674  
FXUS61 KBUF 210253  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
1053 PM EDT SUN APR 20 2014  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL CONTINUE TO DRIFT OFF AND AWAY FROM THE NORTHEAST  
COAST MONDAY BUT NOT BEFORE PROVIDING ONE MORE DRY AND WARM DAY. A  
COLD FRONT WILL CROSS THE REGION LATE MONDAY NIGHT AND TUESDAY WITH  
A PERIOD OF RAIN SHOWERS. THIS FRONT WILL USHER IN COOLER  
TEMPERATURES FOR THE MIDDLE OF THE WEEK BEFORE SOME REBOUND FOR  
THURSDAY AND FRIDAY.  
 

 
   
NEAR TERM /THROUGH MONDAY/
 
 
HIGH PRESSURE WILL CONTINUE TO DRIFT OFF AND AWAY FROM THE NORTHEAST  
COAST. MEANWHILE...A FEW WEAK MID LEVEL SHORTWAVES WILL TRAVERSE THE  
WESTERLY FLOW ALOFT THROUGH SOUTHEAST CANADA...AND COMBINE WITH  
INCREASING MID LEVEL WARM ADVECTION AND MOISTURE TO PRODUCE A FEW  
MID/HIGH CLOUDS OVERNIGHT. THE CLOUDS WILL BE MORE PREVALENT NEAR  
THE CANADIAN BORDER. EXPECT LOWS IN THE LOWER TO MID 40S ON THE LAKE  
PLAINS WITH MID 30S IN THE COOLER SOUTHERN TIER VALLEYS AND LEWIS  
COUNTY. SOUTHWEST RETURN FLOW WILL INCREASE SOME OVERNIGHT...SO  
EXPECT TEMPERATURES TO RISE LATE TONIGHT AS MIXING AND LOW LEVEL  
WARM ADVECTION INCREASE.  
 
ON MONDAY ONGOING DEEP SOUTHWEST FLOW AND WARM ADVECTION WILL BOOST  
850MB TEMPS TO AROUND +9C BY MID AFTERNOON ACROSS WESTERN NY AND  
ABOUT +7C ACROSS THE NORTH COUNTRY. WE HAVE NOTICED OVER THE PAST  
SEVERAL YEARS THAT WARM AIRMASSES DURING THE PRE GREEN-UP STAGE OF  
SPRING WILL OFTEN DELIVER WARMER TEMPERATURES THAN FORECAST BY MODEL  
GUIDANCE...DUE TO LACK OF TRANSPIRATION FROM PLANTS AND TREES. WITH  
THIS IN MIND HAVE GONE ABOVE EVEN THE WARMEST GUIDANCE...WITH HIGHS  
IN THE MID 70S AT LOWER ELEVATIONS AWAY FROM LAKE INFLUENCES...WITH  
MID TO UPPER 60S EAST OF LAKE ONTARIO. SOME OF THE WARMER LOCATIONS  
OF THE GENESEE VALLEY MAY REACH THE UPPER 70S.  
 
GRADIENT ONSHORE FLOW WILL KEEP THE LAKE ERIE SHORE COOLER AND ALSO  
AREAS NORTHEAST OF LAKE ONTARIO COOLER. MESOSCALE MODEL GUIDANCE  
SUCH AS OUR 6KM WORKSTATION WRF SUGGEST THE SYNOPTIC SCALE SOUTHWEST  
FLOW WILL NOT BE QUITE STRONG ENOUGH TO PREVENT A LAKE BREEZE FROM  
DEVELOPING ALONG PORTIONS OF THE SOUTH SHORE OF LAKE ONTARIO. THIS  
APPEARS MOST LIKELY FROM MONROE COUNTY EAST TO OSWEGO COUNTY WHERE  
THE SYNOPTIC FLOW IS A LITTLE WEAKER...SO HAVE GONE WITH COOLER  
TEMPS ALONG THE LAKESHORES OF THOSE COUNTIES.  
 
FINALLY...THERE MAY BE TWO SMALL AREAS WHERE WINDS BECOME A LITTLE  
BREEZY TOMORROW...DUE TO MORE UNIQUE MESOSCALE PROCESSES OF THE  
GREAT LAKES. BUFKIT PROFILES SUGGEST 20-25 KNOTS OF WIND A FEW  
THOUSAND FEET OF THE DECK. THESE STRONGER WINDS WILL NOT IMPACT  
LAKES ERIE OR ONTARIO...WHERE A DOME OF COOLER AND STABLE LAKE AIR  
WILL RESULT IN MUCH LIGHTER SURFACE WINDS. IMMEDIATELY DOWNWIND OF  
THESE STABLE LAKE DOMES...THE STRONGER WINDS WILL ESSENTIALLY  
DOWNSLOPE OFF THE STABLE LAKE DOMES...FOLLOWING ISENTROPIC SURFACES  
TO THE SURFACE. THIS OFTEN PRODUCES SMALL CORRIDORS OF SOMEWHAT  
STRONGER WINDS FROM ABOUT THE BUF AIRPORT NORTHEAST INTO GENESEE  
COUNTY...AND ALSO ACROSS CENTRAL AND NORTHEAST JEFFERSON COUNTY.  
WINDS MAY GUST TO AROUND 20 KNOTS IN THESE TWO AREAS ON MONDAY.  
 

