Damaging Wind in Pennsylvania, June 22, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1125 AM EDT FRI JUN 22 2001

HAVE REISSUED ESF FOR FLOOD THREAT AND POSSIBLE SEVERE
THUNDERSTORMS. HAVE ALSO CLEANED UP ZONES. NO UPDATES WERE
NECESSARY. RK

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MDLS ARE IN PRETTY GOOD AGREEMENT WITH THIS FCST PKG AND DO NOT
SHOW MUCH CHANGE FROM THE PREV FCST OR MDL RUNS. DEEP TROF ACRS THE
OHIO VLY WILL WKN AND LIFT NEWD TDY. CDFNT IN WRN OH SHLD REACH WRN
PA THIS EVE AND JUST W OF OUR CWA SAT MRNG B4 CLRG THE CST BARELY ON
SUN MRNG. BY THEN STG WRLYS ON TOP OF H5 RDG IN LWR ROCKIES
EFFECTIVELY CREATES A CUT-OFF W OF US ON SUN AND THEN MEANDERS AD
NAUSEUM THRUT MOST OF THE EXTDD PART OF THE FCST. IF THERE IS ANY
SUBTLE CHG...THE TROF MOVES SLGTLY FTHR E THAN LAST NGT/S RUN AND
THIS IS REFLECTED IN SOME DRIER AIR GETG INTO THE FCST AREA ON SUN.
LTR TAFTN AND TNGT IS ROUND 3 OF SVR WX/ROUND 2 OF HVY CPN PTNL.
THIS SHIFTS EWD INTO NJ/DE ON SAT.

FOR TDY...ONGOING CONVECTION OVER THE D.C. AREA IS TIED INTO THE
BACK END OF A SHRTWV. AIR MASS IS UNSTABLE ABV BNDRY LYR TO SUPPORT
THUNDER AND LLVL WAA DOESN/T HURT EITHER. THIS WILL COMPLICATE
WORDING OF FCST SINCE WE DON/T ANTICIPATE PCPN DISPTG. BLV FROM THE
LEHIGH VLY NW WE/LL WORD ZONES WITH LIKELY POPS W/O ANY TIMING. ARND
PHL METRO AREA WILL MAKE A LAST MINUTE DECISION...BUT MAY CARRY A
CHC ERLY WITH TSRAS LIKELY AGN LATE TAFTN. FTHR TO THE E WE/LL JUST
CARRY A CHC LATE IN THE DAY (MIGHT NOT ARRIVE TIL THIS EVE).
ECHOES OVR THE NEARBY ATLC APR TO BE FALLING FROM CLR SKIES.
GREATEST INSTAB HAS SHIFTED W OF THE DE AND IT DOES NOT APPEAR THE
SEA BREEZE FNT WILL BE AS ACTIVE AS YDA. IN ADTN...A STG NVA RDG IS
FCST TO MOVE ACRS THE SERN HALF OF OUR CWA DURG THE MAX DAYTIME
HEATG. THIS DID SUPPRESS THE CONVECTION OVR THE WRN CAROLINAS YDA.

OVR THE WRN HALF OF OUR CWA...THE WX WILL BE A BIT MORE INTERESTING.
ETA FCSTG CAPES TO ABT 2500J TAFTN. IT DOES NOT LOOK AS OVERDONE AS
LAST FEW DAYS WITH ITS LL MSTR. DEWPTS IN LWR 70S APR REACHABLE.
TTS ARE FCSTD TO BE IN THE MID 40S...BUT THAT DID NOT STOP THE
CONVECTION YDA. THE WIND FIELD WILL BE A BIT STGR...GRANTED NOT
SPECTACULAR BUT COULD HAVE A 25 KT LLJ OVR WRN PARTS OF OUR CWA DURG
THE MAX OF DAYTIME HEATG. ETA FCSTG A 15C DROP OF EQUIV PTNL TEMP
WITH HEIGHT TDY...DOWN FROM YDA/S 20...BUT STILL AT THE LOW END OF
THE SPECTRUM FOR PULSE/MULTICELL SVR. WOULD NOT HAVE THOUGHT THERE
WOULD HAVE BEEN SVR IN OH GIVEN HOW MOIST THE AIR MASS WAS LAST EVE.
THIS IS PA/S AIR MASS TAFTN. UPSHOT AGREE WITH SPC/S ACCESSMENT FOR
A LOW GRADE SLGT RISK FOR WRN PART OF OUR CWA...BORDERLINE PULSE SVR
SUPERIMPOSED WITH SLGTLY STGR WINDS ALF. SERLY FLOW WILL PRODUCE
LLVL VEERING WITH HEIGHT...BUT WIND FIELD (AND FCSTD HEL VALUES)
DOES NOT APR STRONG ENUF TO SUPPORT ROTATING TSRAS (LOCAL
ENHANCEMENTS ASIDE). PSBL FLY IN THE OINTMENT WITH ALL OF THIS WILL
BE HOW QUICKLY SKIES WILL CLR ACRS CNTRL PA/WRN MD/WV.

