Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/28/15


AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
755 PM PST TUE JAN 27 2015 .UPDATE... LATEST SATELLITE IMAGERY SHOWED UPPER LEVEL WAVE LIFTING OUT OF WESTERN NV AND THE EASTERN SIERRA THIS EVENING WITH BROAD BAND OF RADAR ECHOES SHOWING AN OVERALL DECREASE IN COVERAGE THE PAST HOUR. SURFACE OBSERVATIONS ARE CONFIRMING THIS TREND SHOWING AN END TO LIGHT PRECIPITATION. BOTH THE 00Z GFS/NAM ALONG WITH THE LATEST HRRR INDICATE THAT ALL PRECIPITATION WILL END BY MIDNIGHT. SO WE HAVE UPDATED TO DECREASE POPS TO SLIGHT CHANCE THIS EVENING AND REMOVE THEM IN ALL AREAS BUT EASTERN PORTIONS OF THE BASIN AND RANGE OVERNIGHT. OTHERWISE, ABUNDANT MOISTURE WILL BE LEFT BEHIND AND KEEP SKIES MOSTLY CLOUDY. IF THERE ARE ANY BREAKS IN THE CLOUDS LATE TONIGHT, PATCHY FOG/FREEZING FOG IS POSSIBLE. HOHMANN && .SYNOPSIS... THE LOW PRESSURE SYSTEM THAT BROUGHT RAIN AND MOUNTAIN SNOW WILL CONTINUE TO EXIT WITH ABUNDANT MOISTURE AND CLOUD COVER LINGERING THROUGH THURSDAY. A FEW SHOWERS ARE POSSIBLE SOUTH OF HIGHWAY 50 THURSDAY BEFORE DRIER CONDITIONS RETURN FOR THE WEEKEND. && .PREVIOUS DISCUSSION... /ISSUED 241 PM PST TUE JAN 27 2015/ SYNOPSIS... LOW PRESSURE WILL EXIT OUT OF THE REGION TONIGHT AS LIGHT VALLEY RAIN AND MOUNTAIN SNOW TAPERS OFF THIS EVENING. TEMPERATURES WILL COOL OFF THROUGH THE END OF THE WEEK WITH A FEW SHOWERS POSSIBLE SOUTH OF HIGHWAY 50 THURSDAY AND FRIDAY. DRIER CONDITIONS RETURN FOR THE WEEKEND BEFORE MOISTURE RETURNS TO THE NORTHWEST EARLY NEXT WEEK. SHORT TERM... VALLEY RAIN AND MOUNTAIN SNOW WILL TAPER OFF THIS EVENING AND OVERNIGHT AS LOW PRESSURE MOVES EAST OF THE AREA. WE STARTED SEEING STEADY LIGHT RAIN IN WESTERN NEVADA AS EARLY AS 4AM THIS MORNING WHICH THEN SPREAD NORTHWEST TO THE INTERSTATE 80 CORRIDOR AND TAHOE BASIN THROUGH THE MORNING HOURS. THE GREATEST PRECIPITATION AMOUNTS HAVE BEEN MAINLY AROUND THE FALLON AREA AS WELL AS IN THE CARSON RANGE WITH PRECIP TOTALS AROUND 0.25-0.30". OTHERWISE, PRECIP AMOUNTS HAVE BEEN PRETTY MEAGER AT LESS THAN 0.10". AROUND LAKE TAHOE AND DOWN INTO MONO COUNTY ABOVE 6500-7000 FEET, LIGHT SNOW AMOUNTS OF UP TO 3 INCHES WERE OBSERVED WITH ICY ROAD CONDITIONS REPORTED BETWEEN MOUNT ROSE SUMMIT AND INCLINE VILLAGE. AS THE LOW PRESSURE PUSHES INTO EASTERN NEVADA TONIGHT, THIS WILL SHIFT THE DEFORMATION ZONE FARTHER NORTH AND EAST AS WELL. NO FOG IS EXPECTED FOR TONIGHT IN THE SIERRA VALLEYS, DUE TO ABUNDANT CLOUDS. ALTHOUGH, IF WE CLEAR OUT OVERNIGHT, WE COULD SEE FOG BY EARLY TOMORROW MORNING. REGARDING DROUGHT IMPACTS, THIS LIGHT PRECIPITATION WILL HAVE VIRTUALLY NO EFFECT ON THE AREA`S LONG TERM DROUGHT. PUTTING THIS IN PERSPECTIVE, IT`S ONLY A DROP IN A BUCKET COMPARED TO THE DEFICIT WE HAVE FOR THE SIERRA AND WESTERN NEVADA. THIS RAIN DID, HOWEVER, PUSH JANUARY 2015 UP TO TIE FOR THE 7TH DRIEST JANUARY ON RECORD FOR THE RENO-TAHOE AIRPORT (AS OPPOSED BEING TIED FOR THE DRIEST ON RECORD BEFORE TODAY!). THE 0.06" OF RAIN THE AIRPORT OBSERVED TODAY IS THE ONLY MEASURABLE PRECIP WE`VE GOTTEN THIS MONTH. A WEAK SHORTWAVE RIDGE BUILDS OVER CA/NV ON WEDNESDAY ALTHOUGH ABUNDANT CLOUDS AND COOLER TEMPERATURES WILL REMAIN. A BAGGY TROUGH MOVES ONSHORE THURSDAY WITH MEAGER MOISTURE BEING PULLED UP FROM SOUTHERN CA/NV. WE LEFT IN A SLIGHT CHANCE OF LIGHT RAIN/SNOW SOUTH OF HIGHWAY 50 THURSDAY AND THURSDAY NIGHT AS THIS WEAK TROUGH TRANSITIONS OVER THE FORECAST AREA. BY FRIDAY, THIS LOW WILL STRENGTHEN AS IT MOVES INTO THE DESERT SOUTHWEST. AS IT CONSOLIDATES AND TIGHTENS UP, THIS SHOULD TAKE CLOUDS AND PRECIP INTO SOUTHERN NEVADA, LEAVING CLEARING SKIES AS HIGH PRESSURE BUILDS INTO NORTHERN CA/NV. HOON LONG TERM...SATURDAY THROUGH TUESDAY... GREATEST CHANGE TO THE FORECAST WAS TO ACCOUNT FOR THE MOIST FLOW MOVING INTO THE PACIFIC NORTHWEST EARLY NEXT WEEK WITH SMALL CHANCES PRECIPITATION MAY MAKE IT AS FAR SOUTH AS INTERSTATE 80. OTHERWISE, THE FORECAST REMAINS LARGELY UNCHANGED. POSITIVELY TILTED UPPER LEVEL RIDGE BUILDS INTO THE NORTHWEST SATURDAY PUSHING THE CLOSED LOW IN THE SOUTHWEST SOUTH INTO BAJA/NORTHERN MEXICO. EASTERLY WINDS WILL DEVELOP BETWEEN THESE TWO FEATURES WITH SIERRA RIDGE GUSTS POSSIBLY REACHING 60 TO 80 MPH SATURDAY, WEAKENING BY SUNDAY. AS THE RIDGE STRENGTHENS INTO SUNDAY IT WILL HELP KEEP SKIES MOSTLY CLEAR WITH HIGH TEMPERATURES CLIMBING 10 TO 12 DEGREES ABOVE NORMAL. THIS TRANSLATES TO MID 50S TO LOW 60S ACROSS MOST VALLEYS WITH 40S TO LOW 50S IN THE MOUNTAINS. A STREAM OF PACIFIC MOISTURE REACHES THE NORTHWEST COAST EARLY NEXT WEEK AND RECENT OPERATIONAL MODEL RUNS AND SEVERAL ENSEMBLES ARE SHOWING PRECIPITATION DEVELOPING ACROSS EXTREME NORTHERN CA/NV NORTHWARD. CONFIDENCE IN EXACTLY HOW FAR SOUTH PRECIPITATION WILL REACH IS LOW AT THIS POINT WITH ENSEMBLE MOISTURE TRANSPORT PLUMES AS FAR NORTH AS BRITISH COLUMBIA AND AS FAR SOUTH AS NORTHERN CALIFORNIA. FOR NOW HAVE ADDED A SLIGHT CHANCE OF SHOWERS MAINLY NORTH AND WEST OF A SOUTH LAKE TAHOE-GERLACH LINE MONDAY INTO TUESDAY OF NEXT WEEK. TEMPERATURES WILL REMAIN MILD AND SNOW LEVELS FAIRLY HIGH BEING ON THE SOUTH SIDE OF THE JET. DJ AVIATION... SCATTERED SHOWERS WILL PERSIST THROUGH THIS EVENING ACROSS THE SIERRA AND NORTHERN NEVADA BRINGING PERIODS OF MVFR-IFR CIGS/VIS. TEMPERATURES HAVE WARMED ENOUGH TO KEEP PRECIPITATION AS RAIN AT ALL TERMINALS, BUT ICING IS A CONCERN ALOFT. IN ADDITION, THERE IS WIDESPREAD MOUNTAIN OBSCURATION ACROSS THE REGION. GUSTY WESTERLY WINDS HAVE DEVELOPED THIS AFTERNOON, BUT ARE ONLY SURFACING IN SOME LOCATIONS, LIKELY RELATED TO WHERE SHOWERS ARE LOCATED. BE PREPARED FOR THE POSSIBILITY OF GUSTY WINDS UP TO 20 KTS IN WESTERN NEVADA. FOG IS UNLIKELY TO DEVELOP TONIGHT DUE TO LINGERING CLOUDS, BUT IF CLEARING OCCURS BY MORNING, FOG IS POSSIBLE IN SHELTERED VALLEYS, INCLUDING AT KTRK. CHANCES ARE ABOUT 15 PERCENT. DJ && .REV WATCHES/WARNINGS/ADVISORIES... NV...NONE. CA...NONE. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
219 PM PST MON JAN 26 2015 .SYNOPSIS...A WEAK STORM OVER SOUTHERN CALIFORNIA WILL SPREAD HIGH CLOUDS OVER THE BAY AREA TONIGHT WITH A CHANCE OF SHOWERS FOR THE CENTRAL COAST OVERNIGHT INTO TUESDAY MORNING. THE SYSTEM WILL MOVE EASTWARD BY TUESDAY NIGHT WITH DRY AND MILD WEATHER FORECAST WEDNESDAY THROUGH FRIDAY. A WARMING TREND IS FORECAST OVER THE WEEKEND AS HIGH PRESSURE STRENGTHENS. && .DISCUSSION...AS OF 2:19 PM PST MONDAY...TEMPERATURES IN THE BAY AREA ARE TRENDING SLIGHTLY WARMER THIS AFTERNOON DUE TO LESS FOG COVERAGE THIS MORNING. FARTHER SOUTH TEMPERATURES ALONG THE CENTRAL COAST ARE MUCH COOLER AFTER YESTERDAYS RECORD WARMTH...AS HIGH CLOUDS NOW BLANKET THE REGION IN ASSOCIATION WITH THE CIRCULATION LOCATED WEST OF SAN DIEGO. RIGHT NOW SOME RAIN IS FALLING IN THE DESERTS OF SOUTHERN CALIFORNIA WITH 29 PALMS AND CHINA LAKE REPORTING LIGHT RAIN LAST HOUR. ITS AN UNUSUAL SET-UP BUT ITS THE MOISTURE TO OUR SOUTH THAT WILL BE ADVECTED NORTHWARD OVER THE NEXT 12-18 HOURS. LATEST MODELS CONTINUE TO KEEP BEST CHANCES OF PRECIP EAST OF OUR DISTRICT BUT SOME OF THE MESO-SCALE MODELS PAINT SOME SHOWERS OVER THE HILLS OF MONTEREY AND SAN BENITO COUNTY AROUND SUNRISE TUESDAY AS THE SYSTEM BEGINS TO EJECT INLAND. IN PARTICULAR THE LATEST RAP MODEL RUNS HAVE TRENDED WETTER OVER MONTEREY/SAN BENITO COUNTY TUESDAY MORNING. HAVE LEFT SHOWER CHANCES IN THE FORECAST TO ACCOUNT FOR THIS. ANY SHOWER THREAT SHOULD END BY TUESDAY AFTERNOON AS THE MAIN UPPER LOW MOVES EASTWARD. AS THAT LOW MOVES TO OUR EAST THE SYNOPTIC PATTERN REMAINS FAIRLY NONDESCRIPT WITH WEAK CYCLONIC FLOW ALOFT THAT MAY GENERATE SOME SHOWERS OVER THE SIERRA BY THURSDAY BUT NO PRECIP FOR THE BAY AREA. OUR TEMPERATURES WILL TREND SLIGHTLY ABOVE NORMAL WITH AFTERNOON HIGHS IN THE 60S THROUGH THE WORK-WEEK. ANOTHER WARM WEEKEND LOOKS TO BE IN STORE AS A RIDGE BUILDS SATURDAY AND SUNDAY WITH 850 MB TEMPS TO AROUND 15 CELSIUS. DOESN`T LOOK AS WARM AS LAST WEEKEND SO NOT EXPECTING ANY RECORDS. THE PATTERN BEYOND SUNDAY BECOMES MORE MUDDLED. THE ECMWF AND GEM MODEL ARE ACTUALLY TRENDING A LITTLE WETTER WHILE THE GFS REMAINS DRY. GIVEN THE HISTORIC DRY PATTERN WERE UNDER WILL NOT BE INTRODUCING DAY 7 POPS AT THIS TIME. && .AVIATION...AS OF 9:50 AM PST MONDAY...PATCHY FOG IN THE VALLEYS WILL CLEAR BY LATE MORNING. A WEAK WEATHER SYSTEM MOVING INTO SOUTHERN CALIFORNIA WILL SPREAD CONSIDERABLE MID AND HIGH LEVEL CLOUDS ACROSS THE REGION THROUGH TUESDAY. MOSTLY VFR CONDITIONS ARE EXPECTED EXCEPT LOCAL IFR CONDITIONS IN FOG IN THE VALLEYS LATE MONDAY NIGHT AND EARLY TUESDAY. WINDS WILL BE LIGHT EASTERLY...TRANSITIONING TO LIGHT WESTERLY THIS AFTERNOON AND LIGHT SOUTHERLY TONIGHT. VICINITY OF KSFO...VFR. LIGHT OFFSHORE WINDS WINDS THIS MORNING BECOMING LIGHT VARIABLE THIS AFTERNOON. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR. LIGHT WINDS. && .MARINE...AS OF 1:49 PM PST MONDAY...EAST WINDS OVER THE COASTAL WATERS WILL TURN TO THE SOUTHEAST LATER TODAY AND TONIGHT AS WEAK LOW PRESSURE DEVELOPS OFFSHORE. HIGH PRESSURE WILL BUILD OFF THE NORTHERN CALIFORNIA COAST BY MIDWEEK...RESULTING IN LIGHT TO MODERATE NORTHWEST WINDS DURING THE SECOND HALF OF THE WEEK. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...NONE. $$ PUBLIC FORECAST: RWW AVIATION/MARINE: DYKEMA VISIT US AT WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
850 AM PST MON JAN 26 2015 .SYNOPSIS... A LOW PRESSURE SYSTEM FROM THE SOUTHWEST WILL BRING SOME LIGHT SHOWERS AND SPRINKLES THIS MORNING...WITH INCREASE SHOWERS LATE IN THE AFTERNOON AND EVENING OVER SOUTHERN CALIFORNIA. BEST RAINFALL AMOUNTS WILL LIKELY OCCUR IN THE MOUNTAINS...DESERTS AND VALLEYS. A FEW TO SEVERAL INCHES OF SNOW POSSIBLE IN THE MOUNTAINS ABOVE 7500 FOOT ELEVATION WITH THIS SYSTEM. SHOWERS DISSIPATING QUICKLY TUESDAY...WITH SLIGHTLY WARMER WEATHER AND BETTER SUNSHINE FOR WEDNESDAY. ANOTHER WEAK LOW PRESSURE SYSTEM FROM THE SOUTHWEST WILL BRING A CHANCE OF SHOWERS THURSDAY INTO THE WEEKEND. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... SOME WEAK OFFSHORE FLOW IS STILL OCCURRING THIS MORNING...WITH SOME LOCAL GUSTS IN THE 30-40 MPH RANGE. OFFSHORE PRESSURE GRADIENTS ARE CURRENTLY DOWN TO 8.2 MB FROM SAN DIEGO TO TONOPAH...WHEREAS THEY WERE 12.2 MB 24 HOURS AGO. EXPECT WEAK OFFSHORE WINDS TO CONTINUE TODAY AS THE OFFSHORE PRESSURE GRADIENT WEAKENS FURTHER...WITH SOME WARMER THAN NORMAL TEMPERATURES POSSIBLE AT THE COAST DESPITE THE INCREASED CLOUD COVER. CURRENT WATER VAPOR IMAGERY SHOWS A DEFORMATION ZONE STRETCHING FROM OFF THE COAST OF CENTRAL CALIFORNIA INTO SOUTHERN CALIFORNIA AND ARIZONA...WITH A CUT-OFF UPPER LEVEL LOW TO THE SOUTHWEST OF SAN DIEGO AND AN UPPER RIDGE TO THE NORTHEAST. IT IS EVIDENT THAT THE LOW IS SPINNING UP MOISTURE INTO THE AREA FROM THE SOUTHEAST THIS MORNING...BUT MOST OF IT IS IN THE MID AND HIGH LEVELS OF THE ATMOSPHERE. ACCORDING TO THE 12Z MIRAMAR SOUNDING...MOST OF THE MOISTURE IS ABOVE 550 MB...AND SO THE ONLY PLACES THAT HAVE REPORTED MEASURABLE RAINFALL HAVE BEEN MAINLY IN THE HIGHER ELEVATIONS OF THE MOUNTAINS DUE TO THE RAIN NOT HAVING AS MUCH TIME TO EVAPORATE IN THE DRY LOW LAYERS BEFORE REACHING THE SURFACE. THE LOW IS STILL ON TRACK TO MOVE NORTH AND WEAKEN TODAY AND THEN DEVELOP INTO AN OPEN WAVE AS IT MOVES INTO SOUTHERN CALIFORNIA TONIGHT...BEFORE MOVING OUT OF THE AREA ON TUESDAY. AS MORE MOISTURE STREAMS IN FROM THE SOUTHEAST...EVENTUALLY THE LOWER LAYERS WILL SATURATE AS WELL...RESULTING IN BETTER RAINFALL ACCUMULATIONS PARTICULARLY FOR THE LOW ELEVATIONS. RADAR IMAGERY SHOWS MOSTLY LIGHT RETURNS ASSOCIATED WITH THE AFOREMENTIONED DEFORMATION ZONE OVER THE NORTHERN PORTIONS OF THE FORECAST AREA...WITH SOME LIGHT SHOWERS/SPRINKLES MOVING UP FROM SOUTH OF THE BORDER. RAINFALL AMOUNTS FOR THE MOUNTAINS ARE EXPECTED TO RANGE FROM ONE HALF TO ONE INCH WITH LOCALLY GREATER AMOUNTS WITH ONE THIRD INCH OR LESS IN THE DESERTS AND INLAND VALLEYS WITH LESSER AMOUNTS TOWARD THE COAST. THE 13Z HRRR COMPOSITE REFLECTIVITY INITIALIZED WELL...AND ACTUALLY SHOWS THE FORECAST AREA REMAINING MOSTLY DRY THROUGH EARLY AFTERNOON BEFORE THE MAIN AREA OF PRECIPITATION MOVES INTO THE AREA FROM THE SOUTH THIS EVENING. IT IS ALSO INTERESTING TO NOTE THAT THE CANSAC WRF...LOCAL WRF AND NAM4 HAVE ALL NOTICEABLY BACKED OFF ON THE RAINFALL AMOUNTS WITH THIS SYSTEM COMPARED TO WHAT THEY SHOWED YESTERDAY. THUS...THE CURRENT POPS AND QPF MAY BE OVERDONE. THE WARM NATURE OF THE STORM WILL KEEP SNOW LEVELS HIGH...FALLING TO 7500-8000 FEET THIS EVENING...WITH A FEW TO SEVERAL INCHES OF SNOW POSSIBLE ABOVE THOSE ELEVATIONS. A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THE SAN BERNARDINO AND RIVERSIDE COUNTY MOUNTAINS ABOVE 7500 FOOT ELEVATION. FINALLY...LOOKING AT THE BUFKIT FORECAST SOUNDINGS FROM LOCAL WRF AND NAM4...DO NOT SEE MUCH IN THE WAY OF INSTABILITY. HOWEVER...WITH A VORT MAX MOVING THROUGH THIS EVENING IN COINCIDENCE WITH SOME COLD AIR ALOFT ASSOCIATED WITH THE LOW...A LIGHTNING STRIKE OR TWO AND SOME HEAVIER DOWNPOURS CANNOT BE RULED OUT...PARTICULARLY FOR THE COASTAL WATERS AND COAST. SHOWERS WILL DISSIPATE QUICKLY TUESDAY MORNING AS THE TROUGH MOVES NORTH OF THE AREA. WITH THE CONTINUED CLOUD COVER AND LOWER 850 MB TEMPERATURES...THERE SHOULD BE SOME COOLING FOR TUESDAY. SLIGHTLY WARMER WITH BETTER SUNSHINE ON WEDNESDAY WITH SOME WEAK HIGH PRESSURE ALOFT MOVING OVER THE REGION. THEN MODELS CONTINUE TO SHOW ANOTHER TROUGH MOVING INLAND OVER SOUTHERN CALIFORNIA THURSDAY AND FRIDAY...MOVING SOUTHEAST ACROSS SOUTHEAST CALIFORNIA/ARIZONA/BAJA MEXICO SATURDAY...AND THEN SOUTH INTO LOWER BAJA MEXICO ON SUNDAY. MODELS DIFFER AS TO THE AMOUNT OF MOISTURE AND PRECIPITATION...WITH THE 12Z GFS MOSTLY DRY...AND THE 00Z ECMWF SOMEWHAT WET. WITH LOW CONFIDENCE DUE TO THESE DIFFERENCES...THE SLIGHT CHANCE TO CHANCE OF SHOWERS CURRENTLY IN THE FORECAST FOR THAT TIME SEEM REASONABLE. && .AVIATION... 261630Z...BKN-OVC080-120 LOWERING TO 050-080 THIS AFTERNOON AND EVENING WITH INCREASING CHANCES FOR LIGHT SHOWERS. RAIN SHOWERS WILL BE MOST WIDESPREAD OVER THE MOUNTAINS AND DESERTS FROM 22-06Z...WITH LCL OVC040-060 IN HEAVIER SHOWERS. SHOWERS MOVING FROM SOUTH TO NORTH OVERNIGHT AND ENDING EARLY TUESDAY. && .MARINE... 830 AM...THERE IS A SLIGHT CHANCE FOR A THUNDERSTORM OVER THE COASTAL WATERS LATE THIS AFTERNOON AND EVENING. TUESDAY THROUGH FRIDAY...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH FRIDAY. && .SKYWARN... SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT PST TONIGHT ABOVE 7500 FEET FOR THE SAN BERNARDINO COUNTY MOUNTAINS. PZ...NONE. && $$ PUBLIC...HARRISON AVIATION/MARINE...MOEDE
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NWS LOS ANGELES/OXNARD CA
940 PM PST SUN JAN 25 2015 ...AVIATION DISCUSSION UPDATED... .SYNOPSIS... TWO LOW PRESSURE SYSTEMS WILL IMPACT SOUTHWESTERN CALIFORNIA THIS WEEK. THE FIRST SYSTEM WILL MOVE THROUGH THE REGION MONDAY AFTERNOON THROUGH TUESDAY WITH CHANCES OF RAIN IN ALL AREAS. THE SECOND SYSTEM IS EXPECTED THURSDAY NIGHT THROUGH SATURDAY MORNING WITH POSSIBLE PRECIPITATION FOR THE VENTURA AND LOS ANGELES COUNTY MOUNTAINS AND ANTELOPE VALLEY. OTHERWISE...VARYING AMOUNTS OF CLOUDS AND NEAR SEASONAL TEMPERATURES CAN BE EXPECTED ACROSS SOUTHWESTERN CALIFORNIA THROUGH THE WEEK. && .SHORT TERM (TODAY-WED)...EVENING UPDATE... WE SAW RECORD HEAT TODAY AT A FEW LOCATIONS INCLUDING OXNARD WITH A HIGH OF 85 BREAKING THE OLD RECORD OF 84 BACK IN 1951 FOR THIS DATE. ALSO SANTA BARBARA AP TIED THE OLD RECORD AT 79 DEGREES SET A FEW YEARS BACK IN 2012 AND 1951. LASTLY PASO ROBLES REACHED 78 DEGREES WHICH WAS A NEW RECORD BREAKING THE OLD RECORD OF 76 DEGREES SET IN 2014. AS FAR AS THE WINDS...THEY HAVE DROPPED OFF RAPIDLY EARLY THIS EVENING. THE LAX-DAG WAS STILL WEAKLY OFFSHORE BUT TRENDING NEARLY +4 MB OVER THE LAST 24 HOURS. THERE WILL BE A MAJOR WEATHER PATTERN CHANGE OVER THE NEXT 24 HOURS AS A FAIRLY EXPANSIVE UPPER LOW LOCATED AROUND 300 MILES WEST OF BAJA WILL START TO ROTATE TO THE NORTH AS THE UPPER RIDGE GETS PUSHED EASTWARD. AS USUAL...MODELS SEEM TO HAVE A TOUGH TIME HANDLING MANY DETAILS WITH ANY WET SYSTEM MOVING IN FROM THE SOUTHWEST. ALTHOUGH MOST ALL THE MODELS ARE IN PRETTY GOOD AGREEMENT BRINGING STEADY LIGHT RAIN OVER THE AREA INITIALLY LATE MONDAY AFTERNOON OR EARLY EVENING FROM THE SOUTH OVER LA COUNTY AND THEN PIVOTING NORTH TOWARDS SLO COUNTY BY MONDAY NIGHT. THE BULK OF THE RAIN WILL REMAIN ACROSS THE INTERIOR SECTIONS OF THE FORECAST AREA WHILE COASTAL AREAS COULD SEE LESS THAN A TENTH OF AN INCH. THE LATEST 00Z NAM CONCERNS ME A BIT IN RESPECT TO POSSIBLE ELEVATED THUNDERSTORMS WITH THE CENTER OF THE LOW MOVING OVER THE COASTAL WATERS MONDAY NIGHT INTO EARLY TUESDAY MORNING. 500 MB TEMPS LOWER TO AROUND -22 DEGREES C AND THERE ARE A COUPLE OF RELATIVELY STRONG VORT MAX`S MOVING OVER THE SO CAL BIGHT. ALSO...LIFTED INDEX VALUES ARE MORE IMPRESSIVE THAN WOULD THINK WITH THIS UPPER LOW. HAVE RAN SOME LOCAL FORECAST SOUNDINGS OVER THE SO CAL BIGHT AND COASTAL AREAS AND EXCEPT FOR THE LACK OF LOW LEVEL MOISTURE...THERE IS SOME ELEVATED INSTABILITY TO WORK WITH. AT THIS POINT WILL LEAVE QPF ALONE AND LET THE MID SHIFT LOOK AT LOCAL HIGH RES MODELS TO PICK UP ON SOME CONVECTIVE AREAS. ONE OTHER INTERESTING NOTE...THERE IS SOME DECENT LOW LEVEL VEERING WINDS WITH THIS UPPER LOW. SO IF A FEW STORMS DO DEVELOP OVER THE COASTAL WATERS...THE POSSIBILITY OF ISOLATED WATERSPOUTS CAN`T BE RULED OUT MONDAY NIGHT INTO TUESDAY MORNING. IN RESPECT TO THE REST OF THE FORECAST...IT LOOKS TO BE IN GREAT SHAPE FOR THE SHORT AND LONG TERM. AGAIN...WILL HAVE THE MID SHIFT LOOK AT MORE HIGH RES DATA INCLUDING RAP AND HRRR INCLUDING THE LOCAL 4KM WRF. ***FROM PREVIOUS DISCUSSION*** TONIGHT THROUGH MONDAY MORNING...THE UPPER LOW W OF BAJA WILL START TO MOVE NW ALONG THE WESTERN FRINGE OF THE UPPER RIDGE...WHILE THE UPPER RIDGE SHIFTS INTO THE WESTERN U.S. CLOUDS WILL CONTINUE TO INCREASE ON MONDAY...ALONG WITH THE CHANCE OF SHOWERS AS THE UPPER LOW STARTS TO MOVE NE TOWARDS SOCAL. POPS WERE INCREASED INTO THE LIKELY CATEGORY FOR MOST OF LA COUNTY FOR THE MONDAY EVENING TIME PERIOD...WHICH LOOKS LIKE THE BEST WINDOW FOR MEASURABLE RAIN. WITH WEAK OFFSHORE FLOW AT THE SURFACE...THE ANTELOPE VALLEY AND THE NORTH FACING SLOPES OF THE SAN GABRIEL MOUNTAINS WILL LIKELY HAVE THE HIGHEST RAINFALL AMOUNTS. EXPECTING 0.25"-0.50" OF RAIN IN THESE AREAS...WITH LIGHTER AMOUNTS W OF THE MOUNTAINS. ANY RAIN SHOWERS SHOULD BE PRETTY MUCH DONE BY TUESDAY MORNING AS THE UPPER LOW WEAKENS AND MOVES N. NOT MUCH SNOW EXPECTED WITH THIS SYSTEM...AS SNOW LEVELS WILL GENERALLY REMAIN ABOVE 7000 FT...WITH LIGHT ACCUMULATIONS POSSIBLE ABOVE THAT ALTITUDE. NO T-STORMS IN THE FORECAST AS THEIR WILL BE LITTLE INSTABILITY TO WORK WITH (LESS THAN 500 J/KG OF CAPE OVER THE COASTAL WATERS) AND LIFT ASSOCIATED WITH THE UPPER LOW WILL BE RELATIVELY WEAK. HOWEVER...WOULDN`T BE TOTALLY SURPRISED IF THERE IS A T-STORM OR TWO WELL OFF THE COAST ON MONDAY EVENING. MAX TEMPS ON MONDAY AND TUESDAY WILL BE MUCH COOLER THAN THEY WERE OVER THE WEEKEND...WITH NEAR NORMAL HIGHS EXPECTED. WEDNESDAY WILL BE SEVERAL DEGREES WARMER AS A WEAK RIDGE POPS UP AHEAD OF THE NEXT TROF OF LOW PRESSURE. WEAK OFFSHORE GRADIENTS AND FEWER CLOUDS WILL HELP WITH THE WARMING ON WEDNESDAY AS WELL. .LONG TERM (THU-SUN)... LATEST MODELS ARE IN FAIRLY GOOD SYNOPTIC AGREEMENT THROUGH NEXT WEEKEND...BUT WE WILL BE DEALING WITH ANOTHER CUTOFF LOW FRIDAY THROUGH SUNDAY...SO WE`LL SEE HOW THAT GOES. CURRENT FORECAST HAS A SLIGHT CHANCE OF SHOWERS FOR THE VENTURA/LA MOUNTAINS AND THE ANTELOPE VALLEY THURSDAY THROUGH SATURDAY. FORECAST CONFIDENCE IS RELATIVELY LOW...BUT NOT EXPECTING THIS TO BE A MAJOR RAIN PRODUCER AT THIS TIME. CURRENT FORECAST ALSO HAS NEAR NORMAL TEMPS FOR THURSDAY AND FRIDAY...WITH THE UPPER-LEVEL TROUGH OVERHEAD. SLIGHT WARMING TREND FORECASTED FOR NEXT WEEKEND AS THE UPPER LOW DRIFTS TO THE SE AND RIDGING/OFFSHORE FLOW DEVELOPS. && .AVIATION...26/06Z... AT 0520Z AT KLAX... THERE WAS NO INVERSION. OVERALL...MODERATE CONFIDENCE IN 06Z TAFS. REDUCED CONFIDENCE DUE TO UNCERTAINTY IN THE TIMING AND INTENSITY OF THE INCOMING PRECIPITATION AND THE EFFECT ON WIND FLOW AND VSBY. AN INCREASING CHANCE OF PRECIPITATION ACROSS THE REGION BEGINNING IN LOS ANGELES COUNTY 22Z-00Z AND MOVING NORTH TOWARD SAN LUIS OBISPO COUNTY BY 06Z. CONDITIONS ARE MOST LIKELY TO REMAIN VFR THROUGH THE FORECAST PERIOD THOUGH THERE IS A THIRTY PERCENT CHANCE OF MVFR CONDITIONS AFTER 23Z. KLAX...MODERATE CONFIDENCE IN 06Z TAF. REDUCED CONFIDENCE DUE TO UNCERTAINTY IN THE TIMING AND INTENSITY OF THE INCOMING PRECIPITATION AND THE EFFECT ON WIND FLOW AND VSBY. AN INCREASING CHANCE OF PRECIPITATION BEGINNING 22Z-00Z. CONDITIONS ARE MOST LIKELY TO REMAIN VFR THROUGH THE FORECAST PERIOD THOUGH THERE IS A THIRTY PERCENT CHANCE OF MVFR CONDITIONS AFTER 23Z. A THIRTY PERCENT CHANCE OF SOUTHEAST TO EAST WINDS GREATER THAN 7 KTS 09Z-18Z. KBUR...MODERATE CONFIDENCE IN 06Z TAF. REDUCED CONFIDENCE DUE TO UNCERTAINTY IN THE TIMING AND INTENSITY OF THE INCOMING PRECIPITATION AND THE EFFECT ON WIND FLOW AND VSBY. AN INCREASING CHANCE OF PRECIPITATION BEGINNING 22Z-00Z. CONDITIONS ARE MOST LIKELY TO REMAIN VFR THROUGH THE FORECAST PERIOD THOUGH THERE IS A THIRTY PERCENT CHANCE OF MVFR CONDITIONS AFTER 23Z. .MARINE...25/745 PM... AN AREA OF LOW PRESSURE OFF OF CENTRAL BAJA WILL MOVE NORTH OVER THE AREA AND SOUTH AND SOUTHEAST WIND GUST TO AROUND 25 KT ARE EXPECTED MONDAY MORNING AND PERSIST THROUGH THE AFTERNOON. THE STRONGEST WINDS ARE EXPECTED OVER THE SANTA BARBARA CHANNEL AND SANTA MONICA BASIN. OTHERWISE...THERE IS A CHANCE FOR SMALL CRAFT ADVISORY CONDITIONS OVER THE OUTER WATERS THRU THRU FRI AS NORTH WINDS DEVELOP AND THEN STRENGTHEN. && .LOX WATCHES/WARNINGS/ADVISORIES... HIGH RIP CURRENT RISK (SEE LAXSRFLOX). && $$ PUBLIC...KAPLAN/SUKUP AVIATION...KJ MARINE...SIRARD SYNOPSIS...SIRARD WWW.WEATHER.GOV/LOSANGELES
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATE
NWS LOS ANGELES/OXNARD CA
810 PM PST SUN JAN 25 2015 .SYNOPSIS... TWO LOW PRESSURE SYSTEMS WILL IMPACT SOUTHWESTERN CALIFORNIA THIS WEEK. THE FIRST SYSTEM WILL MOVE THROUGH THE REGION MONDAY AFTERNOON THROUGH TUESDAY WITH CHANCES OF RAIN IN ALL AREAS. THE SECOND SYSTEM IS EXPECTED THURSDAY NIGHT THROUGH SATURDAY MORNING WITH POSSIBLE PRECIPITATION FOR THE VENTURA AND LOS ANGELES COUNTY MOUNTAINS AND ANTELOPE VALLEY. OTHERWISE...VARYING AMOUNTS OF CLOUDS AND NEAR SEASONAL TEMPERATURES CAN BE EXPECTED ACROSS SOUTHWESTERN CALIFORNIA THROUGH THE WEEK. && .SHORT TERM (TODAY-WED)...EVENING UPDATE... WE SAW RECORD HEAT TODAY AT A FEW LOCATIONS INCLUDING OXNARD WITH A HIGH OF 85 BREAKING THE OLD RECORD OF 84 BACK IN 1951 FOR THIS DATE. ALSO SANTA BARBARA AP TIED THE OLD RECORD AT 79 DEGREES SET A FEW YEARS BACK IN 2012 AND 1951. LASTLY PASO ROBLES REACHED 78 DEGREES WHICH WAS A NEW RECORD BREAKING THE OLD RECORD OF 76 DEGREES SET IN 2014. AS FAR AS THE WINDS...THEY HAVE DROPPED OFF RAPIDLY EARLY THIS EVENING. THE LAX-DAG WAS STILL WEAKLY OFFSHORE BUT TRENDING NEARLY +4 MB OVER THE LAST 24 HOURS. THERE WILL BE A MAJOR WEATHER PATTERN CHANGE OVER THE NEXT 24 HOURS AS A FAIRLY EXPANSIVE UPPER LOW LOCATED AROUND 300 MILES WEST OF BAJA WILL START TO ROTATE TO THE NORTH AS THE UPPER RIDGE GETS PUSHED EASTWARD. AS USUAL...MODELS SEEM TO HAVE A TOUGH TIME HANDLING MANY DETAILS WITH ANY WET SYSTEM MOVING IN FROM THE SOUTHWEST. ALTHOUGH MOST ALL THE MODELS ARE IN PRETTY GOOD AGREEMENT BRINGING STEADY LIGHT RAIN OVER THE AREA INITIALLY LATE MONDAY AFTERNOON OR EARLY EVENING FROM THE SOUTH OVER LA COUNTY AND THEN PIVOTING NORTH TOWARDS SLO COUNTY BY MONDAY NIGHT. THE BULK OF THE RAIN WILL REMAIN ACROSS THE INTERIOR SECTIONS OF THE FORECAST AREA WHILE COASTAL AREAS COULD SEE LESS THAN A TENTH OF AN INCH. THE LATEST 00Z NAM CONCERNS ME A BIT IN RESPECT TO POSSIBLE ELEVATED THUNDERSTORMS WITH THE CENTER OF THE LOW MOVING OVER THE COASTAL WATERS MONDAY NIGHT INTO EARLY TUESDAY MORNING. 500 MB TEMPS LOWER TO AROUND -22 DEGREES C AND THERE ARE A COUPLE OF RELATIVELY STRONG VORT MAX`S MOVING OVER THE SO CAL BIGHT. ALSO...LIFTED INDEX VALUES ARE MORE IMPRESSIVE THAN WOULD THINK WITH THIS UPPER LOW. HAVE RAN SOME LOCAL FORECAST SOUNDINGS OVER THE SO CAL BIGHT AND COASTAL AREAS AND EXCEPT FOR THE LACK OF LOW LEVEL MOISTURE...THERE IS SOME ELEVATED INSTABILITY TO WORK WITH. AT THIS POINT WILL LEAVE QPF ALONE AND LET THE MID SHIFT LOOK AT LOCAL HIGH RES MODELS TO PICK UP ON SOME CONVECTIVE AREAS. ONE OTHER INTERESTING NOTE...THERE IS SOME DECENT LOW LEVEL VEERING WINDS WITH THIS UPPER LOW. SO IF A FEW STORMS DO DEVELOP OVER THE COASTAL WATERS...THE POSSIBILITY OF ISOLATED WATERSPOUTS CAN`T BE RULED OUT MONDAY NIGHT INTO TUESDAY MORNING. IN RESPECT TO THE REST OF THE FORECAST...IT LOOKS TO BE IN GREAT SHAPE FOR THE SHORT AND LONG TERM. AGAIN...WILL HAVE THE MID SHIFT LOOK AT MORE HIGH RES DATA INCLUDING RAP AND HRRR INCLUDING THE LOCAL 4KM WRF. ***FROM PREVIOUS DISCUSSION*** TONIGHT THROUGH MONDAY MORNING...THE UPPER LOW W OF BAJA WILL START TO MOVE NW ALONG THE WESTERN FRINGE OF THE UPPER RIDGE...WHILE THE UPPER RIDGE SHIFTS INTO THE WESTERN U.S. CLOUDS WILL CONTINUE TO INCREASE ON MONDAY...ALONG WITH THE CHANCE OF SHOWERS AS THE UPPER LOW STARTS TO MOVE NE TOWARDS SOCAL. POPS WERE INCREASED INTO THE LIKELY CATEGORY FOR MOST OF LA COUNTY FOR THE MONDAY EVENING TIME PERIOD...WHICH LOOKS LIKE THE BEST WINDOW FOR MEASURABLE RAIN. WITH WEAK OFFSHORE FLOW AT THE SURFACE...THE ANTELOPE VALLEY AND THE NORTH FACING SLOPES OF THE SAN GABRIEL MOUNTAINS WILL LIKELY HAVE THE HIGHEST RAINFALL AMOUNTS. EXPECTING 0.25"-0.50" OF RAIN IN THESE AREAS...WITH LIGHTER AMOUNTS W OF THE MOUNTAINS. ANY RAIN SHOWERS SHOULD BE PRETTY MUCH DONE BY TUESDAY MORNING AS THE UPPER LOW WEAKENS AND MOVES N. NOT MUCH SNOW EXPECTED WITH THIS SYSTEM...AS SNOW LEVELS WILL GENERALLY REMAIN ABOVE 7000 FT...WITH LIGHT ACCUMULATIONS POSSIBLE ABOVE THAT ALTITUDE. NO T-STORMS IN THE FORECAST AS THEIR WILL BE LITTLE INSTABILITY TO WORK WITH (LESS THAN 500 J/KG OF CAPE OVER THE COASTAL WATERS) AND LIFT ASSOCIATED WITH THE UPPER LOW WILL BE RELATIVELY WEAK. HOWEVER...WOULDN`T BE TOTALLY SURPRISED IF THERE IS A T-STORM OR TWO WELL OFF THE COAST ON MONDAY EVENING. MAX TEMPS ON MONDAY AND TUESDAY WILL BE MUCH COOLER THAN THEY WERE OVER THE WEEKEND...WITH NEAR NORMAL HIGHS EXPECTED. WEDNESDAY WILL BE SEVERAL DEGREES WARMER AS A WEAK RIDGE POPS UP AHEAD OF THE NEXT TROF OF LOW PRESSURE. WEAK OFFSHORE GRADIENTS AND FEWER CLOUDS WILL HELP WITH THE WARMING ON WEDNESDAY AS WELL. .LONG TERM (THU-SUN)... LATEST MODELS ARE IN FAIRLY GOOD SYNOPTIC AGREEMENT THROUGH NEXT WEEKEND...BUT WE WILL BE DEALING WITH ANOTHER CUTOFF LOW FRIDAY THROUGH SUNDAY...SO WE`LL SEE HOW THAT GOES. CURRENT FORECAST HAS A SLIGHT CHANCE OF SHOWERS FOR THE VENTURA/LA MOUNTAINS AND THE ANTELOPE VALLEY THURSDAY THROUGH SATURDAY. FORECAST CONFIDENCE IS RELATIVELY LOW...BUT NOT EXPECTING THIS TO BE A MAJOR RAIN PRODUCER AT THIS TIME. CURRENT FORECAST ALSO HAS NEAR NORMAL TEMPS FOR THURSDAY AND FRIDAY...WITH THE UPPER-LEVEL TROUGH OVERHEAD. SLIGHT WARMING TREND FORECASTED FOR NEXT WEEKEND AS THE UPPER LOW DRIFTS TO THE SE AND RIDGING/OFFSHORE FLOW DEVELOPS. && .AVIATION...26/0050Z... AT 0030Z THERE WAS NO INVERSION AT KLAX. MODERATE CONFIDENCE WITH 00Z TAFS. OVERALL EXPECT INCREASING VFR CLOUD CONDS OVER THE NEXT 24 HOURS ACROSS THE ENTIRE FORECAST AREA. THERE WILL BE A 30 PERCENT CHANCE FOR MVFR CIGS AFTER 19Z FOR LOS ANGELES COUNTY. EXPECT INCREASING CHANCE FOR SHOWERS BY MONDAY NIGHT INITIALLY FROM LOS ANGELES COUNTY...THEN WORKING NORTH INTO SAN LUIS OBISPO COUNTY MONDAY NIGHT. KLAX...MODERATE TO HIGH CONFIDENCE WITH 00Z TAF. EXPECT VFR CLOUD COVER OVER NEXT 24 HOURS. 30 PERCENT CHANCE FOR MVFR CIGS TO DEVELOP AFTER 19Z. 20 PERCENT CHANCE FOR 50 PERCENT CHANCE FOR -RA BY 23Z MONDAY. 30 PERCENT THAT SE-E WIND DIRECTION WILL BE OVER 7 KTS BETWEEN 09Z-18Z. KBUR...MODERATE TO HIGH CONFIDENCE WITH 00Z TAF. EXPECT VFR CLOUD COVER OVER NEXT 24 HOURS. 30 PERCENT CHANCE FOR MVFR CIGS TO DEVELOP AFTER 19Z. 20 PERCENT CHANCE FOR 50 PERCENT CHANCE FOR -RA BY 23Z MONDAY. NOT ANTICIPATING ANY WIND ISSUES OVER NEXT 24 HOURS. .MARINE...25/745 PM... AN AREA OF LOW PRESSURE OFF OF CENTRAL BAJA WILL MOVE NORTH OVER THE AREA AND SOUTH AND SOUTHEAST WIND GUST TO AROUND 25 KT ARE EXPECTED MONDAY MORNING AND PERSIST THROUGH THE AFTERNOON. THE STRONGEST WINDS ARE EXPECTED OVER THE SANTA BARBARA CHANNEL AND SANTA MONICA BASIN. OTHERWISE...THERE IS A CHANCE FOR SMALL CRAFT ADVISORY CONDITIONS OVER THE OUTER WATERS THRU THRU FRI AS NORTH WINDS DEVELOP AND THEN STRENGTHEN. && .LOX WATCHES/WARNINGS/ADVISORIES... HIGH RIP CURRENT RISK (SEE LAXSRFLOX). && $$ PUBLIC...KAPLAN/SUKUP AVIATION...KAPLAN MARINE...SIRARD SYNOPSIS...SIRARD WWW.WEATHER.GOV/LOSANGELES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
912 PM CST TUE JAN 27 2015 .UPDATE... 905 PM CST LOW CLOUD COVER CONTINUES TO SLOWLY MOVE WESTWARD AND HAS CLEARED ALL BUT THE WESTERN FRINGES OF THE FORECAST AREA THIS EVENING. SATELLITE SHOWS SOME HIGHER CLOUD STREAKS APPROACHING FROM THE NORTHWEST AS UPPER RIDGING SHIFTS EASTWARD BUT COVERAGE LOOKS LOOKS TO BE SPORADIC THROUGH THE NIGHT AND MAY BE AT A MINIMUM DURING THE EARLY OVERNIGHT. TEMPERATURES HAVE BEGUN TO DROP OFF WHERE THANKS TO THE MAINLY CLEAR SKIES WITH SEVERAL SITES IN NORTH-CENTRAL ILLINOIS NOW IN THE TEENS. GIVEN THAT HIGHER CLOUD COVER LOOKS INTERMITTENT AND WINDS WILL DROP OFF WITH HIGH PRESSURE MOVING OVERHEAD HAVE GONE AHEAD AND LOWERED MINS OVERNIGHT FOR MOST AREAS...THOUGH WESTERN FRINGES MAY SEE LOWER LEVEL CLOUD COVER LINGER THROUGH THE NIGHT. WILL GO WITH LOWER TEENS FOR MUCH OF THE WESTERN/CENTRAL CWA AND SOME OF THE TRADITIONALLY COLDER SPOTS FROM LEE/OGLE COUNTIES TO DEKALB AND KANE COUNTIES COULD SEE VALUES A LITTLE BIT LOWER IF HIGH CLOUD COVER REMAINS VERY MINIMAL. WITH THE LOWER TEMPS AND SPORADIC HIGHER CLOUD COVER...FREEZING FOG WILL BE A CONCERN. THE COLDEST AREAS WILL LIKELY SEE A QUICK DROP OFF IN THE NEXT FEW HOURS WHICH MAY LEAD TO MORE FROST DEPOSITION RATHER THAN FOG FORMATION. WITH LIMITED CONFIDENCE IN THIS HAPPENING AND REASONABLE SUPPORT FOR SOME FOG DEVELOPMENT...WILL GO AHEAD AND ADD PATCHY FOG TO MUCH OF THE CENTRAL AND WESTERN CWA OR FROM THE FAR WESTERN CHICAGO METRO WEST AND SOUTHWEST FOR NOW. THIS MAY CAUSE SOME SLICK SPOTS ON ROADS OVERNIGHT. MDB && .SHORT TERM... 304 PM CST THROUGH THURSDAY... PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND THE STRATUS DECK CURRENTLY OVER THE SOUTHWESTERN 2/3RDS OF THE CWA. WOULD ANTICIPATE A CONTINUED VERY SLOW CLEARING FROM THE EAST FOR A COUPLE MORE HOURS BEFORE LOW LEVEL FLOW DIMINISHES THIS EVENING BEFORE BACKING TO SOUTHERLY OVERNIGHT...WHICH MAY WELL SEND STRATUS SLOSHING BACK NORTH INTO AREAS THAT HAD PREVIOUSLY CLEARED OUT. TRIED TO REFLECT A TREND LIKE THIS IN THE HOURLY SKY GRIDS AND RESULTANT TEMPERATURE GRIDS...BUT GIVEN THE POOR MODEL HANDLING OF THIS CLOUDINESS IT PRETTY MUCH GUARANTEED THAT OUR CURRENT SKY GRIDS WILL BE WRONG SOMEWHERE AND NEED UPDATING WITH ACCOMPANYING CHANGES NEEDED IN TEMPS TONIGHT. WHERE SKIES BECOME/STAY CLEAR TONIGHT COULD SEE FREEZING GROUND FOG DEVELOP GIVEN THE LIGHT WINDS...BUT WILL LET EVENING SHIFT WATCH TRENDS AND ADD FREEZING FOG AS NEEDED. FOR WEDNESDAY HAVE OPTED TO BE OPTIMISTIC IN PUSHING STRATUS NORTH AND BREAKING IT UP IN THE MORNING BUT THIS VERY WELL MAY END UP BEING TOO OPTIMISTIC. ASSUMING THERE IS SOME SUNSHINE TOMORROW PRIOR TO THE ARRIVAL OF EXTENSIVE MID AND HIGH LEVEL CLOUDINESS THEN HIGHS COULD PUSH WELL INTO THE 30S...PARTICULARLY IN THE LESS SNOW COVERED AND MORE URBANIZED AREAS. DEVELOPING LOW PRESSURE TO OUR WEST SHOULD RESULT IN TIGHTENING PRESSURE GRADIENT AND STRENGTHENING SOUTHERLY WINDS WEDNESDAY. IZZI && .LONG TERM... 304 PM CST THURSDAY NIGHT THROUGH TUESDAY... BRISK SOUTH WINDS...WARM AIR ADVECTION...AND CLOUD COVER IN ADVANCE OF THE SYSTEM WEDNESDAY NIGHT SHOULD RESULT IN NEARLY STEADY TEMPS IN THE EVENING AND PROBABLY RISING A BIT OVERNIGHT. COULD SEE A BIT OF LIGHT RAIN OR DRIZZLE IN THE WARM SECTOR WEDNESDAY NIGHT FOLLOWED BY SOME POTENTIAL FOR A BIT OF WRAP AROUND RAIN OR SNOW SHOWERS THURSDAY ON THE BACK SIDE OF THE SYSTEM. STILL LOOKS LIKE PRETTY LIMITED MOISTURE WITH THE SYSTEM AND HIGHEST QPF FOCUSED TO OUR NORTH WITH LIGHT AMOUNTS IN OUR CWA AND ONLY MINIMAL THREAT OF ANY ACCUMULATED FROZEN/FREEZING PRECIP GIVEN THE FORECAST TRACK AND TEMPS. SHOT OF SEASONABLY COLD AIR WILL KNOCK TEMPS TO JUST A HAIR BELOW AVERAGE FRIDAY. VIGOROUS ALBERTA CLIPPER IS FORECAST TO RESULT IN AN AMPLIFYING LONG WAVE TROUGH OVER THE CENTRAL CONUS THIS WEEKEND. STILL SOME LARGE SPREAD BETWEEN MODELS WITH RESPECT TO THE DETAILS THIS WEEKEND...BUT THERE HAS BEEN SOME AGREEMENT THE PAST COUPLE DAYS ON THE GENERAL IDEA OF A LARGE SWATH OF ACCUMULATING SNOW POTENTIALLY AFFECTING THE REGION SAT NIGHT INTO SUNDAY. ARCTIC AIR IS FORECAST TO SURGE SOUTH INTO THE AREA IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK...BUT THE DURATION AND MAGNITUDE OF THIS ARCTIC INTRUSION ARE DEPENDENT ON WHICH MODEL YOU LOOK AT MEANING FAIRLY LOW FORECAST CONFIDENCE AT THIS POINT. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * GUSTY SSELY WINDS TOMORROW. * CHANCE FOR MVFR CIGS OR VIS LATE TONIGHT. KREIN //DISCUSSION...UPDATED 00Z... THE DECK OF MVFR STRATOCU CONTINUES TO ERODE FROM EAST TO WEST PER LATEST SATELLITE IMAGERY. RFD REMAINS THE ONLY TAF SITE STILL WITH MVFR CIGS AND IS JUST WEST OF THE EDGE OF THE CLEARING SKIES. THE EDGE OF THE CLEARING APPEARS TO HAVE SLOWED WITH THE SETTING SUN...SO HAVE DELAYED IMPROVEMENT OF CIGS THERE UNTIL 04Z...BUT THE CONFIDENCE IN THE EXACT TIMING IS LOW. AS HIGH PRESSURE SETTLES OVER THE AREA TONIGHT...WINDS WILL DROP OFF TO LGT/VRBL...AND WITH THE DECREASING CLOUD COVER...THERE SHOULD BE ENOUGH RADIATIVE COOLING FOR TEMPERATURES TO DROP LOW ENOUGH OVER RURAL AREAS TO ALLOW FOR SOME AREA OF BR DEVELOPMENT WITH VIS DROPPING INTO THE 3-5SM RANGE. ORD/MDW/GYY WILL LIKELY REMAIN VFR DUE TO URBAN HEAT ISLAND EFFECTS PREVENTING TEMPERATURES FROM DROPPING OFF AS MUCH. THE MAIN CONCERN FOR TOMORROW WILL BE WINDS. AS THE HIGH SETTLES TO THE SOUTH AND LOW PRESSURE TRACKS EWD ACROSS THE CNTRL PLAINS...A STRENGTHENING SOUTHERLY GRADIENT WILL SET UP...WITH WINDS INCREASING BY LATE MORNING. THERE SHOULD BE ADEQUATE SUNSHINE TO ALLOW FOR STRONGER WINDS ABOVE THE SFC TO MIX DOWN...WITH GUSTS IN THE 20-25KT RANGE LIKELY THROUGH THE AFTERNOON. THE LOW PRESSURE SYSTEM TRACKING ACROSS THE PLAINS SHOULD BRING THE NEXT CHANCE FOR PCPN AND REDUCED CIGS/VIS...BUT THIS WILL LIKELY NOT BE UNTIL AFTER MIDNIGHT TOMORROW NIGHT. KREIN //ORD AND MDW CONFIDENCE...UPDATED 03Z... * MEDIUM CONFIDENCE IN CIGS/VIS TRENDS. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...CHANCE OF RAIN/SNOW. MVFR LIKELY/IFR POSSIBLE. FRIDAY...VFR. WX NIL. SATURDAY...CHANCE OF SNOW IN THE AFTERNOON AND OVERNIGHT. VFR EARLY THEN MVFR LIKELY/IFR POSSIBLE. SUNDAY...CHANCE OF SNOW. IFR POSSIBLE. MONDAY...VFR. WX NIL. KREIN && .MARINE... 318 PM CST LIGHTER NORTHERLY WINDS IN PLACE THIS AFTERNOON AS HIGH PRESSURE SPANS THE REGION...WILL FURTHER DIMINISH THIS EVENING AS THIS HIGH MOVES OVERHEAD. THIS HIGH WILL THEN CONTINUE SOUTHEAST TOWARDS THE OHIO VALLEY TONIGHT AS A TROUGH OF LOW PRESSURE MOVES EAST ACROSS THE CENTRAL PLAINS. THIS WILL HELP THE WINDS TO TURN BACK MORE SOUTHERLY AND THEN BEGIN TO SLOWLY INCREASE LATER TONIGHT INTO WEDNESDAY. THIS INCREASING TREND WILL CONTINUE THROUGHOUT THE DAY WEDNESDAY...WITH SOUTHERLY WINDS REALLY INCREASING DURING THE AFTERNOON TIME FRAME. THIS WILL LIKELY CREATE WINDS HAZARDOUS FOR SMALL CRAFT...AND SO HAVE ISSUED A SMALL CRAFT ADVISORY FOR WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY NIGHT WHEN WINDS WILL DIMINISH WITH THE APPROACHING LOW PRESSURE. THIS WILL LIKELY BE BRIEF AS WINDS WILL QUICKLY INCREASE ONCE AGAIN ON THE BACKSIDE OF THIS SYSTEM THURSDAY. ALSO...SOUTHERLY WINDS ACROSS THE SOUTHERN HALF OF THE LAKE COULD HOVER AROUND 30 KT A FOR A BRIEF WINDOW WEDNESDAY NIGHT. WILL NEED TO MONITOR TRENDS DURING THIS PERIOD...BUT WILL MAKE MENTION OF OCCASIONAL GALE FORCE GUSTS DURING THIS TIME. EXPECT STRONG WINDS TO BE IN PLACE ON THURSDAY...REALLY INCREASING INTO THE AFTERNOON AND EVENING HOURS. GALES ARE APPEARING LIKELY FOR THE ENTIRE LAKE DURING THIS TIME...EVEN FOR THE NEARSHORE WATERS...BUT WITH SPEEDS DIMINISHING ONCE AGAIN LATE THURSDAY NIGHT INTO FRIDAY. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...NOON WEDNESDAY TO 4 AM THURSDAY. && $$ 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 639 PM CST Tue Jan 27 2015 .UPDATE... ISSUED AT 639 PM CST TUE JAN 27 2015 Made some quick updates to the forecast this evening, mainly to better reflect current and expected sky trends. 00z/6pm IR satellite imagery shows cloud cover steadily eroding from the E/NE, with mostly clear skies currently noted along/northeast of a Champaign to Paris line. Clouds are beginning to break up south of there along/south of the I-70 corridor as well. Based on satellite loops and the latest HRRR forecast, it appears skies will become partly to mostly clear across much of the KILX CWA tonight, except perhaps the far NW around Galesburg. Will continue to monitor trends to see if additional updates are needed, but for now will hold on to overcast conditions through the entire night northwest of the Peoria area with clearing skies elsewhere. Low temperatures will be coldest where clearing has already occurred across the NE CWA around Danville, where readings will dip into the teens. Lower to middle 20s seem reasonable across the rest of central Illinois. && .SHORT TERM...(Through Wednesday afternoon) ISSUED AT 255 PM CST TUE JAN 27 2015 MAIN CHALLENGE IN THE SHORT/NEAR TERM REVOLVES AROUND CLOUD COVER TONIGHT...WINDS AND TEMPS ON WEDNESDAY. A SURFACE RIDGE IS IN PLACE OVERHEAD...AND SATELLITE PICTURES SHOW LOWER CLOUDS ERODING FROM THE NORTHEAST THIS AFTERNOON AS DRIER AIR FILTERS IN. BEST CHANCES FOR EROSION WILL BE FOR EASTERN AREAS WHERE THIS DRIER AIR IS MAKING BETTER HEADWAY. RAW MODEL GUIDANCE CONTINUES TO ADVERTISE CLEARING MUCH SOONER THIS EVENING AREA-WIDE...WHILE RAP TIME HEIGHTS SUGGEST IT WILL TAKE UNTIL LATER TONIGHT FOR THIS TO OCCUR...ESPECIALLY NORTH OF I-72. MODEL SOUNDINGS SUGGEST THAT THIS LOWER LEVEL MOISTURE WILL REMAIN TRAPPED BELOW A SUBSIDENCE INVERSION...AND THAT IT WILL AT LEAST HOLD FIRM THROUGH THE EVENING HOURS. CLOUD BEARING WINDS WILL BE TURNING MORE NORTHERLY AS WELL...WHICH WOULD SUPPORT CLOUDS HANGING ON ALONG AND WEST OF HIGHWAY 51. SURFACE HIGH PRESSURE TONIGHT WILL SHIFT OFF THE EAST TONIGHT AS THE UPPER RIDGE IN THE PLAINS MOVE EAST AND CONTINUES TO DEAMPLIFY. EXPECT WINDS TO SHIFT TO THE SE OVERNIGHT...WITH LOWS IN THE EAST IN THE UPPER TEENS TO NEAR 20...WITH 20S HOLDING WEST WHERE CLOUD COVER IS EXPECTED TO BE MORE PREVALENT. THURSDAY...ATTENTION SHIFTS TO UPPER LEVEL LOW PRESSURE MOVING THROUGH THE GREAT BASIN THIS AFTERNOON. THE UPPER TROUGH MOVES INTO THE PLAINS RIDGE WHILE ADDITIONAL PACIFIC ENERGY MOVES INTO THE NORTHERN PLAINS. LOW LEVEL WARM ADVECTION ENSUES IN THE SOUTHWESTERLY FLOW AHEAD OF THESE SYSTEM .IT APPEARS THAT NOT ALL OF OF THIS LOW LEVEL WARMING WILL NOT TRANSLATE TO THE SURFACE WITH A FAIRLY STRONG INVERSION HOLDING...BUT DO EXPECT SOME WARMING FROM TODAY`S READINGS...ESPECIALLY FOR SOUTHERN AND WESTERN AREAS WHERE MID 40S LOOK LIKE A DECENT BET. AREAS NORTH AND EAST WILL REMAIN ON THE COOLER SIDE STRUGGLING TO REACH 40. AHEAD OF THESE TWO DISTURBANCES SURFACE LOW PRESSURE OF 1005 MB COMBINES WITH THE DEPARTING HIGH TO CREATE A MODEST PRESSURE GRADIENT ACROSS THE AREA. A VERY STRONG LOW LEVEL JET SETS UP LATE IN THE AFTERNOON...BUT GIVEN THE LOW LEVEL INVERSION...EXPECT A BREEZY DAY WITH GUSTS IN THE 25 KT RANGE. KMD && .LONG TERM...(Wednesday Night through Tuesday) ISSUED AT 340 PM CST TUE JAN 27 2015 WEDNESDAY NIGHT THROUGH SATURDAY... A WINDY AND MILD NIGHT IS IN STORE ON WEDNESDAY NIGHT AS LOW PRESSURE QUICKLY MOVES JUST NORTH OF THE CWA. STRONG PRESSURE FALLS DUE TO TIGHTENING GRADIENT BETWEEN ADVANCING LOW AND DEPARTING HIGH PRESSURE TO THE EAST WILL RESULT IN SUSTAINED SOUTHERLY WINDS IN THE MID TO HIGH TEENS WITH GUSTS OF 20-25 KT. TEMPERATURES SHOULD DROP SOME IN THE EVENING BUT THEN ARE LIKELY TO SLOWLY RISE TOWARD DAYBREAK. THERE IS A DECENT VORT MAX ASSOCIATED WITH APPROACHING SHORT WAVE TROUGH...BUT GUIDANCE IS FAIRLY DRY WITH EXCEPTION OF ECMWF AND NAM. MAINTAINED SLIGHT TO LOW END CHANCE POPS FOR LIGHT RAIN MAINLY AFTER MIDNIGHT. MAY NEED TO ADD DRIZZLE TO GRIDS. COLD FRONT TRAILING FROM THE LOW PRESSURE WILL SWEEP ACROSS THE AREA FROM NW TO SE OVERNIGHT INTO THURSDAY MORNING...SHIFTING WINDS FROM SOUTHWEST TO NORTHWEST...AND COLD ADVECTION RAMPING UP BEHIND IT. HAVE LOW POPS FOR MOST OF THE CWA IN THE MORNING...BUT ANY PRECIP WOULD LIKELY BE LIGHT RAIN DESPITE COLD ADVECTION AS SURFACE TEMPERATURES WOULDNT COOL QUICK ENOUGH FROM EARLY HIGHS IN THE UPPER 30S TO MID 40S...WARMEST FAR SOUTHEAST. BIGGER STORY WILL BE STRONG ISALLOBARIC PRESSURE RISES BEHIND FRONT RESULTING IN NORTHWEST WINDS GUSTING TO 30-35 MPH MUCH OF THE MORNING AND AFTERNOON. WINDS WILL GRADUALLY DIMINISH THURSDAY NIGHT AS EXPANSIVE HIGH PRESSURE SPREADS SOUTHEAST. EXPECT LOWS IN THE UPPER TEENS TO MID 20S BY EARLY FRIDAY...RECOVERING TO SLIGHTLY BELOW CLIMO LOW-MID 30S UNDER LARGE CANADIAN HIGH. THE HIGH WILL SLIDE SOUTHEAST ON SATURDAY...ALLOWING TEMPS TO WARM SLIGHTLY TO THE MID TO UPPER 30S. SATURDAY NIGHT THROUGH TUESDAY... ATTENTION TURNS TO EJECTION OF CLOSED UPPER LOW OVER THE DESERT SOUTHWEST AS MORE OF AN OPEN WAVE SATURDAY NIGHT INTO SUNDAY...WITH ASSOCIATED WEAK SURFACE LOW POSSIBLY MOVING TOWARD THE LOWER OR MID MS VALLEY THEN OH VALLEY BY SUNDAY EVENING. WITH IT BEING STILL OVER 100 HRS OUT...GUIDANCE VARIES ON PLACEMENT OF SURFACE LOW...BUT DECENT AGREEMENT IN OPERATIONAL MODELS AND ENSEMBLES OF BROAD WARM ADVECTION/ISENTROPIC ASCENT WITH THIS SYSTEM. THIS YIELDS THE POTENTIAL FOR FAIRLY LONG DURATION PRECIPITATION. AT THIS POINT...THERMAL PROFILES APPEAR COLD ENOUGH FOR SNOW ACROSS THE CWA...BUT FARTHER NORTHWEST/STRONGER LOW COULD INTRODUCE P-TYPE CONCERNS...ESPECIALLY IN THE FAR SOUTHEAST. WAY TOO EARLY TO DISCUSS POTENTIAL SNOW ACCUMULATIONS...BUT THIS PERIOD BEARS WATCHING. BEHIND THIS SYSTEM...MODELS HAVE BEEN WAFFLING ON INTENSITY OF A POTENTIAL SHOT OF ARCTIC AIR EARLY NEXT WEEK AS PIECE OF POLAR VORTEX ROTATES SOUTH OF HUDSON BAY. BRUNT OF THE ARCTIC BLAST MAY BE DIRECTED FARTHER EAST...BUT STILL LOOKS LIKE THERE COULD BE A PERIOD OF WELL BELOW NORMAL TEMPERATURES EARLY NEXT WEEK. RC && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) ISSUED AT 547 PM CST TUE JAN 27 2015 Main aviation challenges are the current MVFR ceilings and timing the clearing trend tonight. Latest satellite imagery continues to show the cloud cover eroding from the E/NE, with mostly clear skies now being reported along/northeast of a KCMI to KPRG line. HRRR suggests the clouds will continue to slowly dissipate over the next several hours, with clear skies across the board by shortly after midnight. Based on satellite trends and HRRR, have removed the ceiling from KCMI by 01z, then further west to KPIA by around 07z. Winds will initially be quite light from the N/NE this evening, then will veer to E/SE overnight. As the pressure gradient tightens across the region, SE winds will increase markedly on Wednesday. Forecast soundings and numeric guidance suggest gusts in the 20 to 25kt range from late morning through the afternoon hours. Other than high/thin cirrus clouds, skies will be mostly clear through 00z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barnes SHORT TERM...kmd LONG TERM...RC AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
200 PM CST MON JAN 26 2015 .SHORT TERM... 315 AM CST THROUGH TONIGHT... AN IMPRESSIVE WATER VAPOR LOOP THIS MORNING AS ROARING SUBTROPICAL JET ACROSS THE SOUTHEAST IS DEEPENING A SIGNIFICANT SYSTEM THAT WILL IMPACT THE NORTHEAST U.S. OVER THE NEXT 24 TO 36 HOURS. THE NORTHERN STREAM JET WHICH IS ALSO HELPING TO CARVE OUT THE DEVELOPING TROUGH IS DIVING SOUTHWARD OVER OUR REGION TODAY. ON THE CYCLONIC SIDE OF THIS...FROM MANITOBA TO THE LOWER OHIO VALLEY...AN ELONGATED AREA OF VORTICITY GENERATION WILL SUPPORT FORCING FOR ASCENT TODAY AND TONIGHT...WITH THE MOST FOCUSED ZONE BEING A BETTER DEFINED WAVE SEEN OVER CENTRAL MN EARLY THIS MORNING. THE RUN-TO-RUN TREND ON THE RAP MODEL EARLY THIS MORNING IS FURTHER WEST/SOUTHWEST...SUPPORTING UPSTREAM RADAR TRENDS AND FAVORING NORTH CENTRAL IL TO GET IN A PERIOD OF SNOW BEGINNING LATER THIS MORNING FOLLOWED BY A GRADUAL EXPANSION EAST. WHILE MOST OF THE SNOW WILL BE LIGHT...THERE IS A WINDOW OF TIME LATE THIS MORNING AND EARLY THIS AFTERNOON OVER NORTH CENTRAL ILLINOIS WHERE 850-700MB CONVERGENCE AND A F-GEN INDUCED CIRCULATION MAY ALLOW FOR SPOTTY BURSTS OF MODERATE SNOW...WHICH HIGH-RESOLUTION GUIDANCE TRIES TO INDICATE TOO. WITH ADJACENT OFFICES AND WPC COLLABORATION...HAVE AROUND AN INCH FORECAST IN THE ROCKFORD AREA...WITH AROUND A HALF INCH FURTHER EAST OF THERE. SOUTHWARD IN THE FORECAST AREA THE DRY AIR SEEMS MORE PRONOUNCED...SO MAY END UP JUST BEING FLURRIES AT TIMES. THE FORCING ALOFT WEAKENS LATER THIS AFTERNOON AND EVENING SO EXPECTING LIGHT SNOW TO BECOME MORE PATCHY IN COVERAGE. THE MOISTURE IN THE ICE LAYER GRADUALLY DIMINISHES FROM WEST TO EAST THROUGH THE EVENING...WITH STILL SOME LIGHT ADIABATIC ASCENT IN THE LOWEST COUPLE THOUSAND FEET. IF THAT LOWEST LAYER IS SATURATED OR ABLE TO THERE COULD BE A FREEZING DRIZZLE CONCERN...SO MAINTAIN THE GOING CHANCE IN THE FORECAST. FOR TEMPERATURES TODAY...DID BUMP DOWN SEVERAL DEGREES AS CLEARING LAST NIGHT ALLOWED PLACES TO DROP QUICKLY AND NOW THE CLOUD CANOPY WILL HINDER THEM FROM WARMING MUCH. FORECAST HIGHS ARE MAINLY IN THE MID 20S WITH A FEW UPPER 20S POSSIBLE. WHILE THAT DOES NOT MAKE HEADLINES IN JANUARY...IF THE FORECAST PANS OUT THIS WOULD BE THE FIRST DAY WITH HIGHS BELOW 30 SINCE JANUARY 14TH. MTF && .LONG TERM... 315 AM CST TUESDAY THROUGH SUNDAY... HIGH PRESSURE WILL MOVE OVER THE AREA TUESDAY AFTERNOON AND NIGHT BEFORE RETURN FLOW ON WEDNESDAY. THE CHALLENGE OF CLOUD COVER PRESENTS ITSELF AGAIN ON TUESDAY AND WHILE HAVE SLOWED THE CLEARING TREND TUESDAY MORNING...STILL THINK THE AFTERNOON SHOULD SEE SOME BREAKS OF SUN AREAWIDE. SOUTHERLY FLOW ON WEDNESDAY IS FORECAST TO BRING 925MB TEMPERATURES TO AROUND 0C WHICH USING CLIMATOLOGY WITH LIMITED SNOW COVER SHOULD SUPPORT WIDESPREAD MID TO UPPER 30S WITH A FEW LOWER 40S POSSIBLE IN THE SOUTHWEST CWA OR CHICAGO METRO. THE LARGE CLOSED LOW OFF THE BAJA OF CALIFORNIA THIS MORNING IS FORECAST BY THE SUITE OF GUIDANCE TO DRIFT NORTHWARD AND GET CAUGHT UP IN THE WESTERLIES BECOMING AN OPEN WAVE ACROSS THE MIDDLE OF THE COUNTRY. WITH THE MASSIVE SYSTEM OFF THE NORTHEAST LIKELY TO SLOW THINGS A BIT...CONTINUE TO LEAN WITH THE SLOWER EC AND GEM MODELS WHICH WOULD FAVOR PRECIPITATION CHANCES MORE SO LATE WEDNESDAY NIGHT AND THURSDAY...AROUND 12H SLOWER THAN THE GFS. FORECAST VERTICAL PROFILES ON BOTH MODELS WOULD SUPPORT MORE OF RAIN AHEAD OF THIS SYSTEM...ESPECIALLY CONSIDERING LOW-LEVEL TEMPERATURES SHOULD AT THE VERY LEAST HOLD STEADY IF NOT MODERATE WEDNESDAY NIGHT...POTENTIALLY TO 35 TO 38 DEGREES GIVEN EC AND GEM SOLUTIONS. ON THE BACKSIDE OF THIS SYSTEM IT WOULD SEEM THERE WOULD BE AT LEAST A PERIOD OF SNOW CHANCES. OBVIOUSLY A FEW DAYS OUT AND A CUTOFF LOW INVOLVED...A LOT COULD CHANGE WITH SPECIFICS...BUT RIGHT NOW THIS IS NOT LOOKING LIKE A HIGH IMPACT EVENT. LATE THIS WEEK INTO THE WEEKEND THE NORTHERN STREAM FLOW PATTERN IS FORECAST TO REMAIN QUITE PROGRESSIVE WHILE ANOTHER CUTOFF LOW IS PROGGED TO DEVELOP OVER THE FAR SOUTHWEST US. THE 00Z EC HAS FORECAST A STRONG SYSTEM IN THE NORTHWEST FLOW TO WIN OUT ABOUT A WEEK FROM NOW AND DRAG DOWN -15C TO -20C 850MB TEMPERATURES. SOMETHING TO MONITOR AS WE HEAD TOWARD THE FIRST DAYS OF FEBRUARY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * SNOW THIS AFTERNOON WITH MVFR CONDITIONS AND TEMPO IFR...AND LIGHT ACCUMULATIONS LESS THAN AN INCH. * SNOW TAPERING THIS EVENING AND POSSIBLY TRANSITIONING TO OR MIXING WITH DRIZZLE. BMD //DISCUSSION...UPDATED 18Z... SHEARED UPPER LEVEL DISTURBANCE IS HELPING TO DRIVE AN AREA OF SNOW ACROSS ILLINOIS AND WISCONSIN EARLY THIS AFTERNOON. THIS SNOW IS EXPECTED TO MOVE INTO THE CHICAGO AREA OVER THE NEXT COUPLE HOURS. INITIALLY DRY LOW/MID LEVELS WILL TAKE THEIR TIME TO SATURATE AS THE RADAR RETURNS MOVE OVERHEAD...PRECIPITATION INITIALLY EVAPORATING IN THE DRY AIR...BUT THEN EXPECT CONDITIONS TO DETERIORATE TO MVFR WITH TEMPO IFR VSBY IN ANY MODERATE BURSTS OF SNOW. ACCUMULATIONS ARE EXPECTED TO BE FAIRLY MINIMAL...A DUSTING TO AROUND HALF AN INCH OR SO. PRECIPITATION SHOULD BEGIN TO TAPER LATE THIS AFTERNOON OR EARLY THIS EVENING AS UPPER LEVEL RIDGING BEGINS TO BUILD OVERHEAD SUPPRESSING THE DEEPER MOISTURE. ON THE OTHER HAND...PERSISTENT LOW LEVEL CONVERGENCE NEAR THE SURFACE TROUGH MAY RESULT IN WEAK ASCENT LATER INTO THE EVENING WHICH WOULD SUPPORT A FEW FLURRIES...OR POSSIBLY DRIZZLE AT TIMES AS SOUNDINGS INDICATE LOSS OF ICE IN THE COLUMN LATER THIS EVENING AS DRY AIR BUILDS DOWN IN THE UPPER LEVEL SUBSIDENCE. SOUTH WINDS THIS AFTERNOON SHOULD BACK AROUND TO THE NORTHEAST OVERNIGHT. BMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MEDIUM CONFIDENCE IN VSBY/CIG TRENDS WITH PRECIP. * MEDIUM-HIGH CONFIDENCE IN PREVAILING MVFR CIGS DEVELOPING THIS AFTERNOON. * LOW CONFIDENCE IN END TIME OF PRECIP TONIGHT. LOW-MEDIUM CONFIDENCE THAT SNOW MAY CHANGE OR MIX WITH DRIZZLE AT SOME POINT LATE THIS EVENING. BMD //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...MAINLY VFR. WEDNESDAY...MAINLY VFR DURING THE DAY. CHANCE OF RAIN/SNOW AT NIGHT WITH MVFR/IFR POSSIBLE. THURSDAY...CHANCE OF LIGHT SNOW. MVFR LIKELY/IFR POSSIBLE. FRIDAY...MAINLY VFR. SATURDAY...CHANCE OF SNOW/MVFR CIGS. SUNDAY...MVFR CIGS POSSIBLE. RATZER && .MARINE... 143 AM CST ONLY MARINE FORECAST CONCERNS ARE A BRIEF PERIOD OF ENHANCED SOUTH-SOUTHEAST WINDS THIS AFTERNOON AND EVENING ESPECIALLY ON THE NORTHERN PORTION OF THE LAKE...AND AGAIN WEDNESDAY AFTERNOON. GUSTY NORTH WINDS NEAR 30 KT ARE ALSO LIKELY THURSDAY AND THURSDAY NIGHT. WINDS CONTINUE TO DIMINISH QUICKLY ACROSS LAKE MICHIGAN EARLY THIS MORNING...AS WEAK HIGH PRESSURE RIDING SLIDES SOUTHEAST ACROSS THE LAKE. THIS RIDGE WILL ALSO PASS QUICKLY OFF TO THE SOUTHEAST THIS AFTERNOON IN WHAT REMAINS A PROGRESSIVE WEATHER PATTERN...WITH ANOTHER LOW PRESSURE SYSTEM CURRENTLY NEAR LAKE WINNIPEG MOVING QUICKLY SOUTHEAST INTO ILLINOIS BY MIDNIGHT TONIGHT WHILE FILLING. THIS WILL RESULT IN WINDS BECOMING SOUTH AND INCREASING TO AROUND 20 KTS ON THE LAKE THIS AFTERNOON...THEN DECREASING AND BACKING TO THE NORTHEAST INTO TUESDAY MORNING AS THE LOW PASSES AND WEAKENS. ANOTHER HIGH PRESSURE RIDGE WILL SETTLE ACROSS THE WESTERN LAKES BY TUESDAY EVENING. ANOTHER MORE DEVELOPED LOW WILL FORM ACROSS THE LAKES TUESDAY NIGHT...AND WILL DEEPEN SLIGHTLY AS IT APPROACHES FROM THE WEST WEDNESDAY AND PASSES JUST SOUTH OF LAKE MICHIGAN EARLY THURSDAY MORNING. THIS WILL AGAIN RESULT IN WINDS INITIALLY BECOMING SOUTH AND INCREASING TO 20-25 KT WEDNESDAY AFTERNOON AND EVENING...THEN BACKING TO THE NORTH EARLY THURSDAY AND GUSTING NEAR 30 KT AS THE LOW PULLS AWAY ACROSS THE EASTERN LAKES AND UPPER OHIO VALLEY THROUGH THURSDAY AFTERNOON AND NIGHT. HIGH PRESSURE THEN SPREADS ACROSS THE REGION BY FRIDAY AFTERNOON. FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...AS SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL MID-MORNING TODAY...AS WAVES CONTINUE TO SUBSIDE FROM YESTERDAY/LAST EVENINGS STRONG NORTHEAST WINDS. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1255 PM CST Mon Jan 26 2015 .UPDATE... ISSUED AT 1036 AM CST MON JAN 26 2015 Brief wave moving through the region bringing some snowfall for Central Illinois today. Temporary visibility drops associated with the heavier snowfall. Other than some timely adjustments of pops and weather for a more expedient system, forecast actually looking good. Very minor adjustments, but no major updates anticipated at this time. && .SHORT TERM...(Today) ISSUED AT 443 AM CST MON JAN 26 2015 Latest surface analysis indicating weak high pressure centered from central lower Michigan southwest through northeast Missouri. Our next weather system was already producing some light snow across parts of central Minnesota...which was tracking southeast early this morning. The main short term forecast concern will be with this weak upper level system that will track across our area today and the precip chances with it. Models have trended a bit further south and west with the upper wave along with the fairly compact area of lift associated with it. Forcing in the 700-500 mb layer compact but short lived with this system and based on the latest HRRR and RAP solutions, it appears the threat (20-30 POPs) for light snow will track southeast into our area later this morning and then shift into east central Illinois by this afternoon and evening. Forecast soundings have all trended a bit deeper with the moisture with this system and cold enough to support light snow except over far southwest Illinois where there may be a mix of rain and snow for a few hours as surface temps rise into the middle 30s. Despite the decent low to mid level forcing with this wave, QPF amounts will be light with any snow accumulations of less than an inch. As the better forcing shifts off to our east, we start to lose the ice crystals in the upper levels of the clouds that would support mainly light snow. Nam time-height cross sections showing some very weak lift tracking thru the area late this afternoon in the 925-850 mb layer so not the greatest setup for freezing drizzle but will need to be watched later this afternoon and evening. && .LONG TERM...(Tonight through Sunday) ISSUED AT 443 AM CST MON JAN 26 2015 Elongated short wave will gradually shift east of IL by dawn Tue with light snow chances shifting east of IL into Indiana. Low clouds will be slow to clear from the west Tue with mostly cloudy skies generally prevailing with IL river valley having better chance of becoming partly sunny during Tue afternoon. Seasonable highs in the mid to upper 30s Tue with north winds 8-15 mph. Low clouds to continue to decrease Tue night as weak surface high pressure ridge sets up over IL by Tue evening. Lows Tue night in the low to mid 20s. Upper level ridging into IL Wed will give partly to mostly sunny skies, while 1005 mb surface low pressure moving east into the central plains Wed to give breezy sse winds of milder air into the region with highs in the 40s Wed (ranging from lower 40s ne counties to near 50F from Jacksonville sw. Low pressure to move east across central IL during Wed night and bring a chance of light rain with lows staying above freezing in the mid to upper 30s. Light rain chances to diminish from west to east during Thu and could see light snow chances too over northern counties before ending as cooler air arrives on back side of low pressure moving into the southern Great Lakes region. Highs Thu range from upper 30s to near 40F IL river valley to upper 40s in southeast IL. Dry conditions and cooler temps return to central/se IL from Thu night thru Fri night as high pressure settles into the ohio river valley by Friday evening. Highs Fri back to seasonable levels for late Jan in the mid to upper 30s. Continued slight chances of light snow Sat and Sat night as cold front moves through. A cutoff upper level low in the sw states late this week will move east and keeps brunt of its qpf south of central IL, though some models have us on northern edge of lighter qpf this weekend. Also have a northern stream clipper system moving through the Great Lakes Sat and Sat night that drives a cold front through IL. May need to increase chances of light snow this weekend, though timing issues and also question if any phasing can take place better stronger southern stream system and weaken northern stream short wave. Also southern areas could see a mix of precipitation on Sat before colder air arrives Sat night. MEX/GFS appears too warm with temps behind cold front Sun/Mon and oddly doesn`t cool it off much from Sat. ECMWF/ECE model cools off much more Sun/Mon. Did not go as cold as this model, but have temps dropping from highs in upper 30s/near 40F Sat to upper 20s/lower 30s Sunday. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) ISSUED AT 1247 PM CST MON JAN 26 2015 Wave moving through Central Illinois and bringing quick drops in category to IFR and isolated LIFR with some of the heavier snow bands. Heavier showers not always discernible on radar making the TAF trends difficult. PIA and SPI soon to the on the back edge of the heavier snows...with cigs around 2kft...but a few obs with holes to VFR. TAF forecast to the more degraded conditions as moisture saturates through the column and drops categories more widespread through the afternoon and into the overnight hours. Winds becoming more NWrly. Models keeping low cigs through the overnight with some MVFR reductions in vis predominant...with possible patchy drops to IFR. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HJS SHORT TERM...Smith LONG TERM...07 AVIATION...HJS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1155 AM CST MON JAN 26 2015 .SHORT TERM... 315 AM CST THROUGH TONIGHT... AN IMPRESSIVE WATER VAPOR LOOP THIS MORNING AS ROARING SUBTROPICAL JET ACROSS THE SOUTHEAST IS DEEPENING A SIGNIFICANT SYSTEM THAT WILL IMPACT THE NORTHEAST U.S. OVER THE NEXT 24 TO 36 HOURS. THE NORTHERN STREAM JET WHICH IS ALSO HELPING TO CARVE OUT THE DEVELOPING TROUGH IS DIVING SOUTHWARD OVER OUR REGION TODAY. ON THE CYCLONIC SIDE OF THIS...FROM MANITOBA TO THE LOWER OHIO VALLEY...AN ELONGATED AREA OF VORTICITY GENERATION WILL SUPPORT FORCING FOR ASCENT TODAY AND TONIGHT...WITH THE MOST FOCUSED ZONE BEING A BETTER DEFINED WAVE SEEN OVER CENTRAL MN EARLY THIS MORNING. THE RUN-TO-RUN TREND ON THE RAP MODEL EARLY THIS MORNING IS FURTHER WEST/SOUTHWEST...SUPPORTING UPSTREAM RADAR TRENDS AND FAVORING NORTH CENTRAL IL TO GET IN A PERIOD OF SNOW BEGINNING LATER THIS MORNING FOLLOWED BY A GRADUAL EXPANSION EAST. WHILE MOST OF THE SNOW WILL BE LIGHT...THERE IS A WINDOW OF TIME LATE THIS MORNING AND EARLY THIS AFTERNOON OVER NORTH CENTRAL ILLINOIS WHERE 850-700MB CONVERGENCE AND A F-GEN INDUCED CIRCULATION MAY ALLOW FOR SPOTTY BURSTS OF MODERATE SNOW...WHICH HIGH-RESOLUTION GUIDANCE TRIES TO INDICATE TOO. WITH ADJACENT OFFICES AND WPC COLLABORATION...HAVE AROUND AN INCH FORECAST IN THE ROCKFORD AREA...WITH AROUND A HALF INCH FURTHER EAST OF THERE. SOUTHWARD IN THE FORECAST AREA THE DRY AIR SEEMS MORE PRONOUNCED...SO MAY END UP JUST BEING FLURRIES AT TIMES. THE FORCING ALOFT WEAKENS LATER THIS AFTERNOON AND EVENING SO EXPECTING LIGHT SNOW TO BECOME MORE PATCHY IN COVERAGE. THE MOISTURE IN THE ICE LAYER GRADUALLY DIMINISHES FROM WEST TO EAST THROUGH THE EVENING...WITH STILL SOME LIGHT ADIABATIC ASCENT IN THE LOWEST COUPLE THOUSAND FEET. IF THAT LOWEST LAYER IS SATURATED OR ABLE TO THERE COULD BE A FREEZING DRIZZLE CONCERN...SO MAINTAIN THE GOING CHANCE IN THE FORECAST. FOR TEMPERATURES TODAY...DID BUMP DOWN SEVERAL DEGREES AS CLEARING LAST NIGHT ALLOWED PLACES TO DROP QUICKLY AND NOW THE CLOUD CANOPY WILL HINDER THEM FROM WARMING MUCH. FORECAST HIGHS ARE MAINLY IN THE MID 20S WITH A FEW UPPER 20S POSSIBLE. WHILE THAT DOES NOT MAKE HEADLINES IN JANUARY...IF THE FORECAST PANS OUT THIS WOULD BE THE FIRST DAY WITH HIGHS BELOW 30 SINCE JANUARY 14TH. MTF && .LONG TERM... 315 AM CST TUESDAY THROUGH SUNDAY... HIGH PRESSURE WILL MOVE OVER THE AREA TUESDAY AFTERNOON AND NIGHT BEFORE RETURN FLOW ON WEDNESDAY. THE CHALLENGE OF CLOUD COVER PRESENTS ITSELF AGAIN ON TUESDAY AND WHILE HAVE SLOWED THE CLEARING TREND TUESDAY MORNING...STILL THINK THE AFTERNOON SHOULD SEE SOME BREAKS OF SUN AREAWIDE. SOUTHERLY FLOW ON WEDNESDAY IS FORECAST TO BRING 925MB TEMPERATURES TO AROUND 0C WHICH USING CLIMATOLOGY WITH LIMITED SNOW COVER SHOULD SUPPORT WIDESPREAD MID TO UPPER 30S WITH A FEW LOWER 40S POSSIBLE IN THE SOUTHWEST CWA OR CHICAGO METRO. THE LARGE CLOSED LOW OFF THE BAJA OF CALIFORNIA THIS MORNING IS FORECAST BY THE SUITE OF GUIDANCE TO DRIFT NORTHWARD AND GET CAUGHT UP IN THE WESTERLIES BECOMING AN OPEN WAVE ACROSS THE MIDDLE OF THE COUNTRY. WITH THE MASSIVE SYSTEM OFF THE NORTHEAST LIKELY TO SLOW THINGS A BIT...CONTINUE TO LEAN WITH THE SLOWER EC AND GEM MODELS WHICH WOULD FAVOR PRECIPITATION CHANCES MORE SO LATE WEDNESDAY NIGHT AND THURSDAY...AROUND 12H SLOWER THAN THE GFS. FORECAST VERTICAL PROFILES ON BOTH MODELS WOULD SUPPORT MORE OF RAIN AHEAD OF THIS SYSTEM...ESPECIALLY CONSIDERING LOW-LEVEL TEMPERATURES SHOULD AT THE VERY LEAST HOLD STEADY IF NOT MODERATE WEDNESDAY NIGHT...POTENTIALLY TO 35 TO 38 DEGREES GIVEN EC AND GEM SOLUTIONS. ON THE BACKSIDE OF THIS SYSTEM IT WOULD SEEM THERE WOULD BE AT LEAST A PERIOD OF SNOW CHANCES. OBVIOUSLY A FEW DAYS OUT AND A CUTOFF LOW INVOLVED...A LOT COULD CHANGE WITH SPECIFICS...BUT RIGHT NOW THIS IS NOT LOOKING LIKE A HIGH IMPACT EVENT. LATE THIS WEEK INTO THE WEEKEND THE NORTHERN STREAM FLOW PATTERN IS FORECAST TO REMAIN QUITE PROGRESSIVE WHILE ANOTHER CUTOFF LOW IS PROGGED TO DEVELOP OVER THE FAR SOUTHWEST US. THE 00Z EC HAS FORECAST A STRONG SYSTEM IN THE NORTHWEST FLOW TO WIN OUT ABOUT A WEEK FROM NOW AND DRAG DOWN -15C TO -20C 850MB TEMPERATURES. SOMETHING TO MONITOR AS WE HEAD TOWARD THE FIRST DAYS OF FEBRUARY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * SNOW THIS AFTERNOON WITH MVFR CONDITIONS AND TEMPO IFR...AND LIGHT ACCUMULATIONS LESS THAN AN INCH. * SNOW TAPERING THIS EVENING AND POSSIBLY TRANSITIONING TO OR MIXING WITH DRIZZLE. BMD //DISCUSSION...UPDATED 18Z... SHEARED UPPER LEVEL DISTURBANCE IS HELPING TO DRIVE AN AREA OF SNOW ACROSS ILLINOIS AND WISCONSIN EARLY THIS AFTERNOON. THIS SNOW IS EXPECTED TO MOVE INTO THE CHICAGO AREA OVER THE NEXT COUPLE HOURS. INITIALLY DRY LOW/MID LEVELS WILL TAKE THEIR TIME TO SATURATE AS THE RADAR RETURNS MOVE OVERHEAD...PRECIPITATION INITIALLY EVAPORATING IN THE DRY AIR...BUT THEN EXPECT CONDITIONS TO DETERIORATE TO MVFR WITH TEMPO IFR VSBY IN ANY MODERATE BURSTS OF SNOW. ACCUMULATIONS ARE EXPECTED TO BE FAIRLY MINIMAL...A DUSTING TO AROUND HALF AN INCH OR SO. PRECIPITATION SHOULD BEGIN TO TAPER LATE THIS AFTERNOON OR EARLY THIS EVENING AS UPPER LEVEL RIDGING BEGINS TO BUILD OVERHEAD SUPPRESSING THE DEEPER MOISTURE. ON THE OTHER HAND...PERSISTENT LOW LEVEL CONVERGENCE NEAR THE SURFACE TROUGH MAY RESULT IN WEAK ASCENT LATER INTO THE EVENING WHICH WOULD SUPPORT A FEW FLURRIES...OR POSSIBLY DRIZZLE AT TIMES AS SOUNDINGS INDICATE LOSS OF ICE IN THE COLUMN LATER THIS EVENING AS DRY AIR BUILDS DOWN IN THE UPPER LEVEL SUBSIDENCE. SOUTH WINDS THIS AFTERNOON SHOULD BACK AROUND TO THE NORTHEAST OVERNIGHT. BMD //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MEDIUM CONFIDENCE IN SNOW/TIMING BUT LOW-MEDIUM CONFIDENCE IN VSBY/CIG TRENDS WITH PRECIP. * MEDIUM-HIGH CONFIDENCE IN PREVAILING MVFR CIGS DEVELOPING THIS AFTERNOON. * LOW CONFIDENCE IN END TIME OF PRECIP TONIGHT. LOW-MEDIUM CONFIDENCE THAT SNOW MAY CHANGE OR MIX WITH DRIZZLE AT SOME POINT LATE THIS EVENING. BMD //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...MAINLY VFR. WEDNESDAY...MAINLY VFR DURING THE DAY. CHANCE OF RAIN/SNOW AT NIGHT WITH MVFR/IFR POSSIBLE. THURSDAY...CHANCE OF LIGHT SNOW. MVFR LIKELY/IFR POSSIBLE. FRIDAY...MAINLY VFR. SATURDAY...CHANCE OF SNOW/MVFR CIGS. SUNDAY...MVFR CIGS POSSIBLE. RATZER && .MARINE... 143 AM CST ONLY MARINE FORECAST CONCERNS ARE A BRIEF PERIOD OF ENHANCED SOUTH-SOUTHEAST WINDS THIS AFTERNOON AND EVENING ESPECIALLY ON THE NORTHERN PORTION OF THE LAKE...AND AGAIN WEDNESDAY AFTERNOON. GUSTY NORTH WINDS NEAR 30 KT ARE ALSO LIKELY THURSDAY AND THURSDAY NIGHT. WINDS CONTINUE TO DIMINISH QUICKLY ACROSS LAKE MICHIGAN EARLY THIS MORNING...AS WEAK HIGH PRESSURE RIDING SLIDES SOUTHEAST ACROSS THE LAKE. THIS RIDGE WILL ALSO PASS QUICKLY OFF TO THE SOUTHEAST THIS AFTERNOON IN WHAT REMAINS A PROGRESSIVE WEATHER PATTERN...WITH ANOTHER LOW PRESSURE SYSTEM CURRENTLY NEAR LAKE WINNIPEG MOVING QUICKLY SOUTHEAST INTO ILLINOIS BY MIDNIGHT TONIGHT WHILE FILLING. THIS WILL RESULT IN WINDS BECOMING SOUTH AND INCREASING TO AROUND 20 KTS ON THE LAKE THIS AFTERNOON...THEN DECREASING AND BACKING TO THE NORTHEAST INTO TUESDAY MORNING AS THE LOW PASSES AND WEAKENS. ANOTHER HIGH PRESSURE RIDGE WILL SETTLE ACROSS THE WESTERN LAKES BY TUESDAY EVENING. ANOTHER MORE DEVELOPED LOW WILL FORM ACROSS THE LAKES TUESDAY NIGHT...AND WILL DEEPEN SLIGHTLY AS IT APPROACHES FROM THE WEST WEDNESDAY AND PASSES JUST SOUTH OF LAKE MICHIGAN EARLY THURSDAY MORNING. THIS WILL AGAIN RESULT IN WINDS INITIALLY BECOMING SOUTH AND INCREASING TO 20-25 KT WEDNESDAY AFTERNOON AND EVENING...THEN BACKING TO THE NORTH EARLY THURSDAY AND GUSTING NEAR 30 KT AS THE LOW PULLS AWAY ACROSS THE EASTERN LAKES AND UPPER OHIO VALLEY THROUGH THURSDAY AFTERNOON AND NIGHT. HIGH PRESSURE THEN SPREADS ACROSS THE REGION BY FRIDAY AFTERNOON. FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...AS SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL MID-MORNING TODAY...AS WAVES CONTINUE TO SUBSIDE FROM YESTERDAY/LAST EVENINGS STRONG NORTHEAST WINDS. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ 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
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1041 AM CST Mon Jan 26 2015 .UPDATE... ISSUED AT 1036 AM CST MON JAN 26 2015 Brief wave moving through the region bringing some snowfall for Central Illinois today. Temporary visibility drops associated with the heavier snowfall. Other than some timely adjustments of pops and weather for a more expedient system, forecast actually looking good. Very minor adjustments, but no major updates anticipated at this time. && .SHORT TERM...(Today) ISSUED AT 443 AM CST MON JAN 26 2015 Latest surface analysis indicating weak high pressure centered from central lower Michigan southwest through northeast Missouri. Our next weather system was already producing some light snow across parts of central Minnesota...which was tracking southeast early this morning. The main short term forecast concern will be with this weak upper level system that will track across our area today and the precip chances with it. Models have trended a bit further south and west with the upper wave along with the fairly compact area of lift associated with it. Forcing in the 700-500 mb layer compact but short lived with this system and based on the latest HRRR and RAP solutions, it appears the threat (20-30 POPs) for light snow will track southeast into our area later this morning and then shift into east central Illinois by this afternoon and evening. Forecast soundings have all trended a bit deeper with the moisture with this system and cold enough to support light snow except over far southwest Illinois where there may be a mix of rain and snow for a few hours as surface temps rise into the middle 30s. Despite the decent low to mid level forcing with this wave, QPF amounts will be light with any snow accumulations of less than an inch. As the better forcing shifts off to our east, we start to lose the ice crystals in the upper levels of the clouds that would support mainly light snow. Nam time-height cross sections showing some very weak lift tracking thru the area late this afternoon in the 925-850 mb layer so not the greatest setup for freezing drizzle but will need to be watched later this afternoon and evening. && .LONG TERM...(Tonight through Sunday) ISSUED AT 443 AM CST MON JAN 26 2015 Elongated short wave will gradually shift east of IL by dawn Tue with light snow chances shifting east of IL into Indiana. Low clouds will be slow to clear from the west Tue with mostly cloudy skies generally prevailing with IL river valley having better chance of becoming partly sunny during Tue afternoon. Seasonable highs in the mid to upper 30s Tue with north winds 8-15 mph. Low clouds to continue to decrease Tue night as weak surface high pressure ridge sets up over IL by Tue evening. Lows Tue night in the low to mid 20s. Upper level ridging into IL Wed will give partly to mostly sunny skies, while 1005 mb surface low pressure moving east into the central plains Wed to give breezy sse winds of milder air into the region with highs in the 40s Wed (ranging from lower 40s ne counties to near 50F from Jacksonville sw. Low pressure to move east across central IL during Wed night and bring a chance of light rain with lows staying above freezing in the mid to upper 30s. Light rain chances to diminish from west to east during Thu and could see light snow chances too over northern counties before ending as cooler air arrives on back side of low pressure moving into the southern Great Lakes region. Highs Thu range from upper 30s to near 40F IL river valley to upper 40s in southeast IL. Dry conditions and cooler temps return to central/se IL from Thu night thru Fri night as high pressure settles into the ohio river valley by Friday evening. Highs Fri back to seasonable levels for late Jan in the mid to upper 30s. Continued slight chances of light snow Sat and Sat night as cold front moves through. A cutoff upper level low in the sw states late this week will move east and keeps brunt of its qpf south of central IL, though some models have us on northern edge of lighter qpf this weekend. Also have a northern stream clipper system moving through the Great Lakes Sat and Sat night that drives a cold front through IL. May need to increase chances of light snow this weekend, though timing issues and also question if any phasing can take place better stronger southern stream system and weaken northern stream short wave. Also southern areas could see a mix of precipitation on Sat before colder air arrives Sat night. MEX/GFS appears too warm with temps behind cold front Sun/Mon and oddly doesn`t cool it off much from Sat. ECMWF/ECE model cools off much more Sun/Mon. Did not go as cold as this model, but have temps dropping from highs in upper 30s/near 40F Sat to upper 20s/lower 30s Sunday. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 500 AM CST MON JAN 26 2015 Next weather system quickly tracking southeast out of Minnesota this morning and will begin to affect our area after 15z this morning with lower cigs and a period of -SN that may restrict vsbys for a brief time as well. After that, forecast soundings indicate as the system that brings the scattered light snow to the area today moves away, we will lose the ice crystals needed to support light snow with the threat for some freezing drizzle late this afternoon and especially this evening. Not very confident on the freezing drizzle at this point so will not include in the 12z forecast but something to watch for in later forecasts. MVFR cigs still linger at DEC and CMI but based on latest satellite data, they were very close to the backedge of the clouds and will probably scatter the lower cigs out with VFR cigs thereafter until early afternoon when all areas will see cigs lower to MVFR with local IFR cigs in the areas of light snow. For now, will include a tempo group for light snow only at PIA and BMI this afternoon with VCSH for the remainder of the TAF sites. Look for MVFR and occasional IFR cigs to prevail into the evening hours. Surface winds will be out of the south at around 10 kts today with a wind shift into the northwest later this evening with speeds tonight at 5 to 10 kts. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HJS SHORT TERM...Smith LONG TERM...07 AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
549 AM CST MON JAN 26 2015 .SHORT TERM... 315 AM CST THROUGH TONIGHT... AN IMPRESSIVE WATER VAPOR LOOP THIS MORNING AS ROARING SUBTROPICAL JET ACROSS THE SOUTHEAST IS DEEPENING A SIGNIFICANT SYSTEM THAT WILL IMPACT THE NORTHEAST U.S. OVER THE NEXT 24 TO 36 HOURS. THE NORTHERN STREAM JET WHICH IS ALSO HELPING TO CARVE OUT THE DEVELOPING TROUGH IS DIVING SOUTHWARD OVER OUR REGION TODAY. ON THE CYCLONIC SIDE OF THIS...FROM MANITOBA TO THE LOWER OHIO VALLEY...AN ELONGATED AREA OF VORTICITY GENERATION WILL SUPPORT FORCING FOR ASCENT TODAY AND TONIGHT...WITH THE MOST FOCUSED ZONE BEING A BETTER DEFINED WAVE SEEN OVER CENTRAL MN EARLY THIS MORNING. THE RUN-TO-RUN TREND ON THE RAP MODEL EARLY THIS MORNING IS FURTHER WEST/SOUTHWEST...SUPPORTING UPSTREAM RADAR TRENDS AND FAVORING NORTH CENTRAL IL TO GET IN A PERIOD OF SNOW BEGINNING LATER THIS MORNING FOLLOWED BY A GRADUAL EXPANSION EAST. WHILE MOST OF THE SNOW WILL BE LIGHT...THERE IS A WINDOW OF TIME LATE THIS MORNING AND EARLY THIS AFTERNOON OVER NORTH CENTRAL ILLINOIS WHERE 850-700MB CONVERGENCE AND A F-GEN INDUCED CIRCULATION MAY ALLOW FOR SPOTTY BURSTS OF MODERATE SNOW...WHICH HIGH-RESOLUTION GUIDANCE TRIES TO INDICATE TOO. WITH ADJACENT OFFICES AND WPC COLLABORATION...HAVE AROUND AN INCH FORECAST IN THE ROCKFORD AREA...WITH AROUND A HALF INCH FURTHER EAST OF THERE. SOUTHWARD IN THE FORECAST AREA THE DRY AIR SEEMS MORE PRONOUNCED...SO MAY END UP JUST BEING FLURRIES AT TIMES. THE FORCING ALOFT WEAKENS LATER THIS AFTERNOON AND EVENING SO EXPECTING LIGHT SNOW TO BECOME MORE PATCHY IN COVERAGE. THE MOISTURE IN THE ICE LAYER GRADUALLY DIMINISHES FROM WEST TO EAST THROUGH THE EVENING...WITH STILL SOME LIGHT ADIABATIC ASCENT IN THE LOWEST COUPLE THOUSAND FEET. IF THAT LOWEST LAYER IS SATURATED OR ABLE TO THERE COULD BE A FREEZING DRIZZLE CONCERN...SO MAINTAIN THE GOING CHANCE IN THE FORECAST. FOR TEMPERATURES TODAY...DID BUMP DOWN SEVERAL DEGREES AS CLEARING LAST NIGHT ALLOWED PLACES TO DROP QUICKLY AND NOW THE CLOUD CANOPY WILL HINDER THEM FROM WARMING MUCH. FORECAST HIGHS ARE MAINLY IN THE MID 20S WITH A FEW UPPER 20S POSSIBLE. WHILE THAT DOES NOT MAKE HEADLINES IN JANUARY...IF THE FORECAST PANS OUT THIS WOULD BE THE FIRST DAY WITH HIGHS BELOW 30 SINCE JANUARY 14TH. MTF && .LONG TERM... 315 AM CST TUESDAY THROUGH SUNDAY... HIGH PRESSURE WILL MOVE OVER THE AREA TUESDAY AFTERNOON AND NIGHT BEFORE RETURN FLOW ON WEDNESDAY. THE CHALLENGE OF CLOUD COVER PRESENTS ITSELF AGAIN ON TUESDAY AND WHILE HAVE SLOWED THE CLEARING TREND TUESDAY MORNING...STILL THINK THE AFTERNOON SHOULD SEE SOME BREAKS OF SUN AREAWIDE. SOUTHERLY FLOW ON WEDNESDAY IS FORECAST TO BRING 925MB TEMPERATURES TO AROUND 0C WHICH USING CLIMATOLOGY WITH LIMITED SNOW COVER SHOULD SUPPORT WIDESPREAD MID TO UPPER 30S WITH A FEW LOWER 40S POSSIBLE IN THE SOUTHWEST CWA OR CHICAGO METRO. THE LARGE CLOSED LOW OFF THE BAJA OF CALIFORNIA THIS MORNING IS FORECAST BY THE SUITE OF GUIDANCE TO DRIFT NORTHWARD AND GET CAUGHT UP IN THE WESTERLIES BECOMING AN OPEN WAVE ACROSS THE MIDDLE OF THE COUNTRY. WITH THE MASSIVE SYSTEM OFF THE NORTHEAST LIKELY TO SLOW THINGS A BIT...CONTINUE TO LEAN WITH THE SLOWER EC AND GEM MODELS WHICH WOULD FAVOR PRECIPITATION CHANCES MORE SO LATE WEDNESDAY NIGHT AND THURSDAY...AROUND 12H SLOWER THAN THE GFS. FORECAST VERTICAL PROFILES ON BOTH MODELS WOULD SUPPORT MORE OF RAIN AHEAD OF THIS SYSTEM...ESPECIALLY CONSIDERING LOW-LEVEL TEMPERATURES SHOULD AT THE VERY LEAST HOLD STEADY IF NOT MODERATE WEDNESDAY NIGHT...POTENTIALLY TO 35 TO 38 DEGREES GIVEN EC AND GEM SOLUTIONS. ON THE BACKSIDE OF THIS SYSTEM IT WOULD SEEM THERE WOULD BE AT LEAST A PERIOD OF SNOW CHANCES. OBVIOUSLY A FEW DAYS OUT AND A CUTOFF LOW INVOLVED...A LOT COULD CHANGE WITH SPECIFICS...BUT RIGHT NOW THIS IS NOT LOOKING LIKE A HIGH IMPACT EVENT. LATE THIS WEEK INTO THE WEEKEND THE NORTHERN STREAM FLOW PATTERN IS FORECAST TO REMAIN QUITE PROGRESSIVE WHILE ANOTHER CUTOFF LOW IS PROGGED TO DEVELOP OVER THE FAR SOUTHWEST US. THE 00Z EC HAS FORECAST A STRONG SYSTEM IN THE NORTHWEST FLOW TO WIN OUT ABOUT A WEEK FROM NOW AND DRAG DOWN -15C TO -20C 850MB TEMPERATURES. SOMETHING TO MONITOR AS WE HEAD TOWARD THE FIRST DAYS OF FEBRUARY. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * LIGHT SNOW DEVELOPING AROUND MID-DAY. MVFR CIGS/IFR VSBY POSSIBLE THIS AFTERNOON. MINOR ACCUMULATIONS. * IFR CIGS AND MVFR FOG POSSIBLE TONIGHT WITH LINGERING FLURRIES. * LIGHT/VARIABLE WINDS BECOME LIGHT SOUTH TODAY AND SOUTHEAST THIS EVENING. GENERALLY LESS THAN 10 KT. WINDS THEN BECOME LIGHT EAST-NORTHEAST LATE TONIGHT. RATZER //DISCUSSION...UPDATED 12Z... WEAK SURFACE HIGH PRESSURE OVER THE AREA WILL MOVE QUICKLY OFF TO THE SOUTHEAST THIS MORNING...AS AN AREA OF LOW PRESSURE RAPIDLY APPROACHES FROM THE UPPER MIDWEST. VFR CLOUDS EXPECTED TO LOWER THROUGH THE MORNING...WITH DEVELOPMENT OF LIGHT SNOW AND MVFR CIGS BY/AROUND MID-DAY. A PERIOD OF LIGHT ACCUMULATING SNOW IS LIKELY THROUGH THE AFTERNOON...WITH OCCASIONAL IFR VSBYS. SNOW IS EXPECTED TO TAPER OFF BY EVENING THOUGH WILL LINGER IN LIGHTER FASHION AND MAY MIX OR CHANGE TO FREEZING DRIZZLE LATE BEFORE ENDING. MOIST LOW LEVELS AND LIGHT WINDS SUPPORT A PERIOD OF IFR CIGS AND MVFR VSBYS IN FOG OVERNIGHT AS THE SURFACE LOW FILLS TO JUST A TROUGH. SNOW ACCUMULATIONS LOOK TO RANGE FROM PERHAPS AN INCH AROUND RFD...TO LESS THAN AN INCH FARTHER EAST ACROSS CHI METRO TERMINALS. WINDS CURRENTLY LIGHT/VARIABLE AS THE SURFACE RIDGE AXIS PASSES ACROSS THE FORECAST AREA EARLY THIS MORNING. WINDS TO SHIFT SOUTH DURING THE MORNING...THEN SOUTHEAST BY EVENING. SPEEDS GENERALLY LESS THAN 10 KTS...THOUGH IF APPROACHING LOW IS SLOWER TO WEAKEN THAN EXPECTED SOUTHEAST WINDS AROUND 10 KT WOULD BE POSSIBLE LATER THIS AFTERNOON. WINDS TO TURN LIGHT NORTHEAST LATER TONIGHT INTO EARLY TUESDAY. RATZER //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN WIND TRENDS. * MEDIUM CONFIDENCE IN SNOW TIMING/INTENSITY TODAY INTO THIS EVENING. * MEDIUM-LOW CONFIDENCE IN VIS/CIG TRENDS OVERNIGHT. RATZER //OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z... TUESDAY NIGHT...MAINLY VFR. WEDNESDAY...MAINLY VFR DURING THE DAY. CHANCE OF RAIN/SNOW AT NIGHT WITH MVFR/IFR POSSIBLE. THURSDAY...CHANCE OF LIGHT SNOW. MVFR LIKELY/IFR POSSIBLE. FRIDAY...MAINLY VFR. SATURDAY...CHANCE OF SNOW/MVFR CIGS. SUNDAY...MVFR CIGS POSSIBLE. RATZER && .MARINE... 143 AM CST ONLY MARINE FORECAST CONCERNS ARE A BRIEF PERIOD OF ENHANCED SOUTH-SOUTHEAST WINDS THIS AFTERNOON AND EVENING ESPECIALLY ON THE NORTHERN PORTION OF THE LAKE...AND AGAIN WEDNESDAY AFTERNOON. GUSTY NORTH WINDS NEAR 30 KT ARE ALSO LIKELY THURSDAY AND THURSDAY NIGHT. WINDS CONTINUE TO DIMINISH QUICKLY ACROSS LAKE MICHIGAN EARLY THIS MORNING...AS WEAK HIGH PRESSURE RIDING SLIDES SOUTHEAST ACROSS THE LAKE. THIS RIDGE WILL ALSO PASS QUICKLY OFF TO THE SOUTHEAST THIS AFTERNOON IN WHAT REMAINS A PROGRESSIVE WEATHER PATTERN...WITH ANOTHER LOW PRESSURE SYSTEM CURRENTLY NEAR LAKE WINNIPEG MOVING QUICKLY SOUTHEAST INTO ILLINOIS BY MIDNIGHT TONIGHT WHILE FILLING. THIS WILL RESULT IN WINDS BECOMING SOUTH AND INCREASING TO AROUND 20 KTS ON THE LAKE THIS AFTERNOON...THEN DECREASING AND BACKING TO THE NORTHEAST INTO TUESDAY MORNING AS THE LOW PASSES AND WEAKENS. ANOTHER HIGH PRESSURE RIDGE WILL SETTLE ACROSS THE WESTERN LAKES BY TUESDAY EVENING. ANOTHER MORE DEVELOPED LOW WILL FORM ACROSS THE LAKES TUESDAY NIGHT...AND WILL DEEPEN SLIGHTLY AS IT APPROACHES FROM THE WEST WEDNESDAY AND PASSES JUST SOUTH OF LAKE MICHIGAN EARLY THURSDAY MORNING. THIS WILL AGAIN RESULT IN WINDS INITIALLY BECOMING SOUTH AND INCREASING TO 20-25 KT WEDNESDAY AFTERNOON AND EVENING...THEN BACKING TO THE NORTH EARLY THURSDAY AND GUSTING NEAR 30 KT AS THE LOW PULLS AWAY ACROSS THE EASTERN LAKES AND UPPER OHIO VALLEY THROUGH THURSDAY AFTERNOON AND NIGHT. HIGH PRESSURE THEN SPREADS ACROSS THE REGION BY FRIDAY AFTERNOON. FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...AS SMALL CRAFT ADVISORY REMAINS IN EFFECT UNTIL MID-MORNING TODAY...AS WAVES CONTINUE TO SUBSIDE FROM YESTERDAY/LAST EVENINGS STRONG NORTHEAST WINDS. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 AM MONDAY. && $$ 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
