Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 260841
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
441 AM EDT SAT JUL 26 2014

.SYNOPSIS...
HIGH PRESSURE SLIDES OFF THE MID ATLANTIC COAST TODAY AS A WARM
FRONT LIFTS NORTH ACROSS THE AREA THIS AFTERNOON THROUGH TONIGHT.
A STRONG COLD FRONT APPROACHES THE REGION ON SUNDAY AND CROSSES
THE AREA MONDAY INTO MONDAY NIGHT. STRONG TO SEVERE THUNDERSTORMS
WILL BE POSSIBLE SUNDAY AND MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE SFC COLD FRONT THAT BROUGHT SEVERE WX TO THE AREA ON THURSDAY
HAS WASHED OUT INTO A WARM FRONT AND IS EXPECTED TO SLOWLY LIFT
NWD ACROSS THE REGION THROUGH TODAY...FINALLY EXITING THE AREA
BY EARLY SUNDAY MORNING. MEANWHILE AS HIGH PRESSURE SLIDES OFF THE
COAST TODAY...DEWPOINTS WILL GRADUALLY RISE THROUGH THE DAY WITH
ONLY MINOR SUPPRESSION DURING AFTN MIXING AS WINDS BECOME S-SW AT
OR BELOW 10 MPH. TEMPERATURES WILL ALSO BE ON THE RISE WITH HIGHS
AROUND 90 INLAND AND IN THE MID-UPPER 80S ALONG THE COAST. A
SHORTWAVE PASSES JUST NORTH OF THE AREA LATE THIS MORNING THROUGH
THIS AFTN AND MAY KICK OFF A STRAY SHOWER/STORM OR TWO ACROSS FAR
NRN COUNTIES.

FOR TONIGHT...THE REGION BECOMES WELL-ROOTED IN THE WARM SECTOR
THIS EVENING AND DEWPOINTS AROUND 70 DEGREES WILL BE COMMON
AREAWIDE. A THERMAL/LEE SIDE TROUGH DEVELOPS IN THE WAKE OF THE
WARM FRONTAL PASSAGE OVERNIGHT...THUS CAUSING THE SFC PRESSURE
GRADIENT TO TIGHTEN AHEAD OF AN APPROACHING COLD FRONT FROM THE
WEST (S WINDS BTWN 5-10 MPH). A MUGGY NIGHT WILL BE ON TAP WITH
TEMPS/DEWPOINTS BOTH IN THE LOWER 70S. DESPITE CONDITIONS BEING
NEAR SATURATION...MIXING OVERNIGHT SHOULD PREVENT FOG FROM
DEVELOPING.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
THE THERMAL TROUGH STRENGTHENS ON SUNDAY AND THE SFC PRESSURE
GRADIENT TIGHTENS UP EVEN MORE AS A STRONG COLD FRONT APPROACHES
THE REGION FROM THE WEST. SHORTWAVE ENERGY EJECTS FROM A PARENT
LOW/TROUGH SWINGING THROUGH THE WRN GREAT LAKES ON SUNDAY IS
PROGGED TO CROSS NRN VA SUN AFTN/EVENING. CONFIDENCE IS INCREASING
REGARDING SEVERE WX POTENTIAL DURING THIS TIMEFRAME. NOT ONLY WILL
AMPLE MOISTURE BE PRESENT ACROSS THE REGION (PWATS AROUND 2.00
INCHES AND DEWPOINTS IN THE LOWER 70S) BUT 0-6KM BULK SHEAR
INCREASES TO 50-55 KT WITH INCREASING LEVELS OF 850-700MB MUCAPE
RANGING FROM 500-2500 J/KG...DEPENDING ON WHICH MODEL SOLUTION IS
PREFERRED. SFC LIFTED INDEX VALUES ARE ALSO VERY UNSTABLE (-3 TO
-7 DURING THE AFTN/EVENING). MODEL CROSS SECTIONS/TIME HEIGHTS
REVEAL PLENTY OF ELEVATED LIFT (INCLUDING THROUGH THE HAIL GROWTH
ZONE) AND SOUNDINGS CONFIRM THIS. SOUNDINGS ALSO SHOW INCREASING
WINDS WITH HEIGHT WITH DRY AIR ENTRAINMENT IN THE MID LEVELS (SW
SFC GUSTS TO AROUND 20 MPH IN THE AFTN). NAM SOUNDINGS SHOW THE WIND
PROFILE VEERING WITH HEIGHT WHILE THE GFS IS MORE UNIDIRECTIONAL.
ALL OF THE ABOVE CONVECTIVE PARAMETERS SUGGEST THAT ORGANIZED (AND
POSSIBLY LINEAR) CONVECTION WILL BE POSSIBLE ON SUNDAY. SOME
STORMS MAY BECOME SEVERE WITH DAMAGING WINDS...LARGE HAIL...AND
VERY HEAVY RAINFALL. SPC CONFIRMS THIS IN THEIR DAY 2 OUTLOOK
WHICH HAS THE ENTIRE WAKEFIELD CWA IN A SLIGHT RISK AREA FOR
DAMAGING WINDS AND LARGE HAIL. SUPERCELLS MAY ALSO BE POSSIBLE DUE
TO FAVORABLE SHEAR PROFILES...WHICH MEANS ISOLATED TORNADOES
CANNOT BE RULED OUT. WILL HIGHLIGHT SEVERE POTENTIAL IN THE HWO.
HIGH TEMPS OF 90-95 DEGREES ARE EXPECTED ON SUNDAY. THE
COMBINATION OF HEAT AND DEWPOINTS IN THE LOWER 70S WILL BUMP HEAT
INDEX VALUES TO 100-104 DEGREES (SUB-ADVISORY). IF THE AREA
EXPERIENCES MORE SUNSHINE EARLY IN THE DAY...ESPECIALLY SE VA/NE
NC...THEN HEAT INDICES COULD PUSH INTO ADVISORY LEVELS (105-109
DEGREES). WILL NEED TO MONITOR CLOSELY.

