Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/19/13


AREA FORECAST DISCUSSION
NWS ALBANY NY
434 PM EST THU JAN 17 2013 .SYNOPSIS... A COLD FRONT WILL SETTLE SOUTH OF THE REGION TONIGHT. A STORM SYSTEM PASSING WELL OFF THE MID ATLANTIC COAST WILL BRING SOME CLOUDS TO THE REGION THIS EVENING...AND PERHAPS A FEW SNOW SHOWERS OR FLURRIES FOR SOUTHEAST AREAS. HIGH PRESSURE WILL BUILD IN FOR FRIDAY...BRINGING FAIR BUT COLD CONDITIONS. ANOTHER STORM SYSTEM WILL APPROACH FROM THE GREAT LAKES FRIDAY NIGHT AND SATURDAY...BRINGING CLOUDS AND SOME SNOW SHOWERS...AND FOLLOWED BY ANOTHER SURGE OF VERY COLD AIR FOR SUNDAY THROUGH EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... AS OF 430 PM EST...A COLD FRONT CONTINUES TO SETTLE SOUTHWARD ACROSS THE REGION...AND IS CURRENTLY APPROACHING THE SE CATSKILLS INTO THE MID HUDSON VALLEY REGION. LITTLE IN THE WAY OF PRECIPITATION IS ASSOCIATED WITH THIS FRONT AT THIS TIME. MEANWHILE...TEMPS ARE GRADUALLY FALLING INTO THE TEENS ACROSS THE SOUTHERN ADIRONDACKS...AND THROUGH THE 20S FOR AREAS NORTH OF THE MOHAWK RIVER VALLEY AND CAPITAL DISTRICT. A THICK CANOPY OF HIGH AND MID LEVEL CLOUDS CONTINUES TO COVER MOST OF THE REGION...IN ASSOCIATION WITH MOISTURE STREAMING NORTHWARD IN ASSOCIATION WITH THE STRONG UPPER LEVEL STORM SYSTEM TRAVERSING THE SOUTHEAST STATES. IN ADDITION...SOME LOWER CLOUDS CONTINUE TO AFFECT AREAS FURTHER N AND W IN ASSOCIATION WITH LOW LEVEL COLD ADVECTION...AND SOME ADDITIONAL MOISTURE CONTRIBUTED FROM THE GREAT LAKES. THE LATEST HRRR INDICATES THAT AS THE MID LEVEL CLOUDS THICKEN MORE THIS EVENING...THERE COULD BE SOME FEEDER/SEEDER PROCESSES WITH THE LOWER CLOUD DECK WHICH COULD PRODUCE SOME LIGHT SNOW SHOWERS OR FLURRIES FOR AREAS MAINLY SOUTH AND SOUTHEAST OF THE GREATER CAPITAL DISTRICT...PARTICULARLY ACROSS PORTIONS OF THE MID HUDSON VALLEY...EXTREME SOUTHERN BERKSHIRES...AND NW CT. HAVE INCLUDED MENTION OF FLURRIES OVERNIGHT IN MOST OF THESE AREAS...ALONG WITH MENTION OF SLIGHT CHC POPS FOR SNOW SHOWERS ACROSS THE MID HUDSON VALLEY AND NW CT. IN THIS REGION...CAN NOT COMPLETELY RULE OUT A COATING OF SNOW IN SOME AREAS BY DAYBREAK. THE HIGH/MID LEVEL CLOUD CANOPY SHOULD GRADUALLY THIN FROM NW TO SE...STARTING AROUND MIDNIGHT...AND CONTINUING THROUGH DAYBREAK. THIS RAISES A RATHER CHALLENGING TEMPERATURE FORECAST...ESP FOR NORTHERN AREAS...AS ANY PERIOD OF CLEAR SKIES ALONG WITH DECREASING WIND AND AT LEAST SOME SNOW COVER COULD LEAD TO A QUICK DROP IN TEMPS. HAVE SIDED WITH...OR EVEN WENT A BIT BELOW THE COLDER MOS FOR MIN TEMPS OVERNIGHT ACROSS NORTHERN AREAS...WITH WIDESPREAD SUBZERO MINS EXPECTED. FURTHER SOUTH...HAVE SIDED WITH THE COLDER MET MOS IN MOST AREAS...ALTHOUGH TOOK A BLEND OF THE MAV/MET MOS ACROSS SOUTHERN AREAS WHERE CLOUDS COULD LAST LONGER. ACROSS NORTHERN AREAS WHERE SUBZERO TEMPS ARE EXPECTED...WINDS SHOULD DROP TO BELOW 5 MPH...AND THEREFORE NO WIND CHILL HEADLINES ARE INDICATED. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... FRIDAY...A PERIOD OF MOSTLY SUNNY SKIES IS EXPECTED THROUGH MUCH OF THE DAY IN VALLEY AREAS...BEFORE A COMBINATION OF WARM ADVECTION...AND SOME LAKE MOISTURE WITH A BACKING NORTHWEST TO WEST WIND ALLOW CLOUDS TO REDEVELOP LATER IN THE DAY ACROSS THE WESTERN MOHAWK VALLEY/ADIRONDACKS...AND PERHAPS ACROSS THE SCHOHARIE VALLEY/HELDERBERGS. HAVE SIDED WITH THE COLDER SIDE OF MOS FOR MAX TEMPS...WITH GENERALLY 20-25 IN VALLEY AREAS FROM ALBANY N AND W...AND 25-30 IN VALLEY AREAS SOUTH OF ALBANY...WHILE MOST HIGHER ELEVATIONS ONLY REACH THE TEENS. SOME SNOW SHOWERS ARE EXPECTED TO DEVELOP BY AFTERNOON ACROSS THE WESTERN ADIRONDACKS AND MOHAWK VALLEY REGION. FRIDAY NIGHT-SAT...AS A STRONG CLIPPER TYPE SYSTEM APPROACHES FROM THE GREAT LAKES REGION...A SURGE OF MID LEVEL WARM ADVECTION IS EXPECTED TO PRODUCE ABUNDANT CLOUDS FOR LATER FRI NIGHT INTO AT LEAST SAT MORNING...AND PERHAPS WELL INTO SAT AFTERNOON ACROSS NORTHERN AREAS...WHERE ISENTROPIC LIFT WILL PERSIST. ALSO...AREAS OF SNOW SHOWERS AND FLURRIES WILL OCCUR IN NORTHERN AREAS FRI NT INTO SAT AM. SOME COATINGS WILL BE POSSIBLE IN VALLEY AREAS NORTH OF THE CAPITAL REGION...WITH PERHAPS 1-4 INCHES ACROSS PORTIONS OF THE WESTERN MOHAWK VALLEY/ADIRONDACK REGION. TEMPS FRI NT SHOULD INITIALLY FALL QUICKLY...BEFORE RISING LATER IN THE EVENING THROUGH DAYBREAK SAT. HAVE GENERALLY WENT WITH THE COLDER SIDE OF GUIDANCE FOR MINS...ESP ACROSS NORTHERN AREAS. ON SAT...DESPITE A DEVELOPING SOUTHWEST FLOW...CLOUDS AND A LOW LEVEL INVERSION MAY PREVENT TEMPS FROM RISING TO THE WARMER MAV MOS NUMBERS. HAVE SIDED WITH THE COOLER MET MOS IN MOST AREAS...AND HAVE EVEN UNDERCUT BY A FEW ACROSS NORTHERN AREAS...WITH MID 30S EXPECTED ACROSS THE SOUTHERN ADIRONDACKS AND LAKE GEORGE/SARATOGA REGION...AND UPPER 30S TO LOWER 40S IN VALLEY AREAS FURTHER SOUTH. HOWEVER...ACROSS PORTIONS OF THE SE CATSKILLS AND MID HUDSON VALLEY...MORE SUNSHINE...AND A GUSTY DOWNSLOPING SW FLOW SHOULD BOOST TEMPS INTO THE 45-50 RANGE. SAT NT...OUR REGION SHOULD REMAIN WITHIN THE WARM SECTOR OF THE APPROACHING CLIPPER. AS A COLD FRONT APPROACHES FROM THE NORTHWEST LATER AT NIGHT...CLOUDS AND SOME SNOW SHOWERS SHOULD DEVELOP BY DAYBREAK SUNDAY ACROSS N/W AREAS...WHERE CHC POPS ARE INDICATED. INCREASING CLOUDS...AND A BRISK S/SW WIND SHOULD PREVENT TEMPS FROM FALLING MUCH...AND THEREFORE HAVE GONE ABOVE MOS...WITH UPPER 20S TO MID 30S EXPECTED REGIONWIDE FOR MINS. && .LONG TERM /SUNDAY THROUGH THURSDAY/... ...BELOW NORMAL TEMPERATURES WILL PERSIST THROUGH THE EXTENDED PERIOD. NORMAL TEMPERATURES FOR THE PERIOD JAN 20TH THROUGH 23RD: ALBANY: HIGHS AROUND 30. LOWS IN THE MID TEENS. GLENS FALLS: HIGHS IN THE UPPER 20S. LOWS IN THE SINGLE DIGITS. POUGHKEEPSIE: HIGHS IN THE MID 30S. LOWS IN THE MID TEENS. BENNINGTON: HIGHS AROUND 30. LOWS NEAR 10. PITTSFIELD: HIGHS IN THE UPPER 20S. LOWS NEAR 10. MODEL GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT IN REGARDS TO THE LONGWAVE PATTERN FOR THE PERIOD WITH A LARGE TROUGH COVERING THE EASTERN 2/3 OF THE CONUS WITH SHORT WAVES ROTATING ABOUT AN UPPER LOW OVER HUDSON/S BAY CANADA AND RIDGING ALONG THE WEST COAST. NOW...EVEN THE DIFFERENCES IN THE LONG RANGE MODELS WERE IN PRETTY GOOD AGREEMENT. A POTENT CLIPPER...TRACKING ACROSS THE GREAT LAKES...WILL DRIVE AN ARCTIC FRONT ACROSS THE REGION ON SUNDAY. THIS FRONT STILL LOOKS TO HAVE DECENT UPPER LEVEL DYNAMICS AND A SHARP THERMAL GRADIENT ASSOCIATED WITH IT...SO A ROUND OF SNOW SHOWERS/SQUALLS IS POSSIBLE WITH THE FRONTAL PASSAGE. A SOUTH OR SOUTHWEST WIND WILL SHIFT WEST-NORTHWEST AND DRIVE H850 TEMPS FROM ABOUT -2C EARLY...TO NEARLY -20C BY LATE IN THE DAY! TEMPERATURES MIGHT ACTUALLY SPIKE IN THE MORNING...THEN DROP DURING THE AFTERNOON ACROSS THE ENTIRE REGION. HOWEVER THIS FAR OUT...WE JUST USED THE CLIMATOLOGICAL DIURNAL TREND IN THE GRIDS SINCE A CHANGE IN THE ARRIVAL OF THIS REALLY COLD AIR WOULD CHANGE HOURLY TEMPERATURES QUITE A BIT. BY SUNDAY NIGHT WITH 850 MB TEMPERATURES LOOK TO HAVE DROPPED TO BETWEEN -15 TO -20 C ACROSS THE FORECAST AREA. A WESTERLY WIND OF 10 TO 20 MPH WILL MAKE IT FEEL EVEN COLDER. WIND CHILL VALUES MAY REACH ADVISORY CRITERIA (-20F) ACROSS THE SOUTHERN ADIRONDACKS AND THE HIGHER TERRAIN OF SOUTHERN VERMONT. WILL HAVE MENTION IN OUR HAZARDOUS WEATHER OUTLOOK. SHORT WAVES ROTATING ABOUT THE UPPER LOW WILL BRING REINFORCING SHOTS OF COLDER AIR TO THE REGION AS ADDITIONAL CLIPPER SYSTEMS MOVE THROUGH MONDAY THROUGH WEDNESDAY. THIS WILL KEEP CLOUDS AND THE THREAT OF SNOW SHOWERS IN THE FORECAST...ESPECIALLY DOWNWIND OF LAKE ONTARIO. AT THIS POINT THE SYSTEMS WILL HAVE LIMITED MOISTURE ASSOCIATED WITH THEM SO ANY PRECIPITATION/SNOW SHOULD BE LIGHT. ONE THING TO WATCH ON TUESDAY. IT STILL APPEARS THAT A STORM IN THE SOUTHERN JETSTREAM SHOULD MOVE WELL SOUTH AND EAST OF OUR REGION OUT INTO THE OCEAN. HOWEVER...EVEN IF IT DOES...INTERACTION BETWEEN THIS SYSTEM AND A POSSIBLE SHORTWAVE REINFORCING THE TROUGH OVER US...MIGHT PRODUCE BROAD ASCENT TO GIVE OUR ENTIRE AREA LIGHT SNOW OR SNOW SHOWERS TUESDAY. AGAIN...THIS SCENARIO IS NOT ETCHED IN STONE...AND FOR NOW...ONLY WENT SLIGHT CHANCES IN AREAS OUTSIDE THE ELEVATED TERRAIN TO THE WEST OF THE HUDSON VALLEY WHERE WE WENT LOW POPS DUE TO MORE LAKE AVAILABLE EFFECT MOISTURE. AS THE AFOREMENTIONED OCEAN STORM WINDS UP LATE TUESDAY...IT LOOKS TO DRIVE ANOTHER SURGE OF ARCTIC AIR OUR WAY FOR TUESDAY...WITH SOME INDICATIONS THAT H850 TEMPERATURES COULD BE EVEN COLDER (IN THE -20C TO -25C RANGE). OF COURSE THIS NEW SURGE OF ARCTIC AIR COULD COME WITH ANOTHER ROUND OF SNOW SHOWERS/SNOW SQUALLS AND LAKE EFFECT SNOW. INITIALLY THE ENVIRONMENT LOOKS SOMEWHAT SHEARED FOR SIGNIFICANT LAKE EFFECT ACCUMULATIONS. HOWEVER...BY LATE TUESDAY INTO WEDNESDAY...THE FLOW LOOKS TO BECOME MORE CYCLONIC WITH LESS SHEAR AND VERY COLD AIR PRODUCING POTENTIAL EXTREME SLANTWISE INSTABILITY OFF LAKE ONTARIO. WE WILL MONITOR THE LAKE EFFECT POTENTIAL THROUGH THE PERIOD. TEMPERATURES WILL TO TOP OUT IN THE 30S TO NEAR 40 SUNDAY IN THE HUDSON VALLEY (THE WARMEST READINGS AROUND POUGHKEEPSIE). HIGHER TERRAIN WILL SEE HIGHS ONLY 25-30. AGAIN...TEMPERATURES COULD DROP DURING THE AFTERNOON. OVERNIGHT LOWS SUNDAY NIGHT THROUGH WEDNESDAY LOOK TO TUMBLE TO THE TEENS FROM THE TRI-CITIES SOUTHWARD...AROUND ZERO TO SINGLE NUMBERS FURTHER NORTH AND WEST. THIS ASSUMES SOME WIND (AS OPPOSED TO CALM CONDITIONS). IF THE WIND WERE TO DECOUPLE ANY OF THESE NIGHTS WITH EVEN A PARTIALLY CLEAR SKY...OVERNIGHT LOWS COULD BE A LOT COLDER...ESPECIALLY UP NORTH. DAYTIME HIGHS MONDAY THROUGH THURSDAY LOOK TO LOOK TO BE 20-25 IN THE HUDSON VALLEY FROM ALBANY SOUTHWARD...TEENS FURTHER NORTH...WITH SOME READINGS AROUND 10 ACROSS THE ADIRONDACKS. THESE VALUES MIGHT NOT BE COLD ENOUGH BUT AS WE GET CLOSER TO THIS TIME PERIOD...WE WILL ADJUST THEM AS NEEDED. && .AVIATION /21Z THURSDAY THROUGH TUESDAY/... A COLD FRONT HAS PASSED KGFL...AND WILL PASS KALB EARLY IN THE AFTERNOON....KPOU NOT UNTIL LATE AFTERNOON OR EVENING. DESPITE THE COLD FRONTAL PASSAGE...VFR CONDITIONS WILL PREVAIL. THE MAIN FACTOR WITH THE COLD FRONT WILL BE A WIND SHIFT FROM W TO N. THE WIND WILL BE GUSTY AT TIMES UP TO 20 MPH...ESPECIALLY WITH THE PASSAGE OF THE FRONT. BROKEN VFR CIGS AT KGFL/KALB AND KPSF WILL BE IN THE 3500-4000 FEET AGL UNTIL EARLY EVENING. AT KPOU...MOST CLOUDS WILL NOT BE "SENSIBLE" (OVER 12,000 FEET). TONIGHT...MOST IF NOT ALL OF THE SENSIBLE CLOUDS WILL BE GONE. THE ONLY EXCEPTION IS SOME VFR CIGS AROUND 4000 FEET MIGHT APPROACH KGFL FROM MOISTURE OF LAKE CHAMPLAIN AT TIMES THROUGH EARLY FRIDAY. A NORTH WIND WILL CONTINUE AROUND 10KTS THROUGH EARLY TOMORROW...BECOMING LIGHTER AND MORE VARIABLE BY LATE IN THE DAY. OUTLOOK... FRI-SAT...VFR...NO SIG WX. SUN...MAINLY VFR. CHC -SHSN. MON...VFR. SLIGHT CHC -SHSN. TUE...VFR. CHC SUB-VFR CIG -SHSN. && .HYDROLOGY... MAINLY DRY AND COLD WEATHER WILL OCCUR OVER THE NEXT FIVE DAYS. WHILE SOME SNOW SHOWERS ARE POSSIBLE OVER THE NEXT FEW DAYS ACROSS NORTHERN AREAS...PRECIPITATION AMOUNTS WILL BE LIGHT AND IN THE FORM OF SNOW. COLD TEMPERATURES...ESPECIALLY EARLY NEXT WEEK...WILL CAUSE RIVER AND LAKE ICE TO FORM AND THICKEN. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...KL/HWJIV/FRUGIS NEAR TERM...KL SHORT TERM...KL LONG TERM...HWJIV/IAA AVIATION...HWJIV HYDROLOGY...KL/FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
910 AM EST THU JAN 17 2013 .SYNOPSIS... AN ARCTIC COLD FRONT WILL CROSS THE REGION TODAY. THIS FRONT WILL BRING SOME SNOW SHOWERS TO THE ADIRONDACKS FOR THIS MORNING...FLURRIES ELSEWHERE. THEN...IT WILL TURN COLD AND BLUSTERY TONIGHT AND TOMORROW. A WARM FRONT WILL ALLOW TEMPERATURES TO RETURN ABOVE NORMAL AGAIN BRIEFLY FOR SATURDAY BEFORE ANOTHER STRONG COLD FRONT RETURNS COLD WEATHER TO THE AREA FOR SUNDAY INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 900 AM...SNOW SHOWERS OR FLURRIES HAVE EXPANDED WELL PAST THE ADIRONDACKS PARK...INTO THE GREATER CAPITAL DISTRICT. THESE SNOW SHOWERS/FLURRIES ARE WELL AHEAD OF AN ARCTIC FRONT...STILL NORTH OF THE REGION...POISED TO COME DOWN DURING THE DAY...PROBABLY NOT CLEARING OUR SOUTHERN AREAS UNTIL THIS EVENING. MEANWHILE...TEMPERATURES HAVE ETCHED UPWARD AHEAD OF THE FRONT...SO HAD TO MAKE ADJUSTMENTS ON HIGH TEMPS TODAY...ONLY BY A COUPLE OF DEGREES. THINKING IS TEMPERATURES SHOULD LEVEL OFF LATER THIS MORNING (EXCEPT MID HUDSON VALLEY AND LOWER LITCHFIELD) WHERE THEY WILL RISE INTO THE AFTERNOON BEFORE FALLING. SNOW SHOWERS SHOULD ONLY ADD MINOR ACCUMULATIONS...OF AROUND AN INCH OR LESS IN SPOTS ACROSS THE ADIRONDACKS. LITTLE OR NO ACCUMULATIONS EXPECTED ELSEWHERE. THE ARCTIC BOUNDARY SHOULD CROSS THE ADIRONDACK REGION BY THE MID MORNING HOURS. AS THIS BOUNDARY CONTINUES TO MOVE ACROSS THE REGION...SNOW SHOWERS WILL BECOME MORE ISOLD. 00Z NAM12 GUIDANCE...AS WELL AS THE LOCAL HIRES WRF AND THE 3KM HRRR GUIDANCE ALL SHOW THIS BAND OF SNOW SHOWERS FALLING APART AS IT REACHES THE MOHAWK VALLEY/SARATOGA AREA/SRN VT/CAPITAL REGION AROUND NOON DUE TO LITTLE MOISTURE AVAILABLE...SO WILL CONTINUE WITH ONLY GO WITH SLIGHT CHC POPS OUTSIDE THE ADIRONDACKS. WHILE THERE MAY BE A FEW FLURRIES FOR THESE VALLEY AREAS LATE THIS MORNING/EARLY THIS AFTN...NO SNOW ACCUMULATION IS ANTICIPATED. THE FRONT WILL THEN CONTINUE SOUTHEAST ACROSS THE CATSKILLS/MID HUDSON VALLEY/BERKSHIRES/NW CT FOR THIS AFTN...BUT WITH NO PRECIP ASSOCIATED WITH IT. THE MAIN IMPACT WITH THIS FRONT WILL BE THE SHARP TEMPERATURE GRADIENT. MAX TEMPS WILL OCCUR AHEAD OF THE FRONT...WITH TEMPS RANGING FROM NEAR 20 IN THE ADIRONDACKS TO NEAR 40 IN THE MID HUDSON VALLEY. ONCE THE FRONT MOVES THROUGH...TEMPS WILL RAPIDLY FALL...ALONG WITH GUSTY W-NW WINDS. SOME WIND GUSTS...ESP IN AREAS OF CHANNELED FLOW SUCH AS THE MOHAWK VALLEY/CAPITAL REGION...COULD REACH UP TO 25 MPH. THIS WILL MAKE FOR A COLD AND BLUSTERY AFTERNOON...ESP FROM THE CAPITAL REGION ON NORTH. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... IN THE WAKE OF THE FRONT...850 HPA TEMPS PLUNGE TO -16 TO -21 DEGREES C ACROSS THE REGION. THIS WILL RESULT IN VERY COLD TEMPERATURES TONIGHT. AS WINDS BECOME LIGHT...THE EXISTING SNOW PACK WILL AID IN ALLOWING FOR COLD MIN TEMPS...WITH SINGLE DIGITS TO TEENS FOR AREAS FROM THE MOHAWK VALLEY/CAPITAL REGION SOUTHWARD. NORTHERN AREAS LOOK TO BE VERY COLD...WITH READINGS BELOW ZERO ACROSS THE ADIRONDACKS/LAKE GEORGE/GLENS FALLS AREA AND GREEN MTNS OF SRN VT. SOME PORTIONS OF THE CENTRAL ADKS MAY DROP -10 TO -20 DEGREES F. WIND SPEEDS SHOULD DROP TO 5 MPH OR LESS DURING THE COLDEST PERIODS ACROSS THE ADIRONDACKS SO NO WIND CHILL ADVISORIES WILL BE ISSUED. HOWEVER...THESE COLD AMBIENT TEMPS WILL STILL BE HAZARDOUS ENOUGH TO CAUSE FROSTBITE QUICKLY...SO BE SURE TO TAKE EXTREME CAUTION IF YOU PLAN ON BEING IN THE BACK COUNTRY DURING THE OVERNIGHT HOURS. DESPITE THE COLD TEMPS...IT WON/T BE COMPLETELY CLEAR TONIGHT DUE TO THE UPPER TROUGH PASSING OVERHEAD AND SOME PASSING CLOUDS WILL BE AROUND. HOWEVER...NO SNOW SHOWERS ARE EXPECTED...ALTHOUGH SOME ICE CRYSTALS /DIAMOND DUST/ ARE POSSIBLE ACROSS THE ADIRONDACKS DUE TO THE COLD TEMPS. ON FRIDAY...A FEW LAKE EFFECT FLURRIES ARE POSSIBLE FOR FAR WESTERN AREAS...BUT THE SHEAR ISN/T FAVORABLE FOR MUCH LAKE EFFECT TO OCCUR. LITTLE TO NO SNOW ACCUMULATION IS EXPECTED FOR OUR AREA. OTHERWISE...IT LOOKS TO REMAIN DRY WITH PARTLY TO MOSTLY SUNNY SKIES. WARM AIR ADVECTION WILL BEGIN TO TAKE PLACE BY LATE IN THE DAY AS A WARM FRONT STARTS TO MOVE NORTH FROM THE SOUTH. MAX TEMPS ON FRIDAY WILL BE COLD WITH TEENS AND 20S ACROSS THE AREA. SOUTHERLY WINDS...AND WARMING TEMPS ALOFT...WILL ALLOW FOR FRI NIGHT TO NOT BE AS COLD AS TONIGHT. IT WILL ONLY DROP A FEW DEGREES FROM FRIDAY/S HIGHS ACROSS THE AREA...AND TEMPS MAY EVEN HOLD STEADY OR RISE AT TIMES. BY SATURDAY...THE REGION WILL BE BACK IN A WARM SECTOR...AND ABOVE NORMAL TEMPS WILL RETURN...WITH 30S TO LOW 40S ACROSS THE REGION. A CLIPPER SYSTEM WILL PASS ACROSS SOUTHERN CANADA...AND IT MAY BE CLOSE ENOUGH TO BRING SOME LIGHT SNOW TO THE ADIRONDACKS...ALTHOUGH THE BEST ACTIVITY LOOKS TO STAY NORTH OF THE US/CANADIAN BORDER. OTHERWISE...SKIES WILL BE PARTLY TO MOSTLY CLOUDY. ANOTHER ARCTIC FRONT WILL START TO APPROACH THE AREA FOR SATURDAY NIGHT. THE REGION SHOULD REMAIN OUT AHEAD OF IT THROUGH THE OVERNIGHT HOURS...SO TEMPS SAT NIGHT WON/T BE COLD YET /MAINLY 20S/. SOME SNOW SHOWERS MAY AFFECT MAINLY WESTERN PARTS OF THE REGION...ESP FOR THE LATE NIGHT HOURS. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... LOOKING AT A PERIOD OF BELOW NORMAL TEMPERATURES... NORMAL TEMPERATURES FOR THE PERIOD JAN 20TH THROUGH 23RD: ALBANY: HIGHS AROUND 30. LOWS IN THE MID TEENS. GLENS FALLS: HIGHS IN THE UPPER 20S. LOWS IN THE SINGLE DIGITS. POUGHKEEPSIE: HIGHS IN THE MID 30S. LOWS IN THE MID TEENS. BENNINGTON: HIGHS AROUND 30. LOWS NEAR 10. PITTSFIELD: HIGHS IN THE UPPER 20S. LOWS NEAR 10. MODEL GUIDANCE IS IN AGREEMENT IN REGARDS TO THE LONGWAVE PATTERN FOR THE PERIOD WITH A LARGE TROUGH COVERING THE EASTERN 2/3 OF THE CONUS WITH SHORT WAVES ROTATING ABOUT AN UPPER LOW OVER HUDSON BAY CANADA AND RIDGING ALONG THE WEST COAST. THE DIFFERENCES IN THE MODELS ARE WITH THE TIMING OF THE SHORT WAVES AND ASSOCIATED FRONTAL BOUNDARIES CROSSING THE REGION. AN ARCTIC FRONT WILL CROSS THE REGION SUNDAY. THIS FRONT WILL HAVE SOME DECENT UPPER LEVEL DYNAMICS AND A SHARP THERMAL GRADIENT ASSOCIATED WITH IT...SO A ROUND OF SNOW SHOWERS/SQUALLS IS POSSIBLE WITH THE FRONTAL PASSAGE. WINDS WILL SHIFT WEST-NORTHWEST AND BECOME BRISK AND GUSTY IN ITS WAKE AND TEMPERATURES SHOULD DROP DURING THE AFTERNOON. IT WILL GET COLD SUNDAY NIGHT WITH 850 MB TEMPERATURES DROPPING TO -15 TO -20 C ACROSS THE FORECAST AREA. WESTERLY WINDS OF 10 TO 20 MPH WILL MAKE IT FEEL EVEN COLDER. WIND CHILL VALUES MAY REACH ADVISORY CRITERIA (-20F) ACROSS THE SOUTHERN ADIRONDACKS...HAVE MENTION IN OUR HAZARDOUS WEATHER OUTLOOK. SHORT WAVES ROTATING ABOUT THE UPPER LOW WILL BRING REINFORCING SHOTS OF COLDER AIR TO THE REGION AS CLIPPER SYSTEMS MOVE THROUGH. THIS WILL KEEP CLOUDS AND THE THREAT OF SNOW SHOWERS IN THE FORECAST. THE SYSTEMS WILL HAVE LIMITED MOISTURE ASSOCIATED WITH THEM SO ANY PRECIPITATION/SNOW SHOULD BE LIGHT. HIGHS AND LOWS MONDAY THROUGH WEDNESDAY WILL BE SIMILAR EACH DAY AND NIGHT RUNNING AROUND 5 TO 10 DEGREES BELOW NORMAL. THE DIFFERENCE WILL BE THE WINDS AND HOW COLD IT FEELS. WIND CHILL COULD BE AN ISSUE AGAIN MONDAY NIGHT INTO TUESDAY MORNING ACROSS THE SOUTHERN ADIRONDACKS...HAVE MENTION IN OUR HAZARDOUS WEATHER OUTLOOK. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... LOW STRATUS CLOUDS FINALLY BROKE UP AT KGFL. VFR CONDITIONS ARE NOW EXPECTED THROUGH 12Z/FRIDAY. ARCTIC COLD FRONT MOVING INTO NEW YORK STATE...ON THE DOOR STEP TO THE FORECAST AREA. BOUNDARY WILL MOVE ACROSS THE AREA TODAY. SOUTH TO SOUTHWEST WINDS WILL SHIFT TO THE WEST WITH THE FRONTAL PASSAGE AND INCREASE IN SPEED WITH GUSTY CONDITIONS AT KALB AND KPSF. WINDS WILL SHIFT MORE TO THE NORTHWEST AND NORTH THIS EVENING AND WEAKEN. OUTLOOK... FRI-SAT...VFR...NO SIG WX. SUN...MAINLY VFR. CHC -SHSN. MON...VFR. SLIGHT CHC -SHSN. && .HYDROLOGY... MAINLY DRY AND COLD WEATHER WILL OCCUR OVER THE NEXT FIVE DAYS. WHILE SOME SNOW SHOWERS ARE POSSIBLE OVER THE NEXT FEW DAYS ACROSS NORTHERN AREAS...PRECIPITATION AMOUNTS WILL BE LIGHT AND IN THE FORM OF SNOW. COLD TEMPERATURES...ESPECIALLY EARLY NEXT WEEK...WILL CAUSE RIVER AND LAKE ICE TO FORM AND THICKEN. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS/HWJIV NEAR TERM...FRUGIS/HWJIV SHORT TERM...FRUGIS LONG TERM...IAA AVIATION...IAA HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
638 AM EST THU JAN 17 2013 .SYNOPSIS... AN ARCTIC COLD FRONT WILL CROSS THE REGION TODAY. THIS FRONT WILL BRING SOME SNOW SHOWERS TO THE ADIRONDACKS FOR THIS MORNING AS WELL AS ALLOWING MUCH COLDER AND BLUSTERY WEATHER INTO THE REGION FOR TONIGHT AND TOMORROW. A WARM FRONT WILL ALLOW TEMPERATURES TO RETURN ABOVE NORMAL AGAIN BRIEFLY FOR SATURDAY BEFORE ANOTHER STRONG COLD FRONT RETURNS COLD WEATHER TO THE AREA FOR SUNDAY INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 638 AM EST...SATELLITE AND SURFACE OBS SHOW AN ARCTIC COLD FRONT CROSSING NORTHERN AND WESTERN NEW YORK. AHEAD OF THIS BOUNDARY...THE COMBINATION OF SOME LAKE MOISTURE...LARGE SCALE LIFT FROM THE COLD FRONT AND UPSLOPE FLOW IS ALLOWING FOR SOME SNOW SHOWERS ACROSS THE WESTERN ADIRONDACKS...MAINLY ACROSS NORTHERN HERKIMER COUNTY. LIGHT SNOW ACCUMULATION OF AN INCH OR LESS IS POSSIBLE ACROSS THE WESTERN ADIRONDACKS. THE BOUNDARY SHOULD CROSS THE ADIRONDACK REGION BY THE MID MORNING HOURS. AS THIS BOUNDARY CONTINUES TO MOVE ACROSS THE REGION...SNOW SHOWERS WILL BECOME MORE ISOLD. 00Z NAM12 GUIDANCE...AS WELL AS THE LOCAL HIRES WRF AND THE 3KM HRRR GUIDANCE ALL SHOW THIS BAND OF SNOW SHOWERS FALLING APART AS IT REACHES THE MOHAWK VALLEY/SARATOGA AREA/SRN VT/CAPITAL REGION AROUND NOON DUE TO LITTLE MOISTURE AVAILABLE...SO WILL ONLY GO WITH SLIGHT CHC POPS OUTSIDE THE ADIRONDACKS. WHILE THERE MAY BE A FEW FLURRIES FOR THESE VALLEY AREAS LATE THIS MORNING/EARLY THIS AFTN...NO SNOW ACCUMULATION IS ANTICIPATED. THE FRONT WILL THEN CONTINUE SOUTHEAST ACROSS THE CATSKILLS/MID HUDSON VALLEY/BERKSHIRES/NW CT FOR THIS AFTN...BUT WITH NO PRECIP ASSOCIATED WITH IT. THE MAIN IMPACT WITH THIS FRONT WILL BE THE SHARP TEMPERATURE GRADIENT. MAX TEMPS WILL OCCUR AHEAD OF THE FRONT...WITH TEMPS RANGING FROM NEAR 20 IN THE ADIRONDACKS TO NEAR 40 IN THE MID HUDSON VALLEY. ONCE THE FRONT MOVES THROUGH...TEMPS WILL RAPIDLY FALL...ALONG WITH GUSTY W-NW WINDS. SOME WIND GUSTS...ESP IN AREAS OF CHANNELED FLOW SUCH AS THE MOHAWK VALLEY/CAPITAL REGION...COULD REACH UP TO 25 MPH. THIS WILL MAKE FOR A COLD AND BLUSTERY AFTERNOON...ESP FROM THE CAPITAL REGION ON NORTH. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... IN THE WAKE OF THE FRONT...850 HPA TEMPS PLUNGE TO -16 TO -21 DEGREES C ACROSS THE REGION. THIS WILL RESULT IN VERY COLD TEMPERATURES TONIGHT. AS WINDS BECOME LIGHT...THE EXISTING SNOW PACK WILL AID IN ALLOWING FOR COLD MIN TEMPS...WITH SINGLE DIGITS TO TEENS FOR AREAS FROM THE MOHAWK VALLEY/CAPITAL REGION SOUTHWARD. NORTHERN AREAS LOOK TO BE VERY COLD...WITH READINGS BELOW ZERO ACROSS THE ADIRONDACKS/LAKE GEORGE/GLENS FALLS AREA AND GREEN MTNS OF SRN VT. SOME PORTIONS OF THE CENTRAL ADKS MAY DROP -10 TO -20 DEGREES F. WIND SPEEDS SHOULD DROP TO 5 MPH OR LESS DURING THE COLDEST PERIODS ACROSS THE ADIRONDACKS SO NO WIND CHILL ADVISORIES WILL BE ISSUED. HOWEVER...THESE COLD AMBIENT TEMPS WILL STILL BE HAZARDOUS ENOUGH TO CAUSE FROSTBITE QUICKLY...SO BE SURE TO TAKE EXTREME CAUTION IF YOU PLAN ON BEING IN THE BACK COUNTRY DURING THE OVERNIGHT HOURS. DESPITE THE COLD TEMPS...IT WON/T BE COMPLETELY CLEAR TONIGHT DUE TO THE UPPER TROUGH PASSING OVERHEAD AND SOME PASSING CLOUDS WILL BE AROUND. HOWEVER...NO SNOW SHOWERS ARE EXPECTED...ALTHOUGH SOME ICE CRYSTALS /DIAMOND DUST/ ARE POSSIBLE ACROSS THE ADIRONDACKS DUE TO THE COLD TEMPS. ON FRIDAY...A FEW LAKE EFFECT FLURRIES ARE POSSIBLE FOR FAR WESTERN AREAS...BUT THE SHEAR ISN/T FAVORABLE FOR MUCH LAKE EFFECT TO OCCUR. LITTLE TO NO SNOW ACCUMULATION IS EXPECTED FOR OUR AREA. OTHERWISE...IT LOOKS TO REMAIN DRY WITH PARTLY TO MOSTLY SUNNY SKIES. WARM AIR ADVECTION WILL BEGIN TO TAKE PLACE BY LATE IN THE DAY AS A WARM FRONT STARTS TO MOVE NORTH FROM THE SOUTH. MAX TEMPS ON FRIDAY WILL BE COLD WITH TEENS AND 20S ACROSS THE AREA. SOUTHERLY WINDS...AND WARMING TEMPS ALOFT...WILL ALLOW FOR FRI NIGHT TO NOT BE AS COLD AS TONIGHT. IT WILL ONLY DROP A FEW DEGREES FROM FRIDAY/S HIGHS ACROSS THE AREA...AND TEMPS MAY EVEN HOLD STEADY OR RISE AT TIMES. BY SATURDAY...THE REGION WILL BE BACK IN A WARM SECTOR...AND ABOVE NORMAL TEMPS WILL RETURN...WITH 30S TO LOW 40S ACROSS THE REGION. A CLIPPER SYSTEM WILL PASS ACROSS SOUTHERN CANADA...AND IT MAY BE CLOSE ENOUGH TO BRING SOME LIGHT SNOW TO THE ADIRONDACKS...ALTHOUGH THE BEST ACTIVITY LOOKS TO STAY NORTH OF THE US/CANADIAN BORDER. OTHERWISE...SKIES WILL BE PARTLY TO MOSTLY CLOUDY. ANOTHER ARCTIC FRONT WILL START TO APPROACH THE AREA FOR SATURDAY NIGHT. THE REGION SHOULD REMAIN OUT AHEAD OF IT THROUGH THE OVERNIGHT HOURS...SO TEMPS SAT NIGHT WON/T BE COLD YET /MAINLY 20S/. SOME SNOW SHOWERS MAY AFFECT MAINLY WESTERN PARTS OF THE REGION...ESP FOR THE LATE NIGHT HOURS. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... ...LOOKING AT A PERIOD OF BELOW NORMAL TEMPERATURES... NORMAL TEMPERATURES FOR THE PERIOD JAN 20TH THROUGH 23RD: ALBANY: HIGHS AROUND 30. LOWS IN THE MID TEENS. GLENS FALLS: HIGHS IN THE UPPER 20S. LOWS IN THE SINGLE DIGITS. POUGHKEEPSIE: HIGHS IN THE MID 30S. LOWS IN THE MID TEENS. BENNINGTON: HIGHS AROUND 30. LOWS NEAR 10. PITTSFIELD: HIGHS IN THE UPPER 20S. LOWS NEAR 10. MODEL GUIDANCE IS IN AGREEMENT IN REGARDS TO THE LONGWAVE PATTERN FOR THE PERIOD WITH A LARGE TROUGH COVERING THE EASTERN 2/3 OF THE CONUS WITH SHORT WAVES ROTATING ABOUT AN UPPER LOW OVER HUDSONS BAY CANADA AND RIDGING ALONG THE WEST COAST. THE DIFFERENCES IN THE MODELS ARE WITH THE TIMING OF THE SHORT WAVES AND ASSOCIATED FRONTAL BOUNDARIES CROSSING THE REGION. AN ARCTIC FRONT WILL CROSS THE REGION SUNDAY. THIS FRONT WILL HAVE SOME DECENT UPPER LEVEL DYNAMICS AND A SHARP THERMAL GRADIENT ASSOCIATED WITH IT...SO A ROUND OF SNOW SHOWERS/SQUALLS IS POSSIBLE WITH THE FRONTAL PASSAGE. WINDS WILL SHIFT WEST-NORTHWEST AND BECOME BRISK AND GUSTY IN ITS WAKE AND TEMPERATURES SHOULD DROP DURING THE AFTERNOON. IT WILL GET COLD SUNDAY NIGHT WITH 850 MB TEMPERATURES DROPPING TO -15 TO -20 C ACROSS THE FORECAST AREA. WESTERLY WINDS OF 10 TO 20 MPH WILL MAKE IT FEEL EVEN COLDER. WIND CHILL VALUES MAY REACH ADVISORY CRITERIA (-20F) ACROSS THE SOUTHERN ADIRONDACKS...HAVE MENTION IN OUR HAZARDOUS WEATHER OUTLOOK. SHORT WAVES ROTATING ABOUT THE UPPER LOW WILL BRING REINFORCING SHOTS OF COLDER AIR TO THE REGION AS CLIPPER SYSTEMS MOVE THROUGH. THIS WILL KEEP CLOUDS AND THE THREAT OF SNOW SHOWERS IN THE FORECAST. THE SYSTEMS WILL HAVE LIMITED MOISTURE ASSOCIATED WITH THEM SO ANY PRECIPITATION/SNOW SHOULD BE LIGHT. HIGHS AND LOWS MONDAY THROUGH WEDNESDAY WILL BE SIMILAR EACH DAY AND NIGHT RUNNING AROUND 5 TO 10 DEGREES BELOW NORMAL. THE DIFFERENCE WILL BE THE WINDS AND HOW COLD IT FEELS. WIND CHILL COULD BE AN ISSUE AGAIN MONDAY NIGHT INTO TUESDAY MORNING ACROSS THE SOUTHERN ADIRONDACKS...HAVE MENTION IN OUR HAZARDOUS WEATHER OUTLOOK. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... LOW STRATUS CLOUDS FINALLY BROKE UP AT KGFL. VFR CONDITIONS ARE NOW EXPECTED THROUGH 12Z/FRIDAY. ARCTIC COLD FRONT MOVING INTO NEW YORK STATE...ON THE DOOR STEP TO THE FORECAST AREA. BOUNDARY WILL MOVE ACROSS THE AREA TODAY. SOUTH TO SOUTHWEST WINDS WILL SHIFT TO THE WEST WITH THE FRONTAL PASSAGE AND INCREASE IN SPEED WITH GUSTY CONDITIONS AT KALB AND KPSF. WINDS WILL SHIFT MORE TO THE NORTHWEST AND NORTH THIS EVENING AND WEAKEN. OUTLOOK... FRI-SAT...VFR...NO SIG WX. SUN...MAINLY VFR. CHC -SHSN. MON...VFR. SLIGHT CHC -SHSN. && .HYDROLOGY... MAINLY DRY AND COLD WEATHER WILL OCCUR OVER THE NEXT FIVE DAYS. WHILE SOME SNOW SHOWERS ARE POSSIBLE OVER THE NEXT FEW DAYS ACROSS NORTHERN AREAS...PRECIPITATION AMOUNTS WILL BE LIGHT AND IN THE FORM OF SNOW. COLD TEMPERATURES...ESPECIALLY EARLY NEXT WEEK...WILL CAUSE RIVER AND LAKE ICE TO FORM AND THICKEN. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS NEAR TERM...FRUGIS SHORT TERM...FRUGIS LONG TERM...IAA AVIATION...IAA HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
905 PM CST FRI JAN 18 2013 .DISCUSSION... 240 PM CST A VERY ACTIVE WEATHER PATTERN WILL PERSIST FOR THE NEXT SEVERAL DAYS. WHILE THE WEATHER PATTERN WILL BE A BIT OF A ROLLER COASTER RIDE...THE MAIN ISSUES WILL FOCUS ON TEMPERATURES...WITH STILL...LITTLE OPPORTUNITY FOR ANY SIGNIFICANT PRECIPITATION. FOR THE REMAINDER OF THE AFTERNOON AND THIS EVENING...THE MAIN FORECAST CONCERN WILL FOCUS ON THE ONGOING STRONG WINDS. LATEST TAMDAR SOUNDINGS INDICATE WINDS UP TO 50KT AT THE TOP OF THE MIXED LAYER...BUT THESE STRONGEST WINDS HAVE NOT BEEN ABLE TO MIX DOWN TO THE SURFACE. THE LATEST SFC OBS ACROSS THE REGION INDICATE WIDESPREAD GUSTS OF 30-35KT ACROSS THE AREA. WITH THE SUN ANGLE BEGINNING TO DECREASE THROUGH THE AFTERNOON AND NO ADDITIONAL SFC WARMING LIKELY...DO NOT EXPECT THAT WINDS WILL GET ANY HIGHER THAN CURRENTLY OCCURRING...AND SHOULD BEGIN TO DROP OFF AT SUNSET. ALSO...WITH THE FIRST IN A SERIES OF SFC LOW TRACKING THROUGH NRN WI AND NRN LAKE MICHIGAN...COMBINED WITH STRONG HIGH PRESSURE OVER THE MID ATLANTIC REGION...A STRONG SWLY PRESSURE GRADIENT WILL REMAIN IN PLACE THROUGH THE NIGHT. THIS WILL HAVE A TWO-FOLD IMPACT. FIRST...WINDS WILL REMAIN RATHER BREEZY THROUGH THE NIGHT AND THE PERSISTENT WARM ADVECTION WILL ALLOW MAX TEMPS TO PEAK IN THE LOWER...TO PERHAPS MIDDLE...40S. SECOND...OVERNIGHT LOWS TONIGHT WILL NOT BE QUITE AS LOW AS RECENT DAYS...WITH TEMPS BOTTOMING OUT IN THE LOWER TO MIDDLE 30S. SATURDAY SHOULD REMAIN ON THE WARMER SIDE AS A SECOND LOW DROPS OUT OF THE CANADIAN ROCKIES TONIGHT AND TAKES A SIMILAR TRACK ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY TOMORROW MORNING AND THE NORTHERN GREAT LAKES TOMORROW AFTERNOON. CONDITIONS WILL BE BREEZY AND UNSEASONABLY WARM AGAIN ON SATURDAY...BUT DO NOT EXPECT WINDS TO BE QUITE AS STRONG AS THE TRACK OF THE LOW WILL BE A LITTLE FARTHER NORTH...ACROSS THE UPPER PENINSULA OF MICHIGAN WHILE THE CENTER OF THE HIGH SAGS SWD INTO THE CAROLINAS. A SIGNIFICANT CHANGE IN AIR MASS CHARACTER WILL COMMENCE AS THE LOW DRAGS AN ARCTIC COLD FRONT ACROSS THE REGION...USHERING IN MUCH COOLER AIR WITH AN EXTENDED PERIOD OF COLD ADVECTION...WHICH WILL PERSIST INTO EARLY NEXT WEEK. THE TEMPERATURE DROP OFF WILL QUITE DRAMATIC WITH HIGHS ON SUNDAY EXPECTED TO BE AROUND 25 DEGREES LOWER THAN SATURDAY...RANGING FROM THE UPPER TEENS ALONG THE WISCONSIN BORDER TO THE MIDDLE 20S SOUTH OF THE KANKAKEE/ILLINOIS RIVERS. THE TRUE ARCTIC AIR MASS WILL ARRIVE OVERNIGHT SUNDAY NIGH AND MONDAY AS STRONG HIGH PRESSURE BUILDS DOWN OUT OF CANADA...SPREADING ACROSS THE NRN PLAINS AND THE MISSISSIPPI VALLEY. BY MONDAY MORNING...EXPECT LOW TEMPERATURES SHOULD BE IN THE SINGLE DIGITS RIGHT UP THE LAKE MICHIGAN SHORELINE AND EVEN DOWNTOWN CHICAGO WILL NOT ESCAPE THE COLD AS NORTHWESTERLY WINDS WILL NOT ALLOW ANY WARMING EFFECT OF THE ADJACENT LAKE MICHIGAN WATERS. THE ONLY PART OF THE AREA NOT EXPECTED TO SEE TEMPS DROP INTO THE SINGLE DIGITS WILL BE NRN PORTER COUNTY...WHERE THE NWLY FLOW MAY ALLOW FOR SOME LAKE EFFECT CLOUD COVER. WITH THE PERSISTENT COLD ADVECTION AND THE CENTER OF THE ARCTIC HIGH EXPECTED TO MOVE ACROSS IL/WI...THERE WILL BE LITTLE DIURNAL TEMPERATURE VARIATION THROUGH THE DAY ON MONDAY. EVEN WITH SOME SUNSHINE UNDER PARTLY CLOUDY SKIES...TEMPERATURES SHOULD ONLY CLIMB A FEW DEGREES THROUGH THE DAY...TOPPING OUT IN THE SINGLE DIGITS IN NRN IL...INCLUDING THE ROCKFORD METRO AREA...WHILE THE REST OF THE CWA WILL SEE HIGHS IN THE LOWER TEENS. TUESDAY MORNING WILL BE THE COLDEST SEEN IN QUITE SOME TIME AS LIGHT WINDS AND LIMITED CLOUD COVER WILL ALLOW FOR SIGNIFICANT RADIATIVE COOLING WITH LOWS DROPPING TO NEAR OR SLIGHTLY BELOW 0F. QUITE A FEAT CONSIDERING THE LAKE OF SNOW COVER. WITH THE HIGH REMAINING OVER THE REGION...HIGHS ON TUESDAY WILL BE LITTLE DIFFERENT FROM THOSE SEEN ON MONDAY. FOR THE EXTENDED FORECAST PERIOD...FROM WEDNESDAY INTO SATURDAY...A RAPID WARMING TREND WILL OCCUR AS LOW LEVEL FLOW QUICKLY RETURNS TO SOUTHERLY IN ADVANCE OF A WEAK CLIPPER-TYPE SYSTEM DROPPING ACROSS THE NORTHERN PLAINS AND A SOUTHERN STREAM SYSTEM DEVELOPING OVER THE CENTRAL PLAINS. GIVEN THE CONTINUED LACK OF SNOW COVER TO MODIFY THE AIR MASS DRAWN ACROSS THE AREA IN THE SWLY FLOW AHEAD OF THE SRN STREAM SYSTEM...EXPECT THAT TEMPERATURES SHOULD BE ABLE TO CLIMB BACK INTO THE UPPER 30S TO LOWER 40S BY THURSDAY. UNFORTUNATELY...SIGNIFICANT MODEL DIFFERENCES DEVELOP BY THIS TIME RANGE BETWEEN THE GFS AND THE ECMWF. THE GFS IS ADVERTISING NO PHASING OF THE NRN AND SRN STREAM SYSTEMS...WITH THE SRN STREAM SYSTEM RACING OUT AHEAD OF THE CLIPPER. THE ECMWF IS SIGNIFICANTLY DIFFERENT...PHASING THE TWO SYSTEM INTO A SINGLE LOW...TRACKING ACROSS CENTRAL ILLINOIS THURSDAY NIGHT AND QUICKLY TRACKING INTO SWRN PA BY FRIDAY MORNING. THE GFS FINALLY INDICATES SOME PHASING OF THE TWO SYSTEMS...BUT NOT UNTIL THEY PUSH EAST OF THE AREA ON FRIDAY. THESE DIFFERENT SCENARIOS SHOULD HAVE A SIGNIFICANT IMPACT ON THE LOCAL WEATHER. THE SLOWER GFS WOULD ALLOW FOR WARMER CONDITIONS AND A GREATER CHANCE FOR ANY ASSOCIATED PCPN TO LESS LIKELY BE SNOW...WHILE THE FASTER ECMWF WOULD SUGGEST A COOLER FORECAST WITH A GREATER CHANCE FOR AT LEAST SOME SNOW. GIVEN THE FAIR AMOUNT OF UNCERTAINTY BUT WITH A HISTORY OF WARMER CONDITIONS THIS WINTER...HAVE TRENDED CLOSER TO THE WARMER SOLUTION. WHILE EITHER SOLUTION WOULD SUGGEST A SIGNIFICANT CHANCE FOR PRECIPITATION FOR THURSDAY INTO FRIDAY...FEEL THAT THERE SHOULD BE A PERIOD OF RAIN LATE THURSDAY...WITH A CHANCE FOR SOME LIGHT SNOW EARLY THURSDAY AND THEN LATER THURSDAY NIGHT. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * SSW WIND GUSTING 20-25KT REST OF THIS EVENING AND INTO OVERNIGHT. * SW WIND GUSTING 22-27KT MID MORNING THROUGH AFTERNOON SAT. * STRONG GOLD FRONT PASSAGE DURING EARLY EVENING SAT WITH W-WNW WIND GUSTING 30-35KT. TRS //DISCUSSION...UPDATED 03Z... SW WINDS OF 50-60KT CONTINUE TO BE SEEN IN VAD WINDS AND AIRCRAFT REPORTS SO HAVE EXTENDED INCLUSION OF LLWS IN TAFORS THROUGH THE NIGHT...THOUGH HAVE SPEED GRADUALLY DECREASING TO 40KT WITH TIME PER LATEST RAP HOURLY WIND PROGS. PREVIOUS DISCUSSION...UPDATED 00Z... WITH SUNDOWN...A LESSENING OF THE PRESSURE GRADIENT OVER THE AREA AND THE PRESSURE FALL CENTER MOVING E TO THE CENTRAL GREAT LAKES WINDS HAVE DIMINISHED SOMEWHAT EARLY THIS EVENING. A SLOW DIMINISHING OF SURFACE WIND SPEED IS EXPECTED TO CONTINUE TONIGHT. WHILE SURFACE WINDS ARE DROPPING OFF WINDS WITHIN 2K FT AGL ARE 45-50KT PER VAD WIND PROFILES FROM KLOT AND TORD RADARS VERIFYING RAP MODEL WIND FORECAST. LATEST RAP RUN FROM 22Z HAS SW WINDS JUST ABOVE THE SURFACE GRADUALLY DIMINISHING THROUGH THE NIGHT. HAVE LLWS DROPPED FROM THE TAFORS AT 05Z THOUGH MAY NEED TO EXTEND IT A BIT FURTHER INTO THE OVERNIGHT IF LOW LEVEL WINDS DO NOT DROP OFF QUITE THAT QUICKLY. PRESSURE GRADIENT WILL INCREASE AGAIN SAT AS ANOTHER LOW DEEPENS AS IT MOVES FROM NW MN ESE TO EASTERN LAKE SUPERIOR DURING THE DAY. SW SURFACE WIND SAT NOT EXPECTED TO BE AS STRONG AS THIS AFTERNOON BUT ARE EXPECTED TO BE GUSTING IN THE MID TO UPPER 20KT RANGE BY MIDDAY. A STRONG COLD FRONT TRAILING SW FROM THE LOW IS PROGGED TO ADVANCE TO ACROSS W CENTRAL LOWER MI...FAR NE IL AND E CENTRAL IA BY 20.00Z AND TO THEN MOVE ACROSS ORD AND MDW DURING THE EARLY EVENING SHIFTING WINDS FROM WSW TO WNW AND GUST 30-35KT AS A STRONG PRESSURE RISE CENTER MOVES SE TOWARD THE LOCAL AREA AS ARCTIC AIR SPILLS FURTHER SOUTHEASTWARD FROM THE UPPER MIDWEST. TRS //ORD AND MDW CONFIDENCE...UPDATED 03Z... * HIGH CONFIDENCE ALL ELEMENTS...EXCEPT MODERATE CONFIDENCE IN WIND SPEED FROM SAT MID-MORNING THROUGH AFTERNOON. TRS //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...MVFR CEILINGS. MONDAY...VFR. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...VFR. CHANCE OF SN RESULTING IN MVFR CONDITIONS. TRS && .MARINE... 237 PM CST HIGH PRESSURE REMAINS FROM THE LOWER MISSISSIPPI RIVER VALLEY NORTHEASTWARD ACROSS THE OHIO VALLEY AND MID ATLANTIC THIS AFTERNOON WHILE AND ELONGATED AREA OF LOW PRESSURE IS SPREAD FROM CENTRAL ALBERTA TO LAKE MICHIGAN. A LOW PRESSURE CIRCULATION EMBEDDED WITHIN THE TROUGH IS PUSHING FROM WESTERN WISCONSIN EASTWARD WITH VERY STRONG PRESSURE FALLS OVER LAKE MICHIGAN THANKS TO THE DIFFERENCE IN PRESSURE BETWEEN IT AND THE HIGH TO THE SOUTHEAST. SOUTHWEST GALES CONTINUE ACROSS THE SOUTHERN TWO-THIRDS OR SO OF THE LAKE WITH THE FAR NORTH IN THE TROUGH AXIS RESULTING IN LIGHTER WINDS. THE LOW WILL CROSS THE LAKE THIS EVENING ALLOWING WINDS TO EASE FROM NORTHWEST TO SOUTHEAST THROUGH THE EVENING. NORTH-CENTRAL SECTIONS OF THE LAKE SHOULD SEE WINDS EASE THIS EVENING WITH IT TAKING UNTIL AROUND MIDNIGHT OR SOON AFTER FOR GALES TO DIMINISH SOUTH. WILL LET THE GALE WARNING GO AS-IS FOR NOW BUT IT MAY BE ABLE TO BE CANCELLED EARLY NORTH. FOR THE NEARSHORE WATERS...WILL END THE ILLINOIS SHORES A BIT EARLIER BUT CARRY THE INDIANA SHORELINE UNTIL 09Z AS SCHEDULED BUT IT IS POSSIBLE THIS MAY NEED TO BE SHORTENED. EXPECT THAT A SMALL CRAFT ADVISORY WILL BE NEEDED ONCE GALES DIMINISH. A SECOND LOW WILL DEEPEN ACROSS SASKATCHEWAN TONIGHT AND MOVE TO WESTERN LAKE SUPERIOR BY SATURDAY AFTERNOON. THE LOW WILL THEN FURTHER DEEPEN AS IT CROSSES THE U.P. OF MICHIGAN SATURDAY EVENING AND HEADS TOWARD SOUTHERN QUEBEC BY SUNDAY MORNING. SOUTH TO SOUTHWEST WINDS WILL INTENSIFY SATURDAY WITH LOWER END GALES EXPECTED TO BEGIN DURING THE EARLY AFTERNOON ACROSS THE OPEN WATERS...WITH NEARSHORE AREAS LIKELY HOLDING INTO THE UPPER 20S TO ABOUT 30 KT. WILL PUSH THE START TIME OF THE GALE WATCH FOR THE NEARSHORE WATERS LATER TO 00Z BUT UPGRADE TO A GALE WARNING FOR THE OPEN WATERS FROM 18Z ON WITH THE NORTHERN TWO-THIRDS EXPECTED TO SEE GALES DURING THE AFTERNOON. WINDS WILL TURN WESTERLY THEN NORTHWESTERLY SATURDAY EVENING AS THE LOW AND A COLD FRONT PASS WITH MUCH COLDER AIR ARRIVING. THE COMBINATION OF COLD ADVECTION AND THE DEEPENING LOW PASSING NORTH OF THE LAKE WILL BE VERY FAVORABLE FOR HIGH END GALES ACROSS MUCH OF THE LAKE SATURDAY EVENING AND EARLY SATURDAY NIGHT BEFORE EASING SUNDAY MORNING. IT DOES APPEAR THAT A 3-6 HR PERIOD WILL BE FAVORABLE FOR A FEW STORM FORCE GUSTS TO 50 KT ROUGHLY BETWEEN 03 AND 06 OR 09Z ACROSS CENTRAL PORTIONS OF THE LAKE. WILL HIGHLIGHT THIS IN THE TEXT FOR NOW. WITH THE COLDER AIR...HEAVY FREEZING SPRAY IS ALSO A CONCERN LATE SATURDAY EVENING THROUGH SUNDAY MORNING AS AIR TEMPS FALL INTO THE MID/UPPER TEENS. WILL ISSUE A HEAVY FREEZING SPRAY WATCH FROM 06 TO 18Z SUNDAY. WINDS WILL EASE SUNDAY MORNING AS THE LOW DEPARTS BUT THE STEADY FLOW OF COLDER AIR AND A TIGHT PRESSURE GRADIENT WILL KEEP WINDS ELEVATED THROUGH EARLY NEXT WEEK AND MAY BE MODULATED UP AND DOWN BY PASSING WEAK LOWS. HIGH PRESSURE DOES LOOK TO EVENTUALLY ARRIVE OVER THE LAKE DURING THE MID OR LATE PART OF THE WEEK WHICH WOULD PROVIDE MUCH LIGHTER WINDS. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673- LMZ675-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM SATURDAY. GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON SATURDAY TO 9 AM SUNDAY. HEAVY FREEZING SPRAY WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366- LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...MIDNIGHT SUNDAY TO NOON SUNDAY. GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...6 PM SATURDAY TO 9 AM SUNDAY. GALE WARNING...ILLINOIS NEARSHORE WATERS UNTIL 10 PM FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
