Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 291731
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
131 PM EDT WED OCT 29 2014

.SYNOPSIS...
MUCH COOLER AIR WILL SWEEP BACK INTO THE REGION TODAY WITH A FEW
LAKE EFFECT RAIN SHOWERS EAST OF LAKE ERIE...AND THEN EAST OF LAKE
ONTARIO THIS EVENING. PROGRESSIVELY COLDER WEATHER WILL THEN
CONTINUE FOR THE REMAINDER OF THE WEEK. ANOTHER LOW PRESSURE SYSTEM
IS EXPECTED TO CROSS THE AREA FRIDAY AND SATURDAY WITH RAIN
POTENTIALLY TRANSITIONING INTO THE FIRST SNOWFLAKES OF THE SEASON BY
SATURDAY MORNING.

&&

.NEAR TERM /THROUGH TONIGHT/...
COLDER AIR WILL CONTINUE TO BUILD ACROSS OUR REGION THROUGH THE TIME
PERIOD WITH TEMPERATURES ALOFT AT 850 HPA DROPPING FROM AROUND 0 TO
+6C (WEST TO EAST) TO -4 TO -2C BY THE CLOSE OF TONIGHT. THIS COLD
AIR ADVECTION WILL BEGIN TO CREATE LAKE INSTABILITY THIS MORNING. AN
ALIGNED SOUTHWEST WIND OVER THE UNSTABLE LAKE SURFACE WILL BEGIN TO
DEVELOP LAKE EFFECT RAIN SHOWERS THROUGH THE MORNING HOURS...WITH
ADDITIONAL LIFT FROM AN NEARING UPPER LEVEL SHORTWAVE. WHILE OVERALL
LAKE INDUCED EQUILIBRIUM LEVELS AND CAPE ARE NOT OVERLY IMPRESSIVE
(AROUND 9K FEET AND 250-500 J/KG) THEY SHOULD REMAIN ADEQUATE TO
PRODUCE NARROW BANDS OF LAKE EFFECT RAIN WITHIN AN ALIGNED SOUTHWEST
FLOW OFF LAKE ERIE TODAY...AND STARTING LATER IN THE DAY OFF LAKE
ONTARIO. AS WINDS BACK SLIGHTLY AHEAD OF THE UPPER LEVEL
SHORTWAVE...WILL CONTINUE WITH A NARROW RIBBON OF LIKELY POPS JUST
TO THE SOUTH OF BUFFALO AND BATAVIA OFF LAKE ERIE...AND LATER IN THE
DAY/EVENING TOWARDS THE TUG HILL REGION. THE RELATIVELY STRONGER
SOUTHWEST FLOW...SYNOPTIC SCALE MOISTURE AND INSTABILITY SUGGEST
THESE LAKE EFFECT RAIN SHOWERS WILL EXTEND FAR INLAND INTO THE
FINGER LAKES AND POSSIBLY EVEN CENTRAL NEW YORK.

AS THE UPPER LEVEL SHORTWAVE DROPS SOUTHEASTWARD THIS EVENING AND
OVERNIGHT WINDS WILL VEER AROUND TO WEST-NORTHWEST. THIS WILL ACT TO
PUSH THE LAKE EFFECT RAIN BANDS SOUTHWARD. THIS WOULD PLACE THE
BANDS ACROSS SKI COUNTRY/WESTERN SOUTHERN TIER OFF LAKE ERIE...AND
DROPPING FROM THE CENTRAL TUG HILL REGION DOWN TO AREAS SOUTHEAST OF
LAKE ONTARIO.

THROUGH THE OVERNIGHT THESE MODEST LAKE PARAMETERS BEGIN TO
WEAKEN...AND EXPECT A SIMILAR RESPONSE TO THE BANDS OF LAKE EFFECT
RAIN. THIS...COMBINED WITH NORTHWEST WINDS TEND TO FAVOR LIGHTER
MULTI BANDED LAKE BAND STRUCTURES WILL SUPPORT JUST LOW CHANCE POPS
TO CLOSE OUT THE PERIOD.

MOSTLY CLOUDY SKIES THIS MORNING WILL ONLY PARTIALLY CLEAR
TODAY...AND THIS CLEARING WILL BE AWAY FROM LAKE EFFECT BANDS.
TONIGHT WITH ABUNDANT LOW LEVEL MOISTURE AND COLD...NORTHWEST FLOW
BEHIND THE UPPER LEVEL SHORTWAVE EXPECT MOSTLY CLOUDY SKIES THROUGH
THE NIGHT.

