Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 261119
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
719 AM EDT TUE MAY 26 2015

.SYNOPSIS...
PERSISTENT HIGH PRESSURE ANCHORED OFF THE EAST COAST WILL KEEP
MID SUMMERLIKE WARMTH ACROSS WESTERN AND NORTH CENTRAL NEW YORK...
WHILE INCREASING HUMIDITY AND SEVERAL DISTURBANCES WILL PROVIDE
INCREASING CHANCES OF SOME MUCH NEEDED RAINFALL THROUGH MID WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
ASIDE FROM A FEW LIGHT SHOWERS ACROSS THE WESTERN SOUTHERN
TIER... LARGELY DRY AND QUIET WEATHER SHOULD BE THE GENERAL RULE
THROUGH THE MID TO LATE MORNING HOURS. AFTER THAT TIME...THE
COMBINATION OF INCREASING DIURNAL INSTABILITY AND THE APPROACH OF
YET ANOTHER MID LEVEL SHORTWAVE AND ATTENDANT MOISTURE FROM THE
OHIO VALLEY WILL LEAD TO AN INCREASING POTENTIAL FOR CONVECTION
THROUGH THE AFTERNOON HOURS. AT THIS POINT IT STILL APPEARS AS IF
THE CONVECTION WILL BE MOST LIKELY TO INITIATE ALONG A DEVELOPING
LAKE BREEZE BOUNDARY TO THE LEE OF LAKE ERIE AS WELL AS IN AREAS
OF FAVORABLE OROGRAPHIC INFLUENCES...BEFORE SPREADING
NORTHEASTWARD INTO THE GENESEE VALLEY AND FINGER LAKES AS
ADDITIONAL LIFT FROM THE AFOREMENTIONED SHORTWAVE COMES INTO PLAY.
WITH CAPE VALUES LARGELY APPEARING MODEST... CAPE PROFILES
TALL/SKINNY IN NATURE...AND 0-6 KM BULK SHEAR VALUES GENERALLY
LESS THAN 30 KNOTS...ANY POTENTIAL FOR SEVERE STORMS STILL APPEARS
TO BE FAIRLY LIMITED.

AS WE GET INTO THIS EVENING...LINGERING DIURNALLY-DRIVEN
CONVECTION SHOULD CONTINUE TO LIFT NORTHEASTWARD WHILE WEAKENING
OWING TO THE LOSS OF HEATING AND THE DEPARTURE OF THE SUPPORTING
SHORTWAVE. THIS SHOULD LEAD TO A RELATIVE MINIMUM IN CONVECTION
FOR THE MIDDLE PART OF THE NIGHT...BEFORE AN APPROACHING MID LEVEL
TROUGH AND ATTENDANT LEAD SHORTWAVE/PRE-FRONTAL TROUGH BRINGS AN
INCREASING THREAT FOR SHOWERS AND STORMS BACK INTO FAR WESTERN NEW
YORK LATE.

WITH RESPECT TO TEMPERATURES...850 MB TEMPS OF +14C TO +15C
SHOULD TRANSLATE INTO WIDESPREAD SURFACE HIGHS IN THE UPPER 70S TO
MID 80S TODAY...WITH ANY REAL LAKE COOLING LIKELY CONFINED TO
AREAS IMMEDIATELY NORTHEAST OF THE LAKES. WITH AN EVEN MORE HUMID
AIRMASS AND A CONTINUED SOUTHERLY/SOUTHWESTERLY LOW LEVEL FLOW IN
PLACE... LOWS TONIGHT WILL LIKELY NOT FALL BELOW THE MID TO UPPER
60S.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
WHILE WE WILL LIKELY PICK UP SOME BADLY NEEDED RAINFALL ON
WEDNESDAY...THE BULK OF THE DAY COULD PROVE TO BE PCPN FREE. AS
WAS THE CASE IN THE PRECEDING 48 HOURS...STRONG RIDGING FOUND JUST
OFF THE EAST COAST WILL CONTINUE TO CIRCULATE WARM AND VERY HUMID
AIR NORTHWARD ACROSS THE LOWER GREAT LAKES...AS A WIDE OPEN GULF
WILL SUPPLY PWAT VALUES OF 1.75"...AT LEAST FOR THE FIRST HALF OF
THE DAY. THE RESULTING UNSTABLE AIRMASS WILL BE VERY SUPPORTIVE OF
CONVECTION...BUT THE DIFFICULT PART WILL BE TRYING TO TIME THE
VARIOUS SHORTWAVES AND BOUNDARIES THAT WILL TRIGGER SUCH.

