AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1010 PM EST MON MAR 5 2001 FCST CONCERN IS WHETHER BLSN ADVY CAN BE DROPPED. WV IMAGERY SHOWS UPPER LOW THAT HELPED PRODUCE IMPRESSIVE SNOW TOTALS OVER NCNTRL FA (15.6 INCHES HERE AT THE OFFICE TODAY) NOW MOVING ACROSS NE OH. ANOTHER SHORTWAVE IS SHEARING S FROM ONTARIO INTO WI ON NW SIDE OF BROADER UPPER LOW CIRCULATION. SOME ENHANCED CLOUDS ASSOCIATED WITH SHORTWAVE EARLIER HAVE NEARLY DISAPPEARED. SHSN HAVE DIMINISHED SIGNIFICANTLY OVER THE LAST FEW HRS AS SYNOPTIC LIFT HAS DEPARTED AND WEAK WAA OCCURS FROM THE N. ONE LAST PERSISTENT BAND OF HEAVIER SHSN CONTINUES TO MOVE ONSHORE NEAR MQT/ALGER COUNTY LINE. PER ETA/RUC...LK-850MB DELTA-T ONLY RUNNING ABOUT 13-14C CURRENTLY. WIND HAS DIMINISHED SOME THIS EVENING...BUT STILL GUSTY. WITH GUSTS ONLY OCCASIONALLY 20-25MPH NOW...BLSN IS NOT AS MUCH A FACTOR AS IT WAS EARLIER. WITH SHSN DIMINISHING...AMOUNT OF FRESH DRY SNOW TO BLOW ABOUT IS LESS NOW AS WELL. RUC/ETA SHOW 950MB WIND SPEEDS CURRENTLY 25-30KTS (IN GOOD AGREEMENT WITH LATEST KMQT 88D VWP) AND REMAINING IN THAT RANGE OVERNIGHT. SINCE BLSN HAS DIMINISHED AND WIND NOT TO INCREASE ANY OVERNIGHT...WILL DROP BLSN ADVY FOR ALGER/MQT. WILL CERTAINLY BE SOME BLSN IN OPEN AREAS AS CONFIRMED BY ALGER COUNTY SHERIFF...BUT IT WILL NOT BE WIDESPREAD OR PERSISTENT. AS FAR AS SNOW GOES...WEAK WAA OVERNIGHT WITH NO SYNOPTIC ENHANCEMENT WILL RESULT IN A CONTINUED DIMINISHING TREND OF THE LINGERING SHSN. INVERSIONS ALSO FALL TO AROUND 3KFT. WILL WORD AS LOCAL ADDITIONAL UP TO 2 INCHES NCNTRL WITH BETTER FETCH ACROSS LK AND UPSLOPE TO ASSIST. SOME CLEARING HAS OCCURRED OVER FAR W...BUT CLOUDS OVER WRN LK SUPERIOR ARE EXPANDING SOME. GOING FCST OF VARIABLE CLOUDS SHOULD COVER THE SITUATION AS THE W EDGE OF STRATOCU WILL BE BRUSHING THAT AREA. PLENTY OF CLOUDS/WEAK WAA AND WINDS REMAINING UP SUGGEST TEMPS WILL MOVE LITTLE FROM CURRENT READINGS. WILL GO WITH STEADY TEMPS NEAR CURRENT READINGS ALL AREAS. .MQT...NONE. ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 405 PM EST MON MAR 5 2001 12Z RAOBS/LATEST WV LOOP AND RUC ANAL SHOW VIGOROUS UPR LO OVR LWR MI UNDER BLOCKING UPR RDG IN NE CAN SINKING SLOWLY SWD. CORE OF COLD AIRMASS NR UPR LO WITH H5/H7/H85 TEMPS -35C/-27C/-19C. VERY STRG NLY FLOW OVR CWA (GUSTS AS HI AS 45 MPH) IN SHARP PRES GRADIENT BTWN 1035MB SFC HI OVR LK WINNIPEG AND 1006MB LO PRES OVR LK ONTARIO... WITH THE STRONGEST WNDS RPRTD IN EXPOSED LOCATIONS OF NCNTRL CWA. MQT VWP SHOWS 30-35KT WNDS WITHIN SVRL THOUSAND FEET OF SFC BLO INVRN HGT AT 6K FEET MSL. VSBY RESTRICTED MOST OF DAY AT SAW AOB 1/2SM WITH SHSN/BLSN. BUT TREND ON SN IS DCRSG AS DRY AIR IN ONTARIO WRAPPING INTO CYC CIRCULATION...WITH DIMINISHING AREA OF COLD CLD TOPS APRNT ON IR LOOP. PCPN HAS ALREADY BCM VERY LGT W OF MQT PER SFC OBS/88D REFLECTIVITY. WAD AT H85 ON N SIDE OF COLD AIR CORE TO THE S ALSO HELPING TO DIMINISH LES. H85 TEMPS AS FAR N AS CNTRL HUDSON BAY AS HI AS -1C AT 12Z...AND SFC TEMPS ON E SHORE OF JAMES BAY AS HI AS 32 THIS AFTN WITH SUNSHINE. ENHANCED CLDS OVR ONTARIO NOTED MOVG W ASSOCIATED WITH ANOTHER SHRTWV/JET MAX ROTATING ARND N SIDE OF CUTOFF TO THE S. SOME LGT SN OBSVD UNDER THIS CLD...BUT TREND ON CLD TOP TEMPS IS WRMG...IN GOOD AGREEMENT WITH MODEL FCST DIMINISHING H7-3 AND H85-5 QVECTOR CNVGC FIELDS. ALTHOUGH HARD TO PICK OUT ON 12Z RAOB ANAL...12Z AVN/ETA SUG A SUBTLE H85 THERMAL TROF ASSOCIATED WITH THIS SHRTWV. 18Z RUC PICKS UP ON THE THERMAL TROF AS WELL. MAIN FCST CONCERNS THIS PACKAGE ARE SN/BLSN/WND TRENDS AND GOING HEADLINES THIS EVNG...THEN CLD/TEMPS TUE/TUE NGT...THEN NXT SHRTWV WED INTO LATE WEEK. 12Z MODELS/18Z RUC SHOW UPR LO CONTG TO PRESS SEWD TOWARD MID ATLANTIC OVRNGT. JET MAX/SHRTWV ROTATING WWD THRU ONTARIO ATTM FCST TO DIG INTO BACK SIDE OF TROF AND MAINTAIN SHARPER PRES GRADIENT/NLY FLOW ACRS GRT LKS. BUT MODELS SHOW CONTG TREND OF DCRSG H7-3/H85-5 QVECTOR CNVGC AS SHRTWV GETS MORE SHEARED IN CONFLUENT UPR FLOW IN WRN LKS...SO NO UPR SUPPORT FOR LK ENHANCEMENT. ETA SHOWS 35KT WNDS AT 2K FEET MSL PERSISTING MOST OF EVNG AT MQT. SINCE SUBTLE H85 THERMAL TROF ASSOCIATED WITH DIGGING SHRTWV PASSES OVHD DURG NGT AND WL MAINTAIN AT LEAST A SIMILAR LLVL STABILITY PROFILE...HAVE OPTED TO GO WITH BLSN ADVY IN MQT/ALGER COUNTIES...THE ZNS MOST EXPOSED TO CONTD STRG NLY FLOW/LONGER FETCH ACRS LK TO SHARPEN LLVL INSTABILITY AND MIXING/AND PLACES THAT SAW THE MOST LGT/POWDERY SN TDAY. NO NEED FOR SN ADVY BECAUSE LK-H85 DELTA-T AT NO MORE THAN 13C AND INVRN HGT ARND 4K FEET NOT ENUF INSTABILITY FOR SGNT LES IN ABSENCE OF UPR DYNAMICS. BUT WL CONT TO CARRY UP TO 2 TO 3 INCHES IN PLACES OVR THE NCNTRL WHERE STRG UPSLOPE FLOW RESULTS IN SGNFT LLVL CNVGC. WNDS/ WAD/FLOW OFF LK SUP WL KEEP TEMPS NRLY STEADY PER MOS GUIDANCE AND FCST BLYR TEMPS. WEAKENING CYC FLOW EVIDENT TMRW AS UPR LO CONTS TO SLIDE OFF TO THE SE AND UPR HGTS RISE OVR THE NW GRT LKS. H85 TEMPS CONT TO WARM...UP TO -4C (W) TO -6C (E). SO ANY AM SHSN SHUD DIMINISH DURG AFTN. XPCT AT LEAST A LTL AFTN SUNSHINE OVR THE W AS ETA BUFKIT SHOWS INVRN HGT SUBSIDING TO 2K FEET AND AS FLOW BCMS SLGTLY ACYC DURG AFTN. DOWNSLOPING FLOW ACRS THE SE SHUD ALLOW SOME SUNSHINE THERE TOO. GIVEN MILD TEMPS OBSVD UPSTREAM...TENDED TOWARD HIER MAV GUIDANCE FOR MAX TEMPS. ALTHOUGH FLOW REMAINS MORE NNWLY TUE NGT...LWRG INVRN HGT TO 1K MSL (WRMG H925-H85 TEMPS) AND WEAKENING CYC FLOW SUG AT LEAST PARTIAL CLRG. TEMPS NR MOS GUIDANCE. PER PMDHMD...ETA HAS TRENDED TOWARD THE SHARPER AVN SOLN REGARDING THE NEXT POTENT SHRTWV PROGGED TO APRCH THE WRN LKS ON WED. GIVEN BLOCKING PATTERN IN PLACE...WL HEDGE TOWARD DEEPER AVN FCST. DESPITE ARRIVAL OF IMPRESSIVE H85-5 QVECTOR CNVGC AHD OF SHRTWV...DRY ATMOSPHERE IN ADVANCE OF THIS SYS WL LIMIT PCPN CHCS. BUT WL MAINTAIN CHCY POPS FOR W HALF OF CWA FOR NOW. EXTENDED MODELS SHOW BLOCKING UPR HI OVR NE CAN BRKG DOWN ONLY SLOWLY THIS WEEK WITH A TREND TOWARD SLOWER DEAMPLIFICATION...NOT SUPRISING CONSIDERING THE MODELS HAVE A TENDENCY TO BRK DOWN BLOCKS TOO QUICKLY AND DEEP LO DVLPG ON E CST THAT WL REINFORCE BLOCKING. PERSISTENCE OF UPR HI FORCES SHRTWVS THRU GLFAK TO BLD UPR RDG IN WRN CAN WITH A NWLY FLOW DVLPG IN CNTRL CAN/NRN PLAINS ON BACK SIDE OF MEAN ERN TROF HELD IN PLACE BY NE CAN HI. NXT POTENT SHRTWV TO DROP INTO WRN LKS ON WED-FRI. HAVE OPTED FOR SLOWER AND DEEPER SOLNS ON SPEED OF SYS GIVEN MODEL TRENDS AND ENSEMBLE FCSTS...SO WL KEEP GOING FCST FOR SHSN BOTH THU-FRI AND EVEN INTO EARLY SAT FOR ERN ZNS. ALTHOUGH FCST H85 TEMPS ON THE MARGINAL SIDE FOR LES...ASSUMING A DEEPER TROF/COLDER H85 TEMPS. MOST MODELS/ENSEMBLE MEMBERS SUG SHRTWV RDGING ON SAT INTO SUN... OPERATIONAL MRF/A FEW MRF ENSEMBLE MEMBERS/ECMWF OUTLIERS IN SHOWING SHRTWV APRCHG EARLY SUN. WL TREND TOWARD THE MAJORITY SLOWER SOLNS GIVEN BLOCKING PATTERN. IN THE LONGER TERM...MODELS/ENSEMBLES IN GOOD AGREEMENT SHOWING DEEP POLAR VORTEX JUST N OF HUDSON BAY WITH MEAN TROF INTO THE E PERSISTING INTO NXT WEEK BTWN UPR RDGING INTO NW CAN AND TOWARD GREENLAND. SUCH A PATTERN SUGS CONTD BLO NORMAL TEMPS WITH OPPORTUNITIES FOR SN AS SHRTWVS DIG SEWD THRU LKS INTO MEAN ERN TROF. COORDINATED WITH APX. .MQT...BLSN ADVY MIZ005-006 TNGT. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1200 PM EST MON MAR 5 2001 ONGOING LES AND BLOWING SNOW MAIN CONCERN FOR UPDATE. WV LOOP AND UPR AIR RUC ANALYSIS SHOWS DEEP CLOSED LOW OVER NRN LWR MI. PRONOUNCED LAKE TROF PERSISTS OVER AREA WITH IMPRESSIVE COLD AIR AND DEEP MSTR WRAPPING SSWD ON BACKSIDE OF LOW PER 12Z CWZC SNDG. TIGHT PRES GRAD ASSOC WITH LAKE TROF AND 2 MB 3HR PRES RISE MAX OVER CNTRL LAKE SUPERIOR GIVING RISE TO VERY STG WINDS THIS MORNING OVER MQT COUNTY...GUSTS TO 47 MPH AT BOTH NWS MQT AND KSAW DROPPING VSBYS DOWN TO NEAR ZERO AT TIMES IN SNOW AND BLOWING SNOW. COLDEST 850 MB AIR (-16C TO -18C) HAS ALREADY PASSED SOUTH OF LAKE SUPERIOR AND TEMPS THIS AFT ARE EXPECTED TO WARM FROM -15C TO -13C PER 12Z ETA MODEL DATA AS UPR LOW MOVES SE INTO WRN LAKE ERIE BY 00Z. ALTHOUGH...88D LOOP INDICATING 20-28 DBZ RETURNS NOT AS WIDESPREAD AS THEY WERE EARLIER THIS MORNING WITH HEART OF COLD AIR OVER LAKE...VWP STILL SHOWS GOOD FAIRLY UNIDIRECTIONAL 010-030 CBL FLOW THRU 14-15 KFT. ALSO EXPECT LES TO BE HELP ALONG BY DEEP MSTR AND GOOD CYCLONIC CONVERGENT FLOW THRU AFT. ALSO ENOUGH SPOTS OF 28+ DBZ OVER HIGHER TERRAIN OF MQT AND WRN ALGER TO KEEP LES WARNING GOING THERE THIS AFT...ESPECIALLY GIVEN BLOWING AND DRIFTING TO CONTINUE. WL GO 2-5 INCHES ADDITIONAL THIS AFT...STRESSING GREATEST AMTS AND BLOWING OVER HIGHER TERRAIN. FOR BARAGA-CMX-KEW VIS SATL SHOWS SOME DECENT LES BANDS WORKING OVER THESE COUNTIES WITH LWR VSBYS TO 1/2SM REPORTING AT CMX EARLIER WITH SHSN/BLSN AND WIND GUSTS TO 25 MPH OR MORE. ALTHOUGH AMS SOMEWHAT DRIER AIR AND DYNAMICS WKR FURTHER FM UPR LOW WL KEEP SNOW AND BLOWING SNOW HEADLINE GOING HERE BUT LIMIT FURTHER ACCUMS TO 1-3 INCHES. ALSO WENT 1-3 ADDITIONAL INCHES FOR SCHOOLCRAFT AND LUCE WHERE DESPITE GOOD INSTABILITY AND MSTR...SHORTER NNE FETCH WL BE LIMITING FACTOR. FURTHER SOUTH...LES BANDS TO PENETRATE INLAND WITH INCH OR LESS ACCUMS WITH BLOWING SNOW. FOR GOG-ONT COMBINATION OF EXTENSIVE LAKE ICE OVR WRN SUPERIOR AS WELL AS DRIER AIR...WKR NNE FLOW AND INVERSION HGTS BLO 4KFT HAVE CANCELLED SNOW AND BLOWING SNOW ADV THERE AND JUST MENTIONED LCL ACCUMS UP TO INCH. .MQT...LES WARNING THIS AFTERNOON MIZ005-006. LES AND BLSN ADVY THIS AFTERNOON MIZ001-003-004. GALE WARNING ERN LAKE SUPERIOR. VOSS mi SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 735 AM EST MON MAR 5 2001 AS PROMISED...NEW SET OF ZONES INDICATE LOWER AFTERNOON HIGHS. GIVEN THAT WE ARE STARTING OFF MUCH COOLER...UPR LOW IS SLOWLY MOVING SOUTH DRAGGING ITS COLD POOL ACROSS...WE SHOULD CLOUD OVER QUICKLY WITH -SHSN DEVELOPING. LATEST RUC APPEARS TO HAVE A GOOD HANDLE ON SHORT TERM EVENTS WITH POSITION OF INVERTED TROF OVER LAKE HURON AND 500MB LOW. LOW IS FORECAST