Area Forecast Discussion


289 
FXUS61 KLWX 251854
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
254 PM EDT FRI JUL 25 2014
.SYNOPSIS...
HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT BEFORE
MOVING OFF THE COAST SATURDAY. AN UPPER-LEVEL DISTURBANCE WILL
PASS THROUGH THE AREA SUNDAY AND A POTENT COLD FRONT WILL MOVE
THROUGH MONDAY. HIGH PRESSURE WILL RETURN FOR THE MIDDLE PORTION
OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
HIGH PRESSURE IS IN CONTROL TODAY AND DRY CONDITIONS WILL
PERSIST. TEMPS WILL CONTINUE TO RISE INTO THE UPPER 70S IN THE
MTNS TO THE LOW 80S NEAR THE INTERSTATE 95 CORRIDOR. HIGH PRESSURE
WILL MOVE OFF THE COAST TONIGHT AND WINDS WILL BECOME SRLY
TONIGHT. DEWPTS WILL BEGIN TO INCREASE INTO SATURDAY.
HIGH PRESSURE WILL BE WELL OFF THE EAST COAST SATURDAY MORNING AND 
SRLY FLOW WILL CONTINUE TO DRAW IN HIGHER DEWPTS AS WELL AS WARMER 
TEMPS. FCST MAX TEMPS WILL REACH THE MID TO UPPER 80S SATURDAY 
AFTERNOON. WESTERLY FLOW ALOFT WILL LEAD TO UPSTREAM DISTURBANCES
REACHING THE MID-ATLANTIC AND A LEE TROUGH TO FORM. A SHORTWAVE
TROUGH CURRENTLY RESPONSIBLE FOR SHOWERS AND THUNDERSTORMS ACROSS
IA-IL WILL REACH THE AREA SATURDAY AFTERNOON. IT IS EXPECTED TO
WEAKEN BUT WITH THE SRLY FLOW ADVECTING WARM AND MOIST CONDITIONS
INTO THE REGION A FEW SHOWERS WILL BE POSSIBLE IN THE HIGHLANDS
AND AHEAD OF THE LEE TROUGH. AN ISOLATED THUNDERSTORM WILL BE
POSSIBLE ACROSS THE I-95 CORRIDOR SAT AFTERNOON. ACTIVITY WILL
WANE TOWARDS SUNSET.
A STRONG SHORTWAVE TROUGH WILL DROP INTO THE NRN PLAINS SATURDAY 
WHILE CONVECTION WILL BE ONGOING AHEAD OF A COLD FRONT ACROSS THE
MIDWEST SATURDAY AFTERNOON AND EVENING. SOME SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO BECOME SEVERE AND THIS ACTIVITY WILL PROPAGATE
EASTWARD AND POTENTIALLY IMPACT THE POTOMAC HIGHLANDS LATE
SATURDAY NIGHT/EARLY SUNDAY MORNING. THERE ARE UNCERTAINTIES
PERTAINING TO THE TRACK OF A POTENTIAL MCS SUNDAY MORNING WHICH
WILL THEN IMPACT THE AMT OF CLOUD COVER AND THEREFORE INSTABILITY
THE MID- ATLANTIC GAINS ON SUNDAY.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
A WARM FRONT WILL MOVE ACROSS THE REGION SATURDAY NIGHT/SUN
MORNING AND MOISTURE WILL CONTINUE TO ADVECT INTO THE MID-ATLANTIC
SUNDAY. LOW PRESSURE WILL BE ACROSS THE GREAT LAKES AND A COLD
FRONT WILL BE STRETCHED FROM PA TO OHIO TO MO. AS THE STRONG
SHORTWAVE TROUGH NEARS SHEAR WILL INCREASE AND SHOWERS AND
THUNDERSTORMS ARE LIKELY. DEPENDING ON THE AMT OF INSTABILITY THE
REGION GETS WITH THE DEPARTING MCS FROM THE OHIO VALLEY... SEVERE
STORMS MAY BE POSSIBLE WITH THE THREATS OF DMG WINDS LARGE HAIL
ISOLATED TORNADOES AND HEAVY RAIN. SREF ENSEMBLE MEMBERS SHOW A
RANGE OF CAPE SOLUTIONS FOR SUNDAY WITH 500 TO 3000 J/KG POSSIBLE.
