SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BOISE IDAHO 840 PM MST WED FEB 7 2001 NOT EXACTLY SURE WHY THE STRATOCUMULUS PATCH COVERING THE MAGIC VALLEY IS SO PERSISTENT THIS EVENING. THE MOISTURE IS TRAPPED BELOW THE SUBSIDENCE INVERSION ALOFT. THE CLOUD MASS IS HANGING BACK BEHIND THE MAIN DEFORMATION FIELD WITH VIRTUALLY NO CHANGE TO THE N AND W BACK EDGES. RUC AND ETA MODEL SOUNDINGS FOR TONIGHT SHOW GENERAL COOLING OF THE ENTIRE COLUMN WITH THE INVERSION ALOFT STAYING IN TACT. WITH THE SURFACE GRADIENT SLACKING OFF TONIGHT WILL HAVE TO ASSUME THE CLOUDS WILL PERSIST AND MAY EVEN SPREAD BACK WESTWARD A BIT BEFORE MORNING. TEMPERATURES ARE STARTING TO DROP OFF NOW THAT THE WINDS ARE DYING DOWN. CURRENT FORECAST LOOKS ON TARGET WITH TRENDS...WILL ADJUST MAGIC VALLEY FORECAST FOR THE CLOUDS TONIGHT. JANNUZZI .BOI...NONE. id AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GOODLAND KS 800 PM MST WED FEB 7 2001 DRIER AIR MOVING OUT OF THE NEBRASKA PANHANDLE TOWARD NORTHWEST PART OF FA...AND TEMPERATURES HAVE ALREADY FALLEN BELOW FORECASTED MINS. HAVE REDUCED MINS BY A CATEGORY IN ALL ZONES WITH 15 TO 20F IN THE NORTHWEST AND AROUND 25 IN THE SOUTHEAST. FZDZ CHANGES PHASE TO FLURRIES AROUND 17F BASED ON TREND IN UPSTREAM OBS. ONLY EXPOSED SURFACES GETTING THE LIGHTEST COATING OF ICE SO FAR...SO NO ADVISORY NECESSARY. WINDS HAVE DIMINISHED TO 10 TO 15 MPH AS COLD FRONT HAS SURGED INTO THE ARKANSAS RIVER VALLEY OF SOUTHWEST KANSAS AND SOUTHEAST COLORADO...SO HAVE REDUCED WIND SPEEDS AND TWEAKED DIRECTION. LATEST RUC ALSO SUGGESTS TRACE PRECIP WILL END OVER THE FA BETWEEN 06Z AND 12Z JUST BEFORE ARRIVAL OF HIGHER PW AIR. .GLD...NONE. ENTWISTLE ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1001 PM EST WED FEB 7 2001 WILL MAINTAIN WARNINGS AND ADVISORIES AS IS. PROFILER DATA OVER ERN KANSAS SUPPORTS 50 KT LLJ...GIVING CREDENCE TO DEVELOPING STRONG ISENTROPIC/WARM AIR ADVECTION EVENT. ADDITIONAL IR ENHANCEMENT IS BEGINNING TO TAKE PLACE OVER IOWA...AT THE HEAD OF THIS LLJ...AND DES MOINES RADAR IS ALSO LIGHTING UP ATTM. PCPN A BIT BEHIND FROM PREVIOUS THINKING...BUT IT SHOULD BE HITTING THE SHORES OF LAKE MICHIGAN SHORTLY AND REACHING THE EASTERN CWA BY 06Z. OF COURSE THE LONGER IT CAN BE DELAYED...THE LESS SNOW AND ICE ACCUMULATION PRIOR TO THE WARM AIR SETTING IN. THE RUC HINTS AT A LITTLE QUICKER CHANGE OVER TO ALL RAIN...BUT THIS MAY BE ONLY BY AN HOUR OR TWO. ACCUMULATION TOTALS UP THRU MORNING LOOK FINE. QUICK LOOK AT THE 00Z ETA SHOWS EXPLOSIVE PCPN DEVELOPMENT ACRS CENTRAL MICHIGAN WHERE 2 - 4 INCHES OF SNOW COULD EASILY FALL PRIOR TO THE DAYBREAK CHANGE OVER. PRESSURE GRADIENT FAIRLY BAGGY OVER THE REGION ATTM AND WILL TRIM WINDS DOWN AS A RESULT...ALTHOUGH WE WILL SEE SOME INCREASE BY MORNING. WILL BE GIVING STRONG CONSIDERATION OF A HIGH WIND ADVISORY/WATCH FOR THURSDAY NIGHT/FRIDAY AS THE H8 LLJ APPROACHES 90KTS ON FCST SOUNDINGS! THIS COULD TRANSLATE TO WIND GUSTS IN THE 55-60 MPH RANGE AT THE SURFACE. HIGHEST THREAT AT THIS POINT APPEARS IN THE SOUTHEASTERN CWA. WILL MAKE THIS CALL AT NEXT SCHEDULED ISSUANCE AT 4AM. JK .GRR...WINTER STORM WARNING TONIGHT AND THURSDAY MORNING... MIZ037>040-043>046-051-052. .......WINTER WEATHER ADVISORY TONIGHT AND EARLY THURSDAY MORNING... MIZ050-056>059-064>067. