Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/10/14


AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
342 AM PST WED JAN 8 2014 .DISCUSSION...AS OF 3:00 AM PST WEDNESDAY...PLENTY OF CLOUDS ACROSS THE CWA THIS MORNING ALONG WITH A MORE PRONOUNCED WESTERLY FLOW AT THE SURFACE WHICH HELPED TO PRODUCE A FEW AREAS OF DRIZZLE. IN FACT, SFO ENDED UP REPORTING A TRACE OF RAINFALL CLOSE TO MIDNIGHT MARKING THE FIRST TIME IN ABOUT 30 DAYS THAT ANY RAIN HAS BEEN REPORTED THERE. WEBCAMS AND SURFACE OBS ALSO SHOWS SOME POCKETS OF FOG ALONG WITH A REPORT DOWN TO A QUARTER OF A MILE AROUND SANTA ROSA. IN MANY RESPECTS MANY OF THE OBS SEEM LIKE WHAT WE WOULD USUALLY SEE DURING EARLY SUMMER "JUNE GLOOM" MORNINGS AND NOT WHAT YOU WOULD EXPECT FOR JANUARY. THE ONSHORE FLOW WILL HELP TO KEEP HIGHS ON THE COOLER SIDE -- LOOK FOR 50S TO LOWER 60S AT THE COAST WITH 60S INLAND. A SYSTEM FROM THE PACNW WILL DIVE TO THE SOUTHEAST ON THURSDAY. PREVIOUS MODEL RUNS HAD BROUGHT THE FAR SOUTHERN AND WESTERN EXTENT OF MOISTURE INTO THE NORTH BAY FOR THURSDAY. THAT LOOK INCREASINGLY UNLIKELY AS THE LOW WILL SIMPLY BE TOO FAR TO THE EAST. RAIN CHANCES WERE REMOVED FROM THE GRIDS. TEMPERATURES ON THURSDAY WILL BE SIMILAR TO TODAY. WARMER WEATHER WILL RETURN FOR FRIDAY AS 850 MB TEMPS INCREASE AND A RIDGE OF HIGH PRESSURE BUILDS BACK TO OUR CWA. SOME INLAND SPOTS WILL RETURN BACK TO THE LOWER 70S. COASTAL AREAS WILL LIKELY NOT WARM AS MUCH DUE TO THE ONSHORE FLOW CONTINUING. OVER THE WEEKEND THE STRONGEST PACIFIC SYSTEM OF THE WEEK MOVES TO THE PACNW/BC COASTLINE. PROGS FOR SATURDAY HAVE BEEN IN FAIRLY CONSISTENT BRINGING THE ASSOCIATED COLD FRONT INTO NORTHERN CALIFORNIA DURING THE DAY. THE BULK OF THE MOISTURE WILL STAY NORTH OF OUR CWA, BUT LOOKS INCREASINGLY LIKELY THAT THE FAR SOUTHERN EXTENT WILL MAKE IT INTO THE NORTH BAY AND POSSIBLY AS FAR SOUTH AS SANTA CRUZ COUNTY. POPS WERE INCREASE INTO THE HIGH CHANCE CATEGORY FOR NAPA/SONOMA AND GENERALLY SLIGHT CHANCE FOR SF BAY DOWN TO SANTA CRUZ. RAINFALL TOTALS WILL BE LOW AND RAIN DURATION IS EXPECTED TO JUST BE FOR A FEW HOURS AS THE FRONT QUICKLY ADVANCES. AROUND A TENTH CAN BE EXPECTED OVER THE NORTH BAY AND A FEW HUNDREDTHS AROUND SF INTO SAN MATEO COUNTY. AND AS QUICKLY AS THE RAIN CHANCES ARRIVE, THEY WILL END AS THE STRONG RIDGE OFF THE COAST REBUILDS. INTERESTING TO NOTE THAT THE MODELS ARE DEPICTING AN EXTREMELY AMPLIFIED LONGWAVE RIDGE EXTENDING NEARLY TO THE ARCTIC CIRCLE BY THE END OF NEXT WEEK AS THE COLD LOW REPOSITIONS ITSELF BACK NEAR HUDSON BAY WITH THE RIDGE HERE EXTENDING FROM THE WEST COAST OF THE CONUS NORTH THROUGH BC, YUKON TERRITORY AND ALASKA. AT THE SAME TIME THE SURFACE FLOW WILL RETURN TO BEING OFFSHORE AND 850MB TEMPS WILL INCREASE UP TO 3 STANDARD DEVIATIONS ABOVE NORMAL. RECORD HIGHS WILL LIKELY BE HIT NEXT WEEK -- POSSIBLY AT MANY SPOTS. MJO FORECAST SHOWS VIRTUALLY NO MOVEMENT OVER THE NEXT TWO WEEKS MAKING IT THAT MUCH HARDER FOR THE RIDGE TO BE UNDERCUT GOING INTO AT LEAST THE 20TH OF JANUARY. && .CLIMATE...IN A TYPICAL JANUARY, SAN FRANCISCO WOULD HAVE HIGHS 60 OR ABOVE 7 TIMES. WE HAVE ALREADY EQUALED THAT NUMBER FOR THE MONTH. MONTHLY RAINFALL TOTALS ARE SIMILAR FOR DECEMBER, JANUARY, AND FEBRUARY FOR MOST OF OUR AREA. BY MARCH, THE EXPECTED AMOUNT DECREASES BY ABOUT 25 PERCENT. IN APRIL WE USUALLY RECEIVE ONLY 5 TO 10 PERCENT OF OUR RAIN FOR THE YEAR. WE HAVE NOW GONE THROUGH WHAT WOULD USUALLY BE OVER 40% OF OUR RAINFALL FOR THE WATER YEAR. FOR THE WATER YEAR, BEN LOMOND HAS ONLY PICKED UP 2.39" WHICH IS JUST 11 PERCENT OF NORMAL TO DATE. IN ORDER TO GET TO 100% BY THE END OF JUNE, 48.09" WILL NEED TO FALL (OR MORE THAN 0.43" WOULD NEED TO FALL EVERY DAY UNTIL THE END OF APRIL.) && .AVIATION...AS OF 3:42 AM PST WEDNESDAY...A STORM SYSTEM APPROACHING THE NORTHERN CA COASTLINE WILL CONTINUE TO BRING LIGHT TO MODERATE ONSHORE FLOW AND ALLOW COASTAL LOW CLOUDS TO IMPACT THE TERMINALS. LOW MVFR TO OCCASIONAL IFR CIGS WILL BE PRESENT...MAINLY THROUGH THE SF BAY AREA...THROUGH 21Z. LOW CONFIDENCE. THE HRRR AND WRF ARE THE ONLY SHORT TERM MODELS HANDLING THE LOW CLOUDS CORRECTLY...WITH VERY PATCHY CIGS OVER THE MONTEREY BAY AND NORTH BAY. AFTER A BRIEF BREAK IN THE CLOUDINESS...LOW CLOUDS ARE FORECAST TO RETURN AS EARLY AS 02Z THURSDAY. AGAIN VERY LOW CONFIDENCE FORECAST...ESPECIALLY WITH REGARDS TO TIMING. VICINITY OF KSFO...MVFR TO OCCASIONAL IFR CIGS POSSIBLE THROUGH 21Z...LOW CONFIDENCE. PATCHY DRIZZLE WILL BE POSSIBLE THROUGH THE EARLY MORNING HOURS. OTHERWISE...MODERATE ONSHORE WINDS THIS AFTERNOON AND A RETURN OF MVFR CIGS BETWEEN 03 AND 06Z THURSDAY. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...PATCHY MVFR CIGS WILL BE POSSIBLE THROUGH 16Z. OTHERWISE...LIGHT TO MODERATE ONSHORE WINDS THIS AFTERNOON WITH AN EARLY RETURN OF MVFR CIGS AROUND 02Z. LOW CONFIDENCE. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM && $$ PUBLIC FORECAST: BELL AVIATION: RILEY CLIMATE: BELL VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
829 PM PST TUE JAN 7 2014 .UPDATE... RADAR AND SURFACE REPORTS INDICATE SOME LIGHT RAIN NEAR THE OREGON BORDER JUST TO THE NORTHWEST OF THE SURPRISE VALLEY. THE 00Z GFS/NAM AND 3KM HRRR SUGGEST SOME LIGHT SHOWERS OVERNIGHT FOR THE SURPRISE VALLEY AND FAR NORTHWEST NV OVERNIGHT. SO UPDATED FORECAST TO REFLECT THESE LATEST TRENDS. OTHERWISE VARIABLE CLOUDS AND GENERALLY LIGHT WINDS EXCEPT ON RIDGES WHERE GUSTS TO 50 MPH ARE EXPECTED. THE WINDS WERE GUSTING TO 70 MPH ABOVE 14000 FEET IN THE WHITE MOUNTAINS. HOHMANN && .PREVIOUS DISCUSSION... /ISSUED 224 PM PST TUE JAN 7 2014/ SYNOPSIS... A SERIES OF WEAK DISTURBANCES BRUSH THE REGION THIS WEEK WITH LITTLE TO NO PRECIPITATION EXPECTED THROUGH WEDNESDAY. A QUICK MOVING FRONT MAY PROVIDE RAIN AND SNOW SHOWERS THURSDAY WITH ANOTHER LOW PRESSURE SYSTEM BRINGING ADDITIONAL CHANCES FOR RAIN AND SNOW TO THE REGION ON SATURDAY. SHORT TERM... A SERIES OF WEAK DISTURBANCES WILL PASS THROUGH THE EASTERN SIERRA AND WESTERN NEVADA THIS WEEK WITH VARYING CHANCES FOR PRECIPITATION WITH EACH WAVE. THE NEXT WAVE WILL BRUSH THROUGH THE PACIFIC NORTHWEST ON WEDNESDAY BRINGING AN INCREASE IN WINDS ACROSS NORTHERN LASSEN AND NORTHERN WASHOE COUNTIES. UNFORTUNATELY PRECIPITATION CHANCES WILL REMAIN NORTH AND EAST OF NEVADA WITH THIS SYSTEM. THE NEXT QUICK MOVING SYSTEM WILL DROP THROUGH THE SIERRA AND WESTERN NEVADA ON THURSDAY BRINGING BREEZY WINDS AND INCREASED POTENTIAL FOR PRECIPITATION. WEST TO SOUTHWEST WINDS WILL INCREASE AHEAD OF THE COLD FRONT WITH GUSTS AROUND 30 MPH FOR THE LOWER VALLEYS AND GUSTS BETWEEN 50-60 MPH LIKELY FOR THE RIDGES. THE COLD FRONT WILL ALSO BRING SNOW LEVELS DOWN TO AROUND 5000 FEET NEAR INTERSTATE 80 AND AS LOW AS 3500 FEET NEAR THE OREGON BORDER. THE BEST CHANCES FOR PRECIPITATION WILL REMAIN NORTH OF INTERSTATE 80, BUT FORECASTER CONFIDENCE REMAINS MEDIUM WITH QPF AS THE NAM AND GFS DIFFER DRASTICALLY FROM EACH OTHER. THE NAM FORECAST REMAINS DRY WHILE THE GFS STILL BRINGS PRECIPITATION THROUGH THE REGION WITH THE COLD FRONT ON THURSDAY. THIS RESULTED IN LITTLE CHANGE FOR THE ONGOING QPF FORECAST WITH QPF AMOUNTS LESS THEN 0.10" AREAWIDE. SNOW IS POSSIBLE DOWN TO VALLEY FLOORS BUT LITTLE ACCUMULATION IS EXPECTED AS THE SYSTEM MOVES THROUGH QUICKLY. MODELS ARE IN GOOD AGREEMENT WITH THE EXIT OF THE SHORTWAVE BY THURSDAY AFTERNOON, BUT RESIDUAL MOISTURE AND NORTHEAST UPSLOPE FLOW MAY RESULT IN SOME ISOLATED SHOWERS, ESPECIALLY SOUTH OF INTERSTATE 80 ALONG THE SIERRA. THE RIDGE QUICKLY RETURNS ON FRIDAY WITH INCREASING TEMPERATURES AND DRIER CONDITIONS FORECAST. EKL LONG TERM...SATURDAY THROUGH TUESDAY... OVERALL FORECAST REMAINS LARGELY UNCHANGED WITH MODERATE CONFIDENCE IN A SYSTEM IMPACTING THE SIERRA AND WESTERN NEVADA SATURDAY INTO SUNDAY, HOWEVER CONFIDENCE IS LOWER IN THE EXACT TRACK AND TIMING OF THIS SYSTEM. IN ANY EVENT, WINDS WILL INCREASE SATURDAY, ESPECIALLY NORTH OF INTERSTATE 80, WITH A DECENT SURFACE GRADIENT IN PLACE AND 40-60 KTS AT 700 MB. HAVE INCREASED WINDS IN THE FORECAST TO REFLECT THIS. THERE IS PLENTY OF MOISTURE AND A DECENT JET ASSOCIATED WITH THE SYSTEM AS IT MOVES INTO THE PACIFIC NORTHWEST COAST, BUT STILL VARIATION IN HOW FAR SOUTH THE JET WILL DROP SOUTH. YESTERDAY, THE GFS KEPT THE JET WELL TO THE NORTH, OVER SOUTHERN OREGON/IDAHO, BUT MOST RECENT RUNS IS BRINGING IT FARTHER SOUTH ACROSS NORTHERN AND CENTRAL NEVADA. THE EC HAS CONSISTENTLY BEEN BRINGING THE JET INTO CENTRAL CA/NV, BUT THE JET STRUCTURE IS NOT AS FAVORABLE FOR LARGE SCALE LIFT IN THE LATEST RUNS. THE OTHER PROBLEM IS THIS SYSTEM IS LACKING ORGANIZATION AND DYNAMICS BY THE TIME IT REACHES THE SIERRA AND NORTHWEST NEVADA, SO WILL CONTINUE WITH JUST CHANCES FOR PRECIPITATION UNTIL CONFIDENCE INCREASES. FOLLOWING THIS WAVE, THE RIDGE OF HIGH PRESSURE REBUILDS OVER THE WEST COAST AND APPEARS TO REMAIN ANCHORED THERE THROUGHOUT NEXT WEEK. THIS WILL DEFLECT THE STORM TRACK NORTHWARD AND KEEP THE SIERRA AND WESTERN NEVADA DRY. DJ AVIATION... TRANQUIL WEATHER CONDITIONS WITH SCATTERED TO BROKEN MID AND HIGH LEVEL CLOUDS TO CONTINUE THROUGH 00Z THURSDAY. WEST SOUTHWEST WINDS AROUND 25 KTS AT 10K FEET THROUGH THIS EVENING WITH GUSTS UP TO 15 KTS AT VALLEY TERMINALS. FAST MOVING SYSTEM TO IMPACT AREAS MAINLY NORTH OF HIGHWAY 50 WEDNESDAY NIGHT INTO THURSDAY WITH LIGHT SHOWERS AND MODERATE CHANCES FOR MVFR CIGS/VIS. SNOW LEVELS WILL BE BETWEEN 4500-5500 FEET MSL, SO A MIX OF RAIN AND SNOW IS POSSIBLE AT MOST AREA AIRPORTS. ANY ACCUMULATION WILL BE LIMITED DUE TO THE FAST STORM MOTION. WINDS TO INCREASE FRIDAY INTO SATURDAY WITH A SECOND, STRONGER SYSTEM POSSIBLE THIS WEEKEND. 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 CHICAGO/ROMEOVILLE IL
923 PM CST THU JAN 9 2014 .DISCUSSION... 816 PM CST RADAR MOSAIC SHOWS CONTINUED LIGHT SNOW ACROSS MUCH OF THE EASTERN CWA FROM NEAR PONTIAC NORTHEAST TO THE NORTHERN CHICAGO METRO. WARM ASCENT CONTINUES ABOVE WITH ADDITIONAL ASCENT LOOKING TO BE PROVIDED BY AN ELONGATED AREA OF CYCLONIC VORTICITY TRAILING A SHORTWAVE DEPARTING TO THE EAST. ASCENT AHEAD OF SUBTLE WAVE MOVING INTO WEST CENTRAL IL MAY ALSO BE PLAYING A ROLE. RECENT AIRCRAFT SOUNDINGS AND FORECAST RAP SOUNDINGS SHOW THE TOP OF THE MOIST LAYER NEAR -10C SUPPORTING NEEDLE AND COLUMN LIKE CRYSTALS. MAINLY NEEDLES APPEAR TO BE FALLING AT THE OFFICE AT THE MOMENT. THIS FINER CRYSTAL STRUCTURE SUGGESTS MINIMAL ACCUMULATION BUT A COATING TO A TENTH OR TWO IS IS LIKELY UNTIL THIS BETTER ORGANIZED SNOW BAND DEPARTS...WHICH SHOULD OCCUR IN THE NEXT FEW HOURS. HAVE INCREASED POPS FOR THE NEXT FEW HOURS AND ADDED SOME MINIMAL ACCUMULATION TO THE GRIDS. GIVEN THE SNOW FALLING...FREEZING DRIZZLE LOOKS TO HOLD OFF UNTIL LATER THIS EVENING AS THE SNOW DEPARTS AND COLUMN MOISTURE BECOMES MORE SHALLOW LEADING TO A LOWER PERCENTAGE OF ICE IN THE CLOUDS...BUT THIS STILL LOOKS TO BE PATCHY IN COVERAGE IF IT OCCURS. OTHERWISE VSBY LOOKS TO BE REDUCED IN MIST WHICH MAY BE ENOUGH TO PROVIDE SOME SLICK SPOTS ON SOLID SURFACES INTO THE OVERNIGHT BUT DENSE FREEZING/ACCUMULATING FOG IS NOT EXPECTED AT THIS TIME. MDB //PREV DISCUSSION... 339 PM CST MAIN FORECAST CHALLENGES/CONCERNS ARE WITH LIGHT SNOW OR LIGHT FREEZING DRIZZLE POTENTIAL LINGERING INTO THIS EVENING...POTENTIAL FOR FREEZING RAIN OR FREEZING DRIZZLE ONCE AGAIN FRIDAY MORNING...AND THEN A CONTINUED WARM UP WITH ALL RAIN LIKELY FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. CONCERNS IN THE NEAR TERM REMAIN WITH ONGOING LIGHT SNOW...AS WELL AS A TRANSITION TO EITHER LIGHT SNOW OR LIGHT FREEZING DRIZZLE LATE THIS AFTERNOON INTO THE EARLY EVENING. LATEST RADAR IMAGERY DEPICTING ONLY LIGHT RETURNS ON RADAR...WITH SURFACE OBS STILL REPORTING ALL SNOW ACROSS THE AREA. THIS SNOW HAS BEEN IN RESPONSE TO A SHORT WAVE TROUGH LIFTING EAST/NORTHEAST ACROSS THE REGION...AS WELL AS A WAA WING SWINGING A SWATH PRECIP ACROSS MAINLY THE SOUTHEAST TWO THIRDS OF THE CWA. AN OVERALL DIMINISHING TREND AS BEEN OBSERVED THIS PAST HOUR AND EXPECT THIS TO CONTINUE LATE THIS AFTERNOON...AS WITH THIS WEAK FORCING FURTHER WEAKENING WHILE SHIFTING EAST OUT OF THE AREA. SNOWFALL THIS PAST AFTERNOON HAS BEEN FROM A DUSTING UP TO A HALF INCH...VIA REPORTS FROM FACEBOOK/TWITTER...AND WOULD EXPECT AT MOST A COUPLE OF TENTHS OF AN INCH OF ADDITIONAL SNOWFALL THIS AFTERNOON. ALTHOUGH THERE STILL REMAINS CONCERNS FOR A TRANSITION OVER TO FREEZING DRIZZLE LATE THIS AFTERNOON...CONCERNS FOR ANY LONG DURATION/PREVAILING FREEZING DRIZZLE ARE BEGINNING TO LESSEN. AS DEEPER MOISTURE CONTINUES TO STREAM OVER THE REGION...PRECIP TYPE REMAINS ALL SNOW AT THIS HOUR. THROUGH THE 00Z TIME FRAME IT DOES APPEAR THAT THIS DEEPER MOISTURE IS LOSS...BUT STILL ON THE LOWER THRESHOLD FOR CRYSTALS TO BE PRESENT AND THUS FOR SNOW FOR MOST AREAS. 00Z AND BEYOND...CONTINUED LOSS OF THIS MOISTURE WILL OCCUR AND ITS DURING THIS TIME FRAME THAT I THINK THERE WILL BE THE POTENTIAL FOR LIGHT FREEZING DRIZZLE. ALTHOUGH...LATEST GUIDANCE IN FAIR AGREEMENT WITH THE BETTER LIFT/OMEGA IN THE LOWER LEVEL MOIST LAYER TO BEGIN SHIFTING EAST OF THE CWA ALSO DURING THIS TIME. SO DO FEEL THAT THERE IS STILL POTENTIAL FOR LIGHT FREEZING DRIZZLE THIS EVENING...THINK ITS A SMALL WINDOW FOR THIS OPPORTUNITY BEFORE ALL LIFT DEPARTS. HAVE TRENDED THE GRIDS THIS WAY FOR THIS EVENING...BUT DID LEAVE PATCHY FREEZING DRIZZLE IN OVERNIGHT FOR MOST AREAS. LATEST SATELLITE IMAGERY/OBSERVATIONS DEPICTING LOW LEVEL MOISTURE STILL WORKING ITS WAY NORTH ACROSS THE REGION. IN THE HIGHLY SATURATED LOWER LEVELS...CONCERNED THAT THIS PATCHY LIGHT FREEZING DRIZZLE COULD STILL OCCUR. AM NOT EXPECTING MUCH IN TERMS OF ICE ACCUMULATION...BUT CANNOT RULE OUT ISOLATED SLIPPERY CONDITIONS TO DEVELOP. TEMPERATURES LATE THIS AFTERNOON/EARLY EVENING WILL BE OUR LOWS FOR THE NIGHT...AS STRONG WAA CONTINUES TONIGHT WITH RISING TEMPS EXPECTED TONIGHT INTO FRIDAY MORNING. DESPITE WARMING TEMPS THROUGH EARLY FRIDAY MORNING...SURFACE TEMPS WILL STILL BE AT OR JUST BELOW FREEZING THROUGH MID LATE MORNING. ASCENT WILL BE ON THE INCREASE ON FRIDAY AS A STRONG MID/UPPER LEVEL TROUGH SHIFTS EAST ACROSS THE CENTRAL PLAINS. WITH THERMAL PROFILES DURING THIS TIME SUPPORTIVE OF ALL LIQUID...AM STILL CONCERNED THAT A BRIEF PERIOD OF FREEZING RAIN COULD OCCUR. THE QUESTIONS WILL BE IF FORCING/PRECIP RETURNS SOON ENOUGH BEFORE TEMPS RISE ABOVE FREEZING. ALTHOUGH DO FEEL THAT THIS BETTER PRECIP AXIS WONT ARRIVE UNTIL TEMPS RISE AT OR ABOVE FREEZING BY THIS MID LATE MORNING PERIOD. IF FREEZING RAIN DOES OCCUR...IT SHOULD BE A NARROW TIME FRAME WITH THE WEST/SOUTHWEST AREAS IN A MORE PREFERRED LOCATION IN THE MORNING...AND POSSIBLY FOR THE FAR NORTHWEST CWA THROUGH MID DAY. CONTINUED WARMING CONTINUES INTO THE AFTERNOON WITH ALL RAIN THEN OCCURRING FRIDAY AFTERNOON INTO FRIDAY NIGHT FOR ALL AREAS...WITH THREE QUARTERS OF AN INCH TO ONE INCH POSSIBLE AREA WIDE. LATEST TRENDS HAVE BEEN FOR A QUICKER TRANSITION BACK TOWARDS SNOW LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING...WITH ALL SNOW LIKELY THEN SATURDAY BEFORE THIS PRECIP EXITS. ALTHOUGH ANY LINGERING SNOW SHOULD BE ON THE LIGHT SIDE...AND DONT ANTICIPATE ANY ADDITIONAL SNOW ACCUMULATION. RODRIGUEZ && .HYDROLOGY...339 PM CST ALSO OF INTEREST THIS FORECAST CONTINUE TO BE WITH HYDROLOGIC ISSUES...WITH A WARMER AND MORE MOIST AIR MASS MOVING NORTH ACROSS THE REGION TONIGHT THROUGH FRIDAY. THIS WILL ALLOW FOR A TRANSITION TO ALL RAIN BY MID DAY FRIDAY...CONTINUING INTO EARLY SATURDAY MORNING. RAINFALL TOTALS OF THREE QUARTERS OF AN INCH TO ONE INCH ARE POSSIBLE AREA WIDE FROM FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. CONCERNS WITH THE WARM UP...RAINFALL...FROZEN GROUND WITH CURRENT SNOWPACK IN PLACE COULD ALL RESULT IN RISES IN AREA RIVERS/STREAMS/CREEKS AS WELL AS POTENTIAL FOR FLOODING AND ICE JAM FLOODING. CONFIDENCE IS NOT TOO HIGH WITH REGARDS TO THE EXTENT OF THE SNOWMELT...NONETHELESS...THE PREVIOUSLY MENTIONED CONCERNS WARRANT CONTINUED CLOSE MONITOR OF THIS SITUATION INTO THE WEEKEND. FOR MORE INFORMATION ON THIS FLOOD POTENTIAL SEE THE HYDROLOGIC OUTLOOK ISSUED EARLIER THIS AFTERNOON...ESF. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * SOME LIGHT SNOW TRANSITIONING OVER TO LIGHT FOG LATE THIS EVENING. * CIGS TRENDING DOWN TO IFR BY 05 UTC. * POTENTIAL FOR FOG...POSSIBLY DENSE LATER IN THE DAY FRIDAY. * RAIN OVERSPREADING THE TERMINALS AGAIN FRIDAY AFTERNOON. KJB //DISCUSSION...UPDATED 00Z... A RATHER MESSY WEATHER PERIOD IS IN STORE ACROSS THE TAF SITES. IN THE NEAR TERM...THERE WILL CONTINUE TO BE LIGHT SNOW PERIODICALLY THROUGH AROUND 02 UTC...WITH ONLY MINIMAL VIS REDUCTIONS. CIGS WILL BE ON A DOWNWARD TREND INTO THE IFR CATEGORY...LIKELY BE MID EVENING AS LOW LEVEL MOISTURE CONTINUES TO INCREASE ACROSS THE AREA. THE EXACT TIMING OF THE ONSET OF THESE IFR CIGS REMAIN A BIT UNCERTAIN...BUT IT WOULD APPEAR THAT THEY WOULD BE IN PLACE BY MID TO LATE EVENING. SOME PATCHY AREAS OF -FZDZ MAY ALSO OCCUR THIS EVENING. HOWEVER...ANY ACTIVITY LOOKS TO REMAIN PATCHY INTO THE OVERNIGHT HOURS. AN AREA OF LOW PRESSURE IS EXPECTED TO LIFT NORTHEASTWARD ACROSS EASTERN IOWA FRIDAY AFTERNOON...AND ACROSS SOUTHERN WISCONSIN BY FRIDAY EVENING. THIS SYSTEM WILL LIFT A WARM FRONT NORTHWARD ACROSS NORTHERN ILLINOIS AND NORTHWESTERN INDIANA DURING THE AFTERNOON FRIDAY. A LARGE SURGE OF MOISTURE IS EXPECTED WITH THIS FRONT...AND THIS COULD SET THE STAGE FOR AREAS OF FOG...AND EVENTUALLY RAIN ACROSS THE AREA FRIDAY AFTERNOON AND EVENING. IT REMAINS A BIT UNCLEAR ON HOW DENSE THE FOG WILL BE...BUT WITH THE AMOUNT OF MOISTURE SURGING NORTHWARD OVER THE SNOW COVERED GROUND...THE POTENTIAL EXISTS TO SEE SOME VERY LOW VIS AND CIGS FOR A PERIOD AS THE WARM FRONT APPROACHES THE AREA FRIDAY AFTERNOON. IT APPEARS THE PRIM TIME FOR THIS WOULD BE AFTER 19 UTC THROUGH LATE AFTERNOON/EARLY EVENING. THE RAIN APPEARS THAT IT WILL ONSET AROUND 22 UTC AND CONTINUE DURING THE EVENING. IFR CIGS LOOK TO LINGER THROUGHOUT THE EVENT. WINDS WILL START OUT FRIDAY OUT OF THE SOUTH-SOUTHEAST...THEN BECOME NEARLY DUE SOUTH BY LATE AFTERNOON/EARLY EVENING IN THE WAKE OF THE WARM FRONT. WIND SPEEDS WILL ALSO INCREASE TO AROUND 15 KT BY FRIDAY EVENING AS THE SURFACE LOW TRACKS ACROSS FAR NORTHWESTERN ILLINOIS. KJB //ORD AND MDW CONFIDENCE...UPDATED 03Z... * MEDIUM-HIGH CONFIDENCE IN SOME LIGHT FOG CONTINUING OVERNIGHT. * LOW CONFIDENCE ON -FZDZ POTENTIAL THIS EVENING/OVERNIGHT. * MEDIUM CONFIDENCE IN RAIN TIMING FRIDAY. * MEDIUM CONFIDENCE IN VSBY TRENDS ON FRIDAY. * MEDIUM-HIGH CONFIDENCE IN CIG TRENDS...LOW-MEDIUM CONFIDENCE IN TIMING. KJB //OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z... SATURDAY...GUSTY WEST WINDS WITH A CHANCE OF -SN WITH IFR/MVFR POSSIBLE EARLY. VFR/WX NIL OVERNIGHT. SUNDAY...GUSTY SOUTH WINDS. VFR/WX NIL EARLY. SLIGHT CHANCE OF RAIN OR SNOW WITH MVFR POSSIBLE OVERNIGHT. MONDAY...VFR/WX NIL. TUESDAY...SLIGHT CHANCE OF SNOW. MVFR POSSIBLE. WEDNESDAY...VFR/WX NIL. KJB && .MARINE... 219 PM CST BROAD SURFACE RIDGE ALONG THE EASTERN SEABOARD STRETCHES FROM QUEBEC SOUTH THROUGH THE CAROLINAS...WITH AN INFLUENCING REMAINING ACROSS THE WESTERN GREAT LAKES THIS AFTERNOON. THE LARGEST INFLUENCE HAS BEEN THE LACK OF A GRADIENT...WHICH HAS RESULTED IN WINDS BEING MUCH LIGHTER THAN EARLIER ANTICIPATED. THUS HAVE SLOWED THE WIND SPEEDS DOWN...AND ALSO HAS RESULTED IN WINDS REMAINING MORE SOUTHEASTERLY. A BOUNDARY WAS LIFTING NORTH ACROSS THE OHIO VALLEY...AND WILL LIKELY REACH THE SOUTHERN PORTIONS OF THE LAKE OVERNIGHT THEN ALLOW WINDS TO TURN MORE SOUTHERLY FOR THE LAKE. OVERNIGHT INTO FRIDAY GUIDANCE CONTINUES TO SUGGEST THE LACK OF A GRADIENT WILL REMAIN WEST OF LAKE MICHIGAN...THEN THE CHANNEL OF BETTER WINDS WILL EVENTUALLY SLIDE EAST/SOUTHEAST ACROSS THE LAKE FRIDAY AFTERNOON/EVENING. SFC FLOW WILL REMAIN SOUTHERLY...WITH SPEEDS GENERALLY AROUND 20 TO 30 KT. AT THIS TIME IT APPEARS HAZARDOUS WINDS FOR SMALL CRAFT WILL DEVELOP AROUND THIS TIME AS WELL. THEN THE FOCUS FOR THE WEEKEND WILL BE ON A DEVELOPING LOW PRESSURE SYSTEM THAT IS EXPECTED TO DEVELOP ACROSS THE SOUTHERN PLAINS...WHICH WILL EVENTUALLY LIFT NORTHEAST ACROSS LATE SATURDAY MORNING. THE GRADIENT WILL TIGHTEN SATURDAY EVENING...POSSIBLY BRINGING SOME OCCASIONAL GUSTS TO 30 KT. THEN THE GRADIENT BEGINS TO SLACKEN OFF THROUGH EARLY SUNDAY. YET ANOTHER LOW PRESSURE SYSTEM IS EXPECTED TO SLIDE EAST ACROSS THE UPPER MIDWEST SUN AFTN...WITH THE GRADIENT TIGHTENING YET AGAIN FOR LAKE MICHIGAN. CURRENT FORECAST GUIDANCE INDICATES THE POSSIBILITY OF OCCASIONAL GALE FORCE GUSTS FOR THE OPEN WATERS SUN LATE AFTN/EVE. THE PATTERN REMAINS RELATIVELY ACTIVE FOR EARLY NEXT WEEK...WITH ANOTHER LOW PRESSURE SYSTEM POISED TO SLIDE SOUTHEAST FROM THE UPPER MIDWEST INTO THE GREAT LAKES. THE GRADIENT WILL ONCE AGAIN TIGHTEN...WITH WINDS EVENTUALLY TURNING WEST/NORTHWESTERLY TUE NGT/WED. THE AMOUNT OF ICE REMAINS HIGH ACROSS NEARSHORE WATERS AS SEEN IN WEBCAMS AND SATELLITE IMAGERY. THUS WAVES WILL BE OMITTED FROM THE NEARSHORE FORECAST. BEACHLER && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
818 PM CST THU JAN 9 2014 .DISCUSSION... 816 PM CST RADAR MOSAIC SHOWS CONTINUED LIGHT SNOW ACROSS MUCH OF THE EASTERN CWA FROM NEAR PONTIAC NORTHEAST TO THE NORTHERN CHICAGO METRO. WARM ASCENT CONTINUES ABOVE WITH ADDITIONAL ASCENT LOOKING TO BE PROVIDED BY AN ELONGATED AREA OF CYCLONIC VORTICITY TRAILING A SHORTWAVE DEPARTING TO THE EAST. ASCENT AHEAD OF SUBTLE WAVE MOVING INTO WEST CENTRAL IL MAY ALSO BE PLAYING A ROLE. RECENT AIRCRAFT SOUNDINGS AND FORECAST RAP SOUNDINGS SHOW THE TOP OF THE MOIST LAYER NEAR -10C SUPPORTING NEEDLE AND COLUMN LIKE CRYSTALS. MAINLY NEEDLES APPEAR TO BE FALLING AT THE OFFICE AT THE MOMENT. THIS FINER CRYSTAL STRUCTURE SUGGESTS MINIMAL ACCUMULATION BUT A COATING TO A TENTH OR TWO IS IS LIKELY UNTIL THIS BETTER ORGANIZED SNOW BAND DEPARTS...WHICH SHOULD OCCUR IN THE NEXT FEW HOURS. HAVE INCREASED POPS FOR THE NEXT FEW HOURS AND ADDED SOME MINIMAL ACCUMULATION TO THE GRIDS. GIVEN THE SNOW FALLING...FREEZING DRIZZLE LOOKS TO HOLD OFF UNTIL LATER THIS EVENING AS THE SNOW DEPARTS AND COLUMN MOISTURE BECOMES MORE SHALLOW LEADING TO A LOWER PERCENTAGE OF ICE IN THE CLOUDS...BUT THIS STILL LOOKS TO BE PATCHY IN COVERAGE IF IT OCCURS. OTHERWISE VSBY LOOKS TO BE REDUCED IN MIST WHICH MAY BE ENOUGH TO PROVIDE SOME SLICK SPOTS ON SOLID SURFACES INTO THE OVERNIGHT BUT DENSE FREEZING/ACCUMULATING FOG IS NOT EXPECTED AT THIS TIME. MDB && .PREV DISCUSSION... 339 PM CST MAIN FORECAST CHALLENGES/CONCERNS ARE WITH LIGHT SNOW OR LIGHT FREEZING DRIZZLE POTENTIAL LINGERING INTO THIS EVENING...POTENTIAL FOR FREEZING RAIN OR FREEZING DRIZZLE ONCE AGAIN FRIDAY MORNING...AND THEN A CONTINUED WARM UP WITH ALL RAIN LIKELY FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. CONCERNS IN THE NEAR TERM REMAIN WITH ONGOING LIGHT SNOW...AS WELL AS A TRANSITION TO EITHER LIGHT SNOW OR LIGHT FREEZING DRIZZLE LATE THIS AFTERNOON INTO THE EARLY EVENING. LATEST RADAR IMAGERY DEPICTING ONLY LIGHT RETURNS ON RADAR...WITH SURFACE OBS STILL REPORTING ALL SNOW ACROSS THE AREA. THIS SNOW HAS BEEN IN RESPONSE TO A SHORT WAVE TROUGH LIFTING EAST/NORTHEAST ACROSS THE REGION...AS WELL AS A WAA WING SWINGING A SWATH PRECIP ACROSS MAINLY THE SOUTHEAST TWO THIRDS OF THE CWA. AN OVERALL DIMINISHING TREND AS BEEN OBSERVED THIS PAST HOUR AND EXPECT THIS TO CONTINUE LATE THIS AFTERNOON...AS WITH THIS WEAK FORCING FURTHER WEAKENING WHILE SHIFTING EAST OUT OF THE AREA. SNOWFALL THIS PAST AFTERNOON HAS BEEN FROM A DUSTING UP TO A HALF INCH...VIA REPORTS FROM FACEBOOK/TWITTER...AND WOULD EXPECT AT MOST A COUPLE OF TENTHS OF AN INCH OF ADDITIONAL SNOWFALL THIS AFTERNOON. ALTHOUGH THERE STILL REMAINS CONCERNS FOR A TRANSITION OVER TO FREEZING DRIZZLE LATE THIS AFTERNOON...CONCERNS FOR ANY LONG DURATION/PREVAILING FREEZING DRIZZLE ARE BEGINNING TO LESSEN. AS DEEPER MOISTURE CONTINUES TO STREAM OVER THE REGION...PRECIP TYPE REMAINS ALL SNOW AT THIS HOUR. THROUGH THE 00Z TIME FRAME IT DOES APPEAR THAT THIS DEEPER MOISTURE IS LOSS...BUT STILL ON THE LOWER THRESHOLD FOR CRYSTALS TO BE PRESENT AND THUS FOR SNOW FOR MOST AREAS. 00Z AND BEYOND...CONTINUED LOSS OF THIS MOISTURE WILL OCCUR AND ITS DURING THIS TIME FRAME THAT I THINK THERE WILL BE THE POTENTIAL FOR LIGHT FREEZING DRIZZLE. ALTHOUGH...LATEST GUIDANCE IN FAIR AGREEMENT WITH THE BETTER LIFT/OMEGA IN THE LOWER LEVEL MOIST LAYER TO BEGIN SHIFTING EAST OF THE CWA ALSO DURING THIS TIME. SO DO FEEL THAT THERE IS STILL POTENTIAL FOR LIGHT FREEZING DRIZZLE THIS EVENING...THINK ITS A SMALL WINDOW FOR THIS OPPORTUNITY BEFORE ALL LIFT DEPARTS. HAVE TRENDED THE GRIDS THIS WAY FOR THIS EVENING...BUT DID LEAVE PATCHY FREEZING DRIZZLE IN OVERNIGHT FOR MOST AREAS. LATEST SATELLITE IMAGERY/OBSERVATIONS DEPICTING LOW LEVEL MOISTURE STILL WORKING ITS WAY NORTH ACROSS THE REGION. IN THE HIGHLY SATURATED LOWER LEVELS...CONCERNED THAT THIS PATCHY LIGHT FREEZING DRIZZLE COULD STILL OCCUR. AM NOT EXPECTING MUCH IN TERMS OF ICE ACCUMULATION...BUT CANNOT RULE OUT ISOLATED SLIPPERY CONDITIONS TO DEVELOP. TEMPERATURES LATE THIS AFTERNOON/EARLY EVENING WILL BE OUR LOWS FOR THE NIGHT...AS STRONG WAA CONTINUES TONIGHT WITH RISING TEMPS EXPECTED TONIGHT INTO FRIDAY MORNING. DESPITE WARMING TEMPS THROUGH EARLY FRIDAY MORNING...SURFACE TEMPS WILL STILL BE AT OR JUST BELOW FREEZING THROUGH MID LATE MORNING. ASCENT WILL BE ON THE INCREASE ON FRIDAY AS A STRONG MID/UPPER LEVEL TROUGH SHIFTS EAST ACROSS THE CENTRAL PLAINS. WITH THERMAL PROFILES DURING THIS TIME SUPPORTIVE OF ALL LIQUID...AM STILL CONCERNED THAT A BRIEF PERIOD OF FREEZING RAIN COULD OCCUR. THE QUESTIONS WILL BE IF FORCING/PRECIP RETURNS SOON ENOUGH BEFORE TEMPS RISE ABOVE FREEZING. ALTHOUGH DO FEEL THAT THIS BETTER PRECIP AXIS WONT ARRIVE UNTIL TEMPS RISE AT OR ABOVE FREEZING BY THIS MID LATE MORNING PERIOD. IF FREEZING RAIN DOES OCCUR...IT SHOULD BE A NARROW TIME FRAME WITH THE WEST/SOUTHWEST AREAS IN A MORE PREFERRED LOCATION IN THE MORNING...AND POSSIBLY FOR THE FAR NORTHWEST CWA THROUGH MID DAY. CONTINUED WARMING CONTINUES INTO THE AFTERNOON WITH ALL RAIN THEN OCCURRING FRIDAY AFTERNOON INTO FRIDAY NIGHT FOR ALL AREAS...WITH THREE QUARTERS OF AN INCH TO ONE INCH POSSIBLE AREA WIDE. LATEST TRENDS HAVE BEEN FOR A QUICKER TRANSITION BACK TOWARDS SNOW LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING...WITH ALL SNOW LIKELY THEN SATURDAY BEFORE THIS PRECIP EXITS. ALTHOUGH ANY LINGERING SNOW SHOULD BE ON THE LIGHT SIDE...AND DONT ANTICIPATE ANY ADDITIONAL SNOW ACCUMULATION. RODRIGUEZ && .HYDROLOGY... 339 PM CST ALSO OF INTEREST THIS FORECAST CONTINUE TO BE WITH HYDROLOGIC ISSUES...WITH A WARMER AND MORE MOIST AIR MASS MOVING NORTH ACROSS THE REGION TONIGHT THROUGH FRIDAY. THIS WILL ALLOW FOR A TRANSITION TO ALL RAIN BY MID DAY FRIDAY...CONTINUING INTO EARLY SATURDAY MORNING. RAINFALL TOTALS OF THREE QUARTERS OF AN INCH TO ONE INCH ARE POSSIBLE AREA WIDE FROM FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. CONCERNS WITH THE WARM UP...RAINFALL...FROZEN GROUND WITH CURRENT SNOWPACK IN PLACE COULD ALL RESULT IN RISES IN AREA RIVERS/STREAMS/CREEKS AS WELL AS POTENTIAL FOR FLOODING AND ICE JAM FLOODING. CONFIDENCE IS NOT TOO HIGH WITH REGARDS TO THE EXTENT OF THE SNOWMELT...NONETHELESS...THE PREVIOUSLY MENTIONED CONCERNS WARRANT CONTINUED CLOSE MONITOR OF THIS SITUATION INTO THE WEEKEND. FOR MORE INFORMATION ON THIS FLOOD POTENTIAL SEE THE HYDROLOGIC OUTLOOK ISSUED EARLIER THIS AFTERNOON...ESF. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 00Z... * SOME LIGHT SNOW AND LIGHT FOG EARLY THIS EVENING. * STILL A SLIGHT CHANCE FOR SOME PATCHY FREEZING DRIZZLE THIS EVENING. * CIGS TRENDING DOWN TO IFR BY MID TO LATE EVENING. * POTENTIAL FOR FOG...POSSIBLY DENSE LATER IN THE DAY FRIDAY. * RAIN OVERSPREADING THE TERMINALS AGAIN FRIDAY AFTERNOON. KJB //DISCUSSION...UPDATED 00Z... A RATHER MESSY WEATHER PERIOD IS IN STORE ACROSS THE TAF SITES. IN THE NEAR TERM...THERE WILL CONTINUE TO BE LIGHT SNOW PERIODICALLY THROUGH AROUND 02 UTC...WITH ONLY MINIMAL VIS REDUCTIONS. CIGS WILL BE ON A DOWNWARD TREND INTO THE IFR CATEGORY...LIKELY BE MID EVENING AS LOW LEVEL MOISTURE CONTINUES TO INCREASE ACROSS THE AREA. THE EXACT TIMING OF THE ONSET OF THESE IFR CIGS REMAIN A BIT UNCERTAIN...BUT IT WOULD APPEAR THAT THEY WOULD BE IN PLACE BY MID TO LATE EVENING. SOME PATCHY AREAS OF -FZDZ MAY ALSO OCCUR THIS EVENING. HOWEVER...ANY ACTIVITY LOOKS TO REMAIN PATCHY INTO THE OVERNIGHT HOURS. AN AREA OF LOW PRESSURE IS EXPECTED TO LIFT NORTHEASTWARD ACROSS EASTERN IOWA FRIDAY AFTERNOON...AND ACROSS SOUTHERN WISCONSIN BY FRIDAY EVENING. THIS SYSTEM WILL LIFT A WARM FRONT NORTHWARD ACROSS NORTHERN ILLINOIS AND NORTHWESTERN INDIANA DURING THE AFTERNOON FRIDAY. A LARGE SURGE OF MOISTURE IS EXPECTED WITH THIS FRONT...AND THIS COULD SET THE STAGE FOR AREAS OF FOG...AND EVENTUALLY RAIN ACROSS THE AREA FRIDAY AFTERNOON AND EVENING. IT REMAINS A BIT UNCLEAR ON HOW DENSE THE FOG WILL BE...BUT WITH THE AMOUNT OF MOISTURE SURGING NORTHWARD OVER THE SNOW COVERED GROUND...THE POTENTIAL EXISTS TO SEE SOME VERY LOW VIS AND CIGS FOR A PERIOD AS THE WARM FRONT APPROACHES THE AREA FRIDAY AFTERNOON. IT APPEARS THE PRIM TIME FOR THIS WOULD BE AFTER 19 UTC THROUGH LATE AFTERNOON/EARLY EVENING. THE RAIN APPEARS THAT IT WILL ONSET AROUND 22 UTC AND CONTINUE DURING THE EVENING. IFR CIGS LOOK TO LINGER THROUGHOUT THE EVENT. WINDS WILL START OUT FRIDAY OUT OF THE SOUTH-SOUTHEAST...THEN BECOME NEARLY DUE SOUTH BY LATE AFTERNOON/EARLY EVENING IN THE WAKE OF THE WARM FRONT. WIND SPEEDS WILL ALSO INCREASE TO AROUND 15 KT BY FRIDAY EVENING AS THE SURFACE LOW TRACKS ACROSS FAR NORTHWESTERN ILLINOIS. KJB //ORD AND MDW CONFIDENCE...UPDATED 00Z... * MEDIUM-HIGH CONFIDENCE IN SOME -SN AND LIGHT FOG CONTINUING INTO THE EARLY EVENING. * LOW CONFIDENCE ON -FZDZ POTENTIAL THIS EVENING/OVERNIGHT. * MEDIUM CONFIDENCE IN RAIN TIMING FRIDAY. * MEDIUM CONFIDENCE IN VSBY TRENDS ON FRIDAY. * MEDIUM-HIGH CONFIDENCE IN CIG TRENDS...LOW-MEDIUM CONFIDENCE IN TIMING. KJB //OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z... SATURDAY...GUSTY WEST WINDS WITH A CHANCE OF -SN WITH IFR/MVFR POSSIBLE EARLY. VFR/WX NIL OVERNIGHT. SUNDAY...GUSTY SOUTH WINDS. VFR/WX NIL EARLY. SLIGHT CHANCE OF RAIN OR SNOW WITH MVFR POSSIBLE OVERNIGHT. MONDAY...VFR/WX NIL. TUESDAY...SLIGHT CHANCE OF SNOW. MVFR POSSIBLE. WEDNESDAY...VFR/WX NIL. KJB && .MARINE... 219 PM CST BROAD SURFACE RIDGE ALONG THE EASTERN SEABOARD STRETCHES FROM QUEBEC SOUTH THROUGH THE CAROLINAS...WITH AN INFLUENCING REMAINING ACROSS THE WESTERN GREAT LAKES THIS AFTERNOON. THE LARGEST INFLUENCE HAS BEEN THE LACK OF A GRADIENT...WHICH HAS RESULTED IN WINDS BEING MUCH LIGHTER THAN EARLIER ANTICIPATED. THUS HAVE SLOWED THE WIND SPEEDS DOWN...AND ALSO HAS RESULTED IN WINDS REMAINING MORE SOUTHEASTERLY. A BOUNDARY WAS LIFTING NORTH ACROSS THE OHIO VALLEY...AND WILL LIKELY REACH THE SOUTHERN PORTIONS OF THE LAKE OVERNIGHT THEN ALLOW WINDS TO TURN MORE SOUTHERLY FOR THE LAKE. OVERNIGHT INTO FRIDAY GUIDANCE CONTINUES TO SUGGEST THE LACK OF A GRADIENT WILL REMAIN WEST OF LAKE MICHIGAN...THEN THE CHANNEL OF BETTER WINDS WILL EVENTUALLY SLIDE EAST/SOUTHEAST ACROSS THE LAKE FRIDAY AFTERNOON/EVENING. SFC FLOW WILL REMAIN SOUTHERLY...WITH SPEEDS GENERALLY AROUND 20 TO 30 KT. AT THIS TIME IT APPEARS HAZARDOUS WINDS FOR SMALL CRAFT WILL DEVELOP AROUND THIS TIME AS WELL. THEN THE FOCUS FOR THE WEEKEND WILL BE ON A DEVELOPING LOW PRESSURE SYSTEM THAT IS EXPECTED TO DEVELOP ACROSS THE SOUTHERN PLAINS...WHICH WILL EVENTUALLY LIFT NORTHEAST ACROSS LATE SATURDAY MORNING. THE GRADIENT WILL TIGHTEN SATURDAY EVENING...POSSIBLY BRINGING SOME OCCASIONAL GUSTS TO 30 KT. THEN THE GRADIENT BEGINS TO SLACKEN OFF THROUGH EARLY SUNDAY. YET ANOTHER LOW PRESSURE SYSTEM IS EXPECTED TO SLIDE EAST ACROSS THE UPPER MIDWEST SUN AFTN...WITH THE GRADIENT TIGHTENING YET AGAIN FOR LAKE MICHIGAN. CURRENT FORECAST GUIDANCE INDICATES THE POSSIBILITY OF OCCASIONAL GALE FORCE GUSTS FOR THE OPEN WATERS SUN LATE AFTN/EVE. THE PATTERN REMAINS RELATIVELY ACTIVE FOR EARLY NEXT WEEK...WITH ANOTHER LOW PRESSURE SYSTEM POISED TO SLIDE SOUTHEAST FROM THE UPPER MIDWEST INTO THE GREAT LAKES. THE GRADIENT WILL ONCE AGAIN TIGHTEN...WITH WINDS EVENTUALLY TURNING WEST/NORTHWESTERLY TUE NGT/WED. THE AMOUNT OF ICE REMAINS HIGH ACROSS NEARSHORE WATERS AS SEEN IN WEBCAMS AND SATELLITE IMAGERY. THUS WAVES WILL BE OMITTED FROM THE NEARSHORE FORECAST. BEACHLER && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
528 AM CST WED JAN 8 2014 .DISCUSSION... 332 AM CST FORECAST CONCERNS THIS MORNING INCLUDE CONTINUED COLD TEMPERATURES THROUGH THURSDAY MORNING...THE POTENTIAL FOR A LITTLE LIGHT SNOW ACROSS THE FAR SOUTHERN CWA TODAY...THEN ANOTHER CHANCE OF SOME LIGHT SNOW OR MIXED LIGHT SNOW/FREEZING DRIZZLE THURSDAY INTO THURSDAY NIGHT. TEMPERATURES CLIMB ABOVE FREEZING FRIDAY WITH A FAIRLY HIGH PROBABILITY FOR RAIN...PERHAPS BEGINNING AS SOME MIXED PRECIP OR FREEZING RAIN FRIDAY MORNING. WEAK HIGH PRESSURE RIDGE STRETCHES FROM THE NORTHERN PLAINS INTO THE MIDWEST EARLY THIS MORNING...WITH ARCTIC AIR REMAINING IN PLACE ACROSS THE AREA AND A SHARP BAROCLINIC BOUNDARY ALONG THE SOUTH EDGE OF THE HIGH. LIGHT/CALM WINDS AND MAINLY CLEAR SKIES OVER DEEP SNOW COVER HAVE ALLOWED OVERNIGHT TEMPS TO DROP INTO THE -10 TO -15 DEGREE RANGE ROUGHLY NORTH OF I-88...THOUGH WITH WIND CHILLS JUST INTO THE NEGATIVE DOUBLE DIGITS IN A FEW SPOTS. MORE CLOUD COVER ACROSS THE SOUTH NEAR THE BAROCLINIC ZONE HAS KEPT TEMPS JUST ABOVE ZERO THERE. THIS ORIENTATION OF FRONTAL ZONE AND CLOUD COVER WILL CONTINUE FOR ANOTHER 24 HOURS OR SO...KEEPING A FAIRLY LARGE GRADIENT FROM COLDER TEMPS ACROSS FAR NORTHERN IL TO ONLY MODERATELY COLD READINGS IN THE SOUTH. SO ONE MORE DAY OF SINGLE DIGIT ABOVE ZERO HIGHS AND ONE MORE NIGHT OF SUB-ZERO MINS FOR THE NORTHERN COUNTIES REMAINS BEFORE A LITTLE MORE ROBUST MODERATION TAKES HOLD ON THURSDAY. GUIDANCE IN GOOD AGREEMENT WITH TEMPS ACROSS OUR SOUTHERN COUNTIES INTO THURSDAY...WITH A LITTLE SPREAD ACROSS THE NORTH WHERE A BLEND TOWARD THE COLDER OUTPUT WAS USED. ACROSS OUR FAR SOUTHERN COUNTIES...MODELS REMAIN IN VERY GOOD AGREEMENT IN DEVELOPING A NARROW SWATH OF LIGHT SNOW BY THIS AFTERNOON...GENERALLY SOUTH OF THE STREATOR-KANKAKEE-DE MOTTE AREAS. PRECIPITATION POTENTIAL WILL BE FOCUSED ALONG THE AFOREMENTIONED BAROCLINIC ZONE AS A PAIR OF MID-LEVEL SHORT WAVES APPROACH TODAY... WITH GUIDANCE DEPICTING AN AREA OF MODERATE FRONTOGENETIC FORCING MOST NOTABLE IN THE 850-800MB LAYER. A LITTLE WEAKLY NEGATIVE EPV NOTED ABOVE THE F-GEN LAYER INITIALLY FROM 800-750MB...THOUGH THIS DOES NOT APPEAR TO PERSIST ONCE THE COLUMN BECOMES MORE SATURATED. ISENTROPIC ASCENT IS FAIRLY WEEK WITH MOST OF THE LIFT PROVIDED BY AGEOSTROPHIC RESPONSE TO THE F-GEN...WITH LOW CONDENSATION PRESSURE DEFICITS LIMITED TO SAME NARROW SWATH AS SEEN IN THE 280-285 K SURFACES. OVERALL...FORCING IS NOT TOO IMPRESSIVE WITH THIS DISTURBANCE WITH WEAK OMEGA WHICH IS GENERALLY CENTERED BELOW BETTER CRYSTAL/FLAKE GROWTH TEMPERATURE LAYER ALOFT. QPF LIMITED TO A FEW HUNDREDTHS ACROSS OUR FARTHEST SOUTH TIER OF COUNTIES...WITH NAM/GFS/RAP COBB DATA SUGGESTING SNOW/LIQUID RATIOS OF AROUND 15/1 YIELDING ABOUT A HALF INCH OR LESS OF SNOWFALL THIS AFTERNOON/EARLY EVENING. LIGHT SNOW SHOULD END EARLY IN THE EVENING...AS RESPONSIBLE PAIR OF MID-LEVEL WAVES RACE OFF TO THE EAST...AND SURFACE HIGH PRESSURE BUBBLE ONCE AGAIN BUILDS ACROSS WI/NORTHERN IL. SURFACE HIGH PRESSURE MOVES QUICKLY OFF TO THE EAST OF THE AREA THURSDAY MORNING...WITH LOW LEVEL FLOW BECOMING SOUTH AS ANOTHER SHORT WAVE TROUGH OF PACIFIC ORIGIN PROPAGATES ACROSS THE REGION. THIS BACKED FLOW INDUCES A REGION OF ISENTROPIC ASCENT AND WARM/MOIST ADVECTION WHICH PRODUCES SATURATION AND PRECIPITATION DEVELOPMENT BY THURSDAY AFTERNOON. MODEL FORECAST SOUNDINGS INDICATE THERE MAY BE SOME TROUBLE SATURATING MID-LEVEL ICE NUCLEATION TEMPERATURE LAYER...ESPECIALLY ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. THIS CAUSES SOME UNCERTAINTY IN P-TYPE WITH THE POTENTIAL FOR SOME LIGHT FREEZING RAIN/DRIZZLE TO MIX WITH LIGHT SNOW DURING THE DAY. MODEL SOUNDINGS INDICATE SOMEWHAT DEEPER SATURATION ACROSS THE EASTERN 1/2 OF THE CWA THURSDAY WHICH SUGGESTS A BETTER CHANCE OF SNOW THERE. SNOW/LIQUID RATIOS WILL BE LOWER AS THE AIR MASS MODERATES...WITH PERHAPS A 10/1 OR 12/1 RATIO YIELDING PERHAPS AN INCH OR SO OF SNOW ACROSS OUR SOUTHEAST COUNTIES. MID-LEVELS DRY OUT ACROSS THE AREA THURSDAY EVENING HOWEVER ATOP MOIST LOW LEVELS...WHICH MAY KEEP THE THREAT OF SOME LIGHT FREEZING DRIZZLE AROUND AREA-WIDE THURSDAY NIGHT. AMPLIFICATION OF LARGE-SCALE UPPER TROUGH TAKES PLACE ACROSS THE WESTERN CONUS THURSDAY NIGHT...INCREASING LOW LEVEL SOUTH WINDS ACROSS THE MIDWEST THURSDAY NIGHT INTO SATURDAY. TEMPERATURES LOOK TO RISE ABOVE FREEZING FRIDAY...WITH RAIN DEVELOPING INTO THE REGION BY FRIDAY AFTERNOON. LOWS EARLY FRIDAY WILL BE IN THE 20S ACROSS THE FORECAST AREA...WITH THE POTENTIAL FOR SOME LIGHT PRECIPITATION IN THE FORM OF LIGHT FREEZING RAIN OR DRIZZLE BEFORE CHANGING TO RAIN AS SURFACE TEMPS WARM DURING THE LATE MORNING/MID-DAY HOURS. FAR NORTHERN ILLINOIS NEAR THE WISCONSIN BORDER WILL BE THE LAST TO CLIMB ABOVE FREEZING...AND THUS HAVE PERHAPS THE GREATEST CHANCE OF RECEIVING SOME FREEZING RAIN. THE BULK OF THE MEASURABLE RAIN SHOULD OCCUR LATER FRIDAY AFTERNOON AND NIGHT HOWEVER...WITH TEMPS ABOVE FREEZING. AS HAS BEEN MENTIONED...SNOW MELT AND RAINFALL WILL LIKELY LEAD TO SOME RISES ON AREA RIVERS AND THE POTENTIAL FOR BREAK-UP ICE JAM FLOODING. LONG-RANGE GUIDANCE INDICATES THIS UPPER TROUGH WILL BE PROGRESSIVE WITH ITS ASSOCIATED SURFACE COLD FRONT MOVING ACROSS THE FORECAST AREA EARLY IN THE DAY. MOST OF THE PRECIP OCCURS PRE-FRONTALLY WITH THIS SYSTEM...WITH LITTLE QPF PRODUCED AFTER COLD FROPA. BRIEF SHORT-WAVE RIDGING DEVELOPS SURFACE AND ALOFT SATURDAY NIGHT INTO SUNDAY BEHIND THE DEPARTING SYSTEM...BEFORE ANOTHER PROGRESSIVE UPPER TROUGH APPROACHES LATER SUNDAY NIGHT AND MONDAY. TEMPERATURES REMAIN A BIT ABOVE NORMAL DURING THE PERIOD...WITH SOME LIGHT RAIN/SNOW MIX INDICATED. SEASONABLY/NORMAL COLDER AIR RETURNS BEHIND THE COLD FRONT TUESDAY. RATZER && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * NONE. KREIN //DISCUSSION...UPDATED 12Z... A RIDGE OF HIGH PRESSURE MOVING ACROSS THE AREA WILL KEEP CLEAR SKIES AND LGT/VRBL-CALM WINDS AT THE TERMINALS THROUGH THE LATE THIS MORNING. A WEAK MID LEVEL DISTURBANCE WILL UNDERCUT THE HIGH PRESSURE CROSSING THROUGH CNTRL IL/IN...SPREADING SOME MID LEVEL CLOUDINESS. A REINFORCING AREA OF HIGH PRESSURE BUILDING OUT OF THE NRN PLAINS TOMORROW AFTERNOON WILL KEEP WINDS GENERALLY WLY-NWLY THROUGH THE DAY WITH SPEEDS REMAINING UNDER 10KT. KREIN //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN ALL FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT...SLIGHT CHANCE LIGHT SNOW OR FREEZING DRIZZLE. MVFR LIKELY...IFR POSSIBLE. FRIDAY...WINTRY MIX EARLY...BECOMING ALL RAIN. MVFR/IFR LIKELY. SATURDAY...SLIGHT CHANCE OF RAIN/MVFR EARLY...THEN DRY/VFR. SUNDAY...CHANCE OF SNOW LATE. MVFR POSSIBLE. MONDAY...SLIGHT CHANCE OF SNOW EARLY. MVFR POSSIBLE. TUESDAY...SLIGHT CHANCE OF SNOW. MVFR POSSIBLE. KREIN && .MARINE... 300 AM CST DEEP LOW PRESSURE REMAINS OVER FAR NORTHERN QUEBEC WHILE HIGH PRESSURE EXTENDS FROM THE NORTHERN PLAINS THROUGH THE SOUTHEASTERN CONUS. THE HIGH PRESSURE WILL GRADUALLY BUILD EASTWARD...LEADING TO THE BRISK WEST WINDS GIVING WAY TO LIGHTER AND MORE VARIABLE WINDS AS THE HIGH PRESSURE BUILDS ACROSS LAKE MICHIGAN WEDNESDAY NIGHT. AS THE HIGH MOVES OFF TO THE EAST ON THURSDAY///A TROUGH OF LOW PRESSURE WILL DEVELOP OVER THE CENTRAL PLAINS...LEADING TO INCREASING SOUTHERLY WINDS OVER THE LAKE. WINDS SHOULD INCREASE TO AROUND 30KT BY THURSDAY AS THE GRADIENT TIGHTENS OVER THE LAKE. STRONG SOUTH WINDS WILL COVER THE LAKE UNTIL EARLY SATURDAY WHEN A STRONG COLD FRONT WILL SWEEP ACROSS THE LAKE SHIFTING WINDS TO WESTERLY. KREIN && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 521 AM CST Wed Jan 8 2014 .DISCUSSION... ISSUED 159 AM CST Wed Jan 8 2014 High pressure ridge to the NW and to the SE...but Central Illinois is in a bit of a weak spot of the ridge that will result in some low chance pops for today. Other issues with the forecast are the general warming trend through Day 7...and a couple of precip chances...tonight and into tomorrow... and Friday into the first portion of the weekend. Current weather map is dominated by rather weak sfc systems overall with a deep low NE of Hudson Bay. Deep cold air over the Great Lakes and NE slowly making its way east, with warmer temperatures in the SW. Previously NWrly flow becoming more zonal and will set up todays chances for precip. SHORT TERM...Today and tomorrow... High temps finally making it back to double digits above zero as the airmass shifts once again. Though a southerly component is returning to sfc winds on the back side of the southeastern high in the southern half of the state...pressure gradient in the weak spot in the ridge is all but non existent and the winds will remain light in most locations through tonight. Quasi boundary/weak convergence at the sfc contributing to some weak, albeit persistent frontogenetic forcing for Central Illinois. Locating exactly where this band of snowfall will set up is extraordinarily difficult. HRRR is furthest north...NAM further south and the RUC/RAPP right in the middle. Pops for this afternoon across the nrn half of the CWA as a result with generally light snowfall amounts listed. As the high pressure to the southeast continues to slide to the east...a southerly component returns to the sfc tomorrow and more warm air ushered into the FA. Tonight and into tomorrow, a system will move out of the SW but collide with the colder air in place over Central Illinois and bring another quick chance of snow...with best chances on Thursday. Accumulations should generally be less than an inch. At the end of the snow, as the system comes to an end...ice crystals are lost aloft and FZDZ chances will move into the western half of the state. Overnight tomorrow night the flurry/freezing drizzle chances may linger a bit through the night. LONG TERM...Friday through Tuesday... Temperatures should be climbing above zero across Central Illinois for Friday and into the weekend. Another system moving in Friday will be a bit problematic in the first portion of the day while sfc temps are below freezing and a deep layer of warm air is in place aloft as the precip starts. Should that profile maintain...will be a mix of rain and freezing rain until the temps rebound. After 18z, dominated by rain in ILX CWA. Friday night...will see the best chances for rain...ending from nw to se on Saturday early as the system has slowed considerably in the last 2 synoptic runs. Next major wave aloft has major differences in track and timing...with the ECMWF looking like the prev 00z GFS and tracking the sfc system southeast of the Ohio River Valley. GFS is far enough south that it never impacts the CWA. The new GFS is actually dry, keeping the majority of the energy to the north and just allowing generally warmer temperatures, at least through Day 7, and a drier forecast. && .AVIATION... ISSUED 510 AM CST Wed Jan 8 2014 Main forecast concern will be timing and coverage of light snow as a weak frontal boundary remains across the area with mostly VFR cigs expected thru 22z. Any snows that do develop later this morning out to our west and makes it this far east will have the potential to drop cigs briefly down to MVFR this evening. Otherwise, look for cigs to lower to between 4500-6000 feet by later this morning, with the potential for cigs to lower to 2500-3500 feet in any light snow that may push across a terminal site. The snow threat should exit east of our area after 02z with low VFR cigs expected to prevail overnight. Surface winds will be variable in direction, mostly from the northeast at less than 10 kts today and then gradually veer more into an easterly direction tonight. Smith && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
951 PM EST THU JAN 9 2014 .SYNOPSIS... HIGH PRESSURE BUILDS OVER NEW ENGLAND TONIGHT AS A TROUGH OF LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST. HIGH PRESSURE MOVES OFFSHORE FRIDAY AS A WEAK UPPER LEVEL TROUGH PASSES ACROSS THE MID ATLANTIC. A COLD FRONT APPROACHES FROM THE WEST SATURDAY AND PUSHES THROUGH THE REGION SATURDAY NIGHT. HIGH PRESSURE RETURNS FROM THE WEST SUNDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... THE LATEST SURFACE ANALYSIS INDICATES A ~1038MB SFC HIGH PRESSURE OVER THE NORTHEASTERN US SEABOARD, EXTENDING SE TOWARDS THE MD EASTERN SHORE. LATEST WATER VAPOR SHOWS NICE PV MAX MOVING THROUGH OHIO. THIS IS PUSHING CLOUDS ACROSS INTO THE NORTHERN SECTIONS OF THE CWA BUT ALL PRECIP WITH THIS HAS STAYED TO THE NORTH AND WEST OF THE AREA. ANOTHER AREA OF WARM ADVECTION IS BEGINNING TO DEVELOP TO THE SOUTHWEST OVER THE CAROLINAS. THE HRRR AND RUC BOTH SHOW MOISTURE FROM THIS MOVING NORTH AND MERGING WITH THE SYSTEM MOVING BY TO THE NORTH. THIS WILL BRING THE PRECIP INTO THE WESTERN SECTIONS NEAR SUNRISE. MOST MODEL AGREE ON THAT TIMING OF BETWEEN 09Z AND 12Z. CLOUDS WILL SLOWLY MOVE IN FROM THE WEST AND SOUTH OVERNIGHT. WHILE TEMPERATURES HAD FALLEN QUICKLY THEY HAVE REMAINED NEARLY STEADY THE LAST COUPLE OF HOURS. THINK TEMPERATURES WILL BE STEADY OR SLOWLY RISING THE REST OF THE NIGHT. MODEL THICKNESSES AND BUFKIT SOUNDINGS INDICATE THE POTENTIAL FOR A LIGHT MIX (MAINLY NW A LINE FROM AVC-OFP-BWI) TOWARD FRIDAY MORNING. BASED ON LATEST FORECAST SOUNDINGS, EXPECT LIGHT PRECIP TO BEGIN AS SLEET/IP...BEFORE TRANSITIONING QUICKLY TO FZRA. ANY QPF WILL BE VERY LIGHT (LESS THAN 0.10"). HOWEVER, CONSIDERING THE TIMING OF ANY LGT PCPN COINCIDING WITH THE EARLY PORTION OF THE MORNING RUSH, WILL GO WITH A SHORT DURATION FZRA ADVISORY OVER THE PIEDMONT NW OF RIC METRO. DID ALSO CONSIDER POINTS FARTHER EAST, BUT DECIDED AGAINST ISSUING OVER THE NORTHERN NECK/SALISBURY, AS PCPN LIKELY HOLDS OFF UNTIL LATER FRIDAY MORNING. STILL, COULD SEE PRECIPITATION BEGIN AS A BRIEF PERIOD OF SLEET EVEN OVER THESE AREAS...AND UPDATED HWO REFLECTS THIS THREAT. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... ANY FREEZING PCPN QUICKLY TRANSITIONS AFTER SUNRISE FRIDAY AS TEMPERATURES RISE ABOVE FREEZING FOR ALL AREAS. HIGHS SHOULD RANGE FROM AROUND 40 NW...TO THE LOW/MID 50S SE. CONTINUED TO UNDERCUT GUIDANCE BY A FEW DEGREES OVER THE NW COUNTIES DUE TO THE PRESENCE OF A LOW-LEVEL CAD AND WITH OCCASIONAL LIGHT RA/SHRAS ONGOING THROUGH THE DAY. THE SKY SHOULD REMAIN CLOUDY DUE TO WEAK FLOW AND ABUNDANT MOISTURE BELOW 750MB. TEMPERATURES SHOULD FALL VERY LITTLE FRIDAY NIGHT AS THE SURFACE WARM FRONT LIFTS THROUGH THE AREA...RESULTING IN WIDESPREAD STRATUS. THE TROUGH PRESENTLY TRAVERSING THE INTERMOUNTAIN WEST THIS AFTN WILL PUSH ACROSS THE ROCKIES THROUGH TONIGHT...EVENTUALLY AMPLIFYING ACROSS THE CENTRAL CONUS ON FRI. SUBSEQUENT INCREASINGLY ZONAL FLOW OVER THE WESTERN US EVENTUALLY WILL EJECT THE TROUGH AXIS EAST ACROSS THE APPALACHIANS BY SAT/SAT EVENING. PLENTY OF SPREAD EXISTS AMONGST GEFS/SREF ENSEMBLE GUIDANCE AS WELL AS THE DETERMINISTIC MODELS WITH RESPECT TO TIMING. MODELS APPEAR IN BETTER AGREEMENT WITH QUICKLY SHUNTING THE WARM FRONT NORTHWARD SAT MORNING. THERE IS A HIGH CONFIDENCE OF MEASURABLE RAIN IN THE SAT/SAT EVENING TIME FRAME. DEEP MOISTURE THROUGH 300MB COMBINED WITH STRONG LIFT SHOULD PRODUCE MODERATE TO OCCASIONALLY HEAVY RAINFALL. HOWEVER...QPF SHOULD LARGELY BE 0.75-1.00IN DUE TO THE QUICK MOTION OF THE SYSTEM. TEMPERATURES SHOULD BE VERY MILD AS THE AFOREMENTIONED SURFACE WARM FRONT LIFTS N OF THE LOCAL AREA AND 850MB TEMPERATURE SURGE TO 10-12C. HIGHS HAVE BEEN NUDGED UPWARD SLIGHTLY ONCE AGAIN INTO THE MID 60S FAR NW...65-70 FOR CENTRAL AND EASTERN PORTIONS OF THE AREA. SREF PROBS CONTINUE TO INDICATE A 90% CHANCE OF 2M DEWPOINTS EXCEEDING 60F ACROSS S-CENTRAL/SE VA AND NE NC...AND 09/21Z NAM INDICATES STRONG UPRIGHT FRONTOGENESIS FROM THE SURFACE TO ~750MB (09/00Z ECMWF INDICATES THIS TO A LESSER EXTENT). THIS IS CONSIDERED A LOW PROB AT THIS TIME...BUT THERE IS A POTENTIAL FOR A FORCED LINE OF CONVECTION (RARE BUT NOT UNPRECEDENTED FOR JAN)...GIVEN STRONG SYNOPTIC FLOW (60-65KT 850-700MB LAYER AVG) COMBINED WITH THE AFOREMENTIONED ABUNDANT MOISTURE AND MESOSCALE FORCING. A TRANSITION DAY ON SUNDAY AS UPPER TROUGH PIVOTS OFFSHORE AND QUASI-ZONAL FLOW BRING A CLEARING AND STILL-MILD DAY. HIGHS GENERALLY IN THE 50S TO NEAR 60. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... STAYING CLOSE TO THE 12Z ECMWF FOR THE EXTENDED PERIOD. HI PRES WILL SLIDE OFF THE CST AND OUT TO SEA SUN NGT THRU MON...PROVIDING MSTLY CLEAR/PARTLY TO MOSTLY SUNNY CONDITIONS ACRS THE AREA. LATE MON NGT THRU TUE...THE LATEST ECMWF BRINGS A SRN STREAM LO AND A COLD FRONT TWD/AND ACRS THE AREA LATE MON NGT THRU TUE. AT THIS TIME...HAVE SLGT CHC (20) POPS THEN CHC (30) POPS OVR THE REGION. THE FRONT PUSHES OUT TO SEA TUE EVENG...BUT A SECONDARY BOUNDARY MAY CROSS THE AREA ON WED. HAVE KEPT A DRY FCST FOR WED AT THIS TIME. DRIER AND COOLER WNW FLO FILTERS IN FOR WED NGT THRU THU...AS HI PRES BLDS INTO AND OVR THE REGION. MIN TEMPS WILL RANGE THRU THE 30S MON MORNG...IN THE UPR 30S TO MID 40S TUE MORNG...IN THE 30S WED MORNG...AND IN THE MID 20S TO LWR 30S THU MORNG. MAX TEMPS WILL RANGE FM THE MID 50S TO LWR 60S MON...IN THE 50S TUE...IN THE MID 40S TO LWR 50S WED...AND IN THE 40S THU. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... A LIGHT EASTERLY FLOW WILL GRADUALLY INCREASE MOISTURE INTO THE AREA OVERNIGHT. CLOUDS BEGIN TO DEVELOP BELOW 10K FT AFTER MIDNIGHT AS AN INVERTED TROUGH/COASTAL FRONT DEVELOP TOWARD MORNING PROVIDING SOME LIFT. THE LOCATION OF THIS FRONT WILL AFFECT THE WIND DIRECTION (SE WINDS TO THE EAST OF THE FRONT) AND IMPACT THE CEILING HEIGHT ON FRIDAY. AS THIS FRONT DEVELOPS MID TO LATE MORNING...IT SHOULD SET UP WEST OF ALL THE TAF SITES EXCEPT RIC THROUGH MIDDAY. THUS HAVE IFR LATE MORNING AT RIC BUT MVFR OR BETTER AT THE REST. EVENTUALLY THE FRONT IS EXPECTED TO MOVE SLIGHTLY TO THE WEST OF RIC... IMPROVING CONDS THERE TO MVFR. USED NAM AND GFS SOUNDINGS AND POP GRIDS TO DETERMINE TIMING OF THE PCPN. HAVE IT BEGIN MID TO LATE MORNING BUT STAYING NORTH OF ECG. RAIN DIMINISHES AFT 18Z. THE POTENTIAL FOR FZRA OR PL (BRIEFLY AROUND 12Z FRIDAY) IS MAINLY WEST OF RIC AND ANY THAT OCCURS SHOULD HAVE LITTLE TO NO IMPACT. OUTLOOK...A MORE ORGANIZED FRONTAL SYSTEM APPROACHES THE REGION ON SATURDAY...WITH PERIODS OF RAIN AND WIDESPREAD MVFR/OCNL IFR CONDITIONS AND GUSTY WINDS. LOOK FOR DRY AND VFR SUNDAY AND MONDAY THEN DETERIORATING CONDS ONCE AGAIN AROUND TUESDAY. && .MARINE... DO NOT HAVE ANY HEADLINES IN THE SHORT TERM TNGT THRU FRI NIGHT. HI PRES WILL MOVE OFF THE NEW ENGLAND CST TNGT...AS A TROF OF LO PRES DEVELOPS ALNG THE CAROLINA CST. NE WINDS 10 KT OR LESS THIS EVENG...WILL BECOME ESE FOR TNGT THRU FRI. SE WINDS WILL THEN INCREASE TO NEAR 15 TO 20 KT LATE FRI NGT...THEN BECOME S AND INCREASE TO 15 TO 25 KT AND GUSTY FOR SAT...AS A WARM FRONT LIFTS NWRD THRU THE AREA...FOLLOWED BY THE APPROACH OF A COLD FRONT. SCA FLAGS WILL BE LIKELY FOR STRONG SOUTHERLY WINDS SAT AFTN/SAT NGT...WITH SEAS BUILDING TO 5-9 FT. WINDS BECOME WNW AND REMAIN RATHER STRONG BEHIND THE FRONT SAT NGT INTO SUN AFTN...THEN SETTLE DOWN AND BECOME SW SUN NGT...AS HI PRES BLDS IN THEN MOVES OFFSHR. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...FREEZING RAIN ADVISORY UNTIL 9 AM EST FRIDAY FOR VAZ048-049- 060>069. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...MAM/JAB SHORT TERM...AJZ/MAM LONG TERM...TMG AVIATION...LSA MARINE...TMG
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
635 PM EST THU JAN 9 2014 .AVIATION... //DISCUSSION... A PATTERN OF SNOW WILL SPREAD OVER SE MICHIGAN AHEAD OF A WARM FRONT ORGANIZING OVER THE OHIO VALLEY. UPSTREAM OBSERVATIONS INDICATE HEAVIER SNOW SHOWERS WILL BE CAPABLE OF QUICK IFR VISIBILITY RESTRICTION BEFORE CEILING LOWERS TO IFR TOWARD SUNRISE AS WELL. THESE CONDITIONS WILL BE MORE SOLID FROM PTK SOUTHWARD DURING THE EVENING BEFORE STRATUS ASSOCIATED WITH THE WARM FRONT CATCHES UP TO ALL LOCATIONS AFTER MIDNIGHT. THE POTENTIAL FOR FREEZING DRIZZLE IS HIGHER TOWARD SUNRISE IN THE DTW TO PTK CORRIDOR CLOSER TO THE SURFACE WARM FRONT BUT IT IS POSSIBLE AS FAR NORTH AS MBS JUST WITH LOWER CONFIDENCE THERE. FOR DTW...LIGHT SNOW HAS SPREAD NORTHWARD FROM OHIO AND INDIANA AND WILL LAST THROUGH THE EVENING. THERE IS POTENTIAL FOR A HEAVIER BURST OF LARGE BUT DRY FLAKES CAPABLE OF IFR RESTRICTION AND A QUICK HALF INCH OF ACCUMULATION. COVERAGE AND DURATION OF SUCH ACTIVITY REMAINS IN QUESTION FOR ANY GREATER SNOW ACCUMULATION AT THIS POINT. A FEW HOURS OF FREEZING DRIZZLE IS EXPECTED TO BEGIN TOWARD SUNRISE AND LAST THROUGH LATE MORNING WHEN TEMPERATURE IS ON SCHEDULE TO RISE ABOVE FREEZING. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET THROUGH THE TAF PERIOD. * HIGH CONFIDENCE IN SNOW AS PRECIPITATION TYPE DURING THE EVENING. * MEDIUM CONFIDENCE IN FREEZING DRIZZLE DEVELOPMENT TOWARD SUNRISE FRIDAY. && .PREV DISCUSSION...ISSUED 359 PM EST THU JAN 9 2014/ SHORT TERM... AFTERNOON AND TONIGHT AFTERNOON RADAR COMPOSITE AND SURFACE OBSERVATIONS INDICATE THE SNOW SHOWER PATTERN COMING TOGETHER WITH SOME GUSTO OVER NORTHERN INDIANA AND WESTERN OHIO. THE MID LEVEL SHORT WAVE SHOWN ON WATER VAPOR IMAGERY LOOKS QUITE DYNAMIC AND IS HELPING SHAPE UP THE WARM FRONT OVER THE OHIO VALLEY AT THE SURFACE AND ENHANCING ISENTROPIC LIFT TO THE NORTH OF THE FRONT INTO LOWER MICHIGAN. MODEL CROSS SECTIONS INDICATE THE SHORT WAVE INDUCED DCVA AND ISENTROPIC LIFT OCCURRING IN A LOW STABILITY ENVIRONMENT AND WITH A GENEROUS AMOUNT OF MOISTURE RESULTING IN THE STRONG VERTICAL MOTION RESPONSE. THE TEXTURE OF THE RADAR COMPOSITE EVEN SUGGESTS WEAK CONVECTIVE INSTABILITY ABOVE THE FRONTAL SURFACE, ROUGHLY IN THE 700-500 MB LAYER JUDGING FROM MODEL THETA-E PROFILES. THE LATEST RUNS OF THE NAM AND RAP HAVE A REASONABLE HANDLE ON THE EVOLUTION OF THE PATTERN AS THE WAVE SLIDES JUST SOUTH OF THE OHIO BORDER. THEY SHOW THE MOST INTENSE VERTICAL MOTION OCCURRING ROUGHLY ALONG AND SOUTH OF A LINE FROM HOWELL TO PORT HURON WITH A PEAK INTENSITY OCCURRING AROUND MID EVENING. THIS WILL CONSIST OF A GOOD COMBINATION OF LOW LEVEL ISENTROPIC LIFT AND MID LEVEL SHEARING DEFORMATION FUELED BY SPECIFIC HUMIDITY NEAR 3 G/KG. EXPECT THE RESULT TO BE WIDESPREAD LIGHT SNOW WITH IMBEDDED HEAVIER BURSTS ADDING UP TO ABOUT AN INCH OF ACCUMULATION AS FAR NORTH AS INTERSTATE 69. BOTH COVERAGE AND INTENSITY WILL BE LESS TOWARD THE TRI CITIES AND NORTHERN THUMB AND THEN WILL DIMINISH OVER THE SOUTH AFTER MIDNIGHT. STRONG MID LEVEL SUBSIDENCE TRAILING THE WAVE WILL THEN SET THE STAGE FOR FREEZING DRIZZLE POTENTIAL TOWARD SUNRISE. MODEL SOUNDINGS INDICATE SUBSIDENCE INDUCED MID LEVEL DRYING TAKING PLACE TOWARD 12Z WHICH WILL ELIMINATE ICE CRYSTAL NUCLEATION. THAT WILL LEAVE A FAVORABLE PROFILE FOR FREEZING DRIZZLE FORCED BY WIND SHEAR AND INSTABILITY AT THE TOP OF THE BOUNDARY LAYER/FRONTAL SLOPE. WHILE THE LARGE SCALE ENVIRONMENT IS SUPPORTIVE AND GROUND SURFACES ARE VERY COLD, UNCERTAINTY ON COVERAGE, DURATION, AND INTENSITY IS HIGH ENOUGH TO HOLD OFF ON HEADLINE ISSUANCE AT THIS POINT. OTHERWISE, THE STRONG NONDIURNAL TEMPERATURE TREND WILL HAVE MINS OCCURRING DURING EARLY EVENING FOLLOWED BY RISING TEMPS OVERNIGHT, BUT ONLY INTO THE LOWER AND MID 20S BY SUNRISE FRIDAY. LONG TERM...FRIDAY THROUGH SATURDAY NIGHT MAIN CONCERNS OVER THIS TIME PERIOD IS THE START TIME AND TYPE OF PRECIPITATION...ESPECIALLY FRIDAY AFTERNOON INTO EVENING BEFORE WARMER AIR WORKS UP INTO THE AREA. WEAK RIDGING AHEAD OF THE MAIN UPPER LEVEL TROUGH MOVING ACROSS THE AREA WILL ALLOW FOR A SLIGHT DOWNTURN IN THE PRECIP FRIDAY MORNING BEFORE MORE SUBSTANTIAL PRECIPITATION WORKS IN WITH THE NEXT LOW PRESSURE SYSTEM FRIDAY INTO SATURDAY. 120+ KNOT JET GETS GOING WITH THE LEFT ENTRANCE REGION MOVING OVER THE AREA. THIS JET THEN STRENGTHENS AS IT MOVES TO THE EAST OF THE AREA SATURDAY AFTERNOON. MODELS HAVE FINALLY COME INTO BETTER AGREEMENT ON THE TIMING AND DURATION OF THIS SYSTEM. AS THE LOW TRACKS NORTHEAST ACROSS WISCONSIN AND UPPER MICHIGAN...THIS WILL PULL A WARM FRONT UP THROUGH THE AREA FRIDAY BRINGING MOISTURE AND WARMER AIR TO SE MI. AS WITH THE CASE OF TRANSITIONING PRECIP TYPE THE BIGGEST CAVEAT WILL BE HOW LONG FREEZING DRIZZLE/RAIN LINGERS BEFORE THE WARMER AIR WORKS IN CHANGING PRECIP TO ALL RAIN. THIS TRANSITION DOES APPEAR TO BE OF SHORTER DURATION AS THE LOW LEVEL JET GETS GOING AND PUSHES IN THE WARMER AIR. SOUNDING PROFILES SHOW SATURATED LOW LEVELS WITH DRIER AIR IN THE MID LEVELS SUPPORTIVE OF DRIZZLE WITH THE ONSET OF PRECIP BEFORE MID LEVELS SATURATE. BETTER FORCING AND PRECIP CHANCES HOLD OFF UNTIL SATURDAY EVENING AS THE COLD FRONT APPROACHES. POPS INCREASE FROM 00Z TO 12Z ON SATURDAY WHICH COINCIDES WITH FAVORED ISENTROPIC ASCENT AHEAD OF THE COLD FRONT. PWAT VALUES REMAINED NEAR 3/4 OF AN INCH...WHICH IS GOOD FOR THIS TIME OF YEAR. WITH THE 12Z MODEL RUNS PUSHING THE COLD FRONT THROUGH A LITTLE FASTER...PRECIP AMOUNTS WERE LOWERED A TINY BIT. THE COLD FRONT IS EXPECTED TO EXIT THE AREA EARLY SATURDAY MORNING...BRINGING AN END TO THE HEAVIER PRECIP. SHOWERS WILL LINGER BEHIND THE FRONT BEFORE RIDGING MOVES BACK IN AND TEMPERATURES DROP BACK BELOW FREEZING. TEMPERATURES WERE DROPPED A LITTLE BIT TO TAKE INTO ACCOUNT THE SNOW COVER AND THE FASTER TIMING OF THE COLD FRONT THROUGH THE AREA SATURDAY EVENING. WAA WORKS IN AS STRONG SOUTHERLY FLOW INCREASES BEHIND THE WARM FRONT LATE FRIDAY BEFORE CAA TAKES OVER WITH THE EXITING COLD FRONT SATURDAY AFTERNOON. TEMPERATURES REMAIN ABOVE FREEZING AND STEADY FRIDAY INTO FRIDAY NIGHT BEFORE DROPPING BACK DOWN ONCE AGAIN. SURFACE RIDGING OVER THE GREAT LAKES REGION WILL KEEP SUNDAY MOSTLY DRY. SOUTHWESTERLY WINDS PICK UP ON SUNDAY WITH GUSTS UP TO 25 MPH DURING THE DAY. THERE IS SOME UNCERTAINTY AMONGST MODELS REGARDING PRECIPITATION CHANCES ON MONDAY. THEREFORE...HAVE ONLY KEPT A SLIGHT CHANCE IN THE FORECAST. HOWEVER...THERE LOOKS TO BE BETTER AGREEMENT THAT TUESDAY COULD BRING SOME PRECIP TO THE REGION. 850 MB TEMPS LOOK TO BE COLD ENOUGH TO SUPPORT ALL SNOW FOR PRECIP ON TUESDAY. HIGH TEMPERATURES WILL START OFF ABOVE NORMAL /FORECASTED HIGHS IN THE UPPER 30S/ ON MONDAY AND SLOWLY DECREASE THROUGHOUT THE REMAINDER OF THE WEEK DROPPING TO THE MID 20S BY THURSDAY. LOWS WILL ALSO START OFF ABOVE NORMAL /LOW 30S/ FOR MONDAY NIGHT AND STEADILY DROP INTO THE LOW TEENS /BELOW NORMAL/ BY THURSDAY NIGHT. MARINE... SOUTHERLY FLOW WILL CONTINUE TO INCREASE THROUGH TONIGHT AS HIGH PRESSURE SLIDES TOWARDS THE EAST COAST. LOW PRESSURE APPROACHING FROM THE PLAINS WILL THEN MAINTAIN SOUTHERLY FLOW THROUGH FRIDAY...WITH SPEEDS INCREASING FRIDAY NIGHT AS A WARM FRONT LIFTS UP THROUGH THE GREAT LAKES. SOUTH TO SOUTHEAST WINDS WILL BECOME GUSTY OVER LAKE HURON FRIDAY NIGHT AS THE LOW TRACKS UP THROUGH LAKE MICHIGAN. SUSTAINED SPEEDS LOOK TO RANGE BETWEEN 20 AND 28 KNOTS OVER MUCH OF THE LAKE...HOWEVER WARMER AIR FLOWING OVER THE LAKE SURFACE WILL KEEP STABILITY HIGH AND LIMIT WIND GUSTS TO BELOW GALE FORCE. COLDER AIR WILL POUR INTO THE REGION ON THE BACKSIDE OF THE SYSTEM ON SATURDAY. THE ARRIVAL OF THE COLDER AIR COMBINED WITH A TIGHT SURFACE PRESSURE GRADIENT AND STRONG WINDS ABOVE THE LAKE SURFACE MAY ALLOW GALE FORCE WINDS TO DEVELOP OVER THE CENTRAL PORTION OF LAKE HURON. A GALE WATCH IS NOW IN EFFECT OVER THE CENTRAL PORTION OF THE LAKE ON SATURDAY...INCLUDING SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH. WIND SPEEDS WILL DECREASE SATURDAY NIGHT AND SUNDAY AS HIGH PRESSURE BUILDS BRIEFLY BACK OVER THE AREA. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WATCH...LHZ362-LHZ363-LHZ421-LHZ422-LHZ441-LHZ462...FROM 7 AM SATURDAY TO 7 PM SATURDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....KURIMSKI SHORT TERM...BT LONG TERM....SS/RK/HLO MARINE.......SS/HLO YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1140 PM EST TUE JAN 7 2014 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 329 PM EST TUE JAN 7 2014 DANGEROUSLY COLD AIR WILL FINALLY MOVE OUT OF THE GREAT LAKES REGION AND HIGH TEMPERATURES ON WEDNESDAY WILL BE IN THE TEENS. TEMPERATURES WILL CONTINUE TO MODERATE AND HIGHS ABOVE FREEZING ARE EXPECTED FRIDAY THROUGH MONDAY. SOME RAIN OR FREEZING RAIN MAY ACCOMPANY THE WARM UP FROM LATE FRIDAY INTO EARLY SATURDAY. && .UPDATE... ISSUED AT 832 PM EST TUE JAN 7 2014 WE HAVE FRESHENED UP THE FCST THIS EVENING...MAINLY TO TWEAK TEMPS A BIT AS SOME LOCATIONS HAVE DROPPED BELOW THEIR FCST MINS. TEMP TRENDS HAVE BEEN ALL OVER THE PLACE THIS EVENING ACROSS THE CWFA. THE WARMEST TEMPS HAVE BEEN FOUND ALONG THE LAKESHORE AS EXPECTED. THE NRN INLAND LOCATIONS HAVE REMAINED UP A LITTLE...WHILE THE SRN ROW OF COUNTIES REMAIN NEAR OR SLIGHTLY BELOW ZERO WITHOUT THE INFLUENCE FROM LAKE MICHIGAN. MODEL TRENDS OVERNIGHT ARE ALL OVER THE PLACE ALSO. THE NAM AND GFS WANT TO SLOWLY WARM TEMPS FOR THE MOST PART...WHILE SHORT TERM HI RES GUIDANCE LIKE THE HRRR RUC DROP TEMPS PRETTY GOOD. WE HAVE TO BELIEVE THAT TEMPS SHOULD DROP A LITTLE AS WIND DIMINISH TONIGHT. AREAS THAT POTENTIALLY CLEAR OUT LIKE THE FAR SOUTH WITH LESS INFLUENCE FROM LAKE MICHIGAN WILL HAVE A BETTER CHC OF DROPPING A FEW DEGREES. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT) ISSUED AT 329 PM EST TUE JAN 7 2014 WILL MAKE THE TRANSITION AT THIS TIME FROM WARNINGS TO ADVISORIES AS GRADUAL IMPROVEMENT IN WIND CHILLS AND EXTENT OF SNOW AND BLOWING SNOW WILL BE TAKING PLACE TONIGHT AND WEDNESDAY. WILL DOWNGRADE TO A WINTER WEATHER ADVISORY ALONG THE LAKESHORE PLUS KENT COUNTY FOR A COMBINATION OF LIGHT SNOW SHOWERS AND WIND CHILLS NEAR 10 BELOW. ELSEWHERE WILL DOWNGRADE THE WIND CHILL WARNING TO A WIND CHILL ADVISORY FOR WIND CHILLS OF 10 TO 20 BELOW. THE COLDEST WIND CHILL READINGS FOR TONIGHT SHOULD OCCUR THIS EVENING BEFORE THE WINDS DIMINISH. CURRENT WIND CHILLS HAVE RECOVERED TO 5 TO 15 BELOW DOWNWIND OF LK MI AND TO 20 TO 25 ALONG THE I-94 CORRIDOR. THESE VALUES WILL REMAIN COMMON FOR THE NEXT FEW HOURS BEFORE NUDGING UP A FEW DEGREES. VISIBILITIES AT THE LAKESHORE HAVE IMPROVED A TAD BUT MANY SITES ARE STILL UNDER ONE MILE. LAKE EFFECT ECHOES HAVE LOOKED GENERALLY WEAK TODAY WITH INVERSION HEIGHTS ONLY AROUND 4500 FT. BUFKIT PROFILES SHOW THE DGZ WHICH IS CURRENTLY NEAR THE GROUND LIFTING BACK UP INTO THE CLOUD LAYER TONIGHT AS SLIGHT WARMING TAKES PLACE. DECENT LIFT IS INDICATED IN THE DGZ AS WELL. THIS IMPLIES THAT LAKE EFFECT SNOW INTENSITY MAY INCREASE AGAIN THIS EVENING THROUGH EARLY WEDNESDAY... OR AT LEAST CHANGE FROM SMALL/FINE FLAKES TO FLUFFY DENDRITES THAT ACCUMULATE MORE EFFICIENTLY. THE LAKE EFFECT SNOW WILL GRADUALLY END ON WEDNESDAY AFTERNOON AND EVENING AS SFC HIGH PRESSURE MOVES IN. A LIMITING FACTOR FOR LAKE EFFECT IS THAT ICE COVERAGE ON LK MI IS INCREASING WHICH MEANS SHORTER FETCH LENGTHS AND PARCEL RESIDENCE TIMES. UNFORTUNATELY THE EXACT EXTENT OF THE ICE COVERAGE ON THE LAKE IS UNCLEAR AT THIS TIME DUE TO THE EXTENSIVE CLOUD COVER. WEB CAMS ALONG THE SHORE DO REVEAL CONSIDERABLE ICE HOWEVER. THE SET UP LOOKS GOOD FOR VERY COLD TEMPS ON WEDNESDAY NIGHT AS CLEARING SKIES AND LIGHT WINDS COUPLED WITH DEEP/FRESH SNOWPACK LEAD TO IDEAL RADIATIONAL COOLING. SOME LIGHT SNOW IS POSSIBLE LATE THURSDAY AND THURSDAY NIGHT RELATED TO WEAK ISENTROPIC LIFT. .LONG TERM...(FRIDAY THROUGH TUESDAY) ISSUED AT 329 PM EST TUE JAN 7 2014 TEMPERATURES ARE LOOKING WARMER THROUGH THE EXTENDED PERIOD AND WITH THOSE WARMER TEMPERATURES WILL COME SOME P-TYPE ISSUES. A HIGH AMPLITUDE TROUGH WILL FROM THE MIDDLE OF THE COUNTRY TOWARD THE GREAT LAKES FRIDAY. ISENTROPIC LIFT AHEAD OF THE TROUGH WILL RESULT IN PCPN DEVELOPMENT. LOW TEMPERATURES FRIDAY NIGHT ARE EXPECTED NEAR TO JUST BELOW FREEZING. FORECAST SOUNDINGS POINT TOWARD MORE RAIN THAN SNOW DEVELOPMENT. EVEN IF TEMPERATURES ARE JUST ABOVE FREEZING NEAR THE SURFACE...GROUND-LEVEL TEMPERATURES WILL LIKELY BE AT OR BELOW FREEZING. FREEZING RAIN SEEMS LIKE A REAL POSSIBILITY FRIDAY NIGHT. AFTER THE TROUGH PASSES THROUGH EARLY SATURDAY THE COLUMN COOLS ENOUGH THAT SNOW WILL PROBABLY BE THE MAIN P-TYPE. SFC TEMPS IN THE UPPER 30S WOULD ALSO LIKELY PRECLUDE FREEZING RAIN. ANOTHER TROUGH IS PROGD TO MOVE THROUGH SUNDAY NIGHT/MONDAY FOLLOWED BY ANOTHER MONDAY NIGHT/TUESDAY. EACH WILL BRING ANOTHER SHOT OF COOLER AIR...BUT NOT FRIGID LIKELY WE/VE SEEN RECENTLY. WE/LL BE LOOKING AT SNOW SHOWERS SUNDAY NIGHT THROUGH TUESDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1140 PM EST TUE JAN 7 2014 SNOW SHOWERS WILL CONTINUE TO BRING OF MVFR/IFR VSBY/CIGS TO MKG AND GRR THROUGH EARLY AFTERNOON BEFORE ENOUGH DRY AIR MOVES IN TO CLEAR THE SKIES. THE I-94 TAF SITES ARE ON THE EDGE OF THE CLOUDS...AZO HAS ONCE AGAIN GONE CLEAR...BTL WILL DO SO SHORTLY... AS WILL JXN. MVFR CIGS WILL MOVE INTO THE I-94 TAF ONCE AGAIN...BY 12-14Z. && .MARINE... ISSUED AT 329 PM EST TUE JAN 7 2014 WILL CANCEL THE GALE AND HEAVY FREEZING SPRAY WARNINGS WITH WINDS GRADUALLY SUBSIDING TONIGHT AND WEDNESDAY. && .HYDROLOGY... ISSUED AT 417 PM EST TUE JAN 7 2014 HYDRO CONCERNS ARE RELATIVELY MINIMAL IN THE SHORT TERM. RIVERS ARE LOCKED IN OR GRADUALLY FALLING IN THE VERY COLD AIR. THE FLOOD ADVISORY FOR THE FLAT RIVER AT SMYRNA WAS CANCELED MONDAY NIGHT. THE WHITE RIVER AT WHITEHALL WAS EXHIBITING A SHARP RISE UNTIL CRESTING THIS MORNING. IT HAS SINCE LEVELED OFF. RIVERS WILL CONTINUE GAINING ICE COVERAGE AND THICKNESS THROUGH THURSDAY. A WARM UP IS ON THE WAY FOR FRIDAY THROUGH EARLY NEXT WEEK. HIGHS ABOVE FREEZING IN THE 30S TO NEAR 40 ARE EXPECTED ALONG WITH A MIX OF RAIN AND SNOW FRIDAY AND SATURDAY. AT THIS POINT WE DO NOT ANTICIPATE ISSUES WITH ICE JAMMING AND FLOODING WITH THIS MINOR WARMUP. EVEN SO..RESIDENTS WHO LIVE ON RIVER BANKS SHOULD CONTINUE TO WATCH FOR ANY ICE MOVEMENT WHICH COULD LEAD TO ICE JAMS AND RISES IN RIVER LEVELS. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL 9 AM EST WEDNESDAY FOR MIZ037-043- 050-056-057-064-071. WIND CHILL ADVISORY UNTIL 9 AM EST WEDNESDAY FOR MIZ038>040- 044>046-051-052-058-059-065>067-072>074. LM...SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR LMZ844>849. && $$ UPDATE...NJJ SYNOPSIS...MEADE SHORT TERM...MEADE LONG TERM...93 AVIATION...WDM HYDROLOGY...HOVING/WALTON MARINE...MEADE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
602 PM CST THU JAN 9 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 313 PM CST THU JAN 9 2014 TONIGHT THROUGH FRIDAY NIGHT...EXITING HIGH PRES WILL MAINTAIN A SLY FLOW ACRS THE REGION OVERNIGHT THRU FRI NIGHT...RESULTING IN MUCH WARMER TEMPERATURES AND A MUCH MORE MOIST ATMOS. IN CONJUNCTION WITH THE SFC DEPICTION AIDING IN THE WARMING...A DIGGING LONGWAVE TROF OVER THE ROCKIES THIS EVE WILL SHIFT EWD INTO THE PLAINS DURG THE DAY ON FRI...THEN CONTINUE MOVG E OVER THE MISSISSIPPI RIVER FRI NIGHT. THIS TROF WILL AID IN THE DEVELOPMENT OF A LOW PRES CENTER OVER WRN KS. THE LOW WILL THEN BE LIFTED NE THRU IA AND WI ON ITS WAY INTO SE CANADA BY SAT MRNG. A PLUME OF DEEPER MOISTURE AHEAD OF THE TROF AND SFC LOW WILL BRING ADDITIONAL MOISTURE INTO THIS SYSTEM...ENOUGH SUCH THAT WINTRY PRECIP IS LIKELY OVER FAR SERN MN INTO W-CENTRAL WI. THERE IS SOME CONCERN THAT TEMP PROFILES IN THE BLYR WILL ALLOW FOR -ZR AT THE PRECIP ONSET...BUT HAVE KEPT PRECIP CHCS CAPPED IN THE MID-CHC RANGE FOR FRI MRNG DURG WHICH TIME -ZR IS POSSIBLE. AFTERWARDS...TEMPS WILL COOL DOWNWARD SUCH THAT PRECIP WILL EFFICIENTLY CHANGE OVER TO ALL -SN AND CHCS INCRS IN WRN WI FOR MINOR ACCUMULATING SNOW LATE DAY FRI THRU FRI NIGHT. UP TO 3 INCHES IS POSSIBLE...MAINLY IN EAU CLAIRE COUNTY...THEN AMOUNTS LESSEN GOING W AND N. WITH THE WARMER AIR...SNOW RATIOS WILL BE LOWER AND THE SNOWFALL WILL HAVE A HIGHER WATER CONTENT...WITH QPF IN THE 0.10-0.20 INCH AREA...MAINLY E OF INTERSTATE 35. AS FOR TEMPERATURES...THE MILDER AIR WILL REMAIN IN PLACE THRU FRI NIGHT. LOWS TONIGHT WILL DROP TO THE 10-20 DEGREE RANGE...COLDEST IN WI AND WARMEST IN SW MN. HIGHS ON FRI WILL RANGE FROM THE UPR 20S TO THE LWR 30S...AND THIS WILL BE FOLLOWED BY LOWS FRI NIGHT OF 15-25. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 313 PM CST THU JAN 9 2014 LIGHT SNOW WILL BE DEPARTING THE REGION AT THE START OF THE PERIOD AS A LOW PRESSURE SYSTEM DEVELOPS OVER THE GREAT LAKES REGION AND MOVES INTO ONTARIO/QUEBEC. THIS LOW IS DRIVEN BY AN AMPLIFYING LONGWAVE TROUGH THAT IS CURRENTLY CROSSING THE ROCKY MOUNTAINS. ANOTHER TROUGH WILL FOLLOW QUICKLY ON ITS HEELS FOR SUNDAY...WHICH WILL SPREAD ANOTHER WINTRY MIX ACROSS THE REGION. THE GFS AND ECMWF 0-3KM MAX T ARE SIMILAR IN THE SENSE THAT THEY HAVE MAX TEMPS AROUND 5C ACROSS THE REGION...WHILE THE SREF IS COOLER. THIS WOULD INDICATE THAT FREEZING RAIN IS POSSIBLE SUNDAY MORNING ACROSS MAINLY WESTERN MN WITH SURFACE TEMPS BELOW FREEZING...BUT IT SHOULD NOT LAST LONG AS TEMPS WARM ABOVE FREEZING BY MID DAY. ON MONDAY A CLIPPER SYSTEM WILL SPREAD SNOW ACROSS MAINLY NORTHERN MINNESOTA AND NORTHERN WISCONSIN. THIS WILL BE FOLLOWED BY COOLER TEMPERATURES TUESDAY. STILL YET ANOTHER STORM WILL TRACK ALONG THE INTERNATIONAL BORDER ON WEDNESDAY...AND COULD BRING SOME LIGHT PRECIP...AGAIN MAINLY NORTH...FOR THE MIDDLE OF NEXT WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 602 PM CST THU JAN 9 2014 STRATUS WITH CEILINGS LESS THAN 1K FEET ARE ADVANCING NORTHWARD ACROSS SE MN AND ADJOINING AREAS OF WI NEAR 10 KNOTS. THE CIGS HAVE ALREADY MOVED INTO KEAU AND COULD REACH KMSP AND KRNH IN THE 04Z TO 05Z TIME FRAME RESPECTIVELY. BELIEVE BOTH OF THESE TERMINALS WILL BE LOW MVFR/IFR AFTER 06Z. THE RAP 925MB RH IS DOING A MARVELOUS JOB AT CAPTURING THE EXPANDING LOW CEILINGS. IN FACT...IT WOULD HAVE KRWF...KAXN AND KSTC DROPPING TO LOW MVFR/IFR CIGS BY 09Z. LITTLE TO NO RECOVERY ON FRIDAY AS LOW LEVEL WARM/MOIST ADVECTION PREVAILS. BUFKIT TIME HEIGHT PROFILES SUPPORT SOME LIGHT FREEZING DRIZZLE IN THE LATE MORNING/EARLY AFTERNOON. THEREAFTER...ICE INTRODUCTION ALOFT WILL LEAD TO SOME LIGHT SNOW. MORE EXTENSIVE SNOW IS LIKELY AT KEAU FRIDAY EVENING...JUST BEYOND THE CURRENT TAF. SE WINDS 12-15 KNOTS TONIGHT AND FROM 8 TO 12 KNOTS ON FRIDAY. KMSP...CEILINGS BELOW 1K FEET FROM OWATONNA TO RED WING AT TAF ISSUANCE MAY REACH INTO THE AIRFIELD BY 04Z BASED ON CURRENT EXTRAPOLATION. THE TREND OVERNIGHT WILL BE FOR THE CEILINGS TO EXPAND NORTH AND WEST AS A WARM AND MOIST SOUTHERLY LOW LEVEL FLOW INCREASES. KEPT CEILINGS BELOW 1K FEET ON FRIDAY. THERE IS SOME THREAT FOR -FZDZ FRIDAY BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE IT IN THE TAF ATTM. DO BELIEVE THERE WILL BE SOME LIGHT SNOW FOR THE LATE AFTERNOON AND EVENING AS THE VERTICAL COLUMN SATURATES MORE DEEPLY WITH ICE. /OUTLOOK FOR KMSP/ SAT...VFR. WINDS W/WNW 10-15 KT. SUN...VFR. WINDS SW 10-15 KT. MON...VFR. WINDS W 5-10 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JPC LONG TERM...JRB AVIATION...RAH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
