN 00Z AND
02Z...MOVING TO KRDU BY 03-04Z...AND IF IT HOLDS TOGETHER...REACHING
KFAY/KRWI BY 05-06Z. A STRONG WIND SHIFT TO WEST-NORTHWESTERLY
WINDS WILL ACCOMPANY THE LINE..AND CONFIDENCE IS FAIRLY HIGH THAT
GUSTS WILL EXCEED 30KT AT KGSO/KINT. IN ADDITION..CEILINGS AND VSBYS
MAY BRIEFLY FALL TO TO MVFR. FURTHER EAST...MVFR CEILINGS MAY
DEVELOP AHEAD OF THE LINE DUE TO ABUNDANT LOW LEVEL MOISTURE...BUT A
SWITCH NORTHWESTERLY WINDS SHOULD HELP TO SCOUR CEILINGS BY FRIDAY
MORNING.
VFR CONDITIONS WILL CONTINUE ON FRIDAY WITH WINDS STRENGTHENING TO
NEAR 15KT AND GUSTING TO AT LEAST 25KT AS AN UPPER LEVEL TROUGH
SWINGS ACROSS THE AREA.
OUTLOOK...
VFR CONDITIONS ARE EXPECTED THROUGH THE WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...ELLIS
SHORT TERM...ELLIS/WSS
LONG TERM...WSS
AVIATION...SMITH
CLIMATE...RAH
000
FXUS62 KRAH 231900
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
300 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY...LEADING TO
UNSETTLED WEATHER MOST OF THE DAY. AFTER FRONTAL PASSAGE
TONIGHT...THE INTRODUCTION OF CANADIAN HIGH PRESSURE WILL BRING
COOLER AND MORE SETTLED CONDITIONS TO THE REGION THROUGH THE HOLIDAY
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM THURSDAY...
UPPER LEVEL TROUGH CONTINUES TO DIG SOUTHWARD THIS AFTERNOON AIDED
BY A 50-75 KNOT UPPER JET OVER THE UPPER MISSISSIPPI VALLEY. THE
SURFACE COLD FRONT IS CURRENTLY MOVING ACROSS CENTRAL TENNESSEE AND
WILL TAKE ITS TIME MOVING ACROSS THE MOUNTAINS THIS EVENING. THE
MAIN 500 MB VORT MAX ASSOCIATED WITH THE FRONT WILL NOT ARRIVE UNTIL
CLOSER TO 00Z. FRONTAL PASSAGE WILL FINALLY OCCUR AFTER 00Z IN THE
NORTHWEST PIEDMONT...CLOSER TO 3Z IN THE TRIANGLE AREA...AND NEAR 6Z
FOR THE I-95 CORRIDOR.
CURRENT RADAR TRENDS SHOW A MYRIAD OF SURFACE BOUNDARIES LEFT OVER
FROM LAST NIGHTS CONVECTION AND DIFFERENTIAL HEATING THIS MORNING.
IN ADDITION A SMALL SHORTWAVE TROUGH IS MOVING NORTHWARD FROM
UPSTATE SOUTH CAROLINA. AT THIS TIME THE BOUNDARY INITIATING THE
MOST CONVECTION SPANS SW TO NE FROM THE ROCKINGHAM AREA TO ROANOKE
RAPIDS. AT THIS TIME INGREDIENTS FOR THUNDERSTORMS ARE A BIT
HEALTHIER THAN IN PREVIOUS DAYS. CURRENTLY THERE IS ABOUT 1000 ML
CAPE IN THE EAST WITH LOW LEVEL LAPSE RATES BETWEEN 7-8. EFFECTIVE
SHEAR IS AROUND 20 KNOTS. RAP SOUNDINGS SHOW VERY TALL SKINNY CAPE
IN THE HAIL GROWTH ZONE MAKING SEVERE HAIL UNLIKELY IN THIS SCENARIO
BUT PEA HAIL IS CERTAINLY POSSIBLE. STRAIGHT HODOGRAPHS WITH 20
KNOTS OF SHEAR SUPPORT A MORE LINEAR MULTICELLULAR CONVECTIVE MODE.
THERE IS A RELATIVELY DRIER LAYER NEAR 800 MB WITH A VERY MODEST
INVERTED V MAKING SEVERE WINDS A LITTLE BIT MORE POSSIBLE THAN IN
PREVIOUS DAYS BUT GUSTS WILL MORE LIKELY TOP OUT IN THE 30-40 KNOT
RANGE. CURRENT SPC ANALYSIS ALSO SHOWS AN AREA OF 500-700 J/KG OF
DCAPE ACROSS THE SOUTH CENTRAL PORTION OF THE CWA. DESPITE
PARAMETERS BEING RELATIVELY BETTER TODAY...MID LEVEL LAPSE RATES ARE
STILL VERY WEAK. OVERALL BULK SHEAR IS LOW. THERE IS ENOUGH LIFT IN
THE MID LEVELS TO SUPPORT MORE LIGHTNING THAN IN PREVIOUS DAYS BUT
ANY SEVERE THREAT WILL BE FAIRLY SUBDUED. AS THE VORT MAX APPROACHES
FROM THE NORTHWEST...DYNAMICS WILL IMPROVE SLIGHTLY AND IF THERE IS
STILL CONVECTION AROUND THE NORTHWEST PIEDMONT WOULD BE THE MOST
LIKELY LOCATION TO SEE SEVERE WEATHER.
WITH SEVERE POTENTIAL LOW...HEAVY RAIN AND FLOODING WILL AGAIN BE
THE LARGEST THREAT. WHILE ONLY A QUARTER TO A HALF OF AN INCH OF
WIDESPREAD PRECIPITATION IS EXPECTED...AREAS RECEIVING HEAVY RAINS
OVER THE PAST FEW DAYS WOULD BE A BIT MORE PRIMED FOR URBAN AND
SMALL STREAM FLOODING. CORFIDI VECTORS SHOW THAT STORMS SHOULD BE
PROGRESSIVE ENOUGH TO AVOID TRAINING BUT ORIENTATION OF INDIVIDUAL
BOUNDARIES COULD ALLOW FOR SOME TRAINING CELLS THIS AFTERNOON.
MOISTURE TRANSPORT...PW VALUES AND SURFACE CONVERGENCE ARE ALL BEST
IN THE COASTAL PLAIN THIS AFTERNOON...MAKING THIS THE MOST LIKELY
LOCATION FOR FLOODING TODAY.
SOUTH SOUTHWESTERLY WINDS TODAY WILL SHIFT TO NORTHWESTERLY AFTER
FRONTAL PASSAGE AND SUSTAINED WINDS WILL ELEVATE TO 10-15 KNOTS.
HIGHS TODAY WILL BE LARGELY DEPENDENT UPON CONVECTION AND CLOUD
COVER BUT IN GENERAL...UPPER 70S TO NEAR 80 IN THE NW AND LOWER TO
MID 80S IN THE SOUTH. LOWS WILL BE DEPENDENT UPON THE TIMING OF THE
FRONTAL PASSAGE UPPER 50S TO NEAR 60 IN THE NW AND MID 60S SE. SOME
MVFR CEILINGS OR VISIBILITIES COULD BE POSSIBLE IN THE EAST BEFORE
MAIN FRONT MOVES THROUGH EARLY FRIDAY MORNING.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 240 PM THURSDAY...
FRIDAY AND FRIDAY NIGHT...
THE COLD FRONT WILL SLOWLY MOVE OUT OF THE EASTERN AREAS OF THE CWA
DURING THE EARLY MORNING. AFTER FRONTAL PASSAGE WINDS WILL SHIFT TO
NORTHWESTERLY AND INCREASE IN SPEED TO 15 KNOTS SUSTAINED. A VERY
TALL MIXED LAYER DURING THE AFTERNOON AND THE PASSAGE OF A 30 KNOT
850 JET WILL HELP TRANSPORT SOME OF THOSE WINDS DOWN TO THE SURFACE
AND GUSTS OF 25-30 KNOTS ARE POSSIBLE FRIDAY AFTERNOON. SKIES WILL
GRADUALLY CLEAR OUT AND THICKNESSES SUPPORT HIGH TEMPERATURES IN THE
MID 70S IN MOST LOCATIONS. ON FRIDAY NIGHT WINDS WILL REMAIN
BLUSTERY WHICH WILL HELP TO OFFSET RADIATIONAL COOLING A BIT AS
THICKNESSES SUPPORT LOWS NEAR 40 DEGREES BUT WILL GO A BIT
CONSERVATIVE IN THE LOWER 40S. STILL VERY POSSIBLE TO BREAK THE LOW
TEMPERATURE RECORDS AT BOTH RDU AND GSO WHICH ARE BOTH 43 DEGREES.
-ELLIS
SATURDAY THROUGH SUNDAY NIGHT...
A DEEP UPPER LEVEL LOW WILL DRIFT NWD ALONG THE NORTHERN MID
ATLANTIC AND NEW ENGLAND COAST THROUGH SUNDAY. DUE TO THE EXTENSIVE
CIRCULATION ASSOCIATED WITH THIS SYSTEM IN TANDEM WITH AN AMPLIFYING
RIDGE OVER THE CENTRAL U.S....THE FLOW ALOFT ACROSS CENTRAL NC WILL
BE NWLY. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE WILL BUILD
SEWD FROM THE GREAT LAKES INTO THE CAROLINAS. THE DEEP N-NW FLOW
WILL RESULT IN A DRY AND COOL HOLIDAY WEEKEND. THICKNESSES SATURDAY
AFTERNOON IN THE 1360S...SOME 30-35M BELOW NORMAL AND SUPPORTIVE OF
TEMPS UPPER 60S TO NEAR 70. ALLOWING FOR THE WARMTH OF A LATE MAY
SUN...FAVOR TEMPS IN THE LOW-MID 70S.
TEMPS WILL COOL OFF QUICKLY SATURDAY EVENING THEN STABILIZE AS MODEL
RH CROSS SECTIONS SUGGEST INCREASING MID-HIGH LEVEL CLOUDINESS AFTER
MIDNIGHT. THESE CLOUDS ASSOCIATED WITH DISTURBANCES IN THE NW FLOW
ALOFT. THIS TYPE OF PATTERN SUPPORTIVE OF OROGRAPHIC ENHANCED
CLOUDINESS...SO THE USUALLY TOO WET GFS MAY BE ONTO SOMETHING. THE
ARRIVAL OF THESE CLOUDS WILL PLAY A ROLE IN DETERMINING MIN TEMPS.
FAVOR COOLEST TEMPS NE WHERE CLOUDS WILL BE LESS/THINNER COMPARED TO
THE WEST-SW. IF CLOUDS ARE SLOW TO ARRIVE OR THIN...MIN TEMPS MAY
END UP BEING 2-3 DEGREES COOLER THAN FORECAST.
MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE
1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER
PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS
AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A
CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S
ELSEWHERE. -WSS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...
12Z GFS TRENDING TOWARD THE 00Z ECMWF. THE ECMWF HELD ONTO THE L/W
TROUGH ALONG THE EASTERN SEABOARD RESULTING IN A SLOWER WARMING
TREND WHERE AS THE GFS WITH ITS BUILDING MID-UPPER HEIGHTS
ADVERTISES A QUICKER/MORE NOTABLE WARM-UP. THE ECMWF SOLUTION OF A
LINGERING TROUGH NEAR OR OFFSHORE OF THE NEW ENGLAND COAST AND AN
AMPLIFYING RIDGE OVER THE MS RIVER VALLEY WILL MAINTAIN A NW FLOW
ALOFT OVER CENTRAL NC. THE ECMWF HINTS AT POSSIBLE DISTURBANCES
ASSOCIATED WITH MCS ACTIVITY THAT MAY OCCUR IN THE UPPER MID
WEST/GREAT LAKES TUESDAY-THURSDAY CROSSING OUR REGION. IF THIS WERE
TO OCCUR...COULD SEE A PERIOD OF UNSETTLED WEATHER ANYTIME BETWEEN
WEDNESDAY-THURSDAY. IF GFS WERE TO VERIFY WITH THE RIDGE BUILDING
CLOSER TO HOME...MCS ACTIVITY WILL BE SHUNTED MORE TO OUR NORTH. FOR
NOW...WILL KEEP POPS NO HIGHER THAN 20 PERCENT TUESDAY INTO
THURSDAY. LOW LEVEL THICKNESSES RETURN TO NEAR OR SLIGHTLY ABOVE
NORMAL VALUES TUESDAY ONWARD. WILL HAVE AFTERNOON TEMPS NEAR 80-LOWER
80S TUESDAY...AND LOW-MID 80S WEDNESDAY/THURSDAY. AGAIN...IF GFS
VERIFIES...WED/THU COULD SEE TEMPS IN THE UPPER 80S TO NEAR 90.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 140 PM THURSDAY...
24 HOUR TAF PERIOD: COMPLICATED LOW CONFIDENCE FORECAST FOR THIS
AFTERNOON. SEVERAL OUTFLOW AND DIFFERENTIAL HEATING BOUNDARIES HAVE
SET UP ACROSS CENTRAL NORTH CAROLINA THIS AFTERNOON. APPROACHING
FROM THE SOUTHWEST IS A SHORTWAVE TROUGH THAT WAS LOCATED OVER
NORTHERN GA THIS MORNING. ALL OF THESE SURFACE BOUNDARIES WILL BE
FOCI FOR THE GENESIS OF SHOWERS AND STORMS THIS AFTERNOON. THE MOST
PROMINENT BOUNDARY AT THIS TIME IS BISECTING THE CWA FROM SW TO NE
AND WILL BE AFFECTING KFAY AND KRWI IN THE NEXT COUPLE OF HOURS.
HEAVY RAIN AND GUSTY WINDS ARE LIKELY WITH THESE STORMS ALONG WITH
IFR/MVFR CEILINGS AND VISIBILITIES. OTHERWISE VFR CONDITIONS WILL
PREVAIL OUTSIDE OF STORMS WITH WINDS OUT OF THE SOUTH SOUTHWEST AT
5-10 KNOTS. LATER THIS AFTERNOON A MORE CONCENTRATED LINE OF SHOWERS
AND STORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL MAKE THEIR
WAY ACROSS THE AREA WITH THE TRIAD TERMINALS AFFECTED JUST BEFORE
0Z. THIS LINE WILL SLOWLY PROGRESS EASTWARD GETTING TO KRDU AND KFAY
IN THE VICINITY OF 3Z AND KRWI CLOSER TO 6Z.
FOR FRIDAY CONDITIONS WILL RETURN TO VFR BUT STRONG GUSTY WINDS WILL
BE THE PROBLEM OF THE DAY WITH 15-20 KNOTS SUSTAINED OUT OF THE
NORTHWEST GUSTING TO 25-30 KNOTS. SKIES WILL GRADUALLY CLEAR
THROUGHOUT THE DAY.
LONG TERM: SATURDAY WILL SEE A PROLONGED RETURN TO VFR CONDITIONS
THROUGH MONDAY MAKING CONDITIONS VERY FAVORABLE FOR GENERAL AVIATION
THROUGH THE EXTENDED MEMORIAL DAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...ELLIS/WSS
LONG TERM...WSS
AVIATION...ELLIS
CLIMATE...RAH
000
FXUS62 KRAH 231842
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
242 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY...LEADING TO
UNSETTLED WEATHER MOST OF THE DAY. AFTER FRONTAL PASSAGE
TONIGHT...THE INTRODUCTION OF CANADIAN HIGH PRESSURE WILL BRING
COOLER AND MORE SETTLED CONDITIONS TO THE REGION THROUGH THE HOLIDAY
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 240 PM THURSDAY...
UPPER LEVEL TROUGH CONTINUES TO DIG SOUTHWARD THIS AFTERNOON AIDED
BY A 50-75 KNOT UPPER JET OVER THE UPPER MISSISSIPPI VALLEY. THE
SURFACE COLD FRONT IS CURRENTLY MOVING ACROSS CENTRAL TENNESSEE AND
WILL TAKE ITS TIME MOVING ACROSS THE MOUNTAINS THIS EVENING. THE
MAIN 500 MB VORT MAX ASSOCIATED WITH THE FRONT WILL NOT ARRIVE UNTIL
CLOSER TO 00Z. FRONTAL PASSAGE WILL FINALLY OCCUR AFTER 00Z IN THE
NORTHWEST PIEDMONT...CLOSER TO 3Z IN THE TRIANGLE AREA...AND NEAR 6Z
FOR THE I-95 CORRIDOR.
CURRENT RADAR TRENDS SHOW A MYRIAD OF SURFACE BOUNDARIES LEFT OVER
FROM LAST NIGHTS CONVECTION AND DIFFERENTIAL HEATING THIS MORNING.
IN ADDITION A SMALL SHORTWAVE TROUGH IS MOVING NORTHWARD FROM
UPSTATE SOUTH CAROLINA. AT THIS TIME THE BOUNDARY INITIATING THE
MOST CONVECTION SPANS SW TO NE FROM THE ROCKINGHAM AREA TO ROANOKE
RAPIDS. AT THIS TIME INGREDIENTS FOR THUNDERSTORMS ARE A BIT
HEALTHIER THAN IN PREVIOUS DAYS. CURRENTLY THERE IS ABOUT 1000 ML
CAPE IN THE EAST WITH LOW LEVEL LAPSE RATES BETWEEN 7-8. EFFECTIVE
SHEAR IS AROUND 20 KNOTS. RAP SOUNDINGS SHOW VERY TALL SKINNY CAPE
IN THE HAIL GROWTH ZONE MAKING SEVERE HAIL UNLIKELY IN THIS SCENARIO
BUT PEA HAIL IS CERTAINLY POSSIBLE. STRAIGHT HODOGRAPHS WITH 20
KNOTS OF SHEAR SUPPORT A MORE LINEAR MULTICELLULAR CONVECTIVE MODE.
THERE IS A RELATIVELY DRIER LAYER NEAR 800 MB WITH A VERY MODEST
INVERTED V MAKING SEVERE WINDS A LITTLE BIT MORE POSSIBLE THAN IN
PREVIOUS DAYS BUT GUSTS WILL MORE LIKELY TOP OUT IN THE 30-40 KNOT
RANGE. CURRENT SPC ANALYSIS ALSO SHOWS AN AREA OF 500-700 J/KG OF
DCAPE ACROSS THE SOUTH CENTRAL PORTION OF THE CWA. DESPITE
PARAMETERS BEING RELATIVELY BETTER TODAY...MID LEVEL LAPSE RATES ARE
STILL VERY WEAK. OVERALL BULK SHEAR IS LOW. THERE IS ENOUGH LIFT IN
THE MID LEVELS TO SUPPORT MORE LIGHTNING THAN IN PREVIOUS DAYS BUT
ANY SEVERE THREAT WILL BE FAIRLY SUBDUED. AS THE VORT MAX APPROACHES
FROM THE NORTHWEST...DYNAMICS WILL IMPROVE SLIGHTLY AND IF THERE IS
STILL CONVECTION AROUND THE NORTHWEST PIEDMONT WOULD BE THE MOST
LIKELY LOCATION TO SEE SEVERE WEATHER.
WITH SEVERE POTENTIAL LOW...HEAVY RAIN AND FLOODING WILL AGAIN BE
THE LARGEST THREAT. WHILE ONLY A QUARTER TO A HALF OF AN INCH OF
WIDESPREAD PRECIPITATION IS EXPECTED...AREAS RECEIVING HEAVY RAINS
OVER THE PAST FEW DAYS WOULD BE A BIT MORE PRIMED FOR URBAN AND
SMALL STREAM FLOODING. CORFIDI VECTORS SHOW THAT STORMS SHOULD BE
PROGRESSIVE ENOUGH TO AVOID TRAINING BUT ORIENTATION OF INDIVIDUAL
BOUNDARIES COULD ALLOW FOR SOME TRAINING CELLS THIS AFTERNOON.
MOISTURE TRANSPORT...PW VALUES AND SURFACE CONVERGENCE ARE ALL BEST
IN THE COASTAL PLAIN THIS AFTERNOON...MAKING THIS THE MOST LIKELY
LOCATION FOR FLOODING TODAY.
SOUTH SOUTHWESTERLY WINDS TODAY WILL SHIFT TO NORTHWESTERLY AFTER
FRONTAL PASSAGE AND SUSTAINED WINDS WILL ELEVATE TO 10-15 KNOTS.
HIGHS TODAY WILL BE LARGELY DEPENDENT UPON CONVECTION AND CLOUD
COVER BUT IN GENERAL...UPPER 70S TO NEAR 80 IN THE NW AND LOWER TO
MID 80S IN THE SOUTH. LOWS WILL BE DEPENDENT UPON THE TIMING OF THE
FRONTAL PASSAGE UPPER 50S TO NEAR 60 IN THE NW AND MID 60S SE. SOME
MVFR CEILINGS OR VISIBILITIES COULD BE POSSIBLE IN THE EAST BEFORE
MAIN FRONT MOVES THROUGH EARLY FRIDAY MORNING.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/...
AS OF 240 PM THURSDAY...
FRIDAY AND FRIDAY NIGHT...
THE COLD FRONT WILL SLOWLY MOVE OUT OF THE EASTERN AREAS OF THE CWA
DURING THE EARLY MORNING. AFTER FRONTAL PASSAGE WINDS WILL SHIFT TO
NORTHWESTERLY AND INCREASE IN SPEED TO 15 KNOTS SUSTAINED. A VERY
TALL MIXED LAYER DURING THE AFTERNOON AND THE PASSAGE OF A 30 KNOT
850 JET WILL HELP TRANSPORT SOME OF THOSE WINDS DOWN TO THE SURFACE
AND GUSTS OF 25-30 KNOTS ARE POSSIBLE FRIDAY AFTERNOON. SKIES WILL
GRADUALLY CLEAR OUT AND THICKNESSES SUPPORT HIGH TEMPERATURES IN THE
MID 70S IN MOST LOCATIONS. ON FRIDAY NIGHT WINDS WILL REMAIN
BLUSTERY WHICH WILL HELP TO OFFSET RADIATIONAL COOLING A BIT AS
THICKNESSES SUPPORT LOWS NEAR 40 DEGREES BUT WILL GO A BIT
CONSERVATIVE IN THE LOWER 40S. STILL VERY POSSIBLE TO BREAK THE LOW
TEMPERATURE RECORDS AT BOTH RDU AND GSO WHICH ARE BOTH 43 DEGREES.
-ELLIS
SATURDAY THROUGH SUNDAY NIGHT...
A DEEP UPPER LEVEL LOW WILL DRIFT NWD ALONG THE NORTHERN MID
ATLANTIC AND NEW ENGLAND COAST THROUGH SUNDAY. DUE TO THE EXTENSIVE
CIRCULATION ASSOCIATED WITH THIS SYSTEM IN TANDEM WITH AN AMPLIFYING
RIDGE OVER THE CENTRAL U.S....THE FLOW ALOFT ACROSS CENTRAL NC WILL
BE NWLY. AT THE SURFACE...COOL CANADIAN HIGH PRESSURE WILL BUILD
SEWD FROM THE GREAT LAKES INTO THE CAROLINAS. THE DEEP N-NW FLOW
WILL RESULT IN A DRY AND COOL HOLIDAY WEEKEND. THICKNESSES SATURDAY
AFTERNOON IN THE 1360S...SOME 30-35M BELOW NORMAL AND SUPPORTIVE OF
TEMPS UPPER 60S TO NEAR 70. ALLOWING FOR THE WARMTH OF A LATE MAY
SUN...FAVOR TEMPS IN THE LOW-MID 70S.
TEMPS WILL COOL OFF QUICKLY SATURDAY EVENING THEN STABILIZE AS MODEL
RH CROSS SECTIONS SUGGEST INCREASING MID-HIGH LEVEL CLOUDINESS AFTER
MIDNIGHT. THESE CLOUDS ASSOCIATED WITH DISTURBANCES IN THE NW FLOW
ALOFT. THIS TYPE OF PATTERN SUPPORTIVE OF OROGRAPHIC ENHANCED
CLOUDINESS...SO THE USUALLY TOO WET GFS MAY BE ONTO SOMETHING. THE
ARRIVAL OF THESE CLOUDS WILL PLAY A ROLE IN DETERMINING MIN TEMPS.
FAVOR COOLEST TEMPS NE WHERE CLOUDS WILL BE LESS/THINNER COMPARED TO
THE WEST-SW. IF CLOUDS ARE SLOW TO ARRIVE OR THIN...MIN TEMPS MAY
END UP BEING 2-3 DEGREES COOLER THAN FORECAST.
MODEST WARM UP EXPECTED SUNDAY AS THICKNESSES RECOVER INTO THE
1370S/LOW 1380S. EXPECT AFTERNOON TEMPS IN THE MID-UPPER 70S UNDER
PARTLY-MOSTLY SUNNY SKIES. SUNDAY NIGHT SHOULD BE A LITTLE MILDER AS
AIR MASS CONTINUES TO MODIFY. MOS GUIDANCE APPEARS TOO WARM BY A
CATEGORY. FAVOR MIN TEMPS NEAR 50 COOLER SPOTS TO LOW-MID 50S
ELSEWHERE. -WSS
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 255 AM THURSDAY...
SATURDAY AND SUNDAY...
A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL
BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL
RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE.
UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME
HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS
BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY
MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO
EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE.
MONDAY THROUGH WEDNESDAY....
THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH
WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE
WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE
PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO
EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING
INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR
SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS
SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY
CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK...
FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS
FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE
LOWER 60S WEDNESDAY MORNING.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 140 PM THURSDAY...