TO BE NEAR MBS NEAR 18Z - PTK NEAR 19Z - DTW 20/21Z. KAPX 88D SHOWING THE FEATURE THAT IS STILL OF A CONCERN FOR TONIGHTS FORECAST. LAKE ENHANCEMENT (SOUTHEAST TO NORTHWEST ORIENTATION) AND ASSOCIATED SURFACE CONVERGENCE WILL BECOME MORE OF A PLAYER TONIGHT. THIS WILL BE WATCHED CLOSELY. .DTX...GALE WARNING FOR LAKE HURON TONIGHT. BGM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 1004 AM CST MON MAR 5 2001 MADE A QUICK UPDATE TO EXTREME SWRN ZONES OF MO AND SE KS DUE TO LOW CLOUDS MOVING INTO THIS AREA. ALSO KNOCKED TEMPS DOWN FROM UPPER 40S TO MID 40S IN SE KS DUE CLOUDS. RUC SHOWS A POCKET OF 70 PERCENT RH FOR THE REST OF TODAY OVER THIS AREA. EARLY MARCH SUN MIGHT HAVE A TOUGH TIME BURNING THESE CLOUDS OFF. ANYWAY WILL KEEP EYE ON SITUATION...MAY NEED ANOTHER UPDATE LATER. .SGF... .MO...NONE. .KS...NONE. SS mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA NE 255 PM CST MON MAR 5 2001 FORECAST CONCERNS AT FIRST CENTER ON CLOUDS AND TEMPERATURES...BUT LIGHT PRECIP MUST BE CONSIDERED BEGINNING TUESDAY NIGHT. CURRENTLY...AN ELONGATED RIDGE OF HI PRES EXTENDED SWD FROM MAN THRU ERN NEB INTO TX WITH A MINI HIGH OVER SD. A PERSISTENT BUT NARROWING BAND OF LOW CLOUDS LIES TO THE WEST OF THE RIDGE AXIS...WITH MORE SCT CLOUDS DIRECTLY UNDER THE RIDGE. TEMPS ARE MAINLY RUNNING A FEW DEG COLDER THAN SUNDAY. IN THE SHORT TERM...EXPECT STRATOCU FIELD TO REMAIN MAINLY TO OUR WEST TONIGHT. 18Z RUC AND MESOETA BOTH KEEP LOW LEVELS RELATIVELY DRY WITH A LIGHT ERLY COMPONENT TO THE WINDS FROM A MAINLY CLOUD FREE AREA. ON THE OTHER HAND...WITH GOOD RADIATION CONDITIONS...THIS WILL LIKELY RESULT IN PATCHY FOG BY MORNING AND PERHAPS SOME REDEVELOPMENT OF SC FIELD SIMILAR TO LAST NIGHT. SINCE I AM EXPECTING MOSTLY CLEAR SKIES WILL KEEP LOWS COLDER THAN LAST NIGHT...CLOSE TO PREVIOUS FCST AND NEW AVN MOS. ON TUESDAY...HIGH CLOUDS AND EVENTUALLY LOWER CLOUDS SHOULD BE INCREASING FROM THE WEST AS WEAK WAVE TUNNELS THROUGH UPPER RIDGE AND RETURN FLOW DRAWS LOW CLOUDS EASTWARD. THIS SHOULD KEEP A LID ON TEMPS AND EXPECT TO SEE LITTLE WARMING FROM TODAY. LIGHT SFC WINDS WILL ALSO SUPPRESS MIXING. MODELS BEGIN TO DIVERGE SLIGHTLY TUESDAY NIGHT WITH AVN PRODUCING SOMEWHAT MORE LIFT AND MOISTURE ACROSS SOUTH IN MID LEVELS...BUT STILL RATHER WEAK. EXPECT THE MAIN PRECIP THREAT TO BE FRZG DRZL ALREADY MENTIONED IN FORECAST FOR THE SOUTH. LOW LEVEL SATURATED LAYER GETS DEEP ENOUGH TO ALLOW DRIZZLE...BUT LIFT ALOFT IS PROBABLY INSUFFICIENT FOR MEASURABLE PRECIP. AFTER COORD WITH TOP...WILL MENTION DRZL ALONG WITH FREEZING DRZL... AS TEMPS MAY NOT BE BELOW FREEZING BEFORE PRECIP CHANCE. WE WERE IN AGREEMENT THAT ETA PROBABLY HAD BETTER HANDLING OF SOUTHERN BRANCH WED INTO WED NIGHT...WHICH WOULD TEND TO KEEP PRECIP FROM THAT SOURCE WELL TO OUR SOUTH. EXPECT CLOUDS TO RESULT IN RELATIVELY MILD TEMPS TUESDAY NIGHT... ABOVE NGM AND CLOSE TO AVN MOS. THE AIR BEHIND THE FIRST FRONT ON WEDNESDAY WILL NOT BE MUCH DIFFERENT FROM CURRENT AIRMASS. EXPECT A LITTLE SUN AND SLIGHTLY BETTER MIXING...WITH TEMPS RUNNING A FEW DEG ABOVE TUESDAY. AS IS OFTEN THE CASE...18Z MESOETA OFFERS A DIFFERENT SOLUTION...AS IT IS SLOWER WITH THE FRONTAL PASSAGE. THIS COULD ACTUALLY COOL TEMPS SLIGHTLY BY DELAYING THE CLEARING. WILL NOT GO WITH THIS SOLUTION YET. WED NIGHT EXPECT AT LEAST PARTIAL CLEARING. WINDS MAY KEEP MIN TEMPS UP A BIT...BUT WILL STILL GO FOR 10 TO 15 NORTH AND AROUND 20 SOUTH. FIRST PART OF EXTENDED WILL PROBABLY BE DRY BUT COLDER. NEXT VIGOROUS UPPER SYSTEM DROPPING OUT OF CANADA APPEARS FAR ENOUGH TO OUR EAST TO LEAVE US OUT OF THE PRECIP SHIELD...BUT CLOSE ENOUGH TO GIVE US MORE BACKDOOR COLD AIR. WILL KEEP FORECAST TEMPS BELOW GUIDANCE. FORECAST FROM SAT ONWARD IS QUITE UNCERTAIN. MRF HAS SUBSTANTIAL PRECIP FROM NEXT SW SYSTEM AS EARLY AS SATURDAY...BUT ECMWF WOULD HOLD OFF INDEFINITELY. TEMPS ARE LIKEWISE UP FOR GRABS. .OMA...NONE. POLLACK ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 905 PM EST MON MAR 5 2001 NO NEW MODEL DATA TO GO WITH YET THIS EVENING...BUT LATEST GOES IMAGERY AND REGIONAL RADAR MOSAIC INDICATING THINGS PRETTY MUCH GOING ACCORDING TO CURRENT FORECAST. RUC SHOWING GOOD DETAIL WITH REGARD TO UPPER SCALE FEATURES OFF SOUTHERN NEW ENGLAND COASTLINE. BACK EDGE OF SIGNIFICANT SNOW NOW EXTENDS FROM ROCHESTER TO ELMIRA TO SCRANTON AND SOUTHEASTWARD TO NEW YORK CITY AND NORTHERN NEW JERSEY... AND CONTINUES TO SLOWLY PIVOT SOUTHWESTWARD AS SHORTWAVE DUMBELLS AROUND DEEP UPPER LOW SHIFTING SOUTHWARD OVER OHIO THIS EVENING. MESOETA/RUC RH PROGS AND MESOETA QPF LOOK VERY REASONABLE IN EVENTUALLY SATURATING MUCH OF THE CURRENTLY DRY AREAS OVER THE WESTERN TWO THIRDS OF PENNSYLVANIA BY 12 UTC AND BACKING LIGHT SNOW SHOWERS IN FROM THE NORTHEAST WITH LIGHT ACCUMULATIONS OVER MOST AREAS EXCEPT THOSE COUNTIES CURRENTLY HIGHLIGHTED WITH ADVISORY OVER NORTHEAST SECTIONS. ALREADY AN INCH OR TWO IN SULLIVAN COUNTY REPORTED... BUT ECHOES HAVE TEMPORARILY DROPPED OFF IN INTENSITY. 