000
FXUS61 KBUF 191459
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1059 AM EDT SUN MAY 19 2013

.SYNOPSIS...
HIGH PRESSURE CENTERED JUST OFF THE NEW ENGLAND COAST WILL CONTINUE 
TO DRIFT SLOWLY EASTWARD TODAY...WHILE CONTINUING TO PUMP WARMER AIR 
INTO THE AREA. ASIDE FROM A FEW LIGHT SHOWERS ACROSS THE NORTH 
COUNTRY TODAY...CONDITIONS SHOULD REMAIN MAINLY DRY THROUGH 
TONIGHT...BEFORE A FRONTAL BOUNDARY STALLS OUT OVER THE REGION FOR 
MUCH OF THE WORK WEEK AND ACTS AS THE FOCUS FOR PERIODS OF SHOWERS 
AND THUNDERSTORMS.

&&

.NEAR TERM /THROUGH TONIGHT/...
CURRENT RADAR TREND SHOWS THE LIGHT SHOWER AND SPRINKLES OVER THE 
NORTH COUNTRY CONTINUING TO WEAKEN AS THE WEAK SHORT WAVE 
RESPONSIBLE FOR THIS ACTIVITY SLOWLY LIFTS AWAY FROM THE REGION LATE 
THIS MORNING. BEHIND THIS WEAK DISTURBANCE VISIBLE SATELLITE SHOWS 
CLOUD COVER BEGINNING TO QUICKLY ERODE OVER KBUF/KIAG/KJHW AND NOW 
INTO KROC. ELSEWHERE...SHORT TERM GUIDANCE SUGGEST VARYING AMOUNTS OF 
MID AND HIGH LEVEL CLOUDS WILL PERSIST AS MID LEVEL MOISTURE AND 
WARM AIR ADVECTION HELPS TO KEEP TEMPERATURES A LITTLE BIT COOLER 
ACROSS NORTH CENTRAL NY. 

THIS EVENING...EXPECT MAINLY DRY CONDITIONS TO CONTINUE TO PREVAIL 
AS THE BEST SWATH OF WARM ADVECTION/ASSOCIATED MOISTURE SHIFTS 
EASTWARD AND OUT OF THE AREA...WHICH SHOULD LEAD TO A CORRESPONDING 
DECREASE IN MID AND HIGH CLOUD COVER THROUGH THE EARLY OVERNIGHT 
HOURS. LATER ON IN THE NIGHT...CLOUD COVER WILL BEGIN TO INCREASE 
AGAIN FROM THE NORTH AS A WEAK FRONTAL BOUNDARY OVER ONTARIO 
PROVINCE BEGINS TO SAG SOUTHWARD TOWARD OUR REGION...HOWEVER EXPECT 
ANY SHOWER CHANCES ASSOCIATED WITH THIS TO REMAIN IN THE SLIGHT 
CHANCE RANGE GIVEN BOTH ITS SLOW APPROACH AND THE UNFAVORABLE TIME 
OF DAY...AND MAINLY CONFINED TO THE NORTH COUNTRY AT THAT. 

