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| Area Forecast Discussion for Buffalo, NY | ||
| AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BUFFALO NY 719 AM EST WED NOV 19 2008 .SYNOPSIS... WEAK HIGH PRESSURE WILL QUICKLY MOVE ACROSS THE FORECAST AREA TODAY...AND THIS WILL TEMPORARILY BRING AN END TO THE LAKE EFFECT SNOW SHOWERS. A CLIPPER LOW WILL THEN MOVE FROM THE UPPER PENINSULA OF MICHIGAN TO NEAR BUFFALO BY THURSDAY MORNING...BEFORE RACING TO THE NEW ENGLAND COAST THURSDAY EVENING. THIS SYSTEM WILL PRODUCE A GENERAL LIGHT SNOW FOR THE BULK OF WESTERN NEW YORK IN THE PROCESS WITH MOST AREAS PICKING UP AN INCH OR TWO ACCUMULATION. && .NEAR TERM /THROUGH TONIGHT/... -- Changed Discussion --AS OF 1215Z...THE LAST 3 HOURS OR SO HAVE SEEN A GENERAL WEAKENING TREND IN THE LAKE SNOWS FROM ROCHESTER WESTWARD. OVER FAR WESTERN NY...THE ACTIVITY HAS BROKEN UP ENOUGH TO DROP POPS BACK INTO THE SCATTERED RANGE FOR TODAY...WITH LITTLE ADDITIONAL ACCUMULATION EXPECTED. IN THE ROCHESTER AREA AND WESTERN PORTIONS OF THE FINGER LAKES...THE SNOWS HAVE BECOME DISORGANIZED ENOUGH TO ALLOW FOR THE DROPPING OF THE ADVISORY FOR MONROE AND ONTARIO COUNTIES...THOUGH HAVE LEFT LIKELY POPS AND MINOR ACCUMS INTACT UNTIL THE ACTIVITY SHIFTS EAST INTO THE EASTERN FINGER LAKES LATER THIS MORNING. DURING THE COURSE OF TODAY...LOW LEVEL RIDGING CURRENTLY EXTENDING FROM OHIO TO SOUTHERN ONTARIO WILL SHIFT EASTWARD INTO WESTERN NY STATE...BEFORE SLIDING EAST INTO EASTERN NY THIS AFTERNOON. LARGE-SCALE SUBSIDENCE...DRY AIR ADVECTION...AND INCREASING LOW-LEVEL SHEAR ASSOCIATED WITH THIS FEATURE WILL CAUSE ANY EXISTING LAKE EFFECT ACTIVITY TO CONTINUE TO WIND DOWN WITH TIME...WHILE THE BACKING STEERING FLOW CAUSES THE WEAKENING ACTIVITY TO SLOWLY SHIFT NORTHWARD AND EASTWARD. THE ACTIVITY WILL WIND DOWN FIRST OFF OF LAKE ERIE AND THE WESTERN HALF OF LAKE ONTARIO DURING THE MORNING AS THE AXIS OF THE SURFACE RIDGE ARRIVES IN THESE AREAS FIRST...WITH ONLY MINOR ADDITIONAL ACCUMULATIONS EXPECTED THROUGH NOONTIME. FARTHER TO THE EAST...THE LAKE SNOWS WILL HANG ON A BIT LONGER...BUT WILL ALSO GRADUALLY BECOME MORE CONFINED TO NORTHERN CAYUGA/OSWEGO COUNTIES THROUGH THE LATE MORNING/EARLY AFTERNOON AS THE STEERING WINDS BECOME MORE WEST-NORTHWESTERLY. DURING THE REMAINDER OF THE AFTERNOON...THE AFOREMENTIONED SURFACE RIDGING AND SUBSIDENCE SHOULD INCREASE ENOUGH TO SQUELCH THE REMAINING LAKE SNOWS...WITH JUST A FEW SCATTERED SNOW SHOWERS LEFT AROUND MEXICO BAY BY THE END OF THE DAY. GIVEN CURRENT SNOWFALL RATES AND THE AFOREMENTIONED EXPECTED TRENDS...AREAS SOUTHEAST OF LAKE ONTARIO MAY SEE AS MUCH AS AN ADDITIONAL 2-4" OF ACCUMULATION WITHIN THE MOST PERSISTENT