Forecast Discussions mentioning any of "HRRR" "RR" "RUC13" "RUC" received at GSD on 02/19/12


AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
339 PM EST FRI FEB 17 2012 .SHORT TERM... AREA OF ISENTROPIC LIFT AHEAD OF APPROACHING CLIPPER SYSTEM WAS GENERATING AN AREA OF LIGHT SNOW JUST TO OUR NORTH THIS AFTERNOON. REGIONAL RADAR MOSAIC COUPLED WITH HIGH RES GUIDANCE SUGGEST THIS WILL REMAIN JUST NORTH OF FORECAST AREA EARLY THIS EVENING. HOWEVER...AS SURFACE LOW DROPS SOUTH AND EAST LIGHT PCPN WILL AGAIN BE POSSIBLE AND HRRR SHOWS THIS AFTER ABOUT 01Z. WILL MAINTAIN A LOW CHANCE POP FOR THIS LIGHT PRECIPITATION POSSIBILITY ACROSS THE FAR NORTH AS MOISTURE AHEAD OF THIS SYSTEM REMAINS LIMITED. AS LOW PASSES AND COLD AIR ADVECTION DEVELOPS SHOULD SEE AN INCREASE IN LOW AND MID LEVEL MOISTURE WITH AID OF LAKE MICHIGAN. DELTA T VALUES INCREASE TO LOWER TEENS WHICH SHOULD BE ENOUGH TO HELP IN LAKE CLOUD GENERATION AND SOME LIGHT SNOW SHOWERS IN THE NORTH. ANY ACCUMS EXPECTED TO BE LIGHT AND WILL DEPEND ON DEPTH OF MOISTURE COLUMN. HIGH PRESSURE QUICKLY MOVES IN ON SATURDAY WITH CLEARING SKIES IN AFTERNOON AS FLOW VEERS. INCREASE IN HIGH CLOUDS POSSIBLE SATURDAY NIGHT AS SOUTHERN STREAM SYSTEMS DEEPENS AND SPREADS HIGH LEVEL MOISTURE NORTH. PRECIPITATION EXPECTED TO REMAIN WELL SOUTH OF FORECAST AREA. && .LONG TERM... SUNDAY THROUGH FRIDAY... PLEASANT WEATHER PATTERN TO BEGIN THE FORECAST PERIOD WITH SFC HIGH PRESSURE CENTERED OVER THE GREAT LAKES REGION ON SUNDAY THEN DRIFTING SE INTO OH VALLEY ON MONDAY. AFTER SEASONABLE TEMPERATURES ON SUNDAY WILL SEE A WARMUP TO BEGIN NEXT WEEK AS MID LEVEL RIDGING BUILDS EASTWARD INTO THE AREA IN RESPONSE TO STRONG JET DYNAMICS COMING ONSHORE IN PACIFIC NW WHICH WILL REINFORCE TROUGH OVER FOUR CORNERS. MEDIUM RANGE MODELS OFFERING VARIED SOLNS IN HANDLING ENERGY EJECTING OUT OF TROUGH...BUT ALL INDICATIONS POINT TO PERIOD OF UNSETTLED WEATHER MIDDLE PORTION OF NEXT WEEK. ONE COMMON THEME AND AN AREA OF HIGHER CONFIDENCE AMONG THE MODELS IS THE PHASING OF NORTHERN AND SOUTHERN STREAMS AND SUBSEQUENT BROAD LONGWAVE TROUGH CARVED OUT FROM THE PLAINS TO GREAT LAKES REGION THURSDAY-FRIDAY TIMEFRAME. WHILE TIMING AND DETAILS OF RESULTING SENSIBLE WEATHER REMAIN UNCERTAIN...PATTERN SUGGESTS KEEPING POPS IN FCST TUE-THU AND ABSENCE OF ANY SIGNS OF SFC RIDGING BUILDING IN BEHIND THIS SYSTEM FAVORS CONTINUED CYCLONIC FLOW AND SMALL CHANCE POPS FRI AS WELL.&& .AVIATION... MID LEVEL CLOUDS SHOULD INCREASE AT KSBN THROUGH THE AFTERNOON AND AT KFWA LATER THIS EVENING AS SHORT WAVE MOVES BY TO THE NORTH. VFR CONDITIONS EXPECTED REST OF TODAY AND THIS EVENING. AS SURFACE LOW PASSES TO THE NORTH AND FLOW BECOMES NORTHWEST OVERNIGHT SHOULD SEE LAKE CLOUD DEVELOPMENT. MODEL SOUNDINGS SUGGEST MVFR CIGS AT KSBN TOWARD DAYBREAK. PCPN EXPECTED TO BE LIGHT AND MAINLY NORTH OF TAF SITES BUT KSBN WILL BE ON SOUTHERN FRINGE. COULD SEE SOME FLURRIES WITH LAKE CLOUDS AND COLD AIR ADVECTION EARLY SAT MORNING. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...LASHLEY LONG TERM...LOGSDON AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS DES MOINES IA
330 PM CST FRI FEB 17 2012 .SHORT TERM /TONIGHT/... LATEST WV IMAGERY WITH H500 RUC ANALYSIS SHOWED CONFLUENT UPPER LEVEL FLOW ACROSS THE MISSOURI RIVER VALLEY ONCE AGAIN...WITH ANOTHER WEAK SHORTWAVE APPROACHING THE MT/ND BORDER. A STRIP OF POSITIVE VORTICITY ORIENTED EAST/WEST FROM CENTRAL SOUTH DAKOTA THROUGH CENTRAL WISCONSIN IS A RESULT OF SPEED SHEAR ASSOCIATED WITH THE ZONAL FLOW TO THE SOUTH...AND NORTHERLY FLOW TO THE NORTH. THIS FEATURE WILL REMAIN FAIRLY TRANSIENT...SO WITH LITTLE PVA...IT SHOULD HAVE LITTLE IMPACT ON THE SURFACE. IN ADDITION...SUBSIDENCE ASSOCIATED WITH THE LEFT ENTRANCE REGION OF THE UPPER LEVEL JET AND THE ANTICYCLONIC CURVATURE OF THE UPPER LEVEL FLOW WILL CAUSE A SURFACE HIGH PRESSURE TO BUILD INTO CENTRAL IOWA AS SHOWN IN THE 6HR SURFACE ISALLOBARIC MAP. THIS SURFACE HIGH WILL REDUCE WINDS OVERNIGHT...WHICH COULD ALLOW TEMPS TO FALL OFF. HOWEVER...CELLULAR STRATUS DECK SPREADING ACROSS ALL OF MINNESOTA COULD LIMIT THE RADIATIONAL COOLING IF IT HOLDS TOGETHER AFTER SUNSET AND MOVES INTO NORTHERN IOWA. FORECAST SOUNDINGS AND TIME/HEIGHT CROSS SECTIONS SHOW THIN LAYER OF HIGH RH IN THE LOWEST LEVELS OF THE BOUNDARY LAYER. ANTICIPATING THIS TO TAKE SHAPE AS MORE OF A SCATTERED VS BROKEN DECK OF CLOUDS...SO HAVE KEPT LOW TEMPS IN THE TEENS ACROSS THE NORTHWESTERN CWA...WITH WARMER TEMPS IN THE SOUTHEAST. .LONG TERM /SATURDAY THROUGH FRIDAY/... LITTLE CHANGE IN THE OVERALL LONG TERM FORECAST WITH TIMING AND PLACEMENT DETAILS OF ATMOSPHERIC FEATURES REMAINING CONSISTENT THE PAST FEW DAYS. TEMPERATURES THIS WEEKEND WILL BE NEAR TO A LITTLE ABOVE SEASONAL VALUES THOUGH SHOULD BE ABOVE GUIDANCE VALUES. DRY CONDITIONS WILL PREVAIL THROUGH THE WEEKEND. WELL ADVERTISED UPPER LEVEL SYSTEM IS STILL ON TRACK TO IMPACT THE STATE MONDAY THROUGH EARLY TUESDAY. PRECIPITATION TYPE DUE TO SOME UNCERTAINTY OF LOW LEVEL TEMPERATURE PROFILE REMAINS THE PRIMARY CHALLENGE WITH THE SYSTEM. THE PAST SEVERAL EVENTS IN ADDITION TO LOW LEVEL FORECAST PROFILES SUGGEST THE PRECIPITATION WILL BE MAINLY RAIN FOR THE SOUTHERN HALF TO TWO-THIRDS OF THE FORECAST AREA. THE PRECIPITATION TYPE BECOMES MUCH MORE PROBLEMATIC OVER NORTHERN IOWA. VERY WELL COULD HAVE A TRANSITION ZONE TO ALL SNOW OVER THE NORTHERN FEW TIER OF COUNTIES AND COULD RESULT IN MODERATE SNOWFALL ACCUMULATIONS. WILL ADD THE POTENTIAL TO THE HWO. ANOTHER SHORTWAVE STILL ON TRACK MID NEXT WEEK. PROFILES ARE A BIT COLDER WITH THIS SYSTEM AND COULD RESULT IN A MORE WIDESPREAD LIGHT SNOW EVENT. LOW PRECIPITATION CHANCES AROUND TO END THE FORECAST PERIOD HOWEVER ANYTHING THAT WOULD OCCUR WOULD BE QUITE LIGHT. && .AVIATION...17/18Z A COLD FRONT IS MOVING SOUTHEAST ACROSS THE STATE...AND IS MOST EVIDENT BY THE WIND SHIFT FROM SOUTHWEST TO NORTHWEST AS IT PASSES THROUGH. A THIN STRATUS DECK CURRENTLY LOCATED OVER THE DAKOTA/MINNESOTA BORDER IS HEADING TOWARD NORTHERN IOWA...BUT STILL UNSURE IF THIS WILL HOLD TOGETHER BY THE TIME IT ARRIVES THIS EVENING. THEREFORE JUST HAVE SCATTERED DECK IN THE TAF. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...BEITLICH LONG TERM...DONAVON AVIATION...BEITLICH
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1156 PM CST THU FEB 16 2012 ...UPDATED AVIATION DISCUSSION... .SHORT TERM /TONIGHT/... LATEST WV IMAGERY WITH H500 RUC ANALYSIS SHOWED CONFLUENT UPPER LEVEL FLOW ACROSS THE MISSOURI RIVER VALLEY...WITH A WEAK SHORTWAVE APPROACHING THE MT/ND BORDER. SURFACE ANALYSIS DEPICTED 1025MB HIGH CENTERED OVER KS/MO BORDER...WITH A NORTH/SOUTH ORIENTED TROUGH LOCATED OVER THE CENTRAL DAKOTAS IN ASSOCIATION WITH THE AFOREMENTIONED SHORTWAVE. AS THE WEAK UPPER LEVEL WAVE MOVES SOUTHEAST ACROSS THE DAKOTAS OVERNIGHT...AND THE SURFACE HIGH MEANDERS EASTWARD...THE LOW LEVEL WINDS WILL GRADUALLY BACK FROM THE WEST TOWARD THE SOUTHWEST OVERNIGHT. THEY SHOULD REMAIN STRONG ENOUGH TO MITIGATE ANY WIDESPREAD DENSE FOG. HOWEVER...TIME HEIGHT CROSS SECTIONS SHOW SOME LOW LEVEL MOISTURE DEVELOPING BY MORNING...SO FEEL THAT PATCHY FOG IS POSSIBLE...ESPECIALLY ACROSS SNOW COVERED AREAS. FOR OVERNIGHT LOW TEMPS WENT WITH THE BIAS-CORRECTED GUIDANCE. .LONG TERM /FRIDAY THROUGH THURSDAY/... FORECAST CHALLENGE THROUGH THE PERIOD REMAINS THE UPPER LEVEL SYSTEM IMPACTING THE MIDWEST EARLY NEXT WEEK. BEFORE THEN...SHORT WAVE ENERGY DROPPING SOUTHEAST THROUGH ERN MONTANA/WRN NORTH DAKOTA WILL PUSH THROUGH FRIDAY MORNING. GOOD KINEMATICS AND A PUSH OF TEMPERATURE ADVECTION WILL ARRIVE WITH THE SYSTEM. THE SYSTEM WILL BE LACKING MOISTURE HOWEVER. THAT SAID...IT APPEARS TO BE A SMALL WINDOW WITH FLURRIES OR WORST CASE SCENARIO A LIGHT SNOW SHOWER TO MOVE THROUGH INTO MID MORNING. A SFC BOUNDARY WILL