957  
FXUS61 KBUF 291847  
AFDBUF  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BUFFALO NY  
247 PM EDT MON AUG 29 2016  
   
SYNOPSIS
 
 
SURFACE HIGH PRESSURE WILL MOVE ACROSS THE EASTERN GREAT LAKES  
REGION WITH COOLER TEMPERATURES AND MORE COMFORTABLE HUMIDITY  
TONIGHT AND TUESDAY. A COLD FRONT APPROACHES THE LOWER GREAT LAKES  
WEDNESDAY WITH A CHANCE OF SHOWERS AND THUNDERSTORMS. EXPANSIVE HIGH  
PRESSURE WILL AGAIN BUILD OVER THE GREAT LAKES AND NORTHEAST STATES  
WITH FINE WEATHER EXPECTED FOR THE LABOR DAY WEEKEND.  
 

 
   
NEAR TERM /THROUGH TUESDAY/
 
 
CURRENT SURFACE ANALYSIS PINS THE CENTER OF AN EXPANSIVE AREA OF  
HIGH PRESSURE JUST NORTH OF LAKE HURON THIS AFTERNOON WITH ITS  
INFLUENCE EXPANDED ACROSS THE GREAT LAKES AND OHIO VALLEY. SATELLITE  
AND SURFACE OBS SHOW LIGHT NORTH WINDS ARE ADVECTING IN A DRIER AND  
COOLER AIRMASS WITH BROKEN DIURNAL CLOUDS FOUND WHERE DEWPOINTS ARE  
STILL RUNNING IN THE 60S ACROSS THE FINGER LAKES WEST TO THE NIAGARA  
FRONTIER AND ACROSS THE HIGHER TERRAIN EAST OF LAKE ONTARIO. LAKE  
SHADOWS ARE PRESENT IMMEDIATELY SOUTH OF LAKE ONTARIO AND  
SENECA/CAYUGA LAKES. AS THE DRIER AIR CONTINUES TO SHIFT SOUTH  
ACROSS THE FORECAST AREA EXPECT COVERAGE OF THESE CLOUDS TO  
THIN/SHRINK BY SUNSET. HIGHS TODAY WILL PEAK IN THE UPPER 70S TO LOW  
80S WITH MUCH MORE COMFORTABLE HUMIDITY LEVELS.  
 
TONIGHT, THE CENTER OF THE HIGH PRESSURE IS EXPECTED TO SHIFT RIGHT  
OVER WESTERN NY WITH CLEAR SKIES AND LIGHT WINDS FOR MOST. THESE  
CONDITONS WILL SUPPORT RIVER VALLEY FOG DEVELOPMENT ACROSS THE  
SOUTHERN TIER. THE DRIER AIRMASS WITH DEWPOINTS SLIPPING BACK  
THROUGH THE 50S WILL SUPPORT A COOL NIGHT WITH LOWS DIPPING INTO THE  
50S FOR MOST LOCATIONS WITH A FEW UPPER 40S OVER THOSE COOLER  
SOUTHERN TIER VALLEYS.  
 
THE HIGH PRESSURE CENTER IS EXPECTED TO SHIFT ACROSS SOUTHERN NEW  
ENGLAND ON TUESDAY WITH ANOTHER SPLENDID DAY EXPECTED FOR WESTERN  
AND NORTH-CENTRAL NY. A DEVELOPING WEST-SOUTHWESTERLY FLOW IN THE  
LOW LEVELS WILL ALLOW TEMPERATURES TO WARM A BIT HIGHER WITH HIGHS  
FORECAST TO REACH INTO THE LOWER 80S. DEWPOINTS SHOULD REMAIN AT  
COMFORTABLE LEVELS IN THE 50S. A COLD FRONT WILL BE APPROACHING THE  
CENTRAL GREAT LAKES WITH THIN HIGH AND MID LEVEL CLOUDS ARRIVING  
ACROSS NEW YORK NORTHWEST TO SOUTHEAST LATER IN THE DAY.  
 

 
   
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/
 
 
A POTENT SHORTWAVE IN THE VICINITY OF JAMES BAY WILL PUSH A PATTERN  
CHANGING COLD FRONT SOUTHWARD TOWARDS OUR REGION TUESDAY NIGHT.  
WHILE THIS MOISTURE STARVED FRONTAL BOUNDARY COULD GENERATE A FEW  
SHOWERS NEAR LAKE ONTARIO AND ACROSS THE NORTH COUNTRY BEFORE  
DAYBREAK...THE OVERWHELMING MAJORITY OF THE REGION WILL BE RAINFREE  
WITH ONLY A GRADUAL INCREASE IN CLOUD COVERAGE.  
 