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 507 AM CST Mon Jan 26 2015 .SHORT TERM...(Today) ISSUED AT 443 AM CST MON JAN 26 2015 Latest surface analysis indicating weak high pressure centered from central lower Michigan southwest through northeast Missouri. Our next weather system was already producing some light snow across parts of central Minnesota...which was tracking southeast early this morning. The main short term forecast concern will be with this weak upper level system that will track across our area today and the precip chances with it. Models have trended a bit further south and west with the upper wave along with the fairly compact area of lift associated with it. Forcing in the 700-500 mb layer compact but short lived with this system and based on the latest HRRR and RAP solutions, it appears the threat (20-30 POPs) for light snow will track southeast into our area later this morning and then shift into east central Illinois by this afternoon and evening. Forecast soundings have all trended a bit deeper with the moisture with this system and cold enough to support light snow except over far southwest Illinois where there may be a mix of rain and snow for a few hours as surface temps rise into the middle 30s. Despite the decent low to mid level forcing with this wave, QPF amounts will be light with any snow accumulations of less than an inch. As the better forcing shifts off to our east, we start to lose the ice crystals in the upper levels of the clouds that would support mainly light snow. Nam time-height cross sections showing some very weak lift tracking thru the area late this afternoon in the 925-850 mb layer so not the greatest setup for freezing drizzle but will need to be watched later this afternoon and evening. && .LONG TERM...(Tonight through Sunday) ISSUED AT 443 AM CST MON JAN 26 2015 Elongated short wave will gradually shift east of IL by dawn Tue with light snow chances shifting east of IL into Indiana. Low clouds will be slow to clear from the west Tue with mostly cloudy skies generally prevailing with IL river valley having better chance of becoming partly sunny during Tue afternoon. Seasonable highs in the mid to upper 30s Tue with north winds 8-15 mph. Low clouds to continue to decrease Tue night as weak surface high pressure ridge sets up over IL by Tue evening. Lows Tue night in the low to mid 20s. Upper level ridging into IL Wed will give partly to mostly sunny skies, while 1005 mb surface low pressure moving east into the central plains Wed to give breezy sse winds of milder air into the region with highs in the 40s Wed (ranging from lower 40s ne counties to near 50F from Jacksonville sw. Low pressure to move east across central IL during Wed night and bring a chance of light rain with lows staying above freezing in the mid to upper 30s. Light rain chances to diminish from west to east during Thu and could see light snow chances too over northern counties before ending as cooler air arrives on back side of low pressure moving into the southern Great Lakes region. Highs Thu range from upper 30s to near 40F IL river valley to upper 40s in southeast IL. Dry conditions and cooler temps return to central/se IL from Thu night thru Fri night as high pressure settles into the ohio river valley by Friday evening. Highs Fri back to seasonable levels for late Jan in the mid to upper 30s. Continued slight chances of light snow Sat and Sat night as cold front moves through. A cutoff upper level low in the sw states late this week will move east and keeps brunt of its qpf south of central IL, though some models have us on northern edge of ligher qpf this weekend. Also have a northern stream clipper system moving through the Great Lakes Sat and Sat night that drives a cold front through IL. May need to increase chances of light snow this weekend, though timing issues and also question if any phasing can take place bettern stronger southern stream system and weakern northern stream short wave. Also southern areas could see a mix of precipitation on Sat before colder air arrives Sat night. MEX/GFS appears too warm with temps behind cold front Sun/Mon and oddly doesn`t cool it off much from Sat. ECWMF/ECE model cools off much more Sun/Mon. Did not go as cold as this model, but have temps dropping from highs in upper 30s/near 40F Sat to upper 20s/lower 30s Sunday. && .AVIATION...(For the 12Z TAFS through 12Z Tuesday morning) ISSUED AT 500 AM CST MON JAN 26 2015 Next weather system quickly tracking southeast out of Minnesota this morning and will begin to affect our area after 15z this morning with lower cigs and a period of -SN that may restrict vsbys for a brief time as well. After that, forecast soundings indicate as the system that brings the scattered light snow to the area today moves away, we will lose the ice crystals needed to support light snow with the threat for some freezing drizzle late this afternoon and especially this evening. Not very confident on the freezing drizzle at this point so will not include in the 12z forecast but something to watch for in later forecasts. MVFR cigs still linger at DEC and CMI but based on latest satellite data, they were very close to the backedge of the clouds and will probably scatter the lower cigs out with VFR cigs thereafter until early afternoon when all areas will see cigs lower to MVFR with local IFR cigs in the areas of light snow. For now, will include a tempo group for light snow only at PIA and BMI this afternoon with VCSH for the remainder of the TAF sites. Look for MVFR and occasional IFR cigs to prevail into the evening hours. Surface winds will be out of the south at around 10 kts today with a wind shift into the northwest later this evening with speeds tonight at 5 to 10 kts. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Smith LONG TERM...07 AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1154 PM CST SUN JAN 25 2015 .UPDATE... 820 PM CST PCPN IS WINDING DOWN ACROSS THE AREA WITH ONLY SOME LINGERING LIGHT SNOW SOUTH OF THE KANKAKEE RIVER. WHILE WINDS ARE CURRENTLY STILL RATHER BREEZY ACROSS THE AREA...THE GENERAL TREND OF THE REMAINDER OF THE EVENING AND OVERNIGHT SHOULD BE FOR WINDS TO DIMINISH AND ANY LINGERING SNOW SHOULD PUSH OUT OF THE AREA. TEMPERATURES SHOULD ALSO DROP OFF WITH PARTIALLY CLEARING SKIES AND SOME COOLER AIR FILTERING IN AS THE LOW PRESSURE CENTER ASSOCIATED WITH THE SYSTEM THAT BROUGHT TODAY`S PRECIPITATION MOVES OFF TO THE SOUTHEAST. HAVE MADE SOME CHANGES TO THE GOING FORECAST FOR TOMORROW. THE LATEST 00Z MODEL RUNS ARE TRENDING TOWARD THE NEXT CLIPPER DROPPING A LITTLE FARTHER SOUTH...WITH SOME MODEST LIFT IN THE ZONE AHEAD OF A WEAK WARM FRONT ASSOCIATED WITH THE NEXT CLIPPER. SO HAVE INCREASED POPS...WITH LIKELY POPS FOR THE AFTERNOON HOURS ACROSS MUCH OF THE AREA...WITH THE EXCEPTION OF THE FAR SOUTHERN PORTIONS OF THE CWA. ALSO...THE THERMAL PROFILES IN THE LATEST MODEL SOUNDINGS SUGGEST THAT THE PCPN SHOULD BE ALL SNOW...WITH A DEEP ENOUGH SATURATED LAYER TO SUPPORT ALL SNOW...AND LESSER CHANCES FOR FREEZING DRIZZLE. SO...HAVE REMOVED THE FREEZING DRIZZLE MENTION FOR THE DAYTIME HOURS. STILL FEEL THAT THERE IS A BETTER CHANCE FOR FREEZING DRIZZLE TOMORROW NIGHT AS DRIER AIR ALOFT LOWERS THE DEPTH OF THE SATURATED LAYER ENOUGH TO MINIMIZE THE CHANCE FOR ICE PRODUCTION IN THE SATURATED LAYER. WHILE POPS HAVE BEEN RAISED...THERE IS LITTLE AVAILABLE DEEP LAYER MOISTURE...SO ACTUAL SNOWFALL AMOUNTS SHOULD BE LIGHT...ONLY PERHAPS A COUPLE TENTHS OF AN INCH OF ACCUMULATION. KREIN && .SHORT TERM... 206 PM CST TONIGHT THROUGH MONDAY NIGHT... COOL AIR HAS STRUGGLED TO SLIDE SOUTH THIS AFTERNOON...HOWEVER TEMPS ARE BEGINNING TO FALL INTO THE UPR 20S ACROSS FAR NORTHEAST IL. ACROSS THE CENTRAL/SOUTHERN CWFA TEMPS REMAIN IN THE LOW 30S WITH DEW POINT DEPRESSIONS NOT MUCH MORE THAN 1 TO 2 DEGREES. NORTH OF I-80 PRECIP IS MAINLY FLURRIES...WITH A RAIN/SNOW MIX SLOWLY CHANGING TO ALL SNOW LATER THIS AFTERNOON ACROSS THE SOUTHERN CWFA. THE SHORTWAVE THAT BROUGHT THE LIGHT SNOW CONTINUES TO SLIDE EAST ACROSS SOUTHERN IL...AND WILL STEADILY BRING AN END TO THE PRECIP ACROSS THE FORECAST AREA THIS EVENING FROM NORTHWEST TO SOUTHEAST. WINDS WILL GRADUALLY DIMINISH AS WELL AS THE PRESSURE GRADIENT RELAXES. SFC RIDGE CENTERED TO THE NORTH THIS AFTERNOON...WILL SAG SOUTH AND EXPAND TO COVER A PORTION OF THE WESTERN GREAT LAKES/MISSOURI VALLEY OVERNIGHT. WHILE SOME EROSION TO THE CLOUDS IS PROBABLE NORTH OF THE FORECAST AREA...EXPECT SOME DECREASE IN CLOUDS CLOSER TO DAYBREAK MON. CURRENTLY EXPECT OVERNIGHT LOWS TO DIP INTO THE MID/UPR TEENS...HOWEVER THIS WILL LIKELY NOT OCCUR UNTIL CLOSER TO DAYBREAK MON. THE BRIEF BREAK IN CLOUDS MON MORNING WILL QUICKLY GIVE WAY TO THE NEXT CLIPPER SYSTEM ARRIVING MON AFTN/EVE. GUIDANCE HAS MAINTAINED A PROGRESSIVE LOOK TO THIS NEXT WAVE...HOWEVER OPERATIONAL SOLUTIONS ARE EQUALLY BULLISH ON EROSION OF MOISTURE WITHIN THE LOWEST FEW LAYERS OF THE ATMOS LATE MON NGT. HAVE SOME CONCERN ABOUT P-TYPE MON AFTN/EVE. AT THE ONSET MOISTURE WILL QUICKLY SATURATE THRU THE -10 DEG C LAYER AND TOUCH THE FAVORED DGZ...HOWEVER THE DEPTH OF THE MOISTURE BECOMES MORE SHALLOW MON EVE. ALONG WITH THE LACK OF GOOD LIFT AND SHALLOW MOISTURE...IT IS LOOKING MORE LIKELY THAT PRECIP MAY BE A MIX OF FREEZING DRIZZLE/LGT-SNOW. A WEAK THERMAL RIDGE TRIES TO PUSH OVERHEAD MON AFTN...AS LLVL FLOW TURNS SOUTHWESTERLY. TEMPS SHUD HOVER ARND FREEZING...HOWEVER THIS WILL HINGE ON CLOUD COVER ARRIVAL AND DEVELOPMENT OF PRECIP. IF THIS IS DELAYED...TEMPS COULD PUSH A FEW DEGREES WARMER MON EARLY AFTN. HEIGHTS SLOWLY INCREASE MON NGT...WITH THE MOISTURE PEELING EAST ALONG WITH THE WEAKENING SHORTWAVE. AT THIS TIME HAVE MAINTAINED A MENTION OF LGT SNOW OR PATCHY FREEZING DRIZZLE MON NGT...BUT COULD END UP WITH A DRY PERIOD. BEACHLER && .LONG TERM... 206 PM CST TUESDAY THROUGH SUNDAY... TOWARDS THE MIDDLE OF THE WEEK ENSEMBLES MAINTAIN A HIGH CONFIDENCE IN THE TROUGH ALONG THE SOUTHEAST CONUS WEAKENING WITH RIDGING EXPANDING EAST ACROSS THE CENTRAL PLAINS. THIS SHUD PLACE THE BULK OF THE REGION INTO A WEAK SFC RIDGE TUE/WED. WED AFTN THE SFC RIDGE QUICKLY SLIDES SOUTHEAST...WHICH COULD ALLOW SOME WARM AIR TO ADVECT NORTHEAST INTO THE CWFA AND PUSH SFC TEMPS CLOSE TO 40 DEG. WITH A QUASI-ZONAL SETUP WED NGT/THUR...GUIDANCE SUGGESTS A ROBUST MID-LVL VORT WILL QUICKLY SLIDE EAST FROM THE ROCKIES TOWARDS THE PLAINS WED EVE. GUIDANCE THEN FURTHER STRENGTHENS THIS WAVE AND LIFTS NORTHEAST ACROSS THE FORECAST AREA THUR. SOUNDINGS SUGGESTS THAT PRECIP COULD START AS MAINLY RAIN WITH THIS SYSTEM...THEN DYNAMICALLY COOL OVERNIGHT INTO THUR AND TRANSITION PRECIP OVER TO LGT SNOW. A RELATIVELY ACTIVE PATTERN CONTINUES TOWARDS THE END OF THE WEEK INTO EARLY NEXT WEEKEND...WITH TEMPS GENERALLY IN THE UPR 20S/LOW 30S. BEACHLER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * BRIEF HIGH-END MVFR CIGS OFF LAKE MICHIGAN SHOULD SCATTER BY SUNRISE. * PERIOD OF LIGHT SNOW POSSIBLE THIS AFTERNOON/EVENING WITH REDEVELOPMENT OF MVFR CIGS WHICH LINGER TONIGHT. RATZER //DISCUSSION...UPDATED 06Z... WEAK HIGH PRESSURE RIDGE QUICKLY MOVING INTO FORECAST AREA FROM THE NORTHWEST OVERNIGHT...THOUGH NORTHEAST WINDS HAVE RESULTED IN A LAKE-INDUCED PLUME OF MVFR STRATOCU FROM ABOUT ORD EAST...WITH BASES AROUND 2500 FT. THESE CIGS WILL LIKELY AFFECT ORD/MDW/GYY UNTIL ABOUT SUNRISE...WHEN MODELS DEPICT NORTHEAST FLOW QUICKLY BECOMING DISORGANIZED WITH APPROACH OF SFC RIDGE. SFC WINDS TO BECOME LIGHT/VARIABLE FOR A TIME THIS MORNING AS THE SURFACE HIGH PRESSURE RIDGE MOVES ACROSS THE TERMINALS...GENERALLY FLOPPING FROM LIGHT NORTHERLY TO LIGHT SOUTHERLY BY MID-DAY. IR SATELLITE PICS ALREADY SHOWING HIGH CLOUDS SPILLING INTO THE REGION FROM THE NORTHWEST AHEAD OF THE NEXT WEAK CLIPPER SYSTEM WHICH WILL AFFECT THE AREA MONDAY AFTERNOON/EVENING. LOW LEVELS ARE INITIALLY DRY AND WILL TAKE SOME WORK TO SATURATE FROM ABOVE AS MID-LEVEL FORCING INCREASES MID-DAY INTO EARLY AFTERNOON. MOST GUIDANCE DOES INDICATE SOME LIGHT SNOW DEVELOPING DURING THE PERIOD...THOUGH A COMBINATION OF WEAKENING FORCING AND FORCING FOCUSED BELOW TEMP LAYER CONDUCIVE TO LARGER SNOWFLAKE GROWTH SUGGESTS THIS WILL BE RATHER LIGHT. WHILE A FEW INCONSEQUENTIAL FLURRIES COULD BEGIN SOONER...THE TIMING OF THE PERIOD MOST LIKELY TO SEE SOME LIGHT SNOW AND MVFR CIG/POSSIBLE IFR VSBY LOOKS TO BE DURING THE AFTERNOON AT RFD...AND DURING THE LATE AFTN/EARLY EVENING FOR CHICAGO TERMINALS. SNOW SHOULD TAPER OFF DURING THE EVENING AT RFD AND BY LATE EVENING FOR CHICAGO TERMINALS...WITH LOSS OF STRONGER LIFT AND DRYING IN MID-LEVELS. SOME INDICATION THAT THERE COULD BE A BRIEF PERIOD OF FREEZING DRIZZLE AS THE SNOW ENDS ESPECIALLY AT RFD WHERE MID-LEVELS DRY A LITTLE MORE QUICKLY...THOUGH MODELS MAY BE OVERDOING THE DEGREE OF SATURATION IN THE BOUNDARY LAYER AND CONFIDENCE IS LOW THAT FZDZ WOULD OCCUR. IT DOES HOWEVER APPEAR THAT SOME SORT OF HIGH-IFR OR LOW-MVFR CIG MAY LINGER DURING THE NIGHT. RATZER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH IN WIND TRENDS. * MEDIUM-LOW IN SNOW TIMING/INTENSITY THIS AFTERNOON AND EVENING. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY...MVFR CIGS POSSIBLE. WEDNESDAY...VFR DURING THE DAY THEN CHANCE OF -RASN AND MVFR/IFR AT NIGHT. THURSDAY...CHANCE OF RAIN/SNOW. MVFR LIKELY/IFR POSSIBLE. FRIDAY...CHANCE OF MVFR CIGS...ESPECIALLY EARLY. SATURDAY...CHANCE OF LIGHT SNOW/MVFR CIGS. IZZI && .MARINE... 131 PM CST A QUICK MOVING CLIPPER SYSTEM...CURRENTLY CENTERED ACROSS SOUTHERN ILLINOIS...WILL RAPIDLY SHIFT EASTWARD TOWARDS THE ATLANTIC COAST BY MONDAY MORNING. NORTHEASTERLY WINDS OF 30-35 KT CONTINUE ACROSS THE SOUTHERN 1/3RD OF LAKE MICHIGAN...AND THESE WINDS LOOK TO CONTINUE FOR THE NEXT FEW HOURS...BEFORE A DIMINISHING TREND BEGINS EARLY THIS EVENING. ANOTHER WEAKENING LOW WILL SHIFT SOUTHWARD JUST WEST OF THE LAKE LATE MONDAY AND MONDAY NIGHT. THIS WILL RESULT IN A PERIOD OF SOUTHERLY WINDS OVER THE LAKE DURING THIS PERIOD. LATER IN THE WEEK ANOTHER LOW IS EXPECTED TO IMPACT THE GREAT LAKES REGION. THIS SYSTEM STILL HAS THE POTENTIAL TO PRODUCE A PERIOD OF STRONG SOUTHERLY WINDS LATE WEDNESDAY AND WEDNESDAY NIGHT...FOLLOWED BY A PERIOD OF STRONG NORTHERLY WINDS THURSDAY INTO EARLY FRIDAY. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 9 AM MONDAY. && $$ 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
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1121 PM CST Sun Jan 25 2015 .UPDATE... ISSUED AT 835 PM CST SUN JAN 25 2015 Have tweaked temps/winds/sky for tonight and flurries for tomorrow. For most part current package is on track. Precip coming to an end as surface system over central KY continues to pull away from Illinois. Still could be a snow or rain shower over the next several hours east of I-57, but for the most part any significant precip has ended. Weak ridge is building into Illinois from the northeast scattering out the cloudcover over western Illinois this evening. This partial clearing will likely spread only slowly south and east and then be overtaken by clouds associated with next quick system for Monday. Moisture remains quite limited with this second cliper and for now will keep only flurry wording. Forecast soundings from 18z NAM and GFS suggest that there also could be some freezing drizzle/sprinkles as the atmospheric column is expected to be quite dry above -8C and it may be difficult to form ice crystals. Will have to look closer at this potential once the full 00z model suite has been analyzed. && .SHORT TERM...(Tonight) ISSUED AT 239 PM CST SUN JAN 25 2015 Area of low pressure which has brought our precipitation was centered near Carbondale early this afternoon. Rain/snow transition line has been struggling to move any further south, and in fact areas from Macomb to Bloomington which had switched over were starting to mix with rain again. Temperatures have been above freezing over most of the snow area and accumulations have been minor and slushy, but some more substantial 1-2 inch totals have occurred north of Galesburg where temperatures are now below freezing. The deformation band of snow has been weakening some the last few hours, and there is a substantial hole in the precip over the central 2/3 of the forecast area. The RAP model shows a further weakening of the the deformation band over the next few hours, and actually has the entire CWA dry by 6 pm. Have some concerns that may be too quick across the southeast, as the upper wave continues to dig across southeast Missouri, and have lingered some likely PoP`s down there slightly beyond that time frame, but reduced PoP`s to below 20% by 9 pm. Overnight, models are trying to show some substantial clearing over most of the forecast area beginning late evening. While there is some breakup of the clouds upstream across Wisconsin, it is not completely clear up there and the north/northeast flow is not especially conducive to rapid clearing. Have gone with partly cloudy skies overnight across the northwest half of the forecast area, but clouds will already been increasing ahead of the next clipper which will be dropping southeast into northern Minnesota overnight. && .LONG TERM...(Monday through Sunday) ISSUED AT 239 PM CST SUN JAN 25 2015 A couple of cooler days are on tap across central and southeast Illinois in the wake of today`s clipper. There is still a chance we may see a few snow flakes or sprinkles on Monday as a shearing upper-level wave, currently diving across the Canadian Prairies, passes through the Great Lakes region and parts of the Midwest. However, looking at forecast soundings, there will be a very small window of opportunity where ice crystals will be present, suggesting the chance of measurable precipitation is quite low. So, for now, will only carry a chance of flurries Monday across the northern portion of the forecast area as the very sheared wave passes to our north. It is definitely possible that we will see nothing at all, or perhaps some light drizzle or freezing drizzle (depending on surface temperatures) due to the paucity of ice crystals. Temperatures will warm heading into midweek as the persistent amplified upper-level flow briefly turns more zonal, and a system approaches from the Pacific coast. This system will mainly pose a rain threat as it moves through Wednesday night into Thursday. A brief period of snow is not out of the question later Thursday as cold air filters in behind the system, but forecast soundings currently suggest the moisture depth will be too shallow to support precipitation (no ice crystals) by the time the thermal profile would support snow. Another cool down is expected in the wake of the midweek system, but temperatures should still be near normal for late January. The eastern North American mean trof that has been in place will try to reestablish itself by the weekend. A clipper type wave in the returning northwest upper-level flow may bring a chance of snow to the area over the weekend. However, the current storm track keeps the best snow chances to our north, and have only included a slight chance of snow at this time. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) ISSUED AT 1120 PM CST SUN JAN 25 2015 Clearing area associated with weak ridge building into Illinois has slowed its southeast progress near I-55. High clouds from next cliper system already beginning to cross Mississippi River and will likely overspread sites experiencing clearing over next few hours. NAM from 00z suggests that partial clearing will resume its progress slowly southeast after 06z, but that will be followed by MVFR deck from next system during the day Monday. Model suite from 00z a bit further south with low measurable pops and impacts all TAF sites at one time or another. Forecast soundings suggest that there may still be some potential for FZDZ given the dry air in crystal formation layer. Will include about a 4-hr tempo group for I-74 terminals for -SN at this time but later shifts will need to monitor closely. Winds are diminishing quickly as the gradient weakens as the surface ridge moves in. Winds should shift around to the south Monday and then back to the northwest after the cold front passage associated with the cliper which will likely be just beyond the valid time of this set of terminals. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barker SHORT TERM...Geelhart LONG TERM...Bak AVIATION...Barker
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1147 AM CST MON JAN 26 2015 .UPDATE... ISSUED AT 558 AM CST MON JAN 26 2015 INTRODUCED PATCHY FZDZ/FLURRIES BETWEEN HIGHWAY 20 TO HIGHWAY 34 AND GENERALLY EAST OF HIGHWAY 169 THROUGH 14Z WITH THE WEAK BAND OF PRECIP QUICKLY MOVING SOUTH THAT IS JUST MOVING INTO THE FORT DODGE AREA AS OF 6 AM. ALGONA AND FOREST CITY REPORTING UP...ONLY CONFIRMING PRECIP IS FINALLY ABLE TO REACH THE SURFACE. SHOULD BE VERY SHORT-LIVED AND LOOKS TO EXIT THE DSM METRO BY 730-8AM. .SHORT TERM /TODAY/... ISSUED AT 318 AM CST MON JAN 26 2015 QUICK MOVING SHORTWAVE LOOKS TO BRING SOME VERY LIGHT SNOW/FZDZ TO NORTHERN AND EASTERN PORTIONS OF THE FORECAST THIS MORNING. TIMING OF ANY PRECIP LOOKS TO BE FROM 10Z TO 14Z WITH SOME LINGERING POPS THROUGH 15Z NEAR THE ALO AREA. LEANED TOWARD A BLEND OF THE NAM12/RAP FOR POPS TODAY AND TOWARDS THE WARMER RAP/ECMWF FOR TEMPS. THE RAP AND NAM MCW/FOD SOUNDINGS HAVE A TOUGH TIME GETTING COMPLETELY SATURATED AS THEY DEPICT A DEEP DRY LAYER BETWEEN 850- 650MB. CERTAINLY SATURATED BELOW 850MB AND ABOVE 650MB...SO SEEDER FEEDER POTENTIAL EXISTS BUT FORCING WITHIN THE DENDRITIC LAYER IS VERY WEAK AND ANY SNOW WILL HAVE A DIFFICULT TIME MAKING IT THROUGH THIS DRY LAYER. IT MAY SNOW FOR A SHORT STINT BY AROUND 12Z-13Z ONCE THE COLUMN COMPLETELY SATURATES NEAR MCW/ALO AREA BUT THE RAP KEEPS THE DRY LAYER THROUGH THE ENTIRE MORNING. AS A RESULT...WITH THE LACK OF ANY ICE INTRODUCTION...HAVE MENTION OF FZDZ THIS MORNING. ONLY A MINOR TRAVEL CONCERN WITH THE FZDZ AS EXPECTING WARMER TEMPERATURES LOOK TO ADVECT IN AND WITH THE VERY QUICK MOVING SHORTWAVE...THE PRECIP SHOULD BE SHORT-LIVED AND SPORADIC AT BEST. PLUS...MUCH OF THE PRECIP RETURNS ON RADAR IN SOUTHERN MINNESOTA ARE NOT REACHING THE GROUND WITH ONLY A COUPLE SPOTS REPORTING -SN ATTM. WAA WILL CONTINUE THROUGH MUCH OF THE MORNING INTO THE EARLY AFTERNOON AND UTILIZED A BLEND OF THE RAP/ECMWF FOR MAX TEMPS TODAY. THE NAM/GFS/SREF SEEMED TOO COLD FOR MOST OF THE FORECAST AREA. GOOD MIXING AND CLEARING SKIES SHOULD PUT TEMPS BACK IN THE 50S FOR THE SOUTHWEST SECTIONS OF THE CWA. .LONG TERM /TONIGHT THROUGH SUNDAY/... ISSUED AT 318 AM CST MON JAN 26 2015 MAIN THEMES FOR THE WEEK CONTINUE TO BE CLOUDS AND MILDER TEMPERATURES THROUGH AT LEAST WEDNESDAY. BY LATE THIS AFTERNOON THE APPROACHING SHORT WAVE SLIDING NEARLY DUE SOUTH TOWARD US WILL BE EAST OF THE REGION WITH THE H500/H700 RIDGE BUILDING INTO THE AREA TONIGHT. ALMOST IMMEDIATELY ANOTHER LEE SIDE TROUGH/BOUNDARY WILL FORM ACROSS THE WESTERN PLAINS AND ENHANCE SOME CLOUDS OVER THE REGION TONIGHT. THIS WILL KEEP TEMPERATURES FROM FALLING TOO FAR WITH RATHER MILD READINGS FOR JANUARY IN THE 20S NORTHEAST TO 30S SOUTH. BY TOMORROW...GENERALLY LIGHT WINDS AT THE SFC AND ALOFT WILL PROMOTE LITTLE MIXING WITH ANY WARMING SOLELY DUE TO INSOLATION. THUS...TEMPERATURES WILL BE SLIGHTLY COOLER THAN TODAY WITH A SUN CLOUD MIX. PATTERN FOR US REMAINS RATHER BENIGN FOR A FEW MORE DAYS...COMPARED TO EAST COAST...AND WE SHOULD BEGIN A NICE WARMING TREND AGAIN LATE TUESDAY NIGHT INTO WEDNESDAY. BETWEEN 06 AND 12Z WED BOTH GFS/00Z EURO INDICATE STRONG WARM AIR ADVECTION WILL STREAM ACROSS MOST OF IOWA. A SFC WAVE IS EXPECTED TO TRACK NEAR OR OVER CENTRAL IOWA KEEPING THE AREA IN THE WARM SECTOR THROUGH THE NOON HOUR. EURO H850 TEMPS WARM CONSIDERABLY TO +10C TO +12C WITH GFS +6C TO +8C THROUGH 18Z WITH SOME COOLING IN THE AFTERNOON FOR BOTH MODELS AS CLOUDS THICKEN. SIMILAR TO JAN 16TH...AM EXPECTING STRONG WARMING TO OUR SOUTHWEST WHICH WILL GENERALLY NOT BE MODIFIED MUCH AS IT MOVES NORTHEAST INTO OUR AREA. GUIDANCE CONTINUES TO LAG WARMTH POTENTIAL AS WITH PREVIOUS SIMILAR EVENT. SUNDAY HIGHS TO OUR SOUTHWEST WERE ALREADY IN THE LOWER TO MID 50S WITH 4C TO 6C H850 TEMPS. HAVE RAISED TMAX FOR WED TO LOWER 40S NORTH TO UPPER 50S SOUTHWEST FOR NOW AND THIS MAY BE TOO COOL. AFTER THE PASSAGE OF THE SFC LOW WED NIGHT ONE COLD FRONT WILL PASS SOUTHEAST BY MORNING WITH A SECONDARY COLD FRONT DRIVING SOUTH THROUGH THE AREA DURING THE DAY WITH A SECOND UPPER LEVEL WAVE. THIS SHOULD RESULT IN CLOUDS AND LIGHT SNOW OR FLURRIES OVER THE EAST DURING THE DAY. ONCE AGAIN EURO H850 WINDS QUITE STRONG WITH 45 TO NEAR 50 KTS EARLY IN THE DAY REMAINING NEAR 45KTS THROUGH EARLY AFTERNOON. LIKELY THAT SUSTAINED WINDS WILL BE NEAR 2O TO 25 MPH WITH GUST POTENTIAL ABOVE 40 KTS. DESPITE THE EURO SHOWING A STRONGER SOLN THAN THE 00Z GFS...GFS BUFR SOUNDINGS CONTINUE TO SUPPORT NEARLY SIMILAR CONDITIONS. WITH SOME UNCERTAINTY AND MINOR DIFFERENCES BETWEEN SOLNS...WILL CONTINUE TO MONITOR OVER THE NEXT FEW MODEL PACKAGES. BREEZY DAY NONE THE LESS. MORE WAVE ENERGY ROTATING SOUTHEAST FROM THE POLAR ANCHOR LOW OVER HUDSON BAY CANADA WILL MOVE SOUTHEAST TOWARD THE GREAT LAKES AND NORTHERN PLAINS BY SATURDAY AND LATE SUNDAY. THERE IS MUCH MORE UNCERTAINTY REGARDING THE EVOLUTION OF THE H500 VORTEX AS IT DEEPENS AND EXPANDS SOUTHEAST TOWARD THE EASTERN CONUS. THE 00Z EURO DROPS ONE ARCTIC FRONT INTO THE AREA SATURDAY WITH A SECOND FRONT AND UPPER LEVEL H500 WAVE BY 12Z SUNDAY. PROGGED H850 TEMPS PLUMMET TO -20C TO -26C MONDAY. NEITHER THE GEM NOR THE GFS OPERATIONAL RUNS SUPPORT THE SAME COLD SOLUTION OF THE EURO FOR NOW WITH THE EXCEPTION OF SOME OF THE MEX GUIDANCE ENSEMBLE GUIDANCE WHICH SUGGEST THE POSSIBILITY OF COLDER TEMPERATURES. IN FACT THE GEM DEVELOPS A DECENT STORM PASSING JUST TO OUR EAST WHILE THE EURO SHEARS THE SYSTEM EAST THROUGH THE SOUTHERN STREAM. WILL NEED TO EVALUATE OVER THE COMING DAYS AND TAKE A MORE MODEST APPROACH TO TEMPERATURES FOR NOW AS PAST TWO NIGHTS THERE HAS BEEN NO CONSISTENCY OVER THE WEEKEND...RESULTING IN LOW CONFIDENCE AT THIS TIME. BETTER CLARITY IS EXPECTED IN THE NEXT DAY OR TWO. && .AVIATION...26/18Z ISSUED AT 1140 AM CST MON JAN 26 2015 IFR/MVFR CIGS CURRENTLY OVER FAR EASTERN IOWA WITH THE WESTERN EDGE NEAR KALO AND KOTM. EXPECT KOTM AND OTHER SITES TO REMAIN VFR THROUGH THE AFTERNOON HOWEVER KALO WILL BE IMPACTED BY THE STRATUS EARLY IN THE PERIOD. ANOTHER ROUND OF STRATUS OVER MINNESOTA WILL ARRIVE TONIGHT. WINDS WILL BECOME WEST TO NW TODAY THEN GRADUALLY SHIFT TO THE NORTHEAST ON TUESDAY. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...PODRAZIK SHORT TERM...PODRAZIK LONG TERM...REV AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS DES MOINES IA
600 AM CST MON JAN 26 2015 ...UPDATED DISCUSSION... .UPDATE... ISSUED AT 558 AM CST MON JAN 26 2015 INTRODUCED PATCHY FZDZ/FLURRIES BETWEEN HIGHWAY 20 TO HIGHWAY 34 AND GENERALLY EAST OF HIGHWAY 169 THROUGH 14Z WITH THE WEAK BAND OF PRECIP QUICKLY MOVING SOUTH THAT IS JUST MOVING INTO THE FORT DODGE AREA AS OF 6 AM. ALGONA AND FOREST CITY REPORTING UP...ONLY CONFIRMING PRECIP IS FINALLY ABLE TO REACH THE SURFACE. SHOULD BE VERY SHORT-LIVED AND LOOKS TO EXIT THE DSM METRO BY 730-8AM. .SHORT TERM /TODAY/... ISSUED AT 318 AM CST MON JAN 26 2015 QUICK MOVING SHORTWAVE LOOKS TO BRING SOME VERY LIGHT SNOW/FZDZ TO NORTHERN AND EASTERN PORTIONS OF THE FORECAST THIS MORNING. TIMING OF ANY PRECIP LOOKS TO BE FROM 10Z TO 14Z WITH SOME LINGERING POPS THROUGH 15Z NEAR THE ALO AREA. LEANED TOWARD A BLEND OF THE NAM12/RAP FOR POPS TODAY AND TOWARDS THE WARMER RAP/ECMWF FOR TEMPS. THE RAP AND NAM MCW/FOD SOUNDINGS HAVE A TOUGH TIME GETTING COMPLETELY SATURATED AS THEY DEPICT A DEEP DRY LAYER BETWEEN 850- 650MB. CERTAINLY SATURATED BELOW 850MB AND ABOVE 650MB...SO SEEDER FEEDER POTENTIAL EXISTS BUT FORCING WITHIN THE DENDRITIC LAYER IS VERY WEAK AND ANY SNOW WILL HAVE A DIFFICULT TIME MAKING IT THROUGH THIS DRY LAYER. IT MAY SNOW FOR A SHORT STINT BY AROUND 12Z-13Z ONCE THE COLUMN COMPLETELY SATURATES NEAR MCW/ALO AREA BUT THE RAP KEEPS THE DRY LAYER THROUGH THE ENTIRE MORNING. AS A RESULT...WITH THE LACK OF ANY ICE INTRODUCTION...HAVE MENTION OF FZDZ THIS MORNING. ONLY A MINOR TRAVEL CONCERN WITH THE FZDZ AS EXPECTING WARMER TEMPERATURES LOOK TO ADVECT IN AND WITH THE VERY QUICK MOVING SHORTWAVE...THE PRECIP SHOULD BE SHORT-LIVED AND SPORADIC AT BEST. PLUS...MUCH OF THE PRECIP RETURNS ON RADAR IN SOUTHERN MINNESOTA ARE NOT REACHING THE GROUND WITH ONLY A COUPLE SPOTS REPORTING -SN ATTM. WAA WILL CONTINUE THROUGH MUCH OF THE MORNING INTO THE EARLY AFTERNOON AND UTILIZED A BLEND OF THE RAP/ECMWF FOR MAX TEMPS TODAY. THE NAM/GFS/SREF SEEMED TOO COLD FOR MOST OF THE FORECAST AREA. GOOD MIXING AND CLEARING SKIES SHOULD PUT TEMPS BACK IN THE 50S FOR THE SOUTHWEST SECTIONS OF THE CWA. .LONG TERM /TONIGHT THROUGH SUNDAY/... ISSUED AT 318 AM CST MON JAN 26 2015 MAIN THEMES FOR THE WEEK CONTINUE TO BE CLOUDS AND MILDER TEMPERATURES THROUGH AT LEAST WEDNESDAY. BY LATE THIS AFTERNOON THE APPROACHING SHORT WAVE SLIDING NEARLY DUE SOUTH TOWARD US WILL BE EAST OF THE REGION WITH THE H500/H700 RIDGE BUILDING INTO THE AREA TONIGHT. ALMOST IMMEDIATELY ANOTHER LEE SIDE TROUGH/BOUNDARY WILL FORM ACROSS THE WESTERN PLAINS AND ENHANCE SOME CLOUDS OVER THE REGION TONIGHT. THIS WILL KEEP TEMPERATURES FROM FALLING TOO FAR WITH RATHER MILD READINGS FOR JANUARY IN THE 20S NORTHEAST TO 30S SOUTH. BY TOMORROW...GENERALLY LIGHT WINDS AT THE SFC AND ALOFT WILL PROMOTE LITTLE MIXING WITH ANY WARMING SOLELY DUE TO INSOLATION. THUS...TEMPERATURES WILL BE SLIGHTLY COOLER THAN TODAY WITH A SUN CLOUD MIX. PATTERN FOR US REMAINS RATHER BENIGN FOR A FEW MORE DAYS...COMPARED TO EAST COAST...AND WE SHOULD BEGIN A NICE WARMING TREND AGAIN LATE TUESDAY NIGHT INTO WEDNESDAY. BETWEEN 06 AND 12Z WED BOTH GFS/00Z EURO INDICATE STRONG WARM AIR ADVECTION WILL STREAM ACROSS MOST OF IOWA. A SFC WAVE IS EXPECTED TO TRACK NEAR OR OVER CENTRAL IOWA KEEPING THE AREA IN THE WARM SECTOR THROUGH THE NOON HOUR. EURO H850 TEMPS WARM CONSIDERABLY TO +10C TO +12C WITH GFS +6C TO +8C THROUGH 18Z WITH SOME COOLING IN THE AFTERNOON FOR BOTH MODELS AS CLOUDS THICKEN. SIMILAR TO JAN 16TH...AM EXPECTING STRONG WARMING TO OUR SOUTHWEST WHICH WILL GENERALLY NOT BE MODIFIED MUCH AS IT MOVES NORTHEAST INTO OUR AREA. GUIDANCE CONTINUES TO LAG WARMTH POTENTIAL AS WITH PREVIOUS SIMILAR EVENT. SUNDAY HIGHS TO OUR SOUTHWEST WERE ALREADY IN THE LOWER TO MID 50S WITH 4C TO 6C H850 TEMPS. HAVE RAISED TMAX FOR WED TO LOWER 40S NORTH TO UPPER 50S SOUTHWEST FOR NOW AND THIS MAY BE TOO COOL. AFTER THE PASSAGE OF THE SFC LOW WED NIGHT ONE COLD FRONT WILL PASS SOUTHEAST BY MORNING WITH A SECONDARY COLD FRONT DRIVING SOUTH THROUGH THE AREA DURING THE DAY WITH A SECOND UPPER LEVEL WAVE. THIS SHOULD RESULT IN CLOUDS AND LIGHT SNOW OR FLURRIES OVER THE EAST DURING THE DAY. ONCE AGAIN EURO H850 WINDS QUITE STRONG WITH 45 TO NEAR 50 KTS EARLY IN THE DAY REMAINING NEAR 45KTS THROUGH EARLY AFTERNOON. LIKELY THAT SUSTAINED WINDS WILL BE NEAR 2O TO 25 MPH WITH GUST POTENTIAL ABOVE 40 KTS. DESPITE THE EURO SHOWING A STRONGER SOLN THAN THE 00Z GFS...GFS BUFR SOUNDINGS CONTINUE TO SUPPORT NEARLY SIMILAR CONDITIONS. WITH SOME UNCERTAINTY AND MINOR DIFFERENCES BETWEEN SOLNS...WILL CONTINUE TO MONITOR OVER THE NEXT FEW MODEL PACKAGES. BREEZY DAY NONE THE LESS. MORE WAVE ENERGY ROTATING SOUTHEAST FROM THE POLAR ANCHOR LOW OVER HUDSON BAY CANADA WILL MOVE SOUTHEAST TOWARD THE GREAT LAKES AND NORTHERN PLAINS BY SATURDAY AND LATE SUNDAY. THERE IS MUCH MORE UNCERTAINTY REGARDING THE EVOLUTION OF THE H500 VORTEX AS IT DEEPENS AND EXPANDS SOUTHEAST TOWARD THE EASTERN CONUS. THE 00Z EURO DROPS ONE ARCTIC FRONT INTO THE AREA SATURDAY WITH A SECOND FRONT AND UPPER LEVEL H500 WAVE BY 12Z SUNDAY. PROGGED H850 TEMPS PLUMMET TO -20C TO -26C MONDAY. NEITHER THE GEM NOR THE GFS OPERATIONAL RUNS SUPPORT THE SAME COLD SOLUTION OF THE EURO FOR NOW WITH THE EXCEPTION OF SOME OF THE MEX GUIDANCE ENSEMBLE GUIDANCE WHICH SUGGEST THE POSSIBILITY OF COLDER TEMPERATURES. IN FACT THE GEM DEVELOPS A DECENT STORM PASSING JUST TO OUR EAST WHILE THE EURO SHEARS THE SYSTEM EAST THROUGH THE SOUTHERN STREAM. WILL NEED TO EVALUATE OVER THE COMING DAYS AND TAKE A MORE MODEST APPROACH TO TEMPERATURES FOR NOW AS PAST TWO NIGHTS THERE HAS BEEN NO CONSISTENCY OVER THE WEEKEND...RESULTING IN LOW CONFIDENCE AT THIS TIME. BETTER CLARITY IS EXPECTED IN THE NEXT DAY OR TWO. && .AVIATION...26/12Z ISSUED AT 558 AM CST MON JAN 26 2015 IFR CIGS WILL QUICKLY DEPART AT MCW THIS MORNING...BUT MVFR CIGS LOOK TO PERSIST THROUGH MUCH OF THE TAF PERIOD. DSM/FOD/OTM LIKELY TO SEE A BREAK IN THE MVFR CIGS THIS AFTERNOON BUT LOW LEVEL MOISTURE MOVES BACK IN WITH THE CAA TONIGHT AND HAVE MENTION OF MVFR CIGS THROUGH THE END OF THE TAF PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...PODRAZIK LONG TERM...REV AVIATION...PODRAZIK UPDATE...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
319 AM CST MON JAN 26 2015 .SHORT TERM /TODAY/... ISSUED AT 318 AM CST MON JAN 26 2015 QUICK MOVING SHORTWAVE LOOKS TO BRING SOME VERY LIGHT SNOW/FZDZ TO NORTHERN AND EASTERN PORTIONS OF THE FORECAST THIS MORNING. TIMING OF ANY PRECIP LOOKS TO BE FROM 10Z TO 14Z WITH SOME LINGERING POPS THROUGH 15Z NEAR THE ALO AREA. LEANED TOWARD A BLEND OF THE NAM12/RAP FOR POPS TODAY AND TOWARDS THE WARMER RAP/ECMWF FOR TEMPS. THE RAP AND NAM MCW/FOD SOUNDINGS HAVE A TOUGH TIME GETTING COMPLETELY SATURATED AS THEY DEPICT A DEEP DRY LAYER BETWEEN 850- 650MB. CERTAINLY SATURATED BELOW 850MB AND ABOVE 650MB...SO SEEDER FEEDER POTENTIAL EXISTS BUT FORCING WITHIN THE DENDRITIC LAYER IS VERY WEAK AND ANY SNOW WILL HAVE A DIFFICULT TIME MAKING IT THROUGH THIS DRY LAYER. IT MAY SNOW FOR A SHORT STINT BY AROUND 12Z-13Z ONCE THE COLUMN COMPLETELY SATURATES NEAR MCW/ALO AREA BUT THE RAP KEEPS THE DRY LAYER THROUGH THE ENTIRE MORNING. AS A RESULT...WITH THE LACK OF ANY ICE INTRODUCTION...HAVE MENTION OF FZDZ THIS MORNING. ONLY A MINOR TRAVEL CONCERN WITH THE FZDZ AS EXPECTING WARMER TEMPERATURES LOOK TO ADVECT IN AND WITH THE VERY QUICK MOVING SHORTWAVE...THE PRECIP SHOULD BE SHORT-LIVED AND SPORADIC AT BEST. PLUS...MUCH OF THE PRECIP RETURNS ON RADAR IN SOUTHERN MINNESOTA ARE NOT REACHING THE GROUND WITH ONLY A COUPLE SPOTS REPORTING -SN ATTM. WAA WILL CONTINUE THROUGH MUCH OF THE MORNING INTO THE EARLY AFTERNOON AND UTILIZED A BLEND OF THE RAP/ECMWF FOR MAX TEMPS TODAY. THE NAM/GFS/SREF SEEMED TOO COLD FOR MOST OF THE FORECAST AREA. GOOD MIXING AND CLEARING SKIES SHOULD PUT TEMPS BACK IN THE 50S FOR THE SOUTHWEST SECTIONS OF THE CWA. .LONG TERM /TONIGHT THROUGH SUNDAY/... ISSUED AT 318 AM CST MON JAN 26 2015 MAIN THEMES FOR THE WEEK CONTINUE TO BE CLOUDS AND MILDER TEMPERATURES THROUGH AT LEAST WEDNESDAY. BY LATE THIS AFTERNOON THE APPROACHING SHORT WAVE SLIDING NEARLY DUE SOUTH TOWARD US WILL BE EAST OF THE REGION WITH THE H500/H700 RIDGE BUILDING INTO THE AREA TONIGHT. ALMOST IMMEDIATELY ANOTHER LEE SIDE TROUGH/BOUNDARY WILL FORM ACROSS THE WESTERN PLAINS AND ENHANCE SOME CLOUDS OVER THE REGION TONIGHT. THIS WILL KEEP TEMPERATURES FROM FALLING TOO FAR WITH RATHER MILD READINGS FOR JANUARY IN THE 20S NORTHEAST TO 30S SOUTH. BY TOMORROW...GENERALLY LIGHT WINDS AT THE SFC AND ALOFT WILL PROMOTE LITTLE MIXING WITH ANY WARMING SOLELY DUE TO INSOLATION. THUS...TEMPERATURES WILL BE SLIGHTLY COOLER THAN TODAY WITH A SUN CLOUD MIX. PATTERN FOR US REMAINS RATHER BENIGN FOR A FEW MORE DAYS...COMPARED TO EAST COAST...AND WE SHOULD BEGIN A NICE WARMING TREND AGAIN LATE TUESDAY NIGHT INTO WEDNESDAY. BETWEEN 06 AND 12Z WED BOTH GFS/00Z EURO INDICATE STRONG WARM AIR ADVECTION WILL STREAM ACROSS MOST OF IOWA. A SFC WAVE IS EXPECTED TO TRACK NEAR OR OVER CENTRAL IOWA KEEPING THE AREA IN THE WARM SECTOR THROUGH THE NOON HOUR. EURO H850 TEMPS WARM CONSIDERABLY TO +10C TO +12C WITH GFS +6C TO +8C THROUGH 18Z WITH SOME COOLING IN THE AFTERNOON FOR BOTH MODELS AS CLOUDS THICKEN. SIMILAR TO JAN 16TH...AM EXPECTING STRONG WARMING TO OUR SOUTHWEST WHICH WILL GENERALLY NOT BE MODIFIED MUCH AS IT MOVES NORTHEAST INTO OUR AREA. GUIDANCE CONTINUES TO LAG WARMTH POTENTIAL AS WITH PREVIOUS SIMILAR EVENT. SUNDAY HIGHS TO OUR SOUTHWEST WERE ALREADY IN THE LOWER TO MID 50S WITH 4C TO 6C H850 TEMPS. HAVE RAISED TMAX FOR WED TO LOWER 40S NORTH TO UPPER 50S SOUTHWEST FOR NOW AND THIS MAY BE TOO COOL. AFTER THE PASSAGE OF THE SFC LOW WED NIGHT ONE COLD FRONT WILL PASS SOUTHEAST BY MORNING WITH A SECONDARY COLD FRONT DRIVING SOUTH THROUGH THE AREA DURING THE DAY WITH A SECOND UPPER LEVEL WAVE. THIS SHOULD RESULT IN CLOUDS AND LIGHT SNOW OR FLURRIES OVER THE EAST DURING THE DAY. ONCE AGAIN EURO H850 WINDS QUITE STRONG WITH 45 TO NEAR 50 KTS EARLY IN THE DAY REMAINING NEAR 45KTS THROUGH EARLY AFTERNOON. LIKELY THAT SUSTAINED WINDS WILL BE NEAR 2O TO 25 MPH WITH GUST POTENTIAL ABOVE 40 KTS. DESPITE THE EURO SHOWING A STRONGER SOLN THAN THE 00Z GFS...GFS BUFR SOUNDINGS CONTINUE TO SUPPORT NEARLY SIMILAR CONDITIONS. WITH SOME UNCERTAINTY AND MINOR DIFFERENCES BETWEEN SOLNS...WILL CONTINUE TO MONITOR OVER THE NEXT FEW MODEL PACKAGES. BREEZY DAY NONE THE LESS. MORE WAVE ENERGY ROTATING SOUTHEAST FROM THE POLAR ANCHOR LOW OVER HUDSON BAY CANADA WILL MOVE SOUTHEAST TOWARD THE GREAT LAKES AND NORTHERN PLAINS BY SATURDAY AND LATE SUNDAY. THERE IS MUCH MORE UNCERTAINTY REGARDING THE EVOLUTION OF THE H500 VORTEX AS IT DEEPENS AND EXPANDS SOUTHEAST TOWARD THE EASTERN CONUS. THE 00Z EURO DROPS ONE ARCTIC FRONT INTO THE AREA SATURDAY WITH A SECOND FRONT AND UPPER LEVEL H500 WAVE BY 12Z SUNDAY. PROGGED H850 TEMPS PLUMMET TO -20C TO -26C MONDAY. NEITHER THE GEM NOR THE GFS OPERATIONAL RUNS SUPPORT THE SAME COLD SOLUTION OF THE EURO FOR NOW WITH THE EXCEPTION OF SOME OF THE MEX GUIDANCE ENSEMBLE GUIDANCE WHICH SUGGEST THE POSSIBILITY OF COLDER TEMPERATURES. IN FACT THE GEM DEVELOPS A DECENT STORM PASSING JUST TO OUR EAST WHILE THE EURO SHEARS THE SYSTEM EAST THROUGH THE SOUTHERN STREAM. WILL NEED TO EVALUATE OVER THE COMING DAYS AND TAKE A MORE MODEST APPROACH TO TEMPERATURES FOR NOW AS PAST TWO NIGHTS THERE HAS BEEN NO CONSISTENCY OVER THE WEEKEND...RESULTING IN LOW CONFIDENCE AT THIS TIME. BETTER CLARITY IS EXPECTED IN THE NEXT DAY OR TWO. && .AVIATION...26/06Z ISSUED AT 1133 PM CST SUN JAN 25 2015 LOW STRATUS WILL KEEP LOW MVFR CEILINGS AT SITES THROUGH MOST OF PERIOD. NORTHER SITES...KMCW AND KALO MAY SEE CEILINGS DROP TO IFR BRIEFLY BETWEEN 06Z-12Z AS SYSTEM PUSHES SOUTH. HOWEVER...BELIEVE IFR CEILINGS WILL BE BRIEF. WESTERN SITES KFOD AND KDSM WILL SEE IMPROVEMENT TO VFR NEAR 18Z...THOUGH EASTERN SITES WILL REMAIN MVFR THROUGH MOST OF PERIOD...LIFTING NEAR 00Z...THOUGH MAY HAVE BEEN TOO OPTIMISTIC WITH IMPROVEMENT OF CEILINGS. WINDS WILL SHIFT TO THE NORTHWEST BY 18Z AND WILL BE STRONG...NEAR 15 KTS THROUGH AFTERNOON AT SITES. && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PODRAZIK LONG TERM...REV AVIATION...AWB
AREA FORECAST DISCUSSION
NWS JACKSON KY
110 PM EST MON JAN 26 2015 .UPDATE... ISSUED AT 1155 AM EST MON JAN 26 2015 THE BAND OF STEADIER SNOW CONTINUES TO WORK ACROSS THE SOUTHEASTERN COUNTIES WITH SOME LIGHT SNOW AND FLURRIES ON UPSLOPE FLOW/INSTABILITY LINGERING BEHIND THIS. SOME OF THIS LIGHTER SNOW AND FLURRIES ARE BELOW THE RADAR BEAM...SO THE AREAL EXTENT AT THIS TIME MAY BE A BIT GREATER THAN INDICATED BY RADAR. THE TEMPERATURES ARE GENERALLY RUNNING BELOW GUIDANCE ONCE THE COLDER AIR MOVES IN AND WE CURRENTLY EXPECT TEMPERATURES TO RECOVER ONLY A DEGREE OR TWO THE REMAINDER OF THE DAY...SO NEARLY STEADY TEMPERATURES ARE EXPECTED IN MOST PLACES...WITH A BUMP DOWN IN THE DEEPEST VALLEYS IN THE FAR SOUTHEAST AND THEN NEARLY STEADY FOR THE REST OF THE DAY. NORTHWEST FLOW AN ADDITIONAL DISTURBANCES PASSING BY WILL LEAD TO ISOLATED TO SCATTERED SNOW SHOWERS AND FLURRIES THROUGH AT LEAST TONIGHT. ADDITIONAL SNOW ACCUMULATIONS WILL BE LIGHT GENERALLY LESS THAN A HALF OF AN INCH. HOWEVER...THE NEARLY STEADY TEMPERATURES BELOW FREEZING AND SOME LIGHT FALLING PRECIP SHOULD ACT TO COOL ROADWAYS AND SURFACES AND SLICK OR REFREEZE SPOTS ARE ANTICIPATED AT TIMES ESPECIALLY ON ANY UNTREATED LOCATIONS. THESE COULD BECOME MORE PREVALENT BY DARK...DEPENDING ON WHERE SNOW SHOWERS AND FLURRIES OCCUR. AN SPS HAS BEEN REISSUED TO HANDLE THIS AND GRAPHICAL NOWCASTS WILL CONTINUE TO BE ISSUED THIS AFTERNOON TO ADDRESS THIS. UPDATE ISSUED AT 647 AM EST MON JAN 26 2015 WSR-88D RADAR SHOWS A FEW SHOWERS AND SNOW SHOWERS MOVING ACROSS THE REGION THE MORNING AS CLIPPER LOW CONTINUES TO PROGRESS ACROSS EASTERN KY. THE TEMPERATURES HAVE BEEN TRICKY OVERNIGHT INTO THIS MORNING AS COLDER AIR CONTINUES TO SLOWLY ADVECT FROM NW TO SE THIS MORNING. FRESHENED UP GRIDS WITH LATEST OBS AND TRENDS THIS MORNING INCLUDING A QUICK UPDATE OF WX GRIDS TO BETTER SHOW TRANSITION THIS MORNING. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 342 AM EST MON JAN 26 2015 WSR-88D THIS MORNING HAS CONTINUED TO SHOW AREAS OF RAIN SHOWERS MOVING ACROSS EASTERN KY THIS MORNING. BEST COVERAGE HAS GENERALLY BEEN ACROSS THE FAR SOUTHERN PORTIONS OF THE REGION THIS MORNING. HOWEVER THIS MORNING WE HAVE SEEN GENERALLY LOWER AMTS OF PRECIP AND TEMPS ARE STILL ABOVE FREEZING AT MOST LOCATIONS BESIDE BLACK MTN AT 8Z. GIVEN THIS HAVE LESSEN POPS AND ALSO LESSENED QPF AMTS ACROSS THE REGION. THIS MAY STILL BE TOO OPTIMISTIC AS RETURNS FROM RADAR HAVE BEEN QUITE LOW ACROSS CENTRAL AND WESTERN KY THIS MORNING. THIS TREND OF LOWERING REFLECTIVITIES IS ALSO BACK UP BY THE HRRR WHICH ALSO INITIALIZED FAIRLY WELL AT 7Z. OTHERWISE LEFT OVER SHOWERS WILL SLOWLY TRANSITION TO SNOW SHOWERS THROUGH THE DAY WITH BEST COVERAGE ACROSS THE FAR EAST THIS AFTERNOON. THIS SURFACE LOW AND UPPER LEVEL TROUGH WILL CONTINUE EXIT EAST WHERE IT DEVELOPS INTO A STRONG NOREASTER ALONG THE ATLANTIC SEABOARD LATER TODAY. ACROSS EASTERN KY WE WILL CONTINUE TO TRANSITION TO GENERALLY WEST TO NW FLOW. MODELS DO SHOW A FETCH OF MOISTURE DROPPING SOUTH FROM THE GREAT LAKES TONIGHT INTO TUESDAY. RIGHT NOW HAVE MOVED TOWARD SLIGHT CHANCES OF SNOW SHOWERS MAINLY ACROSS SW PORTION OF THE CWA WHERE BETTER PLACEMENT OF MOISTURE AXIS EXISTS. EVEN SO GENERALLY MOSTLY CLOUDY CONDITIONS WILL PREVAIL FOR MUCH OF THE PERIOD AREA WIDE COUPLED WITH GENERALLY BELOW NORMAL TEMPS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 445 AM EST MON JAN 26 2015 THE MODELS ARE IN GOOD AGREEMENT ALOFT FOR THE FIRST PART OF THE EXTENDED AND ARE IN FAIR AGREEMENT WITH THE LATTER PART. THE RUB HERE IS THAT THE CONSISTENCY HAS BEEN TAKING HITS LATELY WITH THE FORECAST FOR NEXT WEEKEND. A ONCE DISCARDED SOLUTION...MAINLY SEEN EARLIER IN THE GFS...HAS RETURNED WITH SOME LIMITED SUPPORT FROM THE ECMWF. EARLY ON...THE FOCUS WILL BE ON A DEEP CYCLONE OFF THE EASTERN SEABOARD WHILE A FAST FLOW OF ENERGY ROILS ABOVE EAST KENTUCKY ON A GENERALLY NORTHWEST TO SOUTHEAST PATH INTO WEDNESDAY MORNING. THIS VORT STREAM IS SHUNTED EAST BY MIDDAY WEDNESDAY AS HIGHER HEIGHTS FROM A WEAKENING SOUTHERN RIDGE MOVES INTO THE MID MISSISSIPPI VALLEY AND THEN OVER THE LOWER OHIO BASIN. AT THE SAME TIME...A DEVELOPING TROUGH WILL DIP INTO THE CENTRAL PLAINS AND SLIDE EAST. THIS FEATURE RAMPS UP INTO THE DAY THURSDAY WITH THE GFS PROVIDING BETTER SUPPORT FOR THE MORE ROBUST SOLUTION OF THE ECMWF. THIS TROUGH CROSSES EAST KENTUCKY LATER THURSDAY NIGHT WITH FLAT FLOW TO FOLLOW. HOWEVER...OVER THE SOUTHWEST PARTS OF THE NATION A LARGE CLOSED LOW IN THE SOUTHERN STREAM IS NOW DEPICTED...PARTICULARLY BY THE LATEST ECMWF...OPENING UP AND SPILLING ITS ENERGY EAST INTO THE FLOW RIDING OVER THE TENNESSEE VALLEY. THE MODELS NOW SHOW SOME CONNECTION TO THE NORTHERN AND SOUTHERN STREAMS WHICH WOULD CERTAINLY MAKE THINGS MORE INTERESTING FOR THE UPCOMING WEEKEND IF THAT PANS OUT. FOR NOW...WILL SHOW ONLY LIMITED INTERACTION AND EASE INTO A MORE DYNAMIC SCENARIO GIVEN THE UNCERTAINTY AND LACK OF MODEL RUN TO RUN CONSISTENCY WITH THIS PART OF THE FORECAST. IN GENERAL...A BLEND OF THE MODELS WAS PREFERRED THROUGH THE BULK OF THE FORECAST WITH SOME ADJUSTMENT TOWARD THE PREVIOUS FORECAST FOR NEXT WEEKEND GIVEN THE CONSISTENCY CONCERNS. SENSIBLE WEATHER WILL FEATURE THE ENDING OF THE UPSLOPE SNOW SHOWERS/FLURRIES IN THE FAR EAST EARLY WEDNESDAY MORNING WITH SOME SUNSHINE RETURNING. THE NEXT CLIPPER SYSTEM WILL THEN MOVE INTO THE OHIO VALLEY ON THURSDAY WITH A CHANCE FOR RAIN AND SNOW ACROSS THE AREA INTO FRIDAY MORNING. ONLY A BRIEF WINDOW FOR DRYING CAN BE EXPECTED FROM FRIDAY NIGHT INTO SATURDAY MORNING BEFORE THE POTENTIAL FOR MAINLY SNOW ARRIVES FROM THE SOUTHWEST IN FAST LOW AND MID LEVEL FLOW RIDING ALONG A WEST TO EAST ARCTIC BOUNDARY LYING OVER THE OHIO VALLEY. THIS BOUNDARY IS EXPECTED TO PUSH ON THROUGH KENTUCKY BY SUNDAY MORNING WITH SNOW CHANCES CONTINUING...MAINLY IN THE SOUTHERN PARTS OF THE CWA. THIS SETUP WILL NEED TO BE WATCHED CLOSELY... THOUGH...AS THE POTENTIAL EXISTS FOR THE COLD AIR TO SETTLE INTO THE STATE BY LATE IN THE WEEKEND AND A LOW TO FORM IN THE NORTHERN GULF SLIDING NORTHEAST WHILE SENDING AMPLE MOISTURE NORTH INTO OUR AREA ON THE COLD SIDE OF THIS ARCTIC BOUNDARY. FOR NOW...HAVE GONE WITH JUST SMALL CHANCES FOR SNOW FROM SATURDAY AFTERNOON THROUGH SUNDAY... BUT THAT WILL SURELY NEED TO BE ADJUSTED ONE WAY OR ANOTHER AS THE MODELS GET A BETTER HANDLE ON THIS SITUATION IN FUTURE RUNS. THE CR GRID LOAD MADE FOR AN OKAY START TO THE EXTENDED FORECAST GRIDS WITH CHANGES MADE PRIMARILY TO BETTER REFLECT THE LATEST ECMWF SOLUTION FOR THE UPCOMING WEEKEND. ALSO...MADE SOME TYPICAL RIDGE AND VALLEY TEMPERATURE ADJUSTMENTS FOR LOWS EACH NIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 109 PM EST MON JAN 26 2015 EXPECT VARYING CIGS THROUGH THE EVENING AND INTO TONIGHT AS SOME UPSLOPE SNOW SHOWERS CONTINUE TO MOVE THROUGH THE AREA. WITH THIS...ACTIVITY...CIGS WILL GENERALLY BE AT AIRFIELD MINS OR JUST ABOVE FOR THE TAF SITES. VISIBILITY REDUCTIONS WILL BE SHORT IN DURATION DUE TO THE SHOWERY NATURE OF THE SNOW SHOWERS THIS EVENING. A BRIEF BREAK IN THE ACTIVITY WILL OCCUR AROUND 00Z THROUGH 06Z TONIGHT BEFORE THE NEXT SHORT WAVE MOVES THROUGH AND BRINGS ANOTHER ROUND OF SNOW SHOWERS TUESDAY MORNING INTO THE AFTERNOON. WINDS WILL GENERALLY BE OUT OF THE WEST AND NORTHWEST THROUGH THE PERIOD WITH SOME GUSTS TO 20 KNOTS AT TIMES THROUGH THIS EVENING AND TONIGHT. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...DJ LONG TERM...GREIF AVIATION...JVM/SHALLENBERGER
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1205 PM EST MON JAN 26 2015 .UPDATE... ISSUED AT 1155 AM EST MON JAN 26 2015 THE BAND OF STEADIER SNOW CONTINUES TO WORK ACROSS THE SOUTHEASTERN COUNTIES WITH SOME LIGHT SNOW AND FLURRIES ON UPSLOPE FLOW/INSTABILITY LINGERING BEHIND THIS. SOME OF THIS LIGHTER SNOW AND FLURRIES ARE BELOW THE RADAR BEAM...SO THE AREAL EXTENT AT THIS TIME MAY BE A BIT GREATER THAN INDICATED BY RADAR. THE TEMPERATURES ARE GENERALLY RUNNING BELOW GUIDANCE ONCE THE COLDER AIR MOVES IN AND WE CURRENTLY EXPECT TEMPERATURES TO RECOVER ONLY A DEGREE OR TWO THE REMAINDER OF THE DAY...SO NEARLY STEADY TEMPERATURES ARE EXPECTED IN MOST PLACES...WITH A BUMP DOWN IN THE DEEPEST VALLEYS IN THE FAR SOUTHEAST AND THEN NEARLY STEADY FOR THE REST OF THE DAY. NORTHWEST FLOW AN ADDITIONAL DISTURBANCES PASSING BY WILL LEAD TO ISOLATED TO SCATTERED SNOW SHOWERS AND FLURRIES THROUGH AT LEAST TONIGHT. ADDITIONAL SNOW ACCUMULATIONS WILL BE LIGHT GENERALLY LESS THAN A HALF OF AN INCH. HOWEVER...THE NEARLY STEADY TEMPERATURES BELOW FREEZING AND SOME LIGHT FALLING PRECIP SHOULD ACT TO COOL ROADWAYS AND SURFACES AND SLICK OR REFREEZE SPOTS ARE ANTICIPATED AT TIMES ESPECIALLY ON ANY UNTREATED LOCATIONS. THESE COULD BECOME MORE PREVALENT BY DARK...DEPENDING ON WHERE SNOW SHOWERS AND FLURRIES OCCUR. AN SPS HAS BEEN REISSUED TO HANDLE THIS AND GRAPHICAL NOWCASTS WILL CONTINUE TO BE ISSUED THIS AFTERNOON TO ADDRESS THIS. UPDATE ISSUED AT 647 AM EST MON JAN 26 2015 WSR-88D RADAR SHOWS A FEW SHOWERS AND SNOW SHOWERS MOVING ACROSS THE REGION THE MORNING AS CLIPPER LOW CONTINUES TO PROGRESS ACROSS EASTERN KY. THE TEMPERATURES HAVE BEEN TRICKY OVERNIGHT INTO THIS MORNING AS COLDER AIR CONTINUES TO SLOWLY ADVECT FROM NW TO SE THIS MORNING. FRESHENED UP GRIDS WITH LATEST OBS AND TRENDS THIS MORNING INCLUDING A QUICK UPDATE OF WX GRIDS TO BETTER SHOW TRANSITION THIS MORNING. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 342 AM EST MON JAN 26 2015 WSR-88D THIS MORNING HAS CONTINUED TO SHOW AREAS OF RAIN SHOWERS MOVING ACROSS EASTERN KY THIS MORNING. BEST COVERAGE HAS GENERALLY BEEN ACROSS THE FAR SOUTHERN PORTIONS OF THE REGION THIS MORNING. HOWEVER THIS MORNING WE HAVE SEEN GENERALLY LOWER AMTS OF PRECIP AND TEMPS ARE STILL ABOVE FREEZING AT MOST LOCATIONS BESIDE BLACK MTN AT 8Z. GIVEN THIS HAVE LESSEN POPS AND ALSO LESSENED QPF AMTS ACROSS THE REGION. THIS MAY STILL BE TOO OPTIMISTIC AS RETURNS FROM RADAR HAVE BEEN QUITE LOW ACROSS CENTRAL AND WESTERN KY THIS MORNING. THIS TREND OF LOWERING REFLECTIVITIES IS ALSO BACK UP BY THE HRRR WHICH ALSO INITIALIZED FAIRLY WELL AT 7Z. OTHERWISE LEFT OVER SHOWERS WILL SLOWLY TRANSITION TO SNOW SHOWERS THROUGH THE DAY WITH BEST COVERAGE ACROSS THE FAR EAST THIS AFTERNOON. THIS SURFACE LOW AND UPPER LEVEL TROUGH WILL CONTINUE EXIT EAST WHERE IT DEVELOPS INTO A STRONG NOREASTER ALONG THE ATLANTIC SEABOARD LATER TODAY. ACROSS EASTERN KY WE WILL CONTINUE TO TRANSITION TO GENERALLY WEST TO NW FLOW. MODELS DO SHOW A FETCH OF MOISTURE DROPPING SOUTH FROM THE GREAT LAKES TONIGHT INTO TUESDAY. RIGHT NOW HAVE MOVED TOWARD SLIGHT CHANCES OF SNOW SHOWERS MAINLY ACROSS SW PORTION OF THE CWA WHERE BETTER PLACEMENT OF MOISTURE AXIS EXISTS. EVEN SO GENERALLY MOSTLY CLOUDY CONDITIONS WILL PREVAIL FOR MUCH OF THE PERIOD AREA WIDE COUPLED WITH GENERALLY BELOW NORMAL TEMPS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 445 AM EST MON JAN 26 2015 THE MODELS ARE IN GOOD AGREEMENT ALOFT FOR THE FIRST PART OF THE EXTENDED AND ARE IN FAIR AGREEMENT WITH THE LATTER PART. THE RUB HERE IS THAT THE CONSISTENCY HAS BEEN TAKING HITS LATELY WITH THE FORECAST FOR NEXT WEEKEND. A ONCE DISCARDED SOLUTION...MAINLY SEEN EARLIER IN THE GFS...HAS RETURNED WITH SOME LIMITED SUPPORT FROM THE ECMWF. EARLY ON...THE FOCUS WILL BE ON A DEEP CYCLONE OFF THE EASTERN SEABOARD WHILE A FAST FLOW OF ENERGY ROILS ABOVE EAST KENTUCKY ON A GENERALLY NORTHWEST TO SOUTHEAST PATH INTO WEDNESDAY MORNING. THIS VORT STREAM IS SHUNTED EAST BY MIDDAY WEDNESDAY AS HIGHER HEIGHTS FROM A WEAKENING SOUTHERN RIDGE MOVES INTO THE MID MISSISSIPPI VALLEY AND THEN OVER THE LOWER OHIO BASIN. AT THE SAME TIME...A DEVELOPING TROUGH WILL DIP INTO THE CENTRAL PLAINS AND SLIDE EAST. THIS FEATURE RAMPS UP INTO THE DAY THURSDAY WITH THE GFS PROVIDING BETTER SUPPORT FOR THE MORE ROBUST SOLUTION OF THE ECMWF. THIS TROUGH CROSSES EAST KENTUCKY LATER THURSDAY NIGHT WITH FLAT FLOW TO FOLLOW. HOWEVER...OVER THE SOUTHWEST PARTS OF THE NATION A LARGE CLOSED LOW IN THE SOUTHERN STREAM IS NOW DEPICTED...PARTICULARLY BY THE LATEST ECMWF...OPENING UP AND SPILLING ITS ENERGY EAST INTO THE FLOW RIDING OVER THE TENNESSEE VALLEY. THE MODELS NOW SHOW SOME CONNECTION TO THE NORTHERN AND SOUTHERN STREAMS WHICH WOULD CERTAINLY MAKE THINGS MORE INTERESTING FOR THE UPCOMING WEEKEND IF THAT PANS OUT. FOR NOW...WILL SHOW ONLY LIMITED INTERACTION AND EASE INTO A MORE DYNAMIC SCENARIO GIVEN THE UNCERTAINTY AND LACK OF MODEL RUN TO RUN CONSISTENCY WITH THIS PART OF THE FORECAST. IN GENERAL...A BLEND OF THE MODELS WAS PREFERRED THROUGH THE BULK OF THE FORECAST WITH SOME ADJUSTMENT TOWARD THE PREVIOUS FORECAST FOR NEXT WEEKEND GIVEN THE CONSISTENCY CONCERNS. SENSIBLE WEATHER WILL FEATURE THE ENDING OF THE UPSLOPE SNOW SHOWERS/FLURRIES IN THE FAR EAST EARLY WEDNESDAY MORNING WITH SOME SUNSHINE RETURNING. THE NEXT CLIPPER SYSTEM WILL THEN MOVE INTO THE OHIO VALLEY ON THURSDAY WITH A CHANCE FOR RAIN AND SNOW ACROSS THE AREA INTO FRIDAY MORNING. ONLY A BRIEF WINDOW FOR DRYING CAN BE EXPECTED FROM FRIDAY NIGHT INTO SATURDAY MORNING BEFORE THE POTENTIAL FOR MAINLY SNOW ARRIVES FROM THE SOUTHWEST IN FAST LOW AND MID LEVEL FLOW RIDING ALONG A WEST TO EAST ARCTIC BOUNDARY LYING OVER THE OHIO VALLEY. THIS BOUNDARY IS EXPECTED TO PUSH ON THROUGH KENTUCKY BY SUNDAY MORNING WITH SNOW CHANCES CONTINUING...MAINLY IN THE SOUTHERN PARTS OF THE CWA. THIS SETUP WILL NEED TO BE WATCHED CLOSELY... THOUGH...AS THE POTENTIAL EXISTS FOR THE COLD AIR TO SETTLE INTO THE STATE BY LATE IN THE WEEKEND AND A LOW TO FORM IN THE NORTHERN GULF SLIDING NORTHEAST WHILE SENDING AMPLE MOISTURE NORTH INTO OUR AREA ON THE COLD SIDE OF THIS ARCTIC BOUNDARY. FOR NOW...HAVE GONE WITH JUST SMALL CHANCES FOR SNOW FROM SATURDAY AFTERNOON THROUGH SUNDAY... BUT THAT WILL SURELY NEED TO BE ADJUSTED ONE WAY OR ANOTHER AS THE MODELS GET A BETTER HANDLE ON THIS SITUATION IN FUTURE RUNS. THE CR GRID LOAD MADE FOR AN OKAY START TO THE EXTENDED FORECAST GRIDS WITH CHANGES MADE PRIMARILY TO BETTER REFLECT THE LATEST ECMWF SOLUTION FOR THE UPCOMING WEEKEND. ALSO...MADE SOME TYPICAL RIDGE AND VALLEY TEMPERATURE ADJUSTMENTS FOR LOWS EACH NIGHT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 632 AM EST MON JAN 26 2015 MOST SITES HAVE COME DOWN THIS MORNING TO IFR AND LIFR CONDITIONS. A FEW SITES ARE SEEING LOWER VIS DUE TO FOG AND/OR SHOWER ACTIVITY MOVING ACROSS THOSE SITES. COLDER AIR IS SLOWING MOVING INTO THE REGION THIS MORNING AND WILL TRANSITION RAIN SHOWERS TO SNOW SHOWERS AS WE GO THROUGH THE MORNING. OTHERWISE A FEW SITES ARE SEEING GUSTY WINDS AROUND 15 TO 20 KTS AS WINDS BEGIN SWITCHING WEST TO NORTHWEST THROUGH THE DAY AS LOW CONTINUES TO EXIT TO THE EAST. OTHERWISE SITES ARE EXPECTED TO IMPROVE LATER THIS AFTERNOON AS DRIER AIR CONTINUES TO FILTER INTO EASTERN KY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...DJ LONG TERM...GREIF AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
648 AM EST MON JAN 26 2015 .UPDATE... ISSUED AT 647 AM EST MON JAN 26 2015 WSR-88D RADAR SHOWS A FEW SHOWERS AND SNOW SHOWERS MOVING ACROSS THE REGION THE MORNING AS CLIPPER LOW CONTINUES TO PROGRESS ACROSS EASTERN KY. THE TEMPERATURES HAVE BEEN TRICKY OVERNIGHT INTO THIS MORNING AS COLDER AIR CONTINUES TO SLOWLY ADVECT FROM NW TO SE THIS MORNING. FRESHENED UP GRIDS WITH LATEST OBS AND TRENDS THIS MORNING INCLUDING A QUICK UPDATE OF WX GRIDS TO BETTER SHOW TRANSITION THIS MORNING. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 342 AM EST MON JAN 26 2015 WSR-88D THIS MORNING HAS CONTINUED TO SHOW AREAS OF RAIN SHOWERS MOVING ACROSS EASTERN KY THIS MORNING. BEST COVERAGE HAS GENERALLY BEEN ACROSS THE FAR SOUTHERN PORTIONS OF THE REGION THIS MORNING. HOWEVER THIS MORNING WE HAVE SEEN GENERALLY LOWER AMTS OF PRECIP AND TEMPS ARE STILL ABOVE FREEZING AT MOST LOCATIONS BESIDE BLACK MTN AT 8Z. GIVEN THIS HAVE LESSEN POPS AND ALSO LESSENED QPF AMTS ACROSS THE REGION. THIS MAY STILL BE TOO OPTIMISTIC AS RETURNS FROM RADAR HAVE BEEN QUITE LOW ACROSS CENTRAL AND WESTERN KY THIS MORNING. THIS TREND OF LOWERING REFLECTIVITIES IS ALSO BACK UP BY THE HRRR WHICH ALSO INITIALIZED FAIRLY WELL AT 7Z. OTHERWISE LEFT OVER SHOWERS WILL SLOWLY TRANSITION TO SNOW SHOWERS THROUGH THE DAY WITH BEST COVERAGE ACROSS THE FAR EAST THIS AFTERNOON. THIS SURFACE LOW AND UPPER LEVEL TROUGH WILL CONTINUE EXIT EAST WHERE IT DEVELOPS INTO A STRONG NOREASTER ALONG THE ATLANTIC SEABOARD LATER TODAY. ACROSS EASTERN KY WE WILL CONTINUE TO TRANSITION TO GENERALLY WEST TO NW FLOW. MODELS DO SHOW A FETCH OF MOISTURE DROPPING SOUTH FROM THE GREAT LAKES TONIGHT INTO TUESDAY. RIGHT NOW HAVE MOVED TOWARD SLIGHT CHANCES OF SNOW SHOWERS MAINLY ACROSS SW PORTION OF THE CWA WHERE BETTER PLACEMENT OF MOISTURE AXIS EXISTS. EVEN SO GENERALLY MOSTLY CLOUDY CONDITIONS WILL PREVAIL FOR MUCH OF THE PERIOD AREA WIDE COUPLED WITH GENERALLY BELOW NORMAL TEMPS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 445 AM EST MON JAN 26 2015 THE MODELS ARE IN GOOD AGREEMENT ALOFT FOR THE FIRST PART OF THE EXTENDED AND ARE IN FAIR AGREEMENT WITH THE LATTER PART. THE RUB HERE IS THAT THE CONSISTENCY HAS BEEN TAKING HITS LATELY WITH THE FORECAST FOR NEXT WEEKEND. A ONCE DISCARDED SOLUTION...MAINLY SEEN EARLIER IN THE GFS...HAS RETURNED WITH SOME LIMITED SUPPORT FROM THE ECMWF. EARLY ON...THE FOCUS WILL BE ON A DEEP CYCLONE OFF THE EASTERN SEABOARD WHILE A FAST FLOW OF ENERGY ROILS ABOVE EAST KENTUCKY ON A GENERALLY NORTHWEST TO SOUTHEAST PATH INTO WEDNESDAY MORNING. THIS VORT STREAM IS SHUNTED EAST BY MIDDAY WEDNESDAY AS HIGHER HEIGHTS FROM A WEAKENING SOUTHERN RIDGE MOVES INTO THE MID MISSISSIPPI VALLEY AND THEN OVER THE LOWER OHIO BASIN. AT THE SAME TIME...A DEVELOPING TROUGH WILL DIP INTO THE CENTRAL PLAINS AND SLIDE EAST. THIS FEATURE RAMPS UP INTO THE DAY THURSDAY WITH THE GFS PROVIDING BETTER SUPPORT FOR THE MORE ROBUST SOLUTION OF THE ECMWF. THIS TROUGH CROSSES EAST KENTUCKY LATER THURSDAY NIGHT WITH FLAT FLOW TO FOLLOW. HOWEVER...OVER THE SOUTHWEST PARTS OF THE NATION A LARGE CLOSED LOW IN THE SOUTHERN STREAM IS NOW DEPICTED...PARTICULARLY BY THE LATEST ECMWF...OPENING UP AND SPILLING ITS ENERGY EAST INTO THE FLOW RIDING OVER THE TENNESSEE VALLEY. THE MODELS NOW SHOW SOME CONNECTION TO THE NORTHERN AND SOUTHERN STREAMS WHICH WOULD CERTAINLY MAKE THINGS MORE INTERESTING FOR THE UPCOMING WEEKEND IF THAT PANS OUT. FOR NOW...WILL SHOW ONLY LIMITED INTERACTION AND EASE INTO A MORE DYNAMIC SCENARIO GIVEN THE UNCERTAINTY AND LACK OF MODEL RUN TO RUN CONSISTENCY WITH THIS PART OF THE FORECAST. IN GENERAL...A BLEND OF THE MODELS WAS PREFERRED THROUGH THE BULK OF THE FORECAST WITH SOME ADJUSTMENT TOWARD THE PREVIOUS FORECAST FOR NEXT WEEKEND GIVEN THE CONSISTENCY CONCERNS. SENSIBLE WEATHER WILL FEATURE THE ENDING OF THE UPSLOPE SNOW SHOWERS/FLURRIES IN THE FAR EAST EARLY WEDNESDAY MORNING WITH SOME SUNSHINE RETURNING. THE NEXT CLIPPER SYSTEM WILL THEN MOVE INTO THE OHIO VALLEY ON THURSDAY WITH A CHANCE FOR RAIN AND SNOW ACROSS THE AREA INTO FRIDAY MORNING. ONLY A BRIEF WINDOW FOR DRYING CAN BE EXPECTED FROM FRIDAY NIGHT INTO SATURDAY MORNING BEFORE THE POTENTIAL FOR MAINLY SNOW ARRIVES FROM THE SOUTHWEST IN FAST LOW AND MID LEVEL FLOW RIDING ALONG A WEST TO EAST ARCTIC BOUNDARY LYING OVER THE OHIO VALLEY. THIS BOUNDARY IS EXPECTED TO PUSH ON THROUGH KENTUCKY BY SUNDAY MORNING WITH SNOW CHANCES CONTINUING...MAINLY IN THE SOUTHERN PARTS OF THE CWA. THIS SETUP WILL NEED TO BE WATCHED CLOSELY... THOUGH...AS THE POTENTIAL EXISTS FOR THE COLD AIR TO SETTLE INTO THE STATE BY LATE IN THE WEEKEND AND A LOW TO FORM IN THE NORTHERN GULF SLIDING NORTHEAST WHILE SENDING AMPLE MOISTURE NORTH INTO OUR AREA ON THE COLD SIDE OF THIS ARCTIC BOUNDARY. FOR NOW...HAVE GONE WITH JUST SMALL CHANCES FOR SNOW FROM SATURDAY AFTERNOON THROUGH SUNDAY... BUT THAT WILL SURELY NEED TO BE ADJUSTED ONE WAY OR ANOTHER AS THE MODELS GET A BETTER HANDLE ON THIS SITUATION IN FUTURE RUNS. THE CR GRID LOAD MADE FOR AN OKAY START TO THE EXTENDED FORECAST GRIDS WITH CHANGES MADE PRIMARILY TO BETTER REFLECT THE LATEST ECMWF SOLUTION FOR THE UPCOMING WEEKEND. ALSO...MADE SOME TYPICAL RIDGE AND VALLEY TEMPERATURE ADJUSTMENTS FOR LOWS EACH NIGHT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 632 AM EST MON JAN 26 2015 MOST SITES HAVE COME DOWN THIS MORNING TO IFR AND LIFR CONDITIONS. A FEW SITES ARE SEEING LOWER VIS DUE TO FOG AND/OR SHOWER ACTIVITY MOVING ACROSS THOSE SITES. COLDER AIR IS SLOWING MOVING INTO THE REGION THIS MORNING AND WILL TRANSITION RAIN SHOWERS TO SNOW SHOWERS AS WE GO THROUGH THE MORNING. OTHERWISE A FEW SITES ARE SEEING GUSTY WINDS AROUND 15 TO 20 KTS AS WINDS BEGIN SWITCHING WEST TO NORTHWEST THROUGH THE DAY AS LOW CONTINUES TO EXIT TO THE EAST. OTHERWISE SITES ARE EXPECTED TO IMPROVE LATER THIS AFTERNOON AS DRIER AIR CONTINUES TO FILTER INTO EASTERN KY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DJ SHORT TERM...DJ LONG TERM...GREIF AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
633 AM EST MON JAN 26 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 342 AM EST MON JAN 26 2015 WSR-88D THIS MORNING HAS CONTINUED TO SHOW AREAS OF RAIN SHOWERS MOVING ACROSS EASTERN KY THIS MORNING. BEST COVERAGE HAS GENERALLY BEEN ACROSS THE FAR SOUTHERN PORTIONS OF THE REGION THIS MORNING. HOWEVER THIS MORNING WE HAVE SEEN GENERALLY LOWER AMTS OF PRECIP AND TEMPS ARE STILL ABOVE FREEZING AT MOST LOCATIONS BESIDE BLACK MTN AT 8Z. GIVEN THIS HAVE LESSEN POPS AND ALSO LESSENED QPF AMTS ACROSS THE REGION. THIS MAY STILL BE TOO OPTIMISTIC AS RETURNS FROM RADAR HAVE BEEN QUITE LOW ACROSS CENTRAL AND WESTERN KY THIS MORNING. THIS TREND OF LOWERING REFLECTIVITIES IS ALSO BACK UP BY THE HRRR WHICH ALSO INITIALIZED FAIRLY WELL AT 7Z. OTHERWISE LEFT OVER SHOWERS WILL SLOWLY TRANSITION TO SNOW SHOWERS THROUGH THE DAY WITH BEST COVERAGE ACROSS THE FAR EAST THIS AFTERNOON. THIS SURFACE LOW AND UPPER LEVEL TROUGH WILL CONTINUE EXIT EAST WHERE IT DEVELOPS INTO A STRONG NOREASTER ALONG THE ATLANTIC SEABOARD LATER TODAY. ACROSS EASTERN KY WE WILL CONTINUE TO TRANSITION TO GENERALLY WEST TO NW FLOW. MODELS DO SHOW A FETCH OF MOISTURE DROPPING SOUTH FROM THE GREAT LAKES TONIGHT INTO TUESDAY. RIGHT NOW HAVE MOVED TOWARD SLIGHT CHANCES OF SNOW SHOWERS MAINLY ACROSS SW PORTION OF THE CWA WHERE BETTER PLACEMENT OF MOISTURE AXIS EXISTS. EVEN SO GENERALLY MOSTLY CLOUDY CONDITIONS WILL PREVAIL FOR MUCH OF THE PERIOD AREA WIDE COUPLED WITH GENERALLY BELOW NORMAL TEMPS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 445 AM EST MON JAN 26 2015 THE MODELS ARE IN GOOD AGREEMENT ALOFT FOR THE FIRST PART OF THE EXTENDED AND ARE IN FAIR AGREEMENT WITH THE LATTER PART. THE RUB HERE IS THAT THE CONSISTENCY HAS BEEN TAKING HITS LATELY WITH THE FORECAST FOR NEXT WEEKEND. A ONCE DISCARDED SOLUTION...MAINLY SEEN EARLIER IN THE GFS...HAS RETURNED WITH SOME LIMITED SUPPORT FROM THE ECMWF. EARLY ON...THE FOCUS WILL BE ON A DEEP CYCLONE OFF THE EASTERN SEABOARD WHILE A FAST FLOW OF ENERGY ROILS ABOVE EAST KENTUCKY ON A GENERALLY NORTHWEST TO SOUTHEAST PATH INTO WEDNESDAY MORNING. THIS VORT STREAM IS SHUNTED EAST BY MIDDAY WEDNESDAY AS HIGHER HEIGHTS FROM A WEAKENING SOUTHERN RIDGE MOVES INTO THE MID MISSISSIPPI VALLEY AND THEN OVER THE LOWER OHIO BASIN. AT THE SAME TIME...A DEVELOPING TROUGH WILL DIP INTO THE CENTRAL PLAINS AND SLIDE EAST. THIS FEATURE RAMPS UP INTO THE DAY THURSDAY WITH THE GFS PROVIDING BETTER SUPPORT FOR THE MORE ROBUST SOLUTION OF THE ECMWF. THIS TROUGH CROSSES EAST KENTUCKY LATER THURSDAY NIGHT WITH FLAT FLOW TO FOLLOW. HOWEVER...OVER THE SOUTHWEST PARTS OF THE NATION A LARGE CLOSED LOW IN THE SOUTHERN STREAM IS NOW DEPICTED...PARTICULARLY BY THE LATEST ECMWF...OPENING UP AND SPILLING ITS ENERGY EAST INTO THE FLOW RIDING OVER THE TENNESSEE VALLEY. THE MODELS NOW SHOW SOME CONNECTION TO THE NORTHERN AND SOUTHERN STREAMS WHICH WOULD CERTAINLY MAKE THINGS MORE INTERESTING FOR THE UPCOMING WEEKEND IF THAT PANS OUT. FOR NOW...WILL SHOW ONLY LIMITED INTERACTION AND EASE INTO A MORE DYNAMIC SCENARIO GIVEN THE UNCERTAINTY AND LACK OF MODEL RUN TO RUN CONSISTENCY WITH THIS PART OF THE FORECAST. IN GENERAL...A BLEND OF THE MODELS WAS PREFERRED THROUGH THE BULK OF THE FORECAST WITH SOME ADJUSTMENT TOWARD THE PREVIOUS FORECAST FOR NEXT WEEKEND GIVEN THE CONSISTENCY CONCERNS. SENSIBLE WEATHER WILL FEATURE THE ENDING OF THE UPSLOPE SNOW SHOWERS/FLURRIES IN THE FAR EAST EARLY WEDNESDAY MORNING WITH SOME SUNSHINE RETURNING. THE NEXT CLIPPER SYSTEM WILL THEN MOVE INTO THE OHIO VALLEY ON THURSDAY WITH A CHANCE FOR RAIN AND SNOW ACROSS THE AREA INTO FRIDAY MORNING. ONLY A BRIEF WINDOW FOR DRYING CAN BE EXPECTED FROM FRIDAY NIGHT INTO SATURDAY MORNING BEFORE THE POTENTIAL FOR MAINLY SNOW ARRIVES FROM THE SOUTHWEST IN FAST LOW AND MID LEVEL FLOW RIDING ALONG A WEST TO EAST ARCTIC BOUNDARY LYING OVER THE OHIO VALLEY. THIS BOUNDARY IS EXPECTED TO PUSH ON THROUGH KENTUCKY BY SUNDAY MORNING WITH SNOW CHANCES CONTINUING...MAINLY IN THE SOUTHERN PARTS OF THE CWA. THIS SETUP WILL NEED TO BE WATCHED CLOSELY... THOUGH...AS THE POTENTIAL EXISTS FOR THE COLD AIR TO SETTLE INTO THE STATE BY LATE IN THE WEEKEND AND A LOW TO FORM IN THE NORTHERN GULF SLIDING NORTHEAST WHILE SENDING AMPLE MOISTURE NORTH INTO OUR AREA ON THE COLD SIDE OF THIS ARCTIC BOUNDARY. FOR NOW...HAVE GONE WITH JUST SMALL CHANCES FOR SNOW FROM SATURDAY AFTERNOON THROUGH SUNDAY... BUT THAT WILL SURELY NEED TO BE ADJUSTED ONE WAY OR ANOTHER AS THE MODELS GET A BETTER HANDLE ON THIS SITUATION IN FUTURE RUNS. THE CR GRID LOAD MADE FOR AN OKAY START TO THE EXTENDED FORECAST GRIDS WITH CHANGES MADE PRIMARILY TO BETTER REFLECT THE LATEST ECMWF SOLUTION FOR THE UPCOMING WEEKEND. ALSO...MADE SOME TYPICAL RIDGE AND VALLEY TEMPERATURE ADJUSTMENTS FOR LOWS EACH NIGHT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 632 AM EST MON JAN 26 2015 MOST SITES HAVE COME DOWN THIS MORNING TO IFR AND LIFR CONDITIONS. A FEW SITES ARE SEEING LOWER VIS DUE TO FOG AND/OR SHOWER ACTIVITY MOVING ACROSS THOSE SITES. COLDER AIR IS SLOWING MOVING INTO THE REGION THIS MORNING AND WILL TRANSITION RAIN SHOWERS TO SNOW SHOWERS AS WE GO THROUGH THE MORNING. OTHERWISE A FEW SITES ARE SEEING GUSTY WINDS AROUND 15 TO 20 KTS AS WINDS BEGIN SWITCHING WEST TO NORTHWEST THROUGH THE DAY AS LOW CONTINUES TO EXIT TO THE EAST. OTHERWISE SITES ARE EXPECTED TO IMPROVE LATER THIS AFTERNOON AS DRIER AIR CONTINUES TO FILTER INTO EASTERN KY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJ LONG TERM...GREIF AVIATION...DJ
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
445 AM EST MON JAN 26 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 342 AM EST MON JAN 26 2015 WSR-88D THIS MORNING HAS CONTINUED TO SHOW AREAS OF RAIN SHOWERS MOVING ACROSS EASTERN KY THIS MORNING. BEST COVERAGE HAS GENERALLY BEEN ACROSS THE FAR SOUTHERN PORTIONS OF THE REGION THIS MORNING. HOWEVER THIS MORNING WE HAVE SEEN GENERALLY LOWER AMTS OF PRECIP AND TEMPS ARE STILL ABOVE FREEZING AT MOST LOCATIONS BESIDE BLACK MTN AT 8Z. GIVEN THIS HAVE LESSEN POPS AND ALSO LESSENED QPF AMTS ACROSS THE REGION. THIS MAY STILL BE TOO OPTIMISTIC AS RETURNS FROM RADAR HAVE BEEN QUITE LOW ACROSS CENTRAL AND WESTERN KY THIS MORNING. THIS TREND OF LOWERING REFLECTIVITIES IS ALSO BACK UP BY THE HRRR WHICH ALSO INITIALIZED FAIRLY WELL AT 7Z. OTHERWISE LEFT OVER SHOWERS WILL SLOWLY TRANSITION TO SNOW SHOWERS THROUGH THE DAY WITH BEST COVERAGE ACROSS THE FAR EAST THIS AFTERNOON. THIS SURFACE LOW AND UPPER LEVEL TROUGH WILL CONTINUE EXIT EAST WHERE IT DEVELOPS INTO A STRONG NOREASTER ALONG THE ATLANTIC SEABOARD LATER TODAY. ACROSS EASTERN KY WE WILL CONTINUE TO TRANSITION TO GENERALLY WEST TO NW FLOW. MODELS DO SHOW A FETCH OF MOISTURE DROPPING SOUTH FROM THE GREAT LAKES TONIGHT INTO TUESDAY. RIGHT NOW HAVE MOVED TOWARD SLIGHT CHANCES OF SNOW SHOWERS MAINLY ACROSS SW PORTION OF THE CWA WHERE BETTER PLACEMENT OF MOISTURE AXIS EXISTS. EVEN SO GENERALLY MOSTLY CLOUDY CONDITIONS WILL PREVAIL FOR MUCH OF THE PERIOD AREA WIDE COUPLED WITH GENERALLY BELOW NORMAL TEMPS. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 445 AM EST MON JAN 26 2015 THE MODELS ARE IN GOOD AGREEMENT ALOFT FOR THE FIRST PART OF THE EXTENDED AND ARE IN FAIR AGREEMENT WITH THE LATTER PART. THE RUB HERE IS THAT THE CONSISTENCY HAS BEEN TAKING HITS LATELY WITH THE FORECAST FOR NEXT WEEKEND. A ONCE DISCARDED SOLUTION...MAINLY SEEN EARLIER IN THE GFS...HAS RETURNED WITH SOME LIMITED SUPPORT FROM THE ECMWF. EARLY ON...THE FOCUS WILL BE ON A DEEP CYCLONE OFF THE EASTERN SEABOARD WHILE A FAST FLOW OF ENERGY ROILS ABOVE EAST KENTUCKY ON A GENERALLY NORTHWEST TO SOUTHEAST PATH INTO WEDNESDAY MORNING. THIS VORT STREAM IS SHUNTED EAST BY MIDDAY WEDNESDAY AS HIGHER HEIGHTS FROM A WEAKENING SOUTHERN RIDGE MOVES INTO THE MID MISSISSIPPI VALLEY AND THEN OVER THE LOWER OHIO BASIN. AT THE SAME TIME...A DEVELOPING TROUGH WILL DIP INTO THE CENTRAL PLAINS AND SLIDE EAST. THIS FEATURE RAMPS UP INTO THE DAY THURSDAY WITH THE GFS PROVIDING BETTER SUPPORT FOR THE MORE ROBUST SOLUTION OF THE ECMWF. THIS TROUGH CROSSES EAST KENTUCKY LATER THURSDAY NIGHT WITH FLAT FLOW TO FOLLOW. HOWEVER...OVER THE SOUTHWEST PARTS OF THE NATION A LARGE CLOSED LOW IN THE SOUTHERN STREAM IS NOW DEPICTED...PARTICULARLY BY THE LATEST ECMWF...OPENING UP AND SPILLING ITS ENERGY EAST INTO THE FLOW RIDING OVER THE TENNESSEE VALLEY. THE MODELS NOW SHOW SOME CONNECTION TO THE NORTHERN AND SOUTHERN STREAMS WHICH WOULD CERTAINLY MAKE THINGS MORE INTERESTING FOR THE UPCOMING WEEKEND IF THAT PANS OUT. FOR NOW...WILL SHOW ONLY LIMITED INTERACTION AND EASE INTO A MORE DYNAMIC SCENARIO GIVEN THE UNCERTAINTY AND LACK OF MODEL RUN TO RUN CONSISTENCY WITH THIS PART OF THE FORECAST. IN GENERAL...A BLEND OF THE MODELS WAS PREFERRED THROUGH THE BULK OF THE FORECAST WITH SOME ADJUSTMENT TOWARD THE PREVIOUS FORECAST FOR NEXT WEEKEND GIVEN THE CONSISTENCY CONCERNS. SENSIBLE WEATHER WILL FEATURE THE ENDING OF THE UPSLOPE SNOW SHOWERS/FLURRIES IN THE FAR EAST EARLY WEDNESDAY MORNING WITH SOME SUNSHINE RETURNING. THE NEXT CLIPPER SYSTEM WILL THEN MOVE INTO THE OHIO VALLEY ON THURSDAY WITH A CHANCE FOR RAIN AND SNOW ACROSS THE AREA INTO FRIDAY MORNING. ONLY A BRIEF WINDOW FOR DRYING CAN BE EXPECTED FROM FRIDAY NIGHT INTO SATURDAY MORNING BEFORE THE POTENTIAL FOR MAINLY SNOW ARRIVES FROM THE SOUTHWEST IN FAST LOW AND MID LEVEL FLOW RIDING ALONG A WEST TO EAST ARCTIC BOUNDARY LYING OVER THE OHIO VALLEY. THIS BOUNDARY IS EXPECTED TO PUSH ON THROUGH KENTUCKY BY SUNDAY MORNING WITH SNOW CHANCES CONTINUING...MAINLY IN THE SOUTHERN PARTS OF THE CWA. THIS SETUP WILL NEED TO BE WATCHED CLOSELY... THOUGH...AS THE POTENTIAL EXISTS FOR THE COLD AIR TO SETTLE INTO THE STATE BY LATE IN THE WEEKEND AND A LOW TO FORM IN THE NORTHERN GULF SLIDING NORTHEAST WHILE SENDING AMPLE MOISTURE NORTH INTO OUR AREA ON THE COLD SIDE OF THIS ARCTIC BOUNDARY. FOR NOW...HAVE GONE WITH JUST SMALL CHANCES FOR SNOW FROM SATURDAY AFTERNOON THROUGH SUNDAY... BUT THAT WILL SURELY NEED TO BE ADJUSTED ONE WAY OR ANOTHER AS THE MODELS GET A BETTER HANDLE ON THIS SITUATION IN FUTURE RUNS. THE CR GRID LOAD MADE FOR AN OKAY START TO THE EXTENDED FORECAST GRIDS WITH CHANGES MADE PRIMARILY TO BETTER REFLECT THE LATEST ECMWF SOLUTION FOR THE UPCOMING WEEKEND. ALSO...MADE SOME TYPICAL RIDGE AND VALLEY TEMPERATURE ADJUSTMENTS FOR LOWS EACH NIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1253 AM EST MON JAN 26 2015 TONIGHT WILL BE TRICKY IN TERMS OF CIGS AS SITES HAVE BEEN AROUND OR MVFR CEILINGS THUS FAR TONIGHT. THE QUESTION THEN BECOMES HOW QUICKLY TO WE SEE IFR CONDITIONS OVERNIGHT AND MORNING HOURS. RIGHT NOW HAVE SITES GOING IFR BY 10 TO 11 Z BEFORE SITES IMPROVE TO MVFR THIS AFTERNOON. THE LOW PRESSURE THAT HAS BEEN POISED TO MOVE ACROSS THE REGION IS TRACKING OVER EASTERN KY THIS HOUR AND WILL CONTINUE TO MOVE EAST TONIGHT. THIS WILL CONTINUE TO BRING PERIODS OF RAIN AND EVENTUALLY A CHANGEOVER TO SNOW AS WE MOVE INTO THE EARLY MORNING HOURS. THIS WILL THEN TRANSITION TO MORE SNOW SHOWER ACTIVITY AS WE MOVE INTO THE AFTERNOON. THIS LOW PRESSURE WILL ALSO USHER IN STRONGER NW FLOW LATER TONIGHT INTO TOMORROW WITH GUSTY WINDS AROUND 20 KNOTS POSSIBLE OVERNIGHT INTO THE DAY TODAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJ LONG TERM...GREIF AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
343 AM EST MON JAN 26 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 342 AM EST MON JAN 26 2015 WSR-88D THIS MORNING HAS CONTINUED TO SHOW AREAS OF RAIN SHOWERS MOVING ACROSS EASTERN KY THIS MORNING. BEST COVERAGE HAS GENERALLY BEEN ACROSS THE FAR SOUTHERN PORTIONS OF THE REGION THIS MORNING. HOWEVER THIS MORNING WE HAVE SEEN GENERALLY LOWER AMTS OF PRECIP AND TEMPS ARE STILL ABOVE FREEZING AT MOST LOCATIONS BESIDE BLACK MTN AT 8Z. GIVEN THIS HAVE LESSEN POPS AND ALSO LESSENED QPF AMTS ACROSS THE REGION. THIS MAY STILL BE TOO OPTIMISTIC AS RETURNS FROM RADAR HAVE BEEN QUITE LOW ACROSS CENTRAL AND WESTERN KY THIS MORNING. THIS TREND OF LOWERING REFLECTIVITIES IS ALSO BACK UP BY THE HRRR WHICH ALSO INITIALIZED FAIRLY WELL AT 7Z. OTHERWISE LEFT OVER SHOWERS WILL SLOWLY TRANSITION TO SNOW SHOWERS THROUGH THE DAY WITH BEST COVERAGE ACROSS THE FAR EAST THIS AFTERNOON. THIS SURFACE LOW AND UPPER LEVEL TROUGH WILL CONTINUE EXIT EAST WHERE IT DEVELOPS INTO A STRONG NOREASTER ALONG THE ATLANTIC SEABOARD LATER TODAY. ACROSS EASTERN KY WE WILL CONTINUE TO TRANSITION TO GENERALLY WEST TO NW FLOW. MODELS DO SHOW A FETCH OF MOISTURE DROPPING SOUTH FROM THE GREAT LAKES TONIGHT INTO TUESDAY. RIGHT NOW HAVE MOVED TOWARD SLIGHT CHANCES OF SNOW SHOWERS MAINLY ACROSS SW PORTION OF THE CWA WHERE BETTER PLACEMENT OF MOISTURE AXIS EXISTS. EVEN SO GENERALLY MOSTLY CLOUDY CONDITIONS WILL PREVAIL FOR MUCH OF THE PERIOD AREA WIDE COUPLED WITH GENERALLY BELOW NORMAL TEMPS. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 PM EST SUN JAN 25 2015 A RATHER AMPLIFIED PATTERN IS EXPECTED TO BEGIN THE PERIOD. MODELS REMAIN IN GENERALLY IN GOOD AGREEMENT FOR MOST OF THE PERIOD...WITH DIFFERENCES INCREASING TOWARD THE END OF THE PERIOD. AT THE START OF THE PERIOD A TROUGH IS EXPECTED TO BE IN PLACE FROM THE GREAT LAKES SOUTH INTO THE MID ATLANTIC SATES AND OFF THE SOUTHEASTERN US COAST...WITH A RIDGE OF HIGH PRESSURE FROM MEXICO NORTH INTO THE SOUTHERN PLAINS AND ROCKIES. AT THE SFC THE A DEEP SFC LOW/BLIZZARD WILL BE MOVING ALONG THE NORTHEAST US COAST TO START THE PERIOD WITH A RIDGE OF HIGH PRESSURE AT THE SFC EXTENDING FROM ONTARIO INTO THE GREAT LAKES AND MS VALLEY REGION. A SERIES OF SHORTWAVES IN NW FLOW BETWEEN THE TWO WILL DROP FROM THE GREAT LAKES AND THROUGH THE OH VALLEY AND APPALACHIANS TUESDAY INTO TUESDAY NIGHT. THIS WILL BRING CHANCES FOR SNOW SHOWERS AND REINFORCE A COLD AIRMASS WITH 850 MB TEMPS TO FALL TO THE -8C TO -10C RANGE BY LATE TUE AFTERNOON AND TUE EVENING. AS THE TROUGH AXIS LIFTS TO THE NORTH AND EAST AND THE SFC LOW MOVES FURTHER UP THE EASTERN SEABOARD...HIGH PRESSURE WILL GRADUALLY BUILD INTO THE LOWER OH VALLEY REGION AND APPALACHIANS TUE NIGHT INTO WED. THE INFLUENCE OF THE RIDGING WILL WANE BY LATE WED NIGHT AS A SHORTWAVE MOVING AROUND THE RIDGE OVER THE ROCKIES AND A NORTHERN STREAM TROUGH BEGIN TO JOIN FORCES AND APPROACH THE GREAT LAKES AND MS VALLEY REGION AS WELL AS THE LOWER OH VALLEY REGION. THE ASSOCIATED SFC LOW SHOULD TRACK WELL NORTH OF THE AREA JUST TO THE SOUTH OF THE SOUTHERN GREAT LAKES AND INTO THE MID ATLANTIC STATES FROM WED NIGHT INTO THU NIGHT. THIS SYSTEM WILL HAVE SOMEWHAT LIMITED MOISTURE...AND THIS SHOULD BE ANOTHER EVENT WHERE THE ATMOSPHERE MOISTENS FROM THE TOP DOWN. AT THE ONSET...SOME SNOW COULD MIX IN PENDING THE STRENGTH OF WARM AIR ADVECTION AND MOISTURE ADVECTION LATE WED NIGHT INTO THU MORNING. THE CLOUDS ALSO MAY NOT THICKEN QUICK ENOUGH TO PREVENT AT LEAST A MINOR RIDGE/VALLEY SPLIT FOR THE VALLEYS ON WED EVENING. AT THIS POINT...A LOW IN THE MID TO UPPER 20S OCCURRING AROUND 6Z ON THU IS EXPECTED. COLDER AIR WILL WRAP BACK INTO THE REGION BEHIND THIS SYSTEM AND POSSIBLY CHANGE ANY PRECIP BACK TO SNOW AS IT DEPARTS. HIGH PRESSURE SHOULD THEN BUILD IN TO BRING A DRY START TO THE WEEKEND. THE ECMWF LOWERS HEIGHTS MORE SIGNIFICANTLY ACROSS THE REGION AS WELL AS THE GREAT LAKES AND EASTERN SEABOARD AT THE END OF THE PERIOD AND IS THUS MUCH COLDER WITH THE AIRMASS. ANY SHORTWAVES AT THE END OF THE PERIOD SHOULD BE RATHER MOISTURE STARVED WITH THE MODEL CONSENSUS FAVORING ANYTHING THAT FALLS BEING SNOW. FOR TEMPS LATE IN THE PERIOD...OPTED TO GO A TAD COLDER THAN THE CONSENSUS BLEND...MORE IN LINE WITH ISC CONSENSUS AND GIVING A BIT MORE CREDIT TO THE PAST 2 ECMWF RUNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1253 AM EST MON JAN 26 2015 TONIGHT WILL BE TRICKY IN TERMS OF CIGS AS SITES HAVE BEEN AROUND OR MVFR CEILINGS THUS FAR TONIGHT. THE QUESTION THEN BECOMES HOW QUICKLY TO WE SEE IFR CONDITIONS OVERNIGHT AND MORNING HOURS. RIGHT NOW HAVE SITES GOING IFR BY 10 TO 11 Z BEFORE SITES IMPROVE TO MVFR THIS AFTERNOON. THE LOW PRESSURE THAT HAS BEEN POISED TO MOVE ACROSS THE REGION IS TRACKING OVER EASTERN KY THIS HOUR AND WILL CONTINUE TO MOVE EAST TONIGHT. THIS WILL CONTINUE TO BRING PERIODS OF RAIN AND EVENTUALLY A CHANGEOVER TO SNOW AS WE MOVE INTO THE EARLY MORNING HOURS. THIS WILL THEN TRANSITION TO MORE SNOW SHOWER ACTIVITY AS WE MOVE INTO THE AFTERNOON. THIS LOW PRESSURE WILL ALSO USHER IN STRONGER NW FLOW LATER TONIGHT INTO TOMORROW WITH GUSTY WINDS AROUND 20 KNOTS POSSIBLE OVERNIGHT INTO THE DAY TODAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DJ LONG TERM...JP AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
