Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 131146
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
746 AM EDT SUN JUL 13 2014

.SYNOPSIS...
A FRONTAL SYSTEM WILL CROSS THE REGION TODAY AND TONIGHT...BRINGING
MORE HUMID CONDITIONS ALONG WITH SOME SHOWERS AND THUNDERSTORMS.
CONTINUED UPPER LEVEL TROUGHING WILL THEN KEEP AT LEAST SOME
ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS GOING RIGHT THROUGH
TUESDAY...BEFORE DRIER AND COOLER WEATHER RETURNS FOR THE SECOND
HALF OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
THROUGH THE COURSE OF TODAY...LOW PRESSURE WILL LIFT FROM NEAR LAKE
HURON NORTHEASTWARD TOWARD JAMES BAY. IN THE PROCESS...IT WILL PIVOT
ITS ASSOCIATED WARM FRONT ACROSS THE AREA BETWEEN THIS MORNING AND
EARLY THIS AFTERNOON...BEFORE QUICKLY SWINGING ITS TRAILING COLD
FRONT INTO WESTERN PORTIONS OF THE AREA BY EARLY THIS EVENING. AS
THIS SYSTEM WORKS EASTWARD...EXPECT THE POTENTIAL FOR SHOWERS AND
EMBEDDED THUNDERSTORMS TO INCREASE FROM WEST TO EAST THIS MORNING
WITH THE APPROACH AND PASSAGE OF THE WARM FRONT. AS THESE ARRIVE...
EXPECT ROUGHLY A THREE TO FOUR HOUR-LONG WINDOW OF SHOWERS AND
POSSIBLE EMBEDDED THUNDER AT ANY GIVEN LOCATION...WITH SOME OF THESE
CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL GIVEN PWATS CLIMBING TO
THE VICINITY OF 2 INCHES.

ONCE THIS INITIAL ROUND OF CONVECTION AND ASSOCIATED CLOUD COVER
CLEARS THE AREA...EXPECT DIURNAL HEATING TO LEAD TO AT LEAST SOME
DESTABILIZATION THIS AFTERNOON IN ADVANCE OF THE APPROACHING COLD
FRONT...WHICH SHOULD EVENTUALLY LEAD TO AT LEAST SOME SCATTERED
ADDITIONAL CONVECTION DEVELOPING ALONG AND INLAND FROM A DEVELOPING
LAKE BREEZE BOUNDARY ACROSS WESTERN NEW YORK. THE BIG QUESTION AT
THIS POINT REMAINS EXACTLY HOW MUCH WE WILL DESTABILIZE...AS PLENTY
OF SHEAR WILL BE IN PLACE TO SUPPORT THE DEVELOPMENT OF STRONG TO
SEVERE SURFACE-BASED STORMS INLAND FROM THE LAKES SHOULD ENOUGH
INSTABILITY ACTUALLY BE REALIZED...WITH STRONG DAMAGING WINDS BEING
THE PRIMARY SEVERE WEATHER THREAT SHOULD THESE ACTUALLY OCCUR.
AT THIS POINT...FEEL THAT THIS POTENTIAL IS LESSENING GIVEN THAT WE
SHOULD HAVE FAIRLY PLENTIFUL CLOUD COVER AND SCATTERED TO NUMEROUS
SHOWERS IN PLACE THROUGH AT LEAST THE MIDDAY TO EARLY AFTERNOON
HOURS...THOUGH HAVE STILL LEFT A MENTION OF GUSTY WINDS IN THE
FORECAST TO COVER THIS POSSIBILITY.

AS WE GET INTO TONIGHT...THE TRAILING COLD FRONT WILL SLOWLY EASE
ITS WAY SOUTHEASTWARD ACROSS OUR REGION. WHILE THE LOSS OF HEATING
WILL RESULT IN NOCTURNAL STABILIZATION AND LOWERING POTENTIAL FOR
STRONG TO SEVERE STORMS...WITH A WARM AND VERY HUMID AIRMASS STILL
IN PLACE CHANCES FOR SOME ADDITIONAL SCATTERED CONVECTION WILL
LINGER UNTIL THIS BOUNDARY PASSES.

