Damaging Winds in Maryland, August 5, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
324 PM EDT FRI AUG 5 2005

.SHORT TERM (TONIGHT THROUGH SATURDAY)...
PRE-FRONTAL CONVECTIVE CELLS HAVE BEGUN TO POP ON THE RADAR. THERE/S
ONE WEAK BOUNDARY STRETCHED FROM NE TO SW ACROSS OUR CWA THAT THESE
CELLS ARE MORE THAN LIKELY FIRING UPON. THE PRIMARY SYNOPTIC FRONT
REMAINS TO OUR NORTH IN PA...AND WILL CONTINUE TO MOVE SOUTH AS THE
AFTERNOON/EVENING PROGRESSES.

OUR ENTIRE CWA IS VERY UNSTABLE...WITH CAPES EXCEEDING 3000 J/KG.
HOWEVER...0-6 KM SHEAR IS LESS THAN 10 KT...AND THIS SHOULD HELP TO
PRECLUDE WIDESPREAD ORGANIZED SEVERE CONVECTION. BUT WITH HIGH
INSTABILITY IN PLACE AND LOW LEVEL BOUNDARIES HELPING TO ENHANCE LOW
LEVEL CONVERGENCE...GENERAL SCATTERED COVERAGE OF CONVECTION (SINGLE
TO MULTICELLULAR) IS EXPECTED THROUGH THE EVENING AND THE TALLEST
GROWING STORMS WILL HAVE THE POTENTIAL TO BRING DOWNBURST TYPE WINDS
AS THE INVERTED V ON FORECAST BUFKIT SOUNDINGS IMPLY. MARGINALLY
SEVERE HAIL WOULD NOT BE OUT OF THE QUESTION EITHER IF STRONG CORES
CAN GROW HIGH ENOUGH.

PRIMARY COLD FRONT WILL CROSS OUR NORTHERN CWA BY 00Z...THEN  SLOW
DOWN AND STALL ACROSS OUR EXTREME SOUTHERN CWA. WILL LOWER
SCATTERED COVERAGE TO ISOLATED COVERAGE ACROSS OUR NORTH AFTER
MIDNIGHT...BUT WILL KEEP SCATTERED COVERAGE GOING ALL NIGHT LONG TO
THE SOUTH.

ON SATURDAY...WITH THE FRONT RESIDING ACROSS OUR EXTREME SOUTHERN
CWA...FEEL THAT KEEPING CHC POPS DOWN THERE IS WARRANTED. MOST OF
THE MOS NUMBERS EVEN HAVE CHC POPS NORTH TO THE MASON DIXON LINE.
IF FRONT DOES NOT MAKE IT AS FAR AS PREDICTED...OR MOVES BACK TO THE
NORTH SOONER THAN EXPECTED...CHC POPS WOULD BE REASONABLE
EVERYWHERE. HOWEVER...WILL KEEP SLGT CHC POPS NORTH ASSUMING FRONT
REMAINS WELL TO THE SOUTH THROUGH THE DAYTIME ON SATURDAY.

&&

.LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)...
THE BEGINNING OF THE EXTENDED FORECAST IS DOMINATED BY THE NEARLY
STATIONARY FRONTAL BOUNDARY. ANOTHER FRONT IS EXPECTED BY THE END OF
NEXT WEEK.

THE 500MB FLOW HAS FLATTENED OUT IN THE BEGINNING OF THE PERIOD...AS
THE TROUGH HAS WEAKENED AND SHEARED OUT. THE SHEAR AXIS STAYS IN
PLACE THROUGH MOST OF SUNDAY OVER THE CENTRAL PORTIONS OF THE
CWFA...BEFORE FINALLY DISSIPATING LATE SUNDAY/EARLY MONDAY. MID
LEVEL RIDGING BEGINS TO BUILDING BACK OVER THE REGION BY LATE
MONDAY...WITH THE HIGH PRESSURE CENTERED EAST OF THE SOUTHEAST
STATES. THE GFS IS PROGGING SEVERAL SHORTWAVES TO MOVE AROUND THE
PERIPHERY OF THE HIGH THROUGH THE FIRST PART OF NEXT WEEK. THESE
FEATURES ARE GENERALLY HARD TO TIME...BUT WITH A MOIST AIRMASS IN
PLACE...HAVE KEPT SLIGHT/CHANCE POPS IN THE REMAINDER OF THE
FORECAST.

