411  
FXUS61 KBUF 291533  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
1133 AM EDT TUE JUL 29 2014  
   
SYNOPSIS
 
 
COOL TEMPERATURES WILL REMAIN IN PLACE TODAY WITH THE CHANCE FOR  
SCATTERED AFTERNOON SHOWERS ACROSS WESTERN NEW YORK. THIS COOL  
PATTERN ALONG WITH CHANCES FOR SHOWERS WILL LAST THROUGH MUCH OF THE  
WEEK AS AN UPPER LEVEL AREA OF LOW PRESSURE HANGS OVER THE GREAT  
LAKES. WARMER AIR WILL RETURN BY THE WEEKEND BUT A LINGERING TROUGH  
ALOFT WILL CONTINUE CHANCES OF SHOWERS AND POSSIBLE THUNDERSTORMS.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
SURFACE TROUGHING IS FOUND ACROSS WESTERN NEW YORK THIS MORNING WITH A  
BROAD UPPER LEVEL LOW CONTINUING TO SPIN OVER THE GREAT LAKES AND  
NORTHEAST STATES. BOTH OF THESE FEATURES WILL CONTINUE THE CLOUDY  
SKIES FROM WESTERN NEW YORK EAST TO THE FINGER LAKES. DIURNAL  
INSTABILITY WILL PROVIDING SOME SCATTERED SHOWERS THIS AFTERNOON  
MAINLY ACROSS WESTERN NEW YORK. EAST OF LAKE ONTARIO...MUCH DRIER  
AIR ALOFT AS OBSERVED ON WATER VAPOR IMAGERY WILL KEEP JUST SCT/BKN  
FAIR WEATHER CLOUDS. TEMPERATURES TODAY WILL REMAIN NEAR 10 DEGREES  
BELOW LATE JULY AVERAGES. 12Z BUF RAOB MEASURES ONLY +6C AT 850MB  
WHICH IS ABOUT -2SD. HIGHS WILL TOP OUT IN THE UPPER 60S TO AROUND  
70 DEGREES WITH MID 60S ACROSS THE COLDER SPOTS.  
 
TONIGHT ANY DIURNAL SHOWERS WILL TAPER OFF WITH LINGERING LOW LEVEL  
CLOUD COVER. JULY LAKE EFFECT WILL AGAIN BECOME LIKELY AS BUFKIT  
PROFILES INDICATE INCREASING LAKE INDUCED CAPE TO 1500 J/KG AND  
EQUILIBRIUM LEVELS RISING OVER 30KFT. LAKE-850MB DELTA T'S WILL RISE  
OVER 13C. THIS INSTABILITY WILL COMBINE WITH A FORECASTED SURFACE  
TROUGH AND INCREASE IN LOW LEVEL MOISTURE FOR CELLULAR LAKE ENHANCED  
RAIN TO DEVELOP FIRST OFF LAKE ERIE BY DAYBREAK. A RISK FOR  
WATERSPOUTS WILL ALSO BE PRESENT. SURFACE TEMPS WILL AGAIN BOTTOM  
OUT IN THE LOW TO MID 50S OVERNIGHT.  
 

 
   
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 /16Z TUESDAY THROUGH SATURDAY/
 
 
BKN/OVC VFR CIGS REMAIN ACROSS MUCH WESTERN NEW YORK TODAY DO TO A  
COOL MOIST FLOW OFF OF THE LOWER GREAT LAKES BENEATH A TROUGH OF  
COLD AIR ALOFT. ONLY SCT VFR 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 HANG IN FOR MUCH  
OF THE DAY...WITH AGAIN THE EXCEPTION BEING THE EASTERN LAKE ONTARIO  
REGION. SCATTERED INSTABILITY SHOWERS WILL POP UP THIS AFTERNOON  
WITH THE HIGHEST CONFIDENCE AT KBUF/KIAG/KJHW WHERE VCSH HAS BEEN  
INCLUDED. EXPECT VFR CONDITIONS TONIGHT WITH CIGS GENERALLY RANGING  
BETWEEN 5 TO 10K FEET...WITH LOW VFR POSSIBLE BY THE END OF THE TAF  
PERIOD ACROSS WESTERN NY AS SOME LAKE ENHANCED CLOUDS AND SHOWERS  
DEVELOP EAST OF THE LAKES.  
 
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. COOL TEMPERATURES ALOFT  
WILL BRING A CHANCE WATERSPOUTS TUESDAY NIGHT THROUGH THURSDAY FOR  
BOTH LAKES ALONG WITH CHANCES OF LAKE ENHANCED SHOWERS.  
 

 
   
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...SMITH  
NEAR TERM...SMITH  
SHORT TERM...HITCHCOCK  
LONG TERM...HITCHCOCK  
AVIATION...SMITH  
MARINE...SMITH  
CLIMATE...THOMAS  
 
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