BANDS TODAY...WHICH SHOULD GENERALLY BE FROM NORTHEASTERN WAYNE COUNTY EASTWARD ACROSS NORTHERN CAYUGA COUNTY AND WESTERN OSWEGO COUNTY. FARTHER WEST...ANOTHER INCH OR TWO CAN BE EXPECTED FROM THE CITY OF ROCHESTER EASTWARD ACROSS THE REMAINDER OF WAYNE COUNTY. CONSIDERING THESE SNOWFALL AMOUNTS...HAVE OPTED TO LEAVE THE REMAINING LAKE SNOW HEADLINES IN PLACE AT THIS TIME. ONCE THE LAKE EFFECT WINDS DOWN TODAY...OUR ATTENTION WILL THEN SHIFT TO THE CLIPPER SYSTEM THAT IS EXPECTED TO DROP SOUTHEAST INTO THE UPPER GREAT LAKES TODAY...THEN FURTHER SOUTHEAST INTO WESTERN NY STATE TONIGHT. THIS FEATURE WILL BRING AN INCREASE IN MID AND UPPER CLOUDS TO THE AREA THIS AFTERNOON...WITH A GENERAL LIGHT SNOWFALL THEN OVERSPREADING THE AREA FROM NORTHWEST TO SOUTHEAST TONIGHT AS MOISTURE DEEPENS...AND MODEST WARM AIR ADVECTION/INCREASING JET DYNAMICS PROVIDE FORCING. AT THIS POINT...IT APPEARS WE ARE LOOKING AT THE POTENTIAL FOR 1-2" OF ACCUMULATION ALONG AND NEAR THE TRACK OF THE SURFACE LOW/CORRESPONDING ZONE OF BETTER LOW LEVEL CONVERGENCE ACROSS SOUTHERN ONTARIO AND INTO FAR WESTERN NY TONIGHT...WITH MUCH LESSER AMOUNTS FURTHER NORTH AND EAST ACROSS THE FINGER LAKES AND NORTH COUNTRY...WHICH WILL BE FURTHER AWAY FROM THE BETTER JET DYNAMICS. HAVE THEREFORE TAILORED POPS ACCORDINGLY...RAGING FROM CATEGORICAL ACROSS THE WEST TO JUST CHANCE ACROSS THE EAST.-- End Changed Discussion -- && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... A DEEP LONGWAVE TROUGH WILL REMAIN IN PLACE OVER EASTERN CANADA AND THE GREAT LAKES REGION DURING THIS PERIOD...WITH SOME OF THE COLDEST WEATHER OF THE YOUNG SEASON EXPECTED TO MOVE INTO OUR REGION. SFC TEMPS DURING THIS PERIOD WILL AVERAGE SOME 7 TO 10 DEG F BELOW NORMAL WHILE MOST AREAS WILL PICK UP AT LEAST A COATING OF FERSH SNOW. THE DETAILS... A WEAK CLIPPER CENTERED NEAR BUFFALO ON THURSDAY MORNING WILL QUICKLY MAKE ITS WAY TO THE SOUTHERN NEW ENGLAND COAST BY THURSDAY NIGHT...BUT NOT BEFORE IT WILL FINISH PRODUCING A GENERAL LIGHT SNOW ACROSS MUCH OF THE REGION. SNOWFALL AMOUNTS DURING THE DAY THURSDAY WILL AVERAGE AN INCH OR SO...WITH SLIGHTLY HIGHER AMOUNTS EXPECTED OVER CHAUTAUQUA COUNTY WHERE SOME AFTERNOON LAKE ENHANCEMENT SHOULD SUPPORT AMOUNTS UP TO 2 INCHES. THE EXCEPTION TO THE GENERAL SNOWFALL WILL BE ACROSS THE NORTH COUNTRY WHERE THE NORTHERN EDGE OF THE SNOW SHIELD WILL BE IN THE FORM OF FLURRIES AND LIGHT SNOW SHOWERS. FOR THIS AREA...SNOWFALL WILL STRUGGLE TO COAT THE GROUND. IN THE WAKE OF THE CLIPPER THURSDAY NIGHT...A VIGOROUS BUT MOISTURE STARVED SHORTWAVE WILL DIG ACROSS THE GREAT LAKES AND OHIO VALLEY INTO THE BASE OF THE TROF. THIS WILL DEEPEN THE ALREADY FULL LATITUDE TROF WHILE SENDING