Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 12/31/11


AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1220 PM EST THU DEC 29 2011 .AVIATION... / 18Z TAFS / KIWX RADAR STILL INDICATING A FEW LIGHT SHOWERS/SPRINKLES MOVING TOWARD THE KFWA AREA...NOT ANTICIPATING ANY VSBY OR CEILING RESTRICTIONS WITH THIS SO WILL LEAVE OUT OF TAF TO BEGIN THE PERIOD. GUSTY SOUTHWEST WINDS THIS AFTERNOON OTHERWISE VFR CONDITIONS TO PREVAIL AT BOTH SITES UNTIL FRIDAY MORNING WHEN -RA WITH NEXT CLIPPER SYSTEM EXPECTED TO ARRIVE AND BRING WITH IT MVFR CIGS/VSBYS. && .PREV DISCUSSION... /ISSUED 355 AM EST THU DEC 29 2011/ SHORT TERM... / TODAY THROUGH FRIDAY NIGHT / 08Z SFC ANALYSIS SHOWS A SFC LOW NEAR MSP WITH A WARM FRONT EXTENDING SE INTO EASTERN IA AND WC IL. THE ASSOCIATED LOW AMPLITUDE SHORTWAVE OVER THE UPPER MIDWEST WILL SHEAR OUT TOWARDS THE CENTRAL GREAT LAKES TODAY ALLOWING THE WARM FRONT TO SURGE NEWD INTO THE SRN GREAT LAKES. RATHER MODEST OVERRUNNING/ISENTROPIC UPGLIDE EXPECTED JUST AHEAD OF THIS WARM FRONT THIS MORNING INTO EARLY THIS AFTERNOON (40 KNOTS OF CROSS ISOBARIC FLOW ON THE I290 SFC). UPSTREAM OBS/MOSAIC RADAR AND THE BULK OF 00Z GUIDANCE SUGGEST THAT NORTHERN AREAS MAY SEE A BRIEF PERIOD (AN HOUR OR TWO) OF VERY LIGHT PCPN THIS MORNING INTO EARLY THIS AFTN...WITH THE BETTER CHANCES FOR MEASURABLE PCPN (A COUPLE HUNDREDTHS AT BEST) BEING ACROSS THE NORTH/NORTHEAST WITH MAINLY VIRGA SOUTHWEST. LATEST RUC SOUNDINGS AND SFC OBS CONTINUE TO SUPPORT A POSSIBLE LIGHT MIX OF FREEZING DRIZZLE/SNOW TO START...LIKELY TRANSITIONING TO A BRIEF PERIOD OF DRIZZLE. ANY FREEZING DRIZZLE/RAIN BTW 12-15Z MAY CREATE A FEW SLICK SPOTS ON AREA ROADS...MAINLY NORTH OF ROUTE 6. OTHERWISE...EXPECT WINDS WILL PICK UP AND VEER BEHIND THE FRONTAL BOUNDARY WITH GUSTS OF 20-25 KNOTS POSSIBLE. A MUCH MORE VIGOROUS SHORTWAVE NOW ACROSS THE PAC NW WILL DIG INTO THE MID MS VALLEY AND NRN OH VALLEY BY LATER TONIGHT AND FRIDAY. GFS/ECMWF AGREE ON 120-140 METER 500 MB HEIGHT FALLS WITH THIS FEATURE SUPPORTING A RATHER HEALTHY LOW LVL RESPONSE AND THETA-E ADV INTO THE AREA WITH PCPN FOCUSING ALONG A DEEPENING BAROCLINIC ZONE. A MODEL CONSENSUS FAVORS THE NORTHERN HALF OF THE FA FOR BEST CHANCES FOR MEASURABLE RAINFALL. AMOUNTS ARE FCST TO RANGE BETWEEN 0.20" AND 0.50" HERE. HIRES GUIDANCE IS A LITTLE FARTHER SOUTH WITH THE TRACK OF THIS SYSTEM SO DID CONTINUE WITH CHC/SLIGHT WORDING FOR SNOW IN THE FAR NORTH...WITH AREAS JUST NORTH OF THE FA IN A GOOD POSITION FOR A MODERATE SNOWFALL. OTHERWISE...TEMPS ARE FCST TO BE ABOVE NORMAL THIS PERIOD WITH ONLY MINOR TWEAKS MADE. LONG TERM... OVERALL LARGE SCALE PATTERN STILL EXPECTED TO BECOME MORE AMPLIFIED THROUGH THE LONG TERM WITH BRIEF ARCTIC INTRUSION STILL EXPECTED LATTER HALF OF WEEKEND INTO NEXT WEEK. MEDIUM RANGE MODELS REMAIN IN GOOD AGREEMENT ON LARGE SCALE WITH DIFFERENCES CONTINUING IN THE DETAILS. CR ALLBLEND LOADED AND COLLABORATED SOME TWEAKS TO TEMPS AND POPS. A QUIET START EXPECTED ON SATURDAY WITH WARM AIR ADVECTION AHEAD OF FIRST COLD FRONT AND TEMPERATURES RISING WELL ABOVE NORMAL FOR LATE DECEMBER. SHOULD SEE 40S ACROSS ENTIRE AREA FOR HIGHS WITH 50S NOT OUT OF QUESTION SOUTH AND WEST. WARM AIR ADVECTION CONTINUES FIRST HALF OF SATURDAY NIGHT WITH TEMPS STEADY OR SLOWLY RISING UNTIL INITIAL FRONTAL PASSAGE LATE. HAVE TRIED TO DETAIL THIS SCENARIO IN HOURLY GRIDS WITH STEADY TEMPS THROUGH 06Z THEN A SLOW FALL TOWARD 12Z. DETAIL DIFFERENCES AND COMPLICATIONS IN FORECAST BEGIN IN THIS SATURDAY NIGHT INTO SUNDAY TIME FRAME WITH STRENGTH AND TIMING OF COLD AIR ADVECTION AND ANY ASSOCIATED PCPN. 850MB TEMPS BEGIN TO FALL AFTER 06Z SUNDAY WITH 1000-850MB THICKNESSES FOLLOWING. MODELS SHOWING LITTLE IN WAY OF PCPN WITH THIS FRONT GIVEN POSITIVELY TILTED UPPER SYSTEM AND NO STRONG MOISTURE SURGE AHEAD OF IT. DEEPENING SURFACE LOW REMAINS WELL NORTH OF AREA WITH ONLY SUBTLE INDICATIONS OF SECONDARY LOW DEVELOPMENT ALONG FRONT BY A FEW MODELS. HAVE THEREFORE ALLOWED LOW CHANCE POPS TO RIDE SAT NIGHT AND SUNDAY MORNING. SUNDAY BEGINNING TO LOOK DRY IN WAKE OF INITIAL COLD FRONT WITH SOME SUNSHINE EVEN POSSIBLE IN DRY SLOT BEFORE SECONDARY ARCTIC FRONT LATER IN THE DAY. IF THIS OCCURS...FALLING TEMPS EARLY IN THE MORNING MAY BECOME STEADY OR EVEN RISE A FEW DEGREES BEFORE SECONDARY FRONT BRINGS MUCH COLDER AIR IN DURING THE AFTERNOON. FOR NOW HAVE CHOSEN TO GO WITH SLOWLY FALLING TEMPS DURING THE DAY GIVEN TEMPS LOOK TO FALL IN THE AFTERNOON REGARDLESS. WITH ARCTIC INTRUSION SUNDAY NIGHT WILL SEE BEST LAKE EFFECT SNOW POTENTIAL OF THE SEASON AS DELTA T VALUES CLIMB WITH SURFACE TO 850MB WELL INTO LOWER 20S. SURFACE TO 700MB DELTA T VALUES REACH CRITICAL 30C THRESHOLD WHICH IS A GOOD INDICATOR OF HEAVY SNOW POTENTIAL. LIMITING FACTOR CONTINUES TO BE MOISTURE PROFILES BUT MEDIUM RANGE MODELS ARE SHOWING SOME DECENT SYNOPTIC MOISTURE LATE SUNDAY NIGHT THROUGH MONDAY WHICH WOULD SUPPORT A PERIOD OF HEAVY LAKE EFFECT SNOW BANDS. NORTHWEST FLOW AND WIND FIELD SUGGEST MULTI-BANDED EVENT WHICH MAKES PINNING DOWN AMOUNTS AND LOCATIONS DIFFICULT AT THIS TIME PROJECTION. HAVE BUMPED NW FETCH FAVORED AREAS INTO LIKELY CATEGORY FOR NOW. HEADLINES POSSIBLE LATER THIS WEEKEND INTO EARLY NEXT WEEK AS MOISTURE PROFILES BECOME BETTER DEFINED BY HIGHER RESOLUTION MODELS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...STEINWEDEL LONG TERM...LASHLEY AVIATION...LOGSDON
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
554 AM EST THU DEC 29 2011 .AVIATION... / 12Z TAFS / WARM FRONT ASSOCIATED WITH AN APPROACHING SHORTWAVE TROUGH ACROSS THE UPPER MIDWEST WILL MIX NEWD THROUGH THE FA TODAY ALLOWING WINDS TO VEER AND BECOME SOMEWHAT GUSTY BY LATE MORNING/AFTN. A NARROW BROKEN BAND OF LIGHT MIXED PRECIPITATION ACROSS NRN IL AND SRN WI MAY BRING A BRIEF PERIOD OF MAINLY LIQUID PRECIP TO THE TERMINALS THIS MORNING. SFC TEMPS SHOULD BE BETWEEN 30 AND 32 AT SBN WHEN THIS MOVES THROUGH SO CONTINUED WITH A 12-14Z TEMPO GROUP FOR -FZRA HERE. THIS ACTIVITY MAY IMPACT FWA LATER THIS MORNING WITH TEMPS LIKELY JUST ABOVE FREEZING BY THEN. KEPT VIS/CIGS VFR WITH THE FRONTAL PASSAGE...ALTHOUGH CANNOT RULE OUT A TIME OF MVFR CONDITIONS DURING THIS TIME...ESPECIALLY BTW 15-20Z. OTHERWISE DRY/VFR LATER THIS AFTN AND EVENING WITH DETERIORATING FLIGHT CONDITIONS POSSIBLE TOWARDS DAYBREAK THURSDAY AS THE NEXT SHORTWAVE AND CHANCE FOR RAIN MOVES IN. && .PREV DISCUSSION... /ISSUED 355 AM EST THU DEC 29 2011/ SHORT TERM... / TODAY THROUGH FRIDAY NIGHT / 08Z SFC ANALYSIS SHOWS A SFC LOW NEAR MSP WITH A WARM FRONT EXTENDING SE INTO EASTERN IA AND WC IL. THE ASSOCIATED LOW AMPLITUDE SHORTWAVE OVER THE UPPER MIDWEST WILL SHEAR OUT TOWARDS THE CENTRAL GREAT LAKES TODAY ALLOWING THE WARM FRONT TO SURGE NEWD INTO THE SRN GREAT LAKES. RATHER MODEST OVERRUNNING/ISENTROPIC UPGLIDE EXPECTED JUST AHEAD OF THIS WARM FRONT THIS MORNING INTO EARLY THIS AFTERNOON (40 KNOTS OF CROSS ISOBARIC FLOW ON THE I290 SFC). UPSTREAM OBS/MOSAIC RADAR AND THE BULK OF 00Z GUIDANCE SUGGEST THAT NORTHERN AREAS MAY SEE A BRIEF PERIOD (AN HOUR OR TWO) OF VERY LIGHT PCPN THIS MORNING INTO EARLY THIS AFTN...WITH THE BETTER CHANCES FOR MEASURABLE PCPN (A COUPLE HUNDREDTHS AT BEST) BEING ACROSS THE NORTH/NORTHEAST WITH MAINLY VIRGA SOUTHWEST. LATEST RUC SOUNDINGS AND SFC OBS CONTINUE TO SUPPORT A POSSIBLE LIGHT MIX OF FREEZING DRIZZLE/SNOW TO START...LIKELY TRANSITIONING TO A BRIEF PERIOD OF DRIZZLE. ANY FREEZING DRIZZLE/RAIN BTW 12-15Z MAY CREATE A FEW SLICK SPOTS ON AREA ROADS...MAINLY NORTH OF ROUTE 6. OTHERWISE...EXPECT WINDS WILL PICK UP AND VEER BEHIND THE FRONTAL BOUNDARY WITH GUSTS OF 20-25 KNOTS POSSIBLE. A MUCH MORE VIGOROUS SHORTWAVE NOW ACROSS THE PAC NW WILL DIG INTO THE MID MS VALLEY AND NRN OH VALLEY BY LATER TONIGHT AND FRIDAY. GFS/ECMWF AGREE ON 120-140 METER 500 MB HEIGHT FALLS WITH THIS FEATURE SUPPORTING A RATHER HEALTHY LOW LVL RESPONSE AND THETA-E ADV INTO THE AREA WITH PCPN FOCUSING ALONG A DEEPENING BAROCLINIC ZONE. A MODEL CONSENSUS FAVORS THE NORTHERN HALF OF THE FA FOR BEST CHANCES FOR MEASURABLE RAINFALL. AMOUNTS ARE FCST TO RANGE BETWEEN 0.20" AND 0.50" HERE. HIRES GUIDANCE IS A LITTLE FARTHER SOUTH WITH THE TRACK OF THIS SYSTEM SO DID CONTINUE WITH CHC/SLIGHT WORDING FOR SNOW IN THE FAR NORTH...WITH AREAS JUST NORTH OF THE FA IN A GOOD POSITION FOR A MODERATE SNOWFALL. OTHERWISE...TEMPS ARE FCST TO BE ABOVE NORMAL THIS PERIOD WITH ONLY MINOR TWEAKS MADE. LONG TERM... OVERALL LARGE SCALE PATTERN STILL EXPECTED TO BECOME MORE AMPLIFIED THROUGH THE LONG TERM WITH BRIEF ARCTIC INTRUSION STILL EXPECTED LATTER HALF OF WEEKEND INTO NEXT WEEK. MEDIUM RANGE MODELS REMAIN IN GOOD AGREEMENT ON LARGE SCALE WITH DIFFERENCES CONTINUING IN THE DETAILS. CR ALLBLEND LOADED AND COLLABORATED SOME TWEAKS TO TEMPS AND POPS. A QUIET START EXPECTED ON SATURDAY WITH WARM AIR ADVECTION AHEAD OF FIRST COLD FRONT AND TEMPERATURES RISING WELL ABOVE NORMAL FOR LATE DECEMBER. SHOULD SEE 40S ACROSS ENTIRE AREA FOR HIGHS WITH 50S NOT OUT OF QUESTION SOUTH AND WEST. WARM AIR ADVECTION CONTINUES FIRST HALF OF SATURDAY NIGHT WITH TEMPS STEADY OR SLOWLY RISING UNTIL INITIAL FRONTAL PASSAGE LATE. HAVE TRIED TO DETAIL THIS SCENARIO IN HOURLY GRIDS WITH STEADY TEMPS THROUGH 06Z THEN A SLOW FALL TOWARD 12Z. DETAIL DIFFERENCES AND COMPLICATIONS IN FORECAST BEGIN IN THIS SATURDAY NIGHT INTO SUNDAY TIME FRAME WITH STRENGTH AND TIMING OF COLD AIR ADVECTION AND ANY ASSOCIATED PCPN. 850MB TEMPS BEGIN TO FALL AFTER 06Z SUNDAY WITH 1000-850MB THICKNESSES FOLLOWING. MODELS SHOWING LITTLE IN WAY OF PCPN WITH THIS FRONT GIVEN POSITIVELY TILTED UPPER SYSTEM AND NO STRONG MOISTURE SURGE AHEAD OF IT. DEEPENING SURFACE LOW REMAINS WELL NORTH OF AREA WITH ONLY SUBTLE INDICATIONS OF SECONDARY LOW DEVELOPMENT ALONG FRONT BY A FEW MODELS. HAVE THEREFORE ALLOWED LOW CHANCE POPS TO RIDE SAT NIGHT AND SUNDAY MORNING. SUNDAY BEGINNING TO LOOK DRY IN WAKE OF INITIAL COLD FRONT WITH SOME SUNSHINE EVEN POSSIBLE IN DRY SLOT BEFORE SECONDARY ARCTIC FRONT LATER IN THE DAY. IF THIS OCCURS...FALLING TEMPS EARLY IN THE MORNING MAY BECOME STEADY OR EVEN RISE A FEW DEGREES BEFORE SECONDARY FRONT BRINGS MUCH COLDER AIR IN DURING THE AFTERNOON. FOR NOW HAVE CHOSEN TO GO WITH SLOWLY FALLING TEMPS DURING THE DAY GIVEN TEMPS LOOK TO FALL IN THE AFTERNOON REGARDLESS. WITH ARCTIC INTRUSION SUNDAY NIGHT WILL SEE BEST LAKE EFFECT SNOW POTENTIAL OF THE SEASON AS DELTA T VALUES CLIMB WITH SURFACE TO 850MB WELL INTO LOWER 20S. SURFACE TO 700MB DELTA T VALUES REACH CRITICAL 30C THRESHOLD WHICH IS A GOOD INDICATOR OF HEAVY SNOW POTENTIAL. LIMITING FACTOR CONTINUES TO BE MOISTURE PROFILES BUT MEDIUM RANGE MODELS ARE SHOWING SOME DECENT SYNOPTIC MOISTURE LATE SUNDAY NIGHT THROUGH MONDAY WHICH WOULD SUPPORT A PERIOD OF HEAVY LAKE EFFECT SNOW BANDS. NORTHWEST FLOW AND WIND FIELD SUGGEST MULTI-BANDED EVENT WHICH MAKES PINNING DOWN AMOUNTS AND LOCATIONS DIFFICULT AT THIS TIME PROJECTION. HAVE BUMPED NW FETCH FAVORED AREAS INTO LIKELY CATEGORY FOR NOW. HEADLINES POSSIBLE LATER THIS WEEKEND INTO EARLY NEXT WEEK AS MOISTURE PROFILES BECOME BETTER DEFINED BY HIGHER RESOLUTION MODELS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR LMZ043. SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR LMZ046. && $$ SHORT TERM...STEINWEDEL LONG TERM...LASHLEY AVIATION...STEINWEDEL
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
355 AM EST THU DEC 29 2011 .SHORT TERM... / TODAY THROUGH FRIDAY NIGHT / 08Z SFC ANALYSIS SHOWS A SFC LOW NEAR MSP WITH A WARM FRONT EXTENDING SE INTO EASTERN IA AND WC IL. THE ASSOCIATED LOW AMPLITUDE SHORTWAVE OVER THE UPPER MIDWEST WILL SHEAR OUT TOWARDS THE CENTRAL GREAT LAKES TODAY ALLOWING THE WARM FRONT TO SURGE NEWD INTO THE SRN GREAT LAKES. RATHER MODEST OVERRUNNING/ISENTROPIC UPGLIDE EXPECTED JUST AHEAD OF THIS WARM FRONT THIS MORNING INTO EARLY THIS AFTERNOON (40 KNOTS OF CROSS ISOBARIC FLOW ON THE I290 SFC). UPSTREAM OBS/MOSAIC RADAR AND THE BULK OF 00Z GUIDANCE SUGGEST THAT NORTHERN AREAS MAY SEE A BRIEF PERIOD (AN HOUR OR TWO) OF VERY LIGHT PCPN THIS MORNING INTO EARLY THIS AFTN...WITH THE BETTER CHANCES FOR MEASURABLE PCPN (A COUPLE HUNDREDTHS AT BEST) BEING ACROSS THE NORTH/NORTHEAST WITH MAINLY VIRGA SOUTHWEST. LATEST RUC SOUNDINGS AND SFC OBS CONTINUE TO SUPPORT A POSSIBLE LIGHT MIX OF FREEZING DRIZZLE/SNOW TO START...LIKELY TRANSITIONING TO A BRIEF PERIOD OF DRIZZLE. ANY FREEZING DRIZZLE/RAIN BTW 12-15Z MAY CREATE A FEW SLICK SPOTS ON AREA ROADS...MAINLY NORTH OF ROUTE 6. OTHERWISE...EXPECT WINDS WILL PICK UP AND VEER BEHIND THE FRONTAL BOUNDARY WITH GUSTS OF 20-25 KNOTS POSSIBLE. A MUCH MORE VIGOROUS SHORTWAVE NOW ACROSS THE PAC NW WILL DIG INTO THE MID MS VALLEY AND NRN OH VALLEY BY LATER TONIGHT AND FRIDAY. GFS/ECMWF AGREE ON 120-140 METER 500 MB HEIGHT FALLS WITH THIS FEATURE SUPPORTING A RATHER HEALTHY LOW LVL RESPONSE AND THETA-E ADV INTO THE AREA WITH PCPN FOCUSING ALONG A DEEPENING BAROCLINIC ZONE. A MODEL CONSENSUS FAVORS THE NORTHERN HALF OF THE FA FOR BEST CHANCES FOR MEASURABLE RAINFALL. AMOUNTS ARE FCST TO RANGE BETWEEN 0.20" AND 0.50" HERE. HIRES GUIDANCE IS A LITTLE FARTHER SOUTH WITH THE TRACK OF THIS SYSTEM SO DID CONTINUE WITH CHC/SLIGHT WORDING FOR SNOW IN THE FAR NORTH...WITH AREAS JUST NORTH OF THE FA IN A GOOD POSITION FOR A MODERATE SNOWFALL. OTHERWISE...TEMPS ARE FCST TO BE ABOVE NORMAL THIS PERIOD WITH ONLY MINOR TWEAKS MADE. && .LONG TERM... OVERALL LARGE SCALE PATTERN STILL EXPECTED TO BECOME MORE AMPLIFIED THROUGH THE LONG TERM WITH BRIEF ARCTIC INTRUSION STILL EXPECTED LATTER HALF OF WEEKEND INTO NEXT WEEK. MEDIUM RANGE MODELS REMAIN IN GOOD AGREEMENT ON LARGE SCALE WITH DIFFERENCES CONTINUING IN THE DETAILS. CR ALLBLEND LOADED AND COLLABORATED SOME TWEAKS TO TEMPS AND POPS. A QUIET START EXPECTED ON SATURDAY WITH WARM AIR ADVECTION AHEAD OF FIRST COLD FRONT AND TEMPERATURES RISING WELL ABOVE NORMAL FOR LATE DECEMBER. SHOULD SEE 40S ACROSS ENTIRE AREA FOR HIGHS WITH 50S NOT OUT OF QUESTION SOUTH AND WEST. WARM AIR ADVECTION CONTINUES FIRST HALF OF SATURDAY NIGHT WITH TEMPS STEADY OR SLOWLY RISING UNTIL INITIAL FRONTAL PASSAGE LATE. HAVE TRIED TO DETAIL THIS SCENARIO IN HOURLY GRIDS WITH STEADY TEMPS THROUGH 06Z THEN A SLOW FALL TOWARD 12Z. DETAIL DIFFERENCES AND COMPLICATIONS IN FORECAST BEGIN IN THIS SATURDAY NIGHT INTO SUNDAY TIME FRAME WITH STRENGTH AND TIMING OF COLD AIR ADVECTION AND ANY ASSOCIATED PCPN. 850MB TEMPS BEGIN TO FALL AFTER 06Z SUNDAY WITH 1000-850MB THICKNESSES FOLLOWING. MODELS SHOWING LITTLE IN WAY OF PCPN WITH THIS FRONT GIVEN POSITIVELY TILTED UPPER SYSTEM AND NO STRONG MOISTURE SURGE AHEAD OF IT. DEEPENING SURFACE LOW REMAINS WELL NORTH OF AREA WITH ONLY SUBTLE INDICATIONS OF SECONDARY LOW DEVELOPMENT ALONG FRONT BY A FEW MODELS. HAVE THEREFORE ALLOWED LOW CHANCE POPS TO RIDE SAT NIGHT AND SUNDAY MORNING. SUNDAY BEGINNING TO LOOK DRY IN WAKE OF INITIAL COLD FRONT WITH SOME SUNSHINE EVEN POSSIBLE IN DRY SLOT BEFORE SECONDARY ARCTIC FRONT LATER IN THE DAY. IF THIS OCCURS...FALLING TEMPS EARLY IN THE MORNING MAY BECOME STEADY OR EVEN RISE A FEW DEGREES BEFORE SECONDARY FRONT BRINGS MUCH COLDER AIR IN DURING THE AFTERNOON. FOR NOW HAVE CHOSEN TO GO WITH SLOWLY FALLING TEMPS DURING THE DAY GIVEN TEMPS LOOK TO FALL IN THE AFTERNOON REGARDLESS. WITH ARCTIC INTRUSION SUNDAY NIGHT WILL SEE BEST LAKE EFFECT SNOW POTENTIAL OF THE SEASON AS DELTA T VALUES CLIMB WITH SURFACE TO 850MB WELL INTO LOWER 20S. SURFACE TO 700MB DELTA T VALUES REACH CRITICAL 30C THRESHOLD WHICH IS A GOOD INDICATOR OF HEAVY SNOW POTENTIAL. LIMITING FACTOR CONTINUES TO BE MOISTURE PROFILES BUT MEDIUM RANGE MODELS ARE SHOWING SOME DECENT SYNOPTIC MOISTURE LATE SUNDAY NIGHT THROUGH MONDAY WHICH WOULD SUPPORT A PERIOD OF HEAVY LAKE EFFECT SNOW BANDS. NORTHWEST FLOW AND WIND FIELD SUGGEST MULTI-BANDED EVENT WHICH MAKES PINNING DOWN AMOUNTS AND LOCATIONS DIFFICULT AT THIS TIME PROJECTION. HAVE BUMPED NW FETCH FAVORED AREAS INTO LIKELY CATEGORY FOR NOW. HEADLINES POSSIBLE LATER THIS WEEKEND INTO EARLY NEXT WEEK AS MOISTURE PROFILES BECOME BETTER DEFINED BY HIGHER RESOLUTION MODELS. && .AVIATION... / 06Z TAFS / WARM FRONT ASSOCIATED WITH AN APPROACHING SHORTWAVE TROUGH ACROSS THE UPPER MIDWEST WILL MIX NEWD THROUGH THE FA THIS MORNING ALLOWING WINDS TO VEER AND GUSTY BY LATE MORNING/AFTN. UPPER MIDWEST RADAR MOSAIC AND SFC OBS SHOW A NARROW BAND OF LIGHT RAIN IN AREA OF STRONG ISENTROPIC UPGLIDE ALONG WARM FRONT. EXPECT THIS FORCING AND SATURATION TO PROPAGATE THROUGH THE LOCAL AREA LATER THIS MORNING. 00Z MODEL SOUNDINGS CONTINUE TO SUPPORT PCPN MAINLY IN THE LIQUID FORM...WITH A PERIOD OF -FZRA/FZDZ POSSIBLE AT SBN BEFORE SFC TEMPS WARM ABOVE FREEZING BY 14/15Z. LESSER CHANCES OF PCPN AT FWA SO CONTINUED WITH PROB30 MENTION HERE. ALSO OPTED FOR -RA/DZ WORDING IN PROB30 INSTEAD OF FZDZ AS SFC TEMPS LOOK TO WARM JUST ABOVE FREEZING BY THE TIME FORCING/TOP DOWN SATURATION WORKS IN. OTHERWISE...CIGS WILL LIKELY LOWER TO MVFR FOR A TIME ALONG THE AFOREMENTIONED FRONTAL BOUNDARY WITH IMPROVED MIXING IN ITS WAKE SUPPORTING VFR CIGS BY THIS AFTN/EVE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 11 PM EST THIS EVENING FOR LMZ043. SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 5 PM EST THIS AFTERNOON FOR LMZ046. && $$ SHORT TERM...STEINWEDEL LONG TERM...LASHLEY AVIATION...STEINWEDEL
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1222 AM EST THU DEC 29 2011 .AVIATION... / 06Z TAFS / WARM FRONT ASSOCIATED WITH AN APPROACHING SHORTWAVE TROUGH ACROSS THE UPPER MIDWEST WILL MIX NEWD THROUGH THE FA THIS MORNING ALLOWING WINDS TO VEER AND GUSTY BY LATE MORNING/AFTN. UPPER MIDWEST RADAR MOSAIC AND SFC OBS SHOW A NARROW BAND OF LIGHT RAIN IN AREA OF STRONG ISENTROPIC UPGLIDE ALONG WARM FRONT. EXPECT THIS FORCING AND SATURATION TO PROPAGATE THROUGH THE LOCAL AREA LATER THIS MORNING. 00Z MODEL SOUNDINGS CONTINUE TO SUPPORT PCPN MAINLY IN THE LIQUID FORM...WITH A PERIOD OF -FZRA/FZDZ POSSIBLE AT SBN BEFORE SFC TEMPS WARM ABOVE FREEZING BY 14/15Z. LESSER CHANCES OF PCPN AT FWA SO CONTINUED WITH PROB30 MENTION HERE. ALSO OPTED FOR -RA/DZ WORDING IN PROB30 INSTEAD OF FZDZ AS SFC TEMPS LOOK TO WARM JUST ABOVE FREEZING BY THE TIME FORCING/TOP DOWN SATURATION WORKS IN. OTHERWISE...CIGS WILL LIKELY LOWER TO MVFR FOR A TIME ALONG THE AFOREMENTIONED FRONTAL BOUNDARY WITH IMPROVED MIXING IN ITS WAKE SUPPORTING VFR CIGS BY THIS AFTN/EVE. && .PREV DISCUSSION... /ISSUED 730 PM EST WED DEC 28 2011/ UPDATE... NEXT CLIPPER SYSTEM LOOKS TO IMPACT THE AREA VERY LATE TONIGHT INTO THURSDAY MORNING. STRENGTHENING WESTERLY LOW LEVEL FLOW LATER TONIGHT IN ADVANCE OF THIS FEATURE WILL BEGIN TO ADVECT WARMER LOW LEVEL AIR EASTWARD. POSITIVE LOW LEVEL THEATE ADVECTION ALREADY UNDERWAY ACROSS THE LOCAL AREA EARLY THIS EVENING...ALTHOUGH AIR MASS INITIALLY OVER THE AREA IS QUITE DRY AND MOISTURE AVAILABILITY REMAINS THE PRIMARY LIMITING FACTOR TO PRECIPITATION AMOUNTS WITH THIS CLIPPER. ONLY CHANGE THAT WILL BE MADE TO PREVIOUS FORECAST WILL BE TO ADD SLIGHT CHANCE MENTION OF LIGHT FREEZING RAIN IN THE 11Z TO 15Z TIMEFRAME. DESPITE WARM ADVECTION OVERNIGHT...SHOULD MAINTAIN ENOUGH OF A SHALLOW COLD LAYER TO PROVIDE A BRIEF WINDOW OF SOME LIGHT FREEZING PRECIPITATION. LINGERING SNOWCOVER ACROSS PORTIONS OF THE AREA MAY ALSO AID IN KEEPING LOW LEVEL TEMPS AT OR BELOW FREEZING FOR A LONGER DURATION EARLY THURSDAY MORNING. SOME LOWER CONFIDENCE STILL EXISTS HOWEVER...WITH SOME CONCERNS THAT MOISTURE AVAILABILITY CONCERNS COULD BE MANIFESTED IN PROFILES TOO DRY FOR PRECIP WHILE A THERMODYANAMIC PROFILE SUPPORTIVE OF FREEZING RAIN EXISTS. GIVEN THIS LOWER CONFIDENCE AND EXPECTED LIGHT PRECIP AMOUNTS WILL NOT BE ISSUING ANY HEADLINES BUT WILL LIKELY ISSUE AN SPS ADDRESSING THE CHANCE OF A BRIEF PERIOD OF LIGHT FREEZING RAIN DURING THIS PERIOD. NAM/RUC ISENTROPIC ANALYSES STILL GENERALLY SUPPORTIVE OF PREVIOUS FORECAST IN AREAS OF HIGHEST CHANCE POPS ACROSS THE NORTHERN THIRD OF THE AREA...AND ALSO EXTENDING ACROSS MUCH OF NORTHWEST OHIO THURSDAY MORNING. UPDATED FORECAST WILL BE SENT OVER THE NEXT HOUR TO ADD THIS SLIGHT CHANCE LIGHT FREEZING RAIN MENTION. PREV DISCUSSION... /ISSUED 425 PM EST WED DEC 28 2011/ SHORT TERM... TONIGHT THROUGH THURSDAY NIGHT PAIR OF WEAK CLIPPER SYSTEMS TO IMPACT THE AREA IN THE SHORT TERM. WATER VAPOR IMAGERY AND LATEST RUC ANALYSIS DEPICTING LEAD SHORT WAVE OVER SOUTHERN MANITOBA AND MOVING INTO WESTERN ONTARIO. THIS FEATURE EXPECTED TO WEAKEN/SHEAR OUT IN FAST MOVING NW FLOW PATTERN AS IT DROPS DOWN INTO THE NORTHERN GREAT LAKES TONIGHT/THU AM. RESULT SHOULD BE BETTER CHANCES FOR PRECIP TO REMAIN NORTH OF THE AREA WHERE BETTER FORCING AND MOISTURE WILL BE PRESENT...BUT CLOSE ENOUGH TO MAINTAIN SMALL CHANCE POPS FOR NORTHERN TWO THIRDS OF CWA. MODELS INDICATING DECENT SFC/LOW LEVEL RESPONSE WITH THIS FIRST SHORT WAVE RESULTING IN GOOD WAA IN ADVANCE OF THIS SYSTEM WHICH WILL HAVE TEMPS SLOWLY RISING AFTER MIDNIGHT TONIGHT AND ALSO BRING PRECIP TYPE INTO QUESTION. FCST SOUNDINGS SHOWING DECENT ELEVATED WARM LAYER AND MORE FAVORABLE PROFILES IN SUPPORT OF LIQUID PRECIP...AND WHILE 12Z SOUNDINGS FROM KOAX AND KSGF LEND CREDENCE TO THIS SCENARIO...STILL NOT CONVINCED THAT MUCH LOW LEVEL WARMING WILL BE REALIZED WITH FAST MOVING SYSTEM SO WILL KEEP WITH RA/SN MIX IN WX GRIDS ATTM. 140KT JET COMING ONSHORE IN PACIFIC NW THIS MORNING WILL DRIVE SECOND SHORT WAVE INTO THE AREA QUICKLY BEHIND THE FIRST THURSDAY NIGHT. THIS WAVE WILL DIG FURTHER SOUTH AND BRING BETTER FORCING AND MOISTURE INTO THE FORECAST AREA...AS CURRENTLY REFLECTED IN GRIDS WITH LOW TO HIGH CHANCE POPS FROM EAST TO WEST ACROSS THE CWA. STILL LIKE THE NOTION OF A SMALL WINDOW OF DRY WX BETWEEN THESE TWO SYSTEMS SO WILL STAY WITH DRY FCST 00-06Z FRI. WITH RELATIVELY WARMER AIR IN PLACE...WILL TREND WX GRIDS TOWARD LIQUID PRECIP WITH ALL RAIN IN THE SOUTHERN TIER BUT STAY WITH MIX ELSEWHERE GIVEN NOCTURNAL TIMING. ABOVE NORMAL TEMPS THROUGH THE PERIOD AND GUIDANCE REASONABLE IN HANDLING THIS. LONG TERM... FRIDAY THROUGH WEDNESDAY AN UPPER LEVEL DISTURBANCE WILL TRACK SOUTHEASTWARD FROM SOUTHERN ALBERTA/SASKATCHEWAN THURSDAY MORNING INTO THE MIDWEST BY FRIDAY MORNING. MEDIUM RANGE MODELS ARE IN DECENT AGREEMENT WITH THE TRACK OF THE WAVE AND THE ATTENDANT SURFACE LOW...HOWEVER MINOR TIMING DIFFERENCES EXIST. WENT AHEAD AND BUMPED POPS UP TO LIKELY ACROSS THE NORTHERN HALF OF THE CWA FRIDAY MORNING...ALONG THE PREFERRED TRACK OF THE SURFACE LOW. PRECIPITATION TYPE CONCERNS REMAIN AN ISSUE WITH THIS SYSTEM. THERMAL PROFILES PER MODELS SOUNDINGS SUGGEST MOSTLY RAIN WITH THIS SYSTEM THROUGH THE DAY FRIDAY...WITH COLDER AIR ARRIVING LATE AFTERNOON...INTRODUCING A MIX AND EVENTUAL CHANGEOVER TO SNOW AND PRECIPITATION TAPERS OFF. HOWEVER...GIVEN THE TIMING DIFFERENCES BETWEEN MODELS....AND SLIGHT MODEL DIFFERENCES WITH THE TRACK OF THE SYSTEM...PREFERRED TO LEAVE A RAIN/SNOW MENTION FOR FRIDAY ACROSS THE NORTH AND FRIDAY NIGHT EVERYWHERE. WILL DEFER REFINING OF P-TYPE TO NEXT FORECAST CYCLE AND HOPEFULLY MORE CONSISTENT MODEL SOLUTIONS. NO MAJOR CHANGES TO TEMPERATURES FRIDAY AND FRIDAY NIGHT. SYSTEM EXITS THE REGION BY SATURDAY MORNING...AND HIGH PRESSURE BUILDS INTO THE REGION FROM THE SOUTHWEST. CONDITIONS WILL BE DRY THROUGH THE DAY SATURDAY...BEFORE A SIGNIFICANT PATTERN CHANGE ARRIVES ACROSS THE REGION. UPPER LEVEL TROF WILL DIG SOUTHEAST FROM CANADA INTO THE EASTERN CONUS SUNDAY INTO EARLY NEXT WEEK...AND ALONG WITH IT A POLAR AIR MASS...WITH MODEL H85 TEMPS APPROACHING -20C BY TUESDAY ACROSS THE REGION. SFC LOW PRESSURE WILL MOVE ACROSS THE NORTHERN TIER INTO THE GREAT LAKES REGION BY BY SUNDAY. MODELS DIFFER WITH THE EXACT TRACK OF THE LOW...WITH THE GFS SUPPORTING A FASTER MORE SOUTHERLY TRACK...AND THE ECMWF A BIT SLOWER WITH A MORE NORTHERLY TRACK. CONSEQUENTLY...THE GFS SUPPORTS STRONGER FORCING ACROSS THE REGION SATURDAY NIGHT INTO SUNDAY...WHILE THE ECMWF SUPPORTS WEAKER FORCING MOVING INTO THE AREA DURING THE DAY SUNDAY. ALLBLEND PROCEDURE INTRODUCED SLIGHT CHANCE POPS ON SATURDAY NIGHT...WHICH HAVE BEEN RETAINED FOR COLLABORATIVE PURPOSES. FEEL THAT THE GFS IS SLIGHTLY TO FAST WITH THE TRACK OF THE SYSTEM AND BEST PRECIP CHANCES WILL BE DURING THE DAY SUNDAY. COLD AIR WILL THEN FILTER INTO THE REGION BEHIND THE FRONT...WHICH WILL BE THE CATALYST FOR LAKE EFFECT SNOW LATE SUNDAY THROUGH TUESDAY ACROSS THE AREA. MODELS ARE IN DECENT AGREEMENT OF A NW TO NORTHERLY FETCH AND ADEQUATE MOISTURE PROFILE...WITH LAKE SFC TO H85 DELTA TS IN EXCESS OF 20C...AND LAKE SFC TO H7 DELTA TS IN THE MID TO UPPER 20C RANGE. WENT AHEAD AND RAISED POPS SUNDAY NIGHT INTO TUESDAY TO HIGH CHANCE ACROSS LAKE EFFECT PREFERRED AREAS. NO MAJOR CHANGES TO TEMPERATURES...AS THE ALLBLEND SOLUTIONS HAVE CAUGHT ON TO COLDER TEMPERATURES WITH THE ARRIVAL OF THE POLAR AIR MASS.&& && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 11 PM EST THIS EVENING FOR LMZ043. SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 5 PM EST THIS AFTERNOON FOR LMZ046. && $$ SHORT TERM...LOGSDON LONG TERM...NG UPDATE...MARSILI AVIATION...STEINWEDEL
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1158 AM CST THU DEC 29 2011 .AVIATION... CURRENTLY LOW PRESSURE IS SLIDING SOUTHEASTWARD ACROSS SOUTHERN WISCONSIN WITH IFR CEILINGS OVER CENTRAL MINNESOTA. VFR CONDITIONS ARE IN PLACE OVER EASTERN IOWA. IFR CEILINGS IN CENTRAL MINNESOTA ARE FORECAST TO REMAIN TO THE NORTH AND EAST OF KCID...KDBQ...KMLI...AND KBRL THIS AFTERNOON. CLOUD HEIGHTS WILL SLOWLY LOWER AS ANOTHER FAST MOVING STORM SYSTEM APPROACHES AND MOVES THROUGH THE REGION TONIGHT. RAIN IS EXPECTED TO DEVELOP BY 06 UTC WITH MVFR CEILINGS AT KCID...KDBQ...AND KMLI. KMLI IS ON THE SOUTHERN EDGE OF THE HEAVIER PRECIPITATION SO WENT WITH VCSH AFTER 14 UTC. CURRENTLY...RAIN IS EXPECTED TO TRANSITION TO SNOW AT KDBQ AFTER 12 UTC. ANY LINGERING PRECIPITATION WILL EXIT INTO WESTERN ILLINOIS BY 18 UTC WITH MVFR CEILINGS CONTINUING THROUGH 18 UTC AT ALL TAF SITES. ..JH/DC.. && PREV DISCUSSION... /ISSUED 652 AM CST THU DEC 29 2011/ UPDATE... A FEW SHRA/S HAVE DEVELOPED FROM NEAR QUAD CITIES S/E WITHIN AREA OF MID LEVEL INSTABILITY AHEAD OF VORT MAX. UPDATED TO ADD ISOLD MENTION AND SHOULD BE OUT OF CWA NEXT 1-2 HRS. NEXT CONCERN IS CLOUD TRENDS. LEADING EDGE OF STRATUS HAS DISSIPATED OVER SOUTHERN MN AND NOTICING PAST FEW HRS OF CIG TRENDS FROM RUC BACKUP MODEL KEEPS LOW CLOUDS TO N/W OF CWA TDY. THIS LOOKS REASONABLE GIVEN RECENT TRENDS PLUS THE ADDITIONAL RAPID EROSION TO STRATUS OVER ND DUE TO WARM ADVECTION ALOFT. WILL BE UPDATING TO BE MORE OPTIMISTIC WITH SKY COVER NORTH HALF AND TWEAK MAXES UP A COUPLE DEGS. PREV DISCUSSION... /ISSUED 411 AM CST THU DEC 29 2011/ SYNOPSIS... STARTING OUT THIS AM WITH TEMPS THAT ALREADY AT OR 5+ DEGS ABOVE NORMAL HIGHS. ALWAYS A GREAT SIGN AND HARBINGER OF WHAT IS TO COME TDY. QUASI-ZONAL FLOW FULL OF ENERGY EARLY THIS AM. WATER VAPOR IMAGERY AND PROFILERS DEPICT SHORTWAVE NEAR PICKLE LAKE ONTARIO (CYPL) WITH SECONDARY WAVE FURTHER SOUTH NEAR LACROSSE WI... BOTH SLIDING E/SE. ATTENDANT SFC LOW WAS LOCATED CLOSE TO SAINT CLOUD MN WITH COLD FRONT EXTENDING WNWD INTO NORTHERN SD WHILE WARM FRONT WAS DRAPED SEWD INTO EASTERN IA. WARM ADVECTION WING WITH JUST TRACE AMOUNTS OF PCPN PASSING QUICKLY THROUGH NORTHERN IL. MOST OBS THIS FAR SOUTH HAVE BEEN REPORTING SPRINKLES BUT A COUPLE OF QUESTION MARKS SHOWING ON SOME ASOS NEAR WI/IL BORDER INTO SOUTHERN WI AND SO CANT RULE OUT SOME FLAKES OR EVEN ICE PELLETS BUT NO GROUND TRUTH REPORTS. THIS WILL BE EXITING SHORTLY WITH SKIES CLEARING INTO EASTERN IA IN WAKE OF WARM ADVECTION. SATL SHOWS A LARGE AREA OF LOW CLOUDS OVER ND... FAR NORTHEAST SD AND WESTERN MN ON BACKSIDE OF SFC LOW IN LOW LEVEL COLD ADVECTION WHICH HAVE BEEN SLIDING SEWD. MEANWHILE... NEXT BARRAGE OF ENERGY IN VERY ENERGETIC PACIFIC WAVE TRAIN PLOWING THROUGH PACIFIC NW AND NORTHERN ROCKIES... AND ITS THIS ENERGY THAT WILL AID IN BRINGING PCPN TO PORTIONS OF THE REGION TNGT-FRI. SHORT TERM...TODAY AND TONIGHT... EYES ARE POINTED NW EARLY THIS AM. SFC LOW OVER CENTRAL MN TO DIVE E/SE THROUGH SOUTHERN WI TDY WITH TRAILING COLD FRONT SWEEPING ACROSS THE CWA. THUS... WARM ADVECTION ON GUSTY SW WINDS TO START OFF WILL EVENTUALLY BE REPLACED WITH COLD ADVECTION ON GUSTY W/NW WINDS. BEST COLD ADVECTION PROGGED NORTH THIRD TO HALF OF CWA WHERE ALSO EXPECT TO SEE SOME STRATUS TURNING SKIES FROM SUNNY TO PT-MOCLDY. TEMPS EVERYWHERE WELL ABOVE NORMAL BY CLOSE TO 15+ DEGS... WITH COOLEST READINGS NORTH WHERE WENT WITH AROUND 40/L40S DUE TO ANTICIPATION OF LOW CLOUDS BY MID-LATE AM. FROM THERE ON SOUTH TEMPS WARMING WELL INTO THE 40S WITH 50S OVER SE IA... WCNTRL IL AND NE MO. TNGT... ANOTHER DOUBLE BARREL ENERGY COMPLEX EXPECTED TO SHIFT FROM THE PLAINS INTO UPPER MIDWEST. ROBUST WARM ADVECTION TO GENERATE PCPN THAT WILL MOVE ACROSS MUCH OF AREA BY MID-LATE EVE AND OVRNGT ESPECIALLY NORTH OF KOTM-KBRL LINE. FCST SOUNDINGS AND LATEST SUITE OF SREF PTYPE PROBS ALL SUPPORT PCPN WILL BE RAIN. UKMET AND ECMWF STRONGER WITH ENERGY RESULTING IN DEEPER SFC LOW FOR EVEN WARMER DRAW AGAIN SUPPORTING RAIN AS THEY SHOW H85 LOW MOVING INTO NE IA 12Z FRI... PLACING BETTER SNOW CHCS NORTH OR LEFT OF THE H85 LOW TRACK. QPF AMOUNTS WILL BE LIGHT AND GENERALLY A TENTH OR TWO AT MOST. TEMPS WILL DROP OFF A BIT EARLY THIS EVE THEN BECOME STEADY AND SLOWLY RISE WITH ONSET OF LOW LEVEL WARM ADVECTION. ..05.. LONG TERM...FRIDAY THROUGH NEXT WEDNESDAY... FRIDAY...STILL SOME VARIANCE BETWEEN THE 00Z MODEL RUNS INTO FRI WITH HANDLING AND DEVELOPMENT OF THE PASSING WAVE COMPLEX. BUT WITH THE PROGRESSIVE NATURE OF THE CURRENT REGIME PATTERN WE HAVE BEEN IN THIS WEEK AND LOOKING AT UPPER JET DYNAMICS THROUGH FRI NIGHT... FEEL THE 00Z RUN GFS SOLUTION THE ONE TO FOLLOW FOR NOW THIS PERIOD. ALSO PREFER THE FURTHER NORTH LOW TO MID LEVEL WAVE PROGRESSION ACRS THE REGION IN LINGERING POSITIVE AO. THIS ACCEPTED GFS SOLUTION SUGGESTS BULK OF ANY PRECIP SHIELD ASSOCIATED WITH THE PASSING LOW WILL BE ON THE MOVE OUT OF THE DVN CWA FRI MORNING AFTER 12Z. WILL WALK OUT PRECIP IN THE MORE WITH LIKELY POPS IN THE FAR NORTHEAST... AND LESSER CHC POPS FURTHER TO THE WEST AND SOUTH. IT ALSO APPEARS IN-WRAPPING LLVL COLD CONVEYOR OR TOP-DOWN COOLING ENOUGH FOR A CHANGE OVER TO SNOW WILL OCCUR AFTER THE BULK OF ANY MEASURING PRECIP EXITS THE AREA AS WELL. BUT PROJECTED THERMAL PROFILES ARE CLOSE THROUGH 15Z FRI ALONG AND NORTH OF THE HWY 20 CORRIDOR AND WILL MENTION A MIX IN THOSE AREAS BUT WITH LITTLE IF ANY SNOW ACCUM. LOW TO MID LEVEL DRYING/RH DECREASE LATE MORNING THOUGH MIDDAY AS LOW CENTER PASSES...THEN SYSTEM WRAP AROUND STRATOCU ENGULFS MUCH OF THE CWA FRI AFTERNOON INTO THE EVENING. EXTENT OF PRECIP POTENTIAL IN THIS WRAP AROUND DECK UNCERTAIN ALONG WITH ADEQUATE MOISTURE DEPTH FOR MEASURABLE. FOR NOW WILL JUST GO WITH A SLIGHT CHC OF LIGHT RAIN OR LIGHT SNOW IN THE FAR NORTH FRI AFTERNOON...BUT IT MAY BE NOT MUCH MORE THAN FLURRIES OR SPRINKLES. FRI HIGHS RANGING FROM AROUND 40 IN THE FAR NORTH..TO NEAR 50 IN THE FAR SOUTH. THEN EXPECT THE CLOUDS TO CLEAR TO THE EAST FRI NIGHT WITH SFC WIND DROP OFF WITH PASSING SFC RIDGE LOBE. LOWS IN THE UPPER 20S TO LOWER 30S FOR NOW BUT IT MAY BE COOLER DEPENDING ON IF RETURN FLOW CAN COMMENCE TOWARD SAT MORNING IN TIME TO HALT THE TEMP DROP-OFF ESPECIALLY WEST OF THE MS RVR. SATURDAY AND SUNDAY...LOOKING AT THE LATEST 00Z RUN MEDIUM RANGE MODELS AND WARM UP POTENTIAL AHEAD OF A SUBSTANTIAL IMPULSE TRYING TO PHASE OVER THE MID CONUS ON SAT...DURATION OF THE WARM TONGUE AND MIXING DEPTH STILL AT QUESTION ENOUGH TO FUEL THE ADVERTISED DAY WELL IN THE 50S. WILL MAKE ONLY MINOR ADJUSTMENTS TO SAT HIGHS FOR NOW AS STILL SOMEWHAT HESITANT TO GO CRAZY WITH THE FULL WARM UP POTENTIAL. BUT EVEN WITH THE CURRENT PROJECTED THERMAL PROFILES AND FCST SOUNDINGS...JUST MIXING UP TO AROUND H9 MB/INTO BASE OF A VERY PRONOUNCED WARM WEDGE ALOFT/INVERSION CENTERED AROUND H85 MB...HIGHS WOULD BE IN THE MID 50S WITH A FEW LOCATIONS PUSHING THE UPPER 50S IN THE SOUTHWESTERN CWA. THE MODELS THEN REALLY START TO DIVERGE NEW YEARS EVE/SAT NIGHT WITH RESPECT TO CONTINUED DEVELOP OF A L/W TROF AND ASSOCIATED DEEPENING LLVL CYCLONE OVER THE UPPER MIDWEST AND NORTHWESTERN GRT LKS. BUT THE GENERAL ENSEMBLES SUGGEST THAT THE DVN CWA WILL REMAIN DRY SAT NIGHT AND MILD THROUGH MIDNIGHT/HELD UP WELL IN THE 40S BEFORE IN-SWIRLING COLD PUSH MAKES IT ACRS THE AREA FROM NW-TO-SE AFTER 09Z SUNDAY. STILL SOME DETAILS TO REFINE WITH THIS PERIOD OVER THE NEXT 24-36 HRS OF MODEL RUNS. AS FOR NEW YEARS DAY SUNDAY...A WINDY RAW DAY WITH MORNING HIGHS AND THEN FALLING TEMPS AS NORTHWEST SFC WINDS GUST OVER 30 MPH IN ROBUST CAA REGIME UNDER AMPLIFYING PATTERN. THE ECMWF STILL THE MOST DEVELOPED WITH HIGH AMPLITUDE NEAR MERIDIONAL FETCH DEVELOPING ACRS THE WESTERN GRT LKS BY MONDAY MORNING. H85 TEMPS BY 12Z MON IN NEGATIVE MID TEENS C AND LOWS SUNDAY NIGHT PROBABLY WELL DOWN IN THE TEENS DESPITE ONGOING MIXING WINDS OF 15-25 MPH EVEN AT NIGHT. WILL KEEP SUNDAY DRY BUT IN SUCH A REGIME WOULD EXPECT COL AIR STRATUS TO BLANKET THE AREA ALONG WITH SOME EMBEDDED FLURRIES. MONDAY THROUGH WEDNESDAY...WILL KEEP HIGH AMPLITUDE ARCTIC AIRMASS DUMP INTO THE MIDWEST GOING MON AND MON NIGHT. MONDAY HIGHS PROBABLY NOT TO GET OUT OF THE LOW TO MID 20S WITH ONGOING GUSTY NORTHWEST WINDS OF 20-30 MPH AND HIGHER GUSTS. SFC RIDGE LOBE SLIDING ACRS THE CWA...SFC WIND DECOUPLE AND STRATUS CLEAR OFF COULD FOSTER SINGLE DIGIT LOWS OVER SOME PORTIONS OF THE DVN CWA BY TUE MORNING EVEN OVER SNOWCOVER-LESS TERRAIN. AGAIN WILL GO DRY IN THE GRIDS ON MONDAY BUT WOULD BET SOME CAA FLURRIES CONTINUING TO GET MILKED OUT OF WHATEVER MOISTURE THERE IS ACRS THE AREA. LONGER RANGE SIGNALS SUGGEST THE FLOW WILL TRY TO FLATTEN OUT AGAIN TOWARD MID NEXT WEEK AS ARCTIC OSCILLATION/AO PROGS MIGRATE BACK TOWARD THE POSITIVE. BUT THERMAL MODERATION INTO TUE TO BE SLOW AND MORE REALIZED BY NEXT WED WITH HIGHS RETURNING TO THE MID AND UPPER 30S. THIS PROCESS MAY BE AIDED BY A WARM DRAW TO THE SOUTH OF CLIPPER TYPE SYSTEM DROPPING FROM SASKATCHEWAN TO WI SOMETIME DURING THIS TUE INTO WED PERIOD. ..12.. AVIATION... /ISSUED 1137 PM CST WED DEC 28 2011/ && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
858 AM CST THU DEC 29 2011 .AVIATION... CURRENTLY VFR CEILINGS ACROSS THE MID MISSISSIPPI VALLEY THIS MORNING WITH MVFR TO IFR CEILINGS ACROSS CENTRAL MINNESOTA. UPDATED THE PREVIOUS SET OF TAFS TO REMOVE MVFR CEILINS AT KDBQ AS AS THE LOWER CEILINGS ARE EXPECTED TO REMAIN TO THE NORTH AND EAST OF THESE TAF SITES. DC/JH && .PREV DISCUSSION... /ISSUED 652 AM CST THU DEC 29 2011/ UPDATE... A FEW SHRA/S HAVE DEVELOPED FROM NEAR QUAD CITIES S/E WITHIN AREA OF MID LEVEL INSTABILITY AHEAD OF VORT MAX. UPDATED TO ADD ISOLD MENTION AND SHOULD BE OUT OF CWA NEXT 1-2 HRS. NEXT CONCERN IS CLOUD TRENDS. LEADING EDGE OF STRATUS HAS DISSIPATED OVER SOUTHERN MN AND NOTICING PAST FEW HRS OF CIG TRENDS FROM RUC BACKUP MODEL KEEPS LOW CLOUDS TO N/W OF CWA TDY. THIS LOOKS REASONABLE GIVEN RECENT TRENDS PLUS THE ADDITIONAL RAPID EROSION TO STRATUS OVER ND DUE TO WARM ADVECTION ALOFT. WILL BE UPDATING TO BE MORE OPTIMISTIC WITH SKY COVER NORTH HALF AND TWEAK MAXES UP A COUPLE DEGS. PREV DISCUSSION... /ISSUED 411 AM CST THU DEC 29 2011/ SYNOPSIS... STARTING OUT THIS AM WITH TEMPS THAT ALREADY AT OR 5+ DEGS ABOVE NORMAL HIGHS. ALWAYS A GREAT SIGN AND HARBINGER OF WHAT IS TO COME TDY. QUASI-ZONAL FLOW FULL OF ENERGY EARLY THIS AM. WATER VAPOR IMAGERY AND PROFILERS DEPICT SHORTWAVE NEAR PICKLE LAKE ONTARIO (CYPL) WITH SECONDARY WAVE FURTHER SOUTH NEAR LACROSSE WI... BOTH SLIDING E/SE. ATTENDANT SFC LOW WAS LOCATED CLOSE TO SAINT CLOUD MN WITH COLD FRONT EXTENDING WNWD INTO NORTHERN SD WHILE WARM FRONT WAS DRAPED SEWD INTO EASTERN IA. WARM ADVECTION WING WITH JUST TRACE AMOUNTS OF PCPN PASSING QUICKLY THROUGH NORTHERN IL. MOST OBS THIS FAR SOUTH HAVE BEEN REPORTING SPRINKLES BUT A COUPLE OF QUESTION MARKS SHOWING ON SOME ASOS NEAR WI/IL BORDER INTO SOUTHERN WI AND SO CANT RULE OUT SOME FLAKES OR EVEN ICE PELLETS BUT NO GROUND TRUTH REPORTS. THIS WILL BE EXITING SHORTLY WITH SKIES CLEARING INTO EASTERN IA IN WAKE OF WARM ADVECTION. SATL SHOWS A LARGE AREA OF LOW CLOUDS OVER ND... FAR NORTHEAST SD AND WESTERN MN ON BACKSIDE OF SFC LOW IN LOW LEVEL COLD ADVECTION WHICH HAVE BEEN SLIDING SEWD. MEANWHILE... NEXT BARRAGE OF ENERGY IN VERY ENERGETIC PACIFIC WAVE TRAIN PLOWING THROUGH PACIFIC NW AND NORTHERN ROCKIES... AND ITS THIS ENERGY THAT WILL AID IN BRINGING PCPN TO PORTIONS OF THE REGION TNGT-FRI. SHORT TERM...TODAY AND TONIGHT... EYES ARE POINTED NW EARLY THIS AM. SFC LOW OVER CENTRAL MN TO DIVE E/SE THROUGH SOUTHERN WI TDY WITH TRAILING COLD FRONT SWEEPING ACROSS THE CWA. THUS... WARM ADVECTION ON GUSTY SW WINDS TO START OFF WILL EVENTUALLY BE REPLACED WITH COLD ADVECTION ON GUSTY W/NW WINDS. BEST COLD ADVECTION PROGGED NORTH THIRD TO HALF OF CWA WHERE ALSO EXPECT TO SEE SOME STRATUS TURNING SKIES FROM SUNNY TO PT-MOCLDY. TEMPS EVERYWHERE WELL ABOVE NORMAL BY CLOSE TO 15+ DEGS... WITH COOLEST READINGS NORTH WHERE WENT WITH AROUND 40/L40S DUE TO ANTICIPATION OF LOW CLOUDS BY MID-LATE AM. FROM THERE ON SOUTH TEMPS WARMING WELL INTO THE 40S WITH 50S OVER SE IA... WCNTRL IL AND NE MO. TNGT... ANOTHER DOUBLE BARREL ENERGY COMPLEX EXPECTED TO SHIFT FROM THE PLAINS INTO UPPER MIDWEST. ROBUST WARM ADVECTION TO GENERATE PCPN THAT WILL MOVE ACROSS MUCH OF AREA BY MID-LATE EVE AND OVRNGT ESPECIALLY NORTH OF KOTM-KBRL LINE. FCST SOUNDINGS AND LATEST SUITE OF SREF PTYPE PROBS ALL SUPPORT PCPN WILL BE RAIN. UKMET AND ECMWF STRONGER WITH ENERGY RESULTING IN DEEPER SFC LOW FOR EVEN WARMER DRAW AGAIN SUPPORTING RAIN AS THEY SHOW H85 LOW MOVING INTO NE IA 12Z FRI... PLACING BETTER SNOW CHCS NORTH OR LEFT OF THE H85 LOW TRACK. QPF AMOUNTS WILL BE LIGHT AND GENERALLY A TENTH OR TWO AT MOST. TEMPS WILL DROP OFF A BIT EARLY THIS EVE THEN BECOME STEADY AND SLOWLY RISE WITH ONSET OF LOW LEVEL WARM ADVECTION. ..05.. LONG TERM...FRIDAY THROUGH NEXT WEDNESDAY... FRIDAY...STILL SOME VARIANCE BETWEEN THE 00Z MODEL RUNS INTO FRI WITH HANDLING AND DEVELOPMENT OF THE PASSING WAVE COMPLEX. BUT WITH THE PROGRESSIVE NATURE OF THE CURRENT REGIME PATTERN WE HAVE BEEN IN THIS WEEK AND LOOKING AT UPPER JET DYNAMICS THROUGH FRI NIGHT... FEEL THE 00Z RUN GFS SOLUTION THE ONE TO FOLLOW FOR NOW THIS PERIOD. ALSO PREFER THE FURTHER NORTH LOW TO MID LEVEL WAVE PROGRESSION ACRS THE REGION IN LINGERING POSITIVE AO. THIS ACCEPTED GFS SOLUTION SUGGESTS BULK OF ANY PRECIP SHIELD ASSOCIATED WITH THE PASSING LOW WILL BE ON THE MOVE OUT OF THE DVN CWA FRI MORNING AFTER 12Z. WILL WALK OUT PRECIP IN THE MORE WITH LIKELY POPS IN THE FAR NORTHEAST... AND LESSER CHC POPS FURTHER TO THE WEST AND SOUTH. IT ALSO APPEARS IN-WRAPPING LLVL COLD CONVEYOR OR TOP-DOWN COOLING ENOUGH FOR A CHANGE OVER TO SNOW WILL OCCUR AFTER THE BULK OF ANY MEASURING PRECIP EXITS THE AREA AS WELL. BUT PROJECTED THERMAL PROFILES ARE CLOSE THROUGH 15Z FRI ALONG AND NORTH OF THE HWY 20 CORRIDOR AND WILL MENTION A MIX IN THOSE AREAS BUT WITH LITTLE IF ANY SNOW ACCUM. LOW TO MID LEVEL DRYING/RH DECREASE LATE MORNING THOUGH MIDDAY AS LOW CENTER PASSES...THEN SYSTEM WRAP AROUND STRATOCU ENGULFS MUCH OF THE CWA FRI AFTERNOON INTO THE EVENING. EXTENT OF PRECIP POTENTIAL IN THIS WRAP AROUND DECK UNCERTAIN ALONG WITH ADEQUATE MOISTURE DEPTH FOR MEASURABLE. FOR NOW WILL JUST GO WITH A SLIGHT CHC OF LIGHT RAIN OR LIGHT SNOW IN THE FAR NORTH FRI AFTERNOON...BUT IT MAY BE NOT MUCH MORE THAN FLURRIES OR SPRINKLES. FRI HIGHS RANGING FROM AROUND 40 IN THE FAR NORTH..TO NEAR 50 IN THE FAR SOUTH. THEN EXPECT THE CLOUDS TO CLEAR TO THE EAST FRI NIGHT WITH SFC WIND DROP OFF WITH PASSING SFC RIDGE LOBE. LOWS IN THE UPPER 20S TO LOWER 30S FOR NOW BUT IT MAY BE COOLER DEPENDING ON IF RETURN FLOW CAN COMMENCE TOWARD SAT MORNING IN TIME TO HALT THE TEMP DROP-OFF ESPECIALLY WEST OF THE MS RVR. SATURDAY AND SUNDAY...LOOKING AT THE LATEST 00Z RUN MEDIUM RANGE MODELS AND WARM UP POTENTIAL AHEAD OF A SUBSTANTIAL IMPULSE TRYING TO PHASE OVER THE MID CONUS ON SAT...DURATION OF THE WARM TONGUE AND MIXING DEPTH STILL AT QUESTION ENOUGH TO FUEL THE ADVERTISED DAY WELL IN THE 50S. WILL MAKE ONLY MINOR ADJUSTMENTS TO SAT HIGHS FOR NOW AS STILL SOMEWHAT HESITANT TO GO CRAZY WITH THE FULL WARM UP POTENTIAL. BUT EVEN WITH THE CURRENT PROJECTED THERMAL PROFILES AND FCST SOUNDINGS...JUST MIXING UP TO AROUND H9 MB/INTO BASE OF A VERY PRONOUNCED WARM WEDGE ALOFT/INVERSION CENTERED AROUND H85 MB...HIGHS WOULD BE IN THE MID 50S WITH A FEW LOCATIONS PUSHING THE UPPER 50S IN THE SOUTHWESTERN CWA. THE MODELS THEN REALLY START TO DIVERGE NEW YEARS EVE/SAT NIGHT WITH RESPECT TO CONTINUED DEVELOP OF A L/W TROF AND ASSOCIATED DEEPENING LLVL CYCLONE OVER THE UPPER MIDWEST AND NORTHWESTERN GRT LKS. BUT THE GENERAL ENSEMBLES SUGGEST THAT THE DVN CWA WILL REMAIN DRY SAT NIGHT AND MILD THROUGH MIDNIGHT/HELD UP WELL IN THE 40S BEFORE IN-SWIRLING COLD PUSH MAKES IT ACRS THE AREA FROM NW-TO-SE AFTER 09Z SUNDAY. STILL SOME DETAILS TO REFINE WITH THIS PERIOD OVER THE NEXT 24-36 HRS OF MODEL RUNS. AS FOR NEW YEARS DAY SUNDAY...A WINDY RAW DAY WITH MORNING HIGHS AND THEN FALLING TEMPS AS NORTHWEST SFC WINDS GUST OVER 30 MPH IN ROBUST CAA REGIME UNDER AMPLIFYING PATTERN. THE ECMWF STILL THE MOST DEVELOPED WITH HIGH AMPLITUDE NEAR MERIDIONAL FETCH DEVELOPING ACRS THE WESTERN GRT LKS BY MONDAY MORNING. H85 TEMPS BY 12Z MON IN NEGATIVE MID TEENS C AND LOWS SUNDAY NIGHT PROBABLY WELL DOWN IN THE TEENS DESPITE ONGOING MIXING WINDS OF 15-25 MPH EVEN AT NIGHT. WILL KEEP SUNDAY DRY BUT IN SUCH A REGIME WOULD EXPECT COL AIR STRATUS TO BLANKET THE AREA ALONG WITH SOME EMBEDDED FLURRIES. MONDAY THROUGH WEDNESDAY...WILL KEEP HIGH AMPLITUDE ARCTIC AIRMASS DUMP INTO THE MIDWEST GOING MON AND MON NIGHT. MONDAY HIGHS PROBABLY NOT TO GET OUT OF THE LOW TO MID 20S WITH ONGOING GUSTY NORTHWEST WINDS OF 20-30 MPH AND HIGHER GUSTS. SFC RIDGE LOBE SLIDING ACRS THE CWA...SFC WIND DECOUPLE AND STRATUS CLEAR OFF COULD FOSTER SINGLE DIGIT LOWS OVER SOME PORTIONS OF THE DVN CWA BY TUE MORNING EVEN OVER SNOWCOVER-LESS TERRAIN. AGAIN WILL GO DRY IN THE GRIDS ON MONDAY BUT WOULD BET SOME CAA FLURRIES CONTINUING TO GET MILKED OUT OF WHATEVER MOISTURE THERE IS ACRS THE AREA. LONGER RANGE SIGNALS SUGGEST THE FLOW WILL TRY TO FLATTEN OUT AGAIN TOWARD MID NEXT WEEK AS ARCTIC OSCILLATION/AO PROGS MIGRATE BACK TOWARD THE POSITIVE. BUT THERMAL MODERATION INTO TUE TO BE SLOW AND MORE REALIZED BY NEXT WED WITH HIGHS RETURNING TO THE MID AND UPPER 30S. THIS PROCESS MAY BE AIDED BY A WARM DRAW TO THE SOUTH OF CLIPPER TYPE SYSTEM DROPPING FROM SASKATCHEWAN TO WI SOMETIME DURING THIS TUE INTO WED PERIOD. ..12.. AVIATION... /ISSUED 1137 PM CST WED DEC 28 2011/ && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