A BRIEF REPRIEVE FROM ADVERSE WX MAY BE POSSIBLE LATE SUNDAY NIGHT
INTO MONDAY MORNING PRE-FROPA. THE COLD FRONT IS EXPECTED TO GAIN
MOMENTUM FROM A STRONG SHORTWAVE SWINGING ACROSS THE OHIO VALLEY
INTO NEW ENGLAND DURING THE DAY. THIS SHOULD PUSH THE FRONT
QUICKLY THROUGH THE AREA MON AFTN/EVENING. THUNDERSTORMS ARE
EXPECTED TO BECOME FOCUSED ACROSS SE VA/NE NC DURING THE FRONTAL
PASSAGE. THE AFOREMENTIONED CONVECTIVE PARAMETERS FROM SUNDAY WILL
ALSO BE IN PLAY ON MONDAY. ALTHOUGH OVERALL VALUES ARE SLIGHTLY
WEAKER...THERE IS A CONTINUED THREAT FOR DAMAGING WINDS...LARGE
HAIL...AND VERY HEAVY RAINFALL. HIGH TEMPS WILL BE TRICKY DUE TO
EXACT PLACEMENT OF THUNDERSTORMS...HOW MUCH DRYING CAN OCCUR POST-
FRONTAL...AND HOW AFTN MIXING KEEPS TEMPS ELEVATED DUE TO BREEZY
SW-W WINDS WITH GUSTS TO AROUND 25 MPH. CURRENT FORECAST IS FOR
HIGHS IN THE LOWER 90S REGIONWIDE. A COOLER AND DRIER AIRMASS
FILTERS IN FROM THE NORTH MON NIGHT AS PRECIP COMES TO AN END
ACROSS THE SE. LOWS SHOULD RANGE FROM THE LOWER 60S NW TO LOWER
70S SE.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
GOING WITH A COMBINATION OF THE 12Z GFS AND 12Z ECMWF FOR THE
EXTENDED PERIOD. LONGWAVE TROF DIGS INTO AND OVR THE MID ATLC REGION
MON NGT INTO EARLY THU...BEFORE RETROGRADING BACK INTO THE OH AND MS
VALLEYS THU AFTN THRU FRI. COLD FRONT WILL PUSH OFF THE CST MON NGT
AND TUE...LINGERS FARTHER OFF THE CST TUE NGT THRU THU...THEN
POSSIBLY DRIFTS BACK TWD THE CST LATE FRI. OTHER THAN A SLGT OR SML
CHC FOR SHOWERS OVR EXTRM SE VA AND NE NC MON NGT INTO TUE
MORNG...WILL HAVE A DRY FCST FOR THE REMAINDER OF THE EXTENDED
PERIOD. A MORE COMFORTABLE AIRMASS WILL DOMINATE THE AREA TUE INTO
THU...BEFORE A LITTLE MORE HUMIDITY RETURNS ON FRI. MAX TEMPS WILL
GENERALLY BE IN THE LWR TO MID 80S THRU THE PERIOD. MIN TEMPS WILL
RANGE FM THE LWR 60S TO LWR 70S TUE MORNG...RANGE FM THE UPR 50S TO
MID 60S WED AND THU MORNGS...AND RANGE THRU THE 60S FRI MORNG.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
SFC HI PRES OFF THE CST...W/ LGT SSE WNDS ATTM. WNDS LIGHT
ENOUGH...AND RECENT RAINFALL PTNTLLY LEADING TO PTCHY FG (AND MVFR
CONDS) NEXT FEW HRS (THROUGH AT SUNRISE). XPCG SCT-BKN CLDNS
TDA...W/ LO PROB FOR ANY CONVECTION.

S-SW WINDS GUSTING TO 15 KT AND SCT-BKN CLDNS XPCD SUN AS A CDFNT
APPROACHES THE REGION FROM THE W. PTNTL FOR MVFR CONDS IN ANY SCT
CONVECTION LT MRNG THROUGH AFTN. THE FRONT IS EXPECTED TO CROSS
THE REGION ON MONDAY.

NOTE: OBSERVATIONS FROM KSBY ARE NOT READILY AVAILABLE DUE TO A
COMMUNICATIONS PROBLEM. RETURN TO SERVICE IS UNKNOWN AT THIS TIME.
HOWEVER...CURRENT INFORMATION MAY BE OBTAINED BY CALLING INTO THE
ASOS SITE DIRECTLY. AMD NOT SKED WILL BE APPENDED TO THE KSBY TAF
UNTIL FURTHER NOTICE.

&&

.MARINE...
NO HEADLINES XPCD THROUGH MON. HI PRES SLIDES E OF THE WTRS THROUGH
TNGT. S TO SW WINDS WILL AOB 15 KT TDA...INCRS A BIT TNGT...ESP ON
THE OCN (TO ABT 20 KT). IN ADVANCE OF APPROACHING CDFNT...SIMILAR
CONDS (SSW WNDS AVGG SPEEDS AOB 15 KT) SUN THROUGH MON. THAT CDFNT
TO CROSS THE WTRS MON...THEN OFF THE CST MON NGT. WNDS WILL TURN
TO THE NW BEHIND THE FNT INTO TUE (W/ A PSBL SURGE IN SPEEDS).

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BMD
NEAR TERM...BMD
SHORT TERM...BMD
LONG TERM...TMG
AVIATION...ALB
MARINE...ALB








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