A REINFORCING SURGE OF VERY COLD AIR SOUTHWARDS FROM ONTARIO. AS ONE WOULD EXPECT AT THIS OF YEAR...THIS WILL ONCE AGAIN OPEN THE DOOR FOR LAKE SNOWS OFF BOTH LAKES. AN AIRMASS WITH H85 TEMPS OF -16C ARE FORECAST TO DROP OVER LAKES ERIE AND ONTARIO DURING THE COURSE OF THURSDAY NIGHT AND FRIDAY... WITH A BOUNDARY LAYER FLOW AVERAGING SOMEWHERE IN THE VCNTY OF 320 TO 340. OFF LK ONTARIO...THIS WILL PROMOTE MULTIPLE BANDS OF LAKE SNOW WHICH WILL RESULT IN WIDESPREAD SNOW SHOWERS FROM THE IAG FRONTIER AND GENESEE VALLEY EAST TO SYRACUSE. THE AREA THAT WILL LIKELY BE MOST AFFECTED WILL BE FROM ROCHESTER AND MOUNT MORRIS EASTWARD ACROSS THE FINGER LAKES REGION. MEANWHILE OFF LK ERIE...THE 00Z OPERATIONAL GFS AND THE BULK OF THE 21Z SREF MEMBERS ARE IN AGREEMENT THAT THE MOST WIDESPREAD LAKE SNOWS THURSDAY NIGHT AND FRIDAY WILL BE FROM WESTERN CHAUTAUQUA COUNTY WESTWARD ACROSS PENNSYLVANIA INTO OHIO. AS A RESULT OF -16C H85 TEMPS ON FRIDAY...SFC TEMPS WILL STRUGGLE TO THE FREEZING MARK NEAR THE LAKE SHORES WHILE MOST INLAND AREAS WILL NOT MAKE IT OUT OF THE 20S. A WNW WIND OF 10 TO 15 MPH WILL THEN ADD TO THE WINTRY FEEL BY PRODUCING WIND CHILLS THAT WILL LARGELY BE IN THE TEENS FOR THE BULK OF THE DAY. THE DEEP FLOW OUT OF THE YUKON WILL CONTINUE FRIDAY NIGHT WHILE A SFC BASED RIDGE WILL MAKE ITS WAY ACROSS THE GREAT LAKES AND OHIO VALLEY. WHILE A SUBSIDENCE INVERSION FROM THE HIGH WILL TEND TO LESSEN THE LAKE SNOWS OFF LK ERIE...THERE SHOULD CERTAINLY BE ENOUGH SNOW SHOWERS AROUND TO THE SOUTHEAST OF BOTH LAKES FOR ADDITIONAL ACCUMULATIONS. OTHERWISE...FRIDAY NIGHT COULD BE THE COLDEST NIGHT OF THE SEASON WITH TEMPS RANGING FROM 10 TO 15 ACROSS THE VALLEYS OF THE WRN SOUTHERN TIER AND ALSO ON THE TUG...TO THE LOWER 20S ALONG THE LAKE SHORES. && .LONG TERM /SATURDAY THROUGH TUESDAY/... GENERAL TROFFINESS WILL STILL BE IN PLACE ACROSS THE GREAT LAKES FOR THE BULK OF THIS PERIOD...BUT UNLIKE PREVIOUS DAYS WHEN THE FLOW WAS COMING OUT OF THE YUKON...IT IS LOOKING MORE AND MORE FAVORABLE FOR PACIFIC AIR TO BECOME INVOLVED. WHILE OUR MERCURY LEVELS WILL STILL LIKELY AVERAGE BELOW NORMAL...THEY SHOULD CLIMB BACK TOWARDS NORMAL BY THE END OF THE PERIOD. WE WILL STILL BE IN A DEEP COLD AIR MASS SATURDAY WITH 850 MB TEMPERATURES MINUS 14 TO MINUS 16C. ONE MORE VORTICITY MAX WILL SLIDE SOUTHEAST ACROSS THE REGION ON THE WEST SIDE OF THE PROGRESSING UPPER TROUGH. TEMPERATURES WILL BE RUNNING AS MUCH AS 10 TO 15 DEGREES F BELOW NORMAL WITH LAKE EFFECT SNOW SHOWERS REMAINING SOUTHEAST OF THE LAKES IN THE NORTHWEST STEERING FLOW. HIGH PRESSURE WILL BUILD EASTWARD FROM THE OHIO VALLEY TO THE VIRGINIAS SATURDAY NIGHT AND SUNDAY. SOME LINGERING LAKE EFFECT IS STILL