652 AM CST THU DEC 29 2011 .UPDATE... A FEW SHRA/S HAVE DEVELOPED FROM NEAR QUAD CITIES S/E WITHIN AREA OF MID LEVEL INSTABILTY AHEAD OF VORT MAX. UPDATED TO ADD ISOLD MENTION AND SHOULD BE OUT OF CWA NEXT 1-2 HRS. NEXT CONCERN IS CLOUD TRENDS. LEADING EDGE OF STRATUS HAS DISSIPATED OVER SOUTHERN MN AND NOTICING PAST FEW HRS OF CIG TRENDS FROM RUC BACKUP MODEL KEEPS LOW CLOUDS TO N/W OF CWA TDY. THIS LOOKS REASONABLE GIVEN RECENT TRENDS PLUS THE ADDITIONAL RAPID EROSION TO STRATUS OVER ND DUE TO WARM ADVECTION ALOFT. WILL BE UPDATING TO BE MORE OPTIMISTIC WITH SKY COVER NORTH HALF AND TWEAK MAXES UP A COUPLE DEGS. && .AVIATION... /ISSUED 558 AM CST THU DEC 29 2011/ CURRENTLY..WEAK RETURNS ARE SHOWING UP ON RADAR IN THE VICINITY OF KBRL AND KMLI AND MAY AFFECT THESE TERMINALS THROUGH 13 UTC. MVFR CEILINGS IN THE WAKE OF THIS MORINGS CLIPPER SYSTEM WILL BRUSH KDBQ BETWEEN 15 AND 18 UTC WITH SCT CEILINGS AT KCID. AFTER 18 UTC ALL TAF SITES WILL BE VFR THROUGH 03 UTC WHEN A MUCH STRONGER CLIPPER SYSTEM APPROACHES THE MID MISSISSIPPI VALLEY. MVFR CEILINGS MOVE INTO KCID AND KDBQ BY 06 UTC WITH PERIODS OF RAIN THROUGH THE END OF THE PERIOD. RAIN WILL NOT BE AS WIDESPREAD AT KBRL AND KMLI AND MAY ONLY OCCURR FOR A BRIEF PERIOD SO USED VCSH AS TIMING IS UNCERTAIN AND LEFT CEILINGS AT VFR WITH BETTER LOW LEVEL MOISTURE TO THE NORTH AND EAST. ..DC/MM.. && .PREV DISCUSSION... /ISSUED 411 AM CST THU DEC 29 2011/ SYNOPSIS... STARTING OUT THIS AM WITH TEMPS THAT ALREADY AT OR 5+ DEGS ABOVE NORMAL HIGHS. ALWAYS A GREAT SIGN AND HARBINGER OF WHAT IS TO COME TDY. QUASI-ZONAL FLOW FULL OF ENERGY EARLY THIS AM. WATER VAPOR IMAGERY AND PROFILERS DEPICT SHORTWAVE NEAR PICKLE LAKE ONTARIO (CYPL) WITH SECONDARY WAVE FURTHER SOUTH NEAR LACROSSE WI... BOTH SLIDING E/SE. ATTENDANT SFC LOW WAS LOCATED CLOSE TO SAINT CLOUD MN WITH COLD FRONT EXTENDING WNWD INTO NORTHERN SD WHILE WARM FRONT WAS DRAPED SEWD INTO EASTERN IA. WARM ADVECTION WING WITH JUST TRACE AMOUNTS OF PCPN PASSING QUICKLY THROUGH NORTHERN IL. MOST OBS THIS FAR SOUTH HAVE BEEN REPORTING SPRINKLES BUT A COUPLE OF QUESTION MARKS SHOWING ON SOME ASOS NEAR WI/IL BORDER INTO SOUTHERN WI AND SO CANT RULE OUT SOME FLAKES OR EVEN ICE PELLETS BUT NO GROUND TRUTH REPORTS. THIS WILL BE EXITING SHORTLY WITH SKIES CLEARING INTO EASTERN IA IN WAKE OF WARM ADVECTION. SATL SHOWS A LARGE AREA OF LOW CLOUDS OVER ND... FAR NORTHEAST SD AND WESTERN MN ON BACKSIDE OF SFC LOW IN LOW LEVEL COLD ADVECTION WHICH HAVE BEEN SLIDING SEWD. MEANWHILE... NEXT BARRAGE OF ENERGY IN VERY ENERGETIC PACIFIC WAVE TRAIN PLOWING THROUGH PACIFIC NW AND NORTHERN ROCKIES... AND ITS THIS ENERGY THAT WILL AID IN BRINGING PCPN TO PORTIONS OF THE REGION TNGT-FRI. SHORT TERM...TODAY AND TONIGHT... EYES ARE POINTED NW EARLY THIS AM. SFC LOW OVER CENTRAL MN TO DIVE E/SE THROUGH SOUTHERN WI TDY WITH TRAILING COLD FRONT SWEEPING ACROSS THE CWA. THUS... WARM ADVECTION ON GUSTY SW WINDS TO START OFF WILL EVENTUALLY BE REPLACED WITH COLD ADVECTION ON GUSTY W/NW WINDS. BEST COLD ADVECTION PROGGED NORTH THIRD TO HALF OF CWA WHERE ALSO EXPECT TO SEE SOME STRATUS TURNING SKIES FROM SUNNY TO PT-MOCLDY. TEMPS EVERYWHERE WELL ABOVE NORMAL BY CLOSE TO 15+ DEGS... WITH COOLEST READINGS NORTH WHERE WENT WITH AROUND 40/L40S DUE TO ANTICIPATION OF LOW CLOUDS BY MID-LATE AM. FROM THERE ON SOUTH TEMPS WARMING WELL INTO THE 40S WITH 50S OVER SE IA... WCNTRL IL AND NE MO. TNGT... ANOTHER DOUBLE BARREL ENERGY COMPLEX EXPECTED TO SHIFT FROM THE PLAINS INTO UPPER MIDWEST. ROBUST WARM ADVECTION TO GENERATE PCPN THAT WILL MOVE ACROSS MUCH OF AREA BY MID-LATE EVE AND OVRNGT ESPECIALLY NORTH OF KOTM-KBRL LINE. FCST SOUNDINGS AND LATEST SUITE OF SREF PTYPE PROBS ALL SUPPORT PCPN WILL BE RAIN. UKMET AND ECMWF STRONGER WITH ENERGY RESULTING IN DEEPER SFC LOW FOR EVEN WARMER DRAW AGAIN SUPPORTING RAIN AS THEY SHOW H85 LOW MOVING INTO NE IA 12Z FRI... PLACING BETTER SNOW CHCS NORTH OR LEFT OF THE H85 LOW TRACK. QPF AMOUNTS WILL BE LIGHT AND GENERALLY A TENTH OR TWO AT MOST. TEMPS WILL DROP OFF A BIT EARLY THIS EVE THEN BECOME STEADY AND SLOWLY RISE WITH ONSET OF LOW LEVEL WARM ADVECTION. ..05.. LONG TERM...FRIDAY THROUGH NEXT WEDNESDAY... FRIDAY...STILL SOME VARIANCE BETWEEN THE 00Z MODEL RUNS INTO FRI WITH HANDLING AND DEVELOPMENT OF THE PASSING WAVE COMPLEX. BUT WITH THE PROGRESSIVE NATURE OF THE CURRENT REGIME PATTERN WE HAVE BEEN IN THIS WEEK AND LOOKING AT UPPER JET DYNAMICS THROUGH FRI NIGHT... FEEL THE 00Z RUN GFS SOLUTION THE ONE TO FOLLOW FOR NOW THIS PERIOD. ALSO PREFER THE FURTHER NORTH LOW TO MID LEVEL WAVE PROGRESSION ACRS THE REGION IN LINGERING POSITIVE AO. THIS ACCEPTED GFS SOLUTION SUGGESTS BULK OF ANY PRECIP SHIELD ASSOCIATED WITH THE PASSING LOW WILL BE ON THE MOVE OUT OF THE DVN CWA FRI MORNING AFTER 12Z. WILL WALK OUT PRECIP IN THE MORE WITH LIKELY POPS IN THE FAR NORTHEAST... AND LESSER CHC POPS FURTHER TO THE WEST AND SOUTH. IT ALSO APPEARS IN-WRAPPING LLVL COLD CONVEYOR OR TOP-DOWN COOLING ENOUGH FOR A CHANGE OVER TO SNOW WILL OCCUR AFTER THE BULK OF ANY MEASURING PRECIP EXITS THE AREA AS WELL. BUT PROJECTED THERMAL PROFILES ARE CLOSE THROUGH 15Z FRI ALONG AND NORTH OF THE HWY 20 CORRIDOR AND WILL MENTION A MIX IN THOSE AREAS BUT WITH LITTLE IF ANY SNOW ACCUM. LOW TO MID LEVEL DRYING/RH DECREASE LATE MORNING THOUGH MIDDAY AS LOW CENTER PASSES...THEN SYSTEM WRAP AROUND STRATOCU ENGULFS MUCH OF THE CWA FRI AFTERNOON INTO THE EVENING. EXTENT OF PRECIP POTENTIAL IN THIS WRAP AROUND DECK UNCERTAIN ALONG WITH ADEQUATE MOISTURE DEPTH FOR MEASURABLE. FOR NOW WILL JUST GO WITH A SLIGHT CHC OF LIGHT RAIN OR LIGHT SNOW IN THE FAR NORTH FRI AFTERNOON...BUT IT MAY BE NOT MUCH MORE THAN FLURRIES OR SPRINKLES. FRI HIGHS RANGING FROM AROUND 40 IN THE FAR NORTH..TO NEAR 50 IN THE FAR SOUTH. THEN EXPECT THE CLOUDS TO CLEAR TO THE EAST FRI NIGHT WITH SFC WIND DROP OFF WITH PASSING SFC RIDGE LOBE. LOWS IN THE UPPER 20S TO LOWER 30S FOR NOW BUT IT MAY BE COOLER DEPENDING ON IF RETURN FLOW CAN COMMENCE TOWARD SAT MORNING IN TIME TO HALT THE TEMP DROP-OFF ESPECIALLY WEST OF THE MS RVR. SATURDAY AND SUNDAY...LOOKING AT THE LATEST 00Z RUN MEDIUM RANGE MODELS AND WARM UP POTENTIAL AHEAD OF A SUBSTANTIAL IMPULSE TRYING TO PHASE OVER THE MID CONUS ON SAT...DURATION OF THE WARM TONGUE AND MIXING DEPTH STILL AT QUESTION ENOUGH TO FUEL THE ADVERTISED DAY WELL IN THE 50S. WILL MAKE ONLY MINOR ADJUSTMENTS TO SAT HIGHS FOR NOW AS STILL SOMEWHAT HESITANT TO GO CRAZY WITH THE FULL WARM UP POTENTIAL. BUT EVEN WITH THE CURRENT PROJECTED THERMAL PROFILES AND FCST SOUNDINGS...JUST MIXING UP TO AROUND H9 MB/INTO BASE OF A VERY PRONOUNCED WARM WEDGE ALOFT/INVERSION CENTERED AROUND H85 MB...HIGHS WOULD BE IN THE MID 50S WITH A FEW LOCATIONS PUSHING THE UPPER 50S IN THE SOUTHWESTERN CWA. THE MODELS THEN REALLY START TO DIVERGE NEW YEARS EVE/SAT NIGHT WITH RESPECT TO CONTINUED DEVELOP OF A L/W TROF AND ASSOCIATED DEEPENING LLVL CYCLONE OVER THE UPPER MIDWEST AND NORTHWESTERN GRT LKS. BUT THE GENERAL ENSEMBLES SUGGEST THAT THE DVN CWA WILL REMAIN DRY SAT NIGHT AND MILD THROUGH MIDNIGHT/HELD UP WELL IN THE 40S BEFORE IN-SWIRLING COLD PUSH MAKES IT ACRS THE AREA FROM NW-TO-SE AFTER 09Z SUNDAY. STILL SOME DETAILS TO REFINE WITH THIS PERIOD OVER THE NEXT 24-36 HRS OF MODEL RUNS. AS FOR NEW YEARS DAY SUNDAY...A WINDY RAW DAY WITH MORNING HIGHS AND THEN FALLING TEMPS AS NORTHWEST SFC WINDS GUST OVER 30 MPH IN ROBUST CAA REGIME UNDER AMPLIFYING PATTERN. THE ECMWF STILL THE MOST DEVELOPED WITH HIGH AMPLITUDE NEAR MERIDIONAL FETCH DEVELOPING ACRS THE WESTERN GRT LKS BY MONDAY MORNING. H85 TEMPS BY 12Z MON IN NEGATIVE MID TEENS C AND LOWS SUNDAY NIGHT PROBABLY WELL DOWN IN THE TEENS DESPITE ONGOING MIXING WINDS OF 15-25 MPH EVEN AT NIGHT. WILL KEEP SUNDAY DRY BUT IN SUCH A REGIME WOULD EXPECT COL AIR STRATUS TO BLANKET THE AREA ALONG WITH SOME EMBEDDED FLURRIES. MONDAY THROUGH WEDNESDAY...WILL KEEP HIGH AMPLITUDE ARCTIC AIRMASS DUMP INTO THE MIDWEST GOING MON AND MON NIGHT. MONDAY HIGHS PROBABLY NOT TO GET OUT OF THE LOW TO MID 20S WITH ONGOING GUSTY NORTHWEST WINDS OF 20-30 MPH AND HIGHER GUSTS. SFC RIDGE LOBE SLIDING ACRS THE CWA...SFC WIND DECOUPLE AND STRATUS CLEAR OFF COULD FOSTER SINGLE DIGIT LOWS OVER SOME PORTIONS OF THE DVN CWA BY TUE MORNING EVEN OVER SNOWCOVER-LESS TERRAIN. AGAIN WILL GO DRY IN THE GRIDS ON MONDAY BUT WOULD BET SOME CAA FLURRIES CONTINUING TO GET MILKED OUT OF WHATEVER MOISTURE THERE IS ACRS THE AREA. LONGER RANGE SIGNALS SUGGEST THE FLOW WILL TRY TO FLATTEN OUT AGAIN TOWARD MID NEXT WEEK AS ARCTIC OSCILLATION/AO PROGS MIGRATE BACK TOWARD THE POSITIVE. BUT THERMAL MODERATION INTO TUE TO BE SLOW AND MORE REALIZED BY NEXT WED WITH HIGHS RETURNING TO THE MID AND UPPER 30S. THIS PROCESS MAY BE AIDED BY A WARM DRAW TO THE SOUTH OF CLIPPER TYPE SYSTEM DROPPING FROM SASKATCHEWAN TO WI SOMETIME DURING THIS TUE INTO WED PERIOD. ..12.. AVIATION... /ISSUED 1137 PM CST WED DEC 28 2011/ && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
219 AM MST THU DEC 29 2011 .SHORT TERM (TODAY-SATURDAY)... 218 AM MST THU DEC 29 2011 WINDS AND TEMPERATURES ARE THE CHALLENGES WITH THE SHORT TERM PART OF THE FORECAST. FAST MOVING SHORT WAVE TROUGH WILL MOVE ACROSS THE NEBRASKA PANHANDLE AFTER 18Z TODAY. ONLY EXPECT TO SEE INCREASING CIRRUS CLOUDS WITH THE FEATURE AS BEST DIFFERENTIAL CYCLONIC VORTICITY ADVECTION WILL BE NORTH OF AREA. 850 MB ANALYSIS SHOWED 8 DEGREE CELSIUS TEMPERATURES FROM KDDC TO KLBF...AND MOST MODELS AGREE THAT TEMPERATURES WILL REACH 12-14 DEGREES CELSIUS BY THIS AFTERNOON. THIS WILL PRODUCE TEMPERATURES IN THE LOW TO MID 60S...EXCEPT AREAS SOUTH OF INTERSTATE 70 THAT ARE STILL IMPACTED BY SNOW COVER. MAY NOT HAVE THE BENEFIT OF FULL SOLAR INSOLATION GIVEN INCREASING HIGH LEVEL CLOUDS..BY HIGHS TODAY COULD BE CLOSE TO RECORDS. THE RECORD HIGH AT KITR IS 63 WHICH IS WITHIN REACH. WINDS TODAY ARE PROBLEMATIC. THERE IS DECENT POTENTIAL FOR MIXING...AND 850 MB WINDS WILL BE 30-40 KNOTS. SURFACE GRADIENT IS NOT IMPRESSIVE...HOWEVER... AND WILL ONLY MENTION BREEZY CONDITIONS TODAY THOUGH THE NEBRASKA COUNTIES MAY HAVE HIGHER GUSTS WHERE 850 MB WINDS WILL BE THE STRONGEST. FIRST SHORT WAVE MOVES EAST TONIGHT...BUT PUSHES COOLER AIR ACROSS THE FORECAST AREA. TEMPERATURES FRIDAY WILL BE 5-10 DEGREES COOLER. NEXT SHORTWAVE TROUGH MOVES OVER THE NORTHERN ROCKIES FRIDAY NIGHT. IT WILL BE STRONGER AND FURTHER SOUTH THAN THE PRIOR FEATURE...BUT MOISTURE WILL CONTINUE TO BE LIMITED THIS FAR SOUTH. AN ASSOCIATED COLD FRONT WILL MOVE THROUGH THE AREA SATURDAY. TIMING IS STILL UNCERTAIN...BUT 18Z SATURDAY AFTERNOON IS A LOGICAL STARTING POINT FOR FRONTAL PASSAGE AT KGLD. HOWEVER...DEPENDING ON THE TIMING... TEMPERATURES MAY WARM INTO THE MID 50S...OR NOT EVEN REACH THE 50S. HAVE TRENDED TEMPERATURES DOWN FOR SATURDAY AFTERNOON...BUT SUBSEQUENT MODEL RUNS WILL PROVIDE A CLEARER PICTURE ABOUT TEMPERATURES. IT SEEMS A GIVEN...HOWEVER...THAT WINDS BEHIND THE FRONT WILL BE STRONG. HAVE REALLY BOOSTED THE FORECASTED WINDS SATURDAY AFTERNOON...AND WOULD NOT BE SURPRISED TO SEE A WIND HIGHLIGHT EVENTUALLY BE ISSUED. && .LONG TERM (SUNDAY-WEDNESDAY)... 218 AM MST THU DEC 29 2011 SUNDAY THROUGH WEDNESDAY...DID NOT MAKE ANY CHANGES FROM INITIALIZED GRIDS SINCE THEY LOOK REASONABLE AT THIS TIME. HOWEVER... DETERMINISTIC AND ENSEMBLE MODEL OUTPUT ARE NOT IN VERY GOOD AGREEMENT WITH THE MID/UPPER PATTERN...MAINLY FOR THE SUNDAY INTO TUESDAY TIME PERIOD. ONE THING FOR SURE...NO MATTER WHICH MODEL ONE USES THE PATTERN IS A DRY ONE...AND GRIDS REFLECT THAT. WHERE THE DIFFERENCES ALOFT CAUSE PROBLEMS IS WITH THE SURFACE WIND AND TEMPERATURE FORECASTS. ON SUNDAY TEMPERATURES WILL BE COOLER THAN SATURDAY DUE TO A COLD FRONT MOVING THROUGH ON SATURDAY. HOWEVER...DIFFERENCES IN HOW COLD THE MODELS MAKE IT SHOW UP. CANADIAN IS MUCH COLDER...THE GFS THE WARMEST AND THE ECMWF SLIGHTLY COLDER THAN THE GFS. DUE TO MODEL DIFFERENCES AND SNOW FIELD...LEFT CURRENT MAXES ALONE BUT POTENTIAL IS THERE FOR IT TO BE COOLER. ON MONDAY...RETURN FLOW BEGINS AND WOULD EXPECT SOME WARMING. HOWEVER THIS FLOW IS COMING OVER SUBSTANTIAL SNOWFIELD TO OUR SOUTH AND SURFACE HIGH IS NOT THAT FAR AWAY. POTENTIAL IS THERE FOR IT BEING COOLER THAN WHAT IS IN THERE. DEPENDING ON WHICH MODEL YOU CHOOSE...THERE LOOKS TO BE ANOTHER COOL SURGE MOVING THROUGH TUESDAY INTO TUESDAY NIGHT WHICH COULD CAUSE THE HIGH TEMPERATURES TO BE COOLER THAN THE RATHER MILD/ABOVE NORMAL TEMPERATURES THAT ARE IN THERE FOR TUESDAY AND WEDNESDAY. ALSO HOW MUCH OF THE SNOW FIELD REMAINS WILL ALSO BE A FACTOR IN THE WARM UP. && .AVIATION... 1020 PM MST WED DEC 28 2011 FOR THE 06Z TAFS AT KGLD AND KMCK...VFR THROUGH THE PERIOD. WEST WINDS OF 10-15KTS EXPECTED THROUGH 18Z THEN INCREASING SLIGHTLY WITH GUSTS 25KTS OR SO AS A SFC TROUGH MOVES THROUGH. STILL SOME UNCERTAINTY AS TO WHETHER THE STRONGER WINDS ALOFT MIX DOWN AS LATEST RUC MODEL SHOWING SUSTAINED WINDS AT KGLD AROUND 20-25KTS WITH HIGHER GUSTS BY 20Z. BY 00Z WINDS BACK OFF WITH SPEEDS 10-15KTS. CLOUDINESS WILL BE LIMITED TO MID AND UPPER LEVELS. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1020 PM MST WED DEC 28 2011 .DISCUSSION... 224 PM MST WED DEC 28 2011 A SERIES OF SHORT WAVE TROUGHS ALOFT...AND THEIR ACCOMPANYING SURFACE SYSTEMS...ARE FORECAST TO MOVE RAPIDLY SOUTHEAST ACROSS THE NORTHERN PLAINS THROUGH FRIDAY. PRECIPITATION POTENTIAL FOR US LOOKS SLIM WITH THESE SYSTEMS GIVEN THEIR LOCATION...SPEED AND AN OVERALL LACK OF LOW TO MID LEVEL MOISTURE. HOWEVER...THEY WILL BRING A FLUCTUATION IN SURFACE TEMPERATURES OVER THE NEXT FEW DAYS. 850 MB TEMPERATURES ARE FORECAST TO CLIMB 3-5 DEGREES C THURSDAY OVER TODAYS TEMPS DEPENDING ON WHICH MODEL IS VIEWED. GIVEN CURRENT TEMPERATURES IN THE MIDDLE 50S IN THE SNOW-FREE AREAS...LOWER 60S SEEM A GOOD BET FOR TOMORROWS HIGHS. TEMPERATURES WILL COOL TO THE 40S AND 50S FRIDAY AS SURFACE WINDS SHIFT BACK TO NORTHWEST AND 850 TEMPS COOL. THE SNOW COVERED AREAS STILL PRESENT A CHALLENGE FOR TEMPERATURE FORECASTING... REMAINING SOME 15 DEGREES COLDER THAN BARE GROUND. WILL CONTINUE THIS COOLER TREND OVER THE SNOW FOR THE NEXT FEW DAYS BUT WITH DIMINISHING IMPACT AS SNOW COVER DECREASES. THE STRENGTH OF SURFACE WINDS THURSDAY ARE STILL A BIT UNCERTAIN. GUIDANCE DIFFERS WITH FORECAST 850 MB WINDS TOMORROW...WITH THE ECMWF SHOWING SPEEDS OF 15-20 KTS WHILE THE GFS SHOWS 35-40 KTS ACROSS THE NORTH. FOR NOW HAVE PLACED STRONGEST WINDS IN THE NORTH THIRD WITH GUSTS TO AROUND 30 MPH BUT THIS MAY NEED TO BE REVISITED. THE NEXT SIGNIFICANT SYSTEM TO IMPACT THE REGION WILL BE IN THE SATURDAY-SUNDAY TIME FRAME AS A PROGRESSIVE TROUGH DIGS SOUTHEAST FROM THE PACIFIC NORTHWEST. GUIDANCE HAS BEEN HIT AND MISS FOR SPOTTY PRECIPITATION WITH THAT SYSTEM. GIVEN SURFACE HIGH PRESSURE ACROSS THE TX-OK AREA AHEAD OF THIS TROUGH...MOISTURE WILL AGAIN BE SPARSE DOWN LOW. ALTHOUGH SOME SPOTTY PRECIP CANT BE RULED OUT...WILL CONTINUE THE DRY FORECAST. THE LONGER RANGE GUIDANCE INDICATES UPPER RIDGING WILL RETURN EARLY NEXT WEEK...CONTINUING THE MILD AND DRY TREND AS WE KICK OFF THE NEW YEAR. 99 && .AVIATION... 1020 PM MST WED DEC 28 2011 FOR THE 06Z TAFS AT KGLD AND KMCK...VFR THROUGH THE PERIOD. WEST WINDS OF 10-15KTS EXPECTED THROUGH 18Z THEN INCREASING SLIGHTLY WITH GUSTS 25KTS OR SO AS A SFC TROUGH MOVES THROUGH. STILL SOME UNCERTAINTY AS TO WHETHER THE STRONGER WINDS ALOFT MIX DOWN AS LATEST RUC MODEL SHOWING SUSTAINED WINDS AT KGLD AROUND 20-25KTS WITH HIGHER GUSTS BY 20Z. BY 00Z WINDS BACK OFF WITH SPEEDS 10-15KTS. CLOUDINESS WILL BE LIMITED TO MID AND UPPER LEVELS. 007 && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1043 AM EST THU DEC 29 2011 ...Forecast Update... Just some minor updates made to the grids late this morning. AC continues to move overhead, and will gradually move out of the region this afternoon. With the morning clouds giving a slow start to temperature rises, have dropped MaxT just a couple of degrees in the northeast where temperatures are coolest and clouds are most common and will be the most long-lived. BUFKIT has backed off on its wind gust forecasts for this afternoon, but the HRRR keeps us quite gusty and with the sun returning for the afternoon hours, will just knock the wind gust forecast down a couple knots. Gusts to 25 mph still look attainable...maybe even still to 30 mph over southern Indiana and northern Kentucky. Tweaked clouds in the far south and southwest where skies are clearer than farther north. && .Short Term (Today and Tonight)... A couple of low pressure systems will swiftly move across the Great Lakes region throughout the short-term, with the first occurring today, and the second fast on its heels late tonight. These two systems will not only bring increased mid-upper cloudiness to our region today and tonight, but will also increase our winds quite a bit out of the southwest. Because of this, temperatures will moderate some and will likely be at or just over the warmest MOS guidance. After a chilly start to today, expect highs under filtered sunshine to climb into the low-mid 50s, with lows tonight only dropping down to around 40 or the low 40s. With good mixing, expect 15mph sustained winds out of the southwest, with gusts as high as 25-30 at times from late morning through the afternoon hours. The second system approaching late tonight from the northwest will bring light rain to central IL/IN after midnight tonight. This activity should stay north of our CWA through 12z Friday so kept the latter portion of tonight`s forecast dry. .Long Term (Friday - Wednesday)... The models have come into much better agreement with the weather systems for the long term versus this time last night. There will be a couple of chances for precipitation through this period, though neither looks to bring widespread precip to the area. The first system will be Friday as a shortwave tracks across the upper Midwest and into the Great Lakes region. Southern Indiana and north central Kentucky will stand the best chance of seeing any light rain from this system as it quickly tracks eastward Friday. The rain will quickly move off to the east Friday evening, with Saturday remaining dry. For Friday winds will be fairly breezy out of the southwest. Temperatures Friday through Saturday will remain well above normal with highs in the mid 50s and lows in the upper 30s to lower 40s. For Sunday, a strong low pressure system will move out of WI/MN and into southern Canada. This will swing a strong cold front through on Sunday. Most of the moisture associated with this system looks to be closer to the low, so will continue to mention only slight chance to low chance pops. Additionally, models continue to speed up the exit of the precipitation. Think most precip will be out of the area before the cold air has a chance to overspread the region, so have taken out the mention of the rain/snow mix on Sunday night. Much colder air will settle into the Ohio Valley in the wake of this system. Highs on Monday will be only in the low to middle 30s while Tuesday`s highs may not make it out of the 20s in some locations. Lows will be in the lower 20s to teens. Wednesday looks to start a gradual warm up into the latter half of the week. && .Aviation (12Z TAF Issuance)... A couple of disturbances will cross the northern U.S. through this TAF period. Mid level clouds associated with the first system are already streaming across the region. Skies may clear for a bit this evening before more clouds move in overnight. The only concern today will be gusty winds this afternoon. Winds will increase out of the southwest after 15-16Z. Winds will be sustained at 12-15 knots with gusts to 22-25 knots. Gusts will decrease this evening, but winds will remain around 10 knots out of the southwest overnight. The second system crossing the area tomorrow may bring some light rain to SDF. However, with certainty low and little impact expected from the rain, will keep it out of the TAF for now. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...NONE. KY...NONE. $$ Update...........13 Short Term.......AL Long Term........EER Aviation.........AL
AREA FORECAST DISCUSSION
NWS CARIBOU ME
919 PM EST FRI DEC 30 2011 .SYNOPSIS... LOW PRESSURE OVER THE GREAT LAKES WILL WEAKEN TONIGHT WITH REDEVELOPMENT OFF OF CAPE COD ON SATURDAY. THIS NEW LOW PRESSURE WILL TRACK EASTWARD THROUGH THE GULF OF MAINE AND THEN SOUTH OF NOVA SCOTIA BY SATURDAY EVENING. A HIGH PRESSURE RIDGE WILL BUILD ACROSS THE REGION ON SUNDAY.&& .NEAR TERM /THROUGH SATURDAY/... UPDATE 2: INITIAL SURGE OF MOISTURE NOW LIFTING NE ACROSS CENTRAL/E CENTRAL AREAS AND WILL LIFT UP ACROSS NERN AREAS NEXT FEW HRS. HAVE ADJUSTED POPS FOR SOME PSBL LGT -SHSN ACROSS THIS REGION. OTHERWISE...CURRENT FCST REMAINS ON TRACK. UPDATE: INITIAL SURGE OF MOISTURE WEAKENING AS IT SLIDES EWRD ACROSS OUR SRN AREAS AS EXPECTED. FCST APPEARS IN GOOD SHAPE W/ NO ADJUSTMENTS NEEDED ATTM. PREV DISC: SHORTWAVE TROUGH FLATTENING UPPER RIDGE ACROSS THE STATE IS PRODUCING AN AREA OF LIGHT SNOW SHOWERS ACROSS WESTERN MAINE THIS AFTERNOON. HRRR MODEL INDICATES AS THIS SHORTWAVE TROUGH MOVES ACROSS DOWNEAST LATE THIS AFTERNOON INTO THIS EVENING, A PERIOD OF SNOW SHOWERS CAN BE EXPECTED WITH ANY ACCUMULATION LESS THAN AN INCH. MODELS IN GOOD AGREEMENT WITH LOW PRESSURE OVER THE GREAT LAKES FILLING TONIGHT WITH REDEVELOPMENT JUST EAST OF CAPE COD BY SATURDAY AFTERNOON. THE LOW PRESSURE WILL THEN TRACK EASTWARD AND MOVE SOUTH OF NOVA SCOTIA BY SATURDAY NIGHT. WITH HIGH PRESSURE EAST OF THE REGION INSTEAD OF NORTH OF THE STATE, WARM ATLANTIC AIR IN THE LOWER LEVELS WILL BE ALLOWED TO FLOW NORTHWARD ACROSS THE FORECAST AREA PRODUCING ANOTHER WINTRY MIX FOR THE REGION. CRITICAL THICKNESS NOW INDICATING MORE MIX THAN SNOW SO HAVE REDUCE SNOW ACCUMULATION ACROSS CENTRAL AND NORTHERN SECTIONS BY AROUND AN INCH AND INCREASE ICE ACCUMULATIONS BY A TENTH OF AN INCH ACROSS CENTRAL PORTIONS. AT THIS TIME, EXPECT THE AXIS OF HEAVIEST ICE TO OCCUR 30 MILES ON EITHER SIDE OF A LINE FROM GREENVILLE TO HOULTON WHERE UP TO A QUARTER OF AN INCH MAY ACCUMULATE. MODELS ALSO INDICATING TEMPERATURES WILL BE SLOW TO RISE ACROSS DOWNEAST SO WILL EXTEND ADVISORY FROM 7 AM TO NOONTIME SATURDAY.&& .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... THINGS WILL BE WINDING DOWN SATURDAY NIGHT AS THE LOW MOVES OUT OF THE GULF OF MAINE AND SOUTH OF NOVA SCOTIA. THERE WILL BE SOME LINGERING FREEZING RAIN IN NORTHERN SECTIONS DURING THE EVENING BUT COLDER AIR WRAPPING AROUND THE DEPARTING SYSTEM WILL CHANGE THE PRECIPITATION TO ALL SNOW FROM NORTH TO SOUTH THROUGH THE NIGHT. SNOWFALL AMOUNTS WILL BE LIGHT...GENERALLY A DUSTING TO AROUND HALF AN INCH WITH ANOTHER TRACE OF ICE ACCUMULATION. HIGH PRESSURE WILL BRIEFLY BUILD IN SUNDAY BEFORE ANOTHER LOW PRESSURE SYSTEM MOVES BY TO OUR NORTH SUNDAY NIGHT AND MONDAY. THIS WILL BRING ANOTHER ROUND OF SNOW AND RAIN TO THE REGION. THE RAIN/SNOW LINE WILL BE SOUTH OF HOULTON AND MILLINOCKET WITH THE IMMEDIATE COAST ALL RAIN BY MONDAY AFTERNOON. EXPECT TEMPERATURES TO REACH INTO THE 30S DUE TO INCREASING SOUTH FLOW AHEAD OF THE SYSTEM...BUT A STRONG COLD FRONT WILL PUSH THROUGH THE REGION DURING THE DAY MONDAY USHERING IN MUCH COLDER AIR FOR THE WORK WEEK. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... COLDER AIR WILL FILTER INTO THE REGION FOR MONDAY NIGHT AND TUESDAY ACCOMPANIED BY MAINLY CLOUDY SKIES ALONG WITH SCATTERED SNOW SHOWERS AND FLURRIES DUE TO AN UPPER LEVEL TROUGH LINGERING IN THE REGION. PRECIPITATION WILL BE CONFINED MAINLY TO NORTHERN AREAS WHERE A FEW HEAVIER SNOW SHOWERS WILL BE POSSIBLE DUE TO BANDS SETTING UP OFF THE ST. LAWRENCE. HIGH PRESSURE WILL BRIEFLY MOVE IN FOR WEDNESDAY RESULTING IN MAINLY SUNNY SKIES AND DRY CONDITIONS REGION WIDE. HOWEVER TEMPERATURES WILL STRUGGLE TO MAKE IT OUT OF THE LOW TO MID TEENS NORTH WITH HIGHS DOWNEAST REACHING THE LOW 20S. HIGH PRESSURE WILL SLIDE OFF TO THE EAST THURSDAY AS THE NEXT UPPER LEVEL TROUGH APPROACHES THE EAST COAST RESULTING IN INCREASING CLOUDS ALONG WITH THE SLIGHT CHANCE FOR A FEW FLURRIES FOR THE END OF THE WEEK. AT THIS POINT ANY SURFACE CYCLOGENESIS ASSOCIATED WITH THIS TROUGH LOOKS TO TAKE PLACE TOO FAR SOUTH AND EAST TO AFFECT THE REGION WITH SIGNIFICANT PRECIPITATION. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: VFR CONDITIONS TONIGHT WILL LOWER TO IFR IN A WINTRY MIX ON SATURDAY. THERE MAY BE A BRIEF PERIOD OF MVFR/IFR IN SNOW AT KBGR AND KBHB BETWEEN 21Z-02Z AS AN AREA OF SNOW SHOWERS MOVES ACROSS DOWNEAST. SHORT TERM: IFR CONDITIONS IN SNOW AND RAIN THROUGH THE FIRST PART OF SATURDAY NIGHT. PERIODS OF FREEZING RAIN WILL BE POSSIBLE THROUGH 06Z SUNDAY. CONDITIONS WILL GRADUALLY IMPROVE AFTER MIDNIGHT AND EXPECT ALL TERMINALS TO BE VFR BY 12Z SUNDAY. A RETURN TO IFR COMES SUNDAY NIGHT AS SNOW SPREADS OVER THE REGION. IFR IN SNOW AND RAIN SUNDAY NIGHT AND MONDAY. BRIEF PERIODS OF MVFR/IFR CONDITIONS WILL BE POSSIBLE MONDAY NIGHT AND TUESDAY FOR THE NORTHERN SITES DUE TO LINGERING SCATTERED SNOW SHOWERS AND FLURRIES WITH VFR CONDITIONS PREDOMINATING FOR KBGR AND KBHB. HIGH PRESSURE WILL BUILD IN WEDNESDAY WITH VFR CONDITIONS EXPECTED FOR ALL SITES. && .MARINE... NEAR TERM: AS LOW PRESSURE MOVES THROUGH THE GULF OF MAINE, MINIMAL SCA CONDITIONS POSSIBLE OVER OUR OUTER WATERS ON SATURDAY. SHORT TERM: NO HEADLINES ANTICIPATED SATURDAY NIGHT AND SUNDAY AS HIGH PRESSURE BRIEFLY BUILDS OVER THE WATERS. LOW PRESSURE WILL MOVE BY TO THE NORTH SUNDAY NIGHT AND MONDAY SO EXPECT WINDS AND SEAS TO INCREASE THROUGH THE PERIOD. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED WITH GALES A POSSIBILITY. WINDS AND SEAS WILL CONTINUE TO BE AT SCA LEVELS FOR MONDAY NIGHT AND TUESDAY. SEAS WILL DIMINISH WEDNESDAY BUT WINDS WILL CONTINUE TO REMAIN NEAR SCA LEVELS BEFORE DIMINISHING FOR WEDNESDAY NIGHT AND THURSDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY FROM 1 AM TO 7 PM EST SATURDAY FOR MEZ001>006-010. WINTER WEATHER ADVISORY FROM 1 AM TO NOON EST SATURDAY FOR MEZ011-015>017-031-032. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST SATURDAY FOR ANZ050- 051. && $$ NEAR TERM...KHW/FOSTER SHORT TERM...HASTINGS LONG TERM...FITZSIMMONS AVIATION...KHW/FOSTER MARINE...KHW/FOSTER/HASTINGS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
611 PM EST FRI DEC 30 2011 .SYNOPSIS... LOW PRESSURE OVER THE GREAT LAKES WILL WEAKEN TONIGHT WITH REDEVELOPMENT OFF OF CAPE COD ON SATURDAY. THIS NEW LOW PRESSURE WILL TRACK EASTWARD THROUGH THE GULF OF MAINE AND THEN SOUTH OF NOVA SCOTIA BY SATURDAY EVENING. A HIGH PRESSURE RIDGE WILL BUILD ACROSS THE REGION ON SUNDAY.&& .NEAR TERM /THROUGH SATURDAY/... UPDATE: INITIAL SURGE OF MOISTURE WEAKENING AS IT SLIDES EWRD ACROSS OUR SRN AREAS AS EXPECTED. FCST APPEARS IN GOOD SHAPE W/ NO ADJUSTMENTS NEEDED ATTM. PREV DISC: SHORTWAVE TROUGH FLATTENING UPPER RIDGE ACROSS THE STATE IS PRODUCING AN AREA OF LIGHT SNOW SHOWERS ACROSS WESTERN MAINE THIS AFTERNOON. HRRR MODEL INDICATES AS THIS SHORTWAVE TROUGH MOVES ACROSS DOWNEAST LATE THIS AFTERNOON INTO THIS EVENING, A PERIOD OF SNOW SHOWERS CAN BE EXPECTED WITH ANY ACCUMULATION LESS THAN AN INCH. MODELS IN GOOD AGREEMENT WITH LOW PRESSURE OVER THE GREAT LAKES FILLING TONIGHT WITH REDEVELOPMENT JUST EAST OF CAPE COD BY SATURDAY AFTERNOON. THE LOW PRESSURE WILL THEN TRACK EASTWARD AND MOVE SOUTH OF NOVA SCOTIA BY SATURDAY NIGHT. WITH HIGH PRESSURE EAST OF THE REGION INSTEAD OF NORTH OF THE STATE, WARM ATLANTIC AIR IN THE LOWER LEVELS WILL BE ALLOWED TO FLOW NORTHWARD ACROSS THE FORECAST AREA PRODUCING ANOTHER WINTRY MIX FOR THE REGION. CRITICAL THICKNESS NOW INDICATING MORE MIX THAN SNOW SO HAVE REDUCE SNOW ACCUMULATION ACROSS CENTRAL AND NORTHERN SECTIONS BY AROUND AN INCH AND INCREASE ICE ACCUMULATIONS BY A TENTH OF AN INCH ACROSS CENTRAL PORTIONS. AT THIS TIME, EXPECT THE AXIS OF HEAVIEST ICE TO OCCUR 30 MILES ON EITHER SIDE OF A LINE FROM GREENVILLE TO HOULTON WHERE UP TO A QUARTER OF AN INCH MAY ACCUMULATE. MODELS ALSO INDICATING TEMPERATURES WILL BE SLOW TO RISE ACROSS DOWNEAST SO WILL EXTEND ADVISORY FROM 7 AM TO NOONTIME SATURDAY. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... THINGS WILL BE WINDING DOWN SATURDAY NIGHT AS THE LOW MOVES OUT OF THE GULF OF MAINE AND SOUTH OF NOVA SCOTIA. THERE WILL BE SOME LINGERING FREEZING RAIN IN NORTHERN SECTIONS DURING THE EVENING BUT COLDER AIR WRAPPING AROUND THE DEPARTING SYSTEM WILL CHANGE THE PRECIPITATION TO ALL SNOW FROM NORTH TO SOUTH THROUGH THE NIGHT. SNOWFALL AMOUNTS WILL BE LIGHT...GENERALLY A DUSTING TO AROUND HALF AN INCH WITH ANOTHER TRACE OF ICE ACCUMULATION. HIGH PRESSURE WILL BRIEFLY BUILD IN SUNDAY BEFORE ANOTHER LOW PRESSURE SYSTEM MOVES BY TO OUR NORTH SUNDAY NIGHT AND MONDAY. THIS WILL BRING ANOTHER ROUND OF SNOW AND RAIN TO THE REGION. THE RAIN/SNOW LINE WILL BE SOUTH OF HOULTON AND MILLINOCKET WITH THE IMMEDIATE COAST ALL RAIN BY MONDAY AFTERNOON. EXPECT TEMPERATURES TO REACH INTO THE 30S DUE TO INCREASING SOUTH FLOW AHEAD OF THE SYSTEM...BUT A STRONG COLD FRONT WILL PUSH THROUGH THE REGION DURING THE DAY MONDAY USHERING IN MUCH COLDER AIR FOR THE WORK WEEK. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... COLDER AIR WILL FILTER INTO THE REGION FOR MONDAY NIGHT AND TUESDAY ACCOMPANIED BY MAINLY CLOUDY SKIES ALONG WITH SCATTERED SNOW SHOWERS AND FLURRIES DUE TO AN UPPER LEVEL TROUGH LINGERING IN THE REGION. PRECIPITATION WILL BE CONFINED MAINLY TO NORTHERN AREAS WHERE A FEW HEAVIER SNOW SHOWERS WILL BE POSSIBLE DUE TO BANDS SETTING UP OFF THE ST. LAWRENCE. HIGH PRESSURE WILL BRIEFLY MOVE IN FOR WEDNESDAY RESULTING IN MAINLY SUNNY SKIES AND DRY CONDITIONS REGION WIDE. HOWEVER TEMPERATURES WILL STRUGGLE TO MAKE IT OUT OF THE LOW TO MID TEENS NORTH WITH HIGHS DOWNEAST REACHING THE LOW 20S. HIGH PRESSURE WILL SLIDE OFF TO THE EAST THURSDAY AS THE NEXT UPPER LEVEL TROUGH APPROACHES THE EAST COAST RESULTING IN INCREASING CLOUDS ALONG WITH THE SLIGHT CHANCE FOR A FEW FLURRIES FOR THE END OF THE WEEK. AT THIS POINT ANY SURFACE CYCLOGENESIS ASSOCIATED WITH THIS TROUGH LOOKS TO TAKE PLACE TOO FAR SOUTH AND EAST TO AFFECT THE REGION WITH SIGNIFICANT PRECIPITATION. && .AVIATION /23Z FRIDAY THROUGH WEDNESDAY/... NEAR TERM: VFR CONDITIONS TONIGHT WILL LOWER TO IFR IN A WINTRY MIX ON SATURDAY. THERE MAY BE A BRIEF PERIOD OF MVFR/IFR IN SNOW AT KBGR AND KBHB BETWEEN 21Z-02Z AS AN AREA OF SNOW SHOWERS MOVES ACROSS DOWNEAST. SHORT TERM: IFR CONDITIONS IN SNOW AND RAIN THROUGH THE FIRST PART OF SATURDAY NIGHT. PERIODS OF FREEZING RAIN WILL BE POSSIBLE THROUGH 06Z SUNDAY. CONDITIONS WILL GRADUALLY IMPROVE AFTER MIDNIGHT AND EXPECT ALL TERMINALS TO BE VFR BY 12Z SUNDAY. A RETURN TO IFR COMES SUNDAY NIGHT AS SNOW SPREADS OVER THE REGION. IFR IN SNOW AND RAIN SUNDAY NIGHT AND MONDAY. BRIEF PERIODS OF MVFR/IFR CONDITIONS WILL BE POSSIBLE MONDAY NIGHT AND TUESDAY FOR THE NORTHERN SITES DUE TO LINGERING SCATTERED SNOW SHOWERS AND FLURRIES WITH VFR CONDITIONS PREDOMINATING FOR KBGR AND KBHB. HIGH PRESSURE WILL BUILD IN WEDNESDAY WITH VFR CONDITIONS EXPECTED FOR ALL SITES. && .MARINE... NEAR TERM: AS LOW PRESSURE MOVES THROUGH THE GULF OF MAINE, MINIMAL SCA CONDITIONS POSSIBLE OVER OUR OUTER WATERS ON SATURDAY. SHORT TERM: NO HEADLINES ANTICIPATED SATURDAY NIGHT AND SUNDAY AS HIGH PRESSURE BRIEFLY BUILDS OVER THE WATERS. LOW PRESSURE WILL MOVE BY TO THE NORTH SUNDAY NIGHT AND MONDAY SO EXPECT WINDS AND SEAS TO INCREASE THROUGH THE PERIOD. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED WITH GALES A POSSIBILITY. WINDS AND SEAS WILL CONTINUE TO BE AT SCA LEVELS FOR MONDAY NIGHT AND TUESDAY. SEAS WILL DIMINISH WEDNESDAY BUT WINDS WILL CONTINUE TO REMAIN NEAR SCA LEVELS BEFORE DIMINISHING FOR WEDNESDAY NIGHT AND THURSDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY FROM 1 AM TO 7 PM EST SATURDAY FOR MEZ001>006-010. WINTER WEATHER ADVISORY FROM 1 AM TO NOON EST SATURDAY FOR MEZ011-015>017-031-032. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST SATURDAY FOR ANZ050- 051. && $$ NEAR TERM...KHW/FOSTER SHORT TERM...HASTINGS LONG TERM...FITZSIMMONS AVIATION...KHW/FOSTER MARINE...KHW/FOSTER/HASTINGS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1039 PM EST FRI DEC 30 2011 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OFF TO THE SOUTHEAST TONIGHT AS A COLD FRONT APPROACHES FROM THE WEST. THE FRONT PASSES THROUGH SATURDAY MORNING...WITH HIGH PRESSURE BUILDING IN FOR THE REMAINDER OF THE DAY AND NIGHT. A MUCH STRONGER COLD FRONT CROSSES THE REGION BY SUNDAY NIGHT...WITH AN ARCTIC AIRMASS OVERSPREADING THE MID ATLANTIC FOR THE UPCOMING WORK WEEK. && .NEAR TERM /THROUGH SATURDAY/... CHANCES FOR PRECIP OVERNIGHT LOOKING MORE AND MORE LIMITED. UPSTREAM RADAR OVER KY AND TN STILL SHOWS A LACK OF DEVELOPMENT AND THE TREND WITH THE RUC HAS BEEN TO REDUCE THE COVERAGE OF PRECIP OVERNIGHT. STILL THINK THERE WILL BE A PERIOD OF BRIEF SCATTERED AND PATCHY LIGHT RAIN BUT SOME AREAS ESPECIALLY WEST OF RIC MAY NOT SEE ANY PRECIP AT ALL. THOSE AREAS FROM RIC EAST WHICH MIGHT SEE A FEW SHOWERS WILL ONLY EXPERIENCE A BRIEF SHOWER. WILL KEEP VERY LOW CHANCE POPS IN THE FORECAST BUT FOR ANY GIVEN AREA THE CHANCE FOR PRECIP WILL BE NO MORE THAN JUST A FEW HOURS FROM 06Z-12Z. DESPITE A LACK OF DEEP MOISTURE THE DYNAMICS WILL BE STRONG ENOUGH TO SQUEEZE OUT A FEW SHOWERS. IR SATELLITE SHOWS CONTINUED ENHANCEMENT IN THE CLOUD TOPS NORTH AND WEST OF THE CWA. THE WRF NMM AND ARW ARE BOTH LESS EXCITED ABOUT PRECIPITATION OVERNIGHT BUT STILL BRING A FEW BRIEF WIDELY SCATTERED SHOWERS ACROSS THE AREA. WITH THIS IN MIND WILL KEEP THE SMALL CHANCE POPS (25-30%). OVERALL PRECIP IN ANY GIVEN LOCATION WILL NOT LAST VERY LONG AND COVERAGE COULD BE RATHER LIMITED. RAINFALL WILL LIKELY JUST BE ENOUGH TO WET THE GROUND BUT LESS THAN A TENTH OF AN INCH ON AVERAGE. SOME RAIN MAY LINGER PAST 12Z OVER EXTREME SE VA/NE NC AND THE EASTERN SHORE. PRECIP WILL SHUT OFF QUICKLY FOLLOWING THE PASSAGE OF THE MID-LEVEL TROUGH AXIS. TEMPS THIS EVENING WILL BE TEMPERED BY INCREASING CLOUDS FROM THE WEST. LOWS WILL STABILIZE IN THE IN THE UPR 40S ON AVERAGE BUT WITH DEWPOINTS IN THE MID TO UPPER 30S SOME EVAP COOLING IN AREAS OF SHOWERS COULD PUSH SOME LOCAL READINGS INTO THE MID 40S. FOR SATURDAY MIXING IN THE WESTERLY FLOW BEHIND THE DEPARTING TROUGH AXIS WILL WARM TEMPS INTO THE UPPER 50S TO MID 60S UNDER MOSTLY SUNNY SKIES. WINDS WILL PICK UP SOME BY LATE MORNING RESULTING IN WEST WINDS AROUND 10 TO 15 MPH WITH A FEW GUSTS TO NEAR 20 MPH. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... CLR OR MSTLY CLR SAT NGT WITH LIGHT WINDS ALLOWING TEMPS TO FALL INTO THE MID TO UPR 30S. WARM AGAIN ON SUN AHEAD OF AN APPROACHING STRONG COLD FRONT. WITH DEEP SW FLOW...EXPECT HIGHS IN THE LWR TO MID 60S OVR MOST OF THE AREA. THE COLD FROPA OCCURS SUN AFTN/EVNG...BUT WILL MAINTAIN A DRY FORECAST DUE TO A LACK OF MOISTURE (POPS CAPPED AT 14%). SKY COVER MAY NOT BE GREATER THAN PRTLY CLDY. ARTIC AIRMASS BEGINS OVERSPREADING THE MID ATLANTIC EARLY IN THE WORK WEEK BEHIND THE COLD FRONT AS A POLAR VORTEX DROPS INTO SE CANADA. TEMPS ON MON WILL ONLY MAX OUT IN THE LOW TO MID 40S...WITH WIND CHILLS IN THE MID 30S. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... FIRST ARCTIC AIRMASS OF THE SEASON COMES IN MONDAY NIGHT AND CONTINUES THROUGH WEDNESDAY. TIGHTENING PRES GRADIENT ALONG WITH WEAK S/W ENERGY WILL MAKE TUESDAY A COLD / BLUSTERY DAY WITH TEMPS HARD PRESSED TO GET MUCH ABOVE THE L-M30S ALONG WITH GUSTY NW WINDS OF 25-35 MPH. WIND CHILLS BETWEEN 15-25 DEGREES. GIVEN PROGGED H85 TMPS OF ARND -15C COMBINED WITH WATER TEMPS ARND 9C TUES...I WAS SOMEWHAT CONCERNED ABOUT THE PSBLTY OF BAY EFFECT SNOW SHOWERS DVLPNG. HOWEVER...WINDS WILL BE MORE NW THAN DUE N ALONG WITH DP TEMPS BETWEEN 0-5 ABOVE W OF BAY...ARND 10 NEAR THE WATER. EXPECT MORE BAY EFFECT STREAMER SC CLOUDS THAN PCPN. STILL CAN`T RULE OUT A FLURRY OR TWO ALONG THE COAST TUE AS MOISTURE FIELDS BEGIN TO EXPAND IN RESPONSE TO DVLPNG COASTAL LOW. 12Z EURO MORE ROBUST AND CLOSER TO THE COAST WITH SAID COASTAL LOW THAN GFS. AT MOST...SOME FLURRIES OR SNOW SHWRS CUD ROTATE W TOWARD COASTAL AREAS TUE NIGHT...BUT CONFIDENCE NOT HIGH ENUF ATTM TO LEAN IN THAT DIRECTION. INSTEAD...EXPECT WINDS TO SLOWLY DIMINISH TUE NITE ALONG WITH PT CLDY SKIES. TEMPS DROP INTO THE TEENS MOST AREAS...NR 20 ALONG THE SE COAST. RIDGE AXIS STILL WEST OF FA WED SO IT WILL CONT DRY / COLD BUT WITH LESS WIND. HIGHS IN THE M-U30S. LOWS WED NITE L-M20S. WITH A DOMINATE NORTHERN JET STREAM AND NO DOWNSTREAM BLOCKING... NEXT S/W CLIPPER PROGGED TO TRACK NORTH OF FA THU. MAY SEE SOME CLOUDS WITH THIS FEATURE BUT NO PRECIP ATTM. SLOW WARMING TREND AS WINDS SHIFT INTO THE SW. HIGHS THU L-M40S AND M-U40S FRI. LOWS THU NITE IN THE M20S-L30S. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... AN AREA OF LOW PRESSURE WILL PASS TO THE NORTH OF THE FORECAST AREA ON SAT. AN ASSOCIATED COLD FRONT WILL PASS THROUGH THE AREA FROM THE WEST SAT MORNING. EXPECT CEILINGS TO LOWER OVERNIGHT TO AROUND 4-5K FT THROUGH OUT THE AREA. A BRIEF PERIOD PERIOD OF -RA AND OVC030 CEILINGS WILL IMPACT KRIC AND KSBY BEFORE PASSING OFF THE COAST. 5-10KT S/SW WINDS WILL PREVAIL BEFORE FRONTAL PASSAGE WITH WEST WINDS GUSTING TO AROUND 20KT MIXING DOWN AFTER PASSAGE. HIGH PRESSURE BUILDS IN BRIEFLY FROM THE SOUTH LATE SAT AND SUN BEFORE ANOTHER COLD FRONT/WIND SHIFT APPROACHES THE AREA SUN NIGHT. && .MARINE... TRICKY FORECAST TONIGHT/SAT AS SHORT RANGE MODELS HINT THAT S-SW WINDS WILL APPROACH MINIMAL SCA LEVELS OVER THE CHES BAY. WILL FORECAST A SOLID 15 KTS WITH THIS PACKAGE WITH GUSTS AROUND 20 KT. OTW...SW-W FLOW CONTINUES THROUGH THE WKEND...AS HIGH PRESSURE MOVES OFF THE COAST. NEXT CHC FOR SCA CONDITIONS COMES SUNDAY NIGHT AND MONDAY AS A COLD FRONT PROGGED TO MOVE OFF THE COAST. BEYOND THAT...OFFSHORE LOW DEEPENS MONDAY NIGHT AND TUESDAY BEFORE LIFTING NE AND AWAY FROM REGION BY MID WEEK. LATEST DATA SUPPORTS A DEEP MIXING LAYER AS ARCTIC AIRMASS PRODUCES STRONG CAA ACROSS ENTIRE MARINE AREA. AT THIS POINT...CONFIDENCE IS GROWING FOR GALE FORCE WINDS / GUSTS MONDAY NIGHT AND TUESDAY. STAY TUNED. && .CLIMATE... VERY WARM DECEMBER TO END A VERY WARM YEAR FOR 2011: BASED ON PREDICTED TEMPERATURES FOR THE REST OF THE MONTH: RICHMOND...WILL LIKELY END UP AS 8TH WARMEST DECEMBER ON RECORD...AND THE 4TH WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 7TH COLDEST AND ABOUT 13 F COLDER THAN THIS DEC! NORFOLK...WILL LIKELY END UP AS THE 6TH OR 7TH WARMEST DECEMBER ON RECORD...AND 3RD WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 4TH COLDEST AND ABOUT 15 F COLDER THAN THIS DEC! MORE DETAILS AS WE END THE YR. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR ANZ630>632- 634. && $$ SYNOPSIS...MAS NEAR TERM...JAO SHORT TERM...MAS LONG TERM...DAP/MPR AVIATION...DAP MARINE...MPR CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1000 PM EST FRI DEC 30 2011 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OFF TO THE SOUTHEAST TONIGHT AS A COLD FRONT APPROACHES FROM THE WEST. THE FRONT PASSES THROUGH SATURDAY MORNING...WITH HIGH PRESSURE BUILDING IN FOR THE REMAINDER OF THE DAY AND NIGHT. A MUCH STRONGER COLD FRONT CROSSES THE REGION BY SUNDAY NIGHT...WITH AN ARCTIC AIRMASS OVERSPREADING THE MID ATLANTIC FOR THE UPCOMING WORK WEEK. && .NEAR TERM /THROUGH SATURDAY/... CHANCES FOR PRECIP OVERNIGHT LOOKING MORE AND MORE LIMITED. UPSTREAM RADAR OVER KY AND TN STILL SHOWS A LACK OF DEVELOPMENT AND THE TREND WITH THE RUC HAS BEEN TO REDUCE THE COVERAGE OF PRECIP OVERNIGHT. STILL THINK THERE WILL BE A PERIOD OF BRIEF SCATTERED AND PATCHY LIGHT RAIN BUT SOME AREAS ESPECIALLY WEST OF RIC MAY NOT SEE ANY PRECIP AT ALL. THOSE AREAS FROM RIC EAST WHICH MIGHT SEE A FEW SHOWERS WILL ONLY EXPERIENCE A BRIEF SHOWER. WILL KEEP VERY LOW CHANCE POPS IN THE FORECAST BUT FOR ANY GIVEN AREA THE CHANCE FOR PRECIP WILL BE NO MORE THAN JUST A FEW HOURS FROM 06Z-12Z. DESPITE A LACK OF DEEP MOISTURE THE DYNAMICS WILL BE STRONG ENOUGH TO SQUEEZE OUT A FEW SHOWERS. IR SATELLITE SHOWS CONTINUED ENHANCEMENT IN THE CLOUD TOPS NORTH AND WEST OF THE CWA. THE WRF NMM AND ARW ARE BOTH LESS EXCITED ABOUT PRECIPITATION OVERNIGHT BUT STILL BRING A FEW BRIEF WIDELY SCATTERED SHOWERS ACROSS THE AREA. WITH THIS IN MIND WILL KEEP THE SMALL CHANCE POPS (25-30%). OVERALL PRECIP IN ANY GIVEN LOCATION WILL NOT LAST VERY LONG AND COVERAGE COULD BE RATHER LIMITED. RAINFALL WILL LIKELY JUST BE ENOUGH TO WET THE GROUND BUT LESS THAN A TENTH OF AN INCH ON AVERAGE. SOME RAIN MAY LINGER PAST 12Z OVER EXTREME SE VA/NE NC AND THE EASTERN SHORE. PRECIP WILL SHUT OFF QUICKLY FOLLOWING THE PASSAGE OF THE MID-LEVEL TROUGH AXIS. TEMPS THIS EVENING WILL BE TEMPERED BY INCREASING CLOUDS FROM THE WEST. LOWS WILL STABILIZE IN THE IN THE UPR 40S ON AVERAGE BUT WITH DEWPOINTS IN THE MID TO UPPER 30S SOME EVAP COOLING IN AREAS OF SHOWERS COULD PUSH SOME LOCAL READINGS INTO THE MID 40S. FOR SATURDAY MIXING IN THE WESTERLY FLOW BEHIND THE DEPARTING TROUGH AXIS WILL WARM TEMPS INTO THE UPPER 50S TO MID 60S UNDER MOSTLY SUNNY SKIES. WINDS WILL PICK UP SOME BY LATE MORNING RESULTING IN WEST WINDS AROUND 10 TO 15 MPH WITH A FEW GUSTS TO NEAR 20 MPH. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... CLR OR MSTLY CLR SAT NGT WITH LIGHT WINDS ALLOWING TEMPS TO FALL INTO THE MID TO UPR 30S. WARM AGAIN ON SUN AHEAD OF AN APPROACHING STRONG COLD FRONT. WITH DEEP SW FLOW...EXPECT HIGHS IN THE LWR TO MID 60S OVR MOST OF THE AREA. THE COLD FROPA OCCURS SUN AFTN/EVNG...BUT WILL MAINTAIN A DRY FORECAST DUE TO A LACK OF MOISTURE (POPS CAPPED AT 14%). SKY COVER MAY NOT BE GREATER THAN PRTLY CLDY. ARTIC AIRMASS BEGINS OVERSPREADING THE MID ATLANTIC EARLY IN THE WORK WEEK BEHIND THE COLD FRONT AS A POLAR VORTEX DROPS INTO SE CANADA. TEMPS ON MON WILL ONLY MAX OUT IN THE LOW TO MID 40S...WITH WIND CHILLS IN THE MID 30S. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... FIRST ARCTIC AIRMASS OF THE SEASON COMES IN MONDAY NIGHT AND CONTINUES THROUGH WEDNESDAY. TIGHTENING PRES GRADIENT ALONG WITH WEAK S/W ENERGY WILL MAKE TUESDAY A COLD / BLUSTERY DAY WITH TEMPS HARD PRESSED TO GET MUCH ABOVE THE L-M30S ALONG WITH GUSTY NW WINDS OF 25-35 MPH. WIND CHILLS BETWEEN 15-25 DEGREES. GIVEN PROGGED H85 TMPS OF ARND -15C COMBINED WITH WATER TEMPS ARND 9C TUES...I WAS SOMEWHAT CONCERNED ABOUT THE PSBLTY OF BAY EFFECT SNOW SHOWERS DVLPNG. HOWEVER...WINDS WILL BE MORE NW THAN DUE N ALONG WITH DP TEMPS BETWEEN 0-5 ABOVE W OF BAY...ARND 10 NEAR THE WATER. EXPECT MORE BAY EFFECT STREAMER SC CLOUDS THAN PCPN. STILL CAN`T RULE OUT A FLURRY OR TWO ALONG THE COAST TUE AS MOISTURE FIELDS BEGIN TO EXPAND IN RESPONSE TO DVLPNG COASTAL LOW. 12Z EURO MORE ROBUST AND CLOSER TO THE COAST WITH SAID COASTAL LOW THAN GFS. AT MOST...SOME FLURRIES OR SNOW SHWRS CUD ROTATE W TOWARD COASTAL AREAS TUE NIGHT...BUT CONFIDENCE NOT HIGH ENUF ATTM TO LEAN IN THAT DIRECTION. INSTEAD...EXPECT WINDS TO SLOWLY DIMINISH TUE NITE ALONG WITH PT CLDY SKIES. TEMPS DROP INTO THE TEENS MOST AREAS...NR 20 ALONG THE SE COAST. RIDGE AXIS STILL WEST OF FA WED SO IT WILL CONT DRY / COLD BUT WITH LESS WIND. HIGHS IN THE M-U30S. LOWS WED NITE L-M20S. WITH A DOMINATE NORTHERN JET STREAM AND NO DOWNSTREAM BLOCKING... NEXT S/W CLIPPER PROGGED TO TRACK NORTH OF FA THU. MAY SEE SOME CLOUDS WITH THIS FEATURE BUT NO PRECIP ATTM. SLOW WARMING TREND AS WINDS SHIFT INTO THE SW. HIGHS THU L-M40S AND M-U40S FRI. LOWS THU NITE IN THE M20S-L30S. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... AN AREA OF LOW PRESSURE WILL PASS TO THE NORTH OF THE FORECAST AREA ON SAT. AN ASSOCIATED COLD FRONT WILL PASS THROUGH THE AREA FROM THE WEST SAT MORNING. EXPECT CEILINGS TO LOWER OVERNIGHT TO AROUND 4-5K FT THROUGH OUT THE AREA. A BRIEF PERIOD PERIOD OF -RA AND OVC030 CEILINGS WILL IMPACT KRIC AND KSBY BEFORE PASSING OFF THE COAST. 5-10KT S/SW WINDS WILL PREVAIL BEFORE FRONTAL PASSAGE WITH WEST WINDS GUSTING TO AROUND 20KT MIXING DOWN AFTER PASSAGE. HIGH PRESSURE BUILDS IN BRIEFLY FROM THE SOUTH LATE SAT AND SUN BEFORE ANOTHER COLD FRONT/WIND SHIFT APPROACHES THE AREA SUN NIGHT. && .MARINE... TRICKY FORECAST TONIGHT/SAT AS SHORT RANGE MODELS HINT THAT S-SW WINDS COULD APPROACH MINIMAL SCA LEVELS OVER THE CHES BAY. SINCE CONFIDENCE NOT THERE FOR ANY EXTENDED PERIOD OF WINDS AT 20 KTS...WILL FORECAST A SOLID 15 KTS WITH THIS PACKAGE. OTW...SW-W FLOW CONTINUES THROUGH THE WKEND...AS HIGH PRESSURE MOVES OFF THE COAST. NEXT CHC FOR SCA CONDITIONS COMES SUNDAY NIGHT AND MONDAY AS A COLD FRONT PROGGED TO MOVE OFF THE COAST. BEYOND THAT...OFFSHORE LOW DEEPENS MONDAY NIGHT AND TUESDAY BEFORE LIFTING NE AND AWAY FROM REGION BY MID WEEK. LATEST DATA SUPPORTS A DEEP MIXING LAYER AS ARCTIC AIRMASS PRODUCES STRONG CAA ACROSS ENTIRE MARINE AREA. AT THIS POINT...CONFIDENCE IS GROWING FOR GALE FORCE WINDS / GUSTS MONDAY NIGHT AND TUESDAY. STAY TUNED. && .CLIMATE... VERY WARM DECEMBER TO END A VERY WARM YEAR FOR 2011: BASED ON PREDICTED TEMPERATURES FOR THE REST OF THE MONTH: RICHMOND...WILL LIKELY END UP AS 8TH WARMEST DECEMBER ON RECORD...AND THE 4TH WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 7TH COLDEST AND ABOUT 13 F COLDER THAN THIS DEC! NORFOLK...WILL LIKELY END UP AS THE 6TH OR 7TH WARMEST DECEMBER ON RECORD...AND 3RD WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 4TH COLDEST AND ABOUT 15 F COLDER THAN THIS DEC! MORE DETAILS AS WE END THE YR. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAS NEAR TERM...JAO SHORT TERM...MAS LONG TERM...MPR AVIATION...DAP MARINE...MPR CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
812 PM EST FRI DEC 30 2011 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OFF TO THE SOUTHEAST TONIGHT AS A COLD FRONT APPROACHES FROM THE WEST. THE FRONT PASSES THROUGH SATURDAY MORNING...WITH HIGH PRESSURE BUILDING IN FOR THE REMAINDER OF THE DAY AND NIGHT. A MUCH STRONGER COLD FRONT CROSSES THE REGION BY SUNDAY NIGHT...WITH AN ARCTIC AIRMASS OVERSPREADING THE MID ATLANTIC FOR THE UPCOMING WORK WEEK. && .NEAR TERM /THROUGH SATURDAY/... MAIN FORECAST CHALLENGE THIS EVENING IS THE SMALL CHANCE POPS LATE TONIGHT TOWARDS SATURDAY MORNING. THE PRIMARY FORCING IS ASSOCIATED WITH THE APPROACHING UPPER TROUGH COMING ACROSS KENTUCKY AND TENNESSEE THIS EVENING. THE GFS...NAM AND RUC ALL BRING A PERIOD OF LIFT (OMEGA) RAPIDLY ACROSS THE CWA FROM 05Z-13Z. DESPITE DEEP MOISTURE MODELS SUGGEST THE DYNAMICS WILL BE STRONG ENOUGH TO SQUEEZE OUT A FEW SCATTERED SHOWERS. THE PRIMARY CONCERN WITH THESE MODELS AS OF 00Z THEY SUGGEST THERE SHOULD BE SOME LIGHT PRECIP OVER NORTHERN ALABAMA AND MIDDLE TENNESSEE WHICH IS NOT THERE. IR SATELLITE SHOWS SOME ENHANCEMENT IN THE CLOUD TOPS OVER UPSTATE GA AND EAST TENNESSEE. THIS SUGGEST THE WRF NMM AND ARW MAY BE ONTO SOMETHING BOTH OF WHICH ARE LESS EXCITED ABOUT PRECIPITATION OVERNIGHT BUT STILL BRING WIDELY SCATTERED ACROSS THE AREA. WITH THIS IN MIND WILL KEEP THE SMALL CHANCE POPS (25-30%) IN THE FORECAST TRENDING THE POPS UP AND DOWN RAPIDLY FROM WEST TO EAST FROM 05Z-13Z. OVERALL PRECIP IN ANY GIVEN LOCATION SHOULD NOT LAST VERY LONG AND COVERAGE SHOULD BE RATHER SCATTERED AT BEST. QPF WILL LIKELY JUST BE ENOUGH TO WET THE GROUND BUT LESS THAN A TENTH OF AN INCH ON AVERAGE. SOME RAIN MAY LINGER PAST 12Z OVER EXTREME SE VA/NE NC AND THE EASTERN SHORE. PRECIP WILL SHUT OFF QUICKLY FOLLOWING THE PASSAGE OF THE MID-LEVEL TROUGH AXIS. TEMPS THIS EVENING WILL BE TEMPERED BY INCREASING CLOUDS FROM THE WEST. LOWS WILL STABILIZE IN THE IN THE UPR 40S ON AVERAGE BUT WITH DEWPOINTS IN THE MID TO UPPER 30S SOME EVAP COOLING IN AREAS OF SHOWERS COULD PUSH SOME LOCAL READINGS INTO THE MID 40S. FOR SATURDAY MIXING IN THE WESTERLY FLOW BEHIND THE DEPARTING TROUGH AXIS WILL WARM TEMPS INTO THE UPPER 50S TO MID 60S UNDER MOSTLY SUNNY SKIES. WINDS WILL PICK UP SOME BY LATE MORNING RESULTING IN WEST WINDS AROUND 10 TO 15 MPH WITH A FEW GUSTS TO NEAR 20 MPH. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... CLR OR MSTLY CLR SAT NGT WITH LIGHT WINDS ALLOWING TEMPS TO FALL INTO THE MID TO UPR 30S. WARM AGAIN ON SUN AHEAD OF AN APPROACHING STRONG COLD FRONT. WITH DEEP SW FLOW...EXPECT HIGHS IN THE LWR TO MID 60S OVR MOST OF THE AREA. THE COLD FROPA OCCURS SUN AFTN/EVNG...BUT WILL MAINTAIN A DRY FORECAST DUE TO A LACK OF MOISTURE (POPS CAPPED AT 14%). SKY COVER MAY NOT BE GREATER THAN PRTLY CLDY. ARTIC AIRMASS BEGINS OVERSPREADING THE MID ATLANTIC EARLY IN THE WORK WEEK BEHIND THE COLD FRONT AS A POLAR VORTEX DROPS INTO SE CANADA. TEMPS ON MON WILL ONLY MAX OUT IN THE LOW TO MID 40S...WITH WIND CHILLS IN THE MID 30S. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... FIRST ARCTIC AIRMASS OF THE SEASON COMES IN MONDAY NIGHT AND CONTINUES THROUGH WEDNESDAY. TIGHTENING PRES GRADIENT ALONG WITH WEAK S/W ENERGY WILL MAKE TUESDAY A COLD / BLUSTERY DAY WITH TEMPS HARD PRESSED TO GET MUCH ABOVE THE L-M30S ALONG WITH GUSTY NW WINDS OF 25-35 MPH. WIND CHILLS BETWEEN 15-25 DEGREES. GIVEN PROGGED H85 TMPS OF ARND -15C COMBINED WITH WATER TEMPS ARND 9C TUES...I WAS SOMEWHAT CONCERNED ABOUT THE PSBLTY OF BAY EFFECT SNOW SHOWERS DVLPNG. HOWEVER...WINDS WILL BE MORE NW THAN DUE N ALONG WITH DP TEMPS BETWEEN 0-5 ABOVE W OF BAY...ARND 10 NEAR THE WATER. EXPECT MORE BAY EFFECT STREAMER SC CLOUDS THAN PCPN. STILL CAN`T RULE OUT A FLURRY OR TWO ALONG THE COAST TUE AS MOISTURE FIELDS BEGIN TO EXPAND IN RESPONSE TO DVLPNG COASTAL LOW. 12Z EURO MORE ROBUST AND CLOSER TO THE COAST WITH SAID COASTAL LOW THAN GFS. AT MOST...SOME FLURRIES OR SNOW SHWRS CUD ROTATE W TOWARD COASTAL AREAS TUE NIGHT...BUT CONFIDENCE NOT HIGH ENUF ATTM TO LEAN IN THAT DIRECTION. INSTEAD...EXPECT WINDS TO SLOWLY DIMINISH TUE NITE ALONG WITH PT CLDY SKIES. TEMPS DROP INTO THE TEENS MOST AREAS...NR 20 ALONG THE SE COAST. RIDGE AXIS STILL WEST OF FA WED SO IT WILL CONT DRY / COLD BUT WITH LESS WIND. HIGHS IN THE M-U30S. LOWS WED NITE L-M20S. WITH A DOMINATE NORTHERN JET STREAM AND NO DOWNSTREAM BLOCKING... NEXT S/W CLIPPER PROGGED TO TRACK NORTH OF FA THU. MAY SEE SOME CLOUDS WITH THIS FEATURE BUT NO PRECIP ATTM. SLOW WARMING TREND AS WINDS SHIFT INTO THE SW. HIGHS THU L-M40S AND M-U40S FRI. LOWS THU NITE IN THE M20S-L30S. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... AN AREA OF LOW PRESSURE WILL PASS TO THE NORTH OF THE FORECAST AREA ON SAT. AN ASSOCIATED COLD FRONT WILL PASS THROUGH THE AREA FROM THE WEST SAT MORNING. EXPECT CEILINGS TO LOWER OVERNIGHT TO AROUND 4-5K FT THROUGH OUT THE AREA. A BRIEF PERIOD PERIOD OF -RA AND OVC030 CEILINGS WILL IMPACT KRIC AND KSBY BEFORE PASSING OFF THE COAST. 5-10KT S/SW WINDS WILL PREVAIL BEFORE FRONTAL PASSAGE WITH WEST WINDS GUSTING TO AROUND 20KT MIXING DOWN AFTER PASSAGE. HIGH PRESSURE BUILDS IN BRIEFLY FROM THE SOUTH LATE SAT AND SUN BEFORE ANOTHER COLD FRONT/WIND SHIFT APPROACHES THE AREA SUN NIGHT. && .MARINE... TRICKY FORECAST TONIGHT/SAT AS SHORT RANGE MODELS HINT THAT S-SW WINDS COULD APPROACH MINIMAL SCA LEVELS OVER THE CHES BAY. SINCE CONFIDENCE NOT THERE FOR ANY EXTENDED PERIOD OF WINDS AT 20 KTS...WILL FORECAST A SOLID 15 KTS WITH THIS PACKAGE. OTW...SW-W FLOW CONTINUES THROUGH THE WKEND...AS HIGH PRESSURE MOVES OFF THE COAST. NEXT CHC FOR SCA CONDITIONS COMES SUNDAY NIGHT AND MONDAY AS A COLD FRONT PROGGED TO MOVE OFF THE COAST. BEYOND THAT...OFFSHORE LOW DEEPENS MONDAY NIGHT AND TUESDAY BEFORE LIFTING NE AND AWAY FROM REGION BY MID WEEK. LATEST DATA SUPPORTS A DEEP MIXING LAYER AS ARCTIC AIRMASS PRODUCES STRONG CAA ACROSS ENTIRE MARINE AREA. AT THIS POINT...CONFIDENCE IS GROWING FOR GALE FORCE WINDS / GUSTS MONDAY NIGHT AND TUESDAY. STAY TUNED. && .CLIMATE... VERY WARM DECEMBER TO END A VERY WARM YEAR FOR 2011: BASED ON PREDICTED TEMPERATURES FOR THE REST OF THE MONTH: RICHMOND...WILL LIKELY END UP AS 8TH WARMEST DECEMBER ON RECORD...AND THE 4TH WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 7TH COLDEST AND ABOUT 13 F COLDER THAN THIS DEC! NORFOLK...WILL LIKELY END UP AS THE 6TH OR 7TH WARMEST DECEMBER ON RECORD...AND 3RD WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 4TH COLDEST AND ABOUT 15 F COLDER THAN THIS DEC! MORE DETAILS AS WE END THE YR. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAS NEAR TERM...JAO SHORT TERM...MAS LONG TERM...MPR AVIATION...DAP MARINE...MPR CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
