Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/05/15


AREA FORECAST DISCUSSION
NWS PUEBLO CO
1223 PM MST SAT JAN 3 2015 .UPDATE... ISSUED AT 1221 PM MST SAT JAN 3 2015 LATEST HRRR IS SHOWING SIGNIFICANT SNOW ACCUMS ALONG AND W OF I-25 THIS AFTERNOON AND EVE...UP TO 7 INCHES IN SPOTS. MAY BE A BIT OVERDONE...BUT IS IN AGREEMENT WITH OVERALL MODEL CONSENSUS ON THE BEST SNOW POTENTIAL...AND UPSTREAM OBS SUPPORT WIDESPREAD LIGHT TO MDT SNOW. SO HAVE HOISTED A SNOW ADVISORY FOR THAT AREA THROUGH THIS EVE. ROSE UPDATE ISSUED AT 907 AM MST SAT JAN 3 2015 HAVE MADE SOME SIGNIFICANT REVISIONS TO THE FORECAST...MAINLY TO DELAY TIMING OF PRECIP A BIT THIS AFTERNOON AS MOST OF THE GUIDANCE SHOWS TIMING OF THE WIDESPREAD PRECIP TO BE CLOSE TO OR AFTER 00Z. SATELLITE AND ALSO SHOW A FAIR AMOUNT OF SUN OVER MUCH OF OUR CWA CURRENTLY. ONLY AREAS REALLY SEEING CLOUDS AND PRECIP ATTM ARE BACA COUNTY AND THE UPPER ARKANSAS/LAKE COUNTY. HAVE CUT BACK POPS FOR THE OTHER AREAS. MAIN DILEMMA TODAY WILL BE THE SNOW AM`S OVER THE ERN PLAINS AND MTS. BULK OF THE 12-15Z GUIDANCE IS CURRENTLY SHOWING THE BEST POTENTIAL FOR SNOW ACCUMS TO BE OVER THE SRN MTS AND SRN I-25 CORRIDOR FROM KPUB TO KRTN. SOME OF THE HIGH RES GUIDANCE...INCLUDING THE HRRR...SHOWS SOME BANDS OF SNOW IN THIS AREA WITH POTENTIAL FOR SNOW AMTS GREATER THAN FOUR INCHES...POSSIBLY REACHING ADVISORY CRITERIA. HOWEVER...OTHER MODELS INCLUDING THE NAM SHOW LOWER QPF. WILL HAVE TO TAKE A WAIT AND SEE APPROACH FOR THIS AREA. THE SNOW ADVISORY FOR NRN EL PASO IS ALSO ON SHAKY GROUND...BUT WITH SOME GUIDANCE SHOWING PERSISTENT ACCUMS IN THE 1-3 INCH RANGE AND THE POTENTIAL FOR SOME BLOWING SNOW AND TRAVEL IMPACTS...WILL STAY THE COURSE FOR NOW. ROSE && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 357 AM MST SAT JAN 3 2015 CURRENTLY...AN UPPER LEVEL LOW IS MOVING ACROSS SOUTHERN NEW MEXICO AND SPREADING WIDESPREAD HIGH AND MID LEVEL CLOUDINESS ACROSS EASTERN COLORADO. THIS HAS HELPED KEEP TEMPERATURES UP SO FAR THIS MORNING WITH MOSTLY TEENS ACROSS THE REGION. RADAR INDICATES LIGHT RETURNS FROM EASTERN LAS ANIMAS...INTO BACA AND PROWERS COUNTIES BUT HAVE YET TO SEE ANY SNOW REPORTS FROM AREA OBSERVATIONS AT THIS TIME. THAT BEING SAID...ITS LIKELY THAT AT LEAST A LITTLE BIT OF LIGHT SNOW IS MAKING IT TO THE GROUND OVER THIS AREA AND WILL CONTINUE TO BE POSSIBLE THROUGH SUNRISE. TODAY...TWO UPPER LEVEL SYSTEMS TO DEAL WITH THROUGH THIS EVENING. FIRST IS THE UPPER LEVEL LOW OVER SOUTHERN NEW MEXICO...WHICH IS FORECAST TO EJECT NORTHEAST INTO CENTRAL OKLAHOMA BY THIS AFTERNOON. MODELS AND THE LATEST RADAR IMAGERY KEEP THE POTENTIAL FOR LIGHT SNOW GOING SOUTH OF A LAMAR TO TRINIDAD LINE THROUGH AROUND NOON. ANY ACCUMULATIONS APPEAR TO BE MINOR WITH UP TO AN INCH OR SO POSSIBLE OVER EXTREME SOUTHEASTERN BACA COUNTY. THE SECOND SYSTEM IS A SHORTWAVE TROUGH DROPPING SOUTH OUT OF THE NORTHERN ROCKIES. MODELS IN GOOD AGREEMENT WITH IT MOVING INTO EASTERN COLORADO BY THIS AFTERNOON. FOLLOWED A BLEND OF THE VARIOUS HIGH-RES MODELS AND THE NAM IN REGARDS TO FRONTAL AND PRECIPITATION TIMING. MODELS HAVE THE THE COLD FRONT DROPPING SOUTH OVER THE PALMER DIVIDE BY LATE MORNING...AND QUICKLY CLEARING THE EASTERN PLAINS BY MID AFTERNOON. AHEAD OF THE FRONT...TEMPERATURES WILL LIKELY WARM QUICKLY...WITH MID TO UPPER 30S AROUND THE PUEBLO REGION. AREAS UNDER CLOUD COVER TO THE EAST WILL LIKELY ONLY REACH THE 20S. COLD AIR WILL ADVECT QUICKLY BEHIND THE FRONT WITH 20S ACROSS THE REGION BY LATE AFTERNOON. AS FAR AS PRECIPITATION...EXPECT SNOW TO DEVELOP OVER THE CENTRAL MOUNTAINS THIS MORNING AS THE UPPER SYSTEM APPROACHES. SNOW IS FORECAST TO DEVELOP OVER THE PALMER DIVIDE ALONG THE FRONT...AND SPREAD SOUTH ACROSS THE PLAINS THROUGH THE AFTERNOON AND EARLY EVENING HOURS. THE PRIMARY FOCUS WILL BE THE PALMER DIVIDE...EASTERN MOUNTAINS AND SOUTHERN I-25 CORRIDOR. A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR NORTHERN EL PASO COUNTY...WITH STRONG WINDS BEHIND THE FRONT AND SNOW CAUSING HAZARDOUS TRAVEL CONDITIONS OVER MONUMENT HILL. AS FAR AS SNOW TOTALS...NORTHERN EL PASO COUNTY WILL SEE AROUND 1 TO 3 INCHES WHILE REST OF THE EASTERN PLAINS SEES LESS THAN 2 INCHES. THE CENTRAL AND EASTERN MOUNTAINS WILL LIKELY SEE 2 TO 4 INCHES WITH LOCALLY HIGHER AMOUNTS. TONIGHT...THE SHORTWAVE TROUGH IS FORECAST TO QUICKLY MOVE INTO THE CENTRAL PLAINS BY MIDNIGHT. MODELS IN GOOD AGREEMENT WITH SNOW WINDING DOWN FROM NORTH TO SOUTH BY MIDNIGHT...WITH A FEW LINGERING SNOW SHOWERS OVER THE CENTRAL AND EASTERN MOUNTAINS PERSISTING UNTIL SUNDAY MORNING. COLD AIR WILL CONTINUE TO ADVECT SOUTHWARD WITH OVERNIGHT LOWS BOTTOMING OUT IN THE SINGLE DIGITS...WITH A FEW LOCATIONS DROPPING BELOW ZERO BY SUNDAY MORNING. THE OTHER MAIN ISSUE FOR TONIGHT MAY BE WIND CHILL READINGS. WINDS WILL BE FAST TO SUBSIDE ALONG THE I-25 CORRIDOR...SO NOT ANTICIPATING WIND CHILL ISSUES THERE. BUT...OUT NEAR THE KANSAS BORDER...BREEZY CONDITIONS WILL LIKELY PREVAIL THROUGH THE OVERNIGHT HOURS. WIND CHILL READINGS WILL BE HOVERING AROUND ADVISORY THRESHOLDS...ESPECIALLY OVER KIOWA AND PROWERS COUNTIES. IF YOU HAVE TO BE OUTSIDE FOR ANY PROLONGED PERIODS LATE TONIGHT INTO SUNDAY MORNING...PREPARE FOR THE VERY COLD CONDITIONS. MOZLEY .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 357 AM MST SAT JAN 3 2015 ...MAIN FORECAST CHALLENGE NEXT WEEK WILL BE TEMPERATURES... IN GENERAL...SOUTHERN COLORADO WILL BE UNDER A DRY NORTHWEST FLOW PATTERN NEXT WEEK. THIS COULD YIELD SOME SNOW SHOWERS OVER THE CENTRAL MOUNTAINS AT TIMES...BUT...FOR THE MOST PART...SHOULD BE A DRY PATTERN. HOWEVER...BEING IN NORTHWEST FLOW...WITH ARCTIC AIR NOT TOO FAR AWAY ACROSS THE CENTRAL PLAINS...TEMPERATURE FORECASTS WILL BE A CHALLENGE. THERE WILL BE A FEW OPPORTUNITIES FOR ARCTIC AIR TO MAKE A QUICK RUN EAST INTO THE AREA THROUGH THE WEEK. SUNDAY WILL BE A TEMPERATURE RECOVERY DAY...WITH TEMPERATURES GENERALLY RUNNING BELOW BELOW AVERAGE...IN THE WAKE OF THE SYSTEM THAT MOVES THROUGH TODAY. MONDAY PRESENTS A TEMPERATURE CHALLENGE. CURRENT FORECAST IS FOR NEAR AVERAGE TEMPERATURES...BUT THIS MAY BE TOO CONSERVATIVE. FOR INSTANCE...AT PUEBLO...SOME GUIDANCE IS SUGGESTING 54 FOR A HIGH OR POSSIBLY EVEN 61...WHILE THE CURRENT FORECAST IS CALLING FOR JUST 46 DEGREES. CURRENT FORECAST IS THE END RESULT OF MODEL AND FORECASTER CONSENSUS. THIS TIME OF YEAR...WITH STRONG OVERNIGHT SURFACE INVERSIONS THAT LAST WELL INTO THE MORNING...COUPLED WITH LONG NIGHTS AND SHORT DAYS TO BEGIN WITH...IT WOULD BE TOUGH TO GET UP TO 60 DEGREES. SO FORECAST IS CONSERVATIVE. DOESN`T MEAN IT WON`T HAPPEN. CONCEPTUALLY...THE MODELS SHOW A MODERATE STRENGTH LEE TROUGH ON THE PLAINS WHICH COULD DRAW SOME CHINOOK WINDS OFF OF THE MOUNTAINS. IF THIS HAPPENS...WE COULD SEE A QUICK AND AGGRESSIVE WARMUP. SO...TEMPERATURE FORECASTS FOR MONDAY MAY HAVE TO GO WAY UP JUST DEPENDING ON HOW THINGS UNFOLD. TUESDAY...A SMALL AMOUNT OF COOL AIR FROM THE CENTRAL US PLAINS LOOKS TO MOVE INTO THE EASTERN HALF OF THE FORECAST AREA. THE SURGE DOESN`T LOOK EXCESSIVELY COOL AT THIS POINT...SO A FORECAST OF NEAR AVERAGE TEMPERATURES LOOKS REASONABLE AND THIS IS WHAT IS IN THE FORECAST AT THIS TIME. FOR THE SECOND OR THIRD DAY IN A ROW...MOST MODELS HAVE A MUCH STRONGER SURGE OF COLD AIR MOVING INTO THE EAST TUESDAY NIGHT AND WEDNESDAY. CURRENT FORECASTS ARE STARTING TO REFLECT INCREASING CONFIDENCE IN THE COOLING...AS REFLECTED BY HIGH TEMPERATURE FORECASTS ONLY IN THE MID 20S TO MID 30S OVER MOST OF THE PLAINS WEDNESDAY AFTERNOON. HOWEVER...HIGHS OVER THE EAST MAY HAVE TO BE PUSHED DOWN EVEN FURTHER. ALSO...THIS SURGE COULD BE STRONG ENOUGH TO PRODUCE SOME SCATTERED LIGHT PRECIPITATION OVER THE EASTERN PLAINS TUESDAY NIGHT INTO WEDNESDAY MORNING. THURSDAY COULD BE ANOTHER DAY WITH A QUICK WARMUP. MODELS ARE ONCE AGAIN SHOWING POSSIBLE LEE TROUGHING ON THE PLAINS WHICH WOULD DRAW WARMING CHINOOK WINDS OFF OF THE MOUNTAINS. CURRENT FORECAST HIGH TEMPERATURES IN THE MID 40S TO MID 50S ACROSS THE PLAINS MAY HAVE TO BE PUSHED UP 10 DEGREES IF SOME OF THE GUIDANCE IS RIGHT. THURSDAY NIGHT AND FRIDAY...MODELS ARE HINTING AT YET ANOTHER PUSH OF COOL AIR INTO THE EASTERN PLAINS. MUCH LIKE THE TUESDAY NIGHT/WEDNESDAY SYSTEM...THIS COULD RESULT IN HIGH TEMPERATURES COOLER THAN CURRENTLY FORECAST AND SOME SCATTERED LIGHT PRECIPITATION. AS ALWAYS...PLEASE STAY TUNED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1003 AM MST SAT JAN 3 2015 MAIN AVN CONCERN WILL BE THE COLD FRONT AND ASSOCIATED PRECIP MOVING THROUGH THE ERN CO PLAINS THIS AFTERNOON AND EVENING. LATEST FORECAST HAS SNOW BEGINNING OVER THE PALMER DVD IN ANOTHER HOUR OR SO...THEN ADVANCING SWD TO VC KCOS BY 20-21Z. A PERIOD OF -SN IS LIKELY AT KCOS...BUT SIGNIFICANT ACCUMS ARE NOT EXPECTED...POSSIBLY AN INCH OR LESS. SNOW POTENTIAL AT KPUB IS A LITTLE BETTER BY 22Z...AS SNOW BANDS DEVELOP SOUTH OF THE ARKANSAS. KPUB WILL BE ON THE NRN FRINGES OF THE ACCUMULATING SNOW AND COULD POTENTIALLY BE AFFECTED. MVFR CONDITIONS AT KPUB AND KCOS ARE EXPECTED...WITH OCCASIONAL IFR POSSIBLE. SNOW SHOULD WIND DOWN FROM N TO S BY 02-04Z...AND CONDITIONS SHOULD IMPROVE THEREAFTER AT KCOS AND KPUB. AT KALS...SNOW IS LESS LIKELY...BUT FG IS AGAIN EXPECTED TO DEVELOP AFTER 03Z TONIGHT...AND COULD PERSIST INTO THE MORNING TO 15-16Z ON MON. ROSE && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 10 PM MST THIS EVENING FOR COZ074- 075-079-080-084-087-088. && $$ UPDATE...ROSE SHORT TERM...MOZLEY LONG TERM...LW AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1028 AM MST SAT JAN 3 2015 .UPDATE... ISSUED AT 1028 AM MST SAT JAN 3 2015 CURRENT FORECAST LOOKS ON TRACK. COLD FRONT HAS MOVED THROUGH CHEYENNE IN THE PAST HOUR OR SO WITH NORTHERLY WINDS NOW GUSTING UP CLOSE TO 30 MPH. COLD FRONT SHOULD MOVE THROUGH THE DENVER AREA BY ABOUT NOON. SNOW WILL DEVELOP SHORTLY AFTER FRONTAL PASSAGE AND QUITE A BIT OF BLOWING SNOW IS EXPECTED ACROSS THE NORTHEAST PLAINS THROUGH THE AFTERNOON. THE UPPER DISTURBANCE SHOULD BE MOVING OUT OF THE STATE BY MID-EVENING WITH IMPROVING CONDITIONS ACROSS THE FORECAST AREA BY 10 PM...OR SOONER. WILL LET THE ADVISORY FOR SNOW AND BLOWING SNOW STAND AS IT IS. && .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 300 AM MST SAT JAN 3 2015 UPPER LEVEL DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE SOUTH AND SOUTHEAST THROUGH COLORADO THIS AFTERNOON AND EVENING WITH A RETURN TO WINTER CONDITIONS. MAIN CONCERNS WILL BE SNOWFALL POTENTIAL...BLOWING SNOW AND HAZARDOUS WINTER DRIVING CONDITIONS ON THE PLAINS. THE COLD FRONT HAS MOVED THROUGH PORTIONS OF NORTHEAST WYOMING AS OF 3 AM...AND IS EXPECTED TO BE OVER THE COLORADO BORDER AROUND 14-15Z AND THEN INTO THE DENVER AREA BETWEEN 11 AM AND NOON. EXPECT INCREASING AND GUSTY N-NE WINDS OF 20-35KT WHICH WILL CREATE SOME BLOWING SNOW. MOISTURE DEPTH INCREASES BEHIND FRONT WITH UPSLOPE FLOW. THERE IS WEAK TO MODERATE LARGE SCALE ASCENT WITH THIS SYSTEM...STRONGEST OVER THE NORTHEAST PLAINS. LATEST MODEL RUNS ARE A BIT LESS WITH SNOWFALL BUT STILL IN THE 1-3 INCH RANGE...HIGHEST OVER THE NE PLAINS EAST OF DENVER. DESPITE THE LOWER AMOUNTS...TRAVEL WILL BE TRICKY WITH CONSIDERABLE BLOWING AND DRIFTING SNOW. WILL LEAVE CURRENT ADVISORIES AS IS. THE LATEST RAP IS GENERATING HIGHER SNOWFALL AMOUNTS NEAR THE FOOTHILLS WITH ENHANCED UPSLOPE. THIS MAY BE A BIT OF A STRETCH BUT CERTAINLY BEARS WATCHING IN CASE ADVISORIES ARE NEEDED FURTHER WEST. THE STORM IS QUICK MOVING AS SNOW WILL RAPIDLY DIMINISH THIS EVENING WITH SNOW ENDING IN SOUTHERN SECTIONS AROUND MIDNIGHT. EXPECT CLEARING SKIES AS TEMPERATURES DROP BELOW ZERO AGAIN ON THE PLAINS. WITH BRISK WINDS CONTINUING TONIGHT ON THE PLAINS MAY NEED A WIND CHILL ADVISORY ON THE PLAINS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 217 AM MST SAT JAN 3 2015 STG NWLY FLOW ALOFT WILL BE OVER NRN CO FROM SUN INTO MON. CROSS- SECTIONS SHOW SOME MOISTURE EMBEDDED IN THE FLOW HOWEVER DESPITE FAVORABLE OROGRAPHICS INSTABILITY WILL BE POOR AS LAPSE RATES ONLY AVERAGE AROUND 3 C/KM THRU THE PERIOD. THUS EXPECT SOME PERIODS OF LIGHT SNOW. MEANWHILE WITH STG FLOW ALOFT THERE WILL BE SOME POTENTIAL FOR HIGH WINDS. OVERALL LOOKS LIKE THE HIGHEST WINDS WILL STAY MAINLY ABOVE TIMBERLINE ON SUNDAY DUE TO LACK OF MTN WAVE. LATE SUN NIGHT INTO MON THE MTN WAVE BECOMES MORE DEFINED WHICH MAY ALLOW FOR STG WINDS TO AFFECT AREAS IN AND NR THE FOOTHILLS. OVER NERN CO IT LOOKS DRY BOTH DAYS WITH MAIN PROBLEM BEING HIGH TEMPERATURES DUE TO LINGERING SNOWPACK. ON SUN WILL KEEP HIGHS IN THE UPPER TEENS TO LOWER 20S OVER THE FAR NERN CORNER WITH LOWER 30S POSSIBLE AROUND DENVER. IF INVERSIONS HOLD ALONG THE SOUTH PLATTE RIVER VALLEY THEN HIGHS MAY STRUGGLE TO GET OUT OF THE TEENS. ON MON SUBSTANTIAL WARMING IS FCST IN THE 850-700 MB LYR AS DOWNSLOPE FLOW OCCURS ALONG THE FRONT RANGE. AS A RESULT GUIDANCE TEMPS SHOOT UP INTO THE LOWER TO MID 50S AROUND DENVER WITH 40S ACROSS THE PLAINS. AT THIS POINT BELIEVE LINGERING SNOWPACK WILL STILL ALTER HIGHS SOMEWHAT SO WILL KEEP READINGS IN THE LOWER TO MID 40S AROUND DENVER WITH 30S ACROSS THE PLAINS. ON TUE THE FLOW ALOFT WILL BE WNW WITH NOT MUCH MOISTURE SHOWN IN THE CROSS-SECTIONS SO WILL ONLY MENTION A SLIGHT CHC OF SNOW IN THE MTNS WITH DRY CONDITIONS OVER NERN CO. AS FOR HIGHS BOTH THE GFS AND ECMWF SHOW A SURGE OF COOLER AIR AFFECTING NERN CO MON NIGHT INTO TUE MORNING. BY TUE AFTN THE GFS SHOWS THE SHALLOW LYR OF COOLER MIXING OUT ALONG THE FRONT RANGE WHILE THE ECMWF DOES NOT. AS A RESULT THERE IS A 10 DEGREE DIFFERENCE IN HIGH TEMPS OVER NERN CO. FOR NOW WILL KEEP READINGS IN THE LOWER TO MID 40S NEAR DENVER WITH LOWER TO MID 30S OVER THE FAR NERN PLAINS. FOR TUE NIGHT INTO WED APPEARS ANOTHER SHOT OF COLDER AIR WILL AFFECT NERN CO AS ARCTIC HIGH PRES BUILDS INTO THE NRN AND CNTRL PLAINS. ALTHOUGH NERN CO WILL NOT TAKE A DIRECT HIT COULD EASILY SEE HIGHS DROP BACK INTO THE TEENS OVER THE PLAINS WITH 20S ALONG THE FRONT RANGE. MEANWHILE CROSS-SECTIONS ARE SHOWING SOME POTENTIAL FOR FREEZING DRIZZLE OR VERY LIGHT SNOW LATE TUE NIGHT INTO WED MORNING OVER NERN CO. IN THE MTNS IT LOOKS DRY ON WED. ON THU DRY WNW FLOW ALOFT WILL BE OVER THE AREA AS A SFC LEE TROUGH DEVELOPS ALONG THE FRONT RANGE. THIS SHOULD ALLOW FOR WARMER TEMPS WITH READINGS RISING BACK INTO THE 40S ALONG THE FRONT RANGE. OVER THE NERN PLAINS HIGHS MAY STAY IN THE 35 TO 40 DEGREE RANGE. BY FRI THE GFS SHOWS A WEAK UPPER LEVEL RIDGE OVER THE AREA WHILE THE ECMWF HAS NWLY FLOW ALOFT. DESPITE THE DIFFERING UPPER LVL PATTERNS BOTH MODELS SHOW ANOTHER SHOT OF COOLER AIR MOVING INTO NERN CO THU NIGHT INTO EARLY FRI. THE ECMWF HAS NO PCPN OVER THE AREA WHILE THE GFS HAS SOME LIGHT PCPN OVER NERN CO. FOR NOW WILL KEEP FCST DRY AND HAVE HIGHS RANGING FM THE UPPER 20S OVER THE FAR NERN CORNER WITH 35 TO 40 AROUND DENVER. && .AVIATION...(FOR THE TAFS THROUGH 18Z SUNDAY MORNING) ISSUED AT 1028 AM MST SAT JAN 3 2015 NORTHERLY WINDS ARE SHOWING UP IN NORTHERN WELD COUNTY AND SHOULD SPREAD INTO DENVER AREA BETWEEN 18Z AND 19Z. CEILINGS HAVE ALREADY LOWERED TO 6000 FEET AGL AS THE AIRMASS ALOFT MOISTENS. AFTER FRONTAL PASSAGE...GUSTY NORTH-NORTHEAST WINDS WILL CONTINUE WITH IFR CONDITIONS DEVELOPING. HEAVIEST SNOW ACCUMULATIONS WILL PROBABLY BE BETWEEN 20Z AND 00Z. ACCUMULATIONS BETWEEN 2 AND 4 INCHES CAN BE EXPECTED. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 9 PM MST THIS EVENING FOR COZ041>051. && $$ UPDATE...DANKERS SHORT TERM...ENTREKIN LONG TERM...RPK AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
305 AM MST SAT JAN 3 2015 .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 300 AM MST SAT JAN 3 2015 UPPER LEVEL DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE SOUTH AND SOUTHEAST THROUGH COLORADO THIS AFTERNOON AND EVENING WITH A RETURN TO WINTER CONDITIONS. MAIN CONCERNS WILL BE SNOWFALL POTENTIAL...BLOWING SNOW AND HAZARDOUS WINTER DRIVING CONDITIONS ON THE PLAINS. THE COLD FRONT HAS MOVED THROUGH PORTIONS OF NORTHEAST WYOMING AS OF 3 AM...AND IS EXPECTED TO BE OVER THE COLORADO BORDER AROUND 14-15Z AND THEN INTO THE DENVER AREA BETWEEN 11 AM AND NOON. EXPECT INCREASING AND GUSTY N-NE WINDS OF 20-35KT WHICH WILL CREATE SOME BLOWING SNOW. MOISTURE DEPTH INCREASES BEHIND FRONT WITH UPSLOPE FLOW. THERE IS WEAK TO MODERATE LARGE SCALE ASCENT WITH THIS SYSTEM...STRONGEST OVER THE NORTHEAST PLAINS. LATEST MODEL RUNS ARE A BIT LESS WITH SNOWFALL BUT STILL IN THE 1-3 INCH RANGE...HIGHEST OVER THE NE PLAINS EAST OF DENVER. DESPITE THE LOWER AMOUNTS...TRAVEL WILL BE TRICKY WITH CONSIDERABLE BLOWING AND DRIFTING SNOW. WILL LEAVE CURRENT ADVISORIES AS IS. THE LATEST RAP IS GENERATING HIGHER SNOWFALL AMOUNTS NEAR THE FOOTHILLS WITH ENHANCED UPSLOPE. THIS MAY BE A BIT OF A STRETCH BUT CERTAINLY BEARS WATCHING IN CASE ADVISORIES ARE NEEDED FURTHER WEST. THE STORM IS QUICK MOVING AS SNOW WILL RAPIDLY DIMINISH THIS EVENING WITH SNOW ENDING IN SOUTHERN SECTIONS AROUND MIDNIGHT. EXPECT CLEARING SKIES AS TEMPERATURES DROP BELOW ZERO AGAIN ON THE PLAINS. WITH BRISK WINDS CONTINUING TONIGHT ON THE PLAINS MAY NEED A WIND CHILL ADVISORY ON THE PLAINS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 217 AM MST SAT JAN 3 2015 STG NWLY FLOW ALOFT WILL BE OVER NRN CO FROM SUN INTO MON. CROSS- SECTIONS SHOW SOME MOISTURE EMBEDDED IN THE FLOW HOWEVER DESPITE FAVORABLE OROGRAPHICS INSTABILITY WILL BE POOR AS LAPSE RATES ONLY AVERAGE AROUND 3 C/KM THRU THE PERIOD. THUS EXPECT SOME PERIODS OF LIGHT SNOW. MEANWHILE WITH STG FLOW ALOFT THERE WILL BE SOME POTENTIAL FOR HIGH WINDS. OVERALL LOOKS LIKE THE HIGHEST WINDS WILL STAY MAINLY ABOVE TIMBERLINE ON SUNDAY DUE TO LACK OF MTN WAVE. LATE SUN NIGHT INTO MON THE MTN WAVE BECOMES MORE DEFINED WHICH MAY ALLOW FOR STG WINDS TO AFFECT AREAS IN AND NR THE FOOTHILLS. OVER NERN CO IT LOOKS DRY BOTH DAYS WITH MAIN PROBLEM BEING HIGH TEMPERATURES DUE TO LINGERING SNOWPACK. ON SUN WILL KEEP HIGHS IN THE UPPER TEENS TO LOWER 20S OVER THE FAR NERN CORNER WITH LOWER 30S POSSIBLE AROUND DENVER. IF INVERSIONS HOLD ALONG THE SOUTH PLATTE RIVER VALLEY THEN HIGHS MAY STRUGGLE TO GET OUT OF THE TEENS. ON MON SUBSTANTIAL WARMING IS FCST IN THE 850-700 MB LYR AS DOWNSLOPE FLOW OCCURS ALONG THE FRONT RANGE. AS A RESULT GUIDANCE TEMPS SHOOT UP INTO THE LOWER TO MID 50S AROUND DENVER WITH 40S ACROSS THE PLAINS. AT THIS POINT BELIEVE LINGERING SNOWPACK WILL STILL ALTER HIGHS SOMEWHAT SO WILL KEEP READINGS IN THE LOWER TO MID 40S AROUND DENVER WITH 30S ACROSS THE PLAINS. ON TUE THE FLOW ALOFT WILL BE WNW WITH NOT MUCH MOISTURE SHOWN IN THE CROSS-SECTIONS SO WILL ONLY MENTION A SLIGHT CHC OF SNOW IN THE MTNS WITH DRY CONDITIONS OVER NERN CO. AS FOR HIGHS BOTH THE GFS AND ECMWF SHOW A SURGE OF COOLER AIR AFFECTING NERN CO MON NIGHT INTO TUE MORNING. BY TUE AFTN THE GFS SHOWS THE SHALLOW LYR OF COOLER MIXING OUT ALONG THE FRONT RANGE WHILE THE ECMWF DOES NOT. AS A RESULT THERE IS A 10 DEGREE DIFFERENCE IN HIGH TEMPS OVER NERN CO. FOR NOW WILL KEEP READINGS IN THE LOWER TO MID 40S NEAR DENVER WITH LOWER TO MID 30S OVER THE FAR NERN PLAINS. FOR TUE NIGHT INTO WED APPEARS ANOTHER SHOT OF COLDER AIR WILL AFFECT NERN CO AS ARCTIC HIGH PRES BUILDS INTO THE NRN AND CNTRL PLAINS. ALTHOUGH NERN CO WILL NOT TAKE A DIRECT HIT COULD EASILY SEE HIGHS DROP BACK INTO THE TEENS OVER THE PLAINS WITH 20S ALONG THE FRONT RANGE. MEANWHILE CROSS-SECTIONS ARE SHOWING SOME POTENTIAL FOR FREEZING DRIZZLE OR VERY LIGHT SNOW LATE TUE NIGHT INTO WED MORNING OVER NERN CO. IN THE MTNS IT LOOKS DRY ON WED. ON THU DRY WNW FLOW ALOFT WILL BE OVER THE AREA AS A SFC LEE TROUGH DEVELOPS ALONG THE FRONT RANGE. THIS SHOULD ALLOW FOR WARMER TEMPS WITH READINGS RISING BACK INTO THE 40S ALONG THE FRONT RANGE. OVER THE NERN PLAINS HIGHS MAY STAY IN THE 35 TO 40 DEGREE RANGE. BY FRI THE GFS SHOWS A WEAK UPPER LEVEL RIDGE OVER THE AREA WHILE THE ECMWF HAS NWLY FLOW ALOFT. DESPITE THE DIFFERING UPPER LVL PATTERNS BOTH MODELS SHOW ANOTHER SHOT OF COOLER AIR MOVING INTO NERN CO THU NIGHT INTO EARLY FRI. THE ECMWF HAS NO PCPN OVER THE AREA WHILE THE GFS HAS SOME LIGHT PCPN OVER NERN CO. FOR NOW WILL KEEP FCST DRY AND HAVE HIGHS RANGING FM THE UPPER 20S OVER THE FAR NERN CORNER WITH 35 TO 40 AROUND DENVER. && .AVIATION...(FOR THE TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 217 AM MST SAT JAN 3 2015 SURFACE COLD FRONT WILL MOVE ACROSS TERMINALS IN THE 17-18Z TIME FRAME AS WINDS INCREASE FROM THE NORTH AND NORTHEAST WITH GUSTS UP TO 30KT. SNOW WILL DEVELOP 1-2 HOURS BEHIND THE FRONT WITH MVFR/IFR CONDITIONS DEVELOPING THIS AFTERNOON. EXPECT SNOWFALL THE HEAVIEST BETWEEN 21Z-01Z WITH TOTAL SNOWFALL OF 1-3 INCHES. SNOW WILL DIMINISH THIS EVENING WITH SOME CLEARING OVERNIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 9 PM MST THIS EVENING FOR COZ041>051. && $$ SHORT TERM...ENTREKIN LONG TERM...RPK AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS ALBANY NY
941 PM EST SUN JAN 4 2015 .SYNOPSIS... ONE COLD FRONT HAS ALREADY CROSSED OUR REGION. ANOTHER COLD FRONT WILL CROSS THE REGION TOWARD DAYBREAK. THIS WILL BE THE ONE THAT REALLY BRINGS THE COLD AIR ALONG WITH MORE GUSTY WINDS AND ADDITIONAL SHOWERS OF MOSTLY SNOW...MAINLY NORTHWEST OF ALBANY.IT WILL BE BLUSTERY AND COLD MONDAY. A CLIPPER LOOKS TO BRING A LITTLE SNOW ON TUESDAY FOLLOWED BY EVEN COLDER WEATHER WEDNESDAY AND THURSDAY. && .NEAR TERM /THROUGH MONDAY/... AS OF 945 PM EST...A COLD FRONT HAS SLIPPED THROUGH MOST OF OUR REGION. HOWEVER...AS THE RIGHT REAR REGION OF A 150KT JET HAS WORKED INTO OUR REGION...IT HAS ALLOWED ANOTHER AREA OF SHOWERS TO EXPAND IN OUR SOUTHEAST ZONES. HAD TO INCREASE POPS IN THAT THAT AREA FOR AWHILE THIS EVENING. THIS RR REGION WILL SHIFT TO OUR SOUTH AFTER MIDNIGHT TAKING THOSE SHOWERS WITH IT. MEANWHILE...A SECONDARY COLD FRONT...THE ONE WITH ARCTIC AIR...WAS WORKING INTO WESTERN NEW YORK. THIS FRONT WILL CROSS OUR REGION TOWARD DAYBREAK BRINGING PERHAPS A STRAY SHOWER ON ITS OWN...ALONG WITH MORE GUSTY WINDS AND THE REAL TEMPERATURE CHANGE. FOR THIS UPDATE...TRENDED HOURLY TEMPERATURES UPWARD A BIT AS THEY WILL ONLY SLOWLY FALL THROUGH THE EARLY OVERNIGHT...NOT FALLING TO BELOW FREEZING UNTIL DAYBREAK...FROM THE HUDSON VALLEY EASTWARD. TEMPERATURES WERE CLOSE TO FREEZING ACROSS THE ADIRONDACKS...AND WILL DROP BELOW FREEZING ACROSS THE REMAINDER OF THE HIGHER TERRAIN SHORTLY AFTER MIDNIGHT. LAKE EFFECT SHOWERS WERE BEGINNING TO WORK INTO THE ADIRONDACKS...PROBABLY A SNOW RAIN MIX IN THE VALLEYS...ALL SNOW HIGHER TERRAIN...BUT WILL SWITCH TO ALL SNOW BY MIDNIGHT. WE WILL KEEP ALL ADVISORIES UP THE WAY THEY WERE HANDED TO US. BY DAYBREAK...LOWS WILL BE DOWN NEAR 20 ACROSS THE DACKS AND MUCH OF THE REMAINDER OF THE ELEVATED TERRAIN. VALLEY AREAS WILL BE CLOSER TO 30. && .SHORT TERM /MONDAY NIGHT/... LAKE EFFECT SNOW ADVISORY ISSUED FROM 7 PM SUNDAY TO 7 AM MONDAY FOR NORTHERN HERKIMER AND HAMILTON COUNTIES... ...LAKE EFFECT SNOW ADVISORY ISSUED FROM 4 AM MONDAY TO 7 PM MONDAY FOR SOUTHERN HERKIMER...FULTON AND MONTGOMERY COUNTIES. THE ADVISORIES ARE FOR SNOW AND BLOWING SNOW WITH GUSTY WINDS OF 35 TO 45 MPH. OUR CONFIDENCE WAS NOT GREAT ENOUGH TO ISSUE A WIND ADVISORY FOR PARTS OF THE REGION SUNDAY NIGHT...THOUGH A 3RD PERIOD ADVISORY MAY BE NEEDED FOR MONDAY...AS BETTER MOMENTUM TRANSFER IS EXPECTED...BUT FOR NOW WIDESPREAD 46-57 MPH WIND GUSTS ARE NOT ANTICIPATED FOR SUNDAY NIGHT INTO MONDAY. THIS WILL CONTINUE TO BE MONITORED. TONIGHT...COLD FRONT MOVES ACROSS THE REGION WITH STRONG LOW LEVEL COLD ADVECTION EXPECTED. WESTERLY UPSLOPE SNOW SHOWERS WILL INITIALLY IMPACT THE WRN DACKS AND SRN GREENS MTNS WITH MORE SCT RAIN AND SNOW SHOWER ACTIVITY AWAY FROM THESE AREAS. THE LATEST HIRES WRF AND 3-KM HRRR INDICATE A TRANSITION FROM THE WESTERLY UPSLOPE SNOW SHOWERS OVER THE WRN DACKS TO AN ORGANIZED SINGLE BAND. BUFKIT PROFILES JUST DOWNSTREAM OF LAKE ONTARIO INDICATED MODERATE INSTABILITY WITH AN INVERSION HEIGHT CLOSE TO 10 KFT. HOWEVER...THE BAND IS EXPECTED TO FORM AND QUICKLY TRANSITION S/SE WITH THE STRONG VEERING WIND PROFILE IN THE BOUNDARY LAYER. THE LOW LEVEL FLOW STARTS AT 260-270 DEGS AND THEN SHIFTS TO A 280 TO 290 DEG LOW-LEVEL TRAJECTORY. A QUICK BLAST OF HVY SNOW SHOWERS IS ANTICIPATED FOR THE WRN DACKS WITH 3 TO 6 INCHES OF SNOW WITH PERHAPS SOME 4 TO 8 INCH AMOUNTS JUST SOUTH OF OLD FORGE AND INLET. THE TRANSITORY BAND MOVES INTO SRN HERKIMER COUNTY...AND THE W-CNTRL MOHAWK VALLEY BTWN 4-7 AM. THE NAM AND HIRES WRF SHOW A MULTI-LAKE CONNECTION WITH MDT INSTABILITY CLASS AT KUCA BUFKIT PROFILE. THIS AREA MAY NEED AN UPGRADE LATER...BUT WE PUT THE ENTIRE W-CNTRL MOHAWK VALLEY CORRIDOR WAS ALSO PLACED IN A LAKE EFFECT SNOW ADVISORY FOR SNOW AND BLOWING SNOW. ADVISORY WIND LEVEL GUSTS WILL BE CLOSE WITH 35 TO 45 MPH GUSTS FORECASTED. LOWS WILL BE MUCH COLDER IN THE TEENS TO M20S WITH SOME SINGLE DIGITS OVER THE ADIRONDACK PARK...AND U20S OVER THE MID HUDSON VALLEY. MONDAY...THE BETTER PRESSURE RISES PASS NORTH OF ST LAWRENCE RIVER VALLEY AND NRN NY BTWN 12Z-18Z MON 8-10 HPA/6 HRS. THE ISALLOBARIC COUPLET IS IMPRESSIVE AS THE CYCLONE DEEPENS AND INTENSIFIES TO ABOUT 980 HPA OVER THE GULF OF ST LAWRENCE BY 12Z/MON. SOME SUSTAINED WESTERLY WINDS OF 15 TO 25 MPH WITH GUSTS 35 TO 45 MPH ARE EXPECTED. THE 10-M WINDS ON THE GFSMOS PRODUCT FOR KALB ARE IMPRESSIVE IN THE 18-24 KT SUSTAINED RANGE. THE BUFKIT MOMENTUM TRANSFER PROFILES SHOW 40 KTS WILL NEED TO MIXED FROM 2.5 KFT AGL FOR WIND ADVISORY CRITERIA TO BE MET. ANY WIND FLAGS WILL BE MONITORED BY LATER SHIFTS. IT DOES LOOK PLAUSIBLE THAT SOME LAKE EFFECT SHOWERS MAY SNEAK DOWN THE MOHAWK RIVER VALLEY INTO THE CAPITAL REGION AND NRN TACONICS. HIGH CHC AND LIKELY POPS WERE USED LATE MONDAY MORNING INTO THE PM FOR A COATING TO PERHAPS A HALF AN INCH OF SNOW. SOME OF THE UPSLOPE AREAS OF THE SRN GREENS IN THE SRN VT...TACONICS...AND NRN BERKS COULD GET AN INCH OR TWO OR SNOW. THE ADVISORY AREA HIGHLIGHTED WILL LIKELY RECEIVE 3 TO 6 INCHES WITH SOME ISOLATED 4 TO 8 INCH AMOUNTS. THE INVERSION HEIGHTS DO LOWER IN THE AFTERNOON...AND THE SHEAR INCREASES SO THE DOWNSTREAM TRAJECTORY WILL DECREASE. MAX TEMPS MAY BE IN THE MORNING...AND TEMPS MAY CONTINUE TO FALL SLOWLY IN THE AFTERNOON IN THE POTENT COLD ADVECTION REGIME...AS H850 TEMPS CRASH INTO THE -17C TO -22C RANGE ACROSS THE FCST AREA. DAYTIME HIGHS WILL BE IN THE M20S TO L30S FROM THE TRI CITIES SOUTH AND EAST...AND TEENS TO L20S NORTH AND WEST WITH SOME SINGLE NUMBERS OVER THE SRN DACKS. WIND CHILLS WILL RANGE FROM 10 BELOW TO 10 ABOVE ZERO. MONDAY NIGHT...LAKE EFFECT SNOW BAND LIFTS BACK NORTHWARD...AS THE FLOW BACKS WITH AN APPROACHING SHORT-WAVE/CLIPPER LOW FROM THE GREAT LAKES REGION AND MIDWEST. HIGH PRESSURE BRIEFLY BUILDS IN FROM QUEBEC WITH A VERY COLD NIGHT EXPECTED. THE WINDS SHOULD DIMINISH...AND FRIGID TEMPS ARE ANTICIPATED WITH LOWS BELOW ZERO OVER THE SRN DACKS...AND PARTS OF THE LAKE REGION REGION...AND ZERO TO 10 ABOVE IN MOST OTHER LOCATIONS WITH SOME LOWER TEENS IN THE CAPITAL DISTRICT AND MID HUDSON VALLEY. CLOUDS WILL INCREASE IN THE FRIGID AIR MASS WITH THE BETTER CHANCE FOR LIGHT SNOW AND SCT SNOW SHOWERS ON TUE. && .LONG TERM /TUESDAY THROUGH SUNDAY/... VERY COLD TEMPERATURES AND ACTIVE WEATHER THIS WEEK...WITH THE COLDEST TEMPERATURES OF THE WINTER EXPECTED WEDNESDAY NIGHT AND THURSDAY WITH LIFE-THREATENING WIND CHILLS POSSIBLE. A QUICK MOVING NORTHERN STREAM CLIPPER SYSTEM WILL BRING A PERIOD OF LIGHT SNOW TO THE AREA TUESDAY. THIS SYSTEM IS EXPECTED TO PASS OVER THE OHIO VALLEY AND MOVE OFF THE DELMARVA. IT WILL HAVE LIMITED MOISTURE BUT GOOD FORCING. LOOKING AT HIGH RATIO SNOWFALL. AT THIS TIME EXPECT BELOW ADVISORY LEVEL ACCUMULATIONS. HIGHS WILL BE AROUND 10 DEGREES BELOW NORMAL. THE NEXT QUICK MOVING LOW PRESSURE SYSTEM AND NORTHERN STREAM SHORT WAVE WILL BE IN ITS HEELS. WILL HAVE CONTINUING CHANCES FOR SNOW SHOWERS TUESDAY NIGHT WITH SOME LAKE EFFECT/ENHANCEMENT INTO THE WESTERN ADIRONDACKS. EXPECT SNOW SHOWERS AND POSSIBLY SNOW SQUALLS AS THE ARCTIC BOUNDARY APPROACHES AND MOVES THROUGH WEDNESDAY. THIS SYSTEM/FRONT WILL BE THE ONE THAT OPENS THE DOOR TO THE ARCTIC AIRMASS WITH ITS PASSAGE STRONG COLD AIR ADVECTION WILL BEGIN. 850 MB TEMPERATURES ARE MODELED TO DROP TO -25 TO -30 DEGREES CELSIUS ACROSS THE FORECAST AREA WEDNESDAY NIGHT. SURFACE TEMPERATURES ARE FORECAST TO PLUMMET RANGING FROM AROUND 1 DEGREES TO AROUND 20 DEGREES BELOW ZERO...AROUND 20 DEGREES BELOW NORMAL. IN ADDITION...THE PRESSURE GRADIENT ACROSS THE REGION WILL BE TIGHT BETWEEN THE DEPARTING LOW PRESSURE SYSTEM AND AN ADVANCING HIGH RESULTING IN BRISK AND GUSTY NORTHWEST WINDS. THE COMBINATION OF THE BITTER TEMPERATURES AND BRISK WINDS WILL RESULT IN DANGEROUS TO LIFE-THREATENING WIND CHILL VALUES WEDNESDAY NIGHT INTO THURSDAY MORNING. WILL KEEP MENTION IN THE HAZARDOUS WEATHER OUTLOOK. THURSDAY WILL BE A FRIGID DAY WITH SOME HIGHER PRESSURE BUILDING IN. TEMPERATURES WILL REMAIN AROUND 20 DEGREES BELOW NORMAL. THE LAST TIME IS WAS THIS COLD WAS BACK ON JANUARY 22 2014...THE HIGH TEMPERATURE IN ALBANY WAS ONLY 9 DEGREES WITH A LOW OF 6 DEGREES BELOW ZERO. LOOKING AT SIMILAR VALUES. WITH NORTHWEST FLOW ACROSS THE GREAT LAKES WOULD EXPECT MULTI BANDS ACROSS CENTRAL NEW YORK WHICH COULD MAY REACH INTO THE FAR WESTERN PORTION OF THE FORECAST AREA. YET ANOTHER NORTHERN STREAM SYSTEM WILL APPROACH LATE IN THE WEEK BRINGING MORE CHANCES FOR SNOW SHOWERS TO THE AREA. TEMPERATURES WILL MODERATE SOME IN THE SOUTHWEST FLOW AHEAD OF THE APPROACHING SYSTEM HOWEVER THEY WILL REMAIN WELL BELOW NORMAL. THE COLDEST AIR IS EXPECTED TO REMAIN TO OUR NORTH PASSING OVER EASTERN CANADA ITS IN WAKE AS WE HEAD INTO THE WEEKEND. COULD BE LOOKING AT MORE LAKE EFFECT IN THE WAKE OF THE SYSTEM. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... AS OF 1000 PM...CONDITIONS HAVE IMPROVED TO MVFR OR VFR AT ALL OF OUR TAF SITES. SHOWERS LOOK TO STILL IMPACT MAINLY KPOU AND KPSF WITH OCCASIONAL MVFR CONDITIONS THROUGH ABOUT MIDNIGHT. OTHERWISE...WITH THE POSSIBLE EXCEPTION OF KPSF...WE WILL HAVE MAINLY VFR CONDITIONS THROUGH MONDAY...MVFR AT KPSF. MONDAY AT KALB...AS A LAKE BAND OFF ONTARIO MIGHT IMPACT THE AIRPORT BETWEEN ABOUT 15Z-19Z. WE ASSIGNED A PROB30 FOR IFR SNOW SHOWERS (2SM -SHSN). AT KGFL AND KPSF WE ASSIGNED A VCSH AS THE THREAT OF MVFR SNOW SHOWERS WAS VERY LOW (ONLY ABOUT 25 PERCENT). AGAIN OUTSIDE OF ANY SNOW SHOWER ACTIVITY...THE MAJORITY OF THE TIME SHOULD BE VFR AT ALL TAF SITES MONDAY. AGAIN...A GUSTY WIND COULD CAUSE MECHANICAL TURBULENCE. OUTLOOK... MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. TUE: HIGH OPERATIONAL IMPACT. LIKELY SN. TUE NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN. WED: MODERATE OPERATIONAL IMPACT. BREEZY. CHANCE OF SHSN. WED NIGHT: LOW OPERATIONAL IMPACT. BREEZY. THU: NO OPERATIONAL IMPACT. NO SIG WX. THU NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN. FRI: NO OPERATIONAL IMPACT. NO SIG WX. && .HYDROLOGY... A COMPLEX STORM SYSTEM WITH MODERATE TO HEAVY QPF WILL MOVE ACROSS THE HSA THROUGH TODAY. MOST AREAS ARE FORECAST TO RECEIVE 1-2 INCHES OF LIQUID EQUIVALENT PRECIPITATION...WITH LOCALLY IN EXCESS OF TWO INCHES. THIS WILL ALLOW FOR SIGNIFICANT RISES ON RIVERS AND STREAMS ON SUNDAY...AS TEMPERATURES RISE ABOVE FREEZING BRIEFLY OVER THE ENTIRE REGION. ISOLATED MINOR FLOODING IS POSSIBLE AND PER COLLABORATION YESTERDAY WITH THE NERFC...THE HSA POINTS THAT GOES ABOVE ACTION STAGE ARE WILLIAMSTOWN /WILM3/...AND GRANVILLE /GVVN6/ AT THIS TIME. SINCE THE POTENTIAL OF WIDESPREAD MINOR FLOODING IS NOT EXPECTED...A FLOOD WATCH HAS NOT BEEN ISSUED AT THIS TIME. LAKE EFFECT SNOWFALL WILL IMPACT LOCATIONS NORTH AND WEST OF THE CAPITAL REGION TONIGHT THROUGH MONDAY IN THE WAKE OF A STRONG COLD FRONT. THEREAFTER...BITTER COLD WEATHER IS EXPECTED NEXT WEEK. SOME FREEZE UP ICE JAMS ARE POSSIBLE ACROSS THE SOUTHWESTERN ADIRONDACKS AND SOUTHERN VERMONT BY LATE IN THE WEEK. OTHERWISE...ICE WILL LIKELY DEVELOP AND INCREASE ACROSS RIVERS AND STREAMS. 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...LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 7 PM EST MONDAY FOR NYZ038>040-082. LAKE EFFECT SNOW ADVISORY UNTIL 9 AM EST MONDAY FOR NYZ032-033. MA...NONE. VT...NONE. && $$ SYNOPSIS...HWJIV/BGM NEAR TERM...HWJIV SHORT TERM...BGM LONG TERM...HWJIV AVIATION...HWJIV HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS TAUNTON MA
908 PM EST SUN JAN 4 2015 .SYNOPSIS... MILDER AIR THIS AFTERNOON WILL CONTINUE THIS EVENING AHEAD OF AN APPROACHING COLD. THE FRONT WILL DEVELOP SOME SHOWERS WITH LOCALLY HEAVY RAIN THIS EVENING FOLLOWED BY BLUSTERY AND MUCH COLDER WEATHER TOMORROW WITH A FEW SNOW SHOWERS POSSIBLE. WEAK LOW PRESSURE MAY BRING A PERIOD OF LIGHT SNOW TUE. AN ARCTIC FRONT MAY BE ACCOMPANIED BY A FEW SNOW SHOWERS AND SQUALLS WED FOLLOWED BY BLUSTERY AND BITTER COLD WEATHER WED NIGHT INTO THU. MORE SNOW SHOWERS ARE POSSIBLE THU NIGHT INTO FRI...THEN MAINLY DRY CONDITIONS INTO NEXT WEEKEND WITH BELOW NORMAL TEMPS. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 9 PM UPDATE... ONLY CHANGE WITH THIS FORECAST UPDATE IS TO EXPAND THE AREA OF HEAVY SHOWERS ACROSS EASTERN CT-RI AND EASTERN MA PER LATEST RADAR TRENDS. 00Z OBSERVED SOUNDING FROM OKX INDICATES SOME STEEP MID LEVEL LAPSE RATES FROM 750 MB TO ABOUT 600 MB. THIS WILL ENHANCE RAINFALL RATES BUT PROBABLY NOT SUFFICIENT FOR THUNDER. BRIEF HEAVY DOWNPOURS AS APPROACHING FRONTAL BOUNDARY IS ACTING ON PWATS GREATER THAN 1 INCH ALONG WITH MID LEVEL INSTABILITY MENTIONED ABOVE. NOT EXPECTING ANY SIGNIFICANT OR WIDESPREAD URBAN FLOODING AS BAND OF SHOWERS WILL MOVE OFFSHORE BY MIDNIGHT. REMAINDER OF THE FORECAST IS ON TRACK. EARLIER DISCUSSION BELOW. ----------------------------------------------------------------- NEXT AREA OF SHOWERS ARE DEVELOPING ACROSS LONG ISLAND AND MID ATLC COAST AND EXPECT SHOWERS TO EXPAND ACROSS SE HALF SNE THROUGH MIDNIGHT AS AREA OF LOW LEVEL FGEN DEVELOPS ASSOCD WITH FRONTAL WAVE. GENERALLY FOLLOWED HRRR WHICH HAS RAIN DEVELOPING BY 02Z IN THE EAST EXITING OUTER CAPE/ISLANDS AROUND 06Z. GENERALLY AROUND 0.25" RAIN EXPECTED RI AND SE MA WITH LOCALLY UP TO 0.50" CAPE/ISLANDS. EXTENDED THE DENSE FOG ADVISORY UNTIL 10 PM FOR CT VALLEY AND PORTIONS OF THE S COAST. LOW LEVEL COLD AIR HANGING TOUGH IN THE CT VALLEY BUT WILL EVENTUALLY MIX OUT WITH RISING TEMPS AS COLD FRONT APPROACHES WHICH WILL ALLOW FOR IMPROVING VSBYS. DROPPED THE WIND ADVISORY FOR THE S COAST. DESPITE CORE OF LOW LEVEL JET ACROSS SE NEW ENG THROUGH 03Z...VERY STRONG SFC INVERSION WILL PREVENT STRONG WINDS FROM REACHING THE GROUND. WITH NO CONVECTION EXPECTED IT IS UNLIKELY WIND GUSTS WILL REACH ADVISORY CRITERIA. APPEARS THAT THE FRONT WILL PASS FROM WEST TO EAST BEGINNING AROUND 06Z. AS THE FRONT PASSES THROUGH COLD AIR ADVECTION WILL PUSH THROUGH DROPPING TEMPS THROUGH THE REMAINDER OF THE NIGHT INTO THE MORNING HOURS. WE COULD ALSO SEE WIND GUSTS BEGIN TO INCREASE ACROSS THE INTERIOR AFTER 09Z BEHIND THE FRONT. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... TOMORROW... COLD FRONT SHOULD PASS THROUGH THE AREA TOMORROW AS COLD AIR ADVECTION CONTINUES TO STREAM INTO THE REGION. IN FACT HIGH TEMPS MAY BE REACHED IN THE MORNING AS TEMPS WILL BE DROPPING OR REMAINING STEADY THROUGH THE DAY. AS MENTIONED BEFORE...BEHIND THE FRONT WILL BE GOOD MOMENTUM TRANSFER AND THUS WE COULD SEE STRONG WIND GUSTS. BELIEVE THE PEAK WILL BE CLOSE TO TOMORROW MORNING AS LAPSE RAPES STEEPEN AND WINDS ARE MORE WESTERLY. GUSTS COULD REACH CLOSE TO 45- 50 MPH ESP ACROSS THE HIGHER TERRAIN AND NORTH OF THE CT/RI/MA BORDER. HELD OFF ON A WIND ADV FOR NOW BUT ONE MAY BE WARRANTED IN THE FUTURE. SECONDARY SHORTWAVE WILL MOVE THROUGH THE FLOW TOMORROW PUSHING A BOUNDARY OR A SECONDARY FRONT FROM THE NORTH. THIS BOUNDARY MAY ALLOW FOR SOME SNOW SHOWERS OR EVEN SOME SNOW SQUALLS TO DEVELOP. EVEN THOUGH WESTERLY WINDS TEND TO DRY THE ATMOSPHERE OUT GUIDANCE DOES SHOW LOW LEVEL MOISTURE IN THE 0-2KM LEVEL AND WITH NEGATIVE THETA-E LAPSE RATES AND SOME CONVERGENCE DECIDED IT WAS ENOUGH TO ADD POPS INTO THE FORECAST. CONFIDENCE ALSO IS INCREASED PER BTV LOCAL 4KM WRF MODEL SNOW SQUALL PARAMETER. IT SHOWS AT LEAST 1.0 TO EVEN 2.0 OVER A PORTION OF SOUTHERN NEW ENGLAND TOMORROW. IF THESE SNOW SQUALLS DO DEVELOP THEN THEY COULD DROP A QUICK INCH OF SNOW AND REDUCE VISIBILITIES. MOTORISTS SHOULD BE AWARE OF THIS POTENTIAL ESP IF THEY DEVELOP DURING THE EVENING COMMUTE. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * A PERIOD OF LIGHT SNOW TUE WITH MINOR ACCUM POSSIBLE * SCT SNOW SHOWERS AND A FEW SQUALLS POSSIBLE WED WITH ARCTIC FRONT * DANGEROUSLY COLD WIND CHILLS WED NIGHT INTO THU MORNING * MODERATION IN TEMPS INTO THE WEEKEND BUT REMAINING BELOW NORMAL OVERVIEW... DESPITE +PNA PATTERN WITH LACK OF HIGH LATITUDE BLOCKING DOWNSTREAM...-EPO PATTERN WITH STRONG E PACIFIC RIDGE WILL LEAD TO DEEP TROF ACROSS EASTERN CANADA TO THE GT LAKES WITH CROSS POLAR FLOW LEADING TO UNSEASONABLE COLD REGIME FOR MUCH OF THE EXTENDED PERIOD. HOWEVER...WHILE THERE WILL BE A FEW CHANCES FOR SNOW...NO APPRECIABLE STORMS ON THE HORIZON AS DOMINANT NORTHERN STREAM WILL KEEP MOISTURE LACKING ACROSS THE NE AS SUBTROPICAL MOISTURE REMAINS SUPPRESSED WELL TO THE SOUTH. A SERIES OF SHORTWAVES WILL BE ROTATING AROUND THE UPPER TROF...BRINGING A CHANCE OF LIGHT SNOW TUE WITH MORE AMPLIFIED SHORTWAVE DELIVERING PURE ARCTIC AIRMASS INTO SNE WED NIGHT/THU WHICH MAY BE PRECEDED BY SNOW SQUALLS WED ALONG THE ARCTIC FRONT. YET ANOTHER SHORTWAVE FOLLOWS FOR THE END OF THE WEEK. SOME MODERATION IN TEMPS INTO THE WEEKEND BUT REMAINING BELOW NORMAL. MON NIGHT... LEFTOVER SNOW SHOWERS POSSIBLE NEAR THE SOUTH COAST IN THE EVENING AS WEAK SHORTWAVE DEPARTS...OTHERWISE EXPECT CLEARING SKIES. BLUSTERY NW WINDS IN THE EVENING WILL DIMINISH OVERNIGHT AS SFC RIDGE BUILDS INTO THE REGION. TUE INTO TUE NIGHT... FAST MOVING LOW AMPLITUDE SHORTWAVE FROM THE LAKES MOVES ACROSS THE REGION. MODELS INDICATE WEAK CLIPPER LOW MOVING OFF MID ATLC COAST TUE AFTERNOON. DEEPENING MOISTURE IN THE COLUMN AND WEAK SYNOPTIC FORCING WILL LEAD TO LIGHT SNOW DEVELOPING ACROSS THE REGION DURING THE MORNING THEN MOVING OUT TUE EVENING. LOW PRES NOT REALLY DEVELOPING UNTIL IT IS WELL OFFSHORE AND ABSOLUTE MOISTURE IS LACKING WITH PWATS LESS THAN 0.2" SO NOT EXPECTING MUCH ACCUM...MAYBE 1-2" ESPECIALLY SOUTH OF THE MASS PIKE. WEDNESDAY... ARCTIC FRONT WILL PUSH S ACROSS SNE DURING THE AFTERNOON AS MID LEVEL SHORTWAVE SWINGS THROUGH. THERE ARE STRONG SIGNALS IN PLACE FOR SCT SNOW SHOWERS AND LOCALLY HEAVY SNOW SQUALLS DEVELOPING ALONG THE FRONT. GOOD MOISTURE IN THE LOW LEVELS COMBINED WITH LOW LEVEL CONVERGENCE...A SHORTWAVE AND LOW LEVEL INSTABILITY WITH VERY STEEP LAPSE RATES IN PLACE SUGGEST THE POTENTIAL FOR SOME HEAVIER SNOW SQUALLS. BECOMING WINDY AND MUCH COLDER BEHIND THE FRONT AS COLD ADVECTION INCREASES WITH GUSTS TO 30-40 MPH AND TEMPS FALLING INTO THE TEENS BY EVENING. WED NIGHT AND THU... CORE OF COLDEST AIR WILL MOVE INTO THE REGION WED NIGHT FROM STRONG CAA ON GUSTY NW WINDS WITH 925 MB TEMPS DOWN TO -24 TO -28C. RAW MODEL TEMPS FROM GFS/ECMWF AND NAM DROP BELOW ZERO FOR MUCH OF SNE WITH EXCEPTION OF IMMEDIATE S COAST AND CAPE/ISLANDS. COOLING IS THROUGH PURE ADVECTION AND THERE WILL LIKELY BE A FRESH SNOW COVER SO THESE TEMPS SHOULD BE REALIZED. BOS/PVD WILL LIKELY FALL TO NEAR ZERO WITH SUBZERO TEMPS IN THE INTERIOR. GUSTY NW WINDS WILL RESULT IN DANGEROUSLY COLD WIND CHILLS OF -15 TO -30 LATE WED NIGHT INTO THU MORNING. WIND CHILL HEADLINES WILL LIKELY BE NEEDED FOR MOST OF SNE. TEMPS WILL MODERATE THU INTO THE TEENS FOR MOST LOCATIONS AS CORE OF COLDEST QUICKLY MOVES OUT FAIRLY QUICKLY WITH 925 MB TEMPS INCREASING AROUND10C DURING THU. THU NIGHT AND FRI... NEXT SHORTWAVE APPROACHES AND MAY BRING ANOTHER ROUND OF SNOW SHOWERS. SNOW SQUALLS POSSIBLE FRI WITH NEXT FRONT? ALSO...OCEAN EFFECT SNOW ON SW FLOW IS POSSIBLE ALONG THE S COAST THU NIGHT AND FRI MORNING GIVEN COLD AIR ALOFT AND GOOD LOW LEVEL INSTABILITY OVER THE WATER. SOMETHING TO WATCH FOR LATER FORECASTS. SAT AND SUN... TEMPS MODERATE BUT STILL BELOW NORMAL. LOOKS DRY SAT WITH HIGH PRES IN CONTROL...THEN WILL HAVE TO WATCH POSSIBLE INVERTED TROF OF COASTAL LOW PRES FOR SUNDAY. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TOMORROW/...MODERATE CONFIDENCE 9 PM UPDATE... NO MAJOR CHANGES TO 00Z TAFS. HEAVY SHOWERS WILL BE FOCUSED ACROSS EASTERN CT-RI AND SOUTHEAST MA THEN MOVING OFFSHORE BY MIDNIGHT. EARLIER DISCUSSION BELOW. ------------------------------------------------------------------ TONIGHT...RISK OF SHOWERS /LOCALLY HEAVY/ MAINLY SE NEW ENG TIL ABOUT 04-06Z. IFR/MVFR IMPROVING TO VFR AFTER 06Z. GUSTY S COASTAL SW WINDS SHIFT TO W BY 06Z WITH GUSTS TO 35-40 KT DEVELOPING TOWARD DAYBREAK...ESPECIALLY NORTH OF THE CT/RI/MA BORDER AND ACROSS HIGHER ELEVATION. TOMORROW...ANTICIPATE VFR CONDITIONS BY 12Z ACROSS THE REGION. GUSTY WNW WINDS NEAR 45 KTS WILL BEGIN TO DROP THROUGHOUT THE DAY TO ABOUT 20-25KTS. ONLY ISSUE IS THE POTENTIAL FOR SNOW SQUALLS FROM NORTH TO SOUTH BY THE AFTERNOON. THIS MAY LIMIT VSBYS AND DROP CIGS VERY QUICKLY. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF ESP IN DENSE FOG DISSIPATION. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF ESP IN DENSE FOG DISSIPATION. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...MODERATE CONFIDENCE. MON NIGHT...VFR. GUSTY NW WINDS 25-30 KT IN THE EVENING. TUE...LOWERING TO MVFR AS LIGHT SNOW MOVES ACROSS THE REGION. LOW PROB FOR IFR. WED...MOSTLY VFR CIGS...BUT BRIEF PERIOD OF MVFR/IFR POSSIBLE IN LOCALLY HEAVY SNOW SQUALLS ALONG THE ARCTIC FRONT WED AFTERNOON. GUSTY NW WINDS TO 30-35 KT DEVELOPING IN THE AFTERNOON AND CONTINUING INTO WED NIGHT. THU...VFR. DIMINISHING WIND THU NIGHT AND FRI...AREAS OF MVFR DEVELOPING IN SCT SNOW SHOWERS. OCEAN EFFECT SNOW POSSIBLE ALONG THE S COAST. GUSTY SW WINDS DEVELOPING LATE THU NIGHT AND FRI. GUSTS TO 30-35 KT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY/...MODERATE TO HIGH CONFIDENCE. 9 PM UPDATE... NO MAJOR CHANGES FROM PREVIOUS FORECAST. HEAVY SHOWERS WILL IMPACT RI AND SOUTHERN MA WATERS THRU MIDNIGHT THEN OFFSHORE. EARLIER DISCUSSION BELOW. -------------------------------------------------------------------- DENSE FOG ACROSS THE WATERS WILL REMAIN UNTIL AFTER MIDNIGHT. TONIGHT...LOW END SOUTHWEST GALES EARLY THIS EVENING AND THEN BECOMING NW TONIGHT AT GALE FORCE. SHOWERS LIMIT VSBY EARLY BUT THEN IMPROVING WITH THE WIND SHIFT. TOMORROW...STRONG CAA MOVING ACROSS THE RELATIVELY WARM WATERS WILL ALLOW FOR SEAS TO BUILD. WIND GUSTS WILL CONTINUE TO BE AT OR ABOVE 34KTS SO CONTINUE THE GALE WARNING. LOW PROB OF A QUICK SNOW SHOWERS ACROSS THE NEAR SHOWER WATERS TOMORROW AFTERNOON. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE. MON NIGHT...GALE FORCE NW WINDS WILL LIKELY CONTINUE INTO THE EVENING...ESPECIALLY E WATERS...THEN DIMINISHING OVERNIGHT AS HIGH PRES BUILDS IN. TUE...WINDS AND SEAS BELOW SCA. REDUCED VSBYS IN LIGHT SNOW. WED INTO THU...STRONG COLD ADVECTION WILL LIKELY RESULT IN ANOTHER PERIOD OF NW GALES LATE WED AND WED NIGHT...LINGERING INTO THU MORNING BEFORE WINDS BEGIN TO DIMINISH. MODERATE FREEZING SPRAY DEVELOPING WED NIGHT INTO THU AS ARCTIC AIR MOVES OVER THE WATERS. THU NIGHT AND FRI...ANOTHER PERIOD OF GALES LIKELY LATE THU NIGHT INTO FRI...ON SW FLOW. GUSTS TO 40 KT POSSIBLE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...DENSE FOG ADVISORY UNTIL 10 PM EST THIS EVENING FOR CTZ002. MA...DENSE FOG ADVISORY UNTIL 10 PM EST THIS EVENING FOR MAZ003-010- 011-022>024. RI...DENSE FOG ADVISORY UNTIL 10 PM EST THIS EVENING FOR RIZ006>008. MARINE...GALE WARNING UNTIL 6 PM EST MONDAY FOR ANZ231>235-237-250-251- 254>256. GALE WARNING FROM 3 AM TO 6 PM EST MONDAY FOR ANZ230-236. && $$ SYNOPSIS...KJC/DUNTEN NEAR TERM...KJC/NOCERA/DUNTEN SHORT TERM...DUNTEN LONG TERM...KJC AVIATION...KJC/NOCERA/DUNTEN MARINE...KJC/NOCERA/DUNTEN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
717 PM EST SUN JAN 4 2015 .SYNOPSIS... MILDER AIR THIS AFTERNOON WILL CONTINUE THIS EVENING AHEAD OF AN APPROACHING COLD. THE FRONT WILL DEVELOP SOME SHOWERS WITH LOCALLY HEAVY RAIN THIS EVENING FOLLOWED BY BLUSTERY AND MUCH COLDER WEATHER TOMORROW WITH A FEW SNOW SHOWERS POSSIBLE. WEAK LOW PRESSURE MAY BRING A PERIOD OF LIGHT SNOW TUE. AN ARCTIC FRONT MAY BE ACCOMPANIED BY A FEW SNOW SHOWERS AND SQUALLS WED FOLLOWED BY BLUSTERY AND BITTER COLD WEATHER WED NIGHT INTO THU. MORE SNOW SHOWERS ARE POSSIBLE THU NIGHT INTO FRI...THEN MAINLY DRY CONDITIONS INTO NEXT WEEKEND WITH BELOW NORMAL TEMPS. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 7 PM UPDATE... NEXT AREA OF SHOWERS ARE DEVELOPING ACROSS LONG ISLAND AND MID ATLC COAST AND EXPECT SHOWERS TO EXPAND ACROSS SE HALF SNE THROUGH MIDNIGHT AS AREA OF LOW LEVEL FGEN DEVELOPS ASSOCD WITH FRONTAL WAVE. GENERALLY FOLLOWED HRRR WHICH HAS RAIN DEVELOPING BY 02Z IN THE EAST EXITING OUTER CAPE/ISLANDS AROUND 06Z. GENERALLY AROUND 0.25" RAIN EXPECTED RI AND SE MA WITH LOCALLY UP TO 0.50" CAPE/ISLANDS. EXTENDED THE DENSE FOG ADVISORY UNTIL 10 PM FOR CT VALLEY AND PORTIONS OF THE S COAST. LOW LEVEL COLD AIR HANGING TOUGH IN THE CT VALLEY BUT WILL EVENTUALLY MIX OUT WITH RISING TEMPS AS COLD FRONT APPROACHES WHICH WILL ALLOW FOR IMPROVING VSBYS. DROPPED THE WIND ADVISORY FOR THE S COAST. DESPITE CORE OF LOW LEVEL JET ACROSS SE NEW ENG THROUGH 03Z...VERY STRONG SFC INVERSION WILL PREVENT STRONG WINDS FROM REACHING THE GROUND. WITH NO CONVECTION EXPECTED IT IS UNLIKELY WIND GUSTS WILL REACH ADVISORY CRITERIA. APPEARS THAT THE FRONT WILL PASS FROM WEST TO EAST BEGINNING AROUND 06Z. AS THE FRONT PASSES THROUGH COLD AIR ADVECTION WILL PUSH THROUGH DROPPING TEMPS THROUGH THE REMAINDER OF THE NIGHT INTO THE MORNING HOURS. WE COULD ALSO SEE WIND GUSTS BEGIN TO INCREASE ACROSS THE INTERIOR AFTER 09Z BEHIND THE FRONT. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... TOMORROW... COLD FRONT SHOULD PASS THROUGH THE AREA TOMORROW AS COLD AIR ADVECTION CONTINUES TO STREAM INTO THE REGION. IN FACT HIGH TEMPS MAY BE REACHED IN THE MORNING AS TEMPS WILL BE DROPPING OR REMAINING STEADY THROUGH THE DAY. AS MENTIONED BEFORE...BEHIND THE FRONT WILL BE GOOD MOMENTUM TRANSFER AND THUS WE COULD SEE STRONG WIND GUSTS. BELIEVE THE PEAK WILL BE CLOSE TO TOMORROW MORNING AS LAPSE RAPES STEEPEN AND WINDS ARE MORE WESTERLY. GUSTS COULD REACH CLOSE TO 45- 50 MPH ESP ACROSS THE HIGHER TERRAIN AND NORTH OF THE CT/RI/MA BORDER. HELD OFF ON A WIND ADV FOR NOW BUT ONE MAY BE WARRANTED IN THE FUTURE. SECONDARY SHORTWAVE WILL MOVE THROUGH THE FLOW TOMORROW PUSHING A BOUNDARY OR A SECONDARY FRONT FROM THE NORTH. THIS BOUNDARY MAY ALLOW FOR SOME SNOW SHOWERS OR EVEN SOME SNOW SQUALLS TO DEVELOP. EVEN THOUGH WESTERLY WINDS TEND TO DRY THE ATMOSPHERE OUT GUIDANCE DOES SHOW LOW LEVEL MOISTURE IN THE 0-2KM LEVEL AND WITH NEGATIVE THETA-E LAPSE RATES AND SOME CONVERGENCE DECIDED IT WAS ENOUGH TO ADD POPS INTO THE FORECAST. CONFIDENCE ALSO IS INCREASED PER BTV LOCAL 4KM WRF MODEL SNOW SQUALL PARAMETER. IT SHOWS AT LEAST 1.0 TO EVEN 2.0 OVER A PORTION OF SOUTHERN NEW ENGLAND TOMORROW. IF THESE SNOW SQUALLS DO DEVELOP THEN THEY COULD DROP A QUICK INCH OF SNOW AND REDUCE VISIBILITIES. MOTORISTS SHOULD BE AWARE OF THIS POTENTIAL ESP IF THEY DEVELOP DURING THE EVENING COMMUTE. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * A PERIOD OF LIGHT SNOW TUE WITH MINOR ACCUM POSSIBLE * SCT SNOW SHOWERS AND A FEW SQUALLS POSSIBLE WED WITH ARCTIC FRONT * DANGEROUSLY COLD WIND CHILLS WED NIGHT INTO THU MORNING * MODERATION IN TEMPS INTO THE WEEKEND BUT REMAINING BELOW NORMAL OVERVIEW... DESPITE +PNA PATTERN WITH LACK OF HIGH LATITUDE BLOCKING DOWNSTREAM...-EPO PATTERN WITH STRONG E PACIFIC RIDGE WILL LEAD TO DEEP TROF ACROSS EASTERN CANADA TO THE GT LAKES WITH CROSS POLAR FLOW LEADING TO UNSEASONABLE COLD REGIME FOR MUCH OF THE EXTENDED PERIOD. HOWEVER...WHILE THERE WILL BE A FEW CHANCES FOR SNOW...NO APPRECIABLE STORMS ON THE HORIZON AS DOMINANT NORTHERN STREAM WILL KEEP MOISTURE LACKING ACROSS THE NE AS SUBTROPICAL MOISTURE REMAINS SUPPRESSED WELL TO THE SOUTH. A SERIES OF SHORTWAVES WILL BE ROTATING AROUND THE UPPER TROF...BRINGING A CHANCE OF LIGHT SNOW TUE WITH MORE AMPLIFIED SHORTWAVE DELIVERING PURE ARCTIC AIRMASS INTO SNE WED NIGHT/THU WHICH MAY BE PRECEDED BY SNOW SQUALLS WED ALONG THE ARCTIC FRONT. YET ANOTHER SHORTWAVE FOLLOWS FOR THE END OF THE WEEK. SOME MODERATION IN TEMPS INTO THE WEEKEND BUT REMAINING BELOW NORMAL. MON NIGHT... LEFTOVER SNOW SHOWERS POSSIBLE NEAR THE SOUTH COAST IN THE EVENING AS WEAK SHORTWAVE DEPARTS...OTHERWISE EXPECT CLEARING SKIES. BLUSTERY NW WINDS IN THE EVENING WILL DIMINISH OVERNIGHT AS SFC RIDGE BUILDS INTO THE REGION. TUE INTO TUE NIGHT... FAST MOVING LOW AMPLITUDE SHORTWAVE FROM THE LAKES MOVES ACROSS THE REGION. MODELS INDICATE WEAK CLIPPER LOW MOVING OFF MID ATLC COAST TUE AFTERNOON. DEEPENING MOISTURE IN THE COLUMN AND WEAK SYNOPTIC FORCING WILL LEAD TO LIGHT SNOW DEVELOPING ACROSS THE REGION DURING THE MORNING THEN MOVING OUT TUE EVENING. LOW PRES NOT REALLY DEVELOPING UNTIL IT IS WELL OFFSHORE AND ABSOLUTE MOISTURE IS LACKING WITH PWATS LESS THAN 0.2" SO NOT EXPECTING MUCH ACCUM...MAYBE 1-2" ESPECIALLY SOUTH OF THE MASS PIKE. WEDNESDAY... ARCTIC FRONT WILL PUSH S ACROSS SNE DURING THE AFTERNOON AS MID LEVEL SHORTWAVE SWINGS THROUGH. THERE ARE STRONG SIGNALS IN PLACE FOR SCT SNOW SHOWERS AND LOCALLY HEAVY SNOW SQUALLS DEVELOPING ALONG THE FRONT. GOOD MOISTURE IN THE LOW LEVELS COMBINED WITH LOW LEVEL CONVERGENCE...A SHORTWAVE AND LOW LEVEL INSTABILITY WITH VERY STEEP LAPSE RATES IN PLACE SUGGEST THE POTENTIAL FOR SOME HEAVIER SNOW SQUALLS. BECOMING WINDY AND MUCH COLDER BEHIND THE FRONT AS COLD ADVECTION INCREASES WITH GUSTS TO 30-40 MPH AND TEMPS FALLING INTO THE TEENS BY EVENING. WED NIGHT AND THU... CORE OF COLDEST AIR WILL MOVE INTO THE REGION WED NIGHT FROM STRONG CAA ON GUSTY NW WINDS WITH 925 MB TEMPS DOWN TO -24 TO -28C. RAW MODEL TEMPS FROM GFS/ECMWF AND NAM DROP BELOW ZERO FOR MUCH OF SNE WITH EXCEPTION OF IMMEDIATE S COAST AND CAPE/ISLANDS. COOLING IS THROUGH PURE ADVECTION AND THERE WILL LIKELY BE A FRESH SNOW COVER SO THESE TEMPS SHOULD BE REALIZED. BOS/PVD WILL LIKELY FALL TO NEAR ZERO WITH SUBZERO TEMPS IN THE INTERIOR. GUSTY NW WINDS WILL RESULT IN DANGEROUSLY COLD WIND CHILLS OF -15 TO -30 LATE WED NIGHT INTO THU MORNING. WIND CHILL HEADLINES WILL LIKELY BE NEEDED FOR MOST OF SNE. TEMPS WILL MODERATE THU INTO THE TEENS FOR MOST LOCATIONS AS CORE OF COLDEST QUICKLY MOVES OUT FAIRLY QUICKLY WITH 925 MB TEMPS INCREASING AROUND10C DURING THU. THU NIGHT AND FRI... NEXT SHORTWAVE APPROACHES AND MAY BRING ANOTHER ROUND OF SNOW SHOWERS. SNOW SQUALLS POSSIBLE FRI WITH NEXT FRONT? ALSO...OCEAN EFFECT SNOW ON SW FLOW IS POSSIBLE ALONG THE S COAST THU NIGHT AND FRI MORNING GIVEN COLD AIR ALOFT AND GOOD LOW LEVEL INSTABILITY OVER THE WATER. SOMETHING TO WATCH FOR LATER FORECASTS. SAT AND SUN... TEMPS MODERATE BUT STILL BELOW NORMAL. LOOKS DRY SAT WITH HIGH PRES IN CONTROL...THEN WILL HAVE TO WATCH POSSIBLE INVERTED TROF OF COASTAL LOW PRES FOR SUNDAY. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TOMORROW/...MODERATE CONFIDENCE TONIGHT...RISK OF SHOWERS /LOCALLY HEAVY/ MAINLY SE NEW ENG TIL ABOUT 04-06Z. IFR/MVFR IMPROVING TO VFR AFTER 06Z. GUSTY S COASTAL SW WINDS SHIFT TO W BY 06Z WITH GUSTS TO 35-40 KT DEVELOPING TOWARD DAYBREAK...ESPECIALLY NORTH OF THE CT/RI/MA BORDER AND ACROSS HIGHER ELEVATION. TOMORROW...ANTICIPATE VFR CONDITIONS BY 12Z ACROSS THE REGION. GUSTY WNW WINDS NEAR 45 KTS WILL BEGIN TO DROP THROUGHOUT THE DAY TO ABOUT 20-25KTS. ONLY ISSUE IS THE POTENTIAL FOR SNOW SQUALLS FROM NORTH TO SOUTH BY THE AFTERNOON. THIS MAY LIMIT VSBYS AND DROP CIGS VERY QUICKLY. KBOS TERMINAL...MODERATE CONFIDENCE IN TAF ESP IN DENSE FOG DISSIPATION. KBDL TERMINAL...MODERATE CONFIDENCE IN TAF ESP IN DENSE FOG DISSIPATION. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...MODERATE CONFIDENCE. MON NIGHT...VFR. GUSTY NW WINDS 25-30 KT IN THE EVENING. TUE...LOWERING TO MVFR AS LIGHT SNOW MOVES ACROSS THE REGION. LOW PROB FOR IFR. WED...MOSTLY VFR CIGS...BUT BRIEF PERIOD OF MVFR/IFR POSSIBLE IN LOCALLY HEAVY SNOW SQUALLS ALONG THE ARCTIC FRONT WED AFTERNOON. GUSTY NW WINDS TO 30-35 KT DEVELOPING IN THE AFTERNOON AND CONTINUING INTO WED NIGHT. THU...VFR. DIMINISHING WIND THU NIGHT AND FRI...AREAS OF MVFR DEVELOPING IN SCT SNOW SHOWERS. OCEAN EFFECT SNOW POSSIBLE ALONG THE S COAST. GUSTY SW WINDS DEVELOPING LATE THU NIGHT AND FRI. GUSTS TO 30-35 KT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY/...MODERATE TO HIGH CONFIDENCE. DENSE FOG ACROSS THE WATERS WILL REMAIN UNTIL AFTER MIDNIGHT. TONIGHT...LOW END SOUTHWEST GALES EARLY THIS EVENING AND THEN BECOMING NW TONIGHT AT GALE FORCE. SHOWERS LIMIT VSBY EARLY BUT THEN IMPROVING WITH THE WIND SHIFT. TOMORROW...STRONG CAA MOVING ACROSS THE RELATIVELY WARM WATERS WILL ALLOW FOR SEAS TO BUILD. WIND GUSTS WILL CONTINUE TO BE AT OR ABOVE 34KTS SO CONTINUE THE GALE WARNING. LOW PROB OF A QUICK SNOW SHOWERS ACROSS THE NEAR SHOWER WATERS TOMORROW AFTERNOON. OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE. MON NIGHT...GALE FORCE NW WINDS WILL LIKELY CONTINUE INTO THE EVENING...ESPECIALLY E WATERS...THEN DIMINISHING OVERNIGHT AS HIGH PRES BUILDS IN. TUE...WINDS AND SEAS BELOW SCA. REDUCED VSBYS IN LIGHT SNOW. WED INTO THU...STRONG COLD ADVECTION WILL LIKELY RESULT IN ANOTHER PERIOD OF NW GALES LATE WED AND WED NIGHT...LINGERING INTO THU MORNING BEFORE WINDS BEGIN TO DIMINISH. MODERATE FREEZING SPRAY DEVELOPING WED NIGHT INTO THU AS ARCTIC AIR MOVES OVER THE WATERS. THU NIGHT AND FRI...ANOTHER PERIOD OF GALES LIKELY LATE THU NIGHT INTO FRI...ON SW FLOW. GUSTS TO 40 KT POSSIBLE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...DENSE FOG ADVISORY UNTIL 10 PM EST THIS EVENING FOR CTZ002. MA...DENSE FOG ADVISORY UNTIL 10 PM EST THIS EVENING FOR MAZ003-010- 011-022>024. RI...DENSE FOG ADVISORY UNTIL 10 PM EST THIS EVENING FOR RIZ006>008. MARINE...GALE WARNING UNTIL 6 PM EST MONDAY FOR ANZ231>235-237-250-251- 254>256. GALE WARNING FROM 3 AM TO 6 PM EST MONDAY FOR ANZ230-236. && $$ SYNOPSIS...KJC/DUNTEN NEAR TERM...KJC/DUNTEN SHORT TERM...DUNTEN LONG TERM...KJC AVIATION...KJC/DUNTEN MARINE...KJC/DUNTEN
AREA FORECAST DISCUSSION
NWS ALBANY NY
710 PM EST SUN JAN 4 2015 .SYNOPSIS... A STRONG COLD FRONT WILL MOVE ACROSS EASTERN NEW YORK AND WESTERN NEW ENGLAND TONIGHT WITH RAIN SHOWERS TRANSITIONING TO SNOW SHOWERS. BLUSTERY AND COLD CONDITIONS WILL OPEN THE WORK WEEK WITH LAKE EFFECT SNOW SHOWERS AND SQUALLS. && .NEAR TERM /THROUGH MONDAY/... AS OF 700 PM EST...A COLD FRONT WAS JUST TO THE WEST OF THE HUDSON VALLEY...AND WORK ACROSS THE HUDSON VALLEY EARLY THIS EVENING...AND TO THE EAST OF THE HUDSON VALLEY LATER THIS EVENING. THIS FRONT HAD BROKEN LINE OF RAIN SHOWERS ASSOCIATED WITH IT...AND THESE WILL WORK ACROSS THE REGION ALONG WITH PATCHY DRIZZLE. BEHIND THE FRONT...THE WIND WILL SHIFT TO THE WEST...GUST TO BETWEEN 20 AND 30 MPH INITIALLY. TEMPERATURES WILL FALL...BUT NOT ALL THAT MUCH. ACTUALLY...AS THE FRONT SCOURS OUT THE LOW LEVEL INVERSION...SOME TEMPERATURES MIGHT BRIEFLY SPIKE AS IT MOVES ON THROUGH...WITH A FEW SPOTS POSSIBLY TOUCHING 50 DEGREES BEFORE FALLING BACK THROUGH THE 40S INTO THE 30S LATER THIS EVENING. THE FLOW ACROSS LAKE ONTARIO WILL BECOME COLD ENOUGH FOR LAKE EFFECT SNOW SHOWERS...LATER THIS EVENING. INITIALLY THIS MIGHT BE A RAIN AND SNOW MIX...BUT QUICKLY GOING TO ALL SNOW. WE HAVE THE LAKE EFFECT ADVISORIES UP FOR THE CENTRAL MOHAWK VALLEY AND ADIRONDACKS. WE EXPECT 3 TO 6 INCHES ACROSS PORTIONS OF THIS REGION. THERE IS A CHANCE WE MIGHT UPGRADE TO A WARNING...SHOULD THE LAKE BAND BECOME ROBUST LATER ON THIS EVENING. OTHERWISE...AS THE COLD FRONT MOVES ON BY...THERE WILL PARTIAL CLEARING...ESPECIALLY TO THE LEE OF THE CATSKILLS. LATER OVERNIGHT...A SECONDARY TROUGH OR COLD WILL MOVE ON IN. THIS ONE WILL BRING THE REALLY COLD PUSH OF AIR ALONG WITH STRONG GUSTY WINDS...WITH GUSTS 30-45 MPH (JUST SHY OF WIND ADVISORY). BY MORNING LOOK FOR LOWS DOWN TO && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... LAKE EFFECT SNOW ADVISORY ISSUED FROM 7 PM SUNDAY TO 7 AM MONDAY FOR NORTHERN HERKIMER AND HAMILTON COUNTIES... ...LAKE EFFECT SNOW ADVISORY ISSUED FROM 4 AM MONDAY TO 7 PM MONDAY FOR SOUTHERN HERKIMER...FULTON AND MONTGOMERY COUNTIES. THE ADVISORIES ARE FOR SNOW AND BLOWING SNOW WITH GUSTY WINDS OF 35 TO 45 MPH. OUR CONFIDENCE WAS NOT GREAT ENOUGH TO ISSUE A WIND ADVISORY FOR PARTS OF THE REGION SUNDAY NIGHT...THOUGH A 3RD PERIOD ADVISORY MAY BE NEEDED FOR MONDAY...AS BETTER MOMENTUM TRANSFER IS EXPECTED...BUT FOR NOW WIDESPREAD 46-57 MPH WIND GUSTS ARE NOT ANTICIPATED FOR SUNDAY NIGHT INTO MONDAY. THIS WILL CONTINUE TO BE MONITORED. TONIGHT...COLD FRONT MOVES ACROSS THE REGION WITH STRONG LOW LEVEL COLD ADVECTION EXPECTED. WESTERLY UPSLOPE SNOW SHOWERS WILL INITIALLY IMPACT THE WRN DACKS AND SRN GREENS MTNS WITH MORE SCT RAIN AND SNOW SHOWER ACTIVITY AWAY FROM THESE AREAS. THE LATEST HIRES WRF AND 3-KM HRRR INDICATE A TRANSITION FROM THE WESTERLY UPSLOPE SNOW SHOWERS OVER THE WRN DACKS TO AN ORGANIZED SINGLE BAND. BUFKIT PROFILES JUST DOWNSTREAM OF LAKE ONTARIO INDICATED MODERATE INSTABILITY WITH AN INVERSION HEIGHT CLOSE TO 10 KFT. HOWEVER...THE BAND IS EXPECTED TO FORM AND QUICKLY TRANSITION S/SE WITH THE STRONG VEERING WIND PROFILE IN THE BOUNDARY LAYER. THE LOW LEVEL FLOW STARTS AT 260-270 DEGS AND THEN SHIFTS TO A 280 TO 290 DEG LOW-LEVEL TRAJECTORY. A QUICK BLAST OF HVY SNOW SHOWERS IS ANTICIPATED FOR THE WRN DACKS WITH 3 TO 6 INCHES OF SNOW WITH PERHAPS SOME 4 TO 8 INCH AMOUNTS JUST SOUTH OF OLD FORGE AND INLET. THE TRANSITORY BAND MOVES INTO SRN HERKIMER COUNTY...AND THE W-CNTRL MOHAWK VALLEY BTWN 4-7 AM. THE NAM AND HIRES WRF SHOW A MULTI-LAKE CONNECTION WITH MDT INSTABILITY CLASS AT KUCA BUFKIT PROFILE. THIS AREA MAY NEED AN UPGRADE LATER...BUT WE PUT THE ENTIRE W-CNTRL MOHAWK VALLEY CORRIDOR WAS ALSO PLACED IN A LAKE EFFECT SNOW ADVISORY FOR SNOW AND BLOWING SNOW. ADVISORY WIND LEVEL GUSTS WILL BE CLOSE WITH 35 TO 45 MPH GUSTS FORECASTED. LOWS WILL BE MUCH COLDER IN THE TEENS TO M20S WITH SOME SINGLE DIGITS OVER THE ADIRONDACK PARK...AND U20S OVER THE MID HUDSON VALLEY. MONDAY...THE BETTER PRESSURE RISES PASS NORTH OF ST LAWRENCE RIVER VALLEY AND NRN NY BTWN 12Z-18Z MON 8-10 HPA/6 HRS. THE ISALLOBARIC COUPLET IS IMPRESSIVE AS THE CYCLONE DEEPENS AND INTENSIFIES TO ABOUT 980 HPA OVER THE GULF OF ST LAWRENCE BY 12Z/MON. SOME SUSTAINED WESTERLY WINDS OF 15 TO 25 MPH WITH GUSTS 35 TO 45 MPH ARE EXPECTED. THE 10-M WINDS ON THE GFSMOS PRODUCT FOR KALB ARE IMPRESSIVE IN THE 18-24 KT SUSTAINED RANGE. THE BUFKIT MOMENTUM TRANSFER PROFILES SHOW 40 KTS WILL NEED TO MIXED FROM 2.5 KFT AGL FOR WIND ADVISORY CRITERIA TO BE MET. ANY WIND FLAGS WILL BE MONITORED BY LATER SHIFTS. IT DOES LOOK PLAUSIBLE THAT SOME LAKE EFFECT SHOWERS MAY SNEAK DOWN THE MOHAWK RIVER VALLEY INTO THE CAPITAL REGION AND NRN TACONICS. HIGH CHC AND LIKELY POPS WERE USED LATE MONDAY MORNING INTO THE PM FOR A COATING TO PERHAPS A HALF AN INCH OF SNOW. SOME OF THE UPSLOPE AREAS OF THE SRN GREENS IN THE SRN VT...TACONICS...AND NRN BERKS COULD GET AN INCH OR TWO OR SNOW. THE ADVISORY AREA HIGHLIGHTED WILL LIKELY RECEIVE 3 TO 6 INCHES WITH SOME ISOLATED 4 TO 8 INCH AMOUNTS. THE INVERSION HEIGHTS DO LOWER IN THE AFTERNOON...AND THE SHEAR INCREASES SO THE DOWNSTREAM TRAJECTORY WILL DECREASE. MAX TEMPS MAY BE IN THE MORNING...AND TEMPS MAY CONTINUE TO FALL SLOWLY IN THE AFTERNOON IN THE POTENT COLD ADVECTION REGIME...AS H850 TEMPS CRASH INTO THE -17C TO -22C RANGE ACROSS THE FCST AREA. DAYTIME HIGHS WILL BE IN THE M20S TO L30S FROM THE TRI CITIES SOUTH AND EAST...AND TEENS TO L20S NORTH AND WEST WITH SOME SINGLE NUMBERS OVER THE SRN DACKS. WIND CHILLS WILL RANGE FROM 10 BELOW TO 10 ABOVE ZERO. MONDAY NIGHT...LAKE EFFECT SNOW BAND LIFTS BACK NORTHWARD...AS THE FLOW BACKS WITH AN APPROACHING SHORT-WAVE/CLIPPER LOW FROM THE GREAT LAKES REGION AND MIDWEST. HIGH PRESSURE BRIEFLY BUILDS IN FROM QUEBEC WITH A VERY COLD NIGHT EXPECTED. THE WINDS SHOULD DIMINISH...AND FRIGID TEMPS ARE ANTICIPATED WITH LOWS BELOW ZERO OVER THE SRN DACKS...AND PARTS OF THE LAKE REGION REGION...AND ZERO TO 10 ABOVE IN MOST OTHER LOCATIONS WITH SOME LOWER TEENS IN THE CAPITAL DISTRICT AND MID HUDSON VALLEY. CLOUDS WILL INCREASE IN THE FRIGID AIR MASS WITH THE BETTER CHANCE FOR LIGHT SNOW AND SCT SNOW SHOWERS ON TUE. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... VERY COLD TEMPERATURES AND ACTIVE WEATHER THIS WEEK...WITH THE COLDEST TEMPERATURES OF THE WINTER EXPECTED WEDNESDAY NIGHT AND THURSDAY WITH LIFE-THREATENING WIND CHILLS POSSIBLE. A QUICK MOVING NORTHERN STREAM CLIPPER SYSTEM WILL BRING A PERIOD OF LIGHT SNOW TO THE AREA TUESDAY. THIS SYSTEM IS EXPECTED TO PASS OVER THE OHIO VALLEY AND MOVE OFF THE DELMARVA. IT WILL HAVE LIMITED MOISTURE BUT GOOD FORCING. LOOKING AT HIGH RATIO SNOWFALL. AT THIS TIME EXPECT BELOW ADVISORY LEVEL ACCUMULATIONS. HIGHS WILL BE AROUND 10 DEGREES BELOW NORMAL. THE NEXT QUICK MOVING LOW PRESSURE SYSTEM AND NORTHERN STREAM SHORT WAVE WILL BE IN ITS HEELS. WILL HAVE CONTINUING CHANCES FOR SNOW SHOWERS TUESDAY NIGHT WITH SOME LAKE EFFECT/ENHANCEMENT INTO THE WESTERN ADIRONDACKS. EXPECT SNOW SHOWERS AND POSSIBLY SNOW SQUALLS AS THE ARCTIC BOUNDARY APPROACHES AND MOVES THROUGH WEDNESDAY. THIS SYSTEM/FRONT WILL BE THE ONE THAT OPENS THE DOOR TO THE ARCTIC AIRMASS WITH ITS PASSAGE STRONG COLD AIR ADVECTION WILL BEGIN. 850 MB TEMPERATURES ARE MODELED TO DROP TO -25 TO -30 DEGREES CELSIUS ACROSS THE FORECAST AREA WEDNESDAY NIGHT. SURFACE TEMPERATURES ARE FORECAST TO PLUMMET RANGING FROM AROUND 1 DEGREES TO AROUND 20 DEGREES BELOW ZERO...AROUND 20 DEGREES BELOW NORMAL. IN ADDITION...THE PRESSURE GRADIENT ACROSS THE REGION WILL BE TIGHT BETWEEN THE DEPARTING LOW PRESSURE SYSTEM AND AN ADVANCING HIGH RESULTING IN BRISK AND GUSTY NORTHWEST WINDS. THE COMBINATION OF THE BITTER TEMPERATURES AND BRISK WINDS WILL RESULT IN DANGEROUS TO LIFE-THREATENING WIND CHILL VALUES WEDNESDAY NIGHT INTO THURSDAY MORNING. WILL KEEP MENTION IN THE HAZARDOUS WEATHER OUTLOOK. THURSDAY WILL BE A FRIGID DAY WITH SOME HIGHER PRESSURE BUILDING IN. TEMPERATURES WILL REMAIN AROUND 20 DEGREES BELOW NORMAL. THE LAST TIME IS WAS THIS COLD WAS BACK ON JANUARY 22 2014...THE HIGH TEMPERATURE IN ALBANY WAS ONLY 9 DEGREES WITH A LOW OF 6 DEGREES BELOW ZERO. LOOKING AT SIMILAR VALUES. WITH NORTHWEST FLOW ACROSS THE GREAT LAKES WOULD EXPECT MULTI BANDS ACROSS CENTRAL NEW YORK WHICH COULD MAY REACH INTO THE FAR WESTERN PORTION OF THE FORECAST AREA. YET ANOTHER NORTHERN STREAM SYSTEM WILL APPROACH LATE IN THE WEEK BRINGING MORE CHANCES FOR SNOW SHOWERS TO THE AREA. TEMPERATURES WILL MODERATE SOME IN THE SOUTHWEST FLOW AHEAD OF THE APPROACHING SYSTEM HOWEVER THEY WILL REMAIN WELL BELOW NORMAL. THE COLDEST AIR IS EXPECTED TO REMAIN TO OUR NORTH PASSING OVER EASTERN CANADA ITS IN WAKE AS WE HEAD INTO THE WEEKEND. COULD BE LOOKING AT MORE LAKE EFFECT IN THE WAKE OF THE SYSTEM. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... FLYING CONDITIONS WILL IMPROVE THIS EVENING AFTER INITIALLY STARTING OUT AS IFR IN MOST CASES. A COLD FRONT WILL CROSS THE TERMINALS BETWEEN 02Z TO 04Z (FIRST AT KALB AND LAST AT KPSF). AFTER THE FRONT MOVES THROUGH...THE WIND WILL SHIFT TO THE WEST GUSTING TO AROUND 20KTS OR SO AT MOST OF THE TAF SITES. THIS WILL SERVE TO SCOUR OUT THE LOW CLOUDS AND FOG...WITH MOST OF THE TAF SITES TRANSITIONING FROM IFR TO MVFR AND EVENTUALLY VFR. THE ONLY EXCEPTION WOULD BE KPSF...WITH CIGS LIKELY TO HOLD IN THE MVFR RANGE UNTIL MONDAY MORNING. A SECONDARY PUSH OF COLD AIR IS FORECAST TO REACH THE TAF SITES AROUND 12Z...PRODUCING WIND GUSTS TO 30KTS OR HIGHER (ESPECIALLY AT KPSF AND KALB). THIS WILL HELP FURTHER CLEAR OUT THE TAFS OF ANY LINGERING MVFR (KPSF) BUT THERE WILL STILL BE VFR CIGS. MIDDAY...IT LOOKS AS IF THE FLOW MIGHT BE RIGHT FOR A LAKE EFFECT SNOW BAND OFF ONTARIO TO FUNNEL DOWN TO THE MOHAWK VALLEY...SO SNOW SHOWERS COULD IMPACT MAINLY KALB (POSSIBLY KPSF). FOR NOW...WE ASSIGNED A PROB30 FOR THE POSSIBILITY OF IFR SNOW SHOWERS (2 -SHSN) FROM 15Z TO 19Z AT KALB ONLY WHERE THE THREAT IS HIGHEST (25-49 PERCENT). AT THE OTHER TAF SITES JUST WENT VCSH (LESS THAN A 25 PERCENT CHANCE OF SNOW SHOWERS REDUCING CONDITIONS TO IFR). THE ONLY EXCEPTION WAS KPOU WHERE THE THREAT WAS EVEN LOWER THAN 25 PERCENT SO NO VCSH THERE. OUTSIDE OF SNOW SHOWER ACTIVITY...THE MAJORITY OF THE TIME SHOULD BE VFR AT ALL TAF SITES MONDAY. AGAIN...A GUSTY WIND COULD CAUSE MECHANICAL TURBULENCE. OUTLOOK... MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. TUE: HIGH OPERATIONAL IMPACT. LIKELY SN. TUE NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN. WED: MODERATE OPERATIONAL IMPACT. BREEZY. CHANCE OF SHSN. WED NIGHT: LOW OPERATIONAL IMPACT. BREEZY. THU: NO OPERATIONAL IMPACT. NO SIG WX. THU NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN. FRI: NO OPERATIONAL IMPACT. NO SIG WX. && .HYDROLOGY... A COMPLEX STORM SYSTEM WITH MODERATE TO HEAVY QPF WILL MOVE ACROSS THE HSA THROUGH TODAY. MOST AREAS ARE FORECAST TO RECEIVE 1-2 INCHES OF LIQUID EQUIVALENT PRECIPITATION...WITH LOCALLY IN EXCESS OF TWO INCHES. THIS WILL ALLOW FOR SIGNIFICANT RISES ON RIVERS AND STREAMS ON SUNDAY...AS TEMPERATURES RISE ABOVE FREEZING BRIEFLY OVER THE ENTIRE REGION. ISOLATED MINOR FLOODING IS POSSIBLE AND PER COLLABORATION YESTERDAY WITH THE NERFC...THE HSA POINTS THAT GOES ABOVE ACTION STAGE ARE WILLIAMSTOWN /WILM3/...AND GRANVILLE /GVVN6/ AT THIS TIME. SINCE THE POTENTIAL OF WIDESPREAD MINOR FLOODING IS NOT EXPECTED...A FLOOD WATCH HAS NOT BEEN ISSUED AT THIS TIME. LAKE EFFECT SNOWFALL WILL IMPACT LOCATIONS NORTH AND WEST OF THE CAPITAL REGION TONIGHT THROUGH MONDAY IN THE WAKE OF A STRONG COLD FRONT. THEREAFTER...BITTER COLD WEATHER IS EXPECTED NEXT WEEK. SOME FREEZE UP ICE JAMS ARE POSSIBLE ACROSS THE SOUTHWESTERN ADIRONDACKS AND SOUTHERN VERMONT BY LATE IN THE WEEK. OTHERWISE...ICE WILL LIKELY DEVELOP AND INCREASE ACROSS RIVERS AND STREAMS. 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...LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 7 PM EST MONDAY FOR NYZ038>040-082. LAKE EFFECT SNOW ADVISORY UNTIL 9 AM EST MONDAY FOR NYZ032-033. MA...NONE. VT...NONE. && $$ SYNOPSIS...BGM/WASULA NEAR TERM...HWJIV SHORT TERM...BGM/WASULA LONG TERM...HWJIV AVIATION...HWJIV HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NWS KEY WEST FL
