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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
307 AM EDT SAT JUL 26 2014

.SYNOPSIS...

HIGH PRESSURE IS MOVING OFFSHORE. LOW PRESSURE IS EXPECTED TO
TRACK ACROSS PENNSYLVANIA SUNDAY NIGHT WITH AN ASSOCIATED COLD
FRONT MOVING INTO THE MID ATLANTIC. A REINFORCING FRONT WILL CROSS THE
REGION MONDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE FRONT BRINGING
COOLER AND DRIER CONDITIONS DURING MIDWEEK.

&&

.NEAR TERM /TODAY/...

AN UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION THIS 
MORNING. A BKN TO OVC DECK OF MID-LEVEL CLOUDS IS EXPECTED WITH THIS 
DISTURBANCE. A SURFACE TROUGH WILL DEVELOP OVER THE REGION...MOST 
LIKELY EXTENDING FROM NORTH-CENTRAL MARYLAND SOUTH AND WEST INTO 
CENTRAL VIRGINIA. THERE IS A SMALL THETA-E GRADIENT AND PWAT 
GRADIENT ALONG THE BOUNDARY. A FEW SHOWERS CANNOT BE RULED OUT NEAR 
AND EAST OF THE BOUNDARY THIS MORNING...BUT MOST LOCATIONS WILL 
LIKELY END UP DRY SINCE MOST OF THE FORCING FROM THE UPPER-LEVEL 
DISTURBANCE IS EXPECTED TO REMAIN TO OUR NORTH. 

HIGH PRESSURE WILL CONTINUE TO MOVE OUT INTO THE ATLANTIC LATER 
TODAY. A SOUTHERLY FLOW WILL ALLOW FOR WARMER AND MORE HUMID 
CONDITIONS TO RETURN...AND THERE SHOULD BE AT LEAST SOME SUNSHINE 
BEHIND THE DEPARTING UPPER-LEVEL DISTURBANCE. MAX TEMPS WILL RANGE 
FROM THE 70S IN THE MOUNTAINS TO THE UPPER 80S/NEAR 90 IN THE 
WASHINGTON AND BALTIMORE METROPOLITAN AREAS. 

THE HEAT AND HUMIDITY WILL LEAD TO AN UNSTABLE ATMOSPHERE THIS 
AFTERNOON...ESPECIALLY NEAR AND EAST OF THE SURFACE TROUGH ACROSS 
THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS INTO SOUTHERN 
MARYLAND. A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED TO 
DEVELOP ACROSS THESE LOCATIONS. COVERAGE WILL BE ISOLATED TO WIDELY 
SCATTERED SINCE FORCING ALONG THE PRESSURE TROUGH WILL BE WEAK.

&&

.SHORT TERM /TONIGHT/...

A POTENT SHORTWAVE IN THE WESTERLY FLOW ALOFT WILL APPROACH THE AREA 
TONIGHT. MOST OF THE FORCING SHOULD REMAIN TO THE WEST...BUT THE 
SURFACE TROUGH WILL STRENGTHEN OVERHEAD AND EVEN RETROGRADE 
WESTWARD. THEREFORE...A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE 
TONIGHT...BUT COVERAGE ACROSS MOST AREAS SHOULD BE ISOLATED OR 
WIDELY SCATTERED SINCE MOST OF THE FORCING WILL REMAIN TO OUR WEST 
OVER THE OHIO VALLEY. MIN TEMPS WILL RANGE FROM THE 60S IN THE 
MOUNTAINS TO THE MIDDLE 70S IN DOWNTOWN WASHINGTON AND BALTIMORE...
AND IT WILL FEEL NOTICEABLY MORE HUMID.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...

THE PRIMARY ACTION DURG THE XTND PD LOOKS TO BE COMING AT THE
BEGINNING. SYNOPTICALLY THIS SUMMER CERTAINLY HAS BEEN OUT OF THE
NORM (IE..AN ABSENCE OF THE SUB TROP HIGH) AND IT LOOKS LK THIS WL
HOLD TRUE FOR THE END OF JUL AS WELL. 

IT APPEARS THAT AN UNUSUALLY STRONG AREA OF LOW PRES WL BE
TRACKING ACROSS PA SUN EVE. THIS WL PLACE THE MID ATLC SUN IN AN
UNSTABLE AIR MASS W/ CAPES OVR 1000. SPC HAS ENTIRE CWA IN A SLT
RISK. ONE THING THAT WOULD MAKE THIS THREAT STRONGER IS IF AREA GETS
BRKS IN CLDS DURG MIDDAY TO ALLOW FOR HTG/INSTABILITY. HIGHS SEASONABLE...
GNRLY IN U80S...PSBLY 90 IN THE CIITES.

CHC FOR RA/TSTMS XPCTD TO CONT SUN NGT AHD OF A CD FNT. HOW MUCH
INSTABILITY WL RMN POST-SUNSET WL HELP TO DETERMINE IF THERE WL BE
A CONT SVR THREAT. LOWS RANGING FM THE M60S TO L70S.

CURRENTLY IF LOOKS LK THE ACTUAL CD FNT WON'T PUSH E OF THE RGN
UNTIL LATE MON...HENCE MORE POPS/CHCS FOR CNVCTN. HIGHS IN LM80S.

