Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 290920
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
520 AM EDT TUE JUL 29 2014

.SYNOPSIS...
DRIER COOLER WEATHER WILL RETURN FOR TUESDAY...WITH THE CHANCE FOR
SCATTERED AFTERNOON SHOWERS ACROSS WESTERN NEW YORK. THIS COOLER
PATTERN WITH CHANCES FOR SHOWERS WILL LAST THROUGH MID WEEK. THEN
DRIER WEATHER ALONG WITH TEMPERATURES MODERATING BACK TO NEAR NORMAL
LEVELS WILL OCCUR BY THE END OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AT 09Z REGIONAL RADARS SHOWING THE ONLY SHOWER ACTIVITY IS WELL
UPSTREAM OVER THE UPPER GREAT LAKES. ANOMALOUSLY DEEP UPPER TROUGH
WILL REMAIN OVER THE EASTERN US THROUGH THE PERIOD. MEANWHILE A WEAK
RIDGE OF SURFACE HIGH PRESSURE WILL NOSE IN ACROSS THE REGION THIS
MORNING PROVIDING DRY WEATHER AND CLOUDS MIXED WITH SUN. DIURNAL CU
WILL BE ON THE INCREASE THIS AFTERNOON. SCATTERED SHOWERS WILL
LIKELY DEVELOP ACROSS WESTERN NEW YORK IN PART DUE TO SURFACE
HEATING. THIS ALONG WITH DEEPER WRAP AROUND MOISTURE COMBINED WITH
COOL TEMPERATURES ALOFT AND A WEAK UPPER LEVEL SHORTWAVE PASSING
OVER THE AREA WILL HELP AID IN THE DEVELOPMENT OF THESE SHOWERS.

TUESDAY NIGHT WILL START OUT MAINLY DRY WITH INCREASING CHANCES FOR
LAKE ENHANCED SHOWERS ACROSS FAR WESTERN NEW YORK TOWARD DAYBREAK
WEDNESDAY.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AN ANOMALOUSLY DEEP LONGWAVE TROUGH WILL DOMINATE THE NORTHEAST
QUARTER OF THE NATION THROUGH THE SHORT TERM PERIOD. A SERIES OF
LOWER AMPLITUDE SHORTWAVES WILL ROTATE ACROSS THE GREAT LAKES WITHIN
THE MEAN LONGWAVE TROUGH AND PROVIDE SEVERAL PERIODS OF ENHANCED
LARGE SCALE ASCENT AND MOISTURE. THE AIRMASS IS ALSO COOL ENOUGH TO
SUPPORT LAKE EFFECT OR ENHANCED RAIN AT TIMES.

LOOKING AT THE DETAILS...ON WEDNESDAY A WEAK MID LEVEL SHORTWAVE AND
LOW LEVEL TROUGH WILL CROSS THE LOWER LAKES FROM WEST TO EAST. THE
SYNOPTIC SYSTEM ITSELF WILL BE WEAK AND MAY ONLY PRODUCE A FEW
WIDELY SCATTERED SHOWERS OUTSIDE OF LAKE EFFECT AREAS. THE LAKES
WILL COME INTO PLAY DURING THE FIRST HALF OF THE DAY HOWEVER...WITH
VERY IMPRESSIVE LAKE INDUCED CAPE OF 1200-1500J/KG AND EQUILIBRIUM
LEVELS GREATER THAN 30K FEET. THE STRONG LAKE INDUCED INSTABILITY
COMBINED WITH SOME SYNOPTIC SCALE ASCENT WILL LIKELY PRODUCE LAKE
EFFECT SHOWERS WEDNESDAY MORNING. LAKE EFFECT AT THIS TIME OF YEAR
IS ALMOST ALWAYS ORGANIZED INTO CELLULAR CONVECTION RATHER THAN A
SINGLE BAND...GIVEN HOW DEEPLY MIXED THE BOUNDARY LAYER IS IN SUMMER.

OFF LAKE ERIE...EXPECT A BROKEN BAND OF SHOWERS TO EXTEND OFF THE
LAKE INTO THE NIAGARA FRONTIER AT 12Z WED. THESE SHOWERS WILL LIKELY
DETACH FROM THE LAKE BY MID TO LATE MORNING WITH THE ONSET OF
DAYTIME HEATING AND EASTWARD PROGRESSION OF THE LOW LEVEL
TROUGH...SPREADING SHOWERS EAST ACROSS THE REMAINDER OF THE AREA.
OFF LAKE ONTARIO...EXPECT SHOWERS TO BE LOCATED OVER THE LAKE TO
NEAR PRINCE EDWARD POINT AT 12Z WED...SPREADING EAST INTO THE
EASTERN LAKE ONTARIO REGION AS THE MORNING PROGRESSES. GIVEN THE
QUALITY OF INSTABILITY FORECAST...THERE MAY BE SCATTERED
THUNDERSTORMS AND HEAVY DOWNPOURS WITHIN THE LAKE BANDS AS WELL.