915 PM EST SUN JAN 4 2015 .DISCUSSION...IN THE MIDDLE AND UPPER LEVELS...(700-200 MB). AS OF 900 PM...A BURGEONING EXPANSIVE FULL LATITUDINAL POLAR TROUGH IS IN PLACE FROM THE ROCKY MOUNTAINS WITH THE EASTERN FLANK NOW APPROACHING THE APPALACHIAN MOUNTAIN CHAIN. THIS AMPLIFYING LONGWAVE PATTERN IN COMBINATION WITH A DEEP AND WARM ANTICYCLONE CENTERED OVER CENTRAL CUBA IS RESULTING IN AVERAGE 100 KNOT SOUTHWESTERLIES AT 250 MB RACING FROM CENTRAL OLD MEXICO NORTHEASTWARD TO ACROSS THE SOUTHEASTERN STATES EXITING THE CONUS OFF OF THE MID ATLANTIC STATES. AT THE SURFACE AND IN THE LOWER TO MID LEVELS...(SURFACE TO 700 MB)...AS OF 900 PM...A 1042 MB ARCTIC SURFACE RIDGE IS IN PLACE ACROSS THE NORTHERN AND CENTRAL PLAINS. A COLD FRONT IS IN PLACE FROM EASTERN NEW YORK SOUTH SOUTHWESTWARD TO THE FLORIDA PANHANDLE THENCE INTO THE CENTRAL GULF OF MEXICO. THENCE...THE 00Z EVENING SOUNDING ILLUSTRATED A GENTLE TO OCCASIONALLY MODERATE EAST TO SOUTHEASTERLY FLOW FROM THE SURFACE TO 850 MB. BOUNDARY LAYER MOISTURE WAS CONFINED TO BELOW 850 MB...WITH TOTAL COLUMNAR PWAT AOA 1.15 INCHES. .CURRENTLY...SKIES ARE MOSTLY CLEAR TO PARTLY CLOUDY ACROSS THE KEYS ISLAND CHAIN AND ADJOINING WATERS. TEMPERATURES ACROSS THE ISLANDS ARE IN THE WARM UPPER 70S WITH EXCEPTIONALLY HUMID DEWPOINTS FOR EARLY JANUARY IN THE LOWER TO MID 70S. RADAR DOES NOT DETECT ANY SHOWERS ACROSS THE SERVICE AREA. C-MAN STATIONS ARE REGISTERING MAINLY EAST WINDS NEAR 10 KNOTS WITH ISLAND SENSORS BETWEEN 5 AND 10 MPH. .FORECASTS...OVERNIGHT...THE SURFACE COLD FRONT TO THE NORTHWEST SHOULD CREEP DOWN TOWARDS CENTRAL FLORIDA BY MORNING. GENTLE EAST WINDS WILL REMAIN IN PLACE ACROSS ALL WATERS EXCEPT GENTLE TO MODERATE WINDS CAN STILL BE EXPECTED ACROSS THE OUTER FLORIDA STRAITS. THE LATEST HRRR SEEMS TO HAVE A HANDLE ON THIS IDEA...EXCEPT THERE IS SOME BACKING OF THE WINDS ACROSS THE SHALLOW WATERS NORTH OF THE KEYS. ALTHOUGH MOISTURE REMAINS QUITE LIMITED IN THE BOUNDARY LAYER...AVAILABLE MODEL FORECAST SOUNDINGS ILLUSTRATE PWAT(PRECIPITABLE WATER) BETWEEN 1.00 AND 1.25 INCHES...WHICH COULD SUPPORT VERY LIGHT SHOWERS AT BEST. AM TEMPTED TO REMOVE THE CHANCE FOR RAIN BUT VERY WEAK LOWER LEVEL CONVERGENCE MAY SUPPORT A LIGHT SHOWER SOMEWHERE OVER THE KEYS ISLAND CHAIN. THIS WAS HINTED IN THE WRF RUN. FORECAST IS ON TRACK AND NO CHANGES WILL BE MADE. && .MARINE...OVERNIGHT...GENTLE WINDS ACROSS ALL WATERS EXCEPT GENTLE TO MODERATE ACROSS THE OUTER FLORIDA STRAITS. NO HEADLINES OR SCA ADVISORIES THRU 12Z. PLEASE STAY TUNED TO THE NEXT MARINE FORECAST OVERNIGHT AND DURING MONDAY FOR CHANGES THIS WEEK. && .AVIATION... VFR CONDITIONS WILL PREVAIL AT EYW AND MTH TONIGHT AND MONDAY. SHORT-LIVED...MVFR CEILINGS...BASED AT AROUND 2500 FEET...ARE LIKELY AT EYW AND MTH TONIGHT INTO EARLY MONDAY MORNING. THESE MVFR CEILINGS WILL NOT BE INCLUDED IN THE TERMINAL FORECASTS DUE TO THE BRIEF NATURE OF OCCURRENCE. SUSTAINED EAST TO SOUTHEAST WINDS OF 10 TO 15 KNOTS EXPECTED FROM JUST OFF THE SURFACE TO ABOUT 3000 FEET. && .CLIMATE... THE LOW TEMPERATURE SO FAR TODAY AS KEY WEST INTERNATIONAL AIRPORT IS 77 DEGREES. THE TEMPERATURE AT KEY WEST INTERNATIONAL AIRPORT SHOULD NOT FALL BELOW 76 DEGREES BY MIDNIGHT TONIGHT...WHICH WOULD BREAK THE DAILY RECORD FOR WARMEST MINIMUM TEMPERATURE EVER MEASURED IN KEY WEST ON JANUARY 4TH. THE CURRENT RECORD FOR WARMEST MINIMUM TEMPERATURE RECORDED IN KEY WEST ON JANUARY 4TH IS 75 DEGREES... INITIALLY ESTABLISHED IN 1973 AND LAST GAUGED IN 2007. TEMPERATURE RECORDS AT KEY WEST DATE BACK TO 1872. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...NONE. GM...NONE. && $$ PUBLIC/MARINE.........FUTTERMAN AVIATION/CLIMATE......BS DATA COLLECTION.......FLING VISIT US ON THE WEB AT WEATHER.GOV/KEY FOLLOW US ON FACEBOOK AND TWITTER AT... WWW.FACEBOOK.COM/NWSKEYWEST WWW.TWITTER.COM/NWSKEYWEST
AREA FORECAST DISCUSSION
NWS MIAMI FL
721 PM EST SUN JAN 4 2015 .UPDATE...IT SURE DOESN`T FEEL LIKE JANUARY! A DEWPOINT OF 72F AT THE OFFICE RIGHT NOW. THIS RATHER STEAMY AIRMASS ALONG WITH JUST SLIGHT CONVERGENCE IN SURFACE WINDS (SE WINDS ENCOUNTERING SW WINDS IN THE LAKE REGION) HAS ALLOWED FOR A BROKEN BAND OF MODERATE TO HEAVY SHOWERS TO DEVELOP FROM SOUTHEASTERN HENDRY COUNTY EXTENDING NORTHEAST TO LAKE OKEECHOBEE.THE LATEST RUN OF THE HRRR INITIALIZED WELL, DEPICTING SHOWER ACTIVITY ACROSS THIS REGION AND SHOWS THESE SHOWERS DECAYING THROUGH MIDNIGHT. THIS SEEMS REASONABLE WITH THE LOSS OF DAYTIME HEATING. SO THE ONLY UPDATE TO THE FORECAST WAS TO ADD THE ONGOING ISOLATED SHOWERS ACROSS THIS REGION FOR THE NEXT FEW HOURS. /GREGORIA && .PREV DISCUSSION... /ISSUED 654 PM EST SUN JAN 4 2015/ AVIATION... MAINLY VFR CONDITIONS TO PREVAIL THROUGH THE PERIOD. MAINLY LIGHT SOUTHERLY WINDS WILL TRANSITION EAST-SOUTHEASTERLY THROUGH THE NIGHT AS A COLD FRONT APPROACHES THE AREA FROM THE NORTH. FRONT SHOULD EASE INTO SOUTH FLORIDA TOWARD THE LAST FEW HOURS OF THIS TAF CYCLE TURNING WINDS AROUND TO THE NORTHEAST. A FEW SHOWERS MAY BRIEFLY AFFECT THE TAF SITES AS THE FRONT APPROACHES BUT COVERAGE SHOULD BE TOO SPARSE TO MENTION IN TAFS FOR NOW. MAIN CONCERN FOR FOG DEVELOPMENT WILL BE ACROSS THE NORTHWEST INTERIOR AND MAY BRIEFLY AFFECT KAPF. PLACED A TEMPO FOR MVFR VSBY FROM 09Z-13Z AS IT LOOKS LIKE BEST COVERAGE FOR FOG WILL REMAIN EAST OF KAPF. PREV DISCUSSION... /ISSUED 249 PM EST SUN JAN 4 2015/ SHORT TERM (TONIGHT THROUGH WEDNESDAY)... LARGE AND DEEP-LAYERED SUBTROPICAL HIGH PRESSURE EXTENDING FROM THE BAHAMAS ACROSS SOUTH FLORIDA WILL PERSIST THROUGH TUESDAY, THEN FINALLY GIVE WAY TO AMPLIFYING EASTERN U.S. TROUGH BY WEDNESDAY. THE RIDGE WILL KEEP THE STRONG/SEVERE TSTMS CURRENTLY OVER THE FLORIDA PANHANDLE FROM REACHING OUR PART OF THE STATE. THE COLD FRONT ASSOCIATED WITH THESE TSTMS WILL MOVE DOWN THE STATE TONIGHT, REACHING THE LAKE OKEECHOBEE AREA SHORTLY AFTER SUNRISE MONDAY. AHEAD OF THE FRONT, A FEW LIGHT SHOWERS (SIMILAR TO WHAT WE`RE SEEING THIS AFTERNOON) ARE NOT TOTALLY OUT OF THE QUESTION BUT NOT HIGH ENOUGH PROBABILITY (10%) TO INCLUDE IN FORECAST. AS IS TYPICAL WITH NIGHTTIME FRONTS NORTH OF LAKE OKEECHOBEE, PATCHY FOG IS EXPECTED AND COULD BE DENSE IN A FEW AREAS OF THE INTERIOR AND WEST. SHORT RANGE ENSEMBLE FORECASTS ARE NOT SHOWING HIGH PROBABILITIES OF DENSE FOG, BUT FEEL THIS IS UNDERDONE AND WE MAY END UP WITH AREAS OF FOG OVER THE EVERGLADES. THIS IS WHAT WE`LL DEPICT FOR TONIGHT. THE FRONT WILL MOVE INTO SOUTH FLORIDA ON MONDAY, BUT LIKELY STALL OVER THE EXTREME SOUTHERN PORTION OF THE AREA BY MONDAY NIGHT AS THE STRONG RIDGE HELPS TO PUT THE BRAKES ON ANY SOUTHWARD PROGRESS OF THE FRONT. ONLY SLIGHT COOLING BEHIND THE FRONT (NEAR 80 INSTEAD OF MID 80S PALM BEACHES AND LAKE AREA) WITH NE WINDS PROVIDING A SLIGHT CHANCE OF SHOWERS EASTERN METRO AREAS. FRONT WILL BE DIFFUSE ON TUESDAY BUT ENOUGH LINGERING MOISTURE TO KEEP IN A PESKY 20/30% CHANCE OF SHOWERS AREA-WIDE. ONLY A COUPLE OF DEGREES COOLER FOR HIGH TEMPERATURES, BUT STILL AROUND 80 TO THE LOWER 80S ON TUESDAY. BY WEDNESDAY, THINGS BEGIN TO CHANGE AS A STRONGER FRONT MOVES DOWN THE PENINSULA IN RESPONSE TO A DEEPENING EASTERN U.S. TROUGH. MODELS NOT SHOWING MUCH IN THE WAY OF LOW-LEVEL CONVERGENCE AHEAD OF THIS NEXT FRONT, THEREFORE SHOWER CHANCES WILL REMAIN ON THE LOW SIDE (LESS THAN 20%) DURING THE DAY ON WEDNESDAY AS HIGH TEMPS STILL MANAGE TO REACH THE MID 70S TO AROUND 80. LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)... THE FRONT WILL MOVE THROUGH SOUTH FLORIDA WEDNESDAY NIGHT, USHERING IN MUCH COOLER (BUT NOT UNSEASONABLY COLD) AIR. AIR MASS BEHIND THIS FRONT IS PLENTY COLD, BUT GLOBAL MODELS AGREE IN SHOWING THE ARCTIC HIGH PRESSURE CENTER BEHIND THE FRONT TO SLIDE MORE EAST THAN SOUTH, GIVING SOUTH FLORIDA MORE OF A GLANCING BLOW THAN A STRAIGHT SHOT OF COLD AIR. CONSENSUS OF MODEL SOLUTIONS (INCLUDING ENSEMBLES) SHOW LOW TEMPERATURES THURSDAY AND FRIDAY MORNINGS RANGING FROM THE MID 40S WEST OF LAKE OKEECHOBEE TO NEAR 60 EAST COAST, NOT TOO FAR FROM EARLY JANUARY NORMALS). THE SHALLOW NATURE OF THIS FRONT ALSO MEANS THAT INSTEAD OF THE TYPICAL CLEARING BEHIND STRONG FRONTS, WE WILL LIKELY SEE AN EXTENDED PERIOD OF CLOUDS AND SCATTERED SHOWERS, PARTICULARLY EASTERN METRO AREAS. THIS COULD LEAD TO LOWER MAX TEMPERATURES ON THURSDAY AND FRIDAY THAN WHAT IS CURRENTLY FORECAST. MODELS SHOW PLENTY OF MOISTURE HANGING AROUND THROUGH NEXT WEEKEND, SO IT LOOKS LIKE A RATHER GLOOMY SECOND HALF OF THE WEEK INTO NEXT WEEKEND FOR SOUTH FLORIDA. MARINE... AFTER SOME HIGHER WIND GUSTS TODAY, WINDS DECREASE TONIGHT WITH SUBSIDING SEAS. A BRIEF SURGE IN NORTHEAST WINDS BEHIND THE FRONT ON MONDAY AND MONDAY NIGHT, FOLLOWED BY LIGHT E-NE WINDS TUESDAY INTO WEDNESDAY. THE NEXT FRONT ON WEDNESDAY WILL BE FOLLOWED BY MUCH STRONGER NORTH WINDS, WITH WINDS NEAR 25 KT LIKELY WITH HIGHER GUSTS AND ROUGH SEAS LASTING THROUGH THURSDAY. CLIMATE... THIS MORNING`S LOW TEMPERATURES AT ALL FOUR MAIN CLIMATE SITES ARE ON PACE TO EITHER TIE OR BREAK HIGH MINIMUM RECORDS FOR THE DATE: MIA: AM LOW 76/RECORD 76 (1971) FLL: AM LOW 75/RECORD 74 (2007) PBI: AM LOW 76/RECORD 73 (2007) APF: AM LOW 70/RECORD 68 (1973) && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 70 80 70 80 / 10 20 20 20 FORT LAUDERDALE 72 81 72 80 / 10 20 20 10 MIAMI 72 82 71 81 / 10 20 20 10 NAPLES 68 80 65 80 / 10 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
233 PM EST SAT JAN 3 2015 .NEAR TERM...TONIGHT... PARTIAL SUNSHINE HELPING TO PUSH AFTERNOON TEMPERATURES UP CLOSE TO RECORD VALUES IN SOME AREAS...NEW RECORD HIGH SET AT JAX. MODEL GUIDANCE SUGGESTS LOW CLOUDS WILL DEVELOP OVER THE AREA AGAIN LATE TONIGHT. THIS...ALONG WITH S TO SE FLOW WILL KEEP LOW TEMPS UP TONIGHT IN LOW/MID 60S. MOS GUIDANCE HITTING FOG HARD TONIGHT...HOWEVER...THINK THIS WILL BE LIMITED BY 20KT WINDS FORECAST ABOVE THE GROUND...WITH 4-6KT SFC WINDS...SO FOCUSING MORE ON A LOW CLOUD DECK LATE TONIGHT THAN WIDESPREAD FOG... THOUGH SOME PATCHY FOG COULD OCCUR IN SHELTERED AREAS. RADAR CURRENTLY SHOWING A FEW SHOWERS NW FL ALONG W COAST SEABREEZE... WHICH WILL WORK NORTHEASTWARD. NAM/HRRR SUGGEST POTENTIAL FOR SOME SHOWERS TO DEVELOP LATE THIS AFTERNOON INTO EARLY EVENING OVER EAST-CENTRAL PENINSULA WHERE THEY HAVE EAST AND WEST COAST SEA BREEZES CONVERGE. GFS DOES NOT SHOW ANY PRECIP. SOME QUESTION OF COVERAGE GIVEN DRY AIR/WARMER TEMPS ALOFT. GIVEN CURRENT SATLT/RADAR TRENDS... WILL AT LEAST HAVE 20 POPS WITH SEA BREEZES THRU MID EVENING. SHORT TERM...SUNDAY...COLD FRONT WILL BE APPROACHING FROM THE WEST EARLY SUNDAY AFTERNOON WITH A BAND OF SHOWERS AND WIDELY SCATTERED THUNDERSTORMS PUSHING INTO SE GA AND THE SUWANNEE VALLY. MODELS IN BETTER AGREEMENT WITH THE TIMING SHOWING FRONT BISECTING THE AREA BY 00Z AND EXITING NE FL AROUND 06Z MONDAY. MODEL SOUNDINGS SHOW A UNIDIRECTIONAL SW WIND PROFILE WITH DEEP LAYER SPEED SHEAR. THIS ALONG WITH DRY MID LEVELS WOULD SUPPORT STRONG GUSTY WINDS IN ANY STRONG THUNDERSTORMS THAT FORM. FORECAST CAPES IN 500-1000 J/KG COULD BE ENOUGH WITH STRONG SHEAR TO PRODUCE ISOLATED STRONG TO MARGINALLY SEVERE STORMS OVER MAINLY SE GA AS SHORT WAVE GOES BY TO THE NORTH. TIMING OF STORMS SHOULD BE DURING THE AFTERNOON AND EARLY EVENING HOURS. MONDAY AND TUESDAY...RAIN WILL BE ENDING OVER NE FL EARLY MONDAY MORNING AS DRIER AIR MOVES IN BEHIND COLD FRONT. WINDS WILL BECOME ONSHORE MONDAY NIGHT AND TUESDAY AS MODELS SHOW WEAK INVERTED TROUGH FORMING OVER THE ATLANTIC WATERS. THIS MAY PRODUCE ISOLATED COASTAL SHOWERS NEAR THE COAST WITH DRY CONDITIONS INLAND. TEMPERATURES WILL BE SEASONABLE. .LONG TERM...WEDNESDAY THROUGH SATURDAY...MODELS CONTINUE TO SHOW A STRONG ARCTIC OUTBREAK NEXT WEEK AS UPPER AIR PATTERN AMPLIFIES. ECMWF MODEL SHOWS A 1060 MB SURFACE HIGH CENTERED OVER THE NORTHERN PLAINS ON WEDNESDAY BUILDING SE. THIS HIGH CENTER WILL MOVE INTO THE SOUTHERN PLAINS THURSDAY AND THE SOUTHEAST U.S. THURSDAY NIGHT AND FRIDAY. MAX TEMPERATURES WILL FALL FROM NEAR AVERAGE LEVELS ON WEDNESDAY TO WELL BELOW NORMAL THURSDAY(40S) AND FRIDAY(50S) BEFORE REBOUNDING BACK TO NEAR NORMAL SATURDAY. MOS GUIDANCE SHOWS HARD FREEZES OVER INLAND SE GA AND THE SUWANNEE VALLEY OF NE FL WEDNESDAY NIGHT AND THURSDAY NIGHT. PRESSURE GRADIENT WILL REMAIN TIGHT THROUGH THURSDAY WITH STRONG HIGH BUILDING INTO THE AREA. THIS WILL KEEP WINDS ELEVATED WITH LOW WIND CHILLS IN THE TEENS AND 20S WEDNESDAY NIGHT. THURSDAY NIGHT WILL LIKELY BE THE COLDEST NIGHT AS WINDS DECREASE. AN ONSHORE FLOW WILL INCREASE TEMPERATURES AND MOISTURE NEXT WEEKEND. && .AVIATION...CIGS HAVE BEEN SLOW TO GET UP INTO VFR RANGE TODAY...BUT MOST CIGS HAVE REACHED AT OR ABOVE BKN030 WITH LATEST OBSERVATIONS. MODEL GUIDANCE SUGGESTS VFR CONDITIONS THRU SUNSET...THEN CIGS LOWERING TO IFR LATER TONIGHT AND CONTINUING THROUGH SUN MORNING. FOLLOWED THIS EVOLUTION IN LATEST TAFS. && .MARINE...MODEL GUIDANCE SUGGESTS AN INCREASE IN SOUTHERLY FLOW LATER TONIGHT... WITH 15-20 KTS LIKELY IN OFFSHORE COMPONENT...WILL HAVE SCEC THERE. UNCERTAIN ABOUT THREAT OF SEA FOG...WHICH HRRR IS AGAIN FORECASTING. WE DO HAVE MID/UPR 60S DEW POINTS OVER LAND...BUT EXPECTED EAST COAST SEA BREEZE LIKELY TO KEEP IT OVER LAND THRU SUNSET. LAND BREEZE THIS EVENING MAY ADVECT THE HIGHER DEW POINT AIR OVER THE COASTAL WATERS...SUPPORTING SEA FOG FORMATION OVER COOLER SHELF WATERS. UNCERTAINTY AS TO HOW WIDESPREAD OR DENSE GIVEN 10-15KT SURFACE WINDS...BUT WILL INCLUDE AREAS OF FOG TONIGHT FOR NEARSHORE COMPONENT...MAINLY EAST OF DUVAL COUNTY FL NORTHWARD. && .PRELIMINARY POINT TEMPS/POPS... AMG 62 76 46 57 / 20 80 70 0 SSI 62 72 49 57 / 20 60 60 0 JAX 64 79 53 60 / 20 50 60 0 SGJ 65 77 56 59 / 20 30 50 20 GNV 63 77 56 62 / 10 50 60 10 OCF 65 79 58 64 / 10 30 50 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && $$ WOLF/ZIBURA/
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
308 PM EST SAT JAN 3 2015 ...SEVERE STORMS POSSIBLE NW GEORGIA AFTER MIDNIGHT... ...HEAVY RAIN LIKELY MUCH OF NORTH GEORGIA TONIGHT AND SUNDAY MORNING... .SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... ONLY MINOR REFINEMENTS MADE TO GRIDS SINCE LAST DISCUSSION /SEE BELOW/ BASED ON OBSERVED TRENDS AND LATEST HRRR GUIDANCE. APPEARS LINE OF CONVECTION STILL ON TARGET TO MOVE INTO NW GEORGIA AFTER 06Z THEN PUSH INTO ATL METRO AROUND 11-12Z WHILE ON A WEAKENING TREND. WIDESPREAD DRIZZLE AND FOG WITH SCT -SHRA TO CONTINUE UNTIL THEN. PRECIP SHOULD END QUICKLY BEHIND MAIN PREFROTNAL SQUALL LINE. HAVE MANUALLY DRAWN POPS AS LACK OF GOOD HOURLY MODEL GUIDANCE EXISTS TODAY. COULD SEE VERY ISOLD CONVECTION BEHIND THIS LINE SUN AFTERNOON BUT SUBJECTIVE EXPERIENCE IN THIS PATTERN IS COVERAGE AND INTENSITY WILL BE MUCH LESS THAN INDICATED BY MODEL GUIDANCE. WINDS SHOULD BE STRONG BUT REMAIN BELOW ADVISORY CRITERIA SUN AND SUN EVENING. SNELSON .LONG TERM /MONDAY THROUGH SATURDAY/... VERY FEW CHANGES NEEDED FOR THE LONG TERM PORTION OF THE FORECAST. HIGH PRESSURE WILL MOVE OFFSHORE THE MID ATLANTIC COAST ON MONDAY IN ADVANCE OF A COLD FRONT ON TUESDAY. TUESDAYS FRONT IS EXPECTED TO BE DRY. A STRONG AREA OF HIGH PRESSURE WILL BUILD BEHIND THE FRONT WEDNESDAY INTO THURSDAY...BRINGING A MUCH COLDER AND DRIER AIRMASS TO THE SOUTHEAST STATES. THERE WERE SOME EARLIER DIFFERENCES BETWEEN THE LONGER TERM MODELS WITH FORECAST MINS AND MAX TEMPS WEDNESDAY INTO THURSDAY...THE GFS HAS TRENDED A LITTLE COLDER AND CLOSER TO THE ECMWF VALUES. IN ADDITION TO THE COLDER TEMPERATURES...BREEZY OR EVEN WINDY CONDITIONS ARE EXPECTED WEDNESDAY INTO EARLY THURSDAY. VALUES COULD APPROACH WIND ADVISORY CRITERIA...AND BRING LOW WIND CHILLS. TEMPERATURES ARE EXPECTED TO MODERATE FAIRLY QUICKLY FRIDAY INTO THE WEEKEND. NLISTEMAA && .HYDROLOGY... STILL ON TRACK TO SEE 1 TO 2 INCHES WITH AMOUNTS OVER 1.5 INCHES CONFINED TO NE GA. BASED ON THIS EXPECTATION AND FFG HAVE DECIDED NOT TO ISSUE ANY KIND OF FLOOD WATCH. WILL CONTINUE TO MONITOR THIS EVENING. SNELSON && .PREV DISCUSSION... /ISSUED 149 PM EST SAT JAN 3 2015/ UPDATE... NEAR TERM FCST APPEARS ON TRACK. MAIN CONCERN IS POTENTIAL FOR SVR STORMS AND HVY RAIN. 12Z SYNOPTIC MODELS AND HIRES GUIDANCE INDICATING LINE OF CONVECTION SHOULD MOVE INTO NW CORNER AROUND OR AFTER 06Z. NAM AND GFS 0-1KM BULK SHEAR /35-45KTS/ AND MLCAPE /100-250 J/KG/ FAVORABLE FOR QLCS STORMS WITH ISOLD WIND DMG AND EVEN BRIEF TORNADO POSSIBLE IN THE NW 1/3RD OF GA BETWEEN 06Z AND 12Z...MAINLY NORTH OF I-85. LATEST QPF GUIDANCE INDICATING 1 TO 2 INCHES THRU 00Z MON WITH ONLY NE GA AREA EXPECTING AMOUNTS OF 1.5 INCHES. 3HR FFG IS QUITE LOW /2-2.5 INCHES/ IN NORTH GA DUE TO ANTECEDENT RAINFALL THE LAST 36 HRS. WILL BE COLLABORATING AND LOOKING AT A LITTLE MORE DATA BEFORE DECIDING BUT FOR NOW HOLDING OFF ON WATCH. SNELSON && .AVIATION... 18Z UPDATE... LIFR/IFR CONDITIONS WILL PERSIST THRU ABOUT 14Z SUN AFTER LINE OF HVY SHRA MOVES THRU. VFR CONDITIONS LIKELY AFTER 17Z. EAST COMPONENT SFC WINDS WILL ALSO VEER TO SW AFTER LINE OF SHRA MOVES THRU. COULD SEE ISOLD TSRA BUT WITH LOW INSTABILITY...LIKELIHOOD TOO SMALL TO MENTION IN FCST. //ATL CONFIDENCE...18Z UPDATE... HIGH CONFIDENCE ON ALL ELEMENTS. SNELSON && .PRELIMINARY POINT TEMPS/POPS... ATHENS 53 65 35 54 / 40 100 10 0 ATLANTA 57 62 34 50 / 60 100 10 0 BLAIRSVILLE 52 58 29 46 / 80 100 10 5 CARTERSVILLE 55 61 31 46 / 90 100 10 0 COLUMBUS 63 67 36 53 / 40 100 10 0 GAINESVILLE 49 61 33 50 / 50 100 10 0 MACON 63 69 37 55 / 30 100 10 5 ROME 55 60 30 45 / 100 100 5 5 PEACHTREE CITY 59 63 34 51 / 60 100 10 0 VIDALIA 63 75 42 58 / 30 80 70 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...SNELSON LONG TERM....NLISTEMAA AVIATION...SNELSON
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1055 AM EST SAT JAN 3 2015 .SYNOPSIS... WEAK HIGH PRESSURE OVER THE AREA WILL RETREAT TONIGHT AS A WARM FRONT LIFTS NORTH. A COLD FRONT WILL PUSH THROUGH LATE SUNDAY FOLLOWED BY DRY HIGH PRESSURE. A SECONDARY COLD FRONT WILL DROP THROUGH WEDNESDAY EVENING WITH COLDER HIGH PRESSURE BUILDING IN FOR THURSDAY INTO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... LATE THIS MORNING...THE FORECAST FOR TODAY IS CERTAINLY COMPLEX WITH LOTS OF SUBTLETIES THAT WILL IMPACT THE SENSIBLE ELEMENTS. THE CURRENT SET UP FEATURES SOUTHWEST FLOW ALOFT AS THE REGION IS PLACED BETWEEN THE UPPER LOW ENTERING THE SOUTHERN PLAINS AND THE RIDGE IN THE VICINITY OF THE BAHAMAS. THERE ARE REALLY NO INTERESTING FEATURES EMBEDDED WITHIN THE SOUTHWEST FLOW ALOFT...AND THE ENVIRONMENT IS LARGELY VOID OF ANY DEEP LAYER FORCING. AT THE SURFACE...THE COLD AIR DAMMING REGIME IS LIKELY AT ITS PEAK OF MATURITY WITH A WELL DEVELOPED INVERTED RIDGE IN THE LEE OF THE APPALACHIANS AS NOTED IN SURFACE ANALYSIS. HOWEVER...THE CAD IS RELATIVELY WEAK AS NOTED IN THE 12Z KCHS SOUNDING WITH A VERY SHALLOW LAYER UP TO ONLY ABOUT 2 KFT. FURTHERMORE...ACROSS THE FORECAST AREA...THERE IS NOT A TREMENDOUS TEMPERATURE GRADIENT AS CURRENT READINGS HAVE ALREADY REACHED TO NEAR 60 AT THE COAST AND RISING INTO THE UPPER 50S JUST INLAND. THE SOUTHERN EXTENT OF THE HEART OF THE WEDGE IS LIKELY SOMEWHERE AROUND THE SAVANNAH RIVER AS OBSERVATION SITES SOUTH OF THE RIVER ARE ALREADY REPORTING FLOW THAT HAS AN INCREASING EASTERLY COMPONENT. ALL THIS IS TO SAY THAT THE WEDGE IS NOT FIRMLY ENTRENCHED AND SHOULD BE REASONABLY EASY TO SCOUR OUT THROUGH THE AFTERNOON. WE HAVE PROGGED THE FLOW VEERING TO MORE EASTERLY AND SOUTHEASTERLY IN THE 18Z-21Z TIME PERIOD BASED ON THE HRRR AND RAP. THE TRANSITION WILL TAKE LONGEST ACROSS THE TRI-COUNTY WHERE ONGOING PRECIPITATION WILL LEAD TO SOME LOCAL DIABATIC ENHANCEMENT AND IT MAY HANG ON IN THIS AREA A BIT LONGER. THE ONGOING RAINFALL IS MAINLY AFFECTING THE SOUTH CAROLINA ZONES AS IT FEEDS IN OFF THE ATLANTIC WITHIN A SHALLOW ISENTROPIC LIFT REGIME. MODEL TIME HEIGHTS SHOW THAT THE ATMOSPHERE ABOVE 5 KFT IS QUITE DRY SO WE ARE PRIMARILY DEALING WITH SHALLOW/WARM PRODUCTION PROCESSES. POPS HAVE BEEN INCREASED TO LIKELY THROUGH THE EARLY AFTERNOON FOR THE EASTERN HALF OF THE AREA WITH SLIGHT CHANCES FURTHER WEST INCLUDING SAVANNAH. BASED ON UPSTREAM CLOUD COVER...WE MAY EVEN SEE SOME BREAKS OF SUN...ESPECIALLY FOR SOUTHEAST GEORGIA. GIVEN THAT TEMPERATURES ARE ALREADY SO WARM...I HAVE RAISED HIGHS FOR TODAY 3-5 DEGREES. THE SAVANNAH AREA COULD EVEN REACH THE MID 70S BY THE LATE AFTERNOON...DEPENDING ON HOW MUCH SUN ACTUALLY BREAKS THROUGH. OVERNIGHT...THE FOCUS SHIFTS TO A POTENTIAL FOR FOG AND PERHAPS PERIODS OF DENSE FOG IN SOME LOCATIONS ALONG THE COAST AND INLAND SE SOUTH CAROLINA. THERE IS A 30 KT LOW LEVEL JET WHICH STRENGTHENS TO 40 KT LATE BUT SOME CLASSIC BUILD- DOWN STRATUS SIGNATURES ARE SHOWN ON FORECAST SOUNDINGS IN THESE AREAS. AREAS OF FOG IN THE FORECAST TONIGHT WITH PATCHY FOG INLAND SE GEORGIA. ANOTHER FOG ISSUE MAY BE SEA FOG/STRATUS ADVECTING ONSHORE INTO THE COAST COMPLICATING THE ALREADY COMPLEX LOW LEVEL THERMAL ENVIRONMENT AND FORECAST FOR FOG IN SPACE AND TIME. WE CONTINUED TO MENTION A DENSE FOG POTENTIAL TONIGHT IN THE HAZARDOUS WEATHER OUTLOOK. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... A POTENT UPPER SHORTWAVE WILL SHIFT EAST INTO THE CENTRAL APPALACHIANS ON SUNDAY...DRIVING A COLD FRONT INTO THE EASTERN UNITED STATES LATE SUNDAY AFTERNOON. THE BRUNT OF THE UPPER VORT ENERGY WILL REMAIN WELL NORTH OF THE FORECAST AREA. HOWEVER...A ROBUST 45-50 KT 850 MB JET WILL DEVELOP ACROSS THE AREA SUNDAY AFTERNOON...ADVECTING A WARM AND MOIST AIRMASS INTO THE AREA. SFC DEWPOINTS ARE PROGGED TO RISE INTO THE UPPER 60S WHILE TEMPS WILL REACH THE MID TO UPPER 70S. ATOP THE TROPOSPHERE A 180 KT JET STREAK WILL PUSH INTO THE MID-ATLANTIC REGION DURING THE AFTERNOON... SPREADING EXTENSIVE UPPER DIVERGENCE INTO THE SOUTHEAST STATES LATE. A WEAK VORT WILL LIFT UP THE COAST SUNDAY MORNING...POTENTIALLY SPURRING SCATTERED RAIN SHOWERS. HOWEVER...FOR THE MIDDLE OF THE DAY THERE WILL NOT BE MUCH FORCING FOR PRECIPITATION SO WE ONLY SHOW SLIGHT CHANCE POPS LATE MORNING AND EARLY AFTERNOON. THERE IS FAIRLY GOOD MODEL AGREEMENT THAT THE FRONTAL BAND WILL PUSH INTO OUR WESTERN ZONES MID TO LATE AFTERNOON AND SHIFT OFF THE COAST BEFORE MIDNIGHT SUNDAY NIGHT. MOISTURE AND LIFT WILL SUPPORT LIKELY TO CATEGORICAL POPS DURING THIS PERIOD. THE SEVERE WEATHER POTENTIAL LOOKS MARGINAL AT BEST. AS WE OFTEN SEE IN COLD-SEASON SYNOPTIC SCALE SYSTEMS...SHEAR PARAMETERS ARE PRETTY STRONG BUT THE ALL-IMPORTANT SURFACE-BASED INSTABILITY WILL BE VERY LIMITED. BY THE TIME THE FRONT MAKES ITS WAY INTO THE AREA...CAPE VALUES WILL BE LESS THAN 500 J/KG AND LAPSE RATES WILL BE LESS THAN 6C/KM. EXTENSIVE CLOUDINESS WILL PRECEDE THE FRONT...LIMITING THE CHANCE THAT POCKETS OF ENHANCED SURFACE-BASED INSTABILITY WILL DEVELOP. GIVEN THE STRONG WIND FIELDS...AN ISOLATED DAMAGING WIND GUST CANNOT BE RULED OUT BUT AT THIS TIME WE ARE NOT ANTICIPATING MUCH SEVERE WEATHER. THE COLD FRONT WILL BE OFFSHORE BY MIDNIGHT...WITH WEAK HIGH PRESSURE BUILDING IN BEHIND. DESPITE THE WEAK COLD ADVECTION... WESTERLY FLOW IN THE LOWER LEVELS WILL SUPPORT DOWNSLOPE COMPRESSION AND HIGH TEMPS AROUND 60F MONDAY AND TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... A POWERFUL UPPER TROUGH WILL DIG ACROSS THE CENTRAL AND EASTERN UNITED STATES MID TO LATE WEEK...EVENTUALLY ALLOWING A VERY COLD AIRMASS FROM CANADA TO DROP INTO THE SOUTHEAST UNITED STATES. AN INITIAL WEAK COLD FRONT WILL DROP THROUGH LATE TUESDAY NIGHT... KEEPING WEDNESDAY HIGHS IN THE MID 50S. A MUCH STRONGER COLD FRONT WILL MOVE THROUGH WEDNESDAY EVENING...WITH STRONG COLD ADVECTION DROPPING THURSDAY MORNING TEMPS INTO THE MIDDLE 20S. AN INTENSELY DRY CANADIAN AIRMASS WILL SHIFT OVER THE AREA THURSDAY WITH DEWPOINTS DROPPING INTO THE SINGLE DIGITS. GIVEN GROWING MODEL CONSENSUS WE FURTHER DROPPED THURSDAY HIGH TEMPS...NOW SHOWING HIGHS AROUND 40 NORTH TO MIDDLE 40S SOUTH. INTERESTINGLY...THE ECMWF REMAINS THE COLDEST MODEL...CONTINUING TO SHOW HIGH TEMPS ONLY IN THE MIDDLE 30S. THE HIGH WILL SETTLE OVER THE AREA THURSDAY NIGHT WITH CLEAR SKIES AND DIMINISHING WINDS SUPPORTING A HARD FREEZE. WE DROPPED LOWS INTO THE MID 20S INLAND FROM THE COAST...BUT THERE IS A POTENTIAL FOR LOWS IN THE UPPER TEENS IF THE ECMWF VERIFIES. COLD WEATHER PERSISTS FRIDAY INTO SATURDAY THOUGH A SLIGHT WARMING TREND ENSUES AS THE HIGH SHIFTS NORTHEAST. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... KCHS...CIGS WILL REMAIN IFR THROUGH THE REST OF THE MORNING AS SHOWERS STREAM IN FROM THE ATLANTIC. CEILINGS SHOULD THEN LIFT TO MVFR THIS AFTERNOON BEFORE BUILDING DOWN AGAIN THIS EVENING AND ESPECIALLY OVERNIGHT. THERE MAY BE A PERIOD OF FOG THIS EVENING IF THE WEDGE IS SLOW TO SCOUR TODAY OR SEA FOG/STRATUS ADVECT ONSHORE AT ANY POINT LATER TODAY OR TONIGHT. RAIN CHANCES LOOK BEST THROUGH MID AFTERNOON THEN MAINLY VCSH OR PATCHY DRIZZLE TONIGHT. KSAV...IFR CIGS WILL LIKELY PERSIST THROUGH THE MORNING AS WARMER AIR STREAMS OVER THE WEDGE AIR MASS AT THE SURFACE. A WARM FRONT WILL STRUGGLE THROUGH THE TERMINAL LATER TODAY WITH SURFACE FLOW TURNING MORE SE AND EVENTUALLY S LATE. LOW CIGS COULD EASILY HANG IN ALL DAY BUT CONFIDENCE HIGHEST TONIGHT FOR IFR/LIFR CIGS. RAIN CHANCES/TIMING NOT HIGH ENOUGH TO PREVAIL ANY SHOWERS. BOTH TERMINALS COULD EXPERIENCE LOW END LLWS CONDITIONS LATE TONIGHT OR TONIGHT. EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CEILINGS ARE LIKELY TO PERSIST THROUGH SUNDAY EVENING. SCATTERED SHOWERS AND ISOLATED TSTMS EXPECTED LATE SUNDAY AFTERNOON INTO THE EVENING. VFR CONDITIONS RETURN LATE SUNDAY NIGHT. && .MARINE... THE PRES GRADIENT HAS BEEN PINCHING OVERNIGHT ALONG THE COAST NORTH OF THE SAVANNAH RIVER ENTRANCE CLOSE TO 15 KT WITH HIGHER GUSTS AT TIMES ALONG THE CHARLESTON COUNTY COAST. THIS GRADIENT IS FORECAST TO WEAKEN BY MID MORNING. LIGHT WINDS TRYING TO VEER THIS AFTERNOON BUT IT WILL BE A DIFFICULT TASK AS THE MARINE LAYER IS STABLE AND COOL. LATEST H3R MODEL SHOWS A LIGHT AND VARIABLE WIND REGIME THIS AFTERNOON EVENTUALLY TURNING SE AROUND DUSK ACROSS THE NEAR SHORE WATERS. THE FLOW WILL VEER SOUTHERLY LATER TONIGHT WITH SPEEDS INCREASING GRADUALLY. SEAS WILL BUILD TO 4-6 FT WELL OFF THE CHARLESTON COUNTY COAST LATE AND OVER THE 20-60 NM GEORGIA WATERS SOMETIME AFTER MIDNIGHT. THE MAIN PROBLEM TODAY AND TONIGHT SHOULD BE THE DEVELOPMENT OF SEA FOG AS ELEVATED MOIST DEW POINTS IN THE 60S STREAM OVER THE MARINE LAYER. FOG IS IN THE FORECAST AND THERE ARE GOOD CHANCES FOR MARINE FOG ADVISORIES STARTING LATER TODAY INTO TONIGHT. THE ONSHORE TRAJECTORIES SUGGEST SEA FOG/STRATUS WILL ADVECT INTO SOME OF OUR COASTAL AREAS INCLUDING THE CHARLESTON HARBOR. THE WARM ADVECTION REGIME CONTINUES SUNDAY WITH STRONG SOUTHERLY WINDS MOVING ACROSS COOL COASTAL WATERS. SMALL CRAFT CONDITIONS... MAINLY IN 6 FT SEAS...EXPECTED OVER THE GA OFFSHORE AND CHARLESTON SC NEARSHORE WATERS SUNDAY AND SUNDAY NIGHT. SEA FOG WILL LIKELY REMAIN A CONCERN FOR ALL NEARSHORE AREAS INCLUDING CHARLESTON HARBOR DUE TO MID TO UPPER 60S DEWPOINTS RESIDING OVER 50S WATER TEMPS. ANY SEA FOG WILL BE CLEARED OUT SUNDAY NIGHT BEHIND THE COLD FRONT AS DRIER AIR SHIFTS IN. COLD ADVECTION ON MONDAY WILL MAINTAIN SMALL CRAFT CONDITIONS OVER THE OFFSHORE GA WATERS BEFORE CONDITIONS RELAX. MARGINAL SMALL CRAFT CONDITIONS POSSIBLE WEDNESDAY BEHIND A WEAK COLD FRONT. HOWEVER THE MAIN CONCERN WILL BE POSSIBLE GALES WEDNESDAY NIGHT AND THURSDAY BEHIND A POWERFUL COLD FRONT. GEOSTROPHIC WINDS OF 40-45 KT AND STRONG COLD ADVECTION COULD ALLOW FOR FREQUENT 35 KT GUSTS...AT A MINIMUM OVER THE OFFSHORE GA WATERS. WE WILL ADD MENTION TO THE HAZARDOUS WEATHER OUTLOOK. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST MONDAY FOR AMZ374. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 5 AM EST MONDAY FOR AMZ350. && $$ NEAR TERM...BSH SHORT TERM...JRL LONG TERM...JRL AVIATION... MARINE...JRL
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
118 PM EST SAT JAN 3 2015 .SYNOPSIS... ISSUED AT 104 PM EST SAT JAN 3 2015 LOW PRESSURE WILL MOVE OUT OF THE SOUTHWEST TOWARDS THE SOUTHERN GREAT LAKES TONIGHT. RAIN WILL PERSIST ACROSS THE AREA THROUGH THE AFTERNOON. HIGHS TODAY WILL RANGE FROM THE MIDDLE 30S NORTHWEST TO NEAR 50 IN THE SOUTHEAST. && .UPDATE... ISSUED AT 102 PM EST SAT JAN 3 2015 HAVE ALLOWED MOST OF THE ADVISORY TO EXPIRE WITH TEMPERATURES AND ROAD CONDITIONS SUFFICIENTLY IMPROVED TO ALLOW FOR BETTER TRAVEL ACROSS THE AREA. SECONDARY ROADS WILL STILL REMAIN SLICK IN SOME AREAS THROUGH THE AFTERNOON. ACROSS FAR NE INDIANA...FAR NW OHIO AND INTO HILLSDALE COUNTY TEMPS WERE LINGERING AROUND 32 DEGREES YET WITH CALL AROUND TO DISPATCHES STILL SHOWING ISSUES. RATHER THAN HAVE TO ADDRESS AGAIN AT 2 PM HAVE OPTED TO EXTEND TO 4 PM AND WILL ADDRESS WITH AFTERNOON PACKAGE WHEN IT SHOULD BE ABLE TO EXPIRE. NO OTHER MAJOR CHANGES TO GRIDS AT THIS TIME. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 403 AM EST SAT JAN 3 2015 IMPRESSIVE SRN STREAM SW TROUGH NOTED IN VAPOR THIS MORNING AND BEGINNING TO LIFT OUT OF NM. THIS SYS WILL PHASE QUICKLY TONIGHT W/NRN STREAM SW AMPLIFYING SEWD OUT OF THE NRN ROCKIES RESULTING IN A RAPID NEWD EJECTION INTO SE CANADA BU SUN MORNING. BROAD LOW-MID LVL MSTR SURGE JUST NOW GETTING UP INTO THE AREA W/MORE VIGOROUS PRECIP DVLPMNT NOTED IN COMPOSITE RADAR IMAGERY BACK ACRS CNTRL IL INTO WRN IN AND POSES AN ICING PROB EARLY ON W/CURRENT SFC TEMPS IN THE UPR 20S. HWVR LL WAA QUITE INTENSE AS NOTED OVR SRN IL/IN AND XPCD TO PROGRESS NWD THROUGH THIS MORNING. GIVEN GOOD 00Z CONSENSUS W/CORRESPONDING RUC NOD TO SFC TEMPS CUT BACK TIMING OF ADVISORY ACRS FAR SRN TIER OF COUNTIES YET WILL HOLD W/REMAINDER OF ADVISORY SEGMENTS PER LTL XPCD SFC BASED WARMING WILL OCCUR UNTIL MID-LT MORNING TIED TO DEEPER ERLY FLW TRAJECTORIES AND MUCH LWR THETA-E AIR ORIGINATING FM OLD POLAR RIDGE. REGARDLESS LL WAA WILL OVERWHELM SHALLOW SFC BASED COLD LYR BY LT MORNING/ERLY AFTN S-N W/A DECENT RAIN EVENT XPCD ESP SE HALF. MID LVL DRY SLOT WILL OVERSPREAD AREA LT THIS AFTN WEST AND OVERNIGHT EAST ALTHOUGH TEMPS WILL FAIRLY MILD. EXCEPTION WILL BE FAR WEST WHERE INTENSE LL CAA WING WILL BEGIN TO WRAP SEWD BEHIND DEPARTING SFC LOW. LEFT OVER DEFORMATION ZONE AND RAPID INFLUX OF COLD AIR WILL LEAD TO A RAPID CHG OVR TO ACCUMULATING SNOW FAR NW AND EXPANDING SEWD DURING THE DAY AS MSTR FLUX OFF LK MI TAKES OFF. SHLD SEE A PD OF ROBUST LK ENHANCEMENT THROUGHOUT THE NW HALF SUN AFTN W/AT LEAST AN INCH OR TWO OF SNOWFALL XPCD. && .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 403 AM EST SAT JAN 3 2015 BITTERLY COLD CONDITIONS CAN BE EXPECTED FOR MUCH OF THE LONG TERM FORECAST DURING THE UPCOMING WEEK. STRONG COLD AIR ADVECTION WILL BE OCCURRING AT THE START OF THIS PERIOD SUNDAY NIGHT. A STRONG UPPER LEVEL DISTURBANCE WILL SUPPORT THE DEVELOPMENT OF A CLIPPER TYPE SYSTEM THAT SHOULD RACE ACROSS THE AREA MONDAY NIGHT INTO EARLY TUESDAY. FAVORED THE ECMWF RUN TO RUN CONSISTENCY AND HANDLING OF THIS SYSTEM. TEMPERATURES WILL BE COLD ENOUGH FOR ALL SNOW...WITH 3 TO 6 INCHES EXPECTED BY MID DAY TUESDAY. GIVEN FRESH SNOW COVER AND 850 MB TEMPERATURES DROPPING WELL BELOW -20...OVERNIGHT LOWS SHOULD BE ABLE TO FALL BELOW ZERO. LOWERED TEMPS TUESDAY NIGHT THROUGH THURSDAY NIGHT IN THIS REGARD. WIND CHILLS WILL DIP TO -20 AT TIMES DURING THE MIDDLE OF THE WEEK...WITH ADVISORY CONDITIONS LIKELY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 102 PM EST SAT JAN 3 2015 FREEZING PRECIP HAS ENDED AT BOTH SITES WITH PERIODS OF RAIN EXPECTED THROUGH THE AFTERNOON. RAIN MAY END AT KSBN BUT SOME DRIZZLE WILL REMAIN POSSIBLE. BIGGEST CHANGES TO TAFS WERE WITH KFWA WHERE A LLWS GROUP WAS INTRODUCED AS KIWX 88D VAD WINDS AND HI RES MODELS INDICATE A QUICK INCREASE IN LOW LEVEL WINDS IN RESPONSE TO DEEPENING LOW PRESSURE. ONCE THE LOW PASSES OVERHEAD...THE THREAT SHOULD DIMINISH. LATER THIS EVENING AS THE STEADIER RAIN ENDS...THE WARM AIR ALOFT OVER THE COLD GROUND SHOULD ALLOW FOR A FAVORABLE SETUP FOR SOME FOG DEVELOPMENT FOR A PERIOD. HAVE ADDED THIS TO TAFS FOR OVERNIGHT. FOCUS WILL THEN SHIFT TO COLD FRONT SET TO MOVE THROUGH AROUND 9Z AT KSBN AND 11Z AT KFWA. LAKE ENHANCED SNOW SHOWERS WILL QUICKLY TAKE SHAPE ACROSS KSBN GIVEN THEM A CONTINUATION OF IFR/LIFR CONDITIONS. LITTLE IMPROVEMENT WILL OCCUR THROUGH 18Z WITH VSBYS BECOMING A GREATER CONCERNS POTENTIALLY AFTER 18Z AS A SECONDARY WAVE MOVES IN AND BRINGS A BURST OF ADDITIONAL SNOWFALL TO THE AREA (WHICH WILL ALSO IMPACT KFWA). FURTHER CHANGES WILL LIKELY OCCUR TO THE TAFS IN LATER FORECASTS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR INZ006- 007. MI...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ079>081. OH...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR OHZ001- 002. LM...GALE WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR LMZ043-046. && $$ UPDATE...FISHER SYNOPSIS...FISHER SHORT TERM...T LONG TERM...SKIPPER AVIATION...FISHER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1118 AM EST SAT JAN 3 2015 .SYNOPSIS... ISSUED AT 943 AM EST SAT JAN 3 2015 LOW PRESSURE WILL MOVE OUT OF THE SOUTHWEST TOWARDS THE SOUTHERN GREAT LAKES SATURDAY NIGHT. AREAS OF FREEZING RAIN AND SNOW WILL CHANGE TO ALL RAIN BY EARLY AFTERNOON AS TEMPERATURES WARM ABOVE FREEZING. HIGHS TODAY WILL RANGE FROM THE MIDDLE 30S NORTHWEST TO NEAR 50 IN THE SOUTHEAST. && .UPDATE... ISSUED AT 1112 AM EST SAT JAN 3 2015 WHILE ICING HAS CALMED DOWN SIGNIFICANTLY BETWEEN ROUTE 24 AND 6... TEMPERATURES IN MANY AREAS WERE STILL LINGERING BETWEEN 32 AND 33...MAKING FOR A SLOW MELT OFF. THE COLD RAIN FALLING ON ICY SURFACES WAS STILL CAUSING SLIDE OFFS IN SEVERAL COUNTIES ALTHOUGH CONDITIONS ARE SLOWLY IMPROVING. DECIDED BEST OPTION AT THIS POINT WAS TO EXTEND THE HEADLINES A FEW HOURS. PULASKI AND FULTON COUNTY REPORTED NO ISSUES SO ALLOWED THEM TO EXPIRE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 403 AM EST SAT JAN 3 2015 IMPRESSIVE SRN STREAM SW TROUGH NOTED IN VAPOR THIS MORNING AND BEGINNING TO LIFT OUT OF NM. THIS SYS WILL PHASE QUICKLY TONIGHT W/NRN STREAM SW AMPLIFYING SEWD OUT OF THE NRN ROCKIES RESULTING IN A RAPID NEWD EJECTION INTO SE CANADA BU SUN MORNING. BROAD LOW-MID LVL MSTR SURGE JUST NOW GETTING UP INTO THE AREA W/MORE VIGOROUS PRECIP DVLPMNT NOTED IN COMPOSITE RADAR IMAGERY BACK ACRS CNTRL IL INTO WRN IN AND POSES AN ICING PROB EARLY ON W/CURRENT SFC TEMPS IN THE UPR 20S. HWVR LL WAA QUITE INTENSE AS NOTED OVR SRN IL/IN AND XPCD TO PROGRESS NWD THROUGH THIS MORNING. GIVEN GOOD 00Z CONSENSUS W/CORRESPONDING RUC NOD TO SFC TEMPS CUT BACK TIMING OF ADVISORY ACRS FAR SRN TIER OF COUNTIES YET WILL HOLD W/REMAINDER OF ADVISORY SEGMENTS PER LTL XPCD SFC BASED WARMING WILL OCCUR UNTIL MID-LT MORNING TIED TO DEEPER ERLY FLW TRAJECTORIES AND MUCH LWR THETA-E AIR ORIGINATING FM OLD POLAR RIDGE. REGARDLESS LL WAA WILL OVERWHELM SHALLOW SFC BASED COLD LYR BY LT MORNING/ERLY AFTN S-N W/A DECENT RAIN EVENT XPCD ESP SE HALF. MID LVL DRY SLOT WILL OVERSPREAD AREA LT THIS AFTN WEST AND OVERNIGHT EAST ALTHOUGH TEMPS WILL FAIRLY MILD. EXCEPTION WILL BE FAR WEST WHERE INTENSE LL CAA WING WILL BEGIN TO WRAP SEWD BEHIND DEPARTING SFC LOW. LEFT OVER DEFORMATION ZONE AND RAPID INFLUX OF COLD AIR WILL LEAD TO A RAPID CHG OVR TO ACCUMULATING SNOW FAR NW AND EXPANDING SEWD DURING THE DAY AS MSTR FLUX OFF LK MI TAKES OFF. SHLD SEE A PD OF ROBUST LK ENHANCEMENT THROUGHOUT THE NW HALF SUN AFTN W/AT LEAST AN INCH OR TWO OF SNOWFALL XPCD. && .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 403 AM EST SAT JAN 3 2015 BITTERLY COLD CONDITIONS CAN BE EXPECTED FOR MUCH OF THE LONG TERM FORECAST DURING THE UPCOMING WEEK. STRONG COLD AIR ADVECTION WILL BE OCCURRING AT THE START OF THIS PERIOD SUNDAY NIGHT. A STRONG UPPER LEVEL DISTURBANCE WILL SUPPORT THE DEVELOPMENT OF A CLIPPER TYPE SYSTEM THAT SHOULD RACE ACROSS THE AREA MONDAY NIGHT INTO EARLY TUESDAY. FAVORED THE ECMWF RUN TO RUN CONSISTENCY AND HANDLING OF THIS SYSTEM. TEMPERATURES WILL BE COLD ENOUGH FOR ALL SNOW...WITH 3 TO 6 INCHES EXPECTED BY MID DAY TUESDAY. GIVEN FRESH SNOW COVER AND 850 MB TEMPERATURES DROPPING WELL BELOW -20...OVERNIGHT LOWS SHOULD BE ABLE TO FALL BELOW ZERO. LOWERED TEMPS TUESDAY NIGHT THROUGH THURSDAY NIGHT IN THIS REGARD. WIND CHILLS WILL DIP TO -20 AT TIMES DURING THE MIDDLE OF THE WEEK...WITH ADVISORY CONDITIONS LIKELY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 654 AM EST SAT JAN 3 2015 (FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 134 AM EST SAT JAN 3 2015 LIFR CONDS TO PERSIST THROUGH THE PD AS WIDESPREAD PCPN CONTS INADV OF POTENT SRN STREAM SW EJECTING OUT OF W TX THIS MORNING. RAIN XPCD TO DIMINISH TO DZ LT THIS AFTERNOON AND MUCH OF TONIGHT AS MID LVL DRY SLOT ENVELOPES THE TERMINALS. HWVR LAGGING MID LVL DEFORMATION ZONE AND EWD WRAP OF INTENSE LL CAA WING ALG W/ATTENDANT RAPID INFLUX OF LK MSTR FLUX WILL SPELL A PD OF ACCUMLATING SNOWFALL SUNDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR INZ003>005-008-009-012-014-016>018. WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR INZ006- 007. MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ077- 078. WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR MIZ079>081. OH...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR OHZ004- 005-015-016. WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR OHZ001- 002. LM...GALE WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR LMZ043-046. && $$ UPDATE...FISHER SYNOPSIS...FISHER SHORT TERM...T LONG TERM...SKIPPER AVIATION...T VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
945 AM EST SAT JAN 3 2015 .SYNOPSIS... ISSUED AT 943 AM EST SAT JAN 3 2015 LOW PRESSURE WILL MOVE OUT OF THE SOUTHWEST TOWARDS THE SOUTHERN GREAT LAKES SATURDAY NIGHT. AREAS OF FREEZING RAIN AND SNOW WILL CHANGE TO ALL RAIN BY EARLY AFTERNOON AS TEMPERATURES WARM ABOVE FREEZING. HIGHS TODAY WILL RANGE FROM THE MIDDLE 30S NORTHWEST TO NEAR 50 IN THE SOUTHEAST. && .UPDATE... ISSUED AT 932 AM EST SAT JAN 3 2015 BY IN LARGE GRIDS IN DECENT SHAPE WITH EVENT PRETTY MUCH UNFOLDING AS EXPECTED. REPORTS AT LOCATIONS SOUTH OF ROUTE 24 INDICATE ROADS CONTINUING TO IMPROVE AS TEMPS HOVER IN THE 32 TO 35 DEGREE RANGE. SLICK CONDITIONS STILL BEING REPORTED WITH POCKETS OF FREEZING RAIN BETWEEN 24 AND ROUTE 6 WHERE TEMPS WERE HOVERING IN THE 31 TO 33 DEGREE RANGE WARRANTING CONTINUATION OF THE ADVISORY THROUGH 16Z IN THESE AREAS. FURTHER NORTH...CONDITIONS WILL BE SLOWER TO IMPROVE BUT MAYBE NOT AS BAD AS FEARED YESTERDAY WITH ALL OBS SITES SITTING RIGHT AT FREEZING AS OF 14Z. HOWEVER...NO CHANGES WILL BE MADE TO END TIME OF HEADLINES AT THIS POINT. HAVE MADE MINOR CHANGES TO TEMPS ESPECIALLY SE WHERE READINGS ARE ALREADY HEADING INTO THE MID TO UPR 30S. WILL TAKE ANOTHER LOOK AT HEADLINES IN NEXT HOUR OR 2. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 403 AM EST SAT JAN 3 2015 IMPRESSIVE SRN STREAM SW TROUGH NOTED IN VAPOR THIS MORNING AND BEGINNING TO LIFT OUT OF NM. THIS SYS WILL PHASE QUICKLY TONIGHT W/NRN STREAM SW AMPLIFYING SEWD OUT OF THE NRN ROCKIES RESULTING IN A RAPID NEWD EJECTION INTO SE CANADA BU SUN MORNING. BROAD LOW-MID LVL MSTR SURGE JUST NOW GETTING UP INTO THE AREA W/MORE VIGOROUS PRECIP DVLPMNT NOTED IN COMPOSITE RADAR IMAGERY BACK ACRS CNTRL IL INTO WRN IN AND POSES AN ICING PROB EARLY ON W/CURRENT SFC TEMPS IN THE UPR 20S. HWVR LL WAA QUITE INTENSE AS NOTED OVR SRN IL/IN AND XPCD TO PROGRESS NWD THROUGH THIS MORNING. GIVEN GOOD 00Z CONSENSUS W/CORRESPONDING RUC NOD TO SFC TEMPS CUT BACK TIMING OF ADVISORY ACRS FAR SRN TIER OF COUNTIES YET WILL HOLD W/REMAINDER OF ADVISORY SEGMENTS PER LTL XPCD SFC BASED WARMING WILL OCCUR UNTIL MID-LT MORNING TIED TO DEEPER ERLY FLW TRAJECTORIES AND MUCH LWR THETA-E AIR ORIGINATING FM OLD POLAR RIDGE. REGARDLESS LL WAA WILL OVERWHELM SHALLOW SFC BASED COLD LYR BY LT MORNING/ERLY AFTN S-N W/A DECENT RAIN EVENT XPCD ESP SE HALF. MID LVL DRY SLOT WILL OVERSPREAD AREA LT THIS AFTN WEST AND OVERNIGHT EAST ALTHOUGH TEMPS WILL FAIRLY MILD. EXCEPTION WILL BE FAR WEST WHERE INTENSE LL CAA WING WILL BEGIN TO WRAP SEWD BEHIND DEPARTING SFC LOW. LEFT OVER DEFORMATION ZONE AND RAPID INFLUX OF COLD AIR WILL LEAD TO A RAPID CHG OVR TO ACCUMULATING SNOW FAR NW AND EXPANDING SEWD DURING THE DAY AS MSTR FLUX OFF LK MI TAKES OFF. SHLD SEE A PD OF ROBUST LK ENHANCEMENT THROUGHOUT THE NW HALF SUN AFTN W/AT LEAST AN INCH OR TWO OF SNOWFALL XPCD. && .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 403 AM EST SAT JAN 3 2015 BITTERLY COLD CONDITIONS CAN BE EXPECTED FOR MUCH OF THE LONG TERM FORECAST DURING THE UPCOMING WEEK. STRONG COLD AIR ADVECTION WILL BE OCCURRING AT THE START OF THIS PERIOD SUNDAY NIGHT. A STRONG UPPER LEVEL DISTURBANCE WILL SUPPORT THE DEVELOPMENT OF A CLIPPER TYPE SYSTEM THAT SHOULD RACE ACROSS THE AREA MONDAY NIGHT INTO EARLY TUESDAY. FAVORED THE ECMWF RUN TO RUN CONSISTENCY AND HANDLING OF THIS SYSTEM. TEMPERATURES WILL BE COLD ENOUGH FOR ALL SNOW...WITH 3 TO 6 INCHES EXPECTED BY MID DAY TUESDAY. GIVEN FRESH SNOW COVER AND 850 MB TEMPERATURES DROPPING WELL BELOW -20...OVERNIGHT LOWS SHOULD BE ABLE TO FALL BELOW ZERO. LOWERED TEMPS TUESDAY NIGHT THROUGH THURSDAY NIGHT IN THIS REGARD. WIND CHILLS WILL DIP TO -20 AT TIMES DURING THE MIDDLE OF THE WEEK...WITH ADVISORY CONDITIONS LIKELY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 654 AM EST SAT JAN 3 2015 (FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 134 AM EST SAT JAN 3 2015 LIFR CONDS TO PERSIST THROUGH THE PD AS WIDESPREAD PCPN CONTS INADV OF POTENT SRN STREAM SW EJECTING OUT OF W TX THIS MORNING. RAIN XPCD TO DIMINISH TO DZ LT THIS AFTERNOON AND MUCH OF TONIGHT AS MID LVL DRY SLOT ENVELOPES THE TERMINALS. HWVR LAGGING MID LVL DEFORMATION ZONE AND EWD WRAP OF INTENSE LL CAA WING ALG W/ATTENDANT RAPID INFLUX OF LK MSTR FLUX WILL SPELL A PD OF ACCUMLATING SNOWFALL SUNDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WINTER WEATHER ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR INZ008-009-012>018. WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR INZ006- 007. WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR INZ003>005. MI...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR MIZ079>081. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ077- 078. OH...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR OHZ004- 005-015-016. WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR OHZ001- 002. LM...GALE WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR LMZ043-046. && $$ UPDATE...FISHER SYNOPSIS...FISHER SHORT TERM...T LONG TERM...SKIPPER AVIATION...T VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
700 AM EST SAT JAN 3 2015 .SYNOPSIS... ISSUED AT 400 PM EST FRI JAN 2 2015 LOW PRESSURE WILL MOVE OUT OF THE SOUTHWEST TOWARDS THE SOUTHERN GREAT LAKES SATURDAY NIGHT. A LARGE AREA OF MIXED PRECIPITATION WAS OVERSPREADING THE AREA THIS MORNING AND WILL TRANSITION TO RAIN AS THE MORNING PROGRESSES. HIGHS TODAY WILL RANGE FROM THE MIDDLE 30S NORTHWEST TO NEAR 50 IN THE SOUTHEAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 403 AM EST SAT JAN 3 2015 IMPRESSIVE SRN STREAM SW TROUGH NOTED IN VAPOR THIS MORNING AND BEGINNING TO LIFT OUT OF NM. THIS SYS WILL PHASE QUICKLY TONIGHT W/NRN STREAM SW AMPLIFYING SEWD OUT OF THE NRN ROCKIES RESULTING IN A RAPID NEWD EJECTION INTO SE CANADA BU SUN MORNING. BROAD LOW-MID LVL MSTR SURGE JUST NOW GETTING UP INTO THE AREA W/MORE VIGOROUS PRECIP DVLPMNT NOTED IN COMPOSITE RADAR IMAGERY BACK ACRS CNTRL IL INTO WRN IN AND POSES AN ICING PROB EARLY ON W/CURRENT SFC TEMPS IN THE UPR 20S. HWVR LL WAA QUITE INTENSE AS NOTED OVR SRN IL/IN AND XPCD TO PROGRESS NWD THROUGH THIS MORNING. GIVEN GOOD 00Z CONSENSUS W/CORRESPONDING RUC NOD TO SFC TEMPS CUT BACK TIMING OF ADVISORY ACRS FAR SRN TIER OF COUNTIES YET WILL HOLD W/REMAINDER OF ADVISORY SEGMENTS PER LTL XPCD SFC BASED WARMING WILL OCCUR UNTIL MID-LT MORNING TIED TO DEEPER ERLY FLW TRAJECTORIES AND MUCH LWR THETA-E AIR ORIGINATING FM OLD POLAR RIDGE. REGARDLESS LL WAA WILL OVERWHELM SHALLOW SFC BASED COLD LYR BY LT MORNING/ERLY AFTN S-N W/A DECENT RAIN EVENT XPCD ESP SE HALF. MID LVL DRY SLOT WILL OVERSPREAD AREA LT THIS AFTN WEST AND OVERNIGHT EAST ALTHOUGH TEMPS WILL FAIRLY MILD. EXCEPTION WILL BE FAR WEST WHERE INTENSE LL CAA WING WILL BEGIN TO WRAP SEWD BEHIND DEPARTING SFC LOW. LEFT OVER DEFORMATION ZONE AND RAPID INFLUX OF COLD AIR WILL LEAD TO A RAPID CHG OVR TO ACCUMULATING SNOW FAR NW AND EXPANDING SEWD DURING THE DAY AS MSTR FLUX OFF LK MI TAKES OFF. SHLD SEE A PD OF ROBUST LK ENHANCEMENT THROUGHOUT THE NW HALF SUN AFTN W/AT LEAST AN INCH OR TWO OF SNOWFALL XPCD. && .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 403 AM EST SAT JAN 3 2015 BITTERLY COLD CONDITIONS CAN BE EXPECTED FOR MUCH OF THE LONG TERM FORECAST DURING THE UPCOMING WEEK. STRONG COLD AIR ADVECTION WILL BE OCCURRING AT THE START OF THIS PERIOD SUNDAY NIGHT. A STRONG UPPER LEVEL DISTURBANCE WILL SUPPORT THE DEVELOPMENT OF A CLIPPER TYPE SYSTEM THAT SHOULD RACE ACROSS THE AREA MONDAY NIGHT INTO EARLY TUESDAY. FAVORED THE ECMWF RUN TO RUN CONSISTENCY AND HANDLING OF THIS SYSTEM. TEMPERATURES WILL BE COLD ENOUGH FOR ALL SNOW...WITH 3 TO 6 INCHES EXPECTED BY MID DAY TUESDAY. GIVEN FRESH SNOW COVER AND 850 MB TEMPERATURES DROPPING WELL BELOW -20...OVERNIGHT LOWS SHOULD BE ABLE TO FALL BELOW ZERO. LOWERED TEMPS TUESDAY NIGHT THROUGH THURSDAY NIGHT IN THIS REGARD. WIND CHILLS WILL DIP TO -20 AT TIMES DURING THE MIDDLE OF THE WEEK...WITH ADVISORY CONDITIONS LIKELY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 654 AM EST SAT JAN 3 2015 (FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 134 AM EST SAT JAN 3 2015 LIFR CONDS TO PERSIST THROUGH THE PD AS WIDESPREAD PCPN CONTS INADV OF POTENT SRN STREAM SW EJECTING OUT OF W TX THIS MORNING. RAIN XPCD TO DIMINISH TO DZ LT THIS AFTERNOON AND MUCH OF TONIGHT AS MID LVL DRY SLOT ENVELOPES THE TERMINALS. HWVR LAGGING MID LVL DEFORMATION ZONE AND EWD WRAP OF INTENSE LL CAA WING ALG W/ATTENDANT RAPID INFLUX OF LK MSTR FLUX WILL SPELL A PD OF ACCUMLATING SNOWFALL SUNDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WINTER WEATHER ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR INZ008-009-012>018. WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR INZ006- 007. WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR INZ003>005. MI...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR MIZ079>081. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ077- 078. OH...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR OHZ004- 005-015-016. WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR OHZ001- 002. LM...GALE WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR LMZ043-046. && $$ SYNOPSIS...FISHER SHORT TERM...T LONG TERM...SKIPPER AVIATION...T VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
405 AM EST SAT JAN 3 2015 .SYNOPSIS... ISSUED AT 400 PM EST FRI JAN 2 2015 LOW PRESSURE WILL MOVE OUT OF THE SOUTHWEST TOWARDS THE SOUTHERN GREAT LAKES SATURDAY NIGHT. A LARGE AREA OF MIXED PRECIPITATION WAS OVERSPREADING THE AREA THIS MORNING AND WILL TRANSITION TO RAIN AS THE MORNING PROGRESSES. HIGHS TODAY WILL RANGE FROM THE MIDDLE 30S NORTHWEST TO NEAR 50 IN THE SOUTHEAST. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 403 AM EST SAT JAN 3 2015 IMPRESSIVE SRN STREAM SW TROUGH NOTED IN VAPOR THIS MORNING AND BEGINNING TO LIFT OUT OF NM. THIS SYS WILL PHASE QUICKLY TONIGHT W/NRN STREAM SW AMPLIFYING SEWD OUT OF THE NRN ROCKIES RESULTING IN A RAPID NEWD EJECTION INTO SE CANADA BU SUN MORNING. BROAD LOW-MID LVL MSTR SURGE JUST NOW GETTING UP INTO THE AREA W/MORE VIGOROUS PRECIP DVLPMNT NOTED IN COMPOSITE RADAR IMAGERY BACK ACRS CNTRL IL INTO WRN IN AND POSES AN ICING PROB EARLY ON W/CURRENT SFC TEMPS IN THE UPR 20S. HWVR LL WAA QUITE INTENSE AS NOTED OVR SRN IL/IN AND XPCD TO PROGRESS NWD THROUGH THIS MORNING. GIVEN GOOD 00Z CONSENSUS W/CORRESPONDING RUC NOD TO SFC TEMPS CUT BACK TIMING OF ADVISORY ACRS FAR SRN TIER OF COUNTIES YET WILL HOLD W/REMAINDER OF ADVISORY SEGMENTS PER LTL XPCD SFC BASED WARMING WILL OCCUR UNTIL MID-LT MORNING TIED TO DEEPER ERLY FLW TRAJECTORIES AND MUCH LWR THETA-E AIR ORIGINATING FM OLD POLAR RIDGE. REGARDLESS LL WAA WILL OVERWHELM SHALLOW SFC BASED COLD LYR BY LT MORNING/ERLY AFTN S-N W/A DECENT RAIN EVENT XPCD ESP SE HALF. MID LVL DRY SLOT WILL OVERSPREAD AREA LT THIS AFTN WEST AND OVERNIGHT EAST ALTHOUGH TEMPS WILL FAIRLY MILD. EXCEPTION WILL BE FAR WEST WHERE INTENSE LL CAA WING WILL BEGIN TO WRAP SEWD BEHIND DEPARTING SFC LOW. LEFT OVER DEFORMATION ZONE AND RAPID INFLUX OF COLD AIR WILL LEAD TO A RAPID CHG OVR TO ACCUMULATING SNOW FAR NW AND EXPANDING SEWD DURING THE DAY AS MSTR FLUX OFF LK MI TAKES OFF. SHLD SEE A PD OF ROBUST LK ENHANCEMENT THROUGHOUT THE NW HALF SUN AFTN W/AT LEAST AN INCH OR TWO OF SNOWFALL XPCD. && .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 403 AM EST SAT JAN 3 2015 BITTERLY COLD CONDITIONS CAN BE EXPECTED FOR MUCH OF THE LONG TERM FORECAST DURING THE UPCOMING WEEK. STRONG COLD AIR ADVECTION WILL BE OCCURRING AT THE START OF THIS PERIOD SUNDAY NIGHT. A STRONG UPPER LEVEL DISTURBANCE WILL SUPPORT THE DEVELOPMENT OF A CLIPPER TYPE SYSTEM THAT SHOULD RACE ACROSS THE AREA MONDAY NIGHT INTO EARLY TUESDAY. FAVORED THE ECMWF RUN TO RUN CONSISTENCY AND HANDLING OF THIS SYSTEM. TEMPERATURES WILL BE COLD ENOUGH FOR ALL SNOW...WITH 3 TO 6 INCHES EXPECTED BY MID DAY TUESDAY. GIVEN FRESH SNOW COVER AND 850 MB TEMPERATURES DROPPING WELL BELOW -20...OVERNIGHT LOWS SHOULD BE ABLE TO FALL BELOW ZERO. LOWERED TEMPS TUESDAY NIGHT THROUGH THURSDAY NIGHT IN THIS REGARD. WIND CHILLS WILL DIP TO -20 AT TIMES DURING THE MIDDLE OF THE WEEK...WITH ADVISORY CONDITIONS LIKELY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 134 AM EST SAT JAN 3 2015 VFR CONDS TO START WILL RAPIDLY GO DOWNHILL PRIOR TO DAYBREAK AS PCPN OVERSPREADS THE TERMINALS. UPSTREAM OBS TRENDS DICTATE WIDESPREAD LIFR CONDS DVLPG BY MID MORNING AND CONTG THROUGH MUCH IF NOT ALL OF THIS PD. FZRA NR TERM XPCD TO CHG TO RA SHORTLY AFT DAYBREAK. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WINTER WEATHER ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING FOR INZ008-009-012>018. WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR INZ006- 007. WINTER WEATHER ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR INZ003>005. WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR INZ020-022>027-032>034. MI...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR MIZ079>081. WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ077- 078. OH...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR OHZ004- 005-015-016. WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR OHZ001- 002. WINTER WEATHER ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR OHZ024-025. LM...NONE. && $$ SYNOPSIS...FISHER SHORT TERM...T LONG TERM...SKIPPER AVIATION...T VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSNORTHERNINDIANA WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
529 PM CST SUN JAN 4 2015 ...UPDATED AVIATION DISCUSSION... .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 236 PM CST SUN JAN 4 2015 DRY CONDITIONS ARE EXPECTED TONIGHT THROUGH TOMORROW AS NORTHWEST FLOW WILL BE OBSERVED ABOVE WESTERN KANSAS WITH AN AREA OF HIGH PRESSURE SLIDING EAST OF THE AREA AT THE SURFACE. PARTLY CLOUDY SKIES ARE EXPECTED THIS EVENING WITH INCREASING HIGH CLOUDS EXPECTED TOWARDS SUNRISE TOMORROW. WINDS WILL GENERALLY BE LIGHT AND FROM THE SOUTHEAST TONIGHT SHIFTING TO MORE OF A SOUTHERLY DIRECTION TOMORROW. LOWS TONIGHT LOOK TO DIP INTO THE SINGLE DIGITS WITH HIGHS TOMORROW RANGING FROM THE UPPER 20S ACROSS CENTRAL KANSAS TO UPPER 30S ACROSS THE KS/CO BORDER. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 114 PM CST SUN JAN 4 2015 MONDAY NIGHT WILL START OUT MOSTLY CLEAR, WITH SOUTH WINDS AT 10 MPH OR LESS. THEN AN ARCTIC FRONT WILL PLUNGE DOWN THE PLAINS AND BRING THE FIRST SURGE OF COLDER AIR INTO THE NORTHERN PLAINS. THE GFS AND ECMWF MODELS ARE IN FAIRLY GOOD AGREEMENT AT THE H5 LEVEL THROUGH THE 144 HOUR, AND THEN A WEAK WAVE IN THE 4-CORNERS AREA IS HANDLED DIFFERENT BY EACH MODEL. FOR MONDAY NIGHT, THE UPPER PATTERN OVER WESTERN KANSAS WILL BE NORTHWESTERLY, A DOWN SLOPE AFFECT. BUT, THE STRONG ARCTIC SURFACE HIGH PRESSURE WILL WIN OUT. THIS WILL DROP HIGH TEMPERATURES SEVERAL DEGREES FROM HIGHS ON MONDAY. THEN ON TUESDAY, THE ARCTIC AIR ARRIVES AND WILL GET USHERED IN ON STRONG NORTH WINDS TUESDAY NIGHT. WINDS COULD EASILY BE 20 TO 25 MPH. MINIMUMS TUESDAY NIGHT WILL DIP INTO THE SINGLE DIGITS NORTH OF I-70, AND IN THE 8 TO 10F DEGREE RANGE SOUTH OF HIGHWAY 50. EVEN THOUGH CLOUDS WILL COME IN BEHIND THE FRONT, MAKING WEDNESDAY MOSTLY CLOUDY, VERY STRONG COLD AIR ADVECTION WILL LIMIT HIGHS ON WEDNESDAY TO THE MIDDLE TEENS NORTH OF I-70, THE UPPER TEENS FROM LAKIN TO DODGE CITY TO MEDICINE LODGE, AND THE LOWER 20S FROM SYRACUSE TO LIBERAL TO COLDWATER. THE WINDS WILL BE BLOWING FROM THE NORTH AT 15 TO 20 MPH AND GUSTY MOST OF THE DAY WEDNESDAY, PRODUCING WIND CHILLS FROM MINUS 12 DEGREES IN HAYS TO MINUS 5 DEGREES IN THE MEDICINE LODGE AREA. BY THURSDAY, THE UPPER WAVE TO OUR SOUTHWEST WILL BRING SOME WARMER AIR INTO KANSAS, RAISING HIGHS TO THE MIDDLE 30S TO LOWER 40S. SATURDAY WILL SEE INCREASING LOW AND MID LEVEL MOISTURE, WITH INCREASED CLOUDS AND HIGH TEMPERATURES IN THE UPPER 20S NORTH AROUND HAYS, AND RANGE TO THE MIDDLE 30S DOWN ALONG THE OKLAHOMA BORDER. THERE WILL BE A SLIGHT CHANCE FOR LIGHT SNOW SATURDAY, AND PERHAPS SATURDAY NIGHT. THE WAY THE UPPER WAVE IS TRAVELING OPEN AND TO OUR SOUTH, WE MAY NOT SEE MUCH AT ALL. THE SUPERMODEL PLACED SILENT 12-14 PERCENT POPS ACROSS OUR FORECAST AREA SATURDAY NIGHT, AND I TEND TO AGREE WITH THAT SOLUTION. THE ECMWF MODEL IS MORE REALISTIC WITH THE WAVE ADVANCING FROM THE SOUTHWESTERN U.S., WHICH LEAVES US OUT OF THE SLIGHT CHANCE FOR SNOW. SUNDAY HIGHS SHOULD RANGE FROM THE LOWER TO MIDDLE 30S. MINIMUM TEMPERATURES FROM FRIDAY THROUGH SUNDAY WILL BASICALLY BE FROM 10 DEGREES NORTH OF I-70 TO THE UPPER TEENS ALONG THE OKLAHOMA BORDER. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 525 PM CST SUN JAN 4 2015 NAM BUFR SOUNDINGS INDICATING VEERING WINDS AND MOISTURE INCREASING IN THE 900 TO 850MB LEVEL ACROSS WESTERN KANSAS AFTER MIDNIGHT AS A SURFACE RIDGE AXIS SLOWLY MOVES EAST ACROSS EASTERN KANSAS. HRRR, NAM, AND RAP ALSO SUGGESTING SOME MVFR STATUS DEVELOPING ACROSS PORTIONS OF FAR WESTERN KANSAS DURING THE SAME TIME FRAME. HRRR AND RAP PLACES THE MORE FAVORABLE AREA FOR THIS MVFR CIGS, AND POSSIBLY SOME PATCH FOG, NEAR AND WEST OF THE GCK SO WILL INTRODUCE A PERIOD OF MVFR CEILING AND VISIBILITIES HERE BETWEEN 09Z AND 15Z. NAM EVEN HINTS AT SOME STATUS AND FOG AT DDC AND HYS BUT AT THIS TIME HAVE DECIDED TO KEEP VFR CONDITIONS GOING GIVEN THIS IS THE ONLY MODELS SUGGESTING THIS FURTHER EAST SOLUTION. LIGHT SOUTHERLY WINDS OVERNIGHT WILL INCREASE TO AROUND 15 KNOTS EARLY MONDAY. && .PRELIMINARY POINT TEMPS/POPS... DDC 5 31 14 27 / 0 0 0 0 GCK 5 32 16 28 / 0 0 0 0 EHA 10 36 22 33 / 0 0 0 0 LBL 8 34 15 31 / 0 0 0 0 HYS 2 28 14 22 / 0 0 0 0 P28 7 32 19 28 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HOVORKA_42 LONG TERM...BURKE AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1254 PM EST Sat Jan 3 2015 ...Forecast Update... Issued at 154 PM EST Sat Jan 3 2015 The warm sector is now established over our area with temperatures mainly ranging in the 55 to 60 range. Meanwhile, surface dew points have also climbed into the low and mid 50s across the area. Our relative lull in rain activity will persist another hour or two before rain begins to fill back in from west to east. This will occur ahead of potent energy beginning to eject out of the Red River Valley. Our best forcing and precipitable water airmass (~1.5") will arrive later this evening bringing widespread and occasionally heavy rain to the area. Scattered embedded thunderstorms are also expected. Expect surface temperatures to slowly rise through the afternoon and evening on the advective component, which will result in a slighly unstable near surface across our southern CWA. The warm nose aloft will prevent any real surface based destabilization, however gusty winds could be mixed down to the surface in stronger showers and storms. Will watch out for this overnight. The main threat will be a local hydro problem due to the heavy rain, however widespread problems are not anticipated. Will keep the 1 to 2 inches of rain for the event forecast. Previous Update... Issued at 1000 AM EST Sat Jan 3 2015 The warm front is rapidly pushing northward at this hour and will be through our northern CWA by early afternoon. Current obs show BWG at 56/54 with SDF at 46/44. Have seen a surge in showers and scattered thunderstorms west of I-65 on the nose of the 50-60 knot low level jet. These showers are basically signaling the warm frontal passage. Did go ahead and increase thunder coverage to scattered as several lightning strikes are showing up. Otherwise, current forecast is on track and have only updated to reflect the latest temp, dewpoint, wind and precipitation coverage trends. .SHORT TERM (Now through Sunday)... Issued at 300 AM EST Sat Jan 3 2015 Latest water vapor imagery with 500 mb RAP heights shows a deep closed low across southern New Mexico while a ridge lies off the Florida coast. In between, broad southwesterly flow has been bringing a very moist and warm air mass into the Ohio Valley. At the surface, high pressure is departing the region, allowing a warm front to lift through TN and KY. Early morning temperatures range from the upper 30s across southern IN to upper 40s across southern KY. As a surface low deepens to our west, plan on the warm front to lift through Kentucky this morning and reach southern Indiana by early afternoon. As the region becomes well within the warm sector, temperatures will top out right around 60 degrees for much of the area. Southern Kentucky locations are most likely to get into the lower 60s. Southerly winds will increase throughout the day as well, as soundings show a rather strong 850 mb jet of 55+ knots at about 2-3kft. An inversion in the lowest levels of the atmosphere should keep these strong winds from mixing down, but it will still be gusty at times today. Precipitation this morning is expected to be on the lighter side, mainly in the form of drizzle or light rain showers. Precipitation chances/coverage will then steadily increase today as isentropic upglide picks up and the region becomes more in the nose of the 850mb moisture transport axis. The greatest forcing/lift arrives by mid/late afternoon through the evening hours as the cold front swings through the state. Just ahead of this front, PWATs climb to 1.6 inches, which would be record values for this time of year for BNA/ILN. Overall, a very moist air mass will be in place and though the system is expected to be progressive, any training showers will be capable of some moderate to locally heavy rainfall, especially across the southern forecast area. Plan on rainfall amounts to range from 1.5 to locally 2 inches across the area through Sunday morning. Thunder chances are still included in the forecast as MUCAPE values are progged to be around 500 J/kg this afternoon. Tonight`s low will be quite mild, held up due to lingering precipitation and southerly flow. Plan on readings to only into the mid 40s to lower 50s, warmest east of I-65. Cold air advection kicks in between midnight and sunrise Sunday, resulting in a steady drop in temperatures during the day Sunday. Morning readings in the mid 40s to near 50 are expected to fall into the mid 30s to around 40 by mid/late afternoon. At the same time, 03.00z guidance continues to show lingering wrap around moisture behind the departing low pressure system. As temperatures aloft reach -8 to -10c, there may be enough saturation left to squeeze out a few snowflakes across southern Indiana and northern Kentucky. Otherwise, Sunday afternoon will be noticeably colder especially given cloudy skies and a brisk west/northwest wind 15-20 mph, making it feel more like the middle 20s at times. .LONG TERM (Sunday night through Friday)... Issued at 257 AM EST Sat Jan 3 2015 ...Very Cold Temperatures and Wind Chills Mid-Week... Canadian high pressure crossing the region Sunday night and Monday will bring a quick shot of chilly air. Low clouds will likely hang around for much of the night Sunday night, but should clear out just in time to allow sunrise readings to drop into the 15-20 degree range. We`ll have sunshine on Monday but the mercury will only recover into the middle 20s in southern Indiana and around 30 in Kentucky. A quick moving clipper type system will zip by to our north Monday night/Tuesday. The models have trended slightly faster and farther south with this feature. Looking at atmospheric cross-sections, even in the northernmost reaches of the LMK CWA around Madison, there`s quite a bit of dry low level air Monday night, and then on Tuesday when some low level moisture does move in it`s very shallow. So, it still appears, at least for now, that measurable precipitation is unlikely with this system. Will, however, include a chance of flurries generally north of a Salem-Frankfort-Carlisle line. Also, it should be noted that the GEM brings accumulating snows to southern Indiana and northern Kentucky late Monday night. This solution is an outlier, but these types of systems can do surprising things sometimes, so it`s still something to keep an eye on. Strong Canadian high pressure will then invade Tuesday night through Thursday. A tight surface pressure gradient on the nose of the incoming high pressure Wednesday could give us some afternoon gusts around 20 mph. With temperatures reaching only into the teens in southern Indiana and the 20s in Kentucky, Wednesday will be a cold day. Then it will get worse. Lows Wednesday night, as the cold heart of the Canadian high moves in, will be in the 0 to 5 degree range. Add to that a northwest breeze around 10 mph and we could be looking at advisory level wind chills of 10 to 15 degrees below zero as the kids head out to the bus stops Thursday morning. Highs Thursday afternoon will struggle to reach 20. A cold front will sweep through the Ohio and Tennessee Valleys Thursday night/Friday. However, the Gulf of Mexico will be completely shut off by the departing mid-week high, so no precipitation is expected. && .AVIATION (18Z TAF Update)... Issued at 1209 PM EST Sat Jan 3 2015 The warm front has lifted north of the TAF sites with all locations currently experiencing steady to gusting south winds. With the arrival of the warm sector, ceilings have improved to MVFR, however will likely remain below fuel-alternate. Expect these improved ceilings and relatively dry conditions to continue for a few hours this afternoon before another surge in showers and thunderstorms arrives by mid to late afternoon. A fairly prolonged period of moderate to briefly heavy rain is then possible through the evening hours, with SDF having the best chance at getting gapped by two surges in moisture. Will continue to mention VCTS/CB through the evening hours. Otherwise, the bulk of the heavy rain ends around or just after Midnight EST, with a cold front passing through thereafter. Winds will swing around to WSW then almost westerly with gusty winds as high as 30-35 mph at times on Sunday. Only other issue will be ongoing LLWS threat below 2 K feet as a 50-60 knot low level jet streams overhead. This threat should diminish as we head into the late afternoon hours as the jet swings east. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........BJS Short Term.....ZBT Long Term......13 Aviation.......BJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1211 PM EST Sat Jan 3 2015 ...Updated Aviation Discussion... ...Forecast Update... Issued at 1000 AM EST Fri Jan 2 2015 The warm front is rapidly pushing northward at this hour and will be through our northern CWA by early afternoon. Current obs show BWG at 56/54 with SDF at 46/44. Have seen a surge in showers and scattered thunderstorms west of I-65 on the nose of the 50-60 knot low level jet. These showers are basically signaling the warm frontal passage. Did go ahead and increase thunder coverage to scattered as several lightning strikes are showing up. Otherwise, current forecast is on track and have only updated to reflect the latest temp, dewpoint, wind and precipitation coverage trends. .SHORT TERM (Now through Sunday)... Issued at 300 AM EST Sat Jan 3 2015 Latest water vapor imagery with 500 mb RAP heights shows a deep closed low across southern New Mexico while a ridge lies off the Florida coast. In between, broad southwesterly flow has been bringing a very moist and warm air mass into the Ohio Valley. At the surface, high pressure is departing the region, allowing a warm front to lift through TN and KY. Early morning temperatures range from the upper 30s across southern IN to upper 40s across southern KY. As a surface low deepens to our west, plan on the warm front to lift through Kentucky this morning and reach southern Indiana by early afternoon. As the region becomes well within the warm sector, temperatures will top out right around 60 degrees for much of the area. Southern Kentucky locations are most likely to get into the lower 60s. Southerly winds will increase throughout the day as well, as soundings show a rather strong 850 mb jet of 55+ knots at about 2-3kft. An inversion in the lowest levels of the atmosphere should keep these strong winds from mixing down, but it will still be gusty at times today. Precipitation this morning is expected to be on the lighter side, mainly in the form of drizzle or light rain showers. Precipitation chances/coverage will then steadily increase today as isentropic upglide picks up and the region becomes more in the nose of the 850mb moisture transport axis. The greatest forcing/lift arrives by mid/late afternoon through the evening hours as the cold front swings through the state. Just ahead of this front, PWATs climb to 1.6 inches, which would be record values for this time of year for BNA/ILN. Overall, a very moist air mass will be in place and though the system is expected to be progressive, any training showers will be capable of some moderate to locally heavy rainfall, especially across the southern forecast area. Plan on rainfall amounts to range from 1.5 to locally 2 inches across the area through Sunday morning. Thunder chances are still included in the forecast as MUCAPE values are progged to be around 500 J/kg this afternoon. Tonight`s low will be quite mild, held up due to lingering precipitation and southerly flow. Plan on readings to only into the mid 40s to lower 50s, warmest east of I-65. Cold air advection kicks in between midnight and sunrise Sunday, resulting in a steady drop in temperatures during the day Sunday. Morning readings in the mid 40s to near 50 are expected to fall into the mid 30s to around 40 by mid/late afternoon. At the same time, 03.00z guidance continues to show lingering wrap around moisture behind the departing low pressure system. As temperatures aloft reach -8 to -10c, there may be enough saturation left to squeeze out a few snowflakes across southern Indiana and northern Kentucky. Otherwise, Sunday afternoon will be noticeably colder especially given cloudy skies and a brisk west/northwest wind 15-20 mph, making it feel more like the middle 20s at times. .LONG TERM (Sunday night through Friday)... Issued at 257 AM EST Sat Jan 3 2015 ...Very Cold Temperatures and Wind Chills Mid-Week... Canadian high pressure crossing the region Sunday night and Monday will bring a quick shot of chilly air. Low clouds will likely hang around for much of the night Sunday night, but should clear out just in time to allow sunrise readings to drop into the 15-20 degree range. We`ll have sunshine on Monday but the mercury will only recover into the middle 20s in southern Indiana and around 30 in Kentucky. A quick moving clipper type system will zip by to our north Monday night/Tuesday. The models have trended slightly faster and farther south with this feature. Looking at atmospheric cross-sections, even in the northernmost reaches of the LMK CWA around Madison, there`s quite a bit of dry low level air Monday night, and then on Tuesday when some low level moisture does move in it`s very shallow. So, it still appears, at least for now, that measurable precipitation is unlikely with this system. Will, however, include a chance of flurries generally north of a Salem-Frankfort-Carlisle line. Also, it should be noted that the GEM brings accumulating snows to southern Indiana and northern Kentucky late Monday night. This solution is an outlier, but these types of systems can do surprising things sometimes, so it`s still something to keep an eye on. Strong Canadian high pressure will then invade Tuesday night through Thursday. A tight surface pressure gradient on the nose of the incoming high pressure Wednesday could give us some afternoon gusts around 20 mph. With temperatures reaching only into the teens in southern Indiana and the 20s in Kentucky, Wednesday will be a cold day. Then it will get worse. Lows Wednesday night, as the cold heart of the Canadian high moves in, will be in the 0 to 5 degree range. Add to that a northwest breeze around 10 mph and we could be looking at advisory level wind chills of 10 to 15 degrees below zero as the kids head out to the bus stops Thursday morning. Highs Thursday afternoon will struggle to reach 20. A cold front will sweep through the Ohio and Tennessee Valleys Thursday night/Friday. However, the Gulf of Mexico will be completely shut off by the departing mid-week high, so no precipitation is expected. && .AVIATION (18Z TAF Update)... Issued at 1209 PM EST Sat Jan 3 2015 The warm front has lifted north of the TAF sites with all locations currently experiencing steady to gusting south winds. With the arrival of the warm sector, ceilings have improved to MVFR, however will likely remain below fuel-alternate. Expect these improved ceilings and relatively dry conditions to continue for a few hours this afternoon before another surge in showers and thunderstorms arrives by mid to late afternoon. A fairly prolonged period of moderate to briefly heavy rain is then possible through the evening hours, with SDF having the best chance at getting gapped by two surges in moisture. Will continue to mention VCTS/CB through the evening hours. Otherwise, the bulk of the heavy rain ends around or just after Midnight EST, with a cold front passing through thereafter. Winds will swing around to WSW then almost westerly with gusty winds as high as 30-35 mph at times on Sunday. Only other issue will be ongoing LLWS threat below 2 K feet as a 50-60 knot low level jet streams overhead. This threat should diminish as we head into the late afternoon hours as the jet swings east. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........BJS Short Term.....ZBT Long Term......13 Aviation.......BJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1002 AM EST Sat Jan 3 2015 ...Forecast Update... Issued at 1000 AM EST Fri Jan 2 2015 The warm front is rapidly pushing northward at this hour and will be through our northern CWA by early afternoon. Current obs show BWG at 56/54 with SDF at 46/44. Have seen a surge in showers and scattered thunderstorms west of I-65 on the nose of the 50-60 knot low level jet. These showers are basically signaling the warm frontal passage. Did go ahead and increase thunder coverage to scattered as several lightning strikes are showing up. Otherwise, current forecast is on track and have only updated to reflect the latest temp, dewpoint, wind and precipitation coverage trends. .SHORT TERM (Now through Sunday)... Issued at 300 AM EST Sat Jan 3 2015 Latest water vapor imagery with 500 mb RAP heights shows a deep closed low across southern New Mexico while a ridge lies off the Florida coast. In between, broad southwesterly flow has been bringing a very moist and warm air mass into the Ohio Valley. At the surface, high pressure is departing the region, allowing a warm front to lift through TN and KY. Early morning temperatures range from the upper 30s across southern IN to upper 40s across southern KY. As a surface low deepens to our west, plan on the warm front to lift through Kentucky this morning and reach southern Indiana by early afternoon. As the region becomes well within the warm sector, temperatures will top out right around 60 degrees for much of the area. Southern Kentucky locations are most likely to get into the lower 60s. Southerly winds will increase throughout the day as well, as soundings show a rather strong 850 mb jet of 55+ knots at about 2-3kft. An inversion in the lowest levels of the atmosphere should keep these strong winds from mixing down, but it will still be gusty at times today. Precipitation this morning is expected to be on the lighter side, mainly in the form of drizzle or light rain showers. Precipitation chances/coverage will then steadily increase today as isentropic upglide picks up and the region becomes more in the nose of the 850mb moisture transport axis. The greatest forcing/lift arrives by mid/late afternoon through the evening hours as the cold front swings through the state. Just ahead of this front, PWATs climb to 1.6 inches, which would be record values for this time of year for BNA/ILN. Overall, a very moist air mass will be in place and though the system is expected to be progressive, any training showers will be capable of some moderate to locally heavy rainfall, especially across the southern forecast area. Plan on rainfall amounts to range from 1.5 to locally 2 inches across the area through Sunday morning. Thunder chances are still included in the forecast as MUCAPE values are progged to be around 500 J/kg this afternoon. Tonight`s low will be quite mild, held up due to lingering precipitation and southerly flow. Plan on readings to only into the mid 40s to lower 50s, warmest east of I-65. Cold air advection kicks in between midnight and sunrise Sunday, resulting in a steady drop in temperatures during the day Sunday. Morning readings in the mid 40s to near 50 are expected to fall into the mid 30s to around 40 by mid/late afternoon. At the same time, 03.00z guidance continues to show lingering wrap around moisture behind the departing low pressure system. As temperatures aloft reach -8 to -10c, there may be enough saturation left to squeeze out a few snowflakes across southern Indiana and northern Kentucky. Otherwise, Sunday afternoon will be noticeably colder especially given cloudy skies and a brisk west/northwest wind 15-20 mph, making it feel more like the middle 20s at times. .LONG TERM (Sunday night through Friday)... Issued at 257 AM EST Sat Jan 3 2015 ...Very Cold Temperatures and Wind Chills Mid-Week... Canadian high pressure crossing the region Sunday night and Monday will bring a quick shot of chilly air. Low clouds will likely hang around for much of the night Sunday night, but should clear out just in time to allow sunrise readings to drop into the 15-20 degree range. We`ll have sunshine on Monday but the mercury will only recover into the middle 20s in southern Indiana and around 30 in Kentucky. A quick moving clipper type system will zip by to our north Monday night/Tuesday. The models have trended slightly faster and farther south with this feature. Looking at atmospheric cross-sections, even in the northernmost reaches of the LMK CWA around Madison, there`s quite a bit of dry low level air Monday night, and then on Tuesday when some low level moisture does move in it`s very shallow. So, it still appears, at least for now, that measurable precipitation is unlikely with this system. Will, however, include a chance of flurries generally north of a Salem-Frankfort-Carlisle line. Also, it should be noted that the GEM brings accumulating snows to southern Indiana and northern Kentucky late Monday night. This solution is an outlier, but these types of systems can do surprising things sometimes, so it`s still something to keep an eye on. Strong Canadian high pressure will then invade Tuesday night through Thursday. A tight surface pressure gradient on the nose of the incoming high pressure Wednesday could give us some afternoon gusts around 20 mph. With temperatures reaching only into the teens in southern Indiana and the 20s in Kentucky, Wednesday will be a cold day. Then it will get worse. Lows Wednesday night, as the cold heart of the Canadian high moves in, will be in the 0 to 5 degree range. Add to that a northwest breeze around 10 mph and we could be looking at advisory level wind chills of 10 to 15 degrees below zero as the kids head out to the bus stops Thursday morning. Highs Thursday afternoon will struggle to reach 20. A cold front will sweep through the Ohio and Tennessee Valleys Thursday night/Friday. However, the Gulf of Mexico will be completely shut off by the departing mid-week high, so no precipitation is expected. && .AVIATION (12Z TAF Update)... Issued at 618 AM EST Sat Jan 3 2015 IFR/LIFR ceilings to persist at all TAF sites today as a warm front lifts from TN through KY into Indiana later this afternoon. Widespread showers/drizzle will mainly impact SDF/LEX this morning but large band of showers and embedded thunderstorms currently across AR/MO will slide east over the area this afternoon and evening. LLWS threat will continue past sunrise today through the afternoon hours as there will be a very strong 2000 ft jet /southwest at 55 kts/ with southeast surface winds at 10 kts. Toward the end of the period, a cold front will pass through, shifting winds to the west. Moisture trapped in the low levels will keep IFR to low-end MVFR ceilings in place. Weakening but still strong 850 mb jet may allow higher winds to mix down post front as well, with gusts up to 30-35 mph possible. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........BJS Short Term.....ZBT Long Term......13 Aviation.......ZBT
AREA FORECAST DISCUSSION
NWS JACKSON KY
735 AM EST SAT JAN 3 2015 .UPDATE... ISSUED AT 735 AM EST SAT JAN 3 2015 UPDATED THE GRIDS TO REFLECT THE LATEST RADAR TRENDS AND HRRR DATA. ALSO REFINED THE T AND TD GRIDS FOR THE NEXT SEVERAL HOURS PER THE LATEST OBS AND TRENDS. THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 335 AM EST SAT JAN 3 2015 08Z SFC ANALYSIS SHOWS A WARM FRONT LIFTING THROUGH EASTERN KENTUCKY IN CONJUNCTION WITH AN AREA OF LOW PRESSURE DEVELOPING TO THE SOUTHWEST. SOME LIGHT RAIN SHOWERS HAVE BEEN ASSOCIATED WITH THIS BOUNDARY ALONG WITH PATCHES OF FOG AND LOW CIGS. TEMPERATURES ARE RATHER MILD ACROSS THE AREA WITH MID 30S FOUND NORTH OF THE FRONT AND LOW 40S TO THE SOUTH OF IT. DEWPOINTS THROUGH THE AREA ARE WITHIN A DEGREE OR TWO OF THE AIR TEMPERATURE. THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST. THEY ALL DEPICT A CLOSED LOW CURRENTLY OVER SOUTHERN NEW MEXICO BEING PICKED UP BY THE NORTHERN STREAM FLOW TODAY AND MOVING THROUGH THE OHIO VALLEY ON SUNDAY AS A FULL LATITUDE TROUGH. THE LATEST ECMWF AND NAM ARE THE MOST SIMILAR WITH THIS TRANSITION AND WERE LEANED ON MOST FOR THIS FORECAST. IN ADDITION...THE LATEST HRRR WAS INCORPORATED INTO THE NEAR TERM PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE A RATHER WARM EARLY JANUARY DAY ACROSS EASTERN KENTUCKY AS SCATTERED SHOWERS MOVE THROUGH DURING THE MORNING HOURS. AN INVERSION WILL KEEP THE GUSTY WINDS JUST OFF THE SFC FROM AFFECTING THOSE OF US AT GROUND LEVEL. HOWEVER...THIS COULD BREAK BY AFTERNOON AND BRING SOME OF THOSE GUSTY WINDS TO THE SFC. IN ADDITION...THE DEEPENING LOW TO THE WEST AND ITS WARM FRONT NORTH OF THE AREA WILL SET THE STAGE FOR A POTENTIAL OF MAINLY ELEVATED THUNDERSTORMS...THOUGH THEY COULD BECOME SFC BASED...ESPECIALLY IF THE CLOUDS THIN OR BREAK OVER THIS PART OF THE STATE LATER TODAY. THE HIGHEST POPS AND STEADIER RAINS SHOULD STAY WEST OF THE AREA FOR MUCH OF THE DAY...THOUGH IF ANY BANDS DO SET UP AHEAD OF THE COLD FRONT WE COULD SEE HEAVY TO EXCESSIVE RAINS GIVEN THE VERY HIGH PWATS FOR THIS PART OF THE YEAR. MOST LIKELY...THOUGH...THE BEST RAINS WILL STAY TO THE WEST OF THE AREA...CLOSER TO THE CORE OF THE SYSTEM...UNTIL LATER IN THE EVENING AND OVERNIGHT WHEN THE COLD FRONT LUNGES THIS WAY. WITH THIS PASSAGE...EXPECT A PERIOD OF HEAVY RAIN AND POSSIBLE THUNDERSTORMS ALONG WITH GUSTY SOUTHWEST WINDS. AT THIS POINT WILL HOLD OFF ON ANY FLOOD WATCHES GIVEN THE EXPECTATION OF DOWNSLOPING IN THE EAST AND SOME DRY SLOTTING AHEAD OF THE COLD FRONT. THE POTENTIAL FOR HEAVY RAINS TONIGHT WILL BE HIT HARD IN THE HWO ALONG WITH THE CONCERN FOR GUSTY WINDS. THE FRONT GOES THROUGH SHORTLY AFTER 12Z SUNDAY WITH FALLING TEMPERATURES EXPECTED THROUGH THE REST OF THE DAY. WOULD ALSO EXPECT SOME WRAP AROUND AND UPSLOPE PCPN TO DEVELOP IN THE FRONT/S WAKE LATER IN THE AFTERNOON. THIS...COMBINED WITH FALLING TEMPERATURES...WILL LIKELY RESULT IN SOME LIGHT SNOW SHOWERS AROUND THE AREA INTO SUNDAY EVENING. WHILE NO ACCUMULATIONS ARE EXPECTED FROM THIS...THERE COULD BE BRIEF DUSTINGS WHERE ANY HEALTHY SNOW SHOWER PASSES. WILL ADD THIS FLEETING SNOW POTENTIAL TO THE HWO...AS WELL. AGAIN USED THE BCCONSSHORT AS A STARTING POINT FOR TEMPS...TD...AND WINDS THROUGH 21Z TODAY AND THEN THE SUPERBLEND THROUGH 00Z MONDAY. ONLY SLIGHTLY TWEAKED POINT TEMPERATURE DATA FOR MAXES AND MINS. AS FOR POPS...FAVORED A BLEND OF THE HRRR AND NAM12 EARLY THEN MAINLY THE NAM12 TONIGHT INTO SUNDAY. GENERALLY UNDERCUT MOS TODAY... ESPECIALLY EAST...WENT CATEGORICAL TONIGHT...AND THEN ENDED UP HIGHER THAN MOS FOR SUNDAY AFTERNOON AND EVENING. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 340 AM EST SAT JAN 3 2015 THE UPPER LEVEL PATTERN THROUGH THE EXTENDED FORECAST PERIOD WILL FEATURE A BROAD TROUGH OVER THE GREAT LAKES AND NEW ENGLAND REGIONS WITH A SERIES OF SHORTWAVES ROUNDING THE BASE OF THE TROUGH AND MOVING THROUGH THE LOWER GREAT LAKES AND OH VALLEY REGION. TOWARDS THE END OF THE EXTENDED PORTION OF THE FORECAST ON THURSDAY AND INTO FRIDAY A STRONG JET STREAK DIVES SOUTHEAST OUT OF CENTRAL CANADA AND INTO THE LOWER TN VALLEY AS THE LONGWAVE TROUGH OVER THE EASTERN CONUS DEEPENS AND A POTENT SHORTWAVE MOVES THROUGH THE MID ATLANTIC STATES AND OFF THE ATLANTIC COAST. FOR THE MOST PART...THE MODELS AGREE WITH WITH THE OVERALL PROGRESSION OF THE LONGWAVE PATTERN. CLOSER TO THE SURFACE...A COLD FRONT WILL EXIT EASTERN KENTUCKY ON SUNDAY NIGHT WITH SOME WRAP AROUND MOISTURE...THOUGH SHALLOW...MAKING IT THROUGH EASTERN KENTUCKY. WITH THE COLDER AIR FILTERING INTO THE AREA IN EARNEST...THIS WILL RESULT INTO A CHANGE OVER TO SOME SNOW SHOWERS AND IS EXPECTED TO BE SHORT IN DURATION AS THE MOISTURE AND UPPER TROUGH WILL BE QUICK TO EXIT. DO NOT EXPECT MORE THAN A DUSTING WITH THIS ACTIVITY. COLDER AIR WILL BE WELL ENTRENCHED THROUGH THE AREA FOR MONDAY AND TUESDAY AND ESPECIALLY THROUGH THE REST OF THE EXTENDED. THE NEXT COLD FRONT WILL PUSH THROUGH THE OH VALLEY ON TUESDAY AND TUESDAY NIGHT. IN NORTHWEST FLOW...THE BEST MOISTURE AND LIFT WITH THIS FEATURE APPEARS TO BE NORTH OF THE OH RIVER AND THEREFORE LITTLE PRECIP POSSIBLE INTO EASTERN KENTUCKY. THIS THINKING IS INLINE WITH THE RESULT OF THE ALL MODEL BLEND AND AS SUCH HAVE STAYED WITH A DRY FORECAST. DID GO WITH SOME FLURRIES IN THE VERY NORTH THOUGH WITH NO MEASURABLE PRECIP EXPECTED. THIS FRONT MOVES THROUGH TUESDAY NIGHT AND QUITE AN ARCTIC AIRMASS FOLLOWS IN BEHIND THIS FEATURE. ARCTIC HIGH PRESSURE WILL MOVE SOUTHEAST INTO THE LOWER MS RIVER VALLEY AND WITH IT...SOME VERY COLD AND DRY AIR. THIS WILL KEEP EASTERN KENTUCKY DRY FOR THE REST OF THE EXTENDED FORECAST PERIOD AND BRING SOME NEAR ZERO TEMPERATURES FOR THURSDAY MORNING AND DRY AIR. DEW POINTS FOR THURSDAY WILL DROP INTO THE NEGATIVE DIGITS AND ONLY RISE INTO THE TEENS FOR FRIDAY. A COLD AND DRY TREND WILL BE IN STORE FOR THE END OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 715 AM EST SAT JAN 3 2015 MVFR CIGS HAVE OVERTAKEN THE EASTERN KENTUCKY SITES THIS MORNING WITH A FEW PATCHES OF LOWER VIS AND CIGS CLOSER TO THE WARM FRONT. EXPECT CIGS TO BOUNCE BETWEEN LOW VFR AND MVFR THROUGH THE DAY WITH SCATTERED SHOWERS AROUND. THINGS GET MORE INTERESTING IN THE AFTERNOON WHEN THE INVERSION SHOULD BREAK FOR MOST PLACES ALLOWING SCATTERED SHOWERS TO BECOME MORE ROBUST WITH A POTENTIAL FOR STRAY THUNDERSTORMS. HOWEVER...THE MAIN CONCERN WILL BE WITH THE ACTUAL COLD FRONT PASSING THROUGH LATER TONIGHT WITH A POTENTIAL FOR A SQUALL LINE OF HEAVIER RAIN AND LOW CIGS/VIS ALONG WITH THUNDER. ANOTHER CONCERN IS LLWS THROUGH MIDDAY AS WINDS INCREASE JUST OFF THE SURFACE TO BETWEEN 40 AND 45 KNOTS THIS MORNING. DO EXPECT SOME MIXING OF THE GUSTS TO THE SFC LATER THIS AFTERNOON...ESPECIALLY IF SOME BREAKS IN THE SKY COVER OCCUR AS WE SIT IN THE DEVELOPING SYSTEM/S WARM SECTOR. OTHERWISE...WINDS WILL PICK UP BY AFTERNOON FROM THE SOUTH AT 10 TO 20 KTS WITH HIGHER GUSTS POSSIBLE THROUGH THE AFTERNOON AND INTO THE EVENING. THE WINDS CONTINUE TO BE BREEZY TONIGHT AS THEY TURN MORE TO THE SOUTHWEST. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
623 AM EST Sat Jan 3 2015 .SHORT TERM (Now through Sunday)... Issued at 300 AM EST Sat Jan 3 2015 Latest water vapor imagery with 500 mb RAP heights shows a deep closed low across southern New Mexico while a ridge lies off the Florida coast. In between, broad southwesterly flow has been bringing a very moist and warm air mass into the Ohio Valley. At the surface, high pressure is departing the region, allowing a warm front to lift through TN and KY. Early morning temperatures range from the upper 30s across southern IN to upper 40s across southern KY. As a surface low deepens to our west, plan on the warm front to lift through Kentucky this morning and reach southern Indiana by early afternoon. As the region becomes well within the warm sector, temperatures will top out right around 60 degrees for much of the area. Southern Kentucky locations are most likely to get into the lower 60s. Southerly winds will increase throughout the day as well, as soundings show a rather strong 850 mb jet of 55+ knots at about 2-3kft. An inversion in the lowest levels of the atmosphere should keep these strong winds from mixing down, but it will still be gusty at times today. Precipitation this morning is expected to be on the lighter side, mainly in the form of drizzle or light rain showers. Precipitation chances/coverage will then steadily increase today as isentropic upglide picks up and the region becomes more in the nose of the 850mb moisture transport axis. The greatest forcing/lift arrives by mid/late afternoon through the evening hours as the cold front swings through the state. Just ahead of this front, PWATs climb to 1.6 inches, which would be record values for this time of year for BNA/ILN. Overall, a very moist air mass will be in place and though the system is expected to be progressive, any training showers will be capable of some moderate to locally heavy rainfall, especially across the southern forecast area. Plan on rainfall amounts to range from 1.5 to locally 2 inches across the area through Sunday morning. Thunder chances are still included in the forecast as MUCAPE values are progged to be around 500 J/kg this afternoon. Tonight`s low will be quite mild, held up due to lingering precipitation and southerly flow. Plan on readings to only into the mid 40s to lower 50s, warmest east of I-65. Cold air advection kicks in between midnight and sunrise Sunday, resulting in a steady drop in temperatures during the day Sunday. Morning readings in the mid 40s to near 50 are expected to fall into the mid 30s to around 40 by mid/late afternoon. At the same time, 03.00z guidance continues to show lingering wrap around moisture behind the departing low pressure system. As temperatures aloft reach -8 to -10c, there may be enough saturation left to squeeze out a few snowflakes across southern Indiana and northern Kentucky. Otherwise, Sunday afternoon will be noticeably colder especially given cloudy skies and a brisk west/northwest wind 15-20 mph, making it feel more like the middle 20s at times. .LONG TERM (Sunday night through Friday)... Issued at 257 AM EST Sat Jan 3 2015 ...Very Cold Temperatures and Wind Chills Mid-Week... Canadian high pressure crossing the region Sunday night and Monday will bring a quick shot of chilly air. Low clouds will likely hang around for much of the night Sunday night, but should clear out just in time to allow sunrise readings to drop into the 15-20 degree range. We`ll have sunshine on Monday but the mercury will only recover into the middle 20s in southern Indiana and around 30 in Kentucky. A quick moving clipper type system will zip by to our north Monday night/Tuesday. The models have trended slightly faster and farther south with this feature. Looking at atmospheric cross-sections, even in the northernmost reaches of the LMK CWA around Madison, there`s quite a bit of dry low level air Monday night, and then on Tuesday when some low level moisture does move in it`s very shallow. So, it still appears, at least for now, that measurable precipitation is unlikely with this system. Will, however, include a chance of flurries generally north of a Salem-Frankfort-Carlisle line. Also, it should be noted that the GEM brings accumulating snows to southern Indiana and northern Kentucky late Monday night. This solution is an outlier, but these types of systems can do surprising things sometimes, so it`s still something to keep an eye on. Strong Canadian high pressure will then invade Tuesday night through Thursday. A tight surface pressure gradient on the nose of the incoming high pressure Wednesday could give us some afternoon gusts around 20 mph. With temperatures reaching only into the teens in southern Indiana and the 20s in Kentucky, Wednesday will be a cold day. Then it will get worse. Lows Wednesday night, as the cold heart of the Canadian high moves in, will be in the 0 to 5 degree range. Add to that a northwest breeze around 10 mph and we could be looking at advisory level wind chills of 10 to 15 degrees below zero as the kids head out to the bus stops Thursday morning. Highs Thursday afternoon will struggle to reach 20. A cold front will sweep through the Ohio and Tennessee Valleys Thursday night/Friday. However, the Gulf of Mexico will be completely shut off by the departing mid-week high, so no precipitation is expected. && .AVIATION (12Z TAF Update)... Issued at 618 AM EST Sat Jan 3 2015 IFR/LIFR ceilings to persist at all TAF sites today as a warm front lifts from TN through KY into Indiana later this afternoon. Widespread showers/drizzle will mainly impact SDF/LEX this morning but large band of showers and embedded thunderstorms currently across AR/MO will slide east over the area this afternoon and evening. LLWS threat will continue past sunrise today through the afternoon hours as there will be a very strong 2000 ft jet /southwest at 55 kts/ with southeast surface winds at 10 kts. Toward the end of the period, a cold front will pass through, shifting winds to the west. Moisture trapped in the low levels will keep IFR to low-end MVFR ceilings in place. Weakening but still strong 850 mb jet may allow higher winds to mix down post front as well, with gusts up to 30-35 mph possible. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Short Term........ZBT Long Term.........13 Aviation..........ZBT
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
343 AM EST SAT JAN 3 2015 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 335 AM EST SAT JAN 3 2015 08Z SFC ANALYSIS SHOWS A WARM FRONT LIFTING THROUGH EASTERN KENTUCKY IN CONJUNCTION WITH AN AREA OF LOW PRESSURE DEVELOPING TO THE SOUTHWEST. SOME LIGHT RAIN SHOWERS HAVE BEEN ASSOCIATED WITH THIS BOUNDARY ALONG WITH PATCHES OF FOG AND LOW CIGS. TEMPERATURES ARE RATHER MILD ACROSS THE AREA WITH MID 30S FOUND NORTH OF THE FRONT AND LOW 40S TO THE SOUTH OF IT. DEWPOINTS THROUGH THE AREA ARE WITHIN A DEGREE OR TWO OF THE AIR TEMPERATURE. THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST. THEY ALL DEPICT A CLOSED LOW CURRENTLY OVER SOUTHERN NEW MEXICO BEING PICKED UP BY THE NORTHERN STREAM FLOW TODAY AND MOVING THROUGH THE OHIO VALLEY ON SUNDAY AS A FULL LATITUDE TROUGH. THE LATEST ECMWF AND NAM ARE THE MOST SIMILAR WITH THIS TRANSITION AND WERE LEANED ON MOST FOR THIS FORECAST. IN ADDITION...THE LATEST HRRR WAS INCORPORATED INTO THE NEAR TERM PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE A RATHER WARM EARLY JANUARY DAY ACROSS EASTERN KENTUCKY AS SCATTERED SHOWERS MOVE THROUGH DURING THE MORNING HOURS. AN INVERSION WILL KEEP THE GUSTY WINDS JUST OFF THE SFC FROM AFFECTING THOSE OF US AT GROUND LEVEL. HOWEVER...THIS COULD BREAK BY AFTERNOON AND BRING SOME OF THOSE GUSTY WINDS TO THE SFC. IN ADDITION...THE DEEPENING LOW TO THE WEST AND ITS WARM FRONT NORTH OF THE AREA WILL SET THE STAGE FOR A POTENTIAL OF MAINLY ELEVATED THUNDERSTORMS...THOUGH THEY COULD BECOME SFC BASED...ESPECIALLY IF THE CLOUDS THIN OR BREAK OVER THIS PART OF THE STATE LATER TODAY. THE HIGHEST POPS AND STEADIER RAINS SHOULD STAY WEST OF THE AREA FOR MUCH OF THE DAY...THOUGH IF ANY BANDS DO SET UP AHEAD OF THE COLD FRONT WE COULD SEE HEAVY TO EXCESSIVE RAINS GIVEN THE VERY HIGH PWATS FOR THIS PART OF THE YEAR. MOST LIKELY...THOUGH...THE BEST RAINS WILL STAY TO THE WEST OF THE AREA...CLOSER TO THE CORE OF THE SYSTEM...UNTIL LATER IN THE EVENING AND OVERNIGHT WHEN THE COLD FRONT LUNGES THIS WAY. WITH THIS PASSAGE...EXPECT A PERIOD OF HEAVY RAIN AND POSSIBLE THUNDERSTORMS ALONG WITH GUSTY SOUTHWEST WINDS. AT THIS POINT WILL HOLD OFF ON ANY FLOOD WATCHES GIVEN THE EXPECTATION OF DOWNSLOPING IN THE EAST AND SOME DRY SLOTTING AHEAD OF THE COLD FRONT. THE POTENTIAL FOR HEAVY RAINS TONIGHT WILL BE HIT HARD IN THE HWO ALONG WITH THE CONCERN FOR GUSTY WINDS. THE FRONT GOES THROUGH SHORTLY AFTER 12Z SUNDAY WITH FALLING TEMPERATURES EXPECTED THROUGH THE REST OF THE DAY. WOULD ALSO EXPECT SOME WRAP AROUND AND UPSLOPE PCPN TO DEVELOP IN THE FRONT/S WAKE LATER IN THE AFTERNOON. THIS...COMBINED WITH FALLING TEMPERATURES...WILL LIKELY RESULT IN SOME LIGHT SNOW SHOWERS AROUND THE AREA INTO SUNDAY EVENING. WHILE NO ACCUMULATIONS ARE EXPECTED FROM THIS...THERE COULD BE BRIEF DUSTINGS WHERE ANY HEALTHY SNOW SHOWER PASSES. WILL ADD THIS FLEETING SNOW POTENTIAL TO THE HWO...AS WELL. AGAIN USED THE BCCONSSHORT AS A STARTING POINT FOR TEMPS...TD...AND WINDS THROUGH 21Z TODAY AND THEN THE SUPERBLEND THROUGH 00Z MONDAY. ONLY SLIGHTLY TWEAKED POINT TEMPERATURE DATA FOR MAXES AND MINS. AS FOR POPS...FAVORED A BLEND OF THE HRRR AND NAM12 EARLY THEN MAINLY THE NAM12 TONIGHT INTO SUNDAY. GENERALLY UNDERCUT MOS TODAY... ESPECIALLY EAST...WENT CATEGORICAL TONIGHT...AND THEN ENDED UP HIGHER THAN MOS FOR SUNDAY AFTERNOON AND EVENING. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 340 AM EST SAT JAN 3 2015 THE UPPER LEVEL PATTERN THROUGH THE EXTENDED FORECAST PERIOD WILL FEATURE A BROAD TROUGH OVER THE GREAT LAKES AND NEW ENGLAND REGIONS WITH A SERIES OF SHORTWAVES ROUNDING THE BASE OF THE TROUGH AND MOVING THROUGH THE LOWER GREAT LAKES AND OH VALLEY REGION. TOWARDS THE END OF THE EXTENDED PORTION OF THE FORECAST ON THURSDAY AND INTO FRIDAY A STRONG JET STREAK DIVES SOUTHEAST OUT OF CENTRAL CANADA AND INTO THE LOWER TN VALLEY AS THE LONGWAVE TROUGH OVER THE EASTERN CONUS DEEPENS AND A POTENT SHORTWAVE MOVES THROUGH THE MID ATLANTIC STATES AND OFF THE ATLANTIC COAST. FOR THE MOST PART...THE MODELS AGREE WITH WITH THE OVERALL PROGRESSION OF THE LONGWAVE PATTERN. CLOSER TO THE SURFACE...A COLD FRONT WILL EXIT EASTERN KENTUCKY ON SUNDAY NIGHT WITH SOME WRAP AROUND MOISTURE...THOUGH SHALLOW...MAKING IT THROUGH EASTERN KENTUCKY. WITH THE COLDER AIR FILTERING INTO THE AREA IN EARNEST...THIS WILL RESULT INTO A CHANGE OVER TO SOME SNOW SHOWERS AND IS EXPECTED TO BE SHORT IN DURATION AS THE MOISTURE AND UPPER TROUGH WILL BE QUICK TO EXIT. DO NOT EXPECT MORE THAN A DUSTING WITH THIS ACTIVITY. COLDER AIR WILL BE WELL ENTRENCHED THROUGH THE AREA FOR MONDAY AND TUESDAY AND ESPECIALLY THROUGH THE REST OF THE EXTENDED. THE NEXT COLD FRONT WILL PUSH THROUGH THE OH VALLEY ON TUESDAY AND TUESDAY NIGHT. IN NORTHWEST FLOW...THE BEST MOISTURE AND LIFT WITH THIS FEATURE APPEARS TO BE NORTH OF THE OH RIVER AND THEREFORE LITTLE PRECIP POSSIBLE INTO EASTERN KENTUCKY. THIS THINKING IS INLINE WITH THE RESULT OF THE ALL MODEL BLEND AND AS SUCH HAVE STAYED WITH A DRY FORECAST. DID GO WITH SOME FLURRIES IN THE VERY NORTH THOUGH WITH NO MEASURABLE PRECIP EXPECTED. THIS FRONT MOVES THROUGH TUESDAY NIGHT AND QUITE AN ARCTIC AIRMASS FOLLOWS IN BEHIND THIS FEATURE. ARCTIC HIGH PRESSURE WILL MOVE SOUTHEAST INTO THE LOWER MS RIVER VALLEY AND WITH IT...SOME VERY COLD AND DRY AIR. THIS WILL KEEP EASTERN KENTUCKY DRY FOR THE REST OF THE EXTENDED FORECAST PERIOD AND BRING SOME NEAR ZERO TEMPERATURES FOR THURSDAY MORNING AND DRY AIR. DEW POINTS FOR THURSDAY WILL DROP INTO THE NEGATIVE DIGITS AND ONLY RISE INTO THE TEENS FOR FRIDAY. A COLD AND DRY TREND WILL BE IN STORE FOR THE END OF NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 100 AM EST SAT JAN 3 2015 SOUTH-SOUTHEAST FLOW AHEAD OF AN APPROACHING WARM FRONT WILL STRENGTHEN OVERNIGHT AS IT PUSHES NORTHWARD. THIS WILL YIELD SOME DOWNSLOPING FLOW OFF THE HIGHER TERRAIN ACROSS FAR EASTERN KENTUCKY. THIS SHOULD HELP KEEP CIGS A BIT HIGHER THROUGH THE NIGHT...OVER THE EASTERN PARTS OF THE FORECAST AREA. THE BEST CHANCES FOR PERIODS OF MVFR CIGS WILL BE ACROSS SOUTH-CENTRAL KENTUCKY...WHICH WILL BE LESS INFLUENCED BY THIS DOWNSLOPING FLOW. WHILE SPRINKLES AND LIGHT RAIN SHOWERS WILL BE AROUND OVERNIGHT...THE BEST RAIN CHANCES SHOULD HOLD OFF UNTIL LATER SATURDAY MORNING. ACCORDINGLY...MAINLY VFR CONDITIONS SHOULD PREVAIL FOR THE EASTERN TAF SITES. MAIN AVIATION CONCERN WILL BE DEVELOPING LLWS LATE TONIGHT AND TOMORROW AS WINDS STRENGTHEN JUST OFF THE SURFACE TO BETWEEN 40 AND 45 KNOTS. THIS WILL LIKELY PERSIST THROUGH AT LEAST THE MORNING AS THE INVERSION HOLDS TOUGH. DO EXPECT SOME MIXING OF THE GUSTS TO THE SFC SATURDAY AFTERNOON WITH SOME BREAKS IN THE SKY COVER POSSIBLE ONCE WE ARE IN THE DEVELOPING SYSTEM/S WARM SECTOR. CANNOT RULE OUT A STRAY THUNDERSTORM FOR SATURDAY AFTERNOON BUT FOR NOW HAVE LEFT THEM OUT OF THE TAFS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...SHALLENBERGER AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
335 AM EST SAT JAN 3 2015 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 335 AM EST SAT JAN 3 2015 08Z SFC ANALYSIS SHOWS A WARM FRONT LIFTING THROUGH EASTERN KENTUCKY IN CONJUNCTION WITH AN AREA OF LOW PRESSURE DEVELOPING TO THE SOUTHWEST. SOME LIGHT RAIN SHOWERS HAVE BEEN ASSOCIATED WITH THIS BOUNDARY ALONG WITH PATCHES OF FOG AND LOW CIGS. TEMPERATURES ARE RATHER MILD ACROSS THE AREA WITH MID 30S FOUND NORTH OF THE FRONT AND LOW 40S TO THE SOUTH OF IT. DEWPOINTS THROUGH THE AREA ARE WITHIN A DEGREE OR TWO OF THE AIR TEMPERATURE. THE MODELS ARE IN GOOD AGREEMENT ALOFT THROUGH THE SHORT TERM PORTION OF THE FORECAST. THEY ALL DEPICT A CLOSED LOW CURRENTLY OVER SOUTHERN NEW MEXICO BEING PICKED UP BY THE NORTHERN STREAM FLOW TODAY AND MOVING THROUGH THE OHIO VALLEY ON SUNDAY AS A FULL LATITUDE TROUGH. THE LATEST ECMWF AND NAM ARE THE MOST SIMILAR WITH THIS TRANSITION AND WERE LEANED ON MOST FOR THIS FORECAST. IN ADDITION...THE LATEST HRRR WAS INCORPORATED INTO THE NEAR TERM PORTION OF THE FORECAST. SENSIBLE WEATHER WILL FEATURE A RATHER WARM EARLY JANUARY DAY ACROSS EASTERN KENTUCKY AS SCATTERED SHOWERS MOVE THROUGH DURING THE MORNING HOURS. AN INVERSION WILL KEEP THE GUSTY WINDS JUST OFF THE SFC FROM AFFECTING THOSE OF US AT GROUND LEVEL. HOWEVER...THIS COULD BREAK BY AFTERNOON AND BRING SOME OF THOSE GUSTY WINDS TO THE SFC. IN ADDITION...THE DEEPENING LOW TO THE WEST AND ITS WARM FRONT NORTH OF THE AREA WILL SET THE STAGE FOR A POTENTIAL OF MAINLY ELEVATED THUNDERSTORMS...THOUGH THEY COULD BECOME SFC BASED...ESPECIALLY IF THE CLOUDS THIN OR BREAK OVER THIS PART OF THE STATE LATER TODAY. THE HIGHEST POPS AND STEADIER RAINS SHOULD STAY WEST OF THE AREA FOR MUCH OF THE DAY...THOUGH IF ANY BANDS DO SET UP AHEAD OF THE COLD FRONT WE COULD SEE HEAVY TO EXCESSIVE RAINS GIVEN THE VERY HIGH PWATS FOR THIS PART OF THE YEAR. MOST LIKELY...THOUGH...THE BEST RAINS WILL STAY TO THE WEST OF THE AREA...CLOSER TO THE CORE OF THE SYSTEM...UNTIL LATER IN THE EVENING AND OVERNIGHT WHEN THE COLD FRONT LUNGES THIS WAY. WITH THIS PASSAGE...EXPECT A PERIOD OF HEAVY RAIN AND POSSIBLE THUNDERSTORMS ALONG WITH GUSTY SOUTHWEST WINDS. AT THIS POINT WILL HOLD OFF ON ANY FLOOD WATCHES GIVEN THE EXPECTATION OF DOWNSLOPING IN THE EAST AND SOME DRY SLOTTING AHEAD OF THE COLD FRONT. THE POTENTIAL FOR HEAVY RAINS TONIGHT WILL BE HIT HARD IN THE HWO ALONG WITH THE CONCERN FOR GUSTY WINDS. THE FRONT GOES THROUGH SHORTLY AFTER 12Z SUNDAY WITH FALLING TEMPERATURES EXPECTED THROUGH THE REST OF THE DAY. WOULD ALSO EXPECT SOME WRAP AROUND AND UPSLOPE PCPN TO DEVELOP IN THE FRONT/S WAKE LATER IN THE AFTERNOON. THIS...COMBINED WITH FALLING TEMPERATURES...WILL LIKELY RESULT IN SOME LIGHT SNOW SHOWERS AROUND THE AREA INTO SUNDAY EVENING. WHILE NO ACCUMULATIONS ARE EXPECTED FROM THIS...THERE COULD BE BRIEF DUSTINGS WHERE ANY HEALTHY SNOW SHOWER PASSES. WILL ADD THIS FLEETING SNOW POTENTIAL TO THE HWO...AS WELL. AGAIN USED THE BCCONSSHORT AS A STARTING POINT FOR TEMPS...TD...AND WINDS THROUGH 21Z TODAY AND THEN THE SUPERBLEND THROUGH 00Z MONDAY. ONLY SLIGHTLY TWEAKED POINT TEMPERATURE DATA FOR MAXES AND MINS. AS FOR POPS...FAVORED A BLEND OF THE HRRR AND NAM12 EARLY THEN MAINLY THE NAM12 TONIGHT INTO SUNDAY. GENERALLY UNDERCUT MOS TODAY... ESPECIALLY EAST...WENT CATEGORICAL TONIGHT...AND THEN ENDED UP HIGHER THAN MOS FOR SUNDAY AFTERNOON AND EVENING. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 306 PM EST FRI JAN 2 2015 THE EXTENDED PERIOD BEGINS WARM AND WET ON SUNDAY MORNING JANUARY THE FOURTH. A LARGE SWATH OF LIGHT TO MODERATE RAIN IS PROGGED TO MOVE ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS ALONG AND JUST AHEAD OF A VERY POTENT COLD FRONT. THE RAIN IS EXPECTED TO GRADUALLY TAPER OFF FROM WEST TO EASTERN SUNDAY AND SUNDAY NIGHT AS THE FRONT MOVES THROUGH. THE PRECIPITATION SHOULD BE OUT OF THE AREA BY LATE SUNDAY NIGHT. AFTER THAT...A FRIGID ARCTIC AIR MASS IS EXPECTED TO SETTLE OVER THE REGION FOR A FEW DAYS. AFTER A MODEST COOL DOWN SUNDAY NIGHT...DURING WHICH TIME TEMPERATURES ARE EXPECTED TO DROP INTO THE 20S ACROSS THE AREA...A SECOND REINFORCING SHOT OF COLD AIR IS EXPECTED TO INVADE THE AREA TUESDAY NIGHT...AS A FAST MOVING CLIPPER SYSTEM PASSES BY JUST TO OUR NORTH. BASED ON THE LATEST MOS GUIDANCE AND MODEL SOUNDINGS...THE MERCURY COULD DROP INTO THE TEENS AND LOW 20S TUESDAY NIGHT...AND PERHAPS EVEN INTO THE SINGLE DIGITS WEDNESDAY NIGHT. THE CULPRIT OF THESE FRIGID TEMPERATURES WOULD COME IN THE FORM OF A LARGE RIDGE OF ARCTIC HIGH PRESSURE THAT IS EXPECTED TO SETTLE OVER THE EASTERN CONUS MID WEEK. AFTER SUNDAY AND SUNDAY NIGHT...THE ONLY PRECIPITATION THAT MAY AFFECT THE AREA WOULD COME TUESDAY AFTERNOON AND EVENING AS THE CLIPPER SYSTEM MOVES PAST. ANY RAIN OR SNOW THAT FALLS THAT DAY WOULD LIKELY OCCUR NORTH OF THE MOUNTAIN PARKWAY WITH LITTLE ACCUMULATION EXPECTED. THE REST OF THE WEEK IS FORECAST TO BE DRY AND QUITE COLD. HIGHS ON WEDNESDAY AND THURSDAY MAY NOT CLIMB OUT OF THE 20S. MONDAY LOOKS TO BE PRETTY COLD AS WELL...WITH HIGHS IN THE 30S ANTICIPATED ON THAT DAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 100 AM EST SAT JAN 3 2015 SOUTH-SOUTHEAST FLOW AHEAD OF AN APPROACHING WARM FRONT WILL STRENGTHEN OVERNIGHT AS IT PUSHES NORTHWARD. THIS WILL YIELD SOME DOWNSLOPING FLOW OFF THE HIGHER TERRAIN ACROSS FAR EASTERN KENTUCKY. THIS SHOULD HELP KEEP CIGS A BIT HIGHER THROUGH THE NIGHT...OVER THE EASTERN PARTS OF THE FORECAST AREA. THE BEST CHANCES FOR PERIODS OF MVFR CIGS WILL BE ACROSS SOUTH-CENTRAL KENTUCKY...WHICH WILL BE LESS INFLUENCED BY THIS DOWNSLOPING FLOW. WHILE SPRINKLES AND LIGHT RAIN SHOWERS WILL BE AROUND OVERNIGHT...THE BEST RAIN CHANCES SHOULD HOLD OFF UNTIL LATER SATURDAY MORNING. ACCORDINGLY...MAINLY VFR CONDITIONS SHOULD PREVAIL FOR THE EASTERN TAF SITES. MAIN AVIATION CONCERN WILL BE DEVELOPING LLWS LATE TONIGHT AND TOMORROW AS WINDS STRENGTHEN JUST OFF THE SURFACE TO BETWEEN 40 AND 45 KNOTS. THIS WILL LIKELY PERSIST THROUGH AT LEAST THE MORNING AS THE INVERSION HOLDS TOUGH. DO EXPECT SOME MIXING OF THE GUSTS TO THE SFC SATURDAY AFTERNOON WITH SOME BREAKS IN THE SKY COVER POSSIBLE ONCE WE ARE IN THE DEVELOPING SYSTEM/S WARM SECTOR. CANNOT RULE OUT A STRAY THUNDERSTORM FOR SATURDAY AFTERNOON BUT FOR NOW HAVE LEFT THEM OUT OF THE TAFS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...GREIF LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
303 AM EST Sat Jan 3 2015 .SHORT TERM (Now through Sunday)... Issued at 300 AM EST Sat Jan 3 2015 Latest water vapor imagery with 500 mb RAP heights shows a deep closed low across southern New Mexico while a ridge lies off the Florida coast. In between, broad southwesterly flow has been bringing a very moist and warm air mass into the Ohio Valley. At the surface, high pressure is departing the region, allowing a warm front to lift through TN and KY. Early morning temperatures range from the upper 30s across southern IN to upper 40s across southern KY. As a surface low deepens to our west, plan on the warm front to lift through Kentucky this morning and reach southern Indiana by early afternoon. As the region becomes well within the warm sector, temperatures will top out right around 60 degrees for much of the area. Southern Kentucky locations are most likely to get into the lower 60s. Southerly winds will increase throughout the day as well, as soundings show a rather strong 850 mb jet of 55+ knots at about 2-3kft. An inversion in the lowest levels of the atmosphere should keep these strong winds from mixing down, but it will still be gusty at times today. Precipitation this morning is expected to be on the lighter side, mainly in the form of drizzle or light rain showers. Precipitation chances/coverage will then steadily increase today as isentropic upglide picks up and the region becomes more in the nose of the 850mb moisture transport axis. The greatest forcing/lift arrives by mid/late afternoon through the evening hours as the cold front swings through the state. Just ahead of this front, PWATs climb to 1.6 inches, which would be record values for this time of year for BNA/ILN. Overall, a very moist air mass will be in place and though the system is expected to be progressive, any training showers will be capable of some moderate to locally heavy rainfall, especially across the southern forecast area. Plan on rainfall amounts to range from 1.5 to locally 2 inches across the area through Sunday morning. Thunder chances are still included in the forecast as MUCAPE values are progged to be around 500 J/kg this afternoon. Tonight`s low will be quite mild, held up due to lingering precipitation and southerly flow. Plan on readings to only into the mid 40s to lower 50s, warmest east of I-65. Cold air advection kicks in between midnight and sunrise Sunday, resulting in a steady drop in temperatures during the day Sunday. Morning readings in the mid 40s to near 50 are expected to fall into the mid 30s to around 40 by mid/late afternoon. At the same time, 03.00z guidance continues to show lingering wrap around moisture behind the departing low pressure system. As temperatures aloft reach -8 to -10c, there may be enough saturation left to squeeze out a few snowflakes across southern Indiana and northern Kentucky. Otherwise, Sunday afternoon will be noticeably colder especially given cloudy skies and a brisk west/northwest wind 15-20 mph, making it feel more like the middle 20s at times. .LONG TERM (Sunday night through Friday)... Issued at 257 AM EST Sat Jan 3 2015 ...Very Cold Temperatures and Wind Chills Mid-Week... Canadian high pressure crossing the region Sunday night and Monday will bring a quick shot of chilly air. Low clouds will likely hang around for much of the night Sunday night, but should clear out just in time to allow sunrise readings to drop into the 15-20 degree range. We`ll have sunshine on Monday but the mercury will only recover into the middle 20s in southern Indiana and around 30 in Kentucky. A quick moving clipper type system will zip by to our north Monday night/Tuesday. The models have trended slightly faster and farther south with this feature. Looking at atmospheric cross-sections, even in the northernmost reaches of the LMK CWA around Madison, there`s quite a bit of dry low level air Monday night, and then on Tuesday when some low level moisture does move in it`s very shallow. So, it still appears, at least for now, that measurable precipitation is unlikely with this system. Will, however, include a chance of flurries generally north of a Salem-Frankfort-Carlisle line. Also, it should be noted that the GEM brings accumulating snows to southern Indiana and northern Kentucky late Monday night. This solution is an outlier, but these types of systems can do surprising things sometimes, so it`s still something to keep an eye on. Strong Canadian high pressure will then invade Tuesday night through Thursday. A tight surface pressure gradient on the nose of the incoming high pressure Wednesday could give us some afternoon gusts around 20 mph. With temperatures reaching only into the teens in southern Indiana and the 20s in Kentucky, Wednesday will be a cold day. Then it will get worse. Lows Wednesday night, as the cold heart of the Canadian high moves in, will be in the 0 to 5 degree range. Add to that a northwest breeze around 10 mph and we could be looking at advisory level wind chills of 10 to 15 degrees below zero as the kids head out to the bus stops Thursday morning. Highs Thursday afternoon will struggle to reach 20. A cold front will sweep through the Ohio and Tennessee Valleys Thursday night/Friday. However, the Gulf of Mexico will be completely shut off by the departing mid-week high, so no precipitation is expected. && .AVIATION (06Z TAF Update)... Issued at 1225 AM EST Sat Jan 3 2015 Plan on lowering clouds through the night as batch of IFR clouds across TN lifts north through KY. Drizzle or light rain showers will persist and increase in coverage toward sunrise. Mainly IFR ceilings expected to remain in place through the day as warm front lifts into Indiana. LLWS threat at all TAF sites looks good as very strong 2kft jet increases to 55kts by late morning to early afternoon. Soundings show the inversion remaining intact for much of the day, supporting the LLWS threat into the afternoon hours. The highest coverage of showers and threat for thunderstorms comes in the mid afternoon through the evening hours associated with a cold front passage. Decided to include VCTS at BWG/SDF/LEX as there should be a line of isolated/scattered thunderstorms moving across KY. Toward the end of TAF period, precipitation coverage will decrease as winds become westerly. Weakening but still strong 850mb jet may allow higher winds to mix down post front as well, with gusts up to 30-35 mph possible. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Short Term........ZBT Long Term.........13 Aviation..........ZBT
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
125 AM EST SAT JAN 3 2015 .UPDATE... ISSUED AT 125 AM EST SAT JAN 3 2015 BASED ON CURRENT RADAR AND THE LATEST GUIDANCE FROM THE HRRR AND NAM12 HAVE ADJUSTED POPS AND WX THROUGH THE REST OF THE NIGHT. ALSO FINE TUNED T AND TD GRIDS PER THE LATEST OBS...TRENDS...AND CONSSHORT GUIDANCE THESE HAVE BEEN SENT TO THE NDFD AND WEB SERVERS. UPDATE ISSUED AT 1032 PM EST FRI JAN 2 2015 SHOWERS HAVE ATTEMPTED TO PUSH INTO SOUTHERN KENTUCKY...BUT DRY AIR SEEMS TO BE WINNING OUT AS MUCH OF THIS APPEARS TO BE WEAKENING AS IT HEADS NORTH. IN FACT...LONDON CIGS HAVE INCREASED TO 9KFT. THIS DEMONSTRATES THE ABUNDANCE OF LOW LEVEL DRY AIR IN PLACE. THUS...PLAN TO SCALE BACK POPS A BIT OVER THE NEXT FEW HOURS...BUT LEAVE SCATTERED COVERAGE IN THE SOUTHWEST AND WEST...TAPERING OFF TO ISOLATED IN THE EAST. THIS MAY STILL BE OVERDONE AS DOWNSLOPING WINDS CONTINUE TO ERODE PRECIPITATION AS IT HEADS NORTH. FORCING APPEARS TO JUST BE TOO WEAK TO OVERCOME THE DRY AIR. MODELS ARE SHOWING A BETTER SURGE OF LIFT AND MOISTURE BETWEEN 7 AND 10 AM IN THE MORNING. PERHAPS THIS MAY BE THE BEST OPPORTUNITY FOR BETTER SHOWER COVERAGE. HOWEVER...FOR NOW...OPTING TO LEAVE THE FORECAST ALONE AND ONLY TOUCH THE NEXT FEW HOURS TO ADJUST FOR THE CURRENT TRENDS. DID ADJUST WINDS UPWARDS ON THE HIGH TERRAIN IN THE SOUTHEAST LATE TONIGHT THROUGH TOMORROW AS 900MB WINDS INCREASE TO AROUND 40 KNOTS. THIS SHOULD PRODUCE SOME STRONG GUSTY WINDS ON THE HIGHER TERRAIN. WITH INVERSION HOLDING TOUGH ON SATURDAY...WINDS MAY NOT TURN ALL THAT GUSTY ELSEWHERE. HOWEVER...IF WE CAN GET SOME CLEARING...THAT WOULD CERTAINLY HELP TO MIX DOWN SOME STRONGER WINDS. UPDATE ISSUED AT 853 PM EST FRI JAN 2 2015 WHILE ONLY A FEW SPRINKLES REMAIN ACROSS THE NORTH PRESENTLY...AN AREA OF RAIN HAS DEVELOPED ACROSS CENTRAL TENNESSEE. THIS RAIN WILL BE PUSHING NORTHEAST INTO SOUTH CENTRAL KENTUCKY OVER THE NEXT FEW HOURS. HAVE ADJUSTED POPS TO TIME THIS AREA OF PRECIPITATION NORTHWARD ACROSS CENTRAL KENTUCKY. THE EASTWARD EXTENT IS STILL IN QUESTION DUE TO DRIER DOWNSLOPING FLOW (HIGHER CIG HEIGHTS)...SO WILL GO WITH AN EAST TO WEST GRADIENT IN POPS. HRRR HAS PICKED UP ON THIS FEATURE WITH THE LAST FEW RUNS AND SHOWS ANOTHER LULL AS THIS AREA PUSHES NORTH BY EARLY MORNING. HOWEVER...WILL LEAVE SOME LOW POPS IN THROUGH THE REMAINDER OF THE NIGHT AS WE COULD SEE SHOWERS POP UP AT ANY TIME GIVEN THE SATURATED ENVIRONMENT. HOWEVER...OUTSIDE OF THE RAIN PUSHING NORTHWARD NOW...IT LOOKS LIKE THE ACTIVITY THROUGH THE REMAINDER OF THE NIGHT MAY BE MORE ISOLATED. UPDATE ISSUED AT 544 PM EST FRI JAN 2 2015 UPDATED FORECAST TO LOWER POPS THROUGH THE EVENING. STILL HAVE MODEST DEWPOINT DEPRESSIONS OUT THERE. A FEW BETTER RETURNS ARE COMING OUT OF CENTRAL KENTUCKY...BUT FOR THE MOST PART THE BETTER RETURNS ARE VERY ISOLATED. IN FACT...NOT MANY STATIONS REPORTING MEASURABLE PRECIPITATION EVEN WITH THE HEAVIER RETURNS. THUS...WILL CUT DOWN POPS THROUGH 06Z. HRRR/RAP CONTINUE TO SUPPORT VERY LITTLE EVEN THROUGH THE REST OF THE NIGHT. THIS COULD BE THE CASE GIVEN THE SOUTH/SOUTHEAST WINDS WILL ONLY STRENGTHEN AS WE HEAD THROUGH THE NIGHT...KEEPING THE FLOW DOWNSLOPING INTO EASTERN KENTUCKY. HOWEVER...NOT WILLING TO GO TOO LOW QUITE YET AS BETTER JET ARRIVES TOWARDS DAYBREAK AND COULD KICK START THINGS LATE TONIGHT. HOWEVER...UNTIL THE FLOW GOES MORE SOUTH/SOUTHWEST...WE MAY NOT SEE MUCH RAIN SHOWER ACTIVITY. CERTAINLY SOMETHING TO WATCH TONIGHT. ALSO...NO SUPPORT FOR THUNDER...ESPECIALLY SINCE PRECIPITATION MAY BE LACKING TO BEGIN WITH. THUS...WILL PULL THUNDER CHANCES FROM TONIGHT INTO TOMORROW. ANY THUNDER WILL LIKELY COME WITH THE COLD FRONT TOMORROW NIGHT...BUT EVEN THERE INSTABILITY IS WEAK. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 353 PM EST FRI JAN 2 2015 HIGH PRESSURE CONTINUES TO SIT ACROSS THE FAR EASTERN PORTION OF THE CWA AND WILL CONTINUE TO DRIFT NORTHEASTWARD THROUGHOUT THE AFTERNOON/EVENING. AS IT DOES...A SURFACE LOW PRESSURE SYSTEM WILL LIFT FROM LOUISIANA AND QUICKLY NORTHEASTWARD...PULLING A QUICK MOVING WARM FRONT ACROSS THE REGION BETWEEN 12 AND 18Z TOMORROW WITH STRONG SOUTHERLY FLOW. THIS WILL PUT EASTERN KY IN THE WARM SECTOR THROUGH THE REST OF SATURDAY AFTERNOON...BEFORE THE COLD FRONT SWEEPS FROM WEST TO EAST SATURDAY NIGHT INTO SUNDAY MORNING. MVFR CLOUD COVER HAS OVERSPREAD THE REGION IN ADVANCE OF THIS SYSTEM...WITH ISL/SCT LIGHT RAIN CONTINUING TO SHOW UP OVER PORTIONS OF THE STATE. EXPECT THIS RAIN TO INTENSIFY AS WE HEAD INTO THE EVENING AND OVERNIGHT TONIGHT...AS THE WARM FRONT PUSHES NORTHWARD AND BRINGS MOISTURE FLOW IN FROM THE SOUTH. MODEL SOUNDINGS ARE STILL SHOWING A VERY IMPRESSIVE LOW LEVEL INVERSION DEVELOPING OVERNIGHT WITH A MID LEVEL WARM NOSE KEEPING PRECIP WELL ABOVE FREEZING UNDER STRONG SW FLOW. CONTINUED WITH MENTION OF THUNDER POSSIBILITIES DURING THE LATE NIGHT AND INTO THE DAY TOMORROW AS THE WARM FRONT MOVES THROUGH THE REGION. THE INCREASED LIFT WITH THE BOUNDARY...IN ADDITION TO THE WARM UNSTABLE AIR...COULD LEAD TO SOME ELEVATED CONVECTION IN THE AREA. TEMPERATURES WILL MAKE AN IMPRESSIVE JUMP INTO THE UPPER 50S TO AROUND 60 BY TOMORROW AFTERNOON UNDER THIS STRONG SOUTHERLY FLOW. IT IS POSSIBLE THAT WE MAY GET DRY SLOTTED IN THE SE TOMORROW ONCE THE WARM FRONT PASSES THROUGH...AND BEFORE THE INFLUENCE OF THE COLD FRONT...BUT KEPT IN LOWER CHANCE POPS JUST IN CASE SOME SCATTERED CONVECTION LINGERS. EXPECT THE WARMER TEMPS AND PRECIP CHANCES TO CONTINUE INTO THE OVERNIGHT HOURS TOMORROW NIGHT AS THE WARM FRONT BECOMES STALLED TO OUR NORTH AND WE AWAIT THE APPROACHING COLD FRONT...WHICH THE LATEST GFS HAS SET TO PASS THROUGH AROUND 6Z. IT IS JUST BEFORE AND DURING THE PASSAGE OF THE COLD FRONT THAT WE WILL LIKELY SEE OUR MOST WIDESPREAD POPS AND HIGHEST QPF. UP TO AN INCH OF QPF COULD FALL BETWEEN 0 AND 12Z SUNDAY...WHICH IS PRETTY CONSISTENT BETWEEN THE LAST FEW MODEL RUNS...FORECAST PACKAGES...AND BETWEEN THE NEIGHBORING OFFICES. IN ADDITION TO MORE WIDESPREAD RAIN...FORECAST SOUNDINGS ARE ALSO SHOWING HEAVIER CONVECTIVE/THUNDERSTORM POTENTIAL SATURDAY EVENING/SATURDAY NIGHT...WITH VERY STRONG LOW LEVEL WIND SHEAR AND PRESENT ON THE LATEST NAM12 AND GFS40 FORECAST SOUNDINGS...A VERY SMALL LOW LEVEL INVERSION...INCREASING LAPSE RATES...AND PWAT VALUES WELL OVER AN INCH /ALMOST AN INCH AND A HALF/. THE COLD FRONT WILL PASS THROUGH AFTER 6Z ACROSS MUCH OF THE CWA...WITH THE BEST CONVECTIVE POTENTIAL AND HEAVIEST RAINFALL PUSHING OUT WITH IT. HAVE POPS STARTING TO TAPER DOWN FROM DEFINITE TO CHANCES DURING THE LAST 6 HOURS OF THE SHORT TERM FORECAST PERIOD. FORECAST SOUNDINGS ARE SHOWING A FAST INTRUSION OF DRY AIR IN THE MID AND UPPER LEVELS...SO EXPECT PRECIP RATES TO DIMINISH QUICKLY BY DAWN. A LINGERING THUNDERSTORM WILL STILL BE A POSSIBILITY...THOUGH IT SHOULD BE IN A WEAKENING/DYING STATE. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 306 PM EST FRI JAN 2 2015 THE EXTENDED PERIOD BEGINS WARM AND WET ON SUNDAY MORNING JANUARY THE FOURTH. A LARGE SWATH OF LIGHT TO MODERATE RAIN IS PROGGED TO MOVE ACROSS THE OHIO AND TENNESSEE VALLEY REGIONS ALONG AND JUST AHEAD OF A VERY POTENT COLD FRONT. THE RAIN IS EXPECTED TO GRADUALLY TAPER OFF FROM WEST TO EASTERN SUNDAY AND SUNDAY NIGHT AS THE FRONT MOVES THROUGH. THE PRECIPITATION SHOULD BE OUT OF THE AREA BY LATE SUNDAY NIGHT. AFTER THAT...A FRIGID ARCTIC AIR MASS IS EXPECTED TO SETTLE OVER THE REGION FOR A FEW DAYS. AFTER A MODEST COOL DOWN SUNDAY NIGHT...DURING WHICH TIME TEMPERATURES ARE EXPECTED TO DROP INTO THE 20S ACROSS THE AREA...A SECOND REINFORCING SHOT OF COLD AIR IS EXPECTED TO INVADE THE AREA TUESDAY NIGHT...AS A FAST MOVING CLIPPER SYSTEM PASSES BY JUST TO OUR NORTH. BASED ON THE LATEST MOS GUIDANCE AND MODEL SOUNDINGS...THE MERCURY COULD DROP INTO THE TEENS AND LOW 20S TUESDAY NIGHT...AND PERHAPS EVEN INTO THE SINGLE DIGITS WEDNESDAY NIGHT. THE CULPRIT OF THESE FRIGID TEMPERATURES WOULD COME IN THE FORM OF A LARGE RIDGE OF ARCTIC HIGH PRESSURE THAT IS EXPECTED TO SETTLE OVER THE EASTERN CONUS MID WEEK. AFTER SUNDAY AND SUNDAY NIGHT...THE ONLY PRECIPITATION THAT MAY AFFECT THE AREA WOULD COME TUESDAY AFTERNOON AND EVENING AS THE CLIPPER SYSTEM MOVES PAST. ANY RAIN OR SNOW THAT FALLS THAT DAY WOULD LIKELY OCCUR NORTH OF THE MOUNTAIN PARKWAY WITH LITTLE ACCUMULATION EXPECTED. THE REST OF THE WEEK IS FORECAST TO BE DRY AND QUITE COLD. HIGHS ON WEDNESDAY AND THURSDAY MAY NOT CLIMB OUT OF THE 20S. MONDAY LOOKS TO BE PRETTY COLD AS WELL...WITH HIGHS IN THE 30S ANTICIPATED ON THAT DAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 100 AM EST SAT JAN 3 2015 SOUTH-SOUTHEAST FLOW AHEAD OF AN APPROACHING WARM FRONT WILL STRENGTHEN OVERNIGHT AS IT PUSHES NORTHWARD. THIS WILL YIELD SOME DOWNSLOPING FLOW OFF THE HIGHER TERRAIN ACROSS FAR EASTERN KENTUCKY. THIS SHOULD HELP KEEP CIGS A BIT HIGHER THROUGH THE NIGHT...OVER THE EASTERN PARTS OF THE FORECAST AREA. THE BEST CHANCES FOR PERIODS OF MVFR CIGS WILL BE ACROSS SOUTH-CENTRAL KENTUCKY...WHICH WILL BE LESS INFLUENCED BY THIS DOWNSLOPING FLOW. WHILE SPRINKLES AND LIGHT RAIN SHOWERS WILL BE AROUND OVERNIGHT...THE BEST RAIN CHANCES SHOULD HOLD OFF UNTIL LATER SATURDAY MORNING. ACCORDINGLY...MAINLY VFR CONDITIONS SHOULD PREVAIL FOR THE EASTERN TAF SITES. MAIN AVIATION CONCERN WILL BE DEVELOPING LLWS LATE TONIGHT AND TOMORROW AS WINDS STRENGTHEN JUST OFF THE SURFACE TO BETWEEN 40 AND 45 KNOTS. THIS WILL LIKELY PERSIST THROUGH AT LEAST THE MORNING AS THE INVERSION HOLDS TOUGH. DO EXPECT SOME MIXING OF THE GUSTS TO THE SFC SATURDAY AFTERNOON WITH SOME BREAKS IN THE SKY COVER POSSIBLE ONCE WE ARE IN THE DEVELOPING SYSTEM/S WARM SECTOR. CANNOT RULE OUT A STRAY THUNDERSTORM FOR SATURDAY AFTERNOON BUT FOR NOW HAVE LEFT THEM OUT OF THE TAFS. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GREIF SHORT TERM...JMW LONG TERM...AR AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS SHREVEPORT LA
1118 AM CST SAT JAN 3 2015 .DISCUSSION... BAND OF CONVECTION WILL CONTINUE TO GRADUALLY MOVE EWD THROUGH THE REMAINDER OF THE DAY. PRECIP WILL GENERALLY BE CONFINED EAST OF A LINE FROM TOLEDO BEND RESERVOIR...TO MINDEN LA...TO EL DORADO AR. HAVE ADJUSTED POPS BASED ON LATEST RADAR TRENDS AND REMOVED RAIN CHANCES BACK TO THE WEST. TRIMMED BACK THE FLASH FLOOD WATCH TO COINCIDE TO THE BACK EDGE OF THE CONVECTION. /09/ && .PREV DISCUSSION... /ISSUED 624 AM CST SAT JAN 3 2015/ AVIATION... FOR THE 12/03Z TAFS...WIDESPREAD SHWRS AND SOME EMBEDDED TSTMS WILL PERSIST THROUGH THE FIRST HALF OF THE TAF PERIOD FOR MOST OF OUR AREA TERMINALS...GRADUALLY ENDING FROM WEST TO EAST LATER TODAY AS A COLD FRONT SWEEPS ACROSS THE REGION. LOW CLOUDS WILL LAG BEHIND THE FRONT SO MVFR/IFR CIGS WILL LINGER THROUGH THE AFTERNOON AND POSSIBLY THE EARLY EVENING HOURS AT OUR ERN TAF SITES. VSBYS WILL ALSO REMAIN IN FLUX WITH THE RAINFALL AND RESULTING BR...GENERALLY IN THE MVFR RANGE BUT CANNOT RULE OUT SOME IFR PERIODS WITH HEAVIER RAINFALL. WINDS WILL BE MOSTLY VARIABLE AVERAGING AROUND 10 KTS WITH HIGHER GUSTS IN CONVECTION AND EXPECT VEERING TO A SW DIRECTION LATER THIS MORNING AHEAD OF THE COLD FRONT...EVENTUALLY BECOMING W AND THEN NW TOWARD THE END OF THE PERIOD AS THE FRONT ADVANCES EWRD WITH CONDITIONS IMPROVING TO VFR AROUND 04/00Z AND SHORTLY THEREAFTER AT ELD/MLU. /19/ PREV DISCUSSION... /ISSUED 549 AM CST SAT JAN 3 2015/ DISCUSSION... SORRY FOR THE LATE PRODUCTS...AS SOME OF THESE STORMS DECIDED TO GO ROGUE ON US THIS MORNING AS THE STORMS ROLLED INTO SHV/DEEP E TX/WCNTRL LA. BUT THE LEADING EDGE OF THE STORMS/GUSTY WINDS HAVE ACCELERATED E QUICKLY ACROSS NCNTRL LA AS OF 11Z...MUCH FASTER THAN THE 00Z NAM/GFS. THE HRRR HAS INITIALIZED ON THIS WELL...AS HAVE HAD TO MAKE A COUPLE OF ADDITIONAL CHANGES TO THE TEMPS TODAY AS THIS SHALLOW/COLDER AIR QUICKLY OVERTAKES THE WARM SECTOR ACROSS NCNTRL LA. EARLIER THIS MORNING AS OF 06Z...THERE WAS A SFC LOW IN VC OF LFK...BUT THIS HAS BECOME ILL-DEFINED AS THE CONVECTION ACCELERATED E...WITH WHAT LIMITED OF A SVR THREAT DIMINISHES FURTHER THIS MORNING AS THIS SFC TROUGH QUICKLY SPREADS E TOWARDS THE MS RIVER. WILL STILL HAVE TO CONTEND WITH LOCALLY HEAVY RAINFALL THIS MORNING/EARLY AFTERNOON ACROSS EXTREME ERN TX/N LA/SCNTRL AR...WHERE WIDESPREAD 3-5+ INCHES OF RAIN HAS FALLEN IN THE LAST WEEK...AND PW/S ARE FORECAST TO APPROACH NEAR RECORD VALUES FOR JANUARY /PER CLIMATOLOGY/. BELIEVE THAT THE HEAVY RAINFALL THREAT WILL DIMINISH AFTER 18Z AS THE STRONGER STORMS EXIT THE AREA...BUT WILL ALLOW THE CURRENT FLASH FLOOD WATCH TO EXPIRE AS SCHEDULED AT 22Z. SHOULD SEE THE STRATOCU LINGER THROUGH THE AFTERNOON...ALTHOUGH SOME BREAKS WILL BE POSSIBLE LATER IN THE DAY ACROSS E TX...WHICH WOULD RESULT IN A LITTLE BETTER WARMING THAN AREAS FARTHER N AND E. GIVEN THE FASTER MOVEMENT OF THE SFC TROUGH THIS MORNING...HAVE ALSO TRIMMED BACK MAX TEMPS OVER EXTREME NW LA...WITH MAX TEMPS FARTHER E ACROSS NCNTRL LA OCCURRING BY DAYBREAK WITH TEMPS FALLING DURING THE DAY. THE SHORT TERM PROGS ARE STILL IN AGREEMENT WITH OUR ARCTIC FRONT MOVING INTO THE REGION AFTER 06Z...DEEPENING LATE THROUGH SUNDAY AS A 1040MB SFC RIDGE BUILDS E ACROSS THE CNTRL/SRN PLAINS. SHOULD SEE THE FIRST FREEZE OF THE NEW YEAR MONDAY MORNING...AS THE SKY CLEARS AND WINDS DECOUPLE IN THE VERY COLD/DRY AIR MASS BUILDING IN. A SECOND ARCTIC FRONT WILL QUICKLY BUILD SE INTO THE AREA TUESDAY AHEAD OF THE NEXT LONGWAVE TO DIVE SE ACROSS THE CNTRL/ERN CONUS...WITH WHAT SHOULD BE THE COLDEST TEMPS SO FAR THIS WINTER SEASON...WITH SE OK/NRN SECTIONS OF SW AR POSSIBLY FALLING INTO THE TEENS...WITH THE REMAINDER OF THE REGION WELL INTO THE 20S. HAVE KEPT THE REMAINDER OF THE EXTENDED DRY GIVEN THE DRY NW FLOW ALOFT...ALTHOUGH THE POTENTIAL FOR -SHRA APPEARS TO INCREASE NEXT WEEKEND AS A SHORTWAVE BEGINS TO OPEN UP AND SHIFT E ACROSS THE SRN PLAINS...RESULTING IN ENHANCED OVERRUNNING AS THE ARCTIC AIR MASS BEGINS TO MODIFY. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 54 39 46 27 46 / 20 0 0 0 0 MLU 66 42 49 28 46 / 100 30 0 0 0 DEQ 51 32 40 21 41 / 10 10 0 0 0 TXK 53 37 41 23 42 / 20 10 0 0 0 ELD 57 39 46 24 43 / 100 10 0 0 0 TYR 53 34 44 25 45 / 10 0 0 0 0 GGG 53 37 44 25 45 / 10 0 0 0 0 LFK 57 37 50 27 48 / 20 0 0 0 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: ARZ073. LA...FLASH FLOOD WATCH UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: LAZ004>006-011>014-017>022. OK...NONE. TX...NONE. && $$ 09