WITH RESPECT TO TEMPERATURES...850 MB TEMPS WILL CLIMB TO BETWEEN 
+10C AND +13C TODAY...WITH THE WARMEST AIR FOUND ACROSS FAR WESTERN 
NEW YORK. COUPLED WITH A SOUTHERLY DOWNSLOPE FLOW...THIS SHOULD BE 
ENOUGH TO BOOST HIGHS BACK INTO THE MID TO UPPER 70S ACROSS THE BULK 
OF THE CWA TODAY...SAVE FOR TWO AREAS. THE FIRST OF THESE WILL BE 
ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER AND NORTH COUNTRY 
WHERE TEMPS SHOULD REMAIN CONFINED TO THE LOWER 70S...AND THE SECOND 
WILL BE ALONG THE IMMEDIATE LAKE ONTARIO SHORE FROM ROCHESTER OVER 
TO THE NIAGARA RIVER WHERE AN EAST-NORTHEASTERLY ONSHORE FLOW WILL 
HELP KEEP HIGHS CONFINED TO THE 60S. WITH A CONTINUED SOUTHERLY FLOW 
AND SURFACE DEWPOINTS REMAINING IN THE MID-UPPER 50S...RATHER MILD 
OVERNIGHT LOWS WILL THEN FOLLOW FOR TONIGHT...WITH READINGS RANGING 
FROM THE MID-UPPER 50S IN INTERIOR PORTIONS OF THE SOUTHERN TIER AND 
NORTH COUNTRY TO THE LOWER 60S ACROSS THE LAKE PLAINS.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
AN ANOMALOUSLY DEEP AND EXPANSIVE UPPER LEVEL LOW OVER THE NORTHERN 
PLAINS AT THE BEGINNING OF THE WEEK WILL KEEP A DOWNSTREAM RIDGE IN 
PLACE OVER THE LOWER GREAT LAKES INTO WEDNESDAY. THIS WILL GUARANTEE 
ABOVE NORMAL TEMPERATURES FOR THIS SHORT TERM PERIOD...BUT THE FLIP 
SIDE TO THIS COIN IS THAT WE WILL LIKELY EXPERIENCE FAIRLY UNSETTLED 
WEATHER AS WELL. THE TIMING OF SHOWERS AND THUNDERSTORMS WILL 
CERTAINLY BE A CHALLENGE THOUGH...AS MANY OF THESE WILL EITHER BE 
DIURNALLY DRIVEN OR TIED TO IMPULSES WITHIN THE UPPER LEVEL FLOW. 
THE DETAILS...

WHILE A FAIRLY STRONG RIDGE WILL BE IN PLACE OVER THE UPPER OHIO 
VALLEY AND LOWER GREAT LAKES ON MONDAY...HIGH PRESSURE OVER JAMES 
BAY WILL PUSH A WEAK FRONTAL BOUNDARY SOUTH ACROSS LAKE ONTARIO. 
THIS FRONT WILL ENCOUNTER A SUMMER LIKE AIRMASS AS DEW POINTS ARE 
EXPECTED TO CLIMB INTO THE LOWER 60S WHILE H85 TEMPS IN THE VCNTY OF 
15C WILL ENCOURAGE NR SFC TEMPS TO CLIMB INTO THE LOW 80S (MID 80S 
IN SOME VALLEYS). THIS COMBINATION WILL LEAD TO CAPES OF 1000-2000 
J/KG...WITH THE MOST UNSTABLE AIR EXPECTED OVER THE FINGER LAKES AND 
SRN TIER. 

KEEPING THIS IN MIND...THE GENERAL SYNOPTIC SUBSIDENCE FROM THE 
AFOREMENTIONED RIDGE SHOULD HELP TO SUPPRESS ANY CONVECTION FOR A 
LARGE PORTION OF THE DAY. A FAIR AMOUNT OF HEATING THROUGH THE 
MIDDAY HOURS MAY BE ABLE TO OVERCOME THIS THOUGH...ESPECIALLY GIVEN 
THE PRESENCE OF THE WEAK FRONTAL BOUNDARY AND FAVORABLE LOW LEVEL 
THERMODYNAMICS. A LITTLE HIGHER UP...AM NOT IMPRESSED WITH THE 
FORECAST MID LEVEL LAPSE RATES AND THE NAM BUFKIT PROFILES ARE 
SUGGESTING A WEAK CAP ARND 10K FT. WHILE THESE ARE NOT CONDUCIVE FOR 
WIDESPREAD CONVECTION...IF SBCAPES OF 1000-2000 J/KG CAN BE REALIZED 
THEN THIS SHOULD NOT POSE TOO MUCH OF A PROBLEM FOR SCATTERED STORMS 
TO DEVELOP DURING THE COURSE OF THE AFTERNOON. A CLOSER LOOK AT THE 
UNDERLYING AIRMASS SUGGESTS THAT A VERY WEAK WIND FIELD WILL BE IN 
PLACE THROUGH 10K FT...AND WITH PWAT VALUES IN THE VCNTY OF 1.25"... 
THAT SHOULD HEIGHTEN THE CHANCE FOR SLOW MOVING DOWNPOURS WITHIN ANY 
CONVECTION THAT DOES DEVELOP. OTHERWISE...MONDAY WILL BE SUMMERY 
WITH MAINLY DRY CONDITIONS FOR THE BULK OF THE DAY.