DUAL THREAT IN PA FOR BOTH STGR STORMS AND HVY RAINFALL. MDLS ARE
KEYING ON LOCNS JUST W OF CWA FOR THE TORRENTIAL DOWNPOURS. QUES
WILL BE HOW QUICKLY CAN THIS CONVECTION GET INTO OUR CWA LT THIS
AFTN. IF IT COINCIDES BETTER WITH DAYTIME HEATG...SOME TORRENTS
COULD OCCUR. PWATS ARE STILL AOA 1.50 ALTHO THE STATED WIND FIELD
WILL BE STGR. ATTM WE/LL ISSUE A COMBO SVR/HVY RAIN PTNL SPS WITH
THE MRNG PKG AND LET THE DAY SHIFT SEE HOW WELL SKIES HAVE CLRD AND
HOW STG THE STORMS GET.

WK SHRT WVS CONT TO RIDE NEWD ALG THE TROF AND PASS ACRS THE WRN
PART OF OUR CWA TNGT. ENTR RGN OF H2.5 JET ALSO APCHS THIS PART OF
OUR CWA. PRBL REASONS WHY HVYST MDL QPF RMNS W OF THE DE RVR. NOT
TOO MUCH TO CHG FROM PREV PKG...WE/LL WORD LIKELY POPS (ALG WITH
PSBL HVY DOWNPOURS) FROM THE I95/TURNPIKE CORRIDOR NW AND CHC POPS
FTHR TO THE S WHERE CWA RMNS NESTLED BTWN SHRT WV TO THE W AND ONE
FCSTD TO GO FROM NC CSTL WATERS INTO LI/NEW ENG.

CDFNT JUST W OF THE CWA SAT MRNG...BUT WILL TAKE A GOOD PART OF 24
HRS TO CLR THE/DISPT ALG THE CST. WE WILL CARRY CHC POPS ACRS OUR
NWRN ZNS AND LIKELY POPS FTHR TO THE SE AS THE FNT WILL HAVE MORE
TIME TO INTERACT WITH THE DAYTIME HEATG. THIS COULD BE THE DAY FOR
HVYR PCPN FOR NJ/DE CTYS. AS FAR AS SVR GOES....ALTHO THE STGST WIND
FIELD OF THE LAST FEW DAYS WILL BE AOA 700MB...FCSTD CAPES (BLO 2J)
AND LI (ABT -4) ARE MORE MARGINAL. IT WILL PBLY DEPEND UPON HOW
QUICKLY SKIES CLR AGN ON SAT IF WE GET CLS TO SVR LIMITS. W/O A STG
SHRT WV ALF...WK TTS AND BLO THRESHOLD EQUIV THETA E TEMP DROP
ALF PRFR TO EMPHASIZE THE HVY RAIN VS THE STG GUSTY WINDS ATTM.

WILL ACTUALLY CARRY A DRY FCST FOR OUR NWRN ZNS FOR SAT NGT. WILL
CONT THE CHC FOR OUR SERN ZNS. COORD WITH HPC AND IT DOES APR AVN
SUFFERING FROM GRID SCALE CONVECTIVE FEEDBACK AS THERE/S NO RUN TO
RUN CONT AND ITS SISTER CAN SEF IS NOT CARRYING WHOPPING PCPN
BULLSEYE THRU NJ. IN LIGHT OF THIS AND THE SLGTLY MORE EWD POSN OF
THE CDFNT WILL REMOVE THE MNTN OF PCPN FOR SUN ON THE EXTDD...BUT
LEAVE THE REST AS IS. WITH H5 LOW FCSTD TO BE PUSHED WWD BY BUILDING
RDG IN THE WRN ATLC...MSTR ALG WITH PCPN SHLD RETURN BY MON.

YDA/S MEANDERING TSRA/S PRODUCED ABT FIVE REPORTS OF SVR WX AND SOME
WHOPPING PCPN TOTALS. SVR TSRAS FORMED ON THER CSTL FNT...A RARITY
FOR US. DOPPER STORM TOTAL ESTIMATES EXCEEDED 6 INCHES IN NRN BERKS
CTY AND SEEMS RSNBL GIVEN THE 4 INCH IN 20 MIN REPORT FROM
GALENA/KENT CTY DE.

MAR: SOME FOG PBLMS IN ERLY FLOW...OTRWISE WINDS AND SEAS S/B BLO
SCA CRIT.

TU FOR COORD BGM/HPC/SPC...HAVE A GREAT DAY AND WEEKEND

TFG