144 AM EST MON JAN 26 2015 .UPDATE... ISSUED AT 143 AM EST MON JAN 26 2015 DID A QUICK UPDATE TO FRESHEN GRIDS WITH OBS AND TRENDS. RIGHT NOW LOW PRESSURE CONTINUES TO TRACK ACROSS THE REGION THIS EVENING AND MOST OF THIS IS IN THE FORM OF RAIN WITH MOST SITES BESIDES BLACK MT IN THE UPPER 30S TO LOWER 40S THIS HOUR. BEST COVERAGE OF RAIN THIS HOUR IS ACROSS THE SOUTHERN PORTION OF THE CWA WITH MORE SCATTERED ACTIVITY AS YOU MOVE NORTH. TEMPERATURES ARE DROPPING ACROSS FAR WESTERN KY TONIGHT AND THIS IS EXPECTED TO BE THE TREND FROM NW TO SE ACROSS THE STATE OVERNIGHT TONIGHT. WSR-88D RADAR HOWEVER IS NOT SHOWING MUCH IN THE WAY OF RETURNS TO OUR WEST WITH GENERALLY LIGHT BAND OF PRECIP ACROSS WEST AND CENTRAL KY THIS HOUR. THAT SAID COMBINE THIS WITH HRRR THAT SHOWS A GENERAL WEAKENING TREND OF THE PRECIP AS WE MOVE INTO THE MORNING WOULD SUGGEST LIGHTER AMTS AS WE SWITCH TO SNOW IN THE DAWN HOUR. RIGHT NOW WILL ONLY MAKE MINOR CHANGES AND CONTINUE TO MONITOR RADAR AND TRENDS. UPDATE ISSUED AT 1137 PM EST SUN JAN 25 2015 GIVEN THE WELL ABOVE NORMAL TEMPERATURES EXPERIENCED TODAY /SOME LOCATIONS IN THE 50S/...WE JUST REALLY HAVEN/T SEEN A LARGE COOL DOWN ACROSS MUCH OF EASTERN KY THROUGH MOST OF THE EVENING. THIS IS ESPECIALLY TRUE IN AREAS THAT HAVE NOT YET RECEIVED RAIN...OR HAVE ONLY RECEIVED A SMALL AMOUNT. THIS BEING SAID...OTHER THAN ELEVATIONS ABOVE 3000 FT...DON/T EXPECT RAIN TO START CHANGING OVER QUITE AS FAST AS WHAT WAS IN THE PREVIOUS FORECAST. WORKED TO ADJUST THE LOW TEMPERATURE FOR OVERNIGHT...BASED ON THE LATEST MODEL GUIDANCE AND SOUNDINGS...AS WELL AS BASED ON THE ONGOING CONDITIONS WITH TEMPERATURES AND COOLING DOWNSTREAM...PREVIOUS SNOW PACK...ETC. WENT WITH A BLEND OF THE CURRENT FORECAST...THE LATEST HRRR /WHICH SEEMS TO HAVE THE BEST INITIALIZATION FOR THIS SYSTEM/...AND A LITTLE INFLUENCE FROM THE GFS...WHICH TRENDED CLOSER TO OVERALL THINKING FOR THE LOW. THEN...ADJUSTED INDIVIDUAL LOCATIONS TO GET THEM WITHIN BETTER TOLERANCE...INCLUDING BUMPING UP BLACK MOUNTAIN TO 29 DEGREES AND OTHER TERRAIN ABOVE 2500 FEET TO BETWEEN 30 AND 32 DEGREES. FURTHER MORE...GIVEN THE SLOW PROGRESS OF TEMPERATURES FALLING...WENT AHEAD AND PUSHED BACK THE TIMING OF THE LOW TEMPERATURE TO 13Z MONDAY. FROM HERE...USED A MIXTURE OF THE CONS-SHORT AND HAND EDITING TO ADJUST THE DIURNAL CURVE FOR THE REMAINDER OF THE NIGHT. ALL THINGS CONSIDERED...THE SLIGHT UPTICK IN TEMPERATURE FORECAST WILL RESULT IN A SEVERAL HOUR DIFFERENCE IN THE RAIN CHANGING OVER TO SNOW. THIS WILL KEEP ANY SNOW ACCUMULATIONS OUT OF THE FORECAST THROUGH 12Z /WITH THE EXCEPTION OF BLACK MOUNTAIN/...AND LESS SNOW ACCUMULATION IN FOR DURING THE DAY TOMORROW. BLACK MOUNTAIN IS CURRENTLY AT 32 DEGREES...SO THEY MAY START TO MIX WITH SNOW AT ANY TIME. HOWEVER...MOST OF THE REST OF THE AREA WILL LIKELY NOT SEE SNOW MIXING IN UNTIL NEAR DAWN...THEN SLOWLY TRANSITION TO ALL SNOW BETWEEN NOON AND 3PM. BY THIS POINT...MODEL SOUNDINGS ARE SHOWING A STRONG AMOUNT OF DRY AIR CUTTING OFF SOME OF THE BEST ACCUMULATION POTENTIAL DURING THE AFTERNOON. OVERALL...SNOW TOTALS WERE LOWERED ACROSS THE CWA. EXPECT ELEVATIONS ABOVE 3000 FEET TO PICK UP THE HIGHEST AMOUNTS...BETWEEN 1 AND 2 INCHES. SOME OF THE OTHER RIDGES ACROSS THE AREA COULD SEE BETWEEN A HALF AN ONE INCH...BUT A MAJORITY OF THE CWA WILL ONLY PICK UP A HALF INCH OR LESS. MOST OF THIS IS STILL EXPECTED TO FALL BETWEEN 12 AND 18Z WHEN THE BEST LIFT AND MOISTURE AND TEMPERATURES COMBINE...AND SURFACE TEMPERATURES FINALLY FALL ENOUGH TO ALLOW FOR ACCUMULATING SNOW. UPDATE ISSUED AT 706 PM EST SUN JAN 25 2015 FRESHENED UP THE GRIDS WITH THE LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS. THIS RESULTED IN LITTLE OVERALL CHANGE FROM THE ONGOING FORECAST. BASED ON THE CURRENT RADAR RETURNS...AND THE PWAT VALUES OVERNIGHT BEING AROUND A HALF INCH OR LESS...WENT AHEAD AND REDUCED ANY MENTION OF MODERATE RAINFALL/SNOWFALL TO LIGHT. JUST NOT SEEING A WHOLE LOT OF EVIDENCE AT THIS POINT FOR MODERATE TO HEAVY INTENSITIES...THOUGH SNOW COULD HAVE SOME HEAVIER SPOTS AT TIMES TOMORROW MORNING. LATEST NAM12 FORECAST SOUNDINGS REALLY START TO LOSE MOISTURE IN THE UPPER LEVELS BETWEEN 6 AND 9 Z...WITH NOT MUCH LIFT EITHER...ALSO SUPPORTING LIGHTER INTENSITIES. OTHERWISE...FORECAST SEEMS TO BE IN PRETTY GOOD SHAPE OVER THE NEXT FEW HOURS. THE CENTER OF THE LOW IS CURRENTLY OVER SOUTH CENTRAL KY AND MOVING OUR DIRECTION...WITH THE NEXT ROUND OF LIGHT RAIN ABOUT TO SPREAD ACROSS THE CWA OVER THE NEXT 1 TO 2 HOURS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 409 PM EST SUN JAN 25 2015 SURFACE ANALYSIS AS OF 20Z ACROSS THE REGION FEATURES A SMALL LOW PRESSURE SYSTEM OVER THE LOWER MIDWEST TRACKING EAST INTO THE OH VALLEY THIS EVENING. AHEAD OF THIS...SOME SHOWER ACTIVITY HAS BEGUN TO MOVE INTO THE AREA THIS AFTERNOON WITH MORE WIDESPREAD PRECIP BACK WEST INTO WESTERN KENTUCKY AND SOUTHERN INDIANA. PLENTY OF SOUTHWEST FLOW TODAY AND WAA INTO THE AREA HAS ALLOWED FOR TEMPS TO RISE INTO THE UPPER 40S AND EVEN LOWER 50S ACROSS EASTERN KENTUCKY TODAY. MODELS SHOWING THE COLD FRONT TO MOVE THROUGH LATER TONIGHT AFTER 00Z WILL HAVE THE COLDER AIR MOVING IN LATER. THIS ADVECTION WILL BEGIN IN EARNEST JUST AFTER 06Z AS THE FRONT MOVES THROUGH. EXPECTING A CHANGE OVER IN THE HIGHER ELEVATIONS WITH ALREADY TEMPS AT BLACK MOUNTAIN REACHING ITS HIGH FOR THE DAY IN THE UPPER 30S AND IS NOW BEGINNING TO DROP OFF AT THIS HOUR. MODEL PROFILES SHOW A BRIEF PERIOD OF GOOD OMEGA THROUGH THE LAST FEW HOURS OF THE EVENT AS THE FRONT MOVES THROUGH. WITH COLD ENOUGH AIR MOVING IN...THERE COULD BE SOME QUICK BURSTS OF SNOW IN THE HIGHER ELEVATIONS AND EVEN IN THE VALLEYS WHERE COLDER AIR HAS FINALLY MOVED IN. SPEAKING OF TEMPERATURES...LATE TONIGHT AND INTO THE DAY ON MONDAY...TEMPS WILL BE FALLING INTO THE MORNING HOURS BUT SOME SLIGHT RADIATIONAL HEATING DURING THE DAY BEFORE THE CORE OF THE AIR MASS MOVES IN MONDAY AFTERNOON AND INTO MONDAY NIGHT WILL RESULT IN TEMPS RISING A DEGREE OR TWO OR HOLDING STEADY THROUGH THE DAY TOMORROW. TEMPS OVER THE HIGHER TERRAIN SHOULD SLOWLY FALL THROUGH THE DAY. WINDS AFTER FRONTAL PASSAGE MONDAY MORNING WILL THEN SWITCH AROUND TO THE NORTHWEST FOR A FAVORABLE DIRECTION FOR SOME UPSLOPE SNOW SHOWERS THROUGH MONDAY AFTERNOON. MOISTURE DEPTH HANGS AROUND THROUGH MONDAY MORNING AND INTO THE AFTERNOON WITH SOME DECENT LIFT REMAINING ACCORDING TO THE NAM AND GFS SO SOME DECENT SNOW SHOWERS WILL HANG AROUND THROUGH THE DAY ON MONDAY BEFORE TAPERING OFF TO FLURRIES FROM WEST TO EAST INTO MONDAY NIGHT. THE CORE OF THE AIR MASS MOVING IN WILL CAUSE TEMPS TO PLUMMET INTO THE MID 20S MONDAY NIGHT AND WILL LIKELY ADD TO THE THREAT OF HAZARDOUS AND SLICK ROADS. THEREFORE...HAVE ISSUED AN SPS TO HIGHLIGHT THIS THREAT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 PM EST SUN JAN 25 2015 A RATHER AMPLIFIED PATTERN IS EXPECTED TO BEGIN THE PERIOD. MODELS REMAIN IN GENERALLY IN GOOD AGREEMENT FOR MOST OF THE PERIOD...WITH DIFFERENCES INCREASING TOWARD THE END OF THE PERIOD. AT THE START OF THE PERIOD A TROUGH IS EXPECTED TO BE IN PLACE FROM THE GREAT LAKES SOUTH INTO THE MID ATLANTIC SATES AND OFF THE SOUTHEASTERN US COAST...WITH A RIDGE OF HIGH PRESSURE FROM MEXICO NORTH INTO THE SOUTHERN PLAINS AND ROCKIES. AT THE SFC THE A DEEP SFC LOW/BLIZZARD WILL BE MOVING ALONG THE NORTHEAST US COAST TO START THE PERIOD WITH A RIDGE OF HIGH PRESSURE AT THE SFC EXTENDING FROM ONTARIO INTO THE GREAT LAKES AND MS VALLEY REGION. A SERIES OF SHORTWAVES IN NW FLOW BETWEEN THE TWO WILL DROP FROM THE GREAT LAKES AND THROUGH THE OH VALLEY AND APPALACHIANS TUESDAY INTO TUESDAY NIGHT. THIS WILL BRING CHANCES FOR SNOW SHOWERS AND REINFORCE A COLD AIRMASS WITH 850 MB TEMPS TO FALL TO THE -8C TO -10C RANGE BY LATE TUE AFTERNOON AND TUE EVENING. AS THE TROUGH AXIS LIFTS TO THE NORTH AND EAST AND THE SFC LOW MOVES FURTHER UP THE EASTERN SEABOARD...HIGH PRESSURE WILL GRADUALLY BUILD INTO THE LOWER OH VALLEY REGION AND APPALACHIANS TUE NIGHT INTO WED. THE INFLUENCE OF THE RIDGING WILL WANE BY LATE WED NIGHT AS A SHORTWAVE MOVING AROUND THE RIDGE OVER THE ROCKIES AND A NORTHERN STREAM TROUGH BEGIN TO JOIN FORCES AND APPROACH THE GREAT LAKES AND MS VALLEY REGION AS WELL AS THE LOWER OH VALLEY REGION. THE ASSOCIATED SFC LOW SHOULD TRACK WELL NORTH OF THE AREA JUST TO THE SOUTH OF THE SOUTHERN GREAT LAKES AND INTO THE MID ATLANTIC STATES FROM WED NIGHT INTO THU NIGHT. THIS SYSTEM WILL HAVE SOMEWHAT LIMITED MOISTURE...AND THIS SHOULD BE ANOTHER EVENT WHERE THE ATMOSPHERE MOISTENS FROM THE TOP DOWN. AT THE ONSET...SOME SNOW COULD MIX IN PENDING THE STRENGTH OF WARM AIR ADVECTION AND MOISTURE ADVECTION LATE WED NIGHT INTO THU MORNING. THE CLOUDS ALSO MAY NOT THICKEN QUICK ENOUGH TO PREVENT AT LEAST A MINOR RIDGE/VALLEY SPLIT FOR THE VALLEYS ON WED EVENING. AT THIS POINT...A LOW IN THE MID TO UPPER 20S OCCURRING AROUND 6Z ON THU IS EXPECTED. COLDER AIR WILL WRAP BACK INTO THE REGION BEHIND THIS SYSTEM AND POSSIBLY CHANGE ANY PRECIP BACK TO SNOW AS IT DEPARTS. HIGH PRESSURE SHOULD THEN BUILD IN TO BRING A DRY START TO THE WEEKEND. THE ECMWF LOWERS HEIGHTS MORE SIGNIFICANTLY ACROSS THE REGION AS WELL AS THE GREAT LAKES AND EASTERN SEABOARD AT THE END OF THE PERIOD AND IS THUS MUCH COLDER WITH THE AIRMASS. ANY SHORTWAVES AT THE END OF THE PERIOD SHOULD BE RATHER MOISTURE STARVED WITH THE MODEL CONSENSUS FAVORING ANYTHING THAT FALLS BEING SNOW. FOR TEMPS LATE IN THE PERIOD...OPTED TO GO A TAD COLDER THAN THE CONSENSUS BLEND...MORE IN LINE WITH ISC CONSENSUS AND GIVING A BIT MORE CREDIT TO THE PAST 2 ECMWF RUNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1253 AM EST MON JAN 26 2015 TONIGHT WILL BE TRICKY IN TERMS OF CIGS AS SITES HAVE BEEN AROUND OR MVFR CEILINGS THUS FAR TONIGHT. THE QUESTION THEN BECOMES HOW QUICKLY TO WE SEE IFR CONDITIONS OVERNIGHT AND MORNING HOURS. RIGHT NOW HAVE SITES GOING IFR BY 10 TO 11 Z BEFORE SITES IMPROVE TO MVFR THIS AFTERNOON. THE LOW PRESSURE THAT HAS BEEN POISED TO MOVE ACROSS THE REGION IS TRACKING OVER EASTERN KY THIS HOUR AND WILL CONTINUE TO MOVE EAST TONIGHT. THIS WILL CONTINUE TO BRING PERIODS OF RAIN AND EVENTUALLY A CHANGEOVER TO SNOW AS WE MOVE INTO THE EARLY MORNING HOURS. THIS WILL THEN TRANSITION TO MORE SNOW SHOWER ACTIVITY AS WE MOVE INTO THE AFTERNOON. THIS LOW PRESSURE WILL ALSO USHER IN STRONGER NW FLOW LATER TONIGHT INTO TOMORROW WITH GUSTY WINDS AROUND 20 KNOTS POSSIBLE OVERNIGHT INTO THE DAY TODAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DJ SHORT TERM...SHALLENBERGER LONG TERM...JP AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
1254 AM EST MON JAN 26 2015 .UPDATE... ISSUED AT 1137 PM EST SUN JAN 25 2015 GIVEN THE WELL ABOVE NORMAL TEMPERATURES EXPERIENCED TODAY /SOME LOCATIONS IN THE 50S/...WE JUST REALLY HAVEN/T SEEN A LARGE COOL DOWN ACROSS MUCH OF EASTERN KY THROUGH MOST OF THE EVENING. THIS IS ESPECIALLY TRUE IN AREAS THAT HAVE NOT YET RECEIVED RAIN...OR HAVE ONLY RECEIVED A SMALL AMOUNT. THIS BEING SAID...OTHER THAN ELEVATIONS ABOVE 3000 FT...DON/T EXPECT RAIN TO START CHANGING OVER QUITE AS FAST AS WHAT WAS IN THE PREVIOUS FORECAST. WORKED TO ADJUST THE LOW TEMPERATURE FOR OVERNIGHT...BASED ON THE LATEST MODEL GUIDANCE AND SOUNDINGS...AS WELL AS BASED ON THE ONGOING CONDITIONS WITH TEMPERATURES AND COOLING DOWNSTREAM...PREVIOUS SNOW PACK...ETC. WENT WITH A BLEND OF THE CURRENT FORECAST...THE LATEST HRRR /WHICH SEEMS TO HAVE THE BEST INITIALIZATION FOR THIS SYSTEM/...AND A LITTLE INFLUENCE FROM THE GFS...WHICH TRENDED CLOSER TO OVERALL THINKING FOR THE LOW. THEN...ADJUSTED INDIVIDUAL LOCATIONS TO GET THEM WITHIN BETTER TOLERANCE...INCLUDING BUMPING UP BLACK MOUNTAIN TO 29 DEGREES AND OTHER TERRAIN ABOVE 2500 FEET TO BETWEEN 30 AND 32 DEGREES. FURTHER MORE...GIVEN THE SLOW PROGRESS OF TEMPERATURES FALLING...WENT AHEAD AND PUSHED BACK THE TIMING OF THE LOW TEMPERATURE TO 13Z MONDAY. FROM HERE...USED A MIXTURE OF THE CONS-SHORT AND HAND EDITING TO ADJUST THE DIURNAL CURVE FOR THE REMAINDER OF THE NIGHT. ALL THINGS CONSIDERED...THE SLIGHT UPTICK IN TEMPERATURE FORECAST WILL RESULT IN A SEVERAL HOUR DIFFERENCE IN THE RAIN CHANGING OVER TO SNOW. THIS WILL KEEP ANY SNOW ACCUMULATIONS OUT OF THE FORECAST THROUGH 12Z /WITH THE EXCEPTION OF BLACK MOUNTAIN/...AND LESS SNOW ACCUMULATION IN FOR DURING THE DAY TOMORROW. BLACK MOUNTAIN IS CURRENTLY AT 32 DEGREES...SO THEY MAY START TO MIX WITH SNOW AT ANY TIME. HOWEVER...MOST OF THE REST OF THE AREA WILL LIKELY NOT SEE SNOW MIXING IN UNTIL NEAR DAWN...THEN SLOWLY TRANSITION TO ALL SNOW BETWEEN NOON AND 3PM. BY THIS POINT...MODEL SOUNDINGS ARE SHOWING A STRONG AMOUNT OF DRY AIR CUTTING OFF SOME OF THE BEST ACCUMULATION POTENTIAL DURING THE AFTERNOON. OVERALL...SNOW TOTALS WERE LOWERED ACROSS THE CWA. EXPECT ELEVATIONS ABOVE 3000 FEET TO PICK UP THE HIGHEST AMOUNTS...BETWEEN 1 AND 2 INCHES. SOME OF THE OTHER RIDGES ACROSS THE AREA COULD SEE BETWEEN A HALF AN ONE INCH...BUT A MAJORITY OF THE CWA WILL ONLY PICK UP A HALF INCH OR LESS. MOST OF THIS IS STILL EXPECTED TO FALL BETWEEN 12 AND 18Z WHEN THE BEST LIFT AND MOISTURE AND TEMPERATURES COMBINE...AND SURFACE TEMPERATURES FINALLY FALL ENOUGH TO ALLOW FOR ACCUMULATING SNOW. UPDATE ISSUED AT 706 PM EST SUN JAN 25 2015 FRESHENED UP THE GRIDS WITH THE LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS. THIS RESULTED IN LITTLE OVERALL CHANGE FROM THE ONGOING FORECAST. BASED ON THE CURRENT RADAR RETURNS...AND THE PWAT VALUES OVERNIGHT BEING AROUND A HALF INCH OR LESS...WENT AHEAD AND REDUCED ANY MENTION OF MODERATE RAINFALL/SNOWFALL TO LIGHT. JUST NOT SEEING A WHOLE LOT OF EVIDENCE AT THIS POINT FOR MODERATE TO HEAVY INTENSITIES...THOUGH SNOW COULD HAVE SOME HEAVIER SPOTS AT TIMES TOMORROW MORNING. LATEST NAM12 FORECAST SOUNDINGS REALLY START TO LOSE MOISTURE IN THE UPPER LEVELS BETWEEN 6 AND 9 Z...WITH NOT MUCH LIFT EITHER...ALSO SUPPORTING LIGHTER INTENSITIES. OTHERWISE...FORECAST SEEMS TO BE IN PRETTY GOOD SHAPE OVER THE NEXT FEW HOURS. THE CENTER OF THE LOW IS CURRENTLY OVER SOUTH CENTRAL KY AND MOVING OUR DIRECTION...WITH THE NEXT ROUND OF LIGHT RAIN ABOUT TO SPREAD ACROSS THE CWA OVER THE NEXT 1 TO 2 HOURS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 409 PM EST SUN JAN 25 2015 SURFACE ANALYSIS AS OF 20Z ACROSS THE REGION FEATURES A SMALL LOW PRESSURE SYSTEM OVER THE LOWER MIDWEST TRACKING EAST INTO THE OH VALLEY THIS EVENING. AHEAD OF THIS...SOME SHOWER ACTIVITY HAS BEGUN TO MOVE INTO THE AREA THIS AFTERNOON WITH MORE WIDESPREAD PRECIP BACK WEST INTO WESTERN KENTUCKY AND SOUTHERN INDIANA. PLENTY OF SOUTHWEST FLOW TODAY AND WAA INTO THE AREA HAS ALLOWED FOR TEMPS TO RISE INTO THE UPPER 40S AND EVEN LOWER 50S ACROSS EASTERN KENTUCKY TODAY. MODELS SHOWING THE COLD FRONT TO MOVE THROUGH LATER TONIGHT AFTER 00Z WILL HAVE THE COLDER AIR MOVING IN LATER. THIS ADVECTION WILL BEGIN IN EARNEST JUST AFTER 06Z AS THE FRONT MOVES THROUGH. EXPECTING A CHANGE OVER IN THE HIGHER ELEVATIONS WITH ALREADY TEMPS AT BLACK MOUNTAIN REACHING ITS HIGH FOR THE DAY IN THE UPPER 30S AND IS NOW BEGINNING TO DROP OFF AT THIS HOUR. MODEL PROFILES SHOW A BRIEF PERIOD OF GOOD OMEGA THROUGH THE LAST FEW HOURS OF THE EVENT AS THE FRONT MOVES THROUGH. WITH COLD ENOUGH AIR MOVING IN...THERE COULD BE SOME QUICK BURSTS OF SNOW IN THE HIGHER ELEVATIONS AND EVEN IN THE VALLEYS WHERE COLDER AIR HAS FINALLY MOVED IN. SPEAKING OF TEMPERATURES...LATE TONIGHT AND INTO THE DAY ON MONDAY...TEMPS WILL BE FALLING INTO THE MORNING HOURS BUT SOME SLIGHT RADIATIONAL HEATING DURING THE DAY BEFORE THE CORE OF THE AIR MASS MOVES IN MONDAY AFTERNOON AND INTO MONDAY NIGHT WILL RESULT IN TEMPS RISING A DEGREE OR TWO OR HOLDING STEADY THROUGH THE DAY TOMORROW. TEMPS OVER THE HIGHER TERRAIN SHOULD SLOWLY FALL THROUGH THE DAY. WINDS AFTER FRONTAL PASSAGE MONDAY MORNING WILL THEN SWITCH AROUND TO THE NORTHWEST FOR A FAVORABLE DIRECTION FOR SOME UPSLOPE SNOW SHOWERS THROUGH MONDAY AFTERNOON. MOISTURE DEPTH HANGS AROUND THROUGH MONDAY MORNING AND INTO THE AFTERNOON WITH SOME DECENT LIFT REMAINING ACCORDING TO THE NAM AND GFS SO SOME DECENT SNOW SHOWERS WILL HANG AROUND THROUGH THE DAY ON MONDAY BEFORE TAPERING OFF TO FLURRIES FROM WEST TO EAST INTO MONDAY NIGHT. THE CORE OF THE AIR MASS MOVING IN WILL CAUSE TEMPS TO PLUMMET INTO THE MID 20S MONDAY NIGHT AND WILL LIKELY ADD TO THE THREAT OF HAZARDOUS AND SLICK ROADS. THEREFORE...HAVE ISSUED AN SPS TO HIGHLIGHT THIS THREAT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 PM EST SUN JAN 25 2015 A RATHER AMPLIFIED PATTERN IS EXPECTED TO BEGIN THE PERIOD. MODELS REMAIN IN GENERALLY IN GOOD AGREEMENT FOR MOST OF THE PERIOD...WITH DIFFERENCES INCREASING TOWARD THE END OF THE PERIOD. AT THE START OF THE PERIOD A TROUGH IS EXPECTED TO BE IN PLACE FROM THE GREAT LAKES SOUTH INTO THE MID ATLANTIC SATES AND OFF THE SOUTHEASTERN US COAST...WITH A RIDGE OF HIGH PRESSURE FROM MEXICO NORTH INTO THE SOUTHERN PLAINS AND ROCKIES. AT THE SFC THE A DEEP SFC LOW/BLIZZARD WILL BE MOVING ALONG THE NORTHEAST US COAST TO START THE PERIOD WITH A RIDGE OF HIGH PRESSURE AT THE SFC EXTENDING FROM ONTARIO INTO THE GREAT LAKES AND MS VALLEY REGION. A SERIES OF SHORTWAVES IN NW FLOW BETWEEN THE TWO WILL DROP FROM THE GREAT LAKES AND THROUGH THE OH VALLEY AND APPALACHIANS TUESDAY INTO TUESDAY NIGHT. THIS WILL BRING CHANCES FOR SNOW SHOWERS AND REINFORCE A COLD AIRMASS WITH 850 MB TEMPS TO FALL TO THE -8C TO -10C RANGE BY LATE TUE AFTERNOON AND TUE EVENING. AS THE TROUGH AXIS LIFTS TO THE NORTH AND EAST AND THE SFC LOW MOVES FURTHER UP THE EASTERN SEABOARD...HIGH PRESSURE WILL GRADUALLY BUILD INTO THE LOWER OH VALLEY REGION AND APPALACHIANS TUE NIGHT INTO WED. THE INFLUENCE OF THE RIDGING WILL WANE BY LATE WED NIGHT AS A SHORTWAVE MOVING AROUND THE RIDGE OVER THE ROCKIES AND A NORTHERN STREAM TROUGH BEGIN TO JOIN FORCES AND APPROACH THE GREAT LAKES AND MS VALLEY REGION AS WELL AS THE LOWER OH VALLEY REGION. THE ASSOCIATED SFC LOW SHOULD TRACK WELL NORTH OF THE AREA JUST TO THE SOUTH OF THE SOUTHERN GREAT LAKES AND INTO THE MID ATLANTIC STATES FROM WED NIGHT INTO THU NIGHT. THIS SYSTEM WILL HAVE SOMEWHAT LIMITED MOISTURE...AND THIS SHOULD BE ANOTHER EVENT WHERE THE ATMOSPHERE MOISTENS FROM THE TOP DOWN. AT THE ONSET...SOME SNOW COULD MIX IN PENDING THE STRENGTH OF WARM AIR ADVECTION AND MOISTURE ADVECTION LATE WED NIGHT INTO THU MORNING. THE CLOUDS ALSO MAY NOT THICKEN QUICK ENOUGH TO PREVENT AT LEAST A MINOR RIDGE/VALLEY SPLIT FOR THE VALLEYS ON WED EVENING. AT THIS POINT...A LOW IN THE MID TO UPPER 20S OCCURRING AROUND 6Z ON THU IS EXPECTED. COLDER AIR WILL WRAP BACK INTO THE REGION BEHIND THIS SYSTEM AND POSSIBLY CHANGE ANY PRECIP BACK TO SNOW AS IT DEPARTS. HIGH PRESSURE SHOULD THEN BUILD IN TO BRING A DRY START TO THE WEEKEND. THE ECMWF LOWERS HEIGHTS MORE SIGNIFICANTLY ACROSS THE REGION AS WELL AS THE GREAT LAKES AND EASTERN SEABOARD AT THE END OF THE PERIOD AND IS THUS MUCH COLDER WITH THE AIRMASS. ANY SHORTWAVES AT THE END OF THE PERIOD SHOULD BE RATHER MOISTURE STARVED WITH THE MODEL CONSENSUS FAVORING ANYTHING THAT FALLS BEING SNOW. FOR TEMPS LATE IN THE PERIOD...OPTED TO GO A TAD COLDER THAN THE CONSENSUS BLEND...MORE IN LINE WITH ISC CONSENSUS AND GIVING A BIT MORE CREDIT TO THE PAST 2 ECMWF RUNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1253 AM EST MON JAN 26 2015 TONIGHT WILL BE TRICKY IN TERMS OF CIGS AS SITES HAVE BEEN AROUND OR MVFR CEILINGS THUS FAR TONIGHT. THE QUESTION THEN BECOMES HOW QUICKLY TO WE SEE IFR CONDITIONS OVERNIGHT AND MORNING HOURS. RIGHT NOW HAVE SITES GOING IFR BY 10 TO 11 Z BEFORE SITES IMPROVE TO MVFR THIS AFTERNOON. THE LOW PRESSURE THAT HAS BEEN POISED TO MOVE ACROSS THE REGION IS TRACKING OVER EASTERN KY THIS HOUR AND WILL CONTINUE TO MOVE EAST TONIGHT. THIS WILL CONTINUE TO BRING PERIODS OF RAIN AND EVENTUALLY A CHANGEOVER TO SNOW AS WE MOVE INTO THE EARLY MORNING HOURS. THIS WILL THEN TRANSITION TO MORE SNOW SHOWER ACTIVITY AS WE MOVE INTO THE AFTERNOON. THIS LOW PRESSURE WILL ALSO USHER IN STRONGER NW FLOW LATER TONIGHT INTO TOMORROW WITH GUSTY WINDS AROUND 20 KNOTS POSSIBLE OVERNIGHT INTO THE DAY TODAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...SHALLENBERGER LONG TERM...JP AVIATION...DJ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1216 AM EST Mon Jan 26 2015 ...Updated Aviation Discussion... ...Forecast Update... Issued at 855 PM EST Sun Jan 25 2015 The surface low pressure center now is east of Louisville, with the airport going over to northerly winds. Those winds will pick up from the northwest the rest of the night as the gradient tightens up. Precipitation across our region still is all rain, though just north of us in IND`s area, seeing some snow reports from a few of the bordering AWOS`s. HRRR still gives a brief shot at a deformation band taking a swipe at our counties northeast of Louisville over the next few hours, but otherwise the precip looks to be rather light, save for the moderate rain showers along the KY/TN border right now. Precipitation totals for the day so far are in the 1-2 tenths of an inch range. This bodes a little better against their being lots of black ice in the morning, as winds behind the low pressure will act to dry out the roadways some. However we still have the chance for freezing drizzle, according to forecast soundings, and this could create a glaze on its own. Will keep the SPS going and let the mid shift decide, as road reports are coming in, if an upgrade to a Traveler`s Advisory is needed before the morning rush hour Monday. Did another grid update, but forecast still looks on track, so no need for a zone update. Issued at 625 PM EST Sun Jan 25 2015 Looked through the forecast grids and tweaked toward current conditions. After leaning towards the high-res consensus models for the various parameters, ended up coming up with similar numbers for QPF and snow totals as ongoing forecast. Still more concerned about the threat for wet roads freezing than snow accumulations, especially in the area already highlighted by the previous forecaster. The possible saving grace here will be gusty northwest winds that may help to dry off some of the roads before they get a chance to freeze. Will be issuing updates through the evening and overnight, so stay tuned. .SHORT TERM (Now through Monday Night)... Issued at 310 PM EST Sun Jan 25 2015 ...Light wintry precipitation could cause slick spots overnight into Monday morning... The surface low associated with a strong PV anomaly is now working across southern Illinois, and will continue to slide ESE across our area this evening. Light to occasionally moderate rainfall will continue late this afternoon and evening ahead of this feature. Most spots should see around a quarter of an inch of rainfall, with locaized spots up to a half an inch. As the system departs to our east tonight, a sharp cold front will slide NW to SE across our area with rapidly dropping temperatures into the mid 20s. Enough low level moisture looks to linger during this time to support a change over to light snow. Can`t rule out some freezing drizzle as well as saturation only goes up to around -7 or -8 C, bringing the availability of ice crystals into question. Either way, the combination of wet roads (from recent heavier rainfall), and potential for a light snow dusting, or a very thin glaze of ice could lead to some travel problems ahead of and into the morning commute. Confidence isn`t overly high in widespread travel problems, but enough that special mention should be given. Issued a Special Weather Statement to highlight concerns. If confidence does become higher, then can`t rule out an upgraded product with future updates. Overall, kept light snow as the predominant p-type as we head toward dawn, with generally a half an inch or less of snow accumulation. Most likely area to see more problems with slick roads should be east of I-65 and along and north of I-64. Expect lingering light snow/flurries/or freezing drizzle along and east of I-75 through the first part of Monday. Temperatures will struggle for much of the day under steady cold advection and only expect highs in the low and mid 30s. Skies should stay mostly cloudy to cloudy under lingering low clouds. As we move into Monday evening/Monday night, we`ll watch as the left exit region of an upper jet dives sharply south southeastward overnight. As it does so, 1000-700 mb moisture will pool underneath and should result in some light precipitation across the area, mostly in the form of light snow. Best location for this looks to be along and west of I-65 Monday evening, moving to along and east of I-65 late Monday night. .LONG TERM (Tuesday through Sunday)... Issued at 250 PM EST Sun Jan 25 2015 Several light precipitation chances still remain the long term period as we remain in an unsettled weather pattern. Tues small vort waves on the back side of a broad upper trough will create snow shower chances during the morning hours and then possibly changing over to a rain/snow mix west of I-65/remaining snow east of I-65 during the afternoon hours. A light snow accumulation may result from this snow shower activity on Tuesday. Flurries will likely last into the evening hours. The next precip chances will come Wed night into Thurs as a clipper system moves east across the upper Midwest. At this time, the low associated with this clipper looks to pass to our north and actually pull up a decent amount of warm air on Wed night. Precip may start as a brief wintry mix Wed night and then transition to plain rain as upper 30s and lower 40s temps get pulled into our area. Southerly winds and a noticeably warmer airmass will result in rain on Thurs with high temps reaching the upper 40s to around 50. Precipitation will likely end Thurs night as light snow or a rain/snow mix. Temps will run slightly below normal Tues/Wed, then a warm day expected for Thurs, and back to slightly below normal for the end of the week. The weekend forecast is much less certain with models backing off of any major weather systems to bring us notable precip. Have scaled back POPs to 20% for Sat night/Sun night with snow or rain/snow being the p-type. && .AVIATION (06Z TAF Update)... Issued at 1215 AM EST Mon Jan 26 2015 Low-end MVFR and IFR conditions continue early this morning, but there should be a slow improvement through the TAF period. A cold front has just pushed through KSDF, and will slide through KBWG and KLEX in the next couple of hours. This front will bring gusty northwesterly winds, likely pushing 20-25 knots at times. In addition, the passage of this front may bring a brief period of snow, but it does not appear as if it will amount to much more than a dusting. Clouds have been bouncing around high-end IFR and fuel-alternate MVFR, but should slowly improve to fuel-alternate MVFR later this morning at all sites, as drier low-level air works in behind the front. This MVFR deck will slowly lift through the day today, with northwesterly winds decreasing through the afternoon as the low pressure system pushes to the east. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ Update.........RJS Short Term.....BJS Long Term......AMS Aviation.......KJD
AREA FORECAST DISCUSSION
NWS JACKSON KY
1141 PM EST SUN JAN 25 2015 .UPDATE... ISSUED AT 1137 PM EST SUN JAN 25 2015 GIVEN THE WELL ABOVE NORMAL TEMPERATURES EXPERIENCED TODAY /SOME LOCATIONS IN THE 50S/...WE JUST REALLY HAVEN/T SEEN A LARGE COOL DOWN ACROSS MUCH OF EASTERN KY THROUGH MOST OF THE EVENING. THIS IS ESPECIALLY TRUE IN AREAS THAT HAVE NOT YET RECEIVED RAIN...OR HAVE ONLY RECEIVED A SMALL AMOUNT. THIS BEING SAID...OTHER THAN ELEVATIONS ABOVE 3000 FT...DON/T EXPECT RAIN TO START CHANGING OVER QUITE AS FAST AS WHAT WAS IN THE PREVIOUS FORECAST. WORKED TO ADJUST THE LOW TEMPERATURE FOR OVERNIGHT...BASED ON THE LATEST MODEL GUIDANCE AND SOUNDINGS...AS WELL AS BASED ON THE ONGOING CONDITIONS WITH TEMPERATURES AND COOLING DOWNSTREAM...PREVIOUS SNOW PACK...ETC. WENT WITH A BLEND OF THE CURRENT FORECAST...THE LATEST HRRR /WHICH SEEMS TO HAVE THE BEST INITIALIZATION FOR THIS SYSTEM/...AND A LITTLE INFLUENCE FROM THE GFS...WHICH TRENDED CLOSER TO OVERALL THINKING FOR THE LOW. THEN...ADJUSTED INDIVIDUAL LOCATIONS TO GET THEM WITHIN BETTER TOLERANCE...INCLUDING BUMPING UP BLACK MOUNTAIN TO 29 DEGREES AND OTHER TERRAIN ABOVE 2500 FEET TO BETWEEN 30 AND 32 DEGREES. FURTHER MORE...GIVEN THE SLOW PROGRESS OF TEMPERATURES FALLING...WENT AHEAD AND PUSHED BACK THE TIMING OF THE LOW TEMPERATURE TO 13Z MONDAY. FROM HERE...USED A MIXTURE OF THE CONS-SHORT AND HAND EDITING TO ADJUST THE DIURNAL CURVE FOR THE REMAINDER OF THE NIGHT. ALL THINGS CONSIDERED...THE SLIGHT UPTICK IN TEMPERATURE FORECAST WILL RESULT IN A SEVERAL HOUR DIFFERENCE IN THE RAIN CHANGING OVER TO SNOW. THIS WILL KEEP ANY SNOW ACCUMULATIONS OUT OF THE FORECAST THROUGH 12Z /WITH THE EXCEPTION OF BLACK MOUNTAIN/...AND LESS SNOW ACCUMULATION IN FOR DURING THE DAY TOMORROW. BLACK MOUNTAIN IS CURRENTLY AT 32 DEGREES...SO THEY MAY START TO MIX WITH SNOW AT ANY TIME. HOWEVER...MOST OF THE REST OF THE AREA WILL LIKELY NOT SEE SNOW MIXING IN UNTIL NEAR DAWN...THEN SLOWLY TRANSITION TO ALL SNOW BETWEEN NOON AND 3PM. BY THIS POINT...MODEL SOUNDINGS ARE SHOWING A STRONG AMOUNT OF DRY AIR CUTTING OFF SOME OF THE BEST ACCUMULATION POTENTIAL DURING THE AFTERNOON. OVERALL...SNOW TOTALS WERE LOWERED ACROSS THE CWA. EXPECT ELEVATIONS ABOVE 3000 FEET TO PICK UP THE HIGHEST AMOUNTS...BETWEEN 1 AND 2 INCHES. SOME OF THE OTHER RIDGES ACROSS THE AREA COULD SEE BETWEEN A HALF AN ONE INCH...BUT A MAJORITY OF THE CWA WILL ONLY PICK UP A HALF INCH OR LESS. MOST OF THIS IS STILL EXPECTED TO FALL BETWEEN 12 AND 18Z WHEN THE BEST LIFT AND MOISTURE AND TEMPERATURES COMBINE...AND SURFACE TEMPERATURES FINALLY FALL ENOUGH TO ALLOW FOR ACCUMULATING SNOW. UPDATE ISSUED AT 706 PM EST SUN JAN 25 2015 FRESHENED UP THE GRIDS WITH THE LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS. THIS RESULTED IN LITTLE OVERALL CHANGE FROM THE ONGOING FORECAST. BASED ON THE CURRENT RADAR RETURNS...AND THE PWAT VALUES OVERNIGHT BEING AROUND A HALF INCH OR LESS...WENT AHEAD AND REDUCED ANY MENTION OF MODERATE RAINFALL/SNOWFALL TO LIGHT. JUST NOT SEEING A WHOLE LOT OF EVIDENCE AT THIS POINT FOR MODERATE TO HEAVY INTENSITIES...THOUGH SNOW COULD HAVE SOME HEAVIER SPOTS AT TIMES TOMORROW MORNING. LATEST NAM12 FORECAST SOUNDINGS REALLY START TO LOSE MOISTURE IN THE UPPER LEVELS BETWEEN 6 AND 9 Z...WITH NOT MUCH LIFT EITHER...ALSO SUPPORTING LIGHTER INTENSITIES. OTHERWISE...FORECAST SEEMS TO BE IN PRETTY GOOD SHAPE OVER THE NEXT FEW HOURS. THE CENTER OF THE LOW IS CURRENTLY OVER SOUTH CENTRAL KY AND MOVING OUR DIRECTION...WITH THE NEXT ROUND OF LIGHT RAIN ABOUT TO SPREAD ACROSS THE CWA OVER THE NEXT 1 TO 2 HOURS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 409 PM EST SUN JAN 25 2015 SURFACE ANALYSIS AS OF 20Z ACROSS THE REGION FEATURES A SMALL LOW PRESSURE SYSTEM OVER THE LOWER MIDWEST TRACKING EAST INTO THE OH VALLEY THIS EVENING. AHEAD OF THIS...SOME SHOWER ACTIVITY HAS BEGUN TO MOVE INTO THE AREA THIS AFTERNOON WITH MORE WIDESPREAD PRECIP BACK WEST INTO WESTERN KENTUCKY AND SOUTHERN INDIANA. PLENTY OF SOUTHWEST FLOW TODAY AND WAA INTO THE AREA HAS ALLOWED FOR TEMPS TO RISE INTO THE UPPER 40S AND EVEN LOWER 50S ACROSS EASTERN KENTUCKY TODAY. MODELS SHOWING THE COLD FRONT TO MOVE THROUGH LATER TONIGHT AFTER 00Z WILL HAVE THE COLDER AIR MOVING IN LATER. THIS ADVECTION WILL BEGIN IN EARNEST JUST AFTER 06Z AS THE FRONT MOVES THROUGH. EXPECTING A CHANGE OVER IN THE HIGHER ELEVATIONS WITH ALREADY TEMPS AT BLACK MOUNTAIN REACHING ITS HIGH FOR THE DAY IN THE UPPER 30S AND IS NOW BEGINNING TO DROP OFF AT THIS HOUR. MODEL PROFILES SHOW A BRIEF PERIOD OF GOOD OMEGA THROUGH THE LAST FEW HOURS OF THE EVENT AS THE FRONT MOVES THROUGH. WITH COLD ENOUGH AIR MOVING IN...THERE COULD BE SOME QUICK BURSTS OF SNOW IN THE HIGHER ELEVATIONS AND EVEN IN THE VALLEYS WHERE COLDER AIR HAS FINALLY MOVED IN. SPEAKING OF TEMPERATURES...LATE TONIGHT AND INTO THE DAY ON MONDAY...TEMPS WILL BE FALLING INTO THE MORNING HOURS BUT SOME SLIGHT RADIATIONAL HEATING DURING THE DAY BEFORE THE CORE OF THE AIR MASS MOVES IN MONDAY AFTERNOON AND INTO MONDAY NIGHT WILL RESULT IN TEMPS RISING A DEGREE OR TWO OR HOLDING STEADY THROUGH THE DAY TOMORROW. TEMPS OVER THE HIGHER TERRAIN SHOULD SLOWLY FALL THROUGH THE DAY. WINDS AFTER FRONTAL PASSAGE MONDAY MORNING WILL THEN SWITCH AROUND TO THE NORTHWEST FOR A FAVORABLE DIRECTION FOR SOME UPSLOPE SNOW SHOWERS THROUGH MONDAY AFTERNOON. MOISTURE DEPTH HANGS AROUND THROUGH MONDAY MORNING AND INTO THE AFTERNOON WITH SOME DECENT LIFT REMAINING ACCORDING TO THE NAM AND GFS SO SOME DECENT SNOW SHOWERS WILL HANG AROUND THROUGH THE DAY ON MONDAY BEFORE TAPERING OFF TO FLURRIES FROM WEST TO EAST INTO MONDAY NIGHT. THE CORE OF THE AIR MASS MOVING IN WILL CAUSE TEMPS TO PLUMMET INTO THE MID 20S MONDAY NIGHT AND WILL LIKELY ADD TO THE THREAT OF HAZARDOUS AND SLICK ROADS. THEREFORE...HAVE ISSUED AN SPS TO HIGHLIGHT THIS THREAT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 PM EST SUN JAN 25 2015 A RATHER AMPLIFIED PATTERN IS EXPECTED TO BEGIN THE PERIOD. MODELS REMAIN IN GENERALLY IN GOOD AGREEMENT FOR MOST OF THE PERIOD...WITH DIFFERENCES INCREASING TOWARD THE END OF THE PERIOD. AT THE START OF THE PERIOD A TROUGH IS EXPECTED TO BE IN PLACE FROM THE GREAT LAKES SOUTH INTO THE MID ATLANTIC SATES AND OFF THE SOUTHEASTERN US COAST...WITH A RIDGE OF HIGH PRESSURE FROM MEXICO NORTH INTO THE SOUTHERN PLAINS AND ROCKIES. AT THE SFC THE A DEEP SFC LOW/BLIZZARD WILL BE MOVING ALONG THE NORTHEAST US COAST TO START THE PERIOD WITH A RIDGE OF HIGH PRESSURE AT THE SFC EXTENDING FROM ONTARIO INTO THE GREAT LAKES AND MS VALLEY REGION. A SERIES OF SHORTWAVES IN NW FLOW BETWEEN THE TWO WILL DROP FROM THE GREAT LAKES AND THROUGH THE OH VALLEY AND APPALACHIANS TUESDAY INTO TUESDAY NIGHT. THIS WILL BRING CHANCES FOR SNOW SHOWERS AND REINFORCE A COLD AIRMASS WITH 850 MB TEMPS TO FALL TO THE -8C TO -10C RANGE BY LATE TUE AFTERNOON AND TUE EVENING. AS THE TROUGH AXIS LIFTS TO THE NORTH AND EAST AND THE SFC LOW MOVES FURTHER UP THE EASTERN SEABOARD...HIGH PRESSURE WILL GRADUALLY BUILD INTO THE LOWER OH VALLEY REGION AND APPALACHIANS TUE NIGHT INTO WED. THE INFLUENCE OF THE RIDGING WILL WANE BY LATE WED NIGHT AS A SHORTWAVE MOVING AROUND THE RIDGE OVER THE ROCKIES AND A NORTHERN STREAM TROUGH BEGIN TO JOIN FORCES AND APPROACH THE GREAT LAKES AND MS VALLEY REGION AS WELL AS THE LOWER OH VALLEY REGION. THE ASSOCIATED SFC LOW SHOULD TRACK WELL NORTH OF THE AREA JUST TO THE SOUTH OF THE SOUTHERN GREAT LAKES AND INTO THE MID ATLANTIC STATES FROM WED NIGHT INTO THU NIGHT. THIS SYSTEM WILL HAVE SOMEWHAT LIMITED MOISTURE...AND THIS SHOULD BE ANOTHER EVENT WHERE THE ATMOSPHERE MOISTENS FROM THE TOP DOWN. AT THE ONSET...SOME SNOW COULD MIX IN PENDING THE STRENGTH OF WARM AIR ADVECTION AND MOISTURE ADVECTION LATE WED NIGHT INTO THU MORNING. THE CLOUDS ALSO MAY NOT THICKEN QUICK ENOUGH TO PREVENT AT LEAST A MINOR RIDGE/VALLEY SPLIT FOR THE VALLEYS ON WED EVENING. AT THIS POINT...A LOW IN THE MID TO UPPER 20S OCCURRING AROUND 6Z ON THU IS EXPECTED. COLDER AIR WILL WRAP BACK INTO THE REGION BEHIND THIS SYSTEM AND POSSIBLY CHANGE ANY PRECIP BACK TO SNOW AS IT DEPARTS. HIGH PRESSURE SHOULD THEN BUILD IN TO BRING A DRY START TO THE WEEKEND. THE ECMWF LOWERS HEIGHTS MORE SIGNIFICANTLY ACROSS THE REGION AS WELL AS THE GREAT LAKES AND EASTERN SEABOARD AT THE END OF THE PERIOD AND IS THUS MUCH COLDER WITH THE AIRMASS. ANY SHORTWAVES AT THE END OF THE PERIOD SHOULD BE RATHER MOISTURE STARVED WITH THE MODEL CONSENSUS FAVORING ANYTHING THAT FALLS BEING SNOW. FOR TEMPS LATE IN THE PERIOD...OPTED TO GO A TAD COLDER THAN THE CONSENSUS BLEND...MORE IN LINE WITH ISC CONSENSUS AND GIVING A BIT MORE CREDIT TO THE PAST 2 ECMWF RUNS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 717 PM EST SUN JAN 25 2015 AVIATION CONCERNS WILL INCLUDE DROPPING CIGS THROUGH THIS EVENING AND INTO TONIGHT. WENT A BIT MORE OPTIMISTIC THROUGH ABOUT 6Z COMPARED TO THE PREVIOUS FORECAST...GIVEN THE SLOW MOVEMENT OF THE SYSTEM RESULTING IN A LONGER TIME FOR LOWER CIGS DOWNSTREAM TO REACH THE TAF SITES. EXPECT MVFR CIGS TO NOW REACH THE AREA BETWEEN 4 AND 7Z TONIGHT...SLOWLY DROPPING THROUGH THE NIGHT AND INTO THE MORNING AS THE HEAVIER PRECIP ARRIVES AND THE THE LOWER LEVELS MOISTEN UP. EXPECT AIRFIELD MINIMUM CIGS /OR JUST A COUPLE HUNDRED FEET ABOVE/ TO ARRIVE BETWEEN 12 AND 14Z AND REMAIN THROUGH MUCH OF THE AFTERNOON. IT IS ALSO AT THIS POINT THAT RAIN WILL LIKELY MAKE THE TRANSITION TO ALL SNOW AS TEMPS DROP BELOW FREEZING ACROSS THE REGION. LOWEST VISIBILITIES MAY ACTUALLY OCCUR DURING THIS CHANGEOVER PERIOD...BUT COULD FLUCTUATE ANYWHERE BETWEEN MVFR AND AIRPORT MINIMUMS DEPENDING ON THE INTENSITY OF THE BAND OF PRECIP PASSING OVERHEAD. WINDS THROUGH THE NIGHT WILL BEGIN TO SHIFT AROUND TO THE NORTHWEST WITH GUSTS UP TO 20 KNOTS POSSIBLE BY TOMORROW IN SOME LOCATIONS. SNOW SHOULD LIGHTEN UP AND TAPER OFF LATE IN THE TAF PERIOD WITH IMPROVING CONDITIONS EXPECTED...GENERALLY AFTER 18Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...SHALLENBERGER LONG TERM...JP AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
1138 PM EST SUN JAN 25 2015 .UPDATE... ISSUED AT 1137 PM EST SUN JAN 25 2015 GIVEN THE WELL ABOVE NORMAL TEMPERATURES EXPERIENCED TODAY /SOME LOCATIONS IN THE 50S/...WE JUST REALLY HAVEN/T SEEN A LARGE COOL DOWN ACROSS MUCH OF EASTERN KY THROUGH MOST OF THE EVENING. THIS IS ESPECIALLY TRUE IN AREAS THAT HAVE NOT YET RECEIVED RAIN...OR HAVE ONLY RECEIVED A SMALL AMOUNT. THIS BEING SAID...OTHER THAN ELEVATIONS ABOVE 3000 FT...DON/T EXPECT RAIN TO START CHANGING OVER QUITE AS FAST AS WHAT WAS IN THE PREVIOUS FORECAST. WORKED TO ADJUST THE LOW TEMPERATURE FOR OVERNIGHT...BASED ON THE LATEST MODEL GUIDANCE AND SOUNDINGS...AS WELL AS BASED ON THE ONGOING CONDITIONS WITH TEMPERATURES AND COOLING DOWNSTREAM...PREVIOUS SNOW PACK...ETC. WENT WITH A BLEND OF THE CURRENT FORECAST...THE LATEST HRRR /WHICH SEEMS TO HAVE THE BEST INITIALIZATION FOR THIS SYSTEM/...AND A LITTLE INFLUENCE FROM THE GFS...WHICH TRENDED CLOSER TO OVERALL THINKING FOR THE LOW. THEN...ADJUSTED INDIVIDUAL LOCATIONS TO GET THEM WITHIN BETTER TOLERANCE...INCLUDING BUMPING UP BLACK MOUNTAIN TO 29 DEGREES AND OTHER TERRAIN ABOVE 2500 FEET TO BETWEEN 30 AND 32 DEGREES. FURTHER MORE...GIVEN THE SLOW PROGRESS OF TEMPERATURES FALLING...WENT AHEAD AND PUSHED BACK THE TIMING OF THE LOW TEMPERATURE TO 13Z MONDAY. FROM HERE...USED A MIXTURE OF THE CONS-SHORT AND HAND EDITING TO ADJUST THE DIURNAL CURVE FOR THE REMAINDER OF THE NIGHT. ALL THINGS CONSIDERED...THE SLIGHT UPTICK IN TEMPERATURE FORECAST WILL RESULT IN A SEVERAL HOUR DIFFERENCE IN THE RAIN CHANGING OVER TO SNOW. THIS WILL KEEP ANY SNOW ACCUMULATIONS OUT OF THE FORECAST THROUGH 12Z /WITH THE EXCEPTION OF BLACK MOUNTAIN/...AND LESS SNOW ACCUMULATION IN FOR DURING THE DAY TOMORROW. BLACK MOUNTAIN IS CURRENTLY AT 32 DEGREES...SO THEY MAY START TO MIX WITH SNOW AT ANY TIME. HOWEVER...MOST OF THE REST OF THE AREA WILL LIKELY NOT SEE SNOW MIXING IN UNTIL NEAR DAWN...THEN SLOWLY TRANSITION TO ALL SNOW BETWEEN NOON AND 3PM. BY THIS POINT...MODEL SOUNDINGS ARE SHOWING A STRONG AMOUNT OF DRY AIR CUTTING OFF SOME OF THE BEST ACCUMULATION POTENTIAL DURING THE AFTERNOON. OVERALL...SNOW TOTALS WERE LOWERED ACROSS THE CWA. EXPECT ELEVATIONS ABOVE 3000 FEET TO PICK UP THE HIGHEST AMOUNTS...BETWEEN 1 AND 2 INCHES. SOME OF THE OTHER RIDGES ACROSS THE AREA COULD SEE BETWEEN A HALF AN ONE INCH...BUT A MAJORITY OF THE CWA WILL ONLY PICK UP A HALF INCH OR LESS. MOST OF THIS IS STILL EXPECTED TO FALL BETWEEN 12 AND 18Z WHEN THE BEST LIFT AND MOISTURE AND TEMPERATURES COMBINE. UPDATE ISSUED AT 706 PM EST SUN JAN 25 2015 FRESHENED UP THE GRIDS WITH THE LATEST OBSERVATIONAL DATA FOR TEMPS...DEW POINTS...AND WINDS. THIS RESULTED IN LITTLE OVERALL CHANGE FROM THE ONGOING FORECAST. BASED ON THE CURRENT RADAR RETURNS...AND THE PWAT VALUES OVERNIGHT BEING AROUND A HALF INCH OR LESS...WENT AHEAD AND REDUCED ANY MENTION OF MODERATE RAINFALL/SNOWFALL TO LIGHT. JUST NOT SEEING A WHOLE LOT OF EVIDENCE AT THIS POINT FOR MODERATE TO HEAVY INTENSITIES...THOUGH SNOW COULD HAVE SOME HEAVIER SPOTS AT TIMES TOMORROW MORNING. LATEST NAM12 FORECAST SOUNDINGS REALLY START TO LOSE MOISTURE IN THE UPPER LEVELS BETWEEN 6 AND 9 Z...WITH NOT MUCH LIFT EITHER...ALSO SUPPORTING LIGHTER INTENSITIES. OTHERWISE...FORECAST SEEMS TO BE IN PRETTY GOOD SHAPE OVER THE NEXT FEW HOURS. THE CENTER OF THE LOW IS CURRENTLY OVER SOUTH CENTRAL KY AND MOVING OUR DIRECTION...WITH THE NEXT ROUND OF LIGHT RAIN ABOUT TO SPREAD ACROSS THE CWA OVER THE NEXT 1 TO 2 HOURS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 409 PM EST SUN JAN 25 2015 SURFACE ANALYSIS AS OF 20Z ACROSS THE REGION FEATURES A SMALL LOW PRESSURE SYSTEM OVER THE LOWER MIDWEST TRACKING EAST INTO THE OH VALLEY THIS EVENING. AHEAD OF THIS...SOME SHOWER ACTIVITY HAS BEGUN TO MOVE INTO THE AREA THIS AFTERNOON WITH MORE WIDESPREAD PRECIP BACK WEST INTO WESTERN KENTUCKY AND SOUTHERN INDIANA. PLENTY OF SOUTHWEST FLOW TODAY AND WAA INTO THE AREA HAS ALLOWED FOR TEMPS TO RISE INTO THE UPPER 40S AND EVEN LOWER 50S ACROSS EASTERN KENTUCKY TODAY. MODELS SHOWING THE COLD FRONT TO MOVE THROUGH LATER TONIGHT AFTER 00Z WILL HAVE THE COLDER AIR MOVING IN LATER. THIS ADVECTION WILL BEGIN IN EARNEST JUST AFTER 06Z AS THE FRONT MOVES THROUGH. EXPECTING A CHANGE OVER IN THE HIGHER ELEVATIONS WITH ALREADY TEMPS AT BLACK MOUNTAIN REACHING ITS HIGH FOR THE DAY IN THE UPPER 30S AND IS NOW BEGINNING TO DROP OFF AT THIS HOUR. MODEL PROFILES SHOW A BRIEF PERIOD OF GOOD OMEGA THROUGH THE LAST FEW HOURS OF THE EVENT AS THE FRONT MOVES THROUGH. WITH COLD ENOUGH AIR MOVING IN...THERE COULD BE SOME QUICK BURSTS OF SNOW IN THE HIGHER ELEVATIONS AND EVEN IN THE VALLEYS WHERE COLDER AIR HAS FINALLY MOVED IN. SPEAKING OF TEMPERATURES...LATE TONIGHT AND INTO THE DAY ON MONDAY...TEMPS WILL BE FALLING INTO THE MORNING HOURS BUT SOME SLIGHT RADIATIONAL HEATING DURING THE DAY BEFORE THE CORE OF THE AIR MASS MOVES IN MONDAY AFTERNOON AND INTO MONDAY NIGHT WILL RESULT IN TEMPS RISING A DEGREE OR TWO OR HOLDING STEADY THROUGH THE DAY TOMORROW. TEMPS OVER THE HIGHER TERRAIN SHOULD SLOWLY FALL THROUGH THE DAY. WINDS AFTER FRONTAL PASSAGE MONDAY MORNING WILL THEN SWITCH AROUND TO THE NORTHWEST FOR A FAVORABLE DIRECTION FOR SOME UPSLOPE SNOW SHOWERS THROUGH MONDAY AFTERNOON. MOISTURE DEPTH HANGS AROUND THROUGH MONDAY MORNING AND INTO THE AFTERNOON WITH SOME DECENT LIFT REMAINING ACCORDING TO THE NAM AND GFS SO SOME DECENT SNOW SHOWERS WILL HANG AROUND THROUGH THE DAY ON MONDAY BEFORE TAPERING OFF TO FLURRIES FROM WEST TO EAST INTO MONDAY NIGHT. THE CORE OF THE AIR MASS MOVING IN WILL CAUSE TEMPS TO PLUMMET INTO THE MID 20S MONDAY NIGHT AND WILL LIKELY ADD TO THE THREAT OF HAZARDOUS AND SLICK ROADS. THEREFORE...HAVE ISSUED AN SPS TO HIGHLIGHT THIS THREAT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 420 PM EST SUN JAN 25 2015 A RATHER AMPLIFIED PATTERN IS EXPECTED TO BEGIN THE PERIOD. MODELS REMAIN IN GENERALLY IN GOOD AGREEMENT FOR MOST OF THE PERIOD...WITH DIFFERENCES INCREASING TOWARD THE END OF THE PERIOD. AT THE START OF THE PERIOD A TROUGH IS EXPECTED TO BE IN PLACE FROM THE GREAT LAKES SOUTH INTO THE MID ATLANTIC SATES AND OFF THE SOUTHEASTERN US COAST...WITH A RIDGE OF HIGH PRESSURE FROM MEXICO NORTH INTO THE SOUTHERN PLAINS AND ROCKIES. AT THE SFC THE A DEEP SFC LOW/BLIZZARD WILL BE MOVING ALONG THE NORTHEAST US COAST TO START THE PERIOD WITH A RIDGE OF HIGH PRESSURE AT THE SFC EXTENDING FROM ONTARIO INTO THE GREAT LAKES AND MS VALLEY REGION. A SERIES OF SHORTWAVES IN NW FLOW BETWEEN THE TWO WILL DROP FROM THE GREAT LAKES AND THROUGH THE OH VALLEY AND APPALACHIANS TUESDAY INTO TUESDAY NIGHT. THIS WILL BRING CHANCES FOR SNOW SHOWERS AND REINFORCE A COLD AIRMASS WITH 850 MB TEMPS TO FALL TO THE -8C TO -10C RANGE BY LATE TUE AFTERNOON AND TUE EVENING. AS THE TROUGH AXIS LIFTS TO THE NORTH AND EAST AND THE SFC LOW MOVES FURTHER UP THE EASTERN SEABOARD...HIGH PRESSURE WILL GRADUALLY BUILD INTO THE LOWER OH VALLEY REGION AND APPALACHIANS TUE NIGHT INTO WED. THE INFLUENCE OF THE RIDGING WILL WANE BY LATE WED NIGHT AS A SHORTWAVE MOVING AROUND THE RIDGE OVER THE ROCKIES AND A NORTHERN STREAM TROUGH BEGIN TO JOIN FORCES AND APPROACH THE GREAT LAKES AND MS VALLEY REGION AS WELL AS THE LOWER OH VALLEY REGION. THE ASSOCIATED SFC LOW SHOULD TRACK WELL NORTH OF THE AREA JUST TO THE SOUTH OF THE SOUTHERN GREAT LAKES AND INTO THE MID ATLANTIC STATES FROM WED NIGHT INTO THU NIGHT. THIS SYSTEM WILL HAVE SOMEWHAT LIMITED MOISTURE...AND THIS SHOULD BE ANOTHER EVENT WHERE THE ATMOSPHERE MOISTENS FROM THE TOP DOWN. AT THE ONSET...SOME SNOW COULD MIX IN PENDING THE STRENGTH OF WARM AIR ADVECTION AND MOISTURE ADVECTION LATE WED NIGHT INTO THU MORNING. THE CLOUDS ALSO MAY NOT THICKEN QUICK ENOUGH TO PREVENT AT LEAST A MINOR RIDGE/VALLEY SPLIT FOR THE VALLEYS ON WED EVENING. AT THIS POINT...A LOW IN THE MID TO UPPER 20S OCCURRING AROUND 6Z ON THU IS EXPECTED. COLDER AIR WILL WRAP BACK INTO THE REGION BEHIND THIS SYSTEM AND POSSIBLY CHANGE ANY PRECIP BACK TO SNOW AS IT DEPARTS. HIGH PRESSURE SHOULD THEN BUILD IN TO BRING A DRY START TO THE WEEKEND. THE ECMWF LOWERS HEIGHTS MORE SIGNIFICANTLY ACROSS THE REGION AS WELL AS THE GREAT LAKES AND EASTERN SEABOARD AT THE END OF THE PERIOD AND IS THUS MUCH COLDER WITH THE AIRMASS. ANY SHORTWAVES AT THE END OF THE PERIOD SHOULD BE RATHER MOISTURE STARVED WITH THE MODEL CONSENSUS FAVORING ANYTHING THAT FALLS BEING SNOW. FOR TEMPS LATE IN THE PERIOD...OPTED TO GO A TAD COLDER THAN THE CONSENSUS BLEND...MORE IN LINE WITH ISC CONSENSUS AND GIVING A BIT MORE CREDIT TO THE PAST 2 ECMWF RUNS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 717 PM EST SUN JAN 25 2015 AVIATION CONCERNS WILL INCLUDE DROPPING CIGS THROUGH THIS EVENING AND INTO TONIGHT. WENT A BIT MORE OPTIMISTIC THROUGH ABOUT 6Z COMPARED TO THE PREVIOUS FORECAST...GIVEN THE SLOW MOVEMENT OF THE SYSTEM RESULTING IN A LONGER TIME FOR LOWER CIGS DOWNSTREAM TO REACH THE TAF SITES. EXPECT MVFR CIGS TO NOW REACH THE AREA BETWEEN 4 AND 7Z TONIGHT...SLOWLY DROPPING THROUGH THE NIGHT AND INTO THE MORNING AS THE HEAVIER PRECIP ARRIVES AND THE THE LOWER LEVELS MOISTEN UP. EXPECT AIRFIELD MINIMUM CIGS /OR JUST A COUPLE HUNDRED FEET ABOVE/ TO ARRIVE BETWEEN 12 AND 14Z AND REMAIN THROUGH MUCH OF THE AFTERNOON. IT IS ALSO AT THIS POINT THAT RAIN WILL LIKELY MAKE THE TRANSITION TO ALL SNOW AS TEMPS DROP BELOW FREEZING ACROSS THE REGION. LOWEST VISIBILITIES MAY ACTUALLY OCCUR DURING THIS CHANGEOVER PERIOD...BUT COULD FLUCTUATE ANYWHERE BETWEEN MVFR AND AIRPORT MINIMUMS DEPENDING ON THE INTENSITY OF THE BAND OF PRECIP PASSING OVERHEAD. WINDS THROUGH THE NIGHT WILL BEGIN TO SHIFT AROUND TO THE NORTHWEST WITH GUSTS UP TO 20 KNOTS POSSIBLE BY TOMORROW IN SOME LOCATIONS. SNOW SHOULD LIGHTEN UP AND TAPER OFF LATE IN THE TAF PERIOD WITH IMPROVING CONDITIONS EXPECTED...GENERALLY AFTER 18Z. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...SHALLENBERGER LONG TERM...JP AVIATION...JMW
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
657 PM EST TUE JAN 27 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 426 PM EST TUE JAN 27 2015 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER THE CONUS...FEATURING A STRONG RIDGE OVER THE ROCKIES AND A DEEP TROF ALONG THE E COAST. RESULTING NW FLOW INTO THE GREAT LAKES IS QUIETER TODAY THAN YESTERDAY AS SUBTLE SHORTWAVE RIDGING IS JUST UPSTREAM OVER NRN ONTARIO. SO...THERE IS NO PCPN OF NOTE TODAY. THERE HAVE BEEN SOME -SHSN/FLURRIES OFF NRN LAKE MICHIGAN INTO MENOMINEE COUNTY...AND RECENTLY FLURRIES HAVE APPEARED ON KMQT RADAR IMAGERY IN CNTRL UPPER MI. AT THE SFC...HIGH PRES IS CENTERED OVER SRN QUEBEC WITH RIDGE EXTENDING BACK THRU THE UPPER LAKES. DRY AIR ASSOCIATED WITH THE HIGH HAS RESULTED IN A SUNNY DAY OVER ERN UPPER MI...ROUGHLY E OF A MUNISING-ESCANABA LINE. LOW CLOUDS HAVE BEEN PERSISTENT OVER THE REST OF THE AREA...THOUGH PORTIONS OF NW UPPER MI DID HAVE MOSTLY SUNNY SKIES EARLIER TODAY. QUIET WEATHER WILL CONTINUE TONIGHT WITH SHORTWAVE RIDGING PASSING ACROSS THE AREA. MAIN ISSUE WILL BE CLOUD TRENDS AND THE BIG IMPACT THE CLOUDS WILL HAVE ON TEMPS. WITH CLEAR SKIES AND LIGHT/CALM WIND TO START THE EVENING...THE ERN FCST AREA WILL BE COLDEST TONIGHT. LOWERED MINS TO AROUND 0F IN THAT AREA...BUT IT COULD BE 5 OR MORE DEGREES COLDER IF SKIES REMAIN CLEAR THRU THE WHOLE EVENING. OVERNIGHT...THERE WILL BE AN INCREASE IN CLOUDS DUE TO HIGH CLOUDS STREAKING SE WELL AHEAD OF THE NEXT SHORTWAVE MOVING ACROSS THE SRN CANADIAN ROCKIES AND POSSIBLY FROM LOW CLOUDS ADVECTING NE IN DEVELOPING SW FLOW. THIS WILL PUT THE BRAKES ON COOLING AND PROBABLY LEAD TO TEMPS RISING SOME OVERNIGHT. ACROSS THE REST OF THE FCST AREA...THE EXPANSE OF LOW CLOUDS EXTENDING W...SW AND S OVER MUCH OF MN AND WI SUGGESTS CLOUDS WILL DOMINATE FOR MUCH OF THE NIGHT UNDER LOW-LEVEL S TO SW WINDS. EVEN IF LOW CLOUDS CLEAR OUT IN SOME AREAS...HIGH AND MID CLOUDS WILL BE OVERSPREADING THE AREA. LOWS SHOULD GENERALLY BE IN THE 15-20F RANGE. ON WED....ONE SHORTWAVE WILL MOVE FROM THE SRN CANADIAN ROCKIES INTO THE DAKOTAS/MANITOBA WHILE A SECOND MOVES FROM WY/CO TO THE CNTRL PLAINS. AHEAD OF THE NRN WAVE...WAA/ISENTROPIC ASCENT WILL STRENGTHEN AND SHIFT ESE THRU THE DAY UNDERNEATH RIGHT ENTRANCE OF UPPER JET. WITH THE FOCUS OF MOIST ISENTROPIC ASCENT JUST TO THE N AND WITH DRIER AIR HOLDING ON AT LOW LEVELS...THE MAIN STREAK OF SNOW WILL REMAIN N OF HERE WED AFTN. MODEL AGREEMENT IS IN EXCELLENT AGREEMENT ON THIS POINT. HOWEVER...THERE IS SOME UNCERTAINTY IN WHETHER THE SRN EDGE OF THE SNOW MAY CLIP THE AREA. BASED ON STRENGTH OF ISENTROPIC ASCENT AND TEMP/MOISTURE PROFILES ON FCST SOUNDINGS...THE KEWEENAW AND FAR ERN FCST AREA MAY GET CLIPPED BY A LITTLE -SN. INCLUDED ONLY SCHC/LOW CHC POPS TO REFLECT THIS POTENTIAL. OTHERWISE...EXPECT A WARMER DAY WITH HIGHS IN THE UPPER 20S/LWR 30S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 313 PM EST TUE JAN 27 2015 AN UPPER RIDGE OVER THE WESTERN COAST OF NORTH AMERICA AND AN UPPER LOW OVER HUDSON BAY WILL KEEP NORTHWEST FLOW OVER THE UPPER GREAT LAKES REGION FOR MUCH OF THE LONG TERM PERIOD. THIS WILL LEAD TO SEVERAL SHORTWAVES DROPPING SOUTHEAST ACROSS THE REGION...WHILE THE UPPER LOW OVER HUDSON BAY GRADUALLY SINKS SOUTH TOWARDS THE AREA. THUS...EXPECT GRADUALLY COOLING TEMPERATURES THROUGH EARLY NEXT WEEK. THREE PIECES OF ENERGY WITHIN THE LARGER SHORTWAVE TROUGH MOVING THROUGH THE UPPER GREAT LAKES REGION WEDNESDAY NIGHT AND THURSDAY WILL BE DRIVING THE WEATHER FOR THE START OF THE LONG TERM PERIOD. THE SOUTHERN TWO WAVES WILL BE SUPPORTING THE SURFACE LOW MOVING THROUGH SOUTHERN WISCONSIN AND THE INVERTED TROUGH CROSSING THE UPPER GREAT LAKES REGION. AT THE START OF THE LONG TERM PERIOD...EXPECT THE HEAVIEST PRECIPITATION TO BE ONGOING OVER NORTHERN ONTARIO AND FAR NORTHERN LAKE SUPERIOR...WHILE THERE WILL BE SOME SNOW OVER EASTERN UPPER MICHIGAN TIED TO THE NOSE OF THE 850-700MB WARM AIR ADVECTION INTERACTING WITH THE DEEPER MOISTURE. THINKING MUCH OF THE REST OF THE AREA WILL BE SEEING LIMITED PRECIPITATION CHANCES WITH THE POCKET OF DRY AIR BETWEEN 925-750MB. THEN AS THE 850-700MB TROUGH SWEEPS SOUTHEAST THROUGH THE AREA THROUGH THE NIGHT...EXPECT SNOW TO QUICKLY SPREAD INTO THE AREA THROUGH THE EVENING/OVERNIGHT HOURS. WITH THAT INITIAL PRECIPITATION STAYING TO THE NORTH OF THE LAND AREA INITIALLY...HAVE TRENDED QPF/SNOW AMOUNTS DOWN SLIGHTLY OVER THE WEST/CENTRAL (1-2IN). NORTHEAST OF A LINE FROM HOUGHTON TO MANISTIQUE...HAVE AMOUNTS IN THE 2-3.5 INCH RANGE AND WILL CONTINUE TO MENTION IN THE HWO FOR THOSE AREAS. AS THE DEEPER MOISTURE DEPARTS THURSDAY MORNING...WILL SEE THE SNOW DIMINISH...BUT THINK THERE WILL BE ENOUGH TERRAIN INFLUENCE TO HELP KEEP SNOW SHOWERS IN THE NORTH-NORTHWESTERLY WIND SNOW BELTS UNTIL THE COLD AIR ARRIVES THURSDAY AFTERNOON AND INCREASES DELTA-T VALUES TOWARDS THE LOW 20S BY THURSDAY EVENING. THERE ARE HINTS OF LIMITED ICE CRYSTALS (AND THUS FREEZING DRIZZLE) OVER THE WEST AS THAT DEEP MOISTURE DEPARTS...BUT THINK IT IS TOO MARGINAL TO MENTION AT THIS POINT. WITH THAT COLD AIR ARRIVING FROM NORTHWEST TO SOUTHEAST ON THURSDAY AFTERNOON/EVENING...SHOULD SEE LAKE EFFECT COVERAGE INCREASING DURING THAT TIME FRAME. WILL TREND POPS UP TO LIKELY/DEFINITE VALUES FOR THE FAVORED NORTHWEST WIND SNOW BELTS FOR THURSDAY NIGHT. WHILE SNOW IS EXPECTED...THERE ARE A COUPLE LIMITING FACTORS FOR HIGHER SNOWFALL AMOUNTS. FIRST...THE APPROACHING HIGH PRESSURE RIDGE WILL KEEP THE SUBSIDENCE INVERSION AROUND 5KFT THROUGH THE PERIOD. WHILE MUCH OF THE CLOUD WILL BE IN OR JUST ABOVE THE DGZ...THINK THE FRACTURING OF THE FLAKES FROM THE GUSTY WINDS WILL KEEP SNOW RATIOS LOWER (BUT BE BETTER AT REDUCING VISIBILITIES). THUS...HAVE SNOWFALL AMOUNTS OF 1-4 INCHES IN THE FAVORED SNOW BELTS DURING THAT PERIOD. AS THE HIGH MOVES JUST SOUTH OF THE AREA ON FRIDAY...EXPECT WINDS TO BACK TOWARDS THE WEST AND LOWER THE SUBSIDENCE INVERSION TOWARDS 4KFT. THEREFORE...WILL GRADUALLY DIMINISH PRECIPITATION CHANCES THROUGH FRIDAY AS WINDS BACK TO THE SOUTHWEST ON FRIDAY NIGHT. THE NEXT CLIPPER WILL SWEEP ACROSS THE AREA SATURDAY AND DRAG A WEAK SURFACE TROUGH WITH IT. STILL SOME DIFFERENCES IN THE TIMING WITH THIS FEATURE...SO WILL GO WITH LOW END CHANCE POPS SPREADING ACROSS THE CWA ON SATURDAY. OVERALL...LOOKS LIKE JUST A QUICK DUSTING OF SNOW WITH THIS FEATURE. BEHIND THE TROUGH...COLD AIR WILL FILTER BACK INTO THE UPPER GREAT LAKES REGION AND BRING ANOTHER PERIOD OF LAKE EFFECT FOR THE NORTH-NORTHWEST WIND SNOWBELTS. ONCE AGAIN...THE HIGH PRESSURE RIDGE NOSING EAST INTO THE AREA WILL KEEP THE SUBSIDENCE INVERSION AROUND 5KFT AND KEEP THE LAKE EFFECT AMOUNTS ON THE LIGHT SIDE. ONE ITEM TO WATCH IS THE POTENTIAL FOR A WEAK SHORTWAVE SLIDING ACROSS THE AREA ON MONDAY. THERE ARE HINTS THAT THIS MAY RAISE INVERSION HEIGHTS TOWARDS 7-10KFT...WHICH WOULD PROVIDE THE POTENTIAL FOR MODERATE LAKE EFFECT. WHEN THAT OCCURS...WITH ANOTHER SURGE OF COLD AIR (850MB TEMPS FALLING TO THE MID -20S) THE CLOUD WILL BE WELL ABOVE THE DGZ AND SUPPORT SMALL FLAKES THAT ARE HIGHLY EFFICIENT AT REDUCING VISIBILITY. WITH THE HIGH MOVING SOUTHEAST FROM THE NORTHERN PLAINS ON MONDAY MORNING TO THE OHIO RIVER VALLEY ON TUESDAY...EXPECT GRADUALLY BACKING WINDS OVER LAKE SUPERIOR AND WILL FOLLOW THAT IDEA FOR AT LEAST LIKELY POPS FOR THE FAVORED WIND DIRECTIONS THROUGH TUESDAY (WINDS NEAR WESTERLY BY TUESDAY EVENING). WON/T MENTION IN THE HWO AT THIS POINT...AS AMOUNTS WILL BE ON THE LOW SIDE...BUT MAY NEED TO ADDRESS THE END OF THE WEEK LAKE EFFECT AND THE SUN-TUE LAKE EFFECT IN THE FUTURE DUE TO THE LIKELY LOW VISIBILITIES IN THE STRONGER BANDS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 651 PM EST TUE JAN 27 2015 BASED ON UPSTREAM CLOUDS OVER MUCH OF WI AND MN AND ALSO MID CLOUDS SPREADING ACROSS THE UPPER LAKES FROM ONTARIO...LOW CLOUDS ACROSS MUCH OF WEST AND CENTRAL UPPER MI MAY BE SLOW TO DEPART. EXPECT MVFR CONDITIONS TO PERSIST AT ALL THE TAF SITES THROUGH THE FCST PD. THERE MAY BE SLIGHT IMPROVEMENT TO HIGH END MVFR BY LATE WED MORNING AND AFTERNOON WITH INCREASED MIXING FROM SOUTH WINDS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 426 PM EST TUE JAN 27 2015 WINDS WILL REMAIN UNDER 20KT TONIGHT/WED. LOW PRES WILL THEN TRACK FROM THE MID AND UPPER MISSISSIPPI VALLEY WED EVENING TO THE LOWER LAKES BY LATE THU EVENING. AHEAD OF THE LOW...S WINDS WILL INCREASE FOR A TIME WED NIGHT...MAINLY OVER ERN LAKE SUPERIOR WHERE WINDS WILL REACH 20-30KT. BEHIND THE LOW ON THU...N TO NW WINDS WILL INCREASE TO 20-30KT OVER WRN LAKE SUPERIOR. OVER THE CNTRL AND ERN LAKE...WINDS WILL INCREASE TO GALE FORCE FOR THU AFTN AND NIGHT. COMBINATION OF MUCH COLDER AIR/STRONG WINDS AND BUILDING WAVES WILL LEAD TO HVY FREEZING SPRAY THU AFTN UNTIL LATE FRI MORNING WHEN WINDS/WAVES DIMINISH WITH THE CLOSER APPROACH OF CANADIAN HIGH PRES. AFTER A PERIOD OF LIGHTER WINDS MOSTLY UNDER 20KT FRI INTO SAT MORNING...N WINDS WILL INCREASE TO 20-30KT LATER SAT INTO SUN IN THE WAKE OF A LOW PRES TROUGH. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...VOSS MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
437 PM EST MON JAN 26 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 434 PM EST MON JAN 26 2015 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER NAMERICA...FEATURING A RIDGE OVER THE WRN CONUS INTO SW CANADA AND A TROF OVER THE E. RESULTING NW FLOW INTO THE GREAT LAKES IS CARRYING SEVERAL MINOR DISTURBANCES TO THE SE...AND THIS HAS LED TO BKN PCPN EXTENDING FROM IL/IN NNW INTO NRN ONTARIO PER REGIONAL RADAR IMAGERY. IR IMAGERY SHOWS ONE DIMINISHING AREA OF ENHANCED CLOUDS NOW SSE OF UPPER MI AND A SECOND AREA DROPPING SSE TOWARD LAKE SUPERIOR. THE ENHANCED CLOUDS WITH THE APPROACHING SHORTWAVE HAVE NOT CHANGED MUCH OVER THE LAST SEVERAL HRS...AND ENVIRONMENT CANADA RADAR NEAR THUNDER BAY SHOWS A DECENT AREA OF ASSOCIATED SNOW APPROACHING NW LAKE SUPERIOR. TO THE SE...AN AREA OF ENHANCED CONVERGENCE OVER LAKE MI AT THE LEADING EDGE OF STRONGER SE WINDS LED TO SOME SNOW SPREADING OFF LAKE MI INTO DELTA AND ALGER COUNTIES TODAY. ON VIS SATELLITE IMAGERY...HIGH CLOUDS HAVE THINNED JUST ENOUGH TO SEE THAT THERE IS LITTLE IN THE WAY OF LAKE EFFECT CLOUDS REMAINING ON NRN LAKE MI NOW. SHORTWAVE OFF TO THE NW WILL DIVE SE ACROSS UPPER MI TONIGHT. GIVEN THE ENHANCED CLOUDS JUST NNW OF THE AREA...SNOW DEPICTED ON UPSTREAM RADAR IMAGERY NEAR THUNDER BAY AND MODEST DEEP LAYER QVECTOR CONVERGENCE INDICATED BY MODELS...EXPECT ANOTHER AREA OF STEADIER -SN TO SPREAD SSE ACROSS THE WRN AND CNTRL FCST AREA THIS EVENING. ERN EDGE OF THE FORCING WILL BE UP AGAINST A STEADY FEED OF LOW- LEVEL DRY AIR EMANATING FROM HIGH PRES CENTERED OVER SOUTHERN QUEBEC. THIS IS CERTAINLY EVIDENT IN NAM/GFS/RUC13 FCST SOUNDINGS WHICH MAINTAIN A DRY WEDGE IN ROUGHLY THE 2-5KFT LAYER...AND HIGH RES MODELS SHOW PCPN STAYING W OF ROUGHLY A KISQ/SHINGLETON LINE WITH ONLY THE GEM GETTING PCPN CLOSE TO KERY. THUS...WILL NOT INCLUDE ANY SNOW IN THE FCST OVER THE FAR E TONIGHT. THAT SAID...THE ONLY POTENTIAL ISSUE WOULD BE FOR A COUPLE OF THE LES BANDS OFF NRN LAKE HURON TO STREAK WNW INTO LUCE COUNTY FOR A TIME TONIGHT. BACK TO THE W...HIGH RES MODELS SHOW PCPN AMOUNTS IN THE 0.03 TO 0.1 INCH RANGE TONIGHT...FALLING ALMOST ENTIRELY BEFORE 06Z. WITH SLR PROBABLY AROUND 17 TO 1...THIS SUGGESTS SNOW AMOUNTS OF 0.5 TO NEARLY 2 INCHES. WITH LOW-LEVEL SE WINDS PROVIDING UPSLOPING/MOISTENING OFF LAKE MICHIGAN...THE HIGHER SNOW AMOUNTS SHOULD OCCUR ROUGHLY IN THE AREA S OF A LINE FROM IRON RIVER TO NEGAUNEE TO ESCANABA. AS FOR TEMPS...BIGGEST CHALLENGE IS OVER THE FAR E WHERE CLOUDS MAY THIN OUT ENOUGH LATE IN THE NIGHT FOR TEMPS TO PLUMMET UNDER LIGHT/CALM WIND. FOR NOW...INDICATED MINS NEAR ZERO IN THAT AREA. QUIET DAY ON THE WAY FOR TUE WITH SFC HIGH PRES RIDGE OVER UPPER MI. WHILE THE E WILL PROBABLY ENJOY A MOSTLY SUNNY DAY...LOW CLOUDS WILL LIKELY TAKE SOME TIME TO SCATTER OUT OVER THE W AND CNTRL. EXPECT HIGHS RANGING FROM THE LWR 20S E TO THE UPPER 20S W. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 437 PM EST MON JAN 26 2015 THERE WILL BE MINOR FLUCTUATIONS IN THE UPPER RIDGE ALONG THE WESTERN COAST OF NORTH AMERICA...BUT IT WILL LARGELY STAY IN PLACE THROUGH THE LONG TERM FORECAST. THIS WILL LEAD TO NORTHWESTERLY FLOW ALOFT OVER THE UPPER GREAT LAKES REGION AND SEND A SERIES OF SHORTWAVES THROUGH THE AREA. THE UPPER GREAT LAKES REGION WILL BE UNDER WEAK RIDGING WITHIN THE NORTHWESTERLY FLOW ALOFT TO START THE PERIOD...WHILE THE SURFACE RIDGE WILL BE SLIDING EAST OF THE AREA. EXPECT THERE TO BE SOME LINGERING LOWER CLOUDS OVER THE CENTRAL PART OF THE CWA...WHILE THERE WILL BE HIGH CLOUDS SPREADING OVER THE WESTERN CWA AHEAD OF THE NEXT SYSTEM. THESE CLOUDS WILL KEEP TEMPS FROM FALLING TOO MUCH IN THAT AREA...BUT OVER THE EAST...CLEARING IN THE EVENING WILL ALLOW TEMPERATURES TO QUICKLY FALL INTO THE LOWER SINGLE DIGITS ABOVE ZERO. DID TREND TOWARDS THE BETTER PERFORMING GEM MODELS OVER THE EAST IN THOSE CLEAR SKY AND RADIATIONAL COOLING SITUATIONS. FOCUS THEN TURNS TO THE INVERTED TROUGH PUSHING EAST TOWARDS THE AREA ON WEDNESDAY (FROM A LOW MOVING OUT OF THE NORTHERN/CENTRAL PLAINS) AND THREE SHORTWAVES THAT WILL COME TOGETHER OVER THE GREAT LAKES REGION THROUGH THURSDAY. THE INITIAL AREA OF PRECIPITATION SHOULD STAY WELL TO THE NORTH OF UPPER MICHIGAN ON WEDNESDAY (TIED TO THE DEEPER MOISTURE AND BROAD WARM AIR ADVECTION OVER NORTHERN LAKE SUPERIOR. BUT AS A SECOND SHORTWAVE SLIDES SOUTHEAST INTO THE AREA FROM MANITOBA ON WEDNESDAY NIGHT...EXPECT THE PRECIPITATION SWEEP SOUTH THROUGH THE AREA WITH THE 850-700MB TROUGH. SHOULD SEE 1-3 INCHES OF SNOW MOVE ACROSS THE AREA ON WEDNESDAY NIGHT...WITH THE HIGHEST AMOUNTS OVER THE EAST. COLDER AIR IS DELAYED BEHIND THE SYSTEM...SO DON/T EXPECT MUCH IN THE WAY OF LAKE ENHANCEMENT...BUT DID FACTOR IN SOME TERRAIN ENHANCEMENT FOR THURSDAY. WITH THAT LACK OF COLD AIR...THE CLOUD THERMAL PROFILE IS ON THE EDGE FOR ICE CRYSTALS. AT THIS POINT...THINK THERE WILL BE ENOUGH AND LEFT OUT FREEZING DRIZZLE...BUT IT WILL BE SOMETHING TO WATCH. THE COLD AIR FINALLY ARRIVES ON THURSDAY NIGHT AND REMAINS INTO FRIDAY UNDER NORTH-NORTHWEST WINDS ALOFT. EXPECT LIGHT LAKE EFFECT TO OCCUR IN THOSE SNOW BELTS...BUT WITH SUBSIDENCE FROM HIGH PRESSURE BUILDING INTO THE UPPER MISSISSIPPI VALLEY...INVERSION HEIGHTS WILL STRUGGLE TO RISE MUCH ABOVE 4-5KFT. THUS...THINK ACCUMULATIONS WILL BE ON THE LOW SIDE...BUT THEY WILL BE EFFICIENT AT REDUCING VISIBILITIES DUE TO THE CLOUD BEING ABOVE THE DGZ. WINDS WILL BACK ON FRIDAY AFTERNOON/NIGHT AS THE HIGH SLIDES JUST TO THE SOUTH OF THE AREA. FORECAST BECOMES A LITTLE UNCERTAIN AS MODELS DIVERGE ON THE UPPER LEVEL FEATURES. ALL IN ALL...LOOKS LIKE A WEAK TROUGH WILL SLIDE ACROSS THE AREA ON SATURDAY AND USHER IN ANOTHER SURGE OF COLD AIR (MID -20S 850MB TEMPS) INTO THE UPPER GREAT LAKES REGION. WILL CONTINUE TO SHOW LAKE EFFECT POPS BEHIND THAT TROUGH IN THE NW WIND SNOW BELTS FOR SATURDAY NIGHT INTO MONDAY. WITH THE AMOUNT OF COLD AIR...EXPECT LIMITED SNOWFALL AMOUNTS BUT GOOD VISIBILITY RESTRICTION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1249 PM EST MON JAN 26 2015 IN THE WAKE OF STEADIER SNOW THAT AFFECTED KIWD THIS MORNING... EXPECT MVFR CONDITIONS TO PREVAIL THIS AFTN. ANOTHER DISTURBANCE TRACKING SSE WILL BRING A ROUND OF -SN TO KIWD/KCMX/KSAW LATE THIS AFTN/EVENING. WHILE KIWD SHOULD REMAIN MVFR AS THE -SN PASSES...STEADIER SNOW AT KCMX/KSAW WILL LIKELY DROP CONDITIONS FROM VFR TO IFR. LINGERING MOISTURE BEHIND THE DISTURBANCE WILL RESULT IN CONDITIONS FALLING TO IFR AT KIWD BY LATE EVENING. IFR/LOW MVFR CIGS WILL LIKELY PERSIST AT ALL TERMINALS THRU TUE MORNING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 434 PM EST MON JAN 26 2015 WITH WEAK LOW PRES OVER NE MN DROPPING SSE TONIGHT...STRONGER S WINDS OF 20-30KT WILL CONTINUE OVER ERN LAKE SUEPRIOR THRU THIS EVENING BEFORE DIMINISHING OVERNIGHT. WITH WEAKER PRES GRADIENT OVER THE W...WINDS WILL BE UNDER 20KT. WINDS WILL THEN BE UNDER 20KT ACROSS THE ENTIRE LAKE TUE/WED AS HIGH PRES RIDGE DRIFTS SSE FROM THE UPPER LAKES. LOW PRES WILL THEN TRACK FROM THE MID MISSISSIPPI VALLEY WED NIGHT TO THE LOWER LAKES THU NIGHT. BEHIND THE LOW...N TO NW WINDS WILL INCREASE TO 20-30KT THU/THU NIGHT WITH GALES POSSIBLE OVER THE E HALF OF THE LAKE. WINDS WILL THEN DIMINISH FRI AS HIGH PRES PASSES ACROSS THE WRN GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
435 PM EST MON JAN 26 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 434 PM EST MON JAN 26 2015 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER NAMERICA...FEATURING A RIDGE OVER THE WRN CONUS INTO SW CANADA AND A TROF OVER THE E. RESULTING NW FLOW INTO THE GREAT LAKES IS CARRYING SEVERAL MINOR DISTURBANCES TO THE SE...AND THIS HAS LED TO BKN PCPN EXTENDING FROM IL/IN NNW INTO NRN ONTARIO PER REGIONAL RADAR IMAGERY. IR IMAGERY SHOWS ONE DIMINISHING AREA OF ENHANCED CLOUDS NOW SSE OF UPPER MI AND A SECOND AREA DROPPING SSE TOWARD LAKE SUPERIOR. THE ENHANCED CLOUDS WITH THE APPROACHING SHORTWAVE HAVE NOT CHANGED MUCH OVER THE LAST SEVERAL HRS...AND ENVIRONMENT CANADA RADAR NEAR THUNDER BAY SHOWS A DECENT AREA OF ASSOCIATED SNOW APPROACHING NW LAKE SUPERIOR. TO THE SE...AN AREA OF ENHANCED CONVERGENCE OVER LAKE MI AT THE LEADING EDGE OF STRONGER SE WINDS LED TO SOME SNOW SPREADING OFF LAKE MI INTO DELTA AND ALGER COUNTIES TODAY. ON VIS SATELLITE IMAGERY...HIGH CLOUDS HAVE THINNED JUST ENOUGH TO SEE THAT THERE IS LITTLE IN THE WAY OF LAKE EFFECT CLOUDS REMAINING ON NRN LAKE MI NOW. SHORTWAVE OFF TO THE NW WILL DIVE SE ACROSS UPPER MI TONIGHT. GIVEN THE ENHANCED CLOUDS JUST NNW OF THE AREA...SNOW DEPICTED ON UPSTREAM RADAR IMAGERY NEAR THUNDER BAY AND MODEST DEEP LAYER QVECTOR CONVERGENCE INDICATED BY MODELS...EXPECT ANOTHER AREA OF STEADIER -SN TO SPREAD SSE ACROSS THE WRN AND CNTRL FCST AREA THIS EVENING. ERN EDGE OF THE FORCING WILL BE UP AGAINST A STEADY FEED OF LOW- LEVEL DRY AIR EMANATING FROM HIGH PRES CENTERED OVER SOUTHERN QUEBEC. THIS IS CERTAINLY EVIDENT IN NAM/GFS/RUC13 FCST SOUNDINGS WHICH MAINTAIN A DRY WEDGE IN ROUGHLY THE 2-5KFT LAYER...AND HIGH RES MODELS SHOW PCPN STAYING W OF ROUGHLY A KISQ/SHINGLETON LINE WITH ONLY THE GEM GETTING PCPN CLOSE TO KERY. THUS...WILL NOT INCLUDE ANY SNOW IN THE FCST OVER THE FAR E TONIGHT. THAT SAID...THE ONLY POTENTIAL ISSUE WOULD BE FOR A COUPLE OF THE LES BANDS OFF NRN LAKE HURON TO STREAK WNW INTO LUCE COUNTY FOR A TIME TONIGHT. BACK TO THE W...HIGH RES MODELS SHOW PCPN AMOUNTS IN THE 0.03 TO 0.1 INCH RANGE TONIGHT...FALLING ALMOST ENTIRELY BEFORE 06Z. WITH SLR PROBABLY AROUND 17 TO 1...THIS SUGGESTS SNOW AMOUNTS OF 0.5 TO NEARLY 2 INCHES. WITH LOW-LEVEL SE WINDS PROVIDING UPSLOPING/MOISTENING OFF LAKE MICHIGAN...THE HIGHER SNOW AMOUNTS SHOULD OCCUR ROUGHLY IN THE AREA S OF A LINE FROM IRON RIVER TO NEGAUNEE TO ESCANABA. AS FOR TEMPS...BIGGEST CHALLENGE IS OVER THE FAR E WHERE CLOUDS MAY THIN OUT ENOUGH LATE IN THE NIGHT FOR TEMPS TO PLUMMET UNDER LIGHT/CALM WIND. FOR NOW...INDICATED MINS NEAR ZERO IN THAT AREA. QUIET DAY ON THE WAY FOR TUE WITH SFC HIGH PRES RIDGE OVER UPPER MI. WHILE THE E WILL PROBABLY ENJOY A MOSTLY SUNNY DAY...LOW CLOUDS WILL LIKELY TAKE SOME TIME TO SCATTER OUT OVER THE W AND CNTRL. EXPECT HIGHS RANGING FROM THE LWR 20S E TO THE UPPER 20S W. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 105 AM EST MON JAN 26 2015 WITH THE 500MB LOW AND THE AXIS OF THE 500MB TROUGH SHIFTED OVER THE NEW ENGLAND STATES TUESDAY...THE RIDGE CURRENTLY OVER THE W HALF OF THE NATION WILL BE ABLE TO SHIFT ACROSS THE CENTRAL PLAINS AND UPPER GREAT LAKES TUESDAY INTO EARLY WEDNESDAY. AT THE SFC...A RIDGE WILL BE ABLE TO SLIDE ACROSS LAKE SUPERIOR TUESDAY /EXTENDING FROM MN UP THROUGH NEWFOUNDLAND/...WHICH WILL LINGER INTO TUESDAY NIGHT AS THE MAIN AREA OF HIGH PRESSURE PUSHES INTO THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE RESULT WILL BE A DRY PERIOD AT LEAST UNTIL MID DAY WEDNESDAY...ALTHOUGH THERE MAY STILL BE SOME CLOUDS LINGERING/STUCK BELOW THE 850-900MB SUBSIDENCE INVERSION. TRICKY CLOUD COVER FCST FOR THIS PERIOD. WEDNESDAY LOOK TO BE THE LAST WARM DAY IN A WHILE...WITH TEMPERATURES NEAR FREEZING. 850MB TEMPS ON S FLOW WILL RISE TO -1 TO -4C THROUGH THE DAYTIME HOURS AS THICKER CLOUDS INVADE FROM THE NW. AN ELONGATED AREA OF LOW PRESSURE OVER THE N AND CENTRAL PLAINS WEDNESDAY MORNING WILL EDGE E ACROSS IL AND IN THURSDAY MORNING...AND OFF TO THE LOWER GREAT LAKES AND OFF THE MID ATLANTIC STATES FRIDAY. THIS WILL BRING A TROUGH ACROSS OUR AREA WEDNESDAY NIGHT THROUGH THURSDAY EVENING...WHICH WILL BE ENHANCED BY THE SUPPRESSION OF THE 500MB RIDGE WEDNESDAY EVENING AND THURSDAY. LOOK FOR A WIDESPREAD 2-5IN OF SNOW WITH SLR VALUES AROUND 15:1. EXPECT THE HIGHER VALUES OVER THE N HALF OF UPPER MI AS IT WILL LIKELY TAKE UNTIL LATE AFTERNOON/EARLY EVENING FOR SNOW TO BEGIN S CENTRAL. WILL NOT GO QUITE AS QUICK WITH THE INVADING PRECIP AS THE 00Z NAM...BUT A BLENDED SOLUTION SOUNDS REASONABLE. A WINTER WX ADVISORY MAY BE NEEDED IF THE 2-5IN CAN FALL IN A 12HR PERIOD. WILL CONTINUE TO LOOK INTO THIS FOR POSSIBLE POSTING OF HEADLINES ON TUESDAY...AND HIGHLIGHT THE POTENTIAL FOR LIGHT TO MODERATE SNOW IN THE HWO. N FLOW BEHIND THE EXITING SFC TROUGH THURSDAY AFTERNOON WILL BE THE START OF OUR COOL DOWN...WITH 850MB TEMPS FALLING TO -8 TO -10C. WHILE NOT QUITE OPTIMAL FOR LAKE EFFECT YET...SOME LAKE ENHANCEMENT WILL BE LIKELY ALONG THE UPSLOPE N SNOWBELTS ALONG LAKE SUPERIOR THURSDAY AS THE SFC LOW EXITS TO THE LOWER GREAT LAKES/PENNSYLVANIA FRIDAY EVENING. DESPITE SFC-500MB RIDGING ON FRIDAY...A FEW LINGERING LES WILL REMAIN ALONG THE LAKE SUPERIOR SHORELINES. DON/T EXPECT MUCH IN THE WAY OF ACCUMULATIONS AS THE MOISTURE IS AGAIN TRAPPED BELOW 850MB. BUT WILL THE MOISTURE LAYER IN THE DGZ /850MB TEMPS OF -15 TO -17C/...SOME LIGHT ACCUMULATIONS WILL BE POSSIBLE. SLIGHTLY WARMER AIR WILL PUSH IN THROUGH EARLY SATURDAY MORNING AS THE SFC RIDGE EXITS TO THE LOWER GREAT LAKES...AND IN ADVANCE OF LOW PRESSURE DEVELOPING NEARING FROM THE N PLAINS STATES. SOME OF THE COLDEST AIR OF THE SEASON WILL PUSH INTO THE UPPER GREAT LAKES SATURDAY AFTERNOON ON. THERE CONTINUES TO BE SOME TIMING ISSUES ON THE ORDER OF AROUND 6HRS...WHICH IS PRETTY MINOR THIS FAR OUT IN THE FCST...AND A BLENDED SOLUTION LOOKS REASONABLE. 850MB TEMPS OF -20 TO -30C WILL SETTLE IN SUNDAY AFTERNOON AS THE SFC LOW EXITS AND THE MAIN 500MB TROUGH PUSHES ACROSS THE UPPER GREAT LAKES. LOOK FOR FINE LES THAT WILL BE GOOD AT REDUCING VIS...ESPECIALLY IF THE STRONGER NW WINDS OF THE 25/12Z ECMWF ARE CORRECT/. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1249 PM EST MON JAN 26 2015 IN THE WAKE OF STEADIER SNOW THAT AFFECTED KIWD THIS MORNING... EXPECT MVFR CONDITIONS TO PREVAIL THIS AFTN. ANOTHER DISTURBANCE TRACKING SSE WILL BRING A ROUND OF -SN TO KIWD/KCMX/KSAW LATE THIS AFTN/EVENING. WHILE KIWD SHOULD REMAIN MVFR AS THE -SN PASSES...STEADIER SNOW AT KCMX/KSAW WILL LIKELY DROP CONDITIONS FROM VFR TO IFR. LINGERING MOISTURE BEHIND THE DISTURBANCE WILL RESULT IN CONDITIONS FALLING TO IFR AT KIWD BY LATE EVENING. IFR/LOW MVFR CIGS WILL LIKELY PERSIST AT ALL TERMINALS THRU TUE MORNING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 434 PM EST MON JAN 26 2015 WITH WEAK LOW PRES OVER NE MN DROPPING SSE TONIGHT...STRONGER S WINDS OF 20-30KT WILL CONTINUE OVER ERN LAKE SUEPRIOR THRU THIS EVENING BEFORE DIMINISHING OVERNIGHT. WITH WEAKER PRES GRADIENT OVER THE W...WINDS WILL BE UNDER 20KT. WINDS WILL THEN BE UNDER 20KT ACROSS THE ENTIRE LAKE TUE/WED AS HIGH PRES RIDGE DRIFTS SSE FROM THE UPPER LAKES. LOW PRES WILL THEN TRACK FROM THE MID MISSISSIPPI VALLEY WED NIGHT TO THE LOWER LAKES THU NIGHT. BEHIND THE LOW...N TO NW WINDS WILL INCREASE TO 20-30KT THU/THU NIGHT WITH GALES POSSIBLE OVER THE E HALF OF THE LAKE. WINDS WILL THEN DIMINISH FRI AS HIGH PRES PASSES ACROSS THE WRN GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1249 PM EST MON JAN 26 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 416 AM EST MON JAN 26 2015 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT OVER CENTRAL NAMERICA BTWN A HI AMPLITUDE RDG OVER THE W AND A DEEP TROF OVER THE E. THERE ARE 2 SHRTWVS OF INTEREST EMBEDDED IN THE NW FLOW...THE FIRST IS DIGGING SEWD INTO NW MN WHILE ANOTHER IS MOVING SEWD THRU NRN MANITOBA/FAR NW ONTARIO. A FAIRLY VIGOROUS 998MB LO OVER CENTRAL MANITOBA IS THE SFC REFLECTION OF THESE DISTURBANCES. UPR MI IS UNDER THE SSW FLOW BTWN THIS LO AND SLOWLY RETREATING ARCTIC HI PRES NEAR THE ONTARIO/QUEBEC BORDER. THE PRES GRADIENT IS MUCH TIGHTER OVER MN CLOSER TO THE LO...AND SOME LIGHT SN IS NOTED ON THE SFC OBS/RADAR COMPOSITES MOVING THRU NRN MN. ALTHOUGH NEARBY RAOBS SHOW SOME MID LVL MSTR WITH 00Z H7 DEWPT DEPRESSIONS OF ONLY 2C AND 4C AT YPL AND INL RESPECTIVELY...THE RAOBS ALSO INDICATE SOME LLVL DRY AIR LINGERS ACROSS THE AREA...WITH 00Z H85 DEWPT DEPRESSIONS OF 26C AT MPX...22C AT GRB AND EVEN 13C AT INL/10C AT YPL CLOSER TO THE SFC LO. SO THE OBSVD SN INTENSITY AND COVERAGE IS NOT THAT GREAT DESPITE SOME FAIRLY STRONG ISENTROPIC ASCENT NOTED ON THE 290K SFC /ABOUT H7/. MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS/SN AMOUNTS ASSOCIATED WITH THE 2 SHRTWVS NOTED ABOVE. SINCE THERE ARE 2 DISTURBANCES/SEPARATE AREAS OF DEEP LYR FORCING...THE INITIAL SHRTWV IS TENDING TO TRACK FARTHER W DUE TO THE HI AMPLITUDE PATTERN AND LARGER SCALE MSTR INFLOW WL REMAIN FAIRLY LIMITED...EXPECT SN AMOUNTS TO BE SUB ADVY. SHRTWV NOW MOVING INTO NW MN IS PROGGED TO DIG SSEWD THIS MRNG... WITH AREA OF DEEP LYR QVECTOR CNVGC/SHARPER ISENTROPIC ASCENT ON THE 290K SFC IMPACTING MAINLY JUST THE WRN CWA THIS MRNG. THE SECOND SHRTWV WL REACH FAR NW LK SUP LATE THIS AFTN...WITH AREA OF DPVA/DEEP LYR QVECTOR CNVGC BUT WEAKER ISENTROPIC ASCENT INFLUENCING MUCH OF THE CWA THIS AFTN/EVNG BEFORE FADING OVERNGT WITH APRCH OF TRAILING SHRTWV RDG AXIS AND DNVA/DEEP LYR QVECTOR DVGC. WHILE THE EXPECTED FORCING MAY JUSTIFY LIKELY TO CATEGORICAL POPS UNDER THE BETTER FORCING...LIMITED MSTR INFLOW WL BE A MAJOR LIMITING FACTOR. IN FACT THE H7 SPECIFIC HUMIDITY FCST UP TO 2 G/KG OVER THE W THIS MRNG INTO EARLY AFTN IS FCST TO DIMINISH DURING THE EVENT. SO DESPITE A FAVORABLE DEPTH/LOCATION OF THE DGZ CENTERED ARND 10K FT...EXPECT SN TOTALS NOT MORE THAN 1 TO PERHAPS 3 INCHES... HEAVIEST OVER THE W HALF BECAUSE THESE AREAS WL BE IMPACTED BY BOTH SHRTWVS. SINCE SLOWLY BACKING LLVL FLOW WL ATTEMPT TO MAINTAIN FEED OF NEAR SFC DRY AIR INTO THE E...FCST LOWER POPS/SN AMOUNTS IN THAT AREA. IN FACT...THE FAR E MAY SEE LITTLE SN THRU TNGT. ONE CONCERN FOR HEAVIER SN WL BE OVER THE SCENTRAL LATER THIS AFTN/EVNG DOWWIND OF LK MI IN THE LLVL SLY FLOW AND WHEN DEEPER MSTR/FORCING ASSOCIATED WITH 2ND SHRTWV WL ARRIVE IN THE PRESENCE OF H85 TEMPS /- 10 TO -12C/ SUFFICIENTLY COLD FOR SOME LK ENHANCEMENT. HOWEVER...FAIRLY SHARP DIRECTIONAL SHEAR WITH BACKING LLVL SE FLOW TURNING TO THE SSW AT H85 AND MAINTAINING A FEED OF NEAR SFC DRY AIR MAY OFFSET THIS POTENTIAL. BUT OPTED TO MAINTAIN SOME HIER CATEGORICAL POPS/QPF CENTERED NEAR ESCANABA TO ACCOUNT FOR THE POTENTIAL LK ENHANCEMENT. TEMPS TODAY SHOULD RECOVER INTO THE 20S OVER MOST OF THE CWA EXCEPT OVER THE E...CLOSER TO SLOWLY RETREATING HI PRES/CORE OF COLDER AIR AND WHERE H85 TEMPS ARE FCST TO RISE NO HIER THAN -12 TO -13C. LINGERING CLDS THRU TNGT WL GREATLY LIMIT THE DIURNAL TEMP FALL. THE COLDEST TEMPS AOB 10F WL ONCE AGAIN OCCUR OVER THE E. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 105 AM EST MON JAN 26 2015 WITH THE 500MB LOW AND THE AXIS OF THE 500MB TROUGH SHIFTED OVER THE NEW ENGLAND STATES TUESDAY...THE RIDGE CURRENTLY OVER THE W HALF OF THE NATION WILL BE ABLE TO SHIFT ACROSS THE CENTRAL PLAINS AND UPPER GREAT LAKES TUESDAY INTO EARLY WEDNESDAY. AT THE SFC...A RIDGE WILL BE ABLE TO SLIDE ACROSS LAKE SUPERIOR TUESDAY /EXTENDING FROM MN UP THROUGH NEWFOUNDLAND/...WHICH WILL LINGER INTO TUESDAY NIGHT AS THE MAIN AREA OF HIGH PRESSURE PUSHES INTO THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE RESULT WILL BE A DRY PERIOD AT LEAST UNTIL MID DAY WEDNESDAY...ALTHOUGH THERE MAY STILL BE SOME CLOUDS LINGERING/STUCK BELOW THE 850-900MB SUBSIDENCE INVERSION. TRICKY CLOUD COVER FCST FOR THIS PERIOD. WEDNESDAY LOOK TO BE THE LAST WARM DAY IN A WHILE...WITH TEMPERATURES NEAR FREEZING. 850MB TEMPS ON S FLOW WILL RISE TO -1 TO -4C THROUGH THE DAYTIME HOURS AS THICKER CLOUDS INVADE FROM THE NW. AN ELONGATED AREA OF LOW PRESSURE OVER THE N AND CENTRAL PLAINS WEDNESDAY MORNING WILL EDGE E ACROSS IL AND IN THURSDAY MORNING...AND OFF TO THE LOWER GREAT LAKES AND OFF THE MID ATLANTIC STATES FRIDAY. THIS WILL BRING A TROUGH ACROSS OUR AREA WEDNESDAY NIGHT THROUGH THURSDAY EVENING...WHICH WILL BE ENHANCED BY THE SUPPRESSION OF THE 500MB RIDGE WEDNESDAY EVENING AND THURSDAY. LOOK FOR A WIDESPREAD 2-5IN OF SNOW WITH SLR VALUES AROUND 15:1. EXPECT THE HIGHER VALUES OVER THE N HALF OF UPPER MI AS IT WILL LIKELY TAKE UNTIL LATE AFTERNOON/EARLY EVENING FOR SNOW TO BEGIN S CENTRAL. WILL NOT GO QUITE AS QUICK WITH THE INVADING PRECIP AS THE 00Z NAM...BUT A BLENDED SOLUTION SOUNDS REASONABLE. A WINTER WX ADVISORY MAY BE NEEDED IF THE 2-5IN CAN FALL IN A 12HR PERIOD. WILL CONTINUE TO LOOK INTO THIS FOR POSSIBLE POSTING OF HEADLINES ON TUESDAY...AND HIGHLIGHT THE POTENTIAL FOR LIGHT TO MODERATE SNOW IN THE HWO. N FLOW BEHIND THE EXITING SFC TROUGH THURSDAY AFTERNOON WILL BE THE START OF OUR COOL DOWN...WITH 850MB TEMPS FALLING TO -8 TO -10C. WHILE NOT QUITE OPTIMAL FOR LAKE EFFECT YET...SOME LAKE ENHANCEMENT WILL BE LIKELY ALONG THE UPSLOPE N SNOWBELTS ALONG LAKE SUPERIOR THURSDAY AS THE SFC LOW EXITS TO THE LOWER GREAT LAKES/PENNSYLVANIA FRIDAY EVENING. DESPITE SFC-500MB RIDGING ON FRIDAY...A FEW LINGERING LES WILL REMAIN ALONG THE LAKE SUPERIOR SHORELINES. DON/T EXPECT MUCH IN THE WAY OF ACCUMULATIONS AS THE MOISTURE IS AGAIN TRAPPED BELOW 850MB. BUT WILL THE MOISTURE LAYER IN THE DGZ /850MB TEMPS OF -15 TO -17C/...SOME LIGHT ACCUMULATIONS WILL BE POSSIBLE. SLIGHTLY WARMER AIR WILL PUSH IN THROUGH EARLY SATURDAY MORNING AS THE SFC RIDGE EXITS TO THE LOWER GREAT LAKES...AND IN ADVANCE OF LOW PRESSURE DEVELOPING NEARING FROM THE N PLAINS STATES. SOME OF THE COLDEST AIR OF THE SEASON WILL PUSH INTO THE UPPER GREAT LAKES SATURDAY AFTERNOON ON. THERE CONTINUES TO BE SOME TIMING ISSUES ON THE ORDER OF AROUND 6HRS...WHICH IS PRETTY MINOR THIS FAR OUT IN THE FCST...AND A BLENDED SOLUTION LOOKS REASONABLE. 850MB TEMPS OF -20 TO -30C WILL SETTLE IN SUNDAY AFTERNOON AS THE SFC LOW EXITS AND THE MAIN 500MB TROUGH PUSHES ACROSS THE UPPER GREAT LAKES. LOOK FOR FINE LES THAT WILL BE GOOD AT REDUCING VIS...ESPECIALLY IF THE STRONGER NW WINDS OF THE 25/12Z ECMWF ARE CORRECT/. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1249 PM EST MON JAN 26 2015 IN THE WAKE OF STEADIER SNOW THAT AFFECTED KIWD THIS MORNING... EXPECT MVFR CONDITIONS TO PREVAIL THIS AFTN. ANOTHER DISTURBANCE TRACKING SSE WILL BRING A ROUND OF -SN TO KIWD/KCMX/KSAW LATE THIS AFTN/EVENING. WHILE KIWD SHOULD REMAIN MVFR AS THE -SN PASSES...STEADIER SNOW AT KCMX/KSAW WILL LIKELY DROP CONDITIONS FROM VFR TO IFR. LINGERING MOISTURE BEHIND THE DISTURBANCE WILL RESULT IN CONDITIONS FALLING TO IFR AT KIWD BY LATE EVENING. IFR/LOW MVFR CIGS WILL LIKELY PERSIST AT ALL TERMINALS THRU TUE MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 AM EST MON JAN 26 2015 EXPECT S WINDS UP TO 20-25 KTS OVER MUCH OF LAKE SUPERIOR INTO THIS AFTERNOON AS THE PRES GRADIENT TIGHTENS BETWEEN HI PRES DEPARTING TO THE E AND A LO PRES MOVING SOUTHEAST TOWARD WESTERN LAKE SUPERIOR. WINDS WILL DIMINISH LATER THIS AFTERNOON AND TONIGHT AS THE LO WEAKENS AND SLIDES TO THE S. THEN RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PREVAIL THRU WED AS A HI PRES RIDGE AND RATHER SLACK PRES GRADIENT DOMINATES THE AREA. LOOK FOR STRONGER N WINDS UP TO 25 KTS TO RETURN ON THU AS A LO PRES MOVES E THROUGH THE LOWER GREAT LAKES AHEAD OF HI PRES BUILDING THROUGH CENTRAL CANADA...TIGHTENING THE PRES GRADIENT AGAIN OVER LAKE SUPERIOR. THE INFLUX OF COLDER AIR AND WAVES BUILT UP BY THE GUSTY WINDS WILL LIKELY BRING A RETURN OF FREEZING SPRAY TO AT LEAST PORTIONS OF THE LAKE. THE CLOSER APPROACH OF THE HI ON FRI WILL BRING A RETURN OF MORE TRANQUIL CONDITIONS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
