Dense Fog in Virginia, May 1, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
356 AM EDT THU MAY 1 2014

.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA THIS MORNING. WEAK HIGH
PRESSURE BUILDS IN TONIGHT. REINFORCING COLD FRONTS ARE EXPECTED
TO MOVE THROUGH FRIDAY AFTERNOON AND AGAIN OVER THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
A CUTOFF UPPER LOW WILL CONTINUE TO SPIN ACROSS THE MIDWEST THIS
MORNING. A COLD FRONT EXTENDS FROM SFC LOW PRESSURE STRETCHED ACROSS
THE GREAT LAKES.

SHOWERS AND THUNDERSTORMS HAVE TAPERED OFF AFTER A BUSY DAY OF HEAVY
RAIN EAST OF THE BLUE RIDGE. A FLASH FLOOD WATCH REMAINS IN EFFECT
EARLY THIS MORNING FOR THE I-95 CORRIDOR NORTH OF KNYG. MANY ROADS
REMAIN CLOSED IN THIS AREA DUE TO HEAVY RAIN FROM YESTERDAY AND MANY
RIVERS ARE SWOLLEN AND OUT OF THEIR BANKS. AS THE COLD FRONT MOVES
THROUGH THE POTOMAC HIGHLANDS THIS MORNING...SCT SHOWERS WILL
MOVE ACROSS THE WATCH AREA PRIOR TO SUNRISE. A THIN LINE OF SHOWERS
HAS DEVELOPED ACROSS THE CENTRAL FOOTHILLS. LESS THAN A TENTH OF AN
INCH OF ADDITIONAL RAIN IS EXPECTED ACROSS THE WATCH AREA. FURTHER
SOUTH... LESS THAN A QUARTER INCH IS EXPECTED MAINLY ALONG THE LINE
OF SHOWERS.

LIGHT SHOWERS EXISTS AHEAD OF THE COLD FRONT IN THE OHIO VALLEY AND
ACTIVITY IS EXPECTED TO WANE INTO THE MORNING HOURS WEST OF THE
APPALACHIANS. THE COLD FRONT IS EXPECTED TO SLOWLY MOVE EASTWARD
THROUGH THIS MORNING AND STALL ACROSS SRN MD DUE TO THE SW WINDS
BEHIND THE FRONT. SHOWERS ARE EXPECTED TO MOVE ALONG THE COLD FRONT
THROUGH THE DAY. DEWPTS IN THE 60S AHEAD OF THE FROPA AND SOME
INSTABILITY MAY PRODUCE ISOLATED THUNDERSTORMS WITHIN SHOWER
ACTIVITY MAINLY ACROSS THE PIEDMONT SRN MD AND SURROUNDING WATERS.
AS THE UPPER LOW SPINS AND SLOWLY MOVES EASTWARD...A RIBBON OF
VORTICITY WILL ENTER THE POTOMAC HIGHLANDS THIS AFTERNOON AND CROSS
THE REGION BY SUNSET. SCT SHOWERS AND A CU FIELD ARE EXPECTED MAINLY
ACROSS THE HIGHLANDS AND NRN MD. A 700MB TROUGH AXIS DOES NOT CROSS
THE REGION TODAY AND SW FLOW ALOFT WILL LEAD TO ENERGY MOVING ACROSS THE
WESTERN HALF OF THE CWA.

TEMPERATURES TODAY WILL DEPEND ON THE SPEEDINESS OF THE COLD FRONT
AS IT CROSSES THE I-95 CORRIDOR. DUE TO THE SCT SHOWERS AND CLOUD
COVER TEMPS ARE EXPECTED TO ONLY REACH THE LOW TO MID 70S EAST OF
THE BLUE RIDGE. WINDS WILL BECOME WESTERLY BY THIS EVENING AND DRIER
AIR WILL MIX INTO THE REGION TONIGHT.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
ANOTHER COLD FRONT IS POISED TO MOVE ACROSS THE CWA FRIDAY
AFTERNOON OR EVENING...BUT WITH RELATIVELY LIMITED MOISTURE AND
WEAK CONVERGENCE NO RAIN IS EXPECTED WITH THE FRONT EXCEPT PERHAPS
A FEW SHOWERS OVER THE HIGHLANDS. SOME CLOUDS MAY ACCOMPANY THE
FRONT...BUT THE AIR MASS ISN/T ALL THAT COOL BEHIND THE FRONT SO
NEAR NORMAL TEMPERATURES ARE EXPECTED.