600 PM CST THU JAN 9 2014 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 306 PM CST THU JAN 9 2014 FOCUS IS ON POTENTIAL FOR LIGHT PRECIPITATION AS A SHORTWAVE TROUGH CROSSES THE CENTRAL PLAINS. WATER VAPOR IMAGERY INDICATED A PROGRESSIVE PATTERN IN THE WESTERLIES WITH A SHORTWAVE TROUGH DIGGING OVER THE ROCKIES EARLY THIS AFTERNOON. STRATUS AND SNOW COVER HAS IMPACTED TEMPERATURES TODAY...WITH THE STRATUS SLOW TO ERODE ACROSS OUR NORTHWEST ZONES...WHILE A NEW AREA OF STRATUS IS ADVECTING NORTHWARD THROUGH KS EARLY THIS AFTN. TEMPS HAVE MANAGED TO REACH THE MID 20S TO THE MID 30S SO FAR WITH A FEW MORE HOURS OF INSOLATION LEFT. FOR TONIGHT...SOUTHERLY LLVL FLOW INCREASES AHEAD OF THE TROUGH EMERGING ONTO THE HIGH PLAINS. STRATUS WILL CONTINUE TO ADVECT TO THE NORTH AND EAST AND SIMILAR TO THIS MORNING WE ARE LOOKING AT THE POTENTIAL FOR FOG DEVELOPMENT. WINDS LOOK TO REMAIN STEADY ENOUGH TO LIMIT DENSE FOG POTENTIAL BUT WILL NEED TO MONITOR AS THE RAP AND HRRR INDICATE SOME LOCATIONS COULD SEE DENSE FOG. AHEAD OF THE APPROACHING TROUGH...ISENTROPIC LIFT INCREASES AS INDICATED ON THE 295K SURFACE...PRIMARILY ORIENTED ACROSS OUR SOUTHEAST ZONES AND THE LIFT OVER THE LLVL MOISTURE COULD LEAD TO FREEZING DRIZZLE TOWARD MORNING AND THIS REMAINS IN THE FORECAST. ALSO ACROSS OUR WESTERN ZONES...HAVE INTRODUCED LOW POPS TOWARD DAYBREAK FRIDAY AS THE MID LEVEL TROUGH REACHES THIS AREA AND FORECAST SOUNDINGS FROM THE RAP INITIALLY INDICATE THE POTENTIAL FOR FREEZING DRIZZLE...THEN SATURATE TO MORE OF A IP/SN SOUNDING. HAVE MENTIONED ZL/IP FOR NOW WITH PCPN TYPE TRANSITIONING TO R/S DURING THE DAY FRIDAY. THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY ON HOW MUCH PCPN WILL BE AROUND DURING THE DAY ON FRIDAY WITH THE NAM REMAINING THE DRIEST AMONGST THE MODELS. THE SURFACE COLD FRONT SWEEPS EASTWARD FRIDAY MORNING...AND THE MID LEVEL TROUGH EXTENDS ACROSS OUR CENTRAL CWA AROUND MIDDAY BEFORE TRANSLATING EASTWARD DURING THE AFTERNOON. MID LEVEL MOISTURE INCREASES AS THE TROUGH MOVES IN AND A NARROW BAND OF MID LEVEL FRONTOGENESIS/LIFT MOVE ACROSS FM LATE MORNING INTO EARLY AFTERNOON...MORE ALIGNED ACROSS THE EASTERN HALF OF OUR CWA. HAVE INCREASED POPS DURING THIS TIME FRAME AS SPC WRF...GFS...ECMWF AND EVEN THE GEM INDICATE THE POTENTIAL FOR BANDED PCPN. FORECAST SOUNDINGS INDICATE THE POSSIBILITY OF A QUICK SHOT OF SNOW INITIALLY THEN DRY OUT/WARM BEHIND THE TROUGH AND HAVE MAINTAINED A SIMPLE RAIN/SNOW MIX FOR PCPN TYPE ATTM. WITH A WARMING TEMP PROFILE...GENERALLY DO NOT EXPECT MUCH IN THE WAY OF ACCUMULATION BUT WOULD NOT BE SURPRISED TO SEE MINOR AMOUNTS...GENERALLY UNDER ONE HALF OF AN INCH. THE TROUGH AXIS SHIFTS EASTWARD BY FRIDAY EVENING WITH CONDITIONS DRYING OUT/CLOUDS DECREASING IN SUBSIDENCE BEHIND THE DEPARTING SYSTEM. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 306 PM CST THU JAN 9 2014 OVERALL...THE LONG TERM PERIOD LOOKS TO BE MOSTLY DRY. BY FRIDAY NIGHT...THE MAIN TROUGH AXIS AND SURFACE LOW PRESSURE SYSTEM HAVE SHIFTED TO THE EAST OF THE PLAINS...WHILE AN UPPER LEVEL RIDGE AXIS SLOWLY BEGINS TO SHIFT ACROSS THE ROCKIES. WITH THIS RIDGE...AND A DEVELOPING LEE SURFACE TROUGH...SOUTHWEST WINDS WILL HELP BRING WARMER AIR TO THE PLAINS FOR SATURDAY. WENT A BIT ABOVE GUIDANCE FOR SATURDAY...WITH MOSTLY SUNNY SKIES AND SOUTHWEST WINDS...SEE NO REASON WHY WE CANNOT REACH THE UPPER 40S TO EVEN NEAR 50. BY SUNDAY...A WEAK UPPER LEVEL DISTURBANCE SHIFTS ACROSS THE PLAINS HELPING TO BREAK DOWN THE RIDGE. AS THE MAIN SURFACE LOW REMAINS WELL TO THE NORTH OF THE REGION...AN ASSOCIATED COLD FRONT WILL PASS THROUGH THE PLAINS SUNDAY. AT THIS POINT...WILL NOT REINTRODUCE POPS TO THE FORECAST AS THE SURFACE LOW REMAINS WELL TO THE NORTH. THAT BEING SAID...CANNOT RULE OUT A FEW SPRINKLES OR FLURRIES DURING THE DAY AND NIGHT ON SUNDAY. THE WAVE DEEPENS ACROSS THE PLAINS BY MONDAY...BRINGING COOLER 850 MB TEMPERATURES INTO THE OUTLOOK AREA. PERHAPS MONDAY MIGHT NEED TO BE A TAD COOLER THAN FORECAST BUT STILL CURRENTLY EXPECTING MID 40S FOR HIGHS. THROUGH THE REST OF THE LONG TERM...NUMEROUS WAVES CONTINUES TO DIVE SOUTH AND SKIRT ALONG THE PLAINS. HOWEVER...NONE OF THEM SUGGEST ANYTHING IN THE WAY OF PRECIPITATION OR A LONG LASTING COLD SPELL. IN FACT...RIDGING REBOUNDS ACROSS THE AREA BY WEDNESDAY BRINGING TEMPERATURES BACK UP TO NEAR 50. TOWARDS THURSDAY...YET ANOTHER UPPER LEVEL WAVE/CLOSED LOW WILL SHIFT THROUGH THE GREAT LAKES REGION DRAGGING A COLD FRONT ACROSS THE AREA. && .AVIATION...(FOR THE 00Z KGRI TAF THROUGH 00Z FRIDAY EVENING) ISSUED AT 555 PM CST THU JAN 9 2014 STRATUS WILL CONTINUE DO DESCEND OVERNIGHT WITH LOWERING VISIBILITY. MODELS ARE NOT INITIALIZING WELL...SO GOING WITH BEST GUESS. FOLLOWED MORE CLOSELY TO NAM MOS. FREEZING DRIZZLE SHOULD REMAIN SOUTH OF THE TERMINAL OVERNIGHT. COULD GET SOME RAIN/SNOW AS A TROUGH APPROACHES. WHEN THE WIND SWITCHES TO THE WEST/NORTHWEST BEHIND THE TROUGH...VISIBILITY AND CEILING WILL IMPROVE. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...FAY LONG TERM...SALTZMAN AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
652 AM CST WED JAN 8 2014 .UPDATE... ISSUED AT 651 AM CST WED JAN 8 2014 KLNX RADAR IN VCP31 IS GROWING VERY QUIET WITH ECHO RETURNS RAPIDLY DECREASING. IT APPEARS OUR WEAK UA DISTURBANCE IS EXITING THE FORECAST AREA. A NEW FORECAST IS OUT FOR FLURRIES ENDING THIS MORNING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CST WED JAN 8 2014 ARCTIC HIGH PRESSURE...ANGLED NORTHWEST TO SOUTHEAST ACROSS NORTH DAKOTA WILL DRIFT SOUTHEAST INTO SRN WISCONSIN BY THURSDAY MORNING. SFC LOW PRESSURE WILL BUILD ACROSS THE CANADIAN ROCKIES AND INTO WRN ALBERTA BY THIS TIME SETTING UP A SOUTH AND SOUTHWEST LOW LEVEL WIND FIELD ACROSS THE FCST AREA. MOISTURE IS EXPECTED TO REMAIN TRAPPED UNDER THE WRN PERIPHERY OF THE ARCTIC RIDGE MAINTAINING EXTENSIVE CLOUDINESS TODAY AND TONIGHT. IT LOOKS LIKE THE NORTHWEST ZONES COULD SEE SOME CLEARING BY THURSDAY MORNING WHILE THE REST OF THE FCST AREA REMAINS OVERCAST. THE LOW CLOUDS APPEAR TO BE OVERDONE IN THE NAM...GFS AND RAP MODELS BUT GIVEN THE UPSLOPE EAST AND SOUTHEAST WINDS DEVELOPING OR FORECAST TO DEVELOP...THESE MODELS MAY BE TOO FAST. OVERALL THE FORECAST CALLS FOR THE CLOUDS TO REMAIN LOCKED IN TODAY AND TONIGHT. THE LIGHT SNOW FORECAST APPEARS TO BE ON TRACK WITH NO SFC OBS REPORTING LESS THAN 1 MILE VISIBILITY OVERNIGHT AND RADAR SUGGESTS THE AREA OF SNOW IS MOVING OFF TO THE EAST. THE FORECAST CONTINUES LIGHT SNOW THIS MORNING WITH FLURRIES THROUGH EARLY AFTERNOON. NOTE THAT SEVERAL MODELS FORECAST 2 INCH SNOW TOTALS IN PLACES BUT A LOOK AT THE NEDOR CAMS INDICATES LESS THAN AN INCH ACCUMULATIONS AT ALL LOCATIONS VISIBLE AND NONE OF THE CAMS SUGGESTED MODERATE SNOW WAS FALLING. HIGH TEMPERATURES TODAY SHOULD RISE INTO THE UPPER TEENS NEAR HIGHWAY 281 WITH WARMER READINGS RISING TO THE LOWER 30S WESTWARD ACROSS SOUTHWESTERN NEB AND THE ERN PANHANDLE. LOWS TONIGHT FALL INTO TEENS. A 30 TO 40 KT LOW LEVEL JET WILL BE DEVELOPING TONIGHT AND THIS IN COMBINATION WITH THE CLOUD COVER SHOULD KEEP LOWS ON THE WARM SIDE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 343 AM CST WED JAN 8 2014 ROLLER COAST OF TEMPS CONTINUE WITH HIGHS GOING UP FOR THURSDAY AS WAA AHEAD OF THE NEXT APPROACHING WEAK TROUGH. MOSTLY SUNNY SKIES AND HIGHS IN THE MID 30S EAST TO LOWER 40S SW. WILL NEED TO MONITOR EXISTING SNOW AS AN INCH OR SO MAY CAUSE TEMPS TO BE LOWER THAN CURRENT FORECAST BY A FEW DEGREES...HOWEVER SW WINDS IN THE 15 TO 25 MPH RANGE WHICH WILL HELP IN MIXING THE LOWER LEVELS. UPPER LEVEL TROUGH TO MOVE ACROSS THE HIGH PLAINS ON FRIDAY. SFC LOW TRACKS FROM NW TX TO THE NE...WHICH IS IN GOOD AGREEMENT WITH THE MODELS. LIFT/PRECIP DOES SEE MINOR PATH ADJUSTMENTS...HOWEVER MODELS ALL KEEP IT TO THE SE OF THE CWA. AS WINDS BECOME NW DURING THE DAY...A BRIEF MIXING WILL STILL HELP TO WARM TEMPS TO SEASONAL NORMS...POSSIBLY EVEN WARMER. UPPER LEVEL TROUGH WILL PUSH EAST BY SATURDAY WITH STRONG WAA. TEMPS FRIDAY NIGHT COULD BE EARLY...PENDING SOME MINOR TIMING ADJUSTMENTS TO ARRIVAL OF WARMER AIR. EITHER WAY...WARMER FOR SATURDAY WITH 40S FOR MOST AREAS...AND EVEN 50 FOR SW. BY SATURDAY NIGHT THE NEXT SHORT WAVE WILL BE PUSHING ACROSS THE ROCKIES. INCREASING CLOUDS SHOULD HOLD TEMPS WELL ABOVE NORMAL...WITH MID 20S TO AROUND 30 EXPECTED SUNDAY MORN. AS THE WAVE MOVES ACROSS SUNDAY MODELS HAVE FAIRLY STRONG WINDS ALOFT...WITH 850 MB WINDS NEAR 50 KTS. MODELS DO NOT MIX ALL THIS DOWN...HOWEVER DO EXPECT A WINDY DAY AND WILL MONITOR FOR POTENTIAL ADVISORY CONDITIONS. ANOTHER ISSUE WILL BE SOME WEAK LIFT WITH THE WAVE. MOISTURE IS LIMITED INITIALLY AND WILL BE A TOP DOWN SATURATION. ANOTHER ISSUE IS TEMPS WITH THIS WAVE. STILL SEEING SOME WARM AIR AT THE SURFACE WITH GUIDANCE IN AGREEMENT WITH HIGHS WARMING INTO THE 40S. LONG RANGE SOUNDINGS WOULD SUGGEST SNOW EARLY IN THE DAY...WITH WARMING TEMPS AND A CHANGE OVER TO RAIN. FOR NEXT WEEK...RIDGE AMPLIFIES OUT WEST...ALTHOUGH SOME MODELS DISAGREEMENT WITH THE STRENGTH. GFS IS WEAKER WITH THE RIDGE AND ALLOWS ANOTHER CLIPPER TO BACK ACROSS THE HIGH PLAINS ON TUESDAY...WHILE THE EC IS A LITTLE STRONG WITH THE RIDGE AND KEEPS THE CLIPPER TO THE NORTHEAST. PENDING HOW FAR TO THE SW THE CLIPPER DOES PUSHES...WILL PLAY A BIG PART TO THE FORECAST. THUS FOR EARLY NEXT WEEK FORECAST HAS LOW CONFIDENCE. THOUGHT IS FOR THE WARMER/DRIER AIR TO WIN...AS MOST OF THE WINTER THE BULK OF THE WAVES HAVE GONE EAST OF THE AREA. THAT SAID...COOLER AIR AND POSSIBLY SOME LIGHT PRECIP /FLURRIES OR SPRINKLES/ CAN NOT BE RULED OUT FOR EARLY NEXT WEEK AND WILL NEED TO BE WATCHED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 527 AM CST WED JAN 8 2014 THE AREA OF MVFR/IFR CIGS AND VSBY IN LIGHT SNOW ACROSS NORTH CENTRAL NEBRASKA IS EXPECTED TO TRANSITION TO MVFR CIGS BY 18Z. GIVEN THE UPSLOPE WINDS DEVELOPING THIS MORNING...MOISTURE SHOULD BECOME TRAPPED ACROSS THE FCST AREA THIS AFTERNOON THROUGH TONIGHT. MEANWHILE...LOW LEVEL WINDS WILL INCREASE TONIGHT WHICH SUGGESTS THERE IS A GOOD POTENTIAL FOR THE REDEVELOPMENT OF IFR CIGS. SOME IMPROVEMENT IS EXPECTED LATE TONIGHT AS THE LOW LEVEL JET VEERS OFF WHICH COULD PRODUCE VFR AFTER 06Z FROM WEST TO EAST ACROSS WESTERN NEBRASKA. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...CDC SHORT TERM...CDC LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
525 AM CST WED JAN 8 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CST WED JAN 8 2014 MAIN FORECAST CONCERNS WILL BE SNOW CHANCES TODAY AND FREEZING DRIZZLE CHANCES LATE TONIGHT...AS WELL AS TEMPERATURES. RADAR AND OBSERVATIONS HAVE SOME LIGHT SNOW THAT HAS DEVELOPED MAINLY NORTH OF INTERSTATE 80 EARLY THIS MORNING. SO FAR OBSERVATIONS HAVE NOT HAD VERY LOW VISIBILITIES WITH THE SNOW. A COUPLE OF UPPER LEVEL WAVES WILL BE MOVING THROUGH THE REGION TODAY AND TONIGHT. THE SNOW THAT HAS DEVELOPED ACROSS THE NORTHERN PORTION OF THE AREA IS EXPECTED TO SPREAD TO THE SOUTH EARLY THIS MORNING. THE NAM AND GFS ARE SIMILAR IN DEVELOPING A BAND OF SNOW ACROSS THE NORTH THEN MOVING IT TOWARD THE SOUTHEAST THIS MORNING AND THE PRECIPITATION SHOULD BE EXITING THE AREA DURING THE AFTERNOON. THE ONLY CONCERN IS THE HRRR AND 4KM WRF BOTH ARE MUCH WEAKER WITH PRECIPITATION. THE HRRR DOES NOT GO OUT VERY FAR INTO THE MORNING HOURS AT THIS TIME. WILL CONTINUE WITH THE SNOW WITH THE BEST CHANCES FOR SNOW WILL BE DURING THE MORNING HOURS AND MAINLY TO THE NORTH AND EAST OF THE TRI-CITIES. SNOWFALL AMOUNTS SHOULD BE A HALF INCH TO AROUND AN INCH ACROSS NEBRASKA AND LESS THAN A HALF INCH IN NORTH CENTRAL KANSAS. THE SNOW SHOULD COME TO AN END FROM WEST TO EAST LATE THIS AFTERNOON. THE MAIN CONCERN FOR TONIGHT WILL BE LATE TONIGHT. AFTER THE SNOW MOVES OUT THE MID LEVELS DRY OUT SOME AND THE DENDRITIC LAYER IS DRY..BUT LATE TONIGHT THERE IS A SHALLOW MOIST LAYER THAT IS COLD. THIS COULD BRING A CHANCE FOR SOME LIGHT FREEZING DRIZZLE. THE PREVIOUS FORECAST HAD JUST THE FAR SOUTHEAST. FORECAST SOUNDINGS INDICATE THE BEST CHANCE WILL CONTINUE TO BE IN THE FAR SOUTHEAST. A LITTLE FURTHER TO THE NORTHWEST THERE IS A SHALLOW LAYER OF MOISTURE BUT IT IS FAIRLY SHORT LIVED BEFORE IT STARTS TO DRY OUT. WILL HAVE TO WATCH TO SEE IF THAT MOIST LAYER CONTINUES OR WHETHER IT WILL DRY OUT. CURRENT TEMPERATURES ARE IN THE 20S ACROSS THE FORECAST AREA...WHICH IS VERY NEAR TO THE FORECAST HIGHS FOR TOMORROW. STILL EXPECT THE TEMPERATURES TO DROP OFF TOWARD MORNING SO WILL LEAVE FORECAST HIGHS AS THEY ARE FOR NOW. LOWS TONIGHT WILL DIP DOWN TO A FEW DEGREES EITHER SIDE OF 10 DEGREES. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 345 AM CST WED JAN 8 2014 GUIDANCE SUGGESTS QUASI-ZONAL FLOW WILL BE NOTED ACROSS MUCH OF THE CONUS TO START THE LONG TERM FORECAST PERIOD ON THURSDAY...ALTHOUGH A MID LEVEL SHORTWAVE WILL ALSO BE MOVING INTO THE NORTHWESTERN CONUS BY 12Z THURSDAY. GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SUGGEST THIS MID LEVEL SHORTWAVE WILL MOVE SOUTHEAST INTO THE FOUR CORNERS REGION BY 12Z FRIDAY...INTO CENTRAL TEXAS BY 00Z SATURDAY...AND NEAR THE LOWER MISSISSIPPI VALLEY BY 12Z SATURDAY. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE IS EXPECTED TO BE REALIZED OVER THE PANHANDLE OF TEXAS BY 12Z FRIDAY. THIS SURFACE LOW IS THEN EXPECTED TO QUICKLY MOVE NORTHEAST AND NEAR THE GREAT LAKES REGION BY 12Z SATURDAY. MID LEVEL THERMAL ADVECTION AND INCREASING TROPOSPHERIC MOISTURE SHOULD PROMOTE PRECIPITATION PRODUCTION ACROSS MUCH OF THE SOUTHERN PLAINS THURSDAY NIGHT...WITH THE PRIMARY AXIS OF MID LEVEL OMEGA THEN EXPECTED TO MOVE INTO POTIONS OF THE MID TO LOWER MISSISSIPPI VALLEY DURING THE DAY FRIDAY...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN. ALL THAT BEING SAID...MODEL GUIDANCE CONTINUES TO SUGGEST THE WEST/NORTHWESTERN PERIPHERY OF THIS OMEGA AXIS WILL CLIP PORTIONS OF THE CENTRAL PLAINS DURING THE DAY FRIDAY...WITH THE SOUTHEASTERN HALF OUR CWA STILL EXPECTED TO OBSERVE MEASURABLE PRECIPITATION DURING THE DAY FRIDAY. GIVEN THE MODEL AGREEMENT...AS WELL AS MODEL CONSISTENCY THROUGH THE PAST 24 HOURS...OPTED TO KEEP POPS GOING ACROSS ROUGHLY THE SOUTHEASTERN HALF OF THE CWA 12Z FRIDAY THROUGH 00Z SATURDAY...AND ACTUALLY INCREASED POPS ACROSS THE SOUTHEASTERN ONE-THIRD OF THE CWA INTO THE 40-50% RANGE. GUIDANCE ALSO SUGGESTS SURFACE TEMPERATURES ACROSS OUR CWA ON FRIDAY WILL START IN THE LOWER 20S...BUT EVENTUALLY RISE RISE INTO THE 30S TO NEAR 40 FRIDAY AFTERNOON. FORECAST PROXIMITY SOUNDINGS FROM THE ACROSS OUR CWA...PER THE NAM AND OPERATIONAL GFS...CONTINUE TO SUGGEST A SIGNIFICANT WARM LAYER WILL EXIST...PRIMARILY BETWEEN 750MB AND 900MB...THROUGH 15Z OR 18Z FRIDAY. AS A RESULT...FREEZING RAIN CONTINUES TO LOOK LIKE A POSSIBILITY GENERALLY ALONG AND SOUTHEAST OF LINE FROM PHILLIPSBURG...TO GRAND ISLAND AND FULLERTON...WITH CHANCES FOR SUCH ACTIVITY INCREASING AS ONE MOVES SOUTHEAST ACROSS THE CWA. THESE SAME FORECAST PROXIMITY SOUNDINGS ALSO SUGGEST WE WILL LIKELY BE WAITING FOR THE MID TO LOWER TROPOSPHERE TO SATURATE UNTIL AROUND 12Z FRIDAY...THUS IS WHY THE AFOREMENTIONED POPS WERE NOT INTRODUCED UNTIL 12Z FRIDAY. IN ADDITION...BASED ON GUIDANCE...IT APPEARS THE TEMPERATURE THROUGH MOST LOCATIONS ACROSS THE CWA WILL RISE ABOVE FREEZING BY 18Z AND AS A RESULT...FREEZING RAIN WORDING COMES TO AN END IN THE OFFICIAL FORECAST BY 18Z FRIDAY...WITH RAIN THEN EXPECTED WITH ANY PRECIPITATION THROUGH THE REST OF THE DAY. TAKING AN AVERAGE OF THE NAM...OPERATIONAL GFS...EC...SREF-MEAN AND WPC GUIDANCE PROVIDES LIQUID PRECIPITATION AMOUNTS OF A COUPLE HUNDREDTHS OF AN INCH NEAR THE TRI-CITIES...TO AROUND 0.10" FARTHER SOUTHEAST DURING THE 12-18Z FRIDAY TIMEFRAME. ADDITIONAL LIQUID PRECIPITATION AMOUNTS OF 0.01-0.05" ARE THEN ANTICIPATED ACROSS OUR EAST/SOUTHEAST FRIDAY AFTERNOON. GIVEN ALL THIS IT CERTAINLY SEEMS AS THOUGH WE ARE HEADING TOWARDS AN ADVISORY- WORTHY EVENT ON FRIDAY WITH A FEW HUNDREDTHS TO PERHAPS A TENTH OF AN INCH OF ICING APPEARING POSSIBLE ACROSS THE SOUTHEASTERN HALF OF THE CWA. AS MENTIONED YESTERDAY...WE ARE STILL ABOUT 24 HOURS FROM THIS MID LEVEL SHORTWAVE ACTUALLY MAKING LANDFALL OVER THE NORTHWESTERN CONUS...AT WHICH TIME SUFFICIENT SAMPLING BY THE UPPER AIR NETWORK SHOULD ALLOW MODEL GUIDANCE TO REALLY NAIL DOWN THE TRACK AND TIMING OF THIS SYSTEM. PROVIDED THE CONTINUED UNCERTAINTY OF THIS SYSTEM...WILL CONTINUE TO KEEP THE HWO SOMEWHAT VAGUE WITH RESPECT TO ICING AMOUNTS...BUT CERTAINLY MAINTAIN THE MENTION OF FREEZING RAIN FRIDAY MORNING WITH THE POTENTIAL FOR DIFFICULT DRIVING CONDITIONS. AS ALREADY MENTIONED...IT APPEARS WE WILL BE WAITING FOR THE MID TO LOWER TROPOSPHERE TO SATURATE THROUGH ABOUT 12Z FRIDAY. THAT BEING SAID...PERSISTENT SOUTHERLY LOW LEVEL FLOW AND RESULTANT LOW LEVEL MOISTURE FLUX INTO THE AREA SHOULD ALLOW FOR RISING DEW POINT VALUES ACROSS MUCH OF OUR CWA THURSDAY NIGHT INTO FRIDAY MORNING. GUIDANCE FROM THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST 0-0.5KM RH VALUES WILL CLIMB INTO THE 90-100% RANGE ACROSS ROUGHLY THE SOUTHEASTERN ONE-THIRD OF OUR CWA BETWEEN 06Z AND 12Z FRIDAY. THESE SAME SETS OF GUIDANCE ALSO SUGGEST LOW LEVEL TURBULENT MIXING ON THE ORDER OF 15-20KTS WILL BE PRESENT DURING THE SAME TIME PERIOD. GIVEN ALL THIS...WILL CONTINUE THE MENTION OF FREEZING DRIZZLE...ROUGHLY ALONG AND SOUTHEAST OF A LINE FROM PHILLIPSBURG TO HEBRON....IN THE HWO AND GRIDS 06-12Z FRIDAY. BEYOND THE DAY FRIDAY...THE MAJORITY OF THE LONG TERM FORECAST PERIOD REMAINS DRY...WITH THE ONLY EXCEPTION BEING SUNDAY INTO SUNDAY NIGHT. BOTH THE OPERATIONAL GFS AND EC SUGGEST A MID LEVEL SHORTWAVE WILL MOVE ACROSS THE REGION DURING THIS TIME PERIOD AND ALLBLEND RESPONDED BY PROVIDING ~20% POPS TO MUCH OF THE CWA. THESE POPS WERE LEFT UNCHANGED FOR THE MOST PART. A WARM LOW LEVEL AIRMASS IS EXPECTED TO MAINTAIN ITSELF ACROSS THE CENTRAL PLAINS THROUGHOUT THE LONG TERM FORECAST PERIOD...WITH AFTERNOON HIGHS IN THE 30S TO NEAR 40 THURSDAY AND FRIDAY...AND IN THE 40S TO NEAR 50 SATURDAY ONWARD. OVERNIGHT LOWS IN THE TEENS AND 20S WILL ALSO LIKELY BE COMMON DURING THE LONG TERM FORECAST PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 525 AM CST WED JAN 8 2014 SNOW CONTINUES TO MOVE THROUGH THE KGRI TERMINAL AREA EARLY THIS MORNING. THE HEAVIEST SNOW THAT WILL REDUCE VISIBILITIES AND CEILINGS THE MOST WILL BE FOR A FEW HOURS THIS MORNING. STILL EXPECT MVFR CONDITIONS THROUGH THE REMAINDER OF THE PERIOD. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...BRYANT AVIATION...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
345 AM CST WED JAN 8 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 345 AM CST WED JAN 8 2014 MAIN FORECAST CONCERNS WILL BE SNOW CHANCES TODAY AND FREEZING DRIZZLE CHANCES LATE TONIGHT...AS WELL AS TEMPERATURES. RADAR AND OBSERVATIONS HAVE SOME LIGHT SNOW THAT HAS DEVELOPED MAINLY NORTH OF INTERSTATE 80 EARLY THIS MORNING. SO FAR OBSERVATIONS HAVE NOT HAD VERY LOW VISIBILITIES WITH THE SNOW. A COUPLE OF UPPER LEVEL WAVES WILL BE MOVING THROUGH THE REGION TODAY AND TONIGHT. THE SNOW THAT HAS DEVELOPED ACROSS THE NORTHERN PORTION OF THE AREA IS EXPECTED TO SPREAD TO THE SOUTH EARLY THIS MORNING. THE NAM AND GFS ARE SIMILAR IN DEVELOPING A BAND OF SNOW ACROSS THE NORTH THEN MOVING IT TOWARD THE SOUTHEAST THIS MORNING AND THE PRECIPITATION SHOULD BE EXITING THE AREA DURING THE AFTERNOON. THE ONLY CONCERN IS THE HRRR AND 4KM WRF BOTH ARE MUCH WEAKER WITH PRECIPITATION. THE HRRR DOES NOT GO OUT VERY FAR INTO THE MORNING HOURS AT THIS TIME. WILL CONTINUE WITH THE SNOW WITH THE BEST CHANCES FOR SNOW WILL BE DURING THE MORNING HOURS AND MAINLY TO THE NORTH AND EAST OF THE TRI-CITIES. SNOWFALL AMOUNTS SHOULD BE A HALF INCH TO AROUND AN INCH ACROSS NEBRASKA AND LESS THAN A HALF INCH IN NORTH CENTRAL KANSAS. THE SNOW SHOULD COME TO AN END FROM WEST TO EAST LATE THIS AFTERNOON. THE MAIN CONCERN FOR TONIGHT WILL BE LATE TONIGHT. AFTER THE SNOW MOVES OUT THE MID LEVELS DRY OUT SOME AND THE DENDRITIC LAYER IS DRY..BUT LATE TONIGHT THERE IS A SHALLOW MOIST LAYER THAT IS COLD. THIS COULD BRING A CHANCE FOR SOME LIGHT FREEZING DRIZZLE. THE PREVIOUS FORECAST HAD JUST THE FAR SOUTHEAST. FORECAST SOUNDINGS INDICATE THE BEST CHANCE WILL CONTINUE TO BE IN THE FAR SOUTHEAST. A LITTLE FURTHER TO THE NORTHWEST THERE IS A SHALLOW LAYER OF MOISTURE BUT IT IS FAIRLY SHORT LIVED BEFORE IT STARTS TO DRY OUT. WILL HAVE TO WATCH TO SEE IF THAT MOIST LAYER CONTINUES OR WHETHER IT WILL DRY OUT. CURRENT TEMPERATURES ARE IN THE 20S ACROSS THE FORECAST AREA...WHICH IS VERY NEAR TO THE FORECAST HIGHS FOR TOMORROW. STILL EXPECT THE TEMPERATURES TO DROP OFF TOWARD MORNING SO WILL LEAVE FORECAST HIGHS AS THEY ARE FOR NOW. LOWS TONIGHT WILL DIP DOWN TO A FEW DEGREES EITHER SIDE OF 10 DEGREES. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 345 AM CST WED JAN 8 2014 GUIDANCE SUGGESTS QUASI-ZONAL FLOW WILL BE NOTED ACROSS MUCH OF THE CONUS TO START THE LONG TERM FORECAST PERIOD ON THURSDAY...ALTHOUGH A MID LEVEL SHORTWAVE WILL ALSO BE MOVING INTO THE NORTHWESTERN CONUS BY 12Z THURSDAY. GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL SUGGEST THIS MID LEVEL SHORTWAVE WILL MOVE SOUTHEAST INTO THE FOUR CORNERS REGION BY 12Z FRIDAY...INTO CENTRAL TEXAS BY 00Z SATURDAY...AND NEAR THE LOWER MISSISSIPPI VALLEY BY 12Z SATURDAY. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE IS EXPECTED TO BE REALIZED OVER THE PANHANDLE OF TEXAS BY 12Z FRIDAY. THIS SURFACE LOW IS THEN EXPECTED TO QUICKLY MOVE NORTHEAST AND NEAR THE GREAT LAKES REGION BY 12Z SATURDAY. MID LEVEL THERMAL ADVECTION AND INCREASING TROPOSPHERIC MOISTURE SHOULD PROMOTE PRECIPITATION PRODUCTION ACROSS MUCH OF THE SOUTHERN PLAINS THURSDAY NIGHT...WITH THE PRIMARY AXIS OF MID LEVEL OMEGA THEN EXPECTED TO MOVE INTO POTIONS OF THE MID TO LOWER MISSISSIPPI VALLEY DURING THE DAY FRIDAY...A SOLUTION SUPPORTED BY QPF FIELDS FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN. ALL THAT BEING SAID...MODEL GUIDANCE CONTINUES TO SUGGEST THE WEST/NORTHWESTERN PERIPHERY OF THIS OMEGA AXIS WILL CLIP PORTIONS OF THE CENTRAL PLAINS DURING THE DAY FRIDAY...WITH THE SOUTHEASTERN HALF OUR CWA STILL EXPECTED TO OBSERVE MEASURABLE PRECIPITATION DURING THE DAY FRIDAY. GIVEN THE MODEL AGREEMENT...AS WELL AS MODEL CONSISTENCY THROUGH THE PAST 24 HOURS...OPTED TO KEEP POPS GOING ACROSS ROUGHLY THE SOUTHEASTERN HALF OF THE CWA 12Z FRIDAY THROUGH 00Z SATURDAY...AND ACTUALLY INCREASED POPS ACROSS THE SOUTHEASTERN ONE-THIRD OF THE CWA INTO THE 40-50% RANGE. GUIDANCE ALSO SUGGESTS SURFACE TEMPERATURES ACROSS OUR CWA ON FRIDAY WILL START IN THE LOWER 20S...BUT EVENTUALLY RISE RISE INTO THE 30S TO NEAR 40 FRIDAY AFTERNOON. FORECAST PROXIMITY SOUNDINGS FROM THE ACROSS OUR CWA...PER THE NAM AND OPERATIONAL GFS...CONTINUE TO SUGGEST A SIGNIFICANT WARM LAYER WILL EXIST...PRIMARILY BETWEEN 750MB AND 900MB...THROUGH 15Z OR 18Z FRIDAY. AS A RESULT...FREEZING RAIN CONTINUES TO LOOK LIKE A POSSIBILITY GENERALLY ALONG AND SOUTHEAST OF LINE FROM PHILLIPSBURG...TO GRAND ISLAND AND FULLERTON...WITH CHANCES FOR SUCH ACTIVITY INCREASING AS ONE MOVES SOUTHEAST ACROSS THE CWA. THESE SAME FORECAST PROXIMITY SOUNDINGS ALSO SUGGEST WE WILL LIKELY BE WAITING FOR THE MID TO LOWER TROPOSPHERE TO SATURATE UNTIL AROUND 12Z FRIDAY...THUS IS WHY THE AFOREMENTIONED POPS WERE NOT INTRODUCED UNTIL 12Z FRIDAY. IN ADDITION...BASED ON GUIDANCE...IT APPEARS THE TEMPERATURE THROUGH MOST LOCATIONS ACROSS THE CWA WILL RISE ABOVE FREEZING BY 18Z AND AS A RESULT...FREEZING RAIN WORDING COMES TO AN END IN THE OFFICIAL FORECAST BY 18Z FRIDAY...WITH RAIN THEN EXPECTED WITH ANY PRECIPITATION THROUGH THE REST OF THE DAY. TAKING AN AVERAGE OF THE NAM...OPERATIONAL GFS...EC...SREF-MEAN AND WPC GUIDANCE PROVIDES LIQUID PRECIPITATION AMOUNTS OF A COUPLE HUNDREDTHS OF AN INCH NEAR THE TRI-CITIES...TO AROUND 0.10" FARTHER SOUTHEAST DURING THE 12-18Z FRIDAY TIMEFRAME. ADDITIONAL LIQUID PRECIPITATION AMOUNTS OF 0.01-0.05" ARE THEN ANTICIPATED ACROSS OUR EAST/SOUTHEAST FRIDAY AFTERNOON. GIVEN ALL THIS IT CERTAINLY SEEMS AS THOUGH WE ARE HEADING TOWARDS AN ADVISORY- WORTHY EVENT ON FRIDAY WITH A FEW HUNDREDTHS TO PERHAPS A TENTH OF AN INCH OF ICING APPEARING POSSIBLE ACROSS THE SOUTHEASTERN HALF OF THE CWA. AS MENTIONED YESTERDAY...WE ARE STILL ABOUT 24 HOURS FROM THIS MID LEVEL SHORTWAVE ACTUALLY MAKING LANDFALL OVER THE NORTHWESTERN CONUS...AT WHICH TIME SUFFICIENT SAMPLING BY THE UPPER AIR NETWORK SHOULD ALLOW MODEL GUIDANCE TO REALLY NAIL DOWN THE TRACK AND TIMING OF THIS SYSTEM. PROVIDED THE CONTINUED UNCERTAINTY OF THIS SYSTEM...WILL CONTINUE TO KEEP THE HWO SOMEWHAT VAGUE WITH RESPECT TO ICING AMOUNTS...BUT CERTAINLY MAINTAIN THE MENTION OF FREEZING RAIN FRIDAY MORNING WITH THE POTENTIAL FOR DIFFICULT DRIVING CONDITIONS. AS ALREADY MENTIONED...IT APPEARS WE WILL BE WAITING FOR THE MID TO LOWER TROPOSPHERE TO SATURATE THROUGH ABOUT 12Z FRIDAY. THAT BEING SAID...PERSISTENT SOUTHERLY LOW LEVEL FLOW AND RESULTANT LOW LEVEL MOISTURE FLUX INTO THE AREA SHOULD ALLOW FOR RISING DEW POINT VALUES ACROSS MUCH OF OUR CWA THURSDAY NIGHT INTO FRIDAY MORNING. GUIDANCE FROM THE NAM...OPERATIONAL GFS AND EC ALL SUGGEST 0-0.5KM RH VALUES WILL CLIMB INTO THE 90-100% RANGE ACROSS ROUGHLY THE SOUTHEASTERN ONE-THIRD OF OUR CWA BETWEEN 06Z AND 12Z FRIDAY. THESE SAME SETS OF GUIDANCE ALSO SUGGEST LOW LEVEL TURBULENT MIXING ON THE ORDER OF 15-20KTS WILL BE PRESENT DURING THE SAME TIME PERIOD. GIVEN ALL THIS...WILL CONTINUE THE MENTION OF FREEZING DRIZZLE...ROUGHLY ALONG AND SOUTHEAST OF A LINE FROM PHILLIPSBURG TO HEBRON....IN THE HWO AND GRIDS 06-12Z FRIDAY. BEYOND THE DAY FRIDAY...THE MAJORITY OF THE LONG TERM FORECAST PERIOD REMAINS DRY...WITH THE ONLY EXCEPTION BEING SUNDAY INTO SUNDAY NIGHT. BOTH THE OPERATIONAL GFS AND EC SUGGEST A MID LEVEL SHORTWAVE WILL MOVE ACROSS THE REGION DURING THIS TIME PERIOD AND ALLBLEND RESPONDED BY PROVIDING ~20% POPS TO MUCH OF THE CWA. THESE POPS WERE LEFT UNCHANGED FOR THE MOST PART. A WARM LOW LEVEL AIRMASS IS EXPECTED TO MAINTAIN ITSELF ACROSS THE CENTRAL PLAINS THROUGHOUT THE LONG TERM FORECAST PERIOD...WITH AFTERNOON HIGHS IN THE 30S TO NEAR 40 THURSDAY AND FRIDAY...AND IN THE 40S TO NEAR 50 SATURDAY ONWARD. OVERNIGHT LOWS IN THE TEENS AND 20S WILL ALSO LIKELY BE COMMON DURING THE LONG TERM FORECAST PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1124 PM CST TUE JAN 7 2014 ALREADY SEEING SOME RETURNS ON RADAR TO THE NORTH OF THE KGRI TERMINAL AND AS THE NIGHT PROGRESSES THE SNOW SHOULD MOVE TO THE SOUTH AND INTO THE KGRI TERMINAL. BROUGHT IT IN A LITTLE EARLIER THAN BEFORE AND HAVE SOME CONCERN THAT IT MIGHT BE EARLIER YET. THE BEST CHANCE FOR SNOW AND LOWER CEILINGS AND VISIBILITIES WILL BE DURING THE MORNING HOURS. SNOW SHOULD END BY LATER THIS AFTERNOON BUT CEILINGS WILL REMAIN MVFR THROUGH THE PERIOD. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...BRYANT AVIATION...JCB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
343 AM CST WED JAN 8 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 343 AM CST WED JAN 8 2014 ARCTIC HIGH PRESSURE...ANGLED NORTHWEST TO SOUTHEAST ACROSS NORTH DAKOTA WILL DRIFT SOUTHEAST INTO SRN WISCONSIN BY THURSDAY MORNING. SFC LOW PRESSURE WILL BUILD ACROSS THE CANADIAN ROCKIES AND INTO WRN ALBERTA BY THIS TIME SETTING UP A SOUTH AND SOUTHWEST LOW LEVEL WIND FIELD ACROSS THE FCST AREA. MOISTURE IS EXPECTED TO REMAIN TRAPPED UNDER THE WRN PERIPHERY OF THE ARCTIC RIDGE MAINTAINING EXTENSIVE CLOUDINESS TODAY AND TONIGHT. IT LOOKS LIKE THE NORTHWEST ZONES COULD SEE SOME CLEARING BY THURSDAY MORNING WHILE THE REST OF THE FCST AREA REMAINS OVERCAST. THE LOW CLOUDS APPEAR TO BE OVERDONE IN THE NAM...GFS AND RAP MODELS BUT GIVEN THE UPSLOPE EAST AND SOUTHEAST WINDS DEVELOPING OR FORECAST TO DEVELOP...THESE MODELS MAY BE TOO FAST. OVERALL THE FORECAST CALLS FOR THE CLOUDS TO REMAIN LOCKED IN TODAY AND TONIGHT. THE LIGHT SNOW FORECAST APPEARS TO BE ON TRACK WITH NO SFC OBS REPORTING LESS THAN 1 MILE VISIBILITY OVERNIGHT AND RADAR SUGGESTS THE AREA OF SNOW IS MOVING OFF TO THE EAST. THE FORECAST CONTINUES LIGHT SNOW THIS MORNING WITH FLURRIES THROUGH EARLY AFTERNOON. NOTE THAT SEVERAL MODELS FORECAST 2 INCH SNOW TOTALS IN PLACES BUT A LOOK AT THE NEDOR CAMS INDICATES LESS THAN AN INCH ACCUMULATIONS AT ALL LOCATIONS VISIBLE AND NONE OF THE CAMS SUGGESTED MODERATE SNOW WAS FALLING. HIGH TEMPERATURES TODAY SHOULD RISE INTO THE UPPER TEENS NEAR HIGHWAY 281 WITH WARMER READINGS RISING TO THE LOWER 30S WESTWARD ACROSS SOUTHWESTERN NEB AND THE ERN PANHANDLE. LOWS TONIGHT FALL INTO TEENS. A 30 TO 40 KT LOW LEVEL JET WILL BE DEVELOPING TONIGHT AND THIS IN COMBINATION WITH THE CLOUD COVER SHOULD KEEP LOWS ON THE WARM SIDE. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 343 AM CST WED JAN 8 2014 ROLLER COAST OF TEMPS CONTINUE WITH HIGHS GOING UP FOR THURSDAY AS WAA AHEAD OF THE NEXT APPROACHING WEAK TROUGH. MOSTLY SUNNY SKIES AND HIGHS IN THE MID 30S EAST TO LOWER 40S SW. WILL NEED TO MONITOR EXISTING SNOW AS AN INCH OR SO MAY CAUSE TEMPS TO BE LOWER THAN CURRENT FORECAST BY A FEW DEGREES...HOWEVER SW WINDS IN THE 15 TO 25 MPH RANGE WHICH WILL HELP IN MIXING THE LOWER LEVELS. UPPER LEVEL TROUGH TO MOVE ACROSS THE HIGH PLAINS ON FRIDAY. SFC LOW TRACKS FROM NW TX TO THE NE...WHICH IS IN GOOD AGREEMENT WITH THE MODELS. LIFT/PRECIP DOES SEE MINOR PATH ADJUSTMENTS...HOWEVER MODELS ALL KEEP IT TO THE SE OF THE CWA. AS WINDS BECOME NW DURING THE DAY...A BRIEF MIXING WILL STILL HELP TO WARM TEMPS TO SEASONAL NORMS...POSSIBLY EVEN WARMER. UPPER LEVEL TROUGH WILL PUSH EAST BY SATURDAY WITH STRONG WAA. TEMPS FRIDAY NIGHT COULD BE EARLY...PENDING SOME MINOR TIMING ADJUSTMENTS TO ARRIVAL OF WARMER AIR. EITHER WAY...WARMER FOR SATURDAY WITH 40S FOR MOST AREAS...AND EVEN 50 FOR SW. BY SATURDAY NIGHT THE NEXT SHORT WAVE WILL BE PUSHING ACROSS THE ROCKIES. INCREASING CLOUDS SHOULD HOLD TEMPS WELL ABOVE NORMAL...WITH MID 20S TO AROUND 30 EXPECTED SUNDAY MORN. AS THE WAVE MOVES ACROSS SUNDAY MODELS HAVE FAIRLY STRONG WINDS ALOFT...WITH 850 MB WINDS NEAR 50 KTS. MODELS DO NOT MIX ALL THIS DOWN...HOWEVER DO EXPECT A WINDY DAY AND WILL MONITOR FOR POTENTIAL ADVISORY CONDITIONS. ANOTHER ISSUE WILL BE SOME WEAK LIFT WITH THE WAVE. MOISTURE IS LIMITED INITIALLY AND WILL BE A TOP DOWN SATURATION. ANOTHER ISSUE IS TEMPS WITH THIS WAVE. STILL SEEING SOME WARM AIR AT THE SURFACE WITH GUIDANCE IN AGREEMENT WITH HIGHS WARMING INTO THE 40S. LONG RANGE SOUNDINGS WOULD SUGGEST SNOW EARLY IN THE DAY...WITH WARMING TEMPS AND A CHANGE OVER TO RAIN. FOR NEXT WEEK...RIDGE AMPLIFIES OUT WEST...ALTHOUGH SOME MODELS DISAGREEMENT WITH THE STRENGTH. GFS IS WEAKER WITH THE RIDGE AND ALLOWS ANOTHER CLIPPER TO BACK ACROSS THE HIGH PLAINS ON TUESDAY...WHILE THE EC IS A LITTLE STRONG WITH THE RIDGE AND KEEPS THE CLIPPER TO THE NORTHEAST. PENDING HOW FAR TO THE SW THE CLIPPER DOES PUSHES...WILL PLAY A BIG PART TO THE FORECAST. THUS FOR EARLY NEXT WEEK FORECAST HAS LOW CONFIDENCE. THOUGHT IS FOR THE WARMER/DRIER AIR TO WIN...AS MOST OF THE WINTER THE BULK OF THE WAVES HAVE GONE EAST OF THE AREA. THAT SAID...COOLER AIR AND POSSIBLY SOME LIGHT PRECIP /FLURRIES OR SPRINKLES/ CAN NOT BE RULED OUT FOR EARLY NEXT WEEK AND WILL NEED TO BE WATCHED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1122 PM CST TUE JAN 7 2014 WIDESPREAD CEILINGS LESS THAN 3000 FEET AGL ARE EXPECTED IN NORTHERN NEBRASKA WITH AREAS OF 1000 FEET OR LOWER. THE COVERAGE OF THE INSTRUMENT CEILINGS WILL BE LESS THAN 30 PERCENT. THEREFORE WE WILL NOT INCLUDE IT IN THE POINT FORECAST FOR VTN. VISIBILITY BELOW 3SM IS LIKELY AT LEAST INTERMITTENTLY. THE INTERMITTENT INSTRUMENT VISIBILITY CONTINUE AS LATE AS 11Z. AREAS OF LIGHT SNOW AND VISIBILITY BELOW 3SM ARE EXPECTED NORTH OF BBW-AIA. IN THE REST OF CENTRAL AND SOUTHWEST NEBRASKA...CEILINGS AND VISIBILITY WILL BE ABOVE 3000 FEET AGL AND 3SM OR HIGHER. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1021 PM EST THU JAN 9 2014 .SYNOPSIS...A MOIST SOUTHERLY RETURN FLOW WILL DEVELOP THIS EVENING INTO TONIGHT AS HIGH PRESSURE MOVES OFFSHORE THE CAROLINA COAST. A COLD FRONT WILL APPROACH THE MOUNTAINS FROM THE WEST LATE FRIDAY AND FRIDAY NIGHT...THEN TRACK ACROSS THE CAROLINAS ON SATURDAY. && .NEAR TERM /TONIGHT THROUGH FRIDAY NIGHT/... AS OF 930 PM THURSDAY... TONIGHT: A DETERIORATING SHORTWAVE MOVING THROUGH THE OHIO VALLEY HAS STRENGTHENED THE PRESSURE GRADIENT BETWEEN ITSELF AND THE SURFACE HIGH OVER THE MID-ATLANTIC. STRONG WARM AIR ADVECTION...EASILY DEPICTED BY A VERY LARGE WARM NOSE AT 925 MB HAS CONTINUED TO CHARGE NORTHWARD THIS EVENING AND WILL CONTINUE TO DO SO OVERNIGHT. THIS WILL HELP TO LIMIT THE THREAT OF ANY FREEZING RAIN IN THE TRIAD OVERNIGHT. CURRENT RUN OF THE RAP MODEL HAS TEMPERATURES ONLY DOWN TO ABOUT 39 DEGREES OR SO IN THE TRIAD AND 37 IN ROXBORO BEFORE THE ONSET OF PRECIPITATION AND THE 00Z RUN OF THE NAM HAS ABOUT 35 DEGREES AND BOTH MODELS HAVE WETBULB TEMPERATURES AT ABOUT THE SAME. AS FAR AS OBSERVATIONS ARE CONCERNED AS OF 2Z KINT WAS RUNNING AT 42 DEGREES WITH A DEWPOINT OF 14 BUT DEWPOINTS JUST A COUNTY SOUTHWARD IN THE MID 20S WHICH WILL BE ADVECTING NORTHWARDS OVER THE NEXT COUPLE OF HOURS. AT THIS POINT HAVE DECIDED AGAINST AN ADVISORY FOR FREEZING WITH FAIRLY HIGH CONFIDENCE THAT NONE WILL OCCUR AND EVEN IF SO...IMPACTS WOULD BE VERY MINIMAL TO NONE AT ALL. WILL ADJUST MINIMUM TEMPERATURES UPWARDS WITH NEXT UPDATE...MID TO UPPER 30S ACROSS THE AREA. ALTHOUGH FREEZING PRECIPITATION IS NOT EXPECTED...STRONG ISENTROPIC LIFT AND THE ADVECTION OF WARM MOIST LOW LEVEL AIR WILL BRING PRECIPITATION MAINLY TO THE WESTERN PIEDMONT WITH THE RAP SHOWING FIRST ACCUMULATIONS IN THE SW AFTER 6Z AND SPREADING UP INTO THE TRIAD BY 8 OR 9Z. CURRENT RADAR SHOWS OUR FIRST RETURNS OF THE NIGHT BUT THIS IS IN ALL LIKELIHOOD NOT YET REACHING THE GROUND. IN GENERAL THE EAST WILL BE DRY COMPARED TO THE WEST BUT CANNOT RULE OUT LIGHT RAIN EVEN IN EASTERN LOCALS BY DAYBREAK. -ELLIS FRIDAY AND FRIDAY NIGHT: THE BEST SURGE OF ISENTROPIC LIFT LOOKS TO MAXIMIZE ACROSS THE AREA BY LATE MORNING BEFORE LIFTING OFF TO THE NORTH...WITH CONTINUED BROAD WAA THROUGH THE REMAINDER OF THE DAY. SO WE COULD BE LOOKING AT A LULL IN MEASURABLE PRECIP BY NOON WITH MORE IN THE WAY OF DRIZZLE THROUGH THE AFTERNOON AND EVENING...ESPECIALLY IN THE EAST REMOVED FROM THE HEART OF THE DAMMING AIRMASS AND BETTER FGEN GRADIENT ACROSS THE WESTERN PIEDMONT. TEMPERATURES: WILL SEE THE TYPICAL SHARP NW-SE TEMPERATURE GRADIENT ASSOCIATED WITH CAD EVENTS...RANGING FROM MID TO UPPER 30S IN THE TRIAD TO MID AND UPPER 50S IN THE FAR SE COASTAL PLAIN. MODELS INDICATE WEDGE WILL ERODE OVERNIGHT FRIDAY NIGHT WITH LOW TEMPS SAT MORNING LIKELY OCCURRING AT MIDNIGHT WITH RISING TEMPS THEREAFTER. WILL INDICATE TEMPS RISING INTO THE MID/UPPER 50S TO LOWER 60S ALONG/EAST OF HWY 1 (WARMEST SE COASTAL PLAIN) TO MID/UPPER 40S IN THE TRIAD. -CBL && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 225 PM THURSDAY... FOR SAT/SAT NIGHT: A WET AND POTENTIALLY STORMY DAY. THE WARM FRONTAL ZONE WILL LIKELY STILL BE SITUATED SE OF THE TRIAD AT DAYBREAK BUT WE SHOULD BE FULLY IN THE WARM SECTOR BY AROUND 18Z SAT AS THE WARM FRONTAL MOMENTUM SHOULD EASILY OVERTAKE THE THINNING STABLE POOL. (THE GFS IS A FEW HOURS SLOWER THAN THE NAM WITH ITS WARM FRONTAL PASSAGE.) DEEP MID LEVEL TROUGHING THROUGH THE CENTRAL CONUS WILL SHIFT EASTWARD THROUGH THE EASTERN CONUS SAT/SAT NIGHT... WITH SURFACE COLD FRONT PASSAGE THROUGH NC SAT AFTERNOON AND EVENING. CERTAINTY IS HIGH THAT WE`LL SEE WIDESPREAD SHOWERS AHEAD OF THIS FRONT GIVEN THE SURGE IN MOISTURE WITH A STRONG GULF FEED AND INCOMING PW VALUES OF 1.3-1.7. VIGOROUS DYNAMIC FORCING WILL CONTRIBUTE TO ASCENT WITH STRENGTHENING UPPER LEVEL DIVERGENCE AND MID LEVEL DPVA... 500 MB WINDS OVER 500 MB... 12-HR HEIGHT FALLS OF 180-240 METERS... AND AN 850 MB JET FROM THE SW INTENSIFYING TO 50- 60 KTS. THESE POTENT DYNAMICS APPEAR TO MAXIMIZE OVER NC AROUND 18Z (GIVE OR TAKE AN HOUR OR TWO)... WHEN WE ALSO SEE RISING MODEL FORECAST INSTABILITY... WITH THE NAM DEPICTING 400-800 J/KG OF SURFACE CAPE ALONG/EAST OF HIGHWAY 1. LOW LEVEL SHEAR RAMPS UP EARLY SAT AS WELL... WITH 0-1 KM SHEAR TOPPING OUT AT 45-50 KTS (HIGHEST IN THE PIEDMONT) SAT AFTERNOON... AND LOW LCLS. ALL OF THIS EQUATES TO A RISK OF STRONG FAST-MOVING BOWING SEGMENTS AND PERHAPS A SUPERCELL OR TWO... PROVIDED THE PREDICTED INSTABILITY CAN BE REALIZED AND WE DO INDEED SEE SURFACE DEW POINTS IN THE 60S AS MODELS GENERALLY AGREE WILL HAPPEN. THE ONE CAVEAT IS THE POSSIBILITY OF MORNING SHOWERS PRECEDING THE PRIMARY BAND OF SHOWERS... AS THIS MAY TEMPER INSTABILITY ESPECIALLY IN THE WRN HALF OF THE CWA WHERE THE LOW LEVEL SHEAR WILL BE STRONGEST. WILL ADD A MENTION OF THUNDER SAT... ESPECIALLY EAST... AND ADD A MENTION OF POSSIBLE STRONG STORMS TO THE HAZARDOUS WEATHER OUTLOOK. EXPECT MOSTLY CLOUDY TO CLOUDY SKIES THROUGH THE DAY... QUITE WINDY WITH SUSTAINED WINDS OF 15-20 MPH GUSTING TO 35 MPH (AND OCCASIONALLY HIGHER)... AND CATEGORICAL POPS. BASED ON MODEL GUIDANCE AND SREF PROBABILITIES... RAINFALL AMOUNTS ARE EXPECTED TO REACH AROUND 1.0- 1.25 INCHES FOR THE ENTIRE EVENT. EXPECT A SLOWER TEMP RISE IN THE TRIAD UNTIL THE VERY SHALLOW SURFACE-BASED STABLE POOL IS ERODED THERE... BUT OVERALL IT SHOULD BE A MILD DAY WITH HIGHS FROM THE LOW 60S NW TO LOW 70S SE. BOTH THE NAM AND GFS INDICATE CLEARING SKIES SAT NIGHT ALTHOUGH THE GFS IS MUCH FASTER WITH DEEP DRYING TAKING PLACE WHILE THE NAM IS SLOWER AND HOLDS ONTO PLENTY OF MOISTURE BELOW 600 MB WELL INTO THE EVENING. THE NAM ALSO STAYS WELL-MIXED FOR SEVERAL HOURS JUST BEHIND THE COLD FRONT AS THE 925-700 MB LAYER COOLS WITH THE DELAY IN SURFACE COOLING... AND THIS WOULD SUGGEST A FEW SHALLOW SHOWERS BEHIND THE FRONT. BUT IN EITHER CASE WE SHOULD SEE CLEARING AFTER MIDNIGHT WITH DEEP DRYING. WITH THE MIXING HOLDING THROUGH THE NIGHT... EXPECT WINDS TO STAY UP... AND THIS STIRRING WILL SOMEWHAT OFFSET THE COLD AIR ADVECTION AND HINDER THE DROP IN TEMPS. LOWS 40-49. FOR SUN/SUN NIGHT: MODELS INDICATE IMPRESSIVE HEIGHT RISES OF 220- 260 M BEHIND THE TROUGH AND STRONG MID LEVEL SUBSIDENCE AND WARMING STARTING IN THE PREDAWN HOURS SUNDAY. EXPECT CLEAR SKIES WITH MODIFIED SURFACE HIGH PRESSURE BUILDING IN FROM THE SW. THICKNESSES WILL HAVE COOLED MARKEDLY FROM SATURDAY BUT ARE STILL LIKELY TO BE ABOUT 5-10 M ABOVE NORMAL... EQUATING TO HIGHS OF 53-62... A TAD UNDER STATISTICAL GUIDANCE. THE SURFACE HIGH SHIFTS QUICKLY OFF THE SE COAST SUN NIGHT WITHIN A PROGRESSIVE LONGWAVE PATTERN ACROSS THE CONUS. AS OUR NEXT LONGWAVE TROUGH SHIFTS THROUGH THE CENTRAL STATES SUN NIGHT WITH A SHOT OF SOUTHERN STREAM ENERGY MOVING IN FROM THE SW... WE`LL SEE INCREASING SOUTHWEST FLOW ALOFT OVER NC RESULTING IN INCREASING AND THICKENING HIGH CLOUDS OVERNIGHT. LOWS 34-40. -GIH && .LONG TERM /MONDAY THROUGH THURSDAY... AS OF 245 PM THURSDAY... CHALLENGING FORECAST FOR THE EARLY TO MIDDLE PART OF NEXT WEEK AS SOME MODEL DISAGREEMENT EMERGES. THE LONGWAVE TROUGH OVER THE CENTRAL US EARLY MONDAY MORNING PROGRESSES EASTWARD THROUGH MON NIGHT WITH ENERGY DIGGING INTO THE TROUGH BASE... MUCH MORE DEEPLY OVER THE DEEP SOUTH ON THE ECMWF THAN THE GFS. AS A RESULT... THE ECMWF PULLS THE OLD FRONTAL ZONE TO OUR SOUTH WELL TO THE NNW AND BACK INTO NC AS A WARM FRONT BY LATE MON NIGHT... WITH A STRONG SURFACE CYCLONE MOVING NE THROUGH NC TUE MORNING. MEANWHILE... THE WEAKER AND FASTER GFS BRINGS THE FRONTAL ZONE BACK NW ONLY TO THE COASTAL CAROLINAS WITH A COLD FRONT (AND NO STRONG CYCLONE) SHIFTING THROUGH NC MON NIGHT. TOUGH TO PICK OUT A WINNER BETWEEN THESE TWO CAMPS... PARTICULARLY CONSIDERING THAT BOTH HAVE VARYING DEGREES OF POLAR STREAM ENERGY DIVING IN THE BACK SIDE OF THE LONGWAVE TROUGH EARLY TUE... WHICH SERVES TO DEEPEN THE TROUGH OVER THE EASTERN CONUS WED/THU. GIVEN THE UNCERTAINTY... WILL AVOID FORECASTING ANY EXTREMES... AND STICK WITH A CHANCE OF RAIN STARTING WITH THE APPROACH OF THE FRONT MON NIGHT... LASTING INTO TUE EVENING. BOTH THE GFS AND ECMWF SWING THE TROUGH BASE THROUGH NC WED WITH AT LEAST SOME CLOUDINESS AND POTENTIALLY SOME PRECIP AS WELL. THESE DETERMINISTIC MODELS SUGGEST THAT IT COULD BE A QUICK SHOT OF LIGHT MIXED RAIN/SNOW BASED ON FORECAST PARTIAL THICKNESSES... HOWEVER GIVEN THAT WE COULD HAVE SUBSTANTIAL DOWNSLOPE FLOW COMPONENT ESPECIALLY WITH A WEAKER SYSTEM... WILL PUT IN CLOUDS FOR NOW BUT HOLD OFF ON ANY PRECIP CHANCES ON WED. CLEARING BY THU WITH SOUTHERN STREAM HIGH PRESSURE BUILDING INTO THE SOUTHEAST. WILL KEEP TEMPS WITHIN A CATEGORY OF CLIMATOLOGY THROUGHOUT THIS PERIOD... BUT CONFIDENCE IS NOT HIGH... AS A MUCH STRONGER OR WEAKER SYSTEM COULD HAVE LARGE EFFECTS ON TEMPS. -GIH && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AS OF 730 PM THURSDAY... 24-HR TAF PERIOD: VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE REMAINDER OF THE EVENING... BEFORE WARM MOIST AIR OVERSPREAD THE SHALLOW DRY SURFACE AIRMASS. THIS WILL SET THE STAGE FOR A CAD EVENT... WITH LOWERING CIGS AND RAIN FOR EARLY FRIDAY MORNING... AND GENERALLY CONTINUING THROUGH THE REMAINDER OF THE 24 HOUR TAF FORECAST. EXPECT KGSO/KINT MAY SEE SOME RAIN AND SUB VFR CIGS SPREAD INTO THE AREA IN THE 06-09Z TIME FRAME... WITH LIFR CONDITIONS POSSIBLE BY AROUND 12Z... WITH THE SAME EXPECTED AT KRDU... BUT OCCURRING A FEW HOURS LATER IN TIME. ONCE LIFR/IFR CONDITIONS DEVELOP AT KGSO/KINT/KRDU EXPECT THEY WILL PERSIST THROUGH THE REMAINDER OF THE 24 HOUR TAF PERIOD ALONG WITH PERIODS OF RAIN/DRIZZLE. AT KRWI AND KFAY.... WE SHOULD SEE RAIN AND SUB-VFR CIGS SPREAD INTO THESE AREAS CLOSER TO 12Z. THE CIGS ARE EXPECTED TO LOWER TO LOW END MVFR TO IFR RANGE. HOWEVER... SOME IMPROVEMENT IS POSSIBLE LATE IN THE DAY. WHILE DEVELOPMENT OF SUB-VFR CONDITIONS IS HIGH AT KFAY AND KRWI... THE POSSIBLE SCATTERING OF THE CAD AIRMASS AND SUBSEQUENT LIFTING OF IFR/LOW END MVFR CIGS IS LOW (AS SOME GUIDANCES IS SHOWING VFR CONDITIONS RETURNING BY MID AFTERNOON). THUS... WILL MAINTAIN THESE CONDITIONS IN THE TAFS FOR THE ENTIRE 24 HOUR TAF PERIOD AS WELL. LOOKING AHEAD: WIDESPREAD ADVERSE AVIATION CONDITIONS ARE EXPECTED TO PERSIST THROUGH SATURDAY NIGHT IN ASSOCIATION WITH A COLD FRONT ACCOMPANYING BAND OF SHOWERS...AND PERHAPS A THUNDERSTORM OR TWO ACROSS EASTERN TERMINALS. THERE COULD BE BRIEF PERIOD LATE FRIDAY/FRIDAY EVENING THAT WILL WILL BE FAVORABLE FOR LOW-LEVEL WIND SHEAR AS 30KT H9 SOUTHERLY LOW-LEVEL FLOW STRENGTHENS ATOP THE COLD AIR DAMMING WEDGE INITIALLY IN PLACE...MAINLY AT THE INT/GSO TERMINALS...FOLLOWED BY STRONG GUSTY SOUTHERLY WINDS DURING THE DAY ON SATURDAY. VFR CONDITIONS ARE EXPECTED TO RETURN BEHIND THE COLD FRONT LATE SATURDAY NIGHT THROUGH MONDAY WITH MILD HIGH PRESSURE BUILDING IN FROM THE SW. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...ELLIS/CBL SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...BSD/CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1006 PM EST THU JAN 9 2014 .SYNOPSIS...A MOIST SOUTHERLY RETURN FLOW WILL DEVELOP THIS EVENING INTO TONIGHT AS HIGH PRESSURE MOVES OFFSHORE THE CAROLINA COAST. A COLD FRONT WILL APPROACH THE MOUNTAINS FROM THE WEST LATE FRIDAY AND FRIDAY NIGHT...THEN TRACK ACROSS THE CAROLINAS ON SATURDAY. && .NEAR TERM /TONIGHT THROUGH FRIDAY NIGHT/... AS OF 930 PM THURSDAY... TONIGHT: A DETERIORATING SHORTWAVE MOVING THROUGH THE OHIO VALLEY HAS STRENGTHENED THE PRESSURE GRADIENT BETWEEN ITSELF AND THE SURFACE HIGH OVER THE MID-ATLANTIC. THIS WILL HELP TO EVENTUALLY BREAK DOWN THE HYBRID CAD WEDGE FRONT OVER THE WESTERN PIEDMONT. IN ADDITION...STRONG WARM AIR ADVECTION...EASILY DEPICTED BY A VERY LARGE WARM NOSE AT 925 MB HAS CONTINUED TO CHARGE NORTHWARD THIS EVENING AND WILL CONTINUE TO DO SO OVERNIGHT. THIS WILL HELP TO LIMIT THE THREAT OF ANY FREEZING RAIN IN THE TRIAD OVERNIGHT. CURRENT RUN OF THE RAP MODEL HAS TEMPERATURES ONLY DOWN TO ABOUT 39 DEGREES OR SO IN THE TRIAD AND 37 IN ROXBORO BEFORE THE ONSET OF PRECIPITATION AND THE 00Z RUN OF THE NAM HAS ABOUT 35 DEGREES AND BOTH MODELS HAVE WETBULB TEMPERATURES AT ABOUT THE SAME. AS FAR AS OBSERVATIONS ARE CONCERNED AS OF 2Z KINT WAS RUNNING AT 42 DEGREES WITH A DEWPOINT OF 14 BUT DEWPOINTS JUST A COUNTY SOUTHWARD IN THE MID 20S WHICH WILL BE ADVECTING NORTHWARDS OVER THE NEXT COUPLE OF HOURS. AT THIS POINT HAVE DECIDED AGAINST AN ADVISORY FOR FREEZING WITH FAIRLY HIGH CONFIDENCE THAT NONE WILL OCCUR AND EVEN IF SO...IMPACTS WOULD BE VERY MINIMAL TO NONE AT ALL. WILL ADJUST MINIMUM TEMPERATURES UPWARDS WITH NEXT UPDATE...MID TO UPPER 30S ACROSS THE AREA. ALTHOUGH FREEZING PRECIPITATION IS NOT EXPECTED...STRONG ISENTROPIC LIFT AND THE ADVECTION OF WARM MOIST LOW LEVEL AIR WILL BRING PRECIPITATION MAINLY TO THE WESTERN PIEDMONT WITH THE RAP SHOWING FIRST ACCUMULATIONS IN THE SW AFTER 6Z AND SPREADING UP INTO THE TRIAD BY 8 OR 9Z. CURRENT RADAR SHOWS OUR FIRST RETURNS OF THE NIGHT BUT THIS IS IN ALL LIKELIHOOD NOT YET REACHING THE GROUND. IN GENERAL THE EAST WILL BE DRY COMPARED TO THE WEST BUT CANNOT RULE OUT LIGHT RAIN EVEN IN EASTERN LOCALS BY DAYBREAK. -ELLIS FRIDAY AND FRIDAY NIGHT: THE BEST SURGE OF ISENTROPIC LIFT LOOKS TO MAXIMIZE ACROSS THE AREA BY LATE MORNING BEFORE LIFTING OFF TO THE NORTH...WITH CONTINUED BROAD WAA THROUGH THE REMAINDER OF THE DAY. SO WE COULD BE LOOKING AT A LULL IN MEASURABLE PRECIP BY NOON WITH MORE IN THE WAY OF DRIZZLE THROUGH THE AFTERNOON AND EVENING...ESPECIALLY IN THE EAST REMOVED FROM THE HEART OF THE DAMMING AIRMASS AND BETTER FGEN GRADIENT ACROSS THE WESTERN PIEDMONT. TEMPERATURES: WILL SEE THE TYPICAL SHARP NW-SE TEMPERATURE GRADIENT ASSOCIATED WITH CAD EVENTS...RANGING FROM MID TO UPPER 30S IN THE TRIAD TO MID AND UPPER 50S IN THE FAR SE COASTAL PLAIN. MODELS INDICATE WEDGE WILL ERODE OVERNIGHT FRIDAY NIGHT WITH LOW TEMPS SAT MORNING LIKELY OCCURRING AT MIDNIGHT WITH RISING TEMPS THEREAFTER. WILL INDICATE TEMPS RISING INTO THE MID/UPPER 50S TO LOWER 60S ALONG/EAST OF HWY 1 (WARMEST SE COASTAL PLAIN) TO MID/UPPER 40S IN THE TRIAD. -CBL && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 225 PM THURSDAY... FOR SAT/SAT NIGHT: A WET AND POTENTIALLY STORMY DAY. THE WARM FRONTAL ZONE WILL LIKELY STILL BE SITUATED SE OF THE TRIAD AT DAYBREAK BUT WE SHOULD BE FULLY IN THE WARM SECTOR BY AROUND 18Z SAT AS THE WARM FRONTAL MOMENTUM SHOULD EASILY OVERTAKE THE THINNING STABLE POOL. (THE GFS IS A FEW HOURS SLOWER THAN THE NAM WITH ITS WARM FRONTAL PASSAGE.) DEEP MID LEVEL TROUGHING THROUGH THE CENTRAL CONUS WILL SHIFT EASTWARD THROUGH THE EASTERN CONUS SAT/SAT NIGHT... WITH SURFACE COLD FRONT PASSAGE THROUGH NC SAT AFTERNOON AND EVENING. CERTAINTY IS HIGH THAT WE`LL SEE WIDESPREAD SHOWERS AHEAD OF THIS FRONT GIVEN THE SURGE IN MOISTURE WITH A STRONG GULF FEED AND INCOMING PW VALUES OF 1.3-1.7. VIGOROUS DYNAMIC FORCING WILL CONTRIBUTE TO ASCENT WITH STRENGTHENING UPPER LEVEL DIVERGENCE AND MID LEVEL DPVA... 500 MB WINDS OVER 500 MB... 12-HR HEIGHT FALLS OF 180-240 METERS... AND AN 850 MB JET FROM THE SW INTENSIFYING TO 50- 60 KTS. THESE POTENT DYNAMICS APPEAR TO MAXIMIZE OVER NC AROUND 18Z (GIVE OR TAKE AN HOUR OR TWO)... WHEN WE ALSO SEE RISING MODEL FORECAST INSTABILITY... WITH THE NAM DEPICTING 400-800 J/KG OF SURFACE CAPE ALONG/EAST OF HIGHWAY 1. LOW LEVEL SHEAR RAMPS UP EARLY SAT AS WELL... WITH 0-1 KM SHEAR TOPPING OUT AT 45-50 KTS (HIGHEST IN THE PIEDMONT) SAT AFTERNOON... AND LOW LCLS. ALL OF THIS EQUATES TO A RISK OF STRONG FAST-MOVING BOWING SEGMENTS AND PERHAPS A SUPERCELL OR TWO... PROVIDED THE PREDICTED INSTABILITY CAN BE REALIZED AND WE DO INDEED SEE SURFACE DEW POINTS IN THE 60S AS MODELS GENERALLY AGREE WILL HAPPEN. THE ONE CAVEAT IS THE POSSIBILITY OF MORNING SHOWERS PRECEDING THE PRIMARY BAND OF SHOWERS... AS THIS MAY TEMPER INSTABILITY ESPECIALLY IN THE WRN HALF OF THE CWA WHERE THE LOW LEVEL SHEAR WILL BE STRONGEST. WILL ADD A MENTION OF THUNDER SAT... ESPECIALLY EAST... AND ADD A MENTION OF POSSIBLE STRONG STORMS TO THE HAZARDOUS WEATHER OUTLOOK. EXPECT MOSTLY CLOUDY TO CLOUDY SKIES THROUGH THE DAY... QUITE WINDY WITH SUSTAINED WINDS OF 15-20 MPH GUSTING TO 35 MPH (AND OCCASIONALLY HIGHER)... AND CATEGORICAL POPS. BASED ON MODEL GUIDANCE AND SREF PROBABILITIES... RAINFALL AMOUNTS ARE EXPECTED TO REACH AROUND 1.0- 1.25 INCHES FOR THE ENTIRE EVENT. EXPECT A SLOWER TEMP RISE IN THE TRIAD UNTIL THE VERY SHALLOW SURFACE-BASED STABLE POOL IS ERODED THERE... BUT OVERALL IT SHOULD BE A MILD DAY WITH HIGHS FROM THE LOW 60S NW TO LOW 70S SE. BOTH THE NAM AND GFS INDICATE CLEARING SKIES SAT NIGHT ALTHOUGH THE GFS IS MUCH FASTER WITH DEEP DRYING TAKING PLACE WHILE THE NAM IS SLOWER AND HOLDS ONTO PLENTY OF MOISTURE BELOW 600 MB WELL INTO THE EVENING. THE NAM ALSO STAYS WELL-MIXED FOR SEVERAL HOURS JUST BEHIND THE COLD FRONT AS THE 925-700 MB LAYER COOLS WITH THE DELAY IN SURFACE COOLING... AND THIS WOULD SUGGEST A FEW SHALLOW SHOWERS BEHIND THE FRONT. BUT IN EITHER CASE WE SHOULD SEE CLEARING AFTER MIDNIGHT WITH DEEP DRYING. WITH THE MIXING HOLDING THROUGH THE NIGHT... EXPECT WINDS TO STAY UP... AND THIS STIRRING WILL SOMEWHAT OFFSET THE COLD AIR ADVECTION AND HINDER THE DROP IN TEMPS. LOWS 40-49. FOR SUN/SUN NIGHT: MODELS INDICATE IMPRESSIVE HEIGHT RISES OF 220- 260 M BEHIND THE TROUGH AND STRONG MID LEVEL SUBSIDENCE AND WARMING STARTING IN THE PREDAWN HOURS SUNDAY. EXPECT CLEAR SKIES WITH MODIFIED SURFACE HIGH PRESSURE BUILDING IN FROM THE SW. THICKNESSES WILL HAVE COOLED MARKEDLY FROM SATURDAY BUT ARE STILL LIKELY TO BE ABOUT 5-10 M ABOVE NORMAL... EQUATING TO HIGHS OF 53-62... A TAD UNDER STATISTICAL GUIDANCE. THE SURFACE HIGH SHIFTS QUICKLY OFF THE SE COAST SUN NIGHT WITHIN A PROGRESSIVE LONGWAVE PATTERN ACROSS THE CONUS. AS OUR NEXT LONGWAVE TROUGH SHIFTS THROUGH THE CENTRAL STATES SUN NIGHT WITH A SHOT OF SOUTHERN STREAM ENERGY MOVING IN FROM THE SW... WE`LL SEE INCREASING SOUTHWEST FLOW ALOFT OVER NC RESULTING IN INCREASING AND THICKENING HIGH CLOUDS OVERNIGHT. LOWS 34-40. -GIH && .LONG TERM /MONDAY THROUGH THURSDAY... AS OF 245 PM THURSDAY... CHALLENGING FORECAST FOR THE EARLY TO MIDDLE PART OF NEXT WEEK AS SOME MODEL DISAGREEMENT EMERGES. THE LONGWAVE TROUGH OVER THE CENTRAL US EARLY MONDAY MORNING PROGRESSES EASTWARD THROUGH MON NIGHT WITH ENERGY DIGGING INTO THE TROUGH BASE... MUCH MORE DEEPLY OVER THE DEEP SOUTH ON THE ECMWF THAN THE GFS. AS A RESULT... THE ECMWF PULLS THE OLD FRONTAL ZONE TO OUR SOUTH WELL TO THE NNW AND BACK INTO NC AS A WARM FRONT BY LATE MON NIGHT... WITH A STRONG SURFACE CYCLONE MOVING NE THROUGH NC TUE MORNING. MEANWHILE... THE WEAKER AND FASTER GFS BRINGS THE FRONTAL ZONE BACK NW ONLY TO THE COASTAL CAROLINAS WITH A COLD FRONT (AND NO STRONG CYCLONE) SHIFTING THROUGH NC MON NIGHT. TOUGH TO PICK OUT A WINNER BETWEEN THESE TWO CAMPS... PARTICULARLY CONSIDERING THAT BOTH HAVE VARYING DEGREES OF POLAR STREAM ENERGY DIVING IN THE BACK SIDE OF THE LONGWAVE TROUGH EARLY TUE... WHICH SERVES TO DEEPEN THE TROUGH OVER THE EASTERN CONUS WED/THU. GIVEN THE UNCERTAINTY... WILL AVOID FORECASTING ANY EXTREMES... AND STICK WITH A CHANCE OF RAIN STARTING WITH THE APPROACH OF THE FRONT MON NIGHT... LASTING INTO TUE EVENING. BOTH THE GFS AND ECMWF SWING THE TROUGH BASE THROUGH NC WED WITH AT LEAST SOME CLOUDINESS AND POTENTIALLY SOME PRECIP AS WELL. THESE DETERMINISTIC MODELS SUGGEST THAT IT COULD BE A QUICK SHOT OF LIGHT MIXED RAIN/SNOW BASED ON FORECAST PARTIAL THICKNESSES... HOWEVER GIVEN THAT WE COULD HAVE SUBSTANTIAL DOWNSLOPE FLOW COMPONENT ESPECIALLY WITH A WEAKER SYSTEM... WILL PUT IN CLOUDS FOR NOW BUT HOLD OFF ON ANY PRECIP CHANCES ON WED. CLEARING BY THU WITH SOUTHERN STREAM HIGH PRESSURE BUILDING INTO THE SOUTHEAST. WILL KEEP TEMPS WITHIN A CATEGORY OF CLIMATOLOGY THROUGHOUT THIS PERIOD... BUT CONFIDENCE IS NOT HIGH... AS A MUCH STRONGER OR WEAKER SYSTEM COULD HAVE LARGE EFFECTS ON TEMPS. -GIH && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... AS OF 730 PM THURSDAY... 24-HR TAF PERIOD: VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE REMAINDER OF THE EVENING... BEFORE WARM MOIST AIR OVERSPREAD THE SHALLOW DRY SURFACE AIRMASS. THIS WILL SET THE STAGE FOR A CAD EVENT... WITH LOWERING CIGS AND RAIN FOR EARLY FRIDAY MORNING... AND GENERALLY CONTINUING THROUGH THE REMAINDER OF THE 24 HOUR TAF FORECAST. EXPECT KGSO/KINT MAY SEE SOME RAIN AND SUB VFR CIGS SPREAD INTO THE AREA IN THE 06-09Z TIME FRAME... WITH LIFR CONDITIONS POSSIBLE BY AROUND 12Z... WITH THE SAME EXPECTED AT KRDU... BUT OCCURRING A FEW HOURS LATER IN TIME. ONCE LIFR/IFR CONDITIONS DEVELOP AT KGSO/KINT/KRDU EXPECT THEY WILL PERSIST THROUGH THE REMAINDER OF THE 24 HOUR TAF PERIOD ALONG WITH PERIODS OF RAIN/DRIZZLE. AT KRWI AND KFAY.... WE SHOULD SEE RAIN AND SUB-VFR CIGS SPREAD INTO THESE AREAS CLOSER TO 12Z. THE CIGS ARE EXPECTED TO LOWER TO LOW END MVFR TO IFR RANGE. HOWEVER... SOME IMPROVEMENT IS POSSIBLE LATE IN THE DAY. WHILE DEVELOPMENT OF SUB-VFR CONDITIONS IS HIGH AT KFAY AND KRWI... THE POSSIBLE SCATTERING OF THE CAD AIRMASS AND SUBSEQUENT LIFTING OF IFR/LOW END MVFR CIGS IS LOW (AS SOME GUIDANCES IS SHOWING VFR CONDITIONS RETURNING BY MID AFTERNOON). THUS... WILL MAINTAIN THESE CONDITIONS IN THE TAFS FOR THE ENTIRE 24 HOUR TAF PERIOD AS WELL. LOOKING AHEAD: WIDESPREAD ADVERSE AVIATION CONDITIONS ARE EXPECTED TO PERSIST THROUGH SATURDAY NIGHT IN ASSOCIATION WITH A COLD FRONT ACCOMPANYING BAND OF SHOWERS...AND PERHAPS A THUNDERSTORM OR TWO ACROSS EASTERN TERMINALS. THERE COULD BE BRIEF PERIOD LATE FRIDAY/FRIDAY EVENING THAT WILL WILL BE FAVORABLE FOR LOW-LEVEL WIND SHEAR AS 30KT H9 SOUTHERLY LOW-LEVEL FLOW STRENGTHENS ATOP THE COLD AIR DAMMING WEDGE INITIALLY IN PLACE...MAINLY AT THE INT/GSO TERMINALS...FOLLOWED BY STRONG GUSTY SOUTHERLY WINDS DURING THE DAY ON SATURDAY. VFR CONDITIONS ARE EXPECTED TO RETURN BEHIND THE COLD FRONT LATE SATURDAY NIGHT THROUGH MONDAY WITH MILD HIGH PRESSURE BUILDING IN FROM THE SW. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...ELLIS/CBL SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...BSD/CBL
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
932 PM EST THU JAN 9 2014 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO RIDGE INTO EASTERN NC FROM THE NORTHEAST THROUGH FRIDAY WHILE A WEAK COASTAL TROUGH DEVELOPS TONIGHT THROUGH FRIDAY. A WARM FRONT WILL MOVE NORTH THROUGH THE AREA FRIDAY NIGHT. A COLD FRONT WILL MOVE THROUGH THE REGION SATURDAY NIGHT. HIGH PRESSURE WILL BUILD IN SUNDAY INTO MONDAY. A LOW PRESSURE AREA AND COLD FRONT MAY MOVE THROUGH THE AREA TUESDAY. && .NEAR TERM /UNTIL 7 AM FRIDAY MORNING/... AS OF 930 PM THU...NO SIGNIFICANT CHANGES THIS UPDATE...JUST MINOR HOURLY TEMP GRID TWEAKS BASED ON LATEST OBS. SFC HIGH PRES WILL SLIDE OFF THE MID ATLANTIC COAST TONIGHT WITH A RIDGE BUILDING ALOFT AS A MID LEVEL TROUGH DIGS ACROSS THE CENTRAL PLAINS. SOUTHERLY RETURN FLOW BRINGS WAA AND INCREASING CLOUDS THROUGH THE OVERNIGHT WITH A COASTAL TROUGH OFFSHORE BEGINNING TO PUSH INLAND LATE IN THE PERIOD. MODELS DEPICTING AN AREA OF ISENTROPIC LIFT WITH LOW COND PRES DEFICITS MOVING INTO WESTERN SECTIONS LATE AND COULD SEE LIGHT RAIN DEVELOPING BEFORE SUNRISE. MOISTURE FAIRLY SHALLOW...BELOW 700 MB...WITH DRY CONDITIONS IN THE SNOW GROWTH ZONE SO EXPECT RAINFALL TO BE LIGHT. CONSIDERED DROPPING THE SLIGHT POPS INLAND OVERNIGHT LATE...BUT DECIDED TO LET IT STAND AS IS. FCST SOUNDINGS STILL INDICATIVE OF FOG WITH A STRONG SFC BASED INVERSION BUT THINK CLOUDS WILL LIMIT FOG DEVELOPMENT OVERNIGHT. TEMPS WILL LIKELY FALL QUICKLY THIS EVENING BEFORE LEVELING OFF...THEN RISE LATE WITH INCREASING CLOUDS AND THE COASTAL TROUGH PUSHING INLAND. MIN TEMPS EXPECTED AROUND 35-40 INLAND AND 40-45 ALONG THE COAST. && .SHORT TERM /7 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... AS OF 230 PM THU...SFC HIGH PRES SLIDES FARTHER OFFSHORE BUT CONTINUES TO RIDGE INTO THE PIEDMONT WITH THE COASTAL TROUGH PUSHING TO ABOUT THE I-95 CORRIDOR BY LATE IN THE DAY. SKIES WILL BE MAINLY CLOUDY WITH OCCASIONAL LIGHT RAIN AS WAA AND ISENTROPIC LIFT CONTINUE. BEST LIFT REMAINS WEST OF THE CWA OVER THE SFC WEDGE BUT MODELS ARE DEPICTING A PERIOD OF ENHANCED ISENTROPIC LIFT WITH LOW COND PRES DEFICITS AROUND MID DAY. LOW LEVEL THICKNESSES AROUND 1360-1370M AND EXPECT MAX TEMPS IN THE LOW/MID 60S DESPITE MAINLY CLOUDY SKIES. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... AS OF 300 PM THURSDAY...MODELS REMAIN IN DECENT AGREEMENT THROUGH MONDAY...THEN HAVE TYPICAL TIMING DIFFERENCES FOR TUE-THU. MAIN CHANGE TO FCST WAS TO END PCPN FASTER SAT NIGHT/EARLY SUN WITH MODELS INDICATING FASTER FRONTAL PASSAGE...AND INCREASED POPS TO CHANCE FOR LATE MON NIGHT AND TUE MORNING WITH FRONTAL SYSTEM THAT PERIOD. COASTAL TROF WILL LIFT INLAND AS A WARM FRONT FRIDAY NIGHT WITH CONTINUED 20/30 POPS FOR PATCHY LIGHT RAIN WITH ISENT LIFT. PROGRESSIVE SHRT WV TROF WILL APPROACH SAT AND MOVE THROUGH BY EARLY SUNDAY...ACCOMPANIED BY SFC COLD FRONT. MODELS CONTINUE TO INDICATE LI -1 TO -4 IN WARM SECTOR AHEAD OF FRONT SAT AFTN...WITH STRONG WIND FIELDS SUPPORTING ISOLD SVR TSTM THREAT IF ANY STORMS CAN GET ORGANIZED. CURRENT INDICATIONS ARE THAT CLOUDINESS AND PSBL SHOWER ACTIVITY OFF WATER WELL IN ADVANCE OF FRONT WILL LIMIT DESTABILIZATION...BUT CANNOT RULE OUT ISOLATED THREAT. INCREASED POPS TO CATEGORICAL FOR SHOWERS AND SLGT CHC OF TSTMS FOR LATE SAT AFTN UNTIL 1 AM SUNDAY. DECREASING POPS OVERNIGHT WITH PCPN EXPECTED TO BE OFF COAST BY 7 AM. DRIER AND SLIGHTLY COOLER FOR SUN INTO MON BUT HIGH PRES BUILDING IN FROM SW WILL BE OF PACIFIC ORIGIN RATHER THAN ARCTIC. ANOTHER PROGRESSIVE SHRT WV FCST TO MOVE THROUGH WITH ASSCTD SFC FRONT MON NIGHT AND EARLY TUE...BUT MODEL DIFFERENCES LEAD TO BELOW NORMAL FCST CONFIDENCE. ECMWF SLIGHTLY DEEPER AND SLOWER THAN GFS...AND STUCK WITH HPC BLEND FOR NOW...INDICATING CHC POPS FOR LATE MON NIGHT INTO TUE. CLIPPER SHRT WV WILL PRODUCE A SECONDARY FRONTAL PASSAGE EARLY WED...WITH SLIGHT TAP OF COLDER AIR RESULTING IN TEMPS NEAR FREEZING AGAIN EARLY THU. TEMPS WILL AVERAGE 5 TO 15 DEGS ABOVE NORMAL INTO WED...THEN NEAR NORMAL THU. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... SHORT TERM /THROUGH FRIDAY AFTERNOON/... AS OF 655 PM THU...VFR CONDITIONS EXPECTED THROUGH THE OVERNIGHT HOURS WITH HIGH PRESSURE IN CONTROL. MID LEVEL CLOUD DECK OF THIS AFTERNOON HAS BROKEN UP AND LIFTED NE ACROSS MOST OF THE AREA BUT EXPECT ADDITIONAL MID AND HIGH CLOUDS TO ROLL IN OVERNIGHT FROM THE SW. FOG WILL BE LIMITED OVERNIGHT GIVEN CLOUD COVER AND SOME MIXING IN PLACE. HIGH PRESSURE WILL SHIFT OFF THE MID- ATLANTIC COAST FRIDAY MORNING WITH SOME COOLER AIR DAMMING AGAINST THE APPALACHIAN MOUNTAINS. THIS MAY PRODUCE LOWERS CIGS/VSBYS ACROSS PGV/ISO SITES TOMORROW DURING THE DAY. COULD SEE SOME LOWER CIGS DEVELOP BY LATE IN THE DAY ACROSS OAJ AND EWN AS WELL BY LATE IN THE DAY. FEEL SHOWERS WILL BE MORE PREVALENT FRIDAY AFTERNOON. NORTH WINDS...VEERING THE SE BY LATER IN THE DAY FRIDAY. WINDS MAY STRUGGLE TO VEER ACROSS THE INLAND SITES IF THE WEDGE ACROSS CENTRAL NC IS STRONGER THAN FORECAST. LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 300 PM THURSDAY...SUB-VFR CONDITIONS WILL BE POSSIBLE FRIDAY NIGHT WITH INCREASING CLOUDS AND PSBL PATCHY LIGHT RAIN AS WARM FRONT MOVES ACROSS FROM S. WDSPRD SUB-VFR LIKELY SAT AFTN INTO SAT NIGHT WITH SHOWERS AND PSBL ISOLD TSTMS AHEAD OF COLD FRONT. VFR EXPECTED FOR SUN-MON AS DRY HIGH PRESSURE BUILDS IN BEHIND FRONT. BRIEF PERIOD OF SUB-VFR PSBL LATE MON NIGHT AND EARLY TUESDAY AS ANOTHER FRONT MOVES THROUGH. && .MARINE... SHORT TERM /THROUGH FRIDAY/... AS OF 930 PM THU...MADE SOME TWEAKS TO THE WIND GRIDS TO INCORPORATE LATEST RUC AND HIGH RES MESO MODELS WHICH SEEM TO BE DOING A BETTER JOB DEPICTING THE COASTAL TROF...WHICH IS NOW CLEARLY EVIDENT IN OBS ALONG THE OUTER BANKS AND JUST OFF THE SE COAST. WINDS HAVE SHIFTED TO EAST ACROSS THE OUTER BANKS AND ALBEMARLE AND JUST OFF THE SE COAST. WINDS WILL CONTINUE TO VEER TO THE SE BY MORNING. COULD SEE SLIGHTLY HIGHER WINDS ACROSS OUTER PORTIONS OF THE SOUTHERN AND CENTRAL WATERS. SEAS WILL REMAIN AROUND 2-4 FT THROUGH THIS EVENING...THEN BEGINS TO BUILD SOUTH OF HATTERAS LATE TONIGHT AND FRI. SEAS AS HIGH AS 6 FT POSSIBLE ACROSS THE OUTER PORTIONS OF THE SOUTHERN WATERS LATE FRI. LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 300 PM WEDNESDAY...MARINERS CAN EXPECT STRONG SMALL CRAFT ADVISORY CONDITIONS SATURDAY AND SATURDAY NIGHT. THE SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP LATE FRIDAY NIGHT AND ARE FORECAST TO END LATE SUNDAY. A WEAK COASTAL TROF WILL MOVE INLAND AS A WARM FRONT FRIDAY NIGHT...THEN A COLD FRONT WITH A TIGHT PRES GRADIENT WILL MOVE THROUGH SAT INTO EARLY SUNDAY WITH SOUTHERLY WINDS 25 TO 30 KT. HAVE KEPT WINDS BELOW GALES DUE TO COLD SHELF WATERS LIMITING MIXING. HIGH PRESSURE WILL FOLLOW FOR SUNDAY THROUGH MONDAY. SW WINDS WILL INCREASE TO 15-20 KT AHEAD OF NEXT FRONT MON NIGHT AND BECOME W-NW WITH PASSAGE EARLY TUESDAY. A BLEND OF WW3 AND LOCAL NWPS USED FOR SEAS MOST OF PERIOD. HEIGHTS BUIDLING TO 4-6 FT FRI NIGHT...PEAKING 8-12 FT SAT NIGHT. SEAS THEN GRADUALLY SUBSIDING BELOW 6 FT BY SUN EVENING...AND 2-4 FT EARLY MONDAY. HEIGHTS WILL BUILD AGAIN TO 4-5 FT WITH INCREASING WINDS MON NIGHT INTO TUE. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SK NEAR TERM...RSB/SK SHORT TERM...SK LONG TERM...JBM AVIATION...RSB/JBM MARINE...JBM/SK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1032 PM EST THU JAN 9 2014 .SYNOPSIS... A WEAK WARM FRONT OVER THE OHIO VALLEY WILL MOVE ACROSS THE AREA EARLY FRIDAY MORNING. LOW PRESSURE WILL DEVELOP OVER THE PLAINS STATES AND MOVE ACROSS THE GREAT LAKES ON SATURDAY. THE ASSOCIATED COLD FRONT WILL MOVE ACROSS THE AREA ON SATURDAY. A MOIST AND RELATIVELY WARM FLOW WILL MOVE NORTH AHEAD OF THE FRONT. THE AIR BEHIND THE FRONT IS ONLY SLIGHTLY COLDER. HIGH PRESSURE FROM THE SOUTHERN PLAINS WILL BUILD ACROSS THE AREA ON SUNDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... THE LAST GOOD SURGE OF MOISTURE/UPWARD MOTION IS FILLING IN AND NOW CROSSING THE AREA...MOSTLY SOUTH AND EAST OF TOLEDO. THE SNOW SHOULD TAPER OFF FROM WEST TO EAST DURING THE EARLY MORNING HOURS. WILL HAVE TO WATCH TO SEE IF MUCH FREEZING DRIZZLE DEVELOPS. THE SATELLITE LOOP SHOWS THE HIGHER CLOUDS ROTATING NORTHEAST AND WE WILL LOSE THE DEEP MOISTURE DURING THE EARLY MORNING HOURS. THIS WOULD LEAVE JUST THE LOW LEVEL MOISTURE WITH LITTLE POTENTIAL FOR ICE CRYSTAL SEEDING FROM ABOVE AND NO DEEP UPWARD MOTION. THIS WOULD PRODUCE ONLY DRIZZLE. TEMPERATURES WILL BE RISING BUT MOST AREAS WILL REMAIN AT OR BELOW FREEZING THROUGH THE EARLY MORNING HOURS. THE FRESH COATING OF SNOW MIGHT ABSORB ANY FREEZING DRIZZLE BUT IT DOES NOT TAKE MUCH GLAZE TO CAUSE PROBLEMS IN WHICH CASE WE WOULD ISSUE A WINTER WEATHER ADVISORY OR FREEZING RAIN ADVISORY. TEMPERATURES WILL BE STEADY OR SLOWLY RISING. MOST AREAS WILL BE AROUND FREEZING FRIDAY MORNING EXCEPT PROBABLY TOLEDO AND INLAND ERIE AND CRAWFORD COUNTIES PENNSYLVANIA WHICH MAY STILL BE IN THE MID/UPPER 20S. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/... THERE COULD BE A FEW POCKETS OF FREEZING DRIZZLE/RAIN FRIDAY MORNING BUT IT WILL QUICKLY CHANGE OVER TO ALL RAIN BEFORE ENDING. WE WILL THEN AWAIT THE ARRIVAL OF A STRONGER PIECE OF SOUTHERN STREAM JET ENERGY THAT WILL ARRIVE FRIDAY NIGHT INTO SATURDAY. THE STEADIER RAINS WILL BE BETWEEN THE OVERNIGHT HOURS OF FRIDAY NIGHT UNTIL AROUND NOON ON SATURDAY. TEMPERATURES WILL AGAIN BE NON DIURNAL FRIDAY NIGHT WITH TEMPERATURES SLOWLY WARMING. THIS WARMING AND THE RAINFALL WILL CAUSE AREA CREEKS AND STREAMS TO RISE. ANY ICE THAT CAN BREAK AWAY COULD LEAD TO ICE JAM FLOODING. WE WILL EVALUATE THIS POTENTIAL OVER THE NEXT FEW SHIFTS TO DETERMINE IF WE NEED AN AREAL FLOOD WATCH. THE COLD FRONT WILL BE EAST OF THE AREA BY SATURDAY EVENING WITH SOME SNOW SHOWERS POSSIBLE IN ITS WAKE. IT WILL BE A BRIEF PERIOD OF SNOW THAT WILL END ON SUNDAY ACROSS NE OHIO INTO NW PA. && .LONG TERM /MONDAY THROUGH THURSDAY/... ACTIVE STRETCH OF WEATHER IN THE EXTENDED FORECAST WITH ANOTHER TROUGH DIGGING OVER THE EASTERN UNITED STATES BY MID-WEEK. A CLIPPER WILL PASS NORTH OF THE LAKES ON MONDAY WITH THE GFS BEING MORE AGGRESSIVE WITH A COLD PUSH OF AIR BEHIND THE SYSTEM. THE WARMER ECMWF LEAVES WINDS OUT OF THE SOUTHWEST AND FEEL THIS MAY BE THE BETTER SOLUTION IN ADVANCE OF A STRONGER TROUGH DROPPING SOUTH OUT OF CANADA ON TUESDAY. TWEAKED TEMPERATURES UP ON MONDAY NIGHT AND TUESDAY AND RAISED POPS. BY TUESDAY CONFIDENCE IN THE ECMWF DECREASES AS IT TRIES TO TRACK A STRENGTHENING LOW UP THE APPALACHIANS. OUR PROXIMITY TO THE LOW WILL DEPEND ON TIMING OF THE NEXT TROUGH AND COULD END UP BEING FURTHER EAST IF THE UPPER TROUGH RAPIDLY DEEPENS OVER THE GREAT LAKES. A COLD FRONT WILL MOVE ACROSS THE AREA LATE TUESDAY AND ADJUSTED TEMPERATURES DOWN A COUPLE DEGREES ON TUESDAY NIGHT AND WEDNESDAY. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... FIRST ROUND OF SNOW MOVING THROUGH THE NORTHEAST PORTIONS OF THE FORECAST AREA AT THIS TIME AND APPEARS TO BE WEAKENING AS IT MOVES EAST. SECOND ROUND OVER SOUTHWEST OHIO APPEARS TO BE A BIT MORE VIGOROUS. LATEST HRRR MODEL SHOWS THIS BAND WILL STAY TOGETHER AS IT MOVES THROUGH THE REGION. TEMPERATURES WILL BEGIN TO WARM AND WE COULD SEE SOME FREEZING DRIZZLE LATE TONIGHT AND THEN CHANGE OVER TO ALL DRIZZLE. LOW CEILINGS AND VISIBILITIES WILL PREVAIL THROUGH THE DAY TOMORROW. WINDS SHOULD BE LIGHT SOUTH TO SOUTHEAST THROUGH THE DAY. OUTLOOK...NON VFR RETURNING LATE FRIDAY NIGHT/SATURDAY. LIMITED NON VFR SATURDAY NIGHT THROUGH TUESDAY. && .MARINE... HIGH PRESSURE OVER THE LAKE WILL SHIFT OFF THE EAST COAST TONIGHT WITH SOUTHERLY WINDS DEVELOPING. WINDS WILL INCREASE TO 20 TO 30 KNOTS ON SATURDAY AS LOW PRESSURE TRACKS ACROSS THE WESTERN LAKES AND PULLS A COLD FRONT ACROSS THE AREA. A RIDGE WILL BUILD OVER THE LAKE ON SATURDAY NIGHT WITH WINDS SHIFTING TO WESTERLY THEN BACKING TO SOUTHERLY AGAIN ON SUNDAY. WEAK LOW PRESSURE WILL PASS NORTH OF THE LAKE ON MONDAY FOLLOWED BY A STRONGER LOW PRESSURE SYSTEM PULLING A COLD FRONT ACROSS THE LAKE ON TUESDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...KOSARIK NEAR TERM...KOSARIK SHORT TERM...MULLEN LONG TERM...KEC AVIATION...LOMBARDY MARINE...KEC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
659 PM EST THU JAN 9 2014 .SYNOPSIS... A WARM FRONT WILL MOVE ACROSS THE AREA TONIGHT INTO FRIDAY WITH A COLD FRONT CROSSING THE REGION ON SATURDAY. A RIDGE WILL MOVE ACROSS THE REGION ON SUNDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... FOR THE EARLY EVENING UPDATE...MADE MINOR ADJUSTMENTS TO THE POP UPWARDS AS THE SNOW SPREADS NORTH AND EAST. MOST EVERYONE SHOULD SEE A COUPLE OF WAVES OF LIGHT TO MODERATE SNOW. CHANGED THE MENTION OF FREEZING RAIN TO FREEZING DRIZZLE. THE SATELLITE LOOP SHOWS THE HIGHER CLOUDS ROTATING NORTHEAST AND WE SHOULD LOSE THE DEEP MOISTURE LATE TONIGHT/EARLY FRIDAY MORNING. THIS WOULD LEAVE JUST THE LOW LEVEL MOISTURE AND LITTLE POTENTIAL FOR ICE CRYSTAL SEEDING FROM ABOVE OR DEEP UPWARD MOTION WHICH WOULD PRODUCE ONLY DRIZZLE. TEMPERATURES WILL BE RISING SO IT WILL BE CLOSE AS FAR AS ABOVE/BELOW FREEZING EXCEPT ACROSS FAR NORTHWEST OHIO WHERE IT WILL STILL CLEARLY BE COLD ENOUGH. WITH A FRESH COAT OF SLUSH/SNOW ON THE ROADS IT MIGHT ABSORB THE FREEZING DRIZZLE IN MOST AREAS. EARLIER DISCUSSION... A WARM FRONT WILL LIFT INTO THE AREA TONIGHT. SNOW WILL CONTINUE TO SPREAD ACROSS THE REGION THROUGH THE NIGHT BUT IT APPEARS IT COULD COME WITH A COUPLE OF WAVES. ONE THIS EVENING AND THE OTHER DURING THE OVERNIGHT HOURS. SNOWFALL AMOUNTS COULD BE IN THE ONE TO TWO INCH RANGE BY SUNRISE. THE HIGHER AMOUNTS WILL LIKELY BE ACROSS THE SOUTHEASTERN COUNTY WARNING AREA. WE CANT COMPLETELY RULE OUT A VERY BRIEF PERIOD OF FREEZING DRIZZLE/RAIN IN THE COLDER LOCATIONS BUT BELIEVE THE CHANCE IS LOW. WE DO HAVE IT MENTIONED IN THE LOCATIONS THAT SHOULD BE COOLER. TEMPERATURES WILL LIKELY DIP BRIEFLY THIS EVENING THEN SLOWLY WARM THROUGH THE OVERNIGHT HOURS. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY NIGHT/... THERE COULD BE A FEW POCKETS OF FREEZING DRIZZLE/RAIN FRIDAY MORNING BUT IT WILL QUICKLY CHANGE OVER TO ALL RAIN BEFORE ENDING. WE WILL THEN AWAIT THE ARRIVAL OF A STRONGER PIECE OF SOUTHERN STREAM JET ENERGY THAT WILL ARRIVE FRIDAY NIGHT INTO SATURDAY. THE STEADIER RAINS WILL BE BETWEEN THE OVERNIGHT HOURS OF FRIDAY NIGHT UNTIL AROUND NOON ON SATURDAY. TEMPERATURES WILL AGAIN BE NON DIURNAL FRIDAY NIGHT WITH TEMPERATURES SLOWLY WARMING. THIS WARMING AND THE RAINFALL WILL CAUSE AREA CREEKS AND STREAMS TO RISE. ANY ICE THAT CAN BREAK AWAY COULD LEAD TO ICE JAM FLOODING. WE WILL EVALUATE THIS POTENTIAL OVER THE NEXT FEW SHIFTS TO DETERMINE IF WE NEED AN AREAL FLOOD WATCH. THE COLD FRONT WILL BE EAST OF THE AREA BY SATURDAY EVENING WITH SOME SNOW SHOWERS POSSIBLE IN ITS WAKE. IT WILL BE A BRIEF PERIOD OF SNOW THAT WILL END ON SUNDAY ACROSS NE OHIO INTO NW PA. && .LONG TERM /MONDAY THROUGH THURSDAY/... ACTIVE STRETCH OF WEATHER IN THE EXTENDED FORECAST WITH ANOTHER TROUGH DIGGING OVER THE EASTERN UNITED STATES BY MID-WEEK. A CLIPPER WILL PASS NORTH OF THE LAKES ON MONDAY WITH THE GFS BEING MORE AGGRESSIVE WITH A COLD PUSH OF AIR BEHIND THE SYSTEM. THE WARMER ECMWF LEAVES WINDS OUT OF THE SOUTHWEST AND FEEL THIS MAY BE THE BETTER SOLUTION IN ADVANCE OF A STRONGER TROUGH DROPPING SOUTH OUT OF CANADA ON TUESDAY. TWEAKED TEMPERATURES UP ON MONDAY NIGHT AND TUESDAY AND RAISED POPS. BY TUESDAY CONFIDENCE IN THE ECMWF DECREASES AS IT TRIES TO TRACK A STRENGTHENING LOW UP THE APPALACHIANS. OUR PROXIMITY TO THE LOW WILL DEPEND ON TIMING OF THE NEXT TROUGH AND COULD END UP BEING FURTHER EAST IF THE UPPER TROUGH RAPIDLY DEEPENS OVER THE GREAT LAKES. A COLD FRONT WILL MOVE ACROSS THE AREA LATE TUESDAY AND ADJUSTED TEMPERATURES DOWN A COUPLE DEGREES ON TUESDAY NIGHT AND WEDNESDAY. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... FIRST ROUND OF SNOW MOVING THROUGH THE NORTHEAST PORTIONS OF THE FORECAST AREA AT THIS TIME AND APPEARS TO BE WEAKENING AS IT MOVES EAST. SECOND ROUND OVER SOUTHWEST OHIO APPEARS TO BE A BIT MORE VIGOROUS. LATEST HRRR MODEL SHOWS THIS BAND WILL STAY TOGETHER AS IT MOVES THROUGH THE REGION. TEMPERATURES WILL BEGIN TO WARM AND WE COULD SEE SOME FREEZING DRIZZLE LATE TONIGHT AND THEN CHANGE OVER TO ALL DRIZZLE. LOW CEILINGS AND VISIBILITIES WILL PREVAIL THROUGH THE DAY TOMORROW. WINDS SHOULD BE LIGHT SOUTH TO SOUTHEAST THROUGH THE DAY. OUTLOOK...NON VFR RETURNING LATE FRIDAY NIGHT/SATURDAY. LIMITED NON VFR SATURDAY NIGHT THROUGH TUESDAY. && .MARINE... HIGH PRESSURE OVER THE LAKE WILL SHIFT OFF THE EAST COAST TONIGHT WITH SOUTHERLY WINDS DEVELOPING. WINDS WILL INCREASE TO 20 TO 30 KNOTS ON SATURDAY AS LOW PRESSURE TRACKS ACROSS THE WESTERN LAKES AND PULLS A COLD FRONT ACROSS THE AREA. A RIDGE WILL BUILD OVER THE LAKE ON SATURDAY NIGHT WITH WINDS SHIFTING TO WESTERLY THEN BACKING TO SOUTHERLY AGAIN ON SUNDAY. WEAK LOW PRESSURE WILL PASS NORTH OF THE LAKE ON MONDAY FOLLOWED BY A STRONGER LOW PRESSURE SYSTEM PULLING A COLD FRONT ACROSS THE LAKE ON TUESDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...NONE. PA...NONE. MARINE...NONE. && $$ SYNOPSIS...MULLEN NEAR TERM...KOSARIK SHORT TERM...MULLEN LONG TERM...KEC AVIATION...LOMBARDY MARINE...KEC