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 951 PM EST WED FEB 7 2001 SNOW IS FALLING IN EAST WISCONSIN WITH THE RADAR AT KGRB SHOWING THAT THE SNOW IS MOST LIKELY FALLING OUT OVER LAKE MICHIGAN AS WELL. AT 02Z, CAD AND MBL WERE REPORTING SNOW OVER THE SOUTHERN MOST COUNTIES IN THE CWFA. 00Z RUC AND 18Z MESOETA CORRELATE FAIRLY WELL WITH THE RADAR. SO WILL KEEP THE GOING FORECAST, EXCEPT FOR SOME MINOR TIMING IN THE ZONES THAT MAY NEED TO BE ADJUSTED. NEAREST AREA OF MIXED PRECIPITATION WAS IN SOUTHERN WISCONSIN WHICH AGREES WITH THE 850 TEMP OFF OF THE RUC AS WELL AS THE SOUNDINGS AND THE NEW ETA THAT IS JUST ARRIVING. .APX...WINTER STORM WARNING...TONIGHT AND THURSDAY MORNING...MIZ031>036-041-042. WINTER WEATHER ADVISORY...TONIGHT AND THURSDAY MORNING... MIZ025-030. WINTER STORM WATCH...THURSDAY NIGHT AND FRIDAY MORNING... MIZ008>015. LUTZ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1045 AM EST WED FEB 7 2001 12Z RAOBS/WV LOOP/RUC ANAL SHOWS BROAD UPR RDG OVR CNTRL CONUS SANDWICHED BTWN DIGGING TROF INTO CA AND TROF ALG E CST. SHRTWV NOTED LIFTING ENEWD INTO WRN SD...AND ENHANCED CLD AHD OF SYS AND IN ENTRANCE OF 110KT H3 JET MAX ROUNDING TOP OF RDG IN NW GRT LKS EXPANDING ENEWD TOWARD NW GRT LKS. AT THE SFC...RDG OF HI PRES XTNDS FM NRN MN SEWD INTO OH VALLEY. CWA IN WNLY FLOW ON NRN FLANK OF THIS RDG AND S OF LO PRES TROF IN SRN ONTARIO WITH VERY DRY AIR AT H85. 12Z GRB SDNG SHOWS BASE OF INVRN ARND H9 WITH DRY AIR ABV. GOES DERIVED SDNG FOR MQT AT 12Z INDICATES INVRN DOWN TO H925 (CONFIRMED BY HGT OF RPRTD WND ON 88D VWP) WITH DRY AIR IN MID TROP...AND 88D/SFC OBS/SAT PIX SHOW WEAK LES EVENT WINDING DOWN WITH NO REFLECTIVITY OVR 10DBZ AND FLURRIES RPRTD NOW AT ERY. LO PRES BEGINNING TO TAKE SHAPE ON LEE SIDE OF CNTRL ROCKIES IN ADVANCE OF MAIN SHRTWV DIGGING THRU CA. AREA OF SN FALLING UNDER ENHANCED CLD IN NRN PLAINS AHD OF SHRTWV LIFTING NEWD INTO RDG...WITH UPR DVGC IN ENTRANCE OF UPR JET... IMPRESSIVE H85-5 QVECTOR CNVGC...VIGOROUS ISENTROPIC LIFT ON 290K SFC...MSTR CNVGC...AND H85-7 FRONTOGEN CONTRIBUTING TO AREA OF ENHANCED H7 UVV. LEADING EDGE OF THIS SN HAS REACHED STC-MSP IN SCNTRL MN AT 15Z. MAIN FCST CONCERNS FOR TDAY CENTER ARND CLD/TEMP TRENDS AND HOW FAR ENE SN TO SW WL SPRD LATE. OF THE 00Z/06Z MODELS...00Z AVN F12 HAD BEST HANDLE ON MSLP PATTERN AT 12Z AND LOCATION OF PCPN IN NRN PLAINS. ALL MODELS SHOW SLOWLY WEAKENING SFC-H85 RDG AXIS MOVG SLOWLY NEWD TDAY TO A POSITION OVR NRN CWA/SRN LK SUP BY 00Z. SHRTWV OVR WRN SD PROGGED TO SHEAR OUT INTO TOP OF UPR RDG AS MEAN TROF REMAINS IN W AND IT CONTS INTO CONFLUENT UPR FLOW WITH WEAKENING UPR DVGC/DYNAMICS/UVV SPRDG INTO CWA THIS AFTN BUT UNABLE TO SATURATE DRY LO-MID TROP. THIS SCENARIO SUGS DSPTG LO CLD IN THE E BUT THEN THICKENING HI TO MID CLD SW-NE. 00Z AVN...12Z RUC AND 12Z ETA INDICATE LEADING EDGE OF MEASUREABLE PCPN REACH SW BORDER ZNS TOWARD 00Z. SINCE NEW ETA SHOWS SHARPEST H85 THERMAL GRADIENT AND H100-7 MSTR CNVGC REMAINING WELL TO S THRU 00Z...WL LEAVE JUST MENTION OF FLURRIES LATE ACRS SW ZNS. FCST MAX TEMPS CONSISTENT WITH UPSTREAM RDGS YDAY AND LATEST MOS GUIDANCE...SO FEW CHGS NECESSARY XCPT TO LWR FCST MAX A TAD OVR SW WHERE THICKER HI CLDS POISED TO MOVE IN SOON. .MQT...NONE. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MORRISTOWN TN 908 AM EST WED FEB 7 2001 WILL BE GETTING AN EARLIER UPDATE OUT THIS MORNING. CLOUDS...A LOW DECK OF AC...HAVE SPREAD ACROSS MOST OF THE CWA. 06Z MESO-ETA AND 12Z RUC HAD SOME INDICATION OF THIS...BUT NOT AS WELL AS MIGHT BE EXPECTED. THE MOISTURE LIES BETWEEN 80H AND 70H. 06Z MES0-ETA INDICATED VERY GOOD WAA AT 800 AND 750 MBS...BUT WAS WEAKER WITH THE WAA AT 80H AND 70H. IN ANY EVENT...THIS WAA CONTINUES THROUGH THE DAY...AND THE ASSOCIATED CLOUDS EXPECTED TO BE AROUND FOR A LONGER TIME AND THICKER. WILL UPDATE FOR CLOUDS...AND WITH MORE CLOUDS WILL LOWER TEMPS A BIT. THE MESO-ETA INDICATED THAT MOISTURE SLOWLY LIFTS NORTHWARD THROUGH THE DAY. WITH THIS IDEA...WILL STILL HAVE SE TN MOSTLY SUNNY THIS AFTERNOON...HAVE LATE CLEARING FOR THE CENTRAL VALLEY...AND JUST MOSTLY CLOUDY FOR NE TN AND SW VA. .MRX... NC...NONE. TN...NONE. VA...NONE. RBP tn TEXAS/OKLAHOMA PANHANDLES FORECAST DISCUSSION NATIONAL WEATHER SERVICE AMARILLO TX 415 AM CST THU FEB 8 2001 SURFACE ANALYSIS SHOWS BROAD SURFACE LOW PRESSURE ACROSS THE CENTRAL ROCKIES WITH A SOUTHWEST LOW SITUATED OVER WESTERN ARIZONA. THIS UPPER TROUGH WILL BEGIN TO SLIDE EAST TODAY. IN ADDITION...A COLD FRONT WAS POSITIONED ACROSS THE OKLAHOMA PANHANDLE. MOST OF THE MODELS WERE HANDLING THE FRONT POORLY WITH THE ETA AND RUC LOOKING THE BEST. THIS WILL BRING THE FRONT SLOWLY SOUTH TODAY WITH HIGH UNCERTAINTY IF IT WILL HANG UP OR NOT. THE FRONT MAY STALL NEAR THE CANADIAN RIVER THIS AFTERNOON OR IT MAY COME THROUGH AMARILLO LATE THIS MORNING. EITHER WAY...TEMPERATURES WILL STAY QUITE COLD BEHIND THE FRONT AS TEMPERATURES WARM UP SOUTH AND EAST OF THE FRONT CAUSING DESTABALIZATION TO OCCUR IN THE SOUTHEASTERN ZONES. DYNAMICS APPEAR FAVORABLE FOR A FEW THUNDERSTORMS AROUND CHILDRESS LATE THIS AFTERNOON SO WILL CONTINUE A MENTION OF STORMS SOUTHEAST. THE BETTER UPPER-LEVEL ENERGY APPEARS TO BE NORTH THIS AFTERNOON WHICH SHOULD BREAK OUT FREEZING RAIN THERE. WILL ISSUE A FREEZING RAIN ADVISORY ACROSS MOST OF THE NORTH. SNOW ACCUMULATIONS SHOULD BE CONFINED TO THE FAR NORTHWEST THIS AFTERNOON SO WILL ISSUE A WINTER STORM WARNING FOR THIS AFTERNOON THROUGH TONIGHT THERE. TONIGHT... THE COLD FRONT SHOULD PICKUP SPEED AND CLEAR THE SOUTHEAST THIS EVENING. THIS WILL CHANGE PRECIPITATION TO SNOW IN THE SOUTHWEST EARLY. RAIN SHOULD CONTINUE IN THE SOUTHEAST CHANGING TO SLEET AND SNOW OVERNIGHT. THE SNOWFALL WILL CONTINUE THROUGH DAYBREAK ON FRIDAY. AMOUNTS ARE STILL UNCERTAIN SO WILL ISSUE A WINTER STORM WATCH FOR TONIGHT AS SNOW WILL SPREAD ACROSS THE NORTHERN ZONES WITH THE WIND BLOWING IT AROUND TONIGHT. IN THE SOUTH...ACCUMULATIONS SHOULD BE LIGHTER