803 PM EST FRI DEC 30 2011 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OFF TO THE SOUTHEAST TONIGHT AS A COLD FRONT APPROACHES FROM THE WEST. THE FRONT PASSES THROUGH SATURDAY MORNING...WITH HIGH PRESSURE BUILDING IN FOR THE REMAINDER OF THE DAY AND NIGHT. A MUCH STRONGER COLD FRONT CROSSES THE REGION BY SUNDAY NIGHT...WITH AN ARCTIC AIRMASS OVERSPREADING THE MID ATLANTIC FOR THE UPCOMING WORK WEEK. && .NEAR TERM /THROUGH SATURDAY/... MAIN FORECAST CHALLENGE THIS EVENING IS THE SMALL CHANCE POPS LATE TONIGHT TOWARDS SATURDAY MORNING. THE PRIMARY FORCING IS ASSOCIATED WITH THE APPROACHING UPPER TROUGH COMING ACROSS KENTUCKY AND TENNESSEE THIS EVENING. THE GFS...NAM AND RUC ALL BRING A PERIOD OF LIFT (OMEGA) RAPIDLY ACROSS THE CWA FROM 05Z-13Z. DESPITE DEEP MOISTURE MODELS SUGGEST THE DYNAMICS WILL BE STRONG ENOUGH TO SQUEEZE OUT A FEW SCATTERED SHOWERS. THE PRIMARY CONCERN WITH THESE MODELS AS OF 00Z THEY SUGGEST THERE SHOULD BE SOME LIGHT PRECIP OVER NORTHERN ALABAMA AND MIDDLE TENNESSEE WHICH IS NOT THERE. IR SATELLITE SHOWS SOME ENHANCEMENT IN THE CLOUD TOPS OVER UPSTATE GA AND EAST TENNESSEE. THIS SUGGEST THE WRF NMM AND ARW MAY BE ONTO SOMETHING BOTH OF WHICH ARE LESS EXCITED ABOUT PRECIPITATION OVERNIGHT BUT STILL BRING WIDELY SCATTERED ACROSS THE AREA. WITH THIS IN MIND WILL KEEP THE SMALL CHANCE POPS (25-30%) IN THE FORECAST TRENDING THE POPS UP AND DOWN RAPIDLY FROM WEST TO EAST FROM 05Z-13Z. OVERALL PRECIP IN ANY GIVEN LOCATION SHOULD NOT LAST VERY LONG AND COVERAGE SHOULD BE RATHER SCATTERED AT BEST. QPF WILL LIKELY JUST BE ENOUGH TO WET THE GROUND BUT LESS THAN A TENTH OF AN INCH ON AVERAGE. SOME RAIN MAY LINGER PAST 12Z OVER EXTREME SE VA/NE NC AND THE EASTERN SHORE. PRECIP WILL SHUT OFF QUICKLY FOLLOWING THE PASSAGE OF THE MID-LEVEL TROUGH AXIS. TEMPS THIS EVENING WILL BE TEMPERED BY INCREASING CLOUDS FROM THE WEST. LOWS WILL STABILIZE IN THE IN THE UPR 40S ON AVERAGE BUT WITH DEWPOINTS IN THE MID TO UPPER 30S SOME EVAP COOLING IN AREAS OF SHOWERS COULD PUSH SOME LOCAL READINGS INTO THE MID 40S. FOR SATURDAY MIXING IN THE WESTERLY FLOW BEHIND THE DEPARTING TROUGH AXIS WILL WARM TEMPS INTO THE UPPER 50S TO MID 60S UNDER MOSTLY SUNNY SKIES. WINDS WILL PICK UP SOME BY LATE MORNING RESULTING IN WEST WINDS AROUND 10 TO 15 MPH WITH A FEW GUSTS TO NEAR 20 MPH. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... CLR OR MSTLY CLR SAT NGT WITH LIGHT WINDS ALLOWING TEMPS TO FALL INTO THE MID TO UPR 30S. WARM AGAIN ON SUN AHEAD OF AN APPROACHING STRONG COLD FRONT. WITH DEEP SW FLOW...EXPECT HIGHS IN THE LWR TO MID 60S OVR MOST OF THE AREA. THE COLD FROPA OCCURS SUN AFTN/EVNG...BUT WILL MAINTAIN A DRY FORECAST DUE TO A LACK OF MOISTURE (POPS CAPPED AT 14%). SKY COVER MAY NOT BE GREATER THAN PRTLY CLDY. ARTIC AIRMASS BEGINS OVERSPREADING THE MID ATLANTIC EARLY IN THE WORK WEEK BEHIND THE COLD FRONT AS A POLAR VORTEX DROPS INTO SE CANADA. TEMPS ON MON WILL ONLY MAX OUT IN THE LOW TO MID 40S...WITH WIND CHILLS IN THE MID 30S. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... FIRST ARCTIC AIRMASS OF THE SEASON COMES IN MONDAY NIGHT AND CONTINUES THROUGH WEDNESDAY. TIGHTENING PRES GRADIENT ALONG WITH WEAK S/W ENERGY WILL MAKE TUESDAY A COLD / BLUSTERY DAY WITH TEMPS HARD PRESSED TO GET MUCH ABOVE THE L-M30S ALONG WITH GUSTY NW WINDS OF 25-35 MPH. WIND CHILLS BETWEEN 15-25 DEGREES. GIVEN PROGGED H85 TMPS OF ARND -15C COMBINED WITH WATER TEMPS ARND 9C TUES...I WAS SOMEWHAT CONCERNED ABOUT THE PSBLTY OF BAY EFFECT SNOW SHOWERS DVLPNG. HOWEVER...WINDS WILL BE MORE NW THAN DUE N ALONG WITH DP TEMPS BETWEEN 0-5 ABOVE W OF BAY...ARND 10 NEAR THE WATER. EXPECT MORE BAY EFFECT STREAMER SC CLOUDS THAN PCPN. STILL CAN`T RULE OUT A FLURRY OR TWO ALONG THE COAST TUE AS MOISTURE FIELDS BEGIN TO EXPAND IN RESPONSE TO DVLPNG COASTAL LOW. 12Z EURO MORE ROBUST AND CLOSER TO THE COAST WITH SAID COASTAL LOW THAN GFS. AT MOST...SOME FLURRIES OR SNOW SHWRS CUD ROTATE W TOWARD COASTAL AREAS TUE NIGHT...BUT CONFIDENCE NOT HIGH ENUF ATTM TO LEAN IN THAT DIRECTION. INSTEAD...EXPECT WINDS TO SLOWLY DIMINISH TUE NITE ALONG WITH PT CLDY SKIES. TEMPS DROP INTO THE TEENS MOST AREAS...NR 20 ALONG THE SE COAST. RIDGE AXIS STILL WEST OF FA WED SO IT WILL CONT DRY / COLD BUT WITH LESS WIND. HIGHS IN THE M-U30S. LOWS WED NITE L-M20S. WITH A DOMINATE NORTHERN JET STREAM AND NO DOWNSTREAM BLOCKING... NEXT S/W CLIPPER PROGGED TO TRACK NORTH OF FA THU. MAY SEE SOME CLOUDS WITH THIS FEATURE BUT NO PRECIP ATTM. SLOW WARMING TREND AS WINDS SHIFT INTO THE SW. HIGHS THU L-M40S AND M-U40S FRI. LOWS THU NITE IN THE M20S-L30S. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS EXPECTED THROUGH FORECAST PERIOD. MID/HIGH LEVEL CLOUDS ASSCTD WITH FIRST S/W NOW MOVG EAST LEAVING ONLY SCT CLOUDS ACROSS THE REGION THIS AFTERNOON ALONG WITH A S-SW WIND AOB 10 KTS. CLOUD DECK AROUND 5K FT ASSCTD WITH NEXT S/W OVERSPREADS REGION LATE THIS EVE AND THROUGH OVERNIGHT PERIOD. MODELS DIFFER ON HOW MUCH MOISTURE ACCOMPANIES THIS SYSTEM. TIMING AND LOCATIONS FOR ANY LIGHT RAIN WILL BE BETWEEN 10-14Z MAINLY N OF RIC TO SBY. SBY MAY SEE A FEW HOUR PERIOD OF MVFR CONDITIONS AROUND 12Z. WINDS SHIFT INTO THE W (10-15KTS) BEHIND DEPARTING S/W ENERGY SAT ALONG WITH DECREASING CLOUDS. MUCH COLDER AIR IS EXPECTED TO SURGE INTO THE REGION EARLY NEXT WEEK PRODUCING A STRONG GUSTY W TO NW WIND MONDAY AND TUESDAY. && .MARINE... TRICKY FORECAST TONIGHT/SAT AS SHORT RANGE MODELS HINT THAT S-SW WINDS COULD APPROACH MINIMAL SCA LEVELS OVER THE CHES BAY. SINCE CONFIDENCE NOT THERE FOR ANY EXTENDED PERIOD OF WINDS AT 20 KTS...WILL FORECAST A SOLID 15 KTS WITH THIS PACKAGE. OTW...SW-W FLOW CONTINUES THROUGH THE WKEND...AS HIGH PRESSURE MOVES OFF THE COAST. NEXT CHC FOR SCA CONDITIONS COMES SUNDAY NIGHT AND MONDAY AS A COLD FRONT PROGGED TO MOVE OFF THE COAST. BEYOND THAT...OFFSHORE LOW DEEPENS MONDAY NIGHT AND TUESDAY BEFORE LIFTING NE AND AWAY FROM REGION BY MID WEEK. LATEST DATA SUPPORTS A DEEP MIXING LAYER AS ARCTIC AIRMASS PRODUCES STRONG CAA ACROSS ENTIRE MARINE AREA. AT THIS POINT...CONFIDENCE IS GROWING FOR GALE FORCE WINDS / GUSTS MONDAY NIGHT AND TUESDAY. STAY TUNED. && .CLIMATE... VERY WARM DECEMBER TO END A VERY WARM YEAR FOR 2011: BASED ON PREDICTED TEMPERATURES FOR THE REST OF THE MONTH: RICHMOND...WILL LIKELY END UP AS 8TH WARMEST DECEMBER ON RECORD...AND THE 4TH WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 7TH COLDEST AND ABOUT 13 F COLDER THAN THIS DEC! NORFOLK...WILL LIKELY END UP AS THE 6TH OR 7TH WARMEST DECEMBER ON RECORD...AND 3RD WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 4TH COLDEST AND ABOUT 15 F COLDER THAN THIS DEC! MORE DETAILS AS WE END THE YR. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAS NEAR TERM...JAO SHORT TERM...MAS LONG TERM...MPR AVIATION...MPR MARINE...MPR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1244 PM EST THU DEC 29 2011 UPDATED AVIATION DISCUSSION FOR 18Z TAFS .UPDATE... LIGHT SNOW HAS SPREAD ACROSS THE AREA NORTH OF SFC LOW OVER SOUTHERN WI. SNOW HAS BEEN HEAVIER OVER SOUTH CENTRAL UPPER MICHIGAN AND ALSO OVER LK SUPERIOR OVR KEWEENAW PENINSULA. SO FAR...HIGHEST AMOUNTS WITH THE SYSTEM HAVE BEEN LESS THAN AN INCH. SE BLYR WINDS OFF LK MICHIGAN WILL CONTRIBUTE TO INCREASING LAKE ENHANCED SNOW FOR DELTA COUNTY AND SCHOOLCRAFT COUNTY THIS AFTN. NOT ALL THAT COLD AT H85 BUT INVERSION TOP TEMPS ARE SLIGHTLY COLDER...AROUND -8C...LEADING TO DELTA T/S AROUND 13C. SCNTRL UPR MI IS ALSO WHERE RUC INDICATES PERIOD OF H85 THETA-E ADVECTION TO ENHANCE THE SNOW. OPTED TO INCLUDE DELTA COUNTY IN SNOW ADVY FOR AFTN. TOTAL SNOW AMOUNTS WILL BE A STRETCH TO REACH 4 INCHES FOR THE AFTN...BUT TOTALS IN THE 2 TO 4 INCH RANGE WITH LOWER VSBY...DOWN TO 1/2SM IN HEAVIER SNOW...SEEMS TO JUSTIFY PUTTING DELTA INTO THE ADVY. EXPECT HEAVIER SNOW TO CEASE BY LATE AFTN OR EARLY EVENING AS BETTER THETA-E ADVECTION DIMINISHES TO THE EAST AS MAIN SHORTWAVE MOVES OUT OF THE AREA. OTHER SPOT TO WATCH WILL BE KEWEENAW AS SIMILAR SETUP IS PRESENT. SHEAR IN LOWEST 2KFT IS MORE NOTED WITH ESE WINDS AT SFC AND MORE SRLY WINDS TOWARD 925MB PER MQT VWP. HIGHER TERRAIN OF KEWEENAW COUNTY IS ORIENTED MORE WEST-TO-EAST SO WITH THE SOUTHERLY WINDS IN LOW-LEVELS THERE IS MORE OF AN UPSLOPE COMPONENT THERE COMPARED TO HOUGHTON COUNTY. COUNTY SHERIFF REPORTS A COUPLE INCHES THUS FAR OVR HIGHER TERRAIN. SINCE HEAVIER SNOW MAY LAST A FEW HOURS LONGER BASED ON STRONGER H85 THETA-E ADVECTION...WILL PUT ADVY UP FOR KEWEENAW COUNTY FOR THE AFTN. && .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A STRONG WRLY MID/UPPER LEVEL FLOW INTO THE PAC NW AND WNW FLOW DOWNSTREAM FROM THE SRN CANADA AND NRN PLAINS INTO THE GREAT LAKES. ONE SHEARED SHORTWAVE TROUGH WAS LOCATED NORTH OF LAKE SUPERIOR AND ANOTHER WAS MOVING THROUGH SW MN. AT THE SFC...A 997 MB LOW WAS LOCATED OVER SRN MN RESULTING IN S TO SE WINDS ACROSS UPPER MICHIGAN. AN AREA OF SNOW FROM NE MN INTO WRN LAKE SUPERIOR NW WI WITH VSBYS INTO THE 1-3SM RANGE WAS SUPPORTED BY 285K-290K ASCENT AHEAD OF A 850-700 MB TROUGH. ANY LAKE EFFECT/ENHANCED SNOW OFF OF LAKE MICHIGAN WITH THE SRLY FLOW HAS BEEN MINIMAL WITH ONLY A DUSTING AT MOST. && .DISCUSSION... TODAY AND TONIGHT...EXPECT THE AREA OF SNOW TO PROGRESS ACROSS UPPER MICHIGAN TODAY. MODELS CONSENSUS QPF OF AROUND A TENTH OF AN INCH WITH SNOW/WATER RATIO VALUES NEAR 15/1 WOULD RESULT IN SNOWFALL AMOUNTS OF AN INCH OR TWO WHICH IS REASONABLE GIVEN 2G-3G/KG MOISTURE AVBL NEAR 700MB DURING A 6 HOUR PERIOD OF STRONGER LIFT. UNCERTAINTY REMAINS WITH REGARD TO LAKE ENHANCED SNOW POTENTIAL INTO THE SE CWA. THE HIGHER RES MODELS HAVE BEEN OVERDOING PCPN WITH BANDS OFF OF LAKE MICHIGAN SO FAR. HOWEVER...AS THE DEEPER MOISTURE ARRIVES...EXPECT THAT THE LAKE CONTRIBUTION MAY ADD AN ADDITIONAL 1-2 INCHES TO SNOWFALL AMOUNTS. SINCE THE WINDS WERE BACKING MORE SERLY AHEAD OF THE LOW...THE BEST LOW LEVEL CONV AND OVER WATER TRAJECTORIES HAVE SHIFTED TO THE WEST. SO...HAVE CANCELLED THE ADVY FOR LUCE COUNTY AND CONTINUED MENTION OF 2 TO 4 INCHES OF SNOW IN THE ADVY FOR SCHOOLCRAFT COUNTY TODAY. MODELS SUGGEST THAT THE DEEPER MOISTURE WILL QUICKLY DEPART THIS AFTERNOON OVER THE WEST. HOWEVER...LACK OF LOW LEVEL LIFT OR FOCUSING MECHANISM SHOULD MINIMIZE POTENTIAL FOR -FZDZ. SOME LIGHT SNOW WILL LINGER OVER THE ERN CWA TONIGHT AS THE SFC-850 MB TROUGH SLOWLY PIVOTS TO THE NORTHEAST. FRIDAY...MODELS WERE IN AGREEMENT THAT THE PCPN ASSOCIATED WITH A SHORTWAVE MOVING FROM THE PAC THROUGH THE NRN PLAINS INTO THE MS VALLEY AND SRN GREAT LAKES IS EXPECTED TO REMAIN SOUTH OF UPPER MI. SOME ISOLATED LIGHT SNOW SHOWERS MAY BE POSSIBLE NEAR AN INVERTED TROUGH AXIS INTO THE NRN CWA. AGAIN...-FZDZ MAY ALSO BE POSSIBLE BUT PROBABILITIES REMAIN LOW. SAT INTO SUN...THE NEXT MID LEVEL TROUGH IN THE PROGRESSIVE PATTERN WILL MOVE INTO THE REGION BY LATE SAT. WAA AHEAD OF THE MID LEVEL AND SFC TROUGH MAY BRING SOME LIGHT PCPN INTO THE WRN CWA. THE MORE CONSISTENT ECMWF WAS PREFERRED FOR DETAILS WITH THE SYSTEM AS THE GFS AND NAM HAVE AT TIMES SHOWED A STRONGER SHORTWAVE SWEEPING THROUGH THE REGION THAT WOULD GENERATE SUBSTANTIAL PCPN AND BRING MUCH GREATER DEEPENING OF THE SFC LOW. FALLING TEMPS AND BLUSTERY WNW WINDS ARE EXPECTED BY SUN AFTERNOON BEHIND A STRONG COLD FRONT. SUN NIGHT INTO TUE...AS THE PATTERN BRIEFLY AMPLIFIES...MUCH COLDER AIR WILL POUR INTO THE WRN LAKES ON NW TO N WINDS DROPPING 850 MB TEMPS TO AROUND -20C. SUBTLE MODEL DIFFERENCES REMAIN WITH THE PREVAILING WIND DIRECTION AS THE GFS REMAINS MORE TO THE NW COMPARED TO THE NRLY DIRECTION DEPICTED BY THE ECMWF/GEM. SIGNIFICANT LES REMAINS POSSIBLE WITH INTENSITY DROPPING OFF MON AS DEEPER MOISTURE DEPARTS. && .AVIATION /FOR THE 18Z TAF ISSUANCE/... A LOW PRESSURE SYSTEM MOVING S OF THE AREA EARLY AFTN WILL BRING -SN AND IFR CONDITIONS TO KCMX/KSAW. LIGHT SNOW HAS ALREADY DIMINISHED AT KIWD. EVEN ONCE THE SNOW ENDS...COULD BE DIFFICULT TO GET RID OF THE LOWER CIGS GIVEN LIGHT LOW-LEVEL WINDS AND THUS WEAK ADVECTION OF ANY DRIER AIR AT THE LOW-LEVELS. EXPECT IFR CIGS TO POSSIBLY LINGER ALL NIGHT AT KCMX WITH WINDS COMING OFF OF LK SUPERIOR. EXPECT IMPROVEMENT AT KIWD/KSAW TO AT LEAST MVFR. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... A LOW PRESSURE SYSTEM OVER MN WILL MOVE EAST TODAY. ALTHOUGH WINDS SHOULD STAY BELOW GALE FORCE...THEY WILL BECOME RATHER GUSTY OUT OF THE SOUTHEAST WITH PERHAPS A GUST OR TWO CLOSE TO GALE FORCE. AFTER ANOTHER LOW MOVES ACROSS THE LOWER LAKES ON FRIDAY...A WEAK RIDGE BUILDS ACROSS LAKE SUPERIOR INTO SATURDAY BEFORE A STRONG LOW DEVELOPS OVER THE PLAINS AND MOVES NORTH OF LAKE SUPERIOR FOR NEW YEARS DAY. HIGH END NORTH-NORTHWEST GALES ARE POSSIBLE WITH THIS SYSTEM INTO MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ013- 014-085. WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ001. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SYNOPSIS...JLB DISCUSSION...JLB AVIATION...JLA MARINE...TITUS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1133 AM EST THU DEC 29 2011 .UPDATE... LIGHT SNOW HAS SPREAD ACROSS THE AREA NORTH OF SFC LOW OVER SOUTHERN WI. SNOW HAS BEEN HEAVIER OVER SOUTH CENTRAL UPPER MICHIGAN AND ALSO OVER LK SUPERIOR OVR KEWEENAW PENINSULA. SO FAR...HIGHEST AMOUNTS WITH THE SYSTEM HAVE BEEN LESS THAN AN INCH. SE BLYR WINDS OFF LK MICHIGAN WILL CONTRIBUTE TO INCREASING LAKE ENHANCED SNOW FOR DELTA COUNTY AND SCHOOLCRAFT COUNTY THIS AFTN. NOT ALL THAT COLD AT H85 BUT INVERSION TOP TEMPS ARE SLIGHTLY COLDER...AROUND -8C...LEADING TO DELTA T/S AROUND 13C. SCNTRL UPR MI IS ALSO WHERE RUC INDICATES PERIOD OF H85 THETA-E ADVECTION TO ENHANCE THE SNOW. OPTED TO INCLUDE DELTA COUNTY IN SNOW ADVY FOR AFTN. TOTAL SNOW AMOUNTS WILL BE A STRETCH TO REACH 4 INCHES FOR THE AFTN...BUT TOTALS IN THE 2 TO 4 INCH RANGE WITH LOWER VSBY...DOWN TO 1/2SM IN HEAVIER SNOW...SEEMS TO JUSTIFY PUTTING DELTA INTO THE ADVY. EXPECT HEAVIER SNOW TO CEASE BY LATE AFTN OR EARLY EVENING AS BETTER THETA-E ADVECTION DIMINISHES TO THE EAST AS MAIN SHORTWAVE MOVES OUT OF THE AREA. OTHER SPOT TO WATCH WILL BE KEWEENAW AS SIMILAR SETUP IS PRESENT. SHEAR IN LOWEST 2KFT IS MORE NOTED WITH ESE WINDS AT SFC AND MORE SRLY WINDS TOWARD 925MB PER MQT VWP. HIGHER TERRAIN OF KEWEENAW COUNTY IS ORIENTED MORE WEST-TO-EAST SO WITH THE SOUTHERLY WINDS IN LOW-LEVELS THERE IS MORE OF AN UPSLOPE COMPONENT THERE COMPARED TO HOUGHTON COUNTY. COUNTY SHERIFF REPORTS A COUPLE INCHES THUS FAR OVR HIGHER TERRAIN. SINCE HEAVIER SNOW MAY LAST A FEW HOURS LONGER BASED ON STRONGER H85 THETA-E ADVECTION...WILL PUT ADVY UP FOR KEWEENAW COUNTY FOR THE AFTN. && PREV DISCUSSION...ISSUED AT 631 AM EST THU DEC 29 2011... .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A STRONG WRLY MID/UPPER LEVEL FLOW INTO THE PAC NW AND WNW FLOW DOWNSTREAM FROM THE SRN CANADA AND NRN PLAINS INTO THE GREAT LAKES. ONE SHEARED SHORTWAVE TROUGH WAS LOCATED NORTH OF LAKE SUPERIOR AND ANOTHER WAS MOVING THROUGH SW MN. AT THE SFC...A 997 MB LOW WAS LOCATED OVER SRN MN RESULTING IN S TO SE WINDS ACROSS UPPER MICHIGAN. AN AREA OF SNOW FROM NE MN INTO WRN LAKE SUPERIOR NW WI WITH VSBYS INTO THE 1-3SM RANGE WAS SUPPORTED BY 285K-290K ASCENT AHEAD OF A 850-700 MB TROUGH. ANY LAKE EFFECT/ENHANCED SNOW OFF OF LAKE MICHIGAN WITH THE SRLY FLOW HAS BEEN MINIMAL WITH ONLY A DUSTING AT MOST. && .DISCUSSION... TODAY AND TONIGHT...EXPECT THE AREA OF SNOW TO PROGRESS ACROSS UPPER MICHIGAN TODAY. MODELS CONSENSUS QPF OF AROUND A TENTH OF AN INCH WITH SNOW/WATER RATIO VALUES NEAR 15/1 WOULD RESULT IN SNOWFALL AMOUNTS OF AN INCH OR TWO WHICH IS REASONABLE GIVEN 2G-3G/KG MOISTURE AVBL NEAR 700MB DURING A 6 HOUR PERIOD OF STRONGER LIFT. UNCERTAINTY REMAINS WITH REGARD TO LAKE ENHANCED SNOW POTENTIAL INTO THE SE CWA. THE HIGHER RES MODELS HAVE BEEN OVERDOING PCPN WITH BANDS OFF OF LAKE MICHIGAN SO FAR. HOWEVER...AS THE DEEPER MOISTURE ARRIVES...EXPECT THAT THE LAKE CONTRIBUTION MAY ADD AN ADDITIONAL 1-2 INCHES TO SNOWFALL AMOUNTS. SINCE THE WINDS WERE BACKING MORE SERLY AHEAD OF THE LOW...THE BEST LOW LEVEL CONV AND OVER WATER TRAJECTORIES HAVE SHIFTED TO THE WEST. SO...HAVE CANCELLED THE ADVY FOR LUCE COUNTY AND CONTINUED MENTION OF 2 TO 4 INCHES OF SNOW IN THE ADVY FOR SCHOOLCRAFT COUNTY TODAY. MODELS SUGGEST THAT THE DEEPER MOISTURE WILL QUICKLY DEPART THIS AFTERNOON OVER THE WEST. HOWEVER...LACK OF LOW LEVEL LIFT OR FOCUSING MECHANISM SHOULD MINIMIZE POTENTIAL FOR -FZDZ. SOME LIGHT SNOW WILL LINGER OVER THE ERN CWA TONIGHT AS THE SFC-850 MB TROUGH SLOWLY PIVOTS TO THE NORTHEAST. FRIDAY...MODELS WERE IN AGREEMENT THAT THE PCPN ASSOCIATED WITH A SHORTWAVE MOVING FROM THE PAC THROUGH THE NRN PLAINS INTO THE MS VALLEY AND SRN GREAT LAKES IS EXPECTED TO REMAIN SOUTH OF UPPER MI. SOME ISOLATED LIGHT SNOW SHOWERS MAY BE POSSIBLE NEAR AN INVERTED TROUGH AXIS INTO THE NRN CWA. AGAIN...-FZDZ MAY ALSO BE POSSIBLE BUT PROBABILITIES REMAIN LOW. SAT INTO SUN...THE NEXT MID LEVEL TROUGH IN THE PROGRESSIVE PATTERN WILL MOVE INTO THE REGION BY LATE SAT. WAA AHEAD OF THE MID LEVEL AND SFC TROUGH MAY BRING SOME LIGHT PCPN INTO THE WRN CWA. THE MORE CONSISTENT ECMWF WAS PREFERRED FOR DETAILS WITH THE SYSTEM AS THE GFS AND NAM HAVE AT TIMES SHOWED A STRONGER SHORTWAVE SWEEPING THROUGH THE REGION THAT WOULD GENERATE SUBSTANTIAL PCPN AND BRING MUCH GREATER DEEPENING OF THE SFC LOW. FALLING TEMPS AND BLUSTERY WNW WINDS ARE EXPECTED BY SUN AFTERNOON BEHIND A STRONG COLD FRONT. SUN NIGHT INTO TUE...AS THE PATTERN BRIEFLY AMPLIFIES...MUCH COLDER AIR WILL POUR INTO THE WRN LAKES ON NW TO N WINDS DROPPING 850 MB TEMPS TO AROUND -20C. SUBTLE MODEL DIFFERENCES REMAIN WITH THE PREVAILING WIND DIRECTION AS THE GFS REMAINS MORE TO THE NW COMPARED TO THE NRLY DIRECTION DEPICTED BY THE ECMWF/GEM. SIGNIFICANT LES REMAINS POSSIBLE WITH INTENSITY DROPPING OFF MON AS DEEPER MOISTURE DEPARTS. && .AVIATION /FOR THE 12Z TAF ISSUANCE/... A LOW PRESSURE SYSTEM MOVING S OF THE AREA TODAY WILL BRING -SN TO ALL TAF SITES...RESULTING IN IFR CONDITIONS. LIFR CONDITIONS ARE POSSIBLE AS WELL...ESPECIALLY AT KCMX...DURING PERIOD OF HEAVIEST SNOW. IMPROVEMENT EXPECTED W TO E LATE MORNING/AFTN AS MAIN AREA OF -SN EXITS. HOWEVER...IT MAY BE DIFFICULT TO GET RID OF THE LOWER CIGS GIVEN LIGHT LOW-LEVEL WINDS AND THUS WEAK ADVECTION OF ANY DRIER AIR AT THE LOW-LEVELS. SO...CIGS MAY REMAIN IFR OR ONLY RISE SLIGHTLY TO LOW MVFR IN THE AFTN. IWD IS THE MOST LIKELY TO SEE SIGNIFICANT IMPROVEMENT. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... A LOW PRESSURE SYSTEM OVER MN WILL MOVE EAST TODAY. ALTHOUGH WINDS SHOULD STAY BELOW GALE FORCE...THEY WILL BECOME RATHER GUSTY OUT OF THE SOUTHEAST WITH PERHAPS A GUST OR TWO CLOSE TO GALE FORCE. AFTER ANOTHER LOW MOVES ACROSS THE LOWER LAKES ON FRIDAY...A WEAK RIDGE BUILDS ACROSS LAKE SUPERIOR INTO SATURDAY BEFORE A STRONG LOW DEVELOPS OVER THE PLAINS AND MOVES NORTH OF LAKE SUPERIOR FOR NEW YEARS DAY. HIGH END NORTH-NORTHWEST GALES ARE POSSIBLE WITH THIS SYSTEM INTO MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ013- 014-085. WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ001. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SYNOPSIS...JLB DISCUSSION...JLB AVIATION...TITUS MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
631 AM EST THU DEC 29 2011 UPDATED AVIATION DISCUSSION FOR 12Z TAFS .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A STRONG WRLY MID/UPPER LEVEL FLOW INTO THE PAC NW AND WNW FLOW DOWNSTREAM FROM THE SRN CANADA AND NRN PLAINS INTO THE GREAT LAKES. ONE SHEARED SHORTWAVE TROUGH WAS LOCATED NORTH OF LAKE SUPERIOR AND ANOTHER WAS MOVING THROUGH SW MN. AT THE SFC...A 997 MB LOW WAS LOCATED OVER SRN MN RESULTING IN S TO SE WINDS ACROSS UPPER MICHIGAN. AN AREA OF SNOW FROM NE MN INTO WRN LAKE SUPERIOR NW WI WITH VSBYS INTO THE 1-3SM RANGE WAS SUPPORTED BY 285K-290K ASCENT AHEAD OF A 850-700 MB TROUGH. ANY LAKE EFFECT/ENHANCED SNOW OFF OF LAKE MICHIGAN WITH THE SRLY FLOW HAS BEEN MINIMAL WITH ONLY A DUSTING AT MOST. && .DISCUSSION... TODAY AND TONIGHT...EXPECT THE AREA OF SNOW TO PROGRESS ACROSS UPPER MICHIGAN TODAY. MODELS CONSENSUS QPF OF AROUND A TENTH OF AN INCH WITH SNOW/WATER RATIO VALUES NEAR 15/1 WOULD RESULT IN SNOWFALL AMOUNTS OF AN INCH OR TWO WHICH IS REASONABLE GIVEN 2G-3G/KG MOISTURE AVBL NEAR 700MB DURING A 6 HOUR PERIOD OF STRONGER LIFT. UNCERTAINTY REMAINS WITH REGARD TO LAKE ENHANCED SNOW POTENTIAL INTO THE SE CWA. THE HIGHER RES MODELS HAVE BEEN OVERDOING PCPN WITH BANDS OFF OF LAKE MICHIGAN SO FAR. HOWEVER...AS THE DEEPER MOISTURE ARRIVES...EXPECT THAT THE LAKE CONTRIBUTION MAY ADD AN ADDITIONAL 1-2 INCHES TO SNOWFALL AMOUNTS. SINCE THE WINDS WERE BACKING MORE SERLY AHEAD OF THE LOW...THE BEST LOW LEVEL CONV AND OVER WATER TRAJECTORIES HAVE SHIFTED TO THE WEST. SO...HAVE CANCELLED THE ADVY FOR LUCE COUNTY AND CONTINUED MENTION OF 2 TO 4 INCHES OF SNOW IN THE ADVY FOR SCHOOLCRAFT COUNTY TODAY. MODELS SUGGEST THAT THE DEEPER MOISTURE WILL QUICKLY DEPART THIS AFTERNOON OVER THE WEST. HOWEVER...LACK OF LOW LEVEL LIFT OR FOCUSING MECHANISM SHOULD MINIMIZE POTENTIAL FOR -FZDZ. SOME LIGHT SNOW WILL LINGER OVER THE ERN CWA TONIGHT AS THE SFC-850 MB TROUGH SLOWLY PIVOTS TO THE NORTHEAST. FRIDAY...MODELS WERE IN AGREEMENT THAT THE PCPN ASSOCIATED WITH A SHORTWAVE MOVING FROM THE PAC THROUGH THE NRN PLAINS INTO THE MS VALLEY AND SRN GREAT LAKES IS EXPECTED TO REMAIN SOUTH OF UPPER MI. SOME ISOLATED LIGHT SNOW SHOWERS MAY BE POSSIBLE NEAR AN INVERTED TROUGH AXIS INTO THE NRN CWA. AGAIN...-FZDZ MAY ALSO BE POSSIBLE BUT PROBABILITIES REMAIN LOW. SAT INTO SUN...THE NEXT MID LEVEL TROUGH IN THE PROGRESSIVE PATTERN WILL MOVE INTO THE REGION BY LATE SAT. WAA AHEAD OF THE MID LEVEL AND SFC TROUGH MAY BRING SOME LIGHT PCPN INTO THE WRN CWA. THE MORE CONSISTENT ECMWF WAS PREFERRED FOR DETAILS WITH THE SYSTEM AS THE GFS AND NAM HAVE AT TIMES SHOWED A STRONGER SHORTWAVE SWEEPING THROUGH THE REGION THAT WOULD GENERATE SUBSTANTIAL PCPN AND BRING MUCH GREATER DEEPENING OF THE SFC LOW. FALLING TEMPS AND BLUSTERY WNW WINDS ARE EXPECTED BY SUN AFTERNOON BEHIND A STRONG COLD FRONT. SUN NIGHT INTO TUE...AS THE PATTERN BRIEFLY AMPLIFIES...MUCH COLDER AIR WILL POUR INTO THE WRN LAKES ON NW TO N WINDS DROPPING 850 MB TEMPS TO AROUND -20C. SUBTLE MODEL DIFFERENCES REMAIN WITH THE PREVAILING WIND DIRECTION AS THE GFS REMAINS MORE TO THE NW COMPARED TO THE NRLY DIRECTION DEPICTED BY THE ECMWF/GEM. SIGNIFICANT LES REMAINS POSSIBLE WITH INTENSITY DROPPING OFF MON AS DEEPER MOISTURE DEPARTS. && .AVIATION /FOR THE 12Z TAF ISSUANCE/... A LOW PRESSURE SYSTEM MOVING S OF THE AREA TODAY WILL BRING -SN TO ALL TAF SITES...RESULTING IN IFR CONDITIONS. LIFR CONDITIONS ARE POSSIBLE AS WELL...ESPECIALLY AT KCMX...DURING PERIOD OF HEAVIEST SNOW. IMPROVEMENT EXPECTED W TO E LATE MORNING/AFTN AS MAIN AREA OF -SN EXITS. HOWEVER...IT MAY BE DIFFICULT TO GET RID OF THE LOWER CIGS GIVEN LIGHT LOW-LEVEL WINDS AND THUS WEAK ADVECTION OF ANY DRIER AIR AT THE LOW-LEVELS. SO...CIGS MAY REMAIN IFR OR ONLY RISE SLIGHTLY TO LOW MVFR IN THE AFTN. IWD IS THE MOST LIKELY TO SEE SIGNIFICANT IMPROVEMENT. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... A LOW PRESSURE SYSTEM OVER MN WILL MOVE EAST TODAY. ALTHOUGH WINDS SHOULD STAY BELOW GALE FORCE...THEY WILL BECOME RATHER GUSTY OUT OF THE SOUTHEAST WITH PERHAPS A GUST OR TWO CLOSE TO GALE FORCE. AFTER ANOTHER LOW MOVES ACROSS THE LOWER LAKES ON FRIDAY...A WEAK RIDGE BUILDS ACROSS LAKE SUPERIOR INTO SATURDAY BEFORE A STRONG LOW DEVELOPS OVER THE PLAINS AND MOVES NORTH OF LAKE SUPERIOR FOR NEW YEARS DAY. HIGH END NORTH-NORTHWEST GALES ARE POSSIBLE WITH THIS SYSTEM INTO MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ014- 085. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB DISCUSSION...JLB AVIATION...TITUS MARINE...TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
550 AM EST THU DEC 29 2011 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A STRONG WRLY MID/UPPER LEVEL FLOW INTO THE PAC NW AND WNW FLOW DOWNSTREAM FROM THE SRN CANADA AND NRN PLAINS INTO THE GREAT LAKES. ONE SHEARED SHORTWAVE TROUGH WAS LOCATED NORTH OF LAKE SUPERIOR AND ANOTHER WAS MOVING THROUGH SW MN. AT THE SFC...A 997 MB LOW WAS LOCATED OVER SRN MN RESULTING IN S TO SE WINDS ACROSS UPPER MICHIGAN. AN AREA OF SNOW FROM NE MN INTO WRN LAKE SUPERIOR NW WI WITH VSBYS INTO THE 1-3SM RANGE WAS SUPPORTED BY 285K-290K ASCENT AHEAD OF A 850-700 MB TROUGH. ANY LAKE EFFECT/ENHANCED SNOW OFF OF LAKE MICHIGAN WITH THE SRLY FLOW HAS BEEN MINIMAL WITH ONLY A DUSTING AT MOST. && .DISCUSSION... TODAY AND TONIGHT...EXPECT THE AREA OF SNOW TO PROGRESS ACROSS UPPER MICHIGAN TODAY. MODELS CONSENSUS QPF OF AROUND A TENTH OF AN INCH WITH SNOW/WATER RATIO VALUES NEAR 15/1 WOULD RESULT IN SNOWFALL AMOUNTS OF AN INCH OR TWO WHICH IS REASONABLE GIVEN 2G-3G/KG MOISTURE AVBL NEAR 700MB DURING A 6 HOUR PERIOD OF STRONGER LIFT. UNCERTAINTY REMAINS WITH REGARD TO LAKE ENHANCED SNOW POTENTIAL INTO THE SE CWA. THE HIGHER RES MODELS HAVE BEEN OVERDOING PCPN WITH BANDS OFF OF LAKE MICHIGAN SO FAR. HOWEVER...AS THE DEEPER MOISTURE ARRIVES...EXPECT THAT THE LAKE CONTRIBUTION MAY ADD AN ADDITIONAL 1-2 INCHES TO SNOWFALL AMOUNTS. SINCE THE WINDS WERE BACKING MORE SERLY AHEAD OF THE LOW...THE BEST LOW LEVEL CONV AND OVER WATER TRAJECTORIES HAVE SHIFTED TO THE WEST. SO...HAVE CANCELLED THE ADVY FOR LUCE COUNTY AND CONTINUED MENTION OF 2 TO 4 INCHES OF SNOW IN THE ADVY FOR SCHOOLCRAFT COUNTY TODAY. MODELS SUGGEST THAT THE DEEPER MOISTURE WILL QUICKLY DEPART THIS AFTERNOON OVER THE WEST. HOWEVER...LACK OF LOW LEVEL LIFT OR FOCUSING MECHANISM SHOULD MINIMIZE POTENTIAL FOR -FZDZ. SOME LIGHT SNOW WILL LINGER OVER THE ERN CWA TONIGHT AS THE SFC-850 MB TROUGH SLOWLY PIVOTS TO THE NORTHEAST. FRIDAY...MODELS WERE IN AGREEMENT THAT THE PCPN ASSOCIATED WITH A SHORTWAVE MOVING FROM THE PAC THROUGH THE NRN PLAINS INTO THE MS VALLEY AND SRN GREAT LAKES IS EXPECTED TO REMAIN SOUTH OF UPPER MI. SOME ISOLATED LIGHT SNOW SHOWERS MAY BE POSSIBLE NEAR AN INVERTED TROUGH AXIS INTO THE NRN CWA. AGAIN...-FZDZ MAY ALSO BE POSSIBLE BUT PROBABILITIES REMAIN LOW. SAT INTO SUN...THE NEXT MID LEVEL TROUGH IN THE PROGRESSIVE PATTERN WILL MOVE INTO THE REGION BY LATE SAT. WAA AHEAD OF THE MID LEVEL AND SFC TROUGH MAY BRING SOME LIGHT PCPN INTO THE WRN CWA. THE MORE CONSISTENT ECMWF WAS PREFERRED FOR DETAILS WITH THE SYSTEM AS THE GFS AND NAM HAVE AT TIMES SHOWED A STRONGER SHORTWAVE SWEEPING THROUGH THE REGION THAT WOULD GENERATE SUBSTANTIAL PCPN AND BRING MUCH GREATER DEEPENING OF THE SFC LOW. FALLING TEMPS AND BLUSTERY WNW WINDS ARE EXPECTED BY SUN AFTERNOON BEHIND A STRONG COLD FRONT. SUN NIGHT INTO TUE...AS THE PATTERN BRIEFLY AMPLIFIES...MUCH COLDER AIR WILL POUR INTO THE WRN LAKES ON NW TO N WINDS DROPPING 850 MB TEMPS TO AROUND -20C. SUBTLE MODEL DIFFERENCES REMAIN WITH THE PREVAILING WIND DIRECTION AS THE GFS REMAINS MORE TO THE NW COMPARED TO THE NRLY DIRECTION DEPICTED BY THE ECMWF/GEM. SIGNIFICANT LES REMAINS POSSIBLE WITH INTENSITY DROPPING OFF MON AS DEEPER MOISTURE DEPARTS. && .AVIATION /FOR THE 06Z TAF ISSUANCE/... AS NEXT LOW PRES SYSTEM APPROACHES FROM THE W...-SN WILL SPREAD ACROSS THE AREA OVERNIGHT THRU THE MORNING...RESULTING IN VFR CONDITIONS AT KIWD/KCMX/KSAW FALLING QUICKLY TO MVFR THEN IFR. LIFR CONDITIONS ARE POSSIBLE AS WELL...ESPECIALLY AT KCMX...DURING PERIOD OF HEAVIEST SNOW. IMPROVEMENT EXPECTED W TO E LATE MORNING/AFTN AS MAIN AREA OF -SN EXITS. HOWEVER...IT MAY BE DIFFICULT TO GET RID OF THE LOWER CIGS GIVEN LIGHT LOW-LEVEL WINDS AND THUS WEAK ADVECTION OF ANY DRIER AIR AT THE LOW-LEVELS. SO... CIGS MAY REMAIN IFR OR ONLY RISE SLIGHTLY TO LOW MVFR IN THE AFTN. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... A LOW PRESSURE SYSTEM OVER MN WILL MOVE EAST TODAY. ALTHOUGH WINDS SHOULD STAY BELOW GALE FORCE...THEY WILL BECOME RATHER GUSTY OUT OF THE SOUTHEAST WITH PERHAPS A GUST OR TWO CLOSE TO GALE FORCE. AFTER ANOTHER LOW MOVES ACROSS THE LOWER LAKES ON FRIDAY...A WEAK RIDGE BUILDS ACROSS LAKE SUPERIOR INTO SATURDAY BEFORE A STRONG LOW DEVELOPS OVER THE PLAINS AND MOVES NORTH OF LAKE SUPERIOR FOR NEW YEARS DAY. HIGH END NORTH-NORTHWEST GALES ARE POSSIBLE WITH THIS SYSTEM INTO MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ014- 085. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SYNOPSIS...JLB DISCUSSION...JLB AVIATION...ROLFSON MARINE...TITUS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1143 PM CST WED DEC 28 2011 .AVIATION... /06Z TAF ISSUANCE/ THREAT FOR FREEZING RAIN LINGERS AT KSTC...KRNH AND KEAU UNTIL 08Z AS LOW PRESSURE AND A WARM FRONT MOVE THROUGH. CEILINGS ARE BEGINNING TO DETERIORATE ALONG AND AHEAD OF A WARM FRONT. EXPECT MVFR TO SETTLE IN BETWEEN 09Z AND 11Z AND LAST THROUGH MUCH OF THE MORNING BEFORE SCATTERING OUT IN THE EARLY AFTERNOON. ANOTHER WAVE OF LOW PRESSURE WILL MOVE ACROSS THURSDAY NIGHT...MUCH LIKE THE CURRENT ONE. HOWEVER...THE LOW TOMORROW NIGHT WILL BE STRONGER AND PROFILE DATA SUGGESTS IT WILL BE COLDER. HENCE...SNOW IS THE MAIN EVENT. MODEL TRENDS ARE PAINTING A PRETTY BLEAK PICTURE FOR KMSP AND KRNH AND KEAU WITH SNOW ACCUMULATION DURING THE LATE EVENING AND OVERNIGHT HOURS. MVFR OR LOWER CEILINGS/VISIBILITIES WILL ACCOMPANY THE SNOW. KMSP...LIGHT RAIN PUSHING EAST OF THE AIRFIELD WITH BKN-OVC035-040 FOR A FEW HOURS. MVFR CEILINGS STILL EXPECTED TOWARDS DAYBREAK IN THE WAKE OF A LOW PRESSURE SYSTEM MOVING INTO WEST CENTRAL MN ATTM. THESE SHOULD PERSIST THROUGH THE MORNING WITH A VFR AFTERNOON. POTENTIAL FOR MVFR OR LOWER CEILINGS QUITE HIGH FOR THURSDAY NIGHT AND FRIDAY MORNING AS ANOTHER WAVE OF LOW PRESSURE MOVES THROUGH. SNOW SHOULD ACCOMPANY THIS ONE TOMORROW NIGHT WITH SOME ACCUMULATION POSSIBLE. && .UPDATED... /ISSUED 816 PM CST WED DEC 28 2011/ HAVE ISSUED A WINTER WEATHER ADVISORY THROUGH 3 AM THURSDAY FOR MUCH OF CENTRAL MN AND WEST CENTRAL WI. LIGHT RAIN HAS SPREAD INTO WEST CENTRAL MN THIS EVENING AHEAD OF A LOW PRESSURE SYSTEM OVER ND. TEMPERATURES ARE IN THE MIDDLE 30S AROUND ALEXANDRIA BUT FURTHER EAST TEMPERATURES ARE AT OR BELOW FREEZING. PAVEMENT TEMPERATURES ACROSS CENTRAL MN AND PARTS OF WEST CENTRAL WI ARE AROUND 30 DEGREES AS WELL. HENCE...THE POTENTIAL FOR FREEZING RAIN IS INCREASING. COMPLICATING MATTERS IS THAT ICE INCREASES IN THE COLUMN TO THE NORTH AND EAST OF THE TWIN CITIES WITH THE PRECIP TYPE MORE LIKELY TO BE SNOW WITH A CHANCE OF FREEZING RAIN. && .DISCUSSION... /ISSUED 352 PM CST WED DEC 28 2011/ SUMMARY...PATTERN IS A BIT MORE ACTIVE OVER THE NEXT SEVERAL DAYS IN TERMS OF CHANCES OF PRECIPITATION THAN IT HAS BEEN IN QUITE SOME TIME. OVERALL...THE OUTLOOK REMAINS WARM SO THE PRECIP EVENTS EXPECTED TONIGHT...THURSDAY NIGHT AND SATURDAY NIGHT WILL LIKELY HAVE SOME LIQUID PRECIPITATION ASSOCIATED WITH EACH OF THEM. NO MAJOR SYSTEMS EXPECTED AND MAXIMUM QPF WITH EACH EVENT SHOULD LARGELY BE BELOW A QUARTER INCH...A COUPLE OUTLIER RUNS OF THE NAM/GEM WOULD SUGGEST HIGHER QPF TOTALS WITH THE THURSDAY NIGHT AND SATURDAY NIGHT SYSTEMS. THE INTERIOR OF CANADA HAS COOLED SINCE THE LAST TIME I WAS ON A FORECAST SHIFT LATE LAST WEEK...BUT STILL NO TRUE ARCTIC AIR ENCROACHING ON THE US CONUS. THE ARCTIC AIR IS STILL BEING CONFINED TO THE HIGHER LATITUDES...LARGELY ABOVE 55-60 DEGREES NORTH. PACIFIC AIR MASSES WILL CONTINUE TO IMPACT THE US THROUGH THE END OF THE YEAR. PROGRESSIVE UPPER FLOW WILL BE FEATURED AS A SERIES OF DISTURBANCES SURGE FROM THE NORTHEASTERN PACIFIC AND INTO THE PACIFIC NORTHWEST. THE SOUTHWARD EXTENT OF THIS UPPER TROUGH SHOULD BE LIMITED BY A RIDGE ACROSS THE SOUTHWEST US. AS A RESULT...THE SWATH OF PRECIPITATION SHOULD NOT EXTEND MUCH FARTHER SOUTH THAN 40 DEGREES NORTH. THIS WILL KEEP MN AND WI UNDER THE GUN FOR A FEW LIGHT PRECIPITATION EVENTS OVER THE COMING DAYS. THE FAST MOVING FLOW ALOFT WILL KEEP UNSETTLED CONDITIONS IN PLACE FOR MUCH OF THE PACIFIC NORTHWEST...NORTHERN ROCKIES AND UPPER MISSISSIPPI VALLEY THROUGH THE WEEKEND. THE FIRST IN A PAIR OF SYSTEMS IS CURRENTLY MOVING OUT OF THE NORTHERN ROCKIES AND INTO THE NORTHERN PLAINS. LIGHT RAIN IS RAPIDLY PUSHING INTO THE EASTERN DAKOTAS LATE THIS AFTERNOON AND THE HRRR TREND IS TAKE THE LIGHT RAIN INTO WESTERN MN BETWEEN 00-03Z. IF THE CURRENT TRENDS HOLD...MOST OF THE PRECIP WILL PUSH OUT OF THE FORECAST AREA BETWEEN 06-09Z...A BIT FASTER THAN THE CURRENT FORECAST INDICATES. ALSO SOME QUESTION WHETHER OR NOT THE MIXED PRECIPITATION WILL REALLY PAN OUT IN PARTS OF CENTRAL/SOUTHERN MN. COOLING WILL BE TOUGH WITH CLOUD COVER AND WEAK WARM AIR ADVECTION. IT MIGHT END UP BEING NEARLY ALL LIGHT RAIN RATHER THAN SNOW OR FREEZING RAIN. IN THE EXTENDED...INCREASINGLY MERIDIONAL FLOW WILL LEAD TO MORE AMPLIFIED TROUGHS ACROSS THE EASTERN PACIFIC THROUGH THE GREAT LAKES WITH RIDGING SANDWICHED IN BETWEEN. MOST OF THE GUIDANCE AGREES ON THIS PATTERN...OUTSIDE THE 00Z GFS WHICH WAS BROAD AND FLAT WITH THE EASTERN TROUGH DESPITE ITS AMPLIFIED RIDGE UPSTREAM. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...WINTER WEATHER ADVISORY UNTIL 3 AM CST THURSDAY FOR BENTON- CHISAGO-ISANTI-KANABEC-MILLE LACS-MORRISON-SHERBURNE- STEARNS-TODD. WI...WINTER WEATHER ADVISORY UNTIL 3 AM CST THURSDAY FOR BARRON- CHIPPEWA-DUNN-EAU CLAIRE-POLK-RUSK-ST. CROIX. && $$ RAH/RAH/CLF
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
326 PM CST THU DEC 29 2011 .UPDATE... .AVIATION... MID AND HIGH LEVEL CLOUDS WILL CONTINUE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THIS AFTERNOON...WITH SKIES CLEARING TONIGHT. CEILINGS MAY GET AS LOW AS 5000 FT AGL...ALONG WITH SCT RAIN SHOWERS AND A FEW THUNDERSTORMS LATE THIS AFTERNOON AND EARLY THIS EVENING. OVERALL VFR EXPECTED TO PREVAIL...WITH GUSTY WEST WINDS TO 40 KTS WEST OF HIGHWAY 183 FROM LATE AFTERNOON THROUGH THE EVENING. LOCAL GUSTS TO 50 KTS ARE POSSIBLE INVOF SHOWERS/STORMS. && .PREV DISCUSSION... /ISSUED 321 PM CST THU DEC 29 2011/ DISCUSSION... SHORT TERM... WIND ADVISORY CONDITIONS ARE SPREADING THROUGH ALL OF THE WRN NEB PANHANDLE THIS AFTERNOON. THERE IS THE POTENTIAL FOR STRONG WINDS TO SPREAD THROUGH ALL OF THE PANHANDLE UNTIL 23Z. THEREAFTER THE LOSS OF DAYTIME HEATING SHOULD CAUSE A DROP IN GUSTS. 30 MPH SUSTAINED CONDITIONS MIGHT CONTINUE THIS EVENING AS LOW PRESSURE TRACKS THROUGH THE MISSOURI BASIN. THE RUC SHOWS A PRONOUNCED TROP FOLD ON THE PV15 SURFACE WHICH SHOULD MOVE THRU THE FCST AREA THIS EVENING. THUS THE WIND ADZY WILL CONTINUE ACROSS GARDEN AND DEUEL COUNTIES WITH A POSSIBLE NORTH AND EAST EXPANSION AS CONDITIONS WARRANT. SCATTERED SHOWERS ISOLATED THUNDERSTORMS ARE EXPECTED TO CONTINUE TRACKING THRU NRN NEB THIS EVENING. THE STRONG WEST WINDS ARE BEING USHERED IN AHEAD OF A PACIFIC COLD FRONT WORKING THRU NERN WY. THE FRONT SHOULD COOL TEMPS OFF SOMEWHAT FOR FRIDAY WITH HIGHS ABOUT 10F COOLER THAN TODAY. ANOTHER STRONG COLD FRONT IS EXPECTED TO MOVE THROUGH SATURDAY MORNING...EARLY AFTERNOON. THIS FRONT IN COMBINATION WITH DEEPENING LOW PRESSURE ACROSS THE UPPER MIDWEST AND VERY STRONG PACIFIC HIGH PRESSURE SHOULD PRODUCE WIND ADVISORY CONDITIONS ACROSS MOST AND POSSIBLY ALL OF THE FCST AREA. A BLEND OF MODEL DATA AND GUIDANCE WAS USED FOR THE FCST WHICH PRODUCED HIGH END WIND ADVISORY CONDITIONS ACROSS SWRN NEB. AMPLE MOISTURE WILL BE PRESENT ALONG AND BEHIND THE FRONT SATURDAY FOR SCATTERED RAIN AND SNOW SHOWERS...MAINLY ACROSS THE NORTH. ANOTHER STRONG TROP FOLD WILL SWEEP THE FCST AREA IN CONCERT WITH THE FRONTAL PASSAGE. THE GFS WAS OVERPOWERING WITH THE WIND STRENGTH AND COLD AIR PRODUCING ALL SNOW WHILE THE NAM SHOWED A MIX WITH WEAKER WINDS. THE WARMER NAM WAS PREFERRED. PACIFIC HIGH PRESSURE WILL BUILD ACROSS THE FCST AREA SUNDAY PRODUCING HIGHS IN THE UPPER 30S TO AROUND 40 WITH NEARLY CLEAR SKIES. LONG TERM... A RIDGE OF HIGH PRESSURE ALOFT WILL BE AMPLIFYING MONDAY ACROSS THE ROCKIES...WHILE A TROUGH OF LOW PRESSURE CONTINUES IT/S EASTWARD PROGRESSION INTO THE NORTHEAST STATES. OUR AREA WILL BE IN BETWEEN THESE TWO FEATURES...WITH A BROAD NORTHWEST FLOW ALOFT. 850 MB TEMPERATURES WILL BEGIN TO RECOVER MONDAY...AND CONTINUE TO WARM THOUGH THURSDAY. IN FACT BY THURSDAY MODELS ARE SUGGESTING +15C OVER THE AREA...WHICH WOULD PUT HIGH TEMPERATURES INTO POSSIBLE RECORD TERRITORY. SO AFTER A COOL START MONDAY...HIGHS MID 30S TO MID 40S...TUESDAY THROUGH THURSDAY LOOKING VERY MILD. COULD BE PUSHING 60 DEGREES OR WARMER AGAIN BY THURSDAY. AVIATION... MID AND HIGH LEVEL CLOUDS WILL CONTINUE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THIS AFTERNOON...WITH SKIES CLEARING TONIGHT. CEILINGS MAY GET AS LOW AS 5000 FT AGL...ALONG WITH A FEW RAIN SHOWERS...ACROSS NORTH CENTRAL NEBRASKA LATE THIS AFTERNOON AND EARLY THIS EVENING. VFR EXPECTED TO PREVAIL...WITH GUSTY WEST WINDS TO 30 KTS WEST OF HIGHWAY 83 FROM LATE AFTERNOON THROUGH THE EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 11 PM MST THIS EVENING FOR NEZ022-056. && $$ SHORT TERM...CDC AVIATION/EXTENDED...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
321 PM CST THU DEC 29 2011 .DISCUSSION... .SHORT TERM... WIND ADVISORY CONDITIONS ARE SPREADING THROUGH ALL OF THE WRN NEB PANHANDLE THIS AFTERNOON. THERE IS THE POTENTIAL FOR STRONG WINDS TO SPREAD THROUGH ALL OF THE PANHANDLE UNTIL 23Z. THEREAFTER THE LOSS OF DAYTIME HEATING SHOULD CAUSE A DROP IN GUSTS. 30 MPH SUSTAINED CONDITIONS MIGHT CONTINUE THIS EVENING AS LOW PRESSURE TRACKS THROUGH THE MISSOURI BASIN. THE RUC SHOWS A PRONOUNCED TROP FOLD ON THE PV15 SURFACE WHICH SHOULD MOVE THRU THE FCST AREA THIS EVENING. THUS THE WIND ADZY WILL CONTINUE ACROSS GARDEN AND DEUEL COUNTIES WITH A POSSIBLE NORTH AND EAST EXPANSION AS CONDITIONS WARRANT. SCATTERED SHOWERS ISOLATED THUNDERSTORMS ARE EXPECTED TO CONTINUE TRACKING THRU NRN NEB THIS EVENING. THE STRONG WEST WINDS ARE BEING USHERED IN AHEAD OF A PACIFIC COLD FRONT WORKING THRU NERN WY. THE FRONT SHOULD COOL TEMPS OFF SOMEWHAT FOR FRIDAY WITH HIGHS ABOUT 10F COOLER THAN TODAY. ANOTHER STRONG COLD FRONT IS EXPECTED TO MOVE THROUGH SATURDAY MORNING...EARLY AFTERNOON. THIS FRONT IN COMBINATION WITH DEEPENING LOW PRESSURE ACROSS THE UPPER MIDWEST AND VERY STRONG PACIFIC HIGH PRESSURE SHOULD PRODUCE WIND ADVISORY CONDITIONS ACROSS MOST AND POSSIBLY ALL OF THE FCST AREA. A BLEND OF MODEL DATA AND GUIDANCE WAS USED FOR THE FCST WHICH PRODUCED HIGH END WIND ADVISORY CONDITIONS ACROSS SWRN NEB. AMPLE MOISTURE WILL BE PRESENT ALONG AND BEHIND THE FRONT SATURDAY FOR SCATTERED RAIN AND SNOW SHOWERS...MAINLY ACROSS THE NORTH. ANOTHER STRONG TROP FOLD WILL SWEEP THE FCST AREA IN CONCERT WITH THE FRONTAL PASSAGE. THE GFS WAS OVERPOWERING WITH THE WIND STRENGTH AND COLD AIR PRODUCING ALL SNOW WHILE THE NAM SHOWED A MIX WITH WEAKER WINDS. THE WARMER NAM WAS PREFERRED. PACIFIC HIGH PRESSURE WILL BUILD ACROSS THE FCST AREA SUNDAY PRODUCING HIGHS IN THE UPPER 30S TO AROUND 40 WITH NEARLY CLEAR SKIES. .LONG TERM... A RIDGE OF HIGH PRESSURE ALOFT WILL BE AMPLIFYING MONDAY ACROSS THE ROCKIES...WHILE A TROUGH OF LOW PRESSURE CONTINUES IT/S EASTWARD PROGRESSION INTO THE NORTHEAST STATES. OUR AREA WILL BE IN BETWEEN THESE TWO FEATURES...WITH A BROAD NORTHWEST FLOW ALOFT. 850 MB TEMPERATURES WILL BEGIN TO RECOVER MONDAY...AND CONTINUE TO WARM THOUGH THURSDAY. IN FACT BY THURSDAY MODELS ARE SUGGESTING +15C OVER THE AREA...WHICH WOULD PUT HIGH TEMPERATURES INTO POSSIBLE RECORD TERRITORY. SO AFTER A COOL START MONDAY...HIGHS MID 30S TO MID 40S...TUESDAY THROUGH THURSDAY LOOKING VERY MILD. COULD BE PUSHING 60 DEGREES OR WARMER AGAIN BY THURSDAY. && .AVIATION... MID AND HIGH LEVEL CLOUDS WILL CONTINUE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA THIS AFTERNOON...WITH SKIES CLEARING TONIGHT. CEILINGS MAY GET AS LOW AS 5000 FT AGL...ALONG WITH A FEW RAIN SHOWERS...ACROSS NORTH CENTRAL NEBRASKA LATE THIS AFTERNOON AND EARLY THIS EVENING. VFR EXPECTED TO PREVAIL...WITH GUSTY WEST WINDS TO 30 KTS WEST OF HIGHWAY 83 FROM LATE AFTERNOON THROUGH THE EVENING. && .LBF WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 11 PM MST THIS EVENING FOR NEZ022-056. && $$ SHORT TERM...CDC AVIATION/EXTENDED...TAYLOR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
