Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/14/13


AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
145 PM EST SAT JAN 12 2013 .SYNOPSIS... 18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A HIGHLY AMPLIFIED PATTERN IN PLACE OVER THE CONUS. LUCKILY FOR US...THE WARM AND FAIR WEATHER SIDE OF THIS AMPLIFICATION RESIDES OVER OUR HEADS...AND WILL CONTINUE TO DO SO FOR THE REMAINDER OF THE WEEKEND. LARGE SCALE PATTERN CONSISTS OF DEEP LONGWAVE TROUGHING IN PLACE OVER THE WESTERN HALF OF THE NATION FOLLOWED DOWNSTREAM BY LONGWAVE RIDGING EXTENDING FROM THE EASTERN GULF OF MEXICO NORTHWARD ALONG THE ENTIRE EASTERN SEABOARD. WV IMAGERY CONTINUES TO SHOW AN INTERESTING SPIN / LEFTOVER MCV PUSHING THROUGH THE RIDGE OFF THE NORTHEAST FL COAST. THIS VORTICITY CENTER IS LIKELY LEFTOVER FROM CONVECTION TO OUR WEST DURING THE PAST COUPLE DAYS. THIS FEATURE IS VISUALLY INTERESTING... BUT WILL HAVE LITTLE IMPACT ON OUR LOCAL WEATHER OTHER THAN SOME WEAK NVA/ENHANCE SUPPRESSION OVER THE AREA THROUGH THE AFTERNOON. 12Z KTBW SOUNDING PROFILE SHOWS THE INFLUENCE OF THE UPPER RIDGE WITH A DISTINCT SUBSIDENCE INVERSION ABOVE 850MB. COLUMN IS QUITE DRY ABOVE THIS LEVEL...BUT SEEING ENOUGH MOISTURE UNDERNEATH TO ONCE AGAIN FORCE A SCT-BKN SHALLOW CU FIELD OVER LAND AREAS THROUGH EARLY THIS EVENING. AT THE SURFACE...HIGH PRESSURE CENTERED OFF THE SOUTHEAST COAST RIDGES BACK TO THE WEST ALONG OR JUST NORTH OF THE I-10 CORRIDOR. THIS POSITION CONTINUES TO PROVIDE OUR LOCAL AREA WITH A LIGHT EAST TO EAST-SOUTHEAST FLOW. THE UNSEASONABLE TEMPERATURES ALSO CONTINUE WITH MANY LOCATION ALREADY REPORTING READINGS IN THE LOWER 80S. IT IS QUITE POSSIBLE THAT A FEW MORE RECORD HIGHS WILL BE BROKEN THIS AFTERNOON. && .SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)... TONIGHT THROUGH SUNDAY NIGHT... STACKED RIDGING WILL KEEP THE WEATHER PATTERN UNCHANGED THROUGH THE REMAINDER OF THE WEEKEND. OVERNIGHT LOWS WILL MAINLY BE IN THE LOWER/MID 60S AT THE COAST AND MIDDLE 50S TO AROUND 60 INLAND. DAYTIME HIGHS CLIMB BACK INTO THE LOWER 80S FOR MANY LOCATIONS SUNDAY AFTERNOON. LOCAL GRADIENT DOES SLACKEN A BIT DURING THE DAY ON SUNDAY...AND DUE TO THE UNUSUALLY STRONG LAND BASED HEATING...MAY SEE A FEEBLE SEA-BREEZE DEVELOP DURING THE AFTERNOON...ESPECIALLY FROM PINELLAS COUNTY NORTHWARD WHERE THE LAND/SEA TEMPERATURE GRADIENT WILL BE GREATEST. IF THIS WEAK ONSHORE FLOW DOES DEVELOP THEN THE IMMEDIATE COAST WOULD END UP A FEW DEGREES COOLER. REGARDLESS WILL BE FORECASTING ABOVE NORMAL TEMPERATURES FOR ALL. THE UPPER LEVEL RIDGE OVER-TOP THE INFLUX OF LOW LEVEL ATLANTIC MOISTURE IS A GOOD SETUP FOR AREAS OF FOG TO DEVELOP ONCE AGAIN DURING THE LATE NIGHT HOURS...SIMILAR TO EARLY THIS MORNING. BEST CHANCES FOR THE FOG WILL BE INLAND. SHELF WATER TEMPERATURES HAVE WARMED BY SEVERAL DEGREES DURING THE PAST WEEK RESULTING IN LESS POTENTIAL FOR ADVECTION SEA FOG. HOWEVER...WILL CONTINUE TO MONITOR FOR THIS POSSIBILITY...ESPECIALLY ALONG THE NATURE COAST ZONES. MONDAY/MONDAY NIGHT... WARM AND GENERALLY DRY CONDITIONS PREVAIL INTO THE FIRST DAY OF THE NEW WORK WEEK AS STACKED RIDGING WILL REMAIN IN PLACE. WILL BEGIN TO SEE THE FIRST SIGNS OF THE EVENTUAL BREAK DOWN OF THE RIDGE BY MONDAY NIGHT INTO TUESDAY AS HEIGHT FALLS BEGIN TO SPREAD ACROSS THE SOUTHERN PLAINS AND MIDDLE MS VALLEY. THIS PATTERN WILL EVENTUALLY PUSH THE UPPER RIDGE EASTWARD AND ALLOW A FRONT TO SLIP INTO OUR REGION...BUT THIS IS NOT UNTIL THE MID-WEEK PERIOD. MORE ON THIS FRONT IN THE LONG TERM DISCUSSION BELOW. && .LONG TERM (TUESDAY - FRIDAY)... AN UPPER LEVEL TROUGH REACHES FROM HUDSON BAY TO THE SOUTHWEST U.S. WITH A FRONT FROM THE GREAT LAKES TO THE WESTERN GULF COAST WHILE DEEP RIDGING OFF THE EASTERN SEABOARD EXTENDS TO THE EAST GULF AND CUBA MON NIGHT. THE UPPER TROUGH SLOWLY WORKS EAST TO THE EASTERN STATES BY WED...SHIFTING THE DEEP RIDGING TO ALONG AND SOUTH OF LATITUDE 30 NORTH. THE FRONT SAGS ACROSS THE GULF COAST AND SE U.S. AND PUSHES INTO FL LATE WED. THIS WOULD SUGGEST SOME POSSIBILITY OF RAINFALL BUT BOTH MOISTURE AND ENERGY ARE LIMITED AND WILL KEEP THE FORECAST DRY. THU-FRI...WHILE THE GFS AND ECMWF HAVE BEEN IN FAIRLY GOOD AGREEMENT THEY NOW BEGIN TO DIVERGE. THE GFS KEEPS BROAD TROUGHING OVER THE EASTERN U.S. AS A SURFACE HIGH MOVES OVER THE GULF COASTAL STATES TO THE ATLANTIC. THIS PATTERN WOULD KEEP THE AREA DRY AND STABLE. THE ECMWF HAS SIMILAR TROUGHING BUT WITH A CUT-OFF LOW OVER THE SOUTHERN PLAINS THAT MOVES TO THE CENTRAL GULF COAST WITH AN ASSOCIATED SURFACE LOW THAT TRAILS A COLD FRONT ACROSS THE CENTRAL AND EASTERN GULF. THIS WOULD SUGGEST SOME BETTER...BUT LOW...ODDS OF PRECIPITATION. FOR NOW WILL MAINTAIN A DRY FORECAST. INITIALLY WARM TEMPERATURES WILL GRADUALLY DECREASE BUT STILL REMAIN ABOVE NORMAL. && .AVIATION... SOME CHANCE OF BRIEF MVFR CEILINGS AROUND 3000 FEET THIS AFTERNOON...BUT MAINLY BROKEN VFR CEILINGS 3500 TO 5000 FEET. FOG AND LOW CLOUDS DEVELOP 06-09Z WITH MVFR TO IFR POSSIBLE ALL TERMINALS AND LIFR POSSIBLE LAL AND PGD. && .MARINE... THE SURFACE RIDGE REMAINS ALIGNED FROM OFF THE SOUTHEAST COAST BACK WESTWARD ALONG THE I-10 CORRIDOR. THE RIDGE WILL HOLD POSITION THROUGH TONIGHT AND THEN SLOWLY SETTLE SOUTHWARD LATER SUNDAY INTO THE EARLY PORTION OF NEXT WEEK. NO MARINE HEADLINES ARE ANTICIPATED THROUGH THE EARLY PORTION OF THE WEEK. THE NEXT COLD FRONT IS EXPECTED TO ARRIVE ACROSS THE EASTERN GULF OF MEXICO BY WEDNESDAY OR WEDNESDAY NIGHT. && .FIRE WEATHER... SURFACE AND UPPER LEVEL HIGH PRESSURE WILL REMAIN IN CONTROL OF THE FORECAST AREA THROUGH MONDAY KEEPING OUR WEATHER GENERALLY DRY WITH ABOVE AVERAGE TEMPERATURES. DESPITE THE WARM DAYTIME TEMPERATURES... THE SURFACE RIDGE POSITION OFF THE SOUTHEAST COAST WILL PROVIDE A STEADY INFLUX OF LOW LEVEL ATLANTIC MOISTURE AND PREVENT ANY WIDESPREAD AREAS OF CRITICALLY LOW RELATIVE HUMIDITY. THE NEXT COLD FRONT IS NOT ANTICIPATED TO ARRIVE UNTIL LATER WEDNESDAY OR WEDNESDAY NIGHT. A MORE SEASONABLE AIRMASS IS ANTICIPATED TO ARRIVE BEHIND THIS FRONT FOR THE LATER PORTION OF NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... TPA 64 81 64 80 / 0 0 10 0 FMY 64 83 62 82 / 0 0 0 0 GIF 59 82 58 82 / 0 0 0 0 SRQ 62 79 60 79 / 0 0 0 0 BKV 57 83 55 81 / 0 0 10 0 SPG 65 79 64 78 / 0 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA AVIATION...JILLSON LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
955 AM EST SAT JAN 12 2013 .UPDATE (REST OF THE WEEKEND)... 15Z WATER VAPOR AND H4 RAP ANALYSIS SHOW A HIGHLY AMPLIFIED PATTERN IN PLACE OVER THE CONUS THIS MORNING. LUCKILY FOR US...THE WARM AND FAIR WEATHER SIDE OF THIS AMPLIFICATION RESIDES OVER OUR HEADS...AND WILL CONTINUE TO DO SO FOR THE REMAINDER OF THE WEEKEND. LARGE SCALE PATTERN CONSISTS OF DEEP LONGWAVE TROUGHING IN PLACE OVER THE WESTERN HALF OF THE NATION FOLLOWED DOWNSTREAM BY LONGWAVE RIDGING EXTENDING FROM THE EASTERN GULF OF MEXICO NORTHWARD ALONG THE ENTIRE EASTERN SEABOARD. WV IMAGERY SHOWS AN INTERESTING SPIN / LEFTOVER MCV RUNNING THROUGH THE RIDGE THIS MORNING OVER NORTHERN FLORIDA...LIKELY LEFTOVER FROM CONVECTION TO OUR WEST DURING THE PAST COUPLE DAYS. THIS FEATURE IS VISUALLY INTERESTING...BUT WILL HAVE LITTLE IMPACT ON OUR LOCAL WEATHER OTHER THAN SOME WEAK NVA/ENHANCE SUPPRESSION OVER THE AREA INTO THE EARLY AFTERNOON. THIS SUPPRESSION OVER-TOP THE LOW LEVEL MOISTURE MAY HAVE AIDED SOME OF THE FOG FORMATION EARLIER THIS MORNING...BUT NOW THAT DIURNAL HEATING HAS COMMENCED...ANY LEFTOVER VISIBILITY RESTRICTIONS WILL SOON BE A DISTANT MEMORY. 12Z KTBW SOUNDING PROFILE SHOWS THE INFLUENCE OF THE UPPER RIDGE WITH A DISTINCT SUBSIDENCE INVERSION ABOVE 850MB THIS MORNING. COLUMN IS QUITE DRY ABOVE THIS LEVEL...BUT SEEING ENOUGH MOISTURE UNDERNEATH TO ONCE AGAIN FORCE A SCT-BKN SHALLOW CU FIELD FOR THE AFTERNOON HOURS. MADE A FEW TWEAKS TO THE AFTERNOON TEMPERATURE CURVE AND SKY COVER GRIDS...BUT OTHERWISE INHERITED FORECAST APPEARS ON TRACK FOR ANOTHER FAIR AND UNSEASONABLY WARM JANUARY DAY. TONIGHT/SUNDAY...STACKED RIDGING WILL KEEP THE WEATHER PATTERN UNCHANGED THROUGH THE REMAINDER OF THE WEEKEND. OVERNIGHT LOWS WILL MAINLY BE IN THE LOWER/MID 60S AT THE COAST AND MIDDLE 50S TO AROUND 60 INLAND BY SUNRISE. DAYTIME HIGHS CLIMB BACK INTO THE LOWER 80S FOR MANY LOCATIONS SUNDAY AFTERNOON. LOCAL GRADIENT DOES SLACKEN A BIT DURING THE DAY ON SUNDAY...AND DUE TO THE UNUSUALLY STRONG LAND BASED HEATING...MAY SEE A FEEBLE SEA-BREEZE DEVELOP DURING THE AFTERNOON...ESPECIALLY FROM PINELLAS COUNTY NORTHWARD. IF THIS WEAK ONSHORE FLOW DOES DEVELOP THEN THE IMMEDIATE COAST WOULD END UP A FEW DEGREES COOLER. REGARDLESS WILL BE FORECASTING ABOVE NORMAL TEMPERATURES FOR ALL. && .AVIATION... EXPECT VFR CONDITIONS WITH OCNL BROKEN CIGS ABOVE 3000 FEET THROUGH 08Z. MVFR OR IFR VISIBILITIES IN FOG POSSIBLE AFTER 08Z SUNDAY. && .MARINE... SURFACE HIGH PRESSURE OFFSHORE OF THE SOUTHEAST U.S. WILL REMAIN IN PLACE THROUGH EARLY NEXT WEEK WITH A SOUTHEAST WIND FLOW CONTINUING. THIS HIGH WILL SHIFT SOUTH AND EAST OF THE REGION ON TUESDAY AS A COLD FRONT MOVES INTO THE NORTHERN GULF WATERS. THIS FRONT WILL THEN MOVE SOUTH THROUGH THE WATERS ON WEDNESDAY SHIFTING WINDS TO THE NORTHWEST AND NORTH IN ITS WAKE. && .CLIMATE... HERE ARE SOME RECORD HIGH TEMPERATURES FOR TODAY. TAMPA INTERNATIONAL 82 SET BACK IN 1989 SAINT PETERSBURG CLEARWATER 81 SET BACK IN 2005 SARASOTA/BRADENTON 86 SET BACK IN 1993 LAKELAND 85 SET BACK IN 1993 BROOKSVILLE 81 SET BACK IN 2008 FORT MYERS 85 SET BACK IN 1993 && .PRELIMINARY POINT TEMPS/POPS... TPA 82 64 81 65 / 0 10 0 10 FMY 83 63 82 62 / 0 10 0 0 GIF 82 61 82 62 / 0 10 0 10 SRQ 80 62 80 61 / 0 10 0 10 BKV 83 55 82 55 / 0 10 0 10 SPG 79 65 79 65 / 0 10 0 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/MARINE...MROCZKA AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
528 AM EST SAT JAN 12 2013 .SHORT TERM... /TODAY THROUGH SUNDAY NIGHT/ HIGHLY COMPLEX MID/UPR TROPOSPHERIC WAVE INTERACTIONS/DEFORMATIONS UNDERWAY ACRS UPR PLAINS BLIZZARD/SNOWSTORM IN PROGRESS. HIGHLY BUCKLED FLOW PATTERN PER RIDGE AXIS ALONG WRN ATL AND 140W. THIS ALONG WITH STRONGLY MERIDIONAL FLOW DOWNSTREAM OF INTMTN/CNTL ROCKIES TROF WITH NMRS SHORTWAVES TRANSLATING THROUGH...FIRST EJECTING FM NRN OLD MEXICO ATTM AND OTHER SIG WAVE ACRS WRN ALB TO HELP REPLANT BASE ACRS THE SWRN STATES THROUGH THE SHORT TERM PD...AFFORDING STRONG PERMANENCE IN THE SHORT TERM WITH A PRIMARILY STRONG POS TILT TROF AXIS...PRESENTING AS A SLOW/STALLED EULARIAN STREAM SYSTEM WITH EMBEDDED HIGH VELOCITY LAGRANGIAN SUBSCALE FEATURES. GIVEN PRECONDITIONING WITH DEEP SRLY/SWRLY FLOW DOWNSTREAM TO PROVIDE QUITE SECURE WARM/HIGH BULK MOISTURE AIRMASS /PWAT AOA 1.25-1.4 INCHES/ INTO SRN GRTLKS/OHIO VALLEY...WITH CONTINUAL LLVL GOMEX SUSTENANCE FEED BENEATH SUBTROPICAL MOISTURE SWEEP IN THE MID/UP LVLS. SRN TAIL OF NRN PLAINS UPSTREAM SFC FNTL WAVE TO APPROACH LATE TODAY...THOUGH IN A STRONGLY LYTIC FASHION ALONG ITS SRN EXTENSION WITH BEST DEEPLY FORCED ASCENT HELD AT ABEYANCE WELL N/NW OF CWA. SLIGHT DELAY IN ONSET OF PRECIP ASSOCD WITH TIMING OF SWRN TX FNTL WAVE TONIGHT...CERTAINLY NOT WRT REVERSAL OF TROF TILT. SFC LOW ACRS CNTL ARKANSAS AT F24...THEN QUICKLY INTO WRN LK ERIE BY 12 UTC SUN. STRONG FGEN RESPONSE AMID WARM/MOIST AIRMASS TO RESULT IN LARGE RAIN SWATH. SOME CONCERN WRT NEED OF FLOOD WATCH FOR MAUMEE AND WABASH BASINS...HOWEVER ATTM SPEED OF SYSTEM ALONG WITH STRONG INDICATIONS OF QUICK TAPER DURING THE DAY SUNDAY. FOR NOW WITH PRIOR RAFL/RUNOFF RESPONSES BEING RELATIVELY MUTED...WILL SIMPLY ADDRESS IN ESF/HWO. A SFC LOW TRACK POTNL THROUGH HEART AFOREMENTIONED BASINS GIVES DISFAVOR FOR SECONDARY DEFORMATION ZONE ENHANCED PRECIP SWATCH. AGAIN POSTFNTL UNDERCUT OF COLD AIR /DEPTH MAGNITUDE AND POSITION/ OF DIRE IMPORTANCE WRT PTYPE. QUICK/ARDENT LOSS OF MSTR/SATURATION DEPTH IN DRY SLOT PERHAPS SAVING GRACE AS ANTICIPATE WINTRY MIX ACCUMS AOB HEADLINES AND/OR INCRSLY CONDITIONAL IN NATURE. WL CERTAINLY ADDRESS POTNL/IN HWO. MUTED LAKE RESPONSE WITH STRONGLY SHEARED IN CLOUD FLOW THAT QUICKLY BACKS WRLY...SUPPORTING A SUBVERSIVE DRY UNDERCUT TO ANY BANDS AS CANADIAN/PLAINS AIRMASS BEGINS TO QUICKLY BECOME ENTRAINED THROUGH WI/SRN LK MI SUN EVE/NIGHT. DEPTH OF MSTR ALSO NEGATIVE WITH DGZ FAILURE NOTED...PERHAPS EVEN AN ICE CRYSTAL NUCLAETION FAILURE PSBLTY SUNDAY AFTN. ABOVE FACTORS OVERLAIN WITH OVERALL LAME LAKE INDUCED THERMAL STABILITY...SUGGESTS LOW CHC SHSN AND/OR SCT FLURRIES MENTION BEST ATTM. && .LONG TERM...MONDAY THROUGH FRIDAY. N/NW FLOW WILL HOLD THROUGH THE PERIOD WITH TEMPS NEAR OR BELOW NORMAL. INITIALLY...DELTA T`S FAVORABLE FOR SOME LAKE EFFECT CLOUD AND SNOW SHOWERS. HOWEVER...MSTR PROFILES QUITE ANEMIC AND WHAT DOES EXIST IS MAINLY CONFINED NORTH OF THE FORECAST AREA. HAVE NUDGED POPS UP TO 14 PERCENT ACROSS MI COUNTIES BUT NO INTRODUCTION OF ANY WX MENTION AT THIS POINT. A SERIES OF WEAK WAVES WILL MOVE THROUGH THE FLOW...IMPACTING MAINLY THE NORTHERN PLAINS/GREAT LAKES AREAS. EACH WAVE WILL ATTEMPT TO REINFORCE THE COLD AIR ACROSS THE REGION. MODELS VARY ON HOW FAR SOUTH EACH OF THESE INTRUSIONS WILL BE. AT THIS POINT...FEW CHANGES TO PAST GRIDS. ALLBLEND CONTINUES TO PLACE IN SLGT CHC POPS WITH EACH WAVE...BUT WITH LESS THAN FAVORABLE TRACK FOR THE AREA SEE NO REASON TO MESS UP GRIDS WITH SEVERAL PERIODS OF SLGT CHCS. TEMPS WILL ATTEMPT TO MODERATE SOMEWHAT AT LEAST BACK TOWARDS NORMAL THROUGH THE PERIOD. POINT OF INTEREST...POLAR VORTEX WILL BEGIN ITS SLOW MIGRATION SOUTH INTO HUDSON BAY THROUGH THE UPCOMING WEEK. WHILE MODELS HAVE BEEN ADVERTISING ON AND OFF FOR SEVERAL WEEKS OF A ARCTIC INTRUSION DROPPING INTO THE LAKES THIS HAS LARGELY NOT COME TO FRUITION AS OF YET. 00Z RUNS OF EURO AND GFS BOTH IN GENERAL AGREEMENT ON LARGE PIECE OF THIS VORTEX DROPPING SOUTH ENOUGH TO IMPACT THE AREA WITH -28 C OR COLDER TEMPS DROPPING THROUGH THE WESTERN GREAT LAKES TOWARDS THE FORECAST AREA. AS ALWAYS...CONFIDENCE IN ANY MODEL 240 HOURS OUT VERY VERY LOW...SOMETHING TO MONITOR TREND WISE OVER THE NEXT WEEK. && .AVIATION... /06 UTC TAFS/ PRIME FOCUS ON CURRENT/NEXT HAZARDS...LLWS/RAIN RESPECTIVELY. SLIGHT ADJUSTMENTS TO SLIGHTLY MORE VEERED LLJ PER PRESENT UPSTREAM VWP/PROFILER DATA AND RAP ANALYSIS. FOCUS FOR RENEWED LIFT IN WARM/ABNORMALLY MOIST ENVIRONMENT COMMENCES LATE TONIGHT AND HAVE INTRODUCED DOWNWARD TREND. SUSPECT HIR PROB FOR MORE WIDESPREAD IFR MET CONDS TO BE REALIZED WITH TIME/BY 12 UTC SUN ACRS NRN IN...AND TO BE ASSESSED IN LATER FCSTS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST MONDAY FOR LMZ043-046. && $$ SHORT TERM...MURPHY LONG TERM...FISHER AVIATION...MURPHY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
100 AM EST SAT JAN 12 2013 .AVIATION... /06 UTC TAFS/ PRIME FOCUS ON CURRENT/NEXT HAZARDS...LLWS/RAIN RESPECTIVELY. SLIGHT ADJUSTMENTS TO SLIGHTLY MORE VEERED LLJ PER PRESENT UPSTREAM VWP/PROFILER DATA AND RAP ANALYSIS. FOCUS FOR RENEWED LIFT IN WARM/ABNORMALLY MOIST ENVIRONMENT COMMENCES LATE TONIGHT AND HAVE INTRODUCED DOWNWARD TREND. SUSPECT HIR PROB FOR MORE WIDESPREAD IFR MET CONDS TO BE REALIZED WITH TIME/BY 12 UTC SUN ACRS NRN IN...AND TO BE ASSESSED IN LATER FCSTS. && .UPDATE... LINGERING STRATOCU HAS LIFTED NORTHWARD ACROSS SOUTHERN LOWER MICHIGAN THIS EVENING WITH MAINLY HIGH LEVEL CLOUDINESS PERSISTING ACROSS THE AREA. THE COMBINATION OF CONTINUED HIGH LEVEL CLOUDS OVERNIGHT AND MODERATE GRADIENT PERSISTING SHOULD ALLOW FOR MINIMAL TEMP DROPS FOR THE REMAINDER OF THE NIGHT. DESPITE GRADIENT...SURFACE OBSERVATIONS ACROSS THE REGION INDICATING SOME FAIRLY GOOD DECOUPLING EARLIER THIS EVENING WHICH HAVE ALLOWED TEMPS TO DROP INTO THE MID AND UPPER 40S ACROSS NORTHERN PORTIONS OF THE AREA. A FEW MORE DEGREES OF TEMPERATURE DROP ARE POSSIBLE THIS EVENING...BEFORE A MORE STEADY TEMPERATURE TREND BECOMES ESTABLISHED OVERNIGHT AS LOW LEVEL JET STRENGTHENS PLACING LOCAL AREA IN MORE ROBUST WARM SECTOR ONCE AGAIN. SOME MINOR TWEAKS MADE TO HOURLY TEMPERATURE CURVE TO ACCOUNT FOR EARLIER EVENING DECOUPLING...BUT PREVIOUS FORECAST APPEARS TO BE IN GOOD SHAPE. && .PREV DISCUSSION... /ISSUED 335 PM EST FRI JAN 11 2013/ SHORT TERM.../TONIGHT THROUGH SATURDAY NIGHT/ BALMY MID JANUARY WX IS EXPECTED TO CONTINUE INTO TONIGHT AND SATURDAY...WITH ANOTHER ROUND OF RAIN (MIXING WITH SLEET/FREEZING RAIN WESTERN AREAS) SATURDAY NIGHT... DEEP SOUTHWESTERLY FLOW IN ADVANCE OF A DEEP WESTERN CONUS FULL LATITUDE UPPER TROUGH WILL KEEP TEMPS UNUSUALLY MILD TONIGHT INTO TOMORROW AS WARM SECTOR HAS BUILT IN BEHIND LAST NIGHTS LEAD WAVE AND WARM FRONT. LOWS TONIGHT WILL BE AN IMPRESSIVE ~30F ABOVE NORMAL WITH HIGHS ~25F ABOVE NORMAL TOMORROW. ATTENTION THEN TURNS TO QPF/PTYPE OF PCPN PROGGED TO IMPACT THE ENTIRE AREA SATURDAY NIGHT. LEAD WAVE OF LOW PRESSURE TRACKING NORTHEAST THROUGH THE UPPER MIDWEST AND INTO ONTARIO TONIGHT INTO SATURDAY WILL FORCE A SFC FRONTAL BOUNDARY SOUTHEAST INTO SOUTHEASTERN PORTIONS OF OUR FA BY SATURDAY AFTERNOON/EVENING...STALLING OUT HERE UNDER SOUTHWEST FLOW ALOFT. A FRONTAL WAVE WILL DEVELOP ALONG THIS STALLED FRONT AS SHEARED SHORTWAVE ENERGY NOW JUST OFF THE SOUTHERN CALIFORNIA COAST ROUNDS THE BASE OF THE DEEP WESTERN CONUS TROUGH AND PROPAGATES NORTHEAST INTO THE MID MS VALLEY AND GREAT LAKES. MODERATE TO HEAVY RAIN SHOULD BLOSSOM ALONG THE DEEPENING FRONTAL CIRCULATION WITH A STRONG AGEOSTROPHIC RESPONSE ANTICIPATED UNDER THE RIGHT ENTRANCE REGION OF A 160 KT UPPER JET. THIS COMBINED WITH AN OPEN GULF OF MEXICO AND DECREASED STABILITY (MODELS DEPICTING -EPV AND THETA-E FOLDING ON XSECTIONS JUST ABOVE THE FRONTAL INVERSION) HINTS AT A CONVECTIVE ELEMENT WITH A NARROW AXIS OF 1-2 INCH RAINFALL TOTALS POSSIBLE INTO NE INDIANA AND NW OHIO. THIS COULD LEAD TO SOME MINOR HYDRO RELATED PROBLEMS...CHECK ESFIWX (HYDROLOGIC OUTLOOK) FOR DETAILS. PTYPE BECOMES A CONCERN ACROSS NW INDIANA AND SW LOWER MICHIGAN SATURDAY NIGHT...MAINLY AFTER MIDNIGHT...AS COLD AIR UNDERCUTS THE LINGERING MELTING LAYER AND DYNAMIC COOLING COMMENCES. LATEST SREF PROBABILITIES, ALONG WITH GFS/ECMWF ITERATIONS, SUGGEST THAT BETTER CHANCES FOR MEASURABLE SNOW/SLEET WILL BE JUST WEST OF OUR AREA. SFC TEMPS MAY COOL TO NEAR FREEZING AFTER 08/09Z IN OUR NW WHICH COULD ALLOW FOR A BRIEF PERIOD OF FREEZING RAIN. EXPECT ANY FZRA TO BE TRANSIENT WITH QUICK CHANGEOVER TO LIGHT SNOW/SLEET/DRIZZLE LIMITING/INHIBITING ICE ACCRETIONS. OTHERWISE...OPTED TO HOLD WITH SNOW/SLEET ACCUMS OF A TRACE TO 0.5" IN OUR FAR NORTHWESTERN ZONES...MAINLY RAIN ELSEWHERE THROUGH DAYBREAK SUNDAY. LONG TERM.../SATURDAY THROUGH THURSDAY/ MAIN CONCERN FOR LONG TERM PERIOD IS PRECIP TYPE ON SUNDAY AS STORM SYSTEM DEPARTS. NEXT WEEK WILL FEATURE COLDER AIR AND A FEW ALBERTA CLIPPER SYSTEMS MOVING BY TO OUR NORTH. A POTPOURRI OF PRECIPITATION TYPES POSSIBLE ACROSS THE AREA ON SUNDAY DEPENDING ON WHICH MODEL IS FAVORED. ECMWF THERMAL PROFILE INDICATES FREEZING RAIN POTENTIAL ON SUNDAY MORNING FROM HIGHWAY 15 WEST WHILE GFS WOULD INDICATE NO FREEZING RAIN POSSIBILITY AND A TRANSITION FROM RAIN TO MOSTLY SNOW WITH SOME SLEET BY MID DAY. WITH TRANSITION ZONE DIRECTLY OVER THE FORECAST AREA...AND MODEL UNCERTAINTY...HAVE KEPT MOST ALL PRECIP TYPES IN THE FORECAST AND WILL ATTEMPT TO NARROW THE POSSIBILITIES IN FUTURE FORECAST ISSUANCES. AFTER THIS SYSTEM MOVES AWAY...A COLDER AIRMASS WILL MOVE IN. IF WE CLEAR OUT ON MONDAY NIGHT...TEMPERATURES COULD GET QUITE COLD WITH A HIGH PRESSURE CENTER OVER EASTERN ILLINOIS KEEPING WINDS LIGHT TO CALM. A FEW CLIPPER TYPE SYSTEMS WILL MOVE BY TO OUR NORTH NEXT WEEK. CONTINUED NORTHERLY FLOW BEHIND THESE SYSTEMS WILL ALLOW ARCTIC CANADIAN AIR TO INFILTRATE MOST OF THE MIDWEST/UPPER GREAT LAKES BY THE END OF THE WEEK. LONG TERM PATTERN LOOKS TO REMAIN COOLER THAN NORMAL AS EASTERN CANADA TROUGH KEEPS OUR AREA IN NORTHERLY FLOW. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST SATURDAY FOR LMZ043-046. && $$ SHORT TERM...STEINWEDEL LONG TERM...BENTLEY AVIATION...MURPHY UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
303 PM CST SAT JAN 12 2013 .SYNOPSIS... COLD FRONT PUSHING INTO THE OHIO VALLEY THIS AFTERNOON...WITH COLD AIR OOZING INTO THE UPPER MISSISSIPPI VALLEY BEHIND IT. LONG WAVE TROUGH SPANNING THE ROCKIES...WITH ENERGY LIFTING OUT OVER THE CENTRAL US IN FAST SOUTHWEST FLOW. LEAD SHORTWAVE GENERATING SOME SNOW/SLEET OVER NORTHERN MO AND INTO SE IA AT THIS TIME. MAIN PRECIP AREA ACROSS SOUTHERN MO AND SOUTHERN ILLINOIS IS ALSO EXPANDING NORTHWARD AND IS NOW PUSHING INTO CENTRAL ILLINOIS AHEAD OF THE MAIN SHORT WAVE...WHICH CAN BE SEEN ON SATELLITE LIFTING OUT OF ARKANSAS. && .SHORT TERM...TONIGHT AND SUNDAY... MAIN FORECAST QUESTIONS THIS AFTERNOON CENTER AROUND DEVELOPING PRECIPITATION EVENT FOR TONIGHT. THE INITIAL WAVE OF LIGHT SNOW/SLEET NOW MOVING ACROSS EASTERN IA WILL HELP COOL AND SATURATE THE COLUMN AHEAD OF TONIGHTS WAVE BUT WILL HAVE LITTLE OTHER IMPACT. FOR TONIGHT...OF THE SHORT RANGE MODELS...THE RAP IS THE MOST AGGRESSIVE WITH SNOWFALL AMOUNTS...SUGGESTING 4 TO 6 INCHES ALONG AND EAST OF THE MISSISSIPPI RIVER. MEANWHILE...THE NAM...GFS...AND ECMWF ARE MORE CONSERVATIVE WITH 2-3 INCHES AT MOST. THUS WILL FAVOR A BLEND OF THE NAM AND ECMWF FOR THIS FORECAST...ESPECIALLY FOR MOISTURE PARAMETERS. THERE IS CONSISTENCY IN THE FORECAST SOUNDINGS...SHOWING A LARGE WEDGE OF WARM AIR ALOFT...ESPECIALLY EAST OF THE MISSISSIPPI RIVER...THAT WILL HAVE TO COOL BEFORE PRECIP CHANGES TO SNOW. CURRENT THINKING IS THAT NEAR THE RIVER THE PERIOD OF SLEET SHOULD BE BRIEF...BUT WILL LAST LONGER AS YOU GO EAST. BUREAU/PUTNAM COUNTIES COULD SEE A COUPLE OF HOURS OF SLEET BEFORE IT CHANGES TO SNOW BY MIDNIGHT. IT IS ALSO NOT OUT OF THE QUESTION FOR A BRIEF PERIOD OF FREEZING RAIN TO FALL AT ONSET IN THE BUREAU/PUTNAM COUNTY AREA. HOWEVER...IF THIS WOULD OCCUR...THE EVAPORATIVE COOLING WOULD QUICKLY CHANGE IT TO SLEET. AND WITH THE WARM TEMPERATURES THESE LAST FEW DAYS...ONLY ELEVATED SURFACES SHOULD BE AT RISK FOR FREEZING. IN TERMS OF SNOW AMOUNTS...THE GARCIA METHOD WOULD SUGGEST 2-4 INCHES IN THE HEAVIEST BAND FROM THE QUAD CITIES NORTHEASTWARD. THE MODEL TIME SECTIONS DO SUPPORT THIS...SHOWING POTENTIAL FOR DENDRITIC GROWTH IN THAT SAME AREA. WHILE DENDRITES WOULD INCREASE AMOUNTS...THE SHORT DURATION OF THE EVENT AND ANY SLEET AT ONSET WILL LIMIT THE ACCUMULATIONS. THE BOTTOM LINE IS THAT I EXPECT A SHARP CUT-OFF IN SNOW ACCUMULATIONS SOMEWHERE IN THE VICINITY OF THE 380 CORRIDOR...THE HEAVIEST SNOW AMOUNTS IN THE 2-4 INCH RANGE FROM NEAR THE QUAD CITIES NORTHEASTWARD TO FREEPORT...AND A LONGER PERIOD OF SLEET WITH LESSER SNOW ACCUMULATIONS AS YOU MOVE TOWARD THE PRINCETON ILLINOIS AREA. THE MAIN PRECIP EVENT WILL BEGIN AFTER 6 PM TONIGHT...CHANGING TO SNOW AREA WIDE BY MIDNIGHT AND SHOULD HAVE EXITED ALL BUT THE EXTREME EASTERN PORTIONS OF THE CWFA BY 6 AM. DMD .LONG TERM...SUNDAY NIGHT THROUGH NEXT SATURDAY... SUNDAY NIGHT AND MONDAY...LATEST 12Z RUN MODELS IN GOOD AGREEMENT OF SUGGESTING SFC RIDGING SLIDING ACRS THE REGION FROM THE WEST SUNDAY NIGHT...WHILE CONFLUENT FLOW REGION WEST OF L/W TROF TRYING TO PHASE ACRS THE EASTERN ROCKIES. EXPECT CLEARING SKIES AS HIGH CLOUDS NORTHWEST OF LLVL BAROCLINIC REGION PUSH EASTWARD...COMBINED WITH DECREASING WINDS FOR A COLD NIGHT OVER FRESH SNOW COVER. SOME SINGLE DIGITS POSSIBLE BY EARLY MON MORNING. MAINLY CLEAR SKIES AND COLD CONDITIONS TO FINISH OUT THE PERIOD WITH HIGHS IN THE 20S MON AND SINGLE DIGITS TO LOWER TEENS MON NIGHT. SOME LIGHT RETURN FLOW MAY MAKE FOR NON-DIURNAL TEMP TRENDS PRE-DAWN EARLY TUE MORNING WEST OF THE MS RVR. TUESDAY AND WEDNESDAY...LATEST RUN MEDIUM RANGE SOLUTIONS SUGGEST THE ABOVE MENTIONED LONG WAVE TROF AXIS WILL SHEAR ACRS THE MID CONUS THIS PERIOD FROM THE GRT LKS...ALL THE WAY TO THE BAJA OF MEX. UPPER RIDGE ALONG AND JUST OFF THE WEST COAST AMPLIFIES...EVENTUALLY DUMPING RIDGE-RIDING WAVE ENERGY DOWN ACRS THE UPPER MIDWEST AND GRT LKS THROUGH MID WEEK. HOW FAR SOUTH THIS CLIPPER TYPE WAVE WILL EVENTUALLY DIG IS STILL SOMEWHAT UNCERTAIN...ALL LONGER RANGE MODEL SOLUTIONS BUT THE 12Z GFS KEEP LEAD WAVE AND IT/S ASSOCIATED PRECIP TO THE NORTH OF THE AREA UNTIL MAYBE WED NIGHT WHEN SOME FLURRIES MAKE IT ACRS THE NORTHEASTERN THIRD OF THE AREA/CWA UNDER RE- ENFORCING CYCLONIC FLOW DIGGING ACRS THE SOUTHWESTERN GRT LKS. THE 12Z GFS IS MORE PROGRESSIVE AND DEEPER SOUTH WITH THE CLIPPER AND PRODUCES LIGHT SNOW ACRS MOST OF THE LOCAL AREA TUE NIGHT INTO WED MORNING BEFORE SHUTTLING QUICKLY OFF TO THE EAST. FOR NOW WILL SIDE WITH THE MAJORITY AND KEEP THE FCST DRY...WITH THERMAL MODERATION FROM THE SOUTHWEST AHEAD OF THE NORTHERN STREAM CLIPPER. HIGHS TUE NEAR 30...MAY TRANSLATE INTO THE 30S BY WED BEFORE COLD FRONT OFF THE PASSING CLIPPER SYSTEM TO THE NORTH SWEEPS THROUGH THE CWA BY LATE WED. THURSDAY THROUGH SATURDAY...LATEST RUN MEDIUM RANGE MODEL SOLUTIONS AND ENSEMBLES GENERALLY SUGGEST WHILE A TYPE OF REX BLOCK SETS UP ACRS THE WEST COAST AND SOUTHWESTERN U.S...BROAD UPPER LEVEL TROFFINESS SETS UP ACRS MUCH OF THE EASTERN CONUS SOUTH OF NORTHERN HUDSON BAY POLAR VORTEX. A RIBBON OF LLVL BAROCLINICITY SETS UP PARALLEL TO THIS FEATURE FROM SOUTH CENTRAL CANADA...TO THE MID ATLANTIC WHILE A BUILDING DOME OF VERY COLD AIRMASS LOOMS ACRS THE EASTERN TWO THIRDS OF CANADA. WHILE THE REAL COLD AIR REMAINS BOTTLED UP BY THIS PATTERN...WILL CONTINUE TO ADVERTISE MODERATING TEMPS THROUGH SAT. DRY CONDITIONS TOO AS ANY IMPULSES WILL LOOK TO RIPPLE ALONG THE BAROCLINIC RIBBON AND PRODUCE PRECIP MAINLY OT THE NORTH ACRS THE DAKOTAS...MN...WI AND THE NORTH HALF OF THE GRT LKS INTO SAT NIGHT. SOME LONGER RANGE SIGNS OF PLUNGING JET ENERGY TO ALLOW SOME OF THE ARCTIC AIR TO BREAK LOOSE AND SPILL ACRS THE WESTERN GRT LKS BY EARLY NEXT WEEK. ..12.. && .AVIATION... A WINTRY MIX WILL OVERSPREAD THE AREA THIS EVENING. SITES ALONG AND WEST OF THE MISSISSIPPI RIVER COULD SEE A BRIEF PERIOD OF SLEET AT ONSET WHICH WILL RAPIDLY CHANGE OVER TO SNOW. EAST OF THE MISSISSIPPI RIVER...ROUGHLY FROM PRINCETON IL TO MACOMB IL...PRECIPITATION IS EXPECTED TO BEGIN WITH A BRIEF PERIOD OF FREEZING RAIN EARLY THIS EVENING...CHANGING TO SLEET FOR SEVERAL HOURS...AND THEN FINALLY OVER TO SNOW AROUND MIDNIGHT. AREA WIDE... SNOWFALL RATES WILL BE MOST INTENSE BETWEEN 3Z AND 9Z OVERNIGHT... AND SNOW IS EXPECTED TO END BY 12Z. OTHERWISE... BY 02Z LOOK FOR PREDOMINANTLY MVFR CIGS AND VSBYS WITH LOCAL IFR IN HEAVIER PRECIPITATION. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR CLINTON-DES MOINES-JACKSON-LEE-LOUISA-MUSCATINE- SCOTT. IL...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR BUREAU-CARROLL-HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER-PUTNAM-ROCK ISLAND-STEPHENSON- WARREN-WHITESIDE. MO...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST SUNDAY FOR CLARK. && $$ DMD/12/DMD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1132 PM CST FRI JAN 11 2013 .AVIATION... VFR CONDITIONS WILL PREVAIL MOST TO ALL OF THE NEXT 24 HOURS AT ALL TERMINALS. KCID AND KDBQ TERMINALS...A 1 TO 3 HOUR PERIOD OF SCT- BKN LOW CLOUDS AT 1-2K AGL MAY FOLLOW COLD FRONTAL PASSAGE BETWEEN 12-15Z THIS MORNING. AFTER 21Z...BKN-OVC LOW/MID CLOUDS WITH POSSIBLY LIGHT SNOW MAY AFFECT KMLI AND KBRL TERMINALS WITH MVFR CONDITIONS POSSIBLE IN ANY SNOW THROUGH 13/06Z. NICHOLS && .PREV DISCUSSION... /ISSUED 302 PM CST FRI JAN 11 2013/ SYNOPSIS... 12Z UA ANALYSIS HAS A STRONG SYSTEM OVER THE ROCKIES WITH STRONG SOUTHWEST FLOW FROM NORTHERN MEXICO INTO THE GREAT LAKES. SATELLITE TRENDS THROUGH MID AFTERNOON INDICATE THE LOW CLOUDS ARE BREAKING UP AS DEEPER MIXING OCCURS BUT MID AND HIGH LEVEL CLOUDS ARE STREAMING IN OVER THE REMAINING LOW CLOUDS. 18Z SFC ANALYSIS HAS A LOW NORTH OF KATY WITH ANOTHER NORTHEAST OF KLIC. A STRONG COLD FRONT CONNECTED BOTH LOWS AND THERE WERE NUMEROUS TROFS FROM THE GREAT LAKES BACK INTO THE SOUTHERN PLAINS. DEW POINTS WERE IN THE TEENS AND 20S ACROSS THE NORTHERN PLAINS WITH 30S AND 40S ACROSS MUCH OF THE GREAT LAKES AND MIDWEST. DEW POINTS IN THE 50S AND 60S RAN FROM THE OHIO VALLEY INTO THE DEEP SOUTH. SHORT TERM...LATE THIS AFTERNOON THROUGH SATURDAY WE ARE DEALING WITH ADVECTION FOG. IN ADVECTION FOG YOU CAN HAVE EXTREMELY DENSE FOG EVEN THOUGH WINDS ARE 10 TO 20 MPH. ALBEIT FAR FROM PERFECT...THE RAP MODEL TRENDS STRONGLY POINT TO DENSE FOG CONTINUING INTO THE EVENING ACROSS THE NORTHERN CWFA. AS FOR HEADLINES...THE DENSE FOG ADVISORY WILL BE EXTENDED UNTIL MIDNIGHT FROM DUBUQUE ON WEST IN THE HWY 20 CORRIDOR. PER OBSERVATIONS AND WHAT WEB CAMS ARE AVAILABLE...THE NORTHERN PARTS OF LINN/JONES/JACKSON COUNTIES IN IOWA AND STEPHENSON COUNTY IN ILLINOIS STILL HAVE DENSE FOG OVER THEM. THUS THESE COUNTIES AND JO DAVIESS COUNTY WILL HAVE THE DENSE FOG ADVISORY EXTENDED THROUGH 6 PM. THE POSSIBILITY DOES EXIST THAT THE HEADLINES MAY BE DROPPED EARLY. THAT WILL DEPEND UPON STRONGER WINDS PROMOTING MIXING OF THE BOUNDARY LAYER TO CAUSE THE FOG TO LIFT. AFTER MIDNIGHT...A STRONG COLD FRONT WILL SWEEP THROUGH THE CWFA. THIS FRONT WILL SCOUR OUT WHAT REMAINING FOG IS ACROSS THE AREA. VERY BRISK CONDITIONS WILL BE SEEN ACROSS THE AREA ON SATURDAY BEHIND THE FRONT. THE STRENGTH OF THE CAA ON SATURDAY WOULD NORMALLY RESULT IN UNSTABLE CONDITIONS WITH CONVECTIVE SHOWERS DEVELOPING. HOWEVER... LOW LEVEL LAPSE RATES REMAIN QUITE STABLE DURING THE DAY AND FCST SOUNDINGS SHOW A VERY PRONOUNCED INVERSION ACROSS THE AREA. THUS SATURDAY WILL REMAIN DRY. LOW TEMPERATURES TONIGHT WILL OCCUR AROUND 8 AM SATURDAY. THE HIGH TEMPERATURES FOR THE DAYLIGHT HOURS ON SATURDAY WILL OCCUR BETWEEN 8 AND 10 AM FOLLOWED BY SLOWLY FALLING TEMPERATURES. TEMPERATURES MAY REBOUND A LITTLE DURING THE AFTERNOON BUT WILL BE BELOW THE MORNING HIGHS. ..08.. LONG TERM...SATURDAY NIGHT THROUGH FRIDAY SATURDAY NIGHT AND SUNDAY TO BE THE TRICKY PERIOD. LAST NIGHT THE ECMWF TOOK A JOG TO THE NORTHWEST WITH A SHORTWAVE AND SURFACE LOW THAT MOVES FROM EAST TEXAS NORTHEAST UP THE OHIO VALLEY. IT APPEARS TO BE BRINGING THE WHOLE FEATURE FARTHER NORTHWEST...AS WELL AS TAKING ADVANTAGE OF SOME DEEPER FRONTOGENESIS THAT SEEMS TO BE FORMING ON THE NORTH SIDE OF THE FEATURE. THIS MORNING...MORE OF THE MODELS FOLLOWED THAT TREND...AND ARE NOW BRINGING A NICE SWATH OF SNOW TO THE FORECAST AREA. AREAS SOUTHEAST OF A LINE FROM CEDAR RAPIDS TO DUBUQUE ARE NOW LOOKING AT A NICE 1 TO POSSIBLY 3 INCH SNOWFALL EVENT...ASSUMING WE CAN GET ENOUGH MOISTURE INTO THE AREA AND THE ECMWF AND GFS ISENTROPIC AND FRONTOGENESIS LIFT PROGS ARE CORRECT. HAVE RAISED POPS...BUT IF THIS TREND CONTINUES WITH TONIGHTS MODEL RUNS...WE COULD RAISE POPS AGAIN. SUNDAY NIGHT AND MONDAY TO BE COLD...ESPECIALLY IF WE CAN GET SOME SNOW ON THE GROUND TO ENHANCE THE STRONG SURFACE RIDGE THAT WILL BE SITTING OVER THE AREA BY EARLY MONDAY MORNING. AT THIS TIME IT LOOKS LIKE WE MAY SEE SOME SINGLE DIGITS IN THE NORTHWEST PORTIONS OF THE FORECAST AREA. IF WE DO GET THE NEW SNOWPACK...NEARLY THE WHOLE CWA COULD HAVE SINGLE DIGIT MINS WITH NEAR ZERO VALUES POSSIBLE NORTHWEST. HIGHS ON MONDAY TO STILL BE CHILLY WITH THE RIDGE STILL OVERHEAD...AND CURRENTLY HAVE MID TO UPPER 20S. TUESDAY THE MAIN UPPER LEVEL TROUGH TO SLOWLY MOVE OVERHEAD...INCREASING CLOUD COVER SOMEWHAT AND WITH SOME WEAK WARM AIR ADVECTION BEGINNING ALOFT SOME MODERATION OF TEMPERATURES IS POSSIBLE. WEDNESDAY A STRONG CLIPPER IS LIKELY TO MOVE OUT OF CANADA IN THE LONGWAVE TROUGH. THIS SYSTEM TO STAY MOSTLY NORTH OF THE AREA...BUT IT WILL PULL SOME WARMER TEMPERATURES ALOFT OVER THE AREA...FOR A CONTINUATION OF THE WARMING TREND STARTED ON TUESDAY. HIGHS WEDNESDAY AFTERNOON SHOULD BE IN THE 30S NEARLY EVERYWHERE. WITH THE CLIPPER NOW HAVING MOVED OFF TO THE EAST BY WEDNESDAY NIGHT...A FRESH SHOT OF COLDER AIR WILL MOVE INTO THE CWA FROM THE NORTH AS THE UPPER LEVEL TROUGH AXIS SHARPENS. IT LOOKS LIKE A SHORTWAVE MAY DIVE THROUGH THE AREA THURSDAY...BUT SOME MODELS KEEP IT TOO FAR NORTH TO AFFECT THE AREA...SO HAVE LEFT FORECAST DRY FOR NOW. FRIDAY LOOKS COLD AND DRY AS WELL. LE && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ NICHOLS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
245 PM EST SAT JAN 12 2013 .SYNOPSIS... CROSSING LOW PRESSURE WILL SPREAD RAIN OVER THE UPPER OHIO VALLEY REGION ON SUNDAY...AND WILL PULL A COLD FRONT THROUGH BY MONDAY. && .NEAR TERM /THROUGH SUNDAY/... SHRA AREA WITH SHRTWV IN SWLY FLOW ALOFT WAS MOVG ACRS KY THIS AFTN...AND THAT CLUSTER IS EXPECTED TO DVLP UP THE OH RIVER AND SHOULD AFFECT THE AREA LTR THIS EVE. EVE PRECIP PROBABILITIES HAVE BEEN ADJUSTED FOR THIS POTENTIAL USING RAP HRLY OUTPUT...AND BASICALLY FOCUS THE BTR SHRA CHCS OVR AREAS WEST OF PITTSBURGH BEFORE THE DISTURBANCE LIFTS NWD LTR TNGT. OTHERWISE...VERY WARM TEMPERATURES CAN BE EXPECTED THROUGH SUNDAY AS DETERMINISTIC MODELS HAVE CONTINUED THE TREND OF HOLDING FRONT TO THE WEST OF THE REGION THROUGH THE NEAR TERM. IN ADDITION...THE HEAVIER RAIN POTENTIAL WILL ALSO BE SHIFTED WEST WITH THE BOUNDARY...THUS LIMITING RAIN AMOUNTS FOR MOST COUNTIES AS WELL AS ALLOWING MORE RUNOFF TIME FOR THE LAST OF THE SNOW MELT. THE FORECAST THUS FEATURES REDUCED PRECIP PROBABILITIES FOR LATE TNGT AND EARLY SUNDAY...ALTHOUGH CHC NMBRS HAVE GENLY BEEN MAINTAINED UNTIL LOW PRES SWEEPS ACRS OHIO DURING THE AFTN. CATEGORICAL NMBRS HAVE BEEN RECONSTRUCTED FOR THAT EVENTUALITY WITH RAIN AMOUNTS APPROACHING AN INCH LIMITED TO AREAS ALONG AND NORTH OF A ZANESVILLE TO FRANKLIN LINE. GIVEN THIS SCENARIO...STREAM AND RIVER RISES CAN BE EXPECTED...BUT FLOODING IS NOT ANTICIPATED. THE WARM NEAR TERM TEMPS WERE FORECAST USING LAMP GUIDANCE AND PERSISTENCE FOR SUNDAY. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... A TAPERING OF POPS TO LIKELY NMBRS WAS COMPLETED FOR SUNDAY EVE...AND TO CHC NMBRS THEREAFTER AS THE AFOREMENTIONED LOW DRAGS THE COLD FRONT OVR THE UPR OH REGION WITH ITS EXIT. RESIDUAL RAIN SHOWERS MAY CHANGE TO SNOW BY MONDAY MRNG...BUT NO SIGNIFICANT ACCUMULATION IS FORTHCOMING. THE LATEST NAM AND GFS ARE IN AGREEMENT IN DEPICTIONS OF SUFFICIENT SWD PENETRATION OF THE FRONT FOR DRY WEATHER FOR MOST ZONES...AND A STEADY POP REDUCTION FOR SERN COUNTIES ON MONDAY. THOSE MDLS ALSO INDICATE DVLPMNT OF LOW PRES ALNG THE FRONT ON TUESDAY. THAT SYSTEMS PROGRESS ACRS THE VIRGINIAS MAY SPREAD PCPN OVR AREAS ARND AND SE OF MORGANTOWN...AND WARM ADVCTN ABOVE THE BNDRY LYR MAY BE SUFFICIENT FOR A PERIOD OF FREEZING RAIN WITH THE LIGHT SNOW FOR THE RIDGE ZONES. FOR NOW...LOW CHC POPS WL SUFFICE FOR THAT SITUATION AS THE BETTER POTENTIAL LKS TO BE FARTHER SOUTH AND EAST. SHORT TEMPS WERE FORECAST USING A BLEND OF GUIDANCE AND GENERALLY FEATURE A SLOWER COOLING TREND. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... SVRL WEAK AND FAST MOVG SYSTEMS ARE EXPD THRU THE PD. WITH TIMING DETAILS DIFFERING AMONG THE MODELS...PREFERRED AN ECMWF/HPC CHART BLEND TO SMOOTH OUT SOME OF THE DIFFERENCES. EXPCTG HIGH PRES TO BLD IN TUE NGT INTO WED. A COLD FRONT IS EXPD TO DROP SE ACRS THE GT LKS RGN WED NGT INTO THU WITH A CHC OF SHSN...BUT MOISTURE IS LMTD. A FEW SHSN MAY LINGER IN COLD WRLY FLOW THRU THU NGT BEFORE ANOTHER WK SYSTEM SKIRTS THE NRN PTN OF THE CWA FRI. YET ANOTHER WK COLD FRONT IS EXPD FOR SAT. MAY SEE JUST ENOUGH WARM AIR AHEAD OF IT FOR A MIX OF SHRA/SHSN...BUT AGAIN MOISTURE SHOULD BE LMTD. WENT NR OR A LTL BLW HPC TEMP GUIDANCE...RESULTING IN NR OR SLIGHTLY ABV NRML TEMPS THRU THE PD. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... LOW LVL MOISTURE WL CONT TO BRING OCNL MVFR CIGS TO MOST OF THE TAF SITES THROUGH THIS AFTN...EXCPT IFR FOR FKL AND DUJ. THINK THE LWR CIGS WL SCT OUT BY THIS EVE...THEN IFR REDVLPS FOR FKL AND DUJ OVRNGT. WITH MID LVL CLDS NOT CERTAIN REST OF THE TAF SITES WL SEE SGFNT RESTRICTIONS...BUT WL HAVE TO MONITOR FOR THIS THRU THE EVE. LLVL JET MOVG IN OVRNGT WL BRING A LLWS POTENTIAL AFTR 08-10Z MOST PLACES. SHOULD GET SOME LMTD MIXING AFT 15Z SUN SO ENDED LLWS EXCPT FOR FKL/DUJ WHERE LOW CLDS SHOULD LIMIT MXG. A COLD FRONT WL APRCH FM THE WEST SUN...AND MENTIONED SHRA AT ZZV BY LT MRNG...AND LT AFTN FOR PIT. .OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/... RESTRICTIONS ARE EXPD SUN NGT INTO MON AS THE COLD FRONT MOVES THRU THE AREA. RESTRICTIONS ARE PSBL AGAIN WED NGT AND THU AS ANOTHER COLD FRONT MOVES THRU. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 15/07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