SO WILL GO UP TO AN INCH POSSIBLE. UNCERTAINTY FOR SNOWFALL TOTALS STILL REMAINS. THE SYSTEM WILL EXIT FRIDAY MORNING CUTTING OFF THE PRECIPITATION AND PARTIALLY CLEARING SKIES. HIGH PRESSURE FROM NORTHERN CANADA WILL SETTLE INTO THE CENTRAL PLAINS FRIDAY AND FRIDAY NIGHT DROPPING TEMPERATURES INTO THE TEENS OVER MUCH OF THE NORTHERN ZONES. FOR THE EXTENDED PERIOD...A QUICK WARM UP IS IN STORE AS THE HIGH LOSES ITS GRIP ON THE REGION SATURDAY AND A LEE TROUGH DEVELOPS. THIS WILL RETURN WINDS TO THE SOUTHWEST WITH DRY CONDITIONS PREVAILING THROUGH MIDWEEK. PRELIM CCF... AMA 54/20 31/19 47 352 DHT 31/15 25/15 45 673 .AMA... TX...WINTER STORM WATCH TONIGHT TXZ001-006. FREEZING RAIN ADVISORY TODAY TXZ001>006 OK...WINTER STORM WARNING THIS AFTERNOON AND TONIGHT OKZ001. WINTER STORM WATCH TONIGHT OKZ002-003. FREEZING RAIN ADVISORY TODAY OKZ002-003. CB tx AREA FORECAST DISCUSSION...CORRECTION NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX 333 AM CST THU FEB 8 2001 LOW LEVEL MSTR HAS RETURNED TO W TX IN ADVANCE OF DEEP SRN STREAM SYSTEM LOCATED SRN CA. IN ADVANCE OF TROF A CONVEYOR OF MID/UPPER LEVEL PACIFIC MSTR IS NOTED ACROSS W TX WHILE 50KT LLJ IS SHOWN BY KMAF VWP. ATTM A FEW LIGHT SHRA ARE NOTED ACROSS AREA WITH LI'S AT KMAF AROUND MINUS 1. PRESENCE OF LOW LEVEL MSTR WILL COMBINE WITH ONLY MARGINAL LR'S TO PRODUCE MEAGER SURFACE BASED CAPES. RUC SHOWS CAPES NEARING 900 J/KG AT KMAF BY 12Z THIS MORNING BUT VEERING WIND PROFILES QUICKLY LOWER INSTABILITY THRU MORNING HRS. AS SUCH NE-SE AREAS WILL BE MOST FAVORED FOR SHRA/TSRA. WINDY CONDITIONS MORE LIKELY THOUGH. WILL TEND TO SIDE WITH AVN AS REAL-TIME WSM PROFILER 25H DATA AND SURFACE ANALYSIS ARE MORE IN AGREEMENT WITH AVN 6HR FCST. APPLYING HIGH WIND DECISION TREE GIVES 30-40 MPH WITH HIGHER GUSTS IN THE SW MTNS. HOWEVER STRONG DOWNWARD MOTION ISN'T EXPECTED TO MOVE INTO SW TX MTNS UNTIL AROUND 00Z. ABUNDANCE OF MID/UPPER CLOUDS EXPECTED TO INHIBIT WINDS TOO AND FOR NOW WILL CONTINUE WITH GENERALLY WINDY WORDING. WIND COMBINED WITH WARM TEMPS/LOWERING RH'S RAISES FIRE WX CONCERNS IN SW TX MTNS ALSO. TIGHTENING MSL PRESSURE GRADIENT AND DOWNWARD FORCING WILL KEEP WINDS UP BEYOND THE TYPICAL DIURNAL PATTERN TONIGHT IN PB. COOLER AIR TO MOVE INTO RGN FRIDAY WITH THCK FALLS AND SURFACE HIGH PRESSURE. SW MID LEVEL FLOW WILL FAVOR AMPLIFICATION OF LOW LEVEL THERMAL RIDGE THIS WEEKEND. EXTENDED SEEMS TO HAVE HANDLE ON THIS SCENARIO AND WILL MAKE LITTLE CHANGE. MAF 68/34/52/25 2200 LSA 61/32/51/24 2-00 E41 68/34/52/25 2200 MRF 64/27/55/21 2-00 CNM 61/34/54/25 2-00 .MAF... TX...NONE. NM...NONE. tx WEST CENTRAL AND SOUTHWEST FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAMPA BAY AREA - RUSKIN FL 931 AM EST THU FEB 8 2001 TRAPPED MOISTURE UNDER STRONG SUBSIDENCE INVERSION LEAD TO SOME PATCHY FOG ACROSS THE FA EARLIER THIS MORNING...BUT AS I WRITE MOST IS JUST ABOUT GONE. VISIBLE SATELLITE LOOP SHOWS SOME MARINE STRATO- CU MOVING INTO POLK COUNTY IN DEEP EASTERLY FLOW...BUT AS MIXING TAKES PLACE MOST OF THESE CLOUDS SHOULD TEND TO ERODE AS THEY MOVE WEST...SO A