533  
FXUS61 KBUF 270826  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
426 AM EDT MON MAR 27 2017  
   
SYNOPSIS
 
 
TODAY, A WEAK AREA OF LOW PRESSURE WILL SLIDE EASTWARD, NORTH OF  
LAKE ONTARIO, WHILE PRODUCING MORNING RAIN SHOWERS ACROSS WESTERN  
NEW YORK, WITH ACTIVITY LINGERING INTO THE AFTERNOON HOURS ACROSS  
THE EASTERN LAKE ONTARIO REGION. MILD AIR TEMPERATURES WILL CONTINUE  
TODAY, THOUGH COOLER AIR WILL SLOWLY INCREASE ACROSS THE REGION  
THROUGH THURSDAY. ADDITIONAL RAIN SHOWERS TUESDAY WILL TAPER OFF  
TUESDAY NIGHT, TO BE THEN FOLLOWED BY A PERIOD OF DRY WEATHER  
WEDNESDAY AND THURSDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
SURFACE ANALYSIS THIS MORNING PLACES AN AREA OF LOW PRESSURE TO THE  
NORTHWEST OF LAKE ONTARIO. A LOOP OF WATER VAPOR IMAGERY SHOWS THE  
UPPER LEVEL LOW NEAR LAKE HURON, NEARLY OVER THE SURFACE LOW. A WEAK  
WARM FRONT EXTENDING FROM THIS LOW CROSSES WNY THIS MORNING, WITH  
RAIN SHOWERS LARGELY VIEWED ON REGIONAL RADARS TO THE NORTH AND EAST  
OF THIS FRONT.  
 
FOR TODAY AS THIS WARM FRONT LINGERS ACROSS OUR REGION, EXPECT  
NUMEROUS MORNING SHOWERS TO TAPER DOWN TO SCATTERED ACTIVITY, ENDING  
FROM WEST TO EAST AS THE SURFACE LOW TRACKS EASTWARD ACROSS SOUTHERN  
CANADA. RAINFALL FOR THE REST OF TODAY WILL RANGE FROM AROUND A  
TENTH OF AN INCH EARLY TODAY ACROSS WNY, AND UPWARDS TO A THIRD OF  
AN INCH ACROSS THE EASTERN LAKE ONTARIO REGION. RIVERS AND CREEKS  
WILL CONTINUE TO RUN HIGH, BUT NONE ARE EXPECTED TO OVERFLOW THEIR  
BANKS.  
 
BEHIND THIS WARM FRONT DEWPOINTS WILL RISE WELL INTO THE 40S ACROSS  
WNY, AND WINDS WILL VEER, FROM SOUTHERLY THIS MORNING, TO A  
SOUTHWEST FLOW BY MID TO LATE MORNING. THESE MOIST, SOUTHWEST WINDS  
OVER A STILL COOL LAKE ERIE MAY PRODUCE LOW CLOUDS AND FOG, THAT  
WILL ADVANCE INLAND, NORTHEASTWARD FROM LAKE ERIE THIS MORNING, AND  
POSSIBLY LINGER INTO THE EARLY AFTERNOON. IN ADDITION SOME PATCHY  
FOG WILL BE POSSIBLE ACROSS THE HILLS OF SW NYS TODAY...AND AS THIS  
MOISTURE WORKS ITS WAY EASTWARD, SOME FOG WILL BE POSSIBLE LATER  
TODAY AND TONIGHT ACROSS THE EASTERN LAKE ONTARIO REGION WHERE AREAS  
OF SNOW LINGER, AND THE GROUND REMAINS NEARLY FROZEN.  
 
TONIGHT A WEAKENING AREA OF LOW PRESSURE WILL ADVANCE ACROSS THE  
OHIO VALLEY. THIS FEATURE MAY BRING SEVERAL RAIN SHOWERS THAT WILL  
REACH WNY BEFORE SUNRISE TOMORROW.  
 
WITH LITTLE TO NO CHANGE IN AIRMASS EXPECTED TODAY...TEMPERATURES  
SHOULD AGAIN CLIMB INTO THE 50S ACROSS MOST AREAS...WHILE POSSIBLY  
REACHING THE 60F MARK AGAIN ACROSS FAVORED DOWNSLOPE FLOW REGIONS  
SOUTH OF LAKE ONTARIO. TONIGHT LOWS WITHIN A MOIST AIRMASS WILL DROP  
BACK INTO THE 40S.  
 