24 HOUR TAF PERIOD: COMPLICATED LOW CONFIDENCE FORECAST FOR THIS
AFTERNOON. SEVERAL OUTFLOW AND DIFFERENTIAL HEATING BOUNDARIES HAVE
SET UP ACROSS CENTRAL NORTH CAROLINA THIS AFTERNOON. APPROACHING
FROM THE SOUTHWEST IS A SHORTWAVE TROUGH THAT WAS LOCATED OVER
NORTHERN GA THIS MORNING. ALL OF THESE SURFACE BOUNDARIES WILL BE
FOCI FOR THE GENESIS OF SHOWERS AND STORMS THIS AFTERNOON. THE MOST
PROMINENT BOUNDARY AT THIS TIME IS BISECTING THE CWA FROM SW TO NE
AND WILL BE AFFECTING KFAY AND KRWI IN THE NEXT COUPLE OF HOURS.
HEAVY RAIN AND GUSTY WINDS ARE LIKELY WITH THESE STORMS ALONG WITH
IFR/MVFR CEILINGS AND VISIBILITIES. OTHERWISE VFR CONDITIONS WILL
PREVAIL OUTSIDE OF STORMS WITH WINDS OUT OF THE SOUTH SOUTHWEST AT
5-10 KNOTS. LATER THIS AFTERNOON A MORE CONCENTRATED LINE OF SHOWERS
AND STORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL MAKE THEIR
WAY ACROSS THE AREA WITH THE TRIAD TERMINALS AFFECTED JUST BEFORE
0Z. THIS LINE WILL SLOWLY PROGRESS EASTWARD GETTING TO KRDU AND KFAY
IN THE VICINITY OF 3Z AND KRWI CLOSER TO 6Z.
FOR FRIDAY CONDITIONS WILL RETURN TO VFR BUT STRONG GUSTY WINDS WILL
BE THE PROBLEM OF THE DAY WITH 15-20 KNOTS SUSTAINED OUT OF THE
NORTHWEST GUSTING TO 25-30 KNOTS. SKIES WILL GRADUALLY CLEAR
THROUGHOUT THE DAY.
LONG TERM: SATURDAY WILL SEE A PROLONGED RETURN TO VFR CONDITIONS
THROUGH MONDAY MAKING CONDITIONS VERY FAVORABLE FOR GENERAL AVIATION
THROUGH THE EXTENDED MEMORIAL DAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...ELLIS/WSS
LONG TERM...MLM
AVIATION...ELLIS
CLIMATE...RAH
000
FXUS62 KRAH 231741
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
141 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY...LEADING TO
UNSETTLED WEATHER MOST OF THE DAY. AFTER FRONTAL PASSAGE
TONIGHT...THE INTRODUCTION OF CANADIAN HIGH PRESSURE WILL BRING
COOLER AND MORE SETTLED CONDITIONS TO THE REGION THROUGH THE HOLIDAY
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM THURSDAY...
EARLIER CONVECTION THAT FORMED ON AN OUTFLOW BOUNDARY OVERNIGHT AND
MOVED ACROSS THE WESTERN HALF OF THE CWA HAS DISSIPATED AT THIS
TIME. THE MAIN FORCING FOR CONVECTION AT THIS HOUR REMAINS ACROSS
THE EAST AND COASTAL PLAIN WHERE THE BEST LOW LEVEL CONVERGENCE AND
MOISTURE TRANSPORT IS AT THIS TIME. THE SURFACE COLD FRONT REMAINS
WELL BACK TO THE WEST AT THIS TIME. FOR THE NEAR TERM...THE FOCUS
FOR CONVECTION WILL BE ON A SHORTWAVE TROUGH MOVING NORTHEAST OUT OF
NORTHERN GA THIS MORNING AS WELL AS WITH SOME LEFT OVER OUTFLOW
BOUNDARIES FROM LAST NIGHTS CONVECTION. SPC MESO-ANALYSIS SHOWS SOME
ML CIN STILL OVER MUCH OF CENTRAL NORTH CAROLINA BUT THIS SHOULD NOT
LAST LONG AS SOME CLEARING OVER THE CENTRAL PART OF THE STATE HAS
LEAD TO MUCH BETTER HEATING SO FAR THIS MORNING. WILL LOOK FOR
SCATTERED CONVECTION TO BEGIN TO BREAK OUT THIS MORNING ALONG THE
AFOREMENTIONED BOUNDARIES AND COVERAGE SHOULD PROGRESSIVELY INCREASE
THROUGHOUT THE DAY. SEVERE POTENTIAL IS STILL LIMITED AS THE BEST
DYNAMICS REMAIN OFF TO THE NORTHEAST. LATER TODAY AS THE FRONT AND
ASSOCIATED UPPER LEVEL TROUGH MOVE CLOSER TO THE AREA BULK SHEAR
SHOULD IMPROVE TO ABOUT 20 KNOTS AND DCAPE WILL INCREASE SHORTLY
BEFORE FRONTAL PASSAGE. IF CONVECTION IS STILL ONGOING LATER THIS
AFTERNOON IN THE NORTHWEST...THIS IS WHERE THE HIGHEST SEVERE WIND
THREAT WILL BE. NOT EXPECTING MUCH IN THE WAY OF HAIL AS CAPE IN THE
HAIL GROWTH ZONE IS VERY LIMITED. RECENT RAINS LAST NIGHT AND IN
DAYS PRIOR WILL MAKE URBAN AND SMALL STREAM FLOODING THE GREATEST
THREAT TODAY BUT THIS SHOULD BE LOCALIZED. OUTSIDE OF CONVECTION
WINDS WILL REMAIN SOUTHERLY AT 5-10 KNOTS WITH SOME GUSTS OF 15-20.
WHILE MUCH OF THE CWA IS VFR AT THIS TIME...MVFR CEILINGS COULD
REMAIN FOR A WHILE ESPECIALLY IN THE WEST WHERE A THICKER CLOUD DECK
EXISTS. TEMPERATURES WILL RISE INTO THE LOW TO MID 80S TODAY.
FRONT WILL CROSS THE AREA TONIGHT AFTER DARK AND MAY NOT EXIT THE
EASTERN PORTION OF THE CWA UNTIL CLOSER TO SUNRISE ON FRIDAY. THIS
WILL LEAVE A GOOD POSSIBILITY FOR FOG AND LOW STRATUS AGAIN
TONIGHT...ESPECIALLY IN THE EAST. IF DEWPOINTS BEGIN TO DROP IN THE
NORTHWEST AFTER FRONTAL PASSAGE THIS MAY NOT BE AN ISSUE. LOWS
TONIGHT WILL BE DEPENDENT ON THE PROGRESSION OF THE FRONT BUT
GENERALLY UPPER 50S TO NEAR 60 IN THE NORTHWEST AND MIDDLE 60S IN
THE SOUTHEAST.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 330 AM THURSDAY...
A SHARP...REINFORCING UPPER TROUGH AXIS WILL PIVOT ACROSS THE MIDDLE
ATLANTIC STATES FRI...THEN OFFSHORE FRI NIGHT. STRONG LOW LEVEL CAA
WILL LARGELY OFFSET THE ASSOCIATED FORCING WITH THE UPPER
TROUGH...SO ASIDE FROM A LINGERING CHANCE OF A SHOWER OR STORM IN A
RESIDUALLY MOIST REGIME OVER THE COASTAL PLAIN THROUGH 1-2
PM...STRONG SUBSIDENCE AND ASSOCIATED CLEAR AND STABLE CONDITIONS
WILL PREVAIL. NOT AS WARM...WITH HIGHS IN THE 70S...AND MUCH COOLER
WITH LOWS IN THE 40S OVERNIGHT...AS CANADIAN/CONTINENTAL POLAR HIGH
PRESSURE BUILDS SOUTHEASTWARD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 255 AM THURSDAY...
SATURDAY AND SUNDAY...
A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL
BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL
RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE.
UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME
HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS
BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY
MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO
EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE.
MONDAY THROUGH WEDNESDAY....
THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH
WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE
WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE
PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO
EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING
INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR
SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS
SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY
CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK...
FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS
FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE
LOWER 60S WEDNESDAY MORNING.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 140 PM THURSDAY...
24 HOUR TAF PERIOD: COMPLICATED LOW CONFIDENCE FORECAST FOR THIS
AFTERNOON. SEVERAL OUTFLOW AND DIFFERENTIAL HEATING BOUNDARIES HAVE
SET UP ACROSS CENTRAL NORTH CAROLINA THIS AFTERNOON. APPROACHING
FROM THE SOUTHWEST IS A SHORTWAVE TROUGH THAT WAS LOCATED OVER
NORTHERN GA THIS MORNING. ALL OF THESE SURFACE BOUNDARIES WILL BE
FOCI FOR THE GENESIS OF SHOWERS AND STORMS THIS AFTERNOON. THE MOST
PROMINENT BOUNDARY AT THIS TIME IS BISECTING THE CWA FROM SW TO NE
AND WILL BE AFFECTING KFAY AND KRWI IN THE NEXT COUPLE OF HOURS.
HEAVY RAIN AND GUSTY WINDS ARE LIKELY WITH THESE STORMS ALONG WITH
IFR/MVFR CEILINGS AND VISIBILITIES. OTHERWISE VFR CONDITIONS WILL
PREVAIL OUTSIDE OF STORMS WITH WINDS OUT OF THE SOUTH SOUTHWEST AT
5-10 KNOTS. LATER THIS AFTERNOON A MORE CONCENTRATED LINE OF SHOWERS
AND STORMS ASSOCIATED WITH THE PRE-FRONTAL TROUGH WILL MAKE THEIR
WAY ACROSS THE AREA WITH THE TRIAD TERMINALS AFFECTED JUST BEFORE
0Z. THIS LINE WILL SLOWLY PROGRESS EASTWARD GETTING TO KRDU AND KFAY
IN THE VICINITY OF 3Z AND KRWI CLOSER TO 6Z.
FOR FRIDAY CONDITIONS WILL RETURN TO VFR BUT STRONG GUSTY WINDS WILL
BE THE PROBLEM OF THE DAY WITH 15-20 KNOTS SUSTAINED OUT OF THE
NORTHWEST GUSTING TO 25-30 KNOTS. SKIES WILL GRADUALLY CLEAR
THROUGHOUT THE DAY.
LONG TERM: SATURDAY WILL SEE A PROLONGED RETURN TO VFR CONDITIONS
THROUGH MONDAY MAKING CONDITIONS VERY FAVORABLE FOR GENERAL AVIATION
THROUGH THE EXTENDED MEMORIAL DAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...MWS
LONG TERM...MLM
AVIATION...ELLIS
CLIMATE...RAH
000
FXUS62 KRAH 231433
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1033 AM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY...LEADING TO
UNSETTLED WEATHER MOST OF THE DAY. AFTER FRONTAL PASSAGE
TONIGHT...THE INTRODUCTION OF CANADIAN HIGH PRESSURE WILL BRING
COOLER AND MORE SETTLED CONDITIONS TO THE REGION THROUGH THE HOLIDAY
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM THURSDAY...
EARLIER CONVECTION THAT FORMED ON AN OUTFLOW BOUNDARY OVERNIGHT AND
MOVED ACROSS THE WESTERN HALF OF THE CWA HAS DISSIPATED AT THIS
TIME. THE MAIN FORCING FOR CONVECTION AT THIS HOUR REMAINS ACROSS
THE EAST AND COASTAL PLAIN WHERE THE BEST LOW LEVEL CONVERGENCE AND
MOISTURE TRANSPORT IS AT THIS TIME. THE SURFACE COLD FRONT REMAINS
WELL BACK TO THE WEST AT THIS TIME. FOR THE NEAR TERM...THE FOCUS
FOR CONVECTION WILL BE ON A SHORTWAVE TROUGH MOVING NORTHEAST OUT OF
NORTHERN GA THIS MORNING AS WELL AS WITH SOME LEFT OVER OUTFLOW
BOUNDARIES FROM LAST NIGHTS CONVECTION. SPC MESO-ANALYSIS SHOWS SOME
ML CIN STILL OVER MUCH OF CENTRAL NORTH CAROLINA BUT THIS SHOULD NOT
LAST LONG AS SOME CLEARING OVER THE CENTRAL PART OF THE STATE HAS
LEAD TO MUCH BETTER HEATING SO FAR THIS MORNING. WILL LOOK FOR
SCATTERED CONVECTION TO BEGIN TO BREAK OUT THIS MORNING ALONG THE
AFOREMENTIONED BOUNDARIES AND COVERAGE SHOULD PROGRESSIVELY INCREASE
THROUGHOUT THE DAY. SEVERE POTENTIAL IS STILL LIMITED AS THE BEST
DYNAMICS REMAIN OFF TO THE NORTHEAST. LATER TODAY AS THE FRONT AND
ASSOCIATED UPPER LEVEL TROUGH MOVE CLOSER TO THE AREA BULK SHEAR
SHOULD IMPROVE TO ABOUT 20 KNOTS AND DCAPE WILL INCREASE SHORTLY
BEFORE FRONTAL PASSAGE. IF CONVECTION IS STILL ONGOING LATER THIS
AFTERNOON IN THE NORTHWEST...THIS IS WHERE THE HIGHEST SEVERE WIND
THREAT WILL BE. NOT EXPECTING MUCH IN THE WAY OF HAIL AS CAPE IN THE
HAIL GROWTH ZONE IS VERY LIMITED. RECENT RAINS LAST NIGHT AND IN
DAYS PRIOR WILL MAKE URBAN AND SMALL STREAM FLOODING THE GREATEST
THREAT TODAY BUT THIS SHOULD BE LOCALIZED. OUTSIDE OF CONVECTION
WINDS WILL REMAIN SOUTHERLY AT 5-10 KNOTS WITH SOME GUSTS OF 15-20.
WHILE MUCH OF THE CWA IS VFR AT THIS TIME...MVFR CEILINGS COULD
REMAIN FOR A WHILE ESPECIALLY IN THE WEST WHERE A THICKER CLOUD DECK
EXISTS. TEMPERATURES WILL RISE INTO THE LOW TO MID 80S TODAY.
FRONT WILL CROSS THE AREA TONIGHT AFTER DARK AND MAY NOT EXIT THE
EASTERN PORTION OF THE CWA UNTIL CLOSER TO SUNRISE ON FRIDAY. THIS
WILL LEAVE A GOOD POSSIBILITY FOR FOG AND LOW STRATUS AGAIN
TONIGHT...ESPECIALLY IN THE EAST. IF DEWPOINTS BEGIN TO DROP IN THE
NORTHWEST AFTER FRONTAL PASSAGE THIS MAY NOT BE AN ISSUE. LOWS
TONIGHT WILL BE DEPENDENT ON THE PROGRESSION OF THE FRONT BUT
GENERALLY UPPER 50S TO NEAR 60 IN THE NORTHWEST AND MIDDLE 60S IN
THE SOUTHEAST.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 330 AM THURSDAY...
A SHARP...REINFORCING UPPER TROUGH AXIS WILL PIVOT ACROSS THE MIDDLE
ATLANTIC STATES FRI...THEN OFFSHORE FRI NIGHT. STRONG LOW LEVEL CAA
WILL LARGELY OFFSET THE ASSOCIATED FORCING WITH THE UPPER
TROUGH...SO ASIDE FROM A LINGERING CHANCE OF A SHOWER OR STORM IN A
RESIDUALLY MOIST REGIME OVER THE COASTAL PLAIN THROUGH 1-2
PM...STRONG SUBSIDENCE AND ASSOCIATED CLEAR AND STABLE CONDITIONS
WILL PREVAIL. NOT AS WARM...WITH HIGHS IN THE 70S...AND MUCH COOLER
WITH LOWS IN THE 40S OVERNIGHT...AS CANADIAN/CONTINENTAL POLAR HIGH
PRESSURE BUILDS SOUTHEASTWARD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 255 AM THURSDAY...
SATURDAY AND SUNDAY...
A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL
BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL
RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE.
UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME
HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS
BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY
MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO
EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE.
MONDAY THROUGH WEDNESDAY....
THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH
WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE
WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE
PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO
EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING
INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR
SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS
SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY
CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK...
FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS
FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE
LOWER 60S WEDNESDAY MORNING.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 640 AM THURSDAY...
A WEAKENING LINE OF SHOWERS SHOULD CONTINUE TO DISSIPATE DURING THE
NEXT COUPLE OF HOURS...LEAVING GENERALLY DRY CONDITIONS THROUGH
MIDDAY. SUB-VFR CEILINGS AT PRESENT WILL ALSO LIFT AND SCATTER TO
VFR DURING THIS TIME. THEREAFTER...DAYTIME HEATING OF THE MOIST AIR
MASS WILL CAUSE SCATTERED TO NUMEROUS SHOWERS AND STORMS TO DEVELOP
THIS AFTERNOON...AND THESE WILL LIKELY PERSIST IN THE VICINITY OF
CENTRAL NC TERMINALS UNTIL A COLD FRONT SWEEPS ACROSS CENTRAL NC
FROM WEST TO EAST BETWEEN 04-06Z AT TRIAD TERMINALS...TO 09-12Z AT
EASTERN ONES. AREAS OF FOG OR LOW STRATUS IN THE MOIST AIR MASS WILL
ALSO BE POSSIBLE AHEAD OF THE COLD FRONT...MOST LIKELY AT KFAY AND
KRWI BETWEEN 06-12Z.
VFR CONDITIONS WILL OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE
THROUGH THE HOLIDAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...MWS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...RAH
000
FXUS62 KRAH 231432
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
642 AM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE WEST TODAY...LEADING TO
UNSETTLED WEATHER MOST OF THE DAY. AFTER FRONTAL PASSAGE
TONIGHT...THE INTRODUCTION OF CANADIAN HIGH PRESSURE WILL BRING
COOLER AND MORE SETTLED CONDITIONS TO THE REGION THROUGH THE HOLIDAY
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM THURSDAY...
EARLIER CONVECTION THAT FORMED ON AN OUTFLOW BOUNDARY OVERNIGHT AND
MOVED ACROSS THE WESTERN HALF OF THE CWA HAS DISSIPATED AT THIS
TIME. THE MAIN FORCING FOR CONVECTION AT THIS HOUR REMAINS ACROSS
THE EAST AND COASTAL PLAIN WHERE THE BEST LOW LEVEL CONVERGENCE AND
MOISTURE TRANSPORT IS AT THIS TIME. THE SURFACE COLD FRONT REMAINS
WELL BACK TO THE WEST AT THIS TIME. FOR THE NEAR TERM...THE FOCUS
FOR CONVECTION WILL BE ON A SHORTWAVE TROUGH MOVING NORTHEAST OUT OF
NORTHERN GA THIS MORNING AS WELL AS WITH SOME LEFT OVER OUTFLOW
BOUNDARIES FROM LAST NIGHTS CONVECTION. SPC MESO-ANALYSIS SHOWS SOME
ML CIN STILL OVER MUCH OF CENTRAL NORTH CAROLINA BUT THIS SHOULD NOT
LAST LONG AS SOME CLEARING OVER THE CENTRAL PART OF THE STATE HAS
LEAD TO MUCH BETTER HEATING SO FAR THIS MORNING. WILL LOOK FOR
SCATTERED CONVECTION TO BEGIN TO BREAK OUT THIS MORNING ALONG THE
AFOREMENTIONED BOUNDARIES AND COVERAGE SHOULD PROGRESSIVELY INCREASE
THROUGHOUT THE DAY. SEVERE POTENTIAL IS STILL LIMITED AS THE BEST
DYNAMICS REMAIN OFF TO THE NORTHEAST. LATER TODAY AS THE FRONT AND
ASSOCIATED UPPER LEVEL TROUGH MOVE CLOSER TO THE AREA BULK SHEAR
SHOULD IMPROVE TO ABOUT 20 KNOTS AND DCAPE WILL INCREASE SHORTLY
BEFORE FRONTAL PASSAGE. IF CONVECTION IS STILL ONGOING LATER THIS
AFTERNOON IN THE NORTHWEST...THIS IS WHERE THE HIGHEST SEVERE WIND
THREAT WILL BE. NOT EXPECTING MUCH IN THE WAY OF HAIL AS CAPE IN THE
HAIL GROWTH ZONE IS VERY LIMITED. RECENT RAINS LAST NIGHT AND IN
DAYS PRIOR WILL MAKE URBAN AND SMALL STREAM FLOODING THE GREATEST
THREAT TODAY BUT THIS SHOULD BE LOCALIZED. OUTSIDE OF CONVECTION
WINDS WILL REMAIN SOUTHERLY AT 5-10 KNOTS WITH SOME GUSTS OF 15-20.
WHILE MUCH OF THE CWA IS VFR AT THIS TIME...MVFR CEILINGS COULD
REMAIN FOR A WHILE ESPECIALLY IN THE WEST WHERE A THICKER CLOUD DECK
EXISTS. TEMPERATURES WILL RISE INTO THE LOW TO MID 80S TODAY.
FRONT WILL CROSS THE AREA TONIGHT AFTER DARK AND MAY NOT EXIT THE
EASTERN PORTION OF THE CWA UNTIL CLOSER TO SUNRISE ON FRIDAY. THIS
WILL LEAVE A GOOD POSSIBILITY FOR FOG AND LOW STRATUS AGAIN
TONIGHT...ESPECIALLY IN THE EAST. IF DEWPOINTS BEGIN TO DROP IN THE
NORTHWEST AFTER FRONTAL PASSAGE THIS MAY NOT BE AN ISSUE. LOWS
TONIGHT WILL BE DEPENDENT ON THE PROGRESSION OF THE FRONT BUT
GENERALLY UPPER 50S TO NEAR 60 IN THE NORTHWEST AND MIDDLE 60S IN
THE SOUTHEAST.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 330 AM THURSDAY...
A SHARP...REINFORCING UPPER TROUGH AXIS WILL PIVOT ACROSS THE MIDDLE
ATLANTIC STATES FRI...THEN OFFSHORE FRI NIGHT. STRONG LOW LEVEL CAA
WILL LARGELY OFFSET THE ASSOCIATED FORCING WITH THE UPPER
TROUGH...SO ASIDE FROM A LINGERING CHANCE OF A SHOWER OR STORM IN A
RESIDUALLY MOIST REGIME OVER THE COASTAL PLAIN THROUGH 1-2
PM...STRONG SUBSIDENCE AND ASSOCIATED CLEAR AND STABLE CONDITIONS
WILL PREVAIL. NOT AS WARM...WITH HIGHS IN THE 70S...AND MUCH COOLER
WITH LOWS IN THE 40S OVERNIGHT...AS CANADIAN/CONTINENTAL POLAR HIGH
PRESSURE BUILDS SOUTHEASTWARD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 255 AM THURSDAY...
SATURDAY AND SUNDAY...
A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL
BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL
RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE.
UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME
HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS
BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY
MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO
EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE.
MONDAY THROUGH WEDNESDAY....
THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH
WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE
WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE
PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO
EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING
INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR
SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS
SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY
CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK...
FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS
FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE
LOWER 60S WEDNESDAY MORNING.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 640 AM THURSDAY...
A WEAKENING LINE OF SHOWERS SHOULD CONTINUE TO DISSIPATE DURING THE
NEXT COUPLE OF HOURS...LEAVING GENERALLY DRY CONDITIONS THROUGH
MIDDAY. SUB-VFR CEILINGS AT PRESENT WILL ALSO LIFT AND SCATTER TO
VFR DURING THIS TIME. THEREAFTER...DAYTIME HEATING OF THE MOIST AIR
MASS WILL CAUSE SCATTERED TO NUMEROUS SHOWERS AND STORMS TO DEVELOP
THIS AFTERNOON...AND THESE WILL LIKELY PERSIST IN THE VICINITY OF
CENTRAL NC TERMINALS UNTIL A COLD FRONT SWEEPS ACROSS CENTRAL NC
FROM WEST TO EAST BETWEEN 04-06Z AT TRIAD TERMINALS...TO 09-12Z AT
EASTERN ONES. AREAS OF FOG OR LOW STRATUS IN THE MOIST AIR MASS WILL
ALSO BE POSSIBLE AHEAD OF THE COLD FRONT...MOST LIKELY AT KFAY AND
KRWI BETWEEN 06-12Z.
VFR CONDITIONS WILL OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE
THROUGH THE HOLIDAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS
SHORT TERM...MWS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...RAH
000
FXUS62 KRAH 231042
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
642 AM EDT THU MAY 23 2013
.SYNOPSIS...
A TROUGH ALOFT AND ACCOMPANYING PRE-FRONTAL SURFACE PRESSURE TROUGH
WILL SETTLE INTO CENTRAL NC TODAY...FOLLOWED BY THE PASSAGE OF A
COLD FRONT TONIGHT. CANADIAN HIGH PRESSURE WILL THEN EXPAND ACROSS
OUR REGION THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM THURSDAY...
TODAY: AT THE BASE OF AN UPPER LOW MIGRATING THROUGH THE LOWER GREAT
LAKES...A NEUTRALLY-TILTED MID-UPPER TROUGH AXIS - AND ASSOCIATED
20-30 METER HEIGHT FALLS - WILL PIVOT EASTWARD INTO CENTRAL NC
TODAY. MEANWHILE AT THE SURFACE...NWP GUIDANCE SUGGESTS A PRONOUNCED
PRE-FRONTAL TROUGH OVER WESTERN GA THIS MORNING WILL DEVELOP
EASTWARD INTO THE WESTERN CAROLINAS THIS AFTERNOON...WHILE LEFT-OVER
OUTFLOW FROM ONGOING CONVECTION OVER THE PIEDMONT WILL ALSO SERVE AS
A POSSIBLE FOCUS...WITH DIURNAL HEATING. THIS ONGOING CONVECTION
SHOULD CONTINUE TO DIMINISH IN COVERAGE AND INTENSITY AS IT EDGES
SLOWLY EASTWARD INTO AN INCREASINGLY STABLE/NOCTURNALLY-COOLED AIR
MASS OVER CENTRAL NC.
SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL CONSEQUENTLY LIKELY
INITIATE INVOF BOTH BOUNDARIES...ONE OVER THE EASTERN PIEDMONT/
SANDHILLS...AND THE OTHER OF HIGHER CONFIDENCE/ PREDICTABILITY OVER
THE FOOTHILLS...WITH SOME TERRAIN ENHANCEMENT PROBABLE WITH THE
LATTER. STORM MOTION TO THE EAST NORTHEAST AT 10-15 KTS WILL ALLOW
THIS LATTER CONVECTION THAT DEVELOPS TO OUR WEST TO MOVE INTO THE
WESTERN PIEDMONT MID-LATE AFTERNOON...THEN EASTWARD ACROSS THE
REMAINDER OF CENTRAL NC DURING THE LATE AFTERNOON AND EVENING HOURS.
MID LEVEL FLOW ON THE ORDER OF 20-25 KTS SUGGESTS MULTI-CELL STORM
ORGANIZATION WITHIN A WEAKLY TO MODERATELY UNSTABLE ENVIRONMENT OVER
THE CAROLINAS...WITH STRONG WIND GUSTS THE PRIMARY HAZARD. SOME
TRAINING OF CONVECTION AND ASSOCIATED QUICK ONE TO TWO INCHES OF
RAIN WILL ALSO BE POSSIBLE...PARTICULARLY BEFORE EVENING...WHEN
FORECAST CORFIDI VECTORS ARE SMALLEST. PROJECTED LOW LEVEL
THICKNESSES OF 5-10 METERS SHY OF THOSE OBSERVED ON WED SUGGEST
HIGHS WITH PARTIAL AFTERNOON SUNSHINE IN THE LOWER TO MIDDLE 80S.
TONIGHT: A COLD FRONT OVER THE WESTERN TN VALLEY THIS MORNING WILL
CREST THE APPALACHIANS THIS EVENING AND CROSS CENTRAL NC OVERNIGHT -
AROUND MIDNIGHT OR SO OVER THE WESTERN PIEDMONT...TO BETWEEN 4 AND 7
AM IN THE COASTAL PLAIN. THE ARRIVAL OF A DRIER AIR MASS WITH
FRONTAL PASSAGE WILL HERALD THE END OF PRECIPITATION CHANCES...
THOUGH CONVECTIVE COVERAGE SHOULD ALREADY BE UNDERGOING A NOCTURNAL
DIMINISHING TREND WITH COOLING. AREAS OF FOG AND/OR LOW STRATUS ARE
ALSO PROBABLE PRIOR TO FRONTAL PASSAGE...MOST LIKELY AND LONGEST
OVER THE FAR EASTERN PIEDMONT/SANDHILLS AND COASTAL PLAIN. LOWS IN
THE LOWER TO MIDDLE 60S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 330 AM THURSDAY...
A SHARP...REINFORCING UPPER TROUGH AXIS WILL PIVOT ACROSS THE MIDDLE
ATLANTIC STATES FRI...THEN OFFSHORE FRI NIGHT. STRONG LOW LEVEL CAA
WILL LARGELY OFFSET THE ASSOCIATED FORCING WITH THE UPPER
TROUGH...SO ASIDE FROM A LINGERING CHANCE OF A SHOWER OR STORM IN A
RESIDUALLY MOIST REGIME OVER THE COASTAL PLAIN THROUGH 1-2
PM...STRONG SUBSIDENCE AND ASSOCIATED CLEAR AND STABLE CONDITIONS
WILL PREVAIL. NOT AS WARM...WITH HIGHS IN THE 70S...AND MUCH COOLER
WITH LOWS IN THE 40S OVERNIGHT...AS CANADIAN/CONTINENTAL POLAR HIGH
PRESSURE BUILDS SOUTHEASTWARD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 255 AM THURSDAY...
SATURDAY AND SUNDAY...
A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL
BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL
RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE.
UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME
HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS
BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY
MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO
EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE.
MONDAY THROUGH WEDNESDAY....
THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH
WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE
WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE
PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO
EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING
INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR
SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS
SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY
CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK...
FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS
FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE
LOWER 60S WEDNESDAY MORNING.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AS OF 640 AM THURSDAY...
A WEAKENING LINE OF SHOWERS SHOULD CONTINUE TO DISSIPATE DURING THE
NEXT COUPLE OF HOURS...LEAVING GENERALLY DRY CONDITIONS THROUGH
MIDDAY. SUB-VFR CEILINGS AT PRESENT WILL ALSO LIFT AND SCATTER TO
VFR DURING THIS TIME. THEREAFTER...DAYTIME HEATING OF THE MOIST AIR
MASS WILL CAUSE SCATTERED TO NUMEROUS SHOWERS AND STORMS TO DEVELOP
THIS AFTERNOON...AND THESE WILL LIKELY PERSIST IN THE VICINITY OF
CENTRAL NC TERMINALS UNTIL A COLD FRONT SWEEPS ACROSS CENTRAL NC
FROM WEST TO EAST BETWEEN 04-06Z AT TRIAD TERMINALS...TO 09-12Z AT
EASTERN ONES. AREAS OF FOG OR LOW STRATUS IN THE MOIST AIR MASS WILL
ALSO BE POSSIBLE AHEAD OF THE COLD FRONT...MOST LIKELY AT KFAY AND
KRWI BETWEEN 06-12Z.
VFR CONDITIONS WILL OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE
THROUGH THE HOLIDAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE
NEAR RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...RAH
000
FXUS62 KRAH 230732
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
332 AM EDT THU MAY 23 2013
.SYNOPSIS...
A TROUGH ALOFT AND ACCOMPANYING PRE-FRONTAL SURFACE PRESSURE TROUGH
WILL SETTLE INTO CENTRAL NC TODAY...FOLLOWED BY THE PASSAGE OF A
COLD FRONT TONIGHT. CANADIAN HIGH PRESSURE WILL THEN EXPAND ACROSS
OUR REGION THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM THURSDAY...
TODAY: AT THE BASE OF AN UPPER LOW MIGRATING THROUGH THE LOWER GREAT
LAKES...A NEUTRALLY-TILTED MID-UPPER TROUGH AXIS - AND ASSOCIATED
20-30 METER HEIGHT FALLS - WILL PIVOT EASTWARD INTO CENTRAL NC
TODAY. MEANWHILE AT THE SURFACE...NWP GUIDANCE SUGGESTS A PRONOUNCED
PRE-FRONTAL TROUGH OVER WESTERN GA THIS MORNING WILL DEVELOP
EASTWARD INTO THE WESTERN CAROLINAS THIS AFTERNOON...WHILE LEFT-OVER
OUTFLOW FROM ONGOING CONVECTION OVER THE PIEDMONT WILL ALSO SERVE AS
A POSSIBLE FOCUS...WITH DIURNAL HEATING. THIS ONGOING CONVECTION
SHOULD CONTINUE TO DIMINISH IN COVERAGE AND INTENSITY AS IT EDGES
SLOWLY EASTWARD INTO AN INCREASINGLY STABLE/NOCTURNALLY-COOLED AIR
MASS OVER CENTRAL NC.
SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL CONSEQUENTLY LIKELY
INITIATE INVOF BOTH BOUNDARIES...ONE OVER THE EASTERN PIEDMONT/
SANDHILLS...AND THE OTHER OF HIGHER CONFIDENCE/ PREDICTABILITY OVER
THE FOOTHILLS...WITH SOME TERRAIN ENHANCEMENT PROBABLE WITH THE
LATTER. STORM MOTION TO THE EAST NORTHEAST AT 10-15 KTS WILL ALLOW
THIS LATTER CONVECTION THAT DEVELOPS TO OUR WEST TO MOVE INTO THE
WESTERN PIEDMONT MID-LATE AFTERNOON...THEN EASTWARD ACROSS THE
REMAINDER OF CENTRAL NC DURING THE LATE AFTERNOON AND EVENING HOURS.
MID LEVEL FLOW ON THE ORDER OF 20-25 KTS SUGGESTS MULTI-CELL STORM
ORGANIZATION WITHIN A WEAKLY TO MODERATELY UNSTABLE ENVIRONMENT OVER
THE CAROLINAS...WITH STRONG WIND GUSTS THE PRIMARY HAZARD. SOME
TRAINING OF CONVECTION AND ASSOCIATED QUICK ONE TO TWO INCHES OF
RAIN WILL ALSO BE POSSIBLE...PARTICULARLY BEFORE EVENING...WHEN
FORECAST CORFIDI VECTORS ARE SMALLEST. PROJECTED LOW LEVEL
THICKNESSES OF 5-10 METERS SHY OF THOSE OBSERVED ON WED SUGGEST
HIGHS WITH PARTIAL AFTERNOON SUNSHINE IN THE LOWER TO MIDDLE 80S.
TONIGHT: A COLD FRONT OVER THE WESTERN TN VALLEY THIS MORNING WILL
CREST THE APPALACHIANS THIS EVENING AND CROSS CENTRAL NC OVERNIGHT -
AROUND MIDNIGHT OR SO OVER THE WESTERN PIEDMONT...TO BETWEEN 4 AND 7
AM IN THE COASTAL PLAIN. THE ARRIVAL OF A DRIER AIR MASS WITH
FRONTAL PASSAGE WILL HERALD THE END OF PRECIPITATION CHANCES...
THOUGH CONVECTIVE COVERAGE SHOULD ALREADY BE UNDERGOING A NOCTURNAL
DIMINISHING TREND WITH COOLING. AREAS OF FOG AND/OR LOW STRATUS ARE
ALSO PROBABLE PRIOR TO FRONTAL PASSAGE...MOST LIKELY AND LONGEST
OVER THE FAR EASTERN PIEDMONT/SANDHILLS AND COASTAL PLAIN. LOWS IN
THE LOWER TO MIDDLE 60S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 330 AM THURSDAY...
A SHARP...REINFORCING UPPER TROUGH AXIS WILL PIVOT ACROSS THE MIDDLE
ATLANTIC STATES FRI...THEN OFFSHORE FRI NIGHT. STRONG LOW LEVEL CAA
WILL LARGELY OFFSET THE ASSOCIATED FORCING WITH THE UPPER
TROUGH...SO ASIDE FROM A LINGERING CHANCE OF A SHOWER OR STORM IN A
RESIDUALLY MOIST REGIME OVER THE COASTAL PLAIN THROUGH 1-2
PM...STRONG SUBSIDENCE AND ASSOCIATED CLEAR AND STABLE CONDITIONS
WILL PREVAIL. NOT AS WARM...WITH HIGHS IN THE 70S...AND MUCH COOLER
WITH LOWS IN THE 40S OVERNIGHT...AS CANADIAN/CONTINENTAL POLAR HIGH
PRESSURE BUILDS SOUTHEASTWARD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 255 AM THURSDAY...
SATURDAY AND SUNDAY...
A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL
BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL
RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE.
UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME
HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS
BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY
MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO
EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE.
MONDAY THROUGH WEDNESDAY....
THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH
WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE
WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE
PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO
EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING
INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR
SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS
SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY
CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK...
FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS
FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE
LOWER 60S WEDNESDAY MORNING.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 205 AM THURSDAY...
A LINE OF SHOWERS AND ISOLATED STORMS THAT EARLIER AFFECTED THE
TRIAD TERMINALS WILL CONTINUE TO MOVE SLOWLY EASTWARD AT AROUND 10
MPH...AFFECTING THE KRDU AREA BETWEEN 8-10Z. A GRADUAL
WEAKENING/DISSIPATING TREND SHOULD OCCUR AS THE AIR MASS CONTINUES
TO STABILIZE WITH NOCTURNAL COOLING...HOWEVER...SO CONFIDENCE OF THE
CONVECTION REACHING THE KFAY AND KRWI AREAS IS LOW. OTHERWISE...A
CONTINUED MOIST AIR MASS WILL PROMOTE A HIGH CHANCE OF LIFR-IFR
CEILINGS THIS MORNING...THOUGH WITH RELATIVE LOWEST CHANCES - AROUND
60 PERCENT - AT TRIAD TERMINALS. THESE CEILINGS WILL LIFT AND
SCATTER TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR
MASS WILL ALSO CAUSE SCATTERED TO NUMEROUS SHOWERS AND STORMS TO
DEVELOP THIS AFTERNOON...AND THESE WILL LIKELY CONTINUE UNTIL A COLD
FRONT SWEEPS ACROSS CENTRAL NC FROM WEST TO EAST BETWEEN 04-06Z AT
TRIAD TERMINALS...TO 09-12Z AT EASTERN ONES. AREAS O FOG OR LOW
STRATUS WILL ALSO BE POSSIBLE AHEAD OF THE COLD FRONT...MOST LIKELY
AT KFAY AND KRWI BETWEEN 06-12Z.
VFR CONDITIONS WILL OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE
THROUGH THE HOLIDAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A
FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...MWS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...RAH
000
FXUS62 KRAH 230723
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
322 AM EDT THU MAY 23 2013
.SYNOPSIS...
A TROUGH ALOFT AND ACCOMPANYING PRE-FRONTAL SURFACE PRESSURE TROUGH
WILL SETTLE INTO CENTRAL NC TODAY...FOLLOWED BY THE PASSAGE OF A
COLD FRONT TONIGHT. CANADIAN HIGH PRESSURE WILL THEN EXPAND ACROSS
OUR REGION THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM THURSDAY...
TODAY: AT THE BASE OF AN UPPER LOW MIGRATING THROUGH THE LOWER GREAT
LAKES...A NEUTRALLY-TILTED MID-UPPER TROUGH AXIS - AND ASSOCIATED
20-30 METER HEIGHT FALLS WILL PIVOT EASTWARD INTO CENTRAL NC TODAY.
MEANWHILE...MULTIPLE BOUNDARIES WILL BE PRESENT AND SERVE AS
CONVECTIVE TRIGGERS. MEANWHILE AT THE SURFACE...NWP GUIDANCE
SUGGESTS A PRONOUNCED PRE-FRONTAL TROUGH OVER WESTERN GA THIS
MORNING WILL DEVELOP EASTWARD INTO THE WESTERN CAROLINAS THIS
AFTERNOON...WHILE LEFT-OVER OUTFLOW FROM ONGOING CONVECTION OVER THE
PIEDMONT WILL ALSO SERVE AS A POSSIBLE FOCUS WITH DIURNAL HEATING.
THIS ONGOING CONVECTION SHOULD CONTINUE TO DIMINISH IN COVERAGE AND
INTENSITY AS IT EDGES SLOWLY EASTWARD INTO AN INCREASINGLY
STABLE/NOCTURNALLY-COOLED AIR MASS OVER CENTRAL NC.
SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL CONSEQUENTLY LIKELY
INITIATE INVOF BOTH BOUNDARIES...ONE OVER THE EASTERN
PIEDMONT/SANDHILLS...AND THE OTHER OF HIGHER CONFIDENCE/
PREDICTABILITY OVER THE FOOTHILLS...WITH SOME TERRAIN ENHANCEMENT
PROBABLE WITH THE LATTER. STORM MOTION TO THE EAST NORTHEAST AT
10-15 KTS WILL ALLOW THIS LATTER CONVECTION THAT DEVELOPS TO OUR
WEST TO MOVE INTO THE WESTERN PIEDMONT MID-LATE AFTERNOON...THEN
EASTWARD ACROSS THE REMAINDER OF CENTRAL NC DURING THE LATE
AFTERNOON AND EVENING HOURS. MID LEVEL FLOW ON THE ORDER OF 20-25
KTS SUGGESTS MULTI-CELL STORM ORGANIZATION WITHIN A WEAKLY TO
MODERATELY UNSTABLE ENVIRONMENT OVER THE CAROLINAS...WITH STRONG
WIND GUSTS THE PRIMARY HAZARD. SOME TRAINING OF CONVECTION AND
ASSOCIATED QUICK ONE TO TWO INCHES OF RAIN WILL ALSO BE
POSSIBLE...PARTICULARLY BEFORE EVENING...WHEN FORECAST CORFIDI
VECTORS ARE SMALLEST. PROJECTED LOW LEVEL THICKNESSES OF 5-10 METERS
SHY OF THOSE OBSERVED ON WED...SUGGESTIVE OF HIGHS WITH PARTIAL
AFTERNOON SUNSHINE IN THE LOWER TO MIDDLE 80S.
TONIGHT: A COLD FRONT OVER THE WESTERN TN VALLEY THIS MORNING WILL
CREST THE APPALACHIANS THIS EVENING AND CROSS CENTRAL NC OVERNIGHT -
AROUND MIDNIGHT OR SO OVER THE WESTERN PIEDMONT...BETWEEN 4 AND 7 AM
IN THE COASTAL PLAIN. THE ARRIVAL OF A DRIER AIR MASS WITH FRONTAL
PASSAGE WILL HERALD THE END OF PRECIPITATION CHANCES...THOUGH
CONVECTIVE COVERAGE SHOULD ALREADY BE UNDERGOING A NOCTURNAL
DIMINISHING TREND WITH COOLING. AREAS OF FOG AND/OR LOW STRATUS ARE
ALSO PROBABLE PRIOR TO FRONTAL PASSAGE...MOST LIKELY AND LONGEST
OVER THE FAR EASTERN PIEDMONT/SANDHILLS AND COASTAL PLAIN. LOWS IN
THE LOWER TO MIDDLE 60S.
&&
.SHORT TERM /FRIDAY AND FRIDAY NIGHT/...
AS OF 310 PM WEDNESDAY...
A DEEP UPPER LEVEL TROUGH WILL SWING ACROSS CENTRAL NC FRIDAY AND
EXIT THE REGION FRIDAY NIGHT. MAY SEE A FEW INSTABILITY SHOWERS WITH
THE PASSAGE OF THIS SYSTEM HOWEVER MODEL RH CROSS SECTIONS DEPICT
THE AIR MASS DRYING OUT APPRECIABLY ABOVE 5000-8000FT BY EARLY
AFTERNOON. FOR NOW WILL LIMIT POPS TO SLIGHT CHANCE. OTHERWISE BRISK
NW FLOW WILL ADVECT COOLER MORE STABLE AIR INTO THE REGION.
SUSTAINED NW WINDS 10-15 MPH WITH GUSTS AROUND 25 MPH PROBABLE. THE
ARRIVAL OF THIS AIR MASS WILL RESULT IN COOLER CONDITIONS WITH
AFTERNOON MAX TEMPS IN THE LOWER 70S NORTH TO UPPER 70S FAR SE.
FRIDAY NIGHT...SKIES WILL CLEAR EARLY THOUGH A STEADY NW SFC WIND
WILL BE SLOW TO SUBSIDE. LOW LEVEL THICKNESSES CLUSTERING AROUND
1340M. HISTORICALLY...THIS SUGGEST MIN TEMPS NEAR 40-LOWER 40S.
FAVOR THE HIGH END OF THIS REGION DUE TO EXPECTED MIXING WELL INTO
THE NIGHT. MIN TEMPS 45-50.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 255 AM THURSDAY...
SATURDAY AND SUNDAY...
A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL
BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL
RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE.
UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME
HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS
BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY
MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO
EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE.
MONDAY THROUGH WEDNESDAY....
THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH
WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE
WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE
PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO
EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING
INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR
SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS
SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY
CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK...
FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS
FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE
LOWER 60S WEDNESDAY MORNING.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 205 AM THURSDAY...
A LINE OF SHOWERS AND ISOLATED STORMS THAT EARLIER AFFECTED THE
TRIAD TERMINALS WILL CONTINUE TO MOVE SLOWLY EASTWARD AT AROUND 10
MPH...AFFECTING THE KRDU AREA BETWEEN 8-10Z. A GRADUAL
WEAKENING/DISSIPATING TREND SHOULD OCCUR AS THE AIR MASS CONTINUES
TO STABILIZE WITH NOCTURNAL COOLING...HOWEVER...SO CONFIDENCE OF THE
CONVECTION REACHING THE KFAY AND KRWI AREAS IS LOW. OTHERWISE...A
CONTINUED MOIST AIR MASS WILL PROMOTE A HIGH CHANCE OF LIFR-IFR
CEILINGS THIS MORNING...THOUGH WITH RELATIVE LOWEST CHANCES - AROUND
60 PERCENT - AT TRIAD TERMINALS. THESE CEILINGS WILL LIFT AND
SCATTER TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR
MASS WILL ALSO CAUSE SCATTERED TO NUMEROUS SHOWERS AND STORMS TO
DEVELOP THIS AFTERNOON...AND THESE WILL LIKELY CONTINUE UNTIL A COLD
FRONT SWEEPS ACROSS CENTRAL NC FROM WEST TO EAST BETWEEN 04-06Z AT
TRIAD TERMINALS...TO 09-12Z AT EASTERN ONES. AREAS O FOG OR LOW
STRATUS WILL ALSO BE POSSIBLE AHEAD OF THE COLD FRONT...MOST LIKELY
AT KFAY AND KRWI BETWEEN 06-12Z.
VFR CONDITIONS WILL OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE
THROUGH THE HOLIDAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A
FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...WSS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...RAH
000
FXUS62 KRAH 230702
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
255 AM EDT THU MAY 23 2013
.SYNOPSIS...
A TROUGH ALOFT AND ACCOMPANYING PRE-FRONTAL SURFACE PRESSURE TROUGH
WILL SETTLE INTO CENTRAL NC TODAY...FOLLOWED BY THE PASSAGE OF A
COLD FRONT TONIGHT. CANADIAN HIGH PRESSURE WILL THEN EXPAND ACROSS
OUR REGION THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 PM WEDNESDAY...
ANY SHOWERS AND THUNDERSTORMS FROM THIS AFTERNOON AND EVENING
ASSOCIATED WITH THE SEA BREEZE AND OUTFLOW ACROSS THE EASTERN
TWO-THIRDS OF THE AREA HAVE DISSIPATED WITH THE LOSS OF DAYTIME
HEATING AND RESULTANT STABILIZING BOUNDARY LAYER. CONVECTION THAT
FIRED ACROSS THE HIGHER TERRAIN TODAY... HAS GENERALLY STAYED TO THE
WEST OF THE REGION WITH A 15 TO 20 KT SOUTH-SOUTHWESTERLY MEAN
STEERING FLOW. HOWEVER... A WEST-NORTHWESTERLY OUTFLOW... GENERATED
FROM THESE CLUSTERS OF SHOWERS AND STORMS THAT ORIGINATED ALONG THE
HIGHER TERRAIN... HAS FINALLY ALLOWED FOR THE DEVELOPMENT OF SHOWERS
AND STORMS ACROSS OUR FAR NORTHWESTERN REACHES OF OUR CWA... ALONG
THE OUTFLOW. THINK THIS OUTFLOW SHOULD SUPPORT AT LEAST SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ACROSS OUR WESTERN PIEDMONT
THROUGH 06/07Z... GIVEN 500 TO 1000 J/KG OF SURFACE BASED CAPE.
THEREAFTER... EXPECT BOUNDARY LAYER COOLING SHOULD YIELD A TREND TO
ISOLATED SHOWERS AT BEST. ANY SIGNIFICANT S/W ENERGY ROTATING
THROUGH THE CYCLONIC FLOW ALOFT FROM THE APPROACHING MID LEVEL
TROUGH WELL TO THE WEST OF THE AREA... INVOF THE MS RIVER THIS
EVENING... IS EXPECTED TO PASS TO THE WEST AND NORTH OF THE REGION
THUS... PLAN TO TRIM POPS TO SLIGHT CHANCE BY EARLY THURSDAY MORNING
ACROSS THE ENTIRE CWA. THIS IS SUPPORTED BY THE LATEST HRRR.
HOWEVER... ITS WORTH NOTING THE LATEST HRRR DOES SHOW SOME SHOWERS
CURRENTLY OFF THE CAROLINA COAST MOVING ONSHORE OVERNIGHT ACROSS THE
COASTAL PLAIN. CURRENT HI-RES MODELS GENERALLY SHOW THIS PRECIP
REMAINING JUST TO THE EAST OF OUR AREA. THUS... WILL KEEP ONLY
SLIGHT CHANCE POPS ACROSS OUR EAST AS WELL. OVERNIGHT LOWS IN THE
MID TO UPPER 60S ARE STILL EXPECTED... WITH GENERALLY PATCHY FOG
(FOG... AT LOCATIONS THAT ARE PICKING UP DECENT SHOWERS/STORMS
ACROSS THE TRIAD NOW) AND WIDESPREAD LOW STATUS.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 PM WEDNESDAY...
A COLD FRONT WILL APPROACH CENTRAL NC FROM THE WEST ON FRIDAY. AS A
DEEP 500 MB TROUGH DIGS SOUTHWARD THROUGH THE OHIO VALLEY. AS FAR AS
TIMING IS CONCERNED...SHOWERS AND THUNDERSTORMS AHEAD OF FRONT WILL
BEGIN TO AFFECT THE TRIAD BY LATE THURSDAY MORNING AND CONTINUE TO
PROGRESS SLOWLY EASTWARD ACROSS THE CWA BY AFTERNOON/EVENING. SEVERE
POTENTIAL WITH THIS SYSTEM WILL BE GREATER THAN THE PAST COUPLE OF
DAYS BUT STILL LOOKS VERY LOW. EFFECTIVE SHEAR WILL BE ABOUT 20
KNOTS SUGGESTING MORE LINEAR THUNDERSTORMS. THIS IS SUPPORTED BY THE
STRAIGHT HODOGRAPHS SHOWN BY NAM FORECAST SOUNDINGS. MID LEVEL LAPSE
RATES WILL BE WEEK ALTHOUGH 1000 ML CAPE OF THE TALL AND SKINNY
VARIETY COULD BE REALIZED BY AFTERNOON. LATER IN THE EVENT DYNAMICS
IMPROVE AS A 30 KNOT 850MB APPROACHES THE NORTHWEST. IT IS UNCLEAR
AT THIS TIME WHETHER OR NOT CONVECTION WILL BE TOO FAR TO THE EAST
TO TAKE ADVANTAGE OF THE INCREASED SHEAR. STORMS LINGERING BACK
TOWARDS THE WEST MAY BE ABLE TO TAKE ADVANTAGE OF AN INCREASED AXIS
OF DCAPE EXPECTED TO MOVE THROUGH THE CWA JUST AFTER 00Z FRIDAY.