611 PM CST FRI JAN 18 2013 .DISCUSSION... 240 PM CST A VERY ACTIVE WEATHER PATTERN WILL PERSIST FOR THE NEXT SEVERAL DAYS. WHILE THE WEATHER PATTERN WILL BE A BIT OF A ROLLER COASTER RIDE...THE MAIN ISSUES WILL FOCUS ON TEMPERATURES...WITH STILL...LITTLE OPPORTUNITY FOR ANY SIGNIFICANT PRECIPITATION. FOR THE REMAINDER OF THE AFTERNOON AND THIS EVENING...THE MAIN FORECAST CONCERN WILL FOCUS ON THE ONGOING STRONG WINDS. LATEST TAMDAR SOUNDINGS INDICATE WINDS UP TO 50KT AT THE TOP OF THE MIXED LAYER...BUT THESE STRONGEST WINDS HAVE NOT BEEN ABLE TO MIX DOWN TO THE SURFACE. THE LATEST SFC OBS ACROSS THE REGION INDICATE WIDESPREAD GUSTS OF 30-35KT ACROSS THE AREA. WITH THE SUN ANGLE BEGINNING TO DECREASE THROUGH THE AFTERNOON AND NO ADDITIONAL SFC WARMING LIKELY...DO NOT EXPECT THAT WINDS WILL GET ANY HIGHER THAN CURRENTLY OCCURRING...AND SHOULD BEGIN TO DROP OFF AT SUNSET. ALSO...WITH THE FIRST IN A SERIES OF SFC LOW TRACKING THROUGH NRN WI AND NRN LAKE MICHIGAN...COMBINED WITH STRONG HIGH PRESSURE OVER THE MID ATLANTIC REGION...A STRONG SWLY PRESSURE GRADIENT WILL REMAIN IN PLACE THROUGH THE NIGHT. THIS WILL HAVE A TWO-FOLD IMPACT. FIRST...WINDS WILL REMAIN RATHER BREEZY THROUGH THE NIGHT AND THE PERSISTENT WARM ADVECTION WILL ALLOW MAX TEMPS TO PEAK IN THE LOWER...TO PERHAPS MIDDLE...40S. SECOND...OVERNIGHT LOWS TONIGHT WILL NOT BE QUITE AS LOW AS RECENT DAYS...WITH TEMPS BOTTOMING OUT IN THE LOWER TO MIDDLE 30S. SATURDAY SHOULD REMAIN ON THE WARMER SIDE AS A SECOND LOW DROPS OUT OF THE CANADIAN ROCKIES TONIGHT AND TAKES A SIMILAR TRACK ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY TOMORROW MORNING AND THE NORTHERN GREAT LAKES TOMORROW AFTERNOON. CONDITIONS WILL BE BREEZY AND UNSEASONABLY WARM AGAIN ON SATURDAY...BUT DO NOT EXPECT WINDS TO BE QUITE AS STRONG AS THE TRACK OF THE LOW WILL BE A LITTLE FARTHER NORTH...ACROSS THE UPPER PENINSULA OF MICHIGAN WHILE THE CENTER OF THE HIGH SAGS SWD INTO THE CAROLINAS. A SIGNIFICANT CHANGE IN AIR MASS CHARACTER WILL COMMENCE AS THE LOW DRAGS AN ARCTIC COLD FRONT ACROSS THE REGION...USHERING IN MUCH COOLER AIR WITH AN EXTENDED PERIOD OF COLD ADVECTION...WHICH WILL PERSIST INTO EARLY NEXT WEEK. THE TEMPERATURE DROP OFF WILL QUITE DRAMATIC WITH HIGHS ON SUNDAY EXPECTED TO BE AROUND 25 DEGREES LOWER THAN SATURDAY...RANGING FROM THE UPPER TEENS ALONG THE WISCONSIN BORDER TO THE MIDDLE 20S SOUTH OF THE KANKAKEE/ILLINOIS RIVERS. THE TRUE ARCTIC AIR MASS WILL ARRIVE OVERNIGHT SUNDAY NIGH AND MONDAY AS STRONG HIGH PRESSURE BUILDS DOWN OUT OF CANADA...SPREADING ACROSS THE NRN PLAINS AND THE MISSISSIPPI VALLEY. BY MONDAY MORNING...EXPECT LOW TEMPERATURES SHOULD BE IN THE SINGLE DIGITS RIGHT UP THE LAKE MICHIGAN SHORELINE AND EVEN DOWNTOWN CHICAGO WILL NOT ESCAPE THE COLD AS NORTHWESTERLY WINDS WILL NOT ALLOW ANY WARMING EFFECT OF THE ADJACENT LAKE MICHIGAN WATERS. THE ONLY PART OF THE AREA NOT EXPECTED TO SEE TEMPS DROP INTO THE SINGLE DIGITS WILL BE NRN PORTER COUNTY...WHERE THE NWLY FLOW MAY ALLOW FOR SOME LAKE EFFECT CLOUD COVER. WITH THE PERSISTENT COLD ADVECTION AND THE CENTER OF THE ARCTIC HIGH EXPECTED TO MOVE ACROSS IL/WI...THERE WILL BE LITTLE DIURNAL TEMPERATURE VARIATION THROUGH THE DAY ON MONDAY. EVEN WITH SOME SUNSHINE UNDER PARTLY CLOUDY SKIES...TEMPERATURES SHOULD ONLY CLIMB A FEW DEGREES THROUGH THE DAY...TOPPING OUT IN THE SINGLE DIGITS IN NRN IL...INCLUDING THE ROCKFORD METRO AREA...WHILE THE REST OF THE CWA WILL SEE HIGHS IN THE LOWER TEENS. TUESDAY MORNING WILL BE THE COLDEST SEEN IN QUITE SOME TIME AS LIGHT WINDS AND LIMITED CLOUD COVER WILL ALLOW FOR SIGNIFICANT RADIATIVE COOLING WITH LOWS DROPPING TO NEAR OR SLIGHTLY BELOW 0F. QUITE A FEAT CONSIDERING THE LAKE OF SNOW COVER. WITH THE HIGH REMAINING OVER THE REGION...HIGHS ON TUESDAY WILL BE LITTLE DIFFERENT FROM THOSE SEEN ON MONDAY. FOR THE EXTENDED FORECAST PERIOD...FROM WEDNESDAY INTO SATURDAY...A RAPID WARMING TREND WILL OCCUR AS LOW LEVEL FLOW QUICKLY RETURNS TO SOUTHERLY IN ADVANCE OF A WEAK CLIPPER-TYPE SYSTEM DROPPING ACROSS THE NORTHERN PLAINS AND A SOUTHERN STREAM SYSTEM DEVELOPING OVER THE CENTRAL PLAINS. GIVEN THE CONTINUED LACK OF SNOW COVER TO MODIFY THE AIR MASS DRAWN ACROSS THE AREA IN THE SWLY FLOW AHEAD OF THE SRN STREAM SYSTEM...EXPECT THAT TEMPERATURES SHOULD BE ABLE TO CLIMB BACK INTO THE UPPER 30S TO LOWER 40S BY THURSDAY. UNFORTUNATELY...SIGNIFICANT MODEL DIFFERENCES DEVELOP BY THIS TIME RANGE BETWEEN THE GFS AND THE ECMWF. THE GFS IS ADVERTISING NO PHASING OF THE NRN AND SRN STREAM SYSTEMS...WITH THE SRN STREAM SYSTEM RACING OUT AHEAD OF THE CLIPPER. THE ECMWF IS SIGNIFICANTLY DIFFERENT...PHASING THE TWO SYSTEM INTO A SINGLE LOW...TRACKING ACROSS CENTRAL ILLINOIS THURSDAY NIGHT AND QUICKLY TRACKING INTO SWRN PA BY FRIDAY MORNING. THE GFS FINALLY INDICATES SOME PHASING OF THE TWO SYSTEMS...BUT NOT UNTIL THEY PUSH EAST OF THE AREA ON FRIDAY. THESE DIFFERENT SCENARIOS SHOULD HAVE A SIGNIFICANT IMPACT ON THE LOCAL WEATHER. THE SLOWER GFS WOULD ALLOW FOR WARMER CONDITIONS AND A GREATER CHANCE FOR ANY ASSOCIATED PCPN TO LESS LIKELY BE SNOW...WHILE THE FASTER ECMWF WOULD SUGGEST A COOLER FORECAST WITH A GREATER CHANCE FOR AT LEAST SOME SNOW. GIVEN THE FAIR AMOUNT OF UNCERTAINTY BUT WITH A HISTORY OF WARMER CONDITIONS THIS WINTER...HAVE TRENDED CLOSER TO THE WARMER SOLUTION. WHILE EITHER SOLUTION WOULD SUGGEST A SIGNIFICANT CHANCE FOR PRECIPITATION FOR THURSDAY INTO FRIDAY...FEEL THAT THERE SHOULD BE A PERIOD OF RAIN LATE THURSDAY...WITH A CHANCE FOR SOME LIGHT SNOW EARLY THURSDAY AND THEN LATER THURSDAY NIGHT. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * SSW WIND GUSTING 20-25KT THROUGH THE THIS EVENING AND INTO OVERNIGHT. * SW WIND GUSTING 22-27KT MID MORNING THROUGH AFTERNOON SAT. * STRONG GOLD FRONT PASSAGE DURING EARLY EVENING SAT WITH W-WNW WIND GUSTING 30-35KT. TRS //DISCUSSION...UPDATED 00Z... WITH SUNDOWN...A LESSENING OF THE PRESSURE GRADIENT OVER THE AREA AND THE PRESSURE FALL CENTER MOVING E TO THE CENTRAL GREAT LAKES WINDS HAVE DIMINISHED SOMEWHAT EARLY THIS EVENING. A SLOW DIMINISHING OF SURFACE WIND SPEED IS EXPECTED TO CONTINUE TONIGHT. WHILE SURFACE WINDS ARE DROPPING OFF WINDS WITHIN 2K FT AGL ARE 45-50KT PER VAD WIND PROFILES FROM KLOT AND TORD RADARS VERIFYING RAP MODEL WIND FORECAST. LATEST RAP RUN FROM 22Z HAS SW WINDS JUST ABOVE THE SURFACE GRADUALLY DIMINISHING THROUGH THE NIGHT. HAVE LLWS DROPPED FROM THE TAFORS AT 05Z THOUGH MAY NEED TO EXTEND IT A BIT FURTHER INTO THE OVERNIGHT IF LOW LEVEL WINDS DO NOT DROP OFF QUITE THAT QUICKLY. PRESSURE GRADIENT WILL INCREASE AGAIN SAT AS ANOTHER LOW DEEPENS AS IT MOVES FROM NW MN ESE TO EASTERN LAKE SUPERIOR DURING THE DAY. SW SURFACE WIND SAT NOT EXPECTED TO BE AS STRONG AS THIS AFTERNOON BUT ARE EXPECTED TO BE GUSTING IN THE MID TO UPPER 20KT RANGE BY MIDDAY. A STRONG COLD FRONT TRAILING SW FROM THE LOW IS PROGGED TO ADVANCE TO ACROSS W CENTRAL LOWER MI...FAR NE IL AND E CENTRAL IA BY 20.00Z AND TO THEN MOVE ACROSS ORD AND MDW DURING THE EARLY EVENING SHIFTING WINDS FROM WSW TO WNW AND GUST 30-35KT AS A STRONG PRESSURE RISE CENTER MOVES SE TOWARD THE LOCAL AREA AS ARCTIC AIR SPILLS FURTHER SOUTHEASTWARD FROM THE UPPER MIDWEST. TRS //ORD AND MDW CONFIDENCE...UPDATED 00Z... * HIGH CONFIDENCE ALL ELEMENTS...EXCEPT MODERATE CONFIDENCE IN WIND SPEED FROM SAT MID-MORNING THROUGH AFTERNOON. TRS //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...MVFR CEILINGS. MONDAY...VFR CEILINGS. TUESDAY...VFR. WEDNESDAY...VFR. THURSDAY...VFR. CHANCE OF SN RESULTING IN MVFR CONDITIONS. TRS && .MARINE... 237 PM CST HIGH PRESSURE REMAINS FROM THE LOWER MISSISSIPPI RIVER VALLEY NORTHEASTWARD ACROSS THE OHIO VALLEY AND MID ATLANTIC THIS AFTERNOON WHILE AND ELONGATED AREA OF LOW PRESSURE IS SPREAD FROM CENTRAL ALBERTA TO LAKE MICHIGAN. A LOW PRESSURE CIRCULATION EMBEDDED WITHIN THE TROUGH IS PUSHING FROM WESTERN WISCONSIN EASTWARD WITH VERY STRONG PRESSURE FALLS OVER LAKE MICHIGAN THANKS TO THE DIFFERENCE IN PRESSURE BETWEEN IT AND THE HIGH TO THE SOUTHEAST. SOUTHWEST GALES CONTINUE ACROSS THE SOUTHERN TWO-THIRDS OR SO OF THE LAKE WITH THE FAR NORTH IN THE TROUGH AXIS RESULTING IN LIGHTER WINDS. THE LOW WILL CROSS THE LAKE THIS EVENING ALLOWING WINDS TO EASE FROM NORTHWEST TO SOUTHEAST THROUGH THE EVENING. NORTH-CENTRAL SECTIONS OF THE LAKE SHOULD SEE WINDS EASE THIS EVENING WITH IT TAKING UNTIL AROUND MIDNIGHT OR SOON AFTER FOR GALES TO DIMINISH SOUTH. WILL LET THE GALE WARNING GO AS-IS FOR NOW BUT IT MAY BE ABLE TO BE CANCELLED EARLY NORTH. FOR THE NEARSHORE WATERS...WILL END THE ILLINOIS SHORES A BIT EARLIER BUT CARRY THE INDIANA SHORELINE UNTIL 09Z AS SCHEDULED BUT IT IS POSSIBLE THIS MAY NEED TO BE SHORTENED. EXPECT THAT A SMALL CRAFT ADVISORY WILL BE NEEDED ONCE GALES DIMINISH. A SECOND LOW WILL DEEPEN ACROSS SASKATCHEWAN TONIGHT AND MOVE TO WESTERN LAKE SUPERIOR BY SATURDAY AFTERNOON. THE LOW WILL THEN FURTHER DEEPEN AS IT CROSSES THE U.P. OF MICHIGAN SATURDAY EVENING AND HEADS TOWARD SOUTHERN QUEBEC BY SUNDAY MORNING. SOUTH TO SOUTHWEST WINDS WILL INTENSIFY SATURDAY WITH LOWER END GALES EXPECTED TO BEGIN DURING THE EARLY AFTERNOON ACROSS THE OPEN WATERS...WITH NEARSHORE AREAS LIKELY HOLDING INTO THE UPPER 20S TO ABOUT 30 KT. WILL PUSH THE START TIME OF THE GALE WATCH FOR THE NEARSHORE WATERS LATER TO 00Z BUT UPGRADE TO A GALE WARNING FOR THE OPEN WATERS FROM 18Z ON WITH THE NORTHERN TWO-THIRDS EXPECTED TO SEE GALES DURING THE AFTERNOON. WINDS WILL TURN WESTERLY THEN NORTHWESTERLY SATURDAY EVENING AS THE LOW AND A COLD FRONT PASS WITH MUCH COLDER AIR ARRIVING. THE COMBINATION OF COLD ADVECTION AND THE DEEPENING LOW PASSING NORTH OF THE LAKE WILL BE VERY FAVORABLE FOR HIGH END GALES ACROSS MUCH OF THE LAKE SATURDAY EVENING AND EARLY SATURDAY NIGHT BEFORE EASING SUNDAY MORNING. IT DOES APPEAR THAT A 3-6 HR PERIOD WILL BE FAVORABLE FOR A FEW STORM FORCE GUSTS TO 50 KT ROUGHLY BETWEEN 03 AND 06 OR 09Z ACROSS CENTRAL PORTIONS OF THE LAKE. WILL HIGHLIGHT THIS IN THE TEXT FOR NOW. WITH THE COLDER AIR...HEAVY FREEZING SPRAY IS ALSO A CONCERN LATE SATURDAY EVENING THROUGH SUNDAY MORNING AS AIR TEMPS FALL INTO THE MID/UPPER TEENS. WILL ISSUE A HEAVY FREEZING SPRAY WATCH FROM 06 TO 18Z SUNDAY. WINDS WILL EASE SUNDAY MORNING AS THE LOW DEPARTS BUT THE STEADY FLOW OF COLDER AIR AND A TIGHT PRESSURE GRADIENT WILL KEEP WINDS ELEVATED THROUGH EARLY NEXT WEEK AND MAY BE MODULATED UP AND DOWN BY PASSING WEAK LOWS. HIGH PRESSURE DOES LOOK TO EVENTUALLY ARRIVE OVER THE LAKE DURING THE MID OR LATE PART OF THE WEEK WHICH WOULD PROVIDE MUCH LIGHTER WINDS. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673- LMZ675-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-LMZ870- LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 3 AM SATURDAY. GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON SATURDAY TO 9 AM SUNDAY. HEAVY FREEZING SPRAY WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366- LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740- LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...MIDNIGHT SUNDAY TO NOON SUNDAY. GALE WATCH...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...6 PM SATURDAY TO 9 AM SUNDAY. GALE WARNING...ILLINOIS NEARSHORE WATERS UNTIL 10 PM FRIDAY. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
509 AM EST THU JAN 17 2013 .SYNOPSIS... LOW PRESSURE WILL QUICKLY TO THE EAST LATE TONIGHT. A STRONG ARCTIC COLD FRONT WILL CROSS THE STATE THURSDAY. HIGH PRESSURE WILL BUILD EAST FRIDAY...WHILE LOW PRESSURE TRACKS SOUTH OF THE GULF OF MAINE. LOW PRESSURE WILL TRACK TOWARDS THE REGION ON SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... MOST OF THE FA IS NOW IN A BREAK BETWEEN SN SHWR ACTION TO OUR E AND NEW SN SHWRS ADVCG EWRD INTO THE REGION FROM QB. IN ADDITION... A SN SQUALL IS CURRENTLY APCHG THE ST LAWRENCE RVR VLY OF ERN QB WITH SEVERAL OBS INDICATING WIND GUSTS TO 40 TO 45 MPH AND NEAR WHITEOUT CONDITIONS OCCURRING WITH THE SQUALL. HRRR GUIDANCE INDICATES THAT SOME PORTION OF THIS LN OF SN SHWRS WILL GET INTO OUR FA THIS MORN...BUT NOT SURE HOW INTENSE THE LN WILL CONTINUE AS IT MOVES TOWARD NB. WE DID GO WITH LIKELY POPS FOR NRN AREAS AND CHC POPS SRN AREAS...HIGHLIGHTING AN HRLY PROGRESSION ACROSS THE REGION FROM 12-16Z. IF WORSE COMES TO WORSE...WE CAN ISSUE A BLOWING SN ADV TO HIGHLIGHT THE PRESENCE OF THIS SN SQUALL AS IT MOVES E THRU SPCLY NRN PTNS OF THE FA WHERE POWDERY SN FELL LAST NGT. BEHIND THE FRONT...TEMPS DROP UP TO 10 TO 15 DEG F WITHIN AN HR...AND THEN CONT TO FALL OFF GRADUALLY THRU THE REMAINDER OF THE AFT WITH BRISK N TO NW WINDS OF 15 TO 25 MPH. THE COMBO OF LOWERING TEMPS AND WINDS HAS WARRANTED A WIND CHILL ADV FOR NW AND FAR NERN ME BEGINNING LATE THIS AFTN AND CONTG THRU THE EVE. WITH WINDS DIMINISHING BLO 5 MPH BY MDNGT OVR NRN PTNS OF THE FA AS A RIDGE OF HI PRESS SETTLES OVR THE REGION...WE BELIEVE THE WIND CHILL ADV FOR THE NW AND FAR NE WILL NO LONGER BE NEEDED AFT MDNGT. E CNTRL AND SPCLY DOWNEAST AREAS WILL BE NEAR THE -20 DEG WIND CHILL CRITERIA LATER TNGT INTO FRI MORN AS WINDS REMAIN A LITTLE STRONGER DUE TO BEING IN THE FAR NRN PTN OF THE GRADIENT ASSOCIATED WITH LOW PRESSURE MOVG NE IN THE OPEN ATLC...SO WE CANNOT RULE OUT THE POSSIBILITY OF ANOTHER WIND CHILL ADV MAY NEED TO BE ISSUED OVR THIS PTN OF THE FA BY THE AFTN FCST UPDATE. LASTLY...WITH MCLR SKIES AND SLACKENING EVE WINDS...ARCTIC INVSN CONDITIONS ARE A GOOD BET FOR OUR NW VLYS LATE TNGT...BRINGING THE COLDEST LOW TEMPS...OF THE SEASON SO FAR...PERHAPS AS LOW 30 BELOW ZERO FOR COLDEST LOCATIONS. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... HIGH PRESSURE DOMINATES FRIDAY WITH BITTERLY COLD TEMPERATURES. HIGHS WILL BE IN THE ZERO TO FIVE BELOW RANGE NORTH OF HOULTON AND SINGLE DIGITS FOR BANGOR AND DOWN EAST. COASTAL LOCATIONS MAY JUST EDGE INTO THE LOW TEENS. WITH WINDS OVER 10 MPH BY MID TO LATE MORNING...EXPECT A STRONG POSSIBILITY OF A WIND CHILL ADVISORY. WIND CHILLS WILL BE -20F TO -30F ALL DAY NORTH OF HOULTON AND NEAR -20F AROUND BANGOR IN THE MORNING. TEMPERATURES WILL FALL QUICKLY FRIDAY EVENING TOWARDS MINUS 10F IN THE CROWN OF MAINE AND TOWARDS ZERO FOR DOWN EAST. HOWEVER...A FAST-MOVING CLIPPER SYSTEM WILL ARRIVE AFTER MIDNIGHT WITH THICKENING CLOUDS. THUS LOWS WILL OCCUR NEAR MIDNIGHT AND TEMPERATURES WILL RISE AFTER WARDS. THIS CLIPPER WILL PRODUCE LIGHT OVERRUNNING SNOW LATE FRIDAY NIGHT THROUGH THE DAY SATURDAY. ANTICIPATE AMOUNTS IN THE ONE TO TWO INCH RANGE IN NORTHERN ZONES...BUT LESS THAN AN INCH DOWN EAST. SOUTHERLY WINDS WILL ALLOW TEMPERATURES TO RISE FROM LATE FRIDAY NIGHT THROUGH THE DAY ON SATURDAY...REACHING THE LOW TO MID 30S ALONG THE COAST AND LOW 20S IN NORTHERN AROOSTOOK COUNTY. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... A LOW PRESSURE SYSTEM WILL INTENSIFY IN THE NORTHERN GREAT LAKES REGION LATE SATURDAY THROUGH SUNDAY MORNING WITH A WARM FRONT EXTENDING EAST INTO NORTHERN MAINE. THE OVERRUNNING SNOW IS EXPECTED TO CONTINUE SATURDAY NIGHT AND INCREASE AFTER MIDNIGHT AS THE LOW MOVES INTO QUEBEC. TEMPERATURES WILL NOT FALL MUCH WITH THE CONTINUING WARM AIR ADVECTION. SOME RAIN MAY MIX WITH THE SNOW IN ZONES 29 AND 30 ALONG THE COAST. THE LATEST NWP GUIDANCE IS SHOWING THE LOW TRACKING FURTHER TO THE NORTH DURING SUNDAY...WITH THE MOST LIKELY TRACK JUST NORTH OF THE SJV. THE RESULT WILL BE AN ADDITIONAL SEVERAL INCHES OF SNOW IN THE CROWN OF MAINE...BUT LITTLE IF ANY ACCUMULATION DOWN EAST. HIGHS ON SUNDAY WILL REACH THE MID TO UPPER 20S NORTH OF HOULTON AND LOW TO MID 30S SOUTH OF HOULTON. THE COLD FRONT FOLLOWING THIS LOW WILL USHER IN ANOTHER ROUND OF BITTERLY COLD TEMPERATURES. TEMPERATURES WILL PLUMMET TO 5 TO 10 BELOW ZERO IN NORTHERN ZONES SUNDAY NIGHT WHILE SINGLE DIGITS ARE EXPECTED FOR BANGOR AND VICINITY. HIGHS WILL STRUGGLE TO REACH ZERO FOR NORTHERN ZONES MONDAY THROUGH THURSDAY. LOWS WILL BE WELL BELOW ZERO. THE BIG QUESTION WILL BE WHETHER WINDS AND CLOUDS ALLOW DECOUPLING OF THE BOUNDARY LAYER AND PRODUCE READINGS AS LOW AS 30 BELOW. THE FIRST CHANCE AT THIS WRITING APPEARS TO BE MONDAY NIGHT. WILL GO FOR MINUS 10 AROUND BANGOR AND LESS THAN MINUS 20 NORTH OF HOULTON ON MONDAY NIGHT. WITH THIS COLD AIR IN PLACE...STORM SYSTEMS ARE EXPECTED TO PASS TO OUR SOUTH FOR MONDAY INTO THURSDAY. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... NEAR TERM: IFR AND MVFR CONDITIONS WILL IMPROVE TO VFR BY THIS AFTN ACROSS DOWNEAST SITES BEHIND AN ARCTIC FRONT AND BY LATE AFTN OVR NRN TAF SITES AFT A PD OF BLOWING AND DRIFTING SNOW BEHIND THE ARCTIC FRONT. BRIEF WHITEOUT CONDITIONS MAY OCCUR AT NRN TAF SITES WITH SN SQL ACTIVITY WITH THE COLD FRONT. ALL SITES WILL THEN REMAIN VFR TNGT. SHORT TERM: VFR FRIDAY INTO FRIDAY EVENING. BECOMING MVFR LATE FRIDAY NIGHT THROUGH SATURDAY NIGHT. FROM HUL NORTHWARD...EXPECT IFR LATER SATURDAY NIGHT THROUGH SUNDAY WHILE TERMINALS SOUTH OF HUL WILL REMAIN MVFR SUNDAY. ALL AREAS WILL BE VFR MONDAY. && .MARINE... NEAR TERM: WILL CONT WITH AN SCA FOR WINDS BEHIND A DEPARTING LOW PRES SYSTEM IN THE MARITIMES AND ALSO BEHIND ARCTIC COLD FRONT XPCTD TO CROSS THE WATERS THIS AFTN. IN ADDITION TO SCA WINDS AND SEAS...COLDER AIR WILL CREATE THE POTENTIAL OF MDT FZG SPY LATE TNGT AFT MDNGT. WW3 WV HTS WERE ABOUT 2 FT TO LOW COMPARED TO OBSVD BUOY WV HTS ERLY THIS MORN...SO WE BLENDED SWAN GFS GUIDANCE AND ADDED ANOTHER FOOT TO IT FOR THIS MORN...THEN BLENDED CLOSER TO WW3 GUIDANCE FOR TNGT. SHORT TERM: AN SCA WILL CONTINUE FRIDAY. THERE MAY BE A BIT OF RESPITE LATE FRIDAY AFTERNOON UNTIL AFTER MIDNIGHT FRIDAY NIGHT BEFORE SCA CONDITIONS RETURN. GALE CONDITIONS ARE POSSIBLE DURING SATURDAY AND AGAIN DURING SUNDAY WITH WIND GUSTS OVER 40 KTS POSSIBLE...ESPECIALLY ON SUNDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WIND CHILL ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT FOR MEZ001>004-010. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR ANZ050>052. && $$ NEAR TERM...VJN SHORT TERM...MCW LONG TERM...MCW AVIATION...VJN MARINE...VJN/MCW
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1122 AM CST THU JAN 17 2013 .AVIATION...18Z TAF ISSUANCE... MVFR CLOUD DECK IN PLACE ACROSS THE NORTHLAND THIS MORNING WILL SLOWLY DISSIPATE THROUGH THE AFTERNOON FROM NORTH TO SOUTH. A FEW LINGERING LIGHT SNOW SHOWERS OR FLURRIES WILL EVENTUALLY COME TO AN END BY MID AFTERNOON. THE NEXT SYSTEM WILL MOVE IN QUICKLY FROM THE SW TONIGHT AND SPREAD LOW-END MVFR/IFR CIGS AND IFR VSBYS IN -SN ACROSS THE REGION. W/NW WINDS TODAY WILL SHIFT TO THE SOUTH TONIGHT...AROUND 5-10 KT. && .PREV DISCUSSION... /ISSUED 1007 AM CST THU JAN 17 2013/ UPDATE... MADE UPDATES TO THE FORECAST THROUGH TONIGHT. THIS WAS TO INCREASE CLOUD COVER TODAY. IT SHOULD TAKE SOME TIME FOR THE CLOUDY SKIES ACROSS THE NORTHLAND TO MOVE EAST AND/OR DISSIPATE...BUT GENERALLY THERE SHOULD BE DECREASING CLOUD COVER THIS AFTERNOON FROM WEST TO EAST. ALSO...THERE WAS NOT A MENTION OF FLURRIES FOR MOST OF THE NORTHLAND...YET THESE LOW CLOUDS ARE PRODUCING FLURRIES HERE AND THERE. THEREFORE...ADDED FLURRIES FOR MOST OF THE NORTHLAND THROUGH THE FIRST HALF OF THE AFTERNOON. CANCELLED THE WIND CHILL ADVISORY FOR NORTHERN ST. LOUIS COUNTY...KOOCHICHING COUNTY...AND THE SOUTHERN PART OF THE NORTH SHORE SINCE THE WIND CHILL VALUES HAVE IMPROVED WITH THE INCREASING TEMPERATURES. ALSO MADE CHANGES TO THE FORECAST FOR TONIGHT TO BETTER TIME THE LIKELY SNOW THAT WILL MOVE INTO THE FA WITH THE WARM AIR ADVECTION ALOFT. PREV DISCUSSION... /ISSUED 554 AM CST THU JAN 17 2013/ AVIATION...12Z TAFS CEILINGS FROM 3500-5000FEET COVERED MUCH OF THE NORTHLAND THIS MORNING...WITH MVFR CEILINGS AND LIGHT SNOW MOVING TOWARD KBRD. THESE LOWER CEILINGS ARE FORECAST BY THE RAP TO AFFECT KHIB/KDLH/KHYR LATER TODAY...AND WE PUT THEM IN THE LATEST TAF. CLOUDS WILL DIMINISH LATER THIS AFTERNOON/EARLY EVENING...BEFORE INCREASING AGAIN OVERNIGHT IN AN AREA OF WAA. SOME LIGHT SNOW MAY ALSO DEVELOP LATE TONIGHT. PREV DISCUSSION... /ISSUED 410 AM CST THU JAN 17 2013/ SHORT TERM...TODAY THROUGH FRIDAY. AT 4 AM...CLOUDS WERE ON THE INCREASE ACROSS THE CWA. THE RESULT WAS A BIT OF IMPROVEMENT IN TEMPS AND WIND CHILL READINGS. HAVE REMOVED ITASCA COUNTY...AND THE DULUTH AND SUPERIOR AREAS FROM THE WIND CHILL ADVISORY...AS WIND CHILL READINGS HAD IMPROVED A BIT. WILL LIKELY BE ABLE TO REMOVE OTHER COUNTIES AS THE MORNING WEARS ON DUE TO THE INCREASING CLOUDS. THE MAIN FOCUS FOR TODAY WILL BE THE WIND CHILL READINGS THIS MORNING...ALONG WITH CLOUD TRENDS. THERE WILL LIKELY BE SOME DECREASE IN CLOUDS ACROSS THE CWA TODAY. THE NAM ACTUALLY PICKS UP ON THE BAND OF CLOUDS MOVING INTO NORTHERN MN...AND IT CARRIES THAT SHORTWAVE TO THE EAST AS THE DAY WEARS ON. HIGH TEMPS WILL LIKELY REMAIN A BIT BELOW ZERO IN THE FAR NORTH TODAY...BUT WILL APPROACH 10 ABOVE IN THE SOUTH. THE MAIN FOCUS FOR TONIGHT AND FRIDAY IS THE DEVELOPING LOW PRESSURE SYSTEM THAT IS EXPECTED TO SLIDE INTO THE LAKE SUPERIOR REGION THROUGH THE END OF THE WEEK. HAVE INCREASED POPS CONSIDERABLY LATER TONIGHT AND INTO FRIDAY. COULD SEE SOME 2 TO 4 INCH AMOUNTS IN THE NORTH...AND POSSIBLY EVEN 3 TO 5 ACROSS THE ARROWHEAD. WILL ALSO NEED TO WATCH THE NORTH SHORE FOR THE POSSIBILITY OF LOCALIZED HIGHER AMOUNTS DUE TO LAKE ENHANCEMENT. MAY NEED TO ISSUE ADVISORIES FOR PORTIONS OF THE NORTHLAND IN LATER FORECAST PACKAGES. TEMPERATURES WILL WARM CONSIDERABLY ON FRIDAY...ESPECIALLY ACROSS THE SOUTH...AS THE SOUTHERN HALF OF THE CWA SHOULD BE IN THE WARM SECTOR DURING THE DAY. LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY. MUCH COLDER TEMPERATURES WILL BE MOVING INTO THE NORTHLAND IN THE EXTENDED PERIOD. A COUPLE SHORTWAVES WILL AFFECT THE NORTHLAND FRIDAY NIGHT INTO SATURDAY...WITH THE STRONGER WAVE/LOW OCCURRING SATURDAY. LIGHT SNOW WILL OCCUR FRIDAY NIGHT...MAINLY NORTH WITH OVERNIGHT ACCUMULATIONS MAINLY RANGING FROM A DUSTING TO PERHAPS AN INCH. THE STRONGER WAVE ON SATURDAY WILL BE ACCOMPANIED BY A DEEPENING LOW AND AS THEY PASS...MUCH COLDER AIR WILL POUR INTO THE REGION. SOME ADDITIONAL SNOWFALL WILL OCCUR SATURDAY...AGAIN MAINLY NORTH AND AMOUNTS WILL BE SOMEWHAT LIMITED FOR MOST AREAS. A FEW INCHES WILL BE POSSIBLE OVER THE ARROWHEAD. WE INCREASED TEMPS FRIDAY NIGHT INTO SATURDAY...BEFORE THE COLD AIR MOVES IN. TEMPERATURES WILL START TO FALL LATER SATURDAY...ESPECIALLY OVER OUR MINNESOTA ZONES. STRONG WEST-NORTHWEST WINDS WILL DEVELOP SATURDAY INTO SATURDAY NIGHT...AND WE INCREASED THEM QUITE A BIT. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED SATURDAY NIGHT OVER OUR MINNESOTA ZONES...AND EXTREME NORTHWEST WISCONSIN ZONES. OUTSIDE OF AN EXTENDED PERIOD OF LAKE EFFECT OF SNOW ALONG PORTIONS OF THE SOUTH SHORE...THE MAIN FOCUS SATURDAY NIGHT INTO WEDNESDAY WILL BE THE COLD. LOW WILL DROP INTO THE TEENS BELOW ZERO SATURDAY NIGHT OVER OUR NORTHERN ZONES...AND SINGLE DIGITS BELOW OVER NORTHWEST WISCONSIN. WE HAVE TEENS TO AROUND 25 BELOW ZERO SUNDAY NIGHT AND MONDAY NIGHT AND TEENS BELOW TUESDAY NIGHT. HIGHS SUNDAY WILL REMAIN AT OR BELOW ZERO OVER MOST OF NORTHEAST MINNESOTA...AND ZERO TO 5 ABOVE IN NORTHWEST WISCONSIN...AND BE A FEW DEGREES COLDER ON MONDAY. A FAVORABLE PERIOD OF LES WILL OCCUR SATURDAY NIGHT INTO SUNDAY NIGHT...ALTHOUGH 850MB TEMPERATURES WILL BE VERY COLD BY SUNDAY NIGHT WHICH MAY LIMIT SNOW ACCUMULATIONS. SOME SIGNIFICANT SNOW ACCUMULATIONS WILL BE POSSIBLE IN THE SNOWBELT SATURDAY NIGHT INTO SUNDAY. && .POINT TEMPS/POPS... DLH 6 -3 26 20 / 10 60 70 30 INL 0 -13 17 7 / 10 60 70 50 BRD 9 1 32 19 / 20 60 20 10 HYR 8 -2 34 17 / 30 60 60 20 ASX 9 -1 29 18 / 10 30 70 30 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ012-021. WI...NONE. LS...NONE. && $$ AVIATION...TENTINGER
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1007 AM CST THU JAN 17 2013 .UPDATE... MADE UPDATES TO THE FORECAST THROUGH TONIGHT. THIS WAS TO INCREASE CLOUD COVER TODAY. IT SHOULD TAKE SOME TIME FOR THE CLOUDY SKIES ACROSS THE NORTHLAND TO MOVE EAST AND/OR DISSIPATE...BUT GENERALLY THERE SHOULD BE DECREASING CLOUD COVER THIS AFTERNOON FROM WEST TO EAST. ALSO...THERE WAS NOT A MENTION OF FLURRIES FOR MOST OF THE NORTHLAND...YET THESE LOW CLOUDS ARE PRODUCING FLURRIES HERE AND THERE. THEREFORE...ADDED FLURRIES FOR MOST OF THE NORTHLAND THROUGH THE FIRST HALF OF THE AFTERNOON. CANCELLED THE WIND CHILL ADVISORY FOR NORTHERN ST. LOUIS COUNTY...KOOCHICHING COUNTY...NAD THE SOUTHERN PART OF THE NORTH SHORE SINCE THE WIND CHILL VALUES HAVE IMPROVED WITH THE INCREASING TEMPERATURES. ALSO MADE CHANGES TO THE FORECAST FOR TONIGHT TO BETTER TIME THE LIKELY SNOW THAT WILL MOVE INTO THE FA WITH THE WARM AIR ADVECTION ALOFT. && .PREV DISCUSSION... /ISSUED 554 AM CST THU JAN 17 2013/ AVIATION...12Z TAFS CEILINGS FROM 3500-5000FEET COVERED MUCH OF THE NORTHLAND THIS MORNING...WITH MVFR CEILINGS AND LIGHT SNOW MOVING TOWARD KBRD. THESE LOWER CEILINGS ARE FORECAST BY THE RAP TO AFFECT KHIB/KDLH/KHYR LATER TODAY...AND WE PUT THEM IN THE LATEST TAF. CLOUDS WILL DIMINISH LATER THIS AFTERNOON/EARLY EVENING...BEFORE INCREASING AGAIN OVERNIGHT IN AN AREA OF WAA. SOME LIGHT SNOW MAY ALSO DEVELOP LATE TONIGHT. PREV DISCUSSION... /ISSUED 410 AM CST THU JAN 17 2013/ SHORT TERM...TODAY THROUGH FRIDAY. AT 4 AM...CLOUDS WERE ON THE INCREASE ACROSS THE CWA. THE RESULT WAS A BIT OF IMPROVEMENT IN TEMPS AND WIND CHILL READINGS. HAVE REMOVED ITASCA COUNTY...AND THE DULUTH AND SUPERIOR AREAS FROM THE WIND CHILL ADVISORY...AS WIND CHILL READINGS HAD IMPROVED A BIT. WILL LIKELY BE ABLE TO REMOVE OTHER COUNTIES AS THE MORNING WEARS ON DUE TO THE INCREASING CLOUDS. THE MAIN FOCUS FOR TODAY WILL BE THE WIND CHILL READINGS THIS MORNING...ALONG WITH CLOUD TRENDS. THERE WILL LIKELY BE SOME DECREASE IN CLOUDS ACROSS THE CWA TODAY. THE NAM ACTUALLY PICKS UP ON THE BAND OF CLOUDS MOVING INTO NORTHERN MN...AND IT CARRIES THAT SHORTWAVE TO THE EAST AS THE DAY WEARS ON. HIGH TEMPS WILL LIKELY REMAIN A BIT BELOW ZERO IN THE FAR NORTH TODAY...BUT WILL APPROACH 10 ABOVE IN THE SOUTH. THE MAIN FOCUS FOR TONIGHT AND FRIDAY IS THE DEVELOPING LOW PRESSURE SYSTEM THAT IS EXPECTED TO SLIDE INTO THE LAKE SUPERIOR REGION THROUGH THE END OF THE WEEK. HAVE INCREASED POPS CONSIDERABLY LATER TONIGHT AND INTO FRIDAY. COULD SEE SOME 2 TO 4 INCH AMOUNTS IN THE NORTH...AND POSSIBLY EVEN 3 TO 5 ACROSS THE ARROWHEAD. WILL ALSO NEED TO WATCH THE NORTH SHORE FOR THE POSSIBILITY OF LOCALIZED HIGHER AMOUNTS DUE TO LAKE ENHANCEMENT. MAY NEED TO ISSUE ADVISORIES FOR PORTIONS OF THE NORTHLAND IN LATER FORECAST PACKAGES. TEMPERATURES WILL WARM CONSIDERABLY ON FRIDAY...ESPECIALLY ACROSS THE SOUTH...AS THE SOUTHERN HALF OF THE CWA SHOULD BE IN THE WARM SECTOR DURING THE DAY. LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY. MUCH COLDER TEMPERATURES WILL BE MOVING INTO THE NORTHLAND IN THE EXTENDED PERIOD. A COUPLE SHORTWAVES WILL AFFECT THE NORTHLAND FRIDAY NIGHT INTO SATURDAY...WITH THE STRONGER WAVE/LOW OCCURRING SATURDAY. LIGHT SNOW WILL OCCUR FRIDAY NIGHT...MAINLY NORTH WITH OVERNIGHT ACCUMULATIONS MAINLY RANGING FROM A DUSTING TO PERHAPS AN INCH. THE STRONGER WAVE ON SATURDAY WILL BE ACCOMPANIED BY A DEEPENING LOW AND AS THEY PASS...MUCH COLDER AIR WILL POUR INTO THE REGION. SOME ADDITIONAL SNOWFALL WILL OCCUR SATURDAY...AGAIN MAINLY NORTH AND AMOUNTS WILL BE SOMEWHAT LIMITED FOR MOST AREAS. A FEW INCHES WILL BE POSSIBLE OVER THE ARROWHEAD. WE INCREASED TEMPS FRIDAY NIGHT INTO SATURDAY...BEFORE THE COLD AIR MOVES IN. TEMPERATURES WILL START TO FALL LATER SATURDAY...ESPECIALLY OVER OUR MINNESOTA ZONES. STRONG WEST-NORTHWEST WINDS WILL DEVELOP SATURDAY INTO SATURDAY NIGHT...AND WE INCREASED THEM QUITE A BIT. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED SATURDAY NIGHT OVER OUR MINNESOTA ZONES...AND EXTREME NORTHWEST WISCONSIN ZONES. OUTSIDE OF AN EXTENDED PERIOD OF LAKE EFFECT OF SNOW ALONG PORTIONS OF THE SOUTH SHORE...THE MAIN FOCUS SATURDAY NIGHT INTO WEDNESDAY WILL BE THE COLD. LOW WILL DROP INTO THE TEENS BELOW ZERO SATURDAY NIGHT OVER OUR NORTHERN ZONES...AND SINGLE DIGITS BELOW OVER NORTHWEST WISCONSIN. WE HAVE TEENS TO AROUND 25 BELOW ZERO SUNDAY NIGHT AND MONDAY NIGHT AND TEENS BELOW TUESDAY NIGHT. HIGHS SUNDAY WILL REMAIN AT OR BELOW ZERO OVER MOST OF NORTHEAST MINNESOTA...AND ZERO TO 5 ABOVE IN NORTHWEST WISCONSIN...AND BE A FEW DEGREES COLDER ON MONDAY. A FAVORABLE PERIOD OF LES WILL OCCUR SATURDAY NIGHT INTO SUNDAY NIGHT...ALTHOUGH 850MB TEMPERATURES WILL BE VERY COLD BY SUNDAY NIGHT WHICH MAY LIMIT SNOW ACCUMULATIONS. SOME SIGNIFICANT SNOW ACCUMULATIONS WILL BE POSSIBLE IN THE SNOWBELT SATURDAY NIGHT INTO SUNDAY. && .POINT TEMPS/POPS... DLH 6 -3 26 20 / 10 60 70 30 INL 0 -13 17 7 / 10 60 70 50 BRD 9 1 32 19 / 10 60 20 10 HYR 8 -2 34 17 / 10 60 60 20 ASX 9 -1 29 18 / 10 30 70 30 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ012-021. WI...NONE. LS...NONE. && $$ SHORT TERM...GROCHOCINSKI LONG TERM....TENTINGER
AREA FORECAST DISCUSSION
NWS DULUTH MN
554 AM CST THU JAN 17 2013 .AVIATION...12Z TAFS CEILINGS FROM 3500-5000FEET COVERED MUCH OF THE NORTHLAND THIS MORNING...WITH MVFR CEILINGS AND LIGHT SNOW MOVING TOWARD KBRD. THESE LOWER CEILINGS ARE FORECAST BY THE RAP TO AFFECT KHIB/KDLH/KHYR LATER TODAY...AND WE PUT THEM IN THE LATEST TAF. CLOUDS WILL DIMINISH LATER THIS AFTERNOON/EARLY EVENING...BEFORE INCREASING AGAIN OVERNIGHT IN AN AREA OF WAA. SOME LIGHT SNOW MAY ALSO DEVELOP LATE TONIGHT. && .PREV DISCUSSION... /ISSUED 410 AM CST THU JAN 17 2013/ SHORT TERM...TODAY THROUGH FRIDAY. AT 4 AM...CLOUDS WERE ON THE INCREASE ACROSS THE CWA. THE RESULT WAS A BIT OF IMPROVEMENT IN TEMPS AND WIND CHILL READINGS. HAVE REMOVED ITASCA COUNTY...AND THE DULUTH AND SUPERIOR AREAS FROM THE WIND CHILL ADVISORY...AS WIND CHILL READINGS HAD IMPROVED A BIT. WILL LIKELY BE ABLE TO REMOVE OTHER COUNTIES AS THE MORNING WEARS ON DUE TO THE INCREASING CLOUDS. THE MAIN FOCUS FOR TODAY WILL BE THE WIND CHILL READINGS THIS MORNING...ALONG WITH CLOUD TRENDS. THERE WILL LIKELY BE SOME DECREASE IN CLOUDS ACROSS THE CWA TODAY. THE NAM ACTUALLY PICKS UP ON THE BAND OF CLOUDS MOVING INTO NORTHERN MN...AND IT CARRIES THAT SHORTWAVE TO THE EAST AS THE DAY WEARS ON. HIGH TEMPS WILL LIKELY REMAIN A BIT BELOW ZERO IN THE FAR NORTH TODAY...BUT WILL APPROACH 10 ABOVE IN THE SOUTH. THE MAIN FOCUS FOR TONIGHT AND FRIDAY IS THE DEVELOPING LOW PRESSURE SYSTEM THAT IS EXPECTED TO SLIDE INTO THE LAKE SUPERIOR REGION THROUGH THE END OF THE WEEK. HAVE INCREASED POPS CONSIDERABLY LATER TONIGHT AND INTO FRIDAY. COULD SEE SOME 2 TO 4 INCH AMOUNTS IN THE NORTH...AND POSSIBLY EVEN 3 TO 5 ACROSS THE ARROWHEAD. WILL ALSO NEED TO WATCH THE NORTH SHORE FOR THE POSSIBILITY OF LOCALIZED HIGHER AMOUNTS DUE TO LAKE ENHANCEMENT. MAY NEED TO ISSUE ADVISORIES FOR PORTIONS OF THE NORTHLAND IN LATER FORECAST PACKAGES. TEMPERATURES WILL WARM CONSIDERABLY ON FRIDAY...ESPECIALLY ACROSS THE SOUTH...AS THE SOUTHERN HALF OF THE CWA SHOULD BE IN THE WARM SECTOR DURING THE DAY. LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY. MUCH COLDER TEMPERATURES WILL BE MOVING INTO THE NORTHLAND IN THE EXTENDED PERIOD. A COUPLE SHORTWAVES WILL AFFECT THE NORTHLAND FRIDAY NIGHT INTO SATURDAY...WITH THE STRONGER WAVE/LOW OCCURRING SATURDAY. LIGHT SNOW WILL OCCUR FRIDAY NIGHT...MAINLY NORTH WITH OVERNIGHT ACCUMULATIONS MAINLY RANGING FROM A DUSTING TO PERHAPS AN INCH. THE STRONGER WAVE ON SATURDAY WILL BE ACCOMPANIED BY A DEEPENING LOW AND AS THEY PASS...MUCH COLDER AIR WILL POUR INTO THE REGION. SOME ADDITIONAL SNOWFALL WILL OCCUR SATURDAY...AGAIN MAINLY NORTH AND AMOUNTS WILL BE SOMEWHAT LIMITED FOR MOST AREAS. A FEW INCHES WILL BE POSSIBLE OVER THE ARROWHEAD. WE INCREASED TEMPS FRIDAY NIGHT INTO SATURDAY...BEFORE THE COLD AIR MOVES IN. TEMPERATURES WILL START TO FALL LATER SATURDAY...ESPECIALLY OVER OUR MINNESOTA ZONES. STRONG WEST-NORTHWEST WINDS WILL DEVELOP SATURDAY INTO SATURDAY NIGHT...AND WE INCREASED THEM QUITE A BIT. A WIND CHILL ADVISORY WILL LIKELY BE NEEDED SATURDAY NIGHT OVER OUR MINNESOTA ZONES...AND EXTREME NORTHWEST WISCONSIN ZONES. OUTSIDE OF AN EXTENDED PERIOD OF LAKE EFFECT OF SNOW ALONG PORTIONS OF THE SOUTH SHORE...THE MAIN FOCUS SATURDAY NIGHT INTO WEDNESDAY WILL BE THE COLD. LOW WILL DROP INTO THE TEENS BELOW ZERO SATURDAY NIGHT OVER OUR NORTHERN ZONES...AND SINGLE DIGITS BELOW OVER NORTHWEST WISCONSIN. WE HAVE TEENS TO AROUND 25 BELOW ZERO SUNDAY NIGHT AND MONDAY NIGHT AND TEENS BELOW TUESDAY NIGHT. HIGHS SUNDAY WILL REMAIN AT OR BELOW ZERO OVER MOST OF NORTHEAST MINNESOTA...AND ZERO TO 5 ABOVE IN NORTHWEST WISCONSIN...AND BE A FEW DEGREES COLDER ON MONDAY. A FAVORABLE PERIOD OF LES WILL OCCUR SATURDAY NIGHT INTO SUNDAY NIGHT...ALTHOUGH 850MB TEMPERATURES WILL BE VERY COLD BY SUNDAY NIGHT WHICH MAY LIMIT SNOW ACCUMULATIONS. SOME SIGNIFICANT SNOW ACCUMULATIONS WILL BE POSSIBLE IN THE SNOWBELT SATURDAY NIGHT INTO SUNDAY. && .POINT TEMPS/POPS... DLH 4 -1 26 20 / 10 60 70 30 INL -4 -14 17 7 / 10 60 70 50 BRD 9 1 32 19 / 10 60 20 10 HYR 7 -3 34 17 / 10 60 60 20 ASX 6 -1 29 18 / 20 60 70 30 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ010>012-019>021. WI...NONE. LS...NONE. && $$ SHORT TERM...DAP LONG TERM....MELDE AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
424 AM CST THU JAN 17 2013 .DISCUSSION... OVERVIEW...PATTERN STILL FAVORING A SERIES OF ALBERTA CLIPPERS THROUGH THE EXTENDED. THE FIRST ARRIVES TONIGHT QUICK ON THE HEELS OF A PASSING SURFACE HIGH. THIS WILL BRING LIGHT SNOW TO NORTHERN MN THROUGH SATURDAY. WHILE LIGHT SNOW IS ALSO POSSIBLE IN CENTRAL MN AND PORTIONS OF WESTERN WI...THE MAIN IMPACTS WILL BE THE DRAMATIC ARCTIC FRONT ASSOCIATED WITH THIS SYSTEM. WINDS AND FRIGID TEMPERATURES ARE STILL EXPECTED SATURDAY NIGHT THROUGH SUNDAY. THE WIND WILL DIMINISH MONDAY...BUT THIS WILL BE ARE COLDEST DAY OF THE SEASON SO FAR. MANY LOCATIONS WILL NOT CLIMB ABOVE ZERO MONDAY. THE PATTERN LOOKS TO BECOME SLIGHTLY MORE ACTIVE IN TERMS OF PRECIPITATION FOR THE LAST WEEK IN JANUARY. STRATUS DECK IS SLOWLY ENGULFING SOUTHERN MN AND WESTERN WI THIS MORNING. WITH NORTHWEST FLOW AND WEAK COLD AIR ADVECTION TODAY TO GO ALONG WITH WHAT COULD AMOUNT TO A MOSTLY CLOUDY DAY...HARD TO EXPECT MUCH WARMING THIS AFTERNOON. LOWERED TEMPS SLIGHTLY AND ARE MAINLY ONLY RISING TEMPS 4-7 DEGREES FROM WHERE WE CURRENTLY SIT THIS MORNING. AN ALBERTA CLIPPER COMES IN FAST TONIGHT...BUT THE WAVE IS WEAK INITIALLY AND DOESN`T REALLY STRENGTHEN UNTIL SATURDAY MORNING WHEN A VIGOROUS SHORT WAVE COMES CRUISING DOWN FROM ALASKA. AT THAT POINT...THE SURFACE CYCLONE DEEPENS 5-10 MB IN ROUGHLY 12 HOURS. THE CLIPPER SEEMS TO BE DIABATICALLY INTERACTING WITH LAKE SUPERIOR...WHICH MAY BE CONTRIBUTING TO THE DEEPENING. STILL HAVE LIGHT SNOW FORECASTED ACROSS CENTRAL MN IN NORTHERN PORTIONS OF THE MPX FORECAST AREA. WE INITIALLY GAVE MOISTURE OVER A LARGE DEPTH OF THE ATMOSPHERE THIS MORNING ACROSS WESTERN/CENTRAL MN...BUT WE LOSE THE RH AT SOME POINT THIS AFTERNOON. SO...LIKE WEDNESDAY MORNING...FREEZING DRIZZLE CAN NOT BE COMPLETELY RULED OUT WHERE SNOW IS FORECASTED LATE THIS EVENING. WE EVENTUALLY FEEL THE COLUMN WILL BE SATURATED ABOVE -10 C...SO LIGHT SNOW SHOULD BE THE DOMINATE P-TYPE BY SUNRISE FRIDAY MORNING. WE INCREASED MAX TEMPS ON FRIDAY GIVEN WHAT WE MANAGED YESTERDAY AND WHAT IS EXPECTED WITH THE WARM FRONT. WE SHOULD SEE PLENTY OF LOWER 40S IN SOUTHERN MN. THE LONE QUESTION WOULD BE IF THE SYSTEM SLOWS DOWN BY 3-6 HOURS AND THE SURFACE WINDS REMAIN SOUTHEAST LONGER ON FRIDAY. IT WOULD CERTAINLY STILL BE WELL ABOVE NORMAL IF THE SLOWER SOLUTION WOULD HAPPEN...BUT HAD ENOUGH CONFIDENCE TO BLEND IN SOME ECMWF AND BIAS CORRECTED ECMWF TO THE PREVIOUS FORECAST TO GIVE US A BOOST IN TEMPS. THE SOUTHERLY FLOW IS STRONG AND MIXING SHOULD BE GOOD FOR MID JANUARY. ANY SNOW ASSOCIATED WITH THIS FIRST CLIPPER SYSTEM /THURSDAY NIGHT AND FRIDAY/ SHOULD BE VERY MINOR AND THE MAIN IMPACTS WILL COME FROM THE ASSOCIATED STRONG ARCTIC FRONT. THE COMBINATION OF THE DEEPENING CLIPPER AND BUILDING HIGH IN THE DAKOTAS ESTABLISH A VERY NICE PACKING OF ISOBARS AND THE 17.00Z GFS/ECMWF/NAM ALL SHOW 40-50 KTS OUT OF THE NORTHWEST BEHIND THE ARCTIC BOUNDARY. WE INCREASED TEMPERATURES SATURDAY GIVEN THE TIMING OF THIS BOUNDARY...WHICH SHOULD LEAVE ROOM FOR A MILD JANUARY MORNING AND EVEN EARLY AFTERNOON ACROSS THE FORECAST AREA. HOWEVER...THE FRONT COMES IN VERY FAST AND WESTERN MN WILL ALREADY SEE DRAMATICALLY FALLING TEMPS AND STRONG WINDS BY SATURDAY EVENING. WE WILL LIKELY NEED A WIND SHILL ADVISORY AS EARLY AS 00Z SUNDAY WITH THIS SURGE. A REINFORCING SHOT OF COLDER AIR ARRIVES SUNDAY...ALTHOUGH THE MOST DRAMATIC CHANGES IN TEMPERATURE WILL STILL OCCUR SATURDAY/SATURDAY NIGHT. WINDS CHILLS WILL BE IN THE -25 TO -40 RANGE LATE THIS WEEKEND AND ON MONDAY...AND MONDAY WILL STRUGGLE TO REACH ZERO IN EASTERN MN AND WI. WESTERN PORTIONS OF THE FORECAST AREA HAVE ALMOST NO CHANCE OF REACHING ZERO ON MONDAY. THE EXTENDED FORECAST STILL POINTS TO A BREAKDOWN OF THE STRONG RIDGING ALONG THE WEST COAST AND A RELAXATION OF THE DEEP TROUGHING OVER THE EASTERN CONUS. THE PREVIOUS ECMWF ENSEMBLE MEAN AND GEFS MEAN SHOW GOOD CORRELATION THROUGH NEXT WEEK WITH THE INCOMING SYSTEM IN THE PACIFIC NORTHWEST NEXT WEDNESDAY. LAST NIGHTS OPERATIONAL RUNS ARE COMING AROUND AS WELL. CHANCES FOR MORE WIDESPREAD PRECIPITATION WILL INCREASE AS THE WEST COAST WAVE MOVES THROUGH THE NORTHERN ROCKIES AND ONTO THE NORTEHRN PLAINS BY MIDWEEK BUT ONLY MODEST QPF AMOUNTS ARE FORECAST. THIS IS STILL A BREAK FROM WHAT WE`VE SEEN AROUND HERE SINCE THE HOLIDAYS. AT THIS POINT THE SYSTEM LATE NEXT WEEK REMAINS WARM ENOUGH TO CONSIDER A RAIN/SNOW MIX...BUT STILL WAY TOO FAR OUT THERE TO GET SERIOUS ABOUT P-TYPE. && .AVIATION.../06Z TAF ISSUANCE/ MAIN FORECAST CONCERN THIS TAF PERIOD IS THE POTENTIAL FOR MVFR CIGS TO MOVE INTO THE AREA FROM THE NORTHWEST OVERNIGHT AND THURSDAY MORNING. 11-3.9 MICRON SATELLITE IMAGERY SHOWS A BLOB OF LLVL MOISTURE OVER NORTH DAKOTA ALONG THE WESTERN PERIPHERY OF THE SURFACE RIDGE. BOTH THE HRRR /CLOUDBASE/ AND RAP /925-850MB MOISTURE/ PROGS SHOW THIS AREA OF MOISTURE BETWEEN 2000 AND 4000 FT ADVECTING INTO THE MN BETWEEN 08Z AND 12Z...AND WI ON THURSDAY MORNING. WILL RETAIN A SCT-BKN MVFR LEVEL DECK IN THE TAF ACCORDINGLY. THE 925MB LAYER IS PROGGED TO DRY OUT THURSDAY AFTERNOON /MN/ AND EARLY EVE /WI/...BUT QUICKLY BE REPLACED BY A WEST TO EAST SURGE OF 850-700MB MOISTURE BETWEEN 03Z AND 12Z FRIDAY. WILL INTRODUCE SNOW INTO KAXN AROUND 03Z FRIDAY...BUT ONSET FOR THE REMAINDER OF THE SITES WILL MOST LIKELY BE BEYOND THIS TAF PERIOD. NORTHWEST WINDS AT 5 TO 10 KTS WILL PREVAIL THROUGH THE PERIOD. KMSP...SCT MVFR LEVEL CLOUDS /2000 FT/ WILL BE POSSIBLE AFTER 12Z THURSDAY...ALONG WITH A BKN VFR DECK /3500 FT/. THE 2KFT DECK COULD BRIEFLY GO BROKEN ON THURSDAY MORNING...BUT CONFIDENCE IS NOT HIGH ON THAT. CLEARING ENSUES IN THE AFTERNOON...WITH ANOTHER ROUND OF CLOUDS /LOW-END VFR CIGS/ ARRIVING AFTER 06Z FRIDAY. /OUTLOOK FOR KMSP/ FRI...VFR. CHC OF -SN AND MVFR VIS/CIG IN MORNING. WIND SW 5-15 KTS. SAT...MVFR CIGS LIKELY. AFTERNOON -SN POSSIBLE. W WIND 5 KTS BECOMING NW 15-20 KTS WITH GUSTS TO 30 KTS. SUN...CHANCE OF -SN WITH MVFR OR LOWER CIG/VIS. WINDS W 5-10 KTS BECOMING NW 15-20 KTS LATE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ CLF/LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1050 PM CST WED JAN 16 2013 .UPDATE...FOR 06Z AVIATION DISCUSSION BELOW && .DISCUSSION.../ISSUED 358 PM CST WED JAN 16 2013/ TONIGHT AND THURSDAY...LOW PRES TRIPLE POINT CENTER TRAVERSING ESE THRU WRN WI WITH THE CDFNT SNAKING EWD THRU KMSP TWD KABR...AND THIS CDFNT WILL CONTINUE TO PRES SE THRU THE REST OF THE EVE. BATCH OF -SN THAT PUSHED THROUGH MAINLY WRN AND SRN PORTIONS OF THE TWIN CITIES REGION HAS SHIFTED OFF TO THE SE SO AM NOT EXPECTING MUCH MORE OF ANY ACCUMULATING OR VISIBILITY-HAMPERING SNOWFALL. THE SNOW WILL COME TO AN END OVER THE MPX CWFA BY LATE EVENING THEN COLDER HIGH PRES WILL SLIDE SE LATE TNGT THRU TMRW. SKIES WILL PARTIALLY CLEAR OUT...BUT THE MAIN IMPACT WILL BE STRONGER CAA. AFTER HIGHS THAT RANGED THRU THE 30S THIS AFTN...THE POST-FRONTAL CAA WILL FORCE LOWS THAT WILL SPAN FROM 10 DEGREES ABOVE ZERO TO 10 DEGREES BELOW ZERO TONIGHT. THIS WILL THEN BE FOLLOWED BY HIGHS FROM AROUND 10 TO THE LOWER 20S FOR THU. THURSDAY NIGHT THROUGH SATURDAY...THE AREA OF HIGH PRES WILL ONLY BE SHORT-LIVED AS IT SHIFTS OFF TO THE SE THU NIGHT INTO FRI WHILE A WMFNT NUDGES IN FROM THE W. THIS WILL RESULT IN NOT ONLY A WARMING TREND FRI INTO FRI NIGHT BUT ALSO THE POTENTIAL FOR SOME SNOW SHOWERS OR LIGHT SNOW FOR MAINLY NRN AND ERN PORTIONS OF THE MPX CWFA THU NIGHT THRU SAT AS THE FNT WILL SLOWLY LIFT OUT AND GIVE WAY TO SEVERAL UPPER LEVEL DISTURBANCES PLUS A TRAILING CDFNT FOR SAT. POPS ARE NO HIGHER THAN CHC RANGE AND ACCUMULATIONS...IF ANY...WILL BE MINOR. AS FOR TEMPS...THE SIGNIFICANT WARM-UP FOR FRI WILL BRING HIGHS AROUND 40 NEAR THE IA BORDER WITH 30S ELSEWHERE THROUGHOUT THE CWFA. HOWEVER...THE MAIN CDFNT WHICH WILL BE THE FOCUS FOR A SIGNIFICANT ARCTIC CHILL WILL PUSH THROUGH LATE SAT SO ALTHOUGH HIGHS WILL DROP OFF ONLY TO THE LOW 20S TO LOW 30S... CAA WILL ABSOLUTELY COMMENCE BY LATE DAY SAT. WINDS WILL ALSO BE ON THE INCRS DURG THE DAY SAT WITH A TIGHT POST-FRONTAL PRES GRADIENT AND STRONG JETTING. WIND CHILL VALUES BY LATE DAY SATURDAY WILL BE IN THE SINGLE DIGITS IN FAR SRN AND ERN PORTIONS... WHILE NRN AND WRN PORTIONS WILL DROP TO AS LOW AS 20 DEGREES BELOW ZERO. SATURDAY NIGHT THROUGH TUESDAY...THE ARCTIC BLAST WILL COMMENCE OVER THE REGION STARTING SAT NIGHT AS A 1040-1050MB HIGH PRES CENTER FROM NRN CANADA WILL DROP INTO THE NORTH-CENTRAL CONUS. IT WILL SETTLE OVER THE AREA MON INTO MON NIGHT...MAKING THESE TWO PERIODS THE COLDEST THIS REGION HAS SEEN IN SOME TIME. BREEZY CONDITIONS WILL ALSO STILL BE PRESENT WITH THE COLD AIR...SO COMBINING HIGHS RANGING FROM ZERO TO 10 BELOW ZERO ON MON FOLLOWED BY LOWS MON NIGHT BETWEEN 10 AND 20 BELOW ZERO WILL MAKE FOR WIND CHILL VALUES BETWEEN 20 AND 35 DEGREES BELOW ZERO. IT/S LOOKING MORE AND MORE LIKELY THAT WIND CHILL ADVISORIES/WARNINGS WILL BE NEEDED. AFTER TEMPS BOTTOM OUT MON NIGHT...THE HIGH PRES CENTER WILL PUSH OFF TO THE E...ALLOWING A MORE SOUTHERLY FLOW. THIS WILL ALLOW HIGHS ON TUE TO CLIMB INTO THE SINGLE DIGITS ABOVE ZERO. && .AVIATION.../06Z TAF ISSUANCE/ MAIN FORECAST CONCERN THIS TAF PERIOD IS THE POTENTIAL FOR MVFR CIGS TO MOVE INTO THE AREA FROM THE NORTHWEST OVERNIGHT AND THURSDAY MORNING. 11-3.9 MICRON SATELLITE IMAGERY SHOWS A BLOB OF LLVL MOISTURE OVER NORTH DAKOTA ALONG THE WESTERN PERIPHERY OF THE SURFACE RIDGE. BOTH THE HRRR /CLOUDBASE/ AND RAP /925-850MB MOISTURE/ PROGS SHOW THIS AREA OF MOISTURE BETWEEN 2000 AND 4000 FT ADVECTING INTO THE MN BETWEEN 08Z AND 12Z...AND WI ON THURSDAY MORNING. WILL RETAIN A SCT-BKN MVFR LEVEL DECK IN THE TAF ACCORDINGLY. THE 925MB LAYER IS PROGGED TO DRY OUT THURSDAY AFTERNOON /MN/ AND EARLY EVE /WI/...BUT QUICKLY BE REPLACED BY A WEST TO EAST SURGE OF 850-700MB MOISTURE BETWEEN 03Z AND 12Z FRIDAY. WILL INTRODUCE SNOW INTO KAXN AROUND 03Z FRIDAY...BUT ONSET FOR THE REMAINDER OF THE SITES WILL MOST LIKELY BE BEYOND THIS TAF PERIOD. NORTHWEST WINDS AT 5 TO 10 KTS WILL PREVAIL THROUGH THE PERIOD. KMSP...SCT MVFR LEVEL CLOUDS /2000 FT/ WILL BE POSSIBLE AFTER 12Z THURSDAY...ALONG WITH A BKN VFR DECK /3500 FT/. THE 2KFT DECK COULD BRIEFLY GO BROKEN ON THURSDAY MORNING...BUT CONFIDENCE IS NOT HIGH ON THAT. CLEARING ENSUES IN THE AFTERNOON...WITH ANOTHER ROUND OF CLOUDS /LOW-END VFR CIGS/ ARRIVING AFTER 06Z FRIDAY. /OUTLOOK FOR KMSP/ FRI...VFR. CHC OF -SN AND MVFR VIS/CIG IN MORNING. WIND SW 5-15 KTS. SAT...MVFR CIGS LIKELY. AFTERNOON -SN POSSIBLE. W WIND 5 KTS BECOMING NW 15-20 KTS WITH GUSTS TO 30 KTS. SUN...CHANCE OF -SN WITH MVFR OR LOWER CIG/VIS. WINDS W 5-10 KTS BECOMING NW 15-20 KTS LATE. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ JPC/LS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