3 TO 5 INCH RANGE IS STILL LOOKING GOOD HERE AS CURRENTLY FORECAST. OVER THE LAURELS WHERE WINTER STORM WARNING REMAINS IN EFFECT...EXPECT SNOW SHOWERS TO INCREASE OVERNIGHT AS UPPER LOW MOVES CLOSER AND STATIC STABILITIES CONTINUE TO LOWER. MODEL SOUNDINGS ARE IMPRESSIVELY MOIST THROUGH TUESDAY AND ALTHOUGH TRACK OF UPPER LOW IS NOT THE IDEAL SETUP FOR HEAVY SNOW IN THIS AREA...FEEL WINTER STORM WARNING IS WELL WARRANTED FOR SNOW TOTALS OF 3 TO 6 INCHES BUT MORE SIGNIFICANTLY EXPECT LOCAL BLIZZARD CONDITIONS TO BE DEVELOPING ON TUESDAY AS NORTHWEST WINDS INCREASE TO 25 TO 35 MPH WITH SIGNIFICANT BLOWING AND DRIFTING AND PLUNGING WIND CHILLS. WILL EMPHASIZE THESE HAZARDS IN UPDATED WSW STATEMENT TO BE ISSUED BY 10 PM. WORK ZONES BY 930 PM AS PHLWRKMIS. .CTP...WINTER WX ADV OVERNIGHT AND TUESDAY NORTHEAST CO.'S. WINTER STORM WARNING OVERNIGHT AND TUESDAY LAUREL HIGHLANDS DEVOIR pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 900 PM EST MON MAR 5 2001 -SN/-SHSN EVENT PROGRESSING AS FORECAST ALTHOUGH PRECIP DEVELOPED A LITTLE QUICKER THAN MENTIONED IN ZONES AND WILL HAVE TO CLEAN UP TIMING WORDING A BIT. 18Z MESOETA AND RUC STILL INDICATES VORT ENERGY ROTATING ARND ERN LAKES UPR LOW. INSTABILITY PRESENT WITH MESOETA SHOWING ARND 200 J/KG CAPE ACROSS ADVISORY REGION AND SHOWERY NATURE OF PRECIP EVIDENT FM AREA RADARS. CALLS TO MUCH OF THE AFFECTED REGION INDICATED MOSTLY FLURRIES WERE OCCURRING WITH NO ACCUMULATION IN VALLEY LOCATIONS. SMALL ACCUMULATIONS WERE REPORTED IN THE HIGHER TERRAIN THANKS TO OROGRAPHICS. BELIEVE THIS TREND WILL CONTINUE WITH ACCUMULATION ARND 1 INCH OR LESS IN THE SNOW ADVISORY AREA AND WILL LET ADVISORY RIDE. TEMPS GENERALLY LOOK GOOD BUT WILL OPEN UP RANGE A BIT FOR NRN CUMBERLAND PLATEAU COUNTIES WHERE LOWER MINS WILL OCCUR. .MRX... NC...NONE. TN...SNOW ADVISORY FOR MONDAY NIGHT FOR ZONES TNZ018...TNZ041... TNZ043...TNZ045...TNZ047...TNZ074. VA...SNOW ADVISORY FOR MONDAY NIGHT FOR ZONES VAZ001>002. tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 1000 AM CST MON MAR 5 2001 CURRENT ASOS/AWOS OBSERVATIONS AND REGIONAL SATELLITE IMAGERY SHOWING LOW LEVEL CLOUDINESS CONTINUING ACROSS THE NORTHEASTERN CUMBERLAND PLATEAU...WITH DECREASING CLOUDINESS S AND W. MSAS SFC ANALYSIS SHOWING TEMPS MAINLY IN THE LOW TO MID 30S...DEWPOINT DEPRESSIONS 5 TO 10 DEGREES...UNDER NWLY FLOW...WITH HIGH PRESSURE ACROSS E OK. 12Z KOHX SOUNDING PROFILE SHOWING STABLE ATMOSPHERIC CONDITIONS WITH MOISTURE LIMITED TO MAINLY THE BOUNDARY LAYER. UPPER AIR CHART DEPICTIONS SHOWING DRY NWLY FLOW CONTINUING ALOFT WITH MAIN AXIS OF TROUGH TO OUR EAST...AND PRONOUNCED RIDGING OVER THE W U.S. RUC MODEL SHOWING CONTINUANCE OF WEATHER PATTERN THROUGH THE AFTERNOON HOURS...WITH UPPER LEVEL LOW OVER LAKE MICHIGAN MOVING SE INTO LAKE ERIE AND DE-AMPLIFYING...AND SFC LOW MOVING SLOWLY NEWD OFF THE NEW ENGLAND COASTLINE. IN REFERENCE TO LOW CLOUD TRENDS...RUC MODEL SHOWING BEST MOISTURE FARTHER EAST THAN EARLIER EXPECTED THROUGH 00Z TUE...IN ASSOCIATION WITH WRAP AROUND MOISTURE OF LOW OFF THE NEW ENGLAND COAST. THIS SCENARIO ALSO IN AGREEMENT WITH CURRENT SATELLITE IMAGERY TRENDS. WILL ADDRESS SKY CONDITION TRENDS AS MOSTLY SUNNY W HALF WITH PARTLY SUNNY SE TO MOSTLY CLOUDY NE PLATEAU. WILL ALSO ELIMINATE WORDING FOR FLURRIES AS NO REPORTS RECEIVED THIS MORNING. AS FOR TEMPS...KOHX SOUNDING FORECAST MAX TEMP 43 DEGREES. VALUE ALSO IN LINE WITH LAMP DATA AND NEW NGM MOS. TEMPS ACROSS E PORTIONS OF REGION STILL IN LINE WITH FORECASTED HIGHS. WILL UPDATE TEMPS ACROSS ALL REGIONS BY ONE CATEGORY...EXCEPT NE PLATEAU. .BNA...NONE. 14 JBW tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 430 AM EST TUE MAR 6 2001 MAIN FCST CONCERNS THIS PACKAGE SHIFT FROM CLOUDS/TEMPS TODAY/TONIGHT TO SNOW CHANCES WED NIGHT INTO THURSDAY. WV IMAGERY AND RUC ANALYSIS INDICATED CLOSED LO OVER NRN VA BENEATH BLOCKING RDG OVER CNTRL/NE CANADA. WRN LK SUPERIOR WAS UNDER INFLUENCE OF MID/UPR LVL CONFLUENCE BETWEEN THESE FEATURES WITH STRONG DRYING EVIDENT. UPR LVL CONVERGENCE AND ASSOCIATED H7-H3 QVECTOR DIV AND SUBSIDENCE HAD BROUGHT CLEARING TO FAR WRN UPR MI. OVER THE REST OF UPR MI...WEAK CYCLONIC FLOW AND MOISTURE ADVECTION AROUND BACK SIDE OF DEEP LO CIRCULATION WERE KEEPING CLOUDS IN PLACE. LK-H8 DLT/T TO AROUND -13C WAS ALSO PROVIDING ENOUGH INSTABILITY FOR ADDITIONAL MOISTURE/CLOUDS FROM LK SUPERIOR. HOWEVER...KMQT 88D AND SFC OBS INDICATE LES HAD DWINDLED TO MAINLY FLURRIES WITH MORE CELLULAR APPEARANCE OF RETURNS. IR LOOP AND SFC OBS SHOWED ADDITIONAL MOISTURE WORKING WESTWARD THROUGH ERN ONTARIO TOWARD ERN LK SUPERIOR WITH 3SM -SN AND FZDZ AT CYTS AND CYSB. TODAY...06Z ETA AND RUC SUGGEST WEAK SHRTWV ENERGY...MOISTURE AND LIFT FROM THE NORTHEAST WILL BE SHUNTED SOUTHWARD AND SHEARED OUT BY CONFLUENT ZONE. SO...ANY EFFECTS WILL BE CONFINED TO ERN CWA WITH MORE PERSISTENT CLOUDS/FLURRIES. REST OF UPR MI SHOULD SEE GRADUAL DECREASE IN CLOUDS FROM THE WEST AND THINNING CLOUD