Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 300758
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
358 AM EDT SAT AUG 30 2014

.SYNOPSIS...

HIGH PRESSURE OFF CAPE COD WILL MOVE SOUTHEAST AND BECOME A
BERMUDA HIGH FOR THE HOLIDAY WEEKEND AND THROUGH TUESDAY. A COLD
FRONT WILL CROSS THE AREA TUESDAY NIGHT. HIGH PRESSURE WILL FOLLOW
FOR THE SECOND HALF OF THE WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

TEMPERATURES AND HUMIDITY WILL BE REBOUNDING TODAY AS HIGH
PRESSURE SLIPS OFFSHORE. ANY ISOLATED TSTMS TODAY WILL BE OVER
WEST CENTRAL VA AND EASTERN WV. CLOUD COVER WILL BE TRICKY TODAY
AS THERE IS A DECENT SHIELD OF 5000FT CEILINGS OVER A LARGE PART
OF THE FORECAST AREA EARLY THIS MORNING. ALL IN ALL PARTLY OR
VARIABLY CLOUDY FOR MOST TODAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...

SAT NIGHT HUMIDITY INCREASES...WEAK SHORT WAVE MOVES OVERHEAD AND
LEE TROF BEGINS TO ASSERT ITSELF. ALL OF THAT SHOULD ALLOW FOR
ISOLATED STORMS EAST OF THE BLUE RIDGE OVERNIGHT WITH SCATTERED
STORMS TO THE WEST.

SUNDAY FEATURES THE BEST CHANCE OF STORMS OVER THE HOLIDAY WEEKEND
RIGHT NOW. LEE TROF IN PLACE...WEAK SHORT WAVE MOVING IN...HI TEMPS
IN THE MID 80S TO AROUND 90...SOME WEAK JET DIVERGENCE AT HIGHER
LEVELS...ALL OF THESE ARE INGREDIENTS FOR SOME STORMS. THE MOST
DISTURBING PARAMETER IS THE GFS FORECASTING PRECIPITABLE WATER TO
BE OVER 2 INCHES OVER A WIDE AREA. WHILE THERE IS ENOUGH WIND IN
THE ATMOSPHERE TO KEEP STORMS MOVING...COULD BE ISOLATED AREAS OF
FLASH FLOODING WITH THAT MUCH MOISTURE. WILL MAINTAIN MENTION IN
HAZARDOUS WEATHER OUTLOOK FOR SUNDAY INTO SUNDAY NIGHT.

MONDAY WILL STILL BE WARM AND HUMID...BUT PRECIPITABLE WATERS
FALL...LEE TROF SLACKENS...AND SHORT WAVE MOVES OUT. FOR THESE
REASONS EXPECT LESSER CHANCES OF STORMS MONDAY THAN SUNDAY FOR ANY
ONE SPOT. STILL SCT STORMS EXPECTED THOUGH.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...

ELEVATED HEAT INDICES WILL CONTINUE TO BE A CONCERN HEADING INTO
MIDDLE OF NEXT WEEK. DEWPOINTS WILL CONTINUE HOVERING AROUND THE 70F
DEG MARK...WHICH IS PLENTY HUMID IN COMBINATION W/ DAILY HIGHS
POKING ABOVE 90F DEG. FROM LATE MON INTO TUE...A POTENT AND LARGE-
SCALE LOW PRESSURE SYSTEM WILL SWINGING THRU THE GREAT LAKES/UPPER
MIDWEST. THE PARENT LOW WILL BE WELL TO THE NORTH...PULLING UP INTO
THE SRN HUDSON BAY REGION/QUEBEC. THE DYNAMICS OF THIS SYSTEM WILL
HEAD DUE EAST...STRADDLING THE US/CANADA BORDER AND TAKING THE
HEAVIEST PRECIP ALONG W/ IT - WELL TO OUR NORTH TUE INTO WED.