915 PM EST FRI DEC 30 2011 .SYNOPSIS... A COLD FRONT WILL PUSH OFF THE COAST SATURDAY MORNING...HOWEVER NO SIGNIFICANT COOLING IS EXPECTED IN THE WAKE OF THIS FRONT. A STRONGER COLD FRONT PASSING THROUGH SUNDAY EVENING WILL BE FOLLOWED BY THE COLDEST AIR-MASS OF THE SEASON. COLD AIR WILL PERSIST THROUGH MID-WEEK BEFORE A WARMING TREND COMMENCES. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 915 PM FRIDAY...LATEST NAM MODEL INDICATES 1K TO 8H THICKNESSES TO INCREASE AHEAD OF THE COLD FRONT DURING TONIGHT. MINS HAVE BEEN ADJUSTED TO OR SLIGHTLY HIGHER THAN MODEL MOS GUIDANCE. LATEST HRRR AND NAM INDICATES NO PCPN ACROSS THE ILM INLAND LOCALES...HOWEVER THEY WANT TO DEVELOP PCPN IMMEDIATELY ALONG THE COAST...MAINLY ALONG THE PRE-FRONTAL TROF DURING THE PRE-DAWN HRS OF SATURDAY. UP TO ONE TENTH OF AN INCH IS SHOWN BY HRRR. AGAIN WITH LIMITED MOISTURE THRU THE ATM COLUMN...EXCEPT BETWEEN MIDNIGHT AND 7AM WHEN MOISTURE ASSOCIATED WITH THE PRE-FRONTAL TROF AND THE FRONT ITSELF TRACKS ACROSS THE FA. UVVS FROM THE DYNAMICS FROM THE UPPER VORT ASSOCIATED WITH THE PROGRESSIVE 5H S/W TROF...TO AID IN THE DEVELOPMENT OF ISOLATED -SHRA AHEAD OF THE PRE-FRONT TROF AND THE FRONT ITSELF OVER LAND AREAS LATER TONIGHT...NOT ENOUGH TO WARRANT A POP THOUGH. THE MAJORITY OF THE PCPN TO DEVELOP ALONG THE ADJACENT ATL WATERS...BASICALLY ALONG THE WEST WALL OF THE GULF STREAM TOWARDS DAYBREAK WHERE OCEAN SFC BASED PARAMETERS AID SHOWER DEVELOPMENT. WITH ALL OF THIS SAID ALONG WITH THE LATEST MOSAIC 88DS AND SATELLITE INFO INJECTED INTO THE EQUATION...HAVE CONTINUED TO KEEP THE ILM CWA PCPN-LESS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 230 PM FRIDAY...PROGRESSIVE PATTERN WILL PERSIST THROUGH THE SHORT TERM PERIOD. THE INITIAL SHORTWAVE AND SURFACE COLD FRONT WILL SHIFT OFF THE EAST COAST EARLY SATURDAY FOLLOWED BY WEAK RIDGING ALOFT SATURDAY NIGHT INTO SUNDAY MORNING. A DEEPER TROUGH WILL EVOLVE OVER THE EASTERN STATES BY SUNDAY NIGHT. THE SECOND STRONGER COLD FRONT PASSING THROUGH SUNDAY EVENING WILL BE FOLLOWED BY AN ARCTIC AIR-MASS. OTHER THAN SOME CLOUDS SATURDAY MORNING NOT MUCH MOISTURE FOR EITHER OF THE FRONTS TO TAP INTO THUS NO POPS REQUIRED. MAX TEMPERATURES WILL BE WELL ABOVE NORMAL EACH DAY. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 230 PM FRIDAY...MAJOR COLD SNAP ON TAP FOR THE EXTENDED AS AN ARCTIC AIRMASS DESCENDS UPON THE CAROLINAS. ECMWF AND GFS LONG RANGE PRODUCTS IN DECENT AGREEMENT AS TO THE GENERAL SCENARIO...WITH A DEEP H/5 TROUGH DROPPING SOUTH OVER EASTERN CONUS ON MONDAY... PUSHING AN ARCTIC FRONT WELL OFFSHORE EARLY IN THE PERIOD. A SERIES OF SHORT WAVES WILL DEEPEN AND REINFORCE THE L/W TROUGH OVER THE EASTERN SEABOARD...ESPECIALLY ON TUESDAY WHEN 1000-500MB THICKNESS VALUES WILL DROP DOWN TO AROUND 520 DECAMETERS. TIME-HEIGHT CROSS SECTIONS SHOW A GENERALLY DRY AIR MASS SO DO NOT EXPECT ANY PRECIPITATION DURING THIS PERIOD. TEMPERATURES WILL BE WELL BELOW NORMAL THROUGH THE EXTENDED...WITH LOWS IN THE 20S THROUGH THURSDAY MORNING. TUESDAY LOOKS TO BE THE COLDEST DAY WITH STRONG COLD AIR ADVECTION IN PLACE. EXPECTING HIGHS IN THE LOWER 40S ON TUESDAY...WITH LOWS TUESDAY NIGHT OF AROUND 20 MANY LOCATIONS... PERHAPS DROPPING INTO THE TEENS IN OUR NORMALLY COLDER LOCATIONS. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 2330Z...FORECAST LOOKS ON TRACK FOR THIS EVENING INTO THE OVERNIGHT PERIOD AS CLEAR SKIES DOMINATE. CONFIDENCE REMAINS HIGH THROUGH ABOUT 06Z WITH SKIES GRADUALLY BECOMING PARTLY CLOUDY AHEAD OF ADVANCING COLD FRONT TO OUR WEST. FRONT MOVES ACROSS THE TERMINALS BETWEEN 11Z-14Z GIVE OR TAKE AN HOUR AND CEILINGS SHOULD DEVELOP BETWEEN 5K-8K AS A STRATOCUMULUS DECK. NAM/GFS SHOWING SOME LIMITED MOISTURE AVAILABLE WITH THE FRONT BUT LOOKS TO DRY OUT AS IT REACHES THE COAST. PREVIOUS FORECAST HAD VCSH AT A FEW TERMINALS...WILL MENTION AT LBT...FLO AND ILM BUT DO NOT REALLY THINK WE WILL SEE MUCH AS ATMOSPHERE IS PRETTY DRY. MODEL SOUNDINGS SHOW LIMITED MOISTURE BETWEEN 900MB-750MB WITH AN INVERSION BELOW THAT WHICH MIXES OUT BETWEEN 12Z AND 18Z. WILL MENTION SOME GUSTS IN THE TERMINALS AFTER SUNRISE TO ACCOUNT FOR THIS. THE FRONT THAT WILL PASS THROUGH IS WEAK...WILL EXPECT WIND SHIFT FROM WEST TO EAST BETWEEN 11Z-14Z. PREVIOUS FORECAST MENTIONS...PATCHY AREAS OF LIGHT RAIN WILL MOVE ACROSS MAINLY SOUTHEASTERN NORTH CAROLINA THIS EVENING AND OVERNIGHT BUT DO NOT EXPECT IT TO SIGNIFICANTLY AFFECT FLIGHT OPERATIONS. WESTERLY WINDS 10-15 KNOTS EXPECTED AFTER SUNRISE WITH SCATTERED LOW CLOUDS. EXTENDED OUTLOOK...POSSIBLE IFR SUNDAY MORNING INLAND TERMINALS. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 915 PM FRIDAY...COLD SHELF WATERS LIMITING THE WAA WINDS AHEAD OF THE COLD FRONT TO SW 10-15 KT. THE WARMER SHELF WATERS...IE. 70 DEGREES AT FPSN7...JUST OUTSIDE THE COASTAL WATERS OFF CAPE FEAR WILL DEFINITELY SEE THE HIGHER WINDS MIX DOWN TO THE OCEAN SFC. LOW LEVEL JET AHEAD OF THE COLD FRONT WITH 925MB 30-40 KT SW WINDS PROGGED...WILL HAVE A BETTER CHANCE TO MIX DOWN TO THE OCEAN SFC WHERE SSTS ARE IN THE UPPER 60S AND HIGHER. THE COOLER SHELF WATERS WILL LIMIT OVERALL SW WINDS TO 10-15 KT. THE OTHER DRIVING FORCE WILL BE FROM THE TIGHTENING SFC PG AHEAD OF THE COLD FRONT. THIS COULD BOOST WINDS A BIT HIGHER. HAVE INDICATED SW 15-20 KT WINDS ACROSS THE OUTER WATERS OF THE ILM COASTAL WATERS. WILL HAVE TO MONITOR THE SFC PG AND LIKELY ISSUE WIND SPEED UPDATES IF THE SFC PG FURTHER TIGHTENS AS OPPOSED TO WINDS MIXING DOWN FROM ALOFT. DOMINATE SEAS EARLY THIS EVENING ARE FROM A 1 TO 2 FOOT DECAYING EASTERLY SWELL AT 12-14 SECOND PERIODS. SHORT PERIOD WIND DRIVEN WAVES WILL LIKELY DOMINATE SIG. SEAS BY AND AFTER MIDNIGHT. THE OUTER WATERS OFF CAPE FEAR WILL HAVE THE BEST POTENTIAL TO REACH SCEC/SCA CRITERIA DEPENDING HOW CLOSE THOSE WARMER SSTS REACH. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 230 PM FRIDAY...WESTERLY FLOW IN THE WAKE OF A COLD FRONT SATURDAY MORNING WILL RANGE FROM 15-20 KT AWAY FROM THE COAST AND 10-15 KT NEAR SHORE. THE OFFSHORE DIRECTION WILL LIMIT WAVE GROWTH NEARSHORE AS WELL...BUT SEAS AWAY FROM THE COAST SATURDAY WILL BE 3-5 FT (HIGHEST OFF CAPE FEAR). WINDS WILL DIMINISH SATURDAY NIGHT THEN BEGIN TO BACK TO THE SOUTHWEST SUNDAY MORNING. THE PRESSURE GRADIENT WILL INCREASE DURING SUNDAY AHEAD OF THE NEXT COLD FRONT THAT IS EXPECTED TO CROSS THE WATERS SUNDAY EVENING. COULD SEE A BRIEF PERIOD OF SMALL CRAFT CONDITIONS BY SUNDAY EVENING. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 230 PM FRIDAY...A STRONG ARCTIC COLD FRONT WILL MOVE ACROSS THE WATERS EARLY ON MONDAY...BRINGING STRONG NWLY WINDS AND HAZARDOUS SEAS TO THE COASTAL WATERS THROUGH THE LONG TERM. COLD SURGE LOOKS TO BE THE COLDEST ON TUESDAY MORNING...WITH NW WINDS IN THE 20 TO 30 KT RANGE...AND SEAS BUILDING TO 6 FT OR SO OVER THE OUTER PORTIONS OF OUR WATERS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SRP NEAR TERM...DCH SHORT TERM...SRP LONG TERM...REK AVIATION...MAC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
655 PM EST FRI DEC 30 2011 .SYNOPSIS... A COLD FRONT WILL PUSH OFF THE COAST SATURDAY MORNING...HOWEVER NO SIGNIFICANT COOLING IS EXPECTED IN THE WAKE OF THIS FRONT. A STRONGER COLD FRONT PASSING THROUGH SUNDAY EVENING WILL BE FOLLOWED BY THE COLDEST AIR-MASS OF THE SEASON. COLD AIR WILL PERSIST THROUGH MID-WEEK BEFORE A WARMING TREND COMMENCES. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 645 PM FRIDAY...LATEST NAM MODEL INDICATES 1K TO 8H THICKNESSES TO INCREASE AHEAD OF THE COLD FRONT TONIGHT. 8H TEMPS TO REMAIN RELATIVELY STEADY OVERNIGHT. WILL INCREASE THE CWAS MINS TONIGHT BY 1 TO 3 DEGREES. LATEST HRRR INDICATES NO PCPN INLAND...HOWEVER IT WANTS TO DEVELOP PCPN IMMEDIATELY ALONG THE IMMEDIATE COAST...MAINLY ALONG THE PRE-FRONTAL TROF DURING THE PRE-DAWN HRS OF SATURDAY. WITH LIMITED MOISTURE THRU THE ATM COLUMN...EXCEPT BETWEEN MIDNIGHT AND 7AM WHEN MOISTURE ASSOCIATED WITH THE PRE-FRONTAL TROF AND THE FRONT ITSELF TRACKS ACROSS THE FA. UVVS FROM THE DYNAMICS FROM THE UPPER VORT ASSOCIATED WITH THE PROGRESSIVE 5H S/W TROF...DEVELOPS ISOLATED -SHRA AHEAD OF THE FRONT OVER LAND. THE MAJORITY OF THE PCPN TO DEVELOP ALONG THE ADJACENT ATL WATERS ALONG THE WEST WALL OF THE GULF STREAM TOWARDS DAYBREAK. WITH ALL OF THIS SAID ALONG WITH THE LATEST MOSAIC 88DS AND SATELLITE INFO...HAVE CONTINUED WITH A PCPN-LESS FORECAST. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 230 PM FRIDAY...PROGRESSIVE PATTERN WILL PERSIST THROUGH THE SHORT TERM PERIOD. THE INITIAL SHORTWAVE AND SURFACE COLD FRONT WILL SHIFT OFF THE EAST COAST EARLY SATURDAY FOLLOWED BY WEAK RIDGING ALOFT SATURDAY NIGHT INTO SUNDAY MORNING. A DEEPER TROUGH WILL EVOLVE OVER THE EASTERN STATES BY SUNDAY NIGHT. THE SECOND STRONGER COLD FRONT PASSING THROUGH SUNDAY EVENING WILL BE FOLLOWED BY AN ARCTIC AIR-MASS. OTHER THAN SOME CLOUDS SATURDAY MORNING NOT MUCH MOISTURE FOR EITHER OF THE FRONTS TO TAP INTO THUS NO POPS REQUIRED. MAX TEMPERATURES WILL BE WELL ABOVE NORMAL EACH DAY. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 230 PM FRIDAY...MAJOR COLD SNAP ON TAP FOR THE EXTENDED AS AN ARCTIC AIRMASS DESCENDS UPON THE CAROLINAS. ECMWF AND GFS LONG RANGE PRODUCTS IN DECENT AGREEMENT AS TO THE GENERAL SCENARIO...WITH A DEEP H/5 TROUGH DROPPING SOUTH OVER EASTERN CONUS ON MONDAY... PUSHING AN ARCTIC FRONT WELL OFFSHORE EARLY IN THE PERIOD. A SERIES OF SHORT WAVES WILL DEEPEN AND REINFORCE THE L/W TROUGH OVER THE EASTERN SEABOARD...ESPECIALLY ON TUESDAY WHEN 1000-500MB THICKNESS VALUES WILL DROP DOWN TO AROUND 520 DECAMETERS. TIME-HEIGHT CROSS SECTIONS SHOW A GENERALLY DRY AIR MASS SO DO NOT EXPECT ANY PRECIPITATION DURING THIS PERIOD. TEMPERATURES WILL BE WELL BELOW NORMAL THROUGH THE EXTENDED...WITH LOWS IN THE 20S THROUGH THURSDAY MORNING. TUESDAY LOOKS TO BE THE COLDEST DAY WITH STRONG COLD AIR ADVECTION IN PLACE. EXPECTING HIGHS IN THE LOWER 40S ON TUESDAY...WITH LOWS TUESDAY NIGHT OF AROUND 20 MANY LOCATIONS... PERHAPS DROPPING INTO THE TEENS IN OUR NORMALLY COLDER LOCATIONS. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 2330Z...FORECAST LOOKS ON TRACK FOR THIS EVENING INTO THE OVERNIGHT PERIOD AS CLEAR SKIES DOMINATE. CONFIDENCE REMAINS HIGH THROUGH ABOUT 06Z WITH SKIES GRADUALLY BECOMING PARTLY CLOUDY AHEAD OF ADVANCING COLD FRONT TO OUR WEST. FRONT MOVES ACROSS THE TERMINALS BETWEEN 11Z-14Z GIVE OR TAKE AN HOUR AND CEILINGS SHOULD DEVELOP BETWEEN 5K-8K AS A STRATOCUMULUS DECK. NAM/GFS SHOWING SOME LIMITED MOISTURE AVAILABLE WITH THE FRONT BUT LOOKS TO DRY OUT AS IT REACHES THE COAST. PREVIOUS FORECAST HAD VCSH AT A FEW TERMINALS...WILL MENTION AT LBT...FLO AND ILM BUT DO NOT REALLY THINK WE WILL SEE MUCH AS ATMOSPHERE IS PRETTY DRY. MODEL SOUNDINGS SHOW LIMITED MOISTURE BETWEEN 900MB-750MB WITH AN INVERSION BELOW THAT WHICH MIXES OUT BETWEEN 12Z AND 18Z. WILL MENTION SOME GUSTS IN THE TERMINALS AFTER SUNRISE TO ACCOUNT FOR THIS. THE FRONT THAT WILL PASS THROUGH IS WEAK...WILL EXPECT WIND SHIFT FROM WEST TO EAST BETWEEN 11Z-14Z. PREVIOUS FORECAST MENTIONS...PATCHY AREAS OF LIGHT RAIN WILL MOVE ACROSS MAINLY SOUTHEASTERN NORTH CAROLINA THIS EVENING AND OVERNIGHT BUT DO NOT EXPECT IT TO SIGNIFICANTLY AFFECT FLIGHT OPERATIONS. WESTERLY WINDS 10-15 KNOTS EXPECTED AFTER SUNRISE WITH SCATTERED LOW CLOUDS. EXTENDED OUTLOOK...POSSIBLE IFR SUNDAY MORNING INLAND TERMINALS. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 645 PM FRIDAY...COLD SHELF WATERS LIMITING THE WAA AHEAD OF THE COLD FRONT TO SW 10-15 KT. THE WARMER SHELF WATERS...IE. 70 DEGREES AT FPSN7...JUST OUTSIDE THE COASTAL WATERS OFF CAPE FEAR WILL DEFINITELY SEE THE HIGHER WINDS MIX DOWN TO THE OCEAN SFC. LOW LEVEL JET AHEAD OF THE COLD FRONT WITH 925MB 30-40 KT SW WINDS PROGGED...WILL HAVE A BETTER CHANCE TO MIX DOWN TO THE OCEAN SFC WHERE SSTS ARE IN THE UPPER 60S AND HIGHER. THE COOLER SHELF WATERS WILL LIMIT SW WINDS AT 10-15 KT. THE OTHER DRIVING FORCE WILL BE FROM THE TIGHTENING SFC PG AHEAD OF THE COLD FRONT. THIS COULD BOOST WINDS TO NEAR SCEC OF SCA CRITERIA. SEAS INITIALLY WILL BE FROM A 1 TO 2 FOOT DECAYING EASTERLY SWELL AT 12-14 SECOND PERIODS. SHORT PERIOD WIND DRIVEN WAVES WILL DOMINATE SIG. SEAS BY AND AFTER MIDNIGHT. THE OUTER WATERS OFF CAPE FEAR WILL HAVE THE BEST POTENTIAL TO REACH SCEC/SCA CRITERIA DEPENDING HOW CLOSE THOSE WARMER SSTS REACH. PREVIOUS FORECAST.................................................. AS OF 1300 PM FRIDAY...HAVE DECIDED NOT TO RAISE ANY HEADLINES FOR THE WATERS TONIGHT. DO EXPECT WINDS TO INCREASE FROM AROUND 10 KT BEING CURRENTLY REPORTED TO 10 TO 15 BY THE TIME THE SUN GOES DOWN. EXPECT TO SEE A FURTHER INCREASE OVERNIGHT...WITH MOST AREAS TOPPING OUT AROUND 15 KT...THOUGH SOUTHERN PORTIONS OF 250 AND EASTERN PORTIONS OF 252 MAY SEE SPEEDS 15 TO 20 KT. COLD FRONT RIGHT AROUND THE COAST BY THE END OF THE PERIOD...SO SOUTHWEST FLOW CAN BE EXPECTED ALL NIGHT. COOLER NEAR SHORE WATERS WILL HELP LIMIT MIXING AND WIND GUSTS BUT OUT CLOSER TO 40 NM...WHERE SSTS ARE A GOOD BIT WARMER...DO EXPECT TO SEE GOOD MIXING. DIRECTION SHOULD BE ALMOST PARALLEL TO THE COAST WHICH SHOULD KEEP HIGHER SEAS OUT OF MOST OF THE NEAR SHORE WATERS. LATEST SWAN AND WWIII SHOW A FEW ISOLATED 6 FT SEAS ACROSS EASTERN PORTIONS OF 252 AFTER MIDNIGHT BUT NOT ENOUGH TO WARRANT A HEADLINE AT THIS POINT. HOWEVER IT IS CLOSE AND A SLIGHT CHANGE TO THE FORECAST...WIND SPEED OR DIRECTION...COULD LEAD TO A LARGER AMOUNT OF 6 FT SEAS WITHIN 20 NM. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 230 PM FRIDAY...WESTERLY FLOW IN THE WAKE OF A COLD FRONT SATURDAY MORNING WILL RANGE FROM 15-20 KT AWAY FROM THE COAST AND 10-15 KT NEAR SHORE. THE OFFSHORE DIRECTION WILL LIMIT WAVE GROWTH NEARSHORE AS WELL...BUT SEAS AWAY FROM THE COAST SATURDAY WILL BE 3-5 FT (HIGHEST OFF CAPE FEAR). WINDS WILL DIMINISH SATURDAY NIGHT THEN BEGIN TO BACK TO THE SOUTHWEST SUNDAY MORNING. THE PRESSURE GRADIENT WILL INCREASE DURING SUNDAY AHEAD OF THE NEXT COLD FRONT THAT IS EXPECTED TO CROSS THE WATERS SUNDAY EVENING. COULD SEE A BRIEF PERIOD OF SMALL CRAFT CONDITIONS BY SUNDAY EVENING. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 230 PM FRIDAY...A STRONG ARCTIC COLD FRONT WILL MOVE ACROSS THE WATERS EARLY ON MONDAY...BRINGING STRONG NWLY WINDS AND HAZARDOUS SEAS TO THE COASTAL WATERS THROUGH THE LONG TERM. COLD SURGE LOOKS TO BE THE COLDEST ON TUESDAY MORNING...WITH NW WINDS IN THE 20 TO 30 KT RANGE...AND SEAS BUILDING TO 6 FT OR SO OVER THE OUTER PORTIONS OF OUR WATERS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...SRP NEAR TERM...DCH/III SHORT TERM...SRP LONG TERM...REK AVIATION...MAC
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
930 AM CST THU DEC 29 2011 .DISCUSSION...FORECAST CHALLENGE FOR UPDATE CONCERNS PCPN CHANCES/PHASE AND TEMPERATURES. CLEARING AND MODEST SNOW COVER ALLOWED TEMPERATURES TO DROP WELL IN THE SINGLE DIGITS ACROSS THE NORTHERN VALLEY THIS MORNING. CLOUDS WILL SPREAD ACROSS THE REGION TODAY HOWEVER WARM ADVECTION ACROSS FAR NORTH WILL BE LIMITED. FOR THIS WILL NEED TO LOWER MINIMUMS A BIT ACROSS THE FAR NORTH. PCPN INITIATION AND PHASE WILL BE BIG CHALLENGE LATE THIS AFTERNOON AND EVENING. WITH VERY LITTLE NEW DATA TO LOOK AT WILL NOT BE ALTERING POPS/WEATHER FOR UPDATE. RUC DOES INDICATE MOST PCPN MAY HOLD OFF TILL AFT 00Z HOWEVER NOT PICKING UP ON NARROW BAND ACROSS WESTERN ND. PREFER TO SEE NEW MODEL DATA BEFORE MAKING ANY CHANGES. && .AVIATION...VERY CHALLENGING FORECAST AND CONFIDENCE IS LOW. THERE WILL LIKELY BE A PERIOD OF VFR CIGS OR CLEAR SKIES DURING THE MORNING HOURS AND INTO THE AFTERNOON HOURS. HOWEVER...THERE IS A DEVELOPING AREA OF LOW CIGS NORTH OF THE INTERNATIONAL BORDER...AND NOT SURE WHAT IS GOING TO HAPPEN WITH THESE (COULD CONTINUE TO GROW SOUTHWARD). IFR/MVFR CIGS (VSBY WITH -SN) WILL APPROACH THE REGION DURING THE AFTERNOON HOURS AND CONTINUE INTO THE EVENING HOURS. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1016 AM EST THU DEC 29 2011 .SYNOPSIS... A PAIR OF ALBERTA CLIPPERS WILL MOVE ACROSS THE GREAT LAKES TODAY AND FRIDAY. A STRONG ARCTIC COLD FRONT IS LIKELY TO MOVE THROUGH THE STATE ON NEW YEARS DAY. GUSTY WINDS...BITTERLY COLD AIR AND LAKE EFFECT SNOW ARE EXPECTED AS THE COLD AIR RUSHES IN ACROSS THE LAKES. && .NEAR TERM /UNTIL 5 PM THIS AFTERNOON/... RETURN FLOW WEST OF THE BOUNDARY LAYER RIDGE AXIS IS TOUCHING OFF SOME VERY LIGHT PRECIP IN THE FORM OF SNOW OVER SOUTHWEST PA THIS MORNING. MOST HIGH RESOLUTION LCL MODELS AND OPERATIONAL GFS/NAM AND RUC HAVE NOT CAPTURED THIS...BUT LCL HRR AT LEAST HAS SOME QPF PAINTED OVER WESTERN PORTIONS OF THE LAUREL HIGHLANDS BETWEEN 14Z AND 16Z BEFORE DISSIPATING IT. TRACE AMOUNTS FROM FLURRIES SHOULD BE INCONSEQUENTIAL THIS MORNING...BUT DID ADD SLIGHT CHC POPS FOR THIS ALONG MY AREAS BORDERING KPBZ OVER THE LAUREL HIGHLANDS AND FURTHER NORTH INTO THE NORTH CENTRAL MOUNTAINS. AS UPPER SHORT WAVE DIVES DOWN OVER IA/WI EARLY THIS MORNING AND TOWARDS THE OHIO VALLEY THIS AFTERNOON...A MAIN AREA OF WARM ADVECTION PRECIPITATION WILL BREAK OUT ACROSS IL/OH AND CROSS INTO PA LATE THIS AFTERNOON. OTHER THAN FLURRIES THIS MORNING INTO THIS AFTERNOON SOUTHWEST...WEST AND NORTH...PRECIPITATION FROM THE MAIN WAVE WILL HOLD OFF UNTIL AFTER 22Z. HIGHS WILL BE A DEG OR TWO COOLER IN THE SE WITHOUT THE DOWNSLOPE AND LESS SUNSHINE TODAY VS WED. TEMPS IN THE N WILL BE 5-7F BETTER THAN WED DUE TO THE SRLY WIND/WAA. && .SHORT TERM /5 PM THIS AFTERNOON THROUGH SATURDAY/... WNW UPPER FLOW IS FAST WITH A 110KT JET STREAK FORCING THE LIFT TO IT/S LEFT EXIT REGION...AND WILL MOVE JUST TO THE SOUTH OF THE AREA BY MIDNIGHT. THE FLOW FLATTENS OUT A BIT AS THE MAIN WARM ADVECTION MOVES OVER OUR NRN ZONES AND NY STATE THIS EVENING AND OVERNIGHT. WILL RUN WITH ONLY HIGH CHC/LOW LIKELY POPS FOR THE NRN TIER TONIGHT...AS PRECIP MAY NOT BE HEAVY ENOUGH TO MAKE ACCUMS OF MORE THAN AN INCH THERE. POPS/CHC FOR SNOW FALL OFF PRETTY QUICKLY TO THE SOUTH OF ROUTE 6 AND ARE SMALL BY THE TIME YOU REACH I-80. TEMPS WILL PROBABLY FALL JUST A FEW DEGS FOR THE NIGHT WITH THE CLOUDS AND SOME S WIND. NEXT SHORT WAVE/CLIPPER WRAPS UP A BIT MORE THAN THE FIRST ONE...WITH A MORE COHERENT TROUGH BEGINNING TO FORM OVER THE UPPER MIDWEST ON FRI. SFC LOW DEEPENS NEAR 1000MB AS IT MOVES OVER LOWER MI AND THE LOWER LAKES. THIS STORM WILL SPREAD ADDITIONAL MOISTURE IN VERY QUICKLY ON FRIDAY AND ALLOW ONLY A BRIEF PERIOD OF FAIR WEATHER IN THE MORNING. HOWEVER...WITH WARM AIR OVERRUNNING THE COLD AIR AT THE SFC...SOUNDING PROFILES INDICATE AT LEAST SOME THREAT FOR PATCHY FREEZING DRIZZLE OR BRIEF FREEZING RAIN ACROSS MAINLY THE NORTHERN VALLEYS EARLY FRI MORNING. DO NOT EXPECT ENOUGH COVERAGE TO GARNER AN ADVISORY AT THIS TIME...BUT DID ADD THIS TO THE HWO. POPS WILL BE HIGHER FRI THAN THURS...BUT THE TEMPS WILL RISE ENOUGH AHEAD OF THIS PSEUDO CLIPPER TO MAKE MAINLY RAIN AFT 9 AM SOUTH OF I80. QPF WILL BE VERY LIGHT...THOUGH. NRN MTS COULD SEE MOSTLY SNOW BUT WAA WORKS TEMPS HIGHER THERE AS WELL...BUT THE COLD AIR WILL BE TOUGHER TO SCOUR OUT. WILL KEEP ANY MENTIONS OF ACCUMS IN THE NCENT COS. MAXES ON FRI WILL TRY TO GET INTO THE L50S IN THE S...BUT COULD STICK IN THE L-M 30S IN THE FAR NRN VALLEYS. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AFTER A BREAK ON SATURDAY...A STRONG ARCTIC COLD FRONT WILL BULLY ITS WAY THROUGH THE AREA DURING NEW YEARS DAY. THIS FEATURE WILL DEFINE THE LEADING WEDGE OF SOME MUCH COLDER AIR THAT WILL BRING THE PUFFY COATS BACK OUT OF THE CLOSET FOR AT LEAST A FEW DAYS. THE UPPER PATTERN WILL BECOME HIGHLY AMPLIFIED FOR THE FIRST FEW DAYS OF THE NEW YEAR WITH THE AXIS OF THE TROUGH SWINGING RIGHT THROUGH THE GREAT LAKES REGION. LONG TERM GUIDANCE COMING INTO LINE WITH SIMILAR IDEAS ON MUCH COLDER AIR FROM MONDAY THROUGH MID WEEK. -20C 850 TEMPS OVER THE STATE WOULD KEEP TEMPS AROUND THE 20 DEGREE MARK...GIVE OR TAKE A FEW DEPENDING ON CLOUD COVER. SAVE FOR ANY CLIPPER TYPE SYSTEMS THAT MAY ENTER THE PICTURE IN THIS DEEP TROUGH...LAKE EFFECT HOLD THE LIMITED CHANCE FOR SNOWFALL DURING THIS PERIOD. THE EURO MODEL STILL DEVELOPS A STORM SYSTEM AS THIS COLD POOL MOVES OVER THE GULF STREAM BUT DOES SO WELL EAST OF THE SOLUTION FROM 24 HOURS AGO...FAR OUT TO SEA. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... MVFR CIGS LINGERING IN HIGHER ELEVATIONS OF THE NW MTNS...WITH VFR ELSEWHERE AT 12Z. CIGS WILL LIFT TO VFR AREAWIDE BY 14-15Z AS WINDS TURN TO THE SOUTH AT AROUND 5 MPH FOR THE DAYLIGHT HOURS. SHORTWAVE/CLIPPER SLIDES IN FROM THE WEST EARLY THIS EVENING...SPREADING LOWER CIGS AND LIGHT SNOW BACK INTO MAINLY HIGHER TERRAIN OF THE WEST BY EARLY EVENING...WHILE REMAINDER OF THE AREA IS PRIMARILY VFR. INCREASING LOW LEVEL WINDS WHICH WILL LEAD TO MARGINAL WIND SHEAR AT BFD AND JST OVERNIGHT. A SLIGHTLY BETTER CHC OF SNOW OR RAIN SHOWERS FRI...AS A SECOND CLIPPER SYSTEM MOVES THROUGH. OUTLOOK... FRI...MVFR/IFR MAINLY WESTERN AREAS WITH RAIN/SNOW SHOWERS. SAT...MVFR NW MTNS. VFR ELSEWHERE. SUN...MAINLY VFR. SUN NIGHT-MON...MVFR POSS IN -SHSN. GUSTY WINDS. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO/DEVOIR SHORT TERM...DANGELO/DEVOIR LONG TERM...TYBURSKI AVIATION...RXR
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
910 PM CST FRI DEC 30 2011 .DISCUSSION...ISSUED AT 910 PM CST/ LITTLE CHANGE TO GOING FORECAST WITH STRATUS PERSISTING ACROSS THE NORTHERN AND EASTERN PORTIONS OF THE CWA THIS EVENING. DOES SHOW SOME SIGNS OF DISSIPATING ALONG THE WESTERN EDGE...BUT THINK THAT IT WILL HOLD THROUGH MUCH OF THE NIGHT...AND WITH ADDITIONAL MID AND HIGH CLOUDS STREAMING IN FROM THE WEST IT WILL REMAIN MOSTLY CLOUDY DURING THE NIGHTTIME HOURS. TEMPERATURES ARE PRETTY MUCH ON TRACK...AND DO THINK THEY WILL BEGIN TO RISE A BIT TOWARD TOMORROW MORNING WITH LOW LEVEL WARM AIR ADVECTION...SO INCORPORATED THAT INTO THE FORECAST. UPDATES OUT. && .PREV DISCUSSION.../ISSUED AT 315 PM CST/ WIDESPREAD STRATUS CONTINUES TO PERSIST ALONG AND EAST OF JAMES VALLEY AS OF 21Z WITH A GRADUAL CLEARING FROM THE WEST. THIS TREND WILL CONTINUE INTO THE EVENING...BUT WILL LIKELY STALL EAST OF INTERSTATE 29 AS WINDS BECOME LIGHT AND THEN SHIFT TO THE SOUTH. NAM CONTINUES TO SHOW BOUNDARY LAYER SATURATED THROUGH THE NIGHT...SO WILL LEAVE SKIES MOSTLY CLOUDY EAST...WITH INCREASING MID AND HIGH CLOUDS ACROSS THE WEST. TEMPERATURES WILL NOT FALL TOO MUCH TONIGHT WITH LOWS GENERALLY IN THE UPPER 20S TO MID 30S. STRONG FRONT WITH DECENT UPPER WAVE WILL PASS RATHER QUICKLY SATURDAY. STRENGTH OF WAVE CONTINUES TO MAKE A SOLID BAND OF RAIN OR SHOWERS A LIKELY EVENT AND WILL KEEP POPS IN THE HIGH CHANCE TO LIKELY CATEGORIES. HOWEVER WILL CUT BACK ON CHANCE MUCH SOONER THAN WE HAVE BEEN SINCE SUPPORT MOVES OUT SO QUICKLY...AND THERE DOES NOT APPEAR TO BE ENOUGH LOW LEVEL MOISTURE AND SUPPORT FOR LOW BASED LIGHT SNOW AND FLURRIES BEHIND FRONT. WILL CARRY A LITTLE CHANCE OF LIGHT RAIN AND SNOW FAR SOUTHEAST EARLY BUT NO ACCUMULATION THREAT. STRONG GRADIENT BEHIND FRONT WILL BRING WEST TO NORTHWEST WINDS UP VERY QUICKLY SATURDAY. HAVE DECIDED ON A WIND ADVISORY COMMENCING FROM WEST TO EAST MID MORNING TO MID AFTERNOON. WILL CARRY ADVISORY THROUGH SUNDAY AS GRADIENT REMAINS QUITE STRONG INTO THE START OF THE AFTERNOON THAT DAY. INITIAL BURST BEHIND FRONT COULD BRING WINDS CLOSE TO HIGH WIND CRITERIA FOR 2 TO 3 HOURS SATURDAY BUT EVEN THAT PEAK WILL BE BORDERLINE...SO DECIDED TO GO WITH THE ADVISORY. AFTER MIDDLE AND HIGH CLOUDS CLEAR SOMEWHAT LATE SATURDAY AND SATURDAY EVENING...SOME LOW CLOUDS LIKELY TO SPREAD INTO AT LEAST THE NORTHEAST HALF OF AREA WITH THE COLDER AIR LATE SATURDAY NIGHT AND SUNDAY. WITH THESE CLOUDS COULD CONCEIVABLY COME A FEW FLURRIES BUT WITH SUCH A PROGRESSIVE SYSTEM HAVE BEEN HAVING DOUBTS ABOUT EVEN THOSE FLAKES SO WILL LEAVE OUT FOR NOW. BASICALLY SUNDAY WILL BE A WINDY AND COLD DAY BUT OTHERWISE UNEVENTFUL...AND IT WILL TAKE THE WIND TO MAKE IT COLD GIVEN OUR COLD DAY WILL STILL BE SEVERAL DEGREES ABOVE NORMAL. MONDAY SHOULD BE DRY AND RELATIVELY CALM WITH DAYTIME TEMPERATURES COMPARABLE TO SUNDAY...NIGHTS BEFORE AND AFTER WILL BE OUR COLDEST. HOWEVER MONDAY WILL SEEM LIKE THE START OF ANOTHER WARMING TREND GIVEN THE MUCH LIGHTER WINDS. THE WARMING TREND WILL SHOW UP IN TEMPERATURES BY TUESDAY...MAKE IT THROUGH A DRY SHORT WAVE LATE TUESDAY AND TUESDAY NIGHT...AND PEAK ABOUT THURSDAY AS UPPER RIDGE BUILDS OVER AREA. NEXT WAVE MAKES IT COOLER OVER THE NEXT WEEKEND THEN IT LOOKS LIKE WE DO THE WARMUP THING AGAIN FURTHER BEYOND FORECAST PERIOD. / WILLIAMS && .AVIATION.../FOR THE 00Z TAF ISSUANCE/ IFR TO MVFR CEILINGS OVER TAF LOCATIONS WILL GRADUALLY AND I MEAN GRADUALLY SHIFT EAST PER RUC MOISTURE DATA. EXPECT VFR CONDITIONS AFTER 06Z. MAIN STORY WILL BE THE WINDS INCREASING AFTER FROPA ON SATURDAY. LOOKS LIKE RIGHT AROUND 17S FOR KHON...18Z KFSD...AND 19Z FOR KSUX. NORTHEAST WINDS TO INCREASE QUICKLY AFTER FROPA. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY FROM NOON SATURDAY TO 6 PM CST SUNDAY FOR IAZ001- 012-020-031. WIND ADVISORY FROM 3 PM SATURDAY TO 6 PM CST SUNDAY FOR IAZ002- 003-013-014-021-022-032. MN...WIND ADVISORY FROM NOON SATURDAY TO 6 PM CST SUNDAY FOR MNZ071- 097-098. WIND ADVISORY FROM 3 PM SATURDAY TO 6 PM CST SUNDAY FOR MNZ072- 080-081-089-090. NE...WIND ADVISORY FROM NOON SATURDAY TO 6 PM CST SUNDAY FOR NEZ013- 014. SD...WIND ADVISORY FROM NOON SATURDAY TO 6 PM CST SUNDAY FOR SDZ038>040-052>056-058>062-064>071. WIND ADVISORY FROM 9 AM SATURDAY TO 6 PM CST SUNDAY FOR SDZ050- 057-063. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
640 PM CST FRI DEC 30 2011 .DISCUSSION.../ISSUED AT 315 PM CST/ WIDESPREAD STRATUS CONTINUES TO PERSIST ALONG AND EAST OF JAMES VALLEY AS OF 21Z WITH A GRADUAL CLEARING FROM THE WEST. THIS TREND WILL CONTINUE INTO THE EVENING...BUT WILL LIKELY STALL EAST OF INTERSTATE 29 AS WINDS BECOME LIGHT AND THEN SHIFT TO THE SOUTH. NAM CONTINUES TO SHOW BOUNDARY LAYER SATURATED THROUGH THE NIGHT...SO WILL LEAVE SKIES MOSTLY CLOUDY EAST...WITH INCREASING MID AND HIGH CLOUDS ACROSS THE WEST. TEMPERATURES WILL NOT FALL TOO MUCH TONIGHT WITH LOWS GENERALLY IN THE UPPER 20S TO MID 30S. STRONG FRONT WITH DECENT UPPER WAVE WILL PASS RATHER QUICKLY SATURDAY. STRENGTH OF WAVE CONTINUES TO MAKE A SOLID BAND OF RAIN OR SHOWERS A LIKELY EVENT AND WILL KEEP POPS IN THE HIGH CHANCE TO LIKELY CATEGORIES. HOWEVER WILL CUT BACK ON CHANCE MUCH SOONER THAN WE HAVE BEEN SINCE SUPPORT MOVES OUT SO QUICKLY...AND THERE DOES NOT APPEAR TO BE ENOUGH LOW LEVEL MOISTURE AND SUPPORT FOR LOW BASED LIGHT SNOW AND FLURRIES BEHIND FRONT. WILL CARRY A LITTLE CHANCE OF LIGHT RAIN AND SNOW FAR SOUTHEAST EARLY BUT NO ACCUMULATION THREAT. STRONG GRADIENT BEHIND FRONT WILL BRING WEST TO NORTHWEST WINDS UP VERY QUICKLY SATURDAY. HAVE DECIDED ON A WIND ADVISORY COMMENCING FROM WEST TO EAST MID MORNING TO MID AFTERNOON. WILL CARRY ADVISORY THROUGH SUNDAY AS GRADIENT REMAINS QUITE STRONG INTO THE START OF THE AFTERNOON THAT DAY. INITIAL BURST BEHIND FRONT COULD BRING WINDS CLOSE TO HIGH WIND CRITERIA FOR 2 TO 3 HOURS SATURDAY BUT EVEN THAT PEAK WILL BE BORDERLINE...SO DECIDED TO GO WITH THE ADVISORY. AFTER MIDDLE AND HIGH CLOUDS CLEAR SOMEWHAT LATE SATURDAY AND SATURDAY EVENING...SOME LOW CLOUDS LIKELY TO SPREAD INTO AT LEAST THE NORTHEAST HALF OF AREA WITH THE COLDER AIR LATE SATURDAY NIGHT AND SUNDAY. WITH THESE CLOUDS COULD CONCEIVABLY COME A FEW FLURRIES BUT WITH SUCH A PROGRESSIVE SYSTEM HAVE BEEN HAVING DOUBTS ABOUT EVEN THOSE FLAKES SO WILL LEAVE OUT FOR NOW. BASICALLY SUNDAY WILL BE A WINDY AND COLD DAY BUT OTHERWISE UNEVENTFUL...AND IT WILL TAKE THE WIND TO MAKE IT COLD GIVEN OUR COLD DAY WILL STILL BE SEVERAL DEGREES ABOVE NORMAL. MONDAY SHOULD BE DRY AND RELATIVELY CALM WITH DAYTIME TEMPERATURES COMPARABLE TO SUNDAY...NIGHTS BEFORE AND AFTER WILL BE OUR COLDEST. HOWEVER MONDAY WILL SEEM LIKE THE START OF ANOTHER WARMING TREND GIVEN THE MUCH LIGHTER WINDS. THE WARMING TREND WILL SHOW UP IN TEMPERATURES BY TUESDAY...MAKE IT THROUGH A DRY SHORT WAVE LATE TUESDAY AND TUESDAY NIGHT...AND PEAK ABOUT THURSDAY AS UPPER RIDGE BUILDS OVER AREA. NEXT WAVE MAKES IT COOLER OVER THE NEXT WEEKEND THEN IT LOOKS LIKE WE DO THE WARMUP THING AGAIN FURTHER BEYOND FORECAST PERIOD. / WILLIAMS && .AVIATION.../FOR THE 00Z TAF ISSUANCE/ IFR TO MVFR CEILINGS OVER TAF LOCATIONS WILL GRADUALLY AND I MEAN GRADUALLY SHIFT EAST PER RUC MOISTURE DATA. EXPECT VFR CONDITIONS AFTER 06Z. MAIN STORY WILL BE THE WINDS INCREASING AFTER FROPA ON SATURDAY. LOOKS LIKE RIGHT AROUND 17S FOR KHON...18Z KFSD...AND 19Z FOR KSUX. NORTHEST WINDS TO INCREASE QUICKLY AFTER FROPA. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY FROM NOON SATURDAY TO 6 PM CST SUNDAY FOR IAZ001- 012-020-031. WIND ADVISORY FROM 3 PM SATURDAY TO 6 PM CST SUNDAY FOR IAZ002- 003-013-014-021-022-032. MN...WIND ADVISORY FROM NOON SATURDAY TO 6 PM CST SUNDAY FOR MNZ071- 097-098. WIND ADVISORY FROM 3 PM SATURDAY TO 6 PM CST SUNDAY FOR MNZ072- 080-081-089-090. NE...WIND ADVISORY FROM NOON SATURDAY TO 6 PM CST SUNDAY FOR NEZ013- 014. SD...WIND ADVISORY FROM NOON SATURDAY TO 6 PM CST SUNDAY FOR SDZ038>040-052>056-058>062-064>071. WIND ADVISORY FROM 9 AM SATURDAY TO 6 PM CST SUNDAY FOR SDZ050- 057-063. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
937 AM EST THU DEC 29 2011 .DISCUSSION... THE POSITION OF THE JET STREAM OVER THE UPPER MS VALLEY TO OHIO VALLEY IS BRINGING CONSIDERABLY CLOUDINESS TO NORTHERN PORTIONS OF THE AREA THIS MORNING. RUC AND NAM SHOW DECREASING CLOUD COVER THROUGH THE AFTERNOON...BUT THE MORNING CLOUDS ARE KEEPING TEMPERATURES LOWER THAN FORECAST SO FAR. WILL ISSUE AN UPDATE TO ADJUST TEMPERATURES DOWNWARD IN THE NORTH...AND INCREASE CLOUD COVER AS WELL. && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DGS
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
335 AM CST SAT DEC 31 2011 .SYNOPSIS... 06Z SFC ANALYSIS HAS A LOW IN NORTHWEST SOUTH DAKOTA WITH A WARM FRONT RUNNING SOUTHEAST TO NEAR KSUX. A TROF RAN FROM A LOW IN SOUTHERN LAKE HURON INTO CENTRAL ILLINOIS AND THEN NORTHWEST INTO SOUTHEAST MINNESOTA. DEW POINTS WERE GENERALLY IN THE 20S AND 30S ACROSS THE MIDWEST. SATELLITE HAS AN AREA OF LOW CLOUDS ACROSS EASTERN IOWA AND MOST OF ILLINOIS TRAPPED UNDER AN INVERSION WITH MID AND HIGH CLOUDS MOVING EAST FROM THE ROCKIES. && .SHORT TERM...TODAY AND TONIGHT THERE ARE MANY CONCERNS OVER THE NEXT 36 HRS. IN THE IMMEDIATE SHORT TERM ARE THE CLOUDS AND FOG POTENTIAL. THE LOW CLOUDS ACROSS THE AREA ARE TRAPPED UNDER AN INVERSION. RUC TRENDS MAINTAIN THE INVERSION FOR MOST OF THE MORNING BEFORE BREAKING IT UP AROUND MID DAY. IF CORRECT...THEN THE CLOUD COVER WILL HOLD DOWN TEMPERATURES TODAY. AS FOR THE FOG...IT IS ONLY PATCHY IN SPOTS RIGHT NOW AND IT WILL BE MONITORED. AN SPS MAY BE ISSUED FOR THOSE AREAS WHERE THE FOG IS LOCALLY DENSE. THE CLOUDS SHOULD BREAK UP DURING THE DAY RESULTING IN A QUIET AND MILD DAY FOR THE LAST DAY OF DECEMBER. ATTENTION THEN TURNS TO THE APPROACHING SYSTEM FOR TONIGHT. FIRST...ALL MODELS INITIALIZED TOO MOIST IN THE LOWER LEVELS WHEN COMPARED AGAINST THE 00Z UA DATA. THIS MOIST BIAS IS LIKELY RESULTING IN THE MODELS PUTTING OUT TOO MUCH QPF FOR TONIGHT. BASED ON THE OVERALL FORCING AND CONDENSATION PRESSURE DEFICITS THE EARLY EVENING HOURS WILL BE DRY WITH THE PRECIPITATION REMAINING IN CENTRAL IOWA. BETWEEN 9 PM AND MIDNIGHT...RAIN WILL DEVELOP OR MOVE INTO THE WESTERN CWFA AS CONTINUED WAA OCCURS AND TEMPERATURES ALOFT REMAIN ABOVE 0 CELSIUS. AFTER MIDNIGHT...STRONG CAA OCCURS AS THE FRONT MOVES THROUGH. FCST SOUNDINGS QUICKLY DROP BELOW FREEZING AND WBZ TEMPERATURES DROP BELOW FREEZING AS WELL. THUS MIDNIGHT TO 3 AM WILL SEE A FAIRLY RAPID TRANSITION FROM RAIN TO SNOW WITH A MIX FOR A FEW HOURS. AFTER 3 AM...CAA CONTINUES AND SNOW SHOULD BE SEEN ACROSS THE ENTIRE AREA. THIS EVENT WILL ONLY LAST ABOUT 6-7 HRS IN ANY ONE LOCATION ONCE IT BEGINS. SINCE ABOUT HALF OF THE EVENT WILL BE RAIN...THE SNOW AMOUNTS WILL BE QUITE LIGHT AND SHOULD BE AT WORST ONE HALF INCH. MOST AREAS WILL ONLY SEE A DUSTING OF ACCUMULATION. THE OTHER CONCERN IS THE WIND. THE STRONG CAA COMBINED WITH A STRONG PRESSURE GRADIENT WILL RESULT IN VERY STRONG WINDS. WINDS ARE PROGGED TO BE NEAR 50 KNOTS STARTING JUST ABOVE 925 MB. HOWEVER...LOW LEVEL LAPSE RATES ARE NOT OVERLY STEEP SO THE HIGHER MOMENTUM AIR ALOFT MAY HAVE TROUBLE MIXING DOWN TO THE SFC. SINCE A WIND ADVISORY IS ALREADY OUT...IT WILL BE CONTINUED. HOWEVER...THE START TIME WILL BE PUSHED BACK TO MIDNIGHT AND THE AREAL COVERAGE WILL BE EXPANDED AS WELL. ..08.. .LONG TERM...SUNDAY THROUGH FRIDAY... SUNDAY WILL BE VERY WINDY...SUNDAY NIGHT THROUGH MONDAY EVENING WILL BE RATHER WINDY TOO. MOST OTHER QUESTIONS ARE CONCERNED WITH CLOUD COVER AND THE AFFECT ON TEMPERATURES THROUGH THE EARLY WEEK. OTHERWISE THE EXTENDED FORECAST GENERALLY REMAINS UNCHANGED AS WE SEE ANOTHER SEVERAL DAYS OF VERY MILD WEATHER IN THE WEDNESDAY THROUGH FRIDAY PERIOD. SUNDAY...WE WILL BEGIN THE DAY WITH STRONG CAA AND STRATUS LIKELY SPREADING OVER THE AREA. ANY MOISTURE SEEMS VERY THIN...THUS FLURRIES ARE NOT INCLUDED YET. EARLY DAY WILL BE WINDY...WITH SOME WIND GUSTS BEFORE 9 AM REACHING UP AROUND 40 MPH IN THE NORTHWEST...AND 35 MPH ELSEWHERE. BETWEEN 9 AM AND SUNSET...WE SHOULD SEE WIND ADVISORY LEVELS IN MOST OF THE CWA. AT THIS POINT...OUR COUNTIES ALONG AND WEST OF THE MISSISSIPPI RIVER LOOK VERY LIKELY TO SEE WIND GUSTS OVER 45 MPH AT TIMES MID DAY SUNDAY. SOME GUSTS TO AROUND 50 MPH ARE POSSIBLE SUNDAY NOON THROUGH 2 PM SUNDAY. WITH THE CERTAINTY OF WIND CRITERIA OVER THE WESTERN HALF OF THE CWA...WILL EXTEND THE ADVISORY FURTHER EAST. THOUGH THE COUNTIES JUST EAST WILL POSSIBLY HIT CRITERIA AS WELL...THEY APPEAR MORE MARGINAL AT THIS TIME...AND WITH ONSET CLOSER TO 12Z SUNDAY IN THOSE LOCATIONS...WILL KEEP THEM OUT OF THE ADVISORY. SUNDAY NIGHT...WINDS MAY REMAIN NEAR ADVISORY LEVELS THROUGH THE EVENING...AND CURRENT HEADLINES KEEP OUR NORTHWEST COUNTIES IN ONE THROUGH 06Z MONDAY. TEMPERATURES WILL DROP INTO THE TEENS SUNDAY EVENING...AND MAY FALL TO THE RANGE OF 10 TO 15 BY MONDAY MORNING. WIND CHILLS IN THE TEENS SUNDAY WILL DROP TO THE -8 TO +5 RANGE BY MONDAY MORNING. 2012 WILL CERTAINLY ENTER WITH A GOOD DOSE OF WINTER TEMPERATURES...THIS COLD SNAP WILL BE OVER QUITE QUICKLY. AFTER A COLD NIGHT MONDAY NIGHT...TUESDAY WILL BEGIN OUR NEXT WARM UP...AS ZONAL FLOW DEVELOPS ALOFT. BY THURSDAY AND FRIDAY...TEMPERATURES COULD EASILY REACH THE 50S IN MANY PARTS OF THE CWA. ..ERVIN.. && .AVIATION... /ISSUED 1138 PM CST FRI DEC 30 2011/ STRATUS REMAINS OVER THE AREA WITH SOME HOLES OPENING UP IN THE CLOUDS NEAR THE MISSISSIPPI RIVER. EXPECT THESE HOLES TO FILL BACK IN WITH IFR/MVFR CIGS/VSBYS REMAINING OVER THE AREA UNTIL THE BACK EDGE MOVES THROUGH BETWEEN 09Z AND 12Z. A FEW SPRINKLES OR FLURRIES WILL BE POSSIBLE FOR A FEW MORE HOURS AFTER MIDNIGHT NEAR THE RIVER. EXPECT CONDITIONS TO IMPROVE TO VFR AT ALL SITES BY MID MORNING SATURDAY WITH SOUTH WINDS INCREASING THE 15 TO 20KTS WITH GUSTS OVER 25KTS MUCH OF THE DAY. WINDS TO TURN TO THE WEST DURING THE EVENING WITH MVFR/LOWER VFR CIGS SPREADING OVER THE AREA. SOME LIGHT RAIN OR LIGHT SNOW MAY MOVE INTO THE KCID/KDBQ AREAS AFTER 03Z. ..DLF.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR BENTON-CEDAR-CLINTON-DES MOINES-HENRY IA-IOWA-JACKSON- JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-MUSCATINE- SCOTT-VAN BUREN-WASHINGTON. WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR BUCHANAN-DELAWARE-DUBUQUE. IL...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR JO DAVIESS-MERCER-ROCK ISLAND. MO...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR CLARK- SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1233 AM EST SAT DEC 31 2011 .SYNOPSIS... LOW PRESSURE OVER THE GREAT LAKES WILL WEAKEN TONIGHT WITH REDEVELOPMENT OFF OF CAPE COD ON SATURDAY. THIS NEW LOW PRESSURE WILL TRACK EASTWARD THROUGH THE GULF OF MAINE AND THEN SOUTH OF NOVA SCOTIA BY SATURDAY EVENING. A HIGH PRESSURE RIDGE WILL BUILD ACROSS THE REGION ON SUNDAY. && .NEAR TERM /THROUGH SATURDAY/... UPDATE: TEMPERATURES NEEDED ADJUSTMENT TO RAISE THEM PER LATEST OBS. LAMP GUIDANCE DOING WELL W/THIS ATTM. INITIAL AREA OF LIGHT SNOW/FLURRIES LIFTING ACROSS NORTHERN MAINE AND THEN SECOND AREA STARTING TO SHOW SIGNS OVER NORTHERN NH AND SOUTHERN ME. POPS WERE ADJUSTED FOR THIS SECOND SURGE TO SLOW DOWN TIMING AND MOVE CONCENTRATED AREA FURTHER W. REST OF THE FCST LOOKS OK. PREV DISC: SHORTWAVE TROUGH FLATTENING UPPER RIDGE ACROSS THE STATE IS PRODUCING AN AREA OF LIGHT SNOW SHOWERS ACROSS WESTERN MAINE THIS AFTERNOON. HRRR MODEL INDICATES AS THIS SHORTWAVE TROUGH MOVES ACROSS DOWNEAST LATE THIS AFTERNOON INTO THIS EVENING, A PERIOD OF SNOW SHOWERS CAN BE EXPECTED WITH ANY ACCUMULATION LESS THAN AN INCH. MODELS IN GOOD AGREEMENT WITH LOW PRESSURE OVER THE GREAT LAKES FILLING TONIGHT WITH REDEVELOPMENT JUST EAST OF CAPE COD BY SATURDAY AFTERNOON. THE LOW PRESSURE WILL THEN TRACK EASTWARD AND MOVE SOUTH OF NOVA SCOTIA BY SATURDAY NIGHT. WITH HIGH PRESSURE EAST OF THE REGION INSTEAD OF NORTH OF THE STATE, WARM ATLANTIC AIR IN THE LOWER LEVELS WILL BE ALLOWED TO FLOW NORTHWARD ACROSS THE FORECAST AREA PRODUCING ANOTHER WINTRY MIX FOR THE REGION. CRITICAL THICKNESS NOW INDICATING MORE MIX THAN SNOW SO HAVE REDUCE SNOW ACCUMULATION ACROSS CENTRAL AND NORTHERN SECTIONS BY AROUND AN INCH AND INCREASE ICE ACCUMULATIONS BY A TENTH OF AN INCH ACROSS CENTRAL PORTIONS. AT THIS TIME, EXPECT THE AXIS OF HEAVIEST ICE TO OCCUR 30 MILES ON EITHER SIDE OF A LINE FROM GREENVILLE TO HOULTON WHERE UP TO A QUARTER OF AN INCH MAY ACCUMULATE. MODELS ALSO INDICATING TEMPERATURES WILL BE SLOW TO RISE ACROSS DOWNEAST SO WILL EXTEND ADVISORY FROM 7 AM TO NOONTIME SATURDAY. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... THINGS WILL BE WINDING DOWN SATURDAY NIGHT AS THE LOW MOVES OUT OF THE GULF OF MAINE AND SOUTH OF NOVA SCOTIA. THERE WILL BE SOME LINGERING FREEZING RAIN IN NORTHERN SECTIONS DURING THE EVENING BUT COLDER AIR WRAPPING AROUND THE DEPARTING SYSTEM WILL CHANGE THE PRECIPITATION TO ALL SNOW FROM NORTH TO SOUTH THROUGH THE NIGHT. SNOWFALL AMOUNTS WILL BE LIGHT...GENERALLY A DUSTING TO AROUND HALF AN INCH WITH ANOTHER TRACE OF ICE ACCUMULATION. HIGH PRESSURE WILL BRIEFLY BUILD IN SUNDAY BEFORE ANOTHER LOW PRESSURE SYSTEM MOVES BY TO OUR NORTH SUNDAY NIGHT AND MONDAY. THIS WILL BRING ANOTHER ROUND OF SNOW AND RAIN TO THE REGION. THE RAIN/SNOW LINE WILL BE SOUTH OF HOULTON AND MILLINOCKET WITH THE IMMEDIATE COAST ALL RAIN BY MONDAY AFTERNOON. EXPECT TEMPERATURES TO REACH INTO THE 30S DUE TO INCREASING SOUTH FLOW AHEAD OF THE SYSTEM...BUT A STRONG COLD FRONT WILL PUSH THROUGH THE REGION DURING THE DAY MONDAY USHERING IN MUCH COLDER AIR FOR THE WORK WEEK.&& && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... COLDER AIR WILL FILTER INTO THE REGION FOR MONDAY NIGHT AND TUESDAY ACCOMPANIED BY MAINLY CLOUDY SKIES ALONG WITH SCATTERED SNOW SHOWERS AND FLURRIES DUE TO AN UPPER LEVEL TROUGH LINGERING IN THE REGION. PRECIPITATION WILL BE CONFINED MAINLY TO NORTHERN AREAS WHERE A FEW HEAVIER SNOW SHOWERS WILL BE POSSIBLE DUE TO BANDS SETTING UP OFF THE ST. LAWRENCE. HIGH PRESSURE WILL BRIEFLY MOVE IN FOR WEDNESDAY RESULTING IN MAINLY SUNNY SKIES AND DRY CONDITIONS REGION WIDE. HOWEVER TEMPERATURES WILL STRUGGLE TO MAKE IT OUT OF THE LOW TO MID TEENS NORTH WITH HIGHS DOWNEAST REACHING THE LOW 20S. HIGH PRESSURE WILL SLIDE OFF TO THE EAST THURSDAY AS THE NEXT UPPER LEVEL TROUGH APPROACHES THE EAST COAST RESULTING IN INCREASING CLOUDS ALONG WITH THE SLIGHT CHANCE FOR A FEW FLURRIES FOR THE END OF THE WEEK. AT THIS POINT ANY SURFACE CYCLOGENESIS ASSOCIATED WITH THIS TROUGH LOOKS TO TAKE PLACE TOO FAR SOUTH AND EAST TO AFFECT THE REGION WITH SIGNIFICANT PRECIPITATION. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: VFR CONDITIONS TONIGHT WILL LOWER TO IFR IN A WINTRY MIX ON SATURDAY. THERE MAY BE A BRIEF PERIOD OF MVFR/IFR IN SNOW AT KBGR AND KBHB BETWEEN 21Z-02Z AS AN AREA OF SNOW SHOWERS MOVES ACROSS DOWNEAST. SHORT TERM: IFR CONDITIONS IN SNOW AND RAIN THROUGH THE FIRST PART OF SATURDAY NIGHT. PERIODS OF FREEZING RAIN WILL BE POSSIBLE THROUGH 06Z SUNDAY. CONDITIONS WILL GRADUALLY IMPROVE AFTER MIDNIGHT AND EXPECT ALL TERMINALS TO BE VFR BY 12Z SUNDAY. A RETURN TO IFR COMES SUNDAY NIGHT AS SNOW SPREADS OVER THE REGION. IFR IN SNOW AND RAIN SUNDAY NIGHT AND MONDAY. BRIEF PERIODS OF MVFR/IFR CONDITIONS WILL BE POSSIBLE MONDAY NIGHT AND TUESDAY FOR THE NORTHERN SITES DUE TO LINGERING SCATTERED SNOW SHOWERS AND FLURRIES WITH VFR CONDITIONS PREDOMINATING FOR KBGR AND KBHB. HIGH PRESSURE WILL BUILD IN WEDNESDAY WITH VFR CONDITIONS EXPECTED FOR ALL SITES. && .MARINE... NEAR TERM: AS LOW PRESSURE MOVES THROUGH THE GULF OF MAINE, MINIMAL SCA CONDITIONS POSSIBLE OVER OUR OUTER WATERS ON SATURDAY. SHORT TERM: NO HEADLINES ANTICIPATED SATURDAY NIGHT AND SUNDAY AS HIGH PRESSURE BRIEFLY BUILDS OVER THE WATERS. LOW PRESSURE WILL MOVE BY TO THE NORTH SUNDAY NIGHT AND MONDAY SO EXPECT WINDS AND SEAS TO INCREASE THROUGH THE PERIOD. A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED WITH GALES A POSSIBILITY. WINDS AND SEAS WILL CONTINUE TO BE AT SCA LEVELS FOR MONDAY NIGHT AND TUESDAY. SEAS WILL DIMINISH WEDNESDAY BUT WINDS WILL CONTINUE TO REMAIN NEAR SCA LEVELS BEFORE DIMINISHING FOR WEDNESDAY NIGHT AND THURSDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MEZ001>006-010. WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MEZ011- 015>017-031-032. MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST THIS EVENING FOR ANZ050-051. && $$ NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1258 AM EST SAT DEC 31 2011 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OFF TO THE SOUTHEAST TONIGHT AS A COLD FRONT APPROACHES FROM THE WEST. THE FRONT PASSES THROUGH SATURDAY MORNING...WITH HIGH PRESSURE BUILDING IN FOR THE REMAINDER OF THE DAY AND NIGHT. A MUCH STRONGER COLD FRONT CROSSES THE REGION BY SUNDAY NIGHT...WITH AN ARCTIC AIRMASS OVERSPREADING THE MID ATLANTIC FOR THE UPCOMING WORK WEEK. && .NEAR TERM /THROUGH TODAY/... CHANCES FOR PRECIP OVERNIGHT LOOKING MORE AND MORE LIMITED. UPSTREAM RADAR OVER KY AND TN STILL SHOWS A LACK OF DEVELOPMENT AND THE TREND WITH THE RUC HAS BEEN TO REDUCE THE COVERAGE OF PRECIP OVERNIGHT. STILL THINK THERE WILL BE A PERIOD OF BRIEF SCATTERED AND PATCHY LIGHT RAIN BUT SOME AREAS ESPECIALLY WEST OF RIC MAY NOT SEE ANY PRECIP AT ALL. THOSE AREAS FROM RIC EAST WHICH MIGHT SEE A FEW SHOWERS WILL ONLY EXPERIENCE A BRIEF SHOWER. WILL KEEP VERY LOW CHANCE POPS IN THE FORECAST BUT FOR ANY GIVEN AREA THE CHANCE FOR PRECIP WILL BE NO MORE THAN JUST A FEW HOURS FROM 06Z-12Z. DESPITE A LACK OF DEEP MOISTURE THE DYNAMICS WILL BE STRONG ENOUGH TO SQUEEZE OUT A FEW SHOWERS. IR SATELLITE SHOWS CONTINUED ENHANCEMENT IN THE CLOUD TOPS NORTH AND WEST OF THE CWA. THE WRF NMM AND ARW ARE BOTH LESS EXCITED ABOUT PRECIPITATION OVERNIGHT BUT STILL BRING A FEW BRIEF WIDELY SCATTERED SHOWERS ACROSS THE AREA. WITH THIS IN MIND WILL KEEP THE SMALL CHANCE POPS (25-30%). OVERALL PRECIP IN ANY GIVEN LOCATION WILL NOT LAST VERY LONG AND COVERAGE COULD BE RATHER LIMITED. RAINFALL WILL LIKELY JUST BE ENOUGH TO WET THE GROUND BUT LESS THAN A TENTH OF AN INCH ON AVERAGE. SOME RAIN MAY LINGER PAST 12Z OVER EXTREME SE VA/NE NC AND THE EASTERN SHORE. PRECIP WILL SHUT OFF QUICKLY FOLLOWING THE PASSAGE OF THE MID-LEVEL TROUGH AXIS. TEMPS THIS EVENING WILL BE TEMPERED BY INCREASING CLOUDS FROM THE WEST. LOWS WILL STABILIZE IN THE IN THE UPR 40S ON AVERAGE BUT WITH DEWPOINTS IN THE MID TO UPPER 30S SOME EVAP COOLING IN AREAS OF SHOWERS COULD PUSH SOME LOCAL READINGS INTO THE MID 40S. FOR SATURDAY MIXING IN THE WESTERLY FLOW BEHIND THE DEPARTING TROUGH AXIS WILL WARM TEMPS INTO THE UPPER 50S TO MID 60S UNDER MOSTLY SUNNY SKIES. WINDS WILL PICK UP SOME BY LATE MORNING RESULTING IN WEST WINDS AROUND 10 TO 15 MPH WITH A FEW GUSTS TO NEAR 20 MPH. && .SHORT TERM /TONIGHT THROUGH MONDAY/... CLR OR MOSTLY CLR SAT NGT WITH LIGHT WINDS ALLOWING TEMPS TO FALL INTO THE MID TO UPR 30S. WARM AGAIN ON SUN AHEAD OF AN APPROACHING STRONG COLD FRONT. WITH DEEP SW FLOW...EXPECT HIGHS IN THE LWR TO MID 60S OVR MOST OF THE AREA. THE COLD FROPA OCCURS SUN AFTN/EVNG...BUT WILL MAINTAIN A DRY FORECAST DUE TO A LACK OF MOISTURE (POPS CAPPED AT 14%). SKY COVER MAY NOT BE GREATER THAN PRTLY CLDY. ARTIC AIRMASS BEGINS OVERSPREADING THE MID ATLANTIC EARLY IN THE WORK WEEK BEHIND THE COLD FRONT AS A POLAR VORTEX DROPS INTO SE CANADA. TEMPS ON MON WILL ONLY MAX OUT IN THE LOW TO MID 40S...WITH WIND CHILLS IN THE MID 30S. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... FIRST ARCTIC AIRMASS OF THE SEASON COMES IN MONDAY NIGHT AND CONTINUES THROUGH WEDNESDAY. TIGHTENING PRES GRADIENT ALONG WITH WEAK S/W ENERGY WILL MAKE TUESDAY A COLD / BLUSTERY DAY WITH TEMPS HARD PRESSED TO GET MUCH ABOVE THE L-M30S ALONG WITH GUSTY NW WINDS OF 25-35 MPH. WIND CHILLS BETWEEN 15-25 DEGREES. GIVEN PROGGED H85 TMPS OF ARND -15C COMBINED WITH WATER TEMPS ARND 9C TUES...I WAS SOMEWHAT CONCERNED ABOUT THE PSBLTY OF BAY EFFECT SNOW SHOWERS DVLPNG. HOWEVER...WINDS WILL BE MORE NW THAN DUE N ALONG WITH DP TEMPS BETWEEN 0-5 ABOVE W OF BAY...ARND 10 NEAR THE WATER. EXPECT MORE BAY EFFECT STREAMER SC CLOUDS THAN PCPN. STILL CAN`T RULE OUT A FLURRY OR TWO ALONG THE COAST TUE AS MOISTURE FIELDS BEGIN TO EXPAND IN RESPONSE TO DVLPNG COASTAL LOW. 12Z EURO MORE ROBUST AND CLOSER TO THE COAST WITH SAID COASTAL LOW THAN GFS. AT MOST...SOME FLURRIES OR SNOW SHWRS CUD ROTATE W TOWARD COASTAL AREAS TUE NIGHT...BUT CONFIDENCE NOT HIGH ENUF ATTM TO LEAN IN THAT DIRECTION. INSTEAD...EXPECT WINDS TO SLOWLY DIMINISH TUE NITE ALONG WITH PT CLDY SKIES. TEMPS DROP INTO THE TEENS MOST AREAS...NR 20 ALONG THE SE COAST. RIDGE AXIS STILL WEST OF FA WED SO IT WILL CONT DRY / COLD BUT WITH LESS WIND. HIGHS IN THE M-U30S. LOWS WED NITE L-M20S. WITH A DOMINATE NORTHERN JET STREAM AND NO DOWNSTREAM BLOCKING... NEXT S/W CLIPPER PROGGED TO TRACK NORTH OF FA THU. MAY SEE SOME CLOUDS WITH THIS FEATURE BUT NO PRECIP ATTM. SLOW WARMING TREND AS WINDS SHIFT INTO THE SW. HIGHS THU L-M40S AND M-U40S FRI. LOWS THU NITE IN THE M20S-L30S. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WEAK LOW PRESSURE WILL PASS TO THE NORTH OF THE FORECAST AREA, WITH THE ASSOCIATED WEAK COLD FRONT CROSSING THROUGH THE AREA FROM THE WEST LATER THIS MORNING. EXPECT CEILINGS TO REMAIN IN VFR RANGE THROUGH THIS PERIOD, BUT WILL LOWER THROUGH 14Z OR SO TO AROUND 4-5K FT THROUGHOUT THE AREA. LOW LEVEL MOISTURE CONINUES TO LOOK QUITE MEAGER. HV ACCORDINGLY OPTED TO REMOVE PREDOMINATE RAIN GROUP FROM TAF, SAVE FOR A VCSH MENTION AT KSBY FOR SOME POSSIBLE -SHRAS/SPRINKLES THROUGH MID MORNING. 5-10KT S/SW WINDS WILL PREVAIL BEFORE FRONTAL PASSAGE, VEERING TO THE WEST WINDS AND GUSTING TO AROUND 20KT AFTER PASSAGE. CEILINGS ARE EXPECTED TO IMPROVE QUICKLY BEHIND THE FRONTAL PASSAGE...WITH CLR CONDITIONS EXPECTED BY SAT NIGHT/SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. OUTLOOK: ANOTHER COLD FRONT/WIND SHIFT APPROACHES THE AREA SUN NIGHT...WITH GUSTY NW WINDS EXPECTED IN THE WAKE OF A STRONG COLD FRONTAL PASSAGE MONDAY INTO TUESDAY AS MARKEDLY COLDER AIR PUSHES ACROSS THE REGION. && .MARINE... TRICKY FORECAST TONIGHT/SAT AS SHORT RANGE MODELS HINT THAT S-SW WINDS WILL APPROACH MINIMAL SCA LEVELS OVER THE CHES BAY. WILL FORECAST A SOLID 15 KTS WITH THIS PACKAGE WITH GUSTS AROUND 20 KT. OTW...SW-W FLOW CONTINUES THROUGH THE WKEND...AS HIGH PRESSURE MOVES OFF THE COAST. NEXT CHC FOR SCA CONDITIONS COMES SUNDAY NIGHT AND MONDAY AS A COLD FRONT PROGGED TO MOVE OFF THE COAST. BEYOND THAT...OFFSHORE LOW DEEPENS MONDAY NIGHT AND TUESDAY BEFORE LIFTING NE AND AWAY FROM REGION BY MID WEEK. LATEST DATA SUPPORTS A DEEP MIXING LAYER AS ARCTIC AIRMASS PRODUCES STRONG CAA ACROSS ENTIRE MARINE AREA. AT THIS POINT...CONFIDENCE IS GROWING FOR GALE FORCE WINDS / GUSTS MONDAY NIGHT AND TUESDAY. STAY TUNED. && .CLIMATE... VERY WARM DECEMBER TO END A VERY WARM YEAR FOR 2011: BASED ON PREDICTED TEMPERATURES FOR THE REST OF THE MONTH: RICHMOND...WILL LIKELY END UP AS 8TH WARMEST DECEMBER ON RECORD...AND THE 4TH WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 7TH COLDEST AND ABOUT 13 F COLDER THAN THIS DEC! NORFOLK...WILL LIKELY END UP AS THE 6TH OR 7TH WARMEST DECEMBER ON RECORD...AND 3RD WARMEST YEAR ON RECORD. *COMPARE THIS TO LAST DEC WHICH WAS THE 4TH COLDEST AND ABOUT 15 F COLDER THAN THIS DEC! MORE DETAILS AS WE END THE YR. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ANZ630>632-634. && $$ SYNOPSIS...MAS NEAR TERM...JAO SHORT TERM...MAS LONG TERM...MPR AVIATION...MAM MARINE...MPR CLIMATE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1240 AM EST SAT DEC 31 2011 .SYNOPSIS... A COLD FRONT WILL PUSH OFF THE COAST THIS MORNING...HOWEVER NO SIGNIFICANT COOLING IS EXPECTED IN THE WAKE OF THIS FRONT. A STRONGER COLD FRONT PASSING THROUGH SUNDAY EVENING WILL BE FOLLOWED BY THE COLDEST AIR-MASS OF THE SEASON. COLD AIR WILL PERSIST THROUGH MID-WEEK BEFORE A WARMING TREND COMMENCES. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 915 PM FRIDAY...LATEST NAM MODEL INDICATES 1K TO 8H THICKNESSES TO INCREASE AHEAD OF THE COLD FRONT DURING TONIGHT. MINS HAVE BEEN ADJUSTED TO OR SLIGHTLY HIGHER THAN MODEL MOS GUIDANCE. LATEST HRRR AND NAM INDICATES NO PCPN ACROSS THE ILM INLAND LOCALES...HOWEVER THEY WANT TO DEVELOP PCPN IMMEDIATELY ALONG THE COAST...MAINLY ALONG THE PRE-FRONTAL TROF DURING THE PRE-DAWN HRS OF SATURDAY. UP TO ONE TENTH OF AN INCH IS SHOWN BY HRRR. AGAIN WITH LIMITED MOISTURE THRU THE ATM COLUMN...EXCEPT BETWEEN MIDNIGHT AND 7AM WHEN MOISTURE ASSOCIATED WITH THE PRE-FRONTAL TROF AND THE FRONT ITSELF TRACKS ACROSS THE FA. UVVS FROM THE DYNAMICS FROM THE UPPER VORT ASSOCIATED WITH THE PROGRESSIVE 5H S/W TROF...TO AID IN THE DEVELOPMENT OF ISOLATED -SHRA AHEAD OF THE PRE-FRONT TROF AND THE FRONT ITSELF OVER LAND AREAS LATER TONIGHT...NOT ENOUGH TO WARRANT A POP THOUGH. THE MAJORITY OF THE PCPN TO DEVELOP ALONG THE ADJACENT ATL WATERS...BASICALLY ALONG THE WEST WALL OF THE GULF STREAM TOWARDS DAYBREAK WHERE OCEAN SFC BASED PARAMETERS AID SHOWER DEVELOPMENT. WITH ALL OF THIS SAID ALONG WITH THE LATEST MOSAIC 88DS AND SATELLITE INFO INJECTED INTO THE EQUATION...HAVE CONTINUED TO KEEP THE ILM CWA PCPN-LESS. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 230 PM FRIDAY...PROGRESSIVE PATTERN WILL PERSIST THROUGH THE SHORT TERM PERIOD. THE INITIAL SHORTWAVE AND SURFACE COLD FRONT WILL SHIFT OFF THE EAST COAST EARLY SATURDAY FOLLOWED BY WEAK RIDGING ALOFT SATURDAY NIGHT INTO SUNDAY MORNING. A DEEPER TROUGH WILL EVOLVE OVER THE EASTERN STATES BY SUNDAY NIGHT. THE SECOND STRONGER COLD FRONT PASSING THROUGH SUNDAY EVENING WILL BE FOLLOWED BY AN ARCTIC AIR-MASS. OTHER THAN SOME CLOUDS SATURDAY MORNING NOT MUCH MOISTURE FOR EITHER OF THE FRONTS TO TAP INTO THUS NO POPS REQUIRED. MAX TEMPERATURES WILL BE WELL ABOVE NORMAL EACH DAY. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 230 PM FRIDAY...MAJOR COLD SNAP ON TAP FOR THE EXTENDED AS AN ARCTIC AIRMASS DESCENDS UPON THE CAROLINAS. ECMWF AND GFS LONG RANGE PRODUCTS IN DECENT AGREEMENT AS TO THE GENERAL SCENARIO...WITH A DEEP H/5 TROUGH DROPPING SOUTH OVER EASTERN CONUS ON MONDAY... PUSHING AN ARCTIC FRONT WELL OFFSHORE EARLY IN THE PERIOD. A SERIES OF SHORT WAVES WILL DEEPEN AND REINFORCE THE L/W TROUGH OVER THE EASTERN SEABOARD...ESPECIALLY ON TUESDAY WHEN 1000-500MB THICKNESS VALUES WILL DROP DOWN TO AROUND 520 DECAMETERS. TIME-HEIGHT CROSS SECTIONS SHOW A GENERALLY DRY AIR MASS SO DO NOT EXPECT ANY PRECIPITATION DURING THIS PERIOD. TEMPERATURES WILL BE WELL BELOW NORMAL THROUGH THE EXTENDED...WITH LOWS IN THE 20S THROUGH THURSDAY MORNING. TUESDAY LOOKS TO BE THE COLDEST DAY WITH STRONG COLD AIR ADVECTION IN PLACE. EXPECTING HIGHS IN THE LOWER 40S ON TUESDAY...WITH LOWS TUESDAY NIGHT OF AROUND 20 MANY LOCATIONS... PERHAPS DROPPING INTO THE TEENS IN OUR NORMALLY COLDER LOCATIONS. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 06Z...HAVE SLOWED UP THE PROGRESS OF THE FRONT FROM THE 00Z PACKAGE. LATEST GUIDANCE SHOWING SOME PCPN WITH THIS FRONT MAINLY ACROSS LBT AND FLO TERMINALS. HAVE DECIDED TO MENTION VCSH IN THOSE TERMINALS AND ALSO AT ILM AS THE FRONT MOVES EAST. HAVE LEFT PCPN OUT OF CRE AND MYR AS MOISTURE IS VERY LIMITED IN THESE AREAS . CONFIDENCE LEVEL IN ANY PCPN AT THE TERMINALS IS MEDIUM. ANY PCPN THAT DOES FALL WILL BE VERY LIGHT NO MORE THAN .01 BUT MORE LIKE A TRACE WHICH WILL HAVE NO AVIATION IMPACT. AS FRONT MOVES EAST LOOK FOR GOOD MIXING BEHIND THE FRONT TO USHER IN SOME GUSTY WINDS DURING THE AFTERNOON THAT WILL ABATE AS THE SUN SETS THIS EVENING. HAVE KEPT CEILINGS/VSBY AT VFR THROUGHOUT THE PERIOD WITH VERY GOOD CONFIDENCE HERE. EXTENDED OUTLOOK...POSSIBLE IFR SUNDAY MORNING INLAND TERMINALS. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 915 PM FRIDAY...COLD SHELF WATERS LIMITING THE WAA WINDS AHEAD OF THE COLD FRONT TO SW 10-15 KT. THE WARMER SHELF WATERS...IE. 70 DEGREES AT FPSN7...JUST OUTSIDE THE COASTAL WATERS OFF CAPE FEAR WILL DEFINITELY SEE THE HIGHER WINDS MIX DOWN TO THE OCEAN SFC. LOW LEVEL JET AHEAD OF THE COLD FRONT WITH 925MB 30-40 KT SW WINDS PROGGED...WILL HAVE A BETTER CHANCE TO MIX DOWN TO THE OCEAN SFC WHERE SSTS ARE IN THE UPPER 60S AND HIGHER. THE COOLER SHELF WATERS WILL LIMIT OVERALL SW WINDS TO 10-15 KT. THE OTHER DRIVING FORCE WILL BE FROM THE TIGHTENING SFC PG AHEAD OF THE COLD FRONT. THIS COULD BOOST WINDS A BIT HIGHER. HAVE INDICATED SW 15-20 KT WINDS ACROSS THE OUTER WATERS OF THE ILM COASTAL WATERS. WILL HAVE TO MONITOR THE SFC PG AND LIKELY ISSUE WIND SPEED UPDATES IF THE SFC PG FURTHER TIGHTENS AS OPPOSED TO WINDS MIXING DOWN FROM ALOFT. DOMINATE SEAS EARLY THIS EVENING ARE FROM A 1 TO 2 FOOT DECAYING EASTERLY SWELL AT 12-14 SECOND PERIODS. SHORT PERIOD WIND DRIVEN WAVES WILL LIKELY DOMINATE SIG. SEAS BY AND AFTER MIDNIGHT. THE OUTER WATERS OFF CAPE FEAR WILL HAVE THE BEST POTENTIAL TO REACH SCEC/SCA CRITERIA DEPENDING HOW CLOSE THOSE WARMER SSTS REACH. SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 230 PM FRIDAY...WESTERLY FLOW IN THE WAKE OF A COLD FRONT SATURDAY MORNING WILL RANGE FROM 15-20 KT AWAY FROM THE COAST AND 10-15 KT NEAR SHORE. THE OFFSHORE DIRECTION WILL LIMIT WAVE GROWTH NEARSHORE AS WELL...BUT SEAS AWAY FROM THE COAST SATURDAY WILL BE 3-5 FT (HIGHEST OFF CAPE FEAR). WINDS WILL DIMINISH SATURDAY NIGHT THEN BEGIN TO BACK TO THE SOUTHWEST SUNDAY MORNING. THE PRESSURE GRADIENT WILL INCREASE DURING SUNDAY AHEAD OF THE NEXT COLD FRONT THAT IS EXPECTED TO CROSS THE WATERS SUNDAY EVENING. COULD SEE A BRIEF PERIOD OF SMALL CRAFT CONDITIONS BY SUNDAY EVENING. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 230 PM FRIDAY...A STRONG ARCTIC COLD FRONT WILL MOVE ACROSS THE WATERS EARLY ON MONDAY...BRINGING STRONG NWLY WINDS AND HAZARDOUS SEAS TO THE COASTAL WATERS THROUGH THE LONG TERM. COLD SURGE LOOKS TO BE THE COLDEST ON TUESDAY MORNING...WITH NW WINDS IN THE 20 TO 30 KT RANGE...AND SEAS BUILDING TO 6 FT OR SO OVER THE OUTER PORTIONS OF OUR WATERS. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...DCH SHORT TERM...SRP LONG TERM...REK AVIATION...MAC/RJD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1004 PM CST FRI DEC 30 2011 .DISCUSSION...BASED ON NON DIURNAL TEMPERATURE TRENDS...MADE SOME CHANGES TO PRECIP TYPE TONIGHT. ALSO...THE LATEST RUC AND NWS RADARS RADARS SUGGEST THE NORTHWEST IS OUT OF PRECIPITATION THREAT. WAMER BY 2 TO 3 DEGREES ACROSS SOUTHWEST...SO LOOKS MORE LIKE RAIN. FREEZING RAIN THREAT CONTIUES CENTRAL AND EAST ALONG WITH SNOW. && .AVIATION...HAZARDS TO AVIATION THIS PERIOD...FREEZING RAIN...IFR CONDITIONS...AND STRONG SURFACE WINDS LATE IN THE PERIOD. AT 10 PM CST...A WARM FRONT EXTENDED FROM LOW PRESSURE IN CENTRAL SASKATCHEWAN INTO WESTERN NORTH DAKOTA. FRONT WILL MOVE EAST AND BE THE FOCUS FOR A MIX OF RAIN...FREEZING RAIN AND SNOW ACROSS WEST AND CENTRAL NORTH DAKOTA TONIGHT. IFR CONDITIONS AT KJMS WILL BECOME MVFR AND EVENTUALLY VFR AFTER WARM FRONTAL PASSAGE. VFR TO OCNLY MVFR AT KBIS/KMOT/KISN/KDIK TIL 10Z...THEN VFR. THREAT OF FREEZING RAIN AT KMOT/KBIS/KJMS BETWEEN 04-10Z. GUSTY WINDS TO 45 KT AFTER 16Z SATURDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING FROM 9 AM CST /8 AM MST/ SATURDAY TO 1 PM CST /NOON MST/ SUNDAY FOR NDZ001>003-009>011-017>021-031>035-040>046. WIND ADVISORY FROM NOON SATURDAY TO 6 PM CST SUNDAY FOR NDZ004- 005-012-013-022-023-025-036-037-047-048-050-051. && $$ SHORT TERM...WAA AVIATION...WAA
AREA FORECAST DISCUSSION
NWS PUEBLO CO
333 AM MST SAT DEC 31 2011 .SHORT TERM... (TODAY AND TONIGHT) ...STRONG WINDS EXPECTED ACROSS THE CENTRAL AND EASTERN MOUNTAINS...NORTHERN I-25 CORRIDOR...AND NRN PORTIONS OF THE SOUTHEAST PLAINS TODAY... CURRENTLY...IR SATELLITE IMAGERY ALONG WITH H5 RUC ANALYSIS CLEARLY SHOWS THE APPROACHING SHORTWAVE CROSSING THE GREAT BASIN AND NORTHERN ROCKIES THIS AM...WITH THE TROF AXIS ROUGHLY OVER ID AND W MT AS OF 3 AM. SLC SFC OBS HAVE REPORTED HEFTY PRESSURE RISES...WHILE CLOSER TO HOME WINDS HAVE BEEN ON THE INCREASE ACROSS THE HIGHER ELEVATIONS. THE SENSOR ON PIKES PEAK REPORTED AN 84 MPH GUSTS AT 1 AM...SO STRONG WINDS ARE COMING AS THE PRESSURE GRADIENT TIGHTENS. TODAY...THE UPPER JET THAT IS CARVING OUT THE BASE OF THIS SHORTWAVE TROUGH HAS A CORE OF 100-110 KTS...AND IS EXPECTED TO SLIDE ACROSS THE STATE TODAY. STRONGW-SW WINDS THIS MORNING WILL QUICKLY SHIFT TO A NW DIRECTION AND STRENGTHEN THROUGH THE MORNING AS THE TROUGH MOVES EAST...WITH BOTH THE NAM AND GFS MODELS INDICATING THAT THE TROUGH AXIS WILL BE NEAR THE CO AND KS BORDER BY MIDDAY. MODEL CROSS SECTIONS SHOW A RAPID INTENSIFICATION OF WINDS AS THEY DROP TOWARDS THE SFC BETWEEN 12Z AND 18Z...AND GUSTS TO 60 MPH FOR THE LOWER ELEVATIONS ARE PROBABLE THIS MORNING. HOW WIDESPREAD THESE GUSTS WILL BE IS A QUESTION...BUT FEEL THAT MANY WILL EXPERIENCE HIGH WINDS TODAY. THEREFORE...THE HIGH WIND WARNING ALREADY IN PLACE FOR MUCH OF THE HIGHER TERRAIN...THE UPPER ARKANSAS RIVER VALLEY...MUCH OF THE I25 CORRIDOR AND FOR PORTIONS OF THE PLAINS ALONG HIGHWAY 50 AND NORTH LOOKS GOOD. THERE IS SOME CONCERN ON WHETHER OR NOT THE REST OF THE PLAINS NEED SOME SORT OF HIGHLIGHT...BUT GUT FEELING IS THAT THESE AREAS...THOUGH THEY WILL GET WINDY...WILL NOT REACH HIGH WIND CRITERIA IN A WIDE ENOUGH AREA. AS FOR TEMPS AND PCPN CHANCES...A RELATIVELY MILD NIGHT DUE TO THE INCREASING WINDS SHOULD GIVE A BOOST TO MAX TEMPS TODAY...AND TEMPS IN THE 50S WITH 40S FOR THE HIGH VALLEYS IS FORECAST. AS FOR PCPN...ONLY AREA THAT LOOKS LIKE IT WILL RECEIVE ANY SIGNIFICANT PCPN WILL BE THE CENT MTS AS THE W-NW FLOW ALOFT IS FAVORABLE FOR THAT AREA. LATEST MODELS CONTINUE TO PAINT AROUND ONE INCH OF SNOW POSSIBLE THROUGH THE DAY. FINALLY...AREAS OF BLOWING SNOW WILL BE A HAZARD OVER THE HIGHER MTN PASSES THIS MORNING AND TODAY. TONIGHT...AS THE UPPER DISTURBANCE PASSES TO THE EAST...THE SFC COLD FRONT DROPS DOWN THE E PLAINS SOME TIME AROUND 00Z. AS WINDS DIE DOWN...CLEARING SKIES AND COLD AIR FILTERING IN WILL SET THE STAGE FOR A COLD NIGHT WITH MIN TEMPS IN THE TEENS AND SINGLE DIGITS...AND BELOW ZERO FOR PORTIONS OF THE SLV. MOORE .LONG TERM... ...JANUARY THAW... NOT MUCH SIGNIFICANT WEATHER IS ANTICIPATED DURING THIS PERIOD. A LARGE RIDGE OF HIGH PRESSURE ALOFT WILL BUILD OVER THE REGION STARTING MONDAY AND LAST THROUGH LATE WEEK. A WEAK DISTURBANCE WILL MOVE THROUGH THE RIDGE DURING THE TUESDAY TIME FRAME BUT THIS FEATURE IS RATHER WEAK AND NO SENSIBLE WX IS EXPECTED WITH IT. MAX TEMPERATURES FCSTED ATTM THROUGH MOST OF THE WEEK OVER THE PLAINS WILL BE 50S TO AROUND 60F...BUT THESE NUMBERS WILL LIKELY NEED TO BE ADJUSTED UPWARDS...ESPECIALLY ON THURSDAY AS 700 MB TEMPS ARE FCST TO BE IN THE +8 RANGE (WHICH WOULD EQUAL TEMPS AROUND 70F IF WE MIX DOWN DRY ADIABATICALLY). BY LATE IN THE WEEK A MORE AMPLIFIED PAC TROUGH IS FCST TO MOVE INTO THE REGION. ATTM THE BEST CHANCE OF PRECIP OVER THE AREA WOULD BE LATE FRIDAY INTO EARLY SATURDAY. TEMPS SHOULD COOL DOWN FOR NEXT WEEKEND. /HODANISH && .AVIATION... VFR CONDITIONS FOR THE NEXT 24 HRS EXPECTED FOR KALS. FOR KCOS AND KPUB...THE MAIN CONCERN WILL BE STRONG W-NW WINDS DEVELOPING THIS MORNING AND LASTING THROUGH 22Z. WILL MAINTAIN MENTION OF WIND SHEAR FOR KCOS EARLY THIS MORNING THROUGH 14Z OR SO...BEFORE THE STRONGER WINDS ALOFT MAKE IT DOWN TO THE SFC. WIND SHEAR DOES NOT LOOK TO BE AN ISSUE FOR KPUB. GUSTS OF 45-50 KTS WILL BE POSSIBLE AT BOTH SITES...AND ALONG THE I25 CORRIDOR...THROUGH THE MORNING AND EARLY AFTERNOON. && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ061-062- 077-078-083>087-089-095-096. HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ058-060- 063-072-073-075-076-079>082. && $$ 27/34
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
744 AM CST SAT DEC 31 2011 .UPDATE... MINOR UPDATE TO BETTER REFLECT CURRENT CLOUD TRENDS. LOCALLY DENSE FOG IS SLOWLY IMPROVING AS THE INVERTED TROF CONTINUES MOVING EAST. ..08.. && .PREV DISCUSSION... /ISSUED 548 AM CST SAT DEC 31 2011/ AVIATION... VLIFR TO MVFR CONDITIONS WILL IMPROVE TO VFR THROUGH 18Z/31. LLWS APPEARS TO BE MARGINAL AHEAD OF A STORM SYSTEM 21Z/31 TO 02Z/01 BUT LOW LEVEL TURBULENCE IS LIKELY. AFT 03Z/01 CONDITIONS WILL DETERIORATE WITH RA DVLPG. CIGS WERE KEPT VFR BUT MVFR CONDITIONS ARE POSSIBLE AFT 03Z/01. STRONG COLD FRONT CHANGES RA TO SN AFT 06Z/01 WITH WINDS INCREASING SIGNIFICANTLY. THERE ARE QUESTIONS AS TO WHETHER THE 40-50 KT WINDS ARND 2KFT AGL WILL MIX DOWN TO THE SURFACE. IF NO MIXING DOWN OCCURS THEN THERE IS A POTENTIAL FOR LLWS AFT 06Z/01. .08.. PREV DISCUSSION... /ISSUED 335 AM CST SAT DEC 31 2011/ SYNOPSIS... 06Z SFC ANALYSIS HAS A LOW IN NORTHWEST SOUTH DAKOTA WITH A WARM FRONT RUNNING SOUTHEAST TO NEAR KSUX. A TROF RAN FROM A LOW IN SOUTHERN LAKE HURON INTO CENTRAL ILLINOIS AND THEN NORTHWEST INTO SOUTHEAST MINNESOTA. DEW POINTS WERE GENERALLY IN THE 20S AND 30S ACROSS THE MIDWEST. SATELLITE HAS AN AREA OF LOW CLOUDS ACROSS EASTERN IOWA AND MOST OF ILLINOIS TRAPPED UNDER AN INVERSION WITH MID AND HIGH CLOUDS MOVING EAST FROM THE ROCKIES. SHORT TERM...TODAY AND TONIGHT THERE ARE MANY CONCERNS OVER THE NEXT 36 HRS. IN THE IMMEDIATE SHORT TERM ARE THE CLOUDS AND FOG POTENTIAL. THE LOW CLOUDS ACROSS THE AREA ARE TRAPPED UNDER AN INVERSION. RUC TRENDS MAINTAIN THE INVERSION FOR MOST OF THE MORNING BEFORE BREAKING IT UP AROUND MID DAY. IF CORRECT...THEN THE CLOUD COVER WILL HOLD DOWN TEMPERATURES TODAY. AS FOR THE FOG...IT IS ONLY PATCHY IN SPOTS RIGHT NOW AND IT WILL BE MONITORED. AN SPS MAY BE ISSUED FOR THOSE AREAS WHERE THE FOG IS LOCALLY DENSE. THE CLOUDS SHOULD BREAK UP DURING THE DAY RESULTING IN A QUIET AND MILD DAY FOR THE LAST DAY OF DECEMBER. ATTENTION THEN TURNS TO THE APPROACHING SYSTEM FOR TONIGHT. FIRST...ALL MODELS INITIALIZED TOO MOIST IN THE LOWER LEVELS WHEN COMPARED AGAINST THE 00Z UA DATA. THIS MOIST BIAS IS LIKELY RESULTING IN THE MODELS PUTTING OUT TOO MUCH QPF FOR TONIGHT. BASED ON THE OVERALL FORCING AND CONDENSATION PRESSURE DEFICITS THE EARLY EVENING HOURS WILL BE DRY WITH THE PRECIPITATION REMAINING IN CENTRAL IOWA. BETWEEN 9 PM AND MIDNIGHT...RAIN WILL DEVELOP OR MOVE INTO THE WESTERN CWFA AS CONTINUED WAA OCCURS AND TEMPERATURES ALOFT REMAIN ABOVE 0 CELSIUS. AFTER MIDNIGHT...STRONG CAA OCCURS AS THE FRONT MOVES THROUGH. FCST SOUNDINGS QUICKLY DROP BELOW FREEZING AND WBZ TEMPERATURES DROP BELOW FREEZING AS WELL. THUS MIDNIGHT TO 3 AM WILL SEE A FAIRLY RAPID TRANSITION FROM RAIN TO SNOW WITH A MIX FOR A FEW HOURS. AFTER 3 AM...CAA CONTINUES AND SNOW SHOULD BE SEEN ACROSS THE ENTIRE AREA. THIS EVENT WILL ONLY LAST ABOUT 6-7 HRS IN ANY ONE LOCATION ONCE IT BEGINS. SINCE ABOUT HALF OF THE EVENT WILL BE RAIN...THE SNOW AMOUNTS WILL BE QUITE LIGHT AND SHOULD BE AT WORST ONE HALF INCH. MOST AREAS WILL ONLY SEE A DUSTING OF ACCUMULATION. THE OTHER CONCERN IS THE WIND. THE STRONG CAA COMBINED WITH A STRONG PRESSURE GRADIENT WILL RESULT IN VERY STRONG WINDS. WINDS ARE PROGGED TO BE NEAR 50 KNOTS STARTING JUST ABOVE 925 MB. HOWEVER...LOW LEVEL LAPSE RATES ARE NOT OVERLY STEEP SO THE HIGHER MOMENTUM AIR ALOFT MAY HAVE TROUBLE MIXING DOWN TO THE SFC. SINCE A WIND ADVISORY IS ALREADY OUT...IT WILL BE CONTINUED. HOWEVER...THE START TIME WILL BE PUSHED BACK TO MIDNIGHT AND THE AREAL COVERAGE WILL BE EXPANDED AS WELL. 08.. LONG TERM...SUNDAY THROUGH FRIDAY... SUNDAY WILL BE VERY WINDY...SUNDAY NIGHT THROUGH MONDAY EVENING WILL BE RATHER WINDY TOO. MOST OTHER QUESTIONS ARE CONCERNED WITH CLOUD COVER AND THE AFFECT ON TEMPERATURES THROUGH THE EARLY WEEK. OTHERWISE THE EXTENDED FORECAST GENERALLY REMAINS UNCHANGED AS WE SEE ANOTHER SEVERAL DAYS OF VERY MILD WEATHER IN THE WEDNESDAY THROUGH FRIDAY PERIOD. SUNDAY...WE WILL BEGIN THE DAY WITH STRONG CAA AND STRATUS LIKELY SPREADING OVER THE AREA. ANY MOISTURE SEEMS VERY THIN...THUS FLURRIES ARE NOT INCLUDED YET. EARLY DAY WILL BE WINDY...WITH SOME WIND GUSTS BEFORE 9 AM REACHING UP AROUND 40 MPH IN THE NORTHWEST...AND 35 MPH ELSEWHERE. BETWEEN 9 AM AND SUNSET...WE SHOULD SEE WIND ADVISORY LEVELS IN MOST OF THE CWA. AT THIS POINT...OUR COUNTIES ALONG AND WEST OF THE MISSISSIPPI RIVER LOOK VERY LIKELY TO SEE WIND GUSTS OVER 45 MPH AT TIMES MID DAY SUNDAY. SOME GUSTS TO AROUND 50 MPH ARE POSSIBLE SUNDAY NOON THROUGH 2 PM SUNDAY. WITH THE CERTAINTY OF WIND CRITERIA OVER THE WESTERN HALF OF THE CWA...WILL EXTEND THE ADVISORY FURTHER EAST. THOUGH THE COUNTIES JUST EAST WILL POSSIBLY HIT CRITERIA AS WELL...THEY APPEAR MORE MARGINAL AT THIS TIME...AND WITH ONSET CLOSER TO 12Z SUNDAY IN THOSE LOCATIONS...WILL KEEP THEM OUT OF THE ADVISORY. SUNDAY NIGHT...WINDS MAY REMAIN NEAR ADVISORY LEVELS THROUGH THE EVENING...AND CURRENT HEADLINES KEEP OUR NORTHWEST COUNTIES IN ONE THROUGH 06Z MONDAY. TEMPERATURES WILL DROP INTO THE TEENS SUNDAY EVENING...AND MAY FALL TO THE RANGE OF 10 TO 15 BY MONDAY MORNING. WIND CHILLS IN THE TEENS SUNDAY WILL DROP TO THE -8 TO +5 RANGE BY MONDAY MORNING. 2012 WILL CERTAINLY ENTER WITH A GOOD DOSE OF WINTER TEMPERATURES...THIS COLD SNAP WILL BE OVER QUITE QUICKLY. AFTER A COLD NIGHT MONDAY NIGHT...TUESDAY WILL BEGIN OUR NEXT WARM UP...AS ZONAL FLOW DEVELOPS ALOFT. BY THURSDAY AND FRIDAY...TEMPERATURES COULD EASILY REACH THE 50S IN MANY PARTS OF THE CWA. ERVIN.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR BENTON-CEDAR-CLINTON-DES MOINES-HENRY IA-IOWA-JACKSON- JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-MUSCATINE- SCOTT-VAN BUREN-WASHINGTON. WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR BUCHANAN-DELAWARE-DUBUQUE. IL...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR JO DAVIESS-MERCER-ROCK ISLAND. MO...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR CLARK- SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
548 AM CST SAT DEC 31 2011 .AVIATION... VLIFR TO MVFR CONDITIONS WILL IMPROVE TO VFR THROUGH 18Z/31. LLWS APPEARS TO BE MARGINAL AHEAD OF A STORM SYSTEM 21Z/31 TO 02Z/01 BUT LOW LEVEL TURBULENCE IS LIKELY. AFT 03Z/01 CONDITIONS WILL DETERIORATE WITH RA DVLPG. CIGS WERE KEPT VFR BUT MVFR CONDITIONS ARE POSSIBLE AFT 03Z/01. STRONG COLD FRONT CHANGES RA TO SN AFT 06Z/01 WITH WINDS INCREASING SIGNIFICANTLY. THERE ARE QUESTIONS AS TO WHETHER THE 40-50 KT WINDS ARND 2KFT AGL WILL MIX DOWN TO THE SURFACE. IF NO MIXING DOWN OCCURS THEN THERE IS A POTENTIAL FOR LLWS AFT 06Z/01. ..08.. && .PREV DISCUSSION... /ISSUED 335 AM CST SAT DEC 31 2011/ SYNOPSIS... 06Z SFC ANALYSIS HAS A LOW IN NORTHWEST SOUTH DAKOTA WITH A WARM FRONT RUNNING SOUTHEAST TO NEAR KSUX. A TROF RAN FROM A LOW IN SOUTHERN LAKE HURON INTO CENTRAL ILLINOIS AND THEN NORTHWEST INTO SOUTHEAST MINNESOTA. DEW POINTS WERE GENERALLY IN THE 20S AND 30S ACROSS THE MIDWEST. SATELLITE HAS AN AREA OF LOW CLOUDS ACROSS EASTERN IOWA AND MOST OF ILLINOIS TRAPPED UNDER AN INVERSION WITH MID AND HIGH CLOUDS MOVING EAST FROM THE ROCKIES. SHORT TERM...TODAY AND TONIGHT THERE ARE MANY CONCERNS OVER THE NEXT 36 HRS. IN THE IMMEDIATE SHORT TERM ARE THE CLOUDS AND FOG POTENTIAL. THE LOW CLOUDS ACROSS THE AREA ARE TRAPPED UNDER AN INVERSION. RUC TRENDS MAINTAIN THE INVERSION FOR MOST OF THE MORNING BEFORE BREAKING IT UP AROUND MID DAY. IF CORRECT...THEN THE CLOUD COVER WILL HOLD DOWN TEMPERATURES TODAY. AS FOR THE FOG...IT IS ONLY PATCHY IN SPOTS RIGHT NOW AND IT WILL BE MONITORED. AN SPS MAY BE ISSUED FOR THOSE AREAS WHERE THE FOG IS LOCALLY DENSE. THE CLOUDS SHOULD BREAK UP DURING THE DAY RESULTING IN A QUIET AND MILD DAY FOR THE LAST DAY OF DECEMBER. ATTENTION THEN TURNS TO THE APPROACHING SYSTEM FOR TONIGHT. FIRST...ALL MODELS INITIALIZED TOO MOIST IN THE LOWER LEVELS WHEN COMPARED AGAINST THE 00Z UA DATA. THIS MOIST BIAS IS LIKELY RESULTING IN THE MODELS PUTTING OUT TOO MUCH QPF FOR TONIGHT. BASED ON THE OVERALL FORCING AND CONDENSATION PRESSURE DEFICITS THE EARLY EVENING HOURS WILL BE DRY WITH THE PRECIPITATION REMAINING IN CENTRAL IOWA. BETWEEN 9 PM AND MIDNIGHT...RAIN WILL DEVELOP OR MOVE INTO THE WESTERN CWFA AS CONTINUED WAA OCCURS AND TEMPERATURES ALOFT REMAIN ABOVE 0 CELSIUS. AFTER MIDNIGHT...STRONG CAA OCCURS AS THE FRONT MOVES THROUGH. FCST SOUNDINGS QUICKLY DROP BELOW FREEZING AND WBZ TEMPERATURES DROP BELOW FREEZING AS WELL. THUS MIDNIGHT TO 3 AM WILL SEE A FAIRLY RAPID TRANSITION FROM RAIN TO SNOW WITH A MIX FOR A FEW HOURS. AFTER 3 AM...CAA CONTINUES AND SNOW SHOULD BE SEEN ACROSS THE ENTIRE AREA. THIS EVENT WILL ONLY LAST ABOUT 6-7 HRS IN ANY ONE LOCATION ONCE IT BEGINS. SINCE ABOUT HALF OF THE EVENT WILL BE RAIN...THE SNOW AMOUNTS WILL BE QUITE LIGHT AND SHOULD BE AT WORST ONE HALF INCH. MOST AREAS WILL ONLY SEE A DUSTING OF ACCUMULATION. THE OTHER CONCERN IS THE WIND. THE STRONG CAA COMBINED WITH A STRONG PRESSURE GRADIENT WILL RESULT IN VERY STRONG WINDS. WINDS ARE PROGGED TO BE NEAR 50 KNOTS STARTING JUST ABOVE 925 MB. HOWEVER...LOW LEVEL LAPSE RATES ARE NOT OVERLY STEEP SO THE HIGHER MOMENTUM AIR ALOFT MAY HAVE TROUBLE MIXING DOWN TO THE SFC. SINCE A WIND ADVISORY IS ALREADY OUT...IT WILL BE CONTINUED. HOWEVER...THE START TIME WILL BE PUSHED BACK TO MIDNIGHT AND THE AREAL COVERAGE WILL BE EXPANDED AS WELL. .08.. LONG TERM...SUNDAY THROUGH FRIDAY... SUNDAY WILL BE VERY WINDY...SUNDAY NIGHT THROUGH MONDAY EVENING WILL BE RATHER WINDY TOO. MOST OTHER QUESTIONS ARE CONCERNED WITH CLOUD COVER AND THE AFFECT ON TEMPERATURES THROUGH THE EARLY WEEK. OTHERWISE THE EXTENDED FORECAST GENERALLY REMAINS UNCHANGED AS WE SEE ANOTHER SEVERAL DAYS OF VERY MILD WEATHER IN THE WEDNESDAY THROUGH FRIDAY PERIOD. SUNDAY...WE WILL BEGIN THE DAY WITH STRONG CAA AND STRATUS LIKELY SPREADING OVER THE AREA. ANY MOISTURE SEEMS VERY THIN...THUS FLURRIES ARE NOT INCLUDED YET. EARLY DAY WILL BE WINDY...WITH SOME WIND GUSTS BEFORE 9 AM REACHING UP AROUND 40 MPH IN THE NORTHWEST...AND 35 MPH ELSEWHERE. BETWEEN 9 AM AND SUNSET...WE SHOULD SEE WIND ADVISORY LEVELS IN MOST OF THE CWA. AT THIS POINT...OUR COUNTIES ALONG AND WEST OF THE MISSISSIPPI RIVER LOOK VERY LIKELY TO SEE WIND GUSTS OVER 45 MPH AT TIMES MID DAY SUNDAY. SOME GUSTS TO AROUND 50 MPH ARE POSSIBLE SUNDAY NOON THROUGH 2 PM SUNDAY. WITH THE CERTAINTY OF WIND CRITERIA OVER THE WESTERN HALF OF THE CWA...WILL EXTEND THE ADVISORY FURTHER EAST. THOUGH THE COUNTIES JUST EAST WILL POSSIBLY HIT CRITERIA AS WELL...THEY APPEAR MORE MARGINAL AT THIS TIME...AND WITH ONSET CLOSER TO 12Z SUNDAY IN THOSE LOCATIONS...WILL KEEP THEM OUT OF THE ADVISORY. SUNDAY NIGHT...WINDS MAY REMAIN NEAR ADVISORY LEVELS THROUGH THE EVENING...AND CURRENT HEADLINES KEEP OUR NORTHWEST COUNTIES IN ONE THROUGH 06Z MONDAY. TEMPERATURES WILL DROP INTO THE TEENS SUNDAY EVENING...AND MAY FALL TO THE RANGE OF 10 TO 15 BY MONDAY MORNING. WIND CHILLS IN THE TEENS SUNDAY WILL DROP TO THE -8 TO +5 RANGE BY MONDAY MORNING. 2012 WILL CERTAINLY ENTER WITH A GOOD DOSE OF WINTER TEMPERATURES...THIS COLD SNAP WILL BE OVER QUITE QUICKLY. AFTER A COLD NIGHT MONDAY NIGHT...TUESDAY WILL BEGIN OUR NEXT WARM UP...AS ZONAL FLOW DEVELOPS ALOFT. BY THURSDAY AND FRIDAY...TEMPERATURES COULD EASILY REACH THE 50S IN MANY PARTS OF THE CWA. .ERVIN.. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR BENTON-CEDAR-CLINTON-DES MOINES-HENRY IA-IOWA-JACKSON- JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-MUSCATINE- SCOTT-VAN BUREN-WASHINGTON. WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR BUCHANAN-DELAWARE-DUBUQUE. IL...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR JO DAVIESS-MERCER-ROCK ISLAND. MO...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST SUNDAY FOR CLARK- SCOTLAND. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
750 AM EST SAT DEC 31 2011 UPDATED AVIATION DISCUSSION FOR 12Z TAFS .SYNOPSIS... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW PATTERN OVER NAMERICA. THERE IS A NEAR ZONAL NRN BRANCH FLOW ACRS SRN CAN WITH A DISTURBANCE OF NOTE MOVING E THRU SASKATCHEWAN. OF NOTE THERE IS ALMOST A COMPLETE ABSENCE OF ARCTIC AIR IN THIS AREA...WITH THE LOWEST 00Z H85 TEMP ONLY -9C IN NRN BRITISH COLUMBIA. A MORE ACTIVE SRN BRANCH FLOW IS PRESENT IN THE CONUS. A FAIRLY DEEP TROF IS NOTED OVER THE GREAT LKS INTO THE OH RIVER VALLEY...SUPPORTING A SFC LO IN OH THAT IS MOVING E. UNDER AN UPR RDG IN THE CNTRL PLAINS...12Z-24Z H3 RISES OVER 200M ARE PRESENT... BUT THERE IS ONLY A WEAK SFC HI PRES RDG STRETCHING FM MN INTO WI ON THE NW FLANK OF THE SFC LO TO THE SE. LOCAL 00Z RAOBS SHOW SHARP SUBSIDENCE INVRN BTWN H875 AT GRB/APX AND H925 AT INL. THE SUB INVRN LYR IS RELATIVELY MOIST...SO LO CLDS ARE PRESENT OVER MUCH OF THE AREA. HOWEVER...THE LO CLDS HAVE DISSIPATED IN A SWATCH FM NE MN INTO NCNTRL WI AND OVER PARTS OF SCNTRL UPR MI. TEMPS IN THESE AREAS HAVE FALLEN AS LO AS 5 TO 10F. LOOKING FARTHER W...A VIGOROUS SHRTWV IS PLOWING THRU THE PAC NW...ACCOMPANIED BY 12Z-24Z H3 FALLS OVER 200M. RIGHT IN THE PATH OF THIS DISTURBANCE...A LINE OF SVR TS ACCOMPANIED BY SN STRUCK NEAR BOISE ID. && .DISCUSSION... MAIN FCST CONCERNS THIS PACKAGE FOCUS ON DETAILS OF UPCOMING SN STORM THAT IS FCST WITH DEVELOPMENT OF DEEP LO PRES SOMEWHERE NEAR UPR MI BY SUN. TDAY...A RELATIVELY QUIET PERIOD IS ON TAP FOR TODAY AS UPR RDG IN THE PLAINS DRIFTS E ACRS THE UPR LKS. WITH STRONGER SUBSIDENCE AHEAD OF THIS RDG...SUSPECT THE LO CLDS MAY BREAK UP A BIT EARLY THIS MRNG...UNLESS THE INVRN JUST SHARPENS AND CONTINUES TO TRAP THE LLVL MSTR. THE LO CLDS ARE LIKELY TO BE THE MOST RESILIENT OVER THE E NEAR LINGERING WEAK LO PRES TROF. THEN...NRN BRANCH SHRTWV IS FCST TO MOVE TO NEAR LK WINNIPEG WHILE THE STRONGER SRN BRANCH DISTURBANCE DIGS TO NEAR OMAHA BY 00Z SUN. THE STRENGTHENING SW FLOW AHEAD OF THESE FEATURES WL BRING MAINLY MID/HI CLDS INTO THE AREA WITH VERY DRY AT H85 LINGERING THRU THE DAY. MOST MODELS NOW GENERATE LTL OF NO PCPN OVER THE CWA THRU 00Z...SO RESTRICTED POPS TO THE FAR W CLOSER TO THE DEEPER MSTR FCST OVER MN/WRN LK SUP. EXPECT THE HIEST TEMPS INTO THE 30S OVER THE W NEAR LK SUP WHERE S WIND DOWNSLOPES. SINCE NAM WBLB ZERO HGT IS FCST TO BE AOA 1K FT IN THIS AREA OVER THE W...INCLUDED A MENTION OF RA/SN MIX WITH THE LGT PCPN EVEN THOUGH THE DRY AIR AT H85 WL TEND TO BRING ABOUT SOME EVAP COOLING. TNGT...THERE CONTINUES TO BE A LARGE SPREAD ON HOW QUICKLY THE SFC LO DEEPENS IN ASSOCIATION WITH MAINLY THE VIGOROUS SRN BRANCH DISTURBANCE NOW MOVING TOWARD THE NRN ROCKIES. CONSIDERING THE LACK OF ARCTIC AIR IN CAN AND THE SEPARATE BRANCHES OF FLOW OVER NAMERICA...NCEP FAVORS TRENDING AWAY FM THE CONSISTENTLY DEEPER GFS SCENARIO...WITH A BLEND OF THE 00Z NAM AND THE CONSISTENTLY WEAKER 12Z ECMWF. WHILE THE NRN BRANCH FEATURES DRIFT E THRU ONTARIO...THE 2 FAVORED MODELS SHOW THE SFC LO ASSOCIATED WITH THE SRN BRANCH SHRTWV REACHING NRN LK MI BY 12Z SUN...WITH NAM/ECMWF INTENSITY DOWN TO 993MB/999MB. EXPECT PCPN TO OVERSPREAD THE CWA W-E UNDER DPVA/UPR DVGC RELATED TO 12HR H5 FALLS UP TO 200M AND THE ARRIVAL OF MORE LLVL MSTR. SHARER H85-7 FGEN RELATED TO THE PASSAGE OF THE COLD FNT ASSOCIATED WITH THE NRN BRANCH DISTURBANCE/DEEPENING SRN BRANCH LO IS FCST TO ARRIVE AFT 06Z...SO EXPECT HIER POPS THEN. GRADUAL ARRIVAL OF COLDER AIR...H85 TEMPS ARE PROGGED TO FALL TO -8 TO -9C NEAR IWD BY 12Z SUN AS NRN BRANCH DISTURBANCE TAPS COLDER H85 AIR IN WRN CAN...WITH NW H85 FLOW IN THE PRESENCE OF DEEPER MSTR WL BRING SOME LK ENHANCED SN THERE. ALTHOUGH THE PCPN MAY BE MIXED WITH RA AT THE ONSET...THE COMBINATION OF DYNAMIC/EVAP COOLING WL CHANGE THE PCPN TO MAINLY SN FAIRLY QUICKLY EXCEPT NEAR THE LK MI SHORE. SUN/SUN NGT...AS THE NRN BRANCH DISTURBANCE GRADUALLY PHASES WITH THE SRN BRANCH SHRTWV...THE SFC LO IS FCST TO DEEPEN TO THE E OF UPR MI...MORE SLOWLY BY THE ECMWF TO 992MB...VS 989MB FOR THE NAM BY 00Z MON. BOTH MODELS SHOW THE LO DEEPENING TO ARND 987MB OVER WRN QUEBEC BY 12Z MON. COLDER AIR IS GRADUALLY ADVECTED INTO THE UPR GRT LKS... WITH H85 TEMPS PROGGED TO FALL TO -13C/-15C BY 00Z MON OVER WRN LK SUP AS H85 NW WINDS INCRS TO 40-50KTS IN THE WAKE OF THE LO TO THE E. THIS FLOW TENDS TO VEER MORE NNW ON SUN NGT FOLLOWING WHAT APPEARS TO THE PASSAGE OF THE ORIGINAL NRN BRANCH SHRTWV. THE ECMWF FCSTS H85 TEMPS SINKING AS LO AS -19C AT 12Z MON FOLLOWING THIS PASSAGE. ALTHOUGH BOTH THE NAM AND ECWMF...ESPECIALLY THE ECMWF... SHOW SOME DRIER AIR IN THE MID LVLS IMPACTING THE FAR W FOR A TIME ON SUN AS THE DEEPER QVECTOR CNVGC AND UPR DVGC LIFT AWAY TO THE ENE...THE COMBINATION OF LLVL CYC FLOW/DEEP MSTR IMPACT THE CWA THRU THIS TIME. THE ARRIVAL OF THE COLDER AIR WL ALSO TEND TO INCRS WIND SPEEDS...RESULTING IN CONSIDERABLE BLSN AS WELL AS THE LK ENHANCED SN WITH CONSIDERABLE OMEGA WITHIN THE DGZ. EXPECT NO MORE THAN SCT -SHSN OVER THE SCNTRL WITH DOWNSLOPE WIND...BUT SOME BLOWING SN IS LIKELY EVEN THERE...ESPECIALLY IN AREAS THAT PICK UP A FEW INCHES TNGT. MON/MON NGT...A NNW FLOW OF COLD AIR WL PERSIST THRU THIS TIME WITHIN H85 THERMAL TROF AND TEMPS FALLING NEAR -20C PER THE 12Z ECMWF. HOWEVER...AS THE CLOSED LO TO THE E EXITS FARTHER AWAY... MODELS IN GOOD AGREEMENT SHOWING DEEPER MSTR EXITING/INVRN BASE SUBSIDING W-E ON MON WITH THE ONSET OF DNVA/LARGE SCALE QVECTOR DVGC/SUBSIDENCE UNDER H5 RISES UP TO 180M AT IWD BTWN 18Z MON AND 06Z TUE. SO SHSN INTENSITY SHOULD DIMINISH W-E...BUT BE MORE RESILIENT OVER THE E WITH LONGER DURATION OF NLY FLOW/LOWER HGTS/ LOWER H85 TEMPS. WITH WEAKENING PRES GRADIENT...EXPECT THE BLSN TO SLOWLY SUBSIDE W-E AS WELL. SINCE SKIES WL LIKELY CLEAR MON NGT OVER AT LEAST THE W HALF...TENDED TO GO QUITE A BIT LOWER FOR MIN TEMPS WITH SFC RDG AXIS/LGT WINDS ARRIVING AND PWAT UNDER 50 PCT OF NORMAL. AS FAR AS HEADLINES ARE CONCERNED...OPTED TO UPGRADE WATCHES TO WRNGS OVER THE W HALF WHERE SGFNT SN WL BE FALLING IN THE 2ND PERIOD AND POSSIBLY IMPACT NEW YEARS EVE CELEBRATIONS. OPTED TO KEEP WATCH GOING FOR AREAS E OF MQT AS THE SGNFT WX WL NOT DEVELOP UNTIL THE 3RD PERIOD. THE BLIZZARD WATCH FOR THE NW ZNS THAT BEGAN AT 06Z PRESENTED A QUANDARY BECAUSE THE WX TNGT WL NOT MEET BLIZZARD CRITERIA FM WHEN THE ACCUMULATING SN WL ARRIVE ARND 03Z THRU AT LEAST 12Z SUN. SO OPTED TO GO WITH A WINTER STORM WRNG THERE. SINCE BLIZZARD CONDITIONS ARE LIKELY ON SUN/MON...LATER SHIFTS WL LIKELY NEED TO UPGRADE THE WRNG TO A BLIZZARD. DID HIGHLIGHT THE ONSET OF BLIZZARD CONDITONS ON SUN IN THE STATEMENT. THE WATCH FOR E OF MQT MAY ALSO NEED TO BE UPGRADED TO A BLIZZARD WRNG AT SOME TIME WITH SHSN/WIND GUSTS UP TO 60 MPH/EXTENSIVE BLOWING SN LIKELY THERE SUN AFTN INTO MON NGT. FOR THE EXTENDED FORECAST... FEW CHANGES WERE DEEMED NECESSARY...AS THE FORECAST REMAINED A BLEND OF AVAILABLE MODEL DATA. STARTING AT 12Z TUESDAY THE 500MB MAP SHOWS THE DEEP TROUGH SET UP OVER THE LOWER GREAT LAKES AND NEW ENGLAND STATES...WITH A SIGNIFICANT RIDGE BUILDING OVERHEAD. THE 500MB RIDGE WILL BECOME SUPPRESSED TUESDAY NIGHT...IN RESPONSE TO A OPEN WAVE SNEAKING IN FROM THE WEST. THE 00Z RUNS OF THE CANADIAN/ECMWF AND GFS ALL HAVE THIS FEATURE...WITH MINOR DIFFERENCES. THE 31/00Z RUN OF THE ECMWF TRIES TO CLOSE THIS FEATURE OFF ACROSS LAKE SUPERIOR AT 06Z WEDNESDAY...BEFORE IT SINKS TO THE LOWER GREAT LAKES. THE CANADIAN IS SIMILAR...BUT APPROX 250MI NW OF THE ECMWF WITH THIS FEATURE. THE RESULT IS A MORE PROGRESSIVE GFS. THIS SHOWS UP AT THE SFC TOO...WITH THE COLD FRONT/TROUGH OFF THE GFS SPLITTING THE CWA IN HALF AT 06Z WEDNESDAY. THE ECMWF IS CLOSER TO 12Z WEDNESDAY. STILL...MOST MODELS DO INDICATE RIDGING ALOFT AGAIN FOR WEDNESDAY THROUGH THE DAY FRIDAY. THE EXCEPTION TO THIS IS THE SLOWER CANADIAN RUN...WHICH STRENGTHENS THE 500MB LOW ACROSS QUEBEC AND LEADS TO A SLOW DOWN WHEN COMPARED TO THE OTHER MODELS OF AROUND 6HRS. THE NEXT FEATURE OF INTEREST AT THE SFC LOOKS TO BE OVER S CENTRAL CANADA FRIDAY MORNING...AND MAY CROSS OVER OR JUST NORTH OF LAKE SUPERIOR FRIDAY AFTERNOON/EVENING. WILL NOT CONCENTRATE OF THIS NEXT SYSTEM...DUE TO THE MODERATE CONFIDENCE. && .AVIATION /FOR THE 06Z TAF ISSUANCE/... EXPECT INCREASING SOUTHERLY WINDS TODAY...OUT AHEAD OF AN APPROACHING LOW ACROSS THE NORTHERN PLAINS. ALTHOUGH THE SPECIFIC TIMING AND TRACK OF THIS LOW REMAINS A BIT UNCERTAIN...IT SHOULD SLIDE ACROSS CENTRAL/NORTHERN LAKE MICHIGAN DURING THE DAYLIGHT HOURS SUNDAY MORNING. AT THIS TIME IT STILL LOOKS REASONABLE FOR IWD AND CMX TO FALL TO IFR AROUND 02/03Z AS THE TROUGH CROSSES AND COLDER AIR AOB -3C RUSHES IN /WITH LOW PRESSURE EXTENDING FROM ONTARIO THROUGH SW WISCONSIN AROUND 03Z/. THIS SHOULD TIME OUT FOR 07Z FOR SIMILAR CONDITIONS AT SAW...BEFORE WINDS BEGIN TO PICK UP TOWARD SUNRISE SUNDAY AT IWD AND SAW...WITH BLSN LIKELY NEEDING TO BE ADDED TO THE TAFS WITH THE NEXT UPDATE/AMENDMENT. AS NOTED IN THE PREVIOUS DISCUSSION WITH CONTINUED STRONG N-NW FLOW AT CMX...ADVERSE CONDITIONS AT OR BLO AIRPORT MINS SHOULD CONTINUE INTO MONDAY. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... LOWER GREAT LAKES LOW PRESSURE WILL EXIT TO THE NEW ENGLAND SEABOARD TODAY. IN ITS WAKE...LOW PRESSURE STRETCHING FROM WESTERN MANITOBA THROUGH THE DAKOTAS CAN BE EXPECTED TO DEEPEN NEAR NORTHERN LM SUNDAY MORNING...BEFORE SHIFTING ACROSS QUEBEC MONDAY...WHILE KEEPING A SIGNIFICANT TROUGH ACROSS LS AND UPPER MI. AHEAD OF STRONG HIGH PRESSURE OVER THE PLAINS STATES MONDAY MORNING WORKING A RIDGE WEST TO EAST ACROSS LS TUESDAY...STRONG N TO NW STORM FORCE WINDS LIKELY CENTRAL AND EAST SUNDAY AFTERNOON THROUGH MONDAY. THE RUSH OF COLD AIR AND HIGH WAVES WILL RESULT IN PERIODS OF MODERATE TO HEAVY FREEZING SPRAY AS WELL. A LOW PRESSURE SYSTEM OVER CENTRAL CANADA TUESDAY AFTERNOON WILL SHIFT SOUTHEASTWARD INTO HUDSON BAY...DRAGGING A TROUGH OVER THE UPPER GREAT LAKES ON WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER STORM WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 7 PM EST /6 PM CST/ MONDAY FOR MIZ001>003-009-084. WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT FOR MIZ006-007-085. WINTER STORM WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY FOR MIZ004-005. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST MONDAY FOR MIZ010. LAKE SUPERIOR... STORM WARNING FROM 7 AM SUNDAY TO 10 PM EST MONDAY FOR LSZ264>267. HEAVY FREEZING SPRAY WATCH FROM SUNDAY EVENING THROUGH TUESDAY MORNING FOR LSZ162-263>267. STORM WARNING FROM 11 AM SUNDAY TO 10 PM EST MONDAY FOR LSZ248>251. STORM WARNING FROM 11 AM SUNDAY TO 4 PM EST MONDAY FOR LSZ243>247. STORM WARNING FROM 11 AM EST /10 AM CST/ SUNDAY TO 7 AM EST /6 AM CST/ MONDAY FOR LSZ241-242. GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 11 AM EST /10 AM CST/ MONDAY FOR LSZ240. GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 1 PM EST /NOON CST/ MONDAY FOR LSZ162. STORM WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ263. LAKE MICHIGAN... GALE WARNING FROM 5 AM SUNDAY TO 1 AM EST TUESDAY FOR LMZ221-248- 250. && $$ SYNOPSIS...KC DISCUSSION...KC EXTENDED...KF AVIATION...KF MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
532 AM EST SAT DEC 31 2011 .SYNOPSIS... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW PATTERN OVER NAMERICA. THERE IS A NEAR ZONAL NRN BRANCH FLOW ACRS SRN CAN WITH A DISTURBANCE OF NOTE MOVING E THRU SASKATCHEWAN. OF NOTE THERE IS ALMOST A COMPLETE ABSENCE OF ARCTIC AIR IN THIS AREA...WITH THE LOWEST 00Z H85 TEMP ONLY -9C IN NRN BRITISH COLUMBIA. A MORE ACTIVE SRN BRANCH FLOW IS PRESENT IN THE CONUS. A FAIRLY DEEP TROF IS NOTED OVER THE GREAT LKS INTO THE OH RIVER VALLEY...SUPPORTING A SFC LO IN OH THAT IS MOVING E. UNDER AN UPR RDG IN THE CNTRL PLAINS...12Z-24Z H3 RISES OVER 200M ARE PRESENT... BUT THERE IS ONLY A WEAK SFC HI PRES RDG STRETCHING FM MN INTO WI ON THE NW FLANK OF THE SFC LO TO THE SE. LOCAL 00Z RAOBS SHOW SHARP SUBSIDENCE INVRN BTWN H875 AT GRB/APX AND H925 AT INL. THE SUB INVRN LYR IS RELATIVELY MOIST...SO LO CLDS ARE PRESENT OVER MUCH OF THE AREA. HOWEVER...THE LO CLDS HAVE DISSIPATED IN A SWATCH FM NE MN INTO NCNTRL WI AND OVER PARTS OF SCNTRL UPR MI. TEMPS IN THESE AREAS HAVE FALLEN AS LO AS 5 TO 10F. LOOKING FARTHER W...A VIGOROUS SHRTWV IS PLOWING THRU THE PAC NW...ACCOMPANIED BY 12Z-24Z H3 FALLS OVER 200M. RIGHT IN THE PATH OF THIS DISTURBANCE...A LINE OF SVR TS ACCOMPANIED BY SN STRUCK NEAR BOISE ID. && .DISCUSSION... MAIN FCST CONCERNS THIS PACKAGE FOCUS ON DETAILS OF UPCOMING SN STORM THAT IS FCST WITH DEVELOPMENT OF DEEP LO PRES SOMEWHERE NEAR UPR MI BY SUN. TDAY...A RELATIVELY QUIET PERIOD IS ON TAP FOR TODAY AS UPR RDG IN THE PLAINS DRIFTS E ACRS THE UPR LKS. WITH STRONGER SUBSIDENCE AHEAD OF THIS RDG...SUSPECT THE LO CLDS MAY BREAK UP A BIT EARLY THIS MRNG...UNLESS THE INVRN JUST SHARPENS AND CONTINUES TO TRAP THE LLVL MSTR. THE LO CLDS ARE LIKELY TO BE THE MOST RESILIENT OVER THE E NEAR LINGERING WEAK LO PRES TROF. THEN...NRN BRANCH SHRTWV IS FCST TO MOVE TO NEAR LK WINNIPEG WHILE THE STRONGER SRN BRANCH DISTURBANCE DIGS TO NEAR OMAHA BY 00Z SUN. THE STRENGTHENING SW FLOW AHEAD OF THESE FEATURES WL BRING MAINLY MID/HI CLDS INTO THE AREA WITH VERY DRY AT H85 LINGERING THRU THE DAY. MOST MODELS NOW GENERATE LTL OF NO PCPN OVER THE CWA THRU 00Z...SO RESTRICTED POPS TO THE FAR W CLOSER TO THE DEEPER MSTR FCST OVER MN/WRN LK SUP. EXPECT THE HIEST TEMPS INTO THE 30S OVER THE W NEAR LK SUP WHERE S WIND DOWNSLOPES. SINCE NAM WBLB ZERO HGT IS FCST TO BE AOA 1K FT IN THIS AREA OVER THE W...INCLUDED A MENTION OF RA/SN MIX WITH THE LGT PCPN EVEN THOUGH THE DRY AIR AT H85 WL TEND TO BRING ABOUT SOME EVAP COOLING. TNGT...THERE CONTINUES TO BE A LARGE SPREAD ON HOW QUICKLY THE SFC LO DEEPENS IN ASSOCIATION WITH MAINLY THE VIGOROUS SRN BRANCH DISTURBANCE NOW MOVING TOWARD THE NRN ROCKIES. CONSIDERING THE LACK OF ARCTIC AIR IN CAN AND THE SEPARATE BRANCHES OF FLOW OVER NAMERICA...NCEP FAVORS TRENDING AWAY FM THE CONSISTENTLY DEEPER GFS SCENARIO...WITH A BLEND OF THE 00Z NAM AND THE CONSISTENTLY WEAKER 12Z ECMWF. WHILE THE NRN BRANCH FEATURES DRIFT E THRU ONTARIO...THE 2 FAVORED MODELS SHOW THE SFC LO ASSOCIATED WITH THE SRN BRANCH SHRTWV REACHING NRN LK MI BY 12Z SUN...WITH NAM/ECMWF INTENSITY DOWN TO 993MB/999MB. EXPECT PCPN TO OVERSPREAD THE CWA W-E UNDER DPVA/UPR DVGC RELATED TO 12HR H5 FALLS UP TO 200M AND THE ARRIVAL OF MORE LLVL MSTR. SHARER H85-7 FGEN RELATED TO THE PASSAGE OF THE COLD FNT ASSOCIATED WITH THE NRN BRANCH DISTURBANCE/DEEPENING SRN BRANCH LO IS FCST TO ARRIVE AFT 06Z...SO EXPECT HIER POPS THEN. GRADUAL ARRIVAL OF COLDER AIR...H85 TEMPS ARE PROGGED TO FALL TO -8 TO -9C NEAR IWD BY 12Z SUN AS NRN BRANCH DISTURBANCE TAPS COLDER H85 AIR IN WRN CAN...WITH NW H85 FLOW IN THE PRESENCE OF DEEPER MSTR WL BRING SOME LK ENHANCED SN THERE. ALTHOUGH THE PCPN MAY BE MIXED WITH RA AT THE ONSET...THE COMBINATION OF DYNAMIC/EVAP COOLING WL CHANGE THE PCPN TO MAINLY SN FAIRLY QUICKLY EXCEPT NEAR THE LK MI SHORE. SUN/SUN NGT...AS THE NRN BRANCH DISTURBANCE GRADUALLY PHASES WITH THE SRN BRANCH SHRTWV...THE SFC LO IS FCST TO DEEPEN TO THE E OF UPR MI...MORE SLOWLY BY THE ECMWF TO 992MB...VS 989MB FOR THE NAM BY 00Z MON. BOTH MODELS SHOW THE LO DEEPENING TO ARND 987MB OVER WRN QUEBEC BY 12Z MON. COLDER AIR IS GRADUALLY ADVECTED INTO THE UPR GRT LKS... WITH H85 TEMPS PROGGED TO FALL TO -13C/-15C BY 00Z MON OVER WRN LK SUP AS H85 NW WINDS INCRS TO 40-50KTS IN THE WAKE OF THE LO TO THE E. THIS FLOW TENDS TO VEER MORE NNW ON SUN NGT FOLLOWING WHAT APPEARS TO THE PASSAGE OF THE ORIGINAL NRN BRANCH SHRTWV. THE ECMWF FCSTS H85 TEMPS SINKING AS LO AS -19C AT 12Z MON FOLLOWING THIS PASSAGE. ALTHOUGH BOTH THE NAM AND ECWMF...ESPECIALLY THE ECMWF... SHOW SOME DRIER AIR IN THE MID LVLS IMPACTING THE FAR W FOR A TIME ON SUN AS THE DEEPER QVECTOR CNVGC AND UPR DVGC LIFT AWAY TO THE ENE...THE COMBINATION OF LLVL CYC FLOW/DEEP MSTR IMPACT THE CWA THRU THIS TIME. THE ARRIVAL OF THE COLDER AIR WL ALSO TEND TO INCRS WIND SPEEDS...RESULTING IN CONSIDERABLE BLSN AS WELL AS THE LK ENHANCED SN WITH CONSIDERABLE OMEGA WITHIN THE DGZ. EXPECT NO MORE THAN SCT -SHSN OVER THE SCNTRL WITH DOWNSLOPE WIND...BUT SOME BLOWING SN IS LIKELY EVEN THERE...ESPECIALLY IN AREAS THAT PICK UP A FEW INCHES TNGT. MON/MON NGT...A NNW FLOW OF COLD AIR WL PERSIST THRU THIS TIME WITHIN H85 THERMAL TROF AND TEMPS FALLING NEAR -20C PER THE 12Z ECMWF. HOWEVER...AS THE CLOSED LO TO THE E EXITS FARTHER AWAY... MODELS IN GOOD AGREEMENT SHOWING DEEPER MSTR EXITING/INVRN BASE SUBSIDING W-E ON MON WITH THE ONSET OF DNVA/LARGE SCALE QVECTOR DVGC/SUBSIDENCE UNDER H5 RISES UP TO 180M AT IWD BTWN 18Z MON AND 06Z TUE. SO SHSN INTENSITY SHOULD DIMINISH W-E...BUT BE MORE RESILIENT OVER THE E WITH LONGER DURATION OF NLY FLOW/LOWER HGTS/ LOWER H85 TEMPS. WITH WEAKENING PRES GRADIENT...EXPECT THE BLSN TO SLOWLY SUBSIDE W-E AS WELL. SINCE SKIES WL LIKELY CLEAR MON NGT OVER AT LEAST THE W HALF...TENDED TO GO QUITE A BIT LOWER FOR MIN TEMPS WITH SFC RDG AXIS/LGT WINDS ARRIVING AND PWAT UNDER 50 PCT OF NORMAL. AS FAR AS HEADLINES ARE CONCERNED...OPTED TO UPGRADE WATCHES TO WRNGS OVER THE W HALF WHERE SGFNT SN WL BE FALLING IN THE 2ND PERIOD AND POSSIBLY IMPACT NEW YEARS EVE CELEBRATIONS. OPTED TO KEEP WATCH GOING FOR AREAS E OF MQT AS THE SGNFT WX WL NOT DEVELOP UNTIL THE 3RD PERIOD. THE BLIZZARD WATCH FOR THE NW ZNS THAT BEGAN AT 06Z PRESENTED A QUANDARY BECAUSE THE WX TNGT WL NOT MEET BLIZZARD CRITERIA FM WHEN THE ACCUMULATING SN WL ARRIVE ARND 03Z THRU AT LEAST 12Z SUN. SO OPTED TO GO WITH A WINTER STORM WRNG THERE. SINCE BLIZZARD CONDITIONS ARE LIKELY ON SUN/MON...LATER SHIFTS WL LIKELY NEED TO UPGRADE THE WRNG TO A BLIZZARD. DID HIGHLIGHT THE ONSET OF BLIZZARD CONDITONS ON SUN IN THE STATEMENT. THE WATCH FOR E OF MQT MAY ALSO NEED TO BE UPGRADED TO A BLIZZARD WRNG AT SOME TIME WITH SHSN/WIND GUSTS UP TO 60 MPH/EXTENSIVE BLOWING SN LIKELY THERE SUN AFTN INTO MON NGT. FOR THE EXTENDED FORECAST... FEW CHANGES WERE DEEMED NECESSARY...AS THE FORECAST REMAINED A BLEND OF AVAILABLE MODEL DATA. STARTING AT 12Z TUESDAY THE 500MB MAP SHOWS THE DEEP TROUGH SET UP OVER THE LOWER GREAT LAKES AND NEW ENGLAND STATES...WITH A SIGNIFICANT RIDGE BUILDING OVERHEAD. THE 500MB RIDGE WILL BECOME SUPPRESSED TUESDAY NIGHT...IN RESPONSE TO A OPEN WAVE SNEAKING IN FROM THE WEST. THE 00Z RUNS OF THE CANADIAN/ECMWF AND GFS ALL HAVE THIS FEATURE...WITH MINOR DIFFERENCES. THE 31/00Z RUN OF THE ECMWF TRIES TO CLOSE THIS FEATURE OFF ACROSS LAKE SUPERIOR AT 06Z WEDNESDAY...BEFORE IT SINKS TO THE LOWER GREAT LAKES. THE CANADIAN IS SIMILAR...BUT APPROX 250MI NW OF THE ECMWF WITH THIS FEATURE. THE RESULT IS A MORE PROGRESSIVE GFS. THIS SHOWS UP AT THE SFC TOO...WITH THE COLD FRONT/TROUGH OFF THE GFS SPLITTING THE CWA IN HALF AT 06Z WEDNESDAY. THE ECMWF IS CLOSER TO 12Z WEDNESDAY. STILL...MOST MODELS DO INDICATE RIDGING ALOFT AGAIN FOR WEDNESDAY THROUGH THE DAY FRIDAY. THE EXCEPTION TO THIS IS THE SLOWER CANADIAN RUN...WHICH STRENGTHENS THE 500MB LOW ACROSS QUEBEC AND LEADS TO A SLOW DOWN WHEN COMPARED TO THE OTHER MODELS OF AROUND 6HRS. THE NEXT FEATURE OF INTEREST AT THE SFC LOOKS TO BE OVER S CENTRAL CANADA FRIDAY MORNING...AND MAY CROSS OVER OR JUST NORTH OF LAKE SUPERIOR FRIDAY AFTERNOON/EVENING. WILL NOT CONCENTRATE OF THIS NEXT SYSTEM...DUE TO THE MODERATE CONFIDENCE. && .AVIATION /FOR THE 06Z TAF ISSUANCE/... LIGHT/VRB WIND REGIME WILL BECOME SOUTHERLY OVERNIGHT INTO THE MORNING HRS. AS IT DOES...LOWER CLOUDS (MAINLY MVFR) AT KIWD/KCMX/KSAW WILL SCATTER OUT WITH VFR CONDITIONS THEN FOLLOWING THRU THE DAY. BEFORE THAT HAPPENS...THERE ARE CURRENTLY LOWER IFR CIGS TRYING TO SPREAD W FROM ERN UPPER MI. THESE CLOUDS MAY REACH KSAW...SO HAVE INCLUDED AN IFR CIG INTO THE EARLY MORNING HRS. ALSO...WHERE CLOUDS SCATTER OUT FOR A WHILE...FOG MAY DEVELOP AND POTENTIALLY DROP VIS TO IFR OR LOWER. WITH LOW CONFIDENCE IN DENSE FOG DEVELOPMENT...DID NOT DROP VIS BLO MVFR. NEXT LOW PRES SYSTEM ORGANIZING OVER THE CNTRL/NRN PLAINS TODAY WILL DEEPEN AS IT TRACKS ACROSS THE UPPER GREAT LAKES TONIGHT/EARLY SUN. INCREASING WIND FIELDS WILL RESULT IN A PERIOD OF LLWS AT KCMX IN THE EVENING. SFC WINDS SHOULD REMAIN GUSTY AT KIWD/KSAW...SO DID NOT INCLUDE LLWS AT THOSE SITES. SNOW WILL SPREAD TO KIWD/KCMX MID TO LATE EVENING WITH CONDITIONS QUICKLY FALLING TO IFR. OUTLOOK...DEEPENING LOW PRES WILL PASS ACROSS THE UPPER GREAT LAKES LATE TONIGHT/SUN MORNING. DUE TO STRONG NORTHWESTERLY WINDS AND MDT/HEAVY LAKE EFFECT SNOW BEHIND THE LOW...FLYING CONDITIONS ARE EXPECTED TO BECOME VERY POOR NEW YEARS DAY. ADVERSE CONDITIONS... PROBABLY AT OR BLO AIRPORT MINS AT KCMX...SHOULD CONTINUE INTO MON. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... LOWER GREAT LAKES LOW PRESSURE WILL EXIT TO THE NEW ENGLAND SEABOARD TODAY. IN ITS WAKE...LOW PRESSURE STRETCHING FROM WESTERN MANITOBA THROUGH THE DAKOTAS CAN BE EXPECTED TO DEEPEN NEAR NORTHERN LM SUNDAY MORNING...BEFORE SHIFTING ACROSS QUEBEC MONDAY...WHILE KEEPING A SIGNIFICANT TROUGH ACROSS LS AND UPPER MI. AHEAD OF STRONG HIGH PRESSURE OVER THE PLAINS STATES MONDAY MORNING WORKING A RIDGE WEST TO EAST ACROSS LS TUESDAY...STRONG N TO NW STORM FORCE WINDS LIKELY CENTRAL AND EAST SUNDAY AFTERNOON THROUGH MONDAY. THE RUSH OF COLD AIR AND HIGH WAVES WILL RESULT IN PERIODS OF MODERATE TO HEAVY FREEZING SPRAY AS WELL. A LOW PRESSURE SYSTEM OVER CENTRAL CANADA TUESDAY AFTERNOON WILL SHIFT SOUTHEASTWARD INTO HUDSON BAY...DRAGGING A TROUGH OVER THE UPPER GREAT LAKES ON WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER STORM WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 7 PM EST /6 PM CST/ MONDAY FOR MIZ001>003-009-084. WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT FOR MIZ006-007-085. WINTER STORM WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY FOR MIZ004-005. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST MONDAY FOR MIZ010. LAKE SUPERIOR... STORM WARNING FROM 7 AM SUNDAY TO 10 PM EST MONDAY FOR LSZ264>267. HEAVY FREEZING SPRAY WATCH FROM SUNDAY EVENING THROUGH TUESDAY MORNING FOR LSZ162-263>267. STORM WARNING FROM 11 AM SUNDAY TO 10 PM EST MONDAY FOR LSZ248>251. STORM WARNING FROM 11 AM SUNDAY TO 4 PM EST MONDAY FOR LSZ243>247. STORM WARNING FROM 11 AM EST /10 AM CST/ SUNDAY TO 7 AM EST /6 AM CST/ MONDAY FOR LSZ241-242. GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 11 AM EST /10 AM CST/ MONDAY FOR LSZ240. GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 1 PM EST /NOON CST/ MONDAY FOR LSZ162. STORM WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ263. LAKE MICHIGAN... GALE WARNING FROM 5 AM SUNDAY TO 1 AM EST TUESDAY FOR LMZ221-248- 250. && $$ SYNOPSIS...KC DISCUSSION...KC EXTENDED...KF AVIATION...ROLFSON MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1000 AM CST SAT DEC 31 2011 .DISCUSSION... PRECIP BAND CURRENTLY EXTENDING FROM NORTHERN RED VALLEY INTO THE SOUTHERN SHEYENNE VALLEY. PRECIP TYPE IS ALL OVER THE PLACE...WITH REPORTS COMING IN OF A MIX OF MAINLY FZRA AND SN WITH A FEW IP THROWN IN. THE MODELS...BOTH THE HRRR AND 12Z NAM...HAVE THE PRECIP FURTHER WEST THAN RADAR SHOWS. CUT POPS QUITE A BIT IN THE DEVILS LAKE BASIN AND WILL DROP THE ADVISORY IN THAT AREA. DO NOT THINK WE WILL GET MUCH SNOW ACCUMULATION IN THE REST OF THE ADVISORY AREA...BUT WILL CONTINUE THE HEADLINE UNTIL IT EXPIRES AT NOON TO ALERT PEOPLE TO FZRA/SN CHANCES. AFTER NOON...PRECIP BAND SHOULD WEAKEN AND MOVE FURTHER EAST. A FURTHER DUSTING OF SNOW IS POSSIBLE MAINLY IN MN...WITH SOME RAIN MIXING IN OVER THE SOUTHERN COUNTIES WHICH ARE HOVERING NEAR THE FREEZING MARK AT THIS TIME AND COULD BE A FEW DEGREES WARMER BY AFTERNOON. WILL CONTINUE TO KEEP HIGHS WHAT WE HAVE GOING FOR TODAY...AS THERE SEEMS TO BE SOME DECENT WARMING ALONG THE PRE-FRONTAL TROUGH IN WESTERN ND. THE TRUE COLD AIR SEEMS LIKE IT WILL HOLD OFF UNTIL TONIGHT. && .AVIATION... CEILINGS ARE RANGING FROM LIFR TO VFR ACROSS THE AREA THIS MORNING. VIS IN SNOW BANDS HAS GONE DOWN BELOW A MILE AT TIMES...BUT THE PRECIP WILL MOVE OUT QUICKLY AND VIS SHOULD RECOVER. THE PRECIP WILL MOVE EASTWARD INTO KTVF AND KBJI THIS AFTERNOON...WHILE KDVL WILL CONTINUE TO BE VFR UNTIL NORTHWESTERLY WINDS PICK UP TONIGHT. THE WINDS WILL BRING SOME REDUCTION TO VIS DUE TO BLSN OVERNIGHT MAINLY AT KDVL AND KGFK. && .PREV DISCUSSION... /ISSUED 254 AM CST SAT DEC 31 2011/ DISCUSSION...FORECAST CHALLENGE WILL BE PCPN AMOUNTS/PHASE...TEMPERATURES AND WIND/BLSN POTENTIAL TONIGHT INTO SUNDAY AND RELATED HEADLINES TO ALL. MODELS FAIRLY CLOSE AND WILL USE BLEND. CHALLENGING FORECAST IN THE SHORT TERM TO SAY THE LEAST. BROAD LOW PRESSURE OVER THE NORTHERN HIGH PLAINS WILL ORGANIZE WITH SURFACE LOWS TRACKING ACROSS SOUTHERN CANADIAN PRAIRIE PROVINCES AND ACROSS SD TODAY. THERMAL PROFILES CURRENTLY VERY WARM WHERE PCPN IS OCCURRING TO OUR WEST. COLUMN BEGINS TO COOL AS PCPN MOVES FIRST INTO DVL BASIN AND THEN EASTWARD DURING THE DAY. JUST HOW FAST COLUMN COOLS TO SWITCH TO SNOW BIG QUESTION AND UNSURE AT THIS POINT. MODEL SOUNDINGS INDICATING POTENTIAL FOR MIXED BAG OF PCPN PHASES. COULD INITIALLY SEE SOME ZR-/FZDZ WITH GFS SHOWING GOOD SNOW PROFILE BY 18Z ACROSS NORTH HALF. HOW FAR TEMPERATURES WARM WITH PREFRONTAL TROUGH PASSAGE ALSO A CHALLENGE AND COULD AFFECT DEGREE OF ZR POTENTIAL. UPSTREAM TEMPERATURES ALONG BOUNDARY IN THE MID- UPPER 30S AND COULD SEE ABOVE FREEZING TEMPERATURES HERE. FOR THE MORNING WILL MAINTAIN ZR/S...S ACROSS NORTH THIS AFTERNOON WITH -RASN ACROSS SOUTH WHERE LESS SNOW COVER AND WARMER START SHOULD ALLOW FOR BETTER CHANCES TO GET ABOVE FREEZING. BASED ON CURRENT PCPN LOCATION AND MODEL TRENDS WILL NEED TO BACK HIGHER POPS FARTHER WEST DURING THE DAY. OVERALL EXPECTING GENERAL 1 TO 3 INCHES OF SNOW POSSIBLY A LITTLE MORE OVER THE FAR NE. AT THIS POINT WILL BE HOLDING OFF ON WINTER WX/FREEZING RAIN ADVISORY AND MONITOR OBSERVATIONS THROUGH THE EARLY MORNING. CHALLENGE TONIGHT WILL BE BLSN/BLIZZARD POTENTIAL. FAIRLY LOW CONFIDENCE AT THIS POINT ON TRUE BLIZZARD CONDITIONS FOR SEVERAL REASONS. FOR THE MOST PART PCPN SHOULD BE DONE WHEN STRONGER WINDS ARRIVE THIS EVENING. SNOW COVER FRESH BUT NOT PARTICULARLY DEEP. HOW MUCH IF ANY FREEZING RAIN OCCURS AND HOW LONG TEMPERATURES GET ABOVE FREEZING WILL DETERMINE CRUSTING OF WHAT SNOW THERE IS. STRONG WINDS ALOFT...40 TO 50KTS HOWEVER THERE WILL BE AN INVERSION OF SOME DEGREE TO OVERCOME. BEST PUSH OF LOW LEVEL COLD ADVECTION WILL BE AHEAD OF STRONGER WINDS WITH MODELS INDICATING WARM ADVECTION TOWARDS 06Z. WITH WINDS OCCURRING AT NIGHT AND ABOVE THINKING NOT SURE IF STRONGER WINDS WILL BE ABLE TO PUNCH DOWN TO THE SURFACE. DVL BASIN LIKELY TO SEE BEST CHANCES FOR STRONGEST WINDS WITH HIGHER ELEVATION AND MORE SNOW. FARTHER EAST INTO THE VALLEY W-NW WIND DIRECTION AND POTENTIAL INVERSION WILL MAKE IT TOUGHER FOR STRONGER WINDS TO WORK DOWN. SOUTHERN HALF OF VALLEY HAS VERY LITTLE SNOW SO BLSN WILL BE LIKELY CONFINED TO PATCHY RESTRICTED VSBY IN OPEN AREAS. WITH IT BEING A HOLIDAY WEEKEND WILL ISSUE BLIZZARD WATCH FOR DVL BASIN AND LATER SHIFTS CAN ADJUST BASED ON WHAT OCCURS TODAY. WINDY CONDITIONS WILL CONTINUE THROUGH NEW YEARS DAY. ANY -SHSN LOOKS TO BE CONFINED TO AREAS MAINLY EAST OF THE VALLEY. WILL LIKELY SEE CONTINUED BLSN IN OPEN AREAS ACROSS DVL BASIN INTO NORTHERN VALLEY AND ADJACENT NW MN. COLD ADVECTION AND NOW SNOW WILL LIMIT TEMPERATURE RECOVER. FAR SOUTH WITH LESS SNOW WILL HAVE BEST CHANCE FOR RECOVERY. THINGS QUIET DOWN SUNDAY NIGHT INTO EARLY NEXT WEEK AS HIGH PRESSURE BUILDS IN. WITH SOME SNOW MOST AREAS AND THERMAL PROFILE LOOK FOR MORE WINTER TIME TEMPERATURE TRENDS. LONG TERM (TUESDAY-FRIDAY)...GFS/ECMWF IN DECENT AGREEMENT WITH PATTERN. WEAK SYSTEM WILL CLIP THE NORTHERN FA ON TUESDAY...THEN UPPER RIDGE BUILDS ACROSS THE WESTERN CONUS AND STORM TRACK ONCE AGAIN SHOULD BE NORTH OF THE INTERNATIONAL BORDER. TEMPERATURES SHOULD BE WELL ABOVE NORMAL...WITH SNOW AND CLOUD COVER DETERMINING ACTUAL VALUES. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR NDZ008-016- 026>030-038-039-049-052. BLIZZARD WATCH FROM 6 PM CST THIS EVENING THROUGH SUNDAY MORNING FOR NDZ006-007-014-015-024-026-054. MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ001>005-007- 008. && $$ JR