DECK AS DRYING ALOFT IS AIDED BY DIURNAL LLVL MIXING WITH MARCH SUN. H9 TEMPS TO NEAR -8C...SUPPORT TEMPS IN CURRENT FCST RANGE OF 25 TO 30 WITH BKN CLDS. WITH ENOUGH SUN...EXPECT 30-35 TEMPS...PARTICULARLY SOUTH AND WEST. TONIGHT...WEAK RDGING WITH LLVL ACYC FLOW AND WEAK DRY ADVECTION SHOULD BRING ADDITIONAL CLEARING. LOW TEMPS NEAR GUIDANCE LOOK ON TRACK WITH GOOD RADIATIONAL COOLING CONDITIONS CNTRL AND WEST PORTIONS. WEDNESDAY AND WED NIGHT...ETA/AVN IN REASONABLE AGREEMENT WITH TIMING AND PLACEMENT OF H5 SHRTWV AND DEVELOPING CLOSED LO. TREND HAS BEEN TOWARD A SLIGHTLY DEEPER SOLN WITH SYSTEM CLOSING OFF EARLIER WITH SLIGHTLY STRONGER H7-H3 QVECTOR CONVERGENCE. ACCORDINGLY...WL BOOST POPS SLIGHTLY FROM GUIDANCE AND PREVIOUS FCST EVEN THOUGH INCREASED FORCING IS WORKING WITH RELATIVELY DRY AIRMASS. ENOUGH OPEN WATER REMAINS OVER WRN LK WITH LK-H8 DLT/T TO AROUND 11C WL TO BRING POSSIBILITY FOR LK ENHANCEMENT OVER WEST WITH NW FLOW AS DEEPER MOISTURE ARRIVES WED EVENING. .MQT...NONE. JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 930 AM CST TUE MAR 6 2001 FORECAST HIGHS TODAY VERY SIMILAR TO MONDAY VERIFICATION TEMPS. TEMPS AND DEWPOINTS IN LINE WITH THOSE THIS TIME YESTERDAY. NUTREAL TEMP ADVECTION BASICALLY OFFSET BY ADVANCE OF SOME HIGH LEVEL CLOUDINESS ACROSS AREA. THUS...A 15 DEGREE OR SO RISE FROM 9 AM TEMPS APPEARS IN ORDER...YIELDING HIGHS RANGING IN 60S. RUC INDICATES HIGH CLOUDS TO BE TRANSIENT...WITH SKIES ONCE AGAIN CLEARING TONIGHT. NO CHANGES TO FORECAST NEEDED. VII .SHV...NONE. la AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE MARQUETTE MI 1100 AM EST TUE MAR 6 2001 MAIN CONCERN FOR TDA IS AMNT OF SUNSHINE AND HI TEMPS. WV IMAGERY AND RUC ANLYS SHOWING A DEEP ULVL LOW DIVING THRU THE SRN NEW ENGLAND STATES. A SERIES OF SHRTWV WERE CYCLING ARND THIS LOW WITH ONE OVR THE CWA THIS AM. A SFC RIDGE WAS MOVING STEADILY ACRS THE NRN PLAINS INTO THE FA. RUC 290K ISENTROPIC ANLYS INDICATING LLVL LIFT OVR FA THIS AM. THESE WERE PRODUCING THE LOW CLDS XPERIENCED ACRS THE CWA THIS AM. MORNING RAOBS FM UPSTREAM STATION CWPL SHOWING SATURATED BLO H90 AND DRY ABV. SFC REPORTS AND VIS IMAGERY SHOWING SKC OVR WI AND MN ATTM. MESO-ETA/RUC HAS H85-H50 Q-VEC DVRGNC SPREADING ACRS CWA THIS AFTN. 290K ISENTROPIC ANLYS SUPPORT SUBSIDENCE ACRS FA THIS AS WELL THIS AFTN. AS THE UPR LOW SLIDES INTO THE ATL THIS AFTN...XPCT THIS DRYER AIR OVR WI TO ADVECT OVR FA FM W THIS AFTN. WILL KEEP CLDS IN EARLY....BUT XPCT A FEW BREAKS BY LATE AFTN. FLOW AHEAD OF SFC RIDGE WILL KEEP WINDS OUT OF THE NW THIS AFTN. Q-VEC DVRGNC SLIDE ACRS FA THIS EVENING. BY LATE TNGT...CONVERGENCE WILL INCREASE. MEAN 1000-850 RH WILL INCREASE FM THE W AS WELL. THE NXT SHRTWV WILL SHIFT INTO WRN UP OVRNGT. LOOKING FOR INCREASE CLD CVR OVRNGT...WHILE WINDS DROP OFF. A WEAK ASSOC SFC TROF WILL REACH INTO THE WRN LAKKES BY 12Z WED. 1000-850MB MEAN RH WILL INCREASING TO 80+ PCT. THUS CHC OF SNOW POSSIBLE OVR THE W IN THE AM...AND SPREAD ACRS DURING THE DAY WED. .MQT...NONE. DLG mi AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE MARQUETTE MI 545 AM EST TUE MAR 6 2001 KMQT 88D INDICATED RAPID DECREASE IN REFLECTIVITIES BTWN 0900Z-1030Z. -FZDZ HAS DEVELOPED AS AVBLTY OF ICE NUCLEI DWINDLES WITH DRYING ABV INVERSION AND 900-850 MB TEMP CLIMBING AOA -10C...PER 09Z RUC. AREAS MOST AFFECTED WL BE AREAS ADJACENT TO LK SUPERIOR INFLUENCED BY ADVECTION OF MARINE LYR WITH NRLY FLOW...PARTICULARLY LOCATIONS WITH SIGNIFICANT UPSLOPE. SO...HAVE ADDED MENTION OF PATCHY -FZDZ FOR THIS MORNING FOR KEWEENAW EASTWARD. .MQT...NONE. JLB mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE COLUMBIA SC 1010 AM EST TUE MAR 6 2001 UPDATE TO DROP WIND ADVISORY AND JUST GO WITH WIND ADVISORY ON THE AREA LAKES. UPPER LOW HAS MOVED FATHER SOUTH THAN EXPECTED. NOW NEAR ORF. IT WILL BRING WRAP AROUND MOISTURE INTO VIRGINIA AND NORTH CAROLINA WITH SOME REACHING SOUTH CAROLINA BEFORE BREAKING UP. RUC H8 TEMPERATURES -10/-11 THIS MORNING. SO COLD AIR CONTINUES TO POUR INTO THE CAE CWA. VISIBLE SATELLITE INDICATES A LOT OF STRATOCU DEVELOPING ACROSS NORTH CAROLINA AND MAY GIVE GOOD COVERAGE TO NORTHERN PART OF CAE CAW. RUC TIME HEIGHTS NORTH OF CAE SHOW THIS TO BE THE CASE. CAE 88D INDICATED MAYBE SOME FLURRIES NORTH PART EARLIER BUT NOTHING NOW AND DON'T EXPECT ANY FLURRIES. BUT WILL UPDATE FOR SKY CONDITIONS. MOSTLY CLOUDY NORTH AND PARTLY CLOUDY REST OF AREA. WILL LOWER HIGHS TO NEAR 40 NORTH PARTLY AND LOWER TO MID 40S SHOULD BE GOOD FOR REST OF AREA. WILL SAY 42 TO 46 CAE-AGS-OGB. FCSTID = 7 CAE 43 30 55 28 / 10 10 10 10 AGS 46 28 57 27 / 10 10 10 10 SSC 42 30 54 28 / 10 10 10 10 OGB 45 30 56 28 / 10 10 10 10 .CAE... WIND ADV FOR TODAY....DROP ADVY FO CWA. FREEZE WARNING FOR TONIGHT.....CWA. RED FLAG WARNING FOR TODAY.....CWA. TTH sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 955 AM EST TUE MAR 6 2001 UPPER LOW HAS MOVED FATHER SOUTH THAN EXPECTED. NOW NEAR ORF. IT WILL BRING WRAP AROUND