000
FXUS61 KBUF 230431
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1131 PM EST SUN NOV 22 2009

.SYNOPSIS...
HIGH PRESSURE EXTENDING FROM NEW BRUNSWICK TO THE OHIO VALLEY WILL 
KEEP DRY AIR OVER THE REGION THROUGH MONDAY. MOISTURE FROM A LOW 
MOVING UP THE MID ATLANTIC COAST WILL BRING A THREAT OF LIGHT 
RAIN TO AREAS FROM THE GENESEE VALLEY EASTWARD MONDAY NIGHT THROUGH 
TUESDAY MORNING. WEAK HIGH PRESSURE WILL FOLLOW LATER TUESDAY 
AND TUESDAY NIGHT. THE NEXT CHANCE OF SHOWERS WILL ARRIVE WEDNESDAY 
AS LOW PRESSURE MOVES INTO THE WESTERN AND CENTRAL LAKES. 
TEMPERATURES WILL BE ABOVE AVERAGE THROUGH THE MIDDLE OF THE WEEK 
BEFORE A COOLING TREND BY LATE WEEK.

&&

.NEAR TERM /THROUGH MONDAY/...
UPDATE AS OF 10 PM...GOING FORECAST IS IN GOOD SHAPE. ASIDE FROM
SOME MINOR TWEAKS NEEDED TO KEEP THINGS CURRENT...THE ONLY REAL
CHANGE TO THE FORECAST WAS TO ADD A MENTION OF SOME PATCHY FOG TO
ALL AREAS FOR THE OVERNIGHT AND EARLY HOURS OF MONDAY. WITH
GENERALLY CLEAR SKIES CONTINUING...A WEAK GRADIENT IN PLACE...AND
SFC T-TD SPREADS EXPECTED TO GET FAIRLY NARROW WITH NOCTURNAL
COOLING...WOULD NOT BE SURPRISED TO SEE SOME PATCHY FOG FORM JUST
ABOUT ANYWHERE OVERNIGHT.

MONDAY LOOKS TO BE ANOTHER FINE DAY THIS ATYPICAL NOVEMBER WITH 
PLENTY OF SUNSHINE AFTER ANY EARLY MORNING FOG BURNS OFF...AT LEAST 
FOR AWHILE. THE SUN WILL FADE BEHIND THICKENING CLOUDS FROM SOUTH TO 
NORTH DURING THE AFTERNOON AS A COMPLEX LOW PRESSURE SYSTEM OVER THE 
SOUTHEAST STATES LIFTS GRADUALLY NORTH...BUT THEN GETS SHEARED 
NORTHEAST AND EAST AND TAKES MOST IF NOT ALL OF ITS MOISTURE TO OUR 
SOUTH AND EAST (SEE SHORT TERM-MONDAY NIGHT). WILL INCLUDE SLGT CHC 
POPS CATT/ALLEG COS ONLY TWD SUNSET MONDAY. AS FOR TEMPS...WILL 
FOLLOW MILDER MAV/GFS ONES AS SEE NO REASON WHY WE WONT GET SIMILAR 
NUMBERS TO TODAY'S (L-M 50S) WITH SIMILAR 850/925MB TEMPS AND ENOUGH 
SUNSHINE.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
MONDAY NIGHT AND TUESDAY, AN EASTERLY FLOW OF ATLANTIC MOISTURE 
BETWEEN HIGH PRESSURE OFF THE CANADIAN MARITIMES AND LOW PRESSURE 
ALONG THE MID ATLANTIC COAST WILL SPREAD WESTWARD INTO MUCH OF THE
REGION WHILE A MID LVL SHORTWAVE MOVES NE ACROSS THE LOWER LAKES. 
THE COASTAL LOW IS EXPECTED TO MOVE TO CAPE COD BY TUESDAY 
AFTERNOON. THE QUESTION IS HOW FAR WEST TO BRING THE THREAT OF LIGHT 
RAIN. AT THIS TIME BOTH THE NAM AND GFS KEEP THE ACTIVITY TO THE 
EAST OF BUF, MNLY ACROSS AREAS FROM THE GENESEE VALLEY EASTWARD 
MONDAY NIGHT, AND AREAS EAST OF THE GENESEE VALLEY TUESDAY MORNING. 
THE THREAT SHLD END BY LATER TUESDAY ACROSS THE REST OF THE EASTERN 
PTNS OF THE CWA. 