TEMPERATURES TODAY WILL BE MUCH COLDER...WITH HIGHS RANGING THROUGH
THE 50S. WARMEST SPOTS WILL BE ACROSS EASTERN AREAS WHERE THE COLD
AIR IS JUST NOW BEGINNING TO BUILD IN BEHIND THE COLD FRONT. LOWS
TONIGHT WILL DROP OFF TO THE 30S...WITH A FEW AREAS SOUTHEAST OF
LAKE ONTARIO AND WITH A WEST-NORTHWEST WIND FLOW ACROSS THE STILL
WARM LAKE ONTARIO PROVIDING FOR LOWS REMAINING IN THE LOWER 40S.

&&

.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
NOT ONLY WILL TEMPERATURES AVERAGE BELOW NORMAL DURING THIS
PERIOD...BUT THEY WILL TREND LOWER AND LOWER RIGHT INTO THE WEEKEND.
THERE ARE SOME AREAS THAT WILL EVEN GET THEIR FIRST CHANCE OF
MEASURABLE SNOW...BUT THAT IS MUCH LESS CERTAIN THAN THE DIRECTION
OF OUR TEMPERATURES.

A SAPLESS LOOKING SHORTWAVE OVER THE NORTHWEST TERRITORIES THIS
MORNING WILL GATHER SOME VIGOR AND MOMENTUM AS IT WILL DIG SOUTH
INTO THE BACKSIDE SIDE OF AN ALREADY ESTABLISHED LONGWAVE TROUGH
OVER THE EASTERN HALF OF NORTH AMERICA. THIS PROCESS WILL BE AIDED
BY A BURGEONING RIDGE OVER THE INTERMOUNTAIN WEST...ONE THAT WILL
COME AS A RESULT OF ANOTHER DIGGING LONGWAVE TROUGH OFF THE WEST
COAST. THE RESULTING HIGHLY AMPLIFIED TWO WAVE PATTERN OVER NORTH
AMERICA WILL SEND A SURGE OF COLD AIR SOUTHWARDS TOWARDS THE LOWER
GREAT LAKES...BUT WITH SOME OF THE COLDEST H85 TEMPS OF JUST -10 TO
-15C IN THE VCNTY OF HUDSON BAY...THERE REALLY IS NOT ANY TRUE COLD
AIR TO SPEAK OF. WITHOUT ANY SNOWCOVER THIS AIRMASS WILL UNDOUBTEDLY
MODIFY AS IT SETTLES TO THE SOUTH...AND THE BULK OF IT WILL PASS BY
ACROSS QUEBEC ANYWAY.

GETTING BACK TO THE STRONG SHORTWAVE THAT WILL ULTIMATELY DRIVE THE
OVERALL PATTERN OVER OUR REGION...THE MID LEVEL DISTURBANCE WILL
INTENSIFY TO THE POINT WHERE IT WILL LOWER THE 1.5PV SFC TO ARND
800MB BY THE TIME IT MAKES ITS WAY TO THE MID-WEST AND OHIO VALLEY
ON FRIDAY. WITH THE HELP OF THE WARMER WATERS OF THE UPPER GREAT
LAKES...A WEAK SFC REFLECTION WILL DEVELOP IN THE VCNTY OF THE
MICHIGAN STRAITS. THE NEARLY OPEN SFC WAVE WILL THEN TAKE AN UNUSUAL
PATH TO THE SOUTHEAST ACROSS LAKE ERIE...AFTER WHICH TIME IT WILL
TRANSFER WHAT LITTLE ENERGY IT HAS TO THE COAST WHERE CYCLOGENESIS
FROM THE DIGGING SHORTWAVE WILL ALREADY BE UNDERWAY.