MOISTURE INTO VIRGINIA AND NORTH CAROLINA WITH SOME REACHING SOUTH CAROLINA BEFORE BREAKING UP. RUC H8 TEMPERATURES -10/-11 THIS MORNING. SO COLD AIR CONTINUES TO POUR INTO THE CAE CWA. VISIBLE SATELLITE INDICATES A LOT OF STRATOCU DEVELOPING ACROSS NORTH CAROLINA AND MAY GIVE GOOD COVERAGE TO NORTHERN PART OF CAE CAW. RUC TIME HEIGHTS NORTH OF CAE SHOW THIS TO BE THE CASE. CAE 88D INDICATED MAYBE SOME FLURRIES NORTH PART EARLIER BUT NOTHING NOW AND DON'T EXPECT ANY FLURRIES. BUT WILL UPDATE FOR SKY CONDITIONS. MOSTLY CLOUDY NORTH AND PARTLY CLOUDY REST OF AREA. WILL LOWER HIGHS TO NEAR 40 NORTH PARTLY AND LOWER TO MID 40S SHOULD BE GOOD FOR REST OF AREA. WILL SAY 42 TO 46 CAE-AGS-OGB. FCSTID = 7 CAE 43 30 55 28 / 10 10 10 10 AGS 46 28 57 27 / 10 10 10 10 SSC 42 30 54 28 / 10 10 10 10 OGB 45 30 56 28 / 10 10 10 10 .CAE... WIND ADV FOR TODAY....CWA. FREEZE WARNING FOR TONIGHT.....CWA. RED FLAG WARNING FOR TODAY.....CWA. TTH sc AREA FORECAST DISCUSSION...CORRECTION NATIONAL WEATHER SERVICE WAKEFIELD, VA 1028 AM EST TUE MAR 6 2001 SHUD FRAME H5 CHART THIS MORNING...NOT TOO MANY TIMES HAS THE POLAR VORTEX PLUNGED TO THE MOUTH OF THE CHES BAY. ANYWAY...WAA FM THE NE (DEPICTED @ H85) ARND STM CIRCULATING INVOF SRN NEW ENGLAND...RESULTING IN DECENT BAND OF SN ROTATING SWWD INTO PORTIONS OF CNTRL DELMARVA ATTM. SN HAS BEEN GENLY LGT...AMS DRY...BUT GIVEN TEMPS WL STAY AOB FRZG THRUT DAY...SHUD BE EASY TO ACCUMULATE A CPL INCHES...SO HV DECIDED (AFT COORD WITH PHL) TO RAISE WINTER WX ADVSRY FOR THOSE LCTNS (GENLY 1 TO 2 IN...AND WE'LL SEE IF THAT HOLDS IT). THE SN BAND XTNDS NNE TO LI...BUT LIKELY TO WKN NEXT 12 HRS (LATEST RUC SUGGS THAT TREND) AS LO BEGINS TO GRDLY PULL AWAY FM CST AND LLVL WAA SLOLY SUBSIDES. KEPT UP WND ADVSRY...STILL WORRIED ABT SURGE THIS AFTN/ERY EVE. DECENT SFC PRES RISES ABT TO CRS THE MTNS...AND FLO THRUT DEEP LYR ALIGNING STRNGLY FM NW SHUD BE ENUF TO PUSH WNDS ALOFT TO SFC. WND SPDS AT 12Z ARND 2-3KFT AVGG 40 KTS...AND XPCTG THOSE SPDS (AT LEAST IN GUSTS) THIS AFTN. WRT PCPN...AGAIN BEST/HIEST CHCS ON ERN SHR...TO CHC POPS ALL OTR SPOTS. MAY GET A BAY PLUME LTR TDA/TNGT IF LLVL FLO CAN TURN MR NNWLY FOR A TM (H85 TEMP TO WTR TEMP DIFF CERTAINLY FITS CRITERIA). SLO IMPRVMNT WED INTO THU. FCSTID = 25 .AKQ... MD...WIND ADVISORY FOR TUESDAY FOR ZONES MDZ021>025. WINTER WEATHER ADVISORY FOR THIS AFTERNOON AND EARLY EVENING FOR ZONES MDZ021>025. GLW ATLC CSTL WTRS FENWICK ISL TO CHINCOTEAGUE. NC...WIND ADVISORY FOR THIS AFTERNOON FOR ZONES NCZ012>015...NCZ030>032. WIND ADVISORY FOR THIS AFTERNOON AND EARLY TONIGHT FOR ZONES NCZ016>017...NCZ102. GLW ATLC CSTL WTRS NC/VA BRDR TO CURRITUCK BCH LGT...AND SND. VA...WIND ADVISORY FOR THIS AFTERNOON FOR ZONES VAZ048>049...VAZ060>094...VAZ096. WIND ADVISORY FOR THIS AFTERNOON AND EARLY TONIGHT FOR ZONES VAZ095...VAZ097>100. WINTER WEATHER ADVISORY FOR THIS AFTERNOON AND EARLY EVENING FOR ZONES VAZ099>100. GLW VA PTRN CHES BAY...AND ATLC CSTL WTRS CHINCOTEAGUE TO NC/VA BRDR. va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 230 PM EST TUE MAR 6 2001 CLD CVR/RESULTANT TEMPS THE MAIN CONCERN THROUGH THE PD AS MOS NUMBERS ARE QUITE DIFFERENT AT TIMES THROUGH THE FCST CYCLE. SFC/UA ANLYS CONT TO SHOW THE STG LOW PRES SYS SPINNING JUST OFF THE ATLTANTIC COAST WITH A SFC HIGH PRES RIDGE ACRS THE PLAINS AND NW FLOW ALOFT ACRS THE FA. SAT PIX SHOWING CU FIELD ROUGHLY NE OF A SEYMOUR TO TERRE HAUTE LINE. THIS FIELD IS SHRINKING SOME BUT DAYTIME CU FORMING ON THE PERIPHERY. MODELS AGREE ON PUSHING THE STG LOW PRES AREA FURTHER OUT TO SEA AND BRINGING AN UPR LOW FM SCNTRL CANADA ACRS THE GT LKS WED NGT-THU NGT. THEY ALSO SWING A WEAK CD FNT ACRS WED NGT. PREFER ETA/AVN COMBO WHICH BRINGS LOW CLDS ACRS WED NGT THROUGH THU NGT. FWC/NGM DOESN'T SEEM TO BRING ENOUGH CLDS ACRS WED NGT/THU AS CD AIR ASSOCIATED WITH THE UPR LOW PLUMMETS SE AND S/W'S ROTATE AROUND THE UPR LOW ACRS THE FA. CU RULE WOULD INDICATE PLNTY OF CU ON THU. WL MENTION FLURRIES EXPECT CD AIR ALOFT/PVA COULD KICK OFF A FEW SNOW SHOWERS ON THU. TNGT...MODELS ARE HAVING A HARD TIME COMING TOGETHER ON WHAT TO DO WITH THESE PERSISTANT LOW CLDS. ETA APPEARS TOO FAR SW WITH THE LOW CLD EDGE BASED ON ITS LOW LVL MOIST INITIALIZATIONS AND PROGS. BEST CHOICE BASED ON VSBL SAT TRENDS APPEARS TO BE A COMPROMISE BETWEEN THE NGM AND RUC WITH THE LOW CLDS MOVING INTO THE NERN CORNER OF OUR CWA AND THE REST OF THE AREA CLR TO PARTLY CLDY. MODELS AGREE THE MOST TOMORROW WITH LOW LVLS DRYING OUT A BIT ALLOWING FOR SOME SS. CU DVLPMENT PROGS INDICATE SCT CU. FAVOR WARMER FWC IN NE ZONES AND COOLER ELSEWHERE TNGT DUE TO CLD CVR. MOS NUMBERS CLOSE AND APPEAR REASONABLE TOMORROW AS SS/WK WAA ALLOW FOR THE NICEST DAY OF THE WEEK. FAVOR WARMER MAV WED NGT AND COOLER MAV THU DUE TO EXPECTED CLD CVR. .IND...NONE. KOCH in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 405 PM EST TUE MAR 6 2001 12Z RAOBS/WV LOOP AND RUC ANAL SHOW DEEP ERN TROF UNDER BLOCKING HI IN QUEBEC AND DOWNWND OF RDG OVR WRN CAN. CYC FLOW ARND VORTEX/LO PRES OFF MID ATLANTIC COAST XTNDS WAY BACK INTO GRT LKS E OF SFC HI OVR WRN IA. QUITE A BIT OF LO CLD LINGERS OVR SRN LK SUP IN NLY FLOW BTWN HI TO W AND LO TO E...WITH MOIST AIR (SFC DWPTS ARND 15) OVR SRN ONTARIO. 