000
FXUS61 KBUF 210822
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
422 AM EDT TUE MAY 21 2013

.SYNOPSIS...
A SOUTHWESTERLY FLOW OF WARM AND MORE HUMID AIR WILL CONTINUE ACROSS 
THE REGION FOR MUCH OF THIS WEEK...WHILE A FRONTAL BOUNDARY ALSO 
STALLS OUT ACROSS NEW YORK STATE AND SETS THE STAGE FOR PERIODIC 
ROUNDS OF SHOWERS AND THUNDERSTORMS. THE MORE UNSETTLED CONDITIONS 
WILL LAST THROUGH THURSDAY...BEFORE A COLD FRONT CROSSES THE AREA 
AND USHERS IN COOLER AND DRIER WEATHER FOR THE END OF THE WEEK AND 
THE MEMORIAL DAY WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 08Z...REGIONAL RADARS SHOW THAT THE INITIAL MCS HAS JUST 
EXITED THE AREA TO THE EAST...WHILE A SECOND AND SMALLER AREA OF  
SCATTERED CONVECTION CONTINUES TO MAKE ITS WAY EAST ACROSS LAKE 
ONTARIO...WHILE BRUSHING THE COUNTIES ALONG THE SOUTH SHORE OF THE 
LAKE IN THE PROCESS. THIS ACTIVITY IS SLIDING EAST ALONG A NEARLY 
STATIONARY FRONTAL BOUNDARY DRAPED ACROSS THE LENGTH OF LAKE 
ONTARIO...AND WILL CONTINUE TO DO SO THROUGH THE EARLY MORNING HOURS 
WHILE ALSO WEAKENING AS IT ENCOUNTERS PROGRESSIVELY LESS UNSTABLE 
AIR. WILL KEEP SOME CHANCE POPS IN PLAY TO COVER THE EASTWARD 
PROGRESS OF THIS ACROSS LAKE ONTARIO AND OUR ADJOINING COUNTIES... 
OTHERWISE THE REMAINDER OF THE AREA SHOULD STAY DRY AND WARM/HUMID.

ONCE THIS INITIAL ACTIVITY EXITS TO OUR EAST...EXPECT MOSTLY DRY/ 
SUNNY CONDITIONS TO BE THE GENERAL RULE FOR THE REST OF THE 
MORNING...WHICH WILL LEAD TO STRONG HEATING OF OUR RATHER WARM AND 
INCREASINGLY HUMID AIRMASS...AS MID-60 SFC DEWPOINTS ADVECT INTO THE 
REGION FROM THE OHIO VALLEY. AS WE GET INTO THE EARLY AFTERNOON 
HOURS...DEVELOPING AREAS OF CONVERGENCE ALONG LAKE BREEZE 
BOUNDARIES...TERRAIN FEATURES...AND THE DIFFUSE SURFACE FRONT WILL 
BEGIN TO LIFT THIS INCREASINGLY UNSTABLE AIR...AND SHOULD EVENTUALLY 
GENERATE SOME SCATTERED CONVECTION AS THE SOMEWHAT WEAKER MID LEVEL 
CAP THAT WILL BE IN PLACE COMPARED TO YESTERDAY IS OVERCOME. WITH 
THIS IN MIND...HAVE CONTINUED TO RAMP POPS BACK UP THROUGH THE 
CHANCE RANGE OVER TIME THIS AFTERNOON AS CONVECTIVE CHANCES 
INCREASE. 

FROM LATE THIS AFTERNOON INTO THIS EVENING...PRECIP PROBABILITIES 
SHOULD BE AT THEIR HIGHEST DUE TO THE COMBINATION OF THE 
AFOREMENTIONED DIURNALLY-DRIVEN CONVECTION...AND THE POSSIBILITY OF 
SOME ADDITIONAL UPSTREAM SHOWERS/STORMS ADVECTING EAST INTO THE AREA 
ALONG THE NEARLY STATIONARY FRONTAL BOUNDARY...AS SUGGESTED BY EACH 
OF THE GFS/GEM/ECMWF IN SOME FORM. WITH THE ABOVE IN MIND...WILL 
RESERVE THE HIGHEST POPS /LIKELIES/ FOR THIS TIME FRAME...WITH 
PRECIP CHANCES THEN DROPPING BACK TO THE CHANCE RANGE OVERNIGHT 
FOLLOWING THE PASSAGE OF A MID LEVEL SHORTWAVE...AND AS INSTABILITY 
WANES SOMEWHAT. 