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
945 AM CST SAT DEC 31 2011 .DISCUSSION.../ISSUED AT 945 AM CST/ LATEST RUC...NAM AND HRRR MORE IN AGREEMENT WITH PRECIPITATION DEVELOPING DURING TEH AFTERNOON...ESPECIALLY ALONG AND EAST OF INTERSTATE 29 ALONG AXIS OF STRONG H85 FRONTALGENESIS...WITH VERY LITTLE PRECIPITATION TO THE WEST. CURRENT RADAR TRENDS SEEM TO VALIDATE THIS SCENARIO AND WILL TRIM BACK POPS WEST OF JAMES VALLEY AND INCREASE POPS ALONG I29 CORRIDOR FOR FSD-SUX WHERE POPS WERE ONLY AROUND 70%. SHOULD START AS RAIN AND THEN SWITCH TO SNOW BY LATE AFTERNOON AS LAYER COOLS DUE TO STRONG LIFT AND EVAPORATION. COULD SEE A QUIKC INCH OF SNOW ALONG I29 WITH 1 TO 3 INCHES FURTHER EAST. WILL ADD ANOTHER ROW OF COUNTIES TO WINTER WEATHER ADVISORY OVER NORTHWEST IOWA. FINALLY...EXPECT THE STRONG WILL TO SPREAD ACROSS CWA THIS AFTERNOON INTO EARLY EVENING BEHIND COLD FRONT. FOR NOW WILL NOT UPGRADE FAR WEST TO HIGH WIND WARNING...AS CRITERIA MAY ONLY BE MET FOR AN HOUR OR TWO. SO WIND ADVISORY ACROSS THE CWA LOOKS MORE REASONABLE. && .AVIATION.../FOR THE 12Z TAF ISSUANCE/ A BAND OF RAIN WILL DEVELOP AROUND 18Z NEAR THE JAMES RIVER VALLEY...THEN PROGRESS EAST THROUGH THE AFTERNOON. THE RAIN SHOULD CHANGE TO SNOW AROUND INTERSTATE 29 AFTER ABOUT 23Z WITH SOME ACCUMULATIONS LIKELY ALONG AND EAST OF INTERSTATE 29. BECAUSE OF THE VERY STRONG NORTHWEST WINDS THAT WILL DEVELOP THROUGH THE DAY SOME REDUCTION OF VISIBILITY WILL BE LIKELY WITH BLOWING SNOW...ESPECIALLY EAST OF INTERSTATE 29...POSSIBLY INTO THE IFR CATEGORY AT TIMES. OTHERWISE...NORTHWEST WINDS WILL GUST TO AROUND 45 MPH IN MOST LOCATIONS FROM LATE THIS MORNING INTO THE EVENING...DECREASING ONLY SLIGHTLY OVERNIGHT INTO SUNDAY MORNING. CEILINGS SHOULD MAINLY STAY IN THE VFR CATEGORY ALTHOUGH SOME BRIEF MVFR CEILINGS WILL BE POSSIBLE WITHIN THE RAIN AND SNOW BAND. /08 && .PREVIOUS DISCUSSION.../ISSUED AT 400 AM CST/ MAIN FOCUS OF THIS PACKAGE IS THE POTENTIAL FOR SNOW AND WIND LATER TODAY AND TONIGHT...ESPECIALLY ACROSS SOUTHWEST MINNESOTA AND INTO NORTHWEST IOWA. AT 09Z...LOWS PRESSURE WAS LOCATED OVER SOUTHEAST MONTANA. THE STRENGTHENING GRADIENT HAS RESULTED IN INCREASING SOUTHEAST FLOW ACROSS MUCH OF THE AREA WITH TEMPERATURES REMAINING NEAR FREEZING. AS THE LOW RAPIDLY MOVES TO THE EAST...IT WILL DRAG A STRONG COLD FRONT ACROSS THE DAKOTAS AND NEBRASKA THIS MORNING...AND SOUTHWEST MINNESOTA AND NORTHWEST IOWA THIS AFTERNOON. BEHIND THE SURFACE FRONT...WINDS WILL RAPIDLY INCREASE WITH SUSTAINED WINDS LIKELY TO EXCEED 30 MPH BY LATE AFTERNOON...ESPECIALLY IN THE MISSOURI VALLEY. WOULD NOT BE SURPRISED IF SOME AREAS IN THE MISSOURI VALLEY SEE GUSTS TO 50 MPH LATE THIS AFTERNOON. STRONG 700 MB FRONTOGENESIS WILL FOLLOW THE PASSAGE OF THE SURFACE FRONT. ACCOMPANYING THIS AREA OF MID-LEVEL FRONTOGENESIS...A VERY STRONG PV ANOMALY WILL MOVE ACROSS THE DAKOTAS. A LINE OF LIGHT PRECIPITATION IS EXPECTED TO DEVELOP AS THE UPPER LEVEL ANOMALY INTERACTS WITH THE 700 MB FRONT. FOR NOW...EXPECTING THAT THIS PRECIPITATION WILL BEGIN AS RAIN IN THE JAMES AND MISSOURI VALLEYS AS WET BULB TEMPERATURE REMAIN BARELY ABOVE FREEZING. HOWEVER...IF COLDER AIR FOLLOWS MORE QUICKLY BEHIND THE SURFACE MAY SEE A MIX WITH SNOW EVEN AS FAR WEST AS HURON AND MITCHELL. PRECIPITATION AMOUNTS IN THE JAMES VALLEY ARE EXPECTED TO BE AROUND A TENTH OF AN INCH. AS PV ANOMALY MOVES INTO WRN IOWA...IT WILL CYCLONICALLY WRAP-UP. THIS WILL INTENSIFY THE 700 MB FRONT AS IT MOVES TOWARD I-29 AND EXPECTATION IS THAT THE PRECIPITATION BAND WILL BECOME MORE INTENSE AND ORGANIZED LATE THIS AFTERNOON AND THIS EVENING. IN ADDITION...WITH HIGHER PRECIPITATION RATES AND COLDER AIR WORKING IN...IT IS EXPECTED PRECIPITATION WILL BEGIN TO MIX WITH OR CHANGE TO SNOW TOWARD I-29 AND ESPECIALLY INTO SW MN AND NW IA AFTER 00Z. THERE IS EXPECTED TO BE AN AREA OF 1 TO 3 INCHES OF SNOW OVER MUCH OF SW MN AND ALONG HIGHWAY 71 IN NORTHWEST IOWA INCLUDING SPENCER AND STORM LAKE. WITH THE SNOWFALL...WILL BE SUSTAINED WINDS OVER 30 MPH WITH GUSTS APPROACHING 50 MPH. EVEN WITH NO SNOW CURRENTLY ON THE GROUND...THE COMBINATION OF FALLING AND ACCUMULATING SNOW WILL QUICKLY PRODUCE WIDESPREAD BLOWING SNOW...ESPECIALLY THIS EVENING...WHICH WILL REDUCE VISIBILITIES BELOW A HALF MILE. THEREFORE HAVE ISSUED A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW FROM 4 PM TO MIDNIGHT. EVEN WHERE NO ADVISORY IS IN EFFECT...SUCH AS AROUND SIOUX FALLS...CHEROKEE...AND SHELDON...BRIEF PERIODS OF LOW VISIBILITIES CAN BE EXPECTED WHEN SNOW IS FALLING LATE THIS AFTERNOON AND EARLY THIS EVENING. BECAUSE OF THE RAPID INTENSIFICATION OF THE UPPER LEVEL WAVE...CONFIDENCE IN THE EXACT AREA OF SNOWFALL REMAINS UNCERTAIN. THERE ARE TWO CONCERNS...FIRST PRECIPITATION SWITCHES MORE QUICKLY TO SNOW SO THAT SOME AREAS SEE IN EXCESS OF 3 INCHES OF SNOW...WHICH WOULD BE ENOUGH TO PRODUCE BLIZZARD CONDITIONS IN OPEN AREAS WITH THE EXPECTED WINDS. SECOND...HEAVIER SNOWFALL OF 1 TO 3 INCHES COULD EXTEND FARTHER WEST INCLUDING I-29 OR EVEN AS FAR WEST AS HIGHWAY 81 WHICH WOULD AFFECT YANKTON...BROOKINGS...SIOUX FALLS AND EVEN SIOUX CITY. PERSONS PLANNING TRAVEL LATER THIS AFTERNOON AND TONIGHT SHOULD MONITOR FORECASTS. AFTER THE SNOW ENDS...COULD SEE BLOWING SNOW THE REMAINDER OF THE NIGHT IN SW MN AND NW IA. OTHERWISE...WINDS OF 20 TO 40 MPH ARE EXPECTED. THIS WILL KEEP THE ATMOSPHERE WELL MIXED SO LOWS WILL REMAIN IN THE 20S. WINDY CONDITIONS WILL CONTINUE THROUGH SUNDAY WITH LITTLE WARMING. MOST PLACES WILL SEE HIGHS FROM THE MID 20S TO THE LOWER 30S. THE WINDS ARE EXPECTED TO REMAIN OVER 30 MPH IN SW MN AND NW IA INTO SUNDAY SO EXTENDED THE WIND ADVISORY INTO SUNDAY. WITH COLD AIR CONTINUING TO FILTER IN...LOWS WILL BE IN THE TEENS. MONDAY WILL SEE A RIDGE MOVE OVER THE AREA. WITH LIMITED MIXING AND SOME SNOW COVER EXPECTED IN OUR ERN CWA...HIGHS IN SW MN AND NW IOWA WILL STAY IN THE MID 20S. FARTHER WEST...WARM AIR WILL BEGIN TO MOVE IN AND TEMPERATURES WILL RISE INTO THE LOWER 30S. AS THE RIDGE MOVES OVER THE AREA MONDAY NIGHT...EXPECT SOME RADIATION COOLING...ESPECIALLY ALONG AND EAST OF I29 AND LOWER MINS TO AROUND 10 ABOVE. ALONG AND WEST OF THE JAMES RIVER...INCREASING SOUTH WINDS WILL KEEP LOWS IN THE TEENS. A WARMING TREND CAN BE EXPECTED FOR THE REMAINDER OF THE WEEK WITH NEAR RECORD TEMPERATURES POSSIBLE BY THURSDAY. NO PRECIPITATION IS EXPECTED. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR IAZ001-012-020-031. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR IAZ002-003-013-014-021-022-032. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY NIGHT FOR IAZ002-003-013-014-021-022-032. MN...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR MNZ098. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR MNZ071-072-080-081-089-090. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY NIGHT FOR MNZ071-072-080-081-089-090-097. NE...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR NEZ013-014. SD...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ038>040-052>056- 058>062-064>071. WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ050-057-063. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
405 AM CST SAT DEC 31 2011 .DISCUSSION.../ISSUED AT 400 AM CST/ MAIN FOCUS OF THIS PACKAGE IS THE POTENTIAL FOR SNOW AND WIND LATER TODAY AND TONIGHT...ESPECIALLY ACROSS SOUTHWEST MINNESOTA AND INTO NORTHWEST IOWA. AT 09Z...LOWS PRESSURE WAS LOCATED OVER SOUTHEAST MONTANA. THE STRENGTHENING GRADIENT HAS RESULTED IN INCREASING SOUTHEAST FLOW ACROSS MUCH OF THE AREA WITH TEMPERATURES REMAINING NEAR FREEZING. AS THE LOW RAPIDLY MOVES TO THE EAST...IT WILL DRAG A STRONG COLD FRONT ACROSS THE DAKOTAS AND NEBRASKA THIS MORNING...AND SOUTHWEST MINNESOTA AND NORTHWEST IOWA THIS AFTERNOON. BEHIND THE SURFACE FRONT...WINDS WILL RAPIDLY INCREASE WITH SUSTAINED WINDS LIKELY TO EXCEED 30 MPH BY LATE AFTERNOON...ESPECIALLY IN THE MISSOURI VALLEY. WOULD NOT BE SURPRISED IF SOME AREAS IN THE MISSOURI VALLEY SEE GUSTS TO 50 MPH LATE THIS AFTERNOON. STRONG 700 MB FRONTOGENESIS WILL FOLLOW THE PASSAGE OF THE SURFACE FRONT. ACCOMPANYING THIS AREA OF MID-LEVEL FRONTOGENESIS...A VERY STRONG PV ANOMALY WILL MOVE ACROSS THE DAKOTAS. A LINE OF LIGHT PRECIPITATION IS EXPECTED TO DEVELOP AS THE UPPER LEVEL ANOMALY INTERACTS WITH THE 700 MB FRONT. FOR NOW...EXPECTING THAT THIS PRECIPITATION WILL BEGIN AS RAIN IN THE JAMES AND MISSOURI VALLEYS AS WET BULB TEMPERATURE REMAIN BARELY ABOVE FREEZING. HOWEVER...IF COLDER AIR FOLLOWS MORE QUICKLY BEHIND THE SURFACE MAY SEE A MIX WITH SNOW EVEN AS FAR WEST AS HURON AND MITCHELL. PRECIPITATION AMOUNTS IN THE JAMES VALLEY ARE EXPECTED TO BE AROUND A TENTH OF AN INCH. AS PV ANOMALY MOES INTO WRN IOWA...IT WILL CYCLONICALLY WRAP-UP. THIS WILL INTENISIFY THE 700 MB FRONT AS IT MOVES TOWARD I-29 AND EXPECTATION IS THAT THE PRECIPITATION BAND WILL BECOME MORE INTENSE AND ORGANIZED LATE THIS AFTERNOON AND THIS EVENING. IN ADDITION...WITH HIGHER PRECIPITATION RATES AND COLDER AIR WORKING IN...IT IS EXPECTED PRECIPITATION WILL BEGIN TO MIX WITH OR CHANGE TO SNOW TOWARD I-29 AND ESPECIALLY INTO SW MN AND NW IA AFTER 00Z. THERE IS EXPECTED TO BE AN AREA OF 1 TO 3 INCHES OF SNOW OVER MUCH OF SW MN AND ALONG HIGHWAY 71 IN NORTHWEST IOWA INCLUDING SPENCER AND STORM LAKE. WITH THE SNOWFALL...WILL BE SUSTAINED WINDS OVER 30 MPH WITH GUSTS APPROACHING 50 MPH. EVEN WITH NO SNOW CURRENTLY ON THE GROUND...THE COMBINATION OF FALLING AND ACCUMULATING SNOW WILL QUICKLY PRODUCE WIDESPREAD BLOWING SNOW...ESPECIALLY THIS EVENING...WHICH WILL REDUCE VISIBILITIES BELOW A HALF MILE. THEREFORE HAVE ISSUED A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW FROM 4 PM TO MIDNIGHT. EVEN WHERE NO ADVISORY IS IN EFFECT...SUCH AS AROUND SIOUX FALLS...CHEROKEE...AND SHELDON...BRIEF PERIODS OF LOW VISIBILITIES CAN BE EXPECTED WHEN SNOW IS FALLING LATE THIS AFTERNOON AND EARLY THIS EVENING. BECAUSE OF THE RAPID INTENSIFICATION OF THE UPPER LEVEL WAVE...CONFIDENCE IN THE EXACT AREA OF SNOWFALL REMAINS UNCERTAIN. THERE ARE TWO CONCERNS...FIRST PRECIPTIATION SWITCHES MORE QUICKLY TO SNOW SO THAT SOME AREAS SEE IN EXCESS OF 3 INCHES OF SNOW...WHICH WOULD BE ENOUGH TO PRODUCE BLIZZARD CONDITIONS IN OPEN AREAS WITH THE EXPECTED WINDS. SECOND...HEAVIER SNOWFALL OF 1 TO 3 INCHES COULD EXTEND FARTHER WEST INCLUDING I-29 OR EVEN AS FAR WEST AS HIGHWAY 81 WHICH WOULD AFFECT YANKTON...BROOKINGS...SIOUX FALLS AND EVEN SIOUX CITY. PERSONS PLANNING TRAVEL LATER THIS AFTERNOON AND TONIGHT SHOULD MONITOR FORECASTS. AFTER THE SNOW ENDS...COULD SEE BLOWING SNOW THE REMAINDER OF THE NIGHT IN SW MN AND NW IA. OTHERWISE...WINDS OF 20 TO 40 MPH ARE EXPECTED. THIS WILL KEEP THE ATMSOSPHERE WELL MIXED SO LOWS WILL REMAIN IN THE 20S. WINDY CONDITIONS WILL CONTINUE THROUGH SUNDAY WITH LITTLE WARMING. MOST PLACES WILL SEE HIGHS FROM THE MID 20S TO THE LOWER 30S. THE WINDS ARE EXPECTED TO REMAIN OVER 30 MPH IN SW MN AND NW IA INTO SUNDAY SO EXTENDED THE WIND ADVISORY INTO SUNDAY. WITH COLD AIR CONTINUING TO FILTER IN...LOWS WILL BE IN THE TEENS. MONDAY WILL SEE A RIDGE MOVE OVER THE AREA. WITH LIMITED MIXING AND SOME SNOW COVER EXPECTED IN OUR ERN CWA...HIGHS IN SW MN AND NW IOWA WILL STAY IN THE MID 20S. FARTHER WEST...WARM AIR WILL BEGIN TO MOVE IN AND TEMPERATURES WILL RISE INTO THE LOWER 30S. AS THE RIDGE MOVES OVER THE AREA MONDAY NIGHT...EXPECT SOME RADIATION COOLING...ESPECIALLY ALONG AND EAST OF I29 AND LOWER MINS TO AROUND 10 ABOVE. ALONG AND WEST OF THE JAMES RIVER...INCREASING SOUTH WINDS WILL KEEP LOWS IN THE TEENS. A WARMING TREND CAN BE EXPECTED FOR THE REMAINDER OF THE WEEK WITH NEAR RECORD TEMPERATURES POSSIBLE BY THURSDAY. NO PRECIPITATION IS EXPECTED. && .AVIATION.../FOR THE 00Z TAF ISSUANCE/ IFR TO MVFR CEILINGS OVER TAF LOCATIONS WILL GRADUALLY AND I MEAN GRADUALLY SHIFT EAST PER RUC MOISTURE DATA. EXPECT VFR CONDITIONS AFTER 06Z. MAIN STORY WILL BE THE WINDS INCREASING AFTER FROPA ON SATURDAY. LOOKS LIKE RIGHT AROUND 17S FOR KHON...18Z KFSD...AND 19Z FOR KSUX. NORTHEAST WINDS TO INCREASE QUICKLY AFTER FROPA. && FSD WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY FROM NOON TODAY TO 6 PM CST SUNDAY FOR IAZ001-012- 020-031. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY NIGHT FOR IAZ002-003-013-014-021-022-032. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR IAZ003-014-022. MN...WIND ADVISORY FROM NOON TODAY TO 6 PM CST SUNDAY FOR MNZ098. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY NIGHT FOR MNZ071-072-080-081-089-090-097. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR MNZ071-072-080-081-089-090. NE...WIND ADVISORY FROM NOON TODAY TO 6 PM CST SUNDAY FOR NEZ013-014. SD...WIND ADVISORY FROM NOON TODAY TO 6 PM CST SUNDAY FOR SDZ038>040- 052>056-058>062-064>071. WIND ADVISORY FROM 9 AM THIS MORNING TO 6 PM CST SUNDAY FOR SDZ050-057-063. && $$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
515 AM CST SAT DEC 31 2011 .AVIATION... LOW CLOUDS/FOG PROGGED TO SHUNT NORTHEAST BEFORE IT REACHES WACO. LIFR/IFR CONDITIONS MAY PERSIST ALL DAY IN EASTERN NORTH TEXAS. HRRR SEEMS TO HAVE A GOOD HANDLE ON STRATUS AND WILL FOLLOW ITS GUIDANCE...SUPPORTED BY RUC SOUNDINGS AS WELL. COLD FRONT SHOULD REACH METROPLEX NEAR SUNDOWN...AND SHIFT WINDS BACK TO THE NORTH. LACK OF MOISTURE WILL PRODUCE CAVOK CONDITIONS WITH FROPA AND EXPECT CLEAR SKIES TO CONTINUE SUNDAY. 84 && .PREV DISCUSSION... /ISSUED 359 AM CST SAT DEC 31 2011/ LOW CLOUDS AND PATCHY FOG OVER SOUTHEAST TEXAS SHOULD SPREAD INTO THE SOUTHEASTERN PART OF NORTH TEXAS THIS MORNING. OTHERWISE...EXPECT A WARM AND MOSTLY SUNNY LAST DAY OF THE YEAR ACROSS NORTH TEXAS. AFTER MORNING LOWS IN THE 30S...TEMPERATURES WILL CLIMB INTO THE 70S AREA WIDE THIS AFTERNOON. A COLD FRONT THAT EXTENDED FROM CENTRAL SOUTH DAKOTA SOUTHWEST INTO THE NORTHERN COLORADO AT 3 AM... WILL SWEEP SOUTHEAST INTO THE WICHITA FALLS AREA BY SUNSET AND THROUGH ALL OF NORTH TEXAS BY THE TIME WE RING IN THE NEW YEAR. THIS FRONT WILL PROVIDE COOLER...BUT STILL DRY WEATHER...FOR A COUPLE OF DAYS. SOUTHERLY WINDS WILL RETURN LATE MONDAY NIGHT AND INCREASE SOME ON TUESDAY AHEAD OF THE NEXT SHORT WAVE AND COLD FRONT. THE INCREASING SOUTHERLY WINDS TUESDAY AND LOW RELATIVE HUMIDITIES WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS TUESDAY. THIS FRONT WILL THEN SWEEP THROUGH WEDNESDAY WITH NO PRECIPITATION EXPECTED ACROSS NORTH TEXAS. SOUTHERLY WINDS WILL RETURN BY LATE THURSDAY AND YET ANOTHER FRONT IS EXPECTED FRIDAY NIGHT/SATURDAY MORNING. AT THIS TIME IT LOOKS LIKE RAIN CHANCES WITH THE SYSTEM WILL LIKELY BE TO THE EAST OF THE FORECAST AREA. 58 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 73 38 60 34 56 / 5 0 0 0 0 WACO, TX 73 40 62 30 57 / 5 5 0 0 0 PARIS, TX 71 37 58 31 54 / 5 5 0 0 0 DENTON, TX 72 36 58 27 53 / 5 0 0 0 0 MCKINNEY, TX 72 37 60 30 55 / 5 0 0 0 0 DALLAS, TX 73 41 59 35 56 / 5 0 0 0 0 TERRELL, TX 71 40 59 32 57 / 5 5 0 0 0 CORSICANA, TX 72 40 62 33 57 / 5 5 0 0 0 TEMPLE, TX 73 37 61 30 57 / 5 5 0 0 0 MINERAL WELLS, TX 74 34 61 26 56 / 5 0 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1049 AM MST SAT DEC 31 2011 .AVIATION... STARTING TO SEE STRONGER WINDS COMING DOWN THE PALMER DIVIDE WITH A QUICK DIAL IN TO THE KCOS ASOS REVEALING A 50 KT GUST IN THE PAST FEW MINUTES. WIND DIRECTION HAS SHIFTED FROM A NORTHERLY COMPONENT AS SFC PRESSURE RISES ARE NOW STARTING TO DROP IN FROM THE NORTHWEST. RADAR SHOWS FINE LINE ON THE EDGE OF THESE STRONGER WINDS JUST TO THE NORTH OF KPUB AND SHOULD BE MOVING IN DURING BY 18Z. WILL CARRY GUST TO 50 KTS FOR KCOS AND KPUB FOR THE NEXT FEW HOURS. WINDS SHOULD EDGE DOWN SOME AFTER 21Z AND BECOME LIGHT AFTER 02-03Z. MODELS HAVE BEEN HANDLING KALS WINDS POORLY AND HAVE RELIED HEAVILY ON HIGH RES WRF MODEL AND SFC OBS. WINDS ALREADY GUSTING FROM THE WEST AT 32 KTS. COULD BRIEFLY SEE A GUST TO 40-45 KTS AS UPPER TROF AXIS PASSES. WILL BE MONITORING THIS TAF SITE CLOSELY FOR POSSIBLE UPDATES AS NEEDED. -KT && .PREV DISCUSSION... /ISSUED 953 AM MST SAT DEC 31 2011/ UPDATE... IMPRESSIVE 8+ MB 3 HR PRESSURE RISES SWINGING THROUGH NORTHWEST CO ATTM BEHIND UPPER TROF. WINDS HAVE BEEN GUSTING OVER 90 KTS AT KMYP...WITH SALIDA AND BUENA VISTA AIRPORTS SEEING GUSTS TO 55 KTS. UPPER TROF IN WV AND LATEST MODEL RUNS IS CERTAINLY MORE AMPLIFIED THAN RUNS FROM YESTERDAY...AND LATEST LOCAL 4KM WRF AND 12Z NAM12 SHOWING A WIDESPREAD SWATH OF 50-65 KT WINDS AT 800 MB SPREADING ACROSS THE SOUTHEAST PLAINS. STRONG DOWNWARD FORCING AND MIXING SHOULD BE SUFFICIENT TO TAP THESE WINDS ALOFT...RESULTING IN WIND GUST POTENTIAL OF 65 MPH ACROSS THE PLAINS...PERHAPS STRONGER IN SOME LOCATIONS. WINDS IN THE SAN LUIS VALLEY HAVE ALSO BEEN MUCH STRONGER THAN MODELS PREDICTED...AND MTN TOP WINDS ACROSS THE SAN JUANS AND LA GARITAS ARE EXPECTED TO INCREASE TO AROUND 70 KTS AT PEAK LEVEL SHORTLY. THUS...HAVE EXPANDED HIGH WIND WARNINGS TO INCLUDE THE REMAINDER OF THE SOUTHEAST PLAINS...AS WELL AS THE HIGHER AREAS OF THE EASTERN SAN JUANS AND LA GARITAS. ITS POSSIBLE THAT SOME OF THESE STRONG GUSTS MAY DESCEND INTO THE VALLEY EDGES AND NECESSITATE FURTHER EXPANSION OF THE WARNINGS. WILL CONTINUE TO MONITOR CLOSELY. -KT PREV DISCUSSION... /ISSUED 333 AM MST SAT DEC 31 2011/ SHORT TERM... (TODAY AND TONIGHT) .STRONG WINDS EXPECTED ACROSS THE CENTRAL AND EASTERN MOUNTAINS...NORTHERN I-25 CORRIDOR...AND NRN PORTIONS OF THE SOUTHEAST PLAINS TODAY... CURRENTLY...IR SATELLITE IMAGERY ALONG WITH H5 RUC ANALYSIS CLEARLY SHOWS THE APPROACHING SHORTWAVE CROSSING THE GREAT BASIN AND NORTHERN ROCKIES THIS AM...WITH THE TROF AXIS ROUGHLY OVER ID AND W MT AS OF 3 AM. SLC SFC OBS HAVE REPORTED HEFTY PRESSURE RISES...WHILE CLOSER TO HOME WINDS HAVE BEEN ON THE INCREASE ACROSS THE HIGHER ELEVATIONS. THE SENSOR ON PIKES PEAK REPORTED AN 84 MPH GUSTS AT 1 AM...SO STRONG WINDS ARE COMING AS THE PRESSURE GRADIENT TIGHTENS. TODAY...THE UPPER JET THAT IS CARVING OUT THE BASE OF THIS SHORTWAVE TROUGH HAS A CORE OF 100-110 KTS...AND IS EXPECTED TO SLIDE ACROSS THE STATE TODAY. STRONGW-SW WINDS THIS MORNING WILL QUICKLY SHIFT TO A NW DIRECTION AND STRENGTHEN THROUGH THE MORNING AS THE TROUGH MOVES EAST...WITH BOTH THE NAM AND GFS MODELS INDICATING THAT THE TROUGH AXIS WILL BE NEAR THE CO AND KS BORDER BY MIDDAY. MODEL CROSS SECTIONS SHOW A RAPID INTENSIFICATION OF WINDS AS THEY DROP TOWARDS THE SFC BETWEEN 12Z AND 18Z...AND GUSTS TO 60 MPH FOR THE LOWER ELEVATIONS ARE PROBABLE THIS MORNING. HOW WIDESPREAD THESE GUSTS WILL BE IS A QUESTION...BUT FEEL THAT MANY WILL EXPERIENCE HIGH WINDS TODAY. THEREFORE...THE HIGH WIND WARNING ALREADY IN PLACE FOR MUCH OF THE HIGHER TERRAIN...THE UPPER ARKANSAS RIVER VALLEY...MUCH OF THE I25 CORRIDOR AND FOR PORTIONS OF THE PLAINS ALONG HIGHWAY 50 AND NORTH LOOKS GOOD. THERE IS SOME CONCERN ON WHETHER OR NOT THE REST OF THE PLAINS NEED SOME SORT OF HIGHLIGHT...BUT GUT FEELING IS THAT THESE AREAS...THOUGH THEY WILL GET WINDY...WILL NOT REACH HIGH WIND CRITERIA IN A WIDE ENOUGH AREA. AS FOR TEMPS AND PCPN CHANCES...A RELATIVELY MILD NIGHT DUE TO THE INCREASING WINDS SHOULD GIVE A BOOST TO MAX TEMPS TODAY...AND TEMPS IN THE 50S WITH 40S FOR THE HIGH VALLEYS IS FORECAST. AS FOR PCPN...ONLY AREA THAT LOOKS LIKE IT WILL RECEIVE ANY SIGNIFICANT PCPN WILL BE THE CENT MTS AS THE W-NW FLOW ALOFT IS FAVORABLE FOR THAT AREA. LATEST MODELS CONTINUE TO PAINT AROUND ONE INCH OF SNOW POSSIBLE THROUGH THE DAY. FINALLY...AREAS OF BLOWING SNOW WILL BE A HAZARD OVER THE HIGHER MTN PASSES THIS MORNING AND TODAY. TONIGHT...AS THE UPPER DISTURBANCE PASSES TO THE EAST...THE SFC COLD FRONT DROPS DOWN THE E PLAINS SOME TIME AROUND 00Z. AS WINDS DIE DOWN...CLEARING SKIES AND COLD AIR FILTERING IN WILL SET THE STAGE FOR A COLD NIGHT WITH MIN TEMPS IN THE TEENS AND SINGLE DIGITS...AND BELOW ZERO FOR PORTIONS OF THE SLV. 27 LONG TERM... .JANUARY THAW... NOT MUCH SIGNIFICANT WEATHER IS ANTICIPATED DURING THIS PERIOD. A LARGE RIDGE OF HIGH PRESSURE ALOFT WILL BUILD OVER THE REGION STARTING MONDAY AND LAST THROUGH LATE WEEK. A WEAK DISTURBANCE WILL MOVE THROUGH THE RIDGE DURING THE TUESDAY TIME FRAME BUT THIS FEATURE IS RATHER WEAK AND NO SENSIBLE WX IS EXPECTED WITH IT. MAX TEMPERATURES FCSTED ATTM THROUGH MOST OF THE WEEK OVER THE PLAINS WILL BE 50S TO AROUND 60F...BUT THESE NUMBERS WILL LIKELY NEED TO BE ADJUSTED UPWARDS...ESPECIALLY ON THURSDAY AS 700 MB TEMPS ARE FCST TO BE IN THE +8 RANGE (WHICH WOULD EQUAL TEMPS AROUND 70F IF WE MIX DOWN DRY ADIABATICALLY). BY LATE IN THE WEEK A MORE AMPLIFIED PAC TROUGH IS FCST TO MOVE INTO THE REGION. ATTM THE BEST CHANCE OF PRECIP OVER THE AREA WOULD BE LATE FRIDAY INTO EARLY SATURDAY. TEMPS SHOULD COOL DOWN FOR NEXT WEEKEND. /34 AVIATION... VFR CONDITIONS FOR THE NEXT 24 HRS EXPECTED FOR KALS. FOR KCOS AND KPUB...THE MAIN CONCERN WILL BE STRONG W-NW WINDS DEVELOPING THIS MORNING AND LASTING THROUGH 22Z. WILL MAINTAIN MENTION OF WIND SHEAR FOR KCOS EARLY THIS MORNING THROUGH 14Z OR SO...BEFORE THE STRONGER WINDS ALOFT MAKE IT DOWN TO THE SFC. WIND SHEAR DOES NOT LOOK TO BE AN ISSUE FOR KPUB. GUSTS OF 45-50 KTS WILL BE POSSIBLE AT BOTH SITES...AND ALONG THE I25 CORRIDOR...THROUGH THE MORNING AND EARLY AFTERNOON. && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ058- 060>063-066-068-072>089-093>099. && $$ 31/77
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
953 AM MST SAT DEC 31 2011 .UPDATE... IMPRESSIVE 8+ MB 3 HR PRESSURE RISES SWINGING THROUGH NORTHWEST CO ATTM BEHIND UPPER TROF. WINDS HAVE BEEN GUSTING OVER 90 KTS AT KMYP...WITH SALIDA AND BUENA VISTA AIRPORTS SEEING GUSTS TO 55 KTS. UPPER TROF IN WV AND LATEST MODEL RUNS IS CERTAINLY MORE AMPLIFIED THAN RUNS FROM YESTERDAY...AND LATEST LOCAL 4KM WRF AND 12Z NAM12 SHOWING A WIDESPREAD SWATH OF 50-65 KT WINDS AT 800 MB SPREADING ACROSS THE SOUTHEAST PLAINS. STRONG DOWNWARD FORCING AND MIXING SHOULD BE SUFFICIENT TO TAP THESE WINDS ALOFT...RESULTING IN WIND GUST POTENTIAL OF 65 MPH ACROSS THE PLAINS...PERHAPS STRONGER IN SOME LOCATIONS. WINDS IN THE SAN LUIS VALLEY HAVE ALSO BEEN MUCH STRONGER THAN MODELS PREDICTED...AND MTN TOP WINDS ACROSS THE SAN JUANS AND LA GARITAS ARE EXPECTED TO INCREASE TO AROUND 70 KTS AT PEAK LEVEL SHORTLY. THUS...HAVE EXPANDED HIGH WIND WARNINGS TO INCLUDE THE REMAINDER OF THE SOUTHEAST PLAINS...AS WELL AS THE HIGHER AREAS OF THE EASTERN SAN JUANS AND LA GARITAS. ITS POSSIBLE THAT SOME OF THESE STRONG GUSTS MAY DESCEND INTO THE VALLEY EDGES AND NECESSITATE FURTHER EXPANSION OF THE WARNINGS. WILL CONTINUE TO MONITOR CLOSELY. -KT && .PREV DISCUSSION... /ISSUED 333 AM MST SAT DEC 31 2011/ SHORT TERM... (TODAY AND TONIGHT) ..STRONG WINDS EXPECTED ACROSS THE CENTRAL AND EASTERN MOUNTAINS...NORTHERN I-25 CORRIDOR...AND NRN PORTIONS OF THE SOUTHEAST PLAINS TODAY... CURRENTLY...IR SATELLITE IMAGERY ALONG WITH H5 RUC ANALYSIS CLEARLY SHOWS THE APPROACHING SHORTWAVE CROSSING THE GREAT BASIN AND NORTHERN ROCKIES THIS AM...WITH THE TROF AXIS ROUGHLY OVER ID AND W MT AS OF 3 AM. SLC SFC OBS HAVE REPORTED HEFTY PRESSURE RISES...WHILE CLOSER TO HOME WINDS HAVE BEEN ON THE INCREASE ACROSS THE HIGHER ELEVATIONS. THE SENSOR ON PIKES PEAK REPORTED AN 84 MPH GUSTS AT 1 AM...SO STRONG WINDS ARE COMING AS THE PRESSURE GRADIENT TIGHTENS. TODAY...THE UPPER JET THAT IS CARVING OUT THE BASE OF THIS SHORTWAVE TROUGH HAS A CORE OF 100-110 KTS...AND IS EXPECTED TO SLIDE ACROSS THE STATE TODAY. STRONGW-SW WINDS THIS MORNING WILL QUICKLY SHIFT TO A NW DIRECTION AND STRENGTHEN THROUGH THE MORNING AS THE TROUGH MOVES EAST...WITH BOTH THE NAM AND GFS MODELS INDICATING THAT THE TROUGH AXIS WILL BE NEAR THE CO AND KS BORDER BY MIDDAY. MODEL CROSS SECTIONS SHOW A RAPID INTENSIFICATION OF WINDS AS THEY DROP TOWARDS THE SFC BETWEEN 12Z AND 18Z...AND GUSTS TO 60 MPH FOR THE LOWER ELEVATIONS ARE PROBABLE THIS MORNING. HOW WIDESPREAD THESE GUSTS WILL BE IS A QUESTION...BUT FEEL THAT MANY WILL EXPERIENCE HIGH WINDS TODAY. THEREFORE...THE HIGH WIND WARNING ALREADY IN PLACE FOR MUCH OF THE HIGHER TERRAIN...THE UPPER ARKANSAS RIVER VALLEY...MUCH OF THE I25 CORRIDOR AND FOR PORTIONS OF THE PLAINS ALONG HIGHWAY 50 AND NORTH LOOKS GOOD. THERE IS SOME CONCERN ON WHETHER OR NOT THE REST OF THE PLAINS NEED SOME SORT OF HIGHLIGHT...BUT GUT FEELING IS THAT THESE AREAS...THOUGH THEY WILL GET WINDY...WILL NOT REACH HIGH WIND CRITERIA IN A WIDE ENOUGH AREA. AS FOR TEMPS AND PCPN CHANCES...A RELATIVELY MILD NIGHT DUE TO THE INCREASING WINDS SHOULD GIVE A BOOST TO MAX TEMPS TODAY...AND TEMPS IN THE 50S WITH 40S FOR THE HIGH VALLEYS IS FORECAST. AS FOR PCPN...ONLY AREA THAT LOOKS LIKE IT WILL RECEIVE ANY SIGNIFICANT PCPN WILL BE THE CENT MTS AS THE W-NW FLOW ALOFT IS FAVORABLE FOR THAT AREA. LATEST MODELS CONTINUE TO PAINT AROUND ONE INCH OF SNOW POSSIBLE THROUGH THE DAY. FINALLY...AREAS OF BLOWING SNOW WILL BE A HAZARD OVER THE HIGHER MTN PASSES THIS MORNING AND TODAY. TONIGHT...AS THE UPPER DISTURBANCE PASSES TO THE EAST...THE SFC COLD FRONT DROPS DOWN THE E PLAINS SOME TIME AROUND 00Z. AS WINDS DIE DOWN...CLEARING SKIES AND COLD AIR FILTERING IN WILL SET THE STAGE FOR A COLD NIGHT WITH MIN TEMPS IN THE TEENS AND SINGLE DIGITS...AND BELOW ZERO FOR PORTIONS OF THE SLV. 27 LONG TERM... ..JANUARY THAW... NOT MUCH SIGNIFICANT WEATHER IS ANTICIPATED DURING THIS PERIOD. A LARGE RIDGE OF HIGH PRESSURE ALOFT WILL BUILD OVER THE REGION STARTING MONDAY AND LAST THROUGH LATE WEEK. A WEAK DISTURBANCE WILL MOVE THROUGH THE RIDGE DURING THE TUESDAY TIME FRAME BUT THIS FEATURE IS RATHER WEAK AND NO SENSIBLE WX IS EXPECTED WITH IT. MAX TEMPERATURES FCSTED ATTM THROUGH MOST OF THE WEEK OVER THE PLAINS WILL BE 50S TO AROUND 60F...BUT THESE NUMBERS WILL LIKELY NEED TO BE ADJUSTED UPWARDS...ESPECIALLY ON THURSDAY AS 700 MB TEMPS ARE FCST TO BE IN THE +8 RANGE (WHICH WOULD EQUAL TEMPS AROUND 70F IF WE MIX DOWN DRY ADIABATICALLY). BY LATE IN THE WEEK A MORE AMPLIFIED PAC TROUGH IS FCST TO MOVE INTO THE REGION. ATTM THE BEST CHANCE OF PRECIP OVER THE AREA WOULD BE LATE FRIDAY INTO EARLY SATURDAY. TEMPS SHOULD COOL DOWN FOR NEXT WEEKEND. /34 AVIATION... VFR CONDITIONS FOR THE NEXT 24 HRS EXPECTED FOR KALS. FOR KCOS AND KPUB...THE MAIN CONCERN WILL BE STRONG W-NW WINDS DEVELOPING THIS MORNING AND LASTING THROUGH 22Z. WILL MAINTAIN MENTION OF WIND SHEAR FOR KCOS EARLY THIS MORNING THROUGH 14Z OR SO...BEFORE THE STRONGER WINDS ALOFT MAKE IT DOWN TO THE SFC. WIND SHEAR DOES NOT LOOK TO BE AN ISSUE FOR KPUB. GUSTS OF 45-50 KTS WILL BE POSSIBLE AT BOTH SITES...AND ALONG THE I25 CORRIDOR...THROUGH THE MORNING AND EARLY AFTERNOON. && .PUB WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ058- 060>063-066-068-072>089-093>099. && $$ 31/77
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
355 PM EST Sat Dec 31 2011 .SYNOPSIS... 20Z water vapor and H4 RUC analysis shows an amplified but progressive northern stream flow pattern across North America. Pattern currently consists of troughs over the Northeastern states and also digging through the northern Plains/Upper MS valley. Between these features we find ridging over the Great Lakes region, and also building over the Pacific Northwest. The flow pattern across the southern tier of the CONUS/northern Gulf coast takes on a more zonal configuration. Pleasant afternoon ongoing across the forecast area after the dense morning fog. At the surface, a weak front is analyzed just to the north of the I-10 corridor and is essentially washing out this afternoon/evening. South of this front a ridge of high pressure extends across the FL peninsula and into the NE Gulf of Mexico. Temperatures are quite enjoyable out there for the last day of December, with many locations reaching the lower to middle 70s. Temperatures along the immediate coast are being held in the 60s with light onshore flow off the relatively cooler shelf waters. && .SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)... Tonight, Main concern will be dealing with the potential for areas of dense fog development later this evening and into the early morning hours of Sunday. Setup for fog seems quite good with subtle moisture advection from the south underneath abundant dry air above the surface. High-resolution and statistic guidance are in fair agreement in the fog development commencing later this evening along and south of the I-10 corridor, and then expanding quickly northward. Evening/overnight shifts will need to monitor the situation in case dense fog advisories become necessary for portions of the area. Outside of the development fog, the forecast will be dry and quiet for any outdoor first night festivities. Temperatures will generally bottom out in the lower to middle 50s. Sunday, Overall upper level pattern will further amplify as the trough over the mid-section of the county moves east and begins to phase with additional shortwave energy from the north. A weak cold front ahead of this feature will move into our western zones by early afternoon and then pass east of our area Sunday evening. Expecting Sunday to start out with areas/widespread fog across the eastern zones. Due to the weak sun angle, the fog will likely linger through much of the morning. Forecast is a bit trickier further west toward Panama City and Dothan in closer proximity to the approaching front. Will clear the dense fog out of these western zones a few hours earlier as a gradient tightens and promotes more efficient mixing during the morning hours. Will keep PoPs around 10% with this frontal passage as the overall column moisture and synoptic forcing is not impressive. Will add sct sprinkles to the grids as most guidance members are showing some light QPF. Doubt most areas will see measurable precip, but a few raindrops can not be ruled out. Sunday night, A drier and noticeably cooler airmass (although not unusual) will filter in during the night behind Sunday`s front. Skies will be clearing with a steady NW breeze. Still not expecting any freezing temperatures as low temps will range from the middle 30s north of Dothan and Albany to the lower 40s south and east of Tallahassee and Valdosta. Monday/Monday night, A significant amplification to the upper level pattern will occur during the daylight hours with an impressive trough across the eastern third of the nation by the end of the day. This amplification will be accompanied by a strong surge of arctic air into the eastern states. This stronger more arctic configuration front is not scheduled to arrive until Monday evening. Therefore, much of our area will reside within the thermal ridge ahead of the front Monday afternoon, with temperatures climbing into the middle and upper 50s. The big change will occur Monday evening as the arctic front quickly passes through. As of the 12Z guidance cycle, the ECMWF/Canadian and UKMET all show 850mb temps down between -8 and -10C around KTLH and -12C up toward Albany and Tifton by sunrise. The GFS remains an outlier on the warm side, with 850mb temps over the CWA up to 10C warmer than the other global guidance members. Going to side with the colder guidance consensus, which is also in agreement with HPC. The resulting forecast will show a widespread advection freeze Monday night. A steady northwest wind will add to the cold with windchill values down into the upper teens by sunrise. && .LONG TERM (TUESDAY MORNING THROUGH NEXT SATURDAY)... The main surge of arctic air will advect into our forecast area by early Tuesday. While all of the numerical guidance shows a deep long wave 500 mb trough over the eastern U.S. and a strong arctic surface high diving southward into the Southern Plains, the solutions differ as to just how cold it will be here. The NAM, ECMWF, and CMC are very cold with an 850 mb temperature around -9 deg C at Tallahassee early Tuesday. The outlier GFS is a good 10 deg C warmer than this. The GFS may be correct, but it seems prudent at this point to average the colder solutions into our forecast so that we don`t miss too badly if the GFS is too warm. Despite the winds remaining in the 5-10 MPH range most of Monday night, lows will likely fall well below freezing over our entire forecast area (even at the beaches). We may meet our local wind chill advisory criteria for the first time this season. Even if the warmer GFS verifies, GFS BUFKIT soundings indicate highs will struggle to reach the mid 40s, which is several degrees colder than the GFS MOS. All the global NWP guidance continues to forecast the arctic surface high to become centered over Tallahassee Wednesday morning. This will allow the winds to become calm overnight. With calm winds, dewpoints around 10 degrees, and one of the longest nights of the year, we think low temperatures will plummet more than what the GFS MOS is currently forecasting (mid 20s). Near-record lows in the upper teens seem more likely given such a favorable cooling setup, with mid to upper 20s at the coast and in the larger cities. We looked back at two of the coldest recent arctic outbreaks here (that occurred without snow) and found some similarities to this forecast. The two that we examined where the January 1985 and December 1983 outbreaks, both of which set records locally. Early indications are that this upcoming outbreak will not be quite as bad given that the surface high may be slightly weaker, and the 850 mb cold pool is not expected to be quite as expansive as was observed in the previous cases. However, we will continue to monitor subsequent model trends as these short-lived arctic outbreaks can produce surprisingly cold temperatures in the Deep South, even when the winds are not calm. A slow warming trend will begin Wednesday afternoon, though the GFS MOS appears to be bouncing back toward climatology too quickly, and we plan to slow this warming down a bit. In fact, the surface high will still be in a favorable position for another freeze Thursday morning, but a weak upper level trough passing by may bring enough upper level moisture to counteract the boundary layer cooling. The 00 UTC GFS and ECMWF forecast a weak cold front west-northwest of our forecast area by Saturday. The GFS solution is more progressive while the ECMWF appears to stall the front too far away for any rain for our area. Given how far out this and the recent inconsistencies in the GFS for this time frame, we will leave out any mention of PoP above 10 percent. Milder temperatures will return Friday and Saturday. && .AVIATION (Through 18Z UTC Sunday)... Dense fog is expected to blanket the area tomorrow morning with visibilities down to 1/4 SM. A weak cold front will begin to approach Southeast Alabama and the western Florida Panhandle on Sunday helping to mix out the fog by mid morning at KDHN and KECP. Timing is everything so we feel lowered CIGS and VSBYs will drag into late morning at KABY, KTLH and KVLD. && .MARINE... A surface ridge of high pressure over the northeast Gulf of Mexico will keep winds and seas low through tonight. A cold front will then cross the forecast waters Sunday and Sunday evening. Winds will shift northerly in the wake of this front and quickly increase to advisory levels. A secondary cold front will then cross the forecast waters Monday evening helping to keep winds and seas elevated to advisory levels. The current forecast will reflect a pattern more in line with the ECMWF/Canadian/UKMET consensus solutions. These guidance members bring a stronger push of cold air advection compared to the outlier GFS solution. Therefore, wind gusts are forecast to approach gale force at times Monday night, especially over the offshore legs. Winds and seas will then quickly decrease Tuesday night into Wednesday as another ridge of high pressure builds over the region. && .FIRE WEATHER... Red Flag conditions are unlikely through Sunday. However, very dry air will increase the threat for Red Flag conditions on Monday and Tuesday as cold, very dry air moves into the region on gusty northwest winds. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 50 75 40 57 25 / 0 10 10 0 0 Panama City 58 74 42 56 29 / 0 10 0 0 0 Dothan 53 72 37 54 25 / 10 10 0 0 0 Albany 49 72 36 53 25 / 10 10 0 0 0 Valdosta 48 74 39 54 25 / 0 10 10 0 0 Cross City 47 74 43 58 26 / 0 0 10 0 0 Apalachicola 56 71 41 57 29 / 0 10 10 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... AL...None. GA...None. FL...None. GM...None. && $$ SYNOPSIS/SHORT TERM/MARINE...MROCZKA LONG TERM...FOURNIER AVIATION/FIRE WEATHER...LANIER
AREA FORECAST DISCUSSION
NWS LINCOLN IL