906 PM MST WED JAN 16 2013 .SHORT TERM...VALID FOR THU AND FRI... A WEAK COLD FRONT WAS APPROACHING THE FORECAST AREA FROM NE MT/W N DAKOTA THIS EVENING. MODELS INDICATED SOME WARM ADVECTION INCREASING OVER THIS BOUNDARY LATER TONIGHT. MOISTURE WAS ALREADY IN PLACE OVER SE MT PER SATELLITE IMAGERY AND SURFACE OBSERVATIONS. RAP AND WRF SOUNDINGS SUPPORTED FLURRIES AFTER 06Z AROUND KBHK. RADAR AND OBSERVATIONS WERE DRY THIS EVENING SO HAVE REMOVED THE FLURRIES THROUGH 06Z...BUT KEPT THEM GOING OVERNIGHT. TEMPERATURES WERE IN THE UPPER 20S AND 30S ACROSS THE AREA AT 03Z. MIN TEMPERATURES LOOKED REASONABLE FROM KBIL TO KSHR W...BUT SEEMED A BIT LOW OVER THE EASTERN ZONES. EVEN THOUGH COLD FRONT MOVES INTO THE E LATER TONIGHT...AIRMASS WILL NOT BE MUCH COLDER THAN IT IS CURRENTLY...AND CLOUD COVER WILL LIMIT TEMPERATURE FALLS. THUS HAVE RAISED THE MINS E OF KBIL. A TIGHT SURFACE PRESSURE GRADIENT WAS OVER THE AREA W OF KBIL THIS EVENING. WINDS OVER KLVM AND BIG TIMBER WERE IN THE 20S TO 30S MPH RANGE. GRADIENT WAS NOT EXPECTED TO TIGHTEN FURTHER OVERNIGHT...SO WILL NOT NEED A WIND ADVISORY. MODELS DID SHOW THE GRADIENT STRENGTHENING THU NIGHT...SO WIND HIGHLIGHTS WILL LIKELY BE NEEDED FOR THIS PERIOD THROUGH AT LEAST FRI. ARTHUR .LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED... EXTENDED MODELS REMAIN IN GOOD AGREEMENT THROUGH NEXT TUESDAY...WITH MAJOR DIFFERENCES APPEARING IN HOW THEY HANDLE A PACIFIC STORM SYSTEM THAT LOOKS TO IMPACT THE REGION BEGINNING LATE WEDNESDAY. NORTHWEST FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA SATURDAY INTO MONDAY AS MODELS STILL SHOW A DEEP UPPER LOW SITUATED OVER THE HUDSON BAY AREA AND UPPER LEVEL RIDGING OVER THE PACIFIC COAST. MODELS CONTINUE TO SHOW AN ARCTIC FRONT BACKDOORING INTO THE FAR EASTERN ZONES LATE IN THE DAY SATURDAY OR SATURDAY NIGHT. HOWEVER...CONFIDENCE IS STILL NOT HIGH AT THIS TIME AS TO THE TIMING OF THE FRONT NOR HOW FAR WEST IT WILL TRAVEL...ALTHOUGH IT DOES LOOK TO MAKE IT TO THE BILLINGS AREA. THE COLDEST AIR STILL LOOKS TO REMAIN FROM ABOUT ROSEBUD COUNTY EASTWARD WITH THE VERY BITTER COLD AIR REMAINING ACROSS NORTH DAKOTA. DID NOT MAKE ANY SIGNIFICANT CHANGES TO THE PREVIOUS FORECAST IN REGARDS TO TEMPERATURES FOR THE WEEKEND. AS FOR PRECIP...THERE STILL REMAINS THE POSSIBILITY OF SOME LIGHT SNOW ALONG THE FRONT AND IN THE ARCTIC AIRMASS ITSELF SUNDAY INTO SUNDAY NIGHT. THE ARCTIC AIR LOOKS TO BE SHORT-LIVED AS MODELS BRING THE UPPER LEVEL RIDGE OVER THE WEST COAST SLOWLY EASTWARD LATE MONDAY INTO EARLY WEDNESDAY. AT THE SAME TIME...SURFACE HIGH PRESSURE SOUTHWEST OF THE REGION COMBINES WITH SHORTWAVES IN NW FLOW TO TIGHTEN THE PRESSURE GRADIENT ACROSS THE WEST AND ONCE AGAIN INCREASE WINDS IN THE WESTERN FOOTHILLS. ALTHOUGH IT IS DEEP INTO THE EXTENDED...THE MODELS HAVE HAD THIS SCENARIO PLAYING OUT FOR SEVERAL CYCLES...SO CONFIDENCE IS INCREASING IN ANOTHER POTENTIAL HIGH WIND EVENT LATE MONDAY INTO AT LEAST TUESDAY NIGHT. BECAUSE OF THIS...INCREASED WIND GUSTS TO ABOUT 45 MPH FROM LIVINGSTON TO BIG TIMBER SOUTH TO NYE ALONG THE BEARTOOTH FOOTHILLS. IT DOES LOOK LIKE A WARM UP IS IN STORE MONDAY INTO EARLY WEDNESDAY AS THE UPPER LEVEL RIDGING MOVES CLOSER...THE DOWNSLOPE WINDS KICK IN AND THE ARCTIC AIR RETREATS TO THE EAST...SO ABOVE AVERAGE TEMPS ARE LOOKING MORE LIKELY DURING THAT PERIOD. THE NEXT PACIFIC SYSTEM MAY IMPACT THE REGION BEGINNING LATE WEDNESDAY. TIMING AND STRENGTH OF THIS SYSTEM HAVE YET TO BE DETERMINED...SO I MAINLY JUST TWEAKED POPS IN THE MOUNTAINS AND FOOTHILLS. STC && .AVIATION... VFR CONDITIONS CAN BE EXPECTED THROUGH THE NIGHT WITH JUST SOME MID LEVEL CLOUDS WORKING FROM NORTHWEST TO SOUTHEAST ACROSS SOUTHERN MONTANA AND NORTHERN WYOMING. GUSTY SOUTHWEST WINDS UP TO 30KTS WILL TAKE PLACE AT KLVM. THESE WINDS WILL INCREASE IN STRENGTH THURSDAY AFTERNOON AND NIGHT. TWH && .PRELIMINARY POINT TEMP/POPS... THU FRI SAT SUN MON TUE WED ----------------------------------------------------------- BIL 025/041 031/049 022/036 012/026 008/030 017/037 026/038 00/N 00/N 00/B 03/S 21/B 10/N 01/B LVM 027/044 028/045 023/039 014/030 011/032 019/036 023/036 00/N 00/N 00/N 02/S 21/N 10/N 02/J HDN 022/043 020/048 019/034 009/023 006/026 014/036 022/037 00/U 00/N 00/B 13/S 21/B 10/B 01/B MLS 022/038 020/045 015/024 003/016 904/017 009/029 019/032 00/U 00/B 00/B 13/S 21/B 10/B 01/B 4BQ 021/040 020/046 015/028 006/021 002/021 010/032 018/034 00/U 00/B 00/B 13/S 21/B 10/B 01/B BHK 020/036 023/040 013/021 001/013 909/013 004/025 016/030 10/B 00/B 00/B 13/S 11/B 11/B 01/B SHR 018/046 021/051 016/038 011/027 006/030 016/039 021/038 00/U 00/B 00/B 12/S 21/B 10/B 01/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
333 PM CST THU JAN 17 2013 .SHORT TERM...TONIGHT THROUGH SUNDAY MAIN FORECAST PROBLEM IS TEMPS AND WINDS WITH THE STRONG COLD FRONT ON SATURDAY AND ANOTHER FRONT SUNDAY/SUNDAY NIGHT. HOWEVER THE INITIAL ISSUE IS THE PERSISTENT AREA OF FOG AND STRATUS THAT REMAINED JUST EAST OF OMAHA THROUGHOUT THE DAY...BUT AFTERNOON VISIBLE LOOP SHOWS THAT AREA IS FINALLY ERODING WITH THE HELP OF AFTERNOON WARMING AND A WEST COMPONENT TO THE CLOUD TOP WINDS. AS TO WHETHER OR NOT THIS FOG/STRATUS WILL FORM AGAIN TONIGHT...WE BELIEVE THE STRENGTHENING WESTERLY 850MB WINDS SHOULD KEEP THE LAYER MIXED ENOUGH TO PREVENT REFORMING AND SOME WARMING IN THE LAYER SHOULD HELP AS WELL. ASSUMING FRIDAY STARTS WITHOUT THE STRATUS DECK...THE WESTERLY 850 WINDS WILL INFLUENCE A FAIRLY QUICK WARM UP THROUGHOUT THE MORNING AND HIGHS SHOULD REACH THE 50S MOST AREAS. THOSE LOCATIONS WHERE AN INCH OR MORE OF SNOW REMAINS WILL BE A FEW DEGREES COOLER...WHICH IS MAINLY WEST AND NORTH OF LINCOLN INTO THE FREMONT AREA. ON FRIDAY THE MAIN UPPER JET REMAINS WELL NORTH OF THE FORECAST AREA... HOWEVER A STRENGTHENING NORTHWEST FLOW JET MAX IS FORECAST TO BE MOVING THROUGH SOUTHERN ALBERTA/SASKATCHEWAN WHICH QUICKLY PUSHES ARCTIC AIR SOUTH THROUGH THE PLAINS. MODELS ARE IN GOOD AGREEMENT WITH THE TIMING AND STRENGTH OF THE COLD FRONTAL PASSAGE ACROSS OUR AREA SATURDAY. BEFORE THE FRONT MOVES THROUGH ON SATURDAY...THE AIRMASS WILL AGAIN SUPPORT WARM TEMPERATURES IN THE 40S BUT SOME CLOUD COVER WILL LIMIT WARMING. BEHIND THE FRONT NORTHWEST WINDS WILL INCREASE CONSIDERABLY WITH GUSTS OF 30 MPH AND SHARPLY FALLING TEMPERATURES. THE AIRMASS WILL REMAIN TOO DRY FOR ANY PRECIPITATION WITH THIS SYSTEM. BY SUNDAY A 1032+ SURFACE HIGH BUILDS IN WITH HIGHS MOSTLY IN THE 20S. ALSO ON SUNDAY THE UPPER RIDGE ALONG THE WEST COAST IS PROGGED TO AMPLIFY AND THUS PUSH ANOTHER COLD FRONT THROUGH THE PLAINS...THIS TIME FOLLOWED BY A STRONGER SURFACE HIGH OF AROUND 1040MB. NAM AND GFS ARE IN FAIR AGREEMENT ON THE TIMING OF THE SUNDAY FRONT BUT THE 12Z ECMWF IS A BIT SLOWER. EITHER WAY WE WILL SEE ANOTHER SURGE OF ARCTIC AIR AND COLDER TEMPERATURES. WIND CHILLS COULD DROP INTO THE MINUS 15 TO MINUS 20 DEGREE RANGE LATE SUNDAY NIGHT AND MONDAY MORNING ESPECIALLY IN NORTHEAST NEBRASKA. ONE FACTOR THAT WILL HELP KEEP TEMPERATURES FROM PLUMMETING WELL BELOW ZERO WITH THESE ARCTIC BLASTS WILL BE THE LACK OF SNOW COVER. HOWEVER COMPARED TO THE WARM DAYS LEADING UP TO SUNDAY...THE CHANGE IN TEMPERATURES AND WIND CHILLS WILL SURELY HAVE AN IMPACT ON THE REGION. NIETFELD .LONG TERM...SUNDAY NIGHT THROUGH THURSDAY MAIN CONCERN CONTINUES TO BE TEMPERATURES THROUGH THE PERIOD. ARCTIC AIRMASS IS STILL PROGGED TO PUSH INTO THE AREA THIS WEEKEND...WITH REINFORCING COLD AIR ON SUNDAY NIGHT/MONDAY. CWA WILL BE ON THE WESTERN FRINGE OF THE COLDEST AIR...AND LACKING IN SNOWPACK...BUT STILL COULD SEE TEMPS FALL INTO THE SINGLE DIGITS BELOW TO SINGLE DIGITS ABOVE ZERO...WITH RECOVERY INTO THE LOWER TEENS TO LOWER 20S ON MONDAY. MODERATING TEMPERATURES WILL THEN CONTINUE THROUGH AT LEAST WEDNESDAY NIGHT AS UPPER-LEVEL RIDGE MOVES OVERHEAD AND LOW-LEVEL SOUTHWEST FLOW CONTINUES. BY WEDNESDAY NIGHT/THURSDAY...ECMWF AND GFS BOTH INDICATE A STORM SYSTEM MOVING OUT OF THE ROCKIES AND ACROSS THE PLAINS. GFS AND 00Z ECMWF KEPT PRECIP EAST OF THE CWA...WHILE 12Z ECMWF IS A LITTLE SLOWER AND DEEPER AND DOES PLACE CWA IN A MORE FAVORABLE LOCATION FOR PRECIP. FOR NOW...BLENDS WERE DRY AND BELIEVE THAT IS THE WAY TO LEAN UNTIL MODELS DEVELOP SOME CONSISTENCY WITH THE THURSDAY SYSTEM. COLD AIR WILL SPILL IN AGAIN BEHIND THE SYSTEM...BEGINNING SOMETIME AROUND THURSDAY. MAYES && .AVIATION... 18Z TAFS FOR KOMA...KOFK...KLNK INITIAL CONCERN WILL BE HOW THE STRATUS WILL AFFECT KOMA NOW THAT IT IS MOVING OUT OF KLNK AND IS TO THE EAST OF KOFK. THE RAP SEEMS TO BE HANDLING THE STRATUS THE BEST...ALTHOUGH MAY NOT BE EXTENSIVE ENOUGH WITH THE WEAK FLOW. IFR CONDITIONS HAVE SPREAD INTO MLE AND WITH THE LIGHT NORTHEAST DRIFT OF THE DECK...DID BRING THE DECK IN KOMA THROUGH 00Z. WILL NEED TO MONITOR THIS AFTERNOON UNTIL EARLY EVENING TO SEE HOW MUCH THE AREA IS ABLE TO SHRINK DURING THE AFTERNOON. AFTER 03Z...THE LOW LEVEL JET STRENGTHENS AND HAVE ADDED TO ALL THREE TAF FORECASTS. THIS SHOULD HINDER ANY LOW CLOUDS DEVELOPMENT. ZAPOTOCNY && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1159 AM CST THU JAN 17 2013 .UPDATE... WILL CONTINUE TO MAKE SHORT TERM UPDATES TO BETTER ACCOUNT FOR STRATUS AND TEMPERATURES. && .DISCUSSION... CLOUDS AND TEMPERATURES TO BE QUITE VARIABLE TODAY. UPDATED THE PUBLIC FORECAST TO LOWER TEMPERATURES WHERE STRATUS AND FOG WILL HOLD ON LONGER. FLOW IS WEAK...BUT TENDENCY IS TO SHIFT EAST WITH TIME. LOCATIONS TOWARD ALBION HAVE WARMED QUICKLY INTO THE 40S WITH A LITTLE BETTER MIXING. && .AVIATION... 18Z TAFS FOR KOMA...KOFK...KLNK INITIAL CONCERN WILL BE HOW THE STRATUS WILL AFFECT KOMA NOW THAT IT IS MOVING OUT OF KLNK AND IS TO THE EAST OF KOFK. THE RAP SEEMS TO BE HANDLING THE STRATUS THE BEST...ALTHOUGH MAY NOT BE EXTENSIVE ENOUGH WITH THE WEAK FLOW. IFR CONDITIONS HAVE SPREAD INTO MLE AND WITH THE LIGHT NORTHEAST DRIFT OF THE DECK...DID BRING THE DECK IN KOMA THROUGH 00Z. WILL NEED TO MONITOR THIS AFTERNOON UNTIL EARLY EVENING TO SEE HOW MUCH THE AREA IS ABLE TO SHRINK DURING THE AFTERNOON. AFTER 03Z...THE LOW LEVEL JET STRENGTHENS AND HAVE ADDED TO ALL THREE TAF FORECASTS. THIS SHOULD HINDER ANY LOW CLOUDS DEVELOPMENT. && .PREV DISCUSSION... /ISSUED 156 AM CST THU JAN 17 2013/ DISCUSSION... IMPENDING DRY ARCTIC BLAST THIS WEEKEND CONTINUES TO BE MAIN ISSUE. GOING FCST IS IN VERY GOOD SHAPE AND ONLY MINOR TWEAKS NEEDED. LARGE SCALE FLOW OVER THE NEXT SEVERAL DAYS WILL MAKE POSSIBLE A DRAMATIC SHIFT IN TEMPERATURES THIS WEEKEND AND EARLY NEXT WEEK. MODELS IN AGREEMENT AMPLIFYING WRN CONUS UPPER LEVEL RIDGE AND BROAD LONGWAVE TROF DOWNSTREAM WILL ALLOW THE COLDEST AIR MASS OF THE SEASON TO DROP OUT OF CANADA AND INTO THE LOWER 48. MODELS CONTINUE TO ADVERTISE INITIAL THRUST OF CAA WILL BE UNDERWAY EARLY SAT MORNING IN ASSOCIATION WITH DEEP SFC LOW DROPPING DOWN THRU THE UPPER MIDWEST. TIME-SECTIONS PRETTY MUCH SHOWING LEADING EDGE OF THE BNDRY SHOULD BE PASSING THRU THE OMAHA METRO SHORTLY BEFORE AFTN. SUN NIGHT/MON...REINFORCING SHOT OF INTENSE CAA IS THEN PROGGED TO DROP INTO THE CNTRL PLAINS. AS USUAL WITH INTENSE THERMAL ADVECTION MEX AND ECM MOS NUMBERS ARE OFF...AND IN THIS CASE TOO WARM. AT THIS POINT STILL THINK MONDAY LOWS WILL BOTTOM OUT AROUND 5-10 ABOVE WITH WIND CHILL INDICES RANGING -10 TO -20 BELOW WHILE HIGHS WILL STRUGGLE TO REACH THE MID/UPPER TEENS. FORTUNATELY...THE BITTERLY COLD CONDITIONS WILL BE SHORT LIVED AND WITH TEMPS REBOUNDING WED/THURS WITH HIGHS GENERALLY IN THE U30S/M40S AFOREMENTIONED WRN RIDGE BUILDING EAST AND INCREASING THKNS SPREADING OVER THE PLAINS. DEE && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1250 AM EST THU JAN 17 2013 .SYNOPSIS... THE STORM SYSTEM THAT BROUGHT THE SNOW TO THE AREA TODAY HAS EXITED OFF OF THE EAST COAST. A COLD FRONT WILL CROSS THE AREA ON THURSDAY BRINGING SCATTERED SNOW SHOWERS AND DROPPING TEMPERATURES DURING THE AFTERNOON. BRIEFLY MILDER TEMPERATURES SATURDAY...WILL BE REPLACED BY MUCH COLDER AIR EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 7 PM UPDATE... JUST MINOR TWEAKS TO HRLY T/TD GRIDS AT THIS TIME AS THEY APPEAR TO BE RIGHT ON TARGET. SNOW HAS EXITED THE REGION TO THE EAST WITH DRY AIR WORKING DOWN WELL INTO THE BL, LEAVING VRY LITTLE CHC FOR LINGERING FZRA OR FZDZ. THUS POPS HV BEEN DROPPED TO ZERO UNTIL COLD FRNT INCHES CLOSER. LIGHT SNOW IS OCCURRING ACRS SRN ONTARIO AND CANADIAN RADARS INDICATE THIS AREA OF PCPN ABOUT READY TO ENTER OVR LK ONTARIO. 18Z NAM AND LATEST HRRR HAS FAIRLY GOOD HANDLE ON PCPN LOCATION AND HV USED MODEL BLENDS TO ACCNT FOR TRENDS DRG THE OVRNGT PD. TIMING ON FRONT BRINGS IT INTO FINGER LKS REGION BY 12Z WHICH IS IN LINE WITH THE NAM12. SLGT CHC POPS ENTER INTO EXTRM NRN ZONES BY 03Z AND SPREAD INTO TWIN TIERS BY 12Z. AS LK MOISTURE IS PICKED UP, HICHC TO LKLY POPS EXPECTED ARND 12Z AS SATURATED LYR INCREASES TO NR 800MB AND MEAN FLOW SETTLES OUT ARND 280 DEGREES. SNOWFALL AMNTS ACRS ONEIDA CNTY THRU 12Z THURSDAY WILL BE ARND 1 INCH. SKIES HV CLRD ACRS PORTIONS OF THE CWA AS OF 00Z AND WL DROP SOUTH TONIGHT AS DRY AIR MVS IN BHND SYSTEM AND AHD OF APPCHG FRONTAL BNDRY. THUS HV UPDATED SKY GRIDS TO ACCNT FOR THIS TREND AND MAY IMPACT AMNT OF TEMP DROP WITH SNOWPACK IN PLACE ONCE AGAIN. PREV DISCO BLO... 3 PM UPDATE... LINGERING LIGHT PRECIP WILL MOVE OUT BY 7 PM. WITH LOW LEVEL SATURATION NOT GOING INTO THE DENDRITE ZONE, FREEZING RAIN AND FREEZING DRIZZLE IS POSSIBLE. DRIER AIR WILL MOVE IN SLOWLY FROM THE WEST. THE BACK EDGE NOW FROM FZY TO DSV. QUIET THIS EVENING BEFORE A COLD FRONT DROPS SE THROUGH THE CWA LATE TONIGHT AND THU MORNING. SOME MOISTURE BUT SNOW SHOWERS WILL BE LIGHT. 6 HOUR SNOWFALL AMOUNTS UNDER AN INCH. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/... 3 PM UPDATE... WITH THE COLD FRONT THURSDAY HIGHS WILL BE IN THE MORNING WITH CENT NY DROPPING IN THE AFTN. LAKE EFFECT WILL KICK IN BUT SHOULD REMAIN WEAK INTO FRIDAY. SHEAR IS HIGH. THE SATURATED LEVEL IS ONLY TO 5K TO START THEN LIFTS TO 7 THU NGT. A SHALLOW DENDRITE ZONE AT THE TOP OF THE SATURATED LAYER WILL ALSO LIMIT SNOWFALL THU. THU NGT LAKE EFFECT SHOULD BE BETTER BUT NW FLOW WILL MEAN MULTIBANDS AND NO LAKE HURON CONNECTION. COLDER WITH BETTER MOISTURE. THE COLDER AIR BRINGS THE DENDRITE ZONE DOWN SOLIDLY IN THE DENDRITE ZONE. STILL A LOT OF SHEAR WITH HARDLY ANY SFC TO 2K WINDS. FRI AFTN INTO SAT THE LOW LEVEL WINDS SHIFT TO WEST SENDING THE LAKE EFFECT INTO JUST ONEIDA. WAA STARTS KILLING THE LAKE EFFECT FRI NGT, BUT NOT SOON ENOUGH TO GET FRI HIGH TEMPS ABOVE FREEZING. HIGH PRESSURE SLIDES EAST FROM THE OHIO VALLEY FRI INTO THE CAROLINAS FRI NGT. A WARM FRONT AHEAD OF A SFC LOW MOVING EAST IN SE CANADA WILL BRING SNOW SHOWERS ALONG THE LAKE SHORE LATE FRI AND FRI EVE. LOW LEVEL FLOW CONTINUES OUT OF THE W AND SW SATURDAY SO MOST OF THE CWA WILL BE DRY. WITH 850MB TEMPS APPROACHING ZERO HIGH TEMPS WILL RISE INTO THE U30S AND L40S. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... 230 PM WED UPDATE... HIGH CONFIDENCE IN AN ARCTIC SHIFT TO THE WEATHER PATTERN WITH PERHAPS THE COLDEST AIR OF THE SEASON EN ROUTE. GFS AND ECMWF AGREE ON 1000-500MB THICKNESSES DIPPING IN THE 490S FOR AT LEAST CENTRAL NY AND CLOSE TO IT FOR NORTHEAST PA BY 12Z TUESDAY. THIS BEGINS WITH INITIAL MOISTURE-LIMITED COLD FRONT PASSING THROUGH EARLY SUNDAY WITH SOME SCATTERED SNOW SHOWERS...BRINGING TEMPERATURES BACK TO NEAR NORMAL. ARCTIC FRONT THEN DROPS THROUGH MONDAY TO SEND TEMPERATURES WELL BELOW CLIMATOLOGY EARLY NEXT WEEK. LAKE EFFECT DETAILS AND PRESENCE OF CLIPPER-LIKE SYSTEMS WITHIN BRISK UPPER FLOW HAVE YET TO BE SORTED OUT...YET VERY DRY AIR MASS OVERALL...SO FOR NOW WENT ALONG WITH HPC POPS GENERALLY IN SLIGHT TO LOW CHANCE RANGE /POPS HIGHEST WITH ARCTIC FRONT MONDAY IN 30-50 PCT RANGE/. WITH 850MB TEMPERATURES PUSHING AROUND MINUS-20 CELSIUS BY TUESDAY...JUST ABOUT ANY PASSING CLOUD WILL AT LEAST PRODUCE LIGHT SCATTERED FLURRIES WITH ABOUT THE SAME WATER CONTENT AS STYROFOAM. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... ARCTIC FNT WILL DROP THRU THE AREA AFT 12Z AND TRIGGER SOME SNOW SHWRS WITH A BRIEF PD OF LE BHD THE FNT. THIS WILL DROP CIGS AND VSBYS INTO THE MVFR RANGE MOST STATIONS...WITH SOME BRIEF IFR CONDS PSBL. WLY WINDS HAD OF THE FNT WILL BECOME NLY BHD THE FNT...THEN BECOME LGT AFT 00Z AS HIPRES BLDS IN. .OUTLOOK... THU NGT THRU FRI...MAINLY MVFR CIGS AND SOME SCT -SHSN IN CNTRL NY...VFR AVP. FRI NGT/SAT...MAINLY VFR. SAT NGT THRU MON...MVFR/IFR IN SNOW SHOWERS...ESPECIALLY CNTRL NY. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...MDP/PVN NEAR TERM...PVN/TAC SHORT TERM...TAC LONG TERM...MDP AVIATION...DGM/DJP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 PM EST THU JAN 17 2013 .SYNOPSIS... STRENGTHENING LOW PRESSURE OVER UPSTATE SOUTH CAROLINA WILL TRACK TO THE EAST NORTHEAST ACROSS SOUTHEAST NORTH CAROLINA THIS EVENING... THEN OFF THE COAST LATE TONIGHT. COLD HIGH PRESSURE WILL BUILD IN FROM THE WEST FRIDAY INTO THE WEEKEND. && .NEAR TERM /THROUGH FRIDAY/... AS OF 150 PM THURSDAY... THROUGH TONIGHT: CONFIDENCE REMAINS HIGH IN THE OCCURRENCE OF SIGNIFICANT BANDED SNOWFALL OVER NRN AND WRN PORTIONS OF NC EARLY THIS EVENING THROUGH TONIGHT. INTENSIFYING SURFACE LOW PRESSURE... LOCATED OVER NE GA EARLY THIS AFTERNOON... WILL CONTINUE A STEADY ENE TRACK ALONG A FRONTAL ZONE ACROSS SE NC. THE NAM/GFS/RAP/SREF MEAN HAVE EXHIBITED EXCELLENT CONTINUITY THE LAST SEVERAL RUNS REGARDING TRACK AND TIMING... AND HAVE SHOWN A VERY SMALL SOUTHWARD TREND IN THE EXTENT OF COLDER AIR. DYNAMIC LIFT WITH THIS SYSTEM WILL BE EXTREMELY STRONG -- ESPECIALLY ALOFT WITH HIGH OMEGA FOCUSED IN THE CRUCIAL -12C TO -20C LAYER ALOFT -- BUT QUICK-HITTING. AN INTENSE UPPER DIVERGENCE MAX EXPECTED TO BE ROUGHLY OVER THE SRN NC FOOTHILLS AT 00Z WILL MOVE NE THROUGH CENTRAL NC BEFORE EXITING NE SECTIONS OF THE CWA BY AROUND 07Z. THIS IS IN TANDEM WITH THE PASSAGE OF STRONG Q-VECTOR CONVERGENCE... MID LEVEL DCVA AND A RISE/FALL COUPLET OF AROUND +/- 200 METERS... STRONG LOW LEVEL THETA-E ADVECTION... AND DEEP MOIST ISENTROPIC UPGLIDE. THE FACT THAT THIS SYSTEM IS STRENGTHENING QUICKLY UPON ARRIVAL IS ESPECIALLY TROUBLING IN THAT THE RESULTANT RAPID MASS FIELD ADJUSTMENTS ARE LIABLE TO SIGNIFICANT AND QUICKLY BOLSTER ASCENT AND HEIGHTEN THE EXTENT AND INTENSITY OF THE SNOW BANDING. MOISTURE AVAILABILITY WILL GENERALLY NOT BE A PROBLEM WITH VERY HIGH PW (OVER 200 PERCENT OF NORMAL) AND A STRONG MOISTURE TRANSPORT FROM THE GULF... ALTHOUGH THE INCOMING DRY SLOT ON THE SE SIDE OF THE LOW WILL BE WORTH MONITORING AND MAY LIMIT WINTRY TOTALS IN THE SOUTHEAST CWA (SEE BELOW). HOW FAST THE COLD AIR ARRIVES ESPECIALLY ALOFT REMAINS A CONCERN... ALTHOUGH THE MODELS INITIALIZED WELL AND ARE IN VERY GOOD AGREEMENT... BOOSTING CONFIDENCE IN THEIR TIMING OF THE ANTICIPATED THERMAL CHANGES. THE HEAVIEST SNOW BANDING IS LIKELY TO OCCUR OVER THE WRN AND NRN PIEDMONT... FROM HIGH ROCK AND BADIN LAKES... ACROSS THE I-40 AND HIGHWAY 64 CORRIDORS BETWEEN (AND INCLUDING) THE TRIAD AND THE TRIANGLE... UP TO KERR LAKE AND LAKE GASTON... VERY ROUGHLY FOLLOWING THE I-85 CORRIDOR TO THE NW... ALIGNED WITH THE AREA OF STRONGEST DEFORMATION ALOFT. KEY TIMING STILL LOOKS TO BE FROM 23Z UNTIL AROUND 07Z WITH A QUICK EXIT SOON THEREAFTER. SREF PROBABILITIES HAVE BEEN VERY CONSISTENT IN SHOWING A 70+ PERCENT CHANCE OF SNOWFALL RATES OVER ONE INCH PER HOUR ACROSS MUCH OF THE PIEDMONT AND FAR NRN COASTAL PLAIN FROM MID EVENING UNTIL THE EARLY OVERNIGHT HOURS. WITH THESE RATES AND THE TIMING OF A FEW HOURS OF HEAVY BANDED SNOW (STARTING AS A RAIN/SNOW MIX)... STORM TOTAL ACCUMULATIONS OF 2-4 INCHES IN THIS AREA WITH ISOLATED 5 INCH TOTALS LOOK QUITE REASONABLE. BORDERING THE WARNING AREA... STILL EXPECT AN INCH OR SO OF ACCUMULATION MAINLY ON GRASSY AREAS... WITH A LITTLE SLUSH ON ROADS POSSIBLE. SOUTH AND EAST OF HERE... INCLUDING FAYETTEVILLE AND CLINTON... A QUICK BURST OF MAINLY SNOW IS POSSIBLE WITH STRONG DYNAMIC COOLING THROUGH THE COLUMN AS THE LOW ALOFT PASSES BY... BUT THE WINDOW OF OPPORTUNITY WILL BE VERY SHORT AS AMOUNTS/DURATION WILL BE GREATLY LIMITED BY THE MID-UPPER LEVEL DRY SLOT ARRIVAL WITH NOTABLE DRYING ABOVE THE -5C LEVEL... SUPPRESSING CRYSTAL GROWTH ALOFT... PLUS BOUNDARY LAYER TEMPS SHOULD HOLD ABOVE FREEZING FOR MUCH OF THIS EVENT... NOT DROPPING TO NEAR FREEZING UNTIL PRECIP IS NEARLY GONE. EXPECT LIGHT ACCUMULATIONS OF A DUSTING CONFINED TO GRASSY AREAS. A SIDE NOTE: MID LEVEL LAPSE RATE PROGS ARE QUITE INTERESTING... INCLUDING THE 12 KM NAM WHICH INDICATES 850-500 MB VALUES OF 5.5-6.0 C/KM TRAVERSING THE CWA... JUST WNW OF THE 850 MB LOW TRACK... PRIMARILY BETWEEN 03Z AND 06Z. AND RECENT RAP RUNS TAKE THE 700-400 MB LAPSE RATES (WHICH CAPTURES THE MIXED PHASE REGION ALOFT) UP TO 7.0 C/KM OVER THE NW PIEDMONT TOWARD MIDNIGHT. CONSIDERING THIS POSSIBILITY FOR UPRIGHT INSTABILITY COMBINED WITH VIGOROUS DYNAMIC LIFT... A FEW LIGHTNING STRIKES WITHIN SNOW BANDS ARE CERTAINLY POSSIBLE... ALTHOUGH LIKELY TOO ISOLATED TO INCLUDE IN THE FORECAST AT THIS TIME. STRENGTHENING WINDS WILL BE AN ISSUE AS WELL WITH THE TIGHTENING MSLP GRADIENT AS THE LOW APPROACHES. WE ARE ALREADY SEEING FREQUENT GUSTS TO 25-40 KTS (ALTHOUGH SOME OF THIS MAY BE AUGMENTED BY A POSSIBLE GRAVITY WAVE). EXPECT A PERIOD OF SUSTAINED WINDS OF 15-25 MPH WITH SPORADIC GUSTS TO AROUND 30 MPH FROM LATE AFTERNOON UNTIL AROUND 1-2 AM. TEMPS SHOULD STEADILY DROP THROUGH THE REST OF THE AFTERNOON AND NIGHT. FOR FRIDAY: EXPECT GENERALLY CLEAR SKIES BY DAYBREAK AS THE STORM DEPARTS QUICKLY WITH CHILLY HIGH PRESSURE BUILDING IN FROM THE WEST. FORECAST SOUNDINGS AND UPSTREAM CONDITIONS SUGGEST THAT TEMPS SHOULD STRUGGLE TO RISE TOMORROW WITH STRONG COLD AIR ADVECTION IN THE MORNING... AND THICKNESSES THAT HOLD AT OR BELOW 1305 METERS ALL DAY (AND THIS IS EVEN TAKING INTO ACCOUNT THE SHALLOW MIXING AND THAT THIS LAYER ENCOMPASSES THE SUBSIDENCE INVERSION ALOFT). HAVE BUMPED HIGHS DOWN TO 36-45. WINDS SHOULD DIMINISH DURING THE AFTERNOON. -GIH && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... AS OF 240 PM THURSDAY... A 1032MB HIGH PRESSURE WILL SETTLE OVERHEAD FRIDAY NIGHT...ALLOWING FOR GOOD RADIATIONAL COOLING UNDER CLEAR SKIES. THERE MAY BE SOME SHADED AREAS WHERE SNOW COVER IS ABLE TO LINGER THROUGH THE DAY FRIDAY...WHICH MAY HELP RADIATIONAL COOLING IN A FEW SPOTS...BUT OVERALL GUIDANCE SUPPORTS LOWS IN THE MID 20S. THE UPPER LEVEL FLOW WILL REMAIN RELATIVELY FLAT SATURDAY WHILE THE SURFACE HIGH SHIFTS SLIGHTLY SOUTHWARD. THE SHALLOW COOLER AIRMASS WILL ONLY SLIGHTLY MODIFY WITH WEAK VERTICAL MIXING...LEADING TO HIGHS IN THE MID 40S TO LOWER 50S. LOWS SATURDAY NIGHT IN THE UPPER 20S TO LOWER 30S && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 240 PM THURSDAY... THE UPPER LEVEL PATTERN WILL BEGIN A SLOW AMPLIFICATION SUNDAY AS RIDGING BUILDS OUT WEST AND A DEEP TROUGH DEVELOPS OVER THE EASTERN US. A COLD NORTHWESTERLY FLOW WILL PERSIST THROUGH MIDWEEK... A COUPLE REINFORCING SHOTS OF ARCTIC AIR VIA DRY COLD FRONTS AS SHORTWAVES ROTATE SOUTHEAST OUT OF CANADA AND INTO THE BASE OF THE TROUGH. HIGHS AROUND NORMAL SUNDAY WILL FALL IN TO THE 40S MONDAY....AND THEN A MORE SIZABLE DROP TUESDAY AND THICKNESSES CRASH TO NEAR OR BELOW 1260M TUESDAY MORNING. BASED ON THESE THICKNESSES...LOWS COULD BE IN THE TEENS AND HIGHS IN THE LOW TO MID 30S. MODELS HAVE ONLY RECENTLY COME INTO BETTER AGREEMENT ON THESE THICKNESSES...AND THE LACK OF SNOW COVER OVER THE MIDWEST LEADS TO LOWER CONFIDENCE IN TEMPS BEING ON THE COLDER SIDE OF WHAT HAS HISTORICALLY BEEN OBSERVED. DURING THIS PERIOD...ALL CYCLOGENESIS ASSOCIATED WITH SHORTWAVES IN THE NORTHWEST FLOW ALOFT SHOULD STAY WELL OFFSHORE...WITH THE ONLY SENSIBLE IMPACT WILL BE POSSIBLE OROGRAPHIC CIRRUS MONDAY NIGHT OR TUESDAY NIGHT. BY THE END OF THE PERIOD...MODELS INDICATE THE WEST COAST RIDGE MAY WEAKEN AND ALLOW ENERGY TO CROSS INTO THE CENTRAL US AND BRING A BETTER CHANCE OF PRECIP LATE NEXT WEEK INTO THE WEEKEND. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 1250 PM THURSDAY... 24 HOUR TAF PERIOD: LIGHT TO MODERATE RAIN WILL CONTINUE OVER THE WRN HALF OF THE AREA AND SLOWLY MOVE EAST THIS EVENING AS THE SURFACE LOW TRACKS NE INTO CENTRAL NC. HIGH CONFIDENCE THAT IFR AND LIFR AVIATION CONDITIONS WILL CONTINUE THROUGH APPROX 12Z FRIDAY. RAIN WILL CHANGE TO SNOW FROM WEST TO EAST...WITH SOME UNCERTAINTY ON THE EXACT TIMING OF THE CHANGE OVER. FOR NOW HAVE SNOW STARTING AROUND 23Z AT KINT AND KGSO TO 02-04Z AT KRDU AND KRWI...WITH THE CHANCE FOR A BRIEF PERIOD OF SNOW AT KFAY AROUND 05Z FRIDAY. SNOW AND FOG WILL KEEP LIFR CONDITIONS IN PLACE THROUGH 05Z-06Z. RESIDUAL LOW LEVEL MOISTURE MAY KEEP VISBYS LOW EVEN AFTER THE SNOW ENDS. AVIATION CONDITIONS SHOULD IMPROVE TO VFR AROUND SUNRISE. NNE WINDS AROUND 10-20 KTS THIS EVENING WILL SHIFT TO THE NW AS THE FRONT MOVES THROUGH CENTRAL NC OVERNIGHT. LOOKING AHEAD: VFR CONDITIONS EXPECTED FRIDAY NIGHT THROUGH TUESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY FOR NC028-042-043-077-078-083-084. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY FOR NCZ007>011-021>027-038>041-073>076. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD SHORT TERM...SMITH LONG TERM...SMITH AVIATION...WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 PM EST THU JAN 17 2013 .SYNOPSIS... STRENGTHENING LOW PRESSURE OVER NORTHERN GEORGIA WILL TRACK TO THE EAST NORTHEAST ACROSS SOUTHEAST NORTH CAROLINA THIS EVENING... THEN OFF THE COAST LATE TONIGHT. COLD HIGH PRESSURE WILL BUILD IN FROM THE WEST FRIDAY INTO THE WEEKEND. && .NEAR TERM /THROUGH FRIDAY/... AS OF 150 PM THURSDAY... THROUGH TONIGHT: CONFIDENCE REMAINS HIGH IN THE OCCURRENCE OF SIGNIFICANT BANDED SNOWFALL OVER NRN AND WRN PORTIONS OF NC EARLY THIS EVENING THROUGH TONIGHT. INTENSIFYING SURFACE LOW PRESSURE... LOCATED OVER NE GA EARLY THIS AFTERNOON... WILL CONTINUE A STEADY ENE TRACK ALONG A FRONTAL ZONE ACROSS SE NC. THE NAM/GFS/RAP/SREF MEAN HAVE EXHIBITED EXCELLENT CONTINUITY THE LAST SEVERAL RUNS REGARDING TRACK AND TIMING... AND HAVE SHOWN A VERY SMALL SOUTHWARD TREND IN THE EXTENT OF COLDER AIR. DYNAMIC LIFT WITH THIS SYSTEM WILL BE EXTREMELY STRONG -- ESPECIALLY ALOFT WITH HIGH OMEGA FOCUSED IN THE CRUCIAL -12C TO -20C LAYER ALOFT -- BUT QUICK-HITTING. AN INTENSE UPPER DIVERGENCE MAX EXPECTED TO BE ROUGHLY OVER THE SRN NC FOOTHILLS AT 00Z WILL MOVE NE THROUGH CENTRAL NC BEFORE EXITING NE SECTIONS OF THE CWA BY AROUND 07Z. THIS IS IN TANDEM WITH THE PASSAGE OF STRONG Q-VECTOR CONVERGENCE... MID LEVEL DCVA AND A RISE/FALL COUPLET OF AROUND +/- 200 METERS... STRONG LOW LEVEL THETA-E ADVECTION... AND DEEP MOIST ISENTROPIC UPGLIDE. THE FACT THAT THIS SYSTEM IS STRENGTHENING QUICKLY UPON ARRIVAL IS ESPECIALLY TROUBLING IN THAT THE RESULTANT RAPID MASS FIELD ADJUSTMENTS ARE LIABLE TO SIGNIFICANT AND QUICKLY BOLSTER ASCENT AND HEIGHTEN THE EXTENT AND INTENSITY OF THE SNOW BANDING. MOISTURE AVAILABILITY WILL GENERALLY NOT BE A PROBLEM WITH VERY HIGH PW (OVER 200 PERCENT OF NORMAL) AND A STRONG MOISTURE TRANSPORT FROM THE GULF... ALTHOUGH THE INCOMING DRY SLOT ON THE SE SIDE OF THE LOW WILL BE WORTH MONITORING AND MAY LIMIT WINTRY TOTALS IN THE SOUTHEAST CWA (SEE BELOW). HOW FAST THE COLD AIR ARRIVES ESPECIALLY ALOFT REMAINS A CONCERN... ALTHOUGH THE MODELS INITIALIZED WELL AND ARE IN VERY GOOD AGREEMENT... BOOSTING CONFIDENCE IN THEIR TIMING OF THE ANTICIPATED THERMAL CHANGES. THE HEAVIEST SNOW BANDING IS LIKELY TO OCCUR OVER THE WRN AND NRN PIEDMONT... FROM HIGH ROCK AND BADIN LAKES... ACROSS THE I-40 AND HIGHWAY 64 CORRIDORS BETWEEN (AND INCLUDING) THE TRIAD AND THE TRIANGLE... UP TO KERR LAKE AND LAKE GASTON... VERY ROUGHLY FOLLOWING THE I-85 CORRIDOR TO THE NW... ALIGNED WITH THE AREA OF STRONGEST DEFORMATION ALOFT. KEY TIMING STILL LOOKS TO BE FROM 23Z UNTIL AROUND 07Z WITH A QUICK EXIT SOON THEREAFTER. SREF PROBABILITIES HAVE BEEN VERY CONSISTENT IN SHOWING A 70+ PERCENT CHANCE OF SNOWFALL RATES OVER ONE INCH PER HOUR ACROSS MUCH OF THE PIEDMONT AND FAR NRN COASTAL PLAIN FROM MID EVENING UNTIL THE EARLY OVERNIGHT HOURS. WITH THESE RATES AND THE TIMING OF A FEW HOURS OF HEAVY BANDED SNOW (STARTING AS A RAIN/SNOW MIX)... STORM TOTAL ACCUMULATIONS OF 2-4 INCHES IN THIS AREA WITH ISOLATED 5 INCH TOTALS LOOK QUITE REASONABLE. BORDERING THE WARNING AREA... STILL EXPECT AN INCH OR SO OF ACCUMULATION MAINLY ON GRASSY AREAS... WITH A LITTLE SLUSH ON ROADS POSSIBLE. SOUTH AND EAST OF HERE... INCLUDING FAYETTEVILLE AND CLINTON... A QUICK BURST OF MAINLY SNOW IS POSSIBLE WITH STRONG DYNAMIC COOLING THROUGH THE COLUMN AS THE LOW ALOFT PASSES BY... BUT THE WINDOW OF OPPORTUNITY WILL BE VERY SHORT AS AMOUNTS/DURATION WILL BE GREATLY LIMITED BY THE MID-UPPER LEVEL DRY SLOT ARRIVAL WITH NOTABLE DRYING ABOVE THE -5C LEVEL... SUPPRESSING CRYSTAL GROWTH ALOFT... PLUS BOUNDARY LAYER TEMPS SHOULD HOLD ABOVE FREEZING FOR MUCH OF THIS EVENT... NOT DROPPING TO NEAR FREEZING UNTIL PRECIP IS NEARLY GONE. EXPECT LIGHT ACCUMULATIONS OF A DUSTING CONFINED TO GRASSY AREAS. A SIDE NOTE: MID LEVEL LAPSE RATE PROGS ARE QUITE INTERESTING... INCLUDING THE 12 KM NAM WHICH INDICATES 850-500 MB VALUES OF 5.5-6.0 C/KM TRAVERSING THE CWA... JUST WNW OF THE 850 MB LOW TRACK... PRIMARILY BETWEEN 03Z AND 06Z. AND RECENT RAP RUNS TAKE THE 700-400 MB LAPSE RATES (WHICH CAPTURES THE MIXED PHASE REGION ALOFT) UP TO 7.0 C/KM OVER THE NW PIEDMONT TOWARD MIDNIGHT. CONSIDERING THIS POSSIBILITY FOR UPRIGHT INSTABILITY COMBINED WITH VIGOROUS DYNAMIC LIFT... A FEW LIGHTNING STRIKES WITHIN SNOW BANDS ARE CERTAINLY POSSIBLE... ALTHOUGH LIKELY TOO ISOLATED TO INCLUDE IN THE FORECAST AT THIS TIME. STRENGTHENING WINDS WILL BE AN ISSUE AS WELL WITH THE TIGHTENING MSLP GRADIENT AS THE LOW APPROACHES. WE ARE ALREADY SEEING FREQUENT GUSTS TO 25-40 KTS (ALTHOUGH SOME OF THIS MAY BE AUGMENTED BY A POSSIBLE GRAVITY WAVE). EXPECT A PERIOD OF SUSTAINED WINDS OF 15-25 MPH WITH SPORADIC GUSTS TO AROUND 30 MPH FROM LATE AFTERNOON UNTIL AROUND 1-2 AM. TEMPS SHOULD STEADILY DROP THROUGH THE REST OF THE AFTERNOON AND NIGHT. -GIH && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... AS OF 240 PM THURSDAY... A 1032MB HIGH PRESSURE WILL SETTLE OVERHEAD FRIDAY NIGHT...ALLOWING FOR GOOD RADIATIONAL COOLING UNDER CLEAR SKIES. THERE MAY BE SOME SHADED AREAS WHERE SNOW COVER IS ABLE TO LINGER THROUGH THE DAY FRIDAY...WHICH MAY HELP RADIATIONAL COOLING IN A FEW SPOTS...BUT OVERALL GUIDANCE SUPPORTS LOWS IN THE MID 20S. THE UPPER LEVEL FLOW WILL REMAIN RELATIVELY FLAT SATURDAY WHILE THE SURFACE HIGH SHIFTS SLIGHTLY SOUTHWARD. THE SHALLOW COOLER AIRMASS WILL ONLY SLIGHTLY MODIFY WITH WEAK VERTICAL MIXING...LEADING TO HIGHS IN THE MID 40S TO LOWER 50S. LOWS SATURDAY NIGHT IN THE UPPER 20S TO LOWER 30S && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 240 PM THURSDAY... THE UPPER LEVEL PATTERN WILL BEGIN A SLOW AMPLIFICATION SUNDAY AS RIDGING BUILDS OUT WEST AND A DEEP TROUGH DEVELOPS OVER THE EASTERN US. A COLD NORTHWESTERLY FLOW WILL PERSIST THROUGH MIDWEEK... A COUPLE REINFORCING SHOTS OF ARCTIC AIR VIA DRY COLD FRONTS AS SHORTWAVES ROTATE SOUTHEAST OUT OF CANADA AND INTO THE BASE OF THE TROUGH. HIGHS AROUND NORMAL SUNDAY WILL FALL IN TO THE 40S MONDAY....AND THEN A MORE SIZABLE DROP TUESDAY AND THICKNESSES CRASH TO NEAR OR BELOW 1260M TUESDAY MORNING. BASED ON THESE THICKNESSES...LOWS COULD BE IN THE TEENS AND HIGHS IN THE LOW TO MID 30S. MODELS HAVE ONLY RECENTLY COME INTO BETTER AGREEMENT ON THESE THICKNESSES...AND THE LACK OF SNOW COVER OVER THE MIDWEST LEADS TO LOWER CONFIDENCE IN TEMPS BEING ON THE COLDER SIDE OF WHAT HAS HISTORICALLY BEEN OBSERVED. DURING THIS PERIOD...ALL CYCLOGENESIS ASSOCIATED WITH SHORTWAVES IN THE NORTHWEST FLOW ALOFT SHOULD STAY WELL OFFSHORE...WITH THE ONLY SENSIBLE IMPACT WILL BE POSSIBLE OROGRAPHIC CIRRUS MONDAY NIGHT OR TUESDAY NIGHT. BY THE END OF THE PERIOD...MODELS INDICATE THE WEST COAST RIDGE MAY WEAKEN AND ALLOW ENERGY TO CROSS INTO THE CENTRAL US AND BRING A BETTER CHANCE OF PRECIP LATE NEXT WEEK INTO THE WEEKEND. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 1250 PM THURSDAY... 24 HOUR TAF PERIOD: LIGHT TO MODERATE RAIN WILL CONTINUE OVER THE WRN HALF OF THE AREA AND SLOWLY MOVE EAST THIS EVENING AS THE SURFACE LOW TRACKS NE INTO CENTRAL NC. HIGH CONFIDENCE THAT IFR AND LIFR AVIATION CONDITIONS WILL CONTINUE THROUGH APPROX 12Z FRIDAY. RAIN WILL CHANGE TO SNOW FROM WEST TO EAST...WITH SOME UNCERTAINTY ON THE EXACT TIMING OF THE CHANGE OVER. FOR NOW HAVE SNOW STARTING AROUND 23Z AT KINT AND KGSO TO 02-04Z AT KRDU AND KRWI...WITH THE CHANCE FOR A BRIEF PERIOD OF SNOW AT KFAY AROUND 05Z FRIDAY. SNOW AND FOG WILL KEEP LIFR CONDITIONS IN PLACE THROUGH 05Z-06Z. RESIDUAL LOW LEVEL MOISTURE MAY KEEP VISBYS LOW EVEN AFTER THE SNOW ENDS. AVIATION CONDITIONS SHOULD IMPROVE TO VFR AROUND SUNRISE. NNE WINDS AROUND 10-20 KTS THIS EVENING WILL SHIFT TO THE NW AS THE FRONT MOVES THROUGH CENTRAL NC OVERNIGHT. LOOKING AHEAD: VFR CONDITIONS EXPECTED FRIDAY NIGHT THROUGH TUESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY FOR NC028-042-043-077-078-083-084. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY FOR NCZ007>011-021>027-038>041-073>076. && $$ SYNOPSIS...HARTFIELD/KC NEAR TERM...HARTFIELD SHORT TERM...SMITH LONG TERM...SMITH AVIATION...WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