MOVE THROUGH DURING THE DAY ON FRIDAY AS WELL. IT WILL NOT REACH THE SOUTHEAST UNTIL THE AFTERNOON...THEREFORE A GOOD WARMUP AHEAD OF BOUNDARY IS POSSIBLE. THE COLD ADVECTION WILL BE FOCUSED NEAR 925 MB WITH THE SFC IMPACT LAGGING. WITH THIS...MIXING WILL OCCUR AND LIMIT THE SFC IMPACT ON TEMPERATURES DURING THE DAY. ANOTHER BOUNDARY WILL DROP SOUTH FRIDAY NIGHT AND WILL LEAD TO A COOLER YET DRY WEEKEND. STILL A COMPLEX SITUATION EARLY NEXT WEEK WITH AN ACTIVE FLOW AND NUMEROUS PIECES OF ENERGY MOVING THROUGH THE LONG WAVE TROUGH. THE FOCUS IS ON THREE OF THE EMBEDDED IMPULSES WITH ONE NORTH INTO CANADA...ONE IMPACTING THE MIDWEST AND ANOTHER DROPPING WELL TO THE SOUTH. EACH COULD CERTAINLY IMPACT THE OTHERS REGARDING TIMING AND PLACEMENT BUT AT THIS TIME...SOME CONSENSUS DEVELOPING REGARDING EACH. FOCUS FOR PRECIPITATION WILL BE LATE MONDAY THROUGH EARLY TUESDAY. TRENDS ARE SUGGESTING THE PRECIPITATION COULD BE MOSTLY SNOW OVER THE NORTH WITH A MIX OR EVEN ALL RAIN TO THE SOUTH. THE FLOW WILL REMAIN ACTIVE FOR THE REMAINDER OF THE EXTENDED WITH ADDITIONAL POTENTIAL FOR PRECIPITATION AND TEMPERATURES GENERALLY NEAR TO ABOVE SEASONAL VALUES. && .AVIATION...17/06Z VFR CONDITIONS WILL PREVAIL THROUGH THE ENTIRE TAF PERIOD. HAD LOW CONFIDENCE WITH MENTION OF FOG DEVELOPING OVERNIGHT TONIGHT AND TOOK MENTION OUT ATTM. WINDS WILL SHIFT TO THE SOUTHWEST FOR A SHORT WHILE BEFORE THE WEAK COOL FRONT/TROUGH PUSHES THROUGH EARLY FRIDAY MORNING. MIXING DEVELOPS BY AROUND MIDDAY AND SHOULD SEE A FEW GUSTS NEAR 20KTS FRIDAY AFTERNOON. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...BEITLICH LONG TERM...DONAVON AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS CARIBOU ME
600 AM EST FRI FEB 17 2012 .SYNOPSIS... AN OCCLUDED FRONT WILL CROSS THE REGION TODAY INTO TONIGHT. HIGH PRESSURE WILL THEN SLOWLY BUILD EAST SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... UPDATE...ADJUSTED THE TIMING OF PRECIP TO ACCOUNT MORE FOR THE LATEST RADAR TRENDS WHICH SHOW PRECIP MOVING FASTER TO THE NE THAN EARLIER EXPECTED. ALSO INCREASED PERCENTAGES UP TO NEAR 100% WHERE PRECIP IS OCCURRING. HRLY TEMPS WERE ADJUSTED AND ALSO RAISED THE MAXES FOR TODAY UP A FEW DEGREES EVEN AS FAR NORTH AS THE SAINT JOHN VALLEY. .PREVIOUS DISCUSSION... THE CHALLENGE WILL BE SNOWFALL AND TEMPERATURES. SHORT RANGE MODEL GUIDANCE IS RUNNING TOO COLD ATTM PER THE LATEST OBS BY AT LEAST 2-4 DEGREES. THE GFS AND RUC MATCHED WELL W/THE 00Z UA SHOWING WARMER AIR MAKING ITS WAY FURTHER NORTH INTO NE AROOSTOOK COUNTY THIS AFTERNOON. RADAR WAS SHOWING LIGHT PRECIP IN THE FORM OF RAIN MOVING ACROSS THE INTERIOR SECTIONS OF DOWNEAST MAINE WHILE LIGHT SNOW IS BREAKING OUT ACROSS THE CENTRAL REGIONS. THAT WARMER AIR WILL CONTINUE TO STREAM NE LATER THIS MORNING W/SNOW MIXING W/& CHANGING OVER TO RAIN OVER THE CENTRAL AREAS AND THEN THE MIX OR EVEN CHANGEOVER TO RAIN ACROSS THE NORTHERN AREAS BY AROUND 18Z. ACROSS THE SAINT JOHN VALLEY, TEMPERATURES WILL BE RIGHT AROUND THE CRITICAL TEMPERATURES OF 32-33F W/PRECIP MAINLY IN THE FORM OF SNOW. QPF WILL BE LESS THAN .25" FOR THIS EVENT W/THE HIGHEST TOTAL OVER THE EASTERN CORRIDOR OF MAINE & MAINLY IN THE FORM OF RAIN. SNOW RATIOS ACROSS THE NORTH WILL BE IN A RANGE OF 10-11:1 AND THEN DROP BACK TO LESS THAN 10:1 BY LATE MORNING AS THE LLVLS WARM. THIS WILL CUT DOWN ON ACCUMULATIONS. STAYED W/SNOWFALL AMOUNTS OF 1-2 INCHES AND THIS WILL MAINLY BE NORTH AND WEST OF CARIBOU AND PRESQUE ISLE. THERE COULD BE A PERIOD OF MODERATE TO HEAVY SNOWFALL AS SOME MID LEVEL INSTABILITY IS SHOWN BY THE GFS TO TAKE PLACE FROM 12-18Z. HIGH TEMPERATURES TODAY WILL BE IN THE LOW TO MID 30S ACROSS THE NORTH W/UPPER 30S TO LOWER 40S ACROSS DOWNEAST AND THE COAST. FOR TONIGHT, OCCLUSION IS FCST TO SLIDE INTO NEW BRUNSWICK THIS EVENING W/STEADY PRECIP ENDING AND COOLER AIR FILTERING INTO THE REGION. AIRMASS STARTS TO DRY OUT TONIGHT MAINLY ACROSS THE CENTRAL AND DOWNEAST REGION W/SOME CLEARING. FURTHER NORTH, BRIEF CLEARING WILL GIVE WAY TO CLOUDS AS UPPER TROF MOVES ACROSS THE REGION. SOME WEAK FORCING IS THERE IN THE MID LEVELS TO TRIGGER SOME LIGHT SNOW/SNOW SHOWERS. STAYED W/20-30% POPS AND LEANED CLOSE TO THE PREVIOUS LOWS OF UPPER TEENS/LOWER 20S ACROSS THE NORTH AND WEST TO LOW TO MID 20S FOR THE CENTRAL AND DOWNEAST REGION. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... INTENSIFYING LOW PRESSURE WILL LIFT THROUGH THE CANADIAN MARITIMES ON SATURDAY WITH GUSTY WEST WINDS EXPECTED. OUTSIDE OF ANY SCATTERED SNOW SHOWERS OR FLURRIES ACROSS NORTHWEST AREAS EXPECT PARTLY SUNNY SKIES ACROSS THE NORTH AND MOSTLY SUNNY SKIES DOWNEAST. A FAST MOVING SHORT WAVE FROM THE EASTERN GREAT LAKES WILL MOVE ACROSS NEW ENGLAND LATER SATURDAY AND SATURDAY NIGHT. ANY SNOW SHOWERS WITH THIS SYSTEM WILL REMAIN TO OUR SOUTH WITH MAINLY CLEAR TO PARTLY CLOUDY SKIES EXPECTED ACROSS THE REGION. HIGH PRESSURE WILL BUILD TOWARD THE REGION ON SUNDAY WITH PARTLY TO MOSTLY SUNNY SKIES EXPECTED. HIGHS ON SATURDAY WILL RANGE THE UPR 20S TO LWR 30S NORTH AND MID TO UPR 30S DOWNEAST. LOWS SATURDAY NIGHT WILL FALL INTO THE SINGLE DIGITS ABOVE ZERO NORTH AND LOW TO MID TEENS DOWNEAST. HIGHS ON SUNDAY WILL RANGE FROM THE MID TO UPR 20S NORTH AND LOW TO MID 30S DOWNEAST. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... QUIET WEATHER PATTERN WILL CONTINUE FOR MUCH OF THE UPCOMING WEEK. LOW PRESSURE WILL MOVE OFF THE MID ATLANTIC COAST SUNDAY EVENING AND PASS WELL TO THE SOUTH OF THE GULF OF MAINE SUNDAY NIGHT. MONDAY WILL BE A COLD AND BLUSTERY DAY AS HIGH PRESSURE SLOWLY BUILDS IN FROM THE WEST. HIGH PRESSURE WILL CONTINUE TO BUILD EAST ACROSS THE REGION ON TUESDAY...THEN MOVE EAST TUESDAY NIGHT. LOW PRESSURE WILL APPROACH FROM THE WEST TUESDAY NIGHT AND TRACK THROUGH QUEBEC PROVINCE ON WEDNESDAY. EXPECT INCREASING CLOUDS LATER TUESDAY NIGHT WITH THE CHANCE FOR SNOW SHOWERS ON WEDNESDAY. HIGH PRESSURE WILL BRIEFLY BUILD ACROSS THE REGION WEDNESDAY NIGHT BEFORE ANOTHER WEAK DISTURBANCE BRINGS ANOTHER CHANCE FOR SNOW SHOWERS ON THURSDAY. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... NEAR TERM: MVFR FOR KBGR/KBHB WILL GO TO IFR W/RAIN. ACROSS THE NORTHERN TERMINALS, VFR WILL GO TO MVFR THIS MORNING AND THEN QUICKLY TO IFR W/RASN. CONDITIONS WILL IMPROVE TO VFR FOR KBGR AND KBHB AFT 00Z W/SOME CLEARING. THE NORTHERN TERMINALS WILL SEE IFR GO MVFR LATE IN THE AFTERNOON AND THEN VFR LATER AT NIGHT. SHORT TERM: MVFR CIGS ARE POSSIBLE ACROSS THE NORTHERN TERMINALS SATURDAY...OTHERWISE MAINLY VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY. && .MARINE... NEAR TERM: DECIDED TO GO W/A SCA STARTING LATER TONIGHT THROUGH SATURDAY PER COORD W/GYX. THIS WILL MAINLY BE FOR WIND GUSTS OF 25 KT AND FOR THE OUTER ZONES AS THE INTRACOASTAL WATERS SHOULD STAY BELOW SCA THRESHOLDS. KEPT SEAS IN THE RANGE OF 2-4 FT W/ WAVE HEIGHTS GETTING CLOSE TO 5 FT. SHORT TERM: SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED SATURDAY AND INTO SATURDAY NIGHT. ANOTHER ROUND OF SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE SUNDAY NIGHT AND MONDAY AS INTENSIFYING LOW PRESSURE MOVES WELL SOUTH OF NOVA SCOTIA. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 4 PM EST SATURDAY FOR ANZ050-051. && $$ NEAR TERM...HEWITT SHORT TERM...DUDA LONG TERM...DUDA AVIATION...HEWITT MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
