Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 02/04/16


AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
307 AM CST TUE FEB 2 2016 .UPDATE... 830 PM CST FOR EVENING UPDATE... HAD UPDATED EARLIER TO ISSUED DENSE FOG ADVISORY FOR MUCH OF NORTHERN IL WEST OF CHICAGO. 11-3.9 MICRON IR IMAGERY INDICATES EASTWARD DRIFT OF FOG/LOW STRATUS HAS SLOWED OR NEARLY STOPPED ROUGHLY ALONG A ROUND LAKE TO PLAINFIELD TO COAL CITY LINE. INTERESTINGLY...KLOT 88D SHOWS A DIFFUSE AREA OF WEAK REFLECTIVITY RETURNS IN THIS SAME AREA AT ROUGHLY 400-700 FT AGL...WHICH IS LIKELY THE RADAR SAMPLING THE EASTERN EDGE OF THE SHARP INVERSION NOTED IN THE DVN 00Z RAOB. A RECENT AMDAR ASCENT SOUNDING OUT OF KMDW INDICATES WINDS TURNING NORTHEAST 10-15 KT AT 800-1000 FT AND THINKING CONTINUES TO BE THAT FOG/LOW STRATUS WILL BEGIN TO ERODE BACK TO THE WEST THROUGH LATE EVENING AS LOW LEVEL SYNOPTIC WIND FIELD BEGINS TO FEEL THE INFLUENCE OF THE SURFACE LOW OVER THE SOUTHERN PLAINS. PLAN IS TO MAINTAIN THE DENSE FOG ADVISORY AS IS AT THIS TIME AND MONITOR EVOLUTION...TRIMMING COUNTIES FROM EAST TO WEST LATER TONIGHT AS CONDITIONS IMPROVE LATER TONIGHT WITH INCREASING EAST-NORTHEAST WINDS. IN ADDITION...CURRENT/RECENT HIGH-RES GUIDANCE APPEARS TO BE TRENDING WEAKER WITH INITIAL WEAK F-GEN FORCED PRECIP BAND WHICH WOULD AFFECT NORTH CENTRAL IL LATER TONIGHT...AND WHILE WILL MAINTAIN POPS WILL LOWER AND SLOW THEIR ARRIVAL A BIT AFTER MIDNIGHT. RATZER && .SHORT TERM... 319 PM CST THROUGH WEDNESDAY NIGHT... THE UPCOMING STORM WAS FOCUSED ON TODAY WITH THE CONFIDENCE TO REFINE TIMING DETAILS. THAT WAS THE PRIMARY ADJUSTMENT WITH THE FORECAST. APART FROM AREAS NORTH OF I-88...THE PRECIPITATION DOES NOT LOOK TO BEGIN UNTIL AFTER MOST...IF NOT ALL...OF THE TUESDAY A.M. COMMUTE. THIS WILL KEEP MIXED PRECIPITATION AND SNOW CHANCES LATE TONIGHT AND TUESDAY MORNING ALSO CONFINED TO MAINLY THE NORTH AS WELL. NO SPECIAL WEATHER STATEMENT IS PLANNED AT THIS TIME AS IT LOOKS LIKE BETTER CHANCES/LONGER DURATION MAY REMAIN NORTH OF THE BORDER. HAVE ALSO BUMPED UP RAINFALL AMOUNTS ON TUESDAY TO BETWEEN 0.50 TO 0.80 FOR MUCH OF THE CWA WITH A STRONGER SIGNAL OF INSTABILITY...AND HAVE ALSO INCREASED THUNDER CHANCES. THE SEVERE POTENTIAL CONTINUES TO LOOK LIKE IT WILL POSSIBLY CLIP THE SOUTHEAST CWA /SOUTH OF U.S. HIGHWAY 24/ DURING TUESDAY AFTERNOON. CHANCES INCREASE MARKEDLY FURTHER DOWNSTATE INDIANA. THE AREA OF FOG WHICH HAD BEEN PRESENT ACROSS NORTH CENTRAL AND NORTHWEST ILLINOIS HAS EASED BUT THE STRATUS REMAINS. TEMPERATURES ARE RIGHT AROUND FREEZING UNDER THIS CLOUD LAYER WHICH IMPLIES THEY WILL DIP A FEW DEGREES BELOW FREEZING TONIGHT AS AN EASTERLY WIND WILL NOT OFFER ANY SURFACE WARM ADVECTION. WARM ADVECTION ALOFT WILL GRADUALLY DEVELOP LATE THIS EVENING AND OVERNIGHT THOUGH THE MOIST ADVECTION WILL LAG THAT. FORCING FOR PRECIPITATION OVERNIGHT IN MODEL SPATIAL AND CROSS SECTION OUTPUT CONTINUES TO BE TIED TO THE TIGHTENING MID-LEVEL BAROCLINIC ZONE NEAR THE IL/WI STATE LINE