722 PM EST SUN JAN 13 2013 .UPDATE... ISSUED AT 721 PM EST SUN JAN 13 2013 CALLS TO SPOTTERS IN ALGER/LUCE COUNTY AND A LOOK AT RADAR IMAGERY INDICATE ONLY -SHSN ARE ONGOING IN THAT AREA ATTM. DESPITE APRCH OF DISTURBANCE/AREA OF DEEPER MSTR...LLVL ACYC FLOW/LACK OF LLVL CNVGC APPEARS TO BE THE MAIN IMPEDIMENTS TO HEAVIER LES DEPSITE ONSHORE NW FLOW AND SUFFICIENTLY LO H85 TEMPS...-13C TO -15C PER RUC ANALYSIS. LATEST HI RES NUMERICAL MODELS INDICATE LLVL FLOW WL BECOME MORE CYC WITH FOCUSED LLVL CNVGC IN ERN ALGER/NRN LUCE COUNTIES FOLLOWING PASSAGE OF UPR DISTURBANCE OVERNGT AS EVEN COLDER AIR WITH H85 TEMPS FALLING TO -18C BY 12Z. THESE FACTORS SHOULD CONSPIRE TO INCRS INTENSITY OF THE SHSN IN THIS AREA AFT 06Z. SO ADJUSTED THE LES ADVY TIMING TO 06Z TO 18Z FOR ALGER/LUCE COUNTIES. BY 18Z MON...EXPECT THE LARGER SCALE FLOW TO BACK SUFFICIENTLY WSW TO END THE LES IN ALGER/LUCE COUNTIES. HEADLINES FOR ONTONAGON/HOUGHTON/KEWEENAW COUNTIES APPEAR ON TRACK AND VERIFIED BY RECENT SN REPORTS. SO MADE NO CHANGES TO THE ADVYS IN PLACE FOR THOSE ZONES. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 400 PM EST SUN JAN 13 2013 MOISTURE DECREASES AND THE INVERSION HEIGHT FALLS TO AROUND 900MB AT IWD AROUND OR SHORTLY AFTER 06Z...DECREASING THE POTENTIAL FOR ANY SIGNIFICANT ACCUMULATION BEYOND THAT POINT. MUCH OF BARAGA AND MARQUETTE COUNTIES WILL ALSO MISS OUT ON ACCUMULATIONS GREATER THAN AN IN INCH OR TWO NEAR THE SHORELINES. OTHERWISE AROUND THE S EDGE OF LAKE SUPERIOR...FAVORABLE NW FLOW OFF THE RELATIVELY WARM WATERS...PLENTY OF MOISTURE BELOW 850MB COINCIDING WITH THE DGZ...WILL CONTINUE TO BRING BANDS OF LAKE EFFECT SNOW SHOWERS FROM THE PORCUPINE MOUNTAINS...AND MAINLY EAST OF AU TRAIN THROUGH N LUCE COUNTY. WHILE ACCUMULATIONS WILL LIKELY BE LESS FOR THE 6HR PERIOD FORM 06Z-12Z FOR THE WESTERN ADVISORY...WITH ACCUMULATIONS OF 1-2IN...THE INTENSITY WILL LIKELY PICK UP AGAIN TOWARD DAYBREAK AT WINDS TURN MORE WESTERLY...BRINGING THE FOCUS UP TO THE TWIN LAKES-PAINESDALE-CMX AREA...AND THEN LIKELY FROM FREDA-CMX AND N BY LATE AFTERNOON. THE BEST SNOW MAY ALSO BE ONGOING TOWARD THE END OF THE EASTERN ADVISORY /MONDAY MORNING/...GIVEN THE WIND DIRECTION AND 850MB TEMPS FALLING FROM AROUND -12C THIS AFTERNOON TO AROUND -16C. VERY LITTLE CHANGE WILL BE NOTED OVER THE W...WITH ONLY ABOUT A 2C DROP IN 850MB TEMPS. WENT A LITTLE MORE OPTIMISTIC WITH THE CLEARING/DIMINISHING CLOUD COVER TONIGHT AND MONDAY OVER CENTRAL UPPER MI...AS HIGH PRESSURE ACROSS THE N AND CENTRAL PLAINS SLOWLY WEAKENS THE LINGERING TROUGH OVERHEAD. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 400 PM EST SUN JAN 13 2013 LAKE EFFECT SNOW WILL DOMINATE THE FORECAST FOR MOST OF THE LONG TERM. IN FACT...AREAS FAVORED IN WESTERLY AND NORTHWESTERLY FLOW WILL LIKELY SEE SNOW EACH DAY IN SOME FORM OR ANOTHER THROUGH NEXT WEEKEND. AWAY FROM THESE AREAS...IT WILL END UP BEING FAIRLY DRY...ALTHOUGH THERE WILL BE SOME OPPORTUNITIES FOR SNOW WITH CLIPPER SYSTEMS. LAKE EFFECT SNOW WILL BE ONGOING MONDAY NIGHT IN THE WESTERLY PBL FLOW. IN FACT...THE NAM AND LOCAL HIGH RES MODELS SUGGEST A SINGLE DOMINATE BAND CONTINUING FROM MONDAY AFTERNOON AND PERHAPS INTENSIFYING SOME AS A WEAK UPPER DISTRUBANCE MOVES OVERHEAD WITH A LITTLE ADDITIONAL MOISTURE. STILL LOOKS LIKE A DOMINATE BAND OF SNOW WILL PERSIST ACROSS THE KEWEENAW MONDAY NIGHT...THEN GRADUALLY SHIFT NORTH ON TUESDAY AS WINDS BACK AHEAD OF THE NEXT CLIPPER SYSTEM. TRICKY SNOWFALL FORECAST FOR THE KEWEENAW MONDAY NIGHT...AS THE EQL HEIGHT WILL RAISE TO NEARLY 9000 FT AND NEARLY ALL OF THE BEST OMEGA LIES IN THE DGZ. IN FACT...THE COBB METHOD WOULD SUGGEST SNOW RATIOS OF 25-30:1 MONDAY NIGHT. THIS COMBINED WITH QPF VALUES OF AROUND 0.15 INCH MON NIGHT WOULD SUGGEST THAT LES ADVISORY FOR THE KEWEEWAW WILL NEED TO BE EXTENDED THROUGH MON NIGHT. WILL NEED TO WATCH FOR HIGHER AMOUNTS OF SNOW ON MONDAY NIGHT...BUT EXTENDING THE ADVISORY SEEMS TO BE THE BEST COURSE OF ACTION FOR NOW. TUESDAY WILL GENERALLY BE QUIET AHEAD OF A CLIPPER SYSTEM. WEAK WARM ADVECTION SHOULD ALLOW TEMPS TO RISE INTO THE UPPER TEENS AND LOWER 20S. THE CLIPPER SYSTEM MOVES THROUGH TUESDAY NIGHT INTO WED MORNING. BEST DYNAMICS ACROSS LAKE SUPERIOR AND HAVE SUCH HAVE PLACED THE HIGHEST POPS ACROSS THE LAKE AND OVER THE EASTERN PART OF THE FORECAST AREA WHERE THERE MAY BE SOME WEAK LAKE MICHIGAN ENHANCEMENT. WILL KEEP CHANCE POPS ACROSS THE NORTH CENTRAL DUE TO DOWNSLOPING S-SW WINDS. IN FACT...THESE WINDS WILL BE RATHER GUSTY INTO WED MORNING. THE COLD FRONT/TROUGH ENDS UP SLOWING DOWN AS IT CROSSES THE REGION WED. THIS WILL MAKE IT JUST MARGINALLY COLD FOR LES IN THE NW FAVORED SNOWBELTS UNTIL LATER WED AFTN INTO WED NIGHT WHEN THE COLD AIR SURGES SOUTHWARD ONCE AGAIN. 850MB TEMPS WED NIGHT DROP TO -24C ACROSS THE LAKE SO THERE IS NO REASON WHY LES WILL NOT CONTINUE. ALTHOUGH THE MODELS DIFFER ON THE SPECIFICS IN DAYS 4-7 (THURSDAY-SUNDAY)...ALL SIGNS CONTINUE TO POINT TOWARD SOME OF THE COLDEST AIR OF THE YEAR THUS FAR MOVING ACROSS THE GREAT LAKES AS THE ARCTIC VORTEX MOVES TO SOUTHERN HUDSON BAY BY THE END OF THE WEEK. WITH THE AREA BEING UNDER NW FLOW...CLIPPER SYSTEMS ALONG WITH LES WILL BE THE MAIN DRIVERS FOR PRECIPITATION. AS USUAL...THE TIMING OF THESE SYSTEMS WILL BE DIFFICULT...BUT THE EMPHASIS IN THE EXTENDED WILL BE MUCH COLDER WITH CHANCES FOR SNOW EACH DAY. AS FOR A LITTLE MORE SPECIFICS...THURSDAY LOOKS TO BE COLD DAY WITH 850MB TEMPS DROPPING TO AROUND -25C BEHIND THE CLIPPER SYSTEM. THE GFS AND ECMWF BOTH IMPLY AN INVERTED TROUGH HANGING OVER THE LAKE ESPECIALLY ACROSS THE EAST AS THE SURFACE RIDGE MAINLY SLIDES SW OF THE FORECAST AREA. THIS WILL LIKELY ALLOW FOR LAKE EFFECT SNOW TO PERSIST IN THE W-NW FLOW FAVORED SNOW BELTS SUCH AS THE AREA FROM ONTONAGON TO THE KEWEENAW...AS WELL AS PLACES WELL EAST OF MUNISING. ALTHOUGH THERE WILL BE EXTREME INSTABILITY OFF THE LAKE WITH LAKE INDUCED DELTA-T VALUES OF 25-30C...EXPERIENCE SUGGESTS THAT SNOW RATIOS TEND TO BE QUITE LOW (GENERALLY 15-20:1) WITH ARCTIC TYPE LES DUE TO THE BEST DGZ BEING NEAR THE GROUND. DUE TO THIS AND THE DECREASING INVERSION AND BACKING WINDS INTO FRIDAY...IT IS UNCLEAR HOW HEAVY THE SNOW WILL ACTUALLY FALL...ALTHOUGH SNOW WILL BE RATHER PERSISTENT. FOR NOW...WILL CONTINUE WITH LIKELY POPS IN THE NW FAVORED SNOW BELTS SIMILAR TO PREVIOUS FORECASTS. DIFFERENCES OCCUR BETWEEN THE GFS AND ECMWF FOR THE WEEKEND. THE ECMWF IS MUCH MORE AGRESSIVE WITH THE WEEKEND SYSTEM...WITH THIS SYSTEM OPENING THE DOOR FOR THE ARCTIC VORTEX PLUNGING ACROSS THE UPPER GREAT LAKES BY SUNDAY NIGHT. THE GFS IS SLOWER...WAITING UNTIL SUN NIGHT CLIPPER FOR THE ARCTIC VORTEX TO SHIFT SOUTH. REGARDLESS OF WHAT HAPPENS...ALL SIGNS ARE POINTING TOWARD A VERY COLD PERIOD STARTING EITHER NEXT SUNDAY OR NEXT MONDAY. THE ECMWF CONTINUES TO SHOW 850MB TEMPS OVER LAKE SUPERIOR OF -35C BY NEXT MONDAY AND ALTHOUGH THE GFS IS WARMER...THE BROAD LONG WAVE PATTERN IS SIMILAR. WILL NOT GET TOO SPECIFIC FOR THE WEEKEND AND HOLD ONTO A CHANCE OF SNOW EACH DAY. THERE WILL LIKELY BE A PERIOD OF MORE WIDESPREAD SNOW AS THE CLIPPER MOVES THROUGH...BUT THAT IS BEYOND THE PREDICTABILITY OF THE NWP RIGHT NOW. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 624 PM EST SUN JAN 13 2013 CMX...EXPECT PREDOMINANT IFR CONDITIONS THIS PERIOD WITH PERSISTENT/ UPSLOPE WNW FLOW AND SUFFICIENT INSTABILITY FOR LES. THE BEST CHC FOR LIFR WX WL BE THIS EVNG AS DISTURBANCE/AREA OF DEEPER MSTR IMPACT THE AREA AND AGAIN ON MON MRNG WITH RETURN OF AREA OF SHARPER LLVL CNVGC ASSOCIATED WITH SLOWLY BACKING LARGER SCALE FLOW. IWD...WITH ARRIVAL OF DISTURBANCE/DEEPER MSTR THIS EVNG...EXPECT VFR WX EARLY TO DETERIORATE TO MVFR/OCNL IFR CONDITIONS. ONCE THIS DISTURBANCE PASSES AND THE FLOW BACKS MORE TO THE WSW LATER TNGT... THE MORE SGNFT SHSN WL DIMINISH. VFR CONDITIONS WL RETURN ON MON AS THE BACKING LLVL FLOW ADVECTS DRIER AIR OVHD. SAW...ALTHOUGH MVFR CONDITIONS MAY OCCUR THIS EVNG ASSOCIATED WITH THE PASSAGE OF AN UPR DISTURBANCE/DEEPER MSTR...EXPECT PREDOMINANT VFR WX THIS FCST PERIOD WITH DOWNSLOPE WNW FLOW VEERING WSW ADVECTING DRIER AIR INTO THE AREA IN THE WAKE OF DEPARTING DISTURBANCE. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 400 PM EST SUN JAN 13 2013 THE TROUGH LINGERING ACROSS LS WILL SLOWLY WEAKEN AS HIGH PRESSURE SINKS FROM CENTRAL CANADA INTO THE MID MISSISSIPPI VALLEY. EXPECT THE HIGH TO SLOWLY EXIT S TUESDAY IN RESPONSE TO A STRONGER LOW OVER SASKATCHEWAN SWINGING ACROSS ONTARIO TUESDAY NIGHT...AND INTO QUEBEC ON WEDNESDAY. SW GALES TO 35KTS WILL BE POSSIBLE TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. EXPECT THE EXTENDING TROUGH TO PUSH ACROSS LS ON WEDNESDAY...WITH A NW GALES TO 35KTS POSSIBLE BEHIND THE TROUGH...MAINLY WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT. A GALE WATCHED HAS BEEN POSTED FOR PORTIONS OF LAKE SUPERIOR. WINDS WILL SLOWLY DIMINISH AS THE TROUGH WEAKENS THURSDAY THROUGH FRIDAY IN RESPONSE TO LARGE HIGH PRESSURE ONCE AGAIN NEARING FROM CENTRAL CANADA AND THE PLAINS STATES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR MIZ002. LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 1 PM EST MONDAY FOR MIZ006-007. LAKE SUPERIOR... GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR LSZ265>267. GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ UPDATE...KC SHORT TERM...KF LONG TERM...MRD AVIATION...KC MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1246 PM EST SAT JAN 12 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 534 AM EST SAT JAN 12 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM NW ONTARIO INTO THE SW CONUS AND A RIDGE OVER THE EAST RESULTING IN SW FLOW FROM THE SRN PLAINS INTO THE WRN GREAT LAKES. A SHEARED SHORTWAVE TROUGH WAS LIFTING NORTHEAST THROUGH NRN MN. AT THE SFC...A 993 MB LOW WAS LOCATED OVER THE MN ARROWHEAD WITH A COLD FRONT EXTENDING TO THE SSE THROUGH NW INTO CNTRL WI. VERY MILD SSW FLOW AHEAD OF THE FRONT HAS PUSHED TEMPS INTO THE LOWER 40S ACROSS MOST OF UPPER MI. GUSTY SW WINDS HAVE DEVELOPED BEHIND THE COLD FRONT AS A 5MB/3HR PRES RISE MAX TRAILS THE FRONT OVER SRN MN. RADARS INDICATED AREAS OF LIGHT PCPN OVER ERN MN INTO NW WI WITH NO RETURNS TO THE EAST. MAIN FCST CONCERNS ARE WINDS AND LAKE EFFECT SNOW POTENTIAL. TODAY...MODELS HAVE BEEN CONSISTENT WITH THE LOW QUICKLY LIFTING NORTHEAST TO JAMES BAY BY LATE TODAY. THIS WILL DRAG THE COLD FRONT THROUGH THE CWA BY 18Z BRINGING THE STRONGEST ISALLOBARIC GRADIENT THROUGH THE WEST HALF OF UPPER MICHIGAN THIS MORNING. WITH STRONG CAA AND INCREASE IN MIXED LAYER DEPTH...GUSTY WINDS IN THE 25 TO 35 MPH RANGE ARE EXPECTED OVER MOST OF THE REGION. SINCE THE SW WINDS ARE MAINLY PARALLEL TO THE KEWEENAW PENINSULA THE STRONGER GUSTS ARE EXPECTED DURING THE AFTERNOON AS WINDS VEER MORE TO THE WSW. THIS WOULD BRING THE STRONGEST GUSTS MAINLY ACROSS THE WESTERN SHORE OF THE KEWEENAW. A WIND ADVISORY IS IN EFFECT WHICH HIGHLIGHTS THESE LOCATIONS. BY THE TIME THAT WINDS VEER TO THE WEST WHICH WOULD FAVOR LOCATIONS IN THE HIGHER TERRAIN AROUND CMX...THE GRADIENT WEAKENS. LAKE INDUCED CAPE VALUES CLIMB QUICKLY TO AROUND 300-400 J/KG BY LATE AFTERNOON AS 850 MB TEMPS FALL TO NEAR -15C. THE STRONGEST LOW LEVEL CONVERGENCE AND GREATEST LES IS EXPECTED TO FOCUS TOWARD THE NRN PORTION OF THE KEWEENAW....FROM CMX NORTHWARD. TONIGHT...INSTABILITY OVER THE LAKE WILL INCREASE AS 850 MB TEMPS DROP TO AROUND -18C. THE HIGHER RES MODELS SUGGEST THAT EVEN AS THE WINDS OVER WRN LAKE SUPERIOR VEER MORE TO THE NW...LAKE INDUCED TROUGHING WILL KEEP THE CONVERGENT WINDS OVER THE KEWEENAW. EVEN THOUGH INVERSION HEIGHTS ARE ONLY FCST NEAR 4K FT...WITH THE MOISTURE DEPTH TO AT LEAST 7K FT...AT LEAST MODERATE INTENSITY LES IS EXPECTED THAT COULD BRING 2 TO 4 INCHES TO LOCATIONS FROM NE ONTONAGON COUNTY THROUGH THE HIGHER TERRAIN OF THE KEWEENAW PENINSULA. A LES ADVISORY WAS POSTED WHICH EXTENDS THROUGH SUNDAY NIGHT(DETAILS IN SUBSEQUENT DISCUSSION). A SHORTWAVE MOVING TOWARD THE GREAT LAKE FROM THE CNTRL PLAINS ALONG WITH UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 170 KT 300 MB JET INTO NRN ONTARIO WILL ALSO SUPPORT AN AREA OF LIGHT SNOW THAT WILL GRAZE THE SE PORTIONS OF THE CWA. SINCE THE HEAVIER PCPN IS EXPECTED TO THE SOUTH...ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW AN INCH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 534 AM EST SAT JAN 12 2013 AREA WILL BE ENTERING BACK INTO A MORE WINTER TIME PATTERN TODAY...WHICH WILL CONTINUE THROUGH THE LONG TERM PERIOD. SYSTEM MOVING THROUGH THE LOWER GREAT LAKES TONIGHT INTO SUNDAY HAS HAS SHIFTED A LITTLE MORE TO THE NORTHWEST OVER THE LAST FEW RUNS AND NOW BRUSHES THE COUNTIES NEAR LAKE MICHIGAN WITH SOME LIGHT SNOW SUNDAY MORNING. THIS NORTHWEST SHIFT HAS CAUSES THE DEEPER MOISTURE WITH A LEFT OVER SHORTWAVE FROM THE LOW CURRENTLY IN MN TO REMAIN JUST TO THE WEST OF LAKE SUPERIOR ON SUNDAY MORNING AND THE FIRST PART OF THE AFTERNOON. THIS LEADS TO SOME CONCERN FOR THE INITIAL LAKE EFFECT FROM LINGERING SURFACE TROUGH OVER SOUTHERN LAKE SUPERIOR. SINCE THE COLD AIR SURGE EXPECTED TODAY INTO TONIGHT WILL BE FAIRLY SHALLOW...IT WILL SETUP A VERY STRONG INVERSION TONIGHT AROUND H800 OR 5KFT. THUS...DO EXPECT LAKE EFFECT TO BE OCCURRING OVER THE WEST-NORTHWEST FAVORED LOCATIONS IN THE WESTERN U.P. BUT HAVE SOME CONCERNS ON STRENGTH TO START THE PERIOD. ON THE POSITIVE SIDE...THE BEST FORCING WILL BE FOCUSED IN THE DGZ...BUT THERE IS SOME SHEAR IN THE CLOUD LAYER...SFC-H925 WINDS OUT OF THE NORTHWEST AND H850 WINDS OUT OF THE WEST IN THE MORNING AND THEN SOUTHWEST IN THE AFTERNOON. WONDERING IF THIS WILL KEEP THE FOCUS AWAY FROM A DOMINATE BAND IN MORE GENERAL MULTIBAND LAKE EFFECT. LAKE EFFECT SNOW PARAMETER...WHICH HAS DONE A GOOD JOB HIGHLIGHTING THE FEW LAKE EFFECT EVENTS WE HAVE HAD THIS SEASON...KEEPS VALUES LIMITED DURING THE MORNING HOURS AND WILL KEEP SNOWFALL AMOUNTS LIGHTER. ONCE THE SURFACE LOW SLIDES NORTHEAST INTO WESTERN QUEBEC SUNDAY AFTERNOON AND EVENING...THEN THE SURFACE TROUGH WILL SLIDE SOUTH SLIGHTLY LEADING TO LESS SHEAR AND RISING INVERSION HEIGHTS TO 6-7KFT DUE TO DEEPER MOISTURE IN MN BEING DRAGGED THROUGH THE WESTERN CWA. LAKE EFFECT SNOW PARAMETER PEAKS TO 2 IN THIS PERIOD...SO EXPECT INTENSITY OF THE LAKE EFFECT TO FOLLOW SUIT. AT THIS POINT...THINK IT WILL BE IN NORTHWEST FAVORED LOCATIONS ALTHOUGH HIGHER RESOLUTION MODELS ARE TRYING TO HINT AT ENHANCED CONVERGENCE IN THE HOUGHTON/ONTONAGON/GOGEBIC COUNTY AREA. CHECKLIST GIVES 3-5IN PER 12HRS FOR SUNDAY AND SUNDAY NIGHT AND THAT SEEMS TO FIT WELL WITH THE GOING FORECAST...AS SNOW RATIOS WILL BE IN THE 20-30 TO 1 RANGE. WITH TOTAL SNOW FROM TONIGHT THROUGH SUNDAY NIGHT OF 7 TO LOCALLY 14 INCHES...WILL ISSUE AN ADVISORY FOR KEWEENAW THROUGH ONTONAGON COUNTIES. WILL NEED TO WATCH GOGEBIC COUNTY NEAR THE PORCUPINE MOUNTAINS...AS ARE HINTS OF ENHANCED CONVERGENCE FOR HIGHER SNOWFALL AMOUNTS THERE. FARTHER EAST...WITH THE LIGHT SYNOPTIC SNOW LEAVING EARLY SUNDAY AFTERNOON...TRANSITION WILL OCCUR TO LAKE EFFECT IN THE NORTHWEST WIND BELTS IN THE AFTERNOON...AS THE SURFACE TROUGH SHIFTS WINDS. THERE TOO...AMOUNTS WILL BE LIGHT TO MODERATE ON SUNDAY AFTERNOON INTO THE EVENING...BUT COULD PEAK UP SOME AFTER MIDNIGHT WHEN THE INVERSION HEIGHTS RISE. MAY NEED AN ADVISORY ON FUTURE SHIFTS FOR THE SUN AFTERNOON/NIGHT PERIOD. SURFACE TROUGH THEN SHIFTS NORTH ON MONDAY...PUSHING THE SNOW OFFSHORE OVER THE EAST AND FOCUSES IT OVER THE KEWEENAW IN THE WEST. INTENSITY SHOULD WEAKEN SOME AS THE DEEPER MOISTURE DEPARTS AND INVERSION HEIGHTS DROP TO 5-6KFT. WITH THE CLOUD FOCUSED IN THE DGZ...STILL SHOULD SEE GOOD SNOW RATIOS AND LIGHT SNOWFALL ACCUMULATIONS IN THE 1-3 INCH RANGE FOR THE KEWEENAW. SURFACE LOW DEVELOPS OVER EASTERN LAKE SUPERIOR MONDAY NIGHT AND ENHANCES A SURFACE TROUGH OVER THE CENTRAL AND WESTERN PORTIONS OF LAKE. MEANWHILE...DEEPER MOISTURE SLIDES THROUGH ASSOCIATED WITH A SHORTWAVE MOVING THROUGH THE NORTHERN STREAM NORTHWEST FLOW. THERE WILL LIKELY BE A STRONGER...DOMINATE LES BAND ASSOCIATED WITH THIS TROUGH...BUT MODELS VARY ON THE EXACT LOCATION. AREA NEAR THE TIP OF THE KEWEENAW WILL HAVE THE BEST CHANCE FOR SEEING THIS BAND LATE MONDAY NIGHT INTO TUESDAY...SO WILL HIGHLIGHT HIGHER POPS/SNOWFALL THERE. LES SHOULD DIMINISH TUESDAY AFTERNOON...AS WEAK RIDGING ALOFT PRODUCES DRIER AIR AND WAA AHEAD OF THE NEXT SHORTWAVE. THE NEXT SHORTWAVE AND ASSOCIATED CLIPPER LOW WILL MOVE ACROSS THE CWA ON WEDNESDAY INTO WEDNESDAY EVENING. AS IS NORMALLY THE CASE...THE GFS IS ON THE FAST SIDE AND THE ECMWF/GEM ARE ABOUT 6-12HRS BEHIND. WILL FOLLOW THAT IDEA FOR POPS AND THINK MOST AREAS WILL SEE A DUSTING TO AN INCH OF SYNOPTIC SNOW. POLAR VORTEX IS EXPECTED TO DROP SOUTH RIGHT BEHIND THIS WAVE AND LEAD TO SOME OF THE COLDEST TEMPERATURES OF THE WINTER SEASON FOR UPPER MICHIGAN. MODELS HAVE BEEN STRUGGLING WITH THIS PERIOD...DUE TO THE PHASING OF THE NORTHERN/SOUTHERN STREAMS OF THE UPPER JET IN THE EASTERN CONUS ON THURSDAY...BUT THE GENERAL IDEA OF COLD WEATHER IS THERE. THE HPC PREFERRED BLEND OF ECMWF/ECENS MEAN SEEMS TO BE THE WAY TO GO WITH THE GFS JUMPING 15C AT H850 FROM RUN TO RUN. THIS COLD AIR...H850 TEMPS ON THE ECMWF IN THE MID -20S WILL EASILY LEAD TO LAKE EFFECT SNOW IN THE NORTHWEST WIND LOCATIONS. DELTA-T VALUES SHOULD BE FAIRLY IMPRESSIVE...IN THE UPPER 20S BUT THE COLD AIR WILL PUSH THE DGZ TOWARDS THE SURFACE AND PRODUCE A LESS FLUFFY /PLATES OR COLUMNS/ SNOW. WILL KEEP THE SAME IDEA AS THE PREVIOUS SHIFT OF HIGH END LIKELY POPS FOR WEDNESDAY NIGHT INTO FRIDAY FOR NORTHWEST AND EVENTUALLY WEST-NORTHWEST FAVORED LOCATIONS. ONE FINAL ITEM TO NOTE DURING THIS PERIOD IS THE 00Z GEM/GFS ARE BOTH SHOWING A CLIPPER MOVING THROUGH THE UPPER MISSISSIPPI VALLEY ON THURSDAY INTO THURSDAY NIGHT...WHILE THE ECMWF IS ABOUT A DAY LATER AND MAY BRUSH THE CWA. HIGHS FOR THE PERIOD WILL BE IN THE TEENS TO MIDDLE 20S...WITH THE COLDEST HIGHS EXPECTED ON THURSDAY/FRIDAY. LOWS WILL ALSO BE NEAR NORMAL...WITH VALUES IN THE SINGLE DIGITS TO MIDDLE TEENS ABOVE ZERO. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1246 PM EST SAT JAN 12 2013 MVFR CONDITIONS ARE COMMON...EXCEPT HIGH END MVFR TO LOW END VFR CEILINGS AT SAW /THANKS TO THE DOWNSLOPE CONDITIONS AT SAW/. STRONG WSW GUSTS OF 25 TO 33KTS CONTINUE AT ALL 3 SITES...STRONGEST AT CMX GIVEN THE HIGHER ELEVATION AND MORE FAVORABLE WIND DIRECTION...AND LOCATION CLOSER TO THE EXITING SURFACE LOW. THE STRONG GUSTY WINDS WILL DIMINISH SIGNIFICANTLY AROUND SUNSET...AS THE LOW QUICKLY SHIFTS INTO WESTERN QUEBEC. SNOW SHOWERS EVIDENT ON THE DLH RADAR WILL SLOWLY PUSH ACROSS W UPPER MI THIS AFTERNOON...WITH THE CONTINUED STRONG WINDS BRINGING THE POTENTIAL FOR BLOWING SNOW TO MAINLY CMX PRIOR TO 02Z. IFR TO LOW MVFR VIS CAN THEN BE EXPECTED TO LINGER THROUGH THE MID MORNING HOURS AT CMX...WITH MAINLY MVFR CONDITIONS TO VFR CONDITIONS AT IWD AND SAW RESPECTIVELY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 534 AM EST SAT JAN 12 2013 LOW PRESSURE ACROSS NE MN WILL MOVE NORTHEAST TO JAMES BAY LATE TODAY BRINGING GALES ACROSS LAKE SUPERIOR. STRONG SW GALES OF 35 WILL DEVELOP TOWARD DAYBREAK ACROSS THE WESTERN LAKE BEHIND THE COLD FRONT AND INCREASE TO 40-45KTS. EXPECT THE GALES TO DIMINISH AS THE STRONGEST WINDS SLOWLY EDGE SE...AS WINDS BEGIN TO TURN W BY LATE AFTERNOON. A TROUGH AVERAGING WILL LINGER ACROSS LAKE SUPERIOR THROUGH SUNDAY...BEFORE SLOWLY WEAKENING AS STRONGER 30.4 INCH HIGH PRESSURE EXPANDS ACROSS CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES THROUGH MONDAY. NW WINDS COULD AGAIN GUST TO NEAR 30KTS OVER SE LS SUNDAY NIGHT. LOW PRESSURE OVER MANITOBA AND ND TUESDAY NIGHT WILL LIKELY PUSH ACROSS ONTARIO AND THE UPPER GREAT LAKES ON WEDNESDAY. ANOTHER PERIOD OF SW-W 30-35KTS WINDS WILL BE POSSIBLE TUESDAY AFTERNOON INTO THE EVENING HOURS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST MONDAY FOR MIZ001-003. WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST MONDAY FOR MIZ002. LAKE SUPERIOR... GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162- 240>246-263>267. LAKE MICHIGAN... GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LMZ248-250. GALE WARNING UNTIL 5 PM EST THIS AFTERNOON FOR LMZ221. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...KF MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
643 AM EST SAT JAN 12 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 534 AM EST SAT JAN 12 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM NW ONTARIO INTO THE SW CONUS AND A RIDGE OVER THE EAST RESULTING IN SW FLOW FROM THE SRN PLAINS INTO THE WRN GREAT LAKES. A SHEARED SHORTWAVE TROUGH WAS LIFTING NORTHEAST THROUGH NRN MN. AT THE SFC...A 993 MB LOW WAS LOCATED OVER THE MN ARROWHEAD WITH A COLD FRONT EXTENDING TO THE SSE THROUGH NW INTO CNTRL WI. VERY MILD SSW FLOW AHEAD OF THE FRONT HAS PUSHED TEMPS INTO THE LOWER 40S ACROSS MOST OF UPPER MI. GUSTY SW WINDS HAVE DEVELOPED BEHIND THE COLD FRONT AS A 5MB/3HR PRES RISE MAX TRAILS THE FRONT OVER SRN MN. RADARS INDICATED AREAS OF LIGHT PCPN OVER ERN MN INTO NW WI WITH NO RETURNS TO THE EAST. MAIN FCST CONCERNS ARE WINDS AND LAKE EFFECT SNOW POTENTIAL. TODAY...MODELS HAVE BEEN CONSISTENT WITH THE LOW QUICKLY LIFTING NORTHEAST TO JAMES BAY BY LATE TODAY. THIS WILL DRAG THE COLD FRONT THROUGH THE CWA BY 18Z BRINGING THE STRONGEST ISALLOBARIC GRADIENT THROUGH THE WEST HALF OF UPPER MICHIGAN THIS MORNING. WITH STRONG CAA AND INCREASE IN MIXED LAYER DEPTH...GUSTY WINDS IN THE 25 TO 35 MPH RANGE ARE EXPECTED OVER MOST OF THE REGION. SINCE THE SW WINDS ARE MAINLY PARALLEL TO THE KEWEENAW PENINSULA THE STRONGER GUSTS ARE EXPECTED DURING THE AFTERNOON AS WINDS VEER MORE TO THE WSW. THIS WOULD BRING THE STRONGEST GUSTS MAINLY ACROSS THE WESTERN SHORE OF THE KEWEENAW. A WIND ADVISORY IS IN EFFECT WHICH HIGHLIGHTS THESE LOCATIONS. BY THE TIME THAT WINDS VEER TO THE WEST WHICH WOULD FAVOR LOCATIONS IN THE HIGHER TERRAIN AROUND CMX...THE GRADIENT WEAKENS. LAKE INDUCED CAPE VALUES CLIMB QUICKLY TO AROUND 300-400 J/KG BY LATE AFTERNOON AS 850 MB TEMPS FALL TO NEAR -15C. THE STRONGEST LOW LEVEL CONVERGENCE AND GREATEST LES IS EXPECTED TO FOCUS TOWARD THE NRN PORTION OF THE KEWEENAW....FROM CMX NORTHWARD. TONIGHT...INSTABILITY OVER THE LAKE WILL INCREASE AS 850 MB TEMPS DROP TO AROUND -18C. THE HIGHER RES MODELS SUGGEST THAT EVEN AS THE WINDS OVER WRN LAKE SUPERIOR VEER MORE TO THE NW...LAKE INDUCED TROUGHING WILL KEEP THE CONVERGENT WINDS OVER THE KEWEENAW. EVEN THOUGH INVERSION HEIGHTS ARE ONLY FCST NEAR 4K FT...WITH THE MOISTURE DEPTH TO AT LEAST 7K FT...AT LEAST MODERATE INTENSITY LES IS EXPECTED THAT COULD BRING 2 TO 4 INCHES TO LOCATIONS FROM NE ONTONAGON COUNTY THROUGH THE HIGHER TERRAIN OF THE KEWEENAW PENINSULA. A LES ADVISORY WAS POSTED WHICH EXTENDS THROUGH SUNDAY NIGHT(DETAILS IN SUBSEQUENT DISCUSSION). A SHORTWAVE MOVING TOWARD THE GREAT LAKE FROM THE CNTRL PLAINS ALONG WITH UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 170 KT 300 MB JET INTO NRN ONTARIO WILL ALSO SUPPORT AN AREA OF LIGHT SNOW THAT WILL GRAZE THE SE PORTIONS OF THE CWA. SINCE THE HEAVIER PCPN IS EXPECTED TO THE SOUTH...ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW AN INCH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 534 AM EST SAT JAN 12 2013 AREA WILL BE ENTERING BACK INTO A MORE WINTER TIME PATTERN TODAY...WHICH WILL CONTINUE THROUGH THE LONG TERM PERIOD. SYSTEM MOVING THROUGH THE LOWER GREAT LAKES TONIGHT INTO SUNDAY HAS HAS SHIFTED A LITTLE MORE TO THE NORTHWEST OVER THE LAST FEW RUNS AND NOW BRUSHES THE COUNTIES NEAR LAKE MICHIGAN WITH SOME LIGHT SNOW SUNDAY MORNING. THIS NORTHWEST SHIFT HAS CAUSES THE DEEPER MOISTURE WITH A LEFT OVER SHORTWAVE FROM THE LOW CURRENTLY IN MN TO REMAIN JUST TO THE WEST OF LAKE SUPERIOR ON SUNDAY MORNING AND THE FIRST PART OF THE AFTERNOON. THIS LEADS TO SOME CONCERN FOR THE INITIAL LAKE EFFECT FROM LINGERING SURFACE TROUGH OVER SOUTHERN LAKE SUPERIOR. SINCE THE COLD AIR SURGE EXPECTED TODAY INTO TONIGHT WILL BE FAIRLY SHALLOW...IT WILL SETUP A VERY STRONG INVERSION TONIGHT AROUND H800 OR 5KFT. THUS...DO EXPECT LAKE EFFECT TO BE OCCURRING OVER THE WEST-NORTHWEST FAVORED LOCATIONS IN THE WESTERN U.P. BUT HAVE SOME CONCERNS ON STRENGTH TO START THE PERIOD. ON THE POSITIVE SIDE...THE BEST FORCING WILL BE FOCUSED IN THE DGZ...BUT THERE IS SOME SHEAR IN THE CLOUD LAYER...SFC-H925 WINDS OUT OF THE NORTHWEST AND H850 WINDS OUT OF THE WEST IN THE MORNING AND THEN SOUTHWEST IN THE AFTERNOON. WONDERING IF THIS WILL KEEP THE FOCUS AWAY FROM A DOMINATE BAND IN MORE GENERAL MULTIBAND LAKE EFFECT. LAKE EFFECT SNOW PARAMETER...WHICH HAS DONE A GOOD JOB HIGHLIGHTING THE FEW LAKE EFFECT EVENTS WE HAVE HAD THIS SEASON...KEEPS VALUES LIMITED DURING THE MORNING HOURS AND WILL KEEP SNOWFALL AMOUNTS LIGHTER. ONCE THE SURFACE LOW SLIDES NORTHEAST INTO WESTERN QUEBEC SUNDAY AFTERNOON AND EVENING...THEN THE SURFACE TROUGH WILL SLIDE SOUTH SLIGHTLY LEADING TO LESS SHEAR AND RISING INVERSION HEIGHTS TO 6-7KFT DUE TO DEEPER MOISTURE IN MN BEING DRAGGED THROUGH THE WESTERN CWA. LAKE EFFECT SNOW PARAMETER PEAKS TO 2 IN THIS PERIOD...SO EXPECT INTENSITY OF THE LAKE EFFECT TO FOLLOW SUIT. AT THIS POINT...THINK IT WILL BE IN NORTHWEST FAVORED LOCATIONS ALTHOUGH HIGHER RESOLUTION MODELS ARE TRYING TO HINT AT ENHANCED CONVERGENCE IN THE HOUGHTON/ONTONAGON/GOGEBIC COUNTY AREA. CHECKLIST GIVES 3-5IN PER 12HRS FOR SUNDAY AND SUNDAY NIGHT AND THAT SEEMS TO FIT WELL WITH THE GOING FORECAST...AS SNOW RATIOS WILL BE IN THE 20-30 TO 1 RANGE. WITH TOTAL SNOW FROM TONIGHT THROUGH SUNDAY NIGHT OF 7 TO LOCALLY 14 INCHES...WILL ISSUE AN ADVISORY FOR KEWEENAW THROUGH ONTONAGON COUNTIES. WILL NEED TO WATCH GOGEBIC COUNTY NEAR THE PORCUPINE MOUNTAINS...AS ARE HINTS OF ENHANCED CONVERGENCE FOR HIGHER SNOWFALL AMOUNTS THERE. FARTHER EAST...WITH THE LIGHT SYNOPTIC SNOW LEAVING EARLY SUNDAY AFTERNOON...TRANSITION WILL OCCUR TO LAKE EFFECT IN THE NORTHWEST WIND BELTS IN THE AFTERNOON...AS THE SURFACE TROUGH SHIFTS WINDS. THERE TOO...AMOUNTS WILL BE LIGHT TO MODERATE ON SUNDAY AFTERNOON INTO THE EVENING...BUT COULD PEAK UP SOME AFTER MIDNIGHT WHEN THE INVERSION HEIGHTS RISE. MAY NEED AN ADVISORY ON FUTURE SHIFTS FOR THE SUN AFTERNOON/NIGHT PERIOD. SURFACE TROUGH THEN SHIFTS NORTH ON MONDAY...PUSHING THE SNOW OFFSHORE OVER THE EAST AND FOCUSES IT OVER THE KEWEENAW IN THE WEST. INTENSITY SHOULD WEAKEN SOME AS THE DEEPER MOISTURE DEPARTS AND INVERSION HEIGHTS DROP TO 5-6KFT. WITH THE CLOUD FOCUSED IN THE DGZ...STILL SHOULD SEE GOOD SNOW RATIOS AND LIGHT SNOWFALL ACCUMULATIONS IN THE 1-3 INCH RANGE FOR THE KEWEENAW. SURFACE LOW DEVELOPS OVER EASTERN LAKE SUPERIOR MONDAY NIGHT AND ENHANCES A SURFACE TROUGH OVER THE CENTRAL AND WESTERN PORTIONS OF LAKE. MEANWHILE...DEEPER MOISTURE SLIDES THROUGH ASSOCIATED WITH A SHORTWAVE MOVING THROUGH THE NORTHERN STREAM NORTHWEST FLOW. THERE WILL LIKELY BE A STRONGER...DOMINATE LES BAND ASSOCIATED WITH THIS TROUGH...BUT MODELS VARY ON THE EXACT LOCATION. AREA NEAR THE TIP OF THE KEWEENAW WILL HAVE THE BEST CHANCE FOR SEEING THIS BAND LATE MONDAY NIGHT INTO TUESDAY...SO WILL HIGHLIGHT HIGHER POPS/SNOWFALL THERE. LES SHOULD DIMINISH TUESDAY AFTERNOON...AS WEAK RIDGING ALOFT PRODUCES DRIER AIR AND WAA AHEAD OF THE NEXT SHORTWAVE. THE NEXT SHORTWAVE AND ASSOCIATED CLIPPER LOW WILL MOVE ACROSS THE CWA ON WEDNESDAY INTO WEDNESDAY EVENING. AS IS NORMALLY THE CASE...THE GFS IS ON THE FAST SIDE AND THE ECMWF/GEM ARE ABOUT 6-12HRS BEHIND. WILL FOLLOW THAT IDEA FOR POPS AND THINK MOST AREAS WILL SEE A DUSTING TO AN INCH OF SYNOPTIC SNOW. POLAR VORTEX IS EXPECTED TO DROP SOUTH RIGHT BEHIND THIS WAVE AND LEAD TO SOME OF THE COLDEST TEMPERATURES OF THE WINTER SEASON FOR UPPER MICHIGAN. MODELS HAVE BEEN STRUGGLING WITH THIS PERIOD...DUE TO THE PHASING OF THE NORTHERN/SOUTHERN STREAMS OF THE UPPER JET IN THE EASTERN CONUS ON THURSDAY...BUT THE GENERAL IDEA OF COLD WEATHER IS THERE. THE HPC PREFERRED BLEND OF ECMWF/ECENS MEAN SEEMS TO BE THE WAY TO GO WITH THE GFS JUMPING 15C AT H850 FROM RUN TO RUN. THIS COLD AIR...H850 TEMPS ON THE ECMWF IN THE MID -20S WILL EASILY LEAD TO LAKE EFFECT SNOW IN THE NORTHWEST WIND LOCATIONS. DELTA-T VALUES SHOULD BE FAIRLY IMPRESSIVE...IN THE UPPER 20S BUT THE COLD AIR WILL PUSH THE DGZ TOWARDS THE SURFACE AND PRODUCE A LESS FLUFFY /PLATES OR COLUMNS/ SNOW. WILL KEEP THE SAME IDEA AS THE PREVIOUS SHIFT OF HIGH END LIKELY POPS FOR WEDNESDAY NIGHT INTO FRIDAY FOR NORTHWEST AND EVENTUALLY WEST-NORTHWEST FAVORED LOCATIONS. ONE FINAL ITEM TO NOTE DURING THIS PERIOD IS THE 00Z GEM/GFS ARE BOTH SHOWING A CLIPPER MOVING THROUGH THE UPPER MISSISSIPPI VALLEY ON THURSDAY INTO THURSDAY NIGHT...WHILE THE ECMWF IS ABOUT A DAY LATER AND MAY BRUSH THE CWA. HIGHS FOR THE PERIOD WILL BE IN THE TEENS TO MIDDLE 20S...WITH THE COLDEST HIGHS EXPECTED ON THURSDAY/FRIDAY. LOWS WILL ALSO BE NEAR NORMAL...WITH VALUES IN THE SINGLE DIGITS TO MIDDLE TEENS ABOVE ZERO. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 641 AM EST SAT JAN 12 2013 CONDITIONS AT SAW SHOULD QUICKLY IMPROVE INTO THE MVFR RANGE THIS MORNING AT SAW AS WINDS VEER FROM THE S TO A MORE DOWNSLOPE SW DIRECTION. A STRONG COLD FRONT WILL PUSH THROUGH THE AREA THIS MORNING BRINGING GUSTY SOUTHWEST WINDS. THE STRONGEST GUSTS WILL BE AT OROGRAPHICALLY FAVORED CMX WHERE GUSTS COULD REACH 40KTS. AS TEMPERATURES FALL THROUGH THE DAY...LAKE EFFECT -SHSN SHOULD AFFECT CMX WITH ANY LIGHT ACCUMULATIONS RESULTING IN BLSN BEFORE WINDS BEGIN TO DIMINISH TOWARDS EVENING. LAKE EFFECT SNOW WITH PREDOMINANT IFR VSBY IS EXPECTED TO CONTINUE THROUGH TONIGHT. AT IWD/SAW MAINLY MVFR CONDITIONS SHOULD PREVAIL THROUGH THE FCST PERIOD. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 534 AM EST SAT JAN 12 2013 LOW PRESSURE ACROSS NE MN WILL MOVE NORTHEAST TO JAMES BAY LATE TODAY BRINGING GALES ACROSS LAKE SUPERIOR. STRONG SW GALES OF 35 WILL DEVELOP TOWARD DAYBREAK ACROSS THE WESTERN LAKE BEHIND THE COLD FRONT AND INCREASE TO 40-45KTS. EXPECT THE GALES TO DIMINISH AS THE STRONGEST WINDS SLOWLY EDGE SE...AS WINDS BEGIN TO TURN W BY LATE AFTERNOON. A TROUGH AVERAGING WILL LINGER ACROSS LAKE SUPERIOR THROUGH SUNDAY...BEFORE SLOWLY WEAKENING AS STRONGER 30.4 INCH HIGH PRESSURE EXPANDS ACROSS CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES THROUGH MONDAY. NW WINDS COULD AGAIN GUST TO NEAR 30KTS OVER SE LS SUNDAY NIGHT. LOW PRESSURE OVER MANITOBA AND ND TUESDAY NIGHT WILL LIKELY PUSH ACROSS ONTARIO AND THE UPPER GREAT LAKES ON WEDNESDAY. ANOTHER PERIOD OF SW-W 30-35KTS WINDS WILL BE POSSIBLE TUESDAY AFTERNOON INTO THE EVENING HOURS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST MONDAY FOR MIZ001-003. WIND ADVISORY FROM NOON TODAY TO 8 PM EST THIS EVENING FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST MONDAY FOR MIZ002. LAKE SUPERIOR... GALE WARNING FROM 10 AM EST /9 AM CST/ THIS MORNING TO 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ240>246-265>267. GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162- 263-264. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR LMZ221-248- 250. GALE WARNING FROM 11 AM THIS MORNING TO 9 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
535 AM EST SAT JAN 12 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 534 AM EST SAT JAN 12 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM NW ONTARIO INTO THE SW CONUS AND A RIDGE OVER THE EAST RESULTING IN SW FLOW FROM THE SRN PLAINS INTO THE WRN GREAT LAKES. A SHEARED SHORTWAVE TROUGH WAS LIFTING NORTHEAST THROUGH NRN MN. AT THE SFC...A 993 MB LOW WAS LOCATED OVER THE MN ARROWHEAD WITH A COLD FRONT EXTENDING TO THE SSE THROUGH NW INTO CNTRL WI. VERY MILD SSW FLOW AHEAD OF THE FRONT HAS PUSHED TEMPS INTO THE LOWER 40S ACROSS MOST OF UPPER MI. GUSTY SW WINDS HAVE DEVELOPED BEHIND THE COLD FRONT AS A 5MB/3HR PRES RISE MAX TRAILS THE FRONT OVER SRN MN. RADARS INDICATED AREAS OF LIGHT PCPN OVER ERN MN INTO NW WI WITH NO RETURNS TO THE EAST. MAIN FCST CONCERNS ARE WINDS AND LAKE EFFECT SNOW POTENTIAL. TODAY...MODELS HAVE BEEN CONSISTENT WITH THE LOW QUICKLY LIFTING NORTHEAST TO JAMES BAY BY LATE TODAY. THIS WILL DRAG THE COLD FRONT THROUGH THE CWA BY 18Z BRINGING THE STRONGEST ISALLOBARIC GRADIENT THROUGH THE WEST HALF OF UPPER MICHIGAN THIS MORNING. WITH STRONG CAA AND INCREASE IN MIXED LAYER DEPTH...GUSTY WINDS IN THE 25 TO 35 MPH RANGE ARE EXPECTED OVER MOST OF THE REGION. SINCE THE SW WINDS ARE MAINLY PARALLEL TO THE KEWEENAW PENINSULA THE STRONGER GUSTS ARE EXPECTED DURING THE AFTERNOON AS WINDS VEER MORE TO THE WSW. THIS WOULD BRING THE STRONGEST GUSTS MAINLY ACROSS THE WESTERN SHORE OF THE KEWEENAW. A WIND ADVISORY IS IN EFFECT WHICH HIGHLIGHTS THESE LOCATIONS. BY THE TIME THAT WINDS VEER TO THE WEST WHICH WOULD FAVOR LOCATIONS IN THE HIGHER TERRAIN AROUND CMX...THE GRADIENT WEAKENS. LAKE INDUCED CAPE VALUES CLIMB QUICKLY TO AROUND 300-400 J/KG BY LATE AFTERNOON AS 850 MB TEMPS FALL TO NEAR -15C. THE STRONGEST LOW LEVEL CONVERGENCE AND GREATEST LES IS EXPECTED TO FOCUS TOWARD THE NRN PORTION OF THE KEWEENAW....FROM CMX NORTHWARD. TONIGHT...INSTABILITY OVER THE LAKE WILL INCREASE AS 850 MB TEMPS DROP TO AROUND -18C. THE HIGHER RES MODELS SUGGEST THAT EVEN AS THE WINDS OVER WRN LAKE SUPERIOR VEER MORE TO THE NW...LAKE INDUCED TROUGHING WILL KEEP THE CONVERGENT WINDS OVER THE KEWEENAW. EVEN THOUGH INVERSION HEIGHTS ARE ONLY FCST NEAR 4K FT...WITH THE MOISTURE DEPTH TO AT LEAST 7K FT...AT LEAST MODERATE INTENSITY LES IS EXPECTED THAT COULD BRING 2 TO 4 INCHES TO LOCATIONS FROM NE ONTONAGON COUNTY THROUGH THE HIGHER TERRAIN OF THE KEWEENAW PENINSULA. A LES ADVISORY WAS POSTED WHICH EXTENDS THROUGH SUNDAY NIGHT(DETAILS IN SUBSEQUENT DISCUSSION). A SHORTWAVE MOVING TOWARD THE GREAT LAKE FROM THE CNTRL PLAINS ALONG WITH UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 170 KT 300 MB JET INTO NRN ONTARIO WILL ALSO SUPPORT AN AREA OF LIGHT SNOW THAT WILL GRAZE THE SE PORTIONS OF THE CWA. SINCE THE HEAVIER PCPN IS EXPECTED TO THE SOUTH...ACCUMULATIONS ARE EXPECTED TO REMAIN BELOW AN INCH. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 534 AM EST SAT JAN 12 2013 AREA WILL BE ENTERING BACK INTO A MORE WINTER TIME PATTERN TODAY...WHICH WILL CONTINUE THROUGH THE LONG TERM PERIOD. SYSTEM MOVING THROUGH THE LOWER GREAT LAKES TONIGHT INTO SUNDAY HAS HAS SHIFTED A LITTLE MORE TO THE NORTHWEST OVER THE LAST FEW RUNS AND NOW BRUSHES THE COUNTIES NEAR LAKE MICHIGAN WITH SOME LIGHT SNOW SUNDAY MORNING. THIS NORTHWEST SHIFT HAS CAUSES THE DEEPER MOISTURE WITH A LEFT OVER SHORTWAVE FROM THE LOW CURRENTLY IN MN TO REMAIN JUST TO THE WEST OF LAKE SUPERIOR ON SUNDAY MORNING AND THE FIRST PART OF THE AFTERNOON. THIS LEADS TO SOME CONCERN FOR THE INITIAL LAKE EFFECT FROM LINGERING SURFACE TROUGH OVER SOUTHERN LAKE SUPERIOR. SINCE THE COLD AIR SURGE EXPECTED TODAY INTO TONIGHT WILL BE FAIRLY SHALLOW...IT WILL SETUP A VERY STRONG INVERSION TONIGHT AROUND H800 OR 5KFT. THUS...DO EXPECT LAKE EFFECT TO BE OCCURRING OVER THE WEST-NORTHWEST FAVORED LOCATIONS IN THE WESTERN U.P. BUT HAVE SOME CONCERNS ON STRENGTH TO START THE PERIOD. ON THE POSITIVE SIDE...THE BEST FORCING WILL BE FOCUSED IN THE DGZ...BUT THERE IS SOME SHEAR IN THE CLOUD LAYER...SFC-H925 WINDS OUT OF THE NORTHWEST AND H850 WINDS OUT OF THE WEST IN THE MORNING AND THEN SOUTHWEST IN THE AFTERNOON. WONDERING IF THIS WILL KEEP THE FOCUS AWAY FROM A DOMINATE BAND IN MORE GENERAL MULTIBAND LAKE EFFECT. LAKE EFFECT SNOW PARAMETER...WHICH HAS DONE A GOOD JOB HIGHLIGHTING THE FEW LAKE EFFECT EVENTS WE HAVE HAD THIS SEASON...KEEPS VALUES LIMITED DURING THE MORNING HOURS AND WILL KEEP SNOWFALL AMOUNTS LIGHTER. ONCE THE SURFACE LOW SLIDES NORTHEAST INTO WESTERN QUEBEC SUNDAY AFTERNOON AND EVENING...THEN THE SURFACE TROUGH WILL SLIDE SOUTH SLIGHTLY LEADING TO LESS SHEAR AND RISING INVERSION HEIGHTS TO 6-7KFT DUE TO DEEPER MOISTURE IN MN BEING DRAGGED THROUGH THE WESTERN CWA. LAKE EFFECT SNOW PARAMETER PEAKS TO 2 IN THIS PERIOD...SO EXPECT INTENSITY OF THE LAKE EFFECT TO FOLLOW SUIT. AT THIS POINT...THINK IT WILL BE IN NORTHWEST FAVORED LOCATIONS ALTHOUGH HIGHER RESOLUTION MODELS ARE TRYING TO HINT AT ENHANCED CONVERGENCE IN THE HOUGHTON/ONTONAGON/GOGEBIC COUNTY AREA. CHECKLIST GIVES 3-5IN PER 12HRS FOR SUNDAY AND SUNDAY NIGHT AND THAT SEEMS TO FIT WELL WITH THE GOING FORECAST...AS SNOW RATIOS WILL BE IN THE 20-30 TO 1 RANGE. WITH TOTAL SNOW FROM TONIGHT THROUGH SUNDAY NIGHT OF 7 TO LOCALLY 14 INCHES...WILL ISSUE AN ADVISORY FOR KEWEENAW THROUGH ONTONAGON COUNTIES. WILL NEED TO WATCH GOGEBIC COUNTY NEAR THE PORCUPINE MOUNTAINS...AS ARE HINTS OF ENHANCED CONVERGENCE FOR HIGHER SNOWFALL AMOUNTS THERE. FARTHER EAST...WITH THE LIGHT SYNOPTIC SNOW LEAVING EARLY SUNDAY AFTERNOON...TRANSITION WILL OCCUR TO LAKE EFFECT IN THE NORTHWEST WIND BELTS IN THE AFTERNOON...AS THE SURFACE TROUGH SHIFTS WINDS. THERE TOO...AMOUNTS WILL BE LIGHT TO MODERATE ON SUNDAY AFTERNOON INTO THE EVENING...BUT COULD PEAK UP SOME AFTER MIDNIGHT WHEN THE INVERSION HEIGHTS RISE. MAY NEED AN ADVISORY ON FUTURE SHIFTS FOR THE SUN AFTERNOON/NIGHT PERIOD. SURFACE TROUGH THEN SHIFTS NORTH ON MONDAY...PUSHING THE SNOW OFFSHORE OVER THE EAST AND FOCUSES IT OVER THE KEWEENAW IN THE WEST. INTENSITY SHOULD WEAKEN SOME AS THE DEEPER MOISTURE DEPARTS AND INVERSION HEIGHTS DROP TO 5-6KFT. WITH THE CLOUD FOCUSED IN THE DGZ...STILL SHOULD SEE GOOD SNOW RATIOS AND LIGHT SNOWFALL ACCUMULATIONS IN THE 1-3 INCH RANGE FOR THE KEWEENAW. SURFACE LOW DEVELOPS OVER EASTERN LAKE SUPERIOR MONDAY NIGHT AND ENHANCES A SURFACE TROUGH OVER THE CENTRAL AND WESTERN PORTIONS OF LAKE. MEANWHILE...DEEPER MOISTURE SLIDES THROUGH ASSOCIATED WITH A SHORTWAVE MOVING THROUGH THE NORTHERN STREAM NORTHWEST FLOW. THERE WILL LIKELY BE A STRONGER...DOMINATE LES BAND ASSOCIATED WITH THIS TROUGH...BUT MODELS VARY ON THE EXACT LOCATION. AREA NEAR THE TIP OF THE KEWEENAW WILL HAVE THE BEST CHANCE FOR SEEING THIS BAND LATE MONDAY NIGHT INTO TUESDAY...SO WILL HIGHLIGHT HIGHER POPS/SNOWFALL THERE. LES SHOULD DIMINISH TUESDAY AFTERNOON...AS WEAK RIDGING ALOFT PRODUCES DRIER AIR AND WAA AHEAD OF THE NEXT SHORTWAVE. THE NEXT SHORTWAVE AND ASSOCIATED CLIPPER LOW WILL MOVE ACROSS THE CWA ON WEDNESDAY INTO WEDNESDAY EVENING. AS IS NORMALLY THE CASE...THE GFS IS ON THE FAST SIDE AND THE ECMWF/GEM ARE ABOUT 6-12HRS BEHIND. WILL FOLLOW THAT IDEA FOR POPS AND THINK MOST AREAS WILL SEE A DUSTING TO AN INCH OF SYNOPTIC SNOW. POLAR VORTEX IS EXPECTED TO DROP SOUTH RIGHT BEHIND THIS WAVE AND LEAD TO SOME OF THE COLDEST TEMPERATURES OF THE WINTER SEASON FOR UPPER MICHIGAN. MODELS HAVE BEEN STRUGGLING WITH THIS PERIOD...DUE TO THE PHASING OF THE NORTHERN/SOUTHERN STREAMS OF THE UPPER JET IN THE EASTERN CONUS ON THURSDAY...BUT THE GENERAL IDEA OF COLD WEATHER IS THERE. THE HPC PREFERRED BLEND OF ECMWF/ECENS MEAN SEEMS TO BE THE WAY TO GO WITH THE GFS JUMPING 15C AT H850 FROM RUN TO RUN. THIS COLD AIR...H850 TEMPS ON THE ECMWF IN THE MID -20S WILL EASILY LEAD TO LAKE EFFECT SNOW IN THE NORTHWEST WIND LOCATIONS. DELTA-T VALUES SHOULD BE FAIRLY IMPRESSIVE...IN THE UPPER 20S BUT THE COLD AIR WILL PUSH THE DGZ TOWARDS THE SURFACE AND PRODUCE A LESS FLUFFY /PLATES OR COLUMNS/ SNOW. WILL KEEP THE SAME IDEA AS THE PREVIOUS SHIFT OF HIGH END LIKELY POPS FOR WEDNESDAY NIGHT INTO FRIDAY FOR NORTHWEST AND EVENTUALLY WEST-NORTHWEST FAVORED LOCATIONS. ONE FINAL ITEM TO NOTE DURING THIS PERIOD IS THE 00Z GEM/GFS ARE BOTH SHOWING A CLIPPER MOVING THROUGH THE UPPER MISSISSIPPI VALLEY ON THURSDAY INTO THURSDAY NIGHT...WHILE THE ECMWF IS ABOUT A DAY LATER AND MAY BRUSH THE CWA. HIGHS FOR THE PERIOD WILL BE IN THE TEENS TO MIDDLE 20S...WITH THE COLDEST HIGHS EXPECTED ON THURSDAY/FRIDAY. LOWS WILL ALSO BE NEAR NORMAL...WITH VALUES IN THE SINGLE DIGITS TO MIDDLE TEENS ABOVE ZERO. