National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 181438
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1038 AM EDT SAT MAY 18 2013

.SYNOPSIS...
-- Changed Discussion --
A WEAK FRONT REMAINS NEARLY STATIONARY OVER SOUTHWEST VIRGINIA AND
NORTH CAROLINA THROUGH SATURDAY NIGHT. THE FRONT WILL SLOWLY LIFT
BACK TO THE NORTH LATER SUNDAY INTO MONDAY.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
10 AM UPDATE...A PERSISTENT AREA OF SHOWERS CONTINUES ACROSS
NORTHERN PORTIONS OF THE FA NORTH OF RICHMOND AND EAST TO THE LOWER
EASTERN SHORE. MOST SURFACE WINDS WERE FROM THE E WITH SOUTHERLY
WINDS A FEW THOUSAND FEET PER AKQ VAD WIND AND RAOB FROM WAL AND
LWX. THIS INDICATES LOW LEVEL ADVECTION OF MOISTURE AND WARM AIR
WILL CONTINUE DESPITE RELATIVELY COOL TEMPERATURES AT THE SURFACE.

A FRONT EXTENDS FROM THE OHIO VALLEY TO NORTHEAST NORTH CAROLINA.
WHERE THIS CROSSES VA/WV IS NOT WELL DEFINED. THE FRONT OVER
NORTHEAST NORTH CAROLINA EXTENDS EAST-WEST JUST SOUTH OF THE
ALBEMARLE SOUND. THIS WILL LIKELY BE A FOCUS FOR MIDDAY/EARLY AFTN
SHOWERS. THAT MAY AFFECT COUNTIES NORTH OF THE ALBEMARLE. OTHER
SHOWER AND THUNDERSTORM ACTIVITY IS INDICATED THIS AFTN FOR SOUTH
CENTRAL VA AND PIEDMONT COUNTIES. HAVE LIKELY POPS FOR THIS AREA AFT
19Z. REST OF THE CWA HAS CHC POPS THE REST OF THE DAY.

ANY SHOWER AND THUNDERSTORM ACTIVITY THIS AFTN WILL BE CAPABLE OF
PRODUCING HEAVY DOWNPOURS WITH PRECIPITABLE WATER VALUES AROUND 1.5
INCHES WHICH IS WELL ABOVE NORMAL.

HIGH TEMPERATURES WILL BE AFFECTED BY BREAKS IN THE OVERCAST WHICH
WILL BE MOST ABUNDANT OVER SOUTHERN PORTIONS. HAVE MAX READINGS FROM
AROUND 70 ON THE LOWER ERN SHORE AND LOW TO MID 70S N OF INTERSTATE
64 TO AROUND 80 ALONG OUR SRN BORDER.

TONIGHT...SHOWER AND TSTM ACTIVITY IS EXPECTED TO INCREASE ACROSS
THE AREA AS THE UPR LOW OVER THE TENNESSEE VALLEY MOVES SLOWLY TO
THE EAST. WAA WILL CONTINUE TO INCREASE AND PCPN WILL LIKELY FOCUS
OVER NRN PORTIONS OF THE AREA AND ONTO THE LOWER EASTERN SHORE. LOW
TEMPERATURES WILL BE GENERALLY IN THE LOW TO MID 60S WITH UPR 50S
ON THE MD EASTERN SHORE.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
WET WEATHER WILL CONTINUE THROUGH THE SHORT TERM AS THE STALLED
FRONT BEGINS TO LIFT NWD AS A WARM FRONT SUN AND MON. MAIN
FORECAST CHALLENGES WILL BE TIED TO PRECIP COVERAGE AND QPF.