WHERE ENOUGH INDUCED LIFT FOR SATURATION WILL BE PRESENT. OUTSIDE OF THAT THE PROFILES APPEAR TOO DRY AND INCOMING HIGH-RESOLUTION MODELS SUPPORT THIS...INCLUDING INTO THE 6-9 A.M. TIME FRAME. MOST OF THE MODELS DO NOT PROVIDE MUCH QPF THOUGH FOR THE NORTHERN CWA THROUGH THE MORNING...AND NOT SEEING A WEAKENING OF STATIC STABILITY PROGGED EITHER. SO CONTINUE TO KEEP ONLY CHANCES IN THE FAR NORTH THROUGH EARLY MORNING...WITH PROFILES SUPPORTIVE OF A SNOW...POSSIBLY A SNOW/SLEET MIX. AS PRECIPITATION INTENSITY RAPIDLY INCREASES DURING THE MID-LATE MORNING...PROFILES COULD DIABATICALLY COOL SOME...BUT THAT WILL BE OFFSET WITH ELEVATED WARM ADVECTION. THIS COULD CONTINUE A MIX OF SNOW OR SLEET WITH RAIN IN AND AROUND THE ROCKFORD/BELVIDERE AREAS THROUGH THE MORNING. BECAUSE SURFACE TEMPERATURES ARE STARTING TONIGHT A BIT COOLER...IT COULD RESULT IN THEM BEING COOLER INTO THE MORNING AND THUS THE FREEZING RAIN CHANCE PERSISTS THROUGH THE MORNING TOO. SO MINOR SNOW AND/OR ICING REMAINS POSSIBLE. THIS WILL CONTINUE TO BE ASSESSED AND IF A STATEMENT IS NEEDED THE EVENING OR OVERNIGHT SHIFT WILL ISSUE. MODELS CONTINUE WITH THE EVER SO SLIGHTLY NORTHWEST TRACK OF THE LOW PRESSURE ON TUESDAY AND EVER SO SLOWER...WHICH RESULTS IN DEEPER MOISTURE AND MORE INSTABILITY OVER THE AREA. THE UPPER LOW MAINTAINS A DEFINITE CLOSED SIGNATURE WITH A SLIGHT NEGATIVE TILT INTO TUESDAY AFTERNOON...LIKELY CENTERED NEAR OMAHA OR SO. DEEP QG FORCING AND ROBUST MOIST ADVECTION AHEAD OF THIS...WITH PWATS NEAR/AT RECORD FOR EARLY FEBRUARY...SHOULD BLOSSOM MODERATE TO EVEN HEAVY RAIN LATE IN THE MORNING THROUGH MID-AFTERNOON AREAWIDE. STEEPER LAPSE RATES AND ELEVATED INSTABILITY WRAPPED NORTHWARD LOOK TO PROVIDE SCATTERED EMBEDDED THUNDERSTORMS ACROSS THE AREA IN THAT TIME WHICH COULD FURTHER INCREASE RAIN RATES. AN AXIS OF LOW-LEVEL DEW POINTS IN THE MID 50S LOOKS TO REACH THE FAR SOUTHEAST CWA JUST AHEAD OF THE PACIFIC COOL FRONT. CLIMATOLOGICALLY FOR COOL SEASON SEVERE WEATHER IN THE CWA THOSE DEW POINTS ARE A TAD LOW FOR SURFACE BASED CONVECTION...BUT WILL STILL NEED TO WATCH CLOSELY AS DEW POINTS/INSTABILITY CAN OUTPERFORM AND THE SHEAR OBVIOUSLY IS PLENTIFUL. TEMPERATURES LOOK TO PEAK MID 50S TO POSSIBLY LOWER 60S FAR SOUTHEAST CWA TO ONLY THE MID TO UPPER 30S IN THE NORTHWEST...WITH MUCH OF THE MIDDLE AREA AND CHICAGO KEPT IN THE LOWER 40S DUE TO HEAVIER RAIN INTENSITY AND A STRONG SURFACE EASTERLY WIND. THE SYSTEM DRY SLOT LOOKS TO SHUT DOWN STEADIER RAIN AND LIKELY EVEN END IT FOR MUCH OF THE CWA FOR A GOOD PART OF TUESDAY NIGHT...ESPECIALLY WITH THE MORE NORTHERLY TRACK. WHILE MODELS DIVERGE A LITTLE ON HOW THE UPPER WAVE LIFTS INTO/PHASES INTO THE NORTHERN STREAM...THERE CONTINUES TO BE A SIGNAL FOR LIGHT PRECIPITATION ON WEDNESDAY MORNING AND EVEN EARLY-MID AFTERNOON...ESPECIALLY FOR ALONG/NORTH OF I-80. WITH THE OVERALL SLOWER PROGRESS...THE LOW-LEVEL COLD ADVECTION LAGS SO SOME OF THIS PRECIPITATION MAY STILL BE RAIN. BUT DO EXPECT TO SEE SOME LIGHT SNOW. PROFILES