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
624 AM CST SAT JAN 3 2015 .AVIATION... FOR THE 12/03Z TAFS...WIDESPREAD SHWRS AND SOME EMBEDDED TSTMS WILL PERSIST THROUGH THE FIRST HALF OF THE TAF PERIOD FOR MOST OF OUR AREA TERMINALS...GRADUALLY ENDING FROM WEST TO EAST LATER TODAY AS A COLD FRONT SWEEPS ACROSS THE REGION. LOW CLOUDS WILL LAG BEHIND THE FRONT SO MVFR/IFR CIGS WILL LINGER THROUGH THE AFTERNOON AND POSSIBLY THE EARLY EVENING HOURS AT OUR ERN TAF SITES. VSBYS WILL ALSO REMAIN IN FLUX WITH THE RAINFALL AND RESULTING BR...GENERALLY IN THE MVFR RANGE BUT CANNOT RULE OUT SOME IFR PERIODS WITH HEAVIER RAINFALL. WINDS WILL BE MOSTLY VARIABLE AVERAGING AROUND 10 KTS WITH HIGHER GUSTS IN CONVECTION AND EXPECT VEERING TO A SW DIRECTION LATER THIS MORNING AHEAD OF THE COLD FRONT...EVENTUALLY BECOMING W AND THEN NW TOWARD THE END OF THE PERIOD AS THE FRONT ADVANCES EWRD WITH CONDITIONS IMPROVING TO VFR AROUND 04/00Z AND SHORTLY THEREAFTER AT ELD/MLU. /19/ && .PREV DISCUSSION... /ISSUED 549 AM CST SAT JAN 3 2015/ DISCUSSION... SORRY FOR THE LATE PRODUCTS...AS SOME OF THESE STORMS DECIDED TO GO ROGUE ON US THIS MORNING AS THE STORMS ROLLED INTO SHV/DEEP E TX/WCNTRL LA. BUT THE LEADING EDGE OF THE STORMS/GUSTY WINDS HAVE ACCELERATED E QUICKLY ACROSS NCNTRL LA AS OF 11Z...MUCH FASTER THAN THE 00Z NAM/GFS. THE HRRR HAS INITIALIZED ON THIS WELL...AS HAVE HAD TO MAKE A COUPLE OF ADDITIONAL CHANGES TO THE TEMPS TODAY AS THIS SHALLOW/COLDER AIR QUICKLY OVERTAKES THE WARM SECTOR ACROSS NCNTRL LA. EARLIER THIS MORNING AS OF 06Z...THERE WAS A SFC LOW IN VC OF LFK...BUT THIS HAS BECOME ILL-DEFINED AS THE CONVECTION ACCELERATED E...WITH WHAT LIMITED OF A SVR THREAT DIMINISHES FURTHER THIS MORNING AS THIS SFC TROUGH QUICKLY SPREADS E TOWARDS THE MS RIVER. WILL STILL HAVE TO CONTEND WITH LOCALLY HEAVY RAINFALL THIS MORNING/EARLY AFTERNOON ACROSS EXTREME ERN TX/N LA/SCNTRL AR...WHERE WIDESPREAD 3-5+ INCHES OF RAIN HAS FALLEN IN THE LAST WEEK...AND PW/S ARE FORECAST TO APPROACH NEAR RECORD VALUES FOR JANUARY /PER CLIMATOLOGY/. BELIEVE THAT THE HEAVY RAINFALL THREAT WILL DIMINISH AFTER 18Z AS THE STRONGER STORMS EXIT THE AREA...BUT WILL ALLOW THE CURRENT FLASH FLOOD WATCH TO EXPIRE AS SCHEDULED AT 22Z. SHOULD SEE THE STRATOCU LINGER THROUGH THE AFTERNOON...ALTHOUGH SOME BREAKS WILL BE POSSIBLE LATER IN THE DAY ACROSS E TX...WHICH WOULD RESULT IN A LITTLE BETTER WARMING THAN AREAS FARTHER N AND E. GIVEN THE FASTER MOVEMENT OF THE SFC TROUGH THIS MORNING...HAVE ALSO TRIMMED BACK MAX TEMPS OVER EXTREME NW LA...WITH MAX TEMPS FARTHER E ACROSS NCNTRL LA OCCURRING BY DAYBREAK WITH TEMPS FALLING DURING THE DAY. THE SHORT TERM PROGS ARE STILL IN AGREEMENT WITH OUR ARCTIC FRONT MOVING INTO THE REGION AFTER 06Z...DEEPENING LATE THROUGH SUNDAY AS A 1040MB SFC RIDGE BUILDS E ACROSS THE CNTRL/SRN PLAINS. SHOULD SEE THE FIRST FREEZE OF THE NEW YEAR MONDAY MORNING...AS THE SKY CLEARS AND WINDS DECOUPLE IN THE VERY COLD/DRY AIR MASS BUILDING IN. A SECOND ARCTIC FRONT WILL QUICKLY BUILD SE INTO THE AREA TUESDAY AHEAD OF THE NEXT LONGWAVE TO DIVE SE ACROSS THE CNTRL/ERN CONUS...WITH WHAT SHOULD BE THE COLDEST TEMPS SO FAR THIS WINTER SEASON...WITH SE OK/NRN SECTIONS OF SW AR POSSIBLY FALLING INTO THE TEENS...WITH THE REMAINDER OF THE REGION WELL INTO THE 20S. HAVE KEPT THE REMAINDER OF THE EXTENDED DRY GIVEN THE DRY NW FLOW ALOFT...ALTHOUGH THE POTENTIAL FOR -SHRA APPEARS TO INCREASE NEXT WEEKEND AS A SHORTWAVE BEGINS TO OPEN UP AND SHIFT E ACROSS THE SRN PLAINS...RESULTING IN ENHANCED OVERRUNNING AS THE ARCTIC AIR MASS BEGINS TO MODIFY. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 54 39 46 27 46 / 100 0 0 0 0 MLU 66 42 49 28 46 / 100 20 0 0 0 DEQ 51 32 40 21 41 / 70 10 0 0 0 TXK 53 37 41 23 42 / 90 10 0 0 0 ELD 57 39 46 24 43 / 100 10 0 0 0 TYR 53 34 44 25 45 / 50 0 0 0 0 GGG 53 37 44 25 45 / 90 0 0 0 0 LFK 57 37 50 27 48 / 100 0 0 0 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: ARZ072-073. LA...FLASH FLOOD WATCH UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: LAZ001>006-010>014-017>022. OK...NONE. TX...FLASH FLOOD WATCH UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ151>153-165>167. && $$ 19
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
549 AM CST SAT JAN 3 2015 .DISCUSSION... SORRY FOR THE LATE PRODUCTS...AS SOME OF THESE STORMS DECIDED TO GO ROGUE ON US THIS MORNING AS THE STORMS ROLLED INTO SHV/DEEP E TX/WCNTRL LA. BUT THE LEADING EDGE OF THE STORMS/GUSTY WINDS HAVE ACCELERATED E QUICKLY ACROSS NCNTRL LA AS OF 11Z...MUCH FASTER THAN THE 00Z NAM/GFS. THE HRRR HAS INITIALIZED ON THIS WELL...AS HAVE HAD TO MAKE A COUPLE OF ADDITIONAL CHANGES TO THE TEMPS TODAY AS THIS SHALLOW/COLDER AIR QUICKLY OVERTAKES THE WARM SECTOR ACROSS NCNTRL LA. EARLIER THIS MORNING AS OF 06Z...THERE WAS A SFC LOW IN VC OF LFK...BUT THIS HAS BECOME ILL-DEFINED AS THE CONVECTION ACCELERATED E...WITH WHAT LIMITED OF A SVR THREAT DIMINISHES FURTHER THIS MORNING AS THIS SFC TROUGH QUICKLY SPREADS E TOWARDS THE MS RIVER. WILL STILL HAVE TO CONTEND WITH LOCALLY HEAVY RAINFALL THIS MORNING/EARLY AFTERNOON ACROSS EXTREME ERN TX/N LA/SCNTRL AR...WHERE WIDESPREAD 3-5+ INCHES OF RAIN HAS FALLEN IN THE LAST WEEK...AND PW/S ARE FORECAST TO APPROACH NEAR RECORD VALUES FOR JANUARY /PER CLIMATOLOGY/. BELIEVE THAT THE HEAVY RAINFALL THREAT WILL DIMINISH AFTER 18Z AS THE STRONGER STORMS EXIT THE AREA...BUT WILL ALLOW THE CURRENT FLASH FLOOD WATCH TO EXPIRE AS SCHEDULED AT 22Z. SHOULD SEE THE STRATOCU LINGER THROUGH THE AFTERNOON...ALTHOUGH SOME BREAKS WILL BE POSSIBLE LATER IN THE DAY ACROSS E TX...WHICH WOULD RESULT IN A LITTLE BETTER WARMING THAN AREAS FARTHER N AND E. GIVEN THE FASTER MOVEMENT OF THE SFC TROUGH THIS MORNING...HAVE ALSO TRIMMED BACK MAX TEMPS OVER EXTREME NW LA...WITH MAX TEMPS FARTHER E ACROSS NCNTRL LA OCCURRING BY DAYBREAK WITH TEMPS FALLING DURING THE DAY. THE SHORT TERM PROGS ARE STILL IN AGREEMENT WITH OUR ARCTIC FRONT MOVING INTO THE REGION AFTER 06Z...DEEPENING LATE THROUGH SUNDAY AS A 1040MB SFC RIDGE BUILDS E ACROSS THE CNTRL/SRN PLAINS. SHOULD SEE THE FIRST FREEZE OF THE NEW YEAR MONDAY MORNING...AS THE SKY CLEARS AND WINDS DECOUPLE IN THE VERY COLD/DRY AIR MASS BUILDING IN. A SECOND ARCTIC FRONT WILL QUICKLY BUILD SE INTO THE AREA TUESDAY AHEAD OF THE NEXT LONGWAVE TO DIVE SE ACROSS THE CNTRL/ERN CONUS...WITH WHAT SHOULD BE THE COLDEST TEMPS SO FAR THIS WINTER SEASON...WITH SE OK/NRN SECTIONS OF SW AR POSSIBLY FALLING INTO THE TEENS...WITH THE REMAINDER OF THE REGION WELL INTO THE 20S. HAVE KEPT THE REMAINDER OF THE EXTENDED DRY GIVEN THE DRY NW FLOW ALOFT...ALTHOUGH THE POTENTIAL FOR -SHRA APPEARS TO INCREASE NEXT WEEKEND AS A SHORTWAVE BEGINS TO OPEN UP AND SHIFT E ACROSS THE SRN PLAINS...RESULTING IN ENHANCED OVERRUNNING AS THE ARCTIC AIR MASS BEGINS TO MODIFY. PRELIMS TO FOLLOW BELOW... 15 && .PRELIMINARY POINT TEMPS/POPS... SHV 54 39 46 27 46 / 100 0 0 0 0 MLU 66 42 49 28 46 / 100 20 0 0 0 DEQ 51 32 40 21 41 / 70 5 0 0 0 TXK 53 37 41 23 42 / 90 5 0 0 0 ELD 57 39 46 24 43 / 100 10 0 0 0 TYR 53 34 44 25 45 / 50 0 0 0 0 GGG 53 37 44 25 45 / 90 0 0 0 0 LFK 57 37 50 27 48 / 100 0 0 0 0 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...FLASH FLOOD WATCH UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: ARZ072-073. LA...FLASH FLOOD WATCH UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: LAZ001>006-010>014-017>022. OK...NONE. TX...FLASH FLOOD WATCH UNTIL 4 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ151>153-165>167. && $$ 15
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
118 AM EST SAT JAN 3 2015 .SYNOPSIS... A STORM SYSTEM WILL BRING A BRIEF WINTRY MIX EARLY SATURDAY FOLLOWED BY RAIN THROUGH SATURDAY NIGHT. && .NEAR TERM /THROUGH TODAY/... OVERNIGHT UPDATE TO ADJUST POPS AND PRECIP TYPE BASED ON LATEST RADAR TRENDS. WILL ISSUE AN SPS FOR COUNTIES OUTSIDE OF ADVISORIES FOR A BRIEF PERIOD OF FREEZING RAIN AT THE ONSET OF PRECIP THIS MORNING. NO OTHER CHANGES. NO WHOLE-SALE CHANGES MADE TO THE OVERALL FORECAST AS PROGRESSION OF THE SYSTEM AND FZRA THREAT REMAINS ON TRACK. SOME OF THE NOTEWORTHY UPDATES INCLUDE CUTTING BACK ON SKY IN THE VERY NEAR TERM AS THE THICKER CLOUD COVER TO OUR SOUTH HAS STALLED OVER WV...LEAVING ONLY THIN HIGH CLOUDS STREAMING THROUGH THE FORECAST AREA. LESS CLOUDS HAS RESULTED IN A GENERAL LOWERING OF INITIAL TEMPS NOW THROUGH ABOUT 06Z AS THE THIN VEIL OF HIGH CLOUDS HAS NOT BEEN ENOUGH TO QUELL THE ONSET OF RADIATIONAL COOLING. TEMPS ARE DOWN A FEW DEGREES ACROSS THE BOARD FROM EARLIER PROJECTIONS...HOWEVER BACKING WINDS OVER THE NEXT SEVERAL HOURS WILL BEGIN TO RAPIDLY ADVANCE THE CLOUDS AND WARMER LLVL TEMPS INTO OUR CWA. THE WARM FRONT WILL SPREAD PRECIPITATION FROM S TO N ACROSS THE FORECAST AREA TONIGHT FOCUSED PRIMARILY ACROSS THE HIGHER ELEVATIONS OF THE SE FIRST AND THEN ALONG A STRONGER WAVE THROUGH ERN OH/WRN PA BY SAT MORNING. LOCAL HI-RES MODEL AND HRRR HAVE PRETTY GOOD HANDLE ON SFC TEMPS THROUGH MID-MORNING SAT...HIGHLIGHTING BOTH THE WARMING WEST OF THE RIDGES WITH THE DOWNSLOPING AND THE COLD AIR DAMMED UP AGAINST THE ERN SLOPES OF THE RIDGES. BLENDED PREVIOUS FORECAST THAT SIDED HEAVILY TOWARDS NAM TEMPS WITH THESE HI-RES OPTIONS...WHILE MAKING THE NECESSARY TERRAIN ALTERATIONS NECESSARY FOR THE ERLY LLVL FLOW SET UP. AGAIN...THIS GENERALLY KEEPS THE PREVIOUS FORECAST GOING...BUT PROVIDES A FEW TWEAKS TRIMMING BACK FZRA POTENTIAL FROM PIT TO JUST WEST OF THE RIDGES. ALSO HELD IN THE FZRA A LITTLE LONGER BETWEEN THE LAUREL AND CHESTNUT RIDGES AND ERN GARRETT COUNTY MARYLAND TO ACCOUNT FOR POOR SCOURING OF THE COLD AIR. A FEW MORE HOURS WITH FZRA COULD MEAN PORTIONS OF GARRETT CO. COULD PUSH CLOSE TO THE 1/4" ICE THRESHOLD REQUIRING AN ICE STORM WARNING...BUT MOST GUIDANCE KEEPS THE HIGHER AMOUNTS OF QPF MUCH CLOSER TO THE SFC LOW TRACKING THROUGH OHIO. DRIER AIR IN THE WARM SECTOR OF THE SYSTEM COULD LIMIT OVERALL OUTPUT OVER THE HIGH TERRAIN. WITH FAIRLY LOW CONFIDENCE OF EXCEEDANCE...WILL HOLD STEADY WITH CURRENT ADVISORIES. TAX && .SHORT TERM /TONIGHT THROUGH 6 PM SUNDAY/... THE BULK OF THE RAINFALL WILL HAVE MOVED EAST OF THE FORECAST AREA BY SUNDAY MORNING AS A COLD FRONT CROSSES THE REGION. CHANCES FOR RAIN WILL DIMINISH THROUGH THE MORNING...WITH A BRIEF LULL IN PRECIPITATION SUNDAY AFTERNOON BEFORE THE NEXT WAVE APPROACHES FROM THE WEST. THE DIURNAL TEMPERATURE CYCLE WILL CONTINUE TO BE OFFSET...WITH TEMPERATURES FALLING THROUGH THE DAY ON SUNDAY. WINDS WILL ALSO PICK UP BEHIND THE FRONT...WITH GUSTS OVER 25 MPH AND GUSTING UP TO 35-40 MPH IN THE HIGHEST ELEVATIONS. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... MUCH COLDER SUNDAY NIGHT AND MONDAY AS 850MB TEMPS WILL RANGE FROM -16C TO -20C BY LATE DAY MONDAY WITH SCATTERED SNOW SHOWERS MAINLY RIDGES AND I-80 CORRIDOR. LOW INVERSION HEIGHTS AND WESTERLY FLOW WILL LIMIT ANY ACCUMULATIONS. INDIVIDUAL DISTURBANCES ARE PROGGED TO ADVN THRU THE BASE OF PERSISTENT ERN CONUS TROFG THRU THE PD WITH PERIODIC CHCS FOR SNW SHWRS. THE STRONGEST WAVE IS PROGGED FOR A TUE PASSAGE. TEMPS ARND 10 DEG BLO AVG ARE EXPD TO START...WITH READINGS 15 TO 20 DEG BLO AVG AFT THE TUE SHRTWV PASSAGE. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS THROUGH MUCH OF THE NIGHT BEFORE QUICKLY DROPPING TO MVFR THEN IFR FROM SOUTHWEST TO NORTHEAST AS DAWN APPROACHES. SURFACE TEMPS WILL BE THE MOST CRITICAL PART OF FORECAST EARLY ON. IT WILL BE A RACE BETWEEN THE WARMER AIR AND THE INCOMING RAIN. THINK MOST SITES WILL START AS AN HOUR OR TWO OF FZRA. THIS WILL TRANSITION TO PLAIN RA DURING THE MORNING EXCEPT AT THE NORTHERN SITES...KFKL AND KDUJ WILL BE LAST TO FULLY TRANSITION TO RAIN...NOT UNTIL SOMETIME IN THE AFTERNOON. IFR RESTRICTIONS LOOK LIKELY... THROUGH THE REMAINDER OF THE PERIOD. OUTLOOK.../SATURDAY THROUGH WEDNESDAY/... WDSPRD RSTRNS AND OCNL LLWS ARE EXPD WITH WKEND LOW PRES. RSTRNS ARE ALSO PSBL WITH A SERIES OF DISTURBANCES ERLY NXT WK. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...FREEZING RAIN ADVISORY FROM 5 AM EARLY THIS MORNING TO 7 PM EST THIS EVENING FOR MDZ001. OH...NONE. PA...FREEZING RAIN ADVISORY FROM 5 AM EARLY THIS MORNING TO 2 PM EST THIS AFTERNOON FOR PAZ007>009-013>016-022-023-074-076. WV...FREEZING RAIN ADVISORY FROM 5 AM EARLY THIS MORNING TO 2 PM EST THIS AFTERNOON FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
427 PM EST SAT JAN 3 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 335 PM EST SAT JAN 3 2015 UPPER MICHIGAN IS CURRENTLY BETWEEN THE STRONGER AND PRECIPITATION PRODUCING SURFACE/UPPER LEVEL FEATURES. THE REMNANTS OF THE SURFACE LOW THAT MOVED THROUGH MINNESOTA LAST NIGHT HAS LEFT A SURFACE TROUGH OVER WESTERN LAKE SUPERIOR THIS AFTERNOON. ON THE NORTHWEST SIDE OF THAT TROUGH...SNOW HAS BEEN FALLING FOR MUCH OF THE DAY IN THE MINNESOTA ARROWHEAD IN ASSOCIATION WITH THE MID LEVEL Q-VECTOR CONVERGENCE AND THE RIGHT REAR OF THE SPLIT NORTHERN STREAM JET STREAK. FARTHER SOUTH...WATER VAPOR IMAGERY SHOWS A STRONG UPPER WAVE LIFTING NORTHEAST OUT OF THE SOUTHERN PLAINS...WHILE A SECOND WEAKER WAVE IS NEARING IT FROM THE NORTHWEST IN COLORADO. BETWEEN THESE TWO FEATURES AND BEHIND THE SHORTWAVE THAT MOVED THROUGH SOUTHEAST UPPER MICHIGAN LAST NIGHT AND THIS MORNING (PRODUCING 1-1.5IN OF SNOW NEAR LAKE MICHIGAN)...CLOUDY SKIES PREVAIL OVER UPPER MICHIGAN. THIS IS DUE TO THE LINGERING LOW LEVEL MOISTURE TRAPPED BELOW THE DRYING ALOFT BEHIND THE SHORTWAVE. ONCE THE DEEPER MOISTURE DEPARTED WITH THE SHORTWAVE...SAW A TRANSITION TO BR AND REDUCED VISIBILITIES ON THE AUTOMATED STATIONS. CALLING AROUND TO THE SOUTHERN PART OF THE CWA HAS SHOWN A TRANSITION FROM WEST TO EAST ALONG THE WISCONSIN BORDER TO FREEZING DRIZZLE OVER THE LAST COUPLE OF HOURS. FARTHER NORTH AT OUR OFFICE...WE HAVE BEEN JUST SEEING A FEW FLURRIES DUE TO CLOUD LAYER BEING RIGHT AT THE EDGE OF THE MORE FAVORABLE ICE CRYSTAL REGION. EXPECT THIS BORDERLINE/LIMITED CONDITION TO CONTINUE OVER THE SOUTH CENTRAL AND SOUTHEASTERN CWA INTO THE EVENING HOURS AND WILL SHOW THE POTENTIAL FOR FREEZING DRIZZLE IN THE FORECAST. WILL ISSUE AN SPS TO HIGHLIGHT THE FREEZING DRIZZLE AND UNTREATED ROADS BECOMING SLIPPERY FOR THE AREAS NOT CURRENTLY COVERED BY THE ADVISORY. OTHERWISE...EXPECT THE FREEZING DRIZZLE TO DIMINISH FROM WEST TO EAST THIS EVENING AS THE DEEPER MOISTURE FROM THE FEATURE OVER WESTERN LAKE SUPERIOR MOVES OVER THE U.P. TONIGHT. THE STRONG TROUGH IN THE SOUTHERN PLAINS WILL LIFT NORTHEAST THROUGH THE LOWER GREAT LAKES REGION TONIGHT...STRENGTHENING A LOW FROM 1007MB OVER SOUTHERN ILLINOIS TO 998MB BETWEEN LAKE ERIE/ONTARIO AT 12Z SUNDAY. AS THAT OCCURS...THE MID LEVEL TROUGH ASSOCIATED WITH THE SURFACE TROUGH OVER THE WESTERN LAKE WILL DROP SOUTHEAST ACROSS UPPER MICHIGAN THROUGH SUNDAY MORNING. THE SYNOPTIC LIQUID EQUIVALENT PRECIPITATION (TIED TO THE 850-650MB FGEN) LOOKS TO BE IN THE 0.10-0.15 INCH RANGE FOR MOST OF THE CWA THROUGH SUNDAY MORNING. SNOW RATIOS INITIALLY WILL LIKELY BE AROUND 10-15 TO 1 AS THERE IS STILL A PERIOD OF THE CLOUD BEING ABOVE/BELOW THE DGZ. BUT THERE WILL LIKELY BE A TRANSITION TO A BRIEF (2-4HR) PERIOD LATE TONIGHT INTO SUNDAY MORNING WHEN THE LOWEST 10-12KFT OF THE ATMOSPHERE IS WITHIN THE DGZ. THIS WOULD LEAD TO A PERIOD OF FLUFFIER SNOW AND RATIOS RISING TOWARDS OR EVEN ABOVE 20-1. DON/T FEEL COMFORTABLE GOING MUCH ABOVE THAT DUE TO THE FORCING THAT IS EXPECTED ABOVE THE DGZ. THUS...SYNOPTIC SNOW WOULD AMOUNT TO 1 TO 2.5-3.0 INCHES...WITH THE GREATEST OVER THE WEST HALF. BUT AS IS NORMALLY THE CASE WITH LAKE SUPERIOR AND OUR TERRAIN INFLUENCES...THAT ISN/T THE COMPLETE STORY ON THE SNOWFALL. MUCH COLDER AIR WILL SURGE INTO THE AREA TONIGHT BEHIND THE 850-700MB TROUGH...WITH 850MB TEMPS FALLING FROM 19Z RAP ANALYZED OF -5C TO -7C TO -19C EAST AND -24C WEST BY 18Z SUNDAY. THIS WILL LEAD TO LAKE ENHANCEMENT DEVELOPING FROM WEST TO EAST TONIGHT AND THEN TRANSITIONING TO PURE LAKE EFFECT AS THE DEEPER MOISTURE DEPARTS ON SUNDAY. THE HELP FROM THE LAKE WILL BE FOCUSED IN THE NORTHERLY WIND LOCATIONS OF THE WEST AND NORTH CENTRAL TONIGHT AND THEN WINDS BACK TO THE NORTHWEST SUNDAY MORNING AND WEST-NORTHWEST BY SUNDAY EVENING. WITH THAT COLD AIR SURGING IN...THE CLOUD LAYER ON SUNDAY WILL TRANSITION TO BEING ABOVE THE DGZ. THUS...WOULD EXPECT A TRANSITION OF THE SNOWFLAKES TO COLUMNS/PLATES AND LOWER SNOW RATIOS BELOW 20-1. CONTINUED THE TREND TOWARDS THE HIGH RESOLUTION MODELS FOR QPF AMOUNTS TONIGHT/SUNDAY IN THE LAKE/TERRAIN ENHANCED AREAS (0.25-0.40 IN). THIS LEADS TO SNOWFALL AMOUNTS OF 3-5 INCHES OF SNOW TONIGHT OVER THE FAVORED NORTH WIND AREAS OVER THE WEST AND NORTH CENTRAL. THERE COULD BE SOME LOCALIZED HIGHER AMOUNTS TOWARDS 5.5-6.0 INCHES. THE LOWERING RATIOS ON SUNDAY WILL LEAD TO LOWER AMOUNTS OVER THE WEST...BUT COULD STILL SEE 2-5 INCHES IN THE FAVORED NORTHWEST WINDS AREAS OVER THE EAST. IN ADDITION TO THE SNOW...WINDS WILL QUICKLY INCREASE FROM NORTHWEST TO SOUTHEAST TONIGHT...WITH GUSTS BETWEEN 30 TO 45 MPH (HIGHEST NEAR LAKE SUPERIOR). THAT WILL LEAD TO BLOWING SNOW AND COMBINED WITH THE EXPECTED SNOW...SHOULD SEE VISIBILITIES FREQUENTLY REDUCED BELOW ONE MILE OVER THE NORTHERN HALF OF THE CWA. THUS...THINK THE GOING ADVISORY LOOKS GOOD WITH THE FORECASTED SNOWFALL AMOUNTS AND IMPACT WITH THE REDUCED VISIBILITIES FROM BLOWING SNOW. AS MENTIONED ABOVE...THINK SOME HIGHER TERRAIN LOCATIONS FLIRTING WITH 12HR WARNING SNOWFALL AMOUNTS (DUE TO THE OVERALL AVERAGE SNOW RATIO BEING JUST BELOW OUR LAKE EFFECT WARNING CRITERIA). BUT WITH MUCH OF THE SNOW FALLING ON A WEEKEND OVERNIGHT AND THE EXPECTED COVERAGE FAIRLY LOCALIZED...WILL KEEP THE ADVISORY IN PLACE. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 426 PM EST SAT JAN 3 2015 TROUGHING AND WELL BELOW NORMAL TEMPERATURES DOMINATES THE WEATHER PATTERN FOR THE FIRST FULL WEEK OF 2015 OVER NORTH AMERICA. STILL INDICTIONS THAT A TRANSITION TO ZONAL FLOW AND ABOVE NORMAL TEMPS DEVELOPS BY MID MONTH. ECMWF INDICATES THIS PATTERN SWITCH MAY OCCUR AS EARLY AS NEXT WEEKEND WHILE GFS IS A BIT SLOWER. WOULD TEND TO THINK IT MAY TAKE LONGER GIVEN THE DEGREE OF COLD AIR OVER THE REGION AS LATE AS FRIDAY. EITHER WAY THIS UPCOMING WEEK WILL BE A VERY COLD ONE WITH SUBZERO HIGHS ON SOME DAYS AND DANGEROUSLY LOW WIND CHILLS. PATTERN DOES NOT HOLD MUCH OPPORTUNITY FOR WIDESPREAD SNOW...BUT MAINLY LAKE EFFECT SNOW FOR AREAS NEAR LK SUPERIOR FAVORED BY NORTHWEST OR WEST WINDS. LES IN NW FLOW AREAS NEAR LAKE SUPERIOR WILL BE ONGOING SUNDAY NIGHT IN WAKE OF THE LOW PRESSURE SYSTEM MOVING OVER THE CNTRL GREAT LAKES ON SUNDAY. THOUGH MAIN SHORTWAVE AND SFC TROUGH WILL BE EAST OF THE AREA...MULTIPLE SMALLER SHORTWAVES MAY PROVIDE SLIGHT ENHANCEMENT TO LES. OVER-WATER INSTABILITY EASILY EXTREME WITH H85 TEMPS DOWN TO -26C TO -28C AND 950MB TEMPS -22C TO -27C. LK SUPERIOR TEMPS STILL +2C TO 3C. INVERSION HEIGHTS TOP OUT AT THE END OF THE FETCH OVER EASTERN LK SUPERIOR 6-7KFT. DUE TO SUCH COLD AIR THE SLR/S WILL BE WELL BLO 20:1 AS SNOWFLAKES WITHIN CONVECTIVE LAYER WILL BE PLATES AND COLUMNS INSTEAD OF DENDRITES. RESULT IS A SNOW THAT WILL NOT ADD UP MUCH IN TERMS OF ACCUMULATIONS...BUT WILL BE GOOD AT REDUCING VISIBILITY. BASED ON 925MB WINDS...STEADIER LES EXPECTED SUNDAY NIGHT AND MONDAY OVER THE KEWEENAW PENINSULA AND FOR THE SNOW BELTS EAST OF MARQUETTE. POSSIBLE THAT ADDITIONAL ADVISORIES OR EXTENSION OF CURRENT WINTER WEATHER ADVISORIES FOR LES WITH LOW VSBY AND GUSTY WINDS MAY BE NEEDED INTO MONDAY...BUT WILL LET LATER SHIFTS EVALUATE THIS ONCE WE GET THROUGH THE CURRENT ADVISORIES POSTED INTO SUNDAY. OTHER THAN THE LES...THE COLD AND DANGEROUS WIND CHILLS WILL BE THE MAIN STORY OVER THE CWA TO START THE WEEK. SFC RIDGE AXIS OVER THE NORTHERN TO CENTRAL PLAINS AND LAKE INDUCED TROUGH WILL LEAD TO MODEST PRESSURE GRADIENT OVER UPR MICHIGAN SUNDAY NIGHT INTO MONDAY MORNING...BUT THERE IS NOT MUCH OF A LOW-LEVEL WIND MAX OVERHEAD AT THAT TIME. EVEN SO...IT WILL NOT TAKE MUCH WIND TO PRODUCE NEAR WARNING WIND CHILLS AS SFC TEMPS ARE EXPECTED TO BE -15F OR EVEN -20F OVER FAR SW UPR MICHIGAN. STRONGER WINDS OF 10-15 MPH MAY BE CLOSER TO LAKE INDUCED TROUGHING ALONG SOUTH SHORE OF LK SUPERIOR WHERE TEMPS SHOULD BE MORE IN THE SINGLE DIGITS BLO ZERO. WIND CHILL ADVISORIES WILL BE NEEDED FOR WEST HALF OF UPR MICHIGAN SUNDAY NIGHT AND MONDAY...WITH POSSIBLE WARNINGS OVER FAR SW UPR MICHIGAN. COORD WITH DLH AND GRB AND ISSUED A WIND CHILL WATCH FOR AREAS OF SW UPR MICHIGAN /GOGEBIC...IRON...DICKINSON/ WHERE WARNING CRITERIA OF -35F HAS BEST CHANCE OF OCCURRING. LATER IN THE DAY ON MONDAY...A CLIPPER SHORTWAVE DIVING SE OUT OF BRITISH COLUMBIA AND ALBERTA WILL SPREAD SNOW OVER THE NORTHERN PLAINS AND EVENTUALLY THIS SNOW WILL MAKE IT TO THE WESTERN GREAT LAKES ON MONDAY NIGHT. ATTM IT APPEARS THAT BULK OF THIS SYSTEM WILL MISS UPR MICHIGAN. BY MONDAY AFTN AND MONDAY EVENING THOUGH...WINDS BACKING WSW-SW AHEAD OF MORE NORTHERN STREAM SHORTWAVE AND COLD FRONT DIVING SOUTHWARD OVER MANITOBA SHOULD PUSH THE LES OVER FAR NORTHERN KEWEENAW AND OFFSHORE FM THE SNOW BELTS EAST OF MARQUETTE. DOES NOT APPEAR WINDS BACK ENOUGH ON LK MICHIGAN TO BRING LES OFF LK MICHIGAN INTO PLAY FOR SE CWA. LES STAYS MAINLY IN THE W FLOW AREAS ON MONDAY NIGHT...BUT AS THE SHORTWAVE/COLD FRONT ARRIVE ON TUESDAY WILL PUSH BACK TO NW FLOW AREAS NEAR LK SUPERIOR. SOUNDINGS SHOW SHORTWAVE AND FRONT HAS MORE OF AN AFFECT ON THE LES AS INVERSIONS RISE UP TO 10 KFT AS MORE COLD AIR WITH H85 TEMPS DOWN BLO -26C SLIDES OVER THE UPPER GREAT LAKES. LIKE MONDAY...ALL OF CONVECTIVE DEPTH IS AT TEMPS LOWER THAN DGZ...SO SMALL FLAKE SIZE AND LOW SLR/S. NW WINDS IN MIXED LAYER NEAR 30 KTS...SO BLSN MORE OF AN ISSUE THAN MONDAY. OVERALL THE POOR VSBY WILL CONINUE TO BE MAIN HAZARD FM THE LES. AIR TEMPS MAY NOT BE QUITE AS COLD AS MONDAY MORNING BUT COLD FRONT AND PRESSURE GRADIENT LOOKS MORE ROBUST. LIKELY LOOKING AT ANOTHER ROUND OF WIND CHILL ADVISORIES FOR WEST HALF OF CWA LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. PROBABLY SHOULD STAY AWAY FM ANY WARNING CRITERIA THOUGH. COLD FRONT MOVES ON THROUGH WEDNESDAY AND 1045-1050MB HIGH PRESSURE RIDGE OVER NORTHERN PLAINS PUSHES TO SOUTHERN PLAINS AND OHIO VALLEY. IN RESPONSE...BLYR WINDS BACK MORE WNW-W BY WEDNESDAY EVENING SO THE LES WILL IN TURN SHIFT AROUND AND NOT STAY PUT IN ANY ONE PLACE TOO LONG. BEST CHANCE FOR MODERATE ACCUMS AND PERSISTENT LOW VSBY WILL BE AT THE END OF THE FETCH IN THE SNOW BELTS TO EAST OF MARQUETTE. ANOTHER COLD FRONT WILL DROP ACROSS UPPER LAKES ON THURSDAY. YET ANOTHER SURGE OF H85 TEMPS BLO -25C WILL DESCEND ON THE AREA. AHEAD OF THE COLD FRONT FOR THURSDAY...WEST WINDS MAY BE STIFF LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. THE STRONGER WINDS ALONG WITH TEMPS LESS THAN 10 BLO WILL PROBABLY RESULT IN MORE WIND CHILL ADVISORIES FOR MOST OF THE WEST HALF ON THURSDAY MORNING. PROBABLY ARE GETTING THE THEME BY NOW. THIS WEEK LOOKS QUITE BRUTAL IN TERMS OF THE PROLONGED DURATION OF BITTER COLD AND WIND CHILL ISSUES. THIS WILL MAKE THE THAW EXPECTED FOR MID JANUARY FEEL ALL THE MORE BETTER. NW FLOW LES TO CLOSE THE WEEK AND INTO NEXT SATURDAY. THE NW WINDS WILL RESULT IN MORE LAKE MODERATION SO TEMPS WILL BE PROBABLY BE WARM ENOUGH TO LIMIT THE NEED OF ANY MORE WIND CHILL HEADLINES ON FRIDAY MORNING OR SATURDAY MORNING. COULD SEE SWATH OF LGT SNOW SWEEP OVER THE REGION NEXT WEEKEND AS THE WARM AIR BEGINS TO PUSH OVER THE REGION ATOP OF SLOWLY RETREATING COLD AIR NEAR SFC. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1250 PM EST SAT JAN 3 2015 UPPER MICHIGAN IS BETWEEN FEATURES AT THIS TIME...WITH VFR CONDITIONS AT KIWD/KCMX AND IFR CEILINGS AND SOME FOG/SNOW/DRIZZLE AT KSAW. THESE CONDITIONS WILL STAY FAIRLY STEADY STATE OVER THE NEXT COUPLE-FEW HOURS...THEN WILL SEE CONDITIONS DETERIORATING FROM WEST TO EAST THIS EVENING AS THE AREA OF SNOW IN THE MINNESOTA ARROWHEAD MOVES INTO THE AREA. WITH ALL THREE TAF SITES HELPED BY UPSLOPE WINDS AND LAKE ENHANCEMENT...BROUGHT THEIR VISIBILITIES BELOW ALT LANDING MINS DURING THE OVERNIGHT HOURS WHEN THE STRONGEST SNOW WILL BE MOVING THROUGH. GUSTY WINDS WILL ALSO CREATE BLOWING SNOW OVERNIGHT INTO SUNDAY...WHICH COULD LEAD TO A TRANSITION TO VERTICAL VISIBILITIES UNDER 500FT AT TIMES. THE WIDESPREAD SNOW WILL DEPART LATE TONIGHT INTO EARLY SUNDAY MORNING...LEAVING LAKE ENHANCED/EFFECT SNOW AT ALL THREE SITES SUNDAY MORNING UNDER NORTHWEST WINDS. KEPT VISIBILITIES DOWN DURING THAT PERIOD DUE TO THE SMALLER SNOW FLAKES BEING EFFICIENT REDUCERS OF VISIBILITY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 335 PM EST SAT JAN 3 2015 THE BUSY MARINE WEATHER WE HAVE HAD RECENTLY WILL CONTINUE WITH GALES AND HEAVY FREEZING SPRAY RETURNING AND HOISTED GALE WARNINGS AND HEAVY FREEZING SPRAY WARNINGS FOR LATE TONIGHT INTO SUNDAY. A COUPLE MORE GALE EVENTS ARE POSSIBLE ON LAKE SUPERIOR TUESDAY NIGHT AND WEDNESDAY MORNING AND AGAIN FOR THURSDAY NIGHT WITH NORTHWEST GALES EXPECTED THEN. FREEZING SPRAY WILL ALSO BE A PROBLEM THROUGH MOST OF THIS FORECAST PERIOD. WINDS SHIFT TO THE NORTH LATE TONIGHT AS THE NORTHERN PLAINS TROUGH MERGES WITH ANOTHER LOW PRESSURE SYSTEM LIFTING NORTH OVER THE CENTRAL GREAT LAKES. NORTH GALES TO 35-40 KTS ARE EXPECTED SUNDAY ESPECIALLY OVER THE EASTERN HALF OF LK SUPERIOR. HEAVY FREEZING SPRAY WILL DEVELOP TONIGHT AS ARCTIC AIR POURS OVER LK SUPERIOR. GALES SHOULD DIMINISH BY LATE SUNDAY NIGHT...BUT NW-W WINDS TO 30 KTS AND HEAVY FREEZING SPRAY WILL LINGER THROUGH MONDAY. W-SW WINDS TO 25 KTS ON TUESDAY AS A CLIPPER SYSTEM CROSSES UPPER GREAT LAKES. BEHIND THE CLIPPER...PLAN ON ANOTHER ROUND OF NW GALES AND HEAVY FREEZING SPRAY THROUGH WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 7 PM EST /6 PM CST/ SUNDAY FOR MIZ001>003-009-084. WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST SUNDAY FOR MIZ006- 007-085. LAKESHORE FLOOD ADVISORY FROM 1 AM TO 1 PM EST SUNDAY FOR MIZ001>003. WIND CHILL WATCH FROM SUNDAY EVENING THROUGH MONDAY MORNING FOR MIZ009>011. LAKESHORE FLOOD ADVISORY FROM 7 AM TO 7 PM EST SUNDAY FOR MIZ005>007. WINTER WEATHER ADVISORY FROM 1 AM TO 7 PM EST SUNDAY FOR MIZ004- 005. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM SUNDAY TO 1 AM EST FRIDAY FOR LSZ251-267. GALE WARNING FROM 4 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ249>251- 267. HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 1 AM EST FRIDAY FOR LSZ249-250-266. GALE WARNING FROM 1 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ266. HEAVY FREEZING SPRAY WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 1 AM EST /MIDNIGHT CST/ FRIDAY FOR LSZ162- 240>248-263>265. GALE WARNING FROM 9 PM EST /8 PM CST/ THIS EVENING TO 7 AM EST /6 AM CST/ MONDAY FOR LSZ240>248-263>265. LAKE MICHIGAN... GALE WARNING FROM 7 AM TO 7 PM EST SUNDAY FOR LMZ221-248-250. && $$ SHORT TERM...SRF LONG TERM...JLA AVIATION...SRF MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
335 PM EST SAT JAN 3 2015 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 335 PM EST SAT JAN 3 2015 UPPER MICHIGAN IS CURRENTLY BETWEEN THE STRONGER AND PRECIPITATION PRODUCING SURFACE/UPPER LEVEL FEATURES. THE REMNANTS OF THE SURFACE LOW THAT MOVED THROUGH MINNESOTA LAST NIGHT HAS LEFT A SURFACE TROUGH OVER WESTERN LAKE SUPERIOR THIS AFTERNOON. ON THE NORTHWEST SIDE OF THAT TROUGH...SNOW HAS BEEN FALLING FOR MUCH OF THE DAY IN THE MINNESOTA ARROWHEAD IN ASSOCIATION WITH THE MID LEVEL Q-VECTOR CONVERGENCE AND THE RIGHT REAR OF THE SPLIT NORTHERN STREAM JET STREAK. FARTHER SOUTH...WATER VAPOR IMAGERY SHOWS A STRONG UPPER WAVE LIFTING NORTHEAST OUT OF THE SOUTHERN PLAINS...WHILE A SECOND WEAKER WAVE IS NEARING IT FROM THE NORTHWEST IN COLORADO. BETWEEN THESE TWO FEATURES AND BEHIND THE SHORTWAVE THAT MOVED THROUGH SOUTHEAST UPPER MICHIGAN LAST NIGHT AND THIS MORNING (PRODUCING 1-1.5IN OF SNOW NEAR LAKE MICHIGAN)...CLOUDY SKIES PREVAIL OVER UPPER MICHIGAN. THIS IS DUE TO THE LINGERING LOW LEVEL MOISTURE TRAPPED BELOW THE DRYING ALOFT BEHIND THE SHORTWAVE. ONCE THE DEEPER MOISTURE DEPARTED WITH THE SHORTWAVE...SAW A TRANSITION TO BR AND REDUCED VISIBILITIES ON THE AUTOMATED STATIONS. CALLING AROUND TO THE SOUTHERN PART OF THE CWA HAS SHOWN A TRANSITION FROM WEST TO EAST ALONG THE WISCONSIN BORDER TO FREEZING DRIZZLE OVER THE LAST COUPLE OF HOURS. FARTHER NORTH AT OUR OFFICE...WE HAVE BEEN JUST SEEING A FEW FLURRIES DUE TO CLOUD LAYER BEING RIGHT AT THE EDGE OF THE MORE FAVORABLE ICE CRYSTAL REGION. EXPECT THIS BORDERLINE/LIMITED CONDITION TO CONTINUE OVER THE SOUTH CENTRAL AND SOUTHEASTERN CWA INTO THE EVENING HOURS AND WILL SHOW THE POTENTIAL FOR FREEZING DRIZZLE IN THE FORECAST. WILL ISSUE AN SPS TO HIGHLIGHT THE FREEZING DRIZZLE AND UNTREATED ROADS BECOMING SLIPPERY FOR THE AREAS NOT CURRENTLY COVERED BY THE ADVISORY. OTHERWISE...EXPECT THE FREEZING DRIZZLE TO DIMINISH FROM WEST TO EAST THIS EVENING AS THE DEEPER MOISTURE FROM THE FEATURE OVER WESTERN LAKE SUPERIOR MOVES OVER THE U.P. TONIGHT. THE STRONG TROUGH IN THE SOUTHERN PLAINS WILL LIFT NORTHEAST THROUGH THE LOWER GREAT LAKES REGION TONIGHT...STRENGTHENING A LOW FROM 1007MB OVER SOUTHERN ILLINOIS TO 998MB BETWEEN LAKE ERIE/ONTARIO AT 12Z SUNDAY. AS THAT OCCURS...THE MID LEVEL TROUGH ASSOCIATED WITH THE SURFACE TROUGH OVER THE WESTERN LAKE WILL DROP SOUTHEAST ACROSS UPPER MICHIGAN THROUGH SUNDAY MORNING. THE SYNOPTIC LIQUID EQUIVALENT PRECIPITATION (TIED TO THE 850-650MB FGEN) LOOKS TO BE IN THE 0.10-0.15 INCH RANGE FOR MOST OF THE CWA THROUGH SUNDAY MORNING. SNOW RATIOS INITIALLY WILL LIKELY BE AROUND 10-15 TO 1 AS THERE IS STILL A PERIOD OF THE CLOUD BEING ABOVE/BELOW THE DGZ. BUT THERE WILL LIKELY BE A TRANSITION TO A BRIEF (2-4HR) PERIOD LATE TONIGHT INTO SUNDAY MORNING WHEN THE LOWEST 10-12KFT OF THE ATMOSPHERE IS WITHIN THE DGZ. THIS WOULD LEAD TO A PERIOD OF FLUFFIER SNOW AND RATIOS RISING TOWARDS OR EVEN ABOVE 20-1. DON/T FEEL COMFORTABLE GOING MUCH ABOVE THAT DUE TO THE FORCING THAT IS EXPECTED ABOVE THE DGZ. THUS...SYNOPTIC SNOW WOULD AMOUNT TO 1 TO 2.5-3.0 INCHES...WITH THE GREATEST OVER THE WEST HALF. BUT AS IS NORMALLY THE CASE WITH LAKE SUPERIOR AND OUR TERRAIN INFLUENCES...THAT ISN/T THE COMPLETE STORY ON THE SNOWFALL. MUCH COLDER AIR WILL SURGE INTO THE AREA TONIGHT BEHIND THE 850-700MB TROUGH...WITH 850MB TEMPS FALLING FROM 19Z RAP ANALYZED OF -5C TO -7C TO -19C EAST AND -24C WEST BY 18Z SUNDAY. THIS WILL LEAD TO LAKE ENHANCEMENT DEVELOPING FROM WEST TO EAST TONIGHT AND THEN TRANSITIONING TO PURE LAKE EFFECT AS THE DEEPER MOISTURE DEPARTS ON SUNDAY. THE HELP FROM THE LAKE WILL BE FOCUSED IN THE NORTHERLY WIND LOCATIONS OF THE WEST AND NORTH CENTRAL TONIGHT AND THEN WINDS BACK TO THE NORTHWEST SUNDAY MORNING AND WEST-NORTHWEST BY SUNDAY EVENING. WITH THAT COLD AIR SURGING IN...THE CLOUD LAYER ON SUNDAY WILL TRANSITION TO BEING ABOVE THE DGZ. THUS...WOULD EXPECT A TRANSITION OF THE SNOWFLAKES TO COLUMNS/PLATES AND LOWER SNOW RATIOS BELOW 20-1. CONTINUED THE TREND TOWARDS THE HIGH RESOLUTION MODELS FOR QPF AMOUNTS TONIGHT/SUNDAY IN THE LAKE/TERRAIN ENHANCED AREAS (0.25-0.40 IN). THIS LEADS TO SNOWFALL AMOUNTS OF 3-5 INCHES OF SNOW TONIGHT OVER THE FAVORED NORTH WIND AREAS OVER THE WEST AND NORTH CENTRAL. THERE COULD BE SOME LOCALIZED HIGHER AMOUNTS TOWARDS 5.5-6.0 INCHES. THE LOWERING RATIOS ON SUNDAY WILL LEAD TO LOWER AMOUNTS OVER THE WEST...BUT COULD STILL SEE 2-5 INCHES IN THE FAVORED NORTHWEST WINDS AREAS OVER THE EAST. IN ADDITION TO THE SNOW...WINDS WILL QUICKLY INCREASE FROM NORTHWEST TO SOUTHEAST TONIGHT...WITH GUSTS BETWEEN 30 TO 45 MPH (HIGHEST NEAR LAKE SUPERIOR). THAT WILL LEAD TO BLOWING SNOW AND COMBINED WITH THE EXPECTED SNOW...SHOULD SEE VISIBILITIES FREQUENTLY REDUCED BELOW ONE MILE OVER THE NORTHERN HALF OF THE CWA. THUS...THINK THE GOING ADVISORY LOOKS GOOD WITH THE FORECASTED SNOWFALL AMOUNTS AND IMPACT WITH THE REDUCED VISIBILITIES FROM BLOWING SNOW. AS MENTIONED ABOVE...THINK SOME HIGHER TERRAIN LOCATIONS FLIRTING WITH 12HR WARNING SNOWFALL AMOUNTS (DUE TO THE OVERALL AVERAGE SNOW RATIO BEING JUST BELOW OUR LAKE EFFECT WARNING CRITERIA). BUT WITH MUCH OF THE SNOW FALLING ON A WEEKEND OVERNIGHT AND THE EXPECTED COVERAGE FAIRLY LOCALIZED...WILL KEEP THE ADVISORY IN PLACE. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 541 AM EST SAT JAN 3 2015 NAM SHOWS THE UPPER PATTERN CONSISTS OF A 500 MB TROUGH OVER THE CENTRAL U.S. 12Z SUN WITH SEVERAL SHORTWAVES EMBEDDED IN THIS TROUGH. THE TROUGH DIGS INTO THE UPPER GREAT LAKES ON SUNDAY AND REMAINS OVER THE AREA INTO TUE. COLD AIR MOVES INTO THE AREA ON SUNDAY AND REMAINS THROUGH MON NIGHT IN THIS FORECAST PERIOD. ACTIVE FORECAST PERIOD WITH WIND CHILL PROBLEMS...BLOWING SNOW AND LOW VISIBILITIES...HIGH WAVES AND COLD TEMPERATURES. WITH THE HIGHER WINDS AND BLOWING SNOW...DECIDED TO CONTINUE THE ADVISORIES INTO SUNDAY FOR THIS EVEN THOUGH THE HEAVIEST SNOW IS DONE. TEMPERATURES WILL CONTINUE TO FALL ALL DAY SUNDAY AND USED A NON DIURNAL CURVE WITH FALLING TEMPERATURES ALL DAY. IT DOES GET COLD ENOUGH AND HIGH ENOUGH WIND SPEEDS FOR SUNDAY NIGHT INTO MONDAY MORNING TO WORRY ABOUT WIND CHILLS AND AT SOME POINT WILL HAVE TO THINK ABOUT GOING WITH A WIND CHILL WATCH...BUT DO NOT WANT TO HAVE WINTER WEATHER ADVISORIES OUT AND THEN A WIND CHILL WATCH WHICH WOULD BE IN THE FOURTH FORECAST PERIOD FOR NOW. WILL MENTION LOW WIND CHILLS IN THE HWO PRODUCT AND NOT HAVE DOUBLE HEADLINES RIGHT NOW. WITH HIGHER WINDS ON THE WATER...LAKESHORE FLOODING BECOMES A PROBLEM AND WILL HAVE TO GO WITH A LAKESHORE FLOOD ADVISORY FOR PARTS OF THE AREA ALONG LAKE SUPERIOR FROM LATE TONIGHT INTO SUNDAY NIGHT. OTHER THAN THE HEADLINES OR POTENTIAL HEADLINES...DID NOT MAKE TOO MANY DRASTIC CHANGES TO THE GOING FORECAST FOR TEMPERATURES...POPS OR WEATHER. IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB TROUGH OVER THE U.S. WITH VERY COLD AIR ENTRENCHED OVER MOST OF THE COUNTRY 12Z TUE. AN ALBERTA CLIPPER SYSTEM MOVES TO THE SOUTH OF THE AREA ON TUE AND BRINGS A REINFORCING AND COLDER SHOT OF AIR INTO THE UPPER GREAT LAKES 12Z WED WITH 850 MB TEMPERATURES DROPPING FROM -19C OVER LAKE SUPERIOR ON TUE TO -30C 12Z WED AS STRONG HIGH PRESSURE BUILDS INTO THE PLAINS. THE CORE OF THE COLD AIR MOVES EAST INTO NEW ENGLAND 12Z THU WITH ANOTHER SHOT OF COLD AIR COMING IN FOR FRI WITH ANOTHER CLIPPER SYSTEM MOVING THROUGH THU NIGHT. TEMPERATURES WILL CONTINUE TO BE WELL BELOW NORMAL THIS FORECAST PERIOD WITH LAKE EFFECT SNOW CONTINUING. WENT WITH HIGHER POPS IN THE EXTENDED FOR LAKE EFFECT SNOWBELTS AFFECTED BY NORTHWEST WINDS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1250 PM EST SAT JAN 3 2015 UPPER MICHIGAN IS BETWEEN FEATURES AT THIS TIME...WITH VFR CONDITIONS AT KIWD/KCMX AND IFR CEILINGS AND SOME FOG/SNOW/DRIZZLE AT KSAW. THESE CONDITIONS WILL STAY FAIRLY STEADY STATE OVER THE NEXT COUPLE-FEW HOURS...THEN WILL SEE CONDITIONS DETERIORATING FROM WEST TO EAST THIS EVENING AS THE AREA OF SNOW IN THE MINNESOTA ARROWHEAD MOVES INTO THE AREA. WITH ALL THREE TAF SITES HELPED BY UPSLOPE WINDS AND LAKE ENHANCEMENT...BROUGHT THEIR VISIBILITIES BELOW ALT LANDING MINS DURING THE OVERNIGHT HOURS WHEN THE STRONGEST SNOW WILL BE MOVING THROUGH. GUSTY WINDS WILL ALSO CREATE BLOWING SNOW OVERNIGHT INTO SUNDAY...WHICH COULD LEAD TO A TRANSITION TO VERTICAL VISIBILITIES UNDER 500FT AT TIMES. THE WIDESPREAD SNOW WILL DEPART LATE TONIGHT INTO EARLY SUNDAY MORNING...LEAVING LAKE ENHANCED/EFFECT SNOW AT ALL THREE SITES SUNDAY MORNING UNDER NORTHWEST WINDS. KEPT VISIBILITIES DOWN DURING THAT PERIOD DUE TO THE SMALLER SNOW FLAKES BEING EFFICIENT REDUCERS OF VISIBILITY. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 335 PM EST SAT JAN 3 2015 THE BUSY MARINE WEATHER WE HAVE HAD RECENTLY WILL CONTINUE WITH GALES AND HEAVY FREEZING SPRAY RETURNING AND HOISTED GALE WARNINGS AND HEAVY FREEZING SPRAY WARNINGS FOR LATE TONIGHT INTO SUNDAY. A COUPLE MORE GALE EVENTS ARE POSSIBLE ON LAKE SUPERIOR TUESDAY NIGHT AND WEDNESDAY MORNING AND AGAIN FOR THURSDAY NIGHT WITH NORTHWEST GALES EXPECTED THEN. FREEZING SPRAY WILL ALSO BE A PROBLEM THROUGH MOST OF THIS FORECAST PERIOD. WINDS SHIFT TO THE NORTH LATE TONIGHT AS THE NORTHERN PLAINS TROUGH MERGES WITH ANOTHER LOW PRESSURE SYSTEM LIFTING NORTH OVER THE CENTRAL GREAT LAKES. NORTH GALES TO 35-40 KTS ARE EXPECTED SUNDAY ESPECIALLY OVER THE EASTERN HALF OF LK SUPERIOR. HEAVY FREEZING SPRAY WILL DEVELOP TONIGHT AS ARCTIC AIR POURS OVER LK SUPERIOR. GALES SHOULD DIMINISH BY LATE SUNDAY NIGHT...BUT NW-W WINDS TO 30 KTS AND HEAVY FREEZING SPRAY WILL LINGER THROUGH MONDAY. W-SW WINDS TO 25 KTS ON TUESDAY AS A CLIPPER SYSTEM CROSSES UPPER GREAT LAKES. BEHIND THE CLIPPER...PLAN ON ANOTHER ROUND OF NW GALES AND HEAVY FREEZING SPRAY THROUGH WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 7 PM EST /6 PM CST/ THIS EVENING TO 7 PM EST /6 PM CST/ SUNDAY FOR MIZ001>003-009-084. WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST SUNDAY FOR MIZ006- 007-085. LAKESHORE FLOOD ADVISORY FROM 1 AM TO 1 PM EST SUNDAY FOR MIZ001>003. LAKESHORE FLOOD ADVISORY FROM 7 AM TO 7 PM EST SUNDAY FOR MIZ005>007. WINTER WEATHER ADVISORY FROM 1 AM TO 7 PM EST SUNDAY FOR MIZ004- 005. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 7 PM SUNDAY TO 7 PM EST TUESDAY FOR LSZ251-267. GALE WARNING FROM 4 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ249>251- 267. HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 PM EST TUESDAY FOR LSZ249-250-266. GALE WARNING FROM 1 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ266. HEAVY FREEZING SPRAY WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 1 AM EST /MIDNIGHT CST/ TUESDAY FOR LSZ240>248- 263>265. GALE WARNING FROM 9 PM THIS EVENING TO 7 AM EST MONDAY FOR LSZ242>245-248-263>265. HEAVY FREEZING SPRAY WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 1 PM EST /NOON CST/ MONDAY FOR LSZ162. LAKE MICHIGAN... GALE WARNING FROM 7 AM TO 7 PM EST SUNDAY FOR LMZ221-248-250. && $$ SHORT TERM...SRF LONG TERM...07 AVIATION...SRF MARINE...SRF
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1144 PM EST FRI JAN 2 2015 .AVIATION... THE STORM SYSTEM LIFTING INTO THE REGION SATURDAY WILL CAUSE PRECIPITATION TO LIFT FROM SOUTHWEST TO NORTHEAST ACROSS SE MI DURING THE DAY...BEGINNING AROUND OR SHORTLY AFTER 12Z. THE PRECIP IS EXPECTED TO START AS SNOW AND SLEET...THEN TRANSITION TO FREEZING RAIN...THEN RAIN AS THE THERMAL PROFILES WARM. THERE IS STILL SOME UNCERTAINTY WITH RESPECT TO THE TIMING OF THESE PRECIP TYPE CHANGES ATTM. SO THERE IS LIKELY TO BE ADJUSTMENTS IN THE CHANGE OVER TIMES DURING LATER FORECAST ISSUANCES. FOR DTW...THE LATEST GUIDANCE STILL SUGGESTS PRECIP WILL BEGIN AT METRO AROUND 12Z. EXPECT CONDITIONS TO WARM ENOUGH TO SUPPORT ALL RAIN BY EARLY AFTERNOON. A LIGHT GLAZING OF ICE IS EXPECTED TO OCCUR DURING AT LEAST THE MORNING HOURS ON SATURDAY. //DTW THRESHOLD PROBABILITIES... * HIGH CONFIDENCE IN PRECIPITATION STARTING OUT FROZEN (SNOW/SLEET/FREEZING RAIN) SAT MORNING...CHANGING TO RAIN BY EARLY AFTERNOON. * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FT AFTER 12Z SAT. && .PREV DISCUSSION...ISSUED 914 PM EST FRI JAN 2 2015 UPDATE... SATELLITE DATA IS SHOWING THE MOISTURE FLUX INTO THE LOWER OHIO VALLEY WELL UNDERWAY WITHIN THE STREAM OF ISENTROPIC ASCENT TIED TO THE ENTRANCE REGION OF AN UPPER JET MAX EXTENDING ACROSS LOWER MI. THE WATER VAPOR LOOP ALSO SHOWS A MID LEVEL SHORT WAVE OVER ERN NEBRASKA. THIS LEAD WAVE IS FORECAST TO DAMPEN AS IT LIFTS INTO NRN LOWER MI SAT MORNING...SUSTAINING THE UPPER JET MAX OVER LOWER MI. THE PERSISTENT ISENTROPIC UPGLIDE INTO SRN MI WILL PULL THE DEEPER MOISTURE INTO THE AREA SAT MORNING. THE 18Z MODEL GUIDANCE AND LATEST RAP SUGGEST PRECIP WILL OVERSPREAD THE FORECAST AREA FROM THE SOUTH AND WEST BETWEEN 11Z AND 14Z. DESPITE THE THICK CIRRUS DECK NOW COVERING SRN MI...TEMPS HAVE MANAGED TO DROP OFF INTO THE MID AND UPPER 20S. DEWPOINTS HOWEVER ARE STILL IN THE UPPER TEENS AND LOW 20S ACROSS SRN MI AND NRN IN/NRN OH. IN LIGHT OF THE WET BULB COOLING...A PERIOD OF FROZEN PRECIP STILL LOOKS LIKELY PRIOR TO THE CHANGE OVER TO RAIN SAT AFTERNOON. 18Z MODEL SOUNDINGS SUGGEST PRECIP WILL BE ALL SNOW AT THE ONSET /EVEN IN METRO DETROIT/ GIVEN THE WET BULB COOLING...WITH A TRANSITIONS TO SLEET...FREEZING RAIN AND RAIN DURING THE COURSE OF THE DAY AS THE ELEVATED WARM LAYER EXPANDS NORTHWARD. OUTSIDE OF ADDING A BRIEF PERIOD OF SNOW SOUTH OF M 59 SAT MORNING...THE CURRENT FORECAST AND WINTER WEATHER ADVISORY IN EFFECT FOR SATURDAY WILL REMAIN UNCHANGED. PREV DISCUSSION...ISSUED 358 PM EST FRI JAN 2 2015 SHORT TERM...TONIGHT ENOUGH SUNSHINE THIS AFTERNOON HELPED BOOST TEMPERATURES ABOVE THE FREEZING MARK ACROSS THE MAJORITY OF SOUTHEAST MICHIGAN. HOWEVER...WITH DEW PTS IN THE TEENS...WE ARE SET UP FOR A QUICK FALL THIS EVENING AS WINDS GO CALM/LIGHT UNDER PARTLY CLOUDY SKIES/HIGH CLOUDS. A GOOD SURGE OF MOISTURE/WARM ADVECTION WILL TAKE PLACE OVERNIGHT AS SHORTWAVE OVER NEBRASKA LIFTS INTO THE WESTERN GREAT LAKES. CLOUDS WILL QUICKLY THICKEN UP OVERNIGHT...AND WITH SURFACE WINDS PICKING UP OUT OF THE SOUTHEAST...TEMPERATURES SHOULD BEGIN TO SLOWLY RISE TOWARD SUNRISE. GOOD CHANCE THE BEST RADIATORS/THUMB REGION SLIPPING INTO THE UPPER TEENS WITH PREDOMINATELY LOWER 20S ELSEWHERE BEFORE TEMPS BEGIN THE UPWARD CLIMB. SHOULD REMAIN DRY IN THE TONIGHT PERIOD...AS 12Z NAM INDICATING 285 K SATURATION OVER SOUTHWEST LOWER MICHIGAN...WITH CONDENSATION PRESSURE DEFICIT STILL AROUND 100 MB THROUGH 12Z SATURDAY OVER MUCH OF SOUTHEAST MICHIGAN...EXCEPT ACROSS THE FAR SOUTHWEST WHERE WE WILL INCLUDE LOW CHANCE POPS FOR A WINTRY MIX OF PRECIPITATION. LONG TERM... SATURDAY THROUGH FRIDAY A WINTER WEATHER ADVISORY IS IN EFFECT SATURDAY WITH INCREASED CONFIDENCE ON A PERIOD OF MIXED PRECIPITATION OVER SE MICHIGAN. EXPECT MOSTLY FREEZING RAIN WITH NEAR A TENTH INCH OF ICING FROM THE OHIO BORDER UP TO THE NORTHERN SUBURBS OF DETROIT WHERE THE M-59 CORRIDOR WILL START A GREATER MIX WITH SNOW AT THE ONSET. IT WILL BE ALL SNOW IN FLINT...THE TRI CITIES AND NORTHERN THUMB TO START BEFORE A TRANSITION TO SLEET AND FREEZING RAIN BY AFTERNOON. A GENERAL 1 TO 3 INCH SNOW ACCUMULATION IS EXPECTED BUT WITH A SUBSTANTIAL COMPONENT OF SLEET AND ABOUT A TENTH INCH OF ICING LIKELY BEFORE SURFACE TEMPERATURE RISES ABOVE FREEZING ALL LOCATIONS DURING MID TO LATE AFTERNOON. A KEY FACTOR IN OBSERVATIONS TODAY IS JUST HIGH CLOUDS OVERHEAD AFTER DISSIPATION OF THE SURFACE FRONT. THIS WILL GIVE TEMPERATURES A HEAD START DOWN INTO THE 20S TONIGHT FOR A STARTING POINT SATURDAY AS AND PRECIPITATION MOVES IN FROM THE SOUTH TOWARD SUNRISE. SURFACE PRESSURE FALLS OVER THE UPPER MIDWEST... ASSOCIATED WITH THE NORTHERN STREAM UPPER LEVEL TROUGH...COMBINED WITH THE DEVELOPING LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS... WILL RESULT IN MODERATE SOUTHEAST WIND OVER LOWER MICHIGAN. THIS IS NOT SUPPORTIVE OF A CONTINUOUS RESUPPLY OF LOW LEVEL COLD AIR BUT ALSO IS NOT IDEAL FOR A RAPID SCOURING OF THE SHALLOW SUB FREEZING BOUNDARY LAYER AIR THAT WILL BE IN PLACE OVER SE MICHIGAN. PRECIPITATION RATE EARLY IN THE EVENT WILL ALSO BE MORE LIKELY TO COOL THE SURFACE LAYER THROUGH WET BULB PROCESSES BEFORE THE MAIN SURGE OF PRECIPITATION ARRIVES DURING THE AFTERNOON AND REALLY MOISTENS UP AND WARMS CONDITIONS ABOVE FREEZING FROM SOUTH TO NORTH OVER THE REGION. THE 12Z MODEL PACKAGE IS IN REASONABLE AGREEMENT ON THE EVOLUTION OF THE LARGER SCALE FEATURES COMING TOGETHER OVER THE GREAT LAKES FOR THIS EVENT. THE INITIAL ROUND OF FORCING FOR PRECIPITATION WILL BE ASSOCIATED WITH MID LEVEL WARM ADVECTION/ISENTROPIC LIFT ASSOCIATED WITH LONG WAVE HEIGHT RISES DOWNSTREAM OF THE WAVE DIGGING INTO THE CENTRAL ROCKIES TONIGHT. THIS APPEARS SOLID IN SATELLITE IMAGERY WITH THE ADDED BONUS OF THE COMPACT AND INTENSE CIRCULATION EMBEDDED WITHIN THE SOUTHERN STREAM WHICH WILL LEAD THE FOUR CORNERS SYSTEM OUT OF THE SOUTHERN PLAINS. THE LEAD WAVE WILL ADD A LAYER OF DYNAMIC FORCING TO GO ALONG WITH THE GENERAL PATTERN OF DEEP THETA-E ADVECTION. AT THE SAME TIME...SURFACE LOW DEVELOPMENT OVER THE NORTHERN PLAINS AND UPPER MIDWEST WILL AUGMENT LOW LEVEL WARM ADVECTION FORCED BY THE LARGER SCALE DOWNSTREAM RIDGE DEVELOPMENT. MODEL SOLUTIONS THEN INDICATE BULK THICKNESS AND LOW LEVEL TEMPERATURE FIELDS WARMING QUICKLY FROM SOUTH TO NORTH OVER LOWER MICHIGAN LEAVING ONLY THE TRI CITIES NEAR THE RAIN/SNOW LINE BY AFTERNOON. MODEL SOUNDINGS INDICATE ENOUGH MID LEVEL WARMING FOR A RAPID TRANSITION THROUGH FROZEN TO LIQUID PRECIPITATION TYPES TO SUCH AN EXTENT THAT THE DETROIT METRO AREA MAY NOT SEE ANY SNOW EARLY IN THE EVENT. THE INITIAL MOISTURE SURGE WILL THEN RELOAD WITH THE SOUTHERN PLAINS UPPER LOW. PRECIPITATION TYPE WILL THEN CHANGE TO ALL RAIN AS RATES INCREASE WITH THIS FEATURE. THE TRI CITIES WILL REMAIN CLOSEST TO THE RAIN/SNOW LINE PUSHED FARTHER INTO NORTHERN/WESTERN LOWER BY THEN. MUCH COLDER AIR AND STRONG WIND WILL THEN BECOME THE MAIN STORY BY SUNDAY AS THE LOW PRESSURE SYSTEM EXITS THE REGION. LIGHT ACCUMULATION OF SNOW IS LIKELY UNDER THE MID LEVEL DEFORMATION PATTERN...WHICH IS STILL SUBJECT TO SOME POSITIONAL ADJUSTMENT IN UPCOMING MODEL RUNS...BUT CURRENTLY FAVORS AN INCH OR TWO OF ADDITIONAL SNOW ACCUMULATION MAINLY IN THE TRI CITIES TO NORTHERN THUMB REGION. THE FIRST CONCERN IN THE EXTENDED PERIOD WILL BE A PERIOD OF COLD ARCTIC AIR FILTERING IN TO THE REGION IN THE BEGINNING OF NEXT WEEK. BEHIND THE DEPARTING LOW PRESSURE SYSTEM VERY COLD AIR WILL STREAM INTO THE GREAT LAKES REGION RESULTING IN HIGHS ON MONDAY BARELY RISING OUT OF THE SINGLE DIGITS /15 FOR DETROIT METRO...ONLY 11 FOR MOST OF THE REST OF THE CWA/. LOWS ON MONDAY NIGHT WILL DROP INTO THE MIDDLE SINGLE DIGITS WITH WIND CHILL VALUES IN THE NEGATIVE SINGLE DIGITS. TUESDAYS HIGHS WILL BE SLIGHTLY WARMER IN THE UPPER TEENS AND LOW 20S. THE SECOND CONCERN FOR THE EXTENDED PERIOD WILL BE THE CHANCE OF A CLIPPER SYSTEM TO IMPACT THE CENTRAL GREAT LAKES ON TUESDAY AND TUESDAY NIGHT. MODELS ARE FAIRLY CONSISTENT ON THIS FEATURE HOWEVER...INCONSISTENT WITH THE TIMING AND INTENSITY. THEREFORE IT IS TOO EARLY TO TRY TO PINPOINT SNOWFALL TOTALS AT THIS TIME. MARINE... WINDS BECOMING LIGHT THIS EVENING WILL SHIFT TO THE SOUTHEAST OVERNIGHT...AS LOW PRESSURE LIFTS INTO THE OHIO VALLEY TOMORROW. SUSTAINED WINDS UP TO 20 KNOTS OVER SOUTHERN LAKE HURON WILL PRODUCE WAVES 4 FEET OR SLIGHTLY BETTER...WHICH SHOULD BRUSH THE NEARSHORE WATERS ALONG THE EASTERN THUMB REGION...AND THUS HAVE ISSUED SMALL CRAFT ADVISORIES. THE LOW OF THE OHIO VALLEY WILL THEN TRACK IN BETWEEN THE CENTRAL AND EASTERN GREAT LAKES TOMORROW NIGHT...WITH VERY COLD AIR FOLLOWING FOR SUNDAY AND MONDAY. NORTHWEST WINDS OF AT LEAST 30 KNOTS ARE EXPECTED OVER LAKE HURON WITH THE DEEP MIXING...AND GALES ARE CERTAINLY POSSIBLE LATE SUNDAY AND SUNDAY EVENING. HAVE GONE AHEAD AND ISSUED GALE WATCH FOR THE NORTHERN TWO THIRDS OF LAKE HURON. WITH THE COLD AIRMASS...FREEZING SPRAY WILL LIKELY BE AN ISSUE DURING THIS TIME FRAME AS WELL. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY FROM 6 AM TO 6 PM EST SATURDAY FOR MIZ047>049-053>055-060>063-068>070-075-076-082-083. LAKE HURON...SMALL CRAFT ADVISORY FROM 7 AM TO 7 PM EST SATURDAY FOR LHZ441-442. GALE WATCH FROM SUNDAY AFTERNOON THROUGH LATE SUNDAY NIGHT FOR LHZ361>363. LAKE ST CLAIR...NONE. MICHIGAN WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....SC UPDATE.......SC SHORT TERM...SF LONG TERM....BT/RK MARINE.......BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS JACKSON MS
1104 AM CST SAT JAN 3 2015 .UPDATE... THE PRIMARY ADJUSTMENT TO THE FORECAST THIS MORNING INCLUDES SHIFTING THE SEVERE WEATHER RISK MORE INTO CENTRAL/ERN MS WHERE THE ELEVATED THREAT FOR TORNADOES/DAMAGING WINDS/HAIL CONTINUES. THE FORECAST IS GENERALLY ON TRACK WITH A RISK FOR FLASH FLOODING CONTINUING OVER MOST OF THE AREA...AND ALL ELSE IS GENERALLY ON TRACK. A STRONG SHORTWAVE TROUGH OVER THE SOUTHERN PLAINS WILL LIFT NORTHEAST TODAY WITH MODEST HEIGHT FALLS APPROACH THE AREA THIS AFTERNOON. THE INCREASED FORCING WILL HELP TO REINVIGORATE CONVECTIVE COMPLEX CURRENTLY MOVING TOWARD THE NATCHEZ TRACE CORRIDOR AND GUIDANCE BRINGS INTO ERN MS BY LATE THIS AFTN. THE BIG CONCERN IS GREATER DESTABILIZATION TAKING PLACE OVER SE LA/SRN MS WITH EFFECTIVE LOW LEVEL SHEAR/SRH (200+ M2/S2) AND SFC-BASED INSTABILITY ON THE INCREASE THERE...WE CONTINUE TO BE CONFIDENT IN THE SEVERE WEATHER POTENTIAL AND ELEVATED THREAT AREA GENERALLY ALONG AND SE OF THE NATCHEZ TRACE CORRIDOR AS INTENSIFYING CONVECTION INTERACTS WITH THE IMPROVING ENVIRONMENT WITH LATEST HRRR GUIDANCE SHOWING MID/ UPPER 60S DEWPOINTS UP TO THE GOLDEN TRIANGLE AREA BY EARLY/MID AFTN. THE LATEST NEAR TERM GUIDANCE INDICATES THAT BROKEN LINEAR CONVECTIVE SYSTEM MAY SOLIDIFY IN VICINITY OF CURRENT COLD POOL OVER WRN/CENTRL MS AND GRADUALLY MOVE INTO ERN MS BY EARLY EVNG. AS THE SYSTEM SLOWS DOWN...EXPECT POTENTIAL FOR INCREASING FLASH FLOOD THREAT WITH INTENSE RAINFALL RATES PRODUCING LOCALIZED AREAS OF 3 TO 5 INCHES OVER WET GROUND. /EC/ && .AVIATION...A MIX OF CLOUDS AND CONVECTION WILL RESULT IN MAINLY MVFR/IFR FLIGHT CATEGORIES AT TAF SITES ACROSS THE AREA TODAY INTO TONIGHT. SOME STORMS COULD BE SEVERE THIS AFTERNOON INTO THIS EVENING...ESPECIALLY ACROSS CENTRAL...SOUTH...AND EAST MISSISSIPPI (KHKS...KJAN...KGTR...KMEI...& KHBG)...AND CAPABLE OF PRODUCING DAMAGING WINDS...LARGE HAIL...AND SOME TORNADOES. WHILE SOME LIGHT RAIN WILL LINGER ACROSS THE AREA OVERNIGHT INTO EARLY SUNDAY MORNING...ESPECIALLY IN THE EAST...THE HEAVIEST CONVECTION SHOULD BE EXITING EAST AND SOUTHEAST MISSISSIPPI BETWEEN 01-03Z THIS EVENING. WINDS TODAY WILL BE GUSTY FROM THE SOUTH...BUT WILL GRADUALLY BECOME MORE WESTERLY AND EVENTUALLY NORTHWESTERLY IN THE WAKE OF THE COLD FRONTAL PASSAGE THIS EVENING AND OVERNIGHT. /19/ && .PREV DISCUSSION... /ISSUED 400 AM CST SAT JAN 3 2015/ INCREASING RISK FOR SIGNIFICANT ARCTIC OUTBREAK NEXT WEEK... SHORT TERM...THIS SYSTEM SHOULD MOVE EAST OF AREA BY EARLY MORNING SUNDAY...AND IN THE WAKE OF IT COLD AIR ADVECTION SHOULD RESULT IN WIDESPREAD LOW CLOUDS AND SOME PATCHY LIGHT RAIN AND DRIZZLE INTO AT LEAST EARLY SUNDAY. TEMPS SHOULD BE SOME 20 DEG COOLER SUNDAY THAN SATURDAY. WITH THE SHORTWAVE PASSING THROUGH THE REGION REGIONAL CROSS SECTIONS HOLDS ON TO SOME LOW CLOUDS FOR SUNDAY NIGHT. SO HAVE GENERALLY PARTLY CLOUDY SKIES FOR THAT PERIOD...WHICH WILL HINDER RADIATIONAL COOLING. SO WENT CLOSER TO A MILDER SOLUTION FOR SUNDAY NIGHT./17/ LONG TERM...MONDAY THROUGH FRIDAY...THE MAIN FOCUS OF THE LONG TERM CONTINUES TO BE THE MUCH COLDER AIR THAT IS FORECAST TO AFFECT THE ARKLAMISS REGION DURING THE MIDDLE OF NEXT WEEK. THE FIRST SHOT OF ARCTIC AIR WILL ARRIVE BEHIND THIS WEEKENDS STORM SYSTEM. A 1040MB SURFACE HIGH WILL FILTER INTO THE REGION BEHIND THE FRONT BUT WILL ONLY GIVE A SHORT...GLANCING BLOW AS THIS SFC HIGH WILL BE PROGRESSIVE AND MOVE ACROSS THE OHIO VALLEY BY TUESDAY. THIS SHOT OF COLDER AIR WILL BRING SUBFREEZING LOWS ON MONDAY AND TUESDAY AND COOLER DAYTIME HIGHS FOR MONDAY. THERE WILL BE A SHORT MODERATION IN TEMPERATURES ON TUESDAY BEFORE A DRY COLD FRONT MOVES THROUGH THE REGION. THE AIR BEHIND THIS WILL BE THE COLDEST WE HAVE SEEN YET. MODELS CONTINUE TO AGREE IN A 1050+ MB SURFACE HIGH DIVING SOUTH INTO THE CENTRAL PLAINS. THIS WILL SPREAD A COLD AIRMASS DEEP INTO THE SOUTH WITH SOME POTENTIAL FOR A HARD FREEZE...PARTICULARLY FOR THE HIGHWAY 82 CORRIDOR. THIS WOULD BRING OVERNIGHT LOWS ON WEDNESDAY NIGHT INTO THE TEENS AND DAYTIME HIGHS ON THURSDAY NOT REACHING ABOVE FREEZING. THE REMAINDER OF THE AREA SHOULD SEE LOWS WEDNESDAY NIGHT IN THE TEENS AND 20S BUT SHOULD GET ENOUGH WARMTH ON THURSDAY TO REACH INTO THE UPPER 30S/AROUND 40. GIVEN THE TIGHTENED PRESSURE GRADIENT OVER THE REGION LATER WEDNESDAY INTO EARLY THURSDAY...THIS WILL CREATE WIND CHILL READINGS INTO THE SINGLE DIGITS AND LOWER TEENS. OVERALL THIS PATTERN WILL LEAD TO AN EXTREMELY COLD AND RAW PERIOD AS THE SFC HIGH STICKS AROUND OVER THE REGION THROUGH THE END OF THE WEEK. /28/ && .JAN WATCHES/WARNINGS/ADVISORIES... MS...FLASH FLOOD WATCH THROUGH THIS EVENING FOR MSZ030-031-033-038- 039-045-046-051-052-056>058-064>066-072>074. FLASH FLOOD WATCH UNTIL 6 PM CST THIS EVENING FOR MSZ018-019- 025>029-032-034>037-040>044-047>050-053>055-059>063. LA...FLASH FLOOD WATCH UNTIL 6 PM CST THIS EVENING FOR LAZ007>009-015- 016-023>026. AR...FLASH FLOOD WATCH UNTIL 6 PM CST THIS EVENING FOR ARZ074-075. && $$
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
427 PM CST Sat Jan 3 2015 .SHORT TERM...(This Evening through Sunday Night) Issued at 426 PM CST SAT JAN 3 2015 Tonight: The second phase of the approaching winter system will quickly make its presence felt over our CWA. The latest satellite and radar data reveal the rapid development of the deformation zone precipitation shield across south central and central KS. Satellite trends appear to support the latest operational NAM, GFS and ECMWF which depict a more southern track (vs yesterday`s solutions) of the main precipitation. The HRRR and RUC also confirm this. So, with only minor adjustments needed have shifted the axis of heavier snowfall a bit further south. Model output via Bufkit and the operational model snow algorithms all point to a general 1-2 inch swath with isolated amounts to 3 inches possible from east central KS through west central MO. Snow amounts will be limited by 1) initially falling as rain and 2) melting at onset due to above freezing temperatures. An expected quick transition to snow due to strong dynamic forcing within the deformation cloud shield and the eventual surge of strong cold air advection should mitigate this melting. Also of note is the convective looking nature of the growing deformation cloud shield. Close inspection of Bufkit data and model soundings suggest CSI may be possible for a brief period early this evening with elevated CAPE values approaching 100 J/kg. Evening shift will need to keep an eye on this for possible thunder-snow and rapid increase in snow rates. Strong cold air advection will rush from the Central Plains this evening. Upstream obs show single digit temperatures and wind gust of 35-40 mph. Thus blowing snow tied to the baroclinc zone snow which will form across southeast NE this evening will be added to the northern and western CWA. Have also allowed light snow/flurries to linger well after midnight as ice crystals will be produced down into the boundary layer as temperatures fall to -15C within the saturated cloud layer between 2500-5000ft agl. Due to the combo of 25-35 mph winds and single digit temperatures have added a wind chill advisory for the northwest tip of MO. Sunday and Sunday Night: Brutally cold. That`s all you need to know. A 1041 mb surface high will sit over KS and western MO during this period. A stiff northwest wind will diminish from west to east in the morning and clouds will clear so we`ll get some relief from the cold. However, the weight of h8 temperatures of -10C to -15C will limit highs to mainly the teens. Some mid level warm advection clouds streaming in from NE may be the saving grace for below zero temperatures Monday night. That plus very light winds may only generate wind chills from -5 to -15F. .LONG TERM...(Monday through Saturday) Issued at 426 PM CST SAT JAN 3 2015 Looking ahead to the extended...everyone may want to keep those heavy winter coats out a while longer. The forecast continues to remain cold and mostly dry until late in the upcoming work week. An upper level ridge will remain planted across the western US coast with a very wide longwave trough over the remainder of the US. This places the CWA in northwest flow aloft with a number of disturbances translating through the main flow. Each of these systems will provide a reinforcing shot of cold air into the region. With snow remaining on the ground, airmass modification will be minimal allowing morning lows to tumble into the low single digits with a few negative single digits along the MO/IA border Monday morning. While the EC and GFS 850mb temperatures are off a few degrees from each other, they are still bringing in temperatures ranging from -17 to -25 C over the CWA. Thus, it is likely that lows will plummet into the negative singles Wed morning across the northern half of CWA, and then low singles on either side of zero by Thurs morning. High temperatures look to warm into the upper teens and into the low and mid 20s much of the week, except Wed when it will be tough to climb into the teens. Precip-wise, the northeast corner of the CWA may see some light snow Mon night as one of the previously mentioned systems glances the area. Long-range models are also indicating that the region may see increasing chances for precip late in the week, but given that it is towards the end of the extended a lot can, and probably will, change over the next several days as the system begins to evolve. && .AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon) Issued at 1230 PM CST SAT JAN 3 2015 Passing of upper shortwave has stripped away deeper moisture and IFR/MVFR cigs from eastern KS and northwest MO. However, the MVFR cigs remain extremely close to the terminals and should lie along and south of an KIXD to Kirksville line this afternoon. Short range models like the RUC and 12z NAM seem to have a decent handle on this. Will allow MVFR cigs to move back into the Kansas City terminals late this afternoon as next wave of precipitation spreads quickly northeast from KS. Will likely see an hour or two of rain before rapid transition to snow. As winds shift and increase from the northwest this evening they will become quite gusty with blowing snow likely persisting past midnight. Should see VFR conditions return by mid Sunday morning as clouds scatter out. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...WINTER WEATHER ADVISORY until 3 AM CST Sunday FOR KSZ025-057- 103>105. WINTER WEATHER ADVISORY until 6 AM CST Sunday FOR KSZ102. MO...WINTER WEATHER ADVISORY until 3 AM CST Sunday FOR MOZ013>017- 020>025-028>033-037>039-043-044. WINTER WEATHER ADVISORY until 6 AM CST Sunday FOR MOZ001>008-011- 012. WIND CHILL ADVISORY from 3 AM to 9 AM CST Sunday FOR MOZ001-002- 011. && $$ SHORT TERM...MJ LONG TERM...PMM AVIATION...MJ
