Area Forecast Discussion
Issued by NWS Buffalo, NY

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KBUF 171753
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
153 PM EDT FRI APR 17 2015

.SYNOPSIS...
THE DISTURBANCE THAT PRODUCED SHOWERS ACROSS THE REGION OVERNIGHT
WILL GIVE WAY TO A WEAK AREA OF HIGH PRESSURE THIS AFTERNOON AND
EVENING. THIS WILL EVENTUALLY LEAD TO IMPROVING CONDITIONS DURING
THE COURSE OF TODAY WITH FAIR WEATHER TONIGHT. WHILE A ROBUST UPPER
LEVEL DISTURBANCE WILL GENERATE SOME CLOUDS AND SPOTTY SHOWERS OVER
THE NORTH COUNTRY ON SATURDAY...THE WEEKEND SHOULD BE A NICE ONE AS
CANADIAN HIGH PRESSURE WILL BUILD ACROSS OUR REGION TO SUPPORT
GENEROUS AMOUNTS OF SUN ALONG WITH SEASONABLY MILD TEMPERATURES.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE MID LEVEL CIRCULATION THAT PRODUCED WIDESPREAD SHOWERS ACROSS
THE REGION LAST NIGHT IS IN THE PROCESS OF EXITING ACROSS NEW
ENGLAND. LOW CLOUDS HAVE BEEN STUBBORN TO CLEAR BEHIND THIS FEATURE
WITH PLENTY OF LOW LEVEL MOISTURE AIDED BY ADVECTION PROCESSES
ACROSS THE COLD LAKES. EXPECT CLEARING TO BECOME MORE RAPID BY LATE
AFTERNOON AS A DRIER PUSH OF AIR ACROSS SOUTHERN ONTARIO MAKES
HEADWAY.

DEWPOINTS IN THE UPPER 40S TO LOWER 50S CROSSING THE LAKES WILL
CONTINUE TO PRODUCE AREAS OF FOG EAST OF LAKES ERIE AND ONTARIO
THROUGH MID TO LATE AFTERNOON.

TEMPERATURES TODAY WILL GENERALLY CLIMB INTO THE UPPER 50S TO LOW
60S DURING THE MID AND LATE AFTERNOON AS THE LOWER CLOUDS CLEAR
OUT...WITH SOME MID 60S NOT OUT OF THE QUESTION IN THE NORMALLY
WARMER SOUTHERN TIER AND GENESEE VALLEYS. COOL SPOTS WILL INCLUDE
THE TUG HILL...AND SITES NORTHEAST OF LK ERIE (IE THE BUF METRO
AREA) WHERE A COOLING SOUTHWEST WIND WILL BE IN PLACE.

TONIGHT...THE AFOREMENTIONED WEAK SFC HIGH WILL BE OUR MAIN WEATHER
FEATURE SO SKIES WILL BE CLEAR TO PARTLY CLOUDY AND WINDS WILL BE
LIGHT. THIS WILL SET THE STAGE FOR A CHILLY NIGHT...AS MARGINALLY
FAVORABLE RADIATIONAL COOLING SHOULD ALLOW TEMPS TO SETTLE INTO THE
UPPER 30S TO LOWER 40S FOR MOST LOCATIONS. THESE READINGS WILL
ACTUALLY BE VERY CLOSE TO SEASONAL NORMALS.

THE ONLY FLY IN THE OINTMENT WILL BE A MOISTURE STARVED COLD FRONT
THAT WILL CROSS THE FORECAST AREA TOWARDS DAYBREAK. THIS FEATURE IS
ONLY EXPECTED TO PRODUCE A SCT-BKN STRATO-CU CLOUD DECK...ALTHOUGH
MORE EXTENSIVE CLOUD COVER WILL BE POSSIBLE ACROSS THE THOUSAND
ISLANDS REGION IN THE VCNTY OF A ROBUST MID LEVEL SHORTWAVE.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY NIGHT/...
ON SATURDAY...A RATHER POTENT SHORTWAVE TROUGH WILL QUICKLY DROP
SOUTHEASTWARD ACROSS NORTHERN NEW YORK AND NEW ENGLAND...ALONG WITH
ITS CORRESPONDING WEAK SURFACE REFLECTION. WHILE THE DEEPEST
MOISTURE AND BEST LARGE-SCALE ASCENT ASSOCIATED WITH THIS WAVE WILL
REMAIN TO OUR NORTHEAST...THERE MAY STILL BE JUST ENOUGH OF BOTH TO
GENERATE SOME CLOUDS AND SCATTERED LIGHT SHOWERS ACROSS THE SAINT
LAWRENCE VALLEY AND ADJOINING PORTIONS OF THE NORTH COUNTRY THROUGH
EARLY SATURDAY AFTERNOON...FOR WHICH SOME CHANCE POPS HAVE BEEN
ADDED TO THE FORECAST.