WITH RESPECT TO TEMPERATURES...EXPECT WARM AND MUGGY CONDITIONS TO 
CONTINUE THROUGH THIS PERIOD. 850 MB TEMPS OF +15C TO +16C WILL ONCE 
AGAIN SUPPORT WIDESPREAD HIGHS IN THE LOWER TO MID 80S IN AREAS AWAY 
FROM ANY LAKE INFLUENCES TODAY...WITH LOWS IN THE LOWER TO MID 60S 
THEN FOLLOWING FOR TONIGHT.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
SUMMERY CONDITIONS WILL CONTINUE ACROSS OUR REGION ON WEDNESDAY...
AS A DEEP SOUTHERLY FLOW WILL REMAIN IN PLACE IN ADVANCE OF A
BROAD SFC LOW FOUND OVER LOWER MICHIGAN. WHILE IT WILL BE WARM AND
HUMID WITH TEMPERATURES RESEMBLING THOSE OF JULY...THERE WILL BE
SOME UNSETTLED WEATHER TO DEAL WITH AS WELL. OUR UNSTABLE AIRMASS
WILL CERTAINLY SUPPORT SOME SHOWERS AND THUNDERSTORMS...ALTHOUGH
THE BULK OF THE DAY MAY END UP BEING RAINFREE. LETS LOOK AT THE
PROS AND CONS TO THIS CONVECTION.

WORKING AGAINST WIDESPREAD CONVECTION WILL BE A SHORTWAVE RIDGE THAT 
WILL LIFT UP ACROSS OUR REGION. THIS COULD BE A DOUBLE EDGED SWORD 
THOUGH...AS THE RIDGE COULD HELP TO THIN SOME OF THE EXPECTED CLOUD 
COVER. THAT WOULD LEAD TO GREATER DIURNALLY INDUCED INSTABILITY THAN 
IS BEING FORECAST...WHICH IN TURN WOULD LIKELY LEAD TO MORE 
AFTERNOON CONVECTION. ON THE OTHER HAND...THE SUBSIDENCE FROM THE 
PASSING RIDGE IN TANDEM WITH MOSTLY CLOUDY SKIES COULD MINIMIZE THE 
THREAT OF STORMS (AS WAS ALSO EXPRESSED IN A PREVIOUS STORM  
PREDICTION CENTER DISCUSSION)...OR AT LEAST HOLD THEM OFF UNTIL MID 
TO LATE AFTERNOON.

EITHER WAY YOU SLICE IT...THERE SHOULD BE AT LEAST 500-1000 J/KG OF 
SBCAPE BY WEDNESDAY AFTERNOON SO THERE SHOULD BE SHOWERS OR 
THUNDERSTORMS TO DEAL WITH AS WE MOVE THROUGH THE DAY. THIS ACTIVITY 
WILL LIKELY FOCUS ON TWO AREAS. THE FIRST BEING A NEARLY STALLED 
FRONTAL BOUNDARY THAT WILL BE FOUND FROM THE NORTH SHORE OF LAKE 
ONTARIO TO THE NORTH COUNTRY...AND THE SECOND BEING A LAKE BREEZE 
BOUNDARY THAT SHOULD PUSH EAST OF LK ERIE. THE LATTER WOULD BE OF 
MORE CONCERN BECAUSE THIS WOULD BE THE TRIGGER TO RELEASE THE 
GREATER INSTABILITY OVER THE WRN COUNTIES. THIS LEADS US TO THE 
POTENTIAL FOR SEVERE WEATHER.

LETS STATE RIGHT UP FRONT THAT SPC HAS OUR FORECAST AREA OUTLINED IN 
A SLIGHT RISK FOR SEVERE STORMS ON WEDNESDAY. THAT BEING SAID AND 
AS WAS THE CASE IN YESTERDAYS MORNING DISCUSSION...AM NOT OVERLY 
IMPRESSED WITH THE OVERALL SET UP FOR SEVERE WEATHER. WE COULD HAVE 
SUPPRESSED INSTABILITY FROM CLOUD COVER AND ONGOING SHOWER 
ACTIVITY...BUT I AM JUST AS UNIMPRESSED WITH 0-3KM BULK SHEAR 
(GENERALLY <25 M/S) AND LACKLUSTER MID LEVEL LAPSE RATES OF 6 DEG 
C/KM. ONE HAS TO LOOK AT A DEEPER LAYER (0-6 KM) TO FIND IMPRESSIVE 
BULK SHEAR VALUES OF 35-40 M/S. A TELLING SIGN WILL LIKELY BE HOW 
MUCH SUN WE GET DURING THE MORNING AND MIDDAY. THE MAIN THREAT FROM 
ANY STRONG TO SEVERE STORMS WOULD BE STRAIGHT LINE WINDS...AND IF WE 
CAN GET OUR CAPES UP OVER 1500 J/KG...SOME LARGE HAIL. PWAT VALUES 
>1.5 INCHES WILL ALSO LIKELY LEAD TO SOME TORRENTIAL DOWNPOURS...
BUT THERE SHOULD BE ENOUGH WINDS TO MOVE THE STORMS ALONG AND 
MINIMIZE THE POTENTIAL FOR HYDRO ISSUES. BOILING THIS ALL DOWN... 
WILL USE LIKELY POPS BUT WILL REFRAIN FROM ADDING ANY ENHANCED TSRA 
WORDING. WILL DEFER THIS TO LATER SHIFTS FOR FURTHER REVIEW.