637 AM EST MON JAN 26 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 416 AM EST MON JAN 26 2015 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT OVER CENTRAL NAMERICA BTWN A HI AMPLITUDE RDG OVER THE W AND A DEEP TROF OVER THE E. THERE ARE 2 SHRTWVS OF INTEREST EMBEDDED IN THE NW FLOW...THE FIRST IS DIGGING SEWD INTO NW MN WHILE ANOTHER IS MOVING SEWD THRU NRN MANITOBA/FAR NW ONTARIO. A FAIRLY VIGOROUS 998MB LO OVER CENTRAL MANITOBA IS THE SFC REFLECTION OF THESE DISTURBANCES. UPR MI IS UNDER THE SSW FLOW BTWN THIS LO AND SLOWLY RETREATING ARCTIC HI PRES NEAR THE ONTARIO/QUEBEC BORDER. THE PRES GRADIENT IS MUCH TIGHTER OVER MN CLOSER TO THE LO...AND SOME LIGHT SN IS NOTED ON THE SFC OBS/RADAR COMPOSITES MOVING THRU NRN MN. ALTHOUGH NEARBY RAOBS SHOW SOME MID LVL MSTR WITH 00Z H7 DEWPT DEPRESSIONS OF ONLY 2C AND 4C AT YPL AND INL RESPECTIVELY...THE RAOBS ALSO INDICATE SOME LLVL DRY AIR LINGERS ACROSS THE AREA...WITH 00Z H85 DEWPT DEPRESSIONS OF 26C AT MPX...22C AT GRB AND EVEN 13C AT INL/10C AT YPL CLOSER TO THE SFC LO. SO THE OBSVD SN INTENSITY AND COVERAGE IS NOT THAT GREAT DESPITE SOME FAIRLY STRONG ISENTROPIC ASCENT NOTED ON THE 290K SFC /ABOUT H7/. MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS/SN AMOUNTS ASSOCIATED WITH THE 2 SHRTWVS NOTED ABOVE. SINCE THERE ARE 2 DISTURBANCES/SEPARATE AREAS OF DEEP LYR FORCING...THE INITIAL SHRTWV IS TENDING TO TRACK FARTHER W DUE TO THE HI AMPLITUDE PATTERN AND LARGER SCALE MSTR INFLOW WL REMAIN FAIRLY LIMITED...EXPECT SN AMOUNTS TO BE SUB ADVY. SHRTWV NOW MOVING INTO NW MN IS PROGGED TO DIG SSEWD THIS MRNG... WITH AREA OF DEEP LYR QVECTOR CNVGC/SHARPER ISENTROPIC ASCENT ON THE 290K SFC IMPACTING MAINLY JUST THE WRN CWA THIS MRNG. THE SECOND SHRTWV WL REACH FAR NW LK SUP LATE THIS AFTN...WITH AREA OF DPVA/DEEP LYR QVECTOR CNVGC BUT WEAKER ISENTROPIC ASCENT INFLUENCING MUCH OF THE CWA THIS AFTN/EVNG BEFORE FADING OVERNGT WITH APRCH OF TRAILING SHRTWV RDG AXIS AND DNVA/DEEP LYR QVECTOR DVGC. WHILE THE EXPECTED FORCING MAY JUSTIFY LIKELY TO CATEGORICAL POPS UNDER THE BETTER FORCING...LIMITED MSTR INFLOW WL BE A MAJOR LIMITING FACTOR. IN FACT THE H7 SPECIFIC HUMIDITY FCST UP TO 2 G/KG OVER THE W THIS MRNG INTO EARLY AFTN IS FCST TO DIMINISH DURING THE EVENT. SO DESPITE A FAVORABLE DEPTH/LOCATION OF THE DGZ CENTERED ARND 10K FT...EXPECT SN TOTALS NOT MORE THAN 1 TO PERHAPS 3 INCHES... HEAVIEST OVER THE W HALF BECAUSE THESE AREAS WL BE IMPACTED BY BOTH SHRTWVS. SINCE SLOWLY BACKING LLVL FLOW WL ATTEMPT TO MAINTAIN FEED OF NEAR SFC DRY AIR INTO THE E...FCST LOWER POPS/SN AMOUNTS IN THAT AREA. IN FACT...THE FAR E MAY SEE LITTLE SN THRU TNGT. ONE CONCERN FOR HEAVIER SN WL BE OVER THE SCENTRAL LATER THIS AFTN/EVNG DOWWIND OF LK MI IN THE LLVL SLY FLOW AND WHEN DEEPER MSTR/FORCING ASSOCIATED WITH 2ND SHRTWV WL ARRIVE IN THE PRESENCE OF H85 TEMPS /- 10 TO -12C/ SUFFICIENTLY COLD FOR SOME LK ENHANCEMENT. HOWEVER...FAIRLY SHARP DIRECTIONAL SHEAR WITH BACKING LLVL SE FLOW TURNING TO THE SSW AT H85 AND MAINTAINING A FEED OF NEAR SFC DRY AIR MAY OFFSET THIS POTENTIAL. BUT OPTED TO MAINTAIN SOME HIER CATEGORICAL POPS/QPF CENTERED NEAR ESCANABA TO ACCOUNT FOR THE POTENTIAL LK ENHANCEMENT. TEMPS TODAY SHOULD RECOVER INTO THE 20S OVER MOST OF THE CWA EXCEPT OVER THE E...CLOSER TO SLOWLY RETREATING HI PRES/CORE OF COLDER AIR AND WHERE H85 TEMPS ARE FCST TO RISE NO HIER THAN -12 TO -13C. LINGERING CLDS THRU TNGT WL GREATLY LIMIT THE DIURNAL TEMP FALL. THE COLDEST TEMPS AOB 10F WL ONCE AGAIN OCCUR OVER THE E. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 105 AM EST MON JAN 26 2015 WITH THE 500MB LOW AND THE AXIS OF THE 500MB TROUGH SHIFTED OVER THE NEW ENGLAND STATES TUESDAY...THE RIDGE CURRENTLY OVER THE W HALF OF THE NATION WILL BE ABLE TO SHIFT ACROSS THE CENTRAL PLAINS AND UPPER GREAT LAKES TUESDAY INTO EARLY WEDNESDAY. AT THE SFC...A RIDGE WILL BE ABLE TO SLIDE ACROSS LAKE SUPERIOR TUESDAY /EXTENDING FROM MN UP THROUGH NEWFOUNDLAND/...WHICH WILL LINGER INTO TUESDAY NIGHT AS THE MAIN AREA OF HIGH PRESSURE PUSHES INTO THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE RESULT WILL BE A DRY PERIOD AT LEAST UNTIL MID DAY WEDNESDAY...ALTHOUGH THERE MAY STILL BE SOME CLOUDS LINGERING/STUCK BELOW THE 850-900MB SUBSIDENCE INVERSION. TRICKY CLOUD COVER FCST FOR THIS PERIOD. WEDNESDAY LOOK TO BE THE LAST WARM DAY IN A WHILE...WITH TEMPERATURES NEAR FREEZING. 850MB TEMPS ON S FLOW WILL RISE TO -1 TO -4C THROUGH THE DAYTIME HOURS AS THICKER CLOUDS INVADE FROM THE NW. AN ELONGATED AREA OF LOW PRESSURE OVER THE N AND CENTRAL PLAINS WEDNESDAY MORNING WILL EDGE E ACROSS IL AND IN THURSDAY MORNING...AND OFF TO THE LOWER GREAT LAKES AND OFF THE MID ATLANTIC STATES FRIDAY. THIS WILL BRING A TROUGH ACROSS OUR AREA WEDNESDAY NIGHT THROUGH THURSDAY EVENING...WHICH WILL BE ENHANCED BY THE SUPPRESSION OF THE 500MB RIDGE WEDNESDAY EVENING AND THURSDAY. LOOK FOR A WIDESPREAD 2-5IN OF SNOW WITH SLR VALUES AROUND 15:1. EXPECT THE HIGHER VALUES OVER THE N HALF OF UPPER MI AS IT WILL LIKELY TAKE UNTIL LATE AFTERNOON/EARLY EVENING FOR SNOW TO BEGIN S CENTRAL. WILL NOT GO QUITE AS QUICK WITH THE INVADING PRECIP AS THE 00Z NAM...BUT A BLENDED SOLUTION SOUNDS REASONABLE. A WINTER WX ADVISORY MAY BE NEEDED IF THE 2-5IN CAN FALL IN A 12HR PERIOD. WILL CONTINUE TO LOOK INTO THIS FOR POSSIBLE POSTING OF HEADLINES ON TUESDAY...AND HIGHLIGHT THE POTENTIAL FOR LIGHT TO MODERATE SNOW IN THE HWO. N FLOW BEHIND THE EXITING SFC TROUGH THURSDAY AFTERNOON WILL BE THE START OF OUR COOL DOWN...WITH 850MB TEMPS FALLING TO -8 TO -10C. WHILE NOT QUITE OPTIMAL FOR LAKE EFFECT YET...SOME LAKE ENHANCEMENT WILL BE LIKELY ALONG THE UPSLOPE N SNOWBELTS ALONG LAKE SUPERIOR THURSDAY AS THE SFC LOW EXITS TO THE LOWER GREAT LAKES/PENNSYLVANIA FRIDAY EVENING. DESPITE SFC-500MB RIDGING ON FRIDAY...A FEW LINGERING LES WILL REMAIN ALONG THE LAKE SUPERIOR SHORELINES. DON/T EXPECT MUCH IN THE WAY OF ACCUMULATIONS AS THE MOISTURE IS AGAIN TRAPPED BELOW 850MB. BUT WILL THE MOISTURE LAYER IN THE DGZ /850MB TEMPS OF -15 TO -17C/...SOME LIGHT ACCUMULATIONS WILL BE POSSIBLE. SLIGHTLY WARMER AIR WILL PUSH IN THROUGH EARLY SATURDAY MORNING AS THE SFC RIDGE EXITS TO THE LOWER GREAT LAKES...AND IN ADVANCE OF LOW PRESSURE DEVELOPING NEARING FROM THE N PLAINS STATES. SOME OF THE COLDEST AIR OF THE SEASON WILL PUSH INTO THE UPPER GREAT LAKES SATURDAY AFTERNOON ON. THERE CONTINUES TO BE SOME TIMING ISSUES ON THE ORDER OF AROUND 6HRS...WHICH IS PRETTY MINOR THIS FAR OUT IN THE FCST...AND A BLENDED SOLUTION LOOKS REASONABLE. 850MB TEMPS OF -20 TO -30C WILL SETTLE IN SUNDAY AFTERNOON AS THE SFC LOW EXITS AND THE MAIN 500MB TROUGH PUSHES ACROSS THE UPPER GREAT LAKES. LOOK FOR FINE LES THAT WILL BE GOOD AT REDUCING VIS...ESPECIALLY IF THE STRONGER NW WINDS OF THE 25/12Z ECMWF ARE CORRECT/. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 636 AM EST MON JAN 26 2015 SOME -SN ASSOCIATED WITH A CLIPPER TYPE LO MOVING FM NRN MN SSE INTO WI TNGT WL IMPACT THE TAF SITES THIS FCST PERIOD. STEADIER SN WL FALL AT IWD THIS MRNG...REDUCING VSBY INTO THE IFR RANGE UNTIL THE SN SHIFTS AWAY THIS AFTN AND CONDITIONS REBOUND TO MVFR. AS THE AREA OF SN DRIFTS ONLY SLOWLY TO THE E INTO FAIRLY DRY LLVL AIR ASSOCIATED WITH DEPARTING HI PRES IN SE CANADA...EXPECT VFR CONDITIONS AT CMX AND SAW TO DETERIORATE TO MVFR AND THEN IFR BY LATE THIS AFTN. ALTHOUGH THE STEADIER SN WL EXIT THE AREA TNGT...LINGERING LLVL MSTR WL RESULT IN LO END MVFR/HI IFR CONDITIONS. THE LOCATION MOST LIKELY TO SEE IFR CONDITIONS WL BE SAW WITH AN UPSLOPE SE WIND OFF LK MI. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 AM EST MON JAN 26 2015 EXPECT S WINDS UP TO 20-25 KTS OVER MUCH OF LAKE SUPERIOR INTO THIS AFTERNOON AS THE PRES GRADIENT TIGHTENS BETWEEN HI PRES DEPARTING TO THE E AND A LO PRES MOVING SOUTHEAST TOWARD WESTERN LAKE SUPERIOR. WINDS WILL DIMINISH LATER THIS AFTERNOON AND TONIGHT AS THE LO WEAKENS AND SLIDES TO THE S. THEN RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PREVAIL THRU WED AS A HI PRES RIDGE AND RATHER SLACK PRES GRADIENT DOMINATES THE AREA. LOOK FOR STRONGER N WINDS UP TO 25 KTS TO RETURN ON THU AS A LO PRES MOVES E THROUGH THE LOWER GREAT LAKES AHEAD OF HI PRES BUILDING THROUGH CENTRAL CANADA...TIGHTENING THE PRES GRADIENT AGAIN OVER LAKE SUPERIOR. THE INFLUX OF COLDER AIR AND WAVES BUILT UP BY THE GUSTY WINDS WILL LIKELY BRING A RETURN OF FREEZING SPRAY TO AT LEAST PORTIONS OF THE LAKE. THE CLOSER APPROACH OF THE HI ON FRI WILL BRING A RETURN OF MORE TRANQUIL CONDITIONS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
416 AM EST MON JAN 26 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 416 AM EST MON JAN 26 2015 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A NW FLOW ALOFT OVER CENTRAL NAMERICA BTWN A HI AMPLITUDE RDG OVER THE W AND A DEEP TROF OVER THE E. THERE ARE 2 SHRTWVS OF INTEREST EMBEDDED IN THE NW FLOW...THE FIRST IS DIGGING SEWD INTO NW MN WHILE ANOTHER IS MOVING SEWD THRU NRN MANITOBA/FAR NW ONTARIO. A FAIRLY VIGOROUS 998MB LO OVER CENTRAL MANITOBA IS THE SFC REFLECTION OF THESE DISTURBANCES. UPR MI IS UNDER THE SSW FLOW BTWN THIS LO AND SLOWLY RETREATING ARCTIC HI PRES NEAR THE ONTARIO/QUEBEC BORDER. THE PRES GRADIENT IS MUCH TIGHTER OVER MN CLOSER TO THE LO...AND SOME LIGHT SN IS NOTED ON THE SFC OBS/RADAR COMPOSITES MOVING THRU NRN MN. ALTHOUGH NEARBY RAOBS SHOW SOME MID LVL MSTR WITH 00Z H7 DEWPT DEPRESSIONS OF ONLY 2C AND 4C AT YPL AND INL RESPECTIVELY...THE RAOBS ALSO INDICATE SOME LLVL DRY AIR LINGERS ACROSS THE AREA...WITH 00Z H85 DEWPT DEPRESSIONS OF 26C AT MPX...22C AT GRB AND EVEN 13C AT INL/10C AT YPL CLOSER TO THE SFC LO. SO THE OBSVD SN INTENSITY AND COVERAGE IS NOT THAT GREAT DESPITE SOME FAIRLY STRONG ISENTROPIC ASCENT NOTED ON THE 290K SFC /ABOUT H7/. MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON POPS/SN AMOUNTS ASSOCIATED WITH THE 2 SHRTWVS NOTED ABOVE. SINCE THERE ARE 2 DISTURBANCES/SEPARATE AREAS OF DEEP LYR FORCING...THE INITIAL SHRTWV IS TENDING TO TRACK FARTHER W DUE TO THE HI AMPLITUDE PATTERN AND LARGER SCALE MSTR INFLOW WL REMAIN FAIRLY LIMITED...EXPECT SN AMOUNTS TO BE SUB ADVY. SHRTWV NOW MOVING INTO NW MN IS PROGGED TO DIG SSEWD THIS MRNG... WITH AREA OF DEEP LYR QVECTOR CNVGC/SHARPER ISENTROPIC ASCENT ON THE 290K SFC IMPACTING MAINLY JUST THE WRN CWA THIS MRNG. THE SECOND SHRTWV WL REACH FAR NW LK SUP LATE THIS AFTN...WITH AREA OF DPVA/DEEP LYR QVECTOR CNVGC BUT WEAKER ISENTROPIC ASCENT INFLUENCING MUCH OF THE CWA THIS AFTN/EVNG BEFORE FADING OVERNGT WITH APRCH OF TRAILING SHRTWV RDG AXIS AND DNVA/DEEP LYR QVECTOR DVGC. WHILE THE EXPECTED FORCING MAY JUSTIFY LIKELY TO CATEGORICAL POPS UNDER THE BETTER FORCING...LIMITED MSTR INFLOW WL BE A MAJOR LIMITING FACTOR. IN FACT THE H7 SPECIFIC HUMIDITY FCST UP TO 2 G/KG OVER THE W THIS MRNG INTO EARLY AFTN IS FCST TO DIMINISH DURING THE EVENT. SO DESPITE A FAVORABLE DEPTH/LOCATION OF THE DGZ CENTERED ARND 10K FT...EXPECT SN TOTALS NOT MORE THAN 1 TO PERHAPS 3 INCHES... HEAVIEST OVER THE W HALF BECAUSE THESE AREAS WL BE IMPACTED BY BOTH SHRTWVS. SINCE SLOWLY BACKING LLVL FLOW WL ATTEMPT TO MAINTAIN FEED OF NEAR SFC DRY AIR INTO THE E...FCST LOWER POPS/SN AMOUNTS IN THAT AREA. IN FACT...THE FAR E MAY SEE LITTLE SN THRU TNGT. ONE CONCERN FOR HEAVIER SN WL BE OVER THE SCENTRAL LATER THIS AFTN/EVNG DOWWIND OF LK MI IN THE LLVL SLY FLOW AND WHEN DEEPER MSTR/FORCING ASSOCIATED WITH 2ND SHRTWV WL ARRIVE IN THE PRESENCE OF H85 TEMPS /- 10 TO -12C/ SUFFICIENTLY COLD FOR SOME LK ENHANCEMENT. HOWEVER...FAIRLY SHARP DIRECTIONAL SHEAR WITH BACKING LLVL SE FLOW TURNING TO THE SSW AT H85 AND MAINTAINING A FEED OF NEAR SFC DRY AIR MAY OFFSET THIS POTENTIAL. BUT OPTED TO MAINTAIN SOME HIER CATEGORICAL POPS/QPF CENTERED NEAR ESCANABA TO ACCOUNT FOR THE POTENTIAL LK ENHANCEMENT. TEMPS TODAY SHOULD RECOVER INTO THE 20S OVER MOST OF THE CWA EXCEPT OVER THE E...CLOSER TO SLOWLY RETREATING HI PRES/CORE OF COLDER AIR AND WHERE H85 TEMPS ARE FCST TO RISE NO HIER THAN -12 TO -13C. LINGERING CLDS THRU TNGT WL GREATLY LIMIT THE DIURNAL TEMP FALL. THE COLDEST TEMPS AOB 10F WL ONCE AGAIN OCCUR OVER THE E. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 105 AM EST MON JAN 26 2015 WITH THE 500MB LOW AND THE AXIS OF THE 500MB TROUGH SHIFTED OVER THE NEW ENGLAND STATES TUESDAY...THE RIDGE CURRENTLY OVER THE W HALF OF THE NATION WILL BE ABLE TO SHIFT ACROSS THE CENTRAL PLAINS AND UPPER GREAT LAKES TUESDAY INTO EARLY WEDNESDAY. AT THE SFC...A RIDGE WILL BE ABLE TO SLIDE ACROSS LAKE SUPERIOR TUESDAY /EXTENDING FROM MN UP THROUGH NEWFOUNDLAND/...WHICH WILL LINGER INTO TUESDAY NIGHT AS THE MAIN AREA OF HIGH PRESSURE PUSHES INTO THE OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE RESULT WILL BE A DRY PERIOD AT LEAST UNTIL MID DAY WEDNESDAY...ALTHOUGH THERE MAY STILL BE SOME CLOUDS LINGERING/STUCK BELOW THE 850-900MB SUBSIDENCE INVERSION. TRICKY CLOUD COVER FCST FOR THIS PERIOD. WEDNESDAY LOOK TO BE THE LAST WARM DAY IN A WHILE...WITH TEMPERATURES NEAR FREEZING. 850MB TEMPS ON S FLOW WILL RISE TO -1 TO -4C THROUGH THE DAYTIME HOURS AS THICKER CLOUDS INVADE FROM THE NW. AN ELONGATED AREA OF LOW PRESSURE OVER THE N AND CENTRAL PLAINS WEDNESDAY MORNING WILL EDGE E ACROSS IL AND IN THURSDAY MORNING...AND OFF TO THE LOWER GREAT LAKES AND OFF THE MID ATLANTIC STATES FRIDAY. THIS WILL BRING A TROUGH ACROSS OUR AREA WEDNESDAY NIGHT THROUGH THURSDAY EVENING...WHICH WILL BE ENHANCED BY THE SUPPRESSION OF THE 500MB RIDGE WEDNESDAY EVENING AND THURSDAY. LOOK FOR A WIDESPREAD 2-5IN OF SNOW WITH SLR VALUES AROUND 15:1. EXPECT THE HIGHER VALUES OVER THE N HALF OF UPPER MI AS IT WILL LIKELY TAKE UNTIL LATE AFTERNOON/EARLY EVENING FOR SNOW TO BEGIN S CENTRAL. WILL NOT GO QUITE AS QUICK WITH THE INVADING PRECIP AS THE 00Z NAM...BUT A BLENDED SOLUTION SOUNDS REASONABLE. A WINTER WX ADVISORY MAY BE NEEDED IF THE 2-5IN CAN FALL IN A 12HR PERIOD. WILL CONTINUE TO LOOK INTO THIS FOR POSSIBLE POSTING OF HEADLINES ON TUESDAY...AND HIGHLIGHT THE POTENTIAL FOR LIGHT TO MODERATE SNOW IN THE HWO. N FLOW BEHIND THE EXITING SFC TROUGH THURSDAY AFTERNOON WILL BE THE START OF OUR COOL DOWN...WITH 850MB TEMPS FALLING TO -8 TO -10C. WHILE NOT QUITE OPTIMAL FOR LAKE EFFECT YET...SOME LAKE ENHANCEMENT WILL BE LIKELY ALONG THE UPSLOPE N SNOWBELTS ALONG LAKE SUPERIOR THURSDAY AS THE SFC LOW EXITS TO THE LOWER GREAT LAKES/PENNSYLVANIA FRIDAY EVENING. DESPITE SFC-500MB RIDGING ON FRIDAY...A FEW LINGERING LES WILL REMAIN ALONG THE LAKE SUPERIOR SHORELINES. DON/T EXPECT MUCH IN THE WAY OF ACCUMULATIONS AS THE MOISTURE IS AGAIN TRAPPED BELOW 850MB. BUT WILL THE MOISTURE LAYER IN THE DGZ /850MB TEMPS OF -15 TO -17C/...SOME LIGHT ACCUMULATIONS WILL BE POSSIBLE. SLIGHTLY WARMER AIR WILL PUSH IN THROUGH EARLY SATURDAY MORNING AS THE SFC RIDGE EXITS TO THE LOWER GREAT LAKES...AND IN ADVANCE OF LOW PRESSURE DEVELOPING NEARING FROM THE N PLAINS STATES. SOME OF THE COLDEST AIR OF THE SEASON WILL PUSH INTO THE UPPER GREAT LAKES SATURDAY AFTERNOON ON. THERE CONTINUES TO BE SOME TIMING ISSUES ON THE ORDER OF AROUND 6HRS...WHICH IS PRETTY MINOR THIS FAR OUT IN THE FCST...AND A BLENDED SOLUTION LOOKS REASONABLE. 850MB TEMPS OF -20 TO -30C WILL SETTLE IN SUNDAY AFTERNOON AS THE SFC LOW EXITS AND THE MAIN 500MB TROUGH PUSHES ACROSS THE UPPER GREAT LAKES. LOOK FOR FINE LES THAT WILL BE GOOD AT REDUCING VIS...ESPECIALLY IF THE STRONGER NW WINDS OF THE 25/12Z ECMWF ARE CORRECT/. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1227 AM EST MON JAN 26 2015 A CLIPPER SYSTEM DROPPING SE THROUGH SRN MANITOBA WILL MOVE ACROSS THE AREA OVERNIGHT INTO MONDAY. VFR CONDITIONS WILL GIVE WAY TO GRADUALLY LOWERING CEILINGS AHEAD OF THE SYSTEM AND THEN SNOW MOVING IN AT KIWD JUST AFT 12Z...AT KCMX LATE MON MORNING AND THEN AT KSAW EARLY MON AFTERNOON. EXPECT IFR VSBYS TO AFFECT KIWD FROM MON MORNING INTO EARLY AFTERNOON AND THEN IFR VBSYS WILL SPREAD INTO KCMX AND KSAW LATE MON AFTERNOON INTO MON EVENING AS MOISTURE DEEPENS OVER THE NW AND NCNTRL PORTION OF THE U.P. SOME IMPROVEMENT IN VSBY IS EXPECTED AT KIWD LATE MONDAY AS BEST MOISTURE DEPARTS AND SNOW TAPERS OFF. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 416 AM EST MON JAN 26 2015 EXPECT S WINDS UP TO 20-25 KTS OVER MUCH OF LAKE SUPERIOR INTO THIS AFTERNOON AS THE PRES GRADIENT TIGHTENS BETWEEN HI PRES DEPARTING TO THE E AND A LO PRES MOVING SOUTHEAST TOWARD WESTERN LAKE SUPERIOR. WINDS WILL DIMINISH LATER THIS AFTERNOON AND TONIGHT AS THE LO WEAKENS AND SLIDES TO THE S. THEN RELATIVELY LIGHT WINDS UNDER 20 KTS WILL PREVAIL THRU WED AS A HI PRES RIDGE AND RATHER SLACK PRES GRADIENT DOMINATES THE AREA. LOOK FOR STRONGER N WINDS UP TO 25 KTS TO RETURN ON THU AS A LO PRES MOVES E THROUGH THE LOWER GREAT LAKES AHEAD OF HI PRES BUILDING THROUGH CENTRAL CANADA...TIGHTENING THE PRES GRADIENT AGAIN OVER LAKE SUPERIOR. THE INFLUX OF COLDER AIR AND WAVES BUILT UP BY THE GUSTY WINDS WILL LIKELY BRING A RETURN OF FREEZING SPRAY TO AT LEAST PORTIONS OF THE LAKE. THE CLOSER APPROACH OF THE HI ON FRI WILL BRING A RETURN OF MORE TRANQUIL CONDITIONS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KF AVIATION...VOSS MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
345 PM CST MON JAN 26 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 343 PM CST MON JAN 26 2015 A SURFACE LOW ANALYZED BY THE RAP NEAR DULUTH THIS AFTERNOON WITH A STALLED WARM FRONT THROUGH EXTREME WESTERN WI...JUST EAST OF THE MN BORDER. TEMPERATURES WEST OF THE FRONT HAVE CLIMBED WELL INTO THE 40S ACROSS MOST OF THE REGION WITH DEW POINTS IN THE LOW TO MID 30S. THIS CAUSES SOME CONCERN FOR FOG DEVELOPMENT OVERNIGHT AS A SURFACE HIGH/RIDGE AXIS MOVES IN LATE TONIGHT AND WINDS GO NEARLY CALM. THE TRICKY PART OF THE FORECAST IS HOW FAR WEST THE CLOUD COVER WILL EXTEND TONIGHT. MODEL GUIDANCE IS QUITE SATURATED AT 925MB BUT CAN EASILY IMPACTED BY SURFACE MOISTURE. AN INVERSION WILL DEVELOP AFTER DARK AND COULD LOCK ANY LOW CLOUD COVER IN PLACE. CONFIDENCE IS LOW IN CLOUD COVER ACROSS WESTERN MN. IN WEST CENTRAL WISCONSIN...EAST OF THE FRONT...TEMPERATURES HAVE HELD STEADY IN THE MID 20S WITH -FZDZ AND -SN BEING REPORTED THROUGH MUCH OF THE DAY. VERY LIGHT AND SCATTER PRECIP WILL CONTINUE MOVING THROUGH THIS AREA ALONG THE FRONTAL BOUNDARY FOR THE NEXT FEW HOURS. OTHERWISE...COOLED TEMPS SLIGHTLY FOR TOMORROW ACROSS THE EAST GIVEN LINGERING CLOUD COVER...AND THE FACT THE SOUTHERLY WINDS ON THE BACK SIDE OF THE RIDGE DONT ARRIVE UNTIL LATE IN THE DAY. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 343 PM CST MON JAN 26 2015 A COUPLE CHANCES FOR LIGHT PRECIPITATION EXIST IN THE EXTENDED PERIOD OF THE FORECAST...WHILE THE COOLDOWN REMAINS ON TRACK FOR THE WEEKEND AND INTO EARLY NEXT WEEK. EARLY AFTERNOON WATERVAPOR IMAGERY TOGETHER WITH GFS 500MB HEIGHTS AND WINDS SHOWED A BROAD AREA OF NORTHEAST FLOW ACROSS THE CENTRAL CONUS SANDWHICHED BETWEEN THE NEGATIVELY TILTED RIDGE ALONG THE SPINE OF THE ROCKIES...AND MORE NOTABLY THE NEGATIVE TILTED UPPER LEVEL TROUGH DRIVING THE POWERFUL NOREASTER OVER THE NEW ENGLAND AREA. THIS NORTHWEST FLOW PATTERN WILL GENERALLY REMAIN IN PLACE ACROSS THE UPPER MIDWEST...WITH PERIODIC SHORTWAVES BRINGING REPEATED CHANCES FOR LIGHT PRECIP. THE FIRST WILL ARRIVE WEDNESDAY NIGHT...AND THERMAL PROFILES SHOW THE POTENTIAL FOR A WINTRY MIX OF LIGHT SNOW OR FREEZING DRIZZLE. NOTE...WEDNEDAYS HIGH TEMPERATURE WILL DEPEND HEAVILY ON CLOUD COVER...SO DID NOT WARM TEMPS SINCE MID/LOW LEVEL CLOUDS SHOULD KEEP AFTERNOON HIGHS FROM WARMING OUT OF CONTROL DESPITE THE FAVORABLE TIMING OF THE WARM AIR ALOFT. HIGH PRESSURE WILL BUILD IN THURSDAY AND FRIDAY...WITH COLD AIR ADVECTION LIMITING TEMPS TO NEAR 30 ON THURSDAY...AND 20S ON FRIDAY. FRIDAY NIGHT ANOTHER SYSTEM WILL MOVE ACROSS THE REGION...BUT STRENGTH AND TIMING REMAIN UNCERTAIN. THE GFS IS FASTER AND STRONGER THAN THE ECMWF/GEM...BUT NEITHER SOLUTION PRODUCES SIGNIFICANT PRECIP...WHICH WILL BE ALL SNOW...ACROSS THE REGION. COLD AIR WILL FUNNEL IN FOR THE EARLY PART OF NEXT WEEK...AND TO ECHO THE THOUGHTS OF THE PREVIOUS FORECASTER...IT APPEARS MONDAY WILL HAVE HIGHS IN THE SINGLE DIGITS...WITH LOWS BELOW ZERO OVERNIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1154 AM CST MON JAN 26 2015 WARM FRONTAL BOUNDARY ORIENTED N-S HAS REACHED THE MN/WI BORDER...WITH CLEAR SKIES AND WARM TEMPERATURES WEST OF IT...AND COLD TEMPS/-SN/-FZDZ EAST AND NORTH OF IT UNDER LOW STRATUS. EXPECTING THIS FRONT TO BE QUASI-STATIONARY SO LITTLE MOVEMENT IN THE STRATUS IS EXPECTED FOR THE REMAINDER OF THE DAY. WESTERN MN WILL REMAIN MOSTLY CLEAR AND EXPECT VFR FOR THE ENTIRE PERIOD. A MUCH MORE COMPLICATED SCENARIO IN EASTERN MN...NEAR THE BOUNDARY ITSELF. 925 RH FIELDS INDICATE THE POTENTIAL FOR LOW STRATUS TO GET STUCK UNDER AN INVERSION TONIGHT...AS THE CLOUD COVER IN NORTHERN MN ADVECTS SOUTHWARD THROUGH THE REMAINDER OF THE DAY. STILL...NOT CONFIDENT IN THESE HIGH RH LEVELS IN THE LOWER LEVELS ACTUALLY TRANSLATING TO LOW CIGS. SIGNIFICANT DRYING JUST ABOVE THIS LEVEL /AND THE INVERSION/ MAKES IT A TOUGH CALL FROM LATE TONIGHT THROUGH TUESDAY MORNING. LEANED TO THE OPTIMISTIC SIDE AND SCATTERED OUT THE LOW CEILINGS LATE TONIGHT...BUT BE AWARE THERE IS POTENTIAL THE LOW CIGS COULD STICK AROUND ALL NIGHT. KMSP...VFR INITIALLY AS WE LINGER NEAR THE EDGE OF THE CLOUD DECK TO THE NORTH AND EAST. THINKING WE`LL RIDE THE EDGE FOR MUCH OF THE LATE AFTERNOON AND EVENING. WENT SCT AFTER 07Z...BUT LOW CONFIDENCE IN THIS AND WILL NEED TO CONTINUE EVALUATING CIG POTENTIAL FOR THE OVERNIGHT PERIOD. /OUTLOOK FOR KMSP/ TUE...VFR. WIND LIGHT/VARIABLE. WED...VFR. CHC MVFR. WIND SE 10 KT. THU...CHC MVFR/-SN. WIND NW 10-20 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ015- 016-025>028. && $$ SHORT TERM...SPD LONG TERM...JRB AVIATION...SPD
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
538 PM CST Tue Jan 27 2015 .SHORT TERM: (Through Late Tonight) Issued at 400 PM CST Tue Jan 27 2015 Surface ridge extending from WI southwest into northern MO will strengthen and move southeastward into the Ohio Valley region by 12Z Wednesday. Persistent low level cloud cover extends across eastern IA and much of IL this afternoon with some diurnally driven cloudiness across eastern MO. Much of the cloud cover over eastern MO should dissipate early this evening. The models try to slowly dissipate and advect eastward the more solid cloud cover across eastern IA and IL tonight. While this is possible due to at least weak subsidence across the area, would not be surprised if this cloud cover remains trapped under the inversion and actually retrogrades some westward tonight as the surface/boundary layer wind veers around to an easterly direction this evening. If this low level cloud cover remains through the night the MOS minimum temperature guidance may be a little too cool across the IL counties of our forecast area. Lows tonight across the western portion of the forecast area will be warmer despite less cloud cover due to increasing low level warm air advection on the nose of a southwesterly low level jet. GKS .LONG TERM: (Wednesday through Next Tuesday) Issued at 400 PM CST Tue Jan 27 2015 (Wednesday-Friday) 12z guidance continues to support thinking that a strong but brief warmup will occur tomorrow, followed by a cooling trend that should send temps to below average levels by the end of the work week. Have maintained current forecast highs for Wednesday, which is several degrees warmer than warmest GFS MAV. In spite of the very strong inversion that is forecast to limit mixing still think warmer is the way to go, as guidance hasn`t been robust enough the past few times we`ve had strong warming. I`m also uncertain how much cloudiness there will be; worse case for warming would be that this afternoon`s low clouds manage to hang around in the morning, but increasing southerly surface winds should advect them back out of the area for the afternoon. Cold front will sweep through the region Wednesday night, with the resultant cold advection only allowing a minimal daytime rebound during the day on Thursday. I have also continued some slight chance PoPs late Wednesday night and into Thursday morning as shortwave drops into the mid-Mississippi Valley, but moisture certainly looks scant at this time. The chunk of cold air that pushes into the area on Thursday should continue to exert its influence on Friday, with highs about a category lower than those on Thursday. (Saturday-Tuesday) Over the past few days models have come into much better agreement for this upcoming weekend, with upper low cutting off over the southwestern U.S. while fairly active westerlies continue from the Pacific NW, through the Mississippi Valley, into the east coast. All medium range guidance now supports the idea that broad overrunning will develop in the wake of the cold surface ridge on Saturday, which should lead to at least a chance of precip over much of the area. However, a strong shortwave in the westerlies will add additional large scale lift Saturday night and into Sunday, and have upped PoPs a bit more during this time. While precip is looking more promising, still lots of unknowns about ptype. 850mb temps are genenerally below 0C and certainly on Saturday evaporative cooling should try to cool the lower levels of the AMS enough to support snow. However, forecast soundings are also suggesting low level temp profile will become isothermal at around 0C on Saturday night and Sunday, which suggests ptype go be either liquid or frozen. I have leaned ptype a bit more towards snow, but still kept some mention of a mix because of the above thermal profile. A large chunk of very cold air will drop into the region behind the weekend system, and by the start of the new work week we will likely be reminded that winter is certainly not over. Have stayed with initialization guidance for highs on Monday...generally ranging from the lower 20s to the lower 30s. Truett && .AVIATION: (For the 00z TAFs through 00z Wednesday Evening) Issued at 532 PM CST Tue Jan 27 2015 Main concern for the overnight hours will be on stratus in Illinois. Dissipation has occurred over the past several hours on the western flank mainly due to diurnal effects. Will have to watch this area of stratus overnight as it is possible MVFR ceilings advect back southwestward into KUIN and the St. Louis metro TAF sites. RAP 925-950 hPa winds...albeit quite light...do suggest this may be possible as initially northerly winds in the aforementioned layer veer to the east and then eventually southeast overnight tonight. Otherwise...quiet and tranquil conditions are expected as sfc ridge of high pressure dominates the area with winds staying light overnight. By tomorrow/Wednesday...pressure gradient strengthens with winds becoming more southerly at the surface with wind gusts up to around 25 knots. Specifics for KSTL: Main concern for the overnight hours will be on stratus deck currently residing just east of the terminal. Dissipation has occurred over the past several hours on the western flank mainly due to diurnal effects...but will have to watch this area of stratus overnight as it is possible MVFR ceilings advect back southwestward into Lambert Field. RAP 925-950 hPa winds...albeit quite light...do suggest this may be possible as initially northerly winds in the aforementioned layer veer to the east and then eventually southeast overnight tonight. Otherwise...quiet and tranquil conditions are expected as sfc ridge of high pressure dominates the area with winds staying light overnight. By tomorrow/Wednesday...pressure gradient strengthens with winds becoming more southerly at the surface with wind gusts up to around 25 knots. Gosselin && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1141 PM CST Sun Jan 25 2015 .SHORT TERM: (Through Late Tonight) Issued at 323 PM CST Sun Jan 25 2015 Precip over the CWA should be winding down over the next few hours as upper level impulse works its way SE into the Ohio Valley. Deformation zone that was so well defined this morning over IA and n IL certainly falling apart as the afternoon progresses, and have used a combination of regional radar and HRRR for PoP/weather trends heading into the early evening. It would appear that the NW edge of the precip (now all snow) will be near a KCOU-KILX line by 00z, with the precip dropping southeast and exiting SE sections of the CWA no later than 06z. Surface obs trends this afternoon indicate that rain begins mixing with snow @ 36-37 and is all snow at 34 or colder, and will use this for ptypes for the rest of the afternoon and into the early evening. Given warm ground and the light intensity of the precip once it goes to all snow, accumulations should continue to be very minor. Other question for tonight is how much clearing will occur as the storm exits and a narrow ridge of high pressure works into the region. Over the last few hours have seen a wedge of clearing wrapping around the surface low from S WI into NE IA. Some of this clearing may reach our area, but there is also a lot of additional low cloud to our north that will advect our way as well, so for now have only gone with partial clearing during the late evening and overnight hours. Truett .LONG TERM: (Monday through Next Sunday) Issued at 323 PM CST Sun Jan 25 2015 (Monday-Wednesday) Overall, going forecast heading into midweek still looks pretty good, so this package will include generally minor adjustments and tweaks to these trends. Fast moving shortwave in northwest flow will zip into the region on Monday, with WAA in advance of this feature rapidly shutting down the CAA occuring overnight in the wake of today`s clipper. 12z synoptic runs are suggesting a fairly strong N-S warm front will be located near or just west of STL by late Monday afternoon and have attempted to reflect this in max temp forecast, allowing highs to rebound into the middle 50s over mid MO while keeping highs in the 30s over our S IL counties. This temp trend also seems to be supported by the model RH progs which suggest a fairly thick mid deck sweeping from W to E across the area in the zone of WAA during the day, with the most clouds over our eastern counties during the afternoon. Some 12z guidance is even trying to kick out some light QPF near and east of the Mississippi River in the zone of strongest WAA. Have continued dry forecast for now, but will need to keep an eye on this as there has been some very subtle suggestions of this for several days. The cold air advection behind Monday`s shortwave will try to dip into the area Monday night, but with the longwave trof working into the east coast during this time the main thrust of this cooler air will be east of our area. Model consensus of thermal profiles over the region support highs in the 40s over most of the CWA by Tuesday as weak surface ridge drops into the Mississippi Valley. Warmup still appears to be on schedule for Wednesday, and main question is how much of the warming will be able to translate to the surface. Forecast soundings are suggesting a large inversion, with low level mixing up to 900-950mb. Surface/low level winds...while strong...are going to primarily be southerly rather than the southwest direction that normally gives us our biggest warmups. Also some doubt to how much cloud cover there will be, as GFS suggests some mid clouds working into the area during the afternoon while NAM suggests lots of sunshine. Due to the above uncertainty will keep highs about where they are now...ranging from the mid 40s in our far eastern counties to near 60 in the far western tip of our CWA. (Thursday-Sunday) Shortwave that works across the region Wednesday night and early Thursday appears to be the first of several chunks of energy that will be deepening long wave trof over the eastern U.S. heading into the weekend, while cutoff low forms over the southwestern U.S. Medium range solutions are in very broad agreement in developing this split flow pattern, and in general this should mean temps trending back towards more wintry levels after the mid-week warmup. Will continue some slight chance PoPs on Wednesday night/Thursday for eastern parts of the FA in advance of aforementioned shortwave, with slight chance PoPs also continuing for parts of the FA on Saturday and Saturday night as there is agreement in the medium range models that WAA, a bit of shortwave energy, and a frontal boundary will be passing through the area at that time. Guidance is in reasonable agreement with their thermal profiles through Saturday, but much like yesterday the operational ECMWF continues to be deepest with the upper trof and much colder than the GFS by the end of the period (it`s intesting to note that last nights ECMWF-based MOS had over a 40 degree difference between the warm and cold members for Sunday`s highs (58 vs 16). For now, will lean towards MOS averages for temp trends on Sunday...which will be in the 30s. This seems to be a reasonable compromise at this point, with additional adjustments occurring as specific trends become less muddled. Truett && .AVIATION: (For the 06z TAFs through 06z Monday Night) Issued at 1132 PM CST Sun Jan 25 2015 Lingering MVFR SC deck to persist across most of taf sites through mid morning before scattering out. There is a hole in the mvfr deck that has made its way into KUIN but should see that fill back in by 08z Monday. Then next frontal boundary to move through and lower cigs back down to mvfr for tafs along and east of Mississippi river, while KCOU to remain vfr. As for winds, to persist from the north, then back to the southwest to south ahead of next front. Frontal boundary to move through KCOU by 22z Monday, KUIN by 23z Monday and metro area by 01z Tuesday. It will be a dry frontal passage with winds veering to the northwest. Specifics for KSTL: Lingering MVFR SC deck to persist across metro area through midday before lifting and scattering out. Then next frontal boundary to move through and lower cigs back down to mvfr by 01z Tuesday. As for winds, to persist from the north, then back to the south ahead of next front. Frontal passage will be a dry one with winds veering to the northwest. Byrd && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
905 AM PST MON JAN 26 2015 .SYNOPSIS...INCREASING CLOUDS EXPECTED TODAY WITH RAIN MOVING INTO PARTS OF NORTHWEST ARIZONA AND THE MOJAVE DESERT BY THE AFTERNOON. RAIN CHANCES WILL EXPAND NORTHWARD TONIGHT AND LIFT INTO THE GREAT BASIN TUESDAY. IMPROVING CONDITIONS ARE EXPECTED TUESDAY AFTERNOON THROUGH WEDNESDAY BEFORE THE POSSIBILITY OF MORE UNSETTLED WEATHER RETURNS LATE IN THE WEEK. && .UPDATE...RADAR DETECTING NARROW LINE OF LIGHT RAIN RUNNING FROM NEAR TWENTYNINE PALMS CA SOUTHEAST TOWARD YUMA AZ. BAND ASSOCIATED WITH JETSTREAK ACROSS SOUTHERN CALIFORNIA THIS MORNING. SEE A REPORT OF NEARLY TWO TENTH OF AN INCH FROM A STATION NORTH OF YUMA, OTHERWISE RAIN AMOUNTS RANGE FROM A FEW HUNDREDTHS OF AN INCH DOWN TO A TRACE. 12Z NAM/GFS PLUS THE 15Z HRRR SHIFT THIS BAND NORTHWEST ACROSS WESTERN SAN BERNARDINO COUNTY THIS AFTERNOON WITH ADDITIONAL BANDS DEVELOPING ACROSS EASTERN SAN BERNARDINO COUNTY AND SOUTHERN MOHAVE COUNTY. UPDATED EARLIER TO INCREASE POPS FOR SOUTHERN SAN BERNARDINO COUNTY AND THE AREA AROUND LAKE HAVASU CITY THIS AFTERNOON. A FEW 12Z MODELS NOW SUGGESTING RAIN BAND WILL BE MORE BROKEN AS IT LIFTS NORTH INTO SOUTHERN NEVADA TONIGHT. THIS EVENT NOW LOOKING MORE OF A HIGH POP, LOW QPF EVENT FOR THE LAS VEGAS VALLEY. WILL ADDRESS AND POTENTIAL CHANGES IN THE AFTERNOON PACKAGE. && .PREV DISCUSSION...326 AM PST MON JAN 26 2015 .SHORT TERM...THROUGH TUESDAY NIGHT. FAIRLY EXTENSIVE CLOUD SHIELD WRAPPING AROUND THE BAJA LOW IS NOW BEGINNING TO NUDGE INTO OUR SOUTHERN BORDER AND WILL CONTINUE TO INVADE OUR SKIES THROUGH THE EARLY MORNING HOURS. FOR THE MOST PART THE FORECAST REMAINS ON TRACK WITH SOME TENDENCY NOTED FOR THE MODELS TO TAKE THE HEAVIEST QPF UP THROUGH SAN BERNARDINO COUNTY AND INTO INYO COUNTY WITH LESSER AMOUNTS FURTHER EAST. REGARDLESS...I STILL ANTICIPATE A FAIRLY WIDESPREAD RAIN EVENT FOR OUR AREA. AS FOR THE DETAILS...RAIN WILL BEGIN TO BREAK OUT ACROSS SOUTHERN SAN BERNARDINO COUNTY BY LATE MORNING OR EARLY AFTERNOON. THE LATEST HRRR GUIDANCE HAS SOME LIGHT PRECIPITATION BREAKING OUT ROUGHLY SOUTH OF INTERSTATE 40 BY NOON. THIS PRECIP BAND WILL CONTINUE TO EXPAND THROUGH THE AFTERNOON WHILE SLOWLY LIFTING NORTHWARD. BY NIGHTFALL THE PRECIP BAND WILL CONTINUE TO WORK NORTHWARD INTO INYO COUNTY AS WELL ACROSS CLARK AND MOHAVE COUNTIES BEFORE LIFTING INTO OUR SOUTHERN GREAT BASIN ZONES EARLY TUESDAY MORNING. AS MENTIONED PREVIOUSLY...MODELS HAVE TRENDED TOWARDS TAKING THE BEST QPF INTO INYO COUNTY WITH LESSER AMOUNTS FURTHER EAST. IN FACT...IT LOOKS LIKE MUCH OF INYO COUNTY OUTSIDE OF THE LOWEST VALLEYS STAND A GOOD CHANCE TO PICK UP A QUARTER TO A HALF AN INCH OF PRECIPITATION...AND EVEN MORE ALONG THE SIERRA CREST. FURTHER EAST ACROSS CLARK AND MOHAVE COUNTY...I STILL ANTICIPATE WIDESPREAD RAIN BUT AMOUNTS MAY STRUGGLE TO EXCEED A TENTH OF AN INCH IN THE LOWEST DESERT VALLEYS. HOWEVER...PLAYING DEVILS ADVOCATE...WITH SUCH A MOISTURE RICH AIRMASS MOVING IN...IT WONT TAKE MUCH TO SQUEEZE OUT MORE PRECIP THAN INDICATED BY MODEL GUIDANCE. WITH ALL THIS IN MIND...IVE STAYED THE COURSE WITH THE FORECAST AND MAINTAINED SIMILAR QPF VALUES ACROSS THE LAS VEGAS METRO AS WHAT WAS INHERITED...WITH VALUES BETWEEN A TENTH AND A QUARTER OF AN INCH EXPECTED. FINALLY...SNOW LEVELS WILL BE RATHER HIGH FOR LATE JANUARY WITH THIS STORM THANKS TO THE SUBTROPICAL ORIGIN OF THE MOISTURE. SEVERAL INCHES OF SNOW ARE POSSIBLE ABOVE 7500 FEET PARTICULARLY ACROSS THE SIERRA AND AND ALSO THE HIGHEST REACHES OF THE SPRING MOUNTAINS. AFTER COORDINATING WITH THE NEIGHBORING OFFICES...DECIDED TO HOLD OFF ON ANY WINTER WEATHER HEADLINES FOR NOW. THE DAY SHIFT CAN REEVALUATE THE NEED FOR ANY ADVISORIES. ANY SNOW OF CONSEQUENCE WITH REGARDS TO IMPACTS WOULD BE AT ELEVATIONS ABOVE 8000 FEET SUCH AS THOSE LEADING TO LEE CANYON OR OVER THE SIERRA CREST. .LONG TERM...WEDNESDAY THROUGH SUNDAY. THE NEXT UPPER LEVEL DISTURBANCE TO AFFECT THE AREA WILL SLIDE INTO THE REGION ON THURSDAY AFTERNOON...REINTRODUCING PRECIPITATION CHANCES ACROSS MUCH OF THE AREA THROUGH SATURDAY. CURRENTLY THE PRIMARY CONCERN WITH THIS NEXT IMPULSE IS THE TIMING DIFFERENCES BETWEEN MODEL RUNS...WITH THE GFS BEING MUCH MORE PROGRESSIVE THAN THE EUROPEAN AND NAM. HOWEVER LOOKING AT RUN TO RUN CONSISTENCY...EACH MODEL HAS SHOWN SIGNS OF SPEEDING UP THIS NEXT IMPULSE TO SOME DEGREE OVER THE PAST FEW MODEL RUNS. THIS TREND WOULD SUPPORT LESS POPS WEST OF THE COLORADO RIVER AND WOULD FAVOR FAR EASTERN NEVADA AND ARIZONA FOR THE HIGHEST POPS. DID SLIGHTLY INCREASE POPS IN THESE AREAS FOR THESE REASONS AND THE FACT THAT SUFFICIENT UPPER DIFLUENCE CONTINUES TO LOOK MOST LIKELY THERE. MODELS CONTINUE TO SUPPORT THIS LOW WRAPPING UP AND MOVING SOUTHWARD AS HIGH PRESSURE BUILDS BACK INTO THE AREA DURING THE LATTER PART OF THE WEEKEND INTO EARLY NEXT WEEK. THIS WILL LEAD TO A DRYING TREND ACROSS THE AREA LATE SATURDAY THROUGH THE BEGINNING OF THE WEEK. THE WARM NATURE OF THIS SYSTEM WILL KEEP SNOW LEVELS HIGH FOR THIS TIME OF YEAR...WITH LEVELS AT OR AROUND 7000 FEET THROUGH THIS EVENT. TEMPERATURES WILL REMAIN A FEW DEGREES ABOVE NORMAL BEFORE A SLIGHT WARMING TREND OCCURS LATE THIS WEEKEND INTO THE BEGINNING OF THE WEEK. && .AVIATION...FOR MCCARRAN...INCREASING CLOUDS EXPECTED TODAY WITH RAIN EXPECTED TO IMPACT THE AIRFIELD TONIGHT AFTER 6Z. BIGGEST CONCERNS WILL BE REDUCTIONS IN VISIBILITY AND LOW CIGS. CIGS FALLING BELOW 5K EXPECTED AFTER 6Z AND POSSIBLY FALLING BELOW 3K AT TIMES DURING THE HEAVIEST RAINFALL. WINDS THROUGH THE PERIOD LOOK TO REMAIN LIGHT. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...INCREASING CLOUDS AND RAIN EXPECTED FOR MUCH OF THE AREA STARTING THIS AFTERNOON ACROSS AREAS SOUTH OF A KDAG-KEED-KIGM LINE AND LIFTING NORTH IN THE EVENING. REDUCTIONS IN VISIBILITY AND LOW CIGS EXPECTED IN THE HEAVIER RAINFALL WITH WIDESPREAD MOUNTAIN OBSCURATIONS EXPECTED. && .SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED BUT SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT RAIN OR SNOW IN THE COMING DAYS. && $$ UPDATE...PIERCE SHORT TERM/AVIATION...OUTLER LONG TERM...PULLIN FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE: HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
647 PM EST TUE JAN 27 2015 .SYNOPSIS... A STRONG COASTAL LOW PRESSURE EAST OF CAPE COD WILL SLOWLY MOVE AWAY FROM THE REGION TONIGHT...WITH AREAS OF SNOW TAPERING OFF TO SCATTERED FLURRIES BY WEDNESDAY MORNING. IN ADDITION...GUSTY NORTH WINDS WILL SLOWLY DECREASE AS SURFACE HIGH PRESSURE BUILDS INTO THE REGION. A FAST MOVING CLIPPER LIKE SYSTEM WILL IMPACT THE NORTH COUNTRY LATE THURSDAY INTO FRIDAY WITH ANOTHER ROUND OF LIGHT ACCUMULATING SNOW LIKELY. TEMPERATURES WILL START BELOW NORMAL...BUT WARM TO NEAR NORMAL LEVELS BY THURSDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 345 PM EST TUESDAY...AVE CANCELLED WINTER STORM WARNING AND REPLACED WITH WINTER WX ADVISORY FOR SNOW AND BLOWING SNOW. ALSO...EXPANDED ADVISORY TO COVER PARTS OF THE CHAMPLAIN AND WESTERN SLOPES FOR THE COMBINATION SNOW AND BLOWING SNOW THROUGH THE EVENING COMMUTE. EXPECTING A DIFFICULT EVENING COMMUTE ACROSS MOST THE REGION. BTV PICKED UP 3 INCHES OF SNOW IN JUST SEVERAL HRS UNDER THIS BAND OF HEAVY SNOW THIS AFTN. EXPECTING ADDITIONAL ACCUMULATIONS OF 1 TO 3 WITH LOCALIZED HIGHER AMOUNTS UNDER THIS NARROW MESO BAND OF MODERATE SNOW ACRS PORTIONS OF THE CHAMPLAIN AND WESTERN SLOPES. FCST CHALLENGE TONIGHT WL BE AREAL COVERAGE/INTENSITY OF SNOW THRU MIDNIGHT...ESPECIALLY FOR THE CHAMPLAIN VALLEY AND PARTS OF GREEN MTNS. CRNT WATER VAPOR SHOWS DEEP CLOSED CYCLONIC CIRCULATION JUST EAST OF CAPE COD THIS AFTN...WITH SEVERAL BAND OF MID/UPPER LVL MOISTURE ROTATING BACK TOWARD OUR CWA. WATER VAPOR AND RAP SHOWS THIS MID LVL MOISTURE AND ELONGATED 5H VORTICITY MAXIMUM WL BECOME STATIONARY ACRS THE CHAMPLAIN VALLEY/CENTRAL VT THIS AFTN/EVENING...WITH OCCASIONAL SNOW LINGERING THRU THE EVENING HRS. THIS SUPPORT ALOFT...COMBINED WITH FAVORABLE NORTHERLY FLW WL ENHANCE CONVERGENCE ON THE EASTERN SIDE OF THE CHAMPLAIN VALLEY...SUPPORTING LIGHT SNOW THRU 06Z...BEFORE TAPERING OFF TO FLURRIES. IN ADDITION...NAM FROUDE NUMBER SHOWS BLOCKED FLW WITH VALUES <0.50...SUPPORTING ENHANCED SNOWFALL ALONG AND UPSTREAM OF THE GREEN MTNS INTO THE CHAMPLAIN VALLEY. WL TRY TO SHOW THIS DETAIL IN THE GRIDS AND INCREASE THE SNOWFALL AMOUNTS SLIGHTLY ACRS THIS REGION...THINKING BTWN 1 AND 4 INCHES...WITH ISOLATED HIGHER AMOUNTS POSSIBLE. ELSEWHERE...AREAL COVERAGE OF MID LVL MOISTURE DECREASES RAPIDLY THIS AFTN/EVENING...AND ADDITIONAL SNOWFALL WL BE LIMITED. THIS IS ALREADY SUPPORTED BY RADAR SHOWING LARGE HOLE OF NO PRECIP ACRS MOST OF THE CT RIVER VALLEY AND NEK OF VT. ADDITIONAL SNOWFALL WL BE A DUSTING TO AN INCH OR TWO POSSIBLE IN THESE AREAS...WITH ONLY FLURRIES FOR THE SAINT LAWRENCE VALLEY/WESTERN DACKS. ALSO...EXPECT GUSTY NORTH WINDS TO CONTINUE...ESPECIALLY CHAMPLAIN VALLEY WITH SOME ENHANCED CHANNELING...WHICH WL CAUSE AREAS OF BLOWING AND DRIFTING SNOW. GUSTY TO 30 MPH WL BE LIKELY THRU 03Z TONIGHT. TEMPS WL REMAIN NEARLY STEADY IN THE SINGLE DIGITS ABOVE/BLW ZERO TO NEAR 10F MOST LOCATIONS. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AS OF 345 PM EST TUESDAY...SFC HIGH PRES BUILDS ACRS OUR CWA ON WEDS...RESULTING IN A SLOW WEST TO EAST CLRING TREND. GFS/ECMWF STILL SHOWS SOME LINGERING 850 TO 500MB RH ACRS OUR CENTRAL/EASTERN CWA THRU 15Z...BEFORE SHIFTING IT EASTWARD. LARGE SCALE SUBSIDENCE AND DEEP DRYING WL RESULT IN CLRING SKIES BY 18Z WEDS. NEXT FAST MOVING CLIPPER LIKE SYSTEM ARRIVES LATE THURS INTO FRIDAY. LATEST GUIDANCE TRACKS THIS SYSTEM ACRS OUR CWA...WHICH WL CAUSE A WIDESPREAD LIGHT SNOW EVENT. EXPECTING AN ADVISORY LVL EVENT WITH GENERAL ACCUMULATIONS OF 3 TO 5 INCHES...EXCEPT SLIGHTLY HIGHER AMOUNTS OF 6 INCHES IN THE FAVORABLE UPSLOPE REGIONS. TEMPS WL REBOUND TO NEAR NORMAL LEVELS AFTER A COLD START ON THURS MORNING. && .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 335 PM EST TUESDAY...AN ACTIVE PATTERN IS QUITE LIKELY FOR THE PERIOD, WITH TWO OPPORTUNITIES FOR SNOW AND SEVERAL DAYS WITH WELL BELOW NORMAL TEMPERATURES. GIVEN THE ONGOING WEATHER, AND FOCUS NEEDED ON THAT, I RELIED RATHER HEAVILY ON A "DOWN THE MIDDLE" MODEL BLEND FOR MOST OF THE FORECAST PERIOD, WITH ONLY A FEW MANUAL MODIFICATIONS. FROM WHAT I SAW, THE 12Z SUITE OF GFS, GFS ENSEMBLE AND ECMWF WERE ALL IN THE BALLPARK ENOUGH THAT A BLEND SHOULD WORK OUT PRETTY GOOD. DAILY DETAILS BELOW... FRIDAY: CLIPPER WILL BE QUICKLY EXITING DURING THE DAY, AND AS IT MOVES EAST OF HERE IT SHOULD STRENGTHEN ONCE IT REACHES THE "WARMER" ATLANTIC OCEAN WATERS. NET RESULT WILL BE AN INCREASE IN NORTHWEST WINDS -- COULD BE GUSTY AT TIMES. PAINTED IN SOME 20-30MPH GUSTS. THESE NORTHWEST WINDS WILL ALSO USHER IN COLDER AIR AS THE DAY GOES ON. DEFINITELY A NON-DIURNAL TEMPERATURE TREND WITH HIGHS FIRST THING. THE MID 20S "WARMTH" AT 8AM WILL END UP IN THE 5-15F RANGE BY EVENING TIME. COULD HAVE SOME WIND CHILL ISSUES TO TRACK COME FRIDAY/FRIDAY NIGHT. ON THE PRECIPITATION SIDE OF THINGS, SNOW SHOWERS FIRST THING IN THE DAY WILL DIMINISH AND BE MORE CONFINED TO THE MOUNTAINS BY AFTERNOON. IN THE END, LOOKS LIKE A SOLID 3-5" "ADVISORY" LEVEL EVENT (LOCALLY A BIT MORE IN THE NORTHERN MOUNTAINS). GENERALLY CLEAR AND COLD FRIDAY NIGHT. SUB- ZERO FOR EVERYBODY! SATURDAY: HIGH PRESSURE BUILDS IN. SHOULD BE SUNNY, BUT ALWAYS BEWARE OF SUNNY DAYS IN MID-WINTER. THAT MEANS COLD TOO. 925MB TEMPERATURES DOWN AROUND -20C. HIGHS 0 TO 8F WHERE WE LIVE. BRRR. WARM WEATHER FANS WILL NEED TO LOOK AT THE SUNNY SKIES AND PRETEND TO FEEL THE WARMTH. SATURDAY NIGHT - ANOTHER QUIET AND COLD NIGHT. SUB-ZERO FOR US ALL AGAIN. SUNDAY/MONDAY: FAST MOVING TROUGH IN THE UPPER FLOW WILL RESULT IN CYCLOGENESIS IN THE OHIO VALLEY SUNDAY, FOLLOWED BY PERHAPS THE DEVELOPMENT BY MONDAY OF A STRONG SURFACE LOW THAT WILL TRACK SOMEWHERE JUST SOUTH OF HERE. GFS SUGGEST JUST SOUTH OF LONG ISLAND. ECMWF IS A BIT FARTHER NORTH AND GOES ACROSS SOUTHERN NEW ENGLAND. HAVE GONE AHEAD AND BUMPED POPS UP TO THE 50-60% RANGE FOR SUNDAY NITE/MONDAY. CERTAINLY STILL A LOT OF UNCERTAINTY WITH REGARD TO TRACK AND INTENSITY. AT THIS POINT LOOKS LIKE AN ALL SNOW EVENT WITH LIKELY A PLOWABLE AMOUNT OF SNOW. HOWEVER, IF THE TRACK ENDS UP GOING A LITTLE FURTHER NORTH, THEN WE MAY BE LOOKING AT SOME MIXED PRECIPITATION ISSUES FOR PARTS OF THE FORECAST AREA. AS MENTIONED, EARLIER, JUST WENT WITH MODEL BLENDS FOR TEMPERATURES BUT ABOVE THE BLENDS FOR PRECIPITATION CHANCES. TUESDAY: ANOTHER SHOT OF BITTER ARCTIC AIR IN THE WAKE OF THE SUNDAY/MONDAY STORM. GFS IS BRUTALLY COLD. 925MB TEMPERATURES DOWN TO -35C! THE RAW MODEL SURFACE TEMPERATURE COME TUESDAY MORNING IS -25 TO -35F! (NOTE THAT MOS TURNS THAT INTO A -3F FOR BTV), AND HIGH TEMPERATURES WOULD ONLY BE -5 TO -15F. THE ECMWF IS "MUCH" WARMER -- 925MB TEMPERATURES OF -20C WITH IT`S RAW SURFACE TEMPERATURES ABOUT -15F IN THE MORNING WITH HIGHS -5 TO +5F. AT THIS POINT, HAVE MADE THE FORECAST CLOSER TO THE ECWMF. I DID WANT TO MAKE THE 7TH DAY OF THE FORECAST TO SHOW A +1C FOR A HIGH TEMPERATURE, JUST TO GIVE SOME HOPE TO WARM WEATHER FANS AFTER DAYS OF SUB-FREEZING (< 0C) HIGHS. BUT ALAS, IT WASN`T POSSIBLE. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... THROUGH 00Z THURSDAY...A VARIETY OF FLIGHT CATEGORIES WILL EXIST FOR MUCH OF TONIGHT BEFORE IMPROVING TO VFR AREA-WIDE ON WEDNESDAY. SNOW SHOWERS AND LOW STRATUS CONTINUE TO LINGER THIS EVENING AS COASTAL LOW DEPARTS THE NORTHEASTERN US. THESE WILL BE MOST PREVALENT AT MPV/BTV/PBG WHERE PERIODS OF IFR ARE LIKELY THROUGH 04Z-08Z. SNOW SHOWERS ALSO POSSIBLE AT RUT/SLK BUT WILL ONLY SHOW MVFR FOR NOW. MSS WILL REMAIN DRY. SNOW SHOWERS WILL TAPER OFF LATE TONIGHT AND EARLY WEDNESDAY MORNING. OTHERWISE LOW STRATUS WITH A MIX OF VFR/MVFR CEILINGS WILL PERSIST OVERNIGHT BEFORE IMPROVING AND SCATTERING OUT ON WEDNESDAY. GUSTY NORTHWEST WINDS WITH GUSTS UP TO 25 KNOTS CONTINUE INTO TONIGHT...GRADUALLY LESSENING AS THE NIGHT PROGRESSES. WINDS ON WEDNESDAY WILL BE NORTH/NORTHWEST FROM 5 TO 10 KNOTS AT BTV/RUT/MPV...NORTHEAST AT PBG FROM 5 TO 10 KNOTS...AND WEST/SOUTHWEST FROM 5 TO 10 KNOTS AT MSS/SLK. OUTLOOK 00Z THURSDAY THROUGH SUNDAY... 18Z WEDNESDAY THROUGH 00Z FRIDAY...VFR. 00Z FRIDAY THROUGH 00Z SATURDAY...MVFR/IFR IN PERIODS OF SNOW. 00Z SATURDAY ONWARD...VFR. && .EQUIPMENT... AS OF 122 PM EST MONDAY...THE KTYX 88D DOPPLER RADAR LOCATED NEAR WATERTOWN NEW YORK WILL BE DOWN AT LEAST THROUGH TUESDAY. THIS IS DUE TO A PEDESTAL DYNAMIC FAULT. ELECTRONICS TECHNICIANS HAVE ORDERED NEW PARTS TO FIX THIS PROBLEM. HOWEVER...THE NEW PARTS HAVE NOT ARRIVED AS OF THIS TIME AND THE KTYX RADAR WILL LIKELY NOT BE RESTORED TO SERVICE UNTIL SOMETIME THIS WEEK. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR VTZ002>012-016>019. NY...WINTER WEATHER ADVISORY UNTIL 1 AM EST WEDNESDAY FOR NYZ035. && $$ SYNOPSIS...TABER NEAR TERM...TABER SHORT TERM...TABER LONG TERM...NASH AVIATION...MUCCILLI/NASH EQUIPMENT...WFO BTV
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1231 PM EST MON JAN 26 2015 .SYNOPSIS... LOW PRESSURE AND A COLD FRONT WILL CROSS THE AREA TODAY AND CONGEAL INTO A POWERFUL NEW ENGLAND NOR`EASTER. HIGH PRESSURE WILL MOVE INTO THE CAROLINAS BY THURSDAY FOLLOWED BY ANOTHER COLD FRONT THURSDAY NIGHT INTO FRIDAY. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST OVER THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1230 PM MONDAY...AS EXPECTED CUMULUS CLOUDS ARE FILLING IN ACROSS SOUTH CAROLINA WHERE SUNNY SKIES ALLOWED TEMPERATURES TO SURGE INTO THE UPPER 50S THIS MORNING. THE LATEST HRRR SHOWS ISOLATED SHOWERS MAY BEGIN TO DEVELOP HERE AS EARLY AS 19Z/2 PM EST. OTHERWISE FEW CHANGES HAVE BEEN MADE TO THE FORECAST. PREVIOUS DISCUSSION FROM 930 AM FOLLOWS... COLD UPPER LEVEL LOW PRESSURE CENTERED OVER WESTERN VIRGINIA WILL MOVE OFF THE COAST THIS EVENING. UNTIL THEN...VERY CHILLY CONDITIONS AT 500 MB (TEMPS AS COLD AS -26C ACROSS SE NORTH CAROLINA) WILL CONTINUE...PRODUCING STEEP MID LEVEL LAPSE RATES AT OR JUST STEEPER THAN THE MOIST ADIABATIC LAPSE RATE. SATELLITE SHOWS CLEAR SKIES ACROSS MOST OF SOUTH CAROLINA AND SPREADING EASTWARD INTO SE NORTH CAROLINA. AS SUNSHINE HEATS TEMPERATURES INTO THE UPPER 50S WE EXPECT A HEALTHY CUMULUS CLOUD DECK TO DEVELOP THIS AFTERNOON WITH EMBEDDED TOWERING CUMULUS AND SHOWERY CB`S AS WELL. THIS BEST POTENTIAL INITIALLY SHOULD DEVELOP IN THE NC SOUTHERN PIEDMONT...ROTATING SOUTHEASTWARD TOWARD CAPE FEAR THIS EVENING. NOT EVERY LOCATION WILL SEE MEASURABLE RAIN. CHANGES TO THE FORECAST THIS MORNING INCLUDE BUMPING HIGHS UP TO NEAR 60 NEAR THE SANTEE RIVER...DELAYING THE DEVELOPMENT OF SHOWERS INTO THE EARLY-MID AFTERNOON HOURS...DELAYING THE ONSET OF CLEARING/ DRYING CONDITIONS THIS EVENING AS MOST OF THE LATEST MODEL DATA INDICATES SHOWERS SHOULD CONTINUE THROUGH THE EVENING NEAR CAPE FEAR. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...BLOCKBUSTER STORM CLOBBERING NEW ENGLAND ON TUESDAY AND AS AS USUAL WHEN THIS IS THE CASE COLD AIR WILL READILY INVADE MOST AREAS EAST OF THE APPALACHIANS. A SMALL LAYER OF LOW LEVEL MOISTURE STARTS OUT THE DAY BUT WITH A GREAT DEPTH OF THE COLUMN A DRY NWRLY FLOW THIS SHOULD MIX OUT FOR NEARLY FULL SUNSHINE. EVEN SO, THE CAA WILL CAP HIGHS IN THE MID 40S, SOME 10 DEGREES BELOW CLIMO. OFT TIMES WITH SUCH A LARGE AND STRENGTHENING STORM OVER THE NORTHEASTERN U.S. IT IS OFTEN RATHER BLUSTERY LOCALLY BUT THIS DOES NOT APPEAR TO BE IN THE OFFERING THIS TIME AROUND. WE SEEM TO FIND OURSELVES IN A RELATIVE MINIMUM IN THE LOW LEVEL WIND FIELD BETWEEN THE JET ASSOC WITH THE ACTUAL STORM CENTER AND THE MAIN AXIS OF COLD AIR ADVECTION WEST OF THE LOW LVL THERMAL TROUGH OVER THE GULF STATES. THERE WILL BE JUST ENOUGH WINDS TUESDAY NIGHT TO PREVENT RADIATIONAL COOLING. SO IN AN AIRMASS COLD ENOUGH TO BRING LOWS CLOSE TO 20 WE SHOULD INSTEAD REMAIN IN THE UPPER 20S...PERHAPS LOW 30S FAR SRN ZONES. UPPER TROUGH AXIS WELL OFFSHORE BY WEDNESDAY WHILE THE AXIS OF HIGHEST SURFACE PRESSURES BUILDS RIGHT OVERHEAD. SO WHILE THERE MAY BE SOME MINOR RECOVERY IN THE BOUNDARY LAYER TEMPERATURES THE SHALLOW NATURE OF THE MIXING (2200FT?) WILL BRING CHILLY HIGHS NEARLY IDENTICAL TO THOSE OBSERVED TUESDAY. FORECAST SOUNDINGS WEDNESDAY NIGHT MUCH MORE TYPICAL OF RADIATIONAL COOLING WITH NEAR ISOTHERMAL LAYER POSSIBLY AS DEEP AS 9KFT. HOWEVER DUE TO THE AFOREMENTIONED RECOVERY IN TEMPERATURES WEDNESDAY NIGHT LOWS WILL BE SIMILAR TO THOSE OF THE NIGHT BEFORE. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 AM MONDAY...SURFACE HIGH MOVES OVERHEAD EARLY THURSDAY AND JUST OFFSHORE IN A WEAKENING STATE LATER IN THE DAY. ZONAL MID LEVEL FLOW NORMAL QUITE DRY BUT SOME PVA INDUCED BY THE WESTERLIES REACTING WITH SOME LOW LEVEL MOISTURE FLOW IN THE SW WINDS TO BRING AN INCREASE IN CLOUDS. MEANWHILE AFTERNOON TEMPS REBOUND CLOSE TO CLIMO. WILL THIS MOISTURE BE ADEQUATE TO SUPPORT SOME PRECIPITATION AS THE NEXT UPPER WAVE AND COLD FRONT PASS THROUGH THURSDAY NIGHT INTO FRIDAY MORNING? HARD TO SAY THIS FAR OUT BUT GIVEN THE FAIRLY ROBUST STRENGTH OF THE TROUGH THE SLIGHT CHANCE INHERITED POPS LOOK FINE. EITHER WAY IT WILL STAY MILD ENOUGH TO PRECLUDE ANY PTYPE CONCERNS. THE WEEKEND WILL BASICALLY JUST FEATURE COLD AIR ADVECTION IN NORTHWESTERLY FLOW AROUND HUDSON BAY VORTEX. THERE MAY AT SOME TIME BE ENOUGH OF A SPOKE OF ENERGY WITHIN THIS FLOW TO YIELD ASCENT AND EVEN OFFSHORE PRESSURE FALLS. ANY SUCH DISTURBANCE IS FAR BEYOND BEING SAMPLED BY UPPER AIR NETWORK AND SO SOLUTIONS MAY SHOW HIGH VARIABILITY FROM RUN TO RUN. AT THIS TIME IT SEEMS MOST PRUDENT TO FOCUS ON THE CHILLY TEMPS AND ADDRESS ANY CLOUD COVER AND LOW RAIN CHANCES AT A FUTURE TIME. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 18Z...VFR CONDITIONS THIS AFTERNOON COULD GIVE WAY TO PERIODS OF MVFR CIGS IN THE LATE AFTERNOON AND EVENING HOURS. SFC HEATING WITH VERY COLD AIR ALOFT WILL ALLOW FOR ISO/SCT SHOWERS TO DEVELOP BY 20-21Z...MOST LIKELY OVER OUR NORTHERN TIER. THEREFORE...WILL MAINTAIN VCSH AT ALL TERMINALS AND INTRODUCE TEMPO -SHRA AT KLBT AND KILM THIS EVENING. DO NOT ANTICIPATE MUCH IN THE WAY OF AVIATION IMPACTS OTHER THAN MVFR CIGS AND PERHAPS TEMPO MVFR VSBYS. W-NW WINDS AROUND 10 KT WITH GUSTS OF 15-20 KT CAN BE EXPECTED TODAY INTO TONIGHT AS LOW PRESSURE BEGINS RAPIDLY DEEPENING OFF THE MID-ATLANTIC COAST. MVFR CIGS MAY LINGER OVERNIGHT...ESPECIALLY AT KILM AS MOISTURE WRAPS AROUND THE NOR`EASTER. ELSEWHERE...VFR CONDITIONS SHOULD PREVAIL AS THE LOW CLOUDS SCATTER OUT AND LOW PRESSURE LIFTS NORTHWARD. NW WINDS 8-12 KT WILL PERSIST INTO TUESDAY WITH A FEW HIGHER GUSTS POSSIBLE. EXTENDED OUTLOOK...VFR WILL PREVAIL TUESDAY THROUGH SATURDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1230 PM MONDAY...BUOYS REPORT LITTLE CHANGE IN SEA HEIGHT SINCE THE 930 AM UPDATE THIS MORNING. WEST WINDS HAVE ACTUALLY DECREASED IN SPEED A LITTLE BIT...POSSIBLY DUE TO DIURNAL HEATING EFFECTS INLAND. AS CLOUDS INCREASE INLAND WE HEAD TOWARD EVENING LOOK FOR WIND SPEEDS TO SURGE UP TOWARD 20-25 KT. PREVIOUS DISCUSSION FROM 930 AM FOLLOWS... BASED ON BUOY WAVE OBSERVATIONS OF 5.5 FEET FROM THE WILMINGTON "HARBOR" BUOY LOCATED ABOUT 5 MILES SOUTH OF THE MOUTH OF THE CAPE FEAR RIVER...I HAVE STARTED THE SMALL CRAFT ADVISORY EARLY (NOW) FOR ALL ZONES AS IT IS LIKELY 6 FOOT SEAS ARE BEING EXPERIENCED ACROSS AREAS WITH A LONG FETCH TO WESTERLY WINDS. LOW PRESSURE CENTERED OVER NORTHWESTERN NORTH CAROLINA WILL SHIFT ITS ENERGY OFF THE VIRGINIA COAST THIS AFTERNOON...AND THIS NEW LOW WILL BECOME THE DOMINANT FEATURE FOR EAST COAST WEATHER OVER THE NEXT 24 HOURS. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 300 AM MONDAY...MODERATE OFFSHORE FLOW ON TUESDAY AS LOW PRESSURE BOMB OFF THE NEW ENGLAND COAST BRINGS CYCLONIC FLOW ACROSS THE ENTIRE EAST COAST. DUE TO THE DISTANCE OF THIS STORM AND THE FACT THAT ITS BACKSWELL DOES NOT SIGNIFICANTLY REFRACT AROUND CAPE HATTERAS TOWARDS OUR REGION IT SEEMS THAT WE MAY NOT SEE ANY ADVISORIES SAVE FOR PERHAPS THE FIRST FEW HOURS OF THE PERIOD. THEREAFTER DECREASING WINDS AND SEAS EXPECTED AS THE GRADIENT EASES. NOT TOO FAR OFFSHORE HOWEVER THERE WILL STILL BE A BROAD AGITATED WIND FIELD AND MARINERS VENTURING OUT PAST OUR 20NM ZONES ARE URGED TO CHECK WITH THE OFFSHORE WATERS FORECAST FROM OPC. A FURTHER ABATING OF THE WIND FIELD IS SLATED FOR WEDNESDAY AND THE WIND DIRECTION WILL ALSO BE VEERING AS HIGH PRESSURE BUILDS IN FROM THE NORTHWEST...TAKING UP RESIDENCE ALONG THE COASTLINE BY AFTERNOON/EVENING. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 300 AM MONDAY...AN INITIALLY LIGHT SOUTH TO SOUTHWESTERLY RETURN FLOW WILL BECOME ESTABLISHED ACROSS THE SOUTHEAST AS A WEAKENING HIGH PRESSURE CELL MOVES OFF THE COAST. BY EVENING THIS WIND FIELD WILL INCREASE A BIT IN RESPONSE TO AN APPROACHING COLD FRONT FROM THE NORTHWEST. THE APPROACH AND PASSAGE OF THIS BOUNDARY WILL BRING AN EXTENDED PERIOD OF VEERING DIRECTION WHICH PAIRED WITH THE HIGHER WIND SPEEDS COULD LEAD TO SOME MARGINAL 6 FT SEAS OVER MAINLY NORTHERN ZONES. NW WINDS BEHIND THE FRONT ON FRIDAY WITH WIND AND SEAS BOTH SHOWING A DOWNWARD/IMPROVING TREND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL TO 7 AM EST TUESDAY FOR AMZ250-252-254-256. && $$ SYNOPSIS...MBB NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...BJR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
357 AM CST MON JAN 26 2015 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 355 AM CST MON JAN 26 2015 FORECAST CHALLENGES CONCERN MAINLY TEMPERATURES AND MID WEEK PCPN CHANCES WITH COLD FRONTAL PASSAGE. MODELS PRETTY CLOSE WITH THERMAL PROFILES BUT DIFFER ON SNOW POTENTIAL WITH MID WEEK CFP. MODELS HAVE OVERDONE QPF ON NEARLY EVERY OF THE RECENT WAVES IN NW FLOW SO FOR NOW WILL BE CONSERVATIVE WITH SNOW POTENTIAL. CURRENT RADAR RETURNS ASSOCIATED WITH MID LEVEL CLOUDS AROUND 10K FT SO PULLED POPS EXCEPT FOR THE FAR NE FA. EVEN THERE CANADIAN RADARS NOT IMPRESSIVE SO BACKED OFF ON COVERAGE THERE THIS MORNING. STRONG WARM ADVECTION WITH WESTERLY WINDS APPROACHING WESTERN VALLEY. BY 18Z OR SO SOME BACK DOOR COLD ADVECTION TAKES OVER. WESTWARD EXTENT OF LOWER CIGS WILL ALSO PLAY A PART ON HOW MUCH WE CAN RECOVER WITH MINIMAL SNOW COVER. SW FA INTO SOUTHERN VALLEY WILL HAVE BEST POTENTIAL FOR SOLAR SO HAVE WARMEST READINGS THERE. HIGH PRESSURE BUILDS INTO THE FA OVERNIGHT AND CLOUD COVER WILL AGAIN HAVE IMPACT ON TEMPERATURES SO STAYED CLOSE TO INHERITED VALUES. GOOD PUSH OF WARM ADVECTION TUESDAY WITH SOUTHERLY WINDS SO WILL BE ANOTHER DAY OF WELL ABOVE AVERAGE TEMPERATURES. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 355 AM CST MON JAN 26 2015 COLD FRONT LOOKS TO REMAIN NORTH OF FA UNTIL WEDNESDAY SO ANOTHER MILD NIGHT. COLD FRONTAL PASSAGE FROM N-S WEDNESDAY. MODELS SHOWING DIFFERENCES ON MAINLY POST FRONTAL PCPN POTENTIAL. BASED ON RECENT TRENDS OF OVER FORECASTING PCPN WITH THESE WAVES WILL KEEP POPS ON LOW END UNTIL CONFIDENCE INCREASES. LONG WAVE RIDGE REMAINS OVER WESTERN NORTH AMERICA AND LONG WAVE TROUGH OVER THE EASTERN NORTH AMERICA THROUGH THE PERIOD. LONG WAVE RIDGE BUILDS OVER THE BERING STRAITS AND INTO AK BY DAY 5 THEN WEAKENS. CROSS POLAR FLOW DEVELOPS THEREAFTER. THE ECMWF AND THE GFS WERE IN REASONABLE AGREEMENT AT THE BEGINNING OF THE PERIOD. THE ECMWF BECOMES A FASTER SOLUTION AND A MORE AMPLIFIED SOLUTION BY 00Z MON. MODELS DIVERGE SIGNIFICANTLY BY THE END OF THE PERIOD. GFS KEEPS THE SAME CURRENT PATTERN WITH SHORT WAVE RIDGES MOVING ACROSS THE NORTHERN PLAINS WHILE THE ECMWF INDICATED MORE SIGNIFICANT ARCTIC INTRUSIONS. WILL PREFER THE ECMWF. HIGH TEMPS WERE INCREASED TWO TO THREE DEGREES FOR THU AND ONE OR TWO DEGREES FOR FRI. HIGH TEMPS WERE DECREASED THREE TO SIX DEGREES ON SAT AND ONE TO THREE DEGREES ON SUN FROM YESTERDAYS FORECAST PACKAGE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1142 PM CST SUN JAN 25 2015 MODEL MOS GUIDANCE FOR CIGS HAVE BEEN WAY TOO PESSIMISTIC. THEY HOLD EVERYONE IN MVFR CIGS ALL NIGHT. THAT IS NOT THE CASE. MOST AREAS HAVE SEEN LOWER LEVEL CLOUDS EXIT AS DRY LOW LEVEL AIR MOVES IN. LEAVING SOME MID CLOUDS....EXCEPT FOR FAR NE FCST AREA. SATELLITE SHOWS A LARGE CLEAR AREA IN SW MANITOBA MOVING INTO NCNTRL ND AND THIS WILL SPREAD SOUTHEAST AS WELL. THUS KEPT MOST SITES VFR OVERNIGHT OR BECOMING THAT WAY. WINDS WILL BE SOUTH TO SOUTHWEST GUSTY AT TIMES TO 20-25KTS. MONDAY IS QUITE UNCERTAIN HOW CLOUDS WILL TREND. MVFR CIGS BEHIND THE LOW IN WEST CENTRAL MANITOBA UP NORTH OF DAUPHIN AND I THINK RAP MODEL HAS GOOD IDEA OF THAT MOVING SOUTH INTO MUCH OF THE FCST AREA DURING THE DAY MONDAY SO TRENDED IN THAT DIRECTION AS SFC WINDS TURN NORTHWEST. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SHORT TERM...VOELKER LONG TERM...HOPPES/VOELKER AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1245 AM CST MON JAN 26 2015 .UPDATE... ISSUED AT 1245 AM CST MON JAN 26 2015 WAA ACROSS THE AREA WILL BE REPLACED WITH WEAK CAA FOR THE REST OF THE MORNING AS LOW PRESSURE SLIDES SOUTHEAST INTO MINNESOTA. AREA OF LIGHT RAIN/FREEZING RAIN WILL PUSH OUT OF THE SOUTHERN JAMES RIVER VALLEY BY 09Z. NORTHWEST WINDS ARE ON THE INCREASE AS GRADIENT FORCING INCREASES ACROSS THE STATE. WINDS WILL SLOWLY SUBSIDE LATER THIS MORNING WEST TO EAST. TEMPERATURES WILL REMAIN STEADY OR RISING IN THE 30S FOR THE REST OF THE OVERNIGHT. UPPED SKY COVER A BIT WITH SCT-BKN MID LEVEL CLOUDS ALOFT AND EXPECTED TO CONTINUE TO STREAM IN FROM THE NORTH. UPDATE ISSUED AT 924 PM CST SUN JAN 25 2015 ENDED THE POPS BASED ON RADAR TRENDS AND LATEST HRRR RUNS. LEFT THE FORECAST DRY FOR TONIGHT. UPDATE ISSUED AT 648 PM CST SUN JAN 25 2015 BASED ON CANADIAN AND US RADARS AND LATEST HRRR MODEL WILL TRIM POPS AFTER 06Z TONIGHT AS HRRR MODEL TAKES THE LIGHT PRECIP EAST OF THE CWA. BOOSTED WINDS ABOUT 20 TO 30 MPH ACROSS PARTS OF THE NORTH AND EAST TONIGHT WITH STRENGTHENING PRESSURE GRADIENT AS JET MAX ALOFT MOVES THOUGH. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 322 PM CST SUN JAN 25 2015 ...RECORD HIGH TEMPERATURES FORECAST WEST MONDAY... A WARM FRONT IS CURRENTLY ENTERING THE MT/ND BORDER. THIS FRONT WILL CONTINUE TO PUSH EAST TONIGHT. THERE WILL BE A SLIGHT CHANCE FOR A WINTRY MIX OF RAIN...SLEET...AND FREEZING RAIN TO DEVELOP ALONG AND EAST OF A LINE FROM THE TURTLE MOUNTAIN REGION INTO THE JAMES RIVER VALLEY THIS EVENING. IMPACTS SHOULD BE MINIMAL...BUT NOT ZERO. THEREFORE...WILL LEAVE THE WINTRY MIX IMPACTS MENTION IN THE HWO FOR THIS UPDATE. AS WARM AIR ADVECTION DEVELOPS OVER WESTERN AND CENTRAL NORTH DAKOTA TONIGHT...TEMPERATURES SHOULD EITHER REMAIN STEADY OR SLOWLY INCREASE OVERNIGHT. ABOVE NORMAL LOWS ARE EXPECTED. DRY/WARM AIR IS PROGGED TO CONTINUE TO ADVECT INTO THE REGION MONDAY. SOME MAXIMUM TEMPERATURE RECORDS WILL BE IN JEOPARDY OF BEING BROKEN...ESPECIALLY OVER WESTERN NORTH DAKOTA. THE FOLLOWING TABLE IS A RUN DOWN OF THE FORECAST HIGHS AND ASSOCIATED RECORD HIGHS FOR SELECTED SITES ACROSS WESTERN AND CENTRAL NORTH DAKOTA. LOCATION MON HI TEMP MON HI TEMP FORECAST RECORD DICKINSON 53 49 IN 1931 WILLISTON 47 47 IN 2006 BISMARCK 48 52 IN 1942 MINOT 44 58 IN 1906 JAMESTOWN 42 52 IN 1990 .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 322 PM CST SUN JAN 25 2015 RECORD HIGH TEMPERATURES ARE POSSIBLE TUESDAY. AN UPPER LEVEL RIDGE WILL CENTER ACROSS WESTERN NORTH DAKOTA TUESDAY AFTERNOON WITH WARM AIR ADVECTION KICKING IN AHEAD OF A SURFACE LOW. THIS COMBINED WITH WEST...DOWNSLOPING WINDS...MINIMAL OR NONEXISTENT SNOWPACK AND PLENTY OF SUNSHINE...RECORD HIGH TEMPERATURES ARE POSSIBLE ON TUESDAY. THE 12 UTC ECMWF HAS 13-14 DEGREES CELSIUS AT 850MB WHILE THE GFS AND NAM SHOW CLOSER TO 11-12. IF THESE TEMPERATURES CAN MIX DOWN TO THE SURFACE IT SEEMS LIKELY THAT TEMPERATURES WILL CLIMB INTO THE UPPER 50S ACROSS THE SOUTHWEST. IT ISN`T COMPLETELY OUT OF THE REALM OF POSSIBILITY THAT A FEW AREAS REACH 60. LATER THIS WEEK WE WILL LIKELY TRANSITION INTO NORTHWEST FLOW WITH A TROUGH SPILLING INTO THE GREAT LAKES REGION. HOWEVER...LATEST MODELS TEND TO KEEP THE AXIS OF THE TROUGH A LITTLE FURTHER EAST. THIS WOULD MEAN TEMPERATURES ACROSS WESTERN AND CENTRAL NORTH DAKOTA MAY NOT COOL DOWN AS MUCH AS INITIALLY THOUGHT EARLIER. BUT...THIS IS STILL SEVERAL DAYS AWAY AND A LOT CAN CHANGE BETWEEN NOW AND THEN. IT DOES APPEAR WE WILL TRANSITION INTO A MORE ACTIVE PATTERN WITH SEVERAL CHANCE FOR LIGHT PRECIPITATION POSSIBLE LATER THIS WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1245 AM CST MON JAN 26 2015 VFR CONDITIONS THROUGH THE 06Z TAF PERIOD WITH A SCT-BKN MID LEVEL CLOUD DECK. A STEADY NORTHWEST WIND OF 15 TO NEAR 30 KTS FORECAST THROUGH THE MORNING. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...TM LONG TERM...AJ AVIATION...NH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1147 PM CST SUN JAN 25 2015 .UPDATE... ISSUED AT 1142 PM CST SUN JAN 25 2015 LAST PATCH OF FAST MOVING PRECIP MOVING INTO SE ND ATTM. PRODUCING A FEW SPRINKLES AND FARGO CAME NR 05Z WITH A FEW FLAKES. THIS ACTIVITY WILL MOVE OUT OF THE FCST AREA NEXT FEW HOURS. VERY DIFFICULT TO GET HANDLE ON HOW MUCH WAS REACHING THE GROUND...BUT BASED ON OBS AND DBZ ON RADAR SOME PRETTY VICIOUS VIRGA WAS OCCURRING TONIGHT. IF DRY LAYER NR 850 MB WASNT THERE A WHOLE DIFFERENT STORY. LIGHT SNOW IN LAKE OF THE WOODS REGION CONTINUES BUT CANADIAN RADAR AND OBS INDICATE MOST OF IT WILL EXIT EAST LATER TONGHT AND SNOW AMOUNTS LESS. LOWERED TO UP TO 1 INCH BAUDETTE AREA. TEMP SURGE IS ON AND EXPECT TEMPS TO RISE TO ABOVE FREEZING OVER ERN ND AND THE RRV AS THE NIGHT PROGRESSES...ALREADY THAT WAY IN DVL BASIN. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 300 PM CST SUN JAN 25 2015 THE MAIN CHALLENGE WILL BE LIGHT PRECIP TONIGHT THEN TEMPS. MODELS ARE IN GOOD OVERALL AGREEMENT...WITH JUST SOME SLIGHT TIMING DIFFERENCES. FOR TONIGHT...ISENTROPIC LIFT IN THE MID LEVELS AND A SPEED MAX WILL MOVE IN FAST NW FLOW ALOFT. THERE WILL BE A BAND OF LIGHT SNOW IN THE FAR NORTHEAST FA...WHERE UP TO AN INCH IS POSSIBLE. FURTHER TO THE SOUTH AND WEST...SOME FREEZING RAIN OR A MIX OF FREEZING RAIN/SNOW IS POSSIBLE. WE HAVE INTRODUCED POPS FOR THIS AND MENTIONED IN THE UPDATED WEATHER STORY. WE WILL NEED TO MONITOR THIS THREAT FOR ICING OVERNIGHT...EVEN WITH TEMPS RISING TO NEAR FREEZING LATE WITH INCREASING S/SW WINDS SHIFTING WEST LATE. ON MONDAY...SOME LINGERING LIGHT SNOW IS POSSIBLE IN NW MN DURING THE MORNING...OTHERWISE EXPECT A MILD AND DRY DAY WITH W/NW WINDS INCREASING INTO THE BREEZY CATEGORY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 300 PM CST SUN JAN 25 2015 ON TUE...EXPECT ANOTHER MILD AND DRY DAY WITH THE WARM WEATHER CONTINUING. TEMPS SHOULD CLIMB TO AROUND 40 WEST INTO THE MID 30S ELSEWHERE. IF THERE IS MORE INSOLATION THAN CURRENTLY PROGGED...TEMPS COULD BE EVEN WARMER. ON WED...A COLD FRONT WILL DROP FROM NORTH TO SOUTH THROUGH THE DAY. THERE SHOULD BE AT LEAST SOME LIGHT SNOW IN THE NORTHER AREAS. WE CAN/T RULE OUT SOME FREEZING DRIZZLE GIVEN THE WARM ENVIRONMENT...BUT FOR NOW WON/T MENTION BUT MONITOR THREAT. IT WILL BE MILD WITH TEMPS FALLING IN THE AFTERNOON BEHIND THE FRONT IN NORTHERN AREAS. FOR WED NIGHT THROUGH SAT...THE BEGINNING OF THE EXTENDED WILL START OUT WARM WITH TEMPS ABOVE NORMAL. THERE COULD BE SOME LIGHT SNOW WED NIGHT BEHIND A COOL FRONT...THEN AGAIN TOWARDS THE END OF NEXT WEEK. A MORE SIGNIFICANT COLD FRONT IS PROGGED BY NEXT SAT...THAT COULD MEAN AN END TO THE MILD TEMPS WE HAVE SEEN RECENTLY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1142 PM CST SUN JAN 25 2015 MODEL MOS GUIDANCE FOR CIGS HAVE BEEN WAY TOO PESSIMISTIC. THEY HOLD EVERYONE IN MVFR CIGS ALL NIGHT. THAT IS NOT THE CASE. MOST AREAS HAVE SEEN LOWER LEVEL CLOUDS EXIT AS DRY LOW LEVEL AIR MOVES IN. LEAVING SOME MID CLOUDS....EXCEPT FOR FAR NE FCST AREA. SATELLITE SHOWS A LARGE CLEAR AREA IN SW MANITOBA MOVING INTO NCNTRL ND AND THIS WILL SPREAD SOUTHEAST AS WELL. THUS KEPT MOST SITES VFR OVERNIGHT OR BECOMING THAT WAY. WINDS WILL BE SOUTH TO SOUTHWEST GUSTY AT TIMES TO 20-25KTS. MONDAY IS QUITE UNCERTAIN HOW CLOUDS WILL TREND. MVFR CIGS BEHIND THE LOW IN WEST CENTRAL MANITOBA UP NORTH OF DAUPHIN AND I THINK RAP MODEL HAS GOOD IDEA OF THAT MOVING SOUTH INTO MUCH OF THE FCST AREA DURING THE DAY MONDAY SO TRENDED IN THAT DIRECTION AS SFC WINDS TURN NORTHWEST. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...RIDDLE SHORT TERM...DK LONG TERM...GODON/DK AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1256 AM EST MON JAN 26 2015 .SYNOPSIS... THE CENTER OF AN ALBERTA CLIPPER WILL SWING THROUGH KENTUCKY OVERNIGHT. THIS WILL BE FOLLOWED BY A WEAK UPPER DISTURBANCE DROPPING ACROSS THE AREA MONDAY NIGHT INTO TUESDAY MORNING. HIGH PRESSURE WILL BUILD IN WEDNESDAY...BRINGING QUIET WEATHER FOR MID WEEK BEFORE YET ANOTHER SYSTEM BRINGS MIXED PRECIPITATION ON THURSDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... RAIN/SNOW LINE CONTINUES TO MAKE IT WAY SLOWLY SOUTH AND SOUTHEASTWARD. THE 1304 1000-850MB THICKNESS FROM THE RAP IS HANDLING THE CHANGEOVER NICELY. STARTING TO SEE SOME BREAKS IN THE PCPN IN THE WHITEWATER VALLEY AND THE BACKEDGE OF APPROACHING NE MERCER COUNTY. ONLY MADE A FEW TWEAKS IN THE PCPN FORECAST FOR TONIGHT. PRETTY MUCH KEPT THE SAME SNOW NUMBERS AND CHANGEOVER TIMING. DID SPEED UP THE ENDING OF THE SNOW LATE IN THE PERIOD. COLDER AIR HAS WORKED INTO THE N A LITTLE QUICKER THAN EXPECTED. KNOCKED A DEGREE OR SO OFF PREVIOUS LOWS TONIGHT. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... BECAUSE OF THE AMPLIFICATION AND THEREFOR SLOWER DEPARTURE OF THE SYSTEM WITH POTENTIAL FOR HIGHER SNOW RATIOS ON THE NW SIDE OF THE DEPARTING LOW...HAVE LINGERED SNOW ACCUMULATIONS A LITTLE IN AREAS S/E OF COLUMBUS WITH ADVISORY NOW IN EFFECT UNTIL 15Z AS WELL AS ADDING A COUPLE OF COUNTIES. SHOULD REMAIN A RUSH HOUR IMPACT IN ESPECIALLY AREAS EAST/SOUTHEAST OF COLUMBUS. LINGERING NON-ACCUMULATING SNOW SHOWERS TO LINGER BEHIND THE SYSTEM IN MAINLY THE FAR EASTERN FCST AREA...THEN WEAK SFC RIDGING BUILDS IN TO THE WEST IN THE 21Z-00Z TIMEFRAME. ONLY LOCATION TO RECEIVE SOME PARTIAL CLEARING WILL BE IN THE FAR NW AS MID/HIGH CLOUDS BUILD IN FROM ADVANCING WEAK S/WV FROM THE NORTHERN PLAINS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... THE GFS/NAM HAVE TRENDED A LITTLE FARTHER WEST IN REGARDS TO A WEAK S/WV DROPPING SOUTHEAST INTO THE MIDDLE OHIO VALLEY MONDAY NIGHT INTO TUESDAY. AS SUCH...IT NOW APPEARS THAT THE CHANCE OF LIGHT SNOW WITH THIS FEATURE MAY JUST GRAZE OUR FAR WEST/SOUTHWEST. HAVE ADJUSTED THE FORECAST TO REFLECT THIS. THERE WILL BE CONSIDERABLE CLOUDINESS THROUGH THE PERIOD. HIGH PRESSURE WILL BRIEFLY BUILD INTO THE AREA TUESDAY NIGHT INTO WEDNESDAY. COLD TEMPERATURES ON TUESDAY WILL MODIFY SOME BY WEDNESDAY. FOR THE PERIOD WEDNESDAY NIGHT INTO THURSDAY NIGHT...THE ECMWF AND THE GFS DIFFER IN THE TIMING OF A TANDEM OF S/WVS TO AFFECT THE REGION...ALONG WITH AN ASSOCIATED LOW PRESSURE/COLD FRONT. THE ECMWF IS SLOWER AND SHARPER WITH THE SECOND S/WV WHILE THE GFS IS FASTER. HAVE GONE WITH THE GFS TIMING AT THIS TIME TO KEEP CONTINUITY FROM PREVIOUS FORECAST. WITH RETURN FLOW...TEMPERATURES WILL BEGIN TO WARM SOME LATE WEDNESDAY NIGHT INTO THURSDAY. THERE WILL BE A RACE BETWEEN HOW FAST IT WARMS COMPARED TO WHEN THE ONSET OF PCPN BEGINS. AS STATED YESTERDAY...IT LOOKS LIKE THERE WILL BE SOME MIXED PCPN (-FZRA/-PL/-SN) EARLY ON BEFORE IT BECOMES RAIN/SNOW MIXED NORTH AND RAIN SOUTH BY THURSDAY AFTERNOON. GIVEN THAT THIS IS FOUR DAYS OUT AND IT IS HARD TO PINPOINT THE CHANGING THERMAL FIELDS EVEN IN THE SHORT TERM...HAVE CONTINUED WITH RAIN/SNOW WORDING ATTM. PCPN SHOULD CHANGE BACK TO SNOW THURSDAY NIGHT BEFORE ENDING BY FRIDAY MORNING. FOR FRIDAY INTO FRIDAY NIGHT...HIGH PRESSURE WILL ONCE AGAIN BUILD INTO THE REGION. TEMPERATURES WILL COOL BACK DOWN TO BELOW SEASONAL NORMALS. LONG RANGE MODELS DISAGREE ON HOW FAST A MAJOR WEATHER PATTERN CHANGE WILL OCCUR OVER THE WEEKEND INTO NEXT WEEK AS MUCH COLDER ARCTIC AIR PLUNGES SOUTHEAST INTO THE GREAT LAKES AND THE OHIO VALLEY. HAVE SIDED WITH THE ECMWF ATTM WHICH PUSHES AN ARCTIC FRONT INTO THE REGION DURING THE SATURDAY/SUNDAY TIME FRAME. WILL FORECAST A CHANCE OF SNOW WITH THIS SYSTEM. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... CLIPPER SYSTEM WILL CONTINUE TO MOVE THROUGH THE AREA OVERNIGHT AND INTO THE EARLY DAYTIME HOURS ON MONDAY. SNOW WILL BE PRESENT AT ALL AREA TAF SITES TO START THE TAF PERIOD. SNOW WILL GRADUALLY TAPER OFF FROM THE WESTERN TAF SITES TO THE EASTERN TAF SITES. CIGS WILL GENERALLY BE MVFR OVERNIGHT AND INTO THE DAYTIME MORNING HOURS ON MONDAY HOWEVER SOME BRIEF IFR CIGS CANNOT BE RULED OUT OVERNIGHT. VSBYS WITH THE SNOW WILL RANGE FROM IFR TO MVFR. WINDS WILL GUST AROUND 20 TO 25 KNOTS AT TIMES OVERNIGHT. HAVE CIGS IMPROVING TO VFR AT KCVG...KLUK...AND KDAY BY MID DAY ON MONDAY. KILN IS EXPECTED TO RETURN TO VFR CONDITIONS LATER IN THE DAY ON MONDAY. KCMH AND KLCK ARE EXPECTED TO HAVE MVFR CIGS THROUGH THE TAF PERIOD. OUTLOOK...MVFR CIGS AND VSBYS POSSIBLE THURSDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR OHZ026-034-035. WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR OHZ042>046-051>055-060>064-072. WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR OHZ056-065-073-074. KY...NONE. IN...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR INZ050. && $$ SYNOPSIS...JDR NEAR TERM...SITES SHORT TERM...JDR LONG TERM...HICKMAN AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
556 PM EST MON JAN 26 2015 .SYNOPSIS... PERIODS OF LIGHT SNOW WILL DECREASE ACROSS CENTRAL PENNSYLVANIA TONIGHT AS A STRONG COASTAL STORM TRACKS TOWARDS NEW ENGLAND TONIGHT. THE COASTAL STORM WILL RAPIDLY INTENSIFY TONIGHT AND TUESDAY...AS IT TRACKS EAST OF NEW ENGLAND. HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE MIDDLE OF THE WEEK...FOLLOWED BY AN ALBERTA CLIPPER THURSDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 600 PM UPDATE... EXTENDED THE ADVY FOR THOSE MIDDLE SUSQ COUNTIES THRU 11 PM...AS SNOW IS STILL FALLING AND IS NOT TAPERING OFF AS QUICKLY AS 4KM NAM/RAP/HRRR HAD PORTRAYED. MDLS CONTINUE TO INDICATE THAT THIS IS THE FIRST AREA OF THE CWA WHICH WILL HAVE THE SNOW DROP TO NOTHING. SNOW HAS RE-ENTERED/DEVELOPED OVER THE SE AND CURRENT NUMBERS STILL LOOK GOOD OVER THE WHOLE REGION. PREV... ADDED TIOGA CO TO THE ADVY AS SNOW SHOULD CONTINUE TO FALL THERE FOR ANOTHER FEW HRS AND THEY ARE ALREADY PUSHING 3-5 INCHES OF SNOW OFF THEIR CARS. HOWEVER...THE RAP AND HRRR BOTH SLIDE THE BIG BAND OFF TO THE WEST /NOT EAST/ SLIGHTLY - SO LESSER CHANCE FOR SULLIVAN CO PA TO GET TOO MUCH MORE. JUST UPPED POPS SLIGHTLY TO JUST BELOW 101 PERCENT IN THE CENTRAL AND WEST. PREV... DEFORMATION BETWEEN THE INVERTED SFC TROF OVER WESTERN AND SOUTHWESTERN PA AND RAPIDLY DEVELOPING COASTAL LOW OFF OF SOUTHEAST VA IS MAINTAINING CATEGORICAL POPS/SNOW ACROSS THE LAURELS AND CENTRAL/WEST CENTRAL/NORTHWEST/NORTHERN MOUNTAINS PRESENTLY. MY SOUTHEAST COUNTIES HAVE STARTED TO SEE SOME LIGHT ACTIVITY BUT IT IS STILL REMOVED FROM THE BETTER DEFORMATION ASSOCIATED WITH THE INVERTED TROF TO THE WEST AND THE INTENSIFYING LOW TO THE EAST. LOWERED THE LOWER END OF SNOW FAR RANGES FOR THE EAST IN WSW...GENERALLY 2 TO 5 INCHES EXPECTED OVERALL BEFORE ACCUM SNOWFALL EXITS PA BY DAYBREAK TUE MORNING. OVERALL HOWEVER...WIDESPREAD LIGHT SNOW WILL CONTINUE TO FALL OVR CENTRAL PA THIS EVENING INTO LATE TONIGHT ALONG THE AXIS OF DEEP EASTERLY FLOW BTWN LOW TO THE SOUTH AND HIGH PRES OVR NEW ENGLAND...FORCED LOCALLY BY THE INCREASING AFOREMENTIONED DEFORMATION. HI RES NAM/HRRR/WRF ARW ALL SUPPORT AN ADDITIONAL 1-3 INCHES TODAY...WITH THE HIGHEST AMTS ACROSS THE CENTRAL MTNS/ALLEGHENIES. KEEPING HEADLINES AS IS FOR NOW BUT SOME MAY NEED TO BE EXTENDED OVERNIGHT DEPENDING UPON WHERE THE DEFORMATION PROPOGATES. HRRR INDICATES A SOUTHWEST SHIFT TO THE FORCING AFTER 03Z...AS THE PARENT COASTAL CIRCULATION DOMINATES AND TAKES OVER EFFECTIVELY DISRUPTING AND ELIMINATING THE DEFORMATION FORCING SNOWFALL OVER CENTRAL PA BY 12Z. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... AS MENTIONED ABOVE...DEFORMATION SNOW SHOWERS SHOULD DWINDLE EARLY TUESDAY...WHILE NNW FLOW IN WAKE OF DEPARTING COASTAL LOW DRAWS MUCH DRIER AIR INTO CENTRAL PA. 25 TO 35KT NE WIND GUSTS WILL BE FELT AS TIGHT PRES GRADIENT IS REALIZED IN WAKE OF STORM JUST OFFSHORE OF SOUTHERN NEW ENGLAND COAST. AS PREVIOUSLY MENTIONED...THERE IS THE POTENTIAL OF SOME BLOWING/DRIFTING...ESP EASTERN PA WHERE BUKFIT SOUNDINGS SUPPORT GUSTS BTWN 30-35KTS. ENS MEAN 925 TEMPS SUPPORT MAX TEMPS TUE FROM NR 20F OVR THE N MTNS...TO ARND 32F ACROSS THE LOWER SUSQ VALLEY. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... DEEP STORM WILL PULL AWAY FROM PA TUESDAY NIGHT. WITH WINDS FROM THE NORTH...TOOK OUT SNOW SHOWERS FOR JST. SKIES SHOULD CLEAR OUT BY WED MORNING. MAIN CHANGE WAS WED NIGHT...DID LOWER TEMPS...BASED ON 12Z MODEL RUNS...AND THAT WITH MAINLY CLEAR SKIES AND LIGHT WINDS...EXPECT TEMPS TO DROP...WITH FRESH SNOW COVER. NEXT SYSTEM WILL BRING SOME SNOW SHOWERS TO THE AREA LATER THU INTO FRIDAY. THIS SYSTEM NOT LOOKING LIKE IT WOULD RESULT IN A COASTAL REAL NEAR THE COAST. COLDER AIR FOR FRIDAY NIGHT. WEEKEND NOT LOOKING TOO BAD...COLDER AIR WILL TRY TO BUILD IN EARLY NEXT WEEK. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... SENT OUT MORE ADJUSTMENTS AT 22Z. NW TO SE BANDS OF SNOW STILL LIFTING NORTHWARD FROM NEAR BWI. EARLIER DISCUSSION BELOW. REDUCTIONS CONTINUE REGIONWIDE AS INVERTED TROUGH LINGERS OVER CENTRAL PA /AND AS DEVELOPING NOR`EASTER BEGINS TO DEEPEN OFF MID ATLANTIC COAST/. EXPECT WIDESPREAD LIGHT SNOW TO CONTINUE THIS INTO TONIGHT WITH VSBYS VARYING FROM 1-4SM AND CIGS OF MVFR- IFR SETTLING BACK TOWARD A MORE ROBUST IFR DECK. NE WINDS WILL BE AROUND 10 MPH TODAY...AND PICK UP A BIT TO 10-15 MPH IN THE LOWER SUSQ TONIGHT AS STORM DEEPENS TO THE EAST AND SYNOPTIC FLOW INCREASES. IMPROVING CONDITIONS ON TUES AS HIGH PRESSURE BUILDS IN. SHOULD SEE VFR CONDITIONS IN CENTRAL AND EAST...WITH MVFR CIGS IN NW FLOW UNDER SUBSIDENCE INVERSION IN THE WESTERN HIGHER TERRAIN. NORTH WIND WILL BE BREEZY...PRODUCING SPEEDS OF 10-20 MPH. OUTLOOK... WED...VFR WITH NO SIG WEATHER EXPECTED. THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM THE WEST. THU NIGHT-FRI...WIDESPREAD IFR/MVFR IN SNOW. SAT...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ004>006- 010>012-017>019-024>026-033>036-045-058-059-064>066. WINTER WEATHER ADVISORY UNTIL 11 PM EST THIS EVENING FOR PAZ027-028-037-041-046-049>053-056-057-063. && $$ SYNOPSIS...DEVOIR/FITZGERALD NEAR TERM...DANGELO/DEVOIR/FITZGERALD SHORT TERM...DEVOIR/FITZGERALD LONG TERM...MARTIN AVIATION...DEVOIR/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
515 PM EST MON JAN 26 2015 .SYNOPSIS... PERIODS OF LIGHT SNOW WILL DECREASE ACROSS CENTRAL PENNSYLVANIA TONIGHT AS A STRONG COASTAL STORM TRACKS TOWARDS NEW ENGLAND TONIGHT. THE COASTAL STORM WILL RAPIDLY INTENSIFY TONIGHT AND TUESDAY...AS IT TRACKS EAST OF NEW ENGLAND. HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE MIDDLE OF THE WEEK...FOLLOWED BY AN ALBERTA CLIPPER THURSDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... ADDED TIOGA CO TO THE ADVY AS SNOW SHOULD CONTINUE TO FALL THERE FOR ANOTHER FEW HRS AND THEY ARE ALREADY PUSHING 3-5 INCHES OF SNOW OFF THEIR CARS. HOWEVER...THE RAP AND HRRR BOTH SLIDE THE BIG BAND OFF TO THE WEST /NOT EAST/ SLIGHTLY - SO LESSER CHANCE FOR SULLIVAN CO PA TO GET TOO MUCH MORE. JUST UPPED POPS SLIGHTLY TO JUST BELOW 101 PERCENT IN THE CENTRAL AND WEST. PREV... DEFORMATION BETWEEN THE INVERTED SFC TROF OVER WESTERN AND SOUTHWESTERN PA AND RAPIDLY DEVELOPING COASTAL LOW OFF OF SOUTHEAST VA IS MAINTAINING CATEGORICAL POPS/SNOW ACROSS THE LAURELS AND CENTRAL/WEST CENTRAL/NORTHWEST/NORTHERN MOUNTAINS PRESENTLY. MY SOUTHEAST COUNTIES HAVE STARTED TO SEE SOME LIGHT ACTIVITY BUT IT IS STILL REMOVED FROM THE BETTER DEFORMATION ASSOCIATED WITH THE INVERTED TROF TO THE WEST AND THE INTENSIFYING LOW TO THE EAST. LOWERED THE LOWER END OF SNOW FAR RANGES FOR THE EAST IN WSW...GENERALLY 2 TO 5 INCHES EXPECTED OVERALL BEFORE ACCUM SNOWFALL EXITS PA BY DAYBREAK TUE MORNING. OVERALL HOWEVER...WIDESPREAD LIGHT SNOW WILL CONTINUE TO FALL OVR CENTRAL PA THIS EVENING INTO LATE TONIGHT ALONG THE AXIS OF DEEP EASTERLY FLOW BTWN LOW TO THE SOUTH AND HIGH PRES OVR NEW ENGLAND...FORCED LOCALLY BY THE INCREASING AFOREMENTIONED DEFORMATION. HI RES NAM/HRRR/WRF ARW ALL SUPPORT AN ADDITIONAL 1-3 INCHES TODAY...WITH THE HIGHEST AMTS ACROSS THE CENTRAL MTNS/ALLEGHENIES. KEEPING HEADLINES AS IS FOR NOW BUT SOME MAY NEED TO BE EXTENDED OVERNIGHT DEPENDING UPON WHERE THE DEFORMATION PROPOGATES. HRRR INDICATES A SOUTHWEST SHIFT TO THE FORCING AFTER 03Z...AS THE PARENT COASTAL CIRCULATION DOMINATES AND TAKES OVER EFFECTIVELY DISRUPTING AND ELIMINATING THE DEFORMATION FORCING SNOWFALL OVER CENTRAL PA BY 12Z. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... AS MENTIONED ABOVE...DEFORMATION SNOW SHOWERS SHOULD DWINDLE EARLY TUESDAY...WHILE NNW FLOW IN WAKE OF DEPARTING COASTAL LOW DRAWS MUCH DRIER AIR INTO CENTRAL PA. 25 TO 35KT NE WIND GUSTS WILL BE FELT AS TIGHT PRES GRADIENT IS REALIZED IN WAKE OF STORM JUST OFFSHORE OF SOUTHERN NEW ENGLAND COAST. AS PREVIOUSLY MENTIONED...THERE IS THE POTENTIAL OF SOME BLOWING/DRIFTING...ESP EASTERN PA WHERE BUKFIT SOUNDINGS SUPPORT GUSTS BTWN 30-35KTS. ENS MEAN 925 TEMPS SUPPORT MAX TEMPS TUE FROM NR 20F OVR THE N MTNS...TO ARND 32F ACROSS THE LOWER SUSQ VALLEY. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... DEEP STORM WILL PULL AWAY FROM PA TUESDAY NIGHT. WITH WINDS FROM THE NORTH...TOOK OUT SNOW SHOWERS FOR JST. SKIES SHOULD CLEAR OUT BY WED MORNING. MAIN CHANGE WAS WED NIGHT...DID LOWER TEMPS...BASED ON 12Z MODEL RUNS...AND THAT WITH MAINLY CLEAR SKIES AND LIGHT WINDS...EXPECT TEMPS TO DROP...WITH FRESH SNOW COVER. NEXT SYSTEM WILL BRING SOME SNOW SHOWERS TO THE AREA LATER THU INTO FRIDAY. THIS SYSTEM NOT LOOKING LIKE IT WOULD RESULT IN A COASTAL REAL NEAR THE COAST. COLDER AIR FOR FRIDAY NIGHT. WEEKEND NOT LOOKING TOO BAD...COLDER AIR WILL TRY TO BUILD IN EARLY NEXT WEEK. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... SENT OUT MORE ADJUSTMENTS AT 22Z. NW TO SE BANDS OF SNOW STILL LIFTING NORTHWARD FROM NEAR BWI. EARLIER DISCUSSION BELOW. REDUCTIONS CONTINUE REGIONWIDE AS INVERTED TROUGH LINGERS OVER CENTRAL PA /AND AS DEVELOPING NOR`EASTER BEGINS TO DEEPEN OFF MID ATLANTIC COAST/. EXPECT WIDESPREAD LIGHT SNOW TO CONTINUE THIS INTO TONIGHT WITH VSBYS VARYING FROM 1-4SM AND CIGS OF MVFR- IFR SETTLING BACK TOWARD A MORE ROBUST IFR DECK. NE WINDS WILL BE AROUND 10 MPH TODAY...AND PICK UP A BIT TO 10-15 MPH IN THE LOWER SUSQ TONIGHT AS STORM DEEPENS TO THE EAST AND SYNOPTIC FLOW INCREASES. IMPROVING CONDITIONS ON TUES AS HIGH PRESSURE BUILDS IN. SHOULD SEE VFR CONDITIONS IN CENTRAL AND EAST...WITH MVFR CIGS IN NW FLOW UNDER SUBSIDENCE INVERSION IN THE WESTERN HIGHER TERRAIN. NORTH WIND WILL BE BREEZY...PRODUCING SPEEDS OF 10-20 MPH. OUTLOOK... WED...VFR WITH NO SIG WEATHER EXPECTED. THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM THE WEST. THU NIGHT-FRI...WIDESPREAD IFR/MVFR IN SNOW. SAT...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ004>006- 010>012-017>019-024>026-033>036-045-058-059-064>066. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ027- 028-037-041-046-049>053-056-057-063. && $$ SYNOPSIS...DEVOIR/FITZGERALD NEAR TERM...DANGELO/DEVOIR/FITZGERALD SHORT TERM...DEVOIR/FITZGERALD LONG TERM...MARTIN AVIATION...DEVOIR/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