 
   
SHORT TERM /TUESDAY THROUGH THURSDAY/
 
 
A WEAKENING MID-LEVEL TROUGH WILL MOVE ACROSS THE REGION ON TUESDAY.  
00Z MODEL CONSENSUS HAS TRENDED SOUTH WITH THIS WAVE, WITH SOME  
MODEL GUIDANCE EVEN KEEPING NORTHERN PORTIONS OF THE CWA DRY.  
FOLLOWING THESE TRENDS, WILL MAINTAIN CATEGORICAL POPS SOUTH OF  
BUFFALO, BUT LOWER THESE TO THE NORTH. THIS WAVE SHOULD PRODUCE A  
FEW HOURS OF RAIN, MAINLY DURING THE MORNING AND EARLY AFTERNOON  
HOURS ON TUESDAY. THE DAY WILL BE FAR FROM A WASHOUT, WITH A PERIOD  
OF FAIRLY NICE WEATHER EXPECTED ACROSS WESTERN NEW YORK TUESDAY  
AFTERNOON. HIGHS WILL RANGE FROM THE MID TO UPPER 50S ACROSS WESTERN  
NEW YORK TO THE UPPER 40S TO LOWER 50S ACROSS THE EASTERN LAKE  
ONTARIO REGION.  
 
AFTER THIS, HIGH PRESSURE WILL EXPAND ACROSS ONTARIO PROVINCE  
TUESDAY NIGHT, WITH A RIDGE AXIS EXTENDING ACROSS THE LOWER GREAT  
LAKES REGION WEDNESDAY AND THURSDAY. A FEW LIGHT SHOWERS MAY LINGER  
TUESDAY NIGHT FROM RESIDUAL MOISTURE AND UPSLOPE ENHANCEMENT. THIS  
MAY MIX WITH SNOW ACROSS THE NORTH COUNTRY, WITH NO ACCUMULATION.  
AFTER THIS, THERE WILL BE AN EXTENDED PERIOD OF DRY WEATHER.  
 
UPSLOPE CLOUDS MAY LINGER TUESDAY NIGHT BUT SHOULD SCATTER OUT  
WEDNESDAY WITH TEMPERATURES ALOFT PROBABLY NOT COLD ENOUGH FOR LAKE  
EFFECT CLOUDS DESPITE THE NORTHERLY FLOW. WEDNESDAY WILL BE  
SEASONABLE WITH HIGHS IN THE 40S, AND THURSDAY A FEW DEGREES WARMER  
WITH SOUTHERN PORTIONS REACHING 50. THE RIDGE AXIS WILL BE ACROSS  
OUR REGION WEDNESDAY NIGHT, BUT THE SURFACE HIGH WILL BE TO OUR  
NORTH. EXPECT DECENT RADIATIONAL COOLING, BUT WINDS MAY NOT GO  
COMPLETELY CALM WITH LOWS IN THE MID 20S TO AROUND 30.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/
 
 
THE PATTERN WILL BECOME MORE ACTIVE AGAIN BY THE END OF THE WEEK  
AFTER A FEW DRY DAYS. A MID LEVEL CLOSED LOW WILL MEANDER ACROSS THE  
FOUR CORNERS REGION DURING THE FIRST HALF OF THE WEEK, THEN EJECT  
ENE ACROSS THE CENTRAL PLAINS TO THE OHIO VALLEY BY FRIDAY. 00Z  
GUIDANCE HAS COME INTO BETTER AGREEMENT, WITH THE ECMWF CLOSER TO  
THE 'WET' GFS/GGEM GUIDANCE. INCREASING WARM ADVECTION AND MOISTURE  
TRANSPORT AHEAD OF THIS TROUGH WILL LIKELY BRING SHOWERS THURSDAY  
NIGHT MAINLY IN WESTERN NY. THIS SYSTEM IS LIKELY TO BRING RAIN TO  
ALL AREAS FRIDAY AND FRIDAY NIGHT AS THE DEEP MID LEVEL TROUGH AND  
ASSOCIATED SURFACE LOW CROSS THE REGION. THE SYSTEM WILL BE FILLING  
WITH TIME, WHICH GENERALLY KEEPS FORCING AND MOISTURE TRANSPORT ON  
THE WEAKER SIDE WHICH WILL IN TURN KEEP RAIN AMOUNTS RELATIVELY  
MODEST.  
 
THIS SYSTEM WILL SLOWLY PULL OUT NEXT WEEKEND, WITH A FEW SCATTERED  
SHOWERS LINGERING INTO SATURDAY AS THE TROUGH AND SURFACE LOW MOVE  
TO THE EAST COAST, WITH NORTHWEST FLOW AND WRAP AROUND MOISTURE  
HANGING BACK ACROSS THE LOWER GREAT LAKES. MOISTURE AND RAIN CHANCES  
SHOULD DIMINISH BY SUNDAY AS THE TROUGH MOVES WELL OFF THE EASTERN  
SEABOARD.  
 