152 PM EST THU JAN 17 2013 .SYNOPSIS... STRENGTHENING LOW PRESSURE OVER NORTHEEAST GEORGIA THIS AFTERNOON WILL TRACK TO THE EAST NORTHEAST ACROSS SOUTHEAST NORTH CAROLINA THIS EVENING THROUGH MIDNIGHT... THEN OFF THE COAST LATE TONIGHT. COLD HIGH PRESSURE WILL BUILD IN FROM THE WEST FRIDAY INTO THE WEEKEND. && .NEAR TERM /THROUGH FRIDAY/... AS OF 150 PM THURSDAY... THROUGH TONIGHT: CONFIDENCE REMAINS HIGH IN THE OCCURRENCE OF SIGNIFICANT BANDED SNOWFALL OVER NRN AND WRN PORTIONS OF NC EARLY THIS EVENING THROUGH TONIGHT. INTENSIFYING SURFACE LOW PRESSURE... LOCATED OVER NE GA EARLY THIS AFTERNOON... WILL CONTINUE A STEADY ENE TRACK ALONG A FRONTAL ZONE ACROSS SE NC. THE NAM/GFS/RAP/SREF MEAN HAVE EXHIBITED EXCELLENT CONTINUITY THE LAST SEVERAL RUNS REGARDING TRACK AND TIMING... AND HAVE SHOWN A VERY SMALL SOUTHWARD TREND IN THE EXTENT OF COLDER AIR. DYNAMIC LIFT WITH THIS SYSTEM WILL BE EXTREMELY STRONG -- ESPECIALLY ALOFT WITH HIGH OMEGA FOCUSED IN THE CRUCIAL -12C TO -20C LAYER ALOFT -- BUT QUICK-HITTING. AN INTENSE UPPER DIVERGENCE MAX EXPECTED TO BE ROUGHLY OVER THE SRN NC FOOTHILLS AT 00Z WILL MOVE NE THROUGH CENTRAL NC BEFORE EXITING NE SECTIONS OF THE CWA BY AROUND 07Z. THIS IS IN TANDEM WITH THE PASSAGE OF STRONG Q-VECTOR CONVERGENCE... MID LEVEL DCVA AND A RISE/FALL COUPLET OF AROUND +/- 200 METERS... STRONG LOW LEVEL THETA-E ADVECTION... AND DEEP MOIST ISENTROPIC UPGLIDE. THE FACT THAT THIS SYSTEM IS STRENGTHENING QUICKLY UPON ARRIVAL IS ESPECIALLY TROUBLING IN THAT THE RESULTANT RAPID MASS FIELD ADJUSTMENTS ARE LIABLE TO SIGNIFICANT AND QUICKLY BOLSTER ASCENT AND HEIGHTEN THE EXTENT AND INTENSITY OF THE SNOW BANDING. MOISTURE AVAILABILITY WILL GENERALLY NOT BE A PROBLEM WITH VERY HIGH PW (OVER 200 PERCENT OF NORMAL) AND A STRONG MOISTURE TRANSPORT FROM THE GULF... ALTHOUGH THE INCOMING DRY SLOT ON THE SE SIDE OF THE LOW WILL BE WORTH MONITORING AND MAY LIMIT WINTRY TOTALS IN THE SOUTHEAST CWA (SEE BELOW). HOW FAST THE COLD AIR ARRIVES ESPECIALLY ALOFT REMAINS A CONCERN... ALTHOUGH THE MODELS INITIALIZED WELL AND ARE IN VERY GOOD AGREEMENT... BOOSTING CONFIDENCE IN THEIR TIMING OF THE ANTICIPATED THERMAL CHANGES. THE HEAVIEST SNOW BANDING IS LIKELY TO OCCUR OVER THE WRN AND NRN PIEDMONT... FROM HIGH ROCK AND BADIN LAKES... ACROSS THE I-40 AND HIGHWAY 64 CORRIDORS BETWEEN (AND INCLUDING) THE TRIAD AND THE TRIANGLE... UP TO KERR LAKE AND LAKE GASTON... VERY ROUGHLY FOLLOWING THE I-85 CORRIDOR TO THE NW... ALIGNED WITH THE AREA OF STRONGEST DEFORMATION ALOFT. KEY TIMING STILL LOOKS TO BE FROM 23Z UNTIL AROUND 07Z WITH A QUICK EXIT SOON THEREAFTER. SREF PROBABILITIES HAVE BEEN VERY CONSISTENT IN SHOWING A 70+ PERCENT CHANCE OF SNOWFALL RATES OVER ONE INCH PER HOUR ACROSS MUCH OF THE PIEDMONT AND FAR NRN COASTAL PLAIN FROM MID EVENING UNTIL THE EARLY OVERNIGHT HOURS. WITH THESE RATES AND THE TIMING OF A FEW HOURS OF HEAVY BANDED SNOW (STARTING AS A RAIN/SNOW MIX)... STORM TOTAL ACCUMULATIONS OF 2-4 INCHES IN THIS AREA WITH ISOLATED 5 INCH TOTALS LOOK QUITE REASONABLE. BORDERING THE WARNING AREA... STILL EXPECT AN INCH OR SO OF ACCUMULATION MAINLY ON GRASSY AREAS... WITH A LITTLE SLUSH ON ROADS POSSIBLE. SOUTH AND EAST OF HERE... INCLUDING FAYETTEVILLE AND CLINTON... A QUICK BURST OF MAINLY SNOW IS POSSIBLE WITH STRONG DYNAMIC COOLING THROUGH THE COLUMN AS THE LOW ALOFT PASSES BY... BUT THE WINDOW OF OPPORTUNITY WILL BE VERY SHORT AS AMOUNTS/DURATION WILL BE GREATLY LIMITED BY THE MID-UPPER LEVEL DRY SLOT ARRIVAL WITH NOTABLE DRYING ABOVE THE -5C LEVEL... SUPPRESSING CRYSTAL GROWTH ALOFT... PLUS BOUNDARY LAYER TEMPS SHOULD HOLD ABOVE FREEZING FOR MUCH OF THIS EVENT... NOT DROPPING TO NEAR FREEZING UNTIL PRECIP IS NEARLY GONE. EXPECT LIGHT ACCUMULATIONS OF A DUSTING CONFINED TO GRASSY AREAS. A SIDE NOTE: MID LEVEL LAPSE RATE PROGS ARE QUITE INTERESTING... INCLUDING THE 12 KM NAM WHICH INDICATES 850-500 MB VALUES OF 5.5-6.0 C/KM TRAVERSING THE CWA... JUST WNW OF THE 850 MB LOW TRACK... PRIMARILY BETWEEN 03Z AND 06Z. AND RECENT RAP RUNS TAKE THE 700-400 MB LAPSE RATES (WHICH CAPTURES THE MIXED PHASE REGION ALOFT) UP TO 7.0 C/KM OVER THE NW PIEDMONT TOWARD MIDNIGHT. CONSIDERING THIS POSSIBILITY FOR UPRIGHT INSTABILITY COMBINED WITH VIGOROUS DYNAMIC LIFT... A FEW LIGHTNING STRIKES WITHIN SNOW BANDS ARE CERTAINLY POSSIBLE... ALTHOUGH LIKELY TOO ISOLATED TO INCLUDE IN THE FORECAST AT THIS TIME. STRENGTHENING WINDS WILL BE AN ISSUE AS WELL WITH THE TIGHTENING MSLP GRADIENT AS THE LOW APPROACHES. WE ARE ALREADY SEEING FREQUENT GUSTS TO 25-40 KTS (ALTHOUGH SOME OF THIS MAY BE AUGMENTED BY A POSSIBLE GRAVITY WAVE). EXPECT A PERIOD OF SUSTAINED WINDS OF 15-25 MPH WITH SPORADIC GUSTS TO AROUND 30 MPH FROM LATE AFTERNOON UNTIL AROUND 1-2 AM. TEMPS SHOULD STEADILY DROP THROUGH THE REST OF THE AFTERNOON AND NIGHT. -GIH && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 245 AM THURSDAY... QUITE WEATHER IS EXPECTED TO FINALLY RETURN BY FRIDAY... WITH SUBSIDENCE AND DRYING IN THE WAKE OF THE THE QUICK MOVING STRONG S/W... WHICH WILL LIFT OFF TO THE NORTHEAST OF THE AREA ON FRIDAY. THIS WILL YIELD SUNNY SKIES FOR CENTRAL NC. HOWEVER... AFTERNOON LOW LEVEL THICKNESS VALUES ARE EXPECTED TO STRUGGLE TO REACH 1300 METERS. THIS COUPLED WITH POSSIBLY SOME SNOW ON THE GROUND ACROSS PORTIONS OF THE AREA WILL KEEP HIGH TEMPERATURES CHILLY. WILL GO HIGH TEMPS RANGING FROM THE LOW 40S ACROSS THE NORTH TO UPPER 40S ACROSS THE SOUTH. SURFACE HIGH PRESSURE WILL SETTLE OVER THE AREA FOR FRIDAY NIGHT... BEFORE SHIFTING OFFSHORE ON SATURDAY... WHILE MID/UPPER LEVEL FLOW GENERALLY REMAINS WESTERLY. THIS WILL CONTINUE TO YIELD SUNNY/CLEAR SKIES ACROSS THE AREA... WITH A COLD SATURDAY MORNING GIVEN THE CLEAR SKIES AND CALM TO LIGHT AND VARIABLE WINDS. THUS... WILL GO WITH LOWS IN THE LOW TO MID 20S FOR SATURDAY MORNING. HIGHS SATURDAY SHOULD BE WARMER THAN FRIDAY... AS A SOUTHERLY RETURN FLOW DEVELOPS AND AFTERNOON LOW LEVEL THICKNESS VALUES REBOUND INTO THE 1320S. HOWEVER... STILL THINK WE WILL SEE HIGH TEMPS ONLY REBOUND TO NEAR NORMAL OR SLIGHTLY BELOW NORMAL... GENERALLY IN THE UPPER 40S TO LOWER 50S... AS THE MIXED LAYER WILL BE QUITE SHALLOW. TEMPS SUNDAY MORNING WILL FOLLOW THE SAME TREND (WARMER THAN THE PREVIOUS MORNING)... WITH LOWS EXPECTED TO GENERALLY RANGE FROM 30-35 DEGREES. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 3 AM THURSDAY... MID/UPPER FLOW IS EXPECTED TO BECOME MORE AMPLIFIED WITH A DEEP TROUGH DEVELOPING ACROSS THE EASTERN U.S.... ALLOWING MUCH COLDER AIR TO SURGE INTO THE AREA EARLY NEXT WEEK. A COUPLE OF DRY COLD FRONT ARE EXPECTED TO MOVE THROUGH THE AREA DURING THIS TIMEFRAME... ONE LATE SUNDAY INTO SUNDAY AND ANOTHER POSSIBLE DRY COLD FRONT ON WEDNESDAY. SUNDAY LOOKS TO BE THE WARMEST DAY OF THE MEDIUM RANGE RANGE... AHEAD OF A STRONG COLD FRONT WHICH SHOULD BRING SOME OF THE COLD AIR YET OF THE WINTER SEASON. THUS... EXPECT HIGHS SUNDAY WILL RANGE FROM AROUND 50 NW TO NEAR 60 SOUTH/SOUTHEAST (A BIT OF TRICKY TEMP FORECAST THOUGH GIVEN ABOUT 6 TO 9 HOURS DIFFERENCE BETWEEN THE GFS AND ECWMF). HIGHS AND LOW TEMPS FOR THE REMAINDER OF THE PERIOD ARE EXPECTED TO BE BELOW NORMAL... WITH LOW TEMPS GENERALLY IN THE 20S... WITH POSSIBLY EVEN SOME TEENS BY TUESDAY MORNING IN THE COLD OUTLYING AREAS. HIGH TEMPS ARE GENERALLY EXPECTED TO BE IN THE 40S... WITH MAYBE A FEW LOCATIONS ACROSS THE NORTH ON TUESDAY STRUGGLING TO REACH 40 DEGREES. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 1250 PM THURSDAY... 24 HOUR TAF PERIOD: LIGHT TO MODERATE RAIN WILL CONTINUE OVER THE WRN HALF OF THE AREA AND SLOWLY MOVE EAST THIS EVENING AS THE SURFACE LOW TRACKS NE INTO CENTRAL NC. HIGH CONFIDENCE THAT IFR AND LIFR AVIATION CONDITIONS WILL CONTINUE THROUGH APPROX 12Z FRIDAY. RAIN WILL CHANGE TO SNOW FROM WEST TO EAST...WITH SOME UNCERTAINTY ON THE EXACT TIMING OF THE CHANGE OVER. FOR NOW HAVE SNOW STARTING AROUND 23Z AT KINT AND KGSO TO 02-04Z AT KRDU AND KRWI...WITH THE CHANCE FOR A BRIEF PERIOD OF SNOW AT KFAY AROUND 05Z FRIDAY. SNOW AND FOG WILL KEEP LIFR CONDITIONS IN PLACE THROUGH 05Z-06Z. RESIDUAL LOW LEVEL MOISTURE MAY KEEP VISBYS LOW EVEN AFTER THE SNOW ENDS. AVIATION CONDITIONS SHOULD IMPROVE TO VFR AROUND SUNRISE. NNE WINDS AROUND 10-20 KTS THIS EVENING WILL SHIFT TO THE NW AS THE FRONT MOVES THROUGH CENTRAL NC OVERNIGHT. LOOKING AHEAD: VFR CONDITIONS EXPECTED FRIDAY NIGHT THROUGH TUESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY FOR NC028-042-043-077-078-083-084. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY FOR NCZ007>011-021>027-038>041-073>076. && $$ SYNOPSIS...HARTFIELD/KC NEAR TERM...HARTFIELD SHORT TERM...BSD LONG TERM...BSD AVIATION...WSS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
959 AM CST THU JAN 17 2013 .DISCUSSION... THE MAIN CHALLENGE TODAY WILL BE TEMPS. SFC HIGH PRESSURE WILL BUILD INTO THE REGION...AND TEMPS WON/T WARM TOO MUCH FROM CURRENT READINGS. WILL TAKE A LOOK AT CURRENT TEMPS...BUT NOT EXPECTING TOO MANY CHANGES FROM CURRENT FORECAST THIS MORNING. && .AVIATION... MIXED VFR AND MVFR CLOUD DECKS AROUND THIS MORNING WITH SOME POTENTIAL FOR CLEARING INTO NE ND/NW MN THRU THIS AFTN. WINDS WILL BE PRETTY LIGHT TODAY...GENERALLY 10 KTS OR LESS...BUT MAY BE MORE VARIABLE IN DIRECTION DUE TO RATHER WEAK SFC FEATURES. WINDS WILL TURN SOUTHERLY TONIGHT AND INCREASE TO THE 10 TO 20 KT RANGE IN THE RRV AND ERN ND. CLOUDS WILL SPREAD OVER THE REGION AGAIN WITH LIGHT SNOW MOVING INTO DVL-GFK BY 06Z AND THEN SPREADING EAST. SOME MVFR CIGS AND VSBYS PSBL WITH THIS SYSTEM. && .PREV DISCUSSION... /ISSUED 615 AM CST THU JAN 17 2013/ UPDATE... FLURRIES PERSISTING LONGER THAN THOUGHT PER RADAR AND OBS. ONCE AGAIN RAP MODEL DOING WELL AND HAS THE FLURRIES EXITING THE SOUTHEAST FCST AREA 16-17Z. WILL MENTION FLURRIES IN MUCH OF NW/WCNTRL MN INTO FAR SE ND UNTIL THEN AS WAVE MOVES THROUGH. NOTING A PERIOD OF 20 TO 30 KT WIND GUST SPREADING THRU DVL BASIN WITH CLEARING PROGRESSING SOUTHEAST QUICKLY. PREV DISCUSSION... /ISSUED 344 AM CST THU JAN 17 2013/ SHORT TERM... WATER VAPOR SHOWS THE RIGHT FRONT OF A 300 MB 150KT JET OVER NE ND/NW MN THIS MORNING. A COUPLE OF WEAK 500 MB SHORT WAVES ON THE SOUTH EDGE OF JET MAX FROM SRN SASK INTO CNTRL-SE ND. ONCE WEAK SYSTEM MOVING THRU ERN ND ATTM INTO WCNTRL MN PRODUCING SOME FLURRIES. MAIN RESULT OF JET MAX IS TO PRODUCE AN EXPANSIVE CLOUD SHIELD WHICH HAS MOVED OVER ALL OF THE FCST AREA OVERNIGHT CAUSING RISING TEMPS IN NW MN WHICH DID DROP INTO THE MID TEENS BELOW EARLY THIS EVE. AS A RESULT OF WARMING TEMPS AND LIGHT WINDS HAVE CANCELLED WIND CHILL ADV. SHORT TERM MODELS SUCH AS THE RAP INSIST SOME CLEARING WILL MOVE INTO FAR NE ND AND NW MN LATER THIS MORNING AND AFTN AND SOME CLEARING IS NOTED IN PATCHY FASHION MOVING INTO SW MANITOBA ATTM FROM CNTRL SASK. THUS SOME SUN PSBL LATER TODAY. TEMPS A REAL CONCERN THRU THE PD. SFC MAP SHOWS A WK LOW NR DVL MOVING SOUTHEAST ALONG A THERMAL BOUNDARY FROM SE SASK INTO SE ND...NR AN ESTEVAN TO MINOT TO JAMESTOWN TO ABERDEEN LINE. TEMPS INTO THE TEENS IN THE FAR WRN FCST AREA ATTM AND EXPECT AS WINDS TURN A BIT MORE NORTH AFTER SUNRISE TEMPS TO FALL A BIT. REST OF THE FCST AREA TO REMAIN CHILLY WITH HIGHS TODAY IN THE SINGLE DIGITS...WITH TEMPS STRUGGLING TO REACH ZERO IN FAR NORTHEAST FCST AREA WHERE COLDEST AIRMASS RESIDES. TONIGHT WILL SEE NEXT SHORT WAVE WHICH WILL MOVE INTO CNTRL ALBERTA MOVE SOUTHEAST. THIS SYSTEM WILL BE MORE PRESENT AT THE 925-850 MB LEVEL WHERE LOWER LEVEL WARM ADVECTION ZONE WILL STRENGTHEN TONIGHT FROM WRN MANITOBA INTO ERN ND/NW MN. THUS DO LOOK FOR A BAND OF WARM ADV SNOW TO EXPAND SOUTHEAST INTO DVL BASIN BEFORE 06Z AND THEN SPREAD EAST OVERNIGHT...WITH WARM ADV MAXIMIZING IN NW MN LATE TONIGHT WHERE 1-2 INCHES OF SNOW MAY FALL UP IN THE ROSEAU-WARROAD-BAUDETTE AREAS. STRONG WARMING AT THE SFC TO AS WINDS TURN SOUTHERLY AND INCREASE TO 10 TO 20 KTS. AS WHAT OCCURRED A FEW DAYS AGO EXPECT RISING TEMPS OVER ERN ND TONIGHT REACHING THE 20S. AIRMASS TO REMAIN RATHER MILD INTO FRIDAY AS WELL SOUTH OF A STRONGER SHORT WAVE AND SFC LOW WHICH WILL MOVE FROM NORTHERN ALBERTA SOUTHEAST TOWARD LAKE OF THE WOODS REGION SATURDAY. SOME LIGHT SNOW WITH THIS SYSTEM AS WELL...BUT MOSTLY OVER FAR NW MN INTO ONTARIO. TEMPS FRIDAY SOUTH OF THE LOW WILL RISE INTO THE LOW-MID 30S AS 925 MB TEMPS RISE TO ABOVE ZERO IN AREAS FROM DVL TO FARGO TO FERGUS FALLS SOUTHWARD. SATURDAY PROMISES TO BE AN INTERESTING DAY AS SFC LOW MOVES FROM LAKE OF THE WOODS REGION SOUTHEAST AND IN ITS WAKE WILL BE STRONG COLD ADVECTION WITH 925 MB TEMPS DROPPING SOME 20 DEGREES DURING THE DAY SATURDAY WITH 25 TO 30 KT SFC WINDS FROM THE NORTH. HOURLY TEMPS A REAL HEADACHE AS COULD WELL BE IN THE 20S TO START IN SE ND/WCNTRL MN...BUT ALL AREAS WILL SEE FALLING TEMPS INTO THE SINGLE DIGITS ABOVE AND BELOW ZERO IN THE AFTN WITH WIND CHILLS IN THE TEENS AND 20S BELOW. HIGH PRESSURE WILL MOVE IN SAT NIGHT WITH LIGHTER WINDS AND MAYBE A PERIOD OF RATHER CLEAR SKY ESP IN THE EVENING. THIS SHOULD ALLOW FOR WIDESPREAD TEENS BLO ZERO...BUT CLOUDS IN ADVANCE OF THE NEXT SYSTEM DUE TO ARRIVE SUNDAY WILL LIKELY PREVENT ANY HUGE TEMP DROP. LONG TERM (SUNDAY-WEDNESDAY)... THE 00Z GFS/ECMWF/GEM ARE ALL IN GOOD AGREEMENT THROUGH MUCH OF THE PERIOD WITH THE OVERALL SYNOPTIC PATTERN EVOLUTION. STRONGLY MERIDIONAL NORTHWESTERLY FLOW ALOFT IN RESPONSE TO HIGH AMPLITUDE RIDGING ACROSS WESTERN NORTH AMERICA WILL DRIVE ARCTIC AIR SOUTH ACROSS THE NORTHERN PLAINS. BOTH THE GFS/ECMWF SHOW 925 MB TEMPS FALLING INTO THE -25C TO -30C RANGE BY 12Z MONDAY...BEFORE SLOW MODIFICATION OF THE AIR MASS TAKES PLACE BY THE END OF THE PERIOD AS THE UPPER AIR PATTERN BEGINS TO DE-AMPLIFY AND THICKNESSES RISE. HIGH TEMPS WILL GENERALLY BE BELOW ZERO IN MOST AREAS SUNDAY AND MONDAY...RECOVERING INTO THE SINGLE DIGITS AND TEENS BY WEDNESDAY. LOW TEMPS LIKELY WILL DEPEND ON CLOUDS AND SFC HIGH POSITION TO SOME DEGREE...BUT TEMPS DOWN TO NEAR OR BELOW -20F EXPECTED IN MANY AREAS ON SUNDAY NIGHT AND AGAIN IN SOME AREAS ON MONDAY NIGHT. AS HAS BEEN THE CASE RECENTLY WITHIN THE NORTHWEST FLOW ALOFT...WEAK EMBEDDED WAVES MAY BRING PERIODIC CHANCES FOR LIGHT SNOW AND FLURRIES...BUT THE TIMING AND LOCATION OF THESE SYSTEMS IS UNCERTAIN AT THIS RANGE. MAINTAINED LOW POPS FOR SUNDAY WITH ONE SYSTEM DROPPING OUT OF CANADA. SOME INDICATION OF ANOTHER WEAK SYSTEM FOR MONDAY NIGHT OR TUESDAY...BUT WILL STICK WITH DRY FORECAST FOR NOW DUE TO LOW CONFIDENCE. OTHERWISE...A SERIES OF ARCTIC HIGHS DROPPING SOUTH WILL RESULT IN FAIRLY TRANQUIL WEATHER FOR MUCH OF THE PERIOD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ DK
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
615 AM CST THU JAN 17 2013 .UPDATE... FLURRIES PERSISTING LONGER THAN THOUGHT PER RADAR AND OBS. ONCE AGAIN RAP MODEL DOING WELL AND HAS THE FLURRIES EXITING THE SOUTHEAST FCST AREA 16-17Z. WILL MENTION FLURRIES IN MUCH OF NW/WCNTRL MN INTO FAR SE ND UNTIL THEN AS WAVE MOVES THROUGH. NOTING A PERIOD OF 20 TO 30 KT WIND GUST SPREADING THRU DVL BASIN WITH CLEARING PROGRESSING SOUTHEAST QUICKLY. && .PREV DISCUSSION... /ISSUED 344 AM CST THU JAN 17 2013/ SHORT TERM... WATER VAPOR SHOWS THE RIGHT FRONT OF A 300 MB 150KT JET OVER NE ND/NW MN THIS MORNING. A COUPLE OF WEAK 500 MB SHORT WAVES ON THE SOUTH EDGE OF JET MAX FROM SRN SASK INTO CNTRL-SE ND. ONCE WEAK SYSTEM MOVING THRU ERN ND ATTM INTO WCNTRL MN PRODUCING SOME FLURRIES. MAIN RESULT OF JET MAX IS TO PRODUCE AN EXPANSIVE CLOUD SHIELD WHICH HAS MOVED OVER ALL OF THE FCST AREA OVERNIGHT CAUSING RISING TEMPS IN NW MN WHICH DID DROP INTO THE MID TEENS BELOW EARLY THIS EVE. AS A RESULT OF WARMING TEMPS AND LIGHT WINDS HAVE CANCELLED WIND CHILL ADV. SHORT TERM MODELS SUCH AS THE RAP INSIST SOME CLEARING WILL MOVE INTO FAR NE ND AND NW MN LATER THIS MORNING AND AFTN AND SOME CLEARING IS NOTED IN PATCHY FASION MOVING INTO SW MANITOBA ATTM FROM CNTRL SASK. THUS SOME SUN PSBL LATER TODAY. TEMPS A REAL CONCERN THRU THE PD. SFC MAP SHOWS A WK LOW NR DVL MOVING SOUTHEAST ALONG A THERMAL BOUNDARY FROM SE SASK INTO SE ND...NR AN ESTEVAN TO MINOT TO JAMESTOWN TO ABERDEEN LINE. TEMPS INTO THE TEENS IN THE FAR WRN FCST AREA ATTM AND EXPECT AS WINDS TURN A BIT MORE NORTH AFTER SUNRISE TEMPS TO FALL A BIT. REST OF THE FCST AREA TO REMAIN CHILLY WITH HIGHS TODAY IN THE SINGLE DIGITS...WITH TEMPS STRUGGLING TO REACH ZERO IN FAR NORTHEAST FCST AREA WHERE COLDEST AIRMASS RESIDES. TONIGHT WILL SEE NEXT SHORT WAVE WHICH WILL MOVE INTO CNTRL ALBERTA MOVE SOUTHEAST. THIS SYSTEM WILL BE MORE PRESENT AT THE 925-850 MB LEVEL WHERE LOWER LEVEL WARM ADVECTION ZONE WILL STRENGTHEN TONIGHT FROM WRN MANITOBA INTO ERN ND/NW MN. THUS DO LOOK FOR A BAND OF WARM ADV SNOW TO EXPAND SOUTHEAST INTO DVL BASIN BEFORE 06Z AND THEN SPREAD EAST OVERNIGHT...WITH WARM ADV MAXIMIZING IN NW MN LATE TONIGHT WHERE 1-2 INCHES OF SNOW MAY FALL UP IN THE ROSEAU-WARROAD-BAUDETTE AREAS. STRONG WARMING AT THE SFC TO AS WINDS TURN SOUTHERLY AND INCREASE TO 10 TO 20 KTS. AS WHAT OCCURRED A FEW DAYS AGO EXPECT RISING TEMPS OVER ERN ND TONIGHT REACHING THE 20S. AIRMASS TO REMAIN RATHER MILD INTO FRIDAY AS WELL SOUTH OF A STRONGER SHORT WAVE AND SFC LOW WHICH WILL MOVE FROM NORTHERN ALBERTA SOUTHEAST TOWARD LAKE OF THE WOODS REGION SATURDAY. SOME LIGHT SNOW WITH THIS SYSTEM AS WELL...BUT MOSTLY OVER FAR NW MN INTO ONTARIO. TEMPS FRIDAY SOUTH OF THE LOW WILL RISE INTO THE LOW-MID 30S AS 925 MB TEMPS RISE TO ABOVE ZERO IN AREAS FROM DVL TO FARGO TO FERGUS FALLS SOUTHWARD. SATURDAY PROMISES TO BE AN INTERESTING DAY AS SFC LOW MOVES FROM LAKE OF THE WOODS REGION SOUTHEAST AND IN ITS WAKE WILL BE STRONG COLD ADVECTION WITH 925 MB TEMPS DROPPING SOME 20 DEGREES DURING THE DAY SATURDAY WITH 25 TO 30 KT SFC WINDS FROM THE NORTH. HOURLY TEMPS A REAL HEADACHE AS COULD WELL BE IN THE 20S TO START IN SE ND/WCNTRL MN...BUT ALL AREAS WILL SEE FALLING TEMPS INTO THE SINGLE DIGITS ABOVE AND BELOW ZERO IN THE AFTN WITH WIND CHILLS IN THE TEENS AND 20S BELOW. HIGH PRESSURE WILL MOVE IN SAT NIGHT WITH LIGHTER WINDS AND MAYBE A PERIOD OF RATHER CLEAR SKY ESP IN THE EVENING. THIS SHOULD ALLOW FOR WIDESPREAD TEENS BLO ZERO...BUT CLOUDS IN ADVANCE OF THE NEXT SYSTEM DUE TO ARRIVE SUNDAY WILL LIKELY PREVENT ANY HUGE TEMP DROP. LONG TERM (SUNDAY-WEDNESDAY)... THE 00Z GFS/ECMWF/GEM ARE ALL IN GOOD AGREEMENT THROUGH MUCH OF THE PERIOD WITH THE OVERALL SYNOPTIC PATTERN EVOLUTION. STRONGLY MERIDIONAL NORTHWESTERLY FLOW ALOFT IN RESPONSE TO HIGH AMPLITUDE RIDGING ACROSS WESTERN NORTH AMERICA WILL DRIVE ARCTIC AIR SOUTH ACROSS THE NORTHERN PLAINS. BOTH THE GFS/ECMWF SHOW 925 MB TEMPS FALLING INTO THE -25C TO -30C RANGE BY 12Z MONDAY...BEFORE SLOW MODIFICATION OF THE AIR MASS TAKES PLACE BY THE END OF THE PERIOD AS THE UPPER AIR PATTERN BEGINS TO DE-AMPLIFY AND THICKNESSES RISE. HIGH TEMPS WILL GENERALLY BE BELOW ZERO IN MOST AREAS SUNDAY AND MONDAY...RECOVERING INTO THE SINGLE DIGITS AND TEENS BY WEDNESDAY. LOW TEMPS LIKELY WILL DEPEND ON CLOUDS AND SFC HIGH POSITION TO SOME DEGREE...BUT TEMPS DOWN TO NEAR OR BELOW -20F EXPECTED IN MANY AREAS ON SUNDAY NIGHT AND AGAIN IN SOME AREAS ON MONDAY NIGHT. AS HAS BEEN THE CASE RECENTLY WITHIN THE NORTHWEST FLOW ALOFT...WEAK EMBEDDED WAVES MAY BRING PERIODIC CHANCES FOR LIGHT SNOW AND FLURRIES...BUT THE TIMING AND LOCATION OF THESE SYSTEMS IS UNCERTAIN AT THIS RANGE. MAINTAINED LOW POPS FOR SUNDAY WITH ONE SYSTEM DROPPING OUT OF CANADA. SOME INDICATION OF ANOTHER WEAK SYSTEM FOR MONDAY NIGHT OR TUESDAY...BUT WILL STICK WITH DRY FORECAST FOR NOW DUE TO LOW CONFIDENCE. OTHERWISE...A SERIES OF ARCTIC HIGHS DROPPING SOUTH WILL RESULT IN FAIRLY TRANQUIL WEATHER FOR MUCH OF THE PERIOD. AVIATION... MIXED VFR AND MVFR CLOUD DECKS AROUND THIS MORNING WITH SOME POTENTIAL FOR CLEARING INTO NE ND/NW MN LATER THIS MORNING THRU THIS AFTN. WINDS WILL BE PRETTY LIGHT TODAY...GENERALLY 10 KTS OR LESS...BUT MAY BE MORE VARIABLE IN DIRECTION DUE TO RATHER WEAK SFC FEATURES. WINDS WILL TURN SOUTHERY TONIGHT AND INCREASE TO THE 10 TO 20 KT RANGE IN THE RRV AND ERN ND. CLOUDS WILL SPREAD OVER THE REGION AGAIN WITH LIGHT SNOW MOVING INTO DVL-GFK BY 06Z AND THEN SPREADING EAST. SOME MVFR CIGS AND VSBYS PSBL WITH THIS SYSTEM. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE/MAKOWSKI
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
344 AM CST THU JAN 17 2013 .SHORT TERM... WATER VAPOR SHOWS THE RIGHT FRONT OF A 300 MB 150KT JET OVER NE ND/NW MN THIS MORNING. A COUPLE OF WEAK 500 MB SHORT WAVES ON THE SOUTH EDGE OF JET MAX FROM SRN SASK INTO CNTRL-SE ND. ONCE WEAK SYSTEM MOVING THRU ERN ND ATTM INTO WCNTRL MN PRODUCING SOME FLURRIES. MAIN RESULT OF JET MAX IS TO PRODUCE AN EXPANSIVE CLOUD SHIELD WHICH HAS MOVED OVER ALL OF THE FCST AREA OVERNIGHT CAUSING RISING TEMPS IN NW MN WHICH DID DROP INTO THE MID TEENS BELOW EARLY THIS EVE. AS A RESULT OF WARMING TEMPS AND LIGHT WINDS HAVE CANCELLED WIND CHILL ADV. SHORT TERM MODELS SUCH AS THE RAP INSIST SOME CLEARING WILL MOVE INTO FAR NE ND AND NW MN LATER THIS MORNING AND AFTN AND SOME CLEARING IS NOTED IN PATCHY FASION MOVING INTO SW MANITOBA ATTM FROM CNTRL SASK. THUS SOME SUN PSBL LATER TODAY. TEMPS A REAL CONCERN THRU THE PD. SFC MAP SHOWS A WK LOW NR DVL MOVING SOUTHEAST ALONG A THERMAL BOUNDARY FROM SE SASK INTO SE ND...NR AN ESTEVAN TO MINOT TO JAMESTOWN TO ABERDEEN LINE. TEMPS INTO THE TEENS IN THE FAR WRN FCST AREA ATTM AND EXPECT AS WINDS TURN A BIT MORE NORTH AFTER SUNRISE TEMPS TO FALL A BIT. REST OF THE FCST AREA TO REMAIN CHILLY WITH HIGHS TODAY IN THE SINGLE DIGITS...WITH TEMPS STRUGGLING TO REACH ZERO IN FAR NORTHEAST FCST AREA WHERE COLDEST AIRMASS RESIDES. TONIGHT WILL SEE NEXT SHORT WAVE WHICH WILL MOVE INTO CNTRL ALBERTA MOVE SOUTHEAST. THIS SYSTEM WILL BE MORE PRESENT AT THE 925-850 MB LEVEL WHERE LOWER LEVEL WARM ADVECTION ZONE WILL STRENGTHEN TONIGHT FROM WRN MANITOBA INTO ERN ND/NW MN. THUS DO LOOK FOR A BAND OF WARM ADV SNOW TO EXPAND SOUTHEAST INTO DVL BASIN BEFORE 06Z AND THEN SPREAD EAST OVERNIGHT...WITH WARM ADV MAXIMIZING IN NW MN LATE TONIGHT WHERE 1-2 INCHES OF SNOW MAY FALL UP IN THE ROSEAU-WARROAD-BAUDETTE AREAS. STRONG WARMING AT THE SFC TO AS WINDS TURN SOUTHERLY AND INCREASE TO 10 TO 20 KTS. AS WHAT OCCURRED A FEW DAYS AGO EXPECT RISING TEMPS OVER ERN ND TONIGHT REACHING THE 20S. AIRMASS TO REMAIN RATHER MILD INTO FRIDAY AS WELL SOUTH OF A STRONGER SHORT WAVE AND SFC LOW WHICH WILL MOVE FROM NORTHERN ALBERTA SOUTHEAST TOWARD LAKE OF THE WOODS REGION SATURDAY. SOME LIGHT SNOW WITH THIS SYSTEM AS WELL...BUT MOSTLY OVER FAR NW MN INTO ONTARIO. TEMPS FRIDAY SOUTH OF THE LOW WILL RISE INTO THE LOW-MID 30S AS 925 MB TEMPS RISE TO ABOVE ZERO IN AREAS FROM DVL TO FARGO TO FERGUS FALLS SOUTHWARD. SATURDAY PROMISES TO BE AN INTERESTING DAY AS SFC LOW MOVES FROM LAKE OF THE WOODS REGION SOUTHEAST AND IN ITS WAKE WILL BE STRONG COLD ADVECTION WITH 925 MB TEMPS DROPPING SOME 20 DEGREES DURING THE DAY SATURDAY WITH 25 TO 30 KT SFC WINDS FROM THE NORTH. HOURLY TEMPS A REAL HEADACHE AS COULD WELL BE IN THE 20S TO START IN SE ND/WCNTRL MN...BUT ALL AREAS WILL SEE FALLING TEMPS INTO THE SINGLE DIGITS ABOVE AND BELOW ZERO IN THE AFTN WITH WIND CHILLS IN THE TEENS AND 20S BELOW. HIGH PRESSURE WILL MOVE IN SAT NIGHT WITH LIGHTER WINDS AND MAYBE A PERIOD OF RATHER CLEAR SKY ESP IN THE EVENING. THIS SHOULD ALLOW FOR WIDESPREAD TEENS BLO ZERO...BUT CLOUDS IN ADVANCE OF THE NEXT SYSTEM DUE TO ARRIVE SUNDAY WILL LIKELY PREVENT ANY HUGE TEMP DROP. .LONG TERM (SUNDAY-WEDNESDAY)... THE 00Z GFS/ECMWF/GEM ARE ALL IN GOOD AGREEMENT THROUGH MUCH OF THE PERIOD WITH THE OVERALL SYNOPTIC PATTERN EVOLUTION. STRONGLY MERIDIONAL NORTHWESTERLY FLOW ALOFT IN RESPONSE TO HIGH AMPLITUDE RIDGING ACROSS WESTERN NORTH AMERICA WILL DRIVE ARCTIC AIR SOUTH ACROSS THE NORTHERN PLAINS. BOTH THE GFS/ECMWF SHOW 925 MB TEMPS FALLING INTO THE -25C TO -30C RANGE BY 12Z MONDAY...BEFORE SLOW MODIFICATION OF THE AIR MASS TAKES PLACE BY THE END OF THE PERIOD AS THE UPPER AIR PATTERN BEGINS TO DE-AMPLIFY AND THICKNESSES RISE. HIGH TEMPS WILL GENERALLY BE BELOW ZERO IN MOST AREAS SUNDAY AND MONDAY...RECOVERING INTO THE SINGLE DIGITS AND TEENS BY WEDNESDAY. LOW TEMPS LIKELY WILL DEPEND ON CLOUDS AND SFC HIGH POSITION TO SOME DEGREE...BUT TEMPS DOWN TO NEAR OR BELOW -20F EXPECTED IN MANY AREAS ON SUNDAY NIGHT AND AGAIN IN SOME AREAS ON MONDAY NIGHT. AS HAS BEEN THE CASE RECENTLY WITHIN THE NORTHWEST FLOW ALOFT...WEAK EMBEDDED WAVES MAY BRING PERIODIC CHANCES FOR LIGHT SNOW AND FLURRIES...BUT THE TIMING AND LOCATION OF THESE SYSTEMS IS UNCERTAIN AT THIS RANGE. MAINTAINED LOW POPS FOR SUNDAY WITH ONE SYSTEM DROPPING OUT OF CANADA. SOME INDICATION OF ANOTHER WEAK SYSTEM FOR MONDAY NIGHT OR TUESDAY...BUT WILL STICK WITH DRY FORECAST FOR NOW DUE TO LOW CONFIDENCE. OTHERWISE...A SERIES OF ARCTIC HIGHS DROPPING SOUTH WILL RESULT IN FAIRLY TRANQUIL WEATHER FOR MUCH OF THE PERIOD. && .AVIATION... MIXED VFR AND MVFR CLOUD DECKS AROUND THIS MORNING WITH SOME POTENTIAL FOR CLEARING INTO NE ND/NW MN LATER THIS MORNING THRU THIS AFTN. WINDS WILL BE PRETTY LIGHT TODAY...GENERALLY 10 KTS OR LESS...BUT MAY BE MORE VARIABLE IN DIRECTION DUE TO RATHER WEAK SFC FEATURES. WINDS WILL TURN SOUTHERY TONIGHT AND INCREASE TO THE 10 TO 20 KT RANGE IN THE RRV AND ERN ND. CLOUDS WILL SPREAD OVER THE REGION AGAIN WITH LIGHT SNOW MOVING INTO DVL-GFK BY 06Z AND THEN SPREADING EAST. SOME MVFR CIGS AND VSBYS PSBL WITH THIS SYSTEM. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE/MAKOWSKI
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1129 PM CST WED JAN 16 2013 .DISCUSSION...LATEST SURFACE MAP SHOWS A STATIONARY FRONT STRETCHING FROM MOOSE JAW IN CANADA...SOUTHEAST TO WILLISTON...DICKINSON AND CURVING INTO PIERRE SOUTH DAKOTA. 925MB ISOTHERM STRUCTURE ON THE NAM AND HOURLY RAP MODEL CLEARLY SHOW THE BAROCLINIC BOUNDARY DEFINING THIS FRONT. TWO WAVES OF LOW PRESSURE WERE OBSERVED...ONE NEAR KILLDEER IN DUNN COUNTY...AND THE SECOND FURTHER UPSTREAM WEST OF CROSBY. MODEL GUIDANCE SUGGESTS RISING TEMPERATURES OVERNIGHT FOR MANY LOCATIONS ALONG THE FRONT AND AHEAD OF THE LOWS. THIS WOULD MAINLY AFFECT SOUTH CENTRAL NORTH DAKOTA. AS EACH WAVE SLIDES ALONG THE BOUNDARY OVERNIGHT INTO THURSDAY MORNING...THE BOUNDARY IS FORCED TO BULGE NORTHEAST...THUS ALLOWING A WARM-UP FROM THE SFC-925MB...THEN QUICKLY COOLS DOWN AGAIN AS THE LOW DEPARTS AND THE BAROCLINIC ZONE IS FORCED TO RETREAT FURTHER SOUTHWEST. TEMPERATURES WILL BE A CHALLENGE OVERNIGHT...VERY MUCH DEPENDENT ON THE POSITION OF THE SURFACE LOWS AT EACH HOUR THROUGH 15Z THURSDAY. THIS TREND IS ALREADY OCCURRING...AS KBIS HAS WARMED 4 DEGREES IN THE LAST 3HRS. THE CHALLENGE WILL BE JUST HOW MUCH WARMING WILL OCCUR. THE RAP SUGGESTS TEMPERATURES RISING TO AROUND 32F BY 12Z AT KBIS. WILL BLEND THE CURRENT FORECAST WITH THE RAP WHICH WILL SHOW A WARMING TREND TO AROUND 30 BY MORNING. ONCE THE SURFACE LOW SHIFTS TO THE SOUTHEAST...TEMPERATURES WILL ACTUALLY FALL DURING THE 12Z TO 18Z TIME FRAME. WILL ALSO CONTINUE WITH THE MENTION OF FLURRIES OVERNIGHT WHERE THE BAROCLINIC ZONE AND SURFACE LOWS INTERACT. CURRENT RADAR RETURNS REMAIN CONSISTENT WITH THIS IDEA. && .AVIATION...A FRONTAL BOUNDARY WILL REMAIN SITUATED NORTHWEST TO SOUTHEAST ACROSS THE FORECAST AREA TONIGHT. LOW PRESSURE SLIDING SOUTHEAST ALONG THE BOUNDARY WILL PRODUCE AREAS OF MVFR CLOUDS AND POSSIBLY A FEW PERIODS OF LIGHT SNOW...MAINLY FROM WILLISTON AND MINOT SOUTHEAST TO BISMARCK AND JAMESTOWN. THE BOUNDARY WILL DROP SOUTH ON THURSDAY WITH SURFACE FLOW TURNING MORE NORTHERLY EAST OF THE BOUNDARY...AND A WESTERLY FLOW WEST OF THE BOUNDARY. THE BOUNDARY WILL THEN LIFT NORTHEAST LATE THURSDAY AND THURSDAY NIGHT AS A WARM FRONT. DEPICTING LOW CEILINGS WILL BE TROUBLESOME UNTIL LATE IN THE FORECAST PERIOD WHEN THE BOUNDARY LIFTS NORTHEAST AND DRIER AIR WORKS INTO THE AREA BEHIND THE WARM FRONT. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...KS AVIATION...TWH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1250 PM EST THU JAN 17 2013 .SYNOPSIS... CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLEY RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH CLOUD CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF LOW CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED WITH MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON HOW TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY. THE HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT IN HIGH TEMPERATURES IN THE 30S. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY NIGHT AND FRIDAY. BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE UPPER 20S FOR THE MOST PART. SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE 40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH. A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER AIR ACROSS THE REGION SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS. ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO REACH 20 IN MOST LOCATIONS. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT AND WILL MOVE OFF TO THE SOUTHEAST ON FRIDAY. A WARM FRONT IS FORECAST TO PIVOT NORTHEAST ACROSS THE GREAT LAKES ON FRIDAY. MODELS CONTINUE TO OFFER VARYING SOLUTIONS ON THE AMOUNT OF LOW LEVEL MOISTURE PRESENT ACROSS THE REGION AHEAD OF A WEAKENING COLD FRONT. VISIBLE SATELLITE IMAGERY HAS BEEN SHOWING LOW LEVEL CUMULUS DEVELOPING ACROSS NW OHIO INTO CENTRAL INDIANA. ATTM...EXPECT A PERIOD OF MVFR CIGS AT KDAY AND HAVE ONLY PLACED SCATTERED CUMULUS ELSEWHERE. WILL CONTINUE TO MONITOR. OTHERWISE...AM EXPECTING DIURNAL CUMULUS CLOUDS TO DISSIPATE AFTER SUNSET. FOR THE OVERNIGHT PERIOD...MODELS AGAIN KEEP HINTING AT SOME LOW LEVEL MOISTURE ADVECTING CLOSE TO THE NORTHERN TAF SITES OF KDAY AND KCMH. I DO NOT HAVE CONFIDENCE ATTM TO PLACE IN THE TAF SO HAVE LEFT MAINLY CLEAR SKIES FOR NOW. ON FRIDAY...AVIATORS CAN EXPECTED MID AND HIGH LEVEL CLOUDS TO ADVECT ACROSS THE REGION AS THEY SPILL INTO THE REGION IN ADVANCE OF AFOREMENTIONED WARM FRONT. VFR CONDITIONS SHOULD PREVAIL. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...LATTO NEAR TERM...HICKMAN/LATTO SHORT TERM...LATTO LONG TERM...CONIGLIO AVIATION...HICKMAN/JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
954 AM EST THU JAN 17 2013 .SYNOPSIS... CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLEY RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH CLOUD CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF LOW CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED WITH MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON HOW TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY. THE HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT IN HIGH TEMPERATURES IN THE 30S. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY NIGHT AND FRIDAY. BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE UPPER 20S FOR THE MOST PART. SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE 40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH. A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER AIR ACROSS THE REGION SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS. ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO REACH 20 IN MOST LOCATIONS. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... LOW LEVEL CLOUD COVER IS SOMEWHAT TOUGH TO DISCERN THIS MORNING AS THICK CIRRUS CLOUDS ARE BLOCKING ANY HELP FROM THE IR SATELLITE IMAGES. BASED ON SURFACE OBS...IT DOES APPEAR THAT THE MVFR SC DECK IS EXPANDING ACROSS NORTHERN PORTIONS OF OUR FA. THE LATEST RAP IS INDICATING SOME DECENT 925 MB MOISTURE PUSHING DOWN ACROSS OUR AREA THROUGH AT LEAST THE REST OF THE MORNING...BUT THE 06Z NAM IS NOT AS MOIST. GIVEN THAT THE LOW LEVEL CAA WILL CONTINUE INTO THIS AFTERNOON...WOULD BE INCLINED TO THINK THE MVFR CLOUDS WOULD STICK AROUND FOR A WHILE. WILL THEREFORE BE A LITTLE SLOWER TO SCATTER THINGS OUT THIS AFTERNOON BUT DO EXPECT TO EVENTUALLY SEE AT LEAST SOME PARTIAL CLEARING. LOW LEVEL MOISTURE IS PROGGED TO INCREASE ACROSS NORTHERN OHIO AGAIN LATER TONIGHT. THIS MAY ALLOW FOR SOME SC TO SNEAK BACK DOWN TOWARD THE NORTHERN TAFS LATE IN THE PERIOD. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...LATTO NEAR TERM...HICKMAN/LATTO SHORT TERM...LATTO LONG TERM...CONIGLIO AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
637 AM EST THU JAN 17 2013 .SYNOPSIS... CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLEY RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH CLOUD CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF LOW CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED WITH MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON HOW TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY. THE HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT IN HIGH TEMPERATURES PEAKING IN THE MIDDLE 30S. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY NIGHT AND FRIDAY. BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE UPPER 20S FOR THE MOST PART. SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE 40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH. A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER AIR ACROSS THE REGION SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS. ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO REACH 20 IN MOST LOCATIONS. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... LOW LEVEL CLOUD COVER IS SOMEWHAT TOUGH TO DISCERN THIS MORNING AS THICK CIRRUS CLOUDS ARE BLOCKING ANY HELP FROM THE IR SATELLITE IMAGES. BASED ON SURFACE OBS...IT DOES APPEAR THAT THE MVFR SC DECK IS EXPANDING ACROSS NORTHERN PORTIONS OF OUR FA. THE LATEST RAP IS INDICATING SOME DECENT 925 MB MOISTURE PUSHING DOWN ACROSS OUR AREA THROUGH AT LEAST THE REST OF THE MORNING...BUT THE 06Z NAM IS NOT AS MOIST. GIVEN THAT THE LOW LEVEL CAA WILL CONTINUE INTO THIS AFTERNOON...WOULD BE INCLINED TO THINK THE MVFR CLOUDS WOULD STICK AROUND FOR A WHILE. WILL THEREFORE BE A LITTLE SLOWER TO SCATTER THINGS OUT THIS AFTERNOON BUT DO EXPECT TO EVENTUALLY SEE AT LEAST SOME PARTIAL CLEARING. LOW LEVEL MOISTURE IS PROGGED TO INCREASE ACROSS NORTHERN OHIO AGAIN LATER TONIGHT. THIS MAY ALLOW FOR SOME SC TO SNEAK BACK DOWN TOWARD THE NORTHERN TAFS LATE IN THE PERIOD. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...LATTO NEAR TERM...LATTO SHORT TERM...LATTO LONG TERM...CONIGLIO AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
421 AM EST THU JAN 17 2013 .SYNOPSIS... CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLEY RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH CLOUD CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF LOW CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED WITH MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON HOW TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY. THE HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT IN HIGH TEMPERATURES PEAKING IN THE MIDDLE 30S. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY NIGHT AND FRIDAY. BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE UPPER 20S FOR THE MOST PART. SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE 40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH. A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER AIR ACROSS THE REGION SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS. ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO REACH 20 IN MOST LOCATIONS. && .AVIATION /10Z THURSDAY THROUGH MONDAY/... A WEAKENING FRONTAL BOUNDARY WILL PUSH DOWN ACROSS THE REGION THROUGH THIS MORNING. AS IT DOES...A SC FIELD WILL OVERSPREAD THE TAF SITES OVER THE NEXT FEW HOURS. THE SOUTHERN EDGE OF THIS IS STILL VFR...BUT WE WILL LIKELY SEE SOME MVFR CIGS DEVELOP THROUGH DAYBREAK...ESPECIALLY AT THE NORTHERN TAF SITES. DRIER AIR WILL WORK IN FROM THE NORTHWEST THROUGH MID TO LATE MORNING. THIS SHOULD ALLOW LOWER CLOUDS TO SCATTER OUT WITH VFR CONDITIONS EXPECTED THROUGH THE REMAINDER OF THE TAF PERIOD. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...LATTO NEAR TERM...LATTO SHORT TERM...LATTO LONG TERM...CONIGLIO AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
330 AM EST THU JAN 17 2013 .SYNOPSIS... CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLY RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...A AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH CLOUD CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF LOW CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED WITH MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON HOW TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY. THE HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT IN HIGH TEMPERATURES PEAKING IN THE MIDDLE 30S. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY NIGHT AND FRIDAY. BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE UPPER 20S FOR THE MOST PART. SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE 40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH. A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER AIR ACROSS THE REGION SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS. ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO REACH 20 IN MOST LOCATIONS. && .AVIATION /08Z THURSDAY THROUGH MONDAY/... A WEAKENING FRONTAL BOUNDARY WILL PUSH DOWN ACROSS THE REGION THROUGH THIS MORNING. AS IT DOES...A SC FIELD WILL OVERSPREAD THE TAF SITES OVER THE NEXT FEW HOURS. THE SOUTHERN EDGE OF THIS IS STILL VFR...BUT WE WILL LIKELY SEE SOME MVFR CIGS DEVELOP THROUGH DAYBREAK...ESPECIALLY AT THE NORTHERN TAF SITES. DRIER AIR WILL WORK IN FROM THE NORTHWEST THROUGH MID TO LATE MORNING. THIS SHOULD ALLOW LOWER CLOUDS TO SCATTER OUT WITH VFR CONDITIONS EXPECTED THROUGH THE REMAINDER OF THE TAF PERIOD. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...LATTO NEAR TERM...LATTO SHORT TERM...LATTO LONG TERM...CONIGLIO AVIATION...JGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