SOME RESIDUAL SHOWERS HANGING AROUND THE COASTAL ZONES OVER TO THE
I-95 CORRIDOR FROM LATE MON NIGHT WILL BE DISSIPATING EARLY TUE...AS
HIGH PRES BUILDS IN FROM THE SRN APLCNS. THIS HIGH...IN CONCERT W/
THE OFFSHORE AND LARGER BERMUDA HIGH WILL AGAIN PRESS THE
HEAT/HUMIDITY UP INTO THE MID ATLC. THE RELATIVE LACK OF ORGANIZED
FORCING ACROSS THE REGION WILL KEEP SKIES GENERALLY CLEAR TUE WHICH
WILL BE LITTLE RELIEF IN TERMS OF THE HOT CONDITIONS. MORE DRY AND
HOT WEATHER TO CARRY US THRU THE SECOND HALF OF THE WEEK...THOUGH
TUE MAY BE THE WARMEST DAY - ALBEIT ONLY BY COUPLE OF DEG. LATE TUE
EVE...THE TAIL END OF THE COLD FRONT FROM THE GREAT LAKES LOW WILL
LIKELY CROSS THE REGION. THE FRONT WILL CARRY SOME SCATTERED SHOWERS
AND TSTMS. GOOD LOW LEVEL LAPSE RATES DURING PEAK HEATING AND MODEST
INSTABILITY WILL MAKE FOR AT LEAST A HANDFUL OF STRONG TSTMS...MORE
IF OUTFLOW-DRIVEN.

ZONAL UPPER FLOW OVER THE NRN HALF OF THE CONUS FOR THE SECOND HALF
OF WEEK WILL ESSENTIALLY HOLD OUR WARM/HUMID AIRMASS IN PLACE. WHILE
THE COLD FRONT KICKS OFF PRECIP A COUPLE OF STATES TO OUR
SOUTH...THE MID-ATLC WILL BE MAINLY DRY TO CLOSE OUT THE WEEK UNTIL
AN UPPER SHORTWAVE ARRIVES FROM THE WEST LIKELY NEXT WEEKEND.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...

WITH INCREASING LOW LVL HUMIDITY...OVERNIGHT FOG WILL BE AN
INCREASING ISSUE THRU THE WEEKEND. EXPECT SOME LIGHT FOG AT CHO
TONIGHT...THEN 3-5SM FOG FOR DULLES AND AREAS WEST TOMORROW NIGHT.
ALSO TARGETED IFR POSSIBLE AT TIMES WITH ANY THUNDERSTORMS.

HOT/HUMID AIRMASS STAYS IN PLACE FOR THE NEXT SEVERAL DAYS. TUE MAY
BE THE WARMEST DAY OF THE STRETCH BUT NOT BY MUCH. DAILY HIGHS IN
THE U90S AND DEWPOINTS HAVING HUMID FOR THIS TIME OF YEAR. ONLY
BRIEF AND SHORT-LIVED PERIODS OF PRECIP POSSIBLE INTO MID NEXT
WEEK...BUT MAINLY DRY AND MOSTLY SUNNY EACH DAY.

&&

.MARINE...

WILL HAVE TO MONITOR CENTRAL AND SOUTHERN MD CHES BAY FOR SMALL
CRAFT GUSTS LATE TODAY AND TONIGHT...AND THEN AGAIN LATE SUNDAY
INTO SUN EVENING. IT WILL BE BORDERLINE.

OFFSHORE HIGH PRES WILL CONTINUE TO STEER WARM/HUMID AIR UP ACROSS
THE ERN SEABOARD. ONLY MINOR PERIODS OF SLY CHANNELING AND/OR SCA
CONDITIONS POSSIBLE INTO THE MIDDLE OF NEXT WEEK. A WEAK COLD FRONT
WILL LIKELY CROSS THE WATERS BY LATE TUE/EARLY WED. A FEW TSTMS
POSSIBLE W/ THIS FEATURE. HIGH PRES THEN BUILDS IN THROUGH THE REST
OF THE WEEK.

&&

.COASTAL FLOODING...

WITH SOUTHEAST WINDS BECOMING S...AND NOT TOO FAR FROM NEW
MOON...CONTINUE TO MONITOR THE SLOWLY INCREASING TIDAL ANOMALY.
NOT ANY TROUBLE YET...BUT COULD BE IN THE MOST SENSITIVE SPOTS
LIKE ANNAPOLIS WITHIN 24 HRS.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY 4 PM SATURDAY UNTIL 4 AM SUNDAY FOR
         ANZ533-534.

&&

$$
SYNOPSIS...CAS
NEAR TERM...CAS
SHORT TERM...CAS
LONG TERM...CAS/GMS
AVIATION...CAS/GMS
MARINE...CAS/GMS
COASTAL FLOOD...CAS




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