Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 281601
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1201 PM EDT THU AUG 28 2014

.SYNOPSIS...
COOLER AIR WILL CONTINUE TO POUR IN ACROSS THE REGION TODAY...WITH A
RETURN TO BELOW NORMAL TEMPERATURES BEFORE TEMPERATURES RETURN TO
NEAR NORMAL FRIDAY. THE NEXT OPPORTUNITY FOR PRECIPITATION WILL ARRIVE
FOR THE LABOR DAY WEEKEND...WHEN A COMPLEX FRONTAL SYSTEM WILL
SLOWLY MOVE ACROSS THE REGION.

&&

.NEAR TERM /THROUGH TONIGHT/...
CLEARING IS UNDERWAY ACROSS THE NIAGARA FRONTIER AS THE HEART OF THE
COLD POOL ALOFT...AND THE ASSOCIATED LAKE RESPONSE...MAKE THEIR WAY
EAST ACROSS THE AREA. WITH THE COLDEST AIR ALOFT MOVING EAST...WE
SHOULD SEE THE CLEARING TREND CONTINUE ACROSS THE NIAGARA FRONTIER
AND ALONG LAKE ONTARIO THIS AFTERNOON AS DRIER AIR WORKS ITS WAY
INTO THE AREA...HOWEVER FARTHER INLAND THE INCREASING INSOLATION
WILL ALLOW FOR BREAKS IN THE SOLID CLOUD COVER ON THE ONE HAND...BUT
ON THE OTHER HAND WILL ALLOW FOR DIURNALLY DRIVEN STRATO-CU TO
LINGER THROUGH THE AFTERNOON...PARTICULARLY EAST OF THE GENESEE
VALLEY CLOSER TO THE CENTER OF THE COLD POOL ALOFT. BREAKS OF SUN
WILL NOT BE ENOUGH TO OFFSET THE COOL AIR ADVECTION THROUGHOUT THE
DAY...WITH HIGHS IN THE UPPER 60S TO AROUND 70.

HIGH PRESSURE WILL CREST OVER THE REGION TONIGHT PROVIDING LIGHT
WINDS WITH CLEARING SKIES ACROSS THE REGION AS THE DIURNALLY DRIVEN
INSTABILITY DIMINISHES. LATE TONIGHT CLEAR SKIES AND LIGHT WINDS
WILL MEAN EXCELLENT RADIATIONAL COOLING CONDITIONS FOR TYPICAL
VALLEY FOG TO FORM ACROSS PORTIONS OF THE WESTERN SOUTHERN TIER.
EXPECT A COOL LATE SUMMER NIGHT ACROSS THE AREA WITH LOWS GETTING
DOWN INTO THE MID TO UPPER 40S ACROSS THE HIGHER TERRAIN OF THE
WESTERN SOUTHERN TIER AND EASTERN LAKE ONTARIO REGION. EXPECT LOWS
MAINLY IN THE LOWER 50S OVER LOWLAND AREAS...WITH MID 50S BEING
FOUND RIGHT ALONG THE LAKE SHORES.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
FRIDAY HIGH PRESSURE WILL BUILD FROM THE LOWER LAKES IN THE MORNING
TO OFF THE NEW ENGLAND COAST BY EVENING AS A MID LEVEL RIDGE BUILDS
OVERHEAD. WARM ADVECTION WILL INCREASE AROUND THE WESTERN PERIPHERY
OF THE DEPARTING HIGH...ALLOWING TEMPERATURES TO RECOVER SOME AFTER
A COOL THURSDAY. EXPECT HIGHS IN THE MID TO UPPER 70S ACROSS WESTERN
NY...WITH LOWER 70S ON THE HILLS AND EAST OF LAKE ONTARIO. CLEAR
SKIES IN THE MORNING WILL GIVE WAY TO SOME INCREASE IN MID/HIGH
CLOUD COVER DURING THE DAY IN RESPONSE TO WARM ADVECTION...MAINLY
FROM THE GENESEE VALLEY WESTWARD.