SOMEWHAT OF A TROUGHY PATTERN CONTINUES INTO SATURDAY WITH A
REINFORCING COLD FRONT/SURFACE TROUGH. AGAIN...LIMITED MOISTURE
LIKELY MEANS A GENERAL DRY PASSAGE WITH SOME CLOUDS.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SHORT WAVE DIVING ESE ACROSS THE GREAT LAKES THEN OVER THE NORTHEAST
SUNDAY WILL PUSH A COLD FRONT ACROSS THE MID-ATLANTIC. LIMITED
MOISTURE WILL KEEP MEASURABLE PRECIP CHANCES LOW WITH THIS FRONT.
UPPER RIDGE BUILDING OVER THE CENTRAL CONUS WILL PUT THE
MID-ATLANTIC UNDER NORTHWEST FLOW ALOFT WITH LOW LEVEL BAROCLINIC
SITTING JUST SOUTH OF THE REGION ACROSS VA/NC. INDIVIDUAL SHORT
WAVES IN FLOW ALOFT ARE DIFFICULT TO PINPOINT...HOWEVER THE BEST
CHANCE FOR PRECIPITATION LOOKS TO BE MONDAY NIGHT INTO TUESDAY AS
STRONGER VORT MAX ROUND THE BASE OF LONG WAVE UPPER TROUGH ACROSS
THE NORTHEAST. TEMPERATURES WILL REALLY WARM BY MID WEEK AS UPPER
RIDGE BUILDS ACROSS THE EASTERN CONUS AND H85 TEMPS CLIMB INTO THE
LOWER TEENS CELSIUS.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
A COLD FRONT IS LOCATED ACROSS THE OHIO VALLEY THIS MORNING AND
SHOWERS ARE EXPECTED AHEAD OF THE FRONT THIS MORNING. MVFR/IFR
CONDITIONS HAVE BEEN OCCURING AHEAD OF THE FRONT OVERNIGHT. LITTLE
WIND FIELD HAS LED TO LOW VSBYS AND CIGS OUTSIDE SHOWERS OVERNIGHT.
CONDITIONS WILL CONTINUE TO GO BACK AND FORTH BETWEEN MVFR/IFR
THROUGH THE MORNING AHEAD OF THE FROPA. THE FRONT IS EXPECTED TO
MOVE SLOWLY THROUGH THE REGION AND STALL EAST OF BWI-MTN-DCA BY THE
AFTERNOON. SHOWERS ARE EXPECTED ALONG AND AHEAD OF THE FROPA THIS MORNING
AND AFTERNOON. WINDS WILL BECOME SW BEHIND THE FRONT.

ANOTHER COLD FRONT MOVES THROUGH FRIDAY AFTERNOON /LIKELY DRY/
WITH WINDS SHIFTING TO THE NORTHWEST BEHIND THE FRONT. A COLD
FRONT WITH LIMITED MOISTURE WILL PUSH THROUGH THE REGION SUNDAY. A
STATIONARY WARM FRONT WILL BRING UNSETTLED CONDITIONS INTO EARLY
NEXT WEEK.

&&

.MARINE...
SOUTHERLY WINDS ACROSS THE WATERS WILL CONTINUE TO DIMINISH THIS
MORNING. A SCA IS IN EFFECT UNTIL 6AM THIS MORNING. A COLD FRONT
WILL APPROACH THE WATERS LATE THIS MORNING AND IS EXPECTED TO STALL.
SHOWERS ARE EXPECTED THROUGH THIS AFTERNOON. A FEW SHOWERS MAY
BECOME STRONG ACROSS THE LOWER BAY AND TIDAL POTOMAC AS SHOWERS MOVE
ALONG THE FROPA THIS AFTERNOON.

MARGINAL SCA CONDITIONS ARE POSSIBLE OVER PORTIONS OF THE WATERS
FRIDAY AFTERNOON/EVENING IN NW FLOW BEHIND A FRONT. ANOTHER COLD
FRONT WILL MOVE THROUGH THE REGION SUNDAY AS WINDS INCREASE OUT OF
THE WEST THEN NORTHWEST INTO SUNDAY NIGHT. UNSETTLED CONDITIONS
WILL PREVAIL INTO EARLY NEXT WEEK DUE TO A STATIONARY WARM FRONT.