 
   
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/
 
 
CLOUDS WILL THICKEN AND LOWER MONDAY NIGHT WITH RAIN SHOWERS  
ADVANCING TOWARD WESTERN NEW YORK AS A MID-LEVEL TROUGH AMPLIFIES  
WHILE SHIFTING EAST ACROSS THE WESTERN GREAT LAKES. AHEAD OF THIS  
AMPLIFYING TROUGH SURFACE LOW PRESSURE WILL SHIFT EAST ACROSS THE  
LOWER LAKES AND DEEPEN. SOUTHWESTERLY WINDS AHEAD OF THE LOW AND  
THICKENING CLOUD COVER WILL KEEP MILD TEMPERATURES OVERNIGHT RANGING  
IN THE MID TO UPPER 40S.  
 
TUESDAY MORNING A COLD FRONT EXTENDING SOUTH FROM THE LOW WILL CROSS  
WESTERN AND CENTRAL NEW YORK BRINGING RAIN SHOWERS. SOUTHWESTERLY  
MOISTURE TRANSPORT VECTORS JUST AHEAD OF THE FRONT WILL INCREASE  
PWATS TO JUST OVER ONE INCH WHICH IS ABOUT +1.5SD FOR MID TO LATE  
APRIL CLIMO SO HEAVY RAINFALL IS NOT EXPECTED. QPF IS A LITTLE  
HIGHER WITH 12Z RUNS AND IS EXPECTED TO RANGE 0.20-0.40 INCHES. WEAK  
NORTHWEST MOISTURE TRANSPORT OFF THE LAKES COMBINED WITH COLD AIR  
ADVECTION AND A TRAILING SURFACE TROUGH WILL KEEP CHANCES FOR  
SCATTERED RAIN SHOWERS IN THE FORECAST BEHIND THE COLD FRONT THROUGH  
THE REMAINDER OF THE DAY AND INTO TUESDAY NIGHT. THE THICK CLOUD  
COVER AND SHOWERS WILL KEEP TEMPERATURES A BIT COOLER THAN  
PREVIOUS DAYS WITH HIGHS ONLY RANGING IN THE LOW TO MID 50S.  
OVERNIGHT TUESDAY BUFKIT PROFILES CONTINUE TO SHOW WEAK SYNOPTIC  
LIFT AND LOW LEVEL MOISTURE REMAINING LIKELY ASSOCIATED WITH THE  
TRAILING SURFACE TROUGH WHICH WILL CONTINUE CHANCES OF SHOWERS.  
OVERNIGHT LOWS WILL FALL BACK INTO THE MID 30S WITH LOWER 30S FOUND  
ACROSS THE INTERIOR SOUTHERN TIER AND TUG HILL. THIS BRINGS A  
POSSIBILITY OF SOME SNOW FLAKES MIXING WITH ANY LINGERING RAIN  
SHOWERS ACROSS THE HILL TOPS.  
 
WEDNESDAY INTO WEDNESDAY NIGHT MODIFIED ARCTIC SOURCED HIGH PRESSURE  
WILL SETTLE ACROSS THE GREAT LAKES REGION. LINGERING CLOUD COVER  
WILL BE AROUND EARLY WEDNESDAY BUT MID-LEVEL DRYING AND SUBSIDENCE  
ASSOCIATED WITH THE HIGH PRESSURE WILL WORK TO CLEAR OUT SKIES WITH  
FULL SUNSHINE BREAKING OUT BY THE AFTERNOON HOURS AND CLEAR SKIES  
OVERNIGHT. 850MB TEMPS AROUND -5C WILL LIMIT DIURNAL HEATING AND  
KEEP OUR SURFACE HIGH TEMPS LIMITED TO ONLY THE MID TO UPPER 40S  
DESPITE FULL SUNSHINE DEVELOPING IN THE AFTERNOON. CLEAR  
SKIES...LIGHT WINDS AND A DRIER AIRMASS WILL HELP OVERNIGHT TEMPS TO  
FALL INTO THE LOW TO MID 30S WITH A POSSIBLE THREAT OF PATCHY FOG  
EARLY THURSDAY MORNING.  
 

 
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
 
A PROGRESSIVE MID-LEVEL FLOW IS FORECAST FOR LATE IN THE WEEK WITH A  
LOW AMPLITUDE TROUGH ACROSS THE WEST COAST WHICH WILL BUILD A RIDGE  
OVER THE GREAT LAKES. ALL 20/12Z MODEL PACKAGES ARE IN FAIR  
AGREEMENT THAT THE GREAT LAKES RIDGE WILL QUICKLY SHIFT OFF THE EAST  
COAST ON FRIDAY BEING REPLACED BY AN EXTENDED PERIOD OF TROUGHINESS  
INTO THE WEEKEND. THE LATE WEEK RIDGING AND SURFACE HIGH PRESSURE  
WILL BRING DRY WEATHER ON THURSDAY WITH TEMPERATURES RECOVERING BACK  
UP TO NEAR LATE APRIL NORMALS.  
 