433 PM EST MON JAN 26 2015 .SYNOPSIS... PERIODS OF LIGHT SNOW WILL DECREASE ACROSS CENTRAL PENNSYLVANIA TONIGHT AS A STRONG COASTAL STORM TRACKS TOWARDS NEW ENGLAND TONIGHT. THE COASTAL STORM WILL RAPIDLY INTENSIFY TONIGHT AND TUESDAY...AS IT TRACKS EAST OF NEW ENGLAND. HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE MIDDLE OF THE WEEK...FOLLOWED BY AN ALBERTA CLIPPER THURSDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... ADDED TIOGA CO TO THE ADVY AS SNOW SHOULD CONTINUE TO FALL THERE FOR ANOTHER FEW HRS AND THEY ARE ALREADY PUSHING 3-5 INCHES OF SNOW OFF THEIR CARS. HOWEVER...THE RAP AND HRRR BOTH SLIDE THE BIG BAND OFF TO THE WEST /NOT EAST/ SLIGHTLY - SO LESSER CHANCE FOR SULLIVAN CO PA TO GET TOO MUCH MORE. JUST UPPED POPS SLIGHTLY TO JUST BELOW 101 PERCENT IN THE CENTRAL AND WEST. PREV... DEFORMATION BETWEEN THE INVERTED SFC TROF OVER WESTERN AND SOUTHWESTERN PA AND RAPIDLY DEVELOPING COASTAL LOW OFF OF SOUTHEAST VA IS MAINTAINING CATEGORICAL POPS/SNOW ACROSS THE LAURELS AND CENTRAL/WEST CENTRAL/NORTHWEST/NORTHERN MOUNTAINS PRESENTLY. MY SOUTHEAST COUNTIES HAVE STARTED TO SEE SOME LIGHT ACTIVITY BUT IT IS STILL REMOVED FROM THE BETTER DEFORMATION ASSOCIATED WITH THE INVERTED TROF TO THE WEST AND THE INTENSIFYING LOW TO THE EAST. LOWERED THE LOWER END OF SNOW FAR RANGES FOR THE EAST IN WSW...GENERALLY 2 TO 5 INCHES EXPECTED OVERALL BEFORE ACCUM SNOWFALL EXITS PA BY DAYBREAK TUE MORNING. OVERALL HOWEVER...WIDESPREAD LIGHT SNOW WILL CONTINUE TO FALL OVR CENTRAL PA THIS EVENING INTO LATE TONIGHT ALONG THE AXIS OF DEEP EASTERLY FLOW BTWN LOW TO THE SOUTH AND HIGH PRES OVR NEW ENGLAND...FORCED LOCALLY BY THE INCREASING AFOREMENTIONED DEFORMATION. HI RES NAM/HRRR/WRF ARW ALL SUPPORT AN ADDITIONAL 1-3 INCHES TODAY...WITH THE HIGHEST AMTS ACROSS THE CENTRAL MTNS/ALLEGHENIES. KEEPING HEADLINES AS IS FOR NOW BUT SOME MAY NEED TO BE EXTENDED OVERNIGHT DEPENDING UPON WHERE THE DEFORMATION PROPOGATES. HRRR INDICATES A SOUTHWEST SHIFT TO THE FORCING AFTER 03Z...AS THE PARENT COASTAL CIRCULATION DOMINATES AND TAKES OVER EFFECTIVELY DISRUPTING AND ELIMINATING THE DEFORMATION FORCING SNOWFALL OVER CENTRAL PA BY 12Z. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... AS MENTIONED ABOVE...DEFORMATION SNOW SHOWERS SHOULD DWINDLE EARLY TUESDAY...WHILE NNW FLOW IN WAKE OF DEPARTING COASTAL LOW DRAWS MUCH DRIER AIR INTO CENTRAL PA. 25 TO 35KT NE WIND GUSTS WILL BE FELT AS TIGHT PRES GRADIENT IS REALIZED IN WAKE OF STORM JUST OFFSHORE OF SOUTHERN NEW ENGLAND COAST. AS PREVIOUSLY MENTIONED...THERE IS THE POTENTIAL OF SOME BLOWING/DRIFTING...ESP EASTERN PA WHERE BUKFIT SOUNDINGS SUPPORT GUSTS BTWN 30-35KTS. ENS MEAN 925 TEMPS SUPPORT MAX TEMPS TUE FROM NR 20F OVR THE N MTNS...TO ARND 32F ACROSS THE LOWER SUSQ VALLEY. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... DEEP STORM WILL PULL AWAY FROM PA TUESDAY NIGHT. WITH WINDS FROM THE NORTH...TOOK OUT SNOW SHOWERS FOR JST. SKIES SHOULD CLEAR OUT BY WED MORNING. MAIN CHANGE WAS WED NIGHT...DID LOWER TEMPS...BASED ON 12Z MODEL RUNS...AND THAT WITH MAINLY CLEAR SKIES AND LIGHT WINDS...EXPECT TEMPS TO DROP...WITH FRESH SNOW COVER. NEXT SYSTEM WILL BRING SOME SNOW SHOWERS TO THE AREA LATER THU INTO FRIDAY. THIS SYSTEM NOT LOOKING LIKE IT WOULD RESULT IN A COASTAL REAL NEAR THE COAST. COLDER AIR FOR FRIDAY NIGHT. WEEKEND NOT LOOKING TOO BAD...COLDER AIR WILL TRY TO BUILD IN EARLY NEXT WEEK. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... REDUCTIONS CONTINUE REGIONWIDE AS INVERTED TROUGH LINGERS OVER CENTRAL PA /AND AS DEVELOPING NOR`EASTER BEGINS TO DEEPEN OFF MID ATLANTIC COAST/. EXPECT WIDESPREAD LIGHT SNOW TO CONTINUE THIS INTO TONIGHT WITH VSBYS VARYING FROM 1-4SM AND CIGS OF MVFR- IFR SETTLING BACK TOWARD A MORE ROBUST IFR DECK. NE WINDS WILL BE AROUND 10 MPH TODAY...AND PICK UP A BIT TO 10-15 MPH IN THE LOWER SUSQ TONIGHT AS STORM DEEPENS TO THE EAST AND SYNOPTIC FLOW INCREASES. IMPROVING CONDITIONS ON TUES AS HIGH PRESSURE BUILDS IN. SHOULD SEE VFR CONDITIONS IN CENTRAL AND EAST...WITH MVFR CIGS IN NW FLOW UNDER SUBSIDENCE INVERSION IN THE WESTERN HIGHER TERRAIN. NORTH WIND WILL BE BREEZY...PRODUCING SPEEDS OF 10-20 MPH. OUTLOOK... WED...VFR WITH NO SIG WEATHER EXPECTED. THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM THE WEST. THU NIGHT-FRI...WIDESPREAD IFR/MVFR IN SNOW. SAT...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ004>006- 010>012-017>019-024>026-033>036-045-058-059-064>066. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ027- 028-037-041-046-049>053-056-057-063. && $$ SYNOPSIS...DEVOIR/FITZGERALD NEAR TERM...DANGELO/DEVOIR/FITZGERALD SHORT TERM...DEVOIR/FITZGERALD LONG TERM...MARTIN AVIATION...DEVOIR/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
432 PM EST MON JAN 26 2015 .SYNOPSIS... PERIODS OF LIGHT SNOW WILL DECREASE ACROSS CENTRAL PENNSYLVANIA TONIGHT AS A STRONG COASTAL STORM TRACKS TOWARDS NEW ENGLAND TONIGHT. THE COASTAL STORM WILL RAPIDLY INTENSIFY TONIGHT AND TUESDAY...AS IT TRACKS EAST OF NEW ENGLAND. HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE MIDDLE OF THE WEEK...FOLLOWED BY AN ALBERTA CLIPPER THURSDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... ADDED TIOGA CO TO THE ADVY AS SNOW SHOULD CONTINUE TO FALL THERE FOR ANOTHER FEW HRS AND THEY ARE ALREADY PUSHING 3-5 INCHES OF SNOW OFF THEIR CARS. HOWEVER...THE RAP AND HRRR BOTH SLIDE THE BIG BAND OFF TO THE EAST SLIGHTLY - SO LESSER CHANCE FOR SULLIVAN CO PA TO GET TOO MUCH MORE. JUST UPPED POPS SLIGHTLY TO JUST BELOW 101 PERCENT IN THE CENTRAL AND WEST. PREV... DEFORMATION BETWEEN THE INVERTED SFC TROF OVER WESTERN AND SOUTHWESTERN PA AND RAPIDLY DEVELOPING COASTAL LOW OFF OF SOUTHEAST VA IS MAINTAINING CATEGORICAL POPS/SNOW ACROSS THE LAURELS AND CENTRAL/WEST CENTRAL/NORTHWEST/NORTHERN MOUNTAINS PRESENTLY. MY SOUTHEAST COUNTIES HAVE STARTED TO SEE SOME LIGHT ACTIVITY BUT IT IS STILL REMOVED FROM THE BETTER DEFORMATION ASSOCIATED WITH THE INVERTED TROF TO THE WEST AND THE INTENSIFYING LOW TO THE EAST. LOWERED THE LOWER END OF SNOW FAR RANGES FOR THE EAST IN WSW...GENERALLY 2 TO 5 INCHES EXPECTED OVERALL BEFORE ACCUM SNOWFALL EXITS PA BY DAYBREAK TUE MORNING. OVERALL HOWEVER...WIDESPREAD LIGHT SNOW WILL CONTINUE TO FALL OVR CENTRAL PA THIS EVENING INTO LATE TONIGHT ALONG THE AXIS OF DEEP EASTERLY FLOW BTWN LOW TO THE SOUTH AND HIGH PRES OVR NEW ENGLAND...FORCED LOCALLY BY THE INCREASING AFOREMENTIONED DEFORMATION. HI RES NAM/HRRR/WRF ARW ALL SUPPORT AN ADDITIONAL 1-3 INCHES TODAY...WITH THE HIGHEST AMTS ACROSS THE CENTRAL MTNS/ALLEGHENIES. KEEPING HEADLINES AS IS FOR NOW BUT SOME MAY NEED TO BE EXTENDED OVERNIGHT DEPENDING UPON WHERE THE DEFORMATION PROPOGATES. HRRR INDICATES A SOUTHWEST SHIFT TO THE FORCING AFTER 03Z...AS THE PARENT COASTAL CIRCULATION DOMINATES AND TAKES OVER EFFECTIVELY DISRUPTING AND ELIMINATING THE DEFORMATION FORCING SNOWFALL OVER CENTRAL PA BY 12Z. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... AS MENTIONED ABOVE...DEFORMATION SNOW SHOWERS SHOULD DWINDLE EARLY TUESDAY...WHILE NNW FLOW IN WAKE OF DEPARTING COASTAL LOW DRAWS MUCH DRIER AIR INTO CENTRAL PA. 25 TO 35KT NE WIND GUSTS WILL BE FELT AS TIGHT PRES GRADIENT IS REALIZED IN WAKE OF STORM JUST OFFSHORE OF SOUTHERN NEW ENGLAND COAST. AS PREVIOUSLY MENTIONED...THERE IS THE POTENTIAL OF SOME BLOWING/DRIFTING...ESP EASTERN PA WHERE BUKFIT SOUNDINGS SUPPORT GUSTS BTWN 30-35KTS. ENS MEAN 925 TEMPS SUPPORT MAX TEMPS TUE FROM NR 20F OVR THE N MTNS...TO ARND 32F ACROSS THE LOWER SUSQ VALLEY. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... DEEP STORM WILL PULL AWAY FROM PA TUESDAY NIGHT. WITH WINDS FROM THE NORTH...TOOK OUT SNOW SHOWERS FOR JST. SKIES SHOULD CLEAR OUT BY WED MORNING. MAIN CHANGE WAS WED NIGHT...DID LOWER TEMPS...BASED ON 12Z MODEL RUNS...AND THAT WITH MAINLY CLEAR SKIES AND LIGHT WINDS...EXPECT TEMPS TO DROP...WITH FRESH SNOW COVER. NEXT SYSTEM WILL BRING SOME SNOW SHOWERS TO THE AREA LATER THU INTO FRIDAY. THIS SYSTEM NOT LOOKING LIKE IT WOULD RESULT IN A COASTAL REAL NEAR THE COAST. COLDER AIR FOR FRIDAY NIGHT. WEEKEND NOT LOOKING TOO BAD...COLDER AIR WILL TRY TO BUILD IN EARLY NEXT WEEK. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... REDUCTIONS CONTINUE REGIONWIDE AS INVERTED TROUGH LINGERS OVER CENTRAL PA /AND AS DEVELOPING NOR`EASTER BEGINS TO DEEPEN OFF MID ATLANTIC COAST/. EXPECT WIDESPREAD LIGHT SNOW TO CONTINUE THIS INTO TONIGHT WITH VSBYS VARYING FROM 1-4SM AND CIGS OF MVFR- IFR SETTLING BACK TOWARD A MORE ROBUST IFR DECK. NE WINDS WILL BE AROUND 10 MPH TODAY...AND PICK UP A BIT TO 10-15 MPH IN THE LOWER SUSQ TONIGHT AS STORM DEEPENS TO THE EAST AND SYNOPTIC FLOW INCREASES. IMPROVING CONDITIONS ON TUES AS HIGH PRESSURE BUILDS IN. SHOULD SEE VFR CONDITIONS IN CENTRAL AND EAST...WITH MVFR CIGS IN NW FLOW UNDER SUBSIDENCE INVERSION IN THE WESTERN HIGHER TERRAIN. NORTH WIND WILL BE BREEZY...PRODUCING SPEEDS OF 10-20 MPH. OUTLOOK... WED...VFR WITH NO SIG WEATHER EXPECTED. THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM THE WEST. THU NIGHT-FRI...WIDESPREAD IFR/MVFR IN SNOW. SAT...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ004>006- 010>012-017>019-024>026-033>036-045-058-059-064>066. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ027- 028-037-041-046-049>053-056-057-063. && $$ SYNOPSIS...DEVOIR/FITZGERALD NEAR TERM...DANGELO/DEVOIR/FITZGERALD SHORT TERM...DEVOIR/FITZGERALD LONG TERM...MARTIN AVIATION...DEVOIR/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
334 PM EST MON JAN 26 2015 .SYNOPSIS... PERIODS OF LIGHT SNOW WILL DECREASE ACROSS CENTRAL PENNSYLVANIA TONIGHT AS A STRONG COASTAL STORM TRACKS TOWARDS NEW ENGLAND TONIGHT. THE COASTAL STORM WILL RAPIDLY INTENSIFY TONIGHT AND TUESDAY...AS IT TRACKS EAST OF NEW ENGLAND. HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE MIDDLE OF THE WEEK...FOLLOWED BY AN ALBERTA CLIPPER THURSDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... DEFORMATION BETWEEN THE INVERTED SFC TROF OVER WESTERN AND SOUTHWESTERN PA AND RAPIDLY DEVELOPING COASTAL LOW OFF OF SOUTHEAST VA IS MAINTAINING CATEGORICAL POPS/SNOW ACROSS THE LAURELS AND CENTRAL/WEST CENTRAL/NORTHWEST/NORTHERN MOUNTAINS PRESENTLY. MY SOUTHEAST COUNTIES HAVE STARTED TO SEE SOME LIGHT ACTIVITY BUT IT IS STILL REMOVED FROM THE BETTER DEFORMATION ASSOCIATED WITH THE INVERTED TROF TO THE WEST AND THE INTENSIFYING LOW TO THE EAST. LOWERED THE LOWER END OF SNOW FAR RANGES FOR THE EAST IN WSW...GENERALLY 2 TO 5 INCHES EXPECTED OVERALL BEFORE ACCUM SNOWFALL EXITS PA BY DAYBREAK TUE MORNING. OVERALL HOWEVER...WIDESPREAD LIGHT SNOW WILL CONTINUE TO FALL OVR CENTRAL PA THIS EVENING INTO LATE TONIGHT ALONG THE AXIS OF DEEP EASTERLY FLOW BTWN LOW TO THE SOUTH AND HIGH PRES OVR NEW ENGLAND...FORCED LOCALLY BY THE INCREASING AFOREMENTIONED DEFORMATION. HI RES NAM/HRRR/WRF ARW ALL SUPPORT AN ADDITIONAL 1-3 INCHES TODAY...WITH THE HIGHEST AMTS ACROSS THE CENTRAL MTNS/ALLEGHENIES. KEEPING HEADLINES AS IS FOR NOW BUT SOME MAY NEED TO BE EXTENDED OVERNIGHT DEPENDING UPON WHERE THE DEFORMATION PROPOGATES. HRRR INDICATES A SOUTHWEST SHIFT TO THE FORCING AFTER 03Z...AS THE PARENT COASTAL CIRCULATION DOMINATES AND TAKES OVER EFFECTIVELY DISRUPTING AND ELIMINATING THE DEFORMATION FORCING SNOWFALL OVER CENTRAL PA BY 12Z. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... AS MENTIONED ABOVE...DEFORMATION SNOW SHOWERS SHOULD DWINDLE EARLY TUESDAY...WHILE NNW FLOW IN WAKE OF DEPARTING COASTAL LOW DRAWS MUCH DRIER AIR INTO CENTRAL PA. 25 TO 35KT NE WIND GUSTS WILL BE FELT AS TIGHT PRES GRADIENT IS REALIZED IN WAKE OF STORM JUST OFFSHORE OF SOUTHERN NEW ENGLAND COAST. AS PREVIOUSLY MENTIONED...THERE IS THE POTENTIAL OF SOME BLOWING/DRIFTING...ESP EASTERN PA WHERE BUKFIT SOUNDINGS SUPPORT GUSTS BTWN 30-35KTS. ENS MEAN 925 TEMPS SUPPORT MAX TEMPS TUE FROM NR 20F OVR THE N MTNS...TO ARND 32F ACROSS THE LOWER SUSQ VALLEY. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... DEEP STORM WILL PULL AWAY FROM PA TUESDAY NIGHT. WITH WINDS FROM THE NORTH...TOOK OUT SNOW SHOWERS FOR JST. SKIES SHOULD CLEAR OUT BY WED MORNING. MAIN CHANGE WAS WED NIGHT...DID LOWER TEMPS...BASED ON 12Z MODEL RUNS...AND THAT WITH MAINLY CLEAR SKIES AND LIGHT WINDS...EXPECT TEMPS TO DROP...WITH FRESH SNOW COVER. NEXT SYSTEM WILL BRING SOME SNOW SHOWERS TO THE AREA LATER THU INTO FRIDAY. THIS SYSTEM NOT LOOKING LIKE IT WOULD RESULT IN A COASTAL REAL NEAR THE COAST. COLDER AIR FOR FRIDAY NIGHT. WEEKEND NOT LOOKING TOO BAD...COLDER AIR WILL TRY TO BUILD IN EARLY NEXT WEEK. && .AVIATION /21Z MONDAY THROUGH SATURDAY/... REDUCTIONS CONTINUE REGIONWIDE AS INVERTED TROUGH LINGERS OVER CENTRAL PA /AND AS DEVELOPING NOR`EASTER BEGINS TO DEEPEN OFF MID ATLANTIC COAST/. EXPECT WIDESPREAD LIGHT SNOW TO CONTINUE THIS INTO TONIGHT WITH VSBYS VARYING FROM 1-4SM AND CIGS OF MVFR- IFR SETTLING BACK TOWARD A MORE ROBUST IFR DECK. NE WINDS WILL BE AROUND 10 MPH TODAY...AND PICK UP A BIT TO 10-15 MPH IN THE LOWER SUSQ TONIGHT AS STORM DEEPENS TO THE EAST AND SYNOPTIC FLOW INCREASES. IMPROVING CONDITIONS ON TUES AS HIGH PRESSURE BUILDS IN. SHOULD SEE VFR CONDITIONS IN CENTRAL AND EAST...WITH MVFR CIGS IN NW FLOW UNDER SUBSIDENCE INVERSION IN THE WESTERN HIGHER TERRAIN. NORTH WIND WILL BE BREEZY...PRODUCING SPEEDS OF 10-20 MPH. OUTLOOK... WED...VFR WITH NO SIG WEATHER EXPECTED. THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM THE WEST. THU NIGHT-FRI...WIDESPREAD IFR/MVFR IN SNOW. SAT...MAINLY VFR. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ004>006- 010>012-017>019-024>026-033>036-045-058-059-064>066. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ027- 028-041-046-049>053-056-057-063. && $$ SYNOPSIS...DEVOIR/FITZGERALD NEAR TERM...DEVOIR/FITZGERALD SHORT TERM...DEVOIR/FITZGERALD LONG TERM...MARTIN AVIATION...DEVOIR/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
245 PM EST MON JAN 26 2015 .SYNOPSIS... PERIODS OF LIGHT SNOW WILL DECREASE ACROSS CENTRAL PENNSYLVANIA TONIGHT AS A STRONG COASTAL STORM TRACKS TOWARDS NEW ENGLAND TONIGHT. THE COASTAL STORM WILL RAPIDLY INTENSIFY TONIGHT AND TUESDAY...AS IT TRACKS EAST OF NEW ENGLAND. HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE MIDDLE OF THE WEEK...FOLLOWED BY AN ALBERTA CLIPPER THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... DEFORMATION BETWEEN THE INVERTED SFC TROF OVER WESTERN AND SOUTHWESTERN PA AND RAPIDLY DEVELOPING COASTAL LOW OFF OF SOUTHEAST VA IS MAINTAINING CATEGORICAL POPS/SNOW ACROSS THE LAURELS AND CENTRAL/WEST CENTRAL/NORTHWEST/NORTHERN MOUNTAINS PRESENTLY. MY SOUTHEAST COUNTIES HAVE STARTED TO SEE SOME LIGHT ACTIVITY BUT IT IS STILL REMOVED FROM THE BETTER DEFORMATION ASSOCIATED WITH THE INVERTED TROF TO THE WEST AND THE INTENSIFYING LOW TO THE EAST. LOWERED THE LOWER END OF SNOW FAR RANGES FOR THE EAST IN WSW...GENERALLY 2 TO 5 INCHES EXPECTED OVERALL BEFORE ACCUM SNOWFALL EXITS PA BY DAYBREAK TUE MORNING. OVERALL HOWEVER...WIDESPREAD LIGHT SNOW WILL CONTINUE TO FALL OVR CENTRAL PA THIS EVENING INTO LATE TONIGHT ALONG THE AXIS OF DEEP EASTERLY FLOW BTWN LOW TO THE SOUTH AND HIGH PRES OVR NEW ENGLAND...FORCED LOCALLY BY THE INCREASING AFOREMENTIONED DEFORMATION. HI RES NAM/HRRR/WRF ARW ALL SUPPORT AN ADDITIONAL 1-3 INCHES TODAY...WITH THE HIGHEST AMTS ACROSS THE CENTRAL MTNS/ALLEGHENIES. KEEPING HEADLINES AS IS FOR NOW BUT SOME MAY NEED TO BE EXTENDED OVERNIGHT DEPENDING UPON WHERE THE DEFORMATION PROPOGATES. HRRR INDICATES A SOUTHWEST SHIFT TO THE FORCING AFTER 03Z...AS THE PARENT COASTAL CIRCULATION DOMINATES AND TAKES OVER EFFECTIVELY DISRUPTING AND ELIMINATING THE DEFORMATION FORCING SNOWFALL OVER CENTRAL PA BY 12Z. && .SHORT TERM /TUESDAY/... AS MENTIONED ABOVE...DEFORMATION SNOW SHOWERS SHOULD DWINDLE EARLY TUESDAY...WHILE NNW FLOW IN WAKE OF DEPARTING COASTAL LOW DRAWS MUCH DRIER AIR INTO CENTRAL PA. 25 TO 35KT NE WIND GUSTS WILL BE FELT AS TIGHT PRES GRADIENT IS REALIZED IN WAKE OF STORM JUST OFFSHORE OF SOUTHERN NEW ENGLAND COAST. AS PREVIOUSLY MENTIONED...THERE IS THE POTENTIAL OF SOME BLOWING/DRIFTING...ESP EASTERN PA WHERE BUKFIT SOUNDINGS SUPPORT GUSTS BTWN 30-35KTS. ENS MEAN 925 TEMPS SUPPORT MAX TEMPS TUE FROM NR 20F OVR THE N MTNS...TO ARND 32F ACROSS THE LOWER SUSQ VALLEY. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... FAIR AND CHILLY WED EXPECTED WED...AS HIGH PRES BUILDS OVR THE AREA. MED RANGE GUIDANCE STILL INDICATES A CHANCE OF SNOW THURS/THU NIGHT WITH NEXT IN SERIES OF CLIPPERS. BULK OF MED RANGE GUIDANCE TRACKS THE SFC LOW NORTH OF PA...LIKELY RESULTING IN MINIMAL ACCUMS ACROSS OUR AREA. ECENS SHOWS A DEEPENING UPPER LVL TROF OVR THE EASTERN CONUS BY NEXT WEEKEND...OFFERING NO RESPITE FROM THE COLD WX. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... REDUCTIONS CONTINUE REGIONWIDE AS INVERTED TROUGH LINGERS OVER CENTRAL PA /AND AS DEVELOPING NOR`EASTER BEGINS TO DEEPEN OFF MID ATLANTIC COAST/. EXPECT WIDESPREAD LIGHT SNOW TO CONTINUE THIS INTO TONIGHT WITH VSBYS VARYING FROM 1-4SM AND CIGS OF MVFR- IFR SETTLING BACK TOWARD A MORE ROBUST IFR DECK. NE WINDS WILL BE AROUND 10 MPH TODAY...AND PICK UP A BIT TO 10-15 MPH IN THE LOWER SUSQ TONIGHT AS STORM DEEPENS TO THE EAST AND SYNOPTIC FLOW INCREASES. IMPROVING CONDITIONS ON TUES AS HIGH PRESSURE BUILDS IN. SHOULD SEE VFR CONDITIONS IN CENTRAL AND EAST...WITH MVFR CIGS IN NW FLOW UNDER SUBSIDENCE INVERSION IN THE WESTERN HIGHER TERRAIN. NORTH WIND WILL BE BREEZY...PRODUCING SPEEDS OF 10-20 MPH. OUTLOOK... TUE...AREAS MVFR IN SHSN WEST...GENERALLY VFR EAST. BREEZY N WIND. WED...VFR WITH NO SIG WEATHER EXPECTED. THU...VFR TO START...WITH LATE DAY RESTRICTIONS SPREADING IN FROM THE WEST. THU NIGHT-FRI...WIDESPREAD IFR/MVFR IN SNOW. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 7 AM EST TUESDAY FOR PAZ004>006- 010>012-017>019-024>026-033>036-045-058-059-064>066. WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ027- 028-041-046-049>053-056-057-063. && $$ SYNOPSIS...DEVOIR NEAR TERM...DEVOIR SHORT TERM...DEVOIR LONG TERM...FITZGERALD/MARTIN AVIATION...DEVOIR/MARTIN/RXR
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
328 AM CST MON JAN 26 2015 .DISCUSSION... CURRENTLY...CLOUDY SKIES ACROSS THE MIDSOUTH WITH TEMPS DROPPING INTO THE 30S UNDER NW WINDS AT 10 TO 20 MPH WITH HIGHER GUSTS. TODAY...THE POTENT UPPER TROF THAT WILL SOON HELP CREATE THE NORTHEAST U.S. BLIZZARD IS PUSHING TOWARD THE EASTERN SEABOARD AND AWAY FROM THE MIDSOUTH. A QUICK MOVING SURFACE RIDGE OF HIGH PRESSURE SANDWICHED BETWEEN THIS DEPARTING SYSTEM AND ANOTHER WEAK SURFACE LOW DEVELOPING OVER THE MID MISSISSIPPI VALLEY WILL PUSH THROUGH TODAY. WINDS WILL SHIFT FROM NORTH THIS AFTERNOON TO SOUTHWEST BY THIS EVENING. AS A RESULT OF THIS WIND SHIFT EXPECT LOW CLOUDS TO CLEAR OUT DURING THE DAY...LINGERING THE LONGEST ACROSS NORTHEAST SECTIONS OF WEST TENNESSEE. TEMPS WILL BE COOL ESPECIALLY ACROSS THE EAST... ALONG THE TN RIVER...WHERE LOWER 40S IS ABOUT THE LIMIT...TEMPS WILL HIT 50 ACROSS PARTS OF EAST ARKANSAS WHERE SUNSHINE WILL BE MORE PLENTIFUL. TONIGHT...A WEAK SURFACE LOW WILL DROP INTO WESTERN MIDDLE TENNESSEE AFTER MIDNIGHT AND PUSH A WEAK COLD FRONT THROUGH THE AREA. THIS WILL SERVE TO SWITCH THE SURFACE WINDS BACK AROUND TO THE NORTH. WINDS WILL PROBABLY BE A LITTLE GUSTY BY MORNING AND WILL KEEP THE AIRMASS MIXED. AS A RESULT LOWS WILL ONLY BE ABLE TO DROP INTO THE MID AND UPPER 30S. TUESDAY AND TUESDAY NIGHT...BEHIND THE QUICK MOVING SURFACE LOW AND COLD FRONT EXPECT GUSTY NORTH WINDS AND SOME ADDITIONAL LOW CLOUDS TO MOVE BACK IN ESPECIALLY NEAR THE TN RIVER. THE MAV AND MET ARE QUITE A BIT COOLER THAN THE PREVIOUS FORECAST AND HAVE HAD TO CUT TEMPS ACROSS MUCH OF THE AREA. HIGHS WILL RANGE FROM THE MID 40S NEAR PARIS...WHERE CLOUDS WILL LINGER MUCH OF THE DAY TO THE MID 50S ACROSS SW PORTIONS OF THE FORECAST AREA. MOSTLY CLEAR SKIES AND LIGHT WINDS WILL ALLOW TEMPS TO DROP INTO THE UPPER 20S AND LOWER 30S TUESDAY NIGHT. WEDNESDAY THROUGH FRIDAY...NICE DAY ON TAP FOR WEDNESDAY AS UPPER FLOW TURNS MORE ZONAL AND SOUTHWEST SURFACE WINDS DEVELOP AHEAD AN APPROACHING COLD FRONT. TEMPS WILL CLIMB INTO THE 50S JUST ABOUT EVERYWHERE. THE MOISTURE STARVED FRONT WILL PUSH THROUGH LATE WEDNESDAY NIGHT AND THURSDAY WITH ONLY SLIGHT CHANCE OF SHOWERS ACROSS EASTERN SECTIONS. WEDNESDAY NIGHT WILL BE MILD UNDER PERSISTENT SOUTHERLY FLOW AND HIGHS ON THURSDAY WILL REACH WELL INTO THE 50S BEFORE THE COOLER AIR MOVES IN. COOL HIGH PRESSURE SETTLES IN FOR FRIDAY WITH HIGHS BACK IN THE 40S. SATURDAY AND SUNDAY...POTENTIAL OVERRUNNING SITUATION SETS UP WITH DEVELOPING WSW FLOW ALOFT OVER A COOL AIRMASS AT THE SURFACE. MODELS TIMING AND CONSISTENCY ARE NOT GREAT AT THIS POINT. GFS IS FASTER...ECMWF IS SLOWER. WILL COMPROMISE WITH LOW POPS THROUGH THE WEEKEND AND BELOW NORMAL TEMPS. SJM && .AVIATION... 06Z TAFS MVFR WILL PREVAIL AREAWIDE DURING THE OVERNIGHT. THE BACKSIDE OF THE STRATUS DECK HAD PASSED THROUGH MCI AT 05Z. THE 02Z HRRR MODEL SHOWED IFR CONTINUING OVERNIGHT OVER CENTRAL MO...WHILE BREAKING UP MVFR CIGS OVER NORTHEAST AR BY DAYBREAK. VFR AND RELAXING/BACKING WINDS WILL PREVAIL AREAWIDE ON MONDAY. PWB && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1139 PM CST SUN JAN 25 2015 .UPDATE... UPDATED FOR 06Z AVIATION DISCUSSION. && .PREV DISCUSSION... /ISSUED 839 PM CST SUN JAN 25 2015/ UPDATE... UPDATED THIS EVENING TO FINE-TUNE POPS AND ALSO BETTER TIME THE EXIT OF PRECIP TONIGHT. ELECTED TO ADD LIKELY POPS ACROSS PORTIONS OF MIDDLE TENNESSEE CLOSER TO THE VORT MAX ROTATING SOUTHEAST. A BAND OF WIDESPREAD SHOWERS WAS MOVING SOUTHEAST AND WILL AFFECT THE REGION THROUGH MIDNIGHT. ELSEWHERE...MAINTAINED SLIGHT CHANCE TO CHANCE POPS TO ACCOUNT FOR REMNANT SHOWERS MORE ASSOCIATED WITH DAYTIME HEATING AND THE (VERY) COLD POCKET NEAR 500 MB. THESE WILL CONTINUE TO WANE THROUGH THE EVENING. OTHERWISE...FORECAST LOOKS GOOD WITH A WARM-UP SCHEDULED THROUGH MID-WEEK. TVT PREV DISCUSSION... /ISSUED 534 PM CST SUN JAN 25 2015/ UPDATE... UPDATED FOR 00Z AVIATION DISCUSSION BELOW. PREV DISCUSSION... /ISSUED 309 PM CST SUN JAN 25 2015/ DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILES THIS AFTERNOON PLACE A CLOSED UPPER LEVEL LOW OVER SOUTHERN ILLINOIS THIS AFTERNOON. A SHORTWAVE ROTATING AROUND THE UPPER LEVEL LOW IS PRODUCING RAIN SHOWERS ACROSS THE MID SOUTH THIS AFTERNOON. AS OF 2 PM CST...TEMPERATURES ARE IN THE 50S AT MOST LOCATIONS. SHORT TERM...(TONIGHT THROUGH WEDNESDAY)...AN UPPER LEVEL LOW OVER SOUTHERN ILLINOIS WILL GRADUALLY MOVE TO THE APPALACHIANS BY MONDAY AND THE MID ATLANTIC COAST BY MONDAY NIGHT. LATEST SHORT TERM MODEL TRENDS SUGGEST CHANCES FOR RAIN SHOWERS WILL PERSIST ACROSS THE MID SOUTH THIS EVENING AS ANOTHER SHORTWAVE TROUGH ROTATING AROUND THE UPPER LEVEL LOW ROTATES THROUGH THE LOWER MISSISSIPPI VALLEY. AT THIS TIME...IT APPEARS THAT PRECIPITATION SHOULD BE OUT OF THE FORECAST AREA AROUND/AFTER 06Z...AND HAVE LEFT THE REMAINDER OF TONIGHT/S FORECAST PRECIPITATION FREE. SURFACE AND UPPER LEVEL RIDGING WILL BUILD BACK IN ACROSS THE MID SOUTH FOR MONDAY THROUGH WEDNESDAY. TEMPERATURES THROUGH THE SHORT TERM WILL AVERAGE NEAR NORMAL THROUGH MUCH OF THE PERIOD. LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)...LONG TERM MODELS INDICATE ANOTHER COLD FRONT WILL MOVE THROUGH THE LOWER MISSISSIPPI VALLEY ON THURSDAY. QUESTIONS REMAIN WITH THE AMOUNT OF MOISTURE WITH THIS SYSTEM AND HAVE KEPT CHANCES ON THE LOW END FOR NOW. CJC && .AVIATION... 06Z TAFS MVFR WILL PREVAIL AREAWIDE DURING THE OVERNIGHT. THE BACKSIDE OF THE STRATUS DECK HAD PASSED THROUGH MCI AT 05Z. THE 02Z HRRR MODEL SHOWED IFR CONTINUING OVERNIGHT OVER CENTRAL MO...WHILE BREAKING UP MVFR CIGS OVER NORTHEAST AR BY DAYBREAK. VFR AND RELAXING/BACKING WINDS WILL PREVAIL AREAWIDE ON MONDAY. PWB && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1126 PM CST SUN JAN 25 2015 .DISCUSSION... SEE 06Z AVIATION DISCUSSION. && .AVIATION... VFR CONDS TO PREVAIL FOR THE NEXT 24 HOURS. LLWS WILL BE POSSIBLE THROUGH EARLY MONDAY AS THE NAM12 AND RAP CONTINUE TO SHOW 40-45 KNOTS AT 925 MB. 43 && .PREV DISCUSSION... /ISSUED 910 PM CST SUN JAN 25 2015/ UPDATE... CURRENT FORECAST REMAINS ON TRACK AS HIGH CLOUDS DRIFT ACROSS THE AREA WITH ONLY MINOR TWEAKS MADE TO HOURLY TEMPERATURES AND DEW POINTS BASED ON LATEST OBSERVATIONS. WEST TO NORTHWEST WINDS BEHIND TODAY/S COLD FRONT WILL HELP DRIER AIR FILTER INTO THE AREA...ALLOWING LOW TEMPERATURES TO FALL INTO THE UPPER 30S TO MID 40S. HUFFMAN PREV DISCUSSION... /ISSUED 300 PM CST SUN JAN 25 2015/ DISCUSSION... VIS SATELLITE SHOWS SOME NICE CIRRUS STREAMING OVER SE TX THIS AFTERNOON. A DRY COLD FRONT PUSHED THROUGH THE AREA SHIFTING WINDS TO THE NW AND REALLY THATS ABOUT IT. GIVEN NW WINDS...TEMPS HAVE REACHED CLOSE TO 70 AS COLD ADVECTION LAGS. MOSTLY CLEAR SKIES AND DRY AIRMASS SHOULD ALLOW FOR MIN TEMPS BACK IN THE UPPER 30S/LOW 40S FOR MON MORNING. MAX TEMPS TOMORROW WILL BE SLIGHTLY COOLER BUT A NICE WARM UP WILL BE ON TAP FOR THE NEXT FEW DAYS. POTENT SHORT WAVE TROUGH OVER MISS/TN RIVER VALLEYS ON WATER VAPOR IMAGERY WILL QUICKLY MOVE EAST INTO THE MID ATLANTIC. THE SYSTEM SHOULD BOMB OUT WITH DEEPENING LOW PRESSURE AND BLIZZARD CONDITIONS LATE MON THROUGH WED. HOW DOES THIS IMPACT HOUSTON? LETS JUST SAY YOU SHOULD NOT EXPECT TO FLY EAST ANY TIME SOON ESPECIALLY JFK/LGA/BOS. WHILE THERE SHOULD NOT BE ANY DELAYS AT IAH/HOU THERE MAY BE SOME TRICKLE DOWN TRAVEL IMPACTS. OVERALL UPPER LEVEL PATTERN REMAINS AMPLIFIED THROUGH THE END OF THE WEEK WITH RIDGING OVER THE WESTERN THIRD OF THE U.S. AND NW FLOW/LONG WAVE TROUGH OVER THE EASTERN 2 THIRDS OF THE U.S. BY THE END OF THE WEEK...GFS/ECMWF DEVELOP ANOTHER UPPER LOW OVER S CALIFORNIA AND BAJA PENINSULA. THIS SEEMS TO BE A FAVORED REGION FOR CUT OFF LOWS THIS YEAR. THE PATTERN LOOKS VERY SIMILAR TO THE RECENT RAIN EVENT AND THEN RUN OF GOOD WEATHER AFTER THAT. GRANTED IT IS NEXT WEEKEND BUT WE WILL CONTINUE TO SHOW 30-50 PERCENT RAIN CHANCES STARTING SAT INTO SUN. A COLD FRONT WILL PUSH INTO THE AREA THUR INTO FRI SO THERE SHOULD BE ANOTHER SET UP FOR GOOD COLD RAIN. THE HARDEST PART WILL BE TIMING ANY WEAK SHORT WAVE TROUGHS THAT PUSH THROUGH IN THE MAIN JET FLOW. GFS/ECMWF HAVE SOME DIFFERENCES IN THAT REGARD. GFS IS WET AT FIRST BUT REALLY HANGS THE CUTT OFF OUT OVER THE BAJA. ECMWF IS DRIER AT FIRST...HAS ONE CLUSTER OF RAIN NEXT SUN AND THEN FINALLY EJECTS THE UPPER LOW OVER THE AREA FOR ANOTHER GOOD SOAKER IN THE 8-10DAY RANGE. WITH THAT IN MIND...STANDARD DISCLAIMER APPLIES...DETAILS OF THE 8-10 DAY FORECAST WILL CHANGE QUITE A BIT WITH FUTURE MODEL RUNS. STILL SOMETHING TO MONITOR. 39 MARINE... W/SWLY WINDS JUST A BIT STRONGER THAN PREVIOUSLY EXPECTED FOR THIS AFTN...ESPECIALLY FOR THE OFFSHORE WATERS. THIS TIGHTENED GRADIENT WILL LIKELY RELAX A BIT THIS EVE AS THE WEAK SFC BOUNDARY MOVES IN FROM THE N/NW. NO REAL CHANGE FROM CURRENT FCST OF SCEC CONDITIONS TONIGHT/EARLY MON. HIGH PRESSURE BUILDING BACK INTO THE REGION BE- HIND THE FRONT WILL HELP TO DECREASE WINDS/SEAS BY MON AFTN/EVE IF ALL GOES WELL. THE GENERALLY LIGHT WLY FLOW MON SHOULD GIVE WAY TO GENERALLY LIGHT ONSHORE WINDS FOR TUES/WEDS. THE NEXT FRONT ON TAP FOR LATE THURS. 41 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 42 66 48 73 50 / 0 0 0 0 0 HOUSTON (IAH) 43 65 47 74 47 / 0 0 0 0 0 GALVESTON (GLS) 47 60 51 66 54 / 0 0 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 9 AM CST MONDAY FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH MONDAY MORNING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
528 PM CST TUE JAN 27 2015 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND WEDNESDAY ISSUED AT 258 PM CST TUE JAN 27 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH PRESSURE NOSING SOUTHWEST ACROSS THE UPPER PENINSULA AND THE STATE OF WISCONSIN. BUT DESPITE THE RIDGE AXIS SHARPENING OVER NE WISCONSIN...LOW STRATUS HAS BEEN AWFULLY DIFFICULT TO ERODE THIS AFTERNOON. CLOUDS OVER NORTHERN LAKE MICHIGAN ARE VERY SLOWLY ERODING FROM EAST TO WEST...AND AS BOUNDARY LAYER FLOW LIGHTENS AND BACKS TO THE NORTH LATER THIS AFTERNOON...THINK THIS WILL ACCELERATE CLEARING OVER THE FOX VALLEY AND LAKESHORE. OTHERWISE...OVERCAST CONDITIONS TO REMAIN OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. LOOKING UPSTREAM...CLOUDS ARE INCREASING AGAIN OVER THE NORTHERN PLAINS AND NORTHWEST LAKE SUPERIOR AHEAD OF THE NEXT CLIPPER SYSTEM WHICH WILL ARRIVE WEDNESDAY NIGHT. IN THE MEANTIME...CLOUD AND TEMP TRENDS ARE THE MAIN FORECAST CONCERNS. TONIGHT...ARCTIC HIGH PRESSURE WILL TEMPORARILY BUILD ACROSS EASTERN WISCONSIN THIS EVENING THEN RETREAT BACK EAST OVERNIGHT. STILL ANTICIPATING AT LEAST PARTIAL CLEARING TAKING PLACE OVER THE FOX VALLEY AND LAKE SHORE AS THE RIDGE AXIS MOVES INTO THAT AREA. FARTHER WEST...WINDS WILL TURN TO THE SOUTH OR SOUTHWEST...AND TRENDS OVER THE U.P. SUPPORT THAT CLOUDS WILL JUST ROTATE NORTHWARD...LEAVING A LOW OVERCAST DECK IN PLACE. AS A RESULT...INCREASED SKY COVER. THEN OVERNIGHT...MID AND HIGH CLOUDS WILL BE RETURNING FROM THE NORTHWEST...AND ANY CLEARING OVER EASTERN WISCONSIN SHOULD GO BACK TO BROKEN OR OVERCAST. TRENDED WARMER WITH LOW TEMPS DUE TO THE PERSISTENT CLOUD COVER. WEDNESDAY...LOW PRESSURE WILL BE MOVING INTO THE NORTHERN MISSISSIPPI VALLEY DURING THE AFTERNOON. AS WINDS BACK TO THE SOUTHEAST...WARMER LOW LEVEL AIR WILL FINALLY SURGE INTO CENTRAL AND NORTHEAST WISCONSIN...WHICH SHOULD ERODE ANY REMAINING LOW OVERCAST. HOWEVER...WILL STILL HAVE AMPLE MID AND UPPER CLOUDS OVERHEAD...MAKING FOR A MOSTLY CLOUDY DAY. AN 850MB WARM FRONT WILL BE MAKING INTO NORTH-CENTRAL AND CENTRAL WISCONSIN BY LATE IN THE AFTERNOON...BUT PROGGED SOUNDINGS CONTINUE TO SHOW A WEDGE OF DRY AIR AROUND 10KFT THAT SHOULD BE ENOUGH TO KEEP THE AREA DRY. HIGHS WARMING INTO THE LOW TO MID 30S. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY ISSUED AT 258 PM CST TUE JAN 27 2015 NORTHWEST UPPER FLOW WILL CONTINUE THROUGH THE PERIOD...SO IT WILL BE GENERALLY COLD AND DRY. THERE ARE AT LEAST TWO OPPORTUNITIES FOR SOME SNOW. THE FIRST IS TOMORROW NIGHT AND EARLY THURSDAY AS JET ENERGY APPROACHES FROM THE WEST. THERE ISN/T MUCH MOISTURE AVAILABLE UNTIL THE SYSTEM GETS EAST OF WISCONSIN. THEREFORE SNOW SHOULD BE LIGHT AND MIGHT BEGIN AS SLEET ACROSS THE CENTRAL AND EAST CENTRAL AREAS. THERE IS ANOTHER CHANCE OF SNOW SATURDAY NIGHT AND SUNDAY AHEAD OF ARCTIC AIR. THE GFS AND ECMWF HAVE A FEW WAVES OF LOW PRESSURE THAT MOVE NORTHEAST ALONG THE FRONT...RESULTING IN LOTS OF DIFFERENCES IN TIMING AND SNOW AMOUNTS. MILD PACIFIC AIR WILL BRING US WARMER THAN NORMAL TEMPERATURES THURSDAY THEN BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH THE MIDDLE OF NEXT WEEK. THERE. WIND CHILL ADVISORIES MAY BE NEEDED MONDAY. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 526 PM CST TUE JAN 27 2015 LOOKS LIKE WE/VE MISSED OUT ON OUR OPPORTUNITY TO GET RID OF THE LOW CLDS. THEY ARE NOW FIRMLY IN PLACE ACRS THE ENTIRE FCST AREA...TRAPPED BY THE WK FLOW WITHIN THE LOW-LEVEL RIDGE. EXPECT CIGS AND VSBYS TO GRADUALLY COME DOWN OVERNIGHT...WITH IMPROVEMENT NOT OCCURRING UNTIL MID-DAY OR AFTN TOMORROW. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......RDM AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
459 PM CST MON JAN 26 2015 .UPDATE... ISSUED AT 459 PM CST MON JAN 26 2015 HAVE EXPANDED THE ADVISORY INTO FAR SOUTHWEST WISCONSIN WHERE NUMEROUS REPORTS OF BAD ROADS HAVE BEEN RECEIVED...ESPECIALLY SECONDARY ROADS. ALSO HAVE EXTENDED THE ADVISORY UNTIL MIDNIGHT. A WARM FRONT SITS ALONG THE MISSISSIPPI RIVER...WHICH APPEARS TO BE STUCK NOW THAT ITS PARALLEL WITH THE UPPER LEVEL FLOW. ADDITIONALLY...A SURFACE LOW OVER NORTHWEST WI WILL RIDE DOWN ALONG THIS FRONT...SETTING UP AN INVERTED TROUGH IN ITS WAKE. LOW LEVEL VERTICAL MOTION SHOULD PERSIST ALONG AND EAST OF THIS BOUNDARY...AND WITH TEMPERATURES IN THIS ZONE BELOW FREEZING...WE SHOULD SEE A CONTINUATION OF FREEZING DRIZZLE THROUGH THE EVENING. THIS IS SHOWN NICELY IN THE LATEST HRRR RUNS...RAP...26.12Z REGIONAL CANADIAN AND 26.18Z NAM. ANOTHER CONCERN IS THE MASS OF SNOW MARCHING SOUTH OUT OF NORTHWEST WISCONSIN...WHICH SHOULD MARCH DOWN THROUGH CENTRAL WI OVER THE NEXT FEW HOURS. THE COMBINATION OF THIS SNOW AND FREEZING DRIZZLE WARRANTS A CONTINUATION OF THE ADVISORY. LUCKILY IMPACTS SHOULD CONTINUE TO DECREASE AS ROADS CONTINUE TO BE TREATED...THOUGH THE LOSS OF DAYTIME HEATING WILL ALLOW UNTREATED ROADS TO COOL AND MAKE THINGS WORSE. && .SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT) ISSUED AT 331 PM CST MON JAN 26 2015 MAIN FORECAST PROBLEM WILL BE LINGERING FREEZING DRIZZLE CHANCES THROUGH THIS EVENING. SURFACE MAP THIS AFTERNOON HAS SURFACE LOW OVER THE ARROWHEAD WITH A WARM FRONT EXTENDING ACROSS EASTERN MN/IA. TEMPERATURES RANGED FROM THE MIDDLE 30S TO MIDDLE 40S BEHIND THE FRONT ACROSS SOUTHEAST MN/NORTHEAST IA...TO THE LOWER TO MIDDLE 20S EAST OF THE MISSISSIPPI RIVER/AHEAD OF THE FRONT. LOWER LEVEL ISENTROPIC LIFT ACROSS THIS FRONT WAS PRODUCING AREAS OF FREEZING DRIZZLE EAST OF THE MISSISSIPPI WITH REPORTS OF SOME SLIPPERY STRETCHES ON ROADWAYS VIA WI 511 AND FROM LOCAL ROAD CREW. LOOK FOR THE SURFACE LOW TO MOVE SOUTHEAST FROM THE ARROWHEAD OF MN THIS AFTERNOON INTO NORTHWEST IL BY EARLY THIS EVENING. MAIN LIFT AHEAD OF THIS LOW ...WHICH IS PRESENTLY CAUSING THE FREEZING DRIZZLE WILL THEREFORE BE IN A WANING PHASE WITH ITS PASSAGE. HOWEVER...RAP BUFKIT SOUNDING SHOWS SOME LINGERING LIFT ACROSS CENTRAL WI THROUGH LATER THIS EVENING AS THE MID-LEVEL/SURFACE INVERTED TROUGH HANGS UP. WILL THEREFORE CONTINUE TO CARRY FREEZING DRIZZLE MENTION INTO THIS EVENING. THERE MAY BE SOME LIGHT SNOW AS WELL WITH POCKETS OF FEEDER/SEEDER ICE. MAY HAVE TO EXTEND CURRENT ADVISORY A LITTLE LONGER INTO THIS EVENING TO COVER FOR THIS. WILL KEEP A CLOSE EYE ON IT. HIGH PRESSURE BUILDS OVER THE AREA LATER TONIGHT THROUGH TUESDAY FOR QUIET WEATHER. LOOKS LIKE IT WILL REMAIN MOSTLY CLOUDY THOUGH DESPITE HIGH BUILDING IN DUE TO MOISTURE BEING TRAPPED UNDER THE SUBSIDENCE INVERSION. WITH PARTIAL SUNSHINE LATE IN THE MORNING THROUGH THE AFTERNOON...PLAN ON HIGHS REBOUNDING INTO THE 30S. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 331 PM CST MON JAN 26 2015 UNSEASONABLY MILD CONDITIONS EXPECTED FOR WEDNESDAY AHEAD OF APPROACHING LOW PRESSURE ACROSS THE PLAINS. DESPITE AN INCREASE IN STRATUS CLOUD...LOOK FOR HIGHS WELL INTO THE 30S WITH POSSIBLY A FEW LOWER 40 READINGS ACROSS PARTS OF NORTHEAST IA INTO FAR SOUTHWEST WI. A WINTRY MIX LOOKS TO IMPACT THE AREA WEDNESDAY NIGHT INTO THURSDAY MORNING AS THE LOW OVER THE PLAINS MOVES TOWARD THE GREAT LAKES REGION. MODEL SOUNDINGS NOT SHOWING A LOT OF ICE IN CLOUD FOR SNOW PRODUCTION...SO LOOKS LIKE MORE OF A FREEZING RAIN/DRIZZLE POTENTIAL AS A RESULT. WILL CONTINUE TO MONITOR THIS. LATEST GFS/ECMWF SHOW ANOTHER STORM SYSTEM MOVING OUT OF THE PLAINS TOWARD THE UPPER MISSISSIPPI RIVER REGION SATURDAY AFTERNOON INTO SUNDAY FOR SNOW CHANCES. OTHERWISE...LOOKS LIKE A SIGNIFICANT COOL DOWN THROUGH THE WEEKEND/EARLY NEXT WEEK AS PATTERN SHIFTS TO NORTHWEST FLOW ALOFT. HIGHS ON SATURDAY EXPECTED TO BE IN THE 20S...COOLING INTO THE SINGLE DIGITS/TEENS BY MONDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1142 AM CST MON JAN 26 2015 LIGHT FREEZING DRIZZLE WILL IMPACT KLSE AT TIMES THIS AFTERNOON AND COULD POSSIBLY CONTINUE INTO EARLY THIS EVENING. TEMPERATURES MAY WARM ENOUGH FOR THE PRECIPITATION TO FALL AS DRIZZLE AT THE SURFACE LATE THIS AFTERNOON. WINDS WILL SWITCH TO THE WEST THEN TO THE NORTHWEST THIS AFTERNOON AS A WARM FRONT EDGES IN. PLAN ON MVFR CONDITIONS WITH IFR CONDITIONS POSSIBLE AT TIMES AT KLSE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ017- 029-032>034-041>044-053>055-061. MN...NONE. IA...NONE. && $$ UPDATE...AJ SHORT TERM...DAS LONG TERM....DAS AVIATION...WETENKAMP
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 245 PM CST MON JAN 26 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A WEAKENING LOW PRESSURE SYSTEM MOVING SSE AS IT APPROACHES FAR NORTHWEST WISCONSIN. AHEAD OF THE LOW...MODEST WARM ADVECTION AND MID-LEVEL FGEN ARE CONTRIBUTING TO A BAND OF SNOW...BUT THE BEST RETURNS APPEAR TO BE EXITING CENTRAL WISCONSIN EARLY THIS AFTERNOON. THE LATEST DATA SHOW THAT THE MID-LEVEL FGEN WILL CONTINUE TO WEAKEN AS THE BEST WARM ADVECTION PULLS OUT...SO SHOULD SEE ONLY VERY LIGHT SNOW OR FLURRIES FOR A PERIOD UNTIL BETTER RETURNS OVER WESTERN LAKE SUPERIOR ARRIVE. STILL SEEING OBSERVATIONS AT MARSHFIELD AND MEDFORD OF FREEZING DRIZZLE OR UNKNOWN PRECIP...SO NO PLANS TO CHANGE THE ADVISORY. SOME POSSIBILITY THAT IT COULD GET EXTENDED INTO THE EVENING...BUT NO INDICATIONS OF FREEZING DRIZZLE ELSEWHERE THOUGH. SNOWFALL ACCUMS AND IMPACTS REMAIN THE MAIN FORECAST CONCERNS. TONIGHT...CLIPPER LOW PRESSURE WILL CONTINUE TO WEAKEN AS IT TRACKS ACROSS FAR SW WISCONSIN EARLY THIS EVENING AND INTO WESTERN ILLINOIS. ANOTHER AREA OF LIGHT SNOW ASSOCIATED WITH WARM ADVECTION WILL MOVE ACROSS NORTH-CENTRAL AND EASTERN WISCONSIN THAT WILL PROLONG THE LIGHT SNOW FOR MUCH OF THE EVENING. THE SNOW WILL LIKELY DIMINISH OVER CENTRAL WISCONSIN BY MID TO LATE EVENING...BUT SATURATION WILL REMAIN DEEP ENOUGH FOR PATCHY FREEZING DRIZZLE...SO LEFT THAT POSSIBILITY IN THE FORECAST ON THE WESTERN EDGE OF THE PRECIP. THE HIGHEST ACCUMULATIONS WILL BE OVER EASTERN WISCONSIN WHERE A HALF INCH OR INCH WILL LIKELY FALL. LIGHT ONSHORE FLOW FROM SE WINDS MAY LOCALLY BOOST TOTALS HIGHER OVER THE DOOR PENINSULA FROM LAKE ENHANCEMENT. MOST GUIDANCE SUPPORTS LIGHT PRECIP DIMINISHING LATE TONIGHT ACROSS THE EAST...THOUGH FLURRIES COULD CONTINUE IN THE EAST DUE TO THE LIGHT ONSHORE FLOW. LOWS MAINLY BETWEEN 19-24 DEGREES. TUESDAY...BECAUSE WEAK LOW LEVEL CONVERGENCE WILL BE CONTINUING...THINK OVERCAST CONDITIONS WILL PERSIST THROUGH MUCH OF THE MORNING HOURS. AS ARCTIC HIGH PRESSURE TRIES TO REBUILD INTO THE REGION DURING THE AFTERNOON...SHOULD SEE THE LOW OVERCAST ERODE FROM THE WEST AND ALSO THE EAST WHICH WILL LEAD TO INCREASING SUNSHINE. HIGHS WILL RANGE FROM THE UPPER 20S TO LOWER 30S. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 245 PM CST MON JAN 26 2015 A COUPLE OF WEAK UPPER TROUGHS WILL APPROACH FROM THE WEST WEDNESDAY NIGHT AND BRING SOME LIGHT SNOW TO THE REGION. NOT MUCH MOISTURE AVAILABLE BUT THERE IS PRETTY GOOD LOW LEVEL WARM ADVECTION AND CONVERGENCE IN NORTHEAST WISCONSIN. THINK WE WILL GET 1 TO 3 INCHES WITH THE GREATEST AMOUNTS OVER DOOR MARINETTE AND FLORENCE AND FOREST COUNTIES. LAKE EFFECT SNOW SHOWERS POSSIBLE IN NORTHCENTRAL WISCONSIN WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT BUT ACCUMULATIONS SHOULD BE LIGHT. DRY AND COLDER FRIDAY AND SATURDAY. AN ARCTIC COLD FRONT WILL APPROACH THE AREA SATURDAY NIGHT AND SUNDAY AND SHOULD BE ABLE TO PRODUCE SOME LIGHT SNOW AS IT MOVES ACROSS THE AREA. MONDAY SHOULD BE QUITE COLD WITH SUBZERO HIGHS POSSIBLE IN NORTHERN WISCONSIN. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1124 AM CST MON JAN 26 2015 CLIPPER SYSTEM WILL BE MOVING SOUTH ACROSS THE REGION THROUGH TONIGHT. LIGHT SNOW...DROPPING VSBYS TO MAINLY IFR...LOCALLY LIFR...WILL SPREAD EAST INTO EASTERN WISCONSIN THIS AFTERNOON. PATCHY FZDZ MAY IMPACT CENTRAL AND NORTH-CENTRAL WISCONSIN AT TIMES THROUGH TONIGHT...BUT HIGHER IMPACTS SHOULD RESIDE WEST OF THIS AREA. TOTAL ACCUMULATIONS WILL MOSTLY FALL INTO THE 1-2 INCH RANGE...LOCALLY HIGHER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. THE SNOW AND SPOTTY FREEZING DRIZZLE WILL GRADUALLY BE DIMINISHING LATE THIS EVENING INTO THE OVERNIGHT. PLENTY OF LOW CIGS UPSTREAM...SO THINK SKIES WILL REMAIN IFR/MVFR OVERCAST THROUGH MUCH OF TUESDAY MORNING. MPC. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ035. && $$ SHORT TERM.....MPC LONG TERM......RDM AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 PM CST SUN JAN 25 2015 .UPDATE... ISSUED AT 831 PM CST SUN JAN 25 2015 AFTER MUCH DELIBERATION...HAVE DECIDED TO ISSUE THE WINTER WEATHER ADVISORY FOR SOME OF THE FORECAST AREA. THE COUNTIES ALONG THE MISSISSIPPI RIVER HAVE THE HIGHEST CONFIDENCE OF SEEING A COUPLE HUNDREDTHS OF FREEZING DRIZZLE AS THE SNOW ENDS...WHILE IN TAYLOR/CLARK COUNTIES THE POTENTIAL EXISTS FOR A LITTLE MORE SNOW TO FALL THAN WHATS EVEN CURRENTLY FORECAST. THATS BECAUSE THE RAP CONTINUES TO SHOW 7 C/KM LAPSE RATES MARCHING THROUGH WESTERN WISCONSIN MONDAY MORNING...WHICH SHOULD ADD SOME CONVECTIVE ENHANCEMENT TO THE SNOWFALL. THE EXPERIMENTAL HRRR AT BOULDER ALSO SHOWS THIS CONVECTIVE ENHANCEMENT...EVEN INTO SOUTHEAST MN AND INTO THE LSE AREA...RIGHT AT MORNING COMMUTE TIME. ALTHOUGH SNOWFALL AMOUNTS WILL NOT REACH ADVISORY CRITERIA ALONE...THE COMBINATION OF THE SNOW AND FREEZING DRIZZLE SHOULD MAKE FOR A MESS ON ROADWAYS...ESPECIALLY THOSE LEFT UNTREATED. ADDITIONALLY...HAVING THIS PRECIPITATION COME THROUGH AT MORNING COMMUTE TIME IS ALSO A PROBLEM. THESE ARE THE MAIN REASONS WHY THE ADVISORY HAS BEEN ISSUED. UPDATE ISSUED AT 541 PM CST SUN JAN 25 2015 FOLLOWING THE SITUATION CLOSELY FOR MONDAY AS A WINTER WEATHER ADVISORY MAY BE REQUIRED. GOOD MODEL CONSENSUS EXISTS BETWEEN THE 25.15Z SREF...25.18Z NAM/GFS AND 25.21Z RAP FOR SNOW TO MOVE INTO THE REGION VERY LATE TONIGHT INTO MONDAY MORNING. GOOD DYNAMICAL SUPPORT IN THE MORNING WITH A SHORTWAVE COMING THROUGH AS WELL AS HAVING THE LEFT EXIT REGION OF AN UPPER LEVEL JET SITUATED OVERHEAD. ADDITIONALLY...THE APPROACH OF A WARM FRONT WILL PROVIDE LOW LEVEL LIFT. THE CONCERN BECOMES WHEN THE SHORTWAVE AND LEFT EXIT REGION LEAVE THE AREA BY LATE MORNING...CAUSING MID-LEVEL DRYING AND THUS LOSS OF ICE IN THE CLOUDS. MEANWHILE...WE STILL HAVE THAT WARM FRONT COMING INTO THE REGION FROM NEAR I-35 TO PROVIDE THAT LOW LEVEL LIFT. THUS IT APPEARS LIKELY WE SHOULD SEE SOME FREEZING DRIZZLE BY MID-LATE MORNING...ESPECIALLY ALONG THE MISSISSIPPI RIVER COUNTIES. ONE BENEFIT IS THAT SNOW IS STARTING OUT FIRST...WHICH SHOULD MINIMIZE THE IMPACT OF THE FREEZING DRIZZLE ON TRAVEL. HOWEVER...IF ROADS DO NOT GET TREATED...THEY COULD EASILY BE SLIPPERY DUE TO THE COMBINATION OF SNOW AND FREEZING DRIZZLE. ADDITIONALLY...THERE COULD BE ISSUES WITH THE SNOW COMING IN AT COMMUTE TIME. SO BOTH SOME PROS AND CONS FOR A WINTER WEATHER ADVISORY. ANOTHER CONCERN IS THAT THE WARM FRONT MAY NOT MAKE IT FARTHER EAST THAN A ROCHESTER TO OELWEIN LINE...KEEPING THE MISSISSIPPI RIVER COUNTIES AT OR BELOW FREEZING THROUGH THE AFTERNOON...WHICH WOULD BE COLDER THAN OUR CURRENT FORECAST. ALTHOUGH THE LOW LEVEL LIFT IS PROGGED TO WEAKEN IN THE AFTERNOON...THERE IS PLENTY TO KEEP SOME DRIZZLE GOING...WHICH COULD THEN FREEZE IF OUR TEMPERATURES STAY COLD. ON THE OTHER HAND...DAYLIGHT THROUGH THE CLOUDS MAY HEAT UP ROADS ENOUGH TO PREVENT ICING. NEEDLESS TO SAY...PLENTY OF UNCERTAINTIES. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 257 PM CST SUN JAN 25 2015 CHALLENGES CONCERN PRECIPITATION CHANCES/AMOUNTS/TYPE LATE TONIGHT THROUGH MONDAY WITH THE NEXT CANADIAN TROUGH MOVING THROUGH NORTHWEST FLOW ALOFT. 25.12Z MODEL SUITE IN GOOD OVERALL AGREEMENT WITH PRECIPITATION PLACEMENT...BUT DIFFER SLIGHTLY ON AMOUNTS... ESPECIALLY EAST OF THE MS RIVER VALLEY. WILL USE A BLENDED SOLUTION OF THE 25.12Z GFS/NAM/ECMWF/GEM WITH ADDITIONAL SUPPORT FROM THE LATEST SUITE OF HIGH-RESOLUTION MODEL GUIDANCE. THIS EVENING WILL BE PARTLY TO MOSTLY CLOUDY AND COOL WITH TEMPERATURES DROPPING INTO THE LOWER TEENS TO LOWER 20S. PRECIPITATION WILL HOLD OFF UNTIL AFTER MIDNIGHT WHEN AN 850 HPA TROUGH OVER CENTRAL MANITOBA/EASTERN DAKOTAS MOVES ACROSS MN AND INTO THE UPPER MS RIVER VALLEY. MODEST MID-LEVEL WARM AIR ADVECTION/ISENTROPIC LIFT AND QG CONVERGENCE ALONG FRONTAL BOUNDARY WILL SLIDE FROM WEST TO EAST ACROSS THE FORECAST AREA MONDAY MORNING. INITIAL THERMAL/MOISTURE PROFILES ARE COLD ENOUGH AND SATURATED TO AROUND 500 HPA FOR ALL SNOW. HOWEVER...AS DAY PROGRESSES...ICE LOSS OCCURS AS 700 TO 500 HPA LAYER DRYS OUT. WITH SUB-FREEZING BOUNDARY LAYER TEMPERATURES...EXPECT SNOW TO TRANSITION TO FREEZING DRIZZLE FROM WEST TO EAST THROUGH THE DAY. SNOW ACCUMULATION WILL BE GREATEST ALONG AND EAST OF A LINE FROM EAU CLAIRE TO BLACK RIVER FALLS TO PLATTEVILLE WITH 1 TO 2 INCHES. FARTHER WEST TO THE MS RIVER...A QUICKER CHANGE OVER TO DRIZZLE WILL KEEP SNOW AMOUNTS GENERALLY IN THE HALF INCH TO AN INCH RANGE. SNOW WEST OF THE RIVER WILL BE A TRACE TO HALF INCH. A THIN GLAZE OF ICE FROM FREEZING DRIZZLE IS POSSIBLE MONDAY MORNING...ESPECIALLY ALONG AND EAST OF THE MS RIVER VALLEY...BUT BECAUSE THERE IS LIKELY TO BE A SHARP CUT-OFF BETWEEN THE STRONGEST FORCING/BACK EDGE OF PRECIPITATION AND WHEN ICE LOSS OCCURS... CONFIDENCE NOT HIGH ENOUGH AT THIS TIME TO HOIST AN ADVISORY. IMPACTS TO THE MORNING COMMUTE A POSSIBILITY AND CERTAINLY SOMETHING TO KEEP A CLOSE EYE ON THIS EVENING AND OVERNIGHT. IF ICE ACCUMULATION DOES HAPPEN...IT SHOULD QUICKLY MELT AS TEMPERATURES RISE TO ABOVE FREEZING FOR ALL AREAS EXCEPT THE FAR EAST BEHIND THE WARM FRONT. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 257 PM CST SUN JAN 25 2015 LINGERING LIGHT SNOW/FREEZING DRIZZLE WILL PUSH EAST MONDAY NIGHT WITH DRY CONDITIONS THROUGH TUESDAY AS SURFACE HIGH PRESSURE BUILDS ACROSS THE REGION. SHOULD SEE SOME SUN BY LATE TUESDAY WITH TEMPERATURES RISING INTO THE LOWER TO MID 30S. WEDNESDAY WILL BE DRY AND POTENTIALLY QUITE WARM AS LOW PRESSURE DRIFTS ACROSS THE REGION AND KEEPS MOST OF THE FORECAST AREA WITHIN THE WARM SECTOR. PRECIPITATION WILL REMAIN TO THE NORTH WITH 850 HPA TEMPERATURES ACROSS THE UPPER MS RIVER VALLEY FROM +2 TO +5 C. CLOUD COVER COULD LIMIT TEMPERATURE RISE...BUT LOWER 40S A REAL POSSIBILITY...ESPECIALLY ACROSS NORTHEAST IA INTO SOUTHWEST WI. PRECIPITATION CHANCES INCREASE WEDNESDAY NIGHT INTO THURSDAY AS MID-LEVEL WAVE WRAPS-UP ACROSS WI. LATE THURSDAY THROUGH SUNDAY...NORTHWEST FLOW ALOFT PERSISTS ALLOWING A SERIES OF WEAK WAVES TO TRANSLATE ACROSS THE UPPER MIDWEST. THE STRONGEST OF THESE IMPACTS THE REGION FRIDAY NIGHT INTO SATURDAY WITH A 20-30 PERCENT CHANCE OF LIGHT SNOW. TEMPERATURES FOR THE LATTER HALF OF THE WEEK INTO NEXT WEEKEND WILL DROP SLIGHTLY EACH DAY AS AN ARCTIC TROUGH DROPS SOUTH ACROSS EASTERN CANADA AND INTO THE EASTERN CONUS. HIGHS IN THE UPPER 20S TO LOWER 30S ON THURSDAY WILL DROP INTO THE MID TEENS TO LOWER 20S BY SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1135 PM CST SUN JAN 25 2015 MVFR STRATUS REMAINS OVER RST AND WAS EXPANDING QUICKLY TOWARDS LSE LATE THIS EVENING DUE TO SOUTHWEST WINDS PICKING UP. LSE SHOULD GO MVFR BY 07Z. ATTENTION THEN TURNS TO A LOW PRESSURE SYSTEM DROPPING SOUTHEAST THROUGH MN. THIS SYSTEM WILL BRING SNOW INTO THE TAF SITES AROUND 11Z...ALONG WITH A DROP OF VISIBILITIES AND CEILINGS TO IFR. RST COULD EVEN GO LIFR IN CEILINGS. TOWARDS 13Z AT RST AND 16Z AT LSE...THE ICE IN THE CLOUDS IS EXPECTED TO BE LOST...CAUSING THE SNOW TO CHANGE TO FREEZING DRIZZLE. SWITCHING THE PRECIPITATION TYPE WILL HELP TO IMPROVE VISIBILITY TO MVFR. HOWEVER...LITTLE CHANGE IS EXPECTED TO CEILING. PRECIPITATION SHOULD END BY NOON AT RST AS A WARM FRONT MOVES IN...BUT WINDS WILL INCREASE FROM THE WEST AND EVENTUALLY NORTHWEST LATE IN THE DAY WITH A COLD FRONTAL PASSAGE. LSE IS TRICKY WIND WISE WITH BOTH FRONTS FORECAST TO LAY UP RIGHT NEAR THE TAF SITE FOR THE AFTERNOON AND EVENING. NEVERTHELESS...BOTH SITES EXPECTED TO SEE CEILINGS INCREASE TO MVFR LATE IN THE DAY INTO THE EVENING AS MIXING INCREASES. LOOKING AT TOTAL SNOWFALL AMOUNTS LESS THAN 1 INCH...WHILE A LIGHT GLAZING OF ICE COULD OCCUR...ESPECIALLY AT LSE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY FROM 5 AM TO NOON CST MONDAY FOR WIZ017- 029-032>034-041-042-053. MN...WINTER WEATHER ADVISORY FROM 5 AM TO NOON CST MONDAY FOR MNZ079- 088-096. IA...NONE. && $$ UPDATE...AJ SHORT TERM...ROGERS LONG TERM...ROGERS AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
346 AM CST WED JAN 28 2015 .SHORT TERM... 345 AM CST TODAY THROUGH FRIDAY NIGHT... MAIN FORECAST CONCERNS IN THE SHORT TERM ARE CLOUD AND TEMP TRENDS TODAY AND TONIGHT...AND TIMING...COVERAGE AND TYPE OF PRECIPITATION TONIGHT AND THURSDAY AS LOW PRESSURE ORGANIZING OVER THE PLAINS MOVES EAST. RELATIVELY QUIET WEATHER THIS MORNING AS SURFACE HIGH PRESSURE DRIFTS SLOWLY EAST OF THE AREA. SUBSIDENCE ASSOCIATED WITH HEIGHT RISES ALOFT HAS LED TO A STRONG INVERSION AT AROUND 900 HPA HOWEVER PER DVN 00Z SOUNDING...WHICH HAS TRAPPED LOW CLOUDS ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA OVERNIGHT. CLOUDS WERE SLOWLY ERODING FROM THE SOUTHEAST THANKS TO 950-900 HPA WINDS GRADUALLY VEERING TO THE SOUTHEAST AND SOUTH...AND LOWERING SUBSIDENCE INVERSION. RAP GUIDANCE INDICATES SOUTH WINDS WILL INCREASE THIS MORNING AND SHOULD CONTINUE TO LIFT THESE LOWER CLOUDS NORTH TOWARD THE WI BORDER...THOUGH OVERALL NORTH CENTRAL ILLINOIS IS LIKELY TO BE CLOUDIER THAN AREAS SOUTH AND EAST TODAY EVEN AS MID AND HIGH CLOUDS BEGIN TO INCREASE AS WARM ADVECTION DEVELOPS ALOFT. SURFACE LOW PRESSURE IS ALREADY TAKING SHAPE ACROSS THE PLAINS TO OUR WEST THIS MORNING...IN RESPONSE TO A SHORT WAVE TROUGH EMERGING FROM THE CENTRAL/NORTHERN ROCKIES. SURFACE PRESSURE FALLS AHEAD OF THIS DEVELOPING LOW WILL LEAD TO INCREASING SOUTH-SOUTHEAST WINDS NEAR 25 MPH THIS AFTERNOON. DESPITE SOUTHERLY FLOW...LOW LEVEL PARCEL TRAJECTORIES WILL BE LARGELY FROM INDIANA/OHIO WHERE STRONG COOLING HAS OCCURRED NEAR THE SURFACE HIGH THIS MORNING. COMBINED WITH SOME MID/HIGH CLOUD COVER THIS MAY MAKE FOR HIGH TEMPERATURES COMING LATER IN THE DAY WHEN LOW LEVEL WINDS VEER MORE SOUTHERLY AND TAP MILDER AIR CURRENTLY ACROSS THE MISSOURI VALLEY. STRONG SOUTH FLOW WILL CONTINUE TONIGHT AHEAD OF THE APPROACHING SURFACE LOW...ALLOWING TEMPS TO STAY ABOVE FREEZING IN MOST AREAS. GUIDANCE IN GOOD AGREEMENT IN DEVELOPING SOME LIGHT SPOTTY PRECIPITATION ACROSS THE AREA LATE THIS EVENING...EXPANDING OVERNIGHT ESPECIALLY ACROSS NORTHERN/NORTHEASTERN PARTS OF THE FORECAST AREA. FORECAST SOUNDINGS INDICATE WARM LAYER TEMPS ALOFT IN THE +5C RANGE OR BETTER...WITH SATURATION INITIALLY OCCURRING BELOW 700 HPA AND SUPPORTING LIGHT RAIN. WITH BREEZY SOUTH SURFACE WINDS KEEPING TEMPS ABOVE MAINLY ABOVE FREEZING...PRECIPITATION TYPE IS EXPECTED TO REMAIN LIQUID IN MOST LOCATIONS. LOW PROBABILITY DOES EXIST FOR LIGHT FREEZING RAIN ESPECIALLY ACROSS FAR NORTH/NORTHEAST IL...BUT AT THIS TIME FEEL IT IS FAIRLY UNLIKELY. THE SURFACE LOW...AND A PAIR OF UN-PHASED SHORT WAVES....MOVE ACROSS THE CWA DURING THE MORNING AND RESULT IN WINDS SHIFTING TO THE NORTHWEST. THIS BRINGS COLDER AIR INTO THE REGION WITH COLLAPSING THICKNESS FIELDS SUPPORTING LINGERING PRECIPITATION CHANGING OVER FROM LIGHT RAIN TO A BRIEF RAIN/SLEET/SNOW MIX BEFORE ENDING FROM WEST-EAST. MOST PRECIPITATION SHOULD END BY NOON WEST OF ABOUT THE IL/IN STATE LINE...AND SHORTLY AFTER ACROSS NORTHWEST INDIANA. HOWEVER...GUSTY NORTH-NORTHWEST WINDS AND COLDER AIR SPREADING ACROSS LAKE MICHIGAN WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS ACROSS PARTS OF EASTERN LAKE AND PORTER COUNTIES ESPECIALLY THURSDAY EVENING INTO EARLY FRIDAY MORNING. THE REMAINDER OF THE AREA WILL JUST BE BLUSTERY AND COLDER...WITH NORTH-NORTHWEST WINDS GUSTING ABOVE 30 MPH AT TIMES THURSDAY BEFORE SLOWLY DIMINISHING THURSDAY NIGHT. AFTER MORNING HIGHS IN THE MID-UPPER 30S OR EVEN NEAR 40 IN SOME SPOTS...THURSDAY NIGHT LOOKS TO BE COLD WITH LOWS IN THE TEENS TO LOW 20S AND SINGLE DIGIT WIND CHILLS. SURFACE HIGH PRESSURE SPREADS INTO THE AREA AGAIN ON FRIDAY...WITH TEMPERATURES STRUGGLING INTO THE MID-UPPER 20S BUT WITH MUCH LIGHTER WINDS. LAKE SNOW SHOWERS WILL DIMINISH ACROSS NORTHWEST INDIANA AS INVERSION HEIGHTS LOWER AND LOW LEVEL WINDS DIMINISH...WITH SUNSHINE ELSEWHERE. RATZER && .LONG TERM... 345 AM CST SATURDAY THROUGH TUESDAY... THE MAIN FOCUS IN THE EXTENDED PERIOD IS ON A STORM SYSTEM WHICH LOOKS TO LIFT THROUGH THE OHIO VALLEY LATE SATURDAY NIGHT THROUGH SUNDAY. ECMWF/GFS ARE IN RELATIVELY GOOD AGREEMENT IN TAKING SURFACE LOW TRACK ALONG THE OHIO RIVER...THOUGH GFS IS A LITTLE SLOWER AND GEFS ENSEMBLE MEMBERS STILL SHOW QUITE A BIT OF SPREAD IN THEIR SOLUTIONS AT THE SURFACE. GEM ALSO SLOWER AND A BIT FARTHER SOUTH THAN THE OTHER GLOBAL MODELS. DEPENDING UPON HOW THIS SYSTEM EVENTUALLY TRACKS...IT COULD BE A SNOW PRODUCER FOR ALL OR PART OF THE CWA...AS IT TAPS GULF MOISTURE DEFORMATION BAND WOULD LIKELY CROSS CENTRAL IL/IN. GLOBAL MODELS ALSO INDICATE A STRONG SURGE OF ARCTIC AIR IN THE WAKE OF THIS SYSTEM...WITH SIGNIFICANTLY COLDER WEATHER I.E. LOWS +/- SINGLE DIGITS AND HIGHS PERHAPS ONLY IN THE TEENS BY MONDAY/TUESDAY. RATZER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * LOW CHANCE FOR 1500-2500 FT CIGS BEFORE 14Z. * GUSTY SOUTH-SOUTHEAST SURFACE WINDS DEVELOPING BY 18Z. * CHANCE FOR SCATTERED LIGHT RAIN SHOWERS BEGINNING LATE THIS EVENING. * SOUTH-SOUTHWEST WINDS OF AT LEAST 50 KT AROUND 2000 FT THIS EVENING INTO OVERNIGHT THAT MAY CREATE LOW-LEVEL WIND SHEAR. //DISCUSSION...UPDATED 06Z... AS HIGH PRESSURE MOVES EAST OVERNIGHT...SOUTHERLY WINDS WILL START TO BRING CLOUDS ACROSS NORTHWEST AND WEST CENTRAL ILLINOIS BACK NORTH TO NORTHEASTWARD. WHILE THE CLOUDS ARE THIN...THEY ARE UNDER A STRONG INVERSION OF 8C/1000 FT...SO NOT ENVISIONING MUCH MORE EROSION OVERNIGHT. RFD SHOULD GO BACK TO BROKEN OR EVEN OVERCAST AS THESE CLOUDS EXPAND BACK NORTHWARD AND IT IS POSSIBLE ORD AND DPA DO AS WELL. WITH THE APPROACH OF LOW PRESSURE...SOUTH-SOUTHEAST WINDS WILL INCREASE WEDNESDAY WITH GUSTS LIKELY IN THE AFTERNOON AND PERSISTING INTO THE EVENING AS STRONG PRESSURE FALLS SPREAD OVER. GIVEN THE CURRENT AND FORECAST PLACEMENT OF THE LOW PRESSURE...THE WIND DIRECTION SHOULD BE EAST OF SOUTH MUCH OF WEDNESDAY AND EARLY WEDNESDAY EVENING...BEFORE GRADUALLY VEERING DURING LATER WEDNESDAY NIGHT. A COLD FRONT WILL PASS IN THE PRE-DAWN HOURS. AHEAD...ALONG...AND BEHIND THIS FRONT WILL BE POTENTIAL FOR SCATTERED RAIN SHOWERS...WITH THAT CHANGING TO A RAIN AND SNOW SHOWER CHANCE DURING THE DAY THURSDAY. //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH THAT IF MVFR CIGS DO RETURN PRIOR TO 14Z THEY WOULD BE TEMPORARY. * HIGH IN WIND SPEED AND IN WIND DIRECTION BEING SLIGHTLY EAST OF SOUTH THROUGH THE DAY. MEDIUM IN WIND DIRECTION TONIGHT. //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...CHANCE OF RAIN/SNOW. MVFR LIKELY/IFR POSSIBLE. FRIDAY...VFR. WX NIL. SATURDAY...CHANCE OF SNOW IN THE AFTERNOON AND OVERNIGHT. VFR EARLY THEN MVFR LIKELY/IFR POSSIBLE. SUNDAY...CHANCE OF SNOW. IFR POSSIBLE. MONDAY...VFR. WX NIL. MTF/KREIN && .MARINE... 158 AM CST AN ACTIVE PERIOD WILL UNFOLD OVER LAKE MICHIGAN THROUGH THIS FORECAST THANKS TO THE PROGRESSIVE NATURE IN THE WEATHER PATTERN. HIGH PRESSURE EARLY THIS MORNING WILL EXIT THE PICTURE AND A QUICKLY APPROACHING LOW PRESSURE FROM THE WEST WILL BRING INCREASING SOUTHERLY WINDS LATER TODAY INTO THIS EVENING. DURING THE EVENING THERE IS A PERIOD WHERE OCCASIONAL GALES SHOULD OCCUR ACROSS THE SOUTHERN HALF AS SOME INSTABILITY WILL BE PRESENT WITH GALE FORCE WINDS ONLY 1000-1500 FT OFF THE WATER SURFACE. THE LOW SHOULD BE ELONGATED RIGHT DOWN THE AXIS OF THE LAKE AROUND 6 AM THURSDAY BEFORE IT QUICKLY MOVES EAST. THIS WILL RESULT IN STOUT NORTHWEST WINDS AND COLD ADVECTION ACROSS THE LAKE WITH WHAT LOOKS LIKE DEFINITE GALES FOR AT LEAST THE OPEN WATER...INCLUDING 40 KTS WITH 45 KTS EVEN POSSIBLE ESPECIALLY IN THE NORTH. THIS LIKELY WILL BRING SOME FREEZING SPRAY THURSDAY NIGHT TO THE OPEN WATER. AT THIS TIME FORECAST INGREDIENTS ARE A LITTLE SHY FOR HEAVY FREEZING SPRAY SO NO WATCH FOR THAT ISSUED BUT WILL NEED TO BE MONITORED. HAVE OPTED TO GO WITH A GALE WATCH FOR BEHIND THE LOW PRESSURE AS THAT TIME PERIOD WILL BE THE HIGHEST WINDS WITH THE SYSTEM. WILL JUST MENTION OCCASIONAL GALES ON THE FRONT SIDE DURING THIS EVENING ACROSS MAINLY THE SOUTH HALF. SMALL CRAFT ADVISORY CONDITIONS WILL OBVIOUSLY EXIST A GOOD AMOUNT OF THIS TIME ON THE ILLINOIS AND INDIANA NEAR SHORES. WITH A SHORT 4-6 HOUR RESPITE CENTERED ON DAYBREAK THURSDAY AS THE LOW PASSES...HAVE OPTED TO NOT EXTEND THE CURRENT SMALL CRAFT ADVISORY...BUT ONE WILL DEFINITELY BE NEEDED FOR THURSDAY AFTERNOON AND NIGHT...AND FOR THE INDIANA SHORE INTO FRIDAY. THE GALE WATCH DOES INCLUDE PARTS OF THE INDIANA NEARSHORE THAT WILL FEEL THE GREATER FETCH OF ONSHORE WINDS AND THUS COULD REALIZE GALES THURSDAY AFTERNOON AND EVENING. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...NOON WEDNESDAY TO 4 AM THURSDAY. GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON THURSDAY TO 3 AM FRIDAY. && $$ 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
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1149 PM CST TUE JAN 27 2015 .UPDATE... 905 PM CST LOW CLOUD COVER CONTINUES TO SLOWLY MOVE WESTWARD AND HAS CLEARED ALL BUT THE WESTERN FRINGES OF THE FORECAST AREA THIS EVENING. SATELLITE SHOWS SOME HIGHER CLOUD STREAKS APPROACHING FROM THE NORTHWEST AS UPPER RIDGING SHIFTS EASTWARD BUT COVERAGE LOOKS LOOKS TO BE SPORADIC THROUGH THE NIGHT AND MAY BE AT A MINIMUM DURING THE EARLY OVERNIGHT. TEMPERATURES HAVE BEGUN TO DROP OFF WHERE THANKS TO THE MAINLY CLEAR SKIES WITH SEVERAL SITES IN NORTH-CENTRAL ILLINOIS NOW IN THE TEENS. GIVEN THAT HIGHER CLOUD COVER LOOKS INTERMITTENT AND WINDS WILL DROP OFF WITH HIGH PRESSURE MOVING OVERHEAD HAVE GONE AHEAD AND LOWERED MINS OVERNIGHT FOR MOST AREAS...THOUGH WESTERN FRINGES MAY SEE LOWER LEVEL CLOUD COVER LINGER THROUGH THE NIGHT. WILL GO WITH LOWER TEENS FOR MUCH OF THE WESTERN/CENTRAL CWA AND SOME OF THE TRADITIONALLY COLDER SPOTS FROM LEE/OGLE COUNTIES TO DEKALB AND KANE COUNTIES COULD SEE VALUES A LITTLE BIT LOWER IF HIGH CLOUD COVER REMAINS VERY MINIMAL. WITH THE LOWER TEMPS AND SPORADIC HIGHER CLOUD COVER...FREEZING FOG WILL BE A CONCERN. THE COLDEST AREAS WILL LIKELY SEE A QUICK DROP OFF IN THE NEXT FEW HOURS WHICH MAY LEAD TO MORE FROST DEPOSITION RATHER THAN FOG FORMATION. WITH LIMITED CONFIDENCE IN THIS HAPPENING AND REASONABLE SUPPORT FOR SOME FOG DEVELOPMENT...WILL GO AHEAD AND ADD PATCHY FOG TO MUCH OF THE CENTRAL AND WESTERN CWA OR FROM THE FAR WESTERN CHICAGO METRO WEST AND SOUTHWEST FOR NOW. THIS MAY CAUSE SOME SLICK SPOTS ON ROADS OVERNIGHT. MDB && .SHORT TERM... 304 PM CST THROUGH THURSDAY... PRIMARY CONCERN IN THE NEAR TERM REVOLVES AROUND THE STRATUS DECK CURRENTLY OVER THE SOUTHWESTERN 2/3RDS OF THE CWA. WOULD ANTICIPATE A CONTINUED VERY SLOW CLEARING FROM THE EAST FOR A COUPLE MORE HOURS BEFORE LOW LEVEL FLOW DIMINISHES THIS EVENING BEFORE BACKING TO SOUTHERLY OVERNIGHT...WHICH MAY WELL SEND STRATUS SLOSHING BACK NORTH INTO AREAS THAT HAD PREVIOUSLY CLEARED OUT. TRIED TO REFLECT A TREND LIKE THIS IN THE HOURLY SKY GRIDS AND RESULTANT TEMPERATURE GRIDS...BUT GIVEN THE POOR MODEL HANDLING OF THIS CLOUDINESS IT PRETTY MUCH GUARANTEED THAT OUR CURRENT SKY GRIDS WILL BE WRONG SOMEWHERE AND NEED UPDATING WITH ACCOMPANYING CHANGES NEEDED IN TEMPS TONIGHT. WHERE SKIES BECOME/STAY CLEAR TONIGHT COULD SEE FREEZING GROUND FOG DEVELOP GIVEN THE LIGHT WINDS...BUT WILL LET EVENING SHIFT WATCH TRENDS AND ADD FREEZING FOG AS NEEDED. FOR WEDNESDAY HAVE OPTED TO BE OPTIMISTIC IN PUSHING STRATUS NORTH AND BREAKING IT UP IN THE MORNING BUT THIS VERY WELL MAY END UP BEING TOO OPTIMISTIC. ASSUMING THERE IS SOME SUNSHINE TOMORROW PRIOR TO THE ARRIVAL OF EXTENSIVE MID AND HIGH LEVEL CLOUDINESS THEN HIGHS COULD PUSH WELL INTO THE 30S...PARTICULARLY IN THE LESS SNOW COVERED AND MORE URBANIZED AREAS. DEVELOPING LOW PRESSURE TO OUR WEST SHOULD RESULT IN TIGHTENING PRESSURE GRADIENT AND STRENGTHENING SOUTHERLY WINDS WEDNESDAY. IZZI && .LONG TERM... 304 PM CST THURSDAY NIGHT THROUGH TUESDAY... BRISK SOUTH WINDS...WARM AIR ADVECTION...AND CLOUD COVER IN ADVANCE OF THE SYSTEM WEDNESDAY NIGHT SHOULD RESULT IN NEARLY STEADY TEMPS IN THE EVENING AND PROBABLY RISING A BIT OVERNIGHT. COULD SEE A BIT OF LIGHT RAIN OR DRIZZLE IN THE WARM SECTOR WEDNESDAY NIGHT FOLLOWED BY SOME POTENTIAL FOR A BIT OF WRAP AROUND RAIN OR SNOW SHOWERS THURSDAY ON THE BACK SIDE OF THE SYSTEM. STILL LOOKS LIKE PRETTY LIMITED MOISTURE WITH THE SYSTEM AND HIGHEST QPF FOCUSED TO OUR NORTH WITH LIGHT AMOUNTS IN OUR CWA AND ONLY MINIMAL THREAT OF ANY ACCUMULATED FROZEN/FREEZING PRECIP GIVEN THE FORECAST TRACK AND TEMPS. SHOT OF SEASONABLY COLD AIR WILL KNOCK TEMPS TO JUST A HAIR BELOW AVERAGE FRIDAY. VIGOROUS ALBERTA CLIPPER IS FORECAST TO RESULT IN AN AMPLIFYING LONG WAVE TROUGH OVER THE CENTRAL CONUS THIS WEEKEND. STILL SOME LARGE SPREAD BETWEEN MODELS WITH RESPECT TO THE DETAILS THIS WEEKEND...BUT THERE HAS BEEN SOME AGREEMENT THE PAST COUPLE DAYS ON THE GENERAL IDEA OF A LARGE SWATH OF ACCUMULATING SNOW POTENTIALLY AFFECTING THE REGION SAT NIGHT INTO SUNDAY. ARCTIC AIR IS FORECAST TO SURGE SOUTH INTO THE AREA IN THE WAKE OF THIS SYSTEM EARLY NEXT WEEK...BUT THE DURATION AND MAGNITUDE OF THIS ARCTIC INTRUSION ARE DEPENDENT ON WHICH MODEL YOU LOOK AT MEANING FAIRLY LOW FORECAST CONFIDENCE AT THIS POINT. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * CHANCE FOR 1500-2500 FT CIGS BEFORE 14Z. * GUSTY SOUTH-SOUTHEAST SURFACE WINDS DEVELOPING BY 18Z. * CHANCE FOR SCATTERED LIGHT RAIN SHOWERS BEGINNING LATE WEDNESDAY EVENING. * SOUTH-SOUTHWEST WINDS OF AT LEAST 50 KT AROUND 2000 FT WEDNESDAY EVENING THAT MAY CREATE LOW-LEVEL WIND SHEAR. //DISCUSSION...UPDATED 06Z... AS HIGH PRESSURE MOVES EAST OVERNIGHT...SOUTHERLY WINDS WILL START TO BRING CLOUDS ACROSS NORTHWEST AND WEST CENTRAL ILLINOIS BACK NORTH TO NORTHEASTWARD. WHILE THE CLOUDS ARE THIN...THEY ARE UNDER A STRONG INVERSION OF 8C/1000 FT...SO NOT ENVISIONING MUCH MORE EROSION OVERNIGHT. RFD SHOULD GO BACK TO BROKEN OR EVEN OVERCAST AS THESE CLOUDS EXPAND BACK NORTHWARD AND IT IS POSSIBLE ORD AND DPA DO AS WELL. WITH THE APPROACH OF LOW PRESSURE...SOUTH-SOUTHEAST WINDS WILL INCREASE WEDNESDAY WITH GUSTS LIKELY IN THE AFTERNOON AND PERSISTING INTO THE EVENING AS STRONG PRESSURE FALLS SPREAD OVER. GIVEN THE CURRENT AND FORECAST PLACEMENT OF THE LOW PRESSURE...THE WIND DIRECTION SHOULD BE EAST OF SOUTH MUCH OF WEDNESDAY AND EARLY WEDNESDAY EVENING...BEFORE GRADUALLY VEERING DURING LATER WEDNESDAY NIGHT. A COLD FRONT WILL PASS IN THE PRE-DAWN HOURS. AHEAD...ALONG...AND BEHIND THIS FRONT WILL BE POTENTIAL FOR SCATTERED RAIN SHOWERS...WITH THAT CHANGING TO A RAIN AND SNOW SHOWER CHANCE DURING THE DAY THURSDAY. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM THAT IF MVFR CIGS DO RETURN PRIOR TO 14Z THEY WOULD BE TEMPORARY. * HIGH IN WIND SPEED AND IN WIND DIRECTION BEING SLIGHTLY EAST OF SOUTH THROUGH THE DAY WEDNESDAY. MEDIUM IN WIND DIRECTION WEDNESDAY EVENING. //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...CHANCE OF RAIN/SNOW. MVFR LIKELY/IFR POSSIBLE. FRIDAY...VFR. WX NIL. SATURDAY...CHANCE OF SNOW IN THE AFTERNOON AND OVERNIGHT. VFR EARLY THEN MVFR LIKELY/IFR POSSIBLE. SUNDAY...CHANCE OF SNOW. IFR POSSIBLE. MONDAY...VFR. WX NIL. MTF/KREIN && .MARINE... 318 PM CST LIGHTER NORTHERLY WINDS IN PLACE THIS AFTERNOON AS HIGH PRESSURE SPANS THE REGION...WILL FURTHER DIMINISH THIS EVENING AS THIS HIGH MOVES OVERHEAD. THIS HIGH WILL THEN CONTINUE SOUTHEAST TOWARDS THE OHIO VALLEY TONIGHT AS A TROUGH OF LOW PRESSURE MOVES EAST ACROSS THE CENTRAL PLAINS. THIS WILL HELP THE WINDS TO TURN BACK MORE SOUTHERLY AND THEN BEGIN TO SLOWLY INCREASE LATER TONIGHT INTO WEDNESDAY. THIS INCREASING TREND WILL CONTINUE THROUGHOUT THE DAY WEDNESDAY...WITH SOUTHERLY WINDS REALLY INCREASING DURING THE AFTERNOON TIME FRAME. THIS WILL LIKELY CREATE WINDS HAZARDOUS FOR SMALL CRAFT...AND SO HAVE ISSUED A SMALL CRAFT ADVISORY FOR WEDNESDAY AFTERNOON THROUGH LATE WEDNESDAY NIGHT WHEN WINDS WILL DIMINISH WITH THE APPROACHING LOW PRESSURE. THIS WILL LIKELY BE BRIEF AS WINDS WILL QUICKLY INCREASE ONCE AGAIN ON THE BACKSIDE OF THIS SYSTEM THURSDAY. ALSO...SOUTHERLY WINDS ACROSS THE SOUTHERN HALF OF THE LAKE COULD HOVER AROUND 30 KT A FOR A BRIEF WINDOW WEDNESDAY NIGHT. WILL NEED TO MONITOR TRENDS DURING THIS PERIOD...BUT WILL MAKE MENTION OF OCCASIONAL GALE FORCE GUSTS DURING THIS TIME. EXPECT STRONG WINDS TO BE IN PLACE ON THURSDAY...REALLY INCREASING INTO THE AFTERNOON AND EVENING HOURS. GALES ARE APPEARING LIKELY FOR THE ENTIRE LAKE DURING THIS TIME...EVEN FOR THE NEARSHORE WATERS...BUT WITH SPEEDS DIMINISHING ONCE AGAIN LATE THURSDAY NIGHT INTO FRIDAY. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...NOON WEDNESDAY TO 4 AM THURSDAY. && $$ 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
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1139 PM CST Tue Jan 27 2015 .UPDATE... ISSUED AT 639 PM CST TUE JAN 27 2015 Made some quick updates to the forecast this evening, mainly to better reflect current and expected sky trends. 00z/6pm IR satellite imagery shows cloud cover steadily eroding from the E/NE, with mostly clear skies currently noted along/northeast of a Champaign to Paris line. Clouds are beginning to break up south of there along/south of the I-70 corridor as well. Based on satellite loops and the latest HRRR forecast, it appears skies will become partly to mostly clear across much of the KILX CWA tonight, except perhaps the far NW around Galesburg. Will continue to monitor trends to see if additional updates are needed, but for now will hold on to overcast conditions through the entire night northwest of the Peoria area with clearing skies elsewhere. Low temperatures will be coldest where clearing has already occurred across the NE CWA around Danville, where readings will dip into the teens. Lower to middle 20s seem reasonable across the rest of central Illinois. && .SHORT TERM...(Through Wednesday afternoon) ISSUED AT 255 PM CST TUE JAN 27 2015 MAIN CHALLENGE IN THE SHORT/NEAR TERM REVOLVES AROUND CLOUD COVER TONIGHT...WINDS AND TEMPS ON WEDNESDAY. A SURFACE RIDGE IS IN PLACE OVERHEAD...AND SATELLITE PICTURES SHOW LOWER CLOUDS ERODING FROM THE NORTHEAST THIS AFTERNOON AS DRIER AIR FILTERS IN. BEST CHANCES FOR EROSION WILL BE FOR EASTERN AREAS WHERE THIS DRIER AIR IS MAKING BETTER HEADWAY. RAW MODEL GUIDANCE CONTINUES TO ADVERTISE CLEARING MUCH SOONER THIS EVENING AREA-WIDE...WHILE RAP TIME HEIGHTS SUGGEST IT WILL TAKE UNTIL LATER TONIGHT FOR THIS TO OCCUR...ESPECIALLY NORTH OF I-72. MODEL SOUNDINGS SUGGEST THAT THIS LOWER LEVEL MOISTURE WILL REMAIN TRAPPED BELOW A SUBSIDENCE INVERSION...AND THAT IT WILL AT LEAST HOLD FIRM THROUGH THE EVENING HOURS. CLOUD BEARING WINDS WILL BE TURNING MORE NORTHERLY AS WELL...WHICH WOULD SUPPORT CLOUDS HANGING ON ALONG AND WEST OF HIGHWAY 51. SURFACE HIGH PRESSURE TONIGHT WILL SHIFT OFF THE EAST TONIGHT AS THE UPPER RIDGE IN THE PLAINS MOVE EAST AND CONTINUES TO DEAMPLIFY. EXPECT WINDS TO SHIFT TO THE SE OVERNIGHT...WITH LOWS IN THE EAST IN THE UPPER TEENS TO NEAR 20...WITH 20S HOLDING WEST WHERE CLOUD COVER IS EXPECTED TO BE MORE PREVALENT. THURSDAY...ATTENTION SHIFTS TO UPPER LEVEL LOW PRESSURE MOVING THROUGH THE GREAT BASIN THIS AFTERNOON. THE UPPER TROUGH MOVES INTO THE PLAINS RIDGE WHILE ADDITIONAL PACIFIC ENERGY MOVES INTO THE NORTHERN PLAINS. LOW LEVEL WARM ADVECTION ENSUES IN THE SOUTHWESTERLY FLOW AHEAD OF THESE SYSTEM .IT APPEARS THAT NOT ALL OF OF THIS LOW LEVEL WARMING WILL NOT TRANSLATE TO THE SURFACE WITH A FAIRLY STRONG INVERSION HOLDING...BUT DO EXPECT SOME WARMING FROM TODAY`S READINGS...ESPECIALLY FOR SOUTHERN AND WESTERN AREAS WHERE MID 40S LOOK LIKE A DECENT BET. AREAS NORTH AND EAST WILL REMAIN ON THE COOLER SIDE STRUGGLING TO REACH 40. AHEAD OF THESE TWO DISTURBANCES SURFACE LOW PRESSURE OF 1005 MB COMBINES WITH THE DEPARTING HIGH TO CREATE A MODEST PRESSURE GRADIENT ACROSS THE AREA. A VERY STRONG LOW LEVEL JET SETS UP LATE IN THE AFTERNOON...BUT GIVEN THE LOW LEVEL INVERSION...EXPECT A BREEZY DAY WITH GUSTS IN THE 25 KT RANGE. KMD && .LONG TERM...(Wednesday Night through Tuesday) ISSUED AT 340 PM CST TUE JAN 27 2015 WEDNESDAY NIGHT THROUGH SATURDAY... A WINDY AND MILD NIGHT IS IN STORE ON WEDNESDAY NIGHT AS LOW PRESSURE QUICKLY MOVES JUST NORTH OF THE CWA. STRONG PRESSURE FALLS DUE TO TIGHTENING GRADIENT BETWEEN ADVANCING LOW AND DEPARTING HIGH PRESSURE TO THE EAST WILL RESULT IN SUSTAINED SOUTHERLY WINDS IN THE MID TO HIGH TEENS WITH GUSTS OF 20-25 KT. TEMPERATURES SHOULD DROP SOME IN THE EVENING BUT THEN ARE LIKELY TO SLOWLY RISE TOWARD DAYBREAK. THERE IS A DECENT VORT MAX ASSOCIATED WITH APPROACHING SHORT WAVE TROUGH...BUT GUIDANCE IS FAIRLY DRY WITH EXCEPTION OF ECMWF AND NAM. MAINTAINED SLIGHT TO LOW END CHANCE POPS FOR LIGHT RAIN MAINLY AFTER MIDNIGHT. MAY NEED TO ADD DRIZZLE TO GRIDS. COLD FRONT TRAILING FROM THE LOW PRESSURE WILL SWEEP ACROSS THE AREA FROM NW TO SE OVERNIGHT INTO THURSDAY MORNING...SHIFTING WINDS FROM SOUTHWEST TO NORTHWEST...AND COLD ADVECTION RAMPING UP BEHIND IT. HAVE LOW POPS FOR MOST OF THE CWA IN THE MORNING...BUT ANY PRECIP WOULD LIKELY BE LIGHT RAIN DESPITE COLD ADVECTION AS SURFACE TEMPERATURES WOULDNT COOL QUICK ENOUGH FROM EARLY HIGHS IN THE UPPER 30S TO MID 40S...WARMEST FAR SOUTHEAST. BIGGER STORY WILL BE STRONG ISALLOBARIC PRESSURE RISES BEHIND FRONT RESULTING IN NORTHWEST WINDS GUSTING TO 30-35 MPH MUCH OF THE MORNING AND AFTERNOON. WINDS WILL GRADUALLY DIMINISH THURSDAY NIGHT AS EXPANSIVE HIGH PRESSURE SPREADS SOUTHEAST. EXPECT LOWS IN THE UPPER TEENS TO MID 20S BY EARLY FRIDAY...RECOVERING TO SLIGHTLY BELOW CLIMO LOW-MID 30S UNDER LARGE CANADIAN HIGH. THE HIGH WILL SLIDE SOUTHEAST ON SATURDAY...ALLOWING TEMPS TO WARM SLIGHTLY TO THE MID TO UPPER 30S. SATURDAY NIGHT THROUGH TUESDAY... ATTENTION TURNS TO EJECTION OF CLOSED UPPER LOW OVER THE DESERT SOUTHWEST AS MORE OF AN OPEN WAVE SATURDAY NIGHT INTO SUNDAY...WITH ASSOCIATED WEAK SURFACE LOW POSSIBLY MOVING TOWARD THE LOWER OR MID MS VALLEY THEN OH VALLEY BY SUNDAY EVENING. WITH IT BEING STILL OVER 100 HRS OUT...GUIDANCE VARIES ON PLACEMENT OF SURFACE LOW...BUT DECENT AGREEMENT IN OPERATIONAL MODELS AND ENSEMBLES OF BROAD WARM ADVECTION/ISENTROPIC ASCENT WITH THIS SYSTEM. THIS YIELDS THE POTENTIAL FOR FAIRLY LONG DURATION PRECIPITATION. AT THIS POINT...THERMAL PROFILES APPEAR COLD ENOUGH FOR SNOW ACROSS THE CWA...BUT FARTHER NORTHWEST/STRONGER LOW COULD INTRODUCE P-TYPE CONCERNS...ESPECIALLY IN THE FAR SOUTHEAST. WAY TOO EARLY TO DISCUSS POTENTIAL SNOW ACCUMULATIONS...BUT THIS PERIOD BEARS WATCHING. BEHIND THIS SYSTEM...MODELS HAVE BEEN WAFFLING ON INTENSITY OF A POTENTIAL SHOT OF ARCTIC AIR EARLY NEXT WEEK AS PIECE OF POLAR VORTEX ROTATES SOUTH OF HUDSON BAY. BRUNT OF THE ARCTIC BLAST MAY BE DIRECTED FARTHER EAST...BUT STILL LOOKS LIKE THERE COULD BE A PERIOD OF WELL BELOW NORMAL TEMPERATURES EARLY NEXT WEEK. RC && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) ISSUED AT 1139 PM CST TUE JAN 27 2015 Skies have cleared across much of central and southeast Illinois late this evening, with MVFR ceilings persisting along/northwest of a KBMI to KIJX line. IR satellite imagery continues to show this area of clouds retreating to the northwest as light E/SE return flow develops on the back side of departing high pressure. Based on satellite loops and latest HRRR forecast, have removed the ceiling at KBMI by 07z, then further northwest to KPIA by 09z. Will need to keep an eye out for potential fog development, as HRRR has been trying to develop areas of fog across the E/NE CWA all evening. Latest obs show little or no obstruction to visby and with dewpoints in the upper teens/lower 20s, do not think widespread/dense fog will develop. Will however forecast slight reductions in visby down to around 3-4 miles overnight. As the high moves further away, strong southeasterly winds will develop on Wednesday. Forecast soundings suggest gusts in the 20-25kt range from late morning through the evening hours as the pressure gradient continues to tighten. Next fast-moving storm system will approach from the west late in the day, bringing an increase in mid-level cloudiness but no precip through 06z Thu. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barnes SHORT TERM...kmd LONG TERM...RC AVIATION...Barnes
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1129 PM CST TUE JAN 27 2015 .DISCUSSION... 28/06Z TAF ISSUANCE. && .AVIATION... NO MAJOR CHANGES FROM PREVIOUS THINKING...ALTHOUGH A QUICK LOOK OUTSIDE SHOWS SOME SHALLOW GROUND FOG BEGINNING TO DEVELOP HERE AT THE LCH AIRPORT. LATEST HRRR SHOWS THE POTENTIAL FOR LOWER VSBYS AT BPT AND POSSIBLY LCH...BUT GIVEN DRY AIRMASS IN PLACE ACRS THE REGION...FOG SHOULD REMAIN PATCHY AND SHALLOW. INCLUDED TEMPO GROUPS AT BPT/LCH FOR OCCASIONAL MVFR VSBYS BETWEEN 08-12Z...BUT OTHERWISE VFR SHOULD PREVAIL. 24 && .PREV DISCUSSION... /ISSUED 844 PM CST TUE JAN 27 2015/ UPDATE... THE LATEST UPPER AIR SOUNDING (28/00Z) FROM KLCH VERIFIES WHAT IS SEEN ON WATER VAPOR IMAGERY...AS A DRY AIR MASS PREVAILS. SOME LIGHT SOUTHERLY WINDS HAVE RISEN THE DEW POINTS SOME THIS EVENING AT A FEW SPOTS. HOWEVER...WITH WINDS EXPECTED TO BE NEARLY CALM...AND CLEAR SKIES WITH A DRY AIR MASS...OVERNIGHT LOW TEMPERATURES STILL ON TRACK. WITH THIS...A FEW SITES MAY SEE SOME SHALLOW GROUND FOG AS AIR TEMPERATURES LATER ON REACH DEW POINTS. HOWEVER...THINKING IS THAT OVERALL AIR MASS IS TOO DRY TO SUPPORT ANY SIGNIFICANT FOG DEVELOPMENT AND WILL NOT PLACE IN WEATHER GRIDS AT THIS TIME. THEREFORE...NO CHANGES TO THE FORECAST FOR THE EVENING UPDATE. RUA PREV DISCUSSION... /ISSUED 519 PM CST TUE JAN 27 2015/ DISCUSSION... 28/00Z TAF ISSUANCE. AVIATION... HIGH PRES RIDGING SW ACRS THE AREA WILL MOVE SLOWLY EAST THROUGH WEDNESDAY. THE RESULT WILL BE VFR CONDITIONS WITH MAINLY SKC SKIES AND LT VRBL WINDS WHICH WILL VEER MORE SELY DURING THE DAY TOMORROW. 24 PREV DISCUSSION... /ISSUED 342 PM CST TUE JAN 27 2015/ DISCUSSION... LATEST WATER VAPOR IMAGERY SHOWS SUBSIDENCE AND A RATHER DRY AIR MASS ACROSS THE REGION. MEANWHILE...A WEAK SURFACE RIDGE ALSO LIES ACROSS THE REGION. THE COMBINATION OF THE TWO IS HELPING TO PROVIDE SUNNY SKIES...LIGHT WINDS...WHICH IN TURN IS ALLOWING FOR RATHER WARM AIR TEMPERATURES FOR LATE JANUARY...FOR LOCATIONS AWAY FROM THE GULF OF MEXICO...WITH READINGS IN THE MID TO UPPER 70S...SOME 15F DEGREES ABOVE NORMAL. SURFACE RIDGE WILL SLIDE OFF TO THE EAST ON WEDNESDAY...WITH SOUTHERLY WINDS OFF THE GULF GRADUALLY RETURNING TO THE FORECAST AREA. THIS WILL HELP MODIFY THE AIR MASS AT THE SURFACE WITH THE MORE MOIST AND COOLER GULF AIR HELPING TO KEEP TEMPERATURES ON WEDNESDAY LOWER THAN WHAT IS OCCURRING TODAY. HOWEVER...THESE VALUES WILL STILL BE SOME 10F DEGREES ABOVE NORMAL. THE INCREASE IN GULF LOW LEVEL MOISTURE WILL ALSO BRING ABOUT THE CHANCE FOR AT-LEAST PATCHY FOG DEVELOPMENT ON WEDNESDAY NIGHT INTO THURSDAY MORNING. A SHORT WAVE IS EXPECTED TO COME DOWN THE SIDE OF THE WESTERN U.S. RIDGE LATE TOMORROW AND MOVE EASTWARD ACROSS THE PLAINS AND GREAT LAKES THROUGH THURSDAY. THIS SYSTEM WILL HELP PUSH A WEAK COLD FRONT ACROSS THE FORECAST AREA ON THURSDAY EVENING. MOISTURE PROFILES DO HAVE PRECIPITABLE WATER VALUES NEARING 1 INCH WITH MEAN RH BRIEFLY OVER 50 PERCENT AHEAD OF THE FRONT. HOWEVER...TIME HEIGHTS SHOW THIS MOISTURE TO BE RATHER SHALLOW AND MAINLY BELOW 5K FEET. WITH UPPER LEVEL DYNAMICS ALSO STAYING WELL TO THE NORTH WITH THIS FRONT...DO NOT EXPECT ANY SIGNIFICANT SHOWER ACTIVITY TO DEVELOP WITH IT...AND WILL KEEP FRONTAL PASSAGE AS DRY. COOLER CONDITIONS ARE EXPECTED BEHIND THE FRONT FOR FRIDAY WITH HIGH TEMPERATURES BACK CLOSER TO SEASONAL NORMS. CUT OFF UPPER LEVEL LOW IS STILL EXPECTED TO FORM OVER THE SOUTHWEST U.S. BY THE END OF THE WEEK AND MOVE DOWN TOWARD THE BAJA CALIFORNIA/NORTHWEST OLD MEXICO AREA OVER THE WEEKEND. STRENGTHENING SOUTHERN JET WILL INCREASE PACIFIC MOISTURE ACROSS THE FORECAST AREA...AS WELL AS PUSH DISTURBANCES EJECTING OUT OF THE UPPER LEVEL LOW TOWARD THE FORECAST AREA. THIS WILL BRING ABOUT A CHANCE OF SHOWERS BY SATURDAY. SURFACE HIGH PRESSURE THAT BUILDS IN BEHIND THE COLD FRONT ON THURSDAY NIGHT WILL PUSH OFF TO THE EAST BY SATURDAY NIGHT...AND THIS WILL ALLOW SOUTHERLY WINDS TO DEVELOP DURING THIS TIME. THIS WILL ALSO HELP INCREASE MOISTURE PROFILES AS LOW LEVEL GULF MOISTURE WILL BE ADDED TO THE EAST PAC MOISTURE. PRECIPITABLE WATER VALUES INCREASE FOR SATURDAY NIGHT INTO SUNDAY TO BETWEEN 1.3 AND 1.5 INCHES...WITH MEAN RH OVER 90 PERCENT...BOTH RESPECTABLE NUMBERS FOR THE COOL SEASON. INCREASING LIFT FROM DISTURBANCES IN THE SOUTHERN JET...AS WELL AS AN APPROACHING COLD FRONT...THAT WILL MOVE ACROSS LATE SUNDAY...WILL TAP INTO THE DECENT MOISTURE TO PROVIDE A LIKELIHOOD OF SHOWERS FOR THE SATURDAY NIGHT INTO SUNDAY PERIOD. AT THIS POINT...SURFACE INSTABILITY REMAINS RATHER MEAGER...SO WILL KEEP ACTIVITY AS JUST SHOWERS...AND NOT MENTION THUNDER. SHOWERS WILL GRADUALLY END FROM THE NORTHWEST TO THE SOUTHEAST ON SUNDAY NIGHT AS DRIER AIR MOVES IN BEHIND THE FRONT. RUA MARINE... LIGHT SOUTHERLY WINDS ARE EXPECTED ON WEDNESDAY AS A SURFACE HIGH PRESSURE SYSTEM MOVES OFF TO THE EAST. THESE SOUTHERLY WINDS WILL BRING BACK A MORE MOIST MARINE AIR MASS INTO THE REGION...AND WITH DEW POINTS NEARING THE NEAR SHORE WATER TEMPERATURES...AT-LEAST SOME PATCHY SEA FOG IS EXPECTED TO DEVELOP ON WEDNESDAY NIGHT INTO THURSDAY. A COLD FRONT WILL MOVE ACROSS THE COASTAL WATERS ON THURSDAY EVENING...ENDING FOG CHANCES AND BRINGING MODERATE NORTHERLY WINDS. WIND SPEEDS WILL REMAIN MODERATE AND BECOME EASTERLY ON SATURDAY THEN SOUTHEASTERLY SATURDAY NIGHT INTO SUNDAY AS AN UPPER LEVEL DISTURBANCE HELPS FORM AN AREA OF LOW PRESSURE OVER TEXAS...THAT WILL MOVE ACROSS NORTHERN LOUISIANA. THIS SYSTEM WILL ALSO BRING WIDESPREAD SHOWER ACTIVITY UNTIL ANOTHER COLD FRONT MOVES ACROSS LATE SUNDAY. RUA && .PRELIMINARY POINT TEMPS/POPS... KLCH 45 69 51 73 / 0 0 0 0 KBPT 47 72 53 73 / 0 0 0 10 KAEX 41 71 49 73 / 0 0 0 0 KLFT 45 69 52 74 / 0 0 0 0 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...NONE. TX...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
