Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 281844
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
244 PM EDT THU APR 28 2016

.SYNOPSIS...
DISORGANIZED LOW PRESSURE WILL TRACK ACROSS THE OHIO VALLEY AND MID
ATLANTIC STATES THROUGH FRIDAY...WHILE PERIODICALLY BRINGING THE
OPPORTUNITY FOR SOME SHOWERS TO AREAS SOUTH OF LAKE ONTARIO. HIGH
PRESSURE WILL THEN BUILD BACK ACROSS THE REGION FRIDAY NIGHT AND
SATURDAY AND BRING A RETURN TO DRY WEATHER...BEFORE ANOTHER LOW
PRESSURE SYSTEM SPREADS SHOWERS BACK INTO THE REGION FOR SUNDAY AND
MONDAY. OTHERWISE...TEMPERATURES WILL GENERALLY CONTINUE TO RANGE
ON THE COOLER SIDE OF NORMAL RIGHT THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
DURING THIS PERIOD...A RATHER BROAD AND DISORGANIZED AREA OF LOW
PRESSURE OVER THE LOWER OHIO VALLEY WILL TRACK EASTWARD INTO
PENNSYLVANIA...WHILE GRADUALLY DEVOLVING INTO A LEFTOVER INVERTED
SURFACE TROUGH OVER PENNSYLVANIA AND NEW YORK. IN THE PROCESS...THIS
FEATURE WILL BRING PERIODIC OPPORTUNITIES FOR SOME SHOWERS TO AREAS
SOUTH OF LAKE ONTARIO.

THE FIRST OF THESE WILL COME FROM THIS AFTERNOON INTO EARLY THIS
EVENING...AS AN INITIAL SHOT OF DEEPER MOISTURE AND WEAK WARM
ADVECTIVE LIFT OUT AHEAD OF THE APPROACHING LOW SLIDES ACROSS
PENNSYLVANIA AND SOUTHERN PORTIONS OF NEW YORK STATE. THIS WILL
LEAD TO A LIKELIHOOD OF SOME LIGHT SHOWERS ACROSS THE SOUTHERN
TIER...ESPECIALLY IN AREAS CLOSE TO THE PENNSYLVANIA BORDER.
NORTH OF THIS...PROGRESSIVELY DRIER AIR AT THE LOWER LEVELS AND
DIMINISHING FORCING WILL GREATLY HINDER THE NORTHWARD ADVANCE OF
THE SHOWERS...WITH PRECIPITATION CHANCES SHARPLY DECREASING TO
SLIGHT CHANCE AND LOWER ALONG AND NORTH OF THE THRUWAY CORRIDOR...
AND TO NOTHING AT ALL ACROSS THE NORTH COUNTRY.

AS WE PROGRESS THROUGH THE EVENING AND EARLY OVERNIGHT HOURS...
THIS INITIAL SHOT OF WARM ADVECTION AND ASSOCIATED FORCING WILL
DEPART TO OUR EAST...AND WITH IT ANY SHOWER CHANCES SHOULD TEND
TO WANE ACROSS OUR REGION...WITH A RELATIVE LULL IN PRECIP THEN
LIKELY PERSISTING INTO FRIDAY MORNING GIVEN THE LACK OF ANY
FURTHER NOTEWORTHY LIFTING MECHANISMS THROUGH THAT TIME. HAVE
REFLECTED THIS IN THE FORECAST BY GRADUALLY DROPPING POPS BACK TO
LOW CHANCE ACROSS OUR SOUTHERNMOST TWO TIERS OF ZONES TONIGHT...
THEN HOLDING SUCH VALUES IN PLACE INTO FRIDAY MORNING.

THEN AS WE MOVE THROUGH FRIDAY...A COMPACT BUT FAIRLY VIGOROUS
MID AND UPPER LEVEL SHORTWAVE INITIALLY OVER THE UPPER GREAT LAKES
AT THE START OF THE DAY WILL SLIDE EASTWARD...AND INTO WESTERN
NEW YORK DURING THE AFTERNOON. AS THIS FEATURE APPROACHES...IT WILL
INTERACT WITH THE LINGERING INVERTED SURFACE TROUGH AND HELP TO
BRIEFLY REINVIGORATE IT...WHILE ALSO SUPPLYING A REINFORCING
SHOT OF MOISTURE AND LARGER-SCALE LIFT. ALL OF THIS WILL LIKELY
LEAD TO A SECOND ROUND OF SHOWERS SOUTH OF LAKE ONTARIO DURING
FRIDAY...WITH THE GREATEST LIKELIHOOD OF THESE AGAIN FOUND ACROSS
THE SOUTHERN TIER WHERE THE BEST COMBINATION OF MOISTURE AND
LARGE-SCALE ASCENT WILL BE IN PLAY. WHILE PRECIP CHANCES WILL
AGAIN TEND TO DIMINISH WITH INCREASING NORTHWARD EXTENT...THE
SUPPORTING MID AND UPPER LEVEL WAVE WILL LIKELY HELP PULL THESE
A BIT FURTHER NORTHWARD THAN TODAY...WITH LOWER-END CHANCES
EXTENDING AS FAR AS THE SOUTH SHORE OF LAKE ONTARIO. MEANWHILE...
THE NORTH COUNTRY AGAIN APPEARS VERY LIKELY TO REMAIN TOTALLY DRY.

