EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OFFICE MELBOURNE FL 930 PM EST FRI FEB 25 2005 .DISCUSSION... WATER VAPOR AND IR SATELLITE LOOPS WITH RUC40 500MB HEIGHTS AND VORTICITY AND 500MB RAOBS OVERLAID WERE SHOWING A SHORT WAVE AND ITS ASSOCIATED VORTICITY MAXIMA WERE EXITING THE PENINSULA INTO THE ATLANTIC AND A SHORT WAVE RIDGE OVER THE GULF COAST STATES. LATEST MSAS SURFACE ANALYSIS AND METARS SHOWED THE FRONTAL BOUNDARY HAD MOVED SOUTH OF THE CWA WITH THE WINDS HAVING SHIFTED TO THE NORTH AND A THE LOW CENTERS THAT WERE IN THE EASTERN GULF HAD SHIFTED EAST OF THE SPACE AND TREASURE COASTS. INCREASING PRESSURE GRADIENT BETWEEN THE LOW AND HIGH PRESSURE BUILDING ACROSS SOUTHERN GA AND NORTHERN FL WAS PRODUCING INCREASING NORTHERLY WINDS OVER NORTHEAST FLORIDA COASTAL WATERS. STRONGEST CONVECTION OCCURRED OVER THE SOUTHERN CWA WHERE THE FRONT INTERACTED WITH THE LAKE OKEECHOBEE BREEZE BOUNDARY. LATEST RADAR LOOP WAS SHOWING THAT THE STORMS HAD MOVED INTO THE COASTAL WATERS AND WERE DISSIPATING WHILE SHOWERS ASSOCIATED WITH THE FRONTAL BOUNDARY CONTINUE TO MOVE WEST-EAST ACROSS THE SOUTHERN HALF OF THE PENINSULA. ALTHOUGH MID/UPPER LEVEL SUPPORT APPEARS TO BE PULLING AWAY FROM CENTRAL FLORIDA AS WELL AS THE FRONT SLIPPING FARTHER DOWN THE PENINSULA ...THERE WILL BE ENOUGH RESIDUAL MOISTURE AND WEAK LIFT DUE TO PROXIMITY OF THE FRONT TO KEEP ISOLATED SHOWERS MAINLY OVER THE SOUTHERN THIRD OF THE CWA FOR THE OVERNIGHT HOURS. NORTHERLY PRESSURE GRADIENT WILL RESULT IN STRONG GUSTY WINDS ALG THE IMMEDIATE COAST FROM BREVARD NORTHWARD. ISOLATED COASTAL SHOWERS MOVING SOUTHWARD MAY AFFECT VOLUSIA/BREVARD COUNTIES. OTHER SHOWERS CURRENTLY OVER NORTH LAKE COUNTY WILL DISSIPATE AS THEY PUSH SE. CURRENT GRIDS HAVE A GOOD HANDLE ON THE WINDS BUT WILL BE REMOVING FOG MENTION AS NORTH WINDS SHOULD KEEP BOUNDARY LAYER WELL MIXED BUT WITH LOW CLOUDS. .MARINE...SURGE OF NORTH WINDS HAS ENTERED OUR NORTHERN MARINE AREA...CAPE WIND TOWERS RIGHT ALONG THE COAST ARE REPORTING 20KTS AS WELL AS SGJ. AS A RESULT...WILL RAISE SMALL CRAFT ADV FOR THE NORTH LEG OVERNIGHT. && .MLB WATCHES/WARNINGS/ADVISORIES... ...SMALL CRAFT ADVISORY FLAGLER BEACH TO COCOA BEACH. && $$ WIMMER/KELLY fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 840 PM MST FRI FEB 25 2005 .UPDATE...UPDATED FORECAST WILL BE OUT SHORTLY TO REFLECT THE INCREASING CLOUDINESS MOVING RAPIDLY TOWARD THE AREA AT 50 MPH FROM THE SOUTHWEST. OTHER ADJUSTMENTS INCLUDE THE TEMP/DP HOURLY GRIDS AS WELL AS MIN TEMPS. AT 0345Z CLOUDINESS CONTINUES TO MOVE QUICKLY NORTHEAST FROM SOUTHWEST KANSAS. ETA HAS THE SPECS OF THIS AREA WELL FORECAST BUT LOADING THE ETA12 INTO THE GRIDS IS TOO HARSH WITH THE RUC SHOWING THE OVERALL PROGRESSION BETTER. DEWPOINTS CONTINUING A SLOW INCREASE WITHIN THE ABOVE MENTIONED CLOUDINESS AND THE RUC FOR NOW HAS A BETTER GRASP ON THE GRADIENT FROM NORTHWEST TO SOUTHEAST SO HAVE USED IT AS WELL. FOR TEMPERATURES...03Z MET GUIDANCE FIT NICELY WITH 03Z OBS SO HAVE FOLLOWED IT AND THE RUC FOR THE REST OF THE NIGHT. 5 DAY PERFORMANCE OF THE MAV/MET/FWC GUIDANCE FOR 1ST PERIOD MINS SHOWS VERY GOOD PERFORMANCE SO LITTLE CHANGE WAS NEEDED HERE. EXCEPTION WAS OVER THE FLAGLER AREA (FAR WESTERN KIT CARSON COUNTY) WHERE RIGHT NOW LIMON IS 20 DEGREES. LAST NIGHT THEY DROPPED INTO THE TEENS. I FOLLOWED THE MAV/MET GUIDANCE NUMBERS OUT THERE WHICH DROPS THEM QUITE A BIT FROM PREVIOUS FORECAST. THATS IT FOR NOW. && .GLD WATCHES/WARNINGS/ADVISORIES... .KS...NONE. .NE...NONE. .CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 930 PM EST FRI FEB 25 2005 .DISCUSSION... .SHORT TERM... 00Z RAOBS/WV IMAGERY AND RUC ANALYSIS SHOW HI AMPLITUDE WRN RDG/ERN TROF OVER NAMERICA HELD IN PLACE BY BLOCKING UPR HI OVER THE NATLANTIC. SHRTWV RDG NOTED OVER NW ONTARIO IN NW FLOW ALF OVER THE UPR GRT LKS BTWN WRN RDG/ERN TROF...12HR H5 HGT RISES OF 70M NOTED AT INL/YPL. 1030MB ARCTIC HI PRES NOTED OVER NW ONTARIO UNDER THE SHRTWV RDG. BOTH 00Z SDNGS SHOW SUBSIDENCE INVRNS AT H85 ABOVE DRY PBL AS EVIDENCED BY INVERTED V TEMP/TD PROFILES. EARLIER TAMDAR SDNG FM YQT SHOWED A SIMILARLY DRY PBL. DESPITE THE NLY FLOW OF COLD AIR (00Z H85 TEMPS -17C AT INL/-22C AT YPL) BTWN SFC HI PRES TO THE NW AND LO PRES OVER LK HURON...THIS DRY AIR AND RELATIVELY ACYC LLVL FLOW ASSOCIATED WITH RDG AXIS STRETCHING S FM THE HI CENTER TOWARD THE WRN U.P. HAS NEGATIVELY IMPACTED LES BANDS IN SHORTER FETCH OVER WRN LK SUP. IN FACT...THERE IS LTL IN THE WAY OF CLDS OVER WRN LK SUP AS FAR E AS THE KEWEENAW PENINSULA...WHERE SOME -SHSN ONGOING. LATEST STLT IMAGERY SHOWS NRMS WIND PARALLEL BANDS IN GREATEST CONCENTRATION OVER CNTRL LK SUP TO THE E OF SFC RDG AXIS AND WHERE FETCH LENGTH IS LONGER. BUT DRY AIR APPEARS TO BE REDUCING INTENSITY OF LES BANDS EVEN IN AREA FVRD BY THE OBSVD NLY FLOW AS MQT 88D INDICATES REFLECTIVITY RETURNS GENERALLY UNDER 20DBZ EVEN THOUGH MQT VWP HINTS AT INVRN HGT AT 6K FT MSL. DESPITE THIS APRNT NEGATIVE IMPACT...STLT IMAGERY INDICATES THE LES BANDS OVER CNTRL LK SUP ARE BECMG MORE WDSPRD/FATTER. OTRW... LINGERING DIURNAL CLDS HAVE CLRD OVER THE SCNTRL ZNS AND IN THE FAR W (WITH DOWNSLOPING ACYC NE FLOW AT IWD). MAIN FCST CONCERNS TNGT ARE LES TRENDS/TEMPS. LATEST RUC/ETA SHOW SFC HI PRES OVER NW ONTARIO DRIFTING SLOWLY E OVERNGT...WITH LLVL WINDS VEERING A BIT OVERNGT. LES WL CONT ALL NGT WITH A FLOW OF COLD AIR REMAINING. EXPECT THE GREATEST CONCENTRATION OF SHSN TO BE OVER AREAS FVRD BY NNE LLVL FLOW...ERN MQT/WRN ALGER COUNTY. HOWEVER...MAGNITUDE OF FCST LLVL CNVGC FCST IS MARGINAL AS LARGER SCALE ACYC FLOW/DRY AIR UNDER DNVA/H85-5 QVECTOR DVGC. EVEN THOUGH LES CHART WOULD SUG 3"/6 HRS WL ACCUMULATE...WL CUT DOWN FCST AMTS TO REFLECT IMPACT OF DRY AIR. BEST CHC FOR LOWEST TEMPS AOB ZERO WL WL BE OVER THE SCNTRL AND W IN AREAS OF DIFFLUENT/ DOWNSLOPING N-NE FLOW CLOSE TO SFC RDG AXIS. OVERALL...GOING FCST HAS GOOD HANDLE ON EXPECTED CONDITIONS AND NEEDS LTL CHG. KC .LONG TERM... SFC RIDGE WILL SLOWLY DRIFT E ACROSS UPPER MI/LAKE SUPERIOR SAT. EXPECT SOME LINGERING LIGHT LES ALONG NCNTRL COUNTIES IN MORNING UNTIL WINDS VEER E AND GENERALLY OFFSHORE IN THE AFTERNOON. INLAND...DAYTIME HEATING AGAIN LEAD TO SOME STRATOCU FORMATION AS NAM FCST SOUNDINGS SHOW STEEP LOW-LEVEL LAPSE RATES AGAIN. GOING FCST HIGH TEMPS OF UPPER TEENS TO LOW 20S STILL LOOK GOOD WITH A NOD TOWARD COOLER MAV GUIDANCE. SAT NIGHT...FOLLOWED BLEND OF MORE CONSISTENT UKMET...CANADIAN AND ETA SOLNS WHICH IS A BIT SLOWER THAN GFS WITH DEEPENING OF TROF INTO UPR GREAT LAKES. THUS...BACKED OFF A BIT ON TIMING OF CHC OF -S INTO FORECAST AREA...LIMITING CHC POPS TO MAINLY WEST HALF OF FA LATE. BELIEVE...DRY ERLY FLOW ON BACKSIDE OF RDG WILL DELAY TOP DOWN MOISTENING OF COLUMN PER WHAT ETA SNDGS SEEM TO BE INDICATING...DESPITE ONSET OF STRONGER 295K ISENTROPIC ASCENT LATE. SUN INTO SUN NIGHT...MID-UPR LVL TROF CONTINUES TO AMPLIFY INTO THE UPR GREAT LAKES WITH GOOD DEEP Q-VECT CONV AND MOISTURE SPREADING ACROSS FORECAST AREA FROM WEST TO EAST AND STRONG 295K ISENTROPIC LIFT ESPECIALLY INTO SCNTRL ZONES. NAM/CANADIAN/UKMET SHOW DEVELOPING SFC LOW OVER ERN MN BY 12Z MOVING INTO CNTRL WI BY 00Z MON. BELIEVE STRONG DYNAMICS WILL QUICKLY OVERCOME DRIER AIR AS LOW-LEVELS. WITH NAM/UKMET 285-290K SFCS SHOWING MIXING RATIOS OF 2-3G/KG AVAILABLE AND ETA/CANADIAN QPF AMOUNTS OF AROUND .25 TO .40 INCH. WOULD EXPECT 4-7 INCHES OF SNOW POSSIBLE OVER SOUTH CENTRAL COUNTIES GIVEN PROJECTED WATER/SNOW RATIO OF 15/1 WHERE BETTER 800-700 MB FRONTOGENETICAL WILL BE LOCATED. FURTHER NORTH AWAY FROM BEST LIFT EXPECT AMOUNTS MORE IN 2 TO 5 INCH RANGE. ENHANCEMENT POTENTIAL WITH SERLY FLOW OFF LAKE MI WILL FAVOR MNM AND DELTA COUNTIES FOR HIGHER SNOW AMTS OF 4-7 ESPECIALLY BY AFTERNOON. ETA BUFR SNDGS SHOW STRONG OMEGA VALUES INTERSECTING FAVORABLE SNOW GROWTH REGION AS WELL. LINGERING LIFT AND ENHANCEMENT POTENTIAL WILL KEEP HEAVIER SNOW GOING FOR DELTA AND MNM COUNTIES INTO SUN EVENING AS WELL. THUS..HAVE ISSUED WINTER STORM WATCH FOR IRON-DICKINSON FOR SUNDAY AND FOR DELTA-MNM COUNTIES FOR SUNDAY INTO SUNDAY EVENING. AS WINDS SHIFT MORE ENE ON BACKSIDE OF SFC TROF AXIS LATER SUNDAY NIGHT...HEAVIER SNOW POTENTIAL WILL SHIFT MORE INTO NCNTNL COUNTIES. MON-WED...THIS PERIOD AGAIN STILL LOOKS VERY FAVORABLE FOR A PROLONGED LAKE ENHANCED SNOW EVENT FOR N WIND FAVORED LOCATIONS...ESPECIALLY NCNTRL UPPER MI (BARAGA/MARQUETTE/WRN ALGER COUNTIES). MODELS STILL SHOW LITTLE MOVEMENT IN BROAD DEEP TROUGH WITH BLOCKING HIGH IN PLACE OVER GREENLAND. COMBINATION OF DEEP MOISTURE AND DEEP N TO NE CYCLONIC FLOW ALONG WITH AND 850MB TEMPS RUNNING AROUND -16C SHOULD LEAD TO POTENTIAL VERY HEAVY SNOW FOR A EXTENDED PERIOD...BEGINNING MON AND CONTINUING POSSIBLY INTO WED. THU-FRI...SNOW SHOULD TAPER OFF BY THU AS OPERATIONAL MODELS SHOW RDGG BUILDING IN FROM WEST 850 MB TEMPS REBOUNDING TO AROUND -12C. STILL IF ECMWF AND CANADIAN ENSEMBLE MEANS HOLD TRUE NW FLOW WILL STILL YIELD SOME LIGHT LES ESPECIALLY FOR NRN COUNTIES. MORE UNCERTAINTY ON FRI AS 12Z GFS SHOWS POTENTIAL FOR CLIPPER SYSTEM TO COME DOWN AND BRING ANOTHER SHOT OF COLDER 850 MB TEMPS SO WILL KEEP A CHC OF SNOW IN FOR ENTIRE CWA. VOSS && .MQT...WATCHES/WARNINGS/ADVISORIES... HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. WINTER STORM WATCH IN EFFECT SUNDAY MIZ010-011. WINTER STORM WATCH IN EFFECT SUNDAY INTO SUNDAY EVENING MIZ012-013. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 545 PM EST FRI FEB 25 2005 .DISCUSSION... MAIN FCST ISSUES ARE LINGERING LES AND MIN TEMPS TONIGHT...THEN SYNOPTIC SNOW SUN WITH POTENTIAL FOR MAJOR N WIND LAKE ENHANCED SNOW EVENT EARLY NEXT WEEK. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW CONTINUING OVER WRN NAMERICA WITH STRONG RIDGE FROM THE NRN U.S. ROCKIES INTO CANADA AND SRN STREAM UNDERCUTTING RIDGE INTO SW CONUS. POLAR VORTEX IS OVER HUDSON BAY WITH BLOCKING HIGH OVER GREENLAND. AS A RESULT...NW FLOW CONTINUES INTO THE UPR GREAT LAKES/MIDWEST. CLIPPER SHORTWAVE OVER NRN ALBERTA IS DUE TO DIG SOUTHEAST BRINGING AMPLIFIED TROF INTO THE UPR GREAT LAKES. VISIBLE SATELLITE AND MQT RADAR INDICATES GENERALLY WEAK LES BANDS INTO NCNTRL U.P. WITH A NRLY FLOW AHEAD OF BUILDING CANADIAN RDG. A FEW STRONGER RETURNS OF 20 DBZ OR HIGHER NOTED OVER ERN MQT AND WRN ALGER COUNTIES. MODELS STILL ADVERTISE SFC HIGH AXIS BUILDING SOUTH FROM ONTARIO INTO WRN UPR MI OVERNIGHT. ASSOC DRYING/SUBSIDENCE SHOULD PROVIDE FOR SOME CLRG OVER WRN COUNTIES. HOWEVER SUSPECT INSTABILITY OVER ERN LAKE SUPERIOR WITH TEMPS -18 TO -20C RANGE TO KEEP LES GOING INTO NCNTRL COUNTIES. ALTHOUGH ETA BUFR SNDGS SHOW INVERSION HGTS LOWER TO AROUND 4KFT LATER THIS EVENING...INCREASING LVLL CONVERGENCE WITH LAND BREEZE COMPONENT TO WIND WILL INTO FAVOR ERN MQT AND WRN ALGER FOR SOME POSSIBLE HEAVIER LES BANDS. LOCAL GUIDANCE 1 TO LOCALLY 3 INCH AMOUNTS POSSIBLE OVER THESE COUNTIES TONIGHT. INLAND AREAS WITH CLEARING SHOULD REACH AS LOW AS -5F UNDER SFC RDG...SIMILAR TO LAST NIGHT' READINGS UPSTREAM UNDER THE RDG AXIS. SFC RIDGE WILL SLOWLY DRIFT E ACROSS UPPER MI/LAKE SUPERIOR SAT. EXPECT SOME LINGERING LIGHT LES ALONG NCNTRL COUNTIES IN MORNING UNTIL WINDS VEER E AND GENERALLY OFFSHORE IN THE AFTERNOON. INLAND...DAYTIME HEATING AGAIN LEAD TO SOME STRATOCU FORMATION AS NAM FCST SOUNDINGS SHOW STEEP LOW-LEVEL LAPSE RATES AGAIN. GOING FCST HIGH TEMPS OF UPPER TEENS TO LOW 20S STILL LOOK GOOD WITH A NOD TOWARD COOLER MAV GUIDANCE. SAT NIGHT...FOLLOWED BLEND OF MORE CONSISTENT UKMET...CANADIAN AND ETA SOLNS WHICH IS A BIT SLOWER THAN GFS WITH DEEPENING OF TROF INTO UPR GREAT LAKES. THUS...BACKED OFF A BIT ON TIMING OF CHC OF -S INTO FORECAST AREA...LIMITING CHC POPS TO MAINLY WEST HALF OF FA LATE. BELIEVE...DRY ERLY FLOW ON BACKSIDE OF RDG WILL DELAY TOP DOWN MOISTENING OF COLUMN PER WHAT ETA SNDGS SEEM TO BE INDICATING...DESPITE ONSET OF STRONGER 295K ISENTROPIC ASCENT LATE. SUN INTO SUN NIGHT...MID-UPR LVL TROF CONTINUES TO AMPLIFY INTO THE UPR GREAT LAKES WITH GOOD DEEP Q-VECT CONV AND MOISTURE SPREADING ACROSS FORECAST AREA FROM WEST TO EAST AND STRONG 295K ISENTROPIC LIFT ESPECIALLY INTO SCNTRL ZONES. NAM/CANADIAN/UKMET SHOW DEVELOPING SFC LOW OVER ERN MN BY 12Z MOVING INTO CNTRL WI BY 00Z MON. BELIEVE STRONG DYNAMICS WILL QUICKLY OVERCOME DRIER AIR AS LOW-LEVELS. WITH NAM/UKMET 285-290K SFCS SHOWING MIXING RATIOS OF 2-3G/KG AVAILABLE AND ETA/CANADIAN QPF AMOUNTS OF AROUND .25 TO .40 INCH. WOULD EXPECT 4-7 INCHES OF SNOW POSSIBLE OVER SOUTH CENTRAL COUNTIES GIVEN PROJECTED WATER/SNOW RATIO OF 15/1 WHERE BETTER 800-700 MB FRONTOGENETICAL WILL BE LOCATED. FURTHER NORTH AWAY FROM BEST LIFT EXPECT AMOUNTS MORE IN 2 TO 5 INCH RANGE. ENHANCEMENT POTENTIAL WITH SERLY FLOW OFF LAKE MI WILL FAVOR MNM AND DELTA COUNTIES FOR HIGHER SNOW AMTS OF 4-7 ESPECIALLY BY AFTERNOON. ETA BUFR SNDGS SHOW STRONG OMEGA VALUES INTERSECTING FAVORABLE SNOW GROWTH REGION AS WELL. LINGERING LIFT AND ENHANCEMENT POTENTIAL WILL KEEP HEAVIER SNOW GOING FOR DELTA AND MNM COUNTIES INTO SUN EVENING AS WELL. THUS..HAVE ISSUED WINTER STORM WATCH FOR IRON-DICKINSON FOR SUNDAY AND FOR DELTA-MNM COUNTIES FOR SUNDAY INTO SUNDAY EVENING. AS WINDS SHIFT MORE ENE ON BACKSIDE OF SFC TROF AXIS LATER SUNDAY NIGHT...HEAVIER SNOW POTENTIAL WILL SHIFT MORE INTO NCNTNL COUNTIES. MON-WED...THIS PERIOD AGAIN STILL LOOKS VERY FAVORABLE FOR A PROLONGED LAKE ENHANCED SNOW EVENT FOR N WIND FAVORED LOCATIONS...ESPECIALLY NCNTRL UPPER MI (BARAGA/MARQUETTE/WRN ALGER COUNTIES). MODELS STILL SHOW LITTLE MOVEMENT IN BROAD DEEP TROUGH WITH BLOCKING HIGH IN PLACE OVER GREENLAND. COMBINATION OF DEEP MOISTURE AND DEEP N TO NE CYCLONIC FLOW ALONG WITH AND 850MB TEMPS RUNNING AROUND -16C SHOULD LEAD TO POTENTIAL VERY HEAVY SNOW FOR A EXTENDED PERIOD...BEGINNING MON AND CONTINUING POSSIBLY INTO WED. THU-FRI...SNOW SHOULD TAPER OFF BY THU AS OPERATIONAL MODELS SHOW RDGG BUILDING IN FROM WEST 850 MB TEMPS REBOUNDING TO AROUND -12C. STILL IF ECMWF AND CANADIAN ENSEMBLE MEANS HOLD TRUE NW FLOW WILL STILL YIELD SOME LIGHT LES ESPECIALLY FOR NRN COUNTIES. MORE UNCERTAINTY ON FRI AS 12Z GFS SHOWS POTENTIAL FOR CLIPPER SYSTEM TO COME DOWN AND BRING ANOTHER SHOT OF COLDER 850 MB TEMPS SO WILL KEEP A CHC OF SNOW IN FOR ENTIRE CWA. && .MQT...WATCHES/WARNINGS/ADVISORIES... HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. WINTER STORM WATCH IN EFFECT SUNDAY MIZ010-011. WINTER STORM WATCH IN EFFECT SUNDAY INTO SUNDAY EVENING MIZ012-013. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1240 PM EST FRI FEB 25 2005 .AVIATION... MAINLY IFR CONDITIONS WILL PREVAIL THROUGH THE REMAINDER OF THE AFTERNOON AND TONIGHT. SHORT WAVE TROF AND SURFACE FRONT WILL PROGRESS EAST OF THE REGION THIS EVENING AS WINDS BEGIN TO VEER TO THE NORTHWEST. HOWEVER, WHILE THE LIFT WILL SUBSIDE ALONG WITH THE SNOW...BORDERLINE IFR/MVFR CEILINGS PREVAIL OVERNIGHT WITH QUICKLY IMPROVING CONDITIONS SHORTLY AFTER 12Z SATURDAY. BGM && .UPDATE... ISSUED AT 1100 AM EST SHORT WAVE TROF AND ASSOCIATED SURFACE COLD FRONT CONTINUES TO ADVANCE EAST WITH OCCASIONAL LIGHT SNOW. WHILE LATEST RADAR RETURNS ARE DECREASING ACROSS THE CWA, UPSTREAM WE ARE OBSERVING AN INCREASE IN THE SNOWFALL. THIS IS LIKELY DUE TO LAKE MICHIGAN INTERACTION AND AIDED BY 100KT 300MB EXIT REGION TO ENHANCE LIFT. LATEST RUC HAS AN EXCELLENT HANDLE ON THESE FEATURES SO WE WILL CONTINUE WITH THE CURRENT FORECAST...JUST REFRESH THE ZFP TO REMOVE MORNING TIME REFERENCES. PLENTY OF IN-HOUSE DISCUSSIONS ABOUT THE NEXT SYSTEM FOR EARLY NEXT WEEK. TRENDS CONTINUE WITH A FURTHER WEST TRACK AS SHORT WAVE DIVES SOUTH ACROSS THE DAKOTAS AND TRYING TO PHASE WITH RESIDUAL ENERGY FROM PACIFIC SYSTEM INTO THE CENTRAL PLAINS. WE WILL AWAIT FOR THE ENSEMBLES AND LOCALLY PRODUCED WRFXX BEFORE MAKING CHANGES TO OUR CURRENT HWO. BGM && .SHORT TERM...TODAY AND TONIGHT (ISSUED AT 300 AM EST) PRETTY NICE AREA OF SNOWFALL HAS DEVELOPED WITH DISTURBANCE DROPPING SOUTHEAST THROUGH THE LAKES REGION...WITH UPSTREAM VISIBILITIES IN THE 1 TO 2 MILE RANGE PREVALENT FROM WISCONSIN...NOW INTO PORTIONS OF LOWER MICHIGAN. MODELS IN GOOD AGREEMENT IN THIS VORTICITY CENTER ACROSS THE AREA...WITH ASSOCIATED QPF VALUES IN THE 0.10-0.15 RANGE. GIVEN H85 TEMPERATURES AVERAGING -10C OR SO...AND SURFACE TEMPERATURES STARTING OUT IN THE TEENS TO AROUND 20...LIQUID/SNOW RATIOS SHOULD ALLOW LOCAL AMOUNTS OF 2 INCHES OR JUST A BIT BETTER. THIS AREA OF SNOW WILL OVERSPREAD THE REGION QUICKLY THIS MORNING...AND WILL ONLY DELAY THE ARRIVAL OF CATEGORICAL SNOWFALL (80%) IN THE FAR SOUTH. THIS SNOW WILL PERSIST MUCH OF THE DAY...STARTING WITH ISENTROPIC LIFT SNOWS THIS MORNING...FOLLOWED BY AFTERNOON SNOW ASSOCIATED WITH THE VORTICITY CENTER ITSELF. THIS TO WORK OUT OF THE REGION THIS EVENING...WITH COLD OVERNIGHT LOW TEMPERATURES TONIGHT. CURRENT FORECAST IS AT TO JUST BELOW GUIDANCE VALUES AND THIS SEEMS PRETTY REASONABLE. MAY EDGE THEM DOWN JUST A DEGREE OR TWO MORE IN ANTICIPATION OF ANOTHER INCH OR TWO OF FRESH POWDER...AND AT LEAST SOME DEGREE OF CLEARING IN BEHIND THIS SYSTEM. OVERALL...THOUGH...TONIGHT/S FORECAST IS IN GOOD SHAPE. && .LONG TERM... BELOW NORMAL TEMPERATURES TO CONTINUE FOR THE FORESEEABLE FUTURE. A GOOD SHOT OF COLD AIR TO ARRIVE BY SATURDAY AS STRONG CANADIAN HIGH SETTLES OVER THE CENTRAL GREAT LAKES. WITH THE HIGH CENTERED OVER LOWER MICHIGAN ON SATURDAY...IT WILL BE INTERESTING TO SEE HOW WARM IT GETS WITH THE LATE FEBRUARY SUNSHINE. THE AIRMASS IS LOOKING VERY COLD...AS 850 MB TEMPS ARE PROGGED TO RANGE FROM -12 C SOUTH TO -16 C NORTH. WITH A GOOD DEAL OF SUNSHINE...GOING FOR MAXES IN THE 25 TO 30 DEGREE RANGE. IF CONSIDERABLE DIURNAL CLOUDS DEVELOP BY LATE MORNING...WILL BE LOOKING AT MAXES MORE IN THE 20 TO 25 DEGREE RANGE. SURFACE HIGH REMAINS OVER SOUTHEAST MICHIGAN INTO THE EVENING HOURS...WHICH SHOULD ASSURE A QUICK DROP IN TEMPERATURES. WARM ADVECTION MID/HIGH CLOUDS EXPECTED TO FILTER INTO THE REGION AFTER MIDNIGHT. EVEN SO...EXPECTING MINS TO DROP INTO THE SINGLE NUMBERS OUTSIDE OF THE CITY...PER ETA MOS. THE USUAL SUSPECTS/GOOD RADIATORS (PHN/BAX) HAVE A SHOT AT DROPPING BELOW ZERO. LATEST WATER VAPOR IMAGERY INDICATING AN IMPRESSIVE UPPER LEVEL RIDGE CENTERED OVER THE NORTHERN ROCKIES. THIS RIDGE WILL MORE OR LESS HOLD FIRM THROUGH EARLY NEXT WEEK. POTENT SHORTWAVE JUST OFF THE WESTERN CANADIAN COAST TO RIDE OVER THE TOP OF THE RIDGE TODAY...AND THEN AMPLIFY THROUGH THE WEEKEND (WITH THE HELP OF A FEW NORTHERN STREAM SHORTWAVES DIVING SOUTH)...WITH AN EVENTUAL CUTOFF UPPER LEVEL LOW DEVELOPING OVER THE GREAT LAKES REGION EARLY NEXT WEEK...PER 00Z CANADIAN/GFS. MODEL DIFFERENCES ON JUST HOW FAST