ARE NOT SUPPORTIVE OF GOOD RATIOS SO JUST HAVE A FEW TENTHS OF ACCUMULATION FORECAST WITH THAT. MTF && .LONG TERM... 300 PM CST THURSDAY THROUGH MONDAY... RISING HEIGHTS ALOFT...AND A PERSISTENT WEST-SOUTHWESTERLY SURFACE FLOW...WILL ALLOW FOR A DECENT WARMING TREND INTO THE WEEKEND...BEFORE COLDER AIR BEGINS TO RETURN TO THE AREA NEXT WEEK. A FAIRLY PROGRESSIVE UPPER LEVEL PATTERN OVER THE CONUS WILL ALLOW THE COLDER AIRMASS...AND THE NORTHWESTERLY UPPER LEVEL FLOW DURING THE SHORT TERM PERIOD TO SHIFT OUT OF THE AREA BY LATE WEEK. AN INCREASE IN WEST-SOUTHWESTERLY LOW LEVEL FLOW...IN ASSOCIATION WITH HIGH PRESSURE OVER THE SOUTHERN CONUS...AND A COUPLE OF CLIPPER SYSTEMS OVER THE UPPER GREAT LAKES AND SOUTHERN CANADA...WILL HELP TRANSPORT WARMER TEMPERATURES OVER THE REGION FOR THE WEEKEND. OVERALL...IT APPEARS THAT MOST OF THE AREA COULD BE IN THE 40S...ESPECIALLY BY SUNDAY...WITH UPPER 40S TO NEAR 50 POSSIBLE SOUTH. OVERALL...PRECIPITATION CHANCES LOOK MEAGER OVER THE AREA...UNTIL POSSIBLY EARLY NEXT WEEK. DURING THIS PERIOD...MODEL AND ENSEMBLE GUIDANCE ARE IN GOOD AGREEMENT THAT A HIGH LATITUDE RIDGE WILL DEVELOP OVER THE WEST COAST...POSSIBLE EXTENDING UP INTO THE ARCTIC OCEAN. THIS PATTERN WOULD FAVOR A SIGNIFICANT TROUGH AND A MUCH COLDER ARCTIC AIRMASS TO SPILL SOUTHWARD OVER MUCH OF THE CENTRAL CONUS NEXT WEEK. CURRENTLY IT APPEARS THE COLDEST AIRMASS MIGHT NOT ARRIVE UNTIL TUESDAY OR WEDNESDAY OF NEXT WEEK...WHICH IS BEYOND THE CURRENT FORECAST PERIOD. HOWEVER...AS THIS COLD AIR BEGINS TO FILTER INTO THE AREA EARLY NEXT WEEK...A PERIOD OF SNOW SHOWERS WILL BE POSSIBLE. KJB && .AVIATION... 1130 PM CST STRATUS AND VSBY ARE FINALLY IMPROVING WITH ALL TAF SITES AT MVFR OR BETTER. EXPECTING CONDITIONS TO CONTINUE TO IMPROVE ESPECIALLY AS EAST WINDS INCREASE OVERNIGHT. GUSTY EAST WINDS DEVELOP BY THE EARLY MORNING HOURS AND MAX GUSTS AROUND 30 KT ARE EXPECTED THROUGH THE LATE MORNING AND AFTERNOON. PUSHED BACK THE TIMING OF PRECIP AS GUIDANCE CONTINUES TO SLOW THE SYSTEM/S PROGRESSION. RFD MAY SEE A BRIEF PERIOD OF SNOW EARLY THIS MORNING. EXPECTING RAIN TO SPREAD ACROSS THE TERMINALS IN THE LATE MORNING WITH MVFR CIGS. RAIN INTENSITY WILL INCREASE IN THE EARLY AFTN RESULTING IN IFR VSBYS. EMBEDDED THUNDER IS ALSO EXPECTED IN THE AFTERNOON WITH 1SM VSBY PSBL WITH THE STORMS. SOME STORMS COULD BE SEVERE. GUIDANCE THEN INDICATES THAT IFR TO LIFR CIGS WILL ARRIVE IN THE MID AFTN. WE ENTER THE DRY SECTOR OF THE SYSTEM THIS EVENING WITH SHOWERS ENDING AND WINDS BECOMING SOUTH. CIGS SHOULD BECOME VFR. WINDS BECOME WEST BEHIND THE COLD FRONT AND GUST TO 30 KT. SOME GUIDANCE MEMBERS FEATURE IFR CIGS...BUT ONLY HAVE MEDIUM-LOW CONFIDENCE IN THEM SO WENT WITH A SCT IFR GROUP FOR NOW. HAVE HIGH CONFIDENCE IN PRECIP TRENDS AND GUSTY EAST WINDS...MEDIUM- HIGH CONFIDENCE IN PRECIP TIMING...MEDIUM CONFIDENCE IN TSRA AND CIGS...LOW CONFIDENCE IN VSBY VALUES. JEE && .MARINE... 