Area Forecast Discussion


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