FXUS61 KBUF 092238
AFDBUF

AREA FORECAST DISCUSSION...MESOSCALE DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
638 PM EDT MON JUN 9 2003

AIRMASS STARTING TO STABILIZE ACROSS THE ENTIRE CWA AT THIS HOUR AS 
SETTING SUN IS STARTING TO SHOW ITS AFFECTS. AVG LI'S HAVE STABILIZED
TO BETWEEN ZERO AND +2...WHILE CAPE VALUES HAVE NOW DECREASED TO LESS 
THAN 400 J/KG THROUGHOUT.

VIS LOOP STILL SHOWS SOME FAIRLY THREATENING LOOKING BANDS OF MDT CU 
WORKING ACROSS THE REGION...AND A STEP OUTSIDE THE NWS OFFICE HERE 
REVEALED SOME ALTOCUMULUS MAMMATUS DURING THE PAST 15 MINUTES. STILL 
SOME INSTABILITY TO DEAL WITH...BUT WE SEEM TO PAST OUR PRIME.

LATEST LOOK AT REGIONAL DOPPLERS SHOW ONE "FRISKY" SHOWER OVER IAG 
COUNTY...THAT HAS SINCE WEAKENED AND IS MOVING ACROSS TONAWANDA CREEK 
TOWARDS GENESEE COUNTY. RADAR PCPN ESTIMATES OF A QUARTER TO HALF 
INCH OF RAIN CORRESPOND TO THIS CELL OVER SW IAG COUNTY FROM EARLIER 
IN THE HOUR.

THE ACTIVITY OVER THE FINGER LAKES STILL LOOKS THREATENING ON 
SATELLITE...BUT AS MENIONED...MSAS AND LAPS DISPLAYS SHOW ATMOSPHERE 
IS BECOMING A BIT MORE STABLE AND LESS MOISTURE CONVERGENCE BEING 
SHOWN. WILL STILL MONITOR FOR ANY ISOLATED ACTIVITY THROUGH 
NIGHTFALL.

PREVIOUS AFD LEFT INTACT BELOW.....

AVAILABLE INSTABILITY...AS LAPS AND MSAS ANALYSES SHOWING LIFTED 
INDICIES AS LOW AS -2C JUST WEST OF THE FORECAST AREA IN 
PROGRESSIVELY COOLER TEMPERATURES ALOFT...RESULTING IN SCATTERED 
SHOWERS...WITH THE BEST COVERAGE IN THE BETTER CONVERGENCE OVER THE 
NIAGARA PENINSULA.  AS DIURNAL HEATING DIMINISHES...LOOKING FOR THE 
CHANCES FOR SHOWERS TO DIMINISH AS WELL AND REMAINING EVENING CLOUDS 
TO ERODE.  EVEN INTO MICHIGAN DEW POINTS ARE IN THE 50S...SO 
ANTICIPATING MINS OVERNIGHT TO STAY MOSTLY IN THE 50S WITH NEAR 50 
EAST OF LAKE ONTARIO AND INTO THE 40S IN PARTS OF THE SOUTHERN 
TIER.  NGM MOS...NORMALLY GOOD WITH FOG...HAS NO MENTION OF FOG BUT 
WILL FORECAST SOME PATCHY FOG IN THE SOUTHERN TIER VALLEYS OVERNIGHT 
DUE TO DEW POINTS STAYING UP OVERNIGHT AND THE RECENT SHOWERS.

MODEL SOUNDINGS FROM THE ETA SHOW WESTERN AND CENTRAL NEW YORK TO BE 
CAPPED FOR THE DAY TUESDAY...DESPITE AN INCREASE IN ISENTROPIC LIFT 
ON THE 305K SURFACE OVER FAR WESTERN NEW YORK LATE IN THE DAY.  
APPROACH OF THE FRONT APPEARS SLOWER ON THE LATEST RUNS OF THE ETA 
AND GFS...AND THE USUALLY LIBERAL 0.01 QPF LINE ON THE AVN IS NOT 
EVEN INTO WESTERN NEW YORK BY 00Z WEDNESDAY.  INSTABILITY REMAINS 
LOW FOR THE DAY...AND WILL PLAN TO KEEP PRECIPITATION CHANCES OUT 
TUESDAY.