306 AM CST A STRONG LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS IS PROGGED TO LIFT NORTHEAST ACROSS LAKE MICHIGAN OVERNIGHT TONIGHT. OUT AHEAD OF THE LOW...EASTERLY WINDS ARE EXPECTED TO INCREASE TO GALE FORCE ACROSS LAKE MICHIGAN. THE LOW WILL MOVE ACROSS THE LAKE AFTER MIDNIGHT WITH NORTHEAST WINDS NORTH OF THE LOW AND SOUTH TO SOUTHWEST WINDS SOUTH OF THE LOW TRACK LATE TONIGHT INTO EARLY WEDNESDAY. AS THE LOW DEPARTS ON WEDNESDAY...WINDS WILL BECOME NORTHWEST ACROSS THE ENTIRE LAKE GUSTING TO AROUND 30 KT. A SERIES OF WEAKER WAVES WILL MOVE ACROSS THE GREAT LAKES LATE IN THE WEEK THROUGH THE WEEKEND RESULTING IN ADDITIONAL UNDULATIONS IN THE WIND SPEEDS AND DIRECTIONS...BUT FOR NOW NO ADDITIONAL GALES ARE EXPECTED. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...GALE WARNING...LMZ777-LMZ779...9 AM TUESDAY TO 9 PM TUESDAY. GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...9 AM TUESDAY TO 6 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1141 PM CST MON FEB 1 2016 .UPDATE... 830 PM CST FOR EVENING UPDATE... HAD UPDATED EARLIER TO ISSUED DENSE FOG ADVISORY FOR MUCH OF NORTHERN IL WEST OF CHICAGO. 11-3.9 MICRON IR IMAGERY INDICATES EASTWARD DRIFT OF FOG/LOW STRATUS HAS SLOWED OR NEARLY STOPPED ROUGHLY ALONG A ROUND LAKE TO PLAINFIELD TO COAL CITY LINE. INTERESTINGLY...KLOT 88D SHOWS A DIFFUSE AREA OF WEAK REFLECTIVITY RETURNS IN THIS SAME AREA AT ROUGHLY 400-700 FT AGL...WHICH IS LIKELY THE RADAR SAMPLING THE EASTERN EDGE OF THE SHARP INVERSION NOTED IN THE DVN 00Z RAOB. A RECENT AMDAR ASCENT SOUNDING OUT OF KMDW INDICATES WINDS TURNING NORTHEAST 10-15 KT AT 800-1000 FT AND THINKING CONTINUES TO BE THAT FOG/LOW STRATUS WILL BEGIN TO ERODE BACK TO THE WEST THROUGH LATE EVENING AS LOW LEVEL SYNOPTIC WIND FIELD BEGINS TO FEEL THE INFLUENCE OF THE SURFACE LOW OVER THE SOUTHERN PLAINS. PLAN IS TO MAINTAIN THE DENSE FOG ADVISORY AS IS AT THIS TIME AND MONITOR EVOLUTION...TRIMMING COUNTIES FROM EAST TO WEST LATER TONIGHT AS CONDITIONS IMPROVE LATER TONIGHT WITH INCREASING EAST-NORTHEAST WINDS. IN ADDITION...CURRENT/RECENT HIGH-RES GUIDANCE APPEARS TO BE TRENDING WEAKER WITH INITIAL WEAK F-GEN FORCED PRECIP BAND WHICH WOULD AFFECT NORTH CENTRAL IL LATER TONIGHT...AND WHILE WILL MAINTAIN POPS WILL LOWER AND SLOW THEIR ARRIVAL A BIT AFTER MIDNIGHT. RATZER && .SHORT TERM... 319 PM CST THROUGH WEDNESDAY NIGHT... THE UPCOMING STORM WAS FOCUSED ON TODAY WITH THE CONFIDENCE TO REFINE TIMING DETAILS. THAT WAS THE PRIMARY ADJUSTMENT WITH THE FORECAST. APART FROM AREAS NORTH OF I-88...THE PRECIPITATION DOES NOT LOOK TO BEGIN UNTIL AFTER MOST...IF NOT ALL...OF THE TUESDAY A.M. COMMUTE. THIS WILL KEEP MIXED PRECIPITATION AND SNOW CHANCES LATE TONIGHT AND TUESDAY MORNING ALSO CONFINED TO MAINLY THE NORTH AS WELL. NO SPECIAL WEATHER STATEMENT IS PLANNED AT THIS TIME AS IT LOOKS LIKE BETTER CHANCES/LONGER DURATION MAY REMAIN NORTH OF THE BORDER. HAVE ALSO BUMPED UP RAINFALL AMOUNTS ON TUESDAY TO BETWEEN 0.50 TO 0.80 FOR MUCH OF THE CWA WITH A STRONGER SIGNAL OF INSTABILITY...AND HAVE ALSO INCREASED THUNDER