BY WEDNESDAY AFTERNOON EXPECT THE LAKES TO TRY TO FLIP...WITH LAKE
EFFECT SHOWERS AND INSTABILITY IN THE MORNING TENDING TO EVOLVE INTO
DIURNAL SHOWERS INLAND FROM THE LAKES DURING THE AFTERNOON. THERE
COULD STILL BE A FEW ISOLATED TO WIDELY SCATTERED THUNDERSTORMS
WEDNESDAY AFTERNOON. GIVEN THE COLD AIR ALOFT AND STEEP LAPSE RATES
ANY STORM MAY PRODUCE SMALL HAIL.

WEDNESDAY NIGHT INTO THURSDAY MORNING THE AIRMASS WILL STILL BE COOL
ENOUGH TO SUPPORT A LAKE RESPONSE...WITH SHOWERS TENDING TO FOCUS
OVER AND EAST OF THE LAKES AGAIN. THERE MAY STILL BE ENOUGH
INSTABILITY LEFT FOR A FEW ISOLATED THUNDERSTORMS AND LOCAL HEAVY
DOWNPOURS. OVERALL COVERAGE OF SHOWERS DURING THIS PERIOD SHOULD BE
LESS THAN THAT OF WEDNESDAY. FINALLY THURSDAY NIGHT THE LONGWAVE
TROUGH WILL BEGIN TO PULL OUT INTO QUEBEC...ALLOWING FOR SOME DRYING
TO TAKE PLACE ACROSS THE LOWER LAKES. EXPECT MOST LOCATIONS TO BE
DRY OVERNIGHT WITH PARTIAL CLEARING. THERE MAY STILL BE A LINGERING
SHOWER ACROSS THE NORTH COUNTRY IN CLOSER PROXIMITY TO THE DEPARTING
TROUGH.

TEMPERATURES WILL CONTINUE TO RUN BELOW AVERAGE THROUGH THE PERIOD.
HIGHS ON WEDNESDAY WILL BE IN THE LOW TO MID 70S ACROSS LOWER
ELEVATIONS AND UPPER 60S ACROSS HIGHER TERRAIN...WITH THURSDAY
ADDING ON A FEW MORE DEGREES. OVERNIGHT LOWS WILL BE COOL...BUT
CLOUD COVER WILL LIMIT RADIATIONAL COOLING POTENTIAL. EXPECT LOWS IN
THE MID TO UPPER 50S ON THE LAKE PLAINS AND LOWER 50S INLAND.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
THE LONGWAVE TROUGH OVER THE EAST WILL FINALLY PULL AWAY ENOUGH INTO
QUEBEC ON FRIDAY TO BRING A BRIEF RETURN TO MAINLY DRY WEATHER.
TEMPERATURES WILL CONTINUE TO MODERATE BACK TO NEAR AVERAGE.

THE DRY WEATHER WILL BE SHORT LIVED HOWEVER AS THE TROUGH RELOADS
ACROSS THE GREAT LAKES BY SATURDAY. INCREASING SOUTHERLY FLOW AHEAD
OF THE NEXT DIGGING TROUGH WILL ALLOW DEEPER MOISTURE TO ADVECT
NORTHWARD ALONG THE EAST COAST AND APPALACHIANS...REACHING OUR
REGION BY FRIDAY NIGHT OR SATURDAY. THIS WILL ALLOW SCATTERED
SHOWERS AND THUNDERSTORMS TO DEVELOP...WITH THE GREATEST COVERAGE
LIKELY TO BE ACROSS THE HIGHER TERRAIN OF THE SOUTHERN TIER AND
FINGER LAKES...AND ALSO EAST OF LAKE ONTARIO. THIS SAME BASIC
PATTERN WILL CONTINUE INTO SUNDAY AS THE MID LEVEL TROUGH SLOWLY
CROSSES THE LOWER LAKES.

MODEL UNCERTAINTY INCREASES BY MONDAY AS THE GFS AND ECMWF DIVERGE
ON THE TIMING OF THE NEXT SYSTEM. THE ECMWF IS FASTER IN BRINGING
ANOTHER NORTHERN STREAM TROUGH INTO THE GREAT LAKES LATER MONDAY
AFTERNOON...WHILE THE GFS HOLDS THIS SYSTEM BACK ACROSS THE WESTERN
LAKES ON MONDAY. FOR NOW WILL GO WITH THE MORE OPTIMISTIC GFS
SOLUTION AND KEEP MONDAY DRY.

TEMPERATURES WILL BE BACK TO TYPICAL MID SUMMER LEVELS FROM THE
WEEKEND INTO EARLY NEXT WEEK WITH LOWER 80S AT LOWER ELEVATIONS ON
MOST DAYS.