413 AM EST WED JAN 28 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 426 PM EST TUE JAN 27 2015 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER THE CONUS...FEATURING A STRONG RIDGE OVER THE ROCKIES AND A DEEP TROF ALONG THE E COAST. RESULTING NW FLOW INTO THE GREAT LAKES IS QUIETER TODAY THAN YESTERDAY AS SUBTLE SHORTWAVE RIDGING IS JUST UPSTREAM OVER NRN ONTARIO. SO...THERE IS NO PCPN OF NOTE TODAY. THERE HAVE BEEN SOME -SHSN/FLURRIES OFF NRN LAKE MICHIGAN INTO MENOMINEE COUNTY...AND RECENTLY FLURRIES HAVE APPEARED ON KMQT RADAR IMAGERY IN CNTRL UPPER MI. AT THE SFC...HIGH PRES IS CENTERED OVER SRN QUEBEC WITH RIDGE EXTENDING BACK THRU THE UPPER LAKES. DRY AIR ASSOCIATED WITH THE HIGH HAS RESULTED IN A SUNNY DAY OVER ERN UPPER MI...ROUGHLY E OF A MUNISING-ESCANABA LINE. LOW CLOUDS HAVE BEEN PERSISTENT OVER THE REST OF THE AREA...THOUGH PORTIONS OF NW UPPER MI DID HAVE MOSTLY SUNNY SKIES EARLIER TODAY. QUIET WEATHER WILL CONTINUE TONIGHT WITH SHORTWAVE RIDGING PASSING ACROSS THE AREA. MAIN ISSUE WILL BE CLOUD TRENDS AND THE BIG IMPACT THE CLOUDS WILL HAVE ON TEMPS. WITH CLEAR SKIES AND LIGHT/CALM WIND TO START THE EVENING...THE ERN FCST AREA WILL BE COLDEST TONIGHT. LOWERED MINS TO AROUND 0F IN THAT AREA...BUT IT COULD BE 5 OR MORE DEGREES COLDER IF SKIES REMAIN CLEAR THRU THE WHOLE EVENING. OVERNIGHT...THERE WILL BE AN INCREASE IN CLOUDS DUE TO HIGH CLOUDS STREAKING SE WELL AHEAD OF THE NEXT SHORTWAVE MOVING ACROSS THE SRN CANADIAN ROCKIES AND POSSIBLY FROM LOW CLOUDS ADVECTING NE IN DEVELOPING SW FLOW. THIS WILL PUT THE BRAKES ON COOLING AND PROBABLY LEAD TO TEMPS RISING SOME OVERNIGHT. ACROSS THE REST OF THE FCST AREA...THE EXPANSE OF LOW CLOUDS EXTENDING W...SW AND S OVER MUCH OF MN AND WI SUGGESTS CLOUDS WILL DOMINATE FOR MUCH OF THE NIGHT UNDER LOW-LEVEL S TO SW WINDS. EVEN IF LOW CLOUDS CLEAR OUT IN SOME AREAS...HIGH AND MID CLOUDS WILL BE OVERSPREADING THE AREA. LOWS SHOULD GENERALLY BE IN THE 15-20F RANGE. ON WED....ONE SHORTWAVE WILL MOVE FROM THE SRN CANADIAN ROCKIES INTO THE DAKOTAS/MANITOBA WHILE A SECOND MOVES FROM WY/CO TO THE CNTRL PLAINS. AHEAD OF THE NRN WAVE...WAA/ISENTROPIC ASCENT WILL STRENGTHEN AND SHIFT ESE THRU THE DAY UNDERNEATH RIGHT ENTRANCE OF UPPER JET. WITH THE FOCUS OF MOIST ISENTROPIC ASCENT JUST TO THE N AND WITH DRIER AIR HOLDING ON AT LOW LEVELS...THE MAIN STREAK OF SNOW WILL REMAIN N OF HERE WED AFTN. MODEL AGREEMENT IS IN EXCELLENT AGREEMENT ON THIS POINT. HOWEVER...THERE IS SOME UNCERTAINTY IN WHETHER THE SRN EDGE OF THE SNOW MAY CLIP THE AREA. BASED ON STRENGTH OF ISENTROPIC ASCENT AND TEMP/MOISTURE PROFILES ON FCST SOUNDINGS...THE KEWEENAW AND FAR ERN FCST AREA MAY GET CLIPPED BY A LITTLE -SN. INCLUDED ONLY SCHC/LOW CHC POPS TO REFLECT THIS POTENTIAL. OTHERWISE...EXPECT A WARMER DAY WITH HIGHS IN THE UPPER 20S/LWR 30S. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 413 AM EST WED JAN 28 2015 FCST FOCUS IN THE MEDIUM AND EXTENDED RANGE WL TURN TO THE IMPACT OF SEVERAL CLIPPER TYPE SHRTWVS THAT ARE FCST TO MOVE THRU A DEEPENING UPR TROF IN ERN NAMERICA THAT WL BRING A RETURN OF BLO NORMAL TEMPS MOST OF THIS TIME TO THE CWA. WITH THE RETURN OF ARCTIC AIR...LES WL ALSO BE A CONCERN. THU...THE FIRST OF THESE CLIPPER SHRTWVS IS CURRENTLY MOVING E THRU ALBERTA AND IS FCST TO BE NEAR FAR NW LAKE SUP AT 12Z THU BEFORE MOVING TO NEAR THE SAULT AT 00Z FRI TO THE N OF ANOTHER SHRTWV/SFC LO PRES DRIFTING THRU THE LOWER LKS. THE MODELS INDICATE THERE WL BE LTL IF ANY PHASING BTWN THESE SEPARTE DISTURBANCES...SO LINGERING LIGHT SN IN THE WAA/DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THIS NRN SHRTWV SHOULD BE DIMINISHING W-E ON THU MRNG AS ITS ATTENDANT COLD FNT SWEEPS SE AND CLEARS THE CWA BY 18Z THU. NNW H925 WINDS FCST AS HI AS 35 TO 40 KTS UNDER THE SHARP PRES GRADIENT BTWN THE ASSOCIATED SFC LO MOVING INTO SE ONTARIO AND TRAILING ARCTIC HI PRES BLDG THRU SCENTRAL CANADA WILL DRIVE MUCH COLDER AIR INTO THE UPR LKS...DROPPING H85 TEMPS OVER THE UPR LKS TO ARND -20C BY 00Z FRI. BEFORE THIS VERY COLD AIR SURGES INTO THE AREA IN THE AFTN...NOT OUT OF THE QUESTION THERE COULD BE A BIT OF FREEZING DZ MIXED WITH LINGERING LIGHT SN IN THE UPSLOPE AREAS NEAR LK SUP AS SOME OF THE MODELS SHOW THE RELATIVELY SHALLOW MOIST LYR WARMER THAN -10C FOR A COUPLE OF HRS. THE INFLUX OF ARCTIC AIR WL FAVOR FALLING TEMPS AND LES IN THE AFTN. SO INCLUDED A SCHC OF SOME OF THIS WINTRY MIX. BUT STRONG SUBSIDENCE RELATED TO THE VIGOROUS CAA/DNVA/DEEP LYR QVECTOR DVGC IS FCST TO DROP THE INVRN BASE TO BTWN H85-9 DURING THE DAY...WHICH ALONG WITH A NEUTRAL/ACYC LLVL FLOW LIMIT THE INTENSITY OF THE SN SHOWERS DESPITE THE PRESENCE OF THE DGZ WITHIN THE CONVECTIVE LYR. WITH THE STRONG CAA/NEAR SFC DESTABILIZATION AND THE EXPECTED H925 WINDS...WIND GUSTS AT EXPOSED AREAS NEAR LK SUP WL AT LEAST APRCH ADVY CRITERIA AND BRING ABOUT CONSIDERABLE BLOWING SN. SINCE SN AMOUNTS WL BE MARGINAL...DID NOT ISSUE ANY HEADLINES. WL MENTION THE GUSTY WINDS/BLOWING SN IN THE HWO. THU NGT...PERSISTENT COLD BUT SLOWLY DIMINISHING NNW WINDS IN ADVANCE OF SLOWLY APRCHG SFC HI PRES WL BRING CONTINUED LES IN THE FAVORED SN BELTS...BUT AS INVRN BASE SINKS FURTHER W-E UNDER THE LARGER SCALE DNVA/DEEP LYR QVECTOR DVGC AHEAD OF APRCHG SHRTWV RDG AXIS...FOLLOWED TREND OF PREVIOUS FCST TO SHOW DCRSG POPS ESPECIALLY OVER THE W...WHERE THE H925 FLOW WL BECOME MORE SHARPLY ACYC. OVER THE FAR W...THE LES MAY END COMPLETELY BY 12Z WITH FCST INVRN BASE NEAR H95. AS FOR TEMPS...LOWS OVER THE INTERIOR W HALF MAY FALL BLO ZERO IN A FEW SPOTS...BUT CONTINUED NW SFC-H925 FLOW WL FAVOR SOME MODERATION OFF LK SUP AND LIMIT THE COVERAGE OF THE SUB ZERO MINS. FRI...SFC HI PRES IS FCST TO SHIFT FM OVER MN INTO THE LOWER LKS. AS WINDS BACK TO THE W...LINGERING LES OVER THE W WL BECOME CONFINED TO OVER THE KEWEENAW AND END OVER THE E EXCEPT NEAR THE SHORE E OF GRAND MARAIS TOWARD 00Z SAT. ALTHOUGH THE LK CLDS WL BE SHIFTING OFFSHORE...MORE MID/HI CLDS IN ADVANCE OF ANOTHER SHRTWV MOVING SE WITHIN THE NW FLOW ALF WL BE PUSHING INTO THE UPR LKS. FRI NGT/SAT...SHRTWV IS FCST TO SLIDE ESEWD THRU THE UPR LKS. SINCE THIS DISTURBANCE IS FCST TO BE FAIRLY SHEARED OUT WITH ONLY AN AREA OF RELATIVELY WEAK LARGE SCALE FORCING AND MSTR INFLOW WL BE FAIRLY LIMITED...SUSPECT ACCOMPANYING SN WL BE ON THE LIGHT SIDE. ANY LINGERING LIGHT SN OVER THE E ON SAT MRNG WL END WITH ARRIVAL OF LARGER SCALE QVECTOR DVGC/MID LVL DRYING AND GIVE WAY TO SOME LES AS COLDER AIR FOLLOWS THE SHRTWV AND DROPS H85 TEMPS TOWARD -20C AGAIN LATE. BUT MORE DIFFLUENT ACYC H925 FLOW/LO SUBSIDENCE INVRN FCST IN THE H875-9 RANGE WL BE LIMITING FACTORS FOR LES INTENSITY AGAIN. EXTENDED...UNDER A NW FLOW ALF BTWN A MEAN TROF OVER ERN CANADA AND A RDG OVER THE W...ARCTIC HI PRES IS FCST TO SINK SEWD FM WRN CANADA ON SUN INTO UPR MS VALLEY ON MON AND THEN INTO THE OH RIVER VALLEY ON TUE...BRINGING A CONTINUOUS FEED OF CNDN AIR AND H85 TEMPS FALLING AS LO AS -25C BY EARLY NEXT WEEK. A NUMBER OF THE EXTENDED MODELS ARE HINTING A LO PRES WL TAKE SHAPE IN THE MID MS RIVER VALLY ON SUN ON THE LEADING EDGE OF THE INCOMING ARCTIC AIRMASS...BUT INDICATE THE SFC LO WL TRACK ENE FAR ENUF TO THE SE OF UPR MI TO KEEP THE ASSOCIATED PCPN SHIELD TO THE S AS WELL. BUT THE CHILL OF THE INCOMING AIRMASS INDICATES LES WL BE A GOOD BET IN THE FAVORED SN BELTS. THERE MAY BE SOME MODERATION NEXT TUE INTO WED AS THE SW FLOW BTWN THE HI MOVING TOWARD THE MID ATLANTIC COAST AND ANOTHER SHRTWV DROPPING SE THRU SCENTRAL CANADA DRAWS H85 TEMPS IN THE -10 TO -12C RANGE BACK INTO THE UPR LKS. BUT THIS CLIPPER MAY BRING SOME LIGHT SN. AS THE TROF DEEPENS AGAIN FOLLOWING THE PASSAGE OF THIS DISTURBANCE...ANOTHER VERY COLD AIRMASS MAY INVADE LATE NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1202 AM EST WED JAN 28 2015 BASED ON UPSTREAM CLOUDS OVER MUCH OF WI AND MN AND ALSO MID CLOUDS SPREADING ACROSS THE UPPER LAKES FROM ONTARIO...MVFR CLOUD DECK ACROSS MUCH OF WEST AND CENTRAL UPPER MI SHOULD PERSIST THROUGH MUCH OF THE FCST PD AT ALL THE TAF SITES. THERE MAY BE A SLIGHT IMPROVEMENT TO HIGH END MVFR BY WED AFTERNOON WITH INCREASED MIXING FROM SOUTH WINDS. ANOTHER DISTURBANCE MOVING DOWN FROM ONTARIO WILL BRING SOME LIGHT SNOW INTO THE AREA WED EVENING. THE BEST CHANCE FOR IFR CONDITIONS IN SNOW WILL BE AT KCMX WHICH WILL BE IN CLOSER PROXIMITY TO DEEPER MOISTURE AND BETTER FORCING WITH DISTURBANCE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 320 AM EST WED JAN 28 2015 A GALE WATCH HAS BEEN ISSUED FOR MUCH OF LAKE SUPERIOR LATE THURSDAY MORNING INTO THURSDAY NIGHT...WITH N-NNW GALES OF 35-40KTS. EXPECT HIGH PRESSURE CENTERED OVER OHIO THIS MORNING TO SHIFT E AND OFF THE MID ATLANTIC COAST THURSDAY MORNING. A LOW TAKING SHAPE OVER THE N PLAINS WILL MOVE TO AROUND CHICAGO ON THURSDAY...AND INTO N NEW ENGLAND ON FRIDAY...WHILE ANOTHER LOW MOVES FROM S SASKATCHEWAN TO N LAKE SUPERIOR AND QUEBEC. IN THEIR WAKE...EXPECT HIGH PRESSURE OVER S CENTRAL CANADA TO FOLLOW INTO THE UPPER MIDWEST ON FRIDAY...USHERING COLDER AIR INTO THE AREA. AS A RESULT...HEAVY FREEZING SPRAY WILL BE POSSIBLE THURSDAY AFTERNOON THROUGH LATE FRIDAY MORNING. AS THIS HIGH MOVES INTO THE MID ATLANTIC STATES ON SATURDAY...A LOW SHOULD MOVE ACROSS THE UPPER GREAT LAKES. THE LOW WILL THEN PUSH OVER SE ONTARIO ON SUNDAY. N WINDS WILL AGAIN INCREASE TO 20-30KTS SATURDAY-SUNDAY. LOOK FOR A RIDGE TO BUILD OVER W CANADA ON SUNDAY...AND EXTEND A RIDGE INTO ONTARIO JUST N OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM THURSDAY AFTERNOON THROUGH LATE THURSDAY NIGHT FOR LSZ267. GALE WATCH FROM THURSDAY MORNING THROUGH LATE THURSDAY NIGHT FOR LSZ266. GALE WATCH FROM THURSDAY MORNING THROUGH LATE THURSDAY NIGHT FOR LSZ264-265. GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KC AVIATION...VOSS MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
321 AM EST WED JAN 28 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 426 PM EST TUE JAN 27 2015 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER THE CONUS...FEATURING A STRONG RIDGE OVER THE ROCKIES AND A DEEP TROF ALONG THE E COAST. RESULTING NW FLOW INTO THE GREAT LAKES IS QUIETER TODAY THAN YESTERDAY AS SUBTLE SHORTWAVE RIDGING IS JUST UPSTREAM OVER NRN ONTARIO. SO...THERE IS NO PCPN OF NOTE TODAY. THERE HAVE BEEN SOME -SHSN/FLURRIES OFF NRN LAKE MICHIGAN INTO MENOMINEE COUNTY...AND RECENTLY FLURRIES HAVE APPEARED ON KMQT RADAR IMAGERY IN CNTRL UPPER MI. AT THE SFC...HIGH PRES IS CENTERED OVER SRN QUEBEC WITH RIDGE EXTENDING BACK THRU THE UPPER LAKES. DRY AIR ASSOCIATED WITH THE HIGH HAS RESULTED IN A SUNNY DAY OVER ERN UPPER MI...ROUGHLY E OF A MUNISING-ESCANABA LINE. LOW CLOUDS HAVE BEEN PERSISTENT OVER THE REST OF THE AREA...THOUGH PORTIONS OF NW UPPER MI DID HAVE MOSTLY SUNNY SKIES EARLIER TODAY. QUIET WEATHER WILL CONTINUE TONIGHT WITH SHORTWAVE RIDGING PASSING ACROSS THE AREA. MAIN ISSUE WILL BE CLOUD TRENDS AND THE BIG IMPACT THE CLOUDS WILL HAVE ON TEMPS. WITH CLEAR SKIES AND LIGHT/CALM WIND TO START THE EVENING...THE ERN FCST AREA WILL BE COLDEST TONIGHT. LOWERED MINS TO AROUND 0F IN THAT AREA...BUT IT COULD BE 5 OR MORE DEGREES COLDER IF SKIES REMAIN CLEAR THRU THE WHOLE EVENING. OVERNIGHT...THERE WILL BE AN INCREASE IN CLOUDS DUE TO HIGH CLOUDS STREAKING SE WELL AHEAD OF THE NEXT SHORTWAVE MOVING ACROSS THE SRN CANADIAN ROCKIES AND POSSIBLY FROM LOW CLOUDS ADVECTING NE IN DEVELOPING SW FLOW. THIS WILL PUT THE BRAKES ON COOLING AND PROBABLY LEAD TO TEMPS RISING SOME OVERNIGHT. ACROSS THE REST OF THE FCST AREA...THE EXPANSE OF LOW CLOUDS EXTENDING W...SW AND S OVER MUCH OF MN AND WI SUGGESTS CLOUDS WILL DOMINATE FOR MUCH OF THE NIGHT UNDER LOW-LEVEL S TO SW WINDS. EVEN IF LOW CLOUDS CLEAR OUT IN SOME AREAS...HIGH AND MID CLOUDS WILL BE OVERSPREADING THE AREA. LOWS SHOULD GENERALLY BE IN THE 15-20F RANGE. ON WED....ONE SHORTWAVE WILL MOVE FROM THE SRN CANADIAN ROCKIES INTO THE DAKOTAS/MANITOBA WHILE A SECOND MOVES FROM WY/CO TO THE CNTRL PLAINS. AHEAD OF THE NRN WAVE...WAA/ISENTROPIC ASCENT WILL STRENGTHEN AND SHIFT ESE THRU THE DAY UNDERNEATH RIGHT ENTRANCE OF UPPER JET. WITH THE FOCUS OF MOIST ISENTROPIC ASCENT JUST TO THE N AND WITH DRIER AIR HOLDING ON AT LOW LEVELS...THE MAIN STREAK OF SNOW WILL REMAIN N OF HERE WED AFTN. MODEL AGREEMENT IS IN EXCELLENT AGREEMENT ON THIS POINT. HOWEVER...THERE IS SOME UNCERTAINTY IN WHETHER THE SRN EDGE OF THE SNOW MAY CLIP THE AREA. BASED ON STRENGTH OF ISENTROPIC ASCENT AND TEMP/MOISTURE PROFILES ON FCST SOUNDINGS...THE KEWEENAW AND FAR ERN FCST AREA MAY GET CLIPPED BY A LITTLE -SN. INCLUDED ONLY SCHC/LOW CHC POPS TO REFLECT THIS POTENTIAL. OTHERWISE...EXPECT A WARMER DAY WITH HIGHS IN THE UPPER 20S/LWR 30S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 313 PM EST TUE JAN 27 2015 AN UPPER RIDGE OVER THE WESTERN COAST OF NORTH AMERICA AND AN UPPER LOW OVER HUDSON BAY WILL KEEP NORTHWEST FLOW OVER THE UPPER GREAT LAKES REGION FOR MUCH OF THE LONG TERM PERIOD. THIS WILL LEAD TO SEVERAL SHORTWAVES DROPPING SOUTHEAST ACROSS THE REGION...WHILE THE UPPER LOW OVER HUDSON BAY GRADUALLY SINKS SOUTH TOWARDS THE AREA. THUS...EXPECT GRADUALLY COOLING TEMPERATURES THROUGH EARLY NEXT WEEK. THREE PIECES OF ENERGY WITHIN THE LARGER SHORTWAVE TROUGH MOVING THROUGH THE UPPER GREAT LAKES REGION WEDNESDAY NIGHT AND THURSDAY WILL BE DRIVING THE WEATHER FOR THE START OF THE LONG TERM PERIOD. THE SOUTHERN TWO WAVES WILL BE SUPPORTING THE SURFACE LOW MOVING THROUGH SOUTHERN WISCONSIN AND THE INVERTED TROUGH CROSSING THE UPPER GREAT LAKES REGION. AT THE START OF THE LONG TERM PERIOD...EXPECT THE HEAVIEST PRECIPITATION TO BE ONGOING OVER NORTHERN ONTARIO AND FAR NORTHERN LAKE SUPERIOR...WHILE THERE WILL BE SOME SNOW OVER EASTERN UPPER MICHIGAN TIED TO THE NOSE OF THE 850-700MB WARM AIR ADVECTION INTERACTING WITH THE DEEPER MOISTURE. THINKING MUCH OF THE REST OF THE AREA WILL BE SEEING LIMITED PRECIPITATION CHANCES WITH THE POCKET OF DRY AIR BETWEEN 925-750MB. THEN AS THE 850-700MB TROUGH SWEEPS SOUTHEAST THROUGH THE AREA THROUGH THE NIGHT...EXPECT SNOW TO QUICKLY SPREAD INTO THE AREA THROUGH THE EVENING/OVERNIGHT HOURS. WITH THAT INITIAL PRECIPITATION STAYING TO THE NORTH OF THE LAND AREA INITIALLY...HAVE TRENDED QPF/SNOW AMOUNTS DOWN SLIGHTLY OVER THE WEST/CENTRAL (1-2IN). NORTHEAST OF A LINE FROM HOUGHTON TO MANISTIQUE...HAVE AMOUNTS IN THE 2-3.5 INCH RANGE AND WILL CONTINUE TO MENTION IN THE HWO FOR THOSE AREAS. AS THE DEEPER MOISTURE DEPARTS THURSDAY MORNING...WILL SEE THE SNOW DIMINISH...BUT THINK THERE WILL BE ENOUGH TERRAIN INFLUENCE TO HELP KEEP SNOW SHOWERS IN THE NORTH-NORTHWESTERLY WIND SNOW BELTS UNTIL THE COLD AIR ARRIVES THURSDAY AFTERNOON AND INCREASES DELTA-T VALUES TOWARDS THE LOW 20S BY THURSDAY EVENING. THERE ARE HINTS OF LIMITED ICE CRYSTALS (AND THUS FREEZING DRIZZLE) OVER THE WEST AS THAT DEEP MOISTURE DEPARTS...BUT THINK IT IS TOO MARGINAL TO MENTION AT THIS POINT. WITH THAT COLD AIR ARRIVING FROM NORTHWEST TO SOUTHEAST ON THURSDAY AFTERNOON/EVENING...SHOULD SEE LAKE EFFECT COVERAGE INCREASING DURING THAT TIME FRAME. WILL TREND POPS UP TO LIKELY/DEFINITE VALUES FOR THE FAVORED NORTHWEST WIND SNOW BELTS FOR THURSDAY NIGHT. WHILE SNOW IS EXPECTED...THERE ARE A COUPLE LIMITING FACTORS FOR HIGHER SNOWFALL AMOUNTS. FIRST...THE APPROACHING HIGH PRESSURE RIDGE WILL KEEP THE SUBSIDENCE INVERSION AROUND 5KFT THROUGH THE PERIOD. WHILE MUCH OF THE CLOUD WILL BE IN OR JUST ABOVE THE DGZ...THINK THE FRACTURING OF THE FLAKES FROM THE GUSTY WINDS WILL KEEP SNOW RATIOS LOWER (BUT BE BETTER AT REDUCING VISIBILITIES). THUS...HAVE SNOWFALL AMOUNTS OF 1-4 INCHES IN THE FAVORED SNOW BELTS DURING THAT PERIOD. AS THE HIGH MOVES JUST SOUTH OF THE AREA ON FRIDAY...EXPECT WINDS TO BACK TOWARDS THE WEST AND LOWER THE SUBSIDENCE INVERSION TOWARDS 4KFT. THEREFORE...WILL GRADUALLY DIMINISH PRECIPITATION CHANCES THROUGH FRIDAY AS WINDS BACK TO THE SOUTHWEST ON FRIDAY NIGHT. THE NEXT CLIPPER WILL SWEEP ACROSS THE AREA SATURDAY AND DRAG A WEAK SURFACE TROUGH WITH IT. STILL SOME DIFFERENCES IN THE TIMING WITH THIS FEATURE...SO WILL GO WITH LOW END CHANCE POPS SPREADING ACROSS THE CWA ON SATURDAY. OVERALL...LOOKS LIKE JUST A QUICK DUSTING OF SNOW WITH THIS FEATURE. BEHIND THE TROUGH...COLD AIR WILL FILTER BACK INTO THE UPPER GREAT LAKES REGION AND BRING ANOTHER PERIOD OF LAKE EFFECT FOR THE NORTH-NORTHWEST WIND SNOWBELTS. ONCE AGAIN...THE HIGH PRESSURE RIDGE NOSING EAST INTO THE AREA WILL KEEP THE SUBSIDENCE INVERSION AROUND 5KFT AND KEEP THE LAKE EFFECT AMOUNTS ON THE LIGHT SIDE. ONE ITEM TO WATCH IS THE POTENTIAL FOR A WEAK SHORTWAVE SLIDING ACROSS THE AREA ON MONDAY. THERE ARE HINTS THAT THIS MAY RAISE INVERSION HEIGHTS TOWARDS 7-10KFT...WHICH WOULD PROVIDE THE POTENTIAL FOR MODERATE LAKE EFFECT. WHEN THAT OCCURS...WITH ANOTHER SURGE OF COLD AIR (850MB TEMPS FALLING TO THE MID -20S) THE CLOUD WILL BE WELL ABOVE THE DGZ AND SUPPORT SMALL FLAKES THAT ARE HIGHLY EFFICIENT AT REDUCING VISIBILITY. WITH THE HIGH MOVING SOUTHEAST FROM THE NORTHERN PLAINS ON MONDAY MORNING TO THE OHIO RIVER VALLEY ON TUESDAY...EXPECT GRADUALLY BACKING WINDS OVER LAKE SUPERIOR AND WILL FOLLOW THAT IDEA FOR AT LEAST LIKELY POPS FOR THE FAVORED WIND DIRECTIONS THROUGH TUESDAY (WINDS NEAR WESTERLY BY TUESDAY EVENING). WON/T MENTION IN THE HWO AT THIS POINT...AS AMOUNTS WILL BE ON THE LOW SIDE...BUT MAY NEED TO ADDRESS THE END OF THE WEEK LAKE EFFECT AND THE SUN-TUE LAKE EFFECT IN THE FUTURE DUE TO THE LIKELY LOW VISIBILITIES IN THE STRONGER BANDS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1202 AM EST WED JAN 28 2015 BASED ON UPSTREAM CLOUDS OVER MUCH OF WI AND MN AND ALSO MID CLOUDS SPREADING ACROSS THE UPPER LAKES FROM ONTARIO...MVFR CLOUD DECK ACROSS MUCH OF WEST AND CENTRAL UPPER MI SHOULD PERSIST THROUGH MUCH OF THE FCST PD AT ALL THE TAF SITES. THERE MAY BE A SLIGHT IMPROVEMENT TO HIGH END MVFR BY WED AFTERNOON WITH INCREASED MIXING FROM SOUTH WINDS. ANOTHER DISTURBANCE MOVING DOWN FROM ONTARIO WILL BRING SOME LIGHT SNOW INTO THE AREA WED EVENING. THE BEST CHANCE FOR IFR CONDITIONS IN SNOW WILL BE AT KCMX WHICH WILL BE IN CLOSER PROXIMITY TO DEEPER MOISTURE AND BETTER FORCING WITH DISTURBANCE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 320 AM EST WED JAN 28 2015 A GALE WATCH HAS BEEN ISSUED FOR MUCH OF LAKE SUPERIOR LATE THURSDAY MORNING INTO THURSDAY NIGHT...WITH N-NNW GALES OF 35-40KTS. EXPECT HIGH PRESSURE CENTERED OVER OHIO THIS MORNING TO SHIFT E AND OFF THE MID ATLANTIC COAST THURSDAY MORNING. A LOW TAKING SHAPE OVER THE N PLAINS WILL MOVE TO AROUND CHICAGO ON THURSDAY...AND INTO N NEW ENGLAND ON FRIDAY...WHILE ANOTHER LOW MOVES FROM S SASKATCHEWAN TO N LAKE SUPERIOR AND QUEBEC. IN THEIR WAKE...EXPECT HIGH PRESSURE OVER S CENTRAL CANADA TO FOLLOW INTO THE UPPER MIDWEST ON FRIDAY...USHERING COLDER AIR INTO THE AREA. AS A RESULT...HEAVY FREEZING SPRAY WILL BE POSSIBLE THURSDAY AFTERNOON THROUGH LATE FRIDAY MORNING. AS THIS HIGH MOVES INTO THE MID ATLANTIC STATES ON SATURDAY...A LOW SHOULD MOVE ACROSS THE UPPER GREAT LAKES. THE LOW WILL THEN PUSH OVER SE ONTARIO ON SUNDAY. N WINDS WILL AGAIN INCREASE TO 20-30KTS SATURDAY-SUNDAY. LOOK FOR A RIDGE TO BUILD OVER W CANADA ON SUNDAY...AND EXTEND A RIDGE INTO ONTARIO JUST N OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...VOSS MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1203 AM EST WED JAN 28 2015 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 426 PM EST TUE JAN 27 2015 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN AMPLIFIED PATTERN OVER THE CONUS...FEATURING A STRONG RIDGE OVER THE ROCKIES AND A DEEP TROF ALONG THE E COAST. RESULTING NW FLOW INTO THE GREAT LAKES IS QUIETER TODAY THAN YESTERDAY AS SUBTLE SHORTWAVE RIDGING IS JUST UPSTREAM OVER NRN ONTARIO. SO...THERE IS NO PCPN OF NOTE TODAY. THERE HAVE BEEN SOME -SHSN/FLURRIES OFF NRN LAKE MICHIGAN INTO MENOMINEE COUNTY...AND RECENTLY FLURRIES HAVE APPEARED ON KMQT RADAR IMAGERY IN CNTRL UPPER MI. AT THE SFC...HIGH PRES IS CENTERED OVER SRN QUEBEC WITH RIDGE EXTENDING BACK THRU THE UPPER LAKES. DRY AIR ASSOCIATED WITH THE HIGH HAS RESULTED IN A SUNNY DAY OVER ERN UPPER MI...ROUGHLY E OF A MUNISING-ESCANABA LINE. LOW CLOUDS HAVE BEEN PERSISTENT OVER THE REST OF THE AREA...THOUGH PORTIONS OF NW UPPER MI DID HAVE MOSTLY SUNNY SKIES EARLIER TODAY. QUIET WEATHER WILL CONTINUE TONIGHT WITH SHORTWAVE RIDGING PASSING ACROSS THE AREA. MAIN ISSUE WILL BE CLOUD TRENDS AND THE BIG IMPACT THE CLOUDS WILL HAVE ON TEMPS. WITH CLEAR SKIES AND LIGHT/CALM WIND TO START THE EVENING...THE ERN FCST AREA WILL BE COLDEST TONIGHT. LOWERED MINS TO AROUND 0F IN THAT AREA...BUT IT COULD BE 5 OR MORE DEGREES COLDER IF SKIES REMAIN CLEAR THRU THE WHOLE EVENING. OVERNIGHT...THERE WILL BE AN INCREASE IN CLOUDS DUE TO HIGH CLOUDS STREAKING SE WELL AHEAD OF THE NEXT SHORTWAVE MOVING ACROSS THE SRN CANADIAN ROCKIES AND POSSIBLY FROM LOW CLOUDS ADVECTING NE IN DEVELOPING SW FLOW. THIS WILL PUT THE BRAKES ON COOLING AND PROBABLY LEAD TO TEMPS RISING SOME OVERNIGHT. ACROSS THE REST OF THE FCST AREA...THE EXPANSE OF LOW CLOUDS EXTENDING W...SW AND S OVER MUCH OF MN AND WI SUGGESTS CLOUDS WILL DOMINATE FOR MUCH OF THE NIGHT UNDER LOW-LEVEL S TO SW WINDS. EVEN IF LOW CLOUDS CLEAR OUT IN SOME AREAS...HIGH AND MID CLOUDS WILL BE OVERSPREADING THE AREA. LOWS SHOULD GENERALLY BE IN THE 15-20F RANGE. ON WED....ONE SHORTWAVE WILL MOVE FROM THE SRN CANADIAN ROCKIES INTO THE DAKOTAS/MANITOBA WHILE A SECOND MOVES FROM WY/CO TO THE CNTRL PLAINS. AHEAD OF THE NRN WAVE...WAA/ISENTROPIC ASCENT WILL STRENGTHEN AND SHIFT ESE THRU THE DAY UNDERNEATH RIGHT ENTRANCE OF UPPER JET. WITH THE FOCUS OF MOIST ISENTROPIC ASCENT JUST TO THE N AND WITH DRIER AIR HOLDING ON AT LOW LEVELS...THE MAIN STREAK OF SNOW WILL REMAIN N OF HERE WED AFTN. MODEL AGREEMENT IS IN EXCELLENT AGREEMENT ON THIS POINT. HOWEVER...THERE IS SOME UNCERTAINTY IN WHETHER THE SRN EDGE OF THE SNOW MAY CLIP THE AREA. BASED ON STRENGTH OF ISENTROPIC ASCENT AND TEMP/MOISTURE PROFILES ON FCST SOUNDINGS...THE KEWEENAW AND FAR ERN FCST AREA MAY GET CLIPPED BY A LITTLE -SN. INCLUDED ONLY SCHC/LOW CHC POPS TO REFLECT THIS POTENTIAL. OTHERWISE...EXPECT A WARMER DAY WITH HIGHS IN THE UPPER 20S/LWR 30S. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 313 PM EST TUE JAN 27 2015 AN UPPER RIDGE OVER THE WESTERN COAST OF NORTH AMERICA AND AN UPPER LOW OVER HUDSON BAY WILL KEEP NORTHWEST FLOW OVER THE UPPER GREAT LAKES REGION FOR MUCH OF THE LONG TERM PERIOD. THIS WILL LEAD TO SEVERAL SHORTWAVES DROPPING SOUTHEAST ACROSS THE REGION...WHILE THE UPPER LOW OVER HUDSON BAY GRADUALLY SINKS SOUTH TOWARDS THE AREA. THUS...EXPECT GRADUALLY COOLING TEMPERATURES THROUGH EARLY NEXT WEEK. THREE PIECES OF ENERGY WITHIN THE LARGER SHORTWAVE TROUGH MOVING THROUGH THE UPPER GREAT LAKES REGION WEDNESDAY NIGHT AND THURSDAY WILL BE DRIVING THE WEATHER FOR THE START OF THE LONG TERM PERIOD. THE SOUTHERN TWO WAVES WILL BE SUPPORTING THE SURFACE LOW MOVING THROUGH SOUTHERN WISCONSIN AND THE INVERTED TROUGH CROSSING THE UPPER GREAT LAKES REGION. AT THE START OF THE LONG TERM PERIOD...EXPECT THE HEAVIEST PRECIPITATION TO BE ONGOING OVER NORTHERN ONTARIO AND FAR NORTHERN LAKE SUPERIOR...WHILE THERE WILL BE SOME SNOW OVER EASTERN UPPER MICHIGAN TIED TO THE NOSE OF THE 850-700MB WARM AIR ADVECTION INTERACTING WITH THE DEEPER MOISTURE. THINKING MUCH OF THE REST OF THE AREA WILL BE SEEING LIMITED PRECIPITATION CHANCES WITH THE POCKET OF DRY AIR BETWEEN 925-750MB. THEN AS THE 850-700MB TROUGH SWEEPS SOUTHEAST THROUGH THE AREA THROUGH THE NIGHT...EXPECT SNOW TO QUICKLY SPREAD INTO THE AREA THROUGH THE EVENING/OVERNIGHT HOURS. WITH THAT INITIAL PRECIPITATION STAYING TO THE NORTH OF THE LAND AREA INITIALLY...HAVE TRENDED QPF/SNOW AMOUNTS DOWN SLIGHTLY OVER THE WEST/CENTRAL (1-2IN). NORTHEAST OF A LINE FROM HOUGHTON TO MANISTIQUE...HAVE AMOUNTS IN THE 2-3.5 INCH RANGE AND WILL CONTINUE TO MENTION IN THE HWO FOR THOSE AREAS. AS THE DEEPER MOISTURE DEPARTS THURSDAY MORNING...WILL SEE THE SNOW DIMINISH...BUT THINK THERE WILL BE ENOUGH TERRAIN INFLUENCE TO HELP KEEP SNOW SHOWERS IN THE NORTH-NORTHWESTERLY WIND SNOW BELTS UNTIL THE COLD AIR ARRIVES THURSDAY AFTERNOON AND INCREASES DELTA-T VALUES TOWARDS THE LOW 20S BY THURSDAY EVENING. THERE ARE HINTS OF LIMITED ICE CRYSTALS (AND THUS FREEZING DRIZZLE) OVER THE WEST AS THAT DEEP MOISTURE DEPARTS...BUT THINK IT IS TOO MARGINAL TO MENTION AT THIS POINT. WITH THAT COLD AIR ARRIVING FROM NORTHWEST TO SOUTHEAST ON THURSDAY AFTERNOON/EVENING...SHOULD SEE LAKE EFFECT COVERAGE INCREASING DURING THAT TIME FRAME. WILL TREND POPS UP TO LIKELY/DEFINITE VALUES FOR THE FAVORED NORTHWEST WIND SNOW BELTS FOR THURSDAY NIGHT. WHILE SNOW IS EXPECTED...THERE ARE A COUPLE LIMITING FACTORS FOR HIGHER SNOWFALL AMOUNTS. FIRST...THE APPROACHING HIGH PRESSURE RIDGE WILL KEEP THE SUBSIDENCE INVERSION AROUND 5KFT THROUGH THE PERIOD. WHILE MUCH OF THE CLOUD WILL BE IN OR JUST ABOVE THE DGZ...THINK THE FRACTURING OF THE FLAKES FROM THE GUSTY WINDS WILL KEEP SNOW RATIOS LOWER (BUT BE BETTER AT REDUCING VISIBILITIES). THUS...HAVE SNOWFALL AMOUNTS OF 1-4 INCHES IN THE FAVORED SNOW BELTS DURING THAT PERIOD. AS THE HIGH MOVES JUST SOUTH OF THE AREA ON FRIDAY...EXPECT WINDS TO BACK TOWARDS THE WEST AND LOWER THE SUBSIDENCE INVERSION TOWARDS 4KFT. THEREFORE...WILL GRADUALLY DIMINISH PRECIPITATION CHANCES THROUGH FRIDAY AS WINDS BACK TO THE SOUTHWEST ON FRIDAY NIGHT. THE NEXT CLIPPER WILL SWEEP ACROSS THE AREA SATURDAY AND DRAG A WEAK SURFACE TROUGH WITH IT. STILL SOME DIFFERENCES IN THE TIMING WITH THIS FEATURE...SO WILL GO WITH LOW END CHANCE POPS SPREADING ACROSS THE CWA ON SATURDAY. OVERALL...LOOKS LIKE JUST A QUICK DUSTING OF SNOW WITH THIS FEATURE. BEHIND THE TROUGH...COLD AIR WILL FILTER BACK INTO THE UPPER GREAT LAKES REGION AND BRING ANOTHER PERIOD OF LAKE EFFECT FOR THE NORTH-NORTHWEST WIND SNOWBELTS. ONCE AGAIN...THE HIGH PRESSURE RIDGE NOSING EAST INTO THE AREA WILL KEEP THE SUBSIDENCE INVERSION AROUND 5KFT AND KEEP THE LAKE EFFECT AMOUNTS ON THE LIGHT SIDE. ONE ITEM TO WATCH IS THE POTENTIAL FOR A WEAK SHORTWAVE SLIDING ACROSS THE AREA ON MONDAY. THERE ARE HINTS THAT THIS MAY RAISE INVERSION HEIGHTS TOWARDS 7-10KFT...WHICH WOULD PROVIDE THE POTENTIAL FOR MODERATE LAKE EFFECT. WHEN THAT OCCURS...WITH ANOTHER SURGE OF COLD AIR (850MB TEMPS FALLING TO THE MID -20S) THE CLOUD WILL BE WELL ABOVE THE DGZ AND SUPPORT SMALL FLAKES THAT ARE HIGHLY EFFICIENT AT REDUCING VISIBILITY. WITH THE HIGH MOVING SOUTHEAST FROM THE NORTHERN PLAINS ON MONDAY MORNING TO THE OHIO RIVER VALLEY ON TUESDAY...EXPECT GRADUALLY BACKING WINDS OVER LAKE SUPERIOR AND WILL FOLLOW THAT IDEA FOR AT LEAST LIKELY POPS FOR THE FAVORED WIND DIRECTIONS THROUGH TUESDAY (WINDS NEAR WESTERLY BY TUESDAY EVENING). WON/T MENTION IN THE HWO AT THIS POINT...AS AMOUNTS WILL BE ON THE LOW SIDE...BUT MAY NEED TO ADDRESS THE END OF THE WEEK LAKE EFFECT AND THE SUN-TUE LAKE EFFECT IN THE FUTURE DUE TO THE LIKELY LOW VISIBILITIES IN THE STRONGER BANDS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1202 AM EST WED JAN 28 2015 BASED ON UPSTREAM CLOUDS OVER MUCH OF WI AND MN AND ALSO MID CLOUDS SPREADING ACROSS THE UPPER LAKES FROM ONTARIO...MVFR CLOUD DECK ACROSS MUCH OF WEST AND CENTRAL UPPER MI SHOULD PERSIST THROUGH MUCH OF THE FCST PD AT ALL THE TAF SITES. THERE MAY BE A SLIGHT IMPROVEMENT TO HIGH END MVFR BY WED AFTERNOON WITH INCREASED MIXING FROM SOUTH WINDS. ANOTHER DISTURBANCE MOVING DOWN FROM ONTARIO WILL BRING SOME LIGHT SNOW INTO THE AREA WED EVENING. THE BEST CHANCE FOR IFR CONDITIONS IN SNOW WILL BE AT KCMX WHICH WILL BE IN CLOSER PROXIMITY TO DEEPER MOISTURE AND BETTER FORCING WITH DISTURBANCE. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 426 PM EST TUE JAN 27 2015 WINDS WILL REMAIN UNDER 20KT TONIGHT/WED. LOW PRES WILL THEN TRACK FROM THE MID AND UPPER MISSISSIPPI VALLEY WED EVENING TO THE LOWER LAKES BY LATE THU EVENING. AHEAD OF THE LOW...S WINDS WILL INCREASE FOR A TIME WED NIGHT...MAINLY OVER ERN LAKE SUPERIOR WHERE WINDS WILL REACH 20-30KT. BEHIND THE LOW ON THU...N TO NW WINDS WILL INCREASE TO 20-30KT OVER WRN LAKE SUPERIOR. OVER THE CNTRL AND ERN LAKE...WINDS WILL INCREASE TO GALE FORCE FOR THU AFTN AND NIGHT. COMBINATION OF MUCH COLDER AIR/STRONG WINDS AND BUILDING WAVES WILL LEAD TO HVY FREEZING SPRAY THU AFTN UNTIL LATE FRI MORNING WHEN WINDS/WAVES DIMINISH WITH THE CLOSER APPROACH OF CANADIAN HIGH PRES. AFTER A PERIOD OF LIGHTER WINDS MOSTLY UNDER 20KT FRI INTO SAT MORNING...N WINDS WILL INCREASE TO 20-30KT LATER SAT INTO SUN IN THE WAKE OF A LOW PRES TROUGH. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...SRF AVIATION...VOSS MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS DULUTH MN
353 AM CST WED JAN 28 2015 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 353 AM CST WED JAN 28 2015 LOW PRESSURE WAS ORGANIZING IN THE DAKOTAS AT 08Z WITH A FRONTAL BOUNDARY EXTENDING NORTHEASTWARD INTO SOUTHERN MANITOBA AND INTO NW ONTARIO. IN THE WAA AHEAD OF THIS SYSTEM...SOME LIGHT SNOW WAS FALLING OVER THE ARROWHEAD WITH LITTLE ACCUMULATION. NORTH OF THE CANADIAN BORDER...SOME LIGHT FREEZING RAIN WAS OCCURRING RIGHT NEAR THE FRONT FROM WINNIPEG TO NEAR DRYDEN. LATEST SHORT TERM HRRR AND RAP KEEP THIS FREEZING RAIN NORTH OF THE BORDER. THE LIGHT SNOW OVER THE ARROWHEAD IS EXPECTED TO SLOWLY END BY NOON. LITTLE ADDITIONAL ACCUMULATION IS ANTICIPATED. BY THIS AFTERNOON...THE SFC LOW MOVES EASTWARD WITH THE LOW CENTER BEGINS TO REORGANIZE AND DRIFT INTO SOUTHWEST IOWA BY 00Z THURSDAY. MEANWHILE...A MID LEVEL LONG WAVE TROF MOVES OVER THE WESTERN GREAT LAKES. SOME MODEL DIFFERENCES BEGIN TO REVEL THEMSELVES WITH RESPECT TO QPF PLACEMENT AND THE AMOUNT OF COLD AIR FORECAST TO DROP INTO THE FORECAST AREA. THE GFS IS THE MOST ROBUST AND FURTHEST SOUTH WHILE THE ECMWF HAS LIMITED QPF AND KEEPS IT NEAR THE CANADIAN BORDER. HAVE USED A BLENDED APPROACH AND KEPT POPS TO THE NORTHERN HALF OF THE FORECAST AREA BY LATE AFTERNOON. PRECIPITATION TYPE WILL BE ALL SNOW. LATEST FORECAST SOUNDINGS ARE NOT SUPPORTING THE MENTION OF FREEZING RAIN OR FREEZING DRIZZLE AND HAVE REMOVED. TONIGHT...THE MID LEVEL LONG WAVE TROF MOVES EAST OF THE FORECAST AREA BY 12Z THURSDAY. THIS PUSHES THE SFC LOW EAST OF THE AREA AS WELL. BEHIND THIS SYSTEM...A TIGHTENING PRESSURE GRADIENT MOVES OVER THE WESTERN GREAT LAKES AS HIGH PRESSURE BUILDS INTO THE WESTERN DAKOTAS. MADE SOME MINOR CHANGES TO THE POPS AND THEIR TIMING ACROSS THE AREA...WITH THE SNOW ENDING LATE TONIGHT OVER THE SOUTHWEST PORTION OF THE FORECAST AREA TO THE TWIN PORTS LATE TONIGHT. FORECAST SOUNDINGS INDICATE THAT THE PRECIPITATION TYPE WILL BE ALL SNOW AND HAVE REMOVED THE MENTION FREEZING RAIN/FREEZING DRIZZLE AND SLEET. SNOW AMOUNTS WILL BE LIGHT WITH THE HIGHEST AMOUNTS OF AROUND ONE HALF INCH FOUND ALONG THE CANADIAN BORDER. ON THURSDAY...ONLY MADE SOME MINOR CHANGES TO THE POPS AND WEATHER AS MODELS ARE IN VERY GOOD AGREEMENT. WILL STILL HAVE GUSTY WINDS AS THE TIGHT PRESSURE GRADIENT REMAINS UNTIL LATE AFTERNOON WHEN THE AFOREMENTIONED HIGH PRESSURE MOVES INTO THE RED RIVER VALLEY. A NW WIND OVER LAKE SUPERIOR AND CAA WILL LEAD TO SOME LAKE EFFECT SNOW ALONG THE HIGHER TERRAIN OF THE SOUTH SHORE. SNOW AMOUNTS WILL BE LIGHT HOWEVER AS DEEP COLD AIR IS LACKING UNTIL LATE AFTERNOON. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 353 AM CST WED JAN 28 2015 MUCH COLDER AIR ON THE WAY FOR THIS WEEKEND WITH A CHANCE FOR SNOW FROM...YOU GUESSED IT...ANOTHER WEAK CLIPPER SYSTEM. THE LARGE SCALE PATTERN WILL UNDERGO SOME CHANGES THROUGH THE LONG TERM THAT WILL /AT LEAST TEMPORARILY/ PUT A STOP TO WHAT HAS BEEN A LONG PERIOD OF WEAK /AND FRANKLY DISAPPOINTING FOR SNOW LOVERS/ CLIPPERS. TEMPERATURES WILL DROP FROM WHAT HAS BEEN A VERY MILD PATTERN TO A COLDER REGIME...ENDING THE LAST WEEK OF JANUARY WITH TEMPS SIMILAR TO THE FIRST WEEK OF THE MONTH. ON THE SYNOPTIC SCALE A SERIES OF STRONG ARCTIC AIR MASSES WILL DROP DOWN INTO THE NORTHERN PLAINS AND UPPER MIDWEST. LATE THIS WEEK AN AREA OF HIGH PRESSURE WILL MOVE OVER THE AREA THURSDAY NIGHT FOLLOWED BY A WEAK CLIPPER ON FRIDAY/FRIDAY NIGHT. THEN LATE IN THE WEEKEND A DEEP LONGWAVE TROUGH AT MID-LEVELS WILL DESCEND OVER THE MIDWEST LEADING TO VERY COLD AIR ALOFT...850MB TEMPS APPROACHING THE COLDEST 10 PERCENT OF CLIMATOLOGY IN THE MID -20S C /COMPARED TO 00Z TODAY WHEN THEY WERE IN THE WARMEST 10 PERCENT OF CLIMO AT AROUND 0C/. BEST CHANCE FOR SNOWFALL ACROSS THE REGION WILL BE LATE FRIDAY AFTERNOON INTO FRIDAY NIGHT A CLIPPER MOVES ACROSS. GFS AND ECMWF IN GOOD AGREEMENT ON TIMING...WITH ECMWF PESSIMISTIC ON INTENSITY AND GFS A LITTLE STRONGER WITH A DEEPER MOISTURE PROFILE. GEM WAS SLOWER AND NOT AS INTENSE OVERALL...BUT THIS WAS A PRETTY BIG CHANGE FROM 12Z GEM WHICH WAS FASTER AND MUCH MORE AGGRESSIVE ON PRECIP. AT THIS POINT IT LOOKS LIKE A QUICK INCH OR TWO FOR NORTHERN MINNESOTA NORTH OF HIGHWAY TWO. OTHERWISE NO SIGNIFICANT CHANCES FOR PRECIP IN THE SEVEN DAY FOR MUCH OF THE REGION...WITH THE EXCEPTION OF LAKE EFFECT SNOWFALL ALONG PORTIONS OF THE SOUTH SHORE OF LAKE SUPERIOR. LAKE EFFECT SNOWFALL WILL BE PRESENT THROUGH MUCH OF THE LONG TERM PERIOD. ON THURSDAY NIGHT CONDITIONS WILL BE GOOD FOR LAKE EFFECT SNOWFALL ALONG THE HIGHER TERRAIN OF IRON/ASHLAND COUNTIES WITH STEEP LOW LEVEL LAPSE RATES THROUGH 850MB AND GREAT NORTH/NORTHWEST FLOW OVER THE LAKE. ICE COVERAGE ON THE SOUTH SHORE MAY LIMIT THE INTENSITY OF LAKE EFFECT SNOWFALL...AND OPTED TO LEAVE NORTHERN BAYFIELD COUNTY OUT OF HIGHER CHANCES FOR LAKE EFFECT SNOWFALL DUE TO WHAT WOULD BE A VERY LIMITED FETCH LENGTH. LOW LEVEL MOISTURE WILL ALSO BE A FACTOR AS NAM/GFS/ECMWF DEPICT A NEAR-SURFACE DRY LAYER...SO IT MAY TAKE A WHILE TO SATURATE LOW LEVELS AND THUS LIMIT SNOWFALL AMOUNTS. LAKE EFFECT WILL TAPER OFF AS HIGH PRESSURE MOVES OVER LAKE SUPERIOR ON FRIDAY AFTERNOON...BUT RAMP BACK UP AGAIN ON SATURDAY AND THROUGH ABOUT TUESDAY DUE TO THE VERY COLD AIRMASS THAT WILL BE IN PLACE. TEMPS WILL BE ON A DOWNWARD TREND...AND HAVE ADJUSTED SOME OF THE USUAL COLD SPOTS A LITTLE COLDER THAN INITIAL GUIDANCE TO ACCOUNT FOR THE ARCTIC HIGHS THAT WILL BE OVER NORTHEASTERN MINNESOTA IN THE LONG TERM. HIGHS IN THE MID TEENS TO MID 20S ON SATURDAY...THEN THE SINGLE DIGITS ON SUNDAY AND MONDAY BEFORE RECOVERING TO THE TEENS TUESDAY. LOWS NEAR ZERO TO TEN OR MORE BELOW ZERO ON THURSDAY NIGHT...MILD FRIDAY NIGHT DUE TO WEAK SOUTHERLY WINDS...THEN 0 TO -15 SATURDAY NIGHT AND 10 TO 20 BELOW ZERO ON SUNDAY NIGHT. MONDAY MORNING WILL BE THE COLDEST PERIOD IN THE LONG TERM WITH WIND CHILL VALUES OF 25 TO 35 BELOW ZERO...AND COLD SPOTS IN THE TIP OF THE ARROWHEAD REGION NEAR 40 BELOW ZERO. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1140 PM CST TUE JAN 27 2015 MVFR CEILINGS WERE ADVANCING NORTH THROUGH KFOZ HEADING TOWARD KINL. AN AREA OF VFR CONDITIONS ALSO EXTENDED FROM KINL THROUGH KTWM INTO KHYR. THE RAP SHOWS VFR CEILINGS WILL PREVAIL OVER EASTERN PORTIONS OF THE NORTHLAND FOR A TIME TONIGHT...BUT SHOULD LOWER ON WEDNESDAY AS LOW LEVEL WAA STRENGTHENS AGAIN. THE FGEN BAND OF SNOW OVER FAR NORTHEAST MINNESOTA HAS DIMINISHED THIS EVENING AND WE EXPECT SOME SPOTTY SNOW OVERNIGHT. AN AREA OF LOW PRESSURE WILL MOVE INTO THE AREA ON WEDNESDAY AND WILL BRING A THREAT FOR SOME MIXED PRECIPITATION TO THE AREA. AT THIS TIME...WE LIMITED THE MENTION DUE TO UNCERTAINTY IN COVERAGE. MUCH OF THE GUIDANCE AT THIS TIME SUGGESTS THE COVERAGE WILL BE LIMITED UNTIL LATE IN THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DLH 31 24 24 -1 / 10 50 10 0 INL 32 16 16 -10 / 30 60 10 0 BRD 34 22 22 5 / 10 40 0 0 HYR 33 27 27 -2 / 10 50 20 0 ASX 34 27 27 2 / 10 50 20 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...GSF LONG TERM...JJM AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
1141 PM CST TUE JAN 27 2015 .UPDATE... ISSUED AT 843 PM CST TUE JAN 27 2015 AN AREA OF FGEN OVER FAR NORTHEAST MINNESOTA HAS LED TO NARROW BANDS OF SNOW...CAPABLE OF PRODUCING A HALF TO THREE QUARTERS OF AN INCH OF SNOW OVER A NARROW AREA. WE INCREASED POPS AND WILL CONTINUE TO MAKE ADJUSTMENTS THROUGH THE LATE EVENING AS THE BANDS MOVE EAST AND NORTH. UPDATE ISSUED AT 643 PM CST TUE JAN 27 2015 WE UPDATED TO INCREASE THE CHANCE FOR SNOW...ESPECIALLY ACROSS FAR NORTHERN MINNESOTA. HIGH RES MODELS SUPPORT A BETTER CHANCE THERE. FURTHER SOUTH...FORECAST SOUNDINGS SHOW DRIER AIR PRESENT IN THE LOW/MID LEVELS WHICH WILL LEAD TO A LESSER CHANCE FOR SNOW OR JUST SOME FLURRIES. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 247 PM CST TUE JAN 27 2015 MAIN CONCERNS IN THE SHORT TERM ARE FOCUSED AROUND THE POTENTIAL FOR LIGHT SNOW ALONG THE BORDERLAND TONIGHT AND WEDNESDAY MORNING...AND THE NEXT SHOT OF A WINTRY MIX WEDNESDAY AND WED NIGHT. A MIX OF SNOW...SLEET AND FREEZING RAIN IS POSSIBLE...AND WINTER WEATHER HEADLINES MAY BE NEEDED. WEAK UPPER LEVEL RIDGE ORIENTED FROM WRN QUEBEC INTO THE UPPER MIDWEST THIS AFTERNOON WITH AN ASSOCIATED SFC RIDGE AXIS FURTHER TO THE E/SE. ON THE WRN EDGE OF THIS RIDGE THERE IS AN AREA OF FAIRLY STRONG WAA OVER THE NRN PLAINS. INDICATIVE OF THIS WARM AIR ARE THE UPPER 60 AND LOWER 70 DEGREE TEMPERATURES IN WRN SOUTH DAKOTA. CONDITIONS ARE NOT AS PLEASANT ACROSS THE NORTHLAND WITH MUCH OF THE REGION ENSHROUDED IN CLOUD COVER AND TEMPERATURES IN THE UPPER 20S AND LOWER 30S. STILL NOT TOO BAD FOR LATE JANUARY. THE DOME OF WARM AIR OVER THE PLAINS TODAY WILL GRADUALLY SHIFT TO THE SOUTHEAST AS THE RIDGE BREAKS DOWN AND THE NEXT UPPER S/W AND SFC LOW MOVE IN FROM THE NW. A WEAK LEAD WAVE...AHEAD OF THE MAIN TROUGH WILL PASS THROUGH WRN ONTARIO AND BRUSH PORTIONS OF THE ARROWHEAD AND BORDERLAND REGION WITH LIGHT SNOW TONIGHT AND WEDNESDAY MORNING. ONLY LIGHT SNOW AMTS ARE EXPECTED. THE BRUNT NEXT WINTER SYSTEM WILL BEGIN TO MOVE INTO N-CENTRAL MN LATE WEDNESDAY MORNING WITH A MIX OF SNOW AND FREEZING RAIN/DRIZZLE...THAT WILL SPREAD TO THE SOUTH THROUGH THE AFTERNOON. AS THE PRECIPITATION MOVES IN...A COLDER AIR MASS WILL AS WELL. BUT NOT BEFORE THE WEDGE OF WARM AIR IN THE MID LEVELS CAN ALTER THE PRECIPITATION TYPE TO A WINTRY MIX...MAINLY ALONG AND SOUTH OF A LINE PARALLEL TO HIGHWAY 2. THE BULK OF THE PRECIP...NAMELY HEAVY SNOW...WITH THIS SYSTEM WILL FALL NORTH OF THE INTERNATIONAL BORDER...CLOSER TO THE UPPER LEVEL FORCING AND ALONG A AREA OF ENHANCED MID LEVEL F-GEN. HOWEVER...NE MN AND NW WI WILL SEE LIGHTER PRECIP...BUT STILL ENOUGH TO CAUSE POTENTIALLY HAZARDOUS TRAVEL/ROAD CONDITIONS DURING THE DAY WED AND WED NIGHT. COULD SEE 1 TO 2 INCHES OF SNOW ACROSS THE ARROWHEAD...AND LIGHT ICE ACCUMULATIONS POSSIBLE FROM WASKISH TO THE TWIN PORTS AND INTO NW WI. ANOTHER ROUND OF WINTER WEATHER ADVISORIES COULD BE NEEDED. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 247 PM CST TUE JAN 27 2015 A STRONG COLD FRONT WILL MOVE THROUGH THE NORTHLAND EARLY THURSDAY IN THE WAKE OF A PASSING CLIPPER SYSTEM. THERE WILL BE STRONG COLD AIR ADVECTION DURING THE DAY. PARTLY TO MOSTLY CLOUDY SKIES SHOULD ENSURE THAT THE CAA RESULTS IN FALLING TEMPERATURES THROUGH THE DAY...SO HIGHS WILL BE IN THE MORNING. THE NAM12 AND GFS MODEL SOUNDINGS ARE SHOWING A MIXING LAYER PACKING QUITE A BIT OF NORTHERLY WIND. NOT SURE IF THE LAPSE RATES WILL BE SUFFICIENT ENOUGH TO DRAW DOWN THE 35 TO 40 KNOTS OF WIND THOSE SOUNDINGS ARE SHOWING IN THE MIXING LAYER...BUT SUBSTANTIALLY INCREASING THE SUSTAINED WIND AND WIND GUST FORECAST OVER THE PREVIOUS FORECAST SEEMED WARRANTED. THERE WILL LIKELY BE AT LEAST WIDESPREAD NNW WINDS OF 10 TO 20 MPH WITH GUSTS UP TO 30 MPH. THERE COULD BE SNOW FLURRIES AND LIGHT ACCUMULATING SNOW...PRIMARILY IN NW WISCONSIN DUE TO LAKE ENHANCEMENT. OVERALL...THURSDAY LOOKS LIKE A BLUSTERY DAY WHICH WILL PUT AN END TO OUR RECENT RELATIVELY WARM WEATHER. HIGH PRESSURE WILL MOVE INTO THE NORTHLAND THURSDAY NIGHT. THE LIGHT WINDS WILL PROMOTE RADIATIONAL COOLING...BUT LINGERING CLOUD COVER COULD PROMOTE THE OPPOSITE. IT APPEARS THERE WILL BE NW TO WNW WINDS OF 10 TO 15 KNOTS ALOFT THROUGH THE NIGHT...DESPITE THE SURFACE WINDS BECOMING VERY LIGHT. THE NW WINDS ALOFT COULD MAINTAIN THE CLOUD COVER. NONETHELESS...LOWERED THE THURSDAY NIGHT LOW TEMPERATURES BASED ON A WIDE BLEND. LOWS WILL LIKELY BE NEAR OR UP TO SEVERAL DEGREES BELOW ZERO. SOUTHWEST FLOW WILL DEVELOP FRIDAY IN THE WAKE OF THE PASSING HIGH PRESSURE AND IN ADVANCE OF AN APPROACHING CLIPPER IN SASKATCHEWAN AND MANITOBA. THE INFLUX OF WARMER AIR SHOULD ALLOW TEMPERATURES TO RECOVER 15 TO 20 DEGREES BY FRIDAY AFTERNOON. HIGHS WILL BE ABOUT 5 DEGREES BELOW NORMAL. ANOTHER WEAK CLIPPER SYSTEM WILL MOVE THROUGH THE NORTHLAND FRIDAY NIGHT AND EARLY SATURDAY. THIS COULD BRING ANOTHER DUSTING OF SNOW TO THE FORECAST AREA. THE NORTHERN FA APPEARS TO HAVE THE BEST CHANCE OF SEEING THIS DUSTING. A PROLONGED PERIOD OF COLD N TO NW FLOW WILL DEVELOP SATURDAY IN THE WAKE OF THE CLIPPER AND ITS COLD FRONT...AND CONTINUE THROUGH MONDAY. THIS WILL LEAD TO ANOTHER COOLING TREND. TEMPERATURES WILL LIKELY BE 15 TO 20 DEGREES BELOW NORMAL DURING THIS TIME. WIND CHILL TEMPERATURES MIGHT FLIRT WITH READINGS OF -20 DEGREES OR COLDER AT NIGHT...BOTH SUNDAY NIGHT AND MONDAY NIGHT. THE SNOWBELT REGION OF NW WISCONSIN WILL LIKELY GET LIGHT LAKE EFFECT SNOW SUNDAY INTO MONDAY DUE TO THE COLD NW FLOW OVER WESTERN LAKE SUPERIOR. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1140 PM CST TUE JAN 27 2015 MVFR CEILINGS WERE ADVANCING NORTH THROUGH KFOZ HEADING TOWARD KINL. AN AREA OF VFR CONDITIONS ALSO EXTENDED FROM KINL THROUGH KTWM INTO KHYR. THE RAP SHOWS VFR CEILINGS WILL PREVAIL OVER EASTERN PORTIONS OF THE NORTHLAND FOR A TIME TONIGHT...BUT SHOULD LOWER ON WEDNESDAY AS LOW LEVEL WAA STRENGTHENS AGAIN. THE FGEN BAND OF SNOW OVER FAR NORTHEAST MINNESOTA HAS DIMINISHED THIS EVENING AND WE EXPECT SOME SPOTTY SNOW OVERNIGHT. AN AREA OF LOW PRESSURE WILL MOVE INTO THE AREA ON WEDNESDAY AND WILL BRING A THREAT FOR SOME MIXED PRECIPITATION TO THE AREA. AT THIS TIME...WE LIMITED THE MENTION DUE TO UNCERTAINTY IN COVERAGE. MUCH OF THE GUIDANCE AT THIS TIME SUGGESTS THE COVERAGE WILL BE LIMITED UNTIL LATE IN THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DLH 25 33 23 24 / 30 30 50 10 INL 27 32 14 16 / 60 30 60 10 BRD 27 34 21 22 / 10 20 40 0 HYR 24 34 27 27 / 10 10 50 20 ASX 25 36 27 28 / 30 10 50 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...MELDE SHORT TERM...BJT LONG TERM...GROCHOCINSKI AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS HASTINGS NE
352 AM CST WED JAN 28 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 344 AM CST WED JAN 28 2015 BEEN ANOTHER QUIET NIGHT ACROSS THE AREA...THANKS TO AN UPPER LEVEL SHORTWAVE RIDGE AXIS THAT HAS BEEN STEADILY MAKING ITS WAY EAST THROUGH THE PLAINS...PUSHED BY AN UPPER LEVEL DISTURBANCE MOVING INTO WRN PORTIONS OF WY. AT THE SURFACE...THE PATTERN OVER THE CWA IS ONCE AGAIN ON THE WEAKER SIDE...WITH A TROUGH AXIS SET UP OVER THE HIGH PLAINS...RESULTING IN LIGHT AND AT TIMES VARIABLE WINDS. TEMPS EARLY THIS MORNING AT 3 AM RANGE ANYWHERE FROM THE MID 20S IN THE NORTH TO MID 40S IN THE FAR SWRN CORNER OF THE CWA. THE MAIN STORY THROUGH THE SHORT TERM PERIOD LIES WITH THAT UPPER LEVEL DISTURBANCE PUSHING INTO WY THIS MORNING...AND THE ACCOMPANYING FRONTAL BOUNDARY IT WILL PUSH THROUGH THE CWA. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE TIMING OF THIS DISTURBANCE...SHOWING IT MOVING INTO THE NEB PANHANDLE NEAR MIDDAY TODAY...BY 00Z THIS EVENING THE TROUGH AXIS LOOKS TO BE EXTENDING THROUGH THE HEART OF THE CWA...BEFORE PUSHING OFF TO THE MISSOURI RIVER AREA BY MIDNIGHT TONIGHT. A WEAKER SECOND MID LEVEL DISTURBANCE QUICK ON THE HEELS OF THE MAIN ONE IS FORECAST TO BE WORKING INTO THE AREA AS WE GET INTO THE EARLY MORNING HOURS THURSDAY. EVEN WITH THERE ACTUALLY BEING A SYSTEM TO TALK ABOUT...MODELS /INCLUDING THE MORE SHORT TERM HIRES LIKE THE WRF/ OVERALL CONTINUE TO BE IN GOOD AGREEMENT SHOWING CONDITIONS REMAINING DRY...JUST NOT A LOT OF MOISTURE TO WORK WITH. THAT BEING SAID...SOME MODELS ARE HINTING AT THE POTENTIAL OF SOME VERY LIGHT PRECIP FALLING THIS EVENING/OVERNIGHT...BUT KEEP THAT SIGNAL JUST OUTSIDE THE N/NERN BORDERS OF THE CWA. WILL BE SOMETHING FOR THE DAY SHIFT TO MONITOR WITH THE 12Z RUN OF MODELS THIS MORNING. AT THE SFC...WINDS WILL REMAIN ON THE LIGHTER SIDE THIS MORNING...BEFORE THE WIND SHIFT OF THE COLD FRONT ACCOMPANYING THIS SYSTEM PASSES THROUGH THE CWA...WHICH MODELS SHOW PUSHING ABOUT HALFWAY THROUGH THE CWA BY MID MORNING AND MAKING IT TO THE ERN FRINGE OF THE CWA AROUND MIDDAY. THIS WILL USHER IN A PUSH OF GUSTY W/NWRLY WINDS /15 TO 25 MPH IS FORECAST/...BUT THE MAIN PUSH OF COLDER AIR IS LAGGING BEHIND. TEMPS ALOFT COOL A TOUCH DURING THE DAY...BUT HIGHS ARE STILL FORECAST TO BE WELL ABOVE AVERAGE...THANKS TO THE MILD AIR/DOWNSLOPING WINDS. NOT EXPECTED TO BE AS WARM AS TUESDAY...BUT TRENDED HIGHS TOWARD THE MAV AND RAP /WHICH DID PRETTY WELL TUESDAY/...WHICH PUTS THE MAJORITY OF THE CWA AT LEAST INTO THE MID 60S /THE EXCEPTION AGAIN IS THE E/NERN PORTIONS/...WITH HIGHS NEAR 70 FORECAST IN NC KS. IF TEMPS PAN OUT AS FORECAST...IT WOULD SET A NEW RECORD HIGH TEMPS IN GRAND ISLAND. BUT CONFIDENCE ISNT THE HIGHEST...AS THERE ARE MODELS THAT SAY IT WILL FALL SHORT OF/MAYBE TIE THE RECORD OF 63 DEGREES. THE RECORD AT HASTINGS IS 69 DEGREES...AND THE RAP IS BASICALLY THE ONLY ONE SHOWING THE POTENTIAL FOR TEMPS TO MAKE A RUN AT THAT RECORD. FIRE WX CONCERNS ARISE AGAIN...SEE FIRE WEATHER SECTION BELOW FOR ADDITIONAL INFORMATION. THIS EVENING/TONIGHT...ONE MIGHT THINK THAT WINDS WE HAVE THIS AFTERNOON WOULD TAPER OFF...BUT WITH THE MAIN PUSH OF COLD AIR ADVECTION...BETTER PRESSURE RISES/TIGHTER PRESSURE GRADIENT...AND STRONGER WINDS ALOFT TO TAP INTO...THATS NOT THE CASE. MADE SOME ADJUSTMENTS TO WIND SPEEDS...WHICH WILL BE ON A SECOND INCREASE THIS EVENING...AND BY MIDNIGHT TONIGHT SPEEDS IN THE 25 TO 30 MPH RANGE WILL BE POSSIBLE...MAINLY ACROSS OUR SC NEB COUNTIES. LOOKS TO REMAIN BREEZY INTO THE EARLY MORNING HOURS THURSDAY. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 344 AM CST WED JAN 28 2015 GUIDANCE SUGGESTS AN UPPER TROPOSPHERIC SHORT WAVE WILL BE NOTED OVER THE MID-MISSISSIPPI VALLEY TO START THE LONG-TERM FORECAST PERIOD AT 12Z THURSDAY...THUS HELPING PROVIDE NORTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA. THIS NORTHWESTERLY FLOW IS EXPECTED TO PERSIST OVER OUR AREA THURSDAY INTO THURSDAY NIGHT BEFORE THE APPROACH OF AN UPPER TROPOSPHERIC LONGWAVE TROUGH AXIS PROMOTES QUASI-ZONAL TO SOUTHWESTERLY UPPER TROPOSPHERIC FLOW FRIDAY THROUGH SATURDAY. THIS UPPER TROPOSPHERIC TROUGH AXIS IS EXPECTED TO CLEAR OUR AREA SATURDAY NIGHT...THUS ALLOWING FOR NORTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA AS WE HEAD INTO THE EARLY PART OF NEXT WEEK. GUIDANCE SUGGESTS AN OVERALL LACK IN OMEGA WILL KEEP US DRY THURSDAY...THURSDAY NIGHT AND THROUGH THE DAY FRIDAY...AND SUCH HAS BEEN PRESENTED IN THE OFFICIAL FORECAST. STARTING FRIDAY NIGHT AND CONTINUING INTO SATURDAY...SATURDAY NIGHT AND PERHAPS EARLY SUNDAY...UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH AXIS IS EXPECTED TO PROMOTE ENOUGH OMEGA FOR PRECIPITATION PRODUCTION ACROSS MUCH OF THE REGION...INCLUDING OUR CWA. THE OPERATIONAL GFS AND EC CONTINUE TO COME INTO BETTER AGREEMENT BY SUGGESTING PRECIPITATION WILL MOVE IN FROM SOUTHWEST TO NORTHEAST ACROSS MUCH OF OUR AREA...AGAIN BEGINNING FRIDAY NIGHT...WITH WIDESPREAD PRECIPITATION THEN CONTINUING ACROSS THE AREA SATURDAY AND SATURDAY NIGHT BEFORE MOVING EAST...ALONG THE UPPER TROPOSPHERIC TROUGH AXIS...AROUND OR SHORTLY AFTER SUNRISE SUNDAY. INTERESTING TO NOTE THAT THE NAM...WHICH THROUGH 84 HOURS IS JUST NOW UP TO 12Z SATURDAY...APPEARS TO KEEP THE PRIMARY AXIS OF OMEGA WELL TO OUR SOUTHEAST AND AS A RESULT...KEEPS US DRY THROUGH 12Z SATURDAY. ALTHOUGH IT WILL BE VERY INTERESTING TO SEE HOW THE NAM UNFOLDS THROUGH THE NEXT FEW RUNS...GIVEN THE AFOREMENTIONED DATA FROM THE OPERATIONAL GFS AND EC...IT SEEMS PRUDENT TO PRESENT YET ANOTHER INCREASE IN POPS FOR THIS WEEKEND AND 30-60% POPS ARE NOW SHOWN IN THE OFFICIAL FORECAST...WITH THE HIGHEST POPS RELEGATED TO OUR SOUTHEAST WHICH IS WHERE GUIDANCE SUGGESTS THE STRONGEST OMEGA AND MOST EFFICIENT PRECIPITATION PRODUCTION WILL RESIDE DURING THIS UPCOMING STORM SYSTEM. ONCE PRECIPITATION COMES TO AN END ON SUNDAY...GUIDANCE SUGGESTS DRY CONDITIONS SHOULD BE OBSERVED SUNDAY NIGHT THROUGH TUESDAY...AND SUCH HAS BEEN PRESENTED IN THE OFFICIAL FORECAST. ALTHOUGH IT APPEARS PRECIPITATION COULD START OUT AS RAIN FRIDAY NIGHT...FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE OPERATIONAL GFS AND EC...SUGGEST THE LOWER TROPOSPHERE WILL BE SUPPORTIVE FOR SNOWFALL AT THE SURFACE BY 12Z SATURDAY AND CONTINUING INTO SUNDAY. THAT SAID...WITH A CONTINUED SOUTH/SOUTHEASTERLY BOUNDARY- LAYER WIND FIELD EXPECTED THROUGH THE DAY SATURDAY...THERE IS STILL AT LEAST AN OPPORTUNITY FOR SOME TEMPERATURE RECOVERY NEAR THE SURFACE DURING THE DAY SATURDAY AND SUPERBLEND RESPONDED BY PROVIDING SATURDAY HIGHS IN THE UPPER 30S AND LOW 40S. THERE ARE SUGGESTIONS FROM MULTIPLE SETS OF GUIDANCE THAT THIS TEMPERATURE FORECAST FOR SATURDAY IS TOO HIGH AND NEEDS TO BE REDUCED BY 4-5 DEGREES. WENT AHEAD WITH A ~2 DEGREE DECREASE FROM THE SUPERBLEND SOLUTION FOR SATURDAY HIGHS TO ACCOUNT OF THIS...BUT EVEN NOW THE OFFICIAL FORECAST CALLS FOR SATURDAY TEMPERATURE READINGS IN THE UPPER 30S FOR MOST LOCATIONS AND GIVEN THIS...DESPITE FORECAST PROXIMITY SOUNDINGS FROM THE OPERATIONAL GFS AND EC SUGGESTING SNOWFALL WILL BE THE PRIMARY PRECIPITATION TYPE DURING THE DAY SATURDAY...FIND IT HARD TO JUSTIFY AN ALL-SNOW FORECAST WITH SURFACE TEMPERATURE READINGS SO HIGH. AS A RESULT...OPTED TO GO WITH A RAIN AND SNOW MIX DURING THE DAY SATURDAY...WITH ALL SNOW THEN EXPECTED SATURDAY NIGHT INTO SUNDAY AS DIABATIC HEATING IS LOST AND A BOUNDARY-LAYER BAROCLINIC ZONE CLEARS THE AREA. OBVIOUSLY THE TEMPERATURE FORECAST FOR SATURDAY WILL NEED TO BE CLOSELY MONITORED AS ANY MORE OF A DECREASE IN SATURDAYS TEMPERATURE FORECAST WOULD SUGGEST MORE SNOW THAN RAIN DURING THE DAY SATURDAY...AND MORE IN THE WAY OF SNOW ACCUMULATION. OBVIOUSLY STORM-TOTAL SNOWFALL ACCUMULATION WILL BE HEAVILY DEPENDENT UPON HOW MUCH SNOWFALL IS REALIZED DURING THE DAY SATURDAY...AND GIVEN THE UNCERTAINTY WITH RESPECT TO PRECIPITATION TYPE AND RESULTANT SNOW ACCUMULATION DURING THE DAY SATURDAY...IT STILL REMAINS TOO EARLY TO GET SPECIFIC ON SNOW AMOUNTS IN THE OFFICIAL FORECAST. THAT SAID...ONCE AGAIN TAKING THE OPERATIONAL GFS AND EC AT FACE VALUE SUGGESTS ADVISORY-WORTHY ACCUMULATION OF ~3 INCHES COULD BE REALIZED ACROSS PORTIONS OF THE CWA SATURDAY NIGHT INTO EARLY SUNDAY MORNING ALONE...DESPITE WHAT HAPPENS DURING THE DAY SATURDAY. IN ADDITION...GUIDANCE IS NOW SUGGESTING THAT AN INCREASING PRESSURE GRADIENT POST-FROPA SATURDAY NIGHT INTO SUNDAY WILL PROMOTE A STRONG WIND...SUSTAINED AT AROUND 18KTS WITH HIGHER GUSTS. THIS WIND...WORKING IN CONCERT WITH THE SNOWFALL...WOULD LIKELY CREATE AT LEAST PERIODIC VISIBILITY RESTRICTION IN BLOWING SNOW. SO...GIVEN THE FACT THAT WE NOW HAVE "LIKELY" POPS IN THE FORECAST FOR PORTIONS OF THE AREA THIS WEEKEND...AND THE FACT THAT IT NOW APPEARS WE HAVE AN OPPORTUNITY FOR BLOWING SNOW AND VISIBILITY RESTRICTION...FEEL IT PRUDENT TO INTRODUCE A MENTION OF ACCUMULATING SNOWFALL AND VISIBILITY RESTRICTION DUE TO BLOWING SNOW FOR THIS WEEKEND IN THE HWO. FINALLY...HIGHS TO START THE LONG-TERM FORECAST PERIOD ON THURSDAY AND FRIDAY ARE STILL EXPECTED TO CLIMB INTO THE 40S...BUT WILL FALL INTO THE 20S POST-FROPA STARTING EARLY NEXT WEEK. OVERNIGHT LOWS IN THE 20S AND 30S ARE ALSO EXPECTED TO START THE LONG-TERM FORECAST PERIOD...BUT THESE READINGS WILL LIKELY FALL INTO THE SINGLE DIGITS AND TEENS EARLY NEXT WEEK AS WELL. && .AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1130 PM CST TUE JAN 27 2015 QUIET WEATHER WITH VFR CONDITIONS CURRENTLY FORECAST FOR THIS TAF PERIOD...WITH THE PRIMARY CONCERN LYING WITH WINDS. A WEAKER SURFACE PATTERN CURRENTLY IN PLACE LOOKS TO KEEP SRLY WINDS ON THE LIGHTER SIDE TONIGHT...BEFORE BECOMING MORE WRLY NEAR SUNRISE AS A COLD FRONT APPROACHES FROM THE WEST. THIS FRONT STARTS WORKING ITS WAY THROUGH THE AREA DURING THE MORNING HOURS. EXPECTING THE FRONT AND ACCOMPANYING GUSTIER NW WINDS TO MAKE THEIR WAY THROUGH THE TERMINAL AREAS DURING THE MID MORNING HOURS...WITH SPEEDS THEN INCREASING INTO THE 20 TO 25 MPH RANGE WITH HIGHER GUSTS...WHICH ARE EXPECTED TO CONTINUE THROUGH THE DURATION OF THIS TAF PERIOD. && .FIRE WEATHER... ISSUED AT 344 AM CST WED JAN 28 2015 GUSTY W/NW WINDS ARE EXPECTED TO DEVELOP ACROSS THE CWA DURING THE DAYTIME HOURS TODAY...AND ABOVE AVERAGE TEMPERATURES ARE ONCE AGAIN FORECAST. HIGH TEMPERATURES REACHING WELL INTO THE 60S TO NEAR 70 DEGREES IN SOME LOCATIONS...COMBINED WITH DEWPOINTS FORECAST TO FALL TO NEAR 30 DEGREES WILL RESULT IN NEAR CRITICAL FIRE WEATHER CONDITIONS ACROSS PORTIONS OF THE CWA. THE BEST CHANCE FOR RELATIVE HUMIDITY VALUES TO FALL INTO THE 20 TO 25 MPH RANGE WITH THOSE GUSTY WINDS WILL LIE ACROSS AREAS GENERALLY ALONG AND WEST OF A LEXINGTON NEB TO BELOIT KS LINE. && .CLIMATE... ISSUED AT 331 AM CST TUE JAN 27 2015 YET ANOTHER DAY WITH FORECAST HIGHS WELL ABOVE AVERAGE IS EXPECTED TODAY. AVERAGE HIGHS FOR THIS TIME OF YEAR ARE MAINLY IN THE MID 30S...WITH HIGHS FORECAST TODAY TO REACH INTO THE 60S /NEAR 70 POSSIBLE ACROSS SRN LOCATIONS/. HERE IS THE RECORD HIGH TEMPERATURE INFORMATION FOR TODAY...WITH GRAND ISLAND CURRENTLY FORECAST TO BREAK THAT RECORD...BUT HASTINGS FORECAST TO FALL A BIT SHORT. GRAND ISLAND: RECORD IS 63 DEGREES IN 1986. FORECAST HIGH: 65 HASTINGS: RECORD IS 69 DEGREES IN 1931. FORECAST HIGH: 65 && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ADP LONG TERM...BRYANT AVIATION...ADP FIRE WEATHER...ADP CLIMATE...ADP
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
319 AM CST WED JAN 28 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 316 AM CST WED JAN 28 2015 TRICKY TEMPERATURE FORECAST TODAY...WHICH WILL BE LARGELY DEPENDENT ON THE EXTENT OF CLOUD COVERAGE. VERY MILD 925 MB TEMPERATURES ABOVE ZERO AND SOUTHERLY WINDS AT THE SURFACE WILL TAP INTO SOME CONTINUED SEASONABLY WARM TEMPERATURES. THE QUESTION IS HOW MUCH CLOUD COVER WILL IMPACT WARMING TODAY. THE MOST RECENT HRRR HAS A GOOD HANDLE ON CLOUDS EARLY THIS MORNING...WHICH WILL SHIFT EASTWARD INTO THE MIDDAY HOURS. THINK THE THE NORTHEASTERN HALF OF THE FORECAST AREA...FROM EAST CENTRAL SD INTO SOUTHWEST MN AND THE IOWA GREAT LAKES ARE WILL HOLD ONTO MOSTLY CLOUDY SKIES THE BULK OF THE DAY. KEPT TEMPERATURES ON THE CONSERVATIVE SIDE OF GUIDANCE IN THIS AREA. IF CLOUDS LOOK LESS ABUNDANT...COULD SEE READINGS WARM ABOVE FORECAST HIGHS. ELSEWHERE...MOSTLY SUNNY TO PARTLY CLOUDY SKIES THROUGH MID AFTERNOON WILL GIVE WAY TO CLOUDS WITH THE ANTICIPATED FRONTAL PASSAGE LATE AFTERNOON. SOUTH CENTRAL SD INTO THE MISSOURI VALLEY WILL HAVE THE BEST POTENTIAL TO WARM INTO THE LOW TO MID 50S. WITH THE FRONT TRACKING THROUGH THE AREA MID AFTERNOON INTO THIS EVENING...CLOUDS WILL ROLL BACK INTO THE REGION. NORTHWEST WINDS EXPECTED TO BECOME QUITE WINDY BEHIND THE FRONT WITH 40 TO 50 KT WINDS JUST OFF THE SURFACE. AT THE SURFACE...WINDS WILL LIKELY BE NEAR ADVISORY LEVEL...ESPECIALLY WITH GUSTS AROUND 40 OR 45 MPH. GIVEN THAT THE STRONGEST WINDS ARE EXPECTED IN THE EARLY MORNING HOURS AND ARE MARGINAL FOR AN ADVISORY...WILL HOLD OFF ISSUING ANY HEADLINES FOR NOW. WITH LOW LEVEL STRATUS BLANKETING THE AREA OVERNIGHT...A FAST MOVING SHORTWAVE DROPS ACROSS SOUTHWEST MINNESOTA LATE EVENING INTO THE EARLY MORNING HOURS. NOT MUCH MOISTURE IN PLACE...AND WHILE THE LOW STRATUS DOES THICKEN...THE CLOUD MASS REMAINS LARGELY OUTSIDE THE SNOW GROWTH ZONE. COULD SEE A FEW SNOW ISOLATED SHOWERS DEVELOP MAINLY IN OUR MN COUNTIES...WITH SOME PATCH DRIZZLE ALSO POSSIBLE. SURFACE TEMPERATURES WILL BE NEAR OR JUST ABOVE FREEZING IN THIS AREA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 316 AM CST WED JAN 28 2015 THE SHORTWAVE EXITS THE AREA ON THURSDAY WITH SURFACE HIGH PRESSURE BUILDING INTO THE REGION. IT WILL BE BREEZY WITH A TIGHT GRADIENT ACROSS THE AREA AND GOOD MIXING IN A COLD AIR ADVECTION REGIME. IN RESPONSE TO THE COLDER AIR FILTERING INTO THE REGION BEHIND THE EXITING SHORTWAVE...HIGH TEMPERATURES WILL BE A GOOD 10 TO 15 DEGREES COOLER THAN TODAY...TOPPING OUT IN THE UPPER 20S FROM EAST CENTRAL SD THROUGH SOUTHWESTERN MN...TO UPPER 30S THROUGH THE MO RIVER CORRIDOR. WINDS WILL DIE OFF ON THURSDAY NIGHT...LEADING TO A COLD NIGHT WITH LOWS IN THE LOWER/MID TEENS THROUGH THE EASTERN TWO THIRDS OF THE CWA. TO THE WEST...IT WILL NOT BE QUITE AS COLD WITH AN ENSUING SOUTHEASTERLY FLOW BEHIND THE EXITING HIGH PRESSURE...WITH LOWS GENERALLY LOWER 20S. FRIDAY WILL SEE WARMING WITH A STRENGTHENING SOUTHERLY FLOW ON THE BACKSIDE OF THE HIGH. HIGH TEMPERATURES WILL RUN LOWER 30S NORTHEAST TO AS WARM AS THE MID 40S THROUGH SOUTH CENTRAL SD. ON SATURDAY NORTHERN STREAM UPPER LEVEL ENERGY DROPS OUT OF WESTERN CANADA AND SLIDES SOUTHWARD AS SOUTHERN STREAM ENERGY LIFTS TO THE NORTH...CONVERGING OVER THE CENTRAL PLAINS. STILL SOME MODEL DIFFERENCES ON HOW THIS SCENARIO EVOLVES...BUT DOES POTENTIALLY BRING PRECIPITATION TO AT LEAST OUR SOUTHERN AND EASTERN CWA FOR LATER ON SATURDAY AFTERNOON AND SATURDAY NIGHT. PRECIPITATION TYPE LOOKS TO BE MAINLY IN THE FORM OF SNOW...WITH COOLING THERMAL PROFILES AS LOW PRESSURE OVER THE JAMES BAY BEGINS TO DRIVE COLDER AIR SOUTHWARD. AT THIS POINT SNOWFALL AMOUNTS LOOK TO BE IN THE RANGE OF 2 TO 3 INCHES IN OUR SOUTHEAST...THOUGH WILL HAVE TO WATCH THE TRACK OF THIS SYSTEM FOR GREATER SNOWFALL AMOUNTS IF IT TRENDS FARTHER TO THE NORTH. IT STILL WONT BE UNREASONABLY COLD ON SATURDAY WITH HIGHS MAINLY IN THE 30S...BUT BY SATURDAY NIGHT AND SUNDAY MUCH COLDER AIR WILL HAVE SETTLED INTO THE REGION WITH HIGHS ON SUNDAY MOSTLY IN THE TEENS. THE COLD AIR THEN LOOKS TO LINGER THROUGH NEXT MONDAY...WITH SOME MODERATION POSSIBLE BY TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1041 PM CST TUE JAN 27 2015 MVFR CEILINGS JUST BRUSHING EASTERN EDGE OF THE FORECAST AREA AT THE START OF THE TAF PERIOD...AND MAIN QUESTION IS WHETHER THOSE MVFR CONDITIONS WILL EXPAND BACK INTO THE FORECAST AREA LATER TONIGHT AND INTO WEDNESDAY MORNING. GIVEN STRONGER BOUNDARY LAYER WIND PROFILE WHICH SHIFTS FROM SOUTHEAST AT THE SURFACE...TO SOUTH-SOUTHWEST IN THE POTENTIAL STRATUS LAYER AND ABOVE...PREFER MODEL SOLUTIONS WHICH KEEP THE AREA LARGELY VFR. AREA TO WATCH MAY BE KHON...AS SATELLITE SHOWING EITHER STRATUS OR FOG HUGGING THE HIGHER ELEVATIONS WEST OF THE JAMES RIVER VALLEY. HOWEVER PREFERRED MODELS WHICH KEEP THIS JUST WEST OF KHON...AND THUS WILL CARRY VFR CONDITIONS AT ALL TAF SITES THROUGH SUNSET WEDNESDAY. COLD FRONT WILL PUSH ACROSS THE FORECAST AREA IN THE LATE MORNING AND AFTERNOON. MVFR CEILINGS AND INCREASING NORTHWEST WINDS WILL TRAIL SURFACE FRONTAL PASSAGE BY 3-6 HOURS...AS COLDER AIR MOVES IN ALOFT AFTER 29/00Z. FREQUENT GUSTS OF 25-30+ KTS LIKELY WEDNESDAY EVENING. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM... LONG TERM...JM AVIATION...JH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1036 PM CST TUE JAN 27 2015 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND WEDNESDAY ISSUED AT 258 PM CST TUE JAN 27 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH PRESSURE NOSING SOUTHWEST ACROSS THE UPPER PENINSULA AND THE STATE OF WISCONSIN. BUT DESPITE THE RIDGE AXIS SHARPENING OVER NE WISCONSIN...LOW STRATUS HAS BEEN AWFULLY DIFFICULT TO ERODE THIS AFTERNOON. CLOUDS OVER NORTHERN LAKE MICHIGAN ARE VERY SLOWLY ERODING FROM EAST TO WEST...AND AS BOUNDARY LAYER FLOW LIGHTENS AND BACKS TO THE NORTH LATER THIS AFTERNOON...THINK THIS WILL ACCELERATE CLEARING OVER THE FOX VALLEY AND LAKESHORE. OTHERWISE...OVERCAST CONDITIONS TO REMAIN OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. LOOKING UPSTREAM...CLOUDS ARE INCREASING AGAIN OVER THE NORTHERN PLAINS AND NORTHWEST LAKE SUPERIOR AHEAD OF THE NEXT CLIPPER SYSTEM WHICH WILL ARRIVE WEDNESDAY NIGHT. IN THE MEANTIME...CLOUD AND TEMP TRENDS ARE THE MAIN FORECAST CONCERNS. TONIGHT...ARCTIC HIGH PRESSURE WILL TEMPORARILY BUILD ACROSS EASTERN WISCONSIN THIS EVENING THEN RETREAT BACK EAST OVERNIGHT. STILL ANTICIPATING AT LEAST PARTIAL CLEARING TAKING PLACE OVER THE FOX VALLEY AND LAKE SHORE AS THE RIDGE AXIS MOVES INTO THAT AREA. FARTHER WEST...WINDS WILL TURN TO THE SOUTH OR SOUTHWEST...AND TRENDS OVER THE U.P. SUPPORT THAT CLOUDS WILL JUST ROTATE NORTHWARD...LEAVING A LOW OVERCAST DECK IN PLACE. AS A RESULT...INCREASED SKY COVER. THEN OVERNIGHT...MID AND HIGH CLOUDS WILL BE RETURNING FROM THE NORTHWEST...AND ANY CLEARING OVER EASTERN WISCONSIN SHOULD GO BACK TO BROKEN OR OVERCAST. TRENDED WARMER WITH LOW TEMPS DUE TO THE PERSISTENT CLOUD COVER. WEDNESDAY...LOW PRESSURE WILL BE MOVING INTO THE NORTHERN MISSISSIPPI VALLEY DURING THE AFTERNOON. AS WINDS BACK TO THE SOUTHEAST...WARMER LOW LEVEL AIR WILL FINALLY SURGE INTO CENTRAL AND NORTHEAST WISCONSIN...WHICH SHOULD ERODE ANY REMAINING LOW OVERCAST. HOWEVER...WILL STILL HAVE AMPLE MID AND UPPER CLOUDS OVERHEAD...MAKING FOR A MOSTLY CLOUDY DAY. AN 850MB WARM FRONT WILL BE MAKING INTO NORTH-CENTRAL AND CENTRAL WISCONSIN BY LATE IN THE AFTERNOON...BUT PROGGED SOUNDINGS CONTINUE TO SHOW A WEDGE OF DRY AIR AROUND 10KFT THAT SHOULD BE ENOUGH TO KEEP THE AREA DRY. HIGHS WARMING INTO THE LOW TO MID 30S. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY ISSUED AT 258 PM CST TUE JAN 27 2015 NORTHWEST UPPER FLOW WILL CONTINUE THROUGH THE PERIOD...SO IT WILL BE GENERALLY COLD AND DRY. THERE ARE AT LEAST TWO OPPORTUNITIES FOR SOME SNOW. THE FIRST IS TOMORROW NIGHT AND EARLY THURSDAY AS JET ENERGY APPROACHES FROM THE WEST. THERE ISN/T MUCH MOISTURE AVAILABLE UNTIL THE SYSTEM GETS EAST OF WISCONSIN. THEREFORE SNOW SHOULD BE LIGHT AND MIGHT BEGIN AS SLEET ACROSS THE CENTRAL AND EAST CENTRAL AREAS. THERE IS ANOTHER CHANCE OF SNOW SATURDAY NIGHT AND SUNDAY AHEAD OF ARCTIC AIR. THE GFS AND ECMWF HAVE A FEW WAVES OF LOW PRESSURE THAT MOVE NORTHEAST ALONG THE FRONT...RESULTING IN LOTS OF DIFFERENCES IN TIMING AND SNOW AMOUNTS. MILD PACIFIC AIR WILL BRING US WARMER THAN NORMAL TEMPERATURES THURSDAY THEN BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH THE MIDDLE OF NEXT WEEK. THERE. WIND CHILL ADVISORIES MAY BE NEEDED MONDAY. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1035 PM CST TUE JAN 27 2015 LOW CLDS ACTUALLY DISSIPATED IN FAR ERN WI FOR A TIME THIS EVENING. BUT WITH LOW-LEVEL FLOW SHIFTG BACK TO LIGHT SWLY...THEY SHOULD EXPAND BACK ACRS THE AREA. EXPECT CIGS AND VSBYS TO GRADUALLY COME DOWN OVERNIGHT...WITH IMPROVEMENT NOT OCCURRING UNTIL MID-DAY OR AFTN TOMORROW. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......RDM AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
559 AM CST WED JAN 28 2015 .SHORT TERM... 345 AM CST TODAY THROUGH FRIDAY NIGHT... MAIN FORECAST CONCERNS IN THE SHORT TERM ARE CLOUD AND TEMP TRENDS TODAY AND TONIGHT...AND TIMING...COVERAGE AND TYPE OF PRECIPITATION TONIGHT AND THURSDAY AS LOW PRESSURE ORGANIZING OVER THE PLAINS MOVES EAST. RELATIVELY QUIET WEATHER THIS MORNING AS SURFACE HIGH PRESSURE DRIFTS SLOWLY EAST OF THE AREA. SUBSIDENCE ASSOCIATED WITH HEIGHT RISES ALOFT HAS LED TO A STRONG INVERSION AT AROUND 900 HPA HOWEVER PER DVN 00Z SOUNDING...WHICH HAS TRAPPED LOW CLOUDS ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA OVERNIGHT. CLOUDS WERE SLOWLY ERODING FROM THE SOUTHEAST THANKS TO 950-900 HPA WINDS GRADUALLY VEERING TO THE SOUTHEAST AND SOUTH...AND LOWERING SUBSIDENCE INVERSION. RAP GUIDANCE INDICATES SOUTH WINDS WILL INCREASE THIS MORNING AND SHOULD CONTINUE TO LIFT THESE LOWER CLOUDS NORTH TOWARD THE WI BORDER...THOUGH OVERALL NORTH CENTRAL ILLINOIS IS LIKELY TO BE CLOUDIER THAN AREAS SOUTH AND EAST TODAY EVEN AS MID AND HIGH CLOUDS BEGIN TO INCREASE AS WARM ADVECTION DEVELOPS ALOFT. SURFACE LOW PRESSURE IS ALREADY TAKING SHAPE ACROSS THE PLAINS TO OUR WEST THIS MORNING...IN RESPONSE TO A SHORT WAVE TROUGH EMERGING FROM THE CENTRAL/NORTHERN ROCKIES. SURFACE PRESSURE FALLS AHEAD OF THIS DEVELOPING LOW WILL LEAD TO INCREASING SOUTH-SOUTHEAST WINDS NEAR 25 MPH THIS AFTERNOON. DESPITE SOUTHERLY FLOW...LOW LEVEL PARCEL TRAJECTORIES WILL BE LARGELY FROM INDIANA/OHIO WHERE STRONG COOLING HAS OCCURRED NEAR THE SURFACE HIGH THIS MORNING. COMBINED WITH SOME MID/HIGH CLOUD COVER THIS MAY MAKE FOR HIGH TEMPERATURES COMING LATER IN THE DAY WHEN LOW LEVEL WINDS VEER MORE SOUTHERLY AND TAP MILDER AIR CURRENTLY ACROSS THE MISSOURI VALLEY. STRONG SOUTH FLOW WILL CONTINUE TONIGHT AHEAD OF THE APPROACHING SURFACE LOW...ALLOWING TEMPS TO STAY ABOVE FREEZING IN MOST AREAS. GUIDANCE IN GOOD AGREEMENT IN DEVELOPING SOME LIGHT SPOTTY PRECIPITATION ACROSS THE AREA LATE THIS EVENING...EXPANDING OVERNIGHT ESPECIALLY ACROSS NORTHERN/NORTHEASTERN PARTS OF THE FORECAST AREA. FORECAST SOUNDINGS INDICATE WARM LAYER TEMPS ALOFT IN THE +5C RANGE OR BETTER...WITH SATURATION INITIALLY OCCURRING BELOW 700 HPA AND SUPPORTING LIGHT RAIN. WITH BREEZY SOUTH SURFACE WINDS KEEPING TEMPS ABOVE MAINLY ABOVE FREEZING...PRECIPITATION TYPE IS EXPECTED TO REMAIN LIQUID IN MOST LOCATIONS. LOW PROBABILITY DOES EXIST FOR LIGHT FREEZING RAIN ESPECIALLY ACROSS FAR NORTH/NORTHEAST IL...BUT AT THIS TIME FEEL IT IS FAIRLY UNLIKELY. THE SURFACE LOW...AND A PAIR OF UN-PHASED SHORT WAVES....MOVE ACROSS THE CWA DURING THE MORNING AND RESULT IN WINDS SHIFTING TO THE NORTHWEST. THIS BRINGS COLDER AIR INTO THE REGION WITH COLLAPSING THICKNESS FIELDS SUPPORTING LINGERING PRECIPITATION CHANGING OVER FROM LIGHT RAIN TO A BRIEF RAIN/SLEET/SNOW MIX BEFORE ENDING FROM WEST-EAST. MOST PRECIPITATION SHOULD END BY NOON WEST OF ABOUT THE IL/IN STATE LINE...AND SHORTLY AFTER ACROSS NORTHWEST INDIANA. HOWEVER...GUSTY NORTH-NORTHWEST WINDS AND COLDER AIR SPREADING ACROSS LAKE MICHIGAN WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS ACROSS PARTS OF EASTERN LAKE AND PORTER COUNTIES ESPECIALLY THURSDAY EVENING INTO EARLY FRIDAY MORNING. THE REMAINDER OF THE AREA WILL JUST BE BLUSTERY AND COLDER...WITH NORTH-NORTHWEST WINDS GUSTING ABOVE 30 MPH AT TIMES THURSDAY BEFORE SLOWLY DIMINISHING THURSDAY NIGHT. AFTER MORNING HIGHS IN THE MID-UPPER 30S OR EVEN NEAR 40 IN SOME SPOTS...THURSDAY NIGHT LOOKS TO BE COLD WITH LOWS IN THE TEENS TO LOW 20S AND SINGLE DIGIT WIND CHILLS. SURFACE HIGH PRESSURE SPREADS INTO THE AREA AGAIN ON FRIDAY...WITH TEMPERATURES STRUGGLING INTO THE MID-UPPER 20S BUT WITH MUCH LIGHTER WINDS. LAKE SNOW SHOWERS WILL DIMINISH ACROSS NORTHWEST INDIANA AS INVERSION HEIGHTS LOWER AND LOW LEVEL WINDS DIMINISH...WITH SUNSHINE ELSEWHERE. RATZER && .LONG TERM... 345 AM CST SATURDAY THROUGH TUESDAY... THE MAIN FOCUS IN THE EXTENDED PERIOD IS ON A STORM SYSTEM WHICH LOOKS TO LIFT THROUGH THE OHIO VALLEY LATE SATURDAY NIGHT THROUGH SUNDAY. ECMWF/GFS ARE IN RELATIVELY GOOD AGREEMENT IN TAKING SURFACE LOW TRACK ALONG THE OHIO RIVER...THOUGH GFS IS A LITTLE SLOWER AND GEFS ENSEMBLE MEMBERS STILL SHOW QUITE A BIT OF SPREAD IN THEIR SOLUTIONS AT THE SURFACE. GEM ALSO SLOWER AND A BIT FARTHER SOUTH THAN THE OTHER GLOBAL MODELS. DEPENDING UPON HOW THIS SYSTEM EVENTUALLY TRACKS...IT COULD BE A SNOW PRODUCER FOR ALL OR PART OF THE CWA...AS IT TAPS GULF MOISTURE DEFORMATION BAND WOULD LIKELY CROSS CENTRAL IL/IN. GLOBAL MODELS ALSO INDICATE A STRONG SURGE OF ARCTIC AIR IN THE WAKE OF THIS SYSTEM...WITH SIGNIFICANTLY COLDER WEATHER I.E. LOWS +/- SINGLE DIGITS AND HIGHS PERHAPS ONLY IN THE TEENS BY MONDAY/TUESDAY. RATZER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * GUSTY SOUTH-SOUTHEAST SURFACE WINDS DEVELOPING BY EARLY AFTERNOON AND STRENGTHENING INTO EVENING. * SCATTERED LIGHT RAIN SHOWERS LIKELY AND MVFR CIGS DEVELOPING OVERNIGHT...AND THE POSSIBILITY OF A BRIEF MIX WITH SNOW AND IFR VISIBILITY BEFORE ENDING THURSDAY MORNING. * SOUTH-SOUTHWEST WINDS AT 2000 FT OF AT LEAST 50 KT THIS EVENING INTO OVERNIGHT THAT MAY CREATE LOW-LEVEL WIND SHEAR. * NORTHWEST WINDS GUSTING TO AROUND 30 KT DURING THE DAY THURSDAY. //DISCUSSION...UPDATED 12Z... CURRENT BATCH OF MVFR CIGS ACROSS NORTHWEST ILLINOIS EARLY THIS MORNING IS BEING STEERED ON SOUTHERLY WINDS EARLY THIS MORNING...WITH RFD LIKELY TO EXPERIENCE AT LEAST TEMPORARY 2000 FT CIGS OR SO THROUGH MID-MORNING. WITH THE APPROACH OF LOW PRESSURE...SOUTH-SOUTHEAST WINDS WILL INCREASE WITH GUSTS LIKELY IN THE AFTERNOON AND PERSISTING...AND LIKELY STRENGTHENING...INTO THE EVENING AS STRONG PRESSURE FALLS ENVELOP THE REGION. GIVEN THE CURRENT AND FORECAST PLACEMENT OF THE LOW PRESSURE...THE WIND DIRECTION SHOULD BE EAST OF SOUTH MUCH OF TODAY AND EARLY THIS EVENING...BEFORE GRADUALLY VEERING AHEAD OF A FRONT LATE TONIGHT. A CHANNEL OF STRONG SOUTHWEST WINDS ALOFT...AROUND 2000-3000 FT...ARE LIKELY TO BE 50 PLUS KNOTS TONIGHT AND COULD RESULT IN SOME LOW-LEVEL WIND SHEAR...ALTHOUGH SURFACE WINDS WILL REMAIN ALSO INCREASED IN SOMEWHAT MIXED CONDITIONS. THE COLD FRONT WILL PASS IN THE PRE-DAWN HOURS THURSDAY. AHEAD OF THIS FRONT SATURATION SHOULD SLOWLY OCCUR NEAR THE INVERSION LEVEL...WHICH IS EXPECTED TO BE AROUND 2000-3000 FT SO CIGS OF THAT HEIGHT SHOULD GRADUALLY DEVELOP AS TONIGHT PROGRESSES. IN ADDITION...THERE WILL BE POTENTIAL FOR SCATTERED RAIN SHOWERS...WITH ANY RAIN POSSIBLY CHANGING TO A RAIN AND SNOW MIX AFTER SUNRISE THURSDAY. ANY MIX IS NOT LIKELY TO LAST LONG BEFORE ENDING...SO ACCUMULATIONS SHOULD BE ONLY A TRACE. //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH IN WIND DIRECTION AND SPEED TODAY AND THIS EVENING...INCLUDING THE WIND DIRECTION REMAINING SLIGHTLY EAST OF SOUTH. * MEDIUM IN PRECIPITATION OCCURRING AT THE AIRFIELD LATER TONIGHT AND EARLY THURSDAY MORNING. * HIGH IN MVFR CIGS LATE TONIGHT INTO THURSDAY MORNING. LOW IN ANY IFR OCCURRING. //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...MAINLY VFR. NORTH-NORTHWEST WINDS. FRIDAY...VFR. NORTHWEST WINDS. SATURDAY...CHANCE OF SNOW AND IFR DURING THE NIGHT. SOUTHWEST WINDS. SUNDAY...SNOW AND IFR LIKELY. NORTHEAST WINDS. MONDAY...CHANCE OF SNOW WITH MVFR LIKELY. IFR POSSIBLE. NORTHWEST WINDS. TUESDAY...CHANCE OF SNOW DURING THE NIGHT. SOUTHWEST WINDS. MTF && .MARINE... 158 AM CST AN ACTIVE PERIOD WILL UNFOLD OVER LAKE MICHIGAN THROUGH THIS FORECAST THANKS TO THE PROGRESSIVE NATURE IN THE WEATHER PATTERN. HIGH PRESSURE EARLY THIS MORNING WILL EXIT THE PICTURE AND A QUICKLY APPROACHING LOW PRESSURE FROM THE WEST WILL BRING INCREASING SOUTHERLY WINDS LATER TODAY INTO THIS EVENING. DURING THE EVENING THERE IS A PERIOD WHERE OCCASIONAL GALES SHOULD OCCUR ACROSS THE SOUTHERN HALF AS SOME INSTABILITY WILL BE PRESENT WITH GALE FORCE WINDS ONLY 1000-1500 FT OFF THE WATER SURFACE. THE LOW SHOULD BE ELONGATED RIGHT DOWN THE AXIS OF THE LAKE AROUND 6 AM THURSDAY BEFORE IT QUICKLY MOVES EAST. THIS WILL RESULT IN STOUT NORTHWEST WINDS AND COLD ADVECTION ACROSS THE LAKE WITH WHAT LOOKS LIKE DEFINITE GALES FOR AT LEAST THE OPEN WATER...INCLUDING 40 KTS WITH 45 KTS EVEN POSSIBLE ESPECIALLY IN THE NORTH. THIS LIKELY WILL BRING SOME FREEZING SPRAY THURSDAY NIGHT TO THE OPEN WATER. AT THIS TIME FORECAST INGREDIENTS ARE A LITTLE SHY FOR HEAVY FREEZING SPRAY SO NO WATCH FOR THAT ISSUED BUT WILL NEED TO BE MONITORED. HAVE OPTED TO GO WITH A GALE WATCH FOR BEHIND THE LOW PRESSURE AS THAT TIME PERIOD WILL BE THE HIGHEST WINDS WITH THE SYSTEM. WILL JUST MENTION OCCASIONAL GALES ON THE FRONT SIDE DURING THIS EVENING ACROSS MAINLY THE SOUTH HALF. SMALL CRAFT ADVISORY CONDITIONS WILL OBVIOUSLY EXIST A GOOD AMOUNT OF THIS TIME ON THE ILLINOIS AND INDIANA NEAR SHORES. WITH A SHORT 4-6 HOUR RESPITE CENTERED ON DAYBREAK THURSDAY AS THE LOW PASSES...HAVE OPTED TO NOT EXTEND THE CURRENT SMALL CRAFT ADVISORY...BUT ONE WILL DEFINITELY BE NEEDED FOR THURSDAY AFTERNOON AND NIGHT...AND FOR THE INDIANA SHORE INTO FRIDAY. THE GALE WATCH DOES INCLUDE PARTS OF THE INDIANA NEARSHORE THAT WILL FEEL THE GREATER FETCH OF ONSHORE WINDS AND THUS COULD REALIZE GALES THURSDAY AFTERNOON AND EVENING. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...NOON WEDNESDAY TO 4 AM THURSDAY. GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON THURSDAY TO 3 AM FRIDAY. && $$ 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
AREA FORECAST DISCUSSION
NWS DES MOINES IA
533 AM CST WED JAN 28 2015 .SHORT TERM /TODAY/... ISSUED AT 355 AM CST WED JAN 28 2015 COMPLICATED FORECAST TODAY TO SAY THE LEAST. INTENSE LOW EAST OF MAINE CONTINUES TO BE HOLDING BACK EASTWARD TRANSLATION OF THE UPPER LEVEL RIDGE OVER THE MIDWEST TODAY...RESULTING IN LOW STRATUS CLOUDS HOLDING ON OVER EASTERN IOWA YESTERDAY AFTERNOON. FAST FORWARD TO CURRENT WITH LOW STRATUS AND LIGHT FOG EXPANDING WEST A BIT INTO CENTRAL IOWA ALONG A WEAK FRONTAL BOUNDARY EXTENDING WEST TO EAST OVER THE FORECAST AREA AT 08Z. MESOSCALE MODELS DOING A BETTER JOB WITH CLOUDS THAN SYNOPTIC...HRRR CAPTURES THE EXPANSION AND GENERALLY BEGINS TO MOVE THE DECK NORTHEAST DURING THE DAY AS THE PLAINS LOW ENTERS IOWA THIS AFTERNOON. OVER THE NORTH...MOISTURE WILL REMAIN FOR MUCH OF THE DAY SO CLOUDS AND MUCH COOLER TEMPERATURES THIS AFTERNOON ARE LIKELY ACROSS THE NORTH. A WIDE RANGE OF TEMPERATURES IS EXPECTED TODAY WITH HIGHS IN THE UPPER 30S FROM MASON CITY TO WATERLOO TO THE MID 50S AT DES MOINES TO NEAR 60 OVER THE FAR SOUTH. WILL CONTINUE THE NEAR RECORD HIGH HEADLINE OVER THE SOUTHWEST AS ONCE THE CLOUDS BACK OFF...TEMPERATURES SHOULD MOVE UP RATHER QUICKLY LATER THIS MORNING AND EARLY AFTERNOON. BY MID TO LATE AFTERNOON CLOUDS WILL BEGIN TO FILL IN AGAIN AS THE LOW BEGINS TO INCREASE LIFT ACROSS THE REGION. BY LATE AFTERNOON PARTLY SUNNY CONDITIONS TO CLOUDY SKIES WILL PREVAIL. WINDS WILL BE SOUTH SOUTHEAST THIS AFTERNOON WITH THE STRONGER WINDS OVER SOUTHEAST SECTIONS. DESPITE THE UNSEASONABLY WARM TEMPERATURES ALOFT...6C NORTHEAST TO 14C SOUTHWEST BY MIDDAY COOLING TO 4C NORTHEAST TO 10C SOUTH...AFTERNOON HIGHS WILL BE ADVECTION BASED RATHER THAN PURE MIXING BASED. TOWARD SUNSET MOSTLY CLOUDY CONDITIONS ARE EXPECTED. .LONG TERM /TONIGHT THROUGH TUESDAY/... ISSUED AT 355 AM CST WED JAN 28 2015 A VERY FAST MOVING SHORTWAVE IS STILL ON TRACK TO IMPACT DMX CWA THURSDAY MORNING. AT 06Z WED...WATER VAPOR IMAGERY EASILY PICKING UP THIS MID TO UPPER LOW CROSSING OVER THE ROCKIES. THE MODELS CONTINUE TO INITIALIZE WELL WITH PLACEMENT OF THIS MID TO UPPER WAVE. TIMING HAS REMAINED CONSISTENT...WITH THE MODELS PLACING THIS LOW DIRECTLY OVER CENTRAL IOWA AT 06Z THU. SOUNDINGS ONCE AGAIN SHOW A SIZABLE DRY AIR POCKET FROM AROUND 850MB TO 600MB WHICH WILL PREVENT CLOUD THICKNESS FROM EXCEEDING 5 KFT AND...SUBSEQUENTLY...KEEP THIS SYSTEM FROM PRODUCING ANYTHING BEYOND LIGHT PRECIP. KMCW TO KEST GFS SOUNDINGS SUPPORT MAINLY DZ/-RA...WITH A VERY NARROW WINDOW OF -IP TO -SN POSSIBLE FROM AROUND 09Z TO 12Z. BY 12Z THU...THIS LOW WILL BE OVER NORTHERN ILLINOIS AND STRONG CAA ALONG WITH VERY DRY AIR IN THE MID TO UPPER LEVELS WILL BE BROUGHT INTO OUR CWA. THOUGH A FAIR AMOUNT OF SUNSHINE IS EXPECTED...DAYTIME TEMPS TO ONLY WARM AROUND 3 TO 5 DEGREES FROM OVERNIGHT MINS DUE TO CAA. THURSDAY`S WINDS REMAIN WORTH MENTIONING. MODELS SHOWING 25 KT TO 30 KT WINDS RIGHT OFF THE DECK...APPROACHING 45 KT TO THE TOP OF THE MIXED LAYER. SFC PRESSURE GRADIENT OF 3MB/100KM TO SUPPORT STRONG WINDS AT THE SFC. WITH LOW OVER GREAT LAKES...WINDS WILL BE STRONGEST ACROSS OUR NORTHERN CWA. IN ALL...WIND ADVISORY BEGINNING EARLY THU AM LOOKING MORE AND MORE LIKELY WITH THE NEXT UPDATE PACKAGE. WHILE FRIDAY SHOULD BE SUNNY AND QUIET...IT LOOKS LIKE QUITE A DIFFERENT STORY IS SHAPING UP FOR THE WEEKEND...ESPECIALLY SATURDAY NIGHT INTO SUNDAY MORNING. THE EURO AND THE GFS ARE BEGINNING TO COME IN LINE BOTH TEMPORALLY AND SPATIALLY WITH BRINGING OUR NEXT CHANCE FOR "IMPACTFUL" SNOW ACCUMULATION TO OUR CWA. FORECAST SOUNDINGS BEGIN TO SATURATE FROM TOP-DOWN SATURDAY AFTERNOON. SEE LITTLE TO NO JUSTIFIABLE REASON FOR PRECIP DURING THE MORNING SATURDAY...SO HAVE LOWERED POPS ACCORDINGLY. SATURDAY EVENING...SOUNDINGS BEGIN TO COMPLETELY SATURATE ACROSS THE CWA FROM SW TO NE...BECOMING COMPLETELY SATURATED BETWEEN 00Z SUN AND 06Z SUN. BOTH GFS AND EURO HAVE A LLJ TRANSPORTING MOISTURE INTO THIS SYSTEM FROM THE GULF OF MEXICO. THE EURO IS SLIGHTLY FURTHER NORTH WITH THIS MOISTURE...WHICH IS HELPING YIELD A COMPARATIVELY HIGHER QPF. HIGHEST SNOWFALL AMOUNTS WILL THUS BE IN OUR SOUTHERN CWA. CROSS SECTIONS CLEARLY SHOW LIFT THROUGH THE DENDRITIC GROWTH ZONE. WAY TOO EARLY FOR ANY HEADLINES AT THIS POINT...BUT WORTH NOTING THAT MODELS MAY BE KEYING IN ON A SOLUTION...WHICH WOULD INCREASE CONFIDENCE. BEHIND THIS SYSTEM...MONDAY INTO THE MID-WEEK...IT IS A LOCK THAT TEMPERATURES WILL BE SIGNIFICANTLY COOLER THAN THEY HAVE BEEN FOR THE PAST TWO WEEKS. THE FORECAST CHALLENGE FOR NOW IS HOW FAR THE BOTTOM WILL FALL OUT ON TEMPS. ENSEMBLE RUNS ARE SHOWING AROUND -1 TO -2 STD DEV ON 850MB TEMPS ACROSS OUR CWA. TONIGHT`S 00Z GFS WAS MARKEDLY COLDER THAN PVS RUNS. THE GFS HAS 850MB TEMPS DOWN TO -19C ACROSS THE NE PORTION OF OUR CWA...WHEREAS THE EURO HAS 850 MB TEMPS DOWN TO ONLY -10C. SINCE OBVIOUS LACK OF CONSISTENCY FROM GFS...WILL LEAN TOWARDS MORE CONSISTENT...LESS EXTREME...EURO. IF THIS 00Z WED GFS SOLN HOLDS IN SUBSEQUENT RUNS...MAX AND MIN TEMPS WILL NEED AT LEAST 5 DEGREES LOPPED OFF. && .AVIATION...28/12Z ISSUED AT 533 AM CST WED JAN 28 2015 STRATUS DECK THE MAIN CHALLENGE EARLY TODAY WITH AREA OF LIFR AND FOG DEVELOPING AHEAD OF BOUNDARY NOW OVER CENTRAL IOWA. LOW PRESSURE IN CENTRAL SOUTH DAKOTA TO MOVE SOUTHEAST. HRRR MODEL AND TRENDS SUGGEST THAT CIGS WILL IMPROVE OVER CENTRAL/SOUTH AFT 15Z WHILE NORTHEAST/NORTH WILL REMAIN IN MVFR/IFR CONDITIONS FOR MOST OF THE DAY. BR AND NOW FG HAS DEVELOPED OVER THE NORTH WITH KMCW DOWN TO 3/4SM. HAVE BROUGHT IN 1/2SM FZFG FOR BRIEF PERIOD PRIOR TO 14Z WITH LIMITED IMPROVEMENT TOWARD 18Z. AFTER THE PASSAGE OF THE LOW TONIGHT...WINDS BECOME MORE NORTHWEST AND INCREASE DRAMATICALLY AFT 06-08Z REMAINING STRONG THROUGH END OF PERIOD. CIGS WILL LOWER AGAIN NORTH AFT 03Z WITH POTENTIAL FOR -DZ OVER NORTH AFT 00Z. CIGS SLOWLY IMPROVE BUT REMAIN IFR/MVFR OVER MUCH OF AREA AFT 03Z. /REV && .DMX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...REV LONG TERM...KOTENBERG AVIATION...REV
AREA FORECAST DISCUSSION
NWS DULUTH MN