422 AM EST FRI FEB 17 2012 .SYNOPSIS... AN OCCLUDED FRONT WILL CROSS THE REGION TODAY. HIGH PRESSURE WILL THEN SLOWLY BUILD EAST SATURDAY INTO SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... THE CHALLENGE WILL BE SNOWFALL AND TEMPERATURES. SHORT RANGE MODEL GUIDANCE IS RUNNING TOO COLD ATTM PER THE LATEST OBS BY AT LEAST 2-4 DEGREES. THE GFS AND RUC MATCHED WELL W/THE 00Z UA SHOWING WARMER AIR MAKING ITS WAY FURTHER NORTH INTO NE AROOSTOOK COUNTY THIS AFTERNOON. RADAR WAS SHOWING LIGHT PRECIP IN THE FORM OF RAIN MOVING ACROSS THE INTERIOR SECTIONS OF DOWNEAST MAINE WHILE LIGHT SNOW IS BREAKING OUT ACROSS THE CENTRAL REGIONS. THAT WARMER AIR WILL CONTINUE TO STREAM NE LATER THIS MORNING W/SNOW MIXING W/& CHANGING OVER TO RAIN OVER THE CENTRAL AREAS AND THEN THE MIX OR EVEN CHANGEOVER TO RAIN ACROSS THE NORTHERN AREAS BY AROUND 18Z. ACROSS THE SAINT JOHN VALLEY, TEMPERATURES WILL BE RIGHT AROUND THE CRITICAL TEMPERATURES OF 32-33F W/PRECIP MAINLY IN THE FORM OF SNOW. QPF WILL BE LESS THAN .25" FOR THIS EVENT W/THE HIGHEST TOTAL OVER THE EASTERN CORRIDOR OF MAINE & MAINLY IN THE FORM OF RAIN. SNOW RATIOS ACROSS THE NORTH WILL BE IN A RANGE OF 10-11:1 AND THEN DROP BACK TO LESS THAN 10:1 BY LATE MORNING AS THE LLVLS WARM. THIS WILL CUT DOWN ON ACCUMULATIONS. STAYED W/SNOWFALL AMOUNTS OF 1-2 INCHES AND THIS WILL MAINLY BE NORTH AND WEST OF CARIBOU AND PRESQUE ISLE. THERE COULD BE A PERIOD OF MODERATE TO HEAVY SNOWFALL AS SOME MID LEVEL INSTABILITY IS SHOWN BY THE GFS TO TAKE PLACE FROM 12-18Z. HIGH TEMPERATURES TODAY WILL BE IN THE LOW TO MID 30S ACROSS THE NORTH W/UPPER 30S TO LOWER 40S ACROSS DOWNEAST AND THE COAST. FOR TONIGHT, OCCLUSION IS FCST TO SLIDE INTO NEW BRUNSWICK THIS EVENING W/STEADY PRECIP ENDING AND COOLER AIR FILTERING INTO THE REGION. AIRMASS STARTS TO DRY OUT TONIGHT MAINLY ACROSS THE CENTRAL AND DOWNEAST REGION W/SOME CLEARING. FURTHER NORTH, BRIEF CLEARING WILL GIVE WAY TO CLOUDS AS UPPER TROF MOVES ACROSS THE REGION. SOME WEAK FORCING IS THERE IN THE MID LEVELS TO TRIGGER SOME LIGHT SNOW/SNOW SHOWERS. STAYED W/20-30% POPS AND LEANED CLOSE TO THE PREVIOUS LOWS OF UPPER TEENS/LOWER 20S ACROSS THE NORTH AND WEST TO LOW TO MID 20S FOR THE CENTRAL AND DOWNEAST REGION. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... INTENSIFYING LOW PRESSURE WILL LIFT THROUGH THE CANADIAN MARITIMES ON SATURDAY WITH GUSTY WEST WINDS EXPECTED. OUTSIDE OF ANY SCATTERED SNOW SHOWERS OR FLURRIES ACROSS NORTHWEST AREAS EXPECT PARTLY SUNNY SKIES ACROSS THE NORTH AND MOSTLY SUNNY SKIES DOWNEAST. A FAST MOVING SHORT WAVE FROM THE EASTERN GREAT LAKES WILL MOVE ACROSS NEW ENGLAND LATER SATURDAY AND SATURDAY NIGHT. ANY SNOW SHOWERS WITH THIS SYSTEM WILL REMAIN TO OUR SOUTH WITH MAINLY CLEAR TO PARTLY CLOUDY SKIES EXPECTED ACROSS THE REGION. HIGH PRESSURE WILL BUILD TOWARD THE REGION ON SUNDAY WITH PARTLY TO MOSTLY SUNNY SKIES EXPECTED. HIGHS ON SATURDAY WILL RANGE THE UPR 20S TO LWR 30S NORTH AND MID TO UPR 30S DOWNEAST. LOWS SATURDAY NIGHT WILL FALL INTO THE SINGLE DIGITS ABOVE ZERO NORTH AND LOW TO MID TEENS DOWNEAST. HIGHS ON SUNDAY WILL RANGE FROM THE MID TO UPR 20S NORTH AND LOW TO MID 30S DOWNEAST. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... QUIET WEATHER PATTERN WILL CONTINUE FOR MUCH OF THE UPCOMING WEEK. LOW PRESSURE WILL MOVE OFF THE MID ATLANTIC COAST SUNDAY EVENING AND PASS WELL TO THE SOUTH OF THE GULF OF MAINE SUNDAY NIGHT. MONDAY WILL BE A COLD AND BLUSTERY DAY AS HIGH PRESSURE SLOWLY BUILDS IN FROM THE WEST. HIGH PRESSURE WILL CONTINUE TO BUILD EAST ACROSS THE REGION ON TUESDAY...THEN MOVE EAST TUESDAY NIGHT. LOW PRESSURE WILL APPROACH FROM THE WEST TUESDAY NIGHT AND TRACK THROUGH QUEBEC PROVINCE ON WEDNESDAY. EXPECT INCREASING CLOUDS LATER TUESDAY NIGHT WITH THE CHANCE FOR SNOW SHOWERS ON WEDNESDAY. HIGH PRESSURE WILL BRIEFLY BUILD ACROSS THE REGION WEDNESDAY NIGHT BEFORE ANOTHER WEAK DISTURBANCE BRINGS ANOTHER CHANCE FOR SNOW SHOWERS ON THURSDAY. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... NEAR TERM: MVFR FOR KBGR/KBHB WILL GO TO IFR W/RAIN. ACROSS THE NORTHERN TERMINALS, VFR WILL GO TO MVFR THIS MORNING AND THEN QUICKLY TO IFR W/RASN. CONDITIONS WILL IMPROVE TO VFR FOR KBGR AND KBHB AFT 00Z W/SOME CLEARING. THE NORTHERN TERMINALS WILL SEE IFR GO MVFR LATE IN THE AFTERNOON AND THEN VFR LATER AT NIGHT. SHORT TERM: MVFR CIGS ARE POSSIBLE ACROSS THE NORTHERN TERMINALS SATURDAY...OTHERWISE MAINLY VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY. && .MARINE... NEAR TERM: DECIDED TO GO W/A SCA STARTING LATER TONIGHT THROUGH SATURDAY PER COORD W/GYX. THIS WILL MAINLY BE FOR WIND GUSTS OF 25 KT AND FOR THE OUTER ZONES AS THE INTRACOASTAL WATERS SHOULD STAY BELOW SCA THRESHOLDS. KEPT SEAS IN THE RANGE OF 2-4 FT W/ WAVE HEIGHTS GETTING CLOSE TO 5 FT. SHORT TERM: SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED SATURDAY AND INTO SATURDAY NIGHT. ANOTHER ROUND OF SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE SUNDAY NIGHT AND MONDAY AS INTENSIFYING LOW PRESSURE MOVES WELL SOUTH OF NOVA SCOTIA. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 4 PM EST SATURDAY FOR ANZ050-051. && $$ NEAR TERM...HEWITT SHORT TERM...DUDA LONG TERM...DUDA AVIATION...HEWITT MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
642 PM EST SAT FEB 18 2012 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 342 PM EST SAT FEB 18 2012 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER THE UPR GRT LKS BTWN TROF CENTERED OVER QUEBEC AND A RDG ACRS WCNTRL CAN. SHRTWV EMBEDDED WITHIN THIS FLOW IS OVER LOWER MI AND DIGGING SEWD...LEAVING THE CWA UNDER VIGOROUS DNVA/UPR CNVGC/00Z-12Z H3 RISES AOA 100M IN ITS WAKE. ASSOCIATED SFC HI PRE RDG EXTENDS FM NW ONTARIO INTO MN. DESPITE THE VIGOROUS SUBSIDENCE ASSOCIATED WITH THESE DYNAMICS...PLENTY OF LO CLDS LINGER NOT ONLY OVER UPR MI IN THE CHILLY LLVL NW FLOW E OF THE INCOMING RDG AXIS BUT ALSO INTO NRN MN RIGHT UNDER THE RDG AXIS. IN FACT...THE 12Z INL/YPL RAOBS DEPICT A STRONG SUBSIDENCE INVRN. HOWEVER SINCE THE INVRN BASE IS SURPRISINGLY HI H85-875...THERE IS AMPLE DEPTH FOR LLVL MIXING WITH INVERTED V SUB-INVRN LYR. SINCE H85 TEMPS ARE STILL ARND -15C IN THE LLVL THERMAL TROF TRAILING THE DEPARTING SHRTWV...LES PERSISTS MAINLY IN THE NW SN BELTS. BUT THE INTENSITY OF THIS ACTIVITY IS DIMINISHING WITH FAIRLY HI SFC DEWPT DEPRESSIONS AND THE FLOW TENDING TOWARD MORE ACYC UNDER THE NEGATIVE DYNAMICS. FARTHER UPSTREAM...THERE IS A SHRTWV NEAR LK WINNIPEG MOVING ESEWD. BUT THE AIRMASS IS SO DRY IN THIS AREA NOTHING BUT HI CLDS MARK THE PRESENCE OF THIS FEATURE. MAIN FCST CONCERNS THRU SUN ARE CLD TRENDS TNGT/IMPACT ON TEMPS. TNGT...AS HI PRES BUILDS SLOWLY ACRS WI/UPR MI TNGT UNDER CONFLUENT WNW FLOW ALF AND THE FLOW BACKS MORE TO THE W...EXPECT LINGERING LES TO SHIFT INTO AREAS FAVORED BY THAT FLOW AND DIMINISH. WITH THE BACKING FLOW...SUSPECT THE BULK OF THE LO CLD IN NRN MN WILL DRIFT TO THE N OF UPR MI AS SHOWN BY THE 12Z LOCAL WRF-ARW MODEL. BUT THESE CLDS MAY BE MORE PERSISTENT OVER THE KEWEENAW WITH FAVORABLE UPSLOPE WIND COMPONENT DOWN THE LENGTH OF WRN LK SUP AND E OF MUNISING WITH A LATER BACKING OF THE FLOW. EVEN THOUGH SOME OF THE HI CLDS ASSOCIATED WITH THE DISTURBANCE NEAR LK WINNIPEG MAY DRIFT OVER THE CWA LATER TNGT AS THIS SHRTWV MOVES INTO NRN MN TOWARD 12Z...LGT WINDS/PWAT IN THE 0.15-0.20 INCH RANGE SUPPORT GOING FCST MIN TEMPS TOWARD THE LO END OF GUIDANCE OVER AT LEAST THE INTERIOR W HALF. SUN...AS THE SFC HI PRES RDG DRIFTS INTO LOWER MI...THE LLVL FLOW OVER UPR MI WL SHIFT TO THE SW...SO ANY LINGERING LK CLDS WL PUSH OUT INTO LK SUP. WITH A GOOD DEAL OF STRONGER LATE FEB SUNSHINE TO HEAT THIS DRY AIRMASS AND H85 TEMPS PROGGED TO REACH -5C TO -7C BY 00Z MON...EXPECT A HEALTHY DIURNAL TEMP RECOVERY TO PUSH MAX TEMPS WELL INTO THE 30S AT MOST PLACES. AREAS OVER THE E CLOSER TO THE DEPARTING H85 THERMAL TROF AND UNDER A SW FLOW OFF THE CHILLY WATERS OF LK MI WL BE COLDEST. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 342 PM EST SAT FEB 18 2012 SHORTWAVE RIDGE AND SFC HIGH PRESSURE RESULTS IN BENIGN WEATHER SUNDAY NIGHT INTO MONDAY. GOOD AGREEMENT THAT SFC RIDGE AXIS WILL RUN FM SOUTHERN WI THROUGH NORTHERN LOWER MICHIGAN AND INTO SOUTHWEST QUEBEC BY DAYBREAK MONDAY. EXPECT LOWEST TEMPS ON SUNDAY NIGHT OVER INLAND SOUTHERN AND EASTERN CWA CLOSER TO THE RIDGE AND LIGHTER WINDS. BIAS CORRECTED GFS MOS LOOKED BEST...BUT DID SOME ADDITIONAL TWEAK DOWN OF TEMPS OVR INLAND EAST. ATTN ON MONDAY TURNS TO PAIR OF SHORTWAVE TROUGHS THAT WILL BE PUSHING FM THE ROCKIES EAST INTO THE CNTRL AND NORTHERN PLAINS. GFS/ECMWF/CANADIAN INDICATE TWO DISTINCT TROUGHS IN THE PV FIELDS AND THIS STAYS THE CASE RIGHT THROUGH TUESDAY AS THE TROUGHS MOVE ACROSS UPR LAKES. MAIN ISSUE ON MONDAY IS INCREASING MID CLOUDS OUT AHEAD OF UPR TROUGHS. DESPITE CHILLY START...SHOULD BE ANOTHER WARM AFTN AS MIXING TO 925MB-900MB SUPPORTS HIGHS WELL INTO THE 30S. EXPECT NO PRECIP INTO WESTERN CWA BY 00Z TUE. NAM IS SIGNIFICANT OUTLIER BY LIFTING WELL DEFINED H85 CLOSED LOW INTO NORTHERN MN/QPF INTO FAR WESTERN UPR MI BY LATE TUESDAY AFTN. ALL OTHER GUIDANCE HAS MORE OF AN ELONGATED TROUGH FM NEB INTO NW MN AND CONTINUE TO TREND SLOWER IN ARRIVAL OF QPF OVR CWA UNTIL LATER MONDAY NIGHT. HAVE DISCOUNTED THE NAM AND TRENDED TOWARD OTHER MODELS FOR ARRIVAL OF PRECIPITATION. INTO TUESDAY...MAIN DIFFERENCE IS THAT GFS IS MORE PHASED WITH H85 TROUGHS AND HAS MORE MOISTURE ADVECTION INTO THE UPR LAKES. EVEN THE GFS SHOWS THE PRIMARY JET STREAM REMAINING ACROSS THE SOUTHERN TIER. ECMWF AND CANADIAN OFFER MORE TONED DOWN GFS IDEA BUT THEY ARE SHOWING MORE PHASING OF H85 TROUGHS THAN THEY DID EARLIER. RESULT IS MAIN MOISTURE STREAM/HIGHER PWATS STAYING TIED INTO SOUTHERN STREAM SHORTWAVE TRACKING ACROSS OHIO VALLEY INTO CNTRL GREAT LAKES WHILE UPR LAKES/UPR MICHIGAN IS WITHIN REMNANTS OF DEEPER MOISTURE BEING ADVECTED INTO THE NORTHERN STREAM SYSTEM. LIMITED LARGE SCALE PHASING ALLOWS WARMER AIR TO REMAIN TO SOUTH SO SNOW WILL BE MAIN PTYPE. ONLY EXCEPTION IS ALONG IMMEDIATE LK MICHIGAN SHORE WHERE A MIX OF RAIN/SNOW WAS MENTIONED WITH ONSHORE WINDS. BASED ON MAX TEMPS INTO MID 30S CONSIDERED ADDING RAIN MENTION ELSEWHERE...BUT WBZERO HEIGHTS LESS THAN 500AGL WOULD LEAD TO ONLY BRIEF MIXING WITH RAIN BEFORE SNOW TAKES OVER AS MAIN PYTPE. INCREASED POPS INTO THE LIKELY RANGE FOR TUESDAY...ESPECIALLY FIRST PART OF DAY ON TUESDAY OVER WEST AS THAT IS WHEN THE TWO MOISTURE STREAMS WITH THE SHORTWAVES ARE IN GREATEST PROXIMITY. HOWEVER...BASED ON THE GENERAL DOWNWARD TREND TO MOISTURE/LIFT AS TUESDAY GOES ON...IN ADDITION TO FAIRLY WARM BLYR TEMPS IN THE LOWER-MID 30S...PROBABLY WILL NOT BE MUCH FOR SNOW ACCUMS OVER UPR MI FOR MOST OF THE DAYLIGHT HOURS ON TUESDAY. POSSIBLE EXCEPTION WOULD BE IN THE FAR WEST DURING THE MORNING WHERE A FEW INCHES OF SNOW COULD OCCUR VCNTY OF KIWD. BASE OF NORTHERN STREAM TROUGH SETTLES CLOSE BY ON TUESDAY NIGHT WHILE THERE IS STILL LINGERING H85-H7 MOISTURE IN WAKE OF SYSTEM THAT MOVES THROUGH ON TUESDAY. GIVEN THE SETUP...CANNOT RULE OUT SMALL SHORTWAVES ROUNDING BASE OF TROUGH THAT DO NOT SHOW UP IN GUIDANCE RIGHT NOW. CARRIED SMALL CHANCE POPS FOR LGT SNOW SHOWERS/FLURRIES... ESPECIALLY OVER KEWEENAW WHERE WEST WINDS PROVIDE A BIT MORE MOISTENING OFF LAKE SUPERIOR. IN THE EXTENDED...SFC-H85 LOW IS FCST TO BE NORTH OF LK SUPERIOR ON WEDNESDAY. 00Z ECMWF MORE AMPLIFIED WITH SMALLER H85 LOW SLIDING ACROSS IN WESTERLY FLOW WHICH WOULD LEAD TO SWATH OF SYNOPTIC SNOW OVR PORTIONS OF THE CWA ON WEDNESDAY. ECMWF IDEA SEEMS LIKE LOW RISK AT THIS POINT AS PREVIOUS RUNS DID NOT HAVE THIS AND OTHER MEDIUM RANGE MODELS DO NOT SHOW IT AS WELL. INSTEAD WILL GO WITH IDEA THAT MAINLY QUIET CONDITIONS WILL BE AROUND ON WEDNESDAY IN WAKE OF TUESDAY SYSTEM. UPR TROUGH EVENTUALLY SLIDES THROUGH UPR LAKES LATER WEDNESDAY NIGHT INTO THURSDAY...USHERING IN COLDER AIR TO END THE WEEK. CYCLONIC FLOW WITHIN THE SFC-H5 TROUGHINESS ALLOWS DEEPER MOISTURE TO HANG AROUND THURSDAY INTO THURSDAY NIGHT. GIVEN COLD AIR ADVECTION AND THE MOISTURE...PROBABLY WILL SEE ACCUMULATING SNOWS FOR AREAS NEAR LK SUPERIOR FAVORED BY NW WINDS. DRYING FCST TO SPREAD IN FM NW ON FRIDAY AS UPR LOW CENTER SLIDES EAST. DOES COOL OFF SLIGHTLY COMPARED TO THURSDAY THOUGH...SO WOULD EXPECT LK EFFECT TO CONTINUE IN NW FLOW AREAS WITH MAINLY LGT ACCUMS. SAME GOES FOR FRIDAY NIGHT INTO SATURDAY AS SFC-H85 RIDGE IS STUBBORN TO ARRIVE FM THE WEST. KIND OF A CHANGE FROM THE QUICK-MOVING PATTERN THAT HAS BEEN PRESENT OVER THE REGION FOR MOST OF THE WINTER. MAIN CHANGE TO EXTENDED WAS TO INCREASE POPS FOR LK EFFECT AREAS COMPARED TO WHAT ALLBLEND PROCEDURE GENERATED. AWAY FM THE LAKE EFFECT...EXPECT MAINLY CLOUDY CONDITIONS WITH NEAR NORMAL TEMPS FOR LATER FEBRUARY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 642 PM EST SAT FEB 18 2012 LOW-LEVELS CONTINUE TO DRY JUST AHEAD OF APPROACHING SFC HIGH PRES RIDGE. AS THE RIDGE MOVES ACROSS THE UPPER GREAT LAKES...CLR SKIES/VFR CONDITIONS WILL BE THE RULE AT KIWD/KSAW THRU THIS FCST PERIOD. WITH A WESTERLY UPSLOPE WIND/CONTINUED OVERWATER TRAJECTORY...MVFR CIGS MAY TEND TO LINGER FOR MUCH OF THE NIGHT AT KCMX. HOWEVER...GIVEN SATELLITE TRENDS OVER THE LAST SEVERAL HRS... CLOUDS MAY SCATTER OUT THERE THIS EVENING. IT`S ALSO POSSIBLE THAT IF CLOUDS SCATTER OUT FOR A WHILE THIS EVENING...THEY MAY REDEVELOP AS NOCTURNAL COOLING AIDS LAKE EFFECT PROCESSES AND THUS MORE CLOUD FORMATION. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 342 PM EST SAT FEB 18 2012 WITH AN UNSEASONABLY WEAK PRES GRADIENT FORECAST TO DOMINATE THE UPPER GREAT LAKES THIS COMING WEEK...EXPECT WINDS NO HIGHER THAN 25 KTS THIS FORECAST PERIOD. NO GALES ARE LIKELY ANYTIME SOON. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE. LAKE MICHIGAN...NONE. && $$ SHORT TERM...KC LONG TERM...JLA AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
352 PM EST FRI FEB 17 2012 .SYNOPSIS... ISSUED AT 238 PM EST FRI FEB 17 2012 AN AREA OF LOW PRESSURE WILL TRACK EASTWARD THROUGH LOWER MICHIGAN TONIGHT PRODUCING SOME SNOWFALL. AN AREA OF HIGH PRESSURE WILL ARRIVE FOR SATURDAY NIGHT. THIS FAIR WEATHER SYSTEM WILL KEEP THE AREA DRY GOING INTO EARLY NEXT WEEK. A SLOW MOVING COLD FRONT WILL ARRIVE FOR THE MIDDLE PART OF NEXT WEEK WITH SOME RAIN OR SNOW. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 238 PM EST FRI FEB 17 2012 RADAR SHOWS A DEVELOPING AREA OF SNOW FROM NEAR GRAND RAPIDS WEST THROUGH THE MIDDLE PART OF LAKE MI. SOME INSTABILITY WAS PRESENT MAINLY FROM 850 MB TO 700 MB. THE BEST LIFT AND MOISTURE IN THE DGZ TRACKS FROM NEAR MUSKEGON TO HOLLAND AT 21Z TO CADILLAC AND MT PLEASANT BY 03Z. DEEP DRYING ARRIVES IN MUSKEGON BY 03Z...WHICH SHOULD SHUT DOWN THE HIGH RISK FOR MEASURABLE PRECIPITATION. THE HRRR RUC DOES SHOW A SUDDEN DEVELOPMENT OF SNOW IN THE 23Z TO 01Z TIMEFRAME JUST WEST OF HOLLAND AND SOUTH HAVEN WHICH TRACKS EAST INTO SOUTHWEST LOWER MI...WHICH WOULD PROLONG THE RISK FOR ACCUMULATING SNOW BEYOND 03Z. COLDER SURFACES COULD SEE AN INCH WITH LOCALLY HIGHER AMOUNTS WHERE ANY BAND PERSISTS. MUCH OF THAT SNOW COULD FALL IN AN HOURS TIME EARLY THIS EVENING. WRAP AROUND MOISTURE ON THE BACKSIDE OF THE DEPARTING LOW COULD LEAD TO A RETURN OF SOME SNOW FOR LATE TONIGHT INTO SATURDAY MORNING. AS A RESULT I WILL KEEP THE HIGHER POPS GOING TONIGHT...MAINLY FOR THE FIRST HALF OF THE NIGHT. WILL KEEP THE MENTION OF SNOW GOING INTO SATURDAY. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 238 PM EST FRI FEB 17 2012 (SUNDAY THROUGH FRIDAY) AS A STORM MOVES ALONG THE GULF COAST...HIGH PRESSURE WILL HOVER OVER THE GREAT LAKES SUNDAY AND MONDAY. AFTER MONDAY A CLIPPER AND A WAVE MOVING EAST FROM THE ROCKIES ARE PROGD TO PHASE NEAR THE GREAT LAKES TUESDAY. THE RESULT WILL BE A PERIOD OF SNOW TUESDAY NORTH OF I-96 AND GENERALLY RAIN SOUTH OF THERE. TWO MORE CLIPPERS...ONE ON WEDNESDAY AND ANOTHER THURSDAY NIGHT WILL RESULT IN PCPN FROM WED INTO FRIDAY. THE WEDNESDAY CLIPPER WILL DRAW A BIT MORE WARM AIR NORTHWARD INTO THE REGION WHICH WILL RESULT IN SOME MORE LIGHT RAIN OVER THE SRN HALF OF THE CWA WEDNESDAY BEFORE IT MOVES THROUGH. AS COLDER AIR FLOWS IN BEHIND IT...WE/LL HAVE A BETTER CHANCE AT SOME LIGHT SNOW BY THE TIME THE THURSDAY NIGHT CLIPPER ARRIVES. FROM THURSDAY INTO FRIDAY....THE LIGHT PCPN THAT FALLS WILL BE IN THE FORM OF SNOW. && .AVIATION...