ONE THING THAT IS CERTAIN IS THAT SHEAR PROFILES INCREASE SUNDAY
AND HODOGRAPHS BECOME LINEAR WITH 40-50 KTS AT 10-15K FEET. A
STRONG LINE OF THUNDERSTORMS WILL BE POSSIBLE SUN AFTERNOON AND
EVENING.
OUTFLOW BOUNDARIES AND THE CLOSE PROXIMITY TO THE SFC LOW ACROSS 
OH/PA/NY WILL LEAD TO THE THREAT OF SVR THUNDERSTORMS CAPABLE OF
PRODUCING TORNADOES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
SHEAR PROFILES INCREASE MARKEDLY SUNDAY EVENING...INCLUDING IN THE 
LOWEST FEW KILOMETERS. THIS WILL ENHANCE/ORGANIZE CONVECTION ON THE 
NOSE OF A 50+ KNOT 500 MB JET. HIGH PWATS AND MODERATE CAPE SUGGEST 
A MYRIAD OF HAZARDS FROM SEVERE WEATHER TO HEAVY RAIN PERSISTING 
WELL INTO SUNDAY EVENING AS A STRONG SHORTWAVE TROUGH DIVES TOWARDS 
THE REGION FROM THE GREAT LAKES.
MODELS DIFFER IN HOW QUICKLY THE UPPER TROUGH AND SURFACE COLD FRONT 
CROSS THE AREA...BUT IF THE FRONT DOES NOT CLEAR THE COAST BY MONDAY 
AFTERNOON THEN A SEVERE WEATHER THREAT COULD ARISE AGAIN. BEST 
CHANCE FOR THIS WOULD BE EAST OF THE BLUE RIDGE MOUNTAINS.
FOLLOWING AN ACTIVE START TO THE WEEK...A LARGE AREA OF HIGH 
PRESSURE WILL BUILD TOWARD THE REGION FROM CANADA RESULTING IN DRY 
WEATHER AND BELOW NORMAL TEMPERATURES AND HUMIDITY FOR MOST OF THE 
WEEK.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED TODAY AND TONIGHT. HIGH PRESSURE MOVES OFF
THE EAST COAST SATURDAY AND SRLY WINDS AROUND 10-15 KTS WILL OCCUR
THROUGH THE AFTERNOON. A FEW ISO SHOWERS WILL BE POSSIBLE NEAR
DCA-BWI-MTN SATURDAY AFTERNOON. SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE SUNDAY AND MVFR/IFR CONDITIONS WILL BE POSSIBLE. A FEW
THUNDERSTORMS MAY PRODUCE GUSTY WINDS...LARGE HAIL AND ISOLATED
TORNADOES.
MVFR OR LWR CIGS/VSBYS IN SHWRS/TSTMS SUN NIGHT-MON...IMPROVING TO 
VFR MON NIGHT. SW WIND AROUND 10 KTS BECOMING NW 15-20 KTS AND GUSTY 
MON EVENING W/ COLD FROPA.
&&
.MARINE...
NRLY WINDS WILL BECOME SRLY BY THIS EVENING AND CONTINUE THROUGH
THE WEEKEND. WINDS WILL INCREASE SATURDAY AFTERNOON AS SRLY
CHANNELING OCCURS. A SCA IS IN EFFECT FROM THE MD CHESAPEAKE BAY
SOUTH OF POOLES ISLAND AND LOWER TIDAL POTOMAC RIVER SUN AFTERNOON
THROUGH THE EVENING. ISOLATED SHOWERS ARE POSSIBLE SAT AFTERNOON. 
A COLD FRONT APPROACHES SUNDAY AND SHOWERS AND THUNDERSTORMS ARE
LIKELY. SOME STORMS MAY PRODUCE GUSTY WINDS LARGE HAIL AND
WATERSPOUTS CREATING LOW VSBYS.
SHOWERS/STRONG STORMS LIKELY SUN NIGHT-MON...SUBSIDING MON EVENING. 
SCA WINDS/SEAS PROBABLE MON EVENING INTO TUES WITH GUSTY NW FLOW 
BEHIND COLD FRONT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM SATURDAY TO 2 AM EDT SUNDAY FOR 
     ANZ531>534-537-539>543.
&&
$$
SYNOPSIS...HAS
NEAR TERM...HAS
SHORT TERM...HAS/DFH
LONG TERM...DFH
AVIATION...HAS/DFH
MARINE...HAS/DFH