THIS EVOLVES...AND WHEN PHASING OCCURS WITH THE ACTIVE SOUTHERN STREAM. REGARDLESS...THERE APPEARS TO BE A HIGH PROBABILITY A STRONG LOW PRESSURE SYSTEM WILL SPIN UP ALONG THE EAST COAST. THE QUESTION IS...WILL THERE BE ANY MOISTURE TRANSPORT INTO THE CENTRAL GREAT LAKES AS THE COASTAL BOMB TAKES OVER. A LOOK AT THE 00Z EUROPEAN REVEALS A INTENSE LOW PRESSURE SYSTEM NEAR THE SOUTHERN NEW ENGLAND BENCHMARK (40N/70W) ON MONDAY...MORE IN LINE WITH 00Z NOGAPS AND CANADIAN MODELS. MEANWHILE...00Z GFS IS MUCH FATHER WEST WITH THE SURFACE LOW...TRACKING THROUGH EASTERN NEW YORK. WHEN...WHERE...AND HOW FAST THIS COASTAL DEVELOPMENT OCCURS WILL HAVE AN IMPACT ON HOW MUCH SNOW WE SEE...ASSUMING THE 500 MB LOW IS OVER OR JUST WEST OF THE REGION. OTHERWISE...YOU CAN PRETTY MUCH FORGOT ABOUT SEEING ANY SIGNIFICANT SNOW. FOR CONTINUITY...AND THE FACT I AM NOT READY TO PUT MUCH STOCK IN ANY PARTICULAR MODEL YET...WILL CONTINUE TO MENTION THE POSSIBILITY FOR A COUPLE OF INCHES OF SNOW ON MONDAY. WILL REMOVE THE MENTION OF RAIN...AS IT APPEARS THE WARM AIR WILL PINCH OFF AS THE NORTHERN STREAM WAVE DEEPENS AND HEIGHTS FALL OVER THE GREAT LAKES. COLD TEMPERATURES TO CONTINUE THROUGH THE REST OF THE FORECAST PERIOD AS THE COLD UPPER LOW OVER THE GREAT LAKES REGION/EASTERN CANADA IS SLOW TO PUSH OFF TO THE EAST (IF AT ALL). && .AVIATION... SCATTERED TO BROKEN VFR STRATOCU WORKING BACK INTO THE REGION AHEAD OF NEXT SYSTEM AS SURFACE RIDGE AXIS CONTINUES TO SLIP OFF TO THE EAST. DO NOT ANTICIPATE ANY LOWERING OF THIS CLOUD FIELD UNTIL STRONGER OVER RUNNING DEVELOPS IN ADVANCE OF WAVE OVER THE UPPER MISSISSIPPI VALLEY. BASED ON CURRENT SATELLITE AND RADAR TRENDS LOOKS LIKE CLOUD DECK SHOULD LOWER TO MVFR AROUND 09Z NORTH TO AROUND 11-12 IN THE DTW AREA. GOOD SHOT OF OVER RUNNING TO MOVE INTO THE ENTIRE CWA BY 12Z...WITH ADDITIONAL SYNOPTIC LIFT WITH FIRST IN A SERIES OF UPPER WAVES MOVING INTO THE REGION AS WELL. SO EVEN WITH A FAIRLY DRY SOUNDING AT 00Z...EXPECT FAIRLY QUICK SATURATION AND MVFR VSBYS IN SNOW SPREADING ACROSS THE SAGINAW VALLEY AFTER 09Z AND INTO THE DTW AREA AROUND 12Z. BEST SNOWFALL/SYNOPTIC LIFT APPEARS TO BE BEFORE 18Z...LINGERING TO AROUND 21Z IN THE DTW AREA...THEN MID LEVELS BEGIN TO DRY OUT. WEAK CYCLONIC FLOW IN WAKE OF ASSOCIATED COLD FRONT AND LIMITED MOISTURE AFTER 21-00Z...SO MAINLY JUST FLURRIES FOR THE EVENING HOURS WITH MVFR CIGS CONTINUING. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...NONE. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ DG/SF mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1115 AM EST FRI FEB 25 2005 .DISCUSSION... SNOW TRENDS FOR AFTN IS AGAIN MAIN CONCERN NORTHWEST FLOW ALOFT WITH PRIMARY SHORTWAVE PASSING TO E AND A WEAKER SHORTWAVE GRAZING N LK SUPERIOR. GENERALLY THIS SETUP HAS BEEN CASE LAST FEW DAYS. A COUPLE OF MAJOR DIFFERENCES TODAY THOUGH IN THE SFC PATTERN AS HIGH PRESSURE THAT HAS HAD GRIP ON REGION FOR MOST OF THE WEEK HAS GIVEN WAY TO ELONGATED AREA OF LOW PRES FM JAMES BAY INTO N LK MI AND EXTENDING INTO S IA. ANOTHER TROUGH AXIS WITH MUCH COLDER AIR IN ITS WAKE BISECTS KEWEENAW PENINSULA AND LK SUPERIOR WITH SFC TEMPS UPSTREAM OF LK SUPERIOR IN THE SINGLE DIGITS DESPITE SUNSHINE. VIS SAT SHOWS MAJORITY OF LAKE CLOUDS RUNNING OUT AHEAD OF THE LAKE TROUGH WITH NNE-SSW WIND PARELLEL BANDS SETTING UP OVR N HALF OF LK IN WAKE OF THE TROUGH. A LOT OF CAVEOTS IN THIS FCST BUT WILL BASICALLY KEEP GOING FLAVOR OF GRIDS/ZFP. LAKE TROUGH WILL BEGIN TO AFFECT N ZONES OTHER THAN KEWEENAW BY 18Z...ALREADY STARTING TO SNOW AT IWD AND ONTONAGON. DEVELOPING NE FLOW THORUGH H9 AND N FLOW AT H85 ALONG WITH H85 TEMPS COOLING TOWARD -16C BY LATE AFTN IS FAVORABLE FOR INCREASING LK EFFECT. CONCERN IS CURRENT INSTABILITY IN LWR LAYERS MAY ALLOW FOR SNOW SHOWERS ALONG INCOMING TROUGH TO FALL HEAVY AT LEAST BRIEFLY. 1000-850MB LAPSE RATES BTWN 8.0-9.0C/KM AND SB CAPES THROUGH H8 AROUND 50J/KG ARE FAVORABLE FOR ENHANCEMENT TO THE SNOW SHOWERS...NOT JUST ALONG LK SUPERIOR BUT AHEAD OF THE TROUGH INLAND AS WELL. IN FACT...HIGHEST LOWER LEVEL LAPSE RATES IN THE 1000-850MB LAYER ARE PRESENT FM IMT-ESC-ISQ BY MID AFTN. CONVECTIVE TEMPS IN THE MID 20S SUPPORT CU DEVELOPMENT BY AROUND 18Z ESPECIALLY SEEING HOW QUICK TEMPS ARE RISING THIS MORNING AFTER CHILLY OVERNIGHT LOWS. CHANGES WERE PRETTY MINOR...BUT DID ADD POSSIBILITY OF HEAVIER BURSTS OF SNOW AND TWEAKED TEMPS. UPDATED/PUBLISHED GRIDS OUT. TEXT ZFPMQT UPDATED SOON. && .PREV DISCUSSION (ISSUED AT 419 AM EST THIS MORNING)... MAIN FCST ISSUES ARE LES TONIGHT...MIN TEMPS TONIGHT...SYNOPTIC SNOW SUN AND THEN POTENTIAL FOR MAJOR N WIND LAKE ENHANCED SNOW EVENT EARLY NEXT WEEK. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW OVER WRN NAMERICA WITH STRONG RIDGE FROM THE NRN U.S. ROCKIES INTO CANADA AND SRN STREAM UNDERCUTTING RIDGE OVER THE FAR SW CONUS. POLAR VORTEX IS OVER HUDSON BAY...UPSTREAM OF MASSIVE CLOSED HIGH OVER ICELAND/GREENLAND (NEGATIVE NAO PATTERN). IN THE RESULTING NW FLOW INTO THE GREAT LAKES/MIDWEST...ONE SHORTWAVE WAS DIVING SE THRU MN INTO WI WITH ASSOCIATED AREA OF LIGHT SNOW FOR THE MOST PART PASSING JUST SW AND S OF UPPER MI. ANOTHER SHORTWAVE WAS LOCATED W OF JAMES BAY. SOME LES IS NOTED ON KMQT RADAR IMAGERY OVER ERN LAKE SUPERIOR IN LIGHT WRLY FLOW. SATELITTE IMAGERY SUGGESTS THERE MAY BE A SINGLE DOMINANT LES BAND OVER WRN LAKE SUPERIOR. SHORTWAVE OVER MN/WI WILL CONTINUE SE THIS MORNING WHILE SHORTWAVE W OF JAMES BAY ALSO ROTATES SE. END RESULT WILL BE A DEVELOPING NRLY LOW-LEVEL FLOW TODAY AS HIGH PRES BUILDS OVER WRN ONTARIO IN THE WAKE OF THE SHORTWAVES. UPSTREAM 00Z SOUNDING AT KINL SHOWED A MOIST PROFILE FROM ABOUT 875MB UP...ABOVE A WELL MIXED LAYER (A NEGATIVE FACTOR FOR LES). 850MB TEMP WAS -12C. AT CWPL...00Z SOUNDING REVEALED A MUCH DRIER COLUMN AND A DEEPER WELL MIXED LAYER EXTENDING TO ALMOST 800MB. 850MB TEMP WAS MUCH LOWER AT -21C. NAM/GFS FCST SOUNDINGS LOOK REASONABLE FOR TODAY...SHOWING A DEEP MOIST COLUMN SIMILAR TO OBSERVED 00Z KINL SOUNDING BUT WITH COLUMN THEN DRYING DURING THE AFTN IN LINE WITH CWPL SOUNDING. AT THE LOW-LEVELS...GFS AND NGM SHOW NRLY WINDS ACROSS LAKE SUPERIOR BY 12Z THIS MORNING. NAM/RUC13 SHOW WIND SHIFT REACHING KEWEENAW BY 12Z BUT NOT CLEARING THE REMAINDER OF THE LAKE SUPERIOR COUNTIES UNTIL MID AFTN. WSETA IS EVEN LATER IN THE MID/LATE AFTN. GIVEN OBSERVED CONDITIONS ON AND AROUND LAKE SUPERIOR ATTM...APPEARS NAM/RUC13 PROBABLY HAVE THE RIGHT IDEA. ALTHOUGH WINDS ARE FAIRLY LIGHT...SHARP DIRECTIONAL CONVERGENCE MAY LEAD TO A BAND OF MDT/HVY SNOW ALONG WIND SHIFT AS IT MOVES ONSHORE THRU THE DAY...SUPPORTED BY DEEP MOISTURE PROFILE AND ADEQUATE OVERWATER INSTABILITY. PASSAGE DURING THE AFTN WHEN DAYTIME HEATING WILL BE AT ITS PEAK TO DISRUPT LES PROCESSSES WILL KEEP SNOW FROM GETTING TOO HEAVY. NONETHELESS...THERE MAY BE A QUICK INCH OR TWO...MAYBE 3...OF ACCUMULATION AS IT PASSES. INLAND...STEEP LOW-LEVEL LAPSE RATES AGAIN TODAY IN THE PRESENCE OF MOIST LOW-MID LEVELS WILL PROMOTE INSTABILITY SHSN AHEAD OF APPROACHING SFC TROF. DRYING/SUBSIDENCE TAKE OVER TONIGHT WHILE SFC HIGH PRES BUILDS SE... WITH RIDGE EXTENDING S ACROSS WRN LAKE SUPERIOR BY 12Z SAT. THERE WILL BE PLENTY OF INSTABILITY FOR LES AS 850MB TEMPS WILL BE IN THE -18 TO -20C RANGE. HOWEVER...SUBSIDENCE/DRYING WILL ENSURE LES WILL REMAIN ON THE LIGHT SIDE DESPITE INSTABILITY...AND BANDS SHOULD BE FAIRLY WELL SEPARATED DUE TO THE DRY AIR. BETTER LES COVERAGE WILL BE OVER THE NCNTRL WITH FLOW MORE CONVERGENT DUE TO LAND BREEZE COMPONENTS TO WIND. FLOW OVER WRN SUPERIOR ACTUALLY VEERS NE OVER NIGHT WITH ARRIVAL OF RIDGE...SO LES MAY END OVER ALL BUT SHORELINE AREAS NEAR/AFTER MIDNIGHT. WILL GO WITH ACCUMULATIONS AROUND AN INCH W AND 1-2 NCNTL. INLAND AREAS...ESPECIALLY SW INTERIOR SHOULD GET QUITE COLD WITH EXPECTED CLEARING SKIES AND LIGHT/CALM WIND. HAVE GONE SEVERAL DEGREES BELOW GUIDANCE WITH MINS AS LOW AS -5F. SFC RIDGE WILL SLOWLY DRIFT E ACROSS UPPER MI/LAKE SUPERIOR SAT. WITH AIRMASS PLENTY COLD ENOUGH TO SUPPORT LINGERING LIGHT LES... WILL NEED TO CARRY SHSN NEAR THE LAKE UNTIL WINDS VEER SE AND OFFSHORE. INLAND...DAYTIME HEATING WILL LEAD TO SOME STRATOCU FORMATION...ESPECIALLY CNTRL/E...AS NAM FCST SOUNDINGS SHOW STEEP LOW-LEVEL LAPSE RATES AGAIN. HAVE CUT MAX TEMPS A FEW DEGREES WITH CHILLY AIRMASS OVER THE AREA TO START THE DAY. SAT NIGHT/SUN...ATTENTION TURNS TO THE BEGINNING OF WHAT WILL BE SHARP AMPLIFICATION OF TROF OVER THE GREAT LAKES. NAM/GFS/UKMET ARE VERY SIMILAR WITH MIDLEVEL TROF AXIS INTO ERN DAKOTAS/WRN MN BY 12Z SUN WITH DEVELOPING SFC LOW OVER ERN MN. CANADIAN GLOBAL IS BIT SLOWER WITH SFC LOW OVER WRN MN. GFS IS MOST AGGRESSIVE WITH PCPN... BRINGING IT ACROSS ENTIRE FCST AREA SAT NIGHT. UKMET/NAM ARE NOT FAR BEHIND WHILE CANADIAN HAS PCPN JUST ENTERING WRN UPPER MI AT 12Z SUN. WILL FAVOR THE SLOWER SOLUTIONS SINCE RECENT GFS RUNS HAVE BEEN INCONSISTENT ON TIMING/PLACEMENT AND DEGREE OF NRN STREAM AMPLIFICATION. THE ECMWF AND CANADIAN HAVE ALSO SHOWN GOOD CONSISTENCY ON A SLOWER SOLUTION OVER THE WEEKEND. SO...WILL BRING -SN CHC ACROSS ABOUT THE W HALF OF FCST AREA SAT NIGHT. GOING FCST OF SNOW LIKELY IS ON TRACK FOR SUN. NAM/GFS 285-290K SFCS SHOW MIXING RATIOS OF 2-3G/KG AVAILABLE WHICH WOULD TRANSLATE TO 4-6 INCHES OF SNOW DURING THE DAY SUN. THIS