Area Forecast Discussion
Issued by NWS Wakefield, VA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS61 KAKQ 240656
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
256 AM EDT FRI APR 24 2015

.SYNOPSIS...
CANADIAN HIGH PRESSURE SLOWLY BUILDS INTO THE REGION THROUGH
FRIDAY. A WARM FRONT LIFTS INTO THE CAROLINAS ON SATURDAY AS LOW
PRESSURE APPROACHES FROM THE WEST. LOW PRESSURE CROSSES THE REGION
SATURDAY NIGHT...PUSHING OFFSHORE SUNDAY. HIGH PRESSURE RETURNS
EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A SHORTWAVE TROUGH ROUNDS THE BASE OF AN UPPER LOW AS IT DROPS
INTO THE NRN MID-ATLANTIC REGION TONIGHT. SOME MODELS ATTEMPT TO
SQUEEZE OUT SOME PRECIP...BUT DRY LOW LEVELS AND PWATS AOB
0.30 INCHES WILL PREVENT ANYTHING MORE THAN MID LEVEL CLOUDS.
WHILE DEWPOINTS WILL REMAIN LOW...LIGHT MIXING AND A PARTLY CLOUDY
SKY WILL PREVENT THE BOTTOM FROM DROPPING OUT OF THE TEMPS. LOWS
PROGGED TO BE IN THE MID-UPPER 30S INTERIOR VA/NC AND UPPER
30S-LOW 40S NEAR THE COAST. SOME LOW-LYING RURAL LOCALES MAY DROP
TO NEAR FREEZING...BUT DRY CONDITIONS AND LIGHT MIXING WILL LIKELY
INHIBIT FROST FROM DEVELOPING.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
SHORTWAVE ENERGY SLIDES OFF THE DELMARVA COAST FRI
MORNING...RESULTING IN NWLY FLOW ALOFT OVER THE MID ATLANTIC.
CONFLUENCE ALOFT WILL ALLOW COOL/CANADIAN HIGH PRESSURE TO BUILD
EWD...LOCATING OVER THE REGION LATE FRI. THE RESULT WILL BE ANOTHER
DAY OF DRY CONDITIONS AND BELOW NORMAL TEMPS. H85 TEMPS BTWN -2C AND
+2C (-1 STD DEV) AND THICKNESSES YIELD TEMPS IN THE MID 60S INLAND
AND UPPER 50S TO LOW 60S ERN SHORE AND COASTAL AREAS (-1 STD DEV).
NOT AS BREEZY...WITH GUSTS OF 20 TO 25 MPH ACROSS THE N AND NE.