THE FRONT WILL THEN PASS THROUGH OUR FORECAST AREA DURING THE DAY  
WEDNESDAY. GIVEN THE RELATIVE LACK OF MOISTURE WITH THE FRONT...  
THERE SHOULD BE ENOUGH BREAKS IN THE ASSOCIATED CLOUD COVER TO ALLOW  
FOR SBCAPES TO CLIMB TO 500-1000 J/KG. IN ORDER TO SUPPORT SCATTERED  
CONVECTION...THIS INSTABILITY WILL CERTAINLY BE NEEDED TO OVERCOME  
AN OTHERWISE PALTRY AMOUNT OF SYNOPTIC LIFT ADVERTISED BY MOST OF  
THE GUIDANCE PACKAGES. WILL THUS KEEP LOW CHC POPS IN PLACE FOR THE  
BULK OF THE REGION...WITH ONLY SLIGHTLY HIGHER CHANCE FOUND EAST OF  
LAKE ONTARIO. TEMPERATURES WEDNESDAY AFTERNOON SHOULD AVERAGE WITHIN  
A COUPLE DEGREES OF 80.  
 
WHILE THE SFC FRONT WILL PUSH AWAY TO OUR SOUTH WEDNESDAY NIGHT...  
THE SUPPORTING MID LEVEL TROUGH WILL MAKE ITS WAY ACROSS THE LOWER  
GREAT LAKES. THE RESULTING CYCLONIC FLOW ALOFT WILL COMBINE WITH  
LIMITED LOW LEVEL MOISTURE TO KEEP SKIES FROM TOTALLY CLEARING  
OUT...ESPECIALLY IN THE FINGER LAKES REGION WHERE A NORTHERLY  
UPSLOPE FLOW IN THE LOW LEVELS WILL BE IN PLACE. IT SHOULD BE NOTED  
THAT WHILE IT WILL BE CHILLY ENOUGH ALOFT TO SUPPORT INSTABILITY  
OVER THE LAKES...THE SHORT FETCH AND LIMITED ENVIRONMENTAL MOISTURE  
WILL GREATLY REDUCE ANY LAKE RESPONSE.  
 
ON THURSDAY...A LARGE...FAR-REACHING AREA OF CANADIAN HIGH PRESSURE  
WILL EXTEND SOUTHWARD ACROSS THE UPPER GREAT LAKES TO THE SOUTHERN  
PLAINS WHILE THE AFOREMENTIONED MID LEVEL TROUGH WILL SLOWLY CROSS  
THE ST LAWRENCE VALLEY. THIS WILL GENERATE A RELATIVELY DEEP  
NORTHERLY FLOW OF MUCH COOLER AIR OVER OUR FORECAST AREA WITH H85  
TEMPS SETTLING TO AROUND 8C. AGAIN...WHILE THIS WILL KEEP  
INSTABILITY IN PLACE OVER THE LOWER GREAT LAKES...THE OVERALL REGIME  
WILL BE RELATIVELY DRY. WILL KEEP SOME CLOUDS IN PLACE ACROSS THE  
FINGER LAKES TO ACCOUNT FOR THE CONTINUED NORTHERLY UPSLOPE FLOW...  
OTHERWISE IT WILL BE A PARTLY SUNNY AND COOL DAY WITH MAX TEMPS  
GENERALLY WITHIN A FEW DEGREES OF 70.  
 
IT WILL BECOME RELATIVELY COOL FOR PARTS OF OUR FORECAST AREA  
THURSDAY NIGHT AS THE CENTER OF THE EXPANSIVE SFC HIGH WILL MAKE ITS  
WAY ACROSS THE UPPER GREAT LAKES. FAVORABLE RADIATIONAL COOLING  
WITHIN A FRESH CANADIAN AIRMASS WILL ALLOW THE MERCURY TO DROP WELL  
INTO THE 50S AWAY FROM THE LAKES...WITH PARTS OF THE SRN TIER LIKELY  
EXPERIENCING MINS IN THE 40S.  
 

 
   
LONG TERM /FRIDAY THROUGH MONDAY/
 
 
WHILE THE START OF THIS PERIOD WILL FEATURE COOL COMFORTABLE  
WEATHER...IT WILL BE MORE NOTEWORTHY TO POINT OUT THE SIGNIFICANT  
DAY TO DAY WARMING TREND THAT WILL CARRY US INTO NEXT WEEK. THE  
ULTIMATE FACTOR LEADING TO THE RETURN TO ABOVE NORMAL TEMPERATURES  
WILL BE THE DEVELOPMENT OF A STRONG JET ACROSS THE NORTHERN PACIFIC.  
THIS JET WILL KICK OUT PERSISTENT TROUGHINESS THAT WILL BE IN PLACE  
OVER BRITISH COLUMBIA...A TROUGH THAT WE HAVE NOT SEEN IN A COUPLE  
MONTHS AND AT LEAST PARTLY RESPONSIBLE FOR THE SPELL OF COOL  
WEATHER AT THE ONSET OF THIS PERIOD.  
 
IN ANY CASE...THE +120KT H25 JET WILL HELP TO DEAMPLIFY AND BROADEN  
THE WEST COAST TROUGH...WHICH IN TURN WILL LEAD TO SUBSTANTIAL  
HEIGHT RISES DOWNSTREAM ACROSS THE EASTERN HALF OF THE COUNTRY.  
MEANWHILE...EXPANSIVE HIGH PRESSURE WILL GUARANTEE RAIN FREE WEATHER  
THROUGH THE PERIOD. THE DETAILS...  
 