CHANCES. THE SEVERE POTENTIAL CONTINUES TO LOOK LIKE IT WILL POSSIBLY CLIP THE SOUTHEAST CWA /SOUTH OF U.S. HIGHWAY 24/ DURING TUESDAY AFTERNOON. CHANCES INCREASE MARKEDLY FURTHER DOWNSTATE INDIANA. THE AREA OF FOG WHICH HAD BEEN PRESENT ACROSS NORTH CENTRAL AND NORTHWEST ILLINOIS HAS EASED BUT THE STRATUS REMAINS. TEMPERATURES ARE RIGHT AROUND FREEZING UNDER THIS CLOUD LAYER WHICH IMPLIES THEY WILL DIP A FEW DEGREES BELOW FREEZING TONIGHT AS AN EASTERLY WIND WILL NOT OFFER ANY SURFACE WARM ADVECTION. WARM ADVECTION ALOFT WILL GRADUALLY DEVELOP LATE THIS EVENING AND OVERNIGHT THOUGH THE MOIST ADVECTION WILL LAG THAT. FORCING FOR PRECIPITATION OVERNIGHT IN MODEL SPATIAL AND CROSS SECTION OUTPUT CONTINUES TO BE TIED TO THE TIGHTENING MID-LEVEL BAROCLINIC ZONE NEAR THE IL/WI STATE LINE WHERE ENOUGH INDUCED LIFT FOR SATURATION WILL BE PRESENT. OUTSIDE OF THAT THE PROFILES APPEAR TOO DRY AND INCOMING HIGH-RESOLUTION MODELS SUPPORT THIS...INCLUDING INTO THE 6-9 A.M. TIME FRAME. MOST OF THE MODELS DO NOT PROVIDE MUCH QPF THOUGH FOR THE NORTHERN CWA THROUGH THE MORNING...AND NOT SEEING A WEAKENING OF STATIC STABILITY PROGGED EITHER. SO CONTINUE TO KEEP ONLY CHANCES IN THE FAR NORTH THROUGH EARLY MORNING...WITH PROFILES SUPPORTIVE OF A SNOW...POSSIBLY A SNOW/SLEET MIX. AS PRECIPITATION INTENSITY RAPIDLY INCREASES DURING THE MID-LATE MORNING...PROFILES COULD DIABATICALLY COOL SOME...BUT THAT WILL BE OFFSET WITH ELEVATED WARM ADVECTION. THIS COULD CONTINUE A MIX OF SNOW OR SLEET WITH RAIN IN AND AROUND THE ROCKFORD/BELVIDERE AREAS THROUGH THE MORNING. BECAUSE SURFACE TEMPERATURES ARE STARTING TONIGHT A BIT COOLER...IT COULD RESULT IN THEM BEING COOLER INTO THE MORNING AND THUS THE FREEZING RAIN CHANCE PERSISTS THROUGH THE MORNING TOO. SO MINOR SNOW AND/OR ICING REMAINS POSSIBLE. THIS WILL CONTINUE TO BE ASSESSED AND IF A STATEMENT IS NEEDED THE EVENING OR OVERNIGHT SHIFT WILL ISSUE. MODELS CONTINUE WITH THE EVER SO SLIGHTLY NORTHWEST TRACK OF THE LOW PRESSURE ON TUESDAY AND EVER SO SLOWER...WHICH RESULTS IN DEEPER MOISTURE AND MORE INSTABILITY OVER THE AREA. THE UPPER LOW MAINTAINS A DEFINITE CLOSED SIGNATURE WITH A SLIGHT NEGATIVE TILT INTO TUESDAY AFTERNOON...LIKELY CENTERED NEAR OMAHA OR SO. DEEP QG FORCING AND ROBUST MOIST ADVECTION AHEAD OF THIS...WITH PWATS NEAR/AT RECORD FOR EARLY FEBRUARY...SHOULD BLOSSOM MODERATE TO EVEN HEAVY RAIN LATE IN THE MORNING THROUGH MID-AFTERNOON AREAWIDE. STEEPER LAPSE RATES AND ELEVATED INSTABILITY WRAPPED NORTHWARD LOOK TO PROVIDE SCATTERED EMBEDDED THUNDERSTORMS ACROSS THE AREA IN THAT TIME WHICH COULD FURTHER INCREASE RAIN RATES. AN AXIS OF LOW-LEVEL DEW POINTS IN THE MID 50S LOOKS TO REACH THE FAR SOUTHEAST CWA JUST AHEAD OF THE PACIFIC COOL FRONT. CLIMATOLOGICALLY FOR COOL SEASON SEVERE WEATHER IN THE CWA THOSE DEW POINTS ARE A TAD LOW FOR SURFACE BASED CONVECTION...BUT WILL STILL NEED TO WATCH CLOSELY AS DEW POINTS/INSTABILITY CAN OUTPERFORM AND THE SHEAR OBVIOUSLY IS PLENTIFUL. TEMPERATURES LOOK TO PEAK MID 50S