AFTR THAT THE NEXT SVRL DAYS - THE LAST PART OF JUL...THE
CONTINENTAL U.S. SHOULD BE UNDER A WRN RDG/ERN TROF. THIS WL KEEP
TEMPS IN THE MID ATLC BLO NRML. AS I'VE WRITTEN IN SVRL DSCNS
RECENTLY WE ARE AT THE CLIMATOLOGICALLY WARMEST TIME OF THE YR -
HIGHS SHOULD GNRLY BE IN THE U80S/LOWS IN THE MU60S. AS OF NOW IT
LOOKS LK HIGHS TUE-FRI SHOULD BE IN THE L80S. LOW TEMPS OUTSIDE OF
WARMER CITIES WL BE A60...PSBLY EVEN INTO THE U50S. IT LOOKS LK IT
SHOULD BE DRY TUE-FRI.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...

PATCHY BR IS POSSIBLE EARLY THIS MORNING ACROSS THE WESTERN 
TERMINALS. VFR CONDITIONS WILL PERSIST FOR THE REST OF TODAY. A FEW 
SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE EASTERN 
TERMINALS...ESPECIALLY THIS AFTERNOON. HOWEVER...COVERAGE WILL BE 
ISOLATED TO WIDELY SCATTERED. 

A FEW MORE SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE 
TERMINALS TONIGHT...BUT AGAIN COVERAGE WILL BE ISOLATED TO WIDELY 
SCATTERED SINCE MOST OF THE FORCING WILL BE TO OUR WEST OVER THE 
OHIO VALLEY. PATCHY BR MAY REDUCE VSBYS LATE TONIGHT. 

IN THE XTND...TSTMS ARE PSBL SUN..SUN NGT...AND MON. IT IS LKLY
THAT L.T. VFR CONDS WL OCCUR IF STORMS DVLP OVR AN AIRPORT ALONG
W/ THE PSBLTY OF STRONG WINDS.

CONDS XPCTD TO BE VFR TUE AND WED. 

&&

.MARINE...

A SOUTHERLY FLOW HAS DEVELOPED AROUND DEPARTING HIGH PRESSURE AND 
THE SOUTHERLY FLOW WILL CONTINUE THROUGH TONIGHT. THE PRESSURE 
GRADIENT WILL STRENGTHEN A BIT THIS AFTERNOON AND TONIGHT...CAUSING 
SOUTHERLY WINDS TO CHANNEL UP THE MARYLAND CHESAPEAKE BAY AND LOWER 
TIDAL POTOMAC RIVER. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE 
MARYLAND CHESAPEAKE BAY FROM SOUTH OF POOLES ISLAND TO SMITH 
POINT...AND THE LOWER TIDAL POTOMAC RIVER FROM COBB ISLAND TO SMITH 
POINT. WIND GUSTS MAY BE MARGINAL THIS AFTERNOON DUE TO THE 
RELATIVELY COOLER WATERS...BUT WILL CONTINUE WITH THE HEADLINE FOR 
NOW DUE TO THE STRENGTHENING GRADIENT. HIGHER CONFIDENCE WITH SCA 
WIND GUSTS IS FOR TONIGHT. 

TSTMS XPCTD ON THE WATERS...ESPECIALLY SUN AFTN/EVE. THESE MAY
GENERATE STRONG GUSTY WINDS. AN SCA IS XPCTD MON AS A CD FNT MOVES
THRU THE WATERS. THIS MAY CONT INTO MON NGT. TUE-THU LOOK MORE
TRANQUIL.


&&

.TIDES/COASTAL FLOODING...

A LIGHT SOUTHERLY FLOW HAS CAUSED TIDAL ANOMALIES TO INCREASE TO 
AROUND ONE-HALF FOOT ABOVE NORMAL. THIS WILL CAUSE WATER LEVELS TO 
APPROACH MINOR FLOODING FOR SENSITIVE AREAS NEAR HIGH TIDE THIS 
MORNING FOR LOCATIONS ALONG THE WESTERN SHORE OF THE MARYLAND 
CHESAPEAKE BAY AND THE SHORE OF THE UPPER TIDAL POTOMAC RIVER. 
HOWEVER...WATER LEVELS SHOULD REMAIN JUST BELOW THESE THRESHOLDS 
SINCE THE FLOW WILL BE LIGHT. THE HIGH TIDE CYCLE THIS AFTERNOON AND 
EVENING WILL BE THE LOWER OF THE TWO...SO MINOR FLOODING IS NOT 
EXPECTED. 

HOWEVER...THE SOUTHERLY FLOW MAY STRENGTHEN A BIT TONIGHT AND THE 
HIGH TIDE CYCLE LATE TONIGHT INTO SUNDAY MORNING WILL BE THE HIGHER 
OF THE TWO. MINOR TIDAL FLOODING IS POSSIBLE FOR SENSITIVE AREAS 
NEAR HIGH TIDE LATE TONIGHT INTO SUNDAY MORNING. 

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 AM EDT 
     SUNDAY FOR ANZ531>534-537-539>543.

&&

$$
PRODUCTS...BJL/WOODY!

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