WITH RESPECT TO TEMPERATURES...HIGHS TODAY SHOULD GENERALLY RANGE IN
THE UPPER 70S TO LOWER TO MID 80S...WITH THE WARMEST READINGS ACROSS
THOSE LOWER ELEVATIONS NOT IMPACTED BY THE SOUTHWESTERLY FLOW OFF
THE LAKES. LOWS TONIGHT WILL THEN DROP BACK INTO THE LOWER TO MIDDLE
60S FOLLOWING THE COLD FRONTAL PASSAGE.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
A HIGHLY ANOMALOUS UPPER LEVEL PATTERN DURING THIS SHORT TERM PERIOD
WILL SET THE STAGE FOR SOME VERY COOL WEATHER DURING THE MID AND
LATTER PORTIONS OF THE WEEK. HGT AND TEMP DEPARTURES WITHIN THIS
PATTERN WILL BE HIGHLIGHTED BY 3 STD ANOMALIES IN A VERY ROBUST WEST
COAST RIDGE WITH CORRESPONDINGLY LOW VALUES OVER THE MISSISSIPPI
VALLEY. THESE ARE DEPARTURES THAT HAVE A RETURN INTERVAL OF ONCE IN
A GREATER THAN 30 YEAR PERIOD.

WHILE THIS PATTERN WILL DEAMPLIFY LATER IN THE WEEK...VERY CHILLY
AIR WILL HAVE ALREADY BEEN DISCHARGED OUT OF CANADA ACROSS THE UPPER
GREAT LAKES AND INTO THE MISSISSIPPI AND OHIO VALLEYS. FOR OUR
REGION THOUGH...WHILE WE WILL EXPERIENCE COOLER THAN NORMAL
WEATHER...THE NEWSWORTHY SHOT OF CANADIAN AIR WILL ONLY BE A
GLANCING SHOT FOR THE LOWER GREAT LAKES. THIS IS PROBABLY PUTTING
THE CART BEFORE THE HORSE THOUGH AS WE WILL HAVE TO WORK THROUGH
SOME SUMMERY CONVECTIVE WEATHER FIRST.

A DEEP UPPER LEVEL VORTEX OVER NORTHERN ONTARIO THIS EVENING WILL
SPLIT INTO TWO CENTERS BY MIDDAY MONDAY...AS ONE VIGOROUS SHORTWAVE
WITHIN THE CENTER WILL LIFT TOWARDS JAMES BAY WHILE ITS TWIN WILL
DIG SOUTHEAST ACROSS THE UPPER GREAT LAKES. THIS WILL NOT ONLY PULL
APART THE WELL DEFINED UPPER LEVEL CIRCULATION...BUT MORE
IMPORTANTLY...THE MOVEMENT OF THE SECOND SHORTWAVE WILL HELP TO PUMP
UP SOME LOW LEVEL RIDGING OVER THE LOWER LAKES. WHILE THE ENSUING
WEAK SUBSIDENCE WILL TRY TO KEEP THINGS FAIRLY SUBDUED OVER THE
FORECAST AREA ON MONDAY...THERE COULD BE JUST ENOUGH DIURNALLY BASED
INSTABILITY AND MOISTURE TO GENERATE SOME SCATTERED AFTERNOON
CONVECTION. PWAT VALUES FOR THE EASTERN PART OF THE FORECAST AREA
WILL BE IN THE VCNTY OF 1.5"...BUT WITH A WIND FIELD FAVORING A
PROGRESSIVE FLOW FOR ANY STORMS AND A RELATIVELY THIN CAPE
PROFILE...THE POTENTIAL FOR SEVERE WEATHER OR HYDRO RELATED ISSUES
WILL BE MINIMAL. AS MENTIONED...THE BULK OF MONDAY SHOULD BE RAIN
FREE. IT WILL BE SOMEWHAT LESS HUMID THAN THE DAY BEFORE AS WELL
WITH TEMPERATURES TOPPING OUT TO WITHIN A FEW DEGREES OF 80 (MID 80S
GENESEE VALLEY).

AS THE VIGOROUS SHORTWAVE PLOWS ACROSS THE UPPER GREAT LAKES MONDAY
NIGHT...THE VARIOUS GUIDANCE PACKAGES DIVERGE IN THE HANDLING OF THE
CORRESPONDING SFC FEATURES. ALL OF THE NORTH AMERICAN MODELS ARE IN
AGREEMENT THAT A COLD FRONT WILL PUSH ACROSS OUR FORECAST AREA...
WHILE THE ECMWF STANDS ALONE IN SUGGESTING THAT A SFC WAVE DEVELOPS
ALONG THE FRONT...THEREBY SLOWING ITS PROGRESSION ACROSS OUR AREA
UNTIL THE NEXT DAY (TUES). THE ECMWF IS TRENDING CLOSER TO ITS
US/CANADIAN COUNTERPARTS...BUT IS STUBBORN IN GIVING UP ON THE
NOTION OF A WAVE MOVING UP ALONG THE FRONT. GIVEN THE LACK OF RUN TO
RUN AND MODEL TO MODEL CONSISTENCY...WILL STAY CLOSE TO
CONTINUITY...WHICH WAS LARGELY BASED ON THE SLOWER ECMWF SOLUTION.
THAT BEING SAID...WILL USE CHC POPS MONDAY NIGHT WITH A TREND
TOWARDS HIGHER POPS DURING THE COURSE OF THE NIGHT AS THE
AFOREMENTIONED WAVE PUSHES ACROSS LAKE ERIE.