528 PM EST THU JAN 17 2013 .SYNOPSIS... AN ARCTIC FRONTAL BOUNDARY WILL SAG INTO NORTHERN PENNSYLVANIA THIS EVENING. AT THE SAME TIME...A DEVELOPING STORM WILL PASS JUST TO THE SOUTH OF THE STATE. AFTER A COLD DAY ON FRIDAY... TEMPERATURES WILL MODERATE A BIT ON SATURDAY BEFORE A SHOT OF MUCH COLDER AIR ARRIVES SUNDAY. TEMPERATURES WILL DIP TO NEAR OR BELOW ZERO IN PARTS OF THE AREA NEXT WEEK AS THE COLDEST AIR OF THE SEASON MOVES IN. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 5 PM UPDATE... THICK...MULTI-LAYERED CLOUD SHIELD CONTINUES TO STREAM NE OVER THE AREA FROM THE DEVELOPING WAVE OVER THE SERN US. NRN EDGE OF THE PRECIP IS ACROSS SRN WVA AND NRN VA /JUST SOUTH OF THE D.C. AREA/. HRRR AND 4KM NAM SHOWS THE NRN EDGE OF THE PRECIP REMAINING STATIONARY THEN SAGGING SLOWLY SOUTH AND EAST THROUGH THIS EVENING. THIS AGREES WITH THE LATEST TRENDS ON THE KLWX 88D. MAIN CONCERN FOR THIS EVENING FOR ANY MEASURABLE PRECIP WILL BE INVOF A SLOW MOVING EAST/WEST ARCTIC BOUNDARY DRAPED ACROSS SOUTHERN NEW YORK. SOME VERY WEAK...AND FLEETING ISENTROPIC LIFT NEAR THE 275K THETA SFC /AHEAD OF A WEAK WAVE OF LOW PRESSURE ALONG THE BOUNDARY/ WILL SUPPORT AN AREA OF LIGHT SNOW POSSIBLY DRIFTING SOUTH OF THE PENN/NY BORDER. A LIGHT COATING OF SNOW IS POSSIBLE NEAR AND TO THE NORTH OF ROUTE 6. THIS FRONT WILL FOLLOWED BY SOME LAKE EFFECT SNOW SHOWERS ACRS NWRN PENN BY MIDNIGHT. THE SNOW SHOWERS SHOULD CONTINUE INTO FRIDAY MORNING. STRATO CU CLOUD TEMPS BENEATH THE SUBSIDENCE INVERSION /THAT WILL BRIEFLY POKE UP TO AROUND 7-8 KFT AGL THIS EVENING/ WILL BE IN THE FAVORABLE DENDRITIC GROWTH ZONE...SO SOME NARROW SNOW BANDS COULD DROP A QUICK INCH OR TWO NEAR AND TO THE WEST OF KBFD. ELSEWHERE ACROSS THE CENTRAL MTNS AND SUSQ VALLEY REGION...NOTHING MORE THAN SOME FLURRIES ARE POSSIBLE. TEMPS THIS EVENING WILL VARY FROM THE MID AND UPPER 20S ALONG THE PA/NY BORDER...TO THE LOWER AND MID 30S THROUGHOUT THE CENTRAL AND SOUTHERN VALLEYS. LOWS TONIGHT WILL BE VERY NEAR TO SLIGHTLY BELOW NORMAL. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... LATEST GUIDANCE STILL KEEPS THE SRN STREAM SYSTEM ROLLING TO THE EAST-NORTHEAST...KEEPING THE THREAT OF PRECIP SOUTH OF THE MASON- DIXON LINE. THE WAVE IS MADE TO DEEPEN OFF SHORE FRIDAY AS IT SPEEDS AWAY...BEING REPLACED BY A STRONG HIGH FROM THE TN VALLEY. CLEARING IS POSSIBLE ON FRIDAY AS THE ADVECTION CHANGES SIGN IN THE AFTN...AND WE SEE THE ARCTIC AIR BEAT A QUICK RETREAT OFF TO THE NORTHEAST AS THE FLOW GOES SW ON THE BACK SIDE OF THE HIGH. DESPITE THE WARM ADVECTION THAT IS EXPECTED TO DEVELOP DURING THE DAY...HIGHS IN THE 20S AND 30S WILL STILL AVERAGE WELL BELOW NORMAL. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... SFC HIGH PRES WILL SLIDE ENEWD FROM THE TN VLY INTO THE SRN MID ATLC FRIDAY EVENING BEFORE EXPANDING ACRS THE SE STATES INTO SATURDAY. A STRONG AND RELATIVELY MILD SWLY LLVL FLOW /40-50KT LLJ/ IN-BTWN THE AFOREMENTIONED SFC HIGH AND CLIPPER LOW CROSSING THE UPPER GRT LKS WILL PRODUCE STG LOW-MID LVL WAA...PUSHING 850MB TEMPS ABV 0C IN MOST AREAS ON SAT. THIS SHOULD RESULT IN A BRIEF WARM-UP ON SATURDAY WITH HIGHS PROJECTED TO CLIMB SEVERAL DEGREES ABV NORMAL. H5 SHORTWAVE TROUGH AND ASSOCD CLIPPER SFC LOW WILL TRACK EWD ACRS SRN ONTARIO INTO THE ST. LAWRENCE RIVER VALLEY SAT NGT INTO EARLY SUNDAY. MODELS REMAIN IN GOOD AGREEMENT IN PLOWING AN ARCTIC FRONT SEWD ACRS THE CWA EARLY SUNDAY WITH TEMPS ALOFT PLUMMETING TO -10 TO -15C AT 850MB BY 00Z MONDAY. THE POTNL MAY EXIST FOR HIGH IMPACT SUB-ADVY /HISA/ SNOW SQUALLS WITH THE ARCTIC FROPA...WHICH COULD CAUSE RAPID WHITE-OUT CONDS. SOME LAKE EFFECT SNOW SHOWERS ARE ALSO POSSIBLE OVER THE NW MTNS. *THE NDFD WEB GRAPHICS SHOW "HEAVY SNOW" FOR SAT NGT/EARLY SUNDAY. WE ARE NOT EXPECTING HEAVY SNOW IN A LITERAL SENSE...BUT HAVE INSERTED +SW /HEAVY SQUALLS/ INTO THE GRIDS WHICH GETS TRANSLATED INTO HEAVY SNOW ON THE NDFD WEB GRAPHICS.* HEAVY SNOW SQUALLS PRODUCE INTENSE BURSTS OF SNOW WITH ACCUMS GENERALLY LESS THAN 1" OVER A SHORT DURATION. MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE REMAINS IN VERY GOOD AGREEMENT IN DEPICTING A DEEP TROUGH OVER THE ERN U.S....WITH A VERY COLD POLAR VORTEX /-40C AT 500MB/ SITUATED OVER HUDSON BAY. THE STRONG COLD SIGNAL IN THE LARGE SCALE PATTERN WILL SUPPORT HIGH CONFIDENCE IN BELOW NORMAL TEMPERATURES THROUGH THE PERIOD. PRELIM DAY 4-7 MAX/MIN TEMPS WERE DERIVED USING AN EVEN BLEND OF 17/00Z HPC/NAEFS/GFS/ECMWF MOS DATA. INITIAL VERIFICATION OF THE EXPERIMENTAL 00Z ECMWF MOS DATA HAS SHOWN INCREASED SKILL OVER THE GFS-BASED GUIDANCE AT THIS RANGE...AND IS NOTABLY COLDER EARLY NEXT WEEK WHEN TEMPS SHOULD REACH THEIR BOTTOM...WITH -20C AIR AT H85. FINAL AFTN TEMPS WERE NUDGED TOWARD THE 12Z GMOS WHICH RESULTED IN ONLY MINOR CHANGES TO PRELIM FCST. THE WELL-ADVERTISED MODIFIED ARCTIC OUTBREAK WILL DELIVER THE COLDEST AIR OF THE SEASON TO THE AREA...ARRIVING ON SCHEDULE AS WE ENTER THE HEART OF CLIMATOLOGICAL WINTER. THE UPPER LEVEL RIDGE IN THE WEST IS PROJECTED TO BREAK-DOWN BY THE END OF THE PERIOD...AND SHOULD ALLOW FOR SOME MODERATION INTO THE SECOND HALF OF NEXT WEEK. THE GFS REMAINS SLIGHTLY FASTER THAN THE NON-NCEP GUID IN LIFTING THE BASE OF THE ERN TROUGH NWD AT DAY 7-8. PRECIPITATION DURING THE PERIOD WILL BE LIMITED/CONFINED MAINLY TO THE WESTERN HIGH TERRAIN...WITH WEAK CLIPPERS REINFORCING THE COLD NWLY FLOW. && .AVIATION /22Z THURSDAY THROUGH TUESDAY/... MVFR CIGS WILL CONTINUE OVER MAINLY THE NORTHWEST MOUNTAINS TONIGHT. KJST AND VCNTY WILL LIKELY SEE VFR FOR THE FIRST HALF OF TONIGHT...FOLLOWED BY MVFR CIGS LATE. LAKE MOISTURE CLIMBING THE HIGH TERRAIN OF THE NORTHWEST WILL KEEP THE CHANCE OF SNOW SHOWERS AND LOCALLY REDUCED CONDITIONS IN THE PICTURE INTO AT LEAST MID DAY FRIDAY...WITH IMPROVEMENT EXPECTED BY FRIDAY AFTERNOON AND EVENING AS WINDS TURN MORE SOUTHWESTERLY ON THE BACK SIDE OF A RETREATING HIGH. OUTLOOK... FRI...AM -SHSN/MVFR CIGS POSS W MTNS. SAT...NO SIG WX EXPECTED. SUN-TUE...SHSN/MVFR POSS W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE/LAMBERT NEAR TERM...LA CORTE/LAMBERT SHORT TERM...LA CORTE LONG TERM...STEINBUGL AVIATION...LA CORTE/LAMBERT
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1001 AM EST THU JAN 17 2013 .SYNOPSIS... A WEAK COLD FRONT WILL PRESS IN FROM THE NORTHWEST TODAY. AT THE SAME TIME...A STORM SYSTEM WILL PASS JUST TO THE SOUTH OF THE STATE. AFTER A COLD DAY ON FRIDAY...TEMPERATURES WILL MODERATE A BIT ON SATURDAY BEFORE MUCH COLDER AIR ARRIVES SUNDAY. TEMPERATURES WILL DIP TO NEAR OR BELOW ZERO IN PARTS OF THE AREA NEXT WEEK AS THE COLDEST AIR OF THE SEASON MOVES IN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 10 AM UPDATE... THICK CLOUD COVER CONTINUES TO STREAM NE OVER THE AREA FROM THE DEVELOPING WAVE OVER THE SERN US. NRN EDGE OF THE PRECIP JUST MAKING INTO SOUTHERN DELAWARE...SHOULD REMAIN SOUTH OF THE BORDER TODAY. ELSEWHERE OVER THE NW SOME PATCHY FREEZING DRIZZLE IS POSSIBLE OVER SOME OF THE RIDGES...OTHERWISE NOTHING MORE THAN A FEW SCATTERED LIGHT SNOW SHOWERS WILL OCCUR. THE ABUNDANCE OF CLOUDS AND THE COLD AIR ADVECTION TODAY WILL CAUSE TEMPS TO STAY RATHER STEADY OVER MUCH OF THE AREA...AND EVEN DROP A FEW DEGS IN THE NWRN THIRD OF THE AREA. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... GFS AND NAM KEEP THE SRN STREAM SYSTEM ROLLING TO THE EAST AND NEVER REALLY THREATEN OUR SERN COS WITH PRECIP. ECMWF AND ONE OR TWO MEMBERS OF THE GEFS STILL NUDGE VERY LIGHT PRECIP INTO THE EXTREME SE...WHICH IS JUST ENOUGH TO KEEP A 20 POP THERE FOR THE EVENING. BUT THEN THE WAVE DEEPENS OFF SHORE AND PULLS IN THE COLD AIR FOR FRIDAY. CLEARING IS POSSIBLE ON FRIDAY AS THE ADVECTION CHANGES SIGN IN THE AFTN...RAISING THE 8H TEMPS 10C IN JUST 3-4HRS. THE NW FLOW ALOFT KEEPS IT ACTIVE AND UNSETTLED THROUGH THE PERIOD. THE 1035MB HIGH OFF TO OUR SOUTH AND 8H TEMPS RISING INTO THE BLACK ON SAT WILL MAKE IT VERY LIKELY THAT WE WILL ECLIPSE NORMAL MAXES BY 5 TO 10F ON SAT. THE MOST INTERESTING PERIOD OF THE ENTIRE FORECAST IS SAT NIGHT AND SUNDAY MORNING. TIMING OF A VERY STRONG/RAPID CHANGE IN AIR MASS IS FAIRLY CONSISTENT AMONG THE NUMERICAL GUIDANCE. THE FRONT WILL BLOW THROUGH SOMETIME AROUND OR AFTER MIDNIGHT IN THE NW AND SHORTLY AFTER SUNRISE IN THE SE. THIS SORT OF SET UP IS VERY FAVORABLE FOR INTENSE SNOW SHOWERS/SQUALLS. HOWEVER...THE EXPECTED NIGHTTIME PASSAGE COULD LESSEN THE INTENSITY OF ANY SQUALLS WITHOUT THE MODEST INCREASE IN INSTABILITY/MIXING POSSIBLE DURING THE DAYLIGHT HOURS. ANOTHER POSITIVE THING IS THAT IT SHOULD OCCUR IN THE OVERNIGHT AND NOT EVEN ON A SCHOOL/WORK-DAY MORNING. HAVE CONTINUED THE MENTION OF THE POSSIBILITY OF SQUALLS IN THE HWO...DUE TO THE POTENTIAL TRAVEL IMPACT RATHER THAN ANY HARD AND FAST SNOW OR ICE CRITERIA. TEMPS DROP BACK ON SUNDAY TO 5 OR 10F BELOW NORMALS. HAVE ALLOWED FOR JUST A FEW DEG RISE IN TEMPS...BUT IT COULD BE ANOTHER STEADY OR SLIGHT DROP DURING THE DAYLIGHT HRS. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... THE PATTERN LOOKS COLD HEADING INTO NEXT WEEK WITH HIGH CONFIDENCE IN BELOW NORMAL TEMPERATURES. ASIDE FROM OCNL LAKE EFFECT SNOW SHOWERS AND SCT FLURRIES...PRECIPITATION SHOULD BE HARD TO COME BY WITH VERY DRY MODIFIED ARCTIC AIR PERSISTING THRU THE END OF THE PD. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... A SURGE OF HIGHER MOISTURE AHEAD OF APPROACHING COLD FRONT WILL ASCEND THE W MTNS...PRODUCING A PERIOD OF IFR CIGS AT BFD AND JST EARLY THIS AM. ACROSS THE RIDGE/VALLEY REGION...MVFR CIGS BEING REPORTED AT AOO/UNV/IPT AT 11Z. COLD FRONT WILL PUSH THRU CENTRAL PA LATER THIS MORNING...USHERING IN A DRIER AIR MASS AND RISING CIGS. LATEST RAP LOW LVL MOISTURE FIELDS SUGGEST BFD WILL RISE TO MVFR CIGS BTWN 12Z-13Z AND JST WILL FOLLOW BY ARND 14Z. IN THE WAKE OF THE FRONT...MOISTURE FROM LK ERIE WILL ASCEND THE NW MTNS...LIKELY RESULTING IN MVFR CIGS PERSISTING AT BFD UNTIL AT LEAST MID AFTN. FURTHER SOUTH...SOUNDINGS SUGGEST THE POSSIBILITY OF LINGERING MVFR CIGS AT JST/UNV/AOO THRU ARND MIDDAY. HOWEVER...DOWNSLOPING FLOW ACROSS THE SUSQ VALLEY SHOULD ENSURE VFR CONDS AT MDT AND LNS THROUGH TODAY. OUTLOOK... FRI...AM -SHSN/MVFR CIGS POSS W MTNS. SAT...NO SIG WX EXPECTED. SUN-MON...SHSN/MVFR POSS W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO/LA CORTE NEAR TERM...DANGELO/LA CORTE SHORT TERM...DANGELO LONG TERM...STEINBUGL AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
641 AM EST THU JAN 17 2013 .SYNOPSIS... A WEAK COLD FRONT WILL PRESS IN FROM THE NORTHWEST TODAY. AT THE SAME TIME...A STORM SYSTEM WILL PASS JUST TO THE SOUTH OF THE STATE. AFTER A COLD DAY ON FRIDAY...TEMPERATURES WILL MODERATE A BIT ON SATURDAY BEFORE MUCH COLDER AIR ARRIVES SUNDAY. TEMPERATURES WILL DIP INTO THE SINGLE DIGITS IN PARTS OF THE AREA NEXT WEEK AS THE COLDEST AIR OF THE SEASON MOVES IN. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 6 AM... TEMPS STILL AROUND 40 ALONG THE SRN BORDER...BUT WIND HAS VEERED SLIGHTLY. THE HIGH CLOUDS ARE THICK ENOUGH TO MAKE VIRGA SEEN ON THE RADAR AND REMARKED IN OBS AT KMDT. LOW CLOUDS COVER MOST OF THE AREA NOW. A COLD FRONT IS DROPPING ACROSS THE LOWER GREAT LAKES AND WILL TURN THE WINDS MORE NORTHERLY SOON. ENOUGH FRICTION/MOISTURE FLUX WILL CREATE SHSN IN THE NW...BUT ANY ACCUMS SHOULD STAY IN THE SNOW BELT THIS MORNING OR EARLY AFTN. A FEW FLURRIES COULD GET OFF THE ALLEGHENIES...BUT WILL NOT MENTION MUCH S OR E OF CLEARFIELD AND WELLSBORO. THE ABUNDANCE OF CLOUDS AND THE COLD AIR ADVECTION TODAY WILL CAUSE TEMPS TO STAY RATHER STEADY OVER MUCH OF THE AREA...AND EVEN DROP A FEW DEGS IN THE NWRN THIRD OF THE AREA. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... GFS AND NAM KEEP THE SRN STREAM SYSTEM ROLLING TO THE EAST AND NEVER REALLY THREATEN OUR SERN COS WITH PRECIP. ECMWF AND ONE OR TWO MEMBERS OF THE GEFS STILL NUDGE VERY LIGHT PRECIP INTO THE EXTREME SE...WHICH IS JUST ENOUGH TO KEEP A 20 POP THERE FOR THE EVENING. BUT THEN THE WAVE DEEPENS OFF SHORE AND PULLS IN THE COLD AIR FOR FRIDAY. CLEARING IS POSSIBLE ON FRIDAY AS THE ADVECTION CHANGES SIGN IN THE AFTN...RAISING THE 8H TEMPS 10C IN JUST 3-4HRS. THE NW FLOW ALOFT KEEPS IT ACTIVE AND UNSETTLED THROUGH THE PERIOD. THE 1035MB HIGH OFF TO OUR SOUTH AND 8H TEMPS RISING INTO THE BLACK ON SAT WILL MAKE IT VERY LIKELY THAT WE WILL ECLIPSE NORMAL MAXES BY 5 TO 10F ON SAT. THE MOST INTERESTING PERIOD OF THE ENTIRE FORECAST IS SAT NIGHT AND SUNDAY MORNING. TIMING OF A VERY STRONG/RAPID CHANGE IN AIR MASS IS FAIRLY CONSISTENT AMONG THE NUMERICAL GUIDANCE. THE FRONT WILL BLOW THROUGH SOMETIME AROUND OR AFTER MIDNIGHT IN THE NW AND SHORTLY AFTER SUNRISE IN THE SE. THIS SORT OF SET UP IS VERY FAVORABLE FOR INTENSE SNOW SHOWERS/SQUALLS. HOWEVER...THE EXPECTED NIGHTTIME PASSAGE COULD LESSEN THE INTENSITY OF ANY SQUALLS WITHOUT THE MODEST INCREASE IN INSTABILITY/MIXING POSSIBLE DURING THE DAYLIGHT HOURS. ANOTHER POSITIVE THING IS THAT IT SHOULD OCCUR IN THE OVERNIGHT AND NOT EVEN ON A SCHOOL/WORK-DAY MORNING. HAVE CONTINUED THE MENTION OF THE POSSIBILITY OF SQUALLS IN THE HWO...DUE TO THE POTENTIAL TRAVEL IMPACT RATHER THAN ANY HARD AND FAST SNOW OR ICE CRITERIA. TEMPS DROP BACK ON SUNDAY TO 5 OR 10F BELOW NORMALS. HAVE ALLOWED FOR JUST A FEW DEG RISE IN TEMPS...BUT IT COULD BE ANOTHER STEADY OR SLIGHT DROP DURING THE DAYLIGHT HRS. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... THE PATTERN LOOKS COLD HEADING INTO NEXT WEEK WITH HIGH CONFIDENCE IN BELOW NORMAL TEMPERATURES. ASIDE FROM OCNL LAKE EFFECT SNOW SHOWERS AND SCT FLURRIES...PRECIPITATION SHOULD BE HARD TO COME BY WITH VERY DRY MODIFIED ARCTIC AIR PERSISTING THRU THE END OF THE PD. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... A SURGE OF HIGHER MOISTURE AHEAD OF APPROACHING COLD FRONT WILL ASCEND THE W MTNS...PRODUCING A PERIOD OF IFR CIGS AT BFD AND JST EARLY THIS AM. ACROSS THE RIDGE/VALLEY REGION...MVFR CIGS BEING REPORTED AT AOO/UNV/IPT AT 11Z. COLD FRONT WILL PUSH THRU CENTRAL PA LATER THIS MORNING...USHERING IN A DRIER AIR MASS AND RISING CIGS. LATEST RAP LOW LVL MOISTURE FIELDS SUGGEST BFD WILL RISE TO MVFR CIGS BTWN 12Z-13Z AND JST WILL FOLLOW BY ARND 14Z. IN THE WAKE OF THE FRONT...MOISTURE FROM LK ERIE WILL ASCEND THE NW MTNS...LIKELY RESULTING IN MVFR CIGS PERSISTING AT BFD UNTIL AT LEAST MID AFTN. FURTHER SOUTH...SOUNDINGS SUGGEST THE POSSIBILITY OF LINGERING MVFR CIGS AT JST/UNV/AOO THRU ARND MIDDAY. HOWEVER...DOWNSLOPING FLOW ACROSS THE SUSQ VALLEY SHOULD ENSURE VFR CONDS AT MDT AND LNS THROUGH TODAY. OUTLOOK... FRI...AM -SHSN/MVFR CIGS POSS W MTNS. SAT...NO SIG WX EXPECTED. SUN-MON...SHSN/MVFR POSS W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...STEINBUGL AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
102 AM EST THU JAN 17 2013 .SYNOPSIS... A COLD FRONT WILL CONTINUE TO DRIFT SLOWLY THROUGH THE REGION INTO TONIGHT. LOW PRESSURE IS FORECAST DEVELOP OVER THE EASTERN GULF OF MEXICO AND MOVE NORTHEAST ALONG THE FRONT ON THURSDAY. AS THE LOW MOVES OFF THE NORTH CAROLINA COAST THURSDAY NIGHT...THE WEATHER WILL BE DRIER AND SEASONABLY COOL FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF MIDNIGHT...COLD WEDGE APPEARS TO BE HOLDING STRONG AND THIS SHOULD LARGELY INHIBIT WARM AIR ALOFT FROM MAKING MUCH FURTHER PUSH NORTHWARD INTO THE CWFA. RAP 925MB TEMP PROGS FOR THE REST OF THE NIGHT SHOW SLIGHT WARMING IN THE COUNTIES NEAR/ALONG OUR SOUTHEAST BORDER WHILE COLD ADVECTION IS CLEARLY GETTING UNDERWAY OVER THE MTNS AND NRN NC PIEDMONT. TEMP/DEWPT TRENDS HAVE BEEN REVISED USING THE RAP SFC TEMPS WHICH WERE IN FAIRLY GOOD AGREEMENT WITH 12 AM ANALYZED OBS AND AGREE WITH THE 925MB PATTERN. AS OF 10 PM...OVER THE COURSE OF THE EVENING I HAVE BEEN MONITORING TRENDS IN THE MODEL GUIDANCE AND UPDATING THE FORECAST ACCORDINGLY. TWO TRENDS HAVE OCCURRED...GUIDANCE IS WETTER AND SLIGHT QUICKER WITH COOLING TEMPS LATE TOMORROW AFTERNOON AND EVENING. IN SHORT...THE POTENTIAL FOR HEAVY SNOW HAS INCREASED ACROSS THE NC MTNS...REMAINING AROUND THE SAME AS THE PREVIOUS PACKAGE EAST. LATEST WATER VAPOR IMAGERY INDICATES THAT THE H5 LOW OVER ARKLATX REGION HAS STARTED TO TRANSITION FROM A POSITIVE TILTED TROUGH TO MORE NEUTRAL. AHEAD OF THE LOW...A RIBBON OF 1.2 INCH PW EXTENDED FROM THE YUCATAN PENINSULA ACROSS THE FL PANHANDLE TO THE SOUTHERN APPALACHIANS. THE PW VALUES ARE NEARLY 200 PERCENT OF NORMAL. AS THE H5 LOW APPROACHES TONIGHT...A SFC LOW IS EXPECTED TO RAPIDLY DEEPEN AND ORGANIZE ACROSS CENTRAL GA. AS THE LOW DEEPENS...LLVL FLOW WILL INCREASE...SUPPORTING A WARM FRONT/WEDGE BOUNDARY ACROSS THE PIEDMONT OF THE CAROLINAS. NAM12 INDICATES THAT A SW TO NE BAND OF 925-850MB FRONTOGENESIS WILL DEVELOP DURING THE PRE DAWN HOURS. IN ADDITION...H7 QG UPWARD VERTICAL VELOCITIES WILL INCREASE TO NEAR 15 MBS/HR. THE COMBINATION OF RICH MOISTURE AND DEEPENING LIFT WILL SUPPORT THE DEVELOPMENT OF A BAND OF MODERATE RAIN ACROSS THE FOOTHILLS AND PIEDMONT LATE TONIGHT. TEMPERATURES MAY SLOWLY RISE OR REMAIN STEADY OVERNIGHT...UNDER WAA ALOFT. PRECIP WILL FALL AS RAIN. POPS WERE INCREASE OVERNIGHT. DYNAMICS ACROSS THE SOUTHERN APPALACHIAN REGION WILL INCREASE SHARPLY AFTER SUNRISE AS THE TILTED LOW PRESSURE SYSTEM BEGINS TO MOVE EASTWARD. A WIDE DEFORMATION ZONE SHOULD PIVOT OVER THE NC MTNS THROUGH MID DAY...THEN BEGIN TO SHIFT EAST DURING THE AFTERNOON AND EVENING. BY 18Z...THE CORE OF H7 QG UPWARD VERTICAL VELOCITIES WILL RAPIDLY INCREASE TO 40 MBS/HR AND TRACK SE TO NE ACROSS THE MIDDLE OF THE FORECAST AREA...FRONTOGENESIS PEAKS DURING THIS PERIOD. IN ADDITION...THE NAM12 INDICATES THAT A BROAD FIELD OF NEGATIVE SATURATED GEO POTENTIAL VORTICITY WILL DEVELOP AHEAD OF H7 LOW...POSSIBLY SIGNALING THE EXISTENCE OF INSTABILITY. GIVEN THE ENVIRONMENT AND DURATION OF STRONG FORCING...I UPDATE THE FORECAST TO INCREASE QPF BY AN INCH...INCREASE POPS TO 100 PERCENT. TEMPERATURES ARE VERY CHALLENGING...BUT I ADJUST CONTINUOUS COOLING TREND WITH THE NAM 2M TEMPS. USING THIS APPROACH...PRECIP SHOULD BEGIN TO TRANSITION TO SN/IP ACROSS THE TN BORDER AFTER 18Z. THE SNOW LINE WILL ADVANCE TO THE FOOTHILLS BY 0Z. THE GFS AND NAM INDICATE THAT THE DEFORMATION ZONE WILL REMAIN OVER THE CWA THROUGH THURS EVENING...MOVING EAST OF THE CWA BY EARLY FRI MORNING. TEMPERATURES WILL DECREASE STEADILY THROUGH THE PERIOD. HOWEVER...IT APPEARS THAT ONLY A 3 TO 6 HOUR WINDOW WILL EXIST EAST OF THE MTNS FOR ACCUMULATING SN...GIVEN THE RAPID DECREASE IN MOISTURE ALOFT AND FORCING. I HAVE UPDATED THE STORM TOTAL SNOW FORECAST TO INCREASE SNOWFALL ACROSS THE MTNS BY A COUPLE OF INCHES...AREAS EAST REMAIN VERY SIMILAR TO THE PREVIOUS FORECAST. THE WINTER STORM PRODUCTS AND FLOOD WATCH APPEAR TO BE WELL PLACED AND TIMED. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/... AS OF 315 PM WEDNESDAY...A NE TO SW ORIENTED DEEP LAYER FRONTAL BOUNDARY REMAINS STALLED OVER THE WESTERN CAROLINAS AND NE GA. PW VALUES ALONG THE BNDRY CONTINUE TO RUN 200 TO 300 PERCENT OF NORMAL. IN FACT...NESTS MENTIONED THIS MORNING THAT FFC/S SOUNDING THIS MORNING HAD IT/S 4TH HIGHEST RECORDED JANUARY PW VALUE. SO THAT SAY THAT THERE IS A SIGNIFICANT AMOUNT OF MOISTURE IN PLACE OVER THE REGION IS AN UNDERSTATEMENT. A POTENT UPPER LOW OVER ERN TX THIS EVENING WILL TAKE ON A NEGATIVE TILT AND LIFT ACROSS THE UPSTATE BY TOMORROW EVENING. THE NUMERICAL MODELS GENERATE VERY HEAVY RAIN WITH THIS FEATURE. QPF AVERAGES AROUND 3 INCHES OVER MUCH OF THE SRN AND ERN NC MTNS...THE FOOTHILLS AND THE WESTERN PIEDMONT. CONSIDERING THE AMAZING AMOUNT OF RAIN SOME MOUNTAIN LOCATIONS HAVE HAD OVER THE PAST THREE DAYS...THIS EXTRA SHOT OF RAIN IS LIKELY TO CAUSE A CONSIDERABLE AMOUNT OF STREAM AND RIVER FLOODING. THEREFORE THE FLOOD WATCH WILL BE EXPANDED ACROSS THE REST OF THE MOUNTAINS AND FOOTHILLS OF THE WESTERN CAROLINAS AND NORTHEAST GEORGIA. WE COULD SEE SOME VERY HIGH RAINFALL RATES AS THE WARM CONVEYOR BELT WORKS ACROSS THE FA DURING THE DAYTIME TMRW. A TSTM ISN/T OUT OF THE QUESTION. CONSIDERING THE EXPECTED RATES...SOME OF THE FLOODING MAY BE MORE OF THE FLASH FLOOD VARIETY. IN FACT...I/M STILL DEBATING IF WE WILL ISSUE THE NEW WATCH AS A FLOOD OR FLASH FLOOD PRODUCT. THE OTHER CONCERN AS THE LOW PASSES WILL BE SNOWFALL. THE AIRMASS AHEAD OF THE LOW IS VERY WARM AND MOIST. IT WILL TAKE A WHILE FOR THE PCPN TO CHANGE OVER TO SNOW. I WOULDN/T EXPECT ANY SNOW TO DEVELOP UNTIL 18 TO 21 UTC ACROSS THE HIGHER MOUNTAIN ELEVATIONS. THE SNOW LEVELS WILL THEN QUICKLY DROP AND WORK EASTWARD WITH TIME. THE SREF PLUME DIAGRAMS ARE SHOWING WINTER STORM CRITERIA SNOWFALL AT ASHEVILLE AND EVEN AT HICKORY. I HAVE UPGRADED THE WINTER STORM WATCH TO A WARNING ACROSS MOST OF THE NC MTNS. OVER THE SOUTHWEST MOUNTAINS THE WARMING WILL BE IN EFFECT FOR ELEVATIONS ABOVE 3500 FEET. BY THE TIME THE SNOW LEVEL MAKES IT TO THE VALLEY FLOORS IN THOSE AREAS...I EXPECT THE HEAVIEST PCPN WILL HAVE ENDED. THE NORTHERN MOST PART OF THE UPSTATE AND NE GA HAVE BEEN INCLUDED IN A WINTER WEATHER ADVISORY FOR TOMORROW NIGHT. ONLY AROUND AN INCH OF SNOW IS IN THE GRIDS...BUT IF THE NAM/S STRONGER...SLOWER AND COLDER DEFORMATION ZONE VERIFIES...WE COULD SEE HEAVIER HEAVIER SNOW IN THESE LOCATIONS IN WELL. I AM MORE CONFIDENT IN THE NAM TONIGHT AS THE IT AND THE GFS HAVE COME INTO MUCH BETTER AGREEMENT. OVER THE NORTH CAROLINA ZONES...THE NAM AND MANY SREF MEMBERS INDICATE A PERIOD OF SNOW ACROSS THE FOOTHILLS AND PIEDMONT DURING THE EVENING HOURS. A CROSS SECTION THROUGH THE NAM SHOWS A DEEP LAYER NEGATIVE EPV FROM 00-03 UTC. THIS IMPLIES THE POTENTIAL FOR HEAVY BANDED PRECIPITATION WHICH WILL HELP TO LOWER SNOW LEVELS. IN FACT...AT THIS POINT I/D SAY CONFIDENCE IS GOOD THAT PARTS OF THE PIEDMONT WILL SEE SNOW...THOUGH ACCUMULATING SNOW MAY BE CONFINED TO A NARROW BAND UNDER THE BEST CSI. THE RALEIGH OFFICE IS THINKING ALONG THE SAME LINES AND WE HAVE ISSUED A WINTER STORM WATCH FOR THESE AREAS STARTING AT 21 UTC TOMORROW. EVEN WITH WARM GROUND...HEAVY SNOWFALL RATES COULD CAUSE TRAVEL CONCERNS AND MAY BREAK SOME LIMBS CAUSING POWER OUTAGES. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... AS OF 230 PM WEDNESDAY...A BROAD TROUGH WILL BE IN PLACE ACROSS THE ERN CONUS THROUGH THE WEEKEND AS A SHARP WAVE ROUNDS THE POLAR VORTEX AND CROSSES THE GREAT LAKES. A COLD FRONT WILL MOVE THROUGH THE REGION ON SUNDAY...BUT IT SHOULD BE DRY OTHER THAN SHALLOW W TO NW UPSLOPE FLOW MOISTURE INTO THE WRN MTNS PRODUCING SOME CLOUDS LATE SUNDAY. REINFORCING ENERGY WILL DIVE SE THROUGH THE MIDWEST ON MON AND PASS MAINLY N OF THE FORECAST AREA MON NIGHT THROUGH TUE. BRIEFLY COUPLED JET DIVERGENCE WILL BE POSSIBLE DURING THE MON NIGHT TIME FRAME...BUT MOISTURE WILL BE TOO SHALLOW FOR ANYTHING OTHER THAN SLIGHT CHANCES OF UPSLOPE SNOW SHOWERS IN THE WRN MTNS. REINFORCING ARCTIC AIR WILL THEN ARRIVE BEHIND THE FRONT EARLY TUE THROUGH WED...WITH DEEP LAYER NW FLOW THROUGH THE PERIOD ALONG WITH DRY CONDITIONS. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... AT KCLT AND KHKY...THE FIRST 6 HOURS OR SO OF THE PERIOD WILL LIKELY BE MARKED BY VERY MESSY CONDITIONS...WITH CIGS AND VISBY BOUNCING BACK AND FORTH BETWEEN VARIOUS FLT CATEGORIES. TOWARD DAYBREAK... CONDITIONS SHOULD SETTLE INTO THE IFR/LIFR RANGE...AS STRONG LOW LEVEL LIFT DEVELOPS IN RESPONSE TO STRONG UPPER LEVEL STORM SYSTEM MOVING OUT OF THE LOWER MISS VALLEY. IN THE INTERIM...ONE AREA OF LIGHT/MOD RAIN WILL PUSH EAST OF THE TERMINALS BY AROUND 07Z. HOWEVER...ANOTHER ONE WILL APPROACH BETWEEN 09 AND 10Z. WHILE VISBY WILL LIKELY IMPROVE IN BETWEEN THESE WAVES OF PRECIP...THE GENERAL IDEA IS THAT CIGS WILL REMAIN (OR RETURN TO) LIFR. VERY POOR FLT CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE DAY. PERIODS OF HEAVY RAIN ARE EXPECTED DURING THE DAYLIGHT HOURS...LIKELY RESULTING IN LONG DURATION OF IFR/LIFR VISBY. STRENGTHENING NE WINDS WILL DEVELOP AS LOW PRESSURE INTENSIFIES TO THE SOUTHWEST...WITH GUSTS IN THE 20S LIKELY BY AFTERNOON. FINALLY...RAIN IS EXPECTED TO CHANGE TO SNOW THURSDAY EVENING...WITH LIGHT ACCUMULATIONS POSSIBLE...ESP AT KHKY. ELSEWHERE...ONE WAVE OF LIGHT/MOD RAIN HAS SHIFTED EAST OF THE TERMINALS...BUT ANOTHER WILL MOVE BACK OVER THE AREA BETWEEN 7 AND 9 Z. VISBY IS EXPECTED TO BRIEFLY IMPROVE TO VFR PRIOR TO THE ARRIVAL OF THE NEXT WAVE. HOWEVER...CIGS ARE A BIT MORE PROBLEMATIC. THE IMPROVEMENT IN CIGS THAT WAS OBSERVED EARLIER WAS TIED TO THE ONSET OF PRECIP...AND CIGS MAY VERY WELL RETURN TO LIFR/IFR PRIOR TO THE ONSET OF PRECIP. CIGS ARE THEN EXPECTED TO BOUNCE AROUND BETWEEN FLT CATEGORIES UNTIL AROUND SUNRISE...WHEN STRONG LOW LEVEL LIFT DEVELOPS IN RESPONSE TO STRONG UPPER LEVEL STORM SYSTEM MOVING OUT OF THE LOWER MISS VALLEY. THIS SHOULD RESULT IN CIGS SETTLING TO THE IFR/LIFR RANGE...LASTING THROUGH THE DAY. PERIODS OF HEAVY RAIN ARE EXPECTED DURING THE DAYLIGHT HOURS...LIKELY RESULTING IN LONG DURATION OF IFR/LIFR VISBY. STRENGTHENING N/NE WINDS WILL DEVELOP AS LOW PRESSURE INTENSIFIES TO THE SOUTHWEST...WITH GUSTS IN THE 20S LIKELY BY AFTERNOON.THE OTHER ITEM OF CONCERN IS THAT RAIN WILL CHANGE TO SNOW AT KAVL BY 00Z. ACCUMULATING SNOWFALL IS LIKELY. THE UPSTATE TERMINALS MAY ALSO SEE SOME FLAKES AS WELL BEFORE THE PRECIP ENDS THURSDAY EVENING...BUT LITTLE OR NO ACCUMULATIONS IS EXPECTED. OUTLOOK...DRY HIGH PRESSURE WILL BEGIN BUILDING OVER THE REGION FRIDAY AND WILL REMAIN THROUGH THE WEEKEND. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT THE FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...FLOOD WATCH THROUGH THIS EVENING FOR GAZ010-017-018-026-028. WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT FOR GAZ010-017. NC...FLOOD WATCH THROUGH THIS EVENING FOR NCZ033-035-048>053-058- 059-062>065-501>510. WINTER STORM WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT FOR NCZ033-048>050-052-053-064-065-501>507-509. WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT FOR NCZ051-058-059-062-063. WINTER STORM WARNING FROM 7 AM THIS MORNING TO MIDNIGHT EST TONIGHT FOR NCZ051-058-059-062-063. WINTER STORM WATCH FROM THIS AFTERNOON THROUGH LATE TONIGHT FOR NCZ035>037-056-057-068>072-508-510. SC...FLOOD WATCH THROUGH THIS EVENING FOR SCZ001>007-010. WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT FOR SCZ001>003. && $$ SYNOPSIS...CSH NEAR TERM...NED/WIMBERLEY SHORT TERM...MCAVOY LONG TERM...HG AVIATION...JDL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
311 PM CST THU JAN 17 2013 .DISCUSSION.../ISSUED AT 311 PM CST/ WARM FRONT LIFTS NORTH TONIGHT GIVING WAY TO A MILD AND MOSTLY SUNNY FRIDAY ACROSS THE AREA. FORECAST TONIGHT A BIT TRICKY WITH POTENTIAL STRATUS ISSUES. MID LEVEL CLOUDS WILL CONTINUE TO STREAM ACROSS OUR NORTH THROUGH THE NIGHT ASSOCIATED WITH MID LEVEL FRONTAL BOUNDARY. HOWEVER THINK THE CWA WILL REMAIN DRY...OTHER THAN MAYBE AN ISOLATED FLURRY ACROSS SOUTHWEST MINNESOTA. AREA OF STRATUS FROM SOUTH OF SIOUX FALLS INTO EASTERN NEBRASKA CONTINUES TO DISSIPATE UNDER DAYTIME HEATING. HOWEVER...CURRENT THINKING...BACKED BY THE RAP AND NAM...IS THAT THIS AREA WILL REFORM AND EXPAND THIS EVENING INTO TONIGHT. WITH SOUTHERLY BOUNDARY LAYER FLOW THIS WILL THEN EXPAND AND COULD COVER MUCH OF THE CWA FOR A PERIOD TONIGHT. DRIER BOUNDARY LAYER MOVING IN FROM THE SOUTHWEST WILL ALLOW THE STRATUS TO CLEAR FROM SOUTHWEST TO NORTHEAST THROUGH THE NIGHT. COULD BE AREAS OF FOG AS WELL. BEST CHANCE OF STAYING CLEAR THROUGH THE NIGHT WILL BE WEST OF SIOUX CITY TO YANKTON UP TOWARDS GREGORY. LOW LEVEL JET INCREASES TONIGHT...WHICH SHOULD KEEP A SOUTHERLY BREEZE GOING. THE BREEZE COMBINED WITH POTENTIAL CLOUDS SHOULD KEEP LOWS ON THE WARM SIDE OF GUIDANCE. GENERALLY AROUND 20 SOUTHWEST MINNESOTA TO LOW AND MID 20S ELSEWHERE. LOWS WILL PROBABLY BE IN THE EVENING...WITH STEADY OR RISING TEMPERATURES OVERNIGHT. ANY STRATUS SHOULD EXIT THE CWA BY AROUND 12Z. COULD BE SOME CIRRUS OVERHEAD DURING THE DAY...BUT OVERALL EXPECTING A MOSTLY SUNNY DAY. KEPT HIGHS CLOSE TO THE ECMWF AND ECMWF MOS...AS THEY PERFORMED BEST ON WEDNESDAY. LOOKING AT LOW AND MID 40S NORTH TO THE LOW AND MID 50S CLOSER TO THE MISSOURI RIVER. WITH 925MB TEMPERATURES APPROACHING 10C IN OUR SOUTHWEST...WOULD NOT BE SURPRISED IF SOMEPLACE IN NORTH CENTRAL NEBRASKA...OR ADJACENT AREAS OF GREGORY AND CHARLES MIX COUNTIES COME CLOSE TO 60. /CHENARD MAJOR PATTERN CHANGE EXPECTED TO BEGIN ON SATURDAY AS AN ARCTIC BLAST DROPS SOUTHWARD INTO THE NORTHERN PLAINS. COLD FRONT SLATED TO PUSH THROUGH THE FORECAST AREA DURING THE DAY...AND THE BIG QUESTION IS HOW QUICKLY IT WILL ARRIVE. LARGE TEMPERATURE DISCREPANCIES BETWEEN MODELS FOR SATURDAY HIGHS WITH A STAGGERING NEARLY 30 DEGREE DIFFERENCE BETWEEN THE WARMEST AND COLDEST MODELS IN SIOUX FALLS. THE GFS AND NAM ARE THE FASTEST WITH PULLING THE COLDER AIR INTO THE FORECAST AREA WHILE THE ECMWF AND GEM PAINT A MUCH SLOWER PROGRESSION AND DEPICT A MILD DAY ACROSS THE CWA. HAVE OPTED FOR A MIDDLE GROUND SOLUTION WITH MIXING KEEPING TEMPERATURES ON THE MILDER SIDE. EXPECT THE MISSOURI VALLEY TO REACH NEAR 40 RANGING TO AROUND 30 AT OUR NORTHERN BORDER. FRONTAL PASSAGE IS EXPECTED TO BE DRY...BUT STRONG NORTHWEST WINDS IN ITS WAKE WILL PRODUCE SOME BRUTAL WIND CHILLS. WITH 925MB WINDS UP AROUND 50 KT AND STRONG COLD AIR ADVECTION...WOULD NOT BE SURPRISED TO SEE ADVISORY LEVEL WINDS. COLD AIR WILL QUICKLY DROP SOUTH LATE EVENING INTO THE OVERNIGHT AND LOWS SATURDAY NIGHT WILL BE IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. WINDS WILL DECREASE ON SUNDAY AS SURFACE HIGH PRESSURE QUICKLY SHUNTS SOUTHEAST OF THE REGION...BUT DO NOT EXPECT MUCH RECOVERY OF TEMPERATURES. HIGHS WILL ONLY BE IN THE SINGLE DIGITS AND TEENS FOR THE MAJORITY OF THE CWA. A QUICK SHOT OF LIGHT SNOW WILL MOVE SOUTHEAST DURING THE DAY AHEAD OF A REINFORCING SHOT OF COLD AIR. SNOW WOULD LIKELY BE BRIEF WITH NOT MUCH MOISTURE TO WORK WITH...HOWEVER THE COLD TEMPERATURES SHOULD PRODUCE UP TO AN INCH OF FLUFFY SNOW. NORTHERLY WINDS WILL PICK UP ONCE AGAIN BEHIND THE FRONT AND WOULD DRIFT WHATEVER SNOW FALLS ON SUNDAY. SUNDAY NIGHT WILL SEE SOME OF THE COLDEST TEMPERATURES OF THE SEASON SO FAR WITH THE NORTHERN HALF DROPPING INTO THE TEENS BELOW ZERO. FRIGID TEMPERATURES WILL CONTINUE INTO MONDAY WITH HIGHS NEAR ZERO IN OUR NORTHEAST. MODELS KEEP THE LARGE UPPER RIDGE OVER THE INTERMOUNTAIN WEST IN PLACE INTO TUESDAY...WHICH LEAVES THE FORECAST AREA UNDER COOL NORTHWEST FLOW. MODELS BRING A WEAK WAVE THROUGH THE FLOW AROUND THE MONDAY NIGHT TO TUESDAY TIME FRAME...HOWEVER NOT A LOT OF CONFIDENCE THAT THE CWA WILL SEE MUCH IMPACT. WILL LEAVE THE SLIGHT CHANCES THAT THE LATEST ALLBLEND PRODUCED FOR NOW. WARMER WEATHER MAY RETURN ON WEDNESDAY AND THURSDAY WITH THE RIDGE ADVANCING EASTWARD. && .AVIATION.../FOR THE 18Z TAF ISSUANCE/ CURRENTLY SEEING VFR STRATUS OVER MUCH OF THE FORECAST AREA. HOWEVER BAND OF IFR/LIFR STRATUS CONTINUES TO LINGER FROM YANKTON TO SIOUX CITY AND SOUTH INTO EASTERN NEBRASKA. WEAK BOUNDARY LAYER FLOW PREVENTING MUCH MOVEMENT...AND RAP SOUNDINGS SUGGEST DISSIPATION IS UNLIKELY. THUS NOW THINKING THAT KSUX STAYS STUCK IN THE IFR STRATUS THROUGH THE DAY AND INTO TONIGHT. WOULD NOT BE SURPRISED IF THE LIFR CIGS CURRENTLY WEST OF SIOUX CITY POSSIBLY MOVE IN TONIGHT...BUT WITH LOW CONFIDENCE ON TIMING AND CIG HEIGHT...WILL LEAVE THINGS IFR FOR NOW. AREA OF MVFR STRATUS OVER NORTH CENTRAL SOUTH DAKOTA IS BEGINNING TO MOVE BACK INTO OUR NORTHERN AREAS. RAP WOULD SUGGEST THIS MOVES INTO KHON AND KFSD FOR A PERIOD THIS AFTERNOON..BEFORE CLOUD LAYER FLOW TURNS SOUTHWESTERLY PUSHING IT BACK NORTH. WILL HAVE TO MONITOR THIS THOUGH...AS KFSD WILL LIKELY BE RIGHT ON THE EDGE OF THESE MVFR CIGS. OTHER CONCERN FOR KFSD IS THE IFR/LIFR STRATUS TO THE SOUTH MENTIONED ABOVE. BASED ON SATELLITE...BELIEVE THIS AREA IS NOT TOO FAR AWAY. AS BOUNDARY LAYER FLOW TURNS WEAK SOUTHERLY THINKING THIS MOVES IN LATER THIS AFTERNOON OR EVENING. THIS IS SHOWN BY THE RAP...WHICH EXPANDS THE CURRENT LOW STRATUS DECK NORTHWARD...EVENTUALLY POSSIBLY EVEN REACHING KHON. KEPT KFSD AND KHON AT LOW END MVFR FOR NOW...BUT THINKING A PERIOD OF IFR OR LIFR IS VERY POSSIBLE TONIGHT...ESPECIALLY AT KFSD. BY LATER TONIGHT...DRIER AIR WILL WORK IN FROM SOUTHWEST TO NORTHEAST...WITH ALL TAF SITES BECOMING VFR BY MORNING. /CHENARD && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1150 AM CST THU JAN 17 2013 .DISCUSSION.../ISSUED AT 955 AM CST/ A COUPLE AREAS OF CLOUDS ACROSS THE CWA AT THIS TIME...WITH A SMALL WINDOW OF CLEARING FROM SIOUX FALLS TO MARSHALL. THINK THIS AREA WILL GIVE WAY TO INCREASING CLOUDS...AS STRATUS IN CENTRAL SOUTH DAKOTA MOVES BACK IN. MEANWHILE...THERE IS A SECOND AREA OF LOWER CLOUDS CLOSER TO THE MISSOURI RIVER...FROM YANKTON TO SIOUX CITY AND SOUTH DOWN INTERSTATE 29 TOWARDS OMAHA AND LINCOLN NEBRASKA. WILL HAVE TO WATCH AND SEE WHAT HAPPENS WITH THIS THROUGH THE REST OF THE MORNING. RAP SUGGESTS IT MAY ACTUALLY EXPAND...AND WITH BOUNDARY LAYER FLOW BECOMING WEAK SOUTHWESTERLY...IT MAY LINGER ACROSS OUR NORTHWEST IOWA COUNTIES. AS FAR AS TEMPERATURES GO...WOULD NOT BE SURPRISED IF AREAS FROM WEST OF YANKTON TO GREGORY END UP A COUPLE DEGREES WARMER...ESPECIALLY IF IT REMAINS MOSTLY SUNNY. ALSO...AREAS FROM SIOUX FALLS TO SIOUX CITY AND EAST...MAY END UP A FEW DEGREES COOLER THAN CURRENT FORECAST IF CLOUDS HANG AROUND LIKE THE RAP IS SUGGESTING. GIVEN CLOUD COVER UNCERTAINTY...WILL LEAVE HIGHS ALONE FOR NOW AND ADJUST AS NEED BE AS CLOUD AND TEMPERATURE TRENDS BECOME MORE APPARENT LATER THIS MORNING. /CHENARD .PREVIOUS DISCUSSION.../ISSUED AT 305 AM CST/ A CHILLY START TO THE DAY AS A SHALLOW ARCTIC AIR MASS HAS STALLED OVER THE EASTERN HALF OF THE CWA. THIS WILL MODIFY THROUGH THE DAY LEADING TOWARDS HIGH TEMPERATURES A BIT ABOVE NORMAL...BUT NOT AS WARM AS YESTERDAY. CLOUDS AS WELL AS THE COOLER START WILL BE THE MAIN REASONS. REGARDLESS...PLANNING ON HIGHS FROM NEAR 40 ALONG THE MISSOURI RIVER TO THE MID 20S IN SOUTHWEST MINNESOTA. A STRONG SOUTHERLY PRESSURE GRADIENT WILL DEVELOP OVERNIGHT LEADING TOWARDS A NON DIURNAL TEMPERATURE PROFILE. LOWS IN MOST SPOTS WILL OCCUR BETWEEN ABOUT 2Z AND 6Z...THEN RISE AFTER. EXPECTING LOWS IN THE MID TEENS TO LOWER 20S BUT 12Z FRIDAY TEMPERATURES LIKELY TO BE BETWEEN 25 AND 30 DEGREES IN MOST LOCATIONS WITH A BIT OF A BREEZY SOUTH WIND. THIS WILL LEAD INTO A VERY WARM FRIDAY...ESPECIALLY LOOKING AT WHAT HAPPENED ACROSS THE AREA TODAY. NOT MUCH INT HE WAY OF CLOUD COVER AND WINDS TURNING FROM THE SOUTHWEST TO THE WEST AND NORTHWEST THROUGH THE DAY SUPPORTS MIXY AND MILD CONDITIONS. WITH 925MB TEMPERATURES WELL INTO THE SINGLE DIGITS...ESPECIALLY SOUTH...HIGHS SHOULD RANGE FROM THE LOWER 40S NORTH TO 50 TO 55 SOUTH. MILD WESTERLY FLOW WILL REMAIN IN PLACE THROUGH FRIDAY NIGHT INTO SATURDAY MORNING AHEAD OF A STRONG PUSH OF COLD AIR. TEMPERATURES SHOULD ONLY FALL INTO THE 20 TO 25 DEGREE RANGE FRIDAY NIGHT THEN QUICKLY WARM INTO THE MID 30S TO LOWER 40S ON SATURDAY AHEAD OF THE COLD FRONT. IF THE FRONT IS JUST A FEW HOURS SLOWER HIGHS WILL LIKELY BE ANOTHER 5 DEGREES WARMER SO TIMING OF THIS BOUNDARY WILL BE VERY IMPORTANT. HAVE TEMPERATURES TANKING LATE AFTERNOON AND EVENING AS THE FRONT BARRELS THROUGH. AT SOME POINT IN TIME MAY NEED A WIND ADVISORY FOR THE AREA AND POSSIBLY A WIND CHILL ADVISORY IN THE NORTHERN CWA. IN THE LATTER PERIODS(SUN/THU)...NOT MUCH IN THE WAY OF CHANGES AS BELOW NORMAL TEMPERATURES STILL THE MAIN ISSUE. A VERY STRONG RIDGE WILL BE IN PLACE OVER THE WESTERN UNITED STATES WHICH WILL ALLOW A NORTHERLY ORIENTED JET TO BE IN PLACE OVER THE NORTHERN PLAINS. THIS WILL MAKE IT DIFFICULT TO BREAK OUT OF THE COLD AIR DURING THE PERIOD. WILL CONTINUE THE CHANCE FOR SNOW ON SUNDAY AHEAD OF THE VERY STRONG COLD FRONT. NOT EXPECTING A LOT OF ACCUMULATION BUT MIGHT BE ENOUGH TO ADD A LITTLE TO WHAT IS OUT THERE. SUNDAY NIGHT INTO MONDAY EVENING LIKELY TO BE THE COLDEST 24 HOUR PERIOD THIS SEASON SO FAR WITH SOME TYPE OF COLD HEADLINE ANTICIPATED. AFTER THIS MODELS NOT REAL AGREEABLE BUT NOT TERRIBLE. LOOKS LIKE A SLOW MODERATING TREND THROUGH THE WEEK. /08 && .AVIATION.../FOR THE 18Z TAF ISSUANCE/ CURRENTLY SEEING VFR STRATUS OVER MUCH OF THE FORECAST AREA. HOWEVER BAND OF IFR/LIFR STRATUS CONTINUES TO LINGER FROM YANKTON TO SIOUX CITY AND SOUTH INTO EASTERN NEBRASKA. WEAK BOUNDARY LAYER FLOW PREVENTING MUCH MOVEMENT...AND RAP SOUNDINGS SUGGEST DISSIPATION IS UNLIKELY. THUS NOW THINKING THAT KSUX STAYS STUCK IN THE IFR STRATUS THROUGH THE DAY AND INTO TONIGHT. WOULD NOT BE SURPRISED IF THE LIFR CIGS CURRENTLY WEST OF SIOUX CITY POSSIBLY MOVE IN TONIGHT...BUT WITH LOW CONFIDENCE ON TIMING AND CIG HEIGHT...WILL LEAVE THINGS IFR FOR NOW. AREA OF MVFR STRATUS OVER NORTH CENTRAL SOUTH DAKOTA IS BEGINNING TO MOVE BACK INTO OUR NORTHERN AREAS. RAP WOULD SUGGEST THIS MOVES INTO KHON AND KFSD FOR A PERIOD THIS AFTERNOON..BEFORE CLOUD LAYER FLOW TURNS SOUTHWESTERLY PUSHING IT BACK NORTH. WILL HAVE TO MONITOR THIS THOUGH...AS KFSD WILL LIKELY BE RIGHT ON THE EDGE OF THESE MVFR CIGS. OTHER CONCERN FOR KFSD IS THE IFR/LIFR STRATUS TO THE SOUTH MENTIONED ABOVE. BASED ON SATELLITE...BELIEVE THIS AREA IS NOT TOO FAR AWAY. AS BOUNDARY LAYER FLOW TURNS WEAK SOUTHERLY THINKING THIS MOVES IN LATER THIS AFTERNOON OR EVENING. THIS IS SHOWN BY THE RAP...WHICH EXPANDS THE CURRENT LOW STRATUS DECK NORTHWARD...EVENTUALLY POSSIBLY EVEN REACHING KHON. KEPT KFSD AND KHON AT LOW END MVFR FOR NOW...BUT THINKING A PERIOD OF IFR OR LIFR IS VERY POSSIBLE TONIGHT...ESPECIALLY AT KFSD. BY LATER TONIGHT...DRIER AIR WILL WORK IN FROM SOUTHWEST TO NORTHEAST...WITH ALL TAF SITES BECOMING VFR BY MORNING. /CHENARD && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