AREA FORECAST DISCUSSION
NWS TULSA OK
915 PM CST THU JAN 9 2014 ...UPDATE... .DISCUSSION... A LOW CLOUD DECK WITH PATCHY AREAS OF REDUCED VIS CONTINUED ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS EVENING. THESE CONDITIONS HAVE KEPT TEMPS FROM CHANGING MUCH THROUGH THE EVENING HOURS...AND IN SOME PLACES...THE TEMP HAS COME UP A DEGREE OR SO. TEMPERATURES WILL CONTINUE TO HOVER CLOSE TO CURRENT READINGS INTO THE OVERNIGHT HOURS AND BEGIN SLOWLY WARMING DURING THE EARLY MORNING HOURS AS AN UPPER LEVEL SHORTWAVE AND ASSOCIATED COLD FRONT APPROACH THE REGION. THUS...LOW TEMPS TONIGHT WILL MORE THAN LIKELY BE REALIZED OVER THE NEXT FEW HOURS FOR MOST LOCATIONS. RAIN CHANCES WILL INCREASE LATE TONIGHT INTO FRIDAY FROM SOUTH TO NORTH WITH ALSO ISOLATED CHANCES FOR THUNDER AS THE WAVE APPROACHES. LATEST LOCAL MODEL AND HRRR HAVE BACKED OFF ON THE TIMING OF PRECIP SPREADING ACROSS THE REGION TONIGHT. THUS...HAVE BACKED OFF ON POPS SOME THROUGH 12Z FOR THE EVENING UPDATE... OTHERWISE THE REST OF THE CURRENT FORECAST FOR TONIGHT SEEMS TO BE HANDLING WELL. && .PRELIMINARY POINT TEMPS/POPS... TUL 35 54 32 55 / 40 80 10 0 FSM 34 57 33 55 / 40 100 30 0 MLC 39 60 35 60 / 50 90 10 0 BVO 35 51 30 56 / 30 60 10 0 FYV 35 54 29 51 / 30 100 20 0 BYV 34 53 31 50 / 30 100 30 0 MKO 34 56 31 56 / 50 90 10 0 MIO 36 49 29 51 / 30 80 10 0 F10 35 58 34 58 / 50 80 10 0 HHW 36 63 36 61 / 60 100 30 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...20 AVIATION.....14
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
925 PM CST THU JAN 9 2014 .UPDATE... VISIBILITIES HAD DROPPED TO A LESS THAN 1 MILE NORTH OF JONESBORO THIS EVENING. THIS AREA WAS NORTH OF A WEAK SURFACE WARM FRONT THAT EXTENDED ROUGHLY ALONG INTERSTATE 40. HRRR AND GFS LAMP GUIDANCE SUGGEST WARM ADVECTION OVER THE NEARLY STATIONARY FRONT WILL DROP VISIBILITIES LOWER DURING THE OVERNIGHT. WITH TEMPS NEAR FREEZING...WILL NEED TO MONITOR TEMPS CLOSELY INTO THE EARLY OVERNIGHT. THEREAFTER...00Z NAM DEPICTS WARMING SURFACE TEMPS WITH WARM FRONT LIFTING THROUGH. HRRR DEPICTS ADDITIONAL AREAS OF FOG FORMING IN THE CLEAR SLOT OVER CENTRAL MS... AND SPREADING NORTH OVERNIGHT. FOR THE 9 PM UPDATE... HAVE KEPT THE MENTION OF DENSE FOG WEST OF THE MS RIVER... BUT DENSE FOG CANNOT BE RULED OUT EAST OF THE MS RIVER TOWARD MORNING...ASSOCIATED WITH A MARINE WARM FRONT LIFTING NORTH. PWB && .PREV DISCUSSION... /ISSUED 656 PM CST THU JAN 9 2014/ UPDATE... UPDATED FOR THE 00Z AVIATION DISCUSSION. PREV DISCUSSION... /ISSUED 339 PM CST THU JAN 9 2014/ DISCUSSION... NEAR NORMAL TO SLIGHTLY ABOVE NORMAL TEMPERATURES EXPECTED OVER MUCH OF THE NEXT SEVEN DAYS. THE SHORTWAVE THAT HAS CAUSED THE WINTRY MIX AND RAIN TODAY IS PUSHING OUT OF THE MIDSOUTH. HOWEVER EXPECT SMALL CHANCES OF RAIN WILL CONTINUE TONIGHT INTO FRIDAY AS WARM AIR ADVECTION MAY PRODUCE SOME LIGHT SHOWERS ACROSS THE AREA. LOWS WILL ACTUALLY OCCUR THIS EVENING DUE TO THE WARM AIR ADVECTION TONIGHT. TEMPERATURES WILL SLOWLY RISE OVERNIGHT. THIS MEANS LOWS WILL BE AT OR ABOVE FREEZING TONIGHT WITH READINGS RANGING FROM THE LOWER 30S TO AROUND 40 DEGREES. HIGHS ON FRIDAY WILL BE IN THE 50S AND WILL FEEL GREAT AFTER THE EXTREME COLD THAT THE MIDSOUTH HAS EXPERIENCED. A COLD FRONT WILL MOVE THROUGH THE MIDSOUTH FRIDAY NIGHT. BETTER CHANCES FOR SHOWERS WILL OCCUR AS A RESULT. ALSO...CAN/T RULE OUT A FEW THUNDERSTORMS OCCURRING ACROSS NORTH MISSISSIPPI. DO NOT REALLY EXPECT MUCH IF ANY COOL DOWN AT ALL BEHIND THE FRONT AS IT IS MORE OF A PACIFIC ORIGIN FRONT THAN AN ARCTIC FRONT. HIGH PRESSURE WILL SETTLE OVER THE REGION FOR THE WEEKEND. A NICE WARMING TREND IS EXPECTED ON SUNDAY AS THE HIGH SHIFTS EAST AND WINDS TURN AROUND TO THE SOUTH. AS A RESULT...HIGHS WILL GET INTO THE LOWER TO MID 60S IN MANY LOCATIONS. A COLD FRONT WILL MOVE THROUGH SUNDAY NIGHT. THE GFS HAS LITTLE PRECIPITATION WITH THE FRONT WHILE THE ECMWF DEVELOPS A SFC LOW ALONG THE FRONT. AS A RESULT...THE MODEL PRODUCES QUITE A BIT OF QPF ACROSS THE AREA WITH BEST CHANCES OCCURRING ACROSS NORTHEAST MISSISSIPPI. HAVE TRIED TO GO WITH AN IN BETWEEN SOLUTION FOR NOW. HIGH PRESSURE WILL RETURN ON MONDAY AND MONDAY NIGHT. HOWEVER A REINFORCING FRONT WILL MOVE THROUGH ON TUESDAY AND WILL BRING COLDER AIR INTO THE AREA. HOW COLD THE AIR WILL BE DEPENDS ON WHICH MODEL YOU LOOK AT. THE ECMWF IS MUCH COLDER THAN THE GFS. AGAIN HAVE TRIED TO IN BETWEEN FOR TEMPERATURES FROM TUESDAY AND BEYOND AS RESULT OF THE DIFFERENT SOLUTIONS. HIGH PRESSURE WILL RETURN TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. ANOTHER COLD FRONT WILL APPROACH ON THURSDAY. KRM && .AVIATION... 00Z TAF CYCLE LARGE SPREAD IN CIGS THIS EVENING WITH KJBR ALREADY LIFR TO MVFR AT KMEM TO VFR AT BOTH KMKL AND KTUP. CIGS AND VSBYS SHOULD SLOWLY LOWER LATER THIS EVENING AT ALL SITES WITH LOW LEVEL STRATUS AND FOG EXPECTED ESPECIALLY LATE TONIGHT INTO EARLY FRIDAY MORNING AT ALL SITES. THE QUESTION REMAINS HOW LOW...WITH AT LEAST IFR CIGS ANTICIPATED AT KMEM...KMKL...AND KTUP...AND LOWER AT KJBR WHERE VLIFR CANNOT BE RULED OUT. LIFR CIGS ARE A POTENTIAL EVEN AT THE OTHER SITES LATE TONIGHT AND AMENDMENTS MAY BECOME REQUIRED. THIS WILL BE CLOSELY MONITORED THROUGH THE EVENING. ALSO FOG MAY BECOME DENSE AT KJBR LATE TONIGHT AS WELL. CIGS SHOULD SLOWLY RISE WITH THE PASSAGE OF A WARM FRONT FRIDAY MORNING AT KMEM...KTUP...AND KMKL...BEFORE LOWERING AGAIN TOWARDS THE END OF THE PERIOD WITH THE APPROACH OF THE NEXT SHORTWAVE. FURTHER NORTH AT KJBR...CIGS AND VSBYS WILL STRUGGLE TO RISE AND SHOULD REMAIN QUITE LOW THROUGH THE TAF PERIOD. A PERIOD OF SHOWERS IS POSSIBLE WITH THE WARM FRONT IN THE MORNING AT KMEM...KTUP...AND KMKL. THERE SHOULD THEN BE A BREAK FOR A FEW HOURS BEFORE MORE RAIN DEVELOPS TOWARDS THE END OF THE PERIOD WITH APPROACHING SHORTWAVE FROM THE WEST. AT KJBR...RAIN CHANCES SHOULD CONTINUE THROUGH MUCH OF FRIDAY DUE TO CLOSE PROXIMITY OF THE FRONT AND EVENTUAL INFLUENCE FROM UPPER WAVE AS WELL BY AFTERNOON. WINDS SHOULD EVENTUALLY GO SOUTHERLY EVERYWHERE ON FRIDAY AND INCREASE IN SPEEDS WITH APPROACH OF WESTERN DISTURBANCE ALOFT. COULD ALSO BE SOME COMPRESSIONAL ISSUES LATE IN THE PERIOD AS LOW LEVEL JET STRENGTHENS LATE FRIDAY AFTERNOON FROM THE SOUTH. JLH && .MEG WATCHES/WARNINGS/ADVISORIES... AR...DENSE FOG ADVISORY UNTIL 8 AM CST FRIDAY FOR CLAY-CRAIGHEAD- CRITTENDEN-CROSS-GREENE-LAWRENCE-MISSISSIPPI-POINSETT- RANDOLPH-ST. FRANCIS. MO...DENSE FOG ADVISORY UNTIL 8 AM CST FRIDAY FOR DUNKLIN-PEMISCOT. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1028 PM CST TUE JAN 7 2014 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .UPDATE... ISSUED AT 822 PM CST TUE JAN 7 2014 NOW THAT THE CORE OF THE COLD IS OFF TO OUR E...TEMPS WL BE DRIVEN BY MORE THAN JUST ADVECTION. SML LEAF-LIKE PATCH OF HIGH AC COMING ACRS THE SRN PART OF THE FCST AREA AS HOLDING TEMPS UP. THAT SHOULD EXIT THE SE PART OF THE AREA ARND MIDNIGHT. ADJUSTED HOURLY TEMP GRIDS TO ACCOUNT FOR THE FEATURE. IT MAY BE HOLDING TEMPS UP NOW...BUT SHOULD DEPART IN TIME TO NOT HAVE A SIG IMPACT ON MINS. WHERE SKIES WERE CLEAR...DECRG SFC PRESSURE GRADIENT HAS ALLOWED WINDS TO DIE OFF IN THE TYPICAL COLDS SPOTS IN NRN WI...AND TEMPS HAVE TANKED. LNL ALREADY DOWN AS LOW AS 26 BELOW. EXPECT SITES LIKE D25/RHI/TKV/RRL/EGV TO FOLLOW DURING THE NIGHT. TWEAKED MINS DOWN SOME IN THESE AREAS. WINDS WERE GENERALLY MARGINAL FOR A WIND CHILL ADVISORY. THOSE SITES THAT STILL HAD WIND WERE MOSTLY NOT MEETING CRITERIA. BUT TEMPS WL BE FALLING TO VERY COLD READINGS...AND DON/T THINK MOST SITES WL BE CALM ALL NGT. WITH MIN WIND SPEED CRITERIA FOR A WIND CHILL HEADLINE NOW ONLY 4 MPH...THERE WL CERTAINLY BE TIMES WHEN CRITERIA ARE MET ACRS ALMOST THE ENTIRE AREA BY MORNING. AND THE FEW SPOTS THAT STAY CALM MAY WELL BE APPROACHING 30 BELOW AIR TEMPERATURES. SO...WL LEAVE THE ADVISORY INTACT. UPDATED GRIDS AND DERIVED ZONES/AFM/PFM ALREADY OUT. UPDATED WSW AND HWO TO FOLLOW SHORTLY. && .SHORT TERM...TONIGHT AND WEDNESDAY ISSUED AT 240 PM CST TUE JAN 7 2014 THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH PRESSURE CENTERED OVER THE GULF COAST...AND A RIDGE AXIS EXTENDING NORTHEAST ACROSS THE PLAINS TO CENTRAL CANADA. AREAS OF LOW CLOUD COVER CONTINUE TO FLOW SOUTHEAST AHEAD OF THE RIDGE AXIS FROM SOUTHERN CANADA AND NORTHERN MINNESOTA AND INTO WISCONSIN...BUT THE LATEST SATELLITE IMAGES SHOW THE STRATUS DISSIPATING AS IT MOVES INTO NORTH-CENTRAL WISCONSIN. WITH PARTLY TO MOSTLY SUNNY CONDITIONS...TEMPERATURES AND WIND CHILLS HAVE WARMED INTO THE SINGLE DIGITS BELOW ZERO AND BETWEEN 20 TO 30 DEGREES BELOW ZERO RESPECTIVELY. AS HIGH PRESSURE SHIFTS EAST INTO THE REGION OVER THE NEXT 24 HOURS...TEMPS AND WIND CHILLS REMAIN THE MAIN FORECAST CONCERNS...FOLLOWED BY CLOUDS. TONIGHT...THE SURFACE RIDGE AXIS OVER THE NORTHERN MISSISSIPPI VALLEY AND NORTHERN PLAINS WILL MOVE EAST TOWARDS THE STATE. AREAS OF LOW STRATUS UPSTREAM WILL CONTINUE TO FLOW SOUTHEAST AHEAD OF THE SURFACE HIGH WHICH MAKES CLOUD FORECAST PROBLEMATIC. DO NOT THINK MODELS HAVE A GOOD HANDLE ON THIS CLOUD COVER...BUT DO INDICATE DIMINISHING LOW LEVEL RH THAT WOULD POINT TOWARDS THIS CLOUD COVER BREAKING UP. SO GENERALLY WENT WITH MOSTLY CLEAR TO PARTLY CLOUDY CONDITIONS FOR THE EVENING...WITH A LITTLE HIGHER CLOUD COVER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN...THEN SKY CONDITIONS TURNING MOSTLY CLEAR EVERYWHERE OVERNIGHT. DUE TO THE INCOMING SURFACE HIGH...WINDS WILL BE SUBSIDING TONIGHT...AND SOME POTENTIAL FOR DECOUPLING OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. LOW LEVEL WINDS WILL BE RIGHT ON THE CUSP...AND IF THIS OCCURS...LOW TEMPS WILL BE SEVERAL DEGREES COLDER THAN IN THE GOING FORECAST. AS A RESULT...DID SIDE WITH THE COLDER GUIDANCE BUT DID NOT GO WITH THE COLDEST SOLUTIONS IN CASE DECOUPLING DID NOT OCCUR. THIS WOULD PLACE LOW TEMPS MAINLY BETWEEN 10 AND 20 BELOW...WITH A FEW COLDER SPOTS OVER N-C WISCONSIN...AND A FEW WARMER SPOTS NEAR THE LAKE SHORE. WIND CHILLS WILL FALL TO 25 T0 35 DEGREES BELOW ZERO. WIND CHILL ADVISORY HEADLINES WILL GO ON AS PLANNED...WITH THE CAVEAT THAT SOME LOCATIONS MAY SEE A CALM WIND FOR A PERIOD LATE TONIGHT. WEDNESDAY...HIGH PRESSURE WILL MOVE OVER THE AREA. TEMPERATURES WILL CONTINUE THEIR SLOW MODERATION...AND WITH PLENTY OF SUNSHINE...READINGS WILL RETURN TO THE SINGLE DIGITS ABOVE ZERO. APPARENT TEMPS WILL RISE ABOVE ADVISORY CRITERIA BY LATE IN THE MORNING...SO WILL RUN HEADLINES THROUGH 18Z. .LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY ISSUED AT 240 PM CST TUE JAN 7 2014 ARCTIC AIR MASS WITH SUB ZERO LOW TEMPERATURES WILL LINGER WEDNESDAY NIGHT DUE TO ANTICIPATED CLEAR SKIES AND CALM WINDS UNDER THE SURFACE HIGH PRESSURE SYSTEM. ATTENTION THEN TURNS TO PCPN POTENTIAL LATE IN THE WEEK WITH THE WAA FLOW. INITIAL WEAK SHORT WAVE PASSES JUST SOUTH OF THE AREA THURSDAY INTO THURSDAY NIGHT. CONSIDERED ADDING A SLIGHT CHANCE OF PCPN BUT UNSURE OF SATURATION FOR NOW. LATER SHIFTS CAN SOME ZL- THURSDAY NIGHT IF WARRANTED. MAIN SHORTWAVE TO PASS OVER LATER FRIDAY INTO FRIDAY EVENING WITH PROGS INDICATED UP TO 0.25 WATER EQUIVALENT BY FRIDAY MIDNIGHT OVER THE SOUTHEAST HALF OF THE FORECAST AREA. FORECAST SOUNDINGS SUGGESTING A MIX OF ZR/S OVER MOST LOCATIONS AND THEREFORE HAS THE POTENTIAL OF A HEADLINE FOR MIXED PCPN LATE THIS WEEK. HWO ALREADY HIGHLIGHTING THIS CONCERN. SURFACE RIDGE UNDER THE ZONAL FLOW REGIME TO END PCPN SATURDAY MORNING WITH WAA PATTERN STARTING UP AGAIN SATURDAY NIGHT INTO SUNDAY. THE FIRST IN A SERIES OF LOW PRESSURE SYSTEMS IS PROGGED TO TRACK NORTH OF LAKE SUPERIOR LATE NEXT WEEKEND WILL DRAG A COOL FRONT OVER THE AREA LATER SUNDAY INTO SUNDAY NIGHT...FOLLOWED WITH ANOTHER CLIPPER SYSTEM NORTH OF THE REGION TOWARD TUESDAY. WILL CONTINUE LOW END CHANCES OF PCPN WITH THE VARIOUS FROPAS. FOR WHAT ITS WORTH...END PERIODS OF THE MEDIUM RANGE MODELS ARE INDICATING SOME COLDER AIR TO WORK TOWARD THE GREAT LAKES REGION LATE NEXT WEEKEND. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1025 PM CST TUE JAN 7 2014 GENERALLY GOOD FLIGHT CONDITIONS EXPECTED AS ARCTIC AIR DOMINATES THE AREA. SC THAT WAS ACRS MN HAS MADE LITTLE PROGRESS TO THE SE...BUT SOME SC HAS DRIFTED INTO THE FAR N FROM LAKE SUPERIOR. THAT COULD BRUSH THROUGH RHI FOR A TIME...BUT THINK THE MVFR CIGS WOULD BE BRIEF. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL NOON CST WEDNESDAY FOR WIZ005-010>013- 018>022-030-031-035>040-045-048>050-073-074. && $$ UPDATE.........SKOWRONSKI SHORT TERM.....MPC LONG TERM......TDH AVIATION.......SKOWRONSKI
AREA FORECAST DISCUSSION
NWS MIAMI FL
304 AM EST FRI JAN 10 2014 .AVIATION... HEAVY RAINFALL CONTINUES TO IMPACT THE COASTAL AND METRO AREAS OF PALM BEACH COUNTY THIS MORNING. THE HRRR MODEL REFLECTIVITIES INITIALIZE WELL WITH THIS ACTIVITY AND INDICATE IT CONTINUING THROUGH DAYBREAK BEFORE DIMINISHING. AS A RESULT...WILL KEEP THE TEMPO IN THE PBI TAF THROUGH 12Z DUE TO VSBYS/CIGS/WX. ELSEWHERE...VFR CONDITIONS WILL PERSIST THROUGH THE MUCH OF THE PERIOD WITH LIGHT SOUTHEAST FLOW CONTINUING. && .PREV DISCUSSION... /ISSUED 643 PM EST THU JAN 9 2014/ AVIATION... THE WARM FRONT THAT HAS BEEN PRODUCING SCATTERED SHOWERS THROUGHOUT THE DAY WILL CONTINUE TO MOVE NORTHWARD THROUGH TONIGHT. LEFT VCSH IN ACROSS ALL TERMINALS THROUGH FRIDAY MORNING, HOWEVER, MOST OF THE SHOWER ACTIVITY WILL REMAIN ACROSS NORTHERN AREAS THIS EVENING ESPECIALLY NEAR KPBI. PATCHY FOG MAY DEVELOP LATE TONIGHT INTO EARLY FRIDAY MORNING AT KAPF AS ENOUGH LOW LEVEL MOISTURE WILL REMAIN IN PLACE. WINDS WILL CONTINUE TO DIMINISH AS THE EVENING PROGRESSES. THE WARM FRONT WILL CONTINUE TO MOVE NORTH ON FRIDAY AND WINDS WILL REMAIN OUT OF THE SOUTHEAST ACROSS ALL TERMINALS. PREV DISCUSSION... /ISSUED 246 PM EST THU JAN 9 2014/ SYNOPSIS... RAIN CHANCES GRADUALLY DECLINE FOR THE REST OF THE WEEK...WITH VERY WARM CONDITIONS PREVAILING. A WEAK COLD FRONT WILL MOVE THROUGH SATURDAY NIGHT. SHORT TERM /TONIGHT THROUGH SUNDAY/... ISENTROPIC LIFT AND MODEST CONVERGENCE CONTINUE TO INTERACT WITH ABUNDANT DEEP-LAYER MOISTURE TO PRODUCE NUMEROUS SHOWERS ACROSS MUCH OF SOUTH FLORIDA. OVERCAST CONDITIONS HAVE LIMITED INSTABILITY THUS FAR...BUT CANT RULE OUT SOME BREAKS IN CLOUDS LATE THIS AFTERNOON...SO WILL KEEP ISOLATED THUNDER IN GRIDS NEAR EAST COAST AND ATLANTIC WATERS. THE CLOUDINESS HAS SUPPRESSED WARMING SOMEWHAT...KEEPING MAXIMA IN 70S MOST AREAS. DEEPEST MOISTURE AXIS WILL INCH NORTHWARD OVERNIGHT...FOCUSING OVER CENTRAL FLORIDA BY FRIDAY. THIS SHOULD LEAD TO A DECLINE IN SHOWER COVERAGE...BUT VERY MOIST AND WARM AIRMASS WILL STILL SUPPORT SCATTERED SHOWERS THROUGH FRIDAY. AS HIGH PRESSURE NEAR THE NORTHEAST CONUS COAST DRIFTS EASTWARD...LOW-LEVEL FLOW OVER SOUTH FLORIDA WILL TRANSITION FROM EASTERLY TO SOUTHEASTERLY...AND DIMINISH SLIGHTLY OVER TIME. FAVORING FOG FORMATION TONIGHT ARE NEAR-SATURATED BOUNDARY LAYER...CALM WINDS...AND SLIGHT MOISTURE ADVECTION FROM THE SOUTHEAST. INHIBITING FOG WILL BE NEAR-OVERCAST CONDITIONS AND SCATTERED SHOWERS. THESE CONFLICTING FACTORS MAKES FOG FORECAST DIFFICULT. HAVE ELECTED TO KEEP PATCHY FOG IN GRIDS MOST INLAND AND WEST COAST AREAS LATE TONIGHT. TEMPERATURES THROUGH SATURDAY WILL BE WELL ABOVE NORMAL...WITH MINIMA IN THE 60S TO LOW 70S. WITH SLIGHTLY MORE SUNSHINE EXPECTED...MAXIMA SHOULD REACH LOW 80S MOST AREAS. WINDS SATURDAY WILL INCREASE OUT OF THE SOUTH IN ADVANCE OF A MID- LATITUDE SHORTWAVE TROUGH AND ATTENDANT COLD FRONT. THE COLD FRONT WILL APPROACH LATE SATURDAY AND CROSS SATURDAY NIGHT. BETTER DYNAMICS WILL RESIDE WELL NORTH OF THE AREA...BUT DIURNAL CONVECTION COULD DEVELOP ALONG THE FRONT OVER CENTRAL FLORIDA. RIGHT NOW...TIMING OF FROPA LOOKS TO BE LATE ENOUGH OVER CENTRAL FLORIDA SUCH THAT WEAK INSTABILITY WILL PRECLUDE MUCH IN THE WAY OF THUNDER. LITTLE/NO COOL AIR IS EXPECTED BEHIND THIS FRONT FOR SUNDAY. LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... LONG RANGE MODELS ARE STILL SHOWING ANOTHER COLD FRONT MOVING THROUGH SOUTH FLORIDA EARLY NEXT WEEK WITH HIGH PRESSURE BUILDING INTO THE AREA FOR MIDDLE TO END OF NEXT WEEK. THIS FRONT WILL BRING DRIER AND COOLER WEATHER TO SOUTH FLORIDA FOR THE MIDDLE TO END OF NEXT WEEK. TEMPERATURES SHOULD REMAIN NEAR NORMAL FOR THIS TIME OF YEAR WITH HIGHS IN THE 70S AND LOWS IN THE 40S EXCEPT 50S OVER THE EAST COAST METRO AREAS. AVIATION... PREVAILING MVFR CONDITIONS ARE EXPECTED FOR THE EAST COAST TAF SITES THROUGH THE AFTERNOON HOURS. BRIEF IFR CONDITIONS ARE POSSIBLE IN SHOWERS. A CONVERGENT LINE OF MODERATE SHOWERS DEVELOPED ACROSS SOUTHERN BROWARD COUNTY EARLY THIS AFTERNOON...AND THIS WILL CONTINUE TO SLOWLY DRIFT NORTH. BY 19Z IT SHOULD MOVE NORTH OF KFLL AND MOVE TO KFXE. ELSEWHERE FOR THE EAST COAST TAF SITES...SCATTERED SHOWERS WILL CONTINUE TO MOVE INTO THE COAST. SHALLOW RAIN SHOWERS APPEAR TO HAVE MOVED INTO KAPF...AND IFR CONDITIONS WERE OCCURRING. THESE SHOWERS WERE NOT SHOWING UP ON THE RADAR. A SHORTWAVE WAS NOTED IN THE VISIBLE IMAGERY JUST TO THE WEST OF NAPLES...AND THIS IS LIKELY RESPONSIBLE FOR THE LOWER CIGS AND RAINFALL. THE WARM FRONT WAS LOCATED ACROSS SOUTH FLORIDA NEAR THE BROWARD /MIAMI- DADE LINE...AND THIS BOUNDARY WILL SLOWLY SLIDE NORTH THROUGH THE DAY TODAY. SHOWERS MAY CONTINUE AT KAPF AND KPBI FOR MUCH OF THE NIGHT...AND KEPT VCSH ELSEWHERE. EASTERLY WINDS 10-15 KNOTS WILL CONTINUE...AND ARE EXPECTED TO DIMINISH THIS EVENING...ESPECIALLY SOUTH. THE BOUNDARY WILL CONTINUE TO MOVE NORTH ON FRIDAY...AND WINDS WILL SHIFT TO THE SOUTHEAST. ONLY ISOLATED SHOWERS ARE IN THE FORECAST...SO DID NOT MENTION IN THE TAFS ON FRIDAY AT THIS TIME. MARINE... WINDS OFF PALM BEACH COUNTY HAVE REMAINED AROUND 20 KNOTS THIS AFTERNOON...SO HAVE EXTENDED ADVISORY UNTIL 0Z. ELSEWHERE...15-20 KNOT EAST WINDS WARRANT SMALL CRAFT TO EXERCISE CAUTION. WINDS SHOULD TURN SOUTHEAST OVERNIGHT THEN TURN SOUTHERLY ON FRIDAY AT SPEEDS OF 10-15 KTS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 81 72 83 68 / 30 20 30 20 FORT LAUDERDALE 81 74 82 71 / 30 20 30 20 MIAMI 83 73 84 71 / 30 20 20 10 NAPLES 82 67 82 68 / 30 20 30 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...54/BNB AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
332 AM CST FRI JAN 10 2014 .DISCUSSION... 816 PM CST RADAR MOSAIC SHOWS CONTINUED LIGHT SNOW ACROSS MUCH OF THE EASTERN CWA FROM NEAR PONTIAC NORTHEAST TO THE NORTHERN CHICAGO METRO. WARM ASCENT CONTINUES ABOVE WITH ADDITIONAL ASCENT LOOKING TO BE PROVIDED BY AN ELONGATED AREA OF CYCLONIC VORTICITY TRAILING A SHORTWAVE DEPARTING TO THE EAST. ASCENT AHEAD OF SUBTLE WAVE MOVING INTO WEST CENTRAL IL MAY ALSO BE PLAYING A ROLE. RECENT AIRCRAFT SOUNDINGS AND FORECAST RAP SOUNDINGS SHOW THE TOP OF THE MOIST LAYER NEAR -10C SUPPORTING NEEDLE AND COLUMN LIKE CRYSTALS. MAINLY NEEDLES APPEAR TO BE FALLING AT THE OFFICE AT THE MOMENT. THIS FINER CRYSTAL STRUCTURE SUGGESTS MINIMAL ACCUMULATION BUT A COATING TO A TENTH OR TWO IS IS LIKELY UNTIL THIS BETTER ORGANIZED SNOW BAND DEPARTS...WHICH SHOULD OCCUR IN THE NEXT FEW HOURS. HAVE INCREASED POPS FOR THE NEXT FEW HOURS AND ADDED SOME MINIMAL ACCUMULATION TO THE GRIDS. GIVEN THE SNOW FALLING...FREEZING DRIZZLE LOOKS TO HOLD OFF UNTIL LATER THIS EVENING AS THE SNOW DEPARTS AND COLUMN MOISTURE BECOMES MORE SHALLOW LEADING TO A LOWER PERCENTAGE OF ICE IN THE CLOUDS...BUT THIS STILL LOOKS TO BE PATCHY IN COVERAGE IF IT OCCURS. OTHERWISE VSBY LOOKS TO BE REDUCED IN MIST WHICH MAY BE ENOUGH TO PROVIDE SOME SLICK SPOTS ON SOLID SURFACES INTO THE OVERNIGHT BUT DENSE FREEZING/ACCUMULATING FOG IS NOT EXPECTED AT THIS TIME. MDB //PREV DISCUSSION... 339 PM CST MAIN FORECAST CHALLENGES/CONCERNS ARE WITH LIGHT SNOW OR LIGHT FREEZING DRIZZLE POTENTIAL LINGERING INTO THIS EVENING...POTENTIAL FOR FREEZING RAIN OR FREEZING DRIZZLE ONCE AGAIN FRIDAY MORNING...AND THEN A CONTINUED WARM UP WITH ALL RAIN LIKELY FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. CONCERNS IN THE NEAR TERM REMAIN WITH ONGOING LIGHT SNOW...AS WELL AS A TRANSITION TO EITHER LIGHT SNOW OR LIGHT FREEZING DRIZZLE LATE THIS AFTERNOON INTO THE EARLY EVENING. LATEST RADAR IMAGERY DEPICTING ONLY LIGHT RETURNS ON RADAR...WITH SURFACE OBS STILL REPORTING ALL SNOW ACROSS THE AREA. THIS SNOW HAS BEEN IN RESPONSE TO A SHORT WAVE TROUGH LIFTING EAST/NORTHEAST ACROSS THE REGION...AS WELL AS A WAA WING SWINGING A SWATH PRECIP ACROSS MAINLY THE SOUTHEAST TWO THIRDS OF THE CWA. AN OVERALL DIMINISHING TREND AS BEEN OBSERVED THIS PAST HOUR AND EXPECT THIS TO CONTINUE LATE THIS AFTERNOON...AS WITH THIS WEAK FORCING FURTHER WEAKENING WHILE SHIFTING EAST OUT OF THE AREA. SNOWFALL THIS PAST AFTERNOON HAS BEEN FROM A DUSTING UP TO A HALF INCH...VIA REPORTS FROM FACEBOOK/TWITTER...AND WOULD EXPECT AT MOST A COUPLE OF TENTHS OF AN INCH OF ADDITIONAL SNOWFALL THIS AFTERNOON. ALTHOUGH THERE STILL REMAINS CONCERNS FOR A TRANSITION OVER TO FREEZING DRIZZLE LATE THIS AFTERNOON...CONCERNS FOR ANY LONG DURATION/PREVAILING FREEZING DRIZZLE ARE BEGINNING TO LESSEN. AS DEEPER MOISTURE CONTINUES TO STREAM OVER THE REGION...PRECIP TYPE REMAINS ALL SNOW AT THIS HOUR. THROUGH THE 00Z TIME FRAME IT DOES APPEAR THAT THIS DEEPER MOISTURE IS LOSS...BUT STILL ON THE LOWER THRESHOLD FOR CRYSTALS TO BE PRESENT AND THUS FOR SNOW FOR MOST AREAS. 00Z AND BEYOND...CONTINUED LOSS OF THIS MOISTURE WILL OCCUR AND ITS DURING THIS TIME FRAME THAT I THINK THERE WILL BE THE POTENTIAL FOR LIGHT FREEZING DRIZZLE. ALTHOUGH...LATEST GUIDANCE IN FAIR AGREEMENT WITH THE BETTER LIFT/OMEGA IN THE LOWER LEVEL MOIST LAYER TO BEGIN SHIFTING EAST OF THE CWA ALSO DURING THIS TIME. SO DO FEEL THAT THERE IS STILL POTENTIAL FOR LIGHT FREEZING DRIZZLE THIS EVENING...THINK ITS A SMALL WINDOW FOR THIS OPPORTUNITY BEFORE ALL LIFT DEPARTS. HAVE TRENDED THE GRIDS THIS WAY FOR THIS EVENING...BUT DID LEAVE PATCHY FREEZING DRIZZLE IN OVERNIGHT FOR MOST AREAS. LATEST SATELLITE IMAGERY/OBSERVATIONS DEPICTING LOW LEVEL MOISTURE STILL WORKING ITS WAY NORTH ACROSS THE REGION. IN THE HIGHLY SATURATED LOWER LEVELS...CONCERNED THAT THIS PATCHY LIGHT FREEZING DRIZZLE COULD STILL OCCUR. AM NOT EXPECTING MUCH IN TERMS OF ICE ACCUMULATION...BUT CANNOT RULE OUT ISOLATED SLIPPERY CONDITIONS TO DEVELOP. TEMPERATURES LATE THIS AFTERNOON/EARLY EVENING WILL BE OUR LOWS FOR THE NIGHT...AS STRONG WAA CONTINUES TONIGHT WITH RISING TEMPS EXPECTED TONIGHT INTO FRIDAY MORNING. DESPITE WARMING TEMPS THROUGH EARLY FRIDAY MORNING...SURFACE TEMPS WILL STILL BE AT OR JUST BELOW FREEZING THROUGH MID LATE MORNING. ASCENT WILL BE ON THE INCREASE ON FRIDAY AS A STRONG MID/UPPER LEVEL TROUGH SHIFTS EAST ACROSS THE CENTRAL PLAINS. WITH THERMAL PROFILES DURING THIS TIME SUPPORTIVE OF ALL LIQUID...AM STILL CONCERNED THAT A BRIEF PERIOD OF FREEZING RAIN COULD OCCUR. THE QUESTIONS WILL BE IF FORCING/PRECIP RETURNS SOON ENOUGH BEFORE TEMPS RISE ABOVE FREEZING. ALTHOUGH DO FEEL THAT THIS BETTER PRECIP AXIS WONT ARRIVE UNTIL TEMPS RISE AT OR ABOVE FREEZING BY THIS MID LATE MORNING PERIOD. IF FREEZING RAIN DOES OCCUR...IT SHOULD BE A NARROW TIME FRAME WITH THE WEST/SOUTHWEST AREAS IN A MORE PREFERRED LOCATION IN THE MORNING...AND POSSIBLY FOR THE FAR NORTHWEST CWA THROUGH MID DAY. CONTINUED WARMING CONTINUES INTO THE AFTERNOON WITH ALL RAIN THEN OCCURRING FRIDAY AFTERNOON INTO FRIDAY NIGHT FOR ALL AREAS...WITH THREE QUARTERS OF AN INCH TO ONE INCH POSSIBLE AREA WIDE. LATEST TRENDS HAVE BEEN FOR A QUICKER TRANSITION BACK TOWARDS SNOW LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING...WITH ALL SNOW LIKELY THEN SATURDAY BEFORE THIS PRECIP EXITS. ALTHOUGH ANY LINGERING SNOW SHOULD BE ON THE LIGHT SIDE...AND DONT ANTICIPATE ANY ADDITIONAL SNOW ACCUMULATION. RODRIGUEZ && .HYDROLOGY... 339 PM CST ALSO OF INTEREST THIS FORECAST CONTINUE TO BE WITH HYDROLOGIC ISSUES...WITH A WARMER AND MORE MOIST AIR MASS MOVING NORTH ACROSS THE REGION TONIGHT THROUGH FRIDAY. THIS WILL ALLOW FOR A TRANSITION TO ALL RAIN BY MID DAY FRIDAY...CONTINUING INTO EARLY SATURDAY MORNING. RAINFALL TOTALS OF THREE QUARTERS OF AN INCH TO ONE INCH ARE POSSIBLE AREA WIDE FROM FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. CONCERNS WITH THE WARM UP...RAINFALL...FROZEN GROUND WITH CURRENT SNOWPACK IN PLACE COULD ALL RESULT IN RISES IN AREA RIVERS/STREAMS/CREEKS AS WELL AS POTENTIAL FOR FLOODING AND ICE JAM FLOODING. CONFIDENCE IS NOT TOO HIGH WITH REGARDS TO THE EXTENT OF THE SNOWMELT...NONETHELESS...THE PREVIOUSLY MENTIONED CONCERNS WARRANT CONTINUED CLOSE MONITOR OF THIS SITUATION INTO THE WEEKEND. FOR MORE INFORMATION ON THIS FLOOD POTENTIAL SEE THE HYDROLOGIC OUTLOOK ISSUED EARLIER THIS AFTERNOON...ESF. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * LIFR CIGS POSSIBLY DROPPING TO VLIFR THIS MORNING * SMALL CHANCE OF -FZDZ THIS MORNING * DENSE FOG POSSIBLE THIS MORNING INTO THE EARLY AFTERNOON * RAIN DEVELOPS LATE THIS AFTERNOON AND CONTINUES THROUGH MID EVENING...SOME MINOR IMPROVEMENTS TO CIGS/VSBY LIKELY WITH THE RAIN IZZI //DISCUSSION...UPDATED 09Z... BIGGEST CHANGE FROM THE 06Z TAFS WAS TO BRING CONDITIONS. CIGS AND VSBYS HAVE TRENDED SHARPLY DOWNWARD THE PAST COUPLE HOURS AND CANT THINK OF ANY GOOD REASON FOR ANY SUSTAINED IMPROVEMENT UNTIL STEADY RAIN DEVELOPS LATE THIS AFTERNOON. CONTINUE TO ERR ON THE OPTIMISTIC SIDE WITH REGARDS TO VSBY...BUT STILL THINK THERE IS A PRETTY GOOD CHANCE THAT MDW WILL BE DROPPING BELOW RVR MINIMUMS THIS MORNING AND REMAIN THERE INTO THE AFTERNOON AS PROGRESSIVELY HIGHER DEWPOINTS ARE ADVECTED NORTH OVER THE DEEP SNOW PACK. IZZI UPDATED 06Z... WARM FRONT WILL LIFT NORTHWARD ACROSS THE REGION FRIDAY WITH A PRETTY STRONG SURGE OF MOIST AND FAIRLY MILD AIR MOVING UP INTO THE AREA OVER A DENSE SNOW PACK. ALREADY HAVE WIDESPREAD LIFR CIGS UPSTREAM HEADING INTO THE AREA AND ANTICIPATE CONDITIONS TO LIKELY TO CONTINUE TO DETERIORATE THROUGH THE NIGHT AND PROBABLY FRIDAY MORNING AS WELL. SUSPECT THAT IF ANYTHING THESE TAFS ARE OPTIMISTIC WITH REGARDS TO CIGS/VSBY WITH AT LEAST SOME POTENTIAL FOR DENSE FOG AND VV001 DEVELOPING FRIDAY MORNING...BUT RELUCTANT TO TREND THAT LOW YET DUE TO LACK OF CONFIDENCE. ALSO CONCERNED THAT SOME FZDZ COULD DEVELOP FOR A TIME FRIDAY MORNING BEFORE TEMPERATURES RISE ABOVE FREEZING...BUT FORECAST SOUNDINGS SUGGEST FAIRLY SHALLOW MOIST LAYER UNTIL CLOSER TO MIDDAY BY WHICH TIME TEMPS SHOULD BE ABOVE FREEZING. IF DZ MATERIALIZES SOONER THAN EXPECTED THEN A PERIOD OF FZDZ WOULD BE POSSIBLE FRIDAY MORNING. STEADY RAIN DEVELOPS LATE FRIDAY AFTERNOON LIKELY MIXING OUT THE LOWEST CIGS WITH SOME IMPROVEMENT IN CONDITIONS AT THAT TIME...BUT LIKELY TO REMAIN IFR. RAIN SHOULD TAPER OFF TO MORE OCNL -SHRA OR -DZ LATER FRIDAY EVENING INTO THE OVERNIGHT WITH IFR PROBABLY CONTINUING. IZZI //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE IN LIFR OR LOWER CONDITIONS THROUGH EARLY THIS AFTERNOON * LOW CONFIDENCE IN POTENTIAL FOR VLIFR IN DENSE FOG THIS MORNING * HIGH CONFIDENCE IN TIMING OF ONSET OF STEADIER RAIN +/- AN HOUR OR SO * LOW CONFIDENCE IN POTENTIAL FOR FZDZ THIS MORNING IZZI //OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z... 00Z... SATURDAY...GUSTY WEST WINDS WITH A CHANCE OF -SN WITH IFR/MVFR POSSIBLE EARLY. VFR/WX NIL OVERNIGHT. SUNDAY...GUSTY SOUTH WINDS. VFR/WX NIL EARLY. SLIGHT CHANCE OF RAIN OR SNOW WITH MVFR POSSIBLE OVERNIGHT. MONDAY...VFR/WX NIL. TUESDAY...SLIGHT CHANCE OF SNOW. MVFR POSSIBLE. WEDNESDAY...VFR/WX NIL. KJB && .MARINE... 219 PM CST BROAD SURFACE RIDGE ALONG THE EASTERN SEABOARD STRETCHES FROM QUEBEC SOUTH THROUGH THE CAROLINAS...WITH AN INFLUENCING REMAINING ACROSS THE WESTERN GREAT LAKES THIS AFTERNOON. THE LARGEST INFLUENCE HAS BEEN THE LACK OF A GRADIENT...WHICH HAS RESULTED IN WINDS BEING MUCH LIGHTER THAN EARLIER ANTICIPATED. THUS HAVE SLOWED THE WIND SPEEDS DOWN...AND ALSO HAS RESULTED IN WINDS REMAINING MORE SOUTHEASTERLY. A BOUNDARY WAS LIFTING NORTH ACROSS THE OHIO VALLEY...AND WILL LIKELY REACH THE SOUTHERN PORTIONS OF THE LAKE OVERNIGHT THEN ALLOW WINDS TO TURN MORE SOUTHERLY FOR THE LAKE. OVERNIGHT INTO FRIDAY GUIDANCE CONTINUES TO SUGGEST THE LACK OF A GRADIENT WILL REMAIN WEST OF LAKE MICHIGAN...THEN THE CHANNEL OF BETTER WINDS WILL EVENTUALLY SLIDE EAST/SOUTHEAST ACROSS THE LAKE FRIDAY AFTERNOON/EVENING. SFC FLOW WILL REMAIN SOUTHERLY...WITH SPEEDS GENERALLY AROUND 20 TO 30 KT. AT THIS TIME IT APPEARS HAZARDOUS WINDS FOR SMALL CRAFT WILL DEVELOP AROUND THIS TIME AS WELL. THEN THE FOCUS FOR THE WEEKEND WILL BE ON A DEVELOPING LOW PRESSURE SYSTEM THAT IS EXPECTED TO DEVELOP ACROSS THE SOUTHERN PLAINS...WHICH WILL EVENTUALLY LIFT NORTHEAST ACROSS LATE SATURDAY MORNING. THE GRADIENT WILL TIGHTEN SATURDAY EVENING...POSSIBLY BRINGING SOME OCCASIONAL GUSTS TO 30 KT. THEN THE GRADIENT BEGINS TO SLACKEN OFF THROUGH EARLY SUNDAY. YET ANOTHER LOW PRESSURE SYSTEM IS EXPECTED TO SLIDE EAST ACROSS THE UPPER MIDWEST SUN AFTN...WITH THE GRADIENT TIGHTENING YET AGAIN FOR LAKE MICHIGAN. CURRENT FORECAST GUIDANCE INDICATES THE POSSIBILITY OF OCCASIONAL GALE FORCE GUSTS FOR THE OPEN WATERS SUN LATE AFTN/EVE. THE PATTERN REMAINS RELATIVELY ACTIVE FOR EARLY NEXT WEEK...WITH ANOTHER LOW PRESSURE SYSTEM POISED TO SLIDE SOUTHEAST FROM THE UPPER MIDWEST INTO THE GREAT LAKES. THE GRADIENT WILL ONCE AGAIN TIGHTEN...WITH WINDS EVENTUALLY TURNING WEST/NORTHWESTERLY TUE NGT/WED. THE AMOUNT OF ICE REMAINS HIGH ACROSS NEARSHORE WATERS AS SEEN IN WEBCAMS AND SATELLITE IMAGERY. THUS WAVES WILL BE OMITTED FROM THE NEARSHORE FORECAST. BEACHLER && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1137 PM CST THU JAN 9 2014 .DISCUSSION... 816 PM CST RADAR MOSAIC SHOWS CONTINUED LIGHT SNOW ACROSS MUCH OF THE EASTERN CWA FROM NEAR PONTIAC NORTHEAST TO THE NORTHERN CHICAGO METRO. WARM ASCENT CONTINUES ABOVE WITH ADDITIONAL ASCENT LOOKING TO BE PROVIDED BY AN ELONGATED AREA OF CYCLONIC VORTICITY TRAILING A SHORTWAVE DEPARTING TO THE EAST. ASCENT AHEAD OF SUBTLE WAVE MOVING INTO WEST CENTRAL IL MAY ALSO BE PLAYING A ROLE. RECENT AIRCRAFT SOUNDINGS AND FORECAST RAP SOUNDINGS SHOW THE TOP OF THE MOIST LAYER NEAR -10C SUPPORTING NEEDLE AND COLUMN LIKE CRYSTALS. MAINLY NEEDLES APPEAR TO BE FALLING AT THE OFFICE AT THE MOMENT. THIS FINER CRYSTAL STRUCTURE SUGGESTS MINIMAL ACCUMULATION BUT A COATING TO A TENTH OR TWO IS IS LIKELY UNTIL THIS BETTER ORGANIZED SNOW BAND DEPARTS...WHICH SHOULD OCCUR IN THE NEXT FEW HOURS. HAVE INCREASED POPS FOR THE NEXT FEW HOURS AND ADDED SOME MINIMAL ACCUMULATION TO THE GRIDS. GIVEN THE SNOW FALLING...FREEZING DRIZZLE LOOKS TO HOLD OFF UNTIL LATER THIS EVENING AS THE SNOW DEPARTS AND COLUMN MOISTURE BECOMES MORE SHALLOW LEADING TO A LOWER PERCENTAGE OF ICE IN THE CLOUDS...BUT THIS STILL LOOKS TO BE PATCHY IN COVERAGE IF IT OCCURS. OTHERWISE VSBY LOOKS TO BE REDUCED IN MIST WHICH MAY BE ENOUGH TO PROVIDE SOME SLICK SPOTS ON SOLID SURFACES INTO THE OVERNIGHT BUT DENSE FREEZING/ACCUMULATING FOG IS NOT EXPECTED AT THIS TIME. MDB //PREV DISCUSSION... 339 PM CST MAIN FORECAST CHALLENGES/CONCERNS ARE WITH LIGHT SNOW OR LIGHT FREEZING DRIZZLE POTENTIAL LINGERING INTO THIS EVENING...POTENTIAL FOR FREEZING RAIN OR FREEZING DRIZZLE ONCE AGAIN FRIDAY MORNING...AND THEN A CONTINUED WARM UP WITH ALL RAIN LIKELY FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. CONCERNS IN THE NEAR TERM REMAIN WITH ONGOING LIGHT SNOW...AS WELL AS A TRANSITION TO EITHER LIGHT SNOW OR LIGHT FREEZING DRIZZLE LATE THIS AFTERNOON INTO THE EARLY EVENING. LATEST RADAR IMAGERY DEPICTING ONLY LIGHT RETURNS ON RADAR...WITH SURFACE OBS STILL REPORTING ALL SNOW ACROSS THE AREA. THIS SNOW HAS BEEN IN RESPONSE TO A SHORT WAVE TROUGH LIFTING EAST/NORTHEAST ACROSS THE REGION...AS WELL AS A WAA WING SWINGING A SWATH PRECIP ACROSS MAINLY THE SOUTHEAST TWO THIRDS OF THE CWA. AN OVERALL DIMINISHING TREND AS BEEN OBSERVED THIS PAST HOUR AND EXPECT THIS TO CONTINUE LATE THIS AFTERNOON...AS WITH THIS WEAK FORCING FURTHER WEAKENING WHILE SHIFTING EAST OUT OF THE AREA. SNOWFALL THIS PAST AFTERNOON HAS BEEN FROM A DUSTING UP TO A HALF INCH...VIA REPORTS FROM FACEBOOK/TWITTER...AND WOULD EXPECT AT MOST A COUPLE OF TENTHS OF AN INCH OF ADDITIONAL SNOWFALL THIS AFTERNOON. ALTHOUGH THERE STILL REMAINS CONCERNS FOR A TRANSITION OVER TO FREEZING DRIZZLE LATE THIS AFTERNOON...CONCERNS FOR ANY LONG DURATION/PREVAILING FREEZING DRIZZLE ARE BEGINNING TO LESSEN. AS DEEPER MOISTURE CONTINUES TO STREAM OVER THE REGION...PRECIP TYPE REMAINS ALL SNOW AT THIS HOUR. THROUGH THE 00Z TIME FRAME IT DOES APPEAR THAT THIS DEEPER MOISTURE IS LOSS...BUT STILL ON THE LOWER THRESHOLD FOR CRYSTALS TO BE PRESENT AND THUS FOR SNOW FOR MOST AREAS. 00Z AND BEYOND...CONTINUED LOSS OF THIS MOISTURE WILL OCCUR AND ITS DURING THIS TIME FRAME THAT I THINK THERE WILL BE THE POTENTIAL FOR LIGHT FREEZING DRIZZLE. ALTHOUGH...LATEST GUIDANCE IN FAIR AGREEMENT WITH THE BETTER LIFT/OMEGA IN THE LOWER LEVEL MOIST LAYER TO BEGIN SHIFTING EAST OF THE CWA ALSO DURING THIS TIME. SO DO FEEL THAT THERE IS STILL POTENTIAL FOR LIGHT FREEZING DRIZZLE THIS EVENING...THINK ITS A SMALL WINDOW FOR THIS OPPORTUNITY BEFORE ALL LIFT DEPARTS. HAVE TRENDED THE GRIDS THIS WAY FOR THIS EVENING...BUT DID LEAVE PATCHY FREEZING DRIZZLE IN OVERNIGHT FOR MOST AREAS. LATEST SATELLITE IMAGERY/OBSERVATIONS DEPICTING LOW LEVEL MOISTURE STILL WORKING ITS WAY NORTH ACROSS THE REGION. IN THE HIGHLY SATURATED LOWER LEVELS...CONCERNED THAT THIS PATCHY LIGHT FREEZING DRIZZLE COULD STILL OCCUR. AM NOT EXPECTING MUCH IN TERMS OF ICE ACCUMULATION...BUT CANNOT RULE OUT ISOLATED SLIPPERY CONDITIONS TO DEVELOP. TEMPERATURES LATE THIS AFTERNOON/EARLY EVENING WILL BE OUR LOWS FOR THE NIGHT...AS STRONG WAA CONTINUES TONIGHT WITH RISING TEMPS EXPECTED TONIGHT INTO FRIDAY MORNING. DESPITE WARMING TEMPS THROUGH EARLY FRIDAY MORNING...SURFACE TEMPS WILL STILL BE AT OR JUST BELOW FREEZING THROUGH MID LATE MORNING. ASCENT WILL BE ON THE INCREASE ON FRIDAY AS A STRONG MID/UPPER LEVEL TROUGH SHIFTS EAST ACROSS THE CENTRAL PLAINS. WITH THERMAL PROFILES DURING THIS TIME SUPPORTIVE OF ALL LIQUID...AM STILL CONCERNED THAT A BRIEF PERIOD OF FREEZING RAIN COULD OCCUR. THE QUESTIONS WILL BE IF FORCING/PRECIP RETURNS SOON ENOUGH BEFORE TEMPS RISE ABOVE FREEZING. ALTHOUGH DO FEEL THAT THIS BETTER PRECIP AXIS WONT ARRIVE UNTIL TEMPS RISE AT OR ABOVE FREEZING BY THIS MID LATE MORNING PERIOD. IF FREEZING RAIN DOES OCCUR...IT SHOULD BE A NARROW TIME FRAME WITH THE WEST/SOUTHWEST AREAS IN A MORE PREFERRED LOCATION IN THE MORNING...AND POSSIBLY FOR THE FAR NORTHWEST CWA THROUGH MID DAY. CONTINUED WARMING CONTINUES INTO THE AFTERNOON WITH ALL RAIN THEN OCCURRING FRIDAY AFTERNOON INTO FRIDAY NIGHT FOR ALL AREAS...WITH THREE QUARTERS OF AN INCH TO ONE INCH POSSIBLE AREA WIDE. LATEST TRENDS HAVE BEEN FOR A QUICKER TRANSITION BACK TOWARDS SNOW LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING...WITH ALL SNOW LIKELY THEN SATURDAY BEFORE THIS PRECIP EXITS. ALTHOUGH ANY LINGERING SNOW SHOULD BE ON THE LIGHT SIDE...AND DONT ANTICIPATE ANY ADDITIONAL SNOW ACCUMULATION. RODRIGUEZ && .HYDROLOGY... ALSO OF INTEREST THIS FORECAST CONTINUE TO BE WITH HYDROLOGIC ISSUES...WITH A WARMER AND MORE MOIST AIR MASS MOVING NORTH ACROSS THE REGION TONIGHT THROUGH FRIDAY. THIS WILL ALLOW FOR A TRANSITION TO ALL RAIN BY MID DAY FRIDAY...CONTINUING INTO EARLY SATURDAY MORNING. RAINFALL TOTALS OF THREE QUARTERS OF AN INCH TO ONE INCH ARE POSSIBLE AREA WIDE FROM FRIDAY AFTERNOON THROUGH EARLY SATURDAY MORNING. CONCERNS WITH THE WARM UP...RAINFALL...FROZEN GROUND WITH CURRENT SNOWPACK IN PLACE COULD ALL RESULT IN RISES IN AREA RIVERS/STREAMS/CREEKS AS WELL AS POTENTIAL FOR FLOODING AND ICE JAM FLOODING. CONFIDENCE IS NOT TOO HIGH WITH REGARDS TO THE EXTENT OF THE SNOWMELT...NONETHELESS...THE PREVIOUSLY MENTIONED CONCERNS WARRANT CONTINUED CLOSE MONITOR OF THIS SITUATION INTO THE WEEKEND. FOR MORE INFORMATION ON THIS FLOOD POTENTIAL SEE THE HYDROLOGIC OUTLOOK ISSUED EARLIER THIS AFTERNOON...ESF. RODRIGUEZ && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * IFR CIGS LIKELY TREND DOWN TO LIFR OVERNIGHT OR EARLY FRI AM * VLIFR/DENSE FOG POSSIBLE FRIDAY MORNING INTO THE EARLY AFTERNOON * RAIN DEVELOPS LATE FRIDAY AFTERNOON AND CONTINUES THROUGH MID EVENING FRIDAY...SOME MINOR IMPROVEMENTS TO CIGS/VSBY LIKELY WITH THE RAIN IZZI //DISCUSSION...UPDATED 06Z... WARM FRONT WILL LIFT NORTHWARD ACROSS THE REGION FRIDAY WITH A PRETTY STRONG SURGE OF MOIST AND FAIRLY MILD AIR MOVING UP INTO THE AREA OVER A DENSE SNOW PACK. ALREADY HAVE WIDESPREAD LIFR CIGS UPSTREAM HEADING INTO THE AREA AND ANTICIPATE CONDITIONS TO LIKELY TO CONTINUE TO DETERIORATE THROUGH THE NIGHT AND PROBABLY FRIDAY MORNING AS WELL. SUSPECT THAT IF ANYTHING THESE TAFS ARE OPTIMISTIC WITH REGARDS TO CIGS/VSBY WITH AT LEAST SOME POTENTIAL FOR DENSE FOG AND VV001 DEVELOPING FRIDAY MORNING...BUT RELUCTANT TO TREND THAT LOW YET DUE TO LACK OF CONFIDENCE. ALSO CONCERNED THAT SOME FZDZ COULD DEVELOP FOR A TIME FRIDAY MORNING BEFORE TEMPERATURES RISE ABOVE FREEZING...BUT FORECAST SOUNDINGS SUGGEST FAIRLY SHALLOW MOIST LAYER UNTIL CLOSER TO MIDDAY BY WHICH TIME TEMPS SHOULD BE ABOVE FREEZING. IF DZ MATERIALIZES SOONER THAN EXPECTED THEN A PERIOD OF FZDZ WOULD BE POSSIBLE FRIDAY MORNING. STEADY RAIN DEVELOPS LATE FRIDAY AFTERNOON LIKELY MIXING OUT THE LOWEST CIGS WITH SOME IMPROVEMENT IN CONDITIONS AT THAT TIME...BUT LIKELY TO REMAIN IFR. RAIN SHOULD TAPER OFF TO MORE OCNL -SHRA OR -DZ LATER FRIDAY EVENING INTO THE OVERNIGHT WITH IFR PROBABLY CONTINUING. IZZI //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN IFR OR LOWER CONDITIONS THROUGH FRIDAY EVENING * LOW CONFIDENCE IN POTENTIAL FOR VLIFR IN DENSE FOG FRIDAY * HIGH CONFIDENCE IN TIMING OF ONSET OF STEADIER RAIN +/- AN HOUR OR SO * LOW CONFIDENCE IN POTENTIAL FOR FZDZ FRIDAY MORNING IZZI //OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z... 00Z... SATURDAY...GUSTY WEST WINDS WITH A CHANCE OF -SN WITH IFR/MVFR POSSIBLE EARLY. VFR/WX NIL OVERNIGHT. SUNDAY...GUSTY SOUTH WINDS. VFR/WX NIL EARLY. SLIGHT CHANCE OF RAIN OR SNOW WITH MVFR POSSIBLE OVERNIGHT. MONDAY...VFR/WX NIL. TUESDAY...SLIGHT CHANCE OF SNOW. MVFR POSSIBLE. WEDNESDAY...VFR/WX NIL. KJB && .MARINE... 219 PM CST BROAD SURFACE RIDGE ALONG THE EASTERN SEABOARD STRETCHES FROM QUEBEC SOUTH THROUGH THE CAROLINAS...WITH AN INFLUENCING REMAINING ACROSS THE WESTERN GREAT LAKES THIS AFTERNOON. THE LARGEST INFLUENCE HAS BEEN THE LACK OF A GRADIENT...WHICH HAS RESULTED IN WINDS BEING MUCH LIGHTER THAN EARLIER ANTICIPATED. THUS HAVE SLOWED THE WIND SPEEDS DOWN...AND ALSO HAS RESULTED IN WINDS REMAINING MORE SOUTHEASTERLY. A BOUNDARY WAS LIFTING NORTH ACROSS THE OHIO VALLEY...AND WILL LIKELY REACH THE SOUTHERN PORTIONS OF THE LAKE OVERNIGHT THEN ALLOW WINDS TO TURN MORE SOUTHERLY FOR THE LAKE. OVERNIGHT INTO FRIDAY GUIDANCE CONTINUES TO SUGGEST THE LACK OF A GRADIENT WILL REMAIN WEST OF LAKE MICHIGAN...THEN THE CHANNEL OF BETTER WINDS WILL EVENTUALLY SLIDE EAST/SOUTHEAST ACROSS THE LAKE FRIDAY AFTERNOON/EVENING. SFC FLOW WILL REMAIN SOUTHERLY...WITH SPEEDS GENERALLY AROUND 20 TO 30 KT. AT THIS TIME IT APPEARS HAZARDOUS WINDS FOR SMALL CRAFT WILL DEVELOP AROUND THIS TIME AS WELL. THEN THE FOCUS FOR THE WEEKEND WILL BE ON A DEVELOPING LOW PRESSURE SYSTEM THAT IS EXPECTED TO DEVELOP ACROSS THE SOUTHERN PLAINS...WHICH WILL EVENTUALLY LIFT NORTHEAST ACROSS LATE SATURDAY MORNING. THE GRADIENT WILL TIGHTEN SATURDAY EVENING...POSSIBLY BRINGING SOME OCCASIONAL GUSTS TO 30 KT. THEN THE GRADIENT BEGINS TO SLACKEN OFF THROUGH EARLY SUNDAY. YET ANOTHER LOW PRESSURE SYSTEM IS EXPECTED TO SLIDE EAST ACROSS THE UPPER MIDWEST SUN AFTN...WITH THE GRADIENT TIGHTENING YET AGAIN FOR LAKE MICHIGAN. CURRENT FORECAST GUIDANCE INDICATES THE POSSIBILITY OF OCCASIONAL GALE FORCE GUSTS FOR THE OPEN WATERS SUN LATE AFTN/EVE. THE PATTERN REMAINS RELATIVELY ACTIVE FOR EARLY NEXT WEEK...WITH ANOTHER LOW PRESSURE SYSTEM POISED TO SLIDE SOUTHEAST FROM THE UPPER MIDWEST INTO THE GREAT LAKES. THE GRADIENT WILL ONCE AGAIN TIGHTEN...WITH WINDS EVENTUALLY TURNING WEST/NORTHWESTERLY TUE NGT/WED. THE AMOUNT OF ICE REMAINS HIGH ACROSS NEARSHORE WATERS AS SEEN IN WEBCAMS AND SATELLITE IMAGERY. THUS WAVES WILL BE OMITTED FROM THE NEARSHORE FORECAST. BEACHLER && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
433 AM EST FRI JAN 10 2014 .SYNOPSIS... ISSUED AT 420 AM EST FRI JAN 10 2014 SOME PATCHY DRIZZLE OF FREEZING DRIZZLE CAN BE EXPECTED THIS MORNING AS AN UPPER LEVEL DISTURBANCE SHIFTS EAST OF THE AREA. A STRONGER UPPER LEVEL DISTURBANCE WILL CONTINUE TO TAKE SHAPE ACROSS THE PLAINS TODAY AND WILL TRACK EASTWARD TONIGHT BRINGING WIDESPREAD RAIN TO THE AREA. RAIN WILL TAPER FROM WEST TO EAST LATE TONIGHT INTO EARLY SATURDAY. HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE MID AND UPPER 30S ACROSS CENTRAL LOWER MICHIGAN TO THE LOWER TO MID 40S FROM CENTRAL INDIANA INTO WEST CENTRAL OHIO. LOW TEMPERATURES TONIGHT WILL DROP INTO THE MID AND UPPER 30S FOR MOST LOCATIONS...WITH LOWER 40S ACROSS WEST CENTRAL OHIO. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 420 AM EST FRI JAN 10 2014 BRIEF LULL IN MEASURABLE PRECIP IS SETTING UP THIS MORNING AS STRONGEST DPVA WITH COMPACT SHORT WAVE HAS SHIFTED INTO NORTHWEST OHIO...AND THIS FORCING WILL QUICKLY TRANSLATE EASTWARD THIS MORNING OUT OF THE FORECAST AREA. REDUCED STATIC STABILITY IN THE MID LEVELS AND STEEP MID/UPPER LEVEL LAPSE RATES HAVE ALLOWED SECONDARY BLOSSOMING OF RADAR RETURNS PAST FEW HOURS ACROSS FAR SOUTHEAST PORTIONS OF THE AREA. HOWEVER...DRIER MID LEVEL AIR IS ALREADY ADVECTING ACROSS THESE LOCATIONS WITH RAP SHORT TERM BUFFER SOUNDINGS INDICATING TRANSITION TO MORE OF A LIGHT FREEZING DRIZZLE PRECIP TYPE. WEAK UPPER LEVEL SHORT WAVE RIDGING/SUBSIDENCE WILL CONTINUE TO BUILD INTO THE AREA FOR A SHORT TERM THIS MORNING WITH ONLY VERY SHALLOW AND WEAK VERTICAL MOTIONS THIS MORNING. SECONDARY LOW LEVEL ISENTROPIC SURGE APPEARS TO BE TAKING SHAPE ACROSS CENTRAL INDIANA WITH SECONDARY WARM FRONT...AND REGIONAL RADAR MOSAIC/SFC OBS HAVE BEEN INDICATING INCREASING -DZ/-FZDZ ACROSS CENTRAL INDIANA. EXPECTING DRIZZLE TO INCREASE IN COVERAGE TOWARD 12Z ACROSS THE AREA WITH NEAR SFC WET BULBS VERY MARGINAL IN TERMS OF SUPPORTING DRIZZLE OR FREEZING DRIZZLE...PARTICULARLY ACROSS THE FAR SOUTH. WILL KEEP -FZDZ MENTION GOING THIS MORNING AND HAVE MAINTAINED NATURE OF PREVIOUS FORECAST IN SOUTH TO NORTH EVOLUTION THROUGH THE MORNING HOURS OF TRANSITION FROM -FZDZ TO -DZ. WITH LOW CONFIDENCE IN EXTENT/INTENSITY OF ANY FZDZ THIS MORNING AND INCREASING MARGINAL LOW LEVEL WET BULB PROFILES WILL HOLD OFF ON ANY HEADLINES AND CONTINUE MENTION IN MORNING HWO. OTHERWISE A MILDER DAY IN STORE ALTHOUGH SOLID SNOWPACK ACROSS THE AREA WILL LIMIT EXTENT OF SFC WARMUP WITH WAA...WITH HIGHS GENERALLY FROM MID 30S TO AROUND 40. FOG ALSO EXPECTED TO BECOME MORE PREVALENT TODAY FROM SOUTHWEST TO NORTHEAST WITH LOW LEVEL MOISTURE ADVECTION OVER SNOWPACK. FOCUS FOR THE REMAINDER OF THE SHORT TERM WILL THEN SHIFT TO INCREASING RAIN POTENTIAL LATER THIS AFTERNOON INTO TONIGHT ALONG WITH POTENTIAL HYDROLOGIC IMPACTS. WATER VAPOR IMAGERY EARLY THIS MORNING DEPICTS DIGGING UPPER TROUGH APPROACHING THE CENTRAL PLAINS WITH SECONDARY WEAKER SHORT WAVE APPROACHING WEST TEXAS. MODEL GUIDANCE HAS BEEN FAIRLY CONSISTENT IN MAINTAINING AN UNPHASED NATURE WITH THESE TWO SHORT WAVES...QUICKLY TAKING THE WEST TEXAS VORT MAX INTO THE WESTERN GREAT LAKES THIS EVENING. BROAD WARM/MOIST ADVECTION TO OCCUR TODAY...WITH MORE FOCUSED AXIS OF DEEPER MOISTURE SETTING UP IN VICINITY OF LOW/MID LEVEL CONFLUENCE ZONE ACROSS THE WESTERN GREAT LAKES. HAVE CONTINUED UPWARD TREND TO CATEGORICAL POPS FOR LATE THIS AFTERNOON ACROSS APPROXIMATELY WESTERN THIRD OF THE AREA WITH PERIODS OF MODERATE RAIN EXPECTED IN THE 21Z-03Z TIMEFRAME. ON HEELS OF THIS LEAD WAVE...EXPECTING LARGER SCALE FRONTAL RESPONSE TO INCREASE ACROSS THE MID MS RIVER VALLEY EARLY THIS EVENING IN ADVANCE OF MORE AMPLIFIED CENTRAL PLAINS TROUGH. A STRONG LLJ WILL VEER THIS EVENING IN ADVANCE OF THIS TROUGH AND SHOULD ADVECT PRIMARY LOW LEVEL THERMAL/MOIST AXIS ACROSS SERN PORTIONS OF THE FORECAST AREA LATER THIS EVENING INTO THE OVERNIGHT HOURS. PREFRONTAL CONVERGENCE AXIS SHOULD BE PROGRESSIVE ACROSS THE AREA SO CONFIDENCE SOMEWHAT LOW ON EXACT RAINFALL AMOUNTS ACROSS SOUTHEAST OF THE AREA WITH POTENTIAL OF HEAVIEST AMOUNTS REMAINING JUST TO EAST AND SOUTHEAST. HAVE MADE VERY FEW CHANGES TO PREVIOUS FORECAST WITH RAINFALL AMOUNTS IN THE HALF INCH TO INCH RANGE. IN ADDITION TO THIS RAIN...EXISTING SNOWPACK DOES CONTAIN 1 TO 2 INCHES OF LIQUID EQUIVALENT...WITH 2+ INCHES ACROSS THE FAR NORTH ACROSS SOUTHERN LOWER MICHIGAN. STILL SOME UNCERTAINTY AS TO EXTENT/TIMING OF RUNOFF FROM RAIN/SNOWMELT GIVEN FLUCTUATING SFC TEMPS OVER THE NEXT FEW DAYS. IF HIGHER END OF FORECASTED RAINFALL AMOUNTS DO OCCUR...PORTIONS OF MAUMEE AND WABASH RIVER BASINS STILL APPEAR TO STAND GREATEST RISK OF MINOR FLOODING OVER NEXT FEW DAYS GIVEN WARMER LOW LEVEL PROFILES AND GREATER RUNOFF FROM SNOWMELT. ACROSS THE FAR NORTH WHERE GREATER LIQUID EQUIVALENT IN SNOWPACK EXISTS...CONFIDENCE REMAINS SOMEWHAT LOWER IN TERMS OF EXTENT/TIMING OF SNOWMELT GIVEN COOLER LOW LEVEL TEMPS ACROSS THESE LOCATIONS. HOWEVER...GIVEN MORE FAVORABLE TRACK WITH INITIAL SHORT WAVE THIS EVENING...SOME LOCALLY HIGHER RAINFALL AMOUNTS ARE POSSIBLE TONIGHT ACROSS ESPECIALLY WESTERN PORTIONS OF ST. JOSEPH BASIN. WILL CONTINUE WITH ESF THIS MORNING TO DISCUSS POSSIBLE HYDRO IMPACTS OVER THE NEXT SEVERAL DAYS. && .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 420 AM EST FRI JAN 10 2014 VORT MAX WILL BE SWEEPING ACROSS THE CWA AT THE START OF THE PERIOD...WITH RAIN QUICKLY SHIFTING WEST TO EAST DURING THE MORNING HOURS AS COLD FRONT USHERS IN A QUICK SHOT OF COOLER AIR. THIS WILL ALLOW A BRIEF PERIOD FOR RAIN/SNOW MIX ACROSS THE AREA. HOWEVER...BY THIS POINT DEEPEST MSTR AND LIFT WILL BE SHIFTING EAST...KEEPING ANY ACCUMULATION POTENTIAL TO A MINIMUM. PREV FORECAST GENERALLY LEFT INTACT. 925 MB TEMPS WILL BOTTOM OUT AROUND -5 C BY LATE SAT NGT...TRANSLATING TO LOWS IN THE MID TO UPR 20S...STILL A GOOD 10 DEGREES OR MORE ABOVE NORMAL FOR MID JANUARY. UPPER LEVEL RIDGING WILL QUICKLY MOVE BACK IN BY SUNDAY WITH RETURN TO ABOVE NORMAL TEMPS IN TO THE 30S AND POSSIBLY LOW 40S WITH EFFECTS OF SNOWPACK BEING GREATLY REDUCED. TEMPS WILL STAY ABOVE FREEZING INTO MONDAY IN ADVANCE OF YET ANOTHER NORTHERN STREAM TROUGH TO BRING A CHANCE OF RAIN. A FEW OF THE MODELS SHOW POTENTIAL INTERACTION WITH SOUTHERN STREAM ENERGY BUT EVEN THE STRONGEST ECMWF ONLY SHOWS A SHARPENING OF THE PROGRESSIVE TROUGH. STATUS QUO FOR THE TIME BEING MON/MON NGT WITH CHC POPS AS BEST POTENTIAL REMAINS N AND S OF THE AREA. ACTIVE PATTERN CONTINUES WITH OVERALL LONGWAVE TROUGH REMAINING IN PLACE ACROSS THE GREAT LAKES WITH A STRONGER WAVE DROPPING THROUGH FOR MID WEEK. MODELS DIVERGE EVEN FURTHER WITH ECMWF CLOSING OFF A PROGRESSIVE UPPER LOW OVER THE CAROLINAS BY WEDNESDAY EVENING. WILL KEEP CONSERVATIVE LOW END POPS IN N AREAS THURSDAY AS MAIN TROUGH MOVES IN. TEMPERATURES WILL HOVER EITHER SIDE OF NORMAL WITH WARM UPS AHEAD OF EACH WAVE AND DROP TO SLIGHTLY BELOW NORMAL BEHIND IT. SOME INDICATIONS OF RETURN OF COLDER...BELOW NORMAL AIR OUTSIDE THE PERIOD BUT BY FAR MUCH WARMER THAN RECENT POLAR BLAST. FLOODING CONCERNS WILL LIKELY LINGER THROUGH MUCH OF THE PERIOD...BUT EXACT MAGNITUDE WILL BE TRICKY TO SORT OUT AS MUCH OF IT WILL FOCUS ON QPF OVER THE NEXT DAY OR SO. WILL CONTINUE WITH HWO MENTION INTO MID WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 420 AM EST FRI JAN 10 2014 VERY LITTLE CHANGE IN FORECAST THINKING FOR THE 06Z TAFS. STRONGEST DPVA WITH UPPER LEVEL VORT MAX WILL CONTINUE SLIDING THORUGH FAR NORTHEAST INDIANA OVER NEXT FEW HOURS. CONVECTIVE TYPE SNOW SHOWERS SHOULD TRANSITION TO MORE OF DRIZZLY STRATIFORM TYPE PRECIP OVERNIGHT AS MID LEVEL DRYING ENSUES BEHIND THIS SHORT WAVE. HAVE INCLUDED -FZDZSN MENTION AT KFWA BUT OVERALL IMPACTS SHOULD BE MINIMAL. IFR CONDITIONS SHOULD DETERIORATE TO LIFR WITH LOW LEVEL WARM/MOISTURE ADVECTION RAMPING UP OVER THE SNOWPACK ACROSS THE AREA. NEXT LARGER SCALE STORM SYSTEM WILL DEEPEN ACROSS THE PLAINS THIS AFTERNOON AND SHIFT EASTWARD TONIGHT...BRINGING WIDESPREAD RAIN TO THE TERMINALS FROM LATE THIS AFTERNOON THROUGH TONIGHT. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MARSILI SHORT TERM...MARSILI LONG TERM...FISHER AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
331 AM CST Fri Jan 10 2014 ...Updated for the long term discussion... .SYNOPSIS... ISSUED AT 1020 PM CST THU JAN 9 2014 The 10.00Z 250 hPa map showed strong NNW flow across the Pacific Northwest with magnitudes in the 120-130 kt range. Downstream, SW to W flow continued across the rest of the United States with magnitudes in the 90-100 kt range. At 500 hPa, a trof was moving across the central and northern Rockies. The KDDC raob showed a veering/warm air advection pattern in the low levels ahead of the aforementioned synoptic trof. At the sfc, a frontal boundary extended across the southern High Plains. Low level moisture was advecting northward across the region. && .SHORT TERM...(Today and tonight) ISSUED AT 1251 AM CST FRI JAN 10 2014 This morning: Immediate near term concern is fog. Issued a dense fog advisory earlier based off HRRR and WRF visibilities as well a trend in the observations. Winds have remained elevated as the warm sector has spread across SW Kansas early this morning. Will continue with the advisory as is and later shifts can cancel or trim counties as seen fit. Downslope/dry air advection is expected later today in the wake of a passing cold front, which should scour low level moisture out. Today: A synoptic trof ushering in the passage of said front will move across the region through the day. Mesoscale and global models have a hint of QPF across NW Kansas at the base of the 400 hPa PVU hook. Not overly impressive for my counties as isentropic downglide develops in earnest with the passage of the trof. Will go with ghost probability percentage precipitation points for now up north. Otherwise, Boise verification shows a bias in recent temperatures forecasts, and will trend with the GEM for now, which has been performing better recently. Low 40sF northwest to upper 40sF southeast. Tonight: Westerly to northwesterly flow at the surface and a dry northwesterly flow aloft will continue tonight. Continued dry air advection with resultant decreasing dewpoints and weaker winds favor cooler minimum temperatures through the overnight - 20sF. .LONG TERM...(Saturday through Thursday) ISSUED AT 320 AM CST FRI JAN 10 2014 No precipitation is anticipated for the days 2 through 7 period. No strong upper level feature will be crossing the plains, and a couple of fronts will pass through dry. Saturday will see an upper level trough over the Mississippi Valley, and the 500mb flow from the northwest across western Kansas. A broad ridge aloft will drift across the plains, bringing mostly sunny skies and warming temperatures this weekend. Saturday will see highs in the middle 50s, and then warming into the mid 50s to lower 60s on Sunday. The upper flow pattern will turn to zonal on Monday, bringing a few upper level clouds and just a slight cool down to temperatures. Monday`s highs will range in the lower 50s in central Kansas to near the mid 50s along the Oklahoma border. Tuesday will bring a cool down, with highs in the upper 40s north of I-70 to the lower 50s near Meade and Ashland. Then we will return to a down slope, northwesterly flow aloft Wednesday. A warm front should shoot northeastward through western Kansas Tuesday night, and bring maximum temperatures in the middle 50s for most locations in southwestern Kansas on Wednesday. Minimum temperatures throughout the Saturday through Friday period will average from the middle 20s to the middle 30s. Surface winds will generally be northwest 15 mph gusting 25 mph during most afternoons. The winds will die down in the evening, and be less than 10 mph during the night time periods. The only night that will be an exception to that will be Tuesday night behind the frontal passage, with north winds at 15 to 20 mph. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 1100 PM CST THU JAN 9 2014 Cigs will continue to decrease through the overnight in association with stratus and fog. VFR cigs expected by mid morning as drier air advects in the wake of a frontal passage. Southerly winds will veer northwesterly 10-20 kt. && .PRELIMINARY POINT TEMPS/POPS... DDC 46 25 55 30 / 0 0 0 0 GCK 44 26 56 29 / 0 0 0 0 EHA 45 25 58 33 / 0 0 0 0 LBL 45 23 58 31 / 0 0 0 0 HYS 45 25 53 29 / 10 0 0 0 P28 48 28 56 31 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY until 9 AM CST this morning FOR KSZ030-031- 043>046-063>066-076>081-087>090. && $$ SYNOPSIS...Sugden SHORT TERM...Sugden LONG TERM...Burke AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1256 AM MST FRI JAN 10 2014 .SHORT TERM...(THIS AFTERNOON THROUGH FRIDAY) ISSUED AT 106 PM MST THU JAN 9 2014 LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW A PROGRESSIVE ZONAL PATTERN IN PLACE ACROSS THE CONUS WITH A SPLIT TROUGH OVER THE WESTERN US. PV HEIGHT MINIMUM IS OVER SOUTHERN IDAHO WITH ENHANCEMENT AHEAD OF THIS FEATURE ON WV IMAGERY ACROSS WYOMING. THIS AFTERNOON...FOG HAS LIFTED OVER THE CWA...HOWEVER THERE CONTINUES TO BE SEVERAL AREAS OF LOW STRATUS LINGERING ACROSS THE REGION...WITH THE MOST EXTENSIVE AREA OVER CENTRAL KANSAS. WHILE SURFACE TROUGH HAS SHIFTED EAST AND ALL INDICATIONS BY SHORT RANGE GUIDANCE TEMPS HAVE MODIFIED ALOFT...WITH COLD POOL SHIFTING EAST. THERE HAS BEEN LESS OF A REFLECTION OF THE CHANGE IN AIR MASS WITH TEMPS SLOW TO RECOVER SO FAR. WILL LIKELY NEED TO KEEP AN EYE ON TRENDS...BUT I BUMPED EXPECTED HIGHS DOWN A LITTLE TO MATCH THE SLOWER RATE OF WARMING THIS AFTERNOON. TONIGHT-FRIDAY...AS UPPER TROUGH SHIFTS EAST TONIGHT BEST FORCING/MOISTURE WILL REMAIN WELL EAST OF THE CWA. BL MOISTURE WILL REMAIN HIGH HOWEVER OVER EASTERN LOCATIONS WHERE FOG/STRATUS HAVE BEEN SLOWER TO ERODE AND FURTHER FOG/STRATUS DEVELOPMENT IS LIKELY. AS THE UPPER LEVEL SYSTEM SHIFTS EAST ANY FOG THAT DOES DEVELOP SHOULD QUICKLY PUSH EAST AS GUSTY NW WINDS DRY OUT THE BL. WHILE FORCING WILL BE INCREASING AS NOSE OF H3 JET ON THE BACK SIDE OF THE UPPER LOW MOVES ACROSS OUR CWA LATE TONIGHT THROUGH FRIDAY...MOISTURE PROFILES CONTINUE TO BE UNIMPRESSIVE THROUGH MOST OF THESE PERIODS. 15-18Z MODEL SOUNDINGS ARE MORE IMPRESSIVE AND WOULD SUPPORT PRECIPITATION. I KEPT POP MENTION TO SLIGHT CHANCE STARTING AFTER 06Z TONIGHT IN THE NW AND OVERSPREADING MOST OF THE CWA THROUGH FRIDAY. ANY PRECIP SHOULD START OUT AS LIGHT SNOW MIXING WITH AND CHANGING TO RAIN DURING THE DAYTIME PERIOD. DUE TO THE QUICK NATURE OF THE SYSTEM AND GENERAL LACK OF MOISTURE AMOUNTS SHOULD BE VERY LIGHT. .LONG TERM...(MONDAY THROUGH NEXT FRIDAY) ISSUED AT 1253 AM MST FRI JAN 10 2014 THE LONG TERM PERIOD WILL BE QUIET UNDER THE INFLUENCE OF A RIDGE CENTERED OVER THE GREAT BASIN. A COUPLE OF FRONTAL PASSAGES ASSOCIATED WITH SHORTWAVE TROUGHS EMBEDDED IN THE NORTHWEST FLOW WILL RESULT IN BRIEF COOL DOWNS...BUT OVERALL TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE PERIOD. NO PRECIPITATION IS EXPECTED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1005 PM MST THU JAN 9 2014 KGLD...WITHIN THE PAST HOUR OR TWO WINDS HAVE BECOME MORE SOUTHERLY VS SOUTHWESTERLY WHICH HAS ALLOWED LOW LEVEL STRATUS/FOG AND MVFR CONDITIONS TO ADVANCE FURTHER WEST THEN PREVIOUSLY EXPECTED. THESE CONDITIONS EXPECTED THROUGH APPROXIMATELY 9-10Z BEFORE SOUTHWEST WINDS RE-ESTABLISH THEMSELVES AND PUSH IFR/LIFR CONDITIONS TO THE EAST AND THUS BRING VFR CONDITIONS BACK AND CONTINUE THROUGH THE REST OF THE TAF PERIOD. LIKE PREVIOUS DISCUSSION GUSTY NORTHWEST WINDS EXPECTED BY 11Z AND CONTINUE THROUGH 23Z BEFORE DECREASING AROUND 10KTS FROM THE WEST/NORTHWEST FROM 23Z-06Z. MAY SEE A SNOW SHOWER OR FLURRIES MOVE THROUGH IN THE 11Z-15Z TIMEFRAME AS WELL AS A WEATHER DISTURBANCE MOVES THROUGH. KMCK...MVFR VIS ONGOING WITH LIGHT SOUTHEAST WINDS. THESE CONDITIONS EXPECTED TO CONTINUE THROUGH 14Z BEFORE NORTHWEST WINDS OF 15-20KTS WITH HIGHER GUSTS MOVE IN...PUSHING MVFR AIRMASS OUT. HOWEVER...ANOTHER DISTURBANCE AND MVFR CIGS MOVE IN DURING THE 16Z-20Z TIMEFRAME BRINGING A RETURN TO MVFR CONDITIONS. BY 23Z VFR CONDITIONS EXPECTED THROUGH THE REST OF THE TAF PERIOD ALONG WITH WEST/NORTHWEST WINDS AROUND 11KTS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...024 AVIATION...99
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1251 AM CST Fri Jan 10 2014 ...Update to short term discussion... .SYNOPSIS... ISSUED AT 1020 PM CST THU JAN 9 2014 The 10.00Z 250 hPa map showed strong NNW flow across the Pacific Northwest with magnitudes in the 120-130 kt range. Downstream, SW to W flow continued across the rest of the United States with magnitudes in the 90-100 kt range. At 500 hPa, a trof was moving across the central and northern Rockies. The KDDC raob showed a veering/warm air advection pattern in the low levels ahead of the aforementioned synoptic trof. At the sfc, a frontal boundary extended across the southern High Plains. Low level moisture was advecting northward across the region. && .SHORT TERM...(Today and tonight) ISSUED AT 1251 AM CST FRI JAN 10 2014 This morning: Immediate near term concern is fog. Issued a dense fog advisory earlier based off HRRR and WRF visibilities as well a trend in the observations. Winds have remained elevated as the warm sector has spread across SW Kansas early this morning. Will continue with the advisory as is and later shifts can cancel or trim counties as seen fit. Downslope/dry air advection is expected later today in the wake of a passing cold front, which should scour low level moisture out. Today: A synoptic trof ushering in the passage of said front will move across the region through the day. Mesoscale and global models have a hint of QPF across NW Kansas at the base of the 400 hPa PVU hook. Not overly impressive for my counties as isentropic downglide develops in earnest with the passage of the trof. Will go with ghost probability percentage precipitation points for now up north. Otherwise, Boise verification shows a bias in recent temperatures forecasts, and will trend with the GEM for now, which has been performing better recently. Low 40sF northwest to upper 40sF southeast. Tonight: Westerly to northwesterly flow at the surface and a dry northwesterly flow aloft will continue tonight. Continued dry air advection with resultant decreasing dewpoints and weaker winds favor cooler minimum temperatures through the overnight - 20sF. .LONG TERM...(Friday night through Thursday) ISSUED AT 352 PM CST THU JAN 9 2014 Shortwave ridging will progress across the high plains Saturday as the next upper level system moves onshore into the western United States. Highs should reach into the 50s given the lee troughing and south to southwesterly surface winds. The system over the western USA will progress across the high plains on Sunday; but given the progressiveness of the system and lack of rich low to mid level moisture, precipitation is not expected. Fair weather can be expected Monday through Wednesday as northwesterly mid to upper level flow develops over the plains region. High temperatures will be in the 50s Monday ahead of a cold front, then back into the upper 40s to lower 50s Tuesday behind the weak front, and then up into the 50s by Wednesday as surface troughing and southwesterly winds return. The next progressive upper level system in northwesterly flow will progress across the plains region by Wednesday night and early Thursday. Progressive systems in January usually pass dry, and this should be no exception. Behind the associated weak cold front, high temperatures will fall back to the upper 40s to near 50F. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) ISSUED AT 1100 PM CST THU JAN 9 2014 Cigs will continue to decrease through the overnight in association with stratus and fog. VFR cigs expected by mid morning as drier air advects in the wake of a frontal passage. Southerly winds will veer northwesterly 10-20 kt. && .PRELIMINARY POINT TEMPS/POPS... DDC 46 25 55 30 / 0 0 0 0 GCK 44 26 56 29 / 0 0 0 0 EHA 45 25 58 33 / 0 0 0 0 LBL 45 23 58 31 / 0 0 0 0 HYS 45 25 53 29 / 10 0 0 0 P28 48 28 56 31 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY until 9 AM CST this morning FOR KSZ030-031- 043>046-063>066-076>081-087>090. && $$ SYNOPSIS...Sugden SHORT TERM...Sugden LONG TERM...Finch AVIATION...Sugden
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1005 PM MST THU JAN 9 2014 .SHORT TERM...(THIS AFTERNOON THROUGH FRIDAY) ISSUED AT 106 PM MST THU JAN 9 2014 LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOW A PROGRESSIVE ZONAL PATTERN IN PLACE ACROSS THE CONUS WITH A SPLIT TROUGH OVER THE WESTERN US. PV HEIGHT MINIMUM IS OVER SOUTHERN IDAHO WITH ENHANCEMENT AHEAD OF THIS FEATURE ON WV IMAGERY ACROSS WYOMING. THIS AFTERNOON...FOG HAS LIFTED OVER THE CWA...HOWEVER THERE CONTINUES TO BE SEVERAL AREAS OF LOW STRATUS LINGERING ACROSS THE REGION...WITH THE MOST EXTENSIVE AREA OVER CENTRAL KANSAS. WHILE SURFACE TROUGH HAS SHIFTED EAST AND ALL INDICATIONS BY SHORT RANGE GUIDANCE TEMPS HAVE MODIFIED ALOFT...WITH COLD POOL SHIFTING EAST. THERE HAS BEEN LESS OF A REFLECTION OF THE CHANGE IN AIR MASS WITH TEMPS SLOW TO RECOVER SO FAR. WILL LIKELY NEED TO KEEP AN EYE ON TRENDS...BUT I BUMPED EXPECTED HIGHS DOWN A LITTLE TO MATCH THE SLOWER RATE OF WARMING THIS AFTERNOON. TONIGHT-FRIDAY...AS UPPER TROUGH SHIFTS EAST TONIGHT BEST FORCING/MOISTURE WILL REMAIN WELL EAST OF THE CWA. BL MOISTURE WILL REMAIN HIGH HOWEVER OVER EASTERN LOCATIONS WHERE FOG/STRATUS HAVE BEEN SLOWER TO ERODE AND FURTHER FOG/STRATUS DEVELOPMENT IS LIKELY. AS THE UPPER LEVEL SYSTEM SHIFTS EAST ANY FOG THAT DOES DEVELOP SHOULD QUICKLY PUSH EAST AS GUSTY NW WINDS DRY OUT THE BL. WHILE FORCING WILL BE INCREASING AS NOSE OF H3 JET ON THE BACK SIDE OF THE UPPER LOW MOVES ACROSS OUR CWA LATE TONIGHT THROUGH FRIDAY...MOISTURE PROFILES CONTINUE TO BE UNIMPRESSIVE THROUGH MOST OF THESE PERIODS. 15-18Z MODEL SOUNDINGS ARE MORE IMPRESSIVE AND WOULD SUPPORT PRECIPITATION. I KEPT POP MENTION TO SLIGHT CHANCE STARTING AFTER 06Z TONIGHT IN THE NW AND OVERSPREADING MOST OF THE CWA THROUGH FRIDAY. ANY PRECIP SHOULD START OUT AS LIGHT SNOW MIXING WITH AND CHANGING TO RAIN DURING THE DAYTIME PERIOD. DUE TO THE QUICK NATURE OF THE SYSTEM AND GENERAL LACK OF MOISTURE AMOUNTS SHOULD BE VERY LIGHT. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 220 PM MST THU JAN 9 2014 FRIDAY NIGHT A STRONG 300MB JET STREAK WILL MOVE IN BEHIND THE EXITING TROUGH AXIS. AS THE JET STREAK MOVES IN THE LEFT EXIT OF THE JET STREAK WILL MOVE OVER THE AREA. WITH SATURATED MID LEVELS REMAINING BEHIND THE TROUGH AXIS AND A 500MB SHORT WAVE TROUGH ALSO MOVING OVER THE AREA...CANNOT COMPLETELY RULE OUT SOME LINGERING LIGHT SNOW DURING THE NIGHT. BEHIND THE 500MB SHORT WAVE TROUGH THE ENVIRONMENT WILL DRY OUT AND SUBSIDENCE WILL MOVE IN. SATURDAY AN UPPER LEVEL RIDGE WILL MOVE THROUGH DURING THE DAY AND THE ENVIRONMENT WILL CONTINUE TO DRY OUT. BEHIND THE RIDGE AXIS WARMER AIR WILL ADVECT OVER THE AREA ALLOWING TEMPERATURES TO WARM. SATURDAY NIGHT A SURFACE TROUGH WILL MOVE THROUGH THE AREA. DUE TO THE DRY ENVIRONMENT IN PLACE AM NOT ANTICIPATING ANYTHING MORE THAN HIGH CLOUDS TO ACCOMPANY THE TROUGH PASSAGE. FOR SUNDAY THROUGH THURSDAY WARMER AND WINDY WILL BE THE PRIMARY WEATHER THEME. AN UPPER LEVEL SHORT WAVE TROUGH WILL MOVE OVER THE AREA SUNDAY WHICH MAY BRING SOME MINIMAL CHANCES FOR RAINFALL TO PARTS OF THE AREA. HOWEVER MODELS ARE SUGGESTING A SPLIT UPPER LEVEL JET WHICH USUALLY IS NOT FAVORABLE FOR DEVELOPING PRECIP. OVER THE TRI-STATE AREA. BEHIND THE TROUGH THE UPPER LEVEL FLOW WILL REMAIN FROM THE NORTHWEST THROUGH THE PERIOD AS AN UPPER LEVEL RIDGE BUILDS OVER THE WESTERN CONUS. A COLD FRONT WILL MOVE THROUGH TUESDAY AND THURSDAY ALONG WITH AN UPPER LEVEL SHORT WAVE TROUGH. HOWEVER THE MAJORITY OF THE JET DYNAMICS WITH THE SHORT WAVE TROUGH WILL BE OVER THE GREAT LAKES. AS SUCH BELIEVE THE AREA WILL BE DRY WITH BOTH FRONTAL PASSAGES. WITH A STRONG NORTHWEST FLOW PATTERN OVER THE AREA THIS PERIOD WILL BE WINDY. HIGH TEMPERATURES FOR THE PERIOD WILL BE ABOVE NORMAL EXCEPT FOR TUESDAY AND THURSDAY WHEN A COLD FRONT MOVES THROUGH. LOW TEMPERATURES FOR THE PERIOD WILL BE NEAR NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1005 PM MST THU JAN 9 2014 KGLD...WITHIN THE PAST HOUR OR TWO WINDS HAVE BECOME MORE SOUTHERLY VS SOUTHWESTERLY WHICH HAS ALLOWED LOW LEVEL STRATUS/FOG AND MVFR CONDITIONS TO ADVANCE FURTHER WEST THEN PREVIOUSLY EXPECTED. THESE CONDITIONS EXPECTED THROUGH APPROXIMATELY 9-10Z BEFORE SOUTHWEST WINDS RE-ESTABLISH THEMSELVES AND PUSH IFR/LIFR CONDITIONS TO THE EAST AND THUS BRING VFR CONDITIONS BACK AND CONTINUE THROUGH THE REST OF THE TAF PERIOD. LIKE PREVIOUS DISCUSSION GUSTY NORTHWEST WINDS EXPECTED BY 11Z AND CONTINUE THROUGH 23Z BEFORE DECREASING AROUND 10KTS FROM THE WEST/NORTHWEST FROM 23Z-06Z. MAY SEE A SNOW SHOWER OR FLURRIES MOVE THROUGH IN THE 11Z-15Z TIMEFRAME AS WELL AS A WEATHER DISTURBANCE MOVES THROUGH. KMCK...MVFR VIS ONGOING WITH LIGHT SOUTHEAST WINDS. THESE CONDITIONS EXPECTED TO CONTINUE THROUGH 14Z BEFORE NORTHWEST WINDS OF 15-20KTS WITH HIGHER GUSTS MOVE IN...PUSHING MVFR AIRMASS OUT. HOWEVER...ANOTHER DISTURBANCE AND MVFR CIGS MOVE IN DURING THE 16Z-20Z TIMEFRAME BRINGING A RETURN TO MVFR CONDITIONS. BY 23Z VFR CONDITIONS EXPECTED THROUGH THE REST OF THE TAF PERIOD ALONG WITH WEST/NORTHWEST WINDS AROUND 11KTS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...JTL AVIATION...99
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