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY MORNING) ISSUED AT 534 AM EST SAT JAN 12 2013 AS SOUTHERLY WINDS INCREASE OVERNIGHT VISIBILITIES SHOULD SLOWLY IMPROVE AT CMX AND SAW. HOWEVER...CIGS WILL GENERALLY REMAIN IN THE LIFR RANGE. CONDITIONS SHOULD IMPROVE INTO THE MVFR RANGE ON SATURDAY BEHIND A STRONG COLD FRONT PUSHING THROUGH THE AREA. STRONG PRESSURE RISES AND A TIGHT PRESSURE GRADIENT WILL RESULT IN GUSTY WEST TO SOUTHWEST WINDS DURING THE DAY. THE STRONGEST GUSTS WILL BE AT OROGRAPHICALLY FAVORED CMX WHERE GUSTS COULD TOP 40KTS. AS TEMPERATURES FALL THROUGH THE DAY LAKE EFFECT -SHSN SHOULD AFFECT CMX WITH ANY LIGHT ACCUMULATIONS RESULTING IN BLSN BEFORE WINDS BEGIN TO DIMINISH TOWARDS EVENING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 534 AM EST SAT JAN 12 2013 LOW PRESSURE ACROSS NE MN WILL MOVE NORTHEAST TO JAMES BAY LATE TODAY BRINGING GALES ACROSS LAKE SUPERIOR. STRONG SW GALES OF 35 WILL DEVELOP TOWARD DAYBREAK ACROSS THE WESTERN LAKE BEHIND THE COLD FRONT AND INCREASE TO 40-45KTS. EXPECT THE GALES TO DIMINISH AS THE STRONGEST WINDS SLOWLY EDGE SE...AS WINDS BEGIN TO TURN W BY LATE AFTERNOON. A TROUGH AVERAGING WILL LINGER ACROSS LAKE SUPERIOR THROUGH SUNDAY...BEFORE SLOWLY WEAKENING AS STRONGER 30.4 INCH HIGH PRESSURE EXPANDS ACROSS CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES THROUGH MONDAY. NW WINDS COULD AGAIN GUST TO NEAR 30KTS OVER SE LS SUNDAY NIGHT. LOW PRESSURE OVER MANITOBA AND ND TUESDAY NIGHT WILL LIKELY PUSH ACROSS ONTARIO AND THE UPPER GREAT LAKES ON WEDNESDAY. ANOTHER PERIOD OF SW-W 30-35KTS WINDS WILL BE POSSIBLE TUESDAY AFTERNOON INTO THE EVENING HOURS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY FROM 5 PM THIS AFTERNOON TO 7 AM EST MONDAY FOR MIZ001-003. WIND ADVISORY FROM NOON TODAY TO 8 PM EST THIS EVENING FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 AM EST MONDAY FOR MIZ002. LAKE SUPERIOR... GALE WARNING FROM 10 AM EST /9 AM CST/ THIS MORNING TO 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ240>246-265>267. GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR LSZ162- 263-264. LAKE MICHIGAN... DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR LMZ221-248- 250. GALE WARNING FROM 11 AM THIS MORNING TO 9 PM EST THIS EVENING FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...MZ MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1225 PM CST SAT JAN 12 2013 .UPDATE... ISSUED AT 1212 PM CST SAT JAN 12 2013 COLD FRONT EXTENDS FROM JUST NORTHWEST OF FARMINGTON TO AROUND SALEM ILLINOIS AT THIS TIME. LATEST MODEL GUIDANCE HAS STRENGTHENED THE WARM NOSE ABOVE THE COLD AIR AT THE SURFACE FOR THIS EVENING...AND THIS IS BEARING OUT PRETTY WELL IN AMDAR SOUNDINGS FROM LAMBERT FIELD EARLIER THIS MORNING. RAP SOUNDINGS SHOW THE WARM NOSE OVER THE STL METRO AREA WILL BE AROUND 7C THROUGH THE EVENING HOURS...AND WITH THE COLD LAYER ONLY DROPPING TO BETWEEN -4C TO -5C IT DOESN`T LOOK LIKE THERE`S GOING TO BE ENOUGH COLD AIR TO FREEZE THE LIQUID ALOFT. FORECAST SOUNDINGS ALONG A LINE FROM ROLLA TO ST LOUIS TO LITCHFIELD ARE VERY SIMILAR. THEREFORE AM UPDATING THE FORECAST TO GO WITH MORE FREEZING RAIN THAN SLEET IN THESE AREAS THIS EVENING AND OVERNIGHT. REMAINDER OF THE WEATHER TYPES STILL LOOK GOOD WITH A SLEET/SNOW MIX OVER CENTRAL AND NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS WHERE COLD AIR WILL BE DEEPER...AND RAIN CHANGING TO FREEZING RAIN OVER SOUTHEAST MISSOURI AND SOUTH CENTRAL ILLINOIS. DEBATING WHETHER OR NOT TO EXTEND THE ADVISORY ANOTHER ROW OF COUNTIES TO THE SOUTHEAST TO ACCOUNT FOR THE POTENTIAL OF MORE FREEZING RAIN ACCUMULATION...AND WILL LIKELY HAVE TO EXTEND THE TIME OF THE ADVISORY OUT BEYOND 06Z TONIGHT. CARNEY && .SHORT TERM... ISSUED AT 330 AM CST SAT JAN 12 2013 (TODAY) A STRONG CDFNT WILL MOVE THROUGH MOST OF THE CWA TODAY BEFORE IT BEGINS TO STALL IN SERN MO LATER TODAY DUE TO A WAVE OF LOW PRESSURE WHICH DVLPS UPSTREAM ALONG THE FRONT IN RESPONSE TO AN UPPER LEVEL DISTURBANCE MOVING OVER THE BDRY IN TX/OK. MANY LOCATIONS WILL EXPERIENCE NEARLY STEADY OR FALLING TEMPERATURES THROUGH THE DAY BECAUSE OF THE STRENGTH OF THE CDFNT AND THE TIMING OF ITS PASSAGE DURING DAYLIGHT HOURS. STRONG ISENTROPIC ASCENT IS MOST PRONOUNCED ALONG THE 295-305K SFCS THIS AFTN AHEAD OF AN APPROACHING SHORTWAVE. THIS ASCENT WILL OCCUR IN THE PRESENCE OF A GREAT DEAL OF MOISTURE FOR MID-JANUARY. IN PARTICULAR...STANDARDIZED ANOMALY PLOTS OF PW FROM THE 12/00Z GFS AND 12/03Z SREF SHOW ANOMALIES OF BETWEEN +1 AND +4 STDDEV ACROSS THE ENTIRE CWA WITH THE HIGHEST VALUES ACROSS THE SERN CWA BY 00Z. THE NET RESULT OF THE FNTL PASSAGE TODAY ALONG WITH SEVERAL HOURS OF ASCENT AND PLENTY OF MOISTURE WILL BE PCPN OF VARIOUS TYPES OCCURRING FROM THIS AFTN THROUGH TONIGHT. THE BULK OF THE PCPN AS WELL AS THE GREATEST VARIETY OF PTYPES WILL OCCUR TONIGHT AND THIS IS DISCUSSED IN FURTHER DETAIL BELOW. FOR THIS AFTN...BUFKIT PROFILES SUPPORT RAIN WHICH MAY BEGIN CHANGING TO SNOW AND ICE PELLETS ACROSS THE FAR WRN AND NWRN CWA LATE IN THE AFTN. SCT THUNDERSTORMS WILL ALSO BE POSSIBLE ACROSS THE SERN CWA SINCE MODELS SHOW SOME MUCAPE ALONG WITH STRONG MOISTURE TRANSPORT ALOFT. KANOFSKY && .LONG TERM... ISSUED AT 357 AM CST SAT JAN 12 2013 (TONIGHT AND SUNDAY) THE FORECAST PACKAGE...AS IT STANDS NOW...WILL BE DOMINATED BY WHAT HAPPENS IN THIS PERIOD. BASIC PREMISE OF THE FORECAST REMAINS THE SAME...BUT THERE HAVE BEEN SOME MODEL TRENDS IN SOME AREAS THAT COULD MAKE A SIGNIFICANT IMPACT TO THE FORECAST. MODELS CONTINUE TO SHOW SW UPPER LEVEL FLOW PATTERN WITH A SIGNIFICANT PIECE OF ENERGY BREAKING APART FROM THE BASE OF THE MAIN LONGWAVE TROF IN THE FOUR CORNERS REGION TODAY AND RACING NEWD THRU OUR AREA THIS EVENING. IN ADDITION TO THE LIFT PROVIDED BY THIS SHORTWAVE WILL BE SEVERAL OTHER STRONG LIFTING MECHANISMS FROM RIGHT ENTRANCE REGION OF AN UPPER JET...FRONTOGENESIS AT H850-700...WAA... AND CONVERGENCE FROM NOSE OF LO LEVEL JET...THAT WILL PROVIDE INTENSE LIFT THRU THE COLUMN ACROSS A WIDESPREAD AREA THIS EVENING. BUT ALREADY BY 06Z...MUCH OF THIS LIFT IS GONE IN AN INCREASINGLY DRY COLUMN SEVERELY LIMITING PCPN POTENTIAL LATE TONIGHT AND INTO SUNDAY MORNING. THE MAIN MODEL TRENDS FROM 24HRS AGO ARE A STRONGER WEDGE OF WARM AIR ALOFT...AND MORE PERSISTENT...AS WELL AS JUICIER MOISTURE TO WORK WITH FROM THE S-SE WHERE PWATS WILL PUSH TO 1.4" WHICH IS HIGHLY ANOMALOUS FOR MID JANUARY...OFTEN CLIMATOLOGICALLY THE COLDEST AND BY CONSEQUENCE THE DRIEST TIME OF THE YEAR. TAKE THE ABOVE AND COUPLE IT WITH THE FACT THAT THE MODELS SEEM TO BE UNDERESTIMATING THE STRENGTH OF THE COLD AIR AT THE SFC BEHIND CDFNT NOW PLOWING FROM KIRK-KJLN AT 09Z...COULD MAKE FOR A POTENTIALLY DANGEROUS WINTRY WX EVENT. BY THIS MEANING THAT THE ZONE OF MIXED WINTRY PCPN WILL PUSH FURTHER NWWD TOWARDS KUIN-KCOU AND IT IS LOOKING INCREASINGLY LIKELY THAT A ZONE OF FZRA WILL PUSH SEWD EDGING THE STL METRO AREA FROM THE NW AND EXTENDING SWWD ALG I-44 AND NEWD NEAR I-55. THE MOSTLY SNOW ZONE...ROUGHLY ALG-NW FROM A KUIN-KCOU LINE...IS EXPECTED TO RECEIVE 1-2"...WHILE AREAS FURTHER SE WILL RECEIVE A POTPOURRI OF WINTRY TYPES...FROM FZRA TO SLEET WITH SOME SNOW. LIGHT ICE AND SLEET/SNOW ACCUMS ARE EXPECTED BUT IT WILL NOT TAKE MUCH TO CREATE PROBLEMS. HAVE HOISTED A WINTER WX ADVISORY FOR THE WINTRY MIX AND SOMEWHAT HEAVIER SNOW ACCUMS ACROSS ABOUT THE NW HALF OF THE FA FOR THIS EVENING. PCPN MAY SNEAK IN SOONER...BUT DO NOT EXPECT ACCUMS AT THIS TIME BEFORE 00Z AND THINGS SHOULD TAPER DOWN SIGNIFICANTLY AFTER 06Z. ALSO ADDED THUNDER AND HEAVY RAINFALL MENTION FOR AREAS SE OF STL METRO BUT HELD OFF ON FFA FOR NOW WITH EXISTING DROUGHT AND LESS THAN 2" OF RAINFALL EXPECTED. WILL LET DAY CREW TAKE A FINAL LOOK ON THIS ITEM. (MONDAY - TUESDAY) COLD...BUT DRY...WX WILL PREVAIL FOR THIS PERIOD. ON TUESDAY...AN UPPER LEVEL SHORTWAVE WILL SLIDE THRU AS THE BASE OF THE LONGWAVE TROF MIGRATES E...BUT LIMITED MOISTURE TO WORK WITH TO LEAVE DRY FOR NOW. (WEDNESDAY - FRIDAY) LONGWAVE UPPER TROF SLIDES TO THE ERN CONUS BUT DE-AMPLIFIES IN THE PROCESS AND SO WILL GIVE TEMPS A CHANCE TO MODERATE A BIT. STILL LOOKS DRY AT THIS TIME...WITH SOME MODEL SPREADS SUGGESTING LIGHT PCPN POTENTIAL FOR THURSDAY...BUT NOT ENOUGH TO INCLUDE IN FCST AT THIS TIME. TES && .AVIATION... ISSUED AT 1151 AM CST SAT JAN 12 2013 DIFFICULT FORECAST DUE TO POTENTIAL FOR MIXED PRECIP THIS EVENING. COLD FRONT IS MOVING THROUGH THE AREA AT THIS TIME...HOWEVER THE COLD AIR IS VERY SHALLOW. CURRENT THINKING PRECIP SHOULD BE MOSTLY SLEET AND/OR SNOW ACROSS CENTRAL AND NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS...TRANSITIONING TO RAIN AND FREEZING RAIN WITH SOME SLEET IN EASTERN MISSOURI AND SOUTHWEST ILLINOIS...WITH MOSTLY RAIN IN SOUTHEAST MISSOURI AND SOUTH CENTRAL ILLINOIS UNTIL BETWEEN 10Z-12Z SUNDAY. SOME LINGERING LIGHT WINTRY PRECIPITATION IS LIKELY AFTER 12Z SUNDAY MORNING...MAINLY SOUTHEAST OF THE I-44 CORRIDOR IN MISSOURI AND THE I-70 CORRIDOR IN ILLINOIS. LOW MVFR AND IFR FLIGHT CONDITIONS WILL PREVAIL ONCE THE PRECIP STARTS AND WILL LIKELY CONTINUE THROUGH MUCH OF THE DAY SUNDAY. SPECIFICS FOR KSTL... COLD FRONT IS SOUTH OF LAMBERT AT THIS TIME. NORTHWEST WIND AND VFR WILL PREVAIL THROUGH MUCH OF THE AFTERNOON...BUT WILL SEE RAIN MOVE INTO THE TERMINAL FROM THE SOUTH. INITIAL SURGE OF RAIN SHOULD BE PRETTY LIGHT...BUT WILL SEE RAINFALL INTENSIFY WITH FLIGHT CONDITIONS DROPPING TO IFR BETWEEN 00Z AND 02Z. EXPECTING ALL LIQUID PRECIP TO CONTINUE UNTIL LATE EVENING WHEN TEMPERATURE SHOULD DROP TO FREEZING. PREDOMINANT PRECIP TYPE LOOKS TO BE FREEZING RAIN AFTER THIS. MAY SEE A LITTLE SLEET OR LIGHT SNOW MIXED IN BEFORE THE PRECIPITATION ENDS BETWEEN 08Z AND 10Z. LOW MVFR/IFR FLIGHT CONDITIONS WILL CONTINUE TO PREVAIL IN LIGHT FREEZING DRIZZLE OR FOG INTO THE DAYLIGHT HOURS OF SUNDAY BEFORE ENDING BY EARLY TO MID MORNING. CARNEY && .LSX WATCHES/WARNINGS/ADVISORIES... MO...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST TONIGHT FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO- CRAWFORD MO-FRANKLIN MO-GASCONADE MO-KNOX MO-LEWIS MO- LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO- OSAGE MO-PIKE MO-RALLS MO-SHELBY MO-ST. CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO. IL...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST TONIGHT FOR ADAMS IL-BROWN IL-CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-PIKE IL. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1205 AM CST SAT JAN 12 2013 ...UPDATED AVIATION DISCUSSION... .UPDATE... /834 PM CST Fri Jan 11 2013/ Looking at the latest model runs for tomorrow`s potential snowfall...some of the higher resolution models are hinting at a potential band of snow that could develop further west of the main area of precipitation, from east central KS into north central MO, possibly including parts of the KC metro. Earlier SREF members, specifically the ARW members, were the first to pick up on this possibility and now the 00Z NAM and even RAP are picking up on this as well. Frontogenesis progs and cross section analysis do indicate the potential for locally banded snowfall developing somewhere over eastern KS and western MO in the vicinity of a stalled 700-hPa boundary. This would be highly sensitive to small-scale fluctuations in the height field so it is not necessarily going to come to fruition. However, a small potential is there for a narrow band of 1"-3" across this corridor, possibly as high as 4" in a few spots given the banded nature. With the very high uncertainty, will not make any changes to the ongoing forecast and will let the overnight shift analyze the full suite of 00Z models before making the final call on this potential snow band. But for now, wanted to raise awareness that *if* the trend of the NAM, RAP and SREF were to continue, then our current snowfall forecast for the KC area could be too low. Hawblitzel && .DISCUSSION... The main focus for the next three days centers on the potential for accumulating snowfall Saturday night: Tonight - Saturday: The strong cold front that will be tracking through the forecast area tonight through Saturday was situated from northeastern Nebraska through northwestern Kansas. This front is expected to start entering northwestern Missouri around midnight tonight and then be through the forecast area by mid morning. The night will start rather mild with decent mixing ahead of the front keeping temperatures ahead of the front in the upper 40s and 50s. Temperatures will fall into the 20s and 30s behind the front with temperatures nearly steady during the day Saturday. In fact, we will likely see our highs early in the day before the cold advection overwhelms things. Highs on Saturday should range from the upper 20s in far northwestern Missouri to the lower 40s in parts of central Missouri. Saturday night: As the strong cold advection is occurring, a weak system will move northwest out of the Southern Plains and track across Arkansas and southern Missouri. This system will interact with a strong jet stream moving across the region and for part of the night much of the forecast area will be the right rear quadrant of the upper jet. This will enable broad frontogenetic forcing leading to a brief period of strong upward lift. This will lead to several hours of snowfall across areas mainly east of Interstate 35. The heaviest accumulations of snow should be over portions of central Missouri where as much as 2 inches looks possible given the available moisture, the intensity of the system and the short duration of the event itself. Further west, across east central Kansas, west central Missouri and northwestern Missouri accumulations will be less than an inch with little or no accumulation expected across far northwestern Missouri and extreme northeastern Kansas. Sunday: This system will be quick-hitting and is expected to be out of the region by late Sunday morning. As the system exits, skies should clear out but temperatures will continue to be cold with highs in the 20s and 30s. CDB Medium Range (Monday through Friday)... Through the medium range, the pattern will gradually transition from deep troughing over the Plains and eastern Rockies to warmer, more zonal flow throughout the CONUS. Temperatures on Monday and Tuesday continue to look colder than average with chilly Canadian air continuing to flow into the region, then will gradually rise to near or just above normal for Wednesday through at least Thursday. There is some degree of disagreement among the longer-range models on the extent and progression of arctic air into the CONUS by the end of the work week as a broad, deep trough edges across the Canadian border, which could strongly impact the temperature forecast. If the 12z ECMWF verifies going into the weekend, very cold temperatures could slide into the CWA, despite a current consensus of slightly above normal temperatures for that period. Thus, this will be something to monitor for significant changes as this time period draws closer. No precipitation is expected through this period, as surface high pressure becomes semi-permanent across the central and southern Plains and the split jet structure keeps systems confined to far northern and southeastern portions of the country. Laflin && .AVIATION... For the 06Z TAFs...cold front will move through the terminals within the first couple hours of the forecast with winds veering from wsw to nw. Pressure gradient remains tight both ahead and immediately behind the front such that gusty winds expected for at least a few hours after fropa. Satellite cloud trends and upstream ceilings are not as pessimistic so will allow for generally VFR conditions although a few hours of MVFR are expected at KSTJ. Latest short range models now keying in on the increasing potential for banded snow a bit further northwest...spreading from east central KS through west central MO, including the KMCI/KMKC terminals, shortly after sunset. Model fields suggest a setup favoring banded snow which would result in a period of several hours of moderate snow intensity and MVFR/IFR conditions. Since the snow bands will likely be very narrow the heaviest bands could easily set up and miss the terminals. However, feel the threat is such that a PROB group was used to highlight the potential. MJ && .EAX WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
155 AM CST SAT JAN 12 2013 .DISCUSSION...UPDATED THE FORECAST TO END THE WIND ADVISORY AND TO LOWER LOW TEMPERATURES TONIGHT. && .PREV DISCUSSION... /ISSUED 1119 PM CST FRI JAN 11 2013/ AVIATION...06Z KGRI TAF. DRIER LOW TO MID LEVEL AIR IS HELPING RESTORE VFR CONDITIONS AT THE TERMINAL AND ALTHOUGH TEMPORARY MVFR CEILINGS CANNOT BE RULED OUT THROUGH 08Z...PREVAILING VFR CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS. THE SURFACE WIND WILL REMAIN STRONG FROM THE NORTHWEST...SUSTAINED AT AROUND 25KTS AND GUSTING NEAR 30KTS...TO START THE TAF PERIOD...BUT DECREASE IN INTENSITY THEREAFTER. VISIBILITY RESTRICTION IS NOT EXPECTED THROUGH THE NEXT 24 HOURS. PREV DISCUSSION... /ISSUED 843 PM CST FRI JAN 11 2013/ UPDATE...FOG AND LIGHT FREEZING RAIN WHICH WERE OBSERVED AT VARIOUS POINTS ACROSS THE CWA EARLIER THIS EVENING HAVE SINCE DISSIPATED. WENT AHEAD AND REMOVED ANY SUCH WORDING FROM THE GRIDS AND HWO. ANY REPORTS OF BLOWING DUST FROM ACROSS OUR KANSAS COUNTIES HAVE ALSO CEASED SO WENT AHEAD AND REMOVED SUCH WORDING FROM THE FORECAST. AS OF 02Z THE LOW LEVEL BAROCLINIC ZONE WAS LOCATED FROM NEAR KLNK...TO NEAR KHJH...TO NEAR KK61. THE SURFACE WIND HAS TRANSITIONED TO THE NORTHWEST FOR MOST LOCATIONS ACROSS OUR CWA AS A RESULT. LOW LEVEL PRESSURE RISES POST-FROPA ARE INDUCING AN INCREASING LOW LEVEL PRESSURE GRADIENT ACROSS MUCH OF THE CWA AT THIS HOUR...WITH THE STRONGEST PRESSURE RISES BEING OBSERVED THROUGH THE TRI-CITIES AREA. A THIN CORRIDOR OF SUSTAINED WIND NEAR 25KTS IS BEING OBSERVED FROM KAUH...TO KHSI...TO KGRI...AND SOUTH TO KK82...WITH A SUSTAINED WIND CLOSER TO THE 15-20KT RANGE AT LOCATIONS FARTHER EAST AND WEST. SHORT TERM GUIDANCE FROM THE RAP SUGGESTS THE LOW LEVEL PRESSURE RISES SHOULD DIMINISH ACROSS MUCH OF OUR AREA HEADING INTO THE OVERNIGHT HOURS AND WITH A RESULTANT DECREASE IN THE LOW LEVEL PRESSURE GRADIENT...THE LOW LEVEL WIND FIELD SHOULD ALSO DIMINISH IN INTENSITY. THIS IS A SOLUTION ALSO SUPPORTED BY THE NAM AND OPERATIONAL GFS. THE ONLY EXCEPTION MAY BE ACROSS OUR FAR NORTH/NORTHEASTERN CWA WHERE THE INCREASED LOW LEVEL PRESSURE GRADIENT MAY REMAIN INTACT FOR A FEW HOURS LONGER...THUS ALLOWING FOR A SOMEWHAT STRONGER WIND HEADING INTO THE EARLY MORNING HOURS SATURDAY. GIVEN ALL THIS...WENT AHEAD AND CANCELLED THE WIND ADVISORY WHICH WAS IN EFFECT FOR SOME OF OUR KANSAS COUNTIES. ALSO WENT AHEAD AND PUSHED THE WIND ADVISORY...IN EFFECT FOR OUR NEBRASKA COUNTIES...NORTH OF I-80 WHERE THE STRONGER LOW LEVEL PRESSURE GRADIENT IS EXPECTED TO LINGER LONGER. THIS IS A DECISION WHICH SEEMS A BIT SHAKY RIGHT NOW GIVEN THAT THE TRI-CITIES HAVE SEEN A DRASTIC INCREASE IN WIND SPEED IN THE LAST HOUR BUT AGAIN...THE CURRENT BELIEF IS THAT THE WIND WILL DIMINISH WITHIN ANOTHER HOUR ACROSS THE TRI-CITIES..LEAVING ONLY OUR FAR NORTH/NORTHEAST AT AN INCREASED RISK OF OBSERVING A WIND WHICH MEETS WIND ADVISORY CRITERIA. ALSO WENT AHEAD AND TWEAKED HOURLY TEMPERATURE...DEWPOINT AND SKY GRIDS TO BETTER REFLECT CURRENT TRENDS. PREV DISCUSSION... /ISSUED 621 PM CST FRI JAN 11 2013/ UPDATE...EVENING UPPER AIR ANALYSIS PER RAP ANALYSIS DATA INDICATES LONGWAVE TROUGHING OVER THE WESTERN HALF OF THE CONUS...WITH RIDGING OVER THE EAST. MID AND UPPER LEVEL JET ENERGY EXTENDS FROM THE FOUR CORNERS REGION...NORTHEAST ACROSS THE CENTRAL PLAINS...AND THEN FARTHER NORTHEAST INTO SOUTHERN AND SOUTHEASTERN CANADA. MID AND UPPER TROPOSPHERIC FLOW IS QUITE STRONG OVER OUR AREA AS A RESULT...MAXING OUT AT AROUND 150KTS PER 23Z RAP ANALYSIS SOUNDING DATA FROM KGRI. ITS WORTH NOTING THAT THE LOWER TROPOSPHERE IS ALSO EXHIBITING VERY STRONG FLOW...50-55KTS ALL THE WAY TO THE TOP OF THE LOW LEVEL INVERSION NEAR 800MB. WATER VAPOR IMAGERY INDICATES A CLOSED MID LEVEL LOW OVER WESTERN WYOMING. A MID LEVEL SHORT WAVE IS ALSO NOTED OVER THE CENTRAL HIGH PLAINS...ADVANCING NORTHEAST ACROSS THE REGION ALONG THE EASTERN PERIPHERY OF THE CLOSED MID LEVEL LOW. WATER VAPOR IMAGERY ALSO INDICATES INCREASED VALUES OF MID LEVEL MOISTURE EXTENDING FROM WEST-TEXAS...NORTHEAST INTO THE CENTRAL PLAINS AND MID TO UPPER MISSISSIPPI VALLEY. A MID LEVEL DRY INTRUSION IS ALSO NOTED EXTENDING FROM THE FOUR CORNERS REGION NORTHEAST INTO THE CENTRAL HIGH PLAINS. AT THE SURFACE A ~992MB LOW IS NOTED BETWEEN KMCK AND KHLC...WITH AN ASSOCIATED FRONTAL BOUNDARY EXTENDING EAST/NORTHEAST FROM THE LOW ACROSS CENTRAL AND NORTHEASTERN NEBRASKA...AND A COLD FRONT EXTENDING WEST/SOUTHWEST FROM THE LOW INTO NORTHWESTERN KANSAS AND SOUTHEASTERN COLORADO. A DRY LINE IS ALSO NOTED EXTENDING SOUTH FROM THE LOW ACROSS WESTERN KANSAS. BLOWING DUST REMAINED EVIDENT ON VISIBLE SATELLITE IMAGERY UNTIL SUNSET THIS EVENING BUT AT THIS TIME HAVE NO REASON TO BELIEVE IT HAS SUBSIDED AS GUSTY WINDS AND MINOR VISIBILITY RESTRICTIONS ARE STILL BEING REPORTED FROM KPHG TO KHLC. THAT BEING SAID...GIVEN THE LINGERING SNOWPACK AND WET GROUNDS ACROSS OUR AREA IT APPEARS UNLIKELY VISIBILITY RESTRICTIONS WILL WORSEN THROUGH THE NEXT COUPLE OF HOURS...AND WITH VISIBILITY GREATER THAN 1 1/2SM AT KPHG...AM COMFORTABLE WITH THE BLOWING DUST MENTION IN THE CURRENT WIND ADVISORY AND HWO. NO PLANS FOR A FORMAL BLOWING DUST ADVISORY AT THIS TIME. A THIN CORRIDOR OF DENSE FOG HAS DEVELOPED ALONG THE LOW LEVEL BAROCLINIC ZONE CURRENTLY PUSHING ACROSS THE CWA. KHSI DROPPED TO 1/4SM FOR A BRIEF TIME THIS AFTERNOON...WITH LOCATIONS FROM KAUH TO OSCEOLA AND KJYR ALSO REPORTING SIGNIFICANT VISIBILITY RESTRICTIONS IN FOG THROUGH THE PAST COUPLE OF HOURS. WHAT FOG IS REALIZED DOES NOT LAST LONG AS IT CONTINUES TO MOVE EAST...BUT WENT AHEAD AND INSERTED PATCHY DENSE FOG IN THE GRIDS THROUGH 01Z TO ACCOUNT FOR ONGOING ACTIVITY. MID LEVEL THERMAL ADVECTION AND MODEST DPVA AHEAD OF THE MID LEVEL SHORT WAVE OVER THE CENTRAL HIGH PLAINS IS PROMOTING WIDESPREAD PRECIPITATION OVER WESTERN NEBRASKA...WITH SOME OF THIS PRECIPITATION MANAGING TO CLIP FAR WEST/NORTHWESTERN PORTIONS OF OUR CWA IN THE LAST HOUR. PROXIMITY SOUNDINGS FROM OUR WEST/NORTHWEST CWA PER RAP ANALYSIS DATA SUGGESTS AN ELEVATED WARM LAYER EXISTS BETWEEN 850 AND 800MB...AND PERIODIC LIGHT FREEZING RAIN WAS REPORTED IN DAWSON COUNTY IN THE LAST HOUR. GIVEN THE CURRENT RETURNS FROM KUEX...ANY FREEZING RAIN THAT IS REALIZED SHOULD REMAIN VERY LIGHT AND SHOULD NOT PRODUCE MUCH IN THE WAY OF ICE ACCUMULATION. THAT BEING SAID...FELT MORE COMFORTABLE INTRODUCING LIGHT FREEZING RAIN WORDING TO THE GRIDS AND HWO...THROUGH 01Z...FOR OUR FAR WEST/NORTHWEST CWA. WIND ADVISORIES ACROSS OUR AREA REMAIN INTACT WITH NO CHANGES MADE AT THIS TIME. THOSE HEADLINES WILL BE EVALUATED AND POTENTIALLY ADJUSTED LATER THIS EVENING. REMAINDER OF THE FORECAST REMAINS IN GOOD SHAPE...WITH ONLY MINOR TWEAKS MADE TO HOURLY TEMPERATURE...WIND...AND DEWPOINT GRIDS TO BETTER REFLECT REALITY. PREV DISCUSSION... /ISSUED 405 PM CST FRI JAN 11 2013/ SHORT TERM...NOW THROUGH SATURDAY WINTERS COLD RETURNS TO THE CNTRL PLAINS TONIGHT WITH A PERIOD OF STRONG WIND GUSTS IN THE TRANSITION... AN SPS WAS ISSUED AT 2032Z FOR THE BLOWING DUST AND WILL PROBABLY BE UPDATED BY THE BOTTOM OF THE HOUR. WIND ADVISORIES CONTINUE AS POSTED. NPW WAS UPDATED/SENT AT 324 PM TO RAISE ADDITIONAL AWARENESS OF BLOWING DUST OVER KS. NOW: STRONG COLD FRONT IS SAGGING SE THRU CNTRL NEB. IT WAS LAST SEEN ON THE LNX 88D AT 1825Z JUST NW OF BBW. THE TIMING TOOL BRINGS IT INTO GRI BY 2230Z. 992 MB LOW WAS TRACKING ALONG THE KS-NEB BORDER...S OF WHERE IT WAS FCST 24 HRS AGO. THE FRONT IS AHEAD OF SCHEDULE SO USED THE RAP FOR SHORT-TERM WINDS. THE 18Z RAP SUGGESTS IT FINALLY CUTS NE THIS EVNG ACROSS ERN NEB. BLOWING DUST: A BURST OF 33-41 KT WINDS HAS RESULTED IN A LARGE AREA OF BLOWING DUST THAT ORIGINATED OVER ERN CO. TIMING TOOL WILL BRING THIS INTO OUR KS COUNTIES AROUND 445 PM AND IT WILL CONTINUE UNTIL WIND SHIFT ASSOCIATED WITH COLD FRONTAL PASSAGE. CONTEMPLATED CANCELLING THE WIND ADVISORY FOR N-CNTRL KS SINCE WINDS HAVE BEEN WELL BELOW ADVISORY SUSTAINED OR GUSTS. BUT GIVEN MULTIPLE G40 KTS WITH THAT DUST...HAVE CONTINUED ADVISORY. A LARGE AREA OF STRATUS IS EXPECTED TO SINK S BEHIND THE FRONT TNGT IN THE WAKE OF THE DEPARTING LOW. HOW FAR S OVC EXTENDS REMAINS UNCERTAIN GIVEN DOWNSLOPING WINDS WILL TEND TO BREAK IT UP. WIND: 3 HR PRES RISES ARE ONLY 3 MB OVER THE NEB PANHANDLE AT 21Z. THE NAM IS OVER ESTIMATING THIS BY 5 MB AND THE RAP BY 3 MB. THINK THE TREND IS RIGHT WITH EXPANDING/INCREASING PRES RISES AS THE LOW ACCELERATES NEWD THIS EVE...BUT THE MAGNITUDE MAY BE OVERDONE. CONFIDENCE IS ABOVE AVERAGE FOR VERIFYING THE ADVISORY OVER N-CNTRL KS AHEAD OF THE FRONT. IT/S TAKEN ALL DAY BUT IT WILL VERIFY 22Z-03Z. BEHIND THE FRONT HAVE YET TO SEE ADVISORY LEVEL WINDS DEVELOP. LOW-LEVELS WILL BECOME UNSTABLE IN CAA THIS EVE AND BUT THIS APPEARS A MARGINAL WIND EVENT SO VERIFYING NEB WIND ADVISORY IS BELOW AVERAGE ALONG AND S OF I-80. BEST CHANCE FOR A ONE-TIME 45 MPH GUST WILL BE N OF THE TRI-CITIES. THE BEST CHANCE FOR VERIFYING ALONG AND S OF I-80 WILL PROBABLY BE A BRIEF PERIOD OF SUSTAINED WINDS OF 30 MPH. TNGT: M/CLOUDY WITH BLUSTERY NW WINDS. SOME FLURRIES OR BRIEF SHSN WILL OCCUR 6PM-12AM IN PULSE OF CAA. TEMP GUIDANCE WAS IN GOOD AGREEMENT AND USED THE CONSENSUS OF ALL GUIDANCE WHICH BASICALLY PUTS TEMPS NEAR NORMAL. SAT: A MIX OF CLOUDS/SUN. UNSURE HOW MUCH STRATOCU GETS TRAPPED UNDER FRONTAL INVERSION. HAVE ALREADY INCREASED CLOUDS ABOVE PREVIOUS GID FCST AND IF NAM BUFKIT IS RIGHT THAN WE WILL BE TOO LOW ON CLOUD COVER. REGARDLESS...PATCHES JET STREAM CIRRUS WILL KEEP THE SKY AT LEAST P/CLOUDY. STILL A BLUSTERY NW WIND WITH GUST UP TO 30 MPH FORENOON. TEMPS ARE NAM 2M TEMPS WHICH IS CLOSE TO THE PREVIOUS FCST...ABOUT 12F BELOW NORMAL. LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. THIS WILL LIKELY BE A DRY PERIOD WITH TEMPERATURES GENERALLY WARMING THROUGH AT LEAST WEDNESDAY. MORE UNCERTAINTY ENTERS THE PICTURE BY THURSDAY AND FRIDAY. SATURDAY NIGHT THROUGH MONDAY...A COLD AREA OF ARCTIC HIGH PRESSURE WILL BEGIN TO SLIDE INTO THE PLAINS SATURDAY NIGHT INTO SUNDAY AND REMAIN THROUGH AT LEAST MONDAY. THERE WILL BE A LARGE UPPER TROUGH SITUATED OVER THE PLAINS BUT ALL OF THE MOISTURE WILL BE AT THE LEADING EDGE OF THIS TROUGH AND WELL OFF TO OUR EAST. HIGH TEMPERATURES WILL BE STUCK IN THE 20S ON SUNDAY AND POSSIBLY MONDAY AS WELL. SOME AREAS THAT ARE COMPLETELY FREE OF SNOW COVER MAY REACH THE LOWER 30S ON MONDAY. TUESDAY AND WEDNESDAY...THE 12Z ECMWF PUSHES THE SFC HIGH OFF TO OUR SOUTH ALLOWING FOR WEST SOUTHWEST DOWNSLOPE SFC WINDS. THE SHALLOW COLD AIR WILL GRADUALLY MODERATE WITH HIGH TEMPERATURES BACK INTO THE 30S ON TUESDAY AND PROBABLY 40S BY WEDNESDAY. THURSDAY THROUGH FRIDAY...THERE IS A SUBSTANTIAL AMOUNT OF MODEL UNCERTAINTY WITH REGARD TO TEMPERATURES. HOWEVER...THERE IS GOOD MODEL AGREEMENT IN DRY CONDITIONS. THE ECMWF BRINGS A COLD FRONT THROUGH WEDNESDAY NIGHT WITH STRONG COLD AIR ADVECTION ON THURSDAY. THE 850 MB TEMPERATURES THURSDAY EVENING RANGE FROM -15C ON THE 12Z ECMWF TO 5C ON THE 12Z GFS FOR A SIGNIFICANT 20C DEGREE SPREAD. THE OFFICIAL FORECAST IS SOMEWHERE IN THE MIDDLE OF THESE TWO MODELS CALLING FOR ABOVE FREEZING HIGHS IN THE UPPER 30S TO LOWER 40S. HOWEVER...THESE HIGHS MAY VERY WELL BE TOO WARM. THE ONGOING STRATOSPHERIC WARMING EVENT WILL LIKELY RESULT IN THE TRANSITION TO A NEGATIVE ARCTIC OSCILLATION PATTERN...WHICH TENDS TO BRING THE COLD AIR DOWN OUT OF CANADA INTO THE EASTERN TWO THIRDS OF THE CONUS. THEREFORE...I WOULD LEAN MORE TOWARDS THE ECWMF AND THE POSSIBILITY OF COLDER TEMPERATURES THAN WHAT WE ARE OFFICIALLY CALLING FOR AS THIS BETTER FITS THE -AO PATTERN. IF THE 12Z ECMWF COLDER TREND CONTINUES...WE WILL NEED TO BE LOWERING OUR THURSDAY AND FRIDAY HIGH TEMPERATURES. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ DISCUSSION (UPDATE)...HEINLEIN AVIATION/EARLIER UPDATES...BRYANT SHORT TERM...HALBLAUB LONG TERM...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1119 PM CST FRI JAN 11 2013 .AVIATION...06Z KGRI TAF. DRIER LOW TO MID LEVEL AIR IS HELPING RESTORE VFR CONDITIONS AT THE TERMINAL AND ALTHOUGH TEMPORARY MVFR CEILINGS CANNOT BE RULED OUT THROUGH 08Z...PREVAILING VFR CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS. THE SURFACE WIND WILL REMAIN STRONG FROM THE NORTHWEST...SUSTAINED AT AROUND 25KTS AND GUSTING NEAR 30KTS...TO START THE TAF PERIOD...BUT DECREASE IN INTENSITY THEREAFTER. VISIBILITY RESTRICTION IS NOT EXPECTED THROUGH THE NEXT 24 HOURS. && .PREV DISCUSSION... /ISSUED 843 PM CST FRI JAN 11 2013/ UPDATE...FOG AND LIGHT FREEZING RAIN WHICH WERE OBSERVED AT VARIOUS POINTS ACROSS THE CWA EARLIER THIS EVENING HAVE SINCE DISSIPATED. WENT AHEAD AND REMOVED ANY SUCH WORDING FROM THE GRIDS AND HWO. ANY REPORTS OF BLOWING DUST FROM ACROSS OUR KANSAS COUNTIES HAVE ALSO CEASED SO WENT AHEAD AND REMOVED SUCH WORDING FROM THE FORECAST. AS OF 02Z THE LOW LEVEL BAROCLINIC ZONE WAS LOCATED FROM NEAR KLNK...TO NEAR KHJH...TO NEAR KK61. THE SURFACE WIND HAS TRANSITIONED TO THE NORTHWEST FOR MOST LOCATIONS ACROSS OUR CWA AS A RESULT. LOW LEVEL PRESSURE RISES POST-FROPA ARE INDUCING AN INCREASING LOW LEVEL PRESSURE GRADIENT ACROSS MUCH OF THE CWA AT THIS HOUR...WITH THE STRONGEST PRESSURE RISES BEING OBSERVED THROUGH THE TRI-CITIES AREA. A THIN CORRIDOR OF SUSTAINED WIND NEAR 25KTS IS BEING OBSERVED FROM KAUH...TO KHSI...TO KGRI...AND SOUTH TO KK82...WITH A SUSTAINED WIND CLOSER TO THE 15-20KT RANGE AT LOCATIONS FARTHER EAST AND WEST. SHORT TERM GUIDANCE FROM THE RAP SUGGESTS THE LOW LEVEL PRESSURE RISES SHOULD DIMINISH ACROSS MUCH OF OUR AREA HEADING INTO THE OVERNIGHT HOURS AND WITH A RESULTANT DECREASE IN THE LOW LEVEL PRESSURE GRADIENT...THE LOW LEVEL WIND FIELD SHOULD ALSO DIMINISH IN INTENSITY. THIS IS A SOLUTION ALSO SUPPORTED BY THE NAM AND OPERATIONAL GFS. THE ONLY EXCEPTION MAY BE ACROSS OUR FAR NORTH/NORTHEASTERN CWA WHERE THE INCREASED LOW LEVEL PRESSURE GRADIENT MAY REMAIN INTACT FOR A FEW HOURS LONGER...THUS ALLOWING FOR A SOMEWHAT STRONGER WIND HEADING INTO THE EARLY MORNING HOURS SATURDAY. GIVEN ALL THIS...WENT AHEAD AND CANCELLED THE WIND ADVISORY WHICH WAS IN EFFECT FOR SOME OF OUR KANSAS COUNTIES. ALSO WENT AHEAD AND PUSHED THE WIND ADVISORY...IN EFFECT FOR OUR NEBRASKA COUNTIES...NORTH OF I-80 WHERE THE STRONGER LOW LEVEL PRESSURE GRADIENT IS EXPECTED TO LINGER LONGER. THIS IS A DECISION WHICH SEEMS A BIT SHAKY RIGHT NOW GIVEN THAT THE TRI-CITIES HAVE SEEN A DRASTIC INCREASE IN WIND SPEED IN THE LAST HOUR BUT AGAIN...THE CURRENT BELIEF IS THAT THE WIND WILL DIMINISH WITHIN ANOTHER HOUR ACROSS THE TRI-CITIES..LEAVING ONLY OUR FAR NORTH/NORTHEAST AT AN INCREASED RISK OF OBSERVING A WIND WHICH MEETS WIND ADVISORY CRITERIA. ALSO WENT AHEAD AND TWEAKED HOURLY TEMPERATURE...DEWPOINT AND SKY GRIDS TO BETTER REFLECT CURRENT TRENDS. PREV DISCUSSION... /ISSUED 621 PM CST FRI JAN 11 2013/ UPDATE...EVENING UPPER AIR ANALYSIS PER RAP ANALYSIS DATA INDICATES LONGWAVE TROUGHING OVER THE WESTERN HALF OF THE CONUS...WITH RIDGING OVER THE EAST. MID AND UPPER LEVEL JET ENERGY EXTENDS FROM THE FOUR CORNERS REGION...NORTHEAST ACROSS THE CENTRAL PLAINS...AND THEN FARTHER NORTHEAST INTO SOUTHERN AND SOUTHEASTERN CANADA. MID AND UPPER TROPOSPHERIC FLOW IS QUITE STRONG OVER OUR AREA AS A RESULT...MAXING OUT AT AROUND 150KTS PER 23Z RAP ANALYSIS SOUNDING DATA FROM KGRI. ITS WORTH NOTING THAT THE LOWER TROPOSPHERE IS ALSO EXHIBITING VERY STRONG FLOW...50-55KTS ALL THE WAY TO THE TOP OF THE LOW LEVEL INVERSION NEAR 800MB. WATER VAPOR IMAGERY INDICATES A CLOSED MID LEVEL LOW OVER WESTERN WYOMING. A MID LEVEL SHORT WAVE IS ALSO NOTED OVER THE CENTRAL HIGH PLAINS...ADVANCING NORTHEAST ACROSS THE REGION ALONG THE EASTERN PERIPHERY OF THE CLOSED MID LEVEL LOW. WATER VAPOR IMAGERY ALSO INDICATES INCREASED VALUES OF MID LEVEL MOISTURE EXTENDING FROM WEST-TEXAS...NORTHEAST INTO THE CENTRAL PLAINS AND MID TO UPPER MISSISSIPPI VALLEY. A MID LEVEL DRY INTRUSION IS ALSO NOTED EXTENDING FROM THE FOUR CORNERS REGION NORTHEAST INTO THE CENTRAL HIGH PLAINS. AT THE SURFACE A ~992MB LOW IS NOTED BETWEEN KMCK AND KHLC...WITH AN ASSOCIATED FRONTAL BOUNDARY EXTENDING EAST/NORTHEAST FROM THE LOW ACROSS CENTRAL AND NORTHEASTERN NEBRASKA...AND A COLD FRONT EXTENDING WEST/SOUTHWEST FROM THE LOW INTO NORTHWESTERN KANSAS AND SOUTHEASTERN COLORADO. A DRY LINE IS ALSO NOTED EXTENDING SOUTH FROM THE LOW ACROSS WESTERN KANSAS. BLOWING DUST REMAINED EVIDENT ON VISIBLE SATELLITE IMAGERY UNTIL SUNSET THIS EVENING BUT AT THIS TIME HAVE NO REASON TO BELIEVE IT HAS SUBSIDED AS GUSTY WINDS AND MINOR VISIBILITY RESTRICTIONS ARE STILL BEING REPORTED FROM KPHG TO KHLC. THAT BEING SAID...GIVEN THE LINGERING SNOWPACK AND WET GROUNDS ACROSS OUR AREA IT APPEARS UNLIKELY VISIBILITY RESTRICTIONS WILL WORSEN THROUGH THE NEXT COUPLE OF HOURS...AND WITH VISIBILITY GREATER THAN 1 1/2SM AT KPHG...AM COMFORTABLE WITH THE BLOWING DUST MENTION IN THE CURRENT WIND ADVISORY AND HWO. NO PLANS FOR A FORMAL BLOWING DUST ADVISORY AT THIS TIME. A THIN CORRIDOR OF DENSE FOG HAS DEVELOPED ALONG THE LOW LEVEL BAROCLINIC ZONE CURRENTLY PUSHING ACROSS THE CWA. KHSI DROPPED TO 1/4SM FOR A BRIEF TIME THIS AFTERNOON...WITH LOCATIONS FROM KAUH TO OSCEOLA AND KJYR ALSO REPORTING SIGNIFICANT VISIBILITY RESTRICTIONS IN FOG THROUGH THE PAST COUPLE OF HOURS. WHAT FOG IS REALIZED DOES NOT LAST LONG AS IT CONTINUES TO MOVE EAST...BUT WENT AHEAD AND INSERTED PATCHY DENSE FOG IN THE GRIDS THROUGH 01Z TO ACCOUNT FOR ONGOING ACTIVITY. MID LEVEL THERMAL ADVECTION AND MODEST DPVA AHEAD OF THE MID LEVEL SHORT WAVE OVER THE CENTRAL HIGH PLAINS IS PROMOTING WIDESPREAD PRECIPITATION OVER WESTERN NEBRASKA...WITH SOME OF THIS PRECIPITATION MANAGING TO CLIP FAR WEST/NORTHWESTERN PORTIONS OF OUR CWA IN THE LAST HOUR. PROXIMITY SOUNDINGS FROM OUR WEST/NORTHWEST CWA PER RAP ANALYSIS DATA SUGGESTS AN ELEVATED WARM LAYER EXISTS BETWEEN 850 AND 800MB...AND PERIODIC LIGHT FREEZING RAIN WAS REPORTED IN DAWSON COUNTY IN THE LAST HOUR. GIVEN THE CURRENT RETURNS FROM KUEX...ANY FREEZING RAIN THAT IS REALIZED SHOULD REMAIN VERY LIGHT AND SHOULD NOT PRODUCE MUCH IN THE WAY OF ICE ACCUMULATION. THAT BEING SAID...FELT MORE COMFORTABLE INTRODUCING LIGHT FREEZING RAIN WORDING TO THE GRIDS AND HWO...THROUGH 01Z...FOR OUR FAR WEST/NORTHWEST CWA. WIND ADVISORIES ACROSS OUR AREA REMAIN INTACT WITH NO CHANGES MADE AT THIS TIME. THOSE HEADLINES WILL BE EVALUATED AND POTENTIALLY ADJUSTED LATER THIS EVENING. REMAINDER OF THE FORECAST REMAINS IN GOOD SHAPE...WITH ONLY MINOR TWEAKS MADE TO HOURLY TEMPERATURE...WIND...AND DEWPOINT GRIDS TO BETTER REFLECT REALITY. PREV DISCUSSION... /ISSUED 405 PM CST FRI JAN 11 2013/ SHORT TERM...NOW THROUGH SATURDAY WINTERS COLD RETURNS TO THE CNTRL PLAINS TONIGHT WITH A PERIOD OF STRONG WIND GUSTS IN THE TRANSITION... AN SPS WAS ISSUED AT 2032Z FOR THE BLOWING DUST AND WILL PROBABLY BE UPDATED BY THE BOTTOM OF THE HOUR. WIND ADVISORIES CONTINUE AS POSTED. NPW WAS UPDATED/SENT AT 324 PM TO RAISE ADDITIONAL AWARENESS OF BLOWING DUST OVER KS. NOW: STRONG COLD FRONT IS SAGGING SE THRU CNTRL NEB. IT WAS LAST SEEN ON THE LNX 88D AT 1825Z JUST NW OF BBW. THE TIMING TOOL BRINGS IT INTO GRI BY 2230Z. 992 MB LOW WAS TRACKING ALONG THE KS-NEB BORDER...S OF WHERE IT WAS FCST 24 HRS AGO. THE FRONT IS AHEAD OF SCHEDULE SO USED THE RAP FOR SHORT-TERM WINDS. THE 18Z RAP SUGGESTS IT FINALLY CUTS NE THIS EVNG ACROSS ERN NEB. BLOWING DUST: A BURST OF 33-41 KT WINDS HAS RESULTED IN A LARGE AREA OF BLOWING DUST THAT ORIGINATED OVER ERN CO. TIMING TOOL WILL BRING THIS INTO OUR KS COUNTIES AROUND 445 PM AND IT WILL CONTINUE UNTIL WIND SHIFT ASSOCIATED WITH COLD FRONTAL PASSAGE. CONTEMPLATED CANCELLING THE WIND ADVISORY FOR N-CNTRL KS SINCE WINDS HAVE BEEN WELL BELOW ADVISORY SUSTAINED OR GUSTS. BUT GIVEN MULTIPLE G40 KTS WITH THAT DUST...HAVE CONTINUED ADVISORY. A LARGE AREA OF STRATUS IS EXPECTED TO SINK S BEHIND THE FRONT TNGT IN THE WAKE OF THE DEPARTING LOW. HOW FAR S OVC EXTENDS REMAINS UNCERTAIN GIVEN DOWNSLOPING WINDS WILL TEND TO BREAK IT UP. WIND: 3 HR PRES RISES ARE ONLY 3 MB OVER THE NEB PANHANDLE AT 21Z. THE NAM IS OVER ESTIMATING THIS BY 5 MB AND THE RAP BY 3 MB. THINK THE TREND IS RIGHT WITH EXPANDING/INCREASING PRES RISES AS THE LOW ACCELERATES NEWD THIS EVE...BUT THE MAGNITUDE MAY BE OVERDONE. CONFIDENCE IS ABOVE AVERAGE FOR VERIFYING THE ADVISORY OVER N-CNTRL KS AHEAD OF THE FRONT. IT/S TAKEN ALL DAY BUT IT WILL VERIFY 22Z-03Z. BEHIND THE FRONT HAVE YET TO SEE ADVISORY LEVEL WINDS DEVELOP. LOW-LEVELS WILL BECOME UNSTABLE IN CAA THIS EVE AND BUT THIS APPEARS A MARGINAL WIND EVENT SO VERIFYING NEB WIND ADVISORY IS BELOW AVERAGE ALONG AND S OF I-80. BEST CHANCE FOR A ONE-TIME 45 MPH GUST WILL BE N OF THE TRI-CITIES. THE BEST CHANCE FOR VERIFYING ALONG AND S OF I-80 WILL PROBABLY BE A BRIEF PERIOD OF SUSTAINED WINDS OF 30 MPH. TNGT: M/CLOUDY WITH BLUSTERY NW WINDS. SOME FLURRIES OR BRIEF SHSN WILL OCCUR 6PM-12AM IN PULSE OF CAA. TEMP GUIDANCE WAS IN GOOD AGREEMENT AND USED THE CONSENSUS OF ALL GUIDANCE WHICH BASICALLY PUTS TEMPS NEAR NORMAL. SAT: A MIX OF CLOUDS/SUN. UNSURE HOW MUCH STRATOCU GETS TRAPPED UNDER FRONTAL INVERSION. HAVE ALREADY INCREASED CLOUDS ABOVE PREVIOUS GID FCST AND IF NAM BUFKIT IS RIGHT THAN WE WILL BE TOO LOW ON CLOUD COVER. REGARDLESS...PATCHES JET STREAM CIRRUS WILL KEEP THE SKY AT LEAST P/CLOUDY. STILL A BLUSTERY NW WIND WITH GUST UP TO 30 MPH FORENOON. TEMPS ARE NAM 2M TEMPS WHICH IS CLOSE TO THE PREVIOUS FCST...ABOUT 12F BELOW NORMAL. LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. THIS WILL LIKELY BE A DRY PERIOD WITH TEMPERATURES GENERALLY WARMING THROUGH AT LEAST WEDNESDAY. MORE UNCERTAINTY ENTERS THE PICTURE BY THURSDAY AND FRIDAY. SATURDAY NIGHT THROUGH MONDAY...A COLD AREA OF ARCTIC HIGH PRESSURE WILL BEGIN TO SLIDE INTO THE PLAINS SATURDAY NIGHT INTO SUNDAY AND REMAIN THROUGH AT LEAST MONDAY. THERE WILL BE A LARGE UPPER TROUGH SITUATED OVER THE PLAINS BUT ALL OF THE MOISTURE WILL BE AT THE LEADING EDGE OF THIS TROUGH AND WELL OFF TO OUR EAST. HIGH TEMPERATURES WILL BE STUCK IN THE 20S ON SUNDAY AND POSSIBLY MONDAY AS WELL. SOME AREAS THAT ARE COMPLETELY FREE OF SNOW COVER MAY REACH THE LOWER 30S ON MONDAY. TUESDAY AND WEDNESDAY...THE 12Z ECMWF PUSHES THE SFC HIGH OFF TO OUR SOUTH ALLOWING FOR WEST SOUTHWEST DOWNSLOPE SFC WINDS. THE SHALLOW COLD AIR WILL GRADUALLY MODERATE WITH HIGH TEMPERATURES BACK INTO THE 30S ON TUESDAY AND PROBABLY 40S BY WEDNESDAY. THURSDAY THROUGH FRIDAY...THERE IS A SUBSTANTIAL AMOUNT OF MODEL UNCERTAINTY WITH REGARD TO TEMPERATURES. HOWEVER...THERE IS GOOD MODEL AGREEMENT IN DRY CONDITIONS. THE ECMWF BRINGS A COLD FRONT THROUGH WEDNESDAY NIGHT WITH STRONG COLD AIR ADVECTION ON THURSDAY. THE 850 MB TEMPERATURES THURSDAY EVENING RANGE FROM -15C ON THE 12Z ECMWF TO 5C ON THE 12Z GFS FOR A SIGNIFICANT 20C DEGREE SPREAD. THE OFFICIAL FORECAST IS SOMEWHERE IN THE MIDDLE OF THESE TWO MODELS CALLING FOR ABOVE FREEZING HIGHS IN THE UPPER 30S TO LOWER 40S. HOWEVER...THESE HIGHS MAY VERY WELL BE TOO WARM. THE ONGOING STRATOSPHERIC WARMING EVENT WILL LIKELY RESULT IN THE TRANSITION TO A NEGATIVE ARCTIC OSCILLATION PATTERN...WHICH TENDS TO BRING THE COLD AIR DOWN OUT OF CANADA INTO THE EASTERN TWO THIRDS OF THE CONUS. THEREFORE...I WOULD LEAN MORE TOWARDS THE ECWMF AND THE POSSIBILITY OF COLDER TEMPERATURES THAN WHAT WE ARE OFFICIALLY CALLING FOR AS THIS BETTER FITS THE -AO PATTERN. IF THE 12Z ECMWF COLDER TREND CONTINUES...WE WILL NEED TO BE LOWERING OUR THURSDAY AND FRIDAY HIGH TEMPERATURES. && .GID WATCHES/WARNINGS/ADVISORIES... NE...WIND ADVISORY UNTIL 1 AM CST SATURDAY FOR NEZ039>041-046>049. KS...NONE. && $$ AVIATION/UPDATES...BRYANT SHORT...HALBLAUB LONG...WESELY
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
859 PM EST SUN JAN 13 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE MIDWEST AND NOSE INTO THE OHIO VALLEY FOR THE BEGINNING OF THE WEEK. A WEAK COLD FRONT WILL SKIRT THE NORTHEAST OHIO VALLEY WEDNESDAY NIGHT AND THURSDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... COLD FRONT EXTENDS ACROSS THE FAR EASTERN COUNTIES AND WILL MOVE OUT OF THE AREA IN THE NEXT COUPLE OF HOURS. RADAR SHOWS A SHARP EDGE TO THE RAIN WHICH IS LAGGING THE FRONT BY A FEW HOURS. EXPECT THE RAIN TO COME TO AN END BY 06Z. WITH THIS QUICK CUTOFF IT APPEARS THAT PRECIPITATION WILL END BEFORE TEMPERATURES ARE COLD ENOUGH FOR ANY WINTRY MIX. TIGHT GRADIENT IMMEDIATELY BEHIND THE COLD FRONT HAS RESULT IN GUSTY WINDS. THESE SHOULD GRADUALLY DIMINISH AS GRADIENT RELAXES. SATELLITE SHOWS CLEARING WORKING INTO WESTERN INDIANA. RAP FORECASTS SEEM TO HAVE A REASONABLE HANDLE ON THIS LOW LEVEL MOISTURE. THIS SUGGESTS THAT CLEARING WILL WORK INTO THE FORECAST AREA LATER TONIGHT. FORECAST LOWS LOOK REASONABLE WITH SOME MINOR ADJUSTMENTS TO TEMPERATURE DROP. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... I WAS UNABLE TO GO AS LOW ON THE CLOUD COVER WITH THE HIGH PRESSURE BUILDING IN AS I WOULD LIKE. THOUGHT THE MOISTURE BUILDING IN FROM THE NORTHWEST ON TUESDAY AND THE INCREASED MOISTURE FROM THE SOUTHEAST ON MONDAY WOULD BATTLE FOR AT LEAST SOME CLOUD COVER OVER THE REST OF THE CWA FOR SOME POINT IN TIME. A VORTICITY MAXIMA IS NOTED SOMEWHAT AT H5 AND WILL SKIRT SOUTHEAST CWA MONDAY EVENING...INCREASING THE THREAT FOR A PASSING SNOW SHOWER FOR JUST A FEW COUNTIES SOUTH OF CHILLICOTHE AND EAST OF MAYSVILLE. BOTH NAM AND GFS ARE HINTING AT A WEAK SHORTWAVE WITH THIS VORT IN THE MEAN SOUTHWEST FLOW. HIGH PRESSURE STRENGTHENING IN THE WAKE OF THE COLD FRONT WILL HELP USHER IN MORE SEASONAL AND SIGNIFICANTLY COLDER TEMPERATURES TO THE REGION. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... FORECAST PERIOD BEGINS WITH SFC HIGH PRESSURE RIDGING OVER THE FA. THIS RIDGING GETS SHUNTED E QUICKLY ON WEDNESDAY AS A CDFNT SWINGS THRU THE GREAT LAKES WED AFTN. MODELS ARE KEEPING THE BEST LIFT N OF THE FA WITH THIS SYSTEM...SO KEPT THE FCST DRY. HIGH PRESSURE BUILDS BACK INTO THE OH AND TN VALLEYS THU INTO FRI. ENERGY KEEPS RUNNING THROUGH THE SUBTLE ERN U.S. LONGWAVE TROF OVER THE WEEKEND. GFS AND ECMWF DIFFER ON THE STRENGTH OF A SYSTEM ON SATURDAY....BUT BOTH PUSH COOLER AIR IN ON SUNDAY WITH A TRAILING COLD FRONT. ONCE AGAIN THE MOISTURE IS LOOKING LIMITED FOR SUNDAY...SO KEPT THE FCST DRY. AS FOR TEMPERATURES...THE HIGH PRESSURE RIDGE ON WEDNESDAY WILL ALLOW HIGHS TO CREEP INTO THE UPPER 30S TO LOWER 40S. COOLER AIR BEHIND WEDNESDAYS SYSTEM WILL FILTER IN FOR THU...DROPPING HIGHS INTO 30S. THE SEE-SAW TEMPERATURES WILL CONTINUE...AS A WARMER AIR WORKS BACK IN FOR FRIDAY AND SATURDAY. HIGHS FRIDAY WILL BE IN THE UPPER 30S TO LOWER 40S...WITH 40S FOR HIGHS ON SATURDAY. TEMPERATURES WILL TAKE ANOTHER DOWN TURN ON SUNDAY AS HIGHS WILL RANGE FROM THE MID 30S IN THE N TO MID 40S IN NRN KY. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... RAIN WILL COME TO AN END AT ALL TERMINALS IN THE NEXT HOUR OR TWO. IFR/MVFR CEILINGS WILL REMAIN WITH GUSTY NORTHWEST WINDS. EXPECT CEILINGS TO LIFT A BIT BEFORE SCATTERING OUT. THIS SHOULD OCCUR BEFORE 12Z. ALTHOUGH THERE REMAINS UNCERTAINTY WITH THE POSSIBILITY OF ENOUGH LINGERING LOW LEVEL MOISTURE FOR CEILINGS TO REMAIN WELL INTO THE MORNING. WINDS WILL DECREASE THROUGH THE NIGHT. ONCE LOWER CLOUDS BREAK EXPECT VFR CONDITIONS THROUGH THE REST OF THE TAF PERIOD WITH ONLY MID CLOUDS SPREADING BACK IN LATE. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...FRANKS NEAR TERM... SHORT TERM...FRANKS LONG TERM...SITES AVIATION...