THEREFORE IF WE DO ENCOUNTER SEVERE WEATHER TOMORROW...IT WILL MOST
LIKELY BE DAMAGING WINDS AND NOT HAIL. FOR NOW SPC HAS KEPT THE
RALEIGH AREA OUT OF THE SLIGHT RISK AREA FOR TOMORROW. PRECIPITABLE
WATERS WILL BE SIMILAR TO TODAY NEAR 1.5 INCHES BUT QPF WITH FRONTAL
PASSAGE IS ONLY EXPECTED TO BE BETWEEN A QUARTER AND A HALF OF AN
INCH WITH LOCALLY HEAVIER AMOUNTS POSSIBLE IN THUNDERSTORMS.
LOCALIZED FLOODING COULD BE AN ISSUE...ESPECIALLY IN URBAN AREAS
UNDER SLOW MOVING OR TRAINING THUNDERSTORMS. CLOUD COVER SHOULD
OVERSPREAD THE AREA FAIRLY EARLY TOMORROW AND THUS WILL TREND
TOWARDS THE COOLER MET GUIDANCE WITH HIGH TEMPERATURES. UPPER 70S IN
THE NORTHWEST TO LOW 80S SOUTHEAST. AS THE LOWER ATMOSPHERE BEGINS
TO DRY OUT LOW TEMPERATURES IN THE TRIAD SHOULD DIP INTO THE UPPER
50S IN THE NORTHWEST FOR THE FIRST TIME IN SEVERAL DAYS BUT FURTHER
TO THE SOUTHEAST LOWS WILL REMAIN IN THE MIDDLE 60S AS THE FRONT IS
EXPECTED TO FULLY MOVE THROUGH THE EAST UNTIL CLOSER TO 6Z ON FRIDAY.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 255 AM THURSDAY...
SATURDAY AND SUNDAY...
A TERRIFIC WEEKEND IS SHAPING UP AS CANADIAN HIGH PRESSURE WILL
BUILD SOUTH OUT OF THE GREAT LAKES INTO THE EASTERN CONUS. THIS WILL
RESULT IN CLEAR SKIES SATURDAY WITH DRY AND COOLER AIR IN PLACE.
UPPER FLOW WILL BE NORTHWEST AND MODEL CROSS SECTIONS SHOW THAT SOME
HIGH CLOUDINESS COULD MILDLY IMPEDE THE SUNSHINE ON SUNDAY. HIGHS
BOTH DAYS WILL BE MOSTLY IN THE MID 70S. MEANWHILE... SUNDAY
MORNINGS LOW TEMPERATURE WILL BE CONSIDERABLY BELOW NORMAL DUE TO
EXCELLENT RADIATIONAL CONDITIONS...IN THE 45 TO 50 DEGREE RANGE.
MONDAY THROUGH WEDNESDAY....
THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE EARLY NEXT WEEK WHICH
WILL RESULT IN A GRADUAL WARMER AND MOISTER TREND INTO MIDWEEK. WE
WILL BE UNDER A BUILDING LOW AMPLITUDE UPPER RIDGE THROUGH THE
PERIOD WHICH WILL TEND TO SUPPRESS CONVECTION...ESPECIALLY WITH NO
EASILY IDENTIFIABLE FORCING OTHER THAN GENERALLY INCREASING
INSTABILITY WITH LEE TROFFING IN NORTHWEST FLOW AND POTENTIAL FOR
SOME INLAND PENETRATION OF SEA BREEZE CONVECTION IN THE EAST. AS
SUCH...WILL NOT MEDDLE WITH ONGOING SLIGHT CHANCE FOR LATE DAY
CONVECTION MONDAY THROUGH WEDNESDAY. TEMPS WILL BE ON THE UPTICK...
FROM 75 TO 80 ON MONDAY RISING TO 80 TO 85 ON WEDNESDAY...WITH MINS
FOLLOWING A SIMILAR TREND...FROM THE MID 50S MONDAY MORNING TO THE
LOWER 60S WEDNESDAY MORNING.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 205 AM THURSDAY...
A LINE OF SHOWERS AND ISOLATED STORMS THAT EARLIER AFFECTED THE
TRIAD TERMINALS WILL CONTINUE TO MOVE SLOWLY EASTWARD AT AROUND 10
MPH...AFFECTING THE KRDU AREA BETWEEN 8-10Z. A GRADUAL
WEAKENING/DISSIPATING TREND SHOULD OCCUR AS THE AIR MASS CONTINUES
TO STABILIZE WITH NOCTURNAL COOLING...HOWEVER...SO CONFIDENCE OF THE
CONVECTION REACHING THE KFAY AND KRWI AREAS IS LOW. OTHERWISE...A
CONTINUED MOIST AIR MASS WILL PROMOTE A HIGH CHANCE OF LIFR-IFR
CEILINGS THIS MORNING...THOUGH WITH RELATIVE LOWEST CHANCES - AROUND
60 PERCENT - AT TRIAD TERMINALS. THESE CEILINGS WILL LIFT AND
SCATTER TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR
MASS WILL ALSO CAUSE SCATTERED TO NUMEROUS SHOWERS AND STORMS TO
DEVELOP THIS AFTERNOON...AND THESE WILL LIKELY CONTINUE UNTIL A COLD
FRONT SWEEPS ACROSS CENTRAL NC FROM WEST TO EAST BETWEEN 04-06Z AT
TRIAD TERMINALS...TO 09-12Z AT EASTERN ONES. AREAS O FOG OR LOW
STRATUS WILL ALSO BE POSSIBLE AHEAD OF THE COLD FRONT...MOST LIKELY
AT KFAY AND KRWI BETWEEN 06-12Z.
VFR CONDITIONS WILL OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE
THROUGH THE HOLIDAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A
FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BSD
SHORT TERM...ELLIS
LONG TERM...MLM
AVIATION...MWS
CLIMATE...RAH
000
FXUS62 KRAH 230608
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
208 AM EDT THU MAY 23 2013
.SYNOPSIS...
A TROUGH ALOFT AND ACCOMPANYING PRE-FRONTAL SURFACE PRESSURE TROUGH
WILL MOVE INTO CENTRAL NC TODAY...FOLLOWED BY THE PASSAGE OF A COLD
FRONT TONIGHT. CANADIAN HIGH PRESSURE WILL THEN EXPAND ACROSS OUR
REGION THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 PM WEDNESDAY...
ANY SHOWERS AND THUNDERSTORMS FROM THIS AFTERNOON AND EVENING
ASSOCIATED WITH THE SEA BREEZE AND OUTFLOW ACROSS THE EASTERN
TWO-THIRDS OF THE AREA HAVE DISSIPATED WITH THE LOSS OF DAYTIME
HEATING AND RESULTANT STABILIZING BOUNDARY LAYER. CONVECTION THAT
FIRED ACROSS THE HIGHER TERRAIN TODAY... HAS GENERALLY STAYED TO THE
WEST OF THE REGION WITH A 15 TO 20 KT SOUTH-SOUTHWESTERLY MEAN
STEERING FLOW. HOWEVER... A WEST-NORTHWESTERLY OUTFLOW... GENERATED
FROM THESE CLUSTERS OF SHOWERS AND STORMS THAT ORIGINATED ALONG THE
HIGHER TERRAIN... HAS FINALLY ALLOWED FOR THE DEVELOPMENT OF SHOWERS
AND STORMS ACROSS OUR FAR NORTHWESTERN REACHES OF OUR CWA... ALONG
THE OUTFLOW. THINK THIS OUTFLOW SHOULD SUPPORT AT LEAST SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ACROSS OUR WESTERN PIEDMONT
THROUGH 06/07Z... GIVEN 500 TO 1000 J/KG OF SURFACE BASED CAPE.
THEREAFTER... EXPECT BOUNDARY LAYER COOLING SHOULD YIELD A TREND TO
ISOLATED SHOWERS AT BEST. ANY SIGNIFICANT S/W ENERGY ROTATING
THROUGH THE CYCLONIC FLOW ALOFT FROM THE APPROACHING MID LEVEL
TROUGH WELL TO THE WEST OF THE AREA... INVOF THE MS RIVER THIS
EVENING... IS EXPECTED TO PASS TO THE WEST AND NORTH OF THE REGION
THUS... PLAN TO TRIM POPS TO SLIGHT CHANCE BY EARLY THURSDAY MORNING
ACROSS THE ENTIRE CWA. THIS IS SUPPORTED BY THE LATEST HRRR.
HOWEVER... ITS WORTH NOTING THE LATEST HRRR DOES SHOW SOME SHOWERS
CURRENTLY OFF THE CAROLINA COAST MOVING ONSHORE OVERNIGHT ACROSS THE
COASTAL PLAIN. CURRENT HI-RES MODELS GENERALLY SHOW THIS PRECIP
REMAINING JUST TO THE EAST OF OUR AREA. THUS... WILL KEEP ONLY
SLIGHT CHANCE POPS ACROSS OUR EAST AS WELL. OVERNIGHT LOWS IN THE
MID TO UPPER 60S ARE STILL EXPECTED... WITH GENERALLY PATCHY FOG
(FOG... AT LOCATIONS THAT ARE PICKING UP DECENT SHOWERS/STORMS
ACROSS THE TRIAD NOW) AND WIDESPREAD LOW STATUS.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 PM WEDNESDAY...
A COLD FRONT WILL APPROACH CENTRAL NC FROM THE WEST ON FRIDAY. AS A
DEEP 500 MB TROUGH DIGS SOUTHWARD THROUGH THE OHIO VALLEY. AS FAR AS
TIMING IS CONCERNED...SHOWERS AND THUNDERSTORMS AHEAD OF FRONT WILL
BEGIN TO AFFECT THE TRIAD BY LATE THURSDAY MORNING AND CONTINUE TO
PROGRESS SLOWLY EASTWARD ACROSS THE CWA BY AFTERNOON/EVENING. SEVERE
POTENTIAL WITH THIS SYSTEM WILL BE GREATER THAN THE PAST COUPLE OF
DAYS BUT STILL LOOKS VERY LOW. EFFECTIVE SHEAR WILL BE ABOUT 20
KNOTS SUGGESTING MORE LINEAR THUNDERSTORMS. THIS IS SUPPORTED BY THE
STRAIGHT HODOGRAPHS SHOWN BY NAM FORECAST SOUNDINGS. MID LEVEL LAPSE
RATES WILL BE WEEK ALTHOUGH 1000 ML CAPE OF THE TALL AND SKINNY
VARIETY COULD BE REALIZED BY AFTERNOON. LATER IN THE EVENT DYNAMICS
IMPROVE AS A 30 KNOT 850MB APPROACHES THE NORTHWEST. IT IS UNCLEAR
AT THIS TIME WHETHER OR NOT CONVECTION WILL BE TOO FAR TO THE EAST
TO TAKE ADVANTAGE OF THE INCREASED SHEAR. STORMS LINGERING BACK
TOWARDS THE WEST MAY BE ABLE TO TAKE ADVANTAGE OF AN INCREASED AXIS
OF DCAPE EXPECTED TO MOVE THROUGH THE CWA JUST AFTER 00Z FRIDAY.
THEREFORE IF WE DO ENCOUNTER SEVERE WEATHER TOMORROW...IT WILL MOST
LIKELY BE DAMAGING WINDS AND NOT HAIL. FOR NOW SPC HAS KEPT THE
RALEIGH AREA OUT OF THE SLIGHT RISK AREA FOR TOMORROW. PRECIPITABLE
WATERS WILL BE SIMILAR TO TODAY NEAR 1.5 INCHES BUT QPF WITH FRONTAL
PASSAGE IS ONLY EXPECTED TO BE BETWEEN A QUARTER AND A HALF OF AN
INCH WITH LOCALLY HEAVIER AMOUNTS POSSIBLE IN THUNDERSTORMS.
LOCALIZED FLOODING COULD BE AN ISSUE...ESPECIALLY IN URBAN AREAS
UNDER SLOW MOVING OR TRAINING THUNDERSTORMS. CLOUD COVER SHOULD
OVERSPREAD THE AREA FAIRLY EARLY TOMORROW AND THUS WILL TREND
TOWARDS THE COOLER MET GUIDANCE WITH HIGH TEMPERATURES. UPPER 70S IN
THE NORTHWEST TO LOW 80S SOUTHEAST. AS THE LOWER ATMOSPHERE BEGINS
TO DRY OUT LOW TEMPERATURES IN THE TRIAD SHOULD DIP INTO THE UPPER
50S IN THE NORTHWEST FOR THE FIRST TIME IN SEVERAL DAYS BUT FURTHER
TO THE SOUTHEAST LOWS WILL REMAIN IN THE MIDDLE 60S AS THE FRONT IS
EXPECTED TO FULLY MOVE THROUGH THE EAST UNTIL CLOSER TO 6Z ON FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 310 PM WEDNESDAY...
FRIDAY THROUGH SATURDAY NIGHT...
A DEEP UPPER LEVEL TROUGH WILL SWING ACROSS CENTRAL NC FRIDAY AND
EXIT THE REGION FRIDAY NIGHT. MAY SEE A FEW INSTABILITY SHOWERS
WITH THE PASSAGE OF THIS SYSTEM HOWEVER MODEL RH CROSS SECTIONS
DEPICT THE AIR MASS DRYING OUT APPRECIABLY ABOVE 5000-8000FT BY
EARLY AFTERNOON. FOR NOW WILL LIMIT POPS TO SLIGHT CHANCE. OTHERWISE
BRISK NW FLOW WILL ADVECT COOLER MORE STABLE AIR INTO THE REGION.
SUSTAINED NW WINDS 10-15 MPH WITH GUSTS AROUND 25 MPH PROBABLE. THE
ARRIVAL OF THIS AIR MASS WILL RESULT IN COOLER CONDITIONS WITH
AFTERNOON MAX TEMPS IN THE LOWER 70S NORTH TO UPPER 70S FAR SE.
FRIDAY NIGHT...SKIES WILL CLEAR EARLY THOUGH A STEADY NW SFC WIND
WILL BE SLOW TO SUBSIDE. LOW LEVEL THICKNESSES CLUSTERING AROUND
1340M. HISTORICALLY...THIS SUGGEST MIN TEMPS NEAR 40-LOWER 40S.
FAVOR THE HIGH END OF THIS REGION DUE TO EXPECTED MIXING WELL INTO
THE NIGHT. MIN TEMPS 45-50.
SATURDAY INTO SATURDAY NIGHT...CANADIAN HIGH PRESSURE OVER THE LOWER
GREAT LAKES WILL BUILD/EXTEND INTO OUR REGION SATURDAY INTO SATURDAY
NIGHT. THIS WEATHER SYSTEM WILL RESULT IN A DRY WEATHER PATTERN WITH
BELOW NORMAL TEMPS. AFTERNOON THICKNESSES PROJECTED TO BE ABOUT 35M
BELOW NORMAL...SUPPORTIVE OF TEMPS CLOSE TO 10 DEGREES BELOW NORMAL.
ALLOWING FOR WARMTH FROM LATE MAY SUN...EXPECT AFTERNOON HIGH TEMPS
IN THE MID-UPPER 70S. MOS GUIDANCE LIKELY TRENDING TOWARD
CLIMATOLOGY BY SATURDAY NIGHT. WITH SFC RIDGE OVERHEAD AND CORE OF
LOW LEVEL DRY ACROSS THE REGION...TEMPS SHOULD COOL QUICKLY INT EH
EVENING THEN STABILIZE. MODEL RH CROSS SECTIONS HINT AT INCREASING
MID-HIGH LEVEL CLOUDS OVERNIGHT INTO EARLY SUNDAY. FIRST GLANCE
SUGGEST THAT CLOUD COVERAGE MAY INITIALLY BE THIN AND SPOTTY SO
COULD SEE DECENT NOCTURNAL COOLING. FAVOR MIN TEMPS A FEW DEGREES
COOLER THAN PREVIOUS FORECAST WITH MIN TEMPS IN THE MID-UPPER 40S.
SUNDAY INTO MONDAY...DEEP UPPER LEVEL LOW OVER NORTHERN NEW
ENGLAND-CANADIAN MARITIME PROVINCES WILL MAINTAIN A NW FLOW OVER THE
FORECAST AREA SUNDAY. WEAK PERTURBATIONS IN THIS FLOW ALOFT WORKING
WITH AVAILABLE MOISTURE WILL LIKELY CAUSE AN INCREASE IN MID-HIGH
LEVEL CLOUDINESS SUNDAY INTO SUNDAY NIGHT...MORE SO ACROSS OUR WEST
AND SOUTH SECTIONS AND LEAST IN THE NE. A MODIFYING AIR MASS WILL
LEAD TO SLIGHTLY WARMER CONDITIONS WITH AFTERNOON TEMPS IN THE
MID-UPPER 70S...AND AND MIN TEMPS IN THE MID 50S. 00Z ECMWF SUGGEST
THAT THERE MAY BE ENOUGH AMPLITUDE TO AN APPROACHING MID LEVEL
TROUGH TO WARRANT A SLIGHT-SMALL CHANCE POP ACROSS CENTRAL NC MONDAY
AFTERNOON-MONDAY EVENING.
TUESDAY INTO WEDNESDAY...AN AMPLIFYING MID-UPPER LEVEL RIDGE OVER
THE EASTERN HALF OF THE U.S. WILL PLACE CENTRAL NC BACK INTO A
SUMMER-LIKE PATTERN WITH A SFC HIGH ANCHORED OFFSHORE BUT EXTENDING
WESTWARD INTO THE SE U.S. THIS SUGGEST A RETURN TO WARM AND SLIGHTLY
HUMID CONDITIONS WITH AFTERNOON TEMPS IN THE LOW-MID 80S AND MIN
TEMPS 60-65. CONVECTION APPEARS TO BE DIURNALLY DRIVEN...ADDED BY A
SEABREEZE TO SE AND NW FLOW ALOFT SENDING CONVECTION OFF THE HIGHER
TERRAIN INTO THE WESTERN PIEDMONT. POPS NO HIGHER THAN SLIGHT
CHANCE-SMALL CHANCE AT THIS TIME...CONFINED TO THE AFTERNOON-EVENING
HOURS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 205 AM THURSDAY...
A LINE OF SHOWERS AND ISOLATED STORMS THAT EARLIER AFFECTED THE
TRIAD TERMINALS WILL CONTINUE TO MOVE SLOWLY EASTWARD AT AROUND 10
MPH...AFFECTING THE KRDU AREA BETWEEN 8-10Z. A GRADUAL
WEAKENING/DISSIPATING TREND SHOULD OCCUR AS THE AIR MASS CONTINUES
TO STABILIZE WITH NOCTURNAL COOLING...HOWEVER...SO CONFIDENCE OF THE
CONVECTION REACHING THE KFAY AND KRWI AREAS IS LOW. OTHERWISE...A
CONTINUED MOIST AIR MASS WILL PROMOTE A HIGH CHANCE OF LIFR-IFR
CEILINGS THIS MORNING...THOUGH WITH RELATIVE LOWEST CHANCES - AROUND
60 PERCENT - AT TRIAD TERMINALS. THESE CEILINGS WILL LIFT AND
SCATTER TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR
MASS WILL ALSO CAUSE SCATTERED TO NUMEROUS SHOWERS AND STORMS TO
DEVELOP THIS AFTERNOON...AND THESE WILL LIKELY CONTINUE UNTIL A COLD
FRONT SWEEPS ACROSS CENTRAL NC FROM WEST TO EAST BETWEEN 04-06Z AT
TRIAD TERMINALS...TO 09-12Z AT EASTERN ONES. AREAS O FOG OR LOW
STRATUS WILL ALSO BE POSSIBLE AHEAD OF THE COLD FRONT...MOST LIKELY
AT KFAY AND KRWI BETWEEN 06-12Z.
VFR CONDITIONS WILL OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE
THROUGH THE HOLIDAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A
FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BSD
SHORT TERM...ELLIS
LONG TERM...WSS
AVIATION...MWS
CLIMATE...RAH
000
FXUS62 KRAH 230216
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1013 PM EDT WED MAY 22 2013
.SYNOPSIS...
A MOIST SOUTHERLY WIND FLOW WILL PERSIST ACROSS CENTRAL NC THROUGH
THURSDAY. A COLD FRONT WILL CROSS THE REGION LATE THURSDAY AND
THURSDAY NIGHT. A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE
CAROLINAS FRIDAY AND LINGER OVERHEAD THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1010 PM WEDNESDAY...
ANY SHOWERS AND THUNDERSTORMS FROM THIS AFTERNOON AND EVENING
ASSOCIATED WITH THE SEA BREEZE AND OUTFLOW ACROSS THE EASTERN
TWO-THIRDS OF THE AREA HAVE DISSIPATED WITH THE LOSS OF DAYTIME
HEATING AND RESULTANT STABILIZING BOUNDARY LAYER. CONVECTION THAT
FIRED ACROSS THE HIGHER TERRAIN TODAY... HAS GENERALLY STAYED TO THE
WEST OF THE REGION WITH A 15 TO 20 KT SOUTH-SOUTHWESTERLY MEAN
STEERING FLOW. HOWEVER... A WEST-NORTHWESTERLY OUTFLOW... GENERATED
FROM THESE CLUSTERS OF SHOWERS AND STORMS THAT ORIGINATED ALONG THE
HIGHER TERRAIN... HAS FINALLY ALLOWED FOR THE DEVELOPMENT OF SHOWERS
AND STORMS ACROSS OUR FAR NORTHWESTERN REACHES OF OUR CWA... ALONG
THE OUTFLOW. THINK THIS OUTFLOW SHOULD SUPPORT AT LEAST SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ACROSS OUR WESTERN PIEDMONT
THROUGH 06/07Z... GIVEN 500 TO 1000 J/KG OF SURFACE BASED CAPE.
THEREAFTER... EXPECT BOUNDARY LAYER COOLING SHOULD YIELD A TREND TO
ISOLATED SHOWERS AT BEST. ANY SIGNIFICANT S/W ENERGY ROTATING
THROUGH THE CYCLONIC FLOW ALOFT FROM THE APPROACHING MID LEVEL
TROUGH WELL TO THE WEST OF THE AREA... INVOF THE MS RIVER THIS
EVENING... IS EXPECTED TO PASS TO THE WEST AND NORTH OF THE REGION
THUS... PLAN TO TRIM POPS TO SLIGHT CHANCE BY EARLY THURSDAY MORNING
ACROSS THE ENTIRE CWA. THIS IS SUPPORTED BY THE LATEST HRRR.
HOWEVER... ITS WORTH NOTING THE LATEST HRRR DOES SHOW SOME SHOWERS
CURRENTLY OFF THE CAROLINA COAST MOVING ONSHORE OVERNIGHT ACROSS THE
COASTAL PLAIN. CURRENT HI-RES MODELS GENERALLY SHOW THIS PRECIP
REMAINING JUST TO THE EAST OF OUR AREA. THUS... WILL KEEP ONLY
SLIGHT CHANCE POPS ACROSS OUR EAST AS WELL. OVERNIGHT LOWS IN THE
MID TO UPPER 60S ARE STILL EXPECTED... WITH GENERALLY PATCHY FOG
(FOG... AT LOCATIONS THAT ARE PICKING UP DECENT SHOWERS/STORMS
ACROSS THE TRIAD NOW) AND WIDESPREAD LOW STATUS.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 PM WEDNESDAY...
A COLD FRONT WILL APPROACH CENTRAL NC FROM THE WEST ON FRIDAY. AS A
DEEP 500 MB TROUGH DIGS SOUTHWARD THROUGH THE OHIO VALLEY. AS FAR AS
TIMING IS CONCERNED...SHOWERS AND THUNDERSTORMS AHEAD OF FRONT WILL
BEGIN TO AFFECT THE TRIAD BY LATE THURSDAY MORNING AND CONTINUE TO
PROGRESS SLOWLY EASTWARD ACROSS THE CWA BY AFTERNOON/EVENING. SEVERE
POTENTIAL WITH THIS SYSTEM WILL BE GREATER THAN THE PAST COUPLE OF
DAYS BUT STILL LOOKS VERY LOW. EFFECTIVE SHEAR WILL BE ABOUT 20
KNOTS SUGGESTING MORE LINEAR THUNDERSTORMS. THIS IS SUPPORTED BY THE
STRAIGHT HODOGRAPHS SHOWN BY NAM FORECAST SOUNDINGS. MID LEVEL LAPSE
RATES WILL BE WEEK ALTHOUGH 1000 ML CAPE OF THE TALL AND SKINNY
VARIETY COULD BE REALIZED BY AFTERNOON. LATER IN THE EVENT DYNAMICS
IMPROVE AS A 30 KNOT 850MB APPROACHES THE NORTHWEST. IT IS UNCLEAR
AT THIS TIME WHETHER OR NOT CONVECTION WILL BE TOO FAR TO THE EAST
TO TAKE ADVANTAGE OF THE INCREASED SHEAR. STORMS LINGERING BACK
TOWARDS THE WEST MAY BE ABLE TO TAKE ADVANTAGE OF AN INCREASED AXIS
OF DCAPE EXPECTED TO MOVE THROUGH THE CWA JUST AFTER 00Z FRIDAY.