416 AM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE MOVES OFFSHORE TODAY AND TONIGHT AS A SERIES OF WEAK UPPER LEVEL TROUGHS TRACK ACROSS THE MID ATLANTIC REGION. A COLD FRONT APPROACHES FROM THE WEST SATURDAY AND PUSHES THROUGH THE REGION SATURDAY NIGHT EVENING. HIGH PRESSURE RETURNS FROM THE WEST LATER SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... THE LATEST SURFACE ANALYSIS INDICATES A ~1038MB SFC HIGH PRESSURE CENTERED OVER CAPE COD...WITH A SFC RIDGE AXIS EXTENDING SW ALONG THE PIEDMONT INTO NE GA. LATEST WATER VAPOR SHOWS NICE PV MAX MOVING FROM OH INTO WRN PA. THIS IS PUSHING CLOUDS ACROSS INTO THE NORTHERN SECTIONS OF THE CWA BUT ALL PRECIP WITH THIS HAS STAYED TO THE NORTH AND WEST OF THE AREA. ANOTHER AREA OF WARM ADVECTION IS BEGINNING TO DEVELOP TO THE SOUTHWEST OVER THE WRN CAROLINAS. THE HRRR AND RUC BOTH SHOW MOISTURE FROM THIS MOVING NORTH AND MERGING WITH THE NRN SYSTEM. THIS WILL BRING THE PRECIP INTO THE WRN SECTIONS NEAR SUNRISE. MOST MODELS AGREE THAT THE ONSET OCCURS BETWEEN 10Z AND 12Z. AS OF 06Z...CLOUDS HAVE OVERSPREAD MUCH OF THE LOCAL AREA. THIS HAS ALLOWED TEMPERATURES TO RISE A FEW DEGREES...WITH A MORE NOTABLE RISE FOR SE COASTAL LOCATIONS AS A COASTAL FRONT BEGINS TO INTRUDE. DEWPOINTS REMAIN IN THE LOW/MID 20S OVER THE NW PIEDMONT COUNTIES...AND THIS WILL COMPLICATE PRECIP TYPE AS MOISTURE ARRIVES TOWARD MORNING. MODEL THICKNESSES AND BUFKIT SOUNDINGS INDICATE THE POTENTIAL FOR A LIGHT MIX (MAINLY NW A LINE FROM DAN-OFP-BWI) TOWARD FRIDAY MORNING. BASED ON LATEST FORECAST SOUNDINGS...EXPECT LIGHT PRECIP TO BEGIN AS SLEET/IP...BEFORE TRANSITIONING QUICKLY TO FZRA. ANY QPF WILL BE VERY LIGHT (LESS THAN 0.10IN). HOWEVER...CONSIDERING THE TIMING OF ANY LGT PRECIP COINCIDING WITH THE EARLY PORTION OF THE MORNING RUSH...A SHORT DURATION FZRA ADVISORY WILL REMAIN IN AFFECT OVER THE PIEDMONT NW OF RIC METRO THROUGH 14Z. OF NOTE...MECKLENBURG AND LUNENBURG COUNTIES HAVE BEEN REMOVED FROM THE ADVISORY AS CURRENT OBSERVATIONAL DATA AND MODEL DATA DOES NOT SUPPORT THE POTENTIAL FOR EVEN MINOR ICING. POINTS FARTHER EAST...SUCH AS THE NORTHERN NECK AND INTERIOR LOWER MD EASTERN SHORE COULD EXPERIENCE SOME IP AT THE ONSET. HOWEVER...THERE IS LITTLE SUPPORT FOR ICING IN THESE LOCATIONS. ANY LINGERING FZRA THIS MORNING SHOULD TRANSITION TO RA AFTER 9 AM THIS MORNING. WARM/MOIST ADVECTION CONTINUES TODAY. THE SHORTWAVE TROUGH RESPONSIBLE FOR THE MORNING PRECIP LIFTS TO THE NE THIS MORNING. HOWEVER...ANOTHER MID-LEVEL WAVE LIFTS ACROSS THE REGION IN SSW FLOW ALOFT THIS AFTERNOON. THIS WILL BRING ANOTHER ROUND OF RA TO PRIMARILY CENTRAL PORTIONS OF THE AREA LATER THIS AFTERNOON. HIGH TEMPERATURES WILL VARY FROM AROUND 40 NW TODAY WITH A CAD WEDGE IN PLACE...TO NEAR 60 SE AS THE COASTAL FRONT MOVES INLAND. WEAK FLOW AND ABUNDANT MOISTURE BELOW 700MB WILL RESULT IN OVERCAST CONDITIONS THROUGHOUT TODAY. TEMPERATURES SHOULD FALL VERY LITTLE TONIGHT (AND LIKELY RISE TOWARD SATURDAY MORNING) AS THE SURFACE WARM FRONT LIFTS THROUGH THE AREA...RESULTING IN WIDESPREAD STRATUS AND OCCASIONAL -RA/DZ. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... THE TROUGH PRESENTLY DIGGING FROM THE INTERMOUNTAIN WEST TOWARD THE HIGH PLAINS PER GOES WATER VAPOR IMAGERY WILL CONTINUE TO AMPLIFY ACROSS THE CENTRAL CONUS TODAY. INCREASINGLY ZONAL FLOW OVER THE WESTERN US EVENTUALLY PUSHES THE TROUGH AXIS ACROSS THE APPALACHIANS BY SAT/SAT EVENING. ASIDE FROM SUBTLE TIMING DIFFERENCES...GEFS/SREF ENSEMBLE GUIDANCE ALONG WITH DETERMINISTIC ECMWF/GFS/NAM/CMC NOW DEMONSTRATE DECENT AGREEMENT WITH THIS SYSTEM. THERE IS A HIGH CONFIDENCE OF MEASURABLE RAIN IN THE SAT/SAT EVENING TIMEFRAME. DEEP MOISTURE THROUGH 300MB COMBINED WITH STRONG LIFT SHOULD PRODUCE MODERATE TO OCCASIONALLY HEAVY RA. HOWEVER...QPF SHOULD LARGELY AVG 0.75-1.00IN DUE TO THE QUICK MOTION OF THE SYSTEM. TEMPERATURES SHOULD BE VERY MILD AS THE SURFACE WARM FRONT LIFTS N OF THE LOCAL AREA AND 850MB TEMPERATURE SURGE TO 10-12C. FORECAST HIGHS FROM THE MID 60S TO AROUND 70 WILL BE MAINTAINED FOR MUCH OF THE FORECAST AREA. THERE IS STILL SOME UNCERTAINTY WITH RESPECT TO TEMPERATURE OVER NW PORTIONS...AS THERE IS A POSSIBILITY THAT A MODIFIED WEDGE AIRMASS MAY REMAIN LOCKED IN...WHICH COULD KEEP HIGHS IN THE 50S. BREEZY CONDITIONS DEVELOP FOR THE EASTERN THIRD OF THE AREA...WITH A S WIND OF 15-20MPH WITH GUSTS TO AROUND 30MPH. 10/03Z SREF PROBS CONTINUE TO INDICATE A 90% CHANCE OF 2M DEWPOINTS EXCEEDING 60F ACROSS S-CENTRAL/SE VA AND NE NC...AND 10/00Z NAM INDICATES STRONG UPRIGHT FRONTOGENESIS FROM THE SURFACE TO ~850MB...WHICH ENHANCES LOW-LEVEL VERTICAL ASCENT. THIS IS PROGGED TO OCCUR IN A SYNOPTIC ENVIRONMENT FEATURING 65-70KT 850-700MB LAYER AVG SSW WIND...50-60KT OF SW 0-6KM BULK SHEAR...AND 250-500 J/KG ML CAPE. GIVEN THE COMBINATION OF SYNOPTIC AND MESOSCALE FACTORS...THERE IS AN INCREASING PROB FOR A FORCED LINE OF CONVECTION (RARE BUT NOT UNPRECEDENTED FOR JAN) CAPABLE OF PRODUCING STRONG TO POTENTIALLY DAMAGING WIND GUSTS...MAINLY ACROSS S-CENTRAL/SE VA AND NE NC. BASED ON THE LATEST DATA...THE TIMING OF THE GREATEST THREAT WOULD BE FROM SAT AFTERNOON INTO EARLY EVENING. A TRANSITION DAY ON SUNDAY AS UPPER TROUGH PIVOTS OFFSHORE AND QUASI-ZONAL FLOW BRING A CLEARING AND STILL-MILD DAY. HIGHS GENERALLY IN THE 50S TO NEAR 60. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... STAYING CLOSE TO THE 12Z ECMWF FOR THE EXTENDED PERIOD. HI PRES WILL SLIDE OFF THE CST AND OUT TO SEA SUN NGT THRU MON...PROVIDING MSTLY CLEAR/PARTLY TO MOSTLY SUNNY CONDITIONS ACRS THE AREA. LATE MON NGT THRU TUE...THE LATEST ECMWF BRINGS A SRN STREAM LO AND A COLD FRONT TWD/AND ACRS THE AREA LATE MON NGT THRU TUE. AT THIS TIME...HAVE SLGT CHC (20) POPS THEN CHC (30) POPS OVR THE REGION. THE FRONT PUSHES OUT TO SEA TUE EVENG...BUT A SECONDARY BOUNDARY MAY CROSS THE AREA ON WED. HAVE KEPT A DRY FCST FOR WED AT THIS TIME. DRIER AND COOLER WNW FLO FILTERS IN FOR WED NGT THRU THU...AS HI PRES BLDS INTO AND OVR THE REGION. MIN TEMPS WILL RANGE THRU THE 30S MON MORNG...IN THE UPR 30S TO MID 40S TUE MORNG...IN THE 30S WED MORNG...AND IN THE MID 20S TO LWR 30S THU MORNG. MAX TEMPS WILL RANGE FM THE MID 50S TO LWR 60S MON...IN THE 50S TUE...IN THE MID 40S TO LWR 50S WED...AND IN THE 40S THU. && .AVIATION /09Z FRIDAY THROUGH TUESDAY/... -RA WILL BEGIN TO SPREAD INTO WESTERN PORTIONS OF THE FA AROUND DAYBREAK...AFFECTING KRIC BY 11Z-12Z. MVFR CONDITIONS WILL THEN OVERSPREAD THE ENTIRE AREA BY LATE MORNING...AND LIKELY CONTINUES INTO TONIGHT. BEST CHANCE FOR IFR CONDITIONS WILL BE AT KRIC. OUTLOOK...A MORE ORGANIZED FRONTAL SYSTEM APPROACHES THE REGION ON SATURDAY...WITH PERIODS OF RAIN AND WIDESPREAD MVFR/OCNL IFR CONDITIONS AND GUSTY WINDS. LOOK FOR DRY AND VFR CONDITIONS SUNDAY AND MONDAY THEN DETERIORATING CONDS ONCE AGAIN AROUND TUESDAY. && .MARINE... HIGH PRESSURE MOVES OFF THE NEW ENGLAND COAST TODAY...AS A TROF OF LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST. E WINDS 10 KT OR LESS THIS MORNING WILL BECOME SE 10-15 KT BY EVENING. SE WINDS WILL THEN INCREASE TO 15 TO 20 KT LATE TONIGHT BEFORE BECOME S AND INCREASING TO 15 TO 25 KT AND GUSTY FOR SAT...AS A WARM FRONT LIFTS NWRD THRU THE AREA...FOLLOWED BY THE APPROACH OF A COLD FRONT. HAVE ISSUED SCA`S BEGINNING EARLY SAT MORNING FOR ALL WATERS BASED ON GOOD AGREEMENT IN MODELS FOR GUSTY WINDS DURING SAT INTO SAT NIGHT... ALONG WITH SEAS BUILDING TO 5-9 FT. GALE FORCE WINDS ARE NOT EXPECTED ATTM EXCEPT POSSIBLY IN A NARROW BAND OF CONVECTION THAT MAY MOVE THRU WITH THE COLD FRONT LATE SAT. THIS CAN LIKELY BE HANDLED WITH SPECIAL MARINE WARNINGS AS OPPOSED TO A SHORT DURATION GALE WARNING. S-SW WINDS SAT INTO SAT EVE WILL VEER TO THE WNW AND REMAIN GUSTY BEHIND THE FRONT SAT NIGHT INTO SUN MORNING...THEN SETTLE DOWN AND BECOME SW LATE SUNDAY AS HIGH PRESSURE BUILDS IN. ANOTHER ROUND OF UNSETTLED CONDITIONS IS POSSIBLE BY TUESDAY. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ048- 049-060>064-067>069. MARINE...SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ630>634-650-652-654-656-658. SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ635>638. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ SHORT TERM...AJZ/MAM LONG TERM...TMG AVIATION...JDM MARINE...JDM
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
138 AM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE BUILDS OVER NEW ENGLAND OVERNIGHT AS A TROUGH OF LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST. HIGH PRESSURE MOVES OFFSHORE FRIDAY AS A WEAK UPPER LEVEL TROUGH PASSES ACROSS THE MID ATLANTIC. A COLD FRONT APPROACHES FROM THE WEST SATURDAY AND PUSHES THROUGH THE REGION SATURDAY NIGHT. HIGH PRESSURE RETURNS FROM THE WEST SUNDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE LATEST SURFACE ANALYSIS INDICATES A ~1038MB SFC HIGH PRESSURE CENTERED OVER CAPE COD...WITH A SFC RIDGE AXIS EXTENDING SW ALONG THE PIEDMONT INTO NE GA. LATEST WATER VAPOR SHOWS NICE PV MAX MOVING FROM OH INTO WRN PA. THIS IS PUSHING CLOUDS ACROSS INTO THE NORTHERN SECTIONS OF THE CWA BUT ALL PRECIP WITH THIS HAS STAYED TO THE NORTH AND WEST OF THE AREA. ANOTHER AREA OF WARM ADVECTION IS BEGINNING TO DEVELOP TO THE SOUTHWEST OVER THE WRN CAROLINAS. THE HRRR AND RUC BOTH SHOW MOISTURE FROM THIS MOVING NORTH AND MERGING WITH THE NRN SYSTEM. THIS WILL BRING THE PRECIP INTO THE WRN SECTIONS NEAR SUNRISE. MOST MODELS AGREE THAT THE ONSET OCCURS BETWEEN 10Z AND 12Z. AS OF 06Z...CLOUDS HAVE OVERSPREAD MUCH OF THE LOCAL AREA. THIS HAS ALLOWED TEMPERATURES TO RISE A FEW DEGREES...WITH A MORE NOTABLE RISE FOR SE COASTAL LOCATIONS AS A COASTAL FRONT BEGINS TO INTRUDE. DEWPOINTS REMAIN IN THE LOW/MID 20S OVER THE NW PIEDMONT COUNTIES...AND THIS WILL COMPLICATE PRECIP TYPE AS MOISTURE ARRIVES TOWARD MORNING. MODEL THICKNESSES AND BUFKIT SOUNDINGS INDICATE THE POTENTIAL FOR A LIGHT MIX (MAINLY NW A LINE FROM DAN-OFP-BWI) TOWARD FRIDAY MORNING. BASED ON LATEST FORECAST SOUNDINGS...EXPECT LIGHT PRECIP TO BEGIN AS SLEET/IP...BEFORE TRANSITIONING QUICKLY TO FZRA. ANY QPF WILL BE VERY LIGHT (LESS THAN 0.10IN). HOWEVER...CONSIDERING THE TIMING OF ANY LGT PRECIP COINCIDING WITH THE EARLY PORTION OF THE MORNING RUSH...A SHORT DURATION FZRA ADVISORY WILL REMAIN IN AFFECT OVER THE PIEDMONT NW OF RIC METRO THROUGH 14Z. OF NOTE...MECKLENBURG AND LUNENBURG COUNTIES HAVE BEEN REMOVED FROM THE ADVISORY AS CURRENT OBSERVATIONAL DATA AND MODEL DATA DOES NOT SUPPORT THE POTENTIAL FOR EVEN MINOR ICING. POINTS FARTHER EAST...SUCH AS THE NORTHERN NECK AND INTERIOR LOWER MD EASTERN SHORE COULD EXPERIENCE SOME IP AT THE ONSET. HOWEVER...THERE IS LITTLE SUPPORT FOR ICING IN THESE LOCATIONS. ANY LINGERING FZRA THIS MORNING SHOULD TRANSITION TO RA AFTER 9 AM THIS MORNING. WARM/MOIST ADVECTION CONTINUES TODAY. THE SHORTWAVE TROUGH RESPONSIBLE FOR THE MORNING PRECIP LIFTS TO THE NE THIS MORNING. HOWEVER...ANOTHER MID-LEVEL WAVE LIFTS ACROSS THE REGION IN SSW FLOW ALOFT THIS AFTERNOON. THIS WILL BRING ANOTHER ROUND OF RA TO PRIMARILY CENTRAL PORTIONS OF THE AREA LATER THIS AFTERNOON. HIGH TEMPERATURES WILL VARY FROM AROUND 40 NW TODAY WITH A CAD WEDGE IN PLACE...TO NEAR 60 SE AS THE COASTAL FRONT MOVES INLAND. WEAK FLOW AND ABUNDANT MOISTURE BELOW 700MB WILL RESULT IN OVERCAST CONDITIONS THROUGHOUT TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... TEMPERATURES SHOULD FALL VERY LITTLE TONIGHT AS THE SURFACE WARM FRONT LIFTS THROUGH THE AREA...RESULTING IN WIDESPREAD STRATUS. THE TROUGH PRESENTLY TRAVERSING THE INTERMOUNTAIN WEST THIS AFTN WILL PUSH ACROSS THE ROCKIES THROUGH TONIGHT...EVENTUALLY AMPLIFYING ACROSS THE CENTRAL CONUS ON FRI. SUBSEQUENT INCREASINGLY ZONAL FLOW OVER THE WESTERN US EVENTUALLY WILL EJECT THE TROUGH AXIS EAST ACROSS THE APPALACHIANS BY SAT/SAT EVENING. PLENTY OF SPREAD EXISTS AMONGST GEFS/SREF ENSEMBLE GUIDANCE AS WELL AS THE DETERMINISTIC MODELS WITH RESPECT TO TIMING. MODELS APPEAR IN BETTER AGREEMENT WITH QUICKLY SHUNTING THE WARM FRONT NORTHWARD SAT MORNING. THERE IS A HIGH CONFIDENCE OF MEASURABLE RAIN IN THE SAT/SAT EVENING TIME FRAME. DEEP MOISTURE THROUGH 300MB COMBINED WITH STRONG LIFT SHOULD PRODUCE MODERATE TO OCCASIONALLY HEAVY RAINFALL. HOWEVER...QPF SHOULD LARGELY BE 0.75-1.00IN DUE TO THE QUICK MOTION OF THE SYSTEM. TEMPERATURES SHOULD BE VERY MILD AS THE AFOREMENTIONED SURFACE WARM FRONT LIFTS N OF THE LOCAL AREA AND 850MB TEMPERATURE SURGE TO 10-12C. HIGHS HAVE BEEN NUDGED UPWARD SLIGHTLY ONCE AGAIN INTO THE MID 60S FAR NW...65-70 FOR CENTRAL AND EASTERN PORTIONS OF THE AREA. SREF PROBS CONTINUE TO INDICATE A 90% CHANCE OF 2M DEWPOINTS EXCEEDING 60F ACROSS S-CENTRAL/SE VA AND NE NC...AND 09/21Z NAM INDICATES STRONG UPRIGHT FRONTOGENESIS FROM THE SURFACE TO ~750MB (09/00Z ECMWF INDICATES THIS TO A LESSER EXTENT). THIS IS CONSIDERED A LOW PROB AT THIS TIME...BUT THERE IS A POTENTIAL FOR A FORCED LINE OF CONVECTION (RARE BUT NOT UNPRECEDENTED FOR JAN)...GIVEN STRONG SYNOPTIC FLOW (60-65KT 850-700MB LAYER AVG) COMBINED WITH THE AFOREMENTIONED ABUNDANT MOISTURE AND MESOSCALE FORCING. A TRANSITION DAY ON SUNDAY AS UPPER TROUGH PIVOTS OFFSHORE AND QUASI-ZONAL FLOW BRING A CLEARING AND STILL-MILD DAY. HIGHS GENERALLY IN THE 50S TO NEAR 60. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... STAYING CLOSE TO THE 12Z ECMWF FOR THE EXTENDED PERIOD. HI PRES WILL SLIDE OFF THE CST AND OUT TO SEA SUN NGT THRU MON...PROVIDING MSTLY CLEAR/PARTLY TO MOSTLY SUNNY CONDITIONS ACRS THE AREA. LATE MON NGT THRU TUE...THE LATEST ECMWF BRINGS A SRN STREAM LO AND A COLD FRONT TWD/AND ACRS THE AREA LATE MON NGT THRU TUE. AT THIS TIME...HAVE SLGT CHC (20) POPS THEN CHC (30) POPS OVR THE REGION. THE FRONT PUSHES OUT TO SEA TUE EVENG...BUT A SECONDARY BOUNDARY MAY CROSS THE AREA ON WED. HAVE KEPT A DRY FCST FOR WED AT THIS TIME. DRIER AND COOLER WNW FLO FILTERS IN FOR WED NGT THRU THU...AS HI PRES BLDS INTO AND OVR THE REGION. MIN TEMPS WILL RANGE THRU THE 30S MON MORNG...IN THE UPR 30S TO MID 40S TUE MORNG...IN THE 30S WED MORNG...AND IN THE MID 20S TO LWR 30S THU MORNG. MAX TEMPS WILL RANGE FM THE MID 50S TO LWR 60S MON...IN THE 50S TUE...IN THE MID 40S TO LWR 50S WED...AND IN THE 40S THU. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... A LIGHT EASTERLY FLOW WILL GRADUALLY INCREASE MOISTURE INTO THE AREA OVERNIGHT. CLOUDS BEGIN TO DEVELOP BELOW 10K FT AFTER MIDNIGHT AS AN INVERTED TROUGH/COASTAL FRONT DEVELOP TOWARD MORNING PROVIDING SOME LIFT. THE LOCATION OF THIS FRONT WILL AFFECT THE WIND DIRECTION (SE WINDS TO THE EAST OF THE FRONT) AND IMPACT THE CEILING HEIGHT ON FRIDAY. AS THIS FRONT DEVELOPS MID TO LATE MORNING...IT SHOULD SET UP WEST OF ALL THE TAF SITES EXCEPT RIC THROUGH MIDDAY. THUS HAVE IFR LATE MORNING AT RIC BUT MVFR OR BETTER AT THE REST. EVENTUALLY THE FRONT IS EXPECTED TO MOVE SLIGHTLY TO THE WEST OF RIC... IMPROVING CONDS THERE TO MVFR. USED NAM AND GFS SOUNDINGS AND POP GRIDS TO DETERMINE TIMING OF THE PCPN. HAVE IT BEGIN MID TO LATE MORNING BUT STAYING NORTH OF ECG. RAIN DIMINISHES AFT 18Z. THE POTENTIAL FOR FZRA OR PL (BRIEFLY AROUND 12Z FRIDAY) IS MAINLY WEST OF RIC AND ANY THAT OCCURS SHOULD HAVE LITTLE TO NO IMPACT. OUTLOOK...A MORE ORGANIZED FRONTAL SYSTEM APPROACHES THE REGION ON SATURDAY...WITH PERIODS OF RAIN AND WIDESPREAD MVFR/OCNL IFR CONDITIONS AND GUSTY WINDS. LOOK FOR DRY AND VFR SUNDAY AND MONDAY THEN DETERIORATING CONDS ONCE AGAIN AROUND TUESDAY. && .MARINE... DO NOT HAVE ANY HEADLINES IN THE SHORT TERM TNGT THRU FRI NIGHT. HI PRES WILL MOVE OFF THE NEW ENGLAND CST TNGT...AS A TROF OF LO PRES DEVELOPS ALNG THE CAROLINA CST. NE WINDS 10 KT OR LESS THIS EVENG...WILL BECOME ESE FOR TNGT THRU FRI. SE WINDS WILL THEN INCREASE TO NEAR 15 TO 20 KT LATE FRI NGT...THEN BECOME S AND INCREASE TO 15 TO 25 KT AND GUSTY FOR SAT...AS A WARM FRONT LIFTS NWRD THRU THE AREA...FOLLOWED BY THE APPROACH OF A COLD FRONT. SCA FLAGS WILL BE LIKELY FOR STRONG SOUTHERLY WINDS SAT AFTN/SAT NGT...WITH SEAS BUILDING TO 5-9 FT. WINDS BECOME WNW AND REMAIN RATHER STRONG BEHIND THE FRONT SAT NGT INTO SUN AFTN...THEN SETTLE DOWN AND BECOME SW SUN NGT...AS HI PRES BLDS IN THEN MOVES OFFSHR. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ048- 049-060>064-067>069. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...AJZ SHORT TERM...AJZ/MAM LONG TERM...TMG AVIATION...LSA MARINE...TMG
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1146 PM EST THU JAN 9 2014 .AVIATION... //DISCUSSION... SNOW CONTINUES TO LIFT THROUGH SOUTHEAST MICHIGAN OVERNIGHT AHEAD OF A WARM FRONT LIFTING NORTH. IT APPEARS THE SNOW WILL MISS MBS FOR THE MOST PART. ONCE THE SNOW LIFTS OUT OF THE AREA LIGHT SNOW AND FLURRIES WILL REMAIN BEFORE MID LEVEL MOISTURE GETS SCOURED OUT EARLY FRIDAY MORNING...BRINGING FREEZING DRIZZLE TO THE TAF SITES. THE POTENTIAL FOR FREEZING DRIZZLE IS HIGHER TOWARD SUNRISE IN THE DTW TO PTK CORRIDOR CLOSER TO THE SURFACE WARM FRONT BUT IT IS POSSIBLE AS FAR NORTH AS MBS JUST WITH LOWER CONFIDENCE THERE. CIGS/VSBYS ARE DIFFICULT TO GET A HANDLE ON AS THEY VARY FROM VFR TO IFR. OVERALL EXPECT CONDITIONS TO SETTLE INTO THE MVFR CATEGOR...EVENTUALLY FALLING TO IFR BEHIND THE WARM FRONT FRIDAY MORNING AND REMAINING THERE AS DRIZZLE AND RAIN IMPACT THE TAF SITES THROUGH FRIDAY EVENING. FOR DTW...A FEW HOURS OF FREEZING DRIZZLE IS EXPECTED TO BEGIN TOWARD SUNRISE AND LAST THROUGH LATE MORNING WHEN TEMPERATURE IS ON SCHEDULE TO RISE ABOVE FREEZING. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET THROUGH THE TAF PERIOD. * HIGH CONFIDENCE IN SNOW AS PRECIPITATION TYPE OVERNIGHT. * MEDIUM CONFIDENCE IN FREEZING DRIZZLE DEVELOPMENT TOWARD SUNRISE FRIDAY. && .PREV DISCUSSION...ISSUED 359 PM EST THU JAN 9 2014/ SHORT TERM... AFTERNOON AND TONIGHT AFTERNOON RADAR COMPOSITE AND SURFACE OBSERVATIONS INDICATE THE SNOW SHOWER PATTERN COMING TOGETHER WITH SOME GUSTO OVER NORTHERN INDIANA AND WESTERN OHIO. THE MID LEVEL SHORT WAVE SHOWN ON WATER VAPOR IMAGERY LOOKS QUITE DYNAMIC AND IS HELPING SHAPE UP THE WARM FRONT OVER THE OHIO VALLEY AT THE SURFACE AND ENHANCING ISENTROPIC LIFT TO THE NORTH OF THE FRONT INTO LOWER MICHIGAN. MODEL CROSS SECTIONS INDICATE THE SHORT WAVE INDUCED DCVA AND ISENTROPIC LIFT OCCURRING IN A LOW STABILITY ENVIRONMENT AND WITH A GENEROUS AMOUNT OF MOISTURE RESULTING IN THE STRONG VERTICAL MOTION RESPONSE. THE TEXTURE OF THE RADAR COMPOSITE EVEN SUGGESTS WEAK CONVECTIVE INSTABILITY ABOVE THE FRONTAL SURFACE, ROUGHLY IN THE 700-500 MB LAYER JUDGING FROM MODEL THETA-E PROFILES. THE LATEST RUNS OF THE NAM AND RAP HAVE A REASONABLE HANDLE ON THE EVOLUTION OF THE PATTERN AS THE WAVE SLIDES JUST SOUTH OF THE OHIO BORDER. THEY SHOW THE MOST INTENSE VERTICAL MOTION OCCURRING ROUGHLY ALONG AND SOUTH OF A LINE FROM HOWELL TO PORT HURON WITH A PEAK INTENSITY OCCURRING AROUND MID EVENING. THIS WILL CONSIST OF A GOOD COMBINATION OF LOW LEVEL ISENTROPIC LIFT AND MID LEVEL SHEARING DEFORMATION FUELED BY SPECIFIC HUMIDITY NEAR 3 G/KG. EXPECT THE RESULT TO BE WIDESPREAD LIGHT SNOW WITH IMBEDDED HEAVIER BURSTS ADDING UP TO ABOUT AN INCH OF ACCUMULATION AS FAR NORTH AS INTERSTATE 69. BOTH COVERAGE AND INTENSITY WILL BE LESS TOWARD THE TRI CITIES AND NORTHERN THUMB AND THEN WILL DIMINISH OVER THE SOUTH AFTER MIDNIGHT. STRONG MID LEVEL SUBSIDENCE TRAILING THE WAVE WILL THEN SET THE STAGE FOR FREEZING DRIZZLE POTENTIAL TOWARD SUNRISE. MODEL SOUNDINGS INDICATE SUBSIDENCE INDUCED MID LEVEL DRYING TAKING PLACE TOWARD 12Z WHICH WILL ELIMINATE ICE CRYSTAL NUCLEATION. THAT WILL LEAVE A FAVORABLE PROFILE FOR FREEZING DRIZZLE FORCED BY WIND SHEAR AND INSTABILITY AT THE TOP OF THE BOUNDARY LAYER/FRONTAL SLOPE. WHILE THE LARGE SCALE ENVIRONMENT IS SUPPORTIVE AND GROUND SURFACES ARE VERY COLD, UNCERTAINTY ON COVERAGE, DURATION, AND INTENSITY IS HIGH ENOUGH TO HOLD OFF ON HEADLINE ISSUANCE AT THIS POINT. OTHERWISE, THE STRONG NONDIURNAL TEMPERATURE TREND WILL HAVE MINS OCCURRING DURING EARLY EVENING FOLLOWED BY RISING TEMPS OVERNIGHT, BUT ONLY INTO THE LOWER AND MID 20S BY SUNRISE FRIDAY. LONG TERM...FRIDAY THROUGH SATURDAY NIGHT MAIN CONCERNS OVER THIS TIME PERIOD IS THE START TIME AND TYPE OF PRECIPITATION...ESPECIALLY FRIDAY AFTERNOON INTO EVENING BEFORE WARMER AIR WORKS UP INTO THE AREA. WEAK RIDGING AHEAD OF THE MAIN UPPER LEVEL TROUGH MOVING ACROSS THE AREA WILL ALLOW FOR A SLIGHT DOWNTURN IN THE PRECIP FRIDAY MORNING BEFORE MORE SUBSTANTIAL PRECIPITATION WORKS IN WITH THE NEXT LOW PRESSURE SYSTEM FRIDAY INTO SATURDAY. 120+ KNOT JET GETS GOING WITH THE LEFT ENTRANCE REGION MOVING OVER THE AREA. THIS JET THEN STRENGTHENS AS IT MOVES TO THE EAST OF THE AREA SATURDAY AFTERNOON. MODELS HAVE FINALLY COME INTO BETTER AGREEMENT ON THE TIMING AND DURATION OF THIS SYSTEM. AS THE LOW TRACKS NORTHEAST ACROSS WISCONSIN AND UPPER MICHIGAN...THIS WILL PULL A WARM FRONT UP THROUGH THE AREA FRIDAY BRINGING MOISTURE AND WARMER AIR TO SE MI. AS WITH THE CASE OF TRANSITIONING PRECIP TYPE THE BIGGEST CAVEAT WILL BE HOW LONG FREEZING DRIZZLE/RAIN LINGERS BEFORE THE WARMER AIR WORKS IN CHANGING PRECIP TO ALL RAIN. THIS TRANSITION DOES APPEAR TO BE OF SHORTER DURATION AS THE LOW LEVEL JET GETS GOING AND PUSHES IN THE WARMER AIR. SOUNDING PROFILES SHOW SATURATED LOW LEVELS WITH DRIER AIR IN THE MID LEVELS SUPPORTIVE OF DRIZZLE WITH THE ONSET OF PRECIP BEFORE MID LEVELS SATURATE. BETTER FORCING AND PRECIP CHANCES HOLD OFF UNTIL SATURDAY EVENING AS THE COLD FRONT APPROACHES. POPS INCREASE FROM 00Z TO 12Z ON SATURDAY WHICH COINCIDES WITH FAVORED ISENTROPIC ASCENT AHEAD OF THE COLD FRONT. PWAT VALUES REMAINED NEAR 3/4 OF AN INCH...WHICH IS GOOD FOR THIS TIME OF YEAR. WITH THE 12Z MODEL RUNS PUSHING THE COLD FRONT THROUGH A LITTLE FASTER...PRECIP AMOUNTS WERE LOWERED A TINY BIT. THE COLD FRONT IS EXPECTED TO EXIT THE AREA EARLY SATURDAY MORNING...BRINGING AN END TO THE HEAVIER PRECIP. SHOWERS WILL LINGER BEHIND THE FRONT BEFORE RIDGING MOVES BACK IN AND TEMPERATURES DROP BACK BELOW FREEZING. TEMPERATURES WERE DROPPED A LITTLE BIT TO TAKE INTO ACCOUNT THE SNOW COVER AND THE FASTER TIMING OF THE COLD FRONT THROUGH THE AREA SATURDAY EVENING. WAA WORKS IN AS STRONG SOUTHERLY FLOW INCREASES BEHIND THE WARM FRONT LATE FRIDAY BEFORE CAA TAKES OVER WITH THE EXITING COLD FRONT SATURDAY AFTERNOON. TEMPERATURES REMAIN ABOVE FREEZING AND STEADY FRIDAY INTO FRIDAY NIGHT BEFORE DROPPING BACK DOWN ONCE AGAIN. SURFACE RIDGING OVER THE GREAT LAKES REGION WILL KEEP SUNDAY MOSTLY DRY. SOUTHWESTERLY WINDS PICK UP ON SUNDAY WITH GUSTS UP TO 25 MPH DURING THE DAY. THERE IS SOME UNCERTAINTY AMONGST MODELS REGARDING PRECIPITATION CHANCES ON MONDAY. THEREFORE...HAVE ONLY KEPT A SLIGHT CHANCE IN THE FORECAST. HOWEVER...THERE LOOKS TO BE BETTER AGREEMENT THAT TUESDAY COULD BRING SOME PRECIP TO THE REGION. 850 MB TEMPS LOOK TO BE COLD ENOUGH TO SUPPORT ALL SNOW FOR PRECIP ON TUESDAY. HIGH TEMPERATURES WILL START OFF ABOVE NORMAL /FORECASTED HIGHS IN THE UPPER 30S/ ON MONDAY AND SLOWLY DECREASE THROUGHOUT THE REMAINDER OF THE WEEK DROPPING TO THE MID 20S BY THURSDAY. LOWS WILL ALSO START OFF ABOVE NORMAL /LOW 30S/ FOR MONDAY NIGHT AND STEADILY DROP INTO THE LOW TEENS /BELOW NORMAL/ BY THURSDAY NIGHT. MARINE... SOUTHERLY FLOW WILL CONTINUE TO INCREASE THROUGH TONIGHT AS HIGH PRESSURE SLIDES TOWARDS THE EAST COAST. LOW PRESSURE APPROACHING FROM THE PLAINS WILL THEN MAINTAIN SOUTHERLY FLOW THROUGH FRIDAY...WITH SPEEDS INCREASING FRIDAY NIGHT AS A WARM FRONT LIFTS UP THROUGH THE GREAT LAKES. SOUTH TO SOUTHEAST WINDS WILL BECOME GUSTY OVER LAKE HURON FRIDAY NIGHT AS THE LOW TRACKS UP THROUGH LAKE MICHIGAN. SUSTAINED SPEEDS LOOK TO RANGE BETWEEN 20 AND 28 KNOTS OVER MUCH OF THE LAKE...HOWEVER WARMER AIR FLOWING OVER THE LAKE SURFACE WILL KEEP STABILITY HIGH AND LIMIT WIND GUSTS TO BELOW GALE FORCE. COLDER AIR WILL POUR INTO THE REGION ON THE BACKSIDE OF THE SYSTEM ON SATURDAY. THE ARRIVAL OF THE COLDER AIR COMBINED WITH A TIGHT SURFACE PRESSURE GRADIENT AND STRONG WINDS ABOVE THE LAKE SURFACE MAY ALLOW GALE FORCE WINDS TO DEVELOP OVER THE CENTRAL PORTION OF LAKE HURON. A GALE WATCH IS NOW IN EFFECT OVER THE CENTRAL PORTION OF THE LAKE ON SATURDAY...INCLUDING SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT AUSTIN TO HARBOR BEACH. WIND SPEEDS WILL DECREASE SATURDAY NIGHT AND SUNDAY AS HIGH PRESSURE BUILDS BRIEFLY BACK OVER THE AREA. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WATCH...LHZ362-LHZ363-LHZ421-LHZ422-LHZ441-LHZ462...FROM 7 AM SATURDAY TO 7 PM SATURDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....KURIMSKI SHORT TERM...BT LONG TERM....SS/RK/HLO MARINE.......SS/HLO YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS BILLINGS MT
909 PM MST THU JAN 9 2014 .UPDATE... BROAD TROUGH OF LOW PRESSURE OVER THE AREA TONIGHT WITH WEAK SHORT WAVE ENERGY PUSHING ACROSS THE AREA. RADAR SHOWING SOME LIGHT RETURNS ACROSS SOUTHERN BIG HORN COUNTY AS WELL AS PORTIONS OF SOUTHEAST MONTANA IN NORTHWEST FLOW ALOFT. MOST OF THE LIFT FROM THE TROUGH WILL BE SLIDING SOUTH OF THE AREA AND LOWERED POPS FOR THE REMAINDER OF THE NIGHT OVER THE PLAINS TO ISOLATED TO LOW SCATTERED. TEMPERATURE FORECAST ON TRACK AND NO CHANGES MADE. PRESSURE FALLS OVER NORTHWEST MONTANA THIS EVENING WILL SPREAD INTO NORTH CENTRAL MONTANA LATER TONIGHT. THESE PRESSURE FALLS COMBINED WITH PRESSURE RISES CURRENTLY TAKING PLACE ACROSS NORTHWEST WYOMING WILL ALLOW GAP FLOW WINDS TO SET UP ALONG THE FOOTHILLS FROM NYE TO LIVINGSTON. WILL KEEP CURRENT ADVISORY GOING FOR NYE...BIG TIMBER AND LIVINGSTON TONIGHT. RICHMOND && .SHORT TERM...VALID FOR FRI AND SAT... MAIN FORECAST ISSUE REMAINS WIND. SHORTWAVE MOVING THROUGH THE REGION IS PRODUCING SOME RAIN/SNOW SHOWERS...MAINLY OVER OUR MTNS SO FAR...AND WITH MID LEVEL FLOW TURNING NW WE ARE SEEING SOME ECHOES FORM SE OF BILLINGS...AS WAS EXPECTED. STRONGEST ASCENT IS PUSHING WELL TO OUR SOUTH SO PCPN WILL BE GENERALLY LIGHT INTO THE EVENING...WITH MAYBE A COUPLE INCHES OF SNOW OVER THE BIG HORNS. FISHER CK SNOTEL ABOVE COOKE CITY PICKED UP 6 INCHES OF SNOW EARLIER TODAY. ATTENTION TURNS QUICKLY TO INCREASING PACIFIC JET AND ENERGY ALONG THE BC COAST. LEE SIDE PRESSURE FALLS SHOULD COMMENCE BY LATE EVENING AND OUR NEXT LIVINGSTON...BIG TIMBER...BEARTOOTH FOOTHILLS WIND EVENT WILL MATERIALIZE AS THE NIGHT WEARS ON. THIS WILL BE A MORE DYNAMIC EVENT WITH FASTER MID LEVEL FLOW...SO SHOULD BE A SOLID WIND ADVISORY WITH GUSTS OF 60-65 MPH LATE TONIGHT AND FRIDAY. CORE OF STRONGEST MID LEVEL FLOW...60 KTS PER THE GFS AND 70 KTS PER THE NAM...WILL PUSH INTO THE CRAZY MTN/WHEATLAND COUNTY AREA 12-18Z TOMORROW. LATEST RAP IS CONSISTENT WITH THESE SPEEDS AT 14Z TOMORROW. SUBSIDENCE FROM PAC SHORTWAVE WILL BE THE MECHANISM TO ALLOW STRONGER WINDS TO SFC...SO FEEL WE SHOULD SEE GUSTS OF 50-60 MPH FROM MELVILLE TO HARLOWTON TO A LITTLE SOUTH OF JUDITH GAP DURING THE DAY TOMORROW...THOUGH SFC AND MID LEVEL WINDS WILL NOT BE PERFECTLY LINKED UP. WILL ISSUE A HIGH WIND WARNING TO COVER THESE AREAS. SHOULD BE AT LEAST A MODEST DECREASE IN THE WIND BY FRIDAY NIGHT BEHIND PRESSURE RISES AND AS NEXT GAP EVENT GETS WARMED UP. FURTHER EAST ON FRIDAY...INCREASED MIXING WITH UP TO 40-45 KTS OF 850MB FLOW SHOULD YIELD STRONG GUSTS AS FAR EAST AS BILLINGS BY LATE MORNING...WHERE SFC GUSTS WILL REACH 40-50 MPH. AN OVERALL WINDY DAY ACROSS THE REGION TOMORROW. NEXT PERIOD OF STRONG WINDS BEGINS EARLY SATURDAY AND WILL KEEP HIGH WIND WATCHES INTACT ACROSS OUR WEST FROM SAT-MON. WITH 700MB WINDS TO 80 KTS AND A TIGHTER SFC GRADIENT THERE SHOULD BE 70+ MPH GUSTS AT THE GAP LOCATIONS...WITH A BIT LESS ELSEWHERE ACROSS OUR WEST. HAVE ATTEMPTED TO FIND A TIME WHEN MOUNTAIN WAVE ACTIVITY COULD BE A THREAT...AND THINK SATURDAY IS A RISK. NAM MAY BE A BIT OVERDONE BUT SHOWS A REGION OF NEAR 90 KT OF MTN TOP WIND ALONG THE BEARTOOTH FRONT BY 18Z SATURDAY. GFS IS A BIT WEAKER AND LATER WITH THE WIND POTENTIAL...BUT BOTH MODELS SUGGEST A MID LEVEL SHORTWAVE AND POTENTIAL FOR ENHANCED DOWNWARD MOTION IN THE LEE OF THE MTNS SOMETIME IN THE MIDDAY TO EVENING TIME PERIOD ON SATURDAY...WITH THE PREFRONTAL HOURS BEING MOST FAVORED FOR THIS TO OCCUR. COLD ADVECTION AND DESTABILIZING WILL REDUCE THE MTN WAVE THREAT LATER IN THE DAY ON SATURDAY. HAVE OPTED TO ISSUE A HIGH WIND WATCH FOR THE RED LODGE FOOTHILLS TO COVER THIS. NO DOUBT THE WINDS WILL BE SCREAMING ON THE MOUNTAINS ABOVE RED LODGE...SO OUTDOOR RECREATIONISTS TAKE NOTE. OTHERWISE...MOIST PACIFIC FLOW WILL BRING ADDITIONAL PERIODS OF OROGRAPHIC SNOWFALL TO THE WEST SLOPES OF THE BEARTOOTH ABSAROKAS THROUGH SATURDAY NIGHT...WITH A STEEPENING OF LAPSE RATES LATE SAT AND SAT NIGHT BEING THE EXPECTED TIME PERIOD OF HEAVIEST SNOWFALL. WILL KEEP POPS HIGH AND SNOW AMOUNTS SPREAD OVER THE NEXT FEW PERIODS. ACCUMS SHOULD ADD UP TO EXCEED A FOOT OVER THE NEXT 2-3 DAYS. TEMPS WILL REMAIN MILD OVER THE NEXT COUPLE DAYS. WARMEST AIRMASS WILL EXIST ON SATURDAY WITH MODELS SHOWING 850MB TEMPS TO AROUND +10C WITHIN THERMAL SFC TROF. WIND SHIFT MAY OCCUR TOO LATE FOR BILLINGS TO MAXIMIZE ITS TEMPERATURE POTENTIAL ON SATURDAY...PER USUAL INFLUENCE FROM THE CLARKS FORK/SW WINDS...BUT IF WINDS DO SHIFT WESTERLY BEFORE 00Z WE COULD SEE TEMPS INTO THE 50S. SNOW COVER WILL ALSO BE A FACTOR. AS IT STANDS...FEEL SOME AREAS WILL SEE 50+ DEGREE HIGHS. JKL .LONG TERM...VALID FOR SUN...MON...TUE...WED...THU... PROGRESSIVE NORTHWESTERLY FLOW WILL PREVAIL IN THE EXTENDED FORECAST...PRODUCING PERIODS OF STRONG WINDS ACROSS THE AREA. PICKING UP ON SUNDAY...SHORTWAVE OVERHEAD WILL PUSH EAST DURING THE DAY AND SURFACE HIGH WILL SKIM ACROSS EASTERN MONTANA. TEMPERATURES WILL BE COOLER BEHIND THE COLD FRONT ON SUNDAY...ESPECIALLY FOR EASTERN COUNTIES. SUNDAY WILL ALSO BE WINDY ACROSS THE AREA WITH COLD ADVECTION AND SUBSIDENCE HELPING TO PUSH 45 TO 50 KTS OF 850 HPA AND 700 HPA WIND TOWARD THE SURFACE. A STRONG PACIFIC JET STREAK MOVES INTO THE FORECAST AREA ON MONDAY...ACCOMPANYING THIS SYSTEM ARE VERY STRONG 850 AND 700 HPA WINDS. MODEL RUNS REMAIN CONSISTENT WITH 60 TO 90 KNOTS OF WIND CONCENTRATED AROUND 850MB MOVING ACROSS THE AREA THROUGH MONDAY AFTERNOON. WITH THIS MAGNITUDE OF WIND...EXPECT A STRONG MIXED WIND EVENT FOR LIVINGSTON...BIG TIMBER AND UP TO HARLOWTON. WINDS WILL ALSO BE STRONG ALL ACROSS THE PLAINS...AND WILL CONTINUE TO MONITOR THE TRENDS FOR ANY POTENTIAL WIND HIGHLIGHTS THAT MIGHT BE NEEDED FOR THIS PERIOD. MODELS HAVE ALSO BEEN CONSISTENT WITH DEVELOPING A BAND OF FRONTOGENESIS ACROSS EASTERN MONTANA WHICH WOULD RESULT IN SOME LIGHT SNOWFALL THERE. HAVE INCREASED POPS SLIGHTLY ACROSS EASTERN MONTANA TO ADDRESS THIS CONCERN. MODELS WANT TO KEEP PLENTY OF WIND AROUND ON TUESDAY...ALTHOUGH A MORE MODEST 50 KTS OR SO AT 850 MB. THUS THE WINDY PERIOD WILL CONTINUE ACROSS THE AREA...ALTHOUGH NOT QUITE AS WINDY AS MONDAY MAY BE. TEMPERATURES WILL BE MILD THROUGH THIS PERIOD AS DOWNSLOPE WINDS WILL KEEP TEMPERATURES ABOVE SEASONAL VALUES. MOUNTAIN SNOW WILL CONTINUE SUNDAY THROUGH TUESDAY AS MOIST PACIFIC FLOW CONTINUES. HOWEVER...THE MOIST FLOW MAY START TO SUBSIDE BY MIDWEEK...ENDING THE CHANCE OF SNOW SHOWERS THERE. CHURCH && .AVIATION... VFR CONDITIONS ARE EXPECTED TO PREVAIL OVERNIGHT AND EARLY FRIDAY. WINDS WILL INCREASE OVERNIGHT NEAR KLVM AND IN THE NEARBY FOOTHILLS...WITH GUSTS 50 TO 55 KTS POSSIBLE BY EARLY FRIDAY MORNING. CHURCH/AAG && .PRELIMINARY POINT TEMP/POPS... FRI SAT SUN MON TUE WED THU ----------------------------------------------------------- BIL 029/042 030/048 034/043 034/046 032/044 029/044 027/038 12/J 11/N 21/N 02/W 31/N 11/N 12/W LVM 031/040 033/049 032/040 034/043 031/043 029/042 030/034 23/W 22/W 32/W 22/W 21/N 11/N 22/W HDN 018/040 021/047 027/040 028/042 028/039 024/041 020/033 22/W 12/J 22/W 13/W 31/N 11/N 12/J MLS 019/036 020/040 028/035 025/038 023/036 022/038 019/032 22/J 12/W 32/J 14/J 32/J 11/N 12/J 4BQ 020/038 020/045 029/036 026/041 026/038 022/042 021/032 33/J 11/B 32/J 14/J 32/J 11/N 11/N BHK 021/037 020/040 029/032 021/038 023/035 018/039 019/031 22/J 11/B 32/J 13/J 22/J 11/N 11/N SHR 017/041 021/048 027/038 023/041 025/042 021/044 020/034 42/W 00/N 23/W 12/J 31/N 11/U 12/J && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...HIGH WIND WARNING IN EFFECT FROM 5 AM FRIDAY TO MIDNIGHT MST FRIDAY NIGHT FOR ZONES 28-63. HIGH WIND WATCH IN EFFECT FROM LATE FRIDAY NIGHT THROUGH MONDAY AFTERNOON FOR ZONES 28-41-63-65-66. WIND ADVISORY IN EFFECT UNTIL MIDNIGHT MST FRIDAY NIGHT FOR ZONES 41-65-66. HIGH WIND WATCH IN EFFECT FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR ZONE 56. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
340 AM CST FRI JAN 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 338 AM CST FRI JAN 10 2014 THE RAP HAS ANALYZED A H500 MB SHORT WAVE ACROSS ERN WYOMING THIS MORNING. THE PV15 ANOMALY EXTENDS FROM KCYS SOUTH THROUGH KDEN. IF THE RAP AND THE OTHER MODELS ARE CORRECT THEN SCATTERED SNOW SHOWERS SHOULD DEVELOP ACROSS NW NEB IN A FEW HOURS AND MOVE SOUTHEAST THROUGH SWRN AND SCNTL NEB. THE ONGOING RADAR RETURNS ACROSS NERN COLO ARE RAIN AND THE SNOW SHOWERS SHOULD DEVELOP ONCE THE THERMAL RIDGE ACROSS SWRN NEB MOVES EAST LATER THIS MORNING. OTHERWISE...THE ARCTIC DRAPE WILL MOVE EAST OF THE FCST AREA IN A FEW HOURS AHEAD THE SHORT WAVE AND ALL OF THIS WEATHER SHOULD EXIT THE FCST AREA TO THE EAST BY 21Z PROVIDING FOR A PARTLY SUNNY AFTERNOON WITH HIGHS IN THE UPPER 30S TO MID 40S. FOR TONIGHT...A WEAK COLD FRONT WILL BE PRESSING INTO NRN NEBRASKA TOWARD MORNING. THERE IS VERY LITTLE THERMAL RIDGING AHEAD OF THE FRONT AND H850 WINDS INCREASE FROM 25 TO 35 KT FRIDAY EVENING TO 40 TO 50 KT BY SATURDAY MORNING. ALL OF THIS SUGGESTS...GIVEN THE GENERALLY CLEAR SKIES TONIGHT...LOWS IN THE 20S MOST AREAS WITH TEENS IN THE PLATTE VALLEY AND CUSTER COUNTY. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 338 AM CST FRI JAN 10 2014 LITTLE CHANGE TO THE OVERALL PATTERN WITH A RIDGE IN THE WEST AND A TROUGH IN THE EAST...AND NORTHWEST FLOW ACROSS THE HIGH PLAINS. SEVERAL WEAK TROUGHS/CLIPPERS WILL PUSH ACROSS THE PLAINS...WITH A SLIGHT WARM UP AHEAD OF THE SYSTEM...AND A SLIGHT COOL DOWN WITH AN INCREASE OF CLOUDS WITH EACH TROUGH. WARM AIR ARRIVES FOR SATURDAY AHEAD OF THE NEXT TROUGH HIGHS NEARING THE MID 50S FOR THE SW AS 850 MB TEMPS PUSH TO AROUND 10 C. COOLER OVER N CENTRAL...MID 40S WITH 850 MB TEMPS CLOSER TO ZERO. SATURDAY NIGHT INTO SUNDAY THE TROUGH WILL CROSS THE CWA. MIXING ALONG AHEAD OF THE TROUGH WILL PUSH TEMPS BACK TO AROUND 50...WITH THE NW HOLDING CLOSER TO 40. THERE IS A CHANCE FOR SOME VERY LIGHT PRECIP /FLURRIES OR SPRINKLES/ ALTHOUGH LOW CONFIDENCE. MODELS HAVE SEVERAL MARGINAL POSITIVES TO LIGHT PRECIP...HOWEVER THEY ARE NOT OVERLAPPING. THE NW ZONES HAS THE STEEPEST LAPSE RATES HOWEVER THE RIGHT ENTRANCE TO A JET STREAK FAVORS THE SW. LL MOISTURE IS LIMITED AND MODELS VARY WITH POCKETS OF LOWER CONDENSATION DEFICITS...LESS THAN 20 MB. BY SUNDAY EVENING TROUGH AXIS IS EAST AND ANY LIGHT PRECIP WILL HAVE ENDED. MONDAY THE RIDGE RETURNS LATE IN THE DAY...AND HIGHS SHOULD REBOUND LATE TO AROUND 50 SW TO MID 50S N. BY MONDAY NIGHT A WEAK UPPER LEVEL DISTURBANCE TO RIDE THE NW FLOW. BETTER ENERGY IS ACROSS THE NORTHERN PLAINS...HOWEVER MAY GET SOME LIGHT SNOW ACROSS THE NW...WHERE MODELS HAVE A LITTLE UPPER LEVEL SUPPORT FROM THE LEFT EXIT REGION OF THE NEXT JET STREAK. THIS WILL WEAK SYSTEM WILL QUICKLY PASS TO THE EAST ON TUESDAY...ALTHOUGH SOME LINGERING CLOUDS EARLY ON IN THE DAY MAY LIMIT HEATING AND FOLLOWED SLIGHT COOL DOWN FROM THE DAY BEFORE...PER GUIDANCE. AS SYSTEM DIGITS ACROSS THE GREAT LAKES REGION/MID ATLANTIC FOR WEDNESDAY...RIDGE EXPANDS ACROSS THE WEST. MODELS IN GOOD AGREEMENT WITH ANOTHER SURGE OF WARMER AIR ACROSS THE HIGH PLAINS. HIGHS ONCE AGAIN INTO THE MID AND UPPER 50S FOR SW NEB AND UPPER 40S ELSEWHERE. THIS WARM AIR WILL BE AHEAD OF THE NEXT CLIPPER WHICH SHOULD ARRIVE WED NIGHT. THIS WILL BRING ANOTHER COOL DOWN FOR THURSDAY. ONE COMMON THEME THROUGH THE END OF THE WEEKEND INTO NEXT WEEK WILL BE BREEZY TO WINDY CONDITIONS. FAST MOVING SYSTEMS ARE STEERED BY SWIFT WINDS ALOFT AND WITH HIGHS ABOVE SEASONAL AVERAGES...GOOD MIXING WILL TAP INTO THE STRONGER WINDS. DAY TIME SFC WINDS OF 15 TO 30 MPH...WITH HIGHER GUSTS...CAN BE EXPECTED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1134 PM CST THU JAN 9 2014 OR THE REST OF TONIGHT...EXPECT IFR CIGS AT THE KLBF TERMINAL THROUGH 10Z FRIDAY. WINDS WILL SHIFT TO THE SOUTHWEST AROUND THIS TIME...WHICH WILL ALLOW CIGS TO INCREASE TO 6000 FT AGL. TOWARD SUNRISE FRIDAY...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL APPROACH WESTERN AND NORTH CENTRAL NEBRASKA. THIS WILL LEAD TO LOWERING CIGS AND AN INCREASED THREAT FOR SNOW FRIDAY MORNING. AT THIS TIME...THE THREAT FOR SNOW IS GREATEST ACROSS PORTIONS OF SOUTHWESTERN NEBRASKA. SNOW MAY IMPACT THE KLBF TERMINAL DURING THE 16Z TO 20Z TIME FRAME FRIDAY MORNING. VISBYS MAY DROP DOWN TO 1SM WITH OVERCAST CIGS DOWN TO 1000 FT AGL. FOR THE KVTN TERMINAL...THE THREAT FOR SNOW WILL BE FROM 14Z TO 18Z FRIDAY WITH VISBYS POSSIBLY DOWN TO 2SM. CIGS AT THE KVTN TERMINAL WILL RANGE FROM 1000 TO 1500 FT AGL FRIDAY MORNING INTO EARLY FRIDAY AFTERNOON. FOR BOTH TERMINALS...CIGS WILL INCREASE TO VFR AFTER 22Z FRIDAY. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...CLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1056 PM CST THU JAN 9 2014 .UPDATE... ISSUED AT 1010 PM CST THU JAN 9 2014 UPDATED THE FORECAST FOR TONIGHT INTO FRIDAY TO INCREASE TEMPERATURE AND DEWPOINT BY ROUGHLY 3 DEGREES OR SO ACROSS THE BOARD AS SKY COVER AND WARM AIR ADVECTION ENSURE THAT COOLING WILL BE TEMPERED. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 306 PM CST THU JAN 9 2014 FOCUS IS ON POTENTIAL FOR LIGHT PRECIPITATION AS A SHORTWAVE TROUGH CROSSES THE CENTRAL PLAINS. WATER VAPOR IMAGERY INDICATED A PROGRESSIVE PATTERN IN THE WESTERLIES WITH A SHORTWAVE TROUGH DIGGING OVER THE ROCKIES EARLY THIS AFTERNOON. STRATUS AND SNOW COVER HAS IMPACTED TEMPERATURES TODAY...WITH THE STRATUS SLOW TO ERODE ACROSS OUR NORTHWEST ZONES...WHILE A NEW AREA OF STRATUS IS ADVECTING NORTHWARD THROUGH KS EARLY THIS AFTN. TEMPS HAVE MANAGED TO REACH THE MID 20S TO THE MID 30S SO FAR WITH A FEW MORE HOURS OF INSOLATION LEFT. FOR TONIGHT...SOUTHERLY LLVL FLOW INCREASES AHEAD OF THE TROUGH EMERGING ONTO THE HIGH PLAINS. STRATUS WILL CONTINUE TO ADVECT TO THE NORTH AND EAST AND SIMILAR TO THIS MORNING WE ARE LOOKING AT THE POTENTIAL FOR FOG DEVELOPMENT. WINDS LOOK TO REMAIN STEADY ENOUGH TO LIMIT DENSE FOG POTENTIAL BUT WILL NEED TO MONITOR AS THE RAP AND HRRR INDICATE SOME LOCATIONS COULD SEE DENSE FOG. AHEAD OF THE APPROACHING TROUGH...ISENTROPIC LIFT INCREASES AS INDICATED ON THE 295K SURFACE...PRIMARILY ORIENTED ACROSS OUR SOUTHEAST ZONES AND THE LIFT OVER THE LLVL MOISTURE COULD LEAD TO FREEZING DRIZZLE TOWARD MORNING AND THIS REMAINS IN THE FORECAST. ALSO ACROSS OUR WESTERN ZONES...HAVE INTRODUCED LOW POPS TOWARD DAYBREAK FRIDAY AS THE MID LEVEL TROUGH REACHES THIS AREA AND FORECAST SOUNDINGS FROM THE RAP INITIALLY INDICATE THE POTENTIAL FOR FREEZING DRIZZLE...THEN SATURATE TO MORE OF A IP/SN SOUNDING. HAVE MENTIONED ZL/IP FOR NOW WITH PCPN TYPE TRANSITIONING TO R/S DURING THE DAY FRIDAY. THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY ON HOW MUCH PCPN WILL BE AROUND DURING THE DAY ON FRIDAY WITH THE NAM REMAINING THE DRIEST AMONGST THE MODELS. THE SURFACE COLD FRONT SWEEPS EASTWARD FRIDAY MORNING...AND THE MID LEVEL TROUGH EXTENDS ACROSS OUR CENTRAL CWA AROUND MIDDAY BEFORE TRANSLATING EASTWARD DURING THE AFTERNOON. MID LEVEL MOISTURE INCREASES AS THE TROUGH MOVES IN AND A NARROW BAND OF MID LEVEL FRONTOGENESIS/LIFT MOVE ACROSS FM LATE MORNING INTO EARLY AFTERNOON...MORE ALIGNED ACROSS THE EASTERN HALF OF OUR CWA. HAVE INCREASED POPS DURING THIS TIME FRAME AS SPC WRF...GFS...ECMWF AND EVEN THE GEM INDICATE THE POTENTIAL FOR BANDED PCPN. FORECAST SOUNDINGS INDICATE THE POSSIBILITY OF A QUICK SHOT OF SNOW INITIALLY THEN DRY OUT/WARM BEHIND THE TROUGH AND HAVE MAINTAINED A SIMPLE RAIN/SNOW MIX FOR PCPN TYPE ATTM. WITH A WARMING TEMP PROFILE...GENERALLY DO NOT EXPECT MUCH IN THE WAY OF ACCUMULATION BUT WOULD NOT BE SURPRISED TO SEE MINOR AMOUNTS...GENERALLY UNDER ONE HALF OF AN INCH. THE TROUGH AXIS SHIFTS EASTWARD BY FRIDAY EVENING WITH CONDITIONS DRYING OUT/CLOUDS DECREASING IN SUBSIDENCE BEHIND THE DEPARTING SYSTEM. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 306 PM CST THU JAN 9 2014 OVERALL...THE LONG TERM PERIOD LOOKS TO BE MOSTLY DRY. BY FRIDAY NIGHT...THE MAIN TROUGH AXIS AND SURFACE LOW PRESSURE SYSTEM HAVE SHIFTED TO THE EAST OF THE PLAINS...WHILE AN UPPER LEVEL RIDGE AXIS SLOWLY BEGINS TO SHIFT ACROSS THE ROCKIES. WITH THIS RIDGE...AND A DEVELOPING LEE SURFACE TROUGH...SOUTHWEST WINDS WILL HELP BRING WARMER AIR TO THE PLAINS FOR SATURDAY. WENT A BIT ABOVE GUIDANCE FOR SATURDAY...WITH MOSTLY SUNNY SKIES AND SOUTHWEST WINDS...SEE NO REASON WHY WE CANNOT REACH THE UPPER 40S TO EVEN NEAR 50. BY SUNDAY...A WEAK UPPER LEVEL DISTURBANCE SHIFTS ACROSS THE PLAINS HELPING TO BREAK DOWN THE RIDGE. AS THE MAIN SURFACE LOW REMAINS WELL TO THE NORTH OF THE REGION...AN ASSOCIATED COLD FRONT WILL PASS THROUGH THE PLAINS SUNDAY. AT THIS POINT...WILL NOT REINTRODUCE POPS TO THE FORECAST AS THE SURFACE LOW REMAINS WELL TO THE NORTH. THAT BEING SAID...CANNOT RULE OUT A FEW SPRINKLES OR FLURRIES DURING THE DAY AND NIGHT ON SUNDAY. THE WAVE DEEPENS ACROSS THE PLAINS BY MONDAY...BRINGING COOLER 850 MB TEMPERATURES INTO THE OUTLOOK AREA. PERHAPS MONDAY MIGHT NEED TO BE A TAD COOLER THAN FORECAST BUT STILL CURRENTLY EXPECTING MID 40S FOR HIGHS. THROUGH THE REST OF THE LONG TERM...NUMEROUS WAVES CONTINUES TO DIVE SOUTH AND SKIRT ALONG THE PLAINS. HOWEVER...NONE OF THEM SUGGEST ANYTHING IN THE WAY OF PRECIPITATION OR A LONG LASTING COLD SPELL. IN FACT...RIDGING REBOUNDS ACROSS THE AREA BY WEDNESDAY BRINGING TEMPERATURES BACK UP TO NEAR 50. TOWARDS THURSDAY...YET ANOTHER UPPER LEVEL WAVE/CLOSED LOW WILL SHIFT THROUGH THE GREAT LAKES REGION DRAGGING A COLD FRONT ACROSS THE AREA. && .AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1054 PM CST THU JAN 9 2014 STRATUS WILL CONTINUE DO DESCEND OVERNIGHT WITH LOWERING VISIBILITY. MODELS ARE STILL NOT INITIALIZING WELL...SO GOING WITH BEST GUESS. FOLLOWED MORE CLOSELY TO NAM MOS. FREEZING DRIZZLE SHOULD REMAIN SOUTH OF THE TERMINAL OVERNIGHT. COULD GET SOME RAIN/SNOW AS A TROUGH APPROACHES. WHEN THE WIND SWITCHES TO THE WEST/NORTHWEST BEHIND THE TROUGH...VISIBILITY AND CEILING WILL IMPROVE. CEILING SHOULD SCATTER BY FRIDAY EVENING AS THE TROUGH CONTINUES TO DEPART. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HEINLEIN SHORT TERM...FAY LONG TERM...SALTZMAN AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1012 PM CST THU JAN 9 2014 .UPDATE... ISSUED AT 1010 PM CST THU JAN 9 2014 UPDATED THE FORECAST FOR TONIGHT INTO FRIDAY TO INCREASE TEMPERATURE AND DEWPOINT BY ROUGHLY 3 DEGREES OR SO ACROSS THE BOARD AS SKY COVER AND WARM AIR ADVECTION ENSURE THAT COOLING WILL BE TEMPERED. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 306 PM CST THU JAN 9 2014 FOCUS IS ON POTENTIAL FOR LIGHT PRECIPITATION AS A SHORTWAVE TROUGH CROSSES THE CENTRAL PLAINS. WATER VAPOR IMAGERY INDICATED A PROGRESSIVE PATTERN IN THE WESTERLIES WITH A SHORTWAVE TROUGH DIGGING OVER THE ROCKIES EARLY THIS AFTERNOON. STRATUS AND SNOW COVER HAS IMPACTED TEMPERATURES TODAY...WITH THE STRATUS SLOW TO ERODE ACROSS OUR NORTHWEST ZONES...WHILE A NEW AREA OF STRATUS IS ADVECTING NORTHWARD THROUGH KS EARLY THIS AFTN. TEMPS HAVE MANAGED TO REACH THE MID 20S TO THE MID 30S SO FAR WITH A FEW MORE HOURS OF INSOLATION LEFT. FOR TONIGHT...SOUTHERLY LLVL FLOW INCREASES AHEAD OF THE TROUGH EMERGING ONTO THE HIGH PLAINS. STRATUS WILL CONTINUE TO ADVECT TO THE NORTH AND EAST AND SIMILAR TO THIS MORNING WE ARE LOOKING AT THE POTENTIAL FOR FOG DEVELOPMENT. WINDS LOOK TO REMAIN STEADY ENOUGH TO LIMIT DENSE FOG POTENTIAL BUT WILL NEED TO MONITOR AS THE RAP AND HRRR INDICATE SOME LOCATIONS COULD SEE DENSE FOG. AHEAD OF THE APPROACHING TROUGH...ISENTROPIC LIFT INCREASES AS INDICATED ON THE 295K SURFACE...PRIMARILY ORIENTED ACROSS OUR SOUTHEAST ZONES AND THE LIFT OVER THE LLVL MOISTURE COULD LEAD TO FREEZING DRIZZLE TOWARD MORNING AND THIS REMAINS IN THE FORECAST. ALSO ACROSS OUR WESTERN ZONES...HAVE INTRODUCED LOW POPS TOWARD DAYBREAK FRIDAY AS THE MID LEVEL TROUGH REACHES THIS AREA AND FORECAST SOUNDINGS FROM THE RAP INITIALLY INDICATE THE POTENTIAL FOR FREEZING DRIZZLE...THEN SATURATE TO MORE OF A IP/SN SOUNDING. HAVE MENTIONED ZL/IP FOR NOW WITH PCPN TYPE TRANSITIONING TO R/S DURING THE DAY FRIDAY. THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY ON HOW MUCH PCPN WILL BE AROUND DURING THE DAY ON FRIDAY WITH THE NAM REMAINING THE DRIEST AMONGST THE MODELS. THE SURFACE COLD FRONT SWEEPS EASTWARD FRIDAY MORNING...AND THE MID LEVEL TROUGH EXTENDS ACROSS OUR CENTRAL CWA AROUND MIDDAY BEFORE TRANSLATING EASTWARD DURING THE AFTERNOON. MID LEVEL MOISTURE INCREASES AS THE TROUGH MOVES IN AND A NARROW BAND OF MID LEVEL FRONTOGENESIS/LIFT MOVE ACROSS FM LATE MORNING INTO EARLY AFTERNOON...MORE ALIGNED ACROSS THE EASTERN HALF OF OUR CWA. HAVE INCREASED POPS DURING THIS TIME FRAME AS SPC WRF...GFS...ECMWF AND EVEN THE GEM INDICATE THE POTENTIAL FOR BANDED PCPN. FORECAST SOUNDINGS INDICATE THE POSSIBILITY OF A QUICK SHOT OF SNOW INITIALLY THEN DRY OUT/WARM BEHIND THE TROUGH AND HAVE MAINTAINED A SIMPLE RAIN/SNOW MIX FOR PCPN TYPE ATTM. WITH A WARMING TEMP PROFILE...GENERALLY DO NOT EXPECT MUCH IN THE WAY OF ACCUMULATION BUT WOULD NOT BE SURPRISED TO SEE MINOR AMOUNTS...GENERALLY UNDER ONE HALF OF AN INCH. THE TROUGH AXIS SHIFTS EASTWARD BY FRIDAY EVENING WITH CONDITIONS DRYING OUT/CLOUDS DECREASING IN SUBSIDENCE BEHIND THE DEPARTING SYSTEM. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 306 PM CST THU JAN 9 2014 OVERALL...THE LONG TERM PERIOD LOOKS TO BE MOSTLY DRY. BY FRIDAY NIGHT...THE MAIN TROUGH AXIS AND SURFACE LOW PRESSURE SYSTEM HAVE SHIFTED TO THE EAST OF THE PLAINS...WHILE AN UPPER LEVEL RIDGE AXIS SLOWLY BEGINS TO SHIFT ACROSS THE ROCKIES. WITH THIS RIDGE...AND A DEVELOPING LEE SURFACE TROUGH...SOUTHWEST WINDS WILL HELP BRING WARMER AIR TO THE PLAINS FOR SATURDAY. WENT A BIT ABOVE GUIDANCE FOR SATURDAY...WITH MOSTLY SUNNY SKIES AND SOUTHWEST WINDS...SEE NO REASON WHY WE CANNOT REACH THE UPPER 40S TO EVEN NEAR 50. BY SUNDAY...A WEAK UPPER LEVEL DISTURBANCE SHIFTS ACROSS THE PLAINS HELPING TO BREAK DOWN THE RIDGE. AS THE MAIN SURFACE LOW REMAINS WELL TO THE NORTH OF THE REGION...AN ASSOCIATED COLD FRONT WILL PASS THROUGH THE PLAINS SUNDAY. AT THIS POINT...WILL NOT REINTRODUCE POPS TO THE FORECAST AS THE SURFACE LOW REMAINS WELL TO THE NORTH. THAT BEING SAID...CANNOT RULE OUT A FEW SPRINKLES OR FLURRIES DURING THE DAY AND NIGHT ON SUNDAY. THE WAVE DEEPENS ACROSS THE PLAINS BY MONDAY...BRINGING COOLER 850 MB TEMPERATURES INTO THE OUTLOOK AREA. PERHAPS MONDAY MIGHT NEED TO BE A TAD COOLER THAN FORECAST BUT STILL CURRENTLY EXPECTING MID 40S FOR HIGHS. THROUGH THE REST OF THE LONG TERM...NUMEROUS WAVES CONTINUES TO DIVE SOUTH AND SKIRT ALONG THE PLAINS. HOWEVER...NONE OF THEM SUGGEST ANYTHING IN THE WAY OF PRECIPITATION OR A LONG LASTING COLD SPELL. IN FACT...RIDGING REBOUNDS ACROSS THE AREA BY WEDNESDAY BRINGING TEMPERATURES BACK UP TO NEAR 50. TOWARDS THURSDAY...YET ANOTHER UPPER LEVEL WAVE/CLOSED LOW WILL SHIFT THROUGH THE GREAT LAKES REGION DRAGGING A COLD FRONT ACROSS THE AREA. && .AVIATION...(FOR THE 00Z KGRI TAF THROUGH 00Z FRIDAY EVENING) ISSUED AT 555 PM CST THU JAN 9 2014 STRATUS WILL CONTINUE DO DESCEND OVERNIGHT WITH LOWERING VISIBILITY. MODELS ARE NOT INITIALIZING WELL...SO GOING WITH BEST GUESS. FOLLOWED MORE CLOSELY TO NAM MOS. FREEZING DRIZZLE SHOULD REMAIN SOUTH OF THE TERMINAL OVERNIGHT. COULD GET SOME RAIN/SNOW AS A TROUGH APPROACHES. WHEN THE WIND SWITCHES TO THE WEST/NORTHWEST BEHIND THE TROUGH...VISIBILITY AND CEILING WILL IMPROVE. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...HEINLEIN SHORT TERM...FAY LONG TERM...SALTZMAN AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS RALEIGH NC
307 AM EST FRI JAN 10 2014 .SYNOPSIS...MOISTURE INCREASES OVER THE REGION TODAY AS HIGH PRESSURE MOVES EAST INTO THE ATLANTIC. A STRONG COLD FRONT SWEEPS ACROSS THE REGION SATURDAY. HIGH PRESSURE BUILDS BACK IN ON SUNDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 305 AM FRIDAY... WATER VAPOR IMAGERY SHOWS AT LEAST MODEST MID-LEVEL SHORTWAVES MOVING TOWARD CENTRAL NORTH CAROLINA FROM THE SOUTHWEST...WHILE THE 00Z UPPER-AIR INFORMATION NOTED INCREASING 700MB AND 850MB MOISTURE UPSTREAM...AND 500MB DIFFLUENCE JUST TO OUR WEST. WITH THE APPROACH OF THE SHORTWAVES...MODEL FORECAST LIFT INCREASES AS WELL...WITH MODEST UPPER-LEVEL DIFFLUENCE TAKING PLACE FOR MUCH OF THE DAY. GUIDANCE POPS ARE HIGH...AND CURRENTLY THIS SEEMS REASONABLE GIVEN THE AVAILABLE SYNOPTIC LIFT AND INCREASING MOISTURE. THE VARIETY OF WRF GUIDANCE IS BULLISH ON PRECIPITATION CHANCES AS WELL...WITH THE LATEST HRRR WRF NOTING LIKELY CHANCES FOR PRECIPITATION AS FAR EAST AS THE NORTHEAST COASTAL PLAIN EARLY THIS AFTERNOON. WILL FORECAST BASICALLY CATEGORICAL CHANCES FOR RAIN TODAY MAINLY ALONG AND WEST OF U.S. 1...AND ESSENTIALLY LIKELY CHANCES EAST OF THERE. THE LATEST SPC MESOANALYSIS SHOWED THE WET-BULB ZERO LINE NORTH OF CENTRAL NORTH CAROLINA...BASICALLY NEAR OR NORTH OF THE VIRGINIA BORDER COINCIDENT WITH THE PIEDMONT...AND IN MANY AREAS THE SURFACE DEW POINT WAS APPROACHING...OR EVEN ABOVE...30 DEGREES. THE IMMEDIATE TRIAD HAD DEW POINTS STILL AROUND 20...BUT GIVEN THE KEXX DEW POINT ABOVE 32...AND TEMPERATURES IN THE TRIAD AROUND 40...THINK THE POTENTIAL FOR ANY FREEZING PRECIPITATION IS VERY SLIM AND THIS FORECAST WILL CONTINUE TO BE ALL LIQUID. TEMPERATURES TODAY WILL BE SOMEWHAT CHALLENGING...BUT WITH THE CLOUD COVER AND PRECIPITATION MOVING IN FROM THE SOUTHWEST...IT MAY BE DIFFICULT FOR MUCH OF A RISE. WILL KEEP IN MIND...THOUGH...THAT TEMPERATURES IN MANY LOCATIONS ARE AT LEAST AROUND 40...AND IN THE MID 40S IN PARTS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN. WILL STILL LIKELY HEDGE TOWARD THE COOLER SIDE OF GUIDANCE...OR A BLEND SUCH AS TOWARD THE TRIAD WHERE THE MET 39 MAY BE TOO COOL BUT THE MAV 46 MAY BE TOO WARM GIVEN THE EXPECTED NORTHEAST FLOW AND MORE AREAS OF RAIN THROUGHOUT THE DAY. STILL...A GOOD TEMPERATURE RANGE ANTICIPATED FROM AROUND 40 TO THE LOWER 40S NORTHWEST...TO THE LOWER 60S TOWARD KCTZ. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... AS OF 305 AM FRIDAY... TONIGHT...THE BETTER LIFT THAT IS FORECAST BY THE GFS TODAY MOVES OFF TO THE EAST...BEFORE BETTER LIFT TAKES PLACE AGAIN ALONG AND IN ADVANCE OF THE STRONG COLD FRONT TO MOVE THROUGH SATURDAY. GFS BUFR SOUNDINGS SHOW THE LOW-LEVELS REMAINING FAIRLY SATURATED ACROSS CENTRAL NORTH CAROLINA...AS 850MB WINDS START TO INCREASE OVERNIGHT. WHILE 850MB THETA-E VALUES INCREASE STEADILY TODAY INTO THIS EVENING...THE GFS DOES FORECAST A PERIOD OF DECREASING 850MB THETA-E LATE TONIGHT INTO EARLY SATURDAY MORNING. IT IS IN THIS SAME PERIOD WHERE THE STATISTICAL GUIDANCE SHOWS A SHORT DIMINISHING TREND IN CHANCES FOR RAIN...AND THE CONSENSUS OF WRF GUIDANCE NOTES LESSER COVERAGE OF PRECIPITATION. THE CURRENT THINKING IS THAT SCATTERED TO NUMEROUS AREAS OF RAIN AND DRIZZLE THROUGH THE EVENING AND INTO THE OVERNIGHT HOURS MAY BECOME MORE ISOLATED TO SCATTERED LATE TONIGHT...POSSIBLY INCREASING AGAIN TOWARD THE YADKIN RIVER VERY LATE TONIGHT INTO EARLY SATURDAY IN GOOD ISENTROPIC LIFT ON THE 295K AND 300K SURFACES. OVERNIGHT LOWS MAY OCCUR EARLY BEFORE TEMPERATURES SLOWLY INCREASE DURING THE NIGHT. ONCE AGAIN WILL LEAN TOWARD A BLEND OF THE GUIDANCE IN THE TRIAD WHERE THERE IS THE LARGEST DISCREPANCY BETWEEN THE MAV AND THE MET...AND RIGHT NOW MAINLY ON THE COOLER SIDE ELSEWHERE THOUGH...AS NOTED...READINGS SHOULD GRADUALLY RISE OVERNIGHT. SATURDAY INTO SATURDAY NIGHT...PRECIPITATION CHANCES INCREASE SOLIDLY WITH THE APPROACH AND PASSAGE OF THE FRONT. HEIGHT FALLS ALOFT SHOULD BE STRONG AS WELL AS THE MID-LEVEL TROUGH APPROACHES FROM THE WEST LATE IN THE DAY SATURDAY. INSTABILITY IS NOT GREAT BASED ON THE MODEL SOUNDING LAPSE RATES AND THE MIXED-LAYER CAPE FORECAST ON THE GFS IN THE LOWEST KM. IN FACT...THE MLCAPE REGISTERS ONLY TOWARD THE FAR SOUTHEAST...FROM ABOUT KMEB TO KGSB OR SO... WITH VALUES OF 500J/KG OR LESS. INTERESTINGLY...THOUGH...DOWNDRAFT CAPE INCREASES NOTICABLY ALONG AND NORTH OF U.S. 64 DURING THE AFTERNOON TO VALUES AROUND 700J/KG. EVEN THOUGH THE GFS BUFR SOUNDINGS SHOW THE MIXED LAYER TO BE FAIRLY SHALLOW SATURDAY AFTERNOON...WHERE THERE IS EVEN A BIT OF INSTABILITY...WINDS ALOFT INCREASE RAPIDLY TO 40 TO 50KT. THUNDER...OVERALL...MAY BE SOMEWHAT DIFFICULT TO COME BY...BUT GIVEN THE 40 TO 50KT 925MB WINDS IN THE AFTERNOON...AND 60 TO 70KT AT 850MB ALONG WITH GOOD THICKNESS PACKING AS THE FRONT MOVES THROUGH...A STRONGLY-FORCED LINE OF SHOWERS COULD TAKE PLACE RESULTING IN GUSTY WINDS. WILL NOTE THE POTENTIAL FOR STRONG TO SEVERE CONDITIONS IN THE HWO FOR SATURDAY... MAINLY IN THE AFTERNOON AND...FOR THE MOST PART...EAST OF THE FAR WESTERN PIEDMONT. MAV GUIDANCE FOR HIGHS SATURDAY ARE WARM...AND AT KRDU ARE ONLY A COUPLE OF DEGREES SHY OF THE RECORD. FOR NOTE... HIGH TEMPERATURE RECORDS ARE 73 AT KGSO IN 1949...AND 73 AT KRDU AND 79 AT KFAY IN 1930. ONCE AGAIN...WILL CURRENTLY PLAN A FORECAST WITH A BLEND OF THE MAV AND MET MOS. DRYING TAKES PLACE SATURDAY NIGHT AND THE CHANCES FOR PRECIPITATION DIMINISH WEST TO EAST AS K INDICES GO MOSTLY NEGATIVE BY 12Z SUNDAY. GUSTY WINDS IN THE EVENING DIMINISH SOME OVERNIGHT...AND THE APPROACH OF THE STRONG TROUGH ALOFT COULD LINGER CLOUDS AND SOME RAIN CHANCES THROUGH THE EVENING...AND INTO THE EARLY PART OF THE OVERNIGHT HOURS EAST OF U.S. 1. OVERNIGHT LOWS AROUND 40 TO THE MID 40S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 305 AM FRIDAY... THE LONG WAVE TROUGH AXIS WILL BE EXITING THE EAST COAST EARLY SUNDAY...WITH INCREASING HEIGHTS ACROSS OUR REGION THROUGH THE DAY. AT THE SURFACE...A HIGH PRESSURE CENTER WILL QUICKLY MOVE FROM THE NORTHERN GULF COAST AT 12Z SUNDAY TO A POSITION OFF THE SE COAST BY 00Z MONDAY. FOR OUR SENSIBLE WEATHER...SUBSIDENCE AND SUBSEQUENT DRYING WILL YIELD MOSTLY SUNNY SKIES DURING THE DAY. LOW LEVEL THICKNESSES...WHILE EXPECTED TO BOTTOM OUT AROUND 1305M EARLY IN THE DAY BEHIND THE DEPARTING TROUGH...WILL INCREASE TO AROUND 1330M BY LATE AFTERNOON. THUS LOOK FOR HIGHS TO RANGE FROM THE MID 50S NW TO LOWER 60S SE. SUNDAY NIGHT...THE MID/UPR RIDGE AXIS WILL BE TO OUR EAST AND THE NEXT TROUGH WILL BE MOVING ACROSS THE PLAINS. INCREASING SW FLOW ALOFT WILL RESULT IN THICKENING MID/HI CLOUDS ACROSS OUR AREA. LOWS IN THE MID-UPR 30S. MONDAY WILL SEE INCREASING CLOUDS AHEAD OF THE AFOREMENTIONED TROUGH...WHICH WILL BE CROSSING THE MISS RIVER VALLEY BY 00Z TUESDAY. HIGHS WILL CLIMB WELL ABOVE NORMAL IN THE PRE-FRONTAL AIRMASS. HIGHS IN THE LOWER 60S. THEN...SUBSTANTIAL DIFFERENCES CONTINUE IN THE LATEST GFS AND ECMWF RUNS REGARDING THE TIMING AND STRENGTH OF THE PROGRESSIVE BUT DAMPENING SHORT WAVE PROGGED TO LIFT NE AND ACROSS OUR AREA MONDAY NIGHT (PER GFS) OR LATE MONDAY NIGHT AND DURING THE DAY TUESDAY (PER ECMWF). THE ECMWF IS THE WETTER OF THE TWO THANKS TO ITS STRONGER SHORT WAVE AND MUCH-STRONGER (COMPARED TO GFS) LOW LEVEL JET AND MOISTURE TRANSPORT...THUS SHOWING AROUND 1/2 INCH QPF. IF THE TRENDS GO THE ECMWF WAY WITH FUTURE RUNS...WILL ALSO NEED TO KEEP A CLOSE EYE ON THERMAL PROFILES AND THE POTENTIAL FOR CONVECTION ON TUESDAY ALONG AND AHEAD OF THE COLD FRONT. BY LATE TUESDAY...THE COLD FRONT WILL BE TO OUR EAST...WITH SUBSIDENCE...CAA...AND DRYING IN IT`S WAKE. WE`LL THEN TURN OUR ATTENTION TO THE NEXT SHORT WAVE PROGGED TO DROP SE ACROSS THE MIDWEST AND OH VALLEY TUESDAY NIGHT. THE GFS AND ECMWF ARE IN DECENT AGREEMENT EARLY WITH THIS SYSTEM WHILE IT`S UPSTREAM OF US...BUT THEN START TO DIFFER QUITE DRAMATICALLY AS THE WAVE BOTTOMS OUT ACROSS THE CAROLINAS. THE ECMWF IS MUCH SLOWER AND CLOSES OFF THE MID LEVEL WAVE AS IT CROSSES THE CAROLINAS AND RESULTS IN SFC CYCLOGENESIS JUST OFF THE COAST. THE GFS ON THE OTHER HAND IS MUCH FASTER WITH AN OPEN WAVE THAT QUICKLY MOVES ACROSS AND EXITS OUR AREA. WHILE FORECAST SOUNDINGS AND PARTIAL THICKNESSES FROM BOTH SUGGEST THAT THE AIRMASS WILL LIKELY BE COLD ENOUGH FOR A MIX OF RAIN/SNOW OR ALL SNOW...BOTH SOLUTIONS ARE RATHER MOISTURE-STARVED WITH NO GULF AND VERY LITTLE ATLANTIC MOISTURE...UNTIL THE SYSTEM IS TO OUR EAST. SO FOR NOW...WILL KEEP POPS WITH THIS SYSTEM LIMITED TO CLIMO VALUES. THIS NW FLOW SYSTEM APPEARS TO BE THE LOWER-IMPACT TYPE THAT RESULTS IN PERHAPS A FEW FLURRIES...OR PERHAPS A BRIEF SNOW SHOWER OR TWO...WHICH WOULD OCCUR LATE WEDNESDAY OR WEDNESDAY NIGHT. THEN FOR THE LATTER HALF OF THE WEEK...THURSDAY LOOKS DRY WITH A SHORTWAVE RIDGE CROSSING THE AREA...THEN ANOTHER MOISTURE-STARVED SHORTWAVE TROUGH IS PROGGED TO MOVE ACROSS UNEVENTFULLY BY WEEKS END. MEX TEMPS LOOK TOO HIGH FOR THE LATTER HALF OF NEXT WEEK GIVEN LOW LEVEL THICKNESSES...THUS WILL MAKE APPROPRIATE DOWNWARD ADJUSTMENTS...TEMPS NEAR OR SLIGHTLY BELOW NORMAL DURING THIS TIME. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 105 AM FRIDAY... GRADUALLY DIMINISHING CONDITIONS WILL OCCUR IN CENTRAL NORTH CAROLINA DURING THE 06Z VALID TAF PERIOD. ALREADY...NUMEROUS AREAS OF RAIN WERE DEVELOPING OVER THE UPSTATE OF SOUTH CAROLINA MOVING INTO NORTH CAROLINA...WHERE CEILINGS WERE FALLING INTO THE MVFR RANGE. AS RAIN OCCURS...ANTICIPATE CEILINGS LOWERING TO MVFR...THEN AS MOISTURE CONTINUES TO INCREASE ALL MODELS SUPPORT CEILINGS FALLING TO IFR OR LIFR. RAIN SHOULD OCCUR LATEST TOWARD KRWI...AND ANTICIPATE AREAS OF LIGHT RAIN AND/OR DRIZZLE CONTINUING FROM LATE TODAY THROUGH THE EVENING. WINDS VEER ALOFT BUT THE LATEST GUIDANCE SUGGESTS WIND SPEEDS MORE GRADUALLY INCREASE THROUGH AND ABOVE 2000FT. AS A RESULT...HAVE KEPT LLWS OUT OF THE TAFS FOR THE 06Z ISSUANCE. BEYOND THE 06Z VALID TAF PERIOD...CONCERNS FOR LLWS INCREASE... THOUGH THE SURFACE WINDS MAY ALSO INCREASE ENOUGH LATE TONIGHT AND INTO SATURDAY TO KEEP LLWS ON THE MARGINS AS THE SURFACE WINDS VEER. WIDESPREAD SUB-VFR CONDITIONS...MANY AREAS IFR OR LIFR...CONTINUE INTO SATURDAY...AHEAD OF A STRONG COLD FRONT THAT SWEEPS ACROSS CENTRAL NORTH CAROLINA. WHILE AN ISOLATED THUNDERSTORM COULD OCCUR SATURDAY IN CENTRAL NORTH CAROLINA...A BAND OF SHOWERS PRODUCING GUSTY WESTERLY WINDS MOVING ACROSS CENTRAL NORTH CAROLINA DURING THE AFTERNOON AND VERY EARLY EVENING COULD CERTAINLY POSE AN AVIATION CONCERN. AVIATION INTERESTS OPERATING SATURDAY SHOULD MONITOR THE LATEST CONVECTIVE AVIATION INFORMATION AND THE TIMING OF ANY SUCH BAND. CONDITIONS RAPIDLY BECOME VFR SATURDAY NIGHT CONTINUING INTO MONDAY. A PERIOD OR TWO OF MVFR CONDITIONS IS POSSIBLE IN LIGHT PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF SHORT TERM...DJF LONG TERM...NP AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
106 AM EST FRI JAN 10 2014 .SYNOPSIS...MOISTURE INCREASES OVER THE REGION TODAY AS HIGH PRESSURE MOVES EAST INTO THE ATLANTIC. A STRONG COLD FRONT SWEEPS ACROSS THE REGION SATURDAY. HIGH PRESSURE BUILDS BACK IN ON SUNDAY. && .NEAR TERM /TONIGHT THROUGH FRIDAY NIGHT/... AS OF 930 PM THURSDAY... TONIGHT: A DETERIORATING SHORTWAVE MOVING THROUGH THE OHIO VALLEY HAS STRENGTHENED THE PRESSURE GRADIENT BETWEEN ITSELF AND THE SURFACE HIGH OVER THE MID-ATLANTIC. STRONG WARM AIR ADVECTION...EASILY DEPICTED BY A VERY LARGE WARM NOSE AT 925 MB HAS CONTINUED TO CHARGE NORTHWARD THIS EVENING AND WILL CONTINUE TO DO SO OVERNIGHT. THIS WILL HELP TO LIMIT THE THREAT OF ANY FREEZING RAIN IN THE TRIAD OVERNIGHT. CURRENT RUN OF THE RAP MODEL HAS TEMPERATURES ONLY DOWN TO ABOUT 39 DEGREES OR SO IN THE TRIAD AND 37 IN ROXBORO BEFORE THE ONSET OF PRECIPITATION AND THE 00Z RUN OF THE NAM HAS ABOUT 35 DEGREES AND BOTH MODELS HAVE WETBULB TEMPERATURES AT ABOUT THE SAME. AS FAR AS OBSERVATIONS ARE CONCERNED AS OF 2Z KINT WAS RUNNING AT 42 DEGREES WITH A DEWPOINT OF 14 BUT DEWPOINTS JUST A COUNTY SOUTHWARD IN THE MID 20S WHICH WILL BE ADVECTING NORTHWARDS OVER THE NEXT COUPLE OF HOURS. AT THIS POINT HAVE DECIDED AGAINST AN ADVISORY FOR FREEZING WITH FAIRLY HIGH CONFIDENCE THAT NONE WILL OCCUR AND EVEN IF SO...IMPACTS WOULD BE VERY MINIMAL TO NONE AT ALL. WILL ADJUST MINIMUM TEMPERATURES UPWARDS WITH NEXT UPDATE...MID TO UPPER 30S ACROSS THE AREA. ALTHOUGH FREEZING PRECIPITATION IS NOT EXPECTED...STRONG ISENTROPIC LIFT AND THE ADVECTION OF WARM MOIST LOW LEVEL AIR WILL BRING PRECIPITATION MAINLY TO THE WESTERN PIEDMONT WITH THE RAP SHOWING FIRST ACCUMULATIONS IN THE SW AFTER 6Z AND SPREADING UP INTO THE TRIAD BY 8 OR 9Z. CURRENT RADAR SHOWS OUR FIRST RETURNS OF THE NIGHT BUT THIS IS IN ALL LIKELIHOOD NOT YET REACHING THE GROUND. IN GENERAL THE EAST WILL BE DRY COMPARED TO THE WEST BUT CANNOT RULE OUT LIGHT RAIN EVEN IN EASTERN LOCALS BY DAYBREAK. -ELLIS FRIDAY AND FRIDAY NIGHT: THE BEST SURGE OF ISENTROPIC LIFT LOOKS TO MAXIMIZE ACROSS THE AREA BY LATE MORNING BEFORE LIFTING OFF TO THE NORTH...WITH CONTINUED BROAD WAA THROUGH THE REMAINDER OF THE DAY. SO WE COULD BE LOOKING AT A LULL IN MEASURABLE PRECIP BY NOON WITH MORE IN THE WAY OF DRIZZLE THROUGH THE AFTERNOON AND EVENING...ESPECIALLY IN THE EAST REMOVED FROM THE HEART OF THE DAMMING AIRMASS AND BETTER FGEN GRADIENT ACROSS THE WESTERN PIEDMONT. TEMPERATURES: WILL SEE THE TYPICAL SHARP NW-SE TEMPERATURE GRADIENT ASSOCIATED WITH CAD EVENTS...RANGING FROM MID TO UPPER 30S IN THE TRIAD TO MID AND UPPER 50S IN THE FAR SE COASTAL PLAIN. MODELS INDICATE WEDGE WILL ERODE OVERNIGHT FRIDAY NIGHT WITH LOW TEMPS SAT MORNING LIKELY OCCURRING AT MIDNIGHT WITH RISING TEMPS THEREAFTER. WILL INDICATE TEMPS RISING INTO THE MID/UPPER 50S TO LOWER 60S ALONG/EAST OF HWY 1 (WARMEST SE COASTAL PLAIN) TO MID/UPPER 40S IN THE TRIAD. -CBL && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 225 PM THURSDAY... FOR SAT/SAT NIGHT: A WET AND POTENTIALLY STORMY DAY. THE WARM FRONTAL ZONE WILL LIKELY STILL BE SITUATED SE OF THE TRIAD AT DAYBREAK BUT WE SHOULD BE FULLY IN THE WARM SECTOR BY AROUND 18Z SAT AS THE WARM FRONTAL MOMENTUM SHOULD EASILY OVERTAKE THE THINNING STABLE POOL. (THE GFS IS A FEW HOURS SLOWER THAN THE NAM WITH ITS WARM FRONTAL PASSAGE.) DEEP MID LEVEL TROUGHING THROUGH THE CENTRAL CONUS WILL SHIFT EASTWARD THROUGH THE EASTERN CONUS SAT/SAT NIGHT... WITH SURFACE COLD FRONT PASSAGE THROUGH NC SAT AFTERNOON AND EVENING. CERTAINTY IS HIGH THAT WE`LL SEE WIDESPREAD SHOWERS AHEAD OF THIS FRONT GIVEN THE SURGE IN MOISTURE WITH A STRONG GULF FEED AND INCOMING PW VALUES OF 1.3-1.7. VIGOROUS DYNAMIC FORCING WILL CONTRIBUTE TO ASCENT WITH STRENGTHENING UPPER LEVEL DIVERGENCE AND MID LEVEL DPVA... 500 MB WINDS OVER 500 MB... 12-HR HEIGHT FALLS OF 180-240 METERS... AND AN 850 MB JET FROM THE SW INTENSIFYING TO 50- 60 KTS. THESE POTENT DYNAMICS APPEAR TO MAXIMIZE OVER NC AROUND 18Z (GIVE OR TAKE AN HOUR OR TWO)... WHEN WE ALSO SEE RISING MODEL FORECAST INSTABILITY... WITH THE NAM DEPICTING 400-800 J/KG OF SURFACE CAPE ALONG/EAST OF HIGHWAY 1. LOW LEVEL SHEAR RAMPS UP EARLY SAT AS WELL... WITH 0-1 KM SHEAR TOPPING OUT AT 45-50 KTS (HIGHEST IN THE PIEDMONT) SAT AFTERNOON... AND LOW LCLS. ALL OF THIS EQUATES TO A RISK OF STRONG FAST-MOVING BOWING SEGMENTS AND PERHAPS A SUPERCELL OR TWO... PROVIDED THE PREDICTED INSTABILITY CAN BE REALIZED AND WE DO INDEED SEE SURFACE DEW POINTS IN THE 60S AS MODELS GENERALLY AGREE WILL HAPPEN. THE ONE CAVEAT IS THE POSSIBILITY OF MORNING SHOWERS PRECEDING THE PRIMARY BAND OF SHOWERS... AS THIS MAY TEMPER INSTABILITY ESPECIALLY IN THE WRN HALF OF THE CWA WHERE THE LOW LEVEL SHEAR WILL BE STRONGEST. WILL ADD A MENTION OF THUNDER SAT... ESPECIALLY EAST... AND ADD A MENTION OF POSSIBLE STRONG STORMS TO THE HAZARDOUS WEATHER OUTLOOK. EXPECT MOSTLY CLOUDY TO CLOUDY SKIES THROUGH THE DAY... QUITE WINDY WITH SUSTAINED WINDS OF 15-20 MPH GUSTING TO 35 MPH (AND OCCASIONALLY HIGHER)... AND CATEGORICAL POPS. BASED ON MODEL GUIDANCE AND SREF PROBABILITIES... RAINFALL AMOUNTS ARE EXPECTED TO REACH AROUND 1.0- 1.25 INCHES FOR THE ENTIRE EVENT. EXPECT A SLOWER TEMP RISE IN THE TRIAD UNTIL THE VERY SHALLOW SURFACE-BASED STABLE POOL IS ERODED THERE... BUT OVERALL IT SHOULD BE A MILD DAY WITH HIGHS FROM THE LOW 60S NW TO LOW 70S SE. BOTH THE NAM AND GFS INDICATE CLEARING SKIES SAT NIGHT ALTHOUGH THE GFS IS MUCH FASTER WITH DEEP DRYING TAKING PLACE WHILE THE NAM IS SLOWER AND HOLDS ONTO PLENTY OF MOISTURE BELOW 600 MB WELL INTO THE EVENING. THE NAM ALSO STAYS WELL-MIXED FOR SEVERAL HOURS JUST BEHIND THE COLD FRONT AS THE 925-700 MB LAYER COOLS WITH THE DELAY IN SURFACE COOLING... AND THIS WOULD SUGGEST A FEW SHALLOW SHOWERS BEHIND THE FRONT. BUT IN EITHER CASE WE SHOULD SEE CLEARING AFTER MIDNIGHT WITH DEEP DRYING. WITH THE MIXING HOLDING THROUGH THE NIGHT... EXPECT WINDS TO STAY UP... AND THIS STIRRING WILL SOMEWHAT OFFSET THE COLD AIR ADVECTION AND HINDER THE DROP IN TEMPS. LOWS 40-49. FOR SUN/SUN NIGHT: MODELS INDICATE IMPRESSIVE HEIGHT RISES OF 220- 260 M BEHIND THE TROUGH AND STRONG MID LEVEL SUBSIDENCE AND WARMING STARTING IN THE PREDAWN HOURS SUNDAY. EXPECT CLEAR SKIES WITH MODIFIED SURFACE HIGH PRESSURE BUILDING IN FROM THE SW. THICKNESSES WILL HAVE COOLED MARKEDLY FROM SATURDAY BUT ARE STILL LIKELY TO BE ABOUT 5-10 M ABOVE NORMAL... EQUATING TO HIGHS OF 53-62... A TAD UNDER STATISTICAL GUIDANCE. THE SURFACE HIGH SHIFTS QUICKLY OFF THE SE COAST SUN NIGHT WITHIN A PROGRESSIVE LONGWAVE PATTERN ACROSS THE CONUS. AS OUR NEXT LONGWAVE TROUGH SHIFTS THROUGH THE CENTRAL STATES SUN NIGHT WITH A SHOT OF SOUTHERN STREAM ENERGY MOVING IN FROM THE SW... WE`LL SEE INCREASING SOUTHWEST FLOW ALOFT OVER NC RESULTING IN INCREASING AND THICKENING HIGH CLOUDS OVERNIGHT. LOWS 34-40. -GIH && .LONG TERM /MONDAY THROUGH THURSDAY... AS OF 245 PM THURSDAY... CHALLENGING FORECAST FOR THE EARLY TO MIDDLE PART OF NEXT WEEK AS SOME MODEL DISAGREEMENT EMERGES. THE LONGWAVE TROUGH OVER THE CENTRAL US EARLY MONDAY MORNING PROGRESSES EASTWARD THROUGH MON NIGHT WITH ENERGY DIGGING INTO THE TROUGH BASE... MUCH MORE DEEPLY OVER THE DEEP SOUTH ON THE ECMWF THAN THE GFS. AS A RESULT... THE ECMWF PULLS THE OLD FRONTAL ZONE TO OUR SOUTH WELL TO THE NNW AND BACK INTO NC AS A WARM FRONT BY LATE MON NIGHT... WITH A STRONG SURFACE CYCLONE MOVING NE THROUGH NC TUE MORNING. MEANWHILE... THE WEAKER AND FASTER GFS BRINGS THE FRONTAL ZONE BACK NW ONLY TO THE COASTAL CAROLINAS WITH A COLD FRONT (AND NO STRONG CYCLONE) SHIFTING THROUGH NC MON NIGHT. TOUGH TO PICK OUT A WINNER BETWEEN THESE TWO CAMPS... PARTICULARLY CONSIDERING THAT BOTH HAVE VARYING DEGREES OF POLAR STREAM ENERGY DIVING IN THE BACK SIDE OF THE LONGWAVE TROUGH EARLY TUE... WHICH SERVES TO DEEPEN THE TROUGH OVER THE EASTERN CONUS WED/THU. GIVEN THE UNCERTAINTY... WILL AVOID FORECASTING ANY EXTREMES... AND STICK WITH A CHANCE OF RAIN STARTING WITH THE APPROACH OF THE FRONT MON NIGHT... LASTING INTO TUE EVENING. BOTH THE GFS AND ECMWF SWING THE TROUGH BASE THROUGH NC WED WITH AT LEAST SOME CLOUDINESS AND POTENTIALLY SOME PRECIP AS WELL. THESE DETERMINISTIC MODELS SUGGEST THAT IT COULD BE A QUICK SHOT OF LIGHT MIXED RAIN/SNOW BASED ON FORECAST PARTIAL THICKNESSES... HOWEVER GIVEN THAT WE COULD HAVE SUBSTANTIAL DOWNSLOPE FLOW COMPONENT ESPECIALLY WITH A WEAKER SYSTEM... WILL PUT IN CLOUDS FOR NOW BUT HOLD OFF ON ANY PRECIP CHANCES ON WED. CLEARING BY THU WITH SOUTHERN STREAM HIGH PRESSURE BUILDING INTO THE SOUTHEAST. WILL KEEP TEMPS WITHIN A CATEGORY OF CLIMATOLOGY THROUGHOUT THIS PERIOD... BUT CONFIDENCE IS NOT HIGH... AS A MUCH STRONGER OR WEAKER SYSTEM COULD HAVE LARGE EFFECTS ON TEMPS. -GIH && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 105 AM FRIDAY... GRADUALLY DIMINISHING CONDITIONS WILL OCCUR IN CENTRAL NORTH CAROLINA DURING THE 06Z VALID TAF PERIOD. ALREADY...NUMEROUS AREAS OF RAIN WERE DEVELOPING OVER THE UPSTATE OF SOUTH CAROLINA MOVING INTO NORTH CAROLINA...WHERE CEILINGS WERE FALLING INTO THE MVFR RANGE. AS RAIN OCCURS...ANTICIPATE CEILINGS LOWERING TO MVFR...THEN AS MOISTURE CONTINUES TO INCREASE ALL MODELS SUPPORT CEILINGS FALLING TO IFR OR LIFR. RAIN SHOULD OCCUR LATEST TOWARD KRWI...AND ANTICIPATE AREAS OF LIGHT RAIN AND/OR DRIZZLE CONTINUING FROM LATE TODAY THROUGH THE EVENING. WINDS VEER ALOFT BUT THE LATEST GUIDANCE SUGGESTS WIND SPEEDS MORE GRADUALLY INCREASE THROUGH AND ABOVE 2000FT. AS A RESULT...HAVE KEPT LLWS OUT OF THE TAFS FOR THE 06Z ISSUANCE. BEYOND THE 06Z VALID TAF PERIOD...CONCERNS FOR LLWS INCREASE... THOUGH THE SURFACE WINDS MAY ALSO INCREASE ENOUGH LATE TONIGHT AND INTO SATURDAY TO KEEP LLWS ON THE MARGINS AS THE SURFACE WINDS VEER. WIDESPREAD SUB-VFR CONDITIONS...MANY AREAS IFR OR LIFR...CONTINUE INTO SATURDAY...AHEAD OF A STRONG COLD FRONT THAT SWEEPS ACROSS CENTRAL NORTH CAROLINA. WHILE AN ISOLATED THUNDERSTORM COULD OCCUR SATURDAY IN CENTRAL NORTH CAROLINA...A BAND OF SHOWERS PRODUCING GUSTY WESTERLY WINDS MOVING ACROSS CENTRAL NORTH CAROLINA DURING THE AFTERNOON AND VERY EARLY EVENING COULD CERTAINLY POSE AN AVIATION CONCERN. AVIATION INTERESTS OPERATING SATURDAY SHOULD MONITOR THE LATEST CONVECTIVE AVIATION INFORMATION AND THE TIMING OF ANY SUCH BAND. CONDITIONS RAPIDLY BECOME VFR SATURDAY NIGHT CONTINUING INTO MONDAY. A PERIOD OR TWO OF MVFR CONDITIONS IS POSSIBLE IN LIGHT PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...ELLIS/CBL SHORT TERM...HARTFIELD LONG TERM...HARTFIELD AVIATION...DJF
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
