Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 221952
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
352 PM EDT TUE APR 22 2014

.SYNOPSIS...
A COLD FRONT WILL SLIDE EAST OF THE REGION THIS EVENING USHERING IN
COLDER AIR AND BRINGING ANOTHER ROUND OF LIGHT RAIN SHOWERS WHICH
MAY MIX WITH SNOW IN SPOTS TONIGHT. TEMPERATURES WILL GRADUALLY WARM
TOWARD THE END OF THE WEEK AS HIGH PRESSURE BUILDS IN. A SLOW MOVING
AREA OF LOW PRESSURE WILL BRING A PERSISTENT CHANCE FOR SHOWERS AND
COOLER TEMPERATURES FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
A COLD FRONT WILL PUSH EAST OF THE REGION THROUGH THIS EVENING WHILE
BEHIND THIS A VORT MAX SPARKS SCATTERED SHOWERS. MEANWHILE...AREAS
OF FOG WILL LINGER NORTHEAST OF LAKE ONTARIO UNTIL WINDS SHIFT TO
THE NORTHWEST THIS EVENING. THE FORECAST CONTINUES TO PREFER THE
HRRR FOR NEAR-TERM GUIDANCE FOR TIMING THE FRONTAL PASSAGE.

A STRONGER VORT MAX WHICH IS EMBEDDED IN A BROADER UPPER LEVEL
TROF WILL DROP ACROSS THE REGION LATE THIS EVENING AND OVERNIGHT.
THIS WILL BRING ANOTHER ROUND OF STEADY SHOWERS...ESPECIALLY REGIONS
WHICH UPSLOPE IN A NORTHWEST FLOW. FOLLOWING A CONSENSUS OF HIGHER
RESOLUTION GUIDANCE WHICH IS BEST SUITED TO CAPTURE THESE MESOSCALE
FEATURES...THE STEADIEST SHOWERS SHOULD BE 06Z TO 12Z. FORECAST
TEMPERATURES PROFILES COOL TO SUPPORT THE POSSIBILITY OF
SNOW...ESPECIALLY ACROSS HIGHER TERRAIN. IT IS WORTH NOTING THAT THE
FORECAST SATURATED LAYER ONLY COOLS TO ABOUT -8C...BUT WITH THE VORT MAX
CROSSING SUSPECT THERE WILL PROBABLY BE ADEQUATE MOISTURE TO SUPPORT
DENDRITIC SNOW GROWTH DESPITE THE MARGINAL FORECAST HUMIDITY. IF
NOT...DRIZZLE OR FREEZING DRIZZLE WOULD BE A POSSIBILITY. FOR
NOW...EXPECT PRIMARILY LIGHT RAIN TO MIX WITH SNOW LATE TONIGHT.
WITH SURFACE TEMPERATURES FORECAST TO DROP INTO THE LOWER 30S...SOME
LIGHT ACCUMULATION OF AN INCH OR TWO IS POSSIBLE ACROSS HIGHER
TERRAIN.

THE UPPER LEVEL DISTURBANCE WILL SLOWLY EXIT INTO NEW ENGLAND ON
WEDNESDAY...BUT FAIRLY GUSTY NORTHWEST WINDS WILL REMAIN FOR MUCH OF
THE DAY. EXPECT SKIES TO CLEAR OUT FOR A BIT...BUT MAY FILL BACK IN
WITH DIURNAL CUMULUS BEFORE CLEARING OUT FOR GOOD LATE IN THE DAY.
ANY LINGERING RAIN OR SNOW SHOWERS SHOULD END BY NOON OR SO.
TEMPERATURES WILL BE ON THE COOL SIDE...WITH HIGHS IN THE UPPER 40S
TO AROUND 50.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
WEDNESDAY NIGHT A MID LEVEL TROUGH AND SURFACE LOW ALONG THE NEW
ENGLAND COAST WILL SHIFT FARTHER EAST AND OUT TO SEA OVERNIGHT. ANY
REMAINING CLOUDS ACROSS THE NORTH COUNTRY DURING THE EVENING WILL
CLEAR. OTHERWISE A NARROW SURFACE RIDGE OVER THE CENTRAL LAKES WILL
BUILD EAST AND TOWARDS THE REGION OVERNIGHT. THE CLEARING SKIES AND
VERY CHILLY/DRY AIRMASS WILL ALLOW TEMPERATURES TO DROP OVERNIGHT.
EXPECT LOWS IN THE LOWER 30S ON THE LAKE PLAINS WITH MID 20S IN THE
COOLER SOUTHERN TIER VALLEYS AND EAST OF LAKE ONTARIO.