WEAK HIGH PRESSURE SHLD FOLLOW TUESDAY AFTERNOON AND NIGHT. MODEL 
PROFILES SHOW PLENY OF LOW LVL MOISTURE HANGING OVER THE REGION 
UNDER THE WEAK HIGH SO DON'T EXPECT MUCH IN THE WAY OF ANY CLEARING.

ON WEDNESDAY, THE HIGH MOVES EAST OF THE AREA AND A SOUTHERLY FLOW 
OF INCREASINGLY MOIST AIR AHEAD OF LOW PRESSURE MOVING INTO THE
WESTERN LAKES BEGINS TO MOVE INTO THE REGION. THE NAM IS SLOWER
THAN THE GFS/ECMWF IN BRINGING IN THE MOISTURE WEDNESDAY. HAVE
GONE TOWARD THE GFS/ECMWF BRINGING IN THREAT OF SHWRS TO AREAS
FROM THE FINGER LKS WEST IN THE MRNG AND THEN REACHING AREAS EAST
OF LK ONTARIO DURG THE COURSE OF THE AFTERNOON.

TEMPS SHLD CONTINUE WITH ABV NORMAL HIGHS BOTH TUE AND WED. GENLY 
UPPER 40S TO LOWER 50S TUE AND LOW TO MID 50S WED. LOWS MON NGT SHLD 
RANGE FROM 35 TO 40 MONDAY NIGHT AND TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE NOW WELL ADVERTISED PATTERN CHANGE STILL APPEARS ON TRACK TO 
ARRIVE LATE WEEK. THE CURRENT PATTERN ACROSS THE NOAM SECTOR 
FEATURES A BROAD TROUGH OVER THE WEST WITH A RIDGE DOWNSTREAM OVER 
MUCH OF THE CENTRAL AND EASTERN PORTIONS OF THE CONUS. THE GEFS 
ENSEMBLE MEAN CONTINUES TO FORECAST THE NAO INDEX TO BECOME WEAKLY 
NEGATIVE BY THE END OF THE MONTH...WITH THE PNA INDEX TRENDING 
POSITIVE. IN THE MEAN...THIS SHOULD YIELD A COLDER PATTERN FOR THE 
GREAT LAKES AND NORTHEAST FOR THE LAST WEEK OF NOVEMBER INTO EARLY 
DECEMBER WITH A TROUGH FAVORED OVER THE EASTERN CONUS IN SUCH A 
PATTERN. THE INDICIES ARE NOT FORECAST TO BE PARTICULARLY STRONG
HOWEVER...SO NO DRAMATIC PATTERN CHANGE IS EXPECTED...RATHER A
TREND TOWARDS COOLER AND MORE SEASONABLE TEMPERATURES.

LOOKING AT THE DETAILS...THE LOW CONTINUES OVER THE CENTRAL LKS WED 
NGT INTO THANKSGIVING DAY BUT 850 TEMPS SHLD STAY WARM ENOUGH FOR 
THE PRECIP DURG THIS PERIOD TO BE IN THE FORM OF RAIN SHOWERS.
COLDER AIR BEGINS TO FILTER IN BEHIND THE LOW THANKSGIVING NIGHT 
WITH A CHANCE OF RAIN/SNOW SHOWERS. 