MID-LEVEL RIDGE AXIS LOCATES FROM THE OH VALLEY TO THE SE COASTAL
PLAINS SAT NIGHT AS SFC HIGH PRESSURE PUSHES OFFSHORE. MID LEVEL
MOISTURE RETURN IN ADVANCE OF AN APPROACHING LOW PRESSURE SYSTEM
WILL RESULT IN INCREASING MID-UPPER CLOUDS LATE SAT NIGHT. NOT AS
COLD...WITH LOWS IN THE UPPER 30S N TO MID 40S SOUTH. INTERIOR MD
ERN SHORE LOCALES COULD DROP INTO THE MID 30S...WHERE SKIES WILL
REMAIN MOSTLY CLEAR. SHORTWAVE ENERGY DEAMPLIFIES AS IT MOVES INTO
THE OH/TN VALLEYS SAT. ASSOCIATED SFC LOW LOCATES OVER THE OH
VALLEY. INCREASING/AMPLIFYING FLOW OVER THE SE CONUS WILL LIFT THE
STALLED BOUNDARY OVER THE GULF STATES NWD AS A WARM FRONT. MOISTURE
ALSO RETURNS IN EARNEST LATE SAT...COINCIDING WITH BEST ISENTROPIC
LIFT. EXPECT RAIN TO SPREAD OVER THE PIEDMONT INTO CNTRL/ERN VA SAT
AFTERNOON. POPS REMAIN LIKELY OVER THE AREA...EXCEPT CHANCE OVER THE
MD ERN SHORE. BETTER LIFT FROM THE WEAKENING SHORTWAVE ARRIVES SAT
NIGHT. SRN STREAM ENERGY LIFTING FROM THE GULF STATES SAT NIGHT WILL
LIKELY DEVELOP A WAVE OF LOW PRESSURE ALONG THE LIFTING WARM FRONT
AS THE ORIGINAL LOW WEAKENS OVER THE OH VALLEY. TRENDED FORECAST
AWAY FROM THE 23/12Z GFS AS IT KEEPS THE INLAND LOW MUCH STRONGER
THAN THE COASTAL LOW. THIS DOESNT MATCH PV AND THETA-E FIELDS...AS
THEY WOULD FAVOR COASTAL LOW DEVELOPMENT. THUS TRENDED FORECAST
TOWARD 23/15Z SREF AND 23/12Z ECMWF GUIDANCE. THIS SOLUTIONS PUTS
THE BEST LIFT ALONG THE INTERSTATE 64 CORRIDOR SUNDAY MORNING AS THE
INLAND SFC LOW DISSIPATES. COASTAL LOW STRENGTHENS...WITH CHANCES
FOR LIGHT RAIN CONTINUING THRU SUN MORNING. BEST CHANCES WILL THEN
TRANSFER TO THE COAST (ERN VA/NE NC) SUN AFTERNOON. LIFT IS RATHER
MODEST...ALONG WITH PWATS ONLY AROUND 1 INCH ACROSS THE REGION.
THUS...EXPECT ONLY LIGHT TO MODERATE RAIN WITH RAINFALL AMOUNTS
GENERALLY BTWN ONE QUARTER AND ONE HALF INCH (HIGHEST IN THE SOUTH).

COOL/DAMP/CLOUDY CONDITIONS WILL RESULT IN HIGHS IN THE MID-UPPER
50S (-1 TO -1.5 STD DEV) SAT AND LOWS IN THE MID 40S TO LOW 50S SAT
NIGHT. CLOUDY SKIES PERSIST SUN WITH HIGHS IN THE LOW 60S.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MEDIUM RANGE PERIOD BEGINS WITH AN UPPER LOW CENTERED
FROM ERN NY STATE INTO NEW ENGLAND AND WEAK UPPER LEVEL RIDGING OVER
THE LOWER MS VALLEY. ANOTHER UPPER LOW IN PLACE ACRS THE SW CONUS.
OVERALL...THIS SOMEWHAT "BLOCKY" PATTERN WILL MAKE FOR SLOW MOVEMENT
OF UPPER LEVEL FEATURES THROUGH THE MIDDLE OF NEXT WEEK. THE UPPER
LOW TO OUR NE LOOKS TO BE THE STRONGEST FEATURE...AND GFS/ECMWF IN
GOOD AGREEMENT THAT ANOTHER SHORTWAVE WILL ROTATE AROUND THE BASE OF
THIS TROUGH/UPPER LOW ON MON. LOCAL AREA WILL BE ON BACKSIDE OF THE
UPPER LOW SUN NIGHT/MON SO A DRYING TREND WILL COMMENCE.
TEMPERATURES MON LOOK TO REMAIN COOLER THAN AVG WITH HIGHS MAINLY IN
THE 60S AFTER AM LOWS IN THE 40S TO AROUND 50 F. WILL CARRY A 20%
POP ACRS THE MD ERN SHORE AS THIS AREA WILL BE NE OF THE TRACK OF
THE SHORTWAVE. SKIES AVG PARTLY SUNNY MOST AREAS...TRENDING TO
MOSTLY CLOUDY IN THE NE. AS UPPER RIDGING OVER THE WRN CONUS SHIFTS
NE FROM THE NRN ROCKIES TO THE NRN PLAINS LATER TUE/WED...THE UPPER
LOW WILL GRADUALLY WEAKEN/SHIFT OFF THE EAST COAST. MID ATLC REGION
LOOKS TO BE LOCATED IN BETWEEN SYSTEMS TUE INTO EARLY WED WITH WEAK
SFC HIGH PRESSURE OVER THE AREA. WILL HAVE DRY CONDITIONS AND PARTLY
/MOSTLY SUNNY SKIES. REMAINING COOL WITH HIGHS GENLY REMAINING IN
THE 60S...PERHAPS ONLY THE UPPER 50S AT THE ATLC COAST. LOWS AVG IN
THE UPPER 30S TO MID 40S.