955 AM CST THU JAN 17 2013 .DISCUSSION.../ISSUED AT 955 AM CST/ A COUPLE AREAS OF CLOUDS ACROSS THE CWA AT THIS TIME...WITH A SMALL WINDOW OF CLEARING FROM SIOUX FALLS TO MARSHALL. THINK THIS AREA WILL GIVE WAY TO INCREASING CLOUDS...AS STRATUS IN CENTRAL SOUTH DAKOTA MOVES BACK IN. MEANWHILE...THERE IS A SECOND AREA OF LOWER CLOUDS CLOSER TO THE MISSOURI RIVER...FROM YANKTON TO SIOUX CITY AND SOUTH DOWN INTERSTATE 29 TOWARDS OMAHA AND LINCOLN NEBRASKA. WILL HAVE TO WATCH AND SEE WHAT HAPPENS WITH THIS THROUGH THE REST OF THE MORNING. RAP SUGGESTS IT MAY ACTUALLY EXPAND...AND WITH BOUNDARY LAYER FLOW BECOMING WEAK SOUTHWESTERLY...IT MAY LINGER ACROSS OUR NORTHWEST IOWA COUNTIES. AS FAR AS TEMPERATURES GO...WOULD NOT BE SURPRISED IF AREAS FROM WEST OF YANKTON TO GREGORY END UP A COUPLE DEGREES WARMER...ESPECIALLY IF IT REMAINS MOSTLY SUNNY. ALSO...AREAS FROM SIOUX FALLS TO SIOUX CITY AND EAST...MAY END UP A FEW DEGREES COOLER THAN CURRENT FORECAST IF CLOUDS HANG AROUND LIKE THE RAP IS SUGGESTING. GIVEN CLOUD COVER UNCERTAINTY...WILL LEAVE HIGHS ALONE FOR NOW AND ADJUST AS NEED BE AS CLOUD AND TEMPERATURE TRENDS BECOME MORE APPARENT LATER THIS MORNING. /CHENARD .PREVIOUS DISCUSSION.../ISSUED AT 305 AM CST/ A CHILLY START TO THE DAY AS A SHALLOW ARCTIC AIR MASS HAS STALLED OVER THE EASTERN HALF OF THE CWA. THIS WILL MODIFY THROUGH THE DAY LEADING TOWARDS HIGH TEMPERATURES A BIT ABOVE NORMAL...BUT NOT AS WARM AS YESTERDAY. CLOUDS AS WELL AS THE COOLER START WILL BE THE MAIN REASONS. REGARDLESS...PLANNING ON HIGHS FROM NEAR 40 ALONG THE MISSOURI RIVER TO THE MID 20S IN SOUTHWEST MINNESOTA. A STRONG SOUTHERLY PRESSURE GRADIENT WILL DEVELOP OVERNIGHT LEADING TOWARDS A NON DIURNAL TEMPERATURE PROFILE. LOWS IN MOST SPOTS WILL OCCUR BETWEEN ABOUT 2Z AND 6Z...THEN RISE AFTER. EXPECTING LOWS IN THE MID TEENS TO LOWER 20S BUT 12Z FRIDAY TEMPERATURES LIKELY TO BE BETWEEN 25 AND 30 DEGREES IN MOST LOCATIONS WITH A BIT OF A BREEZY SOUTH WIND. THIS WILL LEAD INTO A VERY WARM FRIDAY...ESPECIALLY LOOKING AT WHAT HAPPENED ACROSS THE AREA TODAY. NOT MUCH INT HE WAY OF CLOUD COVER AND WINDS TURNING FROM THE SOUTHWEST TO THE WEST AND NORTHWEST THROUGH THE DAY SUPPORTS MIXY AND MILD CONDITIONS. WITH 925MB TEMPERATURES WELL INTO THE SINGLE DIGITS...ESPECIALLY SOUTH...HIGHS SHOULD RANGE FROM THE LOWER 40S NORTH TO 50 TO 55 SOUTH. MILD WESTERLY FLOW WILL REMAIN IN PLACE THROUGH FRIDAY NIGHT INTO SATURDAY MORNING AHEAD OF A STRONG PUSH OF COLD AIR. TEMPERATURES SHOULD ONLY FALL INTO THE 20 TO 25 DEGREE RANGE FRIDAY NIGHT THEN QUICKLY WARM INTO THE MID 30S TO LOWER 40S ON SATURDAY AHEAD OF THE COLD FRONT. IF THE FRONT IS JUST A FEW HOURS SLOWER HIGHS WILL LIKELY BE ANOTHER 5 DEGREES WARMER SO TIMING OF THIS BOUNDARY WILL BE VERY IMPORTANT. HAVE TEMPERATURES TANKING LATE AFTERNOON AND EVENING AS THE FRONT BARRELS THROUGH. AT SOME POINT IN TIME MAY NEED A WIND ADVISORY FOR THE AREA AND POSSIBLY A WIND CHILL ADVISORY IN THE NORTHERN CWA. IN THE LATTER PERIODS(SUN/THU)...NOT MUCH IN THE WAY OF CHANGES AS BELOW NORMAL TEMPERATURES STILL THE MAIN ISSUE. A VERY STRONG RIDGE WILL BE IN PLACE OVER THE WESTERN UNITED STATES WHICH WILL ALLOW A NORTHERLY ORIENTED JET TO BE IN PLACE OVER THE NORTHERN PLAINS. THIS WILL MAKE IT DIFFICULT TO BREAK OUT OF THE COLD AIR DURING THE PERIOD. WILL CONTINUE THE CHANCE FOR SNOW ON SUNDAY AHEAD OF THE VERY STRONG COLD FRONT. NOT EXPECTING A LOT OF ACCUMULATION BUT MIGHT BE ENOUGH TO ADD A LITTLE TO WHAT IS OUT THERE. SUNDAY NIGHT INTO MONDAY EVENING LIKELY TO BE THE COLDEST 24 HOUR PERIOD THIS SEASON SO FAR WITH SOME TYPE OF COLD HEADLINE ANTICIPATED. AFTER THIS MODELS NOT REAL AGREEABLE BUT NOT TERRIBLE. LOOKS LIKE A SLOW MODERATING TREND THROUGH THE WEEK. /08 && .AVIATION.../FOR THE 12Z TAF ISSUANCE/ APPEARS TO BE MANY CLOUD LAYERS AT VARYING HEIGHTS ACROSS THE REGION AT THE START OF THE PERIOD. PRIMARY TO AVIATION CONCERNS IS IFR-LIFR BAND OF STRATUS WITHIN SURFACE RIDGE AXIS FROM THE LOWER JAMES RIVER VALLEY INTO NORTHEAST NEBRASKA. DIFFICULT TO DISCERN THIS BAND FROM PRIMARILY VFR STRATUS FARTHER TO THE EAST...HOWEVER NAM/RAP MODELS DO SHOW THIS VERY LOW LEVEL MOISTURE BAND MOVING TOWARD THE KSUX TAF SITE BY MID-LATE MORNING. CONFIDENCE IS LOW THAT THE BAND WILL HOLD TOGETHER/REACH KSUX...SO JUST WENT WITH MENTION OF SCATTERED CLOUD LAYER BELOW 1KFT FOR NOW...BUT WILL WATCH CLOSELY THROUGH THE EARLY PART OF THE PERIOD TO SEE IF BAND HOLDS TOGETHER. SOME MVFR STRATUS CEILINGS SLIDING THROUGH NORTHEAST PARTS OF THE FORECAST AREA AS WELL THIS MORNING...BUT NOT EXPECTED TO AFFECT TAF SITES AT THIS TIME. BY 18Z...VFR CONDITIONS EXPECTED TO DOMINATE ACROSS THE AREA WITH LIGHT/VARIABLE WINDS. NAM/RAP MODELS HINTING AT IFR-LIFR STRATUS AND/OR FOG REDEVELOPING OVERNIGHT...POTENTIALLY AFFECTING KFSD/KSUX AFTER 04Z IN ADVANCE OF SURFACE WARM FRONT. AGAIN HAVE LOW CONFIDENCE IN THIS DEVELOPMENT AS MOISTURE LAYER APPEARS TO BE SHALLOW ON FORECAST SOUNDINGS...SO HAVE LEFT TAFS VFR THROUGH THE NIGHT FOR NOW. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1117 PM CST WED JAN 16 2013 .UPDATE...FOR 06Z AVIATION FORECAST && .AVIATION... WINTER STORM WATCH IN EFFECT FOR THE PLATEAU ON THURSDAY AS FREEZING RAIN...SLEET AND SNOW WILL LIKELY IMPACT THE AREA. THEREFORE POOR FLYING CONDITIONS WILL EXITS ALONG THE PLATEAU BEGINNING AROUND 08Z AS CEILINGS AND VSBYS LOWER AND A MIX OF LIGHT RAIN AND SLEET BEGINS. WINTER WEATHER WILL CONTINUE ALONG THE PLATEAU DURING THE OVERNIGHT HOUR AND DURING THE DAY ON THURSDAY. AS FOR NASHVILLE NOT EXPECTING SIGNIFICANT PRECIP BUT WE COULD SEE A MIX OF LIGHT RAIN AND SNOW FROM ABOUT MID MORNING THROUGH NOON AND THEN A FEW FLURRIES IN THE AFTERNOON. MVFR CONDITIONS DUE TO CEILINGS AND VSBYS WILL PREVAIL THROUGH A GOOD PART OF THE NEXT 24 HOURS. CLARKSVILLE WILL LIKELY REMAIN VFR THROUGH A GOOD PART OF THE NEXT 24 HOURS WITH MVFR CONDITIONS POSSIBLE DUE TO CEILINGS FROM 15Z TO ABOUT 18Z ON THURSDAY. FLURRIES ARE POSSIBLE IN THE AFTERNOON ON THURSDAY. GUSTY WINDS CAN BE EXPECTED ACROSS THE MID STATE FROM ABOUT MID- DAY ON THROUGH THE AFTERNOON WITH SOME GUSTS OVER 20 KNOTS. UPPER LOW OVER TEXARKANA WILL MOVE EASTWARD IN THE OVERNIGHT. 850 MILLIBAR LOW ABOUT JACKSON MISSISSIPPI. GOOD UPPER DIFFLUENCE ACROSS THE TENNESSEE VALLEY WILL INCREASE IN THE OVERNIGHT AND ON THURSDAY. LATEST RUC RUN HAS PRECIP BREAKING OUT SOUTHERN AND EASTERN AREAS OF THE MID STATE AND ALONG THE PLATEAU. THIS IN LINE WITH LATEST NSSL WRF RUN. BOYD && .PREV DISCUSSION... /ISSUED 946 PM CST WED JAN 16 2013/ UPDATE... LATEST RADAR IMAGERY SHOWS RAIN HAS DIMINISHED IN COVERAGE AND INTENSITY THIS EVENING WITH ONE MAIN BAND NOW EXTENDING FROM NORTHWEST ALABAMA TO THE NORTHERN PLATEAU. HOWEVER...WATER VAPOR IMAGERY DEPICTS A STRONG UPPER LEVEL LOW OVER EASTERN TEXAS THAT WILL BE MOVING EASTWARD ACROSS THE GULF COAST STATES TO OUR SOUTH TOMORROW. RAIN HAS ALREADY BEGUN DEVELOPING AND EXPANDING IN COVERAGE ACROSS LOUISIANA AND MISSISSIPPI IN ASSOCIATION WITH THIS SYSTEM...AND ADDITIONAL RAINFALL IS EXPECTED TO FORM LATE TONIGHT AND SPREAD NORTHEASTWARD INTO OUR EASTERN ZONES. THERMAL PROFILES WILL REMAIN TOO WARM FOR ANYTHING BUT RAIN TONIGHT EXCEPT POSSIBLY ON THE FAR NORTHWEST EDGE OF THE PRECIPITATION WHERE A VERY LIGHT RAIN/SNOW MIX HAS BEEN LEFT IN. HAVE UPDATED TEMPS AND POPS FOR TONIGHT BASED ON THESE LATEST TRENDS. AS UPPER LEVEL LOW MOVES TO OUR SOUTH DURING THE DAY ON THURSDAY...A SURFACE LOW IS EXPECTED TO TAKE SHAPE AND DEEPEN OVER THE CAROLINAS. CAA WILL CORRESPONDINGLY INCREASE ACROSS THE MID STATE DURING THE DAY WITH GUSTY NORTH WINDS EXPECTED. AN EXTENSIVE LOOK AT BUFKIT SOUNDINGS INDICATES THERMAL PROFILES WILL BECOME FAVORABLE FOR A MIX OF RAIN AND SNOW...AND POSSIBLY FREEZING RAIN AS WELL...OVER OUR PLATEAU COUNTIES THURSDAY MORNING AS COLD AIR CONTINUES TO ADVECT SOUTHWARD...WITH A CHANGEOVER TO ALL SNOW BY AFTERNOON AS SATURATED PROFILES FALL COMPLETELY BELOW FREEZING. ALL PRECIP THEN EXITS THE AREA QUICKLY BY THURSDAY EVENING AS SYSTEM SHIFTS OFF TO THE EAST. SOME UNCERTAINTY REMAINS ON SNOW ACCUMS IN THE WSW AREA WITH BULK OF PRECIP REMAINING TO OUR EAST AND CONCERNS WITH TIMING OF CHANGEOVER AND SNOWFALL RATES. CURRENT REASONING IS CLOSEST TO A BLEND OF HPC GUIDANCE WITH NAM/GFS SNOW ACCUMS...AND SHOWING A GENERAL 1 TO 3 INCHES OF TOTAL SNOWFALL POSSIBLE ON THE PLATEAU...WITH 4 INCH AMOUNTS NOT OUT OF THE QUESTION IN THE TYPICALLY FAVORED AREAS OF HIGHER TERRAIN IN EASTERN PUTNAM/CUMBERLAND/FENTRESS COUNTIES. SUCH AMOUNTS WOULD GENERALLY BE A WINTER WEATHER ADVISORY TYPE EVENT...BUT WILL LET MID SHIFT TAKE A LOOK AT 00Z GUIDANCE BEFORE DECIDING WHETHER AN ADVISORY OR WARNING IS WARRANTED. ALSO APPEARS THERE WILL BE A SHARP CUTOFF TO PRECIPITATION ON NORTHWEST EDGE OF PRECIP SHIELD PER 00Z NAM AND MUCH OF MIDDLE TENNESSEE WEST OF THE CURRENT WSW AREA MAY BE TOTALLY DRY TOMORROW...BUT WILL LEAVE LOW POPS IN FOR NOW. UPDATED PRODUCTS WILL BE OUT SHORTLY. PREV DISCUSSION... /ISSUED 649 PM CST WED JAN 16 2013/ UPDATE...FOR CSV AMENDMENT AT 170043Z AVIATION... TAKING A CLOSER LOOK AT THE FORECAST SOUNDING FOR CROSSVILLE HAVE AMENDED TO INCLUDE A PERIOD OF FREEZING RAIN AND SLEET FROM 17/14Z THROUGH ABOUT 17/18Z WITH SNOW BEGINNING BY 17/20Z. ICE ACCUMULATIONS ARE LIKELY ALONG THE PLATEAU ON THURSDAY WITH SNOW ACCUMULATIONS OF 2 TO 4 INCHES POSSIBLE THURSDAY AFTERNOON. BOYD PREV DISCUSSION... /ISSUED 603 PM CST WED JAN 16 2013/ UPDATE...FOR 00Z AVIATION FORECAST AVIATION... CLOSED OFF UPPER LOW OVER NORTHEAST TEXAS THIS EVENING WILL SWING EAST TONIGHT AND INTO MISSISSIPPI BY DAYBREAK THURSDAY. UPPER LOW WILL MOVE EAST ACROSS ALABAMA AND INTO NORTHEAST GEORGIA BY EARLY THURSDAY EVENING. MID STATE WILL BE ON THE COLD SIDE OF THIS SYSTEM WITH GOOD COLD ADVECTION SPILLING IN DURING THE LATE MORNING AND MID DAY ON THURSDAY. MORE RAIN TONIGHT AND THURSDAY MORNING ACROSS SOUTHERN AND EASTERN AREAS WILL CHANGE TO SNOW OVER EASTERN AREAS AND ALONG THE PLATEAU AROUND MID DAY THURSDAY WITH ACCUMULATIONS LIKELY. THE SNOW COULD BECOME HEAVY AT TIMES AT CROSSVILLE WITH VERTICAL VISIBILITIES OF < 100 FEET AND HORIZONTAL VISIBILITIES DOWN TO 1/4 SM WITH SNOW ACCUMULATIONS LIKELY. SNOW WILL CONTINUE INTO THE EVENING ALONG THE PLATEAU. BOYD PREV DISCUSSION... /ISSUED 354 PM CST WED JAN 16 2013/ DISCUSSION...LIGHT RAIN CONTINUES TO TRICKLE ACROSS MAINLY SOUTHERN AND EASTERN MIDDLE TENNESSEE, WITH THE COLDEST PARTS OF THE MID STATE STILL ECHO-FREE. LOOK FOR PRECIPITATION TO GRADUALLY INCREASE OVERNIGHT AND TOMORROW AS AN UPPER LOW, CURRENTLY LOCATED OVER THE ARK-LA-TEX, MOVES EASTWARD OVER THE NEXT 24 HOURS AND SPREADS ADDITIONAL MOISTURE OVER MIDDLE TENNESSEE. WITH THE MID STATE REMAINING ON THE COLD SIDE OF THE LOW, TEMPERATURES AREN`T GOING TO WARM A GREAT DEAL. AREAS TO BE AFFECTED BY THIS SYSTEM ARE PRIMARILY THE AREAS BEING AFFECTED NOW, THAT BEING SOUTHERN MIDDLE TENNESSEE AND AREAS ALONG AND JUST WEST OF THE CUMBERLAND PLATEAU. PRECIPITATION WILL REMAIN LIQUID DURING THE EVENING, BUT LIGHT SNOW MAY MIX IN OVERNIGHT ACROSS THE COLDER PARTS, INCLUDING THE NASHVILLE METRO AREA. LIGHT ACCUMULATIONS MAY OCCUR AS TEMPERATURES BRIEFLY DROP TO FREEZING, BUT POP`S IN THESE AREAS ARE LOW AND QPF`S REMAIN LOW, SO VERY LITTLE FROZEN PRECIPITATION WILL OCCUR. LOOK FOR THE RAIN/SNOW MIX TO SPREAD EASTWARD DURING THE MORNING AS ABOVE-SURFACE TEMPERATURES ALONG THE PLATEAU COOL. (THICKNESS VALUES BY THURSDAY AFTERNOON DO SUPPORT SNOW.) SURFACE TEMPERATURES WILL REMAIN ABOVE FREEZING THROUGHOUT MOST OF THE DAY, WITH TEMPERATURES GETTING INTO THE LOWER 40`S TOMORROW AFTERNOON ACROSS MAINLY THE WESTERN HALF OF MIDDLE TENNESSEE. PLATEAU LOCATIONS WILL LIKELY SEE LIGHT ACCUMULATION OF SNOW THURSDAY AFTERNOON AND EARLY EVENING, WITH AMOUNTS GENERALLY UNDER ONE-HALF INCH. THIS WILL KEEP US BELOW ADVISORY CRITERIA, SO WILL COVER THIS WITH A SPECIAL WEATHER STATEMENT SHORTLY. && .OHX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM 6 AM CST THURSDAY THROUGH THURSDAY AFTERNOON FOR TNZ011-032>034-065-066-077>080. && $$ 01
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
243 AM MST SAT JAN 19 2013 .SHORT TERM...DRY NW FLOW ALOFT WILL CONTINUE TODAY AND TONIGHT. A MTN WAVE EARLY THIS MORNING IS ALLOWING FOR SOME GUSTY NWLY WINDS IN AND NR THE FOOTHILLS WHICH WILL LINGER THRU THE MID MORNING HOURS BEFORE DECREASING SOME BY MIDDAY. OTHERWISE GUSTY NW WINDS WILL ALSO OCCUR ALONG AND NR THE WY-NE BORDER ESPECIALLY LATER THIS MORNING INTO THE AFTN HOURS AS BETTER MIXING DEVELOPS. AS FOR HIGHS READINGS WILL BE IN THE 50S ACROSS NERN CO. ONCE AGAIN IN THE HIGHER MTN VALLEYS INVERSIONS WILL LEAD TO WIDE TEMP SPREADS ESPECIALLY ACROSS ZONE 32. FOR TONIGHT ANOTHER MTN WAVE MAY DEVELOP AFTER MIDNIGHT LEADING TO AN INCREASE IN WINDS OVER THE HIGHER MTNS AND FOOTHILLS. AT THIS TIME IT APPEARS SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA. .LONG TERM...NORTHWESTERLY FLOW ALOFT IS PROGGED TO CONTINUE OVER THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. ON MONDAY...THE FLOW IS PROGGED TO BECOME NORTH-NORTHWESTERLY AND INCREASE A BIT IN SPEED. BY TUESDAY MORNING AT 12Z IT WEAKENS AND IS BACK TO A NORTHWESTERLY DIRECTION. AT THAT TIME AN UPPER RIDGE AXIS IS LOCATED OVER THE GREAT BASIN. THE SYNOPTIC SCALE ENERGY IS PROGGED TO BE BENIGN SUNDAY THROUGH MONDAY NIGHT. THE BOUNDARY LAYER FLOW LOOKS TO BE UPSLOPING FOR THE PLAINS AND FOOTHILLS SUNDAY...WITH NORMAL DUIRNAL PATTERNS FOR SUNDAY NIGHT INTO MONDAY. LOW LEVEL TROUHGING EAST OF THE MOUNTAINS SETS UP LATER SUNDAY THROUGH TUESDAY NIGHT...BUT THE GRADIENT IS PRETTY WEAK. A MIX OF NORMAL TRENDS TO DOWNSLOPING SHOULD PREVAIL THOSE TWO PERIODS. MOISTURE CONTINUES TO BE QUITE LIMITED ACCORDING TO THE MODELS. THERE IS A LITTLE OVER THE PLAINS WITH THE UPSLOPE SUNDAY AFTERNOON AND EVENING...MORE SO ON THE GFS. THE GFS ALSO SHOWS A TAD IN THE UPPER LEVELS MONDAY AND MONDAY NIGHT...BUT THAT`S ABOUT IT. THERE IS NO MEASURABLE PRECIPITATION NOTED ON THE QPF FIELDS FOR THE FORECAST AREA SUNDAY THROUGH MONDAY NIGHT. NO POPS. FOR TEMPERATURES...SUNDAY`S HIGHS ARE 4-8 C COLDER THAN TODAY`S EXPECTED HIGHS. MONDAY`S READINGS WARM UP 3-5 C OVER SUNDAY`S. FOR THE LATER DAYS...TUESDAY THROUGH FRIDAY...MODELS HAVE PRETTY WEAK NORTHWESTERLY FLOW ALOFT FOR THE CWA TUESDAY AND WEDNESDAY. BY THURSDAY...THE ECMWF AND GFS START DEVELOPING AN UPPER TROUGH NORTH AND NORTHEAST OF COLORADO. THE FLOW ALOFT INCREASES AND IS ZONAL ON THURSDAY. BY FRIDAY...A MEAN TROUGH IS PROGGED TO COVER THE EASTERN HALF OF NORTH AMERICA...AND AN UPPER RIDGE IS OVER THE GREAT BASIN. THE GFS BRINGS SOME MOISTURE OVER THE CWA THURSDAY AND THURSDAY NIGHT. THE ECMWF DOES NOT. THE OTHER DAYS ARE PRETTY DRY ON BOTH MODELS. WILL KEEP POPS OUT FOR NOW. TEMPERATURES REMAIN ABOVE SEASONAL NORMALS THROUGH THE PERIOD. && .AVIATION...WEST WINDS HAVE SPREAD ACROSS THE AIRPORT EARLY THIS MORNING BUT SHOULD BECOME MORE SWLY AFTER SUNRISE. BY 16Z WINDS MAY BECOME MORE SLY. FOR THIS AFTN THERE IS QUITE A DIFFERENCE IN WIND FCSTS AS THE HRRR AND RAP INDICATE A LONGMONT ANTI-CYCLONE DEVELOPING WITH WINDS BECOMING MORE ELY BY EARLY AFTN WHILE THE NAM HAS A WLY COMPONENT. WITH NWLY FLOW OVER THE CHEYENNE RIDGE THAT WOULD FAVOR A POTENTIAL ANTI-CYCLONE SO WILL TREND TAF TOWARDS THE HRRR/RAP SOLUTION. BY EARLY EVENING WINDS SHOULD GRADUALLY TRENDS TOWARDS DRAINAGE. VFR CONDITIONS WILL BE IN PLACE TODAY THRU TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM....RJK AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
352 AM EST SAT JAN 19 2013 .DISCUSSION... CURRENTLY...STRONG HI PRES RIDGE EXTENDING FROM THE CAROLINAS TO THE NW GOMEX. THE USAF CAPE PROFILER AND THE KTBW VAD WIND PROFILE SHOWING 25-30KTS OF ERLY FLOW 5KFT...DIMINISHING TO 15-25KTS AT THE KJAX VAD WIND PROFILE. RAP ANALYSIS SHOWS HIGH REGIONAL MOISTURE THRU THE H100-H85 LYR ASSOCD WITH A MARINE STRATOCU DECK. KMFL/KTBW EVENING SOUNDINGS HAVE A SATURATED H100-H80 LYR TRAPPED BLO A STOUT SUBSIDENCE INVERSION...THOUGH PWAT VALUES TOP OUT ARND 0.80". KJAX SOUNDING IS A BIT DRIER WITH PWAT ARND 0.40". RADAR SHOWS PERIODIC BANDS OF LIGHT RAIN MVG ONSHORE S OF CAPE CANAVERAL. TODAY-TONIGHT...THE HI PRES RIDGE WILL MAINTAIN A DEEP/STEADY NERLY SFC/LOW LVL FLOW AS IT GRADUALLY WEAKENS. LOW LVL MOISTURE IS HIGH ENOUGH TO MAINTAIN ISOLD/SCT SHRAS...THOUGH ITS SHALLOW DEPTH WILL LIMIT QPF TO 0.10" OR LESS. DEPTH/STRENGTH OF THE NE FLOW WILL PUSH THESE SHRAS WELL INTO THE INTERIOR THRU THE AFTN. PRECIP WILL END OVER THE INTERIOR OVERNIGHT AS WINDS DIMINISH BUT WILL CONTINUE ALONG THE COAST. THE DEEP ONSHORE FLOW WILL TAP MOIST/MILD OCEAN AIR TO KEEP TEMPS ABV AVG. MAXES IN THE M/U70S...MINS IN THE M/U50S ALONG AND N OF THE I-4 CORRIDOR AND L/M60S ALONG THE SPACE/TREASURE COASTS. SUN...A WEAK INVERTED TROUGH IS FORECAST TO DEVELOP EAST OF FLORIDA WHICH WILL BACK THE LOW LEVEL FLOW SOME...TO THE N/NE. IT WILL ALSO PRODUCE A BAND OF MOISTURE CONVERGENCE EXTENDING FROM THE ATLC SW ACROSS THE COAST TOWARDS OKEECHOBEE...WHICH SHOULD PRODUCE BRING SOME SHOWERS ACROSS THE COAST MAINLY SOUTH OF THE CAPE. SO WILL MAINTAIN A SMALL 20 POP THERE AS WELL AS SOUTHERN INTERIOR SECTIONS THOUGH SOME AREAS COULD SEE A FEW PERIODS OF RAIN WITH LOCALLY HIGHER RAIN CHANCES AND AMOUNTS. FORECAST MODEL SOUNDINGS SHOW CONSIDERABLE STRATOCUMULUS CLOUDS ALONG WITH SOME CIRRUS SO MORE CLOUDS THAN SUN EXPECTED. NONETHELESS... TEMPERATURES WILL REMAIN SLIGHTLY ABOVE NORMAL WITH HIGHS IN THE MID 70S. LESS ONSHORE FLOW SUNDAY NIGHT SHOULD ALLOW COASTAL COMMUNITIES SOUTH OF THE CAPE TO COOL A FEW MORE DEGREES WITH LOWS NEAR 60. MON-FRI...THE WEEK BEGINS WITH A HIGHLY AMPLIFIED UPPER PATTERN ACROSS THE U.S...RIDGE IN THE WEST AND TROUGH IN THE EAST. MEANWHILE...AT THE SURFACE A REINFORCING HI PRES RIDGE WILL DROP OUT OF CANADA AND BUILD INTO THE SE U.S. MONDAY AND TUESDAY AND BRING COOLER AND ESPECIALLY DRIER CONDITIONS INTO MIDWEEK. PRIOR TO INFLUX OF MUCH DRIER AIR...THERE STILL LOOKS TO BE ENOUGH MOISTURE TO PRODUCE A FEW SHOWERS MONDAY ALG THE TREASURE COAST TO OKEECHOBEE SO HAVE MAINTAINED SMALL 20 POP THERE. RAIN CHANCES LOOK QUITE SLIM TUE-THU AND HAVE KEPT THE FORECAST DRY. AFTER A MILD MONDAY...BOTH HIGH AND LOW TEMPERATURES ARE FORECAST TO FALL AT OR SLIGHTLY BELOW NORMAL TUE-WED WITH UPPER 30S POSSIBLE ACROSS NORTH LAKE COUNTY WED MORNING. FREEZING TEMPERATURES ARE STILL NOT EXPECTED AT THIS TIME. HIGH TEMPS ARE FORECAST TO RANGE FROM THE MID 60S NORTH OF ORLANDO TO THE LOWER 70S OKEECHOBEE/ TREASURE COAST. SOME MODERATION OF TEMP/MOISTURE WILL OCCUR BY THU AS HIGH PRESSURE PUSHES EAST INTO THE ATLC AND A MORE DIRECT ONSHORE FLOW DEVELOPS. && .AVIATION... THRU 20/00Z...PREVAILING CIGS BTWN FL040-060. ISOLD MVFR SHRAS E OF KTIX-KISM-KOBE THRU 19/14Z. AFT 19/14Z...ISOLD MVFR SHRAS ALL SITES WITH SFC WND G18-22KTS. && .MARINE... TODAY-TONIGHT...RIDGE AXIS OVER THE DEEP SOUTH WILL MAINTAIN A MODERATE TO FRESH NERLY BREEZE THRU MID AFTN. THE RIDGE WILL GRADUALLY WEAKEN THRU DAYBREAK SUN...ALLOWING WIND TO DIMINISH BLO THE 20KT SCA THRESHOLD BY LATE AFTN. HOWEVER...THE NE COMPONENT WILL CONTINUE TO PUSH SWELL ENERGY INTO THE E FL COAST...KEEPING SEAS ABV SCA CRITERIA THRU EARLY SUN MORNING. WIND SCA EXPIRATION TIME OF 21Z LOOKS REASONABLE...WILL EXTEND THE SCA FOR SEAS THRU 09Z SUN. SUN-WED...INVERTED TROUGH DEVELOPING EAST OF THE WATERS WILL BACK WINDS TO A MORE N/NE DIRECTION SUNDAY WITH SPEEDS AROUND 10-15 KTS AND SEAS 4-6 FT. SO WILL LIKELY NEED A CAUTION HEADLINE AT LEAST FOR THE GULF STREAM SUNDAY. WATERS WILL BE IN A LIGHT NORTHERLY PRES GRAD MONDAY BUT NORTH WINDS WILL INCREASE MONDAY NIGHT/EARLY TUE AS HIGH PRESSURE BUILDS OVER THE AREA FROM THE NORTHWEST. THERE WILL LIKELY BE A BRIEF PERIOD OF HAZARDOUS BOATING CONDITIONS WITH ADVISORIES ISSUED TUE/TUE NIGHT. SWAN MODEL BUILDS SEAS TO 6 FT OFFSHORE WOULD NOT BE SURPRISED TO SEE 7 FT IN THE GULF STREAM. THEN WINDS DECREASE PRETTY QUICKLY WED AS HIGH PRESSURE CENTER SETTLES OVER THE AREA WITH SEAS SUBSIDING. && .FIRE WEATHER... NO LOW RH CONCERNS THROUGH MONDAY THOUGH MIN RH VALUES WILL BE A LITTLE LOWER...40 TO 45 PERCENT ORLANDO NORTHWARD...MONDAY AFTN. COOLER AND MUCH DRIER AIR IS FORECAST TO OVERSPREAD THE AREA TUE AND PRODUCE MIN RH VALUES BELOW 35 PERCENT WITH N/NW WINDS AROUND 15 MPH. WED COULD BE NEARLY AS DRY ACROSS THE INTERIOR BUT WINDS LOOK LIGHTER. && .PRELIMINARY POINT TEMPS/POPS... DAB 74 60 73 55 / 20 10 10 10 MCO 76 59 76 57 / 20 10 10 10 MLB 75 65 77 61 / 30 20 20 20 VRB 75 65 78 60 / 30 20 20 20 LEE 75 57 75 55 / 20 10 10 10 SFB 75 59 75 57 / 20 10 10 10 ORL 75 59 75 58 / 20 10 10 10 FPR 76 65 77 61 / 30 20 20 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE OUT 20 NM-COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM-WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE- WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 4 PM THIS AFTERNOON TO 4 AM EST SUNDAY FOR COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE OUT 20 NM-COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM-WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE. && $$ SHORT TERM...BRAGAW LONG TERM....KELLY
AREA FORECAST DISCUSSION
NWS MIAMI FL
809 AM EST SAT JAN 19 2013 .UPDATE...UPDATED MOST ELEMENTS FOR CURRENT TRENDS. AREA OF LIGHT RAIN NOW IS FOCUSED ACROSS METRO BROWARD. HRRR AND NAM SHOW A GRADUALLY NORTHWARD SHIFT ALONG THE ATLANTIC COAST WITH TIME TODAY. NAM KEEPS A SOLID AREA OF QPF MOVING UP THE PALM BEACH COAST WHILE THE HRRR LESSENS QPF THIS AFTERNOON, SO TOOK A MIDDLE OF THE ROAD APPROACH. LOOKS LIKE TWO WEAK LOWS HAVE DEVELOPED...ONE OVER OUR ATLANTIC WATERS AND ANOTHER CLEARLY DEFINED ONE ON SAT IMAGERY OVER THE GULF OFF THE SW FL COAST. THESE FEATURES WILL KEEP EXTENSIVE CLOUDINESS OVER THE AREA TODAY, BUT WITH A FEW BREAKS EXPECTED IN THE AFTERNOON. THIS SHOULD MANAGE TO ALLOW TEMPS TO REACH FORECASTED HIGHS, BUT WILL NEED TO MONITOR THIS BC IF THERE ARE NO BREAKS, HIGHS MAY BE A TAD TOO WARM. IT DOESN`T TAKE MUCH BREAKS TO ACHIEVE OUR WARMER HIGHS ADVERTISED SO HAVE KEPT THE FCST AS IS FOR NOW FOR MAX T. /GREGORIA && .PREV DISCUSSION... /ISSUED 645 AM EST SAT JAN 19 2013/ AVIATION... MOSTLY CLOUDY SKIES WILL PREVAIL ACROSS SOUTH FLORIDA THIS MORNING. LIGHT DRAINAGE FLOW IS STILL PRESENT ACROSS THE EASTERN TERMINALS...BUT WILL SHIFT TO THE EAST BY 19/18Z. VCSH WAS KEPT AS PREVAILING AT ALL EASTERN TERMINALS EXCEPT FOR KPBI. SHOWERS WILL CONTINUE DEVELOPING THIS AFTERNOON...FOR THIS REASON KEPT VCSH AT ALL EASTERN TERMINALS THROUGH THE EVENING. FOR KAPF...DRY CONDITIONS EXPECTED THROUGH THE PERIOD. WIND FLOW WILL BE WEAK ENOUGH TO ALLOW FOR THE SEABREEZE TO DEVELOP BY 19/19Z. PREV DISCUSSION... /ISSUED 338 AM EST SAT JAN 19 2013/ DISCUSSION... AN ACTIVE NIGHT ALONG THE ATLANTIC COAST HAS BEEN THE CASE THIS MORNING. SHOWERS HAVE BEEN DEVELOPING ALL NIGHT ALONG A STALLED FRONTAL BOUNDARY, LAYING JUST TO THE SOUTHEAST OF THE CWA. MODELS ARE SHOWING A WEAK LOW FORMING ALONG THIS BOUNDARY, WHICH WILL ACT AS THE FOCAL POINT FOR CONTINUED DEVELOPMENT OF SHOWERS TODAY, MAINLY SCATTERED IN NATURE. THIS ACTIVITY WILL CONTINUE INTO THE EVENING HOURS AND BEGIN TO DIE DOWN TONIGHT. THE LOW THEN LOOKS TO FALL APART LATER ON SUNDAY. THERE LOOKS TO BE SOME UPPER LEVEL SUPPORT FOR THE SHOWERS TO BE NORTH, AS A JET STREAK WILL MOVE IN AND THE LEFT EXIT REGION WILL BE AROUND THE JAX AREA. KEPT A MENTION OF MAINLY A SLIGHT CHANCE OF COASTAL SHOWERS FOR THE NEXT FEW DAYS. FOR THE BEGINNING OF THE WEEK, A COLD FRONT, WITH AN ARCTIC PUSH, MOVES THROUGH THE CWA. THERE IS LITTLE EXPECTED IN THE WAY OF PRECIPITATION, BUT IT SHOULD ALLOW TEMPERATURES COOL SOMEWHAT. IT WILL KEEP THE HIGH TEMPERATURES IN THE 70S THIS WEEK, WHICH IS NOT MUCH DIFFERENT THAN THE WEEKEND. HOWEVER, THE LOW TEMPERATURES WILL BE ABLE TO DROP INTO THE MID TO UPPER 40S IN THE NORTHWEST ZONES OF THE CWA. THE MAIN COLD AIR MASS DOES LOOK TO REMAIN WELL TO THE NORTH, SO TEMPERATURES ALONG THE COAST AND FAR SOUTH FLORIDA ARE EXPECTED TO ONLY DROP INTO THE LOW 60S, MAYBE UPPER 50S. BEYOND THE COLD FRONT, HIGH PRESSURE WILL SET UP ONCE AGAIN, WHICH WILL KEEP THE WEATHER QUIET FROM TUESDAY NIGHT THROUGH THE END OF THE WEEK, WITH HIGH TEMPERATURES SLOWLY RISING THROUGH THE WEEK. FIRE WEATHER... A STALLED FRONTAL BOUNDARY AND A DEVELOPING LOW PRESSURE SYSTEM NEAR THE AREA, WILL KEEP SHOWERS DEVELOPING ALONG THE ATLANTIC COAST AND KEEP ENOUGH SURFACE MOISTURE IN PLACE TO KEEP RH VALUES ABOVE ANY CRITICAL LEVELS. WINDS LOOK AS THOUGH THEY WILL BE LIGHTER THE ORIGINALLY THOUGH FOR THE NEXT COUPLE OF DAYS, WHICH WILL MEAN THEY WILL ALSO NOT REACH ANY CRITICAL LEVELS FOR THE NEXT SEVERAL DAYS. THERE WILL BE A COLD FRONT NEXT WEEK, WHICH MAY BRING SOME GUTSY WINDS AND A SLIGHT CHANCE FOR A SHOWER. BEHIND THIS FRONT, A MUCH DRIER AIR MASS IS EXPECTED. MIN RHS MAY DROP DOWN INTO THE MID 30 PERCENT RANGE IN THE NORTHWESTERN FIRE WEATHER ZONES. HOWEVER, WINDS ARE CURRENTLY EXPECTED TO REMAIN BELOW THRESHOLDS AT THIS TIME. MARINE... FOR THE GULF WATERS...SEAS ARE EXPECTED TO STEADILY SUBSIDE THE REMAINDER OF TODAY AS THE WINDS ACROSS THE REGION ARE FORECAST TO BECOME MORE NORTHEASTERLY AND SLOWLY SUBSIDE. FOR THE ATLANTIC WATERS...AS MODERATE NORTH TO NORTHEAST WINDS CONTINUE TO BUILD INTO THE REGION TODAY...THE ATLANTIC AND GULF STREAM SEAS ARE EXPECTED TO INCREASE THE REMAINDER OF TODAY THEN FORECAST TO BUILD QUICKLY TO ADVISORY LEVELS BY EARLY SATURDAY MORNING...MAINLY TO THE EAST OF PALM BEACH COUNTY...AND TO PERSIST THROUGH SATURDAY EVENING. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE ATLANTIC WATERS AT 00Z SUNDAY THIS EVENING. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 66 78 65 / 50 30 20 20 FORT LAUDERDALE 78 67 79 67 / 80 30 20 20 MIAMI 79 66 80 66 / 50 30 20 20 NAPLES 75 63 77 63 / 20 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM- COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
947 AM CST SAT JAN 19 2013 .SHORT TERM...TODAY THROUGH MONDAY NIGHT 947 AM CST SAT JAN 19 2013 947 AM UPDATE...FORECAST IN GENERAL REMAINS ON TRACK. POTENT SHORTWAVE WAS NOTED ON THE 15Z WATER VAPOR LOOP OVER SOUTHERN MANITOBA...WITH A 120-140 KT JET AT THE TROPOPAUSE DIGGING INTO THE DAKOTAS ON THE SOUTHWEST SIDE OF THE SHORTWAVE PER RAP ANALYSIS. DPVA AHEAD OF THE SHORTWAVE HAS RESULTED IN A DEEPENING SURFACE LOW...CURRENTLY AROUND 1002MB CENTERED OVER THE MN ARROWHEAD. TRAILING THE LOW IS AN ARCTIC COLD FRONT ALONG THE NORTH DAKOTA/SOUTH DAKOTA BORDER. SURFACE TEMPERATURES DROP FROM THE MID TO UPPER 30S FROM SOUTH DAKOTA INTO THE FORECAST AREA...INTO THE SINGLE DIGITS ABOVE ZERO OVER NORTHERN NORTH DAKOTA. WITH THE RAPID DROP IN TEMPERATURES IS A 2 MB/HR PRESSURE RISE OVER NORTH DAKOTA. THESE PRESSURE RISES AND A TIGHT PRESSURE GRADIENT BEHIND THE ARCTIC FRONT HAS RESULTED IN WINDS GUSTING 30-50 KT ACROSS NORTH DAKOTA INTO FAR NORTHWEST MN. THERE ARE ALSO SOME SNOW SHOWERS OCCURRING IMMEDIATELY BEHIND THE FRONT...AIDED BY LOW LEVEL FRONTOGENESIS. NAM/RAP/HRRR FORECASTS CONTINUE TO INDICATE THAT THE ARCTIC FRONT WILL CROSS THE FORECAST AREA BETWEEN 21-00Z...WITH WINDS AND GUSTS RAPIDLY INCREASING BEHIND THE FRONT AS INDICATED OVER NORTH DAKOTA. INTERESTING TO SEE THAT AT 00Z...THE RAP WIND GUSTS SHOW UPWARDS OF 40 KT OR SO ACROSS THE ENTIRE FORECAST AREA. NEEDLESS TO SAY...THE WIND ADVISORY LOOKS SOLID. PLUS...THE SURFACE LOW SHOULD BE ABLE TO DEEPEN A LITTLE MORE AS IT MOVES ACROSS THE WARMER LAKE SUPERIOR WATER...AND HAS THE SYNOPTIC SCALE IMPACT TO DEEPEN. THERE ARE 2 ISSUES PRIOR TO THE ARCTIC FRONT ARRIVAL...THOUGH. THE FIRST IS CLOUD COVER. FIRST BAND OF MID CLOUDS...ASSOCIATED WITH A SHORTWAVE SEEN ON WATER VAPOR STRETCHING FROM NORTHEAST NEBRASKA TO LA CROSSE...IS CLEARING OUT OF THE FORECAST AREA RIGHT NOW. ANOTHER BATCH OF MID CLOUDS HAVE DEVELOPED OVER CENTRAL MN...AHEAD OF ANOTHER WEAK SHORTWAVE. THESE CLOUDS APPEAR SLATED TO CROSS THE FORECAST AREA DURING THE NEXT FEW HOURS. HAVE INCREASED CLOUD COVER TO ACCOUNT FOR THESE. THERE STILL MAY BE ANOTHER BREAK IN CLOUDS BEFORE THE ARCTIC FRONT ARRIVES. WITH THE IN-AND-OUT PERIODS OF SUNSHINE AND 925MB TEMPS AROUND 5C PER 12Z MPX AND DVN RAOBS...CONCERNED TEMPERATURES ARE NOT HIGH ENOUGH. HRRR ACTUALLY HAS TEMPERATURES CLIMBING INTO THE LOW 50S OVER THE SOUTHERN HALF OF THE FORECAST AREA. HRRR DID VERY WELL YESTERDAY...ALBEIT WE DID HAVE FULL SUNSHINE. FOR NOW HAVE INCREASED TEMPERATURES SLIGHTLY...MAINLY SOUTH OF I-90. LASTLY...RAP AND 00Z/06Z NCEP HIRES ARW RUNS ARE IN GOOD AGREEMENT SHOWING THE BAND OF SNOW SHOWERS OVER SOUTHERN NORTH DAKOTA POST- FRONTAL DROPPING THROUGH MOST OF THE FORECAST AREA BETWEEN 18-00Z. PREVIOUS FORECAST HAD THIS COVERED WELL...JUST GAVE A LITTLE MORE TIMING AND SWITCHED TO A COVERAGE SNOW SHOWERS PHRASING SINCE THERE IS A CONVECTIVE NATURE TO THE PRECIPITATION. PREVIOUS DISCUSSION ISSUED AT 318 AM... THE MAIN FOCUS IS ON THE DRASTIC CHANGES THAT ARE ON TAP FOR TODAY AS A COLD FRONT DROPS THROUGH THE REGION. CURRENTLY...BROAD CYCLONIC FLOW ALOFT IS IN PLACE THROUGH MUCH OF CANADA AND THE US WITH THE CORE OF THE LOW CENTERED TO THE EAST OF HUDSON BAY LEAVING THE UPPER MISSISSIPPI RIVER VALLEY IN NORTHWESTERLY FLOW. DESPITE THIS...LOW LEVEL TEMPERATURES REMAIN MILD AT THE MOMENT WITH A SURFACE LOW OVER EASTERN NORTH DAKOTA AND A WARM FRONT EXTENDING TO THE EAST-SOUTHEAST ACROSS NORTHERN WISCONSIN. THIS MORNING WILL END UP BEING THE WARMEST PART OF THE DAY AS THIS SURFACE LOW TRACKS TO THE EAST TOWARD THE UP OF MICHIGAN. THIS FEATURE WILL BRING A COLD FRONT THROUGH THE REGION EARLY THIS AFTERNOON WITH WINDS SHIFTING TO THE NORTHWEST AND BECOMING STRONG POST-FROPA. NOT A WHOLE LOT OF CHANGES TO THE GOING WIND FORECAST WITH A TIGHTENING SURFACE PRESSURE GRADIENT...STRONG LOW LEVEL COLD AIR ADVECTION AND 3HR PRESSURE RISES OF 6-8MB SHOULD ALL LEAD TO STRONG AND GUSTY WINDS FOR A 6 TO 9 HOUR PERIOD LATE THIS AFTERNOON AND EVENING. SUBSIDENT AIR SHOULD HELP TO MIX DOWN SOME HIGHER GUSTS IN THE 45-50MPH RANGE...PARTICULARLY IN THE HIGHER ELEVATIONS IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA. BASED ON ALL THIS...THE WIND ADVISORY STILL LOOKS GOOD FOR THE REGION STARTING MID AFTERNOON AND ENDING AROUND MIDNIGHT AS THE WINDS DIMINISH. ANOTHER FEATURE WITH THIS FRONT IS THE BRIEF SHOT OF SNOW THAT WILL COME WITH IT. THE 19.00Z NAM AND MESO-MODELS SHOW A BAND OF SNOW FORMING OUT AHEAD OF THE COLD FRONT WHERE THE OVERALL FORCING IS A LITTLE STRONGER ACROSS SOUTHEAST MINNESOTA AND NORTH CENTRAL WISCONSIN. THIS WILL LEAD TO A SHORT PERIOD...LIKELY LESS THAN AN HOUR...OF SNOW WHICH COULD BRIEFLY BE HEAVY. THIS COULD LEAD TO A BRIEF DUSTING OF AROUND A HALF INCH OF SNOW AS IT COMES THROUGH. KEPT SOME FLURRIES THROUGH THE NIGHT ACROSS MUCH OF THE REGION DUE TO THE LOW LEVEL SATURATED LAYER BEING IN THE ICE LAYER OF -8C TO -20C...THOUGH THEY MAY NOT OCCUR IF THE SUBSIDENCE IS TOO STRONG AND CLEARS THINGS OUT. ALTHOUGH WINDS WILL BE ON THE DECREASE AFTER MIDNIGHT...THEY WILL STILL BE IN THE 10-20MPH RANGE AS THE COLDER AIR MOVES INTO THE REGION. BASED ON THE TEMPERATURE/WIND FORECAST...THERE COULD BE SOME -20F TO -25F WIND CHILLS THAT OCCUR ACROSS PORTIONS OF SOUTHEAST MINNESOTA AND NORTH CENTRAL WISCONSIN. THIS MAY WARRANT THE NEED FOR A WIND CHILL ADVISORY ONCE THE WIND ADVISORY ENDS. MAY STILL GO FOR ONE THIS MORNING...BUT AM STILL WORKING ON THE COLLABORATION WITH NEIGHBORING OFFICES AT THE MOMENT ON WHETHER TO GO FOR IT NOW OR LATER TODAY. BEYOND THIS ITS ALL ABOUT HOW COLD TEMPERATURES WILL GET WITH LITTLE TO NO SNOW PACK OUT THERE. A WEAKENING MID LEVEL TROUGH THAT HAS LITTLE LOW LEVEL SUPPORT WILL MOVE THROUGH ON SUNDAY AND COULD PROVIDE ANOTHER DUSTING OF SNOW...THOUGH CONFIDENCE IS NOT VERY HIGH ON THIS WITH THE WEAK MID LEVEL LIFT. HAD THE SNOW PACK NOT ERODED AWAY LAST WEEK...OUR TEMPERATURES WOULD LIKELY BE ABOUT 10 DEGREES COLDER THAN WHAT IS BEING FORECAST. DESPITE THIS...THE GUIDANCE ALL REMAINS IN GOOD AGREEMENT OF HAVING SUB-ZERO TEMPERATURES IN PLACE TO START NEXT WEEK. WIND CHILL ADVISORIES WILL DEFINITELY BE NEEDED FROM MONDAY MORNING THROUGH TUESDAY MORNING WITH WIND CHILLS IN THE -20F TO -30F RANGE. .LONG TERM...TUESDAY THROUGH FRIDAY 318 AM CST SAT JAN 19 2013 THE COLD AIR MASS APPEARS TO REMAIN IN PLACE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY THROUGH THE REST OF THE WEEK THOUGH IT DOES MODERATE SOME GOING INTO WEDNESDAY AND BEYOND AS THE RIDGE AXIS MOVES THROUGH AND THE CORE OF COLD LOW LEVEL AIR SHIFTS TO THE EAST. THERE ARE SOME HINTS THAT A SYSTEM WILL DROP DOWN THROUGH THE NORTHWEST FLOW ALOFT TUESDAY INTO TUESDAY NIGHT WHICH COULD BRING SOME SNOW ALONG WITH IT. THE 19.00Z GFS IS THE ONLY MODEL SHOWING THIS SNOW REACHING THE FORECAST AREA WITH THE 19.00Z ECMWF PLACING THE SURFACE RIDGE RIGHT ALONG THE MISSISSIPPI RIVER. SHOULD THE GFS PAN OUT...THERE COULD BE SOME HIGH RATIO SNOW THAT OCCURS WITH 19.00Z BUFKIT SOUNDINGS SHOWING A DEEP DENDRITIC GROWTH ZONE FROM THE SURFACE ON UP TO 700MB. THE BEST CHANCES FOR AN ACCUMULATING SNOW IS WITH A SYSTEM THAT MAY COME IN ON THURSDAY OR FRIDAY. THE 19.00Z GFS IS SLOW WITH THIS SYSTEM AND BRINGS IT IN THURSDAY NIGHT INTO FRIDAY WHILE THE 19.00Z ECMWF HAS IT THROUGH BY THURSDAY. THE 19.00Z GFS BUFKIT SOUNDINGS ARE EVEN DEEPER WITH THE DENDRITIC GROWTH ZONE AND LIFT WITH THIS SYSTEM...WHICH COULD AGAIN LEAD TO A HIGH SNOW TO LIQUID RATIO SNOW. TRENDED LOWER ON TEMPERATURES ON THURSDAY WITH GUIDANCE SHOWING THIS SYSTEM TRENDING A BIT FURTHER TO THE SOUTH. && .AVIATION...TODAY AND TONIGHT 551 AM CST SAT JAN 19 2013 ALL EYES ARE ON AN ARCTIC COLD FRONT THAT WILL BLAST THROUGH THE AREA THIS AFTERNOON. UNTIL THEN...EXPECT PATCHY ALTOCUMULUS WITH BASES AOA 10KFT. LOOK FOR SOUTHWEST WINDS IN ADVANCE OF THE FRONT THIS MORNING...THEN SHIFTING TO THE NORTHWEST AND INCREASING INTO THE 25-35KT RANGE WITH GUSTS INTO THE 40-45KT RANGE AROUND 21Z. THIS FRONTAL PASSAGE IS ALSO EXPECTED TO PRODUCE MVFR CLOUDS ALONG WITH SCATTERED SNOW SHOWER ACTIVITY. THESE STRONG WINDS AND LOCALLY REDUCED VISIBILITIES IN SCATTERED SNOW SHOWER ACTIVITY WILL LIKELY POSE PROBLEMS FOR BOTH GROUND AND AIRCRAFT OPERATIONS. LOOK FOR THE STRONG/GUSTY NORTHWEST WINDS TO SUBSIDE AFTER MIDNIGHT ALONG WITH SCATTERING CLOUDS. && .ARX WATCHES/WARNINGS/ADVISORIES... 551 AM CST SAT JAN 19 2013 WI...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR WIZ017-029-032>034-041>044-053>055-061. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR WIZ017-029. MN...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR MNZ079-086>088-094>096. IA...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR IAZ008>011-018-019-029-030. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...DAS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
912 AM MST SAT JAN 19 2013 .UPDATE... && .SHORT TERM...IN THE WAKE OF LAST NIGHTS WEAK TROF THERE IS STILL SOME GUSTY WINDS IN THE MOUNTAINS AND FOOTHILLS. THESE WINDS WILL CONTINUE TO DECREASE THIS AFTERNOON. BASED ON THE MORNING DENVER SOUNDING...TEMPERATURES MIGHT BE A DEGREE OR TWO COOLER FROM YESTERDAY WITH SLIGHT COOLING IN THE 600-700MB LAYER. WINDS EXPECTED TO INCREASE AGAIN LATER TONIGHT ALONG EAST SLOPES AS NEXT WEAK RIPPLE MOVES THROUGH THE FLOW. .AVIATION...CURRENT TAFS LOOK GOOD AND STILL PLANNING TO PLAY THE LONGMONT ANTICYCLONE THIS AFTERNOON WITH A LIGHT EAST TO SOUTHEAST WIND AT DEN AND APA. BJC MAY STILL SEE A MORE WESTERLY COMPONENT THIS AFTERNOON. && .PREV DISCUSSION... /ISSUED 243 AM MST SAT JAN 19 2013/ SHORT TERM...DRY NW FLOW ALOFT WILL CONTINUE TODAY AND TONIGHT. A MTN WAVE EARLY THIS MORNING IS ALLOWING FOR SOME GUSTY NWLY WINDS IN AND NR THE FOOTHILLS WHICH WILL LINGER THRU THE MID MORNING HOURS BEFORE DECREASING SOME BY MIDDAY. OTHERWISE GUSTY NW WINDS WILL ALSO OCCUR ALONG AND NR THE WY-NE BORDER ESPECIALLY LATER THIS MORNING INTO THE AFTN HOURS AS BETTER MIXING DEVELOPS. AS FOR HIGHS READINGS WILL BE IN THE 50S ACROSS NERN CO. ONCE AGAIN IN THE HIGHER MTN VALLEYS INVERSIONS WILL LEAD TO WIDE TEMP SPREADS ESPECIALLY ACROSS ZONE 32. FOR TONIGHT ANOTHER MTN WAVE MAY DEVELOP AFTER MIDNIGHT LEADING TO AN INCREASE IN WINDS OVER THE HIGHER MTNS AND FOOTHILLS. AT THIS TIME IT APPEARS SPEEDS SHOULD STAY BLO HIGHLIGHT CRITERIA. LONG TERM...NORTHWESTERLY FLOW ALOFT IS PROGGED TO CONTINUE OVER THE FORECAST AREA SUNDAY AND SUNDAY NIGHT. ON MONDAY...THE FLOW IS PROGGED TO BECOME NORTH-NORTHWESTERLY AND INCREASE A BIT IN SPEED. BY TUESDAY MORNING AT 12Z IT WEAKENS AND IS BACK TO A NORTHWESTERLY DIRECTION. AT THAT TIME AN UPPER RIDGE AXIS IS LOCATED OVER THE GREAT BASIN. THE SYNOPTIC SCALE ENERGY IS PROGGED TO BE BENIGN SUNDAY THROUGH MONDAY NIGHT. THE BOUNDARY LAYER FLOW LOOKS TO BE UPSLOPING FOR THE PLAINS AND FOOTHILLS SUNDAY...WITH NORMAL DUIRNAL PATTERNS FOR SUNDAY NIGHT INTO MONDAY. LOW LEVEL TROUHGING EAST OF THE MOUNTAINS SETS UP LATER SUNDAY THROUGH TUESDAY NIGHT...BUT THE GRADIENT IS PRETTY WEAK. A MIX OF NORMAL TRENDS TO DOWNSLOPING SHOULD PREVAIL THOSE TWO PERIODS. MOISTURE CONTINUES TO BE QUITE LIMITED ACCORDING TO THE MODELS. THERE IS A LITTLE OVER THE PLAINS WITH THE UPSLOPE SUNDAY AFTERNOON AND EVENING...MORE SO ON THE GFS. THE GFS ALSO SHOWS A TAD IN THE UPPER LEVELS MONDAY AND MONDAY NIGHT...BUT THAT`S ABOUT IT. THERE IS NO MEASURABLE PRECIPITATION NOTED ON THE QPF FIELDS FOR THE FORECAST AREA SUNDAY THROUGH MONDAY NIGHT. NO POPS. FOR TEMPERATURES...SUNDAY`S HIGHS ARE 4-8 C COLDER THAN TODAY`S EXPECTED HIGHS. MONDAY`S READINGS WARM UP 3-5 C OVER SUNDAY`S. FOR THE LATER DAYS...TUESDAY THROUGH FRIDAY...MODELS HAVE PRETTY WEAK NORTHWESTERLY FLOW ALOFT FOR THE CWA TUESDAY AND WEDNESDAY. BY THURSDAY...THE ECMWF AND GFS START DEVELOPING AN UPPER TROUGH NORTH AND NORTHEAST OF COLORADO. THE FLOW ALOFT INCREASES AND IS ZONAL ON THURSDAY. BY FRIDAY...A MEAN TROUGH IS PROGGED TO COVER THE EASTERN HALF OF NORTH AMERICA...AND AN UPPER RIDGE IS OVER THE GREAT BASIN. THE GFS BRINGS SOME MOISTURE OVER THE CWA THURSDAY AND THURSDAY NIGHT. THE ECMWF DOES NOT. THE OTHER DAYS ARE PRETTY DRY ON BOTH MODELS. WILL KEEP POPS OUT FOR NOW. TEMPERATURES REMAIN ABOVE SEASONAL NORMALS THROUGH THE PERIOD. AVIATION...WEST WINDS HAVE SPREAD ACROSS THE AIRPORT EARLY THIS MORNING BUT SHOULD BECOME MORE SWLY AFTER SUNRISE. BY 16Z WINDS MAY BECOME MORE SLY. FOR THIS AFTN THERE IS QUITE A DIFFERENCE IN WIND FCSTS AS THE HRRR AND RAP INDICATE A LONGMONT ANTI-CYCLONE DEVELOPING WITH WINDS BECOMING MORE ELY BY EARLY AFTN WHILE THE NAM HAS A WLY COMPONENT. WITH NWLY FLOW OVER THE CHEYENNE RIDGE THAT WOULD FAVOR A POTENTIAL ANTI-CYCLONE SO WILL TREND TAF TOWARDS THE HRRR/RAP SOLUTION. BY EARLY EVENING WINDS SHOULD GRADUALLY TRENDS TOWARDS DRAINAGE. VFR CONDITIONS WILL BE IN PLACE TODAY THRU TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...ENTREKIN LONG TERM....RJK AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS MIAMI FL
101 PM EST SAT JAN 19 2013 .AVIATION... LOW LEVEL TROUGH LOCATED NEAR KPBI WILL CONTINUE TO MOVE NORTHWARD UP THE COAST THROUGH THE DAY. RAIN HAS ENDED SOUTH OF KFXE...AND VFR CONDITIONS ARE EXPECTED SOUTH OF KFXE THROUGH TONIGHT. OLD FRONTAL BOUNDARY REMAINS JUST SOUTH OF THE REGION AND MOSTLY CLOUDY TO CLOUDY SKIES WILL PREVAIL THROUGH THE END OF THE PERIOD. SOME LOW CIGS/VIS MAY BE POSSIBLE FOR KAPF...KFXE...AND KTMB TONIGHT AS WINDS BECOME CALM AND A LAND BREEZE SETS UP. OTHERWISE...LIGHT NORTHEAST WINDS ARE EXPECTED THIS AFTERNOON...AND AGAIN AFTER 15Z SUNDAY. && .PREV DISCUSSION... /ISSUED 1104 AM EST SAT JAN 19 2013/ UPDATE...LOWERED POPS FOR BASED ON RADAR TRENDS. LOOKS LIKE WE WILL HAVE PREDOMINATELY SCATTERED SHOWER ACTIVITY FROM NE BROWARD AND ALONG THE PALM BEACH COAST WITH A SLIGHT CHANCE OF SHOWERS ELSEWHERE THROUGH THE DAY. SOME SUNSHINE NOW SOUTH WITH BREAKS DEVELOPING AT OTHER LOCALES SO IT LOOKS LIKE HIGHS ARE ON TRACK. /GREGORIA PREV DISCUSSION... /ISSUED 809 AM EST SAT JAN 19 2013/ UPDATE...UPDATED MOST ELEMENTS FOR CURRENT TRENDS. AREA OF LIGHT RAIN NOW IS FOCUSED ACROSS METRO BROWARD. HRRR AND NAM SHOW A GRADUALLY NORTHWARD SHIFT ALONG THE ATLANTIC COAST WITH TIME TODAY. NAM KEEPS A SOLID AREA OF QPF MOVING UP THE PALM BEACH COAST WHILE THE HRRR LESSENS QPF THIS AFTERNOON, SO TOOK A MIDDLE OF THE ROAD APPROACH. LOOKS LIKE TWO WEAK LOWS HAVE DEVELOPED...ONE OVER OUR ATLANTIC WATERS AND ANOTHER CLEARLY DEFINED ONE ON SAT IMAGERY OVER THE GULF OFF THE SW FL COAST. THESE FEATURES WILL KEEP EXTENSIVE CLOUDINESS OVER THE AREA TODAY, BUT WITH A FEW BREAKS EXPECTED IN THE AFTERNOON. THIS SHOULD MANAGE TO ALLOW TEMPS TO REACH FORECASTED HIGHS, BUT WILL NEED TO MONITOR THIS BC IF THERE ARE NO BREAKS, HIGHS MAY BE A TAD TOO WARM. IT DOESN`T TAKE MUCH BREAKS TO ACHIEVE OUR WARMER HIGHS ADVERTISED SO HAVE KEPT THE FCST AS IS FOR NOW FOR MAX T. /GREGORIA PREV DISCUSSION... /ISSUED 645 AM EST SAT JAN 19 2013/ AVIATION... MOSTLY CLOUDY SKIES WILL PREVAIL ACROSS SOUTH FLORIDA THIS MORNING. LIGHT DRAINAGE FLOW IS STILL PRESENT ACROSS THE EASTERN TERMINALS...BUT WILL SHIFT TO THE EAST BY 19/18Z. VCSH WAS KEPT AS PREVAILING AT ALL EASTERN TERMINALS EXCEPT FOR KPBI. SHOWERS WILL CONTINUE DEVELOPING THIS AFTERNOON...FOR THIS REASON KEPT VCSH AT ALL EASTERN TERMINALS THROUGH THE EVENING. FOR KAPF...DRY CONDITIONS EXPECTED THROUGH THE PERIOD. WIND FLOW WILL BE WEAK ENOUGH TO ALLOW FOR THE SEABREEZE TO DEVELOP BY 19/19Z. PREV DISCUSSION... /ISSUED 338 AM EST SAT JAN 19 2013/ DISCUSSION... AN ACTIVE NIGHT ALONG THE ATLANTIC COAST HAS BEEN THE CASE THIS MORNING. SHOWERS HAVE BEEN DEVELOPING ALL NIGHT ALONG A STALLED FRONTAL BOUNDARY, LAYING JUST TO THE SOUTHEAST OF THE CWA. MODELS ARE SHOWING A WEAK LOW FORMING ALONG THIS BOUNDARY, WHICH WILL ACT AS THE FOCAL POINT FOR CONTINUED DEVELOPMENT OF SHOWERS TODAY, MAINLY SCATTERED IN NATURE. THIS ACTIVITY WILL CONTINUE INTO THE EVENING HOURS AND BEGIN TO DIE DOWN TONIGHT. THE LOW THEN LOOKS TO FALL APART LATER ON SUNDAY. THERE LOOKS TO BE SOME UPPER LEVEL SUPPORT FOR THE SHOWERS TO BE NORTH, AS A JET STREAK WILL MOVE IN AND THE LEFT EXIT REGION WILL BE AROUND THE JAX AREA. KEPT A MENTION OF MAINLY A SLIGHT CHANCE OF COASTAL SHOWERS FOR THE NEXT FEW DAYS. FOR THE BEGINNING OF THE WEEK, A COLD FRONT, WITH AN ARCTIC PUSH, MOVES THROUGH THE CWA. THERE IS LITTLE EXPECTED IN THE WAY OF PRECIPITATION, BUT IT SHOULD ALLOW TEMPERATURES COOL SOMEWHAT. IT WILL KEEP THE HIGH TEMPERATURES IN THE 70S THIS WEEK, WHICH IS NOT MUCH DIFFERENT THAN THE WEEKEND. HOWEVER, THE LOW TEMPERATURES WILL BE ABLE TO DROP INTO THE MID TO UPPER 40S IN THE NORTHWEST ZONES OF THE CWA. THE MAIN COLD AIR MASS DOES LOOK TO REMAIN WELL TO THE NORTH, SO TEMPERATURES ALONG THE COAST AND FAR SOUTH FLORIDA ARE EXPECTED TO ONLY DROP INTO THE LOW 60S, MAYBE UPPER 50S. BEYOND THE COLD FRONT, HIGH PRESSURE WILL SET UP ONCE AGAIN, WHICH WILL KEEP THE WEATHER QUIET FROM TUESDAY NIGHT THROUGH THE END OF THE WEEK, WITH HIGH TEMPERATURES SLOWLY RISING THROUGH THE WEEK. FIRE WEATHER... A STALLED FRONTAL BOUNDARY AND A DEVELOPING LOW PRESSURE SYSTEM NEAR THE AREA, WILL KEEP SHOWERS DEVELOPING ALONG THE ATLANTIC COAST AND KEEP ENOUGH SURFACE MOISTURE IN PLACE TO KEEP RH VALUES ABOVE ANY CRITICAL LEVELS. WINDS LOOK AS THOUGH THEY WILL BE LIGHTER THE ORIGINALLY THOUGH FOR THE NEXT COUPLE OF DAYS, WHICH WILL MEAN THEY WILL ALSO NOT REACH ANY CRITICAL LEVELS FOR THE NEXT SEVERAL DAYS. THERE WILL BE A COLD FRONT NEXT WEEK, WHICH MAY BRING SOME GUTSY WINDS AND A SLIGHT CHANCE FOR A SHOWER. BEHIND THIS FRONT, A MUCH DRIER AIR MASS IS EXPECTED. MIN RHS MAY DROP DOWN INTO THE MID 30 PERCENT RANGE IN THE NORTHWESTERN FIRE WEATHER ZONES. HOWEVER, WINDS ARE CURRENTLY EXPECTED TO REMAIN BELOW THRESHOLDS AT THIS TIME. MARINE... FOR THE GULF WATERS...SEAS ARE EXPECTED TO STEADILY SUBSIDE THE REMAINDER OF TODAY AS THE WINDS ACROSS THE REGION ARE FORECAST TO BECOME MORE NORTHEASTERLY AND SLOWLY SUBSIDE. FOR THE ATLANTIC WATERS...AS MODERATE NORTH TO NORTHEAST WINDS CONTINUE TO BUILD INTO THE REGION TODAY...THE ATLANTIC AND GULF STREAM SEAS ARE EXPECTED TO INCREASE THE REMAINDER OF TODAY THEN FORECAST TO BUILD QUICKLY TO ADVISORY LEVELS BY EARLY SATURDAY MORNING...MAINLY TO THE EAST OF PALM BEACH COUNTY...AND TO PERSIST THROUGH SATURDAY EVENING. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE ATLANTIC WATERS AT 00Z SUNDAY THIS EVENING. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 66 78 65 78 / 30 20 20 20 FORT LAUDERDALE 67 79 67 79 / 30 20 20 20 MIAMI 66 80 66 80 / 30 20 20 20 NAPLES 63 77 63 76 / 10 10 10 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM- COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...57/DG AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS MIAMI FL
