DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0743 AM CDT SAT SEP 08 2007
VALID 081300Z - 091200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER A SMALL PART OF SRN NY/NRN
PA AND NEW ENGLAND...
...SYNOPSIS...
BROAD LOW AMPLITUDE TROUGH WILL PERSIST FROM THE NRN RCKYS TO THE
UPR MS VLY THIS PERIOD...N OF ELONGATED RIDGE EXTENDING FROM THE SRN
RCKYS ACROSS THE LWR MS VLY TO THE MID ATLANTIC CST. STRONG IMPULSE
THAT CROSSED THE UPR GRT LKS YESTERDAY WILL CONTINUE ENE INTO ERN
QUEBEC AS ASSOCIATED COLD FRONT SETTLES SLOWLY S/SE ACROSS NEW
ENGLAND...THE LWR OH VLY AND THE SRN PLNS.
FARTHER W...IMPULSE NOW IN CNTRL MT SHOULD CONTINUE E INTO NRN MN
AND WEAKEN TONIGHT/EARLY SUNDAY AS UPSTREAM DISTURBANCE IN CNTRL BC
AMPLIFIES SE INTO THE NRN RCKYS. FAIRLY STRONG FRONT WITH MT SYSTEM
WILL NOSE S ACROSS WRN PORTIONS OF SD AND NEB...WHILE ERN PART OF
SAME BOUNDARY REMAINS MORE DIFFUSE AND MOVES SLOWLY S ACROSS THE UPR
MS VLY/UPR GRT LKS.
...SRN NY/NRN PA INTO CNTRL/SRN NEW ENGLAND...
MODERATE HEATING WILL OCCUR S OF COLD FRONT AND DEFORMATION CLOUD
BAND ACROSS PARTS OF THE NERN STATES TODAY...WHERE RECORD OR
NEAR-RECORD MAX SFC TEMPERATURES MAY OCCUR. BUT MID LVL LAPSE
RATES...LARGE SCALE FORCING FOR ASCENT AND CONVERGENCE WILL BE WEAK
AS LEAD UPR IMPULSE LIFTS RAPIDLY ENE INTO QUEBEC. A BAND OF SCTD
TO BROKEN STORMS SHOULD NEVERTHELESS FORM AHEAD OF FRONT AND
AFOREMENTIONED CLOUD BAND OVER PARTS OF NEW ENGLAND...NY AND PA.
GIVEN MLCAPE OF 1500 TO PERHAPS TO 2000 J/KG...MODEST UNIDIRECTIONAL
WSW FLOW SHOULD SUPPORT MULTICELLULAR CLUSTERS THAT COULD YIELD A
FEW SPOTS OF LOCALLY DAMAGING WIND.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
449 AM EDT SAT SEP 8 2007
.NEAR TERM /UNTIL 2 PM THIS AFTERNOON/...
***RECORD HEAT LIKELY AROUND 2-3PM AT BOS BDL***
CLOUD PATCHES AS SEEN ON IMAGERY AND OBS NW MA...MONADNOCKS...LI AND
CC CANAL WILL RAPIDLY DISSIPATE AFTER SUNRISE REVEALING FULL SEARING
SUN WITH HAZE ALOFT.
MWN WB OF 55F AT 3AM PLUS 83 DEG TEMP AT SYR SUGGESTS RECORD HEAT FOR
BDL/BOS TODAY WITH 93-97F LIKELY IN THE MHT-ASH-BVY-BOS CORRIDOR AND
92-95 CEF-BDL. 06Z NAM HAS 2M TEMP AT BOS OF 93-94 AND BDL CEF 92-93.
WE NORMALLY ADD ABOUT 3-5F TO THESE TEMPS ON SW FLOW AND 5 TO 6F ON
WNW SFC WIND. BLV ITS SAFE TO EXPECT 96 AT BOS AND 95 AT BDL/CEF TDY.
WE WILL NEED TO THINK OF UPGRADING TO A HEAT ADVY FOR ESSEX COUNTY
...MIDDLESEX COUNTY SUFFOLK COUNTY MASS AS WELL AS ERN HILLSBOROUGH
IN OUR 10AM REVIEW.
CURRENT HI FCST TO 99F VCNTY LWM TODAY. NO HEAT ADVY BUT CLOSE CALL.
CAPE COD AREA SHOULD SEE GUST 24-28KTS THIS AFTN.
&&
.SHORT TERM /NOON SATURDAY THROUGH SATURDAY NIGHT/...
-- Changed Discussion --
***RECORD HEAT MAY GIVE WAY TO ISOLATED SVR STORMS NRN MASS LATE IN
THE DAY THEN TEMPS 25 DEGS COOLER IN NE MASS ON SUNDAY AFTN COMPARED
TO THIS AFTN***
SVR RISK...PLS SEE SPC DISCUSSION. WE ARE RESTRICTING SVR POTENTIAL A
LITTLE FURTHER N IN THE PRIMARY KI AXIS WITH INITIATION BY THE CFP.
TT NR 47. THERE WILL BE CHANGES TO THE FCST MIDDAY ON BEST AREA FOR
CONVECTION. SUFFICE TO SAY...ALREADY COOKING IN UPPER NYS...WITH
RECORD HEAT...POSSIBLE BRIEF INVERTED V SOUNDING...WILL MAXIMIZE
DOWNDRAFT POTENTIAL PROVIDED CONVECTION OCCURS WHICH IS NOT A GUARANTEE.
MARINERS BOSTON N SHORE SHOULD BE ALERT FOR A POSSIBLE NASTY LATE DAY
STORM. MWS/SMW POTENTIAL.
PWAT 1.75"+ AHEAD OF COLD FRONT...WOULD NORMALLY RESULT IN DEWPOINTS
LIKELY APPROACHING 70 BUT WITH DRY SFC SOILS...KEPT THE DEWS TRIM.
1 INCH OF R POSSIBLE IN 30 MIN WITH ISOLATED CELLS NRN MASS BUT NOT A
DROUGHT BUSTER.
COLD FRONT SAGS SOUTH INTO SNE SAT NIGHT BUT MAY END UP STALLING
NEAR MASS PIKE OVERNIGHT AS BEST PRESSURE RISES LIFT NE INTO THE
MARITIMES. WE DO EXPECT SCT SHOWERS/TSTMS TO LINGER INTO THE EVENING N
ZONES AS CDFNT MOVES INTO REGION.
THEN AS W FRONT LIFTS N LATER SUN...HEAVY SHOWERS POSSIBLE S NH WITH
TSTMS POSSIBLE ANYWHERE N CT W MASS SW NH.
|posted by Sam Lillo @ 9/08/2007 09:25:00 AM