TO POSSIBLY LOWER 60S FAR SOUTHEAST CWA TO ONLY THE MID TO UPPER 30S IN THE NORTHWEST...WITH MUCH OF THE MIDDLE AREA AND CHICAGO KEPT IN THE LOWER 40S DUE TO HEAVIER RAIN INTENSITY AND A STRONG SURFACE EASTERLY WIND. THE SYSTEM DRY SLOT LOOKS TO SHUT DOWN STEADIER RAIN AND LIKELY EVEN END IT FOR MUCH OF THE CWA FOR A GOOD PART OF TUESDAY NIGHT...ESPECIALLY WITH THE MORE NORTHERLY TRACK. WHILE MODELS DIVERGE A LITTLE ON HOW THE UPPER WAVE LIFTS INTO/PHASES INTO THE NORTHERN STREAM...THERE CONTINUES TO BE A SIGNAL FOR LIGHT PRECIPITATION ON WEDNESDAY MORNING AND EVEN EARLY-MID AFTERNOON...ESPECIALLY FOR ALONG/NORTH OF I-80. WITH THE OVERALL SLOWER PROGRESS...THE LOW-LEVEL COLD ADVECTION LAGS SO SOME OF THIS PRECIPITATION MAY STILL BE RAIN. BUT DO EXPECT TO SEE SOME LIGHT SNOW. PROFILES ARE NOT SUPPORTIVE OF GOOD RATIOS SO JUST HAVE A FEW TENTHS OF ACCUMULATION FORECAST WITH THAT. MTF && .LONG TERM... 300 PM CST THURSDAY THROUGH MONDAY... RISING HEIGHTS ALOFT...AND A PERSISTENT WEST-SOUTHWESTERLY SURFACE FLOW...WILL ALLOW FOR A DECENT WARMING TREND INTO THE WEEKEND...BEFORE COLDER AIR BEGINS TO RETURN TO THE AREA NEXT WEEK. A FAIRLY PROGRESSIVE UPPER LEVEL PATTERN OVER THE CONUS WILL ALLOW THE COLDER AIRMASS...AND THE NORTHWESTERLY UPPER LEVEL FLOW DURING THE SHORT TERM PERIOD TO SHIFT OUT OF THE AREA BY LATE WEEK. AN INCREASE IN WEST-SOUTHWESTERLY LOW LEVEL FLOW...IN ASSOCIATION WITH HIGH PRESSURE OVER THE SOUTHERN CONUS...AND A COUPLE OF CLIPPER SYSTEMS OVER THE UPPER GREAT LAKES AND SOUTHERN CANADA...WILL HELP TRANSPORT WARMER TEMPERATURES OVER THE REGION FOR THE WEEKEND. OVERALL...IT APPEARS THAT MOST OF THE AREA COULD BE IN THE 40S...ESPECIALLY BY SUNDAY...WITH UPPER 40S TO NEAR 50 POSSIBLE SOUTH. OVERALL...PRECIPITATION CHANCES LOOK MEAGER OVER THE AREA...UNTIL POSSIBLY EARLY NEXT WEEK. DURING THIS PERIOD...MODEL AND ENSEMBLE GUIDANCE ARE IN GOOD AGREEMENT THAT A HIGH LATITUDE RIDGE WILL DEVELOP OVER THE WEST COAST...POSSIBLE EXTENDING UP INTO THE ARCTIC OCEAN. THIS PATTERN WOULD FAVOR A SIGNIFICANT TROUGH AND A MUCH COLDER ARCTIC AIRMASS TO SPILL SOUTHWARD OVER MUCH OF THE CENTRAL CONUS NEXT WEEK. CURRENTLY IT APPEARS THE COLDEST AIRMASS MIGHT NOT ARRIVE UNTIL TUESDAY OR WEDNESDAY OF NEXT WEEK...WHICH IS BEYOND THE CURRENT FORECAST PERIOD. HOWEVER...AS THIS COLD AIR BEGINS TO FILTER INTO THE AREA EARLY NEXT WEEK...A PERIOD OF SNOW SHOWERS WILL BE POSSIBLE. KJB && .AVIATION...FOR THE 06Z TAFS... 1130 PM CST STRATUS AND VSBY ARE FINALLY IMPROVING WITH ALL TAF SITES AT MVFR OR BETTER. EXPECTING CONDITIONS TO CONTINUE TO IMPROVE ESPECIALLY AS EAST WINDS INCREASE OVERNIGHT. GUSTY EAST WINDS DEVELOP BY THE EARLY MORNING HOURS AND MAX GUSTS AROUND 30 KT ARE EXPECTED THROUGH THE LATE MORNING AND AFTERNOON. PUSHED BACK THE TIMING OF PRECIP AS GUIDANCE CONTINUES TO SLOW THE SYSTEM/S PROGRESSION. RFD MAY SEE A BRIEF PERIOD OF SNOW EARLY THIS MORNING. EXPECTING RAIN TO SPREAD ACROSS THE TERMINALS IN THE LATE MORNING WITH MVFR CIGS. RAIN INTENSITY WILL