IS A BIT HIGHER THAN GFS/NAM MODEL QPF SUGGEST. IN ANYCASE...LOOKS LIKE A GENERAL 3-6 INCH SNOW FOR SUN WITH THE HIGHER AMOUNTS FROM SCNTRL INTO ERN UPPER MI WHERE BETTER LOW-LEVEL FRONTOGENETICAL FORCING WILL LINE UP. WILL LIKELY BE AN ADVY EVENT FOR THE S AND PERHAPS ELSEWHERE. MON-WED...THIS PERIOD MAY SHAPE UP TO PRODUCE A VERY IMPRESSIVE LAKE ENHANCED SNOW EVENT FOR N WIND FAVORED LOCATIONS...ESPECIALLY NCNTRL UPPER MI (BARAGA/MARQUETTE/WRN ALGER COUNTIES). GFS HAS COME BACK TOWARD SOME OF ITS PREVIOUS RUNS WITH MID/UPPER LOW CLOSING OFF MORE TO THE W IN THE GREAT LAKES...SIMILAR TO THE ECMWF AND CANADIAN MODELS WHICH HAVE SHOWN GOOD CONSISTENCY. COMBINATION OF DEEP MOISTURE/DEEP N TO NE CYCLONIC FLOW AND 850MB TEMPS RUNNING AROUND -15C SHOULD LEAD TO VERY HEAVY SNOW FOR A POTENTIALLY EXTENDED PERIOD...BEGINNING MON AND CONTINUING THRU TUE...AND POSSIBLY INTO WED PER 00Z CANADIAN GLOBAL. IF ECMWF/CANADIAN SOLUTIONS ARE ON THE RIGHT TRACK...THIS WILL VERY EASILY BE THE BIGGEST EVENT OF THE SEASON FOR NCNTRL UPPER MI. TOTALS MIGHT JUST RIVAL SOME OF THE BIGGER EVENTS IN THE RECORD BOOK IF THE CANADIAN SOLUTION IS RIGHT WITH A LONG DURATION EVENT OCCURRING THRU WED. THAT SEEMS TO BE THE LEAST LIKELY SOLUTION AT THE MOMENT THOUGH. INLAND AREAS SHOULD SEE AREAS OF LIGHT SNOW THRU THE PERIOD WITH SOME LIGHT ACCUMULATION. && .MQT...WATCHES/WARNINGS/ADVISORIES... HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. && $$ DISCUSSION...JLA PREV DISCUSSION...ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1100 AM EST FRI FEB 25 2005 .UPDATE... SHORT WAVE TROF AND ASSOCIATED SURFACE COLD FRONT CONTINUES TO ADVANCE EAST WITH OCCASIONAL LIGHT SNOW. WHILE LATEST RADAR RETURNS ARE DECREASING ACROSS THE CWA, UPSTREAM WE ARE OBSERVING AN INCREASE IN THE SNOWFALL. THIS IS LIKELY DUE TO LAKE MICHIGAN INTERACTION AND AIDED BY 100KT 300MB EXIT REGION TO ENHANCE LIFT. LATEST RUC HAS AN EXCELLENT HANDLE ON THESE FEATURES SO WE WILL CONTINUE WITH THE CURRENT FORECAST...JUST REFRESH THE ZFP TO REMOVE MORNING TIME REFERENCES. PLENTY OF IN-HOUSE DISCUSSIONS ABOUT THE NEXT SYSTEM FOR EARLY NEXT WEEK. TRENDS CONTINUE WITH A FURTHER WEST TRACK AS SHORT WAVE DIVES SOUTH ACROSS THE DAKOTAS AND TRYING TO PHASE WITH RESIDUAL ENERGY FROM PACIFIC SYSTEM INTO THE CENTRAL PLAINS. WE WILL AWAIT FOR THE ENSEMBLES AND LOCALLY PRODUCED WRFXX BEFORE MAKING CHANGES TO OUR CURRENT HWO. BGM && .SHORT TERM...TODAY AND TONIGHT (ISSUED AT 300 AM EST) PRETTY NICE AREA OF SNOWFALL HAS DEVELOPED WITH DISTURBANCE DROPPING SOUTHEAST THROUGH THE LAKES REGION...WITH UPSTREAM VISIBILITIES IN THE 1 TO 2 MILE RANGE PREVALENT FROM WISCONSIN...NOW INTO PORTIONS OF LOWER MICHIGAN. MODELS IN GOOD AGREEMENT IN THIS VORTICITY CENTER ACROSS THE AREA...WITH ASSOCIATED QPF VALUES IN THE 0.10-0.15 RANGE. GIVEN H85 TEMPERATURES AVERAGING -10C OR SO...AND SURFACE TEMPERATURES STARTING OUT IN THE TEENS TO AROUND 20...LIQUID/SNOW RATIOS SHOULD ALLOW LOCAL AMOUNTS OF 2 INCHES OR JUST A BIT BETTER. THIS AREA OF SNOW WILL OVERSPREAD THE REGION QUICKLY THIS MORNING...AND WILL ONLY DELAY THE ARRIVAL OF CATEGORICAL SNOWFALL (80%) IN THE FAR SOUTH. THIS SNOW WILL PERSIST MUCH OF THE DAY...STARTING WITH ISENTROPIC LIFT SNOWS THIS MORNING...FOLLOWED BY AFTERNOON SNOW ASSOCIATED WITH THE VORTICITY CENTER ITSELF. THIS TO WORK OUT OF THE REGION THIS EVENING...WITH COLD OVERNIGHT LOW TEMPERATURES TONIGHT. CURRENT FORECAST IS AT TO JUST BELOW GUIDANCE VALUES AND THIS SEEMS PRETTY REASONABLE. MAY EDGE THEM DOWN JUST A DEGREE OR TWO MORE IN ANTICIPATION OF ANOTHER INCH OR TWO OF FRESH POWDER...AND AT LEAST SOME DEGREE OF CLEARING IN BEHIND THIS SYSTEM. OVERALL...THOUGH...TONIGHT/S FORECAST IS IN GOOD SHAPE. && .LONG TERM... BELOW NORMAL TEMPERATURES TO CONTINUE FOR THE FORESEEABLE FUTURE. A GOOD SHOT OF COLD AIR TO ARRIVE BY SATURDAY AS STRONG CANADIAN HIGH SETTLES OVER THE CENTRAL GREAT LAKES. WITH THE HIGH CENTERED OVER LOWER MICHIGAN ON SATURDAY...IT WILL BE INTERESTING TO SEE HOW WARM IT GETS WITH THE LATE FEBRUARY SUNSHINE. THE AIRMASS IS LOOKING VERY COLD...AS 850 MB TEMPS ARE PROGGED TO RANGE FROM -12 C SOUTH TO -16 C NORTH. WITH A GOOD DEAL OF SUNSHINE...GOING FOR MAXES IN THE 25 TO 30 DEGREE RANGE. IF CONSIDERABLE DIURNAL CLOUDS DEVELOP BY LATE MORNING...WILL BE LOOKING AT MAXES MORE IN THE 20 TO 25 DEGREE RANGE. SURFACE HIGH REMAINS OVER SOUTHEAST MICHIGAN INTO THE EVENING HOURS...WHICH SHOULD ASSURE A QUICK DROP IN TEMPERATURES. WARM ADVECTION MID/HIGH CLOUDS EXPECTED TO FILTER INTO THE REGION AFTER MIDNIGHT. EVEN SO...EXPECTING MINS TO DROP INTO THE SINGLE NUMBERS OUTSIDE OF THE CITY...PER ETA MOS. THE USUAL SUSPECTS/GOOD RADIATORS (PHN/BAX) HAVE A SHOT AT DROPPING BELOW ZERO. LATEST WATER VAPOR IMAGERY INDICATING AN IMPRESSIVE UPPER LEVEL RIDGE CENTERED OVER THE NORTHERN ROCKIES. THIS RIDGE WILL MORE OR LESS HOLD FIRM THROUGH EARLY NEXT WEEK. POTENT SHORTWAVE JUST OFF THE WESTERN CANADIAN COAST TO RIDE OVER THE TOP OF THE RIDGE TODAY...AND THEN AMPLIFY THROUGH THE WEEKEND (WITH THE HELP OF A FEW NORTHERN STREAM SHORTWAVES DIVING SOUTH)...WITH AN EVENTUAL CUTOFF UPPER LEVEL LOW DEVELOPING OVER THE GREAT LAKES REGION EARLY NEXT WEEK...PER 00Z CANADIAN/GFS. MODEL DIFFERENCES ON JUST HOW FAST THIS EVOLVES...AND WHEN PHASING OCCURS WITH THE ACTIVE SOUTHERN STREAM. REGARDLESS...THERE APPEARS TO BE A HIGH PROBABILITY A STRONG LOW PRESSURE SYSTEM WILL SPIN UP ALONG THE EAST COAST. THE QUESTION IS...WILL THERE BE ANY MOISTURE TRANSPORT INTO THE CENTRAL GREAT LAKES AS THE COASTAL BOMB TAKES OVER. A LOOK AT THE 00Z EUROPEAN REVEALS A INTENSE LOW PRESSURE SYSTEM NEAR THE SOUTHERN NEW ENGLAND BENCHMARK (40N/70W) ON MONDAY...MORE IN LINE WITH 00Z NOGAPS AND CANADIAN MODELS. MEANWHILE...00Z GFS IS MUCH FATHER WEST WITH THE SURFACE LOW...TRACKING THROUGH EASTERN NEW YORK. WHEN...WHERE...AND HOW FAST THIS COASTAL DEVELOPMENT OCCURS WILL HAVE AN IMPACT ON HOW MUCH SNOW WE SEE...ASSUMING THE 500 MB LOW IS OVER OR JUST WEST OF THE REGION. OTHERWISE...YOU CAN PRETTY MUCH FORGOT ABOUT SEEING ANY SIGNIFICANT SNOW. FOR CONTINUITY...AND THE FACT I AM NOT READY TO PUT MUCH STOCK IN ANY PARTICULAR MODEL YET...WILL CONTINUE TO MENTION THE POSSIBILITY FOR A COUPLE OF INCHES OF SNOW ON MONDAY. WILL REMOVE THE MENTION OF RAIN...AS IT APPEARS THE WARM AIR WILL PINCH OFF AS THE NORTHERN STREAM WAVE DEEPENS AND HEIGHTS FALL OVER THE GREAT LAKES. COLD TEMPERATURES TO CONTINUE THROUGH THE REST OF THE FORECAST PERIOD AS THE COLD UPPER LOW OVER THE GREAT LAKES REGION/EASTERN CANADA IS SLOW TO PUSH OFF TO THE EAST (IF AT ALL). && .AVIATION... SCATTERED TO BROKEN VFR STRATOCU WORKING BACK INTO THE REGION AHEAD OF NEXT SYSTEM AS SURFACE RIDGE AXIS CONTINUES TO SLIP OFF TO THE EAST. DO NOT ANTICIPATE ANY LOWERING OF THIS CLOUD FIELD UNTIL STRONGER OVER RUNNING DEVELOPS IN ADVANCE OF WAVE OVER THE UPPER MISSISSIPPI VALLEY. BASED ON CURRENT SATELLITE AND RADAR TRENDS LOOKS LIKE CLOUD DECK SHOULD LOWER TO MVFR AROUND 09Z NORTH TO AROUND 11-12 IN THE DTW AREA. GOOD SHOT OF OVER RUNNING TO MOVE INTO THE ENTIRE CWA BY 12Z...WITH ADDITIONAL SYNOPTIC LIFT WITH FIRST IN A SERIES OF UPPER WAVES MOVING INTO THE REGION AS WELL. SO EVEN WITH A FAIRLY DRY SOUNDING AT 00Z...EXPECT FAIRLY QUICK SATURATION AND MVFR VSBYS IN SNOW SPREADING ACROSS THE SAGINAW VALLEY AFTER 09Z AND INTO THE DTW AREA AROUND 12Z. BEST SNOWFALL/SYNOPTIC LIFT APPEARS TO BE BEFORE 18Z...LINGERING TO AROUND 21Z IN THE DTW AREA...THEN MID LEVELS BEGIN TO DRY OUT. WEAK CYCLONIC FLOW IN WAKE OF ASSOCIATED COLD FRONT AND LIMITED MOISTURE AFTER 21-00Z...SO MAINLY JUST FLURRIES FOR THE EVENING HOURS WITH MVFR CIGS CONTINUING. && .DTX WATCHES/WARNINGS/ADVISORIES... .MI...NONE. .LAKE HURON...NONE. .LAKE ST CLAIR...NONE. .MI WATERS OF LAKE ERIE...NONE. && $$ DG/SF mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 830 PM CST FRI FEB 25 2005 .UPDATE...SHORT WAVE LOBE ALONG LOWER RIOGRANDE PLAINS TO COASTAL BEND GRADUALLY SHIFTING NORTHWARD TONIGHT AS OVERRUNNING MOISTURE BEGINNING TO ENHANCE FROM RADAR IMAGERY. LATEST RUC (RAPID UPDATE CYCLE) MODEL SHOWS LOBE MOVING NORTHEAST OVER AREA WITH INCREASING INTENSITY LATE TONIGHT. WEAK OVERRUNNING MOISTURE WILL ACCOMPANY THE DISTURBANCE WITH CHANCES OF RAIN INCREASING FROM WEST TO EAST AFTER MIDNIGHT. THIS IS REFLECTED WELL IN THE CURRENT FORECAST SO NO UPDATE IS PLANNED. && .PREV DISCUSSION... /ISSUED 315 PM CST FRI FEB 25 2005/ DISCUSSION... CONTINUED CLOUDY...DAMP AND COLD CONDITIONS EXPECTED THRU SATURDAY. FORECASTS SHOW AREA OF COOL AIR CONTINUING OVER S CNTRL TX THRU SATURDAY...AS WX SYSTEM ALOFT TO THE WEST MOVES JUST NORTH OF AREA. WX PATTERN IS SIMILAR TO FEB 1ST...EXCEPT TEMPS ARE A LITTLE WARMER WITH THE PATTERN THIS TIME. FORECASTS CONT TO SHOW GOOD WARM AIR ADV ABOVE SHALLOW COOL AIR SATURDAY. THIS WILL MAKE FOR GOOD CHANCE OF RAIN. HIGH TEMPS APPEAR LIMITED SATURDAY IN RAINY PATTERN...SO WILL SHOW LITTLE WARMING FROM OVERNIGHT LOWS. LINGERING RAIN SATURDAY EVENING MAINLY OVER EAST HALF OF AREA IS EXPECTED TO DECREASE FROM THE WEST AFTER MIDNIGHT TO EARLY SUNDAY MORNING. EXPECT PARTLY CLOUDY SKIES TO EVOLVE SUNDAY FROM THE WEST...WITH WARMER TEMPS. DRIER WEATHER CONTINUING ON MONDAY. RETURN SOUTHERLY WINDS TUESDAY EXPECTED TO BRING INCREASING CLOUDS TUESDAY NIGHT AND EARLY WEDNESDAY...WITH