THE SURFACE FRONT WILL PRETTY MUCH STICK AROUND FOR MUCH OF THE
WEEKEND BEFORE BECOMING DIFFUSE LATE SUNDAY/EARLY MONDAY. THE
BOUNDARY IS PROGGED TO MAKE IT TO SOUTHERN PORTIONS OF THE
CWFA...BUT WILL WAVE BACK AND FORTH OVER CENTRAL PORTIONS OF THE
CWFA THROUGH THE WEEKEND. THE BOUNDARY WILL SERVE TO FOCUS SHOWERS
AND THUNDERSTORMS THROUGH EARLY MONDAY BEFORE DISSIPATING.

HIGH PRESSURE WILL BE SITUATED JUST OFFSHORE FOR MONDAY AND
TUESDAY...WITH SOUTHERLY FLOW KEEPING THE ATMOSPHERE MOIST AND
UNSTABLE. LATE WEDNESDAY/EARLY THURSDAY THE NEXT FRONTAL BOUNDARY IS
EXPECTED TO MOVE EAST OVER THE CWFA...WITH HIGH PRESSURE BUILDING
BACK OVER THE AREA FOR NEXT WEEKEND.

TEMPERATURE GUIDANCE WAS PRETTY CLUSTERED AND SPLIT THE DIFFERENCE.

&&

.AVIATION...
TERMINALS WILL BE VULNERABLE TO THUNDERSTORMS PRODUCING AT LEAST
MVFR CONDITIONS THROUGH THE AFTERNOON/EARLY EVENING. WIND DIRECTION
A LITTLE TRICKY AS INITIAL WEAK FRONT RESIDES OVER THE CWA...WITH
THE PRIMARY BOUNDARY STILL IN PA AT 18Z. PRIMARY BOUNDARY WILL LEAD
TO A SHIFT IN WIND DIRECTION TO NW...THAT IS ADEQUATELY COVERED IN
INDIVIDUAL TAFS.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&

SHORT TERM/AVIATION...PELOQUIN
LONG TERM...LISTEMAA

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1156 AM EDT FRI AUG 5 2005

ANZ530>537-DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-
025>031-036>042-050>057-WVZ048>055-061015-
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-
DISTRICT OF COLUMBIA-ALLEGANY-WASHINGTON-FREDERICK MD-CARROLL-
NORTHERN BALTIMORE-HARFORD-MONTGOMERY-HOWARD-SOUTHERN BALTIMORE-
PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ST. MARYS-CALVERT-HIGHLAND-
AUGUSTA-ROCKINGHAM-SHENANDOAH-FREDERICK VA-PAGE-WARREN-CLARKE-
NELSON-ALBEMARLE-GREENE-MADISON-RAPPAHANNOCK-FAUQUIER-LOUDOUN-
ORANGE-CULPEPER-PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX-
ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA-
KING GEORGE-GRANT-MINERAL-HAMPSHIRE-MORGAN-BERKELEY-JEFFERSON-
PENDLETON-HARDY-
1156 AM EDT FRI AUG 5 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MARYLAND WEST OF THE
EASTERN SHORE INCLUDING THE CHESAPEAKE BAY AND EAST OF GARRETT
COUNTY...EASTERN WEST VIRGINIA...NORTHERN AND CENTRAL VIRGINIA...
WASHINGTON DC AND THE TIDAL POTOMAC RIVER.

.DAY ONE...THIS AFTERNOON AND TONIGHT

AS A COLD FRONT APPROACHES THIS AFTERNOON AND EVENING...A FEW
THUNDERSTORMS WILL BE CAPABLE OF PRODUCING STRONG DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
514 PM EDT FRI AUG 05 2005

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0500 PM     TSTM WND DMG     PURCELLVILLE            39.14N 77.71W
08/05/2005                   LOUDOUN            VA   EMERGENCY MNGR

            TREES AND WIRES DOWN IN PURCELLVILLE/ROUND HILL AREA.

&&

JL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
708 PM EDT FRI AUG 05 2005

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0622 PM     TSTM WND DMG     SPERRYVILLE             38.67N 78.25W
08/05/2005                   RAPPAHANNOCK       VA   TRAINED SPOTTER

            2-3 FEET DIAMETER TREE DOWN IN SPERRYVILLE

&&

ROSA