FRIDAY AND SATURDAY A DEEP LONGWAVE TROUGH WILL CARVE OUT IN THE 
LOWER LAKES AND OHIO VALLEY. THE LATEST 12Z GFS AND ECMWF BOTH 
DEVELOP A MAJOR COASTAL LOW...WITH THE GFS JUST A TAD FARTHER WEST, 
INLAND OVER NEW ENGLAND. BOTH OF THESE SOLUTIONS WOULD SUGGEST THE 
POTENTIAL FOR SIGNIFICANT QPF FOR CENTRAL AND EASTERN NY. PRECIP 
TYPE WILL BE A TOUGH CALL ON FRIDAY AS TEMPS MAY STILL BE WARM 
ENOUGH FOR A RAIN/SNOW MIX DURG FRIDAY WITH PRECIP CHANGING TO SNOW 
SHOWERS FRIDAY NIGHT.  SATURDAY, WITH NW FLOW BEHIND THE LOW EXPECT 
CHC RAIN/SNOW SHWRS WITH HIGHS GENLY UPPER 30S TO ARND 40.
WILL CONTINUE CHC SNOW SHWRS SAT NGT SE OF LKS ERIE AND ONTARIO AS 
COLD NW FLOW CONTINUES WITH ONLY SLGT CHC POPS OUTSIDE OF THESE 
AREAS. ON SUNDAY HIGH PRESSURE WILL SPREAD INTO THE REGION WITH 
DRIER AIR.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
DURING THE REST OF TONIGHT...RIDGING IS EXPECTED TO REMAIN INTACT
OVER THE AREA WITH GENERALLY CLEAR SKIES CONTINUING. WITH ONLY A
WEAK GRADIENT IN PLACE AND SFC T-TD SPREADS EXPECTED TO GET
RELATIVELY NARROW...WOULD NOT BE SURPRISED TO SEE SOME PATCHY
MVFR FOG FORM JUST ABOUT ANYWHERE OVERNIGHT...AND HAVE THEREFORE
CONTINUED THE MENTION OF THIS IN THE FORECAST.

ANY PATCHY FOG THAT DEVELOPS OVERNIGHT SHOULD THEN QUICKLY DISSIPATE
WITH SUNRISE AND THE RETURN OF DIURNAL HEATING ON MONDAY...LEAVING
BEHIND VFR CONDITIONS FOR THE BALANCE OF THE DAY WITH ONLY AN
INCREASE IN CIRRUS EXPECTED DURING THE AFTERNOON. 

DURING MONDAY EVENING...THE CIRRUS WILL GRADUALLY THICKEN AND
LOWER INTO A MID LEVEL CLOUD DECK FROM SOUTH TO NORTH. AT THE SAME
TIME...THERE WILL ALSO BE AN INCREASE IN LOW LEVEL
MOISTURE/CLOUDINESS...THOUGH GENERAL VFR CONDITIONS ARE STILL
EXPECTED TO CONTINUE THROUGH THE END OF THE TAF PERIOD.

OUTLOOK...
TUESDAY...MAINLY VFR. 
WEDNESDAY AND THURSDAY...VFR/MVFR WITH A CHANCE OF RAIN SHOWERS.
FRIDAY...MVFR WITH A CHANCE OF RAIN/SNOW SHOWERS.

&&

.MARINE...
WINDS AND WAVES ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVSRY 
RANGE THROUGH TUESDAY. THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE 
OVER NEW BRUNSWICK AND LOW PRESSURE ALONG THE MID ATLANTIC COAST 
WILL RESULT IN AN INCREASE IN EASTERLY WINDS ON THE WESTERN PORTION 
OF LAKE ONTARIO MONDAY AFTERNOON AND EVENING. IT WILL PRODUCE CHOPPY 
CONDITIONS ON THE WESTERN HALF OF LAKE ONTARIO...BUT CONDITIONS ARE 
EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA.

&&

.CLIMATE...
STILL NO MEASURABLE SNOW SO FAR THIS SEASON OVER MOST OF WESTERN NY. 
WE ARE ALREADY TWO WEEKS LATE (NORMAL DATES ARE NOV 7 BUF AND NOV 8 
ROC). WE WILL AT LEAST GET TO FRIDAY (27TH) AND IF SO...WILL BE 
LATEST IN 61 YRS (1948) AT BUF...AND LATEST IN 46 YRS (1963) AT ROC. 
THE ALL TIME RECORD LATEST DATES FOR FIRST MEAS SNOW ARE DEC 3 1899 
AT BUF AND DEC 10 1948 AT ROC. WE WILL NOT LIKELY REACH THOSE DATES 
AS WX PATTERN LOOKS COLDER WITH SOME SNOW THREAT BEGINNING LATER 
FRIDAY. STAY TUNED.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...JJP
NEAR TERM...JJR/SFM
SHORT TERM...JJP
LONG TERM...JJP
AVIATION...JJR/SFM
MARINE...JJP
CLIMATE...SFM