POSSIBLE RAIN OR SHOWERS WEDNESDAY. CLEARING SKIES EXPECTED THURSDAY. PARTLY CLOUDY SKIES ARE EXPECTED TO CONTINUE FRIDAY THRU THE FIRST WEEKEND OF MARCH. && .EWX WATCHES/WARNINGS/ADVISORIES...TX...NONE. && $$ 19/02 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 326 AM MST SAT FEB 26 2005 .SHORT TERM... (TODAY AND TONIGHT) .SHORT TERM... (TODAY AND TONIGHT) CURRENTLY A FEW SHOWERS ALONG THE SANGRES...EVEN AN EARLIER SPOTTER REPORT NEAR CRESTONE OF 1/2 INCH FROM A SNOW SHOWER THERE. UPPER LOW PER WV IMAGERY AND RUC ANALYSIS PARKED OVER COLORADO. AS DAYTIME HEATING SETS IN...LAPSE RATES JUMP TO 7.5-8.5C ACROSS THE STATE. MOISTURE IS NOT ABUNDANT WITH ONLY ABOUT A QUARTER INCH IN THE COLUMN...AND MOST MOISTURE WILL BE OVER THE MTN AREAS WITH A WEAK LEE TROF ACROSS THE PLAINS. EXPECT SCATTERED SHOWERS IN MTNS... AND MAINLY VIRGA ACROSS PLAINS. HOWEVER WITH 8.5C LAPSE RATES CAN'T RULE OUT AN OCCASIONAL STRIKE OUT EAST. WILL KEEP ISOLD AFTERNOON THUNDER AREA WIDE. TWO PROBLEMS WITH A CONVECTIVE DAY LIKE TODAY... ITS DIFFICULT TO PINPOINT EXACTALLY WHERE CONVECTIVE SNOW SHOWERS MAY FORM AND DROP A FEW INCHES OF SNOW. HAVE PAINTED A BROAD 1-2 ACROSS MOST WEST/CNTRL MTNS AND HIGH VALLEYS...HOWEVER WOULDN'T BE SURPRISED AT ALL TO GET REPORTS OF LOCALLY HIGHER AMOUNTS. ALSO...WITH VIRGA ON THE PLAINS...ALSO EXPECT SOME LOCALLY GUSTY WINDS. WINDS ALOFT ARE NOT ALL THAT STRONG TODAY...BUT MIGHT GET SOME LOCAL 30-40 KTS UNDER A DISSIPATING VIRGA SHOWER. TEMPS EXPECTED TO BE VERY SIMILAR TO YESTERDAYS NUMBERS WITH LOCAL VARIATIONS FROM CLOUDS AND PRECIP. TONIGHT...UPPER LOW PUSHES ACROSS THE STATE TONIGHT...AND NEXT COLDFRONT ROLLS INTO THE PLAINS BY EARLY MORNING. AS A RESULT...HAVE KEPT SCT MTN AND ISOLD PLAINS POPS...BUT DROPPED THE THUNDER. KC .LONG TERM... (SUNDAY THROUGH FRIDAY ...COLD AND BLUSTERY SUNDAY THEN WARMER INTO NEXT WEEK... BY SUNDAY MORNING...A COLD FRONT WILL BE MOVING ACROSS THE CWA ASSOCIATED WITH A FAIRLY SHARP SHORT WAVE (REMNANT LOW FROM THE LAST WEEK GONE BY) AT MID LVLS. GUSTY NORTH WINDS OF 10 TO 20 MPH WITH GUST TO 30 WILL OCCUR ACROSS THE PLAINS. SCATTERED SHOWERS WILL BE ACROSS THE REGION BUT QPF VALUES WILL BE QUITE LOW. I BELIEVE BEST SHOT OF PRECIP WILL ONCE AGAIN BE DOWN ALONG THE RATON MESA/S SANGRES AS FLOW MAY BRIEFLY GO NNE ENHANCING THE OROGRAPHICS IN THIS REGION. AFTER THIS SYSTEM GOES BY...A RIDGE BUILDS OVER THE WEST COAST. THIS WILL KEEP CO IN NW FLOW. A COUPLE OF WEAK SHORT WAVES ARE FCST TO COME THROUGH...ESPECIALLY AROUND TUE. THIS WILL BRING ANOTHER SHOT OF SOME LIGHT SNOW OVER THE MTNS...ESPECIALLY C MTNS. WITH A GENERAL WESTERLY COMPONENT TO THE FLOW AND THE COOLEST AIR OFF TO OUR NE...THE PLAINS SHOULD BE RATHER TRANQUIL WITH HIGHS GENERALLY IN THE 50S/L60S THROUGH NEXT WEEK. \/HODANISH. && .PUB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 AM EST SAT FEB 26 2005 .DISCUSSION... MAIN FCST ISSUE IS SYNOPTIC SNOW LATE TONIGHT THRU SUN EVENING AND THEN TRANSITION TO SIGNIFICANT N/NE WIND LAKE EFFECT/LAKE ENHANCED SNOW MON-TUE. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE EXTENDING N FROM THE NRN U.S. ROCKIES AND SRN STREAM UNDERCUTTING RIDGE ACROSS SRN ROCKIES. DEEP TROF EXTENDS FROM NRN CANADA INTO THE ERN LAKES/NEW ENGLAND UPSTREAM OF MASSIVE BLOCKING HIGH CENTERED OVER GREENLAND/ICELAND. RESULT IS NW FLOW OVER FCST AREA THIS MORNING. NEXT SHORTWAVE OF INTEREST IS CURRENTLY OVER NRN ALBERTA AND IS EXPECTED TO DIG SHARPLY INTO THE GREAT LAKES SUN. AT THE SFC...HIGH PRES WAS CENTERED OVER NRN ONTARIO WITH RIDGE EXTENDING S ACROSS WRN LAKE SUPERIOR. LIGHT LES CONTINUES IN NRLY LOW-LEVEL FLOW ACROSS CNTRL AND ERN LAKE SUPERIOR. EXPECT A FAIRLY TRANQUIL BUT CHILLY DAY TODAY AS SFC RIDGE DRIFTS E ACROSS UPPER MI/LAKE SUPERIOR. WITH 850MB TEMPS REMAINING BLO -16C ACROSS THE E 2/3RDS OF LAKE SUPERIOR THRU THE DAY...LIGHT LES WILL CONTINUE AND WILL ONLY END WHEN WINDS SWITCH TO AN OFFSHORE DIRECTION. 950MB WINDS FROM GFS/NAM/WSETA INDICATE AN ONSHORE COMPONENT WILL CONTINUE THRU THE AFTN FROM ALGER COUNTY W TO THE KEWEENAW. WILL THUS NEED TO MAINTAIN SCT -SHSN/FLURRIES TODAY IN THOSE AREAS. ELSEWHERE...EXPECT A MIX OF SUN/CLOUDS. WILL LEAN TOWARD LOW END OF MOS GUIDANCE GIVEN CHILLY START TO THE DAY AND THERMAL TROF ONLY SLOWLY EDGING E. MODELS ARE COMING INTO BETTER AGREEMENT ON EVOLUTION OF TROF AMPLIFICATION OVER THE GREAT LAKES SUN-TUE. IN GENERAL...PREFER THE SLIGHTLY SLOWER PROGRESSION INDICATED BY THE ECMWF/CANADIAN WHICH HAVE SHOWN VERY GOOD RUN-TO-RUN CONTINUITY WITH UPPER LOW CLOSING OFF SOMEWHERE OVER WI/LWR MI LATE MON/EARLY TUE. UKMET HAS COME AROUND TO A SLIGHTLY SOLUTION THIS RUN AS WELL. THIS WILL HAVE IMPLICATIONS ON DURATION OF LAKE ENHANCED SNOW THAT WILL DEVELOP AS WINDS BACK TO A NE TO N DIRECTION LATE SUN THRU TUE. IN THE MEANTIME...NRN STREAM BEGINS TO AMPLIFY TONIGHT WITH SHORTWAVE CURRENTLY OVER ALBERTA DROPPING INTO THE DAKOTAS BY 12Z. GFS STILL REMAINS QUICKEST WITH PCPN AS IT SPREADS SNOW ACROSS ENTIRE FCST AREA BY 12Z. PREFER THE SLOWER SNOW ONSET INDICATED BY NAM/CANADIAN AS DRY AIRMASS FEEDING OUT OF DEPARTING RIDGE ON SE WINDS SHOULD SLOW MOISTENING OF THE COLUMN. WILL CONTINUE ALONG LINES OF CURRENT FCST AND BRING SNOW TO ABOUT A KMQT/KMNM LINE TONIGHT. WILL UP POPS TO LIKELY LATE OVER THE FAR W GIVEN STRONG MODEL AGREEMENT ON SNOW THERE. MAYBE AN INCH FAR WEST BY 12Z. SNOWY DAY ON TAP ACROSS ENTIRE FCST AREA SUN/SUN EVENING. SHARPENING UPPER TROF/850MB LOW DEVELOPING SE INTO NRN WI AND TIGHTENING BAROCLINIC ZONE WILL SET THE STAGE FOR POSSIBLE SIGNIFICANT SNOW ACCUMULATIONS. NAM/GFS SHOW DECENT ISENTROPIC ASCENT ON 285-290K SFCS WITH 2-3G/KG AVBL WHICH WOULD TRANSLATE TO 4-6 INCH 12HR SNOWFALL. MODELS ALSO SHOW IMPRESSIVE 700MB UPWARD MOTION. HOWEVER...INTERESTING ASPECT WILL BE THE ADVECTION OF VERY STEEP MIDLEVEL (700-500MB) LAPSE RATES OF 7-7.5C/KM INTO UPPER MI WHICH IS SHOWN MOST DRAMATICALLY ON NGM/NAM. STEEP LAPSE RATES COMBINED WITH FAIRLY IMPRESSIVE LOW-MID LEVEL FRONTOGENESIS WILL PROBABLY LEAD TO SOME CONVECTIVE ELEMENTS AND PERIODIC HIGH SNOWFALL RATES SUN. 12HR MODEL QPF IS GENERALLY IN THE QUARTER TO HALF INCH RANGE...BUT GIVEN FORCING AND POTENTIAL CONVECTION...HAVE A FEELING THAT IS UNDERDONE. IN GENERAL...EXPECT SNOW TOTALS BY LATE SUN EVENING TO RANGE FROM 4 TO 8 INCHES WITH THE LIGHTER AMOUNTS W AND THE HIGHER AMOUNTS OVER THE SE AND ERN FCST AREA WHERE BETTER FORCING OCCURS. THERE COULD BE SOME ENHANCEMENT OFF LAKE MICHIGAN IN SE FLOW...BUT IT LOOKS LIKE FETCH IN WHICH THERE IS FAVORABLE INSTABILITY IS TOO SHORT TO PROVIDE MUCH ENHANCEMENT. THERE MAY BE SOME ENHANCEMENT ON THE KEWEENAW AS WELL...BUT 950MB FLOW LOOKS A BIT TOO MUCH S OF E TO BE A FACTOR UNTIL LATE AFTN WHEN FORCING IS EXITING. STILL IT WILL BE SOMETHING TO LOOK AT AGAIN IN LATER MODEL RUNS. SO...GOING WATCH FOR IRON TO DELTA COUNTIES IS ON TRACK (WARNING CRITERIA IS 6 INCHES IN 12HRS THERE). SRN SCHOOLCRAFT ALSO HAS THE LOWER CRITERIA AND WILL ADD THAT AREA TO WATCH AS WELL. MARQUETTE/ALGER/LUCE MAY GET CLOSE TO WARNING CRITERIA OF 8 INCHES IN 12HRS...BUT DON'T FEEL WATCH IS NECESSARY SINCE MORE LIKELY AMOUNTS ARE 5-7 INCHES. AS MAIN SYNOPTIC SNOW EXITS SUN NIGHT...FCST GETS MORE COMPLICATED AS THERE WILL BE A TRANSITION TO LAKE ENHANCED SNOW OFF LAKE SUPERIOR IN NE FLOW. GFS/NAM SUGGEST IT WON'T BE UNTIL AFTER MIDNIGHT SUN NIGHT THAT LOW-LEVEL WINDS BECOME NE...BUT WITH A PREFERENCE FOR THE SLOWER ECMWF/CANADIAN/UKMET SOLUTIONS...DON'T EXPECT A NE WIND TO DEVELOP UNTIL SOMETIME MON MORNING. AT THIS POINT...WILL MAINTAIN GOING FCST OF LIKELY POPS IN THE WAKE OF THE MAIN SYNOPTIC SNOW SUN NIGHT WITH SOME LIGHT ACCUMULATIONS OF AN INCH OR TWO. WILL NEED TO WATCH THE KEWEENAW WITH POTENTIAL OF ENHANCEMENT IN ERLY FLOW. EXPECT MAIN LAKE ENHANCED PERIOD TO BE MON INTO EARLY TUE WITH DEEP CYCLONIC NNE FLOW/DEEP MOISTURE AND 850MB TEMPS FALLING TO -15 TO -17C. WITH PREFERENCE FOR THE SLOWER SOLUTION AS MENTIONED PREVIOUSLY...DEEP MOISTURE SHOULD HANG BACK LONGER THAN GFS/NAM INDICATE...AND IN GENERAL ENHANCEMENT WILL BE MORE PRONOUNCED WITH MID/UPPER LOW HANGING BACK CLOSER TO UPPER MI THRU TUE MORNING (CANADIAN/ECMWF HAVE 5H LOW OVER NE LWR MI AT 12Z TUE). FEEL VERY CONFIDENT THAT WARNING AMOUNTS WILL BE EASILY EXCEEDED ACROSS BARAGA/MARQUETTE/ALGER COUNTIES...AND THIS WILL LIKELY BE THE BIGGEST SNOW OF THE SEASON IN THAT AREA. OUT W...GOGEBIC/ONTONAGON WILL BE FAVORED...BUT THAT AREA WILL SLIP OUT OF DEEPER MOISTURE SOONER. EVEN SO...THAT AREA SHOULDN'T HAVE TROUBLE EXCEEDING WARNING CRITERIA. FETCH WILL BE TOO LIMITED TO BRING SIGNIFICANT SNOW INTO LUCE COUNTY. THE KEWEENAW IS ALWAYS TRICKY UNDER NNE FLOW WHICH IS MORE PARALLEL TO THE TERRAIN. WARNING AMOUNTS POSSIBLE THERE...ESPECIALLY KEWEENAW COUNTY...BUT CONFIDENCE IS LOWER THAN AREAS TO THE W AND E OF THERE. WILL NOT ISSUE WATCHES WITH THIS FCST ISSUANCE SINCE PERIOD OF INTEREST IS OUT IN THE MON-TUE TIMEFRAME...BUT WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER OUTLOOK. && .MQT...WATCHES/WARNINGS/ADVISORIES... HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. WINTER STORM WATCH SUNDAY MIZ010-011. WINTER STORM WATCH SUNDAY INTO SUNDAY EVENING MIZ012>014. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 950 AM CST SAT FEB 26 2005 .DISCUSSION... LARGE AREA OF RAIN MOVING INTO EAST TX. CURRENT TRENDS AND RUC MOISTURE FIELDS SUGGEST LIGHT RAIN BEGINNING TO FALL EAST TX BY LATE AFTERNOON APPEAR ON TRACK. TEMPS HAVE SOME 10 DEGREE TO GO TO REACH UPPER 50S THIS AFTERNOON...MAY BE HARD PRESSED UNDER THICKENING HIGH CLOUDS...BUT SOME WARMING WILL OCCUR...SO SHOULD BE CLOSE. NO UPDATE NEEDED. PRELIMS ARE NEXT... VII && .PRELIMINARY POINT TEMPS/POPS... SHV 57 44 49 42 / 0 80 80 20 MLU 59 44 48 41 / 0 60 80 20 DEQ 58 43 48 40 / 0 60 70 20 TXK 58 44 48 41 / 0 70 80 20 ELD 59 43 47 41 / 0 60 80 20 TYR 57 44 53 41 / 30 80 50 20 GGG 57 44 51 42 / 30 80 50 20 LFK 57 45 56 43 / 30 80 50 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ la AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CARIBOU ME 1021 AM EST SAT FEB 26 2005 .SYNOPSIS...INTENSIFYING LOW PRESSURE EAST OF NOVA SCOTIA WILL REACH NEWFOUNDLAND TODAY. A WEAK AREA OF LOW PRESSURE OVER NEW YORK STATE WILL TRACK OFF THE SOUTHERN NEW ENGLAND COAST THIS AFTERNOON. HIGH PRESSURE BUILDING IN FROM THE MIDWEST AND STRONG LOW PRESSURE OVER EASTERN CANADA WILL PROVIDE COLD AND WINDY CONDITIONS ACROSS THE REGION ON SUNDAY. HIGH PRESSURE CENTERED OVER THE REGION SUNDAY NIGHT WILL MOVE EAST EARLY MONDAY. LOW PRESSURE WILL APPROACH FROM THE SOUTH MONDAY NIGHT AND TUESDAY. && .SHORT TERM (REST OF TODAY)...CURRENT SAT INDICATES CLEAR SKIES ACROSS ENTIRE STATE OF MAINE AND WITH RUC INDICATING DRY NW FLOW TO CONTINUE FOR THE REST OF THE DAY. HAVE UPDATED ZONES FOR THIS AFTERNOON TO DECREASE CLOUDS ACROSS ENTIRE CWA AND REMOVE POPS FOR NORTHERN SECTIONS. BUFKIT INDICATES POSSIBLE CU TO DEVELOP OVER NORTHERN SECTIONS THIS AFTERNOON SO WILL GO WITH PARTLY CLOUDY SKIES ACROSS NORTHERN AND CENTRAL SECTIONS. && .PREVIOUS DISCUSSION... (ISSUED 335 AM EST SAT FEB 26 2005) SYNOPSIS...INTENSIFYING LOW PRESSURE EAST OF NOVA SCOTIA WILL REACH NEWFOUNDLAND TODAY. A WEAK AREA OF LOW PRESSURE OVER NEW YORK STATE WILL TRACK OFF THE SOUTHERN NEW ENGLAND COAST THIS AFTERNOON. HIGH PRESSURE BUILDING IN FROM THE MIDWEST AND STRONG LOW PRESSURE OVER EASTERN CANADA WILL PROVIDE COLD AND WINDY CONDITIONS ACROSS THE REGION ON SUNDAY. HIGH PRESSURE CENTERED OVER THE REGION SUNDAY NIGHT WILL MOVE EAST EARLY MONDAY. LOW PRESSURE WILL APPROACH FROM THE SOUTH MONDAY NIGHT AND TUESDAY. SHORT TERM (TODAY THROUGH SUNDAY NIGHT)... PRETTY QUIET OVERALL IN THE SHORT TERM. UPPER TROUGH WILL REMAIN ACROSS THE NE THROUGH THE WEEKEND. INTENSIFYING LOW PRESSURE EAST OF NOVA SCOTIA WILL MOVE NE OF THE AREA TODAY...THEN BEGIN RETROGRADING BACK TOWARDS NORTHERN QUEBEC SUNDAY. EXPECT SKIES TO BE PARTLY CLOUDY TODAY ACROSS THE CWA...BECOMING MOSTLY CLOUDY IN THE AFTERNOON ACROSS THE NORTHERN HALF OF THE CWA. PUT IN CHANCE POPS FOR -SHSN THIS AFTERNOON AND EVENING ACROSS THE MOUNTAINS WITH APPROACHING VORT MAX AND COLD AIR ADVECTION IN THE LOWER LEVELS. NORTHWEST FLOW QUICKLY STRENGTHENS SATURDAY EVENING AS HIGH PRESSURE AXIS APPROACHES FROM THE WEST. WITH MORNINGS LOWS NEAR ZERO ACROSS THE NORTH...WILL HAVE TO KEEP AN EYE ON THE POSSIBILITY OF A WIND CHILL ADVISORY FOR SUNDAY MORNING. LONG TERM (MONDAY THROUGH FRIDAY)... DECIDED ON A BLEND OF THE GEM & UKMET W/THE ECMWF SOMEWHAT CLOSE TO THESE 2 MODELS IN REGARDS TO STORM SYSTEM PROGGED TO MOVE ALONG THE EASTERN SEABOARD INTO NORTHERN NEW ENGLAND EARLY NEXT WEEK. NCEP MDL DIAGNOSTIC DISC SUPPORTS THIS AS WELL. GFS COULD BE SUFFERING FROM CONVECTIVE FEEDBACK. RAISED THE BAR ON POPS FOR TUE & WENT W/CATEGORICAL POPS. LEANED A BIT COOLER ON TEMPS. GFS NOW COMING IN COOLER. WINDS WERE ADJUSTED FOR TUE INTO WED USING THE DGEX W/MATCH GUIDANCE OVERLAYED. THEREFORE...WINDS BOOSTED W/ENE GRADIENT TIGHTENING AS STORM INTENSIFIES. THIS MATCHES PRETTY WELL W/GYX. THANX GYX FOR INPUT. WILL UPDATE THE SPS THAT WAS ISSUED EARLIER FOR POTENTIAL FOR SIGNIFICANT WX EVENT. NO CHGS WERE MADE BEYOND WED TIME FRAME FOR CONTINUITY PURPOSES. AVIATION... LOOKING FOR VFR OVER THE NEXT 24 HRS. PILOTS CAN EXPECT A CHOP THIS AFTERNOON INTO THE EVENING W/INCG NW FLOW. MARINE... NW FLOW TODAY WILL QUICKLY PICK UP TONIGHT AS HIGH PRESSURE APPROACHES FROM THE WEST AND LAST THROUGH SUNDAY INTO SUNDAY NIGHT. SCA WILL LIKELY BE REQUIRED TONIGHT FOR WINDS AND SEAS. DID BOOST WINDS/SEAS IN THE EXTENDED GRIDS W/INCG ENE FLOW. NOT GOING FOR STORM THIS FAR OUT. DID PUSH WINDS TO 40 KTS ON TUE & THEN WINDS DROP & VEER TO WSW AS SYSM PULLS NWD. CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY MAY BE REQUIRED FOR TONIGHT. $$ SHORT TERM/MARINE...CALDERON LONG TERM/MARINE...HEWITT && $$ SHORT TERM/MARINE...FOSTER me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1010 AM EST SAT FEB 26 2005 .DISCUSSION... MAIN ISSUE TO CONTEND WITH IN THE SHORT TERM IS THE SNOW SHOWER ACTIVITY ONGOING OVER THE NORTHERN KEWEENAW AS WELL AS NORTH CENTRAL AND NORTHEAST UPPER MICHIGAN. THE BANDING HAS BEEN FAIRLY DISORGANIZED DUE TO SOME BOUNDARY LAYER SHEAR AND PROGRESSIVELY VEERING WINDS. HOWEVER...TAMDAR SOUNDINGS FROM KCMX AND KSAW FROM AROUND 12Z SHOWED THE INVERSION NEAR 850MB...WITH DELTA-T VALUES NEAR 20 AND A FAIRLY MOIST SUB-INVERSION PROFILE. IN ADDITION...THE CAPE CONTAINED WITHIN THE SOUNDINGS IS CO-LOCATED WITH THE DEPOSITIONAL SNOW GROWTH LAYER...WHICH HAS LED TO THE PRODUCTION OF LARGE DENDRITIC CRYSTALS. LIGHT WINDS HAVE PREVENTED THE FLAKES FROM FRACTURING MUCH...WHICH HAS ALLOWED THE SNOW TO STACK UP NICELY IN SOME LOCATIONS. SINCE THE BANDS HAVE SHIFTED AROUND AND HAVE BEEN SOMEWHAT CELLULAR IN NATURE...MOST SPOTS ONLY SAW UP TO 3 INCHES OVERNIGHT INTO THIS MORNING. THE ACTIVITY HAS BEEN MOST PERSISTENT SOUTHEAST OF MARQUETTE...AND A SPOTTER NEAR CARLSHEND REPORTED 8 INCHES OF SNOW FROM LATE FRIDAY AFTERNOON THROUGH THIS MORNING. THE SURFACE RIDGE CURRENTLY LOCATED NORTH OF LAKE SUPERIOR WILL DRIFT EAST THROUGH THE DAY TODAY...AND BOUNDARY LAYER WINDS ARE EXPECTED TO VEER EAST THROUGH THE AFTERNOON. THIS SHOULD LEAD TO CONTINUED DISORGANIZATION OF THE LES...ALTHOUGH IT MAY ALSO HELP PUSH THE SNOW SHOWERS FARTHER INLAND OVER WESTERN MARQUETTE COUNTY FOR A BRIEF TIME. WINDS CONTINUE TO VEER DURING THE LATE AFTERNOON AND EVENING HOURS...WITH BOUNDARY LAYER FLOW BECOMING SOUTHEAST BY EARLY EVENING. THIS FACT...COMBINED WITH A LOWERING INVERSION AND ASSOCIATED BOUNDARY LAYER DRYING...WILL BRING AN END TO THE SNOW SHOWERS AND FLURRIES BY EARLY EVENING. ONLY MINOR ADDITIONAL ACCUMULATIONS ARE EXPECTED THIS AFTERNOON SINCE THINGS WILL BE ON THE DOWN TREND AND BANDS WILL BE SHIFTING IN ORIENTATION. HOWEVER...SOME BRIEF HEAVY BURSTS OF SNOW WILL PERSIST NEAR M-28 FROM NEGAUNEE EASTWARD INTO EARLY AFTERNOON. TRH .PREV DISCUSSION... MAIN FCST ISSUE IS SYNOPTIC SNOW LATE TONIGHT THRU SUN EVENING AND THEN TRANSITION TO SIGNIFICANT N/NE WIND LAKE EFFECT/LAKE ENHANCED SNOW MON-TUE. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE EXTENDING N FROM THE NRN U.S. ROCKIES AND SRN STREAM UNDERCUTTING RIDGE ACROSS SRN ROCKIES. DEEP TROF EXTENDS FROM NRN CANADA INTO THE ERN LAKES/NEW ENGLAND UPSTREAM OF MASSIVE BLOCKING HIGH CENTERED OVER GREENLAND/ICELAND. RESULT IS NW FLOW OVER FCST AREA THIS MORNING. NEXT SHORTWAVE OF INTEREST IS CURRENTLY OVER NRN ALBERTA AND IS EXPECTED TO DIG SHARPLY INTO THE GREAT LAKES SUN. AT THE SFC...HIGH PRES WAS CENTERED OVER NRN ONTARIO WITH RIDGE EXTENDING S ACROSS WRN LAKE SUPERIOR. LIGHT LES CONTINUES IN NRLY LOW-LEVEL FLOW ACROSS CNTRL AND ERN LAKE SUPERIOR. EXPECT A FAIRLY TRANQUIL BUT CHILLY DAY TODAY AS SFC RIDGE DRIFTS E ACROSS UPPER MI/LAKE SUPERIOR. WITH 850MB TEMPS REMAINING BLO -16C ACROSS THE E 2/3RDS OF LAKE SUPERIOR THRU THE DAY...LIGHT LES WILL CONTINUE AND WILL ONLY END WHEN WINDS SWITCH TO AN OFFSHORE DIRECTION. 950MB WINDS FROM GFS/NAM/WSETA INDICATE AN ONSHORE COMPONENT WILL CONTINUE THRU THE AFTN FROM ALGER COUNTY W TO THE KEWEENAW. WILL THUS NEED TO MAINTAIN SCT -SHSN/FLURRIES TODAY IN THOSE AREAS. ELSEWHERE...EXPECT A MIX OF SUN/CLOUDS. WILL LEAN TOWARD LOW END OF MOS GUIDANCE GIVEN CHILLY START TO THE DAY AND THERMAL TROF ONLY SLOWLY EDGING E. MODELS ARE COMING INTO BETTER AGREEMENT ON EVOLUTION OF TROF AMPLIFICATION OVER THE GREAT LAKES SUN-TUE. IN GENERAL...PREFER THE SLIGHTLY SLOWER PROGRESSION INDICATED BY THE ECMWF/CANADIAN WHICH HAVE SHOWN VERY GOOD RUN-TO-RUN CONTINUITY WITH UPPER LOW CLOSING OFF SOMEWHERE OVER WI/LWR MI LATE MON/EARLY TUE. UKMET HAS COME AROUND TO A SLIGHTLY SOLUTION THIS RUN AS WELL. THIS WILL HAVE IMPLICATIONS ON DURATION OF LAKE ENHANCED SNOW THAT WILL DEVELOP AS WINDS BACK TO A NE TO N DIRECTION LATE SUN THRU TUE. IN THE MEANTIME...NRN STREAM BEGINS TO AMPLIFY TONIGHT WITH SHORTWAVE CURRENTLY OVER ALBERTA DROPPING INTO THE DAKOTAS BY 12Z. GFS STILL REMAINS QUICKEST WITH PCPN AS IT SPREADS SNOW ACROSS ENTIRE FCST AREA BY 12Z. PREFER THE SLOWER SNOW ONSET INDICATED BY NAM/CANADIAN AS DRY AIRMASS FEEDING OUT OF DEPARTING RIDGE ON SE WINDS SHOULD SLOW MOISTENING OF THE COLUMN. WILL CONTINUE ALONG LINES OF CURRENT FCST AND BRING SNOW TO ABOUT A KMQT/KMNM LINE TONIGHT. WILL UP POPS TO LIKELY LATE OVER THE FAR W GIVEN STRONG MODEL AGREEMENT ON SNOW THERE. MAYBE AN INCH FAR WEST BY 12Z. SNOWY DAY ON TAP ACROSS ENTIRE FCST AREA SUN/SUN EVENING. SHARPENING UPPER TROF/850MB LOW DEVELOPING SE INTO NRN WI AND TIGHTENING BAROCLINIC ZONE WILL SET THE STAGE FOR POSSIBLE SIGNIFICANT SNOW