Flooding in Maryland, January 1, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1045 AM EST WED JAN 01 2003

LATEST RADAR AND SATELLITE IMAGERY SHOWS MAIN AREA OF MDT TO HVY
RAIN LIFTING NWD ACROSS CWA. PRECIP OVR FAR SRN ZONES IS MORE
SCATTERED IN NATURE. WILL WORD PRECIP AS SHRAS SRN ZONES WHERE
PRECIP IS MORE SCATTERED. WILL MENTION TSRA POSSIBLE THERE TOO WHERE
SOME BREAKS ARE POSSIBLE. 12Z RUC2 FCST SOUNDINGS SHOW TT
OF 55 WITH LIFTED AND SHOWALTER BECOMING NEGATIVE AND CAPES 200-400
J/KG AHEAD OF UPPER LOW.

ROSA

...SHORT TERM...TODAY THRU THU...

STRONG LOW PRES SYSTEM RAPIDLY APPROACHING CWA FROM SW AND PLENTY OF
PRECIP WILL ACCOMPANY IT. DURING THE PRE DAWN HOURS...FRONTOGENESIS
ASSOC WITH 850MB WARM FRONT AHEAD OF SYSTEM CAUSED SOME LIGHT PRECIP
TO FALL OUT OF A MID DECK N 1/3 CWA. THIS WAS JUST THE PRECURSOR TO
THE STRONG LIFT THAT WILL BE ACCOMPANYING LOW TODAY. PRECIP WATER
VALUES REACH 1.5 INCHES THIS AFT AND STRONG UL DIV...500-700MB PVA
AND 850MB UPSLOPE UP TO 40KTS WILL BE ABLE TO SQUEEZE OUT ABT AN
INCH OF RAIN BETWEEN 12Z AND 02Z.

LOW MOVES QUICKLY NE OF CWA BY 06Z...TAKING CONCENTRATED FORCING
WITH IT. HOWEVER...IT LEAVES PLENTY OF LOW LEVEL MOISTURE AND COLD
AIR DAMMING IN ITS WAKE. WITH RIDGING BUILDING IN ALOFT AHEAD OF 2ND
LOW...WEAK OVERRUNNING SETS UP. THIS SCENERIO GIVES THREAT OF -DZ OR
-FZDZ THU MORN...ALTHOUGH PRECIP AMNTS WILL BE VERY LIGHT.

THU AFT...COLDER AIR SHOWS UP ALOFT AS RIDGING PUSHES E OF CWA. THIS
IN COMBO WITH SOME LIFT STARTING TO REACH W CWA FROM NEXT LOW WILL
ALLOW PRECIP TO CHANGE OVER TO SLEET OR -SN IN NW ZONES. IT LOOKS
LIKE REST OF CWA WILL NOT SEE LIFT UNTIL THU NITE SO EVEN THOUGH
SOUNDING WILL START TO COOL ALOFT...SUPERCOOLED DROPLET PROCESSES
WILL PREVAIL...KEEPING PRECIP IN LIQUID FORM. WILL KEEP PRECIP AS
-DZ/-FZDZ REST OF CWA THU AFT.

MMARGRAF

.LATER PERIODS...BASIC MDL CONSENSUS THRU WKND. PTTN LOOKS TO BE AN
ACTV ONE...AND QSTN IF EACH WAVE IS GETTING ITS DUE...OR IF MASSIVE
FEEDBACK PRESENT. FOR THIS REASON...WL BE MAKING ONLY SMALL STEPS IF
ANY CHG AT ALL.  W/ SUCH AN ACTV PTTN /WAVES EVRY 36 HRS/...THESE
SVRL WVS MAY MERGE INTO ONE GLOOMY STRETCH FM A PUBLIC PERSPECTIVE.

TIMING ON 2ND S/WV LT THU/FRI HAS BEEN CONSISTENT FOR SVRL DAYS NOW.
STRNG OMEGA FIELD PRSNT OVR CWFA...SPCLY ONCE CSTL SFC LOW TAKES OVR
FRI. MSTR CERTAINLY PRESENT SFC-H7 FOR LIFT TO ACT UPON. SO...FEEL
COMFY BUMPING POPS UP TO LIKELY W THU NGT..EVRYWHR FRI. NOW...FOR
PTYPE-- THE BIG MYSTERY.  00Z RUN COMING IN A PINCH COLDER...LEANING
MORE TWD SNW. COLD AIR DAMMING PRESENT...WHICH SYNOPTIC MDLS ALWAYS
ERIDE AWAY TOO QUICKLY. THRML PROFILES ALSO SUGGEST A COLD SOLN.
HWVR...TKNS SCHEMES HINT AT WARMTH ALFT...W/ LIQUID PCP SERN THIRD.
THIS LYR CAN BE SPOTTED IN SDNGS AT 800 MB...BUT NEVER CROSSES 0C
ISOTHERM. BOURGOIUN /ENERGY/ METHOD PROBABLY BETTER AT DISCERNING
PTYPE...BUT W/ SFC AND/OR H8 LOWS POTENTIALLY TRACKING OHD...WOULD
RATHER NOT GET TOO SPECIFIC IN FCST YET.  SUSPECT WRN HALF WUD
REMAIN ALL SNW...A SMALL ERN/SERN PORTION ALL RAIN...WITH SOME SORT
OF TRANSITION ZN IN BTWN. WL MAKE EASY COMMITMENT TO ALL SNW W OF
BLURDG AS LOW PULLS AWAY FRI NGT...AND LET THE REST STAND AS IS.

