Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 281150
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
750 AM EDT SUN JUN 28 2015

.SYNOPSIS...
A FALL LIKE STORM SYSTEM CENTERED OVER THE LOWER GREAT LAKES WILL
PRODUCE A CHILLY DAMP DAY ACROSS OUR REGION TODAY...AS MORE RAIN
WILL ACCOMPANY TEMPERATURES THAT WILL BE MORE TYPICAL OF OCTOBER.
SIGNIFICANT IMPROVEMENT CAN THEN BE EXPECTED AS WE PROGRESS
THROUGH MONDAY...AS HIGH PRESSURE WILL BRING THE RETURN TO
SUNSHINE TO THE WESTERN COUNTIES WHILE THE RAIN WILL FINALLY MOVE
OUT OF THE EASTERN LAKE ONTARIO REGION. THE BREAK IN THE UNSETTLED
WEATHER WILL BE BRIEF AS SHOWERS AND THUNDERSTORMS WILL RETURN
LATE MONDAY NIGHT AND TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
A MATURE...VERTICALLY STACKED STORM SYSTEM CENTERED OVER THE
LOWER GREAT LAKES WILL PRODUCE A DAMP DREARY DAY ACROSS ALL OF
WESTERN AND NORTH CENTRAL NEW YORK TODAY. WHILE THE AGING SYSTEM
WILL NOT HAVE THE STRONG DYNAMICS THAT IT DID DURING THE PAST 24
HOURS WHEN IT GENERATED AN INCH OR MORE OF RAIN OVER THE BULK OF
THE FORECAST AREA...A WEALTH OF ATLANTIC MOISTURE WILL STILL BE IN
PLACE.

THIS MOISTURE...FOUND WITHIN A DEEP CYCLONIC FLOW...WILL SUPPORT
FAIRLY WIDESPREAD LIGHT TO OCCASIONALLY MODERATE RAIN ACROSS OUR
AREA. GENERAL SYNOPTIC LIFT WILL BE DRIVEN BY VERY STRONG MID
LEVEL CIRCULATION...WHICH WILL BE HIGHLIGHTED BY THE 1.5 PV SFC
BEING PUSHED AS LOW AS 975MB. IN THE LOWER LEVELS...THE OCCLUSION
WILL PUSH ACROSS THE FINGER LAKES AND EASTERN LAKE ONTARIO REGION
EARLY THIS MORNING. THIS WILL PRODUCE ENHANCED AREAS OF RAIN FOR
THOSE PARTICULAR AREAS THROUGH DAYBREAK...THEN AS WORK DEEPER INTO
THE DAY...ADDITIONAL LIFT WILL BE GENERATED ACROSS A LARGE PORTION
OF THE AREA BY A NORTHERLY UPSLOPE FLOW. THIS SHOULD DIRECT THE
MOST WIDESPREAD AREAS OF RAIN ACROSS THE WESTERN COUNTIES.

RAINFALL AMOUNTS TODAY WILL RANGE A COUPLE TENTHS OF AN INCH
ACROSS THE SOUTHERN TIER...TO ROUGHLY A HALF INCH EAST OF LAKE
ONTARIO (MAINLY COURTESY OF THE EARLY MORNING RAIN).

THE RAINY WEATHER TODAY WILL BE ACCOMPANIED BY UNSEASONABLY LOW
TEMPERATURES. THE MERCURY WILL STRUGGLE TO REACH 60 IN MOST AREAS
THIS AFTERNOON...WHICH EQUATES TO READINGS THAT ARE MORE TYPICAL
OF OCTOBER. AT THESE LEVELS...RECORD LOW MAXIMUM TEMPS WILL BE
POSSIBLE. THESE INCLUDE BUFFALO (63/2004)...ROCHESTER
(61/1919)...AND WATERTOWN (64/1968). ALL OF THESE WILL HAVE THE
POTENTIAL OF BEING TIED OR BROKEN. OUR CURRENT AMPLIFIED UPPER
LEVEL FLOW OF HAVING A PRONOUNCED TROUGH IN THE EAST IS TYPICALLY
ACCOMPANIED BY A STRONG RIDGE OUT WEST. INTERESTINGLY...WHILE THIS
PATTERN IS SUPPORTING OUR VERY COOL WEATHER THIS WEEKEND...IT IS
ALSO RESPONSIBLE FOR A ONCE IN A GENERATION LATE JUNE HEAT WAVE
ACROSS THE PACIFIC NORTHWEST.

TONIGHT...THE ANOMALOUS STORM SYSTEM WILL PUSH NORTHEAST AWAY
FROM OUR FORECAST AREA. THE GENERAL SYNOPTIC LIFT WILL WEAKEN AS A
RESULT...AND WITH BACKING LOW LEVEL WINDS REMOVING THE BULK OF THE
UPSLOPE FLOW AND THE ONSET OF DRYING IN THE MID LEVELS...THE RAIN
OVER THE WESTERN COUNTIES WILL TAPER OFF AND END. THE PCPN EAST OF
LK ONTARIO WILL LINGER A BIT LONGER INTO THE DAY MONDAY.