ACCUMULATIONS. NAM/GFS SHOW DECENT ISENTROPIC ASCENT ON 285-290K SFCS WITH 2-3G/KG AVBL WHICH WOULD TRANSLATE TO 4-6 INCH 12HR SNOWFALL. MODELS ALSO SHOW IMPRESSIVE 700MB UPWARD MOTION. HOWEVER...INTERESTING ASPECT WILL BE THE ADVECTION OF VERY STEEP MIDLEVEL (700-500MB) LAPSE RATES OF 7-7.5C/KM INTO UPPER MI WHICH IS SHOWN MOST DRAMATICALLY ON NGM/NAM. STEEP LAPSE RATES COMBINED WITH FAIRLY IMPRESSIVE LOW-MID LEVEL FRONTOGENESIS WILL PROBABLY LEAD TO SOME CONVECTIVE ELEMENTS AND PERIODIC HIGH SNOWFALL RATES SUN. 12HR MODEL QPF IS GENERALLY IN THE QUARTER TO HALF INCH RANGE...BUT GIVEN FORCING AND POTENTIAL CONVECTION...HAVE A FEELING THAT IS UNDERDONE. IN GENERAL...EXPECT SNOW TOTALS BY LATE SUN EVENING TO RANGE FROM 4 TO 8 INCHES WITH THE LIGHTER AMOUNTS W AND THE HIGHER AMOUNTS OVER THE SE AND ERN FCST AREA WHERE BETTER FORCING OCCURS. THERE COULD BE SOME ENHANCEMENT OFF LAKE MICHIGAN IN SE FLOW...BUT IT LOOKS LIKE FETCH IN WHICH THERE IS FAVORABLE INSTABILITY IS TOO SHORT TO PROVIDE MUCH ENHANCEMENT. THERE MAY BE SOME ENHANCEMENT ON THE KEWEENAW AS WELL...BUT 950MB FLOW LOOKS A BIT TOO MUCH S OF E TO BE A FACTOR UNTIL LATE AFTN WHEN FORCING IS EXITING. STILL IT WILL BE SOMETHING TO LOOK AT AGAIN IN LATER MODEL RUNS. SO...GOING WATCH FOR IRON TO DELTA COUNTIES IS ON TRACK (WARNING CRITERIA IS 6 INCHES IN 12HRS THERE). SRN SCHOOLCRAFT ALSO HAS THE LOWER CRITERIA AND WILL ADD THAT AREA TO WATCH AS WELL. MARQUETTE/ALGER/LUCE MAY GET CLOSE TO WARNING CRITERIA OF 8 INCHES IN 12HRS...BUT DON'T FEEL WATCH IS NECESSARY SINCE MORE LIKELY AMOUNTS ARE 5-7 INCHES. AS MAIN SYNOPTIC SNOW EXITS SUN NIGHT...FCST GETS MORE COMPLICATED AS THERE WILL BE A TRANSITION TO LAKE ENHANCED SNOW OFF LAKE SUPERIOR IN NE FLOW. GFS/NAM SUGGEST IT WON'T BE UNTIL AFTER MIDNIGHT SUN NIGHT THAT LOW-LEVEL WINDS BECOME NE...BUT WITH A PREFERENCE FOR THE SLOWER ECMWF/CANADIAN/UKMET SOLUTIONS...DON'T EXPECT A NE WIND TO DEVELOP UNTIL SOMETIME MON MORNING. AT THIS POINT...WILL MAINTAIN GOING FCST OF LIKELY POPS IN THE WAKE OF THE MAIN SYNOPTIC SNOW SUN NIGHT WITH SOME LIGHT ACCUMULATIONS OF AN INCH OR TWO. WILL NEED TO WATCH THE KEWEENAW WITH POTENTIAL OF ENHANCEMENT IN ERLY FLOW. EXPECT MAIN LAKE ENHANCED PERIOD TO BE MON INTO EARLY TUE WITH DEEP CYCLONIC NNE FLOW/DEEP MOISTURE AND 850MB TEMPS FALLING TO -15 TO -17C. WITH PREFERENCE FOR THE SLOWER SOLUTION AS MENTIONED PREVIOUSLY...DEEP MOISTURE SHOULD HANG BACK LONGER THAN GFS/NAM INDICATE...AND IN GENERAL ENHANCEMENT WILL BE MORE PRONOUNCED WITH MID/UPPER LOW HANGING BACK CLOSER TO UPPER MI THRU TUE MORNING (CANADIAN/ECMWF HAVE 5H LOW OVER NE LWR MI AT 12Z TUE). FEEL VERY CONFIDENT THAT WARNING AMOUNTS WILL BE EASILY EXCEEDED ACROSS BARAGA/MARQUETTE/ALGER COUNTIES...AND THIS WILL LIKELY BE THE BIGGEST SNOW OF THE SEASON IN THAT AREA. OUT W...GOGEBIC/ONTONAGON WILL BE FAVORED...BUT THAT AREA WILL SLIP OUT OF DEEPER MOISTURE SOONER. EVEN SO...THAT AREA SHOULDN'T HAVE TROUBLE EXCEEDING WARNING CRITERIA. FETCH WILL BE TOO LIMITED TO BRING SIGNIFICANT SNOW INTO LUCE COUNTY. THE KEWEENAW IS ALWAYS TRICKY UNDER NNE FLOW WHICH IS MORE PARALLEL TO THE TERRAIN. WARNING AMOUNTS POSSIBLE THERE...ESPECIALLY KEWEENAW COUNTY...BUT CONFIDENCE IS LOWER THAN AREAS TO THE W AND E OF THERE. WILL NOT ISSUE WATCHES WITH THIS FCST ISSUANCE SINCE PERIOD OF INTEREST IS OUT IN THE MON-TUE TIMEFRAME...BUT WILL CONTINUE TO HIGHLIGHT IN THE HAZARDOUS WEATHER OUTLOOK. ROLFSON && .MQT...WATCHES/WARNINGS/ADVISORIES... HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. WINTER STORM WATCH SUNDAY MIZ010-011. WINTER STORM WATCH SUNDAY INTO SUNDAY EVENING MIZ012>014. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 930 AM CST SAT FEB 26 2005 FORECAST CHALLENGE CONCERNS TEMPERATURES AND PCPN INITIATION. LOW PRESSURE ORGANIZING OVER NORTHERN HIGH PLAINS IN RESPONSE TO APPROACHING SHORTWAVE ENERGY ALONG AB/SASK/MT BORDER REGION. COLUMN INITIALLY DRY FROM 12Z UA ANALYSIS WITH ANY MOIST ADVECTION DURING DAY CONFINED TO WELL BLO 850MB. 20F DEWPOINTS OVER SE 1/4 OF SD HOWEVER WITH SE LOW LEVEL FLOW PREFER RUC SOLUTION IN NOT BRINGING THESE HIGHER DEWPOINTS ACROSS BORDER UNTIL MID/LATE AFTERNOON. VSBY'S IMPROVING OVER FAR SOUTH SO EXPECT MAINLY MVFR/IFR CIGS AS MOISTURE LIFTS NORTH. OTHERWISE DEEP LAYERED RH HOLDS OFF UNTIL SECOND PERIOD SO NO EXPANSION OF PCPN PLANNED. STEADY WARM ADVECTION TODAY AND WITH PARTIAL/FILTERED SOLAR CURRENT TEMPERATURE FORECAST LOOKS REASONABLE WITH ANY CHANGES MINOR. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 540 AM CST SAT FEB 26 2005 .AVIATION... 9Z RUC HAS A GOOD HANDLE ON THE SHORT TERM WITH THE GFS/ETA BEING TOO SLOW. ISENTROPIC LIFT ABOVE 850 LOOKS PRETTY DECENT WITH THIS EVENT...AND EXPECT PREVAILING RAIN MUCH OF TODAY AND TONIGHT WITH RAIN BEGINNING IN ACT SOON AND AT METROPLEX TAF SITES BY 18Z. MOISTURE ADVECTION BELOW 850 IS RATHER WEAK...AND ALTHOUGH THE LOWER LEVELS WILL BE SATURATED DUE TO FALLING PRECIP...LATEST MAV/FWC MOS IS LIKELY TOO PESSIMISTIC WITH FORECASTING IFR CIGS. EXPECT JUST MVFR VIS/CIGS FOR DFW/DAL/FTW...BUT SLIGHTLY STRONGER NEAR SURFACE ISENTROPIC LIFT TO THE SOUTH WARRANTS TEMPO IFR AT ACT. HAVE NOT MENTIONED THUNDER BUT LATER SHIFTS WILL HAVE TO KEEP AN EYE ON THIS. EXPECT THE PASSAGE OF 700-850MB TROUGH AXIS AFTER 6Z WILL END PRECIP AND IMPROVE CONDITIONS TOWARD SUNRISE. TR/92 && .DISCUSSION... RADAR SHOWS THAT RAIN HAS DEVELOPED OVER SOUTH TEXAS OVERNIGHT...AND WAS MOVING INTO THE SOUTHERN MOST ZONES AS OF 10Z. RAIN WILL WILL CONTINUE TO INCREASE IN COVERAGE THIS MORNING AS ISENTROPIC UPGLIDE INCREASES ACROSS NORTH TEXAS. EXPECT RAINFALL AMOUNTS ACROSS THE SOUTH TO AVERAGE AROUND 1/2 INCH. WITH THE SATURATED GROUND...AND STREAMS AND SOME POINTS ON THE RIVERS HIGH...MORE RAIN COULD RESULT IN FLOODING. AT THIS TIME...BELIEVE THAT THE URBAN/SMALL STREAM FLOODING IS POSSIBLE...BUT FORECAST RAINFALL AMOUNTS ARE NOT ENOUGH FOR A FLOOD WATCH. THE RAIN WILL END FROM WEST TO EAST ON SUNDAY. THE DRY PERIOD WILL BE SHORT-LIVED...AS THE UPPER FLOW WILL BRING A SERIES OF UPPER LEVEL DISTURBANCES ACROSS NORTH TEXAS...RESULTING IN A CHANCE OF SHOWERS...AND MAYBE SOME THUNDERSTORMS...FROM TUESDAY MORNING THROUGH WEDNESDAY NIGHT. SOME UPPER LEVEL RIDGING IS THEN EXPECTED TO DEVELOP TO OUR WEST...WITH HEIGHTS GENERALLY RISING ACROSS NORTH TEXAS FOR THURSDAY AND FRIDAY. THE RIDGE WILL BREAK DOWN TOWARD THE END OF THE WEEKEND AS ANOTHER UPPER LOW MOVES INTO SOUTHERN CALIFORNIA. #58 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 57 42 58 41 / 60 80 30 10 WACO, TX 54 41 61 42 / 100 90 20 10 PARIS, TX 57 42 52 38 / 40 90 50 20 DENTON, TX 57 41 58 38 / 50 70 20 20 MCKINNEY, TX 58 42 57 38 / 50 80 30 20 DALLAS, TX 57 42 58 41 / 60 90 30 10 TERRELL, TX 57 43 57 40 / 60 90 30 10 CORSICANA, TX 56 43 58 41 / 80 90 30 10 TEMPLE, TX 52 41 62 42 / 100 90 20 10 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ 58/ tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 236 PM MST SAT FEB 26 2005 .SHORT TERM... (TONIGHT AND SUNDAY) MAIN SHORT TERM CONCERNS POPS. CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS INDICATING WEAK COLD CORE (-28C AT H5) UPPER LOW/TROUGH ACROSS CENTRAL COLORADO ...WITH FAST MOVING SHORT WAVE AND ASSOCIATED 80+ KT JET CORE DIVING OUT OF EASTERN BRITISH COLUMBIA ATTM. REGIONAL RADARS INDICATING RATHER SPRING LIKE CONVECTIVE PATTERN...WITH SCATTERED SHOWERS ACROSS THE HIGHER TERRAIN...SPREADING ACROSS THE HIGH MOUNTAIN VALLEYS AND ADJACENT PLAINS ATTM. TONIGHT...FAST MOVING SHORT WAVE ACROSS EASTERN BC CONTINUES TO MOVE ACROSS THE NORTHERN ROCKIES TONIGHT...WITH COLD CORE UPPER TROUGH SLIDING ACROSS EASTERN COLORADO AS UPPER FLOW BECOMES MORE NORTHERLY ALLOWING FOR WEAK COLD FRONT TO MOVE ACROSS THE PLAINS. WITH STEEP LAPSE RATES BETWEEN 7-8C/KM ACROSS THE REGION...WILL CONTINUE TO SEE SCATTERED SHOWERS ACROSS THE HIGHER TERRAIN WITH BEST COVERAGE ACROSS THE CENTRAL MTS THIS EVENING...WITH LOCAL ACCUMULATIONS OF A COUPLE OF INCHES UNDER THE HEAVIEST SHOWERS. HAVE KEPT ISOLATED SHOWERS ACROSS THE I-25 CORRIDOR THIS EVENING...WITH MAINLY VIRGA AND LOCALLY GUSTY WINDS EXPECTED WITH LOW LEVEL MOISTURE LACKING. CONVECTIVE SHOWERS ACROSS THE HIGHER TERRAIN SHOULD BE ON THE WANE AFTER SUNSET...THOUGH WILL KEEP ISOLATED TO SCATTERED POPS ACROSS THE CENTRAL MTS OVERNIGHT. ACROSS THE PLAINS...WEAK FRONTAL BOUNDARY MAKES ITS WAY TO THE PALMER DVD BETWEEN 9Z-12Z WITH GUSTY NORTHERLY WINDS OF 15 TO 25 MPH IN ITS WAKE. HAVE GONE WITH SCATTERED POPS ACROSS THE PIKES PEAK AND PALMER DVD REGION AFTER MIDNIGHT...WITH MODEL SOUNDINGS INDICATING SOME MID LEVEL MOISTURE AND ELEVATED INSTABILITY...ALONG WITH LIFT FROM FRONT...TO POP A FEW SHOWERS. SUNDAY...FRONTAL BOUNDARY CONTINUES TO MOVE ACROSS THE EASTERN PLAINS INTO EASTERN MEXICO EARLY SUNDAY MORNING...WITH MODELS CONTINUING TO PRINT OUT MODEST QPF ACROSS THE SOUTHERN SANGRES AND RATON MESA REGION. WITH NORTHERLY WIND COMPONENT OF 15-25KTS SFC- H7...ALONG WITH THE STEEP LAPSE RATES AND MID LEVEL MOISTURE...CANT ARGUE AND HAVE BUMPED POPS TO HIGH CHANCES FOR THIS AREA...KEEPING ACCUMULATIONS BETWEEN 1-3 INCHES. HAVE ALSO KEPT CHANCES ACROSS THE HIGHER TERRAIN WITH SLIGHT CHANCES ACROSS THE PLAINS THROUGH THE MORNING...WITH ONLY SLIGHT CHANCES ACROSS THE MAJORITY OF THE REGION SUNDAY AFTERNOON...AS MODELS