A POORLY DEFINED WARM FRONT WILL LIFT NORTHEAST ACROSS THE REGION
FRIDAY NIGHT AND BRING A PERIOD OF ISENTROPIC UPGLIDE AND ENHANCED
CONVERGENCE AND MOISTURE. A WEAK MID LEVEL VORTICITY MAXIMA WILL
ALSO TRAVERSE THE NORTHERN EDGE OF THE RIDGE...PROVIDING SOME WEAK
LARGE SCALE ASCENT. THE COMBINATION OF WARM ADVECTIVE FORCING AND
MOISTURE MAY BE ENOUGH TO PRODUCE A FEW SPRINKLES FRIDAY NIGHT IN
SOME AREAS ALONG WITH INCREASED CLOUD COVER. THE BEST CHANCE FOR ANY
MEASURABLE SHOWERS WILL BE OVER AND EAST OF LAKE ONTARIO OVERNIGHT
INTO SATURDAY MORNING WHERE LATEST MODEL GUIDANCE SHOWS ASCENT AND
MOISTURE MAXIMIZED. THE INCREASE IN CLOUD COVER AND RETURN FLOW WILL
KEEP TEMPERATURES MILDER...WITH LOWS IN THE LOWER 60S ON THE LAKE
PLAINS OF WESTERN NY AND MID TO UPPER 50S IN THE COOLER INTERIOR
SOUTHERN TIER AND EAST OF LAKE ONTARIO.

ON SATURDAY THE RETREATING WARM FRONT MAY PRODUCE A FEW SHOWERS IN
THE MORNING ACROSS THE NORTH COUNTRY WITH ONGOING WARM ADVECTION AND
ENHANCED MOISTURE CONVERGENCE. ELSEWHERE THE MORNING SHOULD BE
MAINLY DRY AS THE WARM SECTOR BECOMES ESTABLISHED. BY AFTERNOON THE
COMBINATION OF DIURNAL SURFACE HEATING AND INCREASING BOUNDARY LAYER
MOISTURE WILL CONTRIBUTE TO MODERATE INSTABILITY...WITH SBCAPE IN
MODEL GUIDANCE REACHING THE 1500-2000J/KG RANGE. MID LEVEL
TEMPERATURES WILL BE ON THE WARM SIDE WHICH MAY HOLD ONTO SOME CINH
INITIALLY...BUT CONVERGENCE ALONG LAKE BREEZE AND TERRAIN BOUNDARIES
SHOULD BE SUFFICIENT TO FORCE WIDELY SCATTERED DEEP MOIST CONVECTION
DURING THE AFTERNOON...WITH THE GREATEST CHANCES ACROSS THE SOUTHERN
TIER AND FINGER LAKES. SOUTHWEST FLOW OFF BOTH LAKES SHOULD ALLOW
STABLE LAKE SHADOWS TO DEVELOP...WITH A MUCH LESSER CHANCE OF ANY
SHOWERS OR STORMS NEAR KBUF AND KART. 850MB TEMPS NEAR 17C WILL
SUPPORT HIGHS IN THE MID TO UPPER 80S AT LOWER ELEVATIONS ACROSS
WESTERN NY...WITH LOWER 80S ACROSS THE SOUTHERN TIER HILLS AND EAST
OF LAKE ONTARIO.

THE BEST CHANCE OF SOMEWHAT MORE WIDESPREAD SHOWERS AND STORMS NOW
APPEARS TO BE SATURDAY NIGHT INTO EARLY SUNDAY MORNING WHEN A LOW
AMPLITUDE MID LEVEL SHORTWAVE WILL CROSS THE LOWER LAKES...WITH AN
ATTENDANT BELT OF 30+ KNOT 900-700MB FLOW ENHANCING CONVERGENCE
ALONG A PRE-FRONTAL TROUGH. THERE WILL BE AMPLE MOISTURE TO WORK
WITH AS PWAT RISES TO NEAR 2 INCHES. GIVEN THE COMBINATION OF
FORCING... MOISTURE...AND LINGERING INSTABILITY WILL GO WITH LIKELY
POPS FOR LATER SATURDAY NIGHT ACROSS THE ENTIRE REGION...WITH LIKELY
POPS LASTING INTO SUNDAY MORNING ACROSS THE EASTERN HALF OF THE
AREA. MODEL GUIDANCE HAS BEEN SHOWING A GOOD DEAL OF VARIANCE WITH
RESPECT TO THE TIMING OF THIS FEATURE AND THUS THE BEST CHANCES OF
RAIN OVER THE WEEKEND...BUT MOST GUIDANCE APPEARS TO NOW BE FOCUSING
ON THIS PERIOD.