GOOD DEAL OF SUNSHINE IS STILL EXPECTED. WILL REMOVE EARLY MORNING FOG WORDING IN A LATE MORNING UPDATE...OTHERWISE THE REST OF THE ZONES LOOK IN GOOD SHAPE. TRENDS FROM C-MAN AND OFFSHORE BUOYS AS WELL AS THE EXPECTED INCREASED GRADIENT ADVERTISED BY LATEST 13Z RUC AND 12Z MESO-ETA SUPPORTS BUMPING UP WINDS TO SCEC CRITERIA OVER THE COASTAL WATERS FOR THE AFTERNOON HOURS AND 1030 AM UPDATE WILL REFLECT THIS. THANKS FOR COORD KTLH. .TBW...SCEC BONITA BEACH TO THE SUWANNEE RIVER OUT 60 NM INCLUDING TAMPA BAY THIS AFTERNOON. MCMICHAEL fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1040 AM EST THU FEB 8 2001 WILL LET WINTER WEATHER ADVISORY EXPIRE AT NOON. PRECIP TAPERING OFF TO DRIZZLE BY NOON ACROSS ADV AREA AS TEMPS HOLD STEADY IN THE LOWER 30S. SLOW IMPROVEMENT TO UNTREATED ROADS...BUT DONT EXPECT ANY MORE FREEZING PRECIP DURING THE AFTERNOON. WILL ADD MENTION OF FOG FOR THE AFTERNOON ACROSS SOUTHERN HALF OF CWA AS DEW POINTS RISE TO MID 30S OVER SNOW COVERED GROUND. WILL ALSO CUT MAXES A BIT FROM INTERSTATE 96 NORTH AS LATEST RUC AND MESO-ETA KEEP THE WARM FRONT SOUTH OF I-96 UNTIL 00Z. LOTS OF CONCERNS FOR SECOND AND THIRD PERIOD...WHICH WILL BE ADDRESSED IN AFT ZONE PKG. OSTUNO .GRR...WINTER WEATHER ADVISORY UNTIL NOON THURSDAY ...MIZ037>040-043>046-050>052-056>059. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1030 AM EST THU FEB 8 2001 12Z RAOBS/WV LOOP SHOW BROAD UPR RDG OVR GRT LKS IN SPLIT FLOW E OF NRN BRANCH TROF OVR NRN ROCKIES AND VIGOROUS SRN BRANCH CUTOFF LO OVR AZ. 110KT H3 JET MAX NOTED OVR DAKOTAS IN CONFLUENT FLOW BTWN THESE BRANCHES...AND THIS JET SUPPORTING A SFC-H85 WAVE ON SHARP BUT SHALLOW FNT ACRS MID-UPR MS VALLEY. ANOTHER 100+KT JET OVR NRN NM. IR LOOP SHOWS EXPANDING AREA OF COLDER CLD TOPS ACRS NRN PLAINS ASSOCIATED WITH THESE JETS AND UPR DVGC. CWA DOMINATED BY GENERAL ELY CYC FLOW WELL N OF THIS BNDRY WITH SOME ISENTROPIC LIFT IN ENTRANCE RGN OF ANOTHER 100KT H3 JET MAX OVR SE ONTARIO. 12Z GRB SDNG SHOWS FNTL INVRN AT H925. INCRSG LLVL MOISTENING (MQT VWP SHOWS 20KT ESELY FLOW AT 2-3K FT AGL) ONGOING WITH DWPT UP TO 27 AT MNM. HOWEVER... DRYING ALF DEPICTED ON WV/IR LOOP (12Z GRB SDNG INDICATES DRYING ABV H6) AND H85-5/H5-3 QVECTOR DVGC PER 12Z RUC LIMITING PCPN INTENSITY TO JUST SPOTTY -SN. IN FACT...LATEST 88D REFLECTIVITY TREND INDICATES DCRSG -SN COVG. -FZDZ OBSVD TO S WHERE SAT SUGS DRIER AIR XTNDS FARTHER DOWN INTO LWR TROP. RELATIVELY HI LLVL STABILITY AND CONSIDERABLE LLVL SHEAR DEPICTED ON RUC ANAL/FCST SDNGS FOR CMX LIMITING POTENTIAL FOR ANY LK ENHANCED SN IN THE KEWEENAW DESPITE ELY LLVL WND. MAIN FCST CONCERNS TDAY CENTER ARND PCPN TRENDS. 