347 AM EST FRI JAN 10 2014 .SYNOPSIS... UPPER TROUGH EXITS EAST BY NOON. TEMPERATURES MODERATING INTO SATURDAY BEFORE COLD FRONT WITH RAIN CROSSES. WEAK HIGH PRESSURE PASSES SUNDAY. COLD FRONTS DUE EARLY AND LATE NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... RADAR IMAGES SHOW A BROAD AREA OF LIGHT PCPN BOUNCING FROM LIGHT RAIN TO MIXED SNOW MAINLY NORTHERN PORTIONS OF SOUTHEAST OH AND NORTHERN EXTREME OF WV. EXPECT THIS AREA TO GRADUALLY MOVE EASTWARD THROUGH THE EARLY MORNING HOURS. PCPN SHOULD BE PUSHED EAST OVER THE EASTERN MOUNTAINS BY MID MORNING LEAVING THE LOWLANDS PCPN FREE...AND DIMINISHING OVER THE MOUNTAINS TOWARDS NOON. THE HIGH RESOLUTION MODEL HRRR HAS THE CLOSER SOLUTION WHEN COMPARED WITH RADAR IMAGES. THE RUC13 LOOKS ABOUT 6 TO 12 HOURS SLOWER THAN ACTUAL WEATHER MOVING THROUGH. ADJUSTED POPS PER LATEST RADAR IMAGES AND THE MATCHING HRRR MODELS THROUGH FRIDAY MORNING. TEMPERATURES ACROSS THE LOWLANDS SLOWLY INCREASING MAKING TRANSITIONING PCPN INTO ALL RAIN. WARM AIR ADVECTION WILL CONTINUE UNDER SOUTHWEST FLOW KEEPING PCPN LIQUID AND BRINGING RELATIVELY WARMER TEMPERATURES COMPARED WITH PREVIOUS DAYS. BELIEVE ONCE RAIN SHOWERS MOVE EAST BY NOON...IT WILL BE A RELATIVELY DRY FRIDAY. HOWEVER...A STRONG COLD FRONT APPROACHES FROM THE WEST LATE TONIGHT...WITH A GOOD CHANCE FOR PCPN AND SOME GUSTY WIND. NOT EXITED ABOUT MODELS SHOWING H85 FLOW ABOUT 50 KNOTS LATER TONIGHT INTO EARLY SATURDAY MORNING. SOUTHWEST FLOW PARALLEL TO THE MOUNTAIN...UPGLIDE NOTICEABLE IN 280K ISENTROPIC CHARTS...AND THE POSSIBILITY OF NIGHT TIME DECOUPLING WILL MAKE THIS STRONG FLOW TO STRUGGLE TO MIX DOWN TO THE SFC TONIGHT. INCREASED ONSET OF PCPN TO CATEGORICAL LATE TONIGHT SPREADING FROM WEST TO EAST. WENT WITH THE MOST REASONABLE MOS CONSENSUS FOR TEMPERATURES THROUGH THE PERIOD. TEMPERATURES OVER THE EASTERN SLOPES COULD REMAIN AT OR BELOW FREEZING ON PROTECTED VALLEYS. THEREFORE...KEPT THE WINTER WEATHER ADVISORY FOR FREEZING RAIN FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 8 AM THIS MORNING. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... PACIFIC COLD FRONT STILL ON TRACK TO SWEEP ACROSS THE FORECAST AREA FROM WEST TO EAST SATURDAY MORNING...WITH ASSOC UPPER TROUGH PROGRESSING NORTHEASTWARD ACROSS THE GREAT LAKES REGION DURING THE DAY ON SATURDAY. STRONG LOW LEVEL WINDS PUSH INTO MAINLY THE WESTERN PARTS OF THE AREA OVERNIGHT FRI NIGHT...WHICH CONTINUE INTO THE SHORT TERM PERIOD EARLY SATURDAY MORNING. 850MB WINDS ARE PROGGED AROUND 70-75KTS ACROSS THE WESTERN ZONES AND NEAR 50KTS AT 925MB. WIND SPEEDS THIS STRONG AT THIS ALTITUDE WITH ASSOC PRECIP ALWAYS BRING SOME CONCERN...AS IT/S TOUGH TO KNOW JUST HOW MUCH PRECIP DRAG WILL BE ABLE TO BRING STRONG WINDS TO THE SURFACE. HOWEVER...WITH A STOUT INVERSION BELOW 900MB AND A TURNING OF WIND DIRECTION IN LOW-LEVELS SHOULD RESULT IN LESS RISK FOR HIGH WINDS AT THE SURFACE VERSUS PREVIOUS EVENTS THIS FALL/WINTER. SPC HAS NOT INCLUDED OUR FORECAST AREA IN A GENERAL RISK. NONETHELESS..SOMETHING TO WATCH EARLY SATURDAY MORNING AS THE PRECIP MOVES ACROSS. ALL IN ALL THOUGH...NOT MUCH CHANGE WITH PREV FORECAST THINKING. CATEGORICAL POPS EVERYWHERE DURING THE MORNING HOURS SATURDAY WITH THE FRONT. HIGH PWATS AROUND AN INCH SHOULD SPELL A FAIRLY QUICK QUARTER TO HALF INCH OF RAIN FOR MOST LOCATIONS...PERHAPS A LITTLE MORE IN THE EASTERN MOUNTAINS. NO HYDRO CONCERNS ARE EXPECTED WITH THIS SYSTEM HOWEVER. CONTINUED PREV FORECAST THINKING WITH REGARD TO A SLIGHT NON-DIURNAL TREND IN TEMPS ON SATURDAY WITH THE WARMEST 850MB/925MB TEMPS OCCURRING OVER WESTERN/CENTRAL AREAS BTWN 15Z-18Z SAT. THE BULK OF THE PRECIP SHOULD BE ALONG AND EAST OF THE I79 CORRIDOR BY 18Z SAT...WITH SYNOPTIC PRECIP WINDING DOWN AREA-WIDE BY 00Z SUN. WILL KEEP INHERITED HIGH CHANCE POPS HOWEVER ALONG THE EASTERN SLOPES A LITTLE LONGER WITH A WESTERLY UPSLOPE FLOW CONTINUING. STILL APPEARS THE STRONGEST WINDS COME LATE SAT AFTERNOON INTO THE EARLY OVERNIGHT HOURS SAT NIGHT POST-FRONT...WITH GUSTS IN THE HIGH COUNTRY TOPPING 40KTS. BY SATURDAY NIGHT ALL LOCATIONS EXCEPT THE EASTERN MOUNTAINS SHOULD BE PRECIP-FREE. HIGHER ELEVATIONS MAY SEE SOME LINGERING LIGHT RAIN OR SNOW SHOWERS THROUGH AROUND THE 06Z-09Z SUN TIME FRAME WITH DEPTH OF LLVL MOISTURE DECREASING...BUT AGAIN...AMOUNTS ARE EXPECTED TO BE VERY LIGHT WITH MOST AREAS PROBABLY ACTUALLY ONLY EXPERIENCING DRIZZLE OR FLURRIES. OVERNIGHT MINS BY EARLY SUN STILL EXPECTED TO BE IN THE LOW/MID 30S MOST LOWLAND LOCATIONS...WITH MID/UPPER 20S FOR THE MOUNTAINS. INITIALLY CLOUDY SKIES DURING THE EARLY OVERNIGHT HOURS SHOULD GRADUALLY BECOME MOSTLY CLEAR TO PARTLY CLOUDY FOR THE LOWLANDS BY DAWN SUNDAY...WITH OF COURSE LINGERING CLOUDS IN THE MOUNTAINS. SUNDAY AND SUNDAY NIGHT...SFC HIGH PRESSURE PASSES TO OUR SOUTH WITH WINDS BACKING FROM THE WEST TO THE SOUTH BY SUNDAY NIGHT. FLOW ALOFT ALSO BACKS FROM NEAR ZONAL TO SOUTHWESTERLY AS THE NEXT UPPER TROUGH DIGS QUICKLY SOUTHEAST INTO THE CENTRAL CONUS. STILL...A NICE PERIOD WITH MOSTLY SUNNY SKIES FOR ALL LOCATIONS IS EXPECTED. CONTINUED TO NUDGE MAX TEMPS UPWARD FOR SUNDAY...AS WAS THE PREVIOUS FORECAST TREND. 850MB/925MB TEMPS SUGGEST LOWLAND LOCATIONS NEAR THE CRW-HTS CORRIDOR APPROACHING 50F DEGREES. WILL RAISE TEMPS GENERALLY TO THE MID/UPPER 40S LOWLANDS...WITH MID 30S ON HIGHEST PEAKS. OVERNIGHT MINS SUNDAY NIGHT/MONDAY MORNING FOR THE LOWLANDS IN THE LOW/MID 30S STILL LOOK ON TRACK. DID RAISE EASTERN MOUNTAIN MINS UP AND ALSO CODED UP A NON-DIURNAL TEMP CURVE HERE...WITH DECENT 850MB WARM ADVECTION NOTED ON CONSENSUS OF MODEL OUTPUT IT APPEARS THAT THE MIN TEMP WILL BE REALIZED CLOSE TO MIDNIGHT FOR LOCATIONS SUCH AS SNOW WITH TEMPS CONTINUING A SLOW RISE TOWARDS DAWN MONDAY. && .LONG TERM /MONDAY THROUGH THURSDAY/... HIGH PRESSURE OF THE SE US WILL BRING A DRY START TO THE LONG TERM PERIOD. THERE IS POOR AGREEMENT BETWEEN THE ECMWF AND GFS ON SYSTEM ARRIVING LATE MONDAY. BOTH INDICATE A FRONTAL PASSAGE...BUT THE ECMWF ALSO SHOWS A SURFACE WAVE RIDING THE FRONT OUT OF THE SE...NORTHEAST JUST EAST OF THE APPALACHIANS. THE GFS DOES NOT HAVE THIS...AND IS INSTEAD JUST A COLD FRONTAL PASSAGE CONNECTED TO A SURFACE LOW NORTH OF THE GREAT LAKES. TRENDED TOWARD THE ECMWF...WHICH MESHES WELL WITH LATEST WPC GUIDANCE TOO. HAVE CHANCE POPS ACROSS WV ZONES WITH THE FRONT/SURFACE WAVE...SLIDE THOSE OUT TUESDAY. 500MB SHORTWAVE TROUGH PASSES WITH THE FRONT...WITH LARGER SCALE TROUGH ARRIVING MIDWEEK...BRINGING AN INCREASE IN POPS AGAIN TUESDAY NIGHT INTO WEDNESDAY. && .AVIATION /09Z FRIDAY THROUGH TUESDAY/... RADAR IMAGES INDICATE AN AREA OF SHOWERS MOVING FROM THE SOUTHWEST INTO WV AND SOUTHEAST OH OVERNIGHT. EXPECT MVFR CONDITIONS UNDER RAIN...MAINLY ALONG AND NORTH OF LINES FROM HTS TO CRW...AND CRW TO BKW AND ELEVATED TERRAIN. SOUTHWEST FLOW BRINGS WAA TO THE AREA...WHILE COLD AIR MASS REMAINS IN PLACE FAR NORTH OVER PORTIONS OF SOUTHEAST OH AND EXTREME NORTHERN WV. EXPECT SNOW MIXED WITH SLEET OR RAIN...OVERNIGHT TRANSITIONING TO ALL RAIN BY FRIDAY MORNING. SOUTH OF THE AFOREMENTIONED LINES PCPN SHOULD STAY ALL RAIN. BRIEF PERIODS OF IFR/MVFR CEILINGS EXPECTED AT BKW AFTER 09Z...AND ACROSS ALL SITES FRIDAY AFTERNOON AROUND 17Z. OTHERWISE...VFR/MVFR MIST AND RAIN EXPECTED FOR THE MOST PART ON FRIDAY. PCPN SHOULD START DIMINISHING FROM WEST TO EAST FROM 13Z TO 17 FRIDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY... ALTERNATE SCENARIOS: TIMING AND ONSET OF PRECIP MAY VARY. PRECIP TYPE AND CIG CATEGORY MAY VARY FROM FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE FRI 01/10/14 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H M H H H H H M H BKW CONSISTENCY H H H H H H M M M M M M EKN CONSISTENCY M H H H H H H H H H H H PKB CONSISTENCY M M H H H H H H H H H H CKB CONSISTENCY M M H H H H H H H H H H AFTER 06Z SATURDAY... IFR CONDITIONS IN RAIN COULD DEVELOP SATURDAY INTO SUNDAY IN STRONG FLOW ALOFT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZING RAIN ADVISORY UNTIL 8 AM EST THIS MORNING FOR WVZ046- 047. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/50 NEAR TERM...ARJ SHORT TERM...50 LONG TERM...MZ AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
102 AM EST FRI JAN 10 2014 .SYNOPSIS... UPPER TROUGH PASSES TONIGHT. TEMPERATURES MODERATING INTO SATURDAY BEFORE COLD FRONT WITH RAIN CROSSES. WEAK HIGH PRESSURE PASSES SUNDAY. COLD FRONTS DUE EARLY AND LATE NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... ADJUSTED POPS PER LATEST RADAR IMAGES AND THE MATCHING HRRR MODELS THROUGH FRIDAY MORNING. REST OF FORECAST REMAINS REPRESENTATIVE. KEPT WINTER WEATHER ADVISORY FOR FREEZING RAIN ACROSS POCAHONTAS AND RANDOLPH UNTIL 8AM FRIDAY. PREVIOUS DISCUSSION BELOW... 9 PM...TWEAKED POP FORECAST. PRECIPITATION HAVING A HARD TIME REACHING GROUND AT THIS POINT AS ATMOSPHERE STILL A BIT TOO DRY...BUT DEW POINTS ARE RISING...AND ATMOSPHERE MOISTENING UP...SO EXPECTING PRECIPITATION TO BE REACHING THE GROUND IN THE CWA SHORTLY. PREVIOUS DISCUSSION FOLLOWS... HIGH PRESSURE CURRENTLY DEPARTING OFF THE NEW YORK/NEW JERSEY COAST THIS AFTERNOON WITH MID LEVEL MOISTURE OVERSPREADING THE REGION. A TROUGH EMBEDDED IN THE 500MB FLOW WILL TRAVERSE THE MIDDLE OHIO VALLEY TONIGHT BRINGING THE NEXT ROUND OF PRECIPITATION FOR THE CWA. TWO MAIN ISSUES WILL BE AT PLAY HERE. FIRST IS THE TEMPERATURES LATE THIS EVENING AND EARLY TONIGHT AS THEY FALL INTO THE LOWER TO MIDDLE 30S OVER THE LOWLANDS. THE NORTHERN TIER OF COUNTIES COULD FLIRT WITH THE FREEZING MARK...AND WITH A WARM LAYER OFF THE SURFACE...MIXED PRECIPITATION TYPES ARE POSSIBLE AT THE ONSET. SOUNDINGS ARE MORE SUPPORTIVE OF THE SNOW/SLEET/RAIN REGIME THROUGH TIME THAN FREEZING RAIN WEST OF THE MOUNTAINS. THIS WARM LAYER ALOFT WEST OF THE MOUNTAINS WILL BE SUPPLIED BY INCREASING SOUTHWESTERLY FLOW THROUGH 850MB. THE SECOND ITEM IS THE SOUTH SOUTHEAST FLOW AT THE SURFACE...AND IN THE LOWER LEVELS ALONG THE EASTERN SLOPES OF THE NORTHEAST MOUNTAINS. THIS UPSLOPE WILL WORK AT TIMES IN CONJUNCTION WITH THE FORCING ALOFT FROM THE VORTICITY ADVECTION AND WILL RESULT IN FREEZING RAIN THANKS TO TEMPERATURES THAT WILL BEGIN COLDER THAN AREAS WEST AND SUPPORTED THROUGH 12Z FRIDAY BY THE COOL UPSLOPE FLOW. AFTER THIS TIME FRAME...WARM ADVECTION JUST ABOVE THE SURFACE WILL FINALLY TAKE OVER AND SCOUR OUT THE COLD AIR WEDGE ON THE EAST SIDE OF THE MOUNTAINS. IT IS IMPORTANT TO NOTE THAT THE NATURE OF THE FLOW BEING SOUTH SOUTHEASTERLY AS OPPOSED TO SOUTHEASTERLY WILL LIKELY EXCLUDE THE SOUTHERN MOUNTAINS FROM THE UPSLOPING CONDITIONS. EXPECTING THE BULK OF THE FREEZING RAIN TO FALL IN RANDOLPH AND POCAHONTAS COUNTIES...AND ALONG THE FAR EASTERN PORTIONS OF WEBSTER...NICHOLAS...AND FAYETTE. BY THE LATE MORNING FRIDAY...ALL ZONES SHOULD BE IN PLAIN RAIN AS THE DISTURBANCE ALOFT QUICKLY LIFTS INTO NEW ENGLAND AND THE SOUTH SOUTHEAST UPSLOPE CEASES. 850MB TEMPERATURES CONTINUE TO CLIMB THROUGH FRIDAY...AND WILL EXPECT SOME LOWLAND LOW 50S DESPITE THE LACK OF APPRECIABLE INSOLATION. && .SHORT TERM /TONIGHT THROUGH SUNDAY/... MODEL TIMING IS A LITTLE FASTER ON OCCLUSION THAT MOVES THROUGH SAT. PRECIPITATION ARRIVES AFTER MIDNIGHT FRI NT FROM THE W...AND IN THE GREENBRIER VALLEY ON SSE UPSLOPE FLOW THERE. PW VALUES CLIMB JUST OVER AN INCH SO A QUICK HALF INCH RAINFALL APPEARS PLAUSIBLE...HIGHER AMOUNTS IN THE MOUNTAINS AND LOWER IN THE W. STRONG LOW LEVEL WINDS AHEAD OF THE FRONT WILL NOT MIX DOWN VERY WELL GIVEN BOUNDARY LAYER INVERSION. PEAK GUSTS WILL BE BEHIND THE FRONT SAT AFTERNOON AND NT...UP OVER 40 KTS OVER THE HIGHER TERRAIN. THE FRONT MOVES THROUGH AROUND MIDDAY AND EARLY AFTERNOON...FOLLOWED BY LIGHT UPSLOPE SHOWERS AND DRIZZLE ON W FLOW. OF PACIFIC ORIGIN...THIS AIR MASS PALES IN COMPARISON TO ITS PREDECESSOR EARLIER THIS WEEK...THE OPPORTUNITY FOR SNOW ON THE BACKSIDE IS LIMITED TO THE HIGHEST TERRAIN...AS H85 TEMPERATURES ONLY GET DOWN TO -5C OR SO. THE WEAK PACIFIC HIGH PASSES S OF THE AREA SUN...WITH A RETURN TO S FLOW IN THE AFTERNOON. UPSLOPE FLOW WILL BE UT OFF AND CLEARING WILL ENSUE. TEMPERATURES RISE A BIT OVERNIGHT FRI NT AHEAD OF THE FRONT AND THEN START TO FALL A BIT SAT AFTERNOON BEHIND IT...USED MAINLY THE MET AND HAVE SMALLER DIURNAL RANGE THAN PREVIOUS. LOWS SAT NT LOOKED GOOD EVEN WITH THE QUICKER COLD ADVECTION. RAISED HIGHS SUN A BIT VIA THE BIAS CORRECTED MEX GIVEN FASTER CLEARING AND REVERSAL TO WARM ADVECTION COME SUN AFTERNOON. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE OF THE SE US WILL BRING A DRY START TO THE LONG TERM PERIOD. THERE IS POOR AGREEMENT BETWEEN THE ECMWF AND GFS ON SYSTEM ARRIVING LATE MONDAY. BOTH INDICATE A FRONTAL PASSAGE...BUT THE ECMWF ALSO SHOWS A SURFACE WAVE RIDING THE FRONT OUT OF THE SE...NORTHEAST JUST EAST OF THE APPALACHIANS. THE GFS DOES NOT HAVE THIS...AND IS INSTEAD JUST A COLD FRONTAL PASSAGE CONNECTED TO A SURFACE LOW NORTH OF THE GREAT LAKES. TRENDED TOWARD THE ECMWF...WHICH MESHES WELL WITH LATEST WPC GUIDANCE TOO. HAVE CHANCE POPS ACROSS WV ZONES WITH THE FRONT/SURFACE WAVE...SLIDE THOSE OUT TUESDAY. 500MB SHORTWAVE TROUGH PASSES WITH THE FRONT...WITH LARGER SCALE TROUGH ARRIVING MIDWEEK...BRINGING AN INCREASE IN POPS AGAIN TUESDAY NIGHT INTO WEDNESDAY. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... RADAR IMAGES INDICATE AN AREA OF SHOWERS MOVING FROM THE SOUTHWEST INTO WV AND SOUTHEAST OH OVERNIGHT. EXPECT MVFR CONDITIONS UNDER RAIN...MAINLY ALONG AND NORTH OF LINES FROM HTS TO CRW...AND CRW TO BKW AND ELEVATED TERRAIN. SOUTHWEST FLOW BRINGS WAA TO THE AREA...WHILE COLD AIR MASS REMAINS IN PLACE FAR NORTH OVER PORTIONS OF SOUTHEAST OH AND EXTREME NORTHERN WV. EXPECT SNOW MIXED WITH SLEET OR RAIN...OVERNIGHT TRANSITIONING TO ALL RAIN BY FRIDAY MORNING. SOUTH OF THE AFOREMENTIONED LINES PCPN SHOULD STAY ALL RAIN. BRIEF PERIODS OF IFR/MVFR CEILINGS EXPECTED AT BKW AFTER 09Z...AND ACROSS ALL SITES FRIDAY AFTERNOON AROUND 17Z. OTHERWISE...VFR/MVFR MIST AND RAIN EXPECTED FOR THE MOST PART ON FRIDAY. PCPN SHOULD START DIMINISHING FROM WEST TO EAST FROM 13Z TO 17 FRIDAY. FORECAST CONFIDENCE: HIGH UNTIL 06Z FRIDAY. MEDIUM. ALTERNATE SCENARIOS: TIMING AND ONSET OF PRECIP MAY VARY. PRECIP TYPE AND CIG CATEGORY MAY VARY FROM FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE FRI 01/10/14 UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12 CRW CONSISTENCY H M H H H H H H H H H H HTS CONSISTENCY M M H H H H M H H H H M BKW CONSISTENCY H H H H H H H H M M M M EKN CONSISTENCY H M M H H H H H H H H H PKB CONSISTENCY M M M M H H H H H H H H CKB CONSISTENCY H M M M H H H H H H H H AFTER 06Z SATURDAY... IFR CONDITIONS IN RAIN COULD DEVELOP SATURDAY INTO SUNDAY IN STRONG FLOW ALOFT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZING RAIN ADVISORY UNTIL 8 AM EST THIS MORNING FOR WVZ046- 047. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/MZ/26 NEAR TERM...ARJ/SL/26 SHORT TERM...TRM LONG TERM...MZ AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS TULSA OK
1123 PM CST THU JAN 9 2014 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. LIFR CONDITIONS WILL CONTINUE THROUGH EARLY FRIDAY MORNING IN MOST AREAS WITH INCREASING CHANCES OF LIGHT DRIZZLE OR RAIN OVER THE NEXT FEW HOURS. DEEPER MOISTURE SURGING NORTH AHEAD OF AN UPPER LEVEL SYSTEM WILL LEAD TO WIDESPREAD RAIN AFTER 12Z MAINLY ACROSS SE OK AND NW AR WITH SOME EMBEDDED THUNDER LIKELY THROUGH ABOUT 18Z. ONSET OF PRECIP WILL LIKELY CORRESPOND TO A SMALL IMPROVEMENT IN FLIGHT CONDITIONS...WITH FURTHER IMPROVEMENT TO MVFR AND FINALLY VFR LATE IN THE PERIOD AS A COLD FRONT SWEEPS THROUGH. && .PREV DISCUSSION... /ISSUED 915 PM CST THU JAN 9 2014/ ..UPDATE... DISCUSSION... A LOW CLOUD DECK WITH PATCHY AREAS OF REDUCED VIS CONTINUED ACROSS EASTERN OKLAHOMA AND NORTHWEST ARKANSAS THIS EVENING. THESE CONDITIONS HAVE KEPT TEMPS FROM CHANGING MUCH THROUGH THE EVENING HOURS...AND IN SOME PLACES...THE TEMP HAS COME UP A DEGREE OR SO. TEMPERATURES WILL CONTINUE TO HOVER CLOSE TO CURRENT READINGS INTO THE OVERNIGHT HOURS AND BEGIN SLOWLY WARMING DURING THE EARLY MORNING HOURS AS AN UPPER LEVEL SHORTWAVE AND ASSOCIATED COLD FRONT APPROACH THE REGION. THUS...LOW TEMPS TONIGHT WILL MORE THAN LIKELY BE REALIZED OVER THE NEXT FEW HOURS FOR MOST LOCATIONS. RAIN CHANCES WILL INCREASE LATE TONIGHT INTO FRIDAY FROM SOUTH TO NORTH WITH ALSO ISOLATED CHANCES FOR THUNDER AS THE WAVE APPROACHES. LATEST LOCAL MODEL AND HRRR HAVE BACKED OFF ON THE TIMING OF PRECIP SPREADING ACROSS THE REGION TONIGHT. THUS...HAVE BACKED OFF ON POPS SOME THROUGH 12Z FOR THE EVENING UPDATE... OTHERWISE THE REST OF THE CURRENT FORECAST FOR TONIGHT SEEMS TO BE HANDLING WELL. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...99 LONG TERM....99 AVIATION...14
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1152 PM CST THU JAN 9 2014 .UPDATE... UPDATED FOR THE 06Z AVIATION DISCUSSION. && .PREV DISCUSSION... /ISSUED 925 PM CST THU JAN 9 2014/ UPDATE... VISIBILITIES HAD DROPPED TO A LESS THAN 1 MILE NORTH OF JONESBORO THIS EVENING. THIS AREA WAS NORTH OF A WEAK SURFACE WARM FRONT THAT EXTENDED ROUGHLY ALONG INTERSTATE 40. HRRR AND GFS LAMP GUIDANCE SUGGEST WARM ADVECTION OVER THE NEARLY STATIONARY FRONT WILL DROP VISIBILITIES LOWER DURING THE OVERNIGHT. WITH TEMPS NEAR FREEZING...WILL NEED TO MONITOR TEMPS CLOSELY INTO THE EARLY OVERNIGHT. THEREAFTER...00Z NAM DEPICTS WARMING SURFACE TEMPS WITH WARM FRONT LIFTING THROUGH. HRRR DEPICTS ADDITIONAL AREAS OF FOG FORMING IN THE CLEAR SLOT OVER CENTRAL MS... AND SPREADING NORTH OVERNIGHT. FOR THE 9 PM UPDATE... HAVE KEPT THE MENTION OF DENSE FOG WEST OF THE MS RIVER... BUT DENSE FOG CANNOT BE RULED OUT EAST OF THE MS RIVER TOWARD MORNING...ASSOCIATED WITH A MARINE WARM FRONT LIFTING NORTH. PWB && .PREV DISCUSSION... /ISSUED 339 PM CST THU JAN 9 2014/ NEAR NORMAL TO SLIGHTLY ABOVE NORMAL TEMPERATURES EXPECTED OVER MUCH OF THE NEXT SEVEN DAYS. THE SHORTWAVE THAT HAS CAUSED THE WINTRY MIX AND RAIN TODAY IS PUSHING OUT OF THE MIDSOUTH. HOWEVER EXPECT SMALL CHANCES OF RAIN WILL CONTINUE TONIGHT INTO FRIDAY AS WARM AIR ADVECTION MAY PRODUCE SOME LIGHT SHOWERS ACROSS THE AREA. LOWS WILL ACTUALLY OCCUR THIS EVENING DUE TO THE WARM AIR ADVECTION TONIGHT. TEMPERATURES WILL SLOWLY RISE OVERNIGHT. THIS MEANS LOWS WILL BE AT OR ABOVE FREEZING TONIGHT WITH READINGS RANGING FROM THE LOWER 30S TO AROUND 40 DEGREES. HIGHS ON FRIDAY WILL BE IN THE 50S AND WILL FEEL GREAT AFTER THE EXTREME COLD THAT THE MIDSOUTH HAS EXPERIENCED. A COLD FRONT WILL MOVE THROUGH THE MIDSOUTH FRIDAY NIGHT. BETTER CHANCES FOR SHOWERS WILL OCCUR AS A RESULT. ALSO...CAN/T RULE OUT A FEW THUNDERSTORMS OCCURRING ACROSS NORTH MISSISSIPPI. DO NOT REALLY EXPECT MUCH IF ANY COOL DOWN AT ALL BEHIND THE FRONT AS IT IS MORE OF A PACIFIC ORIGIN FRONT THAN AN ARCTIC FRONT. HIGH PRESSURE WILL SETTLE OVER THE REGION FOR THE WEEKEND. A NICE WARMING TREND IS EXPECTED ON SUNDAY AS THE HIGH SHIFTS EAST AND WINDS TURN AROUND TO THE SOUTH. AS A RESULT...HIGHS WILL GET INTO THE LOWER TO MID 60S IN MANY LOCATIONS. A COLD FRONT WILL MOVE THROUGH SUNDAY NIGHT. THE GFS HAS LITTLE PRECIPITATION WITH THE FRONT WHILE THE ECMWF DEVELOPS A SFC LOW ALONG THE FRONT. AS A RESULT...THE MODEL PRODUCES QUITE A BIT OF QPF ACROSS THE AREA WITH BEST CHANCES OCCURRING ACROSS NORTHEAST MISSISSIPPI. HAVE TRIED TO GO WITH AN IN BETWEEN SOLUTION FOR NOW. HIGH PRESSURE WILL RETURN ON MONDAY AND MONDAY NIGHT. HOWEVER A REINFORCING FRONT WILL MOVE THROUGH ON TUESDAY AND WILL BRING COLDER AIR INTO THE AREA. HOW COLD THE AIR WILL BE DEPENDS ON WHICH MODEL YOU LOOK AT. THE ECMWF IS MUCH COLDER THAN THE GFS. AGAIN HAVE TRIED TO IN BETWEEN FOR TEMPERATURES FROM TUESDAY AND BEYOND AS RESULT OF THE DIFFERENT SOLUTIONS. HIGH PRESSURE WILL RETURN TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. ANOTHER COLD FRONT WILL APPROACH ON THURSDAY. KRM && .AVIATION... 06Z TAF CYCLE A WEAK SURFACE BOUNDARY REMAINS STRETCHED ACROSS SOUTHEAST ARKANSAS INTO WEST TENNESSEE ROUGHLY JUST NORTH OF THE I-40 CORRIDOR. LIFR OR LOWER CIGS AND REDUCED VSBYS PERSIST NORTH OF THE BOUNDARY AT KJBR AND SHOULD REMAIN IN PLACE THROUGH MUCH OF THE NIGHT. SOUTH OF THE BOUNDARY TO INCLUDE KMEM AND KMKL...LOW STRATUS HAS SCATTERED OUT WITH LIGHT SOUTHEAST WINDS AND A RETURN TO VFR CIGS/VSBYS EXPECTED UNTIL LATER TONIGHT. BEYOND 10Z...EXPECT LOW STRATUS AND FOG TO RETURN AS MOISTURE ADVECTS FROM THE SOUTH WITHIN WEAK ISENTROPIC ASCENT. LOW STRATUS WILL LIKELY INVADE KTUP WITHIN THE NEXT FEW HOURS ALONG WITH FOG DROPPING CIGS TO LIFR ALONG WITH REDUCED VSBYS. SCATTERED SHOWERS WILL BE POSSIBLE AS WELL OVERNIGHT AT KMEM AND KMKL WITH DRIZZLE POSSIBLE AT KJBR. CIGS SHOULD SLOWLY RISE WITH THE PASSAGE OF A SECONDARY WARM FRONT FRIDAY MORNING AT KMEM...KTUP...AND KMKL...BEFORE LOWERING AGAIN TOWARDS THE END OF THE PERIOD WITH THE APPROACH OF THE NEXT SHORTWAVE. FURTHER NORTH AT KJBR...CIGS AND VSBYS WILL STRUGGLE TO RISE AND SHOULD REMAIN QUITE LOW THROUGH THE TAF PERIOD. A PERIOD OF SHOWERS IS POSSIBLE WITH THE WARM FRONT IN THE MORNING AT KMEM...KTUP...AND KMKL. THERE SHOULD THEN BE A BREAK FOR A FEW HOURS BEFORE MORE RAIN DEVELOPS TOWARDS THE END OF THE PERIOD WITH APPROACHING SHORTWAVE FROM THE WEST. AT KJBR...RAIN CHANCES SHOULD CONTINUE THROUGH MUCH OF FRIDAY DUE TO CLOSE PROXIMITY OF THE FRONT AND EVENTUAL INFLUENCE FROM UPPER WAVE AS WELL BY AFTERNOON. WINDS SHOULD EVENTUALLY GO SOUTHERLY EVERYWHERE ON FRIDAY AND INCREASE IN SPEEDS WITH APPROACH OF WESTERN DISTURBANCE ALOFT. WIDESPREAD RAIN AND A FEW THUNDERSTORMS CAN BE EXPECTED AT ALL TERMINALS FRIDAY EVENING WITH IFR OR LOWER CIGS EXPECTED. JLH && .PRELIMINARY POINT TEMPS/POPS... MEM 42 57 45 57 / 30 50 100 10 MKL 39 56 46 56 / 20 40 100 10 JBR 34 50 36 52 / 30 70 100 10 TUP 46 58 52 62 / 20 30 100 20 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...DENSE FOG ADVISORY UNTIL 8 AM CST FRIDAY FOR CLAY-CRAIGHEAD- CRITTENDEN-CROSS-GREENE-LAWRENCE-MISSISSIPPI-POINSETT- RANDOLPH-ST. FRANCIS. MO...DENSE FOG ADVISORY UNTIL 8 AM CST FRIDAY FOR DUNKLIN-PEMISCOT. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
403 AM CST FRI JAN 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 402 AM CST FRI JAN 10 2014 AT 4 AM...A SHORT WAVE TROUGH WAS LOCATED OVER THE DAKOTAS. SOUTHERLY WINDS AND WARM AIR ADVECTION AHEAD OF THIS SYSTEM HAVE CAUSED THE TEMPERATURES TO SLOWLY RISE OVERNIGHT. VISIBILITIES HAVE DROPPED TO LESS THAN A MILE ACROSS MUCH OF NORTHEAST IOWA AND SOUTHEAST MINNESOTA. WE HAVE STARTED TO HEAR OF A FEW ACCIDENTS DUE TO THE SLICK ROADS. WHILE SOME OF THIS MOISTURE IS BEING DEPOSITED BY THE FOG AND THE REMAINDER OF IT IS BEING CAUSED BY THE DEW POINT TEMPERATURES CLIMBING ABOVE THE GROUND TEMPERATURE. WITH TEMPERATURES BELOW FREEZING THIS MOISTURE IS FREEZING. STILL DEBATING ON WHETHER TO ISSUE A FREEZING FOG ADVISORY OR A SPECIAL WEATHER STATEMENT. LIKE THE 09.18Z MODELS...WITH BOTH THE 270 AND 280K SHOWING VERY LITTLE LIFT THIS MORNING AND THE BUFKIT SOUNDINGS SHOWING SUBSIDENCE CO-LOCATED WITH THE LOW LEVEL MOISTURE...NOT EXPECTING MUCH PRECIPITATION THIS MORNING. DUE TO THIS...DRAMATICALLY LOWERED THE PRECIPITATION CHANCES FOR THIS MORNING. IF THERE IS ANY PRECIPITATION IT WILL BE IN THE FORM OF DRIZZLE OR FREEZING DRIZZLE. THIS PART OF THE FORECAST IS VERY TRICKY BECAUSE IT WILL BE HIGHLY DEPENDENT UPON HOW MUCH ARE THE ROADS ABLE TO WARM. DESPITE THE CLOUDS...THE SUN/S INFRARED RADIATION WILL CAUSE THE ROADS TO WARM UP. OVER THE PAST COUPLE OF DAYS...THE ROADS HAVE WARMED INTO THE MID AND UPPER 20S DURING THE AFTERNOON. THIS IS DESPITE THE VERY COLD AIR TEMPERATURES. WITH TEMPERATURES MUCH WARMER TODAY /LOWER TO MID 30S/...EXPECT THE UNSHELTERED ROADS TO WARM VERY CLOSE TO THE AIR TEMPERATURE. FOR THIS AFTERNOON AND EVENING...THE 10.00Z HAVE SHIFTED SOUTH WITH ITS 500 MB VORTICITY MAXIMUM. AS A RESULT...THE TRACK OF THE LOW PRESSURE SYSTEM AND ITS PRECIPITATION SHIFTED FURTHER TO THE SOUTHEAST. DESPITE THE WARM LAYER ALOFT COOLING ALOFT...THERE HAS ALSO BEEN A LOSS ICE ALOFT IN THE BUFKIT SOUNDINGS. THE -10C SURFACE SHOWS THAT THE RELATIVE HUMIDITIES FROM CHARLES CITY IOWA TO WAUSAU ARE AS LOW AS 70 PERCENT. AS A RESULT...EXPECT A BIT MORE LIQUID THAN SNOW WITH THIS SYSTEM. THIS MORE PROBLEMATIC LATE THIS AFTERNOON AND EVENING...BECAUSE WE WILL BE LOSING THE LONG RADIATION FROM THE SUN AND THIS WILL CAUSE THE MANY OF THE ROADS TO FALL QUICKLY BELOW FREEZING. DUE TO THE MIX PRECIPITATION AND A FURTHER SOUTHEAST SHIFT IN THE PRECIPITATION...LOWERED THE SNOW AMOUNTS INTO THE 1 TO 3 INCH RANGE. ICING WILL BE GENERALLY LESS THAN 5 HUNDREDTHS OF AN INCH. DUE TO THIS ICING...KEPT THE WINTER WEATHER ADVISORY GOING. FOR LATE TONIGHT...THE PRECIPITATION WILL BEGIN TO SHIFT EAST OF THE AREA. AS THIS OCCURS...BOTH THE BUFKIT SOUNDINGS AND -10C SURFACE SHOW THAT ICE WILL BE RETURNING TO THE AREA. AS A RESULT...EXPECT THAT PRECIPITATION WILL CHANGE OVER LIGHT SNOW BEFORE IT ENDS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 402 AM CST FRI JAN 10 2014 ON SATURDAY...A DEFORMATION BAND WILL PRODUCE SOME LIGHT SNOW MAINLY EAST OF THE MISSISSIPPI RIVER DURING THE MORNING. LITTLE... IF ANY...ACCUMULATION IS EXPECTED. ON SATURDAY NIGHT AND SUNDAY MORNING...A WARM FRONT WILL MOVE THROUGH THE REGION. 850 MB TEMPERATURES QUICKLY WARM TO AROUND 7C. SOUTHERLY WINDS IN THE WARM SECTOR OF THIS SYSTEM WILL ALLOW TEMPERATURES TO WARM INTO THE MID AND UPPER 30S. WHILE THE GEM GENERATES SOME PRECIPITATION AHEAD OF THIS FRONT...THE REMAINDER OF THE MODELS KEEP THE AREA DRY. AS A RESULT...WENT WITH A DRY FORECAST FOR THE AREA. ON SUNDAY NIGHT...A COLD FRONT MOVES THROUGH THE REGION. MUCH OF THE FORCING ASSOCIATED WITH THIS SYSTEM WILL REMAIN WELL NORTH OF THE FORECAST AREA. HOWEVER THERE APPEARS TO BE ENOUGH FRONTOGENESIS ALONG THIS FRONT TO PROVIDE ENOUGH LIFT TO WARRANT A SLIGHT CHANCE OF RAIN AND SNOW. ON MONDAY NIGHT AND TUESDAY...BOTH THE GFS AND ECMWF ARE SHOWING THAT A STRENGTHENING SHORT WAVE TROUGH WILL MOVE THROUGH NORTHEAST IOWA AND SOUTHERN WISCONSIN. WITH THIS BEING A NEW FEATURE IN THE MODELS...OPTED TO JUST ADD A SMALL CHANCE OF SNOW WITH IT. ON TUESDAY AND TUESDAY NIGHT...THE MODELS ARE NOW SHOWING STRONG COLD AIR ADVECTION DEVELOPING IN THE WAKE OF THE SHORT WAVE TROUGH. THIS DROPS THE 850 MB TEMPERATURES DOWN TO -10C. IF THIS VERIFIES...HIGH TEMPERATURES WILL REMAIN IN THE TEENS. SINCE THIS IS A NEW FEATURE...LOWERED THE TEMPERATURES BY 2 TO 3 DEGREES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1100 PM CST THU JAN 9 2014 IFR/MVFR CLOUDS HELD FAST ACROSS THE TAF SITES...AND WILL PERSIST THROUGH FRI NIGHT. EXPECTING SOME ADDITIONAL LOWERING ON FRI AS THE LOW SATURATION INCREASES AHEAD OF AN APPROACHING LOW. COULD BE SOME FZDZ EARLY FRI AFTERNOON WHEN CLOUD DEPTH AND SUFFICIENT LIFT COME TOGETHER. GRADUALLY...CLOUD DEPTH WILL DEEPEN ENOUGH FOR ICE IN THE CLOUD...AND SNOW. THIS LOOKS TO BE NEAR 00Z AT KRST/KLSE. EXPECTING SNOW ACCUMULATIONS OF 2 TO 4 INCHES...MOST OF WHICH WILL FALL FRI NIGHT. THINK THE THREAT FOR FZRA/PL IS LIMITED AT THIS TIME...BETTER CHANCES SOUTH/SOUTHEAST. WINDS WILL STAY SOUTHERLY THROUGH MUCH OF FRIDAY...BECOMING WEST/NORTHWEST AS THE LOW TRACKS INTO SOUTHERN WI FRI EVENING. INTERESTING NOTE FOR THIS EVENING...VERY FINE -SN HAS FALLEN FOR A FEW HOURS AT KRST. LATEST RAP SOUNDINGS INDICATE NEAR SFC TEMPS ARE NEAR -10 C...WHICH WOULD BE ENOUGH TO PRODUCE ICE CRYSTALS...AND IS THE LIKELY CAUSE FOR THE VERY LIGHT PCPN. IT WILL CONTRIBUTE TO VSBY REDUCTIONS...AND COULD MAKE RUNWAYS SLICK. CURRENT EXPECTATION IS THAT IT COULD LAST INTO THE OVERNIGHT HOURS...BUT SHOULD BE DONE BEFORE 12Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR WIZ017-029-034-041>044-053>055-061. MN...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR MNZ096. IA...WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR IAZ010-011-029-030. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1105 PM CST THU JAN 9 2014 .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT) ISSUED AT 324 PM CST THU JAN 9 2014 MAIN FORECAST CONCERNS CONTINUES FOCUSED ON THE STORM SYSTEM IMPACTING THE REGION FRIDAY THROUGH FRIDAY NIGHT WITH THE POTENTIAL FOR 2-5 INCHES OF SNOW AND A WINTRY MIX OF SNOW...FREEZING DRIZZLE/RAIN...AND SLEET. WATER VAPOR THIS AFTERNOON SHOWS SEVERAL EMBEDDED MID-LEVEL TROUGHS AFFECTING OR THAT WILL BE AFFECTING THE AREA. TROUGHS OVER MN/NORTHERN IL WERE SPREADING CLOUDS NORTHWARD INTO THE AREA. SOUTHERLY WINDS AHEAD ON THE MN TROUGH AND ON THE BACKSIDE OF SURFACE HIGH PRESSURE WAS HELPING TO BRING MODERATING TEMPERATURE OVER THE REGION. TEMPERATURES AT 2 PM WERE IN THE SINGLE DIGITS AND TEENS ABOVE ZERO. A MORE SIGNIFICANT MID-LEVEL WAVE WAS MOVING EAST OUT OF THE INTERMOUNTAIN WEST...WHICH WILL PRODUCE A WINTRY MIX/SNOWFALL ACROSS THE AREA FOR FRIDAY THROUGH FRIDAY NIGHT. FOR TONIGHT...WILL BE WATCHING THE WAVE COMING OUT OF THE INTERMOUNTAIN WEST INTO THE PLAINS. SOUTHERLY FLOW WILL AHEAD OF THIS TROUGH/WAVE WILL CONTINUE TO ADVECT MOISTURE AND CLOUD COVER INTO THE AREA. AS A RESULT...NOT LOOKING FOR MUCH TEMPERATURE DROP OFF. LOWS SHOULD BOTTOM OUT 3-5 DEGREES COOLER THAN THE HIGHS FROM TODAY...OR IN THE UPPER SINGLE DIGITS TO MIDDLE TEENS. ON FRIDAY...AS THE TROUGH CLOSES IN ON THE REGION AND AIDING IN LIFT ...LOOKING FOR A SMALL CHANCE FOR SOME FREEZING DRIZZLE IN THE MORNING. BUFKIT SOUNDINGS THEN SHOW THE COLUMN SATURATING UP TO AROUND 5KFT DURING THE AFTERNOON HOURS...DEEP ENOUGH FOR A DRIZZLE/RAIN MIX FOR PORTIONS OF THE AREA WITH LACK OF ICE IN THE CLOUD FOR MAKING SNOW. ALTHOUGH FORECASTING TEMPERATURES TO WARM INTO THE 32-35 DEGREE RANGE...FEEL THAT THE RECENT VERY COLD SNAP WILL KEEP ROAD TEMPERATURES SOMEWHERE IN THE MID-UPPER 20S. THIS WILL LIKELY LEAD TO SOME FREEZING RAIN...ESPECIALLY ALONG AND EAST OF THE MISSISSIPPI RIVER. AREAS WEST OF THIS LOOK TO HAVE ENOUGH ICE IN THE COLUMN FOR MORE SNOW. WILL LIKELY SEE ICE ACCUMULATIONS RANGING FROM A TRACE TO 0.05 INCH THROUGH MAINLY THE AFTERNOON//AGAIN MAINLY ALONG AND EAST OF THE MISSISSIPPI RIVER//...WITH A FEW TENTHS OF SNOWFALL WEST OF A WINONA MN TO CHARLES CITY LINE. LOOK FOR THE WINTRY MIX TO CHANGE OVER TO SNOW FRIDAY NIGHT...EXCEPT FOR AREAS OF NORTHEAST IA INTO FAR SOUTHWEST WI WHERE WARMER AIR ALOFT LINGERS A BIT LONGER. ALSO OF NOTE IS ALMOST ALL OF THE MODELS POINTING TOWARD A CLOSED/CLOSING MID-LEVEL LOW MOVING NORTHEAST ACROSS THE AREA FRIDAY NIGHT AND THE POTENTIAL FOR A STRONGER BAND OF 700-500MB FRONTOGENESIS/HEAVIER SNOWFALL FOR PORTIONS OF THE AREA. THE HIGHEST LIKELIHOOD OF THIS HAPPENING LOOKS TO BE IN AN AXIS FROM LA CROSSE AND BLACK RIVER FALLS ...INTO CENTRAL AND NORTHEAST WI. 2-5 INCHES OF SNOWFALL LOOKS LIKELY ACROSS OUR AREA IN THE AFOREMENTIONED AXIS. BASED ON THE WINTRY MIX AND LIKELIHOOD FOR 2-5 INCHES OF SNOWFALL...HAVE HOISTED A WINTER WEATHER ADVISORY FOR A PART OF NORTHEAST EAST IA AND PORTIONS OF SOUTHWEST INTO CENTRAL WI...IN EFFECT FROM NOON FRIDAY THROUGH FRIDAY NIGHT OR 12Z SATURDAY. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 324 PM CST THU JAN 9 2014 EXPECTING THE MID-LEVEL/SURFACE LOW TO PULL NORTHEAST OF THE AREA SATURDAY MORNING WITH PERHAPS SOME LINGERING LIGHT SNOW ALONG AND EAST OF THE MISSISSIPPI RIVER. LOOK FOR HIGHS ON SATURDAY IN THE UPPER 20S TO LOWER 30S...BUT INCREASING NORTHWEST WINDS ON THE BACKSIDE OF THE DEPARTING LOW WILL MAKE IT FEEL MORE LIKE THE TEENS TO LOWER 20S. A RIDGE OF HIGH PRESSURE WILL GIVE THE AREA A BRIEF QUIET PERIOD SATURDAY NIGHT WITH LOWS BOTTOMING OUT IN THE 10 TO 15 DEGREE RANGE. CLOUDS AND A CHANCE OF A WINTRY MIX WILL ENTER THE PICTURE AGAIN SUNDAY INTO SUNDAY NIGHT AS A COLD FRONT DROPS INTO THE REGION. EXPECTING HIGHS ON SUNDAY IN THE 30S IN ADVANCE OF THE COLD FRONT...AND THEN DROPPING INTO THE TEENS/LOWER 20S SUNDAY NIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1100 PM CST THU JAN 9 2014 IFR/MVFR CLOUDS HELD FAST ACROSS THE TAF SITES...AND WILL PERSIST THROUGH FRI NIGHT. EXPECTING SOME ADDITIONAL LOWERING ON FRI AS THE LOW SATURATION INCREASES AHEAD OF AN APPROACHING LOW. COULD BE SOME FZDZ EARLY FRI AFTERNOON WHEN CLOUD DEPTH AND SUFFICIENT LIFT COME TOGETHER. GRADUALLY...CLOUD DEPTH WILL DEEPEN ENOUGH FOR ICE IN THE CLOUD...AND SNOW. THIS LOOKS TO BE NEAR 00Z AT KRST/KLSE. EXPECTING SNOW ACCUMULATIONS OF 2 TO 4 INCHES...MOST OF WHICH WILL FALL FRI NIGHT. THINK THE THREAT FOR FZRA/PL IS LIMITED AT THIS TIME...BETTER CHANCES SOUTH/SOUTHEAST. WINDS WILL STAY SOUTHERLY THROUGH MUCH OF FRIDAY...BECOMING WEST/NORTHWEST AS THE LOW TRACKS INTO SOUTHERN WI FRI EVENING. INTERESTING NOTE FOR THIS EVENING...VERY FINE -SN HAS FALLEN FOR A FEW HOURS AT KRST. LATEST RAP SOUNDINGS INDICATE NEAR SFC TEMPS ARE NEAR -10 C...WHICH WOULD BE ENOUGH TO PRODUCE ICE CRYSTALS...AND IS THE LIKELY CAUSE FOR THE VERY LIGHT PCPN. IT WILL CONTRIBUTE TO VSBY REDUCTIONS...AND COULD MAKE RUNWAYS SLICK. CURRENT EXPECTATION IS THAT IT COULD LAST INTO THE OVERNIGHT HOURS...BUT SHOULD BE DONE BEFORE 12Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY FROM NOON FRIDAY TO 6 AM CST SATURDAY FOR WIZ017-029-034-041>044-053>055-061. MN...WINTER WEATHER ADVISORY FROM NOON FRIDAY TO 6 AM CST SATURDAY FOR MNZ096. IA...WINTER WEATHER ADVISORY FROM NOON FRIDAY TO 6 AM CST SATURDAY FOR IAZ010-011-029-030. && $$ SHORT TERM...DAS LONG TERM....DAS AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
544 AM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE CENTERED OFF THE NORTHEAST COAST WILL CIRCULATE MOIST AIR FROM THE ATLANTIC INTO THE FORECAST AREA AHEAD OF A COLD FRONT APPROACHING FROM THE WEST. THE FRONT WILL MOVE THROUGH THE AREA SATURDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MOISTURE ASSOCIATED WITH THE ONSHORE FLOW AND ISENTROPIC LIFT WILL BRING CLOUDINESS AND RAIN TODAY. THE 07Z HRRR MAINTAINS RAIN OVER MUCH OF THE AREA THROUGH TODAY. THE NAM AND TO SOME DEGREE THE GFS INDICATE DIMINISHING MOISTURE DURING THE AFTERNOON. THE NAM AND GFS MOS DISPLAY LOWER POPS THIS AFTERNOON COMPARED TO THE MORNING. THE NAM SHOWS AN H7 SHORTWAVE TROUGH LIFTING NORTH OF THE AREA AFTER 18Z WITH MOISTURE BECOMING MORE SHALLOW BEHIND THIS FEATURE. FORECASTED LOWER POPS DURING THE AFTERNOON...BUT NOT AS LOW AS THE NAM AND GFS MOS BECAUSE OF THE HRRR. CONFIDENCE IS LOW WITH THE TEMPERATURE FORECAST. WE USED THE COOLER TEMPERATURE GUIDANCE BECAUSE OF THE WEDGE PATTERN BUT MOISTURE BECOMING MORE SHALLOW BEHIND THE SHORTWAVE TROUGH MAY LEAD TO BREAKS IN THE CLOUDINESS AND WARMER TEMPERATURES. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... THE NAM AND GFS SHOW MOISTURE SOMEWHAT SHALLOW WITH LITTLE ISENTROPIC LIFT TONIGHT. USED THE GUIDANCE CONSENSUS AND FORECASTED CHANCE POPS. HIGH LOW-LEVEL MOISTURE AND DIURNAL COOLING PLUS CONVERGENCE NEAR THE WEDGE/WARM FRONT SHOULD HELP SUPPORT FOG TONIGHT. DENSE FOG MAY OCCUR. THE NAM AND GFS MOS PLUS SREF GUIDANCE INDICATE FOG. THE MOISTURE INCREASE ASSOCIATED WITH THE STRONG H85 JET AND LIFT WITH THE RIGHT ENTRANCE REGION OF THE H25 JET PLUS CONVERGENCE ALONG THE COLD FRONT SUPPORT CATEGORICAL POPS SATURDAY. THE NAM...GFS...AND SREF MEAN DISPLAY RAIN AMOUNTS AROUND 0.6 OF AN INCH. THERE MAY BE ENOUGH INSTABILITY FOR THUNDERSTORMS. THE NAM INDICATES SURFACE-BASED LI/S -2 TO -3. THE INSTABILITY IS QUESTIONABLE BECAUSE IT SHOULD BE LIMITED BY CLOUDINESS AND FOG. HOWEVER...IF SURFACE-BASED INSTABILITY DOES DEVELOP THEN DAMAGING WIND MAY OCCUR WITH ANY THUNDERSTORMS BECAUSE OF STRONG SHEAR. THE NAM AND GFS HAVE H85 WINDS OF 50 TO 60 KNOTS. DRYING WILL OCCUR BEHIND THE FRONT SATURDAY NIGHT. WE USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST THROUGH THE PERIOD EXCEPT THE COOLER GUIDANCE MAY BE BETTER SATURDAY BECAUSE OF CLOUDINESS AND SHOWERS. && .LONG TERM /SUNDAY THROUGH THURSDAY/... THE GFS AND ECMWF SHOW DRY RIDGING DOMINATING SUNDAY INTO MONDAY. THE MODELS DISPLAY MOISTURE ASSOCIATED WITH A COLD FRONT MONDAY NIGHT AND TUESDAY MORNING. THE ECMWF SHOWS A STRONGER SYSTEM AND ITS MOS HAS LIKELY POPS. WE KEPT CHANCE POPS FOR NOW AS GIVEN BY THE GFS AND EKD MOS PLUS GFS ENSEMBLE MEAN. EXPECT A REINFORCING COLD FRONT WITH LIMITED MOISTURE WEDNESDAY. ABOVE NORMAL TEMPERATURES SHOULD OCCUR SUNDAY THROUGH TUESDAY...WITH NEAR OR BELOW NORMAL READINGS BEHIND THE FRONT BY THURSDAY. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... HIGH PRESSURE CONTINUES TO MOVE AWAY FROM THE REGION AS LOW PRESSURE DEVELOPS OVER THE CENTRAL PLAINS. SOUTHEASTERLY LOW LEVEL WINDS CONTINUE TO PUSH MOISTURE INTO THE AREA WITH WSR-88D RETURNS INDICATING LIGHT RAIN ACROSS THE AREA. RAIN WILL CONTINUE INCREASING IN COVERAGE OVERNIGHT INTO FRIDAY MORNING AS ISENTROPIC ASCENT PERSISTS. CIGS WILL BE THE MAIN CONCERN THROUGH THE PERIOD WITH CIGS LOWERING TO AROUND 800 FEET BY 09Z...WITH FURTHER LOWERING TO AROUND 500 FEET FROM 11/01Z THROUGH THE END OF THE TAF PERIOD. EXPECT RAIN TO REMAIN LIGHT THROUGH 15-17Z WHEN THE BEST MOISTURE FLUX SHIFTS NORTHWARD AND RAIN DIMINISHES. WINDS THROUGH THE PERIOD WILL BE NORTHEASTERLY AT 6 KNOTS OR LESS. EXTENDED AVIATION OUTLOOK...INCREASING CONFIDENCE IN CIG RESTRICTIONS SATURDAY THROUGH SATURDAY NIGHT...WITH INCREASING CHANCES OF SHOWERS SATURDAY MORNING AS A COLD FRONT APPROACHES. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
645 AM EST FRI JAN 10 2014 .SYNOPSIS... ISSUED AT 420 AM EST FRI JAN 10 2014 SOME PATCHY DRIZZLE OF FREEZING DRIZZLE CAN BE EXPECTED THIS MORNING AS AN UPPER LEVEL DISTURBANCE SHIFTS EAST OF THE AREA. A STRONGER UPPER LEVEL DISTURBANCE WILL CONTINUE TO TAKE SHAPE ACROSS THE PLAINS TODAY AND WILL TRACK EASTWARD TONIGHT BRINGING WIDESPREAD RAIN TO THE AREA. RAIN WILL TAPER FROM WEST TO EAST LATE TONIGHT INTO EARLY SATURDAY. HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE MID AND UPPER 30S ACROSS CENTRAL LOWER MICHIGAN TO THE LOWER TO MID 40S FROM CENTRAL INDIANA INTO WEST CENTRAL OHIO. LOW TEMPERATURES TONIGHT WILL DROP INTO THE MID AND UPPER 30S FOR MOST LOCATIONS...WITH LOWER 40S ACROSS WEST CENTRAL OHIO. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 420 AM EST FRI JAN 10 2014 BRIEF LULL IN MEASURABLE PRECIP IS SETTING UP THIS MORNING AS STRONGEST DPVA WITH COMPACT SHORT WAVE HAS SHIFTED INTO NORTHWEST OHIO...AND THIS FORCING WILL QUICKLY TRANSLATE EASTWARD THIS MORNING OUT OF THE FORECAST AREA. REDUCED STATIC STABILITY IN THE MID LEVELS AND STEEP MID/UPPER LEVEL LAPSE RATES HAVE ALLOWED SECONDARY BLOSSOMING OF RADAR RETURNS PAST FEW HOURS ACROSS FAR SOUTHEAST PORTIONS OF THE AREA. HOWEVER...DRIER MID LEVEL AIR IS ALREADY ADVECTING ACROSS THESE LOCATIONS WITH RAP SHORT TERM BUFFER SOUNDINGS INDICATING TRANSITION TO MORE OF A LIGHT FREEZING DRIZZLE PRECIP TYPE. WEAK UPPER LEVEL SHORT WAVE RIDGING/SUBSIDENCE WILL CONTINUE TO BUILD INTO THE AREA FOR A SHORT TERM THIS MORNING WITH ONLY VERY SHALLOW AND WEAK VERTICAL MOTIONS THIS MORNING. SECONDARY LOW LEVEL ISENTROPIC SURGE APPEARS TO BE TAKING SHAPE ACROSS CENTRAL INDIANA WITH SECONDARY WARM FRONT...AND REGIONAL RADAR MOSAIC/SFC OBS HAVE BEEN INDICATING INCREASING -DZ/-FZDZ ACROSS CENTRAL INDIANA. EXPECTING DRIZZLE TO INCREASE IN COVERAGE TOWARD 12Z ACROSS THE AREA WITH NEAR SFC WET BULBS VERY MARGINAL IN TERMS OF SUPPORTING DRIZZLE OR FREEZING DRIZZLE...PARTICULARLY ACROSS THE FAR SOUTH. WILL KEEP -FZDZ MENTION GOING THIS MORNING AND HAVE MAINTAINED NATURE OF PREVIOUS FORECAST IN SOUTH TO NORTH EVOLUTION THROUGH THE MORNING HOURS OF TRANSITION FROM -FZDZ TO -DZ. WITH LOW CONFIDENCE IN EXTENT/INTENSITY OF ANY FZDZ THIS MORNING AND INCREASING MARGINAL LOW LEVEL WET BULB PROFILES WILL HOLD OFF ON ANY HEADLINES AND CONTINUE MENTION IN MORNING HWO. OTHERWISE A MILDER DAY IN STORE ALTHOUGH SOLID SNOWPACK ACROSS THE AREA WILL LIMIT EXTENT OF SFC WARMUP WITH WAA...WITH HIGHS GENERALLY FROM MID 30S TO AROUND 40. FOG ALSO EXPECTED TO BECOME MORE PREVALENT TODAY FROM SOUTHWEST TO NORTHEAST WITH LOW LEVEL MOISTURE ADVECTION OVER SNOWPACK. FOCUS FOR THE REMAINDER OF THE SHORT TERM WILL THEN SHIFT TO INCREASING RAIN POTENTIAL LATER THIS AFTERNOON INTO TONIGHT ALONG WITH POTENTIAL HYDROLOGIC IMPACTS. WATER VAPOR IMAGERY EARLY THIS MORNING DEPICTS DIGGING UPPER TROUGH APPROACHING THE CENTRAL PLAINS WITH SECONDARY WEAKER SHORT WAVE APPROACHING WEST TEXAS. MODEL GUIDANCE HAS BEEN FAIRLY CONSISTENT IN MAINTAINING AN UNPHASED NATURE WITH THESE TWO SHORT WAVES...QUICKLY TAKING THE WEST TEXAS VORT MAX INTO THE WESTERN GREAT LAKES THIS EVENING. BROAD WARM/MOIST ADVECTION TO OCCUR TODAY...WITH MORE FOCUSED AXIS OF DEEPER MOISTURE SETTING UP IN VICINITY OF LOW/MID LEVEL CONFLUENCE ZONE ACROSS THE WESTERN GREAT LAKES. HAVE CONTINUED UPWARD TREND TO CATEGORICAL POPS FOR LATE THIS AFTERNOON ACROSS APPROXIMATELY WESTERN THIRD OF THE AREA WITH PERIODS OF MODERATE RAIN EXPECTED IN THE 21Z-03Z TIMEFRAME. ON HEELS OF THIS LEAD WAVE...EXPECTING LARGER SCALE FRONTAL RESPONSE TO INCREASE ACROSS THE MID MS RIVER VALLEY EARLY THIS EVENING IN ADVANCE OF MORE AMPLIFIED CENTRAL PLAINS TROUGH. A STRONG LLJ WILL VEER THIS EVENING IN ADVANCE OF THIS TROUGH AND SHOULD ADVECT PRIMARY LOW LEVEL THERMAL/MOIST AXIS ACROSS SERN PORTIONS OF THE FORECAST AREA LATER THIS EVENING INTO THE OVERNIGHT HOURS. PREFRONTAL CONVERGENCE AXIS SHOULD BE PROGRESSIVE ACROSS THE AREA SO CONFIDENCE SOMEWHAT LOW ON EXACT RAINFALL AMOUNTS ACROSS SOUTHEAST OF THE AREA WITH POTENTIAL OF HEAVIEST AMOUNTS REMAINING JUST TO EAST AND SOUTHEAST. HAVE MADE VERY FEW CHANGES TO PREVIOUS FORECAST WITH RAINFALL AMOUNTS IN THE HALF INCH TO INCH RANGE. IN ADDITION TO THIS RAIN...EXISTING SNOWPACK DOES CONTAIN 1 TO 2 INCHES OF LIQUID EQUIVALENT...WITH 2+ INCHES ACROSS THE FAR NORTH ACROSS SOUTHERN LOWER MICHIGAN. STILL SOME UNCERTAINTY AS TO EXTENT/TIMING OF RUNOFF FROM RAIN/SNOWMELT GIVEN FLUCTUATING SFC TEMPS OVER THE NEXT FEW DAYS. IF HIGHER END OF FORECASTED RAINFALL AMOUNTS DO OCCUR...PORTIONS OF MAUMEE AND WABASH RIVER BASINS STILL APPEAR TO STAND GREATEST RISK OF MINOR FLOODING OVER NEXT FEW DAYS GIVEN WARMER LOW LEVEL PROFILES AND GREATER RUNOFF FROM SNOWMELT. ACROSS THE FAR NORTH WHERE GREATER LIQUID EQUIVALENT IN SNOWPACK EXISTS...CONFIDENCE REMAINS SOMEWHAT LOWER IN TERMS OF EXTENT/TIMING OF SNOWMELT GIVEN COOLER LOW LEVEL TEMPS ACROSS THESE LOCATIONS. HOWEVER...GIVEN MORE FAVORABLE TRACK WITH INITIAL SHORT WAVE THIS EVENING...SOME LOCALLY HIGHER RAINFALL AMOUNTS ARE POSSIBLE TONIGHT ACROSS ESPECIALLY WESTERN PORTIONS OF ST. JOSEPH BASIN. WILL CONTINUE WITH ESF THIS MORNING TO DISCUSS POSSIBLE HYDRO IMPACTS OVER THE NEXT SEVERAL DAYS. && .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 420 AM EST FRI JAN 10 2014 VORT MAX WILL BE SWEEPING ACROSS THE CWA AT THE START OF THE PERIOD...WITH RAIN QUICKLY SHIFTING WEST TO EAST DURING THE MORNING HOURS AS COLD FRONT USHERS IN A QUICK SHOT OF COOLER AIR. THIS WILL ALLOW A BRIEF PERIOD FOR RAIN/SNOW MIX ACROSS THE AREA. HOWEVER...BY THIS POINT DEEPEST MSTR AND LIFT WILL BE SHIFTING EAST...KEEPING ANY ACCUMULATION POTENTIAL TO A MINIMUM. PREV FORECAST GENERALLY LEFT INTACT. 925 MB TEMPS WILL BOTTOM OUT AROUND -5 C BY LATE SAT NGT...TRANSLATING TO LOWS IN THE MID TO UPR 20S...STILL A GOOD 10 DEGREES OR MORE ABOVE NORMAL FOR MID JANUARY. UPPER LEVEL RIDGING WILL QUICKLY MOVE BACK IN BY SUNDAY WITH RETURN TO ABOVE NORMAL TEMPS IN TO THE 30S AND POSSIBLY LOW 40S WITH EFFECTS OF SNOWPACK BEING GREATLY REDUCED. TEMPS WILL STAY ABOVE FREEZING INTO MONDAY IN ADVANCE OF YET ANOTHER NORTHERN STREAM TROUGH TO BRING A CHANCE OF RAIN. A FEW OF THE MODELS SHOW POTENTIAL INTERACTION WITH SOUTHERN STREAM ENERGY BUT EVEN THE STRONGEST ECMWF ONLY SHOWS A SHARPENING OF THE PROGRESSIVE TROUGH. STATUS QUO FOR THE TIME BEING MON/MON NGT WITH CHC POPS AS BEST POTENTIAL REMAINS N AND S OF THE AREA. ACTIVE PATTERN CONTINUES WITH OVERALL LONGWAVE TROUGH REMAINING IN PLACE ACROSS THE GREAT LAKES WITH A STRONGER WAVE DROPPING THROUGH FOR MID WEEK. MODELS DIVERGE EVEN FURTHER WITH ECMWF CLOSING OFF A PROGRESSIVE UPPER LOW OVER THE CAROLINAS BY WEDNESDAY EVENING. WILL KEEP CONSERVATIVE LOW END POPS IN N AREAS THURSDAY AS MAIN TROUGH MOVES IN. TEMPERATURES WILL HOVER EITHER SIDE OF NORMAL WITH WARM UPS AHEAD OF EACH WAVE AND DROP TO SLIGHTLY BELOW NORMAL BEHIND IT. SOME INDICATIONS OF RETURN OF COLDER...BELOW NORMAL AIR OUTSIDE THE PERIOD BUT BY FAR MUCH WARMER THAN RECENT POLAR BLAST. FLOODING CONCERNS WILL LIKELY LINGER THROUGH MUCH OF THE PERIOD...BUT EXACT MAGNITUDE WILL BE TRICKY TO SORT OUT AS MUCH OF IT WILL FOCUS ON QPF OVER THE NEXT DAY OR SO. WILL CONTINUE WITH HWO MENTION INTO MID WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 622 AM EST FRI JAN 10 2014 THE SHORT WAVE WHICH BROUGHT SNOW TO THE AREA LAST EVENING HAS EXITED TO THE EAST. DRY MID LEVEL AIR IN THE WAKE OF THIS SHORT WAVE AND CONTINUED WEAK LOW LEVEL LIFT HAS ALLOWED FOR PATCHY DRIZZLE/FREEZING DRIZZLE TO FORM ACROSS NORTHERN INDIANA. INTENSITY OF THIS PRECIP WILL REMAIN VERY LIGHT THIS MORNING WITH MOISTURE DEPTH INCREASING THIS AFTERNOON IN ADVANCE OF A STRONGER UPPER LEVEL DISTURBANCE KICKING OUT OF THE PLAINS. WIDESPREAD RAIN IS EXPECTED TO DEVELOP LATE AFTERNOON ACROSS NWRN INDIANA AND SPREAD EASTWARD ACROSS NORTHERN INDIANA EARLY THIS EVENING. CONTINUED LOW LEVEL WARM/MOISTURE ADVECTION THROUGH THE PERIOD OVER EXISTING SNOWPACK WILL OFFER LITTLE OPPORTUNITY TO IMPROVE IFR/LIFR CONDITIONS THROUGH THIS FORECAST PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MARSILI SHORT TERM...MARSILI LONG TERM...FISHER AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
940 AM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE MOVES OFFSHORE TODAY AND TONIGHT AS A SERIES OF WEAK UPPER LEVEL TROUGHS TRACK ACROSS THE MID ATLANTIC REGION. A COLD FRONT APPROACHES FROM THE WEST SATURDAY AND PUSHES THROUGH THE REGION SATURDAY NIGHT EVENING. HIGH PRESSURE RETURNS FROM THE WEST LATER SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... QUICK UPDATE TO REFLECT EXPIRATION OF FZRA ADVISORY. WHILE AWOS/MESONET DATA REFLECT THAT TEMPS ARE AOA32 DEG ACROSS THE AREA, WE HAVE HAD SEVERAL REPORTS OF LIGHT FZRA/ICY ROAD CONDITIONS FROM EARLIER THIS MORNING ACROSS THE NOW EXPIRED ADVY AREA. DID ISSUE AN SPS TO REFLECT SOME LINGERING ICY PATCHES ACROSS THIS SAME AREA NW OF RIC METRO THROUGH LATE MORNING. OTHERWISE...NO CHANGES NEEDED ATTM. UPDATED PREV DISCUSSION...ISSUED 718 AM EST THE LATEST SURFACE ANALYSIS INDICATES A ~1036MB SFC HIGH PRESSURE CENTERED OFF CAPE COD...WITH A SFC RIDGE AXIS EXTENDING SW ALONG THE PIEDMONT INTO NE GA...AND A COASTAL TROUGH NOW PRESENT OVER THE NC COASTAL PLAIN INTO SE VA. THE LATEST REGIONAL RADAR MOSAIC INDICATES AN AREA OF WARM ADVECTION EXTENDING FROM THE SOUTHERN APPALACHIANS TO THE MID ATLANTIC. THE HRRR AND RUC BOTH SHOW MOISTURE CONTINUING TO STREAM OVER THE AREA THROUGH THE DAY. WARM/MOIST ADVECTION CONTINUES TODAY. THE SHORTWAVE TROUGH RESPONSIBLE FOR THE MORNING PRECIP LIFTS TO THE NE THIS MORNING. HOWEVER...ANOTHER MID-LEVEL WAVE LIFTS ACROSS THE REGION IN SSW FLOW ALOFT THIS AFTERNOON. THIS WILL BRING ANOTHER ROUND OF RA TO PRIMARILY CENTRAL PORTIONS OF THE AREA LATER THIS AFTERNOON. HIGH TEMPERATURES WILL VARY FROM AROUND 40 NW TODAY WITH A CAD WEDGE IN PLACE...TO NEAR 60 SE AS THE COASTAL FRONT MOVES INLAND. WEAK FLOW AND ABUNDANT MOISTURE BELOW 700MB WILL RESULT IN OVERCAST CONDITIONS THROUGHOUT TODAY. TEMPERATURES SHOULD FALL VERY LITTLE TONIGHT (AND LIKELY RISE TOWARD SATURDAY MORNING) AS THE SURFACE WARM FRONT LIFTS THROUGH THE AREA...RESULTING IN WIDESPREAD STRATUS AND OCCASIONAL -RA/DZ. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... THE TROUGH PRESENTLY DIGGING FROM THE INTERMOUNTAIN WEST TOWARD THE HIGH PLAINS PER GOES WATER VAPOR IMAGERY WILL CONTINUE TO AMPLIFY ACROSS THE CENTRAL CONUS TODAY. INCREASINGLY ZONAL FLOW OVER THE WESTERN US EVENTUALLY PUSHES THE TROUGH AXIS ACROSS THE APPALACHIANS BY SAT/SAT EVENING. ASIDE FROM SUBTLE TIMING DIFFERENCES...GEFS/SREF ENSEMBLE GUIDANCE ALONG WITH DETERMINISTIC ECMWF/GFS/NAM/CMC NOW DEMONSTRATE DECENT AGREEMENT WITH THIS SYSTEM. THERE IS A HIGH CONFIDENCE OF MEASURABLE RAIN IN THE SAT/SAT EVENING TIMEFRAME. DEEP MOISTURE THROUGH 300MB COMBINED WITH STRONG LIFT SHOULD PRODUCE MODERATE TO OCCASIONALLY HEAVY RA. HOWEVER...QPF SHOULD LARGELY AVG 0.75-1.00IN DUE TO THE QUICK MOTION OF THE SYSTEM. TEMPERATURES SHOULD BE VERY MILD AS THE SURFACE WARM FRONT LIFTS N OF THE LOCAL AREA AND 850MB TEMPERATURE SURGE TO 10-12C. FORECAST HIGHS FROM THE MID 60S TO AROUND 70 WILL BE MAINTAINED FOR MUCH OF THE FORECAST AREA. THERE IS STILL SOME UNCERTAINTY WITH RESPECT TO TEMPERATURE OVER NW PORTIONS...AS THERE IS A POSSIBILITY THAT A MODIFIED WEDGE AIRMASS MAY REMAIN LOCKED IN...WHICH COULD KEEP HIGHS IN THE 50S. BREEZY CONDITIONS DEVELOP FOR THE EASTERN THIRD OF THE AREA...WITH A S WIND OF 15-20MPH WITH GUSTS TO AROUND 30MPH. 10/03Z SREF PROBS CONTINUE TO INDICATE A 90% CHANCE OF 2M DEWPOINTS EXCEEDING 60F ACROSS S-CENTRAL/SE VA AND NE NC...AND 10/00Z NAM INDICATES STRONG UPRIGHT FRONTOGENESIS FROM THE SURFACE TO ~850MB...WHICH ENHANCES LOW-LEVEL VERTICAL ASCENT. THIS IS PROGGED TO OCCUR IN A SYNOPTIC ENVIRONMENT FEATURING 65-70KT 850-700MB LAYER AVG SSW WIND...50-60KT OF SW 0-6KM BULK SHEAR...AND 250-500 J/KG ML CAPE. GIVEN THE COMBINATION OF SYNOPTIC AND MESOSCALE FACTORS...THERE IS AN INCREASING PROB FOR A FORCED LINE OF CONVECTION (RARE BUT NOT UNPRECEDENTED FOR JAN) CAPABLE OF PRODUCING STRONG TO POTENTIALLY DAMAGING WIND GUSTS...MAINLY ACROSS S-CENTRAL/SE VA AND NE NC. BASED ON THE LATEST DATA...THE TIMING OF THE GREATEST THREAT WOULD BE FROM SAT AFTERNOON INTO EARLY EVENING. A TRANSITION DAY ON SUNDAY AS UPPER TROUGH PIVOTS OFFSHORE AND QUASI-ZONAL FLOW BRING A CLEARING AND STILL-MILD DAY. HIGHS GENERALLY IN THE 50S TO NEAR 60. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... STAYING CLOSE TO THE 12Z ECMWF FOR THE EXTENDED PERIOD. HI PRES WILL SLIDE OFF THE CST AND OUT TO SEA SUN NGT THRU MON...PROVIDING MSTLY CLEAR/PARTLY TO MOSTLY SUNNY CONDITIONS ACRS THE AREA. LATE MON NGT THRU TUE...THE LATEST ECMWF BRINGS A SRN STREAM LO AND A COLD FRONT TWD/AND ACRS THE AREA LATE MON NGT THRU TUE. AT THIS TIME...HAVE SLGT CHC (20) POPS THEN CHC (30) POPS OVR THE REGION. THE FRONT PUSHES OUT TO SEA TUE EVENG...BUT A SECONDARY BOUNDARY MAY CROSS THE AREA ON WED. HAVE KEPT A DRY FCST FOR WED AT THIS TIME. DRIER AND COOLER WNW FLO FILTERS IN FOR WED NGT THRU THU...AS HI PRES BLDS INTO AND OVR THE REGION. MIN TEMPS WILL RANGE THRU THE 30S MON MORNG...IN THE UPR 30S TO MID 40S TUE MORNG...IN THE 30S WED MORNG...AND IN THE MID 20S TO LWR 30S THU MORNG. MAX TEMPS WILL RANGE FM THE MID 50S TO LWR 60S MON...IN THE 50S TUE...IN THE MID 40S TO LWR 50S WED...AND IN THE 40S THU. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... -RA WILL BEGIN TO SPREAD INTO WESTERN PORTIONS OF THE FA AROUND DAYBREAK...AFFECTING KRIC BY 11Z-12Z. MVFR CONDITIONS WILL THEN OVERSPREAD THE ENTIRE AREA BY LATE MORNING...AND LIKELY CONTINUES INTO TONIGHT. BEST CHANCE FOR IFR CONDITIONS WILL BE AT KRIC. OUTLOOK...A MORE ORGANIZED FRONTAL SYSTEM APPROACHES THE REGION ON SATURDAY...WITH PERIODS OF RAIN AND WIDESPREAD MVFR/OCNL IFR CONDITIONS AND GUSTY WINDS. LOOK FOR DRY AND VFR CONDITIONS SUNDAY AND MONDAY THEN DETERIORATING CONDS ONCE AGAIN AROUND TUESDAY. && .MARINE... HIGH PRESSURE MOVES OFF THE NEW ENGLAND COAST TODAY...AS A TROF OF LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST. E WINDS 10 KT OR LESS THIS MORNING WILL BECOME SE 10-15 KT BY EVENING. SE WINDS WILL THEN INCREASE TO 15 TO 20 KT LATE TONIGHT BEFORE BECOME S AND INCREASING TO 15 TO 25 KT AND GUSTY FOR SAT...AS A WARM FRONT LIFTS NWRD THRU THE AREA...FOLLOWED BY THE APPROACH OF A COLD FRONT. HAVE ISSUED SCA`S BEGINNING EARLY SAT MORNING FOR ALL WATERS BASED ON GOOD AGREEMENT IN MODELS FOR GUSTY WINDS DURING SAT INTO SAT NIGHT... ALONG WITH SEAS BUILDING TO 5-9 FT. GALE FORCE WINDS ARE NOT EXPECTED ATTM EXCEPT POSSIBLY IN A NARROW BAND OF CONVECTION THAT MAY MOVE THRU WITH THE COLD FRONT LATE SAT. THIS CAN LIKELY BE HANDLED WITH SPECIAL MARINE WARNINGS AS OPPOSED TO A SHORT DURATION GALE WARNING. S-SW WINDS SAT INTO SAT EVE WILL VEER TO THE WNW AND REMAIN GUSTY BEHIND THE FRONT SAT NIGHT INTO SUN MORNING...THEN SETTLE DOWN AND BECOME SW LATE SUNDAY AS HIGH PRESSURE BUILDS IN. ANOTHER ROUND OF UNSETTLED CONDITIONS IS POSSIBLE BY TUESDAY. && .CLIMATE... RECORD HIGH TEMPERATURES SATURDAY JANUARY 11 RIC 72/1975 ORF 75/1974 SBY 68/1975 ECG 75/1974 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ635>638. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ630>634-650-652-654-656-658. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ SHORT TERM...AJZ/MAM LONG TERM...TMG AVIATION...JDM MARINE...JDM CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
718 AM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE MOVES OFFSHORE TODAY AND TONIGHT AS A SERIES OF WEAK UPPER LEVEL TROUGHS TRACK ACROSS THE MID ATLANTIC REGION. A COLD FRONT APPROACHES FROM THE WEST SATURDAY AND PUSHES THROUGH THE REGION SATURDAY NIGHT EVENING. HIGH PRESSURE RETURNS FROM THE WEST LATER SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... THE LATEST SURFACE ANALYSIS INDICATES A ~1036MB SFC HIGH PRESSURE CENTERED OFF CAPE COD...WITH A SFC RIDGE AXIS EXTENDING SW ALONG THE PIEDMONT INTO NE GA...AND A COASTAL TROUGH NOW PRESENT OVER THE NC COASTAL PLAIN INTO SE VA. THE LATEST REGIONAL RADAR MOSAIC INDICATES AN AREA OF WARM ADVECTION EXTENDING FROM THE SOUTHERN APPALACHIANS TO THE MID ATLANTIC. THE HRRR AND RUC BOTH SHOW MOISTURE CONTINUING TO STREAM OVER THE AREA THROUGH THE DAY. MODEL THICKNESSES AND BUFKIT SOUNDINGS INDICATE THE POTENTIAL FOR A LIGHT MIX (MAINLY NW A LINE FROM DAN-OFP-BWI) EARLY THIS MORNING...WHICH IS SUPPORTED BY REGIONAL OBS OVER THE CENTRAL VA PIEDMONT. BASED ON LATEST FORECAST SOUNDINGS...EXPECT LIGHT PRECIP TO BEGIN AS SLEET/IP...BEFORE TRANSITIONING QUICKLY TO FZRA. ANY QPF WILL BE VERY LIGHT (LESS THAN 0.10IN). HOWEVER...CONSIDERING THE TIMING OF ANY LGT PRECIP COINCIDING WITH THE EARLY PORTION OF THE MORNING RUSH...A SHORT DURATION FZRA ADVISORY WILL REMAIN IN AFFECT OVER THE PIEDMONT NW OF RIC METRO THROUGH 14Z. OF NOTE...MECKLENBURG AND LUNENBURG COUNTIES HAVE BEEN REMOVED FROM THE ADVISORY AS CURRENT OBSERVATIONAL DATA AND MODEL DATA DOES NOT SUPPORT THE POTENTIAL FOR EVEN MINOR ICING. POINTS FARTHER EAST...SUCH AS THE NORTHERN NECK AND INTERIOR LOWER MD EASTERN SHORE COULD EXPERIENCE SOME IP AT THE ONSET. HOWEVER...THERE IS LITTLE SUPPORT FOR ICING IN THESE LOCATIONS. ANY LINGERING FZRA THIS MORNING SHOULD TRANSITION TO RA AFTER 9 AM THIS MORNING. WARM/MOIST ADVECTION CONTINUES TODAY. THE SHORTWAVE TROUGH RESPONSIBLE FOR THE MORNING PRECIP LIFTS TO THE NE THIS MORNING. HOWEVER...ANOTHER MID-LEVEL WAVE LIFTS ACROSS THE REGION IN SSW FLOW ALOFT THIS AFTERNOON. THIS WILL BRING ANOTHER ROUND OF RA TO PRIMARILY CENTRAL PORTIONS OF THE AREA LATER THIS AFTERNOON. HIGH TEMPERATURES WILL VARY FROM AROUND 40 NW TODAY WITH A CAD WEDGE IN PLACE...TO NEAR 60 SE AS THE COASTAL FRONT MOVES INLAND. WEAK FLOW AND ABUNDANT MOISTURE BELOW 700MB WILL RESULT IN OVERCAST CONDITIONS THROUGHOUT TODAY. TEMPERATURES SHOULD FALL VERY LITTLE TONIGHT (AND LIKELY RISE TOWARD SATURDAY MORNING) AS THE SURFACE WARM FRONT LIFTS THROUGH THE AREA...RESULTING IN WIDESPREAD STRATUS AND OCCASIONAL -RA/DZ. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... THE TROUGH PRESENTLY DIGGING FROM THE INTERMOUNTAIN WEST TOWARD THE HIGH PLAINS PER GOES WATER VAPOR IMAGERY WILL CONTINUE TO AMPLIFY ACROSS THE CENTRAL CONUS TODAY. INCREASINGLY ZONAL FLOW OVER THE WESTERN US EVENTUALLY PUSHES THE TROUGH AXIS ACROSS THE APPALACHIANS BY SAT/SAT EVENING. ASIDE FROM SUBTLE TIMING DIFFERENCES...GEFS/SREF ENSEMBLE GUIDANCE ALONG WITH DETERMINISTIC ECMWF/GFS/NAM/CMC NOW DEMONSTRATE DECENT AGREEMENT WITH THIS SYSTEM. THERE IS A HIGH CONFIDENCE OF MEASURABLE RAIN IN THE SAT/SAT EVENING TIMEFRAME. DEEP MOISTURE THROUGH 300MB COMBINED WITH STRONG LIFT SHOULD PRODUCE MODERATE TO OCCASIONALLY HEAVY RA. HOWEVER...QPF SHOULD LARGELY AVG 0.75-1.00IN DUE TO THE QUICK MOTION OF THE SYSTEM. TEMPERATURES SHOULD BE VERY MILD AS THE SURFACE WARM FRONT LIFTS N OF THE LOCAL AREA AND 850MB TEMPERATURE SURGE TO 10-12C. FORECAST HIGHS FROM THE MID 60S TO AROUND 70 WILL BE MAINTAINED FOR MUCH OF THE FORECAST AREA. THERE IS STILL SOME UNCERTAINTY WITH RESPECT TO TEMPERATURE OVER NW PORTIONS...AS THERE IS A POSSIBILITY THAT A MODIFIED WEDGE AIRMASS MAY REMAIN LOCKED IN...WHICH COULD KEEP HIGHS IN THE 50S. BREEZY CONDITIONS DEVELOP FOR THE EASTERN THIRD OF THE AREA...WITH A S WIND OF 15-20MPH WITH GUSTS TO AROUND 30MPH. 10/03Z SREF PROBS CONTINUE TO INDICATE A 90% CHANCE OF 2M DEWPOINTS EXCEEDING 60F ACROSS S-CENTRAL/SE VA AND NE NC...AND 10/00Z NAM INDICATES STRONG UPRIGHT FRONTOGENESIS FROM THE SURFACE TO ~850MB...WHICH ENHANCES LOW-LEVEL VERTICAL ASCENT. THIS IS PROGGED TO OCCUR IN A SYNOPTIC ENVIRONMENT FEATURING 65-70KT 850-700MB LAYER AVG SSW WIND...50-60KT OF SW 0-6KM BULK SHEAR...AND 250-500 J/KG ML CAPE. GIVEN THE COMBINATION OF SYNOPTIC AND MESOSCALE FACTORS...THERE IS AN INCREASING PROB FOR A FORCED LINE OF CONVECTION (RARE BUT NOT UNPRECEDENTED FOR JAN) CAPABLE OF PRODUCING STRONG TO POTENTIALLY DAMAGING WIND GUSTS...MAINLY ACROSS S-CENTRAL/SE VA AND NE NC. BASED ON THE LATEST DATA...THE TIMING OF THE GREATEST THREAT WOULD BE FROM SAT AFTERNOON INTO EARLY EVENING. A TRANSITION DAY ON SUNDAY AS UPPER TROUGH PIVOTS OFFSHORE AND QUASI-ZONAL FLOW BRING A CLEARING AND STILL-MILD DAY. HIGHS GENERALLY IN THE 50S TO NEAR 60. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... STAYING CLOSE TO THE 12Z ECMWF FOR THE EXTENDED PERIOD. HI PRES WILL SLIDE OFF THE CST AND OUT TO SEA SUN NGT THRU MON...PROVIDING MSTLY CLEAR/PARTLY TO MOSTLY SUNNY CONDITIONS ACRS THE AREA. LATE MON NGT THRU TUE...THE LATEST ECMWF BRINGS A SRN STREAM LO AND A COLD FRONT TWD/AND ACRS THE AREA LATE MON NGT THRU TUE. AT THIS TIME...HAVE SLGT CHC (20) POPS THEN CHC (30) POPS OVR THE REGION. THE FRONT PUSHES OUT TO SEA TUE EVENG...BUT A SECONDARY BOUNDARY MAY CROSS THE AREA ON WED. HAVE KEPT A DRY FCST FOR WED AT THIS TIME. DRIER AND COOLER WNW FLO FILTERS IN FOR WED NGT THRU THU...AS HI PRES BLDS INTO AND OVR THE REGION. MIN TEMPS WILL RANGE THRU THE 30S MON MORNG...IN THE UPR 30S TO MID 40S TUE MORNG...IN THE 30S WED MORNG...AND IN THE MID 20S TO LWR 30S THU MORNG. MAX TEMPS WILL RANGE FM THE MID 50S TO LWR 60S MON...IN THE 50S TUE...IN THE MID 40S TO LWR 50S WED...AND IN THE 40S THU. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... -RA WILL BEGIN TO SPREAD INTO WESTERN PORTIONS OF THE FA AROUND DAYBREAK...AFFECTING KRIC BY 11Z-12Z. MVFR CONDITIONS WILL THEN OVERSPREAD THE ENTIRE AREA BY LATE MORNING...AND LIKELY CONTINUES INTO TONIGHT. BEST CHANCE FOR IFR CONDITIONS WILL BE AT KRIC. OUTLOOK...A MORE ORGANIZED FRONTAL SYSTEM APPROACHES THE REGION ON SATURDAY...WITH PERIODS OF RAIN AND WIDESPREAD MVFR/OCNL IFR CONDITIONS AND GUSTY WINDS. LOOK FOR DRY AND VFR CONDITIONS SUNDAY AND MONDAY THEN DETERIORATING CONDS ONCE AGAIN AROUND TUESDAY. && .MARINE... HIGH PRESSURE MOVES OFF THE NEW ENGLAND COAST TODAY...AS A TROF OF LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST. E WINDS 10 KT OR LESS THIS MORNING WILL BECOME SE 10-15 KT BY EVENING. SE WINDS WILL THEN INCREASE TO 15 TO 20 KT LATE TONIGHT BEFORE BECOME S AND INCREASING TO 15 TO 25 KT AND GUSTY FOR SAT...AS A WARM FRONT LIFTS NWRD THRU THE AREA...FOLLOWED BY THE APPROACH OF A COLD FRONT. HAVE ISSUED SCA`S BEGINNING EARLY SAT MORNING FOR ALL WATERS BASED ON GOOD AGREEMENT IN MODELS FOR GUSTY WINDS DURING SAT INTO SAT NIGHT... ALONG WITH SEAS BUILDING TO 5-9 FT. GALE FORCE WINDS ARE NOT EXPECTED ATTM EXCEPT POSSIBLY IN A NARROW BAND OF CONVECTION THAT MAY MOVE THRU WITH THE COLD FRONT LATE SAT. THIS CAN LIKELY BE HANDLED WITH SPECIAL MARINE WARNINGS AS OPPOSED TO A SHORT DURATION GALE WARNING. S-SW WINDS SAT INTO SAT EVE WILL VEER TO THE WNW AND REMAIN GUSTY BEHIND THE FRONT SAT NIGHT INTO SUN MORNING...THEN SETTLE DOWN AND BECOME SW LATE SUNDAY AS HIGH PRESSURE BUILDS IN. ANOTHER ROUND OF UNSETTLED CONDITIONS IS POSSIBLE BY TUESDAY. && .CLIMATE... RECORD HIGH TEMPERATURES SATURDAY JANUARY 11 RIC 72/1975 ORF 75/1974 SBY 68/1975 ECG 75/1974 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR VAZ048- 049-060>064-067>069. MARINE...SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ630>634-650-652-654-656-658. SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ635>638. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ SHORT TERM...AJZ/MAM LONG TERM...TMG AVIATION...JDM MARINE...JDM CLIMATE...AJZ
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
532 AM CST FRI JAN 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 338 AM CST FRI JAN 10 2014 THE RAP HAS ANALYZED A H500 MB SHORT WAVE ACROSS ERN WYOMING THIS MORNING. THE PV15 ANOMALY EXTENDS FROM KCYS SOUTH THROUGH KDEN. IF THE RAP AND THE OTHER MODELS ARE CORRECT THEN SCATTERED SNOW SHOWERS SHOULD DEVELOP ACROSS NW NEB IN A FEW HOURS AND MOVE SOUTHEAST THROUGH SWRN AND SCNTL NEB. THE ONGOING RADAR RETURNS ACROSS NERN COLO ARE RAIN AND THE SNOW SHOWERS SHOULD DEVELOP ONCE THE THERMAL RIDGE ACROSS SWRN NEB MOVES EAST LATER THIS MORNING. OTHERWISE...THE ARCTIC DRAPE WILL MOVE EAST OF THE FCST AREA IN A FEW HOURS AHEAD THE SHORT WAVE AND ALL OF THIS WEATHER SHOULD EXIT THE FCST AREA TO THE EAST BY 21Z PROVIDING FOR A PARTLY SUNNY AFTERNOON WITH HIGHS IN THE UPPER 30S TO MID 40S. FOR TONIGHT...A WEAK COLD FRONT WILL BE PRESSING INTO NRN NEBRASKA TOWARD MORNING. THERE IS VERY LITTLE THERMAL RIDGING AHEAD OF THE FRONT AND H850 WINDS INCREASE FROM 25 TO 35 KT FRIDAY EVENING TO 40 TO 50 KT BY SATURDAY MORNING. ALL OF THIS SUGGESTS...GIVEN THE GENERALLY CLEAR SKIES TONIGHT...LOWS IN THE 20S MOST AREAS WITH TEENS IN THE PLATTE VALLEY AND CUSTER COUNTY. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 338 AM CST FRI JAN 10 2014 LITTLE CHANGE TO THE OVERALL PATTERN WITH A RIDGE IN THE WEST AND A TROUGH IN THE EAST...AND NORTHWEST FLOW ACROSS THE HIGH PLAINS. SEVERAL WEAK TROUGHS/CLIPPERS WILL PUSH ACROSS THE PLAINS...WITH A SLIGHT WARM UP AHEAD OF THE SYSTEM...AND A SLIGHT COOL DOWN WITH AN INCREASE OF CLOUDS WITH EACH TROUGH. WARM AIR ARRIVES FOR SATURDAY AHEAD OF THE NEXT TROUGH HIGHS NEARING THE MID 50S FOR THE SW AS 850 MB TEMPS PUSH TO AROUND 10 C. COOLER OVER N CENTRAL...MID 40S WITH 850 MB TEMPS CLOSER TO ZERO. SATURDAY NIGHT INTO SUNDAY THE TROUGH WILL CROSS THE CWA. MIXING ALONG AHEAD OF THE TROUGH WILL PUSH TEMPS BACK TO AROUND 50...WITH THE NW HOLDING CLOSER TO 40. THERE IS A CHANCE FOR SOME VERY LIGHT PRECIP /FLURRIES OR SPRINKLES/ ALTHOUGH LOW CONFIDENCE. MODELS HAVE SEVERAL MARGINAL POSITIVES TO LIGHT PRECIP...HOWEVER THEY ARE NOT OVERLAPPING. THE NW ZONES HAS THE STEEPEST LAPSE RATES HOWEVER THE RIGHT ENTRANCE TO A JET STREAK FAVORS THE SW. LL MOISTURE IS LIMITED AND MODELS VARY WITH POCKETS OF LOWER CONDENSATION DEFICITS...LESS THAN 20 MB. BY SUNDAY EVENING TROUGH AXIS IS EAST AND ANY LIGHT PRECIP WILL HAVE ENDED. MONDAY THE RIDGE RETURNS LATE IN THE DAY...AND HIGHS SHOULD REBOUND LATE TO AROUND 50 SW TO MID 50S N. BY MONDAY NIGHT A WEAK UPPER LEVEL DISTURBANCE TO RIDE THE NW FLOW. BETTER ENERGY IS ACROSS THE NORTHERN PLAINS...HOWEVER MAY GET SOME LIGHT SNOW ACROSS THE NW...WHERE MODELS HAVE A LITTLE UPPER LEVEL SUPPORT FROM THE LEFT EXIT REGION OF THE NEXT JET STREAK. THIS WILL WEAK SYSTEM WILL QUICKLY PASS TO THE EAST ON TUESDAY...ALTHOUGH SOME LINGERING CLOUDS EARLY ON IN THE DAY MAY LIMIT HEATING AND FOLLOWED SLIGHT COOL DOWN FROM THE DAY BEFORE...PER GUIDANCE. AS SYSTEM DIGITS ACROSS THE GREAT LAKES REGION/MID ATLANTIC FOR WEDNESDAY...RIDGE EXPANDS ACROSS THE WEST. MODELS IN GOOD AGREEMENT WITH ANOTHER SURGE OF WARMER AIR ACROSS THE HIGH PLAINS. HIGHS ONCE AGAIN INTO THE MID AND UPPER 50S FOR SW NEB AND UPPER 40S ELSEWHERE. THIS WARM AIR WILL BE AHEAD OF THE NEXT CLIPPER WHICH SHOULD ARRIVE WED NIGHT. THIS WILL BRING ANOTHER COOL DOWN FOR THURSDAY. ONE COMMON THEME THROUGH THE END OF THE WEEKEND INTO NEXT WEEK WILL BE BREEZY TO WINDY CONDITIONS. FAST MOVING SYSTEMS ARE STEERED BY SWIFT WINDS ALOFT AND WITH HIGHS ABOVE SEASONAL AVERAGES...GOOD MIXING WILL TAP INTO THE STRONGER WINDS. DAY TIME SFC WINDS OF 15 TO 30 MPH...WITH HIGHER GUSTS...CAN BE EXPECTED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 531 AM CST FRI JAN 10 2014 THE LIFR AT KLBF COULD IMPROVE TO VFR AT ANY TIME GIVEN THE NORTHWEST WINDS AT KOGA. THE MODELS DEVELOP SCATTERED SNOW SNOWERS THIS MORNING THROUGH EARLY AFTN. THIS MAY NOT VERIFY AS THE BEST FORCING IS CURRENTLY MOVING THROUGH NERN COLO/SWRN NEB AND VFR IS WIDESPREAD ACROSS NWRN NEB AND ERN WY WHERE THE MODELS EXPECT THE SNOW SHOWERS TO DEVELOP. THERE ARE RADAR RETURNS SHOWING IN THE THESE AREAS HOWEVER SO COVERAGE COULD BE ISOLATED VS THE SCATTERED COVERAGE FORECAST. VFR IS EXPECTED 21Z THROUGH 06Z. THEREAFTER...MVFR CIGS MAY INVADE THE AREA FROM NORTH TO SOUTH AS ANOTHER COLD FRONT MOVES INTO NRN NEB. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
646 AM EST FRI JAN 10 2014 .SYNOPSIS...MOISTURE INCREASES OVER THE REGION TODAY AS HIGH PRESSURE MOVES EAST INTO THE ATLANTIC. A STRONG COLD FRONT SWEEPS ACROSS THE REGION SATURDAY. HIGH PRESSURE BUILDS BACK IN ON SUNDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 305 AM FRIDAY... WATER VAPOR IMAGERY SHOWS AT LEAST MODEST MID-LEVEL SHORTWAVES MOVING TOWARD CENTRAL NORTH CAROLINA FROM THE SOUTHWEST...WHILE THE 00Z UPPER-AIR INFORMATION NOTED INCREASING 700MB AND 850MB MOISTURE UPSTREAM...AND 500MB DIFFLUENCE JUST TO OUR WEST. WITH THE APPROACH OF THE SHORTWAVES...MODEL FORECAST LIFT INCREASES AS WELL...WITH MODEST UPPER-LEVEL DIFFLUENCE TAKING PLACE FOR MUCH OF THE DAY. GUIDANCE POPS ARE HIGH...AND CURRENTLY THIS SEEMS REASONABLE GIVEN THE AVAILABLE SYNOPTIC LIFT AND INCREASING MOISTURE. THE VARIETY OF WRF GUIDANCE IS BULLISH ON PRECIPITATION CHANCES AS WELL...WITH THE LATEST HRRR WRF NOTING LIKELY CHANCES FOR PRECIPITATION AS FAR EAST AS THE NORTHEAST COASTAL PLAIN EARLY THIS AFTERNOON. WILL FORECAST BASICALLY CATEGORICAL CHANCES FOR RAIN TODAY MAINLY ALONG AND WEST OF U.S. 1...AND ESSENTIALLY LIKELY CHANCES EAST OF THERE. THE LATEST SPC MESOANALYSIS SHOWED THE WET-BULB ZERO LINE NORTH OF CENTRAL NORTH CAROLINA...BASICALLY NEAR OR NORTH OF THE VIRGINIA BORDER COINCIDENT WITH THE PIEDMONT...AND IN MANY AREAS THE SURFACE DEW POINT WAS APPROACHING...OR EVEN ABOVE...30 DEGREES. THE IMMEDIATE TRIAD HAD DEW POINTS STILL AROUND 20...BUT GIVEN THE KEXX DEW POINT ABOVE 32...AND TEMPERATURES IN THE TRIAD AROUND 40...THINK THE POTENTIAL FOR ANY FREEZING PRECIPITATION IS VERY SLIM AND THIS FORECAST WILL CONTINUE TO BE ALL LIQUID. TEMPERATURES TODAY WILL BE SOMEWHAT CHALLENGING...BUT WITH THE CLOUD COVER AND PRECIPITATION MOVING IN FROM THE SOUTHWEST...IT MAY BE DIFFICULT FOR MUCH OF A RISE. WILL KEEP IN MIND...THOUGH...THAT TEMPERATURES IN MANY LOCATIONS ARE AT LEAST AROUND 40...AND IN THE MID 40S IN PARTS OF THE SANDHILLS AND SOUTHERN COASTAL PLAIN. WILL STILL LIKELY HEDGE TOWARD THE COOLER SIDE OF GUIDANCE...OR A BLEND SUCH AS TOWARD THE TRIAD WHERE THE MET 39 MAY BE TOO COOL BUT THE MAV 46 MAY BE TOO WARM GIVEN THE EXPECTED NORTHEAST FLOW AND MORE AREAS OF RAIN THROUGHOUT THE DAY. STILL...A GOOD TEMPERATURE RANGE ANTICIPATED FROM AROUND 40 TO THE LOWER 40S NORTHWEST...TO THE LOWER 60S TOWARD KCTZ. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/... AS OF 645 AM FRIDAY... TONIGHT...THE BETTER LIFT THAT IS FORECAST BY THE GFS TODAY MOVES OFF TO THE EAST...BEFORE BETTER LIFT TAKES PLACE AGAIN ALONG AND IN ADVANCE OF THE STRONG COLD FRONT TO MOVE THROUGH SATURDAY. GFS BUFR SOUNDINGS SHOW THE LOW-LEVELS REMAINING FAIRLY SATURATED ACROSS CENTRAL NORTH CAROLINA...AS 850MB WINDS START TO INCREASE OVERNIGHT. WHILE 850MB THETA-E VALUES INCREASE STEADILY TODAY INTO THIS EVENING...THE GFS DOES FORECAST A PERIOD OF DECREASING 850MB THETA-E LATE TONIGHT INTO EARLY SATURDAY MORNING. IT IS IN THIS SAME PERIOD WHERE THE STATISTICAL GUIDANCE SHOWS A SHORT DIMINISHING TREND IN CHANCES FOR RAIN...AND THE CONSENSUS OF WRF GUIDANCE NOTES LESSER COVERAGE OF PRECIPITATION. THE CURRENT THINKING IS THAT SCATTERED TO NUMEROUS AREAS OF RAIN AND DRIZZLE THROUGH THE EVENING AND INTO THE OVERNIGHT HOURS MAY BECOME MORE ISOLATED TO SCATTERED LATE TONIGHT...POSSIBLY INCREASING AGAIN TOWARD THE YADKIN RIVER VERY LATE TONIGHT INTO EARLY SATURDAY IN GOOD ISENTROPIC LIFT ON THE 295K AND 300K SURFACES. OVERNIGHT LOWS MAY OCCUR EARLY BEFORE TEMPERATURES SLOWLY INCREASE DURING THE NIGHT. ONCE AGAIN WILL LEAN TOWARD A BLEND OF THE GUIDANCE IN THE TRIAD WHERE THERE IS THE LARGEST DISCREPANCY BETWEEN THE MAV AND THE MET...AND RIGHT NOW MAINLY ON THE COOLER SIDE ELSEWHERE THOUGH...AS NOTED...READINGS SHOULD GRADUALLY RISE OVERNIGHT. NOTED IN THE RECENT FORECAST UPDATE PATCHY FOG PARTICULARLY IN THE WEST AND NORTHWEST PIEDMONT MAINLY THIS EVENING. IN THE COOLER AREAS...AS MOISTURE INCREASES AND BEFORE SURFACE WINDS START TO INCREASE LATER AT NIGHT...PATCHY FOG COULD RESULT. THE SREF PROBABILISTIC GUIDANCE SUGGESTS A HIGH PROBABILITY OF VISIBILITIES LESS THAN ONE MILE IN MANY AREAS WEST OF U.S. 1 THROUGH THE OVERNIGHT HOURS...BUT CURRENTLY THINK IF THE WINDS START TO INCREASE IN SPEED THIS COULD LIMIT SOME OF THE LATE NIGHT FOG POTENTIAL. THIS WILL BE ASSESSED FURTHER DURING THE DAY. SATURDAY INTO SATURDAY NIGHT...PRECIPITATION CHANCES INCREASE SOLIDLY WITH THE APPROACH AND PASSAGE OF THE FRONT. HEIGHT FALLS ALOFT SHOULD BE STRONG AS WELL AS THE MID-LEVEL TROUGH APPROACHES FROM THE WEST LATE IN THE DAY SATURDAY. INSTABILITY IS NOT GREAT BASED ON THE MODEL SOUNDING LAPSE RATES AND THE MIXED-LAYER CAPE FORECAST ON THE GFS IN THE LOWEST KM. IN FACT...THE MLCAPE REGISTERS ONLY TOWARD THE FAR SOUTHEAST...FROM ABOUT KMEB TO KGSB OR SO... WITH VALUES OF 500J/KG OR LESS. INTERESTINGLY...THOUGH...DOWNDRAFT CAPE INCREASES NOTICABLY ALONG AND NORTH OF U.S. 64 DURING THE AFTERNOON TO VALUES AROUND 700J/KG. EVEN THOUGH THE GFS BUFR SOUNDINGS SHOW THE MIXED LAYER TO BE FAIRLY SHALLOW SATURDAY AFTERNOON...WHERE THERE IS EVEN A BIT OF INSTABILITY...WINDS ALOFT INCREASE RAPIDLY TO 40 TO 50KT. THUNDER...OVERALL...MAY BE SOMEWHAT DIFFICULT TO COME BY...BUT GIVEN THE 40 TO 50KT 925MB WINDS IN THE AFTERNOON...AND 60 TO 70KT AT 850MB ALONG WITH GOOD THICKNESS PACKING AS THE FRONT MOVES THROUGH...A STRONGLY-FORCED LINE OF SHOWERS COULD TAKE PLACE RESULTING IN GUSTY WINDS. WILL NOTE THE POTENTIAL FOR STRONG TO SEVERE CONDITIONS IN THE HWO FOR SATURDAY... MAINLY IN THE AFTERNOON AND...FOR THE MOST PART...EAST OF THE FAR WESTERN PIEDMONT. MAV GUIDANCE FOR HIGHS SATURDAY ARE WARM...AND AT KRDU ARE ONLY A COUPLE OF DEGREES SHY OF THE RECORD. FOR NOTE... HIGH TEMPERATURE RECORDS ARE 73 AT KGSO IN 1949...AND 73 AT KRDU AND 79 AT KFAY IN 1930. ONCE AGAIN...WILL CURRENTLY PLAN A FORECAST WITH A BLEND OF THE MAV AND MET MOS. DRYING TAKES PLACE SATURDAY NIGHT AND THE CHANCES FOR PRECIPITATION DIMINISH WEST TO EAST AS K INDICES GO MOSTLY NEGATIVE BY 12Z SUNDAY. GUSTY WINDS IN THE EVENING DIMINISH SOME OVERNIGHT...AND THE APPROACH OF THE STRONG TROUGH ALOFT COULD LINGER CLOUDS AND SOME RAIN CHANCES THROUGH THE EVENING...AND INTO THE EARLY PART OF THE OVERNIGHT HOURS EAST OF U.S. 1. OVERNIGHT LOWS AROUND 40 TO THE MID 40S. && .LONG TERM /SUNDAY THROUGH THURSDAY/... AS OF 305 AM FRIDAY... THE LONG WAVE TROUGH AXIS WILL BE EXITING THE EAST COAST EARLY SUNDAY...WITH INCREASING HEIGHTS ACROSS OUR REGION THROUGH THE DAY. AT THE SURFACE...A HIGH PRESSURE CENTER WILL QUICKLY MOVE FROM THE NORTHERN GULF COAST AT 12Z SUNDAY TO A POSITION OFF THE SE COAST BY 00Z MONDAY. FOR OUR SENSIBLE WEATHER...SUBSIDENCE AND SUBSEQUENT DRYING WILL YIELD MOSTLY SUNNY SKIES DURING THE DAY. LOW LEVEL THICKNESSES...WHILE EXPECTED TO BOTTOM OUT AROUND 1305M EARLY IN THE DAY BEHIND THE DEPARTING TROUGH...WILL INCREASE TO AROUND 1330M BY LATE AFTERNOON. THUS LOOK FOR HIGHS TO RANGE FROM THE MID 50S NW TO LOWER 60S SE. SUNDAY NIGHT...THE MID/UPR RIDGE AXIS WILL BE TO OUR EAST AND THE NEXT TROUGH WILL BE MOVING ACROSS THE PLAINS. INCREASING SW FLOW ALOFT WILL RESULT IN THICKENING MID/HI CLOUDS ACROSS OUR AREA. LOWS IN THE MID-UPR 30S. MONDAY WILL SEE INCREASING CLOUDS AHEAD OF THE AFOREMENTIONED TROUGH...WHICH WILL BE CROSSING THE MISS RIVER VALLEY BY 00Z TUESDAY. HIGHS WILL CLIMB WELL ABOVE NORMAL IN THE PRE-FRONTAL AIRMASS. HIGHS IN THE LOWER 60S. THEN...SUBSTANTIAL DIFFERENCES CONTINUE IN THE LATEST GFS AND ECMWF RUNS REGARDING THE TIMING AND STRENGTH OF THE PROGRESSIVE BUT DAMPENING SHORT WAVE PROGGED TO LIFT NE AND ACROSS OUR AREA MONDAY NIGHT (PER GFS) OR LATE MONDAY NIGHT AND DURING THE DAY TUESDAY (PER ECMWF). THE ECMWF IS THE WETTER OF THE TWO THANKS TO ITS STRONGER SHORT WAVE AND MUCH-STRONGER (COMPARED TO GFS) LOW LEVEL JET AND MOISTURE TRANSPORT...THUS SHOWING AROUND 1/2 INCH QPF. IF THE TRENDS GO THE ECMWF WAY WITH FUTURE RUNS...WILL ALSO NEED TO KEEP A CLOSE EYE ON THERMAL PROFILES AND THE POTENTIAL FOR CONVECTION ON TUESDAY ALONG AND AHEAD OF THE COLD FRONT. BY LATE TUESDAY...THE COLD FRONT WILL BE TO OUR EAST...WITH SUBSIDENCE...CAA...AND DRYING IN IT`S WAKE. WE`LL THEN TURN OUR ATTENTION TO THE NEXT SHORT WAVE PROGGED TO DROP SE ACROSS THE MIDWEST AND OH VALLEY TUESDAY NIGHT. THE GFS AND ECMWF ARE IN DECENT AGREEMENT EARLY WITH THIS SYSTEM WHILE IT`S UPSTREAM OF US...BUT THEN START TO DIFFER QUITE DRAMATICALLY AS THE WAVE BOTTOMS OUT ACROSS THE CAROLINAS. THE ECMWF IS MUCH SLOWER AND CLOSES OFF THE MID LEVEL WAVE AS IT CROSSES THE CAROLINAS AND RESULTS IN SFC CYCLOGENESIS JUST OFF THE COAST. THE GFS ON THE OTHER HAND IS MUCH FASTER WITH AN OPEN WAVE THAT QUICKLY MOVES ACROSS AND EXITS OUR AREA. WHILE FORECAST SOUNDINGS AND PARTIAL THICKNESSES FROM BOTH SUGGEST THAT THE AIRMASS WILL LIKELY BE COLD ENOUGH FOR A MIX OF RAIN/SNOW OR ALL SNOW...BOTH SOLUTIONS ARE RATHER MOISTURE-STARVED WITH NO GULF AND VERY LITTLE ATLANTIC MOISTURE...UNTIL THE SYSTEM IS TO OUR EAST. SO FOR NOW...WILL KEEP POPS WITH THIS SYSTEM LIMITED TO CLIMO VALUES. THIS NW FLOW SYSTEM APPEARS TO BE THE LOWER-IMPACT TYPE THAT RESULTS IN PERHAPS A FEW FLURRIES...OR PERHAPS A BRIEF SNOW SHOWER OR TWO...WHICH WOULD OCCUR LATE WEDNESDAY OR WEDNESDAY NIGHT. THEN FOR THE LATTER HALF OF THE WEEK...THURSDAY LOOKS DRY WITH A SHORTWAVE RIDGE CROSSING THE AREA...THEN ANOTHER MOISTURE-STARVED SHORTWAVE TROUGH IS PROGGED TO MOVE ACROSS UNEVENTFULLY BY WEEKS END. MEX TEMPS LOOK TOO HIGH FOR THE LATTER HALF OF NEXT WEEK GIVEN LOW LEVEL THICKNESSES...THUS WILL MAKE APPROPRIATE DOWNWARD ADJUSTMENTS...TEMPS NEAR OR SLIGHTLY BELOW NORMAL DURING THIS TIME. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... AS OF 645 AM FRIDAY... GRADUALLY DIMINISHING CONDITIONS WILL CONTINUE TO OCCUR IN CENTRAL NORTH CAROLINA DURING THE 12Z VALID TAF PERIOD. NUMEROUS AREAS OF RAIN WERE MOVING INTO THE WESTERN PIEDMONT WITH THE RAIN MORE SCATTERED IN MOST AREAS ALONG AND EAST OF U.S. 1. AS RAIN OCCURS...ANTICIPATE CEILINGS LOWERING TO MVFR...THEN AS MOISTURE CONTINUES TO INCREASE ALL MODELS SUPPORT CEILINGS FALLING TO IFR OR LIFR. RAIN WILL OCCUR LATEST TOWARD KRWI...AND ANTICIPATE AREAS OF LIGHT RAIN AND/OR DRIZZLE CONTINUING FROM LATE TODAY THROUGH THE EVENING. GFS MODEL SOUNDINGS STILL SHOW WINDS VEERING ALOFT AND INCREASING IN SPEED...STILL SUGGESTING WIND SPEEDS GRADUALLY INCREASING THROUGH AND ABOVE 2000FT. BETWEEN 09Z AND 12Z THERE IS A MARGINAL LLWS SIGNAL COINCIDENT WITH AN EXPECTED SURFACE WIND INCREASE...SO AGAIN HAVE KEPT LLWS OUT OF THE TAFS FOR THE 12Z ISSUANCE. REGARDLESS...AVIATION INTERESTS SHOULD BE PREPARED FOR VEERING WINDS WITH HEIGHT AS THEY INCREASE...WITH VALUES AT LEAST TO 35KT AT AND JUST ABOVE 2000FT LATE TONIGHT. BEYOND THE 12Z VALID TAF PERIOD...ALONG WITH SOME CONCERNS FOR LLWS...WIDESPREAD SUB-VFR CONDITIONS...MANY AREAS IFR OR LIFR...CONTINUE INTO SATURDAY...AHEAD OF A STRONG COLD FRONT THAT SWEEPS ACROSS CENTRAL NORTH CAROLINA. WHILE AN ISOLATED THUNDERSTORM COULD OCCUR SATURDAY IN CENTRAL NORTH CAROLINA...A BAND OF SHOWERS PRODUCING GUSTY WESTERLY WINDS MOVING ACROSS CENTRAL NORTH CAROLINA DURING THE AFTERNOON AND VERY EARLY EVENING COULD CERTAINLY POSE AN AVIATION CONCERN. AVIATION INTERESTS OPERATING SATURDAY SHOULD MONITOR THE LATEST CONVECTIVE AVIATION INFORMATION AND THE TIMING OF ANY SUCH BAND. CONDITIONS RAPIDLY BECOME VFR SATURDAY NIGHT CONTINUING INTO MONDAY. A PERIOD OR TWO OF MVFR CONDITIONS IS POSSIBLE IN LIGHT PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...DJF SHORT TERM...DJF LONG TERM...NP AVIATION...DJF