THE FIRST REAL NOR`EASTER OF THE SEASON IS THEN EXPECTED TO DEVELOP
FROM THIS WHOLE SCENARIO...ALTHOUGH THE VARIOUS GUIDANCE PACKAGES
CONTINUE TO DIFFER ON THE INTENSITY AND PLACEMENT OF THE ENSUING
BOMBOGENESIS. WHILE THIS WILL PLAY A HUGE ROLE FOR THOSE ALONG THE
COAST...THE OVERALL IMPACTS FROM THIS NEWSWORTHY STORM WILL BE
MINIMAL ON OUR FORECAST AREA. THIS WILL ONLY PLAY INTO THE AMOUNT OF
HOW MUCH WIND OUR EASTERN ZONES EXPERIENCE AND THE EXTENT OF
NORTHERLY FLOW LAKE EFFECT ACROSS THE FINGER LAKES REGION.

ON THURSDAY...WEAK LOW LEVEL RIDGING OVER THE OHIO VALLEY WILL
EXTENT NORTHWARDS ACROSS THE LOWER GREAT LAKES. A GENERAL CYCLONIC
FLOW ALOFT WILL HELP TO KEEP SKIES AT PARTLY...IF NOT MOSTLY CLOUDY
WHILE LIGHT NUISANCE LAKE EFFECT RAIN SHOWERS WILL BE FOUND EAST OF
LK ONTARIO. A SERIOUS LACK OF ANY MID LEVEL SYNOPTIC MOISTURE AND A
PALTRY CAP OF JUST 6K FT WILL INHIBIT ANY REAL NOTABLE LAKE
RESPONSE. TEMPERATURES WILL PEAK WITHIN A FEW DEGREES OF 50.

THURSDAY NIGHT...THE AFOREMENTIONED STRONG SHORTWAVE WILL PLOW
ACROSS THE UPPER GREAT LAKES WHILE MOISTURE AHEAD OF A WEAK SFC LOW
WILL GRADUALLY INCREASE OVER OUR REGION. WHILE THE VAST MAJORITY OF
THE NIGHT WILL BE PCPN FREE...SOME SHOWERS COULD BREAK OUT CLOSE TO
THE LAKES TOWARDS MORNING.

THE SFC WAVE WILL TRACK FROM LAKE HURON TO LAKE ERIE DURING THE
COURSE OF THE DAY FRIDAY...WHILE IN THE UPPER LEVELS...A 110KT H25
WILL STREAK SOUTH ACROSS THE MISSISSIPPI VALLEY. THE AREA OF LIFT
PROVIDED UNDER THE LEFT FRONT EXIT REGION OF THIS JET WILL SKIRT THE
WESTERN COUNTIES...WHERE IT JUST HAPPENS THAT THE GREATEST HGT FALLS
WILL ALSO BE IN PLACE. THIS SHOULD ALLOW THE SHOWERS TO BECOME MORE
NUMEROUS OVER THE FAR WESTERN COUNTIES...WITH MUCH LESS ACTIVITY
FOUND EAST OF THE GENESEE VALLEY. EVEN WHERE THE SHOWERS WILL BE
MOST COMMON...RAINFALL AMOUNTS WILL ONLY RANGE FROM A TENTH OR TWO.
TEMPERATURES FRIDAY WILL NOT MAKE IT OUT OF THE 40S.

ON FRIDAY NIGHT...WHAT LITTLE ENERGY IS ASSOCIATED WITH THE EXITING
SFC WAVE WILL BE HANDED OFF TO THE COAST WHERE A LARGE STORM SYSTEM
WILL BE IN THE MAKING. A WEALTH OF LOW LEVEL MOISTURE WILL BE LEFT
BEHIND ACROSS OUR FORECAST AREA...PARTLY BEING FED BY A DEEPENING
EASTERLY FLOW FROM THE ATLANTIC. THE SEMBLANCE OF A DEFORMATION ZONE
IS EXPECTED TO SETTLE SOUTH ACROSS THE WESTERN COUNTIES...SO WILL
LEAVE LIKELY POPS IN PLACE. IN REGARDS TO P-TYPE...TEMPERATURES AT
CLOUD LEVEL WILL BE LOW ENOUGH TO SUPPORT PLENTY OF DENDRITIC SNOW
GROWTH...BUT THE LOWEST PORTION OF THE BOUNDARY LAYER JUST LOOKS TOO
`WARM` TO SUPPORT MORE THAN WET FLAKES ACROSS HIGHER ELEVATIONS.
YES...THERE COULD BE SOME DYNAMIC COOLING TO HELP WITH KEEPING THE
PCPN IN THE FORM OF SNOW...BUT THE NEARLY SATURATED ATLANTIC AIRMASS
WILL NOT OFFER A LOT OF `ROOM` FOR EVAPORATIVE COOLING...AND AM NOT
EXPECTING THE PCPN TO BE HEAVY ENOUGH TO ALLOW FOR SIGNIFICANT
COOLING DUE TO MELTING. THIS WILL BE A CLOSE CALL THOUGH...SO AM NOT
RULING OUT MINOR SLUSHY ACCUMS ACROSS THE HIGHER TERRAIN.