THEREFORE IF WE DO ENCOUNTER SEVERE WEATHER TOMORROW...IT WILL MOST
LIKELY BE DAMAGING WINDS AND NOT HAIL. FOR NOW SPC HAS KEPT THE
RALEIGH AREA OUT OF THE SLIGHT RISK AREA FOR TOMORROW. PRECIPITABLE
WATERS WILL BE SIMILAR TO TODAY NEAR 1.5 INCHES BUT QPF WITH FRONTAL
PASSAGE IS ONLY EXPECTED TO BE BETWEEN A QUARTER AND A HALF OF AN
INCH WITH LOCALLY HEAVIER AMOUNTS POSSIBLE IN THUNDERSTORMS.
LOCALIZED FLOODING COULD BE AN ISSUE...ESPECIALLY IN URBAN AREAS
UNDER SLOW MOVING OR TRAINING THUNDERSTORMS. CLOUD COVER SHOULD
OVERSPREAD THE AREA FAIRLY EARLY TOMORROW AND THUS WILL TREND
TOWARDS THE COOLER MET GUIDANCE WITH HIGH TEMPERATURES. UPPER 70S IN
THE NORTHWEST TO LOW 80S SOUTHEAST. AS THE LOWER ATMOSPHERE BEGINS
TO DRY OUT LOW TEMPERATURES IN THE TRIAD SHOULD DIP INTO THE UPPER
50S IN THE NORTHWEST FOR THE FIRST TIME IN SEVERAL DAYS BUT FURTHER
TO THE SOUTHEAST LOWS WILL REMAIN IN THE MIDDLE 60S AS THE FRONT IS
EXPECTED TO FULLY MOVE THROUGH THE EAST UNTIL CLOSER TO 6Z ON FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 310 PM WEDNESDAY...
FRIDAY THROUGH SATURDAY NIGHT...
A DEEP UPPER LEVEL TROUGH WILL SWING ACROSS CENTRAL NC FRIDAY AND
EXIT THE REGION FRIDAY NIGHT. MAY SEE A FEW INSTABILITY SHOWERS
WITH THE PASSAGE OF THIS SYSTEM HOWEVER MODEL RH CROSS SECTIONS
DEPICT THE AIR MASS DRYING OUT APPRECIABLY ABOVE 5000-8000FT BY
EARLY AFTERNOON. FOR NOW WILL LIMIT POPS TO SLIGHT CHANCE. OTHERWISE
BRISK NW FLOW WILL ADVECT COOLER MORE STABLE AIR INTO THE REGION.
SUSTAINED NW WINDS 10-15 MPH WITH GUSTS AROUND 25 MPH PROBABLE. THE
ARRIVAL OF THIS AIR MASS WILL RESULT IN COOLER CONDITIONS WITH
AFTERNOON MAX TEMPS IN THE LOWER 70S NORTH TO UPPER 70S FAR SE.
FRIDAY NIGHT...SKIES WILL CLEAR EARLY THOUGH A STEADY NW SFC WIND
WILL BE SLOW TO SUBSIDE. LOW LEVEL THICKNESSES CLUSTERING AROUND
1340M. HISTORICALLY...THIS SUGGEST MIN TEMPS NEAR 40-LOWER 40S.
FAVOR THE HIGH END OF THIS REGION DUE TO EXPECTED MIXING WELL INTO
THE NIGHT. MIN TEMPS 45-50.
SATURDAY INTO SATURDAY NIGHT...CANADIAN HIGH PRESSURE OVER THE LOWER
GREAT LAKES WILL BUILD/EXTEND INTO OUR REGION SATURDAY INTO SATURDAY
NIGHT. THIS WEATHER SYSTEM WILL RESULT IN A DRY WEATHER PATTERN WITH
BELOW NORMAL TEMPS. AFTERNOON THICKNESSES PROJECTED TO BE ABOUT 35M
BELOW NORMAL...SUPPORTIVE OF TEMPS CLOSE TO 10 DEGREES BELOW NORMAL.
ALLOWING FOR WARMTH FROM LATE MAY SUN...EXPECT AFTERNOON HIGH TEMPS
IN THE MID-UPPER 70S. MOS GUIDANCE LIKELY TRENDING TOWARD
CLIMATOLOGY BY SATURDAY NIGHT. WITH SFC RIDGE OVERHEAD AND CORE OF
LOW LEVEL DRY ACROSS THE REGION...TEMPS SHOULD COOL QUICKLY INT EH
EVENING THEN STABILIZE. MODEL RH CROSS SECTIONS HINT AT INCREASING
MID-HIGH LEVEL CLOUDS OVERNIGHT INTO EARLY SUNDAY. FIRST GLANCE
SUGGEST THAT CLOUD COVERAGE MAY INITIALLY BE THIN AND SPOTTY SO
COULD SEE DECENT NOCTURNAL COOLING. FAVOR MIN TEMPS A FEW DEGREES
COOLER THAN PREVIOUS FORECAST WITH MIN TEMPS IN THE MID-UPPER 40S.
SUNDAY INTO MONDAY...DEEP UPPER LEVEL LOW OVER NORTHERN NEW
ENGLAND-CANADIAN MARITIME PROVINCES WILL MAINTAIN A NW FLOW OVER THE
FORECAST AREA SUNDAY. WEAK PERTURBATIONS IN THIS FLOW ALOFT WORKING
WITH AVAILABLE MOISTURE WILL LIKELY CAUSE AN INCREASE IN MID-HIGH
LEVEL CLOUDINESS SUNDAY INTO SUNDAY NIGHT...MORE SO ACROSS OUR WEST
AND SOUTH SECTIONS AND LEAST IN THE NE. A MODIFYING AIR MASS WILL
LEAD TO SLIGHTLY WARMER CONDITIONS WITH AFTERNOON TEMPS IN THE
MID-UPPER 70S...AND AND MIN TEMPS IN THE MID 50S. 00Z ECMWF SUGGEST
THAT THERE MAY BE ENOUGH AMPLITUDE TO AN APPROACHING MID LEVEL
TROUGH TO WARRANT A SLIGHT-SMALL CHANCE POP ACROSS CENTRAL NC MONDAY
AFTERNOON-MONDAY EVENING.
TUESDAY INTO WEDNESDAY...AN AMPLIFYING MID-UPPER LEVEL RIDGE OVER
THE EASTERN HALF OF THE U.S. WILL PLACE CENTRAL NC BACK INTO A
SUMMER-LIKE PATTERN WITH A SFC HIGH ANCHORED OFFSHORE BUT EXTENDING
WESTWARD INTO THE SE U.S. THIS SUGGEST A RETURN TO WARM AND SLIGHTLY
HUMID CONDITIONS WITH AFTERNOON TEMPS IN THE LOW-MID 80S AND MIN
TEMPS 60-65. CONVECTION APPEARS TO BE DIURNALLY DRIVEN...ADDED BY A
SEABREEZE TO SE AND NW FLOW ALOFT SENDING CONVECTION OFF THE HIGHER
TERRAIN INTO THE WESTERN PIEDMONT. POPS NO HIGHER THAN SLIGHT
CHANCE-SMALL CHANCE AT THIS TIME...CONFINED TO THE AFTERNOON-EVENING
HOURS.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 750 PM WEDNESDAY...
SEABREEZE AND OUTFLOW GENERATED SHOWERS HAVE MOSTLY DISSIPATED IN
THE LAST HOUR...WITH MORE ROBUST CONVECTION JUST TO THE WEST OF KINT
CONTINUING TO MOVE SOUTHWEST TO NORTHEAST. THERE IS NOT MUCH
EVIDENCE ON RADAR OF THESE CELLS MOVING EAST MAKING MUCH PROGRESS
EAST TOWARD KINT...SO WILL KEEP VCSH IN THE KINT TAF THROUGH 03Z.
THE MORE PROGRESSIVE AREA OF CONVECTION AND OUTFLOW IS STILL WEST OF
KHKY. THE OVERALL WEAKENING TREND OF CONVECTION IS EXPECTED TO
CONTINUE THIS EVENING...WITH IFR/MVFR STRATUS EXPECTED TO DEVELOP
AFTER MIDNIGHT.
THE THREAT OF SCATTERED CONVECTION WILL CONTINUE ON THURSDAY AHEAD
OF AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT OVER THE MIDWEST
STATES. MODEL GUIDANCE SUGGESTS SHOWERS MAY BE POSSIBLE AS EARLY AS
12Z NEAR KGSO/KINT...WITH MORE WIDESPREAD SHOWERS AND STORMS MORE
LIKELY THURSDAY AFTERNOON AS THE TROUGH AND COLD FRONT APPROACH FROM
THE WEST. CEILINGS WILL BREAK BY MIDDAY THURSDAY...WITH CLOUD BASED
EXPECTED TO LIFT TO AROUND 3500-4000 FT THURSDAY AFTERNOON.
OUTLOOK...
A COLD FRONT MOVING THROUGH THE AREA LATE THURSDAY AND EARLY FRIDAY
WILL CONTINUE THE THREAT OF ADVERSE AVIATION CONDITIONS. VFR
CONDITIONS ARE EXPECTED TO RETURN DURING THE DAY FRIDAY AND PREVAIL
THROUGH THE WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A
FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BSD
SHORT TERM...ELLIS
LONG TERM...WSS
AVIATION...SMITH
CLIMATE...RAH
000
FXUS62 KRAH 222355
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
750 PM EDT WED MAY 22 2013
.SYNOPSIS...
A MOIST SOUTHERLY WIND FLOW WILL PERSIST ACROSS CENTRAL NC THROUGH
THURSDAY. A COLD FRONT WILL CROSS THE REGION LATE THURSDAY AND
THURSDAY NIGHT. A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE
CAROLINAS FRIDAY AND LINGER OVERHEAD THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM WEDNESDAY...
CENTRAL NC CONTINUES TO SIT BETWEEN SURFACE HIGH PRESSURE OFF THE
COAST AND AN ADVANCING FRONTAL SYSTEM TO THE WEST. UPPER LEVEL
RIDGING OVER THE AREA AND DECREASED MOISTURE HAS LED TO A QUIETER
DAY TODAY AS FAR AS CONVECTION IS CONCERNED. AS OF 18Z THE CURRENT
RADAR SHOWS AN AXIS OF CONVECTION POPPING UP ALONG THE SEA BREEZE
FRONT WHICH IS CURRENTLY STILL EAST OF THE I-95 CORRIDOR. THIS WILL
SLOWLY ADVECT NORTHEASTWARD BUT IS NOT EXPECTED TO PROPAGATE TOO FAR
INLAND THIS AFTERNOON. OTHER WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE OVER THE NEXT COUPLE OF HOURS. SEVERE
PARAMETERS REMAIN LOW AND SEVERE WEATHER IS NOT EXPECTED THIS
AFTERNOON. WINDS REMAIN OUT OF THE SOUTH SOUTHWEST NEAR 10 KNOTS
GUSTING TO 15-20 KNOTS. HIGHS WILL TOP OUT IN THE MIDDLE 80S THIS
AFTERNOON.
FOR TONIGHT SHOWERS AND THUNDERSTORMS WILL END AFTER 00Z AND LOW
STRATUS IS ONCE AGAIN EXPECTED ACROSS THE CWA AS DEWPOINTS REMAIN
ELEVATED INTO THE MID 60S. CEILINGS SHOULD BE AROUND 1000 FEET
OVERNIGHT. LOW TEMPERATURES ARE EXPECTED TO BE IN THE LOW 60S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 PM WEDNESDAY...
A COLD FRONT WILL APPROACH CENTRAL NC FROM THE WEST ON FRIDAY. AS A
DEEP 500 MB TROUGH DIGS SOUTHWARD THROUGH THE OHIO VALLEY. AS FAR AS
TIMING IS CONCERNED...SHOWERS AND THUNDERSTORMS AHEAD OF FRONT WILL
BEGIN TO AFFECT THE TRIAD BY LATE THURSDAY MORNING AND CONTINUE TO
PROGRESS SLOWLY EASTWARD ACROSS THE CWA BY AFTERNOON/EVENING. SEVERE
POTENTIAL WITH THIS SYSTEM WILL BE GREATER THAN THE PAST COUPLE OF
DAYS BUT STILL LOOKS VERY LOW. EFFECTIVE SHEAR WILL BE ABOUT 20
KNOTS SUGGESTING MORE LINEAR THUNDERSTORMS. THIS IS SUPPORTED BY THE
STRAIGHT HODOGRAPHS SHOWN BY NAM FORECAST SOUNDINGS. MID LEVEL LAPSE
RATES WILL BE WEEK ALTHOUGH 1000 ML CAPE OF THE TALL AND SKINNY
VARIETY COULD BE REALIZED BY AFTERNOON. LATER IN THE EVENT DYNAMICS
IMPROVE AS A 30 KNOT 850MB APPROACHES THE NORTHWEST. IT IS UNCLEAR
AT THIS TIME WHETHER OR NOT CONVECTION WILL BE TOO FAR TO THE EAST
TO TAKE ADVANTAGE OF THE INCREASED SHEAR. STORMS LINGERING BACK
TOWARDS THE WEST MAY BE ABLE TO TAKE ADVANTAGE OF AN INCREASED AXIS
OF DCAPE EXPECTED TO MOVE THROUGH THE CWA JUST AFTER 00Z FRIDAY.
THEREFORE IF WE DO ENCOUNTER SEVERE WEATHER TOMORROW...IT WILL MOST
LIKELY BE DAMAGING WINDS AND NOT HAIL. FOR NOW SPC HAS KEPT THE
RALEIGH AREA OUT OF THE SLIGHT RISK AREA FOR TOMORROW. PRECIPITABLE
WATERS WILL BE SIMILAR TO TODAY NEAR 1.5 INCHES BUT QPF WITH FRONTAL
PASSAGE IS ONLY EXPECTED TO BE BETWEEN A QUARTER AND A HALF OF AN
INCH WITH LOCALLY HEAVIER AMOUNTS POSSIBLE IN THUNDERSTORMS.
LOCALIZED FLOODING COULD BE AN ISSUE...ESPECIALLY IN URBAN AREAS
UNDER SLOW MOVING OR TRAINING THUNDERSTORMS. CLOUD COVER SHOULD
OVERSPREAD THE AREA FAIRLY EARLY TOMORROW AND THUS WILL TREND
TOWARDS THE COOLER MET GUIDANCE WITH HIGH TEMPERATURES. UPPER 70S IN
THE NORTHWEST TO LOW 80S SOUTHEAST. AS THE LOWER ATMOSPHERE BEGINS
TO DRY OUT LOW TEMPERATURES IN THE TRIAD SHOULD DIP INTO THE UPPER
50S IN THE NORTHWEST FOR THE FIRST TIME IN SEVERAL DAYS BUT FURTHER
TO THE SOUTHEAST LOWS WILL REMAIN IN THE MIDDLE 60S AS THE FRONT IS
EXPECTED TO FULLY MOVE THROUGH THE EAST UNTIL CLOSER TO 6Z ON FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 310 PM WEDNESDAY...
FRIDAY THROUGH SATURDAY NIGHT...
A DEEP UPPER LEVEL TROUGH WILL SWING ACROSS CENTRAL NC FRIDAY AND
EXIT THE REGION FRIDAY NIGHT. MAY SEE A FEW INSTABILITY SHOWERS
WITH THE PASSAGE OF THIS SYSTEM HOWEVER MODEL RH CROSS SECTIONS
DEPICT THE AIR MASS DRYING OUT APPRECIABLY ABOVE 5000-8000FT BY
EARLY AFTERNOON. FOR NOW WILL LIMIT POPS TO SLIGHT CHANCE. OTHERWISE
BRISK NW FLOW WILL ADVECT COOLER MORE STABLE AIR INTO THE REGION.
SUSTAINED NW WINDS 10-15 MPH WITH GUSTS AROUND 25 MPH PROBABLE. THE
ARRIVAL OF THIS AIR MASS WILL RESULT IN COOLER CONDITIONS WITH
AFTERNOON MAX TEMPS IN THE LOWER 70S NORTH TO UPPER 70S FAR SE.
FRIDAY NIGHT...SKIES WILL CLEAR EARLY THOUGH A STEADY NW SFC WIND
WILL BE SLOW TO SUBSIDE. LOW LEVEL THICKNESSES CLUSTERING AROUND
1340M. HISTORICALLY...THIS SUGGEST MIN TEMPS NEAR 40-LOWER 40S.
FAVOR THE HIGH END OF THIS REGION DUE TO EXPECTED MIXING WELL INTO
THE NIGHT. MIN TEMPS 45-50.
SATURDAY INTO SATURDAY NIGHT...CANADIAN HIGH PRESSURE OVER THE LOWER
GREAT LAKES WILL BUILD/EXTEND INTO OUR REGION SATURDAY INTO SATURDAY
NIGHT. THIS WEATHER SYSTEM WILL RESULT IN A DRY WEATHER PATTERN WITH
BELOW NORMAL TEMPS. AFTERNOON THICKNESSES PROJECTED TO BE ABOUT 35M
BELOW NORMAL...SUPPORTIVE OF TEMPS CLOSE TO 10 DEGREES BELOW NORMAL.
ALLOWING FOR WARMTH FROM LATE MAY SUN...EXPECT AFTERNOON HIGH TEMPS
IN THE MID-UPPER 70S. MOS GUIDANCE LIKELY TRENDING TOWARD
CLIMATOLOGY BY SATURDAY NIGHT. WITH SFC RIDGE OVERHEAD AND CORE OF
LOW LEVEL DRY ACROSS THE REGION...TEMPS SHOULD COOL QUICKLY INT EH
EVENING THEN STABILIZE. MODEL RH CROSS SECTIONS HINT AT INCREASING
MID-HIGH LEVEL CLOUDS OVERNIGHT INTO EARLY SUNDAY. FIRST GLANCE
SUGGEST THAT CLOUD COVERAGE MAY INITIALLY BE THIN AND SPOTTY SO
COULD SEE DECENT NOCTURNAL COOLING. FAVOR MIN TEMPS A FEW DEGREES
COOLER THAN PREVIOUS FORECAST WITH MIN TEMPS IN THE MID-UPPER 40S.
SUNDAY INTO MONDAY...DEEP UPPER LEVEL LOW OVER NORTHERN NEW
ENGLAND-CANADIAN MARITIME PROVINCES WILL MAINTAIN A NW FLOW OVER THE
FORECAST AREA SUNDAY. WEAK PERTURBATIONS IN THIS FLOW ALOFT WORKING
WITH AVAILABLE MOISTURE WILL LIKELY CAUSE AN INCREASE IN MID-HIGH
LEVEL CLOUDINESS SUNDAY INTO SUNDAY NIGHT...MORE SO ACROSS OUR WEST
AND SOUTH SECTIONS AND LEAST IN THE NE. A MODIFYING AIR MASS WILL
LEAD TO SLIGHTLY WARMER CONDITIONS WITH AFTERNOON TEMPS IN THE
MID-UPPER 70S...AND AND MIN TEMPS IN THE MID 50S. 00Z ECMWF SUGGEST
THAT THERE MAY BE ENOUGH AMPLITUDE TO AN APPROACHING MID LEVEL
TROUGH TO WARRANT A SLIGHT-SMALL CHANCE POP ACROSS CENTRAL NC MONDAY
AFTERNOON-MONDAY EVENING.
TUESDAY INTO WEDNESDAY...AN AMPLIFYING MID-UPPER LEVEL RIDGE OVER
THE EASTERN HALF OF THE U.S. WILL PLACE CENTRAL NC BACK INTO A
SUMMER-LIKE PATTERN WITH A SFC HIGH ANCHORED OFFSHORE BUT EXTENDING
WESTWARD INTO THE SE U.S. THIS SUGGEST A RETURN TO WARM AND SLIGHTLY
HUMID CONDITIONS WITH AFTERNOON TEMPS IN THE LOW-MID 80S AND MIN
TEMPS 60-65. CONVECTION APPEARS TO BE DIURNALLY DRIVEN...ADDED BY A
SEABREEZE TO SE AND NW FLOW ALOFT SENDING CONVECTION OFF THE HIGHER
TERRAIN INTO THE WESTERN PIEDMONT. POPS NO HIGHER THAN SLIGHT
CHANCE-SMALL CHANCE AT THIS TIME...CONFINED TO THE AFTERNOON-EVENING
HOURS.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 750 PM WEDNESDAY...
SEABREEZE AND OUTFLOW GENERATED SHOWERS HAVE MOSTLY DISSIPATED IN
THE LAST HOUR...WITH MORE ROBUST CONVECTION JUST TO THE WEST OF KINT
CONTINUING TO MOVE SOUTHWEST TO NORTHEAST. THERE IS NOT MUCH
EVIDENCE ON RADAR OF THESE CELLS MOVING EAST MAKING MUCH PROGRESS
EAST TOWARD KINT...SO WILL KEEP VCSH IN THE KINT TAF THROUGH 03Z.
THE MORE PROGRESSIVE AREA OF CONVECTION AND OUTFLOW IS STILL WEST OF
KHKY. THE OVERALL WEAKENING TREND OF CONVECTION IS EXPECTED TO
CONTINUE THIS EVENING...WITH IFR/MVFR STRATUS EXPECTED TO DEVELOP
AFTER MIDNIGHT.
THE THREAT OF SCATTERED CONVECTION WILL CONTINUE ON THURSDAY AHEAD
OF AN UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT OVER THE MIDWEST
STATES. MODEL GUIDANCE SUGGESTS SHOWERS MAY BE POSSIBLE AS EARLY AS
12Z NEAR KGSO/KINT...WITH MORE WIDESPREAD SHOWERS AND STORMS MORE
LIKELY THURSDAY AFTERNOON AS THE TROUGH AND COLD FRONT APPROACH FROM
THE WEST. CEILINGS WILL BREAK BY MIDDAY THURSDAY...WITH CLOUD BASED
EXPECTED TO LIFT TO AROUND 3500-4000 FT THURSDAY AFTERNOON.
OUTLOOK...
A COLD FRONT MOVING THROUGH THE AREA LATE THURSDAY AND EARLY FRIDAY
WILL CONTINUE THE THREAT OF ADVERSE AVIATION CONDITIONS. VFR
CONDITIONS ARE EXPECTED TO RETURN DURING THE DAY FRIDAY AND PREVAIL
THROUGH THE WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A
FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...ELLIS
SHORT TERM...ELLIS
LONG TERM...WSS
AVIATION...SMITH
CLIMATE...RAH
000
FXUS62 KRAH 221912
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
311 PM EDT WED MAY 22 2013
.SYNOPSIS...
A MOIST SOUTHERLY WIND FLOW WILL PERSIST ACROSS CENTRAL NC THROUGH
THURSDAY. A COLD FRONT WILL CROSS THE REGION LATE THURSDAY AND
THURSDAY NIGHT. A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE
CAROLINAS FRIDAY AND LINGER OVERHEAD THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM WEDNESDAY...
CENTRAL NC CONTINUES TO SIT BETWEEN SURFACE HIGH PRESSURE OFF THE
COAST AND AN ADVANCING FRONTAL SYSTEM TO THE WEST. UPPER LEVEL
RIDGING OVER THE AREA AND DECREASED MOISTURE HAS LED TO A QUIETER
DAY TODAY AS FAR AS CONVECTION IS CONCERNED. AS OF 18Z THE CURRENT
RADAR SHOWS AN AXIS OF CONVECTION POPPING UP ALONG THE SEA BREEZE
FRONT WHICH IS CURRENTLY STILL EAST OF THE I-95 CORRIDOR. THIS WILL
SLOWLY ADVECT NORTHEASTWARD BUT IS NOT EXPECTED TO PROPAGATE TOO FAR
INLAND THIS AFTERNOON. OTHER WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE OVER THE NEXT COUPLE OF HOURS. SEVERE
PARAMETERS REMAIN LOW AND SEVERE WEATHER IS NOT EXPECTED THIS
AFTERNOON. WINDS REMAIN OUT OF THE SOUTH SOUTHWEST NEAR 10 KNOTS
GUSTING TO 15-20 KNOTS. HIGHS WILL TOP OUT IN THE MIDDLE 80S THIS
AFTERNOON.
FOR TONIGHT SHOWERS AND THUNDERSTORMS WILL END AFTER 00Z AND LOW
STRATUS IS ONCE AGAIN EXPECTED ACROSS THE CWA AS DEWPOINTS REMAIN
ELEVATED INTO THE MID 60S. CEILINGS SHOULD BE AROUND 1000 FEET
OVERNIGHT. LOW TEMPERATURES ARE EXPECTED TO BE IN THE LOW 60S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 300 PM WEDNESDAY...
A COLD FRONT WILL APPROACH CENTRAL NC FROM THE WEST ON FRIDAY. AS A
DEEP 500 MB TROUGH DIGS SOUTHWARD THROUGH THE OHIO VALLEY. AS FAR AS
TIMING IS CONCERNED...SHOWERS AND THUNDERSTORMS AHEAD OF FRONT WILL
BEGIN TO AFFECT THE TRIAD BY LATE THURSDAY MORNING AND CONTINUE TO
PROGRESS SLOWLY EASTWARD ACROSS THE CWA BY AFTERNOON/EVENING. SEVERE
POTENTIAL WITH THIS SYSTEM WILL BE GREATER THAN THE PAST COUPLE OF
DAYS BUT STILL LOOKS VERY LOW. EFFECTIVE SHEAR WILL BE ABOUT 20
KNOTS SUGGESTING MORE LINEAR THUNDERSTORMS. THIS IS SUPPORTED BY THE
STRAIGHT HODOGRAPHS SHOWN BY NAM FORECAST SOUNDINGS. MID LEVEL LAPSE
RATES WILL BE WEEK ALTHOUGH 1000 ML CAPE OF THE TALL AND SKINNY
VARIETY COULD BE REALIZED BY AFTERNOON. LATER IN THE EVENT DYNAMICS
IMPROVE AS A 30 KNOT 850MB APPROACHES THE NORTHWEST. IT IS UNCLEAR
AT THIS TIME WHETHER OR NOT CONVECTION WILL BE TOO FAR TO THE EAST
TO TAKE ADVANTAGE OF THE INCREASED SHEAR. STORMS LINGERING BACK
TOWARDS THE WEST MAY BE ABLE TO TAKE ADVANTAGE OF AN INCREASED AXIS
OF DCAPE EXPECTED TO MOVE THROUGH THE CWA JUST AFTER 00Z FRIDAY.