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
549 AM EST FRI JAN 10 2014 .SYNOPSIS... UPPER TROUGH EXITS EAST BY NOON. TEMPERATURES MODERATING INTO SATURDAY BEFORE COLD FRONT WITH RAIN CROSSES. WEAK HIGH PRESSURE PASSES SUNDAY. COLD FRONTS DUE EARLY AND LATE NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... RADAR IMAGES SHOW A BROAD AREA OF LIGHT PCPN BOUNCING FROM LIGHT RAIN TO MIXED SNOW MAINLY NORTHERN PORTIONS OF SOUTHEAST OH AND NORTHERN EXTREME OF WV. EXPECT THIS AREA TO GRADUALLY MOVE EASTWARD THROUGH THE EARLY MORNING HOURS. PCPN SHOULD BE PUSHED EAST OVER THE EASTERN MOUNTAINS BY MID MORNING LEAVING THE LOWLANDS PCPN FREE...AND DIMINISHING OVER THE MOUNTAINS TOWARDS NOON. THE HIGH RESOLUTION MODEL HRRR HAS THE CLOSER SOLUTION WHEN COMPARED WITH RADAR IMAGES. THE RUC13 LOOKS ABOUT 6 TO 12 HOURS SLOWER THAN ACTUAL WEATHER MOVING THROUGH. ADJUSTED POPS PER LATEST RADAR IMAGES AND THE MATCHING HRRR MODELS THROUGH FRIDAY MORNING. TEMPERATURES ACROSS THE LOWLANDS SLOWLY INCREASING MAKING TRANSITIONING PCPN INTO ALL RAIN. WARM AIR ADVECTION WILL CONTINUE UNDER SOUTHWEST FLOW KEEPING PCPN LIQUID AND BRINGING RELATIVELY WARMER TEMPERATURES COMPARED WITH PREVIOUS DAYS. BELIEVE ONCE RAIN SHOWERS MOVE EAST BY NOON...IT WILL BE A RELATIVELY DRY FRIDAY. HOWEVER...A STRONG COLD FRONT APPROACHES FROM THE WEST LATE TONIGHT...WITH A GOOD CHANCE FOR PCPN AND SOME GUSTY WIND. NOT EXITED ABOUT MODELS SHOWING H85 FLOW ABOUT 50 KNOTS LATER TONIGHT INTO EARLY SATURDAY MORNING. SOUTHWEST FLOW PARALLEL TO THE MOUNTAIN...UPGLIDE NOTICEABLE IN 280K ISENTROPIC CHARTS...AND THE POSSIBILITY OF NIGHT TIME DECOUPLING WILL MAKE THIS STRONG FLOW TO STRUGGLE TO MIX DOWN TO THE SFC TONIGHT. INCREASED ONSET OF PCPN TO CATEGORICAL LATE TONIGHT SPREADING FROM WEST TO EAST. WENT WITH THE MOST REASONABLE MOS CONSENSUS FOR TEMPERATURES THROUGH THE PERIOD. TEMPERATURES OVER THE EASTERN SLOPES COULD REMAIN AT OR BELOW FREEZING ON PROTECTED VALLEYS. THEREFORE...KEPT THE WINTER WEATHER ADVISORY FOR FREEZING RAIN FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 8 AM THIS MORNING. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... PACIFIC COLD FRONT STILL ON TRACK TO SWEEP ACROSS THE FORECAST AREA FROM WEST TO EAST SATURDAY MORNING...WITH ASSOC UPPER TROUGH PROGRESSING NORTHEASTWARD ACROSS THE GREAT LAKES REGION DURING THE DAY ON SATURDAY. STRONG LOW LEVEL WINDS PUSH INTO MAINLY THE WESTERN PARTS OF THE AREA OVERNIGHT FRI NIGHT...WHICH CONTINUE INTO THE SHORT TERM PERIOD EARLY SATURDAY MORNING. 850MB WINDS ARE PROGGED AROUND 70-75KTS ACROSS THE WESTERN ZONES AND NEAR 50KTS AT 925MB. WIND SPEEDS THIS STRONG AT THIS ALTITUDE WITH ASSOC PRECIP ALWAYS BRING SOME CONCERN...AS IT/S TOUGH TO KNOW JUST HOW MUCH PRECIP DRAG WILL BE ABLE TO BRING STRONG WINDS TO THE SURFACE. HOWEVER...WITH A STOUT INVERSION BELOW 900MB AND A TURNING OF WIND DIRECTION IN LOW-LEVELS SHOULD RESULT IN LESS RISK FOR HIGH WINDS AT THE SURFACE VERSUS PREVIOUS EVENTS THIS FALL/WINTER. SPC HAS NOT INCLUDED OUR FORECAST AREA IN A GENERAL RISK. NONETHELESS..SOMETHING TO WATCH EARLY SATURDAY MORNING AS THE PRECIP MOVES ACROSS. ALL IN ALL THOUGH...NOT MUCH CHANGE WITH PREV FORECAST THINKING. CATEGORICAL POPS EVERYWHERE DURING THE MORNING HOURS SATURDAY WITH THE FRONT. HIGH PWATS AROUND AN INCH SHOULD SPELL A FAIRLY QUICK QUARTER TO HALF INCH OF RAIN FOR MOST LOCATIONS...PERHAPS A LITTLE MORE IN THE EASTERN MOUNTAINS. NO HYDRO CONCERNS ARE EXPECTED WITH THIS SYSTEM HOWEVER. CONTINUED PREV FORECAST THINKING WITH REGARD TO A SLIGHT NON-DIURNAL TREND IN TEMPS ON SATURDAY WITH THE WARMEST 850MB/925MB TEMPS OCCURRING OVER WESTERN/CENTRAL AREAS BTWN 15Z-18Z SAT. THE BULK OF THE PRECIP SHOULD BE ALONG AND EAST OF THE I79 CORRIDOR BY 18Z SAT...WITH SYNOPTIC PRECIP WINDING DOWN AREA-WIDE BY 00Z SUN. WILL KEEP INHERITED HIGH CHANCE POPS HOWEVER ALONG THE EASTERN SLOPES A LITTLE LONGER WITH A WESTERLY UPSLOPE FLOW CONTINUING. STILL APPEARS THE STRONGEST WINDS COME LATE SAT AFTERNOON INTO THE EARLY OVERNIGHT HOURS SAT NIGHT POST-FRONT...WITH GUSTS IN THE HIGH COUNTRY TOPPING 40KTS. BY SATURDAY NIGHT ALL LOCATIONS EXCEPT THE EASTERN MOUNTAINS SHOULD BE PRECIP-FREE. HIGHER ELEVATIONS MAY SEE SOME LINGERING LIGHT RAIN OR SNOW SHOWERS THROUGH AROUND THE 06Z-09Z SUN TIME FRAME WITH DEPTH OF LLVL MOISTURE DECREASING...BUT AGAIN...AMOUNTS ARE EXPECTED TO BE VERY LIGHT WITH MOST AREAS PROBABLY ACTUALLY ONLY EXPERIENCING DRIZZLE OR FLURRIES. OVERNIGHT MINS BY EARLY SUN STILL EXPECTED TO BE IN THE LOW/MID 30S MOST LOWLAND LOCATIONS...WITH MID/UPPER 20S FOR THE MOUNTAINS. INITIALLY CLOUDY SKIES DURING THE EARLY OVERNIGHT HOURS SHOULD GRADUALLY BECOME MOSTLY CLEAR TO PARTLY CLOUDY FOR THE LOWLANDS BY DAWN SUNDAY...WITH OF COURSE LINGERING CLOUDS IN THE MOUNTAINS. SUNDAY AND SUNDAY NIGHT...SFC HIGH PRESSURE PASSES TO OUR SOUTH WITH WINDS BACKING FROM THE WEST TO THE SOUTH BY SUNDAY NIGHT. FLOW ALOFT ALSO BACKS FROM NEAR ZONAL TO SOUTHWESTERLY AS THE NEXT UPPER TROUGH DIGS QUICKLY SOUTHEAST INTO THE CENTRAL CONUS. STILL...A NICE PERIOD WITH MOSTLY SUNNY SKIES FOR ALL LOCATIONS IS EXPECTED. CONTINUED TO NUDGE MAX TEMPS UPWARD FOR SUNDAY...AS WAS THE PREVIOUS FORECAST TREND. 850MB/925MB TEMPS SUGGEST LOWLAND LOCATIONS NEAR THE CRW-HTS CORRIDOR APPROACHING 50F DEGREES. WILL RAISE TEMPS GENERALLY TO THE MID/UPPER 40S LOWLANDS...WITH MID 30S ON HIGHEST PEAKS. OVERNIGHT MINS SUNDAY NIGHT/MONDAY MORNING FOR THE LOWLANDS IN THE LOW/MID 30S STILL LOOK ON TRACK. DID RAISE EASTERN MOUNTAIN MINS UP AND ALSO CODED UP A NON-DIURNAL TEMP CURVE HERE...WITH DECENT 850MB WARM ADVECTION NOTED ON CONSENSUS OF MODEL OUTPUT IT APPEARS THAT THE MIN TEMP WILL BE REALIZED CLOSE TO MIDNIGHT FOR LOCATIONS SUCH AS SNOW WITH TEMPS CONTINUING A SLOW RISE TOWARDS DAWN MONDAY. && .LONG TERM /MONDAY THROUGH THURSDAY/... HIGH PRESSURE OF THE SE US WILL BRING A DRY START TO THE LONG TERM PERIOD. THERE IS POOR AGREEMENT BETWEEN THE ECMWF AND GFS ON SYSTEM ARRIVING LATE MONDAY. BOTH INDICATE A FRONTAL PASSAGE...BUT THE ECMWF ALSO SHOWS A SURFACE WAVE RIDING THE FRONT OUT OF THE SE...NORTHEAST JUST EAST OF THE APPALACHIANS. THE GFS DOES NOT HAVE THIS...AND IS INSTEAD JUST A COLD FRONTAL PASSAGE CONNECTED TO A SURFACE LOW NORTH OF THE GREAT LAKES. TRENDED TOWARD THE ECMWF...WHICH MESHES WELL WITH LATEST WPC GUIDANCE TOO. HAVE CHANCE POPS ACROSS WV ZONES WITH THE FRONT/SURFACE WAVE...SLIDE THOSE OUT TUESDAY. 500MB SHORTWAVE TROUGH PASSES WITH THE FRONT...WITH LARGER SCALE TROUGH ARRIVING MIDWEEK...BRINGING AN INCREASE IN POPS AGAIN TUESDAY NIGHT INTO WEDNESDAY. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... LATEST RADAR IMAGES INDICATE AN AREA OF SHOWERS MOVING OVER THE EASTERN MOUNTAINS THIS MORNING. EXPECT RAIN SHOWERS TO EXIT THE EASTERN MOUNTAINS BY MID MORNING. HOWEVER...AREAS UNDER TEMPERATURES AT OR BELOW FREEZING IN POCAHONTAS AND RANDOLPH COUNTIES COULD EXPERIENCE BRIEF PERIODS OF FREEZING RAIN. SOUTHWEST FLOW BRINGS WARM AIR ADVECTION...WHILE COLD AIR MASS REMAINS IN PLACE FAR NORTH OVER PORTIONS OF SOUTHEAST OH AND EXTREME NORTHERN WV. ALL PCPN SHOULD BE ALL RAIN FROM NOW ON ACROSS THE LOWLANDS AND CENTRAL MOUNTAINS. BRIEF PERIODS OF IFR/MVFR CEILINGS EXPECTED AT BKW AFTER 09Z...AND ACROSS ALL SITES FRIDAY AFTERNOON AROUND 17Z. OTHERWISE...VFR/MVFR MIST AND RAIN EXPECTED FOR THE MOST PART ON FRIDAY. PCPN SHOULD START DIMINISHING FROM WEST TO EAST FROM 13Z TO 17 FRIDAY. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY... ALTERNATE SCENARIOS: TIMING AND ONSET OF PRECIP MAY VARY. PRECIP TYPE AND CIG CATEGORY MAY VARY FROM FORECAST. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY M H H H H H H H H H H H BKW CONSISTENCY H H H M M M M M M M M M EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 12Z SATURDAY... IFR CONDITIONS IN RAIN COULD DEVELOP SATURDAY INTO SUNDAY IN STRONG FLOW ALOFT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...FREEZING RAIN ADVISORY UNTIL 8 AM EST THIS MORNING FOR WVZ046- 047. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/50 NEAR TERM...ARJ SHORT TERM...50 LONG TERM...MZ AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
504 AM CST FRI JAN 10 2014 .UPDATE...THIS MORNING ISSUED AT 504 AM CST FRI JAN 10 2014 WITH VISIBILTIIES DETERIORATING RAPIDLY ACROSS THE AREA...DECIDED TO GO WITH A DENSE FOG ADVISORY FOR MUCH OF THE FORECAST AREA. THE LONE EXCEPTIONS ARE CLARK AND TAYLOR COUNTIES IN CENTRAL AND NORTH CENTRAL WISCONSIN. WHILE THE VISIBILITIES ARE STILL MVFR NORTH OF INTERSTATE 90...EXPECT THESE TO RAPIDLY DETERIORATE AS TEMPERATURES CONTINUE TO CLIMB ABOVE THE GROUND TEMPERATURE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 402 AM CST FRI JAN 10 2014 AT 4 AM...A SHORT WAVE TROUGH WAS LOCATED OVER THE DAKOTAS. SOUTHERLY WINDS AND WARM AIR ADVECTION AHEAD OF THIS SYSTEM HAVE CAUSED THE TEMPERATURES TO SLOWLY RISE OVERNIGHT. VISIBILITIES HAVE DROPPED TO LESS THAN A MILE ACROSS MUCH OF NORTHEAST IOWA AND SOUTHEAST MINNESOTA. WE HAVE STARTED TO HEAR OF A FEW ACCIDENTS DUE TO THE SLICK ROADS. WHILE SOME OF THIS MOISTURE IS BEING DEPOSITED BY THE FOG AND THE REMAINDER OF IT IS BEING CAUSED BY THE DEW POINT TEMPERATURES CLIMBING ABOVE THE GROUND TEMPERATURE. WITH TEMPERATURES BELOW FREEZING THIS MOISTURE IS FREEZING. STILL DEBATING ON WHETHER TO ISSUE A FREEZING FOG ADVISORY OR A SPECIAL WEATHER STATEMENT. LIKE THE 09.18Z MODELS...WITH BOTH THE 270 AND 280K SHOWING VERY LITTLE LIFT THIS MORNING AND THE BUFKIT SOUNDINGS SHOWING SUBSIDENCE CO-LOCATED WITH THE LOW LEVEL MOISTURE...NOT EXPECTING MUCH PRECIPITATION THIS MORNING. DUE TO THIS...DRAMATICALLY LOWERED THE PRECIPITATION CHANCES FOR THIS MORNING. IF THERE IS ANY PRECIPITATION IT WILL BE IN THE FORM OF DRIZZLE OR FREEZING DRIZZLE. THIS PART OF THE FORECAST IS VERY TRICKY BECAUSE IT WILL BE HIGHLY DEPENDENT UPON HOW MUCH ARE THE ROADS ABLE TO WARM. DESPITE THE CLOUDS...THE SUN/S INFRARED RADIATION WILL CAUSE THE ROADS TO WARM UP. OVER THE PAST COUPLE OF DAYS...THE ROADS HAVE WARMED INTO THE MID AND UPPER 20S DURING THE AFTERNOON. THIS IS DESPITE THE VERY COLD AIR TEMPERATURES. WITH TEMPERATURES MUCH WARMER TODAY /LOWER TO MID 30S/...EXPECT THE UNSHELTERED ROADS TO WARM VERY CLOSE TO THE AIR TEMPERATURE. FOR THIS AFTERNOON AND EVENING...THE 10.00Z HAVE SHIFTED SOUTH WITH ITS 500 MB VORTICITY MAXIMUM. AS A RESULT...THE TRACK OF THE LOW PRESSURE SYSTEM AND ITS PRECIPITATION SHIFTED FURTHER TO THE SOUTHEAST. DESPITE THE WARM LAYER ALOFT COOLING ALOFT...THERE HAS ALSO BEEN A LOSS ICE ALOFT IN THE BUFKIT SOUNDINGS. THE -10C SURFACE SHOWS THAT THE RELATIVE HUMIDITIES FROM CHARLES CITY IOWA TO WAUSAU ARE AS LOW AS 70 PERCENT. AS A RESULT...EXPECT A BIT MORE LIQUID THAN SNOW WITH THIS SYSTEM. THIS MORE PROBLEMATIC LATE THIS AFTERNOON AND EVENING...BECAUSE WE WILL BE LOSING THE LONG RADIATION FROM THE SUN AND THIS WILL CAUSE THE MANY OF THE ROADS TO FALL QUICKLY BELOW FREEZING. DUE TO THE MIX PRECIPITATION AND A FURTHER SOUTHEAST SHIFT IN THE PRECIPITATION...LOWERED THE SNOW AMOUNTS INTO THE 1 TO 3 INCH RANGE. ICING WILL BE GENERALLY LESS THAN 5 HUNDREDTHS OF AN INCH. DUE TO THIS ICING...KEPT THE WINTER WEATHER ADVISORY GOING. FOR LATE TONIGHT...THE PRECIPITATION WILL BEGIN TO SHIFT EAST OF THE AREA. AS THIS OCCURS...BOTH THE BUFKIT SOUNDINGS AND -10C SURFACE SHOW THAT ICE WILL BE RETURNING TO THE AREA. AS A RESULT...EXPECT THAT PRECIPITATION WILL CHANGE OVER LIGHT SNOW BEFORE IT ENDS. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 402 AM CST FRI JAN 10 2014 ON SATURDAY...A DEFORMATION BAND WILL PRODUCE SOME LIGHT SNOW MAINLY EAST OF THE MISSISSIPPI RIVER DURING THE MORNING. LITTLE... IF ANY...ACCUMULATION IS EXPECTED. ON SATURDAY NIGHT AND SUNDAY MORNING...A WARM FRONT WILL MOVE THROUGH THE REGION. 850 MB TEMPERATURES QUICKLY WARM TO AROUND 7C. SOUTHERLY WINDS IN THE WARM SECTOR OF THIS SYSTEM WILL ALLOW TEMPERATURES TO WARM INTO THE MID AND UPPER 30S. WHILE THE GEM GENERATES SOME PRECIPITATION AHEAD OF THIS FRONT...THE REMAINDER OF THE MODELS KEEP THE AREA DRY. AS A RESULT...WENT WITH A DRY FORECAST FOR THE AREA. ON SUNDAY NIGHT...A COLD FRONT MOVES THROUGH THE REGION. MUCH OF THE FORCING ASSOCIATED WITH THIS SYSTEM WILL REMAIN WELL NORTH OF THE FORECAST AREA. HOWEVER THERE APPEARS TO BE ENOUGH FRONTOGENESIS ALONG THIS FRONT TO PROVIDE ENOUGH LIFT TO WARRANT A SLIGHT CHANCE OF RAIN AND SNOW. ON MONDAY NIGHT AND TUESDAY...BOTH THE GFS AND ECMWF ARE SHOWING THAT A STRENGTHENING SHORT WAVE TROUGH WILL MOVE THROUGH NORTHEAST IOWA AND SOUTHERN WISCONSIN. WITH THIS BEING A NEW FEATURE IN THE MODELS...OPTED TO JUST ADD A SMALL CHANCE OF SNOW WITH IT. ON TUESDAY AND TUESDAY NIGHT...THE MODELS ARE NOW SHOWING STRONG COLD AIR ADVECTION DEVELOPING IN THE WAKE OF THE SHORT WAVE TROUGH. THIS DROPS THE 850 MB TEMPERATURES DOWN TO -10C. IF THIS VERIFIES...HIGH TEMPERATURES WILL REMAIN IN THE TEENS. SINCE THIS IS A NEW FEATURE...LOWERED THE TEMPERATURES BY 2 TO 3 DEGREES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1100 PM CST THU JAN 9 2014 IFR/MVFR CLOUDS HELD FAST ACROSS THE TAF SITES...AND WILL PERSIST THROUGH FRI NIGHT. EXPECTING SOME ADDITIONAL LOWERING ON FRI AS THE LOW SATURATION INCREASES AHEAD OF AN APPROACHING LOW. COULD BE SOME FZDZ EARLY FRI AFTERNOON WHEN CLOUD DEPTH AND SUFFICIENT LIFT COME TOGETHER. GRADUALLY...CLOUD DEPTH WILL DEEPEN ENOUGH FOR ICE IN THE CLOUD...AND SNOW. THIS LOOKS TO BE NEAR 00Z AT KRST/KLSE. EXPECTING SNOW ACCUMULATIONS OF 2 TO 4 INCHES...MOST OF WHICH WILL FALL FRI NIGHT. THINK THE THREAT FOR FZRA/PL IS LIMITED AT THIS TIME...BETTER CHANCES SOUTH/SOUTHEAST. WINDS WILL STAY SOUTHERLY THROUGH MUCH OF FRIDAY...BECOMING WEST/NORTHWEST AS THE LOW TRACKS INTO SOUTHERN WI FRI EVENING. INTERESTING NOTE FOR THIS EVENING...VERY FINE -SN HAS FALLEN FOR A FEW HOURS AT KRST. LATEST RAP SOUNDINGS INDICATE NEAR SFC TEMPS ARE NEAR -10 C...WHICH WOULD BE ENOUGH TO PRODUCE ICE CRYSTALS...AND IS THE LIKELY CAUSE FOR THE VERY LIGHT PCPN. IT WILL CONTRIBUTE TO VSBY REDUCTIONS...AND COULD MAKE RUNWAYS SLICK. CURRENT EXPECTATION IS THAT IT COULD LAST INTO THE OVERNIGHT HOURS...BUT SHOULD BE DONE BEFORE 12Z. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR WIZ032>034-041>044- 053>055-061. WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR WIZ017-029-034-041>044-053>055-061. MN...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR MNZ079-086>088- 094>096. WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR MNZ096. IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR IAZ008>011-018-019- 029-030. WINTER WEATHER ADVISORY FROM NOON TODAY TO 6 AM CST SATURDAY FOR IAZ010-011-029-030. && $$ UPDATE...BOYNE SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS ALBANY NY
447 PM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO SHIFT EASTWARD AND OFFSHORE OVERNIGHT...AS A STRENGTHENING STORM SYSTEM MOVES ACROSS THE WESTERN GREAT LAKES AND SOUTHEAST CANADA LATE TONIGHT INTO SATURDAY. MILDER AIR WILL BE USHERED INTO THE REGION AS THE SYSTEM AND ITS ASSOCIATED FRONTAL SYSTEM APPROACHES. SOME FREEZING RAIN IS POSSIBLE LATE TONIGHT INTO EARLY SATURDAY MORNING...THEN RAIN IS EXPECTED INTO SATURDAY NIGHT...WITH SOME LOCALLY HEAVY RAIN POSSIBLE DURING THE AFTERNOON AND EVENING HOURS. IMPROVING CONDITIONS...ALONG WITH ABOVE NORMAL TEMPERATURES ARE EXPECTED FOR SUNDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... ...FREEZING RAIN ADVISORIES ISSUED FOR THE OVERNIGHT HOURS... ...FLOOD WATCH REMAIN IN EFFECT FOR SAT AFTN THROUGH SUN AFTN... AS OF 445 PM EST...SOME BREAKS IN THE CLOUDS CONTINUE ACROSS PORTIONS OF THE GREATER CAPITAL REGION...WITH MOSTLY CLOUDY SKIES ELSEWHERE. TEMPS HAVE RISEN INTO THE LOWER 30S FOR MOST AREAS SOUTH AND EAST OF THE CAPITAL REGION...WITH MAINLY UPPER 20S TO LOWER 30S TO THE NORTH AND WEST. THE AFOREMENTIONED PARTIAL CLEARING APPEARS TO HAVE BEEN LARGELY DUE TO SOME SUBSIDENCE IN THE WAKE OF THE SHORTWAVE...WHICH PASSED EAST ACROSS THE REGION EARLIER TODAY...AND ALSO DUE TO SOME DOWNSLOPING OFF THE CATSKILLS DUE TO A STRENGTHENING SOUTHWEST FLOW AROUND 4000-6000 FT AGL. LOOKING TO OUR SOUTH...PRECIPITATION CONTINUES TO DEVELOP ACROSS PORTIONS OF THE MID ATLANTIC STATES...WHERE LOW/MID LEVEL ISENTROPIC LIFT AND THETA-E ADVECTION INCREASES. SHORT-TERM MODELS...SUCH AS THE RAP13 AND HRRR SUGGEST THAT THIS AREA OF FORCING TRANSLATES NORTH NORTHEAST INTO SOUTHERN PORTIONS OF THE REGION BETWEEN 10 PM AND MIDNIGHT...AND GENERALLY BETWEEN MIDNIGHT AND 4 AM FURTHER N AND W. THERMAL PROFILES SUGGEST HYDROMETEORS SHOULD BE PRIMARILY LIQUID...ALTHOUGH SOME SLEET COULD BE MIXED IN ACROSS NORTHERN AREAS INITIALLY. SFC TEMPS...WHICH ARE CURRENTLY JUST BARELY ABOVE FREEZING...ARE EXPECTED TO FALL AT LEAST A FEW DEGREES THIS EVENING...BEFORE LEVELING OFF...AND EVENTUALLY RISING AFTER MIDNIGHT. HOWEVER...IT APPEARS THAT SOME LIGHT PRECIPITATION WILL DEVELOP BEFORE SFC TEMPS RISE ABOVE FREEZING. IN ADDITION...EVEN IF SFC TEMPS ARE AROUND OR A BIT ABOVE FREEZING...THE GROUND REMAINS VERY COLD FROM THE RECENT COLD SPELL...SO UNTREATED SURFACES MAY ACCRETE A LIGHT GLAZE OF ICE...EVEN WITH TEMPS SLIGHTLY ABOVE FREEZING. THEREFORE...A FREEZING RAIN ADVISORY HAS BEEN ISSUED AREAWIDE...ALTHOUGH THE ENDING TIMES OF THE ADVISORY ARE EARLIER ACROSS SOUTHERN AREAS...AND LATER...MID MORNING...FOR NORTHERN AREAS...WHERE SUBFREEZING SFC TEMPS MAY LINGER IN SHELTERED VALLEY AREAS. TOTAL ICE ACCRETION IS NOT EXPECTED TO BE MUCH...GENERALLY UNDER ONE TENTH OF AN INCH...BUT MAY STILL HAVE HIGH IMPACTS ON TRAVEL DUE TO THE FROZEN GROUND. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/... SATURDAY...AS MENTIONED...SOME NORTHERN AREAS...PARTICULARLY ACROSS PORTIONS OF THE LAKE GEORGE REGION...AND SOUTHWEST ADIRONDACKS...AND POSSIBLY SOUTHEAST VT MAY REMAIN NEAR THE FREEZING MARK THROUGH 9 AM EST SAT AM...WHERE POCKETS OF FREEZING RAIN MAY LINGER. OTHERWISE...EXPECT PERIODS OF RAIN OR DRIZZLE THROUGH MUCH OF THE DAY. AREAS OF FOG...SOME LOCALLY QUITE DENSE...WILL ALSO LIKELY OCCUR AS THE INCREASINGLY MILD AND MOIST AIR DRIFTS ACROSS THE VERY COLD GROUND. IT ALSO MAY BECOME QUITE BREEZY/WINDY ACROSS HIGHER ELEVATIONS OF THE SOUTHERN GREEN MTNS/BERKSHIRES AND TACONICS...WHERE SOUTH TO SOUTHEAST WINDS MAY GUST UP TO 35-45 MPH AT TIMES. IN VALLEY AREAS...NOT EXPECTING AS MUCH WIND DUE TO A RATHER STRONG LOW LEVEL INVERSION...BUT SHOULD THE LOW LEVEL INVERSION BE WEAKER THAN CURRENTLY FORECAST...SOME STRONGER WINDS COULD MIX WITHIN NORTH/SOUTH ORIENTED VALLEYS. THEN...AS THE COLD FRONT APPROACHES FROM THE WEST LATER IN THE DAY...A BAND OF MODERATE TO LOCALLY HEAVY RAINFALL IS EXPECTED TO DEVELOP AND MOVE FROM W TO E. THIS BAND OF RAIN COULD EVOLVE INTO A NARROW COLD FRONTAL RAINBAND...AND PRODUCE LOCALLY VERY HEAVY RAINFALL...AND STRONG WIND GUSTS...AND RADAR TRENDS WILL HAVE TO BE MONITORED. SAT NT...THE AFOREMENTIONED FRONTAL RAINBAND SHOULD CONTINUE MOVING EAST ACROSS THE REGION IN THE EVENING. BEHIND IT...A BRIEF PERIOD OF LINGERING SHOWERS OR RAIN IS POSSIBLE...BEFORE THE RAIN ENDS FROM W TO E IN MOST AREAS BY MIDNIGHT. HOWEVER...SOME SHOWERS OF RAIN...AND EVENTUALLY SNOW SHOULD DEVELOP ACROSS PORTIONS OF THE SOUTHERN ADIRONDACKS LATER AT NIGHT WITH MINOR ACCUMS. WEST WINDS WILL ALSO INCREASE LATER AT NIGHT...ESP WITHIN THE MOHAWK RIVER VALLEY/CAPITAL REGION/BERKSHIRES. SUNDAY...A BRISK WEST WIND SHOULD CONTINUE THROUGH EARLY AFTERNOON...WITH SOME GUSTS OF 30-40 MPH POSSIBLE...ESP DOWN THE MOHAWK VALLEY AND INTO THE CAPITAL REGION AND BERKSHIRES. HOWEVER...DESPITE GUSTY WINDS...TEMPS WILL ACTUALLY BE ABOVE NORMAL GIVEN THE PACIFIC ORIGINS OF THE INCOMING AIRMASS. SOME SHOWERS OF RAIN/SNOW WILL BE POSSIBLE ACROSS NORTHERN AREAS...ESP EARLY...ALONG WITH PARTLY TO MOSTLY CLOUDY SKIES. HOWEVER...SKIES SHOULD CLEAR FROM SOUTH TO NORTH IN THE AFTERNOON. EXPECT TEMPS TO REACH THE LOWER/MID 40S IN VALLEYS...AND MID 30S TO AROUND 40 ACROSS HIGHER ELEVATIONS. SUN NT-MON...GENERALLY FAIR...WITH ABOVE NORMAL TEMPS. EXPECT MINS TO FALL INTO THE 20S...AND MON MAXES REACHING THE LOWER/MID 40S IN MOST AREAS. SOME CLOUDS WILL INCREASE LATE MONDAY IN ADVANCE OF THE NEXT SYSTEM. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE LONG TERM PERIOD WILL BE CHARACTERIZED BY SLIGHTLY ABOVE NORMAL TEMPERATURES AND QUICK MOVING STORM SYSTEMS BRINGING CHANCES FOR RAIN/SNOW SHOWERS. AT THE START OF THE LONG TERM PERIOD...A LARGE AMPLITUDE UPPER-LEVEL PATTERN WILL BE IN PLACE ACROSS MUCH OF THE CONUS...WITH A LONGWAVE TROUGH ACROSS THE CENTRAL CONUS AND MEAN RIDGING/SOUTHWEST FLOW ACROSS THE EASTERN THIRD OF THE NATION. AT THE SURFACE...AN AREA OF LOW PRESSURE WILL BE TAKING SHAPE ACROSS THE LOWER MISSISSIPPI RIVER VALLEY. THERE CONTINUES TO BE SIGNIFICANT UNCERTAINTY REGARDING THE EVOLUTION OF THIS SYSTEM...PARTICULARLY IN THE EVOLUTION OF A PAIR OF DISTURBANCES ASSOCIATED WITH THE NORTHERN AND SOUTHERN STREAMS. THE 12Z GFS...GGEM AND MOST GEFS MEMBERS CONTINUE TO FAVOR A MORE PROGRESSIVE SOLUTION...WITH THE NORTHERN STREAM DOMINATING AND ALLOWING A PROGRESSIVE TROUGH AND WEAK SURFACE LOW TO MOVE THROUGH THE REGION TUESDAY WITH CHANCES FOR RAIN/SNOW SHOWERS. MEANWHILE...THE 12Z ECMWF CONTINUES TO BE SLOWER FAVORING A SOUTHERN STREAM DOMINATED SURFACE LOW THAT QUICKLY RACES UP THE EASTERN SEABOARD AND THEN PHASES WITH THE NORTHERN STREAM...ALLOWING FOR A RATHER DEEP AND DYNAMIC SYSTEM TO PRODUCE WIDESPREAD PRECIPITATION ACROSS THE REGION. GIVEN LONG RANGE GUIDANCE DIFFICULTY IN HANDLING LARGE AMPLITUDE PATTERNS IN THE EXTENDED...HAVE GONE WITH CHANCE POPS FOR TUESDAY...SIDING CLOSE TO WPC GUIDANCE WHICH FAVORS A LOW PRESSURE SYSTEM TRACKING ACROSS THE REGION WITH RAIN/SNOW SHOWERS MONDAY NIGHT TRANSITIONING TO PRIMARILY RAIN DURING THE DAY TUESDAY. THIS SYSTEM QUICKLY EXITS TUESDAY NIGHT...LEAVING SCATTERED SNOW SHOWERS AND A BROAD UPPER-LEVEL TROUGH IN ITS WAKE. A SERIES OF DISTURBANCES WILL MOVE THROUGH THIS TROUGH LEADING TO ADDITIONAL CHANCES FOR RAIN/SNOW SHOWERS WEDNESDAY BEFORE TRANSITIONING TO ALL SNOW FOR WEDNESDAY NIGHT. BOTH THE 12Z GFS AND ECMWF HINT AT THE POTENTIAL FOR COASTAL LOW DEVELOPMENT WEDNESDAY NIGHT INTO THURSDAY...WHICH COULD ENHANCE SNOWFALL POTENTIAL ESPECIALLY EAST OF THE CAPITAL DISTRICT. WILL CONTINUE TO GO WITH CHANCE POPS THROUGHOUT THIS TIMEFRAME AS MODEL UNCERTAINTY REMAINS HIGH. WEAK HIGH PRESSURE WILL BUILD ACROSS THE REGION FOR THURSDAY...BRINGING DRY WEATHER AND CLEARING SKIES TO MUCH OF THE REGION BEFORE ANOTHER UPPER-LEVEL DISTURBANCE DIVING OUT OF THE GREAT LAKES REGION APPROACHES THE REGION TO END THE WORK WEEK. MODEL GUIDANCE CONTINUES TO INDICATE THAT THIS SYSTEM WILL HAVE LITTLE MOISTURE TO WORK WITH...HOWEVER IT WILL BRING A REINFORCING SHOT OF COLD AIR TO THE REGION FOR THE WEEKEND. HIGHS WILL INITIALLY RANGE FROM THE UPPER 30S TO UPPER 40S TUESDAY...BEFORE COOLING SLIGHTLY TO BETWEEN THE UPPER 20S AND MID 30S FOR THE REMAINDER OF THE WORK WEEK. LOWS WILL INITIALLY BE IN THE LOW TO MID 30S ACROSS THE REGION MONDAY AND TUESDAY NIGHT...BEFORE COOLING AND SETTLING INTO THE UPPER TEENS TO MID 20S FOR THE REMAINDER OF THE WORK WEEK. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... A RIDGE OF HIGH PRESSURE WILL CONTINUE TO MOVE EAST INTO THE NORTHERN ATLANTIC OCEAN. A COLD FRONT FROM THE OHIO VALLEY WILL CONTINUE TO MOVE EAST TOWARD OUR REGION. AHEAD OF THE APPROACHING COLD FRONT...A WEAK WARM FRONT WILL BRING THE CHANCE OF PRECIPITATION TO ALL THE TAF SITES. TEMPERATURES WILL SUPPORT A WINTRY MIX ESPECIALLY AT KPSF/KALB/KGFL FROM 03Z TO 09Z SATURDAY AT KALB/KPSF EXTENDING TO AS LATE AS 12Z SATURDAY AT KGFL. PRECIPITATION TYPE WILL CHANGE TO ALL RAIN AFTER 12Z SATURDAY AT ALL TAF SITES. THE MAIN COLD FRONT TO OUR WEST WILL NOT BE MOVING INTO THE REGION UNTO AFTER THE END OF THE TAF FORECAST PERIOD AFTER 18Z SATURDAY. WINDS WILL BE OUT OF THE SOUTHWEST TO START THE TAF PERIOD UP TO 00Z SATURDAY. WINDS WILL THEN SHIFT TO A SOUTH-SOUTHEASTERLY FLOW BEHIND THE WARM FRONT PASSAGE WITH WINDS BETWEEN 5-10 KTS. AT TIMES ALONG AND AHEAD OF THE FRONTAL PASSAGE...KGFL MAY EXPERIENCE SOME LLWS ESPECIALLY TOWARD THE END OF THE TAF PERIOD. VFR/MVFR CONDITIONS ARE EXPECTED UP TO 00Z SATURDAY WHICH WILL BE FOLLOWED BY MVFR CONDITIONS. AT TIMES...IFR CONDITIONS MAY BE PRESENT BETWEEN 06Z AND 12Z SATURDAY AS THE WARM FRONT WILL MAKE ITS WAY INTO THE REGION WITH WINTRY PRECIPITATION AND LOW VSBYS AND CEILINGS. OUTLOOK... SAT NT: HIGH OPERATIONAL IMPACT.BREEZY DEFINITE SHRA...RA...FG. SUN: MODERATE OPERATIONAL IMPACT. WINDY WITH GUSTS TO 34.0 SLIGHT CHANCE OF SHRA. SUN NT-MON: NO OPERATIONAL IMPACT. NO SIG WX. MON NT-WED: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN. && .HYDROLOGY... A FLOOD WATCH REMAINS IN EFFECT FOR SATURDAY AFTERNOON THROUGH SUNDAY...WITH THE PRIMARY THREAT ICE JAM FLOODING. A POWERFUL STORM SYSTEM WILL MOVE ACROSS THE REGION SATURDAY WITH VERY MILD AIR BEING USHERED IN AS THE SYSTEM APPROACHES WITH TEMPERATURES RISING INTO THE UPPER 40S TO LOWER 50S. THIS WILL LEAD TO SOME SNOW MELT. SOME MIXED WINTRY PRECIPITATION IS EXPECTED LATE TONIGHT INTO EARLY SATURDAY MORNING...THEN RAIN IS EXPECTED INTO SATURDAY NIGHT. THE RAIN MAY BE HEAVY AT TIMES DURING THE AFTERNOON AND EVENING HOURS. RAINFALL AMOUNTS OF ONE HALF OF AN INCH TO AN INCH ARE EXPECTED FROM THE CAPITAL DISTRICT NORTH AND WEST WITH 1 TO 2 INCHES TO THE SOUTH AND EAST. THE RAIN WILL FALL ON FROZEN GROUND WHICH WILL QUICKLY BECOME RUNOFF AND MAY CAUSE SOME STREET AND OR POOR DRAINAGE FLOODING OF LOW LYING AREAS. THE WARM TEMPERATURES...COMBINED WITH THE RAINFALL MAY CAUSE ICE MOVEMENT AND BREAK UP FOR ICE JAM FLOODING ON SOME RIVERS AND STREAMS. THE THREAT FOR ICE JAM FLOODING WILL BE GREATEST LATE SATURDAY AFTERNOON INTO SUNDAY. IT APPEARS THAT THE GREATEST POTENTIAL FOR FLOODING AT THIS TIME WILL INCLUDE...BUT NOT BE LIMITED TO...THE HOOSIC RIVER AT WILLIAMSTOWN AND EAGLE BRIDGE...AND THE WALLOOMSAC RIVER AT BENNINGTON. DESPITE THE PASSAGE OF THE SYSTEM...ABOVE NORMAL TEMPERATURES ARE EXPECTED TO PERSIST THROUGH EARLY NEXT WEEK. NIGHTTIME TEMPERATURES WILL FALL TO AROUND FREEZING OR BELOW. OUR NEXT BEST CHANCES FOR WIDESPREAD PRECIPITATION WILL TUESDAY. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR CTZ001-013. FREEZING RAIN ADVISORY FROM 10 PM THIS EVENING TO 4 AM EST SATURDAY FOR CTZ001-013. NY...FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR NYZ032-033-038>043-047>054-058>061-063>066-082>084. FREEZING RAIN ADVISORY FROM 10 PM THIS EVENING TO 4 AM EST SATURDAY FOR NYZ063>066. FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST SATURDAY FOR NYZ047>054-058>061. FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST SATURDAY FOR NYZ032-033-038>043-082>084. MA...FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR MAZ001-025. FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST SATURDAY FOR MAZ001-025. VT...FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY AFTERNOON FOR VTZ013>015. FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST SATURDAY FOR VTZ013>015. && $$ SYNOPSIS...IAA/KL NEAR TERM...KL SHORT TERM...KL LONG TERM...IRL AVIATION...LFM HYDROLOGY...KL/IAA/WASULA
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
318 PM EST FRI JAN 10 2014 .DISCUSSION... TONIGHT... EXPECT A SLIGHT CHANCE FOR SHOWERS TO LINGER INTO THE EARLY EVENING BUT OTHERWISE SKIES SHOULD BECOME PARTLY CLOUDY FOR A TIME. THE LOW LEVELS WILL REMAIN VERY MOIST AND EXPECT THAT LOW STRATUS WILL DEVELOP DURING THE LATE AFTERNOON AND OVERNIGHT. INCREASING WINDS JUST OFF THE SURFACE SHOULD INHIBIT FOG...BUT WILL CONTINUE OUR PREVIOUS FORECAST THAT MENTIONS PATCHY FOG. SOUTHERLY FLOW WILL KEEP MINIMUM TEMPS WELL ABOVE NORMAL... IN THE MID TO UPPER 60S. SAT... FRONTAL BOUNDARY IS PROGGED TO BE ENTERING THE WESTERN PANHANDLE EARLY AND PUSHING THROUGH THE BIG BEND REGION TOWARDS EARLY EVENING. THOUGH LOW LEVEL WINDS WILL BE INCREASING AS THE FRONT APPROACHES...THEY WILL BE VEERING TO THE SOUTHWEST...DECREASING CONVERGENCE. THE GFS ALSO SHOWS THAT THIS SOUTHWEST FLOW WILL TAP DRIER AIR THAT RESIDES OVER THE NORTHWEST CARIBBEAN. THE RESULT FROM THE MODEL IS VERY LOW PRECIP AMOUNTS. BASED ON QUITE HIGH DEW POINTS THOUGH...WILL RETAIN CHANCE POPS WITH VALUES AT 50 PERCENT IN THE NORTH AND 30 IN THE SOUTH. HAVE TRIMMED THUNDER CHANCES BACK TO NORTHERN SECTIONS...JUST AHEAD OF THE FRONT. THE WARM SOUTHWEST FLOW WILL BOOST MAX TEMPS INTO THE 80S. LATEST MOS HAS LOWER 80S NORTH AND MID 80S SOUTH. IF THE MORNING STRATUS BREAKS UP FAST ENOUGH AND PRE FRONTAL PRECIP HOLDS OFF LONG ENOUGH...A FEW SPOTS COULD APPROACH THEIR RECORD HIGHS. SAT NIGHT... A 130KT H30-H20 JET STREAK DIGGING ACRS THE NW CONUS WILL COMBINE WITH A 110KT JET LIFTING OUT OF THE RIO GRANDE VALLEY TO SHUNT THE NEXT SHORT WAVE FRONTAL TROF THROUGH CENTRAL FL. WHILE THE COMBO OF THESE TO UPR LVL FEATURES WILL PROVIDE SUFFICIENT ENERGY TO DRIVE THE FRONTAL BOUNDARY INTO S FL BY DAYBREAK...A STRONG MID LVL ANTICYCLONE OVER THE BAHAMA BANK/NW CARIB WILL DEFLECT THE MAJORITY OF THE SYSTEM ENERGY TO THE N. FURTHERMORE...MODEL SOUNDINGS ARE INDICATING A SIGNIFICANT AMOUNT OF DRY AIR THRU THE H85-H60 LYR WITH DEWPOINT DEPRESSIONS ON THE ORDER OF 10C IMMEDIATELY PRECEDING THE FROPA. THE FCST SOLUTION IS NOT UNREASONABLE...GIVEN THE FACT THAT THE LATEST RUC ANALYSIS SHOWS H85-H70 MEAN RH VALUES AS LOW AS 40PCT. FURTHERMORE...THE LIFTING NATURE OF THE LEADING JET STREAK TYPICALLY IS NOT CONDUCIVE TO SIGNIFICANT OUTBREAKS OF STRONG/SVR WX. FINALLY...DEEP LYR LAPSE RATES ACRS THE GOMEX/SW ATLC ARE RATHER WEAK...GENERALLY AOB 6C/KM. WILL KEEP POPS IN THE 30-40PCT RANGE... SHIFTING FOCUS FOR TSRA ACTIVITY FROM THE NRN CWA BTWN 00Z-06Z...AND THE SRN CWA TO 06Z-12Z TO COINCIDE WITH THE FROPA. TIMING OF THE FROPA WILL RESULT IN A FAIRLY WIDE MIN TEMP SPREAD. AREAS ALONG AND N OF I-4 WILL SEE MINS DROP INTO THE M/U50S DUE TO THEIR LONGER DURATION POST FRONTAL COOL AIR ADVECTION...WHILE AREAS ALONG THE TREASURE COAST WILL HOLD IN THE M/U60S AS THE CRUX OF THE COLD AIR WILL NOT HAVE MADE IT THAT FAR SOUTH BY DAYBREAK. SUN-SUN NIGHT... PROGRESSIVE WX PATTERN WILL PUSH THE POST FRONTAL HIGH PRES RIDGE ACRS THE GOMEX/DEEP SOUTH THRU THE DAY...THEN WELL INTO THE W ATLC BY DAYBREAK MON. MODERATE H100-H85 FLOW WILL RESPOND BY SHIFTING STEADILY FROM NW AT DAYBREAK...TO DUE N BY MIDDAY...TO THE E/NE BY SUNSET...THEN FINALLY TO THE SE OVERNIGHT. SHORT DURATION OF THE NRLY FLOW WILL LIMIT THE EFFECTS OF THE POST FRONTAL RIDGE TO THE SUN/SUN NIGHT TIME FRAME...GENERALLY RETURNING TEMPS TO NEAR CLIMO AVG FOR EARLY JAN. MAX TEMPS WILL BE IN THE U60S/L70S ALONG AND N OF I-4 AND L/M70S TREASURE COAST AND THE NE SHORE OF LAKE OKEECHOBEE. DVLPG ONSHORE FLOW WILL KEEP MIN TEMPS ALONG THE IMMEDIATE SPACE/TREASURE COASTS IN THE U50S/L60S...BUT ARE NOT EXPECTED TO BE STRONG ENOUGH TO KEEP INTERIOR TEMPS FROM DROPPING INTO THE U40S/L50 N OF I-4 AND INTO THE L/M50S TO THE S (AGAIN...NEAR CLIMO AVG). EXTENDED...(PREV DISC) SPLIT TROUGH MOVES THROUGH THE CENTRAL AND EASTERN US THROUGH THE EARLY PART OF THE WEEK WITH THE SOUTHERN BRANCH DRIVING CYCLOGENESIS SOMEWHERE BETWEEN THE SOUTHERN MISSISSIPPI VALLEY AND OHIO VALLEY... DEPENDING ON THE MODEL. THE ECMWF DEVELOPS A STRONGER AND MORE COHESIVE SYSTEM THAT LIFTS INTO THE MID-ATLANTIC ON TUESDAY...WHILE THE GFS KEEP A STRONG LOW OVER THE GREAT LAKES AND BROADER TROUGH/LOW PRESSURE ACROSS THE DEEP SOUTH. AS A RESULT...THE GFS IS QUICKER TO BRING A RETURN OF RAIN AND MOVE A FRONT THROUGH TUES NIGHT. ECMWF IS SIMILAR ON THE TIMING OF THE ACTUAL FRONT...BUT HOLDS OF ANY NOTABLE RAIN CHANCES UNTIL TUESDAY. HAVE BROADBRUSHED 20 POPS ON MONDAY TO TUESDAY TO ACCOUNT FOR THE DIFFERENCES. COOLER AND DRY WEATHER IS EXPECTED BEHIND THE FRONT DURING THE DAY ON WEDNESDAY. && .AVIATION...PRESENT CONDITIONS HAVE GONE VFR EVERYWHERE EXCEPT FOR LOCAL MVFR WHERE ISOLATED SHOWERS WERE OCCURRING ALONG THE TREASURE COAST. THE MAIN AVIATION CONCERN WILL AGAIN BE LATE NIGHT LOW STRATUS. SOUTHERLY LOW LEVEL WINDS LOOK STRONG ENOUGH TO INHIBIT DENSE FOG...BUT SOME LIFR CEILINGS COULD OCCUR ESPECIALLY ALONG AND WEST OF THE I-4 CORRIDOR. && .MARINE... TONIGHT...WEAKNESS IN PRESSURE GRADIENT WAS OVER THE WATERS BEHIND THE WEAKENING SURFACE TROUGH THAT HAS LIFTED TO THE NORTH. THIS WILL BE TEMPORARY THOUGH AS THE PRESSURE GRADIENT WILL START TO TIGHTEN BACK UP IN ADVANCE OF FRONTAL TROUGH THAT WILL BE REACHING NEAR THE FLORIDA PANHANDLE TOWARDS SUNRISE. WILL EXPIRE THE OFFSHORE ADVISORY WITH NEXT FORECAST ISSUANCE...THOUGH SEAS MAY ACTUALLY BE AROUND 7 FEET AT THAT TIME. WILL MENTION EXERCISE CAUTION FOR THE OFFSHORE LEGS THOUGH. SAT...SOUTH WINDS STARTING OUT THE DAY WILL SHIFT TO THE SOUTHWEST IN THE AFTERNOON. MARINE MOS INDICATES SPEEDS REACHING 20 KNOTS TOWARDS EVENING AT 41009. SINCE THIS IS A WARM ADVECTION PATTERN (OVER COOL CONTINENTAL SHELF WATERS) AND THERE WILL BE LIMITED FETCH WHEN THE SPEEDS INCREASE LATE...WILL HOLD OFF ON AN ADVISORY WITH THIS PACKAGE...BUT EXPECT ONE MAY BE NEEDED OFFSHORE SAT NIGHT. SAT NIGHT...POOR BOATING CONDITIONS AS A COLD FRONT PUSHES RAPIDLY ACRS THE LCL ATLC. MODERATE TO FRESH SW BREEZE AT SUNSET WILL VEER STEADILY TO THE W BY AROUND MIDNIGHT...THEN TO THE NW BY DAYBREAK. OFFSHORE COMPONENT WILL LIMIT SEA HEIGHTS TO 3-5FT NEARSHORE AND 4-6FT OFFSHORE...UP TO 7FT OVER THE GULF STREAM N OF SEBASTIAN INLET. SUN-SUN NIGHT...PROGRESSIVE WX PATTERN WILL PUSH THE POST FRONTAL HI PRES RIDGE INTO THE W ATLC THRU THE PD. SFC/BNDRY LYR WINDS WILL RESPOND BY VEERING AROUND THE CLOCK...MODERATE TO FRESH NW BREEZE AT DAYBREAK...DIMINISHING TO GENTLE TO MODERATE NRLY BREEZE BY MIDDAY...LIGHT TO GENTLE NE BREEZE BY SUNSET...VEERING TO E/SE OVERNIGHT. SHORT DURATION OF THE ENHANCED WIND FIELD WILL LIMIT SEA HEIGHTS TO 3-5FT NEARSHORE AND 5-7FT OFFSHORE AROUND DAYBREAK... DECREASING TO 2-4FT NEARSHORE AND 3-5FT OFFSHORE AROUND SUNSET... THEN 2-4FT AREAWIDE OVERNIGHT. MON-TUE...(PREV DISC) PROGRESSIVE PATTERN BRING FLOW AROUND TO THE SOUTHEAST 5-10KTS ON MONDAY...BEFORE INCREASING FROM THE SOUTH MONDAY NIGHT AHEAD OF THE NEXT FRONT. SOME TIMING DIFFERENCE BETWEEN MODELS...BUT APPEARS THAT THE ACTUAL WIND SHIFT WILL HOLD OFF UNTIL TUESDAY NIGHT...LEAVING WEST-SOUTHWEST WINDS 15-20KTS DURING THE DAY ON TUESDAY. ANOTHER...MORE PROLONGED NORTHWEST WINDS SURGE EXPECTED STARTING TUES NIGHT BEHIND FRONT. LIGHT WINDS WILL KEEP SEAS 2-4FT ON MONDAY...THOUGH THE STRONGER OFFSHORE COMPONENT INTO TUES WILL BUILD SEAS UP TO 6FT WELL OFFSHORE NORTH OF THE CAPE BY LATE TUE INTO WED. && .CLIMATE... RECORD HIGHS FOR TOMORROW... DAB 84 SET IN 1991 MCO 86 SET IN 1972 MLB 87 SET IN 1975 VRB 84 SET IN 1972 && .PRELIMINARY POINT TEMPS/POPS... DAB 65 83 55 66 / 20 50 40 0 MCO 64 83 58 71 / 20 40 40 0 MLB 70 84 63 70 / 20 30 40 0 VRB 69 84 65 71 / 20 30 30 0 LEE 65 80 55 68 / 20 50 40 0 SFB 65 83 57 70 / 20 50 40 0 ORL 65 82 58 71 / 20 40 40 0 FPR 68 84 65 71 / 20 30 30 0 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM...LASCODY IMPACT WX....BRAGAW
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
414 PM CST FRI JAN 10 2014 .DISCUSSION... 326 PM CST THE RAPIDLY EVOLVING NEXT 18 TO 24 HOURS APPEAR TO BE THE MOST CHALLENGING PORTION OF THE FORECAST FOR THE WEEKEND INTO NEXT WEEK. ISOLATED THUNDERSTORMS HAVE MOVED INTO THE AREA THIS AFTERNOON AND SUBFREEZING TEMPERATURES HAVE FOR THE MOST PART MOVED OUT...AT LEAST FOR THE TIME BEING. THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM INCLUDE DENSE FOG AND THE POSSIBLE NEED FOR AN ADVISORY LATER TONIGHT...THUNDERSTORM TRENDS AND COVERAGE...AND THE FLOOD POTENTIAL GIVEN THE EXPECTED RAINFALL AND WARMING TEMPERATURES. AS MENTIONED IN THE MORNING AFD UPDATE...THE FIRST QUESTION WOULD BE WHETHER DENSE FOG DEVELOPS IN THE SATURATED SURFACE LAYER MOVING IN OVER THE SNOWPACK WITH INCREASING DEWPOINTS. OBSERVATIONS JUST UPSTREAM OF THE AREA ARE SHOWING VSBYS AT WORST AROUND 1 MILE AND GENERALLY QUITE A BIT HIGHER...BUT FARTHER WEST AND SOUTHWEST TOWARD THE APPROACHING LOW CENTER THEY ARE MORE COMMONLY AROUND 1/4 TO 1/2 MILE. STILL AM NOT ANTICIPATING THE NEED FOR FOG HEADLINES IN THE IMMEDIATE TERM. WINDS IN THE TEENS AND MODERATE RAIN ACTUALLY SEEM TO BE HELPING THINGS AS WELL...BUT THE EVENING SHIFT WILL NEED TO REEVALUATE IN CASE CONDITIONS DETERIORATE AND A HEADLINE BECOMES NECESSARY LATE THIS EVENING OR OVERNIGHT. THE AREA OF THUNDERSTORMS SEEN EARLIER TODAY AROUND QUINCY HAS NOW MOVED INTO THE LOCAL AREA AS ANTICIPATED...IN CONJUNCTION WITH THE INCREASING LOW LEVEL MOISTURE FLUX DEPICTED IN THE RAP MODEL EAST OF THE APPROACHING LOW PRESSURE CENTER. AM NOT SEEING ANYTHING TO SUGGEST THIS ACTIVITY WILL BECOME WIDESPREAD THIS EVENING AS THE LOW LIFTS NORTHEAST...BUT WILL MAINTAIN A FIRST PERIOD MENTION OF ISOLATED TO SCATTERED THUNDERSTORMS MAINLY FOR THE SOUTHERN HALF OF THE AREA. AS FOR FLOODING POTENTIAL...HAVE BEEN CONSIDERING A FLOOD ADVISORY FOR URBAN AREAS WHERE RAIN MAY BE PONDING DUE TO DRAINS CLOGGED WITH ICE AND SNOW. AM NOT PLANNING ON ANY AREAL FLOOD WARNING HEADLINES AT THIS TIME GIVEN SO MANY VARIABLES...INCLUDING LOCATION OF HEAVIER RAIN AMOUNTS...DEGREE TO WHICH THE SNOWPACK WOULD SPONGE UP THE RAIN...EVOLUTION OF DEWPOINT TEMPERATURES...AND THE BEHAVIOR OF ICE ON THE RIVERS AND STREAMS. THE BEST POTENTIAL FOR MAINSTEM FLOODING STILL APPEARS TO BE LIMITED TO THE KANKAKEE WHERE A FLOOD WARNING WAS ISSUED EARLIER FOR ANTICIPATED MINOR FLOODING. THE OTHER RIVERS HAVE A LITTLE MORE ROOM TO HANDLE THE RUNOFF. FOR TONIGHT INTO TOMORROW MORNING...MAY TWEAK THE TIMING A BIT BUT AM NOT PLANNING ANY BIG CHANGES TO PRECIPITATION TRENDS. STILL EXPECTING MAINLY RAIN OVERNIGHT...EVOLVING TO DRIZZLE AND MAYBE A PERIOD OF LIGHT SNOW AS COLD AIR MOVES IN TOWARD MORNING. THE REMAINDER OF THE WEEKEND LOOKS DRY AND RELATIVELY MILD WITH SOUTHERLY WINDS AND CLEARING SKIES SUNDAY. NEXT WEEK BRINGS A RETURN TO SOMEWHAT MORE SEASONABLE...THOUGH STILL BELOW NORMAL...TEMPERATURES AND MULTIPLE PERIODS OF LIGHT SNOW POTENTIAL CORRESPONDING TO COLD FRONTAL PASSAGES. THE PRIMARY SURFACE CYCLONE TRACK APPEARS TO STAY NORTH OF THE LOCAL AREA. THE MOST PRONOUNCED COLD AIR INTRUSION LOOKS POISED TO ARRIVE LATE IN THE WEEK...POTENTIALLY KEEPING HIGHS ONLY IN THE TEENS NEXT FRIDAY. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * LOW CEILINGS CONTINUING THROUGH THE REST OF THE DAY...IMPROVING BEHIND COLD FRONT EARLY TOMORROW. * VSBY GENERALLY 1-3SM...BUT POSSIBLY LESS THAN A QUARTER MILE IF DENSE FOG WERE TO DEVELOP. MDB //DISCUSSION...UPDATED 22Z... LIGHT TO MODERATE AND OCCASIONALLY HEAVY RAIN CONTINUES TO MOVE ACROSS THE TERMINALS AND WILL CONTINUE TO DO SO INTO THE EARLY EVENING. OBSERVATIONS SHOW A RANGE OF VISIBILITY GENERALLY IN THE 1-3SM RANGE WITH SOME SPOTS SLIGHTLY HIGHER. CIGS HAVE VARIED TO MVFR AT TIMES IN SPOTS LIKELY DUE TO SOME EARLIER CONVECTIVE/THUNDER ELEMENTS...BUT A MORE UNIFORM IFR/LIFR LAYER IS EXPECTED TO PERSIST. STEADIER RAIN LOOKS TO BEGIN TO EXIT THE AREA FROM THE WEST EARLY THIS EVENING. STILL MONITORING FOR DENSE FOG POTENTIAL AS THE RAIN ENDS BUT WILL LEAVE VSBY AT 1SM FOR NOW THIS EVENING/EARLY TONIGHT WITH THE WORST VISIBILITY POSSIBLY PASSING TO THE WEST. MDB FROM 18Z... A WASHED OUT WARM FRONT IS LIFTING INTO ILLINOIS EARLY THIS AFTERNOON...WITH A BROAD DEWPOINT GRADIENT SPREADING NORTHWARD ACROSS THE STATE. NORTH OF THE FRONT...CIGS ARE GENERALLY BETWEEN 002 AND 005 WHILE VSBY IS MORE VARIABLE...BUT NUMEROUS 1-3SM REPORTS ARE NOTED ACROSS FAR NORTHERN ILLINOIS DUE TO FOG/MIST. AS LOW PRESSURE TRACKS FROM EASTERN NEBRASKA THIS AFTERNOON INTO SOUTHERN WISCONSIN LATER THIS EVENING...EXPECT NORTHWARD MOISTURE TRANSPORT TO CONTINUE WITH DEWPOINTS RISING INTO THE MID OR UPPER 30S OVER THE SNOWPACK. THE IMMEDIATE CONCERN HERE IS FOR THE POTENTIAL OF DENSE FOG DEVELOPING...WITH MET GUIDANCE INDICATING VSBY TANKING THIS AFTERNOON. FEEL GUIDANCE MAY BE HITTING THIS TOO HARD THOUGH GIVEN THE BROAD TD GRADIENT...AND WILL LEAN TOWARDS A MORE OPTIMISTIC VSBY FORECAST...ADMITTEDLY WITH LOW CONFIDENCE CONSIDERING THE MORE WIDESPREAD 1/4 TO 1/2 SM VSBY IMMEDIATELY AHEAD OF THE LOW. SHOWERS WILL OVERSPREAD THE AREA THIS AFTERNOON AS A POTENT UPPER WAVE LIFTS ACROSS THE REGION. MID LEVEL LAPSE RATES MAY BE SUFFICIENTLY STEEP ENOUGH TO SUPPORT EMBEDDED THUNDERSTORMS AS FAR NORTH AS THE CHICAGO TERMINALS...HOWEVER FELL BEST CHANCES FOR FOR THUNDER WILL STAY SOUTH OF THE I-80 CORRIDOR. RAIN IS EXPECTED TO BE MODERATE WITH BRIEFLY HEAVY SHOWERS POSSIBLE. DEEPER MOISTURE WILL PUSH OUT OF THE AREA MID TO LATE THIS EVENING WITH LINGERING DRIZZLE POSSIBLE INTO THE EARLY OVERNIGHT HOURS. FEEL THAT ONCE THE RAIN STOPS THIS EVENING...THIS WILL BE THE PERIOD THAT MAY HAVE TO BE MONITORED MOST CLOSELY FOR FOG DEVELOPING. DEWPOINTS SHOULD BE CLIMBING INTO THE 35-37 RANGE BY THIS POINT WHICH ASSUMING THERE IS STILL SOME SNOW ON THE GROUND WOULD BE FAVORABLE FOR FOG TO INCREASE IN THICKNESS. UNFORTUNATELY...MET/MAV GUIDANCE SHOWS THE OPPOSITE...WITH IMPROVING VSBY TRENDS AFTER THE RAIN DEPARTS OVERNIGHT...ONCE AGAIN RESULTING IN VERY LOW CONFIDENCE IN VSBY FCST. WILL STICK WITH GOING VSBY TRENDS THIS PERIOD UNTIL HAVE HIGHER CONFIDENCE IN A SOLUTION. A COLD FRONT WILL SWEEP ACROSS THE AREA EARLY SATURDAY. WHILE NOTABLE DRYING OCCURS ALOFT...APPEARS WE MAY STICK FOR SEVERAL HOURS WITH SOME POST FRONTAL STRATUS...AT LEAST UNTIL SATURDAY AFTERNOON WHEN IT MAY FINALLY SCATTER OUT. VSBY SHOULD SHARPLY IMPROVE BEHIND THE FRONT THOUGH WITH WINDS TURNING WESTERLY AND BECOMING INCREASINGLY GUSTY. BMD //ORD AND MDW CONFIDENCE...UPDATED 22Z... * LOW CONFIDENCE IN VSBY TRENDS THROUGH TONIGHT. * HIGH CONFIDENCE IN IFR OR LOWER CIGS THROUGH THE OVERNIGHT HOURS. * HIGH CONFIDENCE IN RAIN TIMING. * MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...MEDIUM CONFIDENCE IN WIND SPEED. MDB //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT...VFR PROBABLE. SUNDAY...STRONG SOUTH WINDS...LLWS POSSIBLE AFTERNOON/EARLY EVENING. VFR PROBABLE. MONDAY...VFR. TUESDAY...CHANCE OF SNOW/IFR. WEDNESDAY AND THURSDAY...VFR PROBABLE. IZZI && .MARINE... 209 PM CST LARGE DOME OF HIGH PRESSURE OVER THE EASTERN SEABOARD HAS DRIFTED EAST...AND STRETCHES FROM CENTRAL QUEBEC SOUTH THROUGH THE CAROLINA COAST. MEANWHILE ACROSS THE CENTRAL PLAINS A SERIES OF LOW PRESSURES EXISTED...WITH ONE ACROSS THE NORTHERN PLAINS AND THE SECOND ACROSS THE CENTRAL PLAINS. THESE TWO AREAS OF LOW PRESSURES WILL CONVERGE UPON LAKE MICHIGAN...CONSOLIDATING INTO A SLIGHTLY STRONGER LOW PRESSURE OVER THE NORTHERN PORTION OF LAKE MICHIGAN EARLY SATURDAY MORNING. WINDS FOR MUCH OF THE LAKE WILL REMAIN SOUTHERLY...WITH THE FAR NORTHERN PORTIONS NEAR THE STRAITS OF MACKINAW BEING SLIGHTLY SOUTHEAST/EAST. THEN WITH THE LOW PASSAGE EXPECTED TO OCCUR SATURDAY MORNING WITH A TRAILING FRONTAL BOUNDARY SLIDING EAST ACROSS THE LAKE...THE GRADIENT IS EXPECTED TO TIGHTEN. FOR THE CENTRAL/SOUTHERN PORTIONS WINDS WILL INCREASE TO NEAR 30 KT BY MIDDAY/EARLY AFTN SAT. THEN AS THE FRONTAL BOUNDARY CONTINUES TO PRESS EAST...WINDS WILL TURN MORE TO THE WEST. FOR THE NORTHERN HALF OF THE LAKE WINDS FOR A PERIOD WILL BECOME NORTHWEST...BEFORE RELAXING TO THE WEST SAT LATE AFTN. HIGH PRESSURE ACROSS THE SOUTHERN PLAINS SAT AFTN WILL CONTINUE TO SLIDE EAST...STRETCHING AN INFLUENCE NORTH TO LAKE MICHIGAN SATURDAY NIGHT/EARLY SUN. THIS COUPLED WITH YET ANOTHER LOW PRESSURE SYSTEM BEGINNING TO PUSH INTO CENTRAL CANADA...WILL ALLOW THE GRADIENT TO TIGHTEN. WINDS SHOULD REMAIN BREEZY SUN AFTN/EVE. THE GRADIENT HAS BECOME SLIGHTLY TIGHTER...ALONG WITH THE LOW PRESSURE BECOME DEEPER TO 28.9 INCHES JUST NORTH OF LAKE SUPERIOR SUN EVE. THIS WILL LIKELY CREATE A PERIOD OF GALES FOR THE LAKE DURING THE SUN AFTN/EVE TIMEFRAME. THE GRADIENT THEN BEGINS TO SLACKEN OFF FOR THE MIDDLE OF NEXT WEEK...WITH JUST A COUPLE WEAK WAVES TRAVERSING THE WESTERN GREAT LAKES REGION. IN THE LONGER RANGE PERIODS FORECAST GUIDANCE IS BEGINNING TO INDICATE A STRENGTHENING LOW PRESSURE OVER THE OHIO VALLEY TUE NIGHT...WHICH COULD RESULT IN A TIGHTENING GRADIENT FOR LAKE MICHIGAN WED AND BREEZY CONDITIONS RETURNING. BEACHLER && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
326 PM CST FRI JAN 10 2014 .DISCUSSION... 326 PM CST THE RAPIDLY EVOLVING NEXT 18 TO 24 HOURS APPEAR TO BE THE MOST CHALLENGING PORTION OF THE FORECAST FOR THE WEEKEND INTO NEXT WEEK. ISOLATED THUNDERSTORMS HAVE MOVED INTO THE AREA THIS AFTERNOON AND SUBFREEZING TEMPERATURES HAVE FOR THE MOST PART MOVED OUT...AT LEAST FOR THE TIME BEING. THE PRIMARY FORECAST CONCERNS IN THE NEAR TERM INCLUDE DENSE FOG AND THE POSSIBLE NEED FOR AN ADVISORY LATER TONIGHT...THUNDERSTORM TRENDS AND COVERAGE...AND THE FLOOD POTENTIAL GIVEN THE EXPECTED RAINFALL AND WARMING TEMPERATURES. AS MENTIONED IN THE MORNING AFD UPDATE...THE FIRST QUESTION WOULD BE WHETHER DENSE FOG DEVELOPS IN THE SATURATED SURFACE LAYER MOVING IN OVER THE SNOWPACK WITH INCREASING DEWPOINTS. OBSERVATIONS JUST UPSTREAM OF THE AREA ARE SHOWING VSBYS AT WORST AROUND 1 MILE AND GENERALLY QUITE A BIT HIGHER...BUT FARTHER WEST AND SOUTHWEST TOWARD THE APPROACHING LOW CENTER THEY ARE MORE COMMONLY AROUND 1/4 TO 1/2 MILE. STILL AM NOT ANTICIPATING THE NEED FOR FOG HEADLINES IN THE IMMEDIATE TERM. WINDS IN THE TEENS AND MODERATE RAIN ACTUALLY SEEM TO BE HELPING THINGS AS WELL...BUT THE EVENING SHIFT WILL NEED TO REEVALUATE IN CASE CONDITIONS DETERIORATE AND A HEADLINE BECOMES NECESSARY LATE THIS EVENING OR OVERNIGHT. THE AREA OF THUNDERSTORMS SEEN EARLIER TODAY AROUND QUINCY HAS NOW MOVED INTO THE LOCAL AREA AS ANTICIPATED...IN CONJUNCTION WITH THE INCREASING LOW LEVEL MOISTURE FLUX DEPICTED IN THE RAP MODEL EAST OF THE APPROACHING LOW PRESSURE CENTER. AM NOT SEEING ANYTHING TO SUGGEST THIS ACTIVITY WILL BECOME WIDESPREAD THIS EVENING AS THE LOW LIFTS NORTHEAST...BUT WILL MAINTAIN A FIRST PERIOD MENTION OF ISOLATED TO SCATTERED THUNDERSTORMS MAINLY FOR THE SOUTHERN HALF OF THE AREA. AS FOR FLOODING POTENTIAL...HAVE BEEN CONSIDERING A FLOOD ADVISORY FOR URBAN AREAS WHERE RAIN MAY BE PONDING DUE TO DRAINS CLOGGED WITH ICE AND SNOW. AM NOT PLANNING ON ANY AREAL FLOOD WARNING HEADLINES AT THIS TIME GIVEN SO MANY VARIABLES...INCLUDING LOCATION OF HEAVIER RAIN AMOUNTS...DEGREE TO WHICH THE SNOWPACK WOULD SPONGE UP THE RAIN...EVOLUTION OF DEWPOINT TEMPERATURES...AND THE BEHAVIOR OF ICE ON THE RIVERS AND STREAMS. THE BEST POTENTIAL FOR MAINSTEM FLOODING STILL APPEARS TO BE LIMITED TO THE KANKAKEE WHERE A FLOOD WARNING WAS ISSUED EARLIER FOR ANTICIPATED MINOR FLOODING. THE OTHER RIVERS HAVE A LITTLE MORE ROOM TO HANDLE THE RUNOFF. FOR TONIGHT INTO TOMORROW MORNING...MAY TWEAK THE TIMING A BIT BUT AM NOT PLANNING ANY BIG CHANGES TO PRECIPITATION TRENDS. STILL EXPECTING MAINLY RAIN OVERNIGHT...EVOLVING TO DRIZZLE AND MAYBE A PERIOD OF LIGHT SNOW AS COLD AIR MOVES IN TOWARD MORNING. THE REMAINDER OF THE WEEKEND LOOKS DRY AND RELATIVELY MILD WITH SOUTHERLY WINDS AND CLEARING SKIES SUNDAY. NEXT WEEK BRINGS A RETURN TO SOMEWHAT MORE SEASONABLE...THOUGH STILL BELOW NORMAL...TEMPERATURES AND MULTIPLE PERIODS OF LIGHT SNOW POTENTIAL CORRESPONDING TO COLD FRONTAL PASSAGES. THE PRIMARY SURFACE CYCLONE TRACK APPEARS TO STAY NORTH OF THE LOCAL AREA. THE MOST PRONOUNCED COLD AIR INTRUSION LOOKS POISED TO ARRIVE LATE IN THE WEEK...POTENTIALLY KEEPING HIGHS ONLY IN THE TEENS NEXT FRIDAY. LENNING && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LOW CEILINGS CONTINUING THROUGH THE REST OF THE DAY...IMPROVING BEHIND COLD FRONT EARLY TOMORROW. * VSBY GENERALLY 1-3SM...BUT POSSIBLY LESS THAN A QUARTER MILE IF DENSE FOG WERE TO DEVELOP. BMD //DISCUSSION...UPDATED 18Z... A WASHED OUT WARM FRONT IS LIFTING INTO ILLINOIS EARLY THIS AFTERNOON...WITH A BROAD DEWPOINT GRADIENT SPREADING NORTHWARD ACROSS THE STATE. NORTH OF THE FRONT...CIGS ARE GENERALLY BETWEEN 002 AND 005 WHILE VSBY IS MORE VARIABLE...BUT NUMEROUS 1-3SM REPORTS ARE NOTED ACROSS FAR NORTHERN ILLINOIS DUE TO FOG/MIST. AS LOW PRESSURE TRACKS FROM EASTERN NEBRASKA THIS AFTERNOON INTO SOUTHERN WISCONSIN LATER THIS EVENING...EXPECT NORTHWARD MOISTURE TRANSPORT TO CONTINUE WITH DEWPOINTS RISING INTO THE MID OR UPPER 30S OVER THE SNOWPACK. THE IMMEDIATE CONCERN HERE IS FOR THE POTENTIAL OF DENSE FOG DEVELOPING...WITH MET GUIDANCE INDICATING VSBY TANKING THIS AFTERNOON. FEEL GUIDANCE MAY BE HITTING THIS TOO HARD THOUGH GIVEN THE BROAD TD GRADIENT...AND WILL LEAN TOWARDS A MORE OPTIMISTIC VSBY FORECAST...ADMITTEDLY WITH LOW CONFIDENCE CONSIDERING THE MORE WIDESPREAD 1/4 TO 1/2 SM VSBY IMMEDIATELY AHEAD OF THE LOW. SHOWERS WILL OVERSPREAD THE AREA THIS AFTERNOON AS A POTENT UPPER WAVE LIFTS ACROSS THE REGION. MID LEVEL LAPSE RATES MAY BE SUFFICIENTLY STEEP ENOUGH TO SUPPORT EMBEDDED THUNDERSTORMS AS FAR NORTH AS THE CHICAGO TERMINALS...HOWEVER FELL BEST CHANCES FOR FOR THUNDER WILL STAY SOUTH OF THE I-80 CORRIDOR. RAIN IS EXPECTED TO BE MODERATE WITH BRIEFLY HEAVY SHOWERS POSSIBLE. DEEPER MOISTURE WILL PUSH OUT OF THE AREA MID TO LATE THIS EVENING WITH LINGERING DRIZZLE POSSIBLE INTO THE EARLY OVERNIGHT HOURS. FEEL THAT ONCE THE RAIN STOPS THIS EVENING...THIS WILL BE THE PERIOD THAT MAY HAVE TO BE MONITORED MOST CLOSELY FOR FOG DEVELOPING. DEWPOINTS SHOULD BE CLIMBING INTO THE 35-37 RANGE BY THIS POINT WHICH ASSUMING THERE IS STILL SOME SNOW ON THE GROUND WOULD BE FAVORABLE FOR FOG TO INCREASE IN THICKNESS. UNFORTUNATELY...MET/MAV GUIDANCE SHOWS THE OPPOSITE...WITH IMPROVING VSBY TRENDS AFTER THE RAIN DEPARTS OVERNIGHT...ONCE AGAIN RESULTING IN VERY LOW CONFIDENCE IN VSBY FCST. WILL STICK WITH GOING VSBY TRENDS THIS PERIOD UNTIL HAVE HIGHER CONFIDENCE IN A SOLUTION. A COLD FRONT WILL SWEEP ACROSS THE AREA EARLY SATURDAY. WHILE NOTABLE DRYING OCCURS ALOFT...APPEARS WE MAY STICK FOR SEVERAL HOURS WITH SOME POST FRONTAL STRATUS...AT LEAST UNTIL SATURDAY AFTERNOON WHEN IT MAY FINALLY SCATTER OUT. VSBY SHOULD SHARPLY IMPROVE BEHIND THE FRONT THOUGH WITH WINDS TURNING WESTERLY AND BECOMING INCREASINGLY GUSTY. BMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * VERY LOW CONFIDENCE IN VSBY TRENDS TODAY AND TONIGHT. * HIGH CONFIDENCE IN IFR OR LOWER CIGS THROUGH THE OVERNIGHT HOURS. * HIGH CONFIDENCE IN RAIN TIMING. * MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...MEDIUM CONFIDENCE IN WIND SPEED. BMD //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT...VFR PROBABLE. SUNDAY...STRONG SOUTH WINDS...LLWS POSSIBLE AFTERNOON/EARLY EVENING. VFR PROBABLE. MONDAY...VFR. TUESDAY...CHANCE OF SNOW/IFR. WEDNESDAY AND THURSDAY...VFR PROBABLE. IZZI && .MARINE... 209 PM CST LARGE DOME OF HIGH PRESSURE OVER THE EASTERN SEABOARD HAS DRIFTED EAST...AND STRETCHES FROM CENTRAL QUEBEC SOUTH THROUGH THE CAROLINA COAST. MEANWHILE ACROSS THE CENTRAL PLAINS A SERIES OF LOW PRESSURES EXISTED...WITH ONE ACROSS THE NORTHERN PLAINS AND THE SECOND ACROSS THE CENTRAL PLAINS. THESE TWO AREAS OF LOW PRESSURES WILL CONVERGE UPON LAKE MICHIGAN...CONSOLIDATING INTO A SLIGHTLY STRONGER LOW PRESSURE OVER THE NORTHERN PORTION OF LAKE MICHIGAN EARLY SATURDAY MORNING. WINDS FOR MUCH OF THE LAKE WILL REMAIN SOUTHERLY...WITH THE FAR NORTHERN PORTIONS NEAR THE STRAITS OF MACKINAW BEING SLIGHTLY SOUTHEAST/EAST. THEN WITH THE LOW PASSAGE EXPECTED TO OCCUR SATURDAY MORNING WITH A TRAILING FRONTAL BOUNDARY SLIDING EAST ACROSS THE LAKE...THE GRADIENT IS EXPECTED TO TIGHTEN. FOR THE CENTRAL/SOUTHERN PORTIONS WINDS WILL INCREASE TO NEAR 30 KT BY MIDDAY/EARLY AFTN SAT. THEN AS THE FRONTAL BOUNDARY CONTINUES TO PRESS EAST...WINDS WILL TURN MORE TO THE WEST. FOR THE NORTHERN HALF OF THE LAKE WINDS FOR A PERIOD WILL BECOME NORTHWEST...BEFORE RELAXING TO THE WEST SAT LATE AFTN. HIGH PRESSURE ACROSS THE SOUTHERN PLAINS SAT AFTN WILL CONTINUE TO SLIDE EAST...STRETCHING AN INFLUENCE NORTH TO LAKE MICHIGAN SATURDAY NIGHT/EARLY SUN. THIS COUPLED WITH YET ANOTHER LOW PRESSURE SYSTEM BEGINNING TO PUSH INTO CENTRAL CANADA...WILL ALLOW THE GRADIENT TO TIGHTEN. WINDS SHOULD REMAIN BREEZY SUN AFTN/EVE. THE GRADIENT HAS BECOME SLIGHTLY TIGHTER...ALONG WITH THE LOW PRESSURE BECOME DEEPER TO 28.9 INCHES JUST NORTH OF LAKE SUPERIOR SUN EVE. THIS WILL LIKELY CREATE A PERIOD OF GALES FOR THE LAKE DURING THE SUN AFTN/EVE TIMEFRAME. THE GRADIENT THEN BEGINS TO SLACKEN OFF FOR THE MIDDLE OF NEXT WEEK...WITH JUST A COUPLE WEAK WAVES TRAVERSING THE WESTERN GREAT LAKES REGION. IN THE LONGER RANGE PERIODS FORECAST GUIDANCE IS BEGINNING TO INDICATE A STRENGTHENING LOW PRESSURE OVER THE OHIO VALLEY TUE NIGHT...WHICH COULD RESULT IN A TIGHTENING GRADIENT FOR LAKE MICHIGAN WED AND BREEZY CONDITIONS RETURNING. BEACHLER && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
209 PM CST FRI JAN 10 2014 .DISCUSSION... 1114 AM CST HAVE SPENT THE MORNING EXAMINING THE POTENTIAL FOR DENSE FOG AND THE POSSIBLE NEED FOR AN ADVISORY LATER TODAY...THE APPROACHING THUNDERSTORMS IN WEST CENTRAL ILLINOIS...AND THE FLOOD POTENTIAL GIVEN THE EXPECTED RAINFALL AND WARMING TEMPERATURES. FOR THE NEAR TERM WE ELECTED TO CANCEL THE FREEZING FOG ADVISORY A LITTLE EARLY AS TEMPERATURES IN MOST LOCATIONS HAVE RISEN ABOVE OR VERY NEAR FREEZING. THE NEXT QUESTION WOULD BE WHETHER DENSE FOG DEVELOPS IN THE SATURATED SURFACE LAYER MOVING IN OVER THE SNOWPACK WITH INCREASING DEWPOINTS. OBSERVATIONS JUST UPSTREAM OF THE AREA ARE SHOWING VSBYS AT WORST AROUND 1 MILE...BUT FARTHER UPSTREAM TOWARD THE APPROACHING LOW CENTER THEY ARE MORE COMMONLY AROUND 1/4 TO 1/2 MILE. SO FOR THE AFTERNOON AM NOT ANTICIPATING THE NEED FOR FOG HEADLINES...BUT WILL REEVALUATE LATER TODAY IN CASE SOMETHING MAY BE NEEDED THIS EVENING OR OVERNIGHT. THE AREA OF THUNDERSTORMS AROUND QUINCY AND SOUTHWEST TOWARD JOPLIN MISSOURI IS WELL CORRELATED WITH AN AREA OF ENHANCED LOW LEVEL MOISTURE FLUX SHOWN IN THE RAP MODEL EAST OF THE APPROACHING LOW PRESSURE CENTER. AS THE AFTERNOON EVOLVES AND THE LOW LIFTS NORTHEAST...THE RAP MODEL INCREASES THE MOISTURE FLUX OVER CENTRAL AND NORTHERN ILLINOIS. AREAS OF STEEPER LAPSE RATES ARE ALSO SEEN IN NAM/GFS SOUNDINGS FOR THE AFTERNOON AND EVENING TIMEFRAME. WILL UPDATE FCST GRIDS TO INTRODUCE A SLIGHT CHANCE OF TSTMS MAINLY FOR THE SOUTHERN HALF OF THE AREA. AS FOR FLOODING POTENTIAL...AM NOT PLANNING ON ANY FLOOD WATCH HEADLINES AT THIS TIME GIVEN SO MANY VARIABLES...INCLUDING LOCATION OF HEAVIER RAIN AMOUNTS...DEGREE TO WHICH THE SNOWPACK WOULD SPONGE UP THE RAIN...EVOLUTION OF DEWPOINT TEMPERATURES...AND THE BEHAVIOR OF ICE ON THE RIVERS AND STREAMS. THE BEST POTENTIAL FOR MAINSTEM FLOODING APPEARS TO BE ALONG THE KANKAKEE WHERE A FLOOD WARNING HAS BEEN ISSUED FOR ANTICIPATED MINOR FLOODING. THIS RIVER ALREADY HAD QUITE A BIT OF WATER IN IT...BUT THE OTHERS HAVE A LITTLE MORE ROOM TO HANDLE THE RUNOFF. LENNING //PREV DISCUSSION... 338 AM CST SHORT TERM...TODAY THROUGH SUNDAY NIGHT TODAY/TONIGHT... MULTIPLE CONCERNS IN THE NEAR TERM TODAY...INCLUDING DENSE FOG...FREEZING DRIZZLE/RAIN AND THEN RAIN AND MELTING SNOW LATER TODAY INTO THIS EVENING. GRADUAL INCREASE IN SURFACE MOISTURE OVER DEEP SNOW PACK HAS RESULTED IN FOG DEVELOPMENT EARLY THIS MORNING...WITH MULTIPLE LOCATIONS AOB 1/2 MILE. FOG HAS BEEN MOST DENSE ALONG/WEST OF A LINE FROM UGN TO VYS. WILL LIKELY NEED A DENSE FOG ADVISORY ADVISORY OR FREEZING FOG ADVISORY FOR MOST IF NOT ALL IF THIS AREA FOR PART OF TODAY UNTIL TEMPERATURES WARM AND STEADIER PRECIP ARRIVES LATER...WITH CONTINUED MOISTURE INCREASE AND SATURATION OF SURFACE LAYER OVER SNOWPACK. WEAK ASCENT EARLY TO MID MORNING IN SOUTHWEST FLOW ALOFT WITH INCOMING SHORTWAVE ENERGY COULD ALSO RESULT IN PATCHY FREEZING DRIZZLE...BEST CHANCE OF SEEING MEASURABLE ZR- IN WESTERN HALF OF CWA...BUT CONFIDENCE IS LOW IN ICE ACCUMULATIONS. TEMPERATURE TRENDS WILL BE KEY TO EXTENT OF PROBLEMS TODAY WITH FREEZING RAIN/DRIZZLE. UNTIL BETTER DEWPOINTS SOUTH OF OH RIVER SURGE NORTHWARD...TEMPERATURES SHOULD VERY SLOWLY CLIMB. GUIDANCE IS ALREADY A BIT TOO LOW ON CURRENT TEMPERATURES...SO THINK THAT ONCE STRONGER MIDLEVEL WAVE/MOIST TRANSPORT ARRIVES EARLY TO MID AFTERNOON...MOST IF NOT ALL AREAS SHOULD BE ABOVE FREEZING AND LIMIT FREEZING RAIN THREAT. BIGGEST CONCERN IS FOR WI BORDER AREAS TO WARM A BIT SLOWER AND THUS SEE A FEW HRS OF FREEZING RAIN BEFORE CHANGING TO PLAIN RAIN. HAVE BETTER CONFIDENCE ROUGHLY SOUTH OF I-90 THAT PLAIN RAIN WILL BE PREDOMINANT P-TYPE. REGARDING RAIN AND SNOWMELT...STOUT MIDLEVEL WAVE AND ASSOCIATED SURFACE LOW TRACKING WEST OF CWA WILL AIM PLUME OF 2-3 SD ABOVE NORMAL/A BIT OVER .75 INCH PWAT/INTO AREA BY THIS EVENING. UNTIL DRYSLOT ARRIVES LATE IN THE EVENING INTO THE OVERNIGHT AND SHUTS OFF STEADY RAIN...THERE COULD BE PERIODS OF MODERATE RAIN. LOCAL WRF GUIDANCE IS MUCH MORE BULLISH ON HOW WARM TEMPERATURES ARE THIS EVENING/MID 40S FOR SOUTHEASTERN HALF OF CWA/WITH HEAVIEST RAINFALL. IF TEMPERATURES ARE WARMER THAN UPPER 30S/LOW 40S/THIS COULD ENABLE MORE RAPID SNOWMELT AND HEIGHTEN FLOODING CONCERNS. DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE ANY FLOOD WATCHES...BUT WILL CONTINUE WITH PREVIOUSLY ISSUED ESF TO HIGHLIGHT FLOODING POTENTIAL...INCLUDING BREAK UP ICE JAMS ON AREA RIVERS. SATURDAY THROUGH SUNDAY NIGHT... LOWERED POPS SATURDAY MORNING...WITH ONLY CHANCE POPS FOR FAR NORTH AS DEFORMATION AXIS OF STRENGTHENING SURFACE AND UPPER SYSTEM OVER THE REGION LOOKS TO AT BEST GRAZE THE FAR NORTH. MORE LIKELY SCENARIO IS FOR DEFORMATION TO IMPACT CENTRAL WISCONSIN. THEREFORE...WHILE THERMAL PROFILES WILL BECOME COLD ENOUGH...AT BEST WOULD ONLY EXPECT LIGHT SNOW AND NO ACCUM IN FAR NORTHERN CWA. COOL ADVECTION THROUGH THE DAY WILL RESULT IN ONLY A FEW DEGREE TEMP CLIMB IN AFTERNOON FROM MORNING LOWS IN LOW-MID 30S. THERE SHOULD BE ENOUGH TIME FOR WET SURFACES TO DRY OFF TO PRECLUDE A BIG THREAT OF ICY SPOTS ON ROAD SURFACES SATURDAY NIGHT AS TEMPERATURES FALL INTO THE TEENS AND 20S. RAPID WARM ADVECTION PATTERN THEN SETS UP ON SUNDAY AS H85 TEMPS WARM BACK UP TO +6 TO +8C. A LOOK AT FORECAST SOUNDINGS INDICATES THAT GLOBAL MODELS MAY BE STRUGGLING WITH LOWER LEVEL THERMAL PROFILES DUE TO TRYING TO RESOLVE EXISTING SNOWPACK. AS A RESULT...925 MB TEMPS ON HIGHER RES NAM OF +6 TO +8C MAY BE THE BETTER ROUTE THAN LOW POSITIVE SINGLE DIGITS. ASSUMING THAT MOST OF THE AREA STILL HAS AT LEAST 1 INCH OF SNOW ON THE GROUND...WARMING POTENTIAL WILL BE LESS THAN WITHOUT SNOW. HOWEVER...SOUTHERN EDGE OF SNOWPACK WILL LIKELY BE QUICKLY ERODING...WITH MID 40S IF NOT WARMER POSSIBLE IN SOUTHERN CWA. ONLY AREAS LIMITED TO THE UPPER 30S MAY BE THE FAR NORTHWEST. A COLD FRONT TRAILING FROM CLIPPER SYSTEM OVER NORTHERN LAKES WILL THEN SWING THROUGH CWA SUNDAY NIGHT LIKELY DRY EXCEPT PERHAPS FAR NORTH WHERE SLIGHT POPS WERE MAINTAINED. LONG TERM...MONDAY THROUGH THURSDAY... OVERALL UPPER PATTERN WILL REALIGN TO A RIDGE IN THE WEST/TROUGH IN THE EAST...WHICH IS KNOWN AS A POSITIVE PNA PATTERN. THIS IS TYPICALLY A COLDER BUT FAIRLY DRY SET-UP FOR THE LOCAL AREA. WILL NEED TO WATCH FOR CLIPPER TYPE SYSTEMS IN NORTHWEST FLOW ALOFT. GUIDANCE BECOMES SPLIT ON WHETHER TO FOCUS MORE ENERGY IN SOUTHERN STREAM SYSTEM OR NORTHERN VORT ON MONDAY NIGHT INTO TUESDAY. IN PARTICULAR...ECMWF IS OF MOST INTEREST WITH ITS STRONGER SOUTHERN STREAM WAVE. IF A QUICKER PHASE OCCURS WITH NORTHERN BRANCH FEATURE...MORE THAN SOUTHEAST CWA COULD BE IMPACTED BY A SYSTEM IN THIS TIMEFRAME. OPERATIONAL GFS DOES NOT SEEM TO HAVE MUCH ENSEMBLE SUPPORT WITH ITS UNUSUALLY STRONG CLIPPER SYSTEM TRACKING ACROSS THE AREA ON MONDAY NIGHT. HAVE SLIGHT TO LOW POPS MONDAY NIGHT INTO TUESDAY...WITH THE POSSIBILITY THEN OF MORE CLIPPER ACITIVITY LATER NEXT WEEK. IN BETWEEN LOOKS TO BE PRIMARILY DRY...WITH LAKE EFFECT SNOW FOCUSED EAST OF FAR EASTERN CWA. THE CORE OF THE COLDEST AIR DURING THIS TIME WILL REMAIN NORTH OF US WITH POLAR VORTEX OVER HUDSON BAY...BUT OTHER THAN A BRIEF WARM-UP ON THURSDAY...TEMPERATURES ARE LIKELY TO AVERAGE BELOW NORMAL THROUGH EXTENDED AND BEYOND. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LOW CEILINGS CONTINUING THROUGH THE REST OF THE DAY...IMPROVING BEHIND COLD FRONT EARLY TOMORROW. * VSBY GENERALLY 1-3SM...BUT POSSIBLY LESS THAN A QUARTER MILE IF DENSE FOG WERE TO DEVELOP. BMD //DISCUSSION...UPDATED 18Z... A WASHED OUT WARM FRONT IS LIFTING INTO ILLINOIS EARLY THIS AFTERNOON...WITH A BROAD DEWPOINT GRADIENT SPREADING NORTHWARD ACROSS THE STATE. NORTH OF THE FRONT...CIGS ARE GENERALLY BETWEEN 002 AND 005 WHILE VSBY IS MORE VARIABLE...BUT NUMEROUS 1-3SM REPORTS ARE NOTED ACROSS FAR NORTHERN ILLINOIS DUE TO FOG/MIST. AS LOW PRESSURE TRACKS FROM EASTERN NEBRASKA THIS AFTERNOON INTO SOUTHERN WISCONSIN LATER THIS EVENING...EXPECT NORTHWARD MOISTURE TRANSPORT TO CONTINUE WITH DEWPOINTS RISING INTO THE MID OR UPPER 30S OVER THE SNOWPACK. THE IMMEDIATE CONCERN HERE IS FOR THE POTENTIAL OF DENSE FOG DEVELOPING...WITH MET GUIDANCE INDICATING VSBY TANKING THIS AFTERNOON. FEEL GUIDANCE MAY BE HITTING THIS TOO HARD THOUGH GIVEN THE BROAD TD GRADIENT...AND WILL LEAN TOWARDS A MORE OPTIMISTIC VSBY FORECAST...ADMITTEDLY WITH LOW CONFIDENCE CONSIDERING THE MORE WIDESPREAD 1/4 TO 1/2 SM VSBY IMMEDIATELY AHEAD OF THE LOW. SHOWERS WILL OVERSPREAD THE AREA THIS AFTERNOON AS A POTENT UPPER WAVE LIFTS ACROSS THE REGION. MID LEVEL LAPSE RATES MAY BE SUFFICIENTLY STEEP ENOUGH TO SUPPORT EMBEDDED THUNDERSTORMS AS FAR NORTH AS THE CHICAGO TERMINALS...HOWEVER FELL BEST CHANCES FOR FOR THUNDER WILL STAY SOUTH OF THE I-80 CORRIDOR. RAIN IS EXPECTED TO BE MODERATE WITH BRIEFLY HEAVY SHOWERS POSSIBLE. DEEPER MOISTURE WILL PUSH OUT OF THE AREA MID TO LATE THIS EVENING WITH LINGERING DRIZZLE POSSIBLE INTO THE EARLY OVERNIGHT HOURS. FEEL THAT ONCE THE RAIN STOPS THIS EVENING...THIS WILL BE THE PERIOD THAT MAY HAVE TO BE MONITORED MOST CLOSELY FOR FOG DEVELOPING. DEWPOINTS SHOULD BE CLIMBING INTO THE 35-37 RANGE BY THIS POINT WHICH ASSUMING THERE IS STILL SOME SNOW ON THE GROUND WOULD BE FAVORABLE FOR FOG TO INCREASE IN THICKNESS. UNFORTUNATELY...MET/MAV GUIDANCE SHOWS THE OPPOSITE...WITH IMPROVING VSBY TRENDS AFTER THE RAIN DEPARTS OVERNIGHT...ONCE AGAIN RESULTING IN VERY LOW CONFIDENCE IN VSBY FCST. WILL STICK WITH GOING VSBY TRENDS THIS PERIOD UNTIL HAVE HIGHER CONFIDENCE IN A SOLUTION. A COLD FRONT WILL SWEEP ACROSS THE AREA EARLY SATURDAY. WHILE NOTABLE DRYING OCCURS ALOFT...APPEARS WE MAY STICK FOR SEVERAL HOURS WITH SOME POST FRONTAL STRATUS...AT LEAST UNTIL SATURDAY AFTERNOON WHEN IT MAY FINALLY SCATTER OUT. VSBY SHOULD SHARPLY IMPROVE BEHIND THE FRONT THOUGH WITH WINDS TURNING WESTERLY AND BECOMING INCREASINGLY GUSTY. BMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * VERY LOW CONFIDENCE IN VSBY TRENDS TODAY AND TONIGHT. * HIGH CONFIDENCE IN IFR OR LOWER CIGS THROUGH THE OVERNIGHT HOURS. * HIGH CONFIDENCE IN RAIN TIMING. * MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...MEDIUM CONFIDENCE IN WIND SPEED. BMD //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT...VFR PROBABLE. SUNDAY...STRONG SOUTH WINDS...LLWS POSSIBLE AFTERNOON/EARLY EVENING. VFR PROBABLE. MONDAY...VFR. TUESDAY...CHANCE OF SNOW/IFR. WEDNESDAY AND THURSDAY...VFR PROBABLE. IZZI && .MARINE... 209 PM CST LARGE DOME OF HIGH PRESSURE OVER THE EASTERN SEABOARD HAS DRIFTED EAST...AND STRETCHES FROM CENTRAL QUEBEC SOUTH THROUGH THE CAROLINA COAST. MEANWHILE ACROSS THE CENTRAL PLAINS A SERIES OF LOW PRESSURES EXISTED...WITH ONE ACROSS THE NORTHERN PLAINS AND THE SECOND ACROSS THE CENTRAL PLAINS. THESE TWO AREAS OF LOW PRESSURES WILL CONVERGE UPON LAKE MICHIGAN...CONSOLIDATING INTO A SLIGHTLY STRONGER LOW PRESSURE OVER THE NORTHERN PORTION OF LAKE MICHIGAN EARLY SATURDAY MORNING. WINDS FOR MUCH OF THE LAKE WILL REMAIN SOUTHERLY...WITH THE FAR NORTHERN PORTIONS NEAR THE STRAITS OF MACKINAW BEING SLIGHTLY SOUTHEAST/EAST. THEN WITH THE LOW PASSAGE EXPECTED TO OCCUR SATURDAY MORNING WITH A TRAILING FRONTAL BOUNDARY SLIDING EAST ACROSS THE LAKE...THE GRADIENT IS EXPECTED TO TIGHTEN. FOR THE CENTRAL/SOUTHERN PORTIONS WINDS WILL INCREASE TO NEAR 30 KT BY MIDDAY/EARLY AFTN SAT. THEN AS THE FRONTAL BOUNDARY CONTINUES TO PRESS EAST...WINDS WILL TURN MORE TO THE WEST. FOR THE NORTHERN HALF OF THE LAKE WINDS FOR A PERIOD WILL BECOME NORTHWEST...BEFORE RELAXING TO THE WEST SAT LATE AFTN. HIGH PRESSURE ACROSS THE SOUTHERN PLAINS SAT AFTN WILL CONTINUE TO SLIDE EAST...STRETCHING AN INFLUENCE NORTH TO LAKE MICHIGAN SATURDAY NIGHT/EARLY SUN. THIS COUPLED WITH YET ANOTHER LOW PRESSURE SYSTEM BEGINNING TO PUSH INTO CENTRAL CANADA...WILL ALLOW THE GRADIENT TO TIGHTEN. WINDS SHOULD REMAIN BREEZY SUN AFTN/EVE. THE GRADIENT HAS BECOME SLIGHTLY TIGHTER...ALONG WITH THE LOW PRESSURE BECOME DEEPER TO 28.9 INCHES JUST NORTH OF LAKE SUPERIOR SUN EVE. THIS WILL LIKELY CREATE A PERIOD OF GALES FOR THE LAKE DURING THE SUN AFTN/EVE TIMEFRAME. THE GRADIENT THEN BEGINS TO SLACKEN OFF FOR THE MIDDLE OF NEXT WEEK...WITH JUST A COUPLE WEAK WAVES TRAVERSING THE WESTERN GREAT LAKES REGION. IN THE LONGER RANGE PERIODS FORECAST GUIDANCE IS BEGINNING TO INDICATE A STRENGTHENING LOW PRESSURE OVER THE OHIO VALLEY TUE NIGHT...WHICH COULD RESULT IN A TIGHTENING GRADIENT FOR LAKE MICHIGAN WED AND BREEZY CONDITIONS RETURNING. BEACHLER && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