TEMPERATURES TONIGHT WILL NOT DROP MUCH FROM THEIR DAYTIME
LEVELS...AS PLENTY OF LOW CLOUD COVER WILL ONLY ALLOW THE MERCURY
TO SETTLE INTO THE LOW TO MID 50S FOR MOST AREAS.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
ON MONDAY...THE UPPER LOW AND ATTENDANT SURFACE WAVE THAT PLAGUED
THE REGION OVER THE WEEKEND WILL CONTINUE TO LIFT NORTHEASTWARD
INTO THE CANADIAN MARITIMES...WHILE ANOTHER SHORTWAVE DROPS AROUND
THE BASE OF THE LARGER SCALE UPPER LEVEL TROUGH OVER THE GREAT
LAKES AND NORTHEAST...AND AIDS IN THE SLOW DEVELOPMENT OF A SECOND
SURFACE LOW OVER THE WESTERN GREAT LAKES/OHIO VALLEY. IN BETWEEN
THESE TWO SYSTEMS...A WEAK COMPENSATING RIDGE OF HIGH PRESSURE AND
DRIER AIR WILL BUILD ACROSS NEW YORK STATE.

CONSEQUENTLY...LINGERING SCATTERED SHOWERS FOUND FROM ROUGHLY THE
GENESEE VALLEY EASTWARD AT THE START OF THE DAY WILL CONTINUE TO
WIND DOWN...WITH THE LAST OF THESE LIKELY EXITING THE NORTH
COUNTRY BY EARLY MONDAY AFTERNOON. AT THE SAME TIME...WIDESPREAD
LOW CLOUDS AT THE START OF THE DAY WILL GIVE WAY TO SLOWLY
INCREASING AMOUNTS OF SUNSHINE BETWEEN THE LATE MORNING AND
AFTERNOON HOURS...WITH THE NORTH COUNTRY THE LAST TO SEE THIS
IMPROVEMENT. ALL OF THIS SHOULD RESULT IN A MUCH-NEEDED BREAK FROM
THIS WEEKEND`S WET AND GLOOMY CONDITIONS DURING THE AFTERNOON
HOURS...WITH THE COMBINATION OF THE INCREASING SUNSHINE AND SOME
MODEST WARMING ALOFT ALLOWING HIGH TEMPERATURES TO RECOVER BACK
INTO THE LOWER TO MID 70S SOUTH OF LAKE ONTARIO...AND TO THE MID
AND UPPER 60S FURTHER EAST.

THIS RELATIVE BREAK IN THE WEATHER WILL BE SHORT-LIVED
HOWEVER...AS THE AFOREMENTIONED SHORTWAVE TROUGH AND ATTENDANT
SECOND SURFACE LOW WILL LIFT NORTHEAST INTO SOUTHERN ONTARIO
MONDAY NIGHT...WHILE SPREADING INCREASING AMOUNTS OF MOISTURE AND
WARM ADVECTIVE LIFT BACK INTO OUR REGION. THIS WILL RESULT IN
CLOUD COVER ONCE AGAIN INCREASING FROM SOUTHWEST TO NORTHEAST OVER
TIME...ALONG WITH GRADUALLY INCREASING PROBABILITIES FOR SHOWERS
FROM THE FINGER LAKES WESTWARD. GIVEN THE GENERAL WARM AIR
ADVECTION REGIME AND INCREASING CLOUD COVER...LOWS MONDAY NIGHT
WILL BE MILDER THAN THOSE OF SUNDAY NIGHT...WITH NIGHTTIME
MINIMUMS RANGING FROM THE MID 50S ACROSS THE NORTH COUNTRY TO THE
LOWER 60S ACROSS THE LAKE PLAINS OF WESTERN NEW YORK.

THE MOST ACTIVE WEATHER OF THIS PERIOD WILL THEN FOLLOW FOR
TUESDAY AND TUESDAY NIGHT...WHEN THE SURFACE LOW WILL TRACK
DIRECTLY ACROSS THE LOWER GREAT LAKES AND INTO THE SAINT LAWRENCE
VALLEY. IN THE PROCESS...THIS FEATURE WILL FIRST PUSH ITS
ATTENDANT WARM FRONT ACROSS OUR REGION TUESDAY...FOLLOWED BY A
PRE-COLD-FRONTAL TROUGH LATER TUESDAY AFTERNOON AND EVENING. WITH
PLENTY OF MOISTURE /PWATS OF 1.5 INCHES/ AVAILABLE IN THE PRESENCE
OF SUFFICIENT LIFT AND INCREASING AMOUNTS OF INSTABILITY...HAVE
CONTINUED TO INDICATE A HIGH LIKELIHOOD OF SHOWERS AS WELL AS THE
POTENTIAL FOR SOME THUNDERSTORMS FROM TUESDAY INTO TUESDAY NIGHT.