INCREASE IN THE EARLY AFTN RESULTING IN IFR VSBYS. EMBEDDED THUNDER IS ALSO EXPECTED IN THE AFTERNOON WITH 1SM VSBY PSBL WITH THE STORMS. SOME STORMS COULD BE SEVERE. GUIDANCE THEN INDICATES THAT IFR TO LIFR CIGS WILL ARRIVE IN THE MID AFTN. WE ENTER THE DRY SECTOR OF THE SYSTEM THIS EVENING WITH SHOWERS ENDING AND WINDS BECOMING SOUTH. CIGS SHOULD BECOME VFR. WINDS BECOME WEST BEHIND THE COLD FRONT AND GUST TO 30 KT. SOME GUIDANCE MEMBERS FEATURE IFR CIGS...BUT ONLY HAVE MEDIUM-LOW CONFIDENCE IN THEM SO WENT WITH A SCT IFR GROUP FOR NOW. HAVE HIGH CONFIDENCE IN PRECIP TRENDS AND GUSTY EAST WINDS...MEDIUM- HIGH CONFIDENCE IN PRECIP TIMING...MEDIUM CONFIDENCE IN TSRA AND CIGS...LOW CONFIDENCE IN VSBY VALUES. JEE && .MARINE... 131 PM...LARGE WEAK HIGH PRESSURE EXTENDING FROM THE NORTHERN PLAINS TO THE SOUTHERN GREAT LAKES REGION WILL MOVE NORTHEAST INTO ONTARIO AND QUEBEC TUESDAY AS IT SLOWLY STRENGTHENS. LOW PRESSURE OVER COLORADO WILL MOVE NORTHEAST TUESDAY CROSSING CENTRAL LAKE MICHIGAN TUESDAY NIGHT INTO WEDNESDAY MORNING. THE GRADIENT IS EXPECTED TO TIGHTEN TUESDAY MORNING WITH EASTERLY GALES DEVELOPING OVER THE SOUTHERN PART OF THE LAKE TUESDAY MORNING AND THEN ACROSS THE NORTHERN PART OF THE LAKE TUESDAY AFTERNOON. THE CURRENT GALE WATCH TIMING LOOKS REASONABLE AND PLAN TO UPGRADE THE GALE WATCH TO A GALE WARNING THIS AFTERNOON. AS THE LOW LIFTS NORTHEAST INTO SOUTHWEST QUEBEC WEDNESDAY...COLD AIR ALONG WITH A TIGHT PRESSURE GRADIENT WILL ALLOW NORTHWESTERLY WINDS TO INCREASE TO 30 KTS WITH SOME POTENTIAL FOR LOW END GALES ESPECIALLY OVER NORTHERN PORTIONS OF THE LAKE. WINDS WILL DIMINISH THURSDAY AND REMAIN WESTERLY UNTIL ANOTHER LOW MOVES ACROSS ONTARIO FRIDAY NIGHT. WINDS WILL TURN MORE SOUTHWESTERLY AND INCREASE AHEAD OF THIS LOW FRIDAY NIGHT. CMS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022 UNTIL 2 AM TUESDAY. IN...NONE. LM...GALE WARNING...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...9 AM TUESDAY TO 6 PM TUESDAY. GALE WARNING...LMZ777-LMZ779...9 AM TUESDAY TO 9 PM TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1135 AM CST TUE FEB 2 2016 .AVIATION... 18Z TAFS CONTINUE TO SHOW GRADUAL CLEARING FROM THE WEST THIS AFTERNOON. MVFR CEILINGS LINGERING ALONG THE COAST WILL LIFT TO VFR LEVELS BY 21Z. VFR AREA WIDE OVERNIGHT AND ON THROUGH THE DAY TOMORROW. NW TO N WINDS DECREASING TO AROUND 5 KNOTS TONIGHT...THEN INCREASING TO 10 TO 15 KNOTS BEFORE SUNRISE AROUND CLL AND DURING THE MORNING FOR THE REST OF THE AREA. COULD SEE SOME GUSTS ON TUESDAY APPROACHING 20 KNOTS...ESPECIALLY TOWARD THE COASTAL AREA TAF SITES. 