EXPECT INCREASING SW FLOW ALOFT LATER WED INTO THU...BRINGING
OVERRUNNING AND A CHANCE FOR PRECIP STARTING LATER WED AND LASTING
INTO THU. GFS/ECMWF NOW DEVELOP A COASTAL SFC LOW BY THU. HAVE POPS
IN THE 30-40% RANGE FROM LATER WED THROUGH THU ALTHOUGH STILL A LOT
OF UNCERTAINTY AS THIS IS LATE DAY6/DAY 7. HIGHS IN THE UPPER 50S TO
THE 60S AND LOWS IN THE UPPER 40S TO THE 50S.

&&

.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
DRY/VFR CONDS WILL CONTINUE INTO SAT AS HIGH PRESSURE BUILDS IN
FROM THE WNW. GUSTY WINDS (TO MNLY 20-25 KT...A BIT HIGHER PSBL
INVOF KSBY) AGAIN INTO MID/LT THIS AFTN. DIMINISHING WNDS FOR TNGT
AND SAT WHILE BECOMING ONSHORE. GOOD CHANCE FOR LWRG CIGS/VSBYS
AND RAIN LATER SAT INTO SUNDAY. IMPROVING CONDITIONS LATE SUN
THROUGH MON.

&&

.MARINE...
PD OF LO LVL CAA XPCD INTO THE LT MRNG HRS BEFORE WANING THIS
AFTN...RESULTING IN NNW WNDS TO SCA (NR 20 KT ON THE BAY/SND...20
TO 25 KT ON THE MUCH OF THE OCN).

HIGH PRES SLOWLY BUILDS OVR THE WATERS THROUGH TNGT (W/ CONDS
FALLING BELOW SCA SOME TIME IN THE AFTERNOON/EVE). SUB-SCA MARINE
CONDITIONS PREVAIL TNGT THROUGH SAT W/ WITH WEAK HIGH PRESSURE
OVER THE AREA. A WEAK SFC LOW DEVELOPS OVER THE OHO RIVER VALLEY
AND PASSES ACROSS VA AND OFFSHORE SUNDAY. VARIABLE WINDS SUNDAY
BECOME NNW SUN AFTN/EVE W/ SPEEDS INCRSG TO PSBL SCA...ESP
CNTRL/SRN OCN WATERS...AND NR THE LWR BAY...AS THE LOW MOVES
OFFSHORE. THOSE ENHANCED WNDS CONT SUN NGT BEFORE WANING EARLY
NEXT WK.

&&

.FIRE WEATHER...
COOL DRY AIRMASS REMAINS OVER THE REGION FRI. MINIMUM RH VALUES
ARE FORECAST TO RANGE FROM 20-30 PCT...WITH NWLY WINDS 10-15 MPH
WITH GUSTS OF 20-25 MPH. STRONGEST GUSTS EXPECTED ACROSS THE NRN
NECK AND ERN SHORE. FUELS HAVE HAD ANOTHER DAY TO DRY...BUT STILL
REMAIN MARGINAL. NO HEADLINES ARE PLANNED ATTM AS SPS STILL
REMAINS OUT FOR MD ERN SHORE. WILL READDRESS TONIGHT. RECENT
RAINFALL AND GREEN-UP CONTINUE TO BE LIMITING FACTORS. LIGHT WINDS
AND INCREASING MOISTURE SAT WILL NEGATE FIRE WEATHER CONCERNS.
WIDESPREAD RAINFALL IS EXPECTED SAT AFTERNOON THRU SUN.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ630>634-638-
     650-652-654-656-658.

&&

$$
SYNOPSIS...MAS/SAM
NEAR TERM...MAS/SAM
SHORT TERM...MAS/SAM
LONG TERM...LKB
AVIATION...ALB/LKB/JEF
MARINE...ALB/LKB
FIRE WEATHER...AKQ


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.