12Z RUC APPEARS TO HAVE BEST HANDLE ON CURRENT MSLP/PCPN AND SHOWS UPR JET MAXES LIFTING NEWD THRU UPR MS VALLEY AND TOWARD ONTARIO TDAY. CWA PRETTY MUCH REMAINS IN ACYC SIDE OF THESE JETS WITH WEAK UPR CNVGC AND H5-3 QVECTOR DVGC...ESPECIALLY OVR THE ERN ZNS DESPITE CONTD LLVL MOISTENING. BEST OPPORTUNITY TO GET SOME UPR DVGC AND DEEPER MSTR WL BE OVR THE WRN ZNS. IN FACT...RUC DEPICTS FAIRLY INTENSE H85-5 QVECTOR CNVGC OVR WRN ZNS LATER THIS AFTN. UPR LVL SUBSIDENCE WITH LLVL MOISTENING FAVORS -FZDZ...SO WL KEEP MENTION OF THIS PCPN IN E AND CNTRL AND ADD TO WRN ZNS THRU EARLY THIS AFTN. BUT THEN XPCT INCRSG SN OVR WRN ZNS DURG AFTN TO COINCIDE WITH ARRIVAL OF H85-5 QVECTOR CNVGC AND COLDER CLD TOPS. 3G/KG AVBL ON 290K ISENTROPIC SFC FOR PCPN IN WAD PATTERN...SO OFF AND ON SN FOR 6 HRS SHUD ACCUMULATE 1-2 INCHES OVR THE W AS IN GOING FCST. LESS THAN AN INCH ELSEWHERE. GOING TEMPS FCST NEEDS ONLY MINOR ADJUSTMENT. .MQT...WINTER STORM WATCH TONIGHT/FRIDAY MIZ001>007-009>014. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1010 AM EST THU FEB 8 2001 UPDATED ZONES FOR CURRENT RADAR TRENDS. HAVE KEPT WINTER STORM WARNING AND ADVISORIES IN EFFECT FOR SE COUNTIES... AND HAVE CANCELLED ADVISORIES AND WARNINGS ELSEWHERE...AS TRAILING EDGE OF PRECIPITATION MOVES ACROSS CENTRAL COUNTIES. RUC SHOWS UPPER SUPPORT FOR CONTINUING PRECIPITATION SHIFTS SLOWLY SOUTHWARD THIS AFTERNOON. .APX...WINTER STORM WARNING...THIS MORNING AND EARLY AFTERNOON... MIZ029-030-034>036 WINTER WEATHER ADVISORY...THIS MORNING AND EARLY AFTERNOON... MIZ041-042. WINTER STORM WATCH...TONIGHT AND FRIDAY...MIZ008>015. CAMPBELL mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 235 PM MST THU FEB 8 2001 ...SNOW ADVISORY ENTIRE FORECAST AREA TONIGHT... THANKS TO SURROUNDING OFFICES FOR CONFERENCE COORDINATION CALL PARTICIPATION. MAIN FORECAST CHALLENGE IS SNOWFALL AMOUNT TONIGHT...WITH TEMPERATURES AS SECONDARY CHALLENGE. INITIAL COLD FRONT MOVED THROUGH THE AREA LATE YESTERDAY AND INTO THE TEXAS PANHANDLE OVERNIGHT WITH FREEZING PRECIPITATION FOLLOWING IT SOUTH. A SECONDARY COLD FRONT IS FOLLOWING IT THROUGH EASTERN WYOMING AND WESTERN NEBRASKA TODAY WITH A CHANGE OVER TO SNOW ACROSS THE ENTIRE TRI-STATE AREA. 12Z MODELS WERE SIMILAR ALOFT WITH THE ETA PORTRAYING THE LOWER LEVELS BETTER FROM 00-06HRS. NGM/ETA WERE SIMILAR AND HAVE GONE WITH THE ETA DUE TO BETTER HANDLING OF THE COLDER SHALLOW AIRMASS. ALL MODELS ARE LIFTING THE SURFACE LOW THROUGH OKLAHOMA...SOUTHEAST KANSAS AND INTO MISSOURI BY FRIDAY MORNING WITH HIGH PRESSURE TO FOLLOW ON SATURDAY. THE UPPER TROUGH MOVES ACROSS WESTERN KANSAS BY FRIDAY MORNING WITH GOOD 700 AND 500MB OMEGAS MOVING ACROSS THE AREAS AHEAD OF THE WAVE. A S/WV RIDGE BUILDS IN BY SATURDAY MORNING WITH SUBSIDENCE AND CLEARING AS THE TROUGH MOVES QUICKLY EAST OF THE GREAT LAKES REGION. RUC...ETA...AND NGM ARE IN CLOSE AGREEMENT WITH SNOWFALL AMOUNTS OVERNIGHT RANGING BETWEEN 2 AND 6 INCHES. HAVE DECIDED ON A SNOW ADVISORY WITH 3-5 INCHES PRIMARILY OVER FAR NORTHEAST COLORADO AND SOUTHWEST NEBRASKA WITH 4-6 INCHES ELSEWHERE. PLENTY OF MOISTURE AND CONVECTIVE ACTIVITY UPSTREAM ARE LOOKING FAVORABLE FOR THE POSSIBILITY OF BANDED TYPE SNOWFALL AND SNOWFALL ENHANCEMENT...MAINLY IN SOUTHEASTERN SECTIONS. ECMWF AND MRF ARE IN GOOD AGREEMENT THROUGH THE EXTENDED PERIOD. CURRENT EXTENDED LOOKS ON TRACK...SO WILL NOT MAKE ANY BIG CHANGES. .GLD...SNOW ADVISORY TONIGHT...COLORADO ZONES...90...91...92... KANSAS ZONES...1>4...13>16...27>29...41...42... NEBRASKA