42 && .PREV DISCUSSION... /ISSUED 917 AM CST TUE FEB 2 2016/ UPDATE... A FEW LIGHT SHOWERS OR SPRINKLES MOVING THROUGH THE SARGENT TO PEARLAND TO LIBERTY AREA AND THIS AREA SHOULD SHIFT EASTWARD QUICKLY THIS MORNING AS THE INDIVIDUAL SHOWERS MOVE NORTHEAST. ACCUMULATIONS OF TRACE TO 0.05" POSSIBLE SO VERY LIGHT PRECIP. MIXING HAS LED TO SOME IMPROVEMENT IN FOG IN AROUND GALVESTON BAY AND THE NEARSHORE WATERS AND WITH THE FRONT FROM CLEVELAND TO PEARLAND TO ANGLETON THE FRONTAL PASSAGE SHOULD END ANY LINGERING FOG ACROSS GALVESTON BAY AND THE NEARSHORE WATERS SHORTLY. DRY WESTERLY WINDS THIS AFTERNOON WITH SKIES CLEARING QUICKLY SHOULD WARM IT UP QUICKLY TODAY AND HAVE NUDGED TEMPERATURES UP A FEW DEGREES. DRY AIR FILTERING INTO THE REGION FROM THE WEST AND WILL DO SO MORE AGGRESSIVELY THIS AFTERNOON. AMDAR SOUNDINGS AT AUSTIN AND HRRR/NAM MODEL SOUNDINGS HAVE PROMPTED A LOWERING OF DEWPOINTS AND TO BUMP UP TEMPERATURES FOR THE AREA TODAY. THIS WILL LIKELY DRIVE RH VALUES BELOW 20 PERCENT FOR A LARGE PART OF THE AREA. HAVE UPDATED FIRE WEATHER FORECASTS TO REFLECT THESE CHANGES. 45 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 71 40 56 34 56 / 10 0 0 0 0 HOUSTON (IAH) 76 41 61 36 58 / 20 0 0 0 0 GALVESTON (GLS) 68 51 60 43 57 / 20 0 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 3 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. SMALL CRAFT ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...45 AVIATION/MARINE...42
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
917 AM CST TUE FEB 2 2016 .UPDATE... A FEW LIGHT SHOWERS OR SPRINKLES MOVING THROUGH THE SARGENT TO PEARLAND TO LIBERTY AREA AND THIS AREA SHOULD SHIFT EASTWARD QUICKLY THIS MORNING AS THE INDIVIDUAL SHOWERS MOVE NORTHEAST. ACCUMULATIONS OF TRACE TO 0.05" POSSIBLE SO VERY LIGHT PRECIP. MIXING HAS LED TO SOME IMPROVEMENT IN FOG IN AROUND GALVESTON BAY AND THE NEARSHORE WATERS AND WITH THE FRONT FROM CLEVELAND TO PEARLAND TO ANGLETON THE FRONTAL PASSAGE SHOULD END ANY LINGERING FOG ACROSS GALVESTON BAY AND THE NEARSHORE WATERS SHORTLY. DRY WESTERLY WINDS THIS AFTERNOON WITH SKIES CLEARING QUICKLY SHOULD WARM IT UP QUICKLY TODAY AND HAVE NUDGED TEMPERATURES UP A FEW DEGREES. DRY AIR FILTERING INTO THE REGION FROM THE WEST AND WILL DO SO MORE AGGRESSIVELY THIS AFTERNOON. AMDAR SOUNDINGS AT AUSTIN AND HRRR/NAM MODEL SOUNDINGS HAVE PROMPTED A LOWERING OF DEWPOINTS AND TO BUMP UP TEMPERATURES FOR THE AREA TODAY. THIS WILL LIKELY DRIVE RH VALUES BELOW 20 PERCENT FOR A LARGE PART OF THE AREA. HAVE UPDATED FIRE WEATHER FORECASTS TO REFLECT THESE CHANGES. 45 && .DISCUSSION... && .PREV DISCUSSION... /ISSUED 523 AM CST TUE FEB 2 2016/ AVIATION... 12Z TAF DISCUSSION...SFC ANALYSIS HAS DRIER AIR JUST REACHING SE TX AND HAVE SEEN THE DEWPOINT AT KCLL DROP TO 35F ALREADY. EXPECT THIS BOUNDARY TO PUSH THROUGH THE AREA AND WINDS INCREASE FROM THE NW/W LATE THIS MORNING. ANY FOG WILL BE PATCHY AND SHORT LIVED. CIGS SHOULD REMAIN VFR OTHER THAN SOME BRIEF MVFR CIGS AHEAD OF THE FRONT. WINDS SHOULD DECOUPLE OVERNIGHT WITH A STRONG COLD FRONT PUSHING THROUGH THE AREA WED MORNING. THIS SHOULD INCREASE WINDS FROM THE NORTH AND CONTINUE TO SUPPORT VFR CIGS. 39 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 71 40 56 34 56 / 10 0 0 0 0 HOUSTON (IAH) 76 41 61 36 58 / 20 0 0 0 0 GALVESTON (GLS) 68 51 60 43 57 / 20 0 0 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...45