THEREFORE IF WE DO ENCOUNTER SEVERE WEATHER TOMORROW...IT WILL MOST
LIKELY BE DAMAGING WINDS AND NOT HAIL. FOR NOW SPC HAS KEPT THE
RALEIGH AREA OUT OF THE SLIGHT RISK AREA FOR TOMORROW. PRECIPITABLE
WATERS WILL BE SIMILAR TO TODAY NEAR 1.5 INCHES BUT QPF WITH FRONTAL
PASSAGE IS ONLY EXPECTED TO BE BETWEEN A QUARTER AND A HALF OF AN
INCH WITH LOCALLY HEAVIER AMOUNTS POSSIBLE IN THUNDERSTORMS.
LOCALIZED FLOODING COULD BE AN ISSUE...ESPECIALLY IN URBAN AREAS
UNDER SLOW MOVING OR TRAINING THUNDERSTORMS. CLOUD COVER SHOULD
OVERSPREAD THE AREA FAIRLY EARLY TOMORROW AND THUS WILL TREND
TOWARDS THE COOLER MET GUIDANCE WITH HIGH TEMPERATURES. UPPER 70S IN
THE NORTHWEST TO LOW 80S SOUTHEAST. AS THE LOWER ATMOSPHERE BEGINS
TO DRY OUT LOW TEMPERATURES IN THE TRIAD SHOULD DIP INTO THE UPPER
50S IN THE NORTHWEST FOR THE FIRST TIME IN SEVERAL DAYS BUT FURTHER
TO THE SOUTHEAST LOWS WILL REMAIN IN THE MIDDLE 60S AS THE FRONT IS
EXPECTED TO FULLY MOVE THROUGH THE EAST UNTIL CLOSER TO 6Z ON FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 310 PM WEDNESDAY...
FRIDAY THROUGH SATURDAY NIGHT...
A DEEP UPPER LEVEL TROUGH WILL SWING ACROSS CENTRAL NC FRIDAY AND
EXIT THE REGION FRIDAY NIGHT. MAY SEE A FEW INSTABILITY SHOWERS
WITH THE PASSAGE OF THIS SYSTEM HOWEVER MODEL RH CROSS SECTIONS
DEPICT THE AIR MASS DRYING OUT APPRECIABLY ABOVE 5000-8000FT BY
EARLY AFTERNOON. FOR NOW WILL LIMIT POPS TO SLIGHT CHANCE. OTHERWISE
BRISK NW FLOW WILL ADVECT COOLER MORE STABLE AIR INTO THE REGION.
SUSTAINED NW WINDS 10-15 MPH WITH GUSTS AROUND 25 MPH PROBABLE. THE
ARRIVAL OF THIS AIR MASS WILL RESULT IN COOLER CONDITIONS WITH
AFTERNOON MAX TEMPS IN THE LOWER 70S NORTH TO UPPER 70S FAR SE.
FRIDAY NIGHT...SKIES WILL CLEAR EARLY THOUGH A STEADY NW SFC WIND
WILL BE SLOW TO SUBSIDE. LOW LEVEL THICKNESSES CLUSTERING AROUND
1340M. HISTORICALLY...THIS SUGGEST MIN TEMPS NEAR 40-LOWER 40S.
FAVOR THE HIGH END OF THIS REGION DUE TO EXPECTED MIXING WELL INTO
THE NIGHT. MIN TEMPS 45-50.
SATURDAY INTO SATURDAY NIGHT...CANADIAN HIGH PRESSURE OVER THE LOWER
GREAT LAKES WILL BUILD/EXTEND INTO OUR REGION SATURDAY INTO SATURDAY
NIGHT. THIS WEATHER SYSTEM WILL RESULT IN A DRY WEATHER PATTERN WITH
BELOW NORMAL TEMPS. AFTERNOON THICKNESSES PROJECTED TO BE ABOUT 35M
BELOW NORMAL...SUPPORTIVE OF TEMPS CLOSE TO 10 DEGREES BELOW NORMAL.
ALLOWING FOR WARMTH FROM LATE MAY SUN...EXPECT AFTERNOON HIGH TEMPS
IN THE MID-UPPER 70S. MOS GUIDANCE LIKELY TRENDING TOWARD
CLIMATOLOGY BY SATURDAY NIGHT. WITH SFC RIDGE OVERHEAD AND CORE OF
LOW LEVEL DRY ACROSS THE REGION...TEMPS SHOULD COOL QUICKLY INT EH
EVENING THEN STABILIZE. MODEL RH CROSS SECTIONS HINT AT INCREASING
MID-HIGH LEVEL CLOUDS OVERNIGHT INTO EARLY SUNDAY. FIRST GLANCE
SUGGEST THAT CLOUD COVERAGE MAY INITIALLY BE THIN AND SPOTTY SO
COULD SEE DECENT NOCTURNAL COOLING. FAVOR MIN TEMPS A FEW DEGREES
COOLER THAN PREVIOUS FORECAST WITH MIN TEMPS IN THE MID-UPPER 40S.
SUNDAY INTO MONDAY...DEEP UPPER LEVEL LOW OVER NORTHERN NEW
ENGLAND-CANADIAN MARITIME PROVINCES WILL MAINTAIN A NW FLOW OVER THE
FORECAST AREA SUNDAY. WEAK PERTURBATIONS IN THIS FLOW ALOFT WORKING
WITH AVAILABLE MOISTURE WILL LIKELY CAUSE AN INCREASE IN MID-HIGH
LEVEL CLOUDINESS SUNDAY INTO SUNDAY NIGHT...MORE SO ACROSS OUR WEST
AND SOUTH SECTIONS AND LEAST IN THE NE. A MODIFYING AIR MASS WILL
LEAD TO SLIGHTLY WARMER CONDITIONS WITH AFTERNOON TEMPS IN THE
MID-UPPER 70S...AND AND MIN TEMPS IN THE MID 50S. 00Z ECMWF SUGGEST
THAT THERE MAY BE ENOUGH AMPLITUDE TO AN APPROACHING MID LEVEL
TROUGH TO WARRANT A SLIGHT-SMALL CHANCE POP ACROSS CENTRAL NC MONDAY
AFTERNOON-MONDAY EVENING.
TUESDAY INTO WEDNESDAY...AN AMPLIFYING MID-UPPER LEVEL RIDGE OVER
THE EASTERN HALF OF THE U.S. WILL PLACE CENTRAL NC BACK INTO A
SUMMER-LIKE PATTERN WITH A SFC HIGH ANCHORED OFFSHORE BUT EXTENDING
WESTWARD INTO THE SE U.S. THIS SUGGEST A RETURN TO WARM AND SLIGHTLY
HUMID CONDITIONS WITH AFTERNOON TEMPS IN THE LOW-MID 80S AND MIN
TEMPS 60-65. CONVECTION APPEARS TO BE DIURNALLY DRIVEN...ADDED BY A
SEABREEZE TO SE AND NW FLOW ALOFT SENDING CONVECTION OFF THE HIGHER
TERRAIN INTO THE WESTERN PIEDMONT. POPS NO HIGHER THAN SLIGHT
CHANCE-SMALL CHANCE AT THIS TIME...CONFINED TO THE AFTERNOON-EVENING
HOURS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 120 PM WEDNESDAY...
24 HOUR TAF PERIOD: AS OF 17Z MOST SITES ACROSS CENTRAL NORTH
CAROLINA WERE REPORTING VFR CONDITIONS WITH SOUTH SOUTHWESTERLY
WINDS 5-10 KNOTS GUSTING TO 15 KNOTS. EXPECT GUSTS TO CONTINUE
THROUGH SUNSET. AS FAR AS PRECIPITATION GOES THIS AFTERNOON...MOST
CONVECTION ON THE RADAR AT THIS TIME IS ASSOCIATED WITH THE SEA
BREEZE. AS HEATING CONTINUES AND OTHER BOUNDARIES FORM BASED ON
BREAKS IN THE CLOUDS...EXPECT FURTHER DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS THIS AFTERNOON. EASTERN SITES SUCH AS KRWI AND KFAY
WILL BE THE MOST LIKELY TO SEE STORMS THIS AFTERNOON. SUB-VFR
CONDITIONS WILL AGAIN BE POSSIBLE TONIGHT MAINLY AFTER 6Z IN THE
FORM OF LOW STRATUS WITH BASES AROUND 1000 FT. IT IS POSSIBLE THAT
WE WILL MAINTAIN MVFR CEILINGS THROUGH THE END OF THE TAF PERIOD.
FOR NOW HAVE CEILINGS BREAKING BETWEEN 14-16Z FROM WEST TO EAST BUT
HOVERING NEAR 3500 FT. AS FRONT APPROACHES THE THREAT FOR SHOWERS
AND THUNDERSTORMS WILL INCREASE GOING INTO THURSDAY AFTERNOON. WINDS
THURSDAY AFTERNOON WILL REMAIN LARGELY SOUTHWESTERLY NEAR 10 KNOTS
GUSTING TO 15-20 KTS.
LONG TERM: ADVERSE AVIATION CONDITIONS ARE EXPECTED TO PREVAIL
THROUGH EARLY FRIDAY MORNING AS THE FRONTAL SYSTEM MOVES THROUGH THE
AREA. FRIDAY WILL SEE A PROLONGED RETURN TO VFR CONDITIONS THROUGH
MONDAY MAKING CONDITIONS VERY FAVORABLE FOR GENERAL AVIATION THROUGH
THE EXTENDED MEMORIAL DAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A
FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...ELLIS
SHORT TERM...ELLIS
LONG TERM...WSS
AVIATION...ELLIS
CLIMATE...RAH
000
FXUS62 KRAH 221910
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
310 PM EDT WED MAY 22 2013
.SYNOPSIS...
A MOIST SOUTHERLY WIND FLOW WILL PERSIST ACROSS CENTRAL NC THROUGH
THURSDAY. A COLD FRONT WILL CROSS THE REGION LATE THURSDAY AND
THURSDAY NIGHT. A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE
CAROLINAS FRIDAY AND LINGER OVERHEAD THROUGH THE HOLIDAY WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM WEDNESDAY...
QUIETER DAY TODAY AS CENTRAL NC SITS IN BETWEEN A SHORTWAVE SYSTEM
JUST OFF THE COAST AND A LARGER FRONTAL SYSTEM CURRENTLY STRETCHING
ACROSS THE MISSISSIPPI VALLEY THAT WILL CONTINUE TO PUSH EASTWARD
TODAY WITH THE PARENT LOW MOVING TOWARDS THE SOUTHERN GREAT LAKES.
FOR CENTRAL NC THE BIGGEST DIFFERENCE BETWEEN TODAY AND PREVIOUS
DAYS IS THE WEAKENING OF THE SHORTWAVE TROUGH AND THE PRESENCE OF
HIGH PRESSURE AT THE UPPER LEVELS OF THE ATMOSPHERE. IN ADDITION
PRECIPITABLE WATER VALUES HAVE RELAXED SOMEWHAT...NEAR 1.5 INCHES
WITH HIGHER VALUES SOUTH AND EAST AND DRIER CONDITIONS ACROSS THE
NORTHWESTERN PIEDMONT. CURRENT MVFR CEILINGS WILL GRADUALLY LIFT OUT
AND SET THE STAGE AGAIN FOR CUMULIFORM DEVELOPMENT LEADING TO
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. COVERAGE OF STORMS SHOULD
BE LESS THAN PREVIOUS DAYS AND SURFACE BOUNDARIES WILL ONCE AGAIN BE
THE CATALYST. SEVERE PARAMETERS WILL ONCE AGAIN BE VERY WEAK
OUTSIDE OF THE INSTABILITY WITH SHEAR ONLY AT 10 KNOTS OR SO AND
WEAK LAPSE RATES NEAR 5.5 DEG/KM. ML CAPE VALUES ONLY PREDICTED TO
BE ABOUT 800 J/KG OR SO. THEREFORE NOT EXPECTING ANY SEVERE WX THIS
AFTERNOON BUT POP UP SHOWERS AND THUNDERSTORMS WILL STILL BE
POSSIBLE...ESPECIALLY NEAR SURFACE BOUNDARIES. HIGH TEMPERATURES
TODAY SHOULD BENEFIT FROM BETTER INSOLATION AFTER MVFR CEILINGS BURN
OFF. EXPECT MIDDLE 80S ACROSS THE CWA TODAY. THERE IS THE POTENTIAL
FOR MORE LOW STRATUS TONIGHT AFTER SUNSET WITH CEILINGS CLOSER TO
2000 FEET. LOWS IN THE MIDDLE 60S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 308 AM WEDNESDAY...
COLD FRONT WILL CROSS THE AREA... ENTERING THE STATE FROM THE WEST
THURSDAY EVENING... AND WILL REACH THE COAST BY 12Z FRIDAY.
THUNDERSTORMS WILL DEVELOP IN THE MOIST AIRMASS IN ADVANCE OF THE
FRONT THURSDAY... AND MODEST INSTABILITY OF 500-1000 J/KG MLCAPE AND
0-6 KM BULK SHEAR VALUES OF 25 KTS WILL SUPPORT A FEW MULTICELL
CLUSTERS. BEST UPPER LEVEL FORCING REMAINS NORTH OF THE AREA... AND
WITH THE STRONGEST LOW LEVEL FORCING ASSOCIATED WITH THE FRONT NOT
MAKING IT THROUGH THE AREA UNTIL LATE THURSDAY... SEVERE POTENTIAL
IS LOW. HIGHS LOW TO MID 80S... LOWS IN THE 60S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AS OF 310 PM WEDNESDAY...
FRIDAY THROUGH SATURDAY NIGHT...
A DEEP UPPER LEVEL TROUGH WILL SWING ACROSS CENTRAL NC FRIDAY AND
EXIT THE REGION FRIDAY NIGHT. MAY SEE A FEW INSTABILITY SHOWERS
WITH THE PASSAGE OF THIS SYSTEM HOWEVER MODEL RH CROSS SECTIONS
DEPICT THE AIR MASS DRYING OUT APPRECIABLY ABOVE 5000-8000FT BY
EARLY AFTERNOON. FOR NOW WILL LIMIT POPS TO SLIGHT CHANCE. OTHERWISE
BRISK NW FLOW WILL ADVECT COOLER MORE STABLE AIR INTO THE REGION.
SUSTAINED NW WINDS 10-15 MPH WITH GUSTS AROUND 25 MPH PROBABLE. THE
ARRIVAL OF THIS AIR MASS WILL RESULT IN COOLER CONDITIONS WITH
AFTERNOON MAX TEMPS IN THE LOWER 70S NORTH TO UPPER 70S FAR SE.
FRIDAY NIGHT...SKIES WILL CLEAR EARLY THOUGH A STEADY NW SFC WIND
WILL BE SLOW TO SUBSIDE. LOW LEVEL THICKNESSES CLUSTERING AROUND
1340M. HISTORICALLY...THIS SUGGEST MIN TEMPS NEAR 40-LOWER 40S.
FAVOR THE HIGH END OF THIS REGION DUE TO EXPECTED MIXING WELL INTO
THE NIGHT. MIN TEMPS 45-50.
SATURDAY INTO SATURDAY NIGHT...CANADIAN HIGH PRESSURE OVER THE LOWER
GREAT LAKES WILL BUILD/EXTEND INTO OUR REGION SATURDAY INTO SATURDAY
NIGHT. THIS WEATHER SYSTEM WILL RESULT IN A DRY WEATHER PATTERN WITH
BELOW NORMAL TEMPS. AFTERNOON THICKNESSES PROJECTED TO BE ABOUT 35M
BELOW NORMAL...SUPPORTIVE OF TEMPS CLOSE TO 10 DEGREES BELOW NORMAL.
ALLOWING FOR WARMTH FROM LATE MAY SUN...EXPECT AFTERNOON HIGH TEMPS
IN THE MID-UPPER 70S. MOS GUIDANCE LIKELY TRENDING TOWARD
CLIMATOLOGY BY SATURDAY NIGHT. WITH SFC RIDGE OVERHEAD AND CORE OF
LOW LEVEL DRY ACROSS THE REGION...TEMPS SHOULD COOL QUICKLY INT EH
EVENING THEN STABILIZE. MODEL RH CROSS SECTIONS HINT AT INCREASING
MID-HIGH LEVEL CLOUDS OVERNIGHT INTO EARLY SUNDAY. FIRST GLANCE
SUGGEST THAT CLOUD COVERAGE MAY INITIALLY BE THIN AND SPOTTY SO
COULD SEE DECENT NOCTURNAL COOLING. FAVOR MIN TEMPS A FEW DEGREES
COOLER THAN PREVIOUS FORECAST WITH MIN TEMPS IN THE MID-UPPER 40S.
SUNDAY INTO MONDAY...DEEP UPPER LEVEL LOW OVER NORTHERN NEW
ENGLAND-CANADIAN MARITIME PROVINCES WILL MAINTAIN A NW FLOW OVER THE
FORECAST AREA SUNDAY. WEAK PERTURBATIONS IN THIS FLOW ALOFT WORKING
WITH AVAILABLE MOISTURE WILL LIKELY CAUSE AN INCREASE IN MID-HIGH
LEVEL CLOUDINESS SUNDAY INTO SUNDAY NIGHT...MORE SO ACROSS OUR WEST
AND SOUTH SECTIONS AND LEAST IN THE NE. A MODIFYING AIR MASS WILL
LEAD TO SLIGHTLY WARMER CONDITIONS WITH AFTERNOON TEMPS IN THE
MID-UPPER 70S...AND AND MIN TEMPS IN THE MID 50S. 00Z ECMWF SUGGEST
THAT THERE MAY BE ENOUGH AMPLITUDE TO AN APPROACHING MID LEVEL
TROUGH TO WARRANT A SLIGHT-SMALL CHANCE POP ACROSS CENTRAL NC MONDAY
AFTERNOON-MONDAY EVENING.
TUESDAY INTO WEDNESDAY...AN AMPLIFYING MID-UPPER LEVEL RIDGE OVER
THE EASTERN HALF OF THE U.S. WILL PLACE CENTRAL NC BACK INTO A
SUMMER-LIKE PATTERN WITH A SFC HIGH ANCHORED OFFSHORE BUT EXTENDING
WESTWARD INTO THE SE U.S. THIS SUGGEST A RETURN TO WARM AND SLIGHTLY
HUMID CONDITIONS WITH AFTERNOON TEMPS IN THE LOW-MID 80S AND MIN
TEMPS 60-65. CONVECTION APPEARS TO BE DIURNALLY DRIVEN...ADDED BY A
SEABREEZE TO SE AND NW FLOW ALOFT SENDING CONVECTION OFF THE HIGHER
TERRAIN INTO THE WESTERN PIEDMONT. POPS NO HIGHER THAN SLIGHT
CHANCE-SMALL CHANCE AT THIS TIME...CONFINED TO THE AFTERNOON-EVENING
HOURS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 120 PM WEDNESDAY...
24 HOUR TAF PERIOD: AS OF 17Z MOST SITES ACROSS CENTRAL NORTH
CAROLINA WERE REPORTING VFR CONDITIONS WITH SOUTH SOUTHWESTERLY
WINDS 5-10 KNOTS GUSTING TO 15 KNOTS. EXPECT GUSTS TO CONTINUE
THROUGH SUNSET. AS FAR AS PRECIPITATION GOES THIS AFTERNOON...MOST
CONVECTION ON THE RADAR AT THIS TIME IS ASSOCIATED WITH THE SEA
BREEZE. AS HEATING CONTINUES AND OTHER BOUNDARIES FORM BASED ON
BREAKS IN THE CLOUDS...EXPECT FURTHER DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS THIS AFTERNOON. EASTERN SITES SUCH AS KRWI AND KFAY
WILL BE THE MOST LIKELY TO SEE STORMS THIS AFTERNOON. SUB-VFR
CONDITIONS WILL AGAIN BE POSSIBLE TONIGHT MAINLY AFTER 6Z IN THE
FORM OF LOW STRATUS WITH BASES AROUND 1000 FT. IT IS POSSIBLE THAT
WE WILL MAINTAIN MVFR CEILINGS THROUGH THE END OF THE TAF PERIOD.
FOR NOW HAVE CEILINGS BREAKING BETWEEN 14-16Z FROM WEST TO EAST BUT
HOVERING NEAR 3500 FT. AS FRONT APPROACHES THE THREAT FOR SHOWERS
AND THUNDERSTORMS WILL INCREASE GOING INTO THURSDAY AFTERNOON. WINDS
THURSDAY AFTERNOON WILL REMAIN LARGELY SOUTHWESTERLY NEAR 10 KNOTS
GUSTING TO 15-20 KTS.
LONG TERM: ADVERSE AVIATION CONDITIONS ARE EXPECTED TO PREVAIL
THROUGH EARLY FRIDAY MORNING AS THE FRONTAL SYSTEM MOVES THROUGH THE
AREA. FRIDAY WILL SEE A PROLONGED RETURN TO VFR CONDITIONS THROUGH
MONDAY MAKING CONDITIONS VERY FAVORABLE FOR GENERAL AVIATION THROUGH
THE EXTENDED MEMORIAL DAY WEEKEND.
&&
.CLIMATE...
MORNING LOW TEMPERATURES ON THE 25TH AND 26TH ARE EXPECTED TO BE A
FEW DEGREES SHY OF RECORD MIN TEMPS FOR THE DATE.
RECORD MIN TEMP/YEAR SET MAY 25TH MAY 26TH
RDU 43 / 1967 43 / 1979
GSO 43 / 1956 42 / 1930
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...ELLIS
SHORT TERM...SEC
LONG TERM...WSS
AVIATION...ELLIS
CLIMATE...RAH
000
FXUS62 KRAH 221724
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
124 PM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE MIDDLE ATLANTIC TODAY. A
SURFACE PRESSURE TROUGH WILL DEVELOP IN THE LEE OF THE APPALACHIANS
THURSDAY...FOLLOWED BY THE PASSAGE OF A COLD FRONT THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM WEDNESDAY...
QUIETER DAY TODAY AS CENTRAL NC SITS IN BETWEEN A SHORTWAVE SYSTEM
JUST OFF THE COAST AND A LARGER FRONTAL SYSTEM CURRENTLY STRETCHING
ACROSS THE MISSISSIPPI VALLEY THAT WILL CONTINUE TO PUSH EASTWARD
TODAY WITH THE PARENT LOW MOVING TOWARDS THE SOUTHERN GREAT LAKES.
FOR CENTRAL NC THE BIGGEST DIFFERENCE BETWEEN TODAY AND PREVIOUS
DAYS IS THE WEAKENING OF THE SHORTWAVE TROUGH AND THE PRESENCE OF
HIGH PRESSURE AT THE UPPER LEVELS OF THE ATMOSPHERE. IN ADDITION
PRECIPITABLE WATER VALUES HAVE RELAXED SOMEWHAT...NEAR 1.5 INCHES
WITH HIGHER VALUES SOUTH AND EAST AND DRIER CONDITIONS ACROSS THE
NORTHWESTERN PIEDMONT. CURRENT MVFR CEILINGS WILL GRADUALLY LIFT OUT
AND SET THE STAGE AGAIN FOR CUMULIFORM DEVELOPMENT LEADING TO
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. COVERAGE OF STORMS SHOULD
BE LESS THAN PREVIOUS DAYS AND SURFACE BOUNDARIES WILL ONCE AGAIN BE
THE CATALYST. SEVERE PARAMETERS WILL ONCE AGAIN BE VERY WEAK
OUTSIDE OF THE INSTABILITY WITH SHEAR ONLY AT 10 KNOTS OR SO AND
WEAK LAPSE RATES NEAR 5.5 DEG/KM. ML CAPE VALUES ONLY PREDICTED TO
BE ABOUT 800 J/KG OR SO. THEREFORE NOT EXPECTING ANY SEVERE WX THIS
AFTERNOON BUT POP UP SHOWERS AND THUNDERSTORMS WILL STILL BE
POSSIBLE...ESPECIALLY NEAR SURFACE BOUNDARIES. HIGH TEMPERATURES
TODAY SHOULD BENEFIT FROM BETTER INSOLATION AFTER MVFR CEILINGS BURN
OFF. EXPECT MIDDLE 80S ACROSS THE CWA TODAY. THERE IS THE POTENTIAL
FOR MORE LOW STRATUS TONIGHT AFTER SUNSET WITH CEILINGS CLOSER TO
2000 FEET. LOWS IN THE MIDDLE 60S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 308 AM WEDNESDAY...
COLD FRONT WILL CROSS THE AREA... ENTERING THE STATE FROM THE WEST
THURSDAY EVENING... AND WILL REACH THE COAST BY 12Z FRIDAY.
THUNDERSTORMS WILL DEVELOP IN THE MOIST AIRMASS IN ADVANCE OF THE
FRONT THURSDAY... AND MODEST INSTABILITY OF 500-1000 J/KG MLCAPE AND
0-6 KM BULK SHEAR VALUES OF 25 KTS WILL SUPPORT A FEW MULTICELL
CLUSTERS. BEST UPPER LEVEL FORCING REMAINS NORTH OF THE AREA... AND
WITH THE STRONGEST LOW LEVEL FORCING ASSOCIATED WITH THE FRONT NOT
MAKING IT THROUGH THE AREA UNTIL LATE THURSDAY... SEVERE POTENTIAL
IS LOW. HIGHS LOW TO MID 80S... LOWS IN THE 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
BEHIND THE FRONT... NORTHWESTERLY FLOW WILL USHER IN A MUCH DRIER
AIRMASS... AND PRECIPITATION WILL END FROM WEST TO EAST EARLY
FRIDAY. TEMPERATURES WILL BE SEVERAL DEGREES BELOW NORMAL THROUGH
THE WEEKEND... WITH HIGHS IN THE 70S. COOLEST LOWS FRIDAY NIGHT...