200 PM CST FRI JAN 10 2014 .DISCUSSION... 1114 AM CST HAVE SPENT THE MORNING EXAMINING THE POTENTIAL FOR DENSE FOG AND THE POSSIBLE NEED FOR AN ADVISORY LATER TODAY...THE APPROACHING THUNDERSTORMS IN WEST CENTRAL ILLINOIS...AND THE FLOOD POTENTIAL GIVEN THE EXPECTED RAINFALL AND WARMING TEMPERATURES. FOR THE NEAR TERM WE ELECTED TO CANCEL THE FREEZING FOG ADVISORY A LITTLE EARLY AS TEMPERATURES IN MOST LOCATIONS HAVE RISEN ABOVE OR VERY NEAR FREEZING. THE NEXT QUESTION WOULD BE WHETHER DENSE FOG DEVELOPS IN THE SATURATED SURFACE LAYER MOVING IN OVER THE SNOWPACK WITH INCREASING DEWPOINTS. OBSERVATIONS JUST UPSTREAM OF THE AREA ARE SHOWING VSBYS AT WORST AROUND 1 MILE...BUT FARTHER UPSTREAM TOWARD THE APPROACHING LOW CENTER THEY ARE MORE COMMONLY AROUND 1/4 TO 1/2 MILE. SO FOR THE AFTERNOON AM NOT ANTICIPATING THE NEED FOR FOG HEADLINES...BUT WILL REEVALUATE LATER TODAY IN CASE SOMETHING MAY BE NEEDED THIS EVENING OR OVERNIGHT. THE AREA OF THUNDERSTORMS AROUND QUINCY AND SOUTHWEST TOWARD JOPLIN MISSOURI IS WELL CORRELATED WITH AN AREA OF ENHANCED LOW LEVEL MOISTURE FLUX SHOWN IN THE RAP MODEL EAST OF THE APPROACHING LOW PRESSURE CENTER. AS THE AFTERNOON EVOLVES AND THE LOW LIFTS NORTHEAST...THE RAP MODEL INCREASES THE MOISTURE FLUX OVER CENTRAL AND NORTHERN ILLINOIS. AREAS OF STEEPER LAPSE RATES ARE ALSO SEEN IN NAM/GFS SOUNDINGS FOR THE AFTERNOON AND EVENING TIMEFRAME. WILL UPDATE FCST GRIDS TO INTRODUCE A SLIGHT CHANCE OF TSTMS MAINLY FOR THE SOUTHERN HALF OF THE AREA. AS FOR FLOODING POTENTIAL...AM NOT PLANNING ON ANY FLOOD WATCH HEADLINES AT THIS TIME GIVEN SO MANY VARIABLES...INCLUDING LOCATION OF HEAVIER RAIN AMOUNTS...DEGREE TO WHICH THE SNOWPACK WOULD SPONGE UP THE RAIN...EVOLUTION OF DEWPOINT TEMPERATURES...AND THE BEHAVIOR OF ICE ON THE RIVERS AND STREAMS. THE BEST POTENTIAL FOR MAINSTEM FLOODING APPEARS TO BE ALONG THE KANKAKEE WHERE A FLOOD WARNING HAS BEEN ISSUED FOR ANTICIPATED MINOR FLOODING. THIS RIVER ALREADY HAD QUITE A BIT OF WATER IN IT...BUT THE OTHERS HAVE A LITTLE MORE ROOM TO HANDLE THE RUNOFF. LENNING //PREV DISCUSSION... 338 AM CST SHORT TERM...TODAY THROUGH SUNDAY NIGHT TODAY/TONIGHT... MULTIPLE CONCERNS IN THE NEAR TERM TODAY...INCLUDING DENSE FOG...FREEZING DRIZZLE/RAIN AND THEN RAIN AND MELTING SNOW LATER TODAY INTO THIS EVENING. GRADUAL INCREASE IN SURFACE MOISTURE OVER DEEP SNOW PACK HAS RESULTED IN FOG DEVELOPMENT EARLY THIS MORNING...WITH MULTIPLE LOCATIONS AOB 1/2 MILE. FOG HAS BEEN MOST DENSE ALONG/WEST OF A LINE FROM UGN TO VYS. WILL LIKELY NEED A DENSE FOG ADVISORY ADVISORY OR FREEZING FOG ADVISORY FOR MOST IF NOT ALL IF THIS AREA FOR PART OF TODAY UNTIL TEMPERATURES WARM AND STEADIER PRECIP ARRIVES LATER...WITH CONTINUED MOISTURE INCREASE AND SATURATION OF SURFACE LAYER OVER SNOWPACK. WEAK ASCENT EARLY TO MID MORNING IN SOUTHWEST FLOW ALOFT WITH INCOMING SHORTWAVE ENERGY COULD ALSO RESULT IN PATCHY FREEZING DRIZZLE...BEST CHANCE OF SEEING MEASURABLE ZR- IN WESTERN HALF OF CWA...BUT CONFIDENCE IS LOW IN ICE ACCUMULATIONS. TEMPERATURE TRENDS WILL BE KEY TO EXTENT OF PROBLEMS TODAY WITH FREEZING RAIN/DRIZZLE. UNTIL BETTER DEWPOINTS SOUTH OF OH RIVER SURGE NORTHWARD...TEMPERATURES SHOULD VERY SLOWLY CLIMB. GUIDANCE IS ALREADY A BIT TOO LOW ON CURRENT TEMPERATURES...SO THINK THAT ONCE STRONGER MIDLEVEL WAVE/MOIST TRANSPORT ARRIVES EARLY TO MID AFTERNOON...MOST IF NOT ALL AREAS SHOULD BE ABOVE FREEZING AND LIMIT FREEZING RAIN THREAT. BIGGEST CONCERN IS FOR WI BORDER AREAS TO WARM A BIT SLOWER AND THUS SEE A FEW HRS OF FREEZING RAIN BEFORE CHANGING TO PLAIN RAIN. HAVE BETTER CONFIDENCE ROUGHLY SOUTH OF I-90 THAT PLAIN RAIN WILL BE PREDOMINANT P-TYPE. REGARDING RAIN AND SNOWMELT...STOUT MIDLEVEL WAVE AND ASSOCIATED SURFACE LOW TRACKING WEST OF CWA WILL AIM PLUME OF 2-3 SD ABOVE NORMAL/A BIT OVER .75 INCH PWAT/INTO AREA BY THIS EVENING. UNTIL DRYSLOT ARRIVES LATE IN THE EVENING INTO THE OVERNIGHT AND SHUTS OFF STEADY RAIN...THERE COULD BE PERIODS OF MODERATE RAIN. LOCAL WRF GUIDANCE IS MUCH MORE BULLISH ON HOW WARM TEMPERATURES ARE THIS EVENING/MID 40S FOR SOUTHEASTERN HALF OF CWA/WITH HEAVIEST RAINFALL. IF TEMPERATURES ARE WARMER THAN UPPER 30S/LOW 40S/THIS COULD ENABLE MORE RAPID SNOWMELT AND HEIGHTEN FLOODING CONCERNS. DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE ANY FLOOD WATCHES...BUT WILL CONTINUE WITH PREVIOUSLY ISSUED ESF TO HIGHLIGHT FLOODING POTENTIAL...INCLUDING BREAK UP ICE JAMS ON AREA RIVERS. SATURDAY THROUGH SUNDAY NIGHT... LOWERED POPS SATURDAY MORNING...WITH ONLY CHANCE POPS FOR FAR NORTH AS DEFORMATION AXIS OF STRENGTHENING SURFACE AND UPPER SYSTEM OVER THE REGION LOOKS TO AT BEST GRAZE THE FAR NORTH. MORE LIKELY SCENARIO IS FOR DEFORMATION TO IMPACT CENTRAL WISCONSIN. THEREFORE...WHILE THERMAL PROFILES WILL BECOME COLD ENOUGH...AT BEST WOULD ONLY EXPECT LIGHT SNOW AND NO ACCUM IN FAR NORTHERN CWA. COOL ADVECTION THROUGH THE DAY WILL RESULT IN ONLY A FEW DEGREE TEMP CLIMB IN AFTERNOON FROM MORNING LOWS IN LOW-MID 30S. THERE SHOULD BE ENOUGH TIME FOR WET SURFACES TO DRY OFF TO PRECLUDE A BIG THREAT OF ICY SPOTS ON ROAD SURFACES SATURDAY NIGHT AS TEMPERATURES FALL INTO THE TEENS AND 20S. RAPID WARM ADVECTION PATTERN THEN SETS UP ON SUNDAY AS H85 TEMPS WARM BACK UP TO +6 TO +8C. A LOOK AT FORECAST SOUNDINGS INDICATES THAT GLOBAL MODELS MAY BE STRUGGLING WITH LOWER LEVEL THERMAL PROFILES DUE TO TRYING TO RESOLVE EXISTING SNOWPACK. AS A RESULT...925 MB TEMPS ON HIGHER RES NAM OF +6 TO +8C MAY BE THE BETTER ROUTE THAN LOW POSITIVE SINGLE DIGITS. ASSUMING THAT MOST OF THE AREA STILL HAS AT LEAST 1 INCH OF SNOW ON THE GROUND...WARMING POTENTIAL WILL BE LESS THAN WITHOUT SNOW. HOWEVER...SOUTHERN EDGE OF SNOWPACK WILL LIKELY BE QUICKLY ERODING...WITH MID 40S IF NOT WARMER POSSIBLE IN SOUTHERN CWA. ONLY AREAS LIMITED TO THE UPPER 30S MAY BE THE FAR NORTHWEST. A COLD FRONT TRAILING FROM CLIPPER SYSTEM OVER NORTHERN LAKES WILL THEN SWING THROUGH CWA SUNDAY NIGHT LIKELY DRY EXCEPT PERHAPS FAR NORTH WHERE SLIGHT POPS WERE MAINTAINED. LONG TERM...MONDAY THROUGH THURSDAY... OVERALL UPPER PATTERN WILL REALIGN TO A RIDGE IN THE WEST/TROUGH IN THE EAST...WHICH IS KNOWN AS A POSITIVE PNA PATTERN. THIS IS TYPICALLY A COLDER BUT FAIRLY DRY SET-UP FOR THE LOCAL AREA. WILL NEED TO WATCH FOR CLIPPER TYPE SYSTEMS IN NORTHWEST FLOW ALOFT. GUIDANCE BECOMES SPLIT ON WHETHER TO FOCUS MORE ENERGY IN SOUTHERN STREAM SYSTEM OR NORTHERN VORT ON MONDAY NIGHT INTO TUESDAY. IN PARTICULAR...ECMWF IS OF MOST INTEREST WITH ITS STRONGER SOUTHERN STREAM WAVE. IF A QUICKER PHASE OCCURS WITH NORTHERN BRANCH FEATURE...MORE THAN SOUTHEAST CWA COULD BE IMPACTED BY A SYSTEM IN THIS TIMEFRAME. OPERATIONAL GFS DOES NOT SEEM TO HAVE MUCH ENSEMBLE SUPPORT WITH ITS UNUSUALLY STRONG CLIPPER SYSTEM TRACKING ACROSS THE AREA ON MONDAY NIGHT. HAVE SLIGHT TO LOW POPS MONDAY NIGHT INTO TUESDAY...WITH THE POSSIBILITY THEN OF MORE CLIPPER ACITIVITY LATER NEXT WEEK. IN BETWEEN LOOKS TO BE PRIMARILY DRY...WITH LAKE EFFECT SNOW FOCUSED EAST OF FAR EASTERN CWA. THE CORE OF THE COLDEST AIR DURING THIS TIME WILL REMAIN NORTH OF US WITH POLAR VORTEX OVER HUDSON BAY...BUT OTHER THAN A BRIEF WARM-UP ON THURSDAY...TEMPERATURES ARE LIKELY TO AVERAGE BELOW NORMAL THROUGH EXTENDED AND BEYOND. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LOW CEILINGS CONTINUING THROUGH THE REST OF THE DAY...IMPROVING BEHIND COLD FRONT EARLY TOMORROW. * VSBY GENERALLY 1-3SM...BUT POSSIBLY LESS THAN A QUARTER MILE IF DENSE FOG WERE TO DEVELOP. BMD //DISCUSSION...UPDATED 18Z... A WASHED OUT WARM FRONT IS LIFTING INTO ILLINOIS EARLY THIS AFTERNOON...WITH A BROAD DEWPOINT GRADIENT SPREADING NORTHWARD ACROSS THE STATE. NORTH OF THE FRONT...CIGS ARE GENERALLY BETWEEN 002 AND 005 WHILE VSBY IS MORE VARIABLE...BUT NUMEROUS 1-3SM REPORTS ARE NOTED ACROSS FAR NORTHERN ILLINOIS DUE TO FOG/MIST. AS LOW PRESSURE TRACKS FROM EASTERN NEBRASKA THIS AFTERNOON INTO SOUTHERN WISCONSIN LATER THIS EVENING...EXPECT NORTHWARD MOISTURE TRANSPORT TO CONTINUE WITH DEWPOINTS RISING INTO THE MID OR UPPER 30S OVER THE SNOWPACK. THE IMMEDIATE CONCERN HERE IS FOR THE POTENTIAL OF DENSE FOG DEVELOPING...WITH MET GUIDANCE INDICATING VSBY TANKING THIS AFTERNOON. FEEL GUIDANCE MAY BE HITTING THIS TOO HARD THOUGH GIVEN THE BROAD TD GRADIENT...AND WILL LEAN TOWARDS A MORE OPTIMISTIC VSBY FORECAST...ADMITTEDLY WITH LOW CONFIDENCE CONSIDERING THE MORE WIDESPREAD 1/4 TO 1/2 SM VSBY IMMEDIATELY AHEAD OF THE LOW. SHOWERS WILL OVERSPREAD THE AREA THIS AFTERNOON AS A POTENT UPPER WAVE LIFTS ACROSS THE REGION. MID LEVEL LAPSE RATES MAY BE SUFFICIENTLY STEEP ENOUGH TO SUPPORT EMBEDDED THUNDERSTORMS AS FAR NORTH AS THE CHICAGO TERMINALS...HOWEVER FELL BEST CHANCES FOR FOR THUNDER WILL STAY SOUTH OF THE I-80 CORRIDOR. RAIN IS EXPECTED TO BE MODERATE WITH BRIEFLY HEAVY SHOWERS POSSIBLE. DEEPER MOISTURE WILL PUSH OUT OF THE AREA MID TO LATE THIS EVENING WITH LINGERING DRIZZLE POSSIBLE INTO THE EARLY OVERNIGHT HOURS. FEEL THAT ONCE THE RAIN STOPS THIS EVENING...THIS WILL BE THE PERIOD THAT MAY HAVE TO BE MONITORED MOST CLOSELY FOR FOG DEVELOPING. DEWPOINTS SHOULD BE CLIMBING INTO THE 35-37 RANGE BY THIS POINT WHICH ASSUMING THERE IS STILL SOME SNOW ON THE GROUND WOULD BE FAVORABLE FOR FOG TO INCREASE IN THICKNESS. UNFORTUNATELY...MET/MAV GUIDANCE SHOWS THE OPPOSITE...WITH IMPROVING VSBY TRENDS AFTER THE RAIN DEPARTS OVERNIGHT...ONCE AGAIN RESULTING IN VERY LOW CONFIDENCE IN VSBY FCST. WILL STICK WITH GOING VSBY TRENDS THIS PERIOD UNTIL HAVE HIGHER CONFIDENCE IN A SOLUTION. A COLD FRONT WILL SWEEP ACROSS THE AREA EARLY SATURDAY. WHILE NOTABLE DRYING OCCURS ALOFT...APPEARS WE MAY STICK FOR SEVERAL HOURS WITH SOME POST FRONTAL STRATUS...AT LEAST UNTIL SATURDAY AFTERNOON WHEN IT MAY FINALLY SCATTER OUT. VSBY SHOULD SHARPLY IMPROVE BEHIND THE FRONT THOUGH WITH WINDS TURNING WESTERLY AND BECOMING INCREASINGLY GUSTY. BMD //ORD AND MDW CONFIDENCE...UPDATED 20Z... * VERY LOW CONFIDENCE IN VSBY TRENDS TODAY AND TONIGHT. * HIGH CONFIDENCE IN IFR OR LOWER CIGS THROUGH THE OVERNIGHT HOURS. * HIGH CONFIDENCE IN RAIN TIMING. * MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...MEDIUM CONFIDENCE IN WIND SPEED. BMD //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT...VFR PROBABLE. SUNDAY...STRONG SOUTH WINDS...LLWS POSSIBLE AFTERNOON/EARLY EVENING. VFR PROBABLE. MONDAY...VFR. TUESDAY...CHANCE OF SNOW/IFR. WEDNESDAY AND THURSDAY...VFR PROBABLE. IZZI && .MARINE... 417 AM CST SOUTH WINDS WILL RAMP UP TODAY IN ADVANCE OF DEVELOPING LOW PRESSURE OVER THE CORNBELT THIS AFTERNOON. THIS LOW WILL TRACK ACROSS NORTHERN LM LATE TONIGHT/EARLY SAT AM ON ITS WAY TO QUEBEC BY SUNDAY. WEAK RIDGE TRAVERSES THE LAKE SAT NIGHT BEFORE A VERY STRONG LOW RACES EAST ACROSS SOUTHERN CANADA SUNDAY RESULTING IN WHAT LOOKS TO BE A PRETTY GOOD SHOT OF SOUTH GALES SUNDAY INTO SUNDAY EVENING. MODELS STRONGLY DIVERGE ON STRENGTH AND TIMING OF NORTHWEST FLOW DISTURBANCES IN THE TUES/WED TIME RANGE RESULTING IN LOW CONFIDENCE FORECAST. IZZI && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1201 PM CST FRI JAN 10 2014 .DISCUSSION... 1114 AM CST HAVE SPENT THE MORNING EXAMINING THE POTENTIAL FOR DENSE FOG AND THE POSSIBLE NEED FOR AN ADVISORY LATER TODAY...THE APPROACHING THUNDERSTORMS IN WEST CENTRAL ILLINOIS...AND THE FLOOD POTENTIAL GIVEN THE EXPECTED RAINFALL AND WARMING TEMPERATURES. FOR THE NEAR TERM WE ELECTED TO CANCEL THE FREEZING FOG ADVISORY A LITTLE EARLY AS TEMPERATURES IN MOST LOCATIONS HAVE RISEN ABOVE OR VERY NEAR FREEZING. THE NEXT QUESTION WOULD BE WHETHER DENSE FOG DEVELOPS IN THE SATURATED SURFACE LAYER MOVING IN OVER THE SNOWPACK WITH INCREASING DEWPOINTS. OBSERVATIONS JUST UPSTREAM OF THE AREA ARE SHOWING VSBYS AT WORST AROUND 1 MILE...BUT FARTHER UPSTREAM TOWARD THE APPROACHING LOW CENTER THEY ARE MORE COMMONLY AROUND 1/4 TO 1/2 MILE. SO FOR THE AFTERNOON AM NOT ANTICIPATING THE NEED FOR FOG HEADLINES...BUT WILL REEVALUATE LATER TODAY IN CASE SOMETHING MAY BE NEEDED THIS EVENING OR OVERNIGHT. THE AREA OF THUNDERSTORMS AROUND QUINCY AND SOUTHWEST TOWARD JOPLIN MISSOURI IS WELL CORRELATED WITH AN AREA OF ENHANCED LOW LEVEL MOISTURE FLUX SHOWN IN THE RAP MODEL EAST OF THE APPROACHING LOW PRESSURE CENTER. AS THE AFTERNOON EVOLVES AND THE LOW LIFTS NORTHEAST...THE RAP MODEL INCREASES THE MOISTURE FLUX OVER CENTRAL AND NORTHERN ILLINOIS. AREAS OF STEEPER LAPSE RATES ARE ALSO SEEN IN NAM/GFS SOUNDINGS FOR THE AFTERNOON AND EVENING TIMEFRAME. WILL UPDATE FCST GRIDS TO INTRODUCE A SLIGHT CHANCE OF TSTMS MAINLY FOR THE SOUTHERN HALF OF THE AREA. AS FOR FLOODING POTENTIAL...AM NOT PLANNING ON ANY FLOOD WATCH HEADLINES AT THIS TIME GIVEN SO MANY VARIABLES...INCLUDING LOCATION OF HEAVIER RAIN AMOUNTS...DEGREE TO WHICH THE SNOWPACK WOULD SPONGE UP THE RAIN...EVOLUTION OF DEWPOINT TEMPERATURES...AND THE BEHAVIOR OF ICE ON THE RIVERS AND STREAMS. THE BEST POTENTIAL FOR MAINSTEM FLOODING APPEARS TO BE ALONG THE KANKAKEE WHERE A FLOOD WARNING HAS BEEN ISSUED FOR ANTICIPATED MINOR FLOODING. THIS RIVER ALREADY HAD QUITE A BIT OF WATER IN IT...BUT THE OTHERS HAVE A LITTLE MORE ROOM TO HANDLE THE RUNOFF. LENNING //PREV DISCUSSION... 338 AM CST SHORT TERM...TODAY THROUGH SUNDAY NIGHT TODAY/TONIGHT... MULTIPLE CONCERNS IN THE NEAR TERM TODAY...INCLUDING DENSE FOG...FREEZING DRIZZLE/RAIN AND THEN RAIN AND MELTING SNOW LATER TODAY INTO THIS EVENING. GRADUAL INCREASE IN SURFACE MOISTURE OVER DEEP SNOW PACK HAS RESULTED IN FOG DEVELOPMENT EARLY THIS MORNING...WITH MULTIPLE LOCATIONS AOB 1/2 MILE. FOG HAS BEEN MOST DENSE ALONG/WEST OF A LINE FROM UGN TO VYS. WILL LIKELY NEED A DENSE FOG ADVISORY ADVISORY OR FREEZING FOG ADVISORY FOR MOST IF NOT ALL IF THIS AREA FOR PART OF TODAY UNTIL TEMPERATURES WARM AND STEADIER PRECIP ARRIVES LATER...WITH CONTINUED MOISTURE INCREASE AND SATURATION OF SURFACE LAYER OVER SNOWPACK. WEAK ASCENT EARLY TO MID MORNING IN SOUTHWEST FLOW ALOFT WITH INCOMING SHORTWAVE ENERGY COULD ALSO RESULT IN PATCHY FREEZING DRIZZLE...BEST CHANCE OF SEEING MEASURABLE ZR- IN WESTERN HALF OF CWA...BUT CONFIDENCE IS LOW IN ICE ACCUMULATIONS. TEMPERATURE TRENDS WILL BE KEY TO EXTENT OF PROBLEMS TODAY WITH FREEZING RAIN/DRIZZLE. UNTIL BETTER DEWPOINTS SOUTH OF OH RIVER SURGE NORTHWARD...TEMPERATURES SHOULD VERY SLOWLY CLIMB. GUIDANCE IS ALREADY A BIT TOO LOW ON CURRENT TEMPERATURES...SO THINK THAT ONCE STRONGER MIDLEVEL WAVE/MOIST TRANSPORT ARRIVES EARLY TO MID AFTERNOON...MOST IF NOT ALL AREAS SHOULD BE ABOVE FREEZING AND LIMIT FREEZING RAIN THREAT. BIGGEST CONCERN IS FOR WI BORDER AREAS TO WARM A BIT SLOWER AND THUS SEE A FEW HRS OF FREEZING RAIN BEFORE CHANGING TO PLAIN RAIN. HAVE BETTER CONFIDENCE ROUGHLY SOUTH OF I-90 THAT PLAIN RAIN WILL BE PREDOMINANT P-TYPE. REGARDING RAIN AND SNOWMELT...STOUT MIDLEVEL WAVE AND ASSOCIATED SURFACE LOW TRACKING WEST OF CWA WILL AIM PLUME OF 2-3 SD ABOVE NORMAL/A BIT OVER .75 INCH PWAT/INTO AREA BY THIS EVENING. UNTIL DRYSLOT ARRIVES LATE IN THE EVENING INTO THE OVERNIGHT AND SHUTS OFF STEADY RAIN...THERE COULD BE PERIODS OF MODERATE RAIN. LOCAL WRF GUIDANCE IS MUCH MORE BULLISH ON HOW WARM TEMPERATURES ARE THIS EVENING/MID 40S FOR SOUTHEASTERN HALF OF CWA/WITH HEAVIEST RAINFALL. IF TEMPERATURES ARE WARMER THAN UPPER 30S/LOW 40S/THIS COULD ENABLE MORE RAPID SNOWMELT AND HEIGHTEN FLOODING CONCERNS. DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE ANY FLOOD WATCHES...BUT WILL CONTINUE WITH PREVIOUSLY ISSUED ESF TO HIGHLIGHT FLOODING POTENTIAL...INCLUDING BREAK UP ICE JAMS ON AREA RIVERS. SATURDAY THROUGH SUNDAY NIGHT... LOWERED POPS SATURDAY MORNING...WITH ONLY CHANCE POPS FOR FAR NORTH AS DEFORMATION AXIS OF STRENGTHENING SURFACE AND UPPER SYSTEM OVER THE REGION LOOKS TO AT BEST GRAZE THE FAR NORTH. MORE LIKELY SCENARIO IS FOR DEFORMATION TO IMPACT CENTRAL WISCONSIN. THEREFORE...WHILE THERMAL PROFILES WILL BECOME COLD ENOUGH...AT BEST WOULD ONLY EXPECT LIGHT SNOW AND NO ACCUM IN FAR NORTHERN CWA. COOL ADVECTION THROUGH THE DAY WILL RESULT IN ONLY A FEW DEGREE TEMP CLIMB IN AFTERNOON FROM MORNING LOWS IN LOW-MID 30S. THERE SHOULD BE ENOUGH TIME FOR WET SURFACES TO DRY OFF TO PRECLUDE A BIG THREAT OF ICY SPOTS ON ROAD SURFACES SATURDAY NIGHT AS TEMPERATURES FALL INTO THE TEENS AND 20S. RAPID WARM ADVECTION PATTERN THEN SETS UP ON SUNDAY AS H85 TEMPS WARM BACK UP TO +6 TO +8C. A LOOK AT FORECAST SOUNDINGS INDICATES THAT GLOBAL MODELS MAY BE STRUGGLING WITH LOWER LEVEL THERMAL PROFILES DUE TO TRYING TO RESOLVE EXISTING SNOWPACK. AS A RESULT...925 MB TEMPS ON HIGHER RES NAM OF +6 TO +8C MAY BE THE BETTER ROUTE THAN LOW POSITIVE SINGLE DIGITS. ASSUMING THAT MOST OF THE AREA STILL HAS AT LEAST 1 INCH OF SNOW ON THE GROUND...WARMING POTENTIAL WILL BE LESS THAN WITHOUT SNOW. HOWEVER...SOUTHERN EDGE OF SNOWPACK WILL LIKELY BE QUICKLY ERODING...WITH MID 40S IF NOT WARMER POSSIBLE IN SOUTHERN CWA. ONLY AREAS LIMITED TO THE UPPER 30S MAY BE THE FAR NORTHWEST. A COLD FRONT TRAILING FROM CLIPPER SYSTEM OVER NORTHERN LAKES WILL THEN SWING THROUGH CWA SUNDAY NIGHT LIKELY DRY EXCEPT PERHAPS FAR NORTH WHERE SLIGHT POPS WERE MAINTAINED. LONG TERM...MONDAY THROUGH THURSDAY... OVERALL UPPER PATTERN WILL REALIGN TO A RIDGE IN THE WEST/TROUGH IN THE EAST...WHICH IS KNOWN AS A POSITIVE PNA PATTERN. THIS IS TYPICALLY A COLDER BUT FAIRLY DRY SET-UP FOR THE LOCAL AREA. WILL NEED TO WATCH FOR CLIPPER TYPE SYSTEMS IN NORTHWEST FLOW ALOFT. GUIDANCE BECOMES SPLIT ON WHETHER TO FOCUS MORE ENERGY IN SOUTHERN STREAM SYSTEM OR NORTHERN VORT ON MONDAY NIGHT INTO TUESDAY. IN PARTICULAR...ECMWF IS OF MOST INTEREST WITH ITS STRONGER SOUTHERN STREAM WAVE. IF A QUICKER PHASE OCCURS WITH NORTHERN BRANCH FEATURE...MORE THAN SOUTHEAST CWA COULD BE IMPACTED BY A SYSTEM IN THIS TIMEFRAME. OPERATIONAL GFS DOES NOT SEEM TO HAVE MUCH ENSEMBLE SUPPORT WITH ITS UNUSUALLY STRONG CLIPPER SYSTEM TRACKING ACROSS THE AREA ON MONDAY NIGHT. HAVE SLIGHT TO LOW POPS MONDAY NIGHT INTO TUESDAY...WITH THE POSSIBILITY THEN OF MORE CLIPPER ACITIVITY LATER NEXT WEEK. IN BETWEEN LOOKS TO BE PRIMARILY DRY...WITH LAKE EFFECT SNOW FOCUSED EAST OF FAR EASTERN CWA. THE CORE OF THE COLDEST AIR DURING THIS TIME WILL REMAIN NORTH OF US WITH POLAR VORTEX OVER HUDSON BAY...BUT OTHER THAN A BRIEF WARM-UP ON THURSDAY...TEMPERATURES ARE LIKELY TO AVERAGE BELOW NORMAL THROUGH EXTENDED AND BEYOND. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * LOW CEILINGS CONTINUING THROUGH THE REST OF THE DAY...IMPROVING BEHIND COLD FRONT EARLY TOMORROW. * VSBY GENERALLY 1-3SM...BUT POSSIBLY LESS THAN A QUARTER MILE IF DENSE FOG WERE TO DEVELOP. BMD //DISCUSSION...UPDATED 18Z... A WASHED OUT WARM FRONT IS LIFTING INTO ILLINOIS EARLY THIS AFTERNOON...WITH A BROAD DEWPOINT GRADIENT SPREADING NORTHWARD ACROSS THE STATE. NORTH OF THE FRONT...CIGS ARE GENERALLY BETWEEN 002 AND 005 WHILE VSBY IS MORE VARIABLE...BUT NUMEROUS 1-3SM REPORTS ARE NOTED ACROSS FAR NORTHERN ILLINOIS DUE TO FOG/MIST. AS LOW PRESSURE TRACKS FROM EASTERN NEBRASKA THIS AFTERNOON INTO SOUTHERN WISCONSIN LATER THIS EVENING...EXPECT NORTHWARD MOISTURE TRANSPORT TO CONTINUE WITH DEWPOINTS RISING INTO THE MID OR UPPER 30S OVER THE SNOWPACK. THE IMMEDIATE CONCERN HERE IS FOR THE POTENTIAL OF DENSE FOG DEVELOPING...WITH MET GUIDANCE INDICATING VSBY TANKING THIS AFTERNOON. FEEL GUIDANCE MAY BE HITTING THIS TOO HARD THOUGH GIVEN THE BROAD TD GRADIENT...AND WILL LEAN TOWARDS A MORE OPTIMISTIC VSBY FORECAST...ADMITTEDLY WITH LOW CONFIDENCE CONSIDERING THE MORE WIDESPREAD 1/4 TO 1/2 SM VSBY IMMEDIATELY AHEAD OF THE LOW. SHOWERS WILL OVERSPREAD THE AREA THIS AFTERNOON AS A POTENT UPPER WAVE LIFTS ACROSS THE REGION. MID LEVEL LAPSE RATES MAY BE SUFFICIENTLY STEEP ENOUGH TO SUPPORT EMBEDDED THUNDERSTORMS AS FAR NORTH AS THE CHICAGO TERMINALS...HOWEVER FELL BEST CHANCES FOR FOR THUNDER WILL STAY SOUTH OF THE I-80 CORRIDOR. RAIN IS EXPECTED TO BE MODERATE WITH BRIEFLY HEAVY SHOWERS POSSIBLE. DEEPER MOISTURE WILL PUSH OUT OF THE AREA MID TO LATE THIS EVENING WITH LINGERING DRIZZLE POSSIBLE INTO THE EARLY OVERNIGHT HOURS. FEEL THAT ONCE THE RAIN STOPS THIS EVENING...THIS WILL BE THE PERIOD THAT MAY HAVE TO BE MONITORED MOST CLOSELY FOR FOG DEVELOPING. DEWPOINTS SHOULD BE CLIMBING INTO THE 35-37 RANGE BY THIS POINT WHICH ASSUMING THERE IS STILL SOME SNOW ON THE GROUND WOULD BE FAVORABLE FOR FOG TO INCREASE IN THICKNESS. UNFORTUNATELY...MET/MAV GUIDANCE SHOWS THE OPPOSITE...WITH IMPROVING VSBY TRENDS AFTER THE RAIN DEPARTS OVERNIGHT...ONCE AGAIN RESULTING IN VERY LOW CONFIDENCE IN VSBY FCST. WILL STICK WITH GOING VSBY TRENDS THIS PERIOD UNTIL HAVE HIGHER CONFIDENCE IN A SOLUTION. A COLD FRONT WILL SWEEP ACROSS THE AREA EARLY SATURDAY. WHILE NOTABLE DRYING OCCURS ALOFT...APPEARS WE MAY STICK FOR SEVERAL HOURS WITH SOME POST FRONTAL STRATUS...AT LEAST UNTIL SATURDAY AFTERNOON WHEN IT MAY FINALLY SCATTER OUT. VSBY SHOULD SHARPLY IMPROVE BEHIND THE FRONT THOUGH WITH WINDS TURNING WESTERLY AND BECOMING INCREASINGLY GUSTY. BMD //ORD AND MDW CONFIDENCE...UPDATED 18Z... * VERY LOW CONFIDENCE IN VSBY TRENDS TODAY AND TONIGHT. * HIGH CONFIDENCE IN IFR OR LOWER CIGS THROUGH THE OVERNIGHT HOURS. * MEDIUM-HIGH CONFIDENCE IN RAIN TIMING. * MEDIUM-HIGH CONFIDENCE IN WIND DIRECTION...MEDIUM CONFIDENCE IN WIND SPEED. BMD //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT...VFR PROBABLE. SUNDAY...STRONG SOUTH WINDS...LLWS POSSIBLE AFTERNOON/EARLY EVENING. VFR PROBABLE. MONDAY...VFR. TUESDAY...CHANCE OF SNOW/IFR. WEDNESDAY AND THURSDAY...VFR PROBABLE. IZZI && .MARINE... 417 AM CST SOUTH WINDS WILL RAMP UP TODAY IN ADVANCE OF DEVELOPING LOW PRESSURE OVER THE CORNBELT THIS AFTERNOON. THIS LOW WILL TRACK ACROSS NORTHERN LM LATE TONIGHT/EARLY SAT AM ON ITS WAY TO QUEBEC BY SUNDAY. WEAK RIDGE TRAVERSES THE LAKE SAT NIGHT BEFORE A VERY STRONG LOW RACES EAST ACROSS SOUTHERN CANADA SUNDAY RESULTING IN WHAT LOOKS TO BE A PRETTY GOOD SHOT OF SOUTH GALES SUNDAY INTO SUNDAY EVENING. MODELS STRONGLY DIVERGE ON STRENGTH AND TIMING OF NORTHWEST FLOW DISTURBANCES IN THE TUES/WED TIME RANGE RESULTING IN LOW CONFIDENCE FORECAST. IZZI && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1140 AM CST FRI JAN 10 2014 .DISCUSSION... 1114 AM CST HAVE SPENT THE MORNING EXAMINING THE POTENTIAL FOR DENSE FOG AND THE POSSIBLE NEED FOR AN ADVISORY LATER TODAY...THE APPROACHING THUNDERSTORMS IN WEST CENTRAL ILLINOIS...AND THE FLOOD POTENTIAL GIVEN THE EXPECTED RAINFALL AND WARMING TEMPERATURES. FOR THE NEAR TERM WE ELECTED TO CANCEL THE FREEZING FOG ADVISORY A LITTLE EARLY AS TEMPERATURES IN MOST LOCATIONS HAVE RISEN ABOVE OR VERY NEAR FREEZING. THE NEXT QUESTION WOULD BE WHETHER DENSE FOG DEVELOPS IN THE SATURATED SURFACE LAYER MOVING IN OVER THE SNOWPACK WITH INCREASING DEWPOINTS. OBSERVATIONS JUST UPSTREAM OF THE AREA ARE SHOWING VSBYS AT WORST AROUND 1 MILE...BUT FARTHER UPSTREAM TOWARD THE APPROACHING LOW CENTER THEY ARE MORE COMMONLY AROUND 1/4 TO 1/2 MILE. SO FOR THE AFTERNOON AM NOT ANTICIPATING THE NEED FOR FOG HEADLINES...BUT WILL REEVALUATE LATER TODAY IN CASE SOMETHING MAY BE NEEDED THIS EVENING OR OVERNIGHT. THE AREA OF THUNDERSTORMS AROUND QUINCY AND SOUTHWEST TOWARD JOPLIN MISSOURI IS WELL CORRELATED WITH AN AREA OF ENHANCED LOW LEVEL MOISTURE FLUX SHOWN IN THE RAP MODEL EAST OF THE APPROACHING LOW PRESSURE CENTER. AS THE AFTERNOON EVOLVES AND THE LOW LIFTS NORTHEAST...THE RAP MODEL INCREASES THE MOISTURE FLUX OVER CENTRAL AND NORTHERN ILLINOIS. AREAS OF STEEPER LAPSE RATES ARE ALSO SEEN IN NAM/GFS SOUNDINGS FOR THE AFTERNOON AND EVENING TIMEFRAME. WILL UPDATE FCST GRIDS TO INTRODUCE A SLIGHT CHANCE OF TSTMS MAINLY FOR THE SOUTHERN HALF OF THE AREA. AS FOR FLOODING POTENTIAL...AM NOT PLANNING ON ANY FLOOD WATCH HEADLINES AT THIS TIME GIVEN SO MANY VARIABLES...INCLUDING LOCATION OF HEAVIER RAIN AMOUNTS...DEGREE TO WHICH THE SNOWPACK WOULD SPONGE UP THE RAIN...EVOLUTION OF DEWPOINT TEMPERATURES...AND THE BEHAVIOR OF ICE ON THE RIVERS AND STREAMS. THE BEST POTENTIAL FOR MAINSTEM FLOODING APPEARS TO BE ALONG THE KANKAKEE WHERE A FLOOD WARNING HAS BEEN ISSUED FOR ANTICIPATED MINOR FLOODING. THIS RIVER ALREADY HAD QUITE A BIT OF WATER IN IT...BUT THE OTHERS HAVE A LITTLE MORE ROOM TO HANDLE THE RUNOFF. LENNING && .PREV DISCUSSION... 338 AM CST SHORT TERM...TODAY THROUGH SUNDAY NIGHT TODAY/TONIGHT... MULTIPLE CONCERNS IN THE NEAR TERM TODAY...INCLUDING DENSE FOG...FREEZING DRIZZLE/RAIN AND THEN RAIN AND MELTING SNOW LATER TODAY INTO THIS EVENING. GRADUAL INCREASE IN SURFACE MOISTURE OVER DEEP SNOW PACK HAS RESULTED IN FOG DEVELOPMENT EARLY THIS MORNING...WITH MULTIPLE LOCATIONS AOB 1/2 MILE. FOG HAS BEEN MOST DENSE ALONG/WEST OF A LINE FROM UGN TO VYS. WILL LIKELY NEED A DENSE FOG ADVISORY ADVISORY OR FREEZING FOG ADVISORY FOR MOST IF NOT ALL IF THIS AREA FOR PART OF TODAY UNTIL TEMPERATURES WARM AND STEADIER PRECIP ARRIVES LATER...WITH CONTINUED MOISTURE INCREASE AND SATURATION OF SURFACE LAYER OVER SNOWPACK. WEAK ASCENT EARLY TO MID MORNING IN SOUTHWEST FLOW ALOFT WITH INCOMING SHORTWAVE ENERGY COULD ALSO RESULT IN PATCHY FREEZING DRIZZLE...BEST CHANCE OF SEEING MEASURABLE ZR- IN WESTERN HALF OF CWA...BUT CONFIDENCE IS LOW IN ICE ACCUMULATIONS. TEMPERATURE TRENDS WILL BE KEY TO EXTENT OF PROBLEMS TODAY WITH FREEZING RAIN/DRIZZLE. UNTIL BETTER DEWPOINTS SOUTH OF OH RIVER SURGE NORTHWARD...TEMPERATURES SHOULD VERY SLOWLY CLIMB. GUIDANCE IS ALREADY A BIT TOO LOW ON CURRENT TEMPERATURES...SO THINK THAT ONCE STRONGER MIDLEVEL WAVE/MOIST TRANSPORT ARRIVES EARLY TO MID AFTERNOON...MOST IF NOT ALL AREAS SHOULD BE ABOVE FREEZING AND LIMIT FREEZING RAIN THREAT. BIGGEST CONCERN IS FOR WI BORDER AREAS TO WARM A BIT SLOWER AND THUS SEE A FEW HRS OF FREEZING RAIN BEFORE CHANGING TO PLAIN RAIN. HAVE BETTER CONFIDENCE ROUGHLY SOUTH OF I-90 THAT PLAIN RAIN WILL BE PREDOMINANT P-TYPE. REGARDING RAIN AND SNOWMELT...STOUT MIDLEVEL WAVE AND ASSOCIATED SURFACE LOW TRACKING WEST OF CWA WILL AIM PLUME OF 2-3 SD ABOVE NORMAL/A BIT OVER .75 INCH PWAT/INTO AREA BY THIS EVENING. UNTIL DRYSLOT ARRIVES LATE IN THE EVENING INTO THE OVERNIGHT AND SHUTS OFF STEADY RAIN...THERE COULD BE PERIODS OF MODERATE RAIN. LOCAL WRF GUIDANCE IS MUCH MORE BULLISH ON HOW WARM TEMPERATURES ARE THIS EVENING/MID 40S FOR SOUTHEASTERN HALF OF CWA/WITH HEAVIEST RAINFALL. IF TEMPERATURES ARE WARMER THAN UPPER 30S/LOW 40S/THIS COULD ENABLE MORE RAPID SNOWMELT AND HEIGHTEN FLOODING CONCERNS. DO NOT HAVE ENOUGH CONFIDENCE TO ISSUE ANY FLOOD WATCHES...BUT WILL CONTINUE WITH PREVIOUSLY ISSUED ESF TO HIGHLIGHT FLOODING POTENTIAL...INCLUDING BREAK UP ICE JAMS ON AREA RIVERS. SATURDAY THROUGH SUNDAY NIGHT... LOWERED POPS SATURDAY MORNING...WITH ONLY CHANCE POPS FOR FAR NORTH AS DEFORMATION AXIS OF STRENGTHENING SURFACE AND UPPER SYSTEM OVER THE REGION LOOKS TO AT BEST GRAZE THE FAR NORTH. MORE LIKELY SCENARIO IS FOR DEFORMATION TO IMPACT CENTRAL WISCONSIN. THEREFORE...WHILE THERMAL PROFILES WILL BECOME COLD ENOUGH...AT BEST WOULD ONLY EXPECT LIGHT SNOW AND NO ACCUM IN FAR NORTHERN CWA. COOL ADVECTION THROUGH THE DAY WILL RESULT IN ONLY A FEW DEGREE TEMP CLIMB IN AFTERNOON FROM MORNING LOWS IN LOW-MID 30S. THERE SHOULD BE ENOUGH TIME FOR WET SURFACES TO DRY OFF TO PRECLUDE A BIG THREAT OF ICY SPOTS ON ROAD SURFACES SATURDAY NIGHT AS TEMPERATURES FALL INTO THE TEENS AND 20S. RAPID WARM ADVECTION PATTERN THEN SETS UP ON SUNDAY AS H85 TEMPS WARM BACK UP TO +6 TO +8C. A LOOK AT FORECAST SOUNDINGS INDICATES THAT GLOBAL MODELS MAY BE STRUGGLING WITH LOWER LEVEL THERMAL PROFILES DUE TO TRYING TO RESOLVE EXISTING SNOWPACK. AS A RESULT...925 MB TEMPS ON HIGHER RES NAM OF +6 TO +8C MAY BE THE BETTER ROUTE THAN LOW POSITIVE SINGLE DIGITS. ASSUMING THAT MOST OF THE AREA STILL HAS AT LEAST 1 INCH OF SNOW ON THE GROUND...WARMING POTENTIAL WILL BE LESS THAN WITHOUT SNOW. HOWEVER...SOUTHERN EDGE OF SNOWPACK WILL LIKELY BE QUICKLY ERODING...WITH MID 40S IF NOT WARMER POSSIBLE IN SOUTHERN CWA. ONLY AREAS LIMITED TO THE UPPER 30S MAY BE THE FAR NORTHWEST. A COLD FRONT TRAILING FROM CLIPPER SYSTEM OVER NORTHERN LAKES WILL THEN SWING THROUGH CWA SUNDAY NIGHT LIKELY DRY EXCEPT PERHAPS FAR NORTH WHERE SLIGHT POPS WERE MAINTAINED. LONG TERM...MONDAY THROUGH THURSDAY... OVERALL UPPER PATTERN WILL REALIGN TO A RIDGE IN THE WEST/TROUGH IN THE EAST...WHICH IS KNOWN AS A POSITIVE PNA PATTERN. THIS IS TYPICALLY A COLDER BUT FAIRLY DRY SET-UP FOR THE LOCAL AREA. WILL NEED TO WATCH FOR CLIPPER TYPE SYSTEMS IN NORTHWEST FLOW ALOFT. GUIDANCE BECOMES SPLIT ON WHETHER TO FOCUS MORE ENERGY IN SOUTHERN STREAM SYSTEM OR NORTHERN VORT ON MONDAY NIGHT INTO TUESDAY. IN PARTICULAR...ECMWF IS OF MOST INTEREST WITH ITS STRONGER SOUTHERN STREAM WAVE. IF A QUICKER PHASE OCCURS WITH NORTHERN BRANCH FEATURE...MORE THAN SOUTHEAST CWA COULD BE IMPACTED BY A SYSTEM IN THIS TIMEFRAME. OPERATIONAL GFS DOES NOT SEEM TO HAVE MUCH ENSEMBLE SUPPORT WITH ITS UNUSUALLY STRONG CLIPPER SYSTEM TRACKING ACROSS THE AREA ON MONDAY NIGHT. HAVE SLIGHT TO LOW POPS MONDAY NIGHT INTO TUESDAY...WITH THE POSSIBILITY THEN OF MORE CLIPPER ACITIVITY LATER NEXT WEEK. IN BETWEEN LOOKS TO BE PRIMARILY DRY...WITH LAKE EFFECT SNOW FOCUSED EAST OF FAR EASTERN CWA. THE CORE OF THE COLDEST AIR DURING THIS TIME WILL REMAIN NORTH OF US WITH POLAR VORTEX OVER HUDSON BAY...BUT OTHER THAN A BRIEF WARM-UP ON THURSDAY...TEMPERATURES ARE LIKELY TO AVERAGE BELOW NORMAL THROUGH EXTENDED AND BEYOND. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * LIFR CONDITIONS GENERALLY EXPECTED TO PERSIST TODAY * DENSE FOG POSSIBLE THIS AFTERNOON AND EVENING. * RAIN DEVELOPS LATE THIS AFTERNOON AND CONTINUES THROUGH MID EVENING...SOME MINOR IMPROVEMENTS TO CIGS/VSBY PSBL WITH THE RAIN IZZI //DISCUSSION...UPDATED 12Z... FAIRLY MOIST AND MILD AIR CONTINUES TO TRY AND STREAM NORTH INTO THE AREA OVER THE DENSE COLD SNOW COVER RESULTING IN LOW CLOUDS AND FOG. GENERALLY SPEAKING...ALL SIGNS WOULD TEND TO POINT TO CONDITIONS NOT IMPROVING MUCH TODAY AND POSSIBLY DETERIORATING AS HIGHER DEWPOINTS MOVE IN LATER THIS MORNING INTO THE AFTERNOON. HAVE SEEN A FEW SITES POP UP WITH HIGHER CIGS/VSBY RECENTLY AND STRUGGLING TO FIND A GOOD METEOROLOGICAL REASONING FOR THAT SO FOR THE TAFS DECIDED TO TREAT THAT AS A TEMPORARY CONDITIONS RATHER THAN THE BEGINNING OF A TREND...THOUGH NO DOUBT THE CHANCE OF THE DAY SHIFT HAVING TO CHASE TRENDS IS PRETTY HIGH TODAY. STILL MOSTLY ERRING ON THE OPTIMISTIC SIDE TO PERHAPS MIDDLE OF THE ROAD IN THE TAFS...THOUGH FINALLY THREW IN THE TOWEL AND LOWERED MDW AS THEY HAVE BEEN REPORTING VSBY BELOW 1SM FOR HOURS NOW WITHOUT SHOWING ANY SIGNS OF IMPROVEMENT. GUIDANCE WOULD SUGGEST CONDITIONS WORSENING THIS AFTERNOON...THOUGH AM HOLDING OUT SOME HOPE FOR A LITTLE BIT OF IMPROVEMENT WHEN THE STEADIER RAIN ARRIVES TOWARD SUNSET. EXPECT IFR/LIFR TO CONTINUE THROUGH MOST OF TONIGHT AS THE HIGH DEWPOINTS EAT AWAY AT THE SNOW COVER...THOUGH WIND SHIFT TO WEST TOWARD SUNRISE SHOULD BRING IN A BIT DRIER AIR AND OFFER UP A BETTER CHANCE TO RISE ABOVE IFR. IZZI //ORD AND MDW CONFIDENCE...UPDATED 16Z... * LOW CONFIDENCE IN VSBY TRENDS * HIGH CONFIDENCE IN IFR/LIFR CIGS THROUGH TONIGHT * HIGH CONFIDENCE IN TIMING OF ONSET OF STEADIER RAIN +/- AN HOUR OR SO IZZI/BMD //OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z... SATURDAY NIGHT...VFR PROBABLE. SUNDAY...STRONG SOUTH WINDS...LLWS POSSIBLE AFTERNOON/EARLY EVENING. VFR PROBABLE. MONDAY...VFR. TUESDAY...CHANCE OF SNOW/IFR. WEDNESDAY AND THURSDAY...VFR PROBABLE. IZZI && .MARINE... 417 AM CST SOUTH WINDS WILL RAMP UP TODAY IN ADVANCE OF DEVELOPING LOW PRESSURE OVER THE CORNBELT THIS AFTERNOON. THIS LOW WILL TRACK ACROSS NORTHERN LM LATE TONIGHT/EARLY SAT AM ON ITS WAY TO QUEBEC BY SUNDAY. WEAK RIDGE TRAVERSES THE LAKE SAT NIGHT BEFORE A VERY STRONG LOW RACES EAST ACROSS SOUTHERN CANADA SUNDAY RESULTING IN WHAT LOOKS TO BE A PRETTY GOOD SHOT OF SOUTH GALES SUNDAY INTO SUNDAY EVENING. MODELS STRONGLY DIVERGE ON STRENGTH AND TIMING OF NORTHWEST FLOW DISTURBANCES IN THE TUES/WED TIME RANGE RESULTING IN LOW CONFIDENCE FORECAST. IZZI && .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/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1223 PM EST FRI JAN 10 2014 .SYNOPSIS... ISSUED AT 420 AM EST FRI JAN 10 2014 SOME PATCHY DRIZZLE OF FREEZING DRIZZLE CAN BE EXPECTED THIS MORNING AS AN UPPER LEVEL DISTURBANCE SHIFTS EAST OF THE AREA. A STRONGER UPPER LEVEL DISTURBANCE WILL CONTINUE TO TAKE SHAPE ACROSS THE PLAINS TODAY AND WILL TRACK EASTWARD TONIGHT BRINGING WIDESPREAD RAIN TO THE AREA. RAIN WILL TAPER FROM WEST TO EAST LATE TONIGHT INTO EARLY SATURDAY. HIGH TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE MID AND UPPER 30S ACROSS CENTRAL LOWER MICHIGAN TO THE LOWER TO MID 40S FROM CENTRAL INDIANA INTO WEST CENTRAL OHIO. LOW TEMPERATURES TONIGHT WILL DROP INTO THE MID AND UPPER 30S FOR MOST LOCATIONS...WITH LOWER 40S ACROSS WEST CENTRAL OHIO. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 420 AM EST FRI JAN 10 2014 BRIEF LULL IN MEASURABLE PRECIP IS SETTING UP THIS MORNING AS STRONGEST DPVA WITH COMPACT SHORT WAVE HAS SHIFTED INTO NORTHWEST OHIO...AND THIS FORCING WILL QUICKLY TRANSLATE EASTWARD THIS MORNING OUT OF THE FORECAST AREA. REDUCED STATIC STABILITY IN THE MID LEVELS AND STEEP MID/UPPER LEVEL LAPSE RATES HAVE ALLOWED SECONDARY BLOSSOMING OF RADAR RETURNS PAST FEW HOURS ACROSS FAR SOUTHEAST PORTIONS OF THE AREA. HOWEVER...DRIER MID LEVEL AIR IS ALREADY ADVECTING ACROSS THESE LOCATIONS WITH RAP SHORT TERM BUFFER SOUNDINGS INDICATING TRANSITION TO MORE OF A LIGHT FREEZING DRIZZLE PRECIP TYPE. WEAK UPPER LEVEL SHORT WAVE RIDGING/SUBSIDENCE WILL CONTINUE TO BUILD INTO THE AREA FOR A SHORT TERM THIS MORNING WITH ONLY VERY SHALLOW AND WEAK VERTICAL MOTIONS THIS MORNING. SECONDARY LOW LEVEL ISENTROPIC SURGE APPEARS TO BE TAKING SHAPE ACROSS CENTRAL INDIANA WITH SECONDARY WARM FRONT...AND REGIONAL RADAR MOSAIC/SFC OBS HAVE BEEN INDICATING INCREASING -DZ/-FZDZ ACROSS CENTRAL INDIANA. EXPECTING DRIZZLE TO INCREASE IN COVERAGE TOWARD 12Z ACROSS THE AREA WITH NEAR SFC WET BULBS VERY MARGINAL IN TERMS OF SUPPORTING DRIZZLE OR FREEZING DRIZZLE...PARTICULARLY ACROSS THE FAR SOUTH. WILL KEEP -FZDZ MENTION GOING THIS MORNING AND HAVE MAINTAINED NATURE OF PREVIOUS FORECAST IN SOUTH TO NORTH EVOLUTION THROUGH THE MORNING HOURS OF TRANSITION FROM -FZDZ TO -DZ. WITH LOW CONFIDENCE IN EXTENT/INTENSITY OF ANY FZDZ THIS MORNING AND INCREASING MARGINAL LOW LEVEL WET BULB PROFILES WILL HOLD OFF ON ANY HEADLINES AND CONTINUE MENTION IN MORNING HWO. OTHERWISE A MILDER DAY IN STORE ALTHOUGH SOLID SNOWPACK ACROSS THE AREA WILL LIMIT EXTENT OF SFC WARMUP WITH WAA...WITH HIGHS GENERALLY FROM MID 30S TO AROUND 40. FOG ALSO EXPECTED TO BECOME MORE PREVALENT TODAY FROM SOUTHWEST TO NORTHEAST WITH LOW LEVEL MOISTURE ADVECTION OVER SNOWPACK. FOCUS FOR THE REMAINDER OF THE SHORT TERM WILL THEN SHIFT TO INCREASING RAIN POTENTIAL LATER THIS AFTERNOON INTO TONIGHT ALONG WITH POTENTIAL HYDROLOGIC IMPACTS. WATER VAPOR IMAGERY EARLY THIS MORNING DEPICTS DIGGING UPPER TROUGH APPROACHING THE CENTRAL PLAINS WITH SECONDARY WEAKER SHORT WAVE APPROACHING WEST TEXAS. MODEL GUIDANCE HAS BEEN FAIRLY CONSISTENT IN MAINTAINING AN UNPHASED NATURE WITH THESE TWO SHORT WAVES...QUICKLY TAKING THE WEST TEXAS VORT MAX INTO THE WESTERN GREAT LAKES THIS EVENING. BROAD WARM/MOIST ADVECTION TO OCCUR TODAY...WITH MORE FOCUSED AXIS OF DEEPER MOISTURE SETTING UP IN VICINITY OF LOW/MID LEVEL CONFLUENCE ZONE ACROSS THE WESTERN GREAT LAKES. HAVE CONTINUED UPWARD TREND TO CATEGORICAL POPS FOR LATE THIS AFTERNOON ACROSS APPROXIMATELY WESTERN THIRD OF THE AREA WITH PERIODS OF MODERATE RAIN EXPECTED IN THE 21Z-03Z TIMEFRAME. ON HEELS OF THIS LEAD WAVE...EXPECTING LARGER SCALE FRONTAL RESPONSE TO INCREASE ACROSS THE MID MS RIVER VALLEY EARLY THIS EVENING IN ADVANCE OF MORE AMPLIFIED CENTRAL PLAINS TROUGH. A STRONG LLJ WILL VEER THIS EVENING IN ADVANCE OF THIS TROUGH AND SHOULD ADVECT PRIMARY LOW LEVEL THERMAL/MOIST AXIS ACROSS SERN PORTIONS OF THE FORECAST AREA LATER THIS EVENING INTO THE OVERNIGHT HOURS. PREFRONTAL CONVERGENCE AXIS SHOULD BE PROGRESSIVE ACROSS THE AREA SO CONFIDENCE SOMEWHAT LOW ON EXACT RAINFALL AMOUNTS ACROSS SOUTHEAST OF THE AREA WITH POTENTIAL OF HEAVIEST AMOUNTS REMAINING JUST TO EAST AND SOUTHEAST. HAVE MADE VERY FEW CHANGES TO PREVIOUS FORECAST WITH RAINFALL AMOUNTS IN THE HALF INCH TO INCH RANGE. IN ADDITION TO THIS RAIN...EXISTING SNOWPACK DOES CONTAIN 1 TO 2 INCHES OF LIQUID EQUIVALENT...WITH 2+ INCHES ACROSS THE FAR NORTH ACROSS SOUTHERN LOWER MICHIGAN. STILL SOME UNCERTAINTY AS TO EXTENT/TIMING OF RUNOFF FROM RAIN/SNOWMELT GIVEN FLUCTUATING SFC TEMPS OVER THE NEXT FEW DAYS. IF HIGHER END OF FORECASTED RAINFALL AMOUNTS DO OCCUR...PORTIONS OF MAUMEE AND WABASH RIVER BASINS STILL APPEAR TO STAND GREATEST RISK OF MINOR FLOODING OVER NEXT FEW DAYS GIVEN WARMER LOW LEVEL PROFILES AND GREATER RUNOFF FROM SNOWMELT. ACROSS THE FAR NORTH WHERE GREATER LIQUID EQUIVALENT IN SNOWPACK EXISTS...CONFIDENCE REMAINS SOMEWHAT LOWER IN TERMS OF EXTENT/TIMING OF SNOWMELT GIVEN COOLER LOW LEVEL TEMPS ACROSS THESE LOCATIONS. HOWEVER...GIVEN MORE FAVORABLE TRACK WITH INITIAL SHORT WAVE THIS EVENING...SOME LOCALLY HIGHER RAINFALL AMOUNTS ARE POSSIBLE TONIGHT ACROSS ESPECIALLY WESTERN PORTIONS OF ST. JOSEPH BASIN. WILL CONTINUE WITH ESF THIS MORNING TO DISCUSS POSSIBLE HYDRO IMPACTS OVER THE NEXT SEVERAL DAYS. && .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 420 AM EST FRI JAN 10 2014 VORT MAX WILL BE SWEEPING ACROSS THE CWA AT THE START OF THE PERIOD...WITH RAIN QUICKLY SHIFTING WEST TO EAST DURING THE MORNING HOURS AS COLD FRONT USHERS IN A QUICK SHOT OF COOLER AIR. THIS WILL ALLOW A BRIEF PERIOD FOR RAIN/SNOW MIX ACROSS THE AREA. HOWEVER...BY THIS POINT DEEPEST MSTR AND LIFT WILL BE SHIFTING EAST...KEEPING ANY ACCUMULATION POTENTIAL TO A MINIMUM. PREV FORECAST GENERALLY LEFT INTACT. 925 MB TEMPS WILL BOTTOM OUT AROUND -5 C BY LATE SAT NGT...TRANSLATING TO LOWS IN THE MID TO UPR 20S...STILL A GOOD 10 DEGREES OR MORE ABOVE NORMAL FOR MID JANUARY. UPPER LEVEL RIDGING WILL QUICKLY MOVE BACK IN BY SUNDAY WITH RETURN TO ABOVE NORMAL TEMPS IN TO THE 30S AND POSSIBLY LOW 40S WITH EFFECTS OF SNOWPACK BEING GREATLY REDUCED. TEMPS WILL STAY ABOVE FREEZING INTO MONDAY IN ADVANCE OF YET ANOTHER NORTHERN STREAM TROUGH TO BRING A CHANCE OF RAIN. A FEW OF THE MODELS SHOW POTENTIAL INTERACTION WITH SOUTHERN STREAM ENERGY BUT EVEN THE STRONGEST ECMWF ONLY SHOWS A SHARPENING OF THE PROGRESSIVE TROUGH. STATUS QUO FOR THE TIME BEING MON/MON NGT WITH CHC POPS AS BEST POTENTIAL REMAINS N AND S OF THE AREA. ACTIVE PATTERN CONTINUES WITH OVERALL LONGWAVE TROUGH REMAINING IN PLACE ACROSS THE GREAT LAKES WITH A STRONGER WAVE DROPPING THROUGH FOR MID WEEK. MODELS DIVERGE EVEN FURTHER WITH ECMWF CLOSING OFF A PROGRESSIVE UPPER LOW OVER THE CAROLINAS BY WEDNESDAY EVENING. WILL KEEP CONSERVATIVE LOW END POPS IN N AREAS THURSDAY AS MAIN TROUGH MOVES IN. TEMPERATURES WILL HOVER EITHER SIDE OF NORMAL WITH WARM UPS AHEAD OF EACH WAVE AND DROP TO SLIGHTLY BELOW NORMAL BEHIND IT. SOME INDICATIONS OF RETURN OF COLDER...BELOW NORMAL AIR OUTSIDE THE PERIOD BUT BY FAR MUCH WARMER THAN RECENT POLAR BLAST. FLOODING CONCERNS WILL LIKELY LINGER THROUGH MUCH OF THE PERIOD...BUT EXACT MAGNITUDE WILL BE TRICKY TO SORT OUT AS MUCH OF IT WILL FOCUS ON QPF OVER THE NEXT DAY OR SO. WILL CONTINUE WITH HWO MENTION INTO MID WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1223 PM EST FRI JAN 10 2014 IFR CONDITIONS WILL PERSIST THROUGH MUCH OF THE PERIOD AS MOIST SOUTHERLY FLOW CONTINUES OVER AN EXISTING/MELTING SNOWPACK. MAY SEE A BRIEF PERIOD OF MVFR AT MAINLY FWA THIS AFTN BEFORE WIDESPREAD RAIN/IFR SPREADS INTO NORTHERN INDIANA EARLY THIS EVENING AND LINGERS INTO FRIDAY MORNING. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...DENSE FOG ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR INZ003>007. MI...DENSE FOG ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR MIZ077>081. OH...NONE. LM...NONE. && $$ SYNOPSIS...MARSILI SHORT TERM...MARSILI LONG TERM...FISHER AVIATION...STEINWEDEL VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION...CORRECTED UPDATE
NWS QUAD CITIES IA IL
453 PM CST FRI JAN 10 2014 .UPDATE... ISSUED AT 444 PM CST FRI JAN 10 2014 EXPANDED ADVISORY TO INCLUDE JACKSON COUNTY IN IOWA AND JO DAVIESS AND STEPHENSON COUNTIES IN FAR NORTHERN ILLINOIS. REPORTS OF SEVERAL ROADS COMPLETELY COVERED IN JACKSON COUNTY... IA38...IA136 IA64. PAVEMENT TEMPS HOVERING AROUND FREEZING IN THESE AREAS ALLOWING FOR THE ICY CONDITIONS TO DEVELOP. COULD ACTUALLY SEE SOME IMPROVEMENT FOR A TIME THIS EVENING AS TEMPS CONTINUE TO SLOWLY CLIMB AHEAD OF AN APPROACHING SURFACE LOW. HOWEVER....ONCE THIS PASSES AND WINDS SHIFT TO WEST WILL SEE TEMPS DROP LATE THIS EVE AND OVERNIGHT AND MAY SEE MORE ICING WHETHER THROUGH REFREEZE OR POSSIBLY SOME LIGHT FREEZING DRIZZLE/FREEZING RAIN. UPDATE ISSUED AT 336 PM CST FRI JAN 10 2014 CALLS ARE NOW COMING IN REPORTING SLICK ROADS. THUS WILL HOIST A FREEZING RAIN ADVISORY FOR LATE AFTERNOON AND EVENING. TEMPORAL AND AREAL COVERAGE OF THE ADVISORY MAY NEED TO CHANGED THIS EVENING. && .SYNOPSIS... ISSUED AT 248 PM CST FRI JAN 10 2014 12Z UA ANALYSIS HAS A LLJ RUNNING FROM TEXAS INTO WESTERN MISSOURI. MOISTURE ASSOCIATED WITH THIS JET WAS IMPINGING UPON AN 850 MB WARM FRONT RUNNING FROM KANSAS INTO SOUTHERN ILLINOIS. RADAR TRENDS THROUGH MID AFTERNOON HAD A LARGE AREA OF RAIN FROM MISSOURI INTO ILLINOIS WITH LIGHTER RAIN/DRIZZLE MIXED WITH SOME FREEZING RAIN/DRIZZLE ACROSS IOWA. 18Z SFC ANALYSIS HAS A WEAK LOW NEAR KMHK WITH A WARM FRONT EAST ALONG THE MISSOURI RIVER. THE COLD FRONT RAN FROM THE LOW INTO SOUTHWEST OKLAHOMA. DEW POINTS WERE IN THE 20S AND 30S ACROSS THE UPPER MIDWEST AND GREAT LAKES WITH 40S AND HIGHER FROM THE OHIO VALLEY AND SOUTHERN PLAINS. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 248 PM CST FRI JAN 10 2014 BASED ON TRENDS FROM PRESSURE FALLS AND THE RAP MODEL...THE LOW SHOULD PASS OVER THE FAR NORTHWEST AREA BETWEEN KALO AND KCID THIS EVENING. WINDS WILL DECREASE AS THE LOW APPROACHES AND THE FOG IS EXPECTED TO BECOME MORE WIDESPREAD. RIGHT NOW NO ADVISORY FOR DENSE FOG IS PLANNED. HOWEVER...I WOULD NOT BE SURPRISED IF ONE IS NEEDED AT SOME POINT DURING THE EVENING. TEMPERATURES HAVE NOT BUDGED MUCH IN THE HIGHWAY 20 CORRIDOR FROM KDBQ ON WEST. THUS THIS AREA IS RIGHT ON THE CUSP OF SEEING FREEZING RAIN LATE THIS AFTERNOON AND EVENING AS LIFT CONTINUES TO INCREASE. HOWEVER...THE TRACK OF THE LOW SHOULD ALLOW TEMPERATURES TO RISE ABOUT ANOTHER DEGREE. FREEZING RAIN IS EXPECTED TO BE LOCALLY SPOTTY OVER THE FOUR NORTHWEST COUNTIES AND POSSIBLY WESTERN DUBUQUE COUNTY THROUGH MID EVENING. ONCE THE LOW PASSES...COLD AIR WILL SLOWLY BEGIN TO MOVE INTO THE AREA ALLOWING THE RAIN TO MIX WITH AND CHANGE TO SNOW FROM WEST TO EAST OVERNIGHT. DURING THE CHANGE OVER...A BRIEF PERIOD OF FREEZING RAIN WILL BE POSSIBLE. SNOW AMOUNTS WILL RANGE FROM A TRACE TO UNDER AN INCH. ON SATURDAY...LINGERING LIGHT SNOW WILL BE SEE OVER ROUGHLY THE NORTHEAST/EAST HALF OF THE AREA DURING THE MORNING. OTHERWISE DRY CONDITIONS ARE EXPECTED DURING THE DAY. SNOW AMOUNTS SATURDAY MORNING WILL BE A DUSTING AT BEST. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 248 PM CST FRI JAN 10 2014 NEARLY ZONAL UPPER AIR FLOW WILL BE OVER THE AREA THE REST OF THE WEEKEND THEN THE PATTERN CHANGES TO A RIDGE DOMINATED WESTERN U.S. AND A MEAN TROF SETTING UP OVER THE EAST. MILD CONDITIONS ARE ANTICIPATED FOR THE REGION SUNDAY AS UPPER RIDGING BUILDS OVER THE AREA SATURDAY NIGHT INTO SUNDAY. IN THE LOW LEVELS A SURFACE RIDGE WILL MOVE THROUGH THE REGION SATURDAY EVENING FOLLOWED BY STRONG LOW LEVEL WAA AHEAD OF A TROF DIGGING INTO THE SOUTHWEST U.S. AND A COLD FRONT OVER THE PLAINS. A LOW LEVEL THERMAL RIDGE CROSSES THE MID MISSISSIPPI VALLEY SUNDAY WITH H8 TEMPS PEAKING IN THE +8 TO +10C RANGE DURING THE AFTERNOON. GOOD MIXING IS ALSO SUGGESTED WITH A TIGHT SLP GRADIENT AHEAD OF THE COLD FRONT. EVEN WITH THE SNOW COVER...WE SHOULD SEE HIGHS TOPPING OUT IN THE MID 30S TO MID 40S. MODELS MOVE THE FRONT THROUGH THE REGION WITH OUT ANY PRECIPITATION SUNDAY NIGHT. THIS LOOKS REASONABLE WITH THE BETTER MOISTURE GETTING PUSHED OUT WELL AHEAD OF THE SYSTEM. THERE IS SOME CONCERN MONDAY WITH THE LESS PHASED ECM SOLUTION LIFTING A PIECE OF THE UPPER TROF OUT OF TEXAS...SENDING A SURFACE LOW NORTHEAST THROUGH THE OHIO VALLEY. THE ECMS PRECIP SHIELD WITH THIS FEATURE JUST MISSES THE SOUTHEAST CWFA MONDAY. MODELS DO AGREE ON A WEAK S/W RACING SOUTHEAST THROUGH THE DAKOTAS AND MN MONDAY AND MONDAY NIGHT WITH THE LATEST RUNS MOVING IT/S WEAK SURFACE LOW THROUGH IA AND FAVOR THE NORTHEAST CWFA FOR SOME LOW POPS FOR LIGHT SNOW. JUST A QUICK SHOT OF COLD AIR IS EXPECTED BEHIND THIS FEATURE WITH THE COLDEST TEMPS EXPECTED WEDNESDAY MORNING WITH LOWS IN THE SINGLE DIGITS AND TEENS. FOR THE END OF THE WEEK ANOTHER S/W MOVING OUT OF THE CANADIAN ROCKIES WILL SEND A SURFACE LOW EAST ALONG THE U.S. CANADIAN BORDER...DRAGGING A COLD FRONT THROUGH THE REGION WEDNESDAY NIGHT OR THURSDAY MORNING. THE FRONT SHOULD MOVE THROUGH DRY WITH A LARGE AREA OF HIGH PRESSURE OVER THE WESTERN GULF BLOCKING ANY MOISTURE RETURN. BUT THE NORTHEAST COULD SEE SOME LIGHT SNOW IN THE CYCLONIC FLOW AROUND THE SURFACE LOW AS IT MOVES INTO EASTERN CANADA THURSDAY NIGHT AND FRIDAY. MODELS SHOW THE SYSTEM DRAGGING DOWN ANOTHER CHUNK OF ARCTIC AIR WITH BOTH THE ECM AND GFS BRINGING H8 TEMPS AS COLD AS -22C OVER THE AREA THURSDAY NIGHT. THIS COULD RESULT IN SUBZERO TEMPERATURES OVER THE NORTH BY SATURDAY MORNING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1208 PM CST FRI JAN 10 2014 LIFR/VLIFR CONDITIONS WILL CONTINUE THROUGH 12Z/11 WITH THE POTENTIAL FOR CONDITIONS TO BE BELOW MINIMUMS. LOW PRESSURE WILL TRACK UP THROUGH EASTERN IOWA THIS EVENING BEFORE MOVING INTO WISCONSIN. FRONTAL PASSAGE AFTER 03Z/11 WILL BRING THE RISK OF MIXED PRECIPITATION WITH A BRIEF PERIOD OF FZRA BEFORE CHANGING TO SNOW. AFTER 12Z/11 CONDITIONS WILL SLOWLY IMPROVE TO MVFR. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...FREEZING RAIN ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BENTON- BUCHANAN-DELAWARE-DUBUQUE-JACKSON-JONES-LINN. IL...FREEZING RAIN ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR JO DAVIESS- STEPHENSON. MO...NONE. && $$ UPDATE...05 SYNOPSIS...08 SHORT TERM...08 LONG TERM...DLF AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
339 PM CST FRI JAN 10 2014 .UPDATE... ISSUED AT 336 PM CST FRI JAN 10 2014 CALLS ARE NOW COMING IN REPORTING SLICK ROADS. THUS WILL HOIST A FREEZING RAIN ADVISORY FOR LATE AFTERNOON AND EVENING. TEMPORAL AND AREAL COVERAGE OF THE ADVISORY MAY NEED TO CHANGED THIS EVENING. && .SYNOPSIS... ISSUED AT 248 PM CST FRI JAN 10 2014 12Z UA ANALYSIS HAS A LLJ RUNNING FROM TEXAS INTO WESTERN MISSOURI. MOISTURE ASSOCIATED WITH THIS JET WAS IMPINGING UPON AN 850 MB WARM FRONT RUNNING FROM KANSAS INTO SOUTHERN ILLINOIS. RADAR TRENDS THROUGH MID AFTERNOON HAD A LARGE AREA OF RAIN FROM MISSOURI INTO ILLINOIS WITH LIGHTER RAIN/DRIZZLE MIXED WITH SOME FREEZING RAIN/DRIZZLE ACROSS IOWA. 18Z SFC ANALYSIS HAS A WEAK LOW NEAR KMHK WITH A WARM FRONT EAST ALONG THE MISSOURI RIVER. THE COLD FRONT RAN FROM THE LOW INTO SOUTHWEST OKLAHOMA. DEW POINTS WERE IN THE 20S AND 30S ACROSS THE UPPER MIDWEST AND GREAT LAKES WITH 40S AND HIGHER FROM THE OHIO VALLEY AND SOUTHERN PLAINS. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 248 PM CST FRI JAN 10 2014 BASED ON TRENDS FROM PRESSURE FALLS AND THE RAP MODEL...THE LOW SHOULD PASS OVER THE FAR NORTHWEST AREA BETWEEN KALO AND KCID THIS EVENING. WINDS WILL DECREASE AS THE LOW APPROACHES AND THE FOG IS EXPECTED TO BECOME MORE WIDESPREAD. RIGHT NOW NO ADVISORY FOR DENSE FOG IS PLANNED. HOWEVER...I WOULD NOT BE SURPRISED IF ONE IS NEEDED AT SOME POINT DURING THE EVENING. TEMPERATURES HAVE NOT BUDGED MUCH IN THE HIGHWAY 20 CORRIDOR FROM KDBQ ON WEST. THUS THIS AREA IS RIGHT ON THE CUSP OF SEEING FREEZING RAIN LATE THIS AFTERNOON AND EVENING AS LIFT CONTINUES TO INCREASE. HOWEVER...THE TRACK OF THE LOW SHOULD ALLOW TEMPERATURES TO RISE ABOUT ANOTHER DEGREE. FREEZING RAIN IS EXPECTED TO BE LOCALLY SPOTTY OVER THE FOUR NORTHWEST COUNTIES AND POSSIBLY WESTERN DUBUQUE COUNTY THROUGH MID EVENING. ONCE THE LOW PASSES...COLD AIR WILL SLOWLY BEGIN TO MOVE INTO THE AREA ALLOWING THE RAIN TO MIX WITH AND CHANGE TO SNOW FROM WEST TO EAST OVERNIGHT. DURING THE CHANGE OVER...A BRIEF PERIOD OF FREEZING RAIN WILL BE POSSIBLE. SNOW AMOUNTS WILL RANGE FROM A TRACE TO UNDER AN INCH. ON SATURDAY...LINGERING LIGHT SNOW WILL BE SEE OVER ROUGHLY THE NORTHEAST/EAST HALF OF THE AREA DURING THE MORNING. OTHERWISE DRY CONDITIONS ARE EXPECTED DURING THE DAY. SNOW AMOUNTS SATURDAY MORNING WILL BE A DUSTING AT BEST. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 248 PM CST FRI JAN 10 2014 NEARLY ZONAL UPPER AIR FLOW WILL BE OVER THE AREA THE REST OF THE WEEKEND THEN THE PATTERN CHANGES TO A RIDGE DOMINATED WESTERN U.S. AND A MEAN TROF SETTING UP OVER THE EAST. MILD CONDITIONS ARE ANTICIPATED FOR THE REGION SUNDAY AS UPPER RIDGING BUILDS OVER THE AREA SATURDAY NIGHT INTO SUNDAY. IN THE LOW LEVELS A SURFACE RIDGE WILL MOVE THROUGH THE REGION SATURDAY EVENING FOLLOWED BY STRONG LOW LEVEL WAA AHEAD OF A TROF DIGGING INTO THE SOUTHWEST U.S. AND A COLD FRONT OVER THE PLAINS. A LOW LEVEL THERMAL RIDGE CROSSES THE MID MISSISSIPPI VALLEY SUNDAY WITH H8 TEMPS PEAKING IN THE +8 TO +10C RANGE DURING THE AFTERNOON. GOOD MIXING IS ALSO SUGGESTED WITH A TIGHT SLP GRADIENT AHEAD OF THE COLD FRONT. EVEN WITH THE SNOW COVER...WE SHOULD SEE HIGHS TOPPING OUT IN THE MID 30S TO MID 40S. MODELS MOVE THE FRONT THROUGH THE REGION WITH OUT ANY PRECIPITATION SUNDAY NIGHT. THIS LOOKS REASONABLE WITH THE BETTER MOISTURE GETTING PUSHED OUT WELL AHEAD OF THE SYSTEM. THERE IS SOME CONCERN MONDAY WITH THE LESS PHASED ECM SOLUTION LIFTING A PIECE OF THE UPPER TROF OUT OF TEXAS...SENDING A SURFACE LOW NORTHEAST THROUGH THE OHIO VALLEY. THE ECMS PRECIP SHIELD WITH THIS FEATURE JUST MISSES THE SOUTHEAST CWFA MONDAY. MODELS DO AGREE ON A WEAK S/W RACING SOUTHEAST THROUGH THE DAKOTAS AND MN MONDAY AND MONDAY NIGHT WITH THE LATEST RUNS MOVING IT/S WEAK SURFACE LOW THROUGH IA AND FAVOR THE NORTHEAST CWFA FOR SOME LOW POPS FOR LIGHT SNOW. JUST A QUICK SHOT OF COLD AIR IS EXPECTED BEHIND THIS FEATURE WITH THE COLDEST TEMPS EXPECTED WEDNESDAY MORNING WITH LOWS IN THE SINGLE DIGITS AND TEENS. FOR THE END OF THE WEEK ANOTHER S/W MOVING OUT OF THE CANADIAN ROCKIES WILL SEND A SURFACE LOW EAST ALONG THE U.S. CANADIAN BORDER...DRAGGING A COLD FRONT THROUGH THE REGION WEDNESDAY NIGHT OR THURSDAY MORNING. THE FRONT SHOULD MOVE THROUGH DRY WITH A LARGE AREA OF HIGH PRESSURE OVER THE WESTERN GULF BLOCKING ANY MOISTURE RETURN. BUT THE NORTHEAST COULD SEE SOME LIGHT SNOW IN THE CYCLONIC FLOW AROUND THE SURFACE LOW AS IT MOVES INTO EASTERN CANADA THURSDAY NIGHT AND FRIDAY. MODELS SHOW THE SYSTEM DRAGGING DOWN ANOTHER CHUNK OF ARCTIC AIR WITH BOTH THE ECM AND GFS BRINGING H8 TEMPS AS COLD AS -22C OVER THE AREA THURSDAY NIGHT. THIS COULD RESULT IN SUBZERO TEMPERATURES OVER THE NORTH BY SATURDAY MORNING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1208 PM CST FRI JAN 10 2014 LIFR/VLIFR CONDITIONS WILL CONTINUE THROUGH 12Z/11 WITH THE POTENTIAL FOR CONDITIONS TO BE BELOW MINIMUMS. LOW PRESSURE WILL TRACK UP THROUGH EASTERN IOWA THIS EVENING BEFORE MOVING INTO WISCONSIN. FRONTAL PASSAGE AFTER 03Z/11 WILL BRING THE RISK OF MIXED PRECIPITATION WITH A BRIEF PERIOD OF FZRA BEFORE CHANGING TO SNOW. AFTER 12Z/11 CONDITIONS WILL SLOWLY IMPROVE TO MVFR. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...FREEZING RAIN ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BENTON- BUCHANAN-DELAWARE-DUBUQUE-JONES-LINN. IL...NONE. MO...NONE. && $$ UPDATE...08 SYNOPSIS...08 SHORT TERM...08 LONG TERM...DLF AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
250 PM CST FRI JAN 10 2014 .SYNOPSIS... ISSUED AT 248 PM CST FRI JAN 10 2014 12Z UA ANALYSIS HAS A LLJ RUNNING FROM TEXAS INTO WESTERN MISSOURI. MOISTURE ASSOCIATED WITH THIS JET WAS IMPINGING UPON AN 850 MB WARM FRONT RUNNING FROM KANSAS INTO SOUTHERN ILLINOIS. RADAR TRENDS THROUGH MID AFTERNOON HAD A LARGE AREA OF RAIN FROM MISSOURI INTO ILLINOIS WITH LIGHTER RAIN/DRIZZLE MIXED WITH SOME FREEZING RAIN/DRIZZLE ACROSS IOWA. 18Z SFC ANALYSIS HAS A WEAK LOW NEAR KMHK WITH A WARM FRONT EAST ALONG THE MISSOURI RIVER. THE COLD FRONT RAN FROM THE LOW INTO SOUTHWEST OKLAHOMA. DEW POINTS WERE IN THE 20S AND 30S ACROSS THE UPPER MIDWEST AND GREAT LAKES WITH 40S AND HIGHER FROM THE OHIO VALLEY AND SOUTHERN PLAINS. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 248 PM CST FRI JAN 10 2014 BASED ON TRENDS FROM PRESSURE FALLS AND THE RAP MODEL...THE LOW SHOULD PASS OVER THE FAR NORTHWEST AREA BETWEEN KALO AND KCID THIS EVENING. WINDS WILL DECREASE AS THE LOW APPROACHES AND THE FOG IS EXPECTED TO BECOME MORE WIDESPREAD. RIGHT NOW NO ADVISORY FOR DENSE FOG IS PLANNED. HOWEVER...I WOULD NOT BE SURPRISED IF ONE IS NEEDED AT SOME POINT DURING THE EVENING. TEMPERATURES HAVE NOT BUDGED MUCH IN THE HIGHWAY 20 CORRIDOR FROM KDBQ ON WEST. THUS THIS AREA IS RIGHT ON THE CUSP OF SEEING FREEZING RAIN LATE THIS AFTERNOON AND EVENING AS LIFT CONTINUES TO INCREASE. HOWEVER...THE TRACK OF THE LOW SHOULD ALLOW TEMPERATURES TO RISE ABOUT ANOTHER DEGREE. FREEZING RAIN IS EXPECTED TO BE LOCALLY SPOTTY OVER THE FOUR NORTHWEST COUNTIES AND POSSIBLY WESTERN DUBUQUE COUNTY THROUGH MID EVENING. ONCE THE LOW PASSES...COLD AIR WILL SLOWLY BEGIN TO MOVE INTO THE AREA ALLOWING THE RAIN TO MIX WITH AND CHANGE TO SNOW FROM WEST TO EAST OVERNIGHT. DURING THE CHANGE OVER...A BRIEF PERIOD OF FREEZING RAIN WILL BE POSSIBLE. SNOW AMOUNTS WILL RANGE FROM A TRACE TO UNDER AN INCH. ON SATURDAY...LINGERING LIGHT SNOW WILL BE SEE OVER ROUGHLY THE NORTHEAST/EAST HALF OF THE AREA DURING THE MORNING. OTHERWISE DRY CONDITIONS ARE EXPECTED DURING THE DAY. SNOW AMOUNTS SATURDAY MORNING WILL BE A DUSTING AT BEST. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 248 PM CST FRI JAN 10 2014 NEARLY ZONAL UPPER AIR FLOW WILL BE OVER THE AREA THE REST OF THE WEEKEND THEN THE PATTERN CHANGES TO A RIDGE DOMINATED WESTERN U.S. AND A MEAN TROF SETTING UP OVER THE EAST. MILD CONDITIONS ARE ANTICIPATED FOR THE REGION SUNDAY AS UPPER RIDGING BUILDS OVER THE AREA SATURDAY NIGHT INTO SUNDAY. IN THE LOW LEVELS A SURFACE RIDGE WILL MOVE THROUGH THE REGION SATURDAY EVENING FOLLOWED BY STRONG LOW LEVEL WAA AHEAD OF A TROF DIGGING INTO THE SOUTHWEST U.S. AND A COLD FRONT OVER THE PLAINS. A LOW LEVEL THERMAL RIDGE CROSSES THE MID MISSISSIPPI VALLEY SUNDAY WITH H8 TEMPS PEAKING IN THE +8 TO +10C RANGE DURING THE AFTERNOON. GOOD MIXING IS ALSO SUGGESTED WITH A TIGHT SLP GRADIENT AHEAD OF THE COLD FRONT. EVEN WITH THE SNOW COVER...WE SHOULD SEE HIGHS TOPPING OUT IN THE MID 30S TO MID 40S. MODELS MOVE THE FRONT THROUGH THE REGION WITH OUT ANY PRECIPITATION SUNDAY NIGHT. THIS LOOKS REASONABLE WITH THE BETTER MOISTURE GETTING PUSHED OUT WELL AHEAD OF THE SYSTEM. THERE IS SOME CONCERN MONDAY WITH THE LESS PHASED ECM SOLUTION LIFTING A PIECE OF THE UPPER TROF OUT OF TEXAS...SENDING A SURFACE LOW NORTHEAST THROUGH THE OHIO VALLEY. THE ECMS PRECIP SHIELD WITH THIS FEATURE JUST MISSES THE SOUTHEAST CWFA MONDAY. MODELS DO AGREE ON A WEAK S/W RACING SOUTHEAST THROUGH THE DAKOTAS AND MN MONDAY AND MONDAY NIGHT WITH THE LATEST RUNS MOVING IT/S WEAK SURFACE LOW THROUGH IA AND FAVOR THE NORTHEAST CWFA FOR SOME LOW POPS FOR LIGHT SNOW. JUST A QUICK SHOT OF COLD AIR IS EXPECTED BEHIND THIS FEATURE WITH THE COLDEST TEMPS EXPECTED WEDNESDAY MORNING WITH LOWS IN THE SINGLE DIGITS AND TEENS. FOR THE END OF THE WEEK ANOTHER S/W MOVING OUT OF THE CANADIAN ROCKIES WILL SEND A SURFACE LOW EAST ALONG THE U.S. CANADIAN BORDER...DRAGGING A COLD FRONT THROUGH THE REGION WEDNESDAY NIGHT OR THURSDAY MORNING. THE FRONT SHOULD MOVE THROUGH DRY WITH A LARGE AREA OF HIGH PRESSURE OVER THE WESTERN GULF BLOCKING ANY MOISTURE RETURN. BUT THE NORTHEAST COULD SEE SOME LIGHT SNOW IN THE CYCLONIC FLOW AROUND THE SURFACE LOW AS IT MOVES INTO EASTERN CANADA THURSDAY NIGHT AND FRIDAY. MODELS SHOW THE SYSTEM DRAGGING DOWN ANOTHER CHUNK OF ARCTIC AIR WITH BOTH THE ECM AND GFS BRINGING H8 TEMPS AS COLD AS -22C OVER THE AREA THURSDAY NIGHT. THIS COULD RESULT IN SUBZERO TEMPERATURES OVER THE NORTH BY SATURDAY MORNING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1208 PM CST FRI JAN 10 2014 LIFR/VLIFR CONDITIONS WILL CONTINUE THROUGH 12Z/11 WITH THE POTENTIAL FOR CONDITIONS TO BE BELOW MINIMUMS. LOW PRESSURE WILL TRACK UP THROUGH EASTERN IOWA THIS EVENING BEFORE MOVING INTO WISCONSIN. FRONTAL PASSAGE AFTER 03Z/11 WILL BRING THE RISK OF MIXED PRECIPITATION WITH A BRIEF PERIOD OF FZRA BEFORE CHANGING TO SNOW. AFTER 12Z/11 CONDITIONS WILL SLOWLY IMPROVE TO MVFR. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SYNOPSIS...08 SHORT TERM...08 LONG TERM...DLF AVIATION...08
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1204 PM CST Fri Jan 10 2014 ...Updated Aviation Section... .SHORT TERM...(Today and tonight) ISSUED AT 1251 AM CST FRI JAN 10 2014 This morning: Immediate near term concern is fog. Issued a dense fog advisory earlier based off HRRR and WRF visibilities as well a trend in the observations. Winds have remained elevated as the warm sector has spread across SW Kansas early this morning. Will continue with the advisory as is and later shifts can cancel or trim counties as seen fit. Downslope/dry air advection is expected later today in the wake of a passing cold front, which should scour low level moisture out. Today: A synoptic trof ushering in the passage of said front will move across the region through the day. Mesoscale and global models have a hint of QPF across NW Kansas at the base of the 400 hPa PVU hook. Not overly impressive for my counties as isentropic downglide develops in earnest with the passage of the trof. Will go with ghost probability percentage precipitation points for now up north. Otherwise, Boise verification shows a bias in recent temperatures forecasts, and will trend with the GEM for now, which has been performing better recently. Low 40sF northwest to upper 40sF southeast. Tonight: Westerly to northwesterly flow at the surface and a dry northwesterly flow aloft will continue tonight. Continued dry air advection with resultant decreasing dewpoints and weaker winds favor cooler minimum temperatures through the overnight - 20sF. .LONG TERM...(Saturday through Thursday) ISSUED AT 320 AM CST FRI JAN 10 2014 No precipitation is anticipated for the days 2 through 7 period. No strong upper level feature will be crossing the plains, and a couple of fronts will pass through dry. Saturday will see an upper level trough over the Mississippi Valley, and the 500mb flow from the northwest across western Kansas. A broad ridge aloft will drift across the plains, bringing mostly sunny skies and warming temperatures this weekend. Saturday will see highs in the middle 50s, and then warming into the mid 50s to lower 60s on Sunday. The upper flow pattern will turn to zonal on Monday, bringing a few upper level clouds and just a slight cool down to temperatures. Monday`s highs will range in the lower 50s in central Kansas to near the mid 50s along the Oklahoma border. Tuesday will bring a cool down, with highs in the upper 40s north of I-70 to the lower 50s near Meade and Ashland. Then we will return to a down slope, northwesterly flow aloft Wednesday. A warm front should shoot northeastward through western Kansas Tuesday night, and bring maximum temperatures in the middle 50s for most locations in southwestern Kansas on Wednesday. Minimum temperatures throughout the Saturday through Friday period will average from the middle 20s to the middle 30s. Surface winds will generally be northwest 15 mph gusting 25 mph during most afternoons. The winds will die down in the evening, and be less than 10 mph during the night time periods. The only night that will be an exception to that will be Tuesday night behind the frontal passage, with north winds at 15 to 20 mph. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 1155 AM CST FRI JAN 10 2014 An upper disturbance and associated surface low over Kansas this early afternoon, will shift quickly east into the Mississippi Valley by early evening. This will move a band of light snow with mvfr ceilings over north central Kansas this morning, east of Hays by mid afternoon with an unlimited ceiling and visibility prevailing through the remainder of the period. Winds will increase behind the exiting surface low and may approach sustained speeds of 25 knots at DDC and HYS terminals but confidence is not high enough at this point to increase speeds to this level. && .PRELIMINARY POINT TEMPS/POPS... DDC 46 24 57 30 / 10 0 0 0 GCK 44 22 56 29 / 0 0 0 0 EHA 48 26 62 33 / 0 0 0 0 LBL 48 21 60 31 / 0 0 0 0 HYS 44 24 54 29 / 90 0 0 0 P28 50 25 59 31 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Sugden SHORT TERM...Sugden LONG TERM...Burke AVIATION...AJohnson
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
441 PM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE MOVES OFFSHORE TODAY AND TONIGHT AS A SERIES OF WEAK UPPER LEVEL TROUGHS TRACK ACROSS THE MID ATLANTIC REGION. A COLD FRONT APPROACHES FROM THE WEST SATURDAY AND PUSHES THROUGH THE REGION SATURDAY NIGHT EVENING. HIGH PRESSURE RETURNS FROM THE WEST LATER SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... LATEST SURFACE ANALYSIS INDICATES A ~1034MB SFC HIGH PRESSURE NOW WELL OFF THE NEW ENGLAND COASTLINE...WITH A SFC RIDGE AXIS EXTENDING SW ALONG THE PIEDMONT INTO NE GA. TO THE SOUTHEAST, A COASTAL TROUGH HAS NOW LIFTED INLAND ACROSS THE COASTAL CAROLINAS...AND BRIEFLY LIFTED ACROSS FAR SE TIP OF THE COMMONWEALTH EARLY THIS AFTN (TEMPS JUMPED INTO THE LOW 60S EARLY THIS AFTN BEFORE DROPPING BACK INTO THE U40S OVER THE PAST FEW HRS). WARM/MOIST ADVECTION CONTINUES THIS AFTN...WITH SHRAS IN ASSN WITH THE LATEST SLUG OF OVERRUNNING MOISTURE MOVING ACROSS THE REGION ATTM. WV SAT IMAGERY SHOWING DISTURBANCE RESPONSIBLE FOR THIS LATEST ROUND OF SHRAS LIFTING E-NE ACROSS THE LOWER MID- ATLANTIC IN SSW FLOW ALOFT. OCCASIONAL LIGHT RAINFALL WILL CONTINUE OVER THE NEXT FEW HOURS AS THIS WAVE MOVES THROUGH...WITH SHRAS BECOMING LESS WIDESPREAD LATE TONIGHT AND ESPECIALLY AFTER MIDNIGHT AS FRONT SHIFTS NORTH. FOR TEMPS, WE`VE FOLLOWED THE LEAD OF THE HRRR AND HIGH RES NAM W/TEMP TRENDS THROUGH EARLY SAT MORNING. EXPECT TEMPS WILL FALL VERY LITTLE EARLY TONIGHT ACROSS CENTRAL AND NORTHERN ZONES...LIKELY RISING GRADUALLY TOWARD MORNING AS THE WARM FRONT LIFTS NORTH ACROSS AREA. CONSIDERING THE LIGHT WINDS, THIS WILL ALSO BRING WIDESPREAD STRATUS/AREAS OF FOG INLAND EARLY TONIGHT THROUGH EARLY SATURDAY MORNING. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... WEEKEND GETS OFF TO A VERY WET START, WITH HIGH CONFIDENCE OF A STEADY AND LOCALLY HEAVY RAINFALL ON SATURDAY. DEEP MOISTURE THROUGH 300MB COMBINED WITH STRONG LIFT SHOULD PRODUCE MODERATE TO OCCASIONALLY HEAVY RAIN BY AFTN. HOWEVER...QPF SHOULD LARGELY AVG 0.75-1.25" DUE TO THE QUICK MOTION OF THE SYSTEM. TEMPERATURES SHOULD BE VERY MILD, AS THE SURFACE WARM FRONT SURGES N OF THE LOCAL AREA EARLY IN THE DAY. BREEZY CONDITIONS DEVELOP FOR THE EASTERN THIRD OF THE AREA...WITH A S WIND OF 15-20MPH IN THE WARM SECTOR, WITH GUSTS TO AROUND 30MPH EXPECTED. FORECAST HIGHS WILL RANGE FROM THE U50S/L60S IN THE MODIFIED WEDGE AIRMASS ACROSS THE FAR NW TIER...WITH MID 60S TO AROUND 70 OVER THE I-95 CORRIDOR AND THE LOWER EASTERN SHORE...AND LOW 70S ACROSS FAR EASTERN VA AND INTERIOR NE NC. SEE CLIMATE SECTION BELOW...AS A FEW RECORD HIGHS FOR THE DATE APPEAR ATTAINABLE. SREF CONTINUES TO ADVERTISE 90+% CONFIDENCE IN 2M DEWPOINT VALUES AOA 60F ACROSS CENTRAL/EASTERN SECTIONS. THIS COULD LEAD TO ISOLATED THUNDERSTORMS SAT AFTN, PRIMARILY SOUTH AND EAST OF RIC /TRI- CITIES AREA TOWARDS HAMPTON ROADS/TIDEWATER AREAS. GOOD MODEL AGREEMENT IN DEPICTION OF STRONG LIFT (UPRIGHT FRONTOGENESIS) FROM THE SURFACE TO ~850MB ON MODEL CROSS SECTIONS PER THE GFS/NAM SAT AFTN. THIS IS PROGGED TO OCCUR IN A SYNOPTIC ENVIRONMENT FEATURING A 65-70KT LLJ...50-60KT OF SW 0-6KM BULK SHEAR...AND 500-700 J/KG MLCAPE. GIVEN THIS COMBINATION OF SYNOPTIC AND MESOSCALE FACTORS...THERE IS A HIGH CONFIDENCE IN WIDESPREAD MOD RAINFALL (FALLING HEAVILY AT TIMES). HOWEVER, THERE IS ALSO POTENTIAL FOR A FORCED LINE OF LOW-TOPPED CONVECTION (RARE BUT NOT UNPRECEDENTED FOR JANUARY) CAPABLE OF MIXING DOWN SOME STRONG TO POTENTIALLY DAMAGING WIND GUSTS. AREA OF CONCERN REMAINS MAINLY ACROSS THE AFOREMENTIONED AREAS OF S-CENTRAL/SE VA AND NE NC. BASED ON THE LATEST 12Z/10 DATA...THE TIMING OF THE GREATEST THREAT WOULD BE AFTER 18Z/1P SAT AFTERNOON INTO EARLY EVENING. SE PORTIONS OF THE AREA REMAIN HIGHLIGHTED IN A DAY 2 SLIGHT RISK BY THE SPC...AND WILL CONTINUE TO HIGHLIGHT THIS AREA IN THE HWO. A TRANSITION DAY SUNDAY AND EARLY MONDAY AS UPPER TROUGH PIVOTS OFFSHORE AND QUASI-ZONAL FLOW BRINGS A CLEARING SKY. WHILE NOT NEARLY AS MILD AS SATURDAY, MAXIMA REMAIN ~1 S.D. ABOVE NORMAL...CLIMBING INTO THE MID 50S TO NEAR 60 FOR MOST. EARLY MORNING LOWS MONDAY IN THE 30S TO NEAR 40. FLOW ALOFT BECOMES INCREASINGLY SW ON MONDAY...WITH GRADUALLY INCREASING HIGH CLOUDS LATER IN THE DAY AS AN UPPER LEVEL TROUGH BARRELS EASTWARD FROM THE PLAINS MONDAY THROUGH MONDAY NIGHT. ECMWF IS A BIT MORE AGGRESSIVE WITH THIS FEATURE THAN THE GFS. FOR NOW, HAVE PLAYED TOWARDS THE DRIER/WEAKER GFS SOLUTION...WITH WARM SW FLOW ALLOWING MAXIMA TO WARM BACK INTO THE U50S TO L60S. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... MEDIUM RANGE MODELS IN GENERAL AGREEMENT WITH AMPLIFIED...BUT PROGRESSIVE UPPER LEVEL PATTERN THROUGH THE EXTENDED PERIOD. HOWEVER...MODELS CONTINUE TO STRUGGLE WITH MID-LEVEL FEATURES DOWNSTREAM OF A LONGWAVE TROUGH OVER THE ERN CONUS. LONGWAVE TROUGH WILL PROGRESS EWD OVER THE CENTRAL CONUS MON NIGHT-TUES AS SHORTWAVE ENERGY ROUNDS THE BASE OF THE TROUGH AND EJECTS NEWD FROM THE DEEP SOUTH. SHORTWAVE ENERGY WILL EJECT FROM THE DEEP SOUTH TUES MORNING OVER THE MID- ATLANTIC TUES AFTERNOON. ECMWF IS MUCH STRONGER WITH THE SHORTWAVE ENERGY AND SWLY FLOW WHICH WOULD ADVECT DEEPER MOISTURE INTO THE REGION IN ADVANCE OF A COLD FRONT. MEANWHILE...GFS IS MUCH WEAKER WITH THE ENERGY AND HAS LIMITED MOISTURE. SFC PATTERNS ALSO QUITE DIFFERENT AS SFC LOW PRESSURE CROSSES THE OH VALLEY. HAVE TRENDED CURRENT FORECAST TOWARD THE ECMWF...BUT MAINTAINED SOME GFS GUIDANCE TO ACCOUNT FOR UNCERTAINTIES. THE RESULT IS CHANCE POPS ACROSS THE REGION BEGINNING TUES MORNING INTO TUES AFTERNOON AS THE SYSTEM LIFTS OVER THE REGION. COLD FRONT/MOISTURE WILL PUSH OFFSHORE LATE TUES BRINGING AN END TO THE PRECIP. BASE OF THE TROUGH WILL EXTEND INTO THE DEEP SOUTH TUES NIGHT-WEDS MORNING AS AN ASSOCIATED STRONGER COLD FRONT MOVES INTO THE REGION. UPPER DYNAMICS WILL DEVELOP A WAVE ALONG THE FRONT...LEADING TO CYCLOGENESIS OVER THE LOCAL AREA TO JUST OFFSHORE EARLY WEDS. MOISTURE WILL BE RATHER LIMITED/SHALLOW...BUT BASED ON DYNAMICS...SLIGHT CHANCE POPS ARE WARRANTED ATTM. TROUGH AXIS WILL PUSH OFFSHORE WED NIGHT-THURS MORNING AS SFC HIGH PRESSURE BUILDS EWD OVER THE DEEP SOUTH...RIDGING NWD INTO THE LOCAL AREA. NRN STREAM WILL REMAIN ACTIVE AS ANOTHER SHORTWAVE DIGS OVER THE GREAT LAKES REGION LATE THURS-FRI...PUSHING A COLD FRONT ACROSS THE OH VALLEY INTO THE MID-ATLANTIC REGION FRI. UNCERTAINTY IS QUITE HIGH THIS FAR OUT...SO HAVE LEFT THE END OF THE WORK WEEK DRY. HIGH TEMPS WILL WARM ABOVE NORMAL TUES (UPPER 50S-LOW 60S) BEFORE FALLING BACK TO SEASONABLE NORMS THRU THE EXTENDED. MILD MON NIGHT (LOW-MID 40S) BEFORE RETURNING TO NEAR OR SLIGHTLY ABOVE SEASONABLE LOWS (LOW-MID 30S) THRU THE EXTENDED. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... -RA AND BR ACROSS THE AREA WILL CONTINUE THROUGH TONIGHT. SITES NORTH AND WEST OF A WARM FRONT(KRIC AND KSBY) ARE EXPERIENCING IFR CONDITIONS AND WILL CONTINUE TO DO SO UNTIL THE WARM FRONT LIFTS THROUGH THOSE AREAS. EXPECT WINDS TO GUST OVER 20KT SAT AS PRESSURE GRADIENT TIGHTENS BETWEEN APPROACHING TROUGH FROM THE WEST AND HIGH PRESSURE OFFSHORE. SCATTERED SHOWERS ARE POSSIBLE DURING THE LATE MORNING/EARLY AFTN HOURS SAT AS A COLD FRONT PUSHES EAST. OUTLOOK...A MORE ORGANIZED FRONTAL SYSTEM APPROACHES THE REGION ON SATURDAY...WITH PERIODS OF RAIN AND WIDESPREAD MVFR/OCNL IFR CONDITIONS AND GUSTY WINDS SAT AFTN. LOOK FOR DRY AND VFR CONDITIONS SUNDAY AND MONDAY THEN DETERIORATING CONDS ONCE AGAIN AROUND TUESDAY. && .MARINE... HIGH PRESSURE HAS LOCATED OVER THE WRN ATLANTIC THIS AFTERNOON. FLOW WILL TURN TO THE SOUTH AND INCREASE BEHIND A LIFTING WARM FRONT TONIGHT. GRADIENT WILL STRENGTHENS AS LOW PRESSURE AND AN ASSOCIATED COLD FRONT APPROACH FROM THE WEST. LOW-LEVEL WINDS (925MB) WILL INCREASE TO ~50 KT TONIGHT-SAT MORNING...BUT WAA/WEAK LAPSE RATES AND COLD WATERS WILL LIMIT THE HIGHER VELOCITY WINDS FROM REACHING THE WATER. HOWEVER...MODELS IN GOOD AGREEMENT FOR SOLID SCA CONDITIONS TONIGHT-SAT. SEAS WILL BUILD TO 5 TO 9 FT (UP TO 10+ FT 20 NM OUT IN THE NRN COASTAL WATERS). COLD FRONT WILL CROSS THE WATERS LATE SAT-EARLY SAT NIGHT AS WINDS BACK TO THE WEST AND REMAIN 15-20 KT OVER THE BAY/RIVERS AND 20-25 KT OVER THE COASTAL WATERS. A LINE OF CONVECTION IS EXPECTED ALONG THE COLD FRONT LATE SAT...WHICH MAY BRIEFLY PRODUCE GALE FORCE WINDS. HOWEVER...WILL LIKELY HANDLE THESE BRIEF/STRONG WINDS WITH SPECIAL MARINE WARNINGS INSTEAD OF GALE WORDING. HIGH PRESSURE WILL BUILD EWD OVER THE DEEP SOUTH SAT NIGHT-SUN...EXTENDING NWD OVER THE LOCAL AREA LATE SUN MORNING. THIS WILL ALLOW THE GRADIENT TO RELAX AND SPEEDS TO DIMINISH. AS HIGH PRESSURE PUSHES OFF THE SE COAST SUN NIGHT...FLOW WILL RETURN TO THE SOUTH. UNSETTLED CONDITIONS WILL RETURN TO THE WATERS TUES-WEDS. && .CLIMATE... RECORD HIGH TEMPERATURES SATURDAY JANUARY 11 RIC 72/1975 ORF 75/1974 SBY 68/1975 ECG 75/1974 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ635>637. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 10 AM EST SUNDAY FOR ANZ632>634. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ630-631. SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 10 AM EST SUNDAY FOR ANZ638. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 4 PM EST SUNDAY FOR ANZ650-652-654-656-658. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...AJZ/MAM LONG TERM...SAM AVIATION...JDM/DAP MARINE...SAM CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