ON FRIDAY...A PROGRESSIVE UPPER-LEVEL TROUGH WITH HIGH-LATITUDE  
CANADIAN SOURCED AIR WILL PIVOT ACROSS NEW ENGLAND. A DRY...SHALLOW  
COOL AIRMASS WILL BUILD ACROSS THE REGION IN ITS WAKE WHILE A  
SPRAWLING SURFACE HIGH WILL MOVE FROM THE UPPER GREAT LAKES FRIDAY  
MORNING TO OVER THE FORECAST AREA FRIDAY NIGHT INTO SATURDAY  
MORNING. DESPITE 850 MB TEMPERATURES RETURNING TO AROUND +10C FRIDAY  
AFTERNOON...THE SHALLOW COOL AIRMASS WILL KEEP A LOW-LEVEL INVERSION  
IN PLACE AND THUS HIGH TEMPERATURES WILL REMAIN IN THE LOWER 70S. WE  
WILL SEE MUCH MORE SUNSHINE HOWEVER ON FRIDAY THOUGH...AS EVEN DRIER  
AIR WILL ADVECT ACROSS THE REGION.  
 
FRIDAY NIGHT WILL BE THE CHILLEST PERIOD OF THE FORECAST PACKAGE AS  
OPTIMAL RADIATIONAL (MINUS THE FRESH SNOWPACK) WILL ENCOURAGE OUR  
CANADIAN AIRMASS TO SUPPORT MINS IN THE LOW TO MID 40S ACROSS THE  
MAJORITY OF THE SOUTHERN TIER AS WELL AS IN LEWIS COUNTY. THE  
MERCURY WILL FLIRT WITH THE 40S ELSEWHERE AWAY FROM THE LAKES.  
 
TEMPERATURES WILL THEN RECOVER SATURDAY INTO SUNDAY AS THE SPRAWLING  
HIGH PRESSURE SYSTEM SLIDES OFF THE NEW ENGLAND COAST AND ALLOWS THE  
AIRMASS TO MODERATE WITH 850S BACK INTO THE MID TEENS C. THIS WILL  
BRING TEMPERATURES BACK INTO THE UPPER 70S SATURDAY AND LOW 80S  
SUNDAY AND POSSIBLY MID 80S BY LABOR DAY. WITH HIGH PRESSURE  
REMAINING IN CONTROL THIS SHOULD REMAIN A DRY PERIOD WITH FAIR  
WEATHER.  
 

 
   
AVIATION /19Z MONDAY THROUGH SATURDAY/
 
 
SCT/BKN VFR LOW LEVEL DIURNAL CLOUDS ARE FOUND SOUTH OF LAKE ONTARIO  
ACROSS THE FINGER LAKES AND EAST OF LAKE ONTARIO ACROSS THE HIGHER  
TERRAIN THIS AFTERNOON. EXPECT THESE CLOUDS TO THIN/ERODE BY SUNSET  
WITH AN INCOMING DRIER AIRMASS UNDER NORTHERLY FLOW.  
 
TONIGHT, UNDER CLEAR SKIES WITH EXCELLENT RADIATIONAL COOLING, HIGH  
CONFIDENCE THAT VALLEY FOG WILL DEVELOP ACROSS THE SOUTHERN TIER.  
THIS WILL PRODUCE LOWERING FLIGHT CONDITIONS MOST LIKELY AT KJHW  
WHERE IFR HAS BEEN INCLUDED.  
 
FOG WILL DISSIPATE TUESDAY AFTER 13-14Z WITH VFR EXPECTED THROUGH  
THE REMAINDER OF THE DAY.  
 
OUTLOOK...  
TUESDAY NIGHT AND WEDNESDAY...MAINLY VFR WITH A CHANCE OF  
SHOWERS AND THUNDERSTORMS.  
THURSDAY THROUGH SATURDAY...VFR.  
 

 
   
MARINE
 
 
HIGH PRESSURE WILL CROSS THE EASTERN GREAT LAKES REGION TONIGHT AND  
TUESDAY. THIS FEATURE WILL KEEP LIGHT WINDS AND WAVES THROUGH  
TUESDAY.  
 
A COLD FRONT WILL CROSS THE LAKES WEDNESDAY AND WEDNESDAY NIGHT AND  
THIS WILL KICK UP THE WINDS AND WAVES A BIT WEDNESDAY NIGHT AND INTO  
THURSDAY ON THE LAKES...THOUGH CONDITIONS MAY REMAIN JUST BELOW  
SMALL CRAFT CRITERIA. FINE BOATING CONDITONS ARE THEN EXPECTED  
THROUGH THE LABOR DAY WEEKEND AS ANOTHER EXPANSIVE AREA OF HIGH  
PRESSURE BUILDS ACROSS THE GREAT LAKES REGION.  
 

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

 
 

 
 
SYNOPSIS...SMITH  
NEAR TERM...SMITH  
SHORT TERM...RSH  
LONG TERM...RSH  
AVIATION...SMITH  
MARINE...SMITH  
 
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