INDICATING DRYING AND SUBSIDENCE WITH PASSING NORTHERN ROCKIES WAVE. WILL CONTINUE TO SEE GUSTY NORTHERLY WINDS ACROSS THE PLAINS THROUGH THE AFTERNOON...AND HAVE STAYED GENERALLY BETWEEN GUIDANCE TEMPS. -MW .LONG TERM... (MONDAY THROUGH SATURDAY) MON THROUGH WED...SOMEWHAT OF AN UNSETTLED WEATHER PATTERN... HOWEVER...BIG DIFFERENCE IN THE MODEL DATA. NORTHWEST FLOW CONTINUES SUN NGT INTO MON. THE GFS80...AS USUAL...IS MORE MOIST AND BLOWING UP A MID-LEVEL FRONTOGENETICAL FORCED IMPLIED ASCENT BAND OF PRECIPITATION...WHILE THE NAM DOESN'T REALLY REFLECT AS INTENSE OR WIDESPREAD PRECIPITATION EVENT. ALSO...THERE APPEARS TO BE ANOTHER SHORTWAVE TROUGH PROGGED TO MOVE OUT OF THE PACIFIC NORTHWEST AND INTO THE CNTRL ROCKIES BY TUE-WED. HOWEVER...AS USUAL...THE GFS80 IS VERY INTENSE WITH THE SHORTWAVE WHILE THE NAM/DGEX JUST HAVE A MINOR SHORTWAVE TROUGH AND LESS MOISTURE AND PRECIPITATION COVERAGE/INTENSITY. GIVEN PLENTY OF UNCERTAINTIES... WILL PLAN TO STICK WITH CURRENT FORECAST DATABASE. THU THROUGH SAT...WEAK-MOD MID/UPPER LEVEL RIDGE MOVES INTO THE ROCKIES WITH NORTHWEST FLOW ALOFT. THIS PATTERN WOULD GENERALLY PROMOTE POSSIBLE PRECIPITATION AROUND THE CONTINENTAL DIVIDE AND A MODERATING TEMP TREND AND BREEZY/WINDY CONDITIONS EAST OF THE DIVIDE. THE GFS80 HAS KIND OF A "CLIPPER" ULJ RACING OUT OF CANADA SAT INTO THE NRN ROCKIES AND PLAINS. THIS COULD BRING SOME UNSETTLED WEATHER BACK TO COLORADO FOR NEXT WEEKEND. AGAIN...GIVEN UNCERTAINTIES...WILL PLAN TO STICK WITH CURRENT FORECAST DATABASE AND BLEND BETTER WITH SURROUNDING OFFICES. [METZE] && .PUB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 23/17 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 1130 AM CST SAT FEB 26 2005 .AVIATION... BROKEN/OVERCAST VFR CIGS THAT ARE CURRENTLY REPORTED AT THE METROPLEX TAF SITES WILL RAPIDLY LOWER TO MVFR AROUND OR SHORTLY AFTER 27/00Z...AS -RA CONTINUES TO SATURATE THE STUBBORN WEDGE OF DRY AIR LOCATED WITHIN AND JUST ABOVE THE BOUNDARY LAYER. CIGS ARE ALREADY APPROACHING MVFR CRITERIA AT KACT...AND SHOULD FALL BELOW 3 KFT BETWEEN 26/18-21Z. BASED ON KFWS/KGRK REFLECTIVITY IMAGERY...AND SHORT TERM MODEL GUIDANCE...WILL CONTINUE MENTION OF -RA FOR ALL LOCATIONS...WITH ONLY A SLIGHT DELAY IN ONSET OF PRECIPITATION AT KDFW/KDAL. PRECIP SHOULD END AT ALL AIRPORTS BY 27/12Z...WITH CLEARING FROM SOUTHWEST TO NORTHEAST...AS UPPER TROUGH MOVES TO EAST OF THE AREA. LIGHT SOUTHEAST SURFACE WINDS WILL BECOME VARIABLE IN DIRECTION LATER THIS AFTERNOON...BUT SHOULD VEER TO SOUTHWEST BY LATE SUNDAY MORNING...AS SURFACE TROUGH ORGANIZES OVER THE HIGH PLAINS. 65/DD && .UPDATE... PER TRENDS ON RADAR/SATELLITE...HAVE INCREASED POPS TO CATEGORICAL WRN HALF OF N TX WITH LIKELY WORDING TO I-35 CORRIDOR FROM HILLSBORO TO THE RED RIVER. GENERALLY KEPT NE CORRIDOR (N I-20/E OF I-35 IN CHANCE CATEGORY FOR TODAY...WITH LIKELY/CATEGORICAL MORE INLINE FOR TONIGHT AND S/W AND WRN GULF INVERTED TROUGH HEAD ENE TOWARD THE LWR MS VALLEY. AS PREVIOUS SHIFT STATED...FLOOD WATCH WILL BE LOOKED AT CLOSELY FOR TONIGHT AT 4 PM ISSUANCE FOR ABOUT THE SE 1/3 OF N TX...BUT HELD OFF FOR NOW DESPITE LOW FFG VALUES AND SATURATED SOILS FOR A FEW REASONS. FOR ONE...TOTAL QPF NOT EXPECTED TO EXCEED AN INCH BASIN-WISE THROUGH TONIGHT...THOUGH ISOLATED AMOUNTS TO BETWEEN 0.5-0.75 ARE POSSIBLE THROUGH 12Z SUN. DISC WITH WGRFC/OTHERS INDICATES RIVER FLOOD RISK LOW ATTM. FINALLY...MORE GREENERY/ EVAPO-TRANSPIRATION POTENTIAL SHOULD HELP OUT AS WELL. THUS...ONLY EXPECT LOCALIZED...MINOR STREET/CREEK /STREAM TYPE PROBLEMS AT WORST WHICH CAN BE HANDLE BY SHORT TERM FCSTS AND ADVISORIES (FLS) IF NEEDED (THANKS TO EWX FOR COORD). OTHERWISE...PER COOLER TEMPS OUT WEST AND EXPECTED RAIN SHIELD MOST OF THE DAY...REDUCED HIGHS THAT REGION TO 47-50 WITH LOWER-MID 50S OVER THE FAR EAST WHERE RAIN SHOULD ARRIVE MORE TOWARD 21Z-00Z AND AFTER. MINOR ADJUSTMENTS ON TRENDS MADE TO WINDS/DEW PTS/ETC. 05/ && .AVIATION... 540 AM CST 09Z RUC HAS A GOOD HANDLE ON THE SHORT TERM WITH THE GFS/ETA BEING TOO SLOW. ISENTROPIC LIFT ABOVE 850 LOOKS PRETTY DECENT WITH THIS EVENT...AND EXPECT PREVAILING RAIN MUCH OF TODAY AND TONIGHT WITH RAIN BEGINNING IN ACT SOON AND AT METROPLEX TAF SITES BY 18Z. MOISTURE ADVECTION BELOW 850 IS RATHER WEAK...AND ALTHOUGH THE LOWER LEVELS WILL BE SATURATED DUE TO FALLING PRECIP...LATEST MAV/FWC MOS IS LIKELY TOO PESSIMISTIC WITH FORECASTING IFR CIGS. EXPECT JUST MVFR VIS/CIGS FOR DFW/DAL/FTW...BUT SLIGHTLY STRONGER NEAR SURFACE ISENTROPIC LIFT TO THE SOUTH WARRANTS TEMPO IFR AT ACT. HAVE NOT MENTIONED THUNDER BUT LATER SHIFTS WILL HAVE TO KEEP AN EYE ON THIS. EXPECT THE PASSAGE OF 700-850MB TROUGH AXIS AFTER 6Z WILL END PRECIP AND IMPROVE CONDITIONS TOWARD SUNRISE. TR/92 PREV DISCUSSION... 325 AM CDT RADAR SHOWS THAT RAIN HAS DEVELOPED OVER SOUTH TEXAS OVERNIGHT...AND WAS MOVING INTO THE SOUTHERN MOST ZONES AS OF 10Z. RAIN WILL WILL CONTINUE TO INCREASE IN COVERAGE THIS MORNING AS ISENTROPIC UPGLIDE INCREASES ACROSS NORTH TEXAS. EXPECT RAINFALL AMOUNTS ACROSS THE SOUTH TO AVERAGE AROUND 1/2 INCH. WITH THE SATURATED GROUND...AND STREAMS AND SOME POINTS ON THE RIVERS HIGH...MORE RAIN COULD RESULT IN FLOODING. AT THIS TIME...BELIEVE THAT THE URBAN/SMALL STREAM FLOODING IS POSSIBLE...BUT FORECAST RAINFALL AMOUNTS ARE NOT ENOUGH FOR A FLOOD WATCH. THE RAIN WILL END FROM WEST TO EAST ON SUNDAY. THE DRY PERIOD WILL BE SHORT-LIVED...AS THE UPPER FLOW WILL BRING A SERIES OF UPPER LEVEL DISTURBANCES ACROSS NORTH TEXAS...RESULTING IN A CHANCE OF SHOWERS...AND MAYBE SOME THUNDERSTORMS...FROM TUESDAY MORNING THROUGH WEDNESDAY NIGHT. SOME UPPER LEVEL RIDGING IS THEN EXPECTED TO DEVELOP TO OUR WEST...WITH HEIGHTS GENERALLY RISING ACROSS NORTH TEXAS FOR THURSDAY AND FRIDAY. THE RIDGE WILL BREAK DOWN TOWARD THE END OF THE WEEKEND AS ANOTHER UPPER LOW MOVES INTO SOUTHERN CALIFORNIA. #58 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ /05 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1040 AM CST SAT FEB 26 2005 .UPDATE... PER TRENDS ON RADAR/SATELLITE...HAVE INCREASED POPS TO CATEGORICAL WRN HALF OF N TX WITH LIKELY WORDING TO I-35 CORRIDOR FROM HILLSBORO TO THE RED RIVER. GENERALLY KEPT NE CORRIDOR (N I-20/E OF I-35 IN CHANCE CATEGORY FOR TODAY...WITH LIKELY/CATEGORICAL MORE INLINE FOR TONIGHT AND S/W AND WRN GULF INVERTED TROUGH HEAD ENE TOWARD THE LWR MS VALLEY. AS PREVIOUS SHIFT STATED...FLOOD WATCH WILL BE LOOKED AT CLOSELY FOR TONIGHT AT 4 PM ISSUANCE FOR ABOUT THE SE 1/3 OF N TX...BUT HELD OFF FOR NOW DESPITE LOW FFG VALUES AND SATURATED SOILS FOR A FEW REASONS. FOR ONE...TOTAL QPF NOT EXPECTED TO EXCEED AN INCH BASIN-WISE THROUGH TONIGHT...THOUGH ISOLATED AMOUNTS TO BETWEEN 0.5-0.75 ARE POSSIBLE THROUGH 12Z SUN. DISC WITH WGRFC/OTHERS INDICATES RIVER FLOOD RISK LOW ATTM. FINALLY...MORE GREENERY/ EVAPO-TRANSPIRATION POTENTIAL SHOULD HELP OUT AS WELL. THUS...ONLY EXPECT LOCALIZED...MINOR STREET/CREEK /STREAM TYPE PROBLEMS AT WORST WHICH CAN BE HANDLE BY SHORT TERM FCSTS AND ADVISORIES (FLS) IF NEEDED (THANKS TO EWX FOR COORD). OTHERWISE...PER COOLER TEMPS OUT WEST AND EXPECTED RAIN SHIELD MOST OF THE DAY...REDUCED HIGHS THAT REGION TO 47-50 WITH LOWER-MID 50S OVER THE FAR EAST WHERE RAIN SHOULD ARRIVE MORE TOWARD 21Z-00Z AND AFTER. MINOR ADJUSTMENTS ON TRENDS MADE TO WINDS/DEW PTS/ETC. 05/ && .AVIATION... 540 AM CST 09Z RUC HAS A GOOD HANDLE ON THE SHORT TERM WITH THE GFS/ETA BEING TOO SLOW. ISENTROPIC LIFT ABOVE 850 LOOKS PRETTY DECENT WITH THIS EVENT...AND EXPECT PREVAILING RAIN MUCH OF TODAY AND TONIGHT WITH RAIN BEGINNING IN ACT SOON AND AT METROPLEX TAF SITES BY 18Z. MOISTURE ADVECTION BELOW 850 IS RATHER WEAK...AND ALTHOUGH THE LOWER LEVELS WILL BE SATURATED DUE TO FALLING PRECIP...LATEST MAV/FWC MOS IS LIKELY TOO PESSIMISTIC WITH FORECASTING IFR CIGS. EXPECT JUST MVFR VIS/CIGS FOR DFW/DAL/FTW...BUT SLIGHTLY STRONGER NEAR SURFACE ISENTROPIC LIFT TO THE SOUTH WARRANTS TEMPO IFR AT ACT. HAVE NOT MENTIONED THUNDER BUT LATER SHIFTS WILL HAVE TO KEEP AN EYE ON THIS. EXPECT THE PASSAGE OF 700-850MB TROUGH AXIS AFTER 6Z WILL END PRECIP AND IMPROVE CONDITIONS TOWARD SUNRISE. TR/92 PREV DISCUSSION... 325 AM CDT RADAR SHOWS THAT RAIN HAS DEVELOPED OVER SOUTH TEXAS OVERNIGHT...AND WAS MOVING INTO THE SOUTHERN MOST ZONES AS OF 10Z. RAIN WILL WILL CONTINUE TO INCREASE IN COVERAGE THIS MORNING AS ISENTROPIC UPGLIDE INCREASES ACROSS NORTH TEXAS. EXPECT RAINFALL AMOUNTS ACROSS THE SOUTH TO AVERAGE AROUND 1/2 INCH. WITH THE SATURATED GROUND...AND STREAMS AND SOME POINTS ON THE RIVERS HIGH...MORE RAIN COULD RESULT IN FLOODING. AT THIS TIME...BELIEVE THAT THE URBAN/SMALL STREAM FLOODING IS POSSIBLE...BUT FORECAST RAINFALL AMOUNTS ARE NOT ENOUGH FOR A FLOOD WATCH. THE RAIN WILL END FROM WEST TO EAST ON SUNDAY. THE DRY PERIOD WILL BE SHORT-LIVED...AS THE UPPER FLOW WILL BRING A SERIES OF UPPER LEVEL DISTURBANCES ACROSS NORTH TEXAS...RESULTING IN A CHANCE OF SHOWERS...AND MAYBE SOME THUNDERSTORMS...FROM TUESDAY MORNING THROUGH WEDNESDAY NIGHT. SOME UPPER LEVEL RIDGING IS THEN EXPECTED TO DEVELOP TO OUR WEST...WITH HEIGHTS GENERALLY RISING ACROSS NORTH TEXAS FOR THURSDAY AND FRIDAY. THE RIDGE WILL BREAK DOWN TOWARD THE END OF THE WEEKEND AS ANOTHER UPPER LOW MOVES INTO SOUTHERN CALIFORNIA. #58 && .FWD WATCHES/WARNINGS/ADVISORIES... TX...NONE. && $$ /05 tx