ON SATURDAY...THE BIG STORY WILL BE A THE DEEPENING NOR`EASTER OFF
THE EAST COAST. THIS FEATURE WILL COMBINE WITH AN EXPANSIVE AREA OF
HIGH PRESSURE OVER THE UPPER GREAT LAKES TO PRODUCE A CHILLY
NORTHERLY FLOW ACROSS OUR FORECAST AREA. ABUNDANT SYNOPTIC MOISTURE
OVER OUR REGION WILL BECOME FURTHER ENHANCED BY THE CHILLY FLOW
ACROSS LAKE ONTARIO...WHICH WILL THEN BE OROGRAPHICALLY LIFTED OVER
THE WESTERN COUNTIES. SINCE H85 TEMPS WILL BE IN THE VCNTY OF -6C...
THE BULK OF THE PCPN SHOULD FALL AS SNOW SHOWERS...BUT TEMPS IN THE
LOWEST COUPLE THOUSAND FEET COULD GET HIGH ENOUGH TO CHANGE SOME OF
THE PCPN BACK TO LIQUID DURING THE MIDDAY AND AFTERNOON. THIS WOULD
BE THE MOST LIKELY BE THE PERIOD WHERE ANY WIDESPREAD SNOW
ACCUMULATIONS COULD TAKE PLACE...AND THIS WOULD MAINLY BE ON GRASSY
AREAS...CARS AND ELEVATED SURFACES. HIGH TEMPERATURES SATURDAY WILL
RANGE FROM THE UPPER 30S (ELEVATIONS) TO LOWER 40S (LK PLAINS).

AS RIDGING SLOWLY PUSHES EAST ACROSS THE GREAT LAKES AND THE
NOR`EASTER CHUGS FURTHER UP THE NEW ENGLAND COAST SATURDAY NIGHT...
THE BULK OF THE SYNOPTIC MOISTURE SHOULD BE STRIPPED AWAY FROM OUR
REGION. WE WILL STILL HAVE A LAKE ENHANCED UPSLOPE FLOW IN PLACE
THOUGH...SO SNOW SHOWERS ARE STILL EXPECTED...ALBEIT IT TOO A LESSER
EXTENT.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE WAVY PATTERN FOUND OVER NORTH AMERICA DURING THE WEEKEND WILL
DE-AMPLIFY EARLY NEXT WEEK...AND THIS WILL ALLOW PACIFIC MODIFIED
AIR TO FLOOD THE COUNTRY. OUR TEMPERATURES WILL STEADILY CLIMB AS A
RESULT...WITH MERCURY READINGS RETURNING TO ABOVE NORMAL LEVELS BY
TUESDAY AFTERNOON.

THERE IS STRONG CONSENSUS BETWEEN THE MEDIUM RANGE ENSEMBLES...AND
THUS RELATIVELY HIGH CONFIDENCE...THAT THE WARMER THAN NORMAL
CONDITIONS WILL THEN PERSIST THROUGH MUCH...IF NOT ALL OF THE
REMAINDER OF THE WEEK. FOR WHAT ITS WORTH...THIS PACIFIC WARMTH IN
THE LONGER RANGE OUTLOOK IS SUPPORTED BY BOTH THE 6 TO 10...AND 8 TO
14 DAY TEMP OUTLOOKS FROM THE CLIMATE PREDICTION CENTER.