BY SUNDAY AFTERNOON DOWNWARD VERTICAL MOTION BEHIND THE WEAK MID
LEVEL TROUGH SHOULD ALLOW SHOWERS AND STORMS TO BECOME MORE WIDELY
SCATTERED IN NATURE...ALTHOUGH DIURNAL INSTABILITY WILL PROBABLY
KEEP AT LEAST A FEW GOING. STABLE LAKE SHADOWS MAY DEVELOP DURING
THE AFTERNOON WITH THE KBUF AND KART AREAS SEEING THE LOWEST CHANCE
OF RAIN ONCE AGAIN AND EVEN SOME SUNSHINE. 850MB TEMPS GET KNOCKED
BACK A LITTLE FOLLOWING THE TROUGH PASSAGE...SO EXPECT HIGHS IN THE
LOWER TO MID 80S IN MOST AREAS.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
SUNDAY NIGHT A MID LEVEL TROUGH WILL EXIT ACROSS SOUTHERN QUEBEC
WITH A FLAT MID LEVEL RIDGE BUILDING TEMPORARILY ACROSS THE LOWER
LAKES. THIS SHOULD BRING AT LEAST A REDUCTION IN THE COVERAGE OF
CONVECTION ACROSS THE REGION...ALTHOUGH A FEW SHOWERS OR AN ISOLATED
THUNDERSTORM MAY LINGER. GIVEN THE UNCERTAINTY IN TIMING OF
INDIVIDUAL SHORTWAVE FEATURES AT THIS LEAD TIME WILL KEEP LOW CHANCE
POPS FOR SUNDAY NIGHT. ON LABOR DAY MONDAY ANOTHER WEAK SURFACE AND
MID LEVEL TROUGH WILL MOVE INTO THE GREAT LAKES REGION AND SUPPORT A
FEW MORE SHOWERS AND THUNDERSTORMS...WITH THE BEST CHANCES LATER IN
THE DAY AND INTO MONDAY NIGHT. DESPITE THE RAIN CHANCES THERE SHOULD
BE LENGTHY RAIN FREE PERIODS AS WELL. THIS TROUGH WILL EXIT ON
TUESDAY WITH A LOW CHANCE OF A LINGERING SHOWER OR STORM.

THE 00Z GFS AND ECMWF BOTH BUILD SURFACE HIGH PRESSURE INTO THE
LOWER LAKES BY TUESDAY NIGHT AND WEDNESDAY WITH A RETURN TO DRY
WEATHER.

TEMPERATURES THROUGH THE LONG TERM PERIOD WILL START A LITTLE ABOVE
AVERAGE ON MONDAY WITH HIGHS IN THE LOW TO MID 80S BEFORE PULLING
BACK INTO THE 70S BY MIDWEEK AS A BUBBLE OF COOLER AND DRIER AIR
BUILDS INTO THE GREAT LAKES REGION.

&&

.AVIATION /16Z THURSDAY THROUGH MONDAY/...
INCREASING INSOLATION AND ADVECTION OF DRIER AIR INTO THE REGION IS
HELPING TO MIX OUT CLOUD COVER ACROSS THE NIAGARA FRONTIER THIS
MORNING. EXPECT THIS CLEARING TREND TO HOLD THROUGHOUT THE AFTERNOON
AT KBUF/KIAG/KROC. FARTHER INLAND AND ACROSS THE NORTH
COUNTRY...DIURNALLY DRIVEN STRATO-CU WILL KEEP A SCT-BKN VFR DECK IN
PLACE THROUGH THE AFTERNOON...PARTICULARLY SOUTH AND EAST OF KROC
WHERE A COLD POOL OF AIR ALOFT WILL ADD TO THE INSTABILITY...THOUGH
NOT ENOUGH TO GENERATE ANY PRECIPITATION.

CLEARING SKIES CAN BE EXPECTED AS HIGH PRESSURE MOVES OVERHEAD AND
DIURNAL HEATING DISSIPATES. THE EXCEPTION WILL BE ACROSS THE WESTERN
SOUTHERN TIER WHERE THE COMBINATION OF CLEAR SKIES AND LIGHT WINDS
WILL MAKE FOR GOOD RADIATIONAL COOLING ALLOWING FOR TYPICAL VALLEY
FOG TO FORM...POSSIBLY IMPACTING KJHW WITH MVFR OR IFR VISIBILITY
LATE TONIGHT.

OUTLOOK...
FRIDAY THROUGH FRIDAY NIGHT...VFR.
SATURDAY THROUGH SUNDAY...MAINLY VFR WITH CHANCE OF
SHOWERS/THUNDERSTORMS.
MONDAY...VFR/MVFR IN SCATTERED SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
NORTHWEST FLOW WILL AVERAGE AROUND 10 KNOTS TODAY...WITH SLIGHTLY
HIGHER WINDS OF AROUND 15 KNOTS ACROSS THE EASTERN END OF LAKE
ONTARIO THANKS TO A LONGER FETCH. WAVES 2 FEET OR LESS ON LAKE ERIE
WILL ALSO SUBSIDE AS WINDS DIMINISH SOME AS THE PRESSURE GRADIENT
RELAXES TODAY.

&&

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

&&

$$

SYNOPSIS...JM
NEAR TERM...JM/WOOD
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...JM/WOOD
MARINE...JM/WOOD







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