244
FXUS61 KBUF 161944
AFDBUF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
344 PM EDT WED OCT 16 2013
.SYNOPSIS...
SHOWERS AND SCATTERED THUNDERSTORMS ARE EXPECTED LATE THIS
AFTERNOON THROUGH THE FIRST HALF OF TONIGHT AS A COLD FRONT PUSHES
ACROSS WESTERN AND NORTH CENTRAL NEW YORK. AN UPPER TROUGH ACROSS
THE CENTRAL PLAINS THIS EVENING WILL MOVE OVER NEW YORK ON THURSDAY
EVENING WITH ANOTHER ROUND OF RAIN SHOWERS AND STEADIER RAIN.
NOTICEABLY COOLER AIR WILL SPREAD ACROSS THE REGION AND PERSIST
THROUGH THE NEXT SEVERAL DAYS.
&&
.NEAR TERM /THROUGH THURSDAY/...
A PREFRONTAL BAND OF CONVECTION WILL SWEEP EASTWARD ACROSS CENTRAL
AND EASTERN NEW YORK ALONG A LOW LEVEL JET...EXITING THE EASTERN
FRONTIER OF THE FORECAST AREA BY THE END OF THE WORK DAY. THE COLD
FRONT WILL FOLLOW AND CROSS THE FORECAST AREA LATE THIS AFTERNOON
AND EVENING WITH ADDITIONAL SHOWERS AND SCATTERED THUNDERSTORMS...
SOME OF WHICH MAY PRODUCE BRIEF DOWNPOURS.
850MB TEMPS WILL FALL TO AROUND +4C BY THURSDAY MORNING WHICH IS
MARGINALLY COLD ENOUGH FOR A LAKE EFFECT RESPONSE ALONG THE EASTERN
SHORES OF LAKES ERIE AND ONTARIO. WILL CARRY CHANCE POPS ALONG THE
LAKESHORE COUNTIES FOR QPFS GENERALLY LESS THAN TENTH OF AN INCH.
EXPECT A MINOR COOL DOWN FOLLOWING THE COLD FRONT...THEN ANOTHER
UPPER TROUGH CROSSES THE REGION LATE THURSDAY AFTERNOON AND EVENING
WITH SHOWERS AND A MORE STEADY RAIN.
TEMPERATURES WILL FALL TO THE UPPER 40S TO LOWER 50S OVERNIGHT WITH
PARTIAL CLEARING. VALLEY FOG MAY AGAIN FORM ACROSS THE SOUTHERN
TIER...OUTSIDE OF AREAS OF LAKE EFFECT CLOUDINESS.
HIGH TEMPS ON THURSDAY WILL BE LIMITED TO THE MID 50S TO LOWER 60S
WITH A COOL TEMPERATURES ADVECTIVE PATTERN.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
A BROAD...FULL LATITUDE TROUGH WILL DOMINATE MUCH OF NORTH AMERICA
DURING THIS PERIOD...WHILE A PAIR OF ROBUST SHORTWAVES WILL KEEP A
FAIR AMOUNT OF UNSETTLED WEATHER ACROSS OUR IMMEDIATE FORECAST AREA.
THE HIGH AMPLITUDE FLOW WILL CERTAINLY BE MORE FALL LIKE THAN WHAT
WE HAVE EXPERIENCED THE PAST SEVERAL WEEKS WITH TEMPERATURES FINALLY
AVERAGING WITHIN A FEW DEGREES OF SEASONAL NORMALS. THE DETAILS...
A POTENT SHORTWAVE THAT GENERATED SOME SNOW ACROSS PARTS OF NEW
MEXICO AND TEXAS THIS MORNING WILL LIFT OUT ACROSS THE CENTRAL
PLAINS TONIGHT AND THE MID WESTERN STATES ON THURSDAY MORNING BEFORE
CROSSING OUR REGION THURSDAY NIGHT. THIS FEATURE WILL GENERATE A
QUARTER TO A HALF INCH OF RAIN ACROSS WESTERN AND NORTH CENTRAL NEW
YORK...WITH MARGINALLY CHILLY AIR SUPPORTING A LITTLE LAKE
ENHANCEMENT EAST OF BOTH LAKES. HAVE RAISED LIKELY TO CAT POPS TO
100 REGIONWIDE. THE BULK OF THE RAIN WILL COME LATE THURSDAY
AFTERNOON THROUGH THE FIRST HALF OF THURSDAY NIGHT.
LOW LEVEL RIDGING AND A WEALTH OF MID LEVEL DRYING WILL WORK ACROSS
OUR REGION IN THE WAKE OF THE EXITING SHORTWAVE ON FRIDAY SO THAT
THE BULK OF ANY LEFTOVER SHOWERS SHOULD END BY MID MORNING. THE
EXCEPTION WILL EAST OF BOTH LAKES WHERE SOME MINOR LAKE SHOWERS WILL
TAKE A FEW MORE HOURS TO PETER OUT. THE DAY SHOULD END UP BEING
PARTLY SUNNY FOR MOST SITES...WITH TEMPERATURES PEAKING BETWEEN 55
AND 60.
AN INNOCENT LOOKING SHORTWAVE CROSSING THE WEST COAST RIDGE...