ASIDE FROM THE ABOVE...A FAIR AMOUNT OF CLOUD COVER WILL REMAIN
IN PLACE ACROSS AREAS SOUTH OF LAKE ONTARIO TONIGHT AND FRIDAY...
WITH MAINLY CLEAR TO PARTLY CLOUDY SKIES ACROSS THE NORTH COUNTRY
TONIGHT GIVING WAY TO AT LEAST SOME INCREASE IN MID AND HIGH
CLOUDS ON FRIDAY AS THE AFOREMENTIONED SHORTWAVE APPROACHES.
THE INCREASED CLOUD COVER WILL RESULT IN MILDER OVERNIGHT LOWS
TONIGHT COMPARED TO THOSE OF LAST NIGHT...WITH READINGS RANGING FROM
THE LOWER 30S ACROSS THE NORTH COUNTRY TO THE 35-40 RANGE SOUTH
OF LAKE ONTARIO. CONVERSELY...THE INCREASED CLOUD COVER/PRECIP
CHANCES AND CONTINUED COOL NORTHEASTERLY FLOW WILL LEAD TO
ANOTHER DAY OF BELOW NORMAL TEMPERATURES ON FRIDAY...WHEN DAYTIME
HIGHS WILL RANGE FROM THE UPPER 40S AND LOWER 50S SOUTH OF LAKE
ONTARIO TO THE LOWER AND MID 50S ACROSS THE NORTH COUNTRY. JUST AS
IN THE PREVIOUS TWO DAYS...THE COOLEST OVERALL READINGS WILL BE
FOUND ALONG THE SOUTH SHORE OF LAKE ONTARIO...WHERE THE PREVAILING
FLOW OFF THE COOL LAKE WATERS WILL KEEP HIGHS CONFINED TO THE LOWER
TO MID 40S.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
THINGS WILL DRY OUT FRIDAY NIGHT INTO SATURDAY AS CANADIAN HIGH
PRESSURE PUSHES SOUTH ACROSS THE EASTERN GREAT LAKES...WITH WEAK MID
LEVEL RIDGING ARRIVING IN THE WAKE OF THE DEPARTING SHORTWAVE. THIS
PERIOD OF DRY WEATHER WILL BE SHORT LIVED AS IT LOOKS LIKE A PERIOD
OF RAIN WILL BECOME POSSIBLE AHEAD OF A WEAK WAVE MOVING INTO THE
OHIO VALLEY SATURDAY NIGHT.

LOW LEVEL JET AND AXIS OF STRONGEST MOISTURE TRANSPORT WILL BE
POSITIONED WELL WEST OF THE LOCAL AREA THROUGH MUCH OF SATURDAY
NIGHT...WITH LOW/MID LEVEL THETA E ADVECTION BEGINNING TO RAMP UP
ACROSS THE SOUTHERN TIER LATE SATURDAY NIGHT. CHANCES FOR RAIN WILL
INCREASE FROM SOUTH TO NORTH LATE SATURDAY NIGHT INTO SUNDAY DUE TO
THIS STRONG ADVECTIVE FORCING. WILL CONTINUE TO OMIT THUNDER MENTION
WITH FAIRLY DEEP/STABLE LAYER IN PLACE.

RAIN CHANCES WILL LINGER SUNDAY NIGHT AS UPPER TROUGHING DEVELOPS
FROM QUEBEC SOUTHWESTWARD INTO THE OHIO VALLEY. THIS WILL GRADUALLY
STRENGTHEN A SURFACE WAVE WHICH MOVES EAST OUT OF THE LOWER OHIO
VALLEY ACROSS THE APPALACHIANS PULLING A COLD FRONT THROUGH THE AREA.