ZONES...79...80...81. LOCKHART ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 220 PM CST THU FEB 8 2001 BREIF DISCUSSION THIS AFTN WITH WINTER WX ONGOING ATTM. HAVE DOWNGRADED WATCH IN THE EAST TO ADVISORIES THIS AFTN AND TONIGHT. AVN AND NEW RUC HINTING THAT JETS ACRS NRN US WILL NOT COUPLE UP TONIGHT...WITH PRIMARY PCPN OCCURING FARTHER SOUTH ALONG CONVERGENCE ZONE. UNSTABLE AIR SOUTH OF THIS BOUNDARY WILL FUEL TSTMS ALONG IT...WHICH WILL CUT OFF MOISTURE INFLUX FOR FCST AREA. THEREFORE...MOST PCPN ACRS MN FCST AREA WILL LIKELY OCCUR WITH CURRENT COUPLED JET PATTERN BEFORE 03Z. FAR ERN FCST AREA (EAU/RPD) MAY STILL HAVE A SHOT AT GETTING 4 TO 7 INCHES OF SNOW AS RIGHT ENTRANCE REGION OF ANTICYCLONIC JET STREAK REMAIN OVER THIS AREA THROUGH 06Z. NEW 18Z ETA SUPPORTS THIS AS WELL. STORY FOR LATE TONIGHT/FRIDAY WILL BE MUCH COLDER TEMPS AND GUSTY NW WINDS WILL ARCTIC HIGH BUILDING INTO THE REGION. SHOULD BE A GOOD DEAL OF BLOWING AND DRIFITNG IN OPEN AREAS TON/FRI MORNING. WRN MN WILL SEE WIND CHILLS OF 20 TO 40 BELOW BY FRIDAY MORNING. WILL GENERALLY UNDERCUT GUIDANCE FOR TEMPS AS WELL FRI/SAT. NO BIG CHANGES TO EXTENDED...WITH PACIFIC SYSTEM BRINGING NEXT CHANCE OF SNOW LATE IN THE WEEKEND. .MSP...WINTER WEATHER ADV THIS AFTN AND TONIGHT ENTIRE FCST AREA. DAVIS mn SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 249 PM CST THU FEB 8 2001 ...HEADLINES REMAIN PRIMARY CHALLENGE...AND SNOW AMOUNTS... IR AND WATER VAPOR IMAGERY FROM EARLY THIS AFTERNOON SHOWING THE DEFORMATION ZONE FINALLY TAKING SHAPE AS THE BIG UPPER LOW SPINS THROUGH ARIZONA. OVER EASTERN COLORADO...IR LOOP SHOWING CLOUD TOPS QUICKLY COOLING AND PUEBLO RADAR SHOWS LARGE AREA OF SNOW EXPANDING. IMPRESSIVE WARM CONVEYOR BELT FROM TEXAS INTO IOWA WITH CONVECTIVE RAIN/FREEZING RAIN...AND FRONTAL BOUNDARY SLOWLY MOVING THROUGH SE KANSAS. AREAS TO THE NORTH OF THE WARM CONVEYOR BELT HAVE ENDURED NEARLY 24 HOURS OF FREEZING DRIZZLE. RECENT CALLS FROM NORTH CENTRAL KANSAS INDICATE SOME PHASE CHANGE TO A SNOW/SLEET MIX. MODEL TRENDS CONTINUE WITH AVN THE SLOWEST AND MORE CUT OFF...ETA FASTER AND MORE OPEN...NGM BETWEEN. RUC MODEL VALID 06Z SUPPORTS MORE OF AN AVN SOLUTION...AS DOES THE WATER VAPOR IMAGERY. SYSTEM IS CERTAINLY ALREADY A CLOSED CIRCULATION IN THE WATER VAPOR LOOP...AND AS IT EJECTS OUT INTO THE PLAINS SEE NO REASON FOR IT TO FILL AS QUICK AS ETA SUGGESTS. THUS WILL CONTINUE TO LEAN TOWARDS AVN SOLUTION FOR TRACK OF THE UPPER WAVE...ALTHOUGH THE AVN MAY NOT HAVE THE BEST GRASP ON THE LOW/MID LEVEL THERMAL AND MOISTURE FIELDS. THE DEFORMATION ZONE PRECIPITATION APPEARS TO BE HANDLED WELL BY THE AVN 700-500 LAYER Q-S CONVERGENCE...WHICH MOVES DIRECTLY OVER MY NORTH CENTRAL KANSAS AND SOUTHEAST NEBRASKA COUNTIES OVERNIGHT TONIGHT AND INTO FRIDAY MORNING...WHICH IS IN LINE WITH THE SUGGESTED PRECIPITATION AREA FROM THE UPPER LOW TRACK/MODEL QPF. COUNTIES MORE NORTH AND WEST SHOULD ALSO CATCH SOME DEFORMATION ZONE SNOW...BUT NOT AS HEAVY. SOME CONCERN ABOUT HOW SHORT LIVED THE ISENTROPIC LIFT IS...GENERALLY ENDING OFF AFTER 06Z. HOWEVER