AFTER THAT TIME...ANTICYCLONIC VORTICITY ADVECTION AND STRONG
DRYING/SUBSIDENCE IN THE WAKE OF THE WAVE SHOULD LEAD TO A RETURN
TO DRY WEATHER AND INCREASING SUNSHINE THROUGH THE REMAINDER OF
THE AFTERNOON. MEANWHILE FURTHER TO THE SOUTH AND WEST...THE WEAK
AND MOISTURE-STARVED SURFACE COLD FRONT ASSOCIATED WITH THIS
SYSTEM WILL STRUGGLE TO PRODUCE MUCH MORE THAN A BRIEF INCREASE IN
CLOUDS...WITH SURFACE-BASED HIGH PRESSURE AND DRY WEATHER
OTHERWISE REMAINING DOMINANT THROUGH THE DAY. AS FOR
TEMPERATURES...COOLING ALOFT ASSOCIATED WITH THE PASSING WAVE WILL
LEAD TO A MODEST SOUTHWEST- TO-NORTHEAST GRADIENT IN 850 MB
TEMPS...WHICH WILL BE REFLECTED AT THE SURFACE BY HIGHS GENERALLY
RANGING FROM THE MID AND UPPER 60S SOUTH OF LAKE ONTARIO...TO
WITHIN A FEW DEGREES OF 60 ACROSS THE NORTH COUNTRY. THIS
STATED...A DEVELOPING NORTHWESTERLY LOW LEVEL FLOW BEHIND THE
FRONT WILL KEEP TEMPS CONFINED TO THE LOWER TO MID 50S ALONG THE
SOUTH SHORES OF BOTH LAKES.

SATURDAY NIGHT AND SUNDAY...EXPANSIVE CANADIAN HIGH PRESSURE DRAPED
FROM JAMES BAY TO THE CENTRAL GREAT LAKES WILL SLOWLY DRIFT EASTWARD
INTO QUEBEC AND NEW ENGLAND...WHILE A DEEPENING UPPER LEVEL TROUGH
DEVELOPS ACROSS THE EASTERN PLAINS STATES AND WESTERN GREAT LAKES...
AND A CORRESPONDING COMPLEX SURFACE WAVE SLOWLY CONSOLIDATES ALONG
ITS EASTERN FLANK. THE LARGE SURFACE RIDGE WILL KEEP DRY WEATHER AND
MAINLY CLEAR/MOSTLY SUNNY SKIES INTACT ACROSS OUR AREA THROUGH AT
LEAST MIDDAY ON SUNDAY...BEFORE INCREASING WARM ADVECTION ALOFT
LEADS TO INCREASING MID AND HIGH CLOUDS AND PERHAPS THE OUTSIDE
CHANCE OF A SHOWER ACROSS FAR SOUTHWESTERN NEW YORK BY LATE SUNDAY
AFTERNOON.

TEMPERATURE-WISE...THE SURFACE RIDGE WILL PRODUCE NEAR
IDEAL CONDITIONS FOR RADIATIONAL COOLING AS IT CRESTS ACROSS OUR
REGION SATURDAY NIGHT...WHICH SHOULD RESULT IN OVERNIGHT LOWS IN
THE LOWER TO MID 30S. FOLLOWING THIS...THE COMBINATION OF
PLENTIFUL SUNSHINE AND SOME MODEST WARMING ALOFT SHOULD ALLOW
READINGS TO REBOUND RATHER NICELY ON SUNDAY...WHEN MOST AREAS
SHOULD EXPERIENCE HIGHS IN THE LOWER TO MID 60S. THE EXCEPTION TO
THIS WILL BE ALONG THE SOUTH SHORE OF LAKE ONTARIO...WHERE A
STRENGTHENING EAST-NORTHEASTERLY FLOW WILL AGAIN KEEP HIGHS
CONFINED TO THE LOWER TO MID 50S.