WEAKENING UPPER LOW EXPECTED TO MEANDER IN THE VICINITY OF THE
CUMBERLAND PLATEAU SUNDAY. POTENT TROUGH TRAVERSING THE PLAINS SUN
WILL AMPLIFY THE RIDGE OVER THE ERN CONUS...HELPING LIFT THE
STALLED BOUNDARY NWD AS A WARM FRONT LATE SAT NIGHT AND SUN. AT
THE SAME TIME...INCREASING SW FLOW (H85 WINDS 20-30 KT) WILL
ADVECT NEARLY +2 STD DEV PRECIP WATER VALUES INTO THE REGION.
ADDITIONAL WEAK IMPULSES WILL EJECT EWD FROM THE UPPER
LOW...COMBINING WITH ABUNDANT MOISTURE FOR ADDITIONAL SHOWERS AND
THUNDERSTORMS DURING THE AFTERNOON AND EVENING SUN. THETA-E
ADVECTION AND TEMPS IN THE UPPER 70S/LOW 80S WILL MAINTAIN A
MARGINALLY UNSTABLE AIRMASS (500-1000 J/KG CAPE) OVER SRN
VA...RESULTING IN A GOOD CHANCE FOR AFTERNOON THUNDERSTORMS.
COMBINATION OF CONVECTION AND DEEP MOISTURE COULD LEAD TO A THREAT
OF FLASH FLOODING...ESPECIALLY IF WIDESPREAD RAINFALL OCCURS THIS
AFTERNOON (SAT AFTERNOON).

MIDWEST TROUGH WILL KICK WHATS LEFT OF THE UPPER LOW EWD MONDAY OVER
THE APPALACHIANS...LOCATING OVER THE FA MONDAY. MEANWHILE...THE
WARM FRONT WILL LIFT NORTH OF THE FA. ABUNDANT MOISTURE AND GOOD
DYNAMICS WILL RESULT IN ADDITIONAL SHOWERS AND THUNDERSTORMS.
WARMER TEMPS WILL RESULT IN GREATER INSTABILITY...WITH ADDITIONAL
ROUNDS OF HEAVY RAIN POSSIBLE.

72 HR QPF TOTALS FORECAST TO RANGE FROM OVER 2 INCHES ACROSS THE
PIEDMONT TO JUST OVER HALF AN INCH FOR THE MD ERN SHORE. SE VA/NE
NC COULD SEE TOTALS UPWARDS OF ONE INCH. IN ADDITION TO THE FLASH
FLOOD THREAT...SEVERAL ROUNDS OF RAINFALL OVER THE REGION MAY LEAD
TO RIVER FLOODING CONCERNS.

HI TEMPS WILL GENERALLY RANGE FROM THE LOW/MID 70S NORTH TO LOW
80S SOUTH (NEAR SEASONABLE NORMS) SUN. COOLER ALONG THE IMMEDIATE
COAST. WARMER MONDAY WITH HIGHS GENERALLY IN THE LOW 80S.
AGAIN...COOLER ALONG THE IMMEDIATE COAST.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
LONG TERM PERIOD WILL FEATURE PERIODS OF UNSETTLED WX AND ABOVE
NORMAL HI/LO TEMPS ON AVG. FOR TUE...MID-LVL S/W TROF PUSHES
OFFSHORE ERLY IN THE DAY WITH A CHC FOR SHWRS MAINLY OVER SE AREAS.
DECREASING CLDS DURING THE AFTN WITH TEMPS CLIMBING INTO THE MID
80S. S/SW FLOW CONTINUES WED AND THU LEADING TO CONTINUED WARM TEMPS
(HIGHS IN THE MID TO UPR 80S) AND A CHC FOR MAINLY DIURNAL SHWRS/TSTMS
WITH WEAK SFC TROFS OVER THE AREA. BEST CHC FOR RAIN WILL BE FRI AS
A COLD FRNT ADVANCES TOWARDS THE AREA. WILL CAP POPS AT 40% FOR
NOW WITH HOW FAR OUT IN TIME THIS IS ALBEIT FAIRLY GOOD
CONSISTENCY AMONGST MODEL GUIDANCE WITH THE FRNTAL TIMING. HI
TEMPS ONLY IN THE UPR 70S TO NEAR 80 FRI DUE TO PRECIP AND
WIDESPREAD CLOUDINESS.