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1238 PM CST Sat Jan 3 2015 .UPDATE... Issued at 1230 PM CST SAT JAN 3 2015 Have lowered afternoon PoPs and raised temperatures for this afternoon. Shortwave trough has moved quickly through MO and stripped away deeper moisture and heavier rainfall, leaving behind shallow saturated boundary layer and areas of drizzle generally south of a Kansas City to Kirksville. Significant dry slot noted in water vapor imagery moving through eastern KS/western MO has resulted in some breaks in the overcast and warmer temperatures. So, have raised highs accordingly. Still looking like deformation precipitation shield will lift rapidly northeast this afternoon and evening. Raising temperatures this afternoon may lead to an extra hour or two of rain or rain/snow mix before total transition. If transition takes longer it likely would affect snow amounts negatively. HRRR and 12z NAM/GFS continue on a path of a more southern track of the deformation precipitation band and may need to shift heavier snow band (used in a relative sense as snow amounts still look like 1-2" with isolated 3"). && .SHORT TERM...(Today through Monday) Issued at 358 AM CST SAT JAN 3 2015 Main focus in the short term will be wintry precipitation chances today and tonight as a low pressure system pushes northeast across the region. In the near term, mainly liquid precipitation out ahead of the surface low will lift NE across the southeastern two-thirds of the CWA. Surface temperatures in areas where precipitation is expected this morning are mainly at 32 degrees or higher, and dewpoint temperatures are also hovering right at the freezing mark, preventing any wet-bulb effects from lowering surface temperatures. Have still included a chance of freezing drizzle in case some very light precipitation on the northern edge falls over sub-freezing temperatures, but do not expect more than a light glaze of ice. Morning precipitation will begin to clear off to the northeast as the dry slot moves in between 10 AM and noon, leaving patchy drizzle and stratus across the region. A second round of precipitation associated with a rather pronounced PV anomaly is still expected to lift from the TX panhandle into our far western CWA by late afternoon to early evening, and will spread northeast through the night. Precipitation type will likely begin as rain, but will mix with and then transition to snow as colder air wraps in on the back side of the surface low after 21z. 00z NAM/GFS continued a farther south trend in highest precipitation totals, but 00z EC and 06z NAM have pulled precipitation back a touch north, so have not jumped to significantly change the location of highest precipitation totals for this evening and tonight. Precipitation totals of 0.15" to at most 0.2" are still anticipated with the second area of wintry precip tonight, despite the strength of the system and availability of moisture. The window for precip in any one area will be fairly brief due to the speed of the system and the arrival of dry air undercutting the deep moisture, resulting in a quick 1-2" of total snow within a few hour period. A brief period of blowing snow will also be a concern across far northeast KS and northwest and northern MO after 03z as gusty northwest winds sweep into the region, so have added the remainder of our northern counties into the winter weather advisory for 1-2" snow and blowing snow. Snowfall should taper quickly between 09z-12z Sunday morning as frigid, dry air surges into the region from the northwest. Wind chill values on Sunday morning are still expected to fall into the -5 to -15 degree range, and may fall as low as -20 in far northwest MO before 15z. May need a small wind chill advisory for areas that will fall below -15 F Sunday morning, but will wait to issue until at least the morning precipitation clears out of the region and colder air starts to advance into the Plains. Very cold and mainly quiet conditions are expected Sunday night through Monday night. A brief brush of light snow is possible across northeast MO late Monday afternoon through Monday night, but most accumulating snow will likely stay north of the CWA. .LONG TERM...(Tuesday through Friday) Issued at 358 AM CST SAT JAN 3 2015 The extended forecast looks to be dry and rather cold, as Canadian air intrudes into the area. Mid range and extended models develop a N-S oriented elongated surface ridge, which will bring a steady diet of cold air to the Central Plains and the Lower Missouri River Valley. There is some discrepancy between the ECMWF and the GFS regarding just how cold the air mass will be. The EC indicates 850 mb temps down in the -15C to -20C range, while the GFS only drops into the -10C to -12C range. At any rate, it looks rather chilly through the middle to late week, with highs in the teens and 20s, and lows dropping to the single digits. These temperatures could drop even more with ample snow fall north of the forecast area, which would mitigate the modification of the cold air. The next good chance for precip looks to be late next week, but models differ quite a bit with that solution at this point, so will keep specifics out for now. && .AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon) Issued at 1230 PM CST SAT JAN 3 2015 Passing of upper shortwave has stripped away deeper moisture and IFR/MVFR cigs from eastern KS and northwest MO. However, the MVFR cigs remain extremely close to the terminals and should lie along and south of an KIXD to Kirksville line this afternoon. Short range models like the RUC and 12z NAM seem to have a decent handle on this. Will allow MVFR cigs to move back into the Kansas City terminals late this afternoon as next wave of precipitation spreads quickly northeast from KS. Will likely see an hour or two of rain before rapid transition to snow. As winds shift and increase from the northwest this evening they will become quite gusty with blowing snow likely persisting past midnight. Should see VFR conditions return by mid Sunday morning as clouds scatter out. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...WINTER WEATHER ADVISORY until Midnight CST tonight FOR KSZ025- 057-103>105. WINTER WEATHER ADVISORY from 6 PM this evening to 6 AM CST Sunday FOR KSZ102. MO...WINTER WEATHER ADVISORY until Midnight CST tonight FOR MOZ013>017-020>025-028>033-037>039-043-044. WINTER WEATHER ADVISORY from 6 PM this evening to 6 AM CST Sunday FOR MOZ001>008-011-012. && $$ UPDATE...MJ SHORT TERM...Laflin LONG TERM...Leighton AVIATION...MJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
125 PM EST SAT JAN 3 2015 .SYNOPSIS... A STORM SYSTEM IS EXPECTED TO BRING A MIX OF SNOW, SLEET AND FREEZING RAIN ACROSS NORTHEAST PENNSYLVANIA AND CENTRAL NEW YORK ON TODAY. THE WINTRY MIX WILL THEN CHANGE TO RAIN TONIGHT...FOLLOWED BY WARMER TEMPERATURES AND SHOWERS ON SUNDAY. A SHARP COOL DOWN WILL FOLLOW FOR SUNDAY NIGHT INTO EARLY NEXT WEEK ACCOMPANIED BY STRONG WINDS AND LAKE EFFECT SNOW. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1050 AM UPDATE... PCPN ON TRACK TO MV INTO CWA FM CNTRL PA AS WMFNT IS DVLPNG ACRS THE MIDWEST INTO NWPA AT THIS TIME. STRONG ISENTROPIC UPGLIDE ALLOWING PCPN TO BREAK OUT BACK TO THE SOUTHWEST. AS WARM ADVECTION STRENGTHENS OVR THE NEXT SVRL HRS ON DVLPNG LOW-LVL JET EXPECT PCPN TO ENCOMPASS ENTIRE CWA BY 20Z THIS AFTN. HV DELAYED ONSET BY AN HR OR TWO AS RADAR IS PICKING UP ON MID-DECK WITH JUST VRY LGT SNOW NOW FALLING OVR SRN LUZERNE CNTY. RADAR POP-UP SKEW-T INDICATING ENTIRE COLUMN BLO FRZG CWA-WIDE WITH 800MB TEMPS WARMING TWD 0C AS OF 1530Z. THIS SEEMS TO CORRELATE WITH LATEST HIRES MODELS, INCLUDING HRRR AND RAP. STILL EXPECTING SVRL HRS OF SNOW AT THE ONSET. AS TEMPS ALOFT WARM, EXPECT A MIX OF SLEET AND FZRA TO WORK IN AS FAR EAST AS A ONONDAGA-PIKE CNTY LINE BY 21Z. CLDR TEMPS WL BE ABLE TO HOLD IN ACRS THE EAST THE LONGEST WITH SNOW POSSIBLE UNTIL CLOSE TO 00Z. QUESTION CONTINUES TO CNTR ON HOW MUCH FZRA CAN BE EXPECTED AS CLD LYR LKLY TO BE ALMOST 4KFT DEEP WITH MAX WARM LYR TEMPS ARND 800MB OF +3C TO +4C. AS COLD LYR DIMINISHES IN DEPTH AND TEMPS WARM ALOFT TO +6C BTWN 21Z AND 00Z EXPECT THIS TO BE MOST LKLY TIME FOR FZRA ACRS THE CWA. HWVR, THIS LEADS TO THE QUESTION OF HOW MUCH ICE WL ACTUALLY BE ABLE TO ACCRETE AS WARM AIR IS DRAGGED DOWN FM ALOFT. HV MASSAGED HRLY T/TD VALUES AND DELAYED ONSET OF PCPN BY AN HR OR TWO TO GET A BETTER HANDLE ON CURRENT CONDITIONS BUT NO MAJOR CHGS NEEDED AT THIS TIME. PREV DISCUSSION BLO... MAIN FOCUS FOR THE NEAR TERM CONTINUES TO BE WINTRY MIX DUE TO ARRIVE BY LATER TODAY AS A STRENGTHENING LOW RIDES UP TO OUR WEST. EXPECT SNOW TO BREAK OUT FROM SW TO NE BEGINNING NEAR MIDDAY WITH MOST AREAS SEEING A FEW HOURS WORTH OF SNOWFALL BEFORE THE TRANSITION IN P-TYPES BEGINS TOWARD THE MID TO LATE AFTERNOON. GENERALLY LOOKING AT 1 TO 2 INCHES OF SLUSHY SNOW ACCUMULATION BEFORE THIS OCCURS. AS THE WARMER AIR BEGINS TO MOVE IN ALOFT ASSOCIATED WITH STRONG LLJ EXPECT TRANSIT ON TO SLEET/FREEZING RAIN TO OCCUR. PROFILES CONTINUE TO INDICATE A RELATIVELY DEEP COLD LAYER IN THE LOW LEVELS WHICH INDICATES MORE SLEET THAN FREEZING RAIN WILL OCCUR DURING THE TRANSITION BEFORE THE CHANGE TO ALL RAIN OCCURS TONIGHT. HOWEVER GIVEN THAT MOST OF THE AREA LOOKS TO SEE AT THE LEAST A VERY BRIEF PERIOD OF FREEZING RAIN ALONG WITH THE SNOW AND SLEET WE DO EXPECT SOME SLIPPERY CONDITIONS SO MAINTAIN THE WINTER WEATHER ADVISORIES. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... THE TRANSITION FROM SNOW TO A WINTRY MIX TO RAIN WILL BE ONGOING EARLY IN THE PERIOD. WESTERN PORTIONS OF THE CWA WILL HAVE CHANGED MAINLY TO RAIN BY EARLY EVENING WITH THE TRANSITION ZONE AT THIS TIME RIGHT NEAR THE I-81 CORRIDOR WHERE THE WINTRY MIX WILL BE OCCURRING WITH TEMPS NEAR NEAR FREEZING. AS THE EVENING PROGRESSES THIS TRANSITION ZONE WILL SHIFT EAST WITH THE EASTERN AREAS LINGERING WITH SLEET AND FREEZING RAIN UNTIL ABOUT MIDNIGHT AS COLD AIR STRUGGLES TO GET OUT OF THE MOUNTAINS AND MOHAWK VALLEY. AS MENTIONED, MODELS CONTINUE BE IN PRETTY GOOD OVERALL AGREEMENT BUT AS IS TYPICAL, THE NAM IS COLDEST IN THE LOW LEVELS AND WE LEANED TONIGHT`S TEMPS IN THE EAST TOWARD NAM SOLUTION AS IT TENDS TO DUE QUITE WELL WITH THESE TYPE OF COLD AIR DAMMING SCENARIOS. FOLLOWING THE CHANGE OVER FROM WINTRY PRECIP, RAIN CONTINUES OVERNIGHT INTO SUNDAY MORNING WITH TEMPS CONTINUING TO RISE. WHILE THIS IS NOT EXPECTED TO BE ANY TYPE OF MAJOR HYDRO EVENT, IT IS WORTH MENTIONING THAT TOTAL QPF AMOUNTS OF 1 TO 1.5 INCHES ARE FORECAST BY THE TIME THE RAIN WINDS DOWN TO A FEW SHOWERS BY AROUND MIDDAY SUNDAY. WE DON`T EXPECT FLOODING BUT THIS WILL BE ENOUGH TO CAUSE RISES ON RIVERS. CONDITIONS WILL BE VERY MILD WITH JUST A FEW SHOWERS BY SUNDAY AFTERNOON. HIGHS WILL RANGE FROM THE MID 40S TO LOW 50S. THE WARMTH WILL BE SHORT LIVED AS A STRONG COLD FRONT COMES THROUGH SUNDAY EVENING WITH SHOWERS TRANSITIONING TO SNOW SHOWERS AND POTENTIALLY SIGNIFICANT LAKE EFFECT SNOW BEGINNING TO SET UP SE OF LAKE ONTARIO. THE COLD AIR AND SNOW SHOWERS / LAKE EFFECT WILL ALSO BE ACCOMPANIED BY STRONG WINDS LIKELY GUSTING AT LEAST 30 TO 40 MPH. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... 1 PM UPDATE... BITTERLY COLD AIR AND LAKE EFFECT SNOW WILL DOMINATE THE LONG TERM PERIOD. BEHIND A DEPARTING CLIPPER TUESDAY NIGHT INTO EARLY WEDNESDAY, THE FIRST CHUNK OF COLDER AIR WILL MOVE ACROSS OUR AREA. LAKE EFFECT SNOW WILL DEVELOP SOUTHEAST OF THE LAKES ON A WEST TO WEST- NORTHWEST WIND. A SECOND AND MUCH MORE IMPRESSIVE SURGE OF ARCTIC AIR WILL MOVE IN WEDNESDAY NIGHT INTO THURSDAY. 850 TEMPS FALL INTO THE MID 20S BELOW ZERO BY 12Z THURSDAY. LOWS BELOW ZERO ARE LIKELY BOTH THURSDAY AND FRIDAY MORNING. HIGHS THURSDAY MAY NOT GET OUT OF THE SINGLE DIGITS IN SOME AREAS. WITH A NORTHWEST WIND THROUGH THE PERIOD, PERIODS OF LAKE EFFECT SNOW WILL BE LIKELY. THIS MAY BE A BIT TEMPERED BY THE LOW INVERSION HEIGHTS (SHALLOW ARCTIC AIR). && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... WIDESPREAD IFR VSBYS THIS AFTERNOON/EVENING IN WINTRY MIX CHANGING TO RAIN. WIDESPREAD IFR CIGS WITH ALT MINS LIKELY AND AIRPORT MINS POSSIBLE AT KBGM. WIDESPREAD PRECIPITATION WILL CONTINUE ACROSS THE TERMINALS THROUGH EARLY EVENING. AFTER A 1 TO 3 HOUR PERIOD OF SNOW/SLEET WITH IFR VSBYS, WE WILL SEE A TRANSITION TO FREEZING RAIN AND THEN ALL RAIN BY 02Z. ICING WILL LAST LONGEST AT KBGM AND KRME, AND SHORTEST AT KAVP AND KELM. SEE TAFS FOR SPECIFICS. BEYOND THE CHANCES FOR ICING THROUGH LATE AFTERNOON, BIGGEST AVIATION CONCERN EARLY TONIGHT WITH VERY STRONG SOUTHEAST WINDS AS LOW AS 2,000 FEET ABOVE THE SURFACE. AFTER 06Z WINDS WHILE WINDS WILL STILL BE STRONG, HIGHEST RISK FOR LLWS WILL BE ENDING. AS THAT HAPPENS IFR CIGS WILL LOWER WITH TIME. ALT MINS WILL BECOME LIKELY IN A MOIST SOUTHEAST FLOW. WIDESPREAD IFR CIGS CAN BE FOUND WELL TO OUR SOUTHWEST AT THE PRESENT SO THIS IS A HIGH CONFIDENCE FORECAST FOR IFR CONDITIONS. AT BGM, BASED ON SOUNDINGS AND CURRENT OBS, AIRPORT MINS WILL BE APPROACHED BETWEEN 06Z AND 15Z. IFR CIGS CONTINUE THROUGH THE END OF THE TAF PERIOD. ANOTHER PERIOD OF LLWS IS POSSIBLE AFTER 15Z SUNDAY BUT TOO FAR OUT TO INCLUDE IN THE TAFS JUST YET. OUTLOOK... MON/MON NGT...SCT SNOW SHOWERS AND BRIEF RESTRICTIONS WITH GUSTY WINDS...BUT SIGNIFICANT RESTRICTIONS POSSIBLE KSYR-KRME FROM LAKE EFFECT SNOW. TUE/WED...RESTRICTIONS EXPECTED IN -SN AT ALL TERMINALS TUE AS CLIPPER PASSES...THEN LAKE EFFECT -SHSN BRINGING RESTRICTIONS TO NY TERMINALS ON WED. THUR...MAINLY VFR BUT MVFR/IFR POSSIBLE NORTHERN TERMINALS IN LAKE SNOW. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ040. WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR PAZ038- 039-043-044-047-048-072. NY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ009- 036-037-045-046-057-062. WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR NYZ015>018-022>025-044-055-056. && $$ SYNOPSIS...PCF NEAR TERM...PCF/PVF SHORT TERM...PCF LONG TERM...HEDEN AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1048 AM EST SAT JAN 3 2015 .SYNOPSIS... A STORM SYSTEM IS EXPECTED TO BRING A MIX OF SNOW, SLEET AND FREEZING RAIN ACROSS NORTHEAST PENNSYLVANIA AND CENTRAL NEW YORK ON TODAY. THE WINTRY MIX WILL THEN CHANGE TO RAIN TONIGHT...FOLLOWED BY WARMER TEMPERATURES AND SHOWERS ON SUNDAY. A SHARP COOL DOWN WILL FOLLOW FOR SUNDAY NIGHT INTO EARLY NEXT WEEK ACCOMPANIED BY STRONG WINDS AND LAKE EFFECT SNOW. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1050 AM UPDATE... PCPN ON TRACK TO MV INTO CWA FM CNTRL PA AS WMFNT IS DVLPNG ACRS THE MIDWEST INTO NWPA AT THIS TIME. STRONG ISENTROPIC UPGLIDE ALLOWING PCPN TO BREAK OUT BACK TO THE SOUTHWEST. AS WARM ADVECTION STRENGTHENS OVR THE NEXT SVRL HRS ON DVLPNG LOW-LVL JET EXPECT PCPN TO ENCOMPASS ENTIRE CWA BY 20Z THIS AFTN. HV DELAYED ONSET BY AN HR OR TWO AS RADAR IS PICKING UP ON MID-DECK WITH JUST VRY LGT SNOW NOW FALLING OVR SRN LUZERNE CNTY. RADAR POP-UP SKEW-T INDICATING ENTIRE COLUMN BLO FRZG CWA-WIDE WITH 800MB TEMPS WARMING TWD 0C AS OF 1530Z. THIS SEEMS TO CORRELATE WITH LATEST HIRES MODELS, INCLUDING HRRR AND RAP. STILL EXPECTING SVRL HRS OF SNOW AT THE ONSET. AS TEMPS ALOFT WARM, EXPECT A MIX OF SLEET AND FZRA TO WORK IN AS FAR EAST AS A ONONDAGA-PIKE CNTY LINE BY 21Z. CLDR TEMPS WL BE ABLE TO HOLD IN ACRS THE EAST THE LONGEST WITH SNOW POSSIBLE UNTIL CLOSE TO 00Z. QUESTION CONTINUES TO CNTR ON HOW MUCH FZRA CAN BE EXPECTED AS CLD LYR LKLY TO BE ALMOST 4KFT DEEP WITH MAX WARM LYR TEMPS ARND 800MB OF +3C TO +4C. AS COLD LYR DIMINISHES IN DEPTH AND TEMPS WARM ALOFT TO +6C BTWN 21Z AND 00Z EXPECT THIS TO BE MOST LKLY TIME FOR FZRA ACRS THE CWA. HWVR, THIS LEADS TO THE QUESTION OF HOW MUCH ICE WL ACTUALLY BE ABLE TO ACCRETE AS WARM AIR IS DRAGGED DOWN FM ALOFT. HV MASSAGED HRLY T/TD VALUES AND DELAYED ONSET OF PCPN BY AN HR OR TWO TO GET A BETTER HANDLE ON CURRENT CONDITIONS BUT NO MAJOR CHGS NEEDED AT THIS TIME. PREV DISCUSSION BLO... MAIN FOCUS FOR THE NEAR TERM CONTINUES TO BE WINTRY MIX DUE TO ARRIVE BY LATER TODAY AS A STRENGTHENING LOW RIDES UP TO OUR WEST. EXPECT SNOW TO BREAK OUT FROM SW TO NE BEGINNING NEAR MIDDAY WITH MOST AREAS SEEING A FEW HOURS WORTH OF SNOWFALL BEFORE THE TRANSITION IN P-TYPES BEGINS TOWARD THE MID TO LATE AFTERNOON. GENERALLY LOOKING AT 1 TO 2 INCHES OF SLUSHY SNOW ACCUMULATION BEFORE THIS OCCURS. AS THE WARMER AIR BEGINS TO MOVE IN ALOFT ASSOCIATED WITH STRONG LLJ EXPECT TRANSIT ON TO SLEET/FREEZING RAIN TO OCCUR. PROFILES CONTINUE TO INDICATE A RELATIVELY DEEP COLD LAYER IN THE LOW LEVELS WHICH INDICATES MORE SLEET THAN FREEZING RAIN WILL OCCUR DURING THE TRANSITION BEFORE THE CHANGE TO ALL RAIN OCCURS TONIGHT. HOWEVER GIVEN THAT MOST OF THE AREA LOOKS TO SEE AT THE LEAST A VERY BRIEF PERIOD OF FREEZING RAIN ALONG WITH THE SNOW AND SLEET WE DO EXPECT SOME SLIPPERY CONDITIONS SO MAINTAIN THE WINTER WEATHER ADVISORIES. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... THE TRANSITION FROM SNOW TO A WINTRY MIX TO RAIN WILL BE ONGOING EARLY IN THE PERIOD. WESTERN PORTIONS OF THE CWA WILL HAVE CHANGED MAINLY TO RAIN BY EARLY EVENING WITH THE TRANSITION ZONE AT THIS TIME RIGHT NEAR THE I-81 CORRIDOR WHERE THE WINTRY MIX WILL BE OCCURRING WITH TEMPS NEAR NEAR FREEZING. AS THE EVENING PROGRESSES THIS TRANSITION ZONE WILL SHIFT EAST WITH THE EASTERN AREAS LINGERING WITH SLEET AND FREEZING RAIN UNTIL ABOUT MIDNIGHT AS COLD AIR STRUGGLES TO GET OUT OF THE MOUNTAINS AND MOHAWK VALLEY. AS MENTIONED, MODELS CONTINUE BE IN PRETTY GOOD OVERALL AGREEMENT BUT AS IS TYPICAL, THE NAM IS COLDEST IN THE LOW LEVELS AND WE LEANED TONIGHT`S TEMPS IN THE EAST TOWARD NAM SOLUTION AS IT TENDS TO DUE QUITE WELL WITH THESE TYPE OF COLD AIR DAMMING SCENARIOS. FOLLOWING THE CHANGE OVER FROM WINTRY PRECIP, RAIN CONTINUES OVERNIGHT INTO SUNDAY MORNING WITH TEMPS CONTINUING TO RISE. WHILE THIS IS NOT EXPECTED TO BE ANY TYPE OF MAJOR HYDRO EVENT, IT IS WORTH MENTIONING THAT TOTAL QPF AMOUNTS OF 1 TO 1.5 INCHES ARE FORECAST BY THE TIME THE RAIN WINDS DOWN TO A FEW SHOWERS BY AROUND MIDDAY SUNDAY. WE DON`T EXPECT FLOODING BUT THIS WILL BE ENOUGH TO CAUSE RISES ON RIVERS. CONDITIONS WILL BE VERY MILD WITH JUST A FEW SHOWERS BY SUNDAY AFTERNOON. HIGHS WILL RANGE FROM THE MID 40S TO LOW 50S. THE WARMTH WILL BE SHORT LIVED AS A STRONG COLD FRONT COMES THROUGH SUNDAY EVENING WITH SHOWERS TRANSITIONING TO SNOW SHOWERS AND POTENTIALLY SIGNIFICANT LAKE EFFECT SNOW BEGINNING TO SET UP SE OF LAKE ONTARIO. THE COLD AIR AND SNOW SHOWERS / LAKE EFFECT WILL ALSO BE ACCOMPANIED BY STRONG WINDS LIKELY GUSTING AT LEAST 30 TO 40 MPH. && .LONG TERM /MONDAY THROUGH FRIDAY/... 430 AM UPDATE... FORECAST UPDATED FOR LATEST MODEL TRENDS AND WPC GUIDANCE. WELL ALIGNED FLOW MONDAY THROUGH MONDAY EVENING FOR POTENTIALLY SIGNIFICANT LAKE EFFECT SNOW MAINLY NORTH OF THE THRUWAY...WITH SIGNS OF GOOD UPSTREAM LAKE-TO-LAKE CONNECTIONS. WE MAY HAVE TO SOON CONSIDER HOISTING A LAKE EFFECT WATCH FOR AT LEAST NORTHERN ONEIDA COUNTY. ALSO...STRONG COLD AIR ADVECTION MONDAY WILL MEAN NON- DIURNAL TEMPERATURES...THAT IS STEADY OR FALLING DURING THE DAY. WINDS ALSO LOOK QUITE STOUT AS THE COLD AIR MOVES IN...WITH PEAK GUSTS OF AT LEAST 30-40 MPH LOOKING PROBABLE. THE COMBINED EFFECTS OF THOSE WINDS AND TEMPERATURES WILL LIKELY YIELD WIND CHILLS FALLING INTO THE SINGLE DIGITS MONDAY AFTERNOON AND EVENING. CONFIDENCE HAS INCREASED FOR AN AREAWIDE FEW FLUFFY INCHES OF SNOW FROM CLIPPER SYSTEM TUESDAY. HAVE ACCORDINGLY ADJUSTED FORECAST TO LIKELY FOR SNOW CHANCES. AS ALREADY DISCUSSED BELOW...EVEN COLDER AIR EN ROUTE. LOOKS LIKE REAL WINTER IS HERE. PREVIOUS DISCUSSION... LK EFFECT SNOW WL BE ONGOING ACRS NRN ZONES AT THE START OF THE LONG TERM PD. SFC HIPRES WL BUILD INTO THE MID-ATLANTIC STATES WITH RIDGE AXIS BRIEFLY LEADING TO QUIET WX TUE MRNG. WK CLIPPER WL TRACK THRU THE CWA ON TUESDAY LEADING TO A FAIRLY GOOD SHOT OF LIGHT SNOW QUICKLY FOLLOWED BY LAKE EFFECT ONCE AGAIN. NW FLOW WL CONTINUE THRU THURSDAY FOLLOWED QUICKLY BY ANOTHER CLIPPER TWD THE END OF NEXT WEEK. COLD AIR FLOWING STRAIGHT OUT OF CANADA WL BRING THE COLDEST TEMPS OF THIS WINTER TO THE AREA THUR MRNG. MED RANGE MODELS INDICATING 1000-500MB THICKNESSES DROPPING AOB 490DM. THIS WL LKLY TRANSLATE TO LOWS DROPPING TO ARND OR JUST BLO 0F. HIGHS ON THURSDAY WL ONLY BE ABLE TO RECOVER INTO THE TEENS SO IT APPEARS THAT A COLD AND ACTIVE PATTERN IS ON TAP FOR THE NEXT WEEK. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... 12Z UPDATE... QUIET AND VFR INITIALLY THIS MORNING...THEN VERY COMPLICATED FOR THE REMAINDER OF THE TAF PERIOD INCLUDING MULTIPLE PRECIPITATION TYPES AND DEVELOPMENT OF LLWS AS MOIST STORM SYSTEM IMPACTS THE REGION. PLEASE SEE TAFS FOR SPECIFICS ON EXPECTED TIMING...BUT GENERALLY SPEAKING SNOW WILL OVERSPREAD THE AREA SOUTHWEST TO NORTHEAST BETWEEN 17Z-20Z WITH RAPID DROP TO IFR VIS...LOWER THAN THAT NOT OUT OF THE QUESTION. THE SNOW WILL THEN MIX WITH SLEET MID AFTERNOON BEFORE CHANGING TO FREEZING RAIN OR RAIN LATE AFTERNOON- EARLY EVENING /BEST CHANCE OF BRIEF PERIOD OF -FZRA WILL BE KBGM- KRME/. AROUND THIS TIME...45-55 KT SSE JET WILL SETTLE LOW ENOUGH OFF THE GROUND FOR LLWS CONDITIONS THROUGH EVENING. SURFACE WINDS WILL BE VARIABLE OR LIGHT ESE PRE- DAWN...THEN INCREASE DURING THE DAY TO STEADY SE ROUGHLY 10 KTS OR SO WITH GUSTS INTO UPPER TEENS KTS LATE AFTERNOON ONWARD. KAVP-KBGM-KELM WINDS TO SLACKEN SOMEWHAT LATER TONIGHT WHILE VEERING MORE SOUTHERLY...WITH LOSS OF LLWS BUT CONTINUED -RA AND IFR CIG. OUTLOOK... SUN...MVFR TO IFR EARLY SUNDAY MORNING WITH RAIN...IMPROVING BY SUNDAY AFTERNOON WITH ONLY SCT -SHRA. MON/MON NGT...SCT SNOW SHOWERS AND BRIEF RESTRICTIONS WITH GUSTY WINDS...BUT SIGNIFICANT RESTRICTIONS POSSIBLE KSYR-KRME FROM LAKE EFFECT SNOW. TUE/WED...RESTRICTIONS EXPECTED IN -SN AT ALL TERMINALS TUE AS CLIPPER PASSES...THEN LAKE EFFECT -SHSN BRINGING RESTRICTIONS TO NY TERMINALS ON WED. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR PAZ040. WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR PAZ038- 039-043-044-047-048-072. NY...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR NYZ009- 036-037-045-046-057-062. WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR NYZ015>018-022>025-044-055-056. && $$ SYNOPSIS...PCF NEAR TERM...PCF/PVF SHORT TERM...PCF LONG TERM...MDP/PVF AVIATION...MDP
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
132 AM EST SAT JAN 3 2015 .SYNOPSIS... A DEVELOPING LOW PRESSURE SYSTEM OVER THE LOWER MISSISSIPPI VALLEY WILL BRING A WINTRY MIX TO CENTRAL PENNSYLVANIA SATURDAY...FOLLOWED BY RAIN SATURDAY NIGHT INTO SUNDAY. THE MAIN STORY NEXT WEEK WILL BE MUCH COLDER TEMPERATURES WITH NO MAJOR STORMS ON THE HORIZON. && .NEAR TERM /UNTIL 1 PM THIS AFTERNOON/... IT IS ALREADY STARTING TO RAIN VERY LIGHTLY IN CENTRAL WV. THE CORRESPONDING RADAR ECHOES SEEM TO BE SLIDING MORE EAST THAN NORTH AT THIS POINT AND THE HRRR AND RUC /AND NAM/ HAVE A GOOD HANDLE ON THE CURRENT SITUATION. WILL FOLLOW THAT GUIDANCE TRIO AND KEEP POPS OUT UNTIL AFTER 09Z...THEN TRY TO PAINT A GRADUAL SPREAD TO THE NE OF ABOUT 35 MPH. THE PRECIP DOES LOOK TO BE VERY LIGHT AT ONSET AND THEREFORE THE INITIAL P-TYPE WILL BE A MIX OF JUST ABOUT ANYTHING MADE OF WATER LESS THAN 100C. MOST LIKELY THE PRECIP WILL BE FALLING THRU A 4-5KFT DEEP LAYER BELOW FZG...AND SLEET OR SNOW WILL DOMINATE THE FIRST COUPLE OF HOURS ON THE LEADING EDGE OF THE PRECIP. THE HEAVIER SHOT OF PRECIP THRU NOON SEEMS TO BE ACROSS THE NWRN MTS...AND ONLY LIGHT AND SPOTTY PRECIP IS EXPECTED S/E OF UNV AND SEG. MOST LOCATIONS WILL SEE SOMETHING FALLING FROM THE SKY WHICH...WHEN PROPERLY HEATED...WOULD MELT TO WATER. && .SHORT TERM /1 PM THIS AFTERNOON THROUGH 6 PM SUNDAY/... PTYPES/ONSET/DURATION REMAIN THE MOST CHALLENGING PART OF THE FCST BUT THE OVERALL SET-UP IS FAVORABLE FOR A WINTRY MIX TRANSITIONING TO MAINLY RAIN BY SATURDAY NIGHT. A CONSENSUS OF MDL SOUNDINGS SEEM TO FAVOR ZR/IP AS THE DOMINANT PTYPES. ZR IS OF MOST CONCERN IN THE WESTERN MTNS WHERE ICE ACCUMULATIONS MAY NEAR 0.25 INCHES. THIS IS SUPPORTED BY THE 09Z SREF MEAN AND INTERNAL WWD. THE QPF FOR THIS EVENT /0.50 TO 1.00 INCH/ ALSO POSES THE RISK FOR HIGHER AMTS OF WINTRY PCPN. THE 18Z NAM AND 12Z ECMWF ARE SUGGESTING A POCKET OF SUBFREEZING AIR AT 850MB HOLDS ON LONGER OVER THE ERN ZONES WHICH COULD MAKE FOR A LITTLE MORE SNOW/SLEET. FCST CALLS FOR A GENERAL 0.10 TO 0.25 OF ICE FCST FOR THE INTERIOR CENTRAL MOUNTAINS TAPERING TO JUST A FEW HUNDREDTHS OF AN INCH IN THE LWR SUSQ VLY. SNOW/SLEET AMOUNTS ARE 0.5-1.0 INCH OVER THE NCENTRL AND NERN ZONES BY COULD BE A LITTLE LIGHT AS STUBBORN LLVL COLD AIR DAMMING AND EVAP COOLING SLOW WARMING ALOFT. THE THERMAL GRADIENT ALOFT LOOKS RATHER IMPRESSIVE WITH +10C AT 850MB IN SW PA BY 00Z SUN. THE TAKEAWAY MESSAGE IS TO PREPARE FOR A SIGNIFICANT BUT NOT UNCOMMON WINTER WEATHER EVENT TO AFFECT MUCH OF THE AREA DURING THE DAYLIGHT HOURS WITH PRIMARY IMPACTS RELATED TO TRAVEL. SFC TEMPS WILL SLOWLY CREEP ABOVE FREEZING SATURDAY EVENING/NIGHT WITH LINGERING -ZR CHANGING TO RAIN EXPECTED IN MOST AREAS INTO SUNDAY. PRECIP MAY BECOME LITTLE MORE THAN DRIZZLE ACROSS THE FAR SOUTHERN TIER. STRONG COLD FRONT SHOULD BE CROSSING THE PA/OH BORDER BY 12Z SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... LOOKING AT MAINLY RAIN SHOWERS ON SUNDAY...GIVEN VERY STRONG SW FLOW. 850 MB TEMPS ABOVE 10 DEGREES. IT WILL BE WINDY...BUT NOT WARNING LEVELS. LEFT THUNDER OUT. 500 MB HEIGHT FALLS NOT THAT SIG. THUS NOT CONCERNED ABOUT THUNDER...ESPECIALLY SEVERE. SOME SNOW SHOWERS SUNDAY NIGHT INTO MONDAY...BUT MAINLY ACROSS THE MOUNTAINS. FAST MOVING CLIPPER FOR LATE TUE INTO EARLY WED MORNING. SOME LIGHT SNOW POSSIBLE. MAIN THING FOR WED INTO THU WILL BE A N TO NE FLOW OF MUCH COLDER AIR...SOME CROSS POLAR FLOW. SINCE WINDS WILL BE N TO NE EARLY ON...THE EDGE OF MUCH COLDER AIR CAN WORK TO THE SOUTH AND NOT BE MODIFIED MUCH BY THE LAKES. SOME DIRECTIONAL SHEAR EARLY ON...BUT SIGNIFICANT LAKE EFFECT WILL BE POSSIBLE AS WINDS SHIFT MORE TO THE NW. STILL NOT AS COLD AS WHAT WE SAW IN EARLY JANUARY LAST YEAR. COLDEST AIR REMAINS NORTH OF THE LOWER LAKES WITH SECONDARY HIGH PRESSURE OVER ONTARIO AND QUEBEC. MAIN CHANGE WAS TO EDGE TEMPS DOWN A LITTLE. MORE IN THE WAY OF NORMAL TEMPS WILL WORK BACK IN BY LATE NEXT WEEK...AS WINDS SHIFT MORE TO THE SW. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... CONDITIONS ACROSS THE REGION GENERALLY VFR...EXCEPT FOR SOME LINGERING MVFR CIGS IN THE FAR NORTHWEST INCLUDING KBFD. EXPECT THESE CIGS TO SLOWLY BREAK TO SCATTERED BY 06Z. VFR FOR MUCH OF THE OVERNIGHT...BUT CONDITIONS WILL DETERIORATE RAPIDLY FROM SOUTH TO NORTH BEGINNING AROUND 11Z....AS DEVELOPING LOW PRESSURE OVER THE MIDWEST SPREADS MIXED PRECIPITATION ACROSS THE AIRSPACE. HIGH CONFIDENCE IN REDUCED CONDITIONS TO IFR SATURDAY AND SATURDAY NIGHT AS PRECIPITATION TRANSITIONS TO PLAIN RAIN/DZ/FOG. MILDER AIR WILL SUPPORT SHOWERS AHEAD OF A COLD FRONT ON SUNDAY FOLLOWED BY A COLDER NORTHWEST FLOW SUNDAY NIGHT INTO MONDAY. EXPECT TYPICAL OROGRAPHIC SNOW SHOWERS AND REDUCED VISIBILITIES IN THE MOUNTAINS LATER SUNDAY INTO MONDAY. A CLIPPER SYSTEM WILL BRING A ROUND OF LIGHT SNOW TO THE REGION TUESDAY...FOLLOWED BY MORE SNOW SHOWERS FOR THE MOUNTAINS WEDNESDAY. OUTLOOK... SUN...VARIABLE CONDITIONS...WITH MVFR CIGS AND VSBYS AT TIMES WITH SHOWERS AND COLD FRONTAL PASSAGE. MON...VFR CENTRAL AND SOUTH...WITH AREAS MVFR IN -SHSN WEST AND NORTH. TUE...CHC OF LIGHT SNOW...ESPECIALLY NORTH AND WEST. WED...CHC OF SNOW SHOWERS NORTH AND WEST. WINDY. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 5 PM EST THIS AFTERNOON FOR PAZ004>006-010>012-037-041-042-045-046. WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 5 PM EST THIS AFTERNOON FOR PAZ017>019-024>028-033>036-049>053-056>059- 063>066. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...STEINBUGL LONG TERM...MARTIN AVIATION...JUNG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
914 PM CST SUN JAN 4 2015 .UPDATE... ISSUED AT 904 PM CST SUN JAN 4 2015 00Z MODELS ARE BEGINNING TO TRICKLE IN AND ARE IN FAIRLY GOOD AGREEMENT WITH THE CURRENT FORECAST. HI RESOLUTION SHORT TERM MODELS ARE STILL DIFFERING SOME ON THE TIMING. THE RAP IS A BIT QUICKER THAN THE HRRR...BUT THE LATEST RUN OF THE HRRR IS TRENDING CLOSER TO THE PROGRESSIVE RAP. WITH THE STRONG FORCING AND VERY EFFICIENT ATMOSPHERE FOR PRODUCING DENDRITES...EXPECT CONDITIONS TO RAPIDLY DETERIORATE LATE MONDAY MORNING INTO MONDAY AFTERNOON AS BAND OF SNOW DEVELOPS ACROSS THE AREA. CONSIDERED TRENDING THE WINTER STORM WARNING SLIGHTLY EARLIER...BUT ENOUGH UNCERTAINTY EXISTS RIGHT NOW WITH THE PRECISE TIMING THAT IT IS BEST TO LEAVE THINGS AS IT IS. WITH THE DRY NATURE OF THE SNOW AND THE STRONG WINDS AT BOTH THE ONSET AND THEN AGAIN AT THE END OF THE EVENT...TRAVEL CONDITIONS WILL BE QUITE POOR. THOSE WITH TRAVEL PLANS MONDAY AFTERNOON INTO MONDAY NIGHT SHOULD MAKE ALTERNATIVE PLANS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 258 PM CST SUN JAN 4 2015 TODAY LOOKS LIKE THE CALM BEFORE THE STORM. ALL EYES CONTINUE TO WATCH PROGRESSION OF SHORTWAVE ENERGY JUST NOW BEGINNING TO ENTER THE WESTERN COAST OF BRITISH COLUMBIA. MEANWHILE...AN INITIAL SHORTWAVE ACROSS MONTANA THIS MORNING CONTINUES TO DRIFT SOUTHEAST LATE THIS AFTERNOON. IMPACTS WITH THIS WAVE LOOK TO BE MINIMAL...WITH MUCH OF THE MID-UPR CLOUDS EXPECTED TO STAY SOUTHEAST OF THE REGION. FOR TONIGHT...SURFACE HIGH PRESSURE WILL DROP SOUTHEAST INTO THE AREA. LIGHT WINDS SHOULD SETUP A RATHER COLD NIGHT TONIGHT. OVERNIGHT LOWS WILL FALL BELOW -10 IN MANY LOCATIONS...AND WOULD NOT BE SURPRISED TO SEE A FEW SPOTS DROP TOWARDS -15 OR LOWER. THE LIGHT WINDS WILL PRECLUDE ANY EXTREME WIND CHILL DROP...BUT ANTICIPATING A LIGHT NORTHERLY WIND OVER THE NORTHEASTERN THIRD OF THE CWA TO KEEP WIND CHILL ADVISORY CONDITIONS LIKELY OVERNIGHT. MONDAY WILL START OFF BITTERLY COLD...BUT DECEPTIVELY SUNNY. HI-RES MODELS CONTINUE TO TREND SLIGHTLY FURTHER SOUTH WITH THE TRACK OF THE CLIPPER HEADING INTO THE AREA...RAISING CONFIDENCE IN NUDGING THE HIGHER SNOW TOTALS FURTHER SOUTHWEST. THROUGH THE MORNING...WE WILL BEGIN TO SEE A RAPID INCREASE IN MID-LVL CLOUDS AS MID-LVL WARM ADVECTION BEGINS. A STRONG LOW-LVL FRONTAL CIRCULATION IS EXPECTED TO DEVELOP QUICKLY BY MID-DAY...WITH RAPID TOP-DOWN SATURATION DEVELOPING INTO A FAIRLY BROAD AND ELONGATED AREA OF SNOW ACROSS THE FORECAST AREA. AS ALLUDED TO IN PREVIOUS DISCUSSIONS...THERE IS A HIGH LIKELIHOOD OF AN ENHANCED BAND OF SNOW WITHIN THIS BROAD AREA...WHERE SNOWFALL RATES MAY BE EXTREMELY HIGH. WITH SNOW DRAMATICALLY INCREASING IN THE AFTERNOON AND CONTINUING INTO THE EARLY EVENING...TOTAL SNOWFALL COULD APPROACH 5 TO LOCALLY 8 OR MORE INCHES OF SNOW IN THE HIGHEST CORRIDOR FROM NEAR DE SMET...THROUGH SIOUX FALLS AND FURTHER SOUTHEAST TOWARDS STORM LAKE AND SPENCER. GIVEN DRY AIR ALONG THE NORTHEASTERN FRINGES OF THIS SYSTEM...THE NORTHEASTERN EDGE OF SNOW MAY BE MORE SHARPLY DEFINED THAN INDICATED IN CURRENT GRIDS. SURFACE WINDS WILL COMPLICATE MATTERS DURING THE DAY...AS PERSISTENT SOUTHEAST TO EAST WINDS MAY GUST AS HIGH AS 30 MPH AT TIMES. ONCE THE SURFACE LOW PASSES EARLY IN THE EVENING...WINDS WILL TURN BACK TO THE NORTHWEST WITH THE HIGHEST GUSTS FOCUSED ALONG THE MISSOURI RIVER CHANNEL. AS FAR AS HEADLINES ARE CONCERNED...CONFIDENCE HIGH ENOUGH TO CONVERT MOST OF THE WATCH INTO A WARNING. THE CONCERN WOULD BE IN LYON AND LINCOLN COUNTIES IN MINNESOTA WHERE THE POTENTIAL FOR A TIGHTER NE SNOW GRADIENT MAY SPLIT THE COUNTIES. GIVEN THE POTENTIAL FOR THIS WAVE TO DIG SLIGHTLY FURTHER...WILL LEAVE AND EXPAND THE WATCH SLIGHTLY FURTHER SOUTHWEST TO CORRESPOND WITH THE INCREASE IN SNOW AMOUNTS FORECAST TODAY AND POSSIBILITY OF FURTHER WARNING EXPANSION SOUTHWARD. TRAVEL SHOULD BE ATTEMPTED WITH EXTREME CAUTION MONDAY AFTERNOON INTO MONDAY EVENING...GIVEN THE RAPID DETERIORATION OF CONDITIONS FROM THE FIRST HALF TO THE SECOND HALF OF THE DAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 258 PM CST SUN JAN 4 2015 THE COLD AIR SURGE BEHIND THE SNOW SYSTEM MONDAY NIGHT WILL BE OUTDONE BY A REINFORCING ARCTIC SURGE TUESDAY NIGHT AS A STRONG CANADIAN WAVE DIGS TOWARD THE GREAT LAKES. TUESDAY WILL BE COLD ENOUGH WITH MOSTLY SINGLE DIGIT HIGHS AND SOME CLOUDS LINGERING BETWEEN THE EXITED STORM AND THE APPROACHING MONSTER ARCTIC HIGH. THE SURGE WILL ARRIVE TUESDAY NIGHT WITH WINDS PICKING UP FROM THE RELATIVELY TAME TUESDAY BREEZE. ALONG WITH THIS SURGE WILL COME SOME BLOWING OF THE FRESH SNOW...POSSIBLY ENOUGH FOR ADVISORIES JUST FOR THAT...AND WIND CHILLS LIKELY DIVING BELOW THE WARNING LEVEL...THAT IS 35 TO 45 BELOW...NORTHEAST AT LEAST...BY WEDNESDAY MORNING. WINDS SHOULD THEN DECREASE SLOWLY DURING THE DAY WEDNESDAY AS THE 1060MB HIGH ARRIVES OVER WESTERN SOUTH DAKOTA...BUT ACTUAL HIGH TEMPERATURES WILL BE BELOW ZERO IN MOST OF THE AREA. THE SURGE BY THE WAY SHOULD CLEAR OUT SKIES PRETTY WELL WITH THAT HIGH GETTING CLOSE. A VERY FAST WARMUP SHOULD TAKE PLACE WEDNESDAY NIGHT WITH THE NEXT WAVE AND FRONT COMING IN EARLY THURSDAY. THIS WARMUP WILL BE SO FAST THAT IT WILL GET IN ONLY A LIMITED WAY TO THE SURFACE. IN FACT...THE THURSDAY COLD FRONT WILL BE MORE LIKE AN OCCLUSION AS A LESS BITING COLD AIR PLUNGE ARRIVES. AFTER HIGHS IN THE TEENS TO MID 20S THURSDAY...FRIDAY WILL BRING HIGHS IN THE SINGLE DIGITS RANGING TO SOME TEENS SOUTHWEST...ALL ABOVE ZERO. SATURDAY AND SUNDAY WILL BE BACK INTO THE TEENS TO LOWER 20S FOR HIGHS...BELOW NORMAL BUT NOT AS MUCH AS EARLY THIS WEEK. WILL KEEP OUT MENTION OF ANY LIGHT SNOW FOR WEDNESDAY NIGHT INTO THURSDAY...WITH THE WARMING BEING TOO FAST TO POOL ENOUGH MOISTURE. THERE COULD THEN BE SOME ABOUT FRIDAY OR SATURDAY AS SOME SLOW WARM ADVECTION BEGINS ALOFT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 528 PM CST SUN JAN 4 2015 DIFFICULT TO SEE ON THE IR SATELLITE PICTURE DUE TO HIGH CLOUDS... BUT THERE IS SOME PATCHY MVFR CEILINGS MOVING THROUGH THE KHON AREA. ACCOUNTED FOR THIS ONLY FOR AN HOUR...ALTHOUGH THEY ARE ALREADY GOING SCATTERED SO MAY ELIMINATE THE TEMPO GROUP SHORTLY IF THIS TREND CONTINUES. OTHERWISE THE FORECAST AREA SHOULD BE VFR TONIGHT AND EARLY MONDAY. HOWEVER BY LATE MORNING MONDAY... CONDITIONS WILL DETERIORATE RAPIDLY AS SURFACE LOW PRESSURE DROPS SOUTHEASTWARD FROM EXTREME SOUTHEAST MONTANA TO SOUTH CENTRAL SD THROUGH THE AFTERNOON. A WARM FRONT WILL GENERATE AHEAD OF THE LOW PROVIDING A FOCUS FOR SNOWFALL AFFECTING MUCH OF OUR FORECAST AREA INCLUDING THE THREE TAF SITES OF KHON...KFSD AND KSUX. STRONG DYNAMICS ALSO EXISTS ABOVE THE WARM FRONT IN THE MID AND UPPER LEVELS OF THE ATMOSPHERE...SO EXPECTING WIDESPREAD IFR TO LIFR CONDITIONS MONDAY AFTERNOON. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR SDZ038-053-054-061-066-070-071. WINTER STORM WARNING FROM NOON MONDAY TO MIDNIGHT CST MONDAY NIGHT FOR SDZ039-040-055-056-062-067. WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR SDZ038>040-052>056- 061-062-067. MN...WINTER STORM WARNING FROM NOON MONDAY TO MIDNIGHT CST MONDAY NIGHT FOR MNZ071-072-080-081-089-090-097-098. WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR MNZ071-072-080-081- 089-090-097-098. IA...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR IAZ020-031-032. WINTER STORM WARNING FROM NOON MONDAY TO MIDNIGHT CST MONDAY NIGHT FOR IAZ001>003-012>014-021-022. WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR IAZ001>003-012>014- 021-022-032. NE...NONE. && $$ UPDATE... SHORT TERM... LONG TERM...DUX AVIATION...MJ
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
1150 AM CST SAT JAN 3 2015 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. /53/ && .AVIATION... AFTERNOON FLIGHT CATEGORIES WILL REMAIN PROBLEMATIC ACROSS AREA TERMINALS THANKS TO LOW CIGS. SATELLITE IMAGERY SHOWS A CLEARING LINE NEARING A KAPY-KHBV LINE AT 03/1700 UTC. BASED ON CURRENT E/SE PROGRESSION (AND THE LATEST HRRR DATA)...CIGS SHOULD START LIFTING BY MID-AFTERNOON NEAR A KBKS-KEBG LINE. CIGS MAY NOT IMPROVE ACROSS THE LOWER VALLEY AIRPORTS UNTIL AFTER 04/0000 UTC. SOME PATCHY -DZ WILL BE POSSIBLE THROUGH 04/0000 UTC...MAINLY AT KBRO AND KHRL...BUT LIMITED COVERAGE PRECLUDES MENTION IN THE 1800 UTC TAF PACKAGE. WITH A DRIER AIRMASS EXPECTED TO MOVE INTO THE REGION TONIGHT... CONDITIONS SHOULD LARGELY BE CAVOK AT AREA TERMINALS. WOULD NOT BE SURPRISED TO SEE SOME BR OVERNIGHT GIVEN LIGHT WINDS AND MOIST GROUND CONDITIONS. FORECAST CONFIDENCE ISN`T THAT GREAT...AND...AT LEAST FOR NOW...I PLAN ON LEAVING THIS OUT OF THE LATEST TAF PACKAGE. /53/ && .PREV DISCUSSION... /ISSUED 1059 AM CST SAT JAN 3 2015/ DISCUSSION... UPPER LOW OVER THE TEXAS PANHANDLE CONTINUES TO EJECT INTO THE CENTRAL PLAINS LATE THIS MORNING...AND PUSH THE TROUGH OF LOW PRESSURE IN THE WESTERN GULF EAST. RADAR STILL SHOWS A SMATTERING OF SHOWERS (MAINLY) OVER THE OFFSHORE GULF OF MEXICO WATERS...WITH SOME PATCHY NUSAINCE DRIZZLE IN THE LOW CLOUDS HUGGING THE LOWER VALLEY. MOST OF THE SHOWER ACTIVITY SHOULD REMAIN OFFSHORE THIS AFTERNOON...WITH THE FOCUS FOR DEEPER...MORE ORGANIZED... CONVECTION NORTHEAST OF OUR MARINE AREA. TEMPERATURES WILL AGAIN BE PROBLEMATIC THIS AFTERNOON...THANKS TO WIDESPREAD LOW CLOUDS OVER MOST OF THE REGION. THE CLEARING LINE (SO-TO-SPEAK) WAS LOCATED JUST SOUTH OF A LINE FROM SAN YGNACIO... TO AGUILARES...TO FREER AT 1030 THIS MORNING. EVEN IF THE CLEARING LINE REACHES THE HEBBRONVILLE AND FALFURRIAS AREAS WITHIN THE NEXT HOUR...AFTERNOON HIGHS WILL LIKELY BE COOLER THAN CURRENTLY FORECAST. AS SUCH...SOME ADJUSTMENT HAS BEEN MADE IN THE HOURLY TEMPERATURE GRIDS FOR THIS AFTERNOON. NEW NUMBERS ARE GIVEN BELOW FOR YOUR PERUSAL. ISC GRIDS HAVE BEEN SENT AND SHOULD BE POSTED TO THE INTERNET. UPDATED TEXT PRODUCTS WILL BE COMING SHORTLY. /53/ PREV DISCUSSION... /ISSUED 542 AM CST SAT JAN 3 2015/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE LOW CLOUDS ACROSS MOST OF THE CWA THIS MORNING. CEILINGS WERE NEAR 400FT AT KPIL TO NEAR 2600FT AT KBKS. EXPECT MVFR TO IFR CONDITIONS TO PREVAIL THROUGH 15Z ACROSS THE RIO GRANDE VALLEY BEFORE A 500MB LOW ACROSS SOUTHEAST NEW MEXICO/WEST TEXAS MOVES EASTWARD BRINGING DRIER AIR ALOFT ACROSS SOUTHWEST TX LATE THIS MORNING INTO EARLY THIS AFTERNOON. CEILINGS WILL IMPROVE TO VFR CONDITIONS FROM WEST TO EAST BETWEEN 15Z AND 21Z AS A RESULT. PREV DISCUSSION... /ISSUED 316 AM CST SAT JAN 3 2015/ SHORT TERM.../TODAY THROUGH SUNDAY/...SATELLITE AND RADAR IMAGES CONTINUE TO INDICATE ELEVATED CONVECTION ACROSS EASTERN PORTIONS OF THE STATE THIS MORNING BUT NOT MUCH IN THE WAY OF SHOWERS OR THUNDERSTORMS ACROSS THE RIO GRANDE PLAINS. WARMER TEMPERATURES ALOFT ACROSS NORTHEAST MEXICO WITH SOUTHWEST TO WEST FLOW AT 850MB MAY BE INHIBITING DEVELOPMENT ACROSS SOUTHWEST TEXAS. IN ADDITION...WATER VAPOR SAT IMAGES INDICATE DRIER AIR ALOFT BEGINNING TO MOVE ACROSS PORTIONS OF SOUTHWEST TX AS THE 500MB LOW ACROSS SOUTHERN NEW MEXICO/WEST TX CONTINUES TO MOVE EASTWARD. WITH THAT SAID...WILL CONTINUE TO MENTION A CHANCE OF SHOWERS ACROSS THE COASTAL SECTIONS OF THE CWA THIS MORNING BEFORE DRIER AIR MOVES INTO THE AREA THIS AFTERNOON FROM WEST TO EAST AS THE STATIONARY FRONTAL BOUNDARY OFFSHORE THE LOWER TX COAST MOVES EASTWARD. TEMPERATURES SHOULD FINALLY BEGIN TO WARM ACROSS NORTHERN AND WESTERN PORTIONS OF THE CWA THIS AFTERNOON WHERE SKIES SHOULD BEGIN TO CLEAR. COLDER TEMPS WILL LINGER ACROSS SOUTHEAST PORTIONS OF THE CWA TODAY WHERE CLEARING IS NOT EXPECTED UNTIL TONIGHT. RADIATIONAL COOLING WILL ALLOW TEMPERATURES TO FALL INTO THE 40S ACROSS THE NORTHERN RANCHLANDS TONIGHT. TEMPS WILL WARM INTO THE 60S SUNDAY BEFORE ANOTHER SURGE OF HIGH PRESSURE BRINGS COLD AIR ACROSS THE CENTRAL UNITED STATES SOUTHWARD INTO SOUTH TEXAS SUN AFTERNOON. LONG TERM.../SUNDAY NIGHT THROUGH SATURDAY/...EARLY IN THE LONG TERM PERIOD SOUTH TEXAS WILL BE UNDER THE CONTROL OF A SURFACE HIGH PRESSURE WITH NORTH TO NORTHEAST FLOW ACROSS THE AREA. THIS HIGH WILL BRING ENOUGH DRY AIR BEHIND IT TO PUSH DEEP MOISTURE SOUTHWARD CLEARING THE VALLEY SUNDAY NIGHT INTO MONDAY. A RATHER WEAK CUT OFF LOW DEVELOPS OVER BAJA CA MOVES WHILE RIDGE AMPLIFIES ACROSS THE W COAST. HIGH PRESSURE WILL BUILD ACROSS GULF OF MEXICO RETURNING THE EASTERLY FLOW ACROSS THE CWA THURSDAY AND WEDNESDAY. ABUNDANT MOISTURE IS SHOWN ON BOTH MODELS OVER CENTRAL GULF OF MX SURGING INTO THE CWA ENHANCING SHOWER ACTIVITY AND CLOUDY CONDITIONS. TEMPERATURES MONDAY MORNING WILL BE IN THE 40S WARMING DURING THE DAY INTO THE 50S AND A REPEAT EXPECTED INTO EARLY TUESDAY. AS THE EASTERLY FLOW RETURNS WITH LESS CLOUD COVER THE TEMPERATURES WILL WARM UP INTO THE 60S TUESDAY AFTERNOON. THE RIDGE ACROSS THE WEST REMAINS THERE WEDNESDAY ALLOWING FOR ANOTHER STRONG 1050 HIGH PRESSURE TO SURGE COLD CANADIAN AIR SOUTHWARD WED. THE COLD FRONT WILL MAKE ITS WAY ACROSS THE CWA WEDNESDAY WITH STRONG PRESSURE GRADIENT INCREASING NORTH TO NORTHEAST WINDS. MOISTURE IN THE AREA WILL ENHANCE MORE LIGHT TO MODERATE PRECIPITATION WEDNESDAY INTO THURSDAY. THE COLD AIR MASS ASSOCIATED WITH THIS FRONT WILL LOWER TEMPS INTO THE LOW 40S EARLY THURSDAY AND ONLY REACH THE LOW 50S THURSDAY IN THE AFTERNOON. RIDGE MIGRATES EAST ALLOWING FOR THIS HIGH PRESSURE TO SHIFT EAST. THE NE TO E FLOW RETURNS SURGING GULF MOISTURE INTO THE CWA AND AS A RESULT INCREASING THE PRECIPITATION POTENTIAL INTO THURSDAY NIGHT AND FRIDAY. DURING THIS TIME ON THURSDAY THE CUT OFF LOW OVER BAJA STARTS TO SHIFT EAST WEAKENING AS IT MOVES ACROSS NM. BY FRIDAY...THE WEAK SHORTWAVE WILL ENHANCE MORE SHOWER ACTIVITY FRIDAY INTO SATURDAY WITH THIS WEAK WAVE WITH TEMPERATURES GRADUALLY WARMING INTO THE 60S FRIDAY AND SATURDAY. MARINE...TODAY THROUGH SUNDAY...SEAS WERE NEAR 3 FEET WITH NORTH TO NORTHWEST WINDS NEAR 18 KNOTS AT BUOY020 EARLY THIS MORNING. MODERATE NORTHWEST WINDS WILL PREVAIL ACROSS THE COASTAL WATERS TODAY AS HIGH PRESSURE BUILDS INTO THE WESTERN GULF OF MEXICO AS THE STATIONARY FRONTAL BOUNDARY OFFSHORE THE LOWER TEXAS COAST THIS MORNING MOVES EASTWARD. WINDS WILL VEER TO THE NORTH AND NORTHEAST TONIGHT BEFORE A STRONGER SURGE OF HIGH PRESSURE BUILDS INTO SOUTH TEXAS AND THE WESTERN GULF SUNDAY. WINDS AND SEAS WILL INCREASE ACROSS THE COASTAL WATERS SUN MORNING INTO SUN AFTERNOON AS A RESULT. SMALL CRAFT ADVISORIES WILL BE NEEDED FOR THE OFFSHORE WATERS SUNDAY. SUNDAY NIGHT THROUGH FRIDAY...AFTER THE FRONT EARLY SUNDAY...THE SEAS BEGIN TO INCREASE AS THE GRADIENT STRENGTHENS. THE SEAS BUILDING AND INCREASING WINDS WILL FAVOR FOR SCA CONDITIONS ESPECIALLY SUNDAY NIGHT THROUGH MID MONDAY MORNING. LIGHT TO MODERATE RAIN WILL BE POSSIBLE THROUGH EARLY IN THE WEEK AS SOME LINGERING MOISTURE BEGINS TO INCREASE OVER THE LOWER GULF ZONES. LIGHT TO MODERATE EASTERLY FLOW RETURNS TUESDAY WITH LOW SEAS BUT THE MOISTURE OVER THE AREA WILL INCREASE THE CHANCE OF MORE SHOWERS ACROSS THE LOWER TEXAS GULF WATERS. ANOTHER FRONT ARRIVES WEDNESDAY RETURNING SCA CONDITIONS ACROSS THE GULF WITH MORE POTENTIAL FOR RAIN AND OVERCAST SKIES. HIGH PRESSURE SHIFTS EAST LATE THURSDAY INTO FRIDAY RETURNING NE TO E FLOW OVER THE GULF WITH WEAKER PRESSURE GRADIENT. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV SHORT TERM FORECASTER... BUTTS LONG TERM FORECASTER... DRILLETTE PSU/GRAPHICAST... BIRCHFIELD
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1131 PM CST FRI JAN 2 2015 .AVIATION... STILL EXPECTING MOSTLY IFR/LIFR CEILINGS AND VISIBILITIES ALONG WITH INCREASING RA COVERAGE (AND SOME EMBEDDED SHRA/TSRA) ACROSS MUCH OF THE AREA OVERNIGHT. THERE COULD BE BRIEF PERIODS OF IMPROVED CONDITIONS... BUT SIGNIFICANT IMPROVEMENT SHOULD NOT OCCUR UNTIL LATE TOMORROW MORNING OUT WEST (CLL AREA) AND DURING THE AFTERNOON HOURS TOWARD THE EAST AS THIS STORM SYSTEM MOVES OFF TO THE EAST. 42 && .PREV DISCUSSION... /ISSUED 937 PM CST FRI JAN 2 2015/ UPDATE... WARM FRONT REMAINS DRAPED ALONG THE COAST THIS EVENING FROM JUST SOUTH OF PALACIOS TO GALVESTON TO BEAUMONT. ASIDE FROM A WIND SHIFT THIS BOUNDARY IS ALSO APPARENT DUE TO THE 10 DEGREE DIFFERENCE IN DEWPOINT BETWEEN ANGLETON AND GALVESTON. AREA OF SHOWERS AND THUNDERSTORMS THAT PASSED THROUGH THE METRO AREA EARLIER THIS EVENING CONTINUES TO PUSH OFF TO THE NORTH WITH ONLY ISOLATED SHOWERS ACROSS THE SOUTHERN HALF OF OUR AREA AT THE MOMENT. EXPECTING THIS SLIGHT BREAK IN THE ACTIVITY TO CONTINUE THIS EVENING BEFORE COVERAGE PICKS UP AGAIN AFTER MIDNIGHT AS ANOTHER WEAK DISTURBANCE APPROACHES THE REGION. PRECIP FORECAST LOOKS TO BE IN GOOD SHAPE THIS EVENING AND ONLY CHANGES WERE SOME ADJUSTMENTS TO TEMPERATURES AND DEWPOINTS TO REFLECT THE POSITION OF THE WARM FRONT. 38 PREV DISCUSSION... /ISSUED 345 PM CST FRI JAN 2 2015/ DISCUSSION... A WARM FRONT OVER THE WATERS THIS MORNING HAS CONTINUED TO PUSH NORTH AND HAS STARTED TO MOVE INLAND. THIS HAS ALLOWED DENSE SEA FOG TO START TO MOVE INLAND AS WELL. DUE TO THIS HAVE EXTENDED THE DENSE FOG ADVISORY UNTIL 6 AM TOMORROW MORNING AND HAVE ALSO ADDED BRAZORIA... CHAMBERS...HARRIS... AND LIBERTY COUNTIES. GFS... EURO... AND CANADIAN ARE ALL IN AGREEMENT WITH RAIN CHANCES INCREASING STARTING AFTER MIDNIGHT TONIGHT INTO SATURDAY MORNING. JET DYNAMICS AGAIN LOOK PRETTY GOOD WITH SOUTHEAST TEXAS BEING IN A RRQ AND LFQ. FORECAST SOUNDINGS FOR THE GFS AND NAM BOTH SHOW K INDEX VALUES AROUND 37 EARLY TOMORROW MORNING WITH PWATS RANGING FROM 1.45 TO AROUND 1.60" (AROUND TO JUST UNDER +2 SD FOR THIS TIME OF YEAR). HIGH RES RAP HAS PERFORMED THE BEST TODAY AND DOES NOT HAVE THAT IMPRESSIVE OF RAINFALL TOTALS FOR TOMORROW MORNING WHILE THE NAM AND EURO HAVE AROUND 0.5" TO 1.50" TOTAL FOR THE EVENT. THE STRONG UPPER LIFT IS HARD TO IGNORE AND WILL GO WITH GFS/ EURO CONSENSUS ON RAINFALL TOTALS. THE HIGHEST PRECIP TOTALS DUE APPEAR TO BE TOWARDS PORT AUTHOR THOUGH. THE RAIN WILL MOVE OUT OF THE AREA SATURDAY WITH CLEARING SKIES BEHIND IT. A STRONGER ARCTIC FRONT WILL THEN MOVE THROUGH THE AREA SUNDAY MORNING. AHEAD OF THE FRONT SOME PATCHY FOG CAN BE EXPECTED AS WINDS WEAKEN AND SKIES GO MOSTLY CLEAR. DEWPOINT DEPRESSION FIELD FROM THE NAM SUPPORTS THIS. AT THE SAME TIME AN UPPER LEVEL LOW WILL FORM OVER THE BAJA OF CALIFORNIA AND BEGIN TO RETROGRADE. THE LOW WILL THEN MOVE UNDERNEATH A RIDGE OF HIGH PRESSURE FORMING A REX BLOCK. THE CANADIAN AND EURO ARE AGAIN IN GOOD AGREEMENT HERE. THE GFS CONTINUES TO TREND TOWARDS THE CANADIAN/ EURO SOLUTION. THE EURO THEN BRINGS A MUCH STRONGER FRONT THROUGH THE AREA EARLY WEDNESDAY. THE EURO AND CANADIAN BRING A 1050MB HIGH DOWN WITH A 1043 HIGH SETTLING OVER SAN ANGELO THURSDAY MORNING. THE EURO AND CANADIAN ALMOST LOOK IDENTICAL THURSDAY MORNING. GIVEN THE CONSISTENCY BETWEEN THE EURO AND CANADIAN HAVE TRENDED TEMPS DOWN SLIGHTLY THURSDAY MORNING. 23 MARINE... A WARM FRONT CONTINUES TO ENCROACH ON THE COAST AND SFC DEW PTS OVER THE WATER HAVE WARMED INTO THE LOWER 60S. WATER TEMPS ARE IN THE UPPER 50S AND THIS HAS LED TO SOME SEA FOG. FEEL THE THREAT FOR FOG WILL PERSIST FOR MUCH OF THE NIGHT AND WILL EXTEND THE DENSE FOG ADVISORY OVER THE WATER THROUGH 12Z. SCATTERED SHRA/TSRA WILL BECOME MORE NUMEROUS TONIGHT INTO SATURDAY AS A COLD FRONT APPROACHES THE AREA. CONVECTION WILL PROVIDE SOME MIXING FROM TIME TO TIME BUT FEEL THE OVERALL TREND WILL FAVOR LOW VSBY IN FOG. ALTHOUGH WINDS HAVE DIMINISHED...FEEL TIDE LEVELS WILL REMAIN SLIGHTLY ELEVATED UNTIL A PACIFIC COLD FRONT USHERS IN AN OFFSHORE FLOW ON SATURDAY MORNING. A SECONDARY SURGE OF COLDER AIR ON SUNDAY WILL MOVE OVER THE WARMER GULF WATERS AND THE STRONG CONTRAST IN TEMPS WILL PROVIDE FOR A STRONG THERMAL GRADIENT AND OFFSHORE WIND SPEEDS WILL INCREASE. AN SCA WILL LIKELY BE REQUIRED SUNDAY AND SUNDAY NIGHT. ANOTHER FRONT WILL CROSS THE COASTAL WATERS ON WEDNESDAY WITH ANOTHER SCA LIKELY AT THAT TIME. 43 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 43 58 38 48 29 / 100 50 0 0 0 HOUSTON (IAH) 49 60 42 53 33 / 100 60 0 0 0 GALVESTON (GLS) 59 60 47 53 40 / 90 80 10 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...DENSE FOG ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING ZONES: BRAZORIA...CHAMBERS...GALVESTON...HARRIS...LIBERTY. GM...DENSE FOG ADVISORY UNTIL 6 AM CST SATURDAY FOR THE FOLLOWING ZONES: GALVESTON BAY...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...38 AVIATION/MARINE...42
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1238 AM EST SAT JAN 3 2015 .SYNOPSIS... HIGH PRESSURE SHIFTS FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND NORTHEAST THROUGH THE WEEKEND. A STORM SYSTEM MOVING ACROSS THE SOUTHERN PLAINS SENDS A WARM FRONT NORTHWARD INTO THE REGION BY SATURDAY WITH MAINLY RAIN EXPECTED. A COLD FRONT FOLLOWS FOR LATER SUNDAY INTO SUNDAY NIGHT FOLLOWED BY GUSTY NORTHWEST WINDS AND A SURGE OF COLDER AIR FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... AS OF 1225 AM EST SATURDAY... BEEN SEEING LIGHT RETURNS STARTING TO CREEP INTO THE NC MTNS/FOOTHILLS AND ALSO OVER SE WV SINCE 11 PM. HOWEVER...MOISTURE IS STILL SLOWER IN DEEPENING AND LOOKING AT REGIONAL RADAR AND MESOANALYSIS SHOWING BEST LIFT STILL SOUTH OF US OVER SRN NC. THE LATEST HRRR/LOCAL WRF AND RUC DO SPREAD RAIN FURTHER NORTH OVERNIGHT...SO ADJUSTED POPS DOWN SOME TO ACCOUNT FOR SLOWER ARRIVAL TIME. TEMPS OVERALL RUNNING AT OR ABOVE FREEZING MOST OF THE CWA...THOUGH SOME AREAS IN GREENBRIER/BATH ARE AT OR JUST BELOW 32F. WITH SPOTTY SUB FREEZING TEMPS AND LESS QPF STILL NOT SEEING AMPLE COVERAGE OF FZRA OR SLEET TO WARRANT A HEADLINE. ACTUALLY CUT BACK ON ICE THROUGH 12Z...AS THINK NRN TONGUE OF MOISTURE MOVING ACROSS NRN KY INTO HTS WV WILL STICK FURTHER NORTH WHILE SMALLER AREA OF PRECIP AFFECTS THE MTNS OF SE WV AND ALLEGHANYS. PREVIOUS VALID DISCUSSION... LOW LEVEL WINDS WILL START TO BACK TO SOUTHWEST THEN SOUTH ORIENTATION AS AS UPPER LOW MOVES EAST OUT OF THE SOUTHERN PLAINS...AND A SURFACE LOW BEGINS TO FORM NEAR THE MISSISSIPPI DELTA. A WEDGE PATTERN WILL SET UP OVER THE EASTERN PARTS OF THE REGION THAT WILL INTENSIFY HEADING INTO SATURDAY. MILDER AIR IS EXPECTED TO MOVE INTO THE REGION OVERNIGHT...THUS ALLOWING FOR THE OVERNIGHT LOW TEMPERATURES IN MOST AREAS TO OCCUR DURING THE EVENING...WITH TEMPERATURES STEADY OR SLOWLY RISING THROUGH SUNRISE SATURDAY. LOWS TONIGHT WILL RANGE FROM THE LOW TO MID 30S ACROSS THE MOUNTAINS WITH A MIX OF 30S ACROSS THE PIEDMONT. THE FOOTHILLS OF NC WILL SEE LOWS AROUND 40. HIGHS ON SATURDAY WILL RANGE FROM THE UPPER 30S UNDER THE HEART OF THE LEE SIDE WEDGE...TO THE LOWER 50S OUTSIDE OF THE WEDGE IN AREAS BETWEEN BLUEFIELD WV AND RICHLANDS VA. GUSTY CONDITIONS ARE ALSO EXPECTED TO DEVELOP OVERNIGHT AT THE RIDGE TOPS...WITH THE HIGHEST ELEVATIONS EXPERIENCING GUSTS OF 25 TO 30 MPH BY DAYBREAK. DURING THE DAY SATURDAY...GUSTS WILL INCREASE TO 30 TO 35 MPH AT THE HIGHEST ELEVATIONS. ON SATURDAY...THE BULK OF THE PRECIPITATION WILL BECOME FOCUSED NORTH OF THE AREA ALONG THE FORCING OF A DEVELOPING WARM FRONT NEAR THE MASON-DIXON LINE. MOST OF OUR PRECIPITATION WILL BE ALONG THE CREST OF THE BLUE RIDGE SOUTH OF ROANOKE WITH PATCHY LIGHT RAIN ELSEWHERE. && .SHORT TERM /TONIGHT THROUGH MONDAY/... AS OF 200 PM EST FRIDAY... DURING THE OVERNIGHT HOURS SATURDAY NIGHT/SUNDAY MORNING...GFS/ECMWF/SREF ALL STRENGTHEN THE 850MB JET IN EXCESS OF 50+ KTS IN ADVANCE OF A STRONG COLD FRONT THAT WILL REMAIN WEST OF OUR FORECAST AREA THROUGH 12Z SUNDAY. THIS SHOULD HELP BREAK THE WEDGE...SURGE DEW POINTS UP...AND ALLOW TEMPS TO CLIMB DURING THE OVERNIGHT HOURS. AT THE BEGINNING OF THE SATURDAY NIGHT PERIOD WE MAY SEE A LULL IN THE PRECIP AS WE FALL UNDER A WEAK DRY SLOT...BUT LATER IN THE NIGHT STRONG THETA-E ADVECTION SHOULD HELP GENERATE PRECIP...ESPECIALLY IN THE FAR WEST CLOSER TO THE BEST LOW LEVEL FORCING. GFS/ECMWF/NAM/SREF ARE ALL IN GOOD AGREEMENT THAT THE COLD FRONT EXITS OUR FORECAST AREA BY 00Z MONDAY (7 PM SUNDAY). GFS MOS MOS FORECAST NEAR RECORD/RECORD HIGHS SUNDAY IN THE EAST WHERE 850MB TEMPS WILL BE AOA +12C. WILL CONTINUE THE TREND OF INCREASING HIGHS ON SUNDAY...BUT NOT TO THAT EXTREME. WHILE INSTABILITY PARAMETERS ARE NOT AS IMPRESSIVE AS YESTERDAY...STRONG FORCING WITH THE FRONT COULD STILL GENERATE A FEW RUMBLES OF THUNDER IN THE FAR SOUTHEAST WHERE SPC HAS OUTLOOKED FOR GENERAL THUNDER. BEHIND THE FRONT...STRONG PRESSURE RISES AND 850MB WEST WINDS GREATER THAN 50 KTS WILL BRING STRONG WINDS...ESPECIALLY TO THE MOUNTAINS LATE SUNDAY THROUGH SUNDAY NIGHT. A LOCAL GFS MOS STUDY SUGGESTS FORECAST WINDS AT ROA AND TNB WILL BE HIGH ENOUGH TO EXCEED ADVISORY LEVELS. SIGNIFICANTLY INCREASED WINDS DURING THIS TIME FRAME AND WILL BEEF UP WORDING IN THE HWO FOR THIS THREAT. DESPITE THINNING LOW LEVEL MOISTURE SUNDAY NIGHT AND EARLY MONDAY...COLD AIR ADVECTION SHOULD KEEP LIGHT SNOW/FLURRIES FOR THE WESTERN SLOPES INTO MONDAY MORNING. ACCUMULATIONS IN WESTERN GREENBRIER SHOULD BE 1" OR LESS WITH NO GREAT LAKES CONNECTION. BLUSTERY AND COLD CONDITIONS ARE EXPECTED ON MONDAY WITH WINDS GRADUALLY DIMINISHING AS A LARGE AREA OF HIGH PRESSURE MOVES INTO THE EASTERN OHIO VALLEY BY 00Z TUESDAY (7 PM MONDAY). WENT BELOW GUIDANCE VALUES FOR HIGHS ON MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 300 PM EST FRIDAY... VERY COLD AND WINDY FOR MOST OF THE UPCOMING WEEK. MODELS ARE CONSISTENT IN PROJECTING THE EXTENDED PERIOD TO BE DOMINATED BY A PERSISTENT CUTOFF LOW DEVELOPING OVER THE SOUTHWEST US/BAJA PENINSULA TOPPED BY A DECENT AMPLITUDE RIDGE OVER THE PACIFIC NW...WITH NORTHERN AND SOUTHERN STREAM ENERGY COMBINING TO KEEP THE EASTERN US UNDER THE INFLUENCE OF A BROAD TROF. AS WE HEAD TOWARD THE END OF NEXT WEEK...THE PATTERN WILL BE SHIFTING MORE TO A ZONAL FLOW REGIME WITH THE CUTOFF LOW OVER THE SOUTHWEST US OPENING UP WHILE THE EASTERN TROF LIFTS NORTHEASTWARD. TUESDAY WILL START OFF WITH HIGH PRESSURE PUSHING OFF TO OUR EAST AS AN ALBERTA CLIPPER ZIPS BY WELL TO OUR NORTH AND SWINGS A COLD FRONT THROUGH LATE ON TUESDAY. THIS COLD FRONT WILL OPEN THE FREEZER DOOR AND ALLOW ARCTIC AIR TO POUR INTO THE REGION ON STRONG NORTHWEST WINDS STARTING TUESDAY NIGHT...SETTING THE STAGE FOR VERY COLD TEMPERATURES FOR THE MIDDLE OF THE WORKWEEK. TEMPERATURES WILL BE PUSHING 20 DEGREES BELOW NORMAL ON BOTH WEDNESDAY AND THURSDAY...AND THE HOWLING NORTHWEST WIND WILL BRING WIND CHILL VALUES INTO THE SINGLE DIGITS TO BELOW ZERO FROM WEDNESDAY MORNING THROUGH FRIDAY MORNING WITH THE HARSHEST CONDITIONS EXPECTED WEST OF THE BLUE RIDGE. CONDITIONS WILL MODERATE...THOUGH REMAIN BELOW NORMAL...BY FRIDAY AND INTO THE WEEKEND AS THE CORE OF THE COLD AIR PUSHES THROUGH. MOISTURE WILL BE QUITE LIMITED WITH THE COLD AIR BUT IT WILL NOT TAKE MUCH TO SQUEEZE OUT SOME UPSLOPE NORTHWEST FLOW SNOW SHOWERS WEST OF THE BLUE RIDGE. CURRENT INDICATIONS ARE THAT THE FAR WESTERN SLOPES MAY SEE ENOUGH PERSISTENT SNOW SHOWERS FOR SOME LIGHT AND DRY WINDBLOWN ACCUMULATIONS TUESDAY NIGHT INTO WEDNESDAY. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 1140 PM EST FRIDAY... CEILINGS HAD BEEN LOWERING DURING THE EVENING AND WERE MVFR OVER THE MOUNTAINS. MVFR CEILINGS WILL EXPAND INTO KLWB/KDAN/KLYH BY 09Z/4AM. HAVE AGAIN SLOWED DOWN THE ARRIVAL TIME OF THE RAIN FOR TONIGHT UNTIL AFTER 08Z/2AM...BASED ON THE LATEST RADAR TRENDS AND THE HRRR GUIDANCE. SURFACE BASED WEDGE DEVELOPS LATE TONIGHT ON THE EASTERN SLOPES OF THE APPALACHIANS. ABOVE THIS WEDGE...LOW LEVEL WINDS SHIFT TO THE SOUTH WITH WIND SPEEDS INCREASING TO AROUND 45 KNOTS BY 12Z/7AM OVER THE MOUNTAINS. THIS INCREASINGLY STRONG SOUTH WIND WILL RESULT IN STRONG ISENTROPIC LIFT AND WIDESPREAD LIGHT RAIN. HAVE ADDED EXPANDED THE LLWS INTO LATE SATURDAY. HIGH CONFIDENCE THAT CEILINGS WILL LOWER TO IFR AS THE RAIN BEGINS AND VISIBILITIES WILL HOLD IN THE MVFR RANGE. A MAJORITY OF THE RAIN WILL MOVE NORTH OUT OF THE REGION BY SATURDAY AFTERNOON. HOWEVER...CEILINGS AND VISIBILITIES WILL BE VERY SLOW TO IMPROVE. ONLY MODERATE CONFIDENCE THAT CEILINGS WILL LIFT BACK ABOVE 1500FT. KBLF MAY BREAK OUT OF THE WEDGE SATURDAY NIGHT WITH WINDS BECOMING GUSTY FROM THE SOUTH TO SOUTHWEST. OTHER TAF SITES WILL LOWER TO IFR AFTER SUNSET. STRONG COLD FRONTAL PASSAGE ON SUNDAY. VERY GUSTY WINDS BEHIND THE FRONT. CONDITIONS IMPROVE TO VFR ACROSS ALL BUT THE FAR WESTERN PARTS OF THE REGION. MONDAY INTO TUESDAY...PRIMARILY VFR CONDITIONS ACROSS THE AREA WITH THE RETURN OF SURFACE HIGH PRESSURE...BUT TIGHT GRADIENT AT 850 MB WILL HELP MAINTAIN GUSTY CONDITIONS. CLIPPER SYSTEM PASSES MAINLY NORTH OF THE REGION TUESDAY AFTERNOON. EXPECT REINFORCING PUNCH OF COLDER AIR AND CONTINUED STRONG NORTHWEST WINDS THROUGH THURSDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PH NEAR TERM...AMS/DS/WP SHORT TERM...PH LONG TERM...MBS AVIATION...AMS/DS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1145 PM EST FRI JAN 2 2015 .SYNOPSIS... HIGH PRESSURE SHIFTS FROM THE OHIO VALLEY INTO THE MID ATLANTIC AND NORTHEAST THROUGH THE WEEKEND. A STORM SYSTEM MOVING ACROSS THE SOUTHERN PLAINS SENDS A WARM FRONT NORTHWARD INTO THE REGION BY SATURDAY WITH MAINLY RAIN EXPECTED. A COLD FRONT FOLLOWS FOR LATER SUNDAY INTO SUNDAY NIGHT FOLLOWED BY GUSTY NORTHWEST WINDS AND A SURGE OF COLDER AIR FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... AS OF 855 PM EST FRIDAY... SURFACE HIGH PRESSURE WAS CENTERED OVER SOUTHERN MARYLAND. PREVAILING 85H WINDS WERE STILL FROM THE WEST BUT SPEEDS WERE DIMINISHING AND WERE LESS THAN 25 KNOTS ON THE 00Z BLACKSBURG SOUNDING. LOW LEVEL WINDS WILL START TO BACK TO SOUTHWEST THEN SOUTH ORIENTATION AS AS UPPER LOW MOVES EAST OUT OF THE SOUTHERN PLAINS...AND A SURFACE LOW BEGINS TO FORM NEAR THE MISSISSIPPI DELTA. A WEDGE PATTERN WILL SET UP OVER THE EASTERN PARTS OF THE REGION THAT WILL INTENSIFY HEADING INTO SATURDAY. HAVE ADJUSTED THE ARRIVAL TIME OF THE PRECIPITATION. LOCAL WRF SUGGESTED RAIN AS EARLY AS 10PM...BUT HRRR AND RAP GUIDANCE HELD OFF A BULK OF THE PRECIPITATION UNTIL MIDNIGHT. A FEW POCKETS OF SLEET ARE POSSIBLE ON THE LEADING EDGE OF THE PRECIPITATION... GENERALLY ALONG AND NORTH OF I-64 IN WV AND VA. A LARGE EXPANSE OF RAIN WILL SPREAD ACROSS THE AREA FROM SOUTHWEST TO NORTHEAST BEFORE SUNRISE. MILDER AIR IS EXPECTED TO MOVE INTO THE REGION OVERNIGHT...THUS ALLOWING FOR THE OVERNIGHT LOW TEMPERATURES IN MOST AREAS TO OCCUR DURING THE EVENING...WITH TEMPERATURES STEADY OR SLOWLY RISING THROUGH SUNRISE SATURDAY. LOWS TONIGHT WILL RANGE FROM THE LOW TO MID 30S ACROSS THE MOUNTAINS WITH A MIX OF 30S ACROSS THE PIEDMONT. THE FOOTHILLS OF NC WILL SEE LOWS AROUND 40. HIGHS ON SATURDAY WILL RANGE FROM THE UPPER 30S UNDER THE HEART OF THE LEE SIDE WEDGE...TO THE LOWER 50S OUTSIDE OF THE WEDGE IN AREAS BETWEEN BLUEFIELD WV AND RICHLANDS VA. GUSTY CONDITIONS ARE ALSO EXPECTED TO DEVELOP OVERNIGHT AT THE RIDGE TOPS...WITH THE HIGHEST ELEVATIONS EXPERIENCING GUSTS OF 25 TO 30 MPH BY DAYBREAK. DURING THE DAY SATURDAY...GUSTS WILL INCREASE TO 30 TO 35 MPH AT THE HIGHEST ELEVATIONS. ON SATURDAY...THE BULK OF THE PRECIPITATION WILL BECOME FOCUSED NORTH OF THE AREA ALONG THE FORCING OF A DEVELOPING WARM FRONT NEAR THE MASON-DIXON LINE. MOST OF OUR PRECIPITATION WILL BE ALONG THE CREST OF THE BLUE RIDGE SOUTH OF ROANOKE WITH PATCHY LIGHT RAIN ELSEWHERE. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... AS OF 200 PM EST FRIDAY... DURING THE OVERNIGHT HOURS SATURDAY NIGHT/SUNDAY MORNING...GFS/ECMWF/SREF ALL STRENGTHEN THE 850MB JET IN EXCESS OF 50+ KTS IN ADVANCE OF A STRONG COLD FRONT THAT WILL REMAIN WEST OF OUR FORECAST AREA THROUGH 12Z SUNDAY. THIS SHOULD HELP BREAK THE WEDGE...SURGE DEW POINTS UP...AND ALLOW TEMPS TO CLIMB DURING THE OVERNIGHT HOURS. AT THE BEGINNING OF THE SATURDAY NIGHT PERIOD WE MAY SEE A LULL IN THE PRECIP AS WE FALL UNDER A WEAK DRY SLOT...BUT LATER IN THE NIGHT STRONG THETA-E ADVECTION SHOULD HELP GENERATE PRECIP...ESPECIALLY IN THE FAR WEST CLOSER TO THE BEST LOW LEVEL FORCING. GFS/ECMWF/NAM/SREF ARE ALL IN GOOD AGREEMENT THAT THE COLD FRONT EXITS OUR FORECAST AREA BY 00Z MONDAY (7 PM SUNDAY). GFS MOS MOS FORECAST NEAR RECORD/RECORD HIGHS SUNDAY IN THE EAST WHERE 850MB TEMPS WILL BE AOA +12C. WILL CONTINUE THE TREND OF INCREASING HIGHS ON SUNDAY...BUT NOT TO THAT EXTREME. WHILE INSTABILITY PARAMETERS ARE NOT AS IMPRESSIVE AS YESTERDAY...STRONG FORCING WITH THE FRONT COULD STILL GENERATE A FEW RUMBLES OF THUNDER IN THE FAR SOUTHEAST WHERE SPC HAS OUTLOOKED FOR GENERAL THUNDER. BEHIND THE FRONT...STRONG PRESSURE RISES AND 850MB WEST WINDS GREATER THAN 50 KTS WILL BRING STRONG WINDS...ESPECIALLY TO THE MOUNTAINS LATE SUNDAY THROUGH SUNDAY NIGHT. A LOCAL GFS MOS STUDY SUGGESTS FORECAST WINDS AT ROA AND TNB WILL BE HIGH ENOUGH TO EXCEED ADVISORY LEVELS. SIGNIFICANTLY INCREASED WINDS DURING THIS TIME FRAME AND WILL BEEF UP WORDING IN THE HWO FOR THIS THREAT. DESPITE THINNING LOW LEVEL MOISTURE SUNDAY NIGHT AND EARLY MONDAY...COLD AIR ADVECTION SHOULD KEEP LIGHT SNOW/FLURRIES FOR THE WESTERN SLOPES INTO MONDAY MORNING. ACCUMULATIONS IN WESTERN GREENBRIER SHOULD BE 1" OR LESS WITH NO GREAT LAKES CONNECTION. BLUSTERY AND COLD CONDITIONS ARE EXPECTED ON MONDAY WITH WINDS GRADUALLY DIMINISHING AS A LARGE AREA OF HIGH PRESSURE MOVES INTO THE EASTERN OHIO VALLEY BY 00Z TUESDAY (7 PM MONDAY). WENT BELOW GUIDANCE VALUES FOR HIGHS ON MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... AS OF 300 PM EST FRIDAY... VERY COLD AND WINDY FOR MOST OF THE UPCOMING WEEK. MODELS ARE CONSISTENT IN PROJECTING THE EXTENDED PERIOD TO BE DOMINATED BY A PERSISTENT CUTOFF LOW DEVELOPING OVER THE SOUTHWEST US/BAJA PENINSULA TOPPED BY A DECENT AMPLITUDE RIDGE OVER THE PACIFIC NW...WITH NORTHERN AND SOUTHERN STREAM ENERGY COMBINING TO KEEP THE EASTERN US UNDER THE INFLUENCE OF A BROAD TROF. AS WE HEAD TOWARD THE END OF NEXT WEEK...THE PATTERN WILL BE SHIFTING MORE TO A ZONAL FLOW REGIME WITH THE CUTOFF LOW OVER THE SOUTHWEST US OPENING UP WHILE THE EASTERN TROF LIFTS NORTHEASTWARD. TUESDAY WILL START OFF WITH HIGH PRESSURE PUSHING OFF TO OUR EAST AS AN ALBERTA CLIPPER ZIPS BY WELL TO OUR NORTH AND SWINGS A COLD FRONT THROUGH LATE ON TUESDAY. THIS COLD FRONT WILL OPEN THE FREEZER DOOR AND ALLOW ARCTIC AIR TO POUR INTO THE REGION ON STRONG NORTHWEST WINDS STARTING TUESDAY NIGHT...SETTING THE STAGE FOR VERY COLD TEMPERATURES FOR THE MIDDLE OF THE WORKWEEK. TEMPERATURES WILL BE PUSHING 20 DEGREES BELOW NORMAL ON BOTH WEDNESDAY AND THURSDAY...AND THE HOWLING NORTHWEST WIND WILL BRING WIND CHILL VALUES INTO THE SINGLE DIGITS TO BELOW ZERO FROM WEDNESDAY MORNING THROUGH FRIDAY MORNING WITH THE HARSHEST CONDITIONS EXPECTED WEST OF THE BLUE RIDGE. CONDITIONS WILL MODERATE...THOUGH REMAIN BELOW NORMAL...BY FRIDAY AND INTO THE WEEKEND AS THE CORE OF THE COLD AIR PUSHES THROUGH. MOISTURE WILL BE QUITE LIMITED WITH THE COLD AIR BUT IT WILL NOT TAKE MUCH TO SQUEEZE OUT SOME UPSLOPE NORTHWEST FLOW SNOW SHOWERS WEST OF THE BLUE RIDGE. CURRENT INDICATIONS ARE THAT THE FAR WESTERN SLOPES MAY SEE ENOUGH PERSISTENT SNOW SHOWERS FOR SOME LIGHT AND DRY WINDBLOWN ACCUMULATIONS TUESDAY NIGHT INTO WEDNESDAY. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 1140 PM EST FRIDAY... CEILINGS HAD BEEN LOWERING DURING THE EVENING AND WERE MVFR OVER THE MOUNTAINS. MVFR CEILINGS WILL EXPAND INTO KLWB/KDAN/KLYH BY 09Z/4AM. HAVE AGAIN SLOWED DOWN THE ARRIVAL TIME OF THE RAIN FOR TONIGHT UNTIL AFTER 08Z/2AM...BASED ON THE LATEST RADAR TRENDS AND THE HRRR GUIDANCE. SURFACE BASED WEDGE DEVELOPS LATE TONIGHT ON THE EASTERN SLOPES OF THE APPALACHIANS. ABOVE THIS WEDGE...LOW LEVEL WINDS SHIFT TO THE SOUTH WITH WIND SPEEDS INCREASING TO AROUND 45 KNOTS BY 12Z/7AM OVER THE MOUNTAINS. THIS INCREASINGLY STRONG SOUTH WIND WILL RESULT IN STRONG ISENTROPIC LIFT AND WIDESPREAD LIGHT RAIN. HAVE ADDED EXPANDED THE LLWS INTO LATE SATURDAY. HIGH CONFIDENCE THAT CEILINGS WILL LOWER TO IFR AS THE RAIN BEGINS AND VISIBILITIES WILL HOLD IN THE MVFR RANGE. A MAJORITY OF THE RAIN WILL MOVE NORTH OUT OF THE REGION BY SATURDAY AFTERNOON. HOWEVER...CEILINGS AND VISIBILITIES WILL BE VERY SLOW TO IMPROVE. ONLY MODERATE CONFIDENCE THAT CEILINGS WILL LIFT BACK ABOVE 1500FT. KBLF MAY BREAK OUT OF THE WEDGE SATURDAY NIGHT WITH WINDS BECOMING GUSTY FROM THE SOUTH TO SOUTHWEST. OTHER TAF SITES WILL LOWER TO IFR AFTER SUNSET. STRONG COLD FRONTAL PASSAGE ON SUNDAY. VERY GUSTY WINDS BEHIND THE FRONT. CONDITIONS IMPROVE TO VFR ACROSS ALL BUT THE FAR WESTERN PARTS OF THE REGION. MONDAY INTO TUESDAY...PRIMARILY VFR CONDITIONS ACROSS THE AREA WITH THE RETURN OF SURFACE HIGH PRESSURE...BUT TIGHT GRADIENT AT 850 MB WILL HELP MAINTAIN GUSTY CONDITIONS. CLIPPER SYSTEM PASSES MAINLY NORTH OF THE REGION TUESDAY AFTERNOON. EXPECT REINFORCING PUNCH OF COLDER AIR AND CONTINUED STRONG NORTHWEST WINDS THROUGH THURSDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...PH NEAR TERM...AMS/DS SHORT TERM...PH LONG TERM...MBS AVIATION...AMS/DS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 AM CST SAT JAN 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 311 AM CST SAT JAN 3 2015 CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED STRONG SHORTWAVES OVER WEST CENTRAL ALBERTA...EASTERN WASHINGTON STATE...NORTH CENTRAL MONTANA AND OVER THE FORECAST AREA. ALSO AN UPPER LOW WAS PRESENT OVER NEW MEXICO. MOISTURE HAS BEEN STREAMING NORTHWARD TOWARDS THE FORECAST AREA...DUE TO A SOUTHWARD PULL AHEAD OF BOTH THE UPPER LOW AND THE STRONG SHORTWAVE OVER THE AREA. PRECIPITABLE WATER PER GOES ANALYSIS HAS CLIMBED TO 0.5 INCH OVER SOUTHERN WI...AND 1 INCH ALONG I-70 IN MO AND IL. THIS MOISTURE...COMBINED WITH ISENTROPIC LIFT AND DPVA FORCING AHEAD OF THE SHORTWAVE OVER THE FORECAST AREA...HAS RESULTED IN SNOW ACROSS THE SOUTHEAST HALF OR SO OF THE FORECAST AREA. THE SNOW HAS NOW PUSHED INTO MAINLY WI...WITH SUBSIDENCE AND DRYING WORKING IN FROM THE WEST BEHIND THE SHORTWAVE. MEANWHILE...FARTHER WEST...A SURFACE LOW HAS DEVELOPED NEAR BISMARCK ND DOWNSTREAM OF THE MONTANA SHORTWAVE. 925MB TEMPS AHEAD OF THE LOW ARE GENERALLY 0 TO -6C ACROSS MUCH OF THE DAKOTAS EASTWARD INTO WI. HOWEVER...-20C TO -30C READINGS WERE LURKING TO THE NORTH ACROSS MUCH OF SOUTHERN CANADA. NORTHERLY WINDS BEHIND THE LOW HAS BEGUN BRINGING THIS COLD AIR SOUTH WITH READINGS OVER NORTHERN NORTH DAKOTA NOW IN THE SINGLE DIGITS BELOW ZERO. TODAY CONTINUES TO LOOK MUCH QUIETER ON THE PRECIPITATION SIDE OF THINGS...RESULTING MOSTLY FROM DECENT SUBSIDENCE AND DRYING OCCURRING IN THE WAKE OF THE SHORTWAVE CURRENTLY CROSSING THE FORECAST AREA. ANY LINGERING SNOW OVER WI SHOULD PUSH OFF TO THE EAST OF THE AREA BY 15Z. ALTHOUGH WE DO LOSE ICE IN THE CLOUDS WITH THE PASSAGE OF THE SHORTWAVE...WE ALSO LOSE THE LIFT...SO THE POTENTIAL FOR FREEZING DRIZZLE IS FURTHER REDUCED. MOST 03.00Z GUIDANCE IS NOW MOSTLY DRY FOR THE FORECAST AREA TODAY AND HAVE FOLLOWED SUIT. 925MB TEMPS STAY RELATIVELY MILD TODAY...-2 TO -4C. IF WE WERE SUNNY TODAY...HIGHS COULD POP INTO THE 40S OVER SNOW FREE AREAS. HOWEVER...A SOUTHERLY FLOW LOOKS TO ADVECT IN LOW CLOUDS FROM MO AND IL THROUGH THE FORECAST AREA...WHICH GET TRAPPED UNDER THE SUBSIDENCE INVERSION. IN FACT...CANNOT RULE OUT SOME FOG THIS MORNING OVER THE HIGHER TERRAIN. THESE CLOUDS SHOULD KEEP HIGHS IN THE UPPER 20S TO MID 30S...COLDEST OVER SNOW PACK LOCATIONS. NOW FOR TONIGHT...A LOT MORE IS GOING ON. 1. SNOW LOOKS LIKELY. WE SHOULD BEGIN TO SEE A SNOW BAND SET UP THIS AFTERNOON FROM CENTRAL NEBRASKA INTO NORTHEAST MN. THIS BAND... ASSOCIATED WITH MID LEVEL FRONTOGENESIS AND DPVA DOWNSTREAM OF THE CURRENT MONTANA SHORTWAVE TRACKING EAST...LOOKS TO MOVE INTO THE NORTHWEST HALF OF THE FORECAST AREA DURING THE EVENING...THEN MARCH EAST THROUGH THE REST OF THE FORECAST AREA OVERNIGHT. MODELS ARE IN PRETTY GOOD AGREEMENT IN PRODUCING A TOTAL OF 0.10-0.15 INCHES OF QPF WITH THE BAND...WHICH SEEMS REASONABLE WHEN LOOKING AT THE FORCING AND 0.3-0.4 INCHES OF PRECIPITABLE WATER. WITH SNOW RATIOS OF 15-18 TO 1 RANGE IN THE BAND...DUE TO COLDER AIR FLOWING IN ALLOWING FOR UPWARDS OF 100MB OF EFFECTIVE DENDRITIC GROWTH...A SOLID 1 TO 2 INCHES SEEMS REASONABLE WITH A 3 INCH AMOUNT POSSIBLE. 2. NORTHWEST WINDS ARE GOING TO INCREASE THROUGH THE NIGHT. THIS IN RESPONSE TO THE UPPER LOW EJECTING OUT OF NEW MEXICO AND PHASING WITH THE SHORTWAVE COMING THROUGH THE FORECAST AREA TONIGHT... RESULTING IN A DEEPENING SURFACE LOW LIFTING INTO THE EASTERN GREAT LAKES. 925MB WINDS INCREASE TO 35-40 KT BY 12Z SUNDAY...WHICH WITH PRESSURES RISING RAPIDLY AS THOSE WINDS DRIVE IN COLDER AIR...A GOOD AMOUNT OF THIS WIND SHOULD MIX DOWN. 20-25 KT WINDS FROM MAV GUIDANCE OVER THE HIGHER TERRAIN OF SOUTHEAST MN/NORTHEAST IA SEEMS REASONABLE...WITH GUSTS OF 30-35 KT. GIVEN THE FLUFFIER SNOW TONIGHT...SOME BLOWING AND DRIFTING IS LIKELY WITH THESE WINDS COMING THROUGH. 3. TEMPERATURES AND WIND CHILLS PLUMMETING OVERNIGHT. 925MB TEMPS TANK FROM THE -2 TO -4C AT 00Z TO -10 TO -20C BY 12Z...COLDEST NORTHWEST. THIS SHOULD DROP TEMPERATURES INTO THE SINGLE DIGITS AND TEENS...AND EVEN BELOW ZERO IN SOME OF SOUTHEAST MN BY SUNRISE. WIND CHILLS COULD BE APPROACHING ADVISORY CRITERIA BY 12Z SUNDAY IN PORTIONS OF SOUTHEAST MN. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE WESTERN PORTIONS OF SOUTHEAST MN AND NORTHEAST IA...FROM 06-12Z SUNDAY...TO HANDLE THE NEAR ADVISORY WINDS...FALLING SNOW...WIND CHILLS APPROACHING ADVISORY CRITERIA AND BLOWING/DRIFTING SNOW. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 311 AM CST SAT JAN 3 2015 MAIN LONG TERM FOCUSES ARE ON ARCTIC AIR AND A POSSIBLE ACCUMULATING FLUFFY SNOW EVENT FOR MONDAY NIGHT. THE POOL OF ARCTIC AIR SITUATED CURRENTLY ACROSS MUCH OF SOUTHERN CANADA LOOKS TO INVADE THE REGION SUNDAY AND SUNDAY NIGHT...THANKS TO THE SHORTWAVE OVER WEST CENTRAL ALBERTA DIGGING INTO THE REGION. 925MB TEMPS PLUMMET TO -20 TO -25C BY 00Z MONDAY ON A BRISK NORTHWEST WIND...AND FURTHER LOWERING TO -24 TO -28C BY 12Z MONDAY. TEMPERATURES THAT BEGAN FALLING TONIGHT WILL CONTINUE TO DO SO THROUGH THE DAY SUNDAY AND INTO SUNDAY NIGHT. COMBINED WITH THE BRISK NORTHWEST WIND...WIND CHILL ADVISORIES AND POSSIBLY A FEW WARNINGS ARE GOING TO BE NECESSARY. THE ARCTIC AIR MODIFIES SOMEWHAT ON MONDAY WITH 925MB TEMPS CLIMBING TO -18 TO -22C BY 00Z...ENOUGH THAT WIND CHILL HAZARDS SHOULD BE ALLOWED TO END BY 20Z. ON MONDAY NIGHT...A FAST MOVING BUT POTENT SHORTWAVE IS PROGGED TO AFFECT THE REGION. GOOD MODEL CONSENSUS EXISTS FOR STRONG MID LEVEL FRONTOGENESIS WITH DPVA ENHANCEMENT AND UPPER LEVEL DIVERGENCE TO ACCOMPANY THE SHORTWAVE. QPF FORECASTS ARE IN THE 0.25-0.4 INCH RANGE...WITH UPWARDS OF 200 MB OF EFFECTIVE DENDRITIC SNOW GROWTH. THIS WOULD MEAN EASILY 20 TO 1 RATIOS...QUITE FLUFFY SNOW...AND ACCUMULATIONS IN THE 4 TO 8 INCH RANGE. HOWEVER...PLACEMENT OF THE BAND IS BECOMING A SERIOUS ISSUE AS THERE HAS BEEN A TREND FOR THE SHORTWAVE TO TRACK FARTHER SOUTHWEST THROUGH IOWA IN THE 03.00Z GFS/CANADIAN/ECMWF. THIS TAKES THE HEAVIER SNOW FARTHER SOUTH. SO ITS HARD TO SAY RIGHT NOW EXACTLY HOW MUCH SNOW WE WILL SEE. AT THE MOMENT HAVE 2 TO 5 INCHES...HIGHEST SOUTH OF I-90. EXPECT THESE AMOUNTS TO CHANGE DUE TO BAND PLACEMENT AND INTENSITY. THE FARTHER SOUTHWEST TREND HAS RESULTED IN LOWERED PRECIPITATION CHANCES NORTH OF I-94. PRECIPITATION SHOULD BE OUT OF THE AREA FOR TUESDAY...WITH MORE ARCTIC AIR BEGINNING TO PLUNGE INTO THE REGION IN THE WAKE OF THE SYSTEM...ESPECIALLY TUESDAY NIGHT. 925MB TEMPS TANK FROM -10 TO -16C AT 12Z TO -16 TO -20C BY 00Z WEDNESDAY AND TO -25 TO -30C BY 12Z WEDNESDAY. 925MB WINDS ALSO PROGGED IN THE 35-45 KT RANGE. LUCKILY THE SOUNDING PROFILE MAY END UP BEING ISOTHERMAL TO HELP LIMIT MIXING OF THESE STRONGER WINDS...BUT ITS GOING TO BE BRISK NONETHELESS. MORE WIND CHILL ADVISORIES AND WARNINGS ARE LIKELY FOR TUESDAY NIGHT INTO WEDNESDAY. ADDITIONALLY...THE WIND WILL HELP BLOW THE RECENT FLUFFY SNOW AROUND SO ADDED SOME BLOWING SNOW. BRIEF UPPER RIDGING DROPS DOWN OVER THE FORECAST AREA WEDNESDAY NIGHT INTO THURSDAY...BRINGING SOMEWHAT WARMER AIR INTO THE FORECAST AREA. HOWEVER...COMBINATION OF THE WINDS AND LINGERING ARCTIC AIR LIKELY MEAN A CONTINUATION OF WIND CHILL HAZARDS INTO THURSDAY MORNING. RIGHT NOW HAVE THURSDAY DRY...BUT THE WARM ADVECTION MAY BE ENOUGH TO PRODUCE SOME LIGHT SNOW AND LATER FORECASTS COULD HAVE TO INTRODUCE PRECIPITATION CHANCES. ANOTHER ARCTIC SURGE LOOKS POISED TO FOLLOW FOR THURSDAY NIGHT THROUGH FRIDAY...NOT AS INTENSE AS EARLIER ONES THIS WEEK BUT STRONG ENOUGH TO POSSIBLY NEED A FEW MORE WIND CHILL ADVISORIES. FINALLY...LOOKING AHEAD...THERE IS SIGNAL SHOWING UP TO BREAK OUT OF THE ARCTIC REGIME FOR NEXT WEEKEND. IN FACT...THERE IS SIGNAL IN BOTH THE CFS AND ECMWF TO EVEN GO BACK ABOVE NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1100 AM CST SAT JAN 3 2015 BRIEF BREAK FROM THE LOW CLOUDS THIS MORNING...BUT IFR/MVFR QUICKLY ADVANCING IN FROM THE SOUTH. SOME VSBY RESTRICTIONS WITH THIS BATCH OF CLOUDS. SNOW MOVES IN TONIGHT...WITH 1 TO 2 INCHES OF ACCUMULATION. SUB 1SM VSBYS AND CIGS UNDER 1 KFT SHOULD ACCOMPANY THE MAIN SNOW BAND. IN ADDITION...WINDS ARE GOING TO BECOME STRONG AND GUSTY...SUSTAINED 20 KTS WITH 30+ GUSTS AT KRST. THIS WILL BLOW THE FALLEN SNOW...AND SHOULD KEEP VSBYS AT LEAST IN THE MVFR CATEGORY AT KRST THROUGH SUNDAY MORNING - AFTER THE SNOW STOPS. RH FIELDS SUGGEST A BREAK FROM THE LOW CIGS LATE MORNING...BUT A BAND OF STRATUS COULD MOVE BACK IN FOR A FEW HOURS SUN AFTERNOON. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY FOR MNZ086-087-094-095. IA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY FOR IAZ008>010-018-019-029. && $$ SHORT TERM...AJ LONG TERM....AJ AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