IN THE UPPER 40S TO LOW 50S... THEN LOW TO MID 50S SATURDAY NIGHT.
MOISTURE WILL INCREASE AGAIN ON MONDAY AS THE FLOW BECOMES MORE
SOUTHERLY... WITH PWAT VALUES AGAIN CLIMBING TO NEAR 1.5 INCHES.
GUIDANCE INDICATES A WARM FRONT WILL BE IN THE VICINITY OF THE
MIDATLANTIC MONDAY EVENING INTO TUESDAY... AND TEMPERATURES TUESDAY
WILL REBOUND TO NEAR NORMAL... UPPER 70S TO LOW 80S. DEPENDING ON
THE LOCATION OF THE FRONT... ISENTROPICALLY DRIVEN SHOWERS ARE
POSSIBLE... AND WILL CONTINUE WITH SLIGHT CHANCE POPS.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 120 PM WEDNESDAY...
24 HOUR TAF PERIOD: AS OF 17Z MOST SITES ACROSS CENTRAL NORTH
CAROLINA WERE REPORTING VFR CONDITIONS WITH SOUTH SOUTHWESTERLY
WINDS 5-10 KNOTS GUSTING TO 15 KNOTS. EXPECT GUSTS TO CONTINUE
THROUGH SUNSET. AS FAR AS PRECIPITATION GOES THIS AFTERNOON...MOST
CONVECTION ON THE RADAR AT THIS TIME IS ASSOCIATED WITH THE SEA
BREEZE. AS HEATING CONTINUES AND OTHER BOUNDARIES FORM BASED ON
BREAKS IN THE CLOUDS...EXPECT FURTHER DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS THIS AFTERNOON. EASTERN SITES SUCH AS KRWI AND KFAY
WILL BE THE MOST LIKELY TO SEE STORMS THIS AFTERNOON. SUB-VFR
CONDITIONS WILL AGAIN BE POSSIBLE TONIGHT MAINLY AFTER 6Z IN THE
FORM OF LOW STRATUS WITH BASES AROUND 1000 FT. IT IS POSSIBLE THAT
WE WILL MAINTAIN MVFR CEILINGS THROUGH THE END OF THE TAF PERIOD.
FOR NOW HAVE CEILINGS BREAKING BETWEEN 14-16Z FROM WEST TO EAST BUT
HOVERING NEAR 3500 FT. AS FRONT APPROACHES THE THREAT FOR SHOWERS
AND THUNDERSTORMS WILL INCREASE GOING INTO THURSDAY AFTERNOON. WINDS
THURSDAY AFTERNOON WILL REMAIN LARGELY SOUTHWESTERLY NEAR 10 KNOTS
GUSTING TO 15-20 KTS.
LONG TERM: ADVERSE AVIATION CONDITIONS ARE EXPECTED TO PREVAIL
THROUGH EARLY FRIDAY MORNING AS THE FRONTAL SYSTEM MOVES THROUGH THE
AREA. FRIDAY WILL SEE A PROLONGED RETURN TO VFR CONDITIONS THROUGH
MONDAY MAKING CONDITIONS VERY FAVORABLE FOR GENERAL AVIATION THROUGH
THE EXTENDED MEMORIAL DAY WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...ELLIS
SHORT TERM...SEC
LONG TERM...SEC
AVIATION...ELLIS
000
FXUS62 KRAH 221422
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1022 AM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE MIDDLE ATLANTIC TODAY. A
SURFACE PRESSURE TROUGH WILL DEVELOP IN THE LEE OF THE APPALACHIANS
THURSDAY...FOLLOWED BY THE PASSAGE OF A COLD FRONT THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM WEDNESDAY...
QUIETER DAY TODAY AS CENTRAL NC SITS IN BETWEEN A SHORTWAVE SYSTEM
JUST OFF THE COAST AND A LARGER FRONTAL SYSTEM CURRENTLY STRETCHING
ACROSS THE MISSISSIPPI VALLEY THAT WILL CONTINUE TO PUSH EASTWARD
TODAY WITH THE PARENT LOW MOVING TOWARDS THE SOUTHERN GREAT LAKES.
FOR CENTRAL NC THE BIGGEST DIFFERENCE BETWEEN TODAY AND PREVIOUS
DAYS IS THE WEAKENING OF THE SHORTWAVE TROUGH AND THE PRESENCE OF
HIGH PRESSURE AT THE UPPER LEVELS OF THE ATMOSPHERE. IN ADDITION
PRECIPITABLE WATER VALUES HAVE RELAXED SOMEWHAT...NEAR 1.5 INCHES
WITH HIGHER VALUES SOUTH AND EAST AND DRIER CONDITIONS ACROSS THE
NORTHWESTERN PIEDMONT. CURRENT MVFR CEILINGS WILL GRADUALLY LIFT OUT
AND SET THE STAGE AGAIN FOR CUMULIFORM DEVELOPMENT LEADING TO
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. COVERAGE OF STORMS SHOULD
BE LESS THAN PREVIOUS DAYS AND SURFACE BOUNDARIES WILL ONCE AGAIN BE
THE CATALYST. SEVERE PARAMETERS WILL ONCE AGAIN BE VERY WEAK
OUTSIDE OF THE INSTABILITY WITH SHEAR ONLY AT 10 KNOTS OR SO AND
WEAK LAPSE RATES NEAR 5.5 DEG/KM. ML CAPE VALUES ONLY PREDICTED TO
BE ABOUT 800 J/KG OR SO. THEREFORE NOT EXPECTING ANY SEVERE WX THIS
AFTERNOON BUT POP UP SHOWERS AND THUNDERSTORMS WILL STILL BE
POSSIBLE...ESPECIALLY NEAR SURFACE BOUNDARIES. HIGH TEMPERATURES
TODAY SHOULD BENEFIT FROM BETTER INSOLATION AFTER MVFR CEILINGS BURN
OFF. EXPECT MIDDLE 80S ACROSS THE CWA TODAY. THERE IS THE POTENTIAL
FOR MORE LOW STRATUS TONIGHT AFTER SUNSET WITH CEILINGS CLOSER TO
2000 FEET. LOWS IN THE MIDDLE 60S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 308 AM WEDNESDAY...
COLD FRONT WILL CROSS THE AREA... ENTERING THE STATE FROM THE WEST
THURSDAY EVENING... AND WILL REACH THE COAST BY 12Z FRIDAY.
THUNDERSTORMS WILL DEVELOP IN THE MOIST AIRMASS IN ADVANCE OF THE
FRONT THURSDAY... AND MODEST INSTABILITY OF 500-1000 J/KG MLCAPE AND
0-6 KM BULK SHEAR VALUES OF 25 KTS WILL SUPPORT A FEW MULTICELL
CLUSTERS. BEST UPPER LEVEL FORCING REMAINS NORTH OF THE AREA... AND
WITH THE STRONGEST LOW LEVEL FORCING ASSOCIATED WITH THE FRONT NOT
MAKING IT THROUGH THE AREA UNTIL LATE THURSDAY... SEVERE POTENTIAL
IS LOW. HIGHS LOW TO MID 80S... LOWS IN THE 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
BEHIND THE FRONT... NORTHWESTERLY FLOW WILL USHER IN A MUCH DRIER
AIRMASS... AND PRECIPITATION WILL END FROM WEST TO EAST EARLY
FRIDAY. TEMPERATURES WILL BE SEVERAL DEGREES BELOW NORMAL THROUGH
THE WEEKEND... WITH HIGHS IN THE 70S. COOLEST LOWS FRIDAY NIGHT...
IN THE UPPER 40S TO LOW 50S... THEN LOW TO MID 50S SATURDAY NIGHT.
MOISTURE WILL INCREASE AGAIN ON MONDAY AS THE FLOW BECOMES MORE
SOUTHERLY... WITH PWAT VALUES AGAIN CLIMBING TO NEAR 1.5 INCHES.
GUIDANCE INDICATES A WARM FRONT WILL BE IN THE VICINITY OF THE
MIDATLANTIC MONDAY EVENING INTO TUESDAY... AND TEMPERATURES TUESDAY
WILL REBOUND TO NEAR NORMAL... UPPER 70S TO LOW 80S. DEPENDING ON
THE LOCATION OF THE FRONT... ISENTROPICALLY DRIVEN SHOWERS ARE
POSSIBLE... AND WILL CONTINUE WITH SLIGHT CHANCE POPS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 745 AM WEDNESDAY...
WIDESPREAD MVFR CEILINGS EARLY THIS MORNING WILL GIVE WAY TO A
SCATTERED-BROKEN VFR CLOUD BASES BY 10-11 AM. AS THE AIR MASS HEATS
UP THIS AFTERNOON AND BECOMES SLIGHTLY UNSTABLE...SCATTERED
CONVECTION WILL DEVELOP...ESPECIALLY AFTER 2 PM. THE SHOWERS AND
THUNDERSTORMS MAY BE A LITTLE MORE CONCENTRATED NEAR AND EAST OF
KFAY...AND NEAR AND WEST OF KINT AND KGSO. EXPECT MVFR CEILINGS AND
VISIBILITY IN VICINITY OF THE CONVECTION. THE BULK OF THE SHOWERS
AND STORMS WILL DIMINISH AFTER 8 PM.
MVFR CEILINGS DUE TO STRATUS WILL DEVELOP LATE TONIGHT AND PERSIST
INTO EARLY THURSDAY MORNING. A COLD FRONT CURRENTLY ACROSS THE OH
AND TN VALLEYS WILL CONTINUE TO DRIFT EAST AND SHOULD CROSS CENTRAL
NC LATE THURSDAY AND THURSDAY EVENING. AHEAD OF THE FRONT...NUMEROUS
SHOWERS AND SCATTERED THUNDERSTORMS AND ASSOCIATED MVFR/IFR
CONDITIONS WILL OCCUR. THE HIGHEST CONCENTRATION OF SHOWERS AND
STORMS WILL OCCUR IN THE AFTERNOON THROUGH THE EVENING HOURS WITH
CONVECTION DIMINISHING AFTER MIDNIGHT.
CANADIAN HIGH PRESSURE WILL BUILD INTO OUR AREA FROM THE NW FRIDAY
IN THE WAKE OF THE DEPARTING SYSTEM. THIS WEATHER SYSTEM WILL ADVECT
DRIER AND MORE STABLE AIR INTO THE CAROLINAS...RESULTING IN A
PROLONGED PERIOD OF VFR CONDITIONS THAT SHOULD LAST THROUGH SUNDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...ELLIS
SHORT TERM...SEC
LONG TERM...SEC
AVIATION...WSS
000
FXUS62 KRAH 221143
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
745 AM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE MIDDLE ATLANTIC TODAY. A
SURFACE PRESSURE TROUGH WILL DEVELOP IN THE LEE OF THE APPALACHIANS
THURSDAY...FOLLOWED BY THE PASSAGE OF A COLD FRONT THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM WEDNESDAY...
THE MID LEVEL TROUGH THAT HAS PROMOTED NUMEROUS TO WIDESPREAD
DOWNPOURS IN RECENT DAYS IS NO LONGER DISCERNIBLE IN REGIONAL VWP
DATA. BERMUDA HIGH PRESSURE WILL CONSEQUENTLY BRIEFLY EXERT THE
DOMINANT INFLUENCE TO WEATHER CONDITIONS OVER CENTRAL NC TODAY...SO
CONVECTIVE COVERAGE SHOULD BE MUCH LESS THAN PREVIOUS DAYS...AND
FOCUSED BY THE SEA BREEZE AND OTHER SMALLER SCALE/LOWER
PREDICTABILITY DIFFERENTIAL HEATING OR REMNANT OUTFLOW BOUNDARIES.
A BLANKET 20-30 PERCENT POP IS ACCORDINGLY WARRANTED...WITH RELATIVE
HIGHEST CHANCES ASSOCIATED WITH THE SEA BREEZE OVER THE COASTAL
PLAIN AND EASTERN SANDHILLS AND PIEDMONT. DESPITE WHAT SOME OF THE
NWP GUIDANCE WOULD SUGGEST...IT SEEMS IMPROBABLE THAT ANY
MOUNTAIN-INDUCED CONVECTION WOULD AFFECT THE WESTERN
PIEDMONT...OWING TO SOUTH TO SOUTH SOUTHWESTERLY STEERING FLOW THAT
WOULD HOLD STORM MOTIONS/PROPAGATION WEST OF THE YADKIN RIVER. HIGHS
SIMILAR TO THOSE OF TUESDAY...GENERALLY IN THE MIDDLE 80S.
HEIGHT FALLS IN ASSOCIATION WITH THE COMPLEX TROUGH ALOFT
APPROACHING FROM THE CENTRAL CONUS...ON THE ORDER OF 20-30 METERS AT
H5...WILL SPREAD EASTWARD ACROSS CENTRAL NC TONIGHT. WHILE THESE
HEIGHT FALLS ARE APT TO SUPPORT A BAND OF PRE-FRONTAL SHOWERS AND
STORMS FROM THE TN VALLEY TO THE APPALACHIANS BY THIS EVENING...IT
SEEMS PROBABLE THAT THIS CONVECTION WILL WEAKEN CONSIDERABLY AS IT
EMERGES INTO AN INCREASINGLY STABLE...NOCTURNALLY-COOLED BOUNDARY
LAYER IN THE LEE OF THE MOUNTAINS - A SOLUTION DEPICTED WELL BY THE
00Z SPC NMM. AS SUCH...WILL INDICATE A HIGH CHANCE OF MAINLY
LEFT-OVER SHOWERS INTO THE SOUTHERN AND WESTERN PIEDMONT AFTER 11
PM...TAPERING TO SLIGHT CHANCE RANGE AROUND THE TRIANGLE AREA...TO
DRY ROUGHLY EAST OF I-95. A CONTINUED VERY MOIST AIR MASS WILL
RESULT IN ADDITIONAL LOW STRATUS DEVELOPMENT THROUGH THU MORNING...
WITH PERSISTENCE LOWS IN THE MIDDLE 60S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 308 AM WEDNESDAY...
COLD FRONT WILL CROSS THE AREA... ENTERING THE STATE FROM THE WEST
THURSDAY EVENING... AND WILL REACH THE COAST BY 12Z FRIDAY.
THUNDERSTORMS WILL DEVELOP IN THE MOIST AIRMASS IN ADVANCE OF THE
FRONT THURSDAY... AND MODEST INSTABILITY OF 500-1000 J/KG MLCAPE AND
0-6 KM BULK SHEAR VALUES OF 25 KTS WILL SUPPORT A FEW MULTICELL
CLUSTERS. BEST UPPER LEVEL FORCING REMAINS NORTH OF THE AREA... AND
WITH THE STRONGEST LOW LEVEL FORCING ASSOCIATED WITH THE FRONT NOT
MAKING IT THROUGH THE AREA UNTIL LATE THURSDAY... SEVERE POTENTIAL
IS LOW. HIGHS LOW TO MID 80S... LOWS IN THE 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
BEHIND THE FRONT... NORTHWESTERLY FLOW WILL USHER IN A MUCH DRIER
AIRMASS... AND PRECIPITATION WILL END FROM WEST TO EAST EARLY
FRIDAY. TEMPERATURES WILL BE SEVERAL DEGREES BELOW NORMAL THROUGH
THE WEEKEND... WITH HIGHS IN THE 70S. COOLEST LOWS FRIDAY NIGHT...
IN THE UPPER 40S TO LOW 50S... THEN LOW TO MID 50S SATURDAY NIGHT.
MOISTURE WILL INCREASE AGAIN ON MONDAY AS THE FLOW BECOMES MORE
SOUTHERLY... WITH PWAT VALUES AGAIN CLIMBING TO NEAR 1.5 INCHES.
GUIDANCE INDICATES A WARM FRONT WILL BE IN THE VICINITY OF THE
MIDATLANTIC MONDAY EVENING INTO TUESDAY... AND TEMPERATURES TUESDAY
WILL REBOUND TO NEAR NORMAL... UPPER 70S TO LOW 80S. DEPENDING ON
THE LOCATION OF THE FRONT... ISENTROPICALLY DRIVEN SHOWERS ARE
POSSIBLE... AND WILL CONTINUE WITH SLIGHT CHANCE POPS.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 745 AM WEDNESDAY...
WIDESPREAD MVFR CEILINGS EARLY THIS MORNING WILL GIVE WAY TO A
SCATTERED-BROKEN VFR CLOUD BASES BY 10-11 AM. AS THE AIR MASS HEATS
UP THIS AFTERNOON AND BECOMES SLIGHTLY UNSTABLE...SCATTERED
CONVECTION WILL DEVELOP...ESPECIALLY AFTER 2 PM. THE SHOWERS AND
THUNDERSTORMS MAY BE A LITTLE MORE CONCENTRATED NEAR AND EAST OF
KFAY...AND NEAR AND WEST OF KINT AND KGSO. EXPECT MVFR CEILINGS AND
VISIBILITY IN VICINITY OF THE CONVECTION. THE BULK OF THE SHOWERS
AND STORMS WILL DIMINISH AFTER 8 PM.
MVFR CEILINGS DUE TO STRATUS WILL DEVELOP LATE TONIGHT AND PERSIST
INTO EARLY THURSDAY MORNING. A COLD FRONT CURRENTLY ACROSS THE OH
AND TN VALLEYS WILL CONTINUE TO DRIFT EAST AND SHOULD CROSS CENTRAL
NC LATE THURSDAY AND THURSDAY EVENING. AHEAD OF THE FRONT...NUMEROUS
SHOWERS AND SCATTERED THUNDERSTORMS AND ASSOCIATED MVFR/IFR
CONDITIONS WILL OCCUR. THE HIGHEST CONCENTRATION OF SHOWERS AND
STORMS WILL OCCUR IN THE AFTERNOON THROUGH THE EVENING HOURS WITH
CONVECTION DIMINISHING AFTER MIDNIGHT.
CANADIAN HIGH PRESSURE WILL BUILD INTO OUR AREA FROM THE NW FRIDAY
IN THE WAKE OF THE DEPARTING SYSTEM. THIS WEATHER SYSTEM WILL ADVECT
DRIER AND MORE STABLE AIR INTO THE CAROLINAS...RESULTING IN A
PROLONGED PERIOD OF VFR CONDITIONS THAT SHOULD LAST THROUGH SUNDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...SEC
LONG TERM...SEC
AVIATION...WSS
000
FXUS62 KRAH 220719
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
319 AM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE MIDDLE ATLANTIC TODAY. A
SURFACE PRESSURE TROUGH WILL DEVELOP IN THE LEE OF THE APPALACHIANS
THURSDAY...FOLLOWED BY THE PASSAGE OF A COLD FRONT THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 315 AM WEDNESDAY...
THE MID LEVEL TROUGH THAT HAS PROMOTED NUMEROUS TO WIDESPREAD
DOWNPOURS IN RECENT DAYS IS NO LONGER DISCERNIBLE IN REGIONAL VWP
DATA. BERMUDA HIGH PRESSURE WILL CONSEQUENTLY BRIEFLY EXERT THE
DOMINANT INFLUENCE TO WEATHER CONDITIONS OVER CENTRAL NC TODAY...SO
CONVECTIVE COVERAGE SHOULD BE MUCH LESS THAN PREVIOUS DAYS...AND
FOCUSED BY THE SEA BREEZE AND OTHER SMALLER SCALE/LOWER
PREDICTABILITY DIFFERENTIAL HEATING OR REMNANT OUTFLOW BOUNDARIES.
A BLANKET 20-30 PERCENT POP IS ACCORDINGLY WARRANTED...WITH RELATIVE
HIGHEST CHANCES ASSOCIATED WITH THE SEA BREEZE OVER THE COASTAL
PLAIN AND EASTERN SANDHILLS AND PIEDMONT. DESPITE WHAT SOME OF THE
NWP GUIDANCE WOULD SUGGEST...IT SEEMS IMPROBABLE THAT ANY
MOUNTAIN-INDUCED CONVECTION WOULD AFFECT THE WESTERN
PIEDMONT...OWING TO SOUTH TO SOUTH SOUTHWESTERLY STEERING FLOW THAT
WOULD HOLD STORM MOTIONS/PROPAGATION WEST OF THE YADKIN RIVER. HIGHS
SIMILAR TO THOSE OF TUESDAY...GENERALLY IN THE MIDDLE 80S.
HEIGHT FALLS IN ASSOCIATION WITH THE COMPLEX TROUGH ALOFT
APPROACHING FROM THE CENTRAL CONUS...ON THE ORDER OF 20-30 METERS AT
H5...WILL SPREAD EASTWARD ACROSS CENTRAL NC TONIGHT. WHILE THESE
HEIGHT FALLS ARE APT TO SUPPORT A BAND OF PRE-FRONTAL SHOWERS AND
STORMS FROM THE TN VALLEY TO THE APPALACHIANS BY THIS EVENING...IT
SEEMS PROBABLE THAT THIS CONVECTION WILL WEAKEN CONSIDERABLY AS IT
EMERGES INTO AN INCREASINGLY STABLE...NOCTURNALLY-COOLED BOUNDARY
LAYER IN THE LEE OF THE MOUNTAINS - A SOLUTION DEPICTED WELL BY THE
00Z SPC NMM. AS SUCH...WILL INDICATE A HIGH CHANCE OF MAINLY
LEFT-OVER SHOWERS INTO THE SOUTHERN AND WESTERN PIEDMONT AFTER 11
PM...TAPERING TO SLIGHT CHANCE RANGE AROUND THE TRIANGLE AREA...TO
DRY ROUGHLY EAST OF I-95. A CONTINUED VERY MOIST AIR MASS WILL
RESULT IN ADDITIONAL LOW STRATUS DEVELOPMENT THROUGH THU MORNING...
WITH PERSISTENCE LOWS IN THE MIDDLE 60S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 308 AM WEDNESDAY...
COLD FRONT WILL CROSS THE AREA... ENTERING THE STATE FROM THE WEST
THURSDAY EVENING... AND WILL REACH THE COAST BY 12Z FRIDAY.
THUNDERSTORMS WILL DEVELOP IN THE MOIST AIRMASS IN ADVANCE OF THE
FRONT THURSDAY... AND MODEST INSTABILITY OF 500-1000 J/KG MLCAPE AND
0-6 KM BULK SHEAR VALUES OF 25 KTS WILL SUPPORT A FEW MULTICELL
CLUSTERS. BEST UPPER LEVEL FORCING REMAINS NORTH OF THE AREA... AND
WITH THE STRONGEST LOW LEVEL FORCING ASSOCIATED WITH THE FRONT NOT
MAKING IT THROUGH THE AREA UNTIL LATE THURSDAY... SEVERE POTENTIAL
IS LOW. HIGHS LOW TO MID 80S... LOWS IN THE 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
BEHIND THE FRONT... NORTHWESTERLY FLOW WILL USHER IN A MUCH DRIER
AIRMASS... AND PRECIPITATION WILL END FROM WEST TO EAST EARLY
FRIDAY. TEMPERATURES WILL BE SEVERAL DEGREES BELOW NORMAL THROUGH
THE WEEKEND... WITH HIGHS IN THE 70S. COOLEST LOWS FRIDAY NIGHT...
IN THE UPPER 40S TO LOW 50S... THEN LOW TO MID 50S SATURDAY NIGHT.
MOISTURE WILL INCREASE AGAIN ON MONDAY AS THE FLOW BECOMES MORE
SOUTHERLY... WITH PWAT VALUES AGAIN CLIMBING TO NEAR 1.5 INCHES.
GUIDANCE INDICATES A WARM FRONT WILL BE IN THE VICINITY OF THE
MIDATLANTIC MONDAY EVENING INTO TUESDAY... AND TEMPERATURES TUESDAY
WILL REBOUND TO NEAR NORMAL... UPPER 70S TO LOW 80S. DEPENDING ON
THE LOCATION OF THE FRONT... ISENTROPICALLY DRIVEN SHOWERS ARE
POSSIBLE... AND WILL CONTINUE WITH SLIGHT CHANCE POPS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SATURDAY/...
AS OF 240 AM WEDNESDAY...
A CONTINUED VERY MOIST AIR MASS WILL RESULT IN A HIGH CHANCE OF
LIFR-IFR CEILINGS THIS MORNING. THESE CEILINGS WILL LIFT AND SCATTER
TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR MASS
WILL ALSO CAUSE WIDELY SCATTERED SHOWERS AND STORMS TO DEVELOP THIS
AFTERNOON...BUT WITH LESSER COVERAGE VERSUS PREVIOUS DAYS OWING TO
THE WEAKENING AND DEPARTURE OF A LIFT-INDUCING TROUGH THAT RESIDED
OVER THE AREA DURING RECENT DAYS. UNTIL A COLD FRONT SWEEPS
ACROSS CENTRAL NC THU NIGHT...THE CONTINUED VERY MOIST REGIME WILL
PROMOTE ADDITIONAL LOW STRATUS DEVELOPMENT TONIGHT...AND A CONTINUED
THREAT OF MAINLY AFTERNOON SHOWERS AND STORMS. VFR CONDITIONS WILL
OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE THROUGH THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...SEC
LONG TERM...SEC
AVIATION...MWS
000
FXUS62 KRAH 220708
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
306 AM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE MIDDLE ATLANTIC TODAY. A
SURFACE PRESSURE TROUGH WILL DEVELOP IN THE LEE OF THE APPALACHIANS
THURSDAY...FOLLOWED BY THE PASSAGE OF A COLD FRONT THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 PM TUESDAY...