&&

.HYDROLOGY...
HAVE CANCELLED MUCH OF THE FLASH FLOOD WATCH EXCEPT FOR JUST A FEW
COUNTIES IN MARYLAND WHERE BANDS OF MODERATE RAIN MAY CONTINUE
THROUGH DAYBREAK OR SO. CREEKS...STREAMS AND RIVERS REMAIN
HIGH...AND THERE ARE STILL ONGOING FLOOD ISSUES IN SOME PORTIONS
OF MD/VA DUE TO HEAVY RAIN FROM YESTERDAY. SEVERAL RIVER FLOOD
WARNINGS ARE ALSO IN EFFECT FOR THE POTOMAC AND SHENANDOAH BASINS.

&&

.TIDES/COASTAL FLOODING...
MAX ASTRONOMICAL TIDE WILL OCCUR THIS MORNING...WITH WATER LEVELS
EXPECTED TO PRODUCE MODERATE TIDAL FLOODING ALONG MUCH OF THE
WESTERN SHORE OF THE CHESAPEAKE BAY /UP THROUGH BALTIMORE COUNTY/
AND ALSO ALONG THE UPPER TIDAL POTOMAC RIVER. MINOR TIDAL FLOODING
IS EXPECTED FURTHER NORTH ALONG THE BAY OVER HARFORD COUNTY AND
ALONG THE REST OF THE TIDAL POTOMAC.

THERE IS SOME UNCERTAINTY WITH THE MAGNITUDE OF POSSIBLE FLOODING
BEGINNING WITH THE HIGH TIDE THIS EVENING /WHICH WILL BE THE
LOWER OF THE NEXT TWO/ ALONG THE WESTERN SHORE OF THE CHESAPEAKE
BAY. WINDS SHIFTING TO THE WEST ARE MODELED TO RESULT IN
DECREASING TIDAL ANOMALIES AND CBOFS SUGGESTS ANNAPOLIS BELOW
MINOR THRESHOLD BY EVENING/S HIGH TIDE. THEREFORE...HAVE NOT
EXTENDED HEADLINES INTO THE EVENING.

ON THE POTOMAC...PARTICULARLY THE UPPER TIDAL POTOMAC...SOME
FRESHWATER FROM HEAVY RAINFALL WILL BEGIN TO MAKE ITS WAY DOWN
THIS EVENING AND ALSO INTO FRIDAY. BUT LATEST GUIDANCE SUGGESTS
THIS MAY BE MORE OF THE MINOR VARIETY THAN MODERATE. IT BEARS
WATCHING...EVENING HIGH TIDES ARE 1030PM-1130PM SO THERE IS TIME
TO MAKE A HEADLINE DECISION. FOR NOW FOCUS IS ON EXPECTED MODERATE
THIS MORNING.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD WARNING UNTIL NOON EDT TODAY FOR DCZ001.
MD...FLASH FLOOD WATCH UNTIL 6 AM EDT EARLY THIS MORNING FOR MDZ006-
     007-010-011-013-014.
     COASTAL FLOOD ADVISORY UNTIL NOON EDT TODAY FOR MDZ007-013-016.
     COASTAL FLOOD WARNING UNTIL NOON EDT TODAY FOR MDZ011-014-017-
     018.
VA...COASTAL FLOOD ADVISORY UNTIL NOON EDT TODAY FOR VAZ052-053-055-
     057.
     COASTAL FLOOD WARNING UNTIL NOON EDT TODAY FOR VAZ054.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
     ANZ530>543.

&&

SYNOPSIS...BPP
NEAR TERM...HAS
SHORT TERM...BPP
LONG TERM...AEB
AVIATION...HAS/BPP/AEB
MARINE...HAS/BPP/AEB
HYDROLOGY...BPP
TIDES/COASTAL FLOODING...BPP

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
919 PM EDT WED APR 30 2014

ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057-
011000-
CHESAPEAKE BAY NORTH OF POOLES ISLAND MD-
CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT MD-
CHESAPEAKE BAY FROM SANDY POINT TO NORTH BEACH MD-
CHESAPEAKE BAY FROM NORTH BEACH TO DRUM POINT MD-
CHESAPEAKE BAY FROM DRUM POINT MD TO SMITH POINT VA-
TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD MD-
TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND MD-
TIDAL POTOMAC FROM COBB ISLAND MD TO SMITH POINT VA-
PATAPSCO RIVER INCLUDING BALTIMORE HARBOR-
CHESTER RIVER TO QUEENSTOWN MD-EASTERN BAY-
CHOPTANK RIVER TO CAMBRIDGE MD AND THE LITTLE CHOPTANK RIVER-
PATUXENT RIVER TO BROOMES ISLAND MD-
TANGIER SOUND AND THE INLAND WATERS SURROUNDING BLOODSWORTH
ISLAND-DISTRICT OF COLUMBIA-NORTHERN BALTIMORE-HARFORD-
SOUTHERN BALTIMORE-PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ST. MARYS-
CALVERT-PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX-
ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA-
KING GEORGE-
919 PM EDT WED APR 30 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE MARYLAND PORTION OF THE
CHESAPEAKE BAY...TIDAL POTOMAC RIVER...AND ADJACENT COUNTIES IN
CENTRAL MARYLAND AND NORTHERN VIRGINIA AS WELL AS THE DISTRICT OF
COLUMBIA.