A SHORTWAVE FOUND OVER THE OHIO VALLEY TUESDAY EVENING WILL PUSH
NORTHEAST AROUND THE PERIPHERY OF THE AFOREMENTIONED EAST COAST
RIDGE AND CROSS OUR FORECAST AREA DURING THE FIRST HALF OF
WEDNESDAY. THIS WILL LIKELY PRODUCE A ROUND OF SHOWERS AND
THUNDERSTORMS DURING THE MORNING HOURS. THE GOOD NEWS IS THAT THE
DIURNAL TIMING OF THIS CONVECTION WILL BE SUCH THAT INSTABILITY
WILL BE SOMEWHAT LIMITED (<500 J/KG)...THUS MINIMIZING THE RISK
FOR ANY SEVERE WEATHER. ON THE OTHER HAND THOUGH...THE MOISTURE
RICH AIRMASS WILL BE RIPE FOR HEAVY RAIN WITH SHORT MBE VECTORS
SUGGESTING THE POTENTIAL FOR SLOW MOVING DOWNPOURS. THE THREAT FOR
HEAVY RAIN WILL ALSO BE ENHANCED BY WARM CLOUD DEPTHS THAT ARE
FORECAST TO OVER 10K FT/3 KM DEEP...AND THE LOWER CAPE VALUES
QUOTED ABOVE. LOW TO MODERATE AMOUNTS OF CAPE ARE MORE FAVORABLE
FOR HEAVY RAIN BECAUSE WARM RAIN PROCESSES REQUIRE TIME TO CONVERT
CONDENSATE TO RAIN DROPS. HIGH CAPE ENVIRONMENTS TEND TO
ACCELERATE WATER VAPOR THROUGH THE WARM CLOUD LAYER...LIMITING
RAINFALL PRODUCTION.

IN ANY CASE...WEDNESDAY MORNING WILL LIKELY BE UNSETTLED ACROSS
WESTERN AND NORTH CENTRAL NEW YORK SO WILL INCREASE POPS TO LIKELY
FOR THE MORNING HOURS AND ALSO MENTION HEAVY RAIN. SUBSIDENCE AND
MARGINAL MID LEVEL DRYING IN THE WAKE OF THE SHORTWAVE SHOULD THEN
LEAD TO SOME CLEARING...AT LEAST OVER THE WESTERN COUNTIES DURING
THE AFTERNOON. WILL THUS BACK OFF ON THE AFTERNOON POPS FROM
CONTINUITY...ESPECIALLY OVER THE WESTERN COUNTIES. ANY CLEARING
WILL LEAD TO THE BUILD UP OF MORE INSTABILITY WHICH COULD `SET THE
TABLE` FOR ANOTHER ROUND OF CONVECTION WITH AN APPROACHING COOL
FRONT.

THIS COOL FRONT WILL CROSS OUR FORECAST AREA DURING THE FIRST
HALF OF WEDNESDAY NIGHT. WHILE THE DEEPEST PLUME OF MOISTURE WILL
BE WELL TO OUR EAST (OVR NEW ENGLAND)...PWAT VALUES IN EXCESS OF
AN INCH WILL BE IN PLACE ALONG WITH SBCAPES OF 500-1000 J/KG.
WHILE IT WOULD NOT BE OUT OF THE QUESTION THAT THESE STORMS COULD
PRODUCE STRONG WIND GUSTS...THE 0-3KM SHEAR VALUES ARE ONLY
FORECAST TO BE IN THE VCNTY OF 30 M/S AHEAD OF AND ALONG THE
FRONT...SO AM NOT OVERLY IMPRESSED AT THIS POINT. CONVECTION
ASSOCIATED WITH THIS FRONTAL PASSAGE WILL DIE DOWN AFTER MIDNIGHT.

ON THURSDAY...HIGH PRESSURE CENTERED NEAR JAMES BAY WILL NOSE
SOUTH ACROSS THE LOWER GREAT LAKES. THIS WILL BRING US A BRIEF
REPRIEVE FROM THE HUMID...UNSETTLED WEATHER AS DEW POINTS WILL
TEMPORARILY DROP BACK INTO THE 50S. THE DRIER AIRMASS SHOULD ALLOW
FOR A FAIR AMOUNT OF SUNSHINE...PARTICULARLY DURING THE AFTERNOON.
IT WILL ONLY BE MARGINALLY COOLER THOUGH WITH MANY AREAS STILL
CLIMBING INTO THE UPPER 70S.