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1037 AM MST SAT JAN 12 2013 .AVIATION...18Z TAFS AREAS OF -SN AND BLSN WILL CONTINUE TO BRING AREAS OF IFR VSBY INTO THE AFTERNOON HOURS...THOUGH IMPROVING THROUGH THE DAY. VFR CONDITIONS ARE EXPECTED AREAWIDE TONIGHT INTO SUNDAY MORNING. && .PREV DISCUSSION... /ISSUED 744 AM MST SAT JAN 12 2013/ UPDATE...ARCTIC AIRMASS IN PLACE ACROSS THE REGION...WITH A DEEP NEAR SATURATED ISOTHERMAL OVERHEAD PER THE 12Z RAP SOUNDING. FORECAST MODELS CONTINUE TO PROG LINGERING LARGE SCALE LIFT OVER THE FA THROUGH THE DAY IN Q-VECTOR ANALYSIS. GIVEN THE DEEP NEAR SATURATED PROFILES EXPECTED TO REMAIN IN PLACE THROUGH EARLY TO MID AFTERNOON...HAVE UPDATED THE FORECAST TO MENTION LIGHT SNOW LIKELY IN THE MORNING...TRENDING TO CHANCE IN THE AFTERNOON FOR MOST OF THE FA. GIVEN COLD PROFILES OUTSIDE THE DGZ...SMALL CRYSTAL PRODUCTION FAVORED...SUGGESTING COLUMNS/SMALL PLATES OR VERY LIGHT SNOWFALL. ALL ELSE IN GOOD SHAPE. PREV DISCUSSION... /ISSUED 327 AM MST SAT JAN 12 2013/ DISCUSSION...WATER VAPOR SHOWS ELONGATED TROF EXTENDING FROM THE CA BAJA THROUGH THE NRN PLAINS. AT THE SURFACE...TIGHT PRES GRADS CONTINUE TO PRODUCE GUSTY NW WINDS ACRS THE CWFA. MAIN LOW CENTER HAS SHIFTED INTO THE UPPER MIDWEST...ALTHOUGH DEFORMATION ZONE ACROSS WRN SD CONTINUES TO PRODUCE LIGHT SNOW ACROSS OUR AREA. WIND CHILLS HAVE DROPPED TO 15 BELOW TO 30 BELOW ZERO. TODAY...WEAK LIFT WILL CONTINUE TO PRODUCE SOME LIGHT SNOW ACROSS THE CWFA THIS MORNING ALTHOUGH ANY ADDITIONAL ACCUMULATIONS WILL REMAIN LESS THAN AN INCH. HOWEVER...WINDS GUSTING TO AROUND 40 MPH WILL CONTINUE TO PRODUCE AREAS OF BLOWING SNOW ESPECIALLY ON THE SD PLAINS THIS MORNING...ALONG WITH WIND CHILLS TO 30 BELOW. HAVE DOWNGRADED THE WINTER STORM WARNING OVER PORTIONS OF WRN SD GIVEN THE DIMINISHING SNOW...AND WILL CARRY WINTER WX ADVISORIES FOR THE ENTIRE CWFA THROUGH THE MORNING GIVEN COMBINATION OF BLOWING SNOW AND WIND CHILLS. CONDITIONS WILL IMPROVE THIS AFTERNOON AS WINDS RELAX. TONIGHT THROUGH MONDAY NIGHT...UPPER TROF AXIS WILL SHIFT ONLY SLIGHTLY EWD INTO EARLY NEXT WEEK...WITH SURFACE RIDGE DOMINATE OVER THE NRN PLAINS. THIS WILL LEAD TO ONLY A SLOW RISE IN TEMPS...WITH SNOW COVERED AREAS REMAINING SEVERAL DEGREES BELOW GUIDANCE. GENERALLY DRY CONDITIONS EXPECTED...ALTHOUGH A FEW SNOW SHOWERS POSSIBLE IN THE NRN BLKHLS SUNDAY AS A WEAK SHORT WAVE CROSSES THE REGION. EXTENDED...WARM FRONT PUSHES OVER THE REGION TUESDAY...WITH BROAD AREA OF ISENTROPIC LIFT DEVELOPING MAINLY OVER THE WRN CWA. THEREFORE...WILL KEEP PRECIP CHANCES OVER THIS AREA THRU THE DAY WITH CHANCES DIMINISHING OVERNIGHT. SOME PRECIP OVERNIGHT MAY BE FREEZING RAIN AS WARM AIR ALOFT CONTINUES TO SLIDE IN...SO WILL HAVE TO KEEP AN EYE ON THIS. FOR THE REMAINDER OF THE WEEK... WEST/NORTHWEST FLOW ALOFT SETS UP OVER THE AREA BRINGING NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES AND DRY CONDITIONS. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...NONE. WY...NONE. && $$ SHORT TERM...WFO UNR LONG TERM....WFO UNR AVIATION...13
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
744 AM MST SAT JAN 12 2013 .UPDATE...ARCTIC AIRMASS IN PLACE ACROSS THE REGION...WITH A DEEP NEAR SATURATED ISOTHERMAL OVERHEAD PER THE 12Z RAP SOUNDING. FORECAST MODELS CONTINUE TO PROG LINGERING LARGE SCALE LIFT OVER THE FA THROUGH THE DAY IN Q-VECTOR ANALYSIS. GIVEN THE DEEP NEAR SATURATED PROFILES EXPECTED TO REMAIN IN PLACE THROUGH EARLY TO MID AFTERNOON...HAVE UPDATED THE FORECAST TO MENTION LIGHT SNOW LIKELY IN THE MORNING...TRENDING TO CHANCE IN THE AFTERNOON FOR MOST OF THE FA. GIVEN COLD PROFILES OUTSIDE THE DGZ...SMALL CRYSTAL PRODUCTION FAVORED...SUGGESTING COLUMNS/SMALL PLATES OR VERY LIGHT SNOWFALL. ALL ELSE IN GOOD SHAPE. && .AVIATION...12Z TAFS AREAS OF -SN AND BLSN WILL CONT TO BRING AREAS OF IFR VIS THRU EARLY THIS MORN. CONDITIONS WILL IMPROVE THRU THE DAY AS WINDS/SNOW DIMINISH WITH MOST LOCATIONS EXPECTED TO BE VFR BY SUNSET. && .PREV DISCUSSION... /ISSUED 327 AM MST SAT JAN 12 2013/ DISCUSSION...WATER VAPOR SHOWS ELONGATED TROF EXTENDING FROM THE CA BAJA THROUGH THE NRN PLAINS. AT THE SURFACE...TIGHT PRES GRADS CONTINUE TO PRODUCE GUSTY NW WINDS ACRS THE CWFA. MAIN LOW CENTER HAS SHIFTED INTO THE UPPER MIDWEST...ALTHOUGH DEFORMATION ZONE ACROSS WRN SD CONTINUES TO PRODUCE LIGHT SNOW ACROSS OUR AREA. WIND CHILLS HAVE DROPPED TO 15 BELOW TO 30 BELOW ZERO. TODAY...WEAK LIFT WILL CONTINUE TO PRODUCE SOME LIGHT SNOW ACROSS THE CWFA THIS MORNING ALTHOUGH ANY ADDITIONAL ACCUMULATIONS WILL REMAIN LESS THAN AN INCH. HOWEVER...WINDS GUSTING TO AROUND 40 MPH WILL CONTINUE TO PRODUCE AREAS OF BLOWING SNOW ESPECIALLY ON THE SD PLAINS THIS MORNING...ALONG WITH WIND CHILLS TO 30 BELOW. HAVE DOWNGRADED THE WINTER STORM WARNING OVER PORTIONS OF WRN SD GIVEN THE DIMINISHING SNOW...AND WILL CARRY WINTER WX ADVISORIES FOR THE ENTIRE CWFA THROUGH THE MORNING GIVEN COMBINATION OF BLOWING SNOW AND WIND CHILLS. CONDITIONS WILL IMPROVE THIS AFTERNOON AS WINDS RELAX. TONIGHT THROUGH MONDAY NIGHT...UPPER TROF AXIS WILL SHIFT ONLY SLIGHTLY EWD INTO EARLY NEXT WEEK...WITH SURFACE RIDGE DOMINATE OVER THE NRN PLAINS. THIS WILL LEAD TO ONLY A SLOW RISE IN TEMPS...WITH SNOW COVERED AREAS REMAINING SEVERAL DEGREES BELOW GUIDANCE. GENERALLY DRY CONDITIONS EXPECTED...ALTHOUGH A FEW SNOW SHOWERS POSSIBLE IN THE NRN BLKHLS SUNDAY AS A WEAK SHORT WAVE CROSSES THE REGION. EXTENDED...WARM FRONT PUSHES OVER THE REGION TUESDAY...WITH BROAD AREA OF ISENTROPIC LIFT DEVELOPING MAINLY OVER THE WRN CWA. THEREFORE...WILL KEEP PRECIP CHANCES OVER THIS AREA THRU THE DAY WITH CHANCES DIMINISHING OVERNIGHT. SOME PRECIP OVERNIGHT MAY BE FREEZING RAIN AS WARM AIR ALOFT CONTINUES TO SLIDE IN...SO WILL HAVE TO KEEP AN EYE ON THIS. FOR THE REMAINDER OF THE WEEK... WEST/NORTHWEST FLOW ALOFT SETS UP OVER THE AREA BRINGING NEAR TO SLIGHTLY ABOVE AVERAGE TEMPERATURES AND DRY CONDITIONS. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...WINTER WEATHER ADVISORY UNTIL 11 AM MST /NOON CST/ THIS MORNING FOR BENNETT-BUTTE-CENTRAL BLACK HILLS-CUSTER CO PLAINS-FALL RIVER-HAAKON-HARDING-HERMOSA FOOT HILLS-JACKSON-MELLETTE- NORTHERN BLACK HILLS-NORTHERN FOOT HILLS-NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-PERKINS-RAPID CITY-SHANNON- SOUTHERN BLACK HILLS-SOUTHERN FOOT HILLS-SOUTHERN MEADE CO PLAINS-STURGIS/PIEDMONT FOOT HILLS-TODD-TRIPP-ZIEBACH. WY...WINTER WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR NORTHEASTERN CROOK-NORTHERN CAMPBELL-SOUTHERN CAMPBELL- WESTERN CROOK-WESTON-WYOMING BLACK HILLS. && $$ SHORT TERM...JOHNSON EXTENDED...77 AVIATION...77 UPDATE...JC
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AREA FORECAST DISCUSSION
NWS LA CROSSE WI
240 PM CST SAT JAN 12 2013 .SHORT TERM...TONIGHT THROUGH TUESDAY 240 PM CST SAT JAN 12 2013 THE MAIN FOCUS IN THE SHORT TERM IS WITH THE SNOW POTENTIAL TONIGHT ACROSS FAR SOUTHWEST WISCONSIN AND NORTHEAST IOWA ALONG WITH TEMPERATURES INTO EARLY NEXT WEEK. CURRENTLY...AN UPPER LEVEL TROUGH IS DIGGING SOUTH ACROSS THE PLAINS WHILE A RIDGE OF HIGH PRESSURE BECOMES MORE AMPLIFIED ACROSS THE EAST COAST. AT THE SURFACE...COLDER AIR IS DROPPING DOWN FROM CENTRAL CANADA DOWN THROUGH THE PLAINS ON THE BACK SIDE OF A LOW THAT IS MOVING INTO WESTERN QUEBEC. AN INVERTED TROUGH EXTENDS TO THE SOUTHWEST OUT OF THIS LOW AND HAS HELPED TO POOL SOME HIGHER LOW LEVEL HUMIDITY THAT HAPPENS TO BE IN THE -8C TO -12C RANGE...WHICH INTRODUCES ICE INTO THE CLOUD LAYER. OVERALL FORCING IS WEAK BUT ENOUGH FROM THE SURFACE TROUGH TO PRODUCE SNOW SHOWERS AND FLURRIES ACROSS THE REGION. 12.12Z NAM/GFS AND 12.18Z RAP SOUNDINGS SHOW THE THIN LOW LEVEL CLOUD LAYER STICKING AROUND OVERNIGHT INTO TOMORROW AND DEEPENING AS A LOW PRESSURE SYSTEM TRACKS TO THE NORTHEAST FROM THE SOUTHERN PLAINS ON INTO MICHIGAN TONIGHT. THE QUESTION WITH THIS SYSTEM HAS BEEN HOW FAR WEST THE SNOW WOULD MAKE IT. THE PREVIOUS RUNS OF THE ECMWF HAD BEEN THE FURTHEST WEST OVER THE PAST FEW DAYS...BUT NOW HAS COME INTO A CONSENSUS WITH WHAT THE 12.12Z NAM/GFS/GEM ARE SHOWING WITH THE TRACK FURTHER TO THE EAST WITH JUST A BRIEF PERIOD OF LIGHT SNOW OCCURRING ACROSS NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN. 12.12Z NAM/GFS AND 12.18Z RAP CROSS SECTIONS SHOWS AN ASCENDING BAND OF FRONTOGENESIS THAT IS CLOSER TO THE SURFACE TO THE SOUTHEAST AND MORE OF A MID LEVEL CIRCULATION ACROSS THE REST OF THE FORECAST AREA. THIS FORCING SHOULD BE ENOUGH TO AT LEAST PRODUCE SOME FLURRIES...BUT CAN NOT COMPLETELY RULE OUT THAT SOME SNOW COULD MAKE IT FURTHER WEST DEPENDING ON HOW STRONG THE CIRCULATION GETS. THE SNOW WILL DEVELOP NORTHWARD THIS EVENING BEFORE QUICKLY GETTING SHUNTED OFF TO THE EAST BY DAY BREAK. ACCUMULATIONS ARE EXPECTED TO BE ON THE LIGHT SIDE AT LESS THAN AN INCH ACROSS GRANT COUNTY. AFTER THIS SYSTEM MOVES THROUGH...THE COLD AIR WILL MOVE IN ACROSS THE REGION FROM THE NORTHWEST AND LINGER INTO THE EARLY PART OF NEXT WEEK. HOW FAR TEMPERATURES ARE ABLE TO DROP IS OF QUESTION RIGHT NOW SINCE MOST OF THE AREAS SNOW PACK HAS ERODED DUE TO THE FOG...WIND...RAIN AND WARM AIR THAT WAS AROUND EARLIER THIS WEEK. HAVE NOT MADE MANY ADJUSTMENTS TO THE GOING FORECAST WITH SUNDAY LOOKING LIKE THE COLDEST DAY OVER THE NEXT WEEK. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY 240 PM CST SAT JAN 12 2013 THE NEXT CHANCE FOR SNOW COMES IN TUESDAY NIGHT INTO WEDNESDAY AS A MID LEVEL SHORT WAVE TROUGH DIVES DOWN FROM NORTHWEST CANADA DOWN INTO THE UPPER MISSISSIPPI RIVER VALLEY. THERE ARE SOME DIFFERENCES BETWEEN THE LONG TERM GUIDANCE WITH THIS SYSTEM WITH THE 12.12Z GFS SHOWING A MUCH MORE COMPACT TROUGH THAT COMES THROUGH FASTER THAN WHAT THE 12.12Z ECMWF IS ADVERTISING. THIS LEADS TO A DEEPER SURFACE LOW THAT DIVES FURTHER SOUTH ON THE GFS COMPARED TO THE ECMWF AS WELL. BECAUSE OF THESE DIFFERENCES...HAVE NOT HIT THE PRECIPITATION CHANCES TO HIGH YET...BUT OVERALL THE BETTER CHANCES FOR SEEING THE SNOW WILL BE ACROSS THE NORTHERN PORTION OF THE FORECAST AREA. WITH THERE NOT BEING MUCH OF A SHIFT IN THE UPPER LEVEL PATTERN...THERE COULD BE A FEW MORE CHANCES OF LIGHT SNOW NEXT WEEK BUT MUCH OF THE FORCING APPEARS TO BE GOING JUST NORTH OF THE REGION. WITH THE PATTERN NOT SHIFTING MUCH...TEMPERATURES WILL NOT VARY MUCH EITHER AND REMAIN FAIRLY SEASONAL. && .AVIATION...THROUGH 18Z SUNDAY 1142 AM CST SAT JAN 12 2013 DEEP LOW PRESSURE WILL WEAKEN AND CONTINUE MOVING FARTHER EAST INTO ONTARIO. WITH LINGERING CYCLONIC FLOW AND COLD AIR ADVECTION ACROSS THE AREA...PLAN ON MVFR CLOUDS ALONG WITH SCATTERED FLURRY ACTIVITY TO CONTINUE INTO THIS EVENING. EXPECTING WINDS TO SUBSIDE THROUGH THE DAY AS PRESSURE GRADIENT BECOMES MORE RELAXED. ANOTHER WEAKER WAVE OF LOW PRESSURE WILL THEN RIPPLE NORTHEAST FROM THE SOUTHERN PLAINS INTO THE GREAT LAKES REGION TONIGHT THROUGH SUNDAY MORNING. WITH THIS TRACK...EXPECTING ANY ACCUMULATING SNOW TO REMAIN SOUTH OF THE AREA. BUFKIT SOUNDING DATA CONTINUES TO SHOW MVFR CLOUD COVER AND FLURRIES LINGERING THROUGH 18Z SUNDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... 240 PM CST SAT JAN 12 2013 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...DAS
AREA FORECAST DISCUSSION
NWS NEW YORK NY
424 AM EST MON JAN 14 2013 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE REGION THIS MORNING AND THEN BECOME STATIONARY TO OUR SOUTH TONIGHT THROUGH WEDNESDAY AS A SERIES OF WEAK WAVES OF LOW PRESSURE RIDE ALONG IT. A COLD FRONT CROSSES THE TRI-STATE ON THURSDAY WITH CANADIAN HIGH PRESSURE BUILDING IN FOR THURSDAY NIGHT THROUGH SATURDAY. ANOTHER COLD FRONT MOVES ACROSS THE TRI-STATE ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... COLD FRONT APPROACHING CENTRAL PA AS OF 08Z WITH TEXTBOOK WIND SHIFT AND TEMP FALLS. AREA OF LIGHT RAIN OVER EASTERN PA RIDING NORTH WILL PROVIDE MEASURABLE PCPN FOR NORTHWEST ZONES THROUGH 11Z BEFORE WEAKENING. 05Z HRRR RUN DEPICTS FRONT NICELY IN ITS REFLECTIVITY FIELDS...THOUGH DO NOT EXPECT THIS TO PRODUCE MUCH MORE THAN SPRINKLES. IN FACT...ONLY CHANCE POPS FOR MEASURABLE PCPN AFTER 11Z OVER THE WESTERN TWO THIRDS OF THE REGION WITH THE MAIN PCPN BEING SPOTTY LIGHT DRIZZLE/SPRINKLES. FRONT CLEARS MONTAUK BY 18Z WITH FOG/DRIZZLE ALL ENDED BY NOON. AS FOR FOG ADVISORY...HAVE SPLIT THAT UP FOR TIMING. I WAS GOING THE CITY AND LONG ISLAND...BUT BASED ON LATEST LAMP GUIDANCE...HAVE KEPT IT. HAVE UNDER CUT MOS NUMBERS BASED PRIMARILY BASED ON 15 DEGREE DROP SEEN ON WITH THE FROPA IN WESTERN PA AND EASTERN OH. DESPITE THIS...STILL THINK WE CAN REACH THE LOWER 50S WITH DOWNSLOPE AND NORTHERLY FLOW...THOUGH CONFIDENCE IS LOW AND WOULD NOT BE SHOCKED WITH A BUST AND TEMPS STAYING IN THE 40S. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... UNCERTAINTY CONTINUES TONIGHT AS MOISTURE SPREADS NORTHEAST ALONG THE STALLED FRONT. OUR REGION IS ON THE NORTHERN EDGE OF THE PCPN WITH THIS FEATURE. 00Z NAM AND WRF ARW SUPPORT A DRY SOLUTION WITH GEM/GFS/WRF-ARW/AND MANY SREF MEMBERS SUPPORTING LGT PCPN FOR THE SOUTHERN THIRD OF THE FCST AREA. THERE IS AN IMPRESSIVE 170+KT SUBTROPICAL JET STREAK COMING OUT OF TX WHICH PLACES THE REGION IN THE RIGHT FRONT QUADRANT THAT WOULD HELP BUILD THE SFC HIGH AND AND BRING IN DRIER AIR. BUT THE NWP QPF GUIDANCE CAN NOT BE IGNORED. HAVE THUS GONE WITH A TIGHT GRADIENT OF POPS AND USED LIKELY FOR THE SOUTHERN PARTS OF THE CITY AND LONG ISLAND. THERMAL PROFILES SUPPORT SOME MIXING OF SLEET TO THE NORTH OF THE CITY AND LONG ISLAND...BUT IMPACT IS EXPECTED TO BE MINIMAL IF THE SLEET OCCURS AT ALL. TONUGHT`S LOW TEMPS WERE A BLEND OF NAM AND GFS MOS WITH ADJUSTMENTS UP DUE TO EXPECTED EXTENSIVE CLOUD COVER. WEAK HIGH PRESSURE BUILDS IN BRIEFLY FOR TUESDAY. TEMPS WERE AGAIN A BLEND OF MOS - NO ADJUSTMENTS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... INCREASING CONSENSUS AMONG THE MODELS THAT THE REGION WILL EXPERIENCE LIGHT TO MODERATE PRECIPITATION TUESDAY NIGHT INTO WEDNESDAY AS A WAVE OF LOW PRESSURE PASSES TO OUR SOUTH ALONG A STALLED FRONTAL BOUNDARY. HAVE CHANCE POPS N AND LIKELY POPS S IN THIS TIME FRAME. FOR NOW...BASED ON A BLEND OF NAM/GFS/ECMWF LOW LEVEL THERMAL PROFILES - APPEARS WILL BE A MIX OF RAIN/SNOW/SLEET ACROSS NYC/LONG ISLAND/MOST OF NE NJ CHANGING TO ALL RAIN WEDNESDAY MORNING...AND A MIX OF SNOW/SLEET CHANGING TO ALL RAIN BEFORE ENDING WEDNESDAY AFTERNOON. FOR NOW THINKING SUB-ADVISORY AMOUNTS ARE MOST LIKELY...BUT THERE IS SOME POTENTIAL FOR ADVISORY LEVEL ACCUMULATION ACROSS NORTHERN INTERIOR ZONES. WILL CONTINUE TO MONITOR. USED A BLEND OF NAM/GFS MOS AND 2-METER TEMPERATURES FOR LOWS TUESDAY NIGHT AND HIGHS WEDNESDAY...WITH LOWS BETWEEN...5 AND 10 DEGREES ABOVE NORMAL AND HIGHS A FEW DEGREES ABOVE NORMAL. THE REGION WILL BE AT THE BASE OF A 500 HPA TROUGH ANCHORED WITH THE POLAR VORTEX OVER HUDSON BAY WEDNESDAY NIGHT-THURSDAY NIGHT. THE BASE OF THE TROUGH LIFTS FRIDAY WITH ZONAL FLOW GIVING WAY TO SW FLOW/SLIGHT RIDGING ALOFT BY LATE SATURDAY. THE GFS IS FASTER THAN THE ECMWF IN BRINGING IN THE NEXT RE-ENFORCING SHOT OF COLD AIR - SATURDAY NIGHT VICE DURING THE DAY ON SUNDAY. HOWEVER...WITHOUT ANY CLEAR INDICATION OF ONE MODEL BEING MORE RIGHT THAN THE OTHER...HAVE OPTED FOR A GFS/ECMWF BLEND IN THIS TIME FRAME. OTHER THAN POSSIBLY SOME FLURRIES UNDER THE COLD POOL THURSDAY/THURSDAY NIGHT - NOT CONFIDENT ENOUGH IN THIS TO REFLECT IN THE FORECAST AT THIS TIME...AND A SLIGHT CHANCE OF SNOW SHOWERS WITH THE ARRIVAL OF THE COLD AIR SUNDAY OVER FAR W ZONES...IT APPEARS LOW LEVELS WILL BE TOO DRY TO SUPPORT ANY PRECIPITATION WEDNESDAY NIGHT-SUNDAY. FOR TEMPERATURES WEDNESDAY NIGHT-SUNDAY USED A BLEND OF MEX/MEX ENSEMBLE MEAN/ECE/HPC GUIDANCE. TEMPERATURES TREND FROM 5-10 DEGREES ABOVE NORMAL AT THE START OF THIS TIME FRAME TO SLIGHTLY BELOW NORMAL ON FRIDAY...THEN REBOUND TO A TAD ABOVE NORMAL FOR THE WEEKEND. DEPENDING ON EXACTLY WHEN THE COLD AIR MOVES IN SUNDAY...COULD END UP BEING BELOW NORMAL THEN...BUT TOO MUCH UNCERTAINTY TO FORECAST THAT AT THIS TIME. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... A COLD FRONT APPROACHES EARLY THIS MORNING...AND PASSES THROUGH AFTER DAYBREAK. HIGH PRESSURE GRADUALLY BUILDS INTO THE REGION FROM THE WEST THROUGH TONIGHT. ABUNDANT LOW-LEVEL MOISTURE AND LIGHT WINDS AHEAD OF AN APPROACHING COLD FRONT HAVE RESULTED WIDESPREAD LIFR OR LOWER CONDITIONS IN STRATUS/FOG/DZ. MODERATE TO HIGH CONFIDENCE IN THIS CONTINUING TILL DAYBREAK...HOWEVER THERE MAY BE BRIEF PERIODS OF CHANGING CONDITIONS. CONDITIONS EXPECTED TO IMPROVE A BIT TOWARDS DAYBREAK...PARTICULARLY ACROSS THE NYC/NJ METRO TERMINALS WHERE SW WINDS AT 1-2 KFT INCREASE TO 30-40 KT. THIS MIGHT PROMOTE ENOUGH TURBULENT MIXING TO SLIGHTLY IMPROVED VSBY/CIGS TO IFR. IN ADDITION...THERE COULD BE SOME MARGINAL LOW LEVEL WIND SHEAR ISSUES. COLD FRONT WILL PUSH ACROSS THE REGION JUST AFTER DAYBREAK...WITH CONDITIONS SLOWLY IMPROVING AT FIRST...THEN VSBY QUICKLY BECOMING VFR AROUND 15Z-16Z. TIMING OF LIFR/IFR CIGS IMPROVEMENT COULD BE OFF BY AN HOUR OR SO DEPENDING ON STRENGTH OF DRY AIR ADVECTION BEHIND THE FRONT. HIGH CONFIDENCE IN VFR BY THIS AFTERNOON. NW WINDS 10-15G20KT EXPECTED...MAINLY RIGHT OF 310 MAGNETIC. WINDS GRADUALLY WEAKEN THIS EVENING AND VEER N. A WEAK WAVE RIDING TO THE SOUTH WILL LIKELY RESULT IN INCREASING HIGH/MID CLOUDS THIS EVENING...WITH A FEW SHOWERS POSSIBLE AFTER MIDNIGHT ACROSS SOUTHERN TERMINALS. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: AMENDMENTS EXPECTED THIS MORNING FOR CHANGING FLIGHT CATEGORIES - VARIABLE CIGS AND VSBYS. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: AMENDMENTS EXPECTED THIS MORNING FOR CHANGING FLIGHT CATEGORIES - VARIABLE CIGS AND VSBYS. KLGA FCSTER COMMENTS: AMENDMENTS EXPECTED THIS MORNING FOR CHANGING FLIGHT CATEGORIES - VARIABLE CIGS AND VSBYS. KTEB FCSTER COMMENTS: AMENDMENTS EXPECTED THIS MORNING FOR CHANGING FLIGHT CATEGORIES - VARIABLE CIGS AND VSBYS. KHPN FCSTER COMMENTS: MEDIUM TO HIGH CONFIDENCE OF LIFR OR LESS UNTIL 13Z...THEN GRADUAL IMPROVEMENT EXPECTED. KISP FCSTER COMMENTS: MEDIUM TO HIGH CONFIDENCE OF LIFR OR LESS UNTIL 13Z...THEN GRADUAL IMPROVEMENT EXPECTED. .OUTLOOK FOR 06Z TUE THROUGH FRI... .LATE TONIGHT-TUE MORNING...LOW PROB FOR MVFR CONDS...ESPECIALLY LATE TONIGHT FOR NYC METRO AND LONG ISLAND...AS WEAK LOW PRESSURE PASSES TO THE SOUTH. PCPN TYPE SHOULD BE MOSTLY RAIN...BUT SOME SNOW COULD MIX IN. .TUE AFTERNOON/EVENING...VFR. .LATE TUE NIGHT-WED MORNING...SLIGHT CHANCE FOR MVFR CONDS FOR NYC METRO AND LONG ISLAND...AS ANOTHER WEAK LOW PASSES TO THE SOUTH. .WED AFTERNOON-FRI...VFR. COLD FROPA THU EVENING...FOLLOWED BY GUSTY NW WINDS THU NIGHT-FRI. && .MARINE... THE DENSE FOG ADVISORY REMAINS UP THROUGH THE MORNING. COLD FRONT PASSES MID TO LATE MORNING AND WHILE THERE MAY BE A GUST TO THE MID 20S...THIS WOULD ONLY BE WITH THE FRONT ITSELF. SEAS IN A SE SWELL ARE AROUND 4 FEET ON THE OCEAN AT MOST...THUS THE SMALL CRAFT ADVISORY FOR THE OCEAN HAS BEEN DROPPED. A LIGHT PRESSURE GRADIENT ACROSS THE REGION WILL PROMOTE WINDS 10 KT OR LESS TUESDAY INTO WEDNESDAY. STRONG COLD ADVECTION WILL SEE SMALL CRAFT CONDITIONS AND POSSIBLY GALE FORCE GUSTS ON ALL WATERS WEDNESDAY NIGHT AND POSSIBLY INTO THURSDAY. SUB-SMALL CRAFT CONDITIONS SHOULD RETURN TO ALL WATERS BY FRIDAY. && .HYDROLOGY... LIGHT PCPN IS EXPECT THIS MORNING AND AGAIN OVERNIGHT. A 1/4 OF AN INCH OF LIQUID EQUIVALENT...AND POSSIBLY A BIT MORE OVER LONG ISLAND AND NYC...IS EXPECTED OVER THE REGION TUESDAY NIGHT AND WEDNESDAY. NO HYDROLOGIC IMPACTS ARE EXPECTED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR CTZ006>008- 010>012. DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR CTZ005-009. NY...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR NYZ078>081- 177-179. DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR NYZ067>075- 176-178. NJ...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR NJZ002-004- 006-103>108. MARINE...DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR ANZ330-335-338-340- 345-350-353-355. && $$ SYNOPSIS...TONGUE NEAR TERM...TONGUE SHORT TERM...TONGUE LONG TERM...MALOIT AVIATION...BC/NV MARINE...MALOIT/TONGUE HYDROLOGY...TONGUE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1259 AM EST MON JAN 14 2013 .SYNOPSIS... A COLD FRONT OVER WESTERN PENNSYLVANIA APPROACHES OVERNIGHT. THE FRONT MOVES SOUTH AND EAST BY AFTERNOON AND THEN BECOMES STATIONARY TO OUR SOUTH TONIGHT THROUGH WEDNESDAY WITH A SERIES OF WEAK WAVES OF LOW PRESSURE RIDING ALONG IT. HIGH PRESSURE RETURNS ON THURSDAY...FOLLOWED BY A COLD FRONT PASSING THROUGH THURSDAY NIGHT. HIGH PRESSURE THEN REMAINS IN CONTROL INTO THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... FRONT IS NEARING KPIT AS OF 0530Z AND IS ACCELERATING WITH G30 KT IN IT`S WAKE. THUS ARRIVAL IN THE WESTERN THIRD OF THE CWA BY SUNRISE SEEMS LIKELY. WILL CONTINUE THE DENSE FOG ADVISORY AND HAVE MADE THE DRIZZLE PERSISTENT. VSBYS ARE FLUCTUATING UP TO 3 MILES AT KEWR...BUT WILL NOT TRY TO CHASE THINGS WITH MOS STILL SUGGESTING LOWERING TOWARDS SUNRISE. PCPN WITH THE FRONT DIMINISHES AS IT APPROACHES PER ALL LATEST NWP. HRRR DOES HAVE BAND OF LIGHT PCPN MAKING TO THE CT/LONG ISLAND AREAS...BUT BELIEVE THIS IS OVER DONE. DRIZZLE IS THE MAIN PCPN PRODUCER. WARM ADVECTION ALOFT WILL CONTINUE TO SUPPORT DRIZZLE AND FOG UNTIL THE FRONT DOES PASS WITH STEADY TEMPS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... COLD FRONT PUSHES DRIZZLE...FOG AND ANY LIGHT RAIN OUT OF THE REGION BY NOON FROM NORTHWEST TO SOUTHEAST. CLEARING BY MIDDAY. A GUSTY NW FLOW ON THE BACKSIDE THIS AFTN. HIGHS WILL GET UP TO AROUND 50 INLAND...AND THE LOW TO MID 50S AT THE COAST. THE STRONGEST COLD ADVECTION FOLLOWS IN THE AFT/EVE... WHICH ALLOWS THE AIR MASS TO WARM UP WELL ABOVE SEASONABLE LEVELS. GUSTS IN THE AFT WILL BE UP TO 20 MPH. A WEAK WAVE OF LOW PRESSURE PASSES WELL SOUTH AND EAST LATE MON NIGHT WITH SOME LIGHT PCPN...MAINLY NEAR THE COAST...BUT HAVE PUSHED BACK THE TIMING TO AFT 9 PM. AS THE COLD AIR FILTERS IN...ANY PCPN THAT DOES FALL MAY MIX WITH SOME SLEET OR SNOW. NO ACCUM IS EXPECTED. THERE COULD HOWEVER BE A FEW SLICKS SPOTS FOR THE MORNING COMMUTE TUE. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... MOISTURE SHIFTS TO THE SOUTH THROUGH TUESDAY. THIS IS IN ASSOCIATION WITH A STALLING FRONTAL BOUNDARY TO OUR SOUTH. THEREFORE...ONLY A SLIGHT CHANCE OF PCPN OVER THE LAND AREAS DURING THE MORNING...THEN DRY IN THE AFTERNOON. AS FOR PCPN TYPE...BY DAYBREAK ON TUESDAY...A WARM NOSE ALOFT ERODES AND WOULD LIKELY SUPPORT EITHER SNOW...SLEET OR A MIXTURE OF THE TWO. THEN BY LATE MORNING...THE BOUNDARY LAYER WOULD WARM UP ENOUGH FOR RAIN BEING MIXED WITH THE WINTRY PCPN. IN ANY CASE...POPS AND QPF ARE LOW. HIGH TEMPERATURES STILL END UP A LITTLE ABOVE NORMAL. A WAVE OF LOW PRESSURE THEN MOVES ALONG THE FRONTAL BOUNDARY TUESDAY NIGHT INTO WEDNESDAY...BUT AGAIN...ONLY A LOW CHANCE OF PCPN...AND FOCUSED LATE AT NIGHT INTO WEDNESDAY MORNING. SNOW WOULD BE THE MOST LIKELY PCPN TYPE UNTIL MID-MORNING...THEN EVENTUALLY A CHANGE TO RAIN BY THE AFTERNOON IF THERE`S ANY LINGERING PCPN. FOR THURSDAY...A COLD FRONT PASSES THROUGH IN THE EVENING. MAYBE A SPRINKLE IN THE AFTERNOON...THEN A SPRINKLE OR FLURRY IN THE EVENING. HIGH PRESSURE OTHERWISE REMAINS THE DOMINANT FEATURE FOR OUR WEATHER THROUGH THE UPCOMING WEEKEND. A COLD FRONT COULD BRING PCPN OUR WAY ON SUNDAY...BUT WILL GO WITH A DRY FORECAST FOR NOW AS MOISTURE APPEARS TO BE LACKING. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... A COLD FRONT APPROACHES EARLY THIS MORNING...AND PASSES THROUGH AFTER DAYBREAK. HIGH PRESSURE GRADUALLY BUILDS INTO THE REGION FROM THE WEST THROUGH TONIGHT. ABUNDANT LOW-LEVEL MOISTURE AND LIGHT WINDS AHEAD OF AN APPROACHING COLD FRONT HAVE RESULTED IN THE RE-DEVELOPMENT OF WIDESPREAD LIFR OR LOWER CONDS IN STRATUS/FOG/DZ. MODERATE TO HIGH CONFIDENCE IN THIS CONTINUING TILL DAYBREAK. THERE IS SOME UNCERTAINTY IF THESE CONDS IMPROVE A BIT TOWARDS DAYBREAK THOUGH...PARTICULARLY NYC/NJ METRO TERMINALS AS SW WINDS AT 1-2 KFT INCREASE TO 30-40 KT. THIS MIGHT PROMOTE ENOUGH TURBULENT MIXING TO SLIGHTLY IMPROVED VSBY/CIGS TO IFR. IN ADDITION...THERE COULD BE SOME MARGINAL LOW LEVEL WIND SHEAR ISSUES. COLD FROPA STILL EXPECTED JUST AFTER DAYBREAK...WITH CONDS SLOWLY IMPROVING AT FIRST...THEN VSBY QUICKLY BECOMING VFR AFTER ABOUT 15Z-16Z. TIMING OF LIFR/IFR CIGS IMPROVEMENT COULD BE OFF BY AN HOUR OR SO DEPENDING ON STRENGTH OF DRY AIR ADVECTION BEHIND THE FRONT. HIGH CONFIDENCE IN VFR BY THIS AFTERNOON. NW WINDS 10-15G20KT EXPECTED...MAINLY RIGHT OF 310 MAGNETIC. WINDS GRADUALLY WEAKEN THIS EVENING AND VEER N. A WEAK WAVE RIDING TO THE SOUTH WILL LIKELY RESULT IN INCREASING HIGH/MID CLOUDS THIS EVENING...WITH A FEW SHOWERS POSSIBLE AFTER MIDNIGHT ACROSS SOUTHERN TERMINALS. .OUTLOOK FOR 06Z TUE THROUGH FRI... .LATE TONIGHT-TUE MORNING...LOW PROB FOR MVFR CONDS...ESPECIALLY LATE TONIGHT FOR NYC METRO AND LONG ISLAND...AS WEAK LOW PRESSURE PASSES TO THE SOUTH. PCPN TYPE SHOULD BE MOSTLY RAIN...BUT SOME SNOW COULD MIX IN. .TUE AFTERNOON/EVENING...VFR. .LATE TUE NIGHT-WED MORNING...SLIGHT CHANCE FOR MVFR CONDS FOR NYC METRO AND LONG ISLAND...AS ANOTHER WEAK LOW PASSES TO THE SOUTH. .WED AFTERNOON-FRI...VFR. COLD FROPA THU EVENING...FOLLOWED BY GUSTY NW WINDS THU NIGHT-FRI. && .MARINE... THE DENSE FOG ADVISORY REMAINS UP THROUGH THE NIGHT FOR VISIBILITIES 1 NM OR LESS. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA THROUGH THE OVERNIGHT. WINDS PRECEDING A COLD FRONTAL PASSAGE IN THE MORNING WILL PRODUCE MARGINAL SCA WINDS AND SEAS ACROSS THE OCEAN WATERS EAST OF FIRE ISLAND INLET. CONFIDENCE IN THIS SCENARIO IS WANING AND IT IS QUITE POSSIBLE THAT SCA CONDITIONS ARE NOT MET. A GUSTY NW FLOW MON AFT/ERLY EVE WILL GET UP TO AROUND 20 KT BEFORE DIMINISHING LATE AS HIGH PRESSURE NOSES IN FROM THE OHIO VALLEY. RELATIVELY TRANQUIL CONDITIONS PREVAIL ON TUESDAY AND WEDNESDAY. SCA CONDITIONS THEN BECOME POSSIBLE AGAIN WEDNESDAY NIGHT...AND MORE LIKELY DURING THURSDAY AS THE PRESSURE GRADIENT TIGHTENS AHEAD OF A COLD FRONT...CAUSING WINDS AND SEAS TO INCREASE. THE COLD FRONT MOVES THROUGH THURSDAY NIGHT...WITH SUB SCA CONDITIONS PROBABLE ACROSS ALL WATERS BY FRIDAY AFTERNOON. && .HYDROLOGY... THERE IS ONLY POTENTIAL FOR LIGHT PRECIPITATION AMOUNTS THROUGH THE FORECAST PERIOD. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR CTZ005>012. NY...DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR NYZ067>075- 078>081-176>179. NJ...DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR NJZ002-004- 006-103>108. MARINE...DENSE FOG ADVISORY UNTIL 7 AM EST THIS MORNING FOR ANZ330-335- 338-340-345-350-353-355. SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST THIS EVENING FOR ANZ350-353. && $$ SYNOPSIS...JC/DW NEAR TERM...JC/TONGUE/DW SHORT TERM...TONGUE/DW LONG TERM...JC AVIATION...NV MARINE...JC/DW HYDROLOGY...JC/DW
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
406 AM EST MON JAN 14 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THE FIRST PART OF THE WORK WEEK. THIS WILL LEAD TO MAINLY DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES THROUGH WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THIS AFTERNOON. AS IT DOES...NORTH TO NORTHWEST LOW LEVEL FLOW WILL DECREASE BUT WEAK CAA WILL CONTINUE THROUGH MUCH OF THE DAY. A FAIR AMOUNT OF LOW CLOUDS ARE STILL IN PLACE ACROSS THE REGION BUT SATELLITE IMAGES ARE INDICATING SOME BREAKS ACROSS PARTS OF OUR SOUTHWEST. MAIN QUESTION FOR TODAY WILL BE HOW FAST THESE CLOUDS DISSIPATE. THE RAP IS HANGING ON TO A FAIR AMOUNT OF LOW LEVEL MOISTURE THROUGH THIS AFTERNOON. THIS IS PROBABLY OVERDONE AND PREFER SOMETHING CLOSER TO WHAT THE NAM IS INDICATING ALTHOUGH THE WEAK CAA MAY HELP KEEP THE CLOUDS AROUND A BIT LONGER. WILL THEREFORE ALLOW FOR PARTIAL CLEARING HEADING THROUGH LATE MORNING INTO EARLY AFTERNOON. 500 MB MOISTURE WILL INCREASE FROM THE SOUTHWEST LATER THIS AFTERNOON AND THIS COULD ALLOW FOR AN INCREASE IN SOME HIGHER LEVEL CLOUDS LATER TODAY. WITH WEAK CAA...EXPECT HIGHS RANGING FROM THE UPPER 20S TO LOWER 30S IN THE NORTHWEST TO THE MID AND UPPER 30S ACROSS THE SOUTHEAST. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... SURFACE HIGH PRESSURE WILL REMAIN ACROSS THE AREA TUESDAY INTO WEDNESDAY...PROVIDING MAINLY DRY CONDITIONS. THE ONE EXCEPTION COULD BE ACROSS OUR FAR SOUTHEAST AS A COUPLE OF SHORT WAVES RIDE UP ALONG THE APPALACHIANS. THE MODELS HAVE TRENDED A BIT FARTHER NORTH WITH THEIR NORTHERN PERIPHERY WITH THE INITIAL WAVE TONIGHT AND THEN THE SECOND ONE FOR TUESDAY NIGHT. BOTH THE 00Z ECMWF AND GFS ARE TRYING TO BRUSH A FEW OF OUR SOUTHEASTERN COUNTIES WITH PCPN WHILE THE 00Z AND 06Z NAM ARE KEEPING EVERYTHING TO THE SOUTH. GIVEN THE TRENDS...WILL GO AHEAD AND INTRODUCE SOME POPS ACROSS THE FAR SOUTHEAST FOR TONIGHT AND TUESDAY NIGHT...BUT KEEP THEM LOW AT THIS POINT. FORECAST SOUNDINGS ARE INDICATING THE POSSIBILITY OF A RAIN/SNOW MIX WITH ANY PCPN BUT GIVEN THAT IT WOULD BE AT NIGHT...IT MAY BE MORE LIKELY TO BE SNOW THAN RAIN. CLOUDS WILL BE DEPENDENT ON JUST HOW FAR NORTH THESE WAVES MAKE IT AND THIS WILL ALSO HAVE AN AFFECT ON LOW TEMPERATURES BOTH TONIGHT AND TUESDAY NIGHT. WILL GO AHEAD AND ALLOW FOR A DECENT GRADIENT BOTH NIGHTS FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE BUILDS BACK INTO THE OH AND TN VALLEYS THU INTO FRI. ENERGY KEEPS RUNNING THROUGH THE SUBTLE ERN U.S. LONGWAVE TROF OVER THE WEEKEND. GFS AND ECMWF DIFFER ON THE STRENGTH OF A SYSTEM ON SATURDAY....BUT BOTH PUSH COOLER AIR IN ON SUNDAY WITH A TRAILING COLD FRONT. ONCE AGAIN THE MOISTURE IS LOOKING LIMITED FOR SUNDAY...SO KEPT THE FCST DRY. COOLER AIR BEHIND WEDNESDAYS SYSTEM WILL FILTER IN FOR THU...DROPPING HIGHS INTO 30S. THE SEE-SAW TEMPERATURES WILL CONTINUE...AS A WARMER AIR WORKS BACK IN FOR FRIDAY AND SATURDAY. HIGHS FRIDAY WILL BE IN THE UPPER 30S TO LOWER 40S...WITH 40S FOR HIGHS ON SATURDAY. TEMPERATURES WILL TAKE ANOTHER DOWN TURN ON SUNDAY AS HIGHS WILL RANGE FROM THE MID 30S IN THE N TO MID 40S IN NRN KY. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... MVFR CIGS WILL CONTINUE FOR THE MOST PART ACROSS THE AREA THROUGH SUNRISE. A BREAK IN THE CLOUD COVER WILL ALLOW FOR A COUPLE OF HOUR PERIOD OF VFR CONDITIONS DURING THE MIDDLE OF THE NIGHT FOR ALL TERMINALS EXCEPT KLCK/KCMH. AFTER SUNRISE THE BACK EDGE OF CLOUD COVER WILL SPREAD EAST ACROSS THE TERMINALS WITH VFR CONDITIONS AND EXPECTED THEREAFTER FOR THE REMAINDER OF THE TAF PERIOD. SOME VFR LOW TO MID LEVEL CLOUD COVER IS EXPECTED TO SPREAD ACROSS THE AREA LATE MONDAY AFTERNOON AND EVENING. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...JGL NEAR TERM...JGL SHORT TERM...JGL LONG TERM...SITES AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1226 AM EST MON JAN 14 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE MIDWEST AND NOSE INTO THE OHIO VALLEY FOR THE BEGINNING OF THE WEEK. A WEAK COLD FRONT WILL SKIRT THE NORTHEAST OHIO VALLEY WEDNESDAY NIGHT AND THURSDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... COLD FRONT EXTENDS ACROSS THE FAR EASTERN COUNTIES AND WILL MOVE OUT OF THE AREA IN THE NEXT COUPLE OF HOURS. RADAR SHOWS A SHARP EDGE TO THE RAIN WHICH IS LAGGING THE FRONT BY A FEW HOURS. EXPECT THE RAIN TO COME TO AN END BY 06Z. WITH THIS QUICK CUTOFF IT APPEARS THAT PRECIPITATION WILL END BEFORE TEMPERATURES ARE COLD ENOUGH FOR ANY WINTRY MIX. TIGHT GRADIENT IMMEDIATELY BEHIND THE COLD FRONT HAS RESULT IN GUSTY WINDS. THESE SHOULD GRADUALLY DIMINISH AS GRADIENT RELAXES. SATELLITE SHOWS CLEARING WORKING INTO WESTERN INDIANA. RAP FORECASTS SEEM TO HAVE A REASONABLE HANDLE ON THIS LOW LEVEL MOISTURE. THIS SUGGESTS THAT CLEARING WILL WORK INTO THE FORECAST AREA LATER TONIGHT. FORECAST LOWS LOOK REASONABLE WITH SOME MINOR ADJUSTMENTS TO TEMPERATURE DROP. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... I WAS UNABLE TO GO AS LOW ON THE CLOUD COVER WITH THE HIGH PRESSURE BUILDING IN AS I WOULD LIKE. THOUGHT THE MOISTURE BUILDING IN FROM THE NORTHWEST ON TUESDAY AND THE INCREASED MOISTURE FROM THE SOUTHEAST ON MONDAY WOULD BATTLE FOR AT LEAST SOME CLOUD COVER OVER THE REST OF THE CWA FOR SOME POINT IN TIME. A VORTICITY MAXIMA IS NOTED SOMEWHAT AT H5 AND WILL SKIRT SOUTHEAST CWA MONDAY EVENING...INCREASING THE THREAT FOR A PASSING SNOW SHOWER FOR JUST A FEW COUNTIES SOUTH OF CHILLICOTHE AND EAST OF MAYSVILLE. BOTH NAM AND GFS ARE HINTING AT A WEAK SHORTWAVE WITH THIS VORT IN THE MEAN SOUTHWEST FLOW. HIGH PRESSURE STRENGTHENING IN THE WAKE OF THE COLD FRONT WILL HELP USHER IN MORE SEASONAL AND SIGNIFICANTLY COLDER TEMPERATURES TO THE REGION. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... FORECAST PERIOD BEGINS WITH SFC HIGH PRESSURE RIDGING OVER THE FA. THIS RIDGING GETS SHUNTED E QUICKLY ON WEDNESDAY AS A CDFNT SWINGS THRU THE GREAT LAKES WED AFTN. MODELS ARE KEEPING THE BEST LIFT N OF THE FA WITH THIS SYSTEM...SO KEPT THE FCST DRY. HIGH PRESSURE BUILDS BACK INTO THE OH AND TN VALLEYS THU INTO FRI. ENERGY KEEPS RUNNING THROUGH THE SUBTLE ERN U.S. LONGWAVE TROF OVER THE WEEKEND. GFS AND ECMWF DIFFER ON THE STRENGTH OF A SYSTEM ON SATURDAY....BUT BOTH PUSH COOLER AIR IN ON SUNDAY WITH A TRAILING COLD FRONT. ONCE AGAIN THE MOISTURE IS LOOKING LIMITED FOR SUNDAY...SO KEPT THE FCST DRY. AS FOR TEMPERATURES...THE HIGH PRESSURE RIDGE ON WEDNESDAY WILL ALLOW HIGHS TO CREEP INTO THE UPPER 30S TO LOWER 40S. COOLER AIR BEHIND WEDNESDAYS SYSTEM WILL FILTER IN FOR THU...DROPPING HIGHS INTO 30S. THE SEE-SAW TEMPERATURES WILL CONTINUE...AS A WARMER AIR WORKS BACK IN FOR FRIDAY AND SATURDAY. HIGHS FRIDAY WILL BE IN THE UPPER 30S TO LOWER 40S...WITH 40S FOR HIGHS ON SATURDAY. TEMPERATURES WILL TAKE ANOTHER DOWN TURN ON SUNDAY AS HIGHS WILL RANGE FROM THE MID 30S IN THE N TO MID 40S IN NRN KY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... MVFR CIGS WILL CONTINUE FOR THE MOST PART ACROSS THE AREA THROUGH SUNRISE. A BREAK IN THE CLOUD COVER WILL ALLOW FOR A COUPLE OF HOUR PERIOD OF VFR CONDITIONS DURING THE MIDDLE OF THE NIGHT FOR ALL TERMINALS EXCEPT KLCK/KCMH. AFTER SUNRISE THE BACK EDGE OF CLOUD COVER WILL SPREAD EAST ACROSS THE TERMINALS WITH VFR CONDITIONS AND EXPECTED THEREAFTER FOR THE REMAINDER OF THE TAF PERIOD. SOME VFR LOW TO MID LEVEL CLOUD COVER IS EXPECTED TO SPREAD ACROSS THE AREA LATE MONDAY AFTERNOON AND EVENING. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...FRANKS NEAR TERM... SHORT TERM...FRANKS LONG TERM...SITES AVIATION...LATTO
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
323 AM CST MON JAN 14 2013 .SHORT TERM...TODAY THROUGH WEDNESDAY 322 AM CST MON JAN 14 2013 AT 3 AM...A SURFACE TROUGH WAS LOCATED ACROSS SOUTHWEST MINNESOTA. THIS TROUGH IS CURRENTLY PRODUCING A MVFR DECK OF CLOUDS ACROSS EASTERN SOUTH DAKOTA AND SOUTHWEST MINNESOTA. THERE ARE EVEN FLURRIES BEING REPORTED AT SIOUX FALLS SOUTH DAKOTA. FURTHER TO THE SOUTHWEST...THE WATER VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH MOVING OUT OF COLORADO. THIS SYSTEM HAS BEEN PRODUCING SOME LIGHT SNOW FROM COLORADO INTO CENTRAL SOUTH DAKOTA. THE 14.00Z MODELS ARE IN GOOD AGREEMENT THAT THE SURFACE TROUGH WILL MOVE SLOWLY EAST AND GRADUALLY WEAKEN TODAY. MEANWHILE THE SHORT WAVE WILL MOVE ACROSS THE AREA THIS AFTERNOON. BOTH THE GFS AND NAM/WRF SOUNDINGS SHOW LITTLE OMEGA WITH THESE SYSTEMS. MEANWHILE THE RAP HAS UP TO 5 MICROBARS OF OMEGA CO-LOCATED WITH THE DENDRITIC GROWTH ZONE. SINCE BOTH SYSTEMS ARE CURRENTLY PRODUCING SOME FLURRIES OR VERY LIGHT SNOW...WENT MORE TOWARD THE RAP AND INTRODUCED SOME SCATTERED FLURRIES FOR THIS AFTERNOON NORTHWEST OF SAINT ANSGAR IOWA TO WISCONSIN RAPIDS LINE. ON TUESDAY NIGHT AND WEDNESDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE SYSTEM WILL MOVE ALONG THE ARCTIC COLD FRONT TO OUR NORTH. AS THE WAVE APPROACHES...THE CLOUDS WILL INCREASE OVERNIGHT AND TEMPERATURES WILL SLOWLY RISE. LIKE THE PAST COUPLE OF DAYS...THE MODELS CONTINUE TO SHOW THAT THERE WILL BE ENOUGH MOISTURE FOR SOME PRECIPITATION TO DEVELOP ALONG AND NORTH OF THE INTERSTATE 90 CORRIDOR OVERNIGHT TUESDAY AND WEDNESDAY MORNING. HOWEVER SOUNDINGS CONTINUE TO STRUGGLE ON WHETHER THERE WILL BE ICE CRYSTAL SEEDING OR NOT. IN MANY CASES...WHERE THEY SHOW THE LACK OF ICE...THERE IS NO PRECIPITATION. SINCE THERE IS NO CLEAR SIGNAL...JUST KEPT THE PRECIPITATION IN THE FORM OF SNOW FOR NOW. HOWEVER A BIT CONCERNED THAT THERE MAY BE SOME LIGHT FREEZING DRIZZLE ON THE SOUTHERN PERIPHERY OF THE PRECIPITATION. ANOTHER CONCERN ON WEDNESDAY IS THE TEMPERATURES...THE NAM/WRF HAS WAY TOO MUCH SNOW COVER IN IT. THIS MODEL SHOWED 1 TO 2 INCHES OF SNOW ON THE GROUND ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA...AND 2 TO 5 INCHES OF SNOW ACROSS WESTERN WISCONSIN. COOPERATIVE REPORTS AND NOHRSC SHOW THAT WITH THE EXCEPTION OF AN INCH AT MEDFORD WISCONSIN...MUCH OF THE AREA IS SNOW FREE. DUE TO THIS...THE NAM/WRF TEMPERATURES ARE WAY TOO COLD. TYPICALLY...AT LA CROSSE THE MID-JANUARY MAXIMUM TEMPERATURES AVERAGE 10 DEGREES WARMER THAN THE LONG TERM AVERAGE /24.7 DEGREES AT KLSE/ WHEN THERE IS NO SNOW ON THE GROUND. THIS FITS IN WELL WITH A BLEND OF THE GFS/ECMWF/GEM. WOULD NOT BE SURPRISED TO SEE SOME LOWER 40S ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY 322 AM CST MON JAN 14 2013 ON THURSDAY AND THURSDAY NIGHT...THE 14.00Z MODELS CONTINUE TO STRUGGLE ON HOW FAR SOUTH THE ARCTIC FRONT WILL GET. THE GFS HAS THIS FRONT DROPPING SOUTH OF THE FORECAST AREA. MEANWHILE THE NAM/WRF KEEPS THIS FRONT NORTH OF THE FORECAST AREA. THIS IS DUE TO ANOTHER LOW PRESSURE SYSTEM QUICKLY FOLLOWING THE LOW THAT PASSES TO THE NORTH OF THE AREA ON TUESDAY NIGHT AND WEDNESDAY. MEANWHILE THE ECWMF IS A GOOD COMPROMISE BETWEEN THE TWO AND IT HAS THIS FRONT ONLY GETTING AS FAR SOUTH AS THE INTERSTATE 94 CORRIDOR. DUE TO THESE DIFFERENCES...THERE IS LOWER THAN USUAL CONFIDENCE IN THE TEMPERATURES. EVEN THE SNOWFALL FORECAST IS UNCERTAIN DUE TO THE VARIOUS TIMING OF THE WAVES AND THE PLACEMENT OF THE FRONT /THE SNOW WILL BE MAINLY CONFINED NORTH OF THIS FRONT/. ON FRIDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE AREA WILL BE PASSING NORTH OF THE AREA. THE COMBINATION OF SOUTHWEST WINDS AND SUNSHINE WILL ALLOW TEMPERATURES TO ONCE AGAIN WARM INTO THE 30S AND LOWER 40S. THE ECMWF EVEN SUGGESTS LOWER AND MID 40S. SINCE THIS HAS BEEN A CONSISTENT SIGNAL...RAISED THE ALL BLEND TEMPERATURES BY ABOUT 5 DEGREES. ON SUNDAY...THE MODELS CONTINUE TO STRUGGLE ON HOW FAR SOUTH THE ARCTIC FRONT WILL SAG SOUTHWARD INTO THE AREA. A COUPLE OF DAYS AGO THE ECMWF CONSISTENTLY SHOWED THAT THIS FRONT WOULD MOVE WELL SOUTH OF THE AREA. THE 13.12Z ECMWF BACKED AWAY FROM THIS SOLUTION...AND THE 14.00Z ECMWF HAS RETURNED BACK TO ITS COLDER SOLUTION. SINCE THERE IS SOME UNCERTAINTY ON WHERE THIS FRONT WILL BE LOCATED AND CONCERN ABOUT HOW MUCH MODERATION MAY TAKE PLACE WITH THE LACK OF SNOW ACROSS THE AREA...JUST STAYED WITH THE ALL BLEND FORECAST FOR NOW. && .AVIATION...THROUGH 06Z TUESDAY 1136 PM CST SUN JAN 13 2013 SKIES HAVE CLEARED OUT AT BOTH TAF SITES DUE TO A WEAK RIDGE OF HIGH PRESSURE THAT HAS MOVED IN. TO THE WEST...A TROUGH OF LOW PRESSURE WAS MOVING INTO WESTERN MINNESOTA. ACCOMPANYING THE TROUGH IS A BATCH OF MVFR STRATUS CROSSING FAR EASTERN SOUTH DAKOTA. MODELS ARE IN GOOD AGREEMENT BRINGING THIS STRATUS INTO KRST AROUND 16Z AND KLSE AROUND 18Z...THEN LASTING FOR 6-8 HOURS BEFORE DRIER AIR MOVES BACK IN TO SCOUR THE CLOUDS OUT. GIVEN THAT THERE WERE FLURRIES WITH THIS STRATUS DURING DAYTIME HEATING YESTERDAY...HAVE MAINTAINED FLURRY POTENTIAL IN THE TAF. LOOK FOR WINDS TO HOLD FAIRLY STEADY THROUGH 06Z TUESDAY...OUT OF THE SOUTHWEST TO WEST AT 5-10 KT. && .ARX WATCHES/WARNINGS/ADVISORIES... 322 AM CST MON JAN 14 2013 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...AJ
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
438 AM PST MON JAN 14 2013 ...COLD TEMPERATURES THIS MORNING FOR MANY LOCATIONS... .DISCUSSION...AS OF 4:15 AM PST MONDAY...HAVE CANCELLED THE FROST ADVISORY FOR SAN FRANCISCO AND THE FREEZE WARNING FOR THE SAN FRANCISCO SHORELINE. THERE HAS BEEN ENOUGH WIND TO KEEP THE ATMOSPHERE MIXED...SO WHILE THE DEW PTS ARE VERY LOW TEMPERATURES WILL REMAIN A BIT WARMER THAN EXPECTED. HAVE KEPT THE FREEZE WARNING GOING TO 9 AM FOR THE INLAND VALLEYS OF THE DISTRICT AS WELL AS THE SANTA CRUZ/MONTEREY COASTLINE. THE FREEZE WARNING FOR THE NORTH BAY VALLEYS AND THE EAST BAY VALLEYS IS MARGINAL...BUT IF THE WIND DIES OFF...TEMPERATURES WILL DROP RAPIDLY IN THE VERY DRY AIRMASS. THE HRRR MODEL AND THE 00Z WRF BOTH ARE FORECASTING LIGHT SFC WINDS THIS MORNING...SO WE WILL SEE HOW THIS PANS OUT. DRY WEATHER WILL BE THE RULE FOR THE UPCOMING WEEK. A STRONG RIDGE...CLEARLY SEEN ON WATER VAPOR IMAGERY IS CENTERED AROUND 140W...WITH THE RIDGE REACHING INTO ALASKA. INTERESTING TO NOTE HOW FAR NORTH WARM AIR IS BEING ADVECTED INTO ALASKA...FAIRBANKS IS CURRENTLY A (RELATIVELY) BALMY 28 DEGREES...WHEREAS THE AVERAGE LOW IS -14 DEGREES! IN FACT...SAN MARTIN (BETWEEN MORGAN HILL AND GILROY) IS THE SAME TEMPERATURE AS FAIRBANKS AT THIS TIME...VERY RARELY SEEN IN THE MIDDLE OF JANUARY! THE RIDGE WILL SLOWLY EDGE EAST...TO A POSITION ALONG THE COAST BY THURSDAY...THEN REMAIN OVER THE WEST COAST RIGHT THROUGH THE WEEKEND. AFTER ANOTHER COLD NIGHT TONIGHT...DEPENDING ON THE WIND...TEMPERATURES WILL SLOWLY WARM THE REMAINDER OF THE WEEK AND INTO THE WEEKEND. BOTH THE GFS AND ECMWF BEGIN TO BREAK DOWN THE RIDGE BY THE MIDDLE OF NEXT WEEK (JANUARY 23). && .AVIATION...AS OF 3:15 AM PST MONDAY...VERY DRY AIRMASS IN PLACE THIS MORNING WITH CLEAR SKIES AND VFR CONDITIONS. CURRENT TAF PACKAGE WILL CONTINUE VFR THROUGH THE FORECAST PERIOD. ONLY TRICKY PART ARE THE EASTERLY WINDS...ESP AROUND SAN FRANCISCO BAY. CONF HIGH. VICINITY OF KSFO...VFR CONDITIONS. WINDS AS OF 11Z ARE SE AROUND THE BAY. WILL KEEP SE PREVAILING...BUT MODEL GUIDANCE SUGGESTS A NE FLOW AROUND 10 KT LATER THIS MORNING. CONF IS MARGINAL AND WILL LEAVE THE NE FLOW OUT FOR NOW. WILL MONITOR AND AMEND SFO IF NEEDED. OTHERWISE...NW FLOW LATER TODAY. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR CONDITIONS. && .CLIMATE...HERE ARE THE RECORD LOW TEMPERATURES FOR JANUARY 14TH AT SELECTED LOCATIONS... SAN FRANCISCO BAY AREA .LOCATION....................JAN 14 SANTA ROSA.................21/1963 KENTFIELD..................25/1949 SAN RAFAEL.................28/2007 NAPA.......................24/1963 SAN FRANCISCO..............29/1888 SFO........................31/1963 OAKLAND....................33/2007 OAKLAND AIRPORT............28/2007 RICHMOND...................31/1955 LIVERMORE..................21/1963 MOUNTAIN VIEW..............28/2007 SAN JOSE...................28/1997 GILROY.....................19/1963 MONTEREY BAY AREA .LOCATION....................JAN 14 MONTEREY...................30/1997 SANTA CRUZ.................22/1963 SALINAS....................24/2007 SALINAS AIRPORT............25/2007 KING CITY..................17/2007 && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...FREEZE WARNING...INTERIOR VALLEYS OF THE SAN FRANCISCO AND MONTEREY BAY AREAS AND THE SANTA CRUZ/MONTEREY COASTLINE. && $$ PUBLIC FORECAST: STROBIN AVIATION/MARINE: MM CLIMATE: HENDERSON/BELL VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1045 AM EST MON JAN 14 2013 .UPDATE (REST OF TODAY THROUGH TUESDAY)... 15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A CONTINUED HIGHLY AMPLIFIED UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. PATTERN IS DOMINATED BY A LARGE AND IMPRESSIVE LONGWAVE TROUGH COVERING ALMOST THE ENTIRE CONUS. THE LAST DOMAIN OF THE ONCE PROMINENT UPPER RIDGE ALONG THE EAST COAST IS ACROSS THE FAR SOUTHEASTERN STATES. LUCKILY...THIS INCLUDES US AND WILL ALLOW OUR GENERALLY DRY AND WARM WEATHER TO CONTINUE FOR ANOTHER COUPLE OF DAYS. UPPER LEVEL JET AND HIGH LEVEL MOISTURE AXIS IS LOCATED WELL OFF TO OUR NORTHWEST TODAY...AND HENCE WE SHOULD SEE MUCH LESS IN THE WAY OF HIGH LEVEL CIRRUS COMPARED TO WHAT OCCURRED ON SUNDAY. HOWEVER...SIMILAR TO PREVIOUS DAYS...WE WILL SEE THE DEVELOPMENT OF A SCT-BKN SHALLOW CU FIELD WITHIN THE SOUTHEAST LOW LEVEL FLOW BY THE EARLY AFTERNOON HOURS. MORNING SOUNDINGS HAVE A VERY SIMILAR MID/LOW LEVEL PROFILE THE PAST FEW DAYS...AND THAT PATTERN CONTINUES THIS MORNING WITH A WELL-DEFINED SUBSIDENCE INVERSION AROUND 850MB UNDERNEATH THE SUPPRESSION OF THE UPPER RIDGE. EXPECT DIURNAL MIXING BY LATE AFTERNOON UP TO AROUND 5000 FEET AND WITH 850MB TEMPS IN THE 14-15C RANGE...THIS SHOULD MIX OUT NICELY TO HIGH TEMPS IN THE LOWER 80S AWAY FROM THE IMMEDIATE COAST. THE WEAK GRADIENT AND STRONG LAND BASED HEATING SHOULD BE ENOUGH TO TURN WINDS ONSHORE AT THE BEACHES DURING THE AFTERNOON WITH FEEBLE SEA-BREEZE DEVELOPMENT. MOST OF THE HIRES GUIDANCE IS SHOWING THIS WIND SHIFT BY 19-20Z...AND THIS SHOULD KEEP THE IMMEDIATE COAST A FEW DEGREES COOLER. MORE OF THE SAME FOR TONIGHT INTO TUESDAY AS THE STACKED RIDGING HOLDS ON JUST A LITTLE BIT LONGER. STATIC SYNOPTIC PATTERNS GENERALLY YIELD STATIC WEATHER. THIS FORECAST WILL REFLECT THAT PHILOSOPHY WITH SOME PATCHY FOG AND LOW CLOUDS DURING THE LATE NIGHT / EARLY MORNING HOURS OF TUESDAY...THEN HAVING ANY FOG BURN OFF BY AROUND 900 AM. AFTERNOON TEMPS WILL CLIMB TO WITHIN A FEW DEGREES OF 80 INLAND...AND A FEW DEGREES COOLER AT THE BEACHES WITH AN ONSHORE AFTERNOON BREEZE. ENJOY! && .AVIATION... MORNING FOG JUST ABOUT GONE WITH MAINLY VFR REST OF THE DAY. PATCHY FOG POSSIBLE AGAIN TONIGHT WITH MAIN IMPACTS EXPECTED AT PGD. && .MARINE... HIGH PRESSURE NORTH OF THE BAHAMAS WILL CONTINUE TO RIDGE BACK TO THE WEST ACROSS THE FLORIDA PENINSULA AND EASTERN GULF OF MEXICO THROUGH WEDNESDAY. A COLD FRONT WILL THEN CROSS THE FORECAST WATERS DURING THURSDAY WITH A WIND SHIFT TO THE NORTH IN ITS WAKE BY THURSDAY NIGHT AND FRIDAY. A PERIOD OF CAUTIONARY TO ADVISORY LEVEL WINDS AND SEAS WILL ALSO BE POSSIBLE IN THE WAKE OF THIS FRONT. && .PRELIMINARY POINT TEMPS/POPS... TPA 80 63 78 62 / 0 0 05 05 FMY 80 63 80 62 / 0 0 05 05 GIF 80 59 81 59 / 0 0 05 05 SRQ 78 60 77 61 / 0 0 05 05 BKV 81 53 81 55 / 0 0 05 05 SPG 78 64 76 65 / 0 0 05 05 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/MARINE...MROCZKA AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