ON THURSDAY THE SURFACE HIGH WILL BUILD SLOWLY EAST ACROSS THE LOWER
LAKES WITH A CONTINUATION OF DRY WEATHER. EXPECT A GOOD DEAL OF
SUNSHINE AS WELL...WITH JUST SOME PASSING HIGH CLOUDS MAINLY ACROSS
WESTERN NY AS WARM ADVECTION AND SOME LIMITED MOISTURE INCREASE IN
THE MID AND UPPER LEVELS. THE AIRMASS WILL BEGIN TO MODERATE...AND
WITH SUNSHINE EXPECT HIGHS TO MAKE IT INTO THE MID 50S IN MOST AREAS
BY MID TO LATE AFTERNOON. A NORTHWEST GRADIENT ONSHORE FLOW WILL
KEEP AREAS ALONG BOTH THE LAKE ONTARIO AND LAKE ERIE SHORELINE
COOLER.

THURSDAY NIGHT WILL START DRY AND MAINLY CLEAR TO PARTLY CLOUDY WITH
JUST A FEW HIGH CLOUDS CROSSING THE REGION. BY LATE THURSDAY NIGHT A
LEAD SHORTWAVE AND SURFACE WARM OCCLUSION WILL APPROACH THE FAR
WESTERN END OF THE STATE. INCREASING LARGE SCALE ASCENT AND
CONVERGENCE ALONG THE FRONTAL ZONE WILL BRING THICKENING CLOUDS FROM
WEST TO EAST LATE...WITH A FEW SHOWERS POSSIBLY REACHING THE FAR
WESTERN END OF THE STATE BY DAYBREAK FRIDAY. TEMPERATURES WILL NOT
BE AS COOL AS WEDNESDAY NIGHT...BUT WILL STILL DROP INTO THE 30S IN
MOST AREAS. THESE LOWS WILL OCCUR DURING THE FIRST HALF OF THE
NIGHT...WITH INCREASING SOUTHEAST FLOW AND WARM ADVECTION ALLOWING
TEMPERATURES TO RISE LATE.

ON FRIDAY THE MID LEVEL TROUGH WILL SWING ACROSS SOUTHERN ONTARIO
WITH THE SURFACE OCCLUDED FRONT PUSHING QUICKLY FROM WEST TO EAST
ACROSS THE AREA. THE SURFACE FRONT WILL RACE OUT AHEAD OF THE UPPER
LEVEL SUPPORT...WHICH SHOULD ALLOW SHOWERS TO DECREASE IN COVERAGE
AND INTENSITY AS THEY PUSH EAST ACROSS THE AREA. LATEST SREF MEANS
ONLY SUPPORT A RELATIVELY LOW CHANCE OF MEASURABLE RAIN ON FRIDAY.
WITH THIS IN MIND...HAVE JUST GONE WITH LOWER CHANCE POPS FOR FRIDAY
MOVING FROM WEST TO EAST ACROSS THE AREA. EVEN IF THE SHOWERS
MATERIALIZE...THEY SHOULD BE BRIEF WITH PLENTY OF RAIN FREE TIME AS
WELL. A PUSH OF SOMEWHAT WARMER AIR WILL ARRIVE WITH THIS SYSTEM...
AND SHOULD SUPPORT HIGHS INTO THE MID 60S ACROSS LOWER ELEVATIONS
AWAY FROM THE LAKESHORES.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MEDIUM RANGE MODEL GUIDANCE CONTINUES TO STRUGGLE WITH THE SYNOPTIC
SCALE DETAILS FOR NEXT WEEKEND...WITH BOTH THE GFS AND ECMWF SHOWING
FAIRLY WIDE SWINGS FROM RUN TO RUN. GIVEN THE MODEL DISAGREEMENT...
THE BEST COURSE OF ACTION IS TO STAY FAIRLY CLOSE TO THE PREVIOUS
FORECAST UNTIL BETTER MODEL CONSISTENCY IS SEEN.

