Heavy Rain in New Jersey, April 12 to 13, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
315 PM EDT MON APR 12 2004

WE WILL BE ISSUING A FFA WITH THIS FCST PKG AS THE MDLS HAVE BEEN
CONSISTENT ON BRINGING HVY RAIN ACRS OUR CWA DURG THE DAY ON TUE.
WHL IT DOES NOT APR WE WILL GET INTO THE CLOUD FREE PART OF THE WARM
SECTOR...TSRAS SHLD ROLL ACRS THE RGN TMRW ENHANCING OUR PTNL FOR
HVYR RAIN. EVENT TOTALS SHLD BE AVGG BTWN 1 TO 2 INCHES AND COULD BE
UP ARND THREE INCHES IF TSRAS OCR IN SCTD LOCNS. FLOODING PBLMS
BEGIN WITH ABT 2 IN STORM TOTALS AND A 2 TO 3 INCH BASINWIDE EFFECT
WILL CAUSE SGFCNT RISES...IF NOT FLOODING...ON ALL AREA STREAMS AND
RIVERS.

WE WILL BE LEANING TWD THE ETA FOR THE FIRST 36HRS AS THE GFS HAS
ACTUALLY TRENDED TWD ITS SOLN FROM YDA/S 12Z RUN. THE GFS SFC LO
24HR PROG IS NOW ABT 300 MILES FTHR S TUE MRNG CLOSER TO THE PATH
THE ETA HAS HAD ALL ALG. IT GETS MURKIER AFT WED NGT AS THE ETA
CLOSES THE LOW ALF AND HAS THE SLOEST EWD SOLN THEREAFTER. IT IS
SLGTLY FASTER THAN THE ITS 00Z RUN...BUT NOT THAT MUCH SLOR THAN THE
ECMWF. THE OTHER MDLS...GFS INCLUDED...HAVE BCM FASTER AND MORE
PROGRESSIVE AND WE HAVE OPTED BY THU NGT TO SPLIT THE DIF.

SHORTER TERM TNGT THRU TUE NGT - NOT MUCH MDL DISAGREEMENT TNGT AS
MANY INGREDIENTS COMING TOGETHER FOR A SOAKING RAIN. ONE COULD
ALMOST PICK ANY MET PARAMETER (LLJ, STG LLVL WAA, GREAT ISENTROPIC
LIFT, DVRG ALF) TO SUPPORT IT IF LOOKING AT DOWNSTREAM RADARS WASN/T
ENUF. MDL QPFS GENERALLY BTWN 1/2 INCH AND INCH THRU 12Z WITH THE
CAN GEM SLGTLY WETTER. SO WE SEE NO CHG TO PREV FCST OF RAIN. THIS
WAA SHOT UNFORTUNATELY WILL PRIME THE AREA FOR WHAT MIGHT COME LATER
IN THE DAY ON TUE. GFS MOS NOW THAT ITS PARENT SOLN HAS THE LOW FTHR
TO THE SE SEEMS MORE IN LINE WITH ONLY A BEGRUDGING RISE OF TEMPS
TWD MRNG.

WHL MDL DIFS CONT TO EXIST WITH RESPECT TO THE AXIS OF HVY RAIN (NJ
VS PA)...THEY ALL HAVE PART OF OUR CWA AS THEIR FAVORED AREA. THERE
SEEMS TO BE A GENERAL AGREEMENT THAT THE GREATEST INSTAB ON TUE DAY
WILL BE TO THE LEE OF THE APLCHNS IN VA AND NC AND THIS CONVECTION
IN A WEAKENED FORM SHLD MOVE NEWD ACRS OUR CWA. THE ETA SEEMS TO
FAVOR THE ERLR PART OF THE DAY...WHL THE GFS LATER IN THE AFTN.
LOGICALLY SPEAKING THE LATTER PART WOULD MAKE MORE SENSE GIVEN THE
RAIN COOLED AIR HAS TO BE MODIFIED AND WARMED EVEN TO OUR SE. SO TO
THAT END WE WILL LEAN TWD THE GFS. THE INSITU COOL AIR DAMG WILL
PBLY SAVE THE BULK OF OUR CWA FROM A SVR WX THREAT AS WE SHLD RMN
LONGER IF NOT COMPLETELY IN THE MARINE/WAA RAIN INDCD AIR MASS.
THERE IS ENUF INSTAB ABV THIS INVERSION TO MAINTAIN THE THUNDER AND
IF NOT THAT AT LEAST SOME CONVECTIVE PCPN. WITH PWATS OF ABT 1.5
THIS CAN EASILY TRANSLATE INTO LOCALLY HVYR DOWNPOURS. ALSO CONCERN
RMNS THAT THE VEGETATION IS BEHIND SCHEDULE. MOS MAX TEMPS ARE
PRETTY TIGHTLY CLUSTERED AND WON/T BE STRAYING...WE WENT SLGTLY BLO
THEM OUT OF RESPECT FOR THE RAIN COOLED AIR.