TEMPERATURES WILL LIKELY RUN NEAR TO SLIGHTLY ABOVE AVERAGE THROUGH  
THE PERIOD, WITH HIGHS GENERALLY IN THE UPPER 40S TO MID 50S AND  
LOWS IN THE 30S.  
 

 
   
AVIATION /09Z MONDAY THROUGH FRIDAY/
 
 
FOR THE 06Z TAFS SEVERAL WAVES OF RAIN SHOWERS WILL CONTINUE TO PASS  
ACROSS THE REGION OVER THE NEXT 12 HOURS. A SOUTHERLY WIND WILL  
MAINTAIN MOST TAF SITES MVFR OR GREATER IN FLIGHT CATEGORY THROUGH  
12Z, EXCEPT FOR KJHW WHERE LOW STRATUS AND IFR CEILINGS ARE EXPECTED  
TO CONTINUE THROUGH THE NIGHT AND THROUGH A GOOD PORTION OF THE DAY  
TODAY.  
 
THERE IS INCREASING CONFIDENCE THAT A PERIOD OF IFR FLIGHT  
CONDITIONS WILL BE POSSIBLE NORTHEAST OF LAKE ERIE BETWEEN 13Z AND  
18Z AS DEWPOINTS CLIMB, AND WINDS BECOME SOUTHWESTERLY. THIS WIND  
DIRECTION, TRANSPORTING MOISTURE OVER THE COOL LAKE WATERS MAY  
PRODUCE IFR FLIGHT CONDITIONS FOR KBUF/KIAG EITHER IN THE FORM OF  
LOW STRATUS OR BOTH LOW STRATUS AND FOG. AS WINDS VEER TO  
SOUTHWESTERLY LATER THIS AFTERNOON AND EVENING SOME IFR FLIGHT  
CONDITIONS WILL BE POSSIBLE ACROSS KART AS WELL.  
 
FLIGHT CONDITIONS WILL LARGELY REMAIN MVFR/VFR ACROSS KROC, AS LOW  
STRATUS FROM LAKE ERIE WILL LIKELY NOT EXTEND WELL INLAND OWING TO  
THE WEAK SYNOPTIC FLOW.  
 
WINDS WILL REMAIN LIGHT THIS PERIOD, AND DIMINISH TO LIGHT AND  
VARIABLE OVERNIGHT AS WEAK HIGH PRESSURE PUSHES TOWARDS THE REGION.  
THE WEAK FLOW, COUPLED WITH STILL PLENTY OF LOW LEVEL MOISTURE MAY  
ALLOW FOR SOME LOW STRATUS IN THE IFR/MVFR RANGE TO DEVELOP ACROSS  
THE REGION MONDAY NIGHT. IN ADDITION A FEW RAIN SHOWERS WILL REACH  
FAR WNY BY LATE IN THE NIGHT.  
 
OUTLOOK...  
 
TUESDAY...MVFR/IFR WITH OCCASIONAL SHOWERS.  
 
WEDNESDAY AND THURSDAY...VFR.  
 
FRIDAY...MVFR/IFR WITH SHOWERS LIKELY.  
 

 
   
MARINE
 
 
WILL CANCEL THE SMALL CRAFT ADVISORY WITH THIS UPDATE FOR THE LAKE  
ONTARIO REGION AS WINDS ASSOCIATED WITH A WEAK AREA OF LOW PRESSURE  
PASSING BY TO THE NORTH SHOULD REMAIN BELOW SCA THRESHOLDS.  
 
TODAY THROUGH THROUGH THURSDAY AN EXTENDED PERIOD OF BELOW SCA  
CONDITIONS ARE EXPECTED ON THE LAKES AS AN AREA OF HIGH PRESSURE  
WILL PRESS TOWARDS THE LAKES, BRINGING LIGHT WINDS.  
 

 
   
HYDROLOGY
 
 
FLOWS WILL REMAIN HIGH ON THE BLACK CREEK AND OATKA CREEK IN MONROE  
COUNTY. FORECAST POINTS AT CHURCHVILLE AND GARBUTT ARE JUST ABOVE  
ACTION STAGE AND NEAR CREST EARLY THIS MORNING. THEY SHOULD  
GRADUALLY FALL TODAY, WITH NO FLOODING EXPECTED.  
 

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

 
 

 
 
SYNOPSIS...THOMAS  
NEAR TERM...THOMAS  
SHORT TERM...APFFEL  
LONG TERM...APFFEL/HITCHCOCK  
AVIATION...THOMAS  
MARINE...THOMAS  
HYDROLOGY...APFFEL  
 
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