SATURDAY LOOKS TO BE THE WARMEST OF THE TWO WEEKEND DAYS WITH MORE
SUNSHINE HELPING TO PUSH TEMPERATURES IN THE UPPER 50S TO LOWER
60S...PERHAPS MID TO UPPER 60S IN THE NORMALLY WARMER INTERIOR
LOCATIONS. CLOUDS AND RAIN WILL KEEP TEMPERATURES MUCH COOLER SUNDAY
WITH HIGHS LIKELY REMAINING IN THE 50S...WITH SOME AREAS POSSIBLY
STAYING IN THE 40S.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
00Z GUIDANCE BUILDS A BROAD AMPLIFIED TROUGH OVER THE GREAT LAKES
REGION THROUGH MUCH OF NEXT WEEK. THIS LEADS TO MORE CHANCES FOR
RAIN SHOWERS THROUGH MID TO LATE WEEK AS NORTHERN STREAM
SHORTWAVES PIVOT AROUND THE TROUGH IN THE WEST/NORTHWEST FLOW
ALOFT. TEMPERATURES WILL RUN JUST BELOW SEASONAL NORMALS INTO THE
START OF NEXT WEEK THEN LOOK TO WARM BACK TOWARDS NORMAL MID WEEK.
LOW TEMPERATURES LOOK TO ONLY SLIP BACK INTO THE 40S EACH NIGHT
WITH NO THREAT FOR FROST/FREEZE.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
DURING THE TAF PERIOD...A RATHER BROAD AND DISORGANIZED AREA OF
LOW PRESSURE OVER THE LOWER OHIO VALLEY WILL TRACK EASTWARD INTO
PENNSYLVANIA...WHILE GRADUALLY DEVOLVING INTO A LEFTOVER INVERTED
SURFACE TROUGH OVER PENNSYLVANIA AND NEW YORK. IN THE PROCESS...THIS
FEATURE WILL BRING PERIODIC OPPORTUNITIES FOR SOME SHOWERS. THE BEST
CHANCES FOR THESE WILL BE ACROSS THE SOUTHERN TIER BETWEEN THIS
AFTERNOON/EARLY THIS EVENING AND ACROSS AREAS SOUTH OF LAKE ONTARIO
FRIDAY AFTERNOON...WITH THE SOUTHERN TIER MOST LIKELY TO EXPERIENCE
SHOWERS IN BOTH CASES. THIS STATED...THE SHOWERS WILL LIKELY BE ON
THE LIGHT SIDE...AND THUS UNLIKELY TO PRODUCE ANY NOTEWORTHY
REDUCTIONS IN VSBYS.

AS FOR CIGS...THESE WILL GENERALLY HOLD STEADY OR SLOWLY LOWER
THROUGH THE PERIOD BUT WILL LARGELY REMAIN VFR. THE EXCEPTION TO
THIS WILL BE ACROSS THE WESTERN SOUTHERN TIER AND INTERIOR PORTIONS
OF THE FINGER LAKES...WHERE CIGS MAY LOWER TO MVFR TONIGHT AND FRIDAY.

OUTLOOK...
FRIDAY NIGHT...DIMINISHING SHOWERS WITH MVFR/VFR CIGS ACROSS THE
SOUTHERN TIER...AND VFR CONDITIONS ELSEWHERE.
SATURDAY...VFR.
SUNDAY...VFR/MVFR WITH SOME SHOWERS LIKELY.
MONDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
TUESDAY...MAINLY VFR.

&&

.MARINE...
A RATHER BROAD AND DISORGANIZED AREA OF LOW PRESSURE OVER THE LOWER
OHIO VALLEY WILL TRACK EASTWARD INTO PENNSYLVANIA THROUGH FRIDAY...
WHILE GRADUALLY DETERIORATING INTO A LEFTOVER INVERTED SURFACE TROUGH
OVER PENNSYLVANIA AND NEW YORK. THE PRESSURE GRADIENT BETWEEN THIS
SYSTEM AND HIGH PRESSURE OVER ONTARIO AND QUEBEC PROVINCES WILL
RESULT IN A GENERAL MODERATE NORTHEASTERLY FLOW CONTINUING ACROSS
THE LOWER LAKES REGION THROUGH FRIDAY. WHILE WINDS AND WAVES SHOULD
REMAIN BELOW ADVISORY LEVELS THROUGH FRIDAY IN MOST AREAS...THESE
WILL LIKELY INCREASE TO LOW-END SCA CRITERIA FOR A TIME LATER TONIGHT
AND FRIDAY ON WESTERN AND CENTRAL PORTIONS OF LAKE ONTARIO...FOR
WHICH A SMALL CRAFT ADVISORY HAS BEEN HOISTED.

FRIDAY NIGHT AND SATURDAY...HIGH PRESSURE WILL BUILD BACK ACROSS
THE LOWER GREAT LAKES...BRINGING A RETURN TO LIGHT TO MODEST
NORTHEASTERLIES AND CORRESPONDINGLY MINIMAL WAVES.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO 2 PM EDT FRIDAY FOR LOZ042-
         043.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...TMA
LONG TERM...CHURCH/SMITH
AVIATION...JJR
MARINE...JJR



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