AFTER THAT...CONDITIONS WILL DETERIORATE FOR THE REMAINDER OF THE
PERIOD AS THE AFOREMENTIONED UPPER LEVEL TROUGH DEEPENS AND DIGS
FURTHER SOUTHEASTWARD ACROSS THE GREAT LAKES...AND ITS ATTENDANT
SURFACE REFLECTION LIFTS FROM WISCONSIN/LAKE MICHIGAN INTO CENTRAL
ONTARIO PROVINCE. IN THE PROCESS...THIS LATTER FEATURE WILL SLOWLY
PUSH ITS ASSOCIATED WARM FRONT ACROSS THE REGION SUNDAY NIGHT AND
MONDAY MORNING...FOLLOWED BY ITS TRAILING COLD FRONT LATER MONDAY
AFTERNOON AND MONDAY NIGHT.

EXPECT A HIGH LIKELIHOOD OF SHOWERS TO ACCOMPANY THE PASSAGE OF BOTH
FRONTAL BOUNDARIES...WITH THE SHOWERS ALONG THE WARM FRONTAL ZONE
RECEIVING AN ADDED BOOST FROM INCREASING LOW LEVEL CONVERGENCE AT
THE NOSE OF A DEVELOPING 50-60 KT SOUTHERLY LOW LEVEL JET AND ITS
ATTENDANT ENHANCEMENT OF THE OVERALL WARM AIR ADVECTION REGIME. IN
BETWEEN THE TWO BOUNDARIES...A SHORT PERIOD OF RELATIVELY DRIER
WEATHER MAY OCCUR WITHIN THE WARM SECTOR ON MONDAY...AND HAVE
ATTEMPTED TO REFLECT THIS IN THE GRIDS WITH A 3-6 HOUR PERIOD OF
LOWER (CHANCE) POPS SLIDING EASTWARD ACROSS THE FORECAST AREA.
FOLLOWING THE PASSAGE OF THE COLD FRONT...SHOWER CHANCES SHOULD TEND
TO DIMINISH AT LEAST SOMEWHAT FROM WEST TO EAST MONDAY NIGHT...
THOUGH THESE WILL LIKELY NOT END ALTOGETHER AS ADDITIONAL SHORTWAVE
ENERGY ATTENDANT TO THE UPPER TROUGH ROTATES THROUGH THE REGION
ALOFT.

ONE THING WE`LL NEED TO KEEP AN EYE ON FOR SUNDAY NIGHT WILL BE THE
POTENTIAL FOR A BRIEF PERIOD OF STRONGER SOUTH-SOUTHEASTERLY
DOWNSLOPE WINDS ALONG THE LAKE ERIE SHORELINE AS THE AFOREMENTIONED
LOW LEVEL JET PASSES ACROSS THE AREA. BOTH THE 00Z NAM AND GFS HINT
AT THIS POTENTIAL BY BRIEFLY DEVELOPING A REGION OF 25-30 KT
SUSTAINED SURFACE WINDS ALONG THE LAKE ERIE SHORELINE...WHICH IN
CONJUNCTION WITH 50-60 KT WINDS AT 925 MB WOULD TYPICALLY BE WORTH
AT LEAST A WIND ADVISORY WERE THIS TO ACTUALLY BE REALIZED. FOR THE
TIME BEING...WE WILL ADD A MENTION OF THIS POSSIBILITY TO THE HWO...
AND WILL CONTINUE TO EVALUATE THIS POTENTIAL OVER THE NEXT DAY OR
TWO.