LOOKING IN MORE DETAIL...THE GFS REMAINS MUCH FARTHER SOUTH WITH A
STRONG MID LEVEL TROUGH FRIDAY NIGHT AND SATURDAY AS IT SWINGS
THROUGH THE GREAT LAKES AND NEW ENGLAND. THE GFS IS ALSO MUCH
STRONGER WITH A SURFACE REFLECTION. THE ECWMF IS FARTHER NORTH WITH
THE MID LEVEL TROUGH AND MUCH WEAKER WITH THE SURFACE SYSTEM...
ALTHOUGH IT WOULD STILL PRODUCE A FEW SHOWERS SATURDAY. THE GEFS
ENSEMBLE MEMBERS SHOW A VARIETY OF SOLUTIONS RANGING FROM THE
OPERATIONAL GFS AND OPERATIONAL ECMWF TO EVERYTHING IN BETWEEN. IN
SHORT...CONFIDENCE IS FAIRLY HIGH ON SOME SORT OF SYSTEM FOR
SATURDAY BUT THE TRACK AND INTENSITY IS STILL VERY UNCERTAIN. WITH
THIS IN MIND HAVE JUST KEPT POPS IN THE HIGH CHANCE RANGE.
TEMPERATURES WILL BEGIN TO PULL BACK ON SATURDAY...WITH THE CORE OF
THE COOLDOWN LIKELY TO ARRIVE SATURDAY NIGHT AND SUNDAY. BY THIS
TIME THE NEW 12Z ECMWF HAS MADE A DRAMATIC CHANGE TO PREVIOUS
FORECASTS AND BECOMES OUT OF PHASE WITH THE GFS AND MOST ENSEMBLE
MEMBERS. THE NEW ECMWF BECOMES MUCH LESS AMPLIFIED WITH ITS
NORTHEAST CONUS TROUGH...WHICH ALLOWS THE CENTRAL CONUS CUTOFF TO
GET CLOSE ENOUGH TO PRODUCE SHOWERS SUNDAY AND MONDAY. GIVEN THE
MAJOR CHANGE FROM PREVIOUS RUNS...WE WILL DISCARD THE 12Z ECMWF
SOLUTION AND KEEP SUNDAY AND MONDAY MAINLY DRY. SUNDAY WILL LIKELY
BE THE COOLEST DAY BEFORE SOME MODERATION EARLY NEXT WEEK ALTHOUGH
TEMPERATURES WILL STILL REMAIN BELOW AVERAGE.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
A WIND SHIFT ASSOCIATED WITH A COLD FRONTAL BOUNDARY WILL KEY A
DRAMATIC IMPROVEMENT IN CONDITIONS. IFR OR LOWER CONDITIONS SHOULD
LINGER AT ART THROUGH MOST OF THE AFTERNOON HOURS AS DEW POINTS IN
THE UPPER 40S MOVE ACROSS THE COLD LAKE ONTARIO WATERS AND RESULT IN
LOW CIGS AND FOG. OTHERWISE...EXPECT SCATTERED SHOWERS BEHIND THE
FRONT FOR THE REMAINDER OF THE AFTERNOON HOURS WITH GENERALLY
IMPROVING CONDITIONS TO MVFR/VFR.

AFTER THIS...A SECONDARY UPPER LEVEL DISTURBANCE WILL BUILD INTO
THE REGION TONIGHT WHICH WILL INCREASE LOW LEVEL MOISTURE AND
LOWER CIGS. EXPECT A MIX OF MVFR/IFR CONDITIONS IN LOWERING CIGS.
THERE WILL ALSO BE SOME SHOWERS...WHICH WILL MIX WITH SNOW AT
TIMES...ESPECIALLY ACROSS HIGHER TERRAIN. CONDITIONS WILL IMPROVE
WEDNESDAY MORNING WITH THE EXIT OF THE SHORTWAVE...WITH WIDESPREAD
VFR CONDITIONS DEVELOPING BY WEDNESDAY AFTERNOON.

OUTLOOK...
WEDNESDAY NIGHT AND THURSDAY...VFR.
FRIDAY THROUGH SUNDAY...VFR/MVFR. A CHANCE OF SHOWERS.

&&

.MARINE...
SMALL CRAFT ADVISORIES ARE UP ON ALL OF THE LAKES...WITH A W-NW
FLOW BEHIND THE FRONT. THIS FLOW WILL BUILD WAVES TONIGHT AND
WEDNESDAY...ESPECIALLY DOWN THE LONGER FETCH OF LAKE ONTARIO. HIGH
PRESSURE WILL THEN BUILD ACROSS THE LAKES LATE WEDNESDAY AND
THURSDAY WITH A RETURN TO NON-SCA CONDITIONS.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EDT WEDNESDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR
         LOZ043>045.
         SMALL CRAFT ADVISORY UNTIL 11 PM EDT WEDNESDAY FOR LOZ042.

&&

$$

SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...APFFEL
MARINE...APFFEL







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