AFTER WHAT SHOULD PROVE TO BE A FAIRLY COMFORTABLE NIGHT THURSDAY
NIGHT WHEN TEMPERATURES ARE EXPECTED TO DROP BACK TO BETWEEN 55
AND 60...IT WILL ONCE AGAIN BECOME WARM FOR FRIDAY. THE EAST COAST
RIDGE WILL AMPLIFY DURING THE DAY FRIDAY WITH A DEEPENING
SOUTHERLY FLOW BECOMING RE-ESTABLISHED OVER THE LOWER GREAT LAKES
IN ADVANCE OF THE NEXT COLD FRONTAL BOUNDARY. H85 TEMPS WILL CLIMB
BACK INTO THE MID TEENS C...WHICH WILL SUPPORT AFTERNOON MAX TEMPS
IN THE LOW TO MID 80S. THIS WARMING WILL COMBINE WITH AN
INCREASINGLY UNSTABLE AIRMASS AND ANY LAKE BREEZE BOUNDARY TO FUEL
POSSIBLE AFTERNOON AND EVENING THUNDERSTORMS ACROSS THE SOUTHERN
TIER. ELSEWHERE...PARTLY SUNNY WARM AND HUMID CONDITIONS SHOULD
PREVAIL.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
THINGS SHOULD BECOME MUCH MORE ACTIVE THOUGH AS WE MOVE INTO THE
WEEKEND. A POTENT UPPER LEVEL VORT MAX DROPPING OUT OF THE
CANADIAN ARCTIC WILL CARVE OUT A TROUGH ACROSS THE CANADIAN
PRAIRIE PROVINCES LATE THIS WEEK. THIS TROUGH IS FORECAST TO CROSS
NORTHERN ONTARIO AND MOVE INTO EASTERN QUEBEC SATURDAY. THOUGH
TIMING BETWEEN THE GLOBAL MODELS DIFFERS SLIGHTLY...THE GENERAL
CONSENSUS IS FOR THE THIS FEATURE TO PUSH A STRONG COLD FRONT
ACROSS THE FORECAST AREA LATE SATURDAY OR SATURDAY NIGHT. GIVEN
STRONG SYNOPTIC FORCING ASSOCIATED WITH THE FRONT...EXPECT SOME
SHOWERS/THUNDERSTORMS AS THE FRONT MOVES THROUGH. WHILE IT WILL
REMAIN QUITE WARM AND MUGGY AHEAD OF SATURDAY`S FRONT...
CONSIDERABLY COOLER AND DRIER WEATHER IS ANTICIPATED ON SUNDAY AS
THE COLD FRONT WILL SETTLE TO OUR SOUTH...YIELDING PLENTY OF
SUNSHINE AND HIGHS IN THE 60S.

WARMING WILL ONCE AGAIN OVERSPREAD THE LOWER GREAT LAKES ON
MONDAY AS THE RETURN FLOW AROUND HIGH PRESSURE OVER NEW ENGLAND
WILL ENCOURAGE H85 TEMPS TO CLIMB BACK TOWARDS +10C.

&&

.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
TODAY...MAINLY DRY/GENERAL VFR CONDITIONS SHOULD PERSIST INTO THE
MID TO LATE MORNING HOURS...BEFORE INCREASING DIURNAL INSTABILITY
AND THE APPROACH OF A MID LEVEL SHORTWAVE LEADS TO THE DEVELOPMENT
OF SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THIS AFTERNOON.
WHILE THESE SHOULD PRIMARILY BE FOCUSED FROM THE LEE OF LAKE ERIE
NORTHEASTWARD ACROSS THE GENESEE VALLEY AND FINGER LAKES...THESE
COULD BRING LOCALIZED REDUCTIONS TO MVFR AT JUST ABOUT ANY
LOCATION... SAVE FOR NORTHERN PORTIONS OF THE NORTH COUNTRY AND
SAINT LAWRENCE VALLEY.

AS WE GET INTO THIS EVENING...LINGERING DIURNALLY-DRIVEN
CONVECTION SHOULD CONTINUE TO LIFT NORTHEASTWARD WHILE WEAKENING
OWING TO THE LOSS OF HEATING AND THE DEPARTURE OF THE SUPPORTING
SHORTWAVE. THIS SHOULD LEAD TO A RELATIVE MINIMUM IN CONVECTION
FOR THE MIDDLE PART OF THE NIGHT...BEFORE AN APPROACHING MID LEVEL
TROUGH AND ATTENDANT LEAD SHORTWAVE/PRE-FRONTAL TROUGH BRINGS AN
INCREASING THREAT FOR SHOWERS AND STORMS BACK INTO FAR WESTERN NEW
YORK LATE. AT THIS POINT EXPECT THAT VFR CONDITIONS WILL CONTINUE
TO LARGELY PREVAIL.. THOUGH LOCAL REDUCTIONS TO MVFR WILL REMAIN
POSSIBLE WITHIN ANY CONVECTION.

OUTLOOK...
WEDNESDAY...VFR/MVFR WITH SHOWERS LIKELY ALONG WITH A CHANCE OF
THUNDERSTORMS.
WEDNESDAY NIGHT...MAINLY VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS/
ATTENDANT MVFR.
THURSDAY...MAINLY VFR WITH A LOW CHANCE OF EARLY MORNING SHOWERS
ACROSS THE NORTH COUNTRY.
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS
THE SOUTHERN TIER AND INTERIOR PORTIONS OF THE FINGER LAKES.
SATURDAY...MAINLY VFR WITH SCATTERED SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
HIGH PRESSURE ANCHORED OFF THE EAST COAST WILL KEEP A WEAK TO
MODEST PRESSURE GRADIENT INTACT ACROSS THE LOWER GREAT LAKES
THROUGH THE END OF THE WEEK. AS A RESULT...LIGHT TO MODEST WINDS
AND NEGLIGIBLE WAVES WILL CONTINUE TO BE THE GENERAL RULE...THOUGH
ANY THUNDERSTORMS COULD STILL PRODUCE LOCALLY HIGHER WINDS AND
WAVES THROUGH MIDWEEK.

&&

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

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH/WOOD
AVIATION...JJR
MARINE...JJR


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