THE PESKY WEAK MID-LEVEL IMPULSE THAT HAS TAKEN 3 DAYS TO CROSS THE
STATE AND LARGELY RESPONSIBLE FOR THE UNSETTLED/STORMY WEATHER
DURING THE SAME TIME...IS FINALLY IN THE PROCESS OF PUSHING OUT TO
SEA. THIS WILL SPELL FOR DRIER CONDITIONS TONIGHT THAN THAT OF THE
PAST FEW NIGHTS. WITH THAT SAID...THE NORTHERN/NORTHWESTERN PIEDMONT
COULD STILL SEE SOME ISOLATED CONVECTION OVER THE NEXT COUPLE OF
HOURS AS BAND OF COLD POOL DRIVEN CONVECTION CROSSES THE MOUNTAINS
AND MOVES NORTHEAST INTO THE VIRGINIAS.
WITH THE PLUME OF HIGH 1.5-1.7" PWAT STILL IN PLACE OVER THE
REGION...LOW CEILINGS AND FOG ARE APT TO DEVELOP AFTER MIDNIGHT.
LOWS TONIGHT IN THE MIDDLE TO UPPER 60S.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
AS OF 308 AM WEDNESDAY...
COLD FRONT WILL CROSS THE AREA... ENTERING THE STATE FROM THE WEST
THURSDAY EVENING... AND WILL REACH THE COAST BY 12Z FRIDAY.
THUNDERSTORMS WILL DEVELOP IN THE MOIST AIRMASS IN ADVANCE OF THE
FRONT THURSDAY... AND MODEST INSTABILITY OF 500-1000 J/KG MLCAPE AND
0-6 KM BULK SHEAR VALUES OF 25 KTS WILL SUPPORT A FEW MULTICELL
CLUSTERS. BEST UPPER LEVEL FORCING REMAINS NORTH OF THE AREA... AND
WITH THE STRONGEST LOW LEVEL FORCING ASSOCIATED WITH THE FRONT NOT
MAKING IT THROUGH THE AREA UNTIL LATE THURSDAY... SEVERE POTENTIAL
IS LOW. HIGHS LOW TO MID 80S... LOWS IN THE 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
BEHIND THE FRONT... NORTHWESTERLY FLOW WILL USHER IN A MUCH DRIER
AIRMASS... AND PRECIPITATION WILL END FROM WEST TO EAST EARLY
FRIDAY. TEMPERATURES WILL BE SEVERAL DEGREES BELOW NORMAL THROUGH
THE WEEKEND... WITH HIGHS IN THE 70S. COOLEST LOWS FRIDAY NIGHT...
IN THE UPPER 40S TO LOW 50S... THEN LOW TO MID 50S SATURDAY NIGHT.
MOISTURE WILL INCREASE AGAIN ON MONDAY AS THE FLOW BECOMES MORE
SOUTHERLY... WITH PWAT VALUES AGAIN CLIMBING TO NEAR 1.5 INCHES.
GUIDANCE INDICATES A WARM FRONT WILL BE IN THE VICINITY OF THE
MIDATLANTIC MONDAY EVENING INTO TUESDAY... AND TEMPERATURES TUESDAY
WILL REBOUND TO NEAR NORMAL... UPPER 70S TO LOW 80S. DEPENDING ON
THE LOCATION OF THE FRONT... ISENTROPICALLY DRIVEN SHOWERS ARE
POSSIBLE... AND WILL CONTINUE WITH SLIGHT CHANCE POPS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SATURDAY/...
AS OF 240 AM WEDNESDAY...
A CONTINUED VERY MOIST AIR MASS WILL RESULT IN A HIGH CHANCE OF
LIFR-IFR CEILINGS THIS MORNING. THESE CEILINGS WILL LIFT AND SCATTER
TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR MASS
WILL ALSO CAUSE WIDELY SCATTERED SHOWERS AND STORMS TO DEVELOP THIS
AFTERNOON...BUT WITH LESSER COVERAGE VERSUS PREVIOUS DAYS OWING TO
THE WEAKENING AND DEPARTURE OF A LIFT-INDUCING TROUGH THAT RESIDED
OVER THE AREA DURING RECENT DAYS. UNTIL A COLD FRONT SWEEPS
ACROSS CENTRAL NC THU NIGHT...THE CONTINUED VERY MOIST REGIME WILL
PROMOTE ADDITIONAL LOW STRATUS DEVELOPMENT TONIGHT...AND A CONTINUED
THREAT OF MAINLY AFTERNOON SHOWERS AND STORMS. VFR CONDITIONS WILL
OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE THROUGH THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...CBL
SHORT TERM...SEC
LONG TERM...SEC
AVIATION...MWS
000
FXUS62 KRAH 220706
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
306 AM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE MIDDLE ATLANTIC TODAY. A
SURFACE PRESSURE TROUGH WILL DEVELOP IN THE LEE OF THE APPALACHIANS
THURSDAY...FOLLOWED BY THE PASSAGE OF A COLD FRONT THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 PM TUESDAY...
THE PESKY WEAK MID-LEVEL IMPULSE THAT HAS TAKEN 3 DAYS TO CROSS THE
STATE AND LARGELY RESPONSIBLE FOR THE UNSETTLED/STORMY WEATHER
DURING THE SAME TIME...IS FINALLY IN THE PROCESS OF PUSHING OUT TO
SEA. THIS WILL SPELL FOR DRIER CONDITIONS TONIGHT THAN THAT OF THE
PAST FEW NIGHTS. WITH THAT SAID...THE NORTHERN/NORTHWESTERN PIEDMONT
COULD STILL SEE SOME ISOLATED CONVECTION OVER THE NEXT COUPLE OF
HOURS AS BAND OF COLD POOL DRIVEN CONVECTION CROSSES THE MOUNTAINS
AND MOVES NORTHEAST INTO THE VIRGINIAS.
WITH THE PLUME OF HIGH 1.5-1.7" PWAT STILL IN PLACE OVER THE
REGION...LOW CEILINGS AND FOG ARE APT TO DEVELOP AFTER MIDNIGHT.
LOWS TONIGHT IN THE MIDDLE TO UPPER 60S.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 218 PM TUESDAY...
ON WEDNESDAY CENTRAL NORTH CAROLINA WILL BE BETWEEN THE EXITING
SHORTWAVE SYSTEM THAT HAS BROUGHT US ALL OF THE RAIN OVER THE LAST
SEVERAL DAYS AND THE APPROACHING FRONTAL SYSTEM WITH THE PARENT LOW
PRESSURE SYSTEM CROSSING THE WESTERN GREAT LAKES. IT SHOULD BE THE
DRIEST DAY OF THE WEEK SO FAR BUT THERE WILL STILL BE PLENTY OF LOW
LEVEL MOISTURE CONVERGENCE BETWEEN RETURN FLOW FROM THE SURFACE HIGH
OFF OF THE ATLANTIC COAST AND SOUTHWESTERLY FLOW AHEAD OF THE
FRONTAL SYSTEM TO THE WEST. PRECIPITABLE WATERS WILL ONLY BE
SLIGHTLY LESS THAN TODAY ABOUT 1.6 INCHES OR SO IN THE EAST. SEVERE
PARAMETERS OUTSIDE OF INSTABILITY ARE ONCE AGAIN LACKING...VERY
SIMILAR TO THE ENVIRONMENT SEEN OVER THE LAST SEVERAL DAYS. A BIT
MORE RIDGING AND SUBSIDENCE IN THE MID TO UPPER LEVELS SHOULD KEEP
US A LITTLE DRIER THAN EARLIER IN THE WEEK BUT STILL EXPECT SOME
CONVECTIVE DEVELOPMENT BY LATE AFTERNOON. HEAVY RAIN WILL ONCE AGAIN
BE THE PRIMARY THREAT. WITH SOUTHERLY FLOW AND GREATER INSOLATION
ACROSS MUCH OF THE AREA...EXPECT HIGH TEMPERATURES AGAIN IN THE MID
80S OVER MUCH OF THE CWA. DEWPOINTS WILL REMAIN HIGH AGAIN ON
WEDNESDAY NIGHT KEEPING THE THREAT FOR LOW STRATUS AND FOG AROUND
FOR ONE MORE NIGHT AS LOWS APPROACH THE DEWPOINTS...MIDDLE TO UPPER
60S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 305 AM WEDNESDAY...
COLD FRONT WILL CROSS THE AREA... ENTERING THE STATE FROM THE WEST
THURSDAY EVENING... AND WILL REACH THE COAST BY 12Z FRIDAY.
THUNDERSTORMS WILL DEVELOP IN THE MOIST AIRMASS IN ADVANCE OF THE
FRONT THURSDAY... AND MODEST INSTABILITY OF 500-1000 J/KG MLCAPE AND
0-6 KM BULK SHEAR VALUES OF 25 KTS WILL SUPPORT A FEW MULTICELL
CLUSTERS. BEST UPPER LEVEL FORCING REMAINS NORTH OF THE AREA... AND
WITH THE STRONGEST LOW LEVEL FORCING ASSOCIATED WITH THE FRONT NOT
MAKING IT THROUGH THE AREA UNTIL LATE THURSDAY... SEVERE POTENTIAL
IS LOW. HIGHS LOW TO MID 80S... LOWS IN THE 60S.
BEHIND THE FRONT... NORTHWESTERLY FLOW WILL USHER IN A MUCH DRIER
AIRMASS... AND PRECIPITATION WILL END FROM WEST TO EAST EARLY
FRIDAY. TEMPERATURES WILL BE SEVERAL DEGREES BELOW NORMAL THROUGH
THE WEEKEND... WITH HIGHS IN THE 70S. COOLEST LOWS FRIDAY NIGHT...
IN THE UPPER 40S TO LOW 50S... THEN LOW TO MID 50S SATURDAY NIGHT.
MOISTURE WILL INCREASE AGAIN ON MONDAY AS THE FLOW BECOMES MORE
SOUTHERLY... WITH PWAT VALUES AGAIN CLIMBING TO NEAR 1.5 INCHES.
GUIDANCE INDICATES A WARM FRONT WILL BE IN THE VICINITY OF THE
MIDATLANTIC MONDAY EVENING INTO TUESDAY... AND TEMPERATURES TUESDAY
WILL REBOUND TO NEAR NORMAL... UPPER 70S TO LOW 80S. DEPENDING ON
THE LOCATION OF THE FRONT... ISENTROPICALLY DRIVEN SHOWERS ARE
POSSIBLE... AND WILL CONTINUE WITH SLIGHT CHANCE POPS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SATURDAY/...
AS OF 240 AM WEDNESDAY...
A CONTINUED VERY MOIST AIR MASS WILL RESULT IN A HIGH CHANCE OF
LIFR-IFR CEILINGS THIS MORNING. THESE CEILINGS WILL LIFT AND SCATTER
TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR MASS
WILL ALSO CAUSE WIDELY SCATTERED SHOWERS AND STORMS TO DEVELOP THIS
AFTERNOON...BUT WITH LESSER COVERAGE VERSUS PREVIOUS DAYS OWING TO
THE WEAKENING AND DEPARTURE OF A LIFT-INDUCING TROUGH THAT RESIDED
OVER THE AREA DURING RECENT DAYS. UNTIL A COLD FRONT SWEEPS
ACROSS CENTRAL NC THU NIGHT...THE CONTINUED VERY MOIST REGIME WILL
PROMOTE ADDITIONAL LOW STRATUS DEVELOPMENT TONIGHT...AND A CONTINUED
THREAT OF MAINLY AFTERNOON SHOWERS AND STORMS. VFR CONDITIONS WILL
OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE THROUGH THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...CBL
SHORT TERM...ELLIS
LONG TERM...SEC
AVIATION...MWS
000
FXUS62 KRAH 220641
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
241 AM EDT WED MAY 22 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL EXTEND INTO THE MIDDLE ATLANTIC TODAY. A
SURFACE PRESSURE TROUGH WILL DEVELOP IN THE LEE OF THE APPALACHIANS
THURSDAY...FOLLOWED BY THE PASSAGE OF A COLD FRONT THURSDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 945 PM TUESDAY...
THE PESKY WEAK MID-LEVEL IMPULSE THAT HAS TAKEN 3 DAYS TO CROSS THE
STATE AND LARGELY RESPONSIBLE FOR THE UNSETTLED/STORMY WEATHER
DURING THE SAME TIME...IS FINALLY IN THE PROCESS OF PUSHING OUT TO
SEA. THIS WILL SPELL FOR DRIER CONDITIONS TONIGHT THAN THAT OF THE
PAST FEW NIGHTS. WITH THAT SAID...THE NORTHERN/NORTHWESTERN PIEDMONT
COULD STILL SEE SOME ISOLATED CONVECTION OVER THE NEXT COUPLE OF
HOURS AS BAND OF COLD POOL DRIVEN CONVECTION CROSSES THE MOUNTAINS
AND MOVES NORTHEAST INTO THE VIRGINIAS.
WITH THE PLUME OF HIGH 1.5-1.7" PWAT STILL IN PLACE OVER THE
REGION...LOW CEILINGS AND FOG ARE APT TO DEVELOP AFTER MIDNIGHT.
LOWS TONIGHT IN THE MIDDLE TO UPPER 60S.
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 218 PM TUESDAY...
ON WEDNESDAY CENTRAL NORTH CAROLINA WILL BE BETWEEN THE EXITING
SHORTWAVE SYSTEM THAT HAS BROUGHT US ALL OF THE RAIN OVER THE LAST
SEVERAL DAYS AND THE APPROACHING FRONTAL SYSTEM WITH THE PARENT LOW
PRESSURE SYSTEM CROSSING THE WESTERN GREAT LAKES. IT SHOULD BE THE
DRIEST DAY OF THE WEEK SO FAR BUT THERE WILL STILL BE PLENTY OF LOW
LEVEL MOISTURE CONVERGENCE BETWEEN RETURN FLOW FROM THE SURFACE HIGH
OFF OF THE ATLANTIC COAST AND SOUTHWESTERLY FLOW AHEAD OF THE
FRONTAL SYSTEM TO THE WEST. PRECIPITABLE WATERS WILL ONLY BE
SLIGHTLY LESS THAN TODAY ABOUT 1.6 INCHES OR SO IN THE EAST. SEVERE
PARAMETERS OUTSIDE OF INSTABILITY ARE ONCE AGAIN LACKING...VERY
SIMILAR TO THE ENVIRONMENT SEEN OVER THE LAST SEVERAL DAYS. A BIT
MORE RIDGING AND SUBSIDENCE IN THE MID TO UPPER LEVELS SHOULD KEEP
US A LITTLE DRIER THAN EARLIER IN THE WEEK BUT STILL EXPECT SOME
CONVECTIVE DEVELOPMENT BY LATE AFTERNOON. HEAVY RAIN WILL ONCE AGAIN
BE THE PRIMARY THREAT. WITH SOUTHERLY FLOW AND GREATER INSOLATION
ACROSS MUCH OF THE AREA...EXPECT HIGH TEMPERATURES AGAIN IN THE MID
80S OVER MUCH OF THE CWA. DEWPOINTS WILL REMAIN HIGH AGAIN ON
WEDNESDAY NIGHT KEEPING THE THREAT FOR LOW STRATUS AND FOG AROUND
FOR ONE MORE NIGHT AS LOWS APPROACH THE DEWPOINTS...MIDDLE TO UPPER
60S.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 255 PM TUESDAY...
THURSDAY THROUGH FRIDAY...A COLD FRONT APPROACHES THURSDAY AND MOVES
THROUGH THURSDAY NIGHT INTO EARLY FRIDAY...FOLLOWED BY THE PRIMARY
PUSH OF COLDER AIR WITH A SECOND FRONT DURING THE DAY ON FRIDAY. ON
THURSDAY...THE RIGHT ENTRANCE REGION OF A 70KT 300MB JET GETS CLOSE
TO CENTRAL NORTH CAROLINA BUT MAINLY STAYS NORTH...WHILE 850MB LIFT
REMAINS MODEST AND 850MB THETA-E AND PRECIPITABLE WATER VALUES...
HIGHEST IN THIS PERIOD AT 1.5 INCHES AROUND 12Z THURSDAY...GRADUALLY
FALL AS FORECAST BY THE GFS THROUGH THURSDAY AND INTO FRIDAY. THOSE
PRECIPITABLE WATER VALUES FALL TO JUST BELOW AN INCH IN THE COASTAL
PLAIN AND BELOW 0.75 INCH IN THE TRIAD BY LATE FRIDAY AFTERNOON.
1000-500MB LAPSE RATES ARE MAXIMIZED ONLY TO AROUND 6.5C/KM AROUND
18Z THURSDAY...WITH AROUND 1000J/KG OF MIXED-LAYER CAPE MAINLY
TOWARD THE COASTAL PLAIN THURSDAY AFTERNOON.
850MB LIFT IS MODEST THURSDAY...AS IT APPEARS THE BEST INSTABILITY
IS OUT AHEAD OF THE BEST FORCING...WITH THE SURFACE BOUNDARY QUITE
POSSIBLY NOT MOVING INTO THE NORTHWEST PIEDMONT UNTIL VERY LATE IN
THE DAY THURSDAY. GFS BUFR SOUNDINGS...AND TO A SIMILAR DEGREE THE
NAM THOUGH THE NAM IS MORE MOIST...HAVE SLENDER CAPE AND CIN DOES
START TO INCREASE OVER A DEEP LAYER THURSDAY EVENING. MOS CHANCES
FOR SHOWERS AND THUNDERSTORMS ARE MOSTLY IN THE CHANCE RANGE
THURSDAY AND RIGHT NOW THAT SEEMS REASONABLE GIVEN WHAT CURRENTLY
APPEARS TO BE BETTER LOW-LEVEL FORCING LAGGING BETTER BOUNDARY LAYER
MOISTURE AND INSTABILITY. BUFR SOUNDINGS START TO STABILIZE THURSDAY
NIGHT AND WILL MAINTAIN A SLIGHT CHANCE OF SHOWERS OVERNIGHT TO
ACCOUNT FOR THE FIRST SURFACE FRONT...BUT IT IS POSSIBLE THAT BY THE
OVERNIGHT HOURS...PARTICULARLY ALONG AND WEST OF U.S. 1...ANY
REMAINING INSTABILITY IS SO MARGINAL IN A DRYING BOUNDARY LAYER THAT
EVEN AN ISOLATED SHOWER IS REMOTE. GIVEN THE MODEST SHEAR...MAINLY
LESS THAN 25KT 0-6KM THURSDAY AFTERNOON TOWARD INTERSTATE 95 AND
LESS TOWARD THE WEST...AND MODEST INSTABILITY WILL CONTINUE TO LEAVE
OUT THE MENTION OF SEVERE WEATHER CURRENTLY IN THE HWO. HIGHS IN THE
LOWER TO MID 80S THURSDAY CLOSER TO THE MAV MOS AND 1000-850MB
THICKNESSES...THE FORMER WHICH HAS HAD A GOOD TRACK RECORD LATELY
OVERALL COMPARED TO THE MET. OVERNIGHT LOWS THURSDAY NIGHT IN THE
UPPER 50S NORTHWEST TO THE MID 60S FAR SOUTHEAST.
FRIDAY...THE GFS HAS TRENDED TOWARD GREATER HEIGHT FALLS APPROACHING
CENTRAL NORTH CAROLINA LATE IN THE DAY. THE PRIMARY PUSH OF COLDER
AIR MOVES THROUGH DURING THE DAY BASED ON THE LATEST TIMING...AND
WHILE THERE IS AT LEAST MODEST LIFT WITH THE SURFACE BOUNDARY AND
THE HEIGHT FALLS...CURRENTLY GFS BUFR SOUNDINGS APPEAR CAPPED TO
DEEP CONVECTION. SOME OF THE GUIDANCE SUGGESTS A FEW SHOWERS IN THE
IMMEDIATE VICINITY OF INTERSTATE 95 MOVING EAST AND DEVELOPING
FURTHER TOWARD THE COAST IN MORE MOIST AIR AND ALONG THE BOUNDARY
DURING THE AFTERNOON...BUT BASED ON THE FORECAST CAP ALOFT AND DRIER
AIR MOVING ACROSS THE REGION AT THE SURFACE...WILL LEAVE OUT THE
MENTION OF SHOWERS FOR FRIDAY FOR THIS FORECAST. HIGHS FRIDAY IN THE
LOWER 70S FAR NORTHWEST...TO AROUND 80 SOUTHEAST. FRIDAY AFTERNOON
COULD END UP A LITTLE BREEZY BEHIND THE FRONTAL PASSAGE WITH
OCCASIONAL WIND GUSTS IN THE 20S KTS...POSSIBLY CLOSE TO 30MPH
BRIEFLY TOWARD THE TRIAD.
FRIDAY NIGHT THROUGH TUESDAY...A SECONDARY FRONT WILL BE MOVING
OFFSHORE LATE FRIDAY...WITH HIGH PRESSURE BUILDING INTO CENTRAL
NORTH CAROLINA FOR AT LEAST THE START OF THE WEEKEND. BASED ON THE
CONSENSUS OF THE LONG-TERM GUIDANCE...A WEAK SURFACE TROUGH OR COLD
FRONT MOVES TOWARD CENTRAL NORTH CAROLINA FROM THE NORTH LATE IN THE
WEEKEND. WITH THE BROAD SURFACE PATTERN MADE UP OF HIGH PRESSURE
FROM THE ATLANTIC INTO THE NORTHERN GULF...CONVERGENCE ALONG THE
FRONT IS EXPECTED TO BE WEAK. THE FLOW ALOFT SHOULD BE PREDOMINANTLY
NORTHWEST WITH PERIODIC SHORTWAVES IN THAT NORTHWEST FLOW. BOTH THE
GFS AND THE ECMWF SUGGEST THAT AN 850MB BOUNDARY MOVES SOUTH ACROSS
VIRGINIA AND IS LOCATED JUST NORTH OF THE STATE BY 12Z MONDAY. THIS
COULD HELP TO ENHANCE LOW-LEVEL CONVERGENCE SOMEWHAT...THOUGH GIVEN
THE RIDGING EXPECTED OVER THE GULF...VERY DEEP MOISTURE IS NOT
CURRENTLY ANTICIPATED.
MEAN RELATIVE HUMIDITY IS FORECAST TO INCREASE BY MONDAY...AND
COARSE MODEL SOUNDINGS ARE SUGGESTIVE OF AT LEAST AN INCREASE IN
CLOUDS BY THEN. SOME OF THE LONG-TERM GUIDANCE PRODUCES LIGHT QPF BY
MONDAY ESPECIALLY OVER NORTHERN PARTS OF THE STATE...CLOSER TO THE
850MB BOUNDARY THAT IS FORECAST BY MUCH OF THAT GUIDANCE. WITH
SURFACE AND 850MB RIDGING OVER THE GULF AND LIMITED SURFACE MOISTURE
RETURN...ANY RAINFALL THAT DEVELOPS IN MID-LEVEL LIFT NEAR WEAK
850MB AND SURFACE BOUNDARIES SHOULD BE LIGHT. FOR NOW...PLAN TO SHOW
AN INCREASE IN CLOUDS LATE IN THE HOLIDAY WEEKEND AND MAINTAIN THE
SLIGHT CHANCE OF SHOWERS MONDAY...CONTINUING THE SLIGHT CHANCE INTO
TUESDAY AS THE ORIENTATION OF ANY SURFACE BOUNDARY DOES NOT APPEAR
TO CHANGE MUCH FROM MONDAY INTO TUESDAY. MID-LEVEL HEIGHTS DO RISE
FROM MONDAY INTO TUESDAY...SO IN A RELATIVE SENSE THE CHANCES FOR
SHOWERS MAY END UP BEING A LITTLE HIGHER MONDAY COMPARED TO
TUESDAY...BUT GIVEN MANY MODEL RUNS BEFORE THE END OF NEXT WEEKEND
AND THE BROAD RIDGING IN PLACE OVER MUCH OF THE SOUTHEAST...WILL
MAINTAIN SIMPLY SLIGHT CHANCES FOR NOW. TEMPERATURES SHOULD AVERAGE
A CATEGORY OR TWO COOLER THAN NORMAL EARLY IN THIS PART OF THE
LONG-TERM PERIOD...CLOSER TO NORMAL TOWARD THE END OF THE PERIOD.
&&
.AVIATION /06Z WEDNESDAY THROUGH SATURDAY/...
AS OF 240 AM WEDNESDAY...
A CONTINUED VERY MOIST AIR MASS WILL RESULT IN A HIGH CHANCE OF
LIFR-IFR CEILINGS THIS MORNING. THESE CEILINGS WILL LIFT AND SCATTER
TO VFR WITH HEATING THROUGH MIDDAY. HEATING OF THE MOIST AIR MASS
WILL ALSO CAUSE WIDELY SCATTERED SHOWERS AND STORMS TO DEVELOP THIS
AFTERNOON...BUT WITH LESSER COVERAGE VERSUS PREVIOUS DAYS OWING TO
THE WEAKENING AND DEPARTURE OF A LIFT-INDUCING TROUGH THAT RESIDED
OVER THE AREA DURING RECENT DAYS. UNTIL A COLD FRONT SWEEPS
ACROSS CENTRAL NC THU NIGHT...THE CONTINUED VERY MOIST REGIME WILL
PROMOTE ADDITIONAL LOW STRATUS DEVELOPMENT TONIGHT...AND A CONTIUED
THREAT OF MAINLY AFTERNOON SHOWERS AND STORMS. VFR CONDITIONS WILL
OTHERWISE PREVAIL IN CANADIAN HIGH PRESSURE THROUGH THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...CBL
SHORT TERM...ELLIS
LONG TERM...DJF
AVIATION...MWS
| 