430 PM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE MOVES OFFSHORE TODAY AND TONIGHT AS A SERIES OF WEAK UPPER LEVEL TROUGHS TRACK ACROSS THE MID ATLANTIC REGION. A COLD FRONT APPROACHES FROM THE WEST SATURDAY AND PUSHES THROUGH THE REGION SATURDAY NIGHT EVENING. HIGH PRESSURE RETURNS FROM THE WEST LATER SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... LATEST SURFACE ANALYSIS INDICATES A ~1034MB SFC HIGH PRESSURE NOW WELL OFF THE NEW ENGLAND COASTLINE...WITH A SFC RIDGE AXIS EXTENDING SW ALONG THE PIEDMONT INTO NE GA. TO THE SOUTHEAST, A COASTAL TROUGH HAS NOW LIFTED INLAND ACROSS THE COASTAL CAROLINAS...AND BRIEFLY LIFTED ACROSS FAR SE TIP OF THE COMMONWEALTH EARLY THIS AFTN (TEMPS JUMPED INTO THE LOW 60S EARLY THIS AFTN BEFORE DROPPING BACK INTO THE U40S OVER THE PAST FEW HRS). WARM/MOIST ADVECTION CONTINUES THIS AFTN...WITH SHRAS IN ASSN WITH THE LATEST SLUG OF OVERRUNNING MOISTURE MOVING ACROSS THE REGION ATTM. WV SAT IMAGERY SHOWING DISTURBANCE RESPONSIBLE FOR THIS LATEST ROUND OF SHRAS LIFTING E-NE ACROSS THE LOWER MID- ATLANTIC IN SSW FLOW ALOFT. OCCASIONAL LIGHT RAINFALL WILL CONTINUE OVER THE NEXT FEW HOURS AS THIS WAVE MOVES THROUGH...WITH SHRAS BECOMING LESS WIDESPREAD LATE TONIGHT AND ESPECIALLY AFTER MIDNIGHT AS FRONT SHIFTS NORTH. FOR TEMPS, WE`VE FOLLOWED THE LEAD OF THE HRRR AND HIGH RES NAM W/TEMP TRENDS THROUGH EARLY SAT MORNING. EXPECT TEMPS WILL FALL VERY LITTLE EARLY TONIGHT ACROSS CENTRAL AND NORTHERN ZONES...LIKELY RISING GRADUALLY TOWARD MORNING AS THE WARM FRONT LIFTS NORTH ACROSS AREA. CONSIDERING THE LIGHT WINDS, THIS WILL ALSO BRING WIDESPREAD STRATUS/AREAS OF FOG INLAND EARLY TONIGHT THROUGH EARLY SATURDAY MORNING. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/... WEEKEND GETS OFF TO A VERY WET START, WITH HIGH CONFIDENCE OF A STEADY AND LOCALLY HEAVY RAINFALL ON SATURDAY. DEEP MOISTURE THROUGH 300MB COMBINED WITH STRONG LIFT SHOULD PRODUCE MODERATE TO OCCASIONALLY HEAVY RAIN BY AFTN. HOWEVER...QPF SHOULD LARGELY AVG 0.75-1.25" DUE TO THE QUICK MOTION OF THE SYSTEM. TEMPERATURES SHOULD BE VERY MILD, AS THE SURFACE WARM FRONT SURGES N OF THE LOCAL AREA EARLY IN THE DAY. BREEZY CONDITIONS DEVELOP FOR THE EASTERN THIRD OF THE AREA...WITH A S WIND OF 15-20MPH IN THE WARM SECTOR, WITH GUSTS TO AROUND 30MPH EXPECTED. FORECAST HIGHS WILL RANGE FROM THE U50S/L60S IN THE MODIFIED WEDGE AIRMASS ACROSS THE FAR NW TIER...WITH MID 60S TO AROUND 70 OVER THE I-95 CORRIDOR AND THE LOWER EASTERN SHORE...AND LOW 70S ACROSS FAR EASTERN VA AND INTERIOR NE NC. SEE CLIMATE SECTION BELOW...AS A FEW RECORD HIGHS FOR THE DATE APPEAR ATTAINABLE. SREF CONTINUES TO ADVERTISE 90+% CONFIDENCE IN 2M DEWPOINT VALUES AOA 60F ACROSS CENTRAL/EASTERN SECTIONS. THIS COULD LEAD TO ISOLATED THUNDERSTORMS SAT AFTN, PRIMARILY SOUTH AND EAST OF RIC /TRI- CITIES AREA TOWARDS HAMPTON ROADS/TIDEWATER AREAS. GOOD MODEL AGREEMENT IN DEPICTION OF STRONG LIFT (UPRIGHT FRONTOGENESIS) FROM THE SURFACE TO ~850MB ON MODEL CROSS SECTIONS PER THE GFS/NAM SAT AFTN. THIS IS PROGGED TO OCCUR IN A SYNOPTIC ENVIRONMENT FEATURING A 65-70KT LLJ...50-60KT OF SW 0-6KM BULK SHEAR...AND 500-700 J/KG MLCAPE. GIVEN THIS COMBINATION OF SYNOPTIC AND MESOSCALE FACTORS...THERE IS A HIGH CONFIDENCE IN WIDESPREAD MOD RAINFALL (FALLING HEAVILY AT TIMES). HOWEVER, THERE IS ALSO POTENTIAL FOR A FORCED LINE OF LOW-TOPPED CONVECTION (RARE BUT NOT UNPRECEDENTED FOR JANUARY) CAPABLE OF MIXING DOWN SOME STRONG TO POTENTIALLY DAMAGING WIND GUSTS. AREA OF CONCERN REMAINS MAINLY ACROSS THE AFOREMENTIONED AREAS OF S-CENTRAL/SE VA AND NE NC. BASED ON THE LATEST 12Z/10 DATA...THE TIMING OF THE GREATEST THREAT WOULD BE AFTER 18Z/1P SAT AFTERNOON INTO EARLY EVENING. SE PORTIONS OF THE AREA REMAIN HIGHLIGHTED IN A DAY 2 SLIGHT RISK BY THE SPC...AND WILL CONTINUE TO HIGHLIGHT THIS AREA IN THE HWO. A TRANSITION DAY SUNDAY AND EARLY MONDAY AS UPPER TROUGH PIVOTS OFFSHORE AND QUASI-ZONAL FLOW BRINGS A CLEARING SKY. WHILE NOT NEARLY AS MILD AS SATURDAY, MAXIMA REMAIN ~1 S.D. ABOVE NORMAL...CLIMBING INTO THE MID 50S TO NEAR 60 FOR MOST. EARLY MORNING LOWS MONDAY IN THE 30S TO NEAR 40. FLOW ALOFT BECOMES INCREASINGLY SW ON MONDAY...WITH GRADUALLY INCREASING HIGH CLOUDS LATER IN THE DAY AS AN UPPER LEVEL TROUGH BARRELS EASTWARD FROM THE PLAINS MONDAY THROUGH MONDAY NIGHT. ECMWF IS A BIT MORE AGGRESSIVE WITH THIS FEATURE THAN THE GFS. FOR NOW, HAVE PLAYED TOWARDS THE DRIER/WEAKER GFS SOLUTION...WITH WARM SW FLOW ALLOWING MAXIMA TO WARM BACK INTO THE U50S TO L60S. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... MEDIUM RANGE MODELS IN GENERAL AGREEMENT WITH AMPLIFIED...BUT PROGRESSIVE UPPER LEVEL PATTERN THROUGH THE EXTENDED PERIOD. HOWEVER...MODELS CONTINUE TO STRUGGLE WITH MID-LEVEL FEATURES DOWNSTREAM OF A LONGWAVE TROUGH OVER THE ERN CONUS. LONGWAVE TROUGH WILL PROGRESS EWD OVER THE CENTRAL CONUS MON NIGHT-TUES AS SHORTWAVE ENERGY ROUNDS THE BASE OF THE TROUGH AND EJECTS NEWD FROM THE DEEP SOUTH. SHORTWAVE ENERGY WILL EJECT FROM THE DEEP SOUTH TUES MORNING OVER THE MID-ATLANTIC TUES AFTERNOON. ECMWF IS MUCH STRONGER WITH THE SHORTWAVE ENERGY AND SWLY FLOW WHICH WOULD ADVECT DEEPER MOISTURE INTO THE REGION IN ADVANCE OF A COLD FRONT. MEANWHILE...GFS IS MUCH WEAKER WITH THE ENERGY AND HAS LIMITED MOISTURE. SFC PATTERNS ALSO QUITE DIFFERENT AS SFC LOW PRESSURE CROSSES THE OH VALLEY. HAVE TRENDED CURRENT FORECAST TOWARD THE ECMWF...BUT MAINTAINED SOME GFS GUIDANCE TO ACCOUNT FOR UNCERTAINTIES. THE RESULT IS CHANCE POPS ACROSS THE REGION BEGINNING TUES MORNING INTO TUES AFTERNOON AS THE SYSTEM LIFTS OVER THE REGION. COLD FRONT/MOISTURE WILL PUSH OFFSHORE LATE TUES BRINGING AN END TO THE PRECIP. BASE OF THE TROUGH WILL EXTEND INTO THE DEEP SOUTH TUES NIGHT-WEDS MORNING AS AN ASSOCIATED STRONGER COLD FRONT MOVES INTO THE REGION. UPPER DYNAMICS WILL DEVELOP A WAVE ALONG THE FRONT...LEADING TO CYCLOGENESIS OVER THE LOCAL AREA TO JUST OFFSHORE EARLY WEDS. MOISTURE WILL BE RATHER LIMITED/SHALLOW...BUT BASED ON DYNAMICS...SLIGHT CHANCE POPS ARE WARRANTED ATTM. TROUGH AXIS WILL PUSH OFFSHORE WED NIGHT-THURS MORNING AS SFC HIGH PRESSURE BUILDS EWD OVER THE DEEP SOUTH...RIDGING NWD INTO THE LOCAL AREA. NRN STREAM WILL REMAIN ACTIVE AS ANOTHER SHORTWAVE DIGS OVER THE GREAT LAKES REGION LATE THURS-FRI...PUSHING A COLD FRONT ACROSS THE OH VALLEY INTO THE MID-ATLANTIC REGION FRI. UNCERTAINTY IS QUITE HIGH THIS FAR OUT...SO HAVE LEFT THE END OF THE WORK WEEK DRY. HIGH TEMPS WILL WARM ABOVE NORMAL TUES (UPPER 50S-LOW 60S) BEFORE FALLING BACK TO SEASONABLE NORMS THRU THE EXTENDED. MILD MON NIGHT (LOW-MID 40S) BEFORE RETURNING TO NEAR OR SLIGHTLY ABOVE SEASONABLE LOWS (LOW-MID 30S) THRU THE EXTENDED. && .AVIATION /22Z FRIDAY THROUGH WEDNESDAY/... -RA AND BR ACROSS THE AREA WILL CONTINUE THROUGH TONIGHT. SITES NORTH AND WEST OF A WARM FRONT(KRIC AND KSBY) ARE EXPERIENCING IFR CONDITIONS AND WILL CONTINUE TO DO SO UNTIL THE WARM FRONT LIFTS THROUGH THOSE AREAS. EXPECT WINDS TO GUST OVER 20KT SAT AS PRESSURE GRADIENT TIGHTENS BETWEEN APPROACHING TROUGH FROM THE WEST AND HIGH PRESSURE OFFSHORE. SCATTERED SHOWERS ARE POSSIBLE DURING THE LATE MORNING/EARLY AFTN HOURS SAT AS A COLD FRONT PUSHES EAST. OUTLOOK...A MORE ORGANIZED FRONTAL SYSTEM APPROACHES THE REGION ON SATURDAY...WITH PERIODS OF RAIN AND WIDESPREAD MVFR/OCNL IFR CONDITIONS AND GUSTY WINDS SAT AFTN. LOOK FOR DRY AND VFR CONDITIONS SUNDAY AND MONDAY THEN DETERIORATING CONDS ONCE AGAIN AROUND TUESDAY. && .MARINE... HIGH PRESSURE MOVES OFF THE NEW ENGLAND COAST TODAY...AS A TROF OF LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST. E WINDS 10 KT OR LESS THIS MORNING WILL BECOME SE 10-15 KT BY EVENING. SE WINDS WILL THEN INCREASE TO 15 TO 20 KT LATE TONIGHT BEFORE BECOME S AND INCREASING TO 15 TO 25 KT AND GUSTY FOR SAT...AS A WARM FRONT LIFTS NWRD THRU THE AREA...FOLLOWED BY THE APPROACH OF A COLD FRONT. HAVE ISSUED SCA`S BEGINNING EARLY SAT MORNING FOR ALL WATERS BASED ON GOOD AGREEMENT IN MODELS FOR GUSTY WINDS DURING SAT INTO SAT NIGHT... ALONG WITH SEAS BUILDING TO 5-9 FT. GALE FORCE WINDS ARE NOT EXPECTED ATTM EXCEPT POSSIBLY IN A NARROW BAND OF CONVECTION THAT MAY MOVE THRU WITH THE COLD FRONT LATE SAT. THIS CAN LIKELY BE HANDLED WITH SPECIAL MARINE WARNINGS AS OPPOSED TO A SHORT DURATION GALE WARNING. S-SW WINDS SAT INTO SAT EVE WILL VEER TO THE WNW AND REMAIN GUSTY BEHIND THE FRONT SAT NIGHT INTO SUN MORNING...THEN SETTLE DOWN AND BECOME SW LATE SUNDAY AS HIGH PRESSURE BUILDS IN. ANOTHER ROUND OF UNSETTLED CONDITIONS IS POSSIBLE BY TUESDAY. && .CLIMATE... RECORD HIGH TEMPERATURES SATURDAY JANUARY 11 RIC 72/1975 ORF 75/1974 SBY 68/1975 ECG 75/1974 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ635>637. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 10 AM EST SUNDAY FOR ANZ632>634. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ630-631. SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 10 AM EST SUNDAY FOR ANZ638. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 4 PM EST SUNDAY FOR ANZ650-652-654-656-658. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...AJZ/MAM LONG TERM...SAM AVIATION...JDM/DAP MARINE...JDM CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
411 PM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE MOVES OFFSHORE TODAY AND TONIGHT AS A SERIES OF WEAK UPPER LEVEL TROUGHS TRACK ACROSS THE MID ATLANTIC REGION. A COLD FRONT APPROACHES FROM THE WEST SATURDAY AND PUSHES THROUGH THE REGION SATURDAY NIGHT EVENING. HIGH PRESSURE RETURNS FROM THE WEST LATER SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... LATEST SURFACE ANALYSIS INDICATES A ~1034MB SFC HIGH PRESSURE NOW WELL OFF THE NEW ENGLAND COASTLINE...WITH A SFC RIDGE AXIS EXTENDING SW ALONG THE PIEDMONT INTO NE GA. TO THE SOUTHEAST, A COASTAL TROUGH HAS NOW LIFTED INLAND ACROSS THE COASTAL CAROLINAS...AND BRIEFLY LIFTED ACROSS FAR SE TIP OF THE COMMONWEALTH EARLY THIS AFTN (TEMPS JUMPED INTO THE LOW 60S EARLY THIS AFTN BEFORE DROPPING BACK INTO THE U40S OVER THE PAST FEW HRS). WARM/MOIST ADVECTION CONTINUES THIS AFTN...WITH SHRAS IN ASSN WITH THE LATEST SLUG OF OVERRUNNING MOISTURE MOVING ACROSS THE REGION ATTM. WV SAT IMAGERY SHOWING DISTURBANCE RESPONSIBLE FOR THIS LATEST ROUND OF SHRAS LIFTING E-NE ACROSS THE LOWER MID- ATLANTIC IN SSW FLOW ALOFT. OCCASIONAL LIGHT RAINFALL WILL CONTINUE OVER THE NEXT FEW HOURS AS THIS WAVE MOVES THROUGH...WITH SHRAS BECOMING LESS WIDESPREAD LATE TONIGHT AND ESPECIALLY AFTER MIDNIGHT AS FRONT SHIFTS NORTH. FOR TEMPS, WE`VE FOLLOWED THE LEAD OF THE HRRR AND HIGH RES NAM W/TEMP TRENDS THROUGH EARLY SAT MORNING. EXPECT TEMPS WILL FALL VERY LITTLE EARLY TONIGHT ACROSS CENTRAL AND NORTHERN ZONES...LIKELY RISING GRADUALLY TOWARD MORNING AS THE WARM FRONT LIFTS NORTH ACROSS AREA. CONSIDERING THE LIGHT WINDS, THIS WILL ALSO BRING WIDESPREAD STRATUS/AREAS OF FOG INLAND EARLY TONIGHT THROUGH EARLY SATURDAY MORNING. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/... WEEKEND GETS OFF TO A VERY WET START, WITH HIGH CONFIDENCE OF A STEADY AND LOCALLY HEAVY RAINFALL ON SATURDAY. DEEP MOISTURE THROUGH 300MB COMBINED WITH STRONG LIFT SHOULD PRODUCE MODERATE TO OCCASIONALLY HEAVY RAIN BY AFTN. HOWEVER...QPF SHOULD LARGELY AVG 0.75-1.00IN DUE TO THE QUICK MOTION OF THE SYSTEM. TEMPERATURES SHOULD BE VERY MILD, AS THE SURFACE WARM FRONT SURGES N OF THE LOCAL AREA EARLY IN THE DAY. BREEZY CONDITIONS DEVELOP FOR THE EASTERN THIRD OF THE AREA...WITH A S WIND OF 15-20MPH IN THE WARM SECTOR, WITH GUSTS TO AROUND 30MPH EXPECTED. FORECAST HIGHS WILL RANGE FROM THE U50S/L60S IN THE MODIFIED WEDGE AIRMASS ACROSS THE FAR NW TIER...WITH MID 60S TO AROUND 70 OVER THE I-95 CORRIDOR AND THE LOWER EASTERN SHORE...AND LOW 70S ACROSS FAR EASTERN VA AND INTERIOR NE NC. SEE CLIMATE SECTION BELOW...AS A FEW RECORD HIGHS FOR THE DATE APPEAR ATTAINABLE. SREF CONTINUES TO ADVERTISE 90+% CONFIDENCE IN 2M DEWPOINT VALUES AOA 60F ACROSS CENTRAL/EASTERN SECTIONS. THIS COULD LEAD TO ISOLATED THUNDERSTORMS SAT AFTN, PRIMARILY SOUTH AND EAST OF RIC /TRI- CITIES AREA TOWARDS HAMPTON ROADS/TIDEWATER AREAS. GOOD MODEL AGREEMENT IN DEPICTION OF STRONG LIFT (UPRIGHT FRONTOGENESIS) FROM THE SURFACE TO ~850MB ON MODEL CROSS SECTIONS PER THE GFS/NAM SAT AFTN. THIS IS PROGGED TO OCCUR IN A SYNOPTIC ENVIRONMENT FEATURING A 65-70KT LLJ...50-60KT OF SW 0-6KM BULK SHEAR...AND 500-700 J/KG MLCAPE. GIVEN THIS COMBINATION OF SYNOPTIC AND MESOSCALE FACTORS...THERE IS A HIGH CONFIDENCE IN WIDESPREAD MOD RAINFALL (FALLING HEAVILY AT TIMES). HOWEVER, THERE IS ALSO POTENTIAL FOR A FORCED LINE OF LOW-TOPPED CONVECTION (RARE BUT NOT UNPRECEDENTED FOR JANUARY) CAPABLE OF MIXING DOWN SOME STRONG TO POTENTIALLY DAMAGING WIND GUSTS. AREA OF CONCERN REMAINS MAINLY ACROSS THE AFOREMENTIONED AREAS OF S-CENTRAL/SE VA AND NE NC. BASED ON THE LATEST 12Z/10 DATA...THE TIMING OF THE GREATEST THREAT WOULD BE AFTER 18Z/1P SAT AFTERNOON INTO EARLY EVENING. SE PORTIONS OF THE AREA REMAIN HIGHLIGHTED IN A DAY 2 SLIGHT RISK BY THE SPC...AND WILL CONTINUE TO HIGHLIGHT THIS AREA IN THE HWO. A TRANSITION DAY SUNDAY AND EARLY MONDAY AS UPPER TROUGH PIVOTS OFFSHORE AND QUASI-ZONAL FLOW BRINGS A CLEARING SKY. WHILE NOT NEARLY AS MILD AS SATURDAY, MAXIMA REMAIN ~1 S.D. ABOVE NORMAL...CLIMBING INTO THE MID 50S TO NEAR 60 FOR MOST. EARLY MORNING LOWS MONDAY IN THE 30S TO NEAR 40. FLOW ALOFT BECOMES INCREASINGLY SW ON MONDAY...WITH GRADUALLY INCREASING HIGH CLOUDS LATER IN THE DAY AS AN UPPER LEVEL TROUGH BARRELS EASTWARD FROM THE PLAINS MONDAY THROUGH MONDAY NIGHT. ECMWF IS A BIT MORE AGGRESSIVE WITH THIS FEATURE THAN THE GFS. FOR NOW, HAVE PLAYED TOWARDS THE DRIER/WEAKER GFS SOLUTION...WITH WARM SW FLOW ALLOWING MAXIMA TO WARM BACK INTO THE U50S TO L60S. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... MEDIUM RANGE MODELS IN GENERAL AGREEMENT WITH AMPLIFIED...BUT PROGRESSIVE UPPER LEVEL PATTERN THROUGH THE EXTENDED PERIOD. HOWEVER...MODELS CONTINUE TO STRUGGLE WITH MID-LEVEL FEATURES DOWNSTREAM OF A LONGWAVE TROUGH OVER THE ERN CONUS. LONGWAVE TROUGH WILL PROGRESS EWD OVER THE CENTRAL CONUS MON NIGHT-TUES AS SHORTWAVE ENERGY ROUNDS THE BASE OF THE TROUGH AND EJECTS NEWD FROM THE DEEP SOUTH. SHORTWAVE ENERGY WILL EJECT FROM THE DEEP SOUTH TUES MORNING OVER THE MID-ATLANTIC TUES AFTERNOON. ECMWF IS MUCH STRONGER WITH THE SHORTWAVE ENERGY AND SWLY FLOW WHICH WOULD ADVECT DEEPER MOISTURE INTO THE REGION IN ADVANCE OF A COLD FRONT. MEANWHILE...GFS IS MUCH WEAKER WITH THE ENERGY AND HAS LIMITED MOISTURE. SFC PATTERNS ALSO QUITE DIFFERENT AS SFC LOW PRESSURE CROSSES THE OH VALLEY. HAVE TRENDED CURRENT FORECAST TOWARD THE ECMWF...BUT MAINTAINED SOME GFS GUIDANCE TO ACCOUNT FOR UNCERTAINTIES. THE RESULT IS CHANCE POPS ACROSS THE REGION BEGINNING TUES MORNING INTO TUES AFTERNOON AS THE SYSTEM LIFTS OVER THE REGION. COLD FRONT/MOISTURE WILL PUSH OFFSHORE LATE TUES BRINGING AN END TO THE PRECIP. BASE OF THE TROUGH WILL EXTEND INTO THE DEEP SOUTH TUES NIGHT-WEDS MORNING AS AN ASSOCIATED STRONGER COLD FRONT MOVES INTO THE REGION. UPPER DYNAMICS WILL DEVELOP A WAVE ALONG THE FRONT...LEADING TO CYCLOGENESIS OVER THE LOCAL AREA TO JUST OFFSHORE EARLY WEDS. MOISTURE WILL BE RATHER LIMITED/SHALLOW...BUT BASED ON DYNAMICS...SLIGHT CHANCE POPS ARE WARRANTED ATTM. TROUGH AXIS WILL PUSH OFFSHORE WED NIGHT-THURS MORNING AS SFC HIGH PRESSURE BUILDS EWD OVER THE DEEP SOUTH...RIDGING NWD INTO THE LOCAL AREA. NRN STREAM WILL REMAIN ACTIVE AS ANOTHER SHORTWAVE DIGS OVER THE GREAT LAKES REGION LATE THURS-FRI...PUSHING A COLD FRONT ACROSS THE OH VALLEY INTO THE MID-ATLANTIC REGION FRI. UNCERTAINTY IS QUITE HIGH THIS FAR OUT...SO HAVE LEFT THE END OF THE WORK WEEK DRY. HIGH TEMPS WILL WARM ABOVE NORMAL TUES (UPPER 50S-LOW 60S) BEFORE FALLING BACK TO SEASONABLE NORMS THRU THE EXTENDED. MILD MON NIGHT (LOW-MID 40S) BEFORE RETURNING TO NEAR OR SLIGHTLY ABOVE SEASONABLE LOWS (LOW-MID 30S) THRU THE EXTENDED. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... -RA AND BR ACROSS THE AREA WILL CONTINUE THROUGH TONIGHT. SITES NORTH AND WEST OF A WARM FRONT(KRIC AND KSBY) ARE EXPERIENCING IFR CONDITIONS AND WILL CONTINUE TO DO SO UNTIL THE WARM FRONT LIFTS THROUGH THOSE AREAS. EXPECT WINDS TO GUST OVER 20KT SAT AS PRESSURE GRADIENT TIGHTENS BETWEEN APPROACHING TROUGH FROM THE WEST AND HIGH PRESSURE OFFSHORE. SCATTERED SHOWERS ARE POSSIBLE DURING THE LATE MORNING/EARLY AFTN HOURS SAT AS A COLD FRONT PUSHES EAST. OUTLOOK...A MORE ORGANIZED FRONTAL SYSTEM APPROACHES THE REGION ON SATURDAY...WITH PERIODS OF RAIN AND WIDESPREAD MVFR/OCNL IFR CONDITIONS AND GUSTY WINDS SAT AFTN. LOOK FOR DRY AND VFR CONDITIONS SUNDAY AND MONDAY THEN DETERIORATING CONDS ONCE AGAIN AROUND TUESDAY. && .MARINE... HIGH PRESSURE MOVES OFF THE NEW ENGLAND COAST TODAY...AS A TROF OF LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST. E WINDS 10 KT OR LESS THIS MORNING WILL BECOME SE 10-15 KT BY EVENING. SE WINDS WILL THEN INCREASE TO 15 TO 20 KT LATE TONIGHT BEFORE BECOME S AND INCREASING TO 15 TO 25 KT AND GUSTY FOR SAT...AS A WARM FRONT LIFTS NWRD THRU THE AREA...FOLLOWED BY THE APPROACH OF A COLD FRONT. HAVE ISSUED SCA`S BEGINNING EARLY SAT MORNING FOR ALL WATERS BASED ON GOOD AGREEMENT IN MODELS FOR GUSTY WINDS DURING SAT INTO SAT NIGHT... ALONG WITH SEAS BUILDING TO 5-9 FT. GALE FORCE WINDS ARE NOT EXPECTED ATTM EXCEPT POSSIBLY IN A NARROW BAND OF CONVECTION THAT MAY MOVE THRU WITH THE COLD FRONT LATE SAT. THIS CAN LIKELY BE HANDLED WITH SPECIAL MARINE WARNINGS AS OPPOSED TO A SHORT DURATION GALE WARNING. S-SW WINDS SAT INTO SAT EVE WILL VEER TO THE WNW AND REMAIN GUSTY BEHIND THE FRONT SAT NIGHT INTO SUN MORNING...THEN SETTLE DOWN AND BECOME SW LATE SUNDAY AS HIGH PRESSURE BUILDS IN. ANOTHER ROUND OF UNSETTLED CONDITIONS IS POSSIBLE BY TUESDAY. && .CLIMATE... RECORD HIGH TEMPERATURES SATURDAY JANUARY 11 RIC 72/1975 ORF 75/1974 SBY 68/1975 ECG 75/1974 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ635>637. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 10 AM EST SUNDAY FOR ANZ632>634. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ630-631. SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 10 AM EST SUNDAY FOR ANZ638. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 4 PM EST SUNDAY FOR ANZ650-652-654-656-658. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...AJZ/MAM LONG TERM...SAM AVIATION...JDM/DAP MARINE...JDM CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
140 PM EST FRI JAN 10 2014 .SYNOPSIS... HIGH PRESSURE MOVES OFFSHORE TODAY AND TONIGHT AS A SERIES OF WEAK UPPER LEVEL TROUGHS TRACK ACROSS THE MID ATLANTIC REGION. A COLD FRONT APPROACHES FROM THE WEST SATURDAY AND PUSHES THROUGH THE REGION SATURDAY NIGHT EVENING. HIGH PRESSURE RETURNS FROM THE WEST LATER SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... QUICK UPDATE TO REFLECT EXPIRATION OF FZRA ADVISORY. WHILE AWOS/MESONET DATA REFLECT THAT TEMPS ARE AOA32 DEG ACROSS THE AREA, WE HAVE HAD SEVERAL REPORTS OF LIGHT FZRA/ICY ROAD CONDITIONS FROM EARLIER THIS MORNING ACROSS THE NOW EXPIRED ADVY AREA. DID ISSUE AN SPS TO REFLECT SOME LINGERING ICY PATCHES ACROSS THIS SAME AREA NW OF RIC METRO THROUGH LATE MORNING. OTHERWISE...NO CHANGES NEEDED ATTM. UPDATED PREV DISCUSSION...ISSUED 718 AM EST THE LATEST SURFACE ANALYSIS INDICATES A ~1036MB SFC HIGH PRESSURE CENTERED OFF CAPE COD...WITH A SFC RIDGE AXIS EXTENDING SW ALONG THE PIEDMONT INTO NE GA...AND A COASTAL TROUGH NOW PRESENT OVER THE NC COASTAL PLAIN INTO SE VA. THE LATEST REGIONAL RADAR MOSAIC INDICATES AN AREA OF WARM ADVECTION EXTENDING FROM THE SOUTHERN APPALACHIANS TO THE MID ATLANTIC. THE HRRR AND RUC BOTH SHOW MOISTURE CONTINUING TO STREAM OVER THE AREA THROUGH THE DAY. WARM/MOIST ADVECTION CONTINUES TODAY. THE SHORTWAVE TROUGH RESPONSIBLE FOR THE MORNING PRECIP LIFTS TO THE NE THIS MORNING. HOWEVER...ANOTHER MID-LEVEL WAVE LIFTS ACROSS THE REGION IN SSW FLOW ALOFT THIS AFTERNOON. THIS WILL BRING ANOTHER ROUND OF RA TO PRIMARILY CENTRAL PORTIONS OF THE AREA LATER THIS AFTERNOON. HIGH TEMPERATURES WILL VARY FROM AROUND 40 NW TODAY WITH A CAD WEDGE IN PLACE...TO NEAR 60 SE AS THE COASTAL FRONT MOVES INLAND. WEAK FLOW AND ABUNDANT MOISTURE BELOW 700MB WILL RESULT IN OVERCAST CONDITIONS THROUGHOUT TODAY. TEMPERATURES SHOULD FALL VERY LITTLE TONIGHT (AND LIKELY RISE TOWARD SATURDAY MORNING) AS THE SURFACE WARM FRONT LIFTS THROUGH THE AREA...RESULTING IN WIDESPREAD STRATUS AND OCCASIONAL -RA/DZ. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... THE TROUGH PRESENTLY DIGGING FROM THE INTERMOUNTAIN WEST TOWARD THE HIGH PLAINS PER GOES WATER VAPOR IMAGERY WILL CONTINUE TO AMPLIFY ACROSS THE CENTRAL CONUS TODAY. INCREASINGLY ZONAL FLOW OVER THE WESTERN US EVENTUALLY PUSHES THE TROUGH AXIS ACROSS THE APPALACHIANS BY SAT/SAT EVENING. ASIDE FROM SUBTLE TIMING DIFFERENCES...GEFS/SREF ENSEMBLE GUIDANCE ALONG WITH DETERMINISTIC ECMWF/GFS/NAM/CMC NOW DEMONSTRATE DECENT AGREEMENT WITH THIS SYSTEM. THERE IS A HIGH CONFIDENCE OF MEASURABLE RAIN IN THE SAT/SAT EVENING TIMEFRAME. DEEP MOISTURE THROUGH 300MB COMBINED WITH STRONG LIFT SHOULD PRODUCE MODERATE TO OCCASIONALLY HEAVY RA. HOWEVER...QPF SHOULD LARGELY AVG 0.75-1.00IN DUE TO THE QUICK MOTION OF THE SYSTEM. TEMPERATURES SHOULD BE VERY MILD AS THE SURFACE WARM FRONT LIFTS N OF THE LOCAL AREA AND 850MB TEMPERATURE SURGE TO 10-12C. FORECAST HIGHS FROM THE MID 60S TO AROUND 70 WILL BE MAINTAINED FOR MUCH OF THE FORECAST AREA. THERE IS STILL SOME UNCERTAINTY WITH RESPECT TO TEMPERATURE OVER NW PORTIONS...AS THERE IS A POSSIBILITY THAT A MODIFIED WEDGE AIRMASS MAY REMAIN LOCKED IN...WHICH COULD KEEP HIGHS IN THE 50S. BREEZY CONDITIONS DEVELOP FOR THE EASTERN THIRD OF THE AREA...WITH A S WIND OF 15-20MPH WITH GUSTS TO AROUND 30MPH. 10/03Z SREF PROBS CONTINUE TO INDICATE A 90% CHANCE OF 2M DEWPOINTS EXCEEDING 60F ACROSS S-CENTRAL/SE VA AND NE NC...AND 10/00Z NAM INDICATES STRONG UPRIGHT FRONTOGENESIS FROM THE SURFACE TO ~850MB...WHICH ENHANCES LOW-LEVEL VERTICAL ASCENT. THIS IS PROGGED TO OCCUR IN A SYNOPTIC ENVIRONMENT FEATURING 65-70KT 850-700MB LAYER AVG SSW WIND...50-60KT OF SW 0-6KM BULK SHEAR...AND 250-500 J/KG ML CAPE. GIVEN THE COMBINATION OF SYNOPTIC AND MESOSCALE FACTORS...THERE IS AN INCREASING PROB FOR A FORCED LINE OF CONVECTION (RARE BUT NOT UNPRECEDENTED FOR JAN) CAPABLE OF PRODUCING STRONG TO POTENTIALLY DAMAGING WIND GUSTS...MAINLY ACROSS S-CENTRAL/SE VA AND NE NC. BASED ON THE LATEST DATA...THE TIMING OF THE GREATEST THREAT WOULD BE FROM SAT AFTERNOON INTO EARLY EVENING. A TRANSITION DAY ON SUNDAY AS UPPER TROUGH PIVOTS OFFSHORE AND QUASI-ZONAL FLOW BRING A CLEARING AND STILL-MILD DAY. HIGHS GENERALLY IN THE 50S TO NEAR 60. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... STAYING CLOSE TO THE 12Z ECMWF FOR THE EXTENDED PERIOD. HI PRES WILL SLIDE OFF THE CST AND OUT TO SEA SUN NGT THRU MON...PROVIDING MSTLY CLEAR/PARTLY TO MOSTLY SUNNY CONDITIONS ACRS THE AREA. LATE MON NGT THRU TUE...THE LATEST ECMWF BRINGS A SRN STREAM LO AND A COLD FRONT TWD/AND ACRS THE AREA LATE MON NGT THRU TUE. AT THIS TIME...HAVE SLGT CHC (20) POPS THEN CHC (30) POPS OVR THE REGION. THE FRONT PUSHES OUT TO SEA TUE EVENG...BUT A SECONDARY BOUNDARY MAY CROSS THE AREA ON WED. HAVE KEPT A DRY FCST FOR WED AT THIS TIME. DRIER AND COOLER WNW FLO FILTERS IN FOR WED NGT THRU THU...AS HI PRES BLDS INTO AND OVR THE REGION. MIN TEMPS WILL RANGE THRU THE 30S MON MORNG...IN THE UPR 30S TO MID 40S TUE MORNG...IN THE 30S WED MORNG...AND IN THE MID 20S TO LWR 30S THU MORNG. MAX TEMPS WILL RANGE FM THE MID 50S TO LWR 60S MON...IN THE 50S TUE...IN THE MID 40S TO LWR 50S WED...AND IN THE 40S THU. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... -RA AND BR ACROSS THE AREA WILL CONTINUE THROUGH TONIGHT. SITES NORTH AND WEST OF A WARM FRONT(KRIC AND KSBY) ARE EXPERIENCING IFR CONDITIONS AND WILL CONTINUE TO DO SO UNTIL THE WARM FRONT LIFTS THROUGH THOSE AREAS. EXPECT WINDS TO GUST OVER 20KT SAT AS PRESSURE GRADIENT TIGHTENS BETWEEN APPROACHING TROUGH FROM THE WEST AND HIGH PRESSURE OFFSHORE. SCATTERED SHOWERS ARE POSSIBLE DURING THE LATE MORNING/EARLY AFTN HOURS SAT AS A COLD FRONT PUSHES EAST. OUTLOOK...A MORE ORGANIZED FRONTAL SYSTEM APPROACHES THE REGION ON SATURDAY...WITH PERIODS OF RAIN AND WIDESPREAD MVFR/OCNL IFR CONDITIONS AND GUSTY WINDS SAT AFTN. LOOK FOR DRY AND VFR CONDITIONS SUNDAY AND MONDAY THEN DETERIORATING CONDS ONCE AGAIN AROUND TUESDAY. && .MARINE... HIGH PRESSURE MOVES OFF THE NEW ENGLAND COAST TODAY...AS A TROF OF LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST. E WINDS 10 KT OR LESS THIS MORNING WILL BECOME SE 10-15 KT BY EVENING. SE WINDS WILL THEN INCREASE TO 15 TO 20 KT LATE TONIGHT BEFORE BECOME S AND INCREASING TO 15 TO 25 KT AND GUSTY FOR SAT...AS A WARM FRONT LIFTS NWRD THRU THE AREA...FOLLOWED BY THE APPROACH OF A COLD FRONT. HAVE ISSUED SCA`S BEGINNING EARLY SAT MORNING FOR ALL WATERS BASED ON GOOD AGREEMENT IN MODELS FOR GUSTY WINDS DURING SAT INTO SAT NIGHT... ALONG WITH SEAS BUILDING TO 5-9 FT. GALE FORCE WINDS ARE NOT EXPECTED ATTM EXCEPT POSSIBLY IN A NARROW BAND OF CONVECTION THAT MAY MOVE THRU WITH THE COLD FRONT LATE SAT. THIS CAN LIKELY BE HANDLED WITH SPECIAL MARINE WARNINGS AS OPPOSED TO A SHORT DURATION GALE WARNING. S-SW WINDS SAT INTO SAT EVE WILL VEER TO THE WNW AND REMAIN GUSTY BEHIND THE FRONT SAT NIGHT INTO SUN MORNING...THEN SETTLE DOWN AND BECOME SW LATE SUNDAY AS HIGH PRESSURE BUILDS IN. ANOTHER ROUND OF UNSETTLED CONDITIONS IS POSSIBLE BY TUESDAY. && .CLIMATE... RECORD HIGH TEMPERATURES SATURDAY JANUARY 11 RIC 72/1975 ORF 75/1974 SBY 68/1975 ECG 75/1974 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ635>638. SMALL CRAFT ADVISORY FROM 4 AM SATURDAY TO 6 AM EST SUNDAY FOR ANZ630>634-650-652-654-656-658. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ SHORT TERM...AJZ/MAM LONG TERM...TMG AVIATION...JDM/DAP MARINE...JDM CLIMATE...
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
333 PM CST FRI JAN 10 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 255 PM CST FRI JAN 10 2014 BEGINNING TO LOOK LIKE FZDZ MIGHT BE ABOUT ALL THE MPX AREA SEES FROM THE UPPER WAVES WORKING ACROSS THE CENTRAL CONUS NOW. THE PROBLEM CONTINUES TO BE A DELAYED PHASING OF A NORTHERN STREAM WAVE CURRENTLY HEADING FOR NW MN AND A SRN STREAM WAVE THAT IS MOVING UP OUT OF IA TOWARD WI. THESE TWO SYSTEMS DO NOT REALLY LOOK TO BECOME ONE UNTIL SAT MORNING OVER MICH. THE RUB THERE IS THAT THE SRN STREAM WAVE IS THE ONE WITH ALL OF THE MOISTURE AND THEREFORE PRECIPITATION AND WITH THESE SYSTEMS NOT PHASING UNTIL SATURDAY...WE ARE SEEING THE PRECIPITATION MOVING THROUGH FASTER AND FARTHER EAST TODAY/TONIGHT. RUNS OF THE HOPWRF TODAY HAVE BEEN PROGRESSIVELY INCHING A DEFORMATION BAND EAST WITH TIME AND WITH THE 15Z RUN ALL 4 MEMBERS ARE NOW SHOWING A BAND OF ENHANCED PRECIP FALLING FROM ABOUT DECORAH...IA UP TOWARD WAUSAU...EAST OF THE MPX CWA. ON RADAR...THERE IS A CLUSTER OF HIGHER RETURNS THAT MATCHES UP WELL WITH THESE PRECIPITATION SWATHS AND WITH THE HRRR PICKING UP ON THIS SCENARIO NOW AS WELL...CONFIDENCE IS BEGINNING TO INCREASE THAT THIS SYSTEM WILL BE A DUD IN THE SNOWFALL DEPARTMENT FOR THE MPX AREA. WITH ALL OF THAT SAID...STILL ANTICIPATE SOME LIGHT SNOW TO DEVELOP MAINLY EAST OF THE I-35 CORRIDOR AS THE SFC TROUGH THAT IS STILL HANGING OUT ALONG THE MN/DAKOTAS BORDER SLIDES EAST THIS EVENING...MEETING UP WITH THE DEEPER MOISTURE STREAMING NORTH INTO WI. HAVE FOLLOWED THE IDEA OF THE HRRR AND OTHER HI-RES MODELS WHICH SHOW JUST LIGHT QPF/SIMULATED REFLECTIVITY DEVELOPING OVER ERN MN WITHIN THE NEXT COUPLE OF HOURS BEFORE SLOWLY SLIDING EAST. SAID SFC TROUGH WILL CLEAR THE MPX AREA AROUND 9Z...WITH ANY SNOW LIKELY CUTTING OFF AFTER THAT. BASICALLY...THERE MIGHT BE ONE OR TWO LUCKY FOLKS OUT THERE THAT PICK UP A HALF INCH OF SNOW OUT OF THIS...OTHERWISE IT IS JUST A SEA OF LOW CLOUDS AND HAZE UNTIL THE SFC TROUGH CLEARS AND WINDS BECOME WNW. AS FOR TONIGHT...FOLLOWED THE IDEA OF THE RAP AND NAM OF SKIES SCATTERING OUT AT LEAST FOR A LITTLE WHILE AS BOUNDARY LAYER WINDS BECOME MORE WRLY...MUCH LIKE WHAT HAS BEEN SEEN TODAY ACROSS THE DAKOTAS. THINKING WE WOULD SEE SOME CLEARING...DID FOLLOW THE IDEA MOST GUIDANCE SHOWS OF KNOCKING LOWS BACK INTO THE LOWER TEENS FOR MUCH OF THE AREA WEST OF TWIN CITIES. NOT MUCH TO SAY ABOUT SATURDAY...OTHER CLOUDS CURRENTLY MOVING INTO NRN NODAK SWEEP THROUGH HERE DURING THE MORNING/EARLY AFTERNOON WITH HIGHS STILL LOOKING TO NESTLE UP INTO THE 5-10 DEGREES ABOVE NORMAL RANGE. SO MADE ONLY MINOR CHANGES TO EXISTING FORECAST...MAINLY JUST BLENDING IN LATEST BIAS CORRECTED MODEL DATA. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 255 PM CST FRI JAN 10 2014 LONGER TERM TRENDS CONTINUE TO INDICATE RATHER PROGRESSIVE UPPER LEVEL FLOW PATTERN OVER THE AREA DURING THE PERIOD. COOLING TREND APPEARS TO TAKE HOLD BY LATE IN THE PERIOD AS ANOTHER AREA OF COLD AIR DIVES SOUTHEAST ALONG THE AMPLIFYING HUDSON BAY VORTEX. A LIGHT MIX OF PRECIPITATION MAY STILL OCCUR UNDER STRONG WAA PATTERN UNDER STRONG 130KT H25 JET SUNDAY INTO SUNDAY NIGHT. WARMING ALOFT INDICATES FAVORABLE THICKNESS FOR POSSIBLE LIGHT ZR-/ZL- INTO THE DAY AS SURFACE TEMPERATURES WARM THROUGH THE LOWER 30S DURING TH DAY. WHATEVER IS LEFT INTO THE EVENING/SUNDAY OVERNIGHT WILL CHANGE OVER TO SNOW...BUT ONLY LIGHT QPF AMOUNTS ARE INDICATED. DETERMINISTIC EC AND GFS CONTINUE TO SHOW ANOTHER WEAK CLIPPER TYPE SYSTEM DIVING SOUTHEAST ALONG WEAK SURFACE BOUNDARY...AFFECTING MAINLY SOUTHERN CWA DURING THE MONDAY INTO MONDAY NIGHT PERIOD. TIMING IS IN QUESTION...WITH THE 12Z GFS A BIT FASTER THAN THE 12Z EC. WONT GET TOO CUTE ON TIMING OF THIS SYSTEM NOW...BUT WE COULD SEE SOME LIGHT SNOW ACCUMULATION WITH THIS AS IT PASSES THROUGH. BRIEF SHOT OF COLDER AIR ARRIVES FOR TUESDAY/TUESDAY NIGHT AHEAD OF NEXT SURGE OF PACIFIC AIR FOR WEDNESDAY. MODELS INDICATE THE NEXT MAIN SURGE OF ARCTIC AIR ARRIVES THURSDAY AND WILL LINGER THROUGH THE END OF THE PERIOD AS THE EASTERN CONUS TROUGH DIGS SOUTHEAST. AT THE MOMENT...IT DOESNT APPEAR TO BE AS COLD AS THE LAST WILL HAVE TO MONITOR DEVELOPMENT OF THE TROUGH INTO NEXT WEEK. COULD SEE SOME LIGHT SNOW/SNOW SHOWERS WITH THIS AS IT DIVES SOUTHEAST AND THE COLD AIR ARRIVES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1201 PM CST FRI JAN 10 2014 SFC TROUGH CURRENTLY APPROACHING THE WRN MN BORDER WILL BE KEY PLAYER THIS TAF PERIOD...AS WNW WINDS BEHIND IT ARE ALSO BRINGING IN MO CLR SKIES AND P6SM VIS. IFR CIGS/VIS WILL REMAIN FIRMLY IN PLACE EAST OF THIS TROUGH...WITH LITTLE IN THE WAY OF CHANGES FROM CURRENT CONDITIONS EXPECTED UNTIL IT MOVES THROUGH. HAVE IGNORED THE GFSLAMP SKY FORECAST FOR BEHIND THIS BOUNDARY...AS IT IS HARD TO BELIEVE THE LOW CIGS WILL CONTINUE TO BE A PROBLEM ONCE WNW WINDS SET IN BASED ON THE LACK OF CLOUDS CURRENTLY ACROSS THE DAKOTAS. TIMED CIG IMPROVEMENTS THROUGH BASED ON A RAP/NAM/GFS TIMING. FOR PRECIP...KMPX RADAR RETURNS THE LAST HOUR HAVE BEEN BLOSSOMING...INDICATIVE OF THE LIGHT FZDZ CURRENTLY BEING REPORTED AT MSP. EXPECT MOST OF THE FZDZ TO BE DONE BY 21Z...BUT IT IS NOT OUT OF THE QUESTION THAT WE MAY SEE NOTHING BUT FZDZ UNTIL THE SFC TROUGH MOVES THROUGH. FOR SNOW...CONFINED IT MAINLY TO EAU...WITH TIMING BASED ON THE HRRR. WITH THE NAM/RAP/HOPWRF SHOWING VERY LITTLE QPF BACK THIS FAR WEST...CONFIDENCE IN THE SNOWFALL FORECAST REMAINS LOW. AT BEST...AN INCH OF SNOW WILL BE POSSIBLE AT EAU. KMSP...HIGH CONFIDENCE IN CIG/VIS FORECAST THROUGH 03Z. AFTER THAT...CONFIDENCE DECREASES SOME WITH WHEN VFR CIGS RETURN...BUT LOOKS LIKELY TO HAPPEN IN THE 4-8Z WINDOW. MAY SEE SOME LIGHT SNOW IN THE 22-02Z WINDOW AS WELL... BUT DO NOT EXPECT VIS RESTRICTIONS TO BE ANY WORSE THAN WHAT WE ARE SEEING WITH CURRENT BR. FOR LATE SATURDAY MORNING INTO THE AFTERNOON...WILL HAVE TO WATCH HOW FAR SOUTH MVFR CIGS IN SE SASKATCHEWAN BUILD AS THEY MOVE SE PER THE NAM AND GFS. MAY SEE A FEW HOURS WERE CIGS DIP BACK DOWN TO AROUND 020 AS THAT BIT OF MOISTURE MOVES THROUGH. /OUTLOOK FOR KMSP/ SUN...VFR. WINDS SW 10-15 KTS. MON...VFR. CHC MVFR/-SN OVERNIGHT. WINDS W-SW 5-10 KTS. TUE...VFR. CHC MVFR CIGS. WINDS NW 15G25 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...DWE AVIATION...MPG
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1123 AM CST FRI JAN 10 2014 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 338 AM CST FRI JAN 10 2014 THE RAP HAS ANALYZED A H500 MB SHORT WAVE ACROSS ERN WYOMING THIS MORNING. THE PV15 ANOMALY EXTENDS FROM KCYS SOUTH THROUGH KDEN. IF THE RAP AND THE OTHER MODELS ARE CORRECT THEN SCATTERED SNOW SHOWERS SHOULD DEVELOP ACROSS NW NEB IN A FEW HOURS AND MOVE SOUTHEAST THROUGH SWRN AND SCNTL NEB. THE ONGOING RADAR RETURNS ACROSS NERN COLO ARE RAIN AND THE SNOW SHOWERS SHOULD DEVELOP ONCE THE THERMAL RIDGE ACROSS SWRN NEB MOVES EAST LATER THIS MORNING. OTHERWISE...THE ARCTIC DRAPE WILL MOVE EAST OF THE FCST AREA IN A FEW HOURS AHEAD THE SHORT WAVE AND ALL OF THIS WEATHER SHOULD EXIT THE FCST AREA TO THE EAST BY 21Z PROVIDING FOR A PARTLY SUNNY AFTERNOON WITH HIGHS IN THE UPPER 30S TO MID 40S. FOR TONIGHT...A WEAK COLD FRONT WILL BE PRESSING INTO NRN NEBRASKA TOWARD MORNING. THERE IS VERY LITTLE THERMAL RIDGING AHEAD OF THE FRONT AND H850 WINDS INCREASE FROM 25 TO 35 KT FRIDAY EVENING TO 40 TO 50 KT BY SATURDAY MORNING. ALL OF THIS SUGGESTS...GIVEN THE GENERALLY CLEAR SKIES TONIGHT...LOWS IN THE 20S MOST AREAS WITH TEENS IN THE PLATTE VALLEY AND CUSTER COUNTY. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 338 AM CST FRI JAN 10 2014 LITTLE CHANGE TO THE OVERALL PATTERN WITH A RIDGE IN THE WEST AND A TROUGH IN THE EAST...AND NORTHWEST FLOW ACROSS THE HIGH PLAINS. SEVERAL WEAK TROUGHS/CLIPPERS WILL PUSH ACROSS THE PLAINS...WITH A SLIGHT WARM UP AHEAD OF THE SYSTEM...AND A SLIGHT COOL DOWN WITH AN INCREASE OF CLOUDS WITH EACH TROUGH. WARM AIR ARRIVES FOR SATURDAY AHEAD OF THE NEXT TROUGH HIGHS NEARING THE MID 50S FOR THE SW AS 850 MB TEMPS PUSH TO AROUND 10 C. COOLER OVER N CENTRAL...MID 40S WITH 850 MB TEMPS CLOSER TO ZERO. SATURDAY NIGHT INTO SUNDAY THE TROUGH WILL CROSS THE CWA. MIXING ALONG AHEAD OF THE TROUGH WILL PUSH TEMPS BACK TO AROUND 50...WITH THE NW HOLDING CLOSER TO 40. THERE IS A CHANCE FOR SOME VERY LIGHT PRECIP /FLURRIES OR SPRINKLES/ ALTHOUGH LOW CONFIDENCE. MODELS HAVE SEVERAL MARGINAL POSITIVES TO LIGHT PRECIP...HOWEVER THEY ARE NOT OVERLAPPING. THE NW ZONES HAS THE STEEPEST LAPSE RATES HOWEVER THE RIGHT ENTRANCE TO A JET STREAK FAVORS THE SW. LL MOISTURE IS LIMITED AND MODELS VARY WITH POCKETS OF LOWER CONDENSATION DEFICITS...LESS THAN 20 MB. BY SUNDAY EVENING TROUGH AXIS IS EAST AND ANY LIGHT PRECIP WILL HAVE ENDED. MONDAY THE RIDGE RETURNS LATE IN THE DAY...AND HIGHS SHOULD REBOUND LATE TO AROUND 50 SW TO MID 50S N. BY MONDAY NIGHT A WEAK UPPER LEVEL DISTURBANCE TO RIDE THE NW FLOW. BETTER ENERGY IS ACROSS THE NORTHERN PLAINS...HOWEVER MAY GET SOME LIGHT SNOW ACROSS THE NW...WHERE MODELS HAVE A LITTLE UPPER LEVEL SUPPORT FROM THE LEFT EXIT REGION OF THE NEXT JET STREAK. THIS WILL WEAK SYSTEM WILL QUICKLY PASS TO THE EAST ON TUESDAY...ALTHOUGH SOME LINGERING CLOUDS EARLY ON IN THE DAY MAY LIMIT HEATING AND FOLLOWED SLIGHT COOL DOWN FROM THE DAY BEFORE...PER GUIDANCE. AS SYSTEM DIGITS ACROSS THE GREAT LAKES REGION/MID ATLANTIC FOR WEDNESDAY...RIDGE EXPANDS ACROSS THE WEST. MODELS IN GOOD AGREEMENT WITH ANOTHER SURGE OF WARMER AIR ACROSS THE HIGH PLAINS. HIGHS ONCE AGAIN INTO THE MID AND UPPER 50S FOR SW NEB AND UPPER 40S ELSEWHERE. THIS WARM AIR WILL BE AHEAD OF THE NEXT CLIPPER WHICH SHOULD ARRIVE WED NIGHT. THIS WILL BRING ANOTHER COOL DOWN FOR THURSDAY. ONE COMMON THEME THROUGH THE END OF THE WEEKEND INTO NEXT WEEK WILL BE BREEZY TO WINDY CONDITIONS. FAST MOVING SYSTEMS ARE STEERED BY SWIFT WINDS ALOFT AND WITH HIGHS ABOVE SEASONAL AVERAGES...GOOD MIXING WILL TAP INTO THE STRONGER WINDS. DAY TIME SFC WINDS OF 15 TO 30 MPH...WITH HIGHER GUSTS...CAN BE EXPECTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1120 AM CST FRI JAN 10 2014 MAIN CONCERN FOR THE CURRENT TAF PERIOD IS THE POTENTIAL FOR SNOW SHOWERS ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THROUGH FRIDAY AFTERNOON...MAINLY IMPACTING THE KLBF TERMINAL WHERE A TEMPO GROUP HAS BEEN INCLUDED FOR -SHSN AND VISBYS DOWN TO 3SM OR LESS IN THE 18Z TO 21Z TIME FRAME. SKIES WILL BEGIN TO CLEAR UP LATE THIS AFTERNOON AND EVENING WITH VFR CONDITIONS EXPECTED THROUGH 18Z SATURDAY. A STRATUS DECK WILL MOVE INTO KVTN TOWARD THE EARLY MORNING HOURS SATURDAY...HOWEVER AT THIS TIME IT LOOKS TO REMAIN ABOVE MVFR LEVELS. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
ISSUED BY NATIONAL WEATHER SERVICE CHARLESTON SC 1249 PM EST FRI JAN 10 2014 .SYNOPSIS... A COASTAL FRONT HAS PUSHED INLAND TODAY...ALLOWING HUMID SUBTROPICAL AIR INTO THE AREA. AN EASTWARD MOVING COLD FRONT WILL SWEEP ACROSS THE AREA LATE SATURDAY. WEAK HIGH PRESSURE WILL COVER THE SOUTHEAST STATES SUNDAY AND MONDAY. LOW COAST LOW PRESSURE WILL PASS SOUTH OF THE CAROLINAS TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MOST PRECIP HAS MOVED OUT OF THE CWA WITH ONLY SMALL RETURNS SHOWING ON RADAR. SLIGHT MODEL DIFFERENCES WITH RESPECT TO SHOWERS THIS AFTERNOON. HRRR AND NAM FLIRT WITH SHOWERS OVER THE WESTERN COUNTIES. KEPT POPS IN THE 40 TO 60 PERCENT RANGE TO ACCOUNT FOR DEVELOPING SHOWERS AS TEMPS...HUMIDITY AND ISENTROPIC ASCENT CONTINUE TO INCREASE. THERE IS ROUGHLY A 20 DEGREE TEMP GRADIENT BETWEEN THE COASTAL AND INLAND COUNTIES AS THE WARM FRONT HAS PROGRESSED WEST. STILL EXPECT THIS FEATURE TO STALL NEAR THE I95 CORRIDOR && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... EXPECT A WARM AND WET FIRST HALF OF THE WEEKEND IN SHOWERS AND ISOLATED THUNDERSTORMS AS COLD FRONT MAKES ITS WAY THROUGH THE CAROLINAS ON SATURDAY. ENTRENCHED IN THE WARM SECTOR ON SATURDAY...TEMPS WILL REACH INTO THE 70S MOST PLACES WITH DEWPOINT TEMPS INTO THE MID 60S. LLJ INCREASES UP TO 50 KTS WITH PCP WATER VALUES REACHING ABOVE 1.5 INCHES BY SAT AFTN. OVERALL CAPE SEEMS FAIRLY LOW BUT MAY SEE SOME STRONGER WINDS ALOFT MAKE IT DOWN TO SURFACE IN DEEPER CONVECTIVE DEVELOPMENT THROUGH SAT AFTN INTO EARLY SAT EVENING. ONCE COOLING OCCURS AT SURFACE EXPECT ANY STRONGER CONVECTION TO WANE. SPC CONTINUES TO KEEP AREA IN SLIGHT RISK OF SEVERE THUNDERSTORMS WITH MAIN THREAT OF POTENTIAL FOR DAMAGING WIND GUSTS. BEST UPPER LEVEL SUPPORT LOOKS LIKE IT WILL BE HELD BACK TO THE WEST WITH H5 TROUGH CROSSING THE COAST AFTER MIDNIGHT. EXPECT HEAVIER RAIN IN SHOWERS AND THUNDERSTORMS TO PRODUCE RAINFALL TOTALS UP AROUND AN INCH OR HIGHER IN SPOTS. COLD FRONT WILL MAKE ITS WAY OFF SHORE BY MIDNIGHT SAT NIGHT WITH DRIER AIR ADVECTING IN AS HIGH PRESSURE BUILDS IN BEHIND IT. SKIES WILL CLEAR WITH DEEP DRY COLUMN BY SUNDAY WITH PCP WATER VALUES DOWN CLOSE TO A QUARTER OF AN INCH. RIDGE OF HIGH PRESSURE WILL BUILD RAPIDLY EAST BEHIND FRONT WITH WINDS MAINTAINING A STRONG WESTERLY COMPONENT TO THE FLOW. THIS WILL ALLOW FOR QUICK RECOVERY OF TEMPS. THE 850 TEMPS UP AROUND 12C WILL DROP DOWN CLOSE TO 2 C BY SUN MORNING BUT WILL BOUNCE BACK AS WINDS COME AROUND TO THE W-SW THROUGH SUNDAY. HIGH TEMPS ON SAT WILL REACH INTO THE 70S BUT WILL DROP DOWN BEHIND COLD FRONT SAT NIGHT DOWN BELOW 50 BY MORNING. SUNDAY WILL RECOVER TO AROUND 60 UNDER SUNNY SKIES AIDED BY DECENT DOWNSLOPE WESTERLY WIND. TEMPS SUNDAY NIGHT WILL BE CLOSER TO NORMAL WITH MID TO UPPER 30S MOST PLACES. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... WINDS WILL ALREADY BE BACK AROUND TO THE SOUTHWEST ON MONDAY WITH WARMER AND MOISTER AIR ADVECTING OVER THE CAROLINAS IN A MUCH MORE PROGRESSIVE PATTERN. MODELS STILL SHOWING HIGH PRESSURE OFF THE COAST BY MONDAY AS DEEPENING MID TO UPPER TROUGH PUSHES NEXT SYSTEM EAST. THE GFS RUNNING A BIT SLOWER AGAIN LINING UP SLIGHTLY BETTER WITH ECMWF BUT STILL KEEPS WAVE OF LOW PRESSURE RIDING UP FROM THE GULF FARTHER EAST WITH MOST PCP LINING UP RIGHT ALONG THE COAST OR IN THE ATLANTIC WATERS BY MON NIGHT. OVERALL EXPECT INCREASING CLOUDS BY LATE MONDAY WITH BEST CHC OF PCP OVERNIGHT MONDAY AS LOW MOVES UP THE COAST AND COLD FRONT APPROACHES FROM THE W-NW. WILL NOT TAP INTO TOO MUCH IN THE WAY OF GULF MOISTURE AND THEREFORE NOT COUNTING ON GREAT QPF MON NIGHT AS PCP WATER VALUES REACH AROUND AN INCH BEFORE DROPPING DOWN TO A QUARTER OF INCH BY TUES AFTERNOON IN DEEP DRY AND COOL ADVECTION. WILL GET ANOTHER REINFORCING SHOT OF COOL AIR BY LATE WEDNESDAY AS MID TO UPPER TROUGH DIGS DOWN ACROSS THE SOUTHEAST AND MOVES THROUGH. WITH FLOW REMAINING PROGRESSIVE THROUGH THE WEEK...HIGH PRESSURE BUILDING UP FROM THE GULF ON THURS WILL SHIFT OFF SHORE BY FRIDAY WITH A TRANSITION TO A SOUTHERLY RETURN FLOW BRIEFLY THROUGH FRI. TEMPS WILL REMAIN CLOSER TO NORMAL AFTER BEING KNOCKED DOWN BEHIND COLD FRONT ON TUES...WITH READINGS IN THE MID 50S FOR HIGHS AND 30S AT NIGHT THROUGH MUCH OF THE WEEK AHEAD. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... SHOWERS HAVE MOVED OUT OF THE CWA AND MOST TERMINALS ARE EXPECTED TO BE VFR. THERE ARE SOME SCATTERED AREAS OF MVFR CIGS WHERE THE DEW POINT DEPRESSIONS ARE SMALLER. A VERY MOIST AIR MASS WILL BE IN PLACE OVERNIGHT...EXPECT AN INCREASED POTENTIAL FOR FOG/STRATUS. BEST CHANCES FOR IFR CIGS WILL BE AT KFLO/KLBT...WHILE KCRE/KMYR COULD BATTLE SEA FOG AS THE WINDS BECOME MORE SOUTHERLY TONIGHT. EXTENDED OUTLOOK...SHOWERS WITH ISOLATED T-STORMS AND MVFR/IFR CONDITIONS ON SATURDAY. ALSO EXPECT GUSTY SOUTH WINDS ON SATURDAY AHEAD OF THE COLD FRONT. VFR SUNDAY THROUGH TUESDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... SEAS WILL GRADUALLY BUILD AS HIGH AS 6-7 FEET OUT NEAR 20 MILES FROM SHORE. WIND DIRECTIONS WILL VEER MORE SOUTHERLY TONIGHT AS A COLD FRONT CROSSES THE LOWER MISSISSIPPI VALLEY. THIS WILL INCREASE THE TIME AIR PARCELS PASS OVER THE COLDER NEARSHORE WATERS ALONG THE SOUTH CAROLINA COAST AND ALSO JUST NORTH OF CAPE FEAR...OPENING THE WINDOW FOR PATCHY SEA FOG AS THE AIR IS CHILLED BY ITS PASSAGE ACROSS THE COLD NEARSHORE OCEAN. WIND SPEEDS SHOULD DIMINISH SLIGHTLY AS WELL...PERHAPS LEAVING A PERIOD OF 6-10 HOURS WHERE WE DON`T MEET SMALL CRAFT ADVISORY CONDITIONS TONIGHT INTO EARLY SATURDAY MORNING. AFTER COLLABORATING WITH THE WEEKEND FORECASTER WHO EXPECTS INCREASING WIND SPEEDS SATURDAY...THE ADVISORY WILL REMAIN POSTED INTO SUNDAY. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... WINDS WILL CONTINUE TO INCREASE AND VEER AROUND FROM THE S TO SW ON SATURDAY AHEAD OF THE APPROACHING COLD FRONT...BECOMING 20-25 KTS OR MORE...WITH GUSTS TO GALE FORCE POSSIBLE SATURDAY EVE...BEFORE THE COLD FRONT CROSSES BY WITH A WIND SHIFT TO THE W-NW AT AROUND 20 KTS OVERNIGHT. THESE INCREASING SOUTHERLY WINDS AHEAD OF THE FRONT WILL CONTINUE TO DRIVE SEAS UP TO 6 TO 9 FT BY LATE SATURDAY MAINTAINING SMALL CRAFT ADVISORY CONDITIONS THROUGH SATURDAY INTO SUNDAY MORNING. WINDS AND SEAS SHOULD PEAK JUST AHEAD OF THE COLD FRONT SAT EVENING. A GALE WARNING MAY BE NEEDED INSTEAD IF WINDS END UP JUST A BIT STRONGER SAT EVENING. AS WINDS BECOME OFF SHORE BEHIND COLD FRONT AFTER MIDNIGHT SAT NIGHT...THE SEAS WILL DROP OFF ESPECIALLY NEAR SHORE. WINDS SHOULD DIMINISH TO 15 TO 20 KTS BY SUN MORNING DECREASING FURTHER THROUGH THE DAY AS HIGH PRESSURE MOVES ACROSS THE SOUTHEAST. BY NOON ON SUNDAY WINDS AND SEAS SHOULD BEGIN TO DROP BELOW SCA THRESHOLDS AND WILL DROP RAPIDLY DOWN TO 2 TO 4 FT BY SUN NIGHT AS WINDS LIGHTEN AS HIGH PRESSURE MOVES OVERHEAD. LONG TERM /MONDAY THROUGH TUESDAY... RETURN FLOW AROUND 10 TO 15 KTS WILL INCREASE THROUGH LATE MONDAY INTO TUESDAY AS HIGH PRESSURE SHIFTS FARTHER OFF SHORE AND A COLD FRONT APPROACHES FROM THE NORTHWEST AND WAVE OF LOW PRESSURE MOVES UP FROM THE GULF COAST INTO THE ATLANTIC WATERS. THE WARMER WINDS MOVING OVER THE VERY COOL SHELF WATERS WILL MAINTAIN A MORE STABLE MARINE LAYER PREVENTING THE WINDS FROM REACHING THE OCEAN SURFACE. SEAS WILL THEREFORE NOT HAVE MUCH TIME TO BUILD BEFORE COLD FRONT MOVES THROUGH AND WINDS SHIFT AROUND TO THE W-NW AGAIN BY TUES AFTN. THE SEAS WILL QUICKLY BUILD OVER THE OUTER WATERS OFF CAPE FEAR THROUGH MON AFTN AND COULD REACH 5 FT BEFORE DROPPING AGAIN THROUGH EARLY TUES BEHIND FRONT. WNA SHOWING WINDS BACKING AND INCREASING THROUGH TUES NIGHT ONCE AGAIN AS HIGH PRESSURE BUILDS IN FROM THE WEST. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST SUNDAY FOR AMZ250-252-254- 256. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
540 PM EST FRI JAN 10 2014 .SYNOPSIS... AN APPROACHING UPPER LEVEL TROUGH WILL MOVE INTO THE AREA TONIGHT...WITH RAIN EXPECTED TONIGHT AND INTO SATURDAY. A COLD FRONT WILL CROSS THE REGION BY SATURDAY AFTERNOON...LOWERING TEMPERATURES THROUGH SUNDAY. HIGH PRESSURE WILL ENTER THE SOUTHEASTERN STATES ON SUNDAY...WITH RIDGING BRINGING FAIR CONDITIONS TO THE OHIO VALLEY THROUGH EARLY MONDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... A QUICK UPDATE HAS BEEN PRODUCED TO ALLOW FOR THE ISSUANCE OF A DENSE FOG ADVISORY. THE AREA OF DENSE FOG HAS CONTINUED TO EXPAND NORTHWARD...ENVELOPING LARGE ENOUGH SECTIONS OF SEVERAL COUNTIES TO REQUIRE AN ADVISORY TO BE ISSUED. THE SOUTHERN EDGE OF THIS ADVISORY WILL LIKELY BE ABLE TO BE DROPPED EARLY...AS VISIBILITIES ARE VERY GRADUALLY IMPROVING FROM THE SOUTH. HOWEVER...THE NEWEST HIGH-RESOLUTION MODEL DATA INDICATES THAT SURFACE SATURATION IS LIKELY TO CONTINUE IN THE NORTHWESTERN CWA FOR AT LEAST SEVERAL MORE HOURS. PREVIOUS DISCUSSION > THE PRIMARY WEATHER CONCERN FOR THE NEAR TERM IS FOG POTENTIAL. A NARROW AXIS FROM THE WEST-CENTRAL CWA (AROUND FRANKLIN COUNTY INDIANA) THROUGH THE NORTHEAST CWA (DELAWARE COUNTY OHIO) CONTAINS A FEW OBSERVATION SITES REPORTING QUARTER-MILE DENSE FOG. RH PROJECTIONS AND SREF/HRRR/RAP VISIBILITY PRODUCTS ALL INDICATE A POTENTIAL FOR THIS TO CONTINUE TONIGHT...WITH THE LOWER VISIBILITIES GRADUALLY SHIFTING NORTH AND WEST WITH TIME. FOR NOW THIS THREAT WILL BE COVERED BY THE HWO AND A NEW SPECIAL WEATHER STATEMENT...BUT IF THE DENSE AREA EXPANDS AT ALL...AN ADVISORY MAY BECOME NECESSARY. RIGHT NOW...THIS AREA IS FAIRLY NARROW AND NOT WIDESPREAD ENOUGH TO REQUIRE A HEADLINE. INCREASING ISENTROPIC LIFT AHEAD OF A DEEPENING MID-LEVEL TROUGH WILL GRADUALLY LEAD TO AN INCREASE IN PRECIPITATION POTENTIAL THIS EVENING...PRIMARILY FOR THE WESTERN HALF OF THE CWA. DESPITE THE RELATIVELY ABUNDANT LOW-LEVEL MOISTURE...IT IS NOT APPARENT THAT CURRENT ECHOES IN THE SOUTHWEST CWA ARE REACHING THE GROUND...SO MEASURABLE PRECIPITATION MAY STILL BE A FEW HOURS OFF. MOST OF THE IMPACTS FROM THE APPROACHING TROUGH AND COLD FRONT WILL BE COVERED IN THE SHORT TERM DISCUSSION. TEMPERATURES OVERNIGHT ARE EXPECTED TO REMAIN RELATIVELY STEADY FOR A WHILE...BEFORE RISING (ESPECIALLY IN THE SOUTHERN CWA) CLOSER TO DAYBREAK. THE RAP WAS USED AS A BASIS FOR THESE NON-DIURNAL TEMPERATURES...AS IT IS HANDLING THE CURRENT SITUATION WELL. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AHEAD OF A MID-LEVEL TROUGH MOVING EAST OUT OF THE MISSISSIPPI VALLEY...A SURFACE LOW WILL TRACK NORTHEASTWARD INTO THE GREAT LAKES REGION ON SATURDAY. THIS WILL BRING A COLD FRONT THROUGH THE OHIO VALLEY BY SATURDAY AFTERNOON. AHEAD OF THE COLD FRONT...THE OHIO VALLEY WILL BE WITHIN A REGIME OF DEEP SOUTHERLY FLOW...ADVECTING A VERY MOIST AIR MASS INTO THE REGION. BY EARLY SATURDAY MORNING...PRECIPITABLE WATER VALUES WILL BE WELL OVER AN INCH ACROSS THE ILN CWA...EXCEEDING 300 PERCENT OF NORMAL FOR JANUARY. THE STRONGEST PUSH OF MOISTURE WILL COME ON THE NOSE OF A LOW LEVEL JET BETWEEN 08Z AND 12Z...FOCUSED PRIMARILY ON THE SOUTHERN AND SOUTHEASTERN SECTIONS OF THE ILN CWA. WITH SOUNDINGS APPEARING MOIST ADIABATIC (AS WOULD BE EXPECTED)...INSTABILITY WILL BE HARD TO COME BY. THERE APPEARS TO BE JUST ENOUGH CONDITIONAL ELEVATED INSTABILITY TO SUPPORT A CHANCE OF THUNDER IN THE SOUTH AND SOUTHEAST CWA EARLY SATURDAY MORNING...AND AT THE VERY LEAST...SOME OF THE SHOWERS WILL LIKELY BE A LITTLE BIT CONVECTIVE IN NATURE. THE LARGER-SCALE MODELS INDICATE PRECIPITATION TOTALS OF GENERALLY JUST UNDER AN INCH...WHILE SOME OF THE MESOSCALE MODELS SHOW AN AXIS OF OVER AN INCH THAT WORKS THROUGH THE SOUTH-CENTRAL PORTIONS OF THE ILN CWA. BASED ON THE APPEARANCE OF SIMULATED REFLECTIVITY ON THE HIGH-RES RUNS...AND THE POTENTIAL FOR SOME ISOLATED ELEVATED CONVECTIVE ELEMENTS...SOME LOCALIZED PRECIPITATION AMOUNTS MAY GET AS HIGH AS AN INCH AND A HALF. BASED ON FLASH FLOOD GUIDANCE AND MMEFS RUNS (USING NAEF/SREF/GEFS INPUT)...IT DOES NOT APPEAR THAT THIS WILL BE ENOUGH RAIN TO LEAD TO SIGNIFICANT FLOODING ISSUES. A FEW ACTION STAGE RIVER READINGS...OR PERHAPS AN ADVISORY OR TWO...MAY NOT BE OUT OF THE QUESTION. NON-DIURNAL TEMPERATURE TRENDS ARE BEING CONTINUED THROUGH SATURDAY...AS COLD FRONTAL PASSAGE OCCURS. DEEP MOISTURE WILL DISAPPEAR AFTER THE FRONT HAS PASSED...BUT POPS WILL BE MAINTAINED AS ADDITIONAL RAIN SHOWERS (MIXING WITH SNOW LATE) APPEAR LIKELY. THIS POST-FRONTAL REGIME (UNDER THE MID-LEVEL TROUGH AXIS) WILL BE CHARACTERIZED BY A MIXED LAYER WITH WEAK AND SHALLOW INSTABILITY...AND ABUNDANT LOW- LEVEL MOISTURE. EVENTUALLY...AS THE NIGHT PROGRESSES...MOISTURE BECOMES SHALLOW ENOUGH THAT ICE CRYSTALS MAY NOT BE ABLE TO FORM. FLURRIES HAVE BEEN INTRODUCED THROUGH SATURDAY NIGHT...BUT IT IS VERY POSSIBLE THAT THIS WILL END UP BEING DRIZZLE (OR EVEN FREEZING DRIZZLE BASED ON SURFACE TEMPS). BY SUNDAY MORNING...RIDGING WILL BE ENTERING THE CWA...WITH SURFACE HIGH PRESSURE BUILDING IN FROM THE SOUTH. THE LOW LEVEL MOISTURE MAY NOT ALLOW CLOUDS TO SCOUR VERY QUICKLY...BUT MOSTLY SUNNY SKIES ARE EXPECTED BY AFTERNOON FOR MOST OF THE CWA (WITH CLOUDS DISSIPATING EARLIER IN THE SOUTH). WITH THE CWA RETURNING TO A WARM ADVECTION PATTERN...TEMPS WILL RISE AGAIN ON SUNDAY...AND STRUGGLE TO EVEN CROSS BACK UNDER THE FREEZING MARK ON SUNDAY NIGHT / EARLY MONDAY MORNING. && .LONG TERM /MONDAY THROUGH FRIDAY/... RAIN WILL BE LIKELY MONDAY AS A SURGE OF GULF MOISTURE MOVES UP A FRONTAL BOUNDARY ON A SOUTHWEST UPPER FLOW. SOME LOCATIONS MAY SEE AN INCH OF RAIN WITH THIS EVENT. RAIN AND SNOW SHOWERS ARE POSSIBLE FOR TUESDAY IN THE NORTHWEST FLOW BEHIND THE FRONT. SNOW SHOWERS MAY LINGER ON WEDNESDAY IN THE COLDER NORTHWEST FLOW. A PERIOD OF DRY WEATHER IS INDICATED FOR THURSDAY WHEN A RIDGE OF HIGH PRESSURE IS FORECAST TO PUSH ACROSS THE REGION. SNOW SHOWERS WILL BE POSSIBLE AGAIN ON FRIDAY DUE TO A TROUGH AND ASSOCIATED MOISTURE AND COLD ADVECTION. TEMPERATURES WILL START ABOVE NORMAL MONDAY AND TUESDAY...WITH HIGHS MAINLY IN THE 40S. COLD ADVECTION WILL PUSH READINGS BELOW NORMAL ON WEDNESDAY AND FRIDAY WITH HIGHS IN THE 20S...WHILE THE RIDGE WILL PROVIDE SOME WARM ADVECTION AND NEAR NORMAL 30S FOR THURSDAY. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... ABUNDANT LOW LEVEL MOISTURE SHROUDING ILN/S TAFS IN IFR CIGS AND IFR/MVFR VSBYS IN FOG NORTH OF E-W ORIENTED WARM FRONT. LOW CLOUDS AND VSBYS WILL BE SLOW TO IMPROVE THRU THE AFTN. NEXT MID LEVEL TROF TO SHARPEN UP OVER THE PLAINS WITH MID LEVEL FLOW BACKING ACRS THE OHIO VALLEY. FAVORABLE ISENTROPIC LIFT WILL DEVELOP AHD OF THIS SYSTEM DURG THE AFTN. BASED ON LATEST MODEL TRENDS HAVE VCSH DEVELOPING DURG EARLY EVENING AND THEN PREVAILING RAIN DEVELOPING BETWEEN 04Z AND 07Z. EXPECT IFR CIGS WITH MVFR VSBYS DURG RAIN. COLD FRONT EXPECTED TO SWEEP EAST THRU THE TAF SITES DURG EARLY MORNING SATURDAY. WINDS WILL SHIFT TO THE WEST AND GUST UP TO 26 KTS. EXPECT MVFR CIGS TO LINGER THRU SATURDAY AFTN. OUTLOOK...MVFR TO IFR CEILINGS LIKELY THROUGH SATURDAY NIGHT. MVFR VISIBILITIES POSSIBLE INTO EARLY SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...DENSE FOG ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR OHZ026-034- 035-042>045-051>053-060-061. KY...NONE. IN...DENSE FOG ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR INZ050-058- 059. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
357 PM EST FRI JAN 10 2014 .SYNOPSIS... AN APPROACHING UPPER LEVEL TROUGH WILL MOVE INTO THE AREA TONIGHT...WITH RAIN EXPECTED TONIGHT AND INTO SATURDAY. A COLD FRONT WILL CROSS THE REGION BY SATURDAY AFTERNOON...LOWERING TEMPERATURES THROUGH SUNDAY. HIGH PRESSURE WILL ENTER THE SOUTHEASTERN STATES ON SUNDAY...WITH RIDGING BRINGING FAIR CONDITIONS TO THE OHIO VALLEY THROUGH EARLY MONDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... THE PRIMARY WEATHER CONCERN FOR THE NEAR TERM IS FOG POTENTIAL. A NARROW AXIS FROM THE WEST-CENTRAL CWA (AROUND FRANKLIN COUNTY INDIANA) THROUGH THE NORTHEAST CWA (DELAWARE COUNTY OHIO) CONTAINS A FEW OBSERVATION SITES REPORTING QUARTER-MILE DENSE FOG. RH PROJECTIONS AND SREF/HRRR/RAP VISIBILITY PRODUCTS ALL INDICATE A POTENTIAL FOR THIS TO CONTINUE TONIGHT...WITH THE LOWER VISIBILITIES GRADUALLY SHIFTING NORTH AND WEST WITH TIME. FOR NOW THIS THREAT WILL BE COVERED BY THE HWO AND A NEW SPECIAL WEATHER STATEMENT...BUT IF THE DENSE AREA EXPANDS AT ALL...AN ADVISORY MAY BECOME NECESSARY. RIGHT NOW...THIS AREA IS FAIRLY NARROW AND NOT WIDESPREAD ENOUGH TO REQUIRE A HEADLINE. INCREASING ISENTROPIC LIFT AHEAD OF A DEEPENING MID-LEVEL TROUGH WILL GRADUALLY LEAD TO AN INCREASE IN PRECIPITATION POTENTIAL THIS EVENING...PRIMARILY FOR THE WESTERN HALF OF THE CWA. DESPITE THE RELATIVELY ABUNDANT LOW-LEVEL MOISTURE...IT IS NOT APPARENT THAT CURRENT ECHOES IN THE SOUTHWEST CWA ARE REACHING THE GROUND...SO MEASURABLE PRECIPITATION MAY STILL BE A FEW HOURS OFF. MOST OF THE IMPACTS FROM THE APPROACHING TROUGH AND COLD FRONT WILL BE COVERED IN THE SHORT TERM DISCUSSION. TEMPERATURES OVERNIGHT ARE EXPECTED TO REMAIN RELATIVELY STEADY FOR A WHILE...BEFORE RISING (ESPECIALLY IN THE SOUTHERN CWA) CLOSER TO DAYBREAK. THE RAP WAS USED AS A BASIS FOR THESE NON-DIURNAL TEMPERATURES...AS IT IS HANDLING THE CURRENT SITUATION WELL. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AHEAD OF A MID-LEVEL TROUGH MOVING EAST OUT OF THE MISSISSIPPI VALLEY...A SURFACE LOW WILL TRACK NORTHEASTWARD INTO THE GREAT LAKES REGION ON SATURDAY. THIS WILL BRING A COLD FRONT THROUGH THE OHIO VALLEY BY SATURDAY AFTERNOON. AHEAD OF THE COLD FRONT...THE OHIO VALLEY WILL BE WITHIN A REGIME OF DEEP SOUTHERLY FLOW...ADVECTING A VERY MOIST AIR MASS INTO THE REGION. BY EARLY SATURDAY MORNING...PRECIPITABLE WATER VALUES WILL BE WELL OVER AN INCH ACROSS THE ILN CWA...EXCEEDING 300 PERCENT OF NORMAL FOR JANUARY. THE STRONGEST PUSH OF MOISTURE WILL COME ON THE NOSE OF A LOW LEVEL JET BETWEEN 08Z AND 12Z...FOCUSED PRIMARILY ON THE SOUTHERN AND SOUTHEASTERN SECTIONS OF THE ILN CWA. WITH SOUNDINGS APPEARING MOIST ADIABATIC (AS WOULD BE EXPECTED)...INSTABILITY WILL BE HARD TO COME BY. THERE APPEARS TO BE JUST ENOUGH CONDITIONAL ELEVATED INSTABILITY TO SUPPORT A CHANCE OF THUNDER IN THE SOUTH AND SOUTHEAST CWA EARLY SATURDAY MORNING...AND AT THE VERY LEAST...SOME OF THE SHOWERS WILL LIKELY BE A LITTLE BIT CONVECTIVE IN NATURE. THE LARGER-SCALE MODELS INDICATE PRECIPITATION TOTALS OF GENERALLY JUST UNDER AN INCH...WHILE SOME OF THE MESOSCALE MODELS SHOW AN AXIS OF OVER AN INCH THAT WORKS THROUGH THE SOUTH-CENTRAL PORTIONS OF THE ILN CWA. BASED ON THE APPEARANCE OF SIMULATED REFLECTIVITY ON THE HIGH-RES RUNS...AND THE POTENTIAL FOR SOME ISOLATED ELEVATED CONVECTIVE ELEMENTS...SOME LOCALIZED PRECIPITATION AMOUNTS MAY GET AS HIGH AS AN INCH AND A HALF. BASED ON FLASH FLOOD GUIDANCE AND MMEFS RUNS (USING NAEF/SREF/GEFS INPUT)...IT DOES NOT APPEAR THAT THIS WILL BE ENOUGH RAIN TO LEAD TO SIGNIFICANT FLOODING ISSUES. A FEW ACTION STAGE RIVER READINGS...OR PERHAPS AN ADVISORY OR TWO...MAY NOT BE OUT OF THE QUESTION. NON-DIURNAL TEMPERATURE TRENDS ARE BEING CONTINUED THROUGH SATURDAY...AS COLD FRONTAL PASSAGE OCCURS. DEEP MOISTURE WILL DISAPPEAR AFTER THE FRONT HAS PASSED...BUT POPS WILL BE MAINTAINED AS ADDITIONAL RAIN SHOWERS (MIXING WITH SNOW LATE) APPEAR LIKELY. THIS POST-FRONTAL REGIME (UNDER THE MID-LEVEL TROUGH AXIS) WILL BE CHARACTERIZED BY A MIXED LAYER WITH WEAK AND SHALLOW INSTABILITY...AND ABUNDANT LOW- LEVEL MOISTURE. EVENTUALLY...AS THE NIGHT PROGRESSES...MOISTURE BECOMES SHALLOW ENOUGH THAT ICE CRYSTALS MAY NOT BE ABLE TO FORM. FLURRIES HAVE BEEN INTRODUCED THROUGH SATURDAY NIGHT...BUT IT IS VERY POSSIBLE THAT THIS WILL END UP BEING DRIZZLE (OR EVEN FREEZING DRIZZLE BASED ON SURFACE TEMPS). BY SUNDAY MORNING...RIDGING WILL BE ENTERING THE CWA...WITH SURFACE HIGH PRESSURE BUILDING IN FROM THE SOUTH. THE LOW LEVEL MOISTURE MAY NOT ALLOW CLOUDS TO SCOUR VERY QUICKLY...BUT MOSTLY SUNNY SKIES ARE EXPECTED BY AFTERNOON FOR MOST OF THE CWA (WITH CLOUDS DISSIPATING EARLIER IN THE SOUTH). WITH THE CWA RETURNING TO A WARM ADVECTION PATTERN...TEMPS WILL RISE AGAIN ON SUNDAY...AND STRUGGLE TO EVEN CROSS BACK UNDER THE FREEZING MARK ON SUNDAY NIGHT / EARLY MONDAY MORNING. && .LONG TERM /MONDAY THROUGH FRIDAY/... RAIN WILL BE LIKELY MONDAY AS A SURGE OF GULF MOISTURE MOVES UP A FRONTAL BOUNDARY ON A SOUTHWEST UPPER FLOW. SOME LOCATIONS MAY SEE AN INCH OF RAIN WITH THIS EVENT. RAIN AND SNOW SHOWERS ARE POSSIBLE FOR TUESDAY IN THE NORTHWEST FLOW BEHIND THE FRONT. SNOW SHOWERS MAY LINGER ON WEDNESDAY IN THE COLDER NORTHWEST FLOW. A PERIOD OF DRY WEATHER IS INDICATED FOR THURSDAY WHEN A RIDGE OF HIGH PRESSURE IS FORECAST TO PUSH ACROSS THE REGION. SNOW SHOWERS WILL BE POSSIBLE AGAIN ON FRIDAY DUE TO A TROUGH AND ASSOCIATED MOISTURE AND COLD ADVECTION. TEMPERATURES WILL START ABOVE NORMAL MONDAY AND TUESDAY...WITH HIGHS MAINLY IN THE 40S. COLD ADVECTION WILL PUSH READINGS BELOW NORMAL ON WEDNESDAY AND FRIDAY WITH HIGHS IN THE 20S...WHILE THE RIDGE WILL PROVIDE SOME WARM ADVECTION AND NEAR NORMAL 30S FOR THURSDAY. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... ABUNDANT LOW LEVEL MOISTURE SHROUDING ILN/S TAFS IN IFR CIGS AND IFR/MVFR VSBYS IN FOG NORTH OF E-W ORIENTED WARM FRONT. LOW CLOUDS AND VSBYS WILL BE SLOW TO IMPROVE THRU THE AFTN. NEXT MID LEVEL TROF TO SHARPEN UP OVER THE PLAINS WITH MID LEVEL FLOW BACKING ACRS THE OHIO VALLEY. FAVORABLE ISENTROPIC LIFT WILL DEVELOP AHD OF THIS SYSTEM DURG THE AFTN. BASED ON LATEST MODEL TRENDS HAVE VCSH DEVELOPING DURG EARLY EVENING AND THEN PREVAILING RAIN DEVELOPING BETWEEN 04Z AND 07Z. EXPECT IFR CIGS WITH MVFR VSBYS DURG RAIN. COLD FRONT EXPECTED TO SWEEP EAST THRU THE TAF SITES DURG EARLY MORNING SATURDAY. WINDS WILL SHIFT TO THE WEST AND GUST UP TO 26 KTS. EXPECT MVFR CIGS TO LINGER THRU SATURDAY AFTN. OUTLOOK...MVFR TO IFR CEILINGS LIKELY THROUGH SATURDAY NIGHT. MVFR VISIBILITIES POSSIBLE INTO EARLY SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...CONIGLIO AVIATION...AR
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
110 PM EST FRI JAN 10 2014 .SYNOPSIS... UPPER TROUGH EXITS EAST BY NOON. TEMPERATURES MODERATING INTO SATURDAY BEFORE COLD FRONT WITH RAIN CROSSES. WEAK HIGH PRESSURE PASSES SUNDAY. COLD FRONTS DUE EARLY AND LATE NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... NO CHANGES. WORKING ON THE AFTERNOON PACKAGE. PREVIOUS DISCUSSION... RADAR IMAGES SHOW A BROAD AREA OF LIGHT PCPN BOUNCING FROM LIGHT RAIN TO MIXED SNOW MAINLY NORTHERN PORTIONS OF SOUTHEAST OH AND NORTHERN EXTREME OF WV. EXPECT THIS AREA TO GRADUALLY MOVE EASTWARD THROUGH THE EARLY MORNING HOURS. PCPN SHOULD BE PUSHED EAST OVER THE EASTERN MOUNTAINS BY MID MORNING LEAVING THE LOWLANDS PCPN FREE...AND DIMINISHING OVER THE MOUNTAINS TOWARDS NOON. THE HIGH RESOLUTION MODEL HRRR HAS THE CLOSER SOLUTION WHEN COMPARED WITH RADAR IMAGES. THE RUC13 LOOKS ABOUT 6 TO 12 HOURS SLOWER THAN ACTUAL WEATHER MOVING THROUGH. ADJUSTED POPS PER LATEST RADAR IMAGES AND THE MATCHING HRRR MODELS THROUGH FRIDAY MORNING. TEMPERATURES ACROSS THE LOWLANDS SLOWLY INCREASING MAKING TRANSITIONING PCPN INTO ALL RAIN. WARM AIR ADVECTION WILL CONTINUE UNDER SOUTHWEST FLOW KEEPING PCPN LIQUID AND BRINGING RELATIVELY WARMER TEMPERATURES COMPARED WITH PREVIOUS DAYS. BELIEVE ONCE RAIN SHOWERS MOVE EAST BY NOON...IT WILL BE A RELATIVELY DRY FRIDAY. HOWEVER...A STRONG COLD FRONT APPROACHES FROM THE WEST LATE TONIGHT...WITH A GOOD CHANCE FOR PCPN AND SOME GUSTY WIND. NOT EXITED ABOUT MODELS SHOWING H85 FLOW ABOUT 50 KNOTS LATER TONIGHT INTO EARLY SATURDAY MORNING. SOUTHWEST FLOW PARALLEL TO THE MOUNTAIN...UPGLIDE NOTICEABLE IN 280K ISENTROPIC CHARTS...AND THE POSSIBILITY OF NIGHT TIME DECOUPLING WILL MAKE THIS STRONG FLOW TO STRUGGLE TO MIX DOWN TO THE SFC TONIGHT. INCREASED ONSET OF PCPN TO CATEGORICAL LATE TONIGHT SPREADING FROM WEST TO EAST. WENT WITH THE MOST REASONABLE MOS CONSENSUS FOR TEMPERATURES THROUGH THE PERIOD. TEMPERATURES OVER THE EASTERN SLOPES COULD REMAIN AT OR BELOW FREEZING ON PROTECTED VALLEYS. THEREFORE...KEPT THE WINTER WEATHER ADVISORY FOR FREEZING RAIN FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 8 AM THIS MORNING. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... PACIFIC COLD FRONT STILL ON TRACK TO SWEEP ACROSS THE FORECAST AREA FROM WEST TO EAST SATURDAY MORNING...WITH ASSOC UPPER TROUGH PROGRESSING NORTHEASTWARD ACROSS THE GREAT LAKES REGION DURING THE DAY ON SATURDAY. STRONG LOW LEVEL WINDS PUSH INTO MAINLY THE WESTERN PARTS OF THE AREA OVERNIGHT FRI NIGHT...WHICH CONTINUE INTO THE SHORT TERM PERIOD EARLY SATURDAY MORNING. 850MB WINDS ARE PROGGED AROUND 70-75KTS ACROSS THE WESTERN ZONES AND NEAR 50KTS AT 925MB. WIND SPEEDS THIS STRONG AT THIS ALTITUDE WITH ASSOC PRECIP ALWAYS BRING SOME CONCERN...AS IT/S TOUGH TO KNOW JUST HOW MUCH PRECIP DRAG WILL BE ABLE TO BRING STRONG WINDS TO THE SURFACE. HOWEVER...WITH A STOUT INVERSION BELOW 900MB AND A TURNING OF WIND DIRECTION IN LOW-LEVELS SHOULD RESULT IN LESS RISK FOR HIGH WINDS AT THE SURFACE VERSUS PREVIOUS EVENTS THIS FALL/WINTER. SPC HAS NOT INCLUDED OUR FORECAST AREA IN A GENERAL RISK. NONETHELESS..SOMETHING TO WATCH EARLY SATURDAY MORNING AS THE PRECIP MOVES ACROSS. ALL IN ALL THOUGH...NOT MUCH CHANGE WITH PREV FORECAST THINKING. CATEGORICAL POPS EVERYWHERE DURING THE MORNING HOURS SATURDAY WITH THE FRONT. HIGH PWATS AROUND AN INCH SHOULD SPELL A FAIRLY QUICK QUARTER TO HALF INCH OF RAIN FOR MOST LOCATIONS...PERHAPS A LITTLE MORE IN THE EASTERN MOUNTAINS. NO HYDRO CONCERNS ARE EXPECTED WITH THIS SYSTEM HOWEVER. CONTINUED PREV FORECAST THINKING WITH REGARD TO A SLIGHT NON-DIURNAL TREND IN TEMPS ON SATURDAY WITH THE WARMEST 850MB/925MB TEMPS OCCURRING OVER WESTERN/CENTRAL AREAS BTWN 15Z-18Z SAT. THE BULK OF THE PRECIP SHOULD BE ALONG AND EAST OF THE I79 CORRIDOR BY 18Z SAT...WITH SYNOPTIC PRECIP WINDING DOWN AREA-WIDE BY 00Z SUN. WILL KEEP INHERITED HIGH CHANCE POPS HOWEVER ALONG THE EASTERN SLOPES A LITTLE LONGER WITH A WESTERLY UPSLOPE FLOW CONTINUING. STILL APPEARS THE STRONGEST WINDS COME LATE SAT AFTERNOON INTO THE EARLY OVERNIGHT HOURS SAT NIGHT POST-FRONT...WITH GUSTS IN THE HIGH COUNTRY TOPPING 40KTS. BY SATURDAY NIGHT ALL LOCATIONS EXCEPT THE EASTERN MOUNTAINS SHOULD BE PRECIP-FREE. HIGHER ELEVATIONS MAY SEE SOME LINGERING LIGHT RAIN OR SNOW SHOWERS THROUGH AROUND THE 06Z-09Z SUN TIME FRAME WITH DEPTH OF LLVL MOISTURE DECREASING...BUT AGAIN...AMOUNTS ARE EXPECTED TO BE VERY LIGHT WITH MOST AREAS PROBABLY ACTUALLY ONLY EXPERIENCING DRIZZLE OR FLURRIES. OVERNIGHT MINS BY EARLY SUN STILL EXPECTED TO BE IN THE LOW/MID 30S MOST LOWLAND LOCATIONS...WITH MID/UPPER 20S FOR THE MOUNTAINS. INITIALLY CLOUDY SKIES DURING THE EARLY OVERNIGHT HOURS SHOULD GRADUALLY BECOME MOSTLY CLEAR TO PARTLY CLOUDY FOR THE LOWLANDS BY DAWN SUNDAY...WITH OF COURSE LINGERING CLOUDS IN THE MOUNTAINS. SUNDAY AND SUNDAY NIGHT...SFC HIGH PRESSURE PASSES TO OUR SOUTH WITH WINDS BACKING FROM THE WEST TO THE SOUTH BY SUNDAY NIGHT. FLOW ALOFT ALSO BACKS FROM NEAR ZONAL TO SOUTHWESTERLY AS THE NEXT UPPER TROUGH DIGS QUICKLY SOUTHEAST INTO THE CENTRAL CONUS. STILL...A NICE PERIOD WITH MOSTLY SUNNY SKIES FOR ALL LOCATIONS IS EXPECTED. CONTINUED TO NUDGE MAX TEMPS UPWARD FOR SUNDAY...AS WAS THE PREVIOUS FORECAST TREND. 850MB/925MB TEMPS SUGGEST LOWLAND LOCATIONS NEAR THE CRW-HTS CORRIDOR APPROACHING 50F DEGREES. WILL RAISE TEMPS GENERALLY TO THE MID/UPPER 40S LOWLANDS...WITH MID 30S ON HIGHEST PEAKS. OVERNIGHT MINS SUNDAY NIGHT/MONDAY MORNING FOR THE LOWLANDS IN THE LOW/MID 30S STILL LOOK ON TRACK. DID RAISE EASTERN MOUNTAIN MINS UP AND ALSO CODED UP A NON-DIURNAL TEMP CURVE HERE...WITH DECENT 850MB WARM ADVECTION NOTED ON CONSENSUS OF MODEL OUTPUT IT APPEARS THAT THE MIN TEMP WILL BE REALIZED CLOSE TO MIDNIGHT FOR LOCATIONS SUCH AS SNOW WITH TEMPS CONTINUING A SLOW RISE TOWARDS DAWN MONDAY. && .LONG TERM /MONDAY THROUGH THURSDAY/... HIGH PRESSURE OF THE SE US WILL BRING A DRY START TO THE LONG TERM PERIOD. THERE IS POOR AGREEMENT BETWEEN THE ECMWF AND GFS ON SYSTEM ARRIVING LATE MONDAY. BOTH INDICATE A FRONTAL PASSAGE...BUT THE ECMWF ALSO SHOWS A SURFACE WAVE RIDING THE FRONT OUT OF THE SE...NORTHEAST JUST EAST OF THE APPALACHIANS. THE GFS DOES NOT HAVE THIS...AND IS INSTEAD JUST A COLD FRONTAL PASSAGE CONNECTED TO A SURFACE LOW NORTH OF THE GREAT LAKES. TRENDED TOWARD THE ECMWF...WHICH MESHES WELL WITH LATEST WPC GUIDANCE TOO. HAVE CHANCE POPS ACROSS WV ZONES WITH THE FRONT/SURFACE WAVE...SLIDE THOSE OUT TUESDAY. 500MB SHORTWAVE TROUGH PASSES WITH THE FRONT...WITH LARGER SCALE TROUGH ARRIVING MIDWEEK...BRINGING AN INCREASE IN POPS AGAIN TUESDAY NIGHT INTO WEDNESDAY. && .AVIATION /17Z FRIDAY THROUGH TUESDAY/... WITH THE ATMOSPHERE DRYING OUT...SOUTHEAST FLOW AT THE SURFACE WILL ALLOW FOR DOWNSLOPING AND LIFTING OF THE CEILINGS TO VFR LATER THIS AFTERNOON AND EVENING. KEEPING THE TERMINALS DRY PER MODEL GUIDANCE AHEAD OF THE STRONG COLD FRONT EXPECTED AFTER 06Z SATURDAY. WITH THE NATURE OF THE COLD FRONT BEING A CLEAN SWEEP TYPE FEATURE THAT WILL BARREL THROUGH THE CWA...DO NOT THINK THE CEILINGS WILL GO DOWN TO IFR WITH THE FRONTAL PASSAGE. THE LOWEST CONFIDENCE WILL COME IN FOR BKW STRICTLY FOR BEING A HIGHER ELEVATION AND NOT IN A PROTECTED VALLEY. KEEP THAT TAF CONSERVATIVE FOR NOW. VISIBILITIES COULD DROP TO IFR IN SHOWERS...BUT AGAIN...WITH THE COLD FRONT PLOWING THROUGH AND NOT GETTING HELD UP BY THE MOUNTAINS...THE LOW VISIBILITIES SHOULD EXIT WITH THE COLD FRONT. WINDS WILL INCREASE OUT OF THE SOUTH AHEAD OF THE FRONT WITH GUSTS HITTING THE 15KT TO 25KT RANGE. AFTER PASSAGE OF THE COLD FRONT...EXPECT THE WINDS TO TURN SOUTHWESTERLY WITH GUSTS PERSISTING TO 25KTS. MAY NEED TO ADD TEMPO GROUPS WITH THE COLD FRONT AS SHOWERS BRING DOWN GUSTIER WINDS ALOFT FOR AN HOUR OR TWO. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SATURDAY... FORECAST CONFIDENCE: HIGH TODAY. MEDIUM TONIGHT. ALTERNATE SCENARIOS: MAY NEED HIGHER WINDS BEFORE...WITH...AND AFTER THE FRONT. TIMING ISSUES MAY ONLY BE MINOR...WITHIN A COUPLE HOURS. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY H H M M M M M M H H H H HTS CONSISTENCY H H H M H H L L M H H H BKW CONSISTENCY M H H H H L L L L L L L EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H L L H H H L CKB CONSISTENCY H H H H H H L L H H H H AFTER 18Z SATURDAY... IFR CONDITIONS IN RAIN COULD DEVELOP SATURDAY INTO SUNDAY IN STRONG FLOW ALOFT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/50 NEAR TERM...ARJ/26 SHORT TERM...50 LONG TERM...MZ AVIATION...26
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
206 PM CST FRI JAN 10 2014 .SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT) ISSUED AT 206 PM CST FRI JAN 10 2014 MAIN CONCERNS IN THE SHORT TERM WILL BE DEALING WITH WINTRY MIX INTO TONIGHT. A WINTER WEATHER ADVISORY IS IN EFFECT UNTIL 6 AM SATURDAY. WATER VAPOR IMAGERY SHOWING A DEEP MID-LEVEL TROUGH MOVING ACROSS CENTRAL CONUS AT THIS TIME. AT THE SURFACE...A TROUGH EXTENDED FROM ALONG THE DAKOTAS/MN BORDER...INTO EASTERN NEBRASKA/KANSAS. THESE FEATURES WERE PRODUCING ISENTROPIC LIFT AND MOISTURE TRANSPORT INTO THE AREA FOR A WINTRY MIX OF PRECIPITATION AT GROUND LEVEL. RADAR SHOWING RETURNS ACROSS THE ENTIRE AREA WITH AREAS OF MAINLY DRIZZLE AND FREEZING DRIZZLE BEING REPORTED. SOME SLEET WAS ALSO SHOWING UP ACROSS PARTS OF NORTHEAST IA. OTHERWISE...TEMPERATURES ACROSS THE AREA RANGED FROM THE MIDDLE 20S ACROSS NORTH CENTRAL WI...TO THE LOWER 30S ACROSS NORTHEAST IA INTO FAR SOUTHWEST WI. LOOK FOR THE MID-LEVEL/SURFACE TROUGH TO MOVE EAST THROUGH THE AREA TONIGHT...WITH MOST OF THE PRECIPITATION CHANGING OVER TO LIGHT SNOW THIS EVENING. THE ONLY EXCEPTION WILL BE ACROSS PORTIONS OF NORTHEAST IA INTO FAR SOUTHWEST AND CENTRAL WI WHERE THERE WILL BE LACK OF ICE ISSUES IN THE COLUMN AND WARMER AIR ALOFT. SO...A MIXTURE OF DRIZZLE...FREEZING DRIZZLE...SLEET AND LIGHT SNOW WILL STILL BE POSSIBLE THERE. WHERE THE SNOW FALLS...GENERALLY ALONG AND NORTHWEST OF A TOMAH/LA CROSSE/OELWEIN LINE...PERHAPS 1/2-1 INCH IS POSSIBLE. OF NOTE IS THE RAP SHOWING LOSS OF ICE IN THE CLOUD AGAIN AFTER MIDNIGHT...HINTING AT THE POSSIBILITY OF MIXING WITH OR CHANGING OVER TO LIGHT FREEZING DRIZZLE OVERNIGHT. WITH THIS IN MIND...WILL KEEP WINTER WEATHER ADVISORY GOING THROUGH 6 AM SATURDAY. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE 20S. MAY STILL BE SOME LIGHT SNOW/FLURRY ACTIVITY EARLY ON SATURDAY MORNING...BUT LOOKING FOR ANY LINGERING PRECIPITATION TO SHIFT OFF TO THE EAST BY NOON AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE PLAINS. AREAS WEST OF THE MISSISSIPPI WILL LIKELY SEE A GOOD AMOUNT OF SUNSHINE BY AFTERNOON WITH CLEARING PUSHING EAST OF THE MISSISSIPPI LATER IN THE AFTERNOON. HIGHS ON SATURDAY EXPECTED TO RISE INTO THE UPPER 20S TO LOWER 30S. RIDGE OF HIGH PRESSURE WILL CONTINUE TO MOVE EAST ACROSS THE AREA SATURDAY NIGHT FOR QUIET WEATHER CONDITIONS. WILL SEE SOME INCREASE IN MID/HIGH LEVEL CLOUDS THOUGH AHEAD OF A WARM FRONT PUSHING EAST OUT OF THE NORTHERN/CENTRAL PLAINS. OVERNIGHT LOWS WILL BE IN THE LOWER TO MIDDLE TEENS. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 206 PM CST FRI JAN 10 2014 MILDER PACIFIC ORIGIN AIR WILL PUSH INTO THE AREA ON SUNDAY WITH HIGHS EXPECTED TO TOP OFF IN THE LOWER/MIDDLE 30S. UNFORTUNATELY... INCREASING CLOUD COVER AND SOUTHWEST WINDS IN THE 10 TO 20 MPH RANGE WILL MAKE IT FEEL MORE LIKE THE LOWER/MIDDLE 20S. A COLD FRONT WILL THEN PUSH INTO/THROUGH THE AREA SUNDAY NIGHT. THIS WILL GIVE THE AREA A CHANCE OF A WINTRY MIX WITH A TRICKY THERMAL PROFILE IN PLACE. COLDER AIR UNDERCUTTING RELATIVELY MILDER AIR ALOFT MAY PRODUCE A LIGHT WINTRY MIX OF FREEZING RAIN/SLEET/SNOW AS OVERNIGHT LOWS FALL INTO THE TEENS/LOWER 20S. FORTUNATELY... PRECIPITATION LOOKS VERY LIGHT...BUT ANY FREEZING PRECIPITATION COULD CAUSE HEADACHES. WILL CONTINUE TO TO KEEP A CLOSE EYE ON THIS. COLDER AIR WILL FILTER INTO AREA MONDAY THROUGH TUESDAY AS A DEEP MID-LEVEL TROUGH CARVES OUT OVER THE CENTRAL CONUS. SOME EMBEDDED ENERGY WITHIN THE TROUGH WILL GIVE THE AREA A CHANCE FOR LIGHT SNOW AS WELL. LOOK FOR HIGHS MONDAY AND TUESDAY IN THE 20S WITH LOWS MONDAY NIGHT IN THE UPPER SINGLE DIGITS AND TEENS. ANOTHER SHOT AT SOME LIGHT SNOW LOOKS TO OCCUR WEDNESDAY NIGHT INTO THURSDAY AS WARM AIR ADVECTION TAKES PLACE AHEAD OF LOW PRESSURE MOVING ACROSS SOUTHERN CANADA. SOME LINGERING LIGHT SNOW OF FLURRY CHANCES WILL BE SEEN THURSDAY NIGHT AS THE COLD FRONT FROM THIS LOW PASSES THROUGH. MUCH COLDER AIR IS ON TAP GOING INTO FRIDAY AS ANOTHER MODIFIED SHOT OF ARCTIC AIR MAKES ITS WAY INTO THE AREA. HIGHS ARE EXPECTED TO DROP BACK INTO THE TEENS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1135 AM CST FRI JAN 10 2014 WIDESPREAD IFR CONDITIONS PREVAIL ACROSS THE REGION AND NOT EXPECTING MUCH CHANGE TO OCCUR UNTIL A COLD FRONT MOVES ACROSS THE REGION OVERNIGHT. SOME LIGHT FREEZING DRIZZLE OCCURRING WITH THE LOW CLOUDS AND FOG AND THIS WILL REMAIN A POSSIBILITY THROUGH ABOUT THE MIDDLE OF THE AFTERNOON. LOOKS LIKE ICE WILL THEN BE INTRODUCED IN THE CLOUDS TO ALLOW THE FREEZING DRIZZLE TO CHANGE OVER TO LIGHT SNOW. THIS SNOW SHOULD THEN CONTINUE UNTIL THE FRONT COMES THROUGH SWINGING THE WINDS AROUND TO THE WEST/NORTHWEST. SATELLITE CURRENTLY INDICATING SOME CLEARING OCCURRING BEHIND THE FRONT OVER THE DAKOTAS AND THE BUFKIT SOUNDINGS FROM THE 10.12Z NAM SUGGEST THIS COULD OCCUR LATE TONIGHT AS WELL. WILL TREND TOWARD THIS TAKING THE IFR CONDITIONS OUT LATE TONIGHT AND GO TO A HIGH VFR CEILING WHILE HOLDING ONTO A BIT OF FOG UNTIL THE WIND CAN COME UP ENOUGH TO MIX THINGS OUT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR WIZ017-029- 034-041>044-053>055-061. MN...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR MNZ096. IA...WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR IAZ010-011- 029-030. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...04