SHSN IN WRN MTNS SAT...THEN A TRANSITORY PD BEFORE NXT S/WV SUN.
NEW GDNC SUGGESTING THIS TOO WL DROP PCPN...AND THIS TIME IS WUD BE
ALL SNW. HWVR...SINCE THIS IS THE THIRD STORM THE MDLS ARE
ATTEMPTING TO RESOLVE...I/VE OPTED TO LET DAYSHFT HNDL IT. I/VE
INCRSD CLDCVR FOR THE WKND AS FLW NEVER REALLY DVLP GOOD DWNSLOPING
TO SCOUR OUT PLENTIFUL LLVL MSTR.

SMALL TWEAKS WERE MADE TO TEMPS...BUT OVRALL STAYED PRETTY CLOSE TO
GFS.  HV MADE NO CHGS TO FCST MON-TUE.

HTS

.LWX...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SCA CHSPK BAY AND TIDAL PTMC COBB ISL TO SMITH PT.

DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-025>031-036>042-
050>057-WVZ048>055-012215-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1110 AM EST WED JAN 1 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MARYLAND WEST OF THE CHESAPEAKE
BAY AND EAST OF GARRETT COUNTY...THE DISTRICT OF COLUMBIA...NORTHERN
VIRGINIA...THE NORTHERN AND CENTRAL SHENANDOAH VALLEY...AND THE
EASTERN PANHANDLE OF WEST VIRGINIA.

.DAY ONE...TODAY

A RUMBLE OF THUNDER IS POSSIBLE THIS AFTERNOON IN THE VICINITY OF
CHARLOTTESVILLE AND FREDERICKSBURG.

SKYWARN ACTIVATION IS NOT ANTICIPATED.

.DAYS TWO THROUGH SEVEN...

RAIN OR SNOW IS POSSIBLE AREAWIDE THURSDAY NIGHT AND FRIDAY.

MDZ002>007-VAZ021-025>031-042-WVZ048>055-021028-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
230 PM EST WED JAN 1 2003

...ANOTHER ROUND OF WINTER WEATHER MAY BE IN STORE FOR PORTIONS OF
MARYLAND...EASTERN WEST VIRGINIA...AND THE MOUNTAINS OF VIRGINIA FOR
THURSDAY NIGHT AND FRIDAY...

A COMPLEX WEATHER PATTERN CONTINUES TO EVOLVE. LOW PRESSURE IS
EXPECTED TO DEVELOP IN THE MISSISSIPPI VALLEY ON THURSDAY. THE LOW
WILL THEN TRACK THROUGH THE TENNESSEE VALLEY BEFORE MOVING OFF THE
VIRGINIA COAST FRIDAY EVENING. THIS WILL SPREAD EVEN MORE MOISTURE
INTO THE AREA.

WITH TEMPERATURES HOVERING CLOSE TO FREEZING THURSDAY NIGHT A MIX OF
RAIN AND SNOW IS EXPECTED IN THE APPALACHIAN MOUNTAINS. RAIN...
SLEET...AND SNOW IS LIKELY IN THE WESTERN SUBURBS OF WASHINGTON DC
AND BALTIMORE. ON FRIDAY MORE COLD AIR WILL BE DRAWN INTO THE
REGION...CHANGING THE PRECIPITATION TO ALL SNOW. SEVERAL INCHES OF
SNOW IS POSSIBLE AT THE HIGHER ELEVATIONS OF WESTERN
MARYLAND...NORTHERN VIRGINIA....AND THE EASTERN PANHANDLE OF WEST
VIRGINIA. FURTHER EAST IN MARYLAND...AN INCH OR TWO OF SNOW IS
POSSIBLE ALONG THE PENNSYLVANIA BORDER FROM FREDERICK COUNTY TO
HARFORD COUNTY.

STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER UPDATES ON THIS
DEVELOPING EVENT.

ABW