IN TERMS OF PCPN...STRONG RIDGING OVER THE MISSISSIPPI VALLEY ON
SUNDAY WILL PUSH EAST ACROSS THE GREAT LAKES SUNDAY NIGHT THROUGH
MONDAY. WHILE A CHILLY NORTHERLY FLOW COULD STILL PRODUCE SOME
FLURRIES OR SPRINKLES OVER PARTS OF THE REGION ON SUNDAY...THE RIDGE
WILL PROMOTE DRY FAIR WEATHER SUNDAY AFTERNOON THROUGH AT LEAST
MONDAY. A PACIFIC BASED COOL FRONT WILL THEN OFFER THE CHANCE FOR
SOME RAIN SHOWERS FOR TUESDAY.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A COOL WEST SOUTHWEST FLOW WILL DEVELOP A BAND OF LAKE EFFECT
RAIN SHOWERS OFF LAKE ERIE THROUGH TONIGHT. THIS ACTIVITY MAY
BRUSH BY THE KBUF AIRFIELD...FOR WHICH A VCSH WILL BE IN PLACE FOR
THIS AFTERNOON. BEHIND A SHORTWAVE WINDS WILL VEER AROUND TO WEST-
NORTHWEST WITH THE LAKE EFFECT RAIN BAND OFF LAKE ERIE DROPPING
SOUTHWARD...AND TOWARDS THE SOUTHERN TIER.

OFF LAKE ONTARIO EXPECT A BAND OF RAIN SHOWERS TO FORM...BUT
LIKELY NOT UNTIL TOWARD THIS EVENING AS SOUTHWESTERLY WINDS ALIGN.
THIS BAND LIKEWISE WILL DROP SOUTHWARD ACROSS AREAS EAST OF LAKE
ONTARIO THROUGH THE OVERNIGHT TIME PERIOD.

CIGS WILL LARGELY BE VFR THROUGH THE TIME PERIOD...THOUGH SOME
INSTANCES OF MVFR WILL BE LIKELY...ESPECIALLY WITHIN ANY LAKE EFFECT
RAIN BANDS. THESE BANDS OF LAKE EFFECT RAIN WILL DIMINISH IN
INTENSITY THROUGH THE OVERNIGHT AS INVERSION HEIGHTS DROP...AND LOW
LEVEL CONVERGENCE WEAKENS.

BY LATE TONIGHT SOME IFR CIGS ARE POSSIBLE ACROSS THE SOUTHERN TIER
AS LOW LEVEL SYNOPTIC MOISTURE...COMBINED WITH MOISTURE FROM LAKE
EFFECT RAIN FORM LOWER CEILINGS ACROSS THE HIGHER TERRAIN OF THE
SOUTHERN TIER. CONFIDENCE IN THIS OCCURRING IS LOW.

OUTLOOK...
THURSDAY...MAINLY VFR...EXCEPT MVFR WITH A CHANCE OF SHOWERS
DOWNWIND OF THE LAKES.
FRIDAY...VFR/MVFR WITH RAIN SHOWERS BECOMING LIKELY FRIDAY...WITH
FURTHER DETERIORATION TO IFR/MVFR AS THE PRECIPITATION CHANGES OVER
TO SNOW SHOWERS FRIDAY NIGHT.
SATURDAY...MVFR/IFR WITH SCATTERED TO NUMEROUS SNOW SHOWERS.
SUNDAY AND MONDAY...MAINLY VFR.

&&

.MARINE...
DEEP LOW PRESSURE NEAR JAMES BAY WILL ADVANCE ACROSS NORTHERN QUEBEC
PROVINCE THROUGH THURSDAY. BEHIND THIS LOW...WESTERLY WINDS WILL
RUSH OVER THE LOWER GREAT LAKES TODAY...MAINTAINING 4+ FOOT WAVE
HEIGHTS ON LAKE ERIE...WHILE WAVES WILL INCREASE THROUGH THE DAY ON
LAKE ONTARIO. THESE WINDS...VEERING TO NORTHWESTERLY THROUGH
TOMORROW WILL PRODUCE AN EXTENDED PERIOD OF ADVISORY-LEVEL WINDS AND
WAVES ACROSS THE LOWER LAKES...FOR WHICH SMALL CRAFT ADVISORIES WILL
REMAIN IN EFFECT.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT THURSDAY FOR LEZ040-041.
         SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
         LEZ020.
         SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR
         LOZ043-044.
         SMALL CRAFT ADVISORY UNTIL 5 AM EDT THURSDAY FOR LOZ042.
         SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR LOZ045.

&&

$$

SYNOPSIS...THOMAS
NEAR TERM...THOMAS/TMA
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...TMA
MARINE...THOMAS/TMA




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