THURSDAY NIGHT AND FRIDAY THE WESTERN TROUGH BUILDS ACROSS THE  
WESTERN GREAT LAKES AND CENTERS OVER THE LOWER GREAT LAKES. IN A  
SIMILAR PATTERN TO WHAT WE WILL SEE ON TUESDAY...A SURFACE LOW AND  
COLD FRONT WILL CROSS WESTERN AND CENTRAL NEW YORK BRINGING ANOTHER  
ROUND OF RAIN SHOWERS. A WARM AND MOIST SOUTHWEST AND WEST FLOW WILL  
HELP BOOST TEMPS ABOVE NORMAL WITH THE LEADING BAND OF RAIN SHOWERS  
FRIDAY. THIS WILL KEEP MID OVERNIGHT LOW TEMPS IN THE 40S ACROSS  
WESTERN NY BUT THE WARM AND MOIST AIR WILL NOT QUITE REACH THE  
EASTERN LAKE ONTARIO REGION WHERE LOWS WILL STILL DIP INTO THE 30S.  
HIGHS FRIDAY WILL CLIMB INTO THE LOW TO MID 60S FOR MUCH OF THE AREA  
BUT A LITTLE COOLER EAST OF LAKE ONTARIO.  
 
FRIDAY NIGHT THROUGH SUNDAY A NOW SLOWER MOVING MID-LEVEL TROUGH OF  
COOL AIR WILL KEEP UNSETTLED WEATHER OVER NEXT WEEKEND. CHANCES OF  
SHOWERS AND NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES ARE FORECAST  
FOR SATURDAY AND SUNDAY AS NORTHWEST FLOW WILL KEEP REINFORCING COLD  
ADVECTION ACROSS THE GREAT LAKES REGION. SATURDAY NIGHT TEMPERATURES  
MAY DROP TO NEAR OR JUST BELOW FREEZING ESPECIALLY ACROSS INLAND  
LOCATIONS AND HILLTOPS WITH A CHANCE FOR SOME SNOW AND RAIN SHOWERS  
OVERNIGHT.  
 

 
   
AVIATION /03Z MONDAY THROUGH FRIDAY/
 
 
VERY THIN CIRRUS CONTINUES TO DRIFT ACROSS THE REGION W/CONTINUED  
VFR AT ALL TAF SITES. OVERNIGHT A SERIES OF WEAK MID LEVEL  
DISTURBANCES WILL PASS BY JUST NORTH OF THE REGION AND BRING A  
MODEST INCREASE IN MID/HIGH CLOUDS WITH THE MOST CONCENTRATED CLOUD  
COVER NEAR THE CANADIAN BORDER AND NORTH COUNTRY THIS WILL CONTINUE  
THROUGH MONDAY WITH PERIODS OF MID LEVEL CLOUDS CROSSING LAKE  
ONTARIO AND THE NORTH COUNTRY...WITH INCREASING SUNSHINE FURTHER  
SOUTH NEAR THE PA STATE LINE.  
 
OUTLOOK...  
TUESDAY...AREAS OF MVFR WITH SHOWERS...IMPROVING TO VFR LATE.  
WEDNESDAY...A CHANCE OF A RAIN OR SNOW SHOWER WITH MVFR  
EARLY...OTHERWISE VFR.  
THURSDAY...VFR.  
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.  
 

 
   
MARINE
 
 
SURFACE HIGH PRESSURE WILL CONTINUE TO DRIFT OFF AND AWAY FROM THE  
NORTHEAST COAST THROUGH MONDAY AND REMAIN NEAR ENOUGH TO KEEP RELATIVELY  
LIGHT WINDS OVER THE LOWER LAKES. THE COLD LAKE WATERS WILL ALSO  
STABILIZE THE AIR OVER THE LAKES WITH LIGHTER WINDS DURING THE  
AFTERNOON THAN OVER LAND AREAS. LOCAL LAKE BREEZES WILL PRODUCE  
ONSHORE WINDS AGAIN MONDAY AFTERNOON.  
 
A COLD FRONT WILL CROSS THE REGION FROM WEST TO EAST TUESDAY  
MORNING. WINDS WILL INCREASE BEHIND THIS FRONT WITH CONDITIONS  
POSSIBLY APPROACHING SMALL CRAFT ADVISORY CRITERIA ON LAKE ONTARIO  
TUESDAY NIGHT AND WEDNESDAY.  
 

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

 
 

 
 
SYNOPSIS...AR/HITCHCOCK  
NEAR TERM...AR/HITCHCOCK  
SHORT TERM...SMITH  
LONG TERM...SMITH  
AVIATION...AR/HITCHCOCK  
MARINE...AR/HITCHCOCK  
 
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