THE COOLER AIR WILL THEN SLOWLY WORK ITS WAY ACROSS OUR FORECAST
AREA ON TUESDAY AS THE PASSING OF THE AFOREMENTIONED WAVE WILL
FINALLY ALLOW THE COLD FRONT TO PUSH ACROSS THE REGION. EVEN THE
SLOWER ECMWF HAS THE COLD FRONT CLEARING OUR FORECAST AREA BY MID
AFTERNOON...SO DIURNALLY...THE TIMING IS NOT FAVORABLE FOR STRONG TO
SEVERE THUNDERSTORM ACTIVITY. GIVEN THE APPARENT LACK OF
INSTABILITY...WILL BACK OFF ON ANY SEVERE WEATHER WORDING THAT WAS
USED IN THE HAZARDOUS WEATHER OUTLOOK. THE UNSETTLED WEATHER AND
ASSOCIATED CLOUD COVER SHOULD HOLD MAX TEMPERATURES IN THE 70S.

FOR TUESDAY NIGHT...THE MODELS TEND TO CONVERGE ON THE SCENARIO OF
SPRAWLING HIGH PRESSURE OVER NORTHERN PLAINS EXPANDING TO THE EAST
ACROSS THE GREAT LAKES AND OHIO VALLEY WITH COOLER AND DRIER AIR
MAKING ITS WAY OVER THE LOWER GREAT LAKES. OVERNIGHT TEMPERATURES
ACROSS MUCH OF OUR REGION WILL DROP BACK INTO THE 50S...WITH 40S
ANTICIPATED OVER MUCH OF THE SRN TIER.

THE LARGE SFC HIGH WILL DRIFT EAST ACROSS THE OHIO VALLEY AND LOWER
GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT. WHILE SUBSIDENCE
ASSOCIATED WITH THIS FEATURE WILL PROVIDE THE REGION WITH GENERALLY
FAIR WEATHER...H5 TEMPS IN THE MINUS TEENS COULD OFFER ENOUGH
INSTABILITY WEDNESDAY AFTERNOON TO SUPPORT SOME ISOLATED SHOWERS.
OTHERWISE IT WILL BE QUITE COOL WITH H85 TEMPS ARND 8C LEADING TO
AFTERNOON HIGHS IN THE 60S AND LOWER 70S (10 DEG F BELOW NORMAL)
WHILE WEDNESDAY NIGHT LOWS WILL ONCE AGAIN BE IN THE 40S (SRN TIER)
AND 50S.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
THE HIGHLY AMPLIFIED PATTERN OF THE DAYS PRECEDING THIS PERIOD WILL
GIVE WAY TO A BROAD LONGWAVE TROUGH THAT WILL COVER MUCH OF THE
LOWER 48. THIS WILL INITIALLY KEEP TEMPERATURES BELOW NORMAL
THROUGHOUT THE GREAT LAKES REGION...BUT WITHOUT A DIRECT FEED OF
CANADIAN AIR TO REPLENISH THE QUICKLY MODIFYING AIRMASS...MERCURY
LEVELS WILL STEADILY CLIMB BACK TOWARDS NORMAL LEVELS.

MEANWHILE...EXPANSIVE HIGH PRESSURE WILL KEEP OUR FORECAST RAIN
FREE. THE SFC HIGH WILL BE CENTERED OVER THE OHIO VALLEY AS WE OPEN
THIS PERIOD...BUT AS WE PROGRESS INTO NEXT WEEKEND...THE HIGH WILL
DRIFT OFF THE EAST COAST. THE RETURN FLOW AROUND THIS FEATURE WILL
AID IN THE MODIFICATION OF THE ONCE COOL AIRMASS.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
THROUGH THE COURSE OF TODAY...LOW PRESSURE WILL LIFT FROM NEAR LAKE
HURON NORTHEASTWARD TOWARD JAMES BAY. IN THE PROCESS...IT WILL PIVOT
ITS ASSOCIATED WARM FRONT ACROSS THE AREA BETWEEN THIS MORNING AND
EARLY THIS AFTERNOON...BEFORE QUICKLY SWINGING ITS TRAILING COLD
FRONT INTO WESTERN PORTIONS OF THE AREA BY EARLY THIS EVENING. AS
THIS SYSTEM WORKS EASTWARD...EXPECT THE POTENTIAL FOR SHOWERS AND
EMBEDDED THUNDERSTORMS TO INCREASE FROM WEST TO EAST THIS MORNING
WITH THE APPROACH AND PASSAGE OF THE WARM FRONT. AS THESE ARRIVE...
EXPECT ROUGHLY A THREE TO FOUR HOUR-LONG WINDOW OF SHOWERS AND
POSSIBLE EMBEDDED THUNDER AT ANY GIVEN LOCATION...WITH SOME OF THESE
CAPABLE OF PRODUCING BRIEF REDUCTIONS TO MVFR/IFR IN LOCALLY HEAVY
RAINFALL GIVEN PWATS CLIMBING TO THE VICINITY OF 2 INCHES.
OTHERWISE...EXPECT GENERAL VFR CONDITIONS TO CONTINUE TO PREVAIL
THROUGH THIS MORNING...WITH SOME MVFR CIGS POSSIBLE ACROSS THE
HIGHER TERRAIN.