SPEAKING OF THUNDERSTORMS...IT IS BEGINNING TO APPEAR AS IF THERE
MAY BE AT LEAST SOME LIMITED POTENTIAL FOR SOME STRONGER TO EVEN
SEVERE STORMS BETWEEN TUESDAY AFTERNOON AND EVENING...IN
CONJUNCTION WITH THE PASSAGE OF THE PREFRONTAL TROUGH AND PEAK
AFTERNOON HEATING. COMPARED TO YESTERDAY...THE 00Z/28 GUIDANCE
SUITE HAS TRENDED MORE BULLISH ON THE AMOUNT OF AVAILABLE
INSTABILITY...WITH THE NAM/GFS IN PARTICULAR NOW SUGGESTING THAT
AS MUCH AS 1000-1800 J/KG OF SBCAPE COULD DEVELOP ACROSS MUCH OF
THE REGION SOUTH OF LAKE ONTARIO... ALONG WITH LIFTED INDICES
FALLING TO BETWEEN -4 AND -8 CELSIUS. AT THE SAME TIME...THE
PREVAILING LARGER-SCALE UPPER LEVEL TROUGH ACROSS OUR REGION WILL
PROVIDE RELATIVELY COOL TEMPERATURES ALOFT ALONG WITH A GENERAL
35-45 KT SOUTHWESTERLY MID LEVEL FLOW...LEADING TO 0-6 KM BULK
SHEAR VALUES OF 35-45 KNOTS. COUPLING ALL OF THESE FACTORS
TOGETHER...IT APPEARS THAT THE POTENTIAL EXISTS FOR AT LEAST SOME
ISOLATED STRONGER TO POSSIBLY SEVERE STORMS TUESDAY AFTERNOON AND
EVENING WITH GUSTY WINDS AND HAIL BEING THE PRIMARY THREATS...
WHICH JUST HAPPENS TO COINCIDE QUITE NICELY WITH THE MARGINAL RISK
FOR OUR AREA PORTRAYED IN THE NEW SPC DAY 3 CONVECTIVE OUTLOOK.
WHILE WE WILL NOT HIGHLIGHT THIS POSSIBILITY IN THE HWO JUST YET
GIVEN LINGERING UNCERTAINTY WITH RESPECT TO THE AMOUNT OF
AVAILABLE INSTABILITY AND THE CURRENT MARGINAL NATURE OF THE
SEVERE THREAT... THIS WILL NEED TO BE WATCHED OVER THE NEXT COUPLE
OF DAYS.

BY WEDNESDAY MORNING...THE BROAD SURFACE LOW WILL LIKELY BE
CENTERED SOMEWHERE OVER EITHER SOUTHERN QUEBEC OR THE SAINT
LAWRENCE VALLEY... WITH ITS TRAILING COLD FRONT EXTENDING
SOUTHWESTWARD ACROSS THE LOWER GREAT LAKES. THROUGH THE COURSE OF
THE DAY...THE LOW WILL CONTINUE TO LIFT NORTHEASTWARD TOWARD
LABRADOR...WHILE SLOWLY PUSHING ITS TRAILING COLD FRONT ACROSS
WESTERN AND NORTH CENTRAL NEW YORK. COUPLED WITH A STILL-MOIST
AIRMASS AND RENEWED DAYTIME HEATING...THE FRONTAL PASSAGE WILL
PROBABLY LEAD TO SOME ADDITIONAL SCATTERED CONVECTION DEVELOPING
DURING THE DAY ON WEDNESDAY...BEFORE HIGH PRESSURE AND DRIER AIR
BUILDING INTO THE REGION WEDNESDAY NIGHT PROVIDES A RETURN TO
MAINLY DRY AND QUIET WEATHER TO CLOSE OUT THE SHORT TERM PERIOD.