158 PM CST SAT DEC 31 2011 .DISCUSSION... ISSUED 158 PM CST SAT DEC 31 2011 GUSTY/MILD WINDS ARE DEVELOPING ACROSS CENTRAL AND SOUTHEAST ILLINOIS THIS AFTERNOON AHEAD OF A STRENGTHENING STORM SYSTEM IN THE PLAINS. WINDS WILL SWING AROUND TO THE WEST BY LATE TONIGHT AS A STRONG COLD FRONT PUSHES THROUGH THE AREA. THESE WINDS WILL TRANSPORT MUCH COLDER AIR INTO THE AREA FOR THE BEGINNING OF THE WEEK...WITH GUSTS AROUND 45 MPH LIKELY FROM FRONTAL PASSAGE INTO SUNDAY EVENING. MAIN FORECAST CONCERNS TODAY REVOLVE AROUND HOW STRONG THE WINDS WILL BE ON EITHER SIDE OF THE FRONT FOR THE NEXT 24 HOURS...AS WELL AS PRECIPITATION CHANCES WITH FRONTAL PASSAGE. 12Z MODELS CONTINUE TO BE IN GOOD OVERALL AGREEMENT FOR THE NEXT SEVERAL DAYS. AFTER THE WINDS DIE DOWN BY LATER MONDAY...THE BALANCE OF THE FORECAST PERIOD SHOULD FEATURE BENIGN WEATHER. SHORT TERM...TONIGHT THROUGH TUESDAY...A DEEPENING AREA OF LOW PRESSURE WILL TRACK FROM THE NEBRASKA/IOWA BORDER AREA THIS AFTERNOON INTO NORTHEAST ONTARIO SUNDAY EVENING. AS THIS LOW PASSES TO THE NORTH OF THE FORECAST AREA OVERNIGHT...IT WILL DRAG A STRONG COLD FRONT THROUGH THE AREA. WINDS ARE EXPECTED TO BECOME QUITE STRONG OUT OF THE WEST NORTHWEST IN THE WAKE OF THE FRONT...WITH GUSTS OF AT LEAST 45 MPH COMMON FROM FROPA INTO SUNDAY EVENING. WIND GUSTS MAY BE EVEN STRONGER IN NORTHERN SECTIONS OF THE FORECAST AREA LATE TONIGHT THROUGH MIDDAY SUNDAY AS FORECAST SOUNDINGS SUGGEST EVEN MORE IMPRESSIVE DOWNWARD MOMENTUM TRANSFER IN THIS AREA...AND THIS AREA IS CLOSER TO THE STRONG 8 MB/3 HOUR SURFACE PRESSURE FALL/RISE COUPLET THAT APPEARS LIKELY TO TRACK ALONG THE I-80 CORRIDOR. HAVE POSTED A WIND ADVISORY FROM MIDNIGHT TONIGHT INTO MIDNIGHT SUNDAY TO HIGHLIGHT THE STRONG WIND POTENTIAL. CAN NOT RULE OUT THE POTENTIAL FOR A FEW COUNTIES NEEDING TO BE UPGRADED TO A HIGH WIND WARNING...BUT THIS POTENTIAL IS HIGHER NORTH/WEST OF CENTRAL ILLINOIS. THERE IS ONLY A LIMITED RISK OF PRECIPITATION WITH THE PASSAGE OF THIS STORM SYSTEM. THE BULK OF THE FORECAST AREA WILL HAVE TOO SHALLOW OF A MOISTURE DEPTH TO SUPPORT PRECIPITATION DEVELOPMENT. HOWEVER...LOCATIONS ROUGHLY ALONG AND NORTH OF A RUSHVILLE TO BLOOMINGTON LINE STAND THE BEST CHANCE TO GET BRUSHED BY THE WRAP AROUND CLOUD/PRECIP SHIELD TONIGHT AS THE LOW PASSES BY. THIS RISK SHOULD END BY SUNRISE...AND ANY PRECIPITATION THAT DOES FALL IS EXPECTED TO BE MINIMAL. WHILE WINDS WILL FALL BELOW ADVISORY CRITERIA SUNDAY EVENING...A STRONG PRESSURE GRADIENT SUPPORTS WINDS STAYING ON THE GUSTY SIDE THROUGH MONDAY. THE PERIOD OF MONDAY THROUGH TUESDAY ALSO STANDS TO BE THE COLDEST OF THE WINTER SEASON THUS FAR...THOUGH TEMPERATURES WILL STILL ONLY BE A FEW DEGREES COLDER THAN NORMAL. LONG TERM...WEDNESDAY THROUGH SATURDAY...A CLIPPER SYSTEM IS PROGGED TO PASS TO OUR NORTH ON WEDNESDAY AND IS NOT EXPECTED TO BE A PRECIPITATION RISK LOCALLY. THEN...WITH SURFACE RIDGING PUSHING OFF TO THE EAST AND UPPER RIDGING BUILDING OVERHEAD FOR THE REST OF THE PERIOD...QUIET WEATHER AND A RETURN TO UNSEASONABLY MILD CONDITIONS IS ANTICIPATED. BAK && .AVIATION... ISSUED 1125 AM CST SAT DEC 31 2011 MVFR STRATUS DECK STILL LINGERING OVER THE NORTHEAST HALF OF ILLINOIS...WITH SOME DIURNAL REDEVELOPMENT ON THE WESTERN FLANK FROM KGBG-KTMO. WILL LIKELY SEE THIS BREAK UP BY ABOUT 21Z AT KPIA/KDEC/KBMI...BUT AM NOT TERRIBLY OPTIMISTIC FURTHER EAST AFTER LOOKING AT RUC FORECAST SOUNDINGS. MAIN PROBLEM MUCH OF THE PERIOD WILL BE WITH THE WINDS. SOUTHERLY WINDS TO CRANK UP THIS EVENING AHEAD OF A RAPIDLY INTENSIFYING LOW ACROSS IOWA. WILL BEGIN SEEING THE WINDS SWITCHING WESTERLY BETWEEN 06-12Z AS THE LOW PASSES TO OUR NORTH. VERY STRONG PRESSURE RISES BEHIND THE LOW WILL RESULT IN 35-40 KNOT GUSTS IN MANY AREAS THROUGH ABOUT MID AFTERNOON...WITH SOME POTENTIAL FOR HIGHER THAN 45 KNOTS BASED ON LOW LEVEL SOUNDING DATA. ANOTHER SURGE OF MVFR CEILINGS IS EXPECTED AFTER 06Z AS THE LOW GOES BY. WESTERN TAF SITES WILL PROBABLY SEE CEILINGS SCATTER OUT BY ABOUT 14-15Z...BUT AREAS NEAR KCMI WILL LIKELY REMAIN IN MVFR CONDITIONS UNTIL CLOSER TO MIDDAY. GEELHART && .ILX WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR ILZ027>031-036>038-040>057-061>063-066>068-071>073. && $$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1125 AM CST SAT DEC 31 2011 .DISCUSSION... ISSUED 1005 AM CST SAT DEC 31 2011 BACK EDGE OF THE STRATUS DECK EXTENDING FROM ABOUT MOLINE...TO DECATUR...TO OLNEY. AWIPS TIME-OF-ARRIVAL TOOL INDICATING THE CLEARING SHOULD REACH CHAMPAIGN AROUND 11 AM AND BY OUT OF THE CWA BY ABOUT 1230 PM. STILL EXPECTING TO SEE THE WINDS PICK UP THIS AFTERNOON AS 30-35 KNOT WINDS AT 925 MB START MIXING TOWARD THE SURFACE. HAVE SENT SOME UPDATED ZONES/GRIDS TO REFLECT THE LATEST CLEARING TRENDS. WINDS AND TEMPERATURES LOOKED FAIRLY GOOD SO LITTLE CHANGE WAS MADE THERE. WATER VAPOR IMAGERY SHOWING UPPER TROUGH DIGGING ACROSS WYOMING AND COLORADO LATE THIS MORNING. THIS WILL SOON BE INTERACTING WITH A COLD FRONT EXTENDING FROM SOUTH DAKOTA TO WESTERN KANSAS...AND RAPIDLY INTENSIFY A SURFACE LOW CURRENTLY OVER NEBRASKA. EARLY LOOK AT 12Z MODELS REMAIN QUITE IMPRESSIVE WITH THIS SYSTEM...WITH 3 HOUR PRESSURE RISES ON THE ORDER OF 7 TO 9 MB EXPECTED FROM LATE TONIGHT THROUGH MIDDAY SUNDAY BEHIND THE LOW. HIGH-RESOLUTION LOCAL MODELS SHOWING STRONG WINDS MOVING INTO THE WESTERN CWA BETWEEN 2 AND 6 AM...AND ACROSS THE REMAINDER OF THE CWA EARLY SUNDAY MORNING...WITH THE CHICAGO WRF AND NAM-DNG MODELS SHOWING SOME POTENTIAL IN EXCESS OF 50 MPH. WIND HEADLINES WILL BE FORTHCOMING IN THE NEXT FEW HOURS...BUT WILL BE COORDINATING WITH NEIGHBORING AREAS TO DETERMINE ADVISORY VS WARNING POTENTIAL. GEELHART && .AVIATION... ISSUED 1125 AM CST SAT DEC 31 2011 MVFR STRATUS DECK STILL LINGERING OVER THE NORTHEAST HALF OF ILLINOIS...WITH SOME DIURNAL REDEVELOPMENT ON THE WESTERN FLANK FROM KGBG-KTMO. WILL LIKELY SEE THIS BREAK UP BY ABOUT 21Z AT KPIA/KDEC/KBMI...BUT AM NOT TERRIBLY OPTIMISTIC FURTHER EAST AFTER LOOKING AT RUC FORECAST SOUNDINGS. MAIN PROBLEM MUCH OF THE PERIOD WILL BE WITH THE WINDS. SOUTHERLY WINDS TO CRANK UP THIS EVENING AHEAD OF A RAPIDLY INTENSIFYING LOW ACROSS IOWA. WILL BEGIN SEEING THE WINDS SWITCHING WESTERLY BETWEEN 06-12Z AS THE LOW PASSES TO OUR NORTH. VERY STRONG PRESSURE RISES BEHIND THE LOW WILL RESULT IN 35-40 KNOT GUSTS IN MANY AREAS THROUGH ABOUT MID AFTERNOON...WITH SOME POTENTIAL FOR HIGHER THAN 45 KNOTS BASED ON LOW LEVEL SOUNDING DATA. ANOTHER SURGE OF MVFR CEILINGS IS EXPECTED AFTER 06Z AS THE LOW GOES BY. WESTERN TAF SITES WILL PROBABLY SEE CEILINGS SCATTER OUT BY ABOUT 14-15Z...BUT AREAS NEAR KCMI WILL LIKELY REMAIN IN MVFR CONDITIONS UNTIL CLOSER TO MIDDAY. GEELHART && .PREV DISCUSSION... ISSUED 246 AM CST SAT DEC 31 2011 ONE MORE MILD DAY EXPECTED...BEFORE WINDY AND SHARPLY COLDER CONDITIONS ARRIVE EARLY NEXT WEEK. SHORT TERM...TODAY THROUGH SUNDAY 08Z SATELLITE IMAGERY SHOWS OVERCAST CONDITIONS ACROSS CENTRAL ILLINOIS...WITH CLOUD COVER PERSISTING WELL UPSTREAM INTO IOWA AND MINNESOTA AS WELL. LARGE BREAK IN THE CLOUDS OVER WISCONSIN AND NORTHERN ILLINOIS WILL GENERALLY WORK ITS WAY E/SE THROUGH THE CHICAGO AREA INTO NORTHWEST INDIANA...WHILE PREVAILING NORTHWESTERLY LOW-LEVEL FLOW WILL KEEP CLOUD COVER IN PLACE ACROSS CENTRAL ILLINOIS THROUGH MID-MORNING. NAM 925MB RH FIELD SHOWS MOISTURE GRADUALLY DISSIPATING TOWARD MIDDAY...RESULTING IN CLEARING SKIES. MOSTLY SUNNY AND UNSEASONABLY WARM CONDITIONS WILL PREVAIL THIS AFTERNOON...AS BRISK SOUTHERLY WINDS DEVELOP IN ADVANCE OF THE NEXT APPROACHING SYSTEM. TIGHTENING PRESSURE GRADIENT AND FORECAST SOUNDINGS SUGGEST WIND GUSTS UP TO 30 MPH ACROSS THE WESTERN HALF OF THE KILX CWA. THANKS TO THE AMPLE SUNSHINE AND STEADY SOUTHERLY FLOW...HIGH TEMPERATURES WILL TOP THE 50 DEGREE MARK IN MOST LOCATIONS. AMPLIFYING SHORT-WAVE WILL PUSH A STRONG COLD FRONT THROUGH CENTRAL ILLINOIS TONIGHT...ACCOMPANIED BY CLOUDS AND PERHAPS A FEW SCATTERED SHOWERS. DUE TO LIMITED MOISTURE RETURN FROM THE GULF...WILL ONLY CARRY SLIGHT CHANCE POPS WITH FROPA...MAINLY ACROSS THE NORTHERN CWA IN CLOSER PROXIMITY TO STRONGEST UPPER DYNAMICS. ONCE THE FRONT PASSES...VERY WINDY CONDITIONS WILL DEVELOP ON SUNDAY AS STRONG COLD ADVECTION COMES IN. TIGHT PRESSURE GRADIENT AND SCREAMING LOW-LEVEL WINDS...SUGGEST GUSTS COULD REACH 40 MPH OR GREATER AT TIMES. HIGH TEMPS WILL STRUGGLE TO RISE MUCH FROM EARLY MORNING LOWS...WITH READINGS ONLY REACHING THE UPPER 30S AND LOWER 40S. LONG TERM...MONDAY THROUGH FRIDAY A BRIEF SHOT OF COLD AIR WILL INVADE THE MIDWEST EARLY NEXT WEEK...AS DEEP UPPER TROUGH DIGS ACROSS THE EASTERN CONUS. ECMWF AND GFS ARE NOW QUITE SIMILAR WITH THEIR THERMAL PROFILES...WITH BOTH MODELS INDICATING HIGH TEMPS ONLY IN THE UPPER 20S AND LOWER 30S FOR BOTH MONDAY AND TUESDAY. COLDEST MORNING OF THE FORECAST PERIOD WILL BE TUESDAY MORNING...WHEN HIGH PRESSURE RIDGE BUILDING IN FROM THE WEST WILL ALLOW LOW TEMPS TO BOTTOM OUT IN THE TEENS. AFTER THAT...BOTH MODELS CONTINUE TO ADVERTISE A QUICK RETURN TO ABOVE NORMAL TEMPS BY THE END OF THE WEEK AS THE TROUGH DEPARTS AND W/SW FLOW RETURNS. HAVE BOOSTED HIGH TEMPS BACK INTO THE 40S BY THURSDAY...WITH EVEN WARMER READINGS IN THE 50S BY FRIDAY. BARNES && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
222 PM CST SAT DEC 31 2011 .SYNOPSIS... 300 HPA 12Z MAP ANALYSIS SHOWS A STRONG 140-145 KT JET EXTENDING ACROSS THE PACIFIC NORTHWEST AND EASTWARDS ACROSS THE GREAT BASIN. AT 500 HPA, STRONG COLD AIR ADVECTION WITH TEMPERATURES CHANGES IN THE 5 TO 10 DEGREE C RANGE WERE NOTED IN COMPARING THE 00Z TO 12Z MAPS ACROSS THE ROCKIES. THE COLDEST AIR AT 500 HPA - AROUND -35 DEG C - EXTENDED FROM BRITISH COLUMBIA SOUTH INTO MONTANA. SIMILAR CHANGES IN TEMPERATURES WERE ALSO NOTED AT 700 AND 750 HPA WELL UPSTREAM OF KANSAS. ACROSS THE PLAINS, A WARM AND DRY PLUME PREVAILED AT 700/850 HPA. AT THE SURFACE, A COLD FRONT WAS PUSHING ACROSS THE HIGH PLAINS WITH VERY STRONG WINDS (SEVERE, IN FACT) WERE NOTED IN THE WAKE OF THE BOUNDARY. -SUGDEN && .DISCUSSION... DAYS 1-2... NEW YEARS EVE: SHORT TERM CONCERN IS WINDS. SEVERAL REPORTS OF 58+ MPH WINDS WERE NOTED ACROSS NE COLORADO/NW KANSAS EARLY THIS AFTERNOON. HRRR GUIDANCE STILL SUPPORTS WINDS (EITHER SUSTAINED OR GUSTS) MEETING WARNING CRITERIA LATE THIS AFTERNOON AND INTO THE EARLY EVENING. WINDS SHOULD DECREASE SIGNIFICANTLY IN THE 8-9 PM CST TIME RANGE. SECOND CONCERN WAS PRECIPITATION. HAVE 15 POPS IN THE GRIDS AS COLD POOL MOVES ACROSS NORTH CENTRAL KANSAS AND THERE COULD BE ENOUGH INSTABILITY FOR A FEW SHOWERS. HRRR FORECAST COMPOSITE RADAR IMAGERY AS ALSO SUGGESTING AS SUCH. WITH THE EXCEPTION OF CLOUDS ACROSS THE INTERSTATE 70 CORRIDOR, RELATIVELY CLEAR SKY CONDITIONS ARE EXPECTED. TEMPERATURES OF UPPER TEENS DEG F WEST TO AROUND 30 DEG F EAST ARE EXPECTED THROUGH THE OVERNIGHT HOURS. NEW YEARS DAY: COOLER TEMPERATURES BUT SEASONABLE OVERALL WILL RING IN NEW YEAR TOMORROW. WITH THE AFOREMENTIONED STRONG COLD AIR ADVECTION, 850 HPA TEMPERATURES WILL DECREASE TO THE -1 TO -2 DEG C RANGE. THIS SUPPORTS LOW 40S DEG F ACROSS MUCH OF WEST CENTRAL AND SOUTHWEST KANSAS. THE EXCEPTION IS TOWARDS SOUTH CENTRAL KANSAS WHERE A LARGER MIXING LAYER WILL SUPPORT SURFACE TEMPERATURES IN THE UPPER 40S TO AROUND 50 DEG F. WITH DRY NORTHWEST FLOW ALOFT PREVAILING IN THE WAKE OF A DEPARTING TROUGH, POPS WILL REMAIN AT ZERO THROUGH THE FIRST DAY OF 2012. SUNDAY EVENING: STRONG HIGH PRESSURE OF AROUND 1040 HPA WILL SLIDE ACROSS THE PLAINS OVERNIGHT SUNDAY. THIS WILL ALLOW FOR LIGHT WINDS. FORECAST SOUNDINGS SHOW A FAIRLY DRY PROFILE, SO THINK A GOOD RADIATIONAL COOLING NIGHT WILL OCCUR. LOW TEENS DEG F IS EXPECTED ACROSS THE NORTHWEST COUNTIES TOWARDS SCOTT CITY WITH AROUND 20 DEG F EXPECTED TOWARDS MEDICINE LODGE. AGAIN, NOT EXPECTING ANY PRECIPITATION WITH INCREASING 500 HPA ALOFT AND HIGH PRESSURE AT THE SURFACE. MONDAY: 500 HPA HEIGHTS OF AROUND 575-580 DM ARE EXPECTED MONDAY. SFC WINDS WILL TURN MORE SOUTHERLY MONDAY AFTERNOON ON THE WESTERN SIDE OF THE DEPARTING SURFACE HIGH. TEMPERATURES WILL REMAIN SEASONABLE MONDAY WITH HIGHS IN THE 40S DEG F FOR MUCH OF SOUTHWEST KANSAS. WILL KEEP POPS AT ZERO MONDAY WITH HIGH PRESSURE ALOFT/SUBSIDENCE OCCURRING ACROSS WESTERN KANSAS. -SUGDEN DAYS 3-7... MUCH OF THE SENSIBLE WEATHER ACROSS SOUTHWEST KANSAS IN THE MEDIUM RANGE WILL BE INFLUENCE BY SUBSTANTIAL RIDGING AS AN ANOMALOUS 585 DAM H5 HIGH BUILDS ACROSS THE SOUTHWEST. THIS WILL LEAD TO A FAIRLY SIGNIFICANT WARMING OF THE LOWER TROPOSPHERE YIELDING HIGHS IN THE 50S TO LOWER 60S WEDNESDAY AND THURSDAY. BY THE END OF THE WEEK...THE GLOBAL MODELS SUGGEST AN EROSION OF THE RIDGE WITH LOWERING HEIGHTS ACROSS THE NORTHWESTERN CONUS. THE DETAILS OF THE PATTERN CHANGE ARE STILL RATHER UNCLEAR...BUT AS WE HEAD INTO THE DAY 7 PORTION OF THIS FORECAST...THERE ARE SOME SIGNALS IN THE GLOBAL MODELS (PARTICULARLY THE ECMWF) OF STORM DEVELOPMENT OVER THE ROCKIES/PLAINS. FOR THIS UPDATE CYCLE...A DRY FORECAST IS IN THE CARDS THROUGH SATURDAY. -UMSCHEID && .AVIATION... FOR THE 18Z TAF ISSUANCE...HIGH WIND EVENT WILL AFFECT GCK, DDC, HYS THIS AFTERNOON THROUGH THIS EVENING. THE THINKING IS THAT THE PEAK OF THE HIGH WIND EVENT WILL BE FROM ROUGHLY 21Z TO 00Z WHEN FREQUENT GUSTS OF 45 TO 50 KNOTS CAN BE EXPECTED FROM THE NORTHWEST. A FEW SCATTERED SHOWERS WILL LIKELY DEVELOP BEHIND THE LOW AFFECTING THE HYS TERMINAL AND AS SUCH HAVE INSERTED VCSH EARLY THIS EVENING FOR A FEW HOURS. THERE IS NOT EXPECTED TO BE A REDUCTION IN VISIBILITY/CEILING INTO THE VFR CATEGORY...BUT SOME STRATUS WITH A 2000 TO 3000 FOOT CEILING IS EXPECTED AT HYS AND PERHAPS DDC FOR A FEW HOURS. LATE TONIGHT WINDS WILL DECREASE TO BELOW 15 KNOTS REMAINING OUT OF THE NORTHWEST. -UMSCHEID && .PRELIMINARY POINT TEMPS/POPS... DDC 22 43 18 45 / 0 0 0 0 GCK 22 40 16 44 / 0 0 0 0 EHA 19 42 19 46 / 0 0 0 0 LBL 20 42 18 46 / 0 0 0 0 HYS 25 43 16 42 / 20 0 0 0 P28 28 49 21 45 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 9 PM CST /8 PM MST/ THIS EVENING FOR KSZ030-031-043>046-061>066-074>081-084>090. && $$ FN36/25/25
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1137 AM CST SAT DEC 31 2011 ...UPDATE TO AVIATION... .UPDATE... HAVE UPDATED THE FORECAST THROUGH MIDNIGHT IN AN ATTEMPT TO NAIL DOWN THE EXPECTED WIND GUSTS AND RH VALUES...ADJUST THE WIND ADVISORY ACCORDINGLY...AND ADDRESS PRECIPITATION POTENTIAL. THE WINDS WILL LIKELY BE THE MOST SIGNIFICANT IMPACT TODAY WITH GUSTS TO AROUND 50 MPH ALREADY IN WESTERN KANSAS...60 MPH IN WESTERN NEBRASKA...AND MORE THAN 100 MPH IN THE MOUNTAIN PASSES OF COLORADO. THE STORM SYSTEM CAUSING THESE WINDS WILL TRACK TO THE EAST THIS AFTERNOON AND EVENING...WITH A COLD FRONT EXPECTED TO ENTER THE NORTHWESTERN CORNER OF THE FORECAST AREA JUST AFTER NOON AND PASS THROUGH EAST CENTRAL KANSAS BY 6 PM. ALL MODEL GUIDANCE THIS MORNING CONTINUES TO SUGGEST THE POTENTIAL FOR STRONG WINDS TODAY...BUT THERE ARE NOW INDICATIONS THAT THESE WINDS WILL EXTEND ACROSS THE ENTIRE FORECAST AREA...AND MAY BE STRONGER YET IN NORTHERN PARTS OF THE FORECAST AREA. ALSO...SOUTHWEST WINDS AHEAD OF THE FRONT WILL BE BORDERLINE ON MEETING WIND ADVISORY CRITERIA SO HAVE INCLUDED THE ENTIRE AREA FROM NOON THROUGH 3 AM. THE PRIMARY CONCERN IN THE NEAR TERM WILL THEN BE THE POTENTIAL FOR GUSTS APPROACHING 60 MPH OR STRONGER DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. THERE IS ADMITTEDLY SOME MODERATE POTENTIAL FOR THIS TO HAPPEN...PARTICULARLY IN THE CONCORDIA... MARYSVILLE AND BELLEVILLE AREAS. NAM AND RUC SOUNDINGS ARE QUITE AGGRESSIVE IN FORECASTING WINDS AT THE TOP OF THE MIXED LAYER IN THE 50 TO 60 KT RANGE AT TIMES. IN ADDITION...THE ISALLOBARIC WIND COMPONENT WILL BE SUBSTANTIAL WITH A FORECAST PRESSURE RISE/FALL COUPLET APPROACHING 16 HPA ACROSS THE STATE OF KANSAS AND VERY STRONG PRESSURE GRADIENT ALREADY IN PLACE. WILL BE CLOSELY MONITORING THIS SYSTEM THROUGHOUT THE DAY FOR POTENTIAL HIGH WIND WARNING ISSUANCE (FOR 50+ KNOT WINDS). FURTHER COMPLICATING THIS FORECAST IS THE POTENTIAL FOR WIDESPREAD CLOUD COVER AND SHOWERS. IN FACT...MODELS SUGGEST SOME INSTABILITY AT THE TOP OF THE MIXED LAYER AND ABOVE 600 HPA WHICH COULD EFFECTIVELY CREATE HEAVY ENOUGH SHOWERS TO BRING SOME OF THE STRONGEST GUSTS DOWN TO THE SURFACE. ON THAT NOTE...THIS INSTABILITY...POWERFUL SYSTEM DYNAMICS...AND A HIGHER QUALITY MOISTURE POOL THAN PREVIOUSLY FORECAST SUGGEST THAT CHANCES FOR SCATTERED SHOWERS ARE INCREASING...ESPECIALLY NORTH...AND COULD NOT TOTALLY RULE OUT A FEW SNOW FLAKES OR EVEN A FEW LIGHTNING STRIKES. FIRE WEATHER ALSO REMAINS A CONCERN WITH SUCH POWERFUL WINDS. MIN RH VALUES STILL APPEAR TO BE LIMITED TO AROUND 30 PERCENT...AND SOME FUELS MAY BE LOCALLY MOIST GIVEN THE RECENT SNOW COVER IN PARTS OF THE AREA. NEEDLESS TO SAY HOWEVER...WINDS AT 50+ MPH WILL MAKE CONDITIONS DIFFICULT. BARJENBRUCH && .DISCUSSION... PRIMARY ATTENTION IN FORECAST PERIOD IS WIND AND FIRE WEATHER CONCERNS THIS AFTERNOON AND EVENING. WIND CONCERNS: UPPER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE INTO THE CENTRAL PLAINS THROUGHOUT THE DAY. STRENGTHENING PRESSURE GRADIENT WILL RESULT IN STRONG SURFACE WINDS OVER MUCH OF THE CWA TODAY. IN ADVANCE OF THE COLD FRONTAL PASSAGE...WINDS WILL INCREASE TO 20-24 KTS OVER EAST CENTRAL KANSAS BY LATE MORNING. THIS CORRIDOR OF STRONG WINDS WILL GRADUALLY SHIFT EASTWARD DURING THE EARLY AFTERNOON HOURS AS THE SFC FRONT APPROACHES. ANTICIPATE SPEEDS TO BE JUST UNDER WIND ADVISORY CRITERIA IN THIS AREA. BEHIND THE FRONTAL PASSAGE...CONFIDENCE IS HIGHER THAT AREAS ALONG AND WEST OF A LINE FROM HIAWATHA TO ABILENE WILL EXPERIENCE WIND SPEEDS GREATER THAN 25 KTS THIS AFTERNOON AND EVENING. IMMEDIATELY BEHIND THE BOUNDARY FROM 18-00Z...NEARLY DRY ADIABATIC LAPSE RATES WILL EXIST JUST ABOVE THE SFC TO H8. APPROXIMATELY 2KFT AGL...40 KTS ARE EXPECTED...WITH WIND DIRECTIONS FAIRLY UNIDIRECTIONAL THROUGH THE LOWEST 10KFT. 5 TO 8 HPA 3-HOUR PRESSURE RISES ARE EXPECTED BEHIND THE SFC TROUGH AXIS...WITH CROSS-ISOBARIC FLOW OVER MUCH OF NC KANSAS AND 50 UBARS/KM MAGNITUDE DURING PEAK MIXING. THE END RESULT WILL BE A 3-6 HOUR WINDOW OF WIND ADVISORY CONDITIONS OVER PORTIONS OF NC/NE KANSAS THIS AFTERNOON. ADDITIONALLY...HAVE SOME CONCERN THAT SHALLOW CONVECTION COULD DEVELOP BEHIND THE FRONT ACROSS NORTHERN KANSAS. WHILE THE PROBABILITY OF MEASURABLE RAINFALL ISN`T PARTICULARLY HIGH DUE TO EVAPORATION...THE VIRGA MAY ALLOW FOR ENHANCED NEGATIVELY BUOYANT WIND SPEEDS TO REACH THE SURFACE. THE AREA ALONG AND NORTH OF A CONCORDIA TO SENECA LINE WILL HAVE THE GREATEST PROBABLY OF SUCH A SCENARIO PLAYING OUT. BY EVENING...MIGHT SEE SOME AREAS WITH LIGHT RAIN OVER THE NORTHERN CWA ON THE BACKSIDE OF THE LOW. AS A SIDE NOTE...THE 06Z NAM CAME IN MUCH STRONGER WITH THE SYSTEM...WITH AN AGGRESSIVE SCENARIO OF WIND ADV CONDITIONS OVER MUCH OF THE CWA MUCH LATER THIS EVENING. CURRENTLY THIS IS AN OUTLIER BUT WILL NEED TO MONITOR TRENDS ON SUBSEQUENT OPERATIONAL RUNS IF OTHER SOLUTIONS BEGIN TO SUGGEST A MORE AGGRESSIVE SCENARIO. FIRE WEATHER: STRONG WINDS...LOW RELATIVE HUMIDITY...WARM TEMPERATURES AND DRY VEGETATION WILL MAKE FOR VERY HIGH FIRE DANGER ACROSS THE AREA THIS AFTERNOON. THE CWA LOOKS TO FALL SHORT OF RED FLAG CONDITIONS...WITH MINIMUM RELATIVE HUMIDITY VALUES AVERAGING IN THE UPPER 20S TO LOWER 30S PERCENT RANGE. WILL NEED TO BE MONITORED IF STRONGER MIXING YIELDS LOWER THAN ANTICIPATED DEWPOINTS. HIGHS THIS AFTERNOON WILL RANGE FROM THE MIDDLE 50S IN NC KANSAS TO THE MIDDLE 60S IN EC KANSAS. A FEW RECORD HIGHS MAY BE BROKEN TODAY IN PORTIONS OF NE/EC KANSAS...TOPEKA`S RECORD SITS AT 63 FOR TODAY. OTHERWISE IN THE FORECAST PERIOD...MUCH COOLER CONDITIONS ARE EXPECTED TO START 2012. COLD AIR ADVECTION WILL HOLD TEMPERATURES IN THE LOWER TO MIDDLE 40S ON SUNDAY AFTERNOON...WITH COLDER H85 TEMPERATURES ARRIVING ON MONDAY AS THE EASTERN TROUGH AMPLIFIES. THIS WILL RESULT IN COOLER READINGS ON MONDAY...WITH HIGHS IN THE MIDDLE TO UPPER 30S. THEREAFTER...TEMPERATURES WILL MODIFY THROUGH THE REMAINDER OF THE WORK WEEK...WITH 50S RETURNING WED-FRI AS UPPER LEVEL RIDGING BECOMES ESTABLISHED. WITH INITIAL NORTHWEST FLOW ALOFT...TRANSITIONING TO A RIDGING PATTERN...THE LOWER ATMOSPHERE WILL REMAIN QUITE DRY...RESULTING IN A DRY FORECAST FOR THE PERIOD. BLAIR && .AVIATION... SOUTH TO SOUTHWEST WINDS GUSTING UP TO 30 KTS WILL PERSIST THROUGH THE AFTERNOON IN ADVANCE OF A COLD FRONT. THE COLD FRONT WILL PASS THROUGH MHK AROUND 00Z AND TOP/FOE CLOSE TO 01Z WITH A SHIFT TO NORTHWEST WINDS. SIGNIFICANT GUSTS ARE POSSIBLE BEHIND THE COLD FRONT WITH OCCASIONAL GUSTS OF 40 TO 45 KTS EXPECTED AND SOME POTENTIAL FOR HIGHER GUSTS BETWEEN 00Z AND 06Z. THERE IS SOME POTENTIAL FOR MVFR CIGS FOR A 2-4 HOUR PERIOD BETWEEN 00Z AND 06Z AS WELL...BUT NOT CONFIDENT ENOUGH TO INCLUDE A TAF GROUP FOR THIS JUST YET. BARJENBRUCH && .TOP WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR KSZ008>012-020>024-026- 034>040-054>056-058-059. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1111 AM CST SAT DEC 31 2011 .UPDATE... HAVE UPDATED THE FORECAST THROUGH MIDNIGHT IN AN ATTEMPT TO NAIL DOWN THE EXPECTED WIND GUSTS AND RH VALUES...ADJUST THE WIND ADVISORY ACCORDINGLY...AND ADDRESS PRECIPITATION POTENTIAL. THE WINDS WILL LIKELY BE THE MOST SIGNIFICANT IMPACT TODAY WITH GUSTS TO AROUND 50 MPH ALREADY IN WESTERN KANSAS...60 MPH IN WESTERN NEBRASKA...AND MORE THAN 100 MPH IN THE MOUNTAIN PASSES OF COLORADO. THE STORM SYSTEM CAUSING THESE WINDS WILL TRACK TO THE EAST THIS AFTERNOON AND EVENING...WITH A COLD FRONT EXPECTED TO ENTER THE NORTHWESTERN CORNER OF THE FORECAST AREA JUST AFTER NOON AND PASS THROUGH EAST CENTRAL KANSAS BY 6 PM. ALL MODEL GUIDANCE THIS MORNING CONTINUES TO SUGGEST THE POTENTIAL FOR STRONG WINDS TODAY...BUT THERE ARE NOW INDICATIONS THAT THESE WINDS WILL EXTEND ACROSS THE ENTIRE FORECAST AREA...AND MAY BE STRONGER YET IN NORTHERN PARTS OF THE FORECAST AREA. ALSO...SOUTHWEST WINDS AHEAD OF THE FRONT WILL BE BORDERLINE ON MEETING WIND ADVISORY CRITERIA SO HAVE INCLUDED THE ENTIRE AREA FROM NOON THROUGH 3 AM. THE PRIMARY CONCERN IN THE NEAR TERM WILL THEN BE THE POTENTIAL FOR GUSTS APPROACHING 60 MPH OR STRONGER DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. THERE IS ADMITTEDLY SOME MODERATE POTENTIAL FOR THIS TO HAPPEN...PARTICULARLY IN THE CONCORDIA... MARYSVILLE AND BELLEVILLE AREAS. NAM AND RUC SOUNDINGS ARE QUITE AGGRESSIVE IN FORECASTING WINDS AT THE TOP OF THE MIXED LAYER IN THE 50 TO 60 KT RANGE AT TIMES. IN ADDITION...THE ISALLOBARIC WIND COMPONENT WILL BE SUBSTANTIAL WITH A FORECAST PRESSURE RISE/FALL COUPLET APPROACHING 16 HPA ACROSS THE STATE OF KANSAS AND VERY STRONG PRESSURE GRADIENT ALREADY IN PLACE. WILL BE CLOSELY MONITORING THIS SYSTEM THROUGHOUT THE DAY FOR POTENTIAL HIGH WIND WARNING ISSUANCE (FOR 50+ KNOT WINDS). FURTHER COMPLICATING THIS FORECAST IS THE POTENTIAL FOR WIDESPREAD CLOUD COVER AND SHOWERS. IN FACT...MODELS SUGGEST SOME INSTABILITY AT THE TOP OF THE MIXED LAYER AND ABOVE 600 HPA WHICH COULD EFFECTIVELY CREATE HEAVY ENOUGH SHOWERS TO BRING SOME OF THE STRONGEST GUSTS DOWN TO THE SURFACE. ON THAT NOTE...THIS INSTABILITY...POWERFUL SYSTEM DYNAMICS...AND A HIGHER QUALITY MOISTURE POOL THAN PREVIOUSLY FORECAST SUGGEST THAT CHANCES FOR SCATTERED SHOWERS ARE INCREASING...ESPECIALLY NORTH...AND COULD NOT TOTALLY RULE OUT A FEW SNOW FLAKES OR EVEN A FEW LIGHTNING STRIKES. FIRE WEATHER ALSO REMAINS A CONCERN WITH SUCH POWERFUL WINDS. MIN RH VALUES STILL APPEAR TO BE LIMITED TO AROUND 30 PERCENT...AND SOME FUELS MAY BE LOCALLY MOIST GIVEN THE RECENT SNOW COVER IN PARTS OF THE AREA. NEEDLESS TO SAY HOWEVER...WINDS AT 50+ MPH WILL MAKE CONDITIONS DIFFICULT. BARJENBRUCH && .DISCUSSION... PRIMARY ATTENTION IN FORECAST PERIOD IS WIND AND FIRE WEATHER CONCERNS THIS AFTERNOON AND EVENING. WIND CONCERNS: UPPER DISTURBANCE AND ASSOCIATED COLD FRONT WILL MOVE INTO THE CENTRAL PLAINS THROUGHOUT THE DAY. STRENGTHENING PRESSURE GRADIENT WILL RESULT IN STRONG SURFACE WINDS OVER MUCH OF THE CWA TODAY. IN ADVANCE OF THE COLD FRONTAL PASSAGE...WINDS WILL INCREASE TO 20-24 KTS OVER EAST CENTRAL KANSAS BY LATE MORNING. THIS CORRIDOR OF STRONG WINDS WILL GRADUALLY SHIFT EASTWARD DURING THE EARLY AFTERNOON HOURS AS THE SFC FRONT APPROACHES. ANTICIPATE SPEEDS TO BE JUST UNDER WIND ADVISORY CRITERIA IN THIS AREA. BEHIND THE FRONTAL PASSAGE...CONFIDENCE IS HIGHER THAT AREAS ALONG AND WEST OF A LINE FROM HIAWATHA TO ABILENE WILL EXPERIENCE WIND SPEEDS GREATER THAN 25 KTS THIS AFTERNOON AND EVENING. IMMEDIATELY BEHIND THE BOUNDARY FROM 18-00Z...NEARLY DRY ADIABATIC LAPSE RATES WILL EXIST JUST ABOVE THE SFC TO H8. APPROXIMATELY 2KFT AGL...40 KTS ARE EXPECTED...WITH WIND DIRECTIONS FAIRLY UNIDIRECTIONAL THROUGH THE LOWEST 10KFT. 5 TO 8 HPA 3-HOUR PRESSURE RISES ARE EXPECTED BEHIND THE SFC TROUGH AXIS...WITH CROSS-ISOBARIC FLOW OVER MUCH OF NC KANSAS AND 50 UBARS/KM MAGNITUDE DURING PEAK MIXING. THE END RESULT WILL BE A 3-6 HOUR WINDOW OF WIND ADVISORY CONDITIONS OVER PORTIONS OF NC/NE KANSAS THIS AFTERNOON. ADDITIONALLY...HAVE SOME CONCERN THAT SHALLOW CONVECTION COULD DEVELOP BEHIND THE FRONT ACROSS NORTHERN KANSAS. WHILE THE PROBABILITY OF MEASURABLE RAINFALL ISN`T PARTICULARLY HIGH DUE TO EVAPORATION...THE VIRGA MAY ALLOW FOR ENHANCED NEGATIVELY BUOYANT WIND SPEEDS TO REACH THE SURFACE. THE AREA ALONG AND NORTH OF A CONCORDIA TO SENECA LINE WILL HAVE THE GREATEST PROBABLY OF SUCH A SCENARIO PLAYING OUT. BY EVENING...MIGHT SEE SOME AREAS WITH LIGHT RAIN OVER THE NORTHERN CWA ON THE BACKSIDE OF THE LOW. AS A SIDE NOTE...THE 06Z NAM CAME IN MUCH STRONGER WITH THE SYSTEM...WITH AN AGGRESSIVE SCENARIO OF WIND ADV CONDITIONS OVER MUCH OF THE CWA MUCH LATER THIS EVENING. CURRENTLY THIS IS AN OUTLIER BUT WILL NEED TO MONITOR TRENDS ON SUBSEQUENT OPERATIONAL RUNS IF OTHER SOLUTIONS BEGIN TO SUGGEST A MORE AGGRESSIVE SCENARIO. FIRE WEATHER: STRONG WINDS...LOW RELATIVE HUMIDITY...WARM TEMPERATURES AND DRY VEGETATION WILL MAKE FOR VERY HIGH FIRE DANGER ACROSS THE AREA THIS AFTERNOON. THE CWA LOOKS TO FALL SHORT OF RED FLAG CONDITIONS...WITH MINIMUM RELATIVE HUMIDITY VALUES AVERAGING IN THE UPPER 20S TO LOWER 30S PERCENT RANGE. WILL NEED TO BE MONITORED IF STRONGER MIXING YIELDS LOWER THAN ANTICIPATED DEWPOINTS. HIGHS THIS AFTERNOON WILL RANGE FROM THE MIDDLE 50S IN NC KANSAS TO THE MIDDLE 60S IN EC KANSAS. A FEW RECORD HIGHS MAY BE BROKEN TODAY IN PORTIONS OF NE/EC KANSAS...TOPEKA`S RECORD SITS AT 63 FOR TODAY. OTHERWISE IN THE FORECAST PERIOD...MUCH COOLER CONDITIONS ARE EXPECTED TO START 2012. COLD AIR ADVECTION WILL HOLD TEMPERATURES IN THE LOWER TO MIDDLE 40S ON SUNDAY AFTERNOON...WITH COLDER H85 TEMPERATURES ARRIVING ON MONDAY AS THE EASTERN TROUGH AMPLIFIES. THIS WILL RESULT IN COOLER READINGS ON MONDAY...WITH HIGHS IN THE MIDDLE TO UPPER 30S. THEREAFTER...TEMPERATURES WILL MODIFY THROUGH THE REMAINDER OF THE WORK WEEK...WITH 50S RETURNING WED-FRI AS UPPER LEVEL RIDGING BECOMES ESTABLISHED. WITH INITIAL NORTHWEST FLOW ALOFT...TRANSITIONING TO A RIDGING PATTERN...THE LOWER ATMOSPHERE WILL REMAIN QUITE DRY...RESULTING IN A DRY FORECAST FOR THE PERIOD. BLAIR && .AVIATION... RELATIVELY DRY AIR IN THE LOWER ATMOSPHERE IS EXPECTED TO CREATE VFR CONDITIONS TODAY. MAIN CONCERN WILL BE WINDS WITH THE PRESSURE GRADIENT INCREASE THROUGH THE DAY. GUSTS UP TO 35 KTS ARE EXPECTED TO PERSIST WELL AFTER SUNSET BECAUSE OF THE PRESSURE GRADIENT AND A STRONG LOW LEVEL JET MOVING IN FROM THE NORTHWEST. THE GFS AND NAM ARE STARTING TO HINT AT A BRIEF CLOUD DECK COMING IN BEHIND THE FRONT BETWEEN 2 AND 3 KFT. OPTED TO KEEP AN OPTIMISTIC FORECAST AND LET THE NEXT SHIFTS SEE IF THIS PANS OUT. WOLTERS && .TOP WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR KSZ008>012-020>024-026- 034>040-054>056-058-059. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1233 PM EST SAT DEC 31 2011 UPDATED AVIATION DISCUSSION FOR 18Z TAFS .UPDATE...ISSUED AT 1138 AM EST SAT DEC 31 2011... DIDN/T MAKE ANY CHANGES TO THE GOING HEADLINES...BUT THERE MAY BE SOME CHANGES NEEDED AS THE LATEST 12Z MODELS RUNS HAVE BEEN ARRIVING. 12Z RUNS THAT HAVE ARRIVED SO FAR HAVE SHOWN THE H850-600 FGEN FORCED PCPN HANGING UP FARTHER WEST OVER WRN LK SUPERIOR THIS EVENING AND THEN PUSHING INTO GOGEBIC/ONTONAGON COUNTIES TOWARDS MIDNIGHT AND THEN CONTINUING INTO SUN MORNING. THUS...GOING WARNING LOOKS GOOD THERE. CONCERN ARRIVES FOR NRN HOUGHTON/KEWEENAW...ALONG WITH BARAGA/MARQUETTE COUNTIES FOR TONIGHT. TRENDS FOR TONIGHT HAVE SNOWS STAYING FAIRLY LIGHT...WITH ONLY AN INCH OR TWO OF ACCUMULATION AFTER MIDNIGHT FOR THE KEWEENAW AND TOWARDS MORNING FOR MARQUETTE/BARAGA AS THE SHORTWAVE BEGINS TO ROTATE NE AND STRENGTHENS THE LOW. WILL TAKE A CLOSER LOOK INTO WHAT TO DO FOR TONIGHT/S HEADLINES...BUT WILL CONTINUE TO EMPHASIZE THE NEAR BLIZZARD CONDITIONS FOR SUN AFTN INTO MON. LATEST TRENDS ARE ALSO SHOWING ADVY SNOW FOR DICKINSON/MENOMINEE/DELTA/SRN SCHOOLCRAFT AND WILL LIKELY NEED AT LEAST ADVY...BUT WINDS AND BLOWING SNOW COULD SUPPORT WARNING THERE FOR TOMORROW MORNING...BUT WANT TO SEE MOST OF THE 12Z RUNS BEFORE GOING WITH AT LEAST AN ADVY. && .SYNOPSIS...ISSUED AT 750 AM EST SAT DEC 31 2011... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW PATTERN OVER NAMERICA. THERE IS A NEAR ZONAL NRN BRANCH FLOW ACRS SRN CAN WITH A DISTURBANCE OF NOTE MOVING E THRU SASKATCHEWAN. OF NOTE THERE IS ALMOST A COMPLETE ABSENCE OF ARCTIC AIR IN THIS AREA...WITH THE LOWEST 00Z H85 TEMP ONLY -9C IN NRN BRITISH COLUMBIA. A MORE ACTIVE SRN BRANCH FLOW IS PRESENT IN THE CONUS. A FAIRLY DEEP TROF IS NOTED OVER THE GREAT LKS INTO THE OH RIVER VALLEY...SUPPORTING A SFC LO IN OH THAT IS MOVING E. UNDER AN UPR RDG IN THE CNTRL PLAINS...12Z-24Z H3 RISES OVER 200M ARE PRESENT... BUT THERE IS ONLY A WEAK SFC HI PRES RDG STRETCHING FM MN INTO WI ON THE NW FLANK OF THE SFC LO TO THE SE. LOCAL 00Z RAOBS SHOW SHARP SUBSIDENCE INVRN BTWN H875 AT GRB/APX AND H925 AT INL. THE SUB INVRN LYR IS RELATIVELY MOIST...SO LO CLDS ARE PRESENT OVER MUCH OF THE AREA. HOWEVER...THE LO CLDS HAVE DISSIPATED IN A SWATCH FM NE MN INTO NCNTRL WI AND OVER PARTS OF SCNTRL UPR MI. TEMPS IN THESE AREAS HAVE FALLEN AS LO AS 5 TO 10F. LOOKING FARTHER W...A VIGOROUS SHRTWV IS PLOWING THRU THE PAC NW...ACCOMPANIED BY 12Z-24Z H3 FALLS OVER 200M. RIGHT IN THE PATH OF THIS DISTURBANCE...A LINE OF SVR TS ACCOMPANIED BY SN STRUCK NEAR BOISE ID. && .DISCUSSION...ISSUED AT 750 AM EST SAT DEC 31 2011... MAIN FCST CONCERNS THIS PACKAGE FOCUS ON DETAILS OF UPCOMING SN STORM THAT IS FCST WITH DEVELOPMENT OF DEEP LO PRES SOMEWHERE NEAR UPR MI BY SUN. TDAY...A RELATIVELY QUIET PERIOD IS ON TAP FOR TODAY AS UPR RDG IN THE PLAINS DRIFTS E ACRS THE UPR LKS. WITH STRONGER SUBSIDENCE AHEAD OF THIS RDG...SUSPECT THE LO CLDS MAY BREAK UP A BIT EARLY THIS MRNG...UNLESS THE INVRN JUST SHARPENS AND CONTINUES TO TRAP THE LLVL MSTR. THE LO CLDS ARE LIKELY TO BE THE MOST RESILIENT OVER THE E NEAR LINGERING WEAK LO PRES TROF. THEN...NRN BRANCH SHRTWV IS FCST TO MOVE TO NEAR LK WINNIPEG WHILE THE STRONGER SRN BRANCH DISTURBANCE DIGS TO NEAR OMAHA BY 00Z SUN. THE STRENGTHENING SW FLOW AHEAD OF THESE FEATURES WL BRING MAINLY MID/HI CLDS INTO THE AREA WITH VERY DRY AT H85 LINGERING THRU THE DAY. MOST MODELS NOW GENERATE LTL OF NO PCPN OVER THE CWA THRU 00Z...SO RESTRICTED POPS TO THE FAR W CLOSER TO THE DEEPER MSTR FCST OVER MN/WRN LK SUP. EXPECT THE HIEST TEMPS INTO THE 30S OVER THE W NEAR LK SUP WHERE S WIND DOWNSLOPES. SINCE NAM WBLB ZERO HGT IS FCST TO BE AOA 1K FT IN THIS AREA OVER THE W...INCLUDED A MENTION OF RA/SN MIX WITH THE LGT PCPN EVEN THOUGH THE DRY AIR AT H85 WL TEND TO BRING ABOUT SOME EVAP COOLING. TNGT...THERE CONTINUES TO BE A LARGE SPREAD ON HOW QUICKLY THE SFC LO DEEPENS IN ASSOCIATION WITH MAINLY THE VIGOROUS SRN BRANCH DISTURBANCE NOW MOVING TOWARD THE NRN ROCKIES. CONSIDERING THE LACK OF ARCTIC AIR IN CAN AND THE SEPARATE BRANCHES OF FLOW OVER NAMERICA...NCEP FAVORS TRENDING AWAY FM THE CONSISTENTLY DEEPER GFS SCENARIO...WITH A BLEND OF THE 00Z NAM AND THE CONSISTENTLY WEAKER 12Z ECMWF. WHILE THE NRN BRANCH FEATURES DRIFT E THRU ONTARIO...THE 2 FAVORED MODELS SHOW THE SFC LO ASSOCIATED WITH THE SRN BRANCH SHRTWV REACHING NRN LK MI BY 12Z SUN...WITH NAM/ECMWF INTENSITY DOWN TO 993MB/999MB. EXPECT PCPN TO OVERSPREAD THE CWA W-E UNDER DPVA/UPR DVGC RELATED TO 12HR H5 FALLS UP TO 200M AND THE ARRIVAL OF MORE LLVL MSTR. SHARER H85-7 FGEN RELATED TO THE PASSAGE OF THE COLD FNT ASSOCIATED WITH THE NRN BRANCH DISTURBANCE/DEEPENING SRN BRANCH LO IS FCST TO ARRIVE AFT 06Z...SO EXPECT HIER POPS THEN. GRADUAL ARRIVAL OF COLDER AIR...H85 TEMPS ARE PROGGED TO FALL TO -8 TO -9C NEAR IWD BY 12Z SUN AS NRN BRANCH DISTURBANCE TAPS COLDER H85 AIR IN WRN CAN...WITH NW H85 FLOW IN THE PRESENCE OF DEEPER MSTR WL BRING SOME LK ENHANCED SN THERE. ALTHOUGH THE PCPN MAY BE MIXED WITH RA AT THE ONSET...THE COMBINATION OF DYNAMIC/EVAP COOLING WL CHANGE THE PCPN TO MAINLY SN FAIRLY QUICKLY EXCEPT NEAR THE LK MI SHORE. SUN/SUN NGT...AS THE NRN BRANCH DISTURBANCE GRADUALLY PHASES WITH THE SRN BRANCH SHRTWV...THE SFC LO IS FCST TO DEEPEN TO THE E OF UPR MI...MORE SLOWLY BY THE ECMWF TO 992MB...VS 989MB FOR THE NAM BY 00Z MON. BOTH MODELS SHOW THE LO DEEPENING TO ARND 987MB OVER WRN QUEBEC BY 12Z MON. COLDER AIR IS GRADUALLY ADVECTED INTO THE UPR GRT LKS... WITH H85 TEMPS PROGGED TO FALL TO -13C/-15C BY 00Z MON OVER WRN LK SUP AS H85 NW WINDS INCRS TO 40-50KTS IN THE WAKE OF THE LO TO THE E. THIS FLOW TENDS TO VEER MORE NNW ON SUN NGT FOLLOWING WHAT APPEARS TO THE PASSAGE OF THE ORIGINAL NRN BRANCH SHRTWV. THE ECMWF FCSTS H85 TEMPS SINKING AS LO AS -19C AT 12Z MON FOLLOWING THIS PASSAGE. ALTHOUGH BOTH THE NAM AND ECWMF...ESPECIALLY THE ECMWF... SHOW SOME DRIER AIR IN THE MID LVLS IMPACTING THE FAR W FOR A TIME ON SUN AS THE DEEPER QVECTOR CNVGC AND UPR DVGC LIFT AWAY TO THE ENE...THE COMBINATION OF LLVL CYC FLOW/DEEP MSTR IMPACT THE CWA THRU THIS TIME. THE ARRIVAL OF THE COLDER AIR WL ALSO TEND TO INCRS WIND SPEEDS...RESULTING IN CONSIDERABLE BLSN AS WELL AS THE LK ENHANCED SN WITH CONSIDERABLE OMEGA WITHIN THE DGZ. EXPECT NO MORE THAN SCT -SHSN OVER THE SCNTRL WITH DOWNSLOPE WIND...BUT SOME BLOWING SN IS LIKELY EVEN THERE...ESPECIALLY IN AREAS THAT PICK UP A FEW INCHES TNGT. MON/MON NGT...A NNW FLOW OF COLD AIR WL PERSIST THRU THIS TIME WITHIN H85 THERMAL TROF AND TEMPS FALLING NEAR -20C PER THE 12Z ECMWF. HOWEVER...AS THE CLOSED LO TO THE E EXITS FARTHER AWAY... MODELS IN GOOD AGREEMENT SHOWING DEEPER MSTR EXITING/INVRN BASE SUBSIDING W-E ON MON WITH THE ONSET OF DNVA/LARGE SCALE QVECTOR DVGC/SUBSIDENCE UNDER H5 RISES UP TO 180M AT IWD BTWN 18Z MON AND 06Z TUE. SO SHSN INTENSITY SHOULD DIMINISH W-E...BUT BE MORE RESILIENT OVER THE E WITH LONGER DURATION OF NLY FLOW/LOWER HGTS/ LOWER H85 TEMPS. WITH WEAKENING PRES GRADIENT...EXPECT THE BLSN TO SLOWLY SUBSIDE W-E AS WELL. SINCE SKIES WL LIKELY CLEAR MON NGT OVER AT LEAST THE W HALF...TENDED TO GO QUITE A BIT LOWER FOR MIN TEMPS WITH SFC RDG AXIS/LGT WINDS ARRIVING AND PWAT UNDER 50 PCT OF NORMAL. AS FAR AS HEADLINES ARE CONCERNED...OPTED TO UPGRADE WATCHES TO WRNGS OVER THE W HALF WHERE SGFNT SN WL BE FALLING IN THE 2ND PERIOD AND POSSIBLY IMPACT NEW YEARS EVE CELEBRATIONS. OPTED TO KEEP WATCH GOING FOR AREAS E OF MQT AS THE SGNFT WX WL NOT DEVELOP UNTIL THE 3RD PERIOD. THE BLIZZARD WATCH FOR THE NW ZNS THAT BEGAN AT 06Z PRESENTED A QUANDARY BECAUSE THE WX TNGT WL NOT MEET BLIZZARD CRITERIA FM WHEN THE ACCUMULATING SN WL ARRIVE ARND 03Z THRU AT LEAST 12Z SUN. SO OPTED TO GO WITH A WINTER STORM WRNG THERE. SINCE BLIZZARD CONDITIONS ARE LIKELY ON SUN/MON...LATER SHIFTS WL LIKELY NEED TO UPGRADE THE WRNG TO A BLIZZARD. DID HIGHLIGHT THE ONSET OF BLIZZARD CONDITONS ON SUN IN THE STATEMENT. THE WATCH FOR E OF MQT MAY ALSO NEED TO BE UPGRADED TO A BLIZZARD WRNG AT SOME TIME WITH SHSN/WIND GUSTS UP TO 60 MPH/EXTENSIVE BLOWING SN LIKELY THERE SUN AFTN INTO MON NGT. FOR THE EXTENDED FORECAST... FEW CHANGES WERE DEEMED NECESSARY...AS THE FORECAST REMAINED A BLEND OF AVAILABLE MODEL DATA. STARTING AT 12Z TUESDAY THE 500MB MAP SHOWS THE DEEP TROUGH SET UP OVER THE LOWER GREAT LAKES AND NEW ENGLAND STATES...WITH A SIGNIFICANT RIDGE BUILDING OVERHEAD. THE 500MB RIDGE WILL BECOME SUPPRESSED TUESDAY NIGHT...IN RESPONSE TO A OPEN WAVE SNEAKING IN FROM THE WEST. THE 00Z RUNS OF THE CANADIAN/ECMWF AND GFS ALL HAVE THIS FEATURE...WITH MINOR DIFFERENCES. THE 31/00Z RUN OF THE ECMWF TRIES TO CLOSE THIS FEATURE OFF ACROSS LAKE SUPERIOR AT 06Z WEDNESDAY...BEFORE IT SINKS TO THE LOWER GREAT LAKES. THE CANADIAN IS SIMILAR...BUT APPROX 250MI NW OF THE ECMWF WITH THIS FEATURE. THE RESULT IS A MORE PROGRESSIVE GFS. THIS SHOWS UP AT THE SFC TOO...WITH THE COLD FRONT/TROUGH OFF THE GFS SPLITTING THE CWA IN HALF AT 06Z WEDNESDAY. THE ECMWF IS CLOSER TO 12Z WEDNESDAY. STILL...MOST MODELS DO INDICATE RIDGING ALOFT AGAIN FOR WEDNESDAY THROUGH THE DAY FRIDAY. THE EXCEPTION TO THIS IS THE SLOWER CANADIAN RUN...WHICH STRENGTHENS THE 500MB LOW ACROSS QUEBEC AND LEADS TO A SLOW DOWN WHEN COMPARED TO THE OTHER MODELS OF AROUND 6HRS. THE NEXT FEATURE OF INTEREST AT THE SFC LOOKS TO BE OVER S CENTRAL CANADA FRIDAY MORNING...AND MAY CROSS OVER OR JUST NORTH OF LAKE SUPERIOR FRIDAY AFTERNOON/EVENING. WILL NOT CONCENTRATE OF THIS NEXT SYSTEM...DUE TO THE MODERATE CONFIDENCE. && .AVIATION /FOR THE 18Z TAF ISSUANCE/... LOW PRESSURE SYSTEM DEVELOPING IN THE NRN/CNTRL PLAINS WILL BRING DETERIORATING CONDITIONS AT THE TAF SITES THIS EVENING THROUGH THE END OF THE TAF PERIOD. AREA OF LOW CLOUDS AND FOG IN CNTRL WI WILL SLOWLY ADVECT NORTH LATE THIS AFTN AND EVENING AND LEAD TO LOW END MVFR CIGS AT ALL SITES THROUGH THE EVENING. KSAW HAS THE BEST CHANCE OF SEEING FOG THIS EVENING AND COULD GO LOWER THAN FCST WITH THE FAVORABLE SSE UPSLOPE WINDS...BUT THINK WINDS WILL BE STRONG ENOUGH TO KEEP VSBY FROM GOING TOO LOW. OTHERWISE...-SN WILL DEVELOP THIS EVENING AT KIWD AND SLOWLY SHIFT E THROUGH THE NIGHT. VSBYS SHOULD BE BELOW ALT LANDING MINS FOR THE SITES IN THE STRONGEST SNOW BAND THAT AFFECTS EACH OF THE SITES OVERNIGHT INTO SUN MORNING. INCREASING NW WINDS ON SUN...WITH GUSTS APPROACHING 40KTS BY THE END OF THE TAF PERIOD AT KCMX/KSAW...WILL LEAD TO CONSIDERABLE BLOWING/DRIFTING SNOW AND PUT VSBYS NEAR AIRFIELD LANDING MINS. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... LOWER GREAT LAKES LOW PRESSURE WILL EXIT TO THE NEW ENGLAND SEABOARD TODAY. IN ITS WAKE...LOW PRESSURE STRETCHING FROM WESTERN MANITOBA THROUGH THE DAKOTAS CAN BE EXPECTED TO DEEPEN NEAR NORTHERN LM SUNDAY MORNING...BEFORE SHIFTING ACROSS QUEBEC MONDAY...WHILE KEEPING A SIGNIFICANT TROUGH ACROSS LS AND UPPER MI. AHEAD OF STRONG HIGH PRESSURE OVER THE PLAINS STATES MONDAY MORNING WORKING A RIDGE WEST TO EAST ACROSS LS TUESDAY...STRONG N TO NW STORM FORCE WINDS LIKELY CENTRAL AND EAST SUNDAY AFTERNOON THROUGH MONDAY. THE RUSH OF COLD AIR AND HIGH WAVES WILL RESULT IN PERIODS OF MODERATE TO HEAVY FREEZING SPRAY AS WELL. A LOW PRESSURE SYSTEM OVER CENTRAL CANADA TUESDAY AFTERNOON WILL SHIFT SOUTHEASTWARD INTO HUDSON BAY...DRAGGING A TROUGH OVER THE UPPER GREAT LAKES ON WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER STORM WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 7 PM EST /6 PM CST/ MONDAY FOR MIZ001>003-009-084. WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT FOR MIZ006-007-085. WINTER STORM WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY FOR MIZ004-005. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST MONDAY FOR MIZ010. LAKE SUPERIOR... STORM WARNING FROM 7 AM SUNDAY TO 10 PM EST MONDAY FOR LSZ264>267. HEAVY FREEZING SPRAY WATCH FROM SUNDAY EVENING THROUGH TUESDAY MORNING FOR LSZ162-263>267. STORM WARNING FROM 11 AM SUNDAY TO 10 PM EST MONDAY FOR LSZ248>251. STORM WARNING FROM 11 AM SUNDAY TO 4 PM EST MONDAY FOR LSZ243>247. STORM WARNING FROM 11 AM EST /10 AM CST/ SUNDAY TO 7 AM EST /6 AM CST/ MONDAY FOR LSZ241-242. GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 11 AM EST /10 AM CST/ MONDAY FOR LSZ240. GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 1 PM EST /NOON CST/ MONDAY FOR LSZ162. STORM WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ263. LAKE MICHIGAN... GALE WARNING FROM 5 AM SUNDAY TO 1 AM EST TUESDAY FOR LMZ221-248- 250. && $$ UPDATE...SRF SYNOPSIS...KC DISCUSSION...KC EXTENDED...KF AVIATION...SRF MARINE...KF
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1138 AM EST SAT DEC 31 2011 .UPDATE... DIDN/T MAKE ANY CHANGES TO THE GOING HEADLINES...BUT THERE MAY BE SOME CHANGES NEEDED AS THE LATEST 12Z MODELS RUNS HAVE BEEN ARRIVING. 12Z RUNS THAT HAVE ARRIVED SO FAR HAVE SHOWN THE H850-600 FGEN FORCED PCPN HANGING UP FARTHER WEST OVER WRN LK SUPERIOR THIS EVENING AND THEN PUSHING INTO GOGEBIC/ONTONAGON COUNTIES TOWARDS MIDNIGHT AND THEN CONTINUING INTO SUN MORNING. THUS...GOING WARNING LOOKS GOOD THERE. CONCERN ARRIVES FOR NRN HOUGHTON/KEWEENAW...ALONG WITH BARAGA/MARQUETTE COUNTIES FOR TONIGHT. TRENDS FOR TONIGHT HAVE SNOWS STAYING FAIRLY LIGHT...WITH ONLY AN INCH OR TWO OF ACCUMULATION AFTER MIDNIGHT FOR THE KEWEENAW AND TOWARDS MORNING FOR MARQUETTE/BARAGA AS THE SHORTWAVE BEGINS TO ROTATE NE AND STRENGTHENS THE LOW. WILL TAKE A CLOSER LOOK INTO WHAT TO DO FOR TONIGHT/S HEADLINES...BUT WILL CONTINUE TO EMPHASIZE THE NEAR BLIZZARD CONDITIONS FOR SUN AFTN INTO MON. LATEST TRENDS ARE ALSO SHOWING ADVY SNOW FOR DICKINSON/MENOMINEE/DELTA/SRN SCHOOLCRAFT AND WILL LIKELY NEED AT LEAST ADVY...BUT WINDS AND BLOWING SNOW COULD SUPPORT WARNING THERE FOR TOMORROW MORNING...BUT WANT TO SEE MOST OF THE 12Z RUNS BEFORE GOING WITH AT LEAST AN ADVY. && PREV DISCUSSION...ISSUED AT 750 AM EST SAT DEC 31 2011... .SYNOPSIS... 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW PATTERN OVER NAMERICA. THERE IS A NEAR ZONAL NRN BRANCH FLOW ACRS SRN CAN WITH A DISTURBANCE OF NOTE MOVING E THRU SASKATCHEWAN. OF NOTE THERE IS ALMOST A COMPLETE ABSENCE OF ARCTIC AIR IN THIS AREA...WITH THE LOWEST 00Z H85 TEMP ONLY -9C IN NRN BRITISH COLUMBIA. A MORE ACTIVE SRN BRANCH FLOW IS PRESENT IN THE CONUS. A FAIRLY DEEP TROF IS NOTED OVER THE GREAT LKS INTO THE OH RIVER VALLEY...SUPPORTING A SFC LO IN OH THAT IS MOVING E. UNDER AN UPR RDG IN THE CNTRL PLAINS...12Z-24Z H3 RISES OVER 200M ARE PRESENT... BUT THERE IS ONLY A WEAK SFC HI PRES RDG STRETCHING FM MN INTO WI ON THE NW FLANK OF THE SFC LO TO THE SE. LOCAL 00Z RAOBS SHOW SHARP SUBSIDENCE INVRN BTWN H875 AT GRB/APX AND H925 AT INL. THE SUB INVRN LYR IS RELATIVELY MOIST...SO LO CLDS ARE PRESENT OVER MUCH OF THE AREA. HOWEVER...THE LO CLDS HAVE DISSIPATED IN A SWATCH FM NE MN INTO NCNTRL WI AND OVER PARTS OF SCNTRL UPR MI. TEMPS IN THESE AREAS HAVE FALLEN AS LO AS 5 TO 10F. LOOKING FARTHER W...A VIGOROUS SHRTWV IS PLOWING THRU THE PAC NW...ACCOMPANIED BY 12Z-24Z H3 FALLS OVER 200M. RIGHT IN THE PATH OF THIS DISTURBANCE...A LINE OF SVR TS ACCOMPANIED BY SN STRUCK NEAR BOISE ID. && .DISCUSSION... MAIN FCST CONCERNS THIS PACKAGE FOCUS ON DETAILS OF UPCOMING SN STORM THAT IS FCST WITH DEVELOPMENT OF DEEP LO PRES SOMEWHERE NEAR UPR MI BY SUN. TDAY...A RELATIVELY QUIET PERIOD IS ON TAP FOR TODAY AS UPR RDG IN THE PLAINS DRIFTS E ACRS THE UPR LKS. WITH STRONGER SUBSIDENCE AHEAD OF THIS RDG...SUSPECT THE LO CLDS MAY BREAK UP A BIT EARLY THIS MRNG...UNLESS THE INVRN JUST SHARPENS AND CONTINUES TO TRAP THE LLVL MSTR. THE LO CLDS ARE LIKELY TO BE THE MOST RESILIENT OVER THE E NEAR LINGERING WEAK LO PRES TROF. THEN...NRN BRANCH SHRTWV IS FCST TO MOVE TO NEAR LK WINNIPEG WHILE THE STRONGER SRN BRANCH DISTURBANCE DIGS TO NEAR OMAHA BY 00Z SUN. THE STRENGTHENING SW FLOW AHEAD OF THESE FEATURES WL BRING MAINLY MID/HI CLDS INTO THE AREA WITH VERY DRY AT H85 LINGERING THRU THE DAY. MOST MODELS NOW GENERATE LTL OF NO PCPN OVER THE CWA THRU 00Z...SO RESTRICTED POPS TO THE FAR W CLOSER TO THE DEEPER MSTR FCST OVER MN/WRN LK SUP. EXPECT THE HIEST TEMPS INTO THE 30S OVER THE W NEAR LK SUP WHERE S WIND DOWNSLOPES. SINCE NAM WBLB ZERO HGT IS FCST TO BE AOA 1K FT IN THIS AREA OVER THE W...INCLUDED A MENTION OF RA/SN MIX WITH THE LGT PCPN EVEN THOUGH THE DRY AIR AT H85 WL TEND TO BRING ABOUT SOME EVAP COOLING. TNGT...THERE CONTINUES TO BE A LARGE SPREAD ON HOW QUICKLY THE SFC LO DEEPENS IN ASSOCIATION WITH MAINLY THE VIGOROUS SRN BRANCH DISTURBANCE NOW MOVING TOWARD THE NRN ROCKIES. CONSIDERING THE LACK OF ARCTIC AIR IN CAN AND THE SEPARATE BRANCHES OF FLOW OVER NAMERICA...NCEP FAVORS TRENDING AWAY FM THE CONSISTENTLY DEEPER GFS SCENARIO...WITH A BLEND OF THE 00Z NAM AND THE CONSISTENTLY WEAKER 12Z ECMWF. WHILE THE NRN BRANCH FEATURES DRIFT E THRU ONTARIO...THE 2 FAVORED MODELS SHOW THE SFC LO ASSOCIATED WITH THE SRN BRANCH SHRTWV REACHING NRN LK MI BY 12Z SUN...WITH NAM/ECMWF INTENSITY DOWN TO 993MB/999MB. EXPECT PCPN TO OVERSPREAD THE CWA W-E UNDER DPVA/UPR DVGC RELATED TO 12HR H5 FALLS UP TO 200M AND THE ARRIVAL OF MORE LLVL MSTR. SHARER H85-7 FGEN RELATED TO THE PASSAGE OF THE COLD FNT ASSOCIATED WITH THE NRN BRANCH DISTURBANCE/DEEPENING SRN BRANCH LO IS FCST TO ARRIVE AFT 06Z...SO EXPECT HIER POPS THEN. GRADUAL ARRIVAL OF COLDER AIR...H85 TEMPS ARE PROGGED TO FALL TO -8 TO -9C NEAR IWD BY 12Z SUN AS NRN BRANCH DISTURBANCE TAPS COLDER H85 AIR IN WRN CAN...WITH NW H85 FLOW IN THE PRESENCE OF DEEPER MSTR WL BRING SOME LK ENHANCED SN THERE. ALTHOUGH THE PCPN MAY BE MIXED WITH RA AT THE ONSET...THE COMBINATION OF DYNAMIC/EVAP COOLING WL CHANGE THE PCPN TO MAINLY SN FAIRLY QUICKLY EXCEPT NEAR THE LK MI SHORE. SUN/SUN NGT...AS THE NRN BRANCH DISTURBANCE GRADUALLY PHASES WITH THE SRN BRANCH SHRTWV...THE SFC LO IS FCST TO DEEPEN TO THE E OF UPR MI...MORE SLOWLY BY THE ECMWF TO 992MB...VS 989MB FOR THE NAM BY 00Z MON. BOTH MODELS SHOW THE LO DEEPENING TO ARND 987MB OVER WRN QUEBEC BY 12Z MON. COLDER AIR IS GRADUALLY ADVECTED INTO THE UPR GRT LKS... WITH H85 TEMPS PROGGED TO FALL TO -13C/-15C BY 00Z MON OVER WRN LK SUP AS H85 NW WINDS INCRS TO 40-50KTS IN THE WAKE OF THE LO TO THE E. THIS FLOW TENDS TO VEER MORE NNW ON SUN NGT FOLLOWING WHAT APPEARS TO THE PASSAGE OF THE ORIGINAL NRN BRANCH SHRTWV. THE ECMWF FCSTS H85 TEMPS SINKING AS LO AS -19C AT 12Z MON FOLLOWING THIS PASSAGE. ALTHOUGH BOTH THE NAM AND ECWMF...ESPECIALLY THE ECMWF... SHOW SOME DRIER AIR IN THE MID LVLS IMPACTING THE FAR W FOR A TIME ON SUN AS THE DEEPER QVECTOR CNVGC AND UPR DVGC LIFT AWAY TO THE ENE...THE COMBINATION OF LLVL CYC FLOW/DEEP MSTR IMPACT THE CWA THRU THIS TIME. THE ARRIVAL OF THE COLDER AIR WL ALSO TEND TO INCRS WIND SPEEDS...RESULTING IN CONSIDERABLE BLSN AS WELL AS THE LK ENHANCED SN WITH CONSIDERABLE OMEGA WITHIN THE DGZ. EXPECT NO MORE THAN SCT -SHSN OVER THE SCNTRL WITH DOWNSLOPE WIND...BUT SOME BLOWING SN IS LIKELY EVEN THERE...ESPECIALLY IN AREAS THAT PICK UP A FEW INCHES TNGT. MON/MON NGT...A NNW FLOW OF COLD AIR WL PERSIST THRU THIS TIME WITHIN H85 THERMAL TROF AND TEMPS FALLING NEAR -20C PER THE 12Z ECMWF. HOWEVER...AS THE CLOSED LO TO THE E EXITS FARTHER AWAY... MODELS IN GOOD AGREEMENT SHOWING DEEPER MSTR EXITING/INVRN BASE SUBSIDING W-E ON MON WITH THE ONSET OF DNVA/LARGE SCALE QVECTOR DVGC/SUBSIDENCE UNDER H5 RISES UP TO 180M AT IWD BTWN 18Z MON AND 06Z TUE. SO SHSN INTENSITY SHOULD DIMINISH W-E...BUT BE MORE RESILIENT OVER THE E WITH LONGER DURATION OF NLY FLOW/LOWER HGTS/ LOWER H85 TEMPS. WITH WEAKENING PRES GRADIENT...EXPECT THE BLSN TO SLOWLY SUBSIDE W-E AS WELL. SINCE SKIES WL LIKELY CLEAR MON NGT OVER AT LEAST THE W HALF...TENDED TO GO QUITE A BIT LOWER FOR MIN TEMPS WITH SFC RDG AXIS/LGT WINDS ARRIVING AND PWAT UNDER 50 PCT OF NORMAL. AS FAR AS HEADLINES ARE CONCERNED...OPTED TO UPGRADE WATCHES TO WRNGS OVER THE W HALF WHERE SGFNT SN WL BE FALLING IN THE 2ND PERIOD AND POSSIBLY IMPACT NEW YEARS EVE CELEBRATIONS. OPTED TO KEEP WATCH GOING FOR AREAS E OF MQT AS THE SGNFT WX WL NOT DEVELOP UNTIL THE 3RD PERIOD. THE BLIZZARD WATCH FOR THE NW ZNS THAT BEGAN AT 06Z PRESENTED A QUANDARY BECAUSE THE WX TNGT WL NOT MEET BLIZZARD CRITERIA FM WHEN THE ACCUMULATING SN WL ARRIVE ARND 03Z THRU AT LEAST 12Z SUN. SO OPTED TO GO WITH A WINTER STORM WRNG THERE. SINCE BLIZZARD CONDITIONS ARE LIKELY ON SUN/MON...LATER SHIFTS WL LIKELY NEED TO UPGRADE THE WRNG TO A BLIZZARD. DID HIGHLIGHT THE ONSET OF BLIZZARD CONDITONS ON SUN IN THE STATEMENT. THE WATCH FOR E OF MQT MAY ALSO NEED TO BE UPGRADED TO A BLIZZARD WRNG AT SOME TIME WITH SHSN/WIND GUSTS UP TO 60 MPH/EXTENSIVE BLOWING SN LIKELY THERE SUN AFTN INTO MON NGT. FOR THE EXTENDED FORECAST... FEW CHANGES WERE DEEMED NECESSARY...AS THE FORECAST REMAINED A BLEND OF AVAILABLE MODEL DATA. STARTING AT 12Z TUESDAY THE 500MB MAP SHOWS THE DEEP TROUGH SET UP OVER THE LOWER GREAT LAKES AND NEW ENGLAND STATES...WITH A SIGNIFICANT RIDGE BUILDING OVERHEAD. THE 500MB RIDGE WILL BECOME SUPPRESSED TUESDAY NIGHT...IN RESPONSE TO A OPEN WAVE SNEAKING IN FROM THE WEST. THE 00Z RUNS OF THE CANADIAN/ECMWF AND GFS ALL HAVE THIS FEATURE...WITH MINOR DIFFERENCES. THE 31/00Z RUN OF THE ECMWF TRIES TO CLOSE THIS FEATURE OFF ACROSS LAKE SUPERIOR AT 06Z WEDNESDAY...BEFORE IT SINKS TO THE LOWER GREAT LAKES. THE CANADIAN IS SIMILAR...BUT APPROX 250MI NW OF THE ECMWF WITH THIS FEATURE. THE RESULT IS A MORE PROGRESSIVE GFS. THIS SHOWS UP AT THE SFC TOO...WITH THE COLD FRONT/TROUGH OFF THE GFS SPLITTING THE CWA IN HALF AT 06Z WEDNESDAY. THE ECMWF IS CLOSER TO 12Z WEDNESDAY. STILL...MOST MODELS DO INDICATE RIDGING ALOFT AGAIN FOR WEDNESDAY THROUGH THE DAY FRIDAY. THE EXCEPTION TO THIS IS THE SLOWER CANADIAN RUN...WHICH STRENGTHENS THE 500MB LOW ACROSS QUEBEC AND LEADS TO A SLOW DOWN WHEN COMPARED TO THE OTHER MODELS OF AROUND 6HRS. THE NEXT FEATURE OF INTEREST AT THE SFC LOOKS TO BE OVER S CENTRAL CANADA FRIDAY MORNING...AND MAY CROSS OVER OR JUST NORTH OF LAKE SUPERIOR FRIDAY AFTERNOON/EVENING. WILL NOT CONCENTRATE OF THIS NEXT SYSTEM...DUE TO THE MODERATE CONFIDENCE. && .AVIATION /FOR THE 06Z TAF ISSUANCE/... EXPECT INCREASING SOUTHERLY WINDS TODAY...OUT AHEAD OF AN APPROACHING LOW ACROSS THE NORTHERN PLAINS. ALTHOUGH THE SPECIFIC TIMING AND TRACK OF THIS LOW REMAINS A BIT UNCERTAIN...IT SHOULD SLIDE ACROSS CENTRAL/NORTHERN LAKE MICHIGAN DURING THE DAYLIGHT HOURS SUNDAY MORNING. AT THIS TIME IT STILL LOOKS REASONABLE FOR IWD AND CMX TO FALL TO IFR AROUND 02/03Z AS THE TROUGH CROSSES AND COLDER AIR AOB -3C RUSHES IN /WITH LOW PRESSURE EXTENDING FROM ONTARIO THROUGH SW WISCONSIN AROUND 03Z/. THIS SHOULD TIME OUT FOR 07Z FOR SIMILAR CONDITIONS AT SAW...BEFORE WINDS BEGIN TO PICK UP TOWARD SUNRISE SUNDAY AT IWD AND SAW...WITH BLSN LIKELY NEEDING TO BE ADDED TO THE TAFS WITH THE NEXT UPDATE/AMENDMENT. AS NOTED IN THE PREVIOUS DISCUSSION WITH CONTINUED STRONG N-NW FLOW AT CMX...ADVERSE CONDITIONS AT OR BLO AIRPORT MINS SHOULD CONTINUE INTO MONDAY. && .MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/... LOWER GREAT LAKES LOW PRESSURE WILL EXIT TO THE NEW ENGLAND SEABOARD TODAY. IN ITS WAKE...LOW PRESSURE STRETCHING FROM WESTERN MANITOBA THROUGH THE DAKOTAS CAN BE EXPECTED TO DEEPEN NEAR NORTHERN LM SUNDAY MORNING...BEFORE SHIFTING ACROSS QUEBEC MONDAY...WHILE KEEPING A SIGNIFICANT TROUGH ACROSS LS AND UPPER MI. AHEAD OF STRONG HIGH PRESSURE OVER THE PLAINS STATES MONDAY MORNING WORKING A RIDGE WEST TO EAST ACROSS LS TUESDAY...STRONG N TO NW STORM FORCE WINDS LIKELY CENTRAL AND EAST SUNDAY AFTERNOON THROUGH MONDAY. THE RUSH OF COLD AIR AND HIGH WAVES WILL RESULT IN PERIODS OF MODERATE TO HEAVY FREEZING SPRAY AS WELL. A LOW PRESSURE SYSTEM OVER CENTRAL CANADA TUESDAY AFTERNOON WILL SHIFT SOUTHEASTWARD INTO HUDSON BAY...DRAGGING A TROUGH OVER THE UPPER GREAT LAKES ON WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER STORM WARNING FROM 10 PM EST /9 PM CST/ THIS EVENING TO 7 PM EST /6 PM CST/ MONDAY FOR MIZ001>003-009-084. WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE MONDAY NIGHT FOR MIZ006-007-085. WINTER STORM WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY FOR MIZ004-005. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO NOON CST MONDAY FOR MIZ010. LAKE SUPERIOR... STORM WARNING FROM 7 AM SUNDAY TO 10 PM EST MONDAY FOR LSZ264>267. HEAVY FREEZING SPRAY WATCH FROM SUNDAY EVENING THROUGH TUESDAY MORNING FOR LSZ162-263>267. STORM WARNING FROM 11 AM SUNDAY TO 10 PM EST MONDAY FOR LSZ248>251. STORM WARNING FROM 11 AM SUNDAY TO 4 PM EST MONDAY FOR LSZ243>247. STORM WARNING FROM 11 AM EST /10 AM CST/ SUNDAY TO 7 AM EST /6 AM CST/ MONDAY FOR LSZ241-242. GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 11 AM EST /10 AM CST/ MONDAY FOR LSZ240. GALE WARNING FROM 5 AM EST /4 AM CST/ SUNDAY TO 1 PM EST /NOON CST/ MONDAY FOR LSZ162. STORM WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR LSZ263. LAKE MICHIGAN... GALE WARNING FROM 5 AM SUNDAY TO 1 AM EST TUESDAY FOR LMZ221-248- 250. && $$ UPDATE...SRF SYNOPSIS...KC DISCUSSION...KC EXTENDED...KF AVIATION...KF MARINE...KF