ON WEDNESDAY NIGHT...THE AFOREMENTIONED SFC LOW WILL TRACK BY TO OUR 
NORTH WHILE THE CONVECTION FROM THE EVENING HOURS WILL GRADUALLY 
SUBSIDE WITH THE LOSS OF DAYTIME HEATING AND SUBSEQUENT 
STABILIZATION OF THE LOWEST LEVELS. THIS WILL LEAVE A WARM AND DAMP 
NIGHT WITH NOCTURNAL TEMPERATURES ONCE AGAIN NOT FALLING OUT OF THE 
60S.

THE VARIOUS GUIDANCE PACKAGES THEN START TO DIVERGE ON THE HANDLING 
OF THE WAVY FRONTAL BOUNDARY THAT WILL OOZE ACROSS OUR FORECAST AREA 
ON THURSDAY. IN PREVIOUS MODEL RUNS...THE ECMWF HAS BEEN THE FASTER 
PACKAGE IN BRINGING THE FRONT THROUGH. IT NOW TRAILS THE GFS...AND 
FOR WHAT ITS WORTH...THE NAM. THE SECONDARY WAVE ALONG THE TRAILING 
FRONT IS WHAT IS OBVIOUSLY THROWING A MONKEY WRENCH INTO THE 
MODELS...BUT IN ANY CASE...THE MODELS ARE IN GENERAL AGREEMENT THAT 
THERE WILL BE A WEALTH OF LOW LEVEL MOISTURE THAT WILL BE LIFTED IN 
FAIRLY WIDESPREAD SHOWERS. JUST DO NOT SEE ENOUGH INSTABILITY TO 
HOLD ONTO THE SLGT CHC THAT WE HAVE FOR THUNDER...AS LAPSE RATES ARE 
GENERALLY BELOW 6 DEG C/KM BY MID MORNING. WILL COMPROMISE AND LEAVE 
THE MENTION FOR THE MORNING ONLY. OTHERWISE...IT WILL BE A WET AND 
NOTICEABLY COOLER DAY WITH TEMPERATURES AVERAGING SOME 10 DEG F 
LOWER THAN PREVIOUS DAYS. HIGHS SHOULD GENERALLY BE IN THE UPPER 60S 
TO LOWER 70S.

WHILE THE WAVY FRONT WILL BE WELL TO OUR EAST THURSDAY NIGHT...THE 
SUPPORTING H5 TROUGH WILL BE JUST CROSSING THE LOWER LAKES. THIS 
SHOULD KEEP SOME LEFTOVER SHOWERS OVER THE REGION...ESPECIALLY 
DURING THE FIRST HALF OF THE NIGHT. MEANWHILE...TEMPERATURES ARE 
EXPECTED TO TUMBLE INTO THE 40S...WHICH WILL BE QUITE REFRESHING 
AFTER SEVERAL DAYS OF MID JULY-LIKE WEATHER.

FRIDAY WILL FEATURE SEASONABLY COOL CONDITIONS AS H85 TEMPS IN THE 
VCNTY OF 4C WILL ONLY SUPPORT AFTERNOON HIGHS AROUND 60 F. WHAT IS 
MUCH LESS CERTAIN IS WHETHER ALL OF THE SHOWER ACTIVITY WILL BE 
DONE. THE 00Z GFS IS NOW BEING STUBBORN WITH CLEARING OUT THE 
SHOWERS AND LEFTOVER CLOUDS...SO WILL HAVE TO KEEP AT LEAST SLGT CHC 
POPS OVER THE REGION DURING THE MORNING AND INCREASE OUR CLOUD COVER 
A BIT. WILL STILL LEAN MORE ON THE ECMWF SOLUTION THOUGH...WHICH AT 
THIS POINT FAVORS A MORE OPTIMISTIC SCENARIO.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
PLENTY OF SUNSHINE AND SEASONABLY COOL TEMPERATURES WILL BE THE NAME 
OF THE GAME THIS WEEKEND AS HIGH PRESSURE WILL SETTLE ACROSS THE 
GREAT LAKES. 850MB TEMPS DROPPING TO AROUND 0C SHOULD ONLY YIELD 
HIGHS TOPPING OUT IN THE LOWER 60S FOR MOST AREAS ON SATURDAY... 
NEARLY 10 DEGREES BELOW NORMAL. LIKEWISE OVERNIGHT LOWS WILL RUN ON 
THE CHILLY SIDE WITH READINGS IN THE LOWER 40S ALONG THE LAKE PLAINS 
WHILE AREAS FARTHER INLAND ACROSS THE SOUTHERN TIER AND NORTH 
COUNTRY COULD DROP INTO MID 30S...POTENTIALLY SETTING THE STAGE FOR 
A FROST...PARTICULARLY SATURDAY NIGHT WHEN THE SURFACE HIGH IS 
FORECAST TO BE OVERHEAD. 