(FOR THE 21Z TAFS THROUGH 21Z SATURDAY AFTERNOON) ISSUED AT 238 PM EST FRI FEB 17 2012 SNOW SHOWERS WILL MOVE IN QUICKER THAN FORECASTED AND TAFS HAVE BEEN UPDATED TO ACCOUNT FOR THIS. ADDED IFR TO THE FORECAST FOR KGRR AND KLAN AS WELL. UPSTREAM CONDITIONS HAVE BRIEFLY GONE DOWN TO IFR AT MULTIPLE SITES. THE DURATION OF ANY IFR WILL LIKELY BE LIMITED...BUT A RISK WILL EXIST INTO THE EVENING FOR KGRR AND KMKG. LOWER CLOUDS WILL LIKELY LINGER INTO SAT AM WITH THE PASSAGE OF THE LOW PRESSURE SYSTEM. && .MARINE... ISSUED AT 238 PM EST FRI FEB 17 2012 SMALL CRAFT ADVISORY ISSUED FOR INCREASING WINDS AND WAVES TONIGHT. && .HYDROLOGY... ISSUED AT 330 AM EST FRI FEB 17 2012 RELATIVELY QUIET WITH THE HYDRO SECTION FOR THIS TIME OF THE YEAR. NO SIGNIFICANT RUNOFF FORECASTED THROUGH MONDAY. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY LATE TONIGHT THROUGH SATURDAY NIGHT. && $$ SYNOPSIS...MJS SHORT TERM...MJS LONG TERM....93 AVIATION...MJS MARINE...MJS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
100 PM EST FRI FEB 17 2012 .UPDATE... ISSUED AT 1245 PM EST FRI FEB 17 2012 SOUTHWARD EXTENSION OF THE SNOW IN SRN WI...SHOULD CLIP PARTS OF MY SOUTHERN COUNTIES LATER THIS AFTERNOON/EVENING AS ADVERTISED BY THE HRRR RUC. POPS HAVE BEEN INCREASED TO ACCOUNT FOR THIS THIS AFTERNOON. UPDATE ISSUED AT 1052 AM EST FRI FEB 17 2012 INCOMING MODEL DATA IS SHOWING SOME INSTABILITY AS THE AREA OF SNOW PULLS THROUGH LOWER MI LATER THIS AFTERNOON INTO THIS EVENING. UPSTREAM SAT IMAGERY SHOWS A CONVECTIVE APPEARANCE TO THE CLOUDS AND OBS HAVE INDICATED CONVECTIVE BURSTS. THUS I TOOK OUT THE LIGHT WORDING AND ALSO FEATURED MORE SNOW FOR THE AFTERNOON. HWO WAS UPDATED TO INDICATE POTENTIAL IMPACTS. BY 21Z SNOW COULD REACH HIGHWAY 131 GRR TO CAD. ISSUED AT 928 AM EST FRI FEB 17 2012 ADDED SOME SNOW TO THE LATE AFTERNOON FORECAST AROUND LUDINGTON. THE WEAK WAVE OF LOW PRESSURE MOVING IN FROM THE WEST WILL ARRIVE ACROSS MY NORTHWEST COUNTIES PRIOR TO 00Z. FAVORABLE MOISTURE IN THE DGZ COMBINED WITH STRONGER OMEGA VALUES SUPPORTS THIS ALONG WITH BUMPING UP POPS TO CATEGORICAL FOR THE REGION NORTH OF A HART TO MT PLEASANT LINE. ALONG AND SOUTH OF INTERSTATE 96 WE MAY HAVE TROUBLE MEASURING. BY 03Z THE MAIN AREA OF PRECIP SHOULD BE MOVING EAST OF LUDINGTON AS THE DGZ WILL BE DRYING OUT. SOUNDINGS AT 21Z DO HAVE A SHALLOW MELTING LAYER...BUT BY 00Z THEY ARE SEVERAL DEGREES BELOW FREEZING. SO WILL KEEP THE PRECIP TYPE AS SNOW. && .SHORT TERM...(TODAY THROUGH SATURDAY AFTERNOON) ISSUED AT 330 AM EST FRI FEB 17 2012 HIGH PRESSURE TO BRING FAIR WX TODAY WITH PARTLY CLOUDY SKIES AND SEASONABLY MILD MAX TEMPS REACHING THE UPPER 30S TO LOWER 40S. WEAK LOW PRESSURE MOVING ESE ACROSS LWR MI TONIGHT WILL BRING LIGHT SNOW. THERE IS A NARROW WINDOW OF DEEPER MOISTURE ALONG WITH DECENT OMEGAS BY EARLY TO MID EVENING AND WE WILL GO WITH LIKELY POPS FOR MUCH OF OUR FCST AREA FOR LIGHT SNOW THIS EVE. THE BEST CHC FOR LIGHT SNOW SHOULD COME NEAR TO NORTH OF I-96. WILL GO WITH CHC POPS FOR OUR FAR SOUTHERN COUNTIES. ACCUMULATIONS TONIGHT SHOULD BE RATHER LIGHT... GENERALLY AROUND AN INCH OR LESS... TO PERHAPS LOCALLY TWO INCHES IN A FEW SPOTS NORTH OF I-96. COLDER AIR ADVECTS IN SATURDAY WITH H8 TEMPS FALLING TO -11 TO -14 C BY 00Z SUN. THIS IN CONJUNCTION WITH SOME LINGERING LOW LEVEL MOISTURE SHOULD BRING A FEW LIGHT SNOW SHOWERS AND FLURRIES. ANY ACCUMULATIONS SATURDAY SHOULD BE VERY LIGHT (TRACE AMOUNTS TO LESS THAN AN INCH). .LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY) ISSUED AT 330 AM EST FRI FEB 17 2012 FROM SATURDAY NIGHT INTO MONDAY NIGHT THE WEATHER SHOULD BE RATHER TRANQUIL AND FOR THE MOST PART ON THE WARM SIDE OF NORMAL. THE REST OF THE LONG TERM FORECAST PERIOD LOOKS UNSETTLED WITH PERIODS OF LIGHT RAIN AND LIGHT SNOW. EVEN SO...TOTAL QPF FOR THIS ENTIRE WEEK SHOULD BE LESS THAN A HALF INCH IN MOST AREAS. THE 180 TO 200 KNOT JET STREAK COMING OFF ASIA (CROSSES JAPAN DURING THE DAY TIME HOURS OF TODAY) WILL BE OUR WEATHER CHANGER IN THE LONG TERM. AS THAT JET STREAK REACHES THE DATELINE EARLY NEXT WEEK IT HELPS TO BUILD A WESTERN RIDGE WHICH IN TURN DEEPENS THE CENTRAL UNITED STATES TROUGH. A SERIES OF SHORTWAVES MOVE THROUGH THE DEVELOPING TROUGH TUESDAY THROUGH THURSDAY BUT NO BIG STORM COMES OUT... JUST A SERIES OF SHORT WAVES. BEING ON THE UPSTREAM SIDE OF THE TROUGH... WARM AIR LARGELY PREVAILS THROUGH THURSDAY WITH A SLIGHT COOLING TREND THURSDAY. IN THE THURSDAY TIME FRAME IS WHEN SOME OF THE COOLER AIR STARTS TO FILTER SO I FEATURE FALLING TEMPERATURES DURING THE AFTERNOON THURSDAY AND CHANGE THE RAIN TO SNOW DURING THE DAY THURSDAY. I HAVE ABOVE AVERAGE CONFIDENCE IN THE OVERALL IDEA BEHIND THE FORECAST BUT SINCE WE ARE WATCHING WEAK SHORTWAVES TRAVEL ALONG IN THE LARGE SCALE FLOW... THE DETAILS OF WHEN AND WHERE THE RAINS/SNOWS WILL BE TUE THROUGH THURSDAY ARE DUBIOUS AT BEST. IN THE PERIOD FROM SATURDAY NIGHT THROUGH MONDAY NIGHT SHORTWAVE RIDGING PREVAILS. THAT WELL LEAD TO LIMITED CLOUD COVER AND UNSEASONABLY MILD TEMPERATURE (REMEMBER THE POLAR JET IS STILL LOCKING UP THE TRULY COLD AIR NORTH OF 55 N). && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1245 PM EST FRI FEB 17 2012 SNOW SHOWERS WILL MOVE IN QUICKER THAN FORECASTED AND TAFS HAVE BEEN UPDATED TO ACCOUNT FOR THIS. ADDED IFR TO THE FORECAST FOR KGRR AND KLAN AS WELL. UPSTREAM CONDITIONS HAVE BRIEFLY GONE DOWN TO IFR AT MULTIPLE SITES. THE DURATION OF ANY IFR WILL LIKELY BE LIMITED...BUT A RISK WILL EXIST INTO THE EVENING FOR KGRR AND KMKG. LOWER CLOUDS WILL LIKELY LINGER INTO SAT AM WITH THE PASSAGE OF THE LOW PRESSURE SYSTEM. && .MARINE... ISSUED AT 1245 PM EST FRI FEB 17 2012 THE SMALL CRAFT ADVISORY HAS EXPIRED. WINDS ARE LIKELY TO STAY UNDER 25 KNOTS THROUGH TONIGHT. WINDS WILL INCREASE SOMEWHAT ON SATURDAY AND MAY REACH SMALL CRAFT ADVISORY CRITERIA. && .HYDROLOGY... ISSUED AT 330 AM EST FRI FEB 17 2012 NO SIGNIFICANT PRECIPITATION IS FORECASTED THROUGH THE WEEKEND INTO EARLY NEXT WEEK. RIVER LEVELS ARE NOT FORECASTED TO RISE SIGNIFICANTLY THROUGH THEN. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...NONE. && $$ UPDATE...MJS SHORT TERM...LAURENS LONG TERM....WDM AVIATION...MJS MARINE...LAURENS HYDROLOGY...LAURENS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1245 PM EST FRI FEB 17 2012 .UPDATE... ISSUED AT 1144 AM EST FRI FEB 17 2012 ANOTHER UPDATE AS SNOW OVER WESTERN LK SUPERIOR IS HOLDING ITS OWN WHILE SLIDING INTO THE AREA. OTHER AREA OF LGT SNOW OVER KEWEENAW THAT IS MORE TIED TO CONVERGENCE WITH SFC TROUGH IS BEGINNING TO DROP SE INTO NCNTRL UPR MI. MOST AREAS OVR WEST HALF OF UPR MI WILL SEE LGT SNOW THROUGH REST OF AFTN. INCREASED POPS TO CATEGORICAL. A HIGH POP/LOW QPF SETUP. BASED ON UPSTREAM REPORTS AND REPORT FM KEWEENAW EARLIER...EXPECT MOST AREAS TO SEE ADDITIONAL AMOUNTS UP TO A HALF INCH OF SNOW WITH ISOLD AMOUNTS OVR 1 INCH POSSIBLE. STEADIER LGT SNOW WILL SHIFT INTO SCNTRL UPR MI...VCNTY OF IMT TO ESC TO MNM BY EARLY EVENING...THEN DEPART THAT AREA BY LATE EVENING. MAY SEE ADDITIONAL AMOUNTS UP TO 1 INCH THIS EVENING OVR SCNTRL. LK EFFECT BEGINS TO DEVELOP BY LATE EVENING/OVERNIGHT CLOSER TO LK SUPERIOR AS THE SYSTEM SNOW DEPARTS. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 437 AM EST FRI FEB 17 2012 WV SATELLITE AND RUC ANALYSIS SHOWING UPPER TROUGH CURRENTLY OVER THE NCNTRL CONUS...WITH A COUPLE SHORTWAVES EMBEDDED WITHIN THE FLOW. SHORTWAVE IN WRN MN IS AIDING A WEAK SFC LOW THAT HAS DEVELOPED ALONG A SFC TROUGH EXTENDING FROM A MUCH STRONGER LOW LOCATED OVER WRN ONTARIO. RUC ANALYSIS OF H850 TEMPS SHOWS VALUES AROUND -8.5C OVER THE ERN LK...WHICH HAS DIMINISHED MUCH OF THE LES DURING THE OVERNIGHT HOURS. FARTHER TO THE W...THERE ARE A FEW SNOW SHOWERS THAT HAVE DEVELOPED OVER THE NW CWA UNDER BROAD/WEAK H925-700 WAA. FINALLY...MORE NUMEROUS -SHSN ARE SEEN W OF A LINE FROM KELO TO KDLH ASSOCIATED WITH STRONGER H850-700 WAA/FGEN AND DEEPER MOISTURE. TODAY...THE SHORTWAVE WILL TRACK ESE THROUGH THE DAY AND KEEP THE MAIN WEAK LOW TRACKING TO THE S OF THE CWA AND THROUGH CNTRL WI. ON A BROAD SCALE...BEST H850-700 Q-VECTOR CONV...WAA...AND MOISTURE IS FOCUSED/TRACKS TO THE S OF THE CWA...FOLLOWING THE SHORTWAVE AND SFC LOW. BUT A RIBBON OF DEEPER MOISTURE JUST WNW OF KDLH AND PRODUCING THE SHOWERS WILL BE THE FIRST TO INFLUENCE THE AREA TODAY. H800-750 FGEN LINES UP WELL THE THE ONGOING -SHSN AND SHOULD START TO SLIDE INTO THE WRN CWA BETWEEN 12-15Z AND THEN INTO THE CNTRL BETWEEN 15-18Z. BUT AS IT MOVES E...THE FGEN/WAA BEGINS TO FOCUS FARTHER S/W CLOSER TO THE SFC LOW AND SHORTWAVE. THE NEXT WAVE OF H900-800 FGEN/WAA LOOKS TO PUSH OVER THE AREA HEADING INTO THE AFTN AND BRING THE BETTER CHANCE OF MORE WIDESPREAD LIGHT/MOD SNOW. 00Z NAM IS MORE PRONOUNCED ON THIS FGEN THAN THE 18Z GFS...BUT THE 00Z GFS HAS FOLLOWED SUIT AND LEADS TO HIGHER CONFIDENCE. IN ADDITION...00Z NAM/GFS BOTH SHOWING FAIRLY STRONG H850 OMEGA OVER THE SRN HALF OF THE CWA IN THE AFTN. ALL OF THIS COMBINED MADE ME FEEL CONFIDENT ON BUMPING POPS UP FROM THE GOING LOW CHANCES TO HIGH END CHANCES AND POCKETS OF LIKELY VALUES. SNOW AMNTS ARE TRICKY AS HEAVIEST ACCUMS WILL OCCUR WHERE THE BEST FGEN OCCURS AND IT APPEARS TO BE A FAIRLY NARROW CORRIDOR. SNOW RATIOS SHOULD START OUT IN THE 15/16-1 RANGE INITIALLY WITH THE HIGHER FORCING CLOSER TO THE DGZ...BUT DROP TO AROUND 13-1 DURING THE MAIN SNOW THIS AFTN...DUE TO BEST FGEN FORCING LOCATED BELOW THE DGZ AND WITH LLVL TEMPS ARE SLIGHTLY ABOVE FREEZING. WETBULB ZERO VALUES STAY BELOW 700FT SO EXPECT PCPN TO STAY AS ALL SNOW OVER THE SCNTRL CWA. OVERALL...EXPECT AREAS S OF A TWIN LAKES...TO GWINN...TO ESCANABA TO SEE A DUSTING TO AN INCH OF SNOW. BUT COULD BE SOME LOCALIZED 1.5-2IN AMOUNTS WHERE THE W-E ALIGNED BAND SETS UP. LATEST 06Z NAM RUN HAS SHIFTED THIS HEAVIER BAND SLIGHTLY FARTHER S...FROM KIMT THROUGH MENOMINEE COUNTY...SO SNOW AMNTS MAY NEED TO BE TWEAKED BASED OFF TRENDS THIS MORNING WITH LATEST RUNS. ALSO...THERE ARE SOME HINTS OF WEAK UPSLOPE/LK ENHANCED PCPN AIDING AMNTS OVER THE HIGHER TERRAIN OF MARQUETTE COUNTY...BUT WITH LIMITED COLD AIR CURRENTLY IN PLACE OVER THE LK...NOT TO CONFIDENT ON IT HELPING TOTALS TOO MUCH. TONIGHT...SHOULD SEE DIMINISHING TREND FROM W TO E DURING THE LATE AFTN AND INTO THE EVENING AS THE FGEN/MOISTURE SLIDES E AHEAD OF THE NEXT SHORTWAVE. STRONGER SHORTWAVE WILL BE DIVING S ACROSS THE UPPER GREAT LKS REGION LATE THIS EVENING AND OVERNIGHT. FOLLOWED 00Z GFS/NAM SOLN AS PREFERRED BY HPC THAT IS SLIGHTLY SLOWER AND DIVES THE WAVE ACROSS WRN/CNTRL UPPER MI. EVEN THOUGH THE SHORTWAVE LOOKS TO BE FAIRLY POTENT...MOISTURE LOOKS TO BE OF CONCERN AS MUCH OF THE DEEPER MOISTURE PULLS OUT OF THE AREA WITH THE FIRST WAVE. THIS LEAVES LIMITED CONFIDENCE IN SYNOPTIC PCPN OCCURRING. ATTENTION THEN TURNS TO LES POTENTIAL. H850 TEMPS FALLING FROM AROUND -10C AT 00Z SAT TO AROUND -14 TO -15C BY 12Z SAT WILL INCREASE THE LK INDUCED INSTABILITY. WITH LIMITED INSTABILITY/MOISTURE TO START THE EVENING...HAVE TRIMMED BACK POPS OVER THE NW U.P. SHORELINES AT THE START OF THE PERIOD. WITH THE COLDER TEMPS ARRIVING AND SHORTWAVE ENERGY PUSHING THROUGH LATE THIS EVENING AND OVERNIGHT...EXPECT LES CHANCES TO INCREASE THROUGH THE NIGHT. WINDS ARE STILL A LITTLE TRICKY SINCE HIGH RES RUNS ARE STILL HINTING AT SOME LK INDUCED TROUGHING...BUT EXPECT THE BEST CHANCES OVER THE N TO NNW WIND FAVORED LOCATIONS. WITH INVERSION HEIGHTS AROUND 5-6KFT THERE COULD BE SOME STRONGER BANDS...BUT SOME LIMITING FACTORS EXIST. FIRST...ALTHOUGH TEMPS ARE COOLING...MODELS SHOWING MUCH OF THE OMEGA OCCURRING BELOW THE DGZ...WHICH SHOULD KEEP SNOW RATIOS ON THE LOW SIDE. ONE EXCEPTION WOULD BE OVER THE KEWEENAW...WHERE THE COLDEST TEMPS ARE AND SHOULD PLACE FORCING MORE IN THE DGZ. SECOND...WITH THE SHORTWAVE MOVING THROUGH...MODELS ARE SHOWING SOME DIRECTIONAL SHEAR BETWEEN THE SFC AND H850. THUS...KEPT LES AMNTS UNDER AN INCH. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 437 AM EST FRI FEB 17 2012 UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH OVER THE GREAT LAKES REGION INTO THE NORTHERN PLAINS WITH A CLOSED LOW OVER THE GULF OF CA AND A RIDGE IS OFF THE WEST COAST. THE TROUGH OVER THE GREAT LAKES REGION WILL GET AMPLIFIED AS A SHORTWAVE DIGS SOUTHEAST INTO THE AREA TONIGHT WITH A SHORTWAVE RIDGE BUILDING INTO THE AREA SAT NIGHT INTO SUNDAY. LAKE EFFECT WILL CONTINUE TO BE GOING ON SATURDAY MORNING BEFORE THE ENVIRONMENT GETS A BIT MORE HOSTILE TO LAKE EFFECT. GFS BUFKIT SOUNDINGS SHOW AN INVERTED-V SOUNDING IN THE LOW LEVELS AT IWD...CMX AND ERY AND INVERSION HEIGHTS FALL IN THE MORNING FROM 3000-4000 FEET. DGZ ALSO FALLS IN HEIGHT AND DEEPER MOISTURE DEPARTS AS DRY AIR COMES IN. OMEGA IN THE DGZ ALSO BECOMES NEGATIVE WITH DOWNWARD MOTION AT THAT TIME SO THE LIKELY POPS IN THE MORNING IN NORTH AFFECT LAKE SUPERIOR LAKE EFFECT SNOW BELTS WILL DECREASE TO CHANCE IN THE AFTERNOON AS THE WINDS BACK MORE TOWARDS THE WEST. WINDS GO WEST TO SOUTHWEST SAT NIGHT SO ANY LINGERING LAKE EFFECT IN THE NORTH WILL PUSH OFFSHORE AND IN THE EAST WILL CONTINUE TO DIMINISH. WITH THE LIGHT SW WINDS ON LAND...TEMPERATURES WILL GET COLD AS IDEAL RADIATIONAL COOLING SETS UP WITH CLEAR SKIES AND LIGHT WINDS. WENT COLDER WITH TEMPERATURES THAN THE GOING FORECAST AND WENT WITH ADJMAV GUIDANCE WHICH LOOKED REASONABLE. SUNDAY AND SUNDAY NIGHT LOOK DRY AND THIS CARRIES INTO MONDAY AS WELL. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT TO LOWER LOW TEMPERATURES FOR SATURDAY NIGHT. IN THE EXTENDED...ECMWF SHOWS A 500 MB TROUGH THAT WILL MOVE INTO THE PLAINS ON MONDAY WITH SPLIT FLOW COMBINING TO FORM A DEEP TROUGH MOVING INTO THE UPPER GREAT LAKES LATE TUE THAT PUSHES THROUGH WITH MORE ENERGY DIGGING INTO THE GREAT LAKES WED NIGHT INTO THU. TEMPERATURES LOOK TO STAY MILD THROUGH THE PERIOD WITH TEMPERATURES ABOVE NORMAL. SYSTEM SNOW FOR MON NIGHT AND TUE. THERE IS A HINT OF SOME LAKE EFFECT FOR THE REST OF THE PERIOD WITH THE GFS SHOWING SOME COLDER AIR COMING IN. THE ECMWF DOES NOT HAVE THE COLDER AIR COMING IN SO NO LAKE EFFECT. AVERAGING THIS OUT WOULD GIVE SLIGHT CHANCE POPS AND THAT IS WHAT WILL BE FORECASTED. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON) ISSUED AT 1240 PM EST FRI FEB 17 2012 AREA OF SNOW THAT WAS OVER KEWEENAW MUCH OF THE MORNING ALONG A WEAK LOW PRESSURE TROUGH WILL SLOWLY DROP SOUTH INTO KIWD AND KSAW TERMINALS THROUGH THE AFTN. EXPECT MAINLY MVFR CONDITIONS AT THESE LOCATIONS...THOUGH VERY BRIEF LOWERING TO IFR VSBY IS POSSIBLE /THROUGH 21Z AT KIWD AND BTWN 21Z-01Z AT KSAW/. MEANWHILE... CONDITIONS WILL PROBABLY TRY TO BECOME VFR AT KCMX FOR THE REST OF THE DAY AS DRIER AIR WORKS IN FM THE NORTH. BY EARLY EVENING...EXPECT VFR CONDITIONS FOR ALL SITES AS TROUGH SETTLES SOUTH OF UPR MI. LK EFFECT SNOW SHOWERS WITH MVFR CONDITIONS SHOULD DEVELOP LATER TONIGHT INTO SATURDAY AT ALL THE TAF SITES. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 437 AM EST FRI FEB 17 2012 NO GALES ARE EXPECTED THROUGH THE PERIOD. THE STRONGEST WINDS THROUGH MID WEEK NEXT WEEK WILL OCCUR THIS MORNING AS NORTHWEST WINDS GUST TO AROUND 30 KTS ON THE PERIPHERY OF A LOW MOVING ACROSS ONTARIO. WITH WARMER TEMPERATURES AND LIGHTER WINDS...FREEZING SPRAY SHOULD NOT BE A PROBLEM EITHER. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...SRF LONG TERM...07 AVIATION...JLA MARINE...07