12Z YPL SDNG SHOWS VERY MOIST LYR BLO SHARP INVRN JUST ABV H925 WITH VERY DRY AIR ABV (PW 0.18"). MQT 88D VWP RETURNS SUG INVRN HERE ARND 4K FEET MSL. STRG MARCH SUN HAS MXD OUT LO CLD OVR SRN ONTARIO/MN/WI AND SW ZNS/ERN CWA (WHERE NLY FLOW DOWNSLOPING OFF SRN ONTARIO) AND NRN LK SUP...BUT CLD HANGING TOUGH IN UPSLOPE AREAS AND IN PLACES IMPACTED BY LONG FETCH ACRS LK. NXT FAIRLY POTENT LOOKING SHRTWV MOVG SEWD THRU SRN MANITOBA. 12Z H3 RAOBS SHOW SHARP HGT RISES OVR WRN CAN IN ITS WAKE...WITH 100KT H3 JET MAX MOVG OVR TOP OF RDG THIS MRNG. MAIN SHORT TERM FCST CONCERNS THIS PACKAGE INCLUDE CLD/TEMP TRENDS TNGT...THEN IMPACT OF MANITOBA SHRTWV LATE TMRW-THU. FOR TNGT...18Z RUC H925 RH FCST APPEARS TO HAVE BEST HANDLE ON CURRENT LO CLD PLACEMENT. ALTHOUGH CLD AREA SHRINKING ATTM...ONCE SUN GOES DOWN AM CONCERNED THAT LO CLD WL REDVLP...ESPECIALLY SINCE LLVL TRAJECTORIES REMAIN OUT OF THE N TNGT FROM 15 DEGREE DWPTS IN SRN ONTARIO AS PLAINS SFC HI SINKS MORE SE THAN MOVG DUE E. RUC H925 RH FCST SHOWS A SLOW DIMINISHING TREND OF HIER RH SO THAT BY 06Z... HIER RH LINGERS ONLY OVR THE NCNTRL ZNS. HAVE KEPT CLDS IN LONGEST OVR BARAGA-MQT-MUN-ISQ WHERE CONTD NNWLY FLOW UNDER LO INVRN WL KEEP CLD ARND LONGEST. GIVEN DWPTS ACRS SRN ONTARIO AND PASSAGE OF THIS AIR ACRS LK SUP...HAVE GENERALLY GONE ABV GUIDANCE FOR MINS. BUT LWR TEMPS IN FAR W...WHERE CLRG ALREADY IN PROGRESS AND CLOSER TO DRIER AIR IN MN. AVN APPEARS TO HAVE BEST RUN-TO-RUN CONTINUITY WITH SHRTWV PROGGED TO DIG INTO NW GRT LKS WED-THU. BUT ETA/NGM IN GOOD AGREEMENT ON DVLPG CUTOFF LO AS WELL AS UPR JET MAX NOW RIDING OVR WRN RDG DIGS INTO MEAN ERN TROF...LENDING HI CONFIDENCE TO MODEL FCST PER PMDHMD. HAVE FOLLOWED SLGTLY DEEPER AVN FOR LARGER SCALE FEATURES GIVEN CURRENT HI AMPLITUDE/BLOCKING PATTERN AND MODEL TRENDS...BUT USED ETA FOR LLVL DETAILS. AVN SHOWS H7-3 QVECTOR CNVGC INCRSG ON WED AHD OF DIGGING SHRTWV WITH DYNAMICS REACHING SE ZNS DURG AFTN. THINK DRYNESS OF ANTECEDENT AIRMASS DEPICTED ON 12Z YPL SDNG MEANS ASSOCIATED OMEGA WL GO INTO MOISTENING ATMOSPHERE...SO RESTRICTED MENTION OF PCPN TO WRN HALF WHERE AT LEAST 6HRS OF H7-3 FORCG OCCURS. WENT CATEGORICAL IN WRN ZNS WHERE DVLPG WLY FLOW/LK MOISTENING AND H85 TEMPS LO ENUF FOR LK ENHANCEMNT. TEMPS ON HI SIDE OF MOS (TEMPS HAVE REACHED MID 30S IN MN TDAY)...ESPECIALLY OVR THE E WHERE THERE WL BE A FEW HRS OF SUN. AVN SHOWS H5 LO PASSING NW-SE OVR CWA FM ONT-MNM WED NGT WITH INVRTD TROF AXIS LAYING WNW FM SFC LO POSITION OVR NRN LWR MI AT 12Z THU THRU SRN CMX COUNTY...JUST ON N SIDE OF UPR LO TRACK. AVN SHOWS H7-3 QVECTOR CNVGC DEPARTING THU AFTN...BUT SLOWER TREND TO DEPARTURE OF DEEPENING CUTOFF/DYNAMICS PSBL IN BLOCKING PATTERN. HAVE OPTED FOR WINTER STORM WATCH FOR KEWEENAW ZNS WHERE AVN H85-5 QVECTOR CNVGC... MESOETA FCST H95 CNVGC/CYC FLOW PHASE WITH NWLY H100-85 WND DIRECTION AND H7-5 THERMAL TROF TO RESULT IN LIKELIHOOD OF 12-18HR LK ENHANCED EVENT WITH DELTA-T ARND 13-15C. ADDING CONFIDENCE TO THIS SCENARIO IS ETA FCST SDNGS SHOWING NO INVRN UNDER UPR THERMAL TROF WITH DEEP MSTR THRU LWR TROP. LES CHART SUGS 1-3"/6 HRS FOR ENHANCEMENT TO ADD ON TO 2 INCHES FM XPCTD SYS SN (PW 0.25-0.33")... SO WL MENTION 10-12" OF SNOW IN 24HR PD. THOSE PLACES THAT SEE NO LK MOISTENING WL GET ONLY SCT -SHSN OUT OF THIS SYS...ESPECIALLY THOSE PLACES S OF UPR LO TRACK. RIGHT NOW DYNAMICS AND WND/THERMAL FIELDS DON'T COME INTO GOOD ALIGNMENT TO WARRANT HEADLINE ANYWHERE ELSE. BUT LATER SHIFTS WL HAVE TO EVALUATE NEED FOR HEADLINE IN OTHR LK SUP BORDER COUNTIES... ESPECIALLY IF UPR LO TAKES A TRACK FARTHER S. EXTENDED MODELS CONT TO TREND SLOWER IN BRKG DOWN BLOCKING HI PRES OVR NE CAN LATE THIS WEEK...YET TRY TO PUSH CUTOFF LO THAT DVLPS OVR THE LKS ON THU EWD ON FRI. GIVEN BLOCKING PATTERN IN PLACE...MODEL BIAS TO BRK DOWN THESE PATTERNS TOO QUICKLY...AND SHORTER TERM TREND TO MAINTAIN UPR HI OVR QUEBEC...HAVE TRENDED TOWARD SLOWER CANADIAN AND MRF ENSEMBLE MEMBERS THAT SHOW CYC FLOW LINGERING ON FRI. SHRTWV RDGING TO FOLLOW ON SAT...THEN MODELS INDICATE SHRTWV PASSAGE SUN INTO MON TIMEFRAME. MODELS INDICATE UPR RDGING FCST IN WRN CAN AND INTO GREENLAND EARLY NXT WEEK WITH DVLPMNT OF BROAD TROF ACRS CNTRL NAMERICA...ALTHOUGH CONSENSUS ON THIS SOLN LWR THAN YDAY. ECMWF DVLPS DEEP LO OVR CNTRL PLAINS...BUT LACK OF PHASING OF NRN AND SRN STREAMS AND RATHER BROAD NATURE OF TROF SUGS WEAKER MRF SOLN MORE ACCURATE. AT THIS TIME...WL CARRY CHC OF SN ON SUN...THEN A CHC OF SHSN ON MON AS SOMEWHAT COLDER AIR FOLLOWS SHRTWVS...THEN DRY ON TUE. COORDINATED WITH APX. .MQT...NONE. KC mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NORTH PLATTE NE 242 PM CST TUE MAR 6 2001 ...CHALLENGE