THE FCST MDLS ARE A BIT FASTER IN ENDING THE HVYR PCPN THREAT EITHER
BY EVE OR DEFINITELY IN THE EVE. CUR FCST ALRDY REFLECTS THIS AND WE
WON/T BE CHANGING IT MUCH. IN SPITE OF MDL DIF BEYOND TUE
NGT...THERE IS STILL GENERAL AGREEMENT THRU THIS TIME PERIOD. THE
DEEP TROP CONNECTION IS EXPECTED TO BE E OF US BY THEN AND DEPENDING
UPON WHICH MDL ONE CHOOSES...WE MIGHT EVEN GET DRY SLOTTED. WE HAVE
LEANED TWD THE COOLER ETA/GFS MOS WHICH S/B CORRECT EITHER BECAUSE
OF A WEAK ONSHR FLOW AND/OR COOLING FROM THE HVYR RAIN.

LONGER TERM - WED THRU MON - MDL DIFS START TO CROP ATTM WITH THE
ETA/ECMWF CLOSING OFF THE LOW AND PROGRESSING IT MORE SLOWLY THAN
THE GFS/UKMET/CAN SEF. THE DIFS HAVE ACTUALLY INCREASED FROM YDA.
THE GENERAL TREND EVEN WITH THE ETA/ECMWF IS A BIT MORE
PROGRESSIVE...SO WE WILL COMP BTWN THE TWO. NO MATTER WHICH MDL IS
PICKED FOR WED...THERE S/B SUFFICIENT MSTR AND INSTAB FOR SCTD SHRAS
...AND BASED ON THE ETA LI TSRA. GFS MOS MAX TEMPS LOOK TOO WARM
UNLESS THE WHL SYS PROGRESSES MUCH SLOWER THAN CUR EXPECTED. BEYOND
THAT WE WILL CARRY A CHC OF A MRNG SHRA THU AND GO DRY AFTER THAT.
SHLD BE PRETTY QUIET AFT THAT. LATEST 12Z GFS LOOKS MORE IN LINE
WITH THE CAN SEF AND ECMWF WITH BRINGING A BACKDOOR INTO NY STA ON
THE WEEKEND. ATTM THIS DOES NOT SAG FAR ENUF S TO AFFECT US AND IS
IN LINE WITH MDL CONSENSUS FROM YDA. ONLY MNTN OF PCPN WILL BE IN
THE EVE MON FAR N. BY THEN WITH AN OFSHR FLOW AND H8 TEMPS ARND
10C...WE SHLD SEE TEMPS IN THE 70S AWAY FROM THE CST AND SANS ELEV
LET SPRING REALLY BEGIN.

MARINE...SCA CONT FOR THE CST AND LWR DE BAY.

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH FOR TUE AND TUE NGT PAZ054/055/060>062/067/071.
NJ...FLOOD WATCH FOR TUE AND TUE NGT NJZ001/007>010/012/013/015>019.
DE...FLOOD WATCH FOR TUE AND TUE NGT DEZ001.
MD...FLOOD WATCH FOR TUE AND TUE NGT MDZ008.
MARINE/OCEAN...SCA.
MARINE/DEL BAY...SCA LOWER BAY.

TFG

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
442 AM EDT MON APR 12 2004

DEZ001>004-MDZ008-012-015-019-020-NJZ001-007>010-012>027-PAZ054-055-
060>062-067>071-121100-
ATLANTIC NJ-ATLANTIC COASTAL CAPE MAY NJ-BERKS PA-BUCKS PA-CAMDEN NJ-
CAPE MAY NJ-CARBON PA-CAROLINE MD-CECIL MD-CHESTER PA-
COASTAL ATLANTIC NJ-COASTAL OCEAN NJ-CUMBERLAND NJ-DELAWARE PA-
DELAWARE BEACHES DE-EASTERN MONMOUTH NJ-GLOUCESTER NJ-HUNTERDON NJ-
INLAND SUSSEX DE-KENT MD-KENT DE-LEHIGH PA-MERCER NJ-MIDDLESEX NJ-
MONROE PA-MONTGOMERY PA-MORRIS NJ-NEW CASTLE DE-NORTHAMPTON PA-
NORTHWESTERN BURLINGTON NJ-OCEAN NJ-PHILADELPHIA PA-QUEEN ANNES MD-
SALEM NJ-SOMERSET NJ-SOUTHEASTERN BURLINGTON NJ-SUSSEX NJ-TALBOT MD-
WARREN NJ-WESTERN MONMOUTH NJ-
442 AM EDT MON APR 12 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL AND
SOUTHEAST PENNSYLVANIA...DELAWARE...THE NORTHERN MARYLAND
EASTERN SHORE...AND NEW JERSEY EXCLUDING THE FIVE NORTHEAST
COUNTIES.

.DAY ONE...TODAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...

ON TUESDAY...THE CONTINUED RAINFALL WHICH SHOULD BE HEAVY AT
TIMES...COULD ALLOW FLOODING TO DEVELOP ON SMALLER STREAMS AND IN
HIGHLY URBANIZED AREAS. ADDITIONALLY...THUNDERSTORMS WILL BE
DEVELOPING AND SOME OF THE THUNDERSTORMS COULD HAVE STRONG GUSTY
WINDS AND HAIL.

ON WEDNESDAY...THUNDERSTORMS COULD DEVELOP IN THE AFTERNOON.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED TODAY BUT SPOTTER ACTIVATION IS
POSSIBLE ON TUESDAY.

STAUBER