&&

.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
THE AREA OF SHOWERS WHICH MOVED ACROSS CENTRAL VA...TIDEWATER AND
NC NC ARE PUSHING OFFSHORE. ONLY A FEW STRAY SHOWERS ARE EXPECTED
THROUGH THE MORNING HOURS AND VSBYS SHOULD REMAIN 5SM OR BETTER
IN ANY LIGHT SHOWERS. CEILING THIS MORNING WILL BE A MIX OF MVFR
AND VFR. BY MID TO LATE MORNING EXPECT MOST LOCATION TO IMPROVE TO
VFR WITH CEILINGS AOB 3KFT. THIS MAY BE SHORT LIVED FOR A PERIOD
LATE THIS MORNING AND EARLY AFTERNOON AS A A WEAK WARM FRONT WILL
SLOWLY LIFT SW- NE ACROSS THE REGION TODAY INTO TONIGHT. ADDITIONAL
SCT SHRA/TSRA WILL DEVELOP THIS AFTERNOON WITH INCREASING SELY
FLOW. SHOWERS WILL INCREASE IN COVERAGE THROUGH THE AFTERNOON AND EVENING.
VFR CONDITIONS SHOULD GENERALLY PREVAIL LATE THIS MORNING INTO
EARLY AFTERNOON WITH THE EXCEPTION OF REDUCED VSBY IN MODERATE
SHOWERS WHICH START TO DEVELOP AROUND 17-19Z. STATISTICAL
GUIDANCE ALONG WITH FORECAST SOUNDINGS SUGGEST THE POTENTIAL FOR
IFR STRATUS LATER TONIGHT...ESPECIALLY FOR RIC/PHF/SBY. THE
POTENTIAL FOR SHRA/TSRA CONTINUES SUNDAY INTO EARLY NEXT WEEK AS
MOIST SE TO SW FLOW CONTINUES TO AFFECT THE REGION.

&&

.MARINE...
A WEAK FRONTAL BOUNDARY ACROSS THE REGION IS BEGINNING TO SLOWLY
LIFT NE AS A WARM FRONT EARLY THIS MORNING. THIS SLOW PROCESS IS
EXPECTED TO CONTINUE THROUGH THE DAY INTO TONIGHT. MEANWHILE...HIGH
PRESSURE WILL REMAIN ANCHORED OFF CAPE COD AS TROUGH OF LOW PRESSURE
APPROACHES FROM THE WEST. THIS WILL RESULT IN A TIGHTENING PRESSURE
GRADIENT ACROSS THE REGION LATER THIS AFTERNOON INTO TONIGHT. A
10-15KT ESE WIND IS EXPECTED TO APPROACH 20KT LATER THIS AFTERNOON
THROUGH THIS EVENING FOR THE BAY/LOWER JAMES. SIMILAR SPEEDS ARE
EXPECTED FOR THE OCEAN. HOWEVER...THE ONSHORE COMPONENT TO THE WIND
SHOULD ALLOW SEAS TO BUILD TO 5FT LATER TODAY INTO TONIGHT...MAINLY
N OF CAPE CHARLES. HENCE SCA FLAGS HAVE BEEN RAISED FOR THE
AFOREMENTIONED AREAS BEGINNING AT 20Z/4PM THIS AFTERNOON AND
CONTINUING THROUGH 04Z/12AM FOR THE BAY/LOWER JAMES AND 10Z/6AM FOR
THE OCEAN. THE WARM FRONT FINALLY CLEARS THE REGION LATER SUNDAY
AFTN/EVE ALLOWING FOR THE WIND TO SHIFT TO S AND EVENTUALLY SW.
SPEEDS SHOULD GENERALLY REMAIN AOB 15KT. HOWEVER...A BRIEF INCREASE
IS POSSIBLE MONDAY AFTN/EVE AS LOW PRESSURE TRACKS N OF THE REGION.
SEAS SHOULD LARGELY BE 3-4FT WITH ~2FT WAVES.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT EDT
     TONIGHT FOR ANZ630>632-634-638.
     SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EDT
     SUNDAY FOR ANZ650-652-654.

&&

$$
SYNOPSIS...LKB/LSA
NEAR TERM...SAM/LSA
SHORT TERM...SAM
LONG TERM...MAS
AVIATION...AJZ/JAO
MARINE...AJZ