1104 AM EST SAT JAN 19 2013 .UPDATE...LOWERED POPS FOR BASED ON RADAR TRENDS. LOOKS LIKE WE WILL HAVE PREDOMINATELY SCATTERED SHOWER ACTIVITY FROM NE BROWARD AND ALONG THE PALM BEACH COAST WITH A SLIGHT CHANCE OF SHOWERS ELSEWHERE THROUGH THE DAY. SOME SUNSHINE NOW SOUTH WITH BREAKS DEVELOPING AT OTHER LOCALES SO IT LOOKS LIKE HIGHS ARE ON TRACK. /GREGORIA && .PREV DISCUSSION... /ISSUED 809 AM EST SAT JAN 19 2013/ UPDATE...UPDATED MOST ELEMENTS FOR CURRENT TRENDS. AREA OF LIGHT RAIN NOW IS FOCUSED ACROSS METRO BROWARD. HRRR AND NAM SHOW A GRADUALLY NORTHWARD SHIFT ALONG THE ATLANTIC COAST WITH TIME TODAY. NAM KEEPS A SOLID AREA OF QPF MOVING UP THE PALM BEACH COAST WHILE THE HRRR LESSENS QPF THIS AFTERNOON, SO TOOK A MIDDLE OF THE ROAD APPROACH. LOOKS LIKE TWO WEAK LOWS HAVE DEVELOPED...ONE OVER OUR ATLANTIC WATERS AND ANOTHER CLEARLY DEFINED ONE ON SAT IMAGERY OVER THE GULF OFF THE SW FL COAST. THESE FEATURES WILL KEEP EXTENSIVE CLOUDINESS OVER THE AREA TODAY, BUT WITH A FEW BREAKS EXPECTED IN THE AFTERNOON. THIS SHOULD MANAGE TO ALLOW TEMPS TO REACH FORECASTED HIGHS, BUT WILL NEED TO MONITOR THIS BC IF THERE ARE NO BREAKS, HIGHS MAY BE A TAD TOO WARM. IT DOESN`T TAKE MUCH BREAKS TO ACHIEVE OUR WARMER HIGHS ADVERTISED SO HAVE KEPT THE FCST AS IS FOR NOW FOR MAX T. /GREGORIA PREV DISCUSSION... /ISSUED 645 AM EST SAT JAN 19 2013/ AVIATION... MOSTLY CLOUDY SKIES WILL PREVAIL ACROSS SOUTH FLORIDA THIS MORNING. LIGHT DRAINAGE FLOW IS STILL PRESENT ACROSS THE EASTERN TERMINALS...BUT WILL SHIFT TO THE EAST BY 19/18Z. VCSH WAS KEPT AS PREVAILING AT ALL EASTERN TERMINALS EXCEPT FOR KPBI. SHOWERS WILL CONTINUE DEVELOPING THIS AFTERNOON...FOR THIS REASON KEPT VCSH AT ALL EASTERN TERMINALS THROUGH THE EVENING. FOR KAPF...DRY CONDITIONS EXPECTED THROUGH THE PERIOD. WIND FLOW WILL BE WEAK ENOUGH TO ALLOW FOR THE SEABREEZE TO DEVELOP BY 19/19Z. PREV DISCUSSION... /ISSUED 338 AM EST SAT JAN 19 2013/ DISCUSSION... AN ACTIVE NIGHT ALONG THE ATLANTIC COAST HAS BEEN THE CASE THIS MORNING. SHOWERS HAVE BEEN DEVELOPING ALL NIGHT ALONG A STALLED FRONTAL BOUNDARY, LAYING JUST TO THE SOUTHEAST OF THE CWA. MODELS ARE SHOWING A WEAK LOW FORMING ALONG THIS BOUNDARY, WHICH WILL ACT AS THE FOCAL POINT FOR CONTINUED DEVELOPMENT OF SHOWERS TODAY, MAINLY SCATTERED IN NATURE. THIS ACTIVITY WILL CONTINUE INTO THE EVENING HOURS AND BEGIN TO DIE DOWN TONIGHT. THE LOW THEN LOOKS TO FALL APART LATER ON SUNDAY. THERE LOOKS TO BE SOME UPPER LEVEL SUPPORT FOR THE SHOWERS TO BE NORTH, AS A JET STREAK WILL MOVE IN AND THE LEFT EXIT REGION WILL BE AROUND THE JAX AREA. KEPT A MENTION OF MAINLY A SLIGHT CHANCE OF COASTAL SHOWERS FOR THE NEXT FEW DAYS. FOR THE BEGINNING OF THE WEEK, A COLD FRONT, WITH AN ARCTIC PUSH, MOVES THROUGH THE CWA. THERE IS LITTLE EXPECTED IN THE WAY OF PRECIPITATION, BUT IT SHOULD ALLOW TEMPERATURES COOL SOMEWHAT. IT WILL KEEP THE HIGH TEMPERATURES IN THE 70S THIS WEEK, WHICH IS NOT MUCH DIFFERENT THAN THE WEEKEND. HOWEVER, THE LOW TEMPERATURES WILL BE ABLE TO DROP INTO THE MID TO UPPER 40S IN THE NORTHWEST ZONES OF THE CWA. THE MAIN COLD AIR MASS DOES LOOK TO REMAIN WELL TO THE NORTH, SO TEMPERATURES ALONG THE COAST AND FAR SOUTH FLORIDA ARE EXPECTED TO ONLY DROP INTO THE LOW 60S, MAYBE UPPER 50S. BEYOND THE COLD FRONT, HIGH PRESSURE WILL SET UP ONCE AGAIN, WHICH WILL KEEP THE WEATHER QUIET FROM TUESDAY NIGHT THROUGH THE END OF THE WEEK, WITH HIGH TEMPERATURES SLOWLY RISING THROUGH THE WEEK. FIRE WEATHER... A STALLED FRONTAL BOUNDARY AND A DEVELOPING LOW PRESSURE SYSTEM NEAR THE AREA, WILL KEEP SHOWERS DEVELOPING ALONG THE ATLANTIC COAST AND KEEP ENOUGH SURFACE MOISTURE IN PLACE TO KEEP RH VALUES ABOVE ANY CRITICAL LEVELS. WINDS LOOK AS THOUGH THEY WILL BE LIGHTER THE ORIGINALLY THOUGH FOR THE NEXT COUPLE OF DAYS, WHICH WILL MEAN THEY WILL ALSO NOT REACH ANY CRITICAL LEVELS FOR THE NEXT SEVERAL DAYS. THERE WILL BE A COLD FRONT NEXT WEEK, WHICH MAY BRING SOME GUTSY WINDS AND A SLIGHT CHANCE FOR A SHOWER. BEHIND THIS FRONT, A MUCH DRIER AIR MASS IS EXPECTED. MIN RHS MAY DROP DOWN INTO THE MID 30 PERCENT RANGE IN THE NORTHWESTERN FIRE WEATHER ZONES. HOWEVER, WINDS ARE CURRENTLY EXPECTED TO REMAIN BELOW THRESHOLDS AT THIS TIME. MARINE... FOR THE GULF WATERS...SEAS ARE EXPECTED TO STEADILY SUBSIDE THE REMAINDER OF TODAY AS THE WINDS ACROSS THE REGION ARE FORECAST TO BECOME MORE NORTHEASTERLY AND SLOWLY SUBSIDE. FOR THE ATLANTIC WATERS...AS MODERATE NORTH TO NORTHEAST WINDS CONTINUE TO BUILD INTO THE REGION TODAY...THE ATLANTIC AND GULF STREAM SEAS ARE EXPECTED TO INCREASE THE REMAINDER OF TODAY THEN FORECAST TO BUILD QUICKLY TO ADVISORY LEVELS BY EARLY SATURDAY MORNING...MAINLY TO THE EAST OF PALM BEACH COUNTY...AND TO PERSIST THROUGH SATURDAY EVENING. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE ATLANTIC WATERS AT 00Z SUNDAY THIS EVENING. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 66 78 65 / 40 30 20 20 FORT LAUDERDALE 78 67 79 67 / 20 30 20 20 MIAMI 79 66 80 66 / 20 30 20 20 NAPLES 75 63 77 63 / 20 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR COASTAL WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM- COASTAL WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20 NM TO 60 NM. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS DULUTH MN
336 PM CST SAT JAN 19 2013 .SHORT TERM.../NOW - SUNDAY NIGHT/ THE MAIN CHALLENGES FOR THIS FORECAST INCLUDE 1) THE THREAT OF STRONG WINDS ACROSS THE NORTHLAND THROUGH TONIGHT IN THE WAKE OF A STRONG COLD FRONT...2) THE THREAT OF LAKE EFFECT SNOW FOR THE GOGEBIC RANGE AND 3) THE THREAT OF HAZARDOUS WIND CHILL VALUES TONIGHT AND TOMORROW MORNING. THE MODELS ARE IN REASONABLE AGREEMENT...SO LEANED ON A BLEND. THE LATEST HIGH RESOLUTIONS MODELS INDICATE STRONG WIND GUSTS ALONG THE NORTH SHORE TONIGHT...SO ISSUED A WIND ADVISORY FOR THE NORTH SHORE THAT IS SEPARATE FROM THE WIND ADVISORY FOR PARTS OF EAST CENTRAL MINNESOTA AND NORTHWESTERN WISCONSIN. AT 2130Z...THERE WAS A STRONG CLIPPER SYSTEM CENTERED OVER UPPER PENINSULA MICHIGAN. THE NORTHLAND HAD STRONG W TO NW WINDS...WHICH WERE GENERALLY STRENGTHENING IN THE WAKE OF THE CLIPPER. THE NORTHLAND HAD CLOUDY SKIES. TEMPERATURES RANGED FROM THE LOW TO MID 30S IN THE FAR EASTERN FA TO THE SINGLE DIGITS IN THE FAR NW FA. THROUGH TONIGHT...THE CLIPPER SYSTEM WILL CONTINUE TO MOVE EAST. THE STRONG NW WINDS CARRYING QUITE THE ARCTIC BLAST WILL CONTINUE TO INCREASE LATE THIS AFTERNOON...PERHAPS PEAK EARLY THIS EVENING...THEN GRADUALLY RELAX THROUGH THE REST OF THE NIGHT. THE EXCEPTION COULD BE ALONG THE IMMEDIATE NORTH SHORE WHERE WINDS...ESPECIALLY GUSTS...WILL LIKELY STRENGTHEN INTO THIS EVENING AND PEAK AROUND MIDNIGHT. THIS IS BASED ON THE LATEST RUNS OF THE HRRR AND LOCAL WRF MODELS. THOSE MODELS SUGGEST WIND GUSTS UP TO 50 KT. NOT SURE IF THE GUSTS WILL BE THAT STRONG...BUT DECIDED TO ISSUE A WIND ADVISORY FOR THE NORTH SHORE THROUGH 09Z TONIGHT FOR GUSTS UP TO 50 MPH. THE CURRENT WIND ADVISORY FROM SOUTHERN CASS COUNTY TO BURNETT COUNTY STILL LOOKS GOOD THROUGH 03Z. WIND CHILL VALUES WILL PLUMMET TONIGHT WITH THE FALLING TEMPERATURES...AND THE CURRENT WIND CHILL ADVISORY FOR TONIGHT AND INTO TOMORROW MORNING DOES NOT NEED ANY CHANGES. LAKE EFFECT SNOW SHOWERS WILL INCREASE ACROSS THE SOUTH SHORE TONIGHT...ESPECIALLY THE GOGEBIC RANGE IN IRON COUNTY...AS THE STRONG COLD NW WINDS DEVELOP OVER WESTERN LAKE SUPERIOR. WILL NOT BE MAKING CHANGES TO THE CURRENT LAKE EFFECT SNOW ADVISORY FOR IRON COUNTY AS PARTS OF THE COUNTY COULD GET SEVERAL INCHES OF SNOW THROUGH SUNDAY MORNING. SUNDAY AND SUNDAY NIGHT...IT WILL BE A PARTICULARLY COLD DAY ACROSS THE NORTHLAND WITH MUCH OF REGION NOT EVEN REACHING ZERO DEGREES. LAKE EFFECT SNOW SHOWERS WILL LIKELY CONTINUE FOR THE SOUTH SHORE. ANOTHER WIND CHILL ADVISORY OR WARNING WILL LIKELY BE NEEDED. SOME PARTS OF FAR NORTHERN MINNESOTA COULD HAVE WIND CHILL VALUES APPROACHING 50 DEGREES BELOW ZERO. .LONG TERM.../MONDAY - FRIDAY NIGHT/ MODELS SHOWING GOOD AGREEMENT THAT THE CORE OF COLDEST H85-H50 AIR PUSHES INTO THE NORTHERN AREAS EARLY MONDAY MORNING...SWINGING THROUGH THE NORTHLAND THROUGH 00Z TUESDAY. AT THIS TIME WIND CHILL VALUES IN THE NEIGHBORHOOD OF NEGATIVE 30 TO 50 ARE EXPECTED EARLY MONDAY MORNING WITH VERY LITTLE IMPROVEMENT THROUGH THE DAY. THE LATEST ECM/GFS SUGGEST THAT THE WRN LAKE SUPERIOR REGION REMAINS ON THE BACK EDGE OF THE ARCTIC AIR MASS THROUGH MUCH OF THE WEEK WITH A PERSIST ANT NORTHWEST FLOW. HAVE KEPT POPS ACROSS THE SOUTH SHORE ZONES FOR AN ONGOING PERIOD OF LAKE EFFECT SNOW AS WELL. && .AVIATION.../18Z TAF ISSUANCE/ MVFR CIGS WITH -SN AND BLSN WILL PREVAIL THROUGH 00Z..THEN GRADUALLY IMPROVING TO VFR GENERALLY AFTER 06Z. NORTHWEST WINDS WILL INCREASE THROUGH THE AFTERNOON WITH GUSTS OF 30 TO 35 KTS COMMON ACROSS THE FORECAST ARES THROUGH THE 20Z TO 06Z PERIOD. HIGHER GUSTS AROUND 40 KT WILL BE POSSIBLE AT THE KBRD AND KDLH TERMINALS AROUND 00Z...WITH THE STRONGEST GUSTS OF 45-50 KT EXPECTED ALONG THE NORTH SHORE OF LAKE SUPERIOR AFTER 03Z. && .POINT TEMPS/POPS... DLH -12 0 -21 -9 / 10 10 10 10 INL -19 -5 -30 -12 / 10 10 10 10 BRD -12 1 -22 -10 / 10 10 10 0 HYR -5 3 -18 -7 / 20 10 10 10 ASX -1 6 -13 -4 / 60 30 50 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO NOON CST SUNDAY FOR MNZ010>012-018>021-025-026-033>038. WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ033-034-036-038. WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR MNZ020-021. WI...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR WIZ006. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY FOR WIZ001>004-006>009. LAKE EFFECT SNOW ADVISORY UNTIL NOON CST SUNDAY FOR WIZ004. LS...NONE. && $$ SHORT TERM...GROCHOCINSKI LONG TERM....GRANING AVIATION...GRANING
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
306 PM CST SAT JAN 19 2013 .DISCUSSION... FORECAST CONCERNS FOR THE 7 DAY PERIOD AHEAD ARE MAINLY CONFINED TO THE NEXT 48 HOURS. THE ARCTIC BOUNDARY IS PASSING THROUGH THE CWA AS FORECAST THIS AFTERNOON. SUSTAINED WINDS NEAR 30 MPH WITH GUSTS REACHING 55 MPH HAVE BEEN COMMON IN THE WAKE OF THE FRONT. THE BOUNDARY IS MOVING THROUGH THE TWIN CITIES AT THIS TIME. THE FRONT WILL BE PAST KEAU TO THE IA BORDER BY 5 PM. THE WIND ADVISORY WILL REMAIN IN EFFECT CWA-WIDE THROUGH 9 PM. SOME FLURRY ACTIVITY CAN NOT BE RULED OUT AS WELL IN THE CLOUD STREETS THAT STRETCH BACK TO THE CANADIAN BORDER. OF GREATER CONCERN...WE DEFINITELY HAVE DRIFTING SNOW ACROSS THE NW CWA AROUND KAXN BASED ON MULTIPLE WEB CAMS. THE VISIBILITY IS NOT TOO BAD...BUT IT DOES BECOME MUCH WORSE NW OF OUR CWA TOWARDS FERGUS FALLS AND FARGO. HAVE ADDED BLOWING SNOW TO THE GRIDS FOR THE LATE AFTERNOON/ EVENING HOURS TO AREAS WEST OF A KLXL TO KOVL LINE ALONG WITH ISSUING AN SPS. AS THE EVENING PROGRESSES AND TEMPERATURES CONTINUE TO PLUMMET...WIND CHILL VALUES BECOME CRITICAL ACROSS CENTRAL MN AND PARTS OF WEST CENTRAL WI. THE CURRENT WIND CHILL ADVISORIES LOOK OKAY WITH THE ONE ACROSS CENTRAL MN BEGINNING AFTER 9 PM AND IN WEST CENTRAL WI AFTER MIDNIGHT. AT THIS POINT...THE WIND CHILL VALUES OF 25 BELOW ARE MOST WIDESPREAD ACROSS CENTRAL MN OVERNIGHT AND SUNDAY MORNING. A DISTURBANCE MOVING SOUTHEAST ACROSS THE PLAINS ON SUNDAY WILL BRING A PERIOD OF SNOW THAT WILL BRUSH WEST CENTRAL THROUGH SOUTH CENTRAL MN. THE MODELS HAVE BEEN PRETTY CONSISTENT WITH THIS FEATURE FOR THE PAST FEW DAYS ALTHOUGH A SLIGHT SOUTHWEST DRIFT HAS OCCURRED WITH TIME. THE SREF SHOWS 18 OF 21 MEMBERS MEASURING ALONG AND SOUTH THE MN RIVER VALLEY. AS A RESULT...RAISED POPS IN THESE AREAS TO 60-80 PERCENT BASED ON THE ABOVE ALONG WITH THE MID LEVEL FRONTOGENESIS AND THE LOW CONDENSATION PRESSURE DEFICITS/ ADIABATIC OMEGA MOVING THROUGH ON THE 280K SURFACE. CARIBOU SNOW TECHNIQUE PRETTY CONSISTENT AS WELL BETWEEN THE NAM/GFS AND SREF ON SNOW AMOUNTS BEING AROUND A HALF INCH...ALTHOUGH THE GRIDS REFLECT FROM A HALF INCH TO NEARLY AN INCH. ITS INTERESTING TO NOTE THAT THE SATURATED COLUMN ACROSS THE SW CWA ON SUNDAY IS AT OR BELOW -18 DEG C. THIS WOULD BE MORE PLATES AND COLUMNS WITH THE DENDRITIC DEVELOPMENT. THE HEART OF THE ARCTIC AIR WILL BE FROM SUNDAY NIGHT THROUGH TUESDAY. MORE WIND CHILL PRODUCTS WILL LIKELY BE NEEDED SUNDAY NIGHT AND MONDAY WITH CURRENT GRIDDED WIND CHILL VALUES IN THE 25 BELOW TO 45 BELOW ZERO RANGE. OVERNIGHT LOWS SUNDAY NIGHT AND MONDAY NIGHT PRETTY MUCH BETWEEN 10 BELOW AND 20 BELOW ZERO ACROSS THE CWA. THE HIGHS ON MONDAY ARE STILL PROGGED BELOW ZERO ACROSS THE ENTIRE CWA. THERE WILL BE SLOW MODERATION TO THE TEMPERATURES IN THE MID WEEK PERIOD. THERE ALSO REMAINS A CHANCE OF LIGHT SNOW FROM THURSDAY INTO FRIDAY AS A PACIFIC SHORT WAVE MOVES THROUGH. ONE OF THE PROBLEMS SEEN WITH THIS SYSTEM IS THAT THE MODELS ARE TRYING TO SHOW BOTH NORTHERN AND SOUTHERN STREAM ENERGY. WE COULD END UP WITH A SPLIT PRECIPITATION PATTERN ACROSS THE UPPER MISSISSIPPI VALLEY REGION. HENCE...CHANCE POPS CONTINUE WITH LOW CONFIDENCE ON THE OUTCOME. IT WILL LIKELY TURN COLD AGAIN HEADING INTO NEXT WEEKEND IN THE WAKE OF THIS SYSTEM WITH BELOW ZERO TEMPERATURES FOR SATURDAY MORNING. && .AVIATION... /18Z TAF ISSUANCE/ SFC LOW NOW MOVING OVER LK SUPERIOR...WITH THE ARCTIC COLD FRONT NOW STARTING ON A TEAR SOUTH ACROSS MN. WAS INITIALLY THINKING OF SCALING GUSTS BACK SOME...SINCE GUSTS ACROSS NRN MN/NODAK WERE ONLY GUSTING IN THE MID 30S...BUT AS OBS AROUND 1730Z STARTED ROLLING...STARTED TO SEE GUSTS OVER 40 KTS ACROSS WEST CENTRAL MN RIGHT BEHIND THE BOUNDARY...SO LEFT BIG GUSTS IN PLACE. STILL EXPECT A 2 OR 3 HOUR WINDOW WITH SUSTAINED WINDS 30-35 KTS WITH GUSTS 40 TO 45 KTS IMMEDIATELY BEHIND THE FRONT...BEFORE SUSTAINED SPEEDS AND GUSTS SETTLE DOWN ABOUT 10 KTS. FRONT ALSO COMING DOWN WITH MVFR CIGS BETWEEN 010 AND 020. THESE CLOUDS WILL REMAIN IN PLACE THROUGH THE AFTERNOON...BUT CLEARING IS SEEN MOVING SOUTH ACROSS NODAK THIS AFTERNOON. CURRENTLY CLOCKING THIS CLEARING MOVING SOUTH AT ABOUT 50 KTS...SO A RETURN TO VFR CONDS MAY COME ABOUT FASTER THAN CURRENTLY INDICATED. THIS TREND TO VFR CIGS IS SUPPORTED BY THE SREF...WHICH HAS MUCH OF THE MPX CWA VFR OVERNIGHT...BEFORE BRINGING ANOTHER ROUND OF MVFR CIGS IN FROM THE DAKOTAS LATE TONIGHT. AS FOR WX...THERE WILL BE TWO CHANCES FOR SNOW. FIRST WILL BE BEHIND THE COLD FRONT THIS AFTERNOON...THOUGH THIS LOOKING LESS LIKELY OUTSIDE OF CENTRAL MN. RAP SOUNDINGS SHOW POST FRONTAL CLOUD LAYER REACHING UP INTO THE SNOW GROWTH ZONE NORTH...BUT AS YOU HEAD TOWARD MSP/EAU...THE POST FRONTAL CLOUD LAYER IS FORECAST TO BE TOO WARM TO GENERATE ICE CRYSTALS...SO CUT BACK ON SNOW MENTION OUTSIDE OF CENTRAL MN. SECOND CHANCE WILL COME TONIGHT AS AN UPPER WAVE MOVES ACROSS AN ELEVATED FRONTAL BOUNDARY ACROSS SW MN. MOST OF THE SNOW LOOKS TO STAY SW OF MPX TERMINALS...THOUGH RWF LOOKS TO GET A PERIOD OF -SN IN THE MORNING. KMSP...MVFR CIGS ALREADY MOVING INTO THE NW METRO AND SHOULD BE IN AT MSP WITHIN THE FIRST HOUR. WILL START SEEING GUSTS PICK UP WITH THE ARRIVAL OF THE CLOUDS...THOUGH GUSTS NEAR 40 KTS ARE TRAILING THE CLOUDS BY A BIT...THOUGH MAY SEE STRONGER GUSTS SHOW UP A BIT EARLIER THAN 22Z. ALSO PULLED BACK ON SNOW BASED ON WARMER FORECAST CLOUD LAYER...BUT LOOKING AT IR...IS A NICE BAND OF COOLER TOPS MOVING SOUTH ACROSS CENTRAL MN AT THE MOMENT. IF THIS CAN HOLD TOGETHER...MAY NEED TO MENTION AN IFR VIS MENTION IN -SN BETWEEN 21Z AND 23Z. SREF HAS A GOOD HANDEL ON CLEARING CURRENTLY MOVING ACROSS NODAK...SO FOLLOWED IT IN BRINGING VFR CONDITION BACK IN TONIGHT. SNOW MOVING INTO SW MN LOOKS TO REMAIN WELL SW OF MSP...BUT CAN NOT RULE OUT A FLURRY OR TWO WITH MVFR CONDS MOVING BACK IN BY SUNDAY AFTERNOON. /OUTLOOK FOR KMSP/ MON...MVFR CIGS POSSIBLE EARLY. WINDS NW 10 KTS. TUE...VFR. WINDS W 5 KTS. WED...VFR. WINDS SW 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS- FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC- KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE- SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD- WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE. WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM CST SUNDAY FOR BENTON-DOUGLAS-ISANTI-KANABEC-MILLE LACS-MORRISON-POPE- SHERBURNE-STEARNS-STEVENS-TODD. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST SUNDAY FOR ANOKA-CHISAGO. WI...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR BARRON-CHIPPEWA- DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST SUNDAY FOR BARRON-CHIPPEWA-DUNN-POLK-RUSK-ST. CROIX. && $$ RAH/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1240 PM CST SAT JAN 19 2013 .UPDATE... 18Z AVIATION DISCUSSION ADDED BELOW. && UPDATE... /ISSUED 1043 AM CST SAT JAN 19 2013/ COUPLE OF CHANGES MADE TO GRIDS THIS MORNING. BIGGEST CHANGE WAS TO LOWER POPS FOR THIS AFTERNOON...WITH POPS NOW UNDER 50% WITH SCT SNOW SHOWERS WORDING NOTED. THIS WAS BASED ON FORECAST SOUNDINGS FROM THE RAP. YES WE ARE STILL SEEING AGGRESSIVE CAA WITH UNSTABLE LOW LEVEL LAPSE RATES...BUT THERE IS NO SATURATION NOTED WITHIN THE DENDRITIC GROWTH ZONE. SO DESPITE SEEING EXTENSIVE CLOUD COVER...DOUBTING WHETHER THERE WILL BE MUCH OF ANY ACTIVITY BEHIND THE COLD FRONT...WHICH AT 1030AM WAS JUST BEGINNING TO PUSH INTO THE NRN PORTION OF THE MPX MN CWA. ONLY OTHER CHANGES WERE MINOR TIMING CHANGES TO WIND SPEED INCREASE AND TEMP/DEWP DROPS BEHIND THE COLD FRONT. WITH MAIN FRONT COMING IN A LITTLE SLOWER THAN WHAT WAS EXPECTED THIS MORNING...DELAYED THE SPEED INCREASE AND TEMP DROPS BY A COUPLE OF HOURS...BUT STILL LOOKING QUITE BLUSTERY WITH AGGRESSIVE TEMP DROPS ONCE THE FRONT GOES THROUGH...AS SEEN IN FARGO WHERE IT WENT FROM 36 AT 14Z DOWN TO 18 AT 16Z...SO LOSING NEARLY 10 DEGS PER HOUR. PREV DISCUSSION... /ISSUED 615 AM CST SAT JAN 19 2013/ BIG CHANGE IN THE WEATHER WILL COMMENCE TODAY. LOCAL WRF MODEL MEAN DOES INDICATE THE NORTHERN CWA WILL SEE SOME SNOW SHOWERS AS STRONG COLD FRONT DROPS SOUTHEAST OVER THE AREA. APPEARS FRONT WILL BE LOCATED JUST NORTH OF KMSP THROUGH 18Z. THEN EXITING THE FAR SOUTH THROUGH 23Z. STRONG NORTHWEST WINDS DEVELOPING BEHIND FRONT WITH STRONG CAA PATTERN AND STEEP LAPSE RATES DEVELOPING. THIS ALONG WITH PV ANOMALY SHOULD BE ENOUGH TO DRIVE 45-50 MPH WIND GUSTS OVER MUCH OF THE AREA INTO THE AFTERNOON WITH FROPA. WILL CONTINUE THE WIND ADV FOR THE REGION THROUGH 9 PM. TEMPERATURES EXPECTED TO TUMBLE RAPIDLY AS WELL AFTER FROPA...INTO THE SINGLE DIGITS NORTHWEST AND THROUGH THE TEENS IN THE SOUTHEAST. WILL NEED WIND CHILL ADVISORY FOR NORTHERN PORTION OF THE CWA DURING THE NIGHT AND SATURDAY MORNING. COLD AIR DROPS OVER THE AREA THE NEXT SEVERAL DAYS AS 1050MB HIGH MOVES ACROSS THE DAKOTAS WITH MINUS 28 TO MINUS 30 CELSIUS H85 AIR MOVING ACROSS THE AREA. ANOTHER WEAK SHORT WAVE MOVES ACROSS THE AREA SUNDAY AND CONTINUED SOME CHANCE POPS...MAINLY TO THE SOUTHWEST. THE CORE OF COLDEST AIR TO MOVE THROUGH MONDAY WITH THE ENTIRE CWA EXPECTED TO REMAIN BELOW ZERO. WIND CHILL WARNING/ADVISORY WILL MOST LIKELY BE NEEDED AGAIN SUNDAY NIGHT PERHAPS LINGERING THROUGH MONDAY NIGHT OR TUESDAY MORNING. MODERATION OF THE ARCTIC AIR THEN TAKES PLACE AFTER TUESDAY. LONGER TERM MODELS SUGGEST ANOTHER MORE SIGNIFICANT WAVE MOVES INTO THE REGION THURSDAY INTO FRIDAY WITH ANOTHER SHOT AT SOME ACCUMULATING SNOW. COLDER AIR FOLLOWS THIS SYSTEM AS WELL...BUT NOT AS COLD AS THE AIR MOVING IN EARLY IN THE PERIOD. && .AVIATION.../18Z TAF ISSUANCE/ SFC LOW NOW MOVING OVER LK SUPERIOR...WITH THE ARCTIC COLD FRONT NOW STARTING ON A TEAR SOUTH ACROSS MN. WAS INITIALLY THINKING OF SCALING GUSTS BACK SOME...SINCE GUSTS ACROSS NRN MN/NODAK WERE ONLY GUSTING IN THE MID 30S...BUT AS OBS AROUND 1730Z STARTED ROLLING...STARTED TO SEE GUSTS OVER 40 KTS ACROSS WEST CENTRAL MN RIGHT BEHIND THE BOUNDARY...SO LEFT BIG GUSTS IN PLACE. STILL EXPECT A 2 OR 3 HOUR WINDOW WITH SUSTAINED WINDS 30-35 KTS WITH GUSTS 40 TO 45 KTS IMMEDIATELY BEHIND THE FRONT...BEFORE SUSTAINED SPEEDS AND GUSTS SETTLE DOWN ABOUT 10 KTS. FRONT ALSO COMING DOWN WITH MVFR CIGS BETWEEN 010 AND 020. THESE CLOUDS WILL REMAIN IN PLACE THROUGH THE AFTERNOON...BUT CLEARING IS SEEN MOVING SOUTH ACROSS NODAK THIS AFTERNOON. CURRENTLY CLOCKING THIS CLEARING MOVING SOUTH AT ABOUT 50 KTS...SO A RETURN TO VFR CONDS MAY COME ABOUT FASTER THAN CURRENTLY INDICATED. THIS TREND TO VFR CIGS IS SUPPORTED BY THE SREF...WHICH HAS MUCH OF THE MPX CWA VFR OVERNIGHT...BEFORE BRINGING ANOTHER ROUND OF MVFR CIGS IN FROM THE DAKOTAS LATE TONIGHT. AS FOR WX...THERE WILL BE TWO CHANCES FOR SNOW. FIRST WILL BE BEHIND THE COLD FRONT THIS AFTERNOON...THOUGH THIS LOOKING LESS LIKELY OUTSIDE OF CENTRAL MN. RAP SOUNDINGS SHOW POST FRONTAL CLOUD LAYER REACHING UP INTO THE SNOW GROWTH ZONE NORTH...BUT AS YOU HEAD TOWARD MSP/EAU...THE POST FRONTAL CLOUD LAYER IS FORECAST TO BE TOO WARM TO GENERATE ICE CRYSTALS...SO CUT BACK ON SNOW MENTION OUTSIDE OF CENTRAL MN. SECOND CHANCE WILL COME TONIGHT AS AN UPPER WAVE MOVES ACROSS AN ELEVATED FRONTAL BOUNDARY ACROSS SW MN. MOST OF THE SNOW LOOKS TO STAY SW OF MPX TERMINALS...THOUGH RWF LOOKS TO GET A PERIOD OF -SN IN THE MORNING. KMSP...MVFR CIGS ALREADY MOVING INTO THE NW METRO AND SHOULD BE IN AT MSP WITHIN THE FIRST HOUR. WILL START SEEING GUSTS PICK UP WITH THE ARRIVAL OF THE CLOUDS...THOUGH GUSTS NEAR 40 KTS ARE TRAILING THE CLOUDS BY A BIT...THOUGH MAY SEE STRONGER GUSTS SHOW UP A BIT EARLIER THAN 22Z. ALSO PULLED BACK ON SNOW BASED ON WARMER FORECAST CLOUD LAYER...BUT LOOKING AT IR...IS A NICE BAND OF COOLER TOPS MOVING SOUTH ACROSS CENTRAL MN AT THE MOMENT. IF THIS CAN HOLD TOGETHER...MAY NEED TO MENTION AN IFR VIS MENTION IN -SN BETWEEN 21Z AND 23Z. SREF HAS A GOOD HANDEL ON CLEARING CURRENTLY MOVING ACROSS NODAK...SO FOLLOWED IT IN BRINGING VFR CONDITION BACK IN TONIGHT. SNOW MOVING INTO SW MN LOOKS TO REMAIN WELL SW OF MSP...BUT CAN NOT RULE OUT A FLURRY OR TWO WITH MVFR CONDS MOVING BACK IN BY SUNDAY AFTERNOON. /OUTLOOK FOR KMSP/ MON...MVFR CIGS POSSIBLE EARLY. WINDS NW 10 KTS. TUE...VFR. WINDS W 5 KTS. WED...VFR. WINDS SW 5 KTS. .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR ANOKA-BENTON-BLUE EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS- FARIBAULT-FREEBORN-GOODHUE-HENNEPIN-ISANTI-KANABEC- KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE- SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD- WASECA-WASHINGTON-WATONWAN-WRIGHT-YELLOW MEDICINE. WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 11 AM CST SUNDAY FOR BENTON-DOUGLAS-ISANTI-KANABEC-MILLE LACS-MORRISON-POPE- SHERBURNE-STEARNS-STEVENS-TODD. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST SUNDAY FOR ANOKA-CHISAGO. WI...WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR BARRON-CHIPPEWA- DUNN-EAU CLAIRE-PEPIN-PIERCE-POLK-RUSK-ST. CROIX. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST SUNDAY FOR BARRON-CHIPPEWA-DUNN-POLK-RUSK-ST. CROIX. && $$ DWE/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1100 AM CST SAT JAN 19 2013 .DISCUSSION... COLD FRONT HAS REACHED ALL BUT THE SOUTHERN VALLEY AND ADJACENT PORTIONS OF WEST CENTRAL MN WHERE 16 UTC OBSERVATIONS SHOWED TEMPERATURES STILL IN THE UPPER 20S AND LOW 30S. HIGHS FOR THE DAY HAVE ALREADY OCCURRED AND WILL SEE FALLING TEMPERATURES THROUGH THE LATE MORNING AND AFTERNOON HOURS. REGIONAL RADARS SHOWING WEAK STREAMERS IN WAKE OF THE FRONT...SO ADDED CHANCE POPS THROUGH THE MID-AFTERNOON FOR POSSIBLY A DUSTING TO A TENTH OF AN INCH ACCUMULATION. REALISTICALLY...WINDS WILL MAKE MEASURING ANY NEW SNOWFALL NEARLY IMPOSSIBLE. STRONGEST WIND SO FAR HAS BEEN CONFINED TO THE HIGHER TERRAIN FROM ROLLA TO RUGBY TO HARVEY TO COOPERSTOWN WHERE GUSTS AT TIMES HAVE EXCEEDED 50 MPH. FARTHER SOUTH AND EAST...GUSTS HAVE BEEN IN THE 35 TO 45 MPH RANGE. LATEST RAP STILL SHOWING 925 HPA WINDS AT OR ABOVE 40 KTS THROUGH THE AFTERNOON...SO AS MIXED LAYER DEEPENS.. STILL EXPECT WINDS TO INCREASE FOR THE NEXT FEW HOURS BEFORE DECREASING LATER THIS AFTERNOON. SINCE THE EVENT IS STILL UNFOLDING...WILL NOT MAKE ANY CHANGES TO HIGH WIND WARNING/WIND ADVISORY HEADLINES AT THIS TIME. REDUCTIONS IN VISIBILITY AT OR BELOW A QUARTER OF A MILE ARE WIDESPREAD ACROSS PORTIONS OF THE DEVILS LAKE BASIN AND NORTHERN VALLEY. THE WORST CONDITIONS WILL CONTINUE ACROSS OPEN COUNTRY AWAY FROM CITIES AND SHELTERED AREAS. MOST VISIBILITY ISSUES ARE DUE TO BLOWING AND DRIFTING SNOW ON THE GROUND...BUT CANNOT RULE OUT RAPID WORSENING CONDITIONS IF A BRIEF SNOW STREAMER MOVES OVERHEAD. CURRENT BLIZZARD WARNING/WINTER WEATHER ADVISORY LOOKS GOOD WITH NO CHANGES PLANNED. && .AVIATION... MVFR CIGS HAVE SLIPPED SOUTH AND EAST AHEAD OF DRY PUNCH...HAVING REACHED KFAR BY MID MORNING. VENTURI EFFECT HAS SHIFTED VALLEY WINDS TO A MORE NORTHERLY DIRECTION AT INCREASED SPEEDS...WILL CONTINUE FOR A TIME BEFORE BACKING TO NORTHWEST FOR THE AFTERNOON. OTHERWISE... STILL EXPECTING LOWEST VSBY VICINITY OF KDVL LATE MORNING... AFFECTING NORTHERN VALLEY SITES BY EARLY AFTERNOON. && .PREV DISCUSSION... /ISSUED 340 AM CST SAT JAN 19 2013/ DISCUSSION...FORECAST CHALLENGE CONCERNS ONGOING HEADLINES WITH STRONG ARCTIC COLD FRONT. MODELS IN GOOD AGREEMENT AND WILL USE BLEND FOR FORECAST. VERY CHALLENGING FORECAST FOR TODAY AND WILL FOCUS DISCUSSION MAINLY TO THE VERY SHORT TERM . SURFACE LOW OVER NORTHERN VALLEY TO PROPAGATE ESE AND DEEPEN BEFORE REACHING THE GREAT LAKES THIS EVENING. ASSOCIATED STRONG ARCTIC COLD FRONT TO PLOW THROUGH FORECAST AREA TODAY. MAIN CONCERN WITH FEATURE WILL BE STRONG WINDS IN WAKE OF COLD FRONTAL PASSAGE AND POTENTIAL FOR BLIZZARD CONDITIONS AND EVENTUAL HAZARDOUS WIND CHILLS WITH FALLING TEMPERATURES. WILL SPLIT DISCUSSION TO AREAS RECEIVING PARTICULAR HEADLINES. NORTHERN VALLEY INTO DVL BASIN. CURRENT BLIZZARD WARNING LOOKING GOOD. THIS AREA HAS DEEPEST SNOW COVER AND AVAILABLE FRESH SNOW TO BLOW AROUND. CURRENT BAND OF -SN ALONG AND NORTH OF SURFACE LOW SHIFTING INTO FAR NORTHERN MN AND WILL CONTINUE INTO THE MORNING HOURS. MODEL SOUNDINGS INDICATING MIXED LAYER TO AROUND 900MB WITH 30KTS TO MIX AND SHOULD BE EFFICIENT WITH STRONG COLD ADVECTION. WHILE GROUND BLIZZARD CONDITIONS NOT EXPECTED WITHIN TOWNS HAVE EXPANDED BLIZZARD WARNING INTO GRAND FORKS AND WEST POLK COUNTIES WHERE NORTHERN PARTS OF THE COUNTY AND AREAS WEST OF VALLEY RIDGE HAVE BETTER POTENTIAL FOR GROUND BLIZZARD CONDITIONS. REMAINDER OF AREAS WEST OF VALLEY. WINDS ALOFT STRONGER AND MIXED LAYER DEEPER. LOCAL CHECKLIST INDICATING POTENTIAL FOR STRONGEST WINDS THIS AREA. TEMPERATURES HAVE BEEN MILD CURRENTLY AND IN THE PAST WEEK ALONG WITH -RA LAST WEEKEND WHICH HAS CRUSTED SNOW PRETTY WELL. A FEW SNOW SHOWERS POSSIBLE WITH FROPA HOWEVER SHOULD NOT GREATLY AFFECT VSBY. WITH POTENTIAL FOR BLOWING SLIM WILL GO WITH HIGH WIND WARNING. CENTRAL/SOUTHERN VALLEY INTO ADJACENT PORTIONS OF MN...-RA LAST WEEKEND AND WARM TEMPERATURES ALSO PUT A HEAVY CRUST ON AVAILABLE THIN SNOW COVER. WITH LITTLE IN ADDITIONAL SNOW FALL ON TOP OF CRUST THINK BLSN WILL BE MINIMAL CONFINED TO SOME MINOR RESTRICTION IN OPEN COUNTRY. SHSN AGAIN ALONG FRONT TO BE ISOLD AND NOT A GREAT IMPACT ON VSBY. MIXED LAYER ALSO NOT AS DEEP AS WEST OF VALLEY AND BOTH NAM/GFS MODEL SOUNDING INDICATING ABOUT 30KTS TO MIX WHICH AGAIN SHOULD BE PRETTY EFFICIENT WITH STRENGTH OF COLD ADVECTION. WIND DIRECTION MORE NW VS N WHICH WOULD LIMIT FAVORABLE FUNNELING DOWN VALLEY. FOR THIS DO NOT FEEL WE WILL REACH HIGH WIND CRITERIA. WITH SOME BLOWING AND EVENTUAL WIND CHILLS WITH FALLING TEMPERATURES WILL OPT FOR WINTER WX ADVISORY VS JUST WIND ADVISORY TO HEIGHTEN AWARENESS VS WIND ADVISORY. FAR SOUTHERN FA HAS BEEN THE WARMEST AND DO BELIEVE THERE WILL MINIMAL BLOWING SNOW. WITH DELAY IN COLDEST AIR TILL THIS AFTERNOON WILL JUST GO WITH WIND ADVISORY. VERY COLD AIRMASS WILL HOLD OVER FA FOR THE REMAINDER OF THE PERIOD. WILL SE AN EXTENDED PERIOD OF EITHER WIND CHILL ADVISORY/WARNING HEADLINES REMAINDER OF WEEKEND INTO AT LEAST EARLY NEXT WEEK AS TEMPERATURES LIKELY TO CLIMB ABOVE ZERO AT ANY TIME. LONG TERM (TUESDAY-FRIDAY)... NORTHWEST FLOW ALOFT WILL KEEP TEMPS BELOW NORMAL THROUGH THIS PERIOD. A BIT OF MODERATION IS POSSIBLE FOR MID-WEEK AS THE UPPER AIR PATTERN DE-AMPLIFIES WITH WEAKENING OF THE WESTERN NORTH AMERICA RIDGE. HOWEVER...RECENT MODEL RUNS HAVE TRENDED A BIT COLDER FOR MID-WEEK WITH MUCH OF THE WARMER AIR REMAINING FARTHER SOUTHWEST. THE GLOBAL MODELS ALL SUGGEST A PACIFIC SHORTWAVE TROUGH WILL LIFT ACROSS THE NORTHERN ROCKIES INTO THE NORTHERN PLAINS SOMETIME IN THE LATE WEDNESDAY THROUGH THURSDAY NIGHT TIME FRAME...WITH THE GEM/ECMWF QUICKER THAN THE GFS. THIS SYSTEM WILL BRING ANOTHER CHANCE FOR A BIT OF SNOW TO THE AREA...BUT CONFIDENCE IN THE TIMING AND PLACEMENT IS LOW...GIVEN THE UNCERTAINTY IN THE EVOLUTION OF THE UPPER SYSTEM AND ASSOCIATED SFC LOW. BEHIND THE SYSTEM...COLDER TEMPS ARE EXPECTED ONCE AGAIN AS THE NORTHWEST FLOW AMPLIFIES. AVIATION... MVFR/IFR CIGS CONFINED TO FAR NORTHERN AREAS IN AREA OF -SN. REMAINDER OF FA VFR. EXPECT CIGS TO LOWER THIS AFTERNOON IN WAKE OF STRONG COLD FRONT. LOWEST VSBY EXPECTED ACROSS DVL BASIN INTO NORTHERN VALLEY WITH GROUND BLIZZARD CONDITIONS. WINDS WILL INCREASE SIGNIFICANTLY DURING THE MORNING FROM NW-SE. EXPECT WINDS OF 25-40MPH WITH HIGHER GUSTS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ030- 039. WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ052-053. BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR NDZ006>008- 014>016-024-026-027-054. HIGH WIND WARNING UNTIL 9 PM CST THIS EVENING FOR NDZ028-029-038- 049. MN...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ002- 003-005-008-013>015-022-027-028. WIND ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ029>032-040. BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR MNZ001-004-007. && $$ ROGERS/VOELKER/WJB
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
443 PM CST SAT JAN 19 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND SUNDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG SHORTWAVE DIVING SE OVER NORTHERN MINNESOTA...WHICH IS DRIVING A SURFACE LOW OVER WESTERN LAKE SUPERIOR. ARCTIC COLD FRONT EXTENDS WESTWARD FROM THIS LOW OVER CENTRAL MINNESOTA AND NORTHERN SOUTH DAKOTA. RETURNS ON RADAR OVER WESTERN WISCONSIN MAY NOT BE HITTING THE GROUND...BUT THERE IS SCATTERED SNOW SHOWERS OCCURRING ALONG THE ARCTIC FRONT AND JUST AHEAD OF THE SHORTWAVE...WHICH ARE DROPPING VISIBILITIES TO AROUND A MILE AT TIMES. WINDS ARE ALSO RAPIDLY INCREASING BEHIND THE FRONT...WITH SOME WIDELY SCATTERED REPORTS JUST HIGHER THAN 40 KTS. TEMPERATURES BEHIND THE FRONT ARE FALLING QUICKLY INTO THE SINGLE DIGITS ABOVE ZERO...WHILE READINGS ARE IN THE UPPER 30S TO LOWER 40S ACROSS NORTHERN WISCONSIN. WITH THE PASSAGE OF THE ARCTIC FRONT THIS EVENING...TEMPERATURE AND WIND HEADLINES ARE THE MAIN FORECAST CONCERNS. TONIGHT...THE STRONG SHORTWAVE WILL PUSH THE ARCTIC COLD FRONT RAPIDLY SOUTHEAST ACROSS NORTH-CENTRAL WISCONSIN LATER THIS AFTERNOON...AND NORTHEAST WISCONSIN EARLY THIS EVENING. DESPITE STRONG MID AND UPPER LEVEL FORCING IN THE FORM OF -DIVQ AND DIVERGENCE AHEAD OF THE WAVE...MID-LEVELS STRUGGLE TO SATURATE. SO THINK WILL SEE NOT MUCH MORE THAN A SCT LINE OF SNOW SHOWERS JUST AHEAD OF THE SHORTWAVE...WHICH WILL PROVIDE A BRIEF BURST OF SNOW AND REDUCE VISIBILITIES...BUT NOT MUCH IN THE WAY OF ACCUMS. SO WILL KEEP POPS IN THE LOW CHANCE RANGE OVER NE WISCONSIN FOR EARLY THIS EVENING WITH THE FRONTAL PASSAGE. CLOUDS EXTEND NORTH ACROSS MINNESOTA TO THE CANADIAN BORDER WHERE SNOW SHOWERS CONTINUE TO FALL UNDER A LOW OVERCAST. SO THINK SNOW SHOWERS WILL FALL OVER NORTH-CENTRAL WISCONSIN FOR MUCH OF THE EVENING. BEHIND THE FRONT BY LATE IN THE EVENING...LOW LEVEL WINDS WILL SHIFT TO THE NORTHWEST WITH GOOD TRAJECTORIES FOR LAKE EFFECT SNOW ACCUMULATIONS. HOWEVER...850MB TEMPS WILL BE PLUMMETING INTO THE LOWER 20S BELOW ZERO WHICH IS GETTING TOO COLD FOR GOOD DENDRITIC SNOW GROWTH. AS A RESULT...FLAKES WILL BE SMALL AND ACCUMS SHOULD BE HELD IN CHECK...AND WILL CONTINUE TO GO WITH 1-3 INCH AMOUNTS TONIGHT IN THE SNOW BELT OF N-C WISCONSIN. LITTLE TO NO ACCUM ELSEWHERE. BIGGER IMPACTS WILL LIKELY BE WIND RELATED. STRONG DESCENT IMMEDIATELY BEHIND THE FRONT IN A REGION OF STRONG COLD ADVECTION...STEEPENING LOW LEVEL LAPSE RATES...AND GOOD ISALLABARIC PUSH WILL CREATE STRONG GUSTY WEST TO NORTHWEST WINDS THAT SHOULD APPROACH OR JUST EXCEED WIND ADVISORY CRITERIA LATE THIS AFTERNOON AND THROUGH THE EVENING. STRONGEST WINDS IN THE MIXED LAYER OF 45-50KTS ARE PROGGED TO OCCUR OVER CENTRAL AND EAST-CENTRAL WISCONSIN WHERE THE CURRENT WIND ADVISORY RESIDES...SO PLACEMENT OF HEADLINES LOOK GOOD. THE GUSTY WINDS SEEM TO BE RUNNING AN HOUR OR TWO LATE...AND WILL LIKELY HAVE TO WAIT UNTIL THE COLDER AIR ALOFT ARRIVES TO STEEPEN THE LOW LEVEL LAPSE RATES FOR THE GUSTY WINDS TO OCCUR...LIKELY IN THE 22-02Z TIME PERIOD. WILL KEEP HEADLINE TIMING STATUS QUO. THE STRONG PRESSURE RISES SHIFT TO THE EAST BY MIDNIGHT...AND WIND GUSTS SHOULD BE SUBSIDING BY THIS TIME. AS A RESULT...STILL THINK THE EVENING OR MIDNIGHT CREW WILL BE ABLE TO END WIND HEADLINES EARLY. THE COMBO OF GUSTY NW WINDS AND INCOMING ARCTIC AIR WILL CREATE WIND CHILL READINGS OF 20-25 DEGREES BELOW ZERO OVER CENTRAL AND NORTH-CENTRAL WISCONSIN LATE TONIGHT. SUNDAY...ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE REGION ON SUNDAY. NORTHWEST WINDS WILL CONTINUE TO PRODUCE LAKE EFFECT SNOW SHOWERS IN THE SNOW BELTS...BUT WINDS DO BACK A BIT SO SNOW SHOWERS SHOULD BE GRADUALLY DIMINISHING OVER THE COURSE OF THE MORNING. AIR WILL REMAIN TOO COLD FOR DENDRITIC SNOW GROWTH SO NOT EXPECTING MUCH ACCUMS. OTHERWISE...STEEP LOW LEVEL LAPSE RATES AND FLOW OFF LAKE SUPERIOR SHOULD KEEP SKIES PARTLY TO MOSTLY CLOUDY. TEMPS IN THE SINGLE DIGITS TO LOWER TEENS. .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. DURATION OF THE ARCTIC BLAST OF AIR THIS WEEK ALONG WITH LIKELY ADDITIONAL WIND CHILL HEADLINES WILL BE THE PRIMARY ISSUE FOR THE FIRST HALF OF THE NEW WEEK. ANOTHER CLIPPER SYSTEM IS PROGGED TO DROP INTO THE REGION AROUND THURSDAY FOLLOWED WITH A REINFORCING BUT MILDER AND PERHAPS BRIEFER SHOT OF ARCTIC AIR. SOME MDM RANGE MODELS ARE INDICATING A MODERATING TREND LATER NEXT WEEKEND. ADDITIONAL WIND CHILL HEADLINES WILL LIKELY BE POSTED LATER THIS WEEKEND AS THE SATURDAY NIGHT HEADLINES EXPIRE. FORECAST TEMPS SUGGEST THE COLDEST AIR ARRIVES LATER MONDAY WITH SOME CURRENT VALUES APPROACHING WIND CHILL WARNING CRITERIA MONDAY NIGHT. TYPICAL WITH THE VERY COLD PATTERNS...MODELS LIKELY OVERDOING THE COVERAGE OF CLOUDS. WILL TONE DOWN CLOUDS OVER MOST LOCATIONS EXCEPT FOR AREAS JUST DOWNSTREAM FROM LAKE SUPERIOR. LAKE EFFECT SNOWS EXPECTED OVER FAR NORTH CENTRAL WISCONSIN WITH THE COLD AIR INTRUSION. BUT APPEARS TO BE LIMITED AT THIS TIME DUE TO THE DRY AIR MASS...FALLING INVERSION HEIGHTS...AND A BIT TOO WESTERLY WIND DIRECTION. TEMPS TO MODERATE TO NEAR SEASONAL LEVELS LATER THIS WEEK WITH A CLIPPER SYSTEM DROPPING SOUTH INTO THE NORTHERN AND CENTRAL PLAINS THURSDAY BEFORE PHASING WITH SOME SOUTHERN STREAM ENERGY THURSDAY NIGHT. GFS IS INDICATING A POSSIBLE ADVISORY SNOW OVER THE SOUTH HALF OR THIRD OF THE STATE THURSDAY NIGHT WITH THIS PHASED SYSTEM. WILL GLANCE AT THE ECMWF THIS AFTERNOON TOO SEE IF A SIMILAR TREND IN ORDER TO MAKE ANY ADJUSTMENTS...BUT GOING FORECAST THAT FAR OUT REASONABLE. && .AVIATION...FOR 00Z TAF ISSUANCE. ARCTIC FRONT SURGING SE ACRS THE AREA. WL SEE A PERIOD OF STG WINDS AND SOME MVFR CIGS AND VSBYS THIS EVENING. BRIEF IFR CONDITONS POSSIBLE. NOT REALLY THAT MUCH SNOW TO BLOW ARND IN THE AREA...SO EXPECT CONDITIONS TO IMPROVE BACK TO VFR BY LATE TNGT. THE EXCEPTION MAY BE IN THE FAR N /RHI/ WHERE CLDS OFF LAKE SUPERIOR WL CONT TO STREAM SE. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR WIZ038>040-048>050. WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ030-031-035>037- 045. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR WIZ005-010-011-018-019-030-035-036. WIND ADVISORY UNTIL 6 AM CST SUNDAY FOR WIZ022. && $$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