FRONT FINALLY MAKES IT TO NEAR BUFFALO AROUND 12Z WEDNESDAY...EXITING
THE FORECAST AREA WEDNESDAY AFTERNOON.  THE BEST UPPER SUPPORT IN 
TERMS OF PVA MOVES NORTH OF THE FORECAST AREA OVER CANADA...AND THE 
UPPER DIVERGENCE IS FORECAST TO DECREASE ON THE ETA AS THE FRONT 
APPROACHES LATE TUESDAY NIGHT...HOWEVER...THERE IS A DECENT INCREASE 
IN THETA-E VALUES AT BOTH 850MB AND 700MB TUESDAY NIGHT.  THE NOSE 
OF AN 80KT 300MB JET ALSO MOVES OVER WESTERN AND CENTRAL NEW YORK 
TUESDAY NIGHT INTO WEDNESDAY MORNING.  WITH WEAKENING CONVERGENCE...
CURRENT THINKING IS THAT A WEAKENING...NARROWING LINE OF SHOWERS AND 
THUNDERSTORMS WILL MOVE THROUGH WESTERN AND CENTRAL NEW YORK 
OVERNIGHT TUESDAY.  QPF VALUES ARE NOT TOO IMPRESSIVE...BUT THE MOS 
GUIDANCE POPS ARE ALL CREEPING UP FOR TUESDAY NIGHT VERSUS THE 00Z 
MODEL RUNS.  WILL HAVE LIKELY POPS TUESDAY NIGHT...WITH LINGERING 
CHANCES FOR SHOWERS MAINLY IN EASTERN AREAS WEDNESDAY.  SLOW 
PROGRESS OF THE FRONT...ALONG WITH INCREASING LIFT...CAPE...AND 
INSTABILITY WEDNESDAY AFTERNOON COULD RESULT IN A FEW SHOWERS 
REINTENSIFYING MAINLY IN EASTERN ZONES BEFORE MOVING INTO EASTERN 
NEW YORK DURING THE MID AND LATE AFTERNOON HOURS. 

CURRENT TREND OF THE GFS...AND EVEN THE MRF...IS TO HAVE THE LOW 
PRESSURE SYSTEM MOVING THROUGH PENNSYLVANIA LATE THURSDAY AND 
FRIDAY...AND THE ASSOCIATED FRONTAL BOUNDARY...FARTHER SOUTH.  WITH 
THE DEEPER MOISTURE EXPECTED TO BE MORE TO THE SOUTH...WILL REMOVE 
THE CHANCES FOR RAIN ESPECIALLY FOR JEFFERSON COUNTY FRIDAY.  FRIDAY 
CHANCES FOR RAIN MAY EVEN BE A LITTLE OVERDONE TOWARD LAKE ONTARIO 
BASED ON THE LATEST GFS...WHICH HAS DEEP MOISTURE ONLY ABOUT INTO 
THE SOUTHERN TIER LATE THURSDAY NIGHT AND FRIDAY.  WILL CONTINUE 
WITH CONTINUITY FOR NOW DUE TO SOME UNCERTAINTY IN THE MODEL TRACK 
OF THE LOW AND THE TIGHT NORTHERN GRADIENT ON THE GFS FROM HEAVY 
RAIN OVER PENNSYLVANIA TO LITTLE OVER MUCH OF THE BUF CWFA.  HIGH 
PRESSURE BUILDS IN FOR THE WEEKEND...WHICH IS SUPPORTED AT LEAST 
INTO THE EARLY PART OF THE WEEKEND BY EXTRAPOLATION OF THE CANADIAN 
GLOBAL MODEL.  NCEP EXTENDED DISCUSSION ALSO LEANS TOWARD A FARTHER 
SOUTH SOLUTION...WHICH IF IT HOLDS TRUE SHOULD ALLOW FOR A DRY 
WEEKEND.  UPPER LOW THAT IS CURRENTLY FORECAST TO DEVELOP OVER THE 
MIDDLE PART OF THE U.S. STAYS THERE FOR THE WEEKEND.  PATTERN SHIFT 
OF DEEPENING TROUGH IN THE WEST AND INCREASING HEIGHTS IN THE 
EAST...ALONG WITH ANTICIPATED SOUTHEAST SURFACE FLOW BY EARLY NEXT 
WORKWEEK...COULD GET TEMPERATURES FINALLY INTO THE 80S BY THE END OF 
THIS FORECAST PERIOD.

.BUF...NONE.

$$

RSH/DJF