529 AM CST SAT JAN 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 311 AM CST SAT JAN 3 2015 CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED STRONG SHORTWAVES OVER WEST CENTRAL ALBERTA...EASTERN WASHINGTON STATE...NORTH CENTRAL MONTANA AND OVER THE FORECAST AREA. ALSO AN UPPER LOW WAS PRESENT OVER NEW MEXICO. MOISTURE HAS BEEN STREAMING NORTHWARD TOWARDS THE FORECAST AREA...DUE TO A SOUTHWARD PULL AHEAD OF BOTH THE UPPER LOW AND THE STRONG SHORTWAVE OVER THE AREA. PRECIPITABLE WATER PER GOES ANALYSIS HAS CLIMBED TO 0.5 INCH OVER SOUTHERN WI...AND 1 INCH ALONG I-70 IN MO AND IL. THIS MOISTURE...COMBINED WITH ISENTROPIC LIFT AND DPVA FORCING AHEAD OF THE SHORTWAVE OVER THE FORECAST AREA...HAS RESULTED IN SNOW ACROSS THE SOUTHEAST HALF OR SO OF THE FORECAST AREA. THE SNOW HAS NOW PUSHED INTO MAINLY WI...WITH SUBSIDENCE AND DRYING WORKING IN FROM THE WEST BEHIND THE SHORTWAVE. MEANWHILE...FARTHER WEST...A SURFACE LOW HAS DEVELOPED NEAR BISMARCK ND DOWNSTREAM OF THE MONTANA SHORTWAVE. 925MB TEMPS AHEAD OF THE LOW ARE GENERALLY 0 TO -6C ACROSS MUCH OF THE DAKOTAS EASTWARD INTO WI. HOWEVER...-20C TO -30C READINGS WERE LURKING TO THE NORTH ACROSS MUCH OF SOUTHERN CANADA. NORTHERLY WINDS BEHIND THE LOW HAS BEGUN BRINGING THIS COLD AIR SOUTH WITH READINGS OVER NORTHERN NORTH DAKOTA NOW IN THE SINGLE DIGITS BELOW ZERO. TODAY CONTINUES TO LOOK MUCH QUIETER ON THE PRECIPITATION SIDE OF THINGS...RESULTING MOSTLY FROM DECENT SUBSIDENCE AND DRYING OCCURRING IN THE WAKE OF THE SHORTWAVE CURRENTLY CROSSING THE FORECAST AREA. ANY LINGERING SNOW OVER WI SHOULD PUSH OFF TO THE EAST OF THE AREA BY 15Z. ALTHOUGH WE DO LOSE ICE IN THE CLOUDS WITH THE PASSAGE OF THE SHORTWAVE...WE ALSO LOSE THE LIFT...SO THE POTENTIAL FOR FREEZING DRIZZLE IS FURTHER REDUCED. MOST 03.00Z GUIDANCE IS NOW MOSTLY DRY FOR THE FORECAST AREA TODAY AND HAVE FOLLOWED SUIT. 925MB TEMPS STAY RELATIVELY MILD TODAY...-2 TO -4C. IF WE WERE SUNNY TODAY...HIGHS COULD POP INTO THE 40S OVER SNOW FREE AREAS. HOWEVER...A SOUTHERLY FLOW LOOKS TO ADVECT IN LOW CLOUDS FROM MO AND IL THROUGH THE FORECAST AREA...WHICH GET TRAPPED UNDER THE SUBSIDENCE INVERSION. IN FACT...CANNOT RULE OUT SOME FOG THIS MORNING OVER THE HIGHER TERRAIN. THESE CLOUDS SHOULD KEEP HIGHS IN THE UPPER 20S TO MID 30S...COLDEST OVER SNOW PACK LOCATIONS. NOW FOR TONIGHT...A LOT MORE IS GOING ON. 1. SNOW LOOKS LIKELY. WE SHOULD BEGIN TO SEE A SNOW BAND SET UP THIS AFTERNOON FROM CENTRAL NEBRASKA INTO NORTHEAST MN. THIS BAND... ASSOCIATED WITH MID LEVEL FRONTOGENESIS AND DPVA DOWNSTREAM OF THE CURRENT MONTANA SHORTWAVE TRACKING EAST...LOOKS TO MOVE INTO THE NORTHWEST HALF OF THE FORECAST AREA DURING THE EVENING...THEN MARCH EAST THROUGH THE REST OF THE FORECAST AREA OVERNIGHT. MODELS ARE IN PRETTY GOOD AGREEMENT IN PRODUCING A TOTAL OF 0.10-0.15 INCHES OF QPF WITH THE BAND...WHICH SEEMS REASONABLE WHEN LOOKING AT THE FORCING AND 0.3-0.4 INCHES OF PRECIPITABLE WATER. WITH SNOW RATIOS OF 15-18 TO 1 RANGE IN THE BAND...DUE TO COLDER AIR FLOWING IN ALLOWING FOR UPWARDS OF 100MB OF EFFECTIVE DENDRITIC GROWTH...A SOLID 1 TO 2 INCHES SEEMS REASONABLE WITH A 3 INCH AMOUNT POSSIBLE. 2. NORTHWEST WINDS ARE GOING TO INCREASE THROUGH THE NIGHT. THIS IN RESPONSE TO THE UPPER LOW EJECTING OUT OF NEW MEXICO AND PHASING WITH THE SHORTWAVE COMING THROUGH THE FORECAST AREA TONIGHT... RESULTING IN A DEEPENING SURFACE LOW LIFTING INTO THE EASTERN GREAT LAKES. 925MB WINDS INCREASE TO 35-40 KT BY 12Z SUNDAY...WHICH WITH PRESSURES RISING RAPIDLY AS THOSE WINDS DRIVE IN COLDER AIR...A GOOD AMOUNT OF THIS WIND SHOULD MIX DOWN. 20-25 KT WINDS FROM MAV GUIDANCE OVER THE HIGHER TERRAIN OF SOUTHEAST MN/NORTHEAST IA SEEMS REASONABLE...WITH GUSTS OF 30-35 KT. GIVEN THE FLUFFIER SNOW TONIGHT...SOME BLOWING AND DRIFTING IS LIKELY WITH THESE WINDS COMING THROUGH. 3. TEMPERATURES AND WIND CHILLS PLUMMETING OVERNIGHT. 925MB TEMPS TANK FROM THE -2 TO -4C AT 00Z TO -10 TO -20C BY 12Z...COLDEST NORTHWEST. THIS SHOULD DROP TEMPERATURES INTO THE SINGLE DIGITS AND TEENS...AND EVEN BELOW ZERO IN SOME OF SOUTHEAST MN BY SUNRISE. WIND CHILLS COULD BE APPROACHING ADVISORY CRITERIA BY 12Z SUNDAY IN PORTIONS OF SOUTHEAST MN. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE WESTERN PORTIONS OF SOUTHEAST MN AND NORTHEAST IA...FROM 06-12Z SUNDAY...TO HANDLE THE NEAR ADVISORY WINDS...FALLING SNOW...WIND CHILLS APPROACHING ADVISORY CRITERIA AND BLOWING/DRIFTING SNOW. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 311 AM CST SAT JAN 3 2015 MAIN LONG TERM FOCUSES ARE ON ARCTIC AIR AND A POSSIBLE ACCUMULATING FLUFFY SNOW EVENT FOR MONDAY NIGHT. THE POOL OF ARCTIC AIR SITUATED CURRENTLY ACROSS MUCH OF SOUTHERN CANADA LOOKS TO INVADE THE REGION SUNDAY AND SUNDAY NIGHT...THANKS TO THE SHORTWAVE OVER WEST CENTRAL ALBERTA DIGGING INTO THE REGION. 925MB TEMPS PLUMMET TO -20 TO -25C BY 00Z MONDAY ON A BRISK NORTHWEST WIND...AND FURTHER LOWERING TO -24 TO -28C BY 12Z MONDAY. TEMPERATURES THAT BEGAN FALLING TONIGHT WILL CONTINUE TO DO SO THROUGH THE DAY SUNDAY AND INTO SUNDAY NIGHT. COMBINED WITH THE BRISK NORTHWEST WIND...WIND CHILL ADVISORIES AND POSSIBLY A FEW WARNINGS ARE GOING TO BE NECESSARY. THE ARCTIC AIR MODIFIES SOMEWHAT ON MONDAY WITH 925MB TEMPS CLIMBING TO -18 TO -22C BY 00Z...ENOUGH THAT WIND CHILL HAZARDS SHOULD BE ALLOWED TO END BY 20Z. ON MONDAY NIGHT...A FAST MOVING BUT POTENT SHORTWAVE IS PROGGED TO AFFECT THE REGION. GOOD MODEL CONSENSUS EXISTS FOR STRONG MID LEVEL FRONTOGENESIS WITH DPVA ENHANCEMENT AND UPPER LEVEL DIVERGENCE TO ACCOMPANY THE SHORTWAVE. QPF FORECASTS ARE IN THE 0.25-0.4 INCH RANGE...WITH UPWARDS OF 200 MB OF EFFECTIVE DENDRITIC SNOW GROWTH. THIS WOULD MEAN EASILY 20 TO 1 RATIOS...QUITE FLUFFY SNOW...AND ACCUMULATIONS IN THE 4 TO 8 INCH RANGE. HOWEVER...PLACEMENT OF THE BAND IS BECOMING A SERIOUS ISSUE AS THERE HAS BEEN A TREND FOR THE SHORTWAVE TO TRACK FARTHER SOUTHWEST THROUGH IOWA IN THE 03.00Z GFS/CANADIAN/ECMWF. THIS TAKES THE HEAVIER SNOW FARTHER SOUTH. SO ITS HARD TO SAY RIGHT NOW EXACTLY HOW MUCH SNOW WE WILL SEE. AT THE MOMENT HAVE 2 TO 5 INCHES...HIGHEST SOUTH OF I-90. EXPECT THESE AMOUNTS TO CHANGE DUE TO BAND PLACEMENT AND INTENSITY. THE FARTHER SOUTHWEST TREND HAS RESULTED IN LOWERED PRECIPITATION CHANCES NORTH OF I-94. PRECIPITATION SHOULD BE OUT OF THE AREA FOR TUESDAY...WITH MORE ARCTIC AIR BEGINNING TO PLUNGE INTO THE REGION IN THE WAKE OF THE SYSTEM...ESPECIALLY TUESDAY NIGHT. 925MB TEMPS TANK FROM -10 TO -16C AT 12Z TO -16 TO -20C BY 00Z WEDNESDAY AND TO -25 TO -30C BY 12Z WEDNESDAY. 925MB WINDS ALSO PROGGED IN THE 35-45 KT RANGE. LUCKILY THE SOUNDING PROFILE MAY END UP BEING ISOTHERMAL TO HELP LIMIT MIXING OF THESE STRONGER WINDS...BUT ITS GOING TO BE BRISK NONETHELESS. MORE WIND CHILL ADVISORIES AND WARNINGS ARE LIKELY FOR TUESDAY NIGHT INTO WEDNESDAY. ADDITIONALLY...THE WIND WILL HELP BLOW THE RECENT FLUFFY SNOW AROUND SO ADDED SOME BLOWING SNOW. BRIEF UPPER RIDGING DROPS DOWN OVER THE FORECAST AREA WEDNESDAY NIGHT INTO THURSDAY...BRINGING SOMEWHAT WARMER AIR INTO THE FORECAST AREA. HOWEVER...COMBINATION OF THE WINDS AND LINGERING ARCTIC AIR LIKELY MEAN A CONTINUATION OF WIND CHILL HAZARDS INTO THURSDAY MORNING. RIGHT NOW HAVE THURSDAY DRY...BUT THE WARM ADVECTION MAY BE ENOUGH TO PRODUCE SOME LIGHT SNOW AND LATER FORECASTS COULD HAVE TO INTRODUCE PRECIPITATION CHANCES. ANOTHER ARCTIC SURGE LOOKS POISED TO FOLLOW FOR THURSDAY NIGHT THROUGH FRIDAY...NOT AS INTENSE AS EARLIER ONES THIS WEEK BUT STRONG ENOUGH TO POSSIBLY NEED A FEW MORE WIND CHILL ADVISORIES. FINALLY...LOOKING AHEAD...THERE IS SIGNAL SHOWING UP TO BREAK OUT OF THE ARCTIC REGIME FOR NEXT WEEKEND. IN FACT...THERE IS SIGNAL IN BOTH THE CFS AND ECMWF TO EVEN GO BACK ABOVE NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 529 AM CST SAT JAN 3 2015 MVFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH LATE THIS AFTERNOON THEN CONDITIONS WILL DETERIORATE TO LIFR IN SNOW AND BLOWING SNOW LATE THIS EVENING INTO THE OVERNIGHT HOURS. THE TAF SITES WILL BE IN BETWEEN STORM SYSTEMS DURING THE DAYTIME HOURS TODAY BUT THEN LOOK FOR SNOW TO OVERSPREAD THE REGION THIS EVENING INTO THE OVERNIGHT. ALSO...NORTHWEST WINDS WILL INCREASE TO 18 TO 22 KTS WITH GUSTS TO AROUND 32 KTS AT TIMES. SNOW ACCUMULATIONS OF 1 TO 2 INCHES ARE EXPECTED. THESE WINDS WILL CREATE BLOWING AND DRIFTING SNOW...ESPECIALLY AT KRST. LOOK FOR VISIBILITIES TO LOWER TO AROUND 1/2 MILE IN THE HEAVIER SNOW. ALSO...THE BLOWING SNOW WILL REDUCE THE VISIBILITY TO AROUND 1/2 MILE OR LESS THROUGH MUCH OF THE NIGHT INTO EARLY SUNDAY MORNING AT KRST. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY FOR MNZ086-087-094-095. IA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY FOR IAZ008>010-018-019-029. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
311 AM CST SAT JAN 3 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 311 AM CST SAT JAN 3 2015 CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED STRONG SHORTWAVES OVER WEST CENTRAL ALBERTA...EASTERN WASHINGTON STATE...NORTH CENTRAL MONTANA AND OVER THE FORECAST AREA. ALSO AN UPPER LOW WAS PRESENT OVER NEW MEXICO. MOISTURE HAS BEEN STREAMING NORTHWARD TOWARDS THE FORECAST AREA...DUE TO A SOUTHWARD PULL AHEAD OF BOTH THE UPPER LOW AND THE STRONG SHORTWAVE OVER THE AREA. PRECIPITABLE WATER PER GOES ANALYSIS HAS CLIMBED TO 0.5 INCH OVER SOUTHERN WI...AND 1 INCH ALONG I-70 IN MO AND IL. THIS MOISTURE...COMBINED WITH ISENTROPIC LIFT AND DPVA FORCING AHEAD OF THE SHORTWAVE OVER THE FORECAST AREA...HAS RESULTED IN SNOW ACROSS THE SOUTHEAST HALF OR SO OF THE FORECAST AREA. THE SNOW HAS NOW PUSHED INTO MAINLY WI...WITH SUBSIDENCE AND DRYING WORKING IN FROM THE WEST BEHIND THE SHORTWAVE. MEANWHILE...FARTHER WEST...A SURFACE LOW HAS DEVELOPED NEAR BISMARCK ND DOWNSTREAM OF THE MONTANA SHORTWAVE. 925MB TEMPS AHEAD OF THE LOW ARE GENERALLY 0 TO -6C ACROSS MUCH OF THE DAKOTAS EASTWARD INTO WI. HOWEVER...-20C TO -30C READINGS WERE LURKING TO THE NORTH ACROSS MUCH OF SOUTHERN CANADA. NORTHERLY WINDS BEHIND THE LOW HAS BEGUN BRINGING THIS COLD AIR SOUTH WITH READINGS OVER NORTHERN NORTH DAKOTA NOW IN THE SINGLE DIGITS BELOW ZERO. TODAY CONTINUES TO LOOK MUCH QUIETER ON THE PRECIPITATION SIDE OF THINGS...RESULTING MOSTLY FROM DECENT SUBSIDENCE AND DRYING OCCURRING IN THE WAKE OF THE SHORTWAVE CURRENTLY CROSSING THE FORECAST AREA. ANY LINGERING SNOW OVER WI SHOULD PUSH OFF TO THE EAST OF THE AREA BY 15Z. ALTHOUGH WE DO LOSE ICE IN THE CLOUDS WITH THE PASSAGE OF THE SHORTWAVE...WE ALSO LOSE THE LIFT...SO THE POTENTIAL FOR FREEZING DRIZZLE IS FURTHER REDUCED. MOST 03.00Z GUIDANCE IS NOW MOSTLY DRY FOR THE FORECAST AREA TODAY AND HAVE FOLLOWED SUIT. 925MB TEMPS STAY RELATIVELY MILD TODAY...-2 TO -4C. IF WE WERE SUNNY TODAY...HIGHS COULD POP INTO THE 40S OVER SNOW FREE AREAS. HOWEVER...A SOUTHERLY FLOW LOOKS TO ADVECT IN LOW CLOUDS FROM MO AND IL THROUGH THE FORECAST AREA...WHICH GET TRAPPED UNDER THE SUBSIDENCE INVERSION. IN FACT...CANNOT RULE OUT SOME FOG THIS MORNING OVER THE HIGHER TERRAIN. THESE CLOUDS SHOULD KEEP HIGHS IN THE UPPER 20S TO MID 30S...COLDEST OVER SNOW PACK LOCATIONS. NOW FOR TONIGHT...A LOT MORE IS GOING ON. 1. SNOW LOOKS LIKELY. WE SHOULD BEGIN TO SEE A SNOW BAND SET UP THIS AFTERNOON FROM CENTRAL NEBRASKA INTO NORTHEAST MN. THIS BAND... ASSOCIATED WITH MID LEVEL FRONTOGENESIS AND DPVA DOWNSTREAM OF THE CURRENT MONTANA SHORTWAVE TRACKING EAST...LOOKS TO MOVE INTO THE NORTHWEST HALF OF THE FORECAST AREA DURING THE EVENING...THEN MARCH EAST THROUGH THE REST OF THE FORECAST AREA OVERNIGHT. MODELS ARE IN PRETTY GOOD AGREEMENT IN PRODUCING A TOTAL OF 0.10-0.15 INCHES OF QPF WITH THE BAND...WHICH SEEMS REASONABLE WHEN LOOKING AT THE FORCING AND 0.3-0.4 INCHES OF PRECIPITABLE WATER. WITH SNOW RATIOS OF 15-18 TO 1 RANGE IN THE BAND...DUE TO COLDER AIR FLOWING IN ALLOWING FOR UPWARDS OF 100MB OF EFFECTIVE DENDRITIC GROWTH...A SOLID 1 TO 2 INCHES SEEMS REASONABLE WITH A 3 INCH AMOUNT POSSIBLE. 2. NORTHWEST WINDS ARE GOING TO INCREASE THROUGH THE NIGHT. THIS IN RESPONSE TO THE UPPER LOW EJECTING OUT OF NEW MEXICO AND PHASING WITH THE SHORTWAVE COMING THROUGH THE FORECAST AREA TONIGHT... RESULTING IN A DEEPENING SURFACE LOW LIFTING INTO THE EASTERN GREAT LAKES. 925MB WINDS INCREASE TO 35-40 KT BY 12Z SUNDAY...WHICH WITH PRESSURES RISING RAPIDLY AS THOSE WINDS DRIVE IN COLDER AIR...A GOOD AMOUNT OF THIS WIND SHOULD MIX DOWN. 20-25 KT WINDS FROM MAV GUIDANCE OVER THE HIGHER TERRAIN OF SOUTHEAST MN/NORTHEAST IA SEEMS REASONABLE...WITH GUSTS OF 30-35 KT. GIVEN THE FLUFFIER SNOW TONIGHT...SOME BLOWING AND DRIFTING IS LIKELY WITH THESE WINDS COMING THROUGH. 3. TEMPERATURES AND WIND CHILLS PLUMMETING OVERNIGHT. 925MB TEMPS TANK FROM THE -2 TO -4C AT 00Z TO -10 TO -20C BY 12Z...COLDEST NORTHWEST. THIS SHOULD DROP TEMPERATURES INTO THE SINGLE DIGITS AND TEENS...AND EVEN BELOW ZERO IN SOME OF SOUTHEAST MN BY SUNRISE. WIND CHILLS COULD BE APPROACHING ADVISORY CRITERIA BY 12Z SUNDAY IN PORTIONS OF SOUTHEAST MN. HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE WESTERN PORTIONS OF SOUTHEAST MN AND NORTHEAST IA...FROM 06-12Z SUNDAY...TO HANDLE THE NEAR ADVISORY WINDS...FALLING SNOW...WIND CHILLS APPROACHING ADVISORY CRITERIA AND BLOWING/DRIFTING SNOW. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 311 AM CST SAT JAN 3 2015 MAIN LONG TERM FOCUSES ARE ON ARCTIC AIR AND A POSSIBLE ACCUMULATING FLUFFY SNOW EVENT FOR MONDAY NIGHT. THE POOL OF ARCTIC AIR SITUATED CURRENTLY ACROSS MUCH OF SOUTHERN CANADA LOOKS TO INVADE THE REGION SUNDAY AND SUNDAY NIGHT...THANKS TO THE SHORTWAVE OVER WEST CENTRAL ALBERTA DIGGING INTO THE REGION. 925MB TEMPS PLUMMET TO -20 TO -25C BY 00Z MONDAY ON A BRISK NORTHWEST WIND...AND FURTHER LOWERING TO -24 TO -28C BY 12Z MONDAY. TEMPERATURES THAT BEGAN FALLING TONIGHT WILL CONTINUE TO DO SO THROUGH THE DAY SUNDAY AND INTO SUNDAY NIGHT. COMBINED WITH THE BRISK NORTHWEST WIND...WIND CHILL ADVISORIES AND POSSIBLY A FEW WARNINGS ARE GOING TO BE NECESSARY. THE ARCTIC AIR MODIFIES SOMEWHAT ON MONDAY WITH 925MB TEMPS CLIMBING TO -18 TO -22C BY 00Z...ENOUGH THAT WIND CHILL HAZARDS SHOULD BE ALLOWED TO END BY 20Z. ON MONDAY NIGHT...A FAST MOVING BUT POTENT SHORTWAVE IS PROGGED TO AFFECT THE REGION. GOOD MODEL CONSENSUS EXISTS FOR STRONG MID LEVEL FRONTOGENESIS WITH DPVA ENHANCEMENT AND UPPER LEVEL DIVERGENCE TO ACCOMPANY THE SHORTWAVE. QPF FORECASTS ARE IN THE 0.25-0.4 INCH RANGE...WITH UPWARDS OF 200 MB OF EFFECTIVE DENDRITIC SNOW GROWTH. THIS WOULD MEAN EASILY 20 TO 1 RATIOS...QUITE FLUFFY SNOW...AND ACCUMULATIONS IN THE 4 TO 8 INCH RANGE. HOWEVER...PLACEMENT OF THE BAND IS BECOMING A SERIOUS ISSUE AS THERE HAS BEEN A TREND FOR THE SHORTWAVE TO TRACK FARTHER SOUTHWEST THROUGH IOWA IN THE 03.00Z GFS/CANADIAN/ECMWF. THIS TAKES THE HEAVIER SNOW FARTHER SOUTH. SO ITS HARD TO SAY RIGHT NOW EXACTLY HOW MUCH SNOW WE WILL SEE. AT THE MOMENT HAVE 2 TO 5 INCHES...HIGHEST SOUTH OF I-90. EXPECT THESE AMOUNTS TO CHANGE DUE TO BAND PLACEMENT AND INTENSITY. THE FARTHER SOUTHWEST TREND HAS RESULTED IN LOWERED PRECIPITATION CHANCES NORTH OF I-94. PRECIPITATION SHOULD BE OUT OF THE AREA FOR TUESDAY...WITH MORE ARCTIC AIR BEGINNING TO PLUNGE INTO THE REGION IN THE WAKE OF THE SYSTEM...ESPECIALLY TUESDAY NIGHT. 925MB TEMPS TANK FROM -10 TO -16C AT 12Z TO -16 TO -20C BY 00Z WEDNESDAY AND TO -25 TO -30C BY 12Z WEDNESDAY. 925MB WINDS ALSO PROGGED IN THE 35-45 KT RANGE. LUCKILY THE SOUNDING PROFILE MAY END UP BEING ISOTHERMAL TO HELP LIMIT MIXING OF THESE STRONGER WINDS...BUT ITS GOING TO BE BRISK NONETHELESS. MORE WIND CHILL ADVISORIES AND WARNINGS ARE LIKELY FOR TUESDAY NIGHT INTO WEDNESDAY. ADDITIONALLY...THE WIND WILL HELP BLOW THE RECENT FLUFFY SNOW AROUND SO ADDED SOME BLOWING SNOW. BRIEF UPPER RIDGING DROPS DOWN OVER THE FORECAST AREA WEDNESDAY NIGHT INTO THURSDAY...BRINGING SOMEWHAT WARMER AIR INTO THE FORECAST AREA. HOWEVER...COMBINATION OF THE WINDS AND LINGERING ARCTIC AIR LIKELY MEAN A CONTINUATION OF WIND CHILL HAZARDS INTO THURSDAY MORNING. RIGHT NOW HAVE THURSDAY DRY...BUT THE WARM ADVECTION MAY BE ENOUGH TO PRODUCE SOME LIGHT SNOW AND LATER FORECASTS COULD HAVE TO INTRODUCE PRECIPITATION CHANCES. ANOTHER ARCTIC SURGE LOOKS POISED TO FOLLOW FOR THURSDAY NIGHT THROUGH FRIDAY...NOT AS INTENSE AS EARLIER ONES THIS WEEK BUT STRONG ENOUGH TO POSSIBLY NEED A FEW MORE WIND CHILL ADVISORIES. FINALLY...LOOKING AHEAD...THERE IS SIGNAL SHOWING UP TO BREAK OUT OF THE ARCTIC REGIME FOR NEXT WEEKEND. IN FACT...THERE IS SIGNAL IN BOTH THE CFS AND ECMWF TO EVEN GO BACK ABOVE NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1140 PM CST FRI JAN 2 2015 A BAND OF SNOW HAS DEVELOPED ACROSS PARTS OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN LATE THIS EVENING. THE SNOW REDUCED THE VISIBILITY AT KOLZ TO 2 MILES BRIEFLY. THE NAM AND RAP SHOW THAT THE 850 TO 500 MB FRONTOGENESIS ASSOCIATED WITH THIS BAND WILL MOVE NORTHEAST INTO KLSE AROUND 03.07Z...SO LOWERED THE CEILINGS TO MVFR AND VISIBILITIES TO 2 MILES. THIS FRONTOGENESIS THEN EXITS THE AREA AROUND 03.11Z. SNOW ACCUMULATIONS OF A ROUND A HALF INCH ARE EXPECTED. MEANWHILE KRST WILL MISS THE PRECIPITATION FROM THIS BAND...BUT WILL SEE CEILINGS BECOME MVFR. ON SATURDAY EVENING...THE LONG WAVE TROUGH WILL MOVE INTO SOUTHEAST MINNESOTA. AS THIS OCCURS...EXPECT VISIBILITIES AT KRST TO DROP TO 1 MILE AND CEILINGS TO BECOME IFR AROUND 04.04Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY FOR MNZ086-087-094-095. IA...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY FOR IAZ008>010-018-019-029. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CST FRI JAN 2 2015 .UPDATE... ISSUED AT 906 PM CST FRI JAN 2 2015 STARTING TO GET REPORTS OF FLURRIES ACROSS PARTS OF IOWA. TALKED WITH THE DES MOINES OFFICE AND THEY SAID THAT THEY WERE GETTING FLURRIES AT BOTH THE OFFICE AND AIRPORT. THIS IS LINKED TO THE 800 TO 500 MB FRONTOGENESIS. BOTH THE LATEST RAP AND 03.00Z RAP SHOW THAT THIS FORCING WILL MOVE IN AND INCREASE IN INTENSITY BETWEEN BETWEEN 02.04Z AND 02.06Z ACROSS SOUTHWEST WISCONSIN AND NORTHERN IOWA. PLAN ON MOVING THE SNOW CHANCES INTO THE AREA EARLIER AREA. SOUNDINGS CONTINUE TO SUGGEST SNOW EARLY...AND THEN POSSIBLY TAPERING OFF TO FREEZING DRIZZLE AS IT ENDS. THINKING THAT WE HAVE TOO MUCH PRECIPITATION CHANCES FOR SATURDAY MORNING...SO MAY HAVE TO ADJUST THEM LOWER OR REMOVE THEM...BUT WILL WAIT A FEW MORE HOURS BEFORE DOING THAT. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 321 PM CST FRI JAN 2 2015 THE MAIN CONCERNS ARE WITH THE PRECIPITATION CHANCES THROUGH THE PERIOD. WATER VAPOR SATELLITE THIS AFTERNOON SHOWING AN UPPER LEVEL LOW OVER NEBRASKA. THE 02.12Z MODELS ALL IN GOOD AGREEMENT IN SHOWING THIS LOW BECOMING AN OPEN WAVE AND LIFTING ACROSS THE REGION LATE TONIGHT INTO SATURDAY MORNING. DESPITE THE FACT THAT THIS SYSTEM WILL BE WEAKENING SOME AS IT COMES ACROSS...IT IS STILL EXPECTED TO BE ABLE TO PRODUCE MODERATE TO STRONG PV ADVECTION IN THE 500-300 MB LAYER AS IT MOVES ACROSS. THE QG CONVERGENCE SHOULD BE WEAK IN THE 850-700 MB LAYER AND THEN BECOME MODERATE IN STRENGTH ABOVE THAT. WITH THE RAPID MOVEMENT OF THE WAVE...THE WARM AIR ADVECTION AHEAD OF IT DOES NOT HAVE MUCH TIME TO GET GOING...BUT STILL ENOUGH TO PRODUCE 1 TO 2 UBAR/S OF UP GLIDE ON THE 285K ISENTROPIC SURFACE. LOW LEVEL MOISTURE IS ALREADY STARTING TO RETURN NORTH AHEAD OF THIS SYSTEM WITH LOWER 30S DEW POINTS SPREADING INTO NORTHERN MISSOURI. THIS MOISTURE WILL CONTINUE TO SPREAD RAPIDLY NORTH AND SHOULD GET INTO THE EASTERN SECTIONS OF THE FORECAST AREA OVERNIGHT. WITH THIS MOISTURE RETURN AND THE FORCING FROM THE WAVE...EXPECT THAT THERE WILL BE LIGHT PRECIPITATION THAT DEVELOPS AFTER MIDNIGHT AND CONTINUES INTO EARLY SATURDAY MORNING. WITH THE INITIAL BURST OF FORCING...THE BUFKIT SOUNDINGS SUGGEST THIS WILL BE STRONG ENOUGH TO PRODUCE DEEP SATURATION TO ALLOW ICE TO BE IN THE CLOUDS AND FOR THE PRECIPITATION TO START OUT AS SNOW. HOWEVER...AS THE FORCING WEAKENS...THE SATURATION GETS SHALLOWER AND ICE IN THE CLOUDS IS LOST AND MOST LIKELY TAKING THE PRECIPITATION OVER TO LIGHT FREEZING DRIZZLE. THIS IS NOT EXPECTED TO LAST VERY LONG WITH JUST A COUPLE HUNDREDTHS OF ICING POSSIBLE AND WITH SNOW AMOUNTS LESS THAN AN INCH...NOT PLANNING TO ISSUE AN ADVISORY FOR THIS EVENT. ONCE THIS WAVE MOVES PAST THE AREA...IT LOOKS LIKE THERE WILL BE A PERIOD FROM SATURDAY AFTERNOON INTO THE EVENING WHERE THERE MAY NOT BE ANY PRECIPITATION OCCURRING OR IT WOULD BE VERY LIGHT AT BEST. IF THERE IS ANYTHING OCCURRING...IT COULD BE SOME LIGHT FREEZING DRIZZLE WITH A SHALLOW CLOUD DEPTH AND A LACK OF ICE IN THE CLOUDS. WILL AGAIN SHOW JUST A LITTLE BIT OF ICE ACCUMULATION IN THESE PERIODS AS CONFIDENCE THAT THERE WILL EVEN BE ANY PRECIPITATION OCCURRING IS PRETTY LOW. AFTER THAT...THE PRECIPITATION CHANCES PICK UP AGAIN FOR SATURDAY NIGHT. THE MAIN UPPER LEVEL LOW OVER THE DESERT SOUTHWEST WILL BE LIFTING NORTHEAST ACROSS THE CENTRAL MISSISSIPPI RIVER VALLEY TOWARD THE EASTERN GREAT LAKES. AT THE SAME TIME...A NORTHERN STREAM SHORT WAVE TROUGH WILL BE MOVING ALONG THE CANADIAN BORDER. THE SYSTEM COMING UP FROM THE SOUTHWEST SHOULD PRODUCE STRONG PV ADVECTION ACROSS THE SOUTHERN PART OF THE AREA SATURDAY EVENING WITH MODERATE PV ADVECTION ACROSS MOST OF THE AREA OVERNIGHT SATURDAY INTO EARLY SUNDAY MORNING FROM THE NORTHERN STREAM WAVE. THE BEST PERIOD OF QG CONVERGENCE WILL COME FROM THE SOUTHWEST SYSTEM AND THIS IS EXPECTED TO BE WEAK TO MODERATE IN STRENGTH. THE FRONTOGENESIS DOES NOT LOOK TO BE VERY STRONG WITH EITHER OF THESE WAVES AND SHOULD BE CONFINED TO THE 1000-700 MB LAYER. THE ISENTROPIC UP GLIDE AGAIN LOOKS TO BE BETWEEN 1 AND 2 UBAR/S ON THE 285K SURFACE. THE FORCING FROM THESE TWO WAVES SHOULD ALLOW A BAND OF DEFORMATION PRECIPITATION TO DEVELOP ON THE NORTHWEST SIDE OF THE SURFACE LOW AS IT PASSES BY TO THE SOUTHEAST. AS THE FORCING INCREASES AND COLDER AIR MOVES IN...THE PRECIPITATION WILL EVENTUALLY BECOME ALL SNOW...BUT STILL SOME CONCERNS ABOUT ICE IN THE CLOUDS FOR SATURDAY EVENING AND WILL SHOW EITHER FREEZING DRIZZLE OR A MIX OF FREEZING AND DRIZZLE AND SNOW GOING OVER TO ALL SNOW. THE HEAVIER PRECIPITATION AMOUNT FROM THIS SYSTEM WILL REMAIN SOUTHEAST OF THE AREA SO GENERALLY CAN EXPECT 1 TO 2 INCHES OF SNOW FOR MUCH OF THE AREA SATURDAY NIGHT INTO SUNDAY MORNING. THE WINDS ON THE BACK SIDE OF THE LOW WILL INCREASE SATURDAY NIGHT INTO SUNDAY MORNING ENOUGH TO DEFINITELY PRODUCE SOME DRIFTING SNOW AND DEPENDING ON HOW MUCH FRESH SNOW THERE IS...SOME BLOWING SNOW. BLOWING SNOW WAS ALREADY IN THE WESTERN SECTIONS OF THE AREA AND INCREASED THE PROBABILITIES OF THIS AND ALSO EXPANDED THE AREAL COVERAGE TO THE REMAINDER OF THE AREA. THESE WINDS WILL START TO DIMINISH SOME DURING THE AFTERNOON BUT WITH THE PLUMMETING AIR TEMPERATURES...WIND CHILL VALUES ACROSS THE WESTERN AND NORTHERN SECTIONS WILL LIKELY BE IN THE ADVISORY RANGE FOR MUCH OF THE DAY. BY EVENING...ADVISORY WIND CHILLS SHOULD BE OVER THE ENTIRE AREA WITH THE POSSIBILITY OF WARNING CRITERIA BEING REACHED IN THE NORTHERN SECTIONS FOR THE OVERNIGHT AREAS. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 321 PM CST FRI JAN 2 2015 THE BITTERLY COLD WIND CHILLS WILL CONTINUE INTO MONDAY MORNING BEFORE BRIEFLY IMPROVING FOR THE AFTERNOON. ADVISORY CRITERIA FOR THE WIND CHILLS LOOK TO BE POSSIBLE AGAIN MONDAY NIGHT ACROSS THE NORTHERN AND WESTERN SECTIONS OF THE AREA. THE MODELS HAVE BEEN SHOWING FOR A WHILE NOW THAT A FAST MOVING NORTHERN STREAM SYSTEM SHOULD ZIP ACROSS THE REGION EARLY NEXT WEEK. THERE HAS BEEN SOME TIMING DIFFERENCES BETWEEN...BUT THE 02.12Z GFS AND ECMWF LOOK TO BE CLOSER ON THIS. CURRENT INDICATIONS ARE THAT THIS WILL BE ABLE TO PRODUCE MODERATE TO STRONG PV ADVECTION IN THE 500-300 MB LAYER WITH STRONG AND DEEP QG CONVERGENCE. STRONG WARM AIR ADVECTION IS INDICATED AHEAD OF THE SURFACE LOW RESULTING IN UP TO 8 UBAR/S OF UP GLIDE ON THE 275K SURFACE. IF THESE FORCING SIGNALS REMAIN CONSISTENT...THIS SYSTEM COULD HAVE THE POTENTIAL TO PRODUCE MORE SNOW THAN WHAT OCCURS OVER THE WEEKEND. WITH THE COLD AIR ALREADY IN PLACE...SNOW RATIOS SHOULD BE RATHER HIGH MAKING FOR LIGHT AND FLUFFY SNOW THAT WOULD THEN EASILY BE MOVED AROUND BY THE STRONG WINDS THAT SHOULD DEVELOP ON THE BACK SIDE OF THE SURFACE LOW. THE IMPACT FROM THIS SYSTEM COULD BE GREATER THAN THE WEEKEND AND THERE IS THE POTENTIAL FOR WINTER HEADLINES AS IT COMES THROUGH. WIND CHILLS WILL AGAIN BECOME A CONCERN BEHIND THIS SYSTEM AND WIND CHILL ADVISORIES WILL LIKELY BE NEEDED TUESDAY NIGHT INTO WEDNESDAY MORNING AND AGAIN WEDNESDAY NIGHT INTO THURSDAY MORNING. WARNINGS MAY BE NEEDED AS WELL FOR PARTS OF THE AREA TUESDAY NIGHT/WEDNESDAY MORNING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1140 PM CST FRI JAN 2 2015 A BAND OF SNOW HAS DEVELOPED ACROSS PARTS OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN LATE THIS EVENING. THE SNOW REDUCED THE VISIBILITY AT KOLZ TO 2 MILES BRIEFLY. THE NAM AND RAP SHOW THAT THE 850 TO 500 MB FRONTOGENESIS ASSOCIATED WITH THIS BAND WILL MOVE NORTHEAST INTO KLSE AROUND 03.07Z...SO LOWERED THE CEILINGS TO MVFR AND VISIBILITIES TO 2 MILES. THIS FRONTOGENESIS THEN EXITS THE AREA AROUND 03.11Z. SNOW ACCUMULATIONS OF A ROUND A HALF INCH ARE EXPECTED. MEANWHILE KRST WILL MISS THE PRECIPITATION FROM THIS BAND...BUT WILL SEE CEILINGS BECOME MVFR. ON SATURDAY EVENING...THE LONG WAVE TROUGH WILL MOVE INTO SOUTHEAST MINNESOTA. AS THIS OCCURS...EXPECT VISIBILITIES AT KRST TO DROP TO 1 MILE AND CEILINGS TO BECOME IFR AROUND 04.04Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BOYNE SHORT TERM...04 LONG TERM...04 AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS ALBANY NY
1110 PM EST SUN JAN 4 2015 .SYNOPSIS... ONE COLD FRONT HAS ALREADY CROSSED OUR REGION. ANOTHER COLD FRONT WILL CROSS THE REGION TOWARD DAYBREAK. THIS WILL BE THE ONE THAT REALLY BRINGS THE COLD AIR ALONG WITH MORE GUSTY WINDS AND ADDITIONAL SHOWERS OF MOSTLY SNOW...MAINLY NORTHWEST OF ALBANY.IT WILL BE BLUSTERY AND COLD MONDAY. A CLIPPER LOOKS TO BRING A LITTLE SNOW ON TUESDAY FOLLOWED BY EVEN COLDER WEATHER WEDNESDAY AND THURSDAY. && .NEAR TERM /THROUGH MONDAY/... AS OF 945 PM EST...A COLD FRONT HAS SLIPPED THROUGH MOST OF OUR REGION. HOWEVER...AS THE RIGHT REAR REGION OF A 150KT JET HAS WORKED INTO OUR REGION...IT HAS ALLOWED ANOTHER AREA OF SHOWERS TO EXPAND IN OUR SOUTHEAST ZONES. HAD TO INCREASE POPS IN THAT THAT AREA FOR AWHILE THIS EVENING. THIS RR REGION WILL SHIFT TO OUR SOUTH AFTER MIDNIGHT TAKING THOSE SHOWERS WITH IT. MEANWHILE...A SECONDARY COLD FRONT...THE ONE WITH ARCTIC AIR...WAS WORKING INTO WESTERN NEW YORK. THIS FRONT WILL CROSS OUR REGION TOWARD DAYBREAK BRINGING PERHAPS A STRAY SHOWER ON ITS OWN...ALONG WITH MORE GUSTY WINDS AND THE REAL TEMPERATURE CHANGE. FOR THIS UPDATE...TRENDED HOURLY TEMPERATURES UPWARD A BIT AS THEY WILL ONLY SLOWLY FALL THROUGH THE EARLY OVERNIGHT...NOT FALLING TO BELOW FREEZING UNTIL DAYBREAK...FROM THE HUDSON VALLEY EASTWARD. TEMPERATURES WERE CLOSE TO FREEZING ACROSS THE ADIRONDACKS...AND WILL DROP BELOW FREEZING ACROSS THE REMAINDER OF THE HIGHER TERRAIN SHORTLY AFTER MIDNIGHT. LAKE EFFECT SHOWERS WERE BEGINNING TO WORK INTO THE ADIRONDACKS...PROBABLY A SNOW RAIN MIX IN THE VALLEYS...ALL SNOW HIGHER TERRAIN...BUT WILL SWITCH TO ALL SNOW BY MIDNIGHT. WE WILL KEEP ALL ADVISORIES UP THE WAY THEY WERE HANDED TO US. BY DAYBREAK...LOWS WILL BE DOWN NEAR 20 ACROSS THE DACKS AND MUCH OF THE REMAINDER OF THE ELEVATED TERRAIN. VALLEY AREAS WILL BE CLOSER TO 30. && .SHORT TERM /MONDAY NIGHT/... LAKE EFFECT SNOW ADVISORY ISSUED FROM 7 PM SUNDAY TO 7 AM MONDAY FOR NORTHERN HERKIMER AND HAMILTON COUNTIES... ...LAKE EFFECT SNOW ADVISORY ISSUED FROM 4 AM MONDAY TO 7 PM MONDAY FOR SOUTHERN HERKIMER...FULTON AND MONTGOMERY COUNTIES. THE ADVISORIES ARE FOR SNOW AND BLOWING SNOW WITH GUSTY WINDS OF 35 TO 45 MPH. OUR CONFIDENCE WAS NOT GREAT ENOUGH TO ISSUE A WIND ADVISORY FOR PARTS OF THE REGION SUNDAY NIGHT...THOUGH A 3RD PERIOD ADVISORY MAY BE NEEDED FOR MONDAY...AS BETTER MOMENTUM TRANSFER IS EXPECTED...BUT FOR NOW WIDESPREAD 46-57 MPH WIND GUSTS ARE NOT ANTICIPATED FOR SUNDAY NIGHT INTO MONDAY. THIS WILL CONTINUE TO BE MONITORED. TONIGHT...COLD FRONT MOVES ACROSS THE REGION WITH STRONG LOW LEVEL COLD ADVECTION EXPECTED. WESTERLY UPSLOPE SNOW SHOWERS WILL INITIALLY IMPACT THE WRN DACKS AND SRN GREENS MTNS WITH MORE SCT RAIN AND SNOW SHOWER ACTIVITY AWAY FROM THESE AREAS. THE LATEST HIRES WRF AND 3-KM HRRR INDICATE A TRANSITION FROM THE WESTERLY UPSLOPE SNOW SHOWERS OVER THE WRN DACKS TO AN ORGANIZED SINGLE BAND. BUFKIT PROFILES JUST DOWNSTREAM OF LAKE ONTARIO INDICATED MODERATE INSTABILITY WITH AN INVERSION HEIGHT CLOSE TO 10 KFT. HOWEVER...THE BAND IS EXPECTED TO FORM AND QUICKLY TRANSITION S/SE WITH THE STRONG VEERING WIND PROFILE IN THE BOUNDARY LAYER. THE LOW LEVEL FLOW STARTS AT 260-270 DEGS AND THEN SHIFTS TO A 280 TO 290 DEG LOW-LEVEL TRAJECTORY. A QUICK BLAST OF HVY SNOW SHOWERS IS ANTICIPATED FOR THE WRN DACKS WITH 3 TO 6 INCHES OF SNOW WITH PERHAPS SOME 4 TO 8 INCH AMOUNTS JUST SOUTH OF OLD FORGE AND INLET. THE TRANSITORY BAND MOVES INTO SRN HERKIMER COUNTY...AND THE W-CNTRL MOHAWK VALLEY BTWN 4-7 AM. THE NAM AND HIRES WRF SHOW A MULTI-LAKE CONNECTION WITH MDT INSTABILITY CLASS AT KUCA BUFKIT PROFILE. THIS AREA MAY NEED AN UPGRADE LATER...BUT WE PUT THE ENTIRE W-CNTRL MOHAWK VALLEY CORRIDOR WAS ALSO PLACED IN A LAKE EFFECT SNOW ADVISORY FOR SNOW AND BLOWING SNOW. ADVISORY WIND LEVEL GUSTS WILL BE CLOSE WITH 35 TO 45 MPH GUSTS FORECASTED. LOWS WILL BE MUCH COLDER IN THE TEENS TO M20S WITH SOME SINGLE DIGITS OVER THE ADIRONDACK PARK...AND U20S OVER THE MID HUDSON VALLEY. MONDAY...THE BETTER PRESSURE RISES PASS NORTH OF ST LAWRENCE RIVER VALLEY AND NRN NY BTWN 12Z-18Z MON 8-10 HPA/6 HRS. THE ISALLOBARIC COUPLET IS IMPRESSIVE AS THE CYCLONE DEEPENS AND INTENSIFIES TO ABOUT 980 HPA OVER THE GULF OF ST LAWRENCE BY 12Z/MON. SOME SUSTAINED WESTERLY WINDS OF 15 TO 25 MPH WITH GUSTS 35 TO 45 MPH ARE EXPECTED. THE 10-M WINDS ON THE GFSMOS PRODUCT FOR KALB ARE IMPRESSIVE IN THE 18-24 KT SUSTAINED RANGE. THE BUFKIT MOMENTUM TRANSFER PROFILES SHOW 40 KTS WILL NEED TO MIXED FROM 2.5 KFT AGL FOR WIND ADVISORY CRITERIA TO BE MET. ANY WIND FLAGS WILL BE MONITORED BY LATER SHIFTS. IT DOES LOOK PLAUSIBLE THAT SOME LAKE EFFECT SHOWERS MAY SNEAK DOWN THE MOHAWK RIVER VALLEY INTO THE CAPITAL REGION AND NRN TACONICS. HIGH CHC AND LIKELY POPS WERE USED LATE MONDAY MORNING INTO THE PM FOR A COATING TO PERHAPS A HALF AN INCH OF SNOW. SOME OF THE UPSLOPE AREAS OF THE SRN GREENS IN THE SRN VT...TACONICS...AND NRN BERKS COULD GET AN INCH OR TWO OR SNOW. THE ADVISORY AREA HIGHLIGHTED WILL LIKELY RECEIVE 3 TO 6 INCHES WITH SOME ISOLATED 4 TO 8 INCH AMOUNTS. THE INVERSION HEIGHTS DO LOWER IN THE AFTERNOON...AND THE SHEAR INCREASES SO THE DOWNSTREAM TRAJECTORY WILL DECREASE. MAX TEMPS MAY BE IN THE MORNING...AND TEMPS MAY CONTINUE TO FALL SLOWLY IN THE AFTERNOON IN THE POTENT COLD ADVECTION REGIME...AS H850 TEMPS CRASH INTO THE -17C TO -22C RANGE ACROSS THE FCST AREA. DAYTIME HIGHS WILL BE IN THE M20S TO L30S FROM THE TRI CITIES SOUTH AND EAST...AND TEENS TO L20S NORTH AND WEST WITH SOME SINGLE NUMBERS OVER THE SRN DACKS. WIND CHILLS WILL RANGE FROM 10 BELOW TO 10 ABOVE ZERO. MONDAY NIGHT...LAKE EFFECT SNOW BAND LIFTS BACK NORTHWARD...AS THE FLOW BACKS WITH AN APPROACHING SHORT-WAVE/CLIPPER LOW FROM THE GREAT LAKES REGION AND MIDWEST. HIGH PRESSURE BRIEFLY BUILDS IN FROM QUEBEC WITH A VERY COLD NIGHT EXPECTED. THE WINDS SHOULD DIMINISH...AND FRIGID TEMPS ARE ANTICIPATED WITH LOWS BELOW ZERO OVER THE SRN DACKS...AND PARTS OF THE LAKE REGION REGION...AND ZERO TO 10 ABOVE IN MOST OTHER LOCATIONS WITH SOME LOWER TEENS IN THE CAPITAL DISTRICT AND MID HUDSON VALLEY. CLOUDS WILL INCREASE IN THE FRIGID AIR MASS WITH THE BETTER CHANCE FOR LIGHT SNOW AND SCT SNOW SHOWERS ON TUE. && .LONG TERM /TUESDAY THROUGH SUNDAY/... OVERALL TEMPERATURES WILL BE WELL BELOW NORMAL DURING THE EXTENDED PERIOD. PRECIPITATION GENERALLY BE BELOW NORMAL DESPITE DEALING WITH A LOT OF DISTURBANCES RIPPLING THROUGH THE POLAR JET. WEDNESDAY...WE WILL BE DEALING WITH FIRST SURGE OF ARCTIC AIR BEHIND THE CLIPPER SYSTEM. HOWEVER...A SECONDARY COLD FRONT LOOKS TO WORK THROUGH THE REGION DURING THE DAY...WITH MORE SCATTERED SNOW SHOWERS AND POSSIBLY MORE DISRUPTIVE SNOW SQUALLS. WE WILL HAVE TO MONITOR IF ANY OF THESE COME TO FRUITION AS THEY COULD CAUSE VERY BRIEF REDUCTIONS IN VISIBLITY AND QUICKLY TURN ROADS INTO ICE SKATING RINKS. IF THEY DO...WE WILL ISSUE SPECIAL WEATHER STATEMENTS AS NEEDED. EITHER WAY...THE COLDEST WEATHER OF THE WINTER WILL POUR IN BEHIND THE COLD...AS THE AIR...TAPPED STRAIGHT FROM NORTHERN CANADA...WILL DRIVE H850 TEMPERATURES TO BETWEEN -25C AND -30C OVER OUR REGION. BTW...THE LAST TIME H850 TEMPERATURES WERE MEASURED AT -30C AT ALBANY WAS JAN 16 2004. THEY COULD GET VERY CLOSE TO THESE VALUES ON THURSDAY MORNING! AFTERWARDS...THE ARCTIC AIR WILL MODERATE A BIT FRIDAY BEFORE ANOTHER CLIPPER AND PERHAPS A WEAK COASTAL STORM...BRING A REINFORCING SHOT OF LESS COLD FOR EARLY NEXT WEEK. A NORTHWESTERLY TO WESTERLY FLOW OF EXTREMELY COLD AIR WORKING OVER THE RELATIVELY WARM LAKE WATERS...WILL LIKELY TRIGGER BANDS OF LAKE EFFECT SNOW OFF ONTARIO...VACILLATING BETWEEN THE ADIRONDACKS...MOHAWK AND CATSKILLS...AND EVEN OCCASIONALLY DUCTING ENOUGH MOISTURE FOR UPSLOPE SNOW SHOWERS ACROSS THE SOUTHERN GREENS. THESE BANDS COULD BRING SEVERAL INCHES OF SNOWFALL IN SPOTS DOWNWIND OF ONTARIO AND PERHAPS THE SOUTHERN GREENS. MOST OF THE REMAINDER OF THE REGION WILL BE DRY WEDNESDAY NIGHT THROUGH FRIDAY WITH PARTIAL SUNSHINE...WITH PERHAPS A FEW FLURRIES. AGAIN...THE BIG NEWS WILL BE BRUTAL COLD...ESPECIALLY WEDNESDAY NIGHT INTO THURSDAY WHEN TEMPERATURES ARE FORECAST TO PLUMMET TO NEAR ZERO IN THE HUDSON VALLEY SOUTH OF ALBANY...ZERO TO 10 BELOW CAPITAL REGION AND SURROUNDING AREAS...AND AS LOW AS 20 BELOW ACROSS THE ADIRONDACKS. THIS ARE THE ACTUAL TEMPERATURES. WHEN ONE FACTORS IN A NORTHWEST WIND OF 10-15 MPH...WIND CHILL VALUES WILL BE DRIVEN TO DANGEROUSLY LOW LEVEL AS LOW AS -25 TO -40 DEGREES!!! WIND CHILL HEADLINES WILL LIKELY BE ISSUED WEDNESDAY INTO THURSDAY MORNING TO COVER THIS DANGEROUS COLD. HIGHS ON THURSDAY WILL STRUGGLE TO GET OUT OF THE SINGLE NUMBERS NORTH...AND ONLY REACH INTO THE TEENS FROM THE CAPITAL REGION SOUTHWARD. THE WIND WILL ABATE SO EVENTUALLY BY THURSDAY AFTERNOON...WIND CHILLS WILL NOT BE AS HARSH. WARM AIR ADVECTION ON THE BACK SIDE OF HIGH PRESSURE WILL BRING CLOUDS AND PERHAPS SOME SNOW SHOWERS THURSDAY NIGHT INTO FRIDAY. TEMPERATURES WILL NOT DROP MUCH THURSDAY NIGHT AND THEN RISE BACK INTO THE TEENS NORTH AND 20S SOUTH ON FRIDAY. WEAK HIGH PRESSURE SHOULD REBUILD BACK IN ON SATURDAY WITH TEMPERATURES SIMILAR TO FRIDAY AND LINGERING SNOW SHOWERS TO THE LEE OF ONTARIO. BY SUNDAY...WE WILL HAVE TO WATCH TO SEE IF A STORM DEVELOPS ALONG THE EASTERN SEABOARD. RIGHT NOW IF IT DOES...IT LOOKS WEAK AND MIGHT HEAD OUT TO SEA...BUT BEARS WATCHING. FOR NOW...WE WILL ASSIGN A SLIGHT CHANCE OF SNOW WITH A MOSTLY CLOUDY SKY. HIGH TEMPERATURES WILL MODERATE BACK CLOSER TO NORMAL...BUT STILL BELOW FREEZING EVERYWHERE ACROSS OUR REGION. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... AS OF 1000 PM...CONDITIONS HAVE IMPROVED TO MVFR OR VFR AT ALL OF OUR TAF SITES. SHOWERS LOOK TO STILL IMPACT MAINLY KPOU AND KPSF WITH OCCASIONAL MVFR CONDITIONS THROUGH ABOUT MIDNIGHT. OTHERWISE...WITH THE POSSIBLE EXCEPTION OF KPSF...WE WILL HAVE MAINLY VFR CONDITIONS THROUGH MONDAY...MVFR AT KPSF. MONDAY AT KALB...AS A LAKE BAND OFF ONTARIO MIGHT IMPACT THE AIRPORT BETWEEN ABOUT 15Z-19Z. WE ASSIGNED A PROB30 FOR IFR SNOW SHOWERS (2SM -SHSN). AT KGFL AND KPSF WE ASSIGNED A VCSH AS THE THREAT OF MVFR SNOW SHOWERS WAS VERY LOW (ONLY ABOUT 25 PERCENT). AGAIN OUTSIDE OF ANY SNOW SHOWER ACTIVITY...THE MAJORITY OF THE TIME SHOULD BE VFR AT ALL TAF SITES MONDAY. AGAIN...A GUSTY WIND COULD CAUSE MECHANICAL TURBULENCE. OUTLOOK... MON NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. TUE: HIGH OPERATIONAL IMPACT. LIKELY SN. TUE NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN. WED: MODERATE OPERATIONAL IMPACT. BREEZY. CHANCE OF SHSN. WED NIGHT: LOW OPERATIONAL IMPACT. BREEZY. THU: NO OPERATIONAL IMPACT. NO SIG WX. THU NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHSN. FRI: NO OPERATIONAL IMPACT. NO SIG WX. && .HYDROLOGY... A COMPLEX STORM SYSTEM WITH MODERATE TO HEAVY QPF WILL MOVE ACROSS THE HSA THROUGH TODAY. MOST AREAS ARE FORECAST TO RECEIVE 1-2 INCHES OF LIQUID EQUIVALENT PRECIPITATION...WITH LOCALLY IN EXCESS OF TWO INCHES. THIS WILL ALLOW FOR SIGNIFICANT RISES ON RIVERS AND STREAMS ON SUNDAY...AS TEMPERATURES RISE ABOVE FREEZING BRIEFLY OVER THE ENTIRE REGION. ISOLATED MINOR FLOODING IS POSSIBLE AND PER COLLABORATION YESTERDAY WITH THE NERFC...THE HSA POINTS THAT GOES ABOVE ACTION STAGE ARE WILLIAMSTOWN /WILM3/...AND GRANVILLE /GVVN6/ AT THIS TIME. SINCE THE POTENTIAL OF WIDESPREAD MINOR FLOODING IS NOT EXPECTED...A FLOOD WATCH HAS NOT BEEN ISSUED AT THIS TIME. LAKE EFFECT SNOWFALL WILL IMPACT LOCATIONS NORTH AND WEST OF THE CAPITAL REGION TONIGHT THROUGH MONDAY IN THE WAKE OF A STRONG COLD FRONT. THEREAFTER...BITTER COLD WEATHER IS EXPECTED NEXT WEEK. SOME FREEZE UP ICE JAMS ARE POSSIBLE ACROSS THE SOUTHWESTERN ADIRONDACKS AND SOUTHERN VERMONT BY LATE IN THE WEEK. OTHERWISE...ICE WILL LIKELY DEVELOP AND INCREASE ACROSS RIVERS AND STREAMS. 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...LAKE EFFECT SNOW ADVISORY FROM 4 AM TO 7 PM EST MONDAY FOR NYZ038>040-082. LAKE EFFECT SNOW ADVISORY UNTIL 9 AM EST MONDAY FOR NYZ032-033. MA...NONE. VT...NONE. && $$ SYNOPSIS...HWJIV/BGM NEAR TERM...HWJIV SHORT TERM...BGM/WASULA LONG TERM...HWJIV AVIATION...HWJIV HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS MIAMI FL
404 AM EST MON JAN 5 2015 .DISCUSSION... A COLD FRONT IS CURRENTLY MAKING ITS WAY TOWARDS SOUTH FLORIDA AS EXPECTED. IT IS CURRENTLY IN CENTRAL FLORIDA. AHEAD OF IT SOME SHOWER ACTIVITY HAS ALREADY DEVELOPED, MAINLY ALONG THE ATLANTIC COASTLINE. THE HRRR DOES SHOW THIS ACTIVITY ENDING OVER THE NEXT COUPLE OF HOURS. SO, CONTINUE WITH SLIGHT CHANCE POPS OVER COASTAL PALM BEACH COUNTY TO COVER ANY SHOWER ACTIVITY THAT PERSISTS. ANOTHER CONCERN WITH THIS LINE OF CONVERGENCE ALONG THE COAST IS WATERSPOUT ACTIVITY. ALTHOUGH THE BOUNDARY IS NOT PROMINENT ON THE GULF COAST, CAN NOT RULE ONE OUT ACROSS ANY OF THE SOUTH FLORIDA WATERS THIS MORNING. COMPARING LAST NIGHTS SOUNDING AND THE WATER VAPOR IMAGERY, THE MOISTURE LOOKS TO BE FAIRLY SHALLOW. THE SOUNDING SHOWS A STRONG CAP IS IN PLACE AT AROUND 800MB. NAM MODEL SOUNDINGS SHOW IT SHOULD HOLD, EVEN WITH THE FRONT APPROACHING. THE WATER VAPOR IMAGERY IS SHOWING THAT THE MOISTURE IS REMAINING MAINLY OVER NORTH FLORIDA AND SOUTH GEORGIA, WITH LITTLE PROGRESSION TO THE SOUTH. SO, THIS WILL LEND CREDENCE TO THE LOW POPS THE MODELS ARE FORECASTING FOR TODAY, WITH A LOW END CHANCE OVER THE A PORTION OF THE CWA THIS AFTERNOON. THE FRONT WILL SLOWLY PROGRESS TO THE SOUTH, THROUGH THE CWA TODAY, AS THE MAIN LOW IS WELL AWAY FROM THE AREA, NORTHEAST OF MAINE, AND PULLING AWAY. MODELS SHOW THE FRONT WILL MAKE IT THROUGH MOST OF SOUTH FLORIDA AND PERHAPS TO THE KEYS BEFORE STALLING OUT. IT WILL THEN SIT FOR THROUGH WEDNESDAY AS A WEAK BOUNDARY, KEEPING A SLIGHT CHANCE OF SHOWERS IN THE FORECAST FOR PORTIONS OF THE CWA UNTIL WEDNESDAY EVENING. EVEN THAT WILL BE MORE OR LESS ALONG THE ATLANTIC COAST AND OVER THE ATLANTIC WATERS. HIGH PRESSURE WILL BUILD IN OVER THE SOUTH EASTERN US, BUT NEVER DIG FAR ENOUGH SOUTH TO PUSH THE FRONT AWAY FROM THE AREA. MEANWHILE, ANOTHER LOW WILL MOVE OUT OF THE ROCKIES TODAY AND QUICKLY MOVE INTO THE PLAINS. MODELS INDICATE IT SHOULD BE OVER THE MISSISSIPPI VALLEY TONIGHT AND THEN APPEAR TO WASH OUT AS IT MOVES ACROSS THE APPALACIANS. MODELS SHOW IT WILL REFORM OFF THE MID ATLANTIC COAST TUESDAY NIGHT AND BEGIN TO INTERACT WITH THE STALLED BOUNDARY. AS IT DOES, AS VERY STRONG HIGH WILL MOVE OUT OF WESTERN CANADA AND INTO THE PLAINS. THIS HIGH WILL WORK WITH THE LOW TO PUSH THE FRONT OUT OF THE AREA WEDNESDAY NIGHT AND WILL MOVE COOLER, DRIER AIR INTO SOUTH FLORIDA BY THURSDAY MORNING. HOWEVER, EVEN THOUGH IT WILL BE A SIGNIFICANT COOL DOWN. IT WILL NOT BE ENOUGH TO WARRANT ANY HEADLINES. LOWS THURSDAY LOOK TO BE IN THE MID 40S FOR THE INTERIOR LAKE REGION TO THE UPPER 50S ALONG THE ATLANTIC COAST. THE GULF COAST LOOKS TO BE IN THE UPPER 40S TO LOW 50S. HIGHS THURSDAY WILL RANGE FROM THE LOW 60S IN THE LAKE REGION TO AROUND 70 IN THE MIAMI AREA. THIS HIGH IS VERY TRANSIENT AND WILL BE GONE BY THE WEEKEND. THIS WILL ALLOW TEMPERATURES TO QUICKLY REBOUND AND COASTAL SHOWERS TO MAKE A RETURN POSSIBLY BY FRIDAY. THE FLOW WILL CONTINUE TO BE EASTERLY, SO THE ATLANTIC COAST LOOKS TO HAVE THE BEST CHANCE FOR SHOWER ACTIVITY. BY THE END OF THE WEEKEND, SOUTH FLORIDA WILL BE BACK UNDER THE WESTERN EDGE OF AN UPPER LEVEL RIDGE AND STILL IN EASTERLY SFC FLOW. MODELS ARE SHOWING A CHANCE FOR SHOWERS ACROSS THE AREA BY SUNDAY. && .AVIATION... ALTHOUGH THE RECENT COMPUTER MODEL GUIDANCE DOES NOT INDICATE MUCH IN THE WAY OF IFR VISIBILITY OR CEILING RESTRICTIONS OR MUCH POTENTIAL FOR WIDESPREAD FOG DEVELOPMENT THIS MORNING...CONDITIONS COULD BE FAVORABLE FOR LOW STRATUS AND/OR AREAS OF FOG AS A COLD FRONT CONTINUES TO MOVE INTO NORTHERN FLORIDA. ALL TAF SITES HAVE BEEN ASSIGNED PERIODS OF MVFR VISIBILITY RESTRICTIONS FROM 09Z TO 12Z THIS MORNING. BRIEF PERIODS OF NEAR IFR CONDITIONS MAY BE POSSIBLE AND WILL HAVE TO AMEND IF/WHEN CONDITIONS WARRANT. REGIONAL WINDS ARE EXPECTED TO BE LIGHT AND SOMEWHAT VARIABLE AT TIMES. && .MARINE... SHOWER ACTIVITY WILL BE POSSIBLE TODAY AS A COLD FRONT SLOWLY MOVES THROUGH THE AREA. WINDS WILL SLOWLY TURN TO THE NORTH AND NORTHEAST TODAY. THERE IS A SLIGHT CHANCE OF A WATERSPOUT, MAINLY ALONG A CONVERGENCE LINE ALONG THE ATLANTIC COAST THIS MORNING. THE FRONT WILL STALL JUST TO THE SOUTH, KEEP A SLIGHT CHANCE OF SHOWERS THROUGH WEDNESDAY. WEDNESDAY NIGHT, A STRONG HIGH WILL BUILD IN, BRINGING BREEZY CONDITIONS AND BUILDING SEAS FOR THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 80 70 80 67 / 30 20 20 20 FORT LAUDERDALE 81 72 80 69 / 20 20 20 10 MIAMI 82 71 82 69 / 20 20 10 10 NAPLES 80 65 81 64 / 10 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...13/SI LONG TERM....13/SI AVIATION...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
1247 AM EST MON JAN 5 2015 .AVIATION... ALTHOUGH THE RECENT COMPUTER MODEL GUIDANCE DOES NOT INDICATE MUCH IN THE WAY OF IFR VISIBILITY OR CEILING RESTRICTIONS OR MUCH POTENTIAL FOR WIDESPREAD FOG DEVELOPMENT THIS MORNING...CONDITIONS COULD BE FAVORABLE FOR LOW STRATUS AND/OR AREAS OF FOG AS A COLD FRONT CONTINUES TO MOVE INTO NORTHERN FLORIDA. ALL TAF SITES HAVE BEEN ASSIGNED PERIODS OF MVFR VISIBILITY RESTRICTIONS FROM 09Z TO 12Z THIS MORNING. BRIEF PERIODS OF NEAR IFR CONDITIONS MAY BE POSSIBLE AND WILL HAVE TO AMEND IF/WHEN CONDITIONS WARRANT. REGIONAL WINDS ARE EXPECTED TO BE LIGHT AND SOMEWHAT VARIABLE AT TIMES. 60 && .PREV DISCUSSION... /ISSUED 721 PM EST SUN JAN 4 2015/ UPDATE...IT SURE DOESN`T FEEL LIKE JANUARY! A DEWPOINT OF 72F AT THE OFFICE RIGHT NOW. THIS RATHER STEAMY AIRMASS ALONG WITH JUST SLIGHT CONVERGENCE IN SURFACE WINDS (SE WINDS ENCOUNTERING SW WINDS IN THE LAKE REGION) HAS ALLOWED FOR A BROKEN BAND OF MODERATE TO HEAVY SHOWERS TO DEVELOP FROM SOUTHEASTERN HENDRY COUNTY EXTENDING NORTHEAST TO LAKE OKEECHOBEE.THE LATEST RUN OF THE HRRR INITIALIZED WELL, DEPICTING SHOWER ACTIVITY ACROSS THIS REGION AND SHOWS THESE SHOWERS DECAYING THROUGH MIDNIGHT. THIS SEEMS REASONABLE WITH THE LOSS OF DAYTIME HEATING. SO THE ONLY UPDATE TO THE FORECAST WAS TO ADD THE ONGOING ISOLATED SHOWERS ACROSS THIS REGION FOR THE NEXT FEW HOURS. /GREGORIA PREV DISCUSSION... /ISSUED 654 PM EST SUN JAN 4 2015/ AVIATION... MAINLY VFR CONDITIONS TO PREVAIL THROUGH THE PERIOD. MAINLY LIGHT SOUTHERLY WINDS WILL TRANSITION EAST-SOUTHEASTERLY THROUGH THE NIGHT AS A COLD FRONT APPROACHES THE AREA FROM THE NORTH. FRONT SHOULD EASE INTO SOUTH FLORIDA TOWARD THE LAST FEW HOURS OF THIS TAF CYCLE TURNING WINDS AROUND TO THE NORTHEAST. A FEW SHOWERS MAY BRIEFLY AFFECT THE TAF SITES AS THE FRONT APPROACHES BUT COVERAGE SHOULD BE TOO SPARSE TO MENTION IN TAFS FOR NOW. MAIN CONCERN FOR FOG DEVELOPMENT WILL BE ACROSS THE NORTHWEST INTERIOR AND MAY BRIEFLY AFFECT KAPF. PLACED A TEMPO FOR MVFR VSBY FROM 09Z-13Z AS IT LOOKS LIKE BEST COVERAGE FOR FOG WILL REMAIN EAST OF KAPF. PREV DISCUSSION... /ISSUED 249 PM EST SUN JAN 4 2015/ SHORT TERM (TONIGHT THROUGH WEDNESDAY)... LARGE AND DEEP-LAYERED SUBTROPICAL HIGH PRESSURE EXTENDING FROM THE BAHAMAS ACROSS SOUTH FLORIDA WILL PERSIST THROUGH TUESDAY, THEN FINALLY GIVE WAY TO AMPLIFYING EASTERN U.S. TROUGH BY WEDNESDAY. THE RIDGE WILL KEEP THE STRONG/SEVERE TSTMS CURRENTLY OVER THE FLORIDA PANHANDLE FROM REACHING OUR PART OF THE STATE. THE COLD FRONT ASSOCIATED WITH THESE TSTMS WILL MOVE DOWN THE STATE TONIGHT, REACHING THE LAKE OKEECHOBEE AREA SHORTLY AFTER SUNRISE MONDAY. AHEAD OF THE FRONT, A FEW LIGHT SHOWERS (SIMILAR TO WHAT WE`RE SEEING THIS AFTERNOON) ARE NOT TOTALLY OUT OF THE QUESTION BUT NOT HIGH ENOUGH PROBABILITY (10%) TO INCLUDE IN FORECAST. AS IS TYPICAL WITH NIGHTTIME FRONTS NORTH OF LAKE OKEECHOBEE, PATCHY FOG IS EXPECTED AND COULD BE DENSE IN A FEW AREAS OF THE INTERIOR AND WEST. SHORT RANGE ENSEMBLE FORECASTS ARE NOT SHOWING HIGH PROBABILITIES OF DENSE FOG, BUT FEEL THIS IS UNDERDONE AND WE MAY END UP WITH AREAS OF FOG OVER THE EVERGLADES. THIS IS WHAT WE`LL DEPICT FOR TONIGHT. THE FRONT WILL MOVE INTO SOUTH FLORIDA ON MONDAY, BUT LIKELY STALL OVER THE EXTREME SOUTHERN PORTION OF THE AREA BY MONDAY NIGHT AS THE STRONG RIDGE HELPS TO PUT THE BRAKES ON ANY SOUTHWARD PROGRESS OF THE FRONT. ONLY SLIGHT COOLING BEHIND THE FRONT (NEAR 80 INSTEAD OF MID 80S PALM BEACHES AND LAKE AREA) WITH NE WINDS PROVIDING A SLIGHT CHANCE OF SHOWERS EASTERN METRO AREAS. FRONT WILL BE DIFFUSE ON TUESDAY BUT ENOUGH LINGERING MOISTURE TO KEEP IN A PESKY 20/30% CHANCE OF SHOWERS AREA-WIDE. ONLY A COUPLE OF DEGREES COOLER FOR HIGH TEMPERATURES, BUT STILL AROUND 80 TO THE LOWER 80S ON TUESDAY. BY WEDNESDAY, THINGS BEGIN TO CHANGE AS A STRONGER FRONT MOVES DOWN THE PENINSULA IN RESPONSE TO A DEEPENING EASTERN U.S. TROUGH. MODELS NOT SHOWING MUCH IN THE WAY OF LOW-LEVEL CONVERGENCE AHEAD OF THIS NEXT FRONT, THEREFORE SHOWER CHANCES WILL REMAIN ON THE LOW SIDE (LESS THAN 20%) DURING THE DAY ON WEDNESDAY AS HIGH TEMPS STILL MANAGE TO REACH THE MID 70S TO AROUND 80. LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)... THE FRONT WILL MOVE THROUGH SOUTH FLORIDA WEDNESDAY NIGHT, USHERING IN MUCH COOLER (BUT NOT UNSEASONABLY COLD) AIR. AIR MASS BEHIND THIS FRONT IS PLENTY COLD, BUT GLOBAL MODELS AGREE IN SHOWING THE ARCTIC HIGH PRESSURE CENTER BEHIND THE FRONT TO SLIDE MORE EAST THAN SOUTH, GIVING SOUTH FLORIDA MORE OF A GLANCING BLOW THAN A STRAIGHT SHOT OF COLD AIR. CONSENSUS OF MODEL SOLUTIONS (INCLUDING ENSEMBLES) SHOW LOW TEMPERATURES THURSDAY AND FRIDAY MORNINGS RANGING FROM THE MID 40S WEST OF LAKE OKEECHOBEE TO NEAR 60 EAST COAST, NOT TOO FAR FROM EARLY JANUARY NORMALS). THE SHALLOW NATURE OF THIS FRONT ALSO MEANS THAT INSTEAD OF THE TYPICAL CLEARING BEHIND STRONG FRONTS, WE WILL LIKELY SEE AN EXTENDED PERIOD OF CLOUDS AND SCATTERED SHOWERS, PARTICULARLY EASTERN METRO AREAS. THIS COULD LEAD TO LOWER MAX TEMPERATURES ON THURSDAY AND FRIDAY THAN WHAT IS CURRENTLY FORECAST. MODELS SHOW PLENTY OF MOISTURE HANGING AROUND THROUGH NEXT WEEKEND, SO IT LOOKS LIKE A RATHER GLOOMY SECOND HALF OF THE WEEK INTO NEXT WEEKEND FOR SOUTH FLORIDA. MARINE... AFTER SOME HIGHER WIND GUSTS TODAY, WINDS DECREASE TONIGHT WITH SUBSIDING SEAS. A BRIEF SURGE IN NORTHEAST WINDS BEHIND THE FRONT ON MONDAY AND MONDAY NIGHT, FOLLOWED BY LIGHT E-NE WINDS TUESDAY INTO WEDNESDAY. THE NEXT FRONT ON WEDNESDAY WILL BE FOLLOWED BY MUCH STRONGER NORTH WINDS, WITH WINDS NEAR 25 KT LIKELY WITH HIGHER GUSTS AND ROUGH SEAS LASTING THROUGH THURSDAY. CLIMATE... THIS MORNING`S LOW TEMPERATURES AT ALL FOUR MAIN CLIMATE SITES ARE ON PACE TO EITHER TIE OR BREAK HIGH MINIMUM RECORDS FOR THE DATE: MIA: AM LOW 76/RECORD 76 (1971) FLL: AM LOW 75/RECORD 74 (2007) PBI: AM LOW 76/RECORD 73 (2007) APF: AM LOW 70/RECORD 68 (1973) && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 80 70 80 67 / 20 20 20 20 FORT LAUDERDALE 81 72 80 69 / 20 20 10 20 MIAMI 82 71 81 69 / 20 20 10 20 NAPLES 80 65 80 65 / 10 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...60/BD LONG TERM....13/SI AVIATION...60/BD
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1118 PM CST SUN JAN 4 2015 .UPDATE... ISSUED AT 904 PM CST SUN JAN 4 2015 00Z MODELS ARE BEGINNING TO TRICKLE IN AND ARE IN FAIRLY GOOD AGREEMENT WITH THE CURRENT FORECAST. HI RESOLUTION SHORT TERM MODELS ARE STILL DIFFERING SOME ON THE TIMING. THE RAP IS A BIT QUICKER THAN THE HRRR...BUT THE LATEST RUN OF THE HRRR IS TRENDING CLOSER TO THE PROGRESSIVE RAP. WITH THE STRONG FORCING AND VERY EFFICIENT ATMOSPHERE FOR PRODUCING DENDRITES...EXPECT CONDITIONS TO RAPIDLY DETERIORATE LATE MONDAY MORNING INTO MONDAY AFTERNOON AS BAND OF SNOW DEVELOPS ACROSS THE AREA. CONSIDERED TRENDING THE WINTER STORM WARNING SLIGHTLY EARLIER...BUT ENOUGH UNCERTAINTY EXISTS RIGHT NOW WITH THE PRECISE TIMING THAT IT IS BEST TO LEAVE THINGS AS IT IS. WITH THE DRY NATURE OF THE SNOW AND THE STRONG WINDS AT BOTH THE ONSET AND THEN AGAIN AT THE END OF THE EVENT...TRAVEL CONDITIONS WILL BE QUITE POOR. THOSE WITH TRAVEL PLANS MONDAY AFTERNOON INTO MONDAY NIGHT SHOULD MAKE ALTERNATIVE PLANS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 258 PM CST SUN JAN 4 2015 TODAY LOOKS LIKE THE CALM BEFORE THE STORM. ALL EYES CONTINUE TO WATCH PROGRESSION OF SHORTWAVE ENERGY JUST NOW BEGINNING TO ENTER THE WESTERN COAST OF BRITISH COLUMBIA. MEANWHILE...AN INITIAL SHORTWAVE ACROSS MONTANA THIS MORNING CONTINUES TO DRIFT SOUTHEAST LATE THIS AFTERNOON. IMPACTS WITH THIS WAVE LOOK TO BE MINIMAL...WITH MUCH OF THE MID-UPR CLOUDS EXPECTED TO STAY SOUTHEAST OF THE REGION. FOR TONIGHT...SURFACE HIGH PRESSURE WILL DROP SOUTHEAST INTO THE AREA. LIGHT WINDS SHOULD SETUP A RATHER COLD NIGHT TONIGHT. OVERNIGHT LOWS WILL FALL BELOW -10 IN MANY LOCATIONS...AND WOULD NOT BE SURPRISED TO SEE A FEW SPOTS DROP TOWARDS -15 OR LOWER. THE LIGHT WINDS WILL PRECLUDE ANY EXTREME WIND CHILL DROP...BUT ANTICIPATING A LIGHT NORTHERLY WIND OVER THE NORTHEASTERN THIRD OF THE CWA TO KEEP WIND CHILL ADVISORY CONDITIONS LIKELY OVERNIGHT. MONDAY WILL START OFF BITTERLY COLD...BUT DECEPTIVELY SUNNY. HI-RES MODELS CONTINUE TO TREND SLIGHTLY FURTHER SOUTH WITH THE TRACK OF THE CLIPPER HEADING INTO THE AREA...RAISING CONFIDENCE IN NUDGING THE HIGHER SNOW TOTALS FURTHER SOUTHWEST. THROUGH THE MORNING...WE WILL BEGIN TO SEE A RAPID INCREASE IN MID-LVL CLOUDS AS MID-LVL WARM ADVECTION BEGINS. A STRONG LOW-LVL FRONTAL CIRCULATION IS EXPECTED TO DEVELOP QUICKLY BY MID-DAY...WITH RAPID TOP-DOWN SATURATION DEVELOPING INTO A FAIRLY BROAD AND ELONGATED AREA OF SNOW ACROSS THE FORECAST AREA. AS ALLUDED TO IN PREVIOUS DISCUSSIONS...THERE IS A HIGH LIKELIHOOD OF AN ENHANCED BAND OF SNOW WITHIN THIS BROAD AREA...WHERE SNOWFALL RATES MAY BE EXTREMELY HIGH. WITH SNOW DRAMATICALLY INCREASING IN THE AFTERNOON AND CONTINUING INTO THE EARLY EVENING...TOTAL SNOWFALL COULD APPROACH 5 TO LOCALLY 8 OR MORE INCHES OF SNOW IN THE HIGHEST CORRIDOR FROM NEAR DE SMET...THROUGH SIOUX FALLS AND FURTHER SOUTHEAST TOWARDS STORM LAKE AND SPENCER. GIVEN DRY AIR ALONG THE NORTHEASTERN FRINGES OF THIS SYSTEM...THE NORTHEASTERN EDGE OF SNOW MAY BE MORE SHARPLY DEFINED THAN INDICATED IN CURRENT GRIDS. SURFACE WINDS WILL COMPLICATE MATTERS DURING THE DAY...AS PERSISTENT SOUTHEAST TO EAST WINDS MAY GUST AS HIGH AS 30 MPH AT TIMES. ONCE THE SURFACE LOW PASSES EARLY IN THE EVENING...WINDS WILL TURN BACK TO THE NORTHWEST WITH THE HIGHEST GUSTS FOCUSED ALONG THE MISSOURI RIVER CHANNEL. AS FAR AS HEADLINES ARE CONCERNED...CONFIDENCE HIGH ENOUGH TO CONVERT MOST OF THE WATCH INTO A WARNING. THE CONCERN WOULD BE IN LYON AND LINCOLN COUNTIES IN MINNESOTA WHERE THE POTENTIAL FOR A TIGHTER NE SNOW GRADIENT MAY SPLIT THE COUNTIES. GIVEN THE POTENTIAL FOR THIS WAVE TO DIG SLIGHTLY FURTHER...WILL LEAVE AND EXPAND THE WATCH SLIGHTLY FURTHER SOUTHWEST TO CORRESPOND WITH THE INCREASE IN SNOW AMOUNTS FORECAST TODAY AND POSSIBILITY OF FURTHER WARNING EXPANSION SOUTHWARD. TRAVEL SHOULD BE ATTEMPTED WITH EXTREME CAUTION MONDAY AFTERNOON INTO MONDAY EVENING...GIVEN THE RAPID DETERIORATION OF CONDITIONS FROM THE FIRST HALF TO THE SECOND HALF OF THE DAY. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 258 PM CST SUN JAN 4 2015 THE COLD AIR SURGE BEHIND THE SNOW SYSTEM MONDAY NIGHT WILL BE OUTDONE BY A REINFORCING ARCTIC SURGE TUESDAY NIGHT AS A STRONG CANADIAN WAVE DIGS TOWARD THE GREAT LAKES. TUESDAY WILL BE COLD ENOUGH WITH MOSTLY SINGLE DIGIT HIGHS AND SOME CLOUDS LINGERING BETWEEN THE EXITED STORM AND THE APPROACHING MONSTER ARCTIC HIGH. THE SURGE WILL ARRIVE TUESDAY NIGHT WITH WINDS PICKING UP FROM THE RELATIVELY TAME TUESDAY BREEZE. ALONG WITH THIS SURGE WILL COME SOME BLOWING OF THE FRESH SNOW...POSSIBLY ENOUGH FOR ADVISORIES JUST FOR THAT...AND WIND CHILLS LIKELY DIVING BELOW THE WARNING LEVEL...THAT IS 35 TO 45 BELOW...NORTHEAST AT LEAST...BY WEDNESDAY MORNING. WINDS SHOULD THEN DECREASE SLOWLY DURING THE DAY WEDNESDAY AS THE 1060MB HIGH ARRIVES OVER WESTERN SOUTH DAKOTA...BUT ACTUAL HIGH TEMPERATURES WILL BE BELOW ZERO IN MOST OF THE AREA. THE SURGE BY THE WAY SHOULD CLEAR OUT SKIES PRETTY WELL WITH THAT HIGH GETTING CLOSE. A VERY FAST WARMUP SHOULD TAKE PLACE WEDNESDAY NIGHT WITH THE NEXT WAVE AND FRONT COMING IN EARLY THURSDAY. THIS WARMUP WILL BE SO FAST THAT IT WILL GET IN ONLY A LIMITED WAY TO THE SURFACE. IN FACT...THE THURSDAY COLD FRONT WILL BE MORE LIKE AN OCCLUSION AS A LESS BITING COLD AIR PLUNGE ARRIVES. AFTER HIGHS IN THE TEENS TO MID 20S THURSDAY...FRIDAY WILL BRING HIGHS IN THE SINGLE DIGITS RANGING TO SOME TEENS SOUTHWEST...ALL ABOVE ZERO. SATURDAY AND SUNDAY WILL BE BACK INTO THE TEENS TO LOWER 20S FOR HIGHS...BELOW NORMAL BUT NOT AS MUCH AS EARLY THIS WEEK. WILL KEEP OUT MENTION OF ANY LIGHT SNOW FOR WEDNESDAY NIGHT INTO THURSDAY...WITH THE WARMING BEING TOO FAST TO POOL ENOUGH MOISTURE. THERE COULD THEN BE SOME ABOUT FRIDAY OR SATURDAY AS SOME SLOW WARM ADVECTION BEGINS ALOFT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1113 PM CST SUN JAN 4 2015 THERE IS AN AREA OF UPPER END MVFR CEILINGS MOVING SOUTHEASTWARD ACROSS THE SOUTHERN HALF OF THE SIOUX FALLS FORECAST AREA AT THIS TIME. THIS AREA OF CLOUDS IS PRIMARILY AFFECTING THE KFSD TAF SITE. DUE TO THE AMOUNT OF HIGH CLOUDS...IT IS DIFFICULT TO TELL IF THESE CLOUDS WILL ACTUALLY MOVE INTO...OUR EXPAND INTO KSUX. AT ANY RATE...DID ACCOUNT FOR SOME CEILINGS NEAR 3000 FEET AGL FOR SIOUX FALLS FOR A SHORT PERIOD OF TIME...AND KSUX WILL BE MONITORED. OTHERWISE THE FORECAST AREA WILL BE VFR UNTIL MONDAY MORNING WHEN A STRONG...VIGOROUS SYSTEM MOVES SQUARELY INTO OUR REGION. THE SURFACE LOW TRACKS FROM SOUTHEAST MT TO SOUTH CENTRAL SD MONDAY AFTERNOON...WITH AN ATTENDANT WARM FRONT JUTTING SOUTHEASTWARD AHEAD OF THE LOW. THEREFORE SNOWFALL WILL RAPIDLY DEVELOP AND EXPAND ALONG AND EAST OF THE WARM FRONT AFFECTING NEARLY ALL OF OUR FORECAST AREA. MID AND UPPER LEVEL DYNAMICS CONTINUES TO BE VERY STRONG...WITH MID LEVEL FRONTOGENESIS IN NO SHORT SUPPLY...WITH SOME INSTABILITY NOTED ABOVE THE FRONTOGENETIC LAYER. THEREFORE BELIEVE THAT WIDESPREAD IFR TO LIFR CONDITIONS WILL PREVAIL FOR AROUND A 6 TO 8 PERIOD LATE MONDAY MORNING THROUGH EARLY MONDAY EVENING...AFFECTING THE KHON...KFSD AND KSUX TAF SITES. CONDITIONS WILL IMPROVE MONDAY EVENING...BUT WILL HAVE TO WATCH FOR THE THREAT OF SOME PATCHY BLOWING SNOW. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR SDZ038-053-054-061-066-070-071. WINTER STORM WARNING FROM NOON MONDAY TO MIDNIGHT CST MONDAY NIGHT FOR SDZ039-040-055-056-062-067. WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR SDZ038>040-052>056- 061-062-067. MN...WINTER STORM WARNING FROM NOON MONDAY TO MIDNIGHT CST MONDAY NIGHT FOR MNZ071-072-080-081-089-090-097-098. WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR MNZ071-072-080-081- 089-090-097-098. IA...WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH MONDAY EVENING FOR IAZ020-031-032. WINTER STORM WARNING FROM NOON MONDAY TO MIDNIGHT CST MONDAY NIGHT FOR IAZ001>003-012>014-021-022. WIND CHILL ADVISORY UNTIL NOON CST MONDAY FOR IAZ001>003-012>014- 021-022-032. NE...NONE. && $$ UPDATE... SHORT TERM... LONG TERM...DUX AVIATION...MJ