315 PM CST SAT JAN 19 2013 .SHORT TERM... TONIGHT - CONFIDENCE...MEDIUM STRENGTHENING LOW PRESSURE CONTINUES TO SHIFT EAST FROM NEAR LAKE SUPERIOR. NICE POCKET OF PRESSURE DRIVING SOUTHEAST FROM THE DAKOTAS. THE RUC IS BEHIND SCHEDULE A BIT ON THIS...BUT HAS A A PRESSURE RISE MAX OVER THE CWA AT 6Z...BUT MAY END UP BEING MORE AROUND 3Z. LEADING EDGE OF ARCTIC FRONT DRIVING SE FROM CENTRAL MN. FRONT EXPECTED TO CLEAR THE SOUTHEAST BY 3Z. BUFKIT SOUNDINGS SHOW FAIRLY DEEP POST-FRONTAL MIXING AND STRONG SUBSIDENCE FROM LATER THIS EVENING INTO THE OVERNIGHT WITH WIND ADVISORY CRITERIA STILL LIKELY. IN FACT RAP SOUNDINGS VERY IMPRESSIVE ACTUALLY SHOWING BORDERLINE WARNING FOR A TIME. RUC PROGGED 3 HOUR PRESSURE RISE OF 4-5 MB SLIDING ACROSS LATER COMBINED WITH 50 KNOT 850 WIND MAX SUGGESTS THIS IDEA. AT THIS POINT WE ARE LOOKING AT A HIGH END ADVISORY/LOW END WARNING. WILL RETAIN THE ADVISORY AT THIS POINT BUT WOULD NOT BE SURPRISED TO SEE A FEW GUSTS EXCEED THE WARNING THRESHOLD. GUIDANCE NUMBERS STILL SUPPORT SINGLE DIGIT LOWS FOR MUCH OF CWA. PREFER THE DRIER LOOK THE NAM/HPC VERSUS GFS/ECMWF WITH RESPECT TO QPF IN THE COLD ADVECTION REGIME. STRATUS POTENTIAL THERE GIVEN MODEL AGREEMENT IN LOW LEVEL RH PROGS. WILL NOT MENTION FLURRIES AT THIS TIME WITH VERY LITTLE REPORTS UPSTREAM THOUGH FLOW WILL BE CYCLONIC BUT LOW LEVELS TO BECOME DOMINATED BY SUBSIDENCE. GIVEN THE SLOWER ARRIVAL OF THE FRONT...PUSHED EASTERN WIND ADVISORY AHEAD AN HOUR. KEPT THE WEST AS IS TO BLEND WITH NEIGHBORS. SUNDAY - CONFIDENCE...MEDIUM ARCTIC AIR-MASS IN PLACE. 925 TEMPS AVERAGING -14 TO -17C SUGGEST TEMPS MODIFYING INTO THE TEENS WHICH SEEMS REASONABLE WITH ABSENCE OF SNOW-COVER. ELONGATED SHORTWAVE DROPS ACROSS THE AREA. NOT OVERLY IMPRESSED WITH THIS FEATURE. QPF PROGS TREND THIS FURTHER WEST OR SOUTHWEST OF THE CWA. FOCUS APPEARS WEST CLOSER TO MAX IN 850-700 MILLIBAR Q-VECTOR CONVERGENCE. MOISTURE LOOKS LIMITED. ADDED SOME FLURRIES IN THE SOUTHWEST IN THE AFTERNOON TO MATCH UP WITH KDVN AND KARX...BUT EVEN NEW 12Z ECMWF HAS TRENDED FURTHER SOUTHWEST THIS FEATURE. .LONG TERM... .SUNDAY NIGHT THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM. AN IMPULSE/VORTICITY MAX PROGGED BY MODELS TO SLIDE SOUTHEAST FROM DAKOTAS TO ILLINOIS SUNDAY NIGHT. HOWEVER...MOSTLY CHANNELED VORTICITY WITH THIS FEATURE. MODEL SOUNDINGS SUNDAY EVENING SUGGEST SOME FLURRIES AT BEST....WILL BLEND IN WITH NEIGHBORS ON THE FLURRIES SUNDAY EVENING. BASIC COLD DRY NORTHWEST FLOW ALOFT MONDAY INTO TUESDAY NIGHT. CORE OF COLDEST AIR AT 850 MB WILL ARRIVE IN WISCONSIN ON MONDAY WITH -24C TO -26...SETTING UP THE COLDEST NIGHT OF THE WINTER SEASON FOR MONDAY NIGHT INTO EARLY TUESDAY MORNING. PROGGED WIND CHILL VALUES OF -20C TO -25C FOR MONDAY NIGHT UNTIL ABOUT 10 OR 11 AM CST TUESDAY FOR SOUTHERN WISCONSIN WILL REQUIRE A WIND CHILL ADVISORY TO BE ISSUED ON LATER SHIFTS. THIS ASSUMES FORECAST PANS OUT. .WEDNESDAY AND WEDNESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM. SURFACE RIDGE WILL EXTEND FROM DAKOTAS TO THE TENNESSEE AREA...SO QUIET AT THIS TIME. BOTH GFS AND ECMWF MODERATE 850 MB TEMPERATURES TO -18C TO -20C BY 6 AM WED...SO SOMEWHAT WARMER SURFACE TEMPS EXPECTED ON WEDNESDAY. HOWEVER...ECMWF BRINGS ANOTHER PUSH OF COLD AIR DOWN INTO SOUTHERN WISCONSIN WEDNESDAY AFTERNOON. IN ANY CASE...BOTH MODELS CONTINUE MODERATION TREND LATE WEDNESDAY NIGHT. .THURSDAY AND FRIDAY...FORECAST CONFIDENCE IS LOW. ON THURSDAY...MODELS SHOW ANOTHER SHORT-WAVE TROUGH DROPPING EAST SOUTHEAST THROUGH THE WISCONSIN AREA. ASSOCIATED WARM-AIR ADVECTION AND ISENTROPIC LIFT IN MID-LEVELS QUICKLY RESULTS IN CLOUDY SKIES AND CHANCES OF SNOW BY LATE AFTERNOON...CONTINUING INTO THURSDAY NIGHT. A SECONDARY SHORT-WAVE TROUGH ROTATES SOUTH OUT OF WESTERN ONTARIO CANADA ON FRIDAY INTO GREAT LAKES REGION. THIS WILL CONTINUE THE CHANCES OF SOME LIGHT SNOW INTO FRIDAY. MEANWHILE...SURFACE LOW PRESSURE WILL MOVE NORTHEAST TO SOUTHERN OHIO BY FRIDAY MORNING PER GFS...AND IN KENTUCKY PER ECMWF. 12Z GFS RUN THIS MORNING HAS THIS LOW PRESSURE DEEPER THAN ECMWF...A FLIP-FLOP FROM 00Z RUN FRIDAY EVENING WHICH HAD ECMWF WITH THE DEEPER SOLUTION. STAY TUNED. && .AVIATION/00Z TAFS/...MAIN CONCERN WILL BE THE STRONG POST-FRONTAL WINDS THAT ARRIVE VERY LATE THIS AFTERNOON/MORE LIKELY THIS EVENING ACROSS SRN WI. NW WINDS OF 25-35 KNOTS LOOK LIKE A GOOD BET WITH SOME GUSTS OVER 40 KNOTS. LOW LEVEL RH PROGS SUGGEST A GLANCING SHOT OF STRATUS IN THE 6-12Z TIME FRAME TONIGHT IN THE COLD ADVECTION REGIME...WITH A DRIER SIGNAL IN THE 12Z-00Z TIME FRAME ON SUNDAY. GRADIENT SLACKENS FOR SUNDAY. WEAK VORT AXIS SLIDES THROUGH THOUGH MOISTURE/LIFT LACKING. A FEW FLURRIES IN PARTS OF SC WI THOUGH ALL MODELS KEEP QPF FURTHER SOUTHWEST OF THE AREA. && .MARINE...NO CHANGES TO HEADLINES AT THIS POINT. HEAVY FREEZING SPRAY AND GALE CONDITIONS LOOK VERY FAVORABLE TONIGHT AS STRONG COLD FRONT PUSHES THROUGH THIS EVENING. ONCE GALE EXPIRES...SMALL CRAFT WILL LIKELY BE NEEDED. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ046-047-056-057- 062-063-067-068. WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR WIZ051-052-058>060- 064>066-069>072. LM...HEAVY FREEZING SPRAY WARNING FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY FOR LMZ643>646. SMALL CRAFT ADVISORY UNTIL 6 PM CST THIS EVENING FOR LMZ643>646. GALE WARNING UNTIL 6 AM CST SUNDAY FOR LMZ643>646. && $$ TONIGHT/SUNDAY AND AVIATION/MARINE...COLLAR SUNDAY NIGHT THROUGH SATURDAY...KAPELA
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
218 PM CST SAT JAN 19 2013 .SHORT TERM...TONIGHT AND SUNDAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A STRONG SHORTWAVE DIVING SE OVER NORTHERN MINNESOTA...WHICH IS DRIVING A SURFACE LOW OVER WESTERN LAKE SUPERIOR. ARCTIC COLD FRONT EXTENDS WESTWARD FROM THIS LOW OVER CENTRAL MINNESOTA AND NORTHERN SOUTH DAKOTA. RETURNS ON RADAR OVER WESTERN WISCONSIN MAY NOT BE HITTING THE GROUND...BUT THERE IS SCATTERED SNOW SHOWERS OCCURRING ALONG THE ARCTIC FRONT AND JUST AHEAD OF THE SHORTWAVE...WHICH ARE DROPPING VISIBILITIES TO AROUND A MILE AT TIMES. WINDS ARE ALSO RAPIDLY INCREASING BEHIND THE FRONT...WITH SOME WIDELY SCATTERED REPORTS JUST HIGHER THAN 40 KTS. TEMPERATURES BEHIND THE FRONT ARE FALLING QUICKLY INTO THE SINGLE DIGITS ABOVE ZERO...WHILE READINGS ARE IN THE UPPER 30S TO LOWER 40S ACROSS NORTHERN WISCONSIN. WITH THE PASSAGE OF THE ARCTIC FRONT THIS EVENING...TEMPERATURE AND WIND HEADLINES ARE THE MAIN FORECAST CONCERNS. TONIGHT...THE STRONG SHORTWAVE WILL PUSH THE ARCTIC COLD FRONT RAPIDLY SOUTHEAST ACROSS NORTH-CENTRAL WISCONSIN LATER THIS AFTERNOON...AND NORTHEAST WISCONSIN EARLY THIS EVENING. DESPITE STRONG MID AND UPPER LEVEL FORCING IN THE FORM OF -DIVQ AND DIVERGENCE AHEAD OF THE WAVE...MID-LEVELS STRUGGLE TO SATURATE. SO THINK WILL SEE NOT MUCH MORE THAN A SCT LINE OF SNOW SHOWERS JUST AHEAD OF THE SHORTWAVE...WHICH WILL PROVIDE A BRIEF BURST OF SNOW AND REDUCE VISIBILITIES...BUT NOT MUCH IN THE WAY OF ACCUMS. SO WILL KEEP POPS IN THE LOW CHANCE RANGE OVER NE WISCONSIN FOR EARLY THIS EVENING WITH THE FRONTAL PASSAGE. CLOUDS EXTEND NORTH ACROSS MINNESOTA TO THE CANADIAN BORDER WHERE SNOW SHOWERS CONTINUE TO FALL UNDER A LOW OVERCAST. SO THINK SNOW SHOWERS WILL FALL OVER NORTH-CENTRAL WISCONSIN FOR MUCH OF THE EVENING. BEHIND THE FRONT BY LATE IN THE EVENING...LOW LEVEL WINDS WILL SHIFT TO THE NORTHWEST WITH GOOD TRAJECTORIES FOR LAKE EFFECT SNOW ACCUMULATIONS. HOWEVER...850MB TEMPS WILL BE PLUMMETING INTO THE LOWER 20S BELOW ZERO WHICH IS GETTING TOO COLD FOR GOOD DENDRITIC SNOW GROWTH. AS A RESULT...FLAKES WILL BE SMALL AND ACCUMS SHOULD BE HELD IN CHECK...AND WILL CONTINUE TO GO WITH 1-3 INCH AMOUNTS TONIGHT IN THE SNOW BELT OF N-C WISCONSIN. LITTLE TO NO ACCUM ELSEWHERE. BIGGER IMPACTS WILL LIKELY BE WIND RELATED. STRONG DESCENT IMMEDIATELY BEHIND THE FRONT IN A REGION OF STRONG COLD ADVECTION...STEEPENING LOW LEVEL LAPSE RATES...AND GOOD ISALLABARIC PUSH WILL CREATE STRONG GUSTY WEST TO NORTHWEST WINDS THAT SHOULD APPROACH OR JUST EXCEED WIND ADVISORY CRITERIA LATE THIS AFTERNOON AND THROUGH THE EVENING. STRONGEST WINDS IN THE MIXED LAYER OF 45-50KTS ARE PROGGED TO OCCUR OVER CENTRAL AND EAST-CENTRAL WISCONSIN WHERE THE CURRENT WIND ADVISORY RESIDES...SO PLACEMENT OF HEADLINES LOOK GOOD. THE GUSTY WINDS SEEM TO BE RUNNING AN HOUR OR TWO LATE...AND WILL LIKELY HAVE TO WAIT UNTIL THE COLDER AIR ALOFT ARRIVES TO STEEPEN THE LOW LEVEL LAPSE RATES FOR THE GUSTY WINDS TO OCCUR...LIKELY IN THE 22-02Z TIME PERIOD. WILL KEEP HEADLINE TIMING STATUS QUO. THE STRONG PRESSURE RISES SHIFT TO THE EAST BY MIDNIGHT...AND WIND GUSTS SHOULD BE SUBSIDING BY THIS TIME. AS A RESULT...STILL THINK THE EVENING OR MIDNIGHT CREW WILL BE ABLE TO END WIND HEADLINES EARLY. THE COMBO OF GUSTY NW WINDS AND INCOMING ARCTIC AIR WILL CREATE WIND CHILL READINGS OF 20-25 DEGREES BELOW ZERO OVER CENTRAL AND NORTH-CENTRAL WISCONSIN LATE TONIGHT. SUNDAY...ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE REGION ON SUNDAY. NORTHWEST WINDS WILL CONTINUE TO PRODUCE LAKE EFFECT SNOW SHOWERS IN THE SNOW BELTS...BUT WINDS DO BACK A BIT SO SNOW SHOWERS SHOULD BE GRADUALLY DIMINISHING OVER THE COURSE OF THE MORNING. AIR WILL REMAIN TOO COLD FOR DENDRITIC SNOW GROWTH SO NOT EXPECTING MUCH ACCUMS. OTHERWISE...STEEP LOW LEVEL LAPSE RATES AND FLOW OFF LAKE SUPERIOR SHOULD KEEP SKIES PARTLY TO MOSTLY CLOUDY. TEMPS IN THE SINGLE DIGITS TO LOWER TEENS. .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. DURATION OF THE ARCTIC BLAST OF AIR THIS WEEK ALONG WITH LIKELY ADDITIONAL WIND CHILL HEADLINES WILL BE THE PRIMARY ISSUE FOR THE FIRST HALF OF THE NEW WEEK. ANOTHER CLIPPER SYSTEM IS PROGGED TO DROP INTO THE REGION AROUND THURSDAY FOLLOWED WITH A REINFORCING BUT MILDER AND PERHAPS BRIEFER SHOT OF ARCTIC AIR. SOME MDM RANGE MODELS ARE INDICATING A MODERATING TREND LATER NEXT WEEKEND. ADDITIONAL WIND CHILL HEADLINES WILL LIKELY BE POSTED LATER THIS WEEKEND AS THE SATURDAY NIGHT HEADLINES EXPIRE. FORECAST TEMPS SUGGEST THE COLDEST AIR ARRIVES LATER MONDAY WITH SOME CURRENT VALUES APPROACHING WIND CHILL WARNING CRITERIA MONDAY NIGHT. TYPICAL WITH THE VERY COLD PATTERNS...MODELS LIKELY OVERDOING THE COVERAGE OF CLOUDS. WILL TONE DOWN CLOUDS OVER MOST LOCATIONS EXCEPT FOR AREAS JUST DOWNSTREAM FROM LAKE SUPERIOR. LAKE EFFECT SNOWS EXPECTED OVER FAR NORTH CENTRAL WISCONSIN WITH THE COLD AIR INTRUSION. BUT APPEARS TO BE LIMITED AT THIS TIME DUE TO THE DRY AIR MASS...FALLING INVERSION HEIGHTS...AND A BIT TOO WESTERLY WIND DIRECTION. TEMPS TO MODERATE TO NEAR SEASONAL LEVELS LATER THIS WEEK WITH A CLIPPER SYSTEM DROPPING SOUTH INTO THE NORTHERN AND CENTRAL PLAINS THURSDAY BEFORE PHASING WITH SOME SOUTHERN STREAM ENERGY THURSDAY NIGHT. GFS IS INDICATING A POSSIBLE ADVISORY SNOW OVER THE SOUTH HALF OR THIRD OF THE STATE THURSDAY NIGHT WITH THIS PHASED SYSTEM. WILL GLANCE AT THE ECMWF THIS AFTERNOON TOO SEE IF A SIMILAR TREND IN ORDER TO MAKE ANY ADJUSTMENTS...BUT GOING FORECAST THAT FAR OUT REASONABLE. && .AVIATION...WHILE LIGHT MIXED PRECIPITATION HAS EXITED NORTHEAST WISCONSIN...THE BIGGEST AVIATION HAZARDS WILL ACCOMPANY AN ARCTIC COLD FRONTAL PASSAGE LATE THIS AFTERNOON AND THIS EVENING. SCT SNOW SHOWERS ARE STILL EXPECTED TO DEVELOP ALONG THE FRONT...WITH LOCAL VSBYS BLO 1SM. IN ADDITION...STRONG WEST WINDS WILL DEVELOP BEHIND THE FRONT AS ARCTIC AIR POURS ACROSS THE STATE...WITH GUSTS TO 35 TO 40 KTS...HIGHEST ACROSS C/EC WI AND ALONG THE LAKESHORE. LAKE EFFECT SNOW SHOWERS WILL DEVELOP IN NC WI TONIGHT...AND NW WINDS WILL BE STRONG ENOUGH TO CARRY SOME SNOW INTO RHI. IMPROVING CONDITIONS WILL OCCUR AFTER MIDNIGHT IN TERMS OF DIMINISHING WINDS...SNOW SHOWERS...AND INCREASING CIGS. VFR CONDITIONS TOMORROW UNDER ARCTIC HIGH PRESSURE. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST SUNDAY FOR WIZ038>040-048>050. WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ030-031-035>037- 045. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR WIZ005-010-011-018-019-030-035-036. WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR WIZ022. && $$ MPC/TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 AM CST SAT JAN 19 2013 .SHORT TERM...TODAY THROUGH MONDAY NIGHT 947 AM CST SAT JAN 19 2013 947 AM UPDATE...FORECAST IN GENERAL REMAINS ON TRACK. POTENT SHORTWAVE WAS NOTED ON THE 15Z WATER VAPOR LOOP OVER SOUTHERN MANITOBA...WITH A 120-140 KT JET AT THE TROPOPAUSE DIGGING INTO THE DAKOTAS ON THE SOUTHWEST SIDE OF THE SHORTWAVE PER RAP ANALYSIS. DPVA AHEAD OF THE SHORTWAVE HAS RESULTED IN A DEEPENING SURFACE LOW...CURRENTLY AROUND 1002MB CENTERED OVER THE MN ARROWHEAD. TRAILING THE LOW IS AN ARCTIC COLD FRONT ALONG THE NORTH DAKOTA/SOUTH DAKOTA BORDER. SURFACE TEMPERATURES DROP FROM THE MID TO UPPER 30S FROM SOUTH DAKOTA INTO THE FORECAST AREA...INTO THE SINGLE DIGITS ABOVE ZERO OVER NORTHERN NORTH DAKOTA. WITH THE RAPID DROP IN TEMPERATURES IS A 2 MB/HR PRESSURE RISE OVER NORTH DAKOTA. THESE PRESSURE RISES AND A TIGHT PRESSURE GRADIENT BEHIND THE ARCTIC FRONT HAS RESULTED IN WINDS GUSTING 30-50 KT ACROSS NORTH DAKOTA INTO FAR NORTHWEST MN. THERE ARE ALSO SOME SNOW SHOWERS OCCURRING IMMEDIATELY BEHIND THE FRONT...AIDED BY LOW LEVEL FRONTOGENESIS. NAM/RAP/HRRR FORECASTS CONTINUE TO INDICATE THAT THE ARCTIC FRONT WILL CROSS THE FORECAST AREA BETWEEN 21-00Z...WITH WINDS AND GUSTS RAPIDLY INCREASING BEHIND THE FRONT AS INDICATED OVER NORTH DAKOTA. INTERESTING TO SEE THAT AT 00Z...THE RAP WIND GUSTS SHOW UPWARDS OF 40 KT OR SO ACROSS THE ENTIRE FORECAST AREA. NEEDLESS TO SAY...THE WIND ADVISORY LOOKS SOLID. PLUS...THE SURFACE LOW SHOULD BE ABLE TO DEEPEN A LITTLE MORE AS IT MOVES ACROSS THE WARMER LAKE SUPERIOR WATER...AND HAS THE SYNOPTIC SCALE IMPACT TO DEEPEN. THERE ARE 2 ISSUES PRIOR TO THE ARCTIC FRONT ARRIVAL...THOUGH. THE FIRST IS CLOUD COVER. FIRST BAND OF MID CLOUDS...ASSOCIATED WITH A SHORTWAVE SEEN ON WATER VAPOR STRETCHING FROM NORTHEAST NEBRASKA TO LA CROSSE...IS CLEARING OUT OF THE FORECAST AREA RIGHT NOW. ANOTHER BATCH OF MID CLOUDS HAVE DEVELOPED OVER CENTRAL MN...AHEAD OF ANOTHER WEAK SHORTWAVE. THESE CLOUDS APPEAR SLATED TO CROSS THE FORECAST AREA DURING THE NEXT FEW HOURS. HAVE INCREASED CLOUD COVER TO ACCOUNT FOR THESE. THERE STILL MAY BE ANOTHER BREAK IN CLOUDS BEFORE THE ARCTIC FRONT ARRIVES. WITH THE IN-AND-OUT PERIODS OF SUNSHINE AND 925MB TEMPS AROUND 5C PER 12Z MPX AND DVN RAOBS...CONCERNED TEMPERATURES ARE NOT HIGH ENOUGH. HRRR ACTUALLY HAS TEMPERATURES CLIMBING INTO THE LOW 50S OVER THE SOUTHERN HALF OF THE FORECAST AREA. HRRR DID VERY WELL YESTERDAY...ALBEIT WE DID HAVE FULL SUNSHINE. FOR NOW HAVE INCREASED TEMPERATURES SLIGHTLY...MAINLY SOUTH OF I-90. LASTLY...RAP AND 00Z/06Z NCEP HIRES ARW RUNS ARE IN GOOD AGREEMENT SHOWING THE BAND OF SNOW SHOWERS OVER SOUTHERN NORTH DAKOTA POST- FRONTAL DROPPING THROUGH MOST OF THE FORECAST AREA BETWEEN 18-00Z. PREVIOUS FORECAST HAD THIS COVERED WELL...JUST GAVE A LITTLE MORE TIMING AND SWITCHED TO A COVERAGE SNOW SHOWERS PHRASING SINCE THERE IS A CONVECTIVE NATURE TO THE PRECIPITATION. PREVIOUS DISCUSSION ISSUED AT 318 AM... THE MAIN FOCUS IS ON THE DRASTIC CHANGES THAT ARE ON TAP FOR TODAY AS A COLD FRONT DROPS THROUGH THE REGION. CURRENTLY...BROAD CYCLONIC FLOW ALOFT IS IN PLACE THROUGH MUCH OF CANADA AND THE US WITH THE CORE OF THE LOW CENTERED TO THE EAST OF HUDSON BAY LEAVING THE UPPER MISSISSIPPI RIVER VALLEY IN NORTHWESTERLY FLOW. DESPITE THIS...LOW LEVEL TEMPERATURES REMAIN MILD AT THE MOMENT WITH A SURFACE LOW OVER EASTERN NORTH DAKOTA AND A WARM FRONT EXTENDING TO THE EAST-SOUTHEAST ACROSS NORTHERN WISCONSIN. THIS MORNING WILL END UP BEING THE WARMEST PART OF THE DAY AS THIS SURFACE LOW TRACKS TO THE EAST TOWARD THE UP OF MICHIGAN. THIS FEATURE WILL BRING A COLD FRONT THROUGH THE REGION EARLY THIS AFTERNOON WITH WINDS SHIFTING TO THE NORTHWEST AND BECOMING STRONG POST-FROPA. NOT A WHOLE LOT OF CHANGES TO THE GOING WIND FORECAST WITH A TIGHTENING SURFACE PRESSURE GRADIENT...STRONG LOW LEVEL COLD AIR ADVECTION AND 3HR PRESSURE RISES OF 6-8MB SHOULD ALL LEAD TO STRONG AND GUSTY WINDS FOR A 6 TO 9 HOUR PERIOD LATE THIS AFTERNOON AND EVENING. SUBSIDENT AIR SHOULD HELP TO MIX DOWN SOME HIGHER GUSTS IN THE 45-50MPH RANGE...PARTICULARLY IN THE HIGHER ELEVATIONS IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA. BASED ON ALL THIS...THE WIND ADVISORY STILL LOOKS GOOD FOR THE REGION STARTING MID AFTERNOON AND ENDING AROUND MIDNIGHT AS THE WINDS DIMINISH. ANOTHER FEATURE WITH THIS FRONT IS THE BRIEF SHOT OF SNOW THAT WILL COME WITH IT. THE 19.00Z NAM AND MESO-MODELS SHOW A BAND OF SNOW FORMING OUT AHEAD OF THE COLD FRONT WHERE THE OVERALL FORCING IS A LITTLE STRONGER ACROSS SOUTHEAST MINNESOTA AND NORTH CENTRAL WISCONSIN. THIS WILL LEAD TO A SHORT PERIOD...LIKELY LESS THAN AN HOUR...OF SNOW WHICH COULD BRIEFLY BE HEAVY. THIS COULD LEAD TO A BRIEF DUSTING OF AROUND A HALF INCH OF SNOW AS IT COMES THROUGH. KEPT SOME FLURRIES THROUGH THE NIGHT ACROSS MUCH OF THE REGION DUE TO THE LOW LEVEL SATURATED LAYER BEING IN THE ICE LAYER OF -8C TO -20C...THOUGH THEY MAY NOT OCCUR IF THE SUBSIDENCE IS TOO STRONG AND CLEARS THINGS OUT. ALTHOUGH WINDS WILL BE ON THE DECREASE AFTER MIDNIGHT...THEY WILL STILL BE IN THE 10-20MPH RANGE AS THE COLDER AIR MOVES INTO THE REGION. BASED ON THE TEMPERATURE/WIND FORECAST...THERE COULD BE SOME -20F TO -25F WIND CHILLS THAT OCCUR ACROSS PORTIONS OF SOUTHEAST MINNESOTA AND NORTH CENTRAL WISCONSIN. THIS MAY WARRANT THE NEED FOR A WIND CHILL ADVISORY ONCE THE WIND ADVISORY ENDS. MAY STILL GO FOR ONE THIS MORNING...BUT AM STILL WORKING ON THE COLLABORATION WITH NEIGHBORING OFFICES AT THE MOMENT ON WHETHER TO GO FOR IT NOW OR LATER TODAY. BEYOND THIS ITS ALL ABOUT HOW COLD TEMPERATURES WILL GET WITH LITTLE TO NO SNOW PACK OUT THERE. A WEAKENING MID LEVEL TROUGH THAT HAS LITTLE LOW LEVEL SUPPORT WILL MOVE THROUGH ON SUNDAY AND COULD PROVIDE ANOTHER DUSTING OF SNOW...THOUGH CONFIDENCE IS NOT VERY HIGH ON THIS WITH THE WEAK MID LEVEL LIFT. HAD THE SNOW PACK NOT ERODED AWAY LAST WEEK...OUR TEMPERATURES WOULD LIKELY BE ABOUT 10 DEGREES COLDER THAN WHAT IS BEING FORECAST. DESPITE THIS...THE GUIDANCE ALL REMAINS IN GOOD AGREEMENT OF HAVING SUB-ZERO TEMPERATURES IN PLACE TO START NEXT WEEK. WIND CHILL ADVISORIES WILL DEFINITELY BE NEEDED FROM MONDAY MORNING THROUGH TUESDAY MORNING WITH WIND CHILLS IN THE -20F TO -30F RANGE. .LONG TERM...TUESDAY THROUGH FRIDAY 318 AM CST SAT JAN 19 2013 THE COLD AIR MASS APPEARS TO REMAIN IN PLACE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY THROUGH THE REST OF THE WEEK THOUGH IT DOES MODERATE SOME GOING INTO WEDNESDAY AND BEYOND AS THE RIDGE AXIS MOVES THROUGH AND THE CORE OF COLD LOW LEVEL AIR SHIFTS TO THE EAST. THERE ARE SOME HINTS THAT A SYSTEM WILL DROP DOWN THROUGH THE NORTHWEST FLOW ALOFT TUESDAY INTO TUESDAY NIGHT WHICH COULD BRING SOME SNOW ALONG WITH IT. THE 19.00Z GFS IS THE ONLY MODEL SHOWING THIS SNOW REACHING THE FORECAST AREA WITH THE 19.00Z ECMWF PLACING THE SURFACE RIDGE RIGHT ALONG THE MISSISSIPPI RIVER. SHOULD THE GFS PAN OUT...THERE COULD BE SOME HIGH RATIO SNOW THAT OCCURS WITH 19.00Z BUFKIT SOUNDINGS SHOWING A DEEP DENDRITIC GROWTH ZONE FROM THE SURFACE ON UP TO 700MB. THE BEST CHANCES FOR AN ACCUMULATING SNOW IS WITH A SYSTEM THAT MAY COME IN ON THURSDAY OR FRIDAY. THE 19.00Z GFS IS SLOW WITH THIS SYSTEM AND BRINGS IT IN THURSDAY NIGHT INTO FRIDAY WHILE THE 19.00Z ECMWF HAS IT THROUGH BY THURSDAY. THE 19.00Z GFS BUFKIT SOUNDINGS ARE EVEN DEEPER WITH THE DENDRITIC GROWTH ZONE AND LIFT WITH THIS SYSTEM...WHICH COULD AGAIN LEAD TO A HIGH SNOW TO LIQUID RATIO SNOW. TRENDED LOWER ON TEMPERATURES ON THURSDAY WITH GUIDANCE SHOWING THIS SYSTEM TRENDING A BIT FURTHER TO THE SOUTH. && .AVIATION...THROUGH 18Z SUNDAY 1135 AM CST SAT JAN 19 2013 ARCTIC FRONT CONTINUES ITS MARCH TOWARDS THE TAF SITES AND AS OF 17Z STRETCHED FROM NEAR ABERDEEN SD TO DULUTH MN. AHEAD OF THE FRONT...WINDS ARE TURNING WESTERLY AND SHOULD START GUSTING SHORTLY TO 25 KT AT KRST DUE TO DAYTIME MIXING. KLSE IS A LITTLE MORE PROTECTED BY THE VALLEY...BUT STILL BY 20Z ANTICIPATING GUSTS TO DEVELOP THERE. VFR CONDITIONS ANTICIPATED UNTIL THE ARCTIC FRONT ARRIVES DUE TO DRY LOW LEVEL AIR IN PLACE. ARCTIC FRONT SHOULD REACH KRST AROUND 21Z AND KLSE AROUND 22Z. IMMEDIATELY IN ITS WAKE...WINDS VEER TOWARDS THE NORTHWEST AND RAPIDLY INCREASE. EXPECTING BOTH TAF SITES TO SEE SUSTAINED WINDS OF 25-30 KT WITH GUSTS OF 40-45 KT WHICH WILL LAST THROUGH MUCH OF THE EVENING. THE STRONG WINDS ARE A RESULT OF ARCTIC AIR FLOWING...PRESSURES RISING RAPIDLY AND THE LOW PRESSURE AREA RESPONSIBLE FOR A TIGHT PRESSURE GRADIENT OVER THE TAF SITES DEEPENING AS IT CROSSES LAKE SUPERIOR. ALONG WITH THE FRONT WILL COME A BAND OF MVFR STRATUS WITH SOME FLURRIES/SNOW SHOWERS. VISIBILITIES MAY DROP TO IFR VERY BRIEFLY...BUT MVFR SEEMS MORE LIKELY SINCE THE SNOW SHOWER COVERAGE SHOULD BE SCATTERED AT BEST. KEPT THE TEMPO GROUP OF MVFR VISIBILITY TIL 00Z WHEN SNOW SHOWERS ARE MOST LIKELY. UPSTREAM...CLEARING CAN BE SEEN DROPPING INTO NORTHERN NORTH DAKOTA. ANTICIPATING THIS TO REACH THE TAF SITES AROUND 06Z TO HELP SCATTER OUT THE MVFR CLOUD DECK...LEADING TO VFR CONDITIONS AFTERWARDS THROUGH 18Z SUNDAY. PLAN ON WINDS TO GRADUALLY DIMINISH AS WELL BETWEEN 06-18Z SUNDAY...STAYING THE STRONGEST AT KLSE BEING CLOSER TO THE SURFACE LOW AND FARTHEST AWAY FROM ARCTIC HIGH PRESSURE BUILDING INTO WESTERN MINNESOTA. && .ARX WATCHES/WARNINGS/ADVISORIES... 551 AM CST SAT JAN 19 2013 WI...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR WIZ017-029-032>034-041>044-053>055-061. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR WIZ017-029. MN...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR MNZ079-086>088-094>096. IA...WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR IAZ008>011-018-019-029-030. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1130 AM CST SAT JAN 19 2013 UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE .UPDATE...THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN AREA OF MIXED PRECIPITATION OVER NE WISCONSIN LATE THIS MORNING. THIS PRECIPITATION SHOULD EXIT BY AROUND MIDDAY...BUT COULD STILL LEAD TO SLICK ROADWAYS OVER DOOR COUNTY WHERE TEMPERATURES ARE CURRENTLY IN THE UPPER 20S. LOOKING AHEAD...A STRONG SHORTWAVE AND ARCTIC COLD FRONT ARE NOW MOVING QUICKLY EAST OVER NORTHERN MINNESOTA. BOTH THE 12Z NAM AND RUC SHOW THESE FEATURES REACHING NORTH-CENTRAL AND CENTRAL WISCONSIN AROUND 20-21Z AND NORTHEAST WISCONSIN BY AROUND 00Z. UPSTREAM OBS OVER NORTH DAKOTA AND NORTHERN MINNESOTA SHOW OBS IN THE 1-3SM RANGE...AND SUPPORT GOING WITH LIKELY SNOW SHOWERS OVER N-C WISCONSIN LATE THIS AFTERNOON. ALSO HAVE OBSERVED SEVERAL WIND GUSTS IN THE UPPER 30S TO LOWER 40S KTS BEHIND THE FRONT...WHERE A STRONG ISALLOBARIC COMPONENT IS LEADING TO HIGHER GUSTS. SINCE THE COLDER AIR BEHIND THE FRONT IS NOT PROGGED TO ARRIVE OVER THE FOX VALLEY AND LAKESHORE UNTIL 00Z...HAVE DELAYED THE WIND ADVISORY HEADLINES BY A FEW HOURS THERE. THE BEST PERIOD OF WIND IS DUE TO ARRIVE LATE THIS AFTERNOON THROUGH LATE THIS EVENING WHEN THE STRONGEST DESCENDING MOTION AND ISALLOBARIC PUSH ARRIVE. THINK THE ADVISORY ENDING TIME IS A BIT TOO LONG...BUT WILL RE-EXAMINE THAT LATER. MPC && .PREV DISCUSSION...ISSUED AT 625 AM CST SAT JAN 19 2013. SHORT TERM...TODAY THROUGH SUNDAY...PCPN TRENDS...STRONG WINDS... FALLING TEMPERATURES AND ASSOCIATED WIND ADVISORY/WIND CHILL/MARINE HEADLINES ARE THE MAIN FCST CONCERNS. CLIPPER LOW OVER NE ND/NW MN WILL TRACK THROUGH THE UPPER PENINSULA OF MICHIGAN TODAY...AND DRAG AN ARCTIC COLD FRONT THROUGH THE FCST AREA THIS AFTERNOON. SCT SNOW SHOWERS SEEN OVER THER MN ARROWHEAD AND FAR NW WI SHOULD BRUSH THROUGH NORTHERN WI THIS MORNING...AND ADDITIONAL SNOW SHOWERS WILL ACCOMPANY THE COLD FRONT THIS AFTERNOON. ALTHOUGH MOISTURE IS LACKING WITH THIS SYSTEM...VERY STG DYNAMICS ASSOC WITH A STG S/W TROF...THE LFQ OF AN UPPER LEVEL JET...DEEP MID-LEVEL FRONTOGENTIC FORCING AND STEEP 850-700 MB LAPSE RATES WILL HELP GENERATE SCT MODERATE SNOW SHOWERS ALONG THE FRONT THIS AFTERNOON. THIS COULD END UP BEING A HISA (HIGH IMPACT SUB-ADVISORY) EVENT...AS LOCALLY POOR VISIBILITIES WILL LIKELY OCCUR...AND WET ROADS WILL QUICKLY FREEZE AS TEMPERATURES PLUMMET BEHIND THE FRONT LATE THIS AFTERNOON. WILL MENTION THIS POSSIBILITY IN THE HWO...AND ADD AN EXTRA PARAGRAPH ABOUT IT IN THE WIND ADVISORY STATEMENT. THE DAY SHIFT CAN ISSUE AN SPS IF THE SNOW SHOWERS AND TRAVEL CONCERNS DEVELOP AS EXPECTED. HAVE MAINTAINED LIKELY POPS ACROSS NC WI FOR THIS AFTERNOON...WHERE MOST PLACES SHOULD PICK UP AN INCH OR SO OF SNOW THIS AFTERNOON. LOCALLY HIGHER AMOUNTS ARE POSSIBLE IN VILAS COUNTY. PCPN TRENDS WILL TRANSITION TO MORE OF A TYPICAL NW FLOW LAKE EFFECT PATTERN TONIGHT INTO SUNDAY. THE SETUP IS NEVER PERFECT FOR BIG ACCUMS...AS THE WIND TRAJECTORY IS BIT TOO WESTERLY AT TIMES...STG SUBSIDENCE OCCURS AT TIMES...AND LLVL TEMPS BECOME TOO COLD FOR DENDRITES BY MID-EVENING TONIGHT. PLAN TO MENTION ADDITIONAL ACCUMS OF 1 TO 3 INCHES IN VILAS COUNTY TONIGHT AND ANOTHER INCH ON SUNDAY. STG CAA AND SUBSIDENCE IN THE WAKE OF THE FRONT...COMBINED WITH 925 MB WINDS 40-45 KTS/850 MB WINDS OF 45-55 KT...AND STEEP LLVL LAPSE RATES...SHOULD RESULT IN WIND GUSTS TO 45 TO 50 MPH ACROSS MOST OF C/EC WI AND THE LAKESHORE LATE THIS AFTERNOON AND TONIGHT. HAVE ISSUED A WIND ADVISORY FOR THIS AREA. THE WINDS WILL SUBSIDE A BIT OVERNIGHT...BUT THE COMBINATION OF WIND/TEMPS WILL PRODUCE WIND CHILLS AS COLD AS -25 OVER MUCH OF NC/C WI OVERNIGHT INTO SUNDAY MORNING. HAVE ISSUED A WIND CHILL ADVISORY FOR THAT AREA. LONG TERM...SUNDAY NGT THRU NEXT FRI. THE MAIN STORY FOR THE FIRST PART OF THE EXTENDED FCST TO BE THE ARCTIC BLAST WHICH WL SETTLE OVER THE REGION WITH THE COLDEST AIR THIS WINTER SEASON. NOT UNTIL THE WRN CONUS UPR RDG BREAKS DOWN AT MID-WEEK WL THE ARCTIC AIR BEGIN TO LEAVE WI...TO QUICKLY BE FOLLOWED BY A RELATIVELY STRONG/FAST-MOVING SHORTWAVE TROF ACROSS THE NRN TIER OF STATES. THIS SYSTEM WOULD IMPACT NE WI THU-THU NGT AND BRING THE NEXT CHC FOR MEASURABLE SNOW. TEMPS BY LATE IN THE WORK WEEK SHOULD AT LEAST APPROACH NORMAL ALTHO ANOTHER COOL DOWN IS HINTED AT BY THE MDLS FOR NEXT WEEKEND. ARCTIC AIR WL CONT TO POUR INTO THE GREAT LAKES SUNDAY NGT WITH 8H TEMPS OVER NW WI APPROACHING -30C. THE PRESSURE GRADIENT IS STILL FAIRLY TIGHT BETWEEN THE DEPARTED CLIPPER OVER SE CANADA AND STRONG HI PRES OVER THE NRN/CNTRL PLAINS. EXPECT TO SEE WIND CHILL HEADLINES TO BE ISSUED WITH MIN TEMPS RANGING FROM THE MID-TEENS BELOW ZERO N-CNTRL TO AROUND ZERO LAKESIDE...COUPLED WITH W-NW WINDS AROUND 10 MPH...TO SEND WIND CHILLS INTO THE -20 TO -32 DEGREE RANGE. THESE W-NW WINDS ARE NOT A FAVORABLE TRAJ FOR HEAVY LAKE EFFECT SNOW SHWRS OVER VILAS CNTY...HOWEVER ANTICIPATE SEEING AT LEAST SCT SNOW SHWR ACTIVITY REACH THE FAVORED SNOWBELT AREAS OF THE CNTY WITH PERHAPS UP TO AN INCH OF ACCUMULATION. LITTLE CHANGE EXPECTED SYNOPTICALLY SPEAKING HEADED INTO MON WITH THE NW FLOW ALOFT AND THE ARCTIC AIR MASS LOCKED IN OVER THE REGION. THE BETTER LAKE EFFECT SNOW WL CONT TO FAVOR NW/ERN 1/3 OF UPR MI WITH ONLY SCT ACTIVITY AFFECTING VILAS CNTY. TEMPS WL REMAIN THE BIG STORY AS MUCH OF N-CNTRL AND CNTRL WI WL NOT GET OUR OF THE NEGATIVE NUMBERS (GENERALLY ZERO TO 5 BELOW). ON TOP OF THE VERY COLD TEMPS WL BE A SUSTAINED W-NW WIND OF 10 TO 20 MPH WHICH WOULD PLACE WIND CHILL READINGS AT -20 DEGS OR COLDER FOR ALMOST THE ENTIRE FCST AREA...THUS HEADLINES BY NEED TO BE EXTENDED RIGHT THRU MON. THE AREA OF HI PRES IS FCST TO EXTEND FROM THE UPR MS VALLEY TO THE OZARKS MON NGT WITH WINDS BACKING A BIT MORE TO A 280 OR 290 DEGREE DIRECTION WHICH IS EVEN MORE OF AN UNFAVORABLE TRAJ TO BRING LAKE EFFECT INTO VILAS CNTY...THUS AM NOT EXPECTING MUCH (IF ANY ACCUMULATION). THERE WL BE SOME WIND THRU THE NGT WHICH WOULD HELP TO PREVENT TEMPS FROM COMPLETELY FREE-FALLING. EVEN SO...MON NGT APPEARS TO BE THE COLDEST NGT WITH READINGS DROPPING TO NEAR 20 BELOW ZERO N-CNTRL...AROUND 5 BELOW ZERO ALONG THE LK MI SHORELINE. ADD IN SOME WIND AND WE ARE LOOKING AT ADDITIONAL WIND CHILL HEADLINES FOR ALL OF NE WI. THE HI PRES FINALLY REACHES THE WRN GREAT LAKES REGION ON TUE WHICH SHOULD ALLOW FOR WINDS TO LIGHTEN UP (GENERALLY IN THE 5-10 MPH RANGE). THIS SFC HI DOES NOT HAVE A LOT OF DRY AIR WITH IT AS FCST SOUNDINGS INDICATE SEVERAL LAYERS OF MOISTURE...THUS PARTLY SUNNY SKIES WOULD BE THE BEST CASE SCENARIO. MAX TEMPS WL AGAIN STRUGGLE TO REACH ZERO...ESPECIALLY AFTER THE BITTERLY COLD START TO THE DAY. MAY NEED TO TAKE VALUES DOWN A DEGREE OR TWO FROM THE PREVIOUS FCST. CHANGES IN THE OVERALL SYNOPTIC PATTERN BEGINS TUE NGT AS THE WRN CONUS UPR RDG STARTS TO MOVE TOWARD THE ROCKIES AND WEAKEN A BIT. ONE MORE VERY COLD NGT ANTICIPATED ACROSS NE WI WITH THE SFC HI PRACTICALLY OVERHEAD (THUS LIGHT WINDS). LOOK FOR MIN TEMPS TO RANGE FROM 10 BELOW TO 15 BELOW NORTH TO AROUND ZERO LAKESIDE. SOME MODERATION IN TEMPS IS EXPECTED ON WED AS THE SFC HI SHIFTS TO OUR EAST ALLOWING WINDS TO BACK W-SW AND THE CORE OF THE UPR TROF PULLS FARTHER EAST. IN ADDITION...THE UPR RDG QUICKLY BREAKS DOWN OVER THE ROCKIES ALLOWING FOR SOME MILDER PACIFIC AIR TO BEGIN MOVING INTO THE CNTRL CONUS. SINCE THE MEAN FLOW TO BECOME LESS AMPLIFIED WITH THE BREAK DOWN OF THE UPR RDG...THIS WL ALLOW FOR A PACIFIC SYSTEM TO RACE EWD ACROSS THE CONUS WED NGT INTO FRI. AS ONE WOULD EXPECT...THE MDLS ARE HAVING SERIOUS TIMING ISSUES WITH THIS SYSTEM...AS WELL AS THE TRACK OF THE ACCOMPANYING SFC LOW. SIMPLY TAKING A ROUGH AVERAGE OF THE MDLS WOULD FAVOR THIS SYSTEM AFFECTING NE WI DURING THE THU- THU NGT TIME FRAME WITH SOME MEASURABLE SNOW. AMOUNTS COULD BE LIMITED DUE TO THE SPEED OF THE SYSTEM OVERALL...BUT WAY TOO EARLY TO DETERMINE SNOW EXTENT JUST YET. TEMPS ARE PROGGED TO WARM INTO THE TEENS TO LWR 20S FOR BOTH THU AND FRI...BUT THERE ARE SIGNS OF ANOTHER UPR RDG BUILDING ACROSS THE WRN CONUS TOWARD NEXT WEEKEND WHICH COULD DUMP ANOTHER COLD AIR MASS INTO THE GREAT LAKES. THIS AIR MASS WHILE COLD...WL NOT BE ANYTHING COMPARED TO THE IMPENDING ARCTIC BLAST FROM EARLIER IN THE WEEK. && .AVIATION...WHILE LIGHT MIXED PRECIPITATION HAS EXITED NORTHEAST WISCONSIN...THE BIGGEST AVIATION HAZARDS WILL ACCOMPANY AN ARCTIC COLD FRONTAL PASSAGE LATE THIS AFTERNOON AND THIS EVENING. SCT SNOW SHOWERS ARE STILL EXPECTED TO DEVELOP ALONG THE FRONT...WITH LOCAL VSBYS BLO 1SM. IN ADDITION...STRONG WEST WINDS WILL DEVELOP BEHIND THE FRONT AS ARCTIC AIR POURS ACROSS THE STATE...WITH GUSTS TO 35 TO 40 KTS...HIGHEST ACROSS C/EC WI AND ALONG THE LAKESHORE. LAKE EFFECT SNOW SHOWERS WILL DEVELOP IN NC WI TONIGHT...AND NW WINDS WILL BE STRONG ENOUGH TO CARRY SOME SNOW INTO RHI. IMPROVING CONDITIONS WILL OCCUR AFTER MIDNIGHT IN TERMS OF DIMINISHING WINDS...SNOW SHOWERS...AND INCREASING CIGS. VFR CONDITIONS TOMORROW UNDER ARCTIC HIGH PRESSURE. MPC && .GRB WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST SUNDAY FOR WIZ038>040-048>050. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR WIZ030-031-035>037-045. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR WIZ005-010-011-018-019-030-035-036. WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR WIZ022. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1039 AM CST SAT JAN 19 2013 .UPDATE...THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN AREA OF MIXED PRECIPITATION OVER NE WISCONSIN LATE THIS MORNING. THIS PRECIPITATION SHOULD EXIT BY AROUND MIDDAY...BUT COULD STILL LEAD TO SLICK ROADWAYS OVER DOOR COUNTY WHERE TEMPERATURES ARE CURRENTLY IN THE UPPER 20S. LOOKING AHEAD...A STRONG SHORTWAVE AND ARCTIC COLD FRONT ARE NOW MOVING QUICKLY EAST OVER NORTHERN MINNESOTA. BOTH THE 12Z NAM AND RUC SHOW THESE FEATURES REACHING NORTH-CENTRAL AND CENTRAL WISCONSIN AROUND 20-21Z AND NORTHEAST WISCONSIN BY AROUND 00Z. UPSTREAM OBS OVER NORTH DAKOTA AND NORTHERN MINNESOTA SHOW OBS IN THE 1-3SM RANGE...AND SUPPORT GOING WITH LIKELY SNOW SHOWERS OVER N-C WISCONSIN LATE THIS AFTERNOON. ALSO HAVE OBSERVED SEVERAL WIND GUSTS IN THE UPPER 30S TO LOWER 40S KTS BEHIND THE FRONT...WHERE A STRONG ISALLOBARIC COMPONENT IS LEADING TO HIGHER GUSTS. SINCE THE COLDER AIR BEHIND THE FRONT IS NOT PROGGED TO ARRIVE OVER THE FOX VALLEY AND LAKESHORE UNTIL 00Z...HAVE DELAYED THE WIND ADVISORY HEADLINES BY A FEW HOURS THERE. THE BEST PERIOD OF WIND IS DUE TO ARRIVE LATE THIS AFTERNOON THROUGH LATE THIS EVENING WHEN THE STRONGEST DESCENDING MOTION AND ISALLOBARIC PUSH ARRIVE. THINK THE ADVISORY ENDING TIME IS A BIT TOO LONG...BUT WILL RE-EXAMINE THAT LATER. MPC && .PREV DISCUSSION...ISSUED AT 625 AM CST SAT JAN 19 2013. SHORT TERM...TODAY THROUGH SUNDAY...PCPN TRENDS...STRONG WINDS... FALLING TEMPERATURES AND ASSOCIATED WIND ADVISORY/WIND CHILL/MARINE HEADLINES ARE THE MAIN FCST CONCERNS. CLIPPER LOW OVER NE ND/NW MN WILL TRACK THROUGH THE UPPER PENINSULA OF MICHIGAN TODAY...AND DRAG AN ARCTIC COLD FRONT THROUGH THE FCST AREA THIS AFTERNOON. SCT SNOW SHOWERS SEEN OVER THER MN ARROWHEAD AND FAR NW WI SHOULD BRUSH THROUGH NORTHERN WI THIS MORNING...AND ADDITIONAL SNOW SHOWERS WILL ACCOMPANY THE COLD FRONT THIS AFTERNOON. ALTHOUGH MOISTURE IS LACKING WITH THIS SYSTEM...VERY STG DYNAMICS ASSOC WITH A STG S/W TROF...THE LFQ OF AN UPPER LEVEL JET...DEEP MID-LEVEL FRONTOGENTIC FORCING AND STEEP 850-700 MB LAPSE RATES WILL HELP GENERATE SCT MODERATE SNOW SHOWERS ALONG THE FRONT THIS AFTERNOON. THIS COULD END UP BEING A HISA (HIGH IMPACT SUB-ADVISORY) EVENT...AS LOCALLY POOR VISIBILITIES WILL LIKELY OCCUR...AND WET ROADS WILL QUICKLY FREEZE AS TEMPERATURES PLUMMET BEHIND THE FRONT LATE THIS AFTERNOON. WILL MENTION THIS POSSIBILITY IN THE HWO...AND ADD AN EXTRA PARAGRAPH ABOUT IT IN THE WIND ADVISORY STATEMENT. THE DAY SHIFT CAN ISSUE AN SPS IF THE SNOW SHOWERS AND TRAVEL CONCERNS DEVELOP AS EXPECTED. HAVE MAINTAINED LIKELY POPS ACROSS NC WI FOR THIS AFTERNOON...WHERE MOST PLACES SHOULD PICK UP AN INCH OR SO OF SNOW THIS AFTERNOON. LOCALLY HIGHER AMOUNTS ARE POSSIBLE IN VILAS COUNTY. PCPN TRENDS WILL TRANSITION TO MORE OF A TYPICAL NW FLOW LAKE EFFECT PATTERN TONIGHT INTO SUNDAY. THE SETUP IS NEVER PERFECT FOR BIG ACCUMS...AS THE WIND TRAJECTORY IS BIT TOO WESTERLY AT TIMES...STG SUBSIDENCE OCCURS AT TIMES...AND LLVL TEMPS BECOME TOO COLD FOR DENDRITES BY MID-EVENING TONIGHT. PLAN TO MENTION ADDITIONAL ACCUMS OF 1 TO 3 INCHES IN VILAS COUNTY TONIGHT AND ANOTHER INCH ON SUNDAY. STG CAA AND SUBSIDENCE IN THE WAKE OF THE FRONT...COMBINED WITH 925 MB WINDS 40-45 KTS/850 MB WINDS OF 45-55 KT...AND STEEP LLVL LAPSE RATES...SHOULD RESULT IN WIND GUSTS TO 45 TO 50 MPH ACROSS MOST OF C/EC WI AND THE LAKESHORE LATE THIS AFTERNOON AND TONIGHT. HAVE ISSUED A WIND ADVISORY FOR THIS AREA. THE WINDS WILL SUBSIDE A BIT OVERNIGHT...BUT THE COMBINATION OF WIND/TEMPS WILL PRODUCE WIND CHILLS AS COLD AS -25 OVER MUCH OF NC/C WI OVERNIGHT INTO SUNDAY MORNING. HAVE ISSUED A WIND CHILL ADVISORY FOR THAT AREA. LONG TERM...SUNDAY NGT THRU NEXT FRI. THE MAIN STORY FOR THE FIRST PART OF THE EXTENDED FCST TO BE THE ARCTIC BLAST WHICH WL SETTLE OVER THE REGION WITH THE COLDEST AIR THIS WINTER SEASON. NOT UNTIL THE WRN CONUS UPR RDG BREAKS DOWN AT MID-WEEK WL THE ARCTIC AIR BEGIN TO LEAVE WI...TO QUICKLY BE FOLLOWED BY A RELATIVELY STRONG/FAST-MOVING SHORTWAVE TROF ACROSS THE NRN TIER OF STATES. THIS SYSTEM WOULD IMPACT NE WI THU-THU NGT AND BRING THE NEXT CHC FOR MEASURABLE SNOW. TEMPS BY LATE IN THE WORK WEEK SHOULD AT LEAST APPROACH NORMAL ALTHO ANOTHER COOL DOWN IS HINTED AT BY THE MDLS FOR NEXT WEEKEND. ARCTIC AIR WL CONT TO POUR INTO THE GREAT LAKES SUNDAY NGT WITH 8H TEMPS OVER NW WI APPROACHING -30C. THE PRESSURE GRADIENT IS STILL FAIRLY TIGHT BETWEEN THE DEPARTED CLIPPER OVER SE CANADA AND STRONG HI PRES OVER THE NRN/CNTRL PLAINS. EXPECT TO SEE WIND CHILL HEADLINES TO BE ISSUED WITH MIN TEMPS RANGING FROM THE MID-TEENS BELOW ZERO N-CNTRL TO AROUND ZERO LAKESIDE...COUPLED WITH W-NW WINDS AROUND 10 MPH...TO SEND WIND CHILLS INTO THE -20 TO -32 DEGREE RANGE. THESE W-NW WINDS ARE NOT A FAVORABLE TRAJ FOR HEAVY LAKE EFFECT SNOW SHWRS OVER VILAS CNTY...HOWEVER ANTICIPATE SEEING AT LEAST SCT SNOW SHWR ACTIVITY REACH THE FAVORED SNOWBELT AREAS OF THE CNTY WITH PERHAPS UP TO AN INCH OF ACCUMULATION. LITTLE CHANGE EXPECTED SYNOPTICALLY SPEAKING HEADED INTO MON WITH THE NW FLOW ALOFT AND THE ARCTIC AIR MASS LOCKED IN OVER THE REGION. THE BETTER LAKE EFFECT SNOW WL CONT TO FAVOR NW/ERN 1/3 OF UPR MI WITH ONLY SCT ACTIVITY AFFECTING VILAS CNTY. TEMPS WL REMAIN THE BIG STORY AS MUCH OF N-CNTRL AND CNTRL WI WL NOT GET OUR OF THE NEGATIVE NUMBERS (GENERALLY ZERO TO 5 BELOW). ON TOP OF THE VERY COLD TEMPS WL BE A SUSTAINED W-NW WIND OF 10 TO 20 MPH WHICH WOULD PLACE WIND CHILL READINGS AT -20 DEGS OR COLDER FOR ALMOST THE ENTIRE FCST AREA...THUS HEADLINES BY NEED TO BE EXTENDED RIGHT THRU MON. THE AREA OF HI PRES IS FCST TO EXTEND FROM THE UPR MS VALLEY TO THE OZARKS MON NGT WITH WINDS BACKING A BIT MORE TO A 280 OR 290 DEGREE DIRECTION WHICH IS EVEN MORE OF AN UNFAVORABLE TRAJ TO BRING LAKE EFFECT INTO VILAS CNTY...THUS AM NOT EXPECTING MUCH (IF ANY ACCUMULATION). THERE WL BE SOME WIND THRU THE NGT WHICH WOULD HELP TO PREVENT TEMPS FROM COMPLETELY FREE-FALLING. EVEN SO...MON NGT APPEARS TO BE THE COLDEST NGT WITH READINGS DROPPING TO NEAR 20 BELOW ZERO N-CNTRL...AROUND 5 BELOW ZERO ALONG THE LK MI SHORELINE. ADD IN SOME WIND AND WE ARE LOOKING AT ADDITIONAL WIND CHILL HEADLINES FOR ALL OF NE WI. THE HI PRES FINALLY REACHES THE WRN GREAT LAKES REGION ON TUE WHICH SHOULD ALLOW FOR WINDS TO LIGHTEN UP (GENERALLY IN THE 5-10 MPH RANGE). THIS SFC HI DOES NOT HAVE A LOT OF DRY AIR WITH IT AS FCST SOUNDINGS INDICATE SEVERAL LAYERS OF MOISTURE...THUS PARTLY SUNNY SKIES WOULD BE THE BEST CASE SCENARIO. MAX TEMPS WL AGAIN STRUGGLE TO REACH ZERO...ESPECIALLY AFTER THE BITTERLY COLD START TO THE DAY. MAY NEED TO TAKE VALUES DOWN A DEGREE OR TWO FROM THE PREVIOUS FCST. CHANGES IN THE OVERALL SYNOPTIC PATTERN BEGINS TUE NGT AS THE WRN CONUS UPR RDG STARTS TO MOVE TOWARD THE ROCKIES AND WEAKEN A BIT. ONE MORE VERY COLD NGT ANTICIPATED ACROSS NE WI WITH THE SFC HI PRACTICALLY OVERHEAD (THUS LIGHT WINDS). LOOK FOR MIN TEMPS TO RANGE FROM 10 BELOW TO 15 BELOW NORTH TO AROUND ZERO LAKESIDE. SOME MODERATION IN TEMPS IS EXPECTED ON WED AS THE SFC HI SHIFTS TO OUR EAST ALLOWING WINDS TO BACK W-SW AND THE CORE OF THE UPR TROF PULLS FARTHER EAST. IN ADDITION...THE UPR RDG QUICKLY BREAKS DOWN OVER THE ROCKIES ALLOWING FOR SOME MILDER PACIFIC AIR TO BEGIN MOVING INTO THE CNTRL CONUS. SINCE THE MEAN FLOW TO BECOME LESS AMPLIFIED WITH THE BREAK DOWN OF THE UPR RDG...THIS WL ALLOW FOR A PACIFIC SYSTEM TO RACE EWD ACROSS THE CONUS WED NGT INTO FRI. AS ONE WOULD EXPECT...THE MDLS ARE HAVING SERIOUS TIMING ISSUES WITH THIS SYSTEM...AS WELL AS THE TRACK OF THE ACCOMPANYING SFC LOW. SIMPLY TAKING A ROUGH AVERAGE OF THE MDLS WOULD FAVOR THIS SYSTEM AFFECTING NE WI DURING THE THU- THU NGT TIME FRAME WITH SOME MEASURABLE SNOW. AMOUNTS COULD BE LIMITED DUE TO THE SPEED OF THE SYSTEM OVERALL...BUT WAY TOO EARLY TO DETERMINE SNOW EXTENT JUST YET. TEMPS ARE PROGGED TO WARM INTO THE TEENS TO LWR 20S FOR BOTH THU AND FRI...BUT THERE ARE SIGNS OF ANOTHER UPR RDG BUILDING ACROSS THE WRN CONUS TOWARD NEXT WEEKEND WHICH COULD DUMP ANOTHER COLD AIR MASS INTO THE GREAT LAKES. THIS AIR MASS WHILE COLD...WL NOT BE ANYTHING COMPARED TO THE IMPENDING ARCTIC BLAST FROM EARLIER IN THE WEEK. && .AVIATION...LOW CLOUDS REMAINED ACROSS FAR NORTHERN WI EARLY THIS MORNING...AND SCT SNOW SHOWERS WILL LIKELY IMPACT THAT AREA THIS MORNING. HOWEVER...THE BIGGEST AVIATION HAZARDS WILL ACCOMPANY AN ARCTIC COLD FRONTAL PASSAGE THIS AFTERNOON. SCT SNOW SHOWERS WILL DEVELOP ALONG THE FRONT...WITH LOCAL VSBYS BLO 1SM. IN ADDITION... STRONG WEST WINDS WILL DEVELOP LATE THIS AFTERNOON AND TONIGHT... WITH GUSTS TO 35 TO 45 KTS...HIGHEST ACROSS C/EC WI AND ALONG THE LAKESHORE. LAKE EFFECT SNOW SHOWERS WILL DEVELOP IN NC WI LATER TODAY INTO TONIGHT...ESPECIALLY ACROSS VILAS COUNTY. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 6 PM THIS EVENING TO 3 AM CST SUNDAY FOR WIZ038>040-048>050. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR WIZ030-031-035>037-045. WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR WIZ005-010-011-018-019-030-035-036. WIND ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR WIZ022. && $$