WITH RESPECT TO TEMPERATURES...READINGS WILL CONTINUE TO AVERAGE
ABOVE NORMAL THROUGH THE LAST 36 HOURS OF THE PERIOD...WITH LOWS
PRIMARILY RANGING THROUGH THE 40S SUNDAY NIGHT...HIGHS REACHING
THE UPPER 50S TO MID 60S ON MONDAY...AND LOWS MONDAY NIGHT FALLING
BACK TO THE LOWER TO MID 40S.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
IN THE EXTENDED PORTION OF THE FORECAST...IT CONTINUES TO APPEAR
THAT A LARGE CLOSED LOW WILL MEANDER OVER ONTARIO AND THE NORTHERN
GREAT LAKES FOR MUCH OF NEXT WEEK. THE 00Z MEDIUM RANGE GUIDANCE
SUITE CONTINUES TO SUGGEST THE POTENTIAL FOR PERIODIC CHANCES OF
SHOWERS WITH THESE PRIMARILY TIED TO THE HEIGHT OF THE DIURNAL
HEATING CYCLE EACH DAY...THOUGH WOULD NOT BE SURPRISED IF THE BULK
OF THE PERIOD REMAINED DRY GIVEN THE NORTHWARD DISPLACEMENT OF
NEGATIVE HEIGHT ANOMALY. WHAT APPEARS MUCH MORE CERTAIN IS THAT THIS
PATTERN WILL RESULT IN A RETURN TO BELOW NORMAL TEMPERATURES...WITH
DAYTIME HIGHS FALLING BACK TO THE UPPER 40S AND LOWER 50S BY
MIDWEEK.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
EXTENSIVE LOW STRATUS ACROSS MUCH OF THE REGION WILL THIN FROM
NORTHWEST TO SOUTHEAST THIS AFTERNOON. IFR AND MVFR CIGS WILL
IMPROVE TO VFR BY LATE AFTERNOON OR EARLY EVENING ACROSS THE BULK OF
THE AREA. MOIST LOW LEVELS OVER THE COLD LAKES WILL CONTINUE TO
PRODUCE AREAS OF FOG OVER AND EAST OF LAKES ERIE AND ONTARIO THROUGH
LATE AFTERNOON WITH LOCAL IFR VSBY.

TONIGHT SKIES WILL FINISH CLEARING WITH VFR PREVAILING. ON SATURDAY
A MOISTURE STARVED SHARP MID LEVEL DISTURBANCE AND COLD FRONT WILL
CROSS THE REGION. THE STRONGEST ASCENT WILL CROSS THE NORTH COUNTRY
WITH INCREASING CLOUDS AND POSSIBLY A FEW LIGHT SHOWERS FROM MID
MORNING THROUGH MID AFTERNOON. CIGS AND VSBY WILL REMAIN VFR WITH
THIS GIVEN THE DRY LOW LEVELS. FOR THE REST OF THE AREA JUST EXPECT
A SHIFT IN WIND DIRECTION AND INCREASE IN SPEED WITH THE FRONTAL
PASSAGE AND JUST A FEW SCATTERED CLOUDS.

OUTLOOK...
SUNDAY...VFR.
SUNDAY NIGHT AND MONDAY...AREAS OF MVFR WITH OCCASIONAL SHOWERS AND
GUSTY WINDS.
TUESDAY AND WEDNESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.

&&

.MARINE...
FLAG FREE CONDITIONS ARE EXPECTED ACROSS THE LOWER GREAT LAKES
THROUGH THE WEEKEND.

WEAK HIGH PRESSURE WILL BUILD ACROSS THE REGION TODAY AND TONIGHT
AND THIS WILL KEEP RELATIVELY LIGHT WINDS AND NEGLIGIBLE WAVES IN
PLACE ON BOTH LAKES ONTARIO AND THE ICE FREE SECTIONS OF LK ERIE.
A MOIST FLOW ACROSS THE COLD LAKES WILL CONTINUE TO PRODUCE AREAS
OF FOG ON BOTH LAKES THROUGH MID AFTERNOON.

A STRONGER CANADIAN SFC HIGH WILL NOSE SOUTH ACROSS THE LOWER GREAT
LAKES ON SATURDAY. WHILE THIS WILL PROMOTE FRESHENING WEST TO
NORTHWEST WINDS ON LAKE ONTARIO...CONDITIONS SHOULD REMAIN BELOW
SMALL CRAFT ADVISORY CRITERIA. THE SFC HIGH WILL THEN MOVE EAST OF
THE REGION DURING THE SECOND HALF OF THE WEEKEND WITH WINDS VEERING
TO THE EAST FOR SUNDAY. THIS WILL LIKELY LEAD TO CHOPPY CONDITIONS
FOR NEARSHORE AREAS WEST OF HAMLIN BEACH.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 8 PM EDT SATURDAY FOR SLZ022-
         024.

&&

$$

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




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.