THE WEAK FRONTAL BOUNDARY WILL SLOWLY SETTLE SOUTH OF THE REGION 
MONDAY NIGHT. WHILE THE THREAT FOR THUNDERSTORMS WILL GENERALLY 
CEASE WITH THE REMOVAL OF DIURNAL HEATING...IMPULSES DROPPING DOWN 
THE FRONT SIDE OF THE H5 RIDGE (ALONG AND NORTH OF SFC FRONT) WILL 
KEEP THE CHANCE FOR SHOWERS IN PLACE. IT MAY ALSO BE UNCOMFORTABLY 
HUMID FOR PARTS OF THE FORECAST AREA...PENDING THE PROGRESSION OF 
THE SFC FRONTAL BOUNDARY. THE SOUTHERN TIER STANDS THE HIGHEST 
CHANCE FOR EXPERIENCING A SUMMERY NIGHT.

THE PRESENCE OF THE NEARLY STALLED FRONTAL BOUNDARY IN THE VCNTY OF 
OUR FORECAST AREA WILL KEEP UNSETTLED CONDITIONS IN PLACE FOR 
TUESDAY AND TUESDAY NIGHT. CONFIDENCE IN THE TIMING AND EXTENT OF 
THIS PCPN WILL BE LOW AS THE MAINSTREAM GUIDANCE DIFFERS ON THE 
PLACEMENT OF THE FRONT. WE WILL LEAN MORE ON THE ECMWF SOLUTION... 
WHICH HANGS THE FRONT UP OVER OUR AREA. WILL THUS KEEP LIKELY POPS 
IN PLAY SOUTH OF LK ONTARIO FOR TUES/TUES NIGHT WHILE USING CHC POPS 
ACROSS THE NORTH COUNTRY.

THE BLOCKING UPPER LEVEL LOW THAT WAS FOUND OVER THE NORTHERN PLAINS 
AT THE START OF THIS PERIOD WILL FINALLY OPEN UP AND BECOME ABSORBED 
WITHIN A DIGGING LONGWAVE TROUGH OVER EASTERN CANADA. THIS WILL 
KNOCK DOWN WHATS LEFT OF ANY H5 RIDGING OVER THE LOWER GREAT LAKES 
AND ALLOW BROAD SFC LOW PRESSURE TO SETTLE OVER OUR REGION. THE 
RESULT WILL BE MORE SHOWERS AND THUNDERSTORMS. WILL USE HIGH CHC 
POPS FOR NOW GIVEN THE AMOUNT OF UNCERTAINTY WITHIN THE VARIOUS 
PACKAGES.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
IT WILL BE MUCH COOLER DURING THIS PERIOD...AS A LONGWAVE TROUGH 
OVER EASTERN CANADA WILL DIG SOUTH ACROSS NEW ENGLAND AND THE LOWER 
GREAT LAKES. TEMPERATURES WILL DROP BELOW NORMAL BY FRIDAY AND WILL 
FURTHER COOL AS WE HEAD INTO THE MEMORIAL DAY WEEKEND.

IN TERMS OF PCPN...THERE WILL BE ANOTHER CHANCE FOR SHOWERS AND 
THUNDERSTORMS THURSDAY AND THURSDAY NIGHT WHEN A SHORTWAVE FROM THE 
CENTRAL PLAINS WILL PASS TOWARDS OUR REGION. UPPER LEVEL HEIGHT 
FALLS AND LOW LEVEL CONVERGENCE AHEAD OF A COOL POOL OF AIR WILL 
BRING SHOWERS AND PERHAPS SOME THUNDERSTORMS. INSTABILITY WILL NOT 
BE AS GREAT THURSDAY...COMPARED TO TUESDAY AND WEDNESDAY.