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
309 AM EST MON JAN 5 2015 .SHORT TERM (TODAY AND TONIGHT)... THE MAIN FORECAST PROBLEM OF THE DAY IS HOW QUICKLY CLOUD COVER WILL ERODE ACROSS THE AREA. THE GFS IS QUICKER THAN THE NAM AND HRRR TO CLEAR OUT THE CLOUDS...AND WILL LEAN TOWARD THE SLOWER SOLUTION WHICH TENDS TO OCCUR MORE OFTEN IN THIS PATTERN. STILL...WE SHOULD HAVE MOSTLY SUNNY SKIES EVERYWHERE BY THE AFTERNOON. WITH 850 MB COLD ADVECTION PERSISTING THROUGH THE DAY...HIGHS WILL BE IN THE 30S TO AROUND 40 SOUTH. A SOUTHWARD DIP OF THE JET STREAM AND A SHORTAVE TROUGH PASSING ACROSS THE GREAT LAKES/OHIO VALLEY TONIGHT MAY BRING SOME HIGH CLOUDS TO NORTHERN AREAS AFTER MIDNIGHT. .LONG TERM (TUESDAY THROUGH SUNDAY)... QUIET WEATHER WILL BE THE STORY FOR MOST OF THE LONG TERM FORECAST. ONLY A COUPLE OF ITEMS OF NOTE UPCOMING...COLD FRONT ON WEDNESDAY AND THE NEXT SYSTEM MOVING THROUGH OVER THE WEEKEND. COLD FRONT...COLD FRONT DOESN`T REALLY POSE MUCH IN THE WAY OF PRECIP AS IT WILL BE RELATIVELY MOISTURE STARVED, BUT THERE IS A CHANCE THAT IT`S STRONG ENOUGH TO SQUEEZE OUT WHAT LITTLE MOISTURE THERE IS IN SOME PLACES. SO HAVE CONTINUED WITH MENTION OF 10 PERCENT CHANCE OF FLURRIES IN NORTHEAST TN/ SOUTHWEST VA. AFTER THE FRONT COMES THROUGH TEMPS WILL REACH THE COLDEST WE`VE SEEN IN QUITE SOME TIME, LOOKS LIKE THE LAST TIME MANY OF LOCATIONS WILL HAVE SEEN TEMPS THIS COLD WAS JANUARY 30TH OF LAST YEAR. WEEKEND SYSTEM...NOT MUCH CHANGE TO THE FORECAST IN THIS TIME FRAME, MODELS ARE VERY SLOWLY TRYING TO COME INTO AGREEMENT WITH WHAT WILL HAPPEN WITH THIS SYSTEM. BUT AT THIS TIME THE MODEL SPREAD IS WIDE ENOUGH THAT IT LEADS TO RELATIVELY LOW CONFIDENCE FOR THIS SYSTEM. LOOKS LIKE TEMPS WILL BE COLD ENOUGH OVERNIGHT ACROSS MUCH OF THE AREA THAT IT`S WORTH MENTIONING THAT SOME LIGHT SNOW WILL BE POSSIBLE ACROSS MUCH OF THE FORECAST AREA. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 40 26 50 27 / 0 0 10 10 KNOXVILLE MCGHEE TYSON AIRPORT, TN 38 25 48 26 / 0 0 10 10 OAK RIDGE, TN 37 24 46 26 / 0 0 10 10 TRI CITIES AIRPORT, TN 34 22 44 25 / 0 0 10 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DGS/ABM
AREA FORECAST DISCUSSION
NWS MIAMI FL
953 AM EST MON JAN 5 2015 .UPDATE... CURRENT ANALYSIS SHOWS DEEP LAYER RIDGE STRETCHING ACROSS THE EXTREME SOUTHERN PORTION OF THE PENINSULA WITH A WEAK COLD FRONT NEAR THE SOUTHERN SHORES OF LAKE OKEECHOBEE INCLUDING EXTREME NORTHERN PALM BEACH AND HENDRY COUNTIES ALONG WITH GLADES COUNTY. THE FRONT IS VERY SHALLOW AND IS MARKED BY A NEAR SOLID DECK OF LOW STRATUS BEHIND THE LEADING EDGE OF THE BOUNDARY. THE FRONT WILL NOT MAKE FURTHER PROGRESS SOUTHWARD STALLING NEAR ITS CURRENT POSITION AND THEN BECOMING DIFFUSE AS THE MAIN UPPER TROUGH LIFTS WELL TO THE NORTHEAST. THIS WILL LEAVE MOST OF SOUTH FLORIDA IN THE WARM SECTOR THIS AFTERNOON AND WITH DEW POINTS IN THE UPPER 60S TO AROUND 70, HIGH RESOLUTION SHORT TERM MODEL GUIDANCE SUGGEST A FEW SHOWERS OVER THE INTERIOR AND EAST COASTAL ZONES. THE 12Z MFL SOUNDING ALSO SHOWS THE LOW LEVEL MOISTURE INCREASING FROM YESTERDAY BUT THE STRONG SUBSIDENCE CAP WITH ITS BASE AT 7-8K WILL KEEP THE SHOWERS LOW TOPPED. KOB && .PREV DISCUSSION... /ISSUED 624 AM EST MON JAN 5 2015/ AVIATION... LIGHT TO MODERATE SHOWERS CONTINUE IN THE VICINITY OF ALL THE ATLANTIC COAST TERMINALS AROUND 11Z AND ARE NEARLY STATIONARY. BRIEF PERIODS OF NEAR MVFR CEILINGS ARE POSSIBLE THROUGH ABOUT 13Z AS THE SHOWERS ARE NEARLY STATIONARY. OTHERWISE...MAINLY VFR CONDITIONS EXPECTED LATER THIS MORNING AND THIS AFTERNOON. WINDS THIS MORNING ARE EXPECTED TO BE LIGHT AND VARIABLE WITH NORTHEASTERLY WINDS BUILDING INTO THE REGION AROUND 18Z AHEAD OF A COLD FRONT IN NORTH CENTRAL FLORIDA. PREV DISCUSSION... /ISSUED 404 AM EST MON JAN 5 2015/ DISCUSSION... A COLD FRONT IS CURRENTLY MAKING ITS WAY TOWARDS SOUTH FLORIDA AS EXPECTED. IT IS CURRENTLY IN CENTRAL FLORIDA. AHEAD OF IT SOME SHOWER ACTIVITY HAS ALREADY DEVELOPED, MAINLY ALONG THE ATLANTIC COASTLINE. THE HRRR DOES SHOW THIS ACTIVITY ENDING OVER THE NEXT COUPLE OF HOURS. SO, CONTINUE WITH SLIGHT CHANCE POPS OVER COASTAL PALM BEACH COUNTY TO COVER ANY SHOWER ACTIVITY THAT PERSISTS. ANOTHER CONCERN WITH THIS LINE OF CONVERGENCE ALONG THE COAST IS WATERSPOUT ACTIVITY. ALTHOUGH THE BOUNDARY IS NOT PROMINENT ON THE GULF COAST, CAN NOT RULE ONE OUT ACROSS ANY OF THE SOUTH FLORIDA WATERS THIS MORNING. COMPARING LAST NIGHTS SOUNDING AND THE WATER VAPOR IMAGERY, THE MOISTURE LOOKS TO BE FAIRLY SHALLOW. THE SOUNDING SHOWS A STRONG CAP IS IN PLACE AT AROUND 800MB. NAM MODEL SOUNDINGS SHOW IT SHOULD HOLD, EVEN WITH THE FRONT APPROACHING. THE WATER VAPOR IMAGERY IS SHOWING THAT THE MOISTURE IS REMAINING MAINLY OVER NORTH FLORIDA AND SOUTH GEORGIA, WITH LITTLE PROGRESSION TO THE SOUTH. SO, THIS WILL LEND CREDENCE TO THE LOW POPS THE MODELS ARE FORECASTING FOR TODAY, WITH A LOW END CHANCE OVER THE A PORTION OF THE CWA THIS AFTERNOON. THE FRONT WILL SLOWLY PROGRESS TO THE SOUTH, THROUGH THE CWA TODAY, AS THE MAIN LOW IS WELL AWAY FROM THE AREA, NORTHEAST OF MAINE, AND PULLING AWAY. MODELS SHOW THE FRONT WILL MAKE IT THROUGH MOST OF SOUTH FLORIDA AND PERHAPS TO THE KEYS BEFORE STALLING OUT. IT WILL THEN REMAIN THROUGH WEDNESDAY AS A WEAK BOUNDARY, KEEPING A SLIGHT CHANCE OF SHOWERS IN THE FORECAST FOR PORTIONS OF THE CWA UNTIL WEDNESDAY EVENING. EVEN THAT WILL BE MORE OR LESS ALONG THE ATLANTIC COAST AND OVER THE ATLANTIC WATERS. HIGH PRESSURE WILL BUILD IN OVER THE SOUTH EASTERN US, BUT NEVER DIG FAR ENOUGH SOUTH TO PUSH THE FRONT AWAY FROM THE AREA. MEANWHILE, ANOTHER LOW WILL MOVE OUT OF THE ROCKIES TODAY AND QUICKLY MOVE INTO THE PLAINS. MODELS INDICATE IT SHOULD BE OVER THE MISSISSIPPI VALLEY TONIGHT AND THEN APPEAR TO WASH OUT AS IT MOVES ACROSS THE APPALACHIANS. MODELS SHOW IT WILL REFORM OFF THE MID ATLANTIC COAST TUESDAY NIGHT AND BEGIN TO INTERACT WITH THE STALLED BOUNDARY. AS IT DOES, AS VERY STRONG HIGH WILL MOVE OUT OF WESTERN CANADA AND INTO THE PLAINS. THIS HIGH WILL WORK WITH THE LOW TO PUSH THE FRONT OUT OF THE AREA WEDNESDAY NIGHT AND WILL MOVE COOLER, DRIER AIR INTO SOUTH FLORIDA BY THURSDAY MORNING. HOWEVER, EVEN THOUGH IT WILL BE A SIGNIFICANT COOL DOWN, IT WILL NOT BE ENOUGH TO WARRANT ANY HEADLINES. LOWS THURSDAY LOOK TO BE IN THE MID 40S FOR THE INTERIOR LAKE REGION TO THE UPPER 50S ALONG THE ATLANTIC COAST. THE GULF COAST LOOKS TO BE IN THE UPPER 40S TO LOW 50S. HIGHS THURSDAY WILL RANGE FROM THE LOW 60S IN THE LAKE REGION TO AROUND 70 IN THE MIAMI AREA. THIS HIGH IS VERY TRANSIENT AND WILL BE GONE BY THE WEEKEND. THIS WILL ALLOW TEMPERATURES TO QUICKLY REBOUND AND COASTAL SHOWERS TO MAKE A RETURN POSSIBLY BY FRIDAY. THE FLOW WILL CONTINUE TO BE EASTERLY, SO THE ATLANTIC COAST LOOKS TO HAVE THE BEST CHANCE FOR SHOWER ACTIVITY. BY THE END OF THE WEEKEND, SOUTH FLORIDA WILL BE BACK UNDER THE WESTERN EDGE OF AN UPPER LEVEL RIDGE AND STILL IN EASTERLY SFC FLOW. MODELS ARE SHOWING A CHANCE FOR SHOWERS ACROSS THE AREA BY SUNDAY. AVIATION... ALTHOUGH THE RECENT COMPUTER MODEL GUIDANCE DOES NOT INDICATE MUCH IN THE WAY OF IFR VISIBILITY OR CEILING RESTRICTIONS OR MUCH POTENTIAL FOR WIDESPREAD FOG DEVELOPMENT THIS MORNING...CONDITIONS COULD BE FAVORABLE FOR LOW STRATUS AND/OR AREAS OF FOG AS A COLD FRONT CONTINUES TO MOVE INTO NORTHERN FLORIDA. ALL TAF SITES HAVE BEEN ASSIGNED PERIODS OF MVFR VISIBILITY RESTRICTIONS FROM 09Z TO 12Z THIS MORNING. BRIEF PERIODS OF NEAR IFR CONDITIONS MAY BE POSSIBLE AND WILL HAVE TO AMEND IF/WHEN CONDITIONS WARRANT. REGIONAL WINDS ARE EXPECTED TO BE LIGHT AND SOMEWHAT VARIABLE AT TIMES. MARINE... SHOWER ACTIVITY WILL BE POSSIBLE TODAY AS A COLD FRONT SLOWLY MOVES THROUGH THE AREA. WINDS WILL SLOWLY TURN TO THE NORTH AND NORTHEAST TODAY. THERE IS A SLIGHT CHANCE OF A WATERSPOUT, MAINLY ALONG A CONVERGENCE LINE ALONG THE ATLANTIC COAST THIS MORNING. THE FRONT WILL STALL JUST TO THE SOUTH, KEEP A SLIGHT CHANCE OF SHOWERS THROUGH WEDNESDAY. WEDNESDAY NIGHT, A STRONG HIGH WILL BUILD IN, BRINGING BREEZY CONDITIONS AND BUILDING SEAS FOR THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 80 70 80 67 / 30 20 20 20 FORT LAUDERDALE 81 72 80 69 / 30 20 20 10 MIAMI 82 71 82 69 / 30 20 10 10 NAPLES 80 65 81 64 / 10 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MIAMI FL
624 AM EST MON JAN 5 2015 .AVIATION... LIGHT TO MODERATE SHOWERS CONTINUE IN THE VICINITY OF ALL THE ATLANTIC COAST TERMINALS AROUND 11Z AND ARE NEARLY STATIONARY. BRIEF PERIODS OF NEAR MVFR CEILINGS ARE POSSIBLE THROUGH ABOUT 13Z AS THE SHOWERS ARE NEARLY STATIONARY. OTHERWISE...MAINLY VFR CONDITIONS EXPECTED LATER THIS MORNING AND THIS AFTERNOON. WINDS THIS MORNING ARE EXPECTED TO BE LIGHT AND VARIABLE WITH NORTHEASTERLY WINDS BUILDING INTO THE REGION AROUND 18Z AHEAD OF A COLD FRONT IN NORTH CENTRAL FLORIDA. && .PREV DISCUSSION... /ISSUED 404 AM EST MON JAN 5 2015/ DISCUSSION... A COLD FRONT IS CURRENTLY MAKING ITS WAY TOWARDS SOUTH FLORIDA AS EXPECTED. IT IS CURRENTLY IN CENTRAL FLORIDA. AHEAD OF IT SOME SHOWER ACTIVITY HAS ALREADY DEVELOPED, MAINLY ALONG THE ATLANTIC COASTLINE. THE HRRR DOES SHOW THIS ACTIVITY ENDING OVER THE NEXT COUPLE OF HOURS. SO, CONTINUE WITH SLIGHT CHANCE POPS OVER COASTAL PALM BEACH COUNTY TO COVER ANY SHOWER ACTIVITY THAT PERSISTS. ANOTHER CONCERN WITH THIS LINE OF CONVERGENCE ALONG THE COAST IS WATERSPOUT ACTIVITY. ALTHOUGH THE BOUNDARY IS NOT PROMINENT ON THE GULF COAST, CAN NOT RULE ONE OUT ACROSS ANY OF THE SOUTH FLORIDA WATERS THIS MORNING. COMPARING LAST NIGHTS SOUNDING AND THE WATER VAPOR IMAGERY, THE MOISTURE LOOKS TO BE FAIRLY SHALLOW. THE SOUNDING SHOWS A STRONG CAP IS IN PLACE AT AROUND 800MB. NAM MODEL SOUNDINGS SHOW IT SHOULD HOLD, EVEN WITH THE FRONT APPROACHING. THE WATER VAPOR IMAGERY IS SHOWING THAT THE MOISTURE IS REMAINING MAINLY OVER NORTH FLORIDA AND SOUTH GEORGIA, WITH LITTLE PROGRESSION TO THE SOUTH. SO, THIS WILL LEND CREDENCE TO THE LOW POPS THE MODELS ARE FORECASTING FOR TODAY, WITH A LOW END CHANCE OVER THE A PORTION OF THE CWA THIS AFTERNOON. THE FRONT WILL SLOWLY PROGRESS TO THE SOUTH, THROUGH THE CWA TODAY, AS THE MAIN LOW IS WELL AWAY FROM THE AREA, NORTHEAST OF MAINE, AND PULLING AWAY. MODELS SHOW THE FRONT WILL MAKE IT THROUGH MOST OF SOUTH FLORIDA AND PERHAPS TO THE KEYS BEFORE STALLING OUT. IT WILL THEN REMAIN THROUGH WEDNESDAY AS A WEAK BOUNDARY, KEEPING A SLIGHT CHANCE OF SHOWERS IN THE FORECAST FOR PORTIONS OF THE CWA UNTIL WEDNESDAY EVENING. EVEN THAT WILL BE MORE OR LESS ALONG THE ATLANTIC COAST AND OVER THE ATLANTIC WATERS. HIGH PRESSURE WILL BUILD IN OVER THE SOUTH EASTERN US, BUT NEVER DIG FAR ENOUGH SOUTH TO PUSH THE FRONT AWAY FROM THE AREA. MEANWHILE, ANOTHER LOW WILL MOVE OUT OF THE ROCKIES TODAY AND QUICKLY MOVE INTO THE PLAINS. MODELS INDICATE IT SHOULD BE OVER THE MISSISSIPPI VALLEY TONIGHT AND THEN APPEAR TO WASH OUT AS IT MOVES ACROSS THE APPALACHIANS. MODELS SHOW IT WILL REFORM OFF THE MID ATLANTIC COAST TUESDAY NIGHT AND BEGIN TO INTERACT WITH THE STALLED BOUNDARY. AS IT DOES, AS VERY STRONG HIGH WILL MOVE OUT OF WESTERN CANADA AND INTO THE PLAINS. THIS HIGH WILL WORK WITH THE LOW TO PUSH THE FRONT OUT OF THE AREA WEDNESDAY NIGHT AND WILL MOVE COOLER, DRIER AIR INTO SOUTH FLORIDA BY THURSDAY MORNING. HOWEVER, EVEN THOUGH IT WILL BE A SIGNIFICANT COOL DOWN, IT WILL NOT BE ENOUGH TO WARRANT ANY HEADLINES. LOWS THURSDAY LOOK TO BE IN THE MID 40S FOR THE INTERIOR LAKE REGION TO THE UPPER 50S ALONG THE ATLANTIC COAST. THE GULF COAST LOOKS TO BE IN THE UPPER 40S TO LOW 50S. HIGHS THURSDAY WILL RANGE FROM THE LOW 60S IN THE LAKE REGION TO AROUND 70 IN THE MIAMI AREA. THIS HIGH IS VERY TRANSIENT AND WILL BE GONE BY THE WEEKEND. THIS WILL ALLOW TEMPERATURES TO QUICKLY REBOUND AND COASTAL SHOWERS TO MAKE A RETURN POSSIBLY BY FRIDAY. THE FLOW WILL CONTINUE TO BE EASTERLY, SO THE ATLANTIC COAST LOOKS TO HAVE THE BEST CHANCE FOR SHOWER ACTIVITY. BY THE END OF THE WEEKEND, SOUTH FLORIDA WILL BE BACK UNDER THE WESTERN EDGE OF AN UPPER LEVEL RIDGE AND STILL IN EASTERLY SFC FLOW. MODELS ARE SHOWING A CHANCE FOR SHOWERS ACROSS THE AREA BY SUNDAY. AVIATION... ALTHOUGH THE RECENT COMPUTER MODEL GUIDANCE DOES NOT INDICATE MUCH IN THE WAY OF IFR VISIBILITY OR CEILING RESTRICTIONS OR MUCH POTENTIAL FOR WIDESPREAD FOG DEVELOPMENT THIS MORNING...CONDITIONS COULD BE FAVORABLE FOR LOW STRATUS AND/OR AREAS OF FOG AS A COLD FRONT CONTINUES TO MOVE INTO NORTHERN FLORIDA. ALL TAF SITES HAVE BEEN ASSIGNED PERIODS OF MVFR VISIBILITY RESTRICTIONS FROM 09Z TO 12Z THIS MORNING. BRIEF PERIODS OF NEAR IFR CONDITIONS MAY BE POSSIBLE AND WILL HAVE TO AMEND IF/WHEN CONDITIONS WARRANT. REGIONAL WINDS ARE EXPECTED TO BE LIGHT AND SOMEWHAT VARIABLE AT TIMES. MARINE... SHOWER ACTIVITY WILL BE POSSIBLE TODAY AS A COLD FRONT SLOWLY MOVES THROUGH THE AREA. WINDS WILL SLOWLY TURN TO THE NORTH AND NORTHEAST TODAY. THERE IS A SLIGHT CHANCE OF A WATERSPOUT, MAINLY ALONG A CONVERGENCE LINE ALONG THE ATLANTIC COAST THIS MORNING. THE FRONT WILL STALL JUST TO THE SOUTH, KEEP A SLIGHT CHANCE OF SHOWERS THROUGH WEDNESDAY. WEDNESDAY NIGHT, A STRONG HIGH WILL BUILD IN, BRINGING BREEZY CONDITIONS AND BUILDING SEAS FOR THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 80 70 80 67 / 30 20 20 20 FORT LAUDERDALE 81 72 80 69 / 20 20 20 10 MIAMI 82 71 82 69 / 20 20 10 10 NAPLES 80 65 81 64 / 10 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...13/SI LONG TERM....13/SI AVIATION...60/BD Area Forecast Discussion National Weather Service Spokane WA 424 AM PST MON JAN 5 2015 .SYNOPSIS... The north Idaho Panhandle and far northeast Washington will receive periods of snow through Monday afternoon. The valleys around Leavenworth and Lake Chelan will likely experience periods of freezing rain. Wintry precipitation will decrease Monday and Monday night as warmer air spreads over the Inland Northwest. High pressure will build over the region Tuesday night into Wednesday bringing dry conditions and areas of low clouds and fog through Thursday. The weather for Friday into next weekend looks mild and unsettled with the potential for light rain or snow. && .DISCUSSION... Update sent to remove winter weather advisories for the Columbia Basin, and extend the East Slopes and Okanogan Valley. Per latest surface observations, it is conceivable that freezing rain is falling in some of the valleys of the East Slopes, particularlynear Lake Wenatchee and upper reaches of the Methow Valley. Tough to gauge via cams given the time of day but rain is falling on Blewett and Stevens Passes while the valleys remain in the 20s. Light snow has returned to Oroville with roads becoming snow covered. Not the heavy snow we saw in Idaho Saturday but enough to complicate travel this morning. For the Columbia Basin and Wenatchee Area, temperatures remain cold and below freezing west of Ritzville to Davenport. However, strong westerly flow is producing quite the rain shadow and even when precip extends into Wenatchee from time to time...it is a brief trace so the threat for widespread winter impacts remains low. && .AVIATION... 12Z...A frontal boundary remains draped across northern WA/ID this morning with a rich feed of subtropical moisture streaming into the region. Spokane, C`DA, Pullman, and Lewiston have warmed above freezing and will mainly deal with gusty winds along with rain and MVFR cigs today. Cooler air remains trapped in the lee of the Cascades from Moses Lake to Wenatchee and has led to fog and stratus. Any precip hitting these terminals will be brief and light but could fall in the form of sleet or freezing rain through midday. Precip chances are not very high given the Cascade rain shadow. There is a higher threat for freezing rain in the East Slopes of the WA Cascades. /sb && .PREV DISCUSSION... /ISSUED / DISCUSSION... Monday through Tuesday: The winter storm will begin winding down today as warmer air moves into the region and snow levels rise. As of 2AM...the warm front has stalled from NW Washington to Missoula, MT. A rich fetch of subtropical moisture continues to be transported into the region along this boundary with periods of light to moderate precipitation ongoing across the Cascade Crest, Idaho Panhandle, and far northern WA. In between...spotty light precipitation is reaching into the Basin at times. South of the warm front, the threat for winter weather has ended for much of southeastern WA and the lower ID Panhandle where snow levels have risen between 3000-5000 feet. All winter highlights will be taken down and rain will be the dominate precipitation type through Monday. North of the warm front, temperatures remain in the 20s for locations like Sandpoint, Bonners Ferry, Colville, and Republic. Precipitation redeveloping at this hour will remain in the form of snow with an additional 1-3 inches possible through morning. Snow will also continue in the Central Panhandle mountains mainly above 3000 feet but snow levels will also be rising near or above 5K ft by this afternoon. Models suggest the strongest isentropic ascent in combination with orographics will be from the WA Palouse...east into the Central Panhandle Mtns which could see on the order of another 0.50 - 1.00" of liquid through this afternoon. This may cause problems for smaller streams and creeks and we will be closely monitoring Paradise Creek. Winds are also cranking in the foothills of the Blue Mtns which have pushed temperatures at 2AM into the 40s to lower 50s. Look for the strongest winds this morning then decreasing in the afternoon and a wind advisory has been issued to address these local concerns. Further west, things get a bit more tricky. Cooler air remains trapped in the lee of the Cascades with below freezing temperatures from Ritzville to the East Slopes...northward into the Okanogan Valley. Strong westerly flow is only allowing spotty precipitation extend pass the Cascade Crest but precip type is a mix of sleet, snow, and freezing rain. HRRR suggest another band of light precip developing this morning as the last rich slug of moisture crosses the Cascades so will hold off until we see if this materializes before cancelling any highlights. A bigger concern will be in the valleys tucked closer to the Cascade Crest which will be more susceptible to light or brief moderate precip and potential for light ice accumulations. The warmer air has arrived aloft with above freezing temperatures observed to 4000 feet across southern Chelan County and locations like Lake Wenatchee still in the 20s...ice accumulations are a strong possibility! Precipitation trends will migrate northward tonight into Tuesday and depart the region Tuesday evening. High pressure will build inland and deliver dry but soggy conditions at the surface with widespread fog and low clouds. /sb Wednesday through Saturday: A dry ridge will keep things quiet on Wednesday and into Thursday. The ridge over the region will shift to the East and begin to flatten Thursday into Friday. The models a series of frontal waves will move through the ridge. The first passing through the region on Friday afternoon. The trends with the models have been slowly drying out the amount moisture associated with this front. The precip chances have been decreased and will mainly impact the Cascades and mountains in the Idaho Panhandle with Columbia Basin having low chance of receiving a small amount of snow. A small dry ridge will fill in behind the front on Saturday decreasing precip chances for the rest of the period. Temperatures will range low to mid 30s for the highs and mid to upper 20s for the lows. Sunday and Monday: The model agreement for this period is very poor. The forecast leans toward the worse case scenario with bringing in the next system and delivering another round of precip to the region. Temperatures will range from the low to mid 30s for the highs and mid to upper 20s for the lows. /JDC && .PRELIMINARY POINT TEMPS/POPS... Spokane 39 33 35 27 36 28 / 100 30 10 0 0 0 Coeur d`Alene 40 33 38 28 37 28 / 100 60 20 10 0 0 Pullman 45 36 43 31 42 33 / 100 20 10 0 0 0 Lewiston 48 38 47 34 47 35 / 80 10 10 0 0 0 Colville 35 32 33 27 32 26 / 80 50 30 10 0 0 Sandpoint 34 32 35 24 29 26 / 100 90 60 10 0 0 Kellogg 35 34 38 28 36 31 / 100 100 50 10 0 0 Moses Lake 42 32 37 31 39 30 / 30 10 10 0 0 0 Wenatchee 42 33 36 33 37 32 / 30 10 10 0 0 0 Omak 34 30 35 30 35 28 / 50 10 10 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Winter Storm Warning until 4 AM PST Tuesday for Central Panhandle Mountains. Winter Storm Warning until 4 PM PST this afternoon for Northern Panhandle. WA...Winter Storm Warning until 4 PM PST this afternoon for Northeast Mountains-Okanogan Highlands. Winter Storm Warning until Noon PST today for East Slopes Northern Cascades-Okanogan Valley. Wind Advisory until 3 PM PST this afternoon for Lower Garfield and Asotin Counties. && $$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
124 PM MST MON JAN 5 2015 .UPDATE... ISSUED AT 123 PM MST MON JAN 5 2015 THE PULSY NATURE OF CHINOOK WINDS CONTINUES TO PLAY GAMES WITH TODAY/S FORECAST. FOR INSTANCE MANY AREAS IN THE FRONT RANGE FOOTHILLS HAVE BEEN GUSTING FROM THE WEST-NORTHWEST AT 30-45KTS WITH HIGHER GUSTS TO AROUND 75KTS AT TIMES. WHILE OTHER AREAS ONLY 5-15KTS FROM THE SOUTH-SOUTHWEST. A SIMILAR SITUATION IS OCCURRING ON THE NEARBY PLAINS. CASE IN POINT...WESTERLY WINDS AT DIA HAVE BOUNDED BACK AND FROM 10 TO 24 MPH PAST COUPLE OF HOURS WITH A PEAK GUST TO 38 MPH JUST THIS PAST HOUR. ONCE WINDS KICKED IN ALONG THE FOOTHILLS TEMPERATURES SOARED AS MUCH AS 30 DEGS F. WHERE WINDS WERE BLOWING ON THE PLAINS CURRENT TEMPS IN THE UPPER 40S TO MID 50S. WHEREAS FARTHER OUT ON THE PLAINS WHERE WINDS ARE LIGHT AND VARIABLE...READINGS ARE STRUGGLING TO CLIMB OUT OF THE TEENS. HOWEVER IN THE NEXT COUPLE OF HOURS...MESOSCALE MODELS SHOW GUSTY NWLY WINDS BLOWING DOWN OFF THE CHEYENNE RIDGE. SHOULD THIS OCCUR...PRESUMABLY WE SEE QUICK MIXING OF THE BNDRY LAYER RESULTING IS A SPIKE IN TEMPS...MAINLY UP ALONG THE WYOMING AND NEBRASKA BORDERS. UPDATED TEMPERATURE AND WINDS GRIDS TO BETTER REFLECT THE GUSTY NATURE OF THE WINDS AND THE BITTER COLD AIR TRAPPED ALONG THE SOUTH PLATTE RIVER. ALSO BEEFED UP POPS AND SNOW AMOUNTS IN THE NRN MTNS FOR THE REST OF TODAY WHERE ANOTHER 2-4 INCHES OF SNOW POSSIBLE RIDGETOPS AND NW FACING SLOPES BY THIS EVENING. UPDATE ISSUED AT 943 AM MST MON JAN 5 2015 WINDS WILL CONTINUE TO HOWL IN THE HIGH COUNTRY AND ACROSS NORTHERN PORTIONS OF SOUTH PARK FOR THE REMAINDER OF TODAY. SEVERAL FRONT RANGE WIND SENSORS HAVE ALREADY MEASURED GUSTS IN THE 70 TO 80 MPH RANGE. THE STRONGEST WIND GUST MEASURED THUS FAR WAS 85 MPH AT THE GOLD HILL SITE JUST WEST OF BOULDER. THE 109 MPH WIND GUST RECORDED DURING THE PAST SEVERAL HOURS AT THE KENOSHA PASS WIND SENSOR IS IN ERROR. FOR SOME REASON THIS SENSOR LOCKS ON 109 MPH WHENEVER THERE`S STRONG WINDS...BLOWING SNOW AND/OR VERY COLD TEMPERATURES AT THAT SITE. THESE POTENTIALLY DAMAGING AND VERY GUSTY WEST WINDS ARE EXPECTED TO BECOME MORE WIDESPREAD IN THE FRONT RANGE MOUNTAINS AND FOOTHILLS BY LATE THIS MORNING WITH PEAK GUSTS TO AROUND 85 MPH EXPECTED THROUGH LATE THIS AFTERNOON. THE STRONG WINDS ARE LIKELY TO PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW IN OPEN AREAS. WINDS ARE EXPECTED TO DECREASE IN SPEED BY MID TO LATE THIS EVENING. THAT SAID...WEST WINDS OF 25-40 AND GUSTS TO AROUND 60 MPH ACROSS NORTHERN PORTIONS OF SOUTH PARK HAS PROMPTED A BLOWING SNOW ADVISORY FOR ZONE 37. ADVISORY GOES UNTIL 5 PM MST TODAY. CDOT CAMS CLEARLY INDICATE QUITE A BIT OF BLOWING SNOW ALONG U.S. HIGHWAY 285 NORTH OF FAIRPLAY. ELSEWHERE...STRONG WESTERLY WINDS ARE JUST OFF THE SFC BASED ON KFTG WIND PROFILER...ACARS WIND PLOTS AND LATEST RAP WIND DATA. ANOTHER INDICATION OF THESE STRONG WINDS CAN BE SURMISED BY THE RAPID RISE IN TEMPERATURE AT DIA IN THE PAST HOUR WHERE IT ROSE FROM 17F TO 41F. SUSPECT ITS ONLY A MATTER OF TIME BEFORE GUSTY WARM CHINOOK WINDS WILL MIX DOWN ACROSS PORTIONS OF THE I-25 URBAN CORRIDOR AND WRN PORTIONS OF THE PALMER DIVIDE. ITS ALREADY IN THE LOW/MID 40S ON THE PALMER DVD IN DOUGLAS COUNTY. && .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 345 AM MST MON JAN 5 2015 MAIN CONCERN TODAY AND THIS EVENING IS THE HIGH WIND POTENTIAL IN THE MOUNTAINS AND FOOTHILLS. CURRENT OBSERVATIONS SHOWING WINDS BEGINNING TO INCREASE BUT STILL ONLY IN THE 30-45 MPH RANGE. 88D ALSO SHOWING WIND SIGNATURE INCREASING IN THE PAST HOUR AS WINDS BEGIN TO DESCEND THROUGH THE FOOTHILLS OF BOULDER COUNTY. SURFACE PRESSURE ALSO BEGINNING TO FALL BUT BEST PRESSURE FALLS STILL OVER MONTANA AND WYOMING. SURFACE PRESSURE GRADIENT WILL CONTINUE TO STEEPEN ACROSS THE STATE AS THE ADDITIONAL FALLS WORK INTO EASTERN COLORADO. LATEST MODELS SHOWING SURFACE GRADIENT TO TIGHTEN TO AROUND 15 MB FROM GJT TO DEN BY LATER THIS AM AND THROUGH THE AFTERNOON. CROSS SECTIONS SHOWING 60-70KT CROSS BARRIER FLOW DEVELOPING THIS MORNING BEFORE DECREASING THIS EVENING. STRONG MID LEVEL WARMING WILL RESULT IN STRONG INVERSIONS DEVELOPING AT MOUNTAIN TOP LEVEL ALONG WITH ADEQUATE WIND SHEAR PROFILE FOR AMPLIFIED MOUNTAIN WAVE. THE ONE FACTOR AGAINST HIGH WINDS TODAY IS THE INCREASED MOISTURE AND LIGHT SNOW EXPECTED OVER HIGHER NORTHERN MOUNTAINS. LATEST RAP/HRRR SHOWING PEAK WIND GUSTS IN THE 60-80KT RANGE FROM 16Z-23Z. FEEL THERE ENOUGH CONFIDENCE TO UPGRADE THE WATCH TO A WARNING FOR THE MOUNTAINS AND FOOTHILLS. WINDS MAY HAVE A HARD TIME DEVELOPING ACROSS LOWER ELEVATIONS OF THE FOOTHILLS BUT BELIEVE THE STRONG GRADIENT WILL AID IN THE WIND DEVELOPMENT. EXPECT LIGHT SNOW TO DEVELOP OVER FAR NORTHERN MOUNTAINS TODAY BUT EXPECT SNOWFALL AMOUNTS WILL BE ON THE LIGHT SIDE DUE TO LOW LAPSE RATES DESPITE THE STRONG OROGRAPHIC FLOW. BEST SNOWFALL LIKELY WILL BE OVER ZONE 31 WITH UP TO 3 INCHES POSSIBLE TODAY. TEMPERATURES WILL BE WARMER TODAY ACROSS LOWER ELEVATIONS...ESPECIALLY IN WINDY AREAS AT THE BASE OF THE FOOTHILLS AND PALMER DIVIDE. FURTHER NORTH AND EAST OF DENVER...COLD AIR MAY BE A BIT HARDER TO SCOUR OUT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 204 AM MST MON JAN 5 2015 NW FLOW ALOFT WILL REMAIN OVER THE AREA FM TUE INTO WED. SOME MOISTURE WILL CONTINUE TO AFFECT THE NRN MTNS ON TUE HOWEVER LAPSE RATES REMAIN STABLE SO ANY SNOW WILL BE VERY LIGHT. OVER NERN CO IT WILL BE DRY ON TUE WITH A WEAK SFC LEE TROUGH ALONG THE FRONT RANGE. ONCE AGAIN TEMP FCST WILL BE DEPENDENT ON LINGERING SNOW COVER. GUIDANCE TEMPS WRM READINGS INTO THE LOWER TO MID 50S OVER DENVER WITH 40S ACROSS THE PLAINS. HOWEVER 850-700 MB TEMPS WILL COOL AROUND 3 DEGREES C AND WITH LESS DOWNSLOPE COMPONENT NOT SURE READINGS ARE GOING TO BE AS WRM AS MONDAY SO WILL KEEP HIGHS IN THE 40S ALONG THE FRONT RANGE WITH 30S OVER THE FAR NERN PLAINS. TUE NIGHT INTO WED ANOTHER SHOT OF COLD AIR WILL MOVE INTO NERN CO WITH SHALLOW UPSLOPE THRU EARLY WED MORNING. LATEST CROSS-SECTIONS SHOW ENOUGH MOISTURE FOR AT LEAST A SLIGHT CHC OF LIGHT SNOW OVER NERN CO. IN THE MTNS WILL NOT MENTION ANY PCPN. AS FOR HIGHS BELIEVE ECMWF HAS A BETTER HANDLE WITH COLD AIRMASS SO WILL KEEP HIGHS IN THE TEENS OVER THE PLAINS WITH 25 TO 30 CLOSER TO THE FOOTHILLS. ON THU DRY WNW FLOW ALOFT WILL BE OVER THE AREA AS A SFC LEE TROUGH REDEVELOPS OVER ERN CO. THIS SHOULD LEAD TO WARMER TEMPS WITH READINGS RISING BACK INTO THE 45 TO 50 DEGREE RANGE AROUND DENVER WITH UPPER 30S TO LOWER 40S OVER THE FAR NERN PLAINS. BY THU NIGHT INTO A FRI ANOTHER SHOT OF COOLER AIR WILL MOVE INTO NERN CO. THUS WILL DROP HIGHS BACK INTO THE 20S OVER THE PLAINS WITH LOWER TO MID 30S AROUND DENVER. BOTH THE ECMWF AND GFS SHOW SOME MOISTURE IN THE LOWER LEVELS WITH SHALLOW UPSLOPE COMPONENT LATE THU NIGHT INTO FRI MORNING SO IT WOULDN`T BE A TOTAL SURPRISE TO SEE AT LEAST A SLIGHT CHC OF LIGHT SNOW OVER NERN CO. IN THE MTNS THERE IS SOME INCREASE IN MOISTURE BY AFTN SO WILL MENTION A SLIGHT CHC OF SNOW AS WELL. BY SAT THE ECMWF AND GFS CONTINUE TO DIFFER ON THE OVERALL PTRN. THE ECMWF HAS DRY NWLY FLOW ALOFT OVER THE AREA WITH DOWNSLOPE WARMING OCCURRING OVER NERN CO WHILE THE GFS SHOWS A WK DISTURBANCE MOVING ACROSS WITH QUITE A BIT OF MOISTURE. IN ADDITION THE GFS KEEPS A SHALLOW COLD AIRMASS OVER NERN CO AS WELL. FOR NOW WILL KEEP A SLIGHT CHC OF PCPN IN THE FCST AND TREND WITH THE COOLER GFS. ON SUN THE GFS SHOWS ANOTHER WK DISTURBANCE MOVING ACROSS WITH ANOTHER SHOT OF MOISTURE ESPECIALLY FOR THE MTNS WHILE KEEPING A SHALLOW LYR OF COLD AIR OVER NERN CO. MEANWHILE THE ECMWF KEEPS MAINLY DRY NWLY FLOW ALOFT OVER THE AREA HOWEVER IT DOES SHOW A SHOT OF COOLER AIR MOVING INTO NERN CO DURING THE DAY. && .AVIATION...(FOR THE TAFS THROUGH 00Z TUESDAY LATE AFTERNOON) ISSUED AT 123 PM MST MON JAN 5 2015 THE GUSTY AND ERRATIC NATURE OF CHINOOK WINDS CREATING A FCST CHALLENGE AT AIRPORT TERMINALS THIS AFTERNOON. SPEEDS AND DIRECTIONS ALL OVER THE PLAINS. AT THIS HOUR WLY WINDS AT KDEN GUSTING TO 30KTS AND AT KBJC NEAR THE FOOTHILLS 58KTS! WHILE AT KAPA WINDS ARE VARIABLE AT 4 KTS. THAT/S CHINOOK WINDS FOR YOU. WILL LIKELY CONTINUE TO CHASE WINDS FOR THE REMAINDER OF THE AFTERNOON. OTHERWISE NO PRECIP AND VFR CONDITIONS NEXT 24 HOURS. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ037. HIGH WIND WARNING UNTIL 11 PM MST THIS EVENING FOR COZ033>036. && $$ UPDATE...BAKER SHORT TERM...ENTREKIN LONG TERM...RPK AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
943 AM MST MON JAN 5 2015 .UPDATE... ISSUED AT 943 AM MST MON JAN 5 2015 WINDS WILL CONTINUE TO HOWL IN THE HIGH COUNTRY AND ACROSS NORTHERN PORTIONS OF SOUTH PARK FOR THE REMAINDER OF TODAY. SEVERAL FRONT RANGE WIND SENSORS HAVE ALREADY MEASURED GUSTS IN THE 70 TO 80 MPH RANGE. THE STRONGEST WIND GUST MEASURED THUS FAR WAS 85 MPH AT THE GOLD HILL SITE JUST WEST OF BOULDER. THE 109 MPH WIND GUST RECORDED DURING THE PAST SEVERAL HOURS AT THE KENOSHA PASS WIND SENSOR IS IN ERROR. FOR SOME REASON THIS SENSOR LOCKS ON 109 MPH WHENEVER THERE`S STRONG WINDS...BLOWING SNOW AND/OR VERY COLD TEMPERATURES AT THAT SITE. THESE POTENTIALLY DAMAGING AND VERY GUSTY WEST WINDS ARE EXPECTED TO BECOME MORE WIDESPREAD IN THE FRONT RANGE MOUNTAINS AND FOOTHILLS BY LATE THIS MORNING WITH PEAK GUSTS TO AROUND 85 MPH EXPECTED THROUGH LATE THIS AFTERNOON. THE STRONG WINDS ARE LIKELY TO PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW IN OPEN AREAS. WINDS ARE EXPECTED TO DECREASE IN SPEED BY MID TO LATE THIS EVENING. THAT SAID...WEST WINDS OF 25-40 AND GUSTS TO AROUND 60 MPH ACROSS NORTHERN PORTIONS OF SOUTH PARK HAS PROMPTED A BLOWING SNOW ADVISORY FOR ZONE 37. ADVISORY GOES UNTIL 5 PM MST TODAY. CDOT CAMS CLEARLY INDICATE QUITE A BIT OF BLOWING SNOW ALONG U.S. HIGHWAY 285 NORTH OF FAIRPLAY. ELSEWHERE...STRONG WESTERLY WINDS ARE JUST OFF THE SFC BASED ON KFTG WIND PROFILER...ACARS WIND PLOTS AND LATEST RAP WIND DATA. ANOTHER INDICATION OF THESE STRONG WINDS CAN BE SURMISED BY THE RAPID RISE IN TEMPERATURE AT DIA IN THE PAST HOUR WHERE IT ROSE FROM 17F TO 41F. SUSPECT ITS ONLY A MATTER OF TIME BEFORE GUSTY WARM CHINOOK WINDS WILL MIX DOWN ACROSS PORTIONS OF THE I-25 URBAN CORRIDOR AND WRN PORTIONS OF THE PALMER DIVIDE. ITS ALREADY IN THE LOW/MID 40S ON THE PALMER DVD IN DOUGLAS COUNTY. && .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 345 AM MST MON JAN 5 2015 MAIN CONCERN TODAY AND THIS EVENING IS THE HIGH WIND POTENTIAL IN THE MOUNTAINS AND FOOTHILLS. CURRENT OBSERVATIONS SHOWING WINDS BEGINNING TO INCREASE BUT STILL ONLY IN THE 30-45 MPH RANGE. 88D ALSO SHOWING WIND SIGNATURE INCREASING IN THE PAST HOUR AS WINDS BEGIN TO DESCEND THROUGH THE FOOTHILLS OF BOULDER COUNTY. SURFACE PRESSURE ALSO BEGINNING TO FALL BUT BEST PRESSURE FALLS STILL OVER MONTANA AND WYOMING. SURFACE PRESSURE GRADIENT WILL CONTINUE TO STEEPEN ACROSS THE STATE AS THE ADDITIONAL FALLS WORK INTO EASTERN COLORADO. LATEST MODELS SHOWING SURFACE GRADIENT TO TIGHTEN TO AROUND 15 MB FROM GJT TO DEN BY LATER THIS AM AND THROUGH THE AFTERNOON. CROSS SECTIONS SHOWING 60-70KT CROSS BARRIER FLOW DEVELOPING THIS MORNING BEFORE DECREASING THIS EVENING. STRONG MID LEVEL WARMING WILL RESULT IN STRONG INVERSIONS DEVELOPING AT MOUNTAIN TOP LEVEL ALONG WITH ADEQUATE WIND SHEAR PROFILE FOR AMPLIFIED MOUNTAIN WAVE. THE ONE FACTOR AGAINST HIGH WINDS TODAY IS THE INCREASED MOISTURE AND LIGHT SNOW EXPECTED OVER HIGHER NORTHERN MOUNTAINS. LATEST RAP/HRRR SHOWING PEAK WIND GUSTS IN THE 60-80KT RANGE FROM 16Z-23Z. FEEL THERE ENOUGH CONFIDENCE TO UPGRADE THE WATCH TO A WARNING FOR THE MOUNTAINS AND FOOTHILLS. WINDS MAY HAVE A HARD TIME DEVELOPING ACROSS LOWER ELEVATIONS OF THE FOOTHILLS BUT BELIEVE THE STRONG GRADIENT WILL AID IN THE WIND DEVELOPMENT. EXPECT LIGHT SNOW TO DEVELOP OVER FAR NORTHERN MOUNTAINS TODAY BUT EXPECT SNOWFALL AMOUNTS WILL BE ON THE LIGHT SIDE DUE TO LOW LAPSE RATES DESPITE THE STRONG OROGRAPHIC FLOW. BEST SNOWFALL LIKELY WILL BE OVER ZONE 31 WITH UP TO 3 INCHES POSSIBLE TODAY. TEMPERATURES WILL BE WARMER TODAY ACROSS LOWER ELEVATIONS...ESPECIALLY IN WINDY AREAS AT THE BASE OF THE FOOTHILLS AND PALMER DIVIDE. FURTHER NORTH AND EAST OF DENVER...COLD AIR MAY BE A BIT HARDER TO SCOUR OUT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 204 AM MST MON JAN 5 2015 NW FLOW ALOFT WILL REMAIN OVER THE AREA FM TUE INTO WED. SOME MOISTURE WILL CONTINUE TO AFFECT THE NRN MTNS ON TUE HOWEVER LAPSE RATES REMAIN STABLE SO ANY SNOW WILL BE VERY LIGHT. OVER NERN CO IT WILL BE DRY ON TUE WITH A WEAK SFC LEE TROUGH ALONG THE FRONT RANGE. ONCE AGAIN TEMP FCST WILL BE DEPENDENT ON LINGERING SNOW COVER. GUIDANCE TEMPS WRM READINGS INTO THE LOWER TO MID 50S OVER DENVER WITH 40S ACROSS THE PLAINS. HOWEVER 850-700 MB TEMPS WILL COOL AROUND 3 DEGREES C AND WITH LESS DOWNSLOPE COMPONENT NOT SURE READINGS ARE GOING TO BE AS WRM AS MONDAY SO WILL KEEP HIGHS IN THE 40S ALONG THE FRONT RANGE WITH 30S OVER THE FAR NERN PLAINS. TUE NIGHT INTO WED ANOTHER SHOT OF COLD AIR WILL MOVE INTO NERN CO WITH SHALLOW UPSLOPE THRU EARLY WED MORNING. LATEST CROSS-SECTIONS SHOW ENOUGH MOISTURE FOR AT LEAST A SLIGHT CHC OF LIGHT SNOW OVER NERN CO. IN THE MTNS WILL NOT MENTION ANY PCPN. AS FOR HIGHS BELIEVE ECMWF HAS A BETTER HANDLE WITH COLD AIRMASS SO WILL KEEP HIGHS IN THE TEENS OVER THE PLAINS WITH 25 TO 30 CLOSER TO THE FOOTHILLS. ON THU DRY WNW FLOW ALOFT WILL BE OVER THE AREA AS A SFC LEE TROUGH REDEVELOPS OVER ERN CO. THIS SHOULD LEAD TO WARMER TEMPS WITH READINGS RISING BACK INTO THE 45 TO 50 DEGREE RANGE AROUND DENVER WITH UPPER 30S TO LOWER 40S OVER THE FAR NERN PLAINS. BY THU NIGHT INTO A FRI ANOTHER SHOT OF COOLER AIR WILL MOVE INTO NERN CO. THUS WILL DROP HIGHS BACK INTO THE 20S OVER THE PLAINS WITH LOWER TO MID 30S AROUND DENVER. BOTH THE ECMWF AND GFS SHOW SOME MOISTURE IN THE LOWER LEVELS WITH SHALLOW UPSLOPE COMPONENT LATE THU NIGHT INTO FRI MORNING SO IT WOULDN`T BE A TOTAL SURPRISE TO SEE AT LEAST A SLIGHT CHC OF LIGHT SNOW OVER NERN CO. IN THE MTNS THERE IS SOME INCREASE IN MOISTURE BY AFTN SO WILL MENTION A SLIGHT CHC OF SNOW AS WELL. BY SAT THE ECMWF AND GFS CONTINUE TO DIFFER ON THE OVERALL PTRN. THE ECMWF HAS DRY NWLY FLOW ALOFT OVER THE AREA WITH DOWNSLOPE WARMING OCCURRING OVER NERN CO WHILE THE GFS SHOWS A WK DISTURBANCE MOVING ACROSS WITH QUITE A BIT OF MOISTURE. IN ADDITION THE GFS KEEPS A SHALLOW COLD AIRMASS OVER NERN CO AS WELL. FOR NOW WILL KEEP A SLIGHT CHC OF PCPN IN THE FCST AND TREND WITH THE COOLER GFS. ON SUN THE GFS SHOWS ANOTHER WK DISTURBANCE MOVING ACROSS WITH ANOTHER SHOT OF MOISTURE ESPECIALLY FOR THE MTNS WHILE KEEPING A SHALLOW LYR OF COLD AIR OVER NERN CO. MEANWHILE THE ECMWF KEEPS MAINLY DRY NWLY FLOW ALOFT OVER THE AREA HOWEVER IT DOES SHOW A SHOT OF COOLER AIR MOVING INTO NERN CO DURING THE DAY. && .AVIATION...(FOR THE TAFS THROUGH 18Z TUESDAY MORNING) ISSUED AT 943 AM MST MON JAN 5 2015 SOUTH-SOUTHWEST WINDS OF 6-12KTS AT KDEN AND KAPA ARE EXPECTED TO TURN WESTERLY 15-25KTS IN THE NEXT HOUR...AND AFTER THAT POSSIBLY GUST TO AROUND 35KTS. STRONGER WEST WINDS ARE LIKELY CLOSER TO THE FTHLS SUCH AS AT KBJC WHERE GUSTS TO AROUND 45 KTS WILL BE POSSIBLE DURING THE LATE MORNING AND AFTERNOON HOURS. BLOWING SNOW MAY BRIEFLY REDUCE VISIBILITIES AT THESE LOCATIONS ESPECIALLY AT KBJC. WINDS ARE EXPECTED TO SUBSIDE AT KDEN AND KAPA EARLY THIS EVENING AND TURN DRAINAGE...AND BY MID TO LATE EVENING AT KBJC. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ037. HIGH WIND WARNING UNTIL 11 PM MST THIS EVENING FOR COZ033>036. && $$ UPDATE...BAKER SHORT TERM...ENTREKIN LONG TERM...RPK AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
127 PM EST MON JAN 5 2015 .SYNOPSIS... INTENSIFYING LOW PRESSURE HEADING INTO THE MARITIMES TODAY WILL YIELD BLUSTERY AND MUCH COLDER WEATHER FOR SOUTHERN NEW ENGLAND ALONG WITH THE RISK OF A FEW SNOW SHOWERS/SQUALLS POSSIBLE. WEAK LOW PRESSURE MAY BRING A PERIOD OF LIGHT SNOW DURING TUESDAY. AN ARCTIC FRONT CROSSES THE REGION WEDNESDAY...WHICH MAY PRODUCE A FEW SNOW SHOWERS OR SQUALLS. BLUSTERY AND BITTERLY COLD CONDITIONS ARE EXPECTED WEDNESDAY NIGHT INTO THURSDAY. MORE SNOW SHOWERS ARE POSSIBLE THURSDAY NIGHT AND FRIDAY...THEN MAINLY DRY CONDITIONS INTO NEXT WEEKEND WITH BELOW NORMAL TEMPERATURES. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 115 PM UPDATE... WIND GUSTS OF 30 TO IN SOME LOCALES 40+ KNOTS HAVE OCCURRED IN SOUTHERN NEW ENGLAND TODAY...WITH THE HIGHEST GUSTS OVER PORTIONS OF EASTERN MA INCLUDING BOSTON...AS WELL AS THE WORCESTER HILLS. ALSO THERE HAVE BEEN REPORTS OF TREES DOWN /SEE LATEST LSRBOX/. WIND GUSTS AT CT VALLEY AREA METAR SITES HAVE BEEN SOMEWHAT LOWER THAN TO THE EAST...BUT NAM AND HRRR BUFKIT FORECAST SOUNDINGS SHOWING POTENTIAL FOR 40 KTS TO MIX TO THE GROUND. CONTINUING THE WIND ADVISORY FOR THE COUNTY WARNING AREA. CONTINUE TO SEE CLOUD BANDS CROSSING NEW YORK STATE AND EXTENDING INTO OUR AREA...WITH ISOLATED SNOW SHOWERS ON RADAR. WILL CONTINUE TO MENTION POTENTIAL FOR ISOLATED/WIDELY SCATTERED SNOW SHOWERS. THERE IS STILL A POSSIBILITY FOR AN ISOLATED SNOW SQUALL THIS AFTERNOON. TEMPS/DEWPTS CONTINUE TO FALL AS COLDER AIR POURS IN. MINOR ADJUSTMENTS TO TEMPS/SKY COVER THIS AFTERNOON...OTHERWISE FORECAST LOOKS ON TRACK. PREVIOUS DISCUSSION... WINDS... POST FRONTAL AIRMASS STREAMING ACROSS THE REGION EARLY THIS MORNING WITH WITH WEST WINDS GUSTING ALREADY UP TO 40 MPH. AS COLD AIR ADVECTION INCREASES ALONG WITH THE PRES GRADIENT AND DEEPENING BLYR WILL RESULT IN WIND GUSTS VERY CLOSE TO WIND ADVISORY CRITERIA /SUSTAINED 31 MPH AND GREATER AND-OR G46MPH AND HIGHER/. DOWNSLOPE WIND COMPONENT /WNW WINDS/ WILL PROVIDE SOME ENHANCEMENT AS WELL. THUS WIND ADVISORY FOR ALL AREAS TODAY. SNOW SQUALL POTENTIAL... OTHER CONCERN FOR TODAY IS POTENTIAL FOR LAKE EFFECT SNOW SHOWERS/SQUALLS FROM NY STATE TO TRAVERSE INTO MA/RI AND CT. ALL MODEL GUIDANCE ESPECIALLY THE HI RES MODELS SHOW LONG FETCH ACROSS LAKE ONTARIO WITH STREAMLINES INDICATING A NARROW BAND OF CONVERGENCE INTO SOUTHERN NEW ENGLAND TODAY. FAIRLY STEEP LOW LEVEL LAPSE RATES TO ENHANCE POTENTIAL BAND DEVELOPMENT AND DURATION. THE 00Z BTV 4KM WRF IS CURRENT SIMULATING THE LAKE EFFECT BANDS VERY WELL ACROSS NY STATE EARLY THIS MORNING. THIS MODEL TRAVERSE THESE STREAMERS ACROSS THE NH/MA BORDER LATER THIS MORNING AND THEN INTO MA EARLY THIS AFTERNOON AND POSSIBLY PROPAGATING INTO CT/RI AND SOUTHEAST MA LATE THIS AFTERNOON TOWARD SUNSET. THESE MESOSCALE BANDS ARE ALWAYS DIFFICULT TO FORECAST ESPECIALLY SO FAR DOWNSTREAM FROM THE LAKES. THUS WE HAVE ABOVE AVERAGE FORECAST CONFIDENCE THAT ONE OR MORE OF THESE BANDS WILL SURVIVE SOMEWHERE INTO MA/CT AND-OR RI BUT LOW CONFIDENCE ON AREAL COVERAGE/INTENSITY AND DURATION. WHILE THESE SNOW BANDS TYPICALLY DON`T DELIVER HEAVY SNOW AMOUNTS...ANY SNOW BAND TODAY WILL HAVE THE POTENTIAL TO DUMP A QUICK HALF INCH OF SNOW IN A VERY SHORT PERIOD OF TIME ALONG WITH REDUCED VSBY AND BRIEF SLICK CONDITIONS. WILL ISSUE A SPECIAL WEATHER STATEMENT TO INCREASE PUBLIC AWARENESS REGARDING THE UNCERTAINTY BUT ALSO THE POTENTIAL BRIEF BUT HIGH IMPACT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... TONIGHT... ANY EARLY EVENING SNOW SHOWER ACTIVITY WILL WEAKEN/ERODE OR MOVE OFF THE SOUTH COAST SHORTLY AFTER SUNSET. COLD NIGHT AHEAD IN THE WAKE OF THE SHORT WAVE PASSAGE FROM TODAY. HIGH PRES OVER OH VLY WILL CREST OVER NEW ENGLAND. THIS WILL SET THE STAGE FOR IDEAL RADIATIONAL COOLING CONDITIONS WITH ALL LOCATIONS FALLING INTO THE TEENS WITH SINGLE DIGITS WELL INLAND. TUESDAY... CLIPPER-TYPE LOW RACES ACROSS THE REGION AND WILL BE ACCOMPANIED BY A PERIOD OF LIGHT SNOW REGIONWIDE. FAIRLY LOW AMPLITUDE SHORT WAVE ALONG WITH MOISTURE LACKING AND SYSTEM IS VERY PROGRESSIVE. THUS ALL MODEL GUID ONLY OFFERS A FEW HUNDREDS OF QPF. THEREFORE AS OF NOW JUST EXPECTING A COATING TO PERHAPS AN INCH OF SNOW. HOWEVER WILL HAVE TO WATCH LATER MODEL RUNS AND SEE IF AMPLITUDE AND MOISTURE SIMULATIONS CHANGE. IT WILL BE A COLD DAY GIVEN THE CHILLY START FOLLOWED BY CLOUDS RAPIDLY INCREASING ALONG WITH LIGHT SNOW/FLURRIES BY AFTERNOON. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * LEFTOVER LIGHT SNOW WILL PUSH OFFSHORE TUE NIGHT BUT MAY LINGER ACROSS CAPE COD AND THE ISLANDS * SCT SNOW SHOWERS AND A FEW SQUALLS POSSIBLE WED AS ARCTIC FRONT PASSES * DANGEROUSLY LOW WIND CHILL READINGS WED NIGHT INTO THU MORNING * MODERATION IN TEMPS INTO THE WEEKEND BUT REMAINING BELOW NORMAL OVERVIEW... HEMISPHERIC TELECONNECTION INDICES CONTINUE TO SHOW GENERALLY PROGRESSIVE PATTERN ACROSS THE LOWER 48 THROUGH THIS TIMEFRAME. HOWEVER...-EPO PATTERN LOOKS TO CONTINUE A STRONG E PACIFIC RIDGE WITH DEEP TROUGH ACROSS THE EASTERN U.S. AND CANADA THROUGH MID WEEK...THEN WILL SLOWLY PROGRESS E. WITH WEAK SHORT WAVES IN THE UPPER W-NW FLOW THAT BECOMES MORE NW BY LATE THIS WEEK...EXPECT TO SEE PERIODS OF SNOW SHOWERS MOVE ACROSS THE REGION BRINGING PROGRESSIVELY FRIGID AIR. THERE MAY BE A FEW SNOW SQUALLS DURING WED AS AN ARCTIC FRONT PASSES...BRINGING THE MOST BRUTALLY COLD CONDITIONS OF THE SEASON. WILL SEE TEMPS PLUMMET ALONG WITH STRONG NW WINDS CAUSING DANGEROUSLY LOW WIND CHILL READINGS. VERY STRONG HIGH WILL PASS S OF NEW ENGLAND THU...THEN ANOTHER SHORT WAVE WILL PUSH THROUGH LATE THIS WEEK WITH ANOTHER ROUND OF SNOW SHOWERS. SOME QUESTION HOW THIS HIGH WILL SET UP NEAR OR N OF THE REGION NEXT WEEKEND. KEPT DRY CONDITIONS FOR NOW ALONG WITH SOME MODERATION OF TEMPERATURES THOUGH REMAINING BELOW SEASONAL NORMALS. TUESDAY NIGHT... FAST MOVING CLIPPER LOW WILL PUSH OFFSHORE...TAKING ITS LIGHT SNOW WITH IT. THE LOW DOES LOOK TO DEEPEN WHILE MOVING E...BUT SOME QUESTION AS TO WHETHER THIS MAY ENHANCE THE SNOWFALL SOMEWHAT ACROSS OUTER CAPE COD AND NANTUCKET. OTHERWISE...EXPECT CONDITIONS TO IMPROVE OVERNIGHT THOUGH TEMPS DROP OFF TO THE TEENS AT MOST LOCATIONS...EXCEPT THE LOWER-MID 20S ALONG THE IMMEDIATE COAST. WEDNESDAY... ARCTIC FRONT WILL HEAD SE ACROSS THE REGION DURING THE AFTERNOON AS OVERALL H5 BROAD TROUGH BEGINS TO AMPLIFY. MODELS CONTINUE TO SIGNAL POTENTIAL FOR SCT SNOW SHOWERS AND POSSIBLY A FEW LOCALLY HEAVY SNOW SQUALLS AS THE FRONT MOVES ACROSS WITH PRETTY GOOD LOW LEVEL MOISTURE IN PLACE ALONG WITH H5 SHORT WAVE IN THE DIGGING UPPER FLOW. EXPECT EXCELLENT LOW LEVEL MIXING TO DEVELOP AS ARCTIC AIR BEGINS TO FILTER IN LATE IN THE DAY. W-NW WIND GUSTS TO 30-40 MPH AND TEMPS FALLING INTO THE TEENS AWAY FROM THE COAST BY EVENING. WEDNESDAY NIGHT AND THURSDAY... CORE OF COLDEST AIR WILL DIVE INTO NEW ENGLAND WED NIGHT. VERY STRONG CAA AS H85 TEMPS DROP TO -25C TO -30C OVERNIGHT. EXCELLENT LOW LEVEL MIXING AND DECENT PRES GRADIENT WILL COMBINE TO KEEP NW WIND GUSTS ON ORDER OF 30-40 MPH...POSSIBLY HIGHER ACROSS CAPE COD AND THE ISLANDS. WITH THIS ARCTIC AIRMASS ALONG WITH SOME SNOW COVER IN PLACE...EXPECT TEMPS TO DROP BELOW ZERO ACROSS MOST INTERIOR AREAS AND MAY EVEN FLIRT WITH ZERO IN THE BOSTON AND PROVIDENCE METRO AREAS. DANGEROUSLY LOW WIND CHILLS EXPECTED...AS LOW AS -20 TO -30 OVERNIGHT INTO THU MORNING. WIND CHILL HEADLINES WILL LIKELY BE NEEDED FOR MOST AREAS. MAY ALSO SEE OCEAN EFFECT SNOW SHOWERS LINGERING ACROSS THE OUTER CAPE AND NANTUCKET. CORE OF COLD AIR MOVES OFFSHORE DURING THU WITH TEMPS RISING TO THE TEENS /STILL RUNNING 15 TO 20 DEGREES BELOW SEASONAL NORMS/. THURSDAY NIGHT AND FRIDAY... ANOTHER FAST MOVING SHORTWAVE APPROACHES...WHICH MAY BRING ANOTHER ROUND OF SNOW SHOWERS. WITH THE COLD AIR IN PLACE AND WINDS SHIFTING TO SW...MIGHT SEE SOME S COASTAL OCEAN EFFECT SNOW SHOWERS DEVELOP LATE THU NIGHT INTO FRI BEFORE NEXT SYSTEM MOVES ACROSS. WILL ALSO NEED TO MONITOR FOR POSSIBLE SNOW SQUALLS WITH THE FRONT...THOUGH WINDS BEHIND THIS SYSTEM NOT AS STRONG. SATURDAY AND SUNDAY... SOME QUESTION AS TO HOW THE NEXT HIGH PRES ORIENTS ACROSS THE NORTHEAST OR FURTHER N...AND A POSSIBLE LOW THAT MIGHT DEVELOP IN THE SOUTHERN STREAM. HAVE KEPT CONDITIONS DRY FOR NOW...BUT SOMETHING TO MONITOR. TEMPS ALSO SLOW MODERATE...THOUGH REMAIN BELOW NORMAL. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY/... THIS AFTERNOON...MAINLY VFR AND GUSTY WNW WINDS UP TO 40 KT. LOW RISK OF BRIEF MVFR IN ISOLATED/WIDELY SCATTERED SNOW SHOWERS/SQUALLS. MODERATE FORECAST CONFIDENCE. TONIGHT...ANY LINGERING SNOW SHOWERS/SQUALLS AT SUNSET FIZZLE AND/OR EXIT THE SOUTH COAST AND GIVE WAY TO VFR/DRY WEATHER ALONG WITH DIMINISHING WINDS. HIGH FORECAST CONFIDENCE. TUESDAY...MARGINAL VFR-MVFR IN MAINLY LIGHT SNOW. FAIRLY LIGHT WINDS. MODERATE FORECAST CONFIDENCE. KBOS TERMINAL...ONLY UNCERTAINTY IN FORECAST IS EXACT TIMING OF POTENTIAL SNOW SHOWERS/SQUALLS INCLUDING AREAL COVERAGE AND INTENSITY. KBDL TERMINAL...ONLY UNCERTAINTY IN FORECAST IS EXACT TIMING OF POTENTIAL SNOW SHOWERS/SQUALLS INCLUDING AREAL COVERAGE AND INTENSITY. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...MODERATE CONFIDENCE. TUE NIGHT...MAINLY VFR CIGS. MAY SEE LOCAL MVFR CONDITIONS LINGER ACROSS CAPE COD AND NANTUCKET AS LIGHT SNOW LINGERS. WED...MAINLY VFR CIGS. MAY SEE BRIEF PERIODS OF MVFR-IFR CIGS/VSBYS IN LOCALLY HEAVY SNOW SQUALLS ALONG ARCTIC FRONT WED AFTERNOON/EVENING. EXPECT NW WINDS TO INCREASE WED AFTERNOON... GUSTING TO 30-40 KT AND CONTINUING INTO WED NIGHT. THU...VFR. DIMINISHING WIND. THU NIGHT AND FRI...MAINLY LOW END VFR CONDITIONS BUT WILL SEE PATCHY MVFR DEVELOPING IN SCT SNOW SHOWERS. OCEAN EFFECT SNOW POSSIBLE ALONG THE S COAST. GUSTY SW WINDS DEVELOPING LATE THU NIGHT AND FRI WITH GUSTS TO 30-35 KT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH TUESDAY/...MODERATE TO HIGH CONFIDENCE. THIS AFTERNOON...WNW GALES WITH A LOW RISK OF A FEW SNOW SHOWER/SQUALLS...GREATER RISK OFFSHORE. ROUGH SEAS SOUTH COAST FROM LEFTOVER SSW SWELLS COMBINED WITH LONGER WESTERLY FETCH FOR WIND WAVES. TONIGHT...WINDS DIMINISH AS HIGH PRES BUILDS OVER NEW ENGLAND. TUESDAY...LIGHT WINDS WITH LOWERING SEAS. VSBY MAY LOWER IN PERIODS OF LIGHT SNOW/FLURRIES. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE. TUESDAY NIGHT...WINDS AND SEAS BELOW SCA. REDUCED VSBYS IN LIGHT SNOW. WED AND THU...STRONG COLD ADVECTION WILL LIKELY RESULT IN ANOTHER PERIOD OF NW GALES LATE WED THROUGH WED NIGHT...LINGERING INTO THU MORNING BEFORE WINDS BRIEFLY DIMINISH. MODERATE FREEZING SPRAY DEVELOPING WED NIGHT INTO THU AS ARCTIC AIR MOVES OVER THE WATERS. THU NIGHT AND FRI...ANOTHER PERIOD OF GALES LIKELY LATE THU NIGHT INTO FRI ON SW FLOW. GUSTS TO 40 KT POSSIBLE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR CTZ002>004. MA...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ002>024-026. RI...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR RIZ001>008. MARINE...GALE WARNING UNTIL 10 PM EST THIS EVENING FOR ANZ230>235-237- 254>256. GALE WARNING UNTIL 6 PM EST THIS EVENING FOR ANZ236. GALE WARNING UNTIL 1 AM EST TUESDAY FOR ANZ250-251. && $$ SYNOPSIS...NOCERA/EVT NEAR TERM...NOCERA/EVT/NMB SHORT TERM...NOCERA LONG TERM...EVT AVIATION...NOCERA/EVT/NMB MARINE...NOCERA/EVT/NMB
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
345 PM EST MON JAN 5 2015 .DISCUSSION... TONIGHT-TUESDAY... QUIET WX PATTERN IN STORE FOR CENTRAL FL AS THE COLD FRONT STALLS AND WASHES OUT OVER THE S PENINSULA. LATEST RUC ANALYSIS SHOWS A VERY STABLE H85-H70 LYR WITH LAPSE RATES BLO 4.0C/KM...AS LOW AS 2.5C/KM DIRECTLY OVERHEAD JUST S OF THE I-4 CORRIDOR. VERY LOW ENERGY AIRMASS OVERHEAD AND UPSTREAM WITH NO SIG MID LVL VORT/OMEGA MAXES...WEAK UPR LVL DIVERGENCE OVER THE NRN GOMEX/FL BIG BEND WILL ONLY GENERATE MID/UPR LVL CLOUD COVER AT BEST. RADAR HAS INDICATED A FEW SPRINKLES IN THE IMMEDIATE VCNTY OF THE FRONT THIS AFTN...BUT EVEN THESE HAVE DISSIPATED OVER LAND NOW THAT THE FRONT HAS PUSHED S OF THE LAKE. WEAK BUT STUBBORN RIDGING OVER THE NRN BAHAMAS/FL STRAITS WILL BE REINFORCED BY AN ANTICYCLONE OVER THE NW GULF COAST. THIS WILL EFFECTIVELY BLOCK OUT ANY OF THE PENCIL THIN VORT ENERGY NOTED OVER THE NRN GULF COAST. ANY ADDITIONAL PRECIP WILL BE LIMITED TO THE GULF STREAM AND SHOULD DISSIPATE BY SUNSET...WILL KEEP THE FCST DRY. MIN TEMPS WILL HAVE A FAIRLY WIDE SPREAD TONIGHT DESPITE THINNING CLOUD COVER AS THE POST FRONTAL HI PRES RIDGE EXTENDING FROM THE RIO GRANDE VALLEY TO THE GREAT LAKES PRESSES EWD AND WEAKENS. SFC WINDS EXPECTED TO VEER TO AN ONSHORE COMPONENT NEAR THE COAST...KEEPING THE SPACE/TREASURE COASTS IN THE L/M60S. LIGHTER WINDS AND COOLER SHELF WATERS OFF VOLUSIA COUNTY WILL ALLOW TEMPS TO FALL INTO THE M/U50S. OVER THE INTERIOR...NRLY WINDS BCMG LIGHT AND VARIABLE AS THE PGRAD WEAKENS...SHOULD GIVE WAY TO A LIGHT DRAINAGE FLOW THAT WILL ALLOW MINS TO FALL INTO THE L50S N OF THE I-4 CORRIDOR...M/U50S TO THE S...NEAR 60 ALONG THE N SHORE OF LAKE OKEECHOBEE. LIMITED COOL AIR ADVECTION HAS OCCURRED WITH THIS FRONT...SFC DEWPOINTS IN THE M/U40S N OF I-4 INCREASE TO THE M/U50S JUST S OF IT...AND REMAIN IN THE L60S ALONG THE TREASURE COAST AND N SHORE OF LAKE OKEECHOBEE. DESPITE A LIGHT NW FLOW THAT WILL DVLP BY MIDDAY... THE HIGH DEWPOINTS WILL ALLOW MAX TEMPS TO WARM INTO THE L/M70S N OF I-4...AND INTO THE M/U70S TO THE SOUTH. WED/WED NIGHT... UPPER LEVEL TROUGH DIGS SOUTHWARD ACROSS THE EASTERN U.S. AS STRONG ARCTIC HIGH PRESSURE BUILDS DOWN FROM THE NORTHERN PLAINS INTO THE MID-MISSISSIPPI VALLEY REGION. THIS LEADS TO A DRY COLD FRONTAL PASSAGE ACROSS CENTRAL FLORIDA WITH COOL NORTHWEST FLOW AND INCREASING HIGH CLOUDINESS DURING THE DAY. HIGHS WILL BE MID TO UPPER 60S ORLANDO NORTH AND LOW TO MID 70S TREASURE COAST. STRONG COLD AIR ADVECTION OCCURS WED NIGHT OVER THE INTERIOR BUT MODELS SHOW QUICK VEERING OF THE 925-850 MB FLOW TO ONSHORE. THIS SHOULD PRODUCE A TIGHT COASTAL/INLAND TEMP GRADIENT WED NIGHT/THU MORNING...RANGING FROM THE MID 30S IN PORTIONS OF LAKE COUNTY TO THE LOWER 50S IMMEDIATE COAST SOUTH OF THE CAPE. IT STILL APPEARS THAT FREEZING TEMPERATURES WILL REMAIN NORTH OF OUR FA BUT NORTH WINDS 15-20 MPH WILL PRODUCE WIND CHILL VALUES BELOW FREEZING NORTH AND WEST OF ORLANDO. SO WILL PROBABLY NEED A WIND CHILL ADVISORY THERE. THU-SUN... STRONG HIGH PRESSURE BUILDS INTO THE SOUTHEAST THU AND EXTENDS OFFSHORE INTO LATE WEEK WITH LOW LEVEL NORTHERLY FLOW BECOMING ONSHORE. ELEVATED NE FLOW ABOVE THE SFC THU WILL TRANSPORT MARINE STRATOCU CLOUDS ONSHORE WITH ISOLATED COASTAL SHOWERS EXPECTED. TEMPS WILL REMAIN BELOW NORMAL INTO LATE WEEK WITH HIGHS THU IN THE 50S NORTH OF MELBOURNE AND LOW-MID 60S SOUTH. MAX TEMPS FRI WILL RANGE FROM THE 60S MOST AREAS TO LOW 70S ACROSS PORTIONS OF THE TREASURE COAST. THEN INTO THE WEEKEND STRENGTHENING ONSHORE LOW LEVEL FLOW WILL GRADUALLY WARM TEMPS WITH RAIN CHANCES INCREASING TO 20-30 PERCENT. && .AVIATION...THRU 06/18Z SFC WNDS: THRU 06/03Z...N/NE 8-14KTS...OCNL G22KTS CSTL SITES. BTWN 06/03Z-06/15Z...N/NW AOB 5KTS. AFT 06/15Z...NW 5-8KTS. VSBYS/WX: BTWN 06/09Z-06/13Z...LCL MVFR BR. CIGS: N OF KVRB-KOBE THRU 06/12Z...BTWN FL060-080 LCL BTWN FL020-030...AFT 06/12Z AOA FL120. S OF KVRB-KOBE...THRU 06/06Z BTWN FL040-060 AREAS BTWN FL010-020...AFT 06/06Z BTWN FL020-030...LCL BLO FL010 THRU 06/12Z. && .MARINE... TONIGHT-TUESDAY...CHOPPY/ROUGH CONDITIONS MEASURED BY THE LCL BUOY NETWORK...NEAR SCA CONDITIONS MEASURED BY THE CANAVERAL DATA BUOYS WITH NRLY WINDS ARND 20KTS AND SEAS BTWN 5-7FT...SCRIPPS BUOYS LOWER AT 3-5FT...BUT ALL RECORDING NEAR SQUARE SEAS WITH DOMINANT PDS BTWN 5-6SEC. MODERATE TO FRESH NRLY BREEZE BEHIND A COLD FRONT JUST S OF LAKE OKEECHOBEE WILL DIMINISH OVERNIGHT AS THE POST FRONTAL RIDGE OVER THE OH/TN/MS RIVER VALLEYS PUSHES TOWARD THE ERN SEABOARD AND WEAKENS...SFC WINDS BCMG A LIGHT TO GENTLE ERLY BREEZE BY DAYBREAK. LCL PGRAD WILL COLLAPSE AS THE FRONT WASHES OUT IN THE VCNTY OF LAKE OKEECHOBEE...ALLOWING SFC/BNDRY LYR WINDS BCMG LGT/VRBL BY LATE TUE MRNG. WINDS WILL THEN BACK TO THE N/NW AND INCREASE TO ARND 10KTS BY SUNSET AS THE LEADING EDGE OF A NEW HIGH PRES RIDGE BEGINS TO NUDGE ITS WAY INTO THE DEEP SOUTH. GIVEN THE CURRENT CONDITIONS...CURRENT NEARSHORE CAUTION/OFFSHORE ADVISORY WILL CONTINUE THRU 10PM THIS EVNG. WED-FRI...STRONG AREA OF HIGH PRESSURE BUILDS DOWN FROM THE NORTHERN PLAINS MID WEEK INTO THE SOUTHEAST U.S. BY THU-FRI. A COLD FRONT WILL MOVE THROUGH THE WATERS WED WITH NORTHERLY WINDS QUICKLY INCREASING BEHIND THE BOUNDARY INTO WED NIGHT. THIS WILL LEAD TO VERY HAZARDOUS BOATING CONDITIONS ACROSS THE WATERS WITH WIND SPEEDS 25-30 KTS BUILDING SEAS UP TO 14 FEET IN THE GULF STREAM WED NIGHT/THU. WINDS BEGIN TO DECREASE BUT REMAIN HAZARDOUS AS THEY VEER TO THE NORTHEAST THU AFTN WITH A CONTINUED DECREASE FORECAST THU NIGHT-FRI. SEAS WILL BE SLOW TO SUBSIDE INTO LATE WEEK WITH 7 FT SEAS IN THE GULF STREAM STILL FORECAST ON FRI. && .FIRE WEATHER... DRIER AIR BUILDING INTO THE AREA WEDNESDAY WILL GENERATE MIN RH VALUES BETWEEN 25 AND 30 PERCENT ACROSS NORTHERN AND INTERIOR SECTIONS WEDNESDAY. NW WINDS WILL BE AROUND 10 MPH. && .PRELIMINARY POINT TEMPS/POPS... DAB 51 71 47 65 / 10 10 0 10 MCO 53 77 51 67 / 10 10 10 10 MLB 59 76 57 69 / 10 0 10 10 VRB 62 78 57 71 / 10 0 10 10 LEE 49 72 47 65 / 10 10 0 10 SFB 52 75 49 66 / 10 10 10 10 ORL 53 76 51 66 / 10 10 10 10 FPR 62 78 58 72 / 10 0 10 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR 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/AVIATION...BRAGAW LONG TERM/IMPACT WX...KELLY
AREA FORECAST DISCUSSION
NWS MIAMI FL
1252 PM EST MON JAN 5 2015 .AVIATION... WEAK COLD FRONT GRINDING TO A HALT ACROSS THE LAKE REGION, CURRENTLY. THE EVENTUAL RESTING PLACE OF THIS BOUNDARY WILL DETERMINE IF OR WHEN MVFR CIGS DEVELOP DURING THE FORECAST. THE TYPICALLY PESSIMISTIC LAMP GUIDANCE KEEPS CIGS ABV MVFR UNTIL LATE TONIGHT, ALTHOUGH IS CURRENTLY MISSING CEILINGS AT KPBI. VERY WELL COULD BE A FEW HOURS OF MVFR CIGS AT THE NORTHERN TERMINALS THIS PM, BUT ANY LOWER CIGS FROM THE FRONT SHOULD STAY AWAY FROM MORE SOUTHERN TERMINALS. FAIR INGREDIENTS FOR MVFR OR EVEN IFR CIGS AT APF LATE TONIGHT, WITH THE BOUNDARY NEARBY. ALTHOUGH THE LAMP INDICATES CHC EXISTS FOR MVFR CIGS AT OTHER TERMINALS LATE TONIGHT, WILL KEEP ABV FOR NOW. IF THEY DEVELOP, SOME LOWER CIGS COULD PERSIST INTO TUESDAY DEPENDING UPON WHERE THE DIFFUSE BOUNDARY RESIDES. && .PREV DISCUSSION... /ISSUED 953 AM EST MON JAN 5 2015/ UPDATE... CURRENT ANALYSIS SHOWS DEEP LAYER RIDGE STRETCHING ACROSS THE EXTREME SOUTHERN PORTION OF THE PENINSULA WITH A WEAK COLD FRONT NEAR THE SOUTHERN SHORES OF LAKE OKEECHOBEE INCLUDING EXTREME NORTHERN PALM BEACH AND HENDRY COUNTIES ALONG WITH GLADES COUNTY. THE FRONT IS VERY SHALLOW AND IS MARKED BY A NEAR SOLID DECK OF LOW STRATUS BEHIND THE LEADING EDGE OF THE BOUNDARY. THE FRONT WILL NOT MAKE FURTHER PROGRESS SOUTHWARD STALLING NEAR ITS CURRENT POSITION AND THEN BECOMING DIFFUSE AS THE MAIN UPPER TROUGH LIFTS WELL TO THE NORTHEAST. THIS WILL LEAVE MOST OF SOUTH FLORIDA IN THE WARM SECTOR THIS AFTERNOON AND WITH DEW POINTS IN THE UPPER 60S TO AROUND 70, HIGH RESOLUTION SHORT TERM MODEL GUIDANCE SUGGEST A FEW SHOWERS OVER THE INTERIOR AND EAST COASTAL ZONES. THE 12Z MFL SOUNDING ALSO SHOWS THE LOW LEVEL MOISTURE INCREASING FROM YESTERDAY BUT THE STRONG SUBSIDENCE CAP WITH ITS BASE AT 7-8K WILL KEEP THE SHOWERS LOW TOPPED. KOB PREV DISCUSSION... /ISSUED 624 AM EST MON JAN 5 2015/ AVIATION... LIGHT TO MODERATE SHOWERS CONTINUE IN THE VICINITY OF ALL THE ATLANTIC COAST TERMINALS AROUND 11Z AND ARE NEARLY STATIONARY. BRIEF PERIODS OF NEAR MVFR CEILINGS ARE POSSIBLE THROUGH ABOUT 13Z AS THE SHOWERS ARE NEARLY STATIONARY. OTHERWISE...MAINLY VFR CONDITIONS EXPECTED LATER THIS MORNING AND THIS AFTERNOON. WINDS THIS MORNING ARE EXPECTED TO BE LIGHT AND VARIABLE WITH NORTHEASTERLY WINDS BUILDING INTO THE REGION AROUND 18Z AHEAD OF A COLD FRONT IN NORTH CENTRAL FLORIDA. PREV DISCUSSION... /ISSUED 404 AM EST MON JAN 5 2015/ DISCUSSION... A COLD FRONT IS CURRENTLY MAKING ITS WAY TOWARDS SOUTH FLORIDA AS EXPECTED. IT IS CURRENTLY IN CENTRAL FLORIDA. AHEAD OF IT SOME SHOWER ACTIVITY HAS ALREADY DEVELOPED, MAINLY ALONG THE ATLANTIC COASTLINE. THE HRRR DOES SHOW THIS ACTIVITY ENDING OVER THE NEXT COUPLE OF HOURS. SO, CONTINUE WITH SLIGHT CHANCE POPS OVER COASTAL PALM BEACH COUNTY TO COVER ANY SHOWER ACTIVITY THAT PERSISTS. ANOTHER CONCERN WITH THIS LINE OF CONVERGENCE ALONG THE COAST IS WATERSPOUT ACTIVITY. ALTHOUGH THE BOUNDARY IS NOT PROMINENT ON THE GULF COAST, CAN NOT RULE ONE OUT ACROSS ANY OF THE SOUTH FLORIDA WATERS THIS MORNING. COMPARING LAST NIGHTS SOUNDING AND THE WATER VAPOR IMAGERY, THE MOISTURE LOOKS TO BE FAIRLY SHALLOW. THE SOUNDING SHOWS A STRONG CAP IS IN PLACE AT AROUND 800MB. NAM MODEL SOUNDINGS SHOW IT SHOULD HOLD, EVEN WITH THE FRONT APPROACHING. THE WATER VAPOR IMAGERY IS SHOWING THAT THE MOISTURE IS REMAINING MAINLY OVER NORTH FLORIDA AND SOUTH GEORGIA, WITH LITTLE PROGRESSION TO THE SOUTH. SO, THIS WILL LEND CREDENCE TO THE LOW POPS THE MODELS ARE FORECASTING FOR TODAY, WITH A LOW END CHANCE OVER THE A PORTION OF THE CWA THIS AFTERNOON. THE FRONT WILL SLOWLY PROGRESS TO THE SOUTH, THROUGH THE CWA TODAY, AS THE MAIN LOW IS WELL AWAY FROM THE AREA, NORTHEAST OF MAINE, AND PULLING AWAY. MODELS SHOW THE FRONT WILL MAKE IT THROUGH MOST OF SOUTH FLORIDA AND PERHAPS TO THE KEYS BEFORE STALLING OUT. IT WILL THEN REMAIN THROUGH WEDNESDAY AS A WEAK BOUNDARY, KEEPING A SLIGHT CHANCE OF SHOWERS IN THE FORECAST FOR PORTIONS OF THE CWA UNTIL WEDNESDAY EVENING. EVEN THAT WILL BE MORE OR LESS ALONG THE ATLANTIC COAST AND OVER THE ATLANTIC WATERS. HIGH PRESSURE WILL BUILD IN OVER THE SOUTH EASTERN US, BUT NEVER DIG FAR ENOUGH SOUTH TO PUSH THE FRONT AWAY FROM THE AREA. MEANWHILE, ANOTHER LOW WILL MOVE OUT OF THE ROCKIES TODAY AND QUICKLY MOVE INTO THE PLAINS. MODELS INDICATE IT SHOULD BE OVER THE MISSISSIPPI VALLEY TONIGHT AND THEN APPEAR TO WASH OUT AS IT MOVES ACROSS THE APPALACHIANS. MODELS SHOW IT WILL REFORM OFF THE MID ATLANTIC COAST TUESDAY NIGHT AND BEGIN TO INTERACT WITH THE STALLED BOUNDARY. AS IT DOES, AS VERY STRONG HIGH WILL MOVE OUT OF WESTERN CANADA AND INTO THE PLAINS. THIS HIGH WILL WORK WITH THE LOW TO PUSH THE FRONT OUT OF THE AREA WEDNESDAY NIGHT AND WILL MOVE COOLER, DRIER AIR INTO SOUTH FLORIDA BY THURSDAY MORNING. HOWEVER, EVEN THOUGH IT WILL BE A SIGNIFICANT COOL DOWN, IT WILL NOT BE ENOUGH TO WARRANT ANY HEADLINES. LOWS THURSDAY LOOK TO BE IN THE MID 40S FOR THE INTERIOR LAKE REGION TO THE UPPER 50S ALONG THE ATLANTIC COAST. THE GULF COAST LOOKS TO BE IN THE UPPER 40S TO LOW 50S. HIGHS THURSDAY WILL RANGE FROM THE LOW 60S IN THE LAKE REGION TO AROUND 70 IN THE MIAMI AREA. THIS HIGH IS VERY TRANSIENT AND WILL BE GONE BY THE WEEKEND. THIS WILL ALLOW TEMPERATURES TO QUICKLY REBOUND AND COASTAL SHOWERS TO MAKE A RETURN POSSIBLY BY FRIDAY. THE FLOW WILL CONTINUE TO BE EASTERLY, SO THE ATLANTIC COAST LOOKS TO HAVE THE BEST CHANCE FOR SHOWER ACTIVITY. BY THE END OF THE WEEKEND, SOUTH FLORIDA WILL BE BACK UNDER THE WESTERN EDGE OF AN UPPER LEVEL RIDGE AND STILL IN EASTERLY SFC FLOW. MODELS ARE SHOWING A CHANCE FOR SHOWERS ACROSS THE AREA BY SUNDAY. AVIATION... ALTHOUGH THE RECENT COMPUTER MODEL GUIDANCE DOES NOT INDICATE MUCH IN THE WAY OF IFR VISIBILITY OR CEILING RESTRICTIONS OR MUCH POTENTIAL FOR WIDESPREAD FOG DEVELOPMENT THIS MORNING...CONDITIONS COULD BE FAVORABLE FOR LOW STRATUS AND/OR AREAS OF FOG AS A COLD FRONT CONTINUES TO MOVE INTO NORTHERN FLORIDA. ALL TAF SITES HAVE BEEN ASSIGNED PERIODS OF MVFR VISIBILITY RESTRICTIONS FROM 09Z TO 12Z THIS MORNING. BRIEF PERIODS OF NEAR IFR CONDITIONS MAY BE POSSIBLE AND WILL HAVE TO AMEND IF/WHEN CONDITIONS WARRANT. REGIONAL WINDS ARE EXPECTED TO BE LIGHT AND SOMEWHAT VARIABLE AT TIMES. MARINE... SHOWER ACTIVITY WILL BE POSSIBLE TODAY AS A COLD FRONT SLOWLY MOVES THROUGH THE AREA. WINDS WILL SLOWLY TURN TO THE NORTH AND NORTHEAST TODAY. THERE IS A SLIGHT CHANCE OF A WATERSPOUT, MAINLY ALONG A CONVERGENCE LINE ALONG THE ATLANTIC COAST THIS MORNING. THE FRONT WILL STALL JUST TO THE SOUTH, KEEP A SLIGHT CHANCE OF SHOWERS THROUGH WEDNESDAY. WEDNESDAY NIGHT, A STRONG HIGH WILL BUILD IN, BRINGING BREEZY CONDITIONS AND BUILDING SEAS FOR THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 70 80 67 77 / 20 20 20 10 FORT LAUDERDALE 72 80 69 78 / 20 20 10 10 MIAMI 71 82 69 79 / 20 10 10 10 NAPLES 65 81 64 75 / 10 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...13/SI LONG TERM....13/SI AVIATION...21/KM
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