&&

.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
AT 09Z CIGS REMAIN AT 4K-6K FEET ACROSS MUCH OF THE AREA THANKS TO A
COOL MOIST FLOW OFF OF THE LOWER GREAT LAKES. WESTERLY UPSLOPE FLOW
ACROSS THE WESTERN SOUTHERN TIER HAS A FEW LOCATIONS WITH CIGS DOWN
TO 1-2K FT. LESSER AMOUNTS OF CLOUDS ARE FOUND TOWARD THE EASTERN
LAKE ONTARIO REGION DUE TO THE LACK OF LAKE INFLUENCE WITH A
NORTHWEST FLOW IN PLACE. EXPECT CLOUD COVERAGE TO THIN OUT SOME
THROUGH MID TO LATE MORNING. THEN SCATTERED DIURNAL CU WITH 4 TO 6K
FEET BASES WILL DEVELOP LATE THIS MORNING INTO THE AFTERNOON...ALONG
WITH SCATTERED SHOWERS ACROSS PORTIONS OF WESTERN NEW YORK. EXPECT
VFR CONDITIONS TONIGHT WITH CIGS GENERALLY RANGING BETWEEN 5 TO 10K
FEET FOR MOST OF THE NIGHT...WITH LOW VFR POSSIBLE BY THE END OF THE
TAF PERIOD ACROSS WESTERN NY.

WESTERLY SURFACE WINDS TODAY WILL BE 5 TO 10 KNOTS...BECOMING
SOUTHWESTERLY LATER IN THE DAY. TONIGHT WINDS WILL BE SOUTH TO
SOUTHWEST BETWEEN 5 TO 10 KNOTS.

OUTLOOK...
WEDNESDAY AND THURSDAY...VFR/MVFR WITH SCATTERED SHOWERS.
FRIDAY...VFR
SATURDAY...MAINLY VFR WITH CHANCE SHOWERS AND THUNDERSTORMS.

&&

.MARINE...
A WEAKER FLOW IS FORECAST THROUGH MID-WEEK. COOLER TEMPERATURES
ALOFT SUGGEST THERE IS A CHANCE FOR WATERSPOUTS TUESDAY NIGHT
THROUGH THURSDAY FOR BOTH LAKES.

&&

.CLIMATE...
RAINFALL THE PAST TWO DAYS HAS VARIED WIDELY FROM AROUND A HALF INCH
FOR PORTIONS OF THE SOUTHERN TIER...TO AROUND AN INCH NEAR LAKE ERIE
AND EAST OF LAKE ONTARIO TO SIGNIFICANT RAINFALL TOTALS ACROSS THE
GENESEE VALLEY. FOR OUR CLIMATE STATION IN ROCHESTER NEW YORK THIS
TWO- DAY RAINFALL EVENT HAS BROUGHT SOME NOTE WORTHY CLIMATE
STATS.

EVENT RAINFALL SUNDAY AND THROUGH 4 PM MONDAY TOTALED 3.84 INCHES OF
RAIN IN ROCHESTER. THERE WAS 1.42 INCHES OF RAIN ON SUNDAY...AND A DAILY
RECORD OF 2.42 INCHES OF RAIN THROUGH 4 PM MONDAY.

THIS 2-DAY OR "48-HOUR" EVENT TOTAL OF 3.84 INCHES PLACES 6TH
WETTEST OF ALL 2-DAY RAINFALL TOTALS IN ROCHESTER`S HISTORY. BELOW
ARE THE TOP WETTEST 2-DAY TOTALS IN ROCHESTER`S HISTORY WHICH DATES
BACK TO 1871.


1   4.96 INCHES     OCTOBER 19-20 1873
2   4.21 INCHES     AUGUST 27-28 1871
3   4.20 INCHES     JUNE 6-7 1980
4   4.19 INCHES     AUGUST 28-29 1893
5   3.85 INCHES     MAY 16-17 1974
6   3.84 INCHES     JULY 27-28 2014


THE RECENT RAINS HAVE ALSO BUMPED ROCHESTER INTO A TOP 5 WETTEST
JULY ON RECORD. BELOW ARE A LISTING OF THE TOP 5 WETTEST JULYS ON
RECORD FOR ROCHESTER NEW YORK:

RANK    PRECIPITATION   YEAR
         (INCHES)

1       9.70            1947
2       8.08            1945
3       8.02            2006
4       7.51            2014
5       6.37            1897

THERE ARE STILL SEVERAL DAYS REMAINING IN JULY...THUS THE FINAL JULY
2014 PRECIPITATION TOTAL MAY INCREASE.

&&

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

&&

$$

SYNOPSIS...JM
NEAR TERM...JM
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...JM
MARINE...JM
CLIMATE...THOMAS






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