'VISIBLE' ONLY AS AN OBSCURE PATCH OF WV BRIGHTNESS OVER THE
YUKON...WILL EVENTUALLY SPIN UP INTO AN IMPRESSIVE SHORTWAVE EARLY
IN THE WEEKEND AS IT LIFTS OUT OF THE BASE OF THE ENTRENCHED LONG
WAVE TROUGH. WHILE ITS SFC REFLECTION WILL ONLY BE AN INVERTED
TROUGH NOSING NORTH OUT OF THE OHIO VALLEY...AN ANOMALOUSLY STRONG
130KT H25 JET WILL HELP IT TO PRODUCE A SWATH OF RAIN THAT SHOULD
STRETCH ACROSS THE BULK OF OUR FORECAST AREA SATURDAY AND PART OF
SATURDAY NIGHT. THE MOISTURE WILL BE ENHANCED BY MARGINALLY UNSTABLE
AIR OVER THE LOWER LAKES...WHERE CONVECTIVE CLOUD DEPTHS WILL LIKELY
EXCEED 20K FT. THIS HAS THE MAKINGS OF A SIGNIFICANT RAINFALL EVENT
NORTHEAST OF BOTH LAKES...WHERE IF ALL THE INGREDIENTS COME
TOGETHER...AMOUNTS OF AN INCH OR MORE WOULD NOT BE OUT OF THE
QUESTION.
ONCE THE SHORTWAVE PASSES SATURDAY EVENING...A WELL ALIGNED
SOUTHWEST FLOW SHOULD SUPPORT A BAND OF LAKE EFFECT RAIN SHOWERS
FROM LAKE ERIE AND THE IAG FRONTIER TO THE EASTERN LAKE ONTARIO
REGION. THE SYNOPTIC RAINS WILL TAPER OFF ELSEWHERE.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS HAS BEEN ADVERTISED FOR SEVERAL DAYS NOW...A HIGHLY POSITIVE PNA
PATTERN WILL BE IN PLACE ACROSS NORTH AMERICA DURING THIS PERIOD.
STRONG RIDGING WILL HOLD FIRM ACROSS THE PACIFIC NORTHWEST WHILE A
POLAR VORTEX WILL BE CENTERED OVER EASTERN CANADA. THIS PATTERN WILL
FAVOR NEAR TO BELOW NORMAL TEMPERATURES THROUGH AT LEAST MID WEEK...
AND LIKELY INTO NEXT WEEKEND.
THE MAIN SYNOPTIC FEATURE DURING THIS EXTENDED PERIOD WILL BE THE
PASSAGE OF A SUB-ARCTIC FRONT LATE MONDAY NIGHT AND TUESDAY. THIS
WILL GENERATE YET ANOTHER ROUND OF SCATTERED SHOWERS FOR OUR
REGION...WITH THE COLD AIR IN ITS WAKE POSSIBLY CHANGING SOME OF THE
LINGERING SHOWERS TUESDAY NIGHT TO WET SNOW SHOWERS ACROSS THE
HIGHER ELEVATIONS. SPEAKING OF SNOW...WHILE THE GENERAL PATTERN IS
STILL EXPECTED TO FAVOR LAKE EFFECT ON WEDNESDAY...THE VARIOUS
PACKAGES HAVE BACKED OFF ON SOME OF THE OTHER INGREDIENTS (MID LEVEL
MOISTURE AND FETCH) NECESSARY FOR NOTEWORTHY ACCUMULATIONS.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
PREFRONTAL SHOWERS WILL COVER CENTRAL AND EASTERN NEW YORK LATE THIS
AFTERNOON AND EVENING AS A NARROW BAND OF FRONTAL CONVECTION
ACCOMPANIES THE COLD FRONT AS IT CROSSES THE REGION THIS EVENING AND
EARLY TONIGHT. EXPECT MAINLY MVFR CEILINGS THIS EVENING WITH PERIODS
OF MVFR VSBYS IN SHOWERS AND SCATTERED THUNDERSTORMS...THEN PARTIAL
CLEARING AND VFR CEILINGS OR SCATTERED CLOUDS OVERNIGHT. SOME VALLEY
FOG MAY FORM OVER THE SOUTHERN TIER BUT SHOULD BE REMOVED FROM
AFFECTING KJHW AS LAKE EFFECT CLOUDS WILL LIKELY COVER MUCH OF
CHAUTAUQUA COUNTY...AND LAKE EFFECT CLOUDS WILL ALSO AFFECT THE
EASTERN LAKE ONTARIO REGION. VFR CONDITIONS SHOULD PREVAIL ON
THURSDAY.
OUTLOOK...
THURSDAY...MAINLY VFR LOWER TO MVFR LATE IN THE DAY.
FRIDAY THROUGH SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
MONDAY...VFR.
&&
.MARINE...
MODERATELY STRONG SOUTHERLY WINDS AHEAD OF AN APPROACHING COLD FRONT
WILL BECOME WESTERLY BEHIND THE FRONT...WHILE COLDER AIR DEEPENS
ACROSS THE LOWER LAKES. THIS WILL CAUSE SCA CONDITIONS TO LINGER
ALONG THE EASTERN SHORES OF THE LAKES THROUGH TONIGHT AND INTO
THURSDAY MORNING ON LAKE ONTARIO.
HIGH PRESSURE BUILDING ACROSS THE NATIONS MIDSECTION WILL MAINTAIN A
WESTERLY FLOW WITH PERIODIC BREEZY CONDITIONS DURING THE AFTERNOONS
THROUGH THE WEEK.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR LEZ040-041.
SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR
LOZ045.
SMALL CRAFT ADVISORY FROM 2 AM TO 11 AM EDT THURSDAY FOR
LOZ044.
&&
$$
SYNOPSIS...WCH
NEAR TERM...WCH
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...WCH
MARINE...WCH