THE ECMWF WILL PHASE THIS CENTRAL PLAINS LOW WITH A SHORTWAVE 
DROPPING SOUTHWARD FROM EASTERN CANADA. THIS PHASING WILL DEVELOP A 
TROUGH THAT WILL DRIVE A COLD FRONT ACROSS THE REGION THURSDAY 
NIGHT. BEHIND THE COLD FRONT HIGH PRESSURE AND MUCH DRIER AND COOLER 
AIR WILL FILTER ACROSS THE EASTERN GREAT LAKES. HIGH PRESSURE WILL 
THEN BUILD ACROSS THE LOWER GREAT LAKES FOR FRIDAY AND SATURDAY.

&&

.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
AS OF 14Z...A NARROW BROKEN BAND OF SPRINKLES/LIGHT SHOWERS
ACROSS THE NORTH COUNTRY CONTINUES TO LIFT NORTHEAST AWAY FROM THE
REGION THIS AFTERNOON. ALL OF THIS IS ASSOCIATED WITH AN AREA OF ENHANCED
MID LEVEL MOISTURE AND ASSOCIATED WARM AIR ADVECTION. OTHERWISE...EXPECT
DRY WEATHER TO CONTINUE ACROSS THE REMAINDER OF THE REGION WITH
MOST AREAS JUST SEEING VARYING AMOUNTS OF MID AND HIGH CLOUD COVER
WITH VFR CONDITIONS PREVAILING. THE ONE EXCEPTION TO THIS WILL BE
ACROSS THE SOUTHERN TIER...WHERE AN AREA OF IFR/MVFR STRATUS WILL
LIKELY PERSIST UNTIL DIURNAL HEATING/MIXING HELPS TO ERODE THIS
LATER ON THIS MORNING.

THIS AFTERNOON...THE COMBINATION OF DEEPER MOISTURE AND WEAK WARM 
AIR ADVECTION COULD TOUCH OFF A FEW ADDITIONAL SCATTERED SHOWERS 
EAST OF LAKE ONTARIO...HOWEVER THESE SHOULD REMAIN LIGHT ENOUGH TO 
KEEP CIGS/VSBYS VFR. FARTHER WEST...EXPECT DRY VFR WEATHER TO 
PREVAIL UNDER CONTINUED MID AND HIGH CLOUD COVER. 

TONIGHT...VFR CONDITIONS WILL CONTINUE WITH MID AND HIGH CLOUDS 
THINNING OUT FROM WEST TO EAST THIS EVENING...BEFORE INCREASING 
AGAIN FROM THE NORTH LATE AS A WEAK FRONTAL BOUNDARY OVER ONTARIO 
PROVINCE BEGINS SAGGING SOUTHWARD.

OUTLOOK...  
MONDAY...MAINLY VFR...WITH A CHANCE OF MVFR IN SCATTERED AFTERNOON 
SHOWERS/THUNDERSTORMS.
TUESDAY AND THURSDAY...SCATTERED TO NUMEROUS SHOWERS AND 
THUNDERSTORMS WITH ASSOCIATED MVFR/IFR...OTHERWISE VFR.

&&

.MARINE...
QUIET CONDITIONS WILL REMAIN IN PLACE ACROSS THE LOWER LAKES THROUGH 
TONIGHT...WITH RELATIVELY LIGHT TO MODEST SOUTHEASTERLY TO SOUTHERLY 
WINDS AND MINIMAL WAVES. AFTER THAT...GENERALLY LIGHT WINDS WILL 
CONTINUE THROUGH MUCH OF NEXT WEEK...ALBEIT WITH AN INCREASING RISK 
OF SHOWERS AND THUNDERSTORMS AS A FRONTAL BOUNDARY TAKES UP 
RESIDENCE ACROSS THE LOWER LAKES REGION.

&&

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

&&

$$

SYNOPSIS...JJR
NEAR TERM...AR/HITCHCOCK/JJR
SHORT TERM...RSH
LONG TERM...RSH/THOMAS
AVIATION...JJR
MARINE...JJR