ONCE THIS INITIAL ROUND OF CONVECTION AND ASSOCIATED CLOUD COVER
CLEARS THE AREA...EXPECT DIURNAL HEATING TO LEAD TO AT LEAST SOME
DESTABILIZATION THIS AFTERNOON IN ADVANCE OF THE APPROACHING COLD
FRONT...WHICH SHOULD EVENTUALLY LEAD TO AT LEAST SOME SCATTERED
ADDITIONAL CONVECTION AND ATTENDANT LOCALIZED REDUCTIONS TO MVFR/IFR
DEVELOPING ALONG AND INLAND FROM A DEVELOPING LAKE BREEZE BOUNDARY
ACROSS WESTERN NEW YORK. THE BIG QUESTION AT THIS POINT REMAINS
EXACTLY HOW MUCH WE WILL DESTABILIZE...AS PLENTY OF SHEAR WILL BE IN
PLACE TO SUPPORT THE DEVELOPMENT OF STRONG TO SEVERE SURFACE-BASED
STORMS INLAND FROM THE LAKES SHOULD ENOUGH INSTABILITY ACTUALLY BE
REALIZED...WITH STRONG WINDS BEING THE PRIMARY SEVERE WEATHER THREAT
SHOULD THESE ACTUALLY OCCUR. AT THIS POINT...FEEL THAT THIS
POTENTIAL IS LESSENING GIVEN THAT WE SHOULD HAVE FAIRLY PLENTIFUL
CLOUD COVER AND SCATTERED TO NUMEROUS SHOWERS IN PLACE THROUGH AT
LEAST THE MIDDAY TO EARLY AFTERNOON HOURS...THOUGH STILL CANNOT RULE
OUT A FEW STRONGER STORMS CAPABLE OF PRODUCING STRONG WIND GUSTS.

AS WE GET INTO TONIGHT...THE TRAILING COLD FRONT WILL SLOWLY EASE
ITS WAY SOUTHEASTWARD ACROSS OUR REGION. WHILE THE LOSS OF HEATING
WILL RESULT IN NOCTURNAL STABILIZATION AND LOWERING POTENTIAL FOR
STRONG TO SEVERE STORMS...WITH A WARM AND VERY HUMID AIRMASS STILL
IN PLACE CHANCES FOR SOME ADDITIONAL SCATTERED CONVECTION WILL
LINGER UNTIL THIS BOUNDARY PASSES.

OUTLOOK...
MONDAY...MAINLY VFR WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.
TUESDAY...VFR/MVFR IN SCATTERED SHOWERS AND THUNDERSTORMS.
WEDNESDAY AND THURSDAY...MAINLY VFR.

&&

.MARINE...
A FRONTAL SYSTEM WILL CROSS THE LOWER GREAT LAKES TODAY AND TONIGHT
WHILE BRINGING SOME SHOWERS AND THUNDERSTORMS TO THE REGION. IN
ADDITION...A BRIEF PERIOD OF ADVISORY-LEVEL WINDS IS EXPECTED TODAY
IN MOST LOCATIONS AS THIS SYSTEM CROSSES THE AREA...WITH THE EASTERN
PORTIONS OF THE LAKES ALSO LIKELY SEEING WAVES BUILD TO LOW-END
ADVISORY LEVELS FOR A TIME.

LOOKING A BIT FURTHER OUT...GENERALLY UNSETTLED WEATHER WILL PERSIST
THROUGH TUESDAY...THOUGH WINDS AND WAVES SHOULD DROP BACK BELOW
ADVISORY LEVELS.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LEZ020-
         040-041.
         SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
         LOZ030.
         SMALL CRAFT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS
         EVENING FOR LOZ043>045.
         SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
         LOZ042.

&&

$$

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






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