Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 301906
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
306 PM EDT THU JUL 30 2015

.SYNOPSIS...
A COLD FRONT MOVES THROUGH LATE TODAY...WITH HIGH PRESSURE
BUILDING IN THE WAKE. A COLD FRONT MAY MOVE THROUGH OVER THE
WEEKEND...WITH THE HIGH PRESSURE RETURNING TO START THE WEEK
BEFORE THE NEXT COLD FRONT MOVES THROUGH THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
PRE-FRONTAL LINE OF THUNDERSTORMS EXTENDING FROM CECIL COUNTY
SOUTHWEST INTO CENTRAL VA AS OF 1830Z REFLECTIVITY. SPC
MESOANALYSIS SHOWING SBCAPE ANYWHERE FROM 1500-2500 J/KG EAST OF
THE BLUE RIDGE AFTR A DAY OF TEMPS REACHING THE UPPER 80S AND DEW
PTS HOVERING IN THE MID 70S. EXPECTING THIS LINE TO HOLD TOGETHER
AS IT MOVES INTO A VERY UNSTABLE AIR MASS...THOUGH WITH LACK OF
SHEAR AND WEAK LAPSE RATES ANY FURTHER SVR WX LOOKS TO BE MINIMAL.

SFC ANALYSIS SHOWING COLD FRONT OVER WESTERN VA/EASTERN WV AND
WILL SWING THROUGH LATE THIS AFTN INTO THIS EVENING. MODELS
SUGGESTING ANOTHER ROUND OF PCPN WILL BE PSBL ALONG THE
FRONT...ESP OVER THE PIEDMONT AND SOUTH AS THIS AREA HAS YET TO BE
TAPPED. THE TIME FRAME FOR THIS LOOKS TO BE 21-02Z.

THE FRONT THEN PUSHES THRU...WITH CLEARING IN THE WAKE. TEMPS
MILDLY DECREASE...WITH THE FRONTAL PASSAGE BEING MORE NOTICABLE IN
THE DEW PTS AS THEY DROP INTO THE 50S AND 60S. HIGH PRESSURE
BUILDS IN...KEEPING THE AREA DRY THEN THRU FRI NIGHT.

LOWS TONIGHT NEAR NORMAL. PLENTY OF WARMING UNDER MOSTLY SUNNY
SKIES AND DOWNSLOPING FROM WLY FLOW ON FRI COULD PUSH TEMPS INTO
THE UPPER 80S...TOUCHING 90 IN THE DC AND BALTIMORE METRO AREAS.
HOWEVER...WITH THE LOWER DEW PTS...HEAT ADVISORY CRITERIA IS NOT
EXPECTED TO BE REACHED.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE MID ATLANTIC REMAINS UNDER A BROAD UPPER LVL TROUGH AND ON
THE WESTERN PERIPHERY OF HIGH PRESSURE AT THE SFC BY SAT MORNING.
12 MODEL SUITE NOW SUGGESTING THAT A COLD FRONT WILL MOVE THRU
SOMETIME LATE SAT. HOWEVER...ANY UPPER LVL FORCING WITH SHORTWAVE
ENERGY LOOKS TO STILL REMAIN MAINLY NORTH OF THE AREA. WITH A
FAIRLY DRY AIR MASS IN PLACE...PWATS BELOW 1.0 INCHES...EXPECTING
THE FRONTAL PASSAGE TO BE MAINLY DRY...WITH NOTHING MORE THAN A
WIND SHIFT. HAVE KEPT THE LOW END SLIGHT CHC POPS FOR JUST THE FAR
WEST AREAS IN CASE OF TERRAIN DRIVEN CONVECTION. ANYTHING THAT
DOES FORM WILL BE GONE BY SAT EVENING.

THE HIGH PUSHES EAST SAT NIGHT THRU SUN NIGHT...BRINGING DRY AND
QUIET WX TO THE AREA. HIGHS HOVERING IN THE LOW TO UPPER 80S WITH
OVERNIGHT LOWS GENERALLY IN THE 60S.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
HIGH PRESS DOMINATES CONDITIONS SUN NIGHT INTO MONDAY. LATE MON
INTO TUE SWLY FLOW ADVECTS MOISTURE OVER OUR REGION INCREASING
THE CHANCE OF SHOWERS AND TSTMS. A CDFNT APPROACHES TUE NIGHT INTO
WED AND STALLS AROUND OUR AREA THROUGH THU... BRINGING ADDITIONAL
CHANCE OF SHOWERS AND TSTMS FOR THIS PERIOD. TEMPS WILL NEAR
NORMAL SUN AND GRADUALLY INCREASING INTO HE LOW 90S FOR WED.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
MAINLY VFR CONDITIONS FOR THE TAF PERIOD. TSTMS WILL MOVE THRU
THE TAF SITES EAST OF I-95 THRU 21Z. THESE STORMS COULD RESULT IN
GUSTY...VRB WINDS AND HEAVY RAIN WHICH COULD REDUCE VIS TO IFR.
SLY WINDS LATE THIS AFTN WILL SHIFT THIS EVENING TO THE NW BEHIND
A COLD FRONT MVG THRU. WNW FLOW WILL CONTINUE THRU FRI.

VFR CONDITIONS FRI NIGHT INTO NEXT MONDAY.

&&

.MARINE...
OCNL GUSTS OUTSIDE OF CONVECTION CURRENTLY REACHING SCA CRITERIA
SO WILL LET THE SCA CONTINUE THRU THIS EVENING. SLY FLOW WILL
BECOME NWLY DURING THE EVENING HOURS...WITH PSBL GUSTS TO 20 KTS
AS THE FRONT MOVES THRU. OTHERWISE...SUB-SCA CONDITIONS THEN THE
REMAINDER OF THE NIGHT THRU FRI.

SUB-SCA CONDITIONS WILL REMAIN IN PLACE FOR THE WEEKEND INTO
MONDAY WITH HIGH PRESSURE.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR
     ANZ530>543.

&&

$$
SYNOPSIS...SEARS
NEAR TERM...SEARS
SHORT TERM...SEARS
LONG TERM...IMR
AVIATION...SEARS/IMR
MARINE...SEARS/IMR


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