EXPECTED SOUTHEAST OF LAKE ONTARIO SATURDAY NIGHT BUT THERE WILL BE WARM ADVECTION ALOFT WHICH WILL PUT AN END TO IT BY SUNDAY MORNING. SOME PRETTY BIG MODEL DIFFERENCE REMAIN IN PLACE FOR MONDAY AND TUESDAY BETWEEN THE GFS AND ECMWF. THE UPPER LOW CLOSES OFF MORE AND IS SLOWER ON THE ECMWF. WE WILL GO CLOSER TO THE ECMWF SOLUTION AT THIS TIME. LOW PRESSURE TRACKING EASTWARD NEAR US WILL BRING ADDITIONAL WARMING AND A CHANCE OF RAIN OR SNOW MONDAY. COLDER ALOFT AFTER THE LOW MOVES THROUGH FOR TUESDAY. WE WILL GO FOR A CHANCE OF RAIN OR SNOW THAT DAY TOO BASED ON BOUNDARY LAYER TEMPERATURES. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... NARROW BANDS OF LAKE EFFECT SNOW WILL CONTINUE DOWNWIND OF THE INTO THIS MORNING...BEFORE GRADUALLY WINDING DOWN AS THE AXIS OF A LOW LEVEL RIDGE WORKS ACROSS THE AREA DURING THE LATE MORNING AND AFTERNOON ALONG WITH INCREASING SUBSIDENCE AND SHEAR. IN GENERAL...CONDITIONS WILL BE VFR THOUGH SUBJECT TO REDUCTIONS TO MVFR/IFR WITHIN ANY LAKE EFFECT...WHICH WILL BE MOST LIKELY FROM KROC EASTWARD TO KFZY SOUTH OF LAKE ONTARIO. TONIGHT...A CLIPPER SYSTEM WILL DROP SOUTHEAST ACROSS THE GREAT LAKES REGION...BRINGING PERIODS OF LIGHT SNOW AND ASSOCIATED MVFR/IFR CONDITIONS TO THE AREA. OUTLOOK... THURSDAY...MVFR/IFR IN LIGHT SNOW. FRIDAY AND SATURDAY...LOCAL IFR LAKE EFFECT SNOW SOUTHEAST OF THE LAKES. SUNDAY...VFR. && .MARINE... NO FLAGS SHOULD BE NEEDED FOR THE NEXT FEW DAYS ACROSS LAKES ERIE AND ONTARIO AS HIGH PRESSURE OVER THE REGION EARLY TODAY WILL GIVE WAY TO A WEAK CLIPPER LOW TONIGHT AND THURSDAY. THE SFC PRESSURE GRADIENT WILL BE RELATIVELY WEAK TODAY...AND WHILE THIS GRADIENT WILL TIGHTEN TONIGHT IN ADVANCE OF THE CLIPPER...THE SOUTHERLY FLOW WILL KEEP THE HIGHEST WAVES OVER CANADIAN WATERS. THE WEAK CLIPPER WILL THEN PASS FROM THE LOWER GREAT LAKES TO THE NEW ENGLAND COAST DURING THE COURSE OF THURSDAY...WITH A RELATIVELY WEAK SFC GRADIENT KEEPING WINDS AND WAVES BELOW SMALL CRAFT ADVISORY CRITERIA. && .BUF WATCHES/WARNINGS/ADVISORIES... -- Changed Discussion --NY...LAKE EFFECT SNOW ADVISORY UNTIL NOON EST TODAY FOR NYZ006. LAKE EFFECT SNOW WARNING UNTIL NOON EST TODAY FOR NYZ004-005. MARINE...NONE.-- End Changed Discussion -- && $$ SYNOPSIS...RSH NEAR TERM...JJR SHORT TERM...RSH LONG TERM...RSH/SAGE AVIATION...JJR/SFM MARINE...RSH US Dept of Commerce National Oceanic and Atmospheric Administration National Weather Service 1325 East West Highway Silver Spring, MD 20910 Page Author: NWS Internet Services Team Page last modified: Aug 26th, 2008 18:04 UTC Disclaimer Credits Glossary Privacy Policy About Us Career Opportunities 192.168.15.112 | ||
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