WITH RESPECT TO TEMPERATURES TUESDAY AND WEDNESDAY...THESE SHOULD
CONTINUE TO AVERAGE OUT A LITTLE BELOW EARLY SUMMER NORMALS GIVEN
THE CONTINUED PRESENCE OF BROAD UPPER LEVEL TROUGHING ACROSS OUR
REGION. EXPECT DAYTIME HIGHS TO RANGE IN THE MID TO UPPER 70S
TUESDAY AND THE LOWER TO MID 70S WEDNESDAY...WHILE NIGHTTIME LOWS
WILL BE IN THE UPPER 50S TO LOWER 60S TUESDAY NIGHT...BEFORE
FALLING BACK TO THE LOWER TO MID 50S WEDNESDAY NIGHT.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
IT STILL APPEARS THAT THIS PERIOD SHOULD START OFF WITH A
GENERALLY DRY AND UNEVENTFUL DAY ON THURSDAY WITH HIGH PRESSURE
AND DRIER AIR THE DOMINANT WEATHER FEATURE AT THE LOWER
LEVELS...THOUGH IT IS WORTH NOTING THAT BOTH THE 00Z GFS/GEM ARE
NOW SPITTING OUT SOME ADDITIONAL PRECIP DUE TO THE PASSAGE OF YET
ANOTHER SHORTWAVE. WITH BOTH OF THESE MODELS MUCH STRONGER WITH
THIS FEATURE AND APPEARING OVERDONE COMPARED TO SOME OF THE OTHER
GUIDANCE...HAVE ELECTED TO STICK WITH OUR EXISTING MORE OPTIMISTIC
CONTINUITY AND A WPC/ECMWF- FAVORED DEPICTION OF A DRY DAY...ALONG
WITH BELOW NORMAL HIGHS IN THE LOWER HALF OF THE 70S.

AFTER THAT...THINGS BECOME MORE UNCERTAIN AS WE HEAD INTO THE
LONG INDEPENDENCE DAY HOLIDAY WEEKEND...AS THE MEDIUM RANGE
GUIDANCE CONTINUES TO EXHIBIT NOTABLE MODEL-TO-MODEL AND RUN-TO-
RUN VARIABILITIES IN THE TIMING AND STRENGTH OF THE NEXT LOW
PRESSURE SYSTEM LATE IN THE WEEK...AS IS TYPICAL THIS FAR OUT IN
ADVANCE. GIVEN THESE...HAVE ELECTED TO LEAN CLOSER TO WPC GUIDANCE
AND THE GENERALLY MORE CONSISTENT ECMWF FOR THE LATTER PORTION OF
THIS PERIOD...WHICH WOULD SUGGEST A GENERAL LOWER-END CHANCE FOR
SHOWERS AND STORMS BOTH DAYS...ALONG WITH CONTINUED SLIGHTLY BELOW
NORMAL TEMPERATURES.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
A STACKED...FALL LIKE STORM SYSTEM OVER THE LOWER GREAT LAKES
WILL RESULT IN WIDESPREAD IFR CIGS THROUGH TONIGHT. THE LOW CIGS
WILL BE ACCOMPANIED BY MORE RAIN AND DRIZZLE...ALTHOUGH THE
INTENSITY OF THE RAIN WILL NOT BE AS HEAVY AS IT WAS DURING
THE DAY ON SATURDAY.

OUTLOOK...

MONDAY...MAINLY VFR. A CHANCE OF SHOWERS EAST OF LAKE ONT.
MONDAY NIGHT AND TUESDAY...MAINLY VFR...BUT WITH SHOWERS AND
THUNDERSTORMS BECOMING LIKELY.
WEDNESDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
THURSDAY...VFR.

&&

.MARINE...
A MATURE STORM SYSTEM CENTERED OVER THE LOWER GREAT LAKES THIS
MORNING WILL GRADUALLY MOVE EAST TO THE SAINT LAWRENCE VALLEY LATE
TODAY AND TONIGHT. THIS WILL ENCOURAGE WINDS TO FURTHER SUBSIDE
ACROSS THE LOWER GREAT LAKES...ALLOWING SMALL CRAFT ADVISORIES ON
THE WESTERN HALF OF LAKE ONTARIO TO EXPIRE BY MIDDAY. DESPITE THE
LOWERING OF WINDS AND WAVES THOUGH... FAIRLY WIDESPREAD AREAS OF
RAIN WILL PERSIST INTO THIS EVENING.

HIGH PRESSURE WILL NOSE NORTH ACROSS THE LOWER GREAT LAKES LATER
TONIGHT AND MONDAY. THIS WILL SUPPORT LIGHT WINDS AND NEGLIGIBLE
WAVES.

THE RETURN TO FAIR WEATHER WILL BE A BRIEF ONE...AS CONDITIONS
WILL DETERIORATE MONDAY NIGHT AND TUESDAY. WHILE WINDS WILL
FRESHEN ACROSS THE LOWER GREAT LAKES AND SAINT LAWRENCE
VALLEY...THERE WILL ONLY BE A LOW CHC FOR SMALL CRAFT ADVISORY
CONDITIONS. OF MORE CONCERN WILL BE THE RETURN OF UNSETTLED
WEATHER WITH SHOWERS AND THUNDERSTORMS ONCE AGAIN BECOMING LIKELY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR LOZ043.
         SMALL CRAFT ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR
         LOZ042.

&&

$$

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



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