A GRADUAL REBOUND IN TEMPERATURES IS EXPECTED FOR THE LATTER HALF OF 
THE WEEKEND AS THE COLDEST AIR ASSOCIATED WITH THE UPPER LEVEL 
TROUGH DEPARTS THE REGION AND WARMER AIR BEGINS TO CREEP NORTH FROM 
THE OHIO VALLEY ONCE AGAIN. OTHERWISE...EXPECT DRY WEATHER TO 
CONTINUE THROUGH THE END OF THE WEEKEND.

&&

.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
AS OF 08Z...REGIONAL RADARS SHOW THAT THE INITIAL MCS HAS JUST 
EXITED THE AREA TO THE EAST...WHILE A SECOND AND SMALLER AREA OF  
SCATTERED CONVECTION CONTINUES TO MAKE ITS WAY EAST ACROSS LAKE 
ONTARIO...WHILE ALSO BRUSHING THE COUNTIES ALONG THE SOUTH SHORE OF 
THE LAKE IN THE PROCESS. THIS ACTIVITY IS SLIDING EAST ALONG A 
NEARLY STATIONARY FRONTAL BOUNDARY DRAPED ACROSS THE LENGTH OF LAKE 
ONTARIO...AND WILL CONTINUE TO DO SO THROUGH THE EARLY MORNING HOURS 
WHILE ALSO WEAKENING AS IT ENCOUNTERS PROGRESSIVELY LESS UNSTABLE 
AIR. EXPECT THE POSSIBILITY OF SOME LOCALIZED IFR/MVFR WITHIN THESE 
SCATTERED SHOWERS/STORMS AS THEY SLIDE EASTWARD...WITH VFR 
CONDITIONS OTHERWISE EXPECTED ACROSS THE REMAINDER OF THE AREA.

ONCE THIS AREA SLIDES OFF TO OUR EAST...EXPECT MAINLY DRY VFR 
CONDITIONS TO PREVAIL THROUGH THE REST OF THE MORNING...WITH 
SCATTERED CONVECTION THEN DEVELOPING ACROSS INTERIOR SECTIONS AND 
ALONG LAKE BREEZE BOUNDARIES DURING THE AFTERNOON...SOME OF WHICH 
COULD PRODUCE ADDITIONAL BRIEF LOCALIZED REDUCTIONS TO IFR/MVFR. 

TONIGHT...SOME ADDITIONAL UPSTREAM CONVECTION MAY RIDE EAST ALONG A 
STALLED OUT FRONTAL BOUNDARY AND CROSS THE AREA FROM WEST TO EAST 
THIS EVENING...BEFORE SOMEWHAT QUIETER WEATHER RETURNS FOR THE 
OVERNIGHT HOURS. 

OUTLOOK...  
WEDNESDAY THROUGH THURSDAY...SCATTERED TO NUMEROUS SHOWERS AND 
THUNDERSTORMS WITH ASSOCIATED MVFR/IFR...OTHERWISE VFR. 
FRIDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
SATURDAY...VFR.

&&

.MARINE...
THROUGH THURSDAY...WINDS WILL REMAIN RELATIVELY LIGHT AND VARIABLE 
IN DIRECTION DUE TO A NEARLY STATIONARY FRONTAL BOUNDARY THAT WILL 
REMAIN DRAPED ACROSS THE REGION...AS WELL AS THE DAILY DEVELOPMENT 
OF LAKE BREEZES. AS A RESULT...WAVE HEIGHTS SHOULD ALSO REMAIN 
RELATIVELY MINIMAL. OTHERWISE...EXPECT A CONTINUED POTENTIAL FOR 
SHOWERS AND THUNDERSTORMS THROUGH THURSDAY...SOME OF WHICH MAY 
PRODUCE LOCALLY HIGHER WINDS AND WAVES.

LOOKING A BIT FURTHER OUT...A COLD FRONTAL PASSAGE THURSDAY NIGHT 
WILL RESULT IN WINDS VEERING TO A NORTHERLY DIRECTION ALONG WITH AN 
INCREASE IN WAVE HEIGHTS...ESPECIALLY ALONG THE SOUTH SHORES OF THE 
LAKES WHERE SMALL CRAFT ADVISORIES MAY EVENTUALLY BE NEEDED LATER 
THURSDAY NIGHT/FRIDAY MORNING.

&&

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

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH/WOOD
AVIATION...JJR
MARINE...JJR