645 AM EST MON JAN 14 2013 .AVIATION... /12 UTC TAFS/ ONLY MINOR CHNGS WRT LATEST TAFS. LEADING EDGE CLEARING SLOWING INVOF KSBN PER LAKE INFLUENCE...THOUGH CIGS SHOULD BE VFR/UNLIMITED BY ABOUT 14-1430 UTC AT KSBN AIRFIELD. END OF FUEL ALT CONDS MORE IMMINENT AT KFWA...WITH VFR CONDS ASSURED THROUGH THE END OF THE FCST PD. && .SHORT TERM... /TODAY THROUGH TUESDAY NIGHT/ NMRS MESOGAMMA THERMAL ROLLS CRNTLY BLOSSOMING WSR-88 VCP 31 RETURNS ERLY THIS MORNING...EXTNDG FARTHER SOUTH THAN TYPICAL LAKE RESPONSE...AT LEAST TO KRCR-WABASH LN. LK MSTR ENHANCEMENT RATHER MINIMAL GIVEN ONLY LWR TEENS LK/8H THERMAL DIFFERENTIAL ACRS FAR SRN LK MI. THIN LYR LIFT ON NOSE OF 30-35KT 8H JETLET/SHORTWAVE FM NRN IL AT 03 UTC. 8H PSUEDOFRONT APPEARS ORTHOGONALLY ALONG LEADING EDGE OF RAP ANALYZED THIN LYR NEAR SFC/950-900 MB/ FGEN ZONE LAID OUT SRN LK HUR-SERN FA-SRN IN...WHICH SHOULD QUELL FLURRIES MENTION BY ABOUT 14 UTC. THIS THE ONLY SENSIBLE WX IN THE SHORT TERM PD. THEREAFTER...THE DEEP SCOUR OF MSTR BY CP CANADIAN PLAINS AIRMASS TO CONT TO ERODE RMNG STRATOCU FIELD TDY ON LEADING EDGE OF 1034MB RIDGE. ANTICIPATE POOR THERMAL RECOVERY THOUGH IN LIGHT OF SIG AIRMASS EXCHANGE ALONG WITH POTNL INCRS IN CI/CS LTR THIS AFTN ASSOCD WITH INTENSE ULVL JETSTREAK ON ORDER OF 180-200 KTS LIFTG THROUGH MID MS VLY TO FAR SRN ONT THIS EVE. GOOD POTNL FOR DECOUPLED BLYR LATE TONIGHT. DOWN TO LWR TEENS/PSBLY LWR SINGLE DIGITS...SPCLY FAR WRN CWA WITH BEST DURATION FOR LONGWAVE LOSSES. SLIGHT SFC- 925MB THERMAL MODIFICATION BY DAYBREAK WED...ALONG WITH INCRSD MIXED BL...WITH CWA ON SERN PERIPHERY OF RAMPING FLOW ASSOCD WITH HIGH BELTED CLIPPER. && .LONG TERM... /WEDNESDAY THROUGH SUNDAY/ A LONGWAVE TROF WILL AMPLIFY OVER EASTERN NORTH AMERICA THIS PERIOD AS A PRECURSOR OF THE ARRIVAL OF VERY COLD AIR LATE IN THE PERIOD. THE 500 MB GFS AND CANADIAN ANALOGS...GFS AND CANADIAN ENSEMBLES AND THE ECMWF ALL SUPPORT THE ESTABLISHMENT OF A MUCH COLDER PATTERN EARLY NEXT WEEK. AHEAD OF THE AMPLIFYING UPPER TROF...A WEAKER TROF WILL MOVE ACROSS THE AREA ACCOMPANIED BY A COLD FRONT WEDNESDAY NIGHT. THERE IS NOT MUCH SUPPORT FOR PRECIPITATION WITH THIS SYSTEM INCLUDING LAKE EFFECT SNOW. MOISTURE IS LIMITED AND FORCING IS WEAK. THE MOST UNSTABLE LAKE EFFECT DELTA T VALUES BEFORE SUNDAY ARE 10 TO 14...BUT WITH AN UNFAVORABLE FETCH OVER MUCH OF THE PERIOD...KEPT THE FORECAST DRY. FOR LATE IN THE PERIOD...GUT FEELING HIGHS SUNDAY ARE TOO WARM. HOWEVER...LEFT HIGHS AROUND 30 MOST AREAS GIVEN THE UNCERTAINTY OF THE ARRIVAL TIME OF THE FRONT. THE GFS MEAN ENSEMBLE MOS HIGHS SUNDAY ARE 22 TO 27 WHICH MAY BE ON TRACK. A PERIOD OF LIGHT SNOW IN THE ARCTIC AIR MAY ALSO EVENTUALLY NEED TO BE ADDED TO THE FORECAST SUNDAY IF A FASTER FRONTAL PASSAGE PREVAILS. TEMPERATURES MAY BE STEADY OR SLOWING FALLING SUNDAY. FOR NOW...WENT WITH A SMALL DIURNAL RISE SUNDAY. && .MARINE... LOOK FOR RAPIDLY INCRSG GRADIENT FLOW AS ULVL TROF SHIFTS GRDLY EWD INTO WRN GRTLKS BY LATE TUE. MIDWEEK MARINE HEADLINES TO LATER FOCUS ON NEED FOR NEARSHORE GALE WATCH/WARNING WITH BEST WINDOW IN THE 12-21 UTC WED TIMEFRAME. ACCELERATION RATE OF FLOW SHOULD PRECLUDE LEAD IN SC.Y...THOUGH LATER FCSTS TO FINE TUNE AS NEED BE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046. && $$ SHORT TERM...MURPHY LONG TERM...SKIPPER AVIATION...MURPHY MARINE...MURPHY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
523 AM EST MON JAN 14 2013 .SHORT TERM... /TODAY THROUGH TUESDAY NIGHT/ NMRS MESOGAMMA THERMAL ROLLS CRNTLY BLOSSOMING WSR-88 VCP 31 RETURNS ERLY THIS MORNING...EXTNDG FARTHER SOUTH THAN TYPICAL LAKE RESPONSE...AT LEAST TO KRCR-WABASH LN. LK MSTR ENHANCEMENT RATHER MINIMAL GIVEN ONLY LWR TEENS LK/8H THERMAL DIFFERENTIAL ACRS FAR SRN LK MI. THIN LYR LIFT ON NOSE OF 30-35KT 8H JETLET/SHORTWAVE FM NRN IL AT 03 UTC. 8H PSUEDOFRONT APPEARS ORTHOGONALLY ALONG LEADING EDGE OF RAP ANALYZED THIN LYR NEAR SFC/950-900 MB/ FGEN ZONE LAID OUT SRN LK HUR-SERN FA-SRN IN...WHICH SHOULD QUELL FLURRIES MENTION BY ABOUT 14 UTC. THIS THE ONLY SENSIBLE WX IN THE SHORT TERM PD. THEREAFTER...THE DEEP SCOUR OF MSTR BY CP CANADIAN PLAINS AIRMASS TO CONT TO ERODE RMNG STRATOCU FIELD TDY ON LEADING EDGE OF 1034MB RIDGE. ANTICIPATE POOR THERMAL RECOVERY THOUGH IN LIGHT OF SIG AIRMASS EXCHANGE ALONG WITH POTNL INCRS IN CI/CS LTR THIS AFTN ASSOCD WITH INTENSE ULVL JETSTREAK ON ORDER OF 180-200 KTS LIFTG THROUGH MID MS VLY TO FAR SRN ONT THIS EVE. GOOD POTNL FOR DECOUPLED BLYR LATE TONIGHT. DOWN TO LWR TEENS/PSBLY LWR SINGLE DIGITS...SPCLY FAR WRN CWA WITH BEST DURATION FOR LONGWAVE LOSSES. SLIGHT SFC- 925MB THERMAL MODIFICATION BY DAYBREAK WED...ALONG WITH INCRSD MIXED BL...WITH CWA ON SERN PERIPHERY OF RAMPING FLOW ASSOCD WITH HIGH BELTED CLIPPER. && .LONG TERM... /WEDNESDAY THROUGH SUNDAY/ A LONGWAVE TROF WILL AMPLIFY OVER EASTERN NORTH AMERICA THIS PERIOD AS A PRECURSOR OF THE ARRIVAL OF VERY COLD AIR LATE IN THE PERIOD. THE 500 MB GFS AND CANADIAN ANALOGS...GFS AND CANADIAN ENSEMBLES AND THE ECMWF ALL SUPPORT THE ESTABLISHMENT OF A MUCH COLDER PATTERN EARLY NEXT WEEK. AHEAD OF THE AMPLIFYING UPPER TROF...A WEAKER TROF WILL MOVE ACROSS THE AREA ACCOMPANIED BY A COLD FRONT WEDNESDAY NIGHT. THERE IS NOT MUCH SUPPORT FOR PRECIPITATION WITH THIS SYSTEM INCLUDING LAKE EFFECT SNOW. MOISTURE IS LIMITED AND FORCING IS WEAK. THE MOST UNSTABLE LAKE EFFECT DELTA T VALUES BEFORE SUNDAY ARE 10 TO 14...BUT WITH AN UNFAVORABLE FETCH OVER MUCH OF THE PERIOD...KEPT THE FORECAST DRY. FOR LATE IN THE PERIOD...GUT FEELING HIGHS SUNDAY ARE TOO WARM. HOWEVER...LEFT HIGHS AROUND 30 MOST AREAS GIVEN THE UNCERTAINTY OF THE ARRIVAL TIME OF THE FRONT. THE GFS MEAN ENSEMBLE MOS HIGHS SUNDAY ARE 22 TO 27 WHICH MAY BE ON TRACK. A PERIOD OF LIGHT SNOW IN THE ARCTIC AIR MAY ALSO EVENTUALLY NEED TO BE ADDED TO THE FORECAST SUNDAY IF A FASTER FRONTAL PASSAGE PREVAILS. TEMPERATURES MAY BE STEADY OR SLOWING FALLING SUNDAY. FOR NOW...WENT WITH A SMALL DIURNAL RISE SUNDAY. && .AVIATION... /06 UTC TAFS/ INCRSD ENTRAINMENT OF DRIER AIR ACRS NRN IL/SRN WI CIRCUITOUSLY VIA LAND/AROUND SRN TIP OF LK MI AND INTO NRN IN. THIS SHOULD SUPPORT A MORE RAPID RECOVERY OUT OF FUEL ALT CONDS AT KSBN/AROUND 10 UTC. THIS APPROX SAME TIME AS KFWA WHERE LAKE INFLUENCE LACKS IN BACKED WRLY/CROSS SHORT LAKE AXIS FLOW. && .MARINE... LOOK FOR RAPIDLY INCRSG GRADIENT FLOW AS ULVL TROF SHIFTS GRDLY EWD INTO WRN GRTLKS BY LATE TUE. MIDWEEK MARINE HEADLINES TO LATER FOCUS ON NEED FOR NEARSHORE GALE WATCH/WARNING WITH BEST WINDOW IN THE 12-21 UTC WED TIMEFRAME. ACCELERATION RATE OF FLOW SHOULD PRECLUDE LEAD IN SC.Y...THOUGH LATER FCSTS TO FINE TUNE AS NEED BE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046. && $$ SHORT TERM...MURPHY LONG TERM...SKIPPER AVIATION...MURPHY MARINE...MURPHY
AREA FORECAST DISCUSSION
NWS CARIBOU ME
903 AM EST MON JAN 14 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION BY AFTERNOON. MUCH COLDER TEMPERATURES ARE EXPECTED BEHIND THE FRONT FOR TONIGHT AND TUESDAY. AFTER A BRIEF RESPITE WEDNESDAY...AN ARCTIC FRONT WILL CROSS THE REGION THURSDAY AND BRING BITTERLY COLD AIR FOR LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... 900 AM UPDATE...ADDED NORTHERN 1/2 OF THE CWA IN A DENSE FOG ADVISORY THROUGH 11 AM. THIS WILL BE MAINLY ACROSS THE HIGHER TERRAIN. THE CANADIAN GEM DOING A FINE JOB IN PICKING THE FOG UP AS WELL AS THE RUC THIS MORNING IN THESE AREAS. DEWPOINTS RISING ALLOW FOR SOME MELTING OF THE SNOWPACK W/SSE WINDS ACROSS THE NORTH ALLOWING FOR DENSE FOG. ACROSS THE CENTRAL AND DOWNEAST AREAS, THE FOG IS BEGINNING TO LIFT W/VSBYS IMPROVING, SO ADJUSTMENTS HAVE BEEN MADE AND THE DENSE FOG ADVISORY HAS BEEN ALLOWED TO EXPIRE. SUNSHINE LATER THIS MORNING INT THE AFTERNOON WILL ALLOW FOR TEMPERATURES IN THESE AREAS TO WARM IN THE UPPER 40S TO POSSIBLY 50 DEGREES. WE WILL ASSESS MENTIONED IN THE PREVIOUS DISCUSSION...RAIN SHOWERS HAVE INDEED BEGUN MOVING INTO CENTRAL AND SOUTHERN PORTIONS OF THE FORECAST AREA. HAVE INCREASED POPS TO LIKELY IN THESE AREAS. NO OTHER CHANGES NEEDED. PREVIOUS DISCUSSION...WIDESPREAD FOG WILL CONTINUE THROUGH THE EARLY MORNING HOURS AS MOIST SOUTHWEST FLOW STREAMS INTO THE FORECAST AREA AHEAD OF AN APPROACHING COLD FRONT. WITH VISIBILITY STILL AT OR BELOW ONE HALF MILE, THE DENSE FOG ADVISORY REMAINS IN PLACE UNTIL 8 AM FOR DOWNEAST AREAS. UPSTREAM RADARS SHOW RAIN ASSOCIATED WITH THE FRONT CURRENTLY MOVING INTO NEW YORK. THIS PRECIPITATION WILL CONTINUE TO PUSH EASTWARD ALONG WITH THE FRONT, ENTERING NORTHWESTERN MAINE BY AROUND DAYBREAK. THE FRONT WILL CROSS THE AREA DURING THE MORNING HOURS, MOVING OFFSHORE BY EARLY AFTERNOON. THEREFORE EXPECT THE RAIN WILL QUICKLY COME TO AN END SHORTLY AFTER NOON. WHILE THE BULK OF THE PRECIPITATION WILL BE OVER NORTHERN PORTIONS OF THE FORECAST AREA, HAVE NOTED THAT SOME OF THE LATEST GUIDANCE, INCLUDING THE 3KM HRRR MODEL, INDICATES THAT THE RAIN WILL HOLD TOGETHER OVER DOWNEAST MAINE AS WELL. HAVE THEREFORE BUMPED UP POPS THERE A BIT THROUGH MID-MORNING, BUT THEY MAY HAVE TO BE INCREASED LATER AS TRENDS BECOME ESTABLISHED. TEMPERATURES WILL RISE SLIGHTLY THIS MORNING WITH HIGHS RANGING FROM THE LOWER 40S IN THE NORTH AND WEST TO MID AND UPPER 40S DOWNEAST. ONCE THE FRONT COMES THROUGH, TEMPERATURES WILL QUICKLY DROP UNDER BRISK NORTHWEST WINDS. HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION TONIGHT. EXPECT CLEARING SKIES AND DECREASING WINDS. ALTHOUGH OVERNIGHT TEMPS WILL REMAIN ABOVE NORMAL, IT WILL BE MUCH COLDER THAN READINGS OVER THE PAST COUPLE OF NIGHTS. LOWS WILL RANGE FROM THE SINGLE DIGITS IN THE NORTH TO THE UPPER TEENS DOWNEAST. COASTAL AREAS WILL REMAIN IN THE LOWER 20S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... FAIR AND COLDER CONDITIONS IS XPCTD TUE INTO TUE NGT AS SEMI- ARCTIC SFC HI PRES CROSSES THE REGION. RETURN SRLY FLOW WILL OCCUR ON WED BEHIND THIS HI AS IT MOVES INTO THE MARITIMES. IN THE MEANTIME... A FLAT S/WV TRACKING ENE FROM SE NEW ENG S OF THE GULF OF ME WILL BRING DOWNEAST PTNS OF THE FA INCREASING CLDS WED WITH A CHC OF LGT RN/SN LATE WED INTO WED EVE ALG THE COAST AND MSLY OVR THE ADJACENT COASTAL WATERS. IMMEDIATELY FOLLOWING THIS SYSTEM....A STRONG ARCTIC FRONT WILL APCH WRN PTNS OF THE FA LATE WED NGT WITH SOME CLDNSS AND A CHC OF SN SHWRS. TEMPS WILL BE A LITTLE MILDER ON WED AND WED NGT WITH THE RETURN SRLY FLOW THAN TUE AND TUE NGT WHICH WILL FEATURE NEAR SEASONAL TEMPS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... LONGER RANGE MODELS GENERALLY AGREE WITH MINOR TMG DIFFERENCES THAT THE ARCTIC FRONT WILL CROSS THE REGION THU MORN...WITH MOST OF SCT SN SHWRS OVR NW AND FAR NE PTNS OF THE REGION DURING THE PASSAGE OF THE FRONT. MUCH COLDER TEMPS FOLLOW FOR THU NGT THRU FRI NGT...WITH HI TEMPS WE SHOW FRI ACROSS THE REGION LIKELY OPTIMISTIC. HI CLDS COULD BEGIN INCREASING ACROSS OUR REGION FROM AN ADVCG S/WV FROM THE GREAT LKS AS EARLY AS LATE FRI NGT...BUT WILL LIKELY HOLD OFF UNTIL SAT. THE 00Z DTMNSTC GFS AND ECMWF CAME INTO BETTER AGREEMENT WITH THE TMG OF THE GREAT LKS S/WV...BRINGING OVRRNG SNFL TO THE FA...SPCLY NRN PTNS SAT NGT INTO SUN. OF THE TWO MODELS...THE GFS ACTUALLY BRINGS SIG QPF ACROSS THE N HLF OF THE REGION WITH THIS SYSTEM AS THE SFC TRACKS OVR OR JUST N OF THE FA...WITH LESSER AMTS SHOWN BY THE ECMWF. FOR NOW...WE WILL INCREASE POPS TO HI CHC FOR STRATIFORM SN UP TO 50 PERCENT FOR THE N....WITH LESSER POPS CNTRL AND DOWNEAST AREAS. ANY STEADY SN SHOULD WIND DOWN AS SN SHWRS SUN AFTN AND SUN NGT BEHIND THIS LOW AS IT MOVES INTO THE CAN MARITIMES...WITH POTENTIALLY ANOTHER SHOT OF BITTERLY COLD ARCTIC AIR ADVCTG INTO THE REGION BY LATE SUN NGT INTO MON. WE DO NOT INDICATE THE POTENTIAL MAGNITUDE OF THIS AIR MASS WITH REGARD TO TEMPS SUN NGT ATTM DUE TO UNCERTAINTY DUE TO PREVIOUS TMG DIFFERENCES BETWEEN LONGER RANGE MODELS IN PAST MODEL RUNS...BUT AS WE GET CLOSER TO THIS EVENT...MORE REALISTIC TEMPS WILL BE SHOWN. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... NEAR TERM: WIDESPREAD IFR WILL CONTINUE THROUGH AT LEAST 13Z-14Z. WHILE FOG MAY LIFT SOMEWHAT TOWARD DAYBREAK, RAIN ASSOCIATED WITH A COLD FRONT WILL KEEP CEILINGS IN THE IFR CATEGORY INTO MID- MORNING. CONDITIONS WILL GRADUALLY IMPROVE THEREAFTER, WITH ALL SITES REACHING VFR STATUS 18Z-20Z. SHORT TO LONG TERM: VFR XPCTD...XCPT BRIEF MVFR CONDITIONS POSSIBLE WITH SN SHWRS ACROSS NRN TAF SITES JUST AHEAD AND DURG THE PASSAGE OF AN ARCTIC COLD FRONT LATE WED NGT AND THU MORN. && .MARINE... NEAR TERM: SCA REMAINS IN EFFECT TODAY INTO TONIGHT. A COLD FRONT WILL MOVE ACROSS THE WATERS LATE THIS MORNING, TURNING SOUTHWEST WINDS 15 TO 20 KT TO THE NORTHWEST AND INCREASING THEM TO 20 TO 30 KT. THE WINDS WILL SUBSIDE LATER TONIGHT ONCE THE INITIAL COLD ADVECTION HAS PASSED. SHORT TO LONG TERM: INITIALLY NO HDLNS TUE INTO WED MORN...THEN WINDS AND SEAS APCHG AND REACHING SCA CONDITIONS FOR WED AFTN INTO THUS MORN AHEAD TO JUST BEHIND THE ARCTIC COLD FRONT. CONDITIONS LOWER BLO SCA CONDITIONS LATER THU INTO THU NGT AND CONT INTO FRI. KEPT CLOSE TO FCST WW3 GUIDANCE FOR WV HTS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR MEZ001>006. MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ050>052. && $$ NEAR TERM...HASTINGS/HEWITT SHORT TERM...VJN LONG TERM...VJN AVIATION...HASTINGS/HEWITT MARINE...HASTINGS/HEWITT/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
742 AM EST MON JAN 14 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION BY AFTERNOON. MUCH COLDER TEMPERATURES ARE EXPECTED BEHIND THE FRONT FOR TONIGHT AND TUESDAY. AFTER A BRIEF RESPITE WEDNESDAY...AN ARCTIC FRONT WILL CROSS THE REGION THURSDAY AND BRING BITTERLY COLD AIR FOR LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... 520 AM UPDATE...AS MENTIONED IN THE PREVIOUS DISCUSSION...RAIN SHOWERS HAVE INDEED BEGUN MOVING INTO CENTRAL AND SOUTHERN PORTIONS OF THE FORECAST AREA. HAVE INCREASED POPS TO LIKELY IN THESE AREAS. NO OTHER CHANGES NEEDED. PREVIOUS DISCUSSION...WIDESPREAD FOG WILL CONTINUE THROUGH THE EARLY MORNING HOURS AS MOIST SOUTHWEST FLOW STREAMS INTO THE FORECAST AREA AHEAD OF AN APPROACHING COLD FRONT. WITH VISIBILITY STILL AT OR BELOW ONE HALF MILE, THE DENSE FOG ADVISORY REMAINS IN PLACE UNTIL 8 AM FOR DOWNEAST AREAS. UPSTREAM RADARS SHOW RAIN ASSOCIATED WITH THE FRONT CURRENTLY MOVING INTO NEW YORK. THIS PRECIPITATION WILL CONTINUE TO PUSH EASTWARD ALONG WITH THE FRONT, ENTERING NORTHWESTERN MAINE BY AROUND DAYBREAK. THE FRONT WILL CROSS THE AREA DURING THE MORNING HOURS, MOVING OFFSHORE BY EARLY AFTERNOON. THEREFORE EXPECT THE RAIN WILL QUICKLY COME TO AN END SHORTLY AFTER NOON. WHILE THE BULK OF THE PRECIPITATION WILL BE OVER NORTHERN PORTIONS OF THE FORECAST AREA, HAVE NOTED THAT SOME OF THE LATEST GUIDANCE, INCLUDING THE 3KM HRRR MODEL, INDICATES THAT THE RAIN WILL HOLD TOGETHER OVER DOWNEAST MAINE AS WELL. HAVE THEREFORE BUMPED UP POPS THERE A BIT THROUGH MID-MORNING, BUT THEY MAY HAVE TO BE INCREASED LATER AS TRENDS BECOME ESTABLISHED. TEMPERATURES WILL RISE SLIGHTLY THIS MORNING WITH HIGHS RANGING FROM THE LOWER 40S IN THE NORTH AND WEST TO MID AND UPPER 40S DOWNEAST. ONCE THE FRONT COMES THROUGH, TEMPERATURES WILL QUICKLY DROP UNDER BRISK NORTHWEST WINDS. HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION TONIGHT. EXPECT CLEARING SKIES AND DECREASING WINDS. ALTHOUGH OVERNIGHT TEMPS WILL REMAIN ABOVE NORMAL, IT WILL BE MUCH COLDER THAN READINGS OVER THE PAST COUPLE OF NIGHTS. LOWS WILL RANGE FROM THE SINGLE DIGITS IN THE NORTH TO THE UPPER TEENS DOWNEAST. COASTAL AREAS WILL REMAIN IN THE LOWER 20S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... FAIR AND COLDER CONDITIONS IS XPCTD TUE INTO TUE NGT AS SEMI- ARCTIC SFC HI PRES CROSSES THE REGION. RETURN SRLY FLOW WILL OCCUR ON WED BEHIND THIS HI AS IT MOVES INTO THE MARITIMES. IN THE MEANTIME... A FLAT S/WV TRACKING ENE FROM SE NEW ENG S OF THE GULF OF ME WILL BRING DOWNEAST PTNS OF THE FA INCREASING CLDS WED WITH A CHC OF LGT RN/SN LATE WED INTO WED EVE ALG THE COAST AND MSLY OVR THE ADJACENT COASTAL WATERS. IMMEDIATELY FOLLOWING THIS SYSTEM....A STRONG ARCTIC FRONT WILL APCH WRN PTNS OF THE FA LATE WED NGT WITH SOME CLDNSS AND A CHC OF SN SHWRS. TEMPS WILL BE A LITTLE MILDER ON WED AND WED NGT WITH THE RETURN SRLY FLOW THAN TUE AND TUE NGT WHICH WILL FEATURE NEAR SEASONAL TEMPS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... LONGER RANGE MODELS GENERALLY AGREE WITH MINOR TMG DIFFERENCES THAT THE ARCTIC FRONT WILL CROSS THE REGION THU MORN...WITH MOST OF SCT SN SHWRS OVR NW AND FAR NE PTNS OF THE REGION DURING THE PASSAGE OF THE FRONT. MUCH COLDER TEMPS FOLLOW FOR THU NGT THRU FRI NGT...WITH HI TEMPS WE SHOW FRI ACROSS THE REGION LIKELY OPTIMISTIC. HI CLDS COULD BEGIN INCREASING ACROSS OUR REGION FROM AN ADVCG S/WV FROM THE GREAT LKS AS EARLY AS LATE FRI NGT...BUT WILL LIKELY HOLD OFF UNTIL SAT. THE 00Z DTMNSTC GFS AND ECMWF CAME INTO BETTER AGREEMENT WITH THE TMG OF THE GREAT LKS S/WV...BRINGING OVRRNG SNFL TO THE FA...SPCLY NRN PTNS SAT NGT INTO SUN. OF THE TWO MODELS...THE GFS ACTUALLY BRINGS SIG QPF ACROSS THE N HLF OF THE REGION WITH THIS SYSTEM AS THE SFC TRACKS OVR OR JUST N OF THE FA...WITH LESSER AMTS SHOWN BY THE ECMWF. FOR NOW...WE WILL INCREASE POPS TO HI CHC FOR STRATIFORM SN UP TO 50 PERCENT FOR THE N....WITH LESSER POPS CNTRL AND DOWNEAST AREAS. ANY STEADY SN SHOULD WIND DOWN AS SN SHWRS SUN AFTN AND SUN NGT BEHIND THIS LOW AS IT MOVES INTO THE CAN MARITIMES...WITH POTENTIALLY ANOTHER SHOT OF BITTERLY COLD ARCTIC AIR ADVCTG INTO THE REGION BY LATE SUN NGT INTO MON. WE DO NOT INDICATE THE POTENTIAL MAGNITUDE OF THIS AIR MASS WITH REGARD TO TEMPS SUN NGT ATTM DUE TO UNCERTAINTY DUE TO PREVIOUS TMG DIFFERENCES BETWEEN LONGER RANGE MODELS IN PAST MODEL RUNS...BUT AS WE GET CLOSER TO THIS EVENT...MORE REALISTIC TEMPS WILL BE SHOWN. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... NEAR TERM: WIDESPREAD IFR WILL CONTINUE THROUGH AT LEAST 13Z-14Z. WHILE FOG MAY LIFT SOMEWHAT TOWARD DAYBREAK, RAIN ASSOCIATED WITH A COLD FRONT WILL KEEP CEILINGS IN THE IFR CATEGORY INTO MID- MORNING. CONDITIONS WILL GRADUALLY IMPROVE THEREAFTER, WITH ALL SITES REACHING VFR STATUS 18Z-20Z. SHORT TO LONG TERM: VFR XPCTD...XCPT BRIEF MVFR CONDITIONS POSSIBLE WITH SN SHWRS ACROSS NRN TAF SITES JUST AHEAD AND DURG THE PASSAGE OF AN ARCTIC COLD FRONT LATE WED NGT AND THU MORN. && .MARINE... NEAR TERM: SCA REMAINS IN EFFECT TODAY INTO TONIGHT. A COLD FRONT WILL MOVE ACROSS THE WATERS LATE THIS MORNING, TURNING SOUTHWEST WINDS 15 TO 20 KT TO THE NORTHWEST AND INCREASING THEM TO 20 TO 30 KT. THE WINDS WILL SUBSIDE LATER TONIGHT ONCE THE INITIAL COLD ADVECTION HAS PASSED. SHORT TO LONG TERM: INITIALLY NO HDLNS TUE INTO WED MORN...THEN WINDS AND SEAS APCHG AND REACHING SCA CONDITIONS FOR WED AFTN INTO THUS MORN AHEAD TO JUST BEHIND THE ARCTIC COLD FRONT. CONDITIONS LOWER BLO SCA CONDITIONS LATER THU INTO THU NGT AND CONT INTO FRI. KEPT CLOSE TO FCST WW3 GUIDANCE FOR WV HTS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR MEZ011- 015>017-029>032. MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ050>052. && $$ NEAR TERM...HASTINGS SHORT TERM...VJN LONG TERM...VJN AVIATION...HASTINGS MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
521 AM EST MON JAN 14 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION BY AFTERNOON. MUCH COLDER TEMPERATURES ARE EXPECTED BEHIND THE FRONT FOR TONIGHT AND TUESDAY. AFTER A BRIEF RESPITE WEDNESDAY...AN ARCTIC FRONT WILL CROSS THE REGION THURSDAY AND BRING BITTERLY COLD AIR FOR LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... 520 AM UPDATE...AS MENTIONED IN THE PREVIOUS DISCUSSION...RAIN SHOWERS HAVE INDEED BEGUN MOVING INTO CENTRAL AND SOUTHERN PORTIONS OF THE FORECAST AREA. HAVE INCREASED POPS TO LIKELY IN THESE AREAS. NO OTHER CHANGES NEEDED. PREVIOUS DISCUSSION...WIDESPREAD FOG WILL CONTINUE THROUGH THE EARLY MORNING HOURS AS MOIST SOUTHWEST FLOW STREAMS INTO THE FORECAST AREA AHEAD OF AN APPROACHING COLD FRONT. WITH VISIBILITY STILL AT OR BELOW ONE HALF MILE, THE DENSE FOG ADVISORY REMAINS IN PLACE UNTIL 8 AM FOR DOWNEAST AREAS. UPSTREAM RADARS SHOW RAIN ASSOCIATED WITH THE FRONT CURRENTLY MOVING INTO NEW YORK. THIS PRECIPITATION WILL CONTINUE TO PUSH EASTWARD ALONG WITH THE FRONT, ENTERING NORTHWESTERN MAINE BY AROUND DAYBREAK. THE FRONT WILL CROSS THE AREA DURING THE MORNING HOURS, MOVING OFFSHORE BY EARLY AFTERNOON. THEREFORE EXPECT THE RAIN WILL QUICKLY COME TO AN END SHORTLY AFTER NOON. WHILE THE BULK OF THE PRECIPITATION WILL BE OVER NORTHERN PORTIONS OF THE FORECAST AREA, HAVE NOTED THAT SOME OF THE LATEST GUIDANCE, INCLUDING THE 3KM HRRR MODEL, INDICATES THAT THE RAIN WILL HOLD TOGETHER OVER DOWNEAST MAINE AS WELL. HAVE THEREFORE BUMPED UP POPS THERE A BIT THROUGH MID-MORNING, BUT THEY MAY HAVE TO BE INCREASED LATER AS TRENDS BECOME ESTABLISHED. TEMPERATURES WILL RISE SLIGHTLY THIS MORNING WITH HIGHS RANGING FROM THE LOWER 40S IN THE NORTH AND WEST TO MID AND UPPER 40S DOWNEAST. ONCE THE FRONT COMES THROUGH, TEMPERATURES WILL QUICKLY DROP UNDER BRISK NORTHWEST WINDS. HIGH PRESSURE WILL SLOWLY BUILD OVER THE REGION TONIGHT. EXPECT CLEARING SKIES AND DECREASING WINDS. ALTHOUGH OVERNIGHT TEMPS WILL REMAIN ABOVE NORMAL, IT WILL BE MUCH COLDER THAN READINGS OVER THE PAST COUPLE OF NIGHTS. LOWS WILL RANGE FROM THE SINGLE DIGITS IN THE NORTH TO THE UPPER TEENS DOWNEAST. COASTAL AREAS WILL REMAIN IN THE LOWER 20S. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... FAIR AND COLDER CONDITIONS IS XPCTD TUE INTO TUE NGT AS SEMI- ARCTIC SFC HI PRES CROSSES THE REGION. RETURN SRLY FLOW WILL OCCUR ON WED BEHIND THIS HI AS IT MOVES INTO THE MARITIMES. IN THE MEANTIME... A FLAT S/WV TRACKING ENE FROM SE NEW ENG S OF THE GULF OF ME WILL BRING DOWNEAST PTNS OF THE FA INCREASING CLDS WED WITH A CHC OF LGT RN/SN LATE WED INTO WED EVE ALG THE COAST AND MSLY OVR THE ADJACENT COASTAL WATERS. IMMEDIATELY FOLLOWING THIS SYSTEM....A STRONG ARCTIC FRONT WILL APCH WRN PTNS OF THE FA LATE WED NGT WITH SOME CLDNSS AND A CHC OF SN SHWRS. TEMPS WILL BE A LITTLE MILDER ON WED AND WED NGT WITH THE RETURN SRLY FLOW THAN TUE AND TUE NGT WHICH WILL FEATURE NEAR SEASONAL TEMPS. && .LONG TERM /THURSDAY THROUGH SUNDAY/... LONGER RANGE MODELS GENERALLY AGREE WITH MINOR TMG DIFFERENCES THAT THE ARCTIC FRONT WILL CROSS THE REGION THU MORN...WITH MOST OF SCT SN SHWRS OVR NW AND FAR NE PTNS OF THE REGION DURING THE PASSAGE OF THE FRONT. MUCH COLDER TEMPS FOLLOW FOR THU NGT THRU FRI NGT...WITH HI TEMPS WE SHOW FRI ACROSS THE REGION LIKELY OPTIMISTIC. HI CLDS COULD BEGIN INCREASING ACROSS OUR REGION FROM AN ADVCG S/WV FROM THE GREAT LKS AS EARLY AS LATE FRI NGT...BUT WILL LIKELY HOLD OFF UNTIL SAT. THE 00Z DTMNSTC GFS AND ECMWF CAME INTO BETTER AGREEMENT WITH THE TMG OF THE GREAT LKS S/WV...BRINGING OVRRNG SNFL TO THE FA...SPCLY NRN PTNS SAT NGT INTO SUN. OF THE TWO MODELS...THE GFS ACTUALLY BRINGS SIG QPF ACROSS THE N HLF OF THE REGION WITH THIS SYSTEM AS THE SFC TRACKS OVR OR JUST N OF THE FA...WITH LESSER AMTS SHOWN BY THE ECMWF. FOR NOW...WE WILL INCREASE POPS TO HI CHC FOR STRATIFORM SN UP TO 50 PERCENT FOR THE N....WITH LESSER POPS CNTRL AND DOWNEAST AREAS. ANY STEADY SN SHOULD WIND DOWN AS SN SHWRS SUN AFTN AND SUN NGT BEHIND THIS LOW AS IT MOVES INTO THE CAN MARITIMES...WITH POTENTIALLY ANOTHER SHOT OF BITTERLY COLD ARCTIC AIR ADVCTG INTO THE REGION BY LATE SUN NGT INTO MON. WE DO NOT INDICATE THE POTENTIAL MAGNITUDE OF THIS AIR MASS WITH REGARD TO TEMPS SUN NGT ATTM DUE TO UNCERTAINTY DUE TO PREVIOUS TMG DIFFERENCES BETWEEN LONGER RANGE MODELS IN PAST MODEL RUNS...BUT AS WE GET CLOSER TO THIS EVENT...MORE REALISTIC TEMPS WILL BE SHOWN. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... NEAR TERM: WIDESPREAD IFR WILL CONTINUE THROUGH AT LEAST 13Z-14Z. WHILE FOG MAY LIFT SOMEWHAT TOWARD DAYBREAK, RAIN ASSOCIATED WITH A COLD FRONT WILL KEEP CEILINGS IN THE IFR CATEGORY INTO MID- MORNING. CONDITIONS WILL GRADUALLY IMPROVE THEREAFTER, WITH ALL SITES REACHING VFR STATUS 18Z-20Z. SHORT TO LONG TERM: VFR XPCTD...XCPT BRIEF MVFR CONDITIONS POSSIBLE WITH SN SHWRS ACROSS NRN TAF SITES JUST AHEAD AND DURG THE PASSAGE OF AN ARCTIC COLD FRONT LATE WED NGT AND THU MORN. && .MARINE... NEAR TERM: SCA REMAINS IN EFFECT TODAY INTO TONIGHT. A COLD FRONT WILL MOVE ACROSS THE WATERS LATE THIS MORNING, TURNING SOUTHWEST WINDS 15 TO 20 KT TO THE NORTHWEST AND INCREASING THEM TO 20 TO 30 KT. THE WINDS WILL SUBSIDE LATER TONIGHT ONCE THE INITIAL COLD ADVECTION HAS PASSED. SHORT TO LONG TERM: INITIALLY NO HDLNS TUE INTO WED MORN...THEN WINDS AND SEAS APCHG AND REACHING SCA CONDITIONS FOR WED AFTN INTO THUS MORN AHEAD TO JUST BEHIND THE ARCTIC COLD FRONT. CONDITIONS LOWER BLO SCA CONDITIONS LATER THU INTO THU NGT AND CONT INTO FRI. KEPT CLOSE TO FCST WW3 GUIDANCE FOR WV HTS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR MEZ011- 015>017-029>032. MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ050>052. && $$ NEAR TERM...HASTINGS SHORT TERM...VJN LONG TERM...VJN AVIATION...HASTINGS MARINE...HASTINGS/VJN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
652 AM EST MON JAN 14 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 535 AM EST MON JAN 14 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH EXTENDING FROM HUDSON BAY THROUGH THE NRN PLAINS INTO THE SW CONUS. THE SHORTWAVE TROUGH THAT BROUGHT -SN/FLURRIES TO UPPER MI AND HELPED ENHANCED THE LES INTO THE WEST HAD LIFTED OFF TO THE NORTHEAST TOWARD QUEBEC. IN ITS WAKE...SHRTWV RIDGING WITH QVECTOR DIV AND SUBSIDENCE HAS HELPED LIMIT LES INTENSITY OVERNIGHT. UPSTREAM...ONLY A WEAK SHRTWV WAS NOTED OVER NEBRASKA. AT THE SFC...A RIDGE EXTENDED FROM SASK THROUGH THE NRN PLAINS INTO THE MID MS VALLEY RESULTING IN W TO WNW FLOW THROUGH THE NRN GREAT LAKES. THE LINGERING LAKE INDUCED TROUGH HAS KEPT THE FOCUS OF LES OVER THE KEWEENAW AND FOR LOCATIONS EAST OF P53. INSTABILITY FOR LES WILL REMAIN FAVORABLE WITH 850 MB TEMPS NEAR -19C PRODUCING LAKE INDUCED CAPES IN THE 400-500 J/KG RANGE. THE DGZ WILL ALSO REMAIN IN THE CONVECTIVE LAYER...LEADING TO HIGH SNOW/WATER RATIOS IN THE 25/1 TO 30/1 RANGE. UPSTREAM LOW LEVEL MOISTURE OVER NRN MN WILL HELP MAINTAIN LES ACROSS WRN LAKE SUPERIOR. MODELS WERE CONSISTENT IN SUGGESTING THAT LOW LEVEL WINDS WILL SLOWLY BACK. AS A RESULT...THE LES INTO THE ERN CWA COULD PRODUCE AN ADDITIONAL 1 TO 3 INCHES BEFORE THE BANDS GRADUALLY SHIFT TOWARD THE SHORELINE AND MOVE OUT OF THE AREA THIS AFTERNOON. OVER THE WEST... THE HIGHER RES MODELS SUGGEST THAT THE STRONGEST LES BAND(S) MAINLY NEAR THE SHORELINE OF ONTONAGON COUNTY TOWARD TWIN LAKES THIS MORNING WOULD GRADUALLY SHIFT THROUGH NRN HOUGHTON COUNTY TODAY AND EVENTUALLY TO CMX-P59 TONIGHT. THERE IS LOWER CONFIDENCE WITH THE SNOWFALL RATES AND AMOUNT OF TIME IT WILL LINGER OVER ANY GIVEN AREA. THE POTENTIAL REMAINS FOR LOCAL AMOUNTS IN THE 4 TO 8 INCH RANGE BOTH TODAY AND TONIGHT AS IT LIFTS THROUGH THESE AREAS. SO...THE LES WARNING WILL CONTINUE AT LEAST UNTIL 12Z/TUE. OVER THE REST OF THE CWA...EXPECT MAINLY JUST A FEW FLURRIES OVER THE NORTH OUTSIDE OF THE MAIN LES AREA. EVEN WITH MORE SUNSHINE TODAY OVER THE SOUTH...TEMPERATURES WILL REMAIN AT OR BELOW NORMAL FROM 12 TO 17 WEST AND IN THE LOWER 20S EAST. THERE MAY ALSO BE ENOUGH CLEARING TONIGHT INLAND WITH LIGHT WSW WINDS AS THE RIDGE BUILDS TOWARD THE REGION TO ALLOW TEMPS TO DIP TO AROUND ZERO. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 535 AM EST MON JAN 14 2013 TUESDAY LOOKS TO BE ONE OF THE FEW BREAKS FROM SNOW FOR MUCH OF THE LAND CWA...AS WINDS BACK TO THE WEST-SOUTHWEST AHEAD OF AN APPROACHING SHORTWAVE AND ASSOCIATED COLD FRONT. THIS WILL PUSH WHAT IS LEFT OF THE BANDS CURRENTLY OVER NORTHERN HOUGHTON AND KEWEENAW COUNTIES ALONG THE WESTERN SHORELINE DURING THE MORNING AND THEN OFFSHORE DURING THE AFTERNOON. THE BANDS WILL ALSO BE DIMINISHING IN INTENSITY DUE TO INCREASING H850 TEMPS. ELSEWHERE...LOOKS TO BE A FAIRLY NICE DAY WITH ONLY A FEW MID LEVEL CLOUDS MOVING THROUGH. HEADING INTO TUESDAY NIGHT...LOOKS LIKE IT COULD BE GUSTY ACROSS MUCH OF UPPER MICHIGAN AHEAD OF THE COLD FRONT. GALES OVER LAKE SUPERIOR STILL LOOK LIKELY...SO WILL CONTINUE GALE WATCH. OVER LAND...INVERSION WILL KEEP MUCH OF THE STRONG 50-60KT LOW LEVEL JET ALOFT. BUT LATE IN THE NIGHT...THINK IT WILL GET A LITTLE GUSTY AS THE 10-14MB 6HR PRESSURE FALLS MOVE ACROSS THE CWA. STRONGEST WINDS WILL LIKELY END UP IN THE SOUTHWEST WIND DOWNSLOPE AREAS NEAR LAKE SUPERIOR...MAYBE APPROACHING 35-45MPH...WHILE THE REST OF THE AREA WILL SEE A FEW HOUR PERIOD OF 25-35MPH GUSTS. THERE IS MUCH BETTER AGREEMENT WITH THE SHORTWAVE AND ASSOCIATED COLD FRONT THAT MOVES THROUGH LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DUE TO THIS...HAVE DELAYED THE START OF THE SNOW INTO THE OVERNIGHT HOURS. BEST H500 HEIGHT FALLS STAY OVER NORTHERN LAKE SUPERIOR AND SOUTHERN ONTARIO...BUT DECENT H850-500 Q-VECTOR CONVERGENCE MOVES OVER THE NORTHERN HALF OF THE CWA. WILL CONTINUE TO HIGHLIGHT THE HIGHEST POPS OVER THE NORTH HALF OF THE CWA...WITH CHANCES ELSEWHERE. WITH IT MOVING THROUGH FAIRLY QUICKLY...DON/T THINK THERE WILL BE TOO MUCH SNOW ACCUMULATION...WITH THE HIGHEST AMOUNTS OVER THE KEWEENAW AND LUCE COUNTY WHERE THERE COULD BE SOME ENHANCEMENT OFF LAKE MICHIGAN. THE LEAST AMOUNTS WILL LIKELY BE OVER THE CENTRAL CWA...WHERE DRY LOW LEVEL AIR WILL LEAD TO SOME INITIAL EVAPORATION OF THE SNOW. THERE IS A SLIGHT DELAY IN THE COLD AIR SURGING IN BEHIND THE FRONT...SO AFTER SNOW DIMINISHES ON WEDNESDAY MORNING AND EARLY AFTERNOON...PROBABLY WONT BE MUCH GOING ON LAKE EFFECT WISE UNTIL THE COLDER ARRIVES LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. BEHIND THE FRONT...PERSISTENT LAKE EFFECT SNOW IS EXPECTED WEDNESDAY NIGHT THROUGH THURSDAY NIGHT FOR WEST TO NORTHWEST FLOW FAVORED LOCATIONS. THE AREA WILL BE BETWEEN THE SURFACE LOW ROTATING OVER HUDSON BAY AND A HIGH PRESSURE IN THE PLAINS STATES. H850 TEMPS FALLING TO AROUND -24C BEHIND THE FRONT SHOULD PRODUCE SIGNIFICANT LAKE INSTABILITY DUE TO LAKE SUPERIOR WATER TEMPS AROUND 3C. SINCE MODELS ARE SHOWING THE INVERSION AROUND 5KFT TO BE FAIRLY WEAK...LAKE INDUCED EQL LEVELS RISE TO 9-10KFT AND CAPE VALUES APPROACH 900 J/KG. THESE ARE FAIRLY IMPRESSIVE VALUES...BUT THE CONCERN WITH SIGNIFICANT SNOWFALL COMES WITH THE BEST MOISTURE FOCUSED IN THE 2-5KFT RANGE. WITH THE COLD AIR...THE CONVECTIVE PORTION OF THE LAKE EFFECT SHOULD BE ABOVE THE DGZ AND LEAD TO MORE COLUMN/PLATE SNOW TYPE...AT LEAST FOR WEDNESDAY NIGHT AND THURSDAY. THIS WILL LEAD TO LOWER SNOW RATIOS THAN WHAT HAVE BEEN SEEN OVER THE LAST DAY AND GENERALLY IN THE 15-20 TO 1 RANGE. THE PERSISTENT NATURE OF THE SNOW DURING THIS PERIOD WILL LIKELY PRODUCE DECENT LAKE EFFECT SNOW ACCUMULATIONS IN THE FAVORED LOCATIONS AND WILL CONTINUE TO MENTION PERIODS OF MODERATE SNOW IN THE HWO. SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS PERIOD OF LES...WILL MAKE THE JUMP UP TO DEFINITE POPS IN THE WNW TO NW FAVORED AREAS. TIMING OF SHORTWAVES AND ASSOCIATED POCKETS OF DEEPER MOISTURE ARE DIFFICULT TO LOCATE/TIME IN NORTHWEST FLOW...BUT THEY COULD LEAD TO PERIODS OF HEAVY SNOW. THIS WOULD ESPECIALLY BE TRUE ON THURSDAY AFTERNOON/NIGHT WHEN TEMPS WARM SLIGHTLY TO RAISE THE DGZ FROM THE SURFACE. 00Z GFS/ECMWF HAVE GOOD CONSISTENCY WITH SHORTWAVE AND CLIPPER SYSTEM AFFECTING THE AREA ON FRIDAY. CONFIDENCE IN TIMING/LOCATION STILL IS LOW...BUT THE LATEST TRENDS SUGGEST A BETTER H850 WAA FOCUS ACROSS THE CWA FOR FRIDAY. THIS WOULD LEAD TO BETTER SNOWFALL CHANCES /1-2IN OF ACCUM OVER MUCH OF THE CWA/ THAN THE LOW END CHANCES THAT ARE CURRENTLY IN PLACE. IF MODELS CONTINUE TO SHOW THIS IDEA...WILL NEED TO BUMP UP POPS. NORTHWEST FLOW ALOFT WILL CONTINUE INTO THE WEEKEND AS A UPPER RIDGE BUILDS OVER THE PACIFIC NORTHWEST. BUT MODELS ARE REALLY STARTING TO DIFFER IN THE UPPER LOW SPINNING EAST OF HUDSON BAY AND WHAT HAPPENS TO IT THROUGH THE WEEKEND. NO MATTER THE SOLUTION...IT APPEARS THE AREA WILL STILL BE UNDER THE INFLUENCE OF THE UPPER TROUGH BUT THERE APPEARS TO BE STRONGER SHORTWAVES DISRUPTING THE TROUGH SOME. THESE DISRUPTIONS PRODUCES MORE UNCERTAINTY IN THE LOW TRACK FORECAST...WHICH MAKES THE LOW LEVEL WIND FIELDS HIGHLY VARIABLE FOR PINNING DOWN LAKE EFFECT AREAS IN ADDITION TO SYNOPTIC SNOW. WILL FOLLOW A GENERAL MODEL CONSENSUS...WHICH WILL CONTINUE TO FOCUS THE HIGHEST CHANCE POPS NEAR LAKE SUPERIOR. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 638 AM EST MON JAN 14 2013 CMX...EXPECT PREDOMINANT IFR CONDITIONS THRU TODAY WITH PERSISTENT/ UPSLOPE WNW FLOW AND SUFFICIENT INSTABILITY FOR LES. THE BEST CHC FOR LIFR WX WL BE 15Z-21Z TODAY...WHEN AXIS OF ENHANCED LOW LEVEL CONVERGENCE ASSOCIATED WITH SLOWLY BACKING LARGER SCALE FLOW WL SHIFT OVHD. HOWEVER...CONFIDENCE IN THE TIMING AND STRENGTH OF THE BAND IS MARGINAL. AS THE FLOW BACKS MORE TO THE WSW...THE HEAVIER SHSN SHOULD SHIFT TO THE N OF THE SITE AND ALLOW A RETURN OF PREDOMINANT MVFR CONDITIONS AND LIGHTER -SHSN. IWD/SAW...ALTHOUGH SOME MVFR CONDITIONS MIGHT IMPACT THESE SITES EARLY IN THE PERIOD...A SLOWLY BACKING LLVL FLOW TOWARD THE WSW WL ADVECT DRIER AIR OVHD AND ALLOW FOR MAINLY VFR WX. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 535 AM EST MON JAN 14 2013 NORTHWEST WINDS WILL GRADUALLY BACK TODAY AND TONIGHT...WITH MOST LOCATIONS SEEING WINDS IN THE 15-25KT RANGE. AS A COLD FRONT APPROACHES THE AREA ON TUESDAY AND TUESDAY EVENING...SOUTHWEST WINDS WILL INCREASE TO GALES OF 35-45KTS FOR TUESDAY NIGHT. THEN AS THE FRONT MOVES THROUGH ON WEDNESDAY MORNING...THE WINDS ARE EXPECTED TO VEER TO THE NORTHWEST AND STILL PRODUCE GALES TO 40KTS. THE TIMING OF THE GALE WATCH LOOKS TO BE IN GOOD SHAPE AND WILL KEEP IT IN PLACE. NORTHWEST FLOW WILL REMAIN WEDNESDAY NIGHT INTO THURSDAY NIGHT...WITH WINDS GENERALLY IN THE 15-30KT RANGE WITH A FEW GUSTS TO 35KTS ON THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ002. LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ006-007. LAKE SUPERIOR... GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR LSZ265>267. GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...JLB MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
536 AM EST MON JAN 14 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 535 AM EST MON JAN 14 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH EXTENDING FROM HUDSON BAY THROUGH THE NRN PLAINS INTO THE SW CONUS. THE SHORTWAVE TROUGH THAT BROUGHT -SN/FLURRIES TO UPPER MI AND HELPED ENHANCED THE LES INTO THE WEST HAD LIFTED OFF TO THE NORTHEAST TOWARD QUEBEC. IN ITS WAKE...SHRTWV RIDGING WITH QVECTOR DIV AND SUBSIDENCE HAS HELPED LIMIT LES INTENSITY OVERNIGHT. UPSTREAM...ONLY A WEAK SHRTWV WAS NOTED OVER NEBRASKA. AT THE SFC...A RIDGE EXTENDED FROM SASK THROUGH THE NRN PLAINS INTO THE MID MS VALLEY RESULTING IN W TO WNW FLOW THROUGH THE NRN GREAT LAKES. THE LINGERING LAKE INDUCED TROUGH HAS KEPT THE FOCUS OF LES OVER THE KEWEENAW AND FOR LOCATIONS EAST OF P53. INSTABILITY FOR LES WILL REMAIN FAVORABLE WITH 850 MB TEMPS NEAR -19C PRODUCING LAKE INDUCED CAPES IN THE 400-500 J/KG RANGE. THE DGZ WILL ALSO REMAIN IN THE CONVECTIVE LAYER...LEADING TO HIGH SNOW/WATER RATIOS IN THE 25/1 TO 30/1 RANGE. UPSTREAM LOW LEVEL MOISTURE OVER NRN MN WILL HELP MAINTAIN LES ACROSS WRN LAKE SUPERIOR. MODELS WERE CONSISTENT IN SUGGESTING THAT LOW LEVEL WINDS WILL SLOWLY BACK. AS A RESULT...THE LES INTO THE ERN CWA COULD PRODUCE AN ADDITIONAL 1 TO 3 INCHES BEFORE THE BANDS GRADUALLY SHIFT TOWARD THE SHORELINE AND MOVE OUT OF THE AREA THIS AFTERNOON. OVER THE WEST... THE HIGHER RES MODELS SUGGEST THAT THE STRONGEST LES BAND(S) MAINLY NEAR THE SHORELINE OF ONTONAGON COUNTY TOWARD TWIN LAKES THIS MORNING WOULD GRADUALLY SHIFT THROUGH NRN HOUGHTON COUNTY TODAY AND EVENTUALLY TO CMX-P59 TONIGHT. THERE IS LOWER CONFIDENCE WITH THE SNOWFALL RATES AND AMOUNT OF TIME IT WILL LINGER OVER ANY GIVEN AREA. THE POTENTIAL REMAINS FOR LOCAL AMOUNTS IN THE 4 TO 8 INCH RANGE BOTH TODAY AND TONIGHT AS IT LIFTS THROUGH THESE AREAS. SO...THE LES WARNING WILL CONTINUE AT LEAST UNTIL 12Z/TUE. OVER THE REST OF THE CWA...EXPECT MAINLY JUST A FEW FLURRIES OVER THE NORTH OUTSIDE OF THE MAIN LES AREA. EVEN WITH MORE SUNSHINE TODAY OVER THE SOUTH...TEMPERATURES WILL REMAIN AT OR BELOW NORMAL FROM 12 TO 17 WEST AND IN THE LOWER 20S EAST. THERE MAY ALSO BE ENOUGH CLEARING TONIGHT INLAND WITH LIGHT WSW WINDS AS THE RIDGE BUILDS TOWARD THE REGION TO ALLOW TEMPS TO DIP TO AROUND ZERO. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 535 AM EST MON JAN 14 2013 TUESDAY LOOKS TO BE ONE OF THE FEW BREAKS FROM SNOW FOR MUCH OF THE LAND CWA...AS WINDS BACK TO THE WEST-SOUTHWEST AHEAD OF AN APPROACHING SHORTWAVE AND ASSOCIATED COLD FRONT. THIS WILL PUSH WHAT IS LEFT OF THE BANDS CURRENTLY OVER NORTHERN HOUGHTON AND KEWEENAW COUNTIES ALONG THE WESTERN SHORELINE DURING THE MORNING AND THEN OFFSHORE DURING THE AFTERNOON. THE BANDS WILL ALSO BE DIMINISHING IN INTENSITY DUE TO INCREASING H850 TEMPS. ELSEWHERE...LOOKS TO BE A FAIRLY NICE DAY WITH ONLY A FEW MID LEVEL CLOUDS MOVING THROUGH. HEADING INTO TUESDAY NIGHT...LOOKS LIKE IT COULD BE GUSTY ACROSS MUCH OF UPPER MICHIGAN AHEAD OF THE COLD FRONT. GALES OVER LAKE SUPERIOR STILL LOOK LIKELY...SO WILL CONTINUE GALE WATCH. OVER LAND...INVERSION WILL KEEP MUCH OF THE STRONG 50-60KT LOW LEVEL JET ALOFT. BUT LATE IN THE NIGHT...THINK IT WILL GET A LITTLE GUSTY AS THE 10-14MB 6HR PRESSURE FALLS MOVE ACROSS THE CWA. STRONGEST WINDS WILL LIKELY END UP IN THE SOUTHWEST WIND DOWNSLOPE AREAS NEAR LAKE SUPERIOR...MAYBE APPROACHING 35-45MPH...WHILE THE REST OF THE AREA WILL SEE A FEW HOUR PERIOD OF 25-35MPH GUSTS. THERE IS MUCH BETTER AGREEMENT WITH THE SHORTWAVE AND ASSOCIATED COLD FRONT THAT MOVES THROUGH LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DUE TO THIS...HAVE DELAYED THE START OF THE SNOW INTO THE OVERNIGHT HOURS. BEST H500 HEIGHT FALLS STAY OVER NORTHERN LAKE SUPERIOR AND SOUTHERN ONTARIO...BUT DECENT H850-500 Q-VECTOR CONVERGENCE MOVES OVER THE NORTHERN HALF OF THE CWA. WILL CONTINUE TO HIGHLIGHT THE HIGHEST POPS OVER THE NORTH HALF OF THE CWA...WITH CHANCES ELSEWHERE. WITH IT MOVING THROUGH FAIRLY QUICKLY...DON/T THINK THERE WILL BE TOO MUCH SNOW ACCUMULATION...WITH THE HIGHEST AMOUNTS OVER THE KEWEENAW AND LUCE COUNTY WHERE THERE COULD BE SOME ENHANCEMENT OFF LAKE MICHIGAN. THE LEAST AMOUNTS WILL LIKELY BE OVER THE CENTRAL CWA...WHERE DRY LOW LEVEL AIR WILL LEAD TO SOME INITIAL EVAPORATION OF THE SNOW. THERE IS A SLIGHT DELAY IN THE COLD AIR SURGING IN BEHIND THE FRONT...SO AFTER SNOW DIMINISHES ON WEDNESDAY MORNING AND EARLY AFTERNOON...PROBABLY WONT BE MUCH GOING ON LAKE EFFECT WISE UNTIL THE COLDER ARRIVES LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. BEHIND THE FRONT...PERSISTENT LAKE EFFECT SNOW IS EXPECTED WEDNESDAY NIGHT THROUGH THURSDAY NIGHT FOR WEST TO NORTHWEST FLOW FAVORED LOCATIONS. THE AREA WILL BE BETWEEN THE SURFACE LOW ROTATING OVER HUDSON BAY AND A HIGH PRESSURE IN THE PLAINS STATES. H850 TEMPS FALLING TO AROUND -24C BEHIND THE FRONT SHOULD PRODUCE SIGNIFICANT LAKE INSTABILITY DUE TO LAKE SUPERIOR WATER TEMPS AROUND 3C. SINCE MODELS ARE SHOWING THE INVERSION AROUND 5KFT TO BE FAIRLY WEAK...LAKE INDUCED EQL LEVELS RISE TO 9-10KFT AND CAPE VALUES APPROACH 900 J/KG. THESE ARE FAIRLY IMPRESSIVE VALUES...BUT THE CONCERN WITH SIGNIFICANT SNOWFALL COMES WITH THE BEST MOISTURE FOCUSED IN THE 2-5KFT RANGE. WITH THE COLD AIR...THE CONVECTIVE PORTION OF THE LAKE EFFECT SHOULD BE ABOVE THE DGZ AND LEAD TO MORE COLUMN/PLATE SNOW TYPE...AT LEAST FOR WEDNESDAY NIGHT AND THURSDAY. THIS WILL LEAD TO LOWER SNOW RATIOS THAN WHAT HAVE BEEN SEEN OVER THE LAST DAY AND GENERALLY IN THE 15-20 TO 1 RANGE. THE PERSISTENT NATURE OF THE SNOW DURING THIS PERIOD WILL LIKELY PRODUCE DECENT LAKE EFFECT SNOW ACCUMULATIONS IN THE FAVORED LOCATIONS AND WILL CONTINUE TO MENTION PERIODS OF MODERATE SNOW IN THE HWO. SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS PERIOD OF LES...WILL MAKE THE JUMP UP TO DEFINITE POPS IN THE WNW TO NW FAVORED AREAS. TIMING OF SHORTWAVES AND ASSOCIATED POCKETS OF DEEPER MOISTURE ARE DIFFICULT TO LOCATE/TIME IN NORTHWEST FLOW...BUT THEY COULD LEAD TO PERIODS OF HEAVY SNOW. THIS WOULD ESPECIALLY BE TRUE ON THURSDAY AFTERNOON/NIGHT WHEN TEMPS WARM SLIGHTLY TO RAISE THE DGZ FROM THE SURFACE. 00Z GFS/ECMWF HAVE GOOD CONSISTENCY WITH SHORTWAVE AND CLIPPER SYSTEM AFFECTING THE AREA ON FRIDAY. CONFIDENCE IN TIMING/LOCATION STILL IS LOW...BUT THE LATEST TRENDS SUGGEST A BETTER H850 WAA FOCUS ACROSS THE CWA FOR FRIDAY. THIS WOULD LEAD TO BETTER SNOWFALL CHANCES /1-2IN OF ACCUM OVER MUCH OF THE CWA/ THAN THE LOW END CHANCES THAT ARE CURRENTLY IN PLACE. IF MODELS CONTINUE TO SHOW THIS IDEA...WILL NEED TO BUMP UP POPS. NORTHWEST FLOW ALOFT WILL CONTINUE INTO THE WEEKEND AS A UPPER RIDGE BUILDS OVER THE PACIFIC NORTHWEST. BUT MODELS ARE REALLY STARTING TO DIFFER IN THE UPPER LOW SPINNING EAST OF HUDSON BAY AND WHAT HAPPENS TO IT THROUGH THE WEEKEND. NO MATTER THE SOLUTION...IT APPEARS THE AREA WILL STILL BE UNDER THE INFLUENCE OF THE UPPER TROUGH BUT THERE APPEARS TO BE STRONGER SHORTWAVES DISRUPTING THE TROUGH SOME. THESE DISRUPTIONS PRODUCES MORE UNCERTAINTY IN THE LOW TRACK FORECAST...WHICH MAKES THE LOW LEVEL WIND FIELDS HIGHLY VARIABLE FOR PINNING DOWN LAKE EFFECT AREAS IN ADDITION TO SYNOPTIC SNOW. WILL FOLLOW A GENERAL MODEL CONSENSUS...WHICH WILL CONTINUE TO FOCUS THE HIGHEST CHANCE POPS NEAR LAKE SUPERIOR. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1209 AM EST MON JAN 14 2013 CMX...EXPECT PREDOMINANT IFR CONDITIONS THRU TODAY WITH PERSISTENT/ UPSLOPE WNW FLOW AND SUFFICIENT INSTABILITY FOR LES. THE BEST CHC FOR LIFR WX WL BE 12Z-18Z TODAY...WHEN AXIS OF ENHANCED LLVL CNVGC ASSOCIATED WITH SLOWLY BACKING LARGER SCALE FLOW WL SHIFT OVHD. AS THE FLOW BACKS MORE TO THE WSW...THE HEAVIER SHSN SHOULD SHIFT TO THE N OF THE SITE AND ALLOW A RETURN OF PREDOMINANT MVFR CONDITIONS/ LIGHTER -SHSN. IWD/SAW...ALTHOUGH SOME MVFR CONDITIONS MIGHT IMPACT THESE SITES EARLY IN THE PERIOD...A SLOWLY BACKING LLVL FLOW TOWARD THE WSW WL ADVECT DRIER AIR OVHD AND ALLOW A RETURN OF PREDOMINANT VFR WX. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 535 AM EST MON JAN 14 2013 NORTHWEST WINDS WILL GRADUALLY BACK TODAY AND TONIGHT...WITH MOST LOCATIONS SEEING WINDS IN THE 15-25KT RANGE. AS A COLD FRONT APPROACHES THE AREA ON TUESDAY AND TUESDAY EVENING...SOUTHWEST WINDS WILL INCREASE TO GALES OF 35-45KTS FOR TUESDAY NIGHT. THEN AS THE FRONT MOVES THROUGH ON WEDNESDAY MORNING...THE WINDS ARE EXPECTED TO VEER TO THE NORTHWEST AND STILL PRODUCE GALES TO 40KTS. THE TIMING OF THE GALE WATCH LOOKS TO BE IN GOOD SHAPE AND WILL KEEP IT IN PLACE. NORTHWEST FLOW WILL REMAIN WEDNESDAY NIGHT INTO THURSDAY NIGHT...WITH WINDS GENERALLY IN THE 15-30KT RANGE WITH A FEW GUSTS TO 35KTS ON THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ002. LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ006-007. LAKE SUPERIOR... GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR LSZ265>267. GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...KC MARINE...SRF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1036 AM EST MON JAN 14 2013 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL PRODUCE UNSEASONABLY WARM CONDITIONS INTO MID-WEEK. A COLD FRONT WILL MOVE SLOWLY THROUGH THE AREA LATE WEDNESDAY. WEAK GULF COAST LOW PRESSURE MAY BRING A CHANCE OF LIGHT RAIN TO THE REGION THURSDAY NIGHT OR FRIDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM MONDAY...HAVE ADJUSTED TEMPS UP A COUPLE OF DEGREES FOR TODAY KEEPING MAX TEMPS IN THE MID TO UPPER 70S. THE SOUTHWESTERLY WINDS WILL BACK A BIT PRODUCING MORE OF AN ON SHORE FLOW THROUGH THE AFTERNOON. THIS WILL KEEP TEMPS COOLER ALONG THE SHORE...MOVING INLAND AS WINDS PICK UP THROUGH THE AFTERNOON. SEA FOG WILL ALSO HELP TO KEEP TEMPS COOLER ALONG THE COAST. PREVIOUS DISCUSSION...MODELS INDICATE THE MID TO UPPER LEVEL RIDGE TO REMAIN ANCHORED JUST OFF THE SE U.S. COAST DURING THIS NEAR TERM PERIOD. THIS WILL SLOW DOWN THE PROGRESSION OF THE BAROCLINIC ZONE IE. THE SFC COLD FRONT...TOWARD THE SOUTHEAST. IN FACT... MODELS ACTUALLY STALL THE COLD FRONT JUST NORTH AND WEST OF THE FA AS IT BECOMES ORIENTED PARALLEL WITH THE FLOW ALOFT. THE DEEPEST MOISTURE WILL REMAIN JUST OUTSIDE OF THE ILM CWA DURING THIS NEAR TERM PERIOD...REMAINING WEST THROUGH NORTH OF THE FA. AMAZINGLY... GFS/NAM/EUROPEAN/ETC. AGREE THAT THIS SCENARIO WILL PLAY OUT. NOW WHAT THEY DO NOT AGREE IS THE THREAT OR PROBABILITY FOR PCPN. WITH THE BEST LIFT REMAINING OUTSIDE OF THE ILM CWA DOMAIN...HAVE INDICATED A LOW CHANCE OF POPS FOR THE NW PORTIONS OF THE FA FROM THIS AFTERNOON THROUGH TONIGHT...ROUGHLY ALONG AND WEST OF THE I-95 CORRIDOR. THE LATEST RUN OF THE HRRR MODEL ALSO INDICATES THIS PCPN POSSIBILITY. HAVE STAYED AWAY FROM MENTIONING THUNDER DUE TO THE LACK OF INSTABILITY ILLUSTRATED BY LATEST NAMBUFR SOUNDINGS...IE. NO CAPE...LI`S STAY MAINLY POSITIVE. WILL LIKELY HAVE A SOMEWHAT OF A SHARP CLOUD GRADIENT ACROSS THE FA WITH THE IMMEDIATE COAST HAVING THE BEST POTENTIAL TO OBSERVE THE DAYS INSOLATION. THEREFORE...HAVE RELIED ON THE WARMER MODEL MOS GUIDANCE FOR BOTH TODAYS MAX AND TONIGHTS MIN TEMPS. THIS WILL RESULT IN ADDITIONAL MAX TEMP RECORDS LIKELY BEING SET FOR 1 MORE DAY. AND FINALLY...THE MID TO UPPER LEVEL CLOUD DECK ACROSS THE FA HAS BEEN OPAQUE ENOUGH TO PREVENT WIDESPREAD RADIATIONAL TYPE DENSE FOG. HOWEVER...SEA FOG IE. ADVECTION TYPE FOG...WILL SPORADICALLY AFFECT THE IMMEDIATE COAST AS SFC WINDS SLIGHTLY BACK TO THE SSW AND PUSH 60+ DEWPOINTS ACROSS SSTS IN THE 50S RESULTING WITH SEA FOG BRIEFLY PUSHING ONSHORE AT TIMES. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 245 AM MONDAY...WEAK FRONT WILL BE STALLED IN OR JUST WEST OF THE REGION FOR A MAJORITY OF THE PERIOD. PROXIMITY TO FRONT WILL CREATE SIGNIFICANT TEMP GRADIENT ACROSS THE REGION...PROVIDING PLENTY OF POTENTIAL FOR THE FORECAST TO GO WRONG. SOME WEAK ISENTROPIC LIFT AND LOW LEVEL MOISTURE MAY PRODUCE SOME PATCHY LIGHT RAIN AT TIMES. ALTHOUGH DRY MID AND UPPER LEVELS WILL LIKELY KEEP MUCH OF THE AREA DRY FOR A MAJORITY OF THE PERIOD. COMBINATION OF FRONT IN THE REGION AND LOW LEVEL CLOUD COVER WILL TEMPER HIGHS ACROSS PORTIONS OF THE FORECAST AREA BOTH DAYS. COASTAL SC ENDS UP WARMEST WITH A LITTLE LESS CLOUD COVER AND SOUTHERLY FLOW INTO WED NIGHT. HIGHS WILL BE IN THE LOW 70S WITH LOWS IN THE UPPER 50S TO AROUND 60. INLAND SC AND NC WILL HAVE BEST PRECIP CHANCES...THOUGH AT THIS POINT LITTLE MORE THAN LOW CHANCE OR SLIGHT CHANCE APPEARS WARRANTED. HIGH TEMP FORECAST WILL BE TRICKY IN THESE AREAS WITH LOCATION OF FRONT...AND THE NORTHERLY FLOW BEHIND IT...LEADING TO A SHARP GRADIENT SOMEWHERE IN THE FORECAST AREA. FOR NOW WILL GO WITH HIGHS NEAR TO ABOVE CLIMO TUE AND ABOVE TO WELL ABOVE CLIMO WED. HOWEVER A MORE EASTERLY POSITION OF THE FRONT WED...SOMETHING GUIDANCE IS TRENDING AWAY FROM...WOULD RESULT IN COOLER TEMPS. LOWS WILL CONTINUE TO RUN ABOVE CLIMO REGARDLESS OF FRONTAL POSITION GIVEN PLENTY OF CLOUD COVER AND LIMITED COLD ADVECTION ON BACKSIDE OF THE BOUNDARY. FRONT IS PULLED OFF THE COAST WED NIGHT BY WEAK SURFACE LOW MOVING INTO THE CANADIAN MARITIMES. LACK OF ANY MID LEVEL PUSH TRANSLATES TO MINIMAL TEMP REDUCTION AS THE PERIOD ENDS. NORTH TO NORTHEAST FLOW ACROSS THE AREA BY END OF PERIOD ONLY DROPS WED NIGHT LOWS A FEW DEGREES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 245 AM MONDAY...SOUTHERN STREAM SYSTEM EMERGING FROM THE SOUTHWEST MID WEEK WILL BRING THE PERIODS BEST AND ONLY PRECIP CHANCE THU NIGHT INTO FRI. DEEP SOUTHWEST FLOW AHEAD OF THE WAVE AS IT CROSSES THE GULF COAST INCREASES MOISTURE OVER THE SOUTHEAST THU. DIVERGENT PATTERN ALOFT THU NIGHT INTO FRI IS ENHANCED BY 200MB JET STREAK APPROACHING 120 KT. RIGHT NOW THE BIGGEST NEGATIVE FACTOR APPEARS TO BE THE TRACK OF THE MID LEVEL FEATURE AND THE ASSOCIATED SURFACE WAVE. WEAK SURFACE LOW DEVELOPS ALONG FRONT STALLED ACROSS NORTHERN GOMEX EARLY THU. THIS LOW TRACKS NORTHEAST ALONG THE FRONT...PASSING OFF THE SOUTHEAST COAST. THIS KEEPS NORTHEAST LOW LEVEL FLOW IN PLACE FOR THE DURATION OF THE EVENT. BELOW 700MB OR SO FORECAST SOUNDINGS DEPICT A SATURATED BUT VERY STABLE AIR MASS. SO WHILE MID AND UPPER LEVEL FORCING WILL BE PRESENT IT APPEARS THE LOW LEVEL STABILITY WILL ULTIMATELY WIN OUT. THUS HAVE GONE FOR LOWER POP AND MINIMAL QPF EARLY IN THE PERIOD. AS SURFACE AND MID LEVEL FEATURES MOVE OFF TO THE NORTHEAST HIGH PRESSURE BUILDS IN UNDER DEVELOPING PROGRESSIVE MID LEVEL PATTERN. THIS ALLOWS MUCH DRIER AND COOLER AIR TO SPREAD IN FROM THE WEST. PINCHED GRADIENT ALONG THE COAST WILL KEEP NORTHEAST FLOW BRISK INTO SAT MORNING...ESPECIALLY ALONG THE COAST. LATE IN THE PERIOD MEDIUM RANGE GUIDANCE IS TRYING TO SHOW A WEAK COASTAL LOW DEVELOPING ON REMAINS OF STALLED SURFACE BOUNDARY. GIVEN THE TIME RANGE AND POTENTIAL FOR SIGNIFICANT CHANGES REGARDING THIS FEATURE WILL NOT INTRODUCE A POP LATE IN THE PERIOD. TEMPS NEAR CLIMO THROUGH THE PERIOD. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 12Z...LBT IS LIFR AND WILL LIKELY NOT REACH VFR UNTIL 14Z...PERHAPS EVEN AN HOUR LATER. THE OTHER TERMINALS APPEAR TO HAVE ENOUGH SOUTHWEST FLOW TO MIX OUT A BIT EARLIER. STAGNANT SYNOPTIC PATTERN WILL KEEP THE FRONT WEST OF THE REGION...WITH MAINLY THICK HIGH CLOUDS IN AND OUT OF OUR WESTERN TERMINALS. ALONG THE COAST...GOOD LOW LEVEL MOISTURE WILL GIVE US A CHANCE OF AN MVFR CEILING IN AND OUT THROUGH EARLY AFTERNOON. SOUTHWEST FLOW WILL CONTINUE THROUGH THE OVERNIGHT HOURS. IT APPEARS THE WINDS WILL BE TOO STRONG TO SUPPORT FOG...BUT WILL REEVALUATE ON THE NEXT SET OF TAFS. EXTENDED OUTLOOK...POSSIBLE RESTRICTIONS IN ASSOCIATION WITH COLD FRONT TUESDAY AND WEDNESDAY...MAINLY AT THE INLAND TERMINALS. CHANCE FOR SHOWERS THURSDAY. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM MONDAY...SFC PRESSURE PATTERN INDICATES THE WESTERN ATLANTIC HIGH...CENTERED OFFSHORE FROM THE SE U.S. COAST...WILL PRODUCE SSW THROUGH WSW WIND DIRECTIONS. THE SFC PG WILL SLIGHTLY TIGHTEN AS THE SFC COLD FRONT APPROACHES FROM THE NW TODAY... BEFORE STALLING BETWEEN DUCK NC SOUTHWEST TO PENSACOLA BEACH FLORIDA TONIGHT. LOOK FOR WIND SPEEDS AT 5 TO 10 KT THIS MORNING...INCREASING TO 10 TO POSSIBLY 15 KT THIS AFTERNOON AND TONIGHT. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT...EXCEPT UP TO 4 FT ACROSS THE OUTER WATERS OFF CAPE FEAR THIS AFTERNOON AND/OR TONIGHT. GENERALLY...A 1 1/2 TO 2 1/2 FOOT ESE GROUND SWELL EXHIBITING 9 TO 12 SECOND PERIODS WILL DOMINATE SIG. SEAS. THE ADDITION OF 3 TO 5 SECOND PERIOD WIND DRIVEN WAVES WILL PUSH SIG. SEAS TO THE 4 FOOT LEVEL OFF CAPE FEAR LATER TODAY AND TONIGHT. SEA FOG WILL ALSO REMAIN A THREAT TO MARINERS THIS FORECAST PERIOD...OCCASIONALLY AND BRIEFLY MOVING ONSHORE. VSBY ROUGHLY 1 NM OR LESS WITHIN THE SEA FOG. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 245 AM MONDAY...SOUTHWEST FLOW REMAINS IN PLACE FOR A MAJORITY OF THE PERIOD WITH SPEEDS GENERALLY 10 TO 15 KT. WEAK SLOW MOVING FRONT DROPPING IN FROM THE NORTH-NORTHWEST LATE IN THE PERIOD WILL BRING ABOUT A WIND SHIFT TO NORTHERLY BY THE END OF THE PERIOD BUT LACK OF COLD ADVECTION OR SIGNIFICANT GRADIENT WILL KEEP SPEEDS LIGHT...10 KT OR LESS. SEAS WILL RUN 2 TO 4 FT THROUGH THE PERIOD...MAINLY AS SOUTHERLY WIND WAVE. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 245 AM MONDAY...NORTH TO NORTHEAST FLOW THU STARTS TO INCREASE THU NIGHT...BUT QUESTION REMAINS BY HOW MUCH. WEAK LOW PRESSURE EMERGING FROM NORTHEAST GOMEX WILL PINCH GRADIENT...BUT HOW TIGHT GRADIENT BETWEEN THIS LOW AND THE HIGH BUILDING IN FROM THE NORTHWEST BECOMES IS UNCERTAIN. ALL OF THE MEDIUM RANGE GUIDANCE DEPICTS THIS SURFACE WAVE PASSING EAST OF THE WATERS LATE THU NIGHT OR EARLY FRI...SO FEEL THAT AN INCREASE IN NORTHEAST FLOW IS LIKELY FOR SECOND HALF OF THE PERIOD. AT THIS POINT CANNOT SAY IF HEADLINES WILL BE NEEDED BUT IT CERTAINLY APPEARS TO BE A POSSIBILITY. CURRENT SEAS FORECAST IS 2 TO 4 FT THU BUILDING TO 3 TO 5 ON FRI. HOWEVER IT IS WORTH NOTING THAT WW3 GUIDANCE IS COMING IN CLOSE TO 10 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...RGZ SHORT TERM...III LONG TERM...III AVIATION...DL MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
641 AM EST MON JAN 14 2013 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL PRODUCE UNSEASONABLY WARM CONDITIONS INTO MID-WEEK. A COLD FRONT WILL MOVE SLOWLY THROUGH THE AREA LATE WEDNESDAY. WEAK GULF COAST LOW PRESSURE MAY BRING A CHANCE OF LIGHT RAIN TO THE REGION THURSDAY NIGHT OR FRIDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM MONDAY...MODELS INDICATE THE MID TO UPPER LEVEL RIDGE TO REMAIN ANCHORED JUST OFF THE SE U.S. COAST DURING THIS NEAR TERM PERIOD. THIS WILL SLOW DOWN THE PROGRESSION OF THE BAROCLINIC ZONE IE. THE SFC COLD FRONT...TOWARD THE SOUTHEAST. IN FACT... MODELS ACTUALLY STALL THE COLD FRONT JUST NORTH AND WEST OF THE FA AS IT BECOMES ORIENTED PARALLEL WITH THE FLOW ALOFT. THE DEEPEST MOISTURE WILL REMAIN JUST OUTSIDE OF THE ILM CWA DURING THIS NEAR TERM PERIOD...REMAINING WEST THROUGH NORTH OF THE FA. AMAZINGLY... GFS/NAM/EUROPEAN/ETC. AGREE THAT THIS SCENARIO WILL PLAY OUT. NOW WHAT THEY DO NOT AGREE IS THE THREAT OR PROBABILITY FOR PCPN. WITH THE BEST LIFT REMAINING OUTSIDE OF THE ILM CWA DOMAIN...HAVE INDICATED A LOW CHANCE OF POPS FOR THE NW PORTIONS OF THE FA FROM THIS AFTERNOON THROUGH TONIGHT...ROUGHLY ALONG AND WEST OF THE I-95 CORRIDOR. THE LATEST RUN OF THE HRRR MODEL ALSO INDICATES THIS PCPN POSSIBILITY. HAVE STAYED AWAY FROM MENTIONING THUNDER DUE TO THE LACK OF INSTABILITY ILLUSTRATED BY LATEST NAMBUFR SOUNDINGS...IE. NO CAPE...LI`S STAY MAINLY POSITIVE. WILL LIKELY HAVE A SOMEWHAT OF A SHARP CLOUD GRADIENT ACROSS THE FA WITH THE IMMEDIATE COAST HAVING THE BEST POTENTIAL TO OBSERVE THE DAYS INSOLATION. THEREFORE...HAVE RELIED ON THE WARMER MODEL MOS GUIDANCE FOR BOTH TODAYS MAX AND TONIGHTS MIN TEMPS. THIS WILL RESULT IN ADDITIONAL MAX TEMP RECORDS LIKELY BEING SET FOR 1 MORE DAY. AND FINALLY...THE MID TO UPPER LEVEL CLOUD DECK ACROSS THE FA HAS BEEN OPAQUE ENOUGH TO PREVENT WIDESPREAD RADIATIONAL TYPE DENSE FOG. HOWEVER...SEA FOG IE. ADVECTION TYPE FOG...WILL SPORADICALLY AFFECT THE IMMEDIATE COAST AS SFC WINDS SLIGHTLY BACK TO THE SSW AND PUSH 60+ DEWPOINTS ACROSS SSTS IN THE 50S RESULTING WITH SEA FOG BRIEFLY PUSHING ONSHORE AT TIMES. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 245 AM MONDAY...WEAK FRONT WILL BE STALLED IN OR JUST WEST OF THE REGION FOR A MAJORITY OF THE PERIOD. PROXIMITY TO FRONT WILL CREATE SIGNIFICANT TEMP GRADIENT ACROSS THE REGION...PROVIDING PLENTY OF POTENTIAL FOR THE FORECAST TO GO WRONG. SOME WEAK ISENTROPIC LIFT AND LOW LEVEL MOISTURE MAY PRODUCE SOME PATCHY LIGHT RAIN AT TIMES. ALTHOUGH DRY MID AND UPPER LEVELS WILL LIKELY KEEP MUCH OF THE AREA DRY FOR A MAJORITY OF THE PERIOD. COMBINATION OF FRONT IN THE REGION AND LOW LEVEL CLOUD COVER WILL TEMPER HIGHS ACROSS PORTIONS OF THE FORECAST AREA BOTH DAYS. COASTAL SC ENDS UP WARMEST WITH A LITTLE LESS CLOUD COVER AND SOUTHERLY FLOW INTO WED NIGHT. HIGHS WILL BE IN THE LOW 70S WITH LOWS IN THE UPPER 50S TO AROUND 60. INLAND SC AND NC WILL HAVE BEST PRECIP CHANCES...THOUGH AT THIS POINT LITTLE MORE THAN LOW CHANCE OR SLIGHT CHANCE APPEARS WARRANTED. HIGH TEMP FORECAST WILL BE TRICKY IN THESE AREAS WITH LOCATION OF FRONT...AND THE NORTHERLY FLOW BEHIND IT...LEADING TO A SHARP GRADIENT SOMEWHERE IN THE FORECAST AREA. FOR NOW WILL GO WITH HIGHS NEAR TO ABOVE CLIMO TUE AND ABOVE TO WELL ABOVE CLIMO WED. HOWEVER A MORE EASTERLY POSITION OF THE FRONT WED...SOMETHING GUIDANCE IS TRENDING AWAY FROM...WOULD RESULT IN COOLER TEMPS. LOWS WILL CONTINUE TO RUN ABOVE CLIMO REGARDLESS OF FRONTAL POSITION GIVEN PLENTY OF CLOUD COVER AND LIMITED COLD ADVECTION ON BACKSIDE OF THE BOUNDARY. FRONT IS PULLED OFF THE COAST WED NIGHT BY WEAK SURFACE LOW MOVING INTO THE CANADIAN MARITIMES. LACK OF ANY MID LEVEL PUSH TRANSLATES TO MINIMAL TEMP REDUCTION AS THE PERIOD ENDS. NORTH TO NORTHEAST FLOW ACROSS THE AREA BY END OF PERIOD ONLY DROPS WED NIGHT LOWS A FEW DEGREES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 245 AM MONDAY...SOUTHERN STREAM SYSTEM EMERGING FROM THE SOUTHWEST MID WEEK WILL BRING THE PERIODS BEST AND ONLY PRECIP CHANCE THU NIGHT INTO FRI. DEEP SOUTHWEST FLOW AHEAD OF THE WAVE AS IT CROSSES THE GULF COAST INCREASES MOISTURE OVER THE SOUTHEAST THU. DIVERGENT PATTERN ALOFT THU NIGHT INTO FRI IS ENHANCED BY 200MB JET STREAK APPROACHING 120 KT. RIGHT NOW THE BIGGEST NEGATIVE FACTOR APPEARS TO BE THE TRACK OF THE MID LEVEL FEATURE AND THE ASSOCIATED SURFACE WAVE. WEAK SURFACE LOW DEVELOPS ALONG FRONT STALLED ACROSS NORTHERN GOMEX EARLY THU. THIS LOW TRACKS NORTHEAST ALONG THE FRONT...PASSING OFF THE SOUTHEAST COAST. THIS KEEPS NORTHEAST LOW LEVEL FLOW IN PLACE FOR THE DURATION OF THE EVENT. BELOW 700MB OR SO FORECAST SOUNDINGS DEPICT A SATURATED BUT VERY STABLE AIR MASS. SO WHILE MID AND UPPER LEVEL FORCING WILL BE PRESENT IT APPEARS THE LOW LEVEL STABILITY WILL ULTIMATELY WIN OUT. THUS HAVE GONE FOR LOWER POP AND MINIMAL QPF EARLY IN THE PERIOD. AS SURFACE AND MID LEVEL FEATURES MOVE OFF TO THE NORTHEAST HIGH PRESSURE BUILDS IN UNDER DEVELOPING PROGRESSIVE MID LEVEL PATTERN. THIS ALLOWS MUCH DRIER AND COOLER AIR TO SPREAD IN FROM THE WEST. PINCHED GRADIENT ALONG THE COAST WILL KEEP NORTHEAST FLOW BRISK INTO SAT MORNING...ESPECIALLY ALONG THE COAST. LATE IN THE PERIOD MEDIUM RANGE GUIDANCE IS TRYING TO SHOW A WEAK COASTAL LOW DEVELOPING ON REMAINS OF STALLED SURFACE BOUNDARY. GIVEN THE TIME RANGE AND POTENTIAL FOR SIGNIFICANT CHANGES REGARDING THIS FEATURE WILL NOT INTRODUCE A POP LATE IN THE PERIOD. TEMPS NEAR CLIMO THROUGH THE PERIOD. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 12Z...LBT IS LIFR AND WILL LIKELY NOT REACH VFR UNTIL 14Z...PERHAPS EVEN AN HOUR LATER. THE OTHER TERMINALS APPEAR TO HAVE ENOUGH SOUTHWEST FLOW TO MIX OUT A BIT EARLIER. STAGNANT SYNOPTIC PATTERN WILL KEEP THE FRONT WEST OF THE REGION...WITH MAINLY THICK HIGH CLOUDS IN AND OUT OF OUR WESTERN TERMINALS. ALONG THE COAST...GOOD LOW LEVEL MOISTURE WILL GIVE US A CHANCE OF AN MVFR CEILING IN AND OUT THROUGH EARLY AFTERNOON. SOUTHWEST FLOW WILL CONTINUE THROUGH THE OVERNIGHT HOURS. IT APPEARS THE WINDS WILL BE TOO STRONG TO SUPPORT FOG...BUT WILL REEVALUATE ON THE NEXT SET OF TAFS. EXTENDED OUTLOOK...POSSIBLE RESTRICTIONS IN ASSOCIATION WITH COLD FRONT TUESDAY AND WEDNESDAY...MAINLY AT THE INLAND TERMINALS. CHANCE FOR SHOWERS THURSDAY. OTHERWISE EXPECT VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM MONDAY...SFC PRESSURE PATTERN INDICATES THE WESTERN ATLANTIC HIGH...CENTERED OFFSHORE FROM THE SE U.S. COAST...WILL PRODUCE SSW THROUGH WSW WIND DIRECTIONS. THE SFC PG WILL SLIGHTLY TIGHTEN AS THE SFC COLD FRONT APPROACHES FROM THE NW TODAY... BEFORE STALLING BETWEEN DUCK NC SOUTHWEST TO PENSACOLA BEACH FLORIDA TONIGHT. LOOK FOR WIND SPEEDS AT 5 TO 10 KT THIS MORNING...INCREASING TO 10 TO POSSIBLY 15 KT THIS AFTERNOON AND TONIGHT. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT...EXCEPT UP TO 4 FT ACROSS THE OUTER WATERS OFF CAPE FEAR THIS AFTERNOON AND/OR TONIGHT. GENERALLY...A 1 1/2 TO 2 1/2 FOOT ESE GROUND SWELL EXHIBITING 9 TO 12 SECOND PERIODS WILL DOMINATE SIG. SEAS. THE ADDITION OF 3 TO 5 SECOND PERIOD WIND DRIVEN WAVES WILL PUSH SIG. SEAS TO THE 4 FOOT LEVEL OFF CAPE FEAR LATER TODAY AND TONIGHT. SEA FOG WILL ALSO REMAIN A THREAT TO MARINERS THIS FORECAST PERIOD...OCCASIONALLY AND BRIEFLY MOVING ONSHORE. VSBY ROUGHLY 1 NM OR LESS WITHIN THE SEA FOG. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 245 AM MONDAY...SOUTHWEST FLOW REMAINS IN PLACE FOR A MAJORITY OF THE PERIOD WITH SPEEDS GENERALLY 10 TO 15 KT. WEAK SLOW MOVING FRONT DROPPING IN FROM THE NORTH-NORTHWEST LATE IN THE PERIOD WILL BRING ABOUT A WIND SHIFT TO NORTHERLY BY THE END OF THE PERIOD BUT LACK OF COLD ADVECTION OR SIGNIFICANT GRADIENT WILL KEEP SPEEDS LIGHT...10 KT OR LESS. SEAS WILL RUN 2 TO 4 FT THROUGH THE PERIOD...MAINLY AS SOUTHERLY WIND WAVE. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 245 AM MONDAY...NORTH TO NORTHEAST FLOW THU STARTS TO INCREASE THU NIGHT...BUT QUESTION REMAINS BY HOW MUCH. WEAK LOW PRESSURE EMERGING FROM NORTHEAST GOMEX WILL PINCH GRADIENT...BUT HOW TIGHT GRADIENT BETWEEN THIS LOW AND THE HIGH BUILDING IN FROM THE NORTHWEST BECOMES IS UNCERTAIN. ALL OF THE MEDIUM RANGE GUIDANCE DEPICTS THIS SURFACE WAVE PASSING EAST OF THE WATERS LATE THU NIGHT OR EARLY FRI...SO FEEL THAT AN INCREASE IN NORTHEAST FLOW IS LIKELY FOR SECOND HALF OF THE PERIOD. AT THIS POINT CANNOT SAY IF HEADLINES WILL BE NEEDED BUT IT CERTAINLY APPEARS TO BE A POSSIBILITY. CURRENT SEAS FORECAST IS 2 TO 4 FT THU BUILDING TO 3 TO 5 ON FRI. HOWEVER IT IS WORTH NOTING THAT WW3 GUIDANCE IS COMING IN CLOSE TO 10 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ SYNOPSIS...III NEAR TERM...DCH SHORT TERM...III LONG TERM...III AVIATION...DCH/SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
636 AM EST MON JAN 14 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THE FIRST PART OF THE WORK WEEK. THIS WILL LEAD TO MAINLY DRY CONDITIONS AND MORE SEASONABLE TEMPERATURES THROUGH WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THIS AFTERNOON. AS IT DOES...NORTH TO NORTHWEST LOW LEVEL FLOW WILL DECREASE BUT WEAK CAA WILL CONTINUE THROUGH MUCH OF THE DAY. A FAIR AMOUNT OF LOW CLOUDS ARE STILL IN PLACE ACROSS THE REGION BUT SATELLITE IMAGES ARE INDICATING SOME BREAKS ACROSS PARTS OF OUR SOUTHWEST. MAIN QUESTION FOR TODAY WILL BE HOW FAST THESE CLOUDS DISSIPATE. THE RAP IS HANGING ON TO A FAIR AMOUNT OF LOW LEVEL MOISTURE THROUGH THIS AFTERNOON. THIS IS PROBABLY OVERDONE AND PREFER SOMETHING CLOSER TO WHAT THE NAM IS INDICATING ALTHOUGH THE WEAK CAA MAY HELP KEEP THE CLOUDS AROUND A BIT LONGER. WILL THEREFORE ALLOW FOR PARTIAL CLEARING HEADING THROUGH LATE MORNING INTO EARLY AFTERNOON. 500 MB MOISTURE WILL INCREASE FROM THE SOUTHWEST LATER THIS AFTERNOON AND THIS COULD ALLOW FOR AN INCREASE IN SOME HIGHER LEVEL CLOUDS LATER TODAY. WITH WEAK CAA...EXPECT HIGHS RANGING FROM THE UPPER 20S TO LOWER 30S IN THE NORTHWEST TO THE MID AND UPPER 30S ACROSS THE SOUTHEAST. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... SURFACE HIGH PRESSURE WILL REMAIN ACROSS THE AREA TUESDAY INTO WEDNESDAY...PROVIDING MAINLY DRY CONDITIONS. THE ONE EXCEPTION COULD BE ACROSS OUR FAR SOUTHEAST AS A COUPLE OF SHORT WAVES RIDE UP ALONG THE APPALACHIANS. THE MODELS HAVE TRENDED A BIT FARTHER NORTH WITH THEIR NORTHERN PERIPHERY WITH THE INITIAL WAVE TONIGHT AND THEN THE SECOND ONE FOR TUESDAY NIGHT. BOTH THE 00Z ECMWF AND GFS ARE TRYING TO BRUSH A FEW OF OUR SOUTHEASTERN COUNTIES WITH PCPN WHILE THE 00Z AND 06Z NAM ARE KEEPING EVERYTHING TO THE SOUTH. GIVEN THE TRENDS...WILL GO AHEAD AND INTRODUCE SOME POPS ACROSS THE FAR SOUTHEAST FOR TONIGHT AND TUESDAY NIGHT...BUT KEEP THEM LOW AT THIS POINT. FORECAST SOUNDINGS ARE INDICATING THE POSSIBILITY OF A RAIN/SNOW MIX WITH ANY PCPN BUT GIVEN THAT IT WOULD BE AT NIGHT...IT MAY BE MORE LIKELY TO BE SNOW THAN RAIN. CLOUDS WILL BE DEPENDENT ON JUST HOW FAR NORTH THESE WAVES MAKE IT AND THIS WILL ALSO HAVE AN AFFECT ON LOW TEMPERATURES BOTH TONIGHT AND TUESDAY NIGHT. WILL GO AHEAD AND ALLOW FOR A DECENT GRADIENT BOTH NIGHTS FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... HIGH PRESSURE BUILDS BACK INTO THE OH AND TN VALLEYS THU INTO FRI. ENERGY KEEPS RUNNING THROUGH THE SUBTLE ERN U.S. LONGWAVE TROF OVER THE WEEKEND. GFS AND ECMWF DIFFER ON THE STRENGTH OF A SYSTEM ON SATURDAY....BUT BOTH PUSH COOLER AIR IN ON SUNDAY WITH A TRAILING COLD FRONT. ONCE AGAIN THE MOISTURE IS LOOKING LIMITED FOR SUNDAY...SO KEPT THE FCST DRY. COOLER AIR BEHIND WEDNESDAYS SYSTEM WILL FILTER IN FOR THU...DROPPING HIGHS INTO 30S. THE SEE-SAW TEMPERATURES WILL CONTINUE...AS A WARMER AIR WORKS BACK IN FOR FRIDAY AND SATURDAY. HIGHS FRIDAY WILL BE IN THE UPPER 30S TO LOWER 40S...WITH 40S FOR HIGHS ON SATURDAY. TEMPERATURES WILL TAKE ANOTHER DOWN TURN ON SUNDAY AS HIGHS WILL RANGE FROM THE MID 30S IN THE N TO MID 40S IN NRN KY. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... CLOUD DECK AROUND 1000 TO 1500 FEET AGL ASSOCIATED WITH RESIDUAL LOW LEVEL MOISTURE WILL KEEP CIGS MAINLY MVFR WITH A COUPLE IFR SPOTS THROUGHOUT THE MORNING. AS THE DAY PROGRESSES THIS DECK SHOULD THIN AS DRIER AIR BEGINS TO MIX INTO THE LOW LEVELS. CURRENT FORECAST CALLS FOR CLOUDS TO SCATTER TO VFR BY THE LATE MORNING STARTING ACROSS THE SOUTHERN TERMINALS KCVG/KLUK...AND INTO THE EARLY AFTERNOON TOWARD THE NORTHERN TERMINALS. AS LOW LEVEL WINDS BEGIN TO VEER OUT OF THE NORTHEAST LATE THIS AFTERNOON...IT IS POSSIBLE THAT SOME OF THE MVFR CIGS MAY TRY TO PUSH SOUTH ACROSS THE NORTHERN TERMINALS. KEPT THE FORECAST A BIT MORE OPTIMISTIC WITH VFR CONDITIONS EXPECTED FROM THIS AFTERNOON ONWARD THROUGH THE REST OF THE TAF PERIOD. THIS EVENING...A DISTURBANCE PASSING BY TO OUR SOUTH WILL BRING VFR CLOUD COVER ACROSS THE AREA. PRECIPITATION ASSOCIATED WITH THIS DISTURBANCE IS EXPECTED TO REMAIN SOUTH OF OUR TERMINALS. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...JGL NEAR TERM...JGL SHORT TERM...JGL LONG TERM...SITES AVIATION...LATTO
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
450 AM CST MON JAN 14 2013 .DISCUSSION... FAIRLY QUIET WEEK AHEAD...WITH MAIN ENERGY FROM A COUPLE OF WAVES EXPECTED TO REMAIN NORTH OF THE AREA...LEAVING TEMPERATURES AS PRIMARY CONCERN THROUGH NEXT WEEKEND. FOR TODAY...WEAK WAVE SLIDING NORTHEAST ACROSS OUR AREA AHEAD OF MID-UPPER TROUGH DROPPING SOUTHEAST INTO THE UPPER MIDWEST. WITH COLD AIR MASS STILL IN PLACE AND WEAK LIFT FROM THIS WAVE...STILL SEEING FLURRIES BEING SQUEEZED OUT OF ANY LOWER/DEEPER MOISTURE LAYERS. RAP SEEMS TO BE HANDLING THE MOISTURE FAIRLY WELL...AND KEEPS DEEPER MOISTURE ACROSS CENTRAL/NORTHERN CWA THIS MORNING... SHIFTING EAST OF THE AREA THROUGH THE AFTERNOON. DEEPER MOISTURE AGAIN LIES IN FAVORABLE TEMPERATURE ZONE FOR ICE PRODUCTION /A FEW DEGREES EITHER SIDE OF -15C/...THUS HAVE ADDED SCATTERED FLURRIES ALONG/NORTH OF I-90 THROUGH MIDDAY. TEMPERATURES SHOULD REBOUND A BIT FROM WEEKEND CHILL AS WARMER LOW LEVEL AIR BEGINS TO WORK INTO THE AREA THIS AFTERNOON. STILL ONE MORE DAY BELOW NORMAL THOUGH... WITH HIGHS IN THE TEENS TO LOWER 20S. ONE THING OF NOTE ON TEMPS THROUGHOUT MUCH OF THE FORECAST... NAM/GFS APPEAR TO HAVE POORLY INITIALIZED SNOW COVER IN THE MODEL... WHICH SEEMS TO BE HAVING A LARGE EFFECT ON THEIR RESPECTIVE SURFACE TEMPERATURE FORECASTS... SEEN BOTH IN THE RAW MODELS/MOS OUTPUT... THOUGH SOMEWHAT LESSER EXTENT IN THE LATTER. THUS HAVE CHOSEN TO FAVOR WARMER GEM/ECMWF TEMPERATURES THROUGH MOST OF THE WEEK... ESPECIALLY THROUGH FRIDAY WHEN WARM AIR ALOFT REMAINS IN PLACE. NEXT WAVE MOVES ACROSS THE REGION TUESDAY/TUESDAY NIGHT. STRONG WARM ADVECTION WILL LEAD TO POTENTIAL FOR A LITTLE LIGHT SNOW OR FLURRIES AHEAD OF THE WARM AIR...WHICH WILL SPREAD ACROSS THE FORECAST AREA IN EARNEST TUESDAY NIGHT. LITTLE ACCUMULATION EXPECTED...WITH MAYBE A QUARTER INCH OR SO ALONG THE HIGHWAY 14 CORRIDOR. STOUT SOUTHWEST FLOW AHEAD OF THE WARM FRONT WILL RESULT IN GUSTY WINDS ATOP AND DOWNSTREAM OF THE BUFFALO RIDGE MUCH OF THE NIGHT. EXPECT EARLY EVENING LOWS FROM AROUND 20 IN THE EAST TO THE MID-UPPER 20S WEST OF THE JAMES VALLEY...WITH MOST AREAS WARMING TO NEAR FREEZING OR JUST SHY BY DAYBREAK WEDNESDAY AS WINDS TURN TO THE WEST BEHIND THE WARM FRONT. STILL LOOKS LIKE A MILD DAY WITH TEMPS ONLY WARMING A FEW MORE DEGREES THROUGH THE DAY TO HIGHS OF 35 TO 45. BACKDOOR COOL FRONT DROPS THROUGH NORTHEAST PORTIONS OF THE FORECAST AREA WEDNESDAY NIGHT/THURSDAY. TEMPERATURES STILL EXPECTED TO BE ABOVE NORMAL THURSDAY THOUGH...WITH HIGHS UPPER 20S NORTHEAST TO THE MID 30S THROUGH THE MISSOURI VALLEY. GEM/ECMWF BOTH SHOWING ANOTHER WARM PUSH FRIDAY AHEAD OF STRONGER PUSH OF COLD AIR EXPECTED NEXT WEEKEND. HAVE NUDGED TEMPERATURES A FEW DEGREES ABOVE GENERAL MODEL CONSENSUS...THOUGH COULD BE EVEN WARMER IF 14/00Z ECMWF PANS OUT. A COUPLE OF QUICK MOVING WAVES DIVE SOUTHEAST ACROSS NORTH DAKOTA AND NORTHERN MINNESOTA DURING THE LONGER RANGE. THE FIRST WEAKER WAVE MOVES THROUGH THURSDAY NIGHT...LEAVING A TIGHTENING THERMAL GRADIENT WHICH NEXT STRONGER WAVE CAN WORK WITH SATURDAY. THIS WAVE WILL PUSH THE ARCTIC FRONT SOUTH THROUGH THE REGION...BRINGING A RETURN TO BELOW NORMAL TEMPERATURES BY THE LATTER HALF OF NEXT WEEKEND. AS WAS MENTIONED ABOVE...ENERGY APPEARS TO REMAIN WELL NORTH OF OUR AREA AT THIS TIME...SO WILL KEEP THE LONGER RANGE DRY FOR NOW. HOWEVER WILL HAVE TO WATCH FOR POTENTIAL OF SOME LIGHT SNOW SUNDAY AS YET ANOTHER WAVE DROPS INTO THE ARCTIC AIR MASS WHICH IS EXPECTED TO PUSH BACK INTO THE REGION BY THEN. && .AVIATION.../FOR THE 12Z TAF ISSUANCE/ AN AREA OF CEILINGS 1-3K FEET SHOULD BE EXITING SOUTHWEST MN BY 15Z. OTHERWISE VFR IS EXPECTED OVER THE AREA THROUGH 15/12Z. AREAS OF CEILINGS 3-5K FEET WILL PASS OVER THE AREA NORTH OF INTERSTATE 90 THROUGH 15/06Z WITH CEILINGS ELSEWHERE UNRESTRICTED OR ABOVE 5K FEET. IT APPEARS AIR WILL BE TOO DRY FOR PATCHY FOG IN LIGHT WIND REGIME NEAR END OF PERIOD AT 15/12Z. SURFACE WINDS SHOULD BE 10 KNOTS OR LESS THROUGH 15/12Z. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
415 AM CST MON JAN 14 2013 .DISCUSSION... FAIRLY QUIET WEEK AHEAD...WITH MAIN ENERGY FROM A COUPLE OF WAVES EXPECTED TO REMAIN NORTH OF THE AREA...LEAVING TEMPERATURES AS PRIMARY CONCERN THROUGH NEXT WEEKEND. FOR TODAY...WEAK WAVE SLIDING NORTHEAST ACROSS OUR AREA AHEAD OF MID-UPPER TROUGH DROPPING SOUTHEAST INTO THE UPPER MIDWEST. WITH COLD AIR MASS STILL IN PLACE AND WEAK LIFT FROM THIS WAVE...STILL SEEING FLURRIES BEING SQUEEZED OUT OF ANY LOWER/DEEPER MOISTURE LAYERS. RAP SEEMS TO BE HANDLING THE MOISTURE FAIRLY WELL...AND KEEPS DEEPER MOISTURE ACROSS CENTRAL/NORTHERN CWA THIS MORNING... SHIFTING EAST OF THE AREA THROUGH THE AFTERNOON. DEEPER MOISTURE AGAIN LIES IN FAVORABLE TEMPERATURE ZONE FOR ICE PRODUCTION /A FEW DEGREES EITHER SIDE OF -15C/...THUS HAVE ADDED SCATTERED FLURRIES ALONG/NORTH OF I-90 THROUGH MIDDAY. TEMPERATURES SHOULD REBOUND A BIT FROM WEEKEND CHILL AS WARMER LOW LEVEL AIR BEGINS TO WORK INTO THE AREA THIS AFTERNOON. STILL ONE MORE DAY BELOW NORMAL THOUGH... WITH HIGHS IN THE TEENS TO LOWER 20S. ONE THING OF NOTE ON TEMPS THROUGHOUT MUCH OF THE FORECAST... NAM/GFS APPEAR TO HAVE POORLY INITIALIZED SNOW COVER IN THE MODEL... WHICH SEEMS TO BE HAVING A LARGE EFFECT ON THEIR RESPECTIVE SURFACE TEMPERATURE FORECASTS... SEEN BOTH IN THE RAW MODELS/MOS OUTPUT... THOUGH SOMEWHAT LESSER EXTENT IN THE LATTER. THUS HAVE CHOSEN TO FAVOR WARMER GEM/ECMWF TEMPERATURES THROUGH MOST OF THE WEEK... ESPECIALLY THROUGH FRIDAY WHEN WARM AIR ALOFT REMAINS IN PLACE. NEXT WAVE MOVES ACROSS THE REGION TUESDAY/TUESDAY NIGHT. STRONG WARM ADVECTION WILL LEAD TO POTENTIAL FOR A LITTLE LIGHT SNOW OR FLURRIES AHEAD OF THE WARM AIR...WHICH WILL SPREAD ACROSS THE FORECAST AREA IN EARNEST TUESDAY NIGHT. LITTLE ACCUMULATION EXPECTED...WITH MAYBE A QUARTER INCH OR SO ALONG THE HIGHWAY 14 CORRIDOR. STOUT SOUTHWEST FLOW AHEAD OF THE WARM FRONT WILL RESULT IN GUSTY WINDS ATOP AND DOWNSTREAM OF THE BUFFALO RIDGE MUCH OF THE NIGHT. EXPECT EARLY EVENING LOWS FROM AROUND 20 IN THE EAST TO THE MID-UPPER 20S WEST OF THE JAMES VALLEY...WITH MOST AREAS WARMING TO NEAR FREEZING OR JUST SHY BY DAYBREAK WEDNESDAY AS WINDS TURN TO THE WEST BEHIND THE WARM FRONT. STILL LOOKS LIKE A MILD DAY WITH TEMPS ONLY WARMING A FEW MORE DEGREES THROUGH THE DAY TO HIGHS OF 35 TO 45. BACKDOOR COOL FRONT DROPS THROUGH NORTHEAST PORTIONS OF THE FORECAST AREA WEDNESDAY NIGHT/THURSDAY. TEMPERATURES STILL EXPECTED TO BE ABOVE NORMAL THURSDAY THOUGH...WITH HIGHS UPPER 20S NORTHEAST TO THE MID 30S THROUGH THE MISSOURI VALLEY. GEM/ECMWF BOTH SHOWING ANOTHER WARM PUSH FRIDAY AHEAD OF STRONGER PUSH OF COLD AIR EXPECTED NEXT WEEKEND. HAVE NUDGED TEMPERATURES A FEW DEGREES ABOVE GENERAL MODEL CONSENSUS...THOUGH COULD BE EVEN WARMER IF 14/00Z ECMWF PANS OUT. A COUPLE OF QUICK MOVING WAVES DIVE SOUTHEAST ACROSS NORTH DAKOTA AND NORTHERN MINNESOTA DURING THE LONGER RANGE. THE FIRST WEAKER WAVE MOVES THROUGH THURSDAY NIGHT...LEAVING A TIGHTENING THERMAL GRADIENT WHICH NEXT STRONGER WAVE CAN WORK WITH SATURDAY. THIS WAVE WILL PUSH THE ARCTIC FRONT SOUTH THROUGH THE REGION...BRINGING A RETURN TO BELOW NORMAL TEMPERATURES BY THE LATTER HALF OF NEXT WEEKEND. AS WAS MENTIONED ABOVE...ENERGY APPEARS TO REMAIN WELL NORTH OF OUR AREA AT THIS TIME...SO WILL KEEP THE LONGER RANGE DRY FOR NOW. HOWEVER WILL HAVE TO WATCH FOR POTENTIAL OF SOME LIGHT SNOW SUNDAY AS YET ANOTHER WAVE DROPS INTO THE ARCTIC AIR MASS WHICH IS EXPECTED TO PUSH BACK INTO THE REGION BY THEN. && .AVIATION.../FOR THE 06Z TAF ISSUANCE/ AN AREA OF STRATUS AROUND 3000 FEET WILL AFFECT THE NORTHERN CWA THROUGH THE OVERNIGHT HOURS AFFECTING BOTH THE KHON AND KFSD TERMINALS. THERE MAYBE A FEW FLURRIES ASSOCIATED WITH THIS BAND OF STRATUS...BUT IS NOT EXPECTED TO REDUCE VISIBILITY. THEREAFTER..VFR CONDITIONS ARE EXPECTED TO PREVAIL WITH LIGHT WESTERLY WINDS BECOMING SOUTHWEST. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
949 AM CST MON JAN 14 2013 .UPDATE...MOSTLY SUNNY SKIES WILL CONTINUE THROUGH THE MORNING. COULD SEE SOME HIGH CLOUDS MOVE IN FROM THE SOUTH THIS AFTERNOON...AND AN AREA OF LOW CLOUDS MAY ALSO MOVE INTO THE NORTHWEST FORECAST AREA BY LATE AFTERNOON. OTHERWISE...A QUIET...BUT CHILLY DAY STILL EXPECTED WITH HIGHS A FEW DEGREES BELOW NORMAL. && .AVIATION/18Z TAFS/...WATCHING AN AREA OF MVFR CIGS UPSTREAM. LATEST RAP AND NAM RH FIELDS INDICATE THIS MAY HOLD TOGETHER AND MOVE INTO THE NORTHWEST HALF OF THE FORECAST AREA MID TO LATE THIS AFTERNOON. BEST CHANCE FOR THESE LOWER CIGS APPEARS TO BE ROUGHLY ALONG AND NORTHWEST OF A MINERAL POINT TO SHEBOYGAN LINE...AS THE HIGH RH IN THE MODELS NEVER QUITE MAKES IT TO THE SOUTHEAST. WILL KEEP AN EYE ON SATELLITE TRENDS AND CONSIDER ADDING SOME LOWER CIGS TO THE TAFS. ANY LOWER CIGS SHOULD SCATTER OUT OR MOVE OUT BY MORNING...WITH VFR CONDITIONS THEN EXPECTED THROUGH THE DAY TUESDAY. && .PREV DISCUSSION... /ISSUED 321 AM CST MON JAN 14 2013/ TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH. HIGH PRESSURE SLIDING INTO THE AREA WILL BRING QUIET WEATHER TO REGION. A COLD START TO THE DAY...COUPLED WITH A DECENT THERMAL TROUGH LINGERING OVER THE WESTERN GREAT LAKES MEANS TEMPS WON/T RECOVER VERY FAST TODAY. THIS WILL PROBABLY BE THE COLDEST DAY OF THE WEEK...THOUGH THURSDAY WILL CHALLENGE IT. SOME LOWER CLOUDS ASSOCIATED WITH WEAK COLD AIR ADVECTION OVER THE EASTERN DAKOTAS AND MINNESOTA MAY SNEAK INTO THE NORTHWEST CWA TOWARD EVENING. BUT THIS SHOULDN/T MAKE MUCH HEADWAY BEYOND THAT BEFORE LIFTING TO THE NORTH OR DIMINISHING AS THE CAA WEAKENS. ALSO...SOME CIRRUS MAY STREAM IN FROM THE SOUTHWEST TODAY AND TONIGHT AS A VERY STRONG UPPER LEVEL JET WILL BE CENTERED FROM OKLAHOMA NORTHEAST INTO LOWER MICHIGAN. TEMPS TONIGHT WILL BE A LITTLE TRICKY AND VERY DEPENDENT ON THE THICKNESS OF THE POSSIBLE CLOUDS. THOSE CLOUDS AREN/T A CERTAINTY...SO PLAYED IT CAUTIOUSLY. ANOTHER COLD NIGHT ON TAP BEFORE TEMPS RISE INTO THE MIDDLE OF THE WEEK. TUESDAY THROUGH WEDNESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM. SHORT TERM MODELS SHOWING 500MB FLOW WEST SOUTHWEST TUESDAY...BEFORE A SHORTWAVE TROUGH SLIDES EAST ACROSS THE REGION LATER TUESDAY AND TUESDAY EVENING. 500MB WINDS GRADUALLY VEER WEST NORTHWEST BEHIND THE SHORTWAVE TROUGH LATER TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. GFS/CANADIAN BRING A VORTICITY MAXIMUM INTO NORTHERN PORTIONS OF THE AREA WEDNESDAY NIGHT...WITH THE NAM WELL NORTH OF THE AREA WITH THIS FEATURE. THE ECMWF BRINGS THIS FEATURE IN WEDNESDAY. AT THE SURFACE...HIGH PRESSURE TO THE SOUTH OF THE AREA TUESDAY WILL SLIDE TO THE SOUTH SOUTHWEST TUESDAY NIGHT. MEANWHILE...WARM AIR ADVECTION MOVES INTO THE AREA TUESDAY NIGHT INTO WEDNESDAY...WITH STRONG LOW PRESSURE PASSING WELL NORTHEAST OF THE AREA. MODEST Q VECTOR CONVERGENCE SEEN ACROSS NORTHWESTERN AND NORTHERN PORTIONS OF THE AREA TUESDAY NIGHT INTO WEDNESDAY...THOUGH MODELS HAVE DRY TUESDAY NIGHT AND VERY LIGHT/SPOTTY QPF WEDNESDAY MORNING. AREA FORECAST SOUNDINGS TRY TO MOISTEN UP WEDNESDAY MORNING. KEPT LOW END POPS FOR WEDNESDAY MORNING IN THE FAR NORTHERN COUNTIES. PRESSURE GRADIENT GETS TIGHT TUESDAY NIGHT INTO WEDNESDAY...WHICH WILL BRING BRISK WEST WINDS. TEMPERATURES WILL MODERATE A BIT DURING THIS PERIOD. COLD FRONT SLIDES SOUTHEAST THROUGH THE AREA WEDNESDAY AFTERNOON AND EVENING...WITH THE ECMWF/CANADIAN QUICKER THAN THE GFS/NAM. CANADIAN IS MOST AGGRESSIVE MODEL WITH QPF ACROSS THE AREA DURING THIS TIME...WITH LIGHT QPF IN THE EVENING ON THE GFS...AND THE NAM/ECMWF DRY. WEAK TO MODEST UPWARD MOTION SEEN ON 850MB TO 700MB FRONTOGENESIS RESPONSE FIELDS DURING THIS TIME. KEPT SMALL CHANCES FOR LIGHT SNOW SHOWERS GOING FOR FAR NORTHERN AND NORTHEASTERN PORTIONS OF THE AREA FOR THIS TIME. GFS/ECMWF/CANADIAN SHOW STRONG COLD AIR ADVECTION AFTER THE COLD FRONTAL PASSAGE WEDNESDAY NIGHT...WITH THE NAM MUCH WARMER. TRENDED TOWARD THE COOLER SOLUTIONS FOR TEMPERATURES WEDNESDAY NIGHT. THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE IS MEDIUM. ECMWF/GFS SHOW SOME DIFFERENCES DURING THIS PERIOD ACROSS THE AREA. THEY BOTH DO SHOW WEAK HIGH PRESSURE TO THE WEST KEEPING QUIET WEATHER ACROSS THE AREA FOR THURSDAY. ECMWF THEN BRINGS A WARM FRONT ACROSS THE AREA LATE THURSDAY NIGHT WITH AN AREA OF QPF CLIPPING THE FAR NORTH...EXITING BY FRIDAY AFTERNOON. IT IS THEN DRY THROUGH SATURDAY ACROSS THE REGION. GFS KEEPS THURSDAY NIGHT DRY...WITH THE WARM FRONT THEN SETTING UP WEST TO EAST ACROSS THE FAR NORTHERN COUNTIES FRIDAY. THIS KEEPS MOST OF THE QPF JUST NORTH OF THE FORECAST AREA FRIDAY AND FRIDAY NIGHT. USED CONSENSUS POPS AND TEMPERATURES FOR THURSDAY THROUGH FRIDAY NIGHT...GIVEN THE DIFFERENCES IN THE MODELS. THE GFS THEN DEVELOPS LOW PRESSURE OVER NORTHERN LOWER MICHIGAN BY 00Z SUNDAY...WITH A STRONG COLD FRONT PUSHING SOUTHEAST THROUGH THE AREA. STRONG COLD AIR ADVECTION THEN BRINGS A VERY COLD AIRMASS INTO THE AREA FOR SATURDAY NIGHT AND SUNDAY. THE ECMWF DELAYS THIS SYSTEM UNTIL SATURDAY NIGHT. GFS CLIPS THE NORTHEASTERN HALF OF THE AREA WITH QPF SATURDAY. THE ECMWF DOES HAVE LIGHT QPF JUST MISSING THE AREA SATURDAY NIGHT WITH A PASSING VORTICITY MAXIMUM TO THE NORTH. AGAIN...USED CONSENSUS POPS AND TEMPERATURES FOR THIS PERIOD WITH THE UNCERTAINTY IN THE MODELS. AVIATION/12Z TAFS/...HIGH PRESSURE WILL BRING VFR CONDITIONS TO THE AREA THROUGH THE TAF PERIOD. JUST SOME HIGH CLOUDS MOSTLY. MARINE...A STRONG LOW PRESSURE SYSTEM PASSING JUST NORTH OF THE U.S./CANADIAN BORDER LATE TUESDAY NIGHT THROUGH WEDNESDAY WILL LIKELY RESULT IN SMALL CRAFT ADVISORY CONDITIONS DURING THIS PERIOD. EXPECT BRISK SOUTHWEST WINDS OF 15 TO 25 KNOTS VEERING WEST WITH TIME. A FEW GALE GUSTS TO 35 KNOTS WILL BE POSSIBLE. WAVES OF 3 TO 6 FEET ARE LIKELY...WITH THE HIGHEST WAVES TOWARD OPEN WATER. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...DDV TODAY/TONIGHT AND AVIATION/MARINE...DAVIS TUESDAY THROUGH SUNDAY...WOOD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
516 AM CST MON JAN 14 2013 .SHORT TERM...TODAY THROUGH WEDNESDAY 322 AM CST MON JAN 14 2013 AT 3 AM...A SURFACE TROUGH WAS LOCATED ACROSS SOUTHWEST MINNESOTA. THIS TROUGH IS CURRENTLY PRODUCING A MVFR DECK OF CLOUDS ACROSS EASTERN SOUTH DAKOTA AND SOUTHWEST MINNESOTA. THERE ARE EVEN FLURRIES BEING REPORTED AT SIOUX FALLS SOUTH DAKOTA. FURTHER TO THE SOUTHWEST...THE WATER VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH MOVING OUT OF COLORADO. THIS SYSTEM HAS BEEN PRODUCING SOME LIGHT SNOW FROM COLORADO INTO CENTRAL SOUTH DAKOTA. THE 14.00Z MODELS ARE IN GOOD AGREEMENT THAT THE SURFACE TROUGH WILL MOVE SLOWLY EAST AND GRADUALLY WEAKEN TODAY. MEANWHILE THE SHORT WAVE WILL MOVE ACROSS THE AREA THIS AFTERNOON. BOTH THE GFS AND NAM/WRF SOUNDINGS SHOW LITTLE OMEGA WITH THESE SYSTEMS. MEANWHILE THE RAP HAS UP TO 5 MICROBARS OF OMEGA CO-LOCATED WITH THE DENDRITIC GROWTH ZONE. SINCE BOTH SYSTEMS ARE CURRENTLY PRODUCING SOME FLURRIES OR VERY LIGHT SNOW...WENT MORE TOWARD THE RAP AND INTRODUCED SOME SCATTERED FLURRIES FOR THIS AFTERNOON NORTHWEST OF SAINT ANSGAR IOWA TO WISCONSIN RAPIDS LINE. ON TUESDAY NIGHT AND WEDNESDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE SYSTEM WILL MOVE ALONG THE ARCTIC COLD FRONT TO OUR NORTH. AS THE WAVE APPROACHES...THE CLOUDS WILL INCREASE OVERNIGHT AND TEMPERATURES WILL SLOWLY RISE. LIKE THE PAST COUPLE OF DAYS...THE MODELS CONTINUE TO SHOW THAT THERE WILL BE ENOUGH MOISTURE FOR SOME PRECIPITATION TO DEVELOP ALONG AND NORTH OF THE INTERSTATE 90 CORRIDOR OVERNIGHT TUESDAY AND WEDNESDAY MORNING. HOWEVER SOUNDINGS CONTINUE TO STRUGGLE ON WHETHER THERE WILL BE ICE CRYSTAL SEEDING OR NOT. IN MANY CASES...WHERE THEY SHOW THE LACK OF ICE...THERE IS NO PRECIPITATION. SINCE THERE IS NO CLEAR SIGNAL...JUST KEPT THE PRECIPITATION IN THE FORM OF SNOW FOR NOW. HOWEVER A BIT CONCERNED THAT THERE MAY BE SOME LIGHT FREEZING DRIZZLE ON THE SOUTHERN PERIPHERY OF THE PRECIPITATION. ANOTHER CONCERN ON WEDNESDAY IS THE TEMPERATURES...THE NAM/WRF HAS WAY TOO MUCH SNOW COVER IN IT. THIS MODEL SHOWED 1 TO 2 INCHES OF SNOW ON THE GROUND ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA...AND 2 TO 5 INCHES OF SNOW ACROSS WESTERN WISCONSIN. COOPERATIVE REPORTS AND NOHRSC SHOW THAT WITH THE EXCEPTION OF AN INCH AT MEDFORD WISCONSIN...MUCH OF THE AREA IS SNOW FREE. DUE TO THIS...THE NAM/WRF TEMPERATURES ARE WAY TOO COLD. TYPICALLY...AT LA CROSSE THE MID-JANUARY MAXIMUM TEMPERATURES AVERAGE 10 DEGREES WARMER THAN THE LONG TERM AVERAGE /24.7 DEGREES AT KLSE/ WHEN THERE IS NO SNOW ON THE GROUND. THIS FITS IN WELL WITH A BLEND OF THE GFS/ECMWF/GEM. WOULD NOT BE SURPRISED TO SEE SOME LOWER 40S ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY 322 AM CST MON JAN 14 2013 ON THURSDAY AND THURSDAY NIGHT...THE 14.00Z MODELS CONTINUE TO STRUGGLE ON HOW FAR SOUTH THE ARCTIC FRONT WILL GET. THE GFS HAS THIS FRONT DROPPING SOUTH OF THE FORECAST AREA. MEANWHILE THE NAM/WRF KEEPS THIS FRONT NORTH OF THE FORECAST AREA. THIS IS DUE TO ANOTHER LOW PRESSURE SYSTEM QUICKLY FOLLOWING THE LOW THAT PASSES TO THE NORTH OF THE AREA ON TUESDAY NIGHT AND WEDNESDAY. MEANWHILE THE ECMWF IS A GOOD COMPROMISE BETWEEN THE TWO AND IT HAS THIS FRONT ONLY GETTING AS FAR SOUTH AS THE INTERSTATE 94 CORRIDOR. DUE TO THESE DIFFERENCES...THERE IS LOWER THAN USUAL CONFIDENCE IN THE TEMPERATURES. EVEN THE SNOWFALL FORECAST IS UNCERTAIN DUE TO THE VARIOUS TIMING OF THE WAVES AND THE PLACEMENT OF THE FRONT /THE SNOW WILL BE MAINLY CONFINED NORTH OF THIS FRONT/. ON FRIDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE AREA WILL BE PASSING NORTH OF THE AREA. THE COMBINATION OF SOUTHWEST WINDS AND SUNSHINE WILL ALLOW TEMPERATURES TO ONCE AGAIN WARM INTO THE 30S AND LOWER 40S. THE ECMWF EVEN SUGGESTS LOWER AND MID 40S. SINCE THIS HAS BEEN A CONSISTENT SIGNAL...RAISED THE ALL BLEND TEMPERATURES BY ABOUT 5 DEGREES. ON SUNDAY...THE MODELS CONTINUE TO STRUGGLE ON HOW FAR SOUTH THE ARCTIC FRONT WILL SAG SOUTHWARD INTO THE AREA. A COUPLE OF DAYS AGO THE ECMWF CONSISTENTLY SHOWED THAT THIS FRONT WOULD MOVE WELL SOUTH OF THE AREA. THE 13.12Z ECMWF BACKED AWAY FROM THIS SOLUTION...AND THE 14.00Z ECMWF HAS RETURNED BACK TO ITS COLDER SOLUTION. SINCE THERE IS SOME UNCERTAINTY ON WHERE THIS FRONT WILL BE LOCATED AND CONCERN ABOUT HOW MUCH MODERATION MAY TAKE PLACE WITH THE LACK OF SNOW ACROSS THE AREA...JUST STAYED WITH THE ALL BLEND FORECAST FOR NOW. && .AVIATION...TODAY AND TONIGHT 515 AM CST MON JAN 14 2013 FOG PRODUCT OFF THE IR SATELLITE IS SHOWING A PATCH OF MVFR CLOUDS MOVING EAST ACROSS SOUTHERN MINNESOTA. TIMING THESE CLOUDS OFF THE SATELLITE...IT LOOKS LIKE THEY SHOULD BE INTO KRST AROUND 12Z AND BY MID MORNING FOR KLSE. THEY SHOULD THEN LAST ABOUT 6 HOURS BEFORE MOVING OFF TO THE EAST. AS WITH THE PAST FEW DAYS...SOME FLURRIES WILL LIKELY OCCUR WITH THE CLOUDS BUT NO VISIBILITY RESTRICTIONS ARE EXPECTED. A FEW CLOUDS MAY LINGER THROUGH THE AFTERNOON BEHIND THE MAIN PATCH OF CLOUDS...BUT BY EVENING AND FOR THE OVERNIGHT HOURS...THE 14.06Z NAM BUFKIT SOUNDING INDICATE SKIES SHOULD BE CLEAR WITH VFR CONDITIONS. && .ARX WATCHES/WARNINGS/ADVISORIES... 322 AM CST MON JAN 14 2013 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1015 AM PST MON JAN 14 2013 ...ONE MORE ROUND OF COOL TEMPERATURES EXPECTED... .DISCUSSION...AS OF 9:35 AM PST MONDAY...TEMPEARTURES ENDED UP COLD IN MANY SPOTS ACROSS OUR AREA...HOWEVER THE WIND CAME UP MORE THAN FORECAST FOR PARTS OF THE BAY AND THE NORTH BAY. THIS PREVENTED SOME LOCATIONS FROM DROPPING AS LOW AS THEY WERE SUNDAY MORNING. WIDESPREAD SUNSHINE CAN BE EXPECTED TODAY WITH A FEW DEGREES OF WARMING COMPARED TO YESTERDAY. GENERALLY LOW TO MID 50S INSTEAD OF UPPER 40S TO LOWER 50S WHICH WE SAW FOR SUNDAY`S HIGHS. TONIGHT WILL BE THE COOLEST NIGHT FOR THE NEXT SEVEN DAYS AS A RIDGE OF HIGH PRESSURE BUILDS BACK TO OUR AREA AND HELPS TO PUSH TEMPERATURES TO ABOVE NORMAL READINGS FOR THE SECOND HALF OF THE WEEK. TONIGHT DUE TO FAIRLY LIGHT WINDS AND CLEAR SKIES WE WILL SEE MOST LOCATIONS BACK IN THE 30S WITH A FEW 20S STILL EXPECTED FOR PARTS OF THE SOUTHERN SANTA CLARA VALLEY DOWN THROUGH THE SOUTHERN SALINAS VALLEY. WILL PROBABLY ISSUE ANOTHER FREEZE WARNING FOR THOSE LOCATIONS. WILL PROBABLY DO A MINOR UPDATE TO LOWS TONIGHT AS A FEW SHORELINE LOCATIONS LOOK TO BE A BIT TOO COOL. .PREVIOUS DISCUSSION...HAVE CANCELLED THE FROST ADVISORY FOR SAN FRANCISCO AND THE FREEZE WARNING FOR THE SAN FRANCISCO SHORELINE. THERE HAS BEEN ENOUGH WIND TO KEEP THE ATMOSPHERE MIXED...SO WHILE THE DEW PTS ARE VERY LOW TEMPERATURES WILL REMAIN A BIT WARMER THAN EXPECTED. HAVE KEPT THE FREEZE WARNING GOING TO 9 AM FOR THE INLAND VALLEYS OF THE DISTRICT AS WELL AS THE SANTA CRUZ/MONTEREY COASTLINE. THE FREEZE WARNING FOR THE NORTH BAY VALLEYS AND THE EAST BAY VALLEYS IS MARGINAL...BUT IF THE WIND DIES OFF...TEMPERATURES WILL DROP RAPIDLY IN THE VERY DRY AIRMASS. THE HRRR MODEL AND THE 00Z WRF BOTH ARE FORECASTING LIGHT SFC WINDS THIS MORNING...SO WE WILL SEE HOW THIS PANS OUT. DRY WEATHER WILL BE THE RULE FOR THE UPCOMING WEEK. A STRONG RIDGE...CLEARLY SEEN ON WATER VAPOR IMAGERY IS CENTERED AROUND 140W...WITH THE RIDGE REACHING INTO ALASKA. INTERESTING TO NOTE HOW FAR NORTH WARM AIR IS BEING ADVECTED INTO ALASKA...FAIRBANKS IS CURRENTLY A (RELATIVELY) BALMY 28 DEGREES...WHEREAS THE AVERAGE LOW IS -14 DEGREES! IN FACT...SAN MARTIN (BETWEEN MORGAN HILL AND GILROY) IS THE SAME TEMPERATURE AS FAIRBANKS AT THIS TIME...VERY RARELY SEEN IN THE MIDDLE OF JANUARY! THE RIDGE WILL SLOWLY EDGE EAST...TO A POSITION ALONG THE COAST BY THURSDAY...THEN REMAIN OVER THE WEST COAST RIGHT THROUGH THE WEEKEND. AFTER ANOTHER COLD NIGHT TONIGHT...DEPENDING ON THE WIND...TEMPERATURES WILL SLOWLY WARM THE REMAINDER OF THE WEEK AND INTO THE WEEKEND. BOTH THE GFS AND ECMWF BEGIN TO BREAK DOWN THE RIDGE BY THE MIDDLE OF NEXT WEEK (JANUARY 23). && .AVIATION...AS OF 10:15 AM PST MONDAY...CLEAR SKIES AND OFFSHORE FLOW WILL CONTINUE ACROSS AREA TERMINALS TODAY AS HIGH PRESSURE CONTINUES TO BUILD INTO THE GREAT BASIN. THE DRY AIRMASS WILL MAINTAIN VFR CONDITIONS THROUGH THE FORECAST PERIOD. HIGH CONFIDENCE. VICINITY OF KSFO...VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. EASTERLY WINDS WILL CONTINUE THROUGH EARLY THIS MORNING BECOMING VARIABLE IN THE AFTERNOON. LIGHT OFFSHORE FLOW EXPECTED OVERNIGHT. MODERATE CONFIDENCE IN REGARDS TO WINDS. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR CONDITIONS EXPECTED THROUGH THE FORECAST PERIOD. OFFSHORE FLOW WILL BECOME VARIABLE THIS AFTERNOON WITH EASTERLY WINDS ANTICIPATED TO RETURN TONIGHT. && .CLIMATE...HERE ARE THE RECORD LOW TEMPERATURES FOR JANUARY 14TH AT SELECTED LOCATIONS... SAN FRANCISCO BAY AREA .LOCATION....................JAN 14 SANTA ROSA.................21/1963 KENTFIELD..................25/1949 SAN RAFAEL.................28/2007 NAPA.......................24/1963 SAN FRANCISCO..............29/1888 SFO........................31/1963 OAKLAND....................33/2007 OAKLAND AIRPORT............28/2007 RICHMOND...................31/1955 LIVERMORE..................21/1963 MOUNTAIN VIEW..............28/2007 SAN JOSE...................28/1997 GILROY.....................19/1963 MONTEREY BAY AREA .LOCATION....................JAN 14 MONTEREY...................30/1997 SANTA CRUZ.................22/1963 SALINAS....................24/2007 SALINAS AIRPORT............25/2007 KING CITY..................17/2007 && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: STROBIN AVIATION/MARINE: CW CLIMATE: HENDERSON/BELL VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