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
243 PM CST SAT DEC 31 2011 .DISCUSSION... IT LOOKS LIKE THE BEST WINDS ARE PASSING SOUTH AND WEST OF THE FCST AREA THIS AFTERNOON. THE PV15 PRESSURE SFC IS NOTICEABLY FARTHER SOUTH ON SATELLITE AND IN THE RUC THAN PREVIOUS MODEL SOLNS SUGGESTED. IT APPEARS THE ENTIRE WIND FIELD HAS SHIFTED SOUTHWEST ACROSS THE FAR SRN NEB PANHANDLE...NERN COLO AND WRN KS. THUS THE HIGH WIND WARNING AND PARTS OF THE WIND ADVISORY MAY BE CANCELLED EITHER LATE THIS AFTERNOON OR EARLY THIS EVENING. THE MODELS ALSO MOVE A PRETTY GOOD AREA OF RAIN AND SNOW FARTHER SOUTH THROUGH SWRN NEB. THIS PCPN SHOULD EXIT THE FCST AREA BY AROUND 03Z ACCORDING TO THE HRRR WHICH HAS SHOWN GOOD SKILL TODAY WITH PCPN FCSTS BUT NOT HIGH WIND GUSTS WHICH NEVER MATERIALIZED AS EXPECTED. GENERALLY CLEAR SKIES ARE EXPECTED AREA WIDE BY ROUGHLY 03Z-06Z AND STRONG PACIFIC HIGH PRESSURE WILL BUILD SLOWLY INTO THE NRN AND CNTL PLAINS SUNDAY. ANOTHER WINDY DAY IS EXPECTED ALONG AND EAST OF HIGHWAY 83 AND THE BEST GUESS USING MET/MAV GUIDANCE AND 500M AGL WINDS IS SPEEDS WILL BE 25 TO 30 MPH WITH GUSTS TO 40 MPH...JUST BELOW WIND ADVISORY CRITERIA. PACIFIC HIGH PRESSURE WILL STRENGTHEN DIRECTLY ACROSS THE FCST AREA SUNDAY NIGHT AND MONDAY MORNING PRODUCING LOWS IN THE SINGLE DIGITS IN MANY AREAS. THIS HIGH WILL MOVE SOUTH AND EAST MONDAY WITH A NEW LOW PRESSURE TROF DEVELOPING ACROSS THE NRN HIGH PLAINS. THIS TROF MOVES EAST TUESDAY WITH A WARMING TREND AND HIGHS IN THE 40S TO NEAR 50. .LONG TERM... WEDNESDAY THROUGH SATURDAY. AN UPPER LEVEL RIDGE OF HIGH PRESSURE WILL TRANSLATE EAST FROM THE ROCKIES INTO THE CENTRAL PLAINS DURING THE PERIOD. THIS WILL KEEP THE MILD AND MAINLY DRY WEATHER PATTERN IN PLACE. MODELS CONTINUE TO AGREE THAT THURSDAY WILL BE THE WARMEST DAY...AS 850 MB TEMPERATURES OF +15C COMBINE WITH A WESTERLY DOWNSLOPE WIND AND BRING POSSIBLE RECORD HIGHS /IN THE 60S/ TO PARTS OF THE AREA. MODELS AGREE THAT A COLD FRONT WILL BRING COOLER WEATHER TO THE AREA FRIDAY AND SATURDAY AS A TROUGH OF LOW PRESSURE DEVELOPS ACROSS THE WESTERN CONUS. && .AVIATION... PRECIPITATION IN THE FORM OF RAIN AND SNOW...WILL GRADUALLY END BY LATE AFTERNOON. THROUGH 23Z HOWEVER...VSBY MAY LOCALLY BE REDUCED TO 1/2 MILE AND IFR CONDITIONS IN HEAVIER SNOW ALONG A LINE FROM KAIA TO KOGA TO KLBF. OTHERWISE MOSTLY MVFR OR VFR EXPECTED. GUSTY NORTHWEST WINDS OF 25 TO 35 KTS CAN ALSO BE EXPECTED. RAPIDLY IMPROVING CONDITIONS SHOULD OCCUR THIS EVENING AS WINDS AND CLOUDS DECREASE. && .LBF WATCHES/WARNINGS/ADVISORIES...HIGH WIND WARNING UNTIL 9 PM CST /8 PM MST/ THIS EVENING FOR NEZ004-022-023-035-056>059-069>071. WIND ADVISORY UNTIL 9 PM CST /8 PM MST/ THIS EVENING FOR NEZ005>010-024>029-036>038-094. && $$ SHORT TERM...CDC AVIATION/EXTENDED...TAYLOR
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
335 PM CST SAT DEC 31 2011 .DISCUSSION.../ISSUED AT 335 PM CST/ LATEST RUC...NAM AND HRRR CONTINUE TO BE IN FAIRLY CLOSE AGREEMENT WITH PRECIPITATION DEVELOPING LATE THIS AFTERNOON AND EVENING... ESPECIALLY ALONG AND EAST OF INTERSTATE 29 ALONG AXIS OF STRONG H85 FRONTOGENESIS...WITH VERY LITTLE PRECIPITATION TO THE WEST. CURRENT RADAR STARTING TO SHOW PRECIPITATION DEVELOPING OVER SOUTHEAST SOUTH DAKOTA AHEAD OF SHORT WAVE AND WOULD EXPECT PRECIPITATION TO BECOME MORE WIDESPREAD. COLD FRONT ALREADY MOVING EAST OF I29 AND SHOULD MOVE THROUGH NORTHWEST IOWA AND SOUTHWEST MINNESOTA BY 01Z. LOOKS LIKE DYNAMIC COOLING OF THE LAYER SHOULD NOT BE A PROBLEM AND RAIN SHOULD CHANGE OVER TO SNOW FAIRLY QUICKLY AS UPPER WAVE APPROACHES. LIKE TO SEE A QUICK 2 TO 4 INCH SNOW OVER FAR EASTERN CWA WITH AN 1 TO 2 INCHES BETWEEN I29 AND THE HEAVIEST SNOW. ADD THE STRONG WINDS WITH THE SNOW AND WILL SEE SOME PRETTY BACK CONDITIONS FROM 00Z TO 06Z AND WILL KEEP WARNING GOING ACROSS THE FAR EAST WITH WINTER WEATHER ADVISORY CONTINUING JUST TO THE WEST. EVEN THROUGH SNOWFALL WILL NOT REACH WINTER STORMS CRITERIA...THE COMBINATION OF WIND AND SNOW...PLUS THE HOLIDAY EVE MAKES IT REASONABLE TO ISSUE SINCE THERE WILL BE PLENTY PEOPLE TRAVELING. SNOW SHOULD QUICKLY END AFTER 05Z OR 06Z AS SYSTEM PULLS AWAY. WILL ALSO KEEP THE WIND ADVISORIES GOING THROUGH SUNDAY WITH WIND GUST TO 35 TO 45 MPH TONIGHT AS SYSTEM GETS WOUND UP. WITH THESE CONTINUED STRONG WINDS SUNDAY WILL COME SOME LOW CLOUDS IN THE COOLER AIR...MAINLY TO THE NORTHEAST HALF OF THE FORECAST AREA. WHILE A FEW FLURRIES ARE NOT OUT OF THE QUESTION...HAVE ELECTED TO GO WITHOUT FOR NOW. UPPER SYSTEM WILL BE PULLING EAST STEADILY AND THE LOW CLOUD DECK IS EXPECTED TO GET PRETTY THIN. ANOTHER THOUGHT IS WILL THERE BE ANY LINGERING BLOWING SNOW IN THE FAR EAST AND HAVE LEFT THAT OUT AS WELL WITH MARGINAL ACCUMULATIONS AND AT LEAST 6 HOURS WITHOUT ANY FALLING SNOW BEFORE THE START OF THE DAY. CLEARING LOOKS STRONG FOR SUNDAY NIGHT. KEEPING WIND ADVISORY IS MARGINAL BUT AS EVENING WINDS SHOW A VERY SMALL DECREASE ON MODELS WILL KEEP AS IS FOR SOME MN AND IA COUNTIES THROUGH MIDNIGHT. COLDER...BUT YES STILL A LITTLE ABOVE NORMAL...TEMPERATURES SUNDAY WILL COOL MODESTLY SUNDAY NIGHT WITH THE SLOW WIND DECREASE. MONDAY SHOULD THEN BE FAIRLY SUNNY WITH SOME INCREASING HIGH THIN CLOUDS AND A TAD COOLER THAN SUNDAY ON HIGHS...BUT OF COURSE WITH MUCH LIGHTER WINDS AS SURFACE RIDGE MOVES OVER AREA. WARMING STARTS MONDAY NIGHT AND CONTINUES THROUGH PASSAGE OF WEAK TUESDAY SHORT WAVE WHICH WILL BRING ONLY SOME ASSOCIATED CLOUD COVER AND NO PRECIPITATION. WARMING WITH FAIRLY CLEAR SKIES WILL CONTINUE WEDNESDAY AND PEAK THURSDAY WITH A POTENTIAL FOR RECORD HIGH TEMPERATURES THURSDAY...AT LEAST HERE AT FSD WHERE WE HAVE OUR CURRENTLY LATEST SUB 50 DAILY RECORD HIGH FOR THAT DATE. FRIDAY AND SATURDAY LOOKS LIKE COOLING AND PROBABLY UNEVENTFUL...WITH LITTLE OR NO PRECIPITATION AND WINDS BEHIND FRIDAY COLD FRONT FOR NOW PROJECTED TO BE LESS THAN CURRENT SYSTEM. / WILLIAMS && .AVIATION.../FOR THE 18Z TAF ISSUANCE/ RAIN AND SNOW SHOULD DEVELOP ALONG THE INTERSTATE 29 CORRIDOR THIS AFTERNOON AND EXPAND ACROSS SOUTHWEST MINNESOTA AND NORTHWEST IOWA. CEILINGS AND VISIBILITIES WILL BECOME MVFR EAST OF I29 AND OCCASIONALLY LOWER TO IFR DUE TO SNOW. CEILINGS SHOULD BECOME VFR AFTER 06Z WITH VFR CONDITIONS EXPECTED WEST OF I29 THROUGH 18Z SUNDAY. STRONG NORTHWEST WINDS OF 25 TO 40 MPH...WITH GUSTS TO 50 MPH WILL SPREAD ACROSS THE REGION THIS AFTERNOON AND EVENING BEHIND COLD FRONT AND PERSIST THROUGH 18Z SUNDAY. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR IAZ001-012-020-031. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CSTTONIGHT FOR IAZ002-013-021-032. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY NIGHT FOR IAZ002-013-021-032. WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST TONIGHT FOR IAZ003-014-022. WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR IAZ003-014-022. MN...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR MNZ098. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR MNZ071-072-080-089. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY NIGHT FOR MNZ071-072-080-089-097. WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST TONIGHT FOR MNZ081-090. WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR MNZ081-090. NE...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR NEZ013-014. SD...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ038>040-052>056- 058>062-064>071. WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ050-057-063. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1120 AM CST SAT DEC 31 2011 .DISCUSSION.../ISSUED AT 1120 AM CST/ LATEST RUC...NAM AND HRRR MORE IN AGREEMENT WITH PRECIPITATION DEVELOPING DURING TEH AFTERNOON...ESPECIALLY ALONG AND EAST OF INTERSTATE 29 ALONG AXIS OF STRONG H85 FRONTALGENESIS...WITH VERY LITTLE PRECIPITATION TO THE WEST. CURRENT RADAR TRENDS SEEM TO VALIDATE THIS SCENARIO AND WILL TRIM BACK POPS WEST OF JAMES VALLEY AND INCREASE POPS ALONG I29 CORRIDOR FOR FSD-SUX WHERE POPS WERE ONLY AROUND 70%. SHOULD START AS RAIN AND THEN SWITCH TO SNOW BY LATE AFTERNOON AS LAYER COOLS DUE TO STRONG LIFT AND EVAPORATION. COULD SEE A QUIKC INCH OF SNOW ALONG I29 WITH 2 TO 4 INCHES FURTHER EAST. HAVE UPGRADED FSR EASTERN CWA TO WINTER STORMS WARNING FROM 00Z TO 06Z AND MAY NEED TO UPGRADE TO BLIZZARD WARNING WITH AFTERNOON FORECAST BASED ON TRENDS. && .AVIATION.../FOR THE 18Z TAF ISSUANCE/ RAIN AND SNOW SHOULD DEVELOP ALONG THE INTERSTATE 29 CORRIDOR THIS AFTERNOON AND EXPAND ACROSS SOUTHWEST MINNESOTA AND NORTHWEAST IOWA. CEILINGS AND VISIBLITIES WILL BECOME MVFR EAST OF I29 AND OCCASIONALLY LOWER TO IFR DUE TO SNOW. CEILINGS SHOULD BECOME VFR AFTER 06Z WITH VFR CONDITIONS EXPECTED WEST OF I29 THROUGH 18Z SUNDAY. STRONG NORTHWEST WINDS OF 25 TO 40 MPH...WITH GUSTS TO 50 MPH WILL SPREAD ACROSS THE REGION THIS AFTERNOON AND EVENING BEHIND COLD FRONT AND PERSIST THROUGH 18Z SUNDAY. && .PREVIOUS DISCUSSION.../ISSUED AT 400 AM CST/ MAIN FOCUS OF THIS PACKAGE IS THE POTENTIAL FOR SNOW AND WIND LATER TODAY AND TONIGHT...ESPECIALLY ACROSS SOUTHWEST MINNESOTA AND INTO NORTHWEST IOWA. AT 09Z...LOWS PRESSURE WAS LOCATED OVER SOUTHEAST MONTANA. THE STRENGTHENING GRADIENT HAS RESULTED IN INCREASING SOUTHEAST FLOW ACROSS MUCH OF THE AREA WITH TEMPERATURES REMAINING NEAR FREEZING. AS THE LOW RAPIDLY MOVES TO THE EAST...IT WILL DRAG A STRONG COLD FRONT ACROSS THE DAKOTAS AND NEBRASKA THIS MORNING...AND SOUTHWEST MINNESOTA AND NORTHWEST IOWA THIS AFTERNOON. BEHIND THE SURFACE FRONT...WINDS WILL RAPIDLY INCREASE WITH SUSTAINED WINDS LIKELY TO EXCEED 30 MPH BY LATE AFTERNOON...ESPECIALLY IN THE MISSOURI VALLEY. WOULD NOT BE SURPRISED IF SOME AREAS IN THE MISSOURI VALLEY SEE GUSTS TO 50 MPH LATE THIS AFTERNOON. STRONG 700 MB FRONTOGENESIS WILL FOLLOW THE PASSAGE OF THE SURFACE FRONT. ACCOMPANYING THIS AREA OF MID-LEVEL FRONTOGENESIS...A VERY STRONG PV ANOMALY WILL MOVE ACROSS THE DAKOTAS. A LINE OF LIGHT PRECIPITATION IS EXPECTED TO DEVELOP AS THE UPPER LEVEL ANOMALY INTERACTS WITH THE 700 MB FRONT. FOR NOW...EXPECTING THAT THIS PRECIPITATION WILL BEGIN AS RAIN IN THE JAMES AND MISSOURI VALLEYS AS WET BULB TEMPERATURE REMAIN BARELY ABOVE FREEZING. HOWEVER...IF COLDER AIR FOLLOWS MORE QUICKLY BEHIND THE SURFACE MAY SEE A MIX WITH SNOW EVEN AS FAR WEST AS HURON AND MITCHELL. PRECIPITATION AMOUNTS IN THE JAMES VALLEY ARE EXPECTED TO BE AROUND A TENTH OF AN INCH. AS PV ANOMALY MOVES INTO WRN IOWA...IT WILL CYCLONICALLY WRAP-UP. THIS WILL INTENSIFY THE 700 MB FRONT AS IT MOVES TOWARD I-29 AND EXPECTATION IS THAT THE PRECIPITATION BAND WILL BECOME MORE INTENSE AND ORGANIZED LATE THIS AFTERNOON AND THIS EVENING. IN ADDITION...WITH HIGHER PRECIPITATION RATES AND COLDER AIR WORKING IN...IT IS EXPECTED PRECIPITATION WILL BEGIN TO MIX WITH OR CHANGE TO SNOW TOWARD I-29 AND ESPECIALLY INTO SW MN AND NW IA AFTER 00Z. THERE IS EXPECTED TO BE AN AREA OF 1 TO 3 INCHES OF SNOW OVER MUCH OF SW MN AND ALONG HIGHWAY 71 IN NORTHWEST IOWA INCLUDING SPENCER AND STORM LAKE. WITH THE SNOWFALL...WILL BE SUSTAINED WINDS OVER 30 MPH WITH GUSTS APPROACHING 50 MPH. EVEN WITH NO SNOW CURRENTLY ON THE GROUND...THE COMBINATION OF FALLING AND ACCUMULATING SNOW WILL QUICKLY PRODUCE WIDESPREAD BLOWING SNOW...ESPECIALLY THIS EVENING...WHICH WILL REDUCE VISIBILITIES BELOW A HALF MILE. THEREFORE HAVE ISSUED A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW FROM 4 PM TO MIDNIGHT. EVEN WHERE NO ADVISORY IS IN EFFECT...SUCH AS AROUND SIOUX FALLS...CHEROKEE...AND SHELDON...BRIEF PERIODS OF LOW VISIBILITIES CAN BE EXPECTED WHEN SNOW IS FALLING LATE THIS AFTERNOON AND EARLY THIS EVENING. BECAUSE OF THE RAPID INTENSIFICATION OF THE UPPER LEVEL WAVE...CONFIDENCE IN THE EXACT AREA OF SNOWFALL REMAINS UNCERTAIN. THERE ARE TWO CONCERNS...FIRST PRECIPITATION SWITCHES MORE QUICKLY TO SNOW SO THAT SOME AREAS SEE IN EXCESS OF 3 INCHES OF SNOW...WHICH WOULD BE ENOUGH TO PRODUCE BLIZZARD CONDITIONS IN OPEN AREAS WITH THE EXPECTED WINDS. SECOND...HEAVIER SNOWFALL OF 1 TO 3 INCHES COULD EXTEND FARTHER WEST INCLUDING I-29 OR EVEN AS FAR WEST AS HIGHWAY 81 WHICH WOULD AFFECT YANKTON...BROOKINGS...SIOUX FALLS AND EVEN SIOUX CITY. PERSONS PLANNING TRAVEL LATER THIS AFTERNOON AND TONIGHT SHOULD MONITOR FORECASTS. AFTER THE SNOW ENDS...COULD SEE BLOWING SNOW THE REMAINDER OF THE NIGHT IN SW MN AND NW IA. OTHERWISE...WINDS OF 20 TO 40 MPH ARE EXPECTED. THIS WILL KEEP THE ATMOSPHERE WELL MIXED SO LOWS WILL REMAIN IN THE 20S. WINDY CONDITIONS WILL CONTINUE THROUGH SUNDAY WITH LITTLE WARMING. MOST PLACES WILL SEE HIGHS FROM THE MID 20S TO THE LOWER 30S. THE WINDS ARE EXPECTED TO REMAIN OVER 30 MPH IN SW MN AND NW IA INTO SUNDAY SO EXTENDED THE WIND ADVISORY INTO SUNDAY. WITH COLD AIR CONTINUING TO FILTER IN...LOWS WILL BE IN THE TEENS. MONDAY WILL SEE A RIDGE MOVE OVER THE AREA. WITH LIMITED MIXING AND SOME SNOW COVER EXPECTED IN OUR ERN CWA...HIGHS IN SW MN AND NW IOWA WILL STAY IN THE MID 20S. FARTHER WEST...WARM AIR WILL BEGIN TO MOVE IN AND TEMPERATURES WILL RISE INTO THE LOWER 30S. AS THE RIDGE MOVES OVER THE AREA MONDAY NIGHT...EXPECT SOME RADIATION COOLING...ESPECIALLY ALONG AND EAST OF I29 AND LOWER MINS TO AROUND 10 ABOVE. ALONG AND WEST OF THE JAMES RIVER...INCREASING SOUTH WINDS WILL KEEP LOWS IN THE TEENS. A WARMING TREND CAN BE EXPECTED FOR THE REMAINDER OF THE WEEK WITH NEAR RECORD TEMPERATURES POSSIBLE BY THURSDAY. NO PRECIPITATION IS EXPECTED. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR IAZ001-012-020-031. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR IAZ002-013-021-032. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY NIGHT FOR IAZ002-013-021-032. WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST TONIGHT FOR IAZ003-014-022. WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR IAZ003-014-022. MN...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR MNZ098. WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT CST TONIGHT FOR MNZ071-072-080-089. WIND ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST SUNDAY NIGHT FOR MNZ071-072-080-089-097. WINTER STORM WARNING FROM 6 PM THIS EVENING TO MIDNIGHT CST TONIGHT FOR MNZ081-090. WIND ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR MNZ081-090. NE...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR NEZ013-014. SD...WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ038>040-052>056- 058>062-064>071. WIND ADVISORY UNTIL 6 PM CST SUNDAY FOR SDZ050-057-063. && $$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1024 AM CST SAT DEC 31 2011 .UPDATE... A SHARP MOISTURE GRADIENT REMAINS ACROSS THE SOUTHEAST COUNTIES OF NORTH TEXAS THIS MORNING. THE PATCHY FOG THAT WAS PRESENT ACROSS THE SOUTHEAST EARLIER HAS DISSIPATED. LOW CLOUDS WILL REMAIN THROUGH THE MORNING BUT SHOULD BEGIN TO SCATTER OUT THIS AFTERNOON AS DRIER AIR MIXES DOWN. AN UNSEASONABLY WARM DAY IS SHAPING UP AROUND THE REGION WITH ABUNDANT SUN AND AN INCREASING SOUTH TO SOUTHWEST WIND. EXPECT AFTERNOON HIGHS IN THE LOWER AND MIDDLE 70S WITH A FEW UPPER 70S POSSIBLE ACROSS THE WEST. THE COLD FRONT THAT WILL MOVE THROUGH NORTH TEXAS TONIGHT IS CURRENTLY SWEEPING ACROSS THE HIGH PLAINS...BRINGING WITH IT MUCH COLDER TEMPERATURES AND STRONG NORTH TO NORTHWEST WINDS. THE FRONT WILL NOT HAVE THE SAME PUNCH WHEN IT MOVES ACROSS NORTH TEXAS TONIGHT BUT IT WILL CAUSE TEMPERATURES TO STEADILY FALL AND THE WINDS TO INCREASE AND BECOME GUSTY...ESPECIALLY FOR THE FIRST FEW POST-FRONTAL HOURS. THE ONLY CHANGES NECESSARY FOR THE UPDATE WILL BE TO REMOVE THE MENTION OF FOG FROM THE SOUTHEAST AND TO INCREASE WIND SPEEDS BEHIND THE FRONT TONIGHT. HOWEVER...WIND SPEEDS TONIGHT SHOULD NOT REACH WIND ADVISORY CRITERIA. 79 && .AVIATION... LOW CLOUDS/FOG PROGGED TO SHUNT NORTHEAST BEFORE IT REACHES WACO. LIFR/IFR CONDITIONS MAY PERSIST ALL DAY IN EASTERN NORTH TEXAS. HRRR SEEMS TO HAVE A GOOD HANDLE ON STRATUS AND WILL FOLLOW ITS GUIDANCE...SUPPORTED BY RUC SOUNDINGS AS WELL. COLD FRONT SHOULD REACH METROPLEX NEAR SUNDOWN...AND SHIFT WINDS BACK TO THE NORTH. LACK OF MOISTURE WILL PRODUCE CAVOK CONDITIONS WITH FROPA AND EXPECT CLEAR SKIES TO CONTINUE SUNDAY. 84 && .PREV DISCUSSION... /ISSUED 359 AM CST SAT DEC 31 2011/ LOW CLOUDS AND PATCHY FOG OVER SOUTHEAST TEXAS SHOULD SPREAD INTO THE SOUTHEASTERN PART OF NORTH TEXAS THIS MORNING. OTHERWISE...EXPECT A WARM AND MOSTLY SUNNY LAST DAY OF THE YEAR ACROSS NORTH TEXAS. AFTER MORNING LOWS IN THE 30S...TEMPERATURES WILL CLIMB INTO THE 70S AREA WIDE THIS AFTERNOON. A COLD FRONT THAT EXTENDED FROM CENTRAL SOUTH DAKOTA SOUTHWEST INTO THE NORTHERN COLORADO AT 3 AM... WILL SWEEP SOUTHEAST INTO THE WICHITA FALLS AREA BY SUNSET AND THROUGH ALL OF NORTH TEXAS BY THE TIME WE RING IN THE NEW YEAR. THIS FRONT WILL PROVIDE COOLER...BUT STILL DRY WEATHER...FOR A COUPLE OF DAYS. SOUTHERLY WINDS WILL RETURN LATE MONDAY NIGHT AND INCREASE SOME ON TUESDAY AHEAD OF THE NEXT SHORT WAVE AND COLD FRONT. THE INCREASING SOUTHERLY WINDS TUESDAY AND LOW RELATIVE HUMIDITIES WILL RESULT IN ELEVATED FIRE WEATHER CONDITIONS TUESDAY. THIS FRONT WILL THEN SWEEP THROUGH WEDNESDAY WITH NO PRECIPITATION EXPECTED ACROSS NORTH TEXAS. SOUTHERLY WINDS WILL RETURN BY LATE THURSDAY AND YET ANOTHER FRONT IS EXPECTED FRIDAY NIGHT/SATURDAY MORNING. AT THIS TIME IT LOOKS LIKE RAIN CHANCES WITH THE SYSTEM WILL LIKELY BE TO THE EAST OF THE FORECAST AREA. 58 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 73 38 60 34 56 / 5 0 0 0 0 WACO, TX 73 40 62 30 57 / 5 5 0 0 0 PARIS, TX 71 37 58 31 54 / 5 5 0 0 0 DENTON, TX 72 36 58 27 53 / 5 0 0 0 0 MCKINNEY, TX 72 37 60 30 55 / 5 0 0 0 0 DALLAS, TX 73 41 59 35 56 / 5 0 0 0 0 TERRELL, TX 71 40 59 32 57 / 5 5 0 0 0 CORSICANA, TX 72 40 62 33 57 / 5 5 0 0 0 TEMPLE, TX 73 37 61 30 57 / 5 5 0 0 0 MINERAL WELLS, TX 74 34 61 26 56 / 5 0 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 25/79
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 PM CST SAT DEC 31 2011 .SHORT TERM...TONIGHT THROUGH TUESDAY 315 PM CST SAT DEC 31 2011 MAIN FORECAST CONCERNS ARE HIGH WIND POTENTIAL TONIGHT THROUGH SUNDAY NIGHT AND WINTER WEATHER CONCERNS ON TOP OF THESE WINDS. CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED RIDGING BUILDING UP ALONG THE WEST COAST OF THE U.S. INTO BRITISH COLUMBIA...A SPLIT TROUGH OVER THE CENTRAL PORTION OF NORTH AMERICA...AND RIDGING OVER THE WESTERN GREAT LAKES AND OHIO VALLEY REGIONS. WITHIN THE SPLIT TROUGH...A VERY POTENT SHORTWAVE WAS NEAR GOODLAND KANSAS...AN UPPER LOW OVER SOUTHERN MANITOBA...AND A SHORTWAVE ON ITS BACK SIDE IN SOUTHERN ALBERTA. MUCH FOCUS IN ON THAT POTENT SHORTWAVE FOR THIS FORECAST. AT 12Z...WHEN IT WAS BACK NEAR RIVERTON WYOMING...THE SOUNDING SHOWED A DROP IN THE TROPOPAUSE OF 200MB AND A 500MB TEMP THAT COOLED 13C FROM THE PREVIOUS 00Z SOUNDING. MODELS HAVE STRUGGLED WITH THIS SHORTWAVE WITH ALL OF THEM NEEDING TO SHIFT MORE SOUTH AND DEEPER...ESPECIALLY THE NAM IN WHICH ITS 30.12Z RUN FORECASTED THE SHORTWAVE TO BE IN EASTERN SOUTH DAKOTA AT THIS TIME. AHEAD OF THE POTENT SHORTWAVE...A 995MB LOW WAS LOCATED OVER SOUTHEAST NEBRASKA. SOUTH WINDS OF 35 TO 50 KT WERE OCCURRING AT 925MB PER PROFILER DATA AHEAD OF THIS SURFACE LOW...ADVECTING WARMER AIR INTO THE FORECAST AREA. TEMPERATURES HAVE CLIMBED INTO THE 30S AND 40S...WARMEST IN NORTHEAST IOWA. ON THE BACK SIDE OF THE SURFACE LOW ACROSS WESTERN PORTIONS OF NEBRASKA... KANSAS AND ADJACENT STATES...SURFACE WINDS HAVE BEEN BLOWING HARD. PEAK GUSTS OF 40-50 KT AND EVEN A FEW UP AROUND 60 KT HAVE BEEN REPORTED. ALSO ON THE BACK SIDE OF THE LOW...PRECIPITATION HAS BEEN FORMING OVER NEBRASKA IN THE DEFORMATION AXIS. TONIGHT...FOCUS AGAIN IS MOSTLY ON THE POTENT SHORTWAVE. GOOD MODEL AGREEMENT EXISTS THAT THIS SHORTWAVE LIFTS RAPIDLY NORTHEAST INTO SOUTHERN LAKE MICHIGAN BY 12Z SUNDAY. THIS TRACK PLACES THE BEST 500MB HEIGHT FALLS TO OUR SOUTH...HOWEVER...PLENTY OF DPVA STILL OCCURS NORTH OF IT OVER THE FORECAST AREA. NEXT CONCERN IS THE DEFORMATION PRECIPITATION DEVELOPING OVER NEBRASKA. VERY GOOD AGREEMENT EXISTS THAT THIS PRECIPITATION WILL FORM INTO A SOUTHWEST-NORTHEAST BAND FROM WESTERN IOWA INTO NORTHWEST WISCONSIN THIS EVENING. IN FACT...THE BAND SHOULD INTENSIFY AS AN UPPER JET STREAK DEVELOPS OVER NORTHERN MINNESOTA...PLACING THE BAND IN THE FAVORABLE RIGHT ENTRANCE REGION. AS THIS JET CORE LIFTS INTO NORTHERN ONTARIO LATE IN THE EVENING THROUGH THE OVERNIGHT...THE DEFORMATION BAND OF PRECIPITATION LOOKS TO WEAKEN AS IT PUSHES EAST INTO THE FORECAST AREA. MEANWHILE...A NEW DEFORMATION BAND AIDED BY THE STRONGER 500MB HEIGHT FALLS IS FORECAST TO FORM FROM EASTERN IOWA INTO NORTHEAST WISCONSIN AFTER MIDNIGHT. BOTH BANDS CERTAINLY GIVE A GOOD OPPORTUNITY FOR PRECIPITATION...SO PRECIPITATION CHANCES ARE AT 100. HOWEVER...HAVE HAD TO DELAY SOME OF THE PRECIPITATION THIS EVENING BECAUSE OF THE FARTHER SOUTH TRACK WITH THE SHORTWAVE/SURFACE LOW. SNOWFALL AMOUNTS ARE TRICKY TOO. WITH A SLOWER MOVEMENT DUE TO THE SHORTWAVE BEING MORE AMPLIFIED...THE PRECIPITATION MAY END UP AS RAIN OR RAIN/SNOW MIX FOR A COUPLE HOURS. ONCE THE COLD AIR COMES IN...THERE MAY BE AN HOUR OF SOME HEAVIER SNOW...BUT THEN THE DEFORMATION BANDS PUSH EAST. COMBINE THAT WITH THE FACT THAT SNOW TO WATER RATIOS MAY ONLY END UP 10-15 TO 1...KEPT DOWN TOO AS A RESULT OF STRONGER WINDS DEVELOPING BREAKING THE SNOW CRYSTALS APART. HAVE REDUCED SNOWFALL AMOUNTS SOME TONIGHT...WITH NOW ONLY LESS THAN AN INCH SOUTH OF I-90 TO 1-2 INCHES ALONG AND NORTH OF THERE. NEXT CONCERN IS THE WINDS. AS THE SURFACE LOW ASSOCIATED WITH THE SHORTWAVE LIFTS INTO SOUTHEAST WISCONSIN AFTER MIDNIGHT...WINDS SHOULD KICK UP DRAMATICALLY IN ITS WAKE. A TIGHT PRESSURE GRADIENT...COLD AIR ADVECTION FOR MIXING... SUBSIDENCE AND RAPID PRESSURE RISES ARE ALL PRESENT...WHICH SHOULD ALLOW WINDS TO CRANK UP. WITH A 50-60KT CORE OF WINDS FORECAST BETWEEN 900-850MB...MUCH OF THIS SHOULD MIX DOWN. GREATEST POTENTIAL TO SEE HIGH WIND WARNING IS OVER NORTHEAST IOWA WHERE ISALLOBARIC FORCING IS MAXIMIZED. HAVE ISSUED THE WARNING IN THIS AREA. THE COMBINATION OF THE WINDS AND SNOW WILL RESULT IN SOME BLOWING SNOW...BUT THE EXTENT IS UNCERTAIN DUE TO AMOUNT OF SNOWFALL AND A WARMER GROUND FROM THE EVENING HOURS. BECAUSE OF THIS...DID NOT UPGRADE ANY WINTER WEATHER ADVISORIES TO WARNINGS. SUNDAY INTO SUNDAY NIGHT...POTENT SHORTWAVE IS PROGGED TO LIFT QUICKLY AWAY FROM THE AREA...WHILE THE SHORTWAVE OVER ALBERTA IS FORECAST TO SLIDE ACROSS WESTERN PORTIONS OF THE FORECAST AREA DURING THE DAY SUNDAY. INTERESTING FACT WITH THIS NEXT SHORTWAVE IS THAT THE TROPOPAUSE DROPS TO 600MB OR SO. WITH THIS SHORTWAVE COMING THROUGH...ALONG WITH THE SURFACE PRESSURE GRADIENT REMAINING TIGHT AND DURING PEAK HEATING...FELT IT WAS PRUDENT TO KEEP THE HIGH WIND WARNING GOING RIGHT THROUGH SUNDAY. ELSEWHERE...WIND ADVISORIES ARE STILL APPROPRIATE...AND KEPT THE WINTER WEATHER ADVISORY GOING FOR EASTERN PORTIONS OF THE FORECAST AREA UNTIL 15Z TO HANDLE ANY LINGERING DEFORMATION PRECIPITATION AS WELL AS BLOWING SNOW. BLOWING SNOW IS POSSIBLE ELSEWHERE...ESPECIALLY IN THE MORNING BEFORE SNOW PROBABLY BECOMES COMPACTED ENOUGH TO NOT RESTRICT VISIBILITIES AS MUCH. DID ALSO MAINTAIN 20-30 PERCENT CHANCES THROUGHOUT THE DAY SUNDAY FOR ISOLATED-SCATTERED SNOW SHOWERS...PRODUCED BY WEAK LIFT INDICATED IN THE LEFT-OVER STRATUS DECK BEHIND THE SYSTEM. DECIDED TOO TO HAVE A MENTION OF FLURRIES SUNDAY NIGHT WITH THE STRATUS DECK STILL AROUND...AS WELL AS NEUTRAL TO VERY WEAK LIFT IN THE CLOUDS. NOTE THAT MUCH OF SUNDAY NIGHT SHOULD END UP IN SUBSIDENCE WITH THE GENERAL UPPER TROUGH HEADING EAST. WITH COLD ADVECTION OCCURRING THROUGHOUT SUNDAY AND SUNDAY NIGHT...TEMPERATURES LOOK TO PRETTY MUCH HOLD STEADY OR SLIGHTLY FALL ON SUNDAY...FOLLOWED BY DROPPING INTO THE TEENS AND POSSIBLY SINGLE DIGITS FOR NORTH CENTRAL WISCONSIN. WINDS LOOK TO DIMINISH BELOW ADVISORY CRITERIA AROUND THE CURRENT END TIME IN THE FORECAST...06Z MONDAY...THOUGH IT IS POSSIBLE IT MAY NEED EXTENSION TO 12Z. WILL LET LATER SHIFTS TACKLE THIS MORE. MONDAY INTO MONDAY NIGHT...500MB HEIGHTS ARE FORECAST TO RISE QUITE A BIT DURING THIS TIME PERIOD...IN RESPONSE TO UPPER RIDGING BEING PUSHED EASTWARD INTO THE PLAINS. SUBSIDENCE ASSOCIATED WITH THE BUILDING HEIGHTS SHOULD RESULT IN A DRY FORECAST WITH GRADUAL CLEARING OF CLOUDS. WINDS LOOK TO ALSO GRADUAL DIMINISH...LIKELY GOING TO CALM MONDAY NIGHT WHEN THE SURFACE RIDGE MOVES THROUGH. DESPITE THE CLEARING OF CLOUDS...ANTICIPATING TEMPERATURES TO STILL STRUGGLE TO RISE MUCH...GIVEN 850MB TEMPS FORECAST BETWEEN -14 TO -18C MUCH OF THE DAY. GENERALLY FOLLOWED A BLEND OF GUIDANCE FOR HIGHS. COULD SEE SOME BELOW ZERO TEMPERATURES MONDAY NIGHT... ESPECIALLY IN THE TYPICAL COLD SPOTS OF WISCONSIN WITH SNOW LIKELY ON THE GROUND...COMBINED WITH THE CLEARING SKIES AND DIMINISHING WIND. IF THINGS SPEED UP A LITTLE MORE THAN WHAT IS FORECAST...A RISING TEMPERATURE TREND MAY NEED TO BE INCLUDED OVER WESTERN PORTIONS OF THE FORECAST AREA MONDAY NIGHT. TUESDAY...THE FEATURE MODELS HAVE PUSHING THE UPPER RIDGE EASTWARD INTO THE PLAINS IS A SHORTWAVE TROUGH...FORECAST OVER FAR EASTERN MONTANA AT 12Z TUESDAY. THIS TROUGH WILL HEAD EAST INTO MINNESOTA BY 00Z WEDNESDAY...INITIATING A WARM ADVECTION PATTERN OVER THE FORECAST AREA. AS A RESULT OF THIS WARM ADVECTION...LIKELY TO SEE DEVELOPMENT/TRANSLATION OF MID AND HIGH CLOUDS INTO THE FORECAST AREA. RAISED SKY COVER SOME...BUT MORE INCREASES MAY BE NECESSARY. PRECIPITATION IS NOT EXPECTED DUE TO DRIER LOW LEVEL AIR AND MUCH OF THE DPVA/THERMODYNAMIC FORCING PROGGED NORTHWEST OF THE FORECAST AREA. CERTAINLY SOMETHING TO WATCH. 850MB TEMPS DO CLIMB UP TO -4 TO -8C BY 00Z...SO HIGH TEMPERATURES SHOULD GET BACK UP INTO THE 20S FOR MOST LOCATIONS. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY 315 PM CST SAT DEC 31 2011 31.12 MODELS SHOWING A SHORTWAVE TROUGH MOVING ACROSS NORTHERN MINNESOTA AND INTO CENTRAL WISCONSIN TUESDAY NIGHT. THIS TROUGH HAS BEEN A FAIRLY CONSISTENT SIGNAL IN THE MODELS SO HAVE DECIDED TO EXPAND PRECIPITATION CHANCES FURTHER SOUTH...MAINLY TO ALONG THE I-94 CORRIDOR. TEMPERATURES WILL BE COLD ENOUGH TO ALLOW THE PRECIPITATION TO FALL AS SNOW. LOOK FOR LOW TEMPERATURES TO RANGE FROM THE MID TEENS ACROSS NORTH CENTRAL WISCONSIN TO AROUND 20 ACROSS NORTHEAST IOWA. A BROAD UPPER RIDGE IS EXPECTED TO SLIDE FROM THE NORTHERN PLAINS AND INTO THE UPPER MISSISSIPPI RIVER VALLEY WEDNESDAY INTO THURSDAY...WITH A GRADUAL WARMING TREND EXPECTED ACROSS THE FORECAST AREA. 850 MB TEMPERATURES WILL START OUT AROUND NEGATIVE 2 C EARLY WEDNESDAY AFTERNOON...WARMING TO AROUND PLUS 10 C BY THURSDAY AFTERNOON. HAVE NUDGED TEMPERATURES TOWARDS THE ECMWF WHICH SEEMS TO BE HANDLING TEMPERATURES BETTER OVERALL. QUIET WEATHER IS ANTICIPATED WEDNESDAY THROUGH THURSDAY WITH HIGH PRESSURE IN CONTROL. LOOK FOR HIGH TEMPERATURES MAINLY IN THE 30S ON WEDNESDAY...WARMING INTO THE 40S BY THURSDAY. FRIDAY COULD BE EVEN WARMER WITH TEMPS CLIMBING INTO THE UPPER 40S IN SOME LOCATIONS. HAVE INCREASED HIGH A COUPLE OF DEGREES ON FRIDAY...BUT IF TRENDS CONTINUE THEY WILL HAVE TO BE INCREASED FURTHER. THE RIDGE WILL PUSH EAST THROUGH THE DAY ON FRIDAY AS A COLD FRONT SWINGS SOUTH FROM CANADA AND THROUGH THE UPPER MIDWEST. THE OVERALL UPPER PATTERN LOOKS TO TRANSITION TO A NORTHWEST FLOW SCENARIO IN THE WAKE OF THE FRONT WITH A BROAD UPPER TROUGH SETTING UP ACROSS THE REGION. A SHORTWAVE TROUGH IS EXPECTED TO MOVE ACROSS THE REGION ON SATURDAY BRINGING A CHANCE OF LIGHT SNOW TO THE AREA. && .AVIATION...THROUGH 18Z SUNDAY 1207 AM CST SAT DEC 31 2011 A STRONG COLD FRONT WILL PUSH ACROSS THE AREA TONIGHT BRINGING STRONG NORTHWEST WINDS AND SNOW TO THE TAF SITES. PLAN ON IFR CONDITIONS THROUGH MUCH OF THIS AFTERNOON AS LOW LEVEL MOISTURE REMAINS IN PLACE. THE COLD FRONT IS EXPECTED TO MOVE ACROSS THE AREA LATE THIS EVENING. RAIN WILL DEVELOP FIRST...THEN SWITCHING OVER SNOW AS COLD AIR SWEEPS INTO THE REGION. WIND WILL QUICKLY INCREASE BEHIND THE FRONT INTO THE 25 TO 30 KT RANGE WITH GUSTS TO AROUND 47 KTS POSSIBLE...ESPECIALLY AT KRST. A PERIOD OF LIFR CONDITIONS ARE EXPECTED AS THE SNOW MOVES THROUGH. THE COMBINATION OF THE WIND AND SNOW WILL REDUCED VISIBILITIES TO AROUND 1 MILE OR POSSIBLY LESS AT TIMES. CONDITIONS WILL IMPROVE TO MVFR SUNDAY MORNING WITH BLOWING SNOW PERSISTING. PLAN ON VISIBILITIES IN THE 4 TO 5 SM RANGE. NORTHWEST WINDS WILL REMAIN IN THE 25 TO 30 KT RANGE WITH GUSTS UP TO 47 KTS POSSIBLE. && .ARX WATCHES/WARNINGS/ADVISORIES... 315 PM CST SAT DEC 31 2011 WI...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY FOR WIZ041-053>055-061. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 AM CST SUNDAY FOR WIZ032-033. WIND ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR WIZ032-033-041-053>055-061. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST SUNDAY FOR WIZ042>044. WIND ADVISORY FROM 9 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR WIZ017-029-034-042>044. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST SUNDAY FOR WIZ017-029-034. MN...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY FOR MNZ096. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 AM CST SUNDAY FOR MNZ079-086>088-094-095. WIND ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR MNZ079-086>088-094>096. IA...HIGH WIND WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT CST SUNDAY NIGHT FOR IAZ008-018-019-029-030. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY FOR IAZ010-011-019-029-030. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 6 AM CST SUNDAY FOR IAZ008-009-018. WIND ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR IAZ009>011. && $$ SHORT TERM...AJ LONG TERM...WETENKAMP AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
226 PM CST SAT DEC 31 2011 .SHORT TERM...TONIGHT THROUGH NEW YEARS DAY. LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A DEVELOPING LOW PRESSURE SYSTEM MOVING EAST OVER SOUTHEAST NEBRASKA THIS AFTERNOON...JUST AHEAD OF A VIGOROUS SHORTWAVE. WEAK SHORTWAVE IMPULSE TRAVELING NORTHEAST OVER MINNESOTA HAS GENERATED A BAND OF SLEET/FREEZING RAIN OVER NORTHERN WISCONSIN WHICH HAS BEEN REACHING THE GROUND...BUT IS NOT ACCUMULATING...ACCORDING TO A SPOTTER AT LAKE TOMAHAWK. OTHERWISE...MID AND HIGH CLOUDS CONTINUE TO PASS OVER THE STATE...AND LOW CLOUDS CONTINUE TO BE A NUISANCE OVER CENTRAL AND NORTHEAST WISCONSIN...JUST NORTH OF A SURFACE WARM FRONT. AHEAD OF THE LOW...PLENTY OF CLEAR SKIES AND DRY AIR EXISTS OVER KANSAS...MISSOURI...AND SOUTHERN ILLINOIS WHERE DEWPOINTS ARE IN THE 20S AND 30S. BUT FARTHER NW...AN FGEN BAND IS DEVELOPING OVER NE NEBRASKA AND SE SOUTH DAKOTA...WHICH WILL BE THE FEATURE TO WATCH HEADING INTO TONIGHT. ALSO...BEEFY WINDS OF 45-60 KTS ARE IMPACTING THE FRONT RANGE OF THE ROCKIES. AS THE SURFACE LOW TRACKS NE...HEADLINES FOR BOTH SNOW AND WIND ARE THE MAIN FORECAST CONCERNS. TONIGHT...BEEFY SHORTWAVE OVER THE PLAINS WILL BECOME NEGATIVELY TILTED AS IT DRIVES A SURFACE LOW TO THE NORTHEAST TO CENTRAL OR SOUTHERN LAKE MICHIGAN. MODELS DIDNT INITIALIZE ALL THAT WELL THIS MORNING (TOO WEAK WITH THE SHORTWAVE...AND THERMAL PROBLEMS)...SO ITS TOUGH TO HAVE CONFIDENCE IN ANY ONE PARTICULAR MODEL. TRIED TO BLEND THE NAM AND GFS...BUT CONFIDENCE IS NO BETTER THAN AVERAGE WITH THE DETAILS. ALTHOUGH WILL HAVE SE WINDS AT THE SURFACE...WINDS TURN TO THE SW ALOFT AND DRAW IN WARMER AIR FROM THE CENTRAL PLAINS. HOWEVER...THE AIR FROM THE PLAINS IS ALSO QUITE DRY AS DEPICTED BY THE 12Z RAOBS (PWATS LESS THAN 0.4 INCHES INTO NORTHERN TEXAS AND LOUISIANA)...AND PRECIP MAY BE SLOW TO MOVE INTO THE REGION DESPITE INCREASING FORCING. AS A RESULT...HAVE DELAYED PRECIP UNTIL AFTER MIDNIGHT. AS THE LOW MOVES OVER SOUTHEAST WISCONSIN TONIGHT...A TIGHTENING THERMAL GRADIENT ON THE NW FLANK OF THE LOW WILL LEAD TO AN FGEN CIRCULATION MOVING FROM SW TO NE ACROSS THE STATE. PTYPE IS LIKELY TO START OUT AS ALL SNOW OVER N-C WISCONSIN...WHERE EVAPORATION INTO A DRY LAYER ALOFT YIELDS WET BULB TEMPERATURES BELOW ZERO. NOT AS CLEAR CUT OVER CENTRAL WISCONSIN WHERE WET BULB TEMPERATURES APPROACH 0C AT MIDNIGHT SO LEFT A RAIN/SNOW MIX THERE. ENOUGH WARM AIR LOOKS TO SURGE INTO THE FOX VALLEY AND LAKESHORE WHERE PTYPE COULD START OUT AS ALL RAIN...BEFORE TRANSITIONING TO A MIX OR ALL SNOW BY 12Z. BECAUSE OF THE MIX...SNOW ACCUMS LOOK TO BE QUITE A BIT HIGHER OVER CENTRAL AND NORTH-CENTRAL WISCONSIN...ON THE ORDER OF 1 TO 3 INCHES...COMPARED TO LESS THAN AN INCH OVER THE FOX VALLEY AND LAKE SHORE. WINDS WILL ALSO BE BEGINNING TO STRENGTHEN LATE TONIGHT...BUT THE REAL PUSH WONT BE UNTIL SUNDAY MORNING. NEW YEARS DAY...LOW PRESSURE WILL CONTINUE TO STRENGTHEN AS IT LIFTS OVER NORTHERN LOWER MICHIGAN AND LAKE HURON ON SUNDAY. ONGOING PRECIP WILL HAVE CHANGED TO ALL SNOW EXCEPT OVER DOOR COUNTY EARLY SUNDAY MORNING. ARCTIC AIR WILL BE ROTATING AROUND THE LOW...WHICH WILL STEEPEN LOW LEVEL LAPSE RATES...AND ALLOW MIXING OF 900MB WINDS OF 40 TO 50 KTS. BECAUSE OF THE WINDS AND SNOWFALL...SUNDAY MORNING LOOKS TO HAVE THE MOST IMPACT FROM THE STORM...AS THERE COULD BE A 2-3 HR PERIOD OF FAIRLY NASTY CONDITIONS. THE SNOW WILL BE WINDING DOWN OVER CENTRAL AND NORTHEAST WISCONSIN POST 15Z WITH TOTAL ACCUMULATIONS OF 2-4 INCHES AND 1-3 INCHES RESPECTIVELY. HOWEVER...NW WINDS AND GROWING INSTABILITY OVER WESTERN LAKE SUPERIOR WILL SET UP GOOD CONDITIONS FOR LAKE EFFECT SNOW. SOME QUESTIONS ON THE EXACT WIND DIRECTION...AS 1000-850MB WINDS BACK AROUND TO THE 320-330 DEGREE DIRECTION LATE SUNDAY MORNING AND INTO THE AFTERNOON. AS A RESULT...BEST CONDITIONS FOR BEEFY SNOW ACCUMULATIONS MAY HAVE TO WAIT UNTIL SUNDAY NIGHT WITHIN THE SNOW BELT. WILL STILL KEEP 2-4 INCHES IN THE FORECAST THOUGH. ONCE THE SNOW DIMINISHES OUTSIDE THE SNOW BELT...WIND GUSTS WILL REMAIN AN ISSUE FOR THE REST OF THE DAY. GUSTS WILL LIKELY FALL IN THE 40-50 MPH RANGE...AND THE HIGHEST GUSTS SHOULD FALL OVER CENTRAL AND NORTHEAST WISCONSIN. HAVE POSTPONED THE START OF THE WIND ADVISORY UNTIL 18Z EVERYWHERE...FIGURING THE MORNING SNOW WILL HAVE POTENTIAL TO BLOW AROUND THROUGH AT LEAST MIDDAY. WILL SEE MORNING HIGHS IN THE MID 20S TO LOWER 30S FALL THROUGH THE DAY. AS FOR HEADLINES...ALREADY MENTIONED THE WIND ADVISORY. HAVE DELAYED THE WINTER HEADLINES UNTIL 06Z TONIGHT FOR NORTH-CENTRAL WISCONSIN AND UNTIL 09Z FOR NORTHEAST WISCONSIN (EXCEPT FOR THE DOOR WHICH STARTS AT 12Z). STUCK WITH THE WINTER WEATHER ADVISORY BECAUSE FIGURING SNOW AMOUNTS WILL BE IN THE 2-4 INCH RANGE AT THE HIGHEST END...AND THE SNOW WILL BE WINDING DOWN AS THE WINDS CRANK UP SUNDAY MORNING. THERE MAY BE A SHORT WINDOW OF A COUPLE HOURS OF LOW VSBYS (SAY A HALF MILE OR LESS)...BUT FELT THE MARGIN OF ERROR IS TOO HIGH FOR AN UPGRADE TO A WINTER STORM WARNING. COMBINED WITH UNCERTAINTY IN MODEL PERFORMANCE...HAVE STUCK WITH A WINTER WEATHER ADVISORY FOR NOW. .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY. CYCLONIC UPPER FLOW WILL PRODUCE LAKE EFFECT SNOW IN FAR NORTHCENTRAL WISCONSIN AND SNOW SHOWERS OR FLURRIES SUNDAY NIGHT THROUGH MONDAY. MONDAY SHOULD BE THE COLDEST DAY OF THE WINTER SO FAR WITH HIGHS IN THE HIGH SINGLE NUMBERS AND TEENS ALONG WITH A GUSTY WIND PRODUCING WIND CHILLS BELOW ZERO. 850 MB TEMPERATURES FORECAST TO FALL TO NEAR -20C LATE SUNDAY NIGHT AND MONDAY MORNING CREATING IMPRESSIVE INSTABILITY OVER LAKE SUPERIOR. WIND DIRECTIONS ARE NOT IDEAL (A LITTLE TOO MUCH WESTERLY COMPONENT) FOR VILAS COUNTY AND THE WIND SPEEDS ARE ACTUALLY STRONGER THAN IDEAL (WINDS MORE THAN 40 KNOTS DOES NOT PERMIT DRY AIR TO PICK UP MUCH MOISTURE IF IT TRAVEL SO FAST ACROSS THE LAKE). SO THINK THAT WE WILL SEE ANOTHER 3 TO 5 INCHES ACROSS VILAS COUNTY FOR THE SUNDAY EVENING THROUGH MONDAY NOON WITH LOCALLY HIGHER AMOUNTS NEAR THE MICHIGAN BORDER. UPPER RIDGING BEGINS TO ARRIVE MONDAY EVENING WHICH WILL CAUSE WINDS TO BACK SUFFICIENTLY TO DIMINISH THE LAKE EFFECT SNOW TO JUST FLURRIES. A CLIPPER SYSTEM WILL BRING INCREASING CLOUDS TUESDAY AND MAYBE SOME SNOW SHOWERS TUESDAY NIGHT. NO MUCH EXPECTED DUE TO VERY DRY AIR IN PLACE BEFORE IT/S ARRIVAL. THEN MORE UPPER RIDGING FOR WEDNESDAY NIGHT THROUGH FRIDAY WITH MAINLY DRY AND MILD WEATHER. A BIG DIFFERENCE IN THE MODELS FOR NEXT SATURDAY OVER THE WESTERN GREAT LAKES SO MADE NO CHANGES TO PREVIOUS FORECAST FOR THAT PERIOD. && .AVIATION...LOW CLOUDS ARE PUSHING NORTHEAST NORTH OF A WARM FRONT OVER THE NORTHERN MISSISSIPPI VALLEY. EXPECT THIS TO CONTINUE THIS AFTERNOON...THOUGH SOME BREAKS AND IMPROVING VISIBILITIES ARE POSSIBLE OVER THE FOX VALLEY. WENT OPTIMISTIC IN THIS REGARD...WHICH HAS SUPPORT FROM THE LATEST VISIBLE SATELLITE. A DYNAMIC LOW PRESSURE SYSTEM THEN WILL SWING NORTHEAST ACROSS THE PLAINS THIS EVENING...AND SOUTHERN WISCONSIN OVERNIGHT. PRECIP IS ANTICIPATED TO SPREAD FROM WEST TO EAST ACROSS THE TAF SITES STARTING AROUND MIDNIGHT OVER CENTRAL WISCONSIN. PRECIP TYPE SHOULD BE MOSTLY SNOW OVER NORTH-CENTRAL WISCONSIN WHERE TEMPS ALOFT ARE SLIGHTLY COOLER...BUT A MIX WILL LIKELY START THINGS OFF OVER THE FOX VALLEY. SNOW WILL CONTINUE THROUGH THE MORNING...WITH ACCUMS AROUND 2 INCHES OVER CENTRAL WISCONSIN AND THE FOX VALLEY...AND UP TO 4 INCHES AROUND RHI. STRONG SURFACE WINDS MAY BE A HAZARD SUNDAY AS DEEP LOW PRESSURE MOVES BY TO OUR SOUTH. SUSTAINED WEST TO NORTHWEST WINDS OF 25 TO 35 KNOTS WITH GUSTS TO 45 KNOTS POSSIBLE. MPC && .MARINE...SOUTH WINDS AHEAD OF AN APPROACHING ARCTIC FRONT COULD CAUSE HAZARDOUS CONDITIONS FOR SMALL CRAFTS THIS AFTERNOON AND TONIGHT. AS THE ARCTIC COLD FRONT SWEEPS EAST OF THE AREA LATE TONIGHT....WEST TO NORTHWEST GALES WILL DEVELOP SUNDAY MORNING WHICH WILL CONTINUE INTO MONDAY AFTERNOON. THERE IS AN OUTSIDE CHANCE THAT GUSTS COULD APPROACH OR REACH STORM FORCE OVER NORTHERN DOOR COUNTY SUNDAY NIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM 3 AM TO NOON CST SUNDAY FOR WIZ013- 020-021-031-037-038-045-048-073-074. WIND ADVISORY FROM NOON SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR WIZ010>013-018>021-030-031-035>040-045-048>050-073-074. WINTER WEATHER ADVISORY FROM 6 AM TO NOON CST SUNDAY FOR WIZ022- 039-040-049-050. WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST SUNDAY FOR WIZ010>012-018-019-030-035-036. WIND ADVISORY FROM NOON SUNDAY TO 6 PM CST MONDAY FOR WIZ022. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR WIZ005. && $$ MPC/MPC
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1050 AM CST SAT DEC 31 2011 .UPDATE... VISIBLE SATELLITE CLEARLY SHOWING WHERE DENSE FOG AND LIGHT FOG IS SET UP ACROSS SOUTH CENTRAL AND SOUTHEAST WI. EXTENDED THE DENSE FOG ADVY UNTIL NOON SINCE IT IS SLOW TO MIX OUT. NOT SURE IF IT IS VERIFYING IN JEFFERSON AND WALWORTH COUNTIES...BUT KEPT IT GOING. ALSO INCLUDED SHEBOYGAN COUNTY UNTIL NOON DUE TO DENSE FOG OVER THE EASTERN HALF OF THE COUNTY AND ALSO THE NEARSHORE MARINE ZONE. 12Z MODELS ARE COMING IN VERY STRONG WITH THIS SYSTEM FOR TONIGHT...STRONGER THAN PREVIOUS RUNS. VERY IMPRESSIVE PRESSURE RISE-FALL COUPLETS...STRONG Q-VECTOR CONVERGENCE...ETC. CURRENT WATER VAPOR IMAGERY SHOWING THE VERY STRONG SHORTWAVE DIGGING INTO WESTERN KANSAS WITH A NEUTRAL TILT DEVELOPING IN RUC 500MB HEIGHT FIELD. NEW NAM AND GFS AND CANADIAN MODELS ARE SHOWING MORE OF A NEGATIVE TILT IN THE 500MB HEIGHTS RIGHT OVER WI AT 12Z SUN. THEY ARE ALSO SHOWING TWO VORT MAXES COMING ACROSS...WITH THE FIRST ONE HITTING SOUTHERN WI AROUND 06Z AND THE SECONDARY ONE AROUND 18Z SUN. THE SECONDARY VORT MAX BRINGS WITH IT A VERY STRONG PV ANOMALY...WHICH COULD HAVE SOME IMPACT ON LINGERING SNOW SHOWERS AND STRONG WINDS. WE WILL BE CONSIDERING UPGRADING THE WINTER WEATHER ADVISORY TO HIGHER HEADLINES FOR SOME PORTIONS OF OUR FORECAST AREA. STAY TUNED. THIS IS A STRONG SYSTEM TONIGHT/SUN MORNING. VISIBILITIES MAY BE GREATLY REDUCED WITH THE BLOWING SNOW. ADDITIONALLY...ANY RAIN THAT FALLS WILL LIKELY FREEZE AS TEMPS FALL BELOW FREEZING OVERNIGHT AND SNOW WILL FALL ON TOP OF THE FROZEN SURFACES...CREATING HAZARDOUS CONDITIONS. && .AVIATION/18Z TAFS/...AREA OF STRATUS AND FREEZING FOG OVER SOUTH CENTRAL WI THIS MORNING WILL GRADUALLY MIX OUT BY NOON OR WORST CASE SCENARIO EARLY AFTERNOON. TAF SITES WILL EXPERIENCE VLIFR CONDITIONS WITHIN THE FOG AND STRATUS. MOSTLY VFR CONDITIONS WILL THEN RETURN LATER THIS AFTERNOON AND EVENING. LOW PRESSURE APPROACHING FROM IA WILL BRING LIGHT RAIN AND LIGHT SNOW TO THE REGION. THE LOW AND STRONG COLD FRONT WILL PASS ACROSS SRN WI SUNDAY MORNING WITH RAIN CHANGING TO SNOW AND STRONG WNW WINDS GUSTING TO 50 MPH OR HIGHER. IFR TO LIFR CONDITIONS WILL RETURN WITHIN THE STRONG WINDS AND SNOW THROUGH SUNDAY MORNING. THIS IS A STRONG SYSTEM TONIGHT/SUN MORNING. VISIBILITIES MAY BE GREATLY REDUCED WITH THE BLOWING SNOW. ADDITIONALLY...ANY RAIN THAT FALLS WILL LIKELY FREEZE AS TEMPS FALL BELOW FREEZING OVERNIGHT AND SNOW WILL FALL ON TOP OF THE FROZEN SURFACES...CREATING HAZARDOUS CONDITIONS. && .MARINE... A STRONG LOW PRESSURE SYSTEM WILL MOVE ACROSS LAKE MICHIGAN TONIGHT AND SUNDAY. WILL KEEP SMALL CRAFT ADVY FROM THIS EVENING THROUGH EARLY SUN MORNING FOR SOUTHERLY WINDS AHEAD OF THE SYSTEM...THEN EXPECTING A SHORT PERIOD OF RAMP-UP BETWEEN THE SMALL CRAFT TO GALE TO STORM SUN MORNING. UPGRADED THE GALE WARNING TO STORM WARNING FOR SUN MORNING THROUGH LATE SUN NIGHT. WESTERLY WINDS WITH THE COLD FRONT WILL HAVE QUITE A SURGE OF WINDS WITH THEM...THEN CONTINUE WITH STRONG SUSTAINED GALES WITH FREQUENT STORM GUSTS. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...FREEZING FOG ADVISORY UNTIL NOON CST TODAY FOR WIZ052-056-057- 062>064-067>070. WINTER WEATHER ADVISORY FROM 3 AM TO 9 AM CST SUNDAY FOR WIZ046- 047-056-057-062-063-067-068. WIND ADVISORY FROM 9 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR WIZ046-047-056-057-062-063-067-068. WIND ADVISORY FROM 6 AM SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR WIZ064>066-069>072. WINTER WEATHER ADVISORY FROM 6 AM TO NOON CST SUNDAY FOR WIZ051- 052-058>060. WIND ADVISORY FROM NOON SUNDAY TO MIDNIGHT CST SUNDAY NIGHT FOR WIZ051-052-058>060. LM...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR LMZ643>646. STORM WARNING FROM 6 AM SUNDAY TO 6 AM CST MONDAY FOR LMZ643>646. DENSE FOG ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR LMZ643. && $$ UPDATE...MRC