654 AM CST WED JAN 28 2015 .UPDATE... ISSUED AT 654 AM CST WED JAN 28 2015 ADDED SOME PATCHY FOG THIS MORNING AS SEVERAL LOCATIONS ARE REPORTING. SHOULD SEE THE FOG LIFT BY 15Z. REST OF THE FORECAST ON TRACK. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 353 AM CST WED JAN 28 2015 LOW PRESSURE WAS ORGANIZING IN THE DAKOTAS AT 08Z WITH A FRONTAL BOUNDARY EXTENDING NORTHEASTWARD INTO SOUTHERN MANITOBA AND INTO NW ONTARIO. IN THE WAA AHEAD OF THIS SYSTEM...SOME LIGHT SNOW WAS FALLING OVER THE ARROWHEAD WITH LITTLE ACCUMULATION. NORTH OF THE CANADIAN BORDER...SOME LIGHT FREEZING RAIN WAS OCCURRING RIGHT NEAR THE FRONT FROM WINNIPEG TO NEAR DRYDEN. LATEST SHORT TERM HRRR AND RAP KEEP THIS FREEZING RAIN NORTH OF THE BORDER. THE LIGHT SNOW OVER THE ARROWHEAD IS EXPECTED TO SLOWLY END BY NOON. LITTLE ADDITIONAL ACCUMULATION IS ANTICIPATED. BY THIS AFTERNOON...THE SFC LOW MOVES EASTWARD WITH THE LOW CENTER BEGINS TO REORGANIZE AND DRIFT INTO SOUTHWEST IOWA BY 00Z THURSDAY. MEANWHILE...A MID LEVEL LONG WAVE TROF MOVES OVER THE WESTERN GREAT LAKES. SOME MODEL DIFFERENCES BEGIN TO REVEL THEMSELVES WITH RESPECT TO QPF PLACEMENT AND THE AMOUNT OF COLD AIR FORECAST TO DROP INTO THE FORECAST AREA. THE GFS IS THE MOST ROBUST AND FURTHEST SOUTH WHILE THE ECMWF HAS LIMITED QPF AND KEEPS IT NEAR THE CANADIAN BORDER. HAVE USED A BLENDED APPROACH AND KEPT POPS TO THE NORTHERN HALF OF THE FORECAST AREA BY LATE AFTERNOON. PRECIPITATION TYPE WILL BE ALL SNOW. LATEST FORECAST SOUNDINGS ARE NOT SUPPORTING THE MENTION OF FREEZING RAIN OR FREEZING DRIZZLE AND HAVE REMOVED. TONIGHT...THE MID LEVEL LONG WAVE TROF MOVES EAST OF THE FORECAST AREA BY 12Z THURSDAY. THIS PUSHES THE SFC LOW EAST OF THE AREA AS WELL. BEHIND THIS SYSTEM...A TIGHTENING PRESSURE GRADIENT MOVES OVER THE WESTERN GREAT LAKES AS HIGH PRESSURE BUILDS INTO THE WESTERN DAKOTAS. MADE SOME MINOR CHANGES TO THE POPS AND THEIR TIMING ACROSS THE AREA...WITH THE SNOW ENDING LATE TONIGHT OVER THE SOUTHWEST PORTION OF THE FORECAST AREA TO THE TWIN PORTS LATE TONIGHT. FORECAST SOUNDINGS INDICATE THAT THE PRECIPITATION TYPE WILL BE ALL SNOW AND HAVE REMOVED THE MENTION FREEZING RAIN/FREEZING DRIZZLE AND SLEET. SNOW AMOUNTS WILL BE LIGHT WITH THE HIGHEST AMOUNTS OF AROUND ONE HALF INCH FOUND ALONG THE CANADIAN BORDER. ON THURSDAY...ONLY MADE SOME MINOR CHANGES TO THE POPS AND WEATHER AS MODELS ARE IN VERY GOOD AGREEMENT. WILL STILL HAVE GUSTY WINDS AS THE TIGHT PRESSURE GRADIENT REMAINS UNTIL LATE AFTERNOON WHEN THE AFOREMENTIONED HIGH PRESSURE MOVES INTO THE RED RIVER VALLEY. A NW WIND OVER LAKE SUPERIOR AND CAA WILL LEAD TO SOME LAKE EFFECT SNOW ALONG THE HIGHER TERRAIN OF THE SOUTH SHORE. SNOW AMOUNTS WILL BE LIGHT HOWEVER AS DEEP COLD AIR IS LACKING UNTIL LATE AFTERNOON. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 353 AM CST WED JAN 28 2015 MUCH COLDER AIR ON THE WAY FOR THIS WEEKEND WITH A CHANCE FOR SNOW FROM...YOU GUESSED IT...ANOTHER WEAK CLIPPER SYSTEM. THE LARGE SCALE PATTERN WILL UNDERGO SOME CHANGES THROUGH THE LONG TERM THAT WILL /AT LEAST TEMPORARILY/ PUT A STOP TO WHAT HAS BEEN A LONG PERIOD OF WEAK /AND FRANKLY DISAPPOINTING FOR SNOW LOVERS/ CLIPPERS. TEMPERATURES WILL DROP FROM WHAT HAS BEEN A VERY MILD PATTERN TO A COLDER REGIME...ENDING THE LAST WEEK OF JANUARY WITH TEMPS SIMILAR TO THE FIRST WEEK OF THE MONTH. ON THE SYNOPTIC SCALE A SERIES OF STRONG ARCTIC AIR MASSES WILL DROP DOWN INTO THE NORTHERN PLAINS AND UPPER MIDWEST. LATE THIS WEEK AN AREA OF HIGH PRESSURE WILL MOVE OVER THE AREA THURSDAY NIGHT FOLLOWED BY A WEAK CLIPPER ON FRIDAY/FRIDAY NIGHT. THEN LATE IN THE WEEKEND A DEEP LONGWAVE TROUGH AT MID-LEVELS WILL DESCEND OVER THE MIDWEST LEADING TO VERY COLD AIR ALOFT...850MB TEMPS APPROACHING THE COLDEST 10 PERCENT OF CLIMATOLOGY IN THE MID -20S C /COMPARED TO 00Z TODAY WHEN THEY WERE IN THE WARMEST 10 PERCENT OF CLIMO AT AROUND 0C/. BEST CHANCE FOR SNOWFALL ACROSS THE REGION WILL BE LATE FRIDAY AFTERNOON INTO FRIDAY NIGHT A CLIPPER MOVES ACROSS. GFS AND ECMWF IN GOOD AGREEMENT ON TIMING...WITH ECMWF PESSIMISTIC ON INTENSITY AND GFS A LITTLE STRONGER WITH A DEEPER MOISTURE PROFILE. GEM WAS SLOWER AND NOT AS INTENSE OVERALL...BUT THIS WAS A PRETTY BIG CHANGE FROM 12Z GEM WHICH WAS FASTER AND MUCH MORE AGGRESSIVE ON PRECIP. AT THIS POINT IT LOOKS LIKE A QUICK INCH OR TWO FOR NORTHERN MINNESOTA NORTH OF HIGHWAY TWO. OTHERWISE NO SIGNIFICANT CHANCES FOR PRECIP IN THE SEVEN DAY FOR MUCH OF THE REGION...WITH THE EXCEPTION OF LAKE EFFECT SNOWFALL ALONG PORTIONS OF THE SOUTH SHORE OF LAKE SUPERIOR. LAKE EFFECT SNOWFALL WILL BE PRESENT THROUGH MUCH OF THE LONG TERM PERIOD. ON THURSDAY NIGHT CONDITIONS WILL BE GOOD FOR LAKE EFFECT SNOWFALL ALONG THE HIGHER TERRAIN OF IRON/ASHLAND COUNTIES WITH STEEP LOW LEVEL LAPSE RATES THROUGH 850MB AND GREAT NORTH/NORTHWEST FLOW OVER THE LAKE. ICE COVERAGE ON THE SOUTH SHORE MAY LIMIT THE INTENSITY OF LAKE EFFECT SNOWFALL...AND OPTED TO LEAVE NORTHERN BAYFIELD COUNTY OUT OF HIGHER CHANCES FOR LAKE EFFECT SNOWFALL DUE TO WHAT WOULD BE A VERY LIMITED FETCH LENGTH. LOW LEVEL MOISTURE WILL ALSO BE A FACTOR AS NAM/GFS/ECMWF DEPICT A NEAR-SURFACE DRY LAYER...SO IT MAY TAKE A WHILE TO SATURATE LOW LEVELS AND THUS LIMIT SNOWFALL AMOUNTS. LAKE EFFECT WILL TAPER OFF AS HIGH PRESSURE MOVES OVER LAKE SUPERIOR ON FRIDAY AFTERNOON...BUT RAMP BACK UP AGAIN ON SATURDAY AND THROUGH ABOUT TUESDAY DUE TO THE VERY COLD AIRMASS THAT WILL BE IN PLACE. TEMPS WILL BE ON A DOWNWARD TREND...AND HAVE ADJUSTED SOME OF THE USUAL COLD SPOTS A LITTLE COLDER THAN INITIAL GUIDANCE TO ACCOUNT FOR THE ARCTIC HIGHS THAT WILL BE OVER NORTHEASTERN MINNESOTA IN THE LONG TERM. HIGHS IN THE MID TEENS TO MID 20S ON SATURDAY...THEN THE SINGLE DIGITS ON SUNDAY AND MONDAY BEFORE RECOVERING TO THE TEENS TUESDAY. LOWS NEAR ZERO TO TEN OR MORE BELOW ZERO ON THURSDAY NIGHT...MILD FRIDAY NIGHT DUE TO WEAK SOUTHERLY WINDS...THEN 0 TO -15 SATURDAY NIGHT AND 10 TO 20 BELOW ZERO ON SUNDAY NIGHT. MONDAY MORNING WILL BE THE COLDEST PERIOD IN THE LONG TERM WITH WIND CHILL VALUES OF 25 TO 35 BELOW ZERO...AND COLD SPOTS IN THE TIP OF THE ARROWHEAD REGION NEAR 40 BELOW ZERO. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 526 AM CST WED JAN 28 2015 GENERALLY IFR CONDITIONS THROUGH MOST OF THE TAF PERIOD AT ALL SITES DUE TO LOW CEILINGS AND PATCHY FOG DEVELOPING. AS OF THIS MORNING ALL TAF SITES EXCEPT FOR INL WERE ALREADY AT IFR CONDITIONS...WITH INL CEILINGS EXPECTED TO WORSEN LATER THIS MORNING. THERE WILL BE LITTLE IMPROVEMENT THROUGH THE DAY WITH SOME SITES POSSIBLY DETERIORATING TO LIFR CEILINGS AND IFR VISIBILITY THIS AFTERNOON. TONIGHT A COLD FRONT WILL MOVE THROUGH WHICH WILL IMPROVE CONDITIONS...WITH CEILINGS IMPROVING TO MVFR LEVELS. WINDS WILL BE LIGHT TODAY OUT OF THE SOUTH...BUT BEHIND THE COLD FRONT LATE TONIGHT WINDS WILL RAPIDLY INCREASE TO BECOME 10 TO 15 KTS OUT OF THE WEST WITH GUSTS APPROACHING/EXCEEDING 30 KTS AT TIMES. DID NOT INCLUDE STRONG WINDS IN ALL TAFS SINCE TIMING WILL BE RIGHT AROUND END OF THE TAF PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DLH 31 24 24 -1 / 10 50 10 0 INL 32 16 16 -10 / 30 60 10 0 BRD 34 22 22 5 / 10 40 0 0 HYR 33 27 27 -2 / 10 50 20 0 ASX 34 27 27 2 / 10 50 20 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...GSF SHORT TERM...GSF LONG TERM...JJM AVIATION...JJM
AREA FORECAST DISCUSSION
NWS DULUTH MN
526 AM CST WED JAN 28 2015 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 353 AM CST WED JAN 28 2015 LOW PRESSURE WAS ORGANIZING IN THE DAKOTAS AT 08Z WITH A FRONTAL BOUNDARY EXTENDING NORTHEASTWARD INTO SOUTHERN MANITOBA AND INTO NW ONTARIO. IN THE WAA AHEAD OF THIS SYSTEM...SOME LIGHT SNOW WAS FALLING OVER THE ARROWHEAD WITH LITTLE ACCUMULATION. NORTH OF THE CANADIAN BORDER...SOME LIGHT FREEZING RAIN WAS OCCURRING RIGHT NEAR THE FRONT FROM WINNIPEG TO NEAR DRYDEN. LATEST SHORT TERM HRRR AND RAP KEEP THIS FREEZING RAIN NORTH OF THE BORDER. THE LIGHT SNOW OVER THE ARROWHEAD IS EXPECTED TO SLOWLY END BY NOON. LITTLE ADDITIONAL ACCUMULATION IS ANTICIPATED. BY THIS AFTERNOON...THE SFC LOW MOVES EASTWARD WITH THE LOW CENTER BEGINS TO REORGANIZE AND DRIFT INTO SOUTHWEST IOWA BY 00Z THURSDAY. MEANWHILE...A MID LEVEL LONG WAVE TROF MOVES OVER THE WESTERN GREAT LAKES. SOME MODEL DIFFERENCES BEGIN TO REVEL THEMSELVES WITH RESPECT TO QPF PLACEMENT AND THE AMOUNT OF COLD AIR FORECAST TO DROP INTO THE FORECAST AREA. THE GFS IS THE MOST ROBUST AND FURTHEST SOUTH WHILE THE ECMWF HAS LIMITED QPF AND KEEPS IT NEAR THE CANADIAN BORDER. HAVE USED A BLENDED APPROACH AND KEPT POPS TO THE NORTHERN HALF OF THE FORECAST AREA BY LATE AFTERNOON. PRECIPITATION TYPE WILL BE ALL SNOW. LATEST FORECAST SOUNDINGS ARE NOT SUPPORTING THE MENTION OF FREEZING RAIN OR FREEZING DRIZZLE AND HAVE REMOVED. TONIGHT...THE MID LEVEL LONG WAVE TROF MOVES EAST OF THE FORECAST AREA BY 12Z THURSDAY. THIS PUSHES THE SFC LOW EAST OF THE AREA AS WELL. BEHIND THIS SYSTEM...A TIGHTENING PRESSURE GRADIENT MOVES OVER THE WESTERN GREAT LAKES AS HIGH PRESSURE BUILDS INTO THE WESTERN DAKOTAS. MADE SOME MINOR CHANGES TO THE POPS AND THEIR TIMING ACROSS THE AREA...WITH THE SNOW ENDING LATE TONIGHT OVER THE SOUTHWEST PORTION OF THE FORECAST AREA TO THE TWIN PORTS LATE TONIGHT. FORECAST SOUNDINGS INDICATE THAT THE PRECIPITATION TYPE WILL BE ALL SNOW AND HAVE REMOVED THE MENTION FREEZING RAIN/FREEZING DRIZZLE AND SLEET. SNOW AMOUNTS WILL BE LIGHT WITH THE HIGHEST AMOUNTS OF AROUND ONE HALF INCH FOUND ALONG THE CANADIAN BORDER. ON THURSDAY...ONLY MADE SOME MINOR CHANGES TO THE POPS AND WEATHER AS MODELS ARE IN VERY GOOD AGREEMENT. WILL STILL HAVE GUSTY WINDS AS THE TIGHT PRESSURE GRADIENT REMAINS UNTIL LATE AFTERNOON WHEN THE AFOREMENTIONED HIGH PRESSURE MOVES INTO THE RED RIVER VALLEY. A NW WIND OVER LAKE SUPERIOR AND CAA WILL LEAD TO SOME LAKE EFFECT SNOW ALONG THE HIGHER TERRAIN OF THE SOUTH SHORE. SNOW AMOUNTS WILL BE LIGHT HOWEVER AS DEEP COLD AIR IS LACKING UNTIL LATE AFTERNOON. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 353 AM CST WED JAN 28 2015 MUCH COLDER AIR ON THE WAY FOR THIS WEEKEND WITH A CHANCE FOR SNOW FROM...YOU GUESSED IT...ANOTHER WEAK CLIPPER SYSTEM. THE LARGE SCALE PATTERN WILL UNDERGO SOME CHANGES THROUGH THE LONG TERM THAT WILL /AT LEAST TEMPORARILY/ PUT A STOP TO WHAT HAS BEEN A LONG PERIOD OF WEAK /AND FRANKLY DISAPPOINTING FOR SNOW LOVERS/ CLIPPERS. TEMPERATURES WILL DROP FROM WHAT HAS BEEN A VERY MILD PATTERN TO A COLDER REGIME...ENDING THE LAST WEEK OF JANUARY WITH TEMPS SIMILAR TO THE FIRST WEEK OF THE MONTH. ON THE SYNOPTIC SCALE A SERIES OF STRONG ARCTIC AIR MASSES WILL DROP DOWN INTO THE NORTHERN PLAINS AND UPPER MIDWEST. LATE THIS WEEK AN AREA OF HIGH PRESSURE WILL MOVE OVER THE AREA THURSDAY NIGHT FOLLOWED BY A WEAK CLIPPER ON FRIDAY/FRIDAY NIGHT. THEN LATE IN THE WEEKEND A DEEP LONGWAVE TROUGH AT MID-LEVELS WILL DESCEND OVER THE MIDWEST LEADING TO VERY COLD AIR ALOFT...850MB TEMPS APPROACHING THE COLDEST 10 PERCENT OF CLIMATOLOGY IN THE MID -20S C /COMPARED TO 00Z TODAY WHEN THEY WERE IN THE WARMEST 10 PERCENT OF CLIMO AT AROUND 0C/. BEST CHANCE FOR SNOWFALL ACROSS THE REGION WILL BE LATE FRIDAY AFTERNOON INTO FRIDAY NIGHT A CLIPPER MOVES ACROSS. GFS AND ECMWF IN GOOD AGREEMENT ON TIMING...WITH ECMWF PESSIMISTIC ON INTENSITY AND GFS A LITTLE STRONGER WITH A DEEPER MOISTURE PROFILE. GEM WAS SLOWER AND NOT AS INTENSE OVERALL...BUT THIS WAS A PRETTY BIG CHANGE FROM 12Z GEM WHICH WAS FASTER AND MUCH MORE AGGRESSIVE ON PRECIP. AT THIS POINT IT LOOKS LIKE A QUICK INCH OR TWO FOR NORTHERN MINNESOTA NORTH OF HIGHWAY TWO. OTHERWISE NO SIGNIFICANT CHANCES FOR PRECIP IN THE SEVEN DAY FOR MUCH OF THE REGION...WITH THE EXCEPTION OF LAKE EFFECT SNOWFALL ALONG PORTIONS OF THE SOUTH SHORE OF LAKE SUPERIOR. LAKE EFFECT SNOWFALL WILL BE PRESENT THROUGH MUCH OF THE LONG TERM PERIOD. ON THURSDAY NIGHT CONDITIONS WILL BE GOOD FOR LAKE EFFECT SNOWFALL ALONG THE HIGHER TERRAIN OF IRON/ASHLAND COUNTIES WITH STEEP LOW LEVEL LAPSE RATES THROUGH 850MB AND GREAT NORTH/NORTHWEST FLOW OVER THE LAKE. ICE COVERAGE ON THE SOUTH SHORE MAY LIMIT THE INTENSITY OF LAKE EFFECT SNOWFALL...AND OPTED TO LEAVE NORTHERN BAYFIELD COUNTY OUT OF HIGHER CHANCES FOR LAKE EFFECT SNOWFALL DUE TO WHAT WOULD BE A VERY LIMITED FETCH LENGTH. LOW LEVEL MOISTURE WILL ALSO BE A FACTOR AS NAM/GFS/ECMWF DEPICT A NEAR-SURFACE DRY LAYER...SO IT MAY TAKE A WHILE TO SATURATE LOW LEVELS AND THUS LIMIT SNOWFALL AMOUNTS. LAKE EFFECT WILL TAPER OFF AS HIGH PRESSURE MOVES OVER LAKE SUPERIOR ON FRIDAY AFTERNOON...BUT RAMP BACK UP AGAIN ON SATURDAY AND THROUGH ABOUT TUESDAY DUE TO THE VERY COLD AIRMASS THAT WILL BE IN PLACE. TEMPS WILL BE ON A DOWNWARD TREND...AND HAVE ADJUSTED SOME OF THE USUAL COLD SPOTS A LITTLE COLDER THAN INITIAL GUIDANCE TO ACCOUNT FOR THE ARCTIC HIGHS THAT WILL BE OVER NORTHEASTERN MINNESOTA IN THE LONG TERM. HIGHS IN THE MID TEENS TO MID 20S ON SATURDAY...THEN THE SINGLE DIGITS ON SUNDAY AND MONDAY BEFORE RECOVERING TO THE TEENS TUESDAY. LOWS NEAR ZERO TO TEN OR MORE BELOW ZERO ON THURSDAY NIGHT...MILD FRIDAY NIGHT DUE TO WEAK SOUTHERLY WINDS...THEN 0 TO -15 SATURDAY NIGHT AND 10 TO 20 BELOW ZERO ON SUNDAY NIGHT. MONDAY MORNING WILL BE THE COLDEST PERIOD IN THE LONG TERM WITH WIND CHILL VALUES OF 25 TO 35 BELOW ZERO...AND COLD SPOTS IN THE TIP OF THE ARROWHEAD REGION NEAR 40 BELOW ZERO. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 526 AM CST WED JAN 28 2015 GENERALLY IFR CONDITIONS THROUGH MOST OF THE TAF PERIOD AT ALL SITES DUE TO LOW CEILINGS AND PATCHY FOG DEVELOPING. AS OF THIS MORNING ALL TAF SITES EXCEPT FOR INL WERE ALREADY AT IFR CONDITIONS...WITH INL CEILINGS EXPECTED TO WORSEN LATER THIS MORNING. THERE WILL BE LITTLE IMPROVEMENT THROUGH THE DAY WITH SOME SITES POSSIBLY DETERIORATING TO LIFR CEILINGS AND IFR VISIBILITY THIS AFTERNOON. TONIGHT A COLD FRONT WILL MOVE THROUGH WHICH WILL IMPROVE CONDITIONS...WITH CEILINGS IMPROVING TO MVFR LEVELS. WINDS WILL BE LIGHT TODAY OUT OF THE SOUTH...BUT BEHIND THE COLD FRONT LATE TONIGHT WINDS WILL RAPIDLY INCREASE TO BECOME 10 TO 15 KTS OUT OF THE WEST WITH GUSTS APPROACHING/EXCEEDING 30 KTS AT TIMES. DID NOT INCLUDE STRONG WINDS IN ALL TAFS SINCE TIMING WILL BE RIGHT AROUND END OF THE TAF PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DLH 31 24 24 -1 / 10 50 10 0 INL 32 16 16 -10 / 30 60 10 0 BRD 34 22 22 5 / 10 40 0 0 HYR 33 27 27 -2 / 10 50 20 0 ASX 34 27 27 2 / 10 50 20 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ SHORT TERM...GSF LONG TERM...JJM AVIATION...JJM
AREA FORECAST DISCUSSION
NWS GLASGOW MT
835 AM MST WED JAN 28 2015 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY... LOW CLOUDS AND PATCHY DENSE FOG HAS MOVED INTO THE NORTHERN ZONES THIS MORNING AND IS EXPECTED TO SPREAD INTO THE SOUTHERN ZONES THIS AFTERNOON...SANS THE FOG. TEMPS LOOK TO BE TOO HIGH SO LOWERED THEM. PRECIP IN THE NE ZONES LOOK LIGHT. FOG WILL PROBABLY LINGER INTO THE AFTERNOON. DOT CAMERAS EAST OF SCOBEY SHOWING DENSE IN PLACES. TFJ PREVIOUS DISCUSSION... A SPLIT TROUGH TEMPORARILY KNOCKED DOWN THE RIDGE LAST NIGHT. THE SOUTHERN SHORT-WAVE FEATURE WILL SEND MOISTURE THROUGH SOUTHEAST MONTANA AND WYOMING TODAY...WHILE THE NORTHERN WAVE SENDS MOISTURE EAST ACROSS CENTRAL SASKATCHEWAN. ASSOCIATED WITH THIS NORTHERN TROUGH WILL BE A COLD FRONT SENT SOUTH OVER NORTHEAST MONTANA TODAY. THE NAM AND GFS FRONTAL TIMING ARE DIFFERENT INDICATING SOME UNCERTAINTY. THE RAP HAS PICKED THE MIDDLE GROUND...SO EXPECT THE COLD FRONT TO CROSS THE INTERNATIONAL BORDER AROUND LATE MORNING. TEMPERATURES ALOFT WILL BE COOLER THAN WE HAVE EXPERIENCED FOR A WHILE...SO HIGHS WILL TREND LOWER THAN TUESDAY. A SURFACE TROUGH SETS UP TO OUR EAST WHICH WILL DEVELOP BRISK NORTHWEST WINDS OVER THE AREA TODAY...IN THE 20KT RANGE. WITH INCREASED MIXING OF STRONG WINDS ALOFT TOWARD THE SURFACE...ALSO EXPECT GUSTS TO 30KT. BY AFTERNOON THE FRONT SHOULD BE WELL INTO NORTHEAST MONTANA. LIMITED OVERRUNNING MOISTURE COULD PRODUCE SOME LIGHT PRECIPITATION. BUFKIT SUGGESTS PRECIPITATION TYPE TO BE FREEZING RAIN OR RAIN IN THE MORNING AND RAIN IN THE AFTERNOON. SLIGHT CHANCE POPS WILL BE LIMITED TO THE EASTERN ZONES. TONIGHT...THE COLD BOUNDARY ONCE AGAIN SETS UP NW TO SE ACROSS THE CWA. THE OVERRUNNING MOISTURE WILL CREATE LOW STRATUS OVER THE EASTERN ZONES...AND POSSIBLY A LITTLE MORE LIGHT INTERMITTENT PRECIPITATION IN THE EVENING. INCREASING HIGH SURFACE PRESSURE FROM THE NORTH WILL DIMINISH NW WIND SIGNIFICANTLY. THURSDAY THROUGH FRIDAY...FLOW ALOFT CONTINUES FROM THE NORTHWEST AS THE STATIONARY BOUNDARY WANDERS AROUND JUST NORTHEAST OF OUR AREA. 850MB TEMPERATURES WILL REMAIN NEAR 0C WHICH WILL BE MUCH COOLER THAN THE LAST SEVERAL DAYS. MODELS CONTINUE TO DIFFER WITH EXPECTED SURFACE TEMPERATURES. BUT UNTIL THE STATIONARY FRONT DROPS SOUTH AGAIN TEMPERATURES WILL CONTINUE ABOVE NORMAL BY AROUND 15F-20F. SCT .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY... PERSISTENT LONG WAVE UPPER LEVEL RIDGE HANGS OVER PACIFIC NORTHEAST REGION THROUGHOUT EXTENDED FORECAST PERIOD. RIDGE AXIS SLOWLY RETROGRADES WESTWARD AS UPPER LEVEL HUDSON BAY LOW DEEPENS LATER IN THE WEEKEND. TEMPERATURES WILL SLOWLY COOL TO BELOW SEASONAL NORMALS SUNDAY AND MONDAY. BY WEDNESDAY RIDGE REESTABLISHES ITS INFLUENCE OVER THE AREA FOR A RETURN TO NEAR NORMAL TEMPERATURES. SEVERAL SHORTWAVES SWEEP THROUGH THE NORTHWEST FLOW ALOFT FOR A SLIGHT CHANCE OF SHOWERS...WITH BEST CHANCES SATURDAY AFTERNOON AND EVENING. WEAK SURFACE PRESSURE GRADIENTS WILL RESULT IN RELATIVELY LIGHT WINDS THROUGH PERIOD. BRITTON && .AVIATION... FLIGHT CATEGORY: MVFR. CIGS AND VSBY: MVFR WITH IFR CEILINGS ARE EXPECTED TODAY AS LOW CLOUDS ARE MOVING SOUTHEAST INTO THE AREA. PATCHY DENSE FOG HAS BEEN OBSERVED ON THE RIDGE TOPS. VALLEY AIRPORTS SHOULD ESCAPE MUCH OF THE FOG. WIND: WINDS WILL INCREASE THROUGH THE DAY FROM THE NW. TFJ && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
521 AM MST WED JAN 28 2015 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY... A SPLIT TROUGH TEMPORARILY KNOCKED DOWN THE RIDGE LAST NIGHT. THE SOUTHERN SHORT-WAVE FEATURE WILL SEND MOISTURE THROUGH SOUTHEAST MONTANA AND WYOMING TODAY...WHILE THE NORTHERN WAVE SENDS MOISTURE EAST ACROSS CENTRAL SASKATCHEWAN. ASSOCIATED WITH THIS NORTHERN TROUGH WILL BE A COLD FRONT SENT SOUTH OVER NORTHEAST MONTANA TODAY. THE NAM AND GFS FRONTAL TIMING ARE DIFFERENT INDICATING SOME UNCERTAINTY. THE RAP HAS PICKED THE MIDDLE GROUND...SO EXPECT THE COLD FRONT TO CROSS THE INTERNATIONAL BORDER AROUND LATE MORNING. TEMPERATURES ALOFT WILL BE COOLER THAN WE HAVE EXPERIENCED FOR A WHILE...SO HIGHS WILL TREND LOWER THAN TUESDAY. A SURFACE TROUGH SETS UP TO OUR EAST WHICH WILL DEVELOP BRISK NORTHWEST WINDS OVER THE AREA TODAY...IN THE 20KT RANGE. WITH INCREASED MIXING OF STRONG WINDS ALOFT TOWARD THE SURFACE...ALSO EXPECT GUSTS TO 30KT. BY AFTERNOON THE FRONT SHOULD BE WELL INTO NORTHEAST MONTANA. LIMITED OVERRUNNING MOISTURE COULD PRODUCE SOME LIGHT PRECIPITATION. BUFKIT SUGGESTS PRECIPITATION TYPE TO BE FREEZING RAIN OR RAIN IN THE MORNING AND RAIN IN THE AFTERNOON. SLIGHT CHANCE POPS WILL BE LIMITED TO THE EASTERN ZONES. TONIGHT...THE COLD BOUNDARY ONCE AGAIN SETS UP NW TO SE ACROSS THE CWA. THE OVERRUNNING MOISTURE WILL CREATE LOW STRATUS OVER THE EASTERN ZONES...AND POSSIBLY A LITTLE MORE LIGHT INTERMITTENT PRECIPITATION IN THE EVENING. INCREASING HIGH SURFACE PRESSURE FROM THE NORTH WILL DIMINISH NW WIND SIGNIFICANTLY. THURSDAY THROUGH FRIDAY...FLOW ALOFT CONTINUES FROM THE NORTHWEST AS THE STATIONARY BOUNDARY WANDERS AROUND JUST NORTHEAST OF OUR AREA. 850MB TEMPERATURES WILL REMAIN NEAR 0C WHICH WILL BE MUCH COOLER THAN THE LAST SEVERAL DAYS. MODELS CONTINUE TO DIFFER WITH EXPECTED SURFACE TEMPERATURES. BUT UNTIL THE STATIONARY FRONT DROPS SOUTH AGAIN TEMPERATURES WILL CONTINUE ABOVE NORMAL BY AROUND 15F-20F. SCT .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY... PERSISTENT LONG WAVE UPPER LEVEL RIDGE HANGS OVER PACIFIC NORTHEAST REGION THROUGHOUT EXTENDED FORECAST PERIOD. RIDGE AXIS SLOWLY RETROGRADES WESTWARD AS UPPER LEVEL HUDSON BAY LOW DEEPENS LATER IN THE WEEKEND. TEMPERATURES WILL SLOWLY COOL TO BELOW SEASONAL NORMALS SUNDAY AND MONDAY. BY WEDNESDAY RIDGE REESTABLISHES ITS INFLUENCE OVER THE AREA FOR A RETURN TO NEAR NORMAL TEMPERATURES. SEVERAL SHORTWAVES SWEEP THROUGH THE NORTHWEST FLOW ALOFT FOR A SLIGHT CHANCE OF SHOWERS...WITH BEST CHANCES SATURDAY AFTERNOON AND EVENING. WEAK SURFACE PRESSURE GRADIENTS WILL RESULT IN RELATIVELY LIGHT WINDS THROUGH PERIOD. BRITTON && .AVIATION... FLIGHT CATEGORY: VFR. SYNOPSIS: AN UPPER-LEVEL RIDGE OF HIGH PRESSURE PERSISTS OVER THE REGION TODAY AND WILL ALLOW FOR SOME HIGH CLOUDINESS. CIGS AND VSBY: VFR CIGS AND VSBY WILL CONTINUE THROUGH PERIOD. WIND: WINDS WILL INCREASE THROUGH THE DAY ON WEDNESDAY. BRITTON && .HYDROLOGY... DUE TO THE RECENT WARM TEMPERATURES SOME OF THE CREEKS AND SMALL STREAMS HAVE BEGUN TO RUN. MINOR FLOODING WAS REPORTED AT 7 MILE CREEK NEAR GLENDIVE WHICH PROMPTED THE ISSUANCE OF A SMALL STREAM FLOOD ADVISORY THROUGH EARLY MORNING. TEMPERATURES ARE EXPECTED TO TREND LOWER TOWARDS NORMAL BY THE WEEKEND WHICH WILL WILL BEGIN TO LIMIT ANY FURTHER FLOODING. && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
307 AM MST WED JAN 28 2015 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY... A SPLIT TROUGH TEMPORARILY KNOCKED DOWN THE RIDGE LAST NIGHT. THE SOUTHERN SHORT-WAVE FEATURE WILL SEND MOISTURE THROUGH SOUTHEAST MONTANA AND WYOMING TODAY...WHILE THE NORTHERN WAVE SENDS MOISTURE EAST ACROSS CENTRAL SASKATCHEWAN. ASSOCIATED WITH THIS NORTHERN TROUGH WILL BE A COLD FRONT SENT SOUTH OVER NORTHEAST MONTANA TODAY. THE NAM AND GFS FRONTAL TIMING ARE DIFFERENT INDICATING SOME UNCERTAINTY. THE RAP HAS PICKED THE MIDDLE GROUND...SO EXPECT THE COLD FRONT TO CROSS THE INTERNATIONAL BORDER AROUND LATE MORNING. TEMPERATURES ALOFT WILL BE COOLER THAN WE HAVE EXPERIENCED FOR A WHILE...SO HIGHS WILL TREND LOWER THAN TUESDAY. A SURFACE TROUGH SETS UP TO OUR EAST WHICH WILL DEVELOP BRISK NORTHWEST WINDS OVER THE AREA TODAY...IN THE 20KT RANGE. WITH INCREASED MIXING OF STRONG WINDS ALOFT TOWARD THE SURFACE...ALSO EXPECT GUSTS TO 30KT. BY AFTERNOON THE FRONT SHOULD BE WELL INTO NORTHEAST MONTANA. LIMITED OVERRUNNING MOISTURE COULD PRODUCE SOME LIGHT PRECIPITATION. BUFKIT SUGGESTS PRECIPITATION TYPE TO BE FREEZING RAIN OR RAIN IN THE MORNING AND RAIN IN THE AFTERNOON. SLIGHT CHANCE POPS WILL BE LIMITED TO THE EASTERN ZONES. TONIGHT...THE COLD BOUNDARY ONCE AGAIN SETS UP NW TO SE ACROSS THE CWA. THE OVERRUNNING MOISTURE WILL CREATE LOW STRATUS OVER THE EASTERN ZONES...AND POSSIBLY A LITTLE MORE LIGHT INTERMITTENT PRECIPITATION IN THE EVENING. INCREASING HIGH SURFACE PRESSURE FROM THE NORTH WILL DIMINISH NW WIND SIGNIFICANTLY. THURSDAY THROUGH FRIDAY...FLOW ALOFT CONTINUES FROM THE NORTHWEST AS THE STATIONARY BOUNDARY WANDERS AROUND JUST NORTHEAST OF OUR AREA. 850MB TEMPERATURES WILL REMAIN NEAR 0C WHICH WILL BE MUCH COOLER THAN THE LAST SEVERAL DAYS. MODELS CONTINUE TO DIFFER WITH EXPECTED SURFACE TEMPERATURES. BUT UNTIL THE STATIONARY FRONT DROPS SOUTH AGAIN TEMPERATURES WILL CONTINUE ABOVE NORMAL BY AROUND 15F-20F. SCT .LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY... PERSISTENT LONG WAVE UPPER LEVEL RIDGE HANGS OVER PACIFIC NORTHEAST REGION THROUGHOUT EXTENDED FORECAST PERIOD. RIDGE AXIS SLOWLY RETROGRADES WESTWARD AS UPPER LEVEL HUDSON BAY LOW DEEPENS LATER IN THE WEEKEND. TEMPERATURES WILL SLOWLY COOL TO BELOW SEASONAL NORMALS SUNDAY AND MONDAY. BY WEDNESDAY RIDGE REESTABLISHES ITS INFLUENCE OVER THE AREA FOR A RETURN TO NEAR NORMAL TEMPERATURES. SEVERAL SHORTWAVES SWEEP THROUGH THE NORTHWEST FLOW ALOFT FOR A SLIGHT CHANCE OF SHOWERS...WITH BEST CHANCES SATURDAY AFTERNOON AND EVENING. WEAK SURFACE PRESSURE GRADIENTS WILL RESULT IN RELATIVELY LIGHT WINDS THROUGH PERIOD. BRITTON && .AVIATION... FLIGHT CATEGORY: VFR. SYNOPSIS: AN UPPER-LEVEL RIDGE OF HIGH PRESSURE PERSISTS OVER THE REGION TODAY AND WILL ALLOW FOR A FEW HIGH CHINOOK ARCH CLOUDS. THEN AN UPPER-LEVEL SHORT WAVE SWINGS ACROSS NORTHERN MONTANA AFTER 00Z. CIGS AND VSBY: VFR CIGS AND VSBY WILL CONTINUE THROUGH 18Z THEN A CHANCE FOR MVFR CIGS OVER THE NORTHEASTERN 1/3RD FOR THE FORECAST AREA. WIND: LIGHT WIND WILL SHIFT TO THE NORTHWEST OVERNIGHT AND THEN INCREASE THROUGH THE DAY ON WEDNESDAY. PROTON && .HYDROLOGY... DUE TO THE RECENT WARM TEMPERATURES SOME OF THE CREEKS AND SMALL STREAMS HAVE BEGUN TO RUN. MINOR FLOODING WAS REPORTED AT 7 MILE CREEK NEAR GLENDIVE WHICH PROMPTED THE ISSUANCE OF A SMALL STREAM FLOOD ADVISORY FOR THROUGH EARLY MORNING. TEMPERATURES ARE EXPECTED TO TREND LOWER TOWARDS NORMAL BY THE WEEKEND WHICH WILL WILL BEGIN TO LIMIT ANY FURTHER FLOODING. && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS HASTINGS NE
540 AM CST WED JAN 28 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 344 AM CST WED JAN 28 2015 BEEN ANOTHER QUIET NIGHT ACROSS THE AREA...THANKS TO AN UPPER LEVEL SHORTWAVE RIDGE AXIS THAT HAS BEEN STEADILY MAKING ITS WAY EAST THROUGH THE PLAINS...PUSHED BY AN UPPER LEVEL DISTURBANCE MOVING INTO WRN PORTIONS OF WY. AT THE SURFACE...THE PATTERN OVER THE CWA IS ONCE AGAIN ON THE WEAKER SIDE...WITH A TROUGH AXIS SET UP OVER THE HIGH PLAINS...RESULTING IN LIGHT AND AT TIMES VARIABLE WINDS. TEMPS EARLY THIS MORNING AT 3 AM RANGE ANYWHERE FROM THE MID 20S IN THE NORTH TO MID 40S IN THE FAR SWRN CORNER OF THE CWA. THE MAIN STORY THROUGH THE SHORT TERM PERIOD LIES WITH THAT UPPER LEVEL DISTURBANCE PUSHING INTO WY THIS MORNING...AND THE ACCOMPANYING FRONTAL BOUNDARY IT WILL PUSH THROUGH THE CWA. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE TIMING OF THIS DISTURBANCE...SHOWING IT MOVING INTO THE NEB PANHANDLE NEAR MIDDAY TODAY...BY 00Z THIS EVENING THE TROUGH AXIS LOOKS TO BE EXTENDING THROUGH THE HEART OF THE CWA...BEFORE PUSHING OFF TO THE MISSOURI RIVER AREA BY MIDNIGHT TONIGHT. A WEAKER SECOND MID LEVEL DISTURBANCE QUICK ON THE HEELS OF THE MAIN ONE IS FORECAST TO BE WORKING INTO THE AREA AS WE GET INTO THE EARLY MORNING HOURS THURSDAY. EVEN WITH THERE ACTUALLY BEING A SYSTEM TO TALK ABOUT...MODELS /INCLUDING THE MORE SHORT TERM HIRES LIKE THE WRF/ OVERALL CONTINUE TO BE IN GOOD AGREEMENT SHOWING CONDITIONS REMAINING DRY...JUST NOT A LOT OF MOISTURE TO WORK WITH. THAT BEING SAID...SOME MODELS ARE HINTING AT THE POTENTIAL OF SOME VERY LIGHT PRECIP FALLING THIS EVENING/OVERNIGHT...BUT KEEP THAT SIGNAL JUST OUTSIDE THE N/NERN BORDERS OF THE CWA. WILL BE SOMETHING FOR THE DAY SHIFT TO MONITOR WITH THE 12Z RUN OF MODELS THIS MORNING. AT THE SFC...WINDS WILL REMAIN ON THE LIGHTER SIDE THIS MORNING...BEFORE THE WIND SHIFT OF THE COLD FRONT ACCOMPANYING THIS SYSTEM PASSES THROUGH THE CWA...WHICH MODELS SHOW PUSHING ABOUT HALFWAY THROUGH THE CWA BY MID MORNING AND MAKING IT TO THE ERN FRINGE OF THE CWA AROUND MIDDAY. THIS WILL USHER IN A PUSH OF GUSTY W/NWRLY WINDS /15 TO 25 MPH IS FORECAST/...BUT THE MAIN PUSH OF COLDER AIR IS LAGGING BEHIND. TEMPS ALOFT COOL A TOUCH DURING THE DAY...BUT HIGHS ARE STILL FORECAST TO BE WELL ABOVE AVERAGE...THANKS TO THE MILD AIR/DOWNSLOPING WINDS. NOT EXPECTED TO BE AS WARM AS TUESDAY...BUT TRENDED HIGHS TOWARD THE MAV AND RAP /WHICH DID PRETTY WELL TUESDAY/...WHICH PUTS THE MAJORITY OF THE CWA AT LEAST INTO THE MID 60S /THE EXCEPTION AGAIN IS THE E/NERN PORTIONS/...WITH HIGHS NEAR 70 FORECAST IN NC KS. IF TEMPS PAN OUT AS FORECAST...IT WOULD SET A NEW RECORD HIGH TEMPS IN GRAND ISLAND. BUT CONFIDENCE ISNT THE HIGHEST...AS THERE ARE MODELS THAT SAY IT WILL FALL SHORT OF/MAYBE TIE THE RECORD OF 63 DEGREES. THE RECORD AT HASTINGS IS 69 DEGREES...AND THE RAP IS BASICALLY THE ONLY ONE SHOWING THE POTENTIAL FOR TEMPS TO MAKE A RUN AT THAT RECORD. FIRE WX CONCERNS ARISE AGAIN...SEE FIRE WEATHER SECTION BELOW FOR ADDITIONAL INFORMATION. THIS EVENING/TONIGHT...ONE MIGHT THINK THAT WINDS WE HAVE THIS AFTERNOON WOULD TAPER OFF...BUT WITH THE MAIN PUSH OF COLD AIR ADVECTION...BETTER PRESSURE RISES/TIGHTER PRESSURE GRADIENT...AND STRONGER WINDS ALOFT TO TAP INTO...THATS NOT THE CASE. MADE SOME ADJUSTMENTS TO WIND SPEEDS...WHICH WILL BE ON A SECOND INCREASE THIS EVENING...AND BY MIDNIGHT TONIGHT SPEEDS IN THE 25 TO 30 MPH RANGE WILL BE POSSIBLE...MAINLY ACROSS OUR SC NEB COUNTIES. LOOKS TO REMAIN BREEZY INTO THE EARLY MORNING HOURS THURSDAY. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 344 AM CST WED JAN 28 2015 GUIDANCE SUGGESTS AN UPPER TROPOSPHERIC SHORT WAVE WILL BE NOTED OVER THE MID-MISSISSIPPI VALLEY TO START THE LONG-TERM FORECAST PERIOD AT 12Z THURSDAY...THUS HELPING PROVIDE NORTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA. THIS NORTHWESTERLY FLOW IS EXPECTED TO PERSIST OVER OUR AREA THURSDAY INTO THURSDAY NIGHT BEFORE THE APPROACH OF AN UPPER TROPOSPHERIC LONGWAVE TROUGH AXIS PROMOTES QUASI-ZONAL TO SOUTHWESTERLY UPPER TROPOSPHERIC FLOW FRIDAY THROUGH SATURDAY. THIS UPPER TROPOSPHERIC TROUGH AXIS IS EXPECTED TO CLEAR OUR AREA SATURDAY NIGHT...THUS ALLOWING FOR NORTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA AS WE HEAD INTO THE EARLY PART OF NEXT WEEK. GUIDANCE SUGGESTS AN OVERALL LACK IN OMEGA WILL KEEP US DRY THURSDAY...THURSDAY NIGHT AND THROUGH THE DAY FRIDAY...AND SUCH HAS BEEN PRESENTED IN THE OFFICIAL FORECAST. STARTING FRIDAY NIGHT AND CONTINUING INTO SATURDAY...SATURDAY NIGHT AND PERHAPS EARLY SUNDAY...UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH AXIS IS EXPECTED TO PROMOTE ENOUGH OMEGA FOR PRECIPITATION PRODUCTION ACROSS MUCH OF THE REGION...INCLUDING OUR CWA. THE OPERATIONAL GFS AND EC CONTINUE TO COME INTO BETTER AGREEMENT BY SUGGESTING PRECIPITATION WILL MOVE IN FROM SOUTHWEST TO NORTHEAST ACROSS MUCH OF OUR AREA...AGAIN BEGINNING FRIDAY NIGHT...WITH WIDESPREAD PRECIPITATION THEN CONTINUING ACROSS THE AREA SATURDAY AND SATURDAY NIGHT BEFORE MOVING EAST...ALONG THE UPPER TROPOSPHERIC TROUGH AXIS...AROUND OR SHORTLY AFTER SUNRISE SUNDAY. INTERESTING TO NOTE THAT THE NAM...WHICH THROUGH 84 HOURS IS JUST NOW UP TO 12Z SATURDAY...APPEARS TO KEEP THE PRIMARY AXIS OF OMEGA WELL TO OUR SOUTHEAST AND AS A RESULT...KEEPS US DRY THROUGH 12Z SATURDAY. ALTHOUGH IT WILL BE VERY INTERESTING TO SEE HOW THE NAM UNFOLDS THROUGH THE NEXT FEW RUNS...GIVEN THE AFOREMENTIONED DATA FROM THE OPERATIONAL GFS AND EC...IT SEEMS PRUDENT TO PRESENT YET ANOTHER INCREASE IN POPS FOR THIS WEEKEND AND 30-60% POPS ARE NOW SHOWN IN THE OFFICIAL FORECAST...WITH THE HIGHEST POPS RELEGATED TO OUR SOUTHEAST WHICH IS WHERE GUIDANCE SUGGESTS THE STRONGEST OMEGA AND MOST EFFICIENT PRECIPITATION PRODUCTION WILL RESIDE DURING THIS UPCOMING STORM SYSTEM. ONCE PRECIPITATION COMES TO AN END ON SUNDAY...GUIDANCE SUGGESTS DRY CONDITIONS SHOULD BE OBSERVED SUNDAY NIGHT THROUGH TUESDAY...AND SUCH HAS BEEN PRESENTED IN THE OFFICIAL FORECAST. ALTHOUGH IT APPEARS PRECIPITATION COULD START OUT AS RAIN FRIDAY NIGHT...FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE OPERATIONAL GFS AND EC...SUGGEST THE LOWER TROPOSPHERE WILL BE SUPPORTIVE FOR SNOWFALL AT THE SURFACE BY 12Z SATURDAY AND CONTINUING INTO SUNDAY. THAT SAID...WITH A CONTINUED SOUTH/SOUTHEASTERLY BOUNDARY- LAYER WIND FIELD EXPECTED THROUGH THE DAY SATURDAY...THERE IS STILL AT LEAST AN OPPORTUNITY FOR SOME TEMPERATURE RECOVERY NEAR THE SURFACE DURING THE DAY SATURDAY AND SUPERBLEND RESPONDED BY PROVIDING SATURDAY HIGHS IN THE UPPER 30S AND LOW 40S. THERE ARE SUGGESTIONS FROM MULTIPLE SETS OF GUIDANCE THAT THIS TEMPERATURE FORECAST FOR SATURDAY IS TOO HIGH AND NEEDS TO BE REDUCED BY 4-5 DEGREES. WENT AHEAD WITH A ~2 DEGREE DECREASE FROM THE SUPERBLEND SOLUTION FOR SATURDAY HIGHS TO ACCOUNT OF THIS...BUT EVEN NOW THE OFFICIAL FORECAST CALLS FOR SATURDAY TEMPERATURE READINGS IN THE UPPER 30S FOR MOST LOCATIONS AND GIVEN THIS...DESPITE FORECAST PROXIMITY SOUNDINGS FROM THE OPERATIONAL GFS AND EC SUGGESTING SNOWFALL WILL BE THE PRIMARY PRECIPITATION TYPE DURING THE DAY SATURDAY...FIND IT HARD TO JUSTIFY AN ALL-SNOW FORECAST WITH SURFACE TEMPERATURE READINGS SO HIGH. AS A RESULT...OPTED TO GO WITH A RAIN AND SNOW MIX DURING THE DAY SATURDAY...WITH ALL SNOW THEN EXPECTED SATURDAY NIGHT INTO SUNDAY AS DIABATIC HEATING IS LOST AND A BOUNDARY-LAYER BAROCLINIC ZONE CLEARS THE AREA. OBVIOUSLY THE TEMPERATURE FORECAST FOR SATURDAY WILL NEED TO BE CLOSELY MONITORED AS ANY MORE OF A DECREASE IN SATURDAYS TEMPERATURE FORECAST WOULD SUGGEST MORE SNOW THAN RAIN DURING THE DAY SATURDAY...AND MORE IN THE WAY OF SNOW ACCUMULATION. OBVIOUSLY STORM-TOTAL SNOWFALL ACCUMULATION WILL BE HEAVILY DEPENDENT UPON HOW MUCH SNOWFALL IS REALIZED DURING THE DAY SATURDAY...AND GIVEN THE UNCERTAINTY WITH RESPECT TO PRECIPITATION TYPE AND RESULTANT SNOW ACCUMULATION DURING THE DAY SATURDAY...IT STILL REMAINS TOO EARLY TO GET SPECIFIC ON SNOW AMOUNTS IN THE OFFICIAL FORECAST. THAT SAID...ONCE AGAIN TAKING THE OPERATIONAL GFS AND EC AT FACE VALUE SUGGESTS ADVISORY-WORTHY ACCUMULATION OF ~3 INCHES COULD BE REALIZED ACROSS PORTIONS OF THE CWA SATURDAY NIGHT INTO EARLY SUNDAY MORNING ALONE...DESPITE WHAT HAPPENS DURING THE DAY SATURDAY. IN ADDITION...GUIDANCE IS NOW SUGGESTING THAT AN INCREASING PRESSURE GRADIENT POST-FROPA SATURDAY NIGHT INTO SUNDAY WILL PROMOTE A STRONG WIND...SUSTAINED AT AROUND 18KTS WITH HIGHER GUSTS. THIS WIND...WORKING IN CONCERT WITH THE SNOWFALL...WOULD LIKELY CREATE AT LEAST PERIODIC VISIBILITY RESTRICTION IN BLOWING SNOW. SO...GIVEN THE FACT THAT WE NOW HAVE "LIKELY" POPS IN THE FORECAST FOR PORTIONS OF THE AREA THIS WEEKEND...AND THE FACT THAT IT NOW APPEARS WE HAVE AN OPPORTUNITY FOR BLOWING SNOW AND VISIBILITY RESTRICTION...FEEL IT PRUDENT TO INTRODUCE A MENTION OF ACCUMULATING SNOWFALL AND VISIBILITY RESTRICTION DUE TO BLOWING SNOW FOR THIS WEEKEND IN THE HWO. FINALLY...HIGHS TO START THE LONG-TERM FORECAST PERIOD ON THURSDAY AND FRIDAY ARE STILL EXPECTED TO CLIMB INTO THE 40S...BUT WILL FALL INTO THE 20S POST-FROPA STARTING EARLY NEXT WEEK. OVERNIGHT LOWS IN THE 20S AND 30S ARE ALSO EXPECTED TO START THE LONG-TERM FORECAST PERIOD...BUT THESE READINGS WILL LIKELY FALL INTO THE SINGLE DIGITS AND TEENS EARLY NEXT WEEK AS WELL. && .AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 535 AM CST WED JAN 28 2015 MAIN FORECAST CONCERN FOR THIS TAF PERIOD LIES WITH WINDS. WINDS REMAIN ON THE LIGHT AND AT TIMES VARIABLE SIDE EARLY THIS MORNING THANKS TO A WEAKER SURFACE PATTERN IN PLACE...AND AT LEAST FOR A FEW MORE HOURS WILL REMAIN THAT WAY. DEBATED THROWING IN A MENTION OF LLWS FOR A FEW HOURS...BUT MODELS KEEP THE STRONGER WINDS ALOFT TO THE WEST OF THE TERMINAL AREAS...SO KEPT OUT OF THIS TAF. THIS MORNING...A FRONTAL BOUNDARY SHIFTING EAST WILL BRING MORE WESTERLY WINDS TO THE AREA...THEN BECOMING NORTHWESTERLY THIS AFTERNOON AND CONTINUING THROUGH THE END OF THE TAF PERIOD. SPEEDS WILL ALSO BE ON THE INCREASE...WITH SUSTAINED SPEEDS OF 15 TO 25 MPH EXPECTED THIS AFTERNOON...AND 25 TO 30 MPH WINDS WILL BE POSSIBLE THROUGH AT LEAST THE EVENING HOURS...BUT WILL REMAIN GUSTY THROUGH THE END OF THE PERIOD. MODELS ALSO SUGGEST THE POTENTIAL FOR SOME LOWER CEILINGS ACCOMPANYING THE COLDER AIR PUSH TONIGHT...SO INSERTED MVFR CEILINGS AT BOTH TERMINALS. && .FIRE WEATHER... ISSUED AT 344 AM CST WED JAN 28 2015 GUSTY W/NW WINDS ARE EXPECTED TO DEVELOP ACROSS THE CWA DURING THE DAYTIME HOURS TODAY...AND ABOVE AVERAGE TEMPERATURES ARE ONCE AGAIN FORECAST. HIGH TEMPERATURES REACHING WELL INTO THE 60S TO NEAR 70 DEGREES IN SOME LOCATIONS...COMBINED WITH DEWPOINTS FORECAST TO FALL TO NEAR 30 DEGREES WILL RESULT IN NEAR CRITICAL FIRE WEATHER CONDITIONS ACROSS PORTIONS OF THE CWA. THE BEST CHANCE FOR RELATIVE HUMIDITY VALUES TO FALL INTO THE 20 TO 25 MPH RANGE WITH THOSE GUSTY WINDS WILL LIE ACROSS AREAS GENERALLY ALONG AND WEST OF A LEXINGTON NEB TO BELOIT KS LINE. && .CLIMATE... ISSUED AT 331 AM CST TUE JAN 27 2015 YET ANOTHER DAY WITH FORECAST HIGHS WELL ABOVE AVERAGE IS EXPECTED TODAY. AVERAGE HIGHS FOR THIS TIME OF YEAR ARE MAINLY IN THE MID 30S...WITH HIGHS FORECAST TODAY TO REACH INTO THE 60S /NEAR 70 POSSIBLE ACROSS SRN LOCATIONS/. HERE IS THE RECORD HIGH TEMPERATURE INFORMATION FOR TODAY...WITH GRAND ISLAND CURRENTLY FORECAST TO BREAK THAT RECORD...BUT HASTINGS FORECAST TO FALL A BIT SHORT. GRAND ISLAND: RECORD IS 63 DEGREES IN 1986. FORECAST HIGH: 65 HASTINGS: RECORD IS 69 DEGREES IN 1931. FORECAST HIGH: 65 && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ADP LONG TERM...BRYANT AVIATION...ADP FIRE WEATHER...ADP CLIMATE...ADP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
630 AM CST WED JAN 28 2015 .UPDATE... ISSUED AT 630 AM CST WED JAN 28 2015 NO UPDATES OTHER THAN TO UPDATE TEMPERATURES BASED ON LATEST 6 AM OBSERVATIONS. UPDATE ISSUED AT 546 AM CST WED JAN 28 2015 BASED ON TRENDS VIA OBSERVATIONS AND SATELLITE IMAGERY...WILL LEAN ON HRRR GUIDANCE (WHICH IS DOING VERY WELL) AND EXPAND FOG WORDING WEST AND SOUTH AND WILL ALSO EXPAND THE DENSE FOG ADVISORY FARTHER WEST. ALSO EXTENDED TILL 18Z FOR HEADLINE CUTOFF. UPDATE ISSUED AT 344 AM CST WED JAN 28 2015 WILL GO WITH A DENSE FOG ADVISORY EAST. OBSERVATIONS NOT GETTING ANY BETTER AND AREA WEB CAMS SHOWING WORSE VISIBILITIES NOW. UPDATED PRODUCTS OUT SOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CST WED JAN 28 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE COOLER TEMPERATURES...BREEZY CONDITIONS...AND CHANCES FOR LIGHT SNOW TODAY AND TONIGHT. CURRENTLY...ZONAL FLOW ALOFT WITH THE UPPER LEVEL RIDGE FLATTENING ACROSS THE GREAT PLAINS IN RESPONSE TO SOUTHERN AND NORTHERN STREAM S/WV`S CROSSING THE ROCKIES. SURFACE LOW PRESSURE ASSOCIATED WITH THE SOUTHERN STREAM WAVE MOVING SOUTHEAST ACROSS SOUTHWEST NORTH DAKOTA INTO CENTRAL SOUTH DAKOTA. SOUTH/SOUTHEASTERLY RETURN FLOW AHEAD OF THE LOW HAS MAINTAINED LOW STRATUS AND/OR FOG ACROSS EASTERN NORTH DAKOTA SINCE YESTERDAY EVENING. LARGE STRATUS FIELD WRAPS BACK WESTWARD ACROSS SOUTH CENTRAL CANADA WITH THE SOUTHERN EDGE OF THE STRATUS ALONG TO SLIGHTLY NORTH OF THE INTERNATIONAL BORDER. VISIBILITIES CONTINUE TO FLUCTUATE ACROSS MY EAST...AND WILL HANDLE THE PATCHY DENSE FOG WITH THE CURRENT SPECIAL WEATHER STATEMENT. AS THE SURFACE LOW CONTINUES SOUTHEAST TODAY...SURFACE WINDS BECOME MORE NORTHWESTERLY AND INCREASE THROUGH THE MORNING INTO THE AFTERNOON BEHIND A STRONG SFC COLD FRONT. BUFKIT ANALYSIS BRINGS 35 TO NEAR 40KTS WITHIN THE TOP OF THE MIXED LAYER TO MOST SITES...SO WHILE BREEZY...SUB-ADVISORY MAGNITUDES. THUS NO HEADLINES WITH THIS FORECAST ISSUANCE. STRATUS TO OUR NORTH SURGES SOUTH ALONG WITH CAA WITH MOST OF REGION CLOUDED OVER BY EARLY TO MID AFTERNOON. CLOUD COVER AND BREEZY CONDITIONS WILL THEN CONTINUE INTO WEDNESDAY NIGHT. POST FRONTAL SNOW SHOWERS DEVELOP LATER THIS MORNING NORTH THEN SOUTHWARD THIS AFTERNOON CONTINUING TONIGHT. KEPT POPS AT SLIGHT CHANCE FOR NOW...BUT MAY NEED TO BE INCREASED. FOR TEMPERATURES...DESPITE CAA AND CLOUD COVER...THE INCREASED MIXING WITH THE BREEZY NORTHWEST WIND WILL ACTUALLY KEEP TEMPERATURES FROM BOTTOMING OUT TOO MUCH TODAY. DAYTIME HIGHS WILL BE COOLER THAN TUESDAY...RANGING FROM THE LOW 30S NORTH TO MID/UPPER 40S SOUTHWEST. SO ABOUT 5-15 DEGREES COOLER. CLOUD COVER AND CONTINUED MIXING TONIGHT SHOULD ALSO KEEP LOWS FROM DROPPING TOO MUCH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 315 AM CST WED JAN 28 2015 CHANCES FOR SNOW SATURDAY AND COOLER TEMPERATURES THROUGH THE WEEKEND AND INTO NEXT WEEK WILL HIGHLIGHT THE LONG TERM. AN UPPER LEVEL TROUGH MOVING SOUTHEAST FROM ALBERTA LATE FRIDAY INTO EARLY SATURDAY MORNING WILL BRING A CHANCE OF SNOW THROUGH SATURDAY NIGHT...ALONG WITH COLDER TEMPERATURES. THERE IS GOOD AGREEMENT BETWEEN THE GFS/ECMWF IN THE OVERALL TIMING/LOCATION OF THE UPPER LEVEL TROUGH. THE GLOBAL GEM IS AN OUTLIER AND WILL USE A GFS/EC SOLUTION. THIS BRINGS THE BEST CHANCES OF LIGHT SNOW ACCUMULATIONS MAINLY ALONG AND WEST OF THE HIGHWAY 83 CORRIDOR. SNOW GROWTH ZONE BECOMES RATHER DEEP BY 00 UTC SUNDAY BUT OMEGA WITHIN THE ZONE IS LIMITED. BUT WITH SNOW RATIOS INCREASING AS THE COLD AIR FILTERS IN...THINK ONE OR TWO INCH ACCUMULATIONS ARE POSSIBLE SATURDAY THROUGH SATURDAY NIGHT OVER THE WESTERN HALF OF NORTH DAKOTA. A NORTHEAST SURFACE FLOW OF 10 TO 20 MPH COULD YIELD SOME REDUCED VISIBILITIES IN FALLING SNOW...BUT SIGNIFICANT BLOWING AND DRIFTING IS NOT EXPECTED AT THIS TIME. THE REMAINDER OF THE FORECAST PERIOD BRINGS BELOW AVERAGE TEMPERATURES AND ONLY MINIMAL PRECIPITATION CHANCES AHEAD OF EACH REINFORCING SHOT OF COLD AIR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 630 AM CST WED JAN 28 2015 WIDESPREAD VLIFR CIGS WILL IMPACT ALL TERMINALS BY EARLY TODAY AS LOW STRATUS AND FOG EXPAND SOUTH AND WEST ACROSS NORTH DAKOTA. LOW STRATUS WILL THEN HOLD ON THROUGH WEDNESDAY NIGHT BUT WILL LIFT TO LIFR/IFR MOST AREAS. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR NDZ002>005-010>013- 021>023-025-036-037. && $$ UPDATE...TWH SHORT TERM...NH LONG TERM...TWH AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
546 AM CST WED JAN 28 2015 .UPDATE... ISSUED AT 546 AM CST WED JAN 28 2015 BASED ON TRENDS VIA OBSERVATIONS AND SATELLITE IMAGERY...WILL LEAN ON HRRR GUIDANCE (WHICH IS DOING VERY WELL) AND EXPAND FOG WORDING WEST AND SOUTH AND WILL ALSO EXPAND THE DENSE FOG ADVISORY FARTHER WEST. ALSO EXTENDED TILL 18Z FOR HEADLINE CUTOFF. UPDATE ISSUED AT 344 AM CST WED JAN 28 2015 WILL GO WITH A DENSE FOG ADVISORY EAST. OBSERVATIONS NOT GETTING ANY BETTER AND AREA WEB CAMS SHOWING WORSE VISIBILITIES NOW. UPDATED PRODUCTS OUT SOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CST WED JAN 28 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE COOLER TEMPERATURES...BREEZY CONDITIONS...AND CHANCES FOR LIGHT SNOW TODAY AND TONIGHT. CURRENTLY...ZONAL FLOW ALOFT WITH THE UPPER LEVEL RIDGE FLATTENING ACROSS THE GREAT PLAINS IN RESPONSE TO SOUTHERN AND NORTHERN STREAM S/WV`S CROSSING THE ROCKIES. SURFACE LOW PRESSURE ASSOCIATED WITH THE SOUTHERN STREAM WAVE MOVING SOUTHEAST ACROSS SOUTHWEST NORTH DAKOTA INTO CENTRAL SOUTH DAKOTA. SOUTH/SOUTHEASTERLY RETURN FLOW AHEAD OF THE LOW HAS MAINTAINED LOW STRATUS AND/OR FOG ACROSS EASTERN NORTH DAKOTA SINCE YESTERDAY EVENING. LARGE STRATUS FIELD WRAPS BACK WESTWARD ACROSS SOUTH CENTRAL CANADA WITH THE SOUTHERN EDGE OF THE STRATUS ALONG TO SLIGHTLY NORTH OF THE INTERNATIONAL BORDER. VISIBILITIES CONTINUE TO FLUCTUATE ACROSS MY EAST...AND WILL HANDLE THE PATCHY DENSE FOG WITH THE CURRENT SPECIAL WEATHER STATEMENT. AS THE SURFACE LOW CONTINUES SOUTHEAST TODAY...SURFACE WINDS BECOME MORE NORTHWESTERLY AND INCREASE THROUGH THE MORNING INTO THE AFTERNOON BEHIND A STRONG SFC COLD FRONT. BUFKIT ANALYSIS BRINGS 35 TO NEAR 40KTS WITHIN THE TOP OF THE MIXED LAYER TO MOST SITES...SO WHILE BREEZY...SUB-ADVISORY MAGNITUDES. THUS NO HEADLINES WITH THIS FORECAST ISSUANCE. STRATUS TO OUR NORTH SURGES SOUTH ALONG WITH CAA WITH MOST OF REGION CLOUDED OVER BY EARLY TO MID AFTERNOON. CLOUD COVER AND BREEZY CONDITIONS WILL THEN CONTINUE INTO WEDNESDAY NIGHT. POST FRONTAL SNOW SHOWERS DEVELOP LATER THIS MORNING NORTH THEN SOUTHWARD THIS AFTERNOON CONTINUING TONIGHT. KEPT POPS AT SLIGHT CHANCE FOR NOW...BUT MAY NEED TO BE INCREASED. FOR TEMPERATURES...DESPITE CAA AND CLOUD COVER...THE INCREASED MIXING WITH THE BREEZY NORTHWEST WIND WILL ACTUALLY KEEP TEMPERATURES FROM BOTTOMING OUT TOO MUCH TODAY. DAYTIME HIGHS WILL BE COOLER THAN TUESDAY...RANGING FROM THE LOW 30S NORTH TO MID/UPPER 40S SOUTHWEST. SO ABOUT 5-15 DEGREES COOLER. CLOUD COVER AND CONTINUED MIXING TONIGHT SHOULD ALSO KEEP LOWS FROM DROPPING TOO MUCH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 315 AM CST WED JAN 28 2015 CHANCES FOR SNOW SATURDAY AND COOLER TEMPERATURES THROUGH THE WEEKEND AND INTO NEXT WEEK WILL HIGHLIGHT THE LONG TERM. AN UPPER LEVEL TROUGH MOVING SOUTHEAST FROM ALBERTA LATE FRIDAY INTO EARLY SATURDAY MORNING WILL BRING A CHANCE OF SNOW THROUGH SATURDAY NIGHT...ALONG WITH COLDER TEMPERATURES. THERE IS GOOD AGREEMENT BETWEEN THE GFS/ECMWF IN THE OVERALL TIMING/LOCATION OF THE UPPER LEVEL TROUGH. THE GLOBAL GEM IS AN OUTLIER AND WILL USE A GFS/EC SOLUTION. THIS BRINGS THE BEST CHANCES OF LIGHT SNOW ACCUMULATIONS MAINLY ALONG AND WEST OF THE HIGHWAY 83 CORRIDOR. SNOW GROWTH ZONE BECOMES RATHER DEEP BY 00 UTC SUNDAY BUT OMEGA WITHIN THE ZONE IS LIMITED. BUT WITH SNOW RATIOS INCREASING AS THE COLD AIR FILTERS IN...THINK ONE OR TWO INCH ACCUMULATIONS ARE POSSIBLE SATURDAY THROUGH SATURDAY NIGHT OVER THE WESTERN HALF OF NORTH DAKOTA. A NORTHEAST SURFACE FLOW OF 10 TO 20 MPH COULD YIELD SOME REDUCED VISIBILITIES IN FALLING SNOW...BUT SIGNIFICANT BLOWING AND DRIFTING IS NOT EXPECTED AT THIS TIME. THE REMAINDER OF THE FORECAST PERIOD BRINGS BELOW AVERAGE TEMPERATURES AND ONLY MINIMAL PRECIPITATION CHANCES AHEAD OF EACH REINFORCING SHOT OF COLD AIR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 546 AM CST WED JAN 28 2015 WIDESPREAD VLIFR CIGS WILL IMPACT ALL TERMINALS BY EARLY TODAY AS LOW STRATUS AND FOG EXPAND SOUTH AND WEST ACROSS NORTH DAKOTA. LOW STRATUS WILL THEN HOLD ON THROUGH WEDNESDAY NIGHT BUT WILL LIFT TO LIFR/IFR MOST AREAS. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR NDZ002>005-010>013- 021>023-025-036-037. && $$ UPDATE...NH SHORT TERM...NH LONG TERM...TWH AVIATION...NH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
550 AM CST WED JAN 28 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 316 AM CST WED JAN 28 2015 TRICKY TEMPERATURE FORECAST TODAY...WHICH WILL BE LARGELY DEPENDENT ON THE EXTENT OF CLOUD COVERAGE. VERY MILD 925 MB TEMPERATURES ABOVE ZERO AND SOUTHERLY WINDS AT THE SURFACE WILL TAP INTO SOME CONTINUED SEASONABLY WARM TEMPERATURES. THE QUESTION IS HOW MUCH CLOUD COVER WILL IMPACT WARMING TODAY. THE MOST RECENT HRRR HAS A GOOD HANDLE ON CLOUDS EARLY THIS MORNING...WHICH WILL SHIFT EASTWARD INTO THE MIDDAY HOURS. THINK THE THE NORTHEASTERN HALF OF THE FORECAST AREA...FROM EAST CENTRAL SD INTO SOUTHWEST MN AND THE IOWA GREAT LAKES ARE WILL HOLD ONTO MOSTLY CLOUDY SKIES THE BULK OF THE DAY. KEPT TEMPERATURES ON THE CONSERVATIVE SIDE OF GUIDANCE IN THIS AREA. IF CLOUDS LOOK LESS ABUNDANT...COULD SEE READINGS WARM ABOVE FORECAST HIGHS. ELSEWHERE...MOSTLY SUNNY TO PARTLY CLOUDY SKIES THROUGH MID AFTERNOON WILL GIVE WAY TO CLOUDS WITH THE ANTICIPATED FRONTAL PASSAGE LATE AFTERNOON. SOUTH CENTRAL SD INTO THE MISSOURI VALLEY WILL HAVE THE BEST POTENTIAL TO WARM INTO THE LOW TO MID 50S. WITH THE FRONT TRACKING THROUGH THE AREA MID AFTERNOON INTO THIS EVENING...CLOUDS WILL ROLL BACK INTO THE REGION. NORTHWEST WINDS EXPECTED TO BECOME QUITE WINDY BEHIND THE FRONT WITH 40 TO 50 KT WINDS JUST OFF THE SURFACE. AT THE SURFACE...WINDS WILL LIKELY BE NEAR ADVISORY LEVEL...ESPECIALLY WITH GUSTS AROUND 40 OR 45 MPH. GIVEN THAT THE STRONGEST WINDS ARE EXPECTED IN THE EARLY MORNING HOURS AND ARE MARGINAL FOR AN ADVISORY...WILL HOLD OFF ISSUING ANY HEADLINES FOR NOW. WITH LOW LEVEL STRATUS BLANKETING THE AREA OVERNIGHT...A FAST MOVING SHORTWAVE DROPS ACROSS SOUTHWEST MINNESOTA LATE EVENING INTO THE EARLY MORNING HOURS. NOT MUCH MOISTURE IN PLACE...AND WHILE THE LOW STRATUS DOES THICKEN...THE CLOUD MASS REMAINS LARGELY OUTSIDE THE SNOW GROWTH ZONE. COULD SEE A FEW SNOW ISOLATED SHOWERS DEVELOP MAINLY IN OUR MN COUNTIES...WITH SOME PATCH DRIZZLE ALSO POSSIBLE. SURFACE TEMPERATURES WILL BE NEAR OR JUST ABOVE FREEZING IN THIS AREA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 316 AM CST WED JAN 28 2015 THE SHORTWAVE EXITS THE AREA ON THURSDAY WITH SURFACE HIGH PRESSURE BUILDING INTO THE REGION. IT WILL BE BREEZY WITH A TIGHT GRADIENT ACROSS THE AREA AND GOOD MIXING IN A COLD AIR ADVECTION REGIME. IN RESPONSE TO THE COLDER AIR FILTERING INTO THE REGION BEHIND THE EXITING SHORTWAVE...HIGH TEMPERATURES WILL BE A GOOD 10 TO 15 DEGREES COOLER THAN TODAY...TOPPING OUT IN THE UPPER 20S FROM EAST CENTRAL SD THROUGH SOUTHWESTERN MN...TO UPPER 30S THROUGH THE MO RIVER CORRIDOR. WINDS WILL DIE OFF ON THURSDAY NIGHT...LEADING TO A COLD NIGHT WITH LOWS IN THE LOWER/MID TEENS THROUGH THE EASTERN TWO THIRDS OF THE CWA. TO THE WEST...IT WILL NOT BE QUITE AS COLD WITH AN ENSUING SOUTHEASTERLY FLOW BEHIND THE EXITING HIGH PRESSURE...WITH LOWS GENERALLY LOWER 20S. FRIDAY WILL SEE WARMING WITH A STRENGTHENING SOUTHERLY FLOW ON THE BACKSIDE OF THE HIGH. HIGH TEMPERATURES WILL RUN LOWER 30S NORTHEAST TO AS WARM AS THE MID 40S THROUGH SOUTH CENTRAL SD. ON SATURDAY NORTHERN STREAM UPPER LEVEL ENERGY DROPS OUT OF WESTERN CANADA AND SLIDES SOUTHWARD AS SOUTHERN STREAM ENERGY LIFTS TO THE NORTH...CONVERGING OVER THE CENTRAL PLAINS. STILL SOME MODEL DIFFERENCES ON HOW THIS SCENARIO EVOLVES...BUT DOES POTENTIALLY BRING PRECIPITATION TO AT LEAST OUR SOUTHERN AND EASTERN CWA FOR LATER ON SATURDAY AFTERNOON AND SATURDAY NIGHT. PRECIPITATION TYPE LOOKS TO BE MAINLY IN THE FORM OF SNOW...WITH COOLING THERMAL PROFILES AS LOW PRESSURE OVER THE JAMES BAY BEGINS TO DRIVE COLDER AIR SOUTHWARD. AT THIS POINT SNOWFALL AMOUNTS LOOK TO BE IN THE RANGE OF 2 TO 3 INCHES IN OUR SOUTHEAST...THOUGH WILL HAVE TO WATCH THE TRACK OF THIS SYSTEM FOR GREATER SNOWFALL AMOUNTS IF IT TRENDS FARTHER TO THE NORTH. IT STILL WONT BE UNREASONABLY COLD ON SATURDAY WITH HIGHS MAINLY IN THE 30S...BUT BY SATURDAY NIGHT AND SUNDAY MUCH COLDER AIR WILL HAVE SETTLED INTO THE REGION WITH HIGHS ON SUNDAY MOSTLY IN THE TEENS. THE COLD AIR THEN LOOKS TO LINGER THROUGH NEXT MONDAY...WITH SOME MODERATION POSSIBLE BY TUESDAY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 540 AM CST WED JAN 28 2015 MVFR/IFR CEILINGS ARE TRACKING ALONG OUR FAR EASTERN COUNTIES EARLY THIS MORNING. THIS STRATUS IS NOT EXPECTED TO EXPAND MUCH FURTHER WEST THIS MORNING...HOWEVER A FAST MOVING FRONT WILL TRACK WEST TO EAST THROUGH THE FORECAST AREA 18Z THROUGH 00Z THIS AFTERNOON/EVENING AND USHER IN ADDITION LOW LEVEL CLOUDS BEHIND IT. STRONG NORTHWEST WINDS BEHIND THE FRONT WILL AVERAGE 20 TO 25 KT WITH FREQUENT GUSTS 30+ KT IN THE EVENING AND OVERNIGHT. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM... LONG TERM...JM AVIATION...
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1038 AM MST WED JAN 28 2015 .UPDATE... ISSUED AT 1033 AM MST WED JAN 28 2015 AN UPPER DISTURBANCE OVER WY AND EVIDENT ON SATELLITE WATER VAPOR IMAGES IS FORECAST BY SHORT-RANGE MODELS TO CLIP NW CO TODAY. THIS AND TRAILING NW FLOW WILL KEEP SOME LIGHT SNOW ACROSS THE NRN CO MTNS. A SPOTTER IN CORTEZ REPORTED SOME CUMULUS BUILDING TO THE NORTHEAST AND INDICATIVE OF SOME INSTABILITY ALOFT BUT THINK THE AIRMASS TOO DRY FOR ANY SIGNIFICANT THREAT OF SHOWERS FOR THE SAN JUANS. TRIMMED BACK POPS ACROSS THE GRAND MESA AND WEST ELKS TODAY PER CURRENT WEBCAM OBS AND LATEST AVAILABLE HRRR GUIDANCE. OTHERWISE...THE CURRENT FORECAST LOOKS ON TRACK. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 447 AM MST WED JAN 28 2015 THE LOW PRESSURE DISTURBANCE THAT MOVED NORTHWARD THROUGH NV YESTERDAY HAS BEEN PICKED UP BY THE WESTERLY FLOW OVER THE NORTHERN TIER STATES...AND HAS MOVED ACROSS SOUTHERN ID AND INTO FAR SOUTHWEST WY EARLY THIS MORNING. THIS DISTURBANCE WILL CONTINUE TO BRUSH OUR NORTHERN ZONES THROUGH THE NEXT FEW HOURS...WITH A NORTHWEST FLOW DEVELOPING BY LATE MORNING. RADAR ECHOES EARLY THIS MORNING INDICATE SOME LIGHT SHOWER ACTIVITY OVER THE COLORADO MOUNTAINS...WITH A FEW SHOWERS OVER THE NORTHERN CO VALLEYS. AS THE TROUGH AXIS PASSES LATER THIS MORNING A NORTHWEST FLOW WILL DEVELOP WHICH WILL COMBINE WITH THE STILL MOIST AIR MASS TO KEEP AREAS OF PRECIPITATION OVER THE FAVORED NORTHERN MOUNTAINS...ESPECIALLY ALONG THE NORTHERN DIVIDE. EARLY MORNING TEMPERATURES HAVE REMAINED MILD SO RAIN OR MIXED PRECIPITATION WILL BE POSSIBLE IN THE MIDDLE YAMPA RIVER BASIN FROM AROUND MILNER WEST. WE DO GET SOME WEAK COOLING IN THE NORTHWEST FLOW...BUT DAYTIME HIGHS WILL REMAIN ABOVE NORMAL... BUT SLIGHTLY COOLER THAN TUESDAY`S. MID-HIGH LEVEL MOISTURE WILL REMAIN OVER THE REGION THROUGH THURSDAY AS THE RIDGE TEMPORARILY REBOUNDS ALONG THE CENTRAL ROCKIES. DEEPER MOISTURE WILL BEGIN TO MOVE INTO THE DESERT SOUTHWEST AHEAD OF ANOTHER LOW PRESSURE SYSTEM COMING ONSHORE ALONG THE SOUTHWEST COAST. BUT MORE ABOUT THAT IN THE LONG TERM DISCUSSION. THE CLOUDY SKIES WILL KEEP TEMPERATURES SIMILAR TO A COUPLE DEGREES COOLER THAN TODAY`S. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 447 AM MST WED JAN 28 2015 MOISTURE SURGE FROM THE SOUTH COMBINED WITH ISENTROPIC UPGLIDE RESULTS IN EXPANDING CLOUD/PRECIPITATION SHIELD THURSDAY NIGHT. A DEVELOPING CLOSED UPPER LOW OVER THE SRN COLORADO RIVER BASIN WILL KEEP THE AIR MASS MOIST THROUGH SATURDAY. MOST AREAS SOUTH OF HIGHWAY 40 (VERNAL TO STEAMBOAT SPRINGS) STAND A VERY GOOD CHANCE OF OBSERVING SOME PCPN...BUT DROP OFF SIGNIFICANTLY NORTH OF THIS HIGHWAY. THE FORECAST CHALLENGE IS HOW MUCH QPF FALLS AND THE PCPN TYPE (ESPECIALLY THE HIGHER SWRN COLORADO VALLEYS). WHILE SOME MODEL SPREAD STILL EXISTS REGARDING THE EVOLUTION ON THE DEVELOPING CLOSED LOW CIRCULATION...THE NAM...GFS AND ECMWF SHOW SIMILAR TRENDS. THE BEST MOISTURE TRANSPORT STAYS SOUTH AND EAST OF THE FORECAST AREA...TARGETING THE SOUTHERN PLAINS. SOME CYCLOGENETICAL FORCING DOES EXIST...BUT THE BULLSEYE STAYS SOUTH OF THE FORECAST AREA. THE GFS HINTS OF A SURFACE LOW NEAR DURANGO BY SATURDAY MORNING...BUT NO OTHER MODEL SHOWS THIS AND THEREFORE NOT CONFIDENT IN THIS SOLUTION. GIVEN THESE ASSESSMENTS...PATTERN FAVORS PCPN AND HIGH POP VALUES FOR THE SRN HALF IS WARRANTED LATE THURSDAY NIGHT INTO SATURDAY MORNING. WITH REGARD TO SNOW AMOUNTS...QPF WITH SNOW RATIOS ON THE ORDER OF 8:1 TO 10:1 MAY ONLY RESULT IN 4 TO 8 INCHES WITH LOCALIZED AREAS REACHING 12 INCHES. WILL ALLOW THE NEXT SHIFT TO MAKE ANOTHER ASSESSMENT BUT ELECTED NOT TO ISSUE A WINTER STORM WATCH AT THIS TIME FOR THE SRN MOUNTAINS. FOR THE SRN VALLEYS BETWEEN 6000 TO 8000 FEET...PCPN TYPE MAY DEPEND ON THE TIME OF DAY. RAIN IN THE AFTERNOON...BUT TRANSITIONING TO SNOW OR RAIN/SNOW MIXTURE DURING THE OVERNIGHT HOURS. SATURDAY AFTERNOON INTO SUNDAY...NRN STREAM DIVES TOWARD COLORADO AND SHUNTS MOISTURE SOUTHWARD. THE CLOSED LOW CIRCULATION BEGINS TO WEAKEN AND MOVE FARTHER SOUTH. THE PROGRESSIVE NRN STREAM SHORT WAVE BRIEFLY ENHANCES OROGRAPHIC SNOWFALL AND LOWERS THE SNOW LEVEL...BUT DRIER AIR SPREADS ACROSS THE ENTIRE FORECAST AREA OVERNIGHT ON SATURDAY INTO SUNDAY. WITH THE AMPLIFIED RIDGE AXIS GONE...PACIFIC ENERGY CONTINUES TO MOVE INTO THE PACIFIC NORTHWEST ON MONDAY AND TUESDAY. CYCLONIC NORTHWEST FLOW ALLOW SHORT WAVE ENERGY TO MOVE ACROSS THE CENTRAL ROCKIES. THE LONG WAVE PATTERN MAY BE IN STATE OF FLUX HERE AND NOT CLEAR HOW THESE PACIFIC WAVES WILL IMPACT THE NRN MOUNTAINS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1033 AM MST WED JAN 28 2015 WEAK DISTURBANCE WILL CLIP NW CO TODAY FOLLOWED BY NW FLOW FOR SOME MTN OBSCURATIONS IN - SN FROM KCCU TO K3MW THIS AFTERNOON. ISOLD TO SCT -SHSN/-SHRA MAY BRIEFLY PRODUCE MVFR CIGS AT KASE UNTIL 00Z...SO WILL CONTINUE TO CARRY VCSH THERE AS WELL AS AT KEGE. OTHERWISE...VFR SHOULD BE THE PREVAILING CONDITIONS AT ALL TAF SITES THROUGH THU MORNING AS HIGH CLOUDS INVADE FROM THE SOUTHWEST. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...JAD SHORT TERM...EH LONG TERM...PF AVIATION...JAD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
212 PM CST WED JAN 28 2015 .SHORT TERM... 345 AM CST TODAY THROUGH FRIDAY NIGHT... MAIN FORECAST CONCERNS IN THE SHORT TERM ARE CLOUD AND TEMP TRENDS TODAY AND TONIGHT...AND TIMING...COVERAGE AND TYPE OF PRECIPITATION TONIGHT AND THURSDAY AS LOW PRESSURE ORGANIZING OVER THE PLAINS MOVES EAST. RELATIVELY QUIET WEATHER THIS MORNING AS SURFACE HIGH PRESSURE DRIFTS SLOWLY EAST OF THE AREA. SUBSIDENCE ASSOCIATED WITH HEIGHT RISES ALOFT HAS LED TO A STRONG INVERSION AT AROUND 900 HPA HOWEVER PER DVN 00Z SOUNDING...WHICH HAS TRAPPED LOW CLOUDS ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA OVERNIGHT. CLOUDS WERE SLOWLY ERODING FROM THE SOUTHEAST THANKS TO 950-900 HPA WINDS GRADUALLY VEERING TO THE SOUTHEAST AND SOUTH...AND LOWERING SUBSIDENCE INVERSION. RAP GUIDANCE INDICATES SOUTH WINDS WILL INCREASE THIS MORNING AND SHOULD CONTINUE TO LIFT THESE LOWER CLOUDS NORTH TOWARD THE WI BORDER...THOUGH OVERALL NORTH CENTRAL ILLINOIS IS LIKELY TO BE CLOUDIER THAN AREAS SOUTH AND EAST TODAY EVEN AS MID AND HIGH CLOUDS BEGIN TO INCREASE AS WARM ADVECTION DEVELOPS ALOFT. SURFACE LOW PRESSURE IS ALREADY TAKING SHAPE ACROSS THE PLAINS TO OUR WEST THIS MORNING...IN RESPONSE TO A SHORT WAVE TROUGH EMERGING FROM THE CENTRAL/NORTHERN ROCKIES. SURFACE PRESSURE FALLS AHEAD OF THIS DEVELOPING LOW WILL LEAD TO INCREASING SOUTH-SOUTHEAST WINDS NEAR 25 MPH THIS AFTERNOON. DESPITE SOUTHERLY FLOW...LOW LEVEL PARCEL TRAJECTORIES WILL BE LARGELY FROM INDIANA/OHIO WHERE STRONG COOLING HAS OCCURRED NEAR THE SURFACE HIGH THIS MORNING. COMBINED WITH SOME MID/HIGH CLOUD COVER THIS MAY MAKE FOR HIGH TEMPERATURES COMING LATER IN THE DAY WHEN LOW LEVEL WINDS VEER MORE SOUTHERLY AND TAP MILDER AIR CURRENTLY ACROSS THE MISSOURI VALLEY. STRONG SOUTH FLOW WILL CONTINUE TONIGHT AHEAD OF THE APPROACHING SURFACE LOW...ALLOWING TEMPS TO STAY ABOVE FREEZING IN MOST AREAS. GUIDANCE IN GOOD AGREEMENT IN DEVELOPING SOME LIGHT SPOTTY PRECIPITATION ACROSS THE AREA LATE THIS EVENING...EXPANDING OVERNIGHT ESPECIALLY ACROSS NORTHERN/NORTHEASTERN PARTS OF THE FORECAST AREA. FORECAST SOUNDINGS INDICATE WARM LAYER TEMPS ALOFT IN THE +5C RANGE OR BETTER...WITH SATURATION INITIALLY OCCURRING BELOW 700 HPA AND SUPPORTING LIGHT RAIN. WITH BREEZY SOUTH SURFACE WINDS KEEPING TEMPS ABOVE MAINLY ABOVE FREEZING...PRECIPITATION TYPE IS EXPECTED TO REMAIN LIQUID IN MOST LOCATIONS. LOW PROBABILITY DOES EXIST FOR LIGHT FREEZING RAIN ESPECIALLY ACROSS FAR NORTH/NORTHEAST IL...BUT AT THIS TIME FEEL IT IS FAIRLY UNLIKELY. THE SURFACE LOW...AND A PAIR OF UN-PHASED SHORT WAVES....MOVE ACROSS THE CWA DURING THE MORNING AND RESULT IN WINDS SHIFTING TO THE NORTHWEST. THIS BRINGS COLDER AIR INTO THE REGION WITH COLLAPSING THICKNESS FIELDS SUPPORTING LINGERING PRECIPITATION CHANGING OVER FROM LIGHT RAIN TO A BRIEF RAIN/SLEET/SNOW MIX BEFORE ENDING FROM WEST-EAST. MOST PRECIPITATION SHOULD END BY NOON WEST OF ABOUT THE IL/IN STATE LINE...AND SHORTLY AFTER ACROSS NORTHWEST INDIANA. HOWEVER...GUSTY NORTH-NORTHWEST WINDS AND COLDER AIR SPREADING ACROSS LAKE MICHIGAN WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS ACROSS PARTS OF EASTERN LAKE AND PORTER COUNTIES ESPECIALLY THURSDAY EVENING INTO EARLY FRIDAY MORNING. THE REMAINDER OF THE AREA WILL JUST BE BLUSTERY AND COLDER...WITH NORTH-NORTHWEST WINDS GUSTING ABOVE 30 MPH AT TIMES THURSDAY BEFORE SLOWLY DIMINISHING THURSDAY NIGHT. AFTER MORNING HIGHS IN THE MID-UPPER 30S OR EVEN NEAR 40 IN SOME SPOTS...THURSDAY NIGHT LOOKS TO BE COLD WITH LOWS IN THE TEENS TO LOW 20S AND SINGLE DIGIT WIND CHILLS. SURFACE HIGH PRESSURE SPREADS INTO THE AREA AGAIN ON FRIDAY...WITH TEMPERATURES STRUGGLING INTO THE MID-UPPER 20S BUT WITH MUCH LIGHTER WINDS. LAKE SNOW SHOWERS WILL DIMINISH ACROSS NORTHWEST INDIANA AS INVERSION HEIGHTS LOWER AND LOW LEVEL WINDS DIMINISH...WITH SUNSHINE ELSEWHERE. RATZER && .LONG TERM... 345 AM CST SATURDAY THROUGH TUESDAY... THE MAIN FOCUS IN THE EXTENDED PERIOD IS ON A STORM SYSTEM WHICH LOOKS TO LIFT THROUGH THE OHIO VALLEY LATE SATURDAY NIGHT THROUGH SUNDAY. ECMWF/GFS ARE IN RELATIVELY GOOD AGREEMENT IN TAKING SURFACE LOW TRACK ALONG THE OHIO RIVER...THOUGH GFS IS A LITTLE SLOWER AND GEFS ENSEMBLE MEMBERS STILL SHOW QUITE A BIT OF SPREAD IN THEIR SOLUTIONS AT THE SURFACE. GEM ALSO SLOWER AND A BIT FARTHER SOUTH THAN THE OTHER GLOBAL MODELS. DEPENDING UPON HOW THIS SYSTEM EVENTUALLY TRACKS...IT COULD BE A SNOW PRODUCER FOR ALL OR PART OF THE CWA...AS IT TAPS GULF MOISTURE DEFORMATION BAND WOULD LIKELY CROSS CENTRAL IL/IN. GLOBAL MODELS ALSO INDICATE A STRONG SURGE OF ARCTIC AIR IN THE WAKE OF THIS SYSTEM...WITH SIGNIFICANTLY COLDER WEATHER I.E. LOWS +/- SINGLE DIGITS AND HIGHS PERHAPS ONLY IN THE TEENS BY MONDAY/TUESDAY. RATZER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * GUSTY SOUTH-SOUTHEAST SURFACE WINDS THIS AFTERNOON...POSSIBLY STRENGTHENING INTO EVENING. * SCATTERED LIGHT RAIN SHOWERS LIKELY AND MVFR CIGS DEVELOPING OVERNIGHT...AND THE POSSIBILITY OF A BRIEF MIX WITH SNOW AND IFR BEFORE ENDING THURSDAY MORNING. * SOUTH-SOUTHWEST WINDS AT 2000 FT OF AT LEAST 40-45 KT THIS EVENING INTO OVERNIGHT THAT MAY CREATE LOW-LEVEL WIND SHEAR. * NORTHWEST WINDS GUSTING TO AROUND 30 KT DURING THE DAY THURSDAY. KMD //DISCUSSION...UPDATED 18Z... QUITE A FEW AVIATION CONCERNS FOR THIS TAF CYCLE. THE FIRST CENTERS AROUND WINDS. SE WINDS WILL GRADUALLY RAMP UP THIS AFTERNOON AND EVENING WITH SUSTAINED WINDS HOLDING IN THE MID TEENS AND GUSTS INTO 22-24 KT RANGE AHEAD OF LOW PRESSURE MOVING EAST THROUGH THE PLAINS. THE LOW MOVES THROUGH LATE TONIGHT WITH A TRAILING COLD FRONT INTO TOMORROW MORNING. AFTER A PERIOD OF LIGHTER WINDS...NW WINDS RAMP UP QUICKLY MID MORNING THROUGH THE AFTERNOON. NAM/GFS FORECAST SOUNDINGS SHOW GOOD MIXING THAT WILL SUPPORT 30 KT OR SO GUSTS THROUGH THE AFTERNOON. AT THIS POINT LLWS HAS NOT BEEN INTRODUCED AS WINDS AT 2000 FT WILL REACH 40-45 KT WHICH IS ON THE THRESHOLD...BUT WITH THE CONTINUED GUSTINESS IT IS MARGINAL AT THIS POINT. DURING PERIODS OF LESS FREQUENT GUSTS THERE COULD BE SOME LLWS. OTHER CONCERNS REVOLVE AROUND PRECIPITATION EVOLUTION AND TYPE THROUGH EARLY THURSDAY. SEVERAL MODELS SHOW SOME DECENT LIFT IN THE WARM ADVECTIVE REGIME THIS EVENING. IN SPITE OF THIS...GUIDANCE IS MIXED AS TO HOW MUCH MOISTURE THERE WILL ACTUALLY BE TO SUPPORT PRECIPITATION DURING THIS INITIAL TIME FRAME. IF PRECIP WERE TO DEVELOP IN THE 4Z-8Z TIME FRAME...SURFACE TEMPERATURES COULD SUPPORT FZRA. HAVE ONLY GONE WITH A VCSH GIVEN THE LACK OF MOISTURE ON SOME GUIDANCE...BUT WILL BE A PERIOD TO WATCH. BETTER CHANCES OF PRECIPITATION COME WITH THE COLD FRONT LATE TONIGHT INTO EARLY THURSDAY. PRECIP LOOKS TO BE A RAIN OR DRIZZLE BEFORE TAPERING TO A RAIN SNOW MIX. SURFACE TEMPS HOLD AT OR ABOVE 32 FOR MOST OF THE PRECIP THUS LITTLE TO NO ACCUMULATION IS EXPECTED. KMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH IN WIND DIRECTION AND SPEED THROUGH THIS EVENING...INCLUDING THE WIND DIRECTION REMAINING SLIGHTLY EAST OF SOUTH. * MEDIUM IN PRECIPITATION OCCURRING AT THE AIRFIELD LATER TONIGHT AND EARLY THURSDAY MORNING. MEDIUM ON PRECIPITATION TYPE. * MEDIUM THAT LLWS WILL REMAIN MARGINAL THROUGH THE EVENING. * HIGH IN MVFR CIGS LATE TONIGHT INTO THURSDAY MORNING THOUGH MEDIUM ON TIMING. MEDIUM IN ANY IFR OCCURRING. KMD //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...MAINLY VFR. NORTH-NORTHWEST WINDS. FRIDAY...VFR. NORTHWEST WINDS. SATURDAY...CHANCE OF SNOW AND IFR DURING THE NIGHT. SOUTHWEST WINDS. SUNDAY...SNOW AND IFR LIKELY. NORTHEAST WINDS. MONDAY...CHANCE OF SNOW WITH MVFR LIKELY. IFR POSSIBLE. NORTHWEST WINDS. TUESDAY...CHANCE OF SNOW DURING THE NIGHT. SOUTHWEST WINDS. MTF && .MARINE... 211 PM CST I HAVE UPGRADED THE GALE WATCH TO A WARNING FOR THURSDAY AFTERNOON AND NIGHT. AN AREA OF LOW PRESSURE APPROACHING THE LAKES REGION FROM THE PLAINS WILL PRODUCE A PERIOD OF STRONG SOUTHERLY WINDS AROUND 30 KT TONIGHT...THEN A PERIOD OF NORTHERLY GALE FORCE WINDS THURSDAY AFTERNOON AND NIGHT AS MUCH COLD AIR SPILLS IN OVER THE LAKES IN THE WAKE OF THIS LOW. I HAVE INCLUDED MY ILLINOIS NEAR SHORES IN THIS GALE WARNING AS IT APPEARS THE OFF SHORE COMPONENT OF THE WIND WILL BE STRONG ENOUGH TO SUPPORT SOME LOW END GALES. SURFACE HIGH PRESSURE WILL GRADUALLY BUILD EASTWARD ACROSS THE PLAINS AND UPPER MIDWEST LATER THURSDAY AND THURSDAY NIGHT...AND THIS SHOULD ALLOW FOR SOME STRONGER WINDS TO CONTINUE INTO EARLY FRIDAY...BEFORE DIMINISHING BY FRIDAY AFTERNOON. ANOTHER COLD FRONT LOOKS TO DROP ACROSS THE LAKES ON SUNDAY...AND A PERIOD OF STRONGER NORTHERLY WINDS (25 TO 30 KT) APPEAR LIKELY IN ITS WAKE AS A VERY COLD AIRMASS MOVES SOUTHWARD OVER THE LAKE. KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 4 AM THURSDAY. GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON THURSDAY TO 3 AM FRIDAY. && $$ 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
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
152 PM CST WED JAN 28 2015 .SHORT TERM... 345 AM CST TODAY THROUGH FRIDAY NIGHT... MAIN FORECAST CONCERNS IN THE SHORT TERM ARE CLOUD AND TEMP TRENDS TODAY AND TONIGHT...AND TIMING...COVERAGE AND TYPE OF PRECIPITATION TONIGHT AND THURSDAY AS LOW PRESSURE ORGANIZING OVER THE PLAINS MOVES EAST. RELATIVELY QUIET WEATHER THIS MORNING AS SURFACE HIGH PRESSURE DRIFTS SLOWLY EAST OF THE AREA. SUBSIDENCE ASSOCIATED WITH HEIGHT RISES ALOFT HAS LED TO A STRONG INVERSION AT AROUND 900 HPA HOWEVER PER DVN 00Z SOUNDING...WHICH HAS TRAPPED LOW CLOUDS ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA OVERNIGHT. CLOUDS WERE SLOWLY ERODING FROM THE SOUTHEAST THANKS TO 950-900 HPA WINDS GRADUALLY VEERING TO THE SOUTHEAST AND SOUTH...AND LOWERING SUBSIDENCE INVERSION. RAP GUIDANCE INDICATES SOUTH WINDS WILL INCREASE THIS MORNING AND SHOULD CONTINUE TO LIFT THESE LOWER CLOUDS NORTH TOWARD THE WI BORDER...THOUGH OVERALL NORTH CENTRAL ILLINOIS IS LIKELY TO BE CLOUDIER THAN AREAS SOUTH AND EAST TODAY EVEN AS MID AND HIGH CLOUDS BEGIN TO INCREASE AS WARM ADVECTION DEVELOPS ALOFT. SURFACE LOW PRESSURE IS ALREADY TAKING SHAPE ACROSS THE PLAINS TO OUR WEST THIS MORNING...IN RESPONSE TO A SHORT WAVE TROUGH EMERGING FROM THE CENTRAL/NORTHERN ROCKIES. SURFACE PRESSURE FALLS AHEAD OF THIS DEVELOPING LOW WILL LEAD TO INCREASING SOUTH-SOUTHEAST WINDS NEAR 25 MPH THIS AFTERNOON. DESPITE SOUTHERLY FLOW...LOW LEVEL PARCEL TRAJECTORIES WILL BE LARGELY FROM INDIANA/OHIO WHERE STRONG COOLING HAS OCCURRED NEAR THE SURFACE HIGH THIS MORNING. COMBINED WITH SOME MID/HIGH CLOUD COVER THIS MAY MAKE FOR HIGH TEMPERATURES COMING LATER IN THE DAY WHEN LOW LEVEL WINDS VEER MORE SOUTHERLY AND TAP MILDER AIR CURRENTLY ACROSS THE MISSOURI VALLEY. STRONG SOUTH FLOW WILL CONTINUE TONIGHT AHEAD OF THE APPROACHING SURFACE LOW...ALLOWING TEMPS TO STAY ABOVE FREEZING IN MOST AREAS. GUIDANCE IN GOOD AGREEMENT IN DEVELOPING SOME LIGHT SPOTTY PRECIPITATION ACROSS THE AREA LATE THIS EVENING...EXPANDING OVERNIGHT ESPECIALLY ACROSS NORTHERN/NORTHEASTERN PARTS OF THE FORECAST AREA. FORECAST SOUNDINGS INDICATE WARM LAYER TEMPS ALOFT IN THE +5C RANGE OR BETTER...WITH SATURATION INITIALLY OCCURRING BELOW 700 HPA AND SUPPORTING LIGHT RAIN. WITH BREEZY SOUTH SURFACE WINDS KEEPING TEMPS ABOVE MAINLY ABOVE FREEZING...PRECIPITATION TYPE IS EXPECTED TO REMAIN LIQUID IN MOST LOCATIONS. LOW PROBABILITY DOES EXIST FOR LIGHT FREEZING RAIN ESPECIALLY ACROSS FAR NORTH/NORTHEAST IL...BUT AT THIS TIME FEEL IT IS FAIRLY UNLIKELY. THE SURFACE LOW...AND A PAIR OF UN-PHASED SHORT WAVES....MOVE ACROSS THE CWA DURING THE MORNING AND RESULT IN WINDS SHIFTING TO THE NORTHWEST. THIS BRINGS COLDER AIR INTO THE REGION WITH COLLAPSING THICKNESS FIELDS SUPPORTING LINGERING PRECIPITATION CHANGING OVER FROM LIGHT RAIN TO A BRIEF RAIN/SLEET/SNOW MIX BEFORE ENDING FROM WEST-EAST. MOST PRECIPITATION SHOULD END BY NOON WEST OF ABOUT THE IL/IN STATE LINE...AND SHORTLY AFTER ACROSS NORTHWEST INDIANA. HOWEVER...GUSTY NORTH-NORTHWEST WINDS AND COLDER AIR SPREADING ACROSS LAKE MICHIGAN WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS ACROSS PARTS OF EASTERN LAKE AND PORTER COUNTIES ESPECIALLY THURSDAY EVENING INTO EARLY FRIDAY MORNING. THE REMAINDER OF THE AREA WILL JUST BE BLUSTERY AND COLDER...WITH NORTH-NORTHWEST WINDS GUSTING ABOVE 30 MPH AT TIMES THURSDAY BEFORE SLOWLY DIMINISHING THURSDAY NIGHT. AFTER MORNING HIGHS IN THE MID-UPPER 30S OR EVEN NEAR 40 IN SOME SPOTS...THURSDAY NIGHT LOOKS TO BE COLD WITH LOWS IN THE TEENS TO LOW 20S AND SINGLE DIGIT WIND CHILLS. SURFACE HIGH PRESSURE SPREADS INTO THE AREA AGAIN ON FRIDAY...WITH TEMPERATURES STRUGGLING INTO THE MID-UPPER 20S BUT WITH MUCH LIGHTER WINDS. LAKE SNOW SHOWERS WILL DIMINISH ACROSS NORTHWEST INDIANA AS INVERSION HEIGHTS LOWER AND LOW LEVEL WINDS DIMINISH...WITH SUNSHINE ELSEWHERE. RATZER && .LONG TERM... 345 AM CST SATURDAY THROUGH TUESDAY... THE MAIN FOCUS IN THE EXTENDED PERIOD IS ON A STORM SYSTEM WHICH LOOKS TO LIFT THROUGH THE OHIO VALLEY LATE SATURDAY NIGHT THROUGH SUNDAY. ECMWF/GFS ARE IN RELATIVELY GOOD AGREEMENT IN TAKING SURFACE LOW TRACK ALONG THE OHIO RIVER...THOUGH GFS IS A LITTLE SLOWER AND GEFS ENSEMBLE MEMBERS STILL SHOW QUITE A BIT OF SPREAD IN THEIR SOLUTIONS AT THE SURFACE. GEM ALSO SLOWER AND A BIT FARTHER SOUTH THAN THE OTHER GLOBAL MODELS. DEPENDING UPON HOW THIS SYSTEM EVENTUALLY TRACKS...IT COULD BE A SNOW PRODUCER FOR ALL OR PART OF THE CWA...AS IT TAPS GULF MOISTURE DEFORMATION BAND WOULD LIKELY CROSS CENTRAL IL/IN. GLOBAL MODELS ALSO INDICATE A STRONG SURGE OF ARCTIC AIR IN THE WAKE OF THIS SYSTEM...WITH SIGNIFICANTLY COLDER WEATHER I.E. LOWS +/- SINGLE DIGITS AND HIGHS PERHAPS ONLY IN THE TEENS BY MONDAY/TUESDAY. RATZER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * GUSTY SOUTH-SOUTHEAST SURFACE WINDS THIS AFTERNOON...POSSIBLY STRENGTHENING INTO EVENING. * SCATTERED LIGHT RAIN SHOWERS LIKELY AND MVFR CIGS DEVELOPING OVERNIGHT...AND THE POSSIBILITY OF A BRIEF MIX WITH SNOW AND IFR BEFORE ENDING THURSDAY MORNING. * SOUTH-SOUTHWEST WINDS AT 2000 FT OF AT LEAST 40-45 KT THIS EVENING INTO OVERNIGHT THAT MAY CREATE LOW-LEVEL WIND SHEAR. * NORTHWEST WINDS GUSTING TO AROUND 30 KT DURING THE DAY THURSDAY. KMD //DISCUSSION...UPDATED 18Z... QUITE A FEW AVIATION CONCERNS FOR THIS TAF CYCLE. THE FIRST CENTERS AROUND WINDS. SE WINDS WILL GRADUALLY RAMP UP THIS AFTERNOON AND EVENING WITH SUSTAINED WINDS HOLDING IN THE MID TEENS AND GUSTS INTO 22-24 KT RANGE AHEAD OF LOW PRESSURE MOVING EAST THROUGH THE PLAINS. THE LOW MOVES THROUGH LATE TONIGHT WITH A TRAILING COLD FRONT INTO TOMORROW MORNING. AFTER A PERIOD OF LIGHTER WINDS...NW WINDS RAMP UP QUICKLY MID MORNING THROUGH THE AFTERNOON. NAM/GFS FORECAST SOUNDINGS SHOW GOOD MIXING THAT WILL SUPPORT 30 KT OR SO GUSTS THROUGH THE AFTERNOON. AT THIS POINT LLWS HAS NOT BEEN INTRODUCED AS WINDS AT 2000 FT WILL REACH 40-45 KT WHICH IS ON THE THRESHOLD...BUT WITH THE CONTINUED GUSTINESS IT IS MARGINAL AT THIS POINT. DURING PERIODS OF LESS FREQUENT GUSTS THERE COULD BE SOME LLWS. OTHER CONCERNS REVOLVE AROUND PRECIPITATION EVOLUTION AND TYPE THROUGH EARLY THURSDAY. SEVERAL MODELS SHOW SOME DECENT LIFT IN THE WARM ADVECTIVE REGIME THIS EVENING. IN SPITE OF THIS...GUIDANCE IS MIXED AS TO HOW MUCH MOISTURE THERE WILL ACTUALLY BE TO SUPPORT PRECIPITATION DURING THIS INITIAL TIME FRAME. IF PRECIP WERE TO DEVELOP IN THE 4Z-8Z TIME FRAME...SURFACE TEMPERATURES COULD SUPPORT FZRA. HAVE ONLY GONE WITH A VCSH GIVEN THE LACK OF MOISTURE ON SOME GUIDANCE...BUT WILL BE A PERIOD TO WATCH. BETTER CHANCES OF PRECIPITATION COME WITH THE COLD FRONT LATE TONIGHT INTO EARLY THURSDAY. PRECIP LOOKS TO BE A RAIN OR DRIZZLE BEFORE TAPERING TO A RAIN SNOW MIX. SURFACE TEMPS HOLD AT OR ABOVE 32 FOR MOST OF THE PRECIP THUS LITTLE TO NO ACCUMULATION IS EXPECTED. KMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH IN WIND DIRECTION AND SPEED THROUGH THIS EVENING...INCLUDING THE WIND DIRECTION REMAINING SLIGHTLY EAST OF SOUTH. * MEDIUM IN PRECIPITATION OCCURRING AT THE AIRFIELD LATER TONIGHT AND EARLY THURSDAY MORNING. MEDIUM ON PRECIPITATION TYPE. * MEDIUM THAT LLWS WILL REMAIN MARGINAL THROUGH THE EVENING. * HIGH IN MVFR CIGS LATE TONIGHT INTO THURSDAY MORNING THOUGH MEDIUM ON TIMING. MEDIUM IN ANY IFR OCCURRING. KMD //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...MAINLY VFR. NORTH-NORTHWEST WINDS. FRIDAY...VFR. NORTHWEST WINDS. SATURDAY...CHANCE OF SNOW AND IFR DURING THE NIGHT. SOUTHWEST WINDS. SUNDAY...SNOW AND IFR LIKELY. NORTHEAST WINDS. MONDAY...CHANCE OF SNOW WITH MVFR LIKELY. IFR POSSIBLE. NORTHWEST WINDS. TUESDAY...CHANCE OF SNOW DURING THE NIGHT. SOUTHWEST WINDS. MTF && .MARINE... 158 AM CST AN ACTIVE PERIOD WILL UNFOLD OVER LAKE MICHIGAN THROUGH THIS FORECAST THANKS TO THE PROGRESSIVE NATURE IN THE WEATHER PATTERN. HIGH PRESSURE EARLY THIS MORNING WILL EXIT THE PICTURE AND A QUICKLY APPROACHING LOW PRESSURE FROM THE WEST WILL BRING INCREASING SOUTHERLY WINDS LATER TODAY INTO THIS EVENING. DURING THE EVENING THERE IS A PERIOD WHERE OCCASIONAL GALES SHOULD OCCUR ACROSS THE SOUTHERN HALF AS SOME INSTABILITY WILL BE PRESENT WITH GALE FORCE WINDS ONLY 1000-1500 FT OFF THE WATER SURFACE. THE LOW SHOULD BE ELONGATED RIGHT DOWN THE AXIS OF THE LAKE AROUND 6 AM THURSDAY BEFORE IT QUICKLY MOVES EAST. THIS WILL RESULT IN STOUT NORTHWEST WINDS AND COLD ADVECTION ACROSS THE LAKE WITH WHAT LOOKS LIKE DEFINITE GALES FOR AT LEAST THE OPEN WATER...INCLUDING 40 KTS WITH 45 KTS EVEN POSSIBLE ESPECIALLY IN THE NORTH. THIS LIKELY WILL BRING SOME FREEZING SPRAY THURSDAY NIGHT TO THE OPEN WATER. AT THIS TIME FORECAST INGREDIENTS ARE A LITTLE SHY FOR HEAVY FREEZING SPRAY SO NO WATCH FOR THAT ISSUED BUT WILL NEED TO BE MONITORED. HAVE OPTED TO GO WITH A GALE WATCH FOR BEHIND THE LOW PRESSURE AS THAT TIME PERIOD WILL BE THE HIGHEST WINDS WITH THE SYSTEM. WILL JUST MENTION OCCASIONAL GALES ON THE FRONT SIDE DURING THIS EVENING ACROSS MAINLY THE SOUTH HALF. SMALL CRAFT ADVISORY CONDITIONS WILL OBVIOUSLY EXIST A GOOD AMOUNT OF THIS TIME ON THE ILLINOIS AND INDIANA NEAR SHORES. WITH A SHORT 4-6 HOUR RESPITE CENTERED ON DAYBREAK THURSDAY AS THE LOW PASSES...HAVE OPTED TO NOT EXTEND THE CURRENT SMALL CRAFT ADVISORY...BUT ONE WILL DEFINITELY BE NEEDED FOR THURSDAY AFTERNOON AND NIGHT...AND FOR THE INDIANA SHORE INTO FRIDAY. THE GALE WATCH DOES INCLUDE PARTS OF THE INDIANA NEARSHORE THAT WILL FEEL THE GREATER FETCH OF ONSHORE WINDS AND THUS COULD REALIZE GALES THURSDAY AFTERNOON AND EVENING. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS UNTIL 4 AM THURSDAY. GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON THURSDAY TO 3 AM FRIDAY. && $$ 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
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1222 PM CST WED JAN 28 2015 .SHORT TERM... 345 AM CST TODAY THROUGH FRIDAY NIGHT... MAIN FORECAST CONCERNS IN THE SHORT TERM ARE CLOUD AND TEMP TRENDS TODAY AND TONIGHT...AND TIMING...COVERAGE AND TYPE OF PRECIPITATION TONIGHT AND THURSDAY AS LOW PRESSURE ORGANIZING OVER THE PLAINS MOVES EAST. RELATIVELY QUIET WEATHER THIS MORNING AS SURFACE HIGH PRESSURE DRIFTS SLOWLY EAST OF THE AREA. SUBSIDENCE ASSOCIATED WITH HEIGHT RISES ALOFT HAS LED TO A STRONG INVERSION AT AROUND 900 HPA HOWEVER PER DVN 00Z SOUNDING...WHICH HAS TRAPPED LOW CLOUDS ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA OVERNIGHT. CLOUDS WERE SLOWLY ERODING FROM THE SOUTHEAST THANKS TO 950-900 HPA WINDS GRADUALLY VEERING TO THE SOUTHEAST AND SOUTH...AND LOWERING SUBSIDENCE INVERSION. RAP GUIDANCE INDICATES SOUTH WINDS WILL INCREASE THIS MORNING AND SHOULD CONTINUE TO LIFT THESE LOWER CLOUDS NORTH TOWARD THE WI BORDER...THOUGH OVERALL NORTH CENTRAL ILLINOIS IS LIKELY TO BE CLOUDIER THAN AREAS SOUTH AND EAST TODAY EVEN AS MID AND HIGH CLOUDS BEGIN TO INCREASE AS WARM ADVECTION DEVELOPS ALOFT. SURFACE LOW PRESSURE IS ALREADY TAKING SHAPE ACROSS THE PLAINS TO OUR WEST THIS MORNING...IN RESPONSE TO A SHORT WAVE TROUGH EMERGING FROM THE CENTRAL/NORTHERN ROCKIES. SURFACE PRESSURE FALLS AHEAD OF THIS DEVELOPING LOW WILL LEAD TO INCREASING SOUTH-SOUTHEAST WINDS NEAR 25 MPH THIS AFTERNOON. DESPITE SOUTHERLY FLOW...LOW LEVEL PARCEL TRAJECTORIES WILL BE LARGELY FROM INDIANA/OHIO WHERE STRONG COOLING HAS OCCURRED NEAR THE SURFACE HIGH THIS MORNING. COMBINED WITH SOME MID/HIGH CLOUD COVER THIS MAY MAKE FOR HIGH TEMPERATURES COMING LATER IN THE DAY WHEN LOW LEVEL WINDS VEER MORE SOUTHERLY AND TAP MILDER AIR CURRENTLY ACROSS THE MISSOURI VALLEY. STRONG SOUTH FLOW WILL CONTINUE TONIGHT AHEAD OF THE APPROACHING SURFACE LOW...ALLOWING TEMPS TO STAY ABOVE FREEZING IN MOST AREAS. GUIDANCE IN GOOD AGREEMENT IN DEVELOPING SOME LIGHT SPOTTY PRECIPITATION ACROSS THE AREA LATE THIS EVENING...EXPANDING OVERNIGHT ESPECIALLY ACROSS NORTHERN/NORTHEASTERN PARTS OF THE FORECAST AREA. FORECAST SOUNDINGS INDICATE WARM LAYER TEMPS ALOFT IN THE +5C RANGE OR BETTER...WITH SATURATION INITIALLY OCCURRING BELOW 700 HPA AND SUPPORTING LIGHT RAIN. WITH BREEZY SOUTH SURFACE WINDS KEEPING TEMPS ABOVE MAINLY ABOVE FREEZING...PRECIPITATION TYPE IS EXPECTED TO REMAIN LIQUID IN MOST LOCATIONS. LOW PROBABILITY DOES EXIST FOR LIGHT FREEZING RAIN ESPECIALLY ACROSS FAR NORTH/NORTHEAST IL...BUT AT THIS TIME FEEL IT IS FAIRLY UNLIKELY. THE SURFACE LOW...AND A PAIR OF UN-PHASED SHORT WAVES....MOVE ACROSS THE CWA DURING THE MORNING AND RESULT IN WINDS SHIFTING TO THE NORTHWEST. THIS BRINGS COLDER AIR INTO THE REGION WITH COLLAPSING THICKNESS FIELDS SUPPORTING LINGERING PRECIPITATION CHANGING OVER FROM LIGHT RAIN TO A BRIEF RAIN/SLEET/SNOW MIX BEFORE ENDING FROM WEST-EAST. MOST PRECIPITATION SHOULD END BY NOON WEST OF ABOUT THE IL/IN STATE LINE...AND SHORTLY AFTER ACROSS NORTHWEST INDIANA. HOWEVER...GUSTY NORTH-NORTHWEST WINDS AND COLDER AIR SPREADING ACROSS LAKE MICHIGAN WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS ACROSS PARTS OF EASTERN LAKE AND PORTER COUNTIES ESPECIALLY THURSDAY EVENING INTO EARLY FRIDAY MORNING. THE REMAINDER OF THE AREA WILL JUST BE BLUSTERY AND COLDER...WITH NORTH-NORTHWEST WINDS GUSTING ABOVE 30 MPH AT TIMES THURSDAY BEFORE SLOWLY DIMINISHING THURSDAY NIGHT. AFTER MORNING HIGHS IN THE MID-UPPER 30S OR EVEN NEAR 40 IN SOME SPOTS...THURSDAY NIGHT LOOKS TO BE COLD WITH LOWS IN THE TEENS TO LOW 20S AND SINGLE DIGIT WIND CHILLS. SURFACE HIGH PRESSURE SPREADS INTO THE AREA AGAIN ON FRIDAY...WITH TEMPERATURES STRUGGLING INTO THE MID-UPPER 20S BUT WITH MUCH LIGHTER WINDS. LAKE SNOW SHOWERS WILL DIMINISH ACROSS NORTHWEST INDIANA AS INVERSION HEIGHTS LOWER AND LOW LEVEL WINDS DIMINISH...WITH SUNSHINE ELSEWHERE. RATZER && .LONG TERM... 345 AM CST SATURDAY THROUGH TUESDAY... THE MAIN FOCUS IN THE EXTENDED PERIOD IS ON A STORM SYSTEM WHICH LOOKS TO LIFT THROUGH THE OHIO VALLEY LATE SATURDAY NIGHT THROUGH SUNDAY. ECMWF/GFS ARE IN RELATIVELY GOOD AGREEMENT IN TAKING SURFACE LOW TRACK ALONG THE OHIO RIVER...THOUGH GFS IS A LITTLE SLOWER AND GEFS ENSEMBLE MEMBERS STILL SHOW QUITE A BIT OF SPREAD IN THEIR SOLUTIONS AT THE SURFACE. GEM ALSO SLOWER AND A BIT FARTHER SOUTH THAN THE OTHER GLOBAL MODELS. DEPENDING UPON HOW THIS SYSTEM EVENTUALLY TRACKS...IT COULD BE A SNOW PRODUCER FOR ALL OR PART OF THE CWA...AS IT TAPS GULF MOISTURE DEFORMATION BAND WOULD LIKELY CROSS CENTRAL IL/IN. GLOBAL MODELS ALSO INDICATE A STRONG SURGE OF ARCTIC AIR IN THE WAKE OF THIS SYSTEM...WITH SIGNIFICANTLY COLDER WEATHER I.E. LOWS +/- SINGLE DIGITS AND HIGHS PERHAPS ONLY IN THE TEENS BY MONDAY/TUESDAY. RATZER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * GUSTY SOUTH-SOUTHEAST SURFACE WINDS THIS AFTERNOON...POSSIBLY STRENGTHENING INTO EVENING. * SCATTERED LIGHT RAIN SHOWERS LIKELY AND MVFR CIGS DEVELOPING OVERNIGHT...AND THE POSSIBILITY OF A BRIEF MIX WITH SNOW AND IFR BEFORE ENDING THURSDAY MORNING. * SOUTH-SOUTHWEST WINDS AT 2000 FT OF AT LEAST 40-45 KT THIS EVENING INTO OVERNIGHT THAT MAY CREATE LOW-LEVEL WIND SHEAR. * NORTHWEST WINDS GUSTING TO AROUND 30 KT DURING THE DAY THURSDAY. KMD //DISCUSSION...UPDATED 18Z... QUITE A FEW AVIATION CONCERNS FOR THIS TAF CYCLE. THE FIRST CENTERS AROUND WINDS. SE WINDS WILL GRADUALLY RAMP UP THIS AFTERNOON AND EVENING WITH SUSTAINED WINDS HOLDING IN THE MID TEENS AND GUSTS INTO 22-24 KT RANGE AHEAD OF LOW PRESSURE MOVING EAST THROUGH THE PLAINS. THE LOW MOVES THROUGH LATE TONIGHT WITH A TRAILING COLD FRONT INTO TOMORROW MORNING. AFTER A PERIOD OF LIGHTER WINDS...NW WINDS RAMP UP QUICKLY MID MORNING THROUGH THE AFTERNOON. NAM/GFS FORECAST SOUNDINGS SHOW GOOD MIXING THAT WILL SUPPORT 30 KT OR SO GUSTS THROUGH THE AFTERNOON. AT THIS POINT LLWS HAS NOT BEEN INTRODUCED AS WINDS AT 2000 FT WILL REACH 40-45 KT WHICH IS ON THE THRESHOLD...BUT WITH THE CONTINUED GUSTINESS IT IS MARGINAL AT THIS POINT. DURING PERIODS OF LESS FREQUENT GUSTS THERE COULD BE SOME LLWS. OTHER CONCERNS REVOLVE AROUND PRECIPITATION EVOLUTION AND TYPE THROUGH EARLY THURSDAY. SEVERAL MODELS SHOW SOME DECENT LIFT IN THE WARM ADVECTIVE REGIME THIS EVENING. IN SPITE OF THIS...GUIDANCE IS MIXED AS TO HOW MUCH MOISTURE THERE WILL ACTUALLY BE TO SUPPORT PRECIPITATION DURING THIS INITIAL TIME FRAME. IF PRECIP WERE TO DEVELOP IN THE 4Z-8Z TIME FRAME...SURFACE TEMPERATURES COULD SUPPORT FZRA. HAVE ONLY GONE WITH A VCSH GIVEN THE LACK OF MOISTURE ON SOME GUIDANCE...BUT WILL BE A PERIOD TO WATCH. BETTER CHANCES OF PRECIPITATION COME WITH THE COLD FRONT LATE TONIGHT INTO EARLY THURSDAY. PRECIP LOOKS TO BE A RAIN OR DRIZZLE BEFORE TAPERING TO A RAIN SNOW MIX. SURFACE TEMPS HOLD AT OR ABOVE 32 FOR MOST OF THE PRECIP THUS LITTLE TO NO ACCUMULATION IS EXPECTED. KMD //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH IN WIND DIRECTION AND SPEED THROUGH THIS EVENING...INCLUDING THE WIND DIRECTION REMAINING SLIGHTLY EAST OF SOUTH. * MEDIUM IN PRECIPITATION OCCURRING AT THE AIRFIELD LATER TONIGHT AND EARLY THURSDAY MORNING. MEDIUM ON PRECIPITATION TYPE. * MEDIUM THAT LLWS WILL REMAIN MARGINAL THROUGH THE EVENING. * HIGH IN MVFR CIGS LATE TONIGHT INTO THURSDAY MORNING THOUGH MEDIUM ON TIMING. MEDIUM IN ANY IFR OCCURRING. KMD //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...MAINLY VFR. NORTH-NORTHWEST WINDS. FRIDAY...VFR. NORTHWEST WINDS. SATURDAY...CHANCE OF SNOW AND IFR DURING THE NIGHT. SOUTHWEST WINDS. SUNDAY...SNOW AND IFR LIKELY. NORTHEAST WINDS. MONDAY...CHANCE OF SNOW WITH MVFR LIKELY. IFR POSSIBLE. NORTHWEST WINDS. TUESDAY...CHANCE OF SNOW DURING THE NIGHT. SOUTHWEST WINDS. MTF && .MARINE... 158 AM CST AN ACTIVE PERIOD WILL UNFOLD OVER LAKE MICHIGAN THROUGH THIS FORECAST THANKS TO THE PROGRESSIVE NATURE IN THE WEATHER PATTERN. HIGH PRESSURE EARLY THIS MORNING WILL EXIT THE PICTURE AND A QUICKLY APPROACHING LOW PRESSURE FROM THE WEST WILL BRING INCREASING SOUTHERLY WINDS LATER TODAY INTO THIS EVENING. DURING THE EVENING THERE IS A PERIOD WHERE OCCASIONAL GALES SHOULD OCCUR ACROSS THE SOUTHERN HALF AS SOME INSTABILITY WILL BE PRESENT WITH GALE FORCE WINDS ONLY 1000-1500 FT OFF THE WATER SURFACE. THE LOW SHOULD BE ELONGATED RIGHT DOWN THE AXIS OF THE LAKE AROUND 6 AM THURSDAY BEFORE IT QUICKLY MOVES EAST. THIS WILL RESULT IN STOUT NORTHWEST WINDS AND COLD ADVECTION ACROSS THE LAKE WITH WHAT LOOKS LIKE DEFINITE GALES FOR AT LEAST THE OPEN WATER...INCLUDING 40 KTS WITH 45 KTS EVEN POSSIBLE ESPECIALLY IN THE NORTH. THIS LIKELY WILL BRING SOME FREEZING SPRAY THURSDAY NIGHT TO THE OPEN WATER. AT THIS TIME FORECAST INGREDIENTS ARE A LITTLE SHY FOR HEAVY FREEZING SPRAY SO NO WATCH FOR THAT ISSUED BUT WILL NEED TO BE MONITORED. HAVE OPTED TO GO WITH A GALE WATCH FOR BEHIND THE LOW PRESSURE AS THAT TIME PERIOD WILL BE THE HIGHEST WINDS WITH THE SYSTEM. WILL JUST MENTION OCCASIONAL GALES ON THE FRONT SIDE DURING THIS EVENING ACROSS MAINLY THE SOUTH HALF. SMALL CRAFT ADVISORY CONDITIONS WILL OBVIOUSLY EXIST A GOOD AMOUNT OF THIS TIME ON THE ILLINOIS AND INDIANA NEAR SHORES. WITH A SHORT 4-6 HOUR RESPITE CENTERED ON DAYBREAK THURSDAY AS THE LOW PASSES...HAVE OPTED TO NOT EXTEND THE CURRENT SMALL CRAFT ADVISORY...BUT ONE WILL DEFINITELY BE NEEDED FOR THURSDAY AFTERNOON AND NIGHT...AND FOR THE INDIANA SHORE INTO FRIDAY. THE GALE WATCH DOES INCLUDE PARTS OF THE INDIANA NEARSHORE THAT WILL FEEL THE GREATER FETCH OF ONSHORE WINDS AND THUS COULD REALIZE GALES THURSDAY AFTERNOON AND EVENING. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...3 PM WEDNESDAY TO 4 AM THURSDAY. GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON THURSDAY TO 3 AM FRIDAY. && $$ 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