941 AM PST MON JAN 14 2013 ...ONE MORE ROUND OF COOL TEMPERATURES EXPECTED... .DISCUSSION...AS OF 9:35 AM PST MONDAY...TEMPEARTURES ENDED UP COLD IN MANY SPOTS ACROSS OUR AREA...HOWEVER THE WIND CAME UP MORE THAN FORECAST FOR PARTS OF THE BAY AND THE NORTH BAY. THIS PREVENTED SOME LOCATIONS FROM DROPPING AS LOW AS THEY WERE SUNDAY MORNING. WIDESPREAD SUNSHINE CAN BE EXPECTED TODAY WITH A FEW DEGREES OF WARMING COMPARED TO YESTERDAY. GENERALLY LOW TO MID 50S INSTEAD OF UPPER 40S TO LOWER 50S WHICH WE SAW FOR SUNDAY`S HIGHS. TONIGHT WILL BE THE COOLEST NIGHT FOR THE NEXT SEVEN DAYS AS A RIDGE OF HIGH PRESSURE BUILDS BACK TO OUR AREA AND HELPS TO PUSH TEMPERATURES TO ABOVE NORMAL READINGS FOR THE SECOND HALF OF THE WEEK. TONIGHT DUE TO FAIRLY LIGHT WINDS AND CLEAR SKIES WE WILL SEE MOST LOCATIONS BACK IN THE 30S WITH A FEW 20S STILL EXPECTED FOR PARTS OF THE SOUTHERN SANTA CLARA VALLEY DOWN THROUGH THE SOUTHERN SALINAS VALLEY. WILL PROBABLY ISSUE ANOTHER FREEZE WARNING FOR THOSE LOCATIONS. WILL PROBABLY DO A MINOR UPDATE TO LOWS TONIGHT AS A FEW SHORELINE LOCATIONS LOOK TO BE A BIT TOO COOL. .PREVIOUS DISCUSSION...HAVE CANCELLED THE FROST ADVISORY FOR SAN FRANCISCO AND THE FREEZE WARNING FOR THE SAN FRANCISCO SHORELINE. THERE HAS BEEN ENOUGH WIND TO KEEP THE ATMOSPHERE MIXED...SO WHILE THE DEW PTS ARE VERY LOW TEMPERATURES WILL REMAIN A BIT WARMER THAN EXPECTED. HAVE KEPT THE FREEZE WARNING GOING TO 9 AM FOR THE INLAND VALLEYS OF THE DISTRICT AS WELL AS THE SANTA CRUZ/MONTEREY COASTLINE. THE FREEZE WARNING FOR THE NORTH BAY VALLEYS AND THE EAST BAY VALLEYS IS MARGINAL...BUT IF THE WIND DIES OFF...TEMPERATURES WILL DROP RAPIDLY IN THE VERY DRY AIRMASS. THE HRRR MODEL AND THE 00Z WRF BOTH ARE FORECASTING LIGHT SFC WINDS THIS MORNING...SO WE WILL SEE HOW THIS PANS OUT. DRY WEATHER WILL BE THE RULE FOR THE UPCOMING WEEK. A STRONG RIDGE...CLEARLY SEEN ON WATER VAPOR IMAGERY IS CENTERED AROUND 140W...WITH THE RIDGE REACHING INTO ALASKA. INTERESTING TO NOTE HOW FAR NORTH WARM AIR IS BEING ADVECTED INTO ALASKA...FAIRBANKS IS CURRENTLY A (RELATIVELY) BALMY 28 DEGREES...WHEREAS THE AVERAGE LOW IS -14 DEGREES! IN FACT...SAN MARTIN (BETWEEN MORGAN HILL AND GILROY) IS THE SAME TEMPERATURE AS FAIRBANKS AT THIS TIME...VERY RARELY SEEN IN THE MIDDLE OF JANUARY! THE RIDGE WILL SLOWLY EDGE EAST...TO A POSITION ALONG THE COAST BY THURSDAY...THEN REMAIN OVER THE WEST COAST RIGHT THROUGH THE WEEKEND. AFTER ANOTHER COLD NIGHT TONIGHT...DEPENDING ON THE WIND...TEMPERATURES WILL SLOWLY WARM THE REMAINDER OF THE WEEK AND INTO THE WEEKEND. BOTH THE GFS AND ECMWF BEGIN TO BREAK DOWN THE RIDGE BY THE MIDDLE OF NEXT WEEK (JANUARY 23). && .AVIATION...AS OF 3:15 AM PST MONDAY...VERY DRY AIRMASS IN PLACE THIS MORNING WITH CLEAR SKIES AND VFR CONDITIONS. CURRENT TAF PACKAGE WILL CONTINUE VFR THROUGH THE FORECAST PERIOD. ONLY TRICKY PART ARE THE EASTERLY WINDS...ESP AROUND SAN FRANCISCO BAY. CONF HIGH. VICINITY OF KSFO...VFR CONDITIONS. WINDS AS OF 11Z ARE SE AROUND THE BAY. WILL KEEP SE PREVAILING...BUT MODEL GUIDANCE SUGGESTS A NE FLOW AROUND 10 KT LATER THIS MORNING. CONF IS MARGINAL AND WILL LEAVE THE NE FLOW OUT FOR NOW. WILL MONITOR AND AMEND SFO IF NEEDED. OTHERWISE...NW FLOW LATER TODAY. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR CONDITIONS. && .CLIMATE...HERE ARE THE RECORD LOW TEMPERATURES FOR JANUARY 14TH AT SELECTED LOCATIONS... SAN FRANCISCO BAY AREA .LOCATION....................JAN 14 SANTA ROSA.................21/1963 KENTFIELD..................25/1949 SAN RAFAEL.................28/2007 NAPA.......................24/1963 SAN FRANCISCO..............29/1888 SFO........................31/1963 OAKLAND....................33/2007 OAKLAND AIRPORT............28/2007 RICHMOND...................31/1955 LIVERMORE..................21/1963 MOUNTAIN VIEW..............28/2007 SAN JOSE...................28/1997 GILROY.....................19/1963 MONTEREY BAY AREA .LOCATION....................JAN 14 MONTEREY...................30/1997 SANTA CRUZ.................22/1963 SALINAS....................24/2007 SALINAS AIRPORT............25/2007 KING CITY..................17/2007 && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...NONE. $$ PUBLIC FORECAST: STROBIN AVIATION/MARINE: MM CLIMATE: HENDERSON/BELL VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.SANFRANCISCOBAYAREA.GOV WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
355 PM MST MON JAN 14 2013 .SHORT TERM...ELONGATED UPPER TROUGH CURRENTLY MOVING ACROSS STATE. LATEST RUC QG VERTICAL VELOCITY ANALYSIS SHOWING SOME LINGERING MID LEVEL ASCENT ACROSSS FAR EASTERN PLAINS. CURRENT SURFACE OBS AND WEB CAMS DO NOT SHOW SNOW OVER THE AREA THOUGH LATEST SATELLITE INDICATE A DECENT BATCH OF LOW CLOUDS. ACROSS MOUNTAINS...WEB CAMS SHOW LIGHT SNOW ALONG THE CONTINENTAL DIVIDE AND PERHAPS OVER THE GORE AND PARK RANGES OF WESTERN JACKSON COUNTY. MODELS SHOW THE ASCENT MOVING INTO KANSAS DURING THE EVENING...SHOULD SEE ANY LINGERING SNOW ACROSS THE PLAINS ENDING AT THAT TIME. MOISTURE DOES INCREASE OVER MOUNTAINS ON BACK SIDE OF TROUGH OVERNIGHT...SHOULD SEE SNOW CHANCES INCREASE PARTICULARLY ZONE 31. WINDS LOOK TO INCREASE AS WELL OVER THE RIDGES WHICH SHOULD HELP MODERATE THE TEMPERATURES IN AND NEAR FOOTHILLS. WIND CHILL READINGS TO BE WELL BELOW ZERO...BUT SHOULD REMAIN BELOW WARNING CRITERIA. OTHERWISE...A COLD NIGHT IS EXPECTED WITH TEMPERATURES SIMILAR TO THIS MORNINGS READINGS. ON TUESDAY...THE TROUGH WILL BE IN KANSAS BY 18Z WITH NORTHERLY FLOW ALOFT OVER COLORADO. THIS SHOULD CONTINUE TO PROVIDE A CHANCE OF SNOW TO THE MOUNTAINS... MAINLY ZONES 31 AND 33. SNOW AMOUNTS TO REMAIN LIGHT. ACROSS PLAINS...DRY CONDITIONS TO PREVAIL WITH A GRADUAL INCREASE IN MID LEVEL CLOUDS. GRADUAL WARMING TREND IS EXPECTED AS WARM AIR ADVECTS INTO AREA. HOWEVER...INVERSIONS WILL LIMIT WARMUP IN MOUNTAIN VALLEYS AND LOW LYING AREAS OF THE PLAINS. ALSO MID LEVEL CLOUDS WILL HINDER WARMUP. CURRENT TEMPERATURE GRIDS LOOK REASONABLE. .LONG TERM...THE STRONG NORTH-NORTHEASTERLY FLOW ALOFT IS ON THE DECREASE TUESDAY NIGHT. ON WEDNESDAY...THE FLOW ALOFT CONTINUES TO WEAKEN AND BECOMES NORTHWESTERLY. VERY WEAK WEST-NORTHWESTERLY FLOW ALOFT IS PROGGED WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. THERE IS BENIGN SYNOPTIC SCALE ENERGY PROGGED ON THE QG VERTICAL VELOCITY FIELDS THROUGH THE FIVE PERIODS. THE LEVEL FLOW WILL LIKELY BE A MIX OF NORMAL DIURNAL TRENDS WITH SOME NORTHWESTERLY DOWNSLOPING THROWN IN TUESDAY NIGHT INTO WEDNESDAY EVENING. NORMALS PATTERNS ARE LIKELY BY THURSDAY AND THURSDAY NIGHT. FOR MOISTURE...IT IS PRETTY DEEP TUESDAY EVENING...THEN MOISTURE DECREASES TOWARDS WEDNESDAY MORNING. FROM WEDNESDAY THROUGH THURSDAY NIGHT THERE IS VERY LITTLE MOISTURE OVER THE CWA. THERE IS A TAD OF MEASURABLE SNOWFALL PROGGED ON THE QPF FIELDS TUESDAY EVENING...THEN NOTHING THROUGH THE REST OF THE PERIODS. FOR POPS WILL GO WITH 20-50%S FOR THE MOUNTAINS TUESDAY NIGHT...AND 5-20%S FOR THE PLAINS. FROM WEDNESDAY ONWARD NO POPS. FOR TEMPERATURES ...WEDNESDAY`S HIGHS ARE UP 7-9 C FROM TUESDAY`S. THURSDAY`S HIGHS ARE SIMILAR TO WEDNESDAY`S. FOR THE LATER DAYS...FRIDAY THROUGH MONDAY...THE MEDIUM RANGE MODELS KEEP THE FORECAST AREA IN...MOSTLY...WEAK NORTHWESTERLY FLOW ALOFT ALL FOUR DAYS. A MEAN TROUGH EAST OF THE CWA GETS A LITTLE CLOSER TO THE CWA...COMPARED TO PREVIOUS RUNS. THE GFS BRINGS A COLDER AIRMASS INTO THE CWA SATURDAY AND SUNDAY...THE ECMWF DOES NOT. BOTH MODELS KEEP THE CWA DRY. && .AVIATION...CEILINGS HAVE SCATTERED OUT AT DEN THOUGH SOME HAZE STILL IN THE AREA. VFR CONDITIONS TO PREVAIL WITH UNLIMITED CEILINGS. LIGHT NORTHERLY WINDS TO BECOME SOUTHERLY AS DRAINAGE PATTERN DEVELOPS. ANY FOG THAT DEVELOPS SHOULD BE CONFINED TO THE LOW LYING AREAS IN WELD COUNTY. ON TUESDAY...WINDS TO BECOME NORTHWEST WITH SPEEDS LESS THAN 8 KTS. GRADUAL INCREASE IN MID LEVEL CLOUDS WITH CEILINGS ABOVE 10000 FEET. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....RJK AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
150 PM EST MON JAN 14 2013 .SYNOPSIS (REST OF TODAY THROUGH TUESDAY)... 18Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A CONTINUED HIGHLY AMPLIFIED UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS. PATTERN IS DOMINATED BY A LARGE AND IMPRESSIVE LONGWAVE TROUGH COVERING ALMOST THE ENTIRE CONUS. THE LAST DOMAIN OF THE ONCE PROMINENT UPPER RIDGE ALONG THE EAST COAST IS ACROSS THE FAR SOUTHEASTERN STATES. LUCKILY...THIS INCLUDES US AND WILL ALLOW OUR GENERALLY DRY AND WARM WEATHER TO CONTINUE FOR ANOTHER COUPLE OF DAYS. UPPER LEVEL JET AND HIGH LEVEL MOISTURE AXIS IS LOCATED WELL OFF TO OUR NORTHWEST THIS AFTERNOON...AND HENCE WE ARE NOT SEEING THE HIGH LEVEL CIRRUS COMPARED TO WHAT OCCURRED ON SUNDAY. HOWEVER...SIMILAR TO PREVIOUS DAYS...WE HAVE SEEN THE DEVELOPMENT OF A SCT-BKN SHALLOW CU FIELD WITHIN THE SOUTHEAST LOW LEVEL FLOW. && .SHORT TERM (TONIGHT THROUGH WEDNESDAY NIGHT)... TONIGHT THROUGH TUESDAY NIGHT... MORE OF THE SAME FOR TONIGHT INTO TUESDAY AS THE STACKED RIDGING HOLDS ON JUST A LITTLE BIT LONGER. STATIC SYNOPTIC PATTERNS GENERALLY YIELD STATIC WEATHER. THIS FORECAST WILL REFLECT THAT PHILOSOPHY WITH SOME PATCHY FOG AND LOW CLOUDS DURING THE LATE NIGHT / EARLY MORNING HOURS OF TUESDAY...THEN HAVING ANY FOG BURN OFF BY AROUND 900 AM. AFTERNOON TEMPS WILL CLIMB TO WITHIN A FEW DEGREES OF 80 INLAND...AND A FEW DEGREES COOLER AT THE BEACHES WITH AN ONSHORE AFTERNOON BREEZE. AREAS OF EARLY MORNING LOW CLOUDS WILL BURN OFF QUICKLY AND BE REPLACED A FEW HOURS LATER BY ANOTHER SCT-BKN LOW LEVEL CU FIELD. WEDNESDAY/WEDNESDAY NIGHT... THE APPROACH OF A SERIES OF UPPER LEVEL IMPULSES WILL FINALLY BEGIN TO PUSH THE UPPER RIDGE TO THE EAST OF THE REGION LATER WEDNESDAY AND WEDNESDAY NIGHT ALONG WITH A SLOW WEAKENING OF THE SURFACE RIDGE. OVERALL THE WEATHER FOR WEDNESDAY WILL STILL BE GENERALLY FAIR AND WARM...BUT CHANGES TO THIS STATIC PATTERN WILL NOT BE FAR AWAY...AND BE ON THE APPROACH. INITIAL PUSH SYNOPTIC PUSH ON WEDNESDAY WILL FAIL TO PUSH THE FRONT THROUGH OUR REGION...AND WILL STALL IT JUST TO OUR NORTH. THE NEXT STRONGER PIECE OF ENERGY MOVING ALONG THE NORTHERN GULF COAST WILL HOWEVER DO THE TRICK AND PROPEL THE BOUNDARY THROUGH THE AREA THURSDAY AND/OR THURSDAY NIGHT. && .LONG TERM (THURSDAY THROUGH SUNDAY)... U/L LOW OVER THE SOUTHERN PLAINS WILL OPEN UP AND LIFT NORTHEAST ACROSS THE LOWER MISSISSIPPI VALLEY AND SOUTHEAST U.S. THURSDAY. AN ASSOCIATED COLD FRONT WILL PUSH EAST AND APPROACH WEST CENTRAL FLORIDA LATE THURSDAY AND THURSDAY NIGHT. MAIN U/L ENERGY WILL REMAIN WELL NORTH OF THE REGION WITH ONLY A CHANCE OF SHOWERS WITH THE FRONT. COOLER AIR WILL ADVECT OVER THE FORECAST AREA THURSDAY NIGHT AND FRIDAY. THE COLD FRONT WILL STALL ACROSS SOUTH FLORIDA AS IT BECOMES PARALLEL TO THE U/L FLOW FRIDAY AND FRIDAY NIGHT. THIS WILL KEEP SKIES MOSTLY CLOUDY ACROSS THE REGION WITH A SLIGHT CHANCE OF A SHOWER. THE FRONT WILL GRADUALLY RETURN NORTH AS A WARM FRONT SATURDAY WITH A WEAK SURFACE LOW POSSIBLY DEVELOPING ALONG THE FRONTAL BOUNDARY EAST OF FLORIDA SUNDAY. THIS WILL CONTINUE THE MOSTLY CLOUDY SKIES AND A SLIGHT CHANCE OF SHOWERS INTO EARLY SATURDAY...WITH DECREASING CLOUDINESS SATURDAY AS THE SURFACE LOW LIFTS NORTHEAST OF THE AREA. && .AVIATION... VFR FOR THE REST OF TODAY WITH SOME LOCAL CEILINGS AROUND 4000 FEET AT TIMES. FOG DEVELOPS AGAIN OVERNIGHT BUT THINK MOST TERMINALS STAY VFR. SOME IFR OR EVEN LIFR POSSIBLE 09Z TO 13Z TUESDAY AT PGD AND LAL. && .MARINE... HIGH PRESSURE NORTH OF THE BAHAMAS WILL CONTINUE TO RIDGE BACK TO THE WEST ACROSS THE FLORIDA PENINSULA AND EASTERN GULF OF MEXICO THROUGH WEDNESDAY. A COLD FRONT WILL THEN CROSS THE FORECAST WATERS DURING THURSDAY WITH A WIND SHIFT TO THE NORTH IN ITS WAKE BY THURSDAY NIGHT AND FRIDAY. A PERIOD OF CAUTIONARY TO ADVISORY LEVEL WINDS AND SEAS WILL ALSO BE POSSIBLE IN THE WAKE OF THIS FRONT. && .FIRE WEATHER... HIGH PRESSURE WILL CONTINUE TO DOMINATE THE LOCAL WEATHER THROUGH THE MIDDLE OF THE WEEK. DAYTIME HIGH TEMPERATURES WILL REMAIN ABOVE NORMAL...HOWEVER PLENTY OF LOW LEVEL MOISTURE WILL PREVENT ANY SIGNIFICANT FIRE WEATHER CONCERNS. A COLD FRONT WILL CROSS THE AREA LATE IN THE WEEK WITH CHANCES FOR A FEW SHOWERS AND FOLLOWED BY A MORE SEASONABLE AIRMASS BY THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... TPA 64 79 64 78 / 0 0 0 0 FMY 62 81 62 82 / 0 0 0 10 GIF 57 81 58 82 / 0 0 0 0 SRQ 61 78 59 77 / 0 0 0 0 BKV 54 80 54 81 / 0 0 0 10 SPG 65 77 64 78 / 0 0 0 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA AVIATION...JILLSON LONG TERM...OGLESBY
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
322 PM EST MON JAN 14 2013 .UPDATE... THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 320 PM EST MON JAN 14 2013 QUIET WEATHER IS EXPECTED FOR MUCH OF THE PERIOD WITH TEMPERATURES RETURNING TO NORMAL FOR THIS TIME OF YEAR UNDER HIGH PRESSURE. BY THE END OF THE LONG TERM THOUGH A CLIPPER SYSTEM COULD MOVE THROUGH BRINGING CHANCES FOR SNOW AND COLDER TEMPERATURES WITH IT. && .NEAR TERM /TONIGHT/... ISSUED AT 320 PM EST MON JAN 14 2013 CURRENTLY RADAR MOSAIC SHOWS SOME WEAK ECHOES TO THE SOUTH AND WEST THAT ARE MOVING NORTHEAST...BUT NO PRECIPITATION IS BEING REPORTED AT THE GROUND UNDER ANY OF THESE ECHOES AND WITH VERY DRY AIR ALOFT IN THE SOUNDINGS DO NOT EXPECT TO SEE ANY OF THIS REACH THE GROUND. SATELLITE SHOWS MOSTLY CLOUDY SKIES ACROSS THE AREA AND TEMPERATURES ARE IN THE LOW TO MID 20S WITH LIGHT NORTHERLY WINDS. HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST DURING THE OVERNIGHT. COMBINATION OF STRATOCU AND MID LEVEL CLOUDS WILL HAVE THE AREA STARTING OUT MOSTLY CLOUDY BUT THESE CLOUDS SHOULD THIN AND SCATTER OUT FROM NORTHWEST TO SOUTHEAST BY MORNING. GUIDANCE TEMPERATURES WERE A BIT WARMER THAN LOWS WERE LAST NIGHT AND WITH COLDER SURFACE/925MB/850MB TEMPERATURES AND SIMILAR CLOUD COVER SEE NO REASON FOR THIS TO BE TRUE. THUS ADJUSTED TEMPERATURES DOWN A FEW DEGREES FROM GUIDANCE TO BE A DEGREE OR TWO LOWER THAN LAST NIGHT. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... ISSUED AT 320 PM EST MON JAN 14 2013 QUIET WEATHER IS EXPECTED OVER THE SHORT TERM AS HIGH PRESSURE REMAINS THE DOMINANT FEATURE OVER CENTRAL INDIANA. AT THIS TIME IT LOOKS LIKE THE AREA WILL BE IN BETWEEN A LOW PRESSURE SYSTEM COMING OUT OF THE GULF AND TO VIRGINIA WHILE A CLIPPER MOVES ACROSS THE GREAT LAKES FROM TUESDAY THROUGH WEDNESDAY NIGHT. THESE SYSTEMS COULD INCREASE CLOUDS A BIT IN THE SOUTH AND NORTH RESPECTIVELY BUT THE SURFACE HIGH OVER THE AREA SHOULD KEEP CENTRAL INDIANA DRY. FOR TEMPERATURES GENERALLY USED A GUIDANCE CONSENSUS WHICH ALLOWED FOR A LITTLE WARMING TUESDAY THROUGH WEDNESDAY NIGHT WITH SLIGHTLY COOLER HIGHS ON THURSDAY AFTER THE PASSAGE OF THE CLIPPER TO THE NORTH. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... ISSUED AT 252 PM EST MON JAN 14 2013 FOCUS OF THE EXTENDED PERIOD REMAINS ON A TRANSITION TO MUCH COLDER AIR ACROSS THE REGION AS THE POLAR VORTEX DIVES INTO EASTERN CANADA AND SERVES TO AMPLIFY THE UPPER TROUGH OVER THE EASTERN PART OF THE COUNTRY. DRY WEATHER AND LARGELY SEASONABLE TEMPS WILL CONTINUE THROUGH SATURDAY AS NORTHWEST FLOW ALOFT PERSISTS ACROSS THE OHIO VALLEY. HIGHS IN THE 30S FRIDAY WILL WARM INTO THE 40S SATURDAY AS BRIEF WARM ADVECTION DEVELOPS AHEAD OF A STRONG WAVE MOVING INTO THE GREAT LAKES. MODEL CONSENSUS TRACKS THE SURFACE WAVE TO THE NORTH OF THE REGION SATURDAY NIGHT...WITH THE MAIN IMPACTS TO CENTRAL INDIANA BEING AN INCREASE IN WINDS AND A WINDSHIFT AS THE INITIAL SHOT OF COLDER AIR ADVECTS INTO THE AREA. THIS WILL BE FOLLOWED BY A CLIPPER-LIKE SYSTEM FOR MONDAY...USHERING IN A REINFORCING AND COLDER AIRMASS AS A PIECE OF OF THE POLAR VORTEX DIVES INTO THE GREAT LAKES. WHILE MODELS ARE NOT PICKING UP ON A LOT OF MOISTURE WITH THE CLIPPER...EXPECT SNOW SHOWERS TO ACCOMPANY THE SYSTEM AND HAVE INCLUDED CHANCE POPS SUNDAY NIGHT AND MONDAY. 850MB TEMPS BELOW -20C CONTINUE TO SHOW UP OVER THE FORECAST AREA ON BOTH THE OP GFS AND ECMWF BY MONDAY/TUESDAY. AT THIS POINT HAVE HIGHS FALLING INTO THE LOWER/MID 20S BY MONDAY. NOT OUT OF THE QUESTION THAT IF THESE 850MB TEMPS ARE REALIZED THAT HIGHS COULD CONCEIVABLY BE EVEN COLDER EARLY NEXT WEEK. && .AVIATION /DISCUSSION FOR THE 14/21Z TAF UPDATE/... ISSUED AT 316 PM EST MON JAN 14 2013 LOW CLOUDS HAVE SCATTERED AT ALL SITES BUT LAF...AND HAVE UPDATED TAFS TO REFLECT THIS. PREVIOUS DISCUSSION FOLLOWS. ISSUED AT 1222 PM EST MON JAN 14 2013 MVFR CEILINGS LIKELY TO PERSIST THROUGH THE AFTERNOON...AND POSSIBLY TO SOME DEGREE TONIGHT. THE COMBINATION OF COLD ADVECTION...GOOD LAPSE RATES AND VEERING N/NE FLOW IN THE LOWER LEVELS HAS ENABLED CEILINGS AROUND 1500FT TO REDEVELOP AND EXPAND BACK INTO CENTRAL INDIANA EARLY THIS AFTERNOON. WITH MOISTURE INCREASING A BIT THROUGH THE BOUNDARY LAYER...EXPECT MVFR CEILINGS TO MAINTAIN TO SOME DEGREE FOR THE REST OF THE AFTERNOON. IN ADDITION TO THE STRATOCU...FAIRLY DENSE CANOPY OF MID LEVEL CLOUDS WILL MOVE ACROSS THE OHIO VALLEY IN FAT SOUTHWEST FLOW ALOFT. NORTHERLY WINDS WILL BE LESS THAN 10KTS THROUGH SUNSET. CLOUD FORECAST TONIGHT HAS SOME UNCERTAINTY AS RAP SOUNDINGS INDICATING SHALLOW LAYER OF LOW LEVEL MOISTURE PERSISTING. WHILE FLOW THROUGH 925MB WEAKENS...IT REMAINS FROM THE NORTHEAST INTO THE OVERNIGHT. HAVE INTRODUCED SCATTERED CEILINGS AT 1500FT TONIGHT AND WILL ADJUST AS NECESSARY. MID LEVEL CLOUDS WILL CONTINUE TO MOVE ACROSS THE REGION IN THE SOUTHWEST FLOW AS WELL. SHOULD FINALLY SEE MOSTLY CLEAR SKIES BY TUESDAY MORNING AS CENTER OF HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY WITH DEEPER SUBSIDENCE NOTED IN THE MODEL SOUNDINGS. WINDS WILL VEER TO THE NORTHEAST AND REMAIN AT 10KTS OR LESS. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CP NEAR TERM...CP SHORT TERM...CP LONG TERM....RYAN AVIATION...RYAN/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
316 PM EST MON JAN 14 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 308 AM EST MON JAN 14 2013 HIGH PRESSURE WILL BUILD FROM THE PLAINS TO THE LOWER GREAT LAKES AND OHIO VALLEY ALLOWING FOR A DRY FORECAST THROUGH SUNDAY. BELOW NORMAL TEMPERATURES TO START THE WEEK WILL BECOME SEASONABLE BY MIDWEEK. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1106 AM EST MON JAN 14 2013 SATELLITE AT 11 AM SHOWS PARTLY CLOUDY SKIES ACROSS MOST OF CENTRAL INDIANA WITH A BIT MORE CLOUD COVERAGE IN THE NORTHEAST. EXPECT PARTLY CLOUDY TO BE THE RULE FOR THE REST OF THE DAY. GOING FORECAST HIGHS IN THE MID 20S TO LOW 30S LOOK RIGHT ON TRACK. PREVIOUS DISCUSSION FOLLOWS... MAIN FOCUS TODAY WILL BE ON CLEARING AS STRATOCU DECK WAS CURRENTLY DROPPING SOUTHEAST ACROSS THE EASTERN HALF OF CENTRAL INDIANA BEHIND A DEPARTING COLD FRONT ACROSS THE APPALACHIANS. MODELS IN GOOD AGREEMENT ON PLAINS HIGH PRESSURE BUILDING IN ACROSS THE FORECAST AREA. MODEL TIME SECTIONS AND SOUNDINGS ARE ALSO SHOWING THINNING OF THE LOW LEVEL MOISTURE ASSOCIATED WITH THE STRATOCU DECK...AND SATELLITE TRENDS SUGGEST THEY WILL DEPART TO THE SOUTHEAST DESPITE WHAT 00Z MOS WAS SUGGESTING. MEANWHILE...UPPER WAVE IN FAST SOUTHWEST FLOW ALOFT COULD BRING SOME INCREASED CLOUD COVER LATE TO THE SOUTHEAST COUNTIES. DRY DAY SHOULD ALLOW AREA CREEKS AND STREAMS TO DROP BELOW FLOOD STAGE AS THEY EMPTY INTO THE MAIN RIVERS WITH MINOR TO MODERATE FLOODING ON MOST FORECAST POINTS. 00Z MOS TEMPERATURES AND ALLBLEND MATCH UP PRETTY WELL AND LOOK REASONABLE CONSIDERING THE NORTHWEST COLD ADVECTION. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 308 AM EST MON JAN 14 2013 MODELS AGREE HIGH PRESSURE AND LIMITED MOISTURE SHOULD ALLOW FOR LITTLE CLOUD COVER THROUGH THE SHORT TERM. SHOULD ONLY SEE SOME INCREASE IN CLOUDS SOUTH LATE TUESDAY AS AN INVERTED TROUGH SLIDES ACROSS THE SOUTHEASTERN STATES AND SOME INCREASE IN CLOUDS NORTH LATE WEDNESDAY AS A COLD FRONT DROPS SOUTH TO THE LOWER GREAT LAKES. LOW LEVEL FLOW IS EXPECTED TO VEER TO THE NORTH TONIGHT...NORTHEAST ON TUESDAY AND SOUTHWEST BY WEDNESDAY. THIS WILL ALLOW TEMPERATURES TO WARM TO THE MID 30S NORTH AND LOWER 40S SOUTH PER SIMILAR 00Z MOS AND ALLBLEND BY WEDNESDAY. THE DRY WEATHER WILL ALLOW MINOR TO MODERATE RIVER FLOODING TO RUN ITS COURSE WITHOUT ANY HITCHES. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... ISSUED AT 252 PM EST MON JAN 14 2013 FOCUS OF THE EXTENDED PERIOD REMAINS ON A TRANSITION TO MUCH COLDER AIR ACROSS THE REGION AS THE POLAR VORTEX DIVES INTO EASTERN CANADA AND SERVES TO AMPLIFY THE UPPER TROUGH OVER THE EASTERN PART OF THE COUNTRY. DRY WEATHER AND LARGELY SEASONABLE TEMPS WILL CONTINUE THROUGH SATURDAY AS NORTHWEST FLOW ALOFT PERSISTS ACROSS THE OHIO VALLEY. HIGHS IN THE 30S FRIDAY WILL WARM INTO THE 40S SATURDAY AS BRIEF WARM ADVECTION DEVELOPS AHEAD OF A STRONG WAVE MOVING INTO THE GREAT LAKES. MODEL CONSENSUS TRACKS THE SURFACE WAVE TO THE NORTH OF THE REGION SATURDAY NIGHT...WITH THE MAIN IMPACTS TO CENTRAL INDIANA BEING AN INCREASE IN WINDS AND A WINDSHIFT AS THE INITIAL SHOT OF COLDER AIR ADVECTS INTO THE AREA. THIS WILL BE FOLLOWED BY A CLIPPER-LIKE SYSTEM FOR MONDAY...USHERING IN A REINFORCING AND COLDER AIRMASS AS A PIECE OF OF THE POLAR VORTEX DIVES INTO THE GREAT LAKES. WHILE MODELS ARE NOT PICKING UP ON A LOT OF MOISTURE WITH THE CLIPPER...EXPECT SNOW SHOWERS TO ACCOMPANY THE SYSTEM AND HAVE INCLUDED CHANCE POPS SUNDAY NIGHT AND MONDAY. 850MB TEMPS BELOW -20C CONTINUE TO SHOW UP OVER THE FORECAST AREA ON BOTH THE OP GFS AND ECMWF BY MONDAY/TUESDAY. AT THIS POINT HAVE HIGHS FALLING INTO THE LOWER/MID 20S BY MONDAY. NOT OUT OF THE QUESTION THAT IF THESE 850MB TEMPS ARE REALIZED THAT HIGHS COULD CONCEIVABLY BE EVEN COLDER EARLY NEXT WEEK. && .AVIATION /DISCUSSION FOR THE 14/21Z TAF UPDATE/... ISSUED AT 316 PM EST MON JAN 14 2013 LOW CLOUDS HAVE SCATTERED AT ALL SITES BUT LAF...AND HAVE UPDATED TAFS TO REFLECT THIS. PREVIOUS DISCUSSION FOLLOWS. ISSUED AT 1222 PM EST MON JAN 14 2013 MVFR CEILINGS LIKELY TO PERSIST THROUGH THE AFTERNOON...AND POSSIBLY TO SOME DEGREE TONIGHT. THE COMBINATION OF COLD ADVECTION...GOOD LAPSE RATES AND VEERING N/NE FLOW IN THE LOWER LEVELS HAS ENABLED CEILINGS AROUND 1500FT TO REDEVELOP AND EXPAND BACK INTO CENTRAL INDIANA EARLY THIS AFTERNOON. WITH MOISTURE INCREASING A BIT THROUGH THE BOUNDARY LAYER...EXPECT MVFR CEILINGS TO MAINTAIN TO SOME DEGREE FOR THE REST OF THE AFTERNOON. IN ADDITION TO THE STRATOCU...FAIRLY DENSE CANOPY OF MID LEVEL CLOUDS WILL MOVE ACROSS THE OHIO VALLEY IN FAT SOUTHWEST FLOW ALOFT. NORTHERLY WINDS WILL BE LESS THAN 10KTS THROUGH SUNSET. CLOUD FORECAST TONIGHT HAS SOME UNCERTAINTY AS RAP SOUNDINGS INDICATING SHALLOW LAYER OF LOW LEVEL MOISTURE PERSISTING. WHILE FLOW THROUGH 925MB WEAKENS...IT REMAINS FROM THE NORTHEAST INTO THE OVERNIGHT. HAVE INTRODUCED SCATTERED CEILINGS AT 1500FT TONIGHT AND WILL ADJUST AS NECESSARY. MID LEVEL CLOUDS WILL CONTINUE TO MOVE ACROSS THE REGION IN THE SOUTHWEST FLOW AS WELL. SHOULD FINALLY SEE MOSTLY CLEAR SKIES BY TUESDAY MORNING AS CENTER OF HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY WITH DEEPER SUBSIDENCE NOTED IN THE MODEL SOUNDINGS. WINDS WILL VEER TO THE NORTHEAST AND REMAIN AT 10KTS OR LESS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...MK NEAR TERM...MK/CP SHORT TERM...MK LONG TERM....RYAN AVIATION...RYAN/NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
252 PM EST MON JAN 14 2013 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 308 AM EST MON JAN 14 2013 HIGH PRESSURE WILL BUILD FROM THE PLAINS TO THE LOWER GREAT LAKES AND OHIO VALLEY ALLOWING FOR A DRY FORECAST THROUGH SUNDAY. BELOW NORMAL TEMPERATURES TO START THE WEEK WILL BECOME SEASONABLE BY MIDWEEK. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1106 AM EST MON JAN 14 2013 SATELLITE AT 11 AM SHOWS PARTLY CLOUDY SKIES ACROSS MOST OF CENTRAL INDIANA WITH A BIT MORE CLOUD COVERAGE IN THE NORTHEAST. EXPECT PARTLY CLOUDY TO BE THE RULE FOR THE REST OF THE DAY. GOING FORECAST HIGHS IN THE MID 20S TO LOW 30S LOOK RIGHT ON TRACK. PREVIOUS DISCUSSION FOLLOWS... MAIN FOCUS TODAY WILL BE ON CLEARING AS STRATOCU DECK WAS CURRENTLY DROPPING SOUTHEAST ACROSS THE EASTERN HALF OF CENTRAL INDIANA BEHIND A DEPARTING COLD FRONT ACROSS THE APPALACHIANS. MODELS IN GOOD AGREEMENT ON PLAINS HIGH PRESSURE BUILDING IN ACROSS THE FORECAST AREA. MODEL TIME SECTIONS AND SOUNDINGS ARE ALSO SHOWING THINNING OF THE LOW LEVEL MOISTURE ASSOCIATED WITH THE STRATOCU DECK...AND SATELLITE TRENDS SUGGEST THEY WILL DEPART TO THE SOUTHEAST DESPITE WHAT 00Z MOS WAS SUGGESTING. MEANWHILE...UPPER WAVE IN FAST SOUTHWEST FLOW ALOFT COULD BRING SOME INCREASED CLOUD COVER LATE TO THE SOUTHEAST COUNTIES. DRY DAY SHOULD ALLOW AREA CREEKS AND STREAMS TO DROP BELOW FLOOD STAGE AS THEY EMPTY INTO THE MAIN RIVERS WITH MINOR TO MODERATE FLOODING ON MOST FORECAST POINTS. 00Z MOS TEMPERATURES AND ALLBLEND MATCH UP PRETTY WELL AND LOOK REASONABLE CONSIDERING THE NORTHWEST COLD ADVECTION. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 308 AM EST MON JAN 14 2013 MODELS AGREE HIGH PRESSURE AND LIMITED MOISTURE SHOULD ALLOW FOR LITTLE CLOUD COVER THROUGH THE SHORT TERM. SHOULD ONLY SEE SOME INCREASE IN CLOUDS SOUTH LATE TUESDAY AS AN INVERTED TROUGH SLIDES ACROSS THE SOUTHEASTERN STATES AND SOME INCREASE IN CLOUDS NORTH LATE WEDNESDAY AS A COLD FRONT DROPS SOUTH TO THE LOWER GREAT LAKES. LOW LEVEL FLOW IS EXPECTED TO VEER TO THE NORTH TONIGHT...NORTHEAST ON TUESDAY AND SOUTHWEST BY WEDNESDAY. THIS WILL ALLOW TEMPERATURES TO WARM TO THE MID 30S NORTH AND LOWER 40S SOUTH PER SIMILAR 00Z MOS AND ALLBLEND BY WEDNESDAY. THE DRY WEATHER WILL ALLOW MINOR TO MODERATE RIVER FLOODING TO RUN ITS COURSE WITHOUT ANY HITCHES. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... ISSUED AT 252 PM EST MON JAN 14 2013 FOCUS OF THE EXTENDED PERIOD REMAINS ON A TRANSITION TO MUCH COLDER AIR ACROSS THE REGION AS THE POLAR VORTEX DIVES INTO EASTERN CANADA AND SERVES TO AMPLIFY THE UPPER TROUGH OVER THE EASTERN PART OF THE COUNTRY. DRY WEATHER AND LARGELY SEASONABLE TEMPS WILL CONTINUE THROUGH SATURDAY AS NORTHWEST FLOW ALOFT PERSISTS ACROSS THE OHIO VALLEY. HIGHS IN THE 30S FRIDAY WILL WARM INTO THE 40S SATURDAY AS BRIEF WARM ADVECTION DEVELOPS AHEAD OF A STRONG WAVE MOVING INTO THE GREAT LAKES. MODEL CONSENSUS TRACKS THE SURFACE WAVE TO THE NORTH OF THE REGION SATURDAY NIGHT...WITH THE MAIN IMPACTS TO CENTRAL INDIANA BEING AN INCREASE IN WINDS AND A WINDSHIFT AS THE INITIAL SHOT OF COLDER AIR ADVECTS INTO THE AREA. THIS WILL BE FOLLOWED BY A CLIPPER-LIKE SYSTEM FOR MONDAY...USHERING IN A REINFORCING AND COLDER AIRMASS AS A PIECE OF OF THE POLAR VORTEX DIVES INTO THE GREAT LAKES. WHILE MODELS ARE NOT PICKING UP ON A LOT OF MOISTURE WITH THE CLIPPER...EXPECT SNOW SHOWERS TO ACCOMPANY THE SYSTEM AND HAVE INCLUDED CHANCE POPS SUNDAY NIGHT AND MONDAY. 850MB TEMPS BELOW -20C CONTINUE TO SHOW UP OVER THE FORECAST AREA ON BOTH THE OP GFS AND ECMWF BY MONDAY/TUESDAY. AT THIS POINT HAVE HIGHS FALLING INTO THE LOWER/MID 20S BY MONDAY. NOT OUT OF THE QUESTION THAT IF THESE 850MB TEMPS ARE REALIZED THAT HIGHS COULD CONCEIVABLY BE EVEN COLDER EARLY NEXT WEEK. && .AVIATION /DISCUSSION FOR 141800Z TAF ISSUANCE/... ISSUED AT 1222 PM EST MON JAN 14 2013 MVFR CEILINGS LIKELY TO PERSIST THROUGH THE AFTERNOON...AND POSSIBLY TO SOME DEGREE TONIGHT. THE COMBINATION OF COLD ADVECTION...GOOD LAPSE RATES AND VEERING N/NE FLOW IN THE LOWER LEVELS HAS ENABLED CEILINGS AROUND 1500FT TO REDEVELOP AND EXPAND BACK INTO CENTRAL INDIANA EARLY THIS AFTERNOON. WITH MOISTURE INCREASING A BIT THROUGH THE BOUNDARY LAYER...EXPECT MVFR CEILINGS TO MAINTAIN TO SOME DEGREE FOR THE REST OF THE AFTERNOON. IN ADDITION TO THE STRATOCU...FAIRLY DENSE CANOPY OF MID LEVEL CLOUDS WILL MOVE ACROSS THE OHIO VALLEY IN FAT SOUTHWEST FLOW ALOFT. NORTHERLY WINDS WILL BE LESS THAN 10KTS THROUGH SUNSET. CLOUD FORECAST TONIGHT HAS SOME UNCERTAINTY AS RAP SOUNDINGS INDICATING SHALLOW LAYER OF LOW LEVEL MOISTURE PERSISTING. WHILE FLOW THROUGH 925MB WEAKENS...IT REMAINS FROM THE NORTHEAST INTO THE OVERNIGHT. HAVE INTRODUCED SCATTERED CEILINGS AT 1500FT TONIGHT AND WILL ADJUST AS NECESSARY. MID LEVEL CLOUDS WILL CONTINUE TO MOVE ACROSS THE REGION IN THE SOUTHWEST FLOW AS WELL. SHOULD FINALLY SEE MOSTLY CLEAR SKIES BY TUESDAY MORNING AS CENTER OF HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY WITH DEEPER SUBSIDENCE NOTED IN THE MODEL SOUNDINGS. WINDS WILL VEER TO THE NORTHEAST AND REMAIN AT 10KTS OR LESS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...MK NEAR TERM...MK/CP SHORT TERM...MK LONG TERM....RYAN AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1235 PM EST MON JAN 14 2013 .UPDATE... UPDATE SENT EARLIER TO EXPAND IN TIME AND SPACE CLOUD COVER AND REINTRODUCE FLURRIES FOR MUCH OF THE AREA INTO EARLY AFTERNOON. LAKE EFFECT CLOUDS WERE HOLDING STRONG ACROSS MUCH OF THE FORECAST AREA WITH SEVERAL LOCATIONS REPORTING FLURRY ACTIVITY. NO ACCUMS ARE EXPECTED SO KEPT THINGS SIMPLE AND WENT WITH SCT FLURRIES INTO EARLY AFTERNOON WHEN LL FLOW WILL WEAKEN AND DRY AIR BECOME MORE ENTRAINED. NO MODIFICATIONS TO ANY OTHER PARTS OF THE FORECAST WITH TEMPS STILL GENERALLY ON TRACK. && .AVIATION... MVFR CIGS HOLDING AS A RESULT OF LAKE EFFECT CLOUD COVER. CONDITIONS SHOULD IMPROVE BY LATE AFTERNOON AS DRIER AIR WORKS IN. TAFS PATCHED UP TO REFLECT THIS WITH VFR CONDITIONS ANTICIPATED AFTER 00Z AND FOR THE REMAINDER OF THE PERIOD. && .PREV DISCUSSION... /ISSUED 645 AM EST MON JAN 14 2013/ SHORT TERM... /TODAY THROUGH TUESDAY NIGHT/ NMRS MESOGAMMA THERMAL ROLLS CRNTLY BLOSSOMING WSR-88 VCP 31 RETURNS ERLY THIS MORNING...EXTNDG FARTHER SOUTH THAN TYPICAL LAKE RESPONSE...AT LEAST TO KRCR-WABASH LN. LK MSTR ENHANCEMENT RATHER MINIMAL GIVEN ONLY LWR TEENS LK/8H THERMAL DIFFERENTIAL ACRS FAR SRN LK MI. THIN LYR LIFT ON NOSE OF 30-35KT 8H JETLET/SHORTWAVE FM NRN IL AT 03 UTC. 8H PSUEDOFRONT APPEARS ORTHOGONALLY ALONG LEADING EDGE OF RAP ANALYZED THIN LYR NEAR SFC/950-900 MB/ FGEN ZONE LAID OUT SRN LK HUR-SERN FA-SRN IN...WHICH SHOULD QUELL FLURRIES MENTION BY ABOUT 14 UTC. THIS THE ONLY SENSIBLE WX IN THE SHORT TERM PD. THEREAFTER...THE DEEP SCOUR OF MSTR BY CP CANADIAN PLAINS AIRMASS TO CONT TO ERODE RMNG STRATOCU FIELD TDY ON LEADING EDGE OF 1034MB RIDGE. ANTICIPATE POOR THERMAL RECOVERY THOUGH IN LIGHT OF SIG AIRMASS EXCHANGE ALONG WITH POTNL INCRS IN CI/CS LTR THIS AFTN ASSOCD WITH INTENSE ULVL JETSTREAK ON ORDER OF 180-200 KTS LIFTG THROUGH MID MS VLY TO FAR SRN ONT THIS EVE. GOOD POTNL FOR DECOUPLED BLYR LATE TONIGHT. DOWN TO LWR TEENS/PSBLY LWR SINGLE DIGITS...SPCLY FAR WRN CWA WITH BEST DURATION FOR LONGWAVE LOSSES. SLIGHT SFC- 925MB THERMAL MODIFICATION BY DAYBREAK WED...ALONG WITH INCRSD MIXED BL...WITH CWA ON SERN PERIPHERY OF RAMPING FLOW ASSOCD WITH HIGH BELTED CLIPPER. LONG TERM... /WEDNESDAY THROUGH SUNDAY/ A LONGWAVE TROF WILL AMPLIFY OVER EASTERN NORTH AMERICA THIS PERIOD AS A PRECURSOR OF THE ARRIVAL OF VERY COLD AIR LATE IN THE PERIOD. THE 500 MB GFS AND CANADIAN ANALOGS...GFS AND CANADIAN ENSEMBLES AND THE ECMWF ALL SUPPORT THE ESTABLISHMENT OF A MUCH COLDER PATTERN EARLY NEXT WEEK. AHEAD OF THE AMPLIFYING UPPER TROF...A WEAKER TROF WILL MOVE ACROSS THE AREA ACCOMPANIED BY A COLD FRONT WEDNESDAY NIGHT. THERE IS NOT MUCH SUPPORT FOR PRECIPITATION WITH THIS SYSTEM INCLUDING LAKE EFFECT SNOW. MOISTURE IS LIMITED AND FORCING IS WEAK. THE MOST UNSTABLE LAKE EFFECT DELTA T VALUES BEFORE SUNDAY ARE 10 TO 14...BUT WITH AN UNFAVORABLE FETCH OVER MUCH OF THE PERIOD...KEPT THE FORECAST DRY. FOR LATE IN THE PERIOD...GUT FEELING HIGHS SUNDAY ARE TOO WARM. HOWEVER...LEFT HIGHS AROUND 30 MOST AREAS GIVEN THE UNCERTAINTY OF THE ARRIVAL TIME OF THE FRONT. THE GFS MEAN ENSEMBLE MOS HIGHS SUNDAY ARE 22 TO 27 WHICH MAY BE ON TRACK. A PERIOD OF LIGHT SNOW IN THE ARCTIC AIR MAY ALSO EVENTUALLY NEED TO BE ADDED TO THE FORECAST SUNDAY IF A FASTER FRONTAL PASSAGE PREVAILS. TEMPERATURES MAY BE STEADY OR SLOWING FALLING SUNDAY. FOR NOW...WENT WITH A SMALL DIURNAL RISE SUNDAY. MARINE... LOOK FOR RAPIDLY INCRSG GRADIENT FLOW AS ULVL TROF SHIFTS GRDLY EWD INTO WRN GRTLKS BY LATE TUE. MIDWEEK MARINE HEADLINES TO LATER FOCUS ON NEED FOR NEARSHORE GALE WATCH/WARNING WITH BEST WINDOW IN THE 12-21 UTC WED TIMEFRAME. ACCELERATION RATE OF FLOW SHOULD PRECLUDE LEAD IN SC.Y...THOUGH LATER FCSTS TO FINE TUNE AS NEED BE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...MURPHY LONG TERM...SKIPPER AVIATION...FISHER UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1222 PM EST MON JAN 14 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 308 AM EST MON JAN 14 2013 HIGH PRESSURE WILL BUILD FROM THE PLAINS TO THE LOWER GREAT LAKES AND OHIO VALLEY ALLOWING FOR A DRY FORECAST THROUGH SUNDAY. BELOW NORMAL TEMPERATURES TO START THE WEEK WILL BECOME SEASONABLE BY MIDWEEK. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1106 AM EST MON JAN 14 2013 SATELLITE AT 11 AM SHOWS PARTLY CLOUDY SKIES ACROSS MOST OF CENTRAL INDIANA WITH A BIT MORE CLOUD COVERAGE IN THE NORTHEAST. EXPECT PARTLY CLOUDY TO BE THE RULE FOR THE REST OF THE DAY. GOING FORECAST HIGHS IN THE MID 20S TO LOW 30S LOOK RIGHT ON TRACK. PREVIOUS DISCUSSION FOLLOWS... MAIN FOCUS TODAY WILL BE ON CLEARING AS STRATOCU DECK WAS CURRENTLY DROPPING SOUTHEAST ACROSS THE EASTERN HALF OF CENTRAL INDIANA BEHIND A DEPARTING COLD FRONT ACROSS THE APPALACHIANS. MODELS IN GOOD AGREEMENT ON PLAINS HIGH PRESSURE BUILDING IN ACROSS THE FORECAST AREA. MODEL TIME SECTIONS AND SOUNDINGS ARE ALSO SHOWING THINNING OF THE LOW LEVEL MOISTURE ASSOCIATED WITH THE STRATOCU DECK...AND SATELLITE TRENDS SUGGEST THEY WILL DEPART TO THE SOUTHEAST DESPITE WHAT 00Z MOS WAS SUGGESTING. MEANWHILE...UPPER WAVE IN FAST SOUTHWEST FLOW ALOFT COULD BRING SOME INCREASED CLOUD COVER LATE TO THE SOUTHEAST COUNTIES. DRY DAY SHOULD ALLOW AREA CREEKS AND STREAMS TO DROP BELOW FLOOD STAGE AS THEY EMPTY INTO THE MAIN RIVERS WITH MINOR TO MODERATE FLOODING ON MOST FORECAST POINTS. 00Z MOS TEMPERATURES AND ALLBLEND MATCH UP PRETTY WELL AND LOOK REASONABLE CONSIDERING THE NORTHWEST COLD ADVECTION. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... ISSUED AT 308 AM EST MON JAN 14 2013 MODELS AGREE HIGH PRESSURE AND LIMITED MOISTURE SHOULD ALLOW FOR LITTLE CLOUD COVER THROUGH THE SHORT TERM. SHOULD ONLY SEE SOME INCREASE IN CLOUDS SOUTH LATE TUESDAY AS AN INVERTED TROUGH SLIDES ACROSS THE SOUTHEASTERN STATES AND SOME INCREASE IN CLOUDS NORTH LATE WEDNESDAY AS A COLD FRONT DROPS SOUTH TO THE LOWER GREAT LAKES. LOW LEVEL FLOW IS EXPECTED TO VEER TO THE NORTH TONIGHT...NORTHEAST ON TUESDAY AND SOUTHWEST BY WEDNESDAY. THIS WILL ALLOW TEMPERATURES TO WARM TO THE MID 30S NORTH AND LOWER 40S SOUTH PER SIMILAR 00Z MOS AND ALLBLEND BY WEDNESDAY. THE DRY WEATHER WILL ALLOW MINOR TO MODERATE RIVER FLOODING TO RUN ITS COURSE WITHOUT ANY HITCHES. && .LONG TERM /THURSDAY THROUGH MONDAY/... ISSUED AT 331 AM EST MON JAN 14 2013 A COOL DRY WEATHER PATTERN WILL REMAIN IN PLACE FOR MOST OF THE LONG TERM PERIOD. A DISTURBANCE WILL PASS ACROSS THE GREAT LAKES REGION ON SATURDAY...BUT WILL NOT IMPACT CENTRAL INDIANA. THE MAIN FOCUS OF THE EXTENDED PERIOD IS AT THE TAIL END WHEN A BROAD UPPER LEVEL TROUGH WILL BRING THE NEXT CHANCE FOR SOME SNOW TO CENTRAL INDIANA. THE EURO IS THE MOST AGGRESSIVE WITH THE LOW...HINTING AT SOME ACCUMULATING SNOWFALL...AND THE LATEST INITIALIZATION IS FAVORING THE EURO OVER THE GFS. WILL NOT DEVIATE THIS FAR OUT. BEYOND THAT...MODELS ARE HINTING AT A VERY FRIGID AIRMASS BY THE MIDDLE OF NEXT WEEK. && .AVIATION /DISCUSSION FOR 141800Z TAF ISSUANCE/... ISSUED AT 1222 PM EST MON JAN 14 2013 MVFR CEILINGS LIKELY TO PERSIST THROUGH THE AFTERNOON...AND POSSIBLY TO SOME DEGREE TONIGHT. THE COMBINATION OF COLD ADVECTION...GOOD LAPSE RATES AND VEERING N/NE FLOW IN THE LOWER LEVELS HAS ENABLED CEILINGS AROUND 1500FT TO REDEVELOP AND EXPAND BACK INTO CENTRAL INDIANA EARLY THIS AFTERNOON. WITH MOISTURE INCREASING A BIT THROUGH THE BOUNDARY LAYER...EXPECT MVFR CEILINGS TO MAINTAIN TO SOME DEGREE FOR THE REST OF THE AFTERNOON. IN ADDITION TO THE STRATOCU...FAIRLY DENSE CANOPY OF MID LEVEL CLOUDS WILL MOVE ACROSS THE OHIO VALLEY IN FAT SOUTHWEST FLOW ALOFT. NORTHERLY WINDS WILL BE LESS THAN 10KTS THROUGH SUNSET. CLOUD FORECAST TONIGHT HAS SOME UNCERTAINTY AS RAP SOUNDINGS INDICATING SHALLOW LAYER OF LOW LEVEL MOISTURE PERSISTING. WHILE FLOW THROUGH 925MB WEAKENS...IT REMAINS FROM THE NORTHEAST INTO THE OVERNIGHT. HAVE INTRODUCED SCATTERED CEILINGS AT 1500FT TONIGHT AND WILL ADJUST AS NECESSARY. MID LEVEL CLOUDS WILL CONTINUE TO MOVE ACROSS THE REGION IN THE SOUTHWEST FLOW AS WELL. SHOULD FINALLY SEE MOSTLY CLEAR SKIES BY TUESDAY MORNING AS CENTER OF HIGH PRESSURE BUILDS ACROSS THE OHIO VALLEY WITH DEEPER SUBSIDENCE NOTED IN THE MODEL SOUNDINGS. WINDS WILL VEER TO THE NORTHEAST AND REMAIN AT 10KTS OR LESS. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...MK NEAR TERM...MK/CP SHORT TERM...MK LONG TERM....TDUD AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS GOODLAND KS
233 PM MST MON JAN 14 2013 .SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY) ISSUED AT 111 PM MST MON JAN 14 2013 CURRENT WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE TROUGH EXTENDING FROM CANADA ACROSS THE PLAINS AND SW US TO THE BAJA PENINSULA. MEAN AXIS IS CURRENTLY UPSTREAM OF CWA ALONG THE CENTRAL ROCKIES WITH SURFACE TROUGH ALONG FRONT RANGE. RUC INDICATES AXIS OF H85-H7 FRONTOGENESIS IN PLACE ACROSS EASTERN COLORADO AND FAR WESTERN KANSAS WHERE LIGHT SNOW HAS BEEN FALLING FOR MOST OF THE DAY. AS THE UPPER LEVEL TROUGH SHIFTS EAST THIS EVENING THIS AXIS OF FORCING WILL BEGIN TO WEAKEN AND SHIFT SOUTH...WITH SNOW COMING TO AN END OVER OUR SW CWA BY 03Z. I COULD NOT RULE OUT ADDITIONAL SNOW ACCUMULATION AROUND ONE INCH ALONG AN AXIS FROM STRATTON COLORADO TO BENKELMAN NEBRASKA THROUGH THIS AFTERNOON WHERE RADAR SHOWS SOME INTENSIFICATION...HOWEVER MOST LOCATIONS SHOULD SEE LESS THAN ONE HALF INCH TOTAL SNOW ACCUMULATION FOR THIS EVENT. SUBSIDENCE AND A DRY AIR MASS WILL BEGIN TO WORK IN OVER THE CWA AFTER MIDNIGHT WITH CLEARING SKIES FROM THE NORTHWEST OVERNIGHT. THERE WILL BE LITTLE CHANGE IN THE COLD AIRMASS FROM LAST NIGHT...SO DEPENDING ON HOW QUICKLY CLOUDS CLEAR WE COULD SEE NEGATIVE TEMPERATURES ONCE AGAIN OVER PARTS OF THE CWA. FOR NOW I LIMITED COLDEST TEMPS TO THE NORTH AND WEST WHERE CLOUDS ARE MOST LIKELY TO CLEAR BEFORE SUNRISE. AIRMASS WILL BEGIN TO MODERATE BY MIDDAY TUESDAY AS LEE TROUGH DEVELOPS AND WINDS SHIFT TO THE WEST. IT IS A TOUGH CALL ON WHAT IMPACT LINGERING SNOW PACK WILL HAVE...HOWEVER WE SHOULD SEE TEMPERATURES IN THE LOW TO MID 30S ACROSS ALL THE CWA...WITH A FEW LOCATIONS IN THE SOUTH AND EAST POSSIBLY WARMER. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 233 PM MST MON JAN 14 2013 FORECAST PROBLEMS WILL BE AMOUNT OF WARMUP DURING THE EARLY PORTION OF THIS PERIOD FOLLOWED BY HOW MUCH TO COOL IT DOWN AT THE END OF THE PERIOD. SATELLITE SHOWING AN AMPLIFIED FLOW STARTING WITH A BROAD...DEEP AND COMPLICATED UPPER TROUGH OVER THE WESTERN HALF OF THE PACIFIC WHICH IS MAINTAINING/AMPLIFYING AN UPPER RIDGE NEAR THE WEST COAST OF NORTH AMERICA. THIS TRANSITIONS TO A TROUGH OVER THE CENTER OF THE COUNTRY WHICH HAS/CONTINUES TO SPLIT. COLD AIR REMAINS OVER THE AREA AND UPSTREAM AT THIS TIME. MODELS INITIALIZED FINE AT JET LEVEL. HOWEVER...THEY WERE A LITTLE UNDERDONE ON THE SPEEDS BEHIND THE UPPER TROUGH OVER THE COUNTRY. THE GFS WAS DOING A LITTLE BETTER THAN THE CANADIAN AND NAM. MODELS INITIALIZED FINE AT MID LEVELS WITH THE ECMWF AND UKMET DOING A LITTLE BETTER THAN THE GFS AND CANADIAN. THE ECMWF WAS DOING THE BEST AT THE SURFACE. THE ECMWF WAS DOING A LITTLE BETTER THAN THE GFS...UKMET AND CANADIAN ON THE LOW LEVEL THERMAL FIELD. TUESDAY NIGHT/WEDNESDAY...LEFT FRONT QUADRANT OF THE JET MOVES ACROSS DURING THE NIGHT. UPPER TROUGH WILL HAVE MOVED EAST OF THE AREA BY THE BEGINNING OF THIS PERIOD. IN ADDITION TO THE LIFT FROM THE JET...MOISTURE INCREASES THROUGH MID LEVELS ON THE WEST SIDE OF THE TROUGH. THERE IS SOME MODERATE FRONTOGENESIS AS WELL. LAPSE RATES ARE NOT THAT GREAT. HOWEVER WITH THE COLD AIR IN PLACE AND THE MODELS SHOWING DEEP ENOUGH MOISTURE...WILL INSERT FLURRIES INTO THE NORTHWEST HALF SINCE THE SYNOPTIC LIFT IS NOT THAT GREAT BUT MESOSCALE FORCING IS PRETTY GOOD. WHATEVER FALLS SHOULD BE DONE BY 06Z. AFTER THE FLURRIES END...SUBSIDENCE INCREASE BEHIND JET AND UPPER TROUGH. SO WINDS COULD BECOME BREEZY FROM A DOWNSLOPE DIRECTION FOR A SHORT PERIOD OF TIME. THIS SHOULD MAKE THE MINS WARMER AND DID WARM THEM SOME BUT MAYBE NOT ENOUGH. PLENTY OF SUN AND DOWNSLOPE WINDS SHOULD MAKE FOR A MUCH WARMER DAY THAN WE HAVE BEEN HAVING LATELY. IN GENERAL...MAXES SHOULD RANGE FROM THE MIDDLE 40S TO NEAR 50 DEGREES. WEDNESDAY NIGHT/THURSDAY...DOWNSLOPE WINDS SHOULD KEEP MINS WARMER AGAIN. WILL HAVE PLENTY OF SUN BUT NOT AS FAVORABLE OF A WIND FIELD. NEW GUIDANCE INDICATES HIGH TEMPERATURES SIMILAR TO WEDNESDAYS AND DID NOT CHANGE MUCH. THURSDAY NIGHT THROUGH MONDAY...CURRENT AMPLIFIED PATTERN FLATTENS OUT A LITTLE BIT EARLY IN THE PERIOD BEFORE BECOMING VERY AMPLIFIED BY THE END OF THE PERIOD ONCE AGAIN. THROUGH FRIDAY SHOULD MAINTAIN HIGH TEMPERATURES VERY SIMILAR TO WHAT THEY WERE ON WEDNESDAY AND THURSDAY. THEN A BIG CHANGE IS GOING TO OCCUR IN TEMPERATURE BUT WITH UNCERTAINTY IN TIMING AND MAGNITUDE OF THIS TEMPERATURE. GIVEN WHAT THE PATTERN IS...HAVING A MUCH COLDER AIR MASS INTRUDE INTO THE REGION IS PRETTY MUCH A GIVEN BUT THE MODELS DISAGREE ON HOW FAST THEY WHAT TO DO IT. THE GFS AND CANADIAN BRING IN THE COOLER AIR FASTER WHICH IS FROM LATE SATURDAY AFTERNOON INTO THE NIGHT. THE 00Z AND 12Z ECMWF PRETTY MUCH KEEP THE COLDER AIR OUT DURING THE DAY ON SATURDAY. HOWEVER...THE 12Z ECMWF IS MUCH QUICKER THAN THE OLD RUN IN BRINGING THE COLDER AIR ON SATURDAY NIGHT AND SUNDAY WHICH A BIG DIFFERENCE ON SUNDAY MAXES. MODELS IN BETTER AGREEMENT AND MUCH BETTER THAN EARLIER IN BRINGING IN AN ABSOLUTELY FRIGID AIR MASS SUNDAY NIGHT INTO MONDAY. THROUGH SATURDAY NIGHT LEFT IN WHAT THE CRH_INIT GAVE ME ALTHOUGH IT IS POSSIBLE THAT SATURDAY AND SATURDAY NIGHT TEMPERATURES COULD BE COLDER. FELT PER THE AMPLIFIED PATTERN MAKING THE AREA SUSCEPTIBLE TO HAVING MUCH COLDER AIR BROUGHT IN...SIGNIFICANT SNOW FIELD OVER THE NORTH CENTRAL PORTION OF THE COUNTRY...AND MORE MODEL SUPPORT FOR A SOONER ARRIVING COLD AIR MASS WHICH IS NOT UNCOMMON WITH THIS MAGNITUDE OF COLD AIR...ADJUSTED THE TEMPERATURES...ESPECIALLY THE MAXES FOR SUNDAY AND MONDAY...DOWN FROM THE INIT. CONSIDERING THE AIR MASS WE HAVE HAD IN PLACE FOR THE LAST FEW DAYS AND WHAT THE MODELS ARE SHOWING...THESE TEMPERATURES WILL PROBABLY NOT BE COLD ENOUGH...BUT STARTED THE TREND DOWN. IN REGARDS TO THE PRECIPITATION...LEFT WHAT THE CRH_INIT GAVE ME WHICH HAS IT DRY DURING THE ENTIRE PERIOD. ALTHOUGH WOULD NOT BE SURPRISED TO SEE SOME FLURRIES WHEN THE COLD AIR MASS BEGINS TO ENTER THE AREA. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1028 AM MST MON JAN 14 2013 MAIN AVIATION CONCERN WILL CONTINUE TO BE LIGHT SNOW DURING THE DAY TODAY AT BOTH KGLD AND KMCK. VFR CONDITIONS SHOULD PERSIST...THOUGH EITHER TERMINAL MAY BRIEFLY DROP TO MVFR/IFR BEFORE SNOW TAPERS OF THIS AFTERNOON/EVENING. CONFIDENCE WAS TOO LOW...AND DUE TO THE INFREQUENCY OF THESE CONDITIONS AT KGLD SO FAR THIS MORNING I DECIDED AGAINST A TEMPO GROUP DURING THIS UPDATE. ANY LINGERING SNOW SHOULD END AT KMCK AROUND 00Z...AND BY 03Z AT KGLD. WINDS WOULD REMAIN AT OR BELOW 10KT THROUGH THE PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...BULLER AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