TO BE CLOUDS AND TEMPS... MODELS INITIALIZED SIMILAR WITH UPPER LOWS SITUATED OVER EASTERN PACIFIC AND CAROLINA COAST WITH RIDGING/NORTHWEST FLOW OVER PLAINS. AT THE SURFACE...HIGH PRESSURE RIDGING FROM WESTERN ONTARIO SOUTH TO EASTERN TEXAS WITH WEAK TROUGH INTO EASTERN COLORADO/NEBRASKA PANHANDLE. OVERALL SOLUTIONS QUITE SIMILAR AS WELL WITH EAST COAST LOW MOVING OFFSHORE AS NEXT SYSTEM PUSHES INTO NORTHERN BAJA BY 24 HOURS...NORTHWEST FLOW OVER NORTHERN PLAINS...BRUSHING WESTERN NEBRASKA...CONTINUES TO BE FOCUS FOR WEAK DISTURBANCES. AS STRONG SYSTEM DROPS OUT OF CENTRAL CANADA BY 36 HOURS...CUTOFF LOW IN SOUTHWEST WILL SLOWLY GET CAUGHT UP IN NORTHERN STREAM FLOW AND WILL EVENTUALLY MOVE ACROSS SOUTHERN PLAINS. AS UPPER RIDGE CONTINUES OVER NORTHWEST CONUS...SURFACE HIGH PRESSURE WILL CONTINUE TO BE DISPLACED INTO CENTRAL AND NORTHERN PLAINS THROUGH THE PERIOD. WITH ALL THIS IN MIND...WILL UTILIZE AN AVN/ETA BLEND...FAVORING ETA/RUC FOR BOUNDARY LAYER FEATURES DUE TO GREATER RESOLUTION/HANDLING OF CURRENT STRATUS. TONIGHT...QUESTION REMAINS HOW FAR WEST WILL STRATUS EXTEND TONIGHT. CURRENT TRENDS PUSHED STRATUS A BIT FURTHER EAST THAN YESTERDAY... WITH WARMER AIR BEHIND IT. HOWEVER...RUC AND 15KM ETA BOTH INDICATE WESTWARD MOVEMENT OF CLOUDS AFTER 00Z...ESPECIALLY IN NORTHERN CWA. AFTER PAST COUPLE OF DAYS...AND WITH CURRENT DEW POINTS IN THE MID TO UPPER 30S UNDER THE CLEAR SKIES...AND DIMINISHING WINDS OVERNIGHT... WOULD EXPECT LOW CLOUDS AND FOG TO RETURN ONCE AGAIN TO ENTIRE CWA. THIS WILL LIMIT LOWS TONIGHT...WITH READINGS GENERALLY IN THE LOWER TO MID 20S. *** AFTER FURTHER REVIEW...BOTH ETA AND AVN MIXING DOWN MUCH DRIER AIR ON THE 290K ISENTROPIC SURFACE...AND WITH NORTH WINDS...LOW CLOUDS NOT GOING TO ADVECT BACK INTO REGION. HOWEVER...WITH HIGH DEWPOINTS...FOG A POSSIBILITY...ESPECIALLY IN THE WEST. WEDNESDAY...MORNING FOG TO BURN OFF QUICKLY IN WEST...WILL GO MOSTLY SUNNY ENTIRE CWA. THIS ALSO SUPPORTED BY WEAK SUBSIDENCE ALONG WITH DRIER AIR ALOFT. ETA TRYING TO HINT AT SOME BOUNDARY LAYER MOISTURE/STRATUS...NORTHWEST WINDS SHOULD HELP TO KEEP THAT TO A MINIMUM. AS SURFACE LOW DEVELOPS IN NORTHERN MEXICO...HIGH PRESSURE WILL CONTINUE TO FILTER INTO THE PLAINS...KEEPING WINDS NORTHERLY AT 5 TO 15 MPH...BECOMING LIGHT AND VARIABLE. WITH WESTERLY COMPONENT TO WINDS IN PANHANDLE...WARMEST TEMPS THERE...COOLER TO THE NORTHEAST WITH 850 MB TEMPS RANGING FROM 6C WEST...TO -2C NORTHEAST. WILL LEAN TOWARD SLIGHTLY COOLER MAV NUMBERS...MID 50S FAR WEST...MID TO UPPER 40S CENTRAL...UPPER 30S/LOWER 40S EAST. WEDNESDAY NIGHT...UPPER SYSTEM WELL TO OUR SOUTH...WITH WEAK RIPPLE IN NORTHWEST FLOW TO MOVE THROUGH AREA. AT THE SURFACE...RIDGE AXIS TO EXTEND OVER EASTERN PORTIONS OF STATE. THIS WOULD BE SIMILAR TO WHAT WE HAVE BEEN EXPERIENCING LATELY...WITH THE CHANCE FOR STRATUS AND FOG TO DEVELOP AGAIN. WILL GO MOSTLY CLOUDY WEST...PARTLY CLOUDY EAST. LOWS GENERALLY IN THE TEENS AND 20S WITH COLDEST NORTHEAST. THURSDAY...HIGH PRESSURE CONTINUES OVER EASTERN PORTION OF STATE... AGAIN SETTING THE STAGE FOR STRATUS IN WESTERN CWA...MOSTLY SUNNY FAR EAST. WITH LACK OF CONFIDENCE IN MODELS HANDLING BOUNDARY LAYER MOISTURE THIS FAR OUT...WILL GENERALLY GO PARTLY CLOUDY. WITH 850 MB TEMPS AGAIN FROM THE 6C TO -4C RANGE...HIGHS IN THE 30S EAST...NEAR 50 FAR WEST. THURSDAY NIGHT...AVN DEVELOPS WEAK LOW OVER NORTHEAST COLORADO LATE...WITH HIGH PRESSURE CENTERED OVER EASTERN NEBRASKA. THIS WILL SET THE STAGE FOR DECENT SOUTHERLY FLOW OVER MOST OF THE CWA... ADVECTING IN MORE BOUNDARY LAYER MOISTURE. WITH UPPER RIDGE AXIS JUST WEST OF CWA...NO FORCING WITH THE EXCEPTION OF SOME VERY WEAK ISENTROPIC LIFT IN THE LOWEST LAYERS. THIS COULD RESULT IN SOME DRIZZLE...BUT AT THIS TIME WILL JUST GO MOSTLY CLOUDY. SOUTHERLY WINDS WILL HELP TO KEEP ATMOSPHERE MIXED...AND WITH CLOUD DECK TO MINIMIZE RADIATIONAL COOLING...LOWS IN THE 20S. EXTENDED...AS UPPER LOW APPROACHES THROUGH NORTHERN STREAM...SURFACE LOW TO DEVELOP IN EASTERN SLOPES...ALLOWING FOR CONTINUED SOUTHERLY FLOW. AVN QPF INDICATING SOME PRECIP IN CWA...AND WILL WORD SLIGHT CHANCE OF RAIN ENTIRE CWA. HIGHS INTO THE 40S EAST...TO LOWER 50S WEST. COLD FRONT APPROACHES NORTHERN CWA BY 12Z SATURDAY MORNING... PUSHING THROUGH CWA ON SATURDAY. AGAIN...AVN CRANKING OUT PRECIP OVER ENTIRE CWA...AND WILL GO CHANCE OF RAIN AND SNOW ENTIRE CWA AS COLD AIR SETTLES IN BETWEEN 18Z AND 00Z. LOWS ON SATURDAY IN THE 20S... HIGHS IN THE 30S AND 40S...BUT WITH FALLING AFTERNOON TEMPS. IN BETWEEN SYSTEMS ON SUNDAY...AND WILL GO MAINLY DRY WITH LOWS IN THE 20S...HIGHS IN THE MID 30S TO MID 40S. UPPER LEVEL TROUGH DIGS INTO CENTRAL PLAINS BY MONDAY AFTERNOON...WITH COLD FRONT DROPPING THROUGH ENTIRE CWA. WILL GO WITH CHANCE OF SNOW...LOWS IN THE 20S...HIGHS IN THE 30S. NORTH FLOW WILL CONTINUE WITH COLD AIR IN PLACE OVER REGION. WILL CONTINUE SLIGHT CHANCE OF LIGHT SNOW...LOWS IN THE TEENS...HIGHS IN THE 30S. .LBF...NONE $$ M. MUTCHLER ne