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 AM CST WED JAN 28 2015 .SHORT TERM... 345 AM CST TODAY THROUGH FRIDAY NIGHT... MAIN FORECAST CONCERNS IN THE SHORT TERM ARE CLOUD AND TEMP TRENDS TODAY AND TONIGHT...AND TIMING...COVERAGE AND TYPE OF PRECIPITATION TONIGHT AND THURSDAY AS LOW PRESSURE ORGANIZING OVER THE PLAINS MOVES EAST. RELATIVELY QUIET WEATHER THIS MORNING AS SURFACE HIGH PRESSURE DRIFTS SLOWLY EAST OF THE AREA. SUBSIDENCE ASSOCIATED WITH HEIGHT RISES ALOFT HAS LED TO A STRONG INVERSION AT AROUND 900 HPA HOWEVER PER DVN 00Z SOUNDING...WHICH HAS TRAPPED LOW CLOUDS ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA OVERNIGHT. CLOUDS WERE SLOWLY ERODING FROM THE SOUTHEAST THANKS TO 950-900 HPA WINDS GRADUALLY VEERING TO THE SOUTHEAST AND SOUTH...AND LOWERING SUBSIDENCE INVERSION. RAP GUIDANCE INDICATES SOUTH WINDS WILL INCREASE THIS MORNING AND SHOULD CONTINUE TO LIFT THESE LOWER CLOUDS NORTH TOWARD THE WI BORDER...THOUGH OVERALL NORTH CENTRAL ILLINOIS IS LIKELY TO BE CLOUDIER THAN AREAS SOUTH AND EAST TODAY EVEN AS MID AND HIGH CLOUDS BEGIN TO INCREASE AS WARM ADVECTION DEVELOPS ALOFT. SURFACE LOW PRESSURE IS ALREADY TAKING SHAPE ACROSS THE PLAINS TO OUR WEST THIS MORNING...IN RESPONSE TO A SHORT WAVE TROUGH EMERGING FROM THE CENTRAL/NORTHERN ROCKIES. SURFACE PRESSURE FALLS AHEAD OF THIS DEVELOPING LOW WILL LEAD TO INCREASING SOUTH-SOUTHEAST WINDS NEAR 25 MPH THIS AFTERNOON. DESPITE SOUTHERLY FLOW...LOW LEVEL PARCEL TRAJECTORIES WILL BE LARGELY FROM INDIANA/OHIO WHERE STRONG COOLING HAS OCCURRED NEAR THE SURFACE HIGH THIS MORNING. COMBINED WITH SOME MID/HIGH CLOUD COVER THIS MAY MAKE FOR HIGH TEMPERATURES COMING LATER IN THE DAY WHEN LOW LEVEL WINDS VEER MORE SOUTHERLY AND TAP MILDER AIR CURRENTLY ACROSS THE MISSOURI VALLEY. STRONG SOUTH FLOW WILL CONTINUE TONIGHT AHEAD OF THE APPROACHING SURFACE LOW...ALLOWING TEMPS TO STAY ABOVE FREEZING IN MOST AREAS. GUIDANCE IN GOOD AGREEMENT IN DEVELOPING SOME LIGHT SPOTTY PRECIPITATION ACROSS THE AREA LATE THIS EVENING...EXPANDING OVERNIGHT ESPECIALLY ACROSS NORTHERN/NORTHEASTERN PARTS OF THE FORECAST AREA. FORECAST SOUNDINGS INDICATE WARM LAYER TEMPS ALOFT IN THE +5C RANGE OR BETTER...WITH SATURATION INITIALLY OCCURRING BELOW 700 HPA AND SUPPORTING LIGHT RAIN. WITH BREEZY SOUTH SURFACE WINDS KEEPING TEMPS ABOVE MAINLY ABOVE FREEZING...PRECIPITATION TYPE IS EXPECTED TO REMAIN LIQUID IN MOST LOCATIONS. LOW PROBABILITY DOES EXIST FOR LIGHT FREEZING RAIN ESPECIALLY ACROSS FAR NORTH/NORTHEAST IL...BUT AT THIS TIME FEEL IT IS FAIRLY UNLIKELY. THE SURFACE LOW...AND A PAIR OF UN-PHASED SHORT WAVES....MOVE ACROSS THE CWA DURING THE MORNING AND RESULT IN WINDS SHIFTING TO THE NORTHWEST. THIS BRINGS COLDER AIR INTO THE REGION WITH COLLAPSING THICKNESS FIELDS SUPPORTING LINGERING PRECIPITATION CHANGING OVER FROM LIGHT RAIN TO A BRIEF RAIN/SLEET/SNOW MIX BEFORE ENDING FROM WEST-EAST. MOST PRECIPITATION SHOULD END BY NOON WEST OF ABOUT THE IL/IN STATE LINE...AND SHORTLY AFTER ACROSS NORTHWEST INDIANA. HOWEVER...GUSTY NORTH-NORTHWEST WINDS AND COLDER AIR SPREADING ACROSS LAKE MICHIGAN WILL LIKELY SUPPORT LAKE EFFECT SNOW SHOWERS ACROSS PARTS OF EASTERN LAKE AND PORTER COUNTIES ESPECIALLY THURSDAY EVENING INTO EARLY FRIDAY MORNING. THE REMAINDER OF THE AREA WILL JUST BE BLUSTERY AND COLDER...WITH NORTH-NORTHWEST WINDS GUSTING ABOVE 30 MPH AT TIMES THURSDAY BEFORE SLOWLY DIMINISHING THURSDAY NIGHT. AFTER MORNING HIGHS IN THE MID-UPPER 30S OR EVEN NEAR 40 IN SOME SPOTS...THURSDAY NIGHT LOOKS TO BE COLD WITH LOWS IN THE TEENS TO LOW 20S AND SINGLE DIGIT WIND CHILLS. SURFACE HIGH PRESSURE SPREADS INTO THE AREA AGAIN ON FRIDAY...WITH TEMPERATURES STRUGGLING INTO THE MID-UPPER 20S BUT WITH MUCH LIGHTER WINDS. LAKE SNOW SHOWERS WILL DIMINISH ACROSS NORTHWEST INDIANA AS INVERSION HEIGHTS LOWER AND LOW LEVEL WINDS DIMINISH...WITH SUNSHINE ELSEWHERE. RATZER && .LONG TERM... 345 AM CST SATURDAY THROUGH TUESDAY... THE MAIN FOCUS IN THE EXTENDED PERIOD IS ON A STORM SYSTEM WHICH LOOKS TO LIFT THROUGH THE OHIO VALLEY LATE SATURDAY NIGHT THROUGH SUNDAY. ECMWF/GFS ARE IN RELATIVELY GOOD AGREEMENT IN TAKING SURFACE LOW TRACK ALONG THE OHIO RIVER...THOUGH GFS IS A LITTLE SLOWER AND GEFS ENSEMBLE MEMBERS STILL SHOW QUITE A BIT OF SPREAD IN THEIR SOLUTIONS AT THE SURFACE. GEM ALSO SLOWER AND A BIT FARTHER SOUTH THAN THE OTHER GLOBAL MODELS. DEPENDING UPON HOW THIS SYSTEM EVENTUALLY TRACKS...IT COULD BE A SNOW PRODUCER FOR ALL OR PART OF THE CWA...AS IT TAPS GULF MOISTURE DEFORMATION BAND WOULD LIKELY CROSS CENTRAL IL/IN. GLOBAL MODELS ALSO INDICATE A STRONG SURGE OF ARCTIC AIR IN THE WAKE OF THIS SYSTEM...WITH SIGNIFICANTLY COLDER WEATHER I.E. LOWS +/- SINGLE DIGITS AND HIGHS PERHAPS ONLY IN THE TEENS BY MONDAY/TUESDAY. RATZER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * GUSTY SOUTH-SOUTHEAST SURFACE WINDS DEVELOPING BY EARLY AFTERNOON AND STRENGTHENING INTO EVENING. * SCATTERED LIGHT RAIN SHOWERS LIKELY AND MVFR CIGS DEVELOPING OVERNIGHT...AND THE POSSIBILITY OF A BRIEF MIX WITH SNOW AND IFR VISIBILITY BEFORE ENDING THURSDAY MORNING. * SOUTH-SOUTHWEST WINDS AT 2000 FT OF AT LEAST 50 KT THIS EVENING INTO OVERNIGHT THAT MAY CREATE LOW-LEVEL WIND SHEAR. * NORTHWEST WINDS GUSTING TO AROUND 30 KT DURING THE DAY THURSDAY. KMD //DISCUSSION...UPDATED 12Z... CURRENT BATCH OF MVFR CIGS ACROSS NORTHWEST ILLINOIS EARLY THIS MORNING IS BEING STEERED ON SOUTHERLY WINDS EARLY THIS MORNING...WITH RFD LIKELY TO EXPERIENCE AT LEAST TEMPORARY 2000 FT CIGS OR SO THROUGH MID-MORNING. WITH THE APPROACH OF LOW PRESSURE...SOUTH-SOUTHEAST WINDS WILL INCREASE WITH GUSTS LIKELY IN THE AFTERNOON AND PERSISTING...AND LIKELY STRENGTHENING...INTO THE EVENING AS STRONG PRESSURE FALLS ENVELOP THE REGION. GIVEN THE CURRENT AND FORECAST PLACEMENT OF THE LOW PRESSURE...THE WIND DIRECTION SHOULD BE EAST OF SOUTH MUCH OF TODAY AND EARLY THIS EVENING...BEFORE GRADUALLY VEERING AHEAD OF A FRONT LATE TONIGHT. A CHANNEL OF STRONG SOUTHWEST WINDS ALOFT...AROUND 2000-3000 FT...ARE LIKELY TO BE 50 PLUS KNOTS TONIGHT AND COULD RESULT IN SOME LOW-LEVEL WIND SHEAR...ALTHOUGH SURFACE WINDS WILL REMAIN ALSO INCREASED IN SOMEWHAT MIXED CONDITIONS. THE COLD FRONT WILL PASS IN THE PRE-DAWN HOURS THURSDAY. AHEAD OF THIS FRONT SATURATION SHOULD SLOWLY OCCUR NEAR THE INVERSION LEVEL...WHICH IS EXPECTED TO BE AROUND 2000-3000 FT SO CIGS OF THAT HEIGHT SHOULD GRADUALLY DEVELOP AS TONIGHT PROGRESSES. IN ADDITION...THERE WILL BE POTENTIAL FOR SCATTERED RAIN SHOWERS...WITH ANY RAIN POSSIBLY CHANGING TO A RAIN AND SNOW MIX AFTER SUNRISE THURSDAY. ANY MIX IS NOT LIKELY TO LAST LONG BEFORE ENDING...SO ACCUMULATIONS SHOULD BE ONLY A TRACE. //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH IN WIND DIRECTION AND SPEED TODAY AND THIS EVENING...INCLUDING THE WIND DIRECTION REMAINING SLIGHTLY EAST OF SOUTH. * MEDIUM IN PRECIPITATION OCCURRING AT THE AIRFIELD LATER TONIGHT AND EARLY THURSDAY MORNING. * HIGH IN MVFR CIGS LATE TONIGHT INTO THURSDAY MORNING. MEDIUM IN ANY IFR OCCURRING. KMD //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...MAINLY VFR. NORTH-NORTHWEST WINDS. FRIDAY...VFR. NORTHWEST WINDS. SATURDAY...CHANCE OF SNOW AND IFR DURING THE NIGHT. SOUTHWEST WINDS. SUNDAY...SNOW AND IFR LIKELY. NORTHEAST WINDS. MONDAY...CHANCE OF SNOW WITH MVFR LIKELY. IFR POSSIBLE. NORTHWEST WINDS. TUESDAY...CHANCE OF SNOW DURING THE NIGHT. SOUTHWEST WINDS. MTF && .MARINE... 158 AM CST AN ACTIVE PERIOD WILL UNFOLD OVER LAKE MICHIGAN THROUGH THIS FORECAST THANKS TO THE PROGRESSIVE NATURE IN THE WEATHER PATTERN. HIGH PRESSURE EARLY THIS MORNING WILL EXIT THE PICTURE AND A QUICKLY APPROACHING LOW PRESSURE FROM THE WEST WILL BRING INCREASING SOUTHERLY WINDS LATER TODAY INTO THIS EVENING. DURING THE EVENING THERE IS A PERIOD WHERE OCCASIONAL GALES SHOULD OCCUR ACROSS THE SOUTHERN HALF AS SOME INSTABILITY WILL BE PRESENT WITH GALE FORCE WINDS ONLY 1000-1500 FT OFF THE WATER SURFACE. THE LOW SHOULD BE ELONGATED RIGHT DOWN THE AXIS OF THE LAKE AROUND 6 AM THURSDAY BEFORE IT QUICKLY MOVES EAST. THIS WILL RESULT IN STOUT NORTHWEST WINDS AND COLD ADVECTION ACROSS THE LAKE WITH WHAT LOOKS LIKE DEFINITE GALES FOR AT LEAST THE OPEN WATER...INCLUDING 40 KTS WITH 45 KTS EVEN POSSIBLE ESPECIALLY IN THE NORTH. THIS LIKELY WILL BRING SOME FREEZING SPRAY THURSDAY NIGHT TO THE OPEN WATER. AT THIS TIME FORECAST INGREDIENTS ARE A LITTLE SHY FOR HEAVY FREEZING SPRAY SO NO WATCH FOR THAT ISSUED BUT WILL NEED TO BE MONITORED. HAVE OPTED TO GO WITH A GALE WATCH FOR BEHIND THE LOW PRESSURE AS THAT TIME PERIOD WILL BE THE HIGHEST WINDS WITH THE SYSTEM. WILL JUST MENTION OCCASIONAL GALES ON THE FRONT SIDE DURING THIS EVENING ACROSS MAINLY THE SOUTH HALF. SMALL CRAFT ADVISORY CONDITIONS WILL OBVIOUSLY EXIST A GOOD AMOUNT OF THIS TIME ON THE ILLINOIS AND INDIANA NEAR SHORES. WITH A SHORT 4-6 HOUR RESPITE CENTERED ON DAYBREAK THURSDAY AS THE LOW PASSES...HAVE OPTED TO NOT EXTEND THE CURRENT SMALL CRAFT ADVISORY...BUT ONE WILL DEFINITELY BE NEEDED FOR THURSDAY AFTERNOON AND NIGHT...AND FOR THE INDIANA SHORE INTO FRIDAY. THE GALE WATCH DOES INCLUDE PARTS OF THE INDIANA NEARSHORE THAT WILL FEEL THE GREATER FETCH OF ONSHORE WINDS AND THUS COULD REALIZE GALES THURSDAY AFTERNOON AND EVENING. MTF && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744- LMZ745...3 PM WEDNESDAY TO 4 AM THURSDAY. GALE WATCH...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-LMZ745-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON THURSDAY TO 3 AM FRIDAY. && $$ 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
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
445 PM EST WED JAN 28 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 444 PM EST WED JAN 28 2015 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A PAIR OF SHORTWAVES TO THE W AND NW. ONE IS MOVING OUT OF WY/CO INTO THE WRN PLAINS AND THE OTHER IS MOVING FROM SRN SASKATCHEWAN INTO SRN MANITOBA. AHEAD OF THESE FEATURES...A RIBBON OF STRENGTHENING WAA/ISENTROPIC ASCENT IS SPREADING ESE ACROSS NRN ONTARIO AND THE UPPER GREAT LAKES UNDERNEATH RIGHT ENTRANCE OF UPPER JET CURVING FROM NRN ONTARIO DOWN THRU THE CNTRL APPALACHIANS. REGIONAL RADARS SHOW A STREAK OF RADAR RETURNS EXTENDING ESE FROM SE MANITOBA ACROSS ADJACENT NRN ONTARIO AND OVER LAKE SUPERIOR/ERN UPPER MI. THE ASCENT HAS BEEN SUFFICIENT TO ERODE DRY AIR AT THE LOWER LEVELS AND ALLOW SOME -SN TO REACH THE GROUND FROM THE TIP OF THE KEWEENAW INTO THE NCNTRL AND ERN FCST AREA. PAIR OF SHORTWAVES WILL CONTINUE MOVING ESE TONIGHT WITH THE NRN STREAM WAVE THE MORE IMPORTANT FEATURE FOR THE WEATHER HERE. AS THE WAVE APPROACHES...ISENTROPIC ASCENT ON THE 295K SFC INCREASES TONIGHT...MOST NOTABLY OVER THE E HALF OF UPPER MI. WHILE IT WILL BE TOO WARM FOR ANY LAKE ENHANCEMENT OFF LAKE MICHIGAN...THE FLOW OFF THE LAKE WILL STILL AID THE MOISTENING OF THE LOW LEVELS. OVER THE W...THE WINDOW OF COLUMN MOISTENING IS SHORTER BEFORE THE ISENTROPIC ASCENT DEPARTS OVERNIGHT. THUS...PCPN AMOUNTS TONIGHT WILL BE LIGHTEST OVER THE W AND GREATER OVER THE E. 295K SFC SHOWS MIXING RATIOS OF 3-4G/KG AVBL...SUGGESTING THE POTENTIAL FOR 3-4INCHES OF SNOW FOR THE ROUGHLY 6HRS OF ASCENT EXPECTED. 4 INCHES IS LIKELY TOO HIGH SINCE SNOW TO WATER RATIOS SHOULD BE ON THE LOWER SIDE. AS IT IS...WILL PROBABLY BE CLOSE TO ADVY THRESHOLD OVER THE FAR E... MAINLY LUCE COUNTY...AS 12HR SNOW ACCUMULATIONS FROM LATE EVENING TO LATE THU MORNING WILL BE NEAR 3 INCHES. SNOW ACCUMULATIONS WILL BE STEADILY LIGHTER TO THE W...DOWN TO LESS THAN 1 INCH FAR W AND ALONG THE WI BORDER. LATE TONIGHT INTO THU MORNING...FCST SOUNDINGS SUPPORT THE POTENTIAL FOR SOME -FZDZ AS MID LEVEL MOISTURE/SYNOPTIC SNOW EXIT...LEAVING A LOW LEVEL MOIST LAYER THAT HAS TEMPS HIGHER THAN -10C. WILL INCLUDE MENTION OF -FZDZ WHERE WINDS WILL BE UPSLOPING. COLD FRONT PASSES ACROSS UPPER MI THU MORNING. DESPITE INCREASING WIND FIELDS...INITIAL CAA IS WEAK AS THERMAL GRADIENT IS DISPLACED OFF TO THE NW...BUT CAA INCREASES QUICKLY IN THE AFTN. 850MB TEMPS AROUND -10C IN THE MORNING WILL FALL TO NEAR -20C BY 00Z FRI...AND THIS WILL RESULT IN FALLING SFC TEMPS...ESPECIALLY IN THE AFTN. LAST OF THE SYNOPTIC SNOW WILL END OVER THE E IN THE MORNING. OTHERWISE...THERE MAY NOT BE TOO MUCH IN THE WAY OF PCPN (-SN/-FZDZ) DURING THE MORNING AWAY FROM AREAS THAT SEE UPSLOPING UNDER NW WINDS. AS COLDER AIR ARRIVES IN THE AFTN...NW/NNW FLOW LES WILL INCREASE IN COVERAGE WITH DGZ DROPPING INTO THE CONVECTIVE LAYER. STRONG SUBSIDENCE/DEEP LAYER QVECTOR DIVERGENCE WILL LIMIT LES INTENSITY. SO FOR THE MOST PART...EXPECT ACCUMULATIONS MOSTLY AROUND 1 INCH IN THE AFTN. STRONG WINDS WILL DISPLACE LES A LITTLE FARTHER INLAND THAN NORMAL. SPEAKING OF WINDS...FAVORABLE POSTIONING OF PRES RISE/FALL COUPLET WILL RESULT IN AN ADDITIVE ISALLOBARIC WIND COMPONENT. COMBINED WITH 925MB WINDS INCREASING TO AROUND 40KT...CONDITIONS WILL BECOME BLUSTERY ACROSS THE AREA. ALONG THE LAKE SUPERIOR SHORE AROUND THE TIP OF THE KEWEENAW AND FROM BIG BAY EASTWARD...WINDS WILL PROBABLY GUST TO 35 TO 45 MPH IN THE AFTN. DEPENDING ON HOW QUICKLY LES INCREASES IN THE AFTN...BLSN COULD BECOME A SIGNIFICANT ISSUE NEAR THE LAKE. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 327 PM EST WED JAN 28 2015 A SHORTWAVE TROUGH WILL BE OVER THE CWA AT 00Z FRI...WITH MOST OF THE ASSOCIATED FORCING E OF THE CWA BY THAT TIME. NW-NNW LOW LEVEL WINDS AND 850MB TEMPS AS LOW AS -22C WILL KEEP SNOW GOING IN THE NW- NNW WINDS SNOWBELTS THU NIGHT...BUT A SFC RIDGE PUSHING THROUGH ON FRI WILL LEAD TO A DIMINISHING TREND IN THE LES AS WINDS BECOME ANTI- CYCLONIC. WINDS TURN SWLY BY FRI NIGHT BEHIND THE TROUGH AND AHEAD OF A CLIPPER SHORTWAVE/SFC TROUGH THAT WILL MOVE THROUGH LATE FRI NIGHT/EARLY SAT. NW WIND LES WILL RAMP UP ALONG AND BEHIND THE TROUGH AS 850MB WINDS AS LOW AS -30C SWEEP ACROSS THE AREA. TEMPS LOOK TO MODERATE SOME MON INTO TUE AS A RIDGE MOVES THROUGH...WITH ANOTHER COLD BLAST SHOWN BY MODELS TOWARD THE MIDDLE OF NEXT WEEK. OVER THE NEXT WEEK THE NW WINDS SNOWBELTS MAINLY E OF MARQUETTE WILL SEE THE MOST SNOWFALL...WITH PROLONGED LIGHT TO MODERATE SNOWFALL. WITH THE VERY COLD AIRMASS... GROWTH WILL BE ADVERSELY IMPACTED...WITH SMALL SNOW FLAKES EFFICIENT AT REDUCING VIS THE PREDOMINANT CONDITION. COLD TEMPS ARE A CERTAINTY...ESPECIALLY SUN AND MON WHEN HIGHS WILL NOT MAKE IT OUT OF THE SINGLE DIGITS ABOVE ZERO IN MOST LOCATIONS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1247 PM EST WED JAN 28 2015 BASED ON OBS AROUND THE AREA...IT APPEARS VFR CONDITIONS WILL PREVAIL AT KIWD/KCMX/KSAW THIS AFTN. WILL NEED TO WATCH LOW CLOUDS STREAMING N UP LAKE MICHIGAN. AS WINDS BACK SLIGHTLY THIS AFTN... THESE LOWER CLOUDS/MVFR CIGS MAY REACH KSAW EARLIER THAN ANTICIPATED. AT KIWD...DOWNSLOPE WIND COMPONENT SHOULD PREVENT THE LOWER CLOUDS IN NRN WI FROM REACHING THE TERMINAL. DISTURBANCE APPROACHING TONIGHT WILL BRING SOME -SN/DETERIORATING CONDITIONS. ALL TERMINALS WILL LIKELY FALL TO IFR WITH A FEW HRS OF LIFR POSSIBLE OVERNIGHT. THERE MAY BE A LITTLE -FZDZ LATE TONIGHT AT KIWD. PASSAGE OF COLD FRONT EARLY THU MORNING WILL BRING INCREASING...GUSTY NW WINDS...ESPECIALLY AT THE MORE EXPOSED KCMX TERMINAL. OTHERWISE...EXPECT IMPROVEMENT TO MVFR AT ALL TERMINALS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 444 PM EST WED JAN 28 2015 AHEAD OF AN APPROACHING LOW PRES TROF...S WINDS OF 20-30KT ARE EXPECTED OVER ERN LAKE SUPERIOR TONIGHT. AS IS TYPICAL FOR SOUTHERLY WINDS...WINDS WILL BE LIGHTER OVER THE W. THE TROF WILL PASS ACROSS THE LAKE THU MORNING. BEHIND IT...N TO NW WINDS WILL INCREASE TO 20- 30KT OVER WRN LAKE SUPERIOR. OVER THE CNTRL AND ERN LAKE...WINDS WILL INCREASE TO GALE FORCE (GUSTS TO AROUND 40KT) FOR THU AFTN AND NIGHT. COMBINATION OF MUCH COLDER AIR/STRONG WINDS AND BUILDING WAVES WILL LEAD TO HVY FREEZING SPRAY THU AFTN UNTIL EARLY FRI MORNING WHEN WINDS/WAVES DIMINISH WITH THE CLOSER APPROACH OF CANADIAN HIGH PRES. AFTER A PERIOD OF LIGHTER WINDS MOSTLY UNDER 20KT FRI AFTN/NIGHT...WINDS WILL INCREASE AGAIN TO 20-30KT SAT...ESPECIALLY SAT AFTN/NIGHT...IN THE WAKE OF A LOW PRES TROUGH. GALES MAY OCCUR OVER PORTIONS OF CNTRL LAKE SUPERIOR. WINDS SHOULD DIMINISH FOR A TIME SUN BEFORE INCREASING AGAIN MON. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 1 PM THURSDAY TO 7 AM EST FRIDAY FOR LSZ264-266-267. GALE WARNING FROM 1 PM THURSDAY TO 4 AM EST FRIDAY FOR LSZ267. GALE WARNING FROM 10 AM THURSDAY TO 4 AM EST FRIDAY FOR LSZ265- 266. GALE WARNING FROM 7 AM THURSDAY TO 1 AM EST FRIDAY FOR LSZ263- 264. HEAVY FREEZING SPRAY WARNING FROM 1 PM THURSDAY TO 1 AM EST FRIDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...TITUS AVIATION...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
342 PM CST WED JAN 28 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 342 PM CST WED JAN 28 2015 AN ACTIVE SHORT TERM AHEAD AS A LOW PRESSURE SYSTEM OVER THE EASTERN DAKOTAS SLIDES SOUTHEAST INTO NORTHERN IL BY THURSDAY MORNING. LITTLE ICE IS INDICATED ALOFT OVER NORTHERN AND EASTERN AREAS OF THE FA TONIGHT WITH DEEPENING LOW LEVEL SATURATION. IN ADDITION...SOUTHERLY LOW LEVEL WINDS INCREASE RATHER DRAMATICALLY EARLY TONIGHT ACROSS EASTERN IA ON NORTHWARD INTO WEST CENTRAL WI...WITH A VEERING PROFILE THROUGH 800MB. THIS SHOULD ADD THE TURBULENCE FACTOR TO ALLOW FREEZING DRIZZLE TO BECOME WIDESPREAD ACROSS MUCH OF WEST CENTRAL WI FROM AROUND MID EVENING INTO EARLY THURSDAY MORNING. THIS IS COLLABORATED BY RUNS TODAY OF THE HOPWRF...HRRR AND RAP SHOWING SOME A FEW HUNDREDTHS OF QPF IN THE AFOREMENTIONED AREAS. THEREFORE...ISSUED A FREEZING RAIN ADVISORY FROM 9 PM THROUGH 3 AM FROM RICE LAKE AND LADYSMITH ON SOUTH THROUGH MENOMONIE AND AUGUSTA. THE EVENING SHIFT WILL NEED TO KEEP A CLOSE EYE FROM THE TWIN CITIES ON NORTHWARD WHERE CONFIDENCE ON THE FREEZING DRIZZLE IS LOWER. IN THE WAKE OF THE LOW PRESSURE SYSTEM...THE SURFACE PRESSURE GRADIENT INCREASES SIGNIFICANTLY ACROSS EASTERN SD AND SW MN AFTER MIDNIGHT (12 MILLIBARS). IN FACT...6 HOUR PRESSURE CHANGES ARE NEAR 14 MILLIBARS TO OUR WEST. BUFKIT PROFILE DATA SHOWED TWO THINGS. FIRST...THE NAM PROFILE HAD THE STRONGEST TOP OF THE CHANNEL WINDS NEARING 50 KNOTS ACROSS THE MN RIVER VALLEY AROUND 09Z WHILE THE GFS PROFILE HAD 32 KNOT WINDS AT 200 FEET AT KFRM. THE COMBINATION OF CAA AND A UNIDIRECTIONAL FLOW TO THE TOP OF THE CHANNEL RESULTED IN A WIND ADVISORY BEING ISSUED ALONG AND SOUTH OF A LINE FROM APPLETON TO ALBERT LEA FROM MIDNIGHT THROUGH 9 AM. TEMPERATURES TONIGHT AND THURSDAY ARE INTERESTING. BECAUSE OF THE LOW PRESSURE SYSTEM COMING INTO THE AREA TONIGHT...TEMPERATURES WILL WARM A LITTLE THIS EVENING AND THEN DROP BACK TO A LITTLE BELOW WHERE WE ARE NOW. THURSDAY`S HIGHS WILL BE EARLY IN THE MORNING WITH READINGS FALLING INTO THE TEENS AND LOWER 20S BY THIS TIME THURSDAY AFTERNOON. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 342 PM CST WED JAN 28 2015 BY TOMORROW EVENING...THE PRESSURE GRADIENT WILL BE WEAKENING AND THOSE STRONG NORTHWESTERLY WINDS WILL START TO SLOWLY DECREASE. A SURFACE HIGH WILL DRIFT SOUTHEAST THROUGH OUR AREA OVERNIGHT THROUGH FRIDAY MORNING...WHICH WILL BE ONE OF THE COOLER MORNINGS WE`VE HAD IN TWO+ WEEKS WITH LOWS RANGING FROM NEAR ZERO NEAR LADYSMITH...TO ABOUT 10-15 ABOVE TOWARD REDWOOD FALLS. THE CORE OF THE COLD WILL ESSENTIALLY MISS US TO THE EAST AS IT IS DRAGGED SOUTH BEHIND THE SYSTEM IMPACTING OUT REGION TONIGHT. ON FRIDAY...MODEST WARM AIR ADVECTION WILL ENSUE AND ALLOW TEMPERATURES TO WARM TO VERY NEAR SEASONAL NORMALS. WITH THE COLDER AIR IN PLACE TO THE EAST OF THE AREA...HIGHS WILL STRUGGLE TO REACH 20 IN WEST CENTRAL WI...BUT WARMER AIR THE FURTHER WEST YOU GO WILL YIELD HIGHS IN THE MID 20S FOR EASTERN MN AND LOW 30S ACROSS FAR SOUTHWESTERN MN. THE MAIN CHANGE FROM THE PREVIOUS FORECAST WAS TO THE SATURDAY NIGHT SYSTEM. BOTH THE GFS AND EC RUNS CAME IN WITH A STRONG SURFACE HIGH PUSHING SOUTH FROM SASKATCHEWAN INTO THE UPPER MIDWEST AS THE NORTHERN STREAM JET BUCKLES SOUTHWARD ALLOWING DRY ARCTIC AIR TO ADVANCE FURTHER SOUTH THAN PREVIOUS RUNS INDICATED. THIS IS A GREAT HINDRANCE TO THE POTENTIAL FOR SNOW FROM A SYSTEM DEVELOPING IN THE SOUTHWESTERN CONUS. BUT...THERE IS POTENTIAL FOR LIGHT SNOW FROM A NORTHERN STREAM SHORTWAVE SATURDAY NIGHT. THIS LINES UP WELL WITH AN ENHANCED AREA OF PV ADVECTING SOUTHEAST AND IN CONJUNCTION WITH THE LEFT EXIT REGION OF A 120KT JET STREAK. ANY SNOW THAT DOES FALL THROUGH WILL BE VERY LIGHT WITH THE PRE-EXISTING LOW LEVEL DRY AIR. IT LOOKS LIKE WE`LL BEGIN FEBRUARY WITH TEMPERATURES SLIGHTLY BELOW NORMAL AFTER AN IMPRESSIVE WARM STRETCH FOR THE LAST 3 WEEKS OF JANUARY. BOUTS OF ARCTIC AIR WILL DROP SOUTH THROUGH THE NORTHERN/NORTHEASTERN GREAT LAKES...GIVING US MORE OF A GLANCING BLOW. ANOTHER POSSIBLE CLIPPER SYSTEM COULD BRING ANOTHER SHOT OF VERY LIGHT SNOW MONDAY NIGHT/TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1155 AM CST WED JAN 28 2015 LOW MVFR/IFR CEILINGS WILL DOMINATE THIS AFTERNOON AND TONIGHT WITH SOME POTENTIAL FOR VFR CEILINGS TO DEVELOP THURSDAY AFTERNOON...BUT CONFIDENCE FOR THE VFR CEILINGS IS NOT HIGH AT THIS TIME. THE MAIN CONCERN OVER THE NEXT 12-15 HOURS IS THE THREAT FOR FREEZING DRIZZLE AS A LOW PRESSURE SYSTEM MOVES THROUGH. LITTLE ICE IS INDICATED ALOFT WITH A SATURATED PROFILE FROM 800MB ON DOWNWARD. THIS IS COUPLED WITH A STRONGLY VEERED LOW LEVEL WIND PROFILE. SHORT TERM GUIDANCE INDICATES THE BEST LOCATION IS ALONG AND NORTH OF I-94 IN MN AND ACROSS ALL OF WEST CENTRAL WI WITH TIMING FROM 00Z-09Z. THEREFORE -FZDZ WAS INDICATED IN ALL OF THE TAFS WITH THE EXCEPTION OF KRWF. THE WORST AREA LOOKS TO BE ACROSS WEST CENTRAL WI. IN THE WAKE OF THE LOW...NORTHWEST WINDS WILL INCREASE WITH SPEEDS OF 15 TO 20 KNOTS BEFORE DAYBREAK THURSDAY WITH GUSTS IN THE 25 TO 35 KNOT RANGE. THE HIGHER END SUSTAINED (20KTS) AND GUSTS (35KTS) ARE MOST LIKELY AT KAXN AND KRWF. KMSP...CEILINGS MAY LIFT A LITTLE ABOVE 010 THIS AFTERNOON BUT THE OVERALL TREND IS AT OR BELOW THROUGH EARLY THURSDAY MORNING WITH A SLOW UP TREND THEREAFTER. CONFIDENCE IS INCREASING ON A FEW HOURS OF LIGHT FREEZING DRIZZLE WITH THE BEST TIME DURING THE EVENING. /OUTLOOK FOR KMSP/ THU NGT...MAINLY VFR...CHC MVFR CIGS EARLY. WIND NW 10KT. FRI...VFR. WIND S 5 KT. SAT...MAINLY VFR...CHC MVFR CIGS/-SN. WIND NW 5-10 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST THURSDAY FOR MNZ054-056-064-065-073>075-082>084-091>093. WI...FREEZING RAIN ADVISORY FROM 9 PM THIS EVENING TO 3 AM CST THURSDAY FOR WIZ015-016-025-027-028. && $$ SHORT TERM...RAH LONG TERM...SPD AVIATION...RAH
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1158 AM CST WED JAN 28 2015 .UPDATE... ISSUED AT 1158 AM CST WED JAN 28 2015 NEW 18Z AVIATION DISCUSSION BELOW... UPDATE ISSUED AT 1123 AM CST WED JAN 28 2015 LATE THIS MORNING...PERSISTENT LOW CLOUDS WERE FOUND ACROSS THE NORTHLAND. HAVE NOT BEEN ABLE TO FIND ANY REPORTS OF LOCAL FREEZING DRIZZLE OR OR SNOW AS OF 11 AM. WILL HOLD OFF MENTIONING FZDZ FOR ANY OF THE DAYTIME HOURS...BUT WILL ADD SOME TO THE SOUTHERN CWA THIS EVENING FOR A TIME. UPDATE ISSUED AT 654 AM CST WED JAN 28 2015 ADDED SOME PATCHY FOG THIS MORNING AS SEVERAL LOCATIONS ARE REPORTING. SHOULD SEE THE FOG LIFT BY 15Z. REST OF THE FORECAST ON TRACK. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 353 AM CST WED JAN 28 2015 LOW PRESSURE WAS ORGANIZING IN THE DAKOTAS AT 08Z WITH A FRONTAL BOUNDARY EXTENDING NORTHEASTWARD INTO SOUTHERN MANITOBA AND INTO NW ONTARIO. IN THE WAA AHEAD OF THIS SYSTEM...SOME LIGHT SNOW WAS FALLING OVER THE ARROWHEAD WITH LITTLE ACCUMULATION. NORTH OF THE CANADIAN BORDER...SOME LIGHT FREEZING RAIN WAS OCCURRING RIGHT NEAR THE FRONT FROM WINNIPEG TO NEAR DRYDEN. LATEST SHORT TERM HRRR AND RAP KEEP THIS FREEZING RAIN NORTH OF THE BORDER. THE LIGHT SNOW OVER THE ARROWHEAD IS EXPECTED TO SLOWLY END BY NOON. LITTLE ADDITIONAL ACCUMULATION IS ANTICIPATED. BY THIS AFTERNOON...THE SFC LOW MOVES EASTWARD WITH THE LOW CENTER BEGINS TO REORGANIZE AND DRIFT INTO SOUTHWEST IOWA BY 00Z THURSDAY. MEANWHILE...A MID LEVEL LONG WAVE TROF MOVES OVER THE WESTERN GREAT LAKES. SOME MODEL DIFFERENCES BEGIN TO REVEL THEMSELVES WITH RESPECT TO QPF PLACEMENT AND THE AMOUNT OF COLD AIR FORECAST TO DROP INTO THE FORECAST AREA. THE GFS IS THE MOST ROBUST AND FURTHEST SOUTH WHILE THE ECMWF HAS LIMITED QPF AND KEEPS IT NEAR THE CANADIAN BORDER. HAVE USED A BLENDED APPROACH AND KEPT POPS TO THE NORTHERN HALF OF THE FORECAST AREA BY LATE AFTERNOON. PRECIPITATION TYPE WILL BE ALL SNOW. LATEST FORECAST SOUNDINGS ARE NOT SUPPORTING THE MENTION OF FREEZING RAIN OR FREEZING DRIZZLE AND HAVE REMOVED. TONIGHT...THE MID LEVEL LONG WAVE TROF MOVES EAST OF THE FORECAST AREA BY 12Z THURSDAY. THIS PUSHES THE SFC LOW EAST OF THE AREA AS WELL. BEHIND THIS SYSTEM...A TIGHTENING PRESSURE GRADIENT MOVES OVER THE WESTERN GREAT LAKES AS HIGH PRESSURE BUILDS INTO THE WESTERN DAKOTAS. MADE SOME MINOR CHANGES TO THE POPS AND THEIR TIMING ACROSS THE AREA...WITH THE SNOW ENDING LATE TONIGHT OVER THE SOUTHWEST PORTION OF THE FORECAST AREA TO THE TWIN PORTS LATE TONIGHT. FORECAST SOUNDINGS INDICATE THAT THE PRECIPITATION TYPE WILL BE ALL SNOW AND HAVE REMOVED THE MENTION FREEZING RAIN/FREEZING DRIZZLE AND SLEET. SNOW AMOUNTS WILL BE LIGHT WITH THE HIGHEST AMOUNTS OF AROUND ONE HALF INCH FOUND ALONG THE CANADIAN BORDER. ON THURSDAY...ONLY MADE SOME MINOR CHANGES TO THE POPS AND WEATHER AS MODELS ARE IN VERY GOOD AGREEMENT. WILL STILL HAVE GUSTY WINDS AS THE TIGHT PRESSURE GRADIENT REMAINS UNTIL LATE AFTERNOON WHEN THE AFOREMENTIONED HIGH PRESSURE MOVES INTO THE RED RIVER VALLEY. A NW WIND OVER LAKE SUPERIOR AND CAA WILL LEAD TO SOME LAKE EFFECT SNOW ALONG THE HIGHER TERRAIN OF THE SOUTH SHORE. SNOW AMOUNTS WILL BE LIGHT HOWEVER AS DEEP COLD AIR IS LACKING UNTIL LATE AFTERNOON. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 353 AM CST WED JAN 28 2015 MUCH COLDER AIR ON THE WAY FOR THIS WEEKEND WITH A CHANCE FOR SNOW FROM...YOU GUESSED IT...ANOTHER WEAK CLIPPER SYSTEM. THE LARGE SCALE PATTERN WILL UNDERGO SOME CHANGES THROUGH THE LONG TERM THAT WILL /AT LEAST TEMPORARILY/ PUT A STOP TO WHAT HAS BEEN A LONG PERIOD OF WEAK /AND FRANKLY DISAPPOINTING FOR SNOW LOVERS/ CLIPPERS. TEMPERATURES WILL DROP FROM WHAT HAS BEEN A VERY MILD PATTERN TO A COLDER REGIME...ENDING THE LAST WEEK OF JANUARY WITH TEMPS SIMILAR TO THE FIRST WEEK OF THE MONTH. ON THE SYNOPTIC SCALE A SERIES OF STRONG ARCTIC AIR MASSES WILL DROP DOWN INTO THE NORTHERN PLAINS AND UPPER MIDWEST. LATE THIS WEEK AN AREA OF HIGH PRESSURE WILL MOVE OVER THE AREA THURSDAY NIGHT FOLLOWED BY A WEAK CLIPPER ON FRIDAY/FRIDAY NIGHT. THEN LATE IN THE WEEKEND A DEEP LONGWAVE TROUGH AT MID-LEVELS WILL DESCEND OVER THE MIDWEST LEADING TO VERY COLD AIR ALOFT...850MB TEMPS APPROACHING THE COLDEST 10 PERCENT OF CLIMATOLOGY IN THE MID -20S C /COMPARED TO 00Z TODAY WHEN THEY WERE IN THE WARMEST 10 PERCENT OF CLIMO AT AROUND 0C/. BEST CHANCE FOR SNOWFALL ACROSS THE REGION WILL BE LATE FRIDAY AFTERNOON INTO FRIDAY NIGHT A CLIPPER MOVES ACROSS. GFS AND ECMWF IN GOOD AGREEMENT ON TIMING...WITH ECMWF PESSIMISTIC ON INTENSITY AND GFS A LITTLE STRONGER WITH A DEEPER MOISTURE PROFILE. GEM WAS SLOWER AND NOT AS INTENSE OVERALL...BUT THIS WAS A PRETTY BIG CHANGE FROM 12Z GEM WHICH WAS FASTER AND MUCH MORE AGGRESSIVE ON PRECIP. AT THIS POINT IT LOOKS LIKE A QUICK INCH OR TWO FOR NORTHERN MINNESOTA NORTH OF HIGHWAY TWO. OTHERWISE NO SIGNIFICANT CHANCES FOR PRECIP IN THE SEVEN DAY FOR MUCH OF THE REGION...WITH THE EXCEPTION OF LAKE EFFECT SNOWFALL ALONG PORTIONS OF THE SOUTH SHORE OF LAKE SUPERIOR. LAKE EFFECT SNOWFALL WILL BE PRESENT THROUGH MUCH OF THE LONG TERM PERIOD. ON THURSDAY NIGHT CONDITIONS WILL BE GOOD FOR LAKE EFFECT SNOWFALL ALONG THE HIGHER TERRAIN OF IRON/ASHLAND COUNTIES WITH STEEP LOW LEVEL LAPSE RATES THROUGH 850MB AND GREAT NORTH/NORTHWEST FLOW OVER THE LAKE. ICE COVERAGE ON THE SOUTH SHORE MAY LIMIT THE INTENSITY OF LAKE EFFECT SNOWFALL...AND OPTED TO LEAVE NORTHERN BAYFIELD COUNTY OUT OF HIGHER CHANCES FOR LAKE EFFECT SNOWFALL DUE TO WHAT WOULD BE A VERY LIMITED FETCH LENGTH. LOW LEVEL MOISTURE WILL ALSO BE A FACTOR AS NAM/GFS/ECMWF DEPICT A NEAR-SURFACE DRY LAYER...SO IT MAY TAKE A WHILE TO SATURATE LOW LEVELS AND THUS LIMIT SNOWFALL AMOUNTS. LAKE EFFECT WILL TAPER OFF AS HIGH PRESSURE MOVES OVER LAKE SUPERIOR ON FRIDAY AFTERNOON...BUT RAMP BACK UP AGAIN ON SATURDAY AND THROUGH ABOUT TUESDAY DUE TO THE VERY COLD AIRMASS THAT WILL BE IN PLACE. TEMPS WILL BE ON A DOWNWARD TREND...AND HAVE ADJUSTED SOME OF THE USUAL COLD SPOTS A LITTLE COLDER THAN INITIAL GUIDANCE TO ACCOUNT FOR THE ARCTIC HIGHS THAT WILL BE OVER NORTHEASTERN MINNESOTA IN THE LONG TERM. HIGHS IN THE MID TEENS TO MID 20S ON SATURDAY...THEN THE SINGLE DIGITS ON SUNDAY AND MONDAY BEFORE RECOVERING TO THE TEENS TUESDAY. LOWS NEAR ZERO TO TEN OR MORE BELOW ZERO ON THURSDAY NIGHT...MILD FRIDAY NIGHT DUE TO WEAK SOUTHERLY WINDS...THEN 0 TO -15 SATURDAY NIGHT AND 10 TO 20 BELOW ZERO ON SUNDAY NIGHT. MONDAY MORNING WILL BE THE COLDEST PERIOD IN THE LONG TERM WITH WIND CHILL VALUES OF 25 TO 35 BELOW ZERO...AND COLD SPOTS IN THE TIP OF THE ARROWHEAD REGION NEAR 40 BELOW ZERO. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1158 AM CST WED JAN 28 2015 IFR/LIFR CIGS AND MVFR/IFR VSBYS WERE FOUND ACROSS THE AREA LATE THIS MORNING...AND THAT TREND SHOULD CONTINUE INTO THIS AFTERNOON AT ALL TERMINALS. AREAS OF LIGHT SNOW/FREEZING DRIZZLE/FREEZING FOG HAVE BEEN REPORTED OVER NORTHWEST MINNESOTA AND PORTIONS OF NORTHWESTERN ONTARIO...AND EXPECT PRECIPITATION TO MOVE INTO INL LATER THIS AFTERNOON. CONFIDENCE IN PRECIPITATION TYPE IS LOW...BUT IT SEEMS FREEZING DRIZZLE/FREEZING FOG ARE MORE LIKELY THAN LIGHT SNOW WITH THIS PACKAGE. AS DEEPER SATURATION EXPANDS ACROSS REMAINING MN AIRPORTS THIS AFTERNOON...INTRODUCED A MIX OF FREEZING DRIZZLE/LIGHT SNOW BEFORE 29.00Z. THE PRECIPITATION WILL BE SLOWEST TO ARRIVE AT HAYWARD...WHERE ONSET SHOULD BE DELAYED UNTIL THIS EVENING. FOCUS THEN SHIFTS TO AN APPROACHING COLD FRONT LATER OVERNIGHT AND COLD AIR POURING INTO THE AREA ON THURSDAY. WINDS WILL VEER NORTHWEST THIS EVENING...BUT THE INCREASE IN SPEEDS WILL BE DELAYED UNTIL LATE OVERNIGHT/EARLY THURSDAY MORNING. TEMPERATURES WILL COOL SUFFICIENTLY TO SWITCH PRECIPITATION TO ALL SNOW AND THE STRONG WINDS WILL RESULT IN MVFR VSBYS. && .PRELIMINARY POINT TEMPS/POPS... DLH 31 24 24 -1 / 10 50 10 0 INL 31 16 16 -10 / 10 60 10 0 BRD 34 22 22 5 / 10 40 0 0 HYR 32 27 28 -2 / 10 50 20 0 ASX 34 27 29 2 / 10 50 20 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...DAP SHORT TERM...GSF LONG TERM...JJM AVIATION...HUYCK
AREA FORECAST DISCUSSION
NWS DULUTH MN
1132 AM CST WED JAN 28 2015 .UPDATE... ISSUED AT 1123 AM CST WED JAN 28 2015 LATE THIS MORNING...PERSISTENT LOW CLOUDS WERE FOUND ACROSS THE NORTHLAND. HAVE NOT BEEN ABLE TO FIND ANY REPORTS OF LOCAL FREEZING DRIZZLE OR OR SNOW AS OF 11 AM. WILL HOLD OFF MENTIONING FZDZ FOR ANY OF THE DAYTIME HOURS...BUT WILL ADD SOME TO THE SOUTHERN CWA THIS EVENING FOR A TIME. UPDATE ISSUED AT 654 AM CST WED JAN 28 2015 ADDED SOME PATCHY FOG THIS MORNING AS SEVERAL LOCATIONS ARE REPORTING. SHOULD SEE THE FOG LIFT BY 15Z. REST OF THE FORECAST ON TRACK. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 353 AM CST WED JAN 28 2015 LOW PRESSURE WAS ORGANIZING IN THE DAKOTAS AT 08Z WITH A FRONTAL BOUNDARY EXTENDING NORTHEASTWARD INTO SOUTHERN MANITOBA AND INTO NW ONTARIO. IN THE WAA AHEAD OF THIS SYSTEM...SOME LIGHT SNOW WAS FALLING OVER THE ARROWHEAD WITH LITTLE ACCUMULATION. NORTH OF THE CANADIAN BORDER...SOME LIGHT FREEZING RAIN WAS OCCURRING RIGHT NEAR THE FRONT FROM WINNIPEG TO NEAR DRYDEN. LATEST SHORT TERM HRRR AND RAP KEEP THIS FREEZING RAIN NORTH OF THE BORDER. THE LIGHT SNOW OVER THE ARROWHEAD IS EXPECTED TO SLOWLY END BY NOON. LITTLE ADDITIONAL ACCUMULATION IS ANTICIPATED. BY THIS AFTERNOON...THE SFC LOW MOVES EASTWARD WITH THE LOW CENTER BEGINS TO REORGANIZE AND DRIFT INTO SOUTHWEST IOWA BY 00Z THURSDAY. MEANWHILE...A MID LEVEL LONG WAVE TROF MOVES OVER THE WESTERN GREAT LAKES. SOME MODEL DIFFERENCES BEGIN TO REVEL THEMSELVES WITH RESPECT TO QPF PLACEMENT AND THE AMOUNT OF COLD AIR FORECAST TO DROP INTO THE FORECAST AREA. THE GFS IS THE MOST ROBUST AND FURTHEST SOUTH WHILE THE ECMWF HAS LIMITED QPF AND KEEPS IT NEAR THE CANADIAN BORDER. HAVE USED A BLENDED APPROACH AND KEPT POPS TO THE NORTHERN HALF OF THE FORECAST AREA BY LATE AFTERNOON. PRECIPITATION TYPE WILL BE ALL SNOW. LATEST FORECAST SOUNDINGS ARE NOT SUPPORTING THE MENTION OF FREEZING RAIN OR FREEZING DRIZZLE AND HAVE REMOVED. TONIGHT...THE MID LEVEL LONG WAVE TROF MOVES EAST OF THE FORECAST AREA BY 12Z THURSDAY. THIS PUSHES THE SFC LOW EAST OF THE AREA AS WELL. BEHIND THIS SYSTEM...A TIGHTENING PRESSURE GRADIENT MOVES OVER THE WESTERN GREAT LAKES AS HIGH PRESSURE BUILDS INTO THE WESTERN DAKOTAS. MADE SOME MINOR CHANGES TO THE POPS AND THEIR TIMING ACROSS THE AREA...WITH THE SNOW ENDING LATE TONIGHT OVER THE SOUTHWEST PORTION OF THE FORECAST AREA TO THE TWIN PORTS LATE TONIGHT. FORECAST SOUNDINGS INDICATE THAT THE PRECIPITATION TYPE WILL BE ALL SNOW AND HAVE REMOVED THE MENTION FREEZING RAIN/FREEZING DRIZZLE AND SLEET. SNOW AMOUNTS WILL BE LIGHT WITH THE HIGHEST AMOUNTS OF AROUND ONE HALF INCH FOUND ALONG THE CANADIAN BORDER. ON THURSDAY...ONLY MADE SOME MINOR CHANGES TO THE POPS AND WEATHER AS MODELS ARE IN VERY GOOD AGREEMENT. WILL STILL HAVE GUSTY WINDS AS THE TIGHT PRESSURE GRADIENT REMAINS UNTIL LATE AFTERNOON WHEN THE AFOREMENTIONED HIGH PRESSURE MOVES INTO THE RED RIVER VALLEY. A NW WIND OVER LAKE SUPERIOR AND CAA WILL LEAD TO SOME LAKE EFFECT SNOW ALONG THE HIGHER TERRAIN OF THE SOUTH SHORE. SNOW AMOUNTS WILL BE LIGHT HOWEVER AS DEEP COLD AIR IS LACKING UNTIL LATE AFTERNOON. .LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY) ISSUED AT 353 AM CST WED JAN 28 2015 MUCH COLDER AIR ON THE WAY FOR THIS WEEKEND WITH A CHANCE FOR SNOW FROM...YOU GUESSED IT...ANOTHER WEAK CLIPPER SYSTEM. THE LARGE SCALE PATTERN WILL UNDERGO SOME CHANGES THROUGH THE LONG TERM THAT WILL /AT LEAST TEMPORARILY/ PUT A STOP TO WHAT HAS BEEN A LONG PERIOD OF WEAK /AND FRANKLY DISAPPOINTING FOR SNOW LOVERS/ CLIPPERS. TEMPERATURES WILL DROP FROM WHAT HAS BEEN A VERY MILD PATTERN TO A COLDER REGIME...ENDING THE LAST WEEK OF JANUARY WITH TEMPS SIMILAR TO THE FIRST WEEK OF THE MONTH. ON THE SYNOPTIC SCALE A SERIES OF STRONG ARCTIC AIR MASSES WILL DROP DOWN INTO THE NORTHERN PLAINS AND UPPER MIDWEST. LATE THIS WEEK AN AREA OF HIGH PRESSURE WILL MOVE OVER THE AREA THURSDAY NIGHT FOLLOWED BY A WEAK CLIPPER ON FRIDAY/FRIDAY NIGHT. THEN LATE IN THE WEEKEND A DEEP LONGWAVE TROUGH AT MID-LEVELS WILL DESCEND OVER THE MIDWEST LEADING TO VERY COLD AIR ALOFT...850MB TEMPS APPROACHING THE COLDEST 10 PERCENT OF CLIMATOLOGY IN THE MID -20S C /COMPARED TO 00Z TODAY WHEN THEY WERE IN THE WARMEST 10 PERCENT OF CLIMO AT AROUND 0C/. BEST CHANCE FOR SNOWFALL ACROSS THE REGION WILL BE LATE FRIDAY AFTERNOON INTO FRIDAY NIGHT A CLIPPER MOVES ACROSS. GFS AND ECMWF IN GOOD AGREEMENT ON TIMING...WITH ECMWF PESSIMISTIC ON INTENSITY AND GFS A LITTLE STRONGER WITH A DEEPER MOISTURE PROFILE. GEM WAS SLOWER AND NOT AS INTENSE OVERALL...BUT THIS WAS A PRETTY BIG CHANGE FROM 12Z GEM WHICH WAS FASTER AND MUCH MORE AGGRESSIVE ON PRECIP. AT THIS POINT IT LOOKS LIKE A QUICK INCH OR TWO FOR NORTHERN MINNESOTA NORTH OF HIGHWAY TWO. OTHERWISE NO SIGNIFICANT CHANCES FOR PRECIP IN THE SEVEN DAY FOR MUCH OF THE REGION...WITH THE EXCEPTION OF LAKE EFFECT SNOWFALL ALONG PORTIONS OF THE SOUTH SHORE OF LAKE SUPERIOR. LAKE EFFECT SNOWFALL WILL BE PRESENT THROUGH MUCH OF THE LONG TERM PERIOD. ON THURSDAY NIGHT CONDITIONS WILL BE GOOD FOR LAKE EFFECT SNOWFALL ALONG THE HIGHER TERRAIN OF IRON/ASHLAND COUNTIES WITH STEEP LOW LEVEL LAPSE RATES THROUGH 850MB AND GREAT NORTH/NORTHWEST FLOW OVER THE LAKE. ICE COVERAGE ON THE SOUTH SHORE MAY LIMIT THE INTENSITY OF LAKE EFFECT SNOWFALL...AND OPTED TO LEAVE NORTHERN BAYFIELD COUNTY OUT OF HIGHER CHANCES FOR LAKE EFFECT SNOWFALL DUE TO WHAT WOULD BE A VERY LIMITED FETCH LENGTH. LOW LEVEL MOISTURE WILL ALSO BE A FACTOR AS NAM/GFS/ECMWF DEPICT A NEAR-SURFACE DRY LAYER...SO IT MAY TAKE A WHILE TO SATURATE LOW LEVELS AND THUS LIMIT SNOWFALL AMOUNTS. LAKE EFFECT WILL TAPER OFF AS HIGH PRESSURE MOVES OVER LAKE SUPERIOR ON FRIDAY AFTERNOON...BUT RAMP BACK UP AGAIN ON SATURDAY AND THROUGH ABOUT TUESDAY DUE TO THE VERY COLD AIRMASS THAT WILL BE IN PLACE. TEMPS WILL BE ON A DOWNWARD TREND...AND HAVE ADJUSTED SOME OF THE USUAL COLD SPOTS A LITTLE COLDER THAN INITIAL GUIDANCE TO ACCOUNT FOR THE ARCTIC HIGHS THAT WILL BE OVER NORTHEASTERN MINNESOTA IN THE LONG TERM. HIGHS IN THE MID TEENS TO MID 20S ON SATURDAY...THEN THE SINGLE DIGITS ON SUNDAY AND MONDAY BEFORE RECOVERING TO THE TEENS TUESDAY. LOWS NEAR ZERO TO TEN OR MORE BELOW ZERO ON THURSDAY NIGHT...MILD FRIDAY NIGHT DUE TO WEAK SOUTHERLY WINDS...THEN 0 TO -15 SATURDAY NIGHT AND 10 TO 20 BELOW ZERO ON SUNDAY NIGHT. MONDAY MORNING WILL BE THE COLDEST PERIOD IN THE LONG TERM WITH WIND CHILL VALUES OF 25 TO 35 BELOW ZERO...AND COLD SPOTS IN THE TIP OF THE ARROWHEAD REGION NEAR 40 BELOW ZERO. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 526 AM CST WED JAN 28 2015 GENERALLY IFR CONDITIONS THROUGH MOST OF THE TAF PERIOD AT ALL SITES DUE TO LOW CEILINGS AND PATCHY FOG DEVELOPING. AS OF THIS MORNING ALL TAF SITES EXCEPT FOR INL WERE ALREADY AT IFR CONDITIONS...WITH INL CEILINGS EXPECTED TO WORSEN LATER THIS MORNING. THERE WILL BE LITTLE IMPROVEMENT THROUGH THE DAY WITH SOME SITES POSSIBLY DETERIORATING TO LIFR CEILINGS AND IFR VISIBILITY THIS AFTERNOON. TONIGHT A COLD FRONT WILL MOVE THROUGH WHICH WILL IMPROVE CONDITIONS...WITH CEILINGS IMPROVING TO MVFR LEVELS. WINDS WILL BE LIGHT TODAY OUT OF THE SOUTH...BUT BEHIND THE COLD FRONT LATE TONIGHT WINDS WILL RAPIDLY INCREASE TO BECOME 10 TO 15 KTS OUT OF THE WEST WITH GUSTS APPROACHING/EXCEEDING 30 KTS AT TIMES. DID NOT INCLUDE STRONG WINDS IN ALL TAFS SINCE TIMING WILL BE RIGHT AROUND END OF THE TAF PERIOD. && .PRELIMINARY POINT TEMPS/POPS... DLH 31 24 24 -1 / 10 50 10 0 INL 31 16 16 -10 / 10 60 10 0 BRD 34 22 22 5 / 10 40 0 0 HYR 32 27 28 -2 / 10 50 20 0 ASX 34 27 29 2 / 10 50 20 20 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...NONE. && $$ UPDATE...DAP SHORT TERM...GSF LONG TERM...JJM AVIATION...JJM
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1100 AM CST WED JAN 28 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 344 AM CST WED JAN 28 2015 BEEN ANOTHER QUIET NIGHT ACROSS THE AREA...THANKS TO AN UPPER LEVEL SHORTWAVE RIDGE AXIS THAT HAS BEEN STEADILY MAKING ITS WAY EAST THROUGH THE PLAINS...PUSHED BY AN UPPER LEVEL DISTURBANCE MOVING INTO WRN PORTIONS OF WY. AT THE SURFACE...THE PATTERN OVER THE CWA IS ONCE AGAIN ON THE WEAKER SIDE...WITH A TROUGH AXIS SET UP OVER THE HIGH PLAINS...RESULTING IN LIGHT AND AT TIMES VARIABLE WINDS. TEMPS EARLY THIS MORNING AT 3 AM RANGE ANYWHERE FROM THE MID 20S IN THE NORTH TO MID 40S IN THE FAR SWRN CORNER OF THE CWA. THE MAIN STORY THROUGH THE SHORT TERM PERIOD LIES WITH THAT UPPER LEVEL DISTURBANCE PUSHING INTO WY THIS MORNING...AND THE ACCOMPANYING FRONTAL BOUNDARY IT WILL PUSH THROUGH THE CWA. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE TIMING OF THIS DISTURBANCE...SHOWING IT MOVING INTO THE NEB PANHANDLE NEAR MIDDAY TODAY...BY 00Z THIS EVENING THE TROUGH AXIS LOOKS TO BE EXTENDING THROUGH THE HEART OF THE CWA...BEFORE PUSHING OFF TO THE MISSOURI RIVER AREA BY MIDNIGHT TONIGHT. A WEAKER SECOND MID LEVEL DISTURBANCE QUICK ON THE HEELS OF THE MAIN ONE IS FORECAST TO BE WORKING INTO THE AREA AS WE GET INTO THE EARLY MORNING HOURS THURSDAY. EVEN WITH THERE ACTUALLY BEING A SYSTEM TO TALK ABOUT...MODELS /INCLUDING THE MORE SHORT TERM HIRES LIKE THE WRF/ OVERALL CONTINUE TO BE IN GOOD AGREEMENT SHOWING CONDITIONS REMAINING DRY...JUST NOT A LOT OF MOISTURE TO WORK WITH. THAT BEING SAID...SOME MODELS ARE HINTING AT THE POTENTIAL OF SOME VERY LIGHT PRECIP FALLING THIS EVENING/OVERNIGHT...BUT KEEP THAT SIGNAL JUST OUTSIDE THE N/NERN BORDERS OF THE CWA. WILL BE SOMETHING FOR THE DAY SHIFT TO MONITOR WITH THE 12Z RUN OF MODELS THIS MORNING. AT THE SFC...WINDS WILL REMAIN ON THE LIGHTER SIDE THIS MORNING...BEFORE THE WIND SHIFT OF THE COLD FRONT ACCOMPANYING THIS SYSTEM PASSES THROUGH THE CWA...WHICH MODELS SHOW PUSHING ABOUT HALFWAY THROUGH THE CWA BY MID MORNING AND MAKING IT TO THE ERN FRINGE OF THE CWA AROUND MIDDAY. THIS WILL USHER IN A PUSH OF GUSTY W/NWRLY WINDS /15 TO 25 MPH IS FORECAST/...BUT THE MAIN PUSH OF COLDER AIR IS LAGGING BEHIND. TEMPS ALOFT COOL A TOUCH DURING THE DAY...BUT HIGHS ARE STILL FORECAST TO BE WELL ABOVE AVERAGE...THANKS TO THE MILD AIR/DOWNSLOPING WINDS. NOT EXPECTED TO BE AS WARM AS TUESDAY...BUT TRENDED HIGHS TOWARD THE MAV AND RAP /WHICH DID PRETTY WELL TUESDAY/...WHICH PUTS THE MAJORITY OF THE CWA AT LEAST INTO THE MID 60S /THE EXCEPTION AGAIN IS THE E/NERN PORTIONS/...WITH HIGHS NEAR 70 FORECAST IN NC KS. IF TEMPS PAN OUT AS FORECAST...IT WOULD SET A NEW RECORD HIGH TEMPS IN GRAND ISLAND. BUT CONFIDENCE ISNT THE HIGHEST...AS THERE ARE MODELS THAT SAY IT WILL FALL SHORT OF/MAYBE TIE THE RECORD OF 63 DEGREES. THE RECORD AT HASTINGS IS 69 DEGREES...AND THE RAP IS BASICALLY THE ONLY ONE SHOWING THE POTENTIAL FOR TEMPS TO MAKE A RUN AT THAT RECORD. FIRE WX CONCERNS ARISE AGAIN...SEE FIRE WEATHER SECTION BELOW FOR ADDITIONAL INFORMATION. THIS EVENING/TONIGHT...ONE MIGHT THINK THAT WINDS WE HAVE THIS AFTERNOON WOULD TAPER OFF...BUT WITH THE MAIN PUSH OF COLD AIR ADVECTION...BETTER PRESSURE RISES/TIGHTER PRESSURE GRADIENT...AND STRONGER WINDS ALOFT TO TAP INTO...THATS NOT THE CASE. MADE SOME ADJUSTMENTS TO WIND SPEEDS...WHICH WILL BE ON A SECOND INCREASE THIS EVENING...AND BY MIDNIGHT TONIGHT SPEEDS IN THE 25 TO 30 MPH RANGE WILL BE POSSIBLE...MAINLY ACROSS OUR SC NEB COUNTIES. LOOKS TO REMAIN BREEZY INTO THE EARLY MORNING HOURS THURSDAY. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 344 AM CST WED JAN 28 2015 GUIDANCE SUGGESTS AN UPPER TROPOSPHERIC SHORT WAVE WILL BE NOTED OVER THE MID-MISSISSIPPI VALLEY TO START THE LONG-TERM FORECAST PERIOD AT 12Z THURSDAY...THUS HELPING PROVIDE NORTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA. THIS NORTHWESTERLY FLOW IS EXPECTED TO PERSIST OVER OUR AREA THURSDAY INTO THURSDAY NIGHT BEFORE THE APPROACH OF AN UPPER TROPOSPHERIC LONGWAVE TROUGH AXIS PROMOTES QUASI-ZONAL TO SOUTHWESTERLY UPPER TROPOSPHERIC FLOW FRIDAY THROUGH SATURDAY. THIS UPPER TROPOSPHERIC TROUGH AXIS IS EXPECTED TO CLEAR OUR AREA SATURDAY NIGHT...THUS ALLOWING FOR NORTHWESTERLY UPPER TROPOSPHERIC FLOW OVER OUR AREA AS WE HEAD INTO THE EARLY PART OF NEXT WEEK. GUIDANCE SUGGESTS AN OVERALL LACK IN OMEGA WILL KEEP US DRY THURSDAY...THURSDAY NIGHT AND THROUGH THE DAY FRIDAY...AND SUCH HAS BEEN PRESENTED IN THE OFFICIAL FORECAST. STARTING FRIDAY NIGHT AND CONTINUING INTO SATURDAY...SATURDAY NIGHT AND PERHAPS EARLY SUNDAY...UPPER TROPOSPHERIC THERMAL ADVECTION AHEAD OF THE APPROACHING TROUGH AXIS IS EXPECTED TO PROMOTE ENOUGH OMEGA FOR PRECIPITATION PRODUCTION ACROSS MUCH OF THE REGION...INCLUDING OUR CWA. THE OPERATIONAL GFS AND EC CONTINUE TO COME INTO BETTER AGREEMENT BY SUGGESTING PRECIPITATION WILL MOVE IN FROM SOUTHWEST TO NORTHEAST ACROSS MUCH OF OUR AREA...AGAIN BEGINNING FRIDAY NIGHT...WITH WIDESPREAD PRECIPITATION THEN CONTINUING ACROSS THE AREA SATURDAY AND SATURDAY NIGHT BEFORE MOVING EAST...ALONG THE UPPER TROPOSPHERIC TROUGH AXIS...AROUND OR SHORTLY AFTER SUNRISE SUNDAY. INTERESTING TO NOTE THAT THE NAM...WHICH THROUGH 84 HOURS IS JUST NOW UP TO 12Z SATURDAY...APPEARS TO KEEP THE PRIMARY AXIS OF OMEGA WELL TO OUR SOUTHEAST AND AS A RESULT...KEEPS US DRY THROUGH 12Z SATURDAY. ALTHOUGH IT WILL BE VERY INTERESTING TO SEE HOW THE NAM UNFOLDS THROUGH THE NEXT FEW RUNS...GIVEN THE AFOREMENTIONED DATA FROM THE OPERATIONAL GFS AND EC...IT SEEMS PRUDENT TO PRESENT YET ANOTHER INCREASE IN POPS FOR THIS WEEKEND AND 30-60% POPS ARE NOW SHOWN IN THE OFFICIAL FORECAST...WITH THE HIGHEST POPS RELEGATED TO OUR SOUTHEAST WHICH IS WHERE GUIDANCE SUGGESTS THE STRONGEST OMEGA AND MOST EFFICIENT PRECIPITATION PRODUCTION WILL RESIDE DURING THIS UPCOMING STORM SYSTEM. ONCE PRECIPITATION COMES TO AN END ON SUNDAY...GUIDANCE SUGGESTS DRY CONDITIONS SHOULD BE OBSERVED SUNDAY NIGHT THROUGH TUESDAY...AND SUCH HAS BEEN PRESENTED IN THE OFFICIAL FORECAST. ALTHOUGH IT APPEARS PRECIPITATION COULD START OUT AS RAIN FRIDAY NIGHT...FORECAST PROXIMITY SOUNDINGS FROM ACROSS THE CWA...PER THE OPERATIONAL GFS AND EC...SUGGEST THE LOWER TROPOSPHERE WILL BE SUPPORTIVE FOR SNOWFALL AT THE SURFACE BY 12Z SATURDAY AND CONTINUING INTO SUNDAY. THAT SAID...WITH A CONTINUED SOUTH/SOUTHEASTERLY BOUNDARY- LAYER WIND FIELD EXPECTED THROUGH THE DAY SATURDAY...THERE IS STILL AT LEAST AN OPPORTUNITY FOR SOME TEMPERATURE RECOVERY NEAR THE SURFACE DURING THE DAY SATURDAY AND SUPERBLEND RESPONDED BY PROVIDING SATURDAY HIGHS IN THE UPPER 30S AND LOW 40S. THERE ARE SUGGESTIONS FROM MULTIPLE SETS OF GUIDANCE THAT THIS TEMPERATURE FORECAST FOR SATURDAY IS TOO HIGH AND NEEDS TO BE REDUCED BY 4-5 DEGREES. WENT AHEAD WITH A ~2 DEGREE DECREASE FROM THE SUPERBLEND SOLUTION FOR SATURDAY HIGHS TO ACCOUNT OF THIS...BUT EVEN NOW THE OFFICIAL FORECAST CALLS FOR SATURDAY TEMPERATURE READINGS IN THE UPPER 30S FOR MOST LOCATIONS AND GIVEN THIS...DESPITE FORECAST PROXIMITY SOUNDINGS FROM THE OPERATIONAL GFS AND EC SUGGESTING SNOWFALL WILL BE THE PRIMARY PRECIPITATION TYPE DURING THE DAY SATURDAY...FIND IT HARD TO JUSTIFY AN ALL-SNOW FORECAST WITH SURFACE TEMPERATURE READINGS SO HIGH. AS A RESULT...OPTED TO GO WITH A RAIN AND SNOW MIX DURING THE DAY SATURDAY...WITH ALL SNOW THEN EXPECTED SATURDAY NIGHT INTO SUNDAY AS DIABATIC HEATING IS LOST AND A BOUNDARY-LAYER BAROCLINIC ZONE CLEARS THE AREA. OBVIOUSLY THE TEMPERATURE FORECAST FOR SATURDAY WILL NEED TO BE CLOSELY MONITORED AS ANY MORE OF A DECREASE IN SATURDAYS TEMPERATURE FORECAST WOULD SUGGEST MORE SNOW THAN RAIN DURING THE DAY SATURDAY...AND MORE IN THE WAY OF SNOW ACCUMULATION. OBVIOUSLY STORM-TOTAL SNOWFALL ACCUMULATION WILL BE HEAVILY DEPENDENT UPON HOW MUCH SNOWFALL IS REALIZED DURING THE DAY SATURDAY...AND GIVEN THE UNCERTAINTY WITH RESPECT TO PRECIPITATION TYPE AND RESULTANT SNOW ACCUMULATION DURING THE DAY SATURDAY...IT STILL REMAINS TOO EARLY TO GET SPECIFIC ON SNOW AMOUNTS IN THE OFFICIAL FORECAST. THAT SAID...ONCE AGAIN TAKING THE OPERATIONAL GFS AND EC AT FACE VALUE SUGGESTS ADVISORY-WORTHY ACCUMULATION OF ~3 INCHES COULD BE REALIZED ACROSS PORTIONS OF THE CWA SATURDAY NIGHT INTO EARLY SUNDAY MORNING ALONE...DESPITE WHAT HAPPENS DURING THE DAY SATURDAY. IN ADDITION...GUIDANCE IS NOW SUGGESTING THAT AN INCREASING PRESSURE GRADIENT POST-FROPA SATURDAY NIGHT INTO SUNDAY WILL PROMOTE A STRONG WIND...SUSTAINED AT AROUND 18KTS WITH HIGHER GUSTS. THIS WIND...WORKING IN CONCERT WITH THE SNOWFALL...WOULD LIKELY CREATE AT LEAST PERIODIC VISIBILITY RESTRICTION IN BLOWING SNOW. SO...GIVEN THE FACT THAT WE NOW HAVE "LIKELY" POPS IN THE FORECAST FOR PORTIONS OF THE AREA THIS WEEKEND...AND THE FACT THAT IT NOW APPEARS WE HAVE AN OPPORTUNITY FOR BLOWING SNOW AND VISIBILITY RESTRICTION...FEEL IT PRUDENT TO INTRODUCE A MENTION OF ACCUMULATING SNOWFALL AND VISIBILITY RESTRICTION DUE TO BLOWING SNOW FOR THIS WEEKEND IN THE HWO. FINALLY...HIGHS TO START THE LONG-TERM FORECAST PERIOD ON THURSDAY AND FRIDAY ARE STILL EXPECTED TO CLIMB INTO THE 40S...BUT WILL FALL INTO THE 20S POST-FROPA STARTING EARLY NEXT WEEK. OVERNIGHT LOWS IN THE 20S AND 30S ARE ALSO EXPECTED TO START THE LONG-TERM FORECAST PERIOD...BUT THESE READINGS WILL LIKELY FALL INTO THE SINGLE DIGITS AND TEENS EARLY NEXT WEEK AS WELL. && .AVIATION...(FOR THE 18Z KGRI/KEAR TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1056 AM CST WED JAN 28 2015 THE MAIN ISSUE FOR THE TAF PERIOD WILL BE INCREASING NORTHWEST WINDS. FOLLOWING THE PASSAGE OF A TROUGH AXIS THIS AFTN...NORTHWEST WINDS WILL MIX DOWN WITH WIND GUSTS AROUND 30 MPH POSSIBLE. EVEN STRONGER WINDS ARE FORECAST TONIGHT IN A TIGHTENING PRESSURE GRADIENT IN BETWEEN AN EXITING SFC LOW AND A BUILDING SFC RIDGE. NORTHWEST WIND GUSTS NEAR 40KTS ARE POSSIBLE THRU THE OVERNIGHT HOURS. WIND SPEEDS WILL SUBSIDE JUST BEYOND THE TAF PERIOD. CIGS MAY DROP TO MVFR. && .FIRE WEATHER... ISSUED AT 344 AM CST WED JAN 28 2015 GUSTY W/NW WINDS ARE EXPECTED TO DEVELOP ACROSS THE CWA DURING THE DAYTIME HOURS TODAY...AND ABOVE AVERAGE TEMPERATURES ARE ONCE AGAIN FORECAST. HIGH TEMPERATURES REACHING WELL INTO THE 60S TO NEAR 70 DEGREES IN SOME LOCATIONS...COMBINED WITH DEWPOINTS FORECAST TO FALL TO NEAR 30 DEGREES WILL RESULT IN NEAR CRITICAL FIRE WEATHER CONDITIONS ACROSS PORTIONS OF THE CWA. THE BEST CHANCE FOR RELATIVE HUMIDITY VALUES TO FALL INTO THE 20 TO 25 MPH RANGE WITH THOSE GUSTY WINDS WILL LIE ACROSS AREAS GENERALLY ALONG AND WEST OF A LEXINGTON NEB TO BELOIT KS LINE. && .CLIMATE... ISSUED AT 331 AM CST TUE JAN 27 2015 YET ANOTHER DAY WITH FORECAST HIGHS WELL ABOVE AVERAGE IS EXPECTED TODAY. AVERAGE HIGHS FOR THIS TIME OF YEAR ARE MAINLY IN THE MID 30S...WITH HIGHS FORECAST TODAY TO REACH INTO THE 60S /NEAR 70 POSSIBLE ACROSS SRN LOCATIONS/. HERE IS THE RECORD HIGH TEMPERATURE INFORMATION FOR TODAY...WITH GRAND ISLAND CURRENTLY FORECAST TO BREAK THAT RECORD...BUT HASTINGS FORECAST TO FALL A BIT SHORT. GRAND ISLAND: RECORD IS 63 DEGREES IN 1986. FORECAST HIGH: 65 HASTINGS: RECORD IS 69 DEGREES IN 1931. FORECAST HIGH: 65 && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...ADP LONG TERM...BRYANT AVIATION...FAY FIRE WEATHER...ADP CLIMATE...ADP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1237 PM CST WED JAN 28 2015 .UPDATE... ISSUED AT 1227 PM CST WED JAN 28 2015 ALLOWED THE DENSE FOG ADVISORY TO EXPIRE ACROSS THE NORTH AND EAST AS VISIBILITIES HAVE CONSISTENTLY IMPROVED. HAVE LEFT AREAS OF FOG IN THE FORECAST FOR PORTIONS OF THE NORTH CENTRAL AND JAMES RIVER VALLEY...WITH PATCHY MENTIONS CENTRAL AND NORTHWEST. INCREASED WINDS A BIT IN THE SOUTHWEST...BUT FOR NOW WILL HOLD OFF ON ANY WIND ADVISORY AS CRITERIA IS BORDERLINE AND THE HIGHEST WIND SPEEDS DO NOT LAST ALL THAT LONG. UPDATE ISSUED AT 1018 AM CST WED JAN 28 2015 UPDATED THE FORECAST FOR PATCHY FREEZING DRIZZLE ACROSS THE NORTH THROUGH 00 UTC. PROFILES SHOW A SATURATED LOWER LEVEL AND WITH MOST OF THE MORNING AND AFTERNOON BELOW FREEZING ACROSS THE NORTH DO EXPECT TO SEE SOME LIGHT FREEZING DRIZZLE. UPDATE ISSUED AT 630 AM CST WED JAN 28 2015 NO UPDATES OTHER THAN TO UPDATE TEMPERATURES BASED ON LATEST 6 AM OBSERVATIONS. UPDATE ISSUED AT 546 AM CST WED JAN 28 2015 BASED ON TRENDS VIA OBSERVATIONS AND SATELLITE IMAGERY...WILL LEAN ON HRRR GUIDANCE (WHICH IS DOING VERY WELL) AND EXPAND FOG WORDING WEST AND SOUTH AND WILL ALSO EXPAND THE DENSE FOG ADVISORY FARTHER WEST. ALSO EXTENDED TILL 18Z FOR HEADLINE CUTOFF. UPDATE ISSUED AT 344 AM CST WED JAN 28 2015 WILL GO WITH A DENSE FOG ADVISORY EAST. OBSERVATIONS NOT GETTING ANY BETTER AND AREA WEB CAMS SHOWING WORSE VISIBILITIES NOW. UPDATED PRODUCTS OUT SOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CST WED JAN 28 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE COOLER TEMPERATURES...BREEZY CONDITIONS...AND CHANCES FOR LIGHT SNOW TODAY AND TONIGHT. CURRENTLY...ZONAL FLOW ALOFT WITH THE UPPER LEVEL RIDGE FLATTENING ACROSS THE GREAT PLAINS IN RESPONSE TO SOUTHERN AND NORTHERN STREAM S/WV`S CROSSING THE ROCKIES. SURFACE LOW PRESSURE ASSOCIATED WITH THE SOUTHERN STREAM WAVE MOVING SOUTHEAST ACROSS SOUTHWEST NORTH DAKOTA INTO CENTRAL SOUTH DAKOTA. SOUTH/SOUTHEASTERLY RETURN FLOW AHEAD OF THE LOW HAS MAINTAINED LOW STRATUS AND/OR FOG ACROSS EASTERN NORTH DAKOTA SINCE YESTERDAY EVENING. LARGE STRATUS FIELD WRAPS BACK WESTWARD ACROSS SOUTH CENTRAL CANADA WITH THE SOUTHERN EDGE OF THE STRATUS ALONG TO SLIGHTLY NORTH OF THE INTERNATIONAL BORDER. VISIBILITIES CONTINUE TO FLUCTUATE ACROSS MY EAST...AND WILL HANDLE THE PATCHY DENSE FOG WITH THE CURRENT SPECIAL WEATHER STATEMENT. AS THE SURFACE LOW CONTINUES SOUTHEAST TODAY...SURFACE WINDS BECOME MORE NORTHWESTERLY AND INCREASE THROUGH THE MORNING INTO THE AFTERNOON BEHIND A STRONG SFC COLD FRONT. BUFKIT ANALYSIS BRINGS 35 TO NEAR 40KTS WITHIN THE TOP OF THE MIXED LAYER TO MOST SITES...SO WHILE BREEZY...SUB-ADVISORY MAGNITUDES. THUS NO HEADLINES WITH THIS FORECAST ISSUANCE. STRATUS TO OUR NORTH SURGES SOUTH ALONG WITH CAA WITH MOST OF REGION CLOUDED OVER BY EARLY TO MID AFTERNOON. CLOUD COVER AND BREEZY CONDITIONS WILL THEN CONTINUE INTO WEDNESDAY NIGHT. POST FRONTAL SNOW SHOWERS DEVELOP LATER THIS MORNING NORTH THEN SOUTHWARD THIS AFTERNOON CONTINUING TONIGHT. KEPT POPS AT SLIGHT CHANCE FOR NOW...BUT MAY NEED TO BE INCREASED. FOR TEMPERATURES...DESPITE CAA AND CLOUD COVER...THE INCREASED MIXING WITH THE BREEZY NORTHWEST WIND WILL ACTUALLY KEEP TEMPERATURES FROM BOTTOMING OUT TOO MUCH TODAY. DAYTIME HIGHS WILL BE COOLER THAN TUESDAY...RANGING FROM THE LOW 30S NORTH TO MID/UPPER 40S SOUTHWEST. SO ABOUT 5-15 DEGREES COOLER. CLOUD COVER AND CONTINUED MIXING TONIGHT SHOULD ALSO KEEP LOWS FROM DROPPING TOO MUCH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 315 AM CST WED JAN 28 2015 CHANCES FOR SNOW SATURDAY AND COOLER TEMPERATURES THROUGH THE WEEKEND AND INTO NEXT WEEK WILL HIGHLIGHT THE LONG TERM. AN UPPER LEVEL TROUGH MOVING SOUTHEAST FROM ALBERTA LATE FRIDAY INTO EARLY SATURDAY MORNING WILL BRING A CHANCE OF SNOW THROUGH SATURDAY NIGHT...ALONG WITH COLDER TEMPERATURES. THERE IS GOOD AGREEMENT BETWEEN THE GFS/ECMWF IN THE OVERALL TIMING/LOCATION OF THE UPPER LEVEL TROUGH. THE GLOBAL GEM IS AN OUTLIER AND WILL USE A GFS/EC SOLUTION. THIS BRINGS THE BEST CHANCES OF LIGHT SNOW ACCUMULATIONS MAINLY ALONG AND WEST OF THE HIGHWAY 83 CORRIDOR. SNOW GROWTH ZONE BECOMES RATHER DEEP BY 00 UTC SUNDAY BUT OMEGA WITHIN THE ZONE IS LIMITED. BUT WITH SNOW RATIOS INCREASING AS THE COLD AIR FILTERS IN...THINK ONE OR TWO INCH ACCUMULATIONS ARE POSSIBLE SATURDAY THROUGH SATURDAY NIGHT OVER THE WESTERN HALF OF NORTH DAKOTA. A NORTHEAST SURFACE FLOW OF 10 TO 20 MPH COULD YIELD SOME REDUCED VISIBILITIES IN FALLING SNOW...BUT SIGNIFICANT BLOWING AND DRIFTING IS NOT EXPECTED AT THIS TIME. THE REMAINDER OF THE FORECAST PERIOD BRINGS BELOW AVERAGE TEMPERATURES AND ONLY MINIMAL PRECIPITATION CHANCES AHEAD OF EACH REINFORCING SHOT OF COLD AIR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1227 PM CST WED JAN 28 2015 FOG AND CEILINGS HAVE IMPROVED AT SITES KISN...KMOT...AND KJMS AND ARE EXPECTED TO CONTINUE TO IMPROVE THROUGH THE AFTERNOON. HOWEVER...CONDITIONS ARE EXPECTED TO REMAIN LIFR TO IFR. FOR KBIS AND KDIK LOWER CEILINGS WILL MOVE IN THROUGH THE AFTERNOON FOR IFR CONDITIONS. TOOK OUT THE MENTION OF SNOW FROM TAFS AS PRECIP TYPE WILL MORE LIKELY BE FREEZING DRIZZLE OR SIMPLY DRIZZLE...HOWEVER IT WILL BE VERY LIGHT AND PATCHY ACROSS THE REGION THUS HAVE OPTED TO GO WITH BR IN THE TAFS. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...MM SHORT TERM...NH LONG TERM...TWH AVIATION...MM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1024 AM CST WED JAN 28 2015 .UPDATE... ISSUED AT 1018 AM CST WED JAN 28 2015 UPDATED THE FORECAST FOR PATCHY FREEZING DRIZZLE ACROSS THE NORTH THROUGH 00 UTC. PROFILES SHOW A SATURATED LOWER LEVEL AND WITH MOST OF THE MORNING AND AFTERNOON BELOW FREEZING ACROSS THE NORTH DO EXPECT TO SEE SOME LIGHT FREEZING DRIZZLE. UPDATE ISSUED AT 630 AM CST WED JAN 28 2015 NO UPDATES OTHER THAN TO UPDATE TEMPERATURES BASED ON LATEST 6 AM OBSERVATIONS. UPDATE ISSUED AT 546 AM CST WED JAN 28 2015 BASED ON TRENDS VIA OBSERVATIONS AND SATELLITE IMAGERY...WILL LEAN ON HRRR GUIDANCE (WHICH IS DOING VERY WELL) AND EXPAND FOG WORDING WEST AND SOUTH AND WILL ALSO EXPAND THE DENSE FOG ADVISORY FARTHER WEST. ALSO EXTENDED TILL 18Z FOR HEADLINE CUTOFF. UPDATE ISSUED AT 344 AM CST WED JAN 28 2015 WILL GO WITH A DENSE FOG ADVISORY EAST. OBSERVATIONS NOT GETTING ANY BETTER AND AREA WEB CAMS SHOWING WORSE VISIBILITIES NOW. UPDATED PRODUCTS OUT SOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 312 AM CST WED JAN 28 2015 FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE COOLER TEMPERATURES...BREEZY CONDITIONS...AND CHANCES FOR LIGHT SNOW TODAY AND TONIGHT. CURRENTLY...ZONAL FLOW ALOFT WITH THE UPPER LEVEL RIDGE FLATTENING ACROSS THE GREAT PLAINS IN RESPONSE TO SOUTHERN AND NORTHERN STREAM S/WV`S CROSSING THE ROCKIES. SURFACE LOW PRESSURE ASSOCIATED WITH THE SOUTHERN STREAM WAVE MOVING SOUTHEAST ACROSS SOUTHWEST NORTH DAKOTA INTO CENTRAL SOUTH DAKOTA. SOUTH/SOUTHEASTERLY RETURN FLOW AHEAD OF THE LOW HAS MAINTAINED LOW STRATUS AND/OR FOG ACROSS EASTERN NORTH DAKOTA SINCE YESTERDAY EVENING. LARGE STRATUS FIELD WRAPS BACK WESTWARD ACROSS SOUTH CENTRAL CANADA WITH THE SOUTHERN EDGE OF THE STRATUS ALONG TO SLIGHTLY NORTH OF THE INTERNATIONAL BORDER. VISIBILITIES CONTINUE TO FLUCTUATE ACROSS MY EAST...AND WILL HANDLE THE PATCHY DENSE FOG WITH THE CURRENT SPECIAL WEATHER STATEMENT. AS THE SURFACE LOW CONTINUES SOUTHEAST TODAY...SURFACE WINDS BECOME MORE NORTHWESTERLY AND INCREASE THROUGH THE MORNING INTO THE AFTERNOON BEHIND A STRONG SFC COLD FRONT. BUFKIT ANALYSIS BRINGS 35 TO NEAR 40KTS WITHIN THE TOP OF THE MIXED LAYER TO MOST SITES...SO WHILE BREEZY...SUB-ADVISORY MAGNITUDES. THUS NO HEADLINES WITH THIS FORECAST ISSUANCE. STRATUS TO OUR NORTH SURGES SOUTH ALONG WITH CAA WITH MOST OF REGION CLOUDED OVER BY EARLY TO MID AFTERNOON. CLOUD COVER AND BREEZY CONDITIONS WILL THEN CONTINUE INTO WEDNESDAY NIGHT. POST FRONTAL SNOW SHOWERS DEVELOP LATER THIS MORNING NORTH THEN SOUTHWARD THIS AFTERNOON CONTINUING TONIGHT. KEPT POPS AT SLIGHT CHANCE FOR NOW...BUT MAY NEED TO BE INCREASED. FOR TEMPERATURES...DESPITE CAA AND CLOUD COVER...THE INCREASED MIXING WITH THE BREEZY NORTHWEST WIND WILL ACTUALLY KEEP TEMPERATURES FROM BOTTOMING OUT TOO MUCH TODAY. DAYTIME HIGHS WILL BE COOLER THAN TUESDAY...RANGING FROM THE LOW 30S NORTH TO MID/UPPER 40S SOUTHWEST. SO ABOUT 5-15 DEGREES COOLER. CLOUD COVER AND CONTINUED MIXING TONIGHT SHOULD ALSO KEEP LOWS FROM DROPPING TOO MUCH. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 315 AM CST WED JAN 28 2015 CHANCES FOR SNOW SATURDAY AND COOLER TEMPERATURES THROUGH THE WEEKEND AND INTO NEXT WEEK WILL HIGHLIGHT THE LONG TERM. AN UPPER LEVEL TROUGH MOVING SOUTHEAST FROM ALBERTA LATE FRIDAY INTO EARLY SATURDAY MORNING WILL BRING A CHANCE OF SNOW THROUGH SATURDAY NIGHT...ALONG WITH COLDER TEMPERATURES. THERE IS GOOD AGREEMENT BETWEEN THE GFS/ECMWF IN THE OVERALL TIMING/LOCATION OF THE UPPER LEVEL TROUGH. THE GLOBAL GEM IS AN OUTLIER AND WILL USE A GFS/EC SOLUTION. THIS BRINGS THE BEST CHANCES OF LIGHT SNOW ACCUMULATIONS MAINLY ALONG AND WEST OF THE HIGHWAY 83 CORRIDOR. SNOW GROWTH ZONE BECOMES RATHER DEEP BY 00 UTC SUNDAY BUT OMEGA WITHIN THE ZONE IS LIMITED. BUT WITH SNOW RATIOS INCREASING AS THE COLD AIR FILTERS IN...THINK ONE OR TWO INCH ACCUMULATIONS ARE POSSIBLE SATURDAY THROUGH SATURDAY NIGHT OVER THE WESTERN HALF OF NORTH DAKOTA. A NORTHEAST SURFACE FLOW OF 10 TO 20 MPH COULD YIELD SOME REDUCED VISIBILITIES IN FALLING SNOW...BUT SIGNIFICANT BLOWING AND DRIFTING IS NOT EXPECTED AT THIS TIME. THE REMAINDER OF THE FORECAST PERIOD BRINGS BELOW AVERAGE TEMPERATURES AND ONLY MINIMAL PRECIPITATION CHANCES AHEAD OF EACH REINFORCING SHOT OF COLD AIR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 630 AM CST WED JAN 28 2015 WIDESPREAD VLIFR CIGS WILL IMPACT ALL TERMINALS BY EARLY TODAY AS LOW STRATUS AND FOG EXPAND SOUTH AND WEST ACROSS NORTH DAKOTA. LOW STRATUS WILL THEN HOLD ON THROUGH WEDNESDAY NIGHT BUT WILL LIFT TO LIFR/IFR MOST AREAS. && .BIS WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR NDZ002>005-010>013- 021>023-025-036-037. && $$ UPDATE...MM SHORT TERM...NH LONG TERM...TWH AVIATION...TWH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1151 AM CST WED JAN 28 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 316 AM CST WED JAN 28 2015 TRICKY TEMPERATURE FORECAST TODAY...WHICH WILL BE LARGELY DEPENDENT ON THE EXTENT OF CLOUD COVERAGE. VERY MILD 925 MB TEMPERATURES ABOVE ZERO AND SOUTHERLY WINDS AT THE SURFACE WILL TAP INTO SOME CONTINUED SEASONABLY WARM TEMPERATURES. THE QUESTION IS HOW MUCH CLOUD COVER WILL IMPACT WARMING TODAY. THE MOST RECENT HRRR HAS A GOOD HANDLE ON CLOUDS EARLY THIS MORNING...WHICH WILL SHIFT EASTWARD INTO THE MIDDAY HOURS. THINK THE THE NORTHEASTERN HALF OF THE FORECAST AREA...FROM EAST CENTRAL SD INTO SOUTHWEST MN AND THE IOWA GREAT LAKES ARE WILL HOLD ONTO MOSTLY CLOUDY SKIES THE BULK OF THE DAY. KEPT TEMPERATURES ON THE CONSERVATIVE SIDE OF GUIDANCE IN THIS AREA. IF CLOUDS LOOK LESS ABUNDANT...COULD SEE READINGS WARM ABOVE FORECAST HIGHS. ELSEWHERE...MOSTLY SUNNY TO PARTLY CLOUDY SKIES THROUGH MID AFTERNOON WILL GIVE WAY TO CLOUDS WITH THE ANTICIPATED FRONTAL PASSAGE LATE AFTERNOON. SOUTH CENTRAL SD INTO THE MISSOURI VALLEY WILL HAVE THE BEST POTENTIAL TO WARM INTO THE LOW TO MID 50S. WITH THE FRONT TRACKING THROUGH THE AREA MID AFTERNOON INTO THIS EVENING...CLOUDS WILL ROLL BACK INTO THE REGION. NORTHWEST WINDS EXPECTED TO BECOME QUITE WINDY BEHIND THE FRONT WITH 40 TO 50 KT WINDS JUST OFF THE SURFACE. AT THE SURFACE...WINDS WILL LIKELY BE NEAR ADVISORY LEVEL...ESPECIALLY WITH GUSTS AROUND 40 OR 45 MPH. GIVEN THAT THE STRONGEST WINDS ARE EXPECTED IN THE EARLY MORNING HOURS AND ARE MARGINAL FOR AN ADVISORY...WILL HOLD OFF ISSUING ANY HEADLINES FOR NOW. WITH LOW LEVEL STRATUS BLANKETING THE AREA OVERNIGHT...A FAST MOVING SHORTWAVE DROPS ACROSS SOUTHWEST MINNESOTA LATE EVENING INTO THE EARLY MORNING HOURS. NOT MUCH MOISTURE IN PLACE...AND WHILE THE LOW STRATUS DOES THICKEN...THE CLOUD MASS REMAINS LARGELY OUTSIDE THE SNOW GROWTH ZONE. COULD SEE A FEW SNOW ISOLATED SHOWERS DEVELOP MAINLY IN OUR MN COUNTIES...WITH SOME PATCH DRIZZLE ALSO POSSIBLE. SURFACE TEMPERATURES WILL BE NEAR OR JUST ABOVE FREEZING IN THIS AREA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 316 AM CST WED JAN 28 2015 THE SHORTWAVE EXITS THE AREA ON THURSDAY WITH SURFACE HIGH PRESSURE BUILDING INTO THE REGION. IT WILL BE BREEZY WITH A TIGHT GRADIENT ACROSS THE AREA AND GOOD MIXING IN A COLD AIR ADVECTION REGIME. IN RESPONSE TO THE COLDER AIR FILTERING INTO THE REGION BEHIND THE EXITING SHORTWAVE...HIGH TEMPERATURES WILL BE A GOOD 10 TO 15 DEGREES COOLER THAN TODAY...TOPPING OUT IN THE UPPER 20S FROM EAST CENTRAL SD THROUGH SOUTHWESTERN MN...TO UPPER 30S THROUGH THE MO RIVER CORRIDOR. WINDS WILL DIE OFF ON THURSDAY NIGHT...LEADING TO A COLD NIGHT WITH LOWS IN THE LOWER/MID TEENS THROUGH THE EASTERN TWO THIRDS OF THE CWA. TO THE WEST...IT WILL NOT BE QUITE AS COLD WITH AN ENSUING SOUTHEASTERLY FLOW BEHIND THE EXITING HIGH PRESSURE...WITH LOWS GENERALLY LOWER 20S. FRIDAY WILL SEE WARMING WITH A STRENGTHENING SOUTHERLY FLOW ON THE BACKSIDE OF THE HIGH. HIGH TEMPERATURES WILL RUN LOWER 30S NORTHEAST TO AS WARM AS THE MID 40S THROUGH SOUTH CENTRAL SD. ON SATURDAY NORTHERN STREAM UPPER LEVEL ENERGY DROPS OUT OF WESTERN CANADA AND SLIDES SOUTHWARD AS SOUTHERN STREAM ENERGY LIFTS TO THE NORTH...CONVERGING OVER THE CENTRAL PLAINS. STILL SOME MODEL DIFFERENCES ON HOW THIS SCENARIO EVOLVES...BUT DOES POTENTIALLY BRING PRECIPITATION TO AT LEAST OUR SOUTHERN AND EASTERN CWA FOR LATER ON SATURDAY AFTERNOON AND SATURDAY NIGHT. PRECIPITATION TYPE LOOKS TO BE MAINLY IN THE FORM OF SNOW...WITH COOLING THERMAL PROFILES AS LOW PRESSURE OVER THE JAMES BAY BEGINS TO DRIVE COLDER AIR SOUTHWARD. AT THIS POINT SNOWFALL AMOUNTS LOOK TO BE IN THE RANGE OF 2 TO 3 INCHES IN OUR SOUTHEAST...THOUGH WILL HAVE TO WATCH THE TRACK OF THIS SYSTEM FOR GREATER SNOWFALL AMOUNTS IF IT TRENDS FARTHER TO THE NORTH. IT STILL WONT BE UNREASONABLY COLD ON SATURDAY WITH HIGHS MAINLY IN THE 30S...BUT BY SATURDAY NIGHT AND SUNDAY MUCH COLDER AIR WILL HAVE SETTLED INTO THE REGION WITH HIGHS ON SUNDAY MOSTLY IN THE TEENS. THE COLD AIR THEN LOOKS TO LINGER THROUGH NEXT MONDAY...WITH SOME MODERATION POSSIBLE BY TUESDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1139 AM CST WED JAN 28 2015 COLD FRONT MOVING THROUGH THE AREA THIS AFTERNOON WITH GUSTY NORTHWEST WINDS BEHIND THE FRONT. WILL ALSO HAVE MVFR STRATUS...WITH THE CHANCE FOR SOME LIGHT DRIZZLE/FREEZING DRIZZLE ACROSS SOUTHWEST MINNESOTA AFTER 03Z -15ZISH THURSDAY MORNING. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM... LONG TERM...JM AVIATION...
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
328 PM CST WED JAN 28 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 328 PM CST WED JAN 28 2015 AT 3 PM...SURFACE LOWS WERE LOCATED OVER NORTHEAST NEBRASKA AND WEST OF HUDSON BAY. IN BETWEEN THESE 2 LOW PRESSURE SYSTEMS... A TROUGH EXTENDED SOUTH ACROSS THE EASTERN DAKOTAS. LIKE THE 28.00Z AND 28.06Z MODELS...THE 28.12Z MODELS SHOW THAT THIS TROUGH WILL MOVE EAST TONIGHT. AS IT APPROACHES...MODERATE TO STRONG 925 MB MOISTURE TRANSPORT DEVELOPS AHEAD OF IT ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA THIS EVENING AND WESTERN WISCONSIN TONIGHT. THIS WILL AID IN MOISTENING THE AIR MASS BELOW 800 MB. SOUNDINGS GENERALLY SHOW THAT THERE IS NO INTRODUCTION OF ICE FROM ALOFT...THUS KEEPING THE PRECIPITATION IN FORM OF SUPER COOLED WATER DROPLETS. THERE WERE A FEW -8C SHOWING AT TIMES...SO TOTALLY CANNOT RULE OUT MAYBE A BIT OF SNOW...BUT NOT ENOUGH TO ACCUMULATE. WITH THE PRECIPITATION BEING DRIZZLE...THE MAIN QUESTION WILL BE HOW COLD WILL BE THE SURFACE TEMPERATURES. FILTERED SUNSHINE SOUTH OF INTERSTATE 90 HAS ALLOWED SURFACE TEMPERATURES TO WARM INTO THE LOWER AND MID 30S...AND PAVEMENT TEMPERATURES TO AROUND 40 DEGREES. WITH THE LOSS OF SUNSHINE...THE PAVEMENT TEMPERATURES WILL QUICKLY FALL. HOWEVER THE SOUTHERLY WINDS WILL LIKELY KEEP THE TEMPERATURES AT OR ABOVE FREEZING WEST AND SOUTH OF INTERSTATE 94. AS A RESULT...THE FREEZING DRIZZLE THREAT THERE LOOKS TO BE SCATTERED. MEANWHILE NORTH AND EAST OF INTERSTATE 94 SURFACE TEMPERATURES HAVE BEEN SLOW TO WARM. THIS IS DUE TO THE SOUTHEAST WINDS BLOWING OVER THE SNOW PACK. WITH TEMPERATURES ALREADY BELOW FREEZING DECIDED TO ISSUE A FREEZING RAIN ADVISORY FROM 9 AM TO 6 AM FOR THESE AREAS. ONLY A LIGHT GLAZE IS EXPECTED TO DEVELOP ON UNTREATED ROADS AND SURFACES. ON THURSDAY MORNING...THE MODELS SHOW THAT A SECOND SHORT WAVE WILL MOVE QUICKLY EAST ACROSS THE AREA. WITH SOME MODERATE COLD AIR ADVECTION IN THE WAKE OF THIS TROUGH...THE TEMPERATURES WILL COOL ENOUGH FOR THERE TO BE A MIX OF LIGHT SNOW AND FREEZING DRIZZLE/DRIZZLE. LITTLE...IF ANY...ACCUMULATION IS EXPECTED. ALSO WITH THE SOUNDINGS SHOWING MOISTURE TRAPPED BELOW THE SUBSIDENCE INVERSION...THE CLOUDS WILL LINGER THROUGH THE MORNING AND SLOWLY ERODE DURING THE EVENING AS DRIER AIR ADVECTS INTO THE REGION. FOR THE ENTIRE DAY THURSDAY...THE MODELS SHOW VERY STEEP LOW LEVEL LAPSE RATES BETWEEN 950 AND 900 MB. THIS WILL ALLOW THE NORTHWEST WINDS TO GUST INTO THE 25 TO 30 MPH RANGE ACROSS WESTERN WISCONSIN...AND INTO THE 30 TO 35 MPH RANGE IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 328 PM CST WED JAN 28 2015 ON FRIDAY NIGHT...A CANADIAN COLD FRONT WILL MOVE QUICKLY SOUTHEAST ACROSS THE AREA. THE NAM SHOWS THAT THERE WILL BE ENOUGH SATURATION FOR SOME LIGHT SNOW. MEANWHILE THE OTHER MODELS SHOW THAT THE BEST LIFT AND SATURATION WILL REMAIN ACROSS NORTHERN MINNESOTA...NORTHERN WISCONSIN...AND UPPER MICHIGAN. WITH THE MODEL CONSENSUS...KEPT THE FORECAST DRY FOR NOW. FROM SATURDAY AFTERNOON INTO SUNDAY...THE MODELS ARE NOW SHOWING THAT THE SHORT WAVE FROM FRIDAY NIGHT WILL PUSH THE FRONT FAR ENOUGH SOUTH THAT MUCH OF THE SNOW ASSOCIATED WITH THIS SYSTEM WILL REMAIN SOUTH AND WEST OF THE FORECAST AREA. THE ONLY MODEL STILL SHOWING ADVISORY SNOW IS THE GEM. BOTH THE GFS AND ECMWF HAVE SIGNIFICANTLY SHIFTED MUCH OF THE SNOW SOUTH INTO THE MID MISSISSIPPI RIVER VALLEY. SINCE THIS IS A RELATIVELY NEW DEVELOPMENT...STILL KEPT THE SNOW CHANCES IN THE MODEL CONSENSUS FOR SATURDAY NIGHT AND SUNDAY...BUT REMOVED THEM FOR SATURDAY AFTERNOON. IF THIS TREND CONTINUES...FUTURE SHIFTS CAN TAKE THEM OUT OR LOWER THESE SNOW CHANCES FURTHER. TEMPERATURES FOR EARLY NEXT WEEK...LOOK TO BE MUCH COLDER WITH HIGH TEMPERATURES IN THE SINGLE DIGITS AND TEENS...AND LOW TEMPERATURES ON EITHER SIDE OF ZERO. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1142 AM CST WED JAN 28 2015 MAIN AVIATION CONCERNS IS THE POSSIBILITY OF FREEZING DRIZZLE THIS EVENING INTO TONIGHT AT BOTH RST AND LSE TAF SITES...AND LIFR/IFR/MVFR CONDITIONS AT THE TAF SITES THROUGH THE TAF PERIOD. SURFACE LOW TRACKS INTO SOUTHERN IOWA AND NORTHERN ILLINOIS TONIGHT. THE LATEST 28.12Z NAM/GFS AND 28.15Z RAP ARE INDICATING SURFACE TEMPERATURES WILL BE TRICKY THIS EVENING INTO TONIGHT...AS WARM AIR ADVECTS INTO BOTH TAF SITES THIS AFTERNOON. THE MODELS SUGGEST TEMPERATURES WILL HOVER AROUND THE FREEZING MARK AND ABOVE FREEZING THIS EVENING INTO TONIGHT. WITH ENOUGH LIFT AND THE NEAR SURFACE BOUNDARY LAYER MOIST...PRECIPITATION TYPE WILL BE ALL LIQUID AND DEPENDING ON TEMPERATURES...THERE IS POTENTIAL FOR PATCHY FREEZING DRIZZLE TO OCCUR AT BOTH RST AND LSE TAF SITES FROM 02Z THURSDAY INTO 12Z THURSDAY. AT THIS TIME...WITH THE FREEZING DRIZZLE EXPECTED TO BE PATCHY...DID NOT INTRODUCE INTO THE TAFS. NEXT CONCERN ARE LIFR/IFR/MVFR CONDITIONS AT BOTH TAF SITES THROUGH THE TAF PERIOD. LOW LEVEL MOISTURE WILL CONTINUE TO LINGER OVER MUCH OF THE REGION THIS AFTERNOON INTO THURSDAY. CEILINGS WILL HOVER IN THE LIFR AND IFR CONDITIONS AT RST...AS CEILINGS CURRENTLY BELOW 500 FEET AND RISE INTO THE 500-1000 FEET RANGE LATE THIS AFTERNOON. THEN...AS SURFACE LOW IN SOUTHERN IOWA AND SUNSET CEILINGS WILL LOWER BELOW 500 FEET THIS EVENING. AT THE LSE TAF SITE CEILINGS WILL LOWER INTO THE 500-1000 FEET RANGE AROUND 02Z AND RISE BACK INTO THE MVFR RANGE AROUND 09Z THURSDAY. WITH SURFACE LOW/FRONT PASSAGE BETWEEN 09-12Z THURSDAY...PRESSURE GRADIENT TIGHTENS ON THE BACKSIDE AND NORTHWEST WINDS INCREASE. HAVE INTRODUCE WIND GUST OF 27 KNOTS AT RST TAF SITE AND 23 KNOTS AT LSE TAF SITE AT 12Z THURSDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FREEZING RAIN ADVISORY FROM 9 PM THIS EVENING TO 6 AM CST THURSDAY FOR WIZ017-029-034-042>044. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1142 AM CST WED JAN 28 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 332 AM CST WED JAN 28 2015 MAIN CONCERNS THIS PERIOD...DZ/FZDZ CHANCES TONIGHT...CLOUDS AND TEMPERATURES BOTH TODAY AND TONIGHT. 06Z DATA ANALYSIS HAD HIGH PRESSURE OVER THE OH VALLEY AND DEEPENING LOW PRESSURE OVER THE CENTRAL/NORTHERN PLAINS. SFC OBS AND FOG- PRODUCT IMAGERY SHOW AN IFR/MVFR STRATUS DECK ACROSS MUCH OF WI/MN AND EASTERN IA. LATEST AVAILABLE PILOT REPORTS INDICATED THIS CLOUD DECK ABOUT 1000 FT THICK. THIS MOISTURE/CLOUDS TRAPPED UNDER A STRONG AND STRENGTHENING INVERSION NEAR 900MB. THE CLOUD BLANKET AND INCREASING SOUTHEAST GRADIENT WINDS HOLDING TEMPS STEADY IN THE MID/UPPER 20S ACROSS MUCH OF THE REGION EARLY THIS MORNING. INITIALIZATIONS OF 28.00Z MODELS GENERALLY LOOK QUITE GOOD. SHORTWAVE RIDGING QUICKLY MOVES ACROSS THE UPPER MIDWEST TODAY AND NORTHERN/SOUTHERN STREAM ENERGY CARVES OUT TROUGHING IN THE CENTRAL/ NORTHERN PLAINS. THE 2 PIECES OF ENERGY NEARLY PHASE TONIGHT AS THEY AND DEEPENING MID LEVEL TROUGHING MOVES ACROSS THE MID/UPPER MS VALLEY. THE TIGHTER CONSENSUS FOR TODAY/TONIGHT FAVORS A COMPROMISE OF THE EARLIER 26.00Z/27.00Z RUNS. SHORT TERM FCST CONFIDENCE REMAINS GOOD BUT THE FCST HINGES ON LOWER LEVEL MOISTURE WHICH THE MODELS TYPICALLY STRUGGLE WITH. IN THE SHORT TERM...THE STRATUS DECK WILL ONCE AGAIN BE PROBLEMATIC TODAY FOR HIGH TEMPS. SOUTHEAST TO SOUTHWEST SFC-850MB GRADIENT FLOW INCREASE ACROSS THE AREA TODAY AS THE PLAINS LOW MOVE TO NEAR KFSD/KOMA THIS AFTERNOON. INVERSION OVER THE AREA REMAINS STRONG UNDER THE INCREASING 925-850MB WARM ADVECTION. BY THIS AFTERNOON... DEEPER/STRONGER LIFT ARRIVES...WITH AN INCREASE OF LOWER LEVEL MOISTURE. ALL THIS POINTS TO THE LOWER STRATUS HANGING TOUGH OVER THE AREA TODAY WITH LITTLE IF ANY SUNSHINE. CIRRUS SHIELD AHEAD OF THE MID/UPPER LEVEL TROUGH MOVES OVER THE REGION FOR THE AFTERNOON AS WELL. SOUTH-SOUTHEAST WINDS OVER AND LOW LEVEL WARM ADVECTION OVER THE AREA TODAY...SO EXPECT TEMPS TO WARM A LITTLE...BUT ONLY TO THE MID/UPPER 30S ACROSS MOST OF THE FCST AREA. SFC THRU MID LEVEL TROUGH AXIS MOVES ACROSS THE AREA TONIGHT...WITH MOISTURE/SATURATION IN ROUGHLY THE SFC-800MB PORTION OF THE COLUMN. LOWER LEVEL LIFT/CONVERGENCE WITH THE SFC-850MB TROUGH AXIS...WITH DEEP LAYERED LIFT/DIVERGENCE ALOFT AHEAD OF THE SHORTWAVES AND MID LEVEL TROUGH AXIS. MODEL SOUNDINGS CONTINUE TO SHOW COLDEST TEMPS IN THE LOWER SATURATED PORTION OF THE COLUMN AROUND -5C...INDICATING NO ICE IN THE CLOUD DEPTH. PRECIP CHANCES TONIGHT REMAIN MAINLY -DZ/ -FZDZ. CONFINED THE HIGHEST CHANCES BETWEEN 03Z-09Z WHEN THE SFC- 850MB TROUGH AXIS AND ITS CONVERGENCE SLIDES ACROSS THE FCST AREA. MORE CONSISTENT SIGNAL AMONG THE MODELS FOR LIGHT PRECIP PRODUCTION REMAINS OVER THE NORTHEAST HALF OF THE FCST AREA...WITH HIGHER PRECIP CHANCES THERE TONIGHT. GREATER THREAT OF MINOR ICING IS OVER THE NORTHEAST HALF OF THE FCST AREA WERE TEMPS TODAY/TONIGHT WILL BE MORE IN THE LOWER 30S AND ROAD TEMPS WILL REMAIN CLOSER TO OR BELOW FREEZING. MAY YET NEED A FREEZING RAIN/DRIZZLE ADVISORY FOR THE NORTHEAST 1/3 TO 1/2 OF THE FCST AREA. WILL LET DAY CREW HAVE ANOTHER CYCLE OF MODELS TO LOOK AT AND SEE WHAT SFC TEMPS DO TODAY TO MAKE THE CALL ON THAT. WITH THICKER LOW CLOUDS TONIGHT...THE DZ/FZDZ CHANCES AND SOME PATCHY FOG...NEARLY STEADY TEMPS EXPECTED DURING THE EVENING... THEN FALLING LATE AFTER THE TROUGH AXIS PASSES/LOW LEVEL COLD ADVECTION/INCREASING NORTHWEST WINDS SPREAD ACROSS THE AREA. BY THIS TIME BULK OF THE DEEP LAYERED LIFT HAS SHIFTED EAST OF THE AREA WITH THE TROUGH AXIS AND DZ/FZDZ CHANCES WILL BE DECREASING. TRENDED TOWARD COOLER OF GUIDANCE HIGHS TODAY AND WARMER OF GUIDANCE LOWS TONIGHT. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 332 AM CST WED JAN 28 2015 MAIN FCST CONCERNS FOR THU THRU FRI NIGHT...LINGERING DZ/FZDZ CHANCES THU MORNING...CLOUD/TEMPERATURE TRENDS THRU THE PERIOD. 28.00Z MODELS IN GOOD AGREEMENT FOR A SECOND NORTHERN STREAM SHORTWAVE TO DROP QUICKLY ACROSS THE WESTERN GREAT LAKES THU AFTERNOON/EVENING. GOOD BETWEEN MODEL AND RUN-TO-RUN CONSISTENCY FOR HGTS TO THEN RISE FRI/FRI NIGHT...AHEAD OF THE NEXT NORTHERN/ SOUTHERN STREAM ENERGY HEADED TOWARD THE CENTRAL CONUS. FCST CONFIDENCE IN THE THU THRU FRI NIGHT PERIOD IS GOOD THIS CYCLE. THIS PERIOD SHAPING UP TO BE A COOLER/DRY/QUIET PERIOD BEFORE THE NEXT STRONGER SYSTEM TAKES AIM AT THE UPPER MIDWEST FOR THE WEEKEND. LOW LEVEL COLD ADVECTION AND DEEPER LAYERED SUBSIDENCE CONTINUE TO SPREAD ACROSS THE AREA THU MORNING. MAINLY LIMITED ANY LINGERING DZ/ FZDZ CHANCES TO THE 12-15Z PERIOD OVER THE EAST HALF OF THE FCST AREA. SHORTWAVE DROPPING ACROSS THE WESTERN GREAT LAKES THU AFTERNOON/EVENING MAINLY PROVIDES THE AREA WITH A REINFORCING SHOT OF LOW LEVEL COLD ADVECTION. APPEARS HIGHS THU WILL BE IN THE MORNING WITH STEADY/SLOWING FALLING TEMPS THRU THE DAY UNDER THE STRONGER COLD ADVECTION. STRONGER SUBSIDENCE/COLD ADVECTION AND CAN HIGH PRESSURE BUILDING IN SHOULD CLEAR OUT THE LOWER CLOUDS THU AFTERNOON/NIGHT. SFC RIDGE AXIS DRIFTS ACROSS THE AREA LATE THU NIGHT/FRI MORNING...UNDER WHAT SHOULD BE MOSTLY CLEAR SKIES. THU NIGHT LOWS LOOKING TO BE CLOSER TO NORMAL THAN THEY/VE BEEN DURING THE PAST 2 WEEKS. LOW LEVEL WARM ADVECTION RETURNS FRI AS THE SFC- 850MB RIDGE AXIS MOVES SOUTH OF THE AREA. STRONGER OF THIS SPREADS ACROSS THE AREA FRI NIGHT...WITH LOWS LOOKING TO BE FRI EVENING THEN SLOWLY RISING TEMPS AFTER MIDNIGHT AS CLOUDS START TO INCREASE AND SOUTHWEST GRADIENT WINDS FOR BOUNDARY LAYER MIXING INCREASE A BIT. USED THE MODEL/ENSEMBLE BLEND OF GUIDANCE HIGHS/LOWS FOR THU THRU FRI NIGHT. FOR SATURDAY THRU TUESDAY.../DAYS 4 TO 7/... MAIN FCST CONCERNS THIS PERIOD...SNOW CHANCES LATE SAT/SAT NIGHT/SUN...COLD TEMPERATURES MOM-TUE. 28.00Z MEDIUM RANGE MODELS SHOW IMPROVING AGREEMENT SAT/SUN FOR NORTHERN/SOUTHERN STREAM ENERGY TO AT LEAST PARTIALLY PHASES OVER THE CENTRAL CONUS. TREND IS A BIT STRONGER/MORE PHASED WITH THE STREAMS/SHORTWAVES OVER THE CENTRAL CONUS BY SUNDAY. GOOD BETWEEN MODEL AND RUN-TO-RUN CONSISTENCY FOR THE TROUGH AXIS TO THEN MOVE ACROSS THE MID/UPPER MS VALLEY SUN NIGHT...LEAVING THE DOOR OPEN FOR NORTHWEST FLOW AND A STRONGER SHOT OF CANADIAN/ARCTIC AIR TO DROP INTO THE UPPER MIDWEST FOR EARLY NEXT WEEK. GIVEN SOME LOWER LEVEL DETAIL DIFFERENCES...FCST CONFIDENCE FOR SAT THRU TUE REMAINS AVERAGE THIS CYCLE. PHASING SHORTWAVES/DEEPENING TROUGH OVER THE PLAINS SAT/SUN SENDS INCREASING MOISTURE NORTHWARD TOWARD THE UPPER MIDWEST FOR THE WEEKEND. PW VALUES OF AROUND 1/2 INCH INDICATED IN THE INFLOW AIRMASS AHEAD OF THE DEVELOPING TROUGH/SFC LOW. THIS MOISTURE BEING PUSHED INTO A COLUMN WITH SFC-600MB TEMPS FAVORING A DEEP DENDRITIC GROWTH ZONE AND FAVORABLE LIFT/DIVERGENCE IN THE MID/UPPER LEVELS AHEAD OF THE PLAINS TROUGH. MODEL SOUNDINGS/X-SECTIONS SHOWING COLUMN SATURATED FROM THE SFC TO 300MB OVER MUCH OF THE FCST AREA FOR BY LATER SAT NIGHT AND FOR SUN. DETAIL DIFFERENCES INCLUDE HOW MUCH AND QUICKLY PHASING ACTUALLY OCCURS AND HOW FAR NORTHWARD THE GREATER THE 925-700MB MOISTURE AND THERMODYNAMIC FORCING ENDS UP OCCURRING. POTENTIAL ALSO EXISTS FOR A LONGER DURATION PERIOD OF SNOW FOR PARTS OR ALL OF THE FCST AREA FROM SAT NIGHT INTO SUN NIGHT. SNOW CHANCES IN THE 30-50 PERCENT RANGE FOR SAT NIGHT/SUNDAY LOOK GOOD FOR NOW...UNTIL THE DETAILS GET SORTED OUT. OVER WHAT WOULD BE FRESH SNOW COVER FOR MUCH/ALL OF THE AREA...NORTHWEST FLOW BEHIND THE TROUGH SENDS ANOTHER CAN/ARCTIC HIGH INTO THE UPPER MIDWEST FOR SUN NIGHT INTO TUE. 925MB TEMPS PROGGED IN THE -15C TO -20C RANGE MON INTO MON NIGHT. TEMPS TO START NEXT WEEK CONTINUE TO TREND BELOW TO MUCH BELOW NORMAL. MODEL/ENSEMBLE CONSENSUS OF HIGHS/LOWS FOR SAT THRU TUE LOOKS GOOD AT THIS TIME. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1142 AM CST WED JAN 28 2015 MAIN AVIATION CONCERNS IS THE POSSIBILITY OF FREEZING DRIZZLE THIS EVENING INTO TONIGHT AT BOTH RST AND LSE TAF SITES...AND LIFR/IFR/MVFR CONDITIONS AT THE TAF SITES THROUGH THE TAF PERIOD. SURFACE LOW TRACKS INTO SOUTHERN IOWA AND NORTHERN ILLINOIS TONIGHT. THE LATEST 28.12Z NAM/GFS AND 28.15Z RAP ARE INDICATING SURFACE TEMPERATURES WILL BE TRICKY THIS EVENING INTO TONIGHT...AS WARM AIR ADVECTS INTO BOTH TAF SITES THIS AFTERNOON. THE MODELS SUGGEST TEMPERATURES WILL HOVER AROUND THE FREEZING MARK AND ABOVE FREEZING THIS EVENING INTO TONIGHT. WITH ENOUGH LIFT AND THE NEAR SURFACE BOUNDARY LAYER MOIST...PRECIPITATION TYPE WILL BE ALL LIQUID AND DEPENDING ON TEMPERATURES...THERE IS POTENTIAL FOR PATCHY FREEZING DRIZZLE TO OCCUR AT BOTH RST AND LSE TAF SITES FROM 02Z THURSDAY INTO 12Z THURSDAY. AT THIS TIME...WITH THE FREEZING DRIZZLE EXPECTED TO BE PATCHY...DID NOT INTRODUCE INTO THE TAFS. NEXT CONCERN ARE LIFR/IFR/MVFR CONDITIONS AT BOTH TAF SITES THROUGH THE TAF PERIOD. LOW LEVEL MOISTURE WILL CONTINUE TO LINGER OVER MUCH OF THE REGION THIS AFTERNOON INTO THURSDAY. CEILINGS WILL HOVER IN THE LIFR AND IFR CONDITIONS AT RST...AS CEILINGS CURRENTLY BELOW 500 FEET AND RISE INTO THE 500-1000 FEET RANGE LATE THIS AFTERNOON. THEN...AS SURFACE LOW IN SOUTHERN IOWA AND SUNSET CEILINGS WILL LOWER BELOW 500 FEET THIS EVENING. AT THE LSE TAF SITE CEILINGS WILL LOWER INTO THE 500-1000 FEET RANGE AROUND 02Z AND RISE BACK INTO THE MVFR RANGE AROUND 09Z THURSDAY. WITH SURFACE LOW/FRONT PASSAGE BETWEEN 09-12Z THURSDAY...PRESSURE GRADIENT TIGHTENS ON THE BACKSIDE AND NORTHWEST WINDS INCREASE. HAVE INTRODUCE WIND GUST OF 27 KNOTS AT RST TAF SITE AND 23 KNOTS AT LSE TAF SITE AT 12Z THURSDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RRS LONG TERM....RRS AVIATION...DTJ