112 PM MST MON JAN 14 2013 .SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY) ISSUED AT 111 PM MST MON JAN 14 2013 CURRENT WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE TROUGH EXTENDING FROM CANADA ACROSS THE PLAINS AND SW US TO THE BAJA PENINSULA. MEAN AXIS IS CURRENTLY UPSTREAM OF CWA ALONG THE CENTRAL ROCKIES WITH SURFACE TROUGH ALONG FRONT RANGE. RUC INDICATES AXIS OF H85-H7 FRONTOGENESIS IN PLACE ACROSS EASTERN COLORADO AND FAR WESTERN KANSAS WHERE LIGHT SNOW HAS BEEN FALLING FOR MOST OF THE DAY. AS THE UPPER LEVEL TROUGH SHIFTS EAST THIS EVENING THIS AXIS OF FORCING WILL BEGIN TO WEAKEN AND SHIFT SOUTH...WITH SNOW COMING TO AN END OVER OUR SW CWA BY 03Z. I COULDNT RULE OUT ADDITIONAL SNOW ACCUMULATION AROUND ONE INCH ALONG AN AXIS FROM STRATTON COLORADO TO BENKELMAN NEBRASKA THROUGH THIS AFTERNOON WHERE RADAR SHOWS SOME INTENSIFICATION...HOWEVER MOST LOCATIONS SHOULD SEE LESS THAN ONE HALF INCH TOTAL SNOW ACCUMULATION FOR THIS EVENT. SUBSIDENCE AND A DRY AIR MASS WILL BEGIN TO WORK IN OVER THE CWA AFTER MIDNIGHT WITH CLEARING SKIES FROM THE NORTHWEST OVERNIGHT. THERE WILL BE LITTLE CHANGE IN THE COLD AIRMASS FROM LAST NIGHT...SO DEPENDING ON HOW QUICKLY CLOUDS CLEAR WE COULD SEE NEGATIVE TEMPERATURES ONCE AGAIN OVER PARTS OF THE CWA. FOR NOW I LIMITED COLDEST TEMPS TO THE NORTH AND WEST WHERE CLOUDS ARE MOST LIKELY TO CLEAR BEFORE SUNRISE. AIRMASS WILL BEGIN TO MODERATE BY MIDDAY TUESDAY AS LEE TROUGH DEVELOPS AND WINDS SHIFT TO THE WEST. IT IS A TOUGH CALL ON WHAT IMPACT LINGERING SNOW PACK WILL HAVE...HOWEVER WE SHOULD SEE TEMPERATURES IN THE LOW TO MID 30S ACROSS ALL THE CWA...WITH A FEW LOCATIONS IN THE SOUTH AND EAST POSSIBLY WARMER. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 109 AM MST MON JAN 14 2013 THE PERSISTENT UPPER RIDGE REMAINS OVER THE EASTERN PACIFIC AND WEST COAST OF THE UNITED STATES THROUGH THE LONG TERM PORTION OF THE FORECAST. AS A RESULT THE UPPER FLOW OVER THE CENTRAL HIGH PLAINS REGION REMAINS GENERALLY OUT OF THE NORTHWEST WITH THE STRONGER NORTHERN BRANCH OF THE UPPER FLOW REMAINING OVER THE NORTHERN PLAINS THROUGH THE LATTER PORTION OF THE WORK WEEK. THIS WILL KEEP THE CENTRAL HIGH PLAINS REGION GENERALLY DRY AND WARMER THAN NORMAL FOR THIS TIME OF YEAR AS ANY OF THE MAJOR DISTURBANCES MOVING THROUGH THE UPPER FLOW WILL TRACK WELL TO THE NORTH OF THE FORECAST AREA. THROUGH THE WEEKEND AND INTO THE BEGINNING OF NEXT WEEK...THE RIDGE SHARPENS OVER THE WEST COAST AND THE UPPER PATTERN BECOMES MORE AMPLIFIED WITH THE UPPER FLOW TURNING MORE NORTHERLY OVER THE ROCKIES AND HIGH PLAINS. THIS WILL ALLOW COLDER AIR TO DIVE DEEPER TO THE SOUTH THROUGH THE PLAINS STATES WITH TEMPERATURES ACROSS THE FORECAST AREA RETURNING TO NEAR NORMAL ON SUNDAY AND BECOMING SLIGHTLY COOLER THAN NORMAL BY MONDAY. THERE IS A LITTLE PRECIPITATION HINTED AT BY THE GFS ON SUNDAY NIGHT AND MONDAY AS THE COLDER AIRMASS MOVES IN...BUT HAVE KEPT THE FORECAST DRY FOR NOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1028 AM MST MON JAN 14 2013 MAIN AVIATION CONCERN WILL CONTINUE TO BE LIGHT SNOW DURING THE DAY TODAY AT BOTH KGLD AND KMCK. VFR CONDITIONS SHOULD PERSIST...THOUGH EITHER TERMINAL MAY BRIEFLY DROP TO MVFR/IFR BEFORE SNOW TAPERS OF THIS AFTERNOON/EVENING. CONFIDENCE WAS TOO LOW...AND DUE TO THE INFREQUENCY OF THESE CONDITIONS AT KGLD SO FAR THIS MORNING I DECIDED AGAINST A TEMPO GROUP DURING THIS UPDATE. ANY LINGERING SNOW SHOULD END AT KMCK AROUND 00Z...AND BY 03Z AT KGLD. WINDS WOULD REMAIN AT OR BELOW 10KT THROUGH THE PERIOD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...LOCKHART AVIATION...DR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1223 PM EST MON JAN 14 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 535 AM EST MON JAN 14 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH EXTENDING FROM HUDSON BAY THROUGH THE NRN PLAINS INTO THE SW CONUS. THE SHORTWAVE TROUGH THAT BROUGHT -SN/FLURRIES TO UPPER MI AND HELPED ENHANCED THE LES INTO THE WEST HAD LIFTED OFF TO THE NORTHEAST TOWARD QUEBEC. IN ITS WAKE...SHRTWV RIDGING WITH QVECTOR DIV AND SUBSIDENCE HAS HELPED LIMIT LES INTENSITY OVERNIGHT. UPSTREAM...ONLY A WEAK SHRTWV WAS NOTED OVER NEBRASKA. AT THE SFC...A RIDGE EXTENDED FROM SASK THROUGH THE NRN PLAINS INTO THE MID MS VALLEY RESULTING IN W TO WNW FLOW THROUGH THE NRN GREAT LAKES. THE LINGERING LAKE INDUCED TROUGH HAS KEPT THE FOCUS OF LES OVER THE KEWEENAW AND FOR LOCATIONS EAST OF P53. INSTABILITY FOR LES WILL REMAIN FAVORABLE WITH 850 MB TEMPS NEAR -19C PRODUCING LAKE INDUCED CAPES IN THE 400-500 J/KG RANGE. THE DGZ WILL ALSO REMAIN IN THE CONVECTIVE LAYER...LEADING TO HIGH SNOW/WATER RATIOS IN THE 25/1 TO 30/1 RANGE. UPSTREAM LOW LEVEL MOISTURE OVER NRN MN WILL HELP MAINTAIN LES ACROSS WRN LAKE SUPERIOR. MODELS WERE CONSISTENT IN SUGGESTING THAT LOW LEVEL WINDS WILL SLOWLY BACK. AS A RESULT...THE LES INTO THE ERN CWA COULD PRODUCE AN ADDITIONAL 1 TO 3 INCHES BEFORE THE BANDS GRADUALLY SHIFT TOWARD THE SHORELINE AND MOVE OUT OF THE AREA THIS AFTERNOON. OVER THE WEST... THE HIGHER RES MODELS SUGGEST THAT THE STRONGEST LES BAND(S) MAINLY NEAR THE SHORELINE OF ONTONAGON COUNTY TOWARD TWIN LAKES THIS MORNING WOULD GRADUALLY SHIFT THROUGH NRN HOUGHTON COUNTY TODAY AND EVENTUALLY TO CMX-P59 TONIGHT. THERE IS LOWER CONFIDENCE WITH THE SNOWFALL RATES AND AMOUNT OF TIME IT WILL LINGER OVER ANY GIVEN AREA. THE POTENTIAL REMAINS FOR LOCAL AMOUNTS IN THE 4 TO 8 INCH RANGE BOTH TODAY AND TONIGHT AS IT LIFTS THROUGH THESE AREAS. SO...THE LES WARNING WILL CONTINUE AT LEAST UNTIL 12Z/TUE. OVER THE REST OF THE CWA...EXPECT MAINLY JUST A FEW FLURRIES OVER THE NORTH OUTSIDE OF THE MAIN LES AREA. EVEN WITH MORE SUNSHINE TODAY OVER THE SOUTH...TEMPERATURES WILL REMAIN AT OR BELOW NORMAL FROM 12 TO 17 WEST AND IN THE LOWER 20S EAST. THERE MAY ALSO BE ENOUGH CLEARING TONIGHT INLAND WITH LIGHT WSW WINDS AS THE RIDGE BUILDS TOWARD THE REGION TO ALLOW TEMPS TO DIP TO AROUND ZERO. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 535 AM EST MON JAN 14 2013 TUESDAY LOOKS TO BE ONE OF THE FEW BREAKS FROM SNOW FOR MUCH OF THE LAND CWA...AS WINDS BACK TO THE WEST-SOUTHWEST AHEAD OF AN APPROACHING SHORTWAVE AND ASSOCIATED COLD FRONT. THIS WILL PUSH WHAT IS LEFT OF THE BANDS CURRENTLY OVER NORTHERN HOUGHTON AND KEWEENAW COUNTIES ALONG THE WESTERN SHORELINE DURING THE MORNING AND THEN OFFSHORE DURING THE AFTERNOON. THE BANDS WILL ALSO BE DIMINISHING IN INTENSITY DUE TO INCREASING H850 TEMPS. ELSEWHERE...LOOKS TO BE A FAIRLY NICE DAY WITH ONLY A FEW MID LEVEL CLOUDS MOVING THROUGH. HEADING INTO TUESDAY NIGHT...LOOKS LIKE IT COULD BE GUSTY ACROSS MUCH OF UPPER MICHIGAN AHEAD OF THE COLD FRONT. GALES OVER LAKE SUPERIOR STILL LOOK LIKELY...SO WILL CONTINUE GALE WATCH. OVER LAND...INVERSION WILL KEEP MUCH OF THE STRONG 50-60KT LOW LEVEL JET ALOFT. BUT LATE IN THE NIGHT...THINK IT WILL GET A LITTLE GUSTY AS THE 10-14MB 6HR PRESSURE FALLS MOVE ACROSS THE CWA. STRONGEST WINDS WILL LIKELY END UP IN THE SOUTHWEST WIND DOWNSLOPE AREAS NEAR LAKE SUPERIOR...MAYBE APPROACHING 35-45MPH...WHILE THE REST OF THE AREA WILL SEE A FEW HOUR PERIOD OF 25-35MPH GUSTS. THERE IS MUCH BETTER AGREEMENT WITH THE SHORTWAVE AND ASSOCIATED COLD FRONT THAT MOVES THROUGH LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. DUE TO THIS...HAVE DELAYED THE START OF THE SNOW INTO THE OVERNIGHT HOURS. BEST H500 HEIGHT FALLS STAY OVER NORTHERN LAKE SUPERIOR AND SOUTHERN ONTARIO...BUT DECENT H850-500 Q-VECTOR CONVERGENCE MOVES OVER THE NORTHERN HALF OF THE CWA. WILL CONTINUE TO HIGHLIGHT THE HIGHEST POPS OVER THE NORTH HALF OF THE CWA...WITH CHANCES ELSEWHERE. WITH IT MOVING THROUGH FAIRLY QUICKLY...DON/T THINK THERE WILL BE TOO MUCH SNOW ACCUMULATION...WITH THE HIGHEST AMOUNTS OVER THE KEWEENAW AND LUCE COUNTY WHERE THERE COULD BE SOME ENHANCEMENT OFF LAKE MICHIGAN. THE LEAST AMOUNTS WILL LIKELY BE OVER THE CENTRAL CWA...WHERE DRY LOW LEVEL AIR WILL LEAD TO SOME INITIAL EVAPORATION OF THE SNOW. THERE IS A SLIGHT DELAY IN THE COLD AIR SURGING IN BEHIND THE FRONT...SO AFTER SNOW DIMINISHES ON WEDNESDAY MORNING AND EARLY AFTERNOON...PROBABLY WONT BE MUCH GOING ON LAKE EFFECT WISE UNTIL THE COLDER ARRIVES LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. BEHIND THE FRONT...PERSISTENT LAKE EFFECT SNOW IS EXPECTED WEDNESDAY NIGHT THROUGH THURSDAY NIGHT FOR WEST TO NORTHWEST FLOW FAVORED LOCATIONS. THE AREA WILL BE BETWEEN THE SURFACE LOW ROTATING OVER HUDSON BAY AND A HIGH PRESSURE IN THE PLAINS STATES. H850 TEMPS FALLING TO AROUND -24C BEHIND THE FRONT SHOULD PRODUCE SIGNIFICANT LAKE INSTABILITY DUE TO LAKE SUPERIOR WATER TEMPS AROUND 3C. SINCE MODELS ARE SHOWING THE INVERSION AROUND 5KFT TO BE FAIRLY WEAK...LAKE INDUCED EQL LEVELS RISE TO 9-10KFT AND CAPE VALUES APPROACH 900 J/KG. THESE ARE FAIRLY IMPRESSIVE VALUES...BUT THE CONCERN WITH SIGNIFICANT SNOWFALL COMES WITH THE BEST MOISTURE FOCUSED IN THE 2-5KFT RANGE. WITH THE COLD AIR...THE CONVECTIVE PORTION OF THE LAKE EFFECT SHOULD BE ABOVE THE DGZ AND LEAD TO MORE COLUMN/PLATE SNOW TYPE...AT LEAST FOR WEDNESDAY NIGHT AND THURSDAY. THIS WILL LEAD TO LOWER SNOW RATIOS THAN WHAT HAVE BEEN SEEN OVER THE LAST DAY AND GENERALLY IN THE 15-20 TO 1 RANGE. THE PERSISTENT NATURE OF THE SNOW DURING THIS PERIOD WILL LIKELY PRODUCE DECENT LAKE EFFECT SNOW ACCUMULATIONS IN THE FAVORED LOCATIONS AND WILL CONTINUE TO MENTION PERIODS OF MODERATE SNOW IN THE HWO. SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS PERIOD OF LES...WILL MAKE THE JUMP UP TO DEFINITE POPS IN THE WNW TO NW FAVORED AREAS. TIMING OF SHORTWAVES AND ASSOCIATED POCKETS OF DEEPER MOISTURE ARE DIFFICULT TO LOCATE/TIME IN NORTHWEST FLOW...BUT THEY COULD LEAD TO PERIODS OF HEAVY SNOW. THIS WOULD ESPECIALLY BE TRUE ON THURSDAY AFTERNOON/NIGHT WHEN TEMPS WARM SLIGHTLY TO RAISE THE DGZ FROM THE SURFACE. 00Z GFS/ECMWF HAVE GOOD CONSISTENCY WITH SHORTWAVE AND CLIPPER SYSTEM AFFECTING THE AREA ON FRIDAY. CONFIDENCE IN TIMING/LOCATION STILL IS LOW...BUT THE LATEST TRENDS SUGGEST A BETTER H850 WAA FOCUS ACROSS THE CWA FOR FRIDAY. THIS WOULD LEAD TO BETTER SNOWFALL CHANCES /1-2IN OF ACCUM OVER MUCH OF THE CWA/ THAN THE LOW END CHANCES THAT ARE CURRENTLY IN PLACE. IF MODELS CONTINUE TO SHOW THIS IDEA...WILL NEED TO BUMP UP POPS. NORTHWEST FLOW ALOFT WILL CONTINUE INTO THE WEEKEND AS A UPPER RIDGE BUILDS OVER THE PACIFIC NORTHWEST. BUT MODELS ARE REALLY STARTING TO DIFFER IN THE UPPER LOW SPINNING EAST OF HUDSON BAY AND WHAT HAPPENS TO IT THROUGH THE WEEKEND. NO MATTER THE SOLUTION...IT APPEARS THE AREA WILL STILL BE UNDER THE INFLUENCE OF THE UPPER TROUGH BUT THERE APPEARS TO BE STRONGER SHORTWAVES DISRUPTING THE TROUGH SOME. THESE DISRUPTIONS PRODUCES MORE UNCERTAINTY IN THE LOW TRACK FORECAST...WHICH MAKES THE LOW LEVEL WIND FIELDS HIGHLY VARIABLE FOR PINNING DOWN LAKE EFFECT AREAS IN ADDITION TO SYNOPTIC SNOW. WILL FOLLOW A GENERAL MODEL CONSENSUS...WHICH WILL CONTINUE TO FOCUS THE HIGHEST CHANCE POPS NEAR LAKE SUPERIOR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1223 PM EST MON JAN 14 2013 CMX...EXPECT PREDOMINANT MVFR CONDITIONS THRU THIS EVENING IN THE LAKE EFFECT SNOW SHOWERS AND OBS WILL CONTINUE TO BE HIGHLY VARIABLE AS BANDS MOVE THROUGH. AS THE FLOW BACKS MORE TO THE WSW...THE HEAVIER SHSN SHOULD SHIFT TO THE N OF THE SITE LATE TONIGHT. IWD/SAW...SLOWLY BACKING LLVL FLOW TO THE WSW WL ADVECT DRIER AIR OVHD AND ALLOW FOR VFR WX THROUGH THE PERIOD. WILL BE A TEMPORARY MVFR DECK AT IWD WITH LOW LEVEL MOISTURE THIS AFTERNOON MOVING THROUGH. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 535 AM EST MON JAN 14 2013 NORTHWEST WINDS WILL GRADUALLY BACK TODAY AND TONIGHT...WITH MOST LOCATIONS SEEING WINDS IN THE 15-25KT RANGE. AS A COLD FRONT APPROACHES THE AREA ON TUESDAY AND TUESDAY EVENING...SOUTHWEST WINDS WILL INCREASE TO GALES OF 35-45KTS FOR TUESDAY NIGHT. THEN AS THE FRONT MOVES THROUGH ON WEDNESDAY MORNING...THE WINDS ARE EXPECTED TO VEER TO THE NORTHWEST AND STILL PRODUCE GALES TO 40KTS. THE TIMING OF THE GALE WATCH LOOKS TO BE IN GOOD SHAPE AND WILL KEEP IT IN PLACE. NORTHWEST FLOW WILL REMAIN WEDNESDAY NIGHT INTO THURSDAY NIGHT...WITH WINDS GENERALLY IN THE 15-30KT RANGE WITH A FEW GUSTS TO 35KTS ON THURSDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ006-007. LAKE SUPERIOR... GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING FOR LSZ265>267. GALE WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY AFTERNOON FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...07 MARINE...SRF
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
426 PM CST MON JAN 14 2013 .UPDATE... .DISCUSSION... QUICK UPDATE FOR SOUTHWEST NEBRASKA. THE RUC13 SHOWS AND AREA OF LIGHT SNOW ON THE 285K INSENTROPIC SFC MOVING EAST THIS EVENING. THE NEW FORECAST SLOWS THIS DOWN ABOUT 3 HOURS AND RAISES THE POP TO 50 PERCENT. LESS THAN AN INCH ACCUMULATION IS EXPECTED ALTHOUGH THE RUC SHOWS 3 INCHES. THE RUC IS OFTEN TOO WET. REST OF THE FORECAST IS GOOD. && .PREV DISCUSSION... /ISSUED 245 PM CST MON JAN 14 2013/ SYNOPSIS... IN THE UPPER LEVELS...THE LARGE SCALE CYCLONIC FLOW CONTINUES OVER A LARGE PART OF THE CENTRAL AND WESTERN U.S. RUNNING A 24 HOUR LOOP OF THE IMAGERY...ONE CAN SEE THE DIGGING AND NARROWING OF THE TROUGH. ANALYSIS OF THE 20Z SURFACE DATA REVEALED A WARM FRONT DEVELOPING ACROSS EASTERN MONTANA AND EASTERN WYOMING. SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT. A LOOK AT THE 280-290K LAYER INDICATES SOME WEAK ISENTROPIC LIFT CONTINUING INTO THIS EVENING IN EXTREME SOUTHWEST NEBRASKA. HOWEVER...VERY LITTLE MOISTURE AND ACCUMULATIONS WILL BE HALF AN INCH OR LESS. FOR TUESDAY...A WARM FRONT IS EXPECTED INTO WESTERN NEBRASKA BY EARLY EVENING. AGAIN...IN THE 280-290K LAYER...ISENTROPIC UPGLIDE IS LIKELY TO PRODUCE SOME CLOUDINESS AND POSSIBLY SOME LIGHT SNOW IN THE EVENING AND LIGHT FREEZING DRIZZLE LATE TUESDAY NIGHT AND VERY EARLY WEDNESDAY. MEDIUM RANGE/EXTENDED...WEDNESDAY THROUGH SUNDAY. DRY AND MUCH WARMER WEATHER CAN BE EXPECTED WEDNESDAY THROUGH FRIDAY IN THE AFTERMATH OF THE WARM FRONT. MUCH COLDER WEATHER IS EXPECTED AGAIN AS A BACK-DOOR FRONT COMES ACROSS SATURDAY NIGHT AND SUNDAY. THE FRONT STALLS ALONG THE EASTERN SLOPE OF THE ROCKIES AND SOUTHWEST FLOW WILL PRODUCE ISENTROPIC LIFT AND COULD GIVE SOME POTENTIAL FOR WIDESPREAD SNOW MONDAY AS THE SYSTEM MAKES ITS WAY BACK TO THE EAST-NORTHEAST. AT THAT RANGE... THE UNCERTAINTY IS VERY HIGH REGARDING AMOUNTS AND INTENSITY OF PRECIPITATION. AVIATION... FOR THE 18Z TAF FORECAST CYCLE...GENERAL VFR EXPECTED TODAY ACROSS MOST AREA TERMINALS. THE EXCEPTION BEING ACROSS FAR SOUTHWEST NEBRASKA TODAY...POSSIBLY AFFECTING THE KOGA AND KIML TERMINALS WHERE SCATTERED LIGHT SNOW MAY BRIEFLY REDUCE VISIBILITIES INTO MVFR. MODEL GUIDANCE HAS THE REMAINING LIGHT SNOW DISSIPATING LATER THIS AFTERNOON...IF NOT ALREADY SO...THEREAFTER DRIER AIR ALOFT WILL WORK BACK ACROSS THE REGION...WITH NO VISIBILITY OR CEILING RESTRICTIONS ANTICIPATED. FOR THE OVERNIGHT...NAM SHORT TERM GUIDANCE HINTS AT REDUCED VISIBILITY /DOWN TO 3SM/ AT KLBF AFTER 06Z WITH THE FORMATION OF LOW FOG. FEEL THAT THE SOLUTION IS OVERLY AMBITIOUS WITH THE REMAINING LOW LEVEL MOISTURE...SO WILL NOT INCLUDE A MENTION OF MVFR VISIBILITY IN THE OFFICIAL TAF FORECAST NOW. OTHERWISE BROAD SURFACE HIGH PRESSURE WILL KEEP WIND SPEEDS RELATIVELY LIGHT AND VARIABLE FOR ALL TERMINALS. && .LBF WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM/EXTENDED...CDC AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1233 PM EST MON JAN 14 2013 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL PRODUCE UNSEASONABLY WARM CONDITIONS INTO MID-WEEK. A COLD FRONT WILL MOVE SLOWLY THROUGH THE AREA LATE WEDNESDAY. WEAK GULF COAST LOW PRESSURE MAY BRING A CHANCE OF LIGHT RAIN TO THE REGION THURSDAY NIGHT OR FRIDAY. HIGH PRESSURE WILL BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM MONDAY...HAVE ADJUSTED TEMPS UP A COUPLE OF DEGREES FOR TODAY KEEPING MAX TEMPS IN THE MID TO UPPER 70S. THE SOUTHWESTERLY WINDS WILL BACK A BIT PRODUCING MORE OF AN ON SHORE FLOW THROUGH THE AFTERNOON. THIS WILL KEEP TEMPS COOLER ALONG THE SHORE...MOVING INLAND AS WINDS PICK UP THROUGH THE AFTERNOON. SEA FOG WILL ALSO HELP TO KEEP TEMPS COOLER ALONG THE COAST. PREVIOUS DISCUSSION...MODELS INDICATE THE MID TO UPPER LEVEL RIDGE TO REMAIN ANCHORED JUST OFF THE SE U.S. COAST DURING THIS NEAR TERM PERIOD. THIS WILL SLOW DOWN THE PROGRESSION OF THE BAROCLINIC ZONE IE. THE SFC COLD FRONT...TOWARD THE SOUTHEAST. IN FACT... MODELS ACTUALLY STALL THE COLD FRONT JUST NORTH AND WEST OF THE FA AS IT BECOMES ORIENTED PARALLEL WITH THE FLOW ALOFT. THE DEEPEST MOISTURE WILL REMAIN JUST OUTSIDE OF THE ILM CWA DURING THIS NEAR TERM PERIOD...REMAINING WEST THROUGH NORTH OF THE FA. AMAZINGLY... GFS/NAM/EUROPEAN/ETC. AGREE THAT THIS SCENARIO WILL PLAY OUT. NOW WHAT THEY DO NOT AGREE IS THE THREAT OR PROBABILITY FOR PCPN. WITH THE BEST LIFT REMAINING OUTSIDE OF THE ILM CWA DOMAIN...HAVE INDICATED A LOW CHANCE OF POPS FOR THE NW PORTIONS OF THE FA FROM THIS AFTERNOON THROUGH TONIGHT...ROUGHLY ALONG AND WEST OF THE I-95 CORRIDOR. THE LATEST RUN OF THE HRRR MODEL ALSO INDICATES THIS PCPN POSSIBILITY. HAVE STAYED AWAY FROM MENTIONING THUNDER DUE TO THE LACK OF INSTABILITY ILLUSTRATED BY LATEST NAMBUFR SOUNDINGS...IE. NO CAPE...LI`S STAY MAINLY POSITIVE. WILL LIKELY HAVE A SOMEWHAT OF A SHARP CLOUD GRADIENT ACROSS THE FA WITH THE IMMEDIATE COAST HAVING THE BEST POTENTIAL TO OBSERVE THE DAYS INSOLATION. THEREFORE...HAVE RELIED ON THE WARMER MODEL MOS GUIDANCE FOR BOTH TODAYS MAX AND TONIGHTS MIN TEMPS. THIS WILL RESULT IN ADDITIONAL MAX TEMP RECORDS LIKELY BEING SET FOR 1 MORE DAY. AND FINALLY...THE MID TO UPPER LEVEL CLOUD DECK ACROSS THE FA HAS BEEN OPAQUE ENOUGH TO PREVENT WIDESPREAD RADIATIONAL TYPE DENSE FOG. HOWEVER...SEA FOG IE. ADVECTION TYPE FOG...WILL SPORADICALLY AFFECT THE IMMEDIATE COAST AS SFC WINDS SLIGHTLY BACK TO THE SSW AND PUSH 60+ DEWPOINTS ACROSS SSTS IN THE 50S RESULTING WITH SEA FOG BRIEFLY PUSHING ONSHORE AT TIMES. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 245 AM MONDAY...WEAK FRONT WILL BE STALLED IN OR JUST WEST OF THE REGION FOR A MAJORITY OF THE PERIOD. PROXIMITY TO FRONT WILL CREATE SIGNIFICANT TEMP GRADIENT ACROSS THE REGION...PROVIDING PLENTY OF POTENTIAL FOR THE FORECAST TO GO WRONG. SOME WEAK ISENTROPIC LIFT AND LOW LEVEL MOISTURE MAY PRODUCE SOME PATCHY LIGHT RAIN AT TIMES. ALTHOUGH DRY MID AND UPPER LEVELS WILL LIKELY KEEP MUCH OF THE AREA DRY FOR A MAJORITY OF THE PERIOD. COMBINATION OF FRONT IN THE REGION AND LOW LEVEL CLOUD COVER WILL TEMPER HIGHS ACROSS PORTIONS OF THE FORECAST AREA BOTH DAYS. COASTAL SC ENDS UP WARMEST WITH A LITTLE LESS CLOUD COVER AND SOUTHERLY FLOW INTO WED NIGHT. HIGHS WILL BE IN THE LOW 70S WITH LOWS IN THE UPPER 50S TO AROUND 60. INLAND SC AND NC WILL HAVE BEST PRECIP CHANCES...THOUGH AT THIS POINT LITTLE MORE THAN LOW CHANCE OR SLIGHT CHANCE APPEARS WARRANTED. HIGH TEMP FORECAST WILL BE TRICKY IN THESE AREAS WITH LOCATION OF FRONT...AND THE NORTHERLY FLOW BEHIND IT...LEADING TO A SHARP GRADIENT SOMEWHERE IN THE FORECAST AREA. FOR NOW WILL GO WITH HIGHS NEAR TO ABOVE CLIMO TUE AND ABOVE TO WELL ABOVE CLIMO WED. HOWEVER A MORE EASTERLY POSITION OF THE FRONT WED...SOMETHING GUIDANCE IS TRENDING AWAY FROM...WOULD RESULT IN COOLER TEMPS. LOWS WILL CONTINUE TO RUN ABOVE CLIMO REGARDLESS OF FRONTAL POSITION GIVEN PLENTY OF CLOUD COVER AND LIMITED COLD ADVECTION ON BACKSIDE OF THE BOUNDARY. FRONT IS PULLED OFF THE COAST WED NIGHT BY WEAK SURFACE LOW MOVING INTO THE CANADIAN MARITIMES. LACK OF ANY MID LEVEL PUSH TRANSLATES TO MINIMAL TEMP REDUCTION AS THE PERIOD ENDS. NORTH TO NORTHEAST FLOW ACROSS THE AREA BY END OF PERIOD ONLY DROPS WED NIGHT LOWS A FEW DEGREES. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 245 AM MONDAY...SOUTHERN STREAM SYSTEM EMERGING FROM THE SOUTHWEST MID WEEK WILL BRING THE PERIODS BEST AND ONLY PRECIP CHANCE THU NIGHT INTO FRI. DEEP SOUTHWEST FLOW AHEAD OF THE WAVE AS IT CROSSES THE GULF COAST INCREASES MOISTURE OVER THE SOUTHEAST THU. DIVERGENT PATTERN ALOFT THU NIGHT INTO FRI IS ENHANCED BY 200MB JET STREAK APPROACHING 120 KT. RIGHT NOW THE BIGGEST NEGATIVE FACTOR APPEARS TO BE THE TRACK OF THE MID LEVEL FEATURE AND THE ASSOCIATED SURFACE WAVE. WEAK SURFACE LOW DEVELOPS ALONG FRONT STALLED ACROSS NORTHERN GOMEX EARLY THU. THIS LOW TRACKS NORTHEAST ALONG THE FRONT...PASSING OFF THE SOUTHEAST COAST. THIS KEEPS NORTHEAST LOW LEVEL FLOW IN PLACE FOR THE DURATION OF THE EVENT. BELOW 700MB OR SO FORECAST SOUNDINGS DEPICT A SATURATED BUT VERY STABLE AIR MASS. SO WHILE MID AND UPPER LEVEL FORCING WILL BE PRESENT IT APPEARS THE LOW LEVEL STABILITY WILL ULTIMATELY WIN OUT. THUS HAVE GONE FOR LOWER POP AND MINIMAL QPF EARLY IN THE PERIOD. AS SURFACE AND MID LEVEL FEATURES MOVE OFF TO THE NORTHEAST HIGH PRESSURE BUILDS IN UNDER DEVELOPING PROGRESSIVE MID LEVEL PATTERN. THIS ALLOWS MUCH DRIER AND COOLER AIR TO SPREAD IN FROM THE WEST. PINCHED GRADIENT ALONG THE COAST WILL KEEP NORTHEAST FLOW BRISK INTO SAT MORNING...ESPECIALLY ALONG THE COAST. LATE IN THE PERIOD MEDIUM RANGE GUIDANCE IS TRYING TO SHOW A WEAK COASTAL LOW DEVELOPING ON REMAINS OF STALLED SURFACE BOUNDARY. GIVEN THE TIME RANGE AND POTENTIAL FOR SIGNIFICANT CHANGES REGARDING THIS FEATURE WILL NOT INTRODUCE A POP LATE IN THE PERIOD. TEMPS NEAR CLIMO THROUGH THE PERIOD. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 18Z...STAGNANT SYNOPTIC PATTERN WILL KEEP THE FRONT WEST OF THE REGION...WITH MAINLY THICK HIGH CLOUDS IN AND OUT OF OUR WESTERN TERMINALS. SOUTHWEST FLOW THIS AFTERNOON WILL SHIFT 20-30 DEGREES TO THE SOUTH WITH THE RESULTANT AROUND BEGINNING OF TAF TIME. TONIGHT...FRONT REMAINS WEST OF THE REGION...IT MAY IN FACT RETROGRADE FARTHER WEST. SCATTERED CIRRUS OVERNIGHT WITH A GOOD CHANCE OF FOG/STRATUS AFTER 08Z. TUESDAY...BECOMING VFR BY 14-15Z WITH CONTINUED SOUTHWEST FLOW. EXTENDED OUTLOOK...MORNING FOG/STRATUS EXPECTED AT ALL TERMINALS WEDNESDAY. SLIGHT CHANCE OF SHOWERS WEDNESDAY AFTERNOON. A BETTER CHANCE OF SHOWERS FRIDAY INTO SATURDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1030 AM MONDAY...SFC PRESSURE PATTERN INDICATES THE WESTERN ATLANTIC HIGH...CENTERED OFFSHORE FROM THE SE U.S. COAST...WILL PRODUCE SSW THROUGH WSW WIND DIRECTIONS. THE SFC PG WILL SLIGHTLY TIGHTEN AS THE SFC COLD FRONT APPROACHES FROM THE NW TODAY... BEFORE STALLING BETWEEN DUCK NC SOUTHWEST TO PENSACOLA BEACH FLORIDA TONIGHT. LOOK FOR WIND SPEEDS AT 5 TO 10 KT THIS MORNING...INCREASING TO 10 TO POSSIBLY 15 KT THIS AFTERNOON AND TONIGHT. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT...EXCEPT UP TO 4 FT ACROSS THE OUTER WATERS OFF CAPE FEAR THIS AFTERNOON AND/OR TONIGHT. GENERALLY...A 1 1/2 TO 2 1/2 FOOT ESE GROUND SWELL EXHIBITING 9 TO 12 SECOND PERIODS WILL DOMINATE SIG. SEAS. THE ADDITION OF 3 TO 5 SECOND PERIOD WIND DRIVEN WAVES WILL PUSH SIG. SEAS TO THE 4 FOOT LEVEL OFF CAPE FEAR LATER TODAY AND TONIGHT. SEA FOG WILL ALSO REMAIN A THREAT TO MARINERS THIS FORECAST PERIOD...OCCASIONALLY AND BRIEFLY MOVING ONSHORE. VSBY ROUGHLY 1 NM OR LESS WITHIN THE SEA FOG. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 245 AM MONDAY...SOUTHWEST FLOW REMAINS IN PLACE FOR A MAJORITY OF THE PERIOD WITH SPEEDS GENERALLY 10 TO 15 KT. WEAK SLOW MOVING FRONT DROPPING IN FROM THE NORTH-NORTHWEST LATE IN THE PERIOD WILL BRING ABOUT A WIND SHIFT TO NORTHERLY BY THE END OF THE PERIOD BUT LACK OF COLD ADVECTION OR SIGNIFICANT GRADIENT WILL KEEP SPEEDS LIGHT...10 KT OR LESS. SEAS WILL RUN 2 TO 4 FT THROUGH THE PERIOD...MAINLY AS SOUTHERLY WIND WAVE. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 245 AM MONDAY...NORTH TO NORTHEAST FLOW THU STARTS TO INCREASE THU NIGHT...BUT QUESTION REMAINS BY HOW MUCH. WEAK LOW PRESSURE EMERGING FROM NORTHEAST GOMEX WILL PINCH GRADIENT...BUT HOW TIGHT GRADIENT BETWEEN THIS LOW AND THE HIGH BUILDING IN FROM THE NORTHWEST BECOMES IS UNCERTAIN. ALL OF THE MEDIUM RANGE GUIDANCE DEPICTS THIS SURFACE WAVE PASSING EAST OF THE WATERS LATE THU NIGHT OR EARLY FRI...SO FEEL THAT AN INCREASE IN NORTHEAST FLOW IS LIKELY FOR SECOND HALF OF THE PERIOD. AT THIS POINT CANNOT SAY IF HEADLINES WILL BE NEEDED BUT IT CERTAINLY APPEARS TO BE A POSSIBILITY. CURRENT SEAS FORECAST IS 2 TO 4 FT THU BUILDING TO 3 TO 5 ON FRI. HOWEVER IT IS WORTH NOTING THAT WW3 GUIDANCE IS COMING IN CLOSE TO 10 FT FRI. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RGZ SHORT TERM...III LONG TERM...III AVIATION...DL
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1130 AM CST MON JAN 14 2013 .DISCUSSION.../ISSUED AT 1130 AM CST/ UPDATED THE AFTERNOON GRIDS TO INCLUDE A FEW FLURRIES FOR OUR FAR NORTHERN ZONES ALONG HIGHWAY 14. MID LEVEL CLOUDINESS WILL BE PREVALENT IN THOSE AREAS ASSOCIATED WITH A SLOW MOVING SHORT WAVE. BUT CURRENT THINKING IS THAT LOWER CLOUDS WILL STAY TO THE NORTH OF OUR FORECAST AREA WHICH WOULD AID IN PRODUCING POCKETS OF LIGHT SNOWFALL WHICH COULD MEASURE A LITTLE BIT. /MJF && .AVIATION.../FOR THE 18Z TAF ISSUANCE/ VFR WILL BE THE PRIMARY CATEGORY THIS AFTERNOON...TONIGHT AND TUESDAY MORNING. MID LEVEL CLOUDS WILL STREAM ACROSS OUR FAR NORTHERN ZONES THIS AFTERNOON...AND EVEN SOMEWHAT TONIGHT... ASSOCIATED WITH A MID LEVEL SHORT WAVE WHICH IS MOVING VERY SLOWLY ACROSS THIS AREA. IN ADDITION...SOME LOWER VFR CEILINGS ARE LIKELY TO MOVE NORTHWARD INTO THE SIOUX CITY AND STORM LAKE IOWA AREAS OVERNIGHT AND LATE TONIGHT. THOSE POTENTIAL CLOUDS ARE CURRENTLY EVIDENT IN SOUTHWEST NEB AND NORTHEAST CO. OTHERWISE...WITH A VERY LIGHT SOUTH WIND...SOMETIMES SOME MVFR HAZE OCCURS IN THE MORNING HOURS. SO FOR NOW PUT THAT POSSIBILITY IN A TEMPO GROUP FOR OUR THREE TAF SITES. /MJF && .PREVIOUS DISCUSSION.../ISSUED AT 415 AM CST/ FAIRLY QUIET WEEK AHEAD...WITH MAIN ENERGY FROM A COUPLE OF WAVES EXPECTED TO REMAIN NORTH OF THE AREA...LEAVING TEMPERATURES AS PRIMARY CONCERN THROUGH NEXT WEEKEND. FOR TODAY...WEAK WAVE SLIDING NORTHEAST ACROSS OUR AREA AHEAD OF MID-UPPER TROUGH DROPPING SOUTHEAST INTO THE UPPER MIDWEST. WITH COLD AIR MASS STILL IN PLACE AND WEAK LIFT FROM THIS WAVE...STILL SEEING FLURRIES BEING SQUEEZED OUT OF ANY LOWER/DEEPER MOISTURE LAYERS. RAP SEEMS TO BE HANDLING THE MOISTURE FAIRLY WELL...AND KEEPS DEEPER MOISTURE ACROSS CENTRAL/NORTHERN CWA THIS MORNING... SHIFTING EAST OF THE AREA THROUGH THE AFTERNOON. DEEPER MOISTURE AGAIN LIES IN FAVORABLE TEMPERATURE ZONE FOR ICE PRODUCTION /A FEW DEGREES EITHER SIDE OF -15C/...THUS HAVE ADDED SCATTERED FLURRIES ALONG/NORTH OF I-90 THROUGH MIDDAY. TEMPERATURES SHOULD REBOUND A BIT FROM WEEKEND CHILL AS WARMER LOW LEVEL AIR BEGINS TO WORK INTO THE AREA THIS AFTERNOON. STILL ONE MORE DAY BELOW NORMAL THOUGH... WITH HIGHS IN THE TEENS TO LOWER 20S. ONE THING OF NOTE ON TEMPS THROUGHOUT MUCH OF THE FORECAST... NAM/GFS APPEAR TO HAVE POORLY INITIALIZED SNOW COVER IN THE MODEL... WHICH SEEMS TO BE HAVING A LARGE EFFECT ON THEIR RESPECTIVE SURFACE TEMPERATURE FORECASTS... SEEN BOTH IN THE RAW MODELS/MOS OUTPUT... THOUGH SOMEWHAT LESSER EXTENT IN THE LATTER. THUS HAVE CHOSEN TO FAVOR WARMER GEM/ECMWF TEMPERATURES THROUGH MOST OF THE WEEK... ESPECIALLY THROUGH FRIDAY WHEN WARM AIR ALOFT REMAINS IN PLACE. NEXT WAVE MOVES ACROSS THE REGION TUESDAY/TUESDAY NIGHT. STRONG WARM ADVECTION WILL LEAD TO POTENTIAL FOR A LITTLE LIGHT SNOW OR FLURRIES AHEAD OF THE WARM AIR...WHICH WILL SPREAD ACROSS THE FORECAST AREA IN EARNEST TUESDAY NIGHT. LITTLE ACCUMULATION EXPECTED...WITH MAYBE A QUARTER INCH OR SO ALONG THE HIGHWAY 14 CORRIDOR. STOUT SOUTHWEST FLOW AHEAD OF THE WARM FRONT WILL RESULT IN GUSTY WINDS ATOP AND DOWNSTREAM OF THE BUFFALO RIDGE MUCH OF THE NIGHT. EXPECT EARLY EVENING LOWS FROM AROUND 20 IN THE EAST TO THE MID-UPPER 20S WEST OF THE JAMES VALLEY...WITH MOST AREAS WARMING TO NEAR FREEZING OR JUST SHY BY DAYBREAK WEDNESDAY AS WINDS TURN TO THE WEST BEHIND THE WARM FRONT. STILL LOOKS LIKE A MILD DAY WITH TEMPS ONLY WARMING A FEW MORE DEGREES THROUGH THE DAY TO HIGHS OF 35 TO 45. BACKDOOR COOL FRONT DROPS THROUGH NORTHEAST PORTIONS OF THE FORECAST AREA WEDNESDAY NIGHT/THURSDAY. TEMPERATURES STILL EXPECTED TO BE ABOVE NORMAL THURSDAY THOUGH...WITH HIGHS UPPER 20S NORTHEAST TO THE MID 30S THROUGH THE MISSOURI VALLEY. GEM/ECMWF BOTH SHOWING ANOTHER WARM PUSH FRIDAY AHEAD OF STRONGER PUSH OF COLD AIR EXPECTED NEXT WEEKEND. HAVE NUDGED TEMPERATURES A FEW DEGREES ABOVE GENERAL MODEL CONSENSUS...THOUGH COULD BE EVEN WARMER IF 14/00Z ECMWF PANS OUT. A COUPLE OF QUICK MOVING WAVES DIVE SOUTHEAST ACROSS NORTH DAKOTA AND NORTHERN MINNESOTA DURING THE LONGER RANGE. THE FIRST WEAKER WAVE MOVES THROUGH THURSDAY NIGHT...LEAVING A TIGHTENING THERMAL GRADIENT WHICH NEXT STRONGER WAVE CAN WORK WITH SATURDAY. THIS WAVE WILL PUSH THE ARCTIC FRONT SOUTH THROUGH THE REGION...BRINGING A RETURN TO BELOW NORMAL TEMPERATURES BY THE LATTER HALF OF NEXT WEEKEND. AS WAS MENTIONED ABOVE...ENERGY APPEARS TO REMAIN WELL NORTH OF OUR AREA AT THIS TIME...SO WILL KEEP THE LONGER RANGE DRY FOR NOW. HOWEVER WILL HAVE TO WATCH FOR POTENTIAL OF SOME LIGHT SNOW SUNDAY AS YET ANOTHER WAVE DROPS INTO THE ARCTIC AIR MASS WHICH IS EXPECTED TO PUSH BACK INTO THE REGION BY THEN. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1039 AM CST MON JAN 14 2013 .DISCUSSION.../ISSUED AT 1040 AM CST/ MAINLY TWEAKED THE FORECAST TO REDUCE CLOUD COVER OVER MUCH OF THE FORECAST AREA...MINUS OUR NORTHERN ZONES WHERE MID LEVEL CLOUDINESS SHOULD ADVECT EASTWARD THROUGH THE COURSE OF THE DAY. BUT OTHERWISE THIS AFTERNOON HIGHS SHOULD BE CLOSE. /MJF && .AVIATION.../FOR THE 12Z TAF ISSUANCE/ AN AREA OF CEILINGS 1-3K FEET SHOULD BE EXITING SOUTHWEST MN BY 15Z. OTHERWISE VFR IS EXPECTED OVER THE AREA THROUGH 15/12Z. AREAS OF CEILINGS 3-5K FEET WILL PASS OVER THE AREA NORTH OF INTERSTATE 90 THROUGH 15/06Z WITH CEILINGS ELSEWHERE UNRESTRICTED OR ABOVE 5K FEET. IT APPEARS AIR WILL BE TOO DRY FOR PATCHY FOG IN LIGHT WIND REGIME NEAR END OF PERIOD AT 15/12Z. SURFACE WINDS SHOULD BE 10 KNOTS OR LESS THROUGH 15/12Z. && .PREVIOUS DISCUSSION.../ISSUED AT 415 AM CST/ FAIRLY QUIET WEEK AHEAD...WITH MAIN ENERGY FROM A COUPLE OF WAVES EXPECTED TO REMAIN NORTH OF THE AREA...LEAVING TEMPERATURES AS PRIMARY CONCERN THROUGH NEXT WEEKEND. FOR TODAY...WEAK WAVE SLIDING NORTHEAST ACROSS OUR AREA AHEAD OF MID-UPPER TROUGH DROPPING SOUTHEAST INTO THE UPPER MIDWEST. WITH COLD AIR MASS STILL IN PLACE AND WEAK LIFT FROM THIS WAVE...STILL SEEING FLURRIES BEING SQUEEZED OUT OF ANY LOWER/DEEPER MOISTURE LAYERS. RAP SEEMS TO BE HANDLING THE MOISTURE FAIRLY WELL...AND KEEPS DEEPER MOISTURE ACROSS CENTRAL/NORTHERN CWA THIS MORNING... SHIFTING EAST OF THE AREA THROUGH THE AFTERNOON. DEEPER MOISTURE AGAIN LIES IN FAVORABLE TEMPERATURE ZONE FOR ICE PRODUCTION /A FEW DEGREES EITHER SIDE OF -15C/...THUS HAVE ADDED SCATTERED FLURRIES ALONG/NORTH OF I-90 THROUGH MIDDAY. TEMPERATURES SHOULD REBOUND A BIT FROM WEEKEND CHILL AS WARMER LOW LEVEL AIR BEGINS TO WORK INTO THE AREA THIS AFTERNOON. STILL ONE MORE DAY BELOW NORMAL THOUGH... WITH HIGHS IN THE TEENS TO LOWER 20S. ONE THING OF NOTE ON TEMPS THROUGHOUT MUCH OF THE FORECAST... NAM/GFS APPEAR TO HAVE POORLY INITIALIZED SNOW COVER IN THE MODEL... WHICH SEEMS TO BE HAVING A LARGE EFFECT ON THEIR RESPECTIVE SURFACE TEMPERATURE FORECASTS... SEEN BOTH IN THE RAW MODELS/MOS OUTPUT... THOUGH SOMEWHAT LESSER EXTENT IN THE LATTER. THUS HAVE CHOSEN TO FAVOR WARMER GEM/ECMWF TEMPERATURES THROUGH MOST OF THE WEEK... ESPECIALLY THROUGH FRIDAY WHEN WARM AIR ALOFT REMAINS IN PLACE. NEXT WAVE MOVES ACROSS THE REGION TUESDAY/TUESDAY NIGHT. STRONG WARM ADVECTION WILL LEAD TO POTENTIAL FOR A LITTLE LIGHT SNOW OR FLURRIES AHEAD OF THE WARM AIR...WHICH WILL SPREAD ACROSS THE FORECAST AREA IN EARNEST TUESDAY NIGHT. LITTLE ACCUMULATION EXPECTED...WITH MAYBE A QUARTER INCH OR SO ALONG THE HIGHWAY 14 CORRIDOR. STOUT SOUTHWEST FLOW AHEAD OF THE WARM FRONT WILL RESULT IN GUSTY WINDS ATOP AND DOWNSTREAM OF THE BUFFALO RIDGE MUCH OF THE NIGHT. EXPECT EARLY EVENING LOWS FROM AROUND 20 IN THE EAST TO THE MID-UPPER 20S WEST OF THE JAMES VALLEY...WITH MOST AREAS WARMING TO NEAR FREEZING OR JUST SHY BY DAYBREAK WEDNESDAY AS WINDS TURN TO THE WEST BEHIND THE WARM FRONT. STILL LOOKS LIKE A MILD DAY WITH TEMPS ONLY WARMING A FEW MORE DEGREES THROUGH THE DAY TO HIGHS OF 35 TO 45. BACKDOOR COOL FRONT DROPS THROUGH NORTHEAST PORTIONS OF THE FORECAST AREA WEDNESDAY NIGHT/THURSDAY. TEMPERATURES STILL EXPECTED TO BE ABOVE NORMAL THURSDAY THOUGH...WITH HIGHS UPPER 20S NORTHEAST TO THE MID 30S THROUGH THE MISSOURI VALLEY. GEM/ECMWF BOTH SHOWING ANOTHER WARM PUSH FRIDAY AHEAD OF STRONGER PUSH OF COLD AIR EXPECTED NEXT WEEKEND. HAVE NUDGED TEMPERATURES A FEW DEGREES ABOVE GENERAL MODEL CONSENSUS...THOUGH COULD BE EVEN WARMER IF 14/00Z ECMWF PANS OUT. A COUPLE OF QUICK MOVING WAVES DIVE SOUTHEAST ACROSS NORTH DAKOTA AND NORTHERN MINNESOTA DURING THE LONGER RANGE. THE FIRST WEAKER WAVE MOVES THROUGH THURSDAY NIGHT...LEAVING A TIGHTENING THERMAL GRADIENT WHICH NEXT STRONGER WAVE CAN WORK WITH SATURDAY. THIS WAVE WILL PUSH THE ARCTIC FRONT SOUTH THROUGH THE REGION...BRINGING A RETURN TO BELOW NORMAL TEMPERATURES BY THE LATTER HALF OF NEXT WEEKEND. AS WAS MENTIONED ABOVE...ENERGY APPEARS TO REMAIN WELL NORTH OF OUR AREA AT THIS TIME...SO WILL KEEP THE LONGER RANGE DRY FOR NOW. HOWEVER WILL HAVE TO WATCH FOR POTENTIAL OF SOME LIGHT SNOW SUNDAY AS YET ANOTHER WAVE DROPS INTO THE ARCTIC AIR MASS WHICH IS EXPECTED TO PUSH BACK INTO THE REGION BY THEN. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
331 PM CST MON JAN 14 2013 .TONIGHT AND TUESDAY...FORECAST CONFIDENCE...HIGH AN AREA OF LOW LEVEL CLOUDS WILL LIKELY AFFECT THE NORTHWEST HALF OF THE FORECAST AREA LATE THIS AFTERNOON AND INTO TONIGHT. HIGH LEVEL CLOUDS ARE POSSIBLE ELSEWHERE. THE LOW LEVEL CLOUDS SHOULD MOVE ON OR SCATTER OUT BY LATE IN THE NIGHT...WITH SOME MID LEVEL CLOUDS LINGERING TUESDAY MORNING. SKIES SHOULD BECOME MOSTLY SUNNY BY THE AFTERNOON. LOWS A LITTLE TRICKY TONIGHT...ALL DEPENDING ON HOW LONG CLOUDS STICK AROUND...AS WINDS WILL BE LIGHT. GENERALLY WENT WITH A CONSENSUS FOR LOWS...AS THE ECMWF/GFS/NAM SOLUTIONS NOT TOO FAR APART. COULD SEE TEMPS GET A FEW DEGREES COLDER THAN EXPECTED IF SKIES CLEAR UP SOONER THAN EXPECTED...RESULTING IN A LONGER PERIOD OF GOOD RADIATIONAL COOLING CONDITIONS. HIGH TEMPS SHOULD BE BACK AROUND NORMAL TUESDAY...MAYBE EVEN A DEGREE OR TWO ABOVE AVERAGE VALUES FOR MID JANUARY. .SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY. MID TO UPPER LEVEL TROUGH AXES SHIFT EAST...WITH SHORT WAVE DROPPING SE TUESDAY NIGHT/WEDNESDAY IN LEFT EXIT REGION OF UPPER LEVEL JET MAX TOPPING WESTERN RIDGE AND NOSING INTO THE UPPER MIDWEST. AFTER THIS WAVE CLEARS THE REGION...MODELS VARY IN PLACEMENT OF CHANNELED VORTICITY IN CONFLUENT FLOW UNDER HUDSON BAY POLAR VORTEX FOR THE REST OF THE SHORT TERM BUT GENERALLY KEEP IT TIED TO THE UPPER JET...STAYING NORTH OF FORECAST AREA. TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM. TEMPERATURES FALL TUESDAY EVENING WITH READINGS HOLDING STEADY OR RISING AFTER LOWS ARE REACHED AROUND MIDNIGHT AS SOUTHWEST WINDS INCREASE AHEAD OF APPROACHING SHORT WAVE. LOCATION OF BEST FORCING WITH WAVE VARIES WITH MODEL TRACK AND STRENGTH DIFFERENCES. CONSENSUS KEEPS THE BETTER CHANCES FOR ACCUMULATING SNOW ACROSS NRN WI...WHICH LEADS TO CHANCE OF LIGHT SNOW IN THE FAR NORTH AND SLIGHT CHANCE ELSEWHERE MAINLY WEDNESDAY MORNING. BRIEF PERIOD OF LIFT AND DEEP MOISTURE INTO THE DENDRITE GROWTH ZONE...ALONG WITH PRECIPITABLE WATER ONLY REACHING 1/3 INCH SO DURING MOST FAVORABLE TIME FOR PRECIPITATION...MEANS MINIMAL ACCUMULATIONS OF A FEW TENTHS OF AN INCH AT MOST. GUSTY WINDS ON WEDNESDAY WITH TIGHT GRADIENT AROUND SOUTHERN CANADA LOW. AGAIN A CONSENSUS BLEND TEMPERING THE STRONGER NAM WINDS BUT THIS STILL BRINGS 15 TO 25 MPH SOUTHWEST WINDS...SHIFTING WEST BEHIND THE SURFACE TROUGH/COLD FRONT...WITH A FEW GUSTS TO 30 MPH. THE GUSTY SOUTHWEST WINDS PUSH A THERMAL RIDGE AHEAD OF SURFACE TROUGH OVER THE CWA MIDDAY...WITH BLENDED TEMPERATURES BRINGING HIGHS IN THE LOWER TO MIDDLE 30S...THOUGH TEMPS COULD BE LOWER IF FASTER MOVEMENT OF COLD FRONT REFLECTED IN THE GFS AND GEMNH OCCURS. WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH. WEST-NORTHWEST FLOW BEHIND LOW SHUNTS COLDEST AIR OFF TO THE NORTHEAST OF THE REGION OVER SOUTHEAST CANADA...BUT ENOUGH COLD AIR ADVECTION TO BRING SINGLE DIGIT LOWS TO THE NORTH WEDNESDAY NIGHT...WITH MID-TEENS IN THE SOUTH. HIGH PRESSURE BRINGS QUIET WEATHER WITH NEUTRAL TEMPERATURE ADVECTION BRINGING HIGHS IN THE TEENS NORTH TO LOWER 20S SOUTH. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE LOW TO MEDIUM. WEAK WAVES PASSING BY TO THE NORTH IN THE NEAR ZONAL FLOW LIFT 850/925MB TEMPERATURES ENOUGH TO WARM HIGHS INTO THE LOWER TO MIDDLE 30S FOR FRIDAY AND SATURDAY. FAR NORTH MAY BE BRUSHED BY LIGHT SNOW WITH THE WARM ADVECTION PUSH THURSDAY NIGHT...AND ONLY A LITTLE BETTER CHANCE SATURDAY/SATURDAY NIGHT WITH STRONGER WAVE CROSSING NORTHERN WISCONSIN. COLD ADVECTION AROUND ARCTIC HIGH SETTLING INTO THE PLAINS BEHIND THIS LAST WAVE BRINGS HIGHS IN THE TEENS SUNDAY...WITH SINGLE DIGIT LOWS SUNDAY NIGHT. BLENDED HIGHS ON LY IN THE SINGLE DIGITS TO LOWER TEENS MONDAY...THEN FALLING TO BELOW ZERO AWAY FROM LAKE MICHIGAN MONDAY NIGHT. IF COLDER GFS PANS OUT...READINGS COULD GET EVEN COLDER. && .AVIATION/00Z TAFS/... STILL WATCHING AN AREA OF MVFR CIGS UPSTREAM. LATEST RAP AND NAM RH FIELDS INDICATE THIS MAY HOLD TOGETHER AND MOVE INTO THE NORTHWEST HALF OF THE FORECAST AREA MID TO LATE THIS AFTERNOON. BEST CHANCE FOR THESE LOWER CIGS APPEARS TO BE ROUGHLY ALONG AND NORTHWEST OF A MINERAL POINT TO SHEBOYGAN LINE...AS THE HIGH RH IN THE MODELS NEVER QUITE MAKES IT TO THE SOUTHEAST. WILL CONTINUE TO KEEP AN EYE ON SATELLITE TRENDS AND MODIFY TAFS AS NEEDED. ANY LOWER CIGS SHOULD SCATTER OUT OR MOVE OUT BY MORNING...WITH VFR CONDITIONS THEN EXPECTED THROUGH THE DAY TUESDAY. && .MARINE... SOUTHWEST WINDS WILL INCREASE TUESDAY NIGHT AHEAD OF AN APPROACHING TROUGH OF LOW PRESSURE. WIND GUSTS ARE EXPECTED TO PEAK IN THE 30-35 KT RANGE LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING. MODELS CURRENTLY INDICATING GUSTS RIGHT ON THE VERGE OF GALE FORCE...ESPECIALLY TOWARD OPEN WATERS...SO WILL GO WITH A GALE WATCH FOR THIS PERIOD OF HIGHER GUSTS. WILL LIKELY SEE GUSTS TO SMALL CRAFT LEVELS EARLIER IN THE NIGHT AS THINGS RAMP UP...AND INTO WEDNESDAY AFTERNOON AS WINDS EASE. THE HIGHEST WAVES WILL BE ACROSS THE NORTH AND TOWARD OPEN WATERS DUE TO THE EXPECTED SOUTHWEST FLOW. NOT EXPECTING WAVES WILL GET PARTICULARLY HIGH GIVEN THE OFFSHORE COMPONENT TO THE WINDS. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...GALE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING FOR LMZ643>646. && $$ TONIGHT/TUESDAY AND AVIATION/MARINE...DDV TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1128 AM CST MON JAN 14 2013 .SHORT TERM...TODAY THROUGH WEDNESDAY 322 AM CST MON JAN 14 2013 AT 3 AM...A SURFACE TROUGH WAS LOCATED ACROSS SOUTHWEST MINNESOTA. THIS TROUGH IS CURRENTLY PRODUCING A MVFR DECK OF CLOUDS ACROSS EASTERN SOUTH DAKOTA AND SOUTHWEST MINNESOTA. THERE ARE EVEN FLURRIES BEING REPORTED AT SIOUX FALLS SOUTH DAKOTA. FURTHER TO THE SOUTHWEST...THE WATER VAPOR IMAGERY SHOWS A SHORT WAVE TROUGH MOVING OUT OF COLORADO. THIS SYSTEM HAS BEEN PRODUCING SOME LIGHT SNOW FROM COLORADO INTO CENTRAL SOUTH DAKOTA. THE 14.00Z MODELS ARE IN GOOD AGREEMENT THAT THE SURFACE TROUGH WILL MOVE SLOWLY EAST AND GRADUALLY WEAKEN TODAY. MEANWHILE THE SHORT WAVE WILL MOVE ACROSS THE AREA THIS AFTERNOON. BOTH THE GFS AND NAM/WRF SOUNDINGS SHOW LITTLE OMEGA WITH THESE SYSTEMS. MEANWHILE THE RAP HAS UP TO 5 MICROBARS OF OMEGA CO-LOCATED WITH THE DENDRITIC GROWTH ZONE. SINCE BOTH SYSTEMS ARE CURRENTLY PRODUCING SOME FLURRIES OR VERY LIGHT SNOW...WENT MORE TOWARD THE RAP AND INTRODUCED SOME SCATTERED FLURRIES FOR THIS AFTERNOON NORTHWEST OF SAINT ANSGAR IOWA TO WISCONSIN RAPIDS LINE. ON TUESDAY NIGHT AND WEDNESDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE SYSTEM WILL MOVE ALONG THE ARCTIC COLD FRONT TO OUR NORTH. AS THE WAVE APPROACHES...THE CLOUDS WILL INCREASE OVERNIGHT AND TEMPERATURES WILL SLOWLY RISE. LIKE THE PAST COUPLE OF DAYS...THE MODELS CONTINUE TO SHOW THAT THERE WILL BE ENOUGH MOISTURE FOR SOME PRECIPITATION TO DEVELOP ALONG AND NORTH OF THE INTERSTATE 90 CORRIDOR OVERNIGHT TUESDAY AND WEDNESDAY MORNING. HOWEVER SOUNDINGS CONTINUE TO STRUGGLE ON WHETHER THERE WILL BE ICE CRYSTAL SEEDING OR NOT. IN MANY CASES...WHERE THEY SHOW THE LACK OF ICE...THERE IS NO PRECIPITATION. SINCE THERE IS NO CLEAR SIGNAL...JUST KEPT THE PRECIPITATION IN THE FORM OF SNOW FOR NOW. HOWEVER A BIT CONCERNED THAT THERE MAY BE SOME LIGHT FREEZING DRIZZLE ON THE SOUTHERN PERIPHERY OF THE PRECIPITATION. ANOTHER CONCERN ON WEDNESDAY IS THE TEMPERATURES...THE NAM/WRF HAS WAY TOO MUCH SNOW COVER IN IT. THIS MODEL SHOWED 1 TO 2 INCHES OF SNOW ON THE GROUND ACROSS NORTHEAST IOWA AND SOUTHEAST MINNESOTA...AND 2 TO 5 INCHES OF SNOW ACROSS WESTERN WISCONSIN. COOPERATIVE REPORTS AND NOHRSC SHOW THAT WITH THE EXCEPTION OF AN INCH AT MEDFORD WISCONSIN...MUCH OF THE AREA IS SNOW FREE. DUE TO THIS...THE NAM/WRF TEMPERATURES ARE WAY TOO COLD. TYPICALLY...AT LA CROSSE THE MID-JANUARY MAXIMUM TEMPERATURES AVERAGE 10 DEGREES WARMER THAN THE LONG TERM AVERAGE /24.7 DEGREES AT KLSE/ WHEN THERE IS NO SNOW ON THE GROUND. THIS FITS IN WELL WITH A BLEND OF THE GFS/ECMWF/GEM. WOULD NOT BE SURPRISED TO SEE SOME LOWER 40S ACROSS SOUTHWEST WISCONSIN AND NORTHEAST IOWA. .LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY 322 AM CST MON JAN 14 2013 ON THURSDAY AND THURSDAY NIGHT...THE 14.00Z MODELS CONTINUE TO STRUGGLE ON HOW FAR SOUTH THE ARCTIC FRONT WILL GET. THE GFS HAS THIS FRONT DROPPING SOUTH OF THE FORECAST AREA. MEANWHILE THE NAM/WRF KEEPS THIS FRONT NORTH OF THE FORECAST AREA. THIS IS DUE TO ANOTHER LOW PRESSURE SYSTEM QUICKLY FOLLOWING THE LOW THAT PASSES TO THE NORTH OF THE AREA ON TUESDAY NIGHT AND WEDNESDAY. MEANWHILE THE ECMWF IS A GOOD COMPROMISE BETWEEN THE TWO AND IT HAS THIS FRONT ONLY GETTING AS FAR SOUTH AS THE INTERSTATE 94 CORRIDOR. DUE TO THESE DIFFERENCES...THERE IS LOWER THAN USUAL CONFIDENCE IN THE TEMPERATURES. EVEN THE SNOWFALL FORECAST IS UNCERTAIN DUE TO THE VARIOUS TIMING OF THE WAVES AND THE PLACEMENT OF THE FRONT /THE SNOW WILL BE MAINLY CONFINED NORTH OF THIS FRONT/. ON FRIDAY...THE MODELS CONTINUE TO SHOW THAT A LOW PRESSURE AREA WILL BE PASSING NORTH OF THE AREA. THE COMBINATION OF SOUTHWEST WINDS AND SUNSHINE WILL ALLOW TEMPERATURES TO ONCE AGAIN WARM INTO THE 30S AND LOWER 40S. THE ECMWF EVEN SUGGESTS LOWER AND MID 40S. SINCE THIS HAS BEEN A CONSISTENT SIGNAL...RAISED THE ALL BLEND TEMPERATURES BY ABOUT 5 DEGREES. ON SUNDAY...THE MODELS CONTINUE TO STRUGGLE ON HOW FAR SOUTH THE ARCTIC FRONT WILL SAG SOUTHWARD INTO THE AREA. A COUPLE OF DAYS AGO THE ECMWF CONSISTENTLY SHOWED THAT THIS FRONT WOULD MOVE WELL SOUTH OF THE AREA. THE 13.12Z ECMWF BACKED AWAY FROM THIS SOLUTION...AND THE 14.00Z ECMWF HAS RETURNED BACK TO ITS COLDER SOLUTION. SINCE THERE IS SOME UNCERTAINTY ON WHERE THIS FRONT WILL BE LOCATED AND CONCERN ABOUT HOW MUCH MODERATION MAY TAKE PLACE WITH THE LACK OF SNOW ACROSS THE AREA...JUST STAYED WITH THE ALL BLEND FORECAST FOR NOW. && .AVIATION...THROUGH 18Z TUESDAY 1128 AM CST MON JAN 14 2013 WEAK MID-LEVEL TROUGH WAS PUSHING BROKEN DECK OF VFR/MVFR STRATOCUMULUS INTO THE AREA LATE THIS MORNING. EXPECT THIS CLOUD TO LINGER THIS AFTERNOON WITH SCATTERED LIGHT FLURRY ACTIVITY. PLAN ON THE CLOUDS TO ERODE THIS EVENING WITH LOSS OF SURFACE HEATING AND INCREASING LOW-LEVEL SUBSIDENCE. VFR CONDITIONS THEN EXPECTED THROUGH THE OVERNIGHT HOURS AND THROUGH TUESDAY AS SURFACE HIGH PRESSURE BUILDS OVERHEAD. && .ARX WATCHES/WARNINGS/ADVISORIES... 322 AM CST MON JAN 14 2013 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...DAS