326 PM CST MON JAN 5 2015 .SHORT TERM... 302 PM CST TONIGHT... SYNOPTIC/FORCING DISCUSSION...WATER VAPOR IMAGERY SHOWS THE APPROACHING UPPER TROUGH QUICKLY MOVING ACROSS THE NORTHERN PLAINS WITH THE ATTENDANT SFC LOW MOVING ALONG THE CENTRAL SOUTH DAKOTA/NEBRASKA BORDER. SNOW CONTINUES TO SPREAD EASTWARD ACROSS IOWA WITH A WARM ADVECTION RIBBON EXTENDING EAST-SOUTHEAST INTO CENTRAL ILLINOIS. MANY SITES ACROSS IOWA ARE REPORTING 1/4 TO 1/2SM VSBY WITH STRONG REFLECTIVITY ON THE RADAR MOSAIC. GROUND REPORTS THUS FAR INDICATE INCH PER HOURS AMOUNTS WITH NEAR 0.10 INCH LIQUID LEADING TO 10-11:1 SNOW RATIOS. LATEST NEAR TERM GUIDANCE TRENDS SHOW THAT THE BEST FGEN FORCING WILL TRACK ACROSS THE SOUTHERN THIRD TO HALF OF THE ARA THIS EVENING CONTINUING TO SUPPORT THE IDEA THAT THAT IS WHERE THE HEAVIEST SNOW WILL FALL. HEAVIEST LIQUID SHOULD FALL JUST NORTH OF THE LOW TRACK WHICH WILL BE TO THE SOUTH OF THE CWA. FORECAST SOUNDINGS CONTINUE TO SHOW A DEEP SNOW GROWTH ZONE BUT ALIGNMENT OF BEST ASCENT VARIES ACROSS THE AREA. NORTHERN AREAS ENTRENCHED IN THE DEEPER COLD AIR WILL SEE THE BULK OF THE FORCING ABOVE THE BEST SNOW GROWTH ZONE WHILE AREAS SOUTH SEE A BETTER ALIGNMENT. THIS MAY BE WHAT IS OCCURRING ACROSS CENTRAL IOWA WHERE LOWER RATIOS HAVE BEEN REPORTED THUS FAR /SMALLER FLAKE SIZE AND LESS FLUFF TO ACCUMULATION/. ACCUMULATION/TIMING DISCUSSION...WITH SNOW QUICKLY PROGRESSING EASTWARD HAVE BUMPED UP POPS AFTER 22Z IN THE SOUTHWEST CWA. SOUTHWEST AREAS WILL LIKELY SEE A QUICK RAMP UP IN INTENSITY BY AROUND 00Z WITH A 4-5 HOUR WINDOW OF STRONG FORCING BEFORE THINGS TAPER AROUND AND AFTER 06Z. MOST AREAS WILL SEE A 3-5 HOUR WINDOW FOR SNOW BEFORE THINGS QUICKLY EXIT TO THE SOUTHEAST OVERNIGHT. WILL CONTINUE WITH THE EXPECTATION OF 15-18:1 RATIOS FOR NOW. BEST FORCING...ALIGNMENT OF FORCING WITHIN THE SNOW GROWTH ZONE...AND DURATION OF FORCING CONTINUE TO BE ALIGNED OVER THE FAR SOUTHERN CWA WITH THESE ELEMENTS LESS ALIGNED TO THE NORTH. WITH THIS IN MIND HAVE TIGHTENED UP THE ACCUMULATION GRADIENT ACROSS THE AREA SOMEWHAT TO SHOW A LITTLE BIT LESS IN FAR NORTHEAST IL. AREAS GENERALLY ALONG AND SOUTH OF A MENDOTA TO SOUTH CHICAGO METRO TO RENSSELAER LOOK TO SEE SNOW FALL ACCUMULATION RATES OF AROUND 1 INCH PER HOUR LEADING TO A BROAD AREA OF 3 TO 6 INCH TOTALS WITH AREAS ALONG A AND SOUTH OF A STREATOR TO WATSEKA TO FOWLER LINE SEEING THE BEST CHANCE FOR EVEN 5 TO 7 INCHES. HEADLINE AND IMPACTS DISCUSSION...WILL CONTINUE WITH THE WINTER WEATHER ADVISORY FOR THE BULK OF THE AREA GIVEN EXPECTED AMOUNTS. HAVE MADE AN EARLY UPGRADE TO A WINTER STORM WARNING IN THE FAR SOUTH GIVEN THE EXPECTED BETTER BANDING AND BETTER ALIGNMENT OF FORCING ETC. DISCUSSED ABOVE. SNOWFALL INTENSITY/ACCUMULATION RATE WILL BE THE BIGGEST IMPACT WITH RATES AROUND AN INCH PER HOUR AND POSSIBLY TOWARDS 1.5 IN/HR IN THE FAR SOUTH MAKING SNOW REMOVAL DIFFICULT...NOT TO MENTION LIMITING VISIBILITY TO A QUARTER MILE OR LESS AT TIMES. DESPITE LIGHTER AMOUNTS ACROSS THE NORTHERN CWA STILL EXPECT A DECENT ACCUMULATION RATE LEADING TO TRAVEL HAZARDS. MDB && .LONG TERM... 325 PM CST TUESDAY THROUGH THURSDAY...EXPECT THE SNOW TO BE EAST OF THE AREA BY TUESDAY MORNING. WINDS WILL SHIFT TO THE NORTH THEN QUICKLY TO THE WEST. IT IS POSSIBLE THAT SOME LAKE SNOW SHOWERS COULD ORGANIZE ENOUGH TO IMPACT PORTER COUNTY FOR A VERY SHORT TIME BEFORE DAYBREAK BUT THEY WOULD QUICKLY END. HIGH PRESSURE WILL BE IN PLACE ACROSS THE CENTRAL PLAINS BUT A REINFORCING HIGH OVER WESTERN CANADA WILL QUICKLY MERGE WITH IT INTO WEDNESDAY. BY THIS TIME...A BROAD UPPER TROUGH WILL BE IN PLACE ACROSS THE EASTERN TWO-THIRDS OF THE CONUS. ANOTHER TROUGH AXIS WILL BE DROPPING SOUTHWARD TUESDAY EVENING. IT WILL BE QUITE SHEARED OUT BUT THERE MAY BE ENOUGH LIFT IN THE INCREASINGLY COLD AIR TO GENERATE SOME FLURRIES. THE MAIN ISSUE WILL BE EXTREMELY COLD AIR. WITH THE AREA BETWEEN LOW PRESSURE TO THE EAST AND THE BUILDING HIGH TO THE WEST BREEZY WETS TO NORTHWEST WINDS WILL DEVELOP LATER TUESDAY AND CONTINUE INTO WEDNESDAY NIGHT BEFORE DIMINISHING AND SHIFTING SOUTHWEST. THE INITIAL ISSUE WILL BE BLOWING SNOW AND REDUCED VSBY LEADING TO HAZARDOUS TRAVEL SO WILL NEED TO ASSESS THE NEED FOR A WINTER WEATHER ADVISORY FOR THIS LATER TUESDAY INTO AT LEAST WEDNESDAY. TEMPS WILL FALL TO TO THE SINGLE DIGITS BELOW ZERO TUESDAY NIGHT WITH LITTLE RECOVERY WEDNESDAY...THEN FALL TO -5 TO -15 OR SO WEDNESDAY NIGHT. WILL NEED WIND CHILL HEADLINES FROM TUESDAY NIGHT THROUGH THURSDAY MORNING. AFTER COORDINATION WITH NEIGHBORS WILL HOLD OFF ON THIS FOR NOW DUE TO THE ARRIVING SNOW EVENT. MOST AREAS OF ILLINOIS LOOK TO MEET WARNING CRITERIA AND SOUTHERN AREAS AND NORTHWEST INDIANA MAY BE IN HIGH END ADVISORY CRITERIA. OVERALL EXPECT WIND CHILLS OF -20 TO AROUND -35 DURING THIS PERIOD WITH LITTLE IMPROVEMENT DURING THE DAY WEDNESDAY. THURSDAY THROUGH THE WEEKEND...THE SURFACE HIGH WILL PASS THURSDAY ALLOWING A SOUTHWESTERLY FLOW TO DEVELOP. THIS WILL COMBINE WITH ANOTHER APPROACHING SYSTEM FORM THE NORTHWEST WHICH WILL ALLOW FOR SOME MODEST WARMING...LEADING TO A NOTICEABLE MODERATION OF TEMPS TO THE TEENS. THE PASSING TROUGH MAY EXTEND FAR ENOUGH SOUTH TO PRODUCE SOME LIGHT SNOW LATER THURSDAY BUT WILL NEED TO FURTHER EVALUATE THIS. THINGS COOL SLIGHTLY FOR FRIDAY BUT THE BIG TROUGH LOOKS TO SHIFT EAST INTO THE WEEKEND. THIS WILL ALLOW FOR MORE OF A ZONAL FLOW RESULTING IN A MODERATION OF TEMPS. EMBEDDED WAVES MAY BRING SOME CHANCES FOR PRECIP AS WELL. MDB && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * ONSET TIMING OF SNOW EARLY THIS EVENING...AND PERIOD OF THE LOWEST VIS AND CIGS IN SNOW THIS EVENING. * POTENTIAL FOR A SLIGHTLY EARLIER ONSET OF SNOW EARLY THIS EVENING. KJB //DISCUSSION...UPDATED 18Z... A QUICK MOVING WEATHER DISTURBANCE WILL SPREAD SNOW ACROSS THE REGION BY THIS EVENING. THE SNOW WILL LIKELY BE MODERATE TO HEAVY IN INTENSITY...WITH VISIBILITIES LIKELY FALLING UNDER A MILE WITHIN THE HEAVIEST SNOW. DUE TO THE FAST MOVEMENT OF THIS SYSTEM...THERE WILL ONLY BE ABOUT A 6 TO 8 HOUR WINDOW OF SNOWFALL...WITH THE HEAVIEST SNOW RATES...UP TO AN INCH PER HOUR...OCCURRING DURING A 2 TO 3 HOUR PERIOD BETWEEN ABOUT 03 AND 05-06 UTC THIS EVENING. WE CURRENTLY EXPECT THE SNOW TO ONSET AROUND OR JUST AFTER 00 UTC THIS EVENING AT KRFD...AND AROUND OR SHORTLY AFTER THE 01-02 UTC TIME FRAME ACROSS THE EASTERN TERMINALS. THE SNOW SHOULD END FROM WEST TO EAST OVERNIGHT PRIOR TO DAYBREAK TUESDAY. IFR CIGS AND LIFR VISIBILITIES ARE LIKELY DURING THE PERIOD OF HEAVIEST SNOW...WITH CONDITIONS RAPIDLY IMPROVING EARLY TUESDAY MORNING. WINDS WILL REMAIN FAIRLY LIGHT OUT OF THE SOUTHWEST THIS EVENING...THEN BECOME MORE NORTHWESTERLY BY DAYBREAK TUESDAY. KJB //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM WITH ONSET TIMING OF SNOW THIS EVENING...WITH A POSSIBILITY OF A SLIGHTLY EARLIER ONSET. * MODERATE WITH TIMING OF LOWEST CIGS/VSBYS IN SNOW LATER THIS EVENING. KJB //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY...IMPROVING TO VFR. WEDNESDAY...VFR. THURSDAY...PRIMARILY VFR. GUSTY SOUTHWEST WINDS. FRIDAY...PRIMARILY VFR. SATURDAY...CHANCE OF SNOW. SUNDAY...CHANCE OF SNOW EARLY. BEACHLER && .MARINE... 319 PM CST THE ROGER BLOUGH WHICH HAS BEEN COMING DOWN THE WISCONSIN SIDE OF THE LAKE AND IS CROSSING THE SOUTH END HAS BEEN REPORTING WAVES AROUND 5 FT THIS AFTERNOON. THESE WAVES SHOULD BE SUBSIDING SLIGHTLY OVERNIGHT AS HIGH PRESSURE MOVES ACROSS THE SOUTH END OF THE LAKE AND IS FOLLOWED BY A WEAK LOW...ALLOWING WINDS TO CONTINUE TO DIMINISH FROM EARLIER GALES. WAVES BUILD AGAIN TOMORROW AS WEST WINDS INCREASE AHEAD OF THE NEXT APPROACHING HIGH. MORE SUBSTANTIAL WAVE GROWTH OCCURS TUESDAY NIGHT INTO WEDNESDAY AS THE STRONG HIGH PRESSES INTO THE MIDWEST AND WINDS INCREASE CONSIDERABLY FROM THE NORTHWEST. HEAVY FREEZING SPRAY WILL ALSO BE A CONCERN STARTING LATE TUESDAY AND CONTINUING AT LEAST INTO WEDNESDAY AFTERNOON WITH BITTERLY COLD AIR AND STRONG NORTHWEST GUSTS. AFTER THE GALE AND FREEZING SPRAY EVENT TOWARD MIDWEEK...THE REMAINDER OF THE WEEK BRINGS CONTINUED CHANCES FOR STRONG WINDS AND HIGH WAVES ON THE LAKE...THOUGH THE AIR WILL NOT BE AS COLD. LENNING && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WINTER STORM WARNING...ILZ032-ILZ033-ILZ039 UNTIL 6 AM TUESDAY. WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008- ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021- ILZ022-ILZ023 UNTIL 6 AM TUESDAY. IN...WINTER WEATHER ADVISORY...INZ001-INZ002-INZ010-INZ011 UNTIL 6 AM TUESDAY. WINTER STORM WARNING...INZ019 UNTIL 6 AM TUESDAY. LM...GALE 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...6 PM TUESDAY TO 3 PM WEDNESDAY. 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...6 PM TUESDAY TO 3 PM WEDNESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 315 PM CST Mon Jan 5 2015 .SHORT TERM...(Tonight) ISSUED AT 313 PM CST MON JAN 5 2015 The 12z models continue to show a short duration, high-intensity snow event this evening. Light snow has already developed across our SW counties, which the HRRR shows will expand northward by 6 pm and intensify this evening. The surface low track is progged to go across IL on a line from Pittsfield to Effingham, which generally fits our current snowfall forecast coverage. One additional concern is trying to pinpoint the location of the traditional 60-80 mile wide band of heaviest snowfall. At this point, it looks like it will extend along and just north of the I-74 corridor. Satellite and radar images are confirming the development of a robust frontogenetical circulation upstream across NE SD, SW MN, and Iowa. Model analysis shows that to be in the 850-700 mb layer. The strongest axis of this F-gen circ is projected to advance across our northern counties this evening. Bufkit sounding analysis for sites along the I-74 corridor continues to indicate the co- location of the max omega, 80+% RH, and dendritic growth zone for several hours this evening. Those conditions will translate to the production of large, fluffy snowflakes. Snowfall rates in this axis will likely climb between 1-1.5" per hour. Additional small- scale bands of heavier snow could develop in areas farther south and north of the primary band, so we kept the snow totals on the higher side of advisory all the way through Lincoln to Mattoon, where a range of 2-5" is expected. A sharp southern edge remains indicated by most of the model suite, with locations south of Springfield and Mattoon likely seeing a dusting to 1 inch. In addition, after coordination with DVN, LOT, and IND, we decided to upgrade the I-74 corridor counties from Advisory to Warning due to the potential for more widespread 6-7" snowfall totals. The southeast winds this evening will not be much stronger that 10 mph, but the fluffy snow may be light enough for some minor drifting along roadways. Snowfall will rapidly diminish from west to east late this evening and after midnight, as the clipper races into southern Indiana/ Kentucky and weakens. Additional snow accums after midnight will be light, with the best chances of more than a half inch mainly east of Champaign to Paris. Most areas will just see some lingering flurries for a few hours after midnight. Low temps tonight will drop into the 5-10 range north, with around 20 from Flora to Lawrenceville. && .LONG TERM...(Tuesday through Monday) ISSUED AT 313 PM CST MON JAN 5 2015 The bitterly cold airmass will dominate the remainder of the forecast. Models are still on track with the intense cold that will follow tonight`s clipper. Tuesday will see skies begin to clear out from west to east during the afternoon, and W-NW winds increase. Blowing and drifting snow may develop as the fluffy snow gets pushed around, causing travel problems on north-south roads. On Wednesday, an unusually strong surface high, on the order of 1058 mb, will build southeast through the Dakotas, before settling into the Ohio Valley by early Thursday. The strong pressure contrast will result in northwest winds of 15-25 mph Tuesday night and Wednesday, with some gusts to over 30 mph. Lobe of -24C air at 850 mb will pivot through the Midwest on Wednesday. Highs on Wednesday likely to remain below zero across the northern CWA, with lows Wednesday night 10-15 below zero north of I-74. Wind chill warnings and advisories will be needed for late Tuesday night into Thursday morning, as most of the forecast area sees wind chills 15-25 below with lower than -25 across the north. Have decided to hold off on adding wind chill headlines to the mix, due to the winter storm expected tonight across much of the same area. The next clipper system is projected to remain across southern Canada on Thursday, dragging a cold front across northern IL Thursday night. At this point, we are keeping snow out of the forecast for Thur night. However, as the system becomes better defined in a couple days, we may need to add a mention of light snow for at least our northern counties. Behind that cold front we will see a reinforcing push of cold air, but not as cold as the mid-week airmass. We still expect very cold conditions as wind chills remain below zero on Friday morning and especially Saturday morning when -10F wind chills develop. For the weekend, we are still seeing phasing differences in the northern and southern jet branches. A couple of shortwaves could progress across IL during the weekend, but timing remains a question. There would be a period of light snow with any weak disturbances that move across the area. Some relief from the cold is projected for next Monday, as highs climb into the upper 20s and lower 30s. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 1150 AM CST MON JAN 5 2015 Not much of a shift in the forecast overall. Mid level clouds moving in just ahead of the Clipper system. Snow moving in this afternoon and spreading through the evening. Dropping fcst to IFR/LIFR with the heaviest of the snowfall. VV should be limited particularly in PIA, BMI and CMI, associated with the heaviest of the snowfall rates. Snowfall max generally between 00z and 06z, though moderate snowfall in scattered areas possible between 06z and 12z, though very small scale and not worth a mention just yet. Switching the winds to more northwesterly after the system moves out in the morning and breaking up the cigs mid morning...starting the trend, though confidence in the timing is low. && .ILX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING until 6 AM CST Tuesday FOR ILZ027>031-037- 038-045-046. WINTER WEATHER ADVISORY until 6 AM CST Tuesday FOR ILZ036- 041>044-053>057. && $$ SHORT TERM...HJS/Shimon LONG TERM...Shimon AVIATION...HJS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
214 PM MST MON JAN 5 2015 .SHORT TERM...(TONIGHT AND TUESDAY) ISSUED AT 213 PM MST MON JAN 5 2015 EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW NW FLOW EXTENDING FROM THE CANADIAN ROCKIES TO THE CENTRAL MISSISSIPPI RIVER VALLEY. A SHORTWAVE TROUGH IS CURRENTLY CENTERED OVER NORTH DAKOTA. AT THE SURFACE LEE TROUGH HAS DEVELOPED WITH WARMING TEMPERATURES ALONG FRONT RANGE AS A RESULT OF DOWNSLOPE IN THE CENTRAL ROCKIES. LOW PRESSURE EXTENDS ACROSS WESTERN KANSAS. THIS AFTERNOON...TEMPS HAVE STRUGGLED TO WARM AS A RESULT OF CLOUD COVER AND SHALLOW INVERSION OVER ESTABLISHED SNOW PACK. SOUTHERLY FLOW HAS MANAGED TO BRING WARMER TEMPS FROM FRONT RANGE TOWARDS EASTERN PLAINS OF COLORADO...HOWEVER THESE HAVE STRUGGLED TO ADVECT FURTHER EAST AS WEAKER FLOW HAS BEEN IN PLACE IN KS/NE. I WOULD STILL EXPECT TEMPS TO REACH ABOVE FREEZING AT LEAST IN THE WEST...BUT THERE MAY BE VERY LITTLE ADDITIONAL WARMING IN OUR EAST. TONIGHT-TUESDAY...COLD FRONT DROPS SOUTH OVER THE CWA TONIGHT AS SHORTWAVE TROUGH MOVES ACROSS NORTHERN PLAINS INTO NORTHERN MISSISSIPPI VALLEY. DEEP DRY AIR MASS WILL REMAIN IN PLACE...SO NOT EXPECTING ANY PRECIP. NAM/RAP SHOWING STRATUS/FOG DEVELOPING BEHIND THIS FRONT...HOWEVER MODEL SOUNDINGS CONTINUE TO INDICATE THIS SATURATED LAYER REMAINING VERY SHALLOW. I AM ALSO SKEPTICAL OF THE BL CONDITIONS ADVERTISED IN NAM AS ITS SNOW DEPTH IS SIGNIFICANTLY HIGHER THAN REALITY (SHOWING 5-12" ACROSS CWA WHEN IN REALITY IT AVERAGES 1-3"). BL CONDITIONS MAY BE OVERLY INFLUENCED BY THIS FIELD AND SINCE FOG/STRATUS NEVER MATERIALIZED LAST NIGHT I DECIDED TO HOLD OFF MENTION IN GRIDS. WARM FRONT LIFT NORTH TUESDAY AS LEE TROUGH REDEVELOPS. SAME ISSUES WITH WARMING TUESDAY AS TODAY AS CLOUDS SNOW PACK POSSIBLY LIMITING MIXING. NUDGED HIGHS TUESDAY TOWARD WHATS BEEN OBSERVED SO FAR TODAY. NOT A LOT OF CONFIDENCE IN THESE PERIOD WITH ANYTHING OTHER THAN A DRY FORECAST. .LONG TERM...(TUESDAY NIGHT THROUGH NEXT MONDAY) ISSUED AT 213 PM MST MON JAN 5 2015 SHORTWAVE TROUGH EMBEDDED IN NORTHWEST FLOW WILL BRING A CHANCE FOR VERY LIGHT SNOW TUESDAY NIGHT AND WEDNESDAY MORNING. SNOW ACCUMULATIONS WILL BE LESS THAN AN INCH. COLD ARCTIC AIR WILL SPILL IN BEHIND THE ASSOCIATED SURFACE FRONT WITH HIGH TEMPERATURES ON WEDNESDAY IN THE TEENS. TEMPERATURES WILL MODERATE ON THURSDAY WITH DOWNSLOPING SURFACE WINDS...BUT ANOTHER COLD FRONT WILL ARRIVE THURSDAY AFTERNOON BRINGING A CHANCE FOR LIGHT SNOW THURSDAY NIGHT AND FRIDAY MORNING. ACCUMULATIONS WILL AGAIN BE VERY LIGHT...LESS THAN AN INCH EXPECTED. TEMPERATURES WILL NOT BE QUITE AS COLD BEHIND THAT FRONT WITH HIGHS ON FRIDAY IN THE 20S. THE REMAINDER OF THE PERIOD WILL BE DRY WITH A ZONAL FLOW DEVELOPING ACROSS THE CONUS. HOWEVER...TEMPERATURES WILL CONTINUE TO BE BELOW NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1026 AM MST MON JAN 5 2015 VFR CONDITIONS SHOULD PREVAIL THROUGH AT LEAST 06Z AT BOTH KGLD AND KMCK TERMINALS. LOW CONFIDENCE IN FORECAST AFTER 06Z...AS NAM/RAP SHOWING LOW VIS DEVELOPING LATE TONIGHT THROUGH THE MIDDLE OF TUESDAY MORNING BEHIND COLD FRONT. I COULD SEE SOME MOISTURE POOLING WITH LIGHT NORTHERLY WINDS BEHIND THE FRONT...HOWEVER MODEL SOUNDINGS APPEAR VERY SHALLOW WITH THIS MOIST LAYER...AND MODELS COULD BE OVERLY INFLUENCED BY SNOW PACK. GFS MAY HAVE BETTER HANDLE AND SHOWS VFR PREVAILING. FOR NOW I KEPT VFR IN FORECAST AND ONLY INTRODUCED 6SM BR GROUP FOR 9-16Z PERIODS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...024 AVIATION...DR
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1203 PM CST MON JAN 5 2015 .UPDATE... ISSUED AT 1029 AM CST MON JAN 5 2015 THE PREVIOUS FORECAST LOOKED PRETTY GOOD AND ONLY MINOR CHANGES WERE NEEDED. LOADED STRAIGHT RAP HOURLY POPS THROUGH THIS EVENING...WHICH ALLOWED FOR BETTER TIMING AND A MORE BINARY LOOK TO THE POP GRIDS AS CONFIDENCE CONTINUES TO INCREASE. AMOUNTS STILL LOOK TO BE IN THE 6-8 INCH RANGE IN MARTIN COUNTY WITH AMOUNTS TAPERING OFF NORTH AND EAST OF HERE. MAY NOT SEE MUCH MORE THAN VERY LIGHT SNOW OR FLURRIES NORTH OF I-94 WHERE THE COLUMN WILL BE COLDER THAN THE DENDRITIC GROWTH ZONE LEAVING ONLY NEEDLES FOR FLAKES. NO CHANGES TO THE HEADLINES ARE NEEDED ATTM. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 329 AM CST MON JAN 5 2015 SFC ANALYSIS THIS MRNG SHOWS HIGH PRES CENTERED OVER THE CENTRAL CONUS...EXTENDING MORE N-S THAN E-W AND KEEPING MOCLR CONDS OVER THE UPR MISS RIVER VALLEY WHILE ALSO KEEPING WLY WINDS IN PLACE. TEMPS IN THE -10 TO -15 DEGREE RANGE WITH WINDS IN THE 8-15MPH RANGE ARE EASILY CREATING WIND CHILLS IN THE -25 TO -40 DEG F RANGE SO WILL MAINTAIN THE WIND CHILL WARNINGS AND ADVISORIES AS THEY ARE CURRENTLY DELINEATED...LASTING THRU 16Z AT WHICH TIME THERE IS EXPECTED TO BE ENOUGH IMPROVEMENT IN WINDS AND TEMPS TO SEE WIND CHILLS INCREASE TO -25 DEG F OR HIGHER. THE CONCERN THEN TURNS TO THE QUICK-HITTING CLIPPER SYSTEM THIS AFTN THRU THIS EVE. MODELS HAVE AGAIN TRENDED EVER-SO-SLIGHTLY FURTHER S AND LESS ON QPF. THE FOCUS STILL IS ON EXTREME SWRN PORTIONS OF THE CWFA FOR POTENTIALLY HITTING 6+ INCHES OF SNOW...BUT THERE DOES LOOK TO BE A TIGHT GRADIENT NEAR/OVER THE MINNESOTA RIVER. THE NAM/SREF ARE STILL THE NORTHERNMOST OUTLIERS WHILE CONSENSUS AMONG THE GFS/EC/GEM MAINTAIN OR EVEN PUSH S SLIGHTLY THE MAIN SWATH OF -SN. AS SUCH...HAVE OPTED TO KEEP THE WARNING AS-IS FOR THIS MRNG. AS FOR THE ADVY...THE TIGHT GRADIENT AND SWD SHIFT MAY MAKE IT DIFFICULT TO HIT 3 INCHES FOR RENVILLE THRU RICE COUNTIES. THAT SAID...THERE LOOKS TO BE MORE OF A WNW- ESE ORIENTATION IN THE BAND OF SNOW RATHER THAN A NW-SE...AND THIS WOULD FAVOR SLIGHTLY HIGHER AMOUNTS IN LAC QUI PARLE COUNTY TO JUST OVER ADVISORY CRITERIA. THEREFORE...HAVE CONVERTED ALL COUNTIES IN THE WINTER STORM WATCH TO A WINTER WEATHER ADVISORY AND ALSO ADDED IN LAC QUI PARLE COUNTY. -SN LOOKS TO MOVE IN MID- TO-LATE AFTN AND THE HEAVIEST DURG THE EVENING HOURS BEFORE TAPERING OFF DURG THE EARLY MRNG HRS TUE. WINDS LOOK TO DROP OFF ENOUGH SUCH THAT BLOWING SNOW WILL NOT BE A CONCERN...SO HAVE HELD OFF ANY MENTION OF BLOWING/DRIFTING SNOW. ONCE PAST THE FRIGID WIND CHILLS OF THIS MRNG...SLIGHT WAA ASSOCIATED WITH THIS INCOMING CLIPPER SYSTEM WILL ALLOW HIGHS TDA TO BE A COUPLE TO A FEW DEGREES HIGHER THAN WHAT WAS RECORDED YDA. SIMILARLY...THE CLOUD COVER TNGT WITH THE PASSING SYSTEM WILL KEEP MIN TEMPS UP SLIGHTLY FROM THIS MRNG...GENERALLY IN THE -5 TO -10 DEG F RANGE FOR EARLY TUE MRNG. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 329 AM CST MON JAN 5 2015 THE MAIN STORIES OF THE LONG TERM PERIOD ARE THE VERY COLD TEMPERATURES/WIND CHILLS AND THE POTENTIAL FOR BLOWING SNOW. LITTLE PRECIPITATION EXPECTED THIS PERIOD...JUST A CHANCE OF LIGHT SNOW ON THURSDAY. BY TOMORROW MORNING...THE STORM WILL BE LONG GONE AND INCREASING NORTHWEST WINDS WILL PUSH INTO THE REGION AS A STRENGTHENING SURFACE HIGH IN SOUTHWESTERN CANADA BEGINS PUSHING SOUTHEAST TOWARD OUR AREA. ANOTHER CORE OF ARCTIC AIR WILL PUSH SOUTH TOWARD US ON TUESDAY AND HIGH TEMPERATURES WILL RECOVER LITTLE UNDER THE STRONG NORTHWEST FLOW. SINGLE DIGIT HIGHS ARE LIKELY WITH WIND CHILL VALUES IN THE -20S. THE STRONG SURFACE HIGH /MSLP VALUES OF 1056-1060MB/ WILL DROP INTO THE WESTERN DAKOTAS TUESDAY NIGHT. WITH IT...THE CORE OF THE COLD WILL ROTATE SOUTHWARD AND EXTEND FROM THE GREAT LAKES THROUGH MINNESOTA. WITH THE APPROACHING AND STRENGTHENING HIGH...WIND SPEEDS LOOK TO MAXIMIZE DURING THE NIGHT. LOW TEMPERATURES DURING THE NIGHT SHOULD HAVE NO PROBLEM FALLING INTO THE -10S EVERYWHERE. WITH THESE TEMPERATURES AND THE WINDS INCREASING TO GENERALLY 15-25MPH...DANGEROUSLY COLD WIND CHILL VALUES IN THE -30 TO -40 RANGE ARE EXPECTED ACROSS THE FORECAST AREA. WINDS WILL WEAKEN DURING THE DAY WEDNESDAY AS THE GRADIENT WEAKENS...AND WIND CHILL VALUES WILL IMPROVE. THE SURFACE HIGH WILL DIVE SOUTH OF US AND PUSH EAST WEDNESDAY NIGHT. ON WEDNESDAY NIGHT...A SUBTLE SHORTWAVE WHICH STOOD OUT BEST AT 850MB /AND ASSOCIATED WEAK SURFACE LOW/...WILL MOVE EAST ACROSS THE DAKOTAS TOWARD MINNESOTA. DECENT LOW LEVEL LIFT WILL BE SEEN FOR A PERIOD FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING DUE TO WARM AIR ADVECTION FROM THE SOUTHWEST. BOTH THE GFS AND EC INDICATE THIS LIFT MAY BE ENOUGH TO SQUEEZE OUT SOME LIGHT SNOW. INTRODUCED SLIGHT CHANCE POPS ACROSS WESTERN MN LATE WEDNESDAY NIGHT. SATURATION LOOKS TO BE MORE OF A SURE BET FARTHER EAST DURING THE DAY THURSDAY. POPS WERE INCREASED TO CHANCE CATEGORY ACROSS THE EASTERN HALF OF THE FA GIVEN DECENT AGREEMENT BETWEEN THE GFS/EC. AN ARCTIC FRONT WILL FOLLOW THIS WAVE AND WEAK SURFACE LOW THURSDAY...AND ANOTHER BOUT OF 850MB TEMPS COLDER THAN -20C WILL ADVECT SOUTHWARD THROUGH OUR AREA BY LATE THURSDAY NIGHT. THIS SURGE WILL BE FLEETING THOUGH...THE JET WILL LIFT NORTH OF US BY SATURDAY AND SOUTHERLY WINDS WILL ENSUE AS WE`LL BE ON THE BACKSIDE OF A SURFACE HIGH MOVING TOWARD THE SOUTHERN GREAT LAKES. HIGH TEMPERATURES WILL MODERATE BUT REMAIN BELOW NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1142 AM CST MON JAN 5 2015 SNOW OVER THE DAKOTAS WILL SLIDE SOUTHEAST...WITH THE HEAVIEST REMAINING ALONG AND SOUTH OF THE MN RIVER IN SOUTHWESTERN MN. LIFR CONDITIONS ARE POSSIBLE LATE THIS AFTERNOON AND EARLY THIS EVENING AT RWF. TO THE NORTH AND EAST...MAINLY MVFR CONDITIONS ARE EXPECTED ALTHOUGH A FEW IFR BURSTS ARE POSSIBLE FROM AXN TO MSP AND EAU. CONFIDENCE IN TIMING AND INTENSITY IS FAIRLY HIGH. WINDS WILL BACK SOUTHEAST LATER TODAY...THEN BECOME WEST NORTHWEST BEHIND THE SYSTEM TONIGHT. KMSP...BIGGEST UNCERTAINTY IN THIS FORECAST IS THE PRECISE BEGINNING AND ENDING TIMES OF THE SNOW...AND EVEN THAT IS FAIRLY CERTAIN. THINK THE SNOW WILL START BETWEEN 23-00Z AND END AROUND MID EVENING. MAINLY MVFR CONDITIONS ARE EXPECTED. SNOW ACCUMULATIONS WILL BE ABOUT AN INCH. /OUTLOOK FOR KMSP/ TUE...VFR. WINDS NW 10-20 KTS. WED...VFR. WINDS W 10-15 KTS. THU...VFR. WINDS SW 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ054- 064-065-067-073>077-083>085-093. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR MNZ082-091- 092. WI...NONE. && $$ UPDATE...BORGHOFF SHORT TERM...JPC LONG TERM...SPD AVIATION...BORGHOFF
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1030 AM CST MON JAN 5 2015 .UPDATE... ISSUED AT 1029 AM CST MON JAN 5 2015 THE PREVIOUS FORECAST LOOKED PRETTY GOOD AND ONLY MINOR CHANGES WERE NEEDED. LOADED STRAIGHT RAP HOURLY POPS THROUGH THIS EVENING...WHICH ALLOWED FOR BETTER TIMING AND A MORE BINARY LOOK TO THE POP GRIDS AS CONFIDENCE CONTINUES TO INCREASE. AMOUNTS STILL LOOK TO BE IN THE 6-8 INCH RANGE IN MARTIN COUNTY WITH AMOUNTS TAPERING OFF NORTH AND EAST OF HERE. MAY NOT SEE MUCH MORE THAN VERY LIGHT SNOW OR FLURRIES NORTH OF I-94 WHERE THE COLUMN WILL BE COLDER THAN THE DENDRITIC GROWTH ZONE LEAVING ONLY NEEDLES FOR FLAKES. NO CHANGES TO THE HEADLINES ARE NEEDED ATTM. && .UPDATE... ISSUED AT 653 AM CST MON JAN 5 2015 UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW...AND TO DOWNGRADE THE WIND CHILL WARNING TO AN ADVISORY FOR THE NORTHERN TIER OF COUNTIES. WINDS HAVE JUST ABOUT TOPPED OUT FOR THE MORNING...AND HAVE EVEN DIMINISHED BEFORE PREVIOUSLY FORECASTED SPEEDS...WHILE TEMPERATURES ARE NOT EXPECTED TO DROP ANY FURTHER...OR A DEGREE OR SO AT BEST. THEREFORE...WITH MAYBE AN ISOLATED -35 OR LOWER READING POSSIBLE AND NOT MORE WIDESPREAD SUCH VALUES EXPECTED...HAVE OPTED TO DROP THE WARNING IN FAVOR OF AN ADVISORY FOR THE DURATION TO 16Z. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 329 AM CST MON JAN 5 2015 SFC ANALYSIS THIS MRNG SHOWS HIGH PRES CENTERED OVER THE CENTRAL CONUS...EXTENDING MORE N-S THAN E-W AND KEEPING MOCLR CONDS OVER THE UPR MISS RIVER VALLEY WHILE ALSO KEEPING WLY WINDS IN PLACE. TEMPS IN THE -10 TO -15 DEGREE RANGE WITH WINDS IN THE 8-15MPH RANGE ARE EASILY CREATING WIND CHILLS IN THE -25 TO -40 DEG F RANGE SO WILL MAINTAIN THE WIND CHILL WARNINGS AND ADVISORIES AS THEY ARE CURRENTLY DELINEATED...LASTING THRU 16Z AT WHICH TIME THERE IS EXPECTED TO BE ENOUGH IMPROVEMENT IN WINDS AND TEMPS TO SEE WIND CHILLS INCREASE TO -25 DEG F OR HIGHER. THE CONCERN THEN TURNS TO THE QUICK-HITTING CLIPPER SYSTEM THIS AFTN THRU THIS EVE. MODELS HAVE AGAIN TRENDED EVER-SO-SLIGHTLY FURTHER S AND LESS ON QPF. THE FOCUS STILL IS ON EXTREME SWRN PORTIONS OF THE CWFA FOR POTENTIALLY HITTING 6+ INCHES OF SNOW...BUT THERE DOES LOOK TO BE A TIGHT GRADIENT NEAR/OVER THE MINNESOTA RIVER. THE NAM/SREF ARE STILL THE NORTHERNMOST OUTLIERS WHILE CONSENSUS AMONG THE GFS/EC/GEM MAINTAIN OR EVEN PUSH S SLIGHTLY THE MAIN SWATH OF -SN. AS SUCH...HAVE OPTED TO KEEP THE WARNING AS-IS FOR THIS MRNG. AS FOR THE ADVY...THE TIGHT GRADIENT AND SWD SHIFT MAY MAKE IT DIFFICULT TO HIT 3 INCHES FOR RENVILLE THRU RICE COUNTIES. THAT SAID...THERE LOOKS TO BE MORE OF A WNW- ESE ORIENTATION IN THE BAND OF SNOW RATHER THAN A NW-SE...AND THIS WOULD FAVOR SLIGHTLY HIGHER AMOUNTS IN LAC QUI PARLE COUNTY TO JUST OVER ADVISORY CRITERIA. THEREFORE...HAVE CONVERTED ALL COUNTIES IN THE WINTER STORM WATCH TO A WINTER WEATHER ADVISORY AND ALSO ADDED IN LAC QUI PARLE COUNTY. -SN LOOKS TO MOVE IN MID- TO-LATE AFTN AND THE HEAVIEST DURG THE EVENING HOURS BEFORE TAPERING OFF DURG THE EARLY MRNG HRS TUE. WINDS LOOK TO DROP OFF ENOUGH SUCH THAT BLOWING SNOW WILL NOT BE A CONCERN...SO HAVE HELD OFF ANY MENTION OF BLOWING/DRIFTING SNOW. ONCE PAST THE FRIGID WIND CHILLS OF THIS MRNG...SLIGHT WAA ASSOCIATED WITH THIS INCOMING CLIPPER SYSTEM WILL ALLOW HIGHS TDA TO BE A COUPLE TO A FEW DEGREES HIGHER THAN WHAT WAS RECORDED YDA. SIMILARLY...THE CLOUD COVER TNGT WITH THE PASSING SYSTEM WILL KEEP MIN TEMPS UP SLIGHTLY FROM THIS MRNG...GENERALLY IN THE -5 TO -10 DEG F RANGE FOR EARLY TUE MRNG. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 329 AM CST MON JAN 5 2015 THE MAIN STORIES OF THE LONG TERM PERIOD ARE THE VERY COLD TEMPERATURES/WIND CHILLS AND THE POTENTIAL FOR BLOWING SNOW. LITTLE PRECIPITATION EXPECTED THIS PERIOD...JUST A CHANCE OF LIGHT SNOW ON THURSDAY. BY TOMORROW MORNING...THE STORM WILL BE LONG GONE AND INCREASING NORTHWEST WINDS WILL PUSH INTO THE REGION AS A STRENGTHENING SURFACE HIGH IN SOUTHWESTERN CANADA BEGINS PUSHING SOUTHEAST TOWARD OUR AREA. ANOTHER CORE OF ARCTIC AIR WILL PUSH SOUTH TOWARD US ON TUESDAY AND HIGH TEMPERATURES WILL RECOVER LITTLE UNDER THE STRONG NORTHWEST FLOW. SINGLE DIGIT HIGHS ARE LIKELY WITH WIND CHILL VALUES IN THE -20S. THE STRONG SURFACE HIGH /MSLP VALUES OF 1056-1060MB/ WILL DROP INTO THE WESTERN DAKOTAS TUESDAY NIGHT. WITH IT...THE CORE OF THE COLD WILL ROTATE SOUTHWARD AND EXTEND FROM THE GREAT LAKES THROUGH MINNESOTA. WITH THE APPROACHING AND STRENGTHENING HIGH...WIND SPEEDS LOOK TO MAXIMIZE DURING THE NIGHT. LOW TEMPERATURES DURING THE NIGHT SHOULD HAVE NO PROBLEM FALLING INTO THE -10S EVERYWHERE. WITH THESE TEMPERATURES AND THE WINDS INCREASING TO GENERALLY 15-25MPH...DANGEROUSLY COLD WIND CHILL VALUES IN THE -30 TO -40 RANGE ARE EXPECTED ACROSS THE FORECAST AREA. WINDS WILL WEAKEN DURING THE DAY WEDNESDAY AS THE GRADIENT WEAKENS...AND WIND CHILL VALUES WILL IMPROVE. THE SURFACE HIGH WILL DIVE SOUTH OF US AND PUSH EAST WEDNESDAY NIGHT. ON WEDNESDAY NIGHT...A SUBTLE SHORTWAVE WHICH STOOD OUT BEST AT 850MB /AND ASSOCIATED WEAK SURFACE LOW/...WILL MOVE EAST ACROSS THE DAKOTAS TOWARD MINNESOTA. DECENT LOW LEVEL LIFT WILL BE SEEN FOR A PERIOD FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING DUE TO WARM AIR ADVECTION FROM THE SOUTHWEST. BOTH THE GFS AND EC INDICATE THIS LIFT MAY BE ENOUGH TO SQUEEZE OUT SOME LIGHT SNOW. INTRODUCED SLIGHT CHANCE POPS ACROSS WESTERN MN LATE WEDNESDAY NIGHT. SATURATION LOOKS TO BE MORE OF A SURE BET FARTHER EAST DURING THE DAY THURSDAY. POPS WERE INCREASED TO CHANCE CATEGORY ACROSS THE EASTERN HALF OF THE FA GIVEN DECENT AGREEMENT BETWEEN THE GFS/EC. AN ARCTIC FRONT WILL FOLLOW THIS WAVE AND WEAK SURFACE LOW THURSDAY...AND ANOTHER BOUT OF 850MB TEMPS COLDER THAN -20C WILL ADVECT SOUTHWARD THROUGH OUR AREA BY LATE THURSDAY NIGHT. THIS SURGE WILL BE FLEETING THOUGH...THE JET WILL LIFT NORTH OF US BY SATURDAY AND SOUTHERLY WINDS WILL ENSUE AS WE`LL BE ON THE BACKSIDE OF A SURFACE HIGH MOVING TOWARD THE SOUTHERN GREAT LAKES. HIGH TEMPERATURES WILL MODERATE BUT REMAIN BELOW NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 653 AM CST MON JAN 5 2015 SKC CONDS THIS MRNG WILL GRADUALLY BE REPLACED BY HIGH CLOUDS THAT WILL LOWER THRU THE DAY AS A CLIPPER LOW PRES SYSTEM ARRIVES FROM THE SW. SYSTEM WILL TRACK TO THE S...SLIGHTLY FURTHER THEN PREV FCST...SHUNTING THE HEAVIER SNOWFALL TO THE IOWA BORDER AND SWRN MN. THUS...THE TERMINAL THAT LOOKS TO BE MOST AFFECTED WILL BE KRWF WITH LESSER EFFECTS IN KMSP-KEAU AND NORTHWARD. BECAUSE OF THE RELATIVE SPEED OF THE SYSTEM AND STRONG LIFT/DYNAMICS ASSOCIATED WITH IT...HAVE BUILT IN A WINDOW OF IFR VSBY SNOW AT ALL SITES. NOT LOOKING FOR CEILINGS TO DROP TO IFR WITH THE SNOWFALL. CONDS QUICKLY IMPROVE LATE EVE THRU EARLY MRNG HRS BACK TO VFR WITH MID-HIGH CLOUDS BY DAYBREAK TMRW MRNG. WINDS WILL BE SHIFTING THROUGHOUT THE NEXT 24 HRS...BUT WITH SPEEDS GENERALLY AOB 10 KT. KMSP...VFR CONDS XPCTD THRU THIS AFTN THEN CONDS QUICKLY DETERIORATE THIS EVE WITH THE ONSET OF -SN. THE SPEED OF THE SYSTEM LOOK TO ALLOW VSBY TO DROP TO MVFR RIGHT OFF AND REMAIN THERE THRU THE BULK OF THE EVENING. THERE IS THE POTENTIAL FOR A HEAVIER BURST OR TWO...BRINGING VSBY DOWN TO IFR...BUT AM NOT EXPECTING RATES OF 1 INCH/HOUR. /OUTLOOK FOR KMSP/ TUE...VFR. WINDS NW 10-20 KTS. WED...VFR. WINDS W 10-15 KTS. THU...VFR. WINDS SW 10-15 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ054- 064-065-067-073>077-083>085-093. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR MNZ082-091- 092. WI...NONE. && $$ UPDATE...BORGHOFF SHORT TERM...JPC LONG TERM...SPD AVIATION...JPC
AREA FORECAST DISCUSSION
NWS BILLINGS MT
324 PM MST MON JAN 5 2015 .SHORT TERM...VALID FOR TUE AND WED... WE HAVE MADE SOME RELATIVELY SIGNIFICANT CHANGES WITH THE FORECAST ISSUANCE THIS AFTERNOON....AS THE MAIN AXIS OF SNOWFALL DURING THE NEXT 36 HOURS LOOKS TO BE A BIT NORTHEAST OF EARLIER EXPECTATIONS. WE BELIEVE THAT ADDITIONAL SNOWFALL BETWEEN 5 PM MST /00 UTC/ THIS EVENING AND 5 AM /12 UTC/ WEDNESDAY MORNING WILL BE 3 TO LOCALLY 6 INCHES OVER PARTS OF THE AREA...CENTERED ALONG A LINE FROM ROUNDUP TO HYSHAM...FORSYTH AND COLSTRIP. AS OF 22 UTC...STRONG SURFACE PRESSURE RISES ON THE ORDER OF 6 MB/ 3 HOURS ARE DROPPING THROUGH SOUTHEASTERN MT WITH WIND GUSTS OF 30 TO 45 MPH COMMON...CAUSING SOME BLOWING AND DRIFTING SNOW. WE FIND IT INTERESTING THAT IN SPITE OF THE ARCTIC FRONTAL PASSAGE LOCALLY AT BILLINGS A FEW HOURS AGO...TEMPERATURES ARE ONLY SLOWLY FALLING INTO THE LOWER AND MID 20S F. THIS MAY BE REFLECTIVE OF A SOMEWHAT SHALLOW WESTERN EDGE OF THE FRONTAL ZONE...WHICH WOULD CONFIRM THE IDEA HELD IN THE 12 UTC GUIDANCE FOR THE FRONT TO NOT REACH AS FAR WEST AS THE FOOTHILLS OR LIVINGSTON AS PREVIOUSLY EXPECTED. WE SAW GREAT AGREEMENT IN THE 12 UTC GFS AND ECMWF MODELS FOR THE FRONTAL ZONE TO STAY OFF THE FOOTHILLS...WITH FORCING THIS EVENING LOCATED AROUND BILLINGS BEFORE IT ACTUALLY LIFTS BACK NORTHEASTWARD BEYOND 06 UTC. WARM AIR ADVECTION ALOFT WILL THEN FOCUS FROM ROUNDUP OVER TO HYSHAM...MILES CITY AND BROADUS LATE TONIGHT INTO EARLY TUESDAY FOR LIGHT SNOW PRODUCTION THERE. THE GUIDANCE THEN AGREES THAT THE FRONTAL ZONE WILL SLOSH BACK SOUTHWEST DURING THE DAY SO THAT SNOW PICKS UP AGAIN IN PLACES LIKE BILLINGS TUESDAY AFTERNOON AND RIGHT INTO TUESDAY EVENING. HOWEVER...WITH THE MORE SHALLOW FRONTAL ZONE ALOFT THE DENDRITIC GROWTH LAYER IS NOT NEARLY AS EFFICIENT ON ITS WEST SIDE /OVER BILLINGS/ TUESDAY AFTERNOON AND EVENING AS PERHAPS EARLIER EXPECTED. SO...TAKING THE 12 UTC MULTI-MODEL CONSENSUS QPF INTO ACCOUNT WITH A MIX OF COBB AND ROEBBER METHOD SNOW RATIOS YIELDED AN ADDITIONAL 3 TO LOCALLY 6 INCHES OF SNOW...THE LATTER MOST LIKELY AROUND THAT HYSHAM AREA. THE HRRR AND TO A LESSER EXTENT THE 12 UTC NCEP WRF/S /ARW AND NMM/ PRODUCE LITTLE MOISTURE FROM NORTHERN PARK COUNTY TO LIVINGSTON...NYE OR RED LODGE TONIGHT. RECENT RADAR AND WEB CAMERA IMAGES DO SHOW SOME SNOW AT RED LODGE THOUGH SO WE HAVE DECIDED TO KEEP THE ADVISORY GOING IN THE FOOTHILLS FOR A WHILE...BUT DROPPED THE HEADLINES FOR NORTHERN PARK COUNTY AND LIVINGSTON. WE SWITCHED WARNINGS BACK TO ADVISORIES FOR YELLOWSTONE...MUSSELSHELL AND EVEN TREASURE COUNTY TOO SINCE THEY WERE MAINLY ISSUED FOR THE SNOWFALL WHICH COULD HAVE BEEN HEAVIER IN PLACES LIKE BILLINGS TODAY...WITH A COUPLE INCHES OVER THE NEXT 36 HOURS NOT ENOUGH TO KEEP WARNINGS GOING...ESPECIALLY ONCE WINDS SUBSIDE THIS EVENING. WE LEFT UP THE WARNINGS FOR BIG HORN AND SOUTHERN ROSEBUD COUNTY FOR NOW BASED ON RECENT RADAR TRENDS...BUT THE EVENING OR MIDNIGHT SHIFTS SHOULD BE ABLE TO REVERT THEM OVER TO ADVISORIES AT SOME POINT TOO ONCE THIS AFTERNOON/S SNOW AND WINDS SETTLE DOWN. WE NEED TO STRESS THAT THERE ARE STILL NUANCES TO WORK OUT IN THIS SITUATION AND SO ADDITIONAL FORECAST ADJUSTMENTS ARE LIKELY IN THE NEXT FEW FORECAST SHIFTS. FOR EXAMPLE...AFTERNOON HRRR SIMULATIONS SHOW SOME FREEZING DRIZZLE OR VERY LIGHT FREEZING RAIN THREAT NEAR THE WESTERN SIDE OF THE RETREATING ARCTIC FRONT LATE TONIGHT WHICH WOULD INCLUDE THE BILLINGS AREA. CONFIDENCE IS NOT HIGH ENOUGH FOR US TO INCLUDE THAT IN THE FORECAST...BUT IT WILL BEAR MONITORING. BY WEDNESDAY...THE SNOW MACHINE WILL HAVE SHUT DOWN AND WE WILL BE IN A FAVORABLE PATTERN TO WARM UP SOMEWHAT...ALBEIT REGULATED BY A RELATIVELY DEEP SNOW PACK IN MANY AREAS. SCHULTZ .LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON... EXTENDED MODELS OVERALL ARE IN FAIRLY GOOD AGREEMENT. AN UNSETTLED NORTHWEST FLOW ALOFT WILL CONTINUE THURSDAY AS ANOTHER DISTURBANCE MOVES ACROSS THE FORECAST AREA. THIS WILL BRING ANOTHER SHOT OF ARCTIC AIR ALONG WITH A CHANCE FOR LIGHT SNOW. THE RIDGE AXIS THAT HAS BEEN OVER THE PACIFIC NORTHWEST COAST RESULTING IN THE NORTHWEST FLOW ALOFT WE HAVE EXPERIENCED FOR QUITE A FEW DAYS NOW WILL BEGIN TO SHIFT EAST FRIDAY INTO NEXT WEEKEND ALLOWING FOR THE VERY COLD ARCTIC AIR TO SLOWLY RETREAT. ANOTHER DISTURBANCE LOOKS TO CROSS THE AREA SATURDAY RESULTING IN ANOTHER CHANCE FOR LIGHT SNOW. HOWEVER...AT THIS TIME...BOTH DISTURBANCES ARE NOT NEARLY AS STRONG NOR DYNAMIC AND MOISTURE LADEN HAS HAS BEEN THE CASE THE PAST SEVERAL DAYS. MODELS SHOW THE ARCTIC BOUNDARY WOBBLING BACK AND FORTH ACROSS THE CENTRAL PORTIONS OF OUR FORECAST AREA THURSDAY THROUGH SATURDAY RESULTING IN LARGE TEMPERATURE DIFFERENCES BETWEEN OUR EASTERN AND WESTERN LOCATIONS. MODELS THEN SHOW THE ARCTIC PULLING OUT OF THE AREA SUNDAY INTO MONDAY. TEMPERATURES WILL STILL BE A GOOD 10 DEGREES BELOW NORMAL SUNDAY INTO MONDAY BUT NOT NEARLY AS COLD AS THE PAST SEVERAL DAYS. HOOLEY && .AVIATION... AREAS OF LIGHT TO MODERATE SNOW WILL CONTINUE ACROSS THE FORECAST AREA FOR THE REMAINDER OF THIS AFTERNOON AND THROUGH THE OVERNIGHT HOURS. THE BEST LOCATIONS FOR THE HEAVIER SNOW WILL BE ABOUT 40 MILES EAST AND WEST OF A KSHR-KBIL-ROUNDUP LINE. MVFR TO IFR CONDITIONS WILL CONTINUE TO PREVAIL THROUGH TONIGHT WITH AREAS OF LIFR IN THE HEAVIER SNOW BANDS. THE MOUNTAINS WILL BE OBSCURED WELL INTO THE DAY TUESDAY. HOOLEY && .PRELIMINARY POINT TEMP/POPS... TUE WED THU FRI SAT SUN MON ----------------------------------------------------------- BIL 012/017 002/026 020/025 000/013 008/021 012/026 011/026 +7/S 71/E 02/J 21/B 22/J 21/B 11/B LVM 028/039 011/044 026/034 011/028 021/036 021/035 019/032 42/S 21/N 01/B 22/J 22/J 21/B 11/B HDN 010/017 002/025 016/026 905/016 004/022 004/025 005/025 +9/S 71/E 02/J 11/B 22/J 21/B 11/U MLS 904/010 911/018 012/018 910/009 905/013 903/021 000/021 59/S 41/E 12/J 11/B 21/B 11/B 10/B 4BQ 006/014 902/024 017/024 905/011 004/020 003/021 005/023 78/S 51/E 02/J 11/B 11/B 11/B 10/U BHK 908/008 914/014 010/018 909/004 904/012 902/016 000/020 16/S 20/B 12/J 10/B 11/B 11/B 10/B SHR 011/027 005/031 022/031 901/019 012/029 010/028 010/027 96/S 61/B 02/J 12/J 12/J 21/B 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST WEDNESDAY FOR ZONES 28>37-39-41-42. WINTER STORM WARNING IN EFFECT UNTIL 6 AM MST WEDNESDAY FOR ZONES 38-57-58-63-67-68. WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST TUESDAY FOR ZONES 56-66. WY...WINTER STORM WARNING IN EFFECT UNTIL 6 AM MST WEDNESDAY FOR ZONE 98. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
1106 AM MST MON JAN 5 2015 .UPDATE... WE CANCELLED THE HIGH WIND WARNING FOR LIVINGSTON AND NYE NOW WITH PEAK GUSTS ONLY NEAR 50 MPH AS OF 1030 AM MST. WE ALSO TWEAKED THE FORECAST HIGHS AND HOURLY TEMPERATURES TODAY AS TEMPERATURES AS OF 1045 AM MST HAVE RISEN WELL INTO THE MID 30S F EVEN IN BILLINGS IN ADVANCE OF THE ARCTIC FRONT. THAT ARCTIC FRONT JUST SURGED THROUGH JUDITH GAP RECENTLY AND WILL CONTINUE BLASTING SOUTH OVER THE NEXT SEVERAL HOURS. WE STILL EXPECT SNOW TO FILL BACK IN ONCE THE FRONT PASSES BILLINGS BY MID TO LATE AFTERNOON...BUT HOW MUCH SNOW FALLS IS ALSO STILL IN SOME QUESTION. WE WILL CONTINUE TO MONITOR TRENDS AND INCOMING MODEL DATA...WITH SOME ADDITIONAL CHANGES LIKELY WITH THE AFTERNOON FORECAST RELEASE OVER THOSE MENTIONED BELOW. SCHULTZ PREVIOUS FORECAST UPDATE...ISSUED AT 910 AM MST MON JAN 5 2015... THE MAIN FORECAST CHANGE THIS MORNING WAS TO LOWER SNOW TOTALS FOR TODAY OVER SOUTH CENTRAL MT...ESPECIALLY AROUND BILLINGS. THE LOW- LEVEL DOWNSLOPE FLOW ON THE SOUTH SIDE OF A SURFACE LOW LOCATED IN CENTRAL MT NEAR LEWISTOWN AS OF 16 UTC IS INHIBITING SNOWFALL THUS FAR THIS MORNING...AND THIS SITUATION WILL NOT CHANGE MUCH THROUGH THE MID TO LATE AFTERNOON WHEN THE ARCTIC FRONT RUSHES SOUTH...AND THE WINDS SWITCH BACK AROUND THE THE NORTHEAST IN BILLINGS. RECENT HIGH-RESOLUTION MODEL GUIDANCE SUGGESTS THAT MIGHT NOT OCCUR UNTIL VERY LATE AFTERNOON AND IN SOME OF THOSE SIMULATIONS NOT UNTIL THE EARLY EVENING HOURS. SO...WE CUT BACK ON SNOWFALL TOTALS TODAY FOR THE CITY AND SURROUNDING AREAS. THE ARCTIC FRONT JUST SURGED SOUTH THROUGH GREAT FALLS AT 9 AM...WHICH TYPICALLY MEANS IT COULD REACH BILLINGS BY 3 PM WITH SNOW THEN PICKING UP AFTER THAT TIME. WE ARE STILL CARRYING ABOUT 2 INCHES TOTAL FOR TODAY IN BILLINGS...BUT IT LOOKS LIKE IF WE GET THAT MUCH IT WILL BE MAINLY IN THE AFTERNOON. IN CONTRAST...SNOW IS FALLING LIKE EXPECTED IN SOUTHEASTERN MT AND VISIBILITY IS REDUCED TO 1/2SM IN MILES CITY AND BAKER AT THE MID- MORNING HOUR. WE STILL EXPECT 3 TO 6 INCHES OF SNOW IN TOTAL TODAY OVER SOUTHEASTERN MT. WE ARE CHOOSING TO LEAVE THE HIGH WIND WARNING UP AT LIVINGSTON AT THIS POINT GIVEN TRAVEL IMPACTS THERE...EVEN THOUGH WINDS ARE THUS FAR NOT NOT AS STRONG AS EXPECTED. WE WILL REVISIT THAT DURING THE LATE MORNING HOURS...ALONG WITH THE REST OF THE FORECAST FOR TODAY AND INTO TONIGHT...WHICH IS A VERY DIFFICULT ONE WHICH MAY REQUIRE FURTHER ADJUSTMENTS. SCHULTZ && .SHORT TERM...VALID FOR TDY AND TUE... VERY COMPLEX AND DYNAMIC WEATHER PATTERN TODAY...AND ONE THAT WILL BE VERY DIFFICULT TO PINPOINT EXACT RESULTS...EVEN THIS CLOSE IN TIME. MODELS HAVE A GENERAL AGREEMENT ON THE PATTERN...BUT DISPLAY SUBTLE DIFFERENCES THAT COULD HAVE MAJOR SNOW/COLD IMPLICATIONS. WILL STAY WITH A CONSENSUS GFS/EC MIX AND KEEP THE MAJORITY OF THE FORECAST IN TACT. FOR TODAY...VERY IMPRESSIVE SURFACE PRESSURE FALLS WERE OCCURRING OVER NORTHERN MONTANA...RIGHT ALONG THE CANADIAN BORDER. THIS WAS IN RESPONSE TO 170KT JET MAX SLIDING INTO NORTHEAST MONTANA. THIS SCENARIO WILL ALLOW A LEE TROUGH TO QUICKLY DEVELOP AND GENERATE STRONG WINDS AT LIVINGSTON THIS MORNING. WINDS ALREADY INCREASING WITH SOME GUSTS TO 50 MPH AT LIVINGSTON. SOME MODEL GUIDANCE HAS BACKED OFF ON WARNING TYPE OF WINDS...WHILE OTHER HAVE NOT. WILL KEEP WARNING GOING. THE FORMATION OF A SURFACE LOW FROM THE PRESSURE FALLS OVER THE NORTH WILL HAVE HUGE RAMIFICATIONS ON OUR FORECAST TODAY. A FARTHER NORTHWARD DEVELOPING LOW WOULD ALLOW FOR MORE DOWNSLOPE FLOW OVER SOUTH CENTRAL MONTANA. THIS WOULD PROVIDE A WARMER MORNING AND PUSH SOME OF THE HEAVIER SNOW EASTWARD AWAY FROM BILLINGS. A FARTHER SOUTH LOW WOULD BE COLDER AND BRING THE HEAVIER SNOW SOUTH AND WEST INTO BILLINGS. RADAR IMAGERY WAS FILLING IN OVER WESTERN AND CENTRAL ZONES THIS MORNING...BUT HAS SHOWN A DOWNSLOPE SIGNATURE OVERNIGHT. LOOKS LIKE THE RADAR IS FILLING IN SIMILARLY TO THE HRRR WHICH PUTS THE HEAVIEST SNOW EAST OF BILLINGS THIS MORNING WITH LIGHTER SNOW OVER WESTERN YELLOWSTONE COUNTY. WILL GO IN THAT DIRECTION AND LIGHTEN UP MORNING SNOWFALL OVER BILLINGS. STRONG WARM AIR ADVECTION WILL SPREAD HEAVIER SNOW EAST OF BILLINGS INTO SOUTHEAST MONTANA AND ADVISORIES FOR THE EAST LOOK GOOD. ONCE THE SURFACE LOW DROPS INTO NORTHEAST WYOMING...THE REINFORCING ARCTIC SURGE WILL DRIVE BACK IN WITH FALLING TEMPERATURES IN THE AFTERNOON AND SNOW DEVELOPING. THIS IS THE PERIOD OF HEAVIEST SNOW FOR BILLINGS...THIS AFTERNOON AND EVENING. ARCTIC SHOULD GET INTO WESTERN ZONES TOO AND THE FOOTHILLS WILL RECEIVE STRONG UPSLOPE FLOW THIS AFTERNOON AND TONIGHT. WILL ISSUE A WINTER WEATHER ADVISORY FOR THE BEARTOOTH AND RED LODGE FOOTHILLS FOR THIS TIME PERIOD. LIVINGSTON WILL BE A CHALLENGE TODAY BECAUSE WARMER AIR WILL KEEP ACCUMULATIONS DOWN...BUT BLOWING SNOW WILL BE AN ISSUE THIS MORNING. ALSO...BELIEVE THE ARCTIC WILL SURGE BACK IN THERE LATE THIS AFTERNOON. LIVINGSTON COULD GET WARNING AMOUNTS AS INSTABILITY WAS DECENT WITH 850-500MB LAPSE RATES APPROACHING 6C. WILL NEED TO BE WATCHED. ARCTIC BOUNDARY HANGS UP OVER WESTERN ZONES TONIGHT AND WILL GET AN OVER RUNNING SNOWFALL FOR TONIGHT THROUGH TUESDAY NIGHT. MODELS KEEP THE FOOTHILLS OUT OF THE BEST OVER RUNNING WITH 700MB WINDS REMAINING OUT OF THE NORTHWEST. THEREFORE WILL LIMIT THE ADVISORIES OF NYE AND RED LODGE TO TODAY AND TONIGHT. SHOULD SEE 2 TO 4 INCH SNOW TOTALS EACH 12 HOURS THROUGH TUESDAY NIGHT OVER THE REST OF THE FORECAST AREA. THE SNOW WILL COME TO AN END LATE TUESDAY NIGHT. TWH .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... FOR THE EXTENDED...MODELS CONTINUE TO SHOW THE REPRIEVE FROM THE SNOWFALL WEDNESDAY. THE RIDGE ALONG THE WEST COAST WILL PUSH EAST...MOVING THE ARCTIC AIR OUT OF THE AREA. TEMPERATURES WILL RETURN MORE NORMAL VALUES...THOUGH THE EASTERN PLAINS MAY NOT HAVE AS MUCH OF A RECOVERY. THURSDAY ANOTHER SHORTWAVE WILL MOVE THROUGH THE NORTHWEST FLOW. THIS WILL PROVIDE JUST ENOUGH INSTABILITY THAT MORE COLD AND SOME LIGHT SNOW WILL MOVE BACK INTO THE AREA. FORCING IS VERY WEAK WITH THIS...SO CONTINUE TO EXPECT MUCH LIGHTER SNOWFALL ACCUMULATIONS. ANOTHER WEAK WAVE WILL MOVE THROUGH SUNDAY GIVING THE AREA ANOTHER SHOT AT SOME LIGHT SNOW. AGAIN NOT MUCH FORCING WITH THIS SO AMOUNTS WILL BE MUCH LIGHTER. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL GOING THROUGH THE WEEKEND. THERE IS SUBTLE TIMING DIFFERENCES BETWEEN THE MODELS...SO CURRENTLY GOING WITH A BLEND. ONE CAVEAT WITH TEMPERATURES THROUGH THE EXTENDED WILL BE HOW MUCH SNOW PACK IS ON THE GROUND. REIMER && .AVIATION... STRONG WIND GUSTS AROUND 45 KTS WILL CONTINUE IN THE KLVM AREA THROUGH THE REMAINDER OF THE MORNING RESULTING IN REDUCED VISIBILITIES DUE TO BLOWING SNOW. AREAS OF LIGHT TO MODERATE SNOW WILL CONTINUE ACROSS THE ENTIRE AREA TODAY. THE KBIL AREA MAY CONTINUE TO SEE A BREAK IN THE SNOW THROUGH MOST OF THE DAY BUT THE HEAVIER SNOW IS EXPECTED TO MOVE BACK IN BY LATE AFTERNOON. MVFR TO IFR CONDITIONS WILL PREVAIL TODAY WITH AREAS OF LIFR IN THE HEAVIER SNOW BANDS. THE MOUNTAINS WILL BE OBSCURED THROUGHOUT THE DAY. HOOLEY && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 035 009/012 000/027 018/024 004/015 009/023 014/028 +/S +9/S 71/B 01/B 22/J 22/J 21/B LVM 040 023/029 010/043 026/034 014/029 019/034 021/036 9/O 97/S 51/B 01/B 12/J 22/J 21/B HDN 028 007/016 904/023 013/025 000/018 006/023 008/028 +/S +9/S 71/B 01/B 21/E 22/J 11/B MLS 015 904/009 915/017 010/017 907/008 902/017 002/021 9/S 47/S 31/B 12/J 11/B 21/B 11/B 4BQ 029 003/012 909/023 015/022 902/014 005/022 007/024 +/S 67/S 51/B 02/J 11/B 21/B 11/B BHK 014 904/007 916/015 009/015 905/006 901/016 002/019 8/S 25/S 20/B 12/J 11/B 22/J 11/B SHR 035 011/020 001/030 021/030 003/021 012/029 011/030 +/O 97/S 61/B 01/B 12/J 22/J 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST WEDNESDAY FOR ZONES 28-31>34-36-37-39-41-42-65. WINTER STORM WARNING IN EFFECT UNTIL 6 AM MST WEDNESDAY FOR ZONES 29-30-35-38-40-57-58-63-67-68. WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST TUESDAY FOR ZONES 56-66. WY...WINTER STORM WARNING IN EFFECT UNTIL 6 AM MST WEDNESDAY FOR ZONE 98. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
910 AM MST MON JAN 5 2015 .UPDATE... THE MAIN FORECAST CHANGE THIS MORNING WAS TO LOWER SNOW TOTALS FOR TODAY OVER SOUTH CENTRAL MT...ESPECIALLY AROUND BILLINGS. THE LOW- LEVEL DOWNSLOPE FLOW ON THE SOUTH SIDE OF A SURFACE LOW LOCATED IN CENTRAL MT NEAR LEWISTOWN AS OF 16 UTC IS INHIBITING SNOWFALL THUS FAR THIS MORNING...AND THIS SITUATION WILL NOT CHANGE MUCH THROUGH THE MID TO LATE AFTERNOON WHEN THE ARCTIC FRONT RUSHES SOUTH...AND THE WINDS SWITCH BACK AROUND THE THE NORTHEAST IN BILLINGS. RECENT HIGH-RESOLUTION MODEL GUIDANCE SUGGESTS THAT MIGHT NOT OCCUR UNTIL VERY LATE AFTERNOON AND IN SOME OF THOSE SIMULATIONS NOT UNTIL THE EARLY EVENING HOURS. SO...WE CUT BACK ON SNOWFALL TOTALS TODAY FOR THE CITY AND SURROUNDING AREAS. THE ARCTIC FRONT JUST SURGED SOUTH THROUGH GREAT FALLS AT 9 AM...WHICH TYPICALLY MEANS IT COULD REACH BILLINGS BY 3 PM WITH SNOW THEN PICKING UP AFTER THAT TIME. WE ARE STILL CARRYING ABOUT 2 INCHES TOTAL FOR TODAY IN BILLINGS...BUT IT LOOKS LIKE IF WE GET THAT MUCH IT WILL BE MAINLY IN THE AFTERNOON. IN CONTRAST...SNOW IS FALLING LIKE EXPECTED IN SOUTHEASTERN MT AND VISIBILITY IS REDUCED TO 1/2SM IN MILES CITY AND BAKER AT THE MID- MORNING HOUR. WE STILL EXPECT 3 TO 6 INCHES OF SNOW IN TOTAL TODAY OVER SOUTHEASTERN MT. WE ARE CHOOSING TO LEAVE THE HIGH WIND WARNING UP AT LIVINGSTON AT THIS POINT GIVEN TRAVEL IMPACTS THERE...EVEN THOUGH WINDS ARE THUS FAR NOT NOT AS STRONG AS EXPECTED. WE WILL REVISIT THAT DURING THE LATE MORNING HOURS...ALONG WITH THE REST OF THE FORECAST FOR TODAY AND INTO TONIGHT...WHICH IS A VERY DIFFICULT ONE WHICH MAY REQUIRE FURTHER ADJUSTMENTS. SCHULTZ && .SHORT TERM...VALID FOR TDY AND TUE... VERY COMPLEX AND DYNAMIC WEATHER PATTERN TODAY...AND ONE THAT WILL BE VERY DIFFICULT TO PINPOINT EXACT RESULTS...EVEN THIS CLOSE IN TIME. MODELS HAVE A GENERAL AGREEMENT ON THE PATTERN...BUT DISPLAY SUBTLE DIFFERENCES THAT COULD HAVE MAJOR SNOW/COLD IMPLICATIONS. WILL STAY WITH A CONSENSUS GFS/EC MIX AND KEEP THE MAJORITY OF THE FORECAST IN TACT. FOR TODAY...VERY IMPRESSIVE SURFACE PRESSURE FALLS WERE OCCURRING OVER NORTHERN MONTANA...RIGHT ALONG THE CANADIAN BORDER. THIS WAS IN RESPONSE TO 170KT JET MAX SLIDING INTO NORTHEAST MONTANA. THIS SCENARIO WILL ALLOW A LEE TROUGH TO QUICKLY DEVELOP AND GENERATE STRONG WINDS AT LIVINGSTON THIS MORNING. WINDS ALREADY INCREASING WITH SOME GUSTS TO 50 MPH AT LIVINGSTON. SOME MODEL GUIDANCE HAS BACKED OFF ON WARNING TYPE OF WINDS...WHILE OTHER HAVE NOT. WILL KEEP WARNING GOING. THE FORMATION OF A SURFACE LOW FROM THE PRESSURE FALLS OVER THE NORTH WILL HAVE HUGE RAMIFICATIONS ON OUR FORECAST TODAY. A FARTHER NORTHWARD DEVELOPING LOW WOULD ALLOW FOR MORE DOWNSLOPE FLOW OVER SOUTH CENTRAL MONTANA. THIS WOULD PROVIDE A WARMER MORNING AND PUSH SOME OF THE HEAVIER SNOW EASTWARD AWAY FROM BILLINGS. A FARTHER SOUTH LOW WOULD BE COLDER AND BRING THE HEAVIER SNOW SOUTH AND WEST INTO BILLINGS. RADAR IMAGERY WAS FILLING IN OVER WESTERN AND CENTRAL ZONES THIS MORNING...BUT HAS SHOWN A DOWNSLOPE SIGNATURE OVERNIGHT. LOOKS LIKE THE RADAR IS FILLING IN SIMILARLY TO THE HRRR WHICH PUTS THE HEAVIEST SNOW EAST OF BILLINGS THIS MORNING WITH LIGHTER SNOW OVER WESTERN YELLOWSTONE COUNTY. WILL GO IN THAT DIRECTION AND LIGHTEN UP MORNING SNOWFALL OVER BILLINGS. STRONG WARM AIR ADVECTION WILL SPREAD HEAVIER SNOW EAST OF BILLINGS INTO SOUTHEAST MONTANA AND ADVISORIES FOR THE EAST LOOK GOOD. ONCE THE SURFACE LOW DROPS INTO NORTHEAST WYOMING...THE REINFORCING ARCTIC SURGE WILL DRIVE BACK IN WITH FALLING TEMPERATURES IN THE AFTERNOON AND SNOW DEVELOPING. THIS IS THE PERIOD OF HEAVIEST SNOW FOR BILLINGS...THIS AFTERNOON AND EVENING. ARCTIC SHOULD GET INTO WESTERN ZONES TOO AND THE FOOTHILLS WILL RECEIVE STRONG UPSLOPE FLOW THIS AFTERNOON AND TONIGHT. WILL ISSUE A WINTER WEATHER ADVISORY FOR THE BEARTOOTH AND RED LODGE FOOTHILLS FOR THIS TIME PERIOD. LIVINGSTON WILL BE A CHALLENGE TODAY BECAUSE WARMER AIR WILL KEEP ACCUMULATIONS DOWN...BUT BLOWING SNOW WILL BE AN ISSUE THIS MORNING. ALSO...BELIEVE THE ARCTIC WILL SURGE BACK IN THERE LATE THIS AFTERNOON. LIVINGSTON COULD GET WARNING AMOUNTS AS INSTABILITY WAS DECENT WITH 850-500MB LAPSE RATES APPROACHING 6C. WILL NEED TO BE WATCHED. ARCTIC BOUNDARY HANGS UP OVER WESTERN ZONES TONIGHT AND WILL GET AN OVER RUNNING SNOWFALL FOR TONIGHT THROUGH TUESDAY NIGHT. MODELS KEEP THE FOOTHILLS OUT OF THE BEST OVER RUNNING WITH 700MB WINDS REMAINING OUT OF THE NORTHWEST. THEREFORE WILL LIMIT THE ADVISORIES OF NYE AND RED LODGE TO TODAY AND TONIGHT. SHOULD SEE 2 TO 4 INCH SNOW TOTALS EACH 12 HOURS THROUGH TUESDAY NIGHT OVER THE REST OF THE FORECAST AREA. THE SNOW WILL COME TO AN END LATE TUESDAY NIGHT. TWH .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... FOR THE EXTENDED...MODELS CONTINUE TO SHOW THE REPRIEVE FROM THE SNOWFALL WEDNESDAY. THE RIDGE ALONG THE WEST COAST WILL PUSH EAST...MOVING THE ARCTIC AIR OUT OF THE AREA. TEMPERATURES WILL RETURN MORE NORMAL VALUES...THOUGH THE EASTERN PLAINS MAY NOT HAVE AS MUCH OF A RECOVERY. THURSDAY ANOTHER SHORTWAVE WILL MOVE THROUGH THE NORTHWEST FLOW. THIS WILL PROVIDE JUST ENOUGH INSTABILITY THAT MORE COLD AND SOME LIGHT SNOW WILL MOVE BACK INTO THE AREA. FORCING IS VERY WEAK WITH THIS...SO CONTINUE TO EXPECT MUCH LIGHTER SNOWFALL ACCUMULATIONS. ANOTHER WEAK WAVE WILL MOVE THROUGH SUNDAY GIVING THE AREA ANOTHER SHOT AT SOME LIGHT SNOW. AGAIN NOT MUCH FORCING WITH THIS SO AMOUNTS WILL BE MUCH LIGHTER. TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL GOING THROUGH THE WEEKEND. THERE IS SUBTLE TIMING DIFFERENCES BETWEEN THE MODELS...SO CURRENTLY GOING WITH A BLEND. ONE CAVEAT WITH TEMPERATURES THROUGH THE EXTENDED WILL BE HOW MUCH SNOW PACK IS ON THE GROUND. REIMER && .AVIATION... STRONG WIND GUSTS AROUND 45 KTS WILL CONTINUE IN THE KLVM AREA THROUGH THE REMAINDER OF THE MORNING RESULTING IN REDUCED VISIBILITIES DUE TO BLOWING SNOW. AREAS OF LIGHT TO MODERATE SNOW WILL CONTINUE ACROSS THE ENTIRE AREA TODAY. THE KBIL AREA MAY CONTINUE TO SEE A BREAK IN THE SNOW THROUGH MOST OF THE DAY BUT THE HEAVIER SNOW IS EXPECTED TO MOVE BACK IN BY LATE AFTERNOON. MVFR TO IFR CONDITIONS WILL PREVAIL TODAY WITH AREAS OF LIFR IN THE HEAVIER SNOW BANDS. THE MOUNTAINS WILL BE OBSCURED THROUGHOUT THE DAY. HOOLEY && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 028 009/012 000/027 018/024 004/015 009/023 014/028 +/S +9/S 71/B 01/B 22/J 22/J 21/B LVM 040 023/029 010/043 026/034 014/029 019/034 021/036 9/O 97/S 51/B 01/B 12/J 22/J 21/B HDN 028 007/016 904/023 013/025 000/018 006/023 008/028 +/S +9/S 71/B 01/B 21/E 22/J 11/B MLS 015 904/009 915/017 010/017 907/008 902/017 002/021 +/S 47/S 31/B 12/J 11/B 21/B 11/B 4BQ 029 003/012 909/023 015/022 902/014 005/022 007/024 +/S 67/S 51/B 02/J 11/B 21/B 11/B BHK 014 904/007 916/015 009/015 905/006 901/016 002/019 +/S 25/S 20/B 12/J 11/B 22/J 11/B SHR 035 011/020 001/030 021/030 003/021 012/029 011/030 +/O 97/S 61/B 01/B 12/J 22/J 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST WEDNESDAY FOR ZONES 28-31>34-36-37-39-41-42-65. WINTER STORM WARNING IN EFFECT UNTIL 6 AM MST WEDNESDAY FOR ZONES 29-30-35-38-40-57-58-63-67-68. WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 AM MST TUESDAY FOR ZONES 56-66. HIGH WIND WARNING IN EFFECT UNTIL NOON MST TODAY FOR ZONES 65-66. WY...WINTER STORM WARNING IN EFFECT UNTIL 6 AM MST WEDNESDAY FOR ZONE 98. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
344 PM CST MON JAN 5 2015 .SYNOPSIS... ISSUED AT 342 PM CST MON JAN 5 2015 WARM FRONT ALOFT MOVING EAST ACROSS THE CWA THIS AFTERNOON. HIGHER TERRAIN TO THE WEST HELPING MIX THE WARMER AIR ALOFT TO THE SFC...BFF AND IBM IN THE PANHANDLE ARE IN THE 40S. MEANWHILE FURTHER EAST THE SNOWPACK AND LOWER LEVELS OF MOST OF THE CWA RESULTING IN LESS MIXING AND TEMPS IN THE TEENS AND 20S. DISTURBANCE THAT BROUGHT SNOW TO N CENTRAL MOST OF THE DAY HAS DRIFTED EAST WITH MOST REPORTS NOW ONLY SEEING FLURRIES IF ANYTHING. A SECONDARY DISTURBANCE IS CROSSING THE BLACK HILLS...ALTHOUGH THE TEMP THERE WAS ABOVE FREEZING /AS WAS THE TEMPS OF THE LOWER LEVELS/ SO PRECIP WAS LIQUID EARLIER. THE NEXT COLD FRONT IS STARTING TO PUSH SE ACROSS WESTERN S DAKOTA AND RAP HAS COOLED OFF WITH THE 21Z OB HAVING CHANGE BACK TO SNOW. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 342 PM CST MON JAN 5 2015 ANOTHER COMPLICATED FORECAST WITH SEVERAL CONCERNS OVER THE NEXT 24 HOURS. FIRST OFF IS EVENING TEMPERATURES. 850 MB TEMPS ACROSS MUCH OF THE CWA IN POSITIVE C TERRITORY...HOWEVER MIXING IS LIMITED DO TO CLOUDS...SNOW PACK...AND JANUARY SUN ANGLE. A COLD FRONT IS BEGINNING TO PUSH SOUTH ACROSS THE AREA...AND WILL CONTINUE TO DO SO OVERNIGHT. ALONG AND BEHIND THE FRONT WINDS SWITCH TO THE NORTHWEST AND ARE GUSTY. THIS GUSTINESS ALONG THE FRONT MAY ACTUALLY HELP CAUSE A BUMP IN TEMPS. WITH SUCH WARM 850 MB TEMPS...THE MIXING MAY CAUSE TEMPS TO SURGE BRIEFLY INTO THE 30S. THIS IS EXPECTED ACROSS THE HIGHER TERRAIN OF THE WESTERN CWA...MORE UNCERTAINTY ACROSS THE CENTRAL AND EAST. MEANWHILE AN UPPER LEVEL DISTURBANCE SLIDES FROM THE BLACK HILLS TO THE SE. A FEW RADAR RETURNS ACROSS SW SOUTH DAKOTA AND INTO PARTS OF NORTHERN NEB. THE WARM LOWER LEVEL IS ALSO DRY AND EXPECT LITTLE MOISTURE TO MAKE IT TO THE GROUND. THAT SAID...CAN NOT RULE OUT A FEW ISOLATED FLURRIES THIS EVENING. THE NW FLOW AROUND THE HILLS CONVERGES NEAR PINE RIDGE AND COULD SEE SOME LIGHT SNOW THERE AS WELL. AGAIN SOME CONCERN FOR THE DRY LOWER LEVELS LIMITING ANYTHING REACHING THE GROUND AND POPS ARE LOW. OVERNIGHT TEMPERATURES DO FINALLY DROP AFTER THE FRONT IS SOUTH OF THE AREA...ALTHOUGH CLOUDS LINGER AS A BLANKET AND LIMIT COOLING. LOWS GENERALLY BOTTOM OUT IN THE SINGLE DIGITS ABOVE ZERO TO THE TEENS. TOMORROW ARRIVES THE NEXT SHORT WAVE IN THE FAST MOVING NW FLOW REGIME. NORTHERN NEBRASKA HAS THE BEST CHANCE FOR SNOWFALL. LIFT IS MARGINAL IN THE NARROW DENDRITIC GROWTH ZONE...AND SHOULD COMBINE WITH THE FAST MOVING SYSTEM TO LIMIT SNOW ACCUMULATION TO LESS THAN AN INCH DURING THE DAYTIME. HIGHS STRUGGLE INTO THE TEENS DUE TO THE CLOUDS/LIGHT SNOW ACROSS NORTHERN NEB...ESPECIALLY NORTH CENTRAL. WARMER IN THE SW...MID 20S TO NEAR FREEZING...ALTHOUGH THIS MAY BE OPTIMISTIC DUE TO THE SNOW PACK. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 342 PM CST MON JAN 5 2015 THE NEXT AIR MASS WILL MOVE ONTO THE CENTRAL PLAINS TUESDAY NIGHT AND WEDNESDAY. THE TEMPERATURE OF THE AIR IS EXPECTED TO BE 5-15F COLDER IN EASTERN NEBRASKA THAN IN CENTRAL AND WESTERN NEBRASKA. THE COLDER TEMPERATURES IN NORTH CENTRAL NEBRASKA ARE LOCATED WHERE THE STRONGEST WIND IS EXPECTED. THEREFORE...WIND CHILLS OF -20F TO -25F APPEAR TO BE A GOOD BET...POSSIBLY EVEN NEAR -30F FOR NORTH CENTRAL NEBRASKA NEAR THE NIOBRARA. ANOTHER FORECAST ISSUE IS THE POTENTIAL FOR LIGHT SNOW WITH THE ARCTIC FRONT. WITH THE AIR MASS SO STRONG...THE SYSTEM-RELATIVE LIFT IS LIKELY TO BE SIGNIFICANT IN THE 280-300K LAYER WITH THE BEST LIFT IN NORTHERN NEBRASKA. A CROSS SECTION OF THE AGEOSTROPHIC VERTICAL CIRCULATION THROUGH NORTH CENTRAL-SOUTHWEST NEBRASKA INDICATES THAT THE THERE DOES NOT APPEAR TO BE LOT OF ENHANCEMENT FROM FRONTOGENESIS OR INSTABILITY. WITH THE LOW PRECIPITATION AMOUNTS INDICATED IN THE MODELS...CONFIDENCE IS NOT HIGH AND WE WILL KEEP THE PROBABILITY FAIRLY LOW. AS LOW LEVEL FLOW RETURNS TO A SOUTHERLY DIRECTION...HIGHER TEMPERATURES CAN BE EXPECTED THURSDAY. A FRONT SAGS BACK TO THE SOUTHWEST AS ANOTHER ARCTIC AIRMASS GOES THROUGH CENTRAL AND EASTERN NEBRASKA. IN FACT...WITH ARCTIC AIR MASSES GOING THROUGH EVERY TWO DAYS...TEMPERATURES WILL VARY WIDELY FROM ONE DAY TO THE NEXT. AS THE FRONTS GO THROUGH...THERE IS A POSSIBILITY OF PRECIPITATION BUT THE CHANCES...IF ANY...WILL BE LOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1215 PM CST MON JAN 5 2015 SNOW IS DIMINISHING ACROSS N CENTRAL NEB...INCLUDING VALENTINE...AND ONLY SEE ANOTHER HOUR OR TWO OF LIGHT SNOWFALL POSSIBLE AT THE TERMINAL. BRIEF MVFR VISIBILITIES ARE POSSIBLE OTHERWISE TREND TO VFR OVERCAST SKIES EXPECTED. SOUTHERLY WINDS GUSTING TO 20 TO 30 KTS THIS AFTERNOON...BECOME NORTHWESTERLY AND CONTINUED GUSTY BEHIND THE COLD FRONT WHICH PUSHES SOUTHEAST ACROSS THE AREA. ALSO ASSOCIATED WITH AND BEHIND THE FRONT WILL LIKELY BE LOWERING MVFR CIGS. BY EARLY MORNING...WINDS WILL BECOME LIGHT AND VARIABLE. ALSO EXPECT THE CIGS TO BE IMPROVING TO VFR ACROSS NORTHERN NEBRASKA. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...MASEK SHORT TERM...MASEK LONG TERM...SPRINGER AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
310 PM CST MON JAN 5 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 310 PM CST MON JAN 5 2015 FORECAST PRETTY MUCH IN LINE WITH PREVIOUS THINKING AS A BROAD AREA OF MODERATE TO OCCASIONALLY HEAVY SNOW IS PRESENTLY OCCURRING OVER ALL BUT FAR SOUTH CENTRAL SOUTH DAKOTA THIS AFTERNOON. THIS IN ASSOCIATION WITH AN INTENSIFYING 700 MB FRONT AND AN APPROACHING UPPER LEVEL SHORTWAVE DROPPING INTO WESTERN NORTH DAKOTA/NORTH CENTRAL SOUTH DAKOTA AT THIS TIME. CURRENT RADAR SHOWING ENHANCED RETURNS THROUGH THE CENTRAL AND SOUTHERN INTERSTATE 29 CORRIDOR INTO NORTHWESTERN IOWA...ALIGNED FAIRLY WELL WITH WHERE MODEL PROGGED FRONTOGENESIS LOOKS TO BE STRONGEST. EXPECT ENHANCEMENT TO CONTINUE THROUGH THE LATE AFTERNOON AS THE AFOREMENTIONED SHORTWAVE SLIDES THROUGH OUR AREA. THE RAP DOES INDICATE SOME SLIGHT INSTABILITY ABOVE THE FRONTAL CIRCULATION FOR LATE AFTERNOON...WHICH COULD RESULT IN A NARROWER BAND OF HEAVIER SNOW THROUGH NORTHWESTERN IOWA DURING THE LATE AFTERNOON...WHICH ALIGNS WELL WITH OUR CURRENT SNOWFALL GRIDS. THIS IN COMBINATION WITH SNOW RATIOS IN THE RANGE OF 15 TO 25:1 IN A DEEPER DENDRITIC LAYER COULD RESULT IN HOURLY SNOWFALL RATES OF 1 INCH TO 1 1/2 INCH THROUGH THE AFTERNOON BEFORE FORCING BEGINS TO WANE IN THE EARLY EVENING. FORECASTED SNOWFALL TOTALS STILL LOOKING AT JUST EITHER SIDE OF 6 INCHES ORIENTED FROM THE CENTRAL AND EASTERN HIGHWAY 14 CORRIDOR THEN SOUTHEASTWARD THROUGH THE CENTRAL INTERSTATE 29 CORRIDOR INTO SOUTHWESTERN MINNESOTA...TRENDING UPWARD TO AROUND 7 INCHES IN PARTS OF NORTHWESTERN IOWA. BLOWING SNOW SHOULD ONLY BE A RELATIVELY MINOR ISSUE WITH WINDS STAYING IN THE 15 TO 25 KT RANGE MAINLY ACROSS AREAS TO THE SOUTH OF INTERSTATE 90. SNOW SHOULD QUICKLY END BY MID EVENING AS FRONTAL FORCING WEAKENS AND THE SHORTWAVE PUSHES OFF TO THE EAST. IT WILL BE ANOTHER VERY COLD NIGHT WITH LOWS DOWN INTO MAINLY SINGLE DIGITS BELOW ZERO. DO BEGIN TO SEE WIND CHILL ADVISORY CRITERIA BEING MET LATER TONIGHT...BUT ELECTED TO HOLD OFF ON THAT UNTIL CURRENT HEADLINES EXPIRE. MIDDLE AND HIGH CLOUDS WILL AGAIN INCREASE FROM THE WEST TUESDAY AS THE NEXT CANADIAN WAVE BEGINS TO DEEPEN THE UPPER TROUGH. MOST OF THE INCREASE WILL BE ACROSS THE SOUTHWEST HALF OF THE AREA...AND WILL KEEP A MENTION OF FLURRIES THERE WITH LITTLE DYNAMIC LIFT FOR MEASURABLE SNOW. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 310 PM CST MON JAN 5 2015 SKIES WILL CLEAR TUESDAY NIGHT AS THE WAVE CONTINUES TO DIG AND THE ARCTIC RESURGENCE POURS INTO THE FORECAST AREA WITH THE COLDEST AIR OF THE WINTER SO FAR. WINDS BRINGING THIS SURGE WILL BE STRONG TO CAUSE SOME BLOWING OF THE STILL FRESH SNOW COVER...WILL MENTION TUESDAY NIGHT AND TAPER OFF WEDNESDAY AS WINDS SLOWLY DECREASE. SKIES WEDNESDAY SHOULD BE PRETTY CLEAR. HOWEVER THE BIG NEWS WILL BE THE WIND CHILLS DIVING TO WARNING LEVELS BY LATE TUESDAY NIGHT... EXCEPT TO ONLY ADVISORY CRITERIA OVER THE SOUTHWEST CORNER OF THE AREA. AFTER COORDINATION AND LOCAL INPUT...HAVE DECIDED TO HOLD OFF ON THESE HIGHLIGHTS UNTIL THE CURRENT WARNING AND ADVISORY TONE DOWN. HOWEVER...THOUGH IT WAS ALREADY BEEN COLD OF COURSE...THIS IS GOING TO BE THE COLDEST SHOT OF THE WINTER SO FAR. WEDNESDAY NIGHT WILL BRING A QUICK TURN TO WARMING...THOUGH IT WILL GET TO THE SURFACE IN ONLY A VERY LIMITED MEASURE. A BAND OF WARM ADVECTION CLOUDS WILL PASS OVER THE AREA WITH THIS WARMING AND EXIT AS THE NEXT COLD AIR SHOT ARRIVES. THE TRANSITORY NATURE OF THE WARMING LEADS TO A MENTION OF ONLY A SLIGHT CHANCE OF LIGHT SNOW IN THE NORTHEAST CORNER OF THE AREA LATE WEDNESDAY NIGHT. THURSDAY WILL BE NOT AS COLD...MOSTLY TEENS ABOVE ZERO...AS DELAYED MIXING FROM THE WEDNESDAY NIGHT WARMING HELPS TEMPERATURES UP A BIT. THE ACCOMPANYING COLD AIR REINFORCEMENT WILL MAKE FOR ANOTHER WIND CHILL EVENT WITH A COLD DAY FRIDAY. THE COLDEST AIR WILL THEN SHIFT EAST OF THE AREA WITH RELATIVELY MINOR WAVES AND BELOW NORMAL BUT NOT AS FRIGID TEMPERATURES IN STORE FOR SATURDAY THROUGH MONDAY. WILL MENTION SOME CHANCE OF LIGHT SNOW CENTRAL AND SOUTH SATURDAY AHEAD OF THE NEXT CANADIAN HIGH...WHICH SHOULD RULE WITH DRY WEATHER AND MODESTLY COLD TEMPERATURES AS MENTIONED ABOVE FOR SUNDAY AND MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1152 AM CST MON JAN 5 2015 SNOW BAND BECOMING ESTABLISHED ACROSS THE AREA WITH WIDESPREAD VISIBILITIES OF 1/2 TO 1SM. LIFR OR WORSE WILL BE THE RULE THE NEXT 3-6 HOURS...BUT SHOULD IMPROVE QUICKLY IN TERMS OF VISIBILITY AND CEILING LATER IN THE AFTERNOON AND EARLY EVENING FROM WEST TO EAST. WINDS LOOK POTENTIALLY A BIT LIGHT IN GUIDANCE FOR LOCATIONS WEST OF THE INVERTED TROUGH DURING THE EVENING AND EARLY OVERNIGHT MAINLY FROM THE JAMES THROUGH MISSOURI RIVER CORRIDORS. DOUBTS AS TO IF WINDS WOULD BE STRONG ENOUGH TO PRODUCE ANY APPRECIABLE BLOWING SNOW...BUT KSUX WOULD BE THE GREATEST RISK FOR ANY TAF LOCATION. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR SDZ070- 071. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR SDZ039-040- 054>056-061-062-066-067. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR SDZ038- 052-053-058>060-064-065-068-069. MN...WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR MNZ071-072- 080-081-089-090-097-098. IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ031. WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR IAZ001>003- 012>014-020>022-032. NE...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ013- 014. && $$ SHORT TERM...JM LONG TERM... AVIATION...CHAPMAN