STILL THINK THE DEFORMATION ZONE WILL BE FAIRLY ACTIVE...DESPITE THE LACK OF LOWER LEVEL ISENTROPIC LIFT. ALSO A BIT OF FRONTOGENETICAL FORCING FOUND ABOVE THE COLD DOME...MAINLY IN THE H7-H5 LAYER. THUS CURRENT ZONE BREAKUP LOOKS REASONABLE WITH HIGHER THREAT AREAS SOUTH AND EAST...BUT CONFIDENCE IS FAIR AT BEST. MIXING RATIO VALUES ON THE MESOETA 290K SURFACE FEEDING INTO MY SOUTHEAST COUNTIES INDICATE AS MUCH AS 9 G/KG. AND THE 24 HOUR ACCUMULATED PRECIP FROM BOTH THE AVN AND THE MESOETA ARE IN EXCELLENT AGREEMENT...WITH CLOSE TO 1 INCH FAR SOUTHEAST AND AROUND ONE-QUARTER INCH FAR NORTHWEST. THIS AIRMASS IS COLD ENOUGH FOR 15:1 SOUTH AND PERHAPS 20:1 NORTH. SOME HINT OF POTENTIAL FOR BRIEF CONVECTION OR CSI IN SOUTHEAST COUNTIES OVERNIGHT. SO IF ALL SNOW...MAX AMOUNT COULD BE APPROACHING 10-12 INCHES IN EXTREME SOUTHEAST CORNER. HOWEVER MODEL SOUNDINGS KEEP AN ELEVATED WARM LAYER INTO THE EVENING HOURS IN THE SOUTHEAST...SO SOME PRECIPITATION WILL FALL AS SLEET BEFORE DYNAMICAL COOLING AND A DEEPENING COLD AIRMASS CHANGE IT TO ALL SNOW. THIS WILL LIMIT SNOW ACCUMULATION ESPECIALLY SOUTHEAST. INITIAL THOUGHTS ON SNOW ACCUMULATIONS RANGE FROM 6-8 INCHES FAR SOUTHEAST TO 2-4 ORD/LXN... ENDING BY NOON FRIDAY. NEXT CONCERN IS THE WINDS...WHICH ARE A BIT CHALLENGING GIVEN THE LACK OF A DEFINED SURFACE LOW IN THIS COLD AIR. H85 CIRCULATION SHOULD BE SOMEWHERE OVER NRN MISSOURI FRIDAY...SO STRONG WINDS SEEM LIKELY OVER MOST OF THE CWA AT LEAST IN THE MORNING. HIGHEST GUSTS SHOULD BE NEAR 40 MPH...PLENTY FOR BLOWING AND DRIFTING SNOW PROBLEMS WITH THE FLUFFY SNOW/COLD AIR. WILL KEEP WINTER STORM WARNING IN PLACE AND ADD PHILLIPS AND ROOKS TO WARNING...AND CONVERT CURRENT WINTER WEATHER ADVISORY AREA TO A SNOW AND BLOWING SNOW ADVISORY. WILL ALSO EXTEND THE WARNING AND ADVISORY INTO FRIDAY WITH THE EXPECTED GUSTY WINDS AND MORNING SNOW. BEYOND FRIDAY...SHORTWAVE RIDGING BUILDS IN BEHIND THE EXITING LOW...BUT NEXT BIG TROF DIGS INTO WEST COAST AGAIN. MORE ISENTROPIC LIFT DEVELOPS OVER THE PLAINS SATURDAY NIGHT WITH A CHANCE FOR PRECIP ON SUNDAY. THIS MAIN SYSTEM IS THEN PROGGED TO MOVE INTO THE PLAINS WED/THU...WITH ANOTHER CHANCE FOR SNOW THEN. INTERESTING HOW THE MAIN NORTH AMERICAN POLAR LOW IS PROGGED BY EXTENDED MODELS TO SETTLE OVER THE HUDSON BAY...THEN DROP SLOWLY SOUTH BY FRIDAY. IF THIS HOLDS TRUE...MORE ARCTIC AIR IS IN STORE FOR THE END OF THE WEEK. GUIDANCE TEMPERATURES LOOKS TOO WARM ESPECIALLY FOR SATURDAY WITH A COLD START TO THE DAY...SNOW COVER...AND INCREASING MID/HIGH CLOUDS. LOWS LAST NIGHT WERE BELOW ZERO OVER MUCH OF WY/MT...AND EXPECT FRIDAY NIGHT LOWS TO DROP BELOW ZERO AT LEAST IN NEBRASKA...BELOW GUIDANCE. .GID...WINTER STORM WARNING TONIGHT AND FRIDAY FOR POLK...YORK...HAMILTON ...HALL...ADAMS...CLAY...FILLMORE...THAYER...NUCKOLLS...WEBSTER ....SMITH...JEWELL...MITCHELL...OSBORNE...ROOKS...PHILLIPS SNOW AND BLOWING SNOW ADVISORY TONIGHT AND FRIDAY FOR FOR FRANKLIN... FURNAS...GOSPER...HARLAN...KEARNEY...PHELPS...BUFFALO...DAWSON... GREELEY...HOWARD...MERRICK...NANCE...SHERMAN...VALLEY NIETFELD ne