.DAY ONE...TONIGHT

NUMEROUS FLOOD AND FLASH FLOOD WARNINGS ARE IN EFFECT FOR THE
AREA NEAR AND WEST OF INTERSTATE 95. A FLASH FLOOD WATCH REMAINS
IN EFFECT FOR THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS
THROUGH TONIGHT.

ON THE WESTERN SHORE OF THE CHESAPEAKE BAY FROM SOUTHERN BALTIMORE
THROUGH ST MARYS COUNTIES AND FOR WASHINGTON DC AND ALEXANDRIA...
ALONG THE UPPER TIDAL POTOMAC RIVER...A COASTAL FLOOD WARNING IS
IN EFFECT UNTIL MIDNIGHT. A COASTAL FLOOD ADVISORY IS IN EFFECT
FOR HARFORD COUNTY UNTIL MIDNIGHT.

ALONG THE REST OF THE TIDAL POTOMAC RIVER...A COASTAL FLOOD
ADVISORY IS IN EFFECT THROUGH TONIGHT.

A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE MARYLAND
CHESAPEAKE BAY AND TIDAL POTOMAC RIVER TONIGHT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THE COASTAL FLOOD WARNING REMAINS IN EFFECT ALONG THE WESTERN
SHORE OF THE CHESAPEAKE BAY...AND WASHINGTON DC AND ALEXANDRIA
ALONG THE UPPER TIDAL POTOMAC RIVER THURSDAY MORNING...WHILE A
COASTAL FLOOD ADVISORY REMAINS IN EFFECT ALONG THE REST OF THE
TIDAL POTOMAC RIVER.

FRESHWATER FROM HEAVY RAINFALL MAY CAUSE MODERATE FLOODING ALONG
THE TIDAL POTOMAC RIVER NEAR WASHINGTON DC BY FRIDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION NOT ANTICIPATED THIS EVENING...ALTHOUGH REPORTS
OF ANY FLOODING SHOULD BE RELAYED TO THE NATIONAL WEATHER SERVICE.

MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504-
WVZ050>053-055-501>506-011000-
WASHINGTON-FREDERICK MD-CARROLL-MONTGOMERY-HOWARD-
EXTREME WESTERN ALLEGANY-CENTRAL AND EASTERN ALLEGANY-AUGUSTA-
ROCKINGHAM-SHENANDOAH-FREDERICK VA-PAGE-WARREN-CLARKE-NELSON-
ALBEMARLE-GREENE-MADISON-RAPPAHANNOCK-LOUDOUN-ORANGE-CULPEPER-
NORTHERN FAUQUIER-SOUTHERN FAUQUIER-WESTERN HIGHLAND-
EASTERN HIGHLAND-HAMPSHIRE-MORGAN-BERKELEY-JEFFERSON-HARDY-
WESTERN GRANT-EASTERN GRANT-WESTERN MINERAL-EASTERN MINERAL-
WESTERN PENDLETON-EASTERN PENDLETON-
919 PM EDT WED APR 30 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN WEST VIRGINIA...
NORTHERN AND CENTRAL VIRGINIA...AND CENTRAL AND WESTERN MARYLAND
WITH THE EXCEPTION OF GARRETT COUNTY.

.DAY ONE...TONIGHT

NUMEROUS FLOOD AND RIVER FLOOD WARNINGS ARE IN EFFECT FOR LOCATIONS
EAST OF THE BLUE RIDGE MOUNTAINS. A FLASH FLOOD WATCH REMAINS IN
EFFECT FOR PORTIONS OF NORTH CENTRAL MARYLAND OVERNIGHT.

NUMEROUS RIVER FLOOD WARNINGS ARE IN EFFECT.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NUMEROUS RIVER FLOOD WARNINGS ARE IN EFFECT. RIVER FLOOD WATCHES
REMAIN IN EFFECT FOR THE POTOMAC AND SHENANDOAH RIVER BASINS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION NOT ANTICIPATED THIS EVENING...ALTHOUGH REPORTS
OF ANY FLOODING SHOULD BE RELAYED TO THE NATIONAL WEATHER SERVICE.