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1146 AM EST FRI FEB 17 2012 .UPDATE... ISSUED AT 1144 AM EST FRI FEB 17 2012 ANOTHER UPDATE AS SNOW OVER WESTERN LK SUPERIOR IS HOLDING ITS OWN WHILE SLIDING INTO THE AREA. OTHER AREA OF LGT SNOW OVER KEWEENAW THAT IS MORE TIED TO CONVERGENCE WITH SFC TROUGH IS BEGINNING TO DROP SE INTO NCNTRL UPR MI. MOST AREAS OVR WEST HALF OF UPR MI WILL SEE LGT SNOW THROUGH REST OF AFTN. INCREASED POPS TO CATEGORICAL. A HIGH POP/LOW QPF SETUP. BASED ON UPSTREAM REPORTS AND REPORT FM KEWEENAW EARLIER...EXPECT MOST AREAS TO SEE ADDITIONAL AMOUNTS UP TO A HALF INCH OF SNOW WITH ISOLD AMOUNTS OVR 1 INCH POSSIBLE. STEADIER LGT SNOW WILL SHIFT INTO SCNTRL UPR MI...VCNTY OF IMT TO ESC TO MNM BY EARLY EVENING...THEN DEPART THAT AREA BY LATE EVENING. MAY SEE ADDITIONAL AMOUNTS UP TO 1 INCH THIS EVENING OVR SCNTRL. LK EFFECT BEGINS TO DEVELOP BY LATE EVENING/OVERNIGHT CLOSER TO LK SUPERIOR AS THE SYSTEM SNOW DEPARTS. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 437 AM EST FRI FEB 17 2012 WV SATELLITE AND RUC ANALYSIS SHOWING UPPER TROUGH CURRENTLY OVER THE NCNTRL CONUS...WITH A COUPLE SHORTWAVES EMBEDDED WITHIN THE FLOW. SHORTWAVE IN WRN MN IS AIDING A WEAK SFC LOW THAT HAS DEVELOPED ALONG A SFC TROUGH EXTENDING FROM A MUCH STRONGER LOW LOCATED OVER WRN ONTARIO. RUC ANALYSIS OF H850 TEMPS SHOWS VALUES AROUND -8.5C OVER THE ERN LK...WHICH HAS DIMINISHED MUCH OF THE LES DURING THE OVERNIGHT HOURS. FARTHER TO THE W...THERE ARE A FEW SNOW SHOWERS THAT HAVE DEVELOPED OVER THE NW CWA UNDER BROAD/WEAK H925-700 WAA. FINALLY...MORE NUMEROUS -SHSN ARE SEEN W OF A LINE FROM KELO TO KDLH ASSOCIATED WITH STRONGER H850-700 WAA/FGEN AND DEEPER MOISTURE. TODAY...THE SHORTWAVE WILL TRACK ESE THROUGH THE DAY AND KEEP THE MAIN WEAK LOW TRACKING TO THE S OF THE CWA AND THROUGH CNTRL WI. ON A BROAD SCALE...BEST H850-700 Q-VECTOR CONV...WAA...AND MOISTURE IS FOCUSED/TRACKS TO THE S OF THE CWA...FOLLOWING THE SHORTWAVE AND SFC LOW. BUT A RIBBON OF DEEPER MOISTURE JUST WNW OF KDLH AND PRODUCING THE SHOWERS WILL BE THE FIRST TO INFLUENCE THE AREA TODAY. H800-750 FGEN LINES UP WELL THE THE ONGOING -SHSN AND SHOULD START TO SLIDE INTO THE WRN CWA BETWEEN 12-15Z AND THEN INTO THE CNTRL BETWEEN 15-18Z. BUT AS IT MOVES E...THE FGEN/WAA BEGINS TO FOCUS FARTHER S/W CLOSER TO THE SFC LOW AND SHORTWAVE. THE NEXT WAVE OF H900-800 FGEN/WAA LOOKS TO PUSH OVER THE AREA HEADING INTO THE AFTN AND BRING THE BETTER CHANCE OF MORE WIDESPREAD LIGHT/MOD SNOW. 00Z NAM IS MORE PRONOUNCED ON THIS FGEN THAN THE 18Z GFS...BUT THE 00Z GFS HAS FOLLOWED SUIT AND LEADS TO HIGHER CONFIDENCE. IN ADDITION...00Z NAM/GFS BOTH SHOWING FAIRLY STRONG H850 OMEGA OVER THE SRN HALF OF THE CWA IN THE AFTN. ALL OF THIS COMBINED MADE ME FEEL CONFIDENT ON BUMPING POPS UP FROM THE GOING LOW CHANCES TO HIGH END CHANCES AND POCKETS OF LIKELY VALUES. SNOW AMNTS ARE TRICKY AS HEAVIEST ACCUMS WILL OCCUR WHERE THE BEST FGEN OCCURS AND IT APPEARS TO BE A FAIRLY NARROW CORRIDOR. SNOW RATIOS SHOULD START OUT IN THE 15/16-1 RANGE INITIALLY WITH THE HIGHER FORCING CLOSER TO THE DGZ...BUT DROP TO AROUND 13-1 DURING THE MAIN SNOW THIS AFTN...DUE TO BEST FGEN FORCING LOCATED BELOW THE DGZ AND WITH LLVL TEMPS ARE SLIGHTLY ABOVE FREEZING. WETBULB ZERO VALUES STAY BELOW 700FT SO EXPECT PCPN TO STAY AS ALL SNOW OVER THE SCNTRL CWA. OVERALL...EXPECT AREAS S OF A TWIN LAKES...TO GWINN...TO ESCANABA TO SEE A DUSTING TO AN INCH OF SNOW. BUT COULD BE SOME LOCALIZED 1.5-2IN AMOUNTS WHERE THE W-E ALIGNED BAND SETS UP. LATEST 06Z NAM RUN HAS SHIFTED THIS HEAVIER BAND SLIGHTLY FARTHER S...FROM KIMT THROUGH MENOMINEE COUNTY...SO SNOW AMNTS MAY NEED TO BE TWEAKED BASED OFF TRENDS THIS MORNING WITH LATEST RUNS. ALSO...THERE ARE SOME HINTS OF WEAK UPSLOPE/LK ENHANCED PCPN AIDING AMNTS OVER THE HIGHER TERRAIN OF MARQUETTE COUNTY...BUT WITH LIMITED COLD AIR CURRENTLY IN PLACE OVER THE LK...NOT TO CONFIDENT ON IT HELPING TOTALS TOO MUCH. TONIGHT...SHOULD SEE DIMINISHING TREND FROM W TO E DURING THE LATE AFTN AND INTO THE EVENING AS THE FGEN/MOISTURE SLIDES E AHEAD OF THE NEXT SHORTWAVE. STRONGER SHORTWAVE WILL BE DIVING S ACROSS THE UPPER GREAT LKS REGION LATE THIS EVENING AND OVERNIGHT. FOLLOWED 00Z GFS/NAM SOLN AS PREFERRED BY HPC THAT IS SLIGHTLY SLOWER AND DIVES THE WAVE ACROSS WRN/CNTRL UPPER MI. EVEN THOUGH THE SHORTWAVE LOOKS TO BE FAIRLY POTENT...MOISTURE LOOKS TO BE OF CONCERN AS MUCH OF THE DEEPER MOISTURE PULLS OUT OF THE AREA WITH THE FIRST WAVE. THIS LEAVES LIMITED CONFIDENCE IN SYNOPTIC PCPN OCCURRING. ATTENTION THEN TURNS TO LES POTENTIAL. H850 TEMPS FALLING FROM AROUND -10C AT 00Z SAT TO AROUND -14 TO -15C BY 12Z SAT WILL INCREASE THE LK INDUCED INSTABILITY. WITH LIMITED INSTABILITY/MOISTURE TO START THE EVENING...HAVE TRIMMED BACK POPS OVER THE NW U.P. SHORELINES AT THE START OF THE PERIOD. WITH THE COLDER TEMPS ARRIVING AND SHORTWAVE ENERGY PUSHING THROUGH LATE THIS EVENING AND OVERNIGHT...EXPECT LES CHANCES TO INCREASE THROUGH THE NIGHT. WINDS ARE STILL A LITTLE TRICKY SINCE HIGH RES RUNS ARE STILL HINTING AT SOME LK INDUCED TROUGHING...BUT EXPECT THE BEST CHANCES OVER THE N TO NNW WIND FAVORED LOCATIONS. WITH INVERSION HEIGHTS AROUND 5-6KFT THERE COULD BE SOME STRONGER BANDS...BUT SOME LIMITING FACTORS EXIST. FIRST...ALTHOUGH TEMPS ARE COOLING...MODELS SHOWING MUCH OF THE OMEGA OCCURRING BELOW THE DGZ...WHICH SHOULD KEEP SNOW RATIOS ON THE LOW SIDE. ONE EXCEPTION WOULD BE OVER THE KEWEENAW...WHERE THE COLDEST TEMPS ARE AND SHOULD PLACE FORCING MORE IN THE DGZ. SECOND...WITH THE SHORTWAVE MOVING THROUGH...MODELS ARE SHOWING SOME DIRECTIONAL SHEAR BETWEEN THE SFC AND H850. THUS...KEPT LES AMNTS UNDER AN INCH. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 437 AM EST FRI FEB 17 2012 UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH OVER THE GREAT LAKES REGION INTO THE NORTHERN PLAINS WITH A CLOSED LOW OVER THE GULF OF CA AND A RIDGE IS OFF THE WEST COAST. THE TROUGH OVER THE GREAT LAKES REGION WILL GET AMPLIFIED AS A SHORTWAVE DIGS SOUTHEAST INTO THE AREA TONIGHT WITH A SHORTWAVE RIDGE BUILDING INTO THE AREA SAT NIGHT INTO SUNDAY. LAKE EFFECT WILL CONTINUE TO BE GOING ON SATURDAY MORNING BEFORE THE ENVIRONMENT GETS A BIT MORE HOSTILE TO LAKE EFFECT. GFS BUFKIT SOUNDINGS SHOW AN INVERTED-V SOUNDING IN THE LOW LEVELS AT IWD...CMX AND ERY AND INVERSION HEIGHTS FALL IN THE MORNING FROM 3000-4000 FEET. DGZ ALSO FALLS IN HEIGHT AND DEEPER MOISTURE DEPARTS AS DRY AIR COMES IN. OMEGA IN THE DGZ ALSO BECOMES NEGATIVE WITH DOWNWARD MOTION AT THAT TIME SO THE LIKELY POPS IN THE MORNING IN NORTH AFFECT LAKE SUPERIOR LAKE EFFECT SNOW BELTS WILL DECREASE TO CHANCE IN THE AFTERNOON AS THE WINDS BACK MORE TOWARDS THE WEST. WINDS GO WEST TO SOUTHWEST SAT NIGHT SO ANY LINGERING LAKE EFFECT IN THE NORTH WILL PUSH OFFSHORE AND IN THE EAST WILL CONTINUE TO DIMINISH. WITH THE LIGHT SW WINDS ON LAND...TEMPERATURES WILL GET COLD AS IDEAL RADIATIONAL COOLING SETS UP WITH CLEAR SKIES AND LIGHT WINDS. WENT COLDER WITH TEMPERATURES THAN THE GOING FORECAST AND WENT WITH ADJMAV GUIDANCE WHICH LOOKED REASONABLE. SUNDAY AND SUNDAY NIGHT LOOK DRY AND THIS CARRIES INTO MONDAY AS WELL. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT TO LOWER LOW TEMPERATURES FOR SATURDAY NIGHT. IN THE EXTENDED...ECMWF SHOWS A 500 MB TROUGH THAT WILL MOVE INTO THE PLAINS ON MONDAY WITH SPLIT FLOW COMBINING TO FORM A DEEP TROUGH MOVING INTO THE UPPER GREAT LAKES LATE TUE THAT PUSHES THROUGH WITH MORE ENERGY DIGGING INTO THE GREAT LAKES WED NIGHT INTO THU. TEMPERATURES LOOK TO STAY MILD THROUGH THE PERIOD WITH TEMPERATURES ABOVE NORMAL. SYSTEM SNOW FOR MON NIGHT AND TUE. THERE IS A HINT OF SOME LAKE EFFECT FOR THE REST OF THE PERIOD WITH THE GFS SHOWING SOME COLDER AIR COMING IN. THE ECMWF DOES NOT HAVE THE COLDER AIR COMING IN SO NO LAKE EFFECT. AVERAGING THIS OUT WOULD GIVE SLIGHT CHANCE POPS AND THAT IS WHAT WILL BE FORECASTED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 629 AM EST FRI FEB 17 2012 A DISTURBANCE MOVING THROUGH WI TODAY WILL SPREAD SNOW ACROSS MAINLY THE SOUTHERN 2/3RDS OF UPPER MI TODAY. BEST SHOT FOR SNOW AND LOWER VSBYS WILL BE AT KIWD...BUT STILL SOME UNCERTAINTY ON IF THE HEAVIEST SNOW WILL BE S OF THE TAF SITE. KCMX WILL LIKELY BE AT MVFR CIGS THROUGH MUCH OF THE DAY AS THE FRONT SAGS SOUTH...WHILE KIWD/KSAW WILL HAVE TO WAIT UNTIL THE -SHSN START. TRIED TO SHOW A BREAK IN LOWER CIGS BEHIND THE DISTURBANCE AND DEVELOPING LES...BUT LIGHT UPSLOPE NORTHERLY FLOW COULD LEAD TO THE SCT CLOUDS BECOMING BKN. KIWD/KCMX WILL SEE LOWEST VSBYS AFTER MIDNIGHT...AS LAKE EFFECT SNOW DEVELOPS UNDER NNW FLOW. THIS LES COULD AFFECT KSAW LATE IN THE TAF PERIOD AND ONLY MADE SLIGHT VSBY REDUCTION DUE TO UNCERTAINTY OF A FAVORABLE WIND DIRECTION. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 437 AM EST FRI FEB 17 2012 NO GALES ARE EXPECTED THROUGH THE PERIOD. THE STRONGEST WINDS THROUGH MID WEEK NEXT WEEK WILL OCCUR THIS MORNING AS NORTHWEST WINDS GUST TO AROUND 30 KTS ON THE PERIPHERY OF A LOW MOVING ACROSS ONTARIO. WITH WARMER TEMPERATURES AND LIGHTER WINDS...FREEZING SPRAY SHOULD NOT BE A PROBLEM EITHER. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...SRF LONG TERM...07 AVIATION...SRF MARINE...07
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
944 AM EST FRI FEB 17 2012 .UPDATE... ISSUED AT 943 AM EST FRI FEB 17 2012 SFC TROUGH IS SETTLING ACROSS KEWEENAW ATTM AND THAT IS HELPING TO ENHANCE THE SNOW FM THE KEWEENAW ACROSS SOUTH CENTRAL LAKE SUPERIOR. INCREASED POPS THROUGH MORNING TO ACCOUNT FOR THIS. SNOW AMOUNTS SHOULD REMAIN LESS THAN AN INCH. TWEAKED POPS FOR AFTN OVR CNTRL TO BRING IN HIGHER POPS INTO NCNTRL UPR MI. TROUGH SINKING SOUTH SHOULD ENHANCE LOW-LEVEL CONVERGENCE. MEANWHILE...LARGER SCALE UVM/LGT SNOW TIED TO H8-H7 FRONTOGENESIS SHOULD CONTINUE TO SPREAD FM WESTERN LK SUPERIOR ACROSS MUCH OF THE WEST HALF OF CWA. WOULD EXPECT THE SNOW TO BECOME ENHANCED OVR CNTRL CWA AS THIS FORCING IS SUPPLEMENTED BY THE LOWER LEVEL CONVERGENCE. IF ALL THIS COMES TOGETHER AS LATEST NAM/LOCAL WRF SHOWS...THEN MAY SEE AT LEAST LOCALIZED SNOW AMOUNTS OVER AN INCH OVER PORTIONS OF WEST HALF OF CWA. KIND OF A WETTER SNOW WITH SLR/S IN THE 10-15:1 RANGE. TEMPS/WINDS ON TRACK AND ONLY MINOR CHANGES WERE MADE. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 437 AM EST FRI FEB 17 2012 WV SATELLITE AND RUC ANALYSIS SHOWING UPPER TROUGH CURRENTLY OVER THE NCNTRL CONUS...WITH A COUPLE SHORTWAVES EMBEDDED WITHIN THE FLOW. SHORTWAVE IN WRN MN IS AIDING A WEAK SFC LOW THAT HAS DEVELOPED ALONG A SFC TROUGH EXTENDING FROM A MUCH STRONGER LOW LOCATED OVER WRN ONTARIO. RUC ANALYSIS OF H850 TEMPS SHOWS VALUES AROUND -8.5C OVER THE ERN LK...WHICH HAS DIMINISHED MUCH OF THE LES DURING THE OVERNIGHT HOURS. FARTHER TO THE W...THERE ARE A FEW SNOW SHOWERS THAT HAVE DEVELOPED OVER THE NW CWA UNDER BROAD/WEAK H925-700 WAA. FINALLY...MORE NUMEROUS -SHSN ARE SEEN W OF A LINE FROM KELO TO KDLH ASSOCIATED WITH STRONGER H850-700 WAA/FGEN AND DEEPER MOISTURE. TODAY...THE SHORTWAVE WILL TRACK ESE THROUGH THE DAY AND KEEP THE MAIN WEAK LOW TRACKING TO THE S OF THE CWA AND THROUGH CNTRL WI. ON A BROAD SCALE...BEST H850-700 Q-VECTOR CONV...WAA...AND MOISTURE IS FOCUSED/TRACKS TO THE S OF THE CWA...FOLLOWING THE SHORTWAVE AND SFC LOW. BUT A RIBBON OF DEEPER MOISTURE JUST WNW OF KDLH AND PRODUCING THE SHOWERS WILL BE THE FIRST TO INFLUENCE THE AREA TODAY. H800-750 FGEN LINES UP WELL THE THE ONGOING -SHSN AND SHOULD START TO SLIDE INTO THE WRN CWA BETWEEN 12-15Z AND THEN INTO THE CNTRL BETWEEN 15-18Z. BUT AS IT MOVES E...THE FGEN/WAA BEGINS TO FOCUS FARTHER S/W CLOSER TO THE SFC LOW AND SHORTWAVE. THE NEXT WAVE OF H900-800 FGEN/WAA LOOKS TO PUSH OVER THE AREA HEADING INTO THE AFTN AND BRING THE BETTER CHANCE OF MORE WIDESPREAD LIGHT/MOD SNOW. 00Z NAM IS MORE PRONOUNCED ON THIS FGEN THAN THE 18Z GFS...BUT THE 00Z GFS HAS FOLLOWED SUIT AND LEADS TO HIGHER CONFIDENCE. IN ADDITION...00Z NAM/GFS BOTH SHOWING FAIRLY STRONG H850 OMEGA OVER THE SRN HALF OF THE CWA IN THE AFTN. ALL OF THIS COMBINED MADE ME FEEL CONFIDENT ON BUMPING POPS UP FROM THE GOING LOW CHANCES TO HIGH END CHANCES AND POCKETS OF LIKELY VALUES. SNOW AMNTS ARE TRICKY AS HEAVIEST ACCUMS WILL OCCUR WHERE THE BEST FGEN OCCURS AND IT APPEARS TO BE A FAIRLY NARROW CORRIDOR. SNOW RATIOS SHOULD START OUT IN THE 15/16-1 RANGE INITIALLY WITH THE HIGHER FORCING CLOSER TO THE DGZ...BUT DROP TO AROUND 13-1 DURING THE MAIN SNOW THIS AFTN...DUE TO BEST FGEN FORCING LOCATED BELOW THE DGZ AND WITH LLVL TEMPS ARE SLIGHTLY ABOVE FREEZING. WETBULB ZERO VALUES STAY BELOW 700FT SO EXPECT PCPN TO STAY AS ALL SNOW OVER THE SCNTRL CWA. OVERALL...EXPECT AREAS S OF A TWIN LAKES...TO GWINN...TO ESCANABA TO SEE A DUSTING TO AN INCH OF SNOW. BUT COULD BE SOME LOCALIZED 1.5-2IN AMOUNTS WHERE THE W-E ALIGNED BAND SETS UP. LATEST 06Z NAM RUN HAS SHIFTED THIS HEAVIER BAND SLIGHTLY FARTHER S...FROM KIMT THROUGH MENOMINEE COUNTY...SO SNOW AMNTS MAY NEED TO BE TWEAKED BASED OFF TRENDS THIS MORNING WITH LATEST RUNS. ALSO...THERE ARE SOME HINTS OF WEAK UPSLOPE/LK ENHANCED PCPN AIDING AMNTS OVER THE HIGHER TERRAIN OF MARQUETTE COUNTY...BUT WITH LIMITED COLD AIR CURRENTLY IN PLACE OVER THE LK...NOT TO CONFIDENT ON IT HELPING TOTALS TOO MUCH. TONIGHT...SHOULD SEE DIMINISHING TREND FROM W TO E DURING THE LATE AFTN AND INTO THE EVENING AS THE FGEN/MOISTURE SLIDES E AHEAD OF THE NEXT SHORTWAVE. STRONGER SHORTWAVE WILL BE DIVING S ACROSS THE UPPER GREAT LKS REGION LATE THIS EVENING AND OVERNIGHT. FOLLOWED 00Z GFS/NAM SOLN AS PREFERRED BY HPC THAT IS SLIGHTLY SLOWER AND DIVES THE WAVE ACROSS WRN/CNTRL UPPER MI. EVEN THOUGH THE SHORTWAVE LOOKS TO BE FAIRLY POTENT...MOISTURE LOOKS TO BE OF CONCERN AS MUCH OF THE DEEPER MOISTURE PULLS OUT OF THE AREA WITH THE FIRST WAVE. THIS LEAVES LIMITED CONFIDENCE IN SYNOPTIC PCPN OCCURRING. ATTENTION THEN TURNS TO LES POTENTIAL. H850 TEMPS FALLING FROM AROUND -10C AT 00Z SAT TO AROUND -14 TO -15C BY 12Z SAT WILL INCREASE THE LK INDUCED INSTABILITY. WITH LIMITED INSTABILITY/MOISTURE TO START THE EVENING...HAVE TRIMMED BACK POPS OVER THE NW U.P. SHORELINES AT THE START OF THE PERIOD. WITH THE COLDER TEMPS ARRIVING AND SHORTWAVE ENERGY PUSHING THROUGH LATE THIS EVENING AND OVERNIGHT...EXPECT LES CHANCES TO INCREASE THROUGH THE NIGHT. WINDS ARE STILL A LITTLE TRICKY SINCE HIGH RES RUNS ARE STILL HINTING AT SOME LK INDUCED TROUGHING...BUT EXPECT THE BEST CHANCES OVER THE N TO NNW WIND FAVORED LOCATIONS. WITH INVERSION HEIGHTS AROUND 5-6KFT THERE COULD BE SOME STRONGER BANDS...BUT SOME LIMITING FACTORS EXIST. FIRST...ALTHOUGH TEMPS ARE COOLING...MODELS SHOWING MUCH OF THE OMEGA OCCURRING BELOW THE DGZ...WHICH SHOULD KEEP SNOW RATIOS ON THE LOW SIDE. ONE EXCEPTION WOULD BE OVER THE KEWEENAW...WHERE THE COLDEST TEMPS ARE AND SHOULD PLACE FORCING MORE IN THE DGZ. SECOND...WITH THE SHORTWAVE MOVING THROUGH...MODELS ARE SHOWING SOME DIRECTIONAL SHEAR BETWEEN THE SFC AND H850. THUS...KEPT LES AMNTS UNDER AN INCH. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 437 AM EST FRI FEB 17 2012 UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH OVER THE GREAT LAKES REGION INTO THE NORTHERN PLAINS WITH A CLOSED LOW OVER THE GULF OF CA AND A RIDGE IS OFF THE WEST COAST. THE TROUGH OVER THE GREAT LAKES REGION WILL GET AMPLIFIED AS A SHORTWAVE DIGS SOUTHEAST INTO THE AREA TONIGHT WITH A SHORTWAVE RIDGE BUILDING INTO THE AREA SAT NIGHT INTO SUNDAY. LAKE EFFECT WILL CONTINUE TO BE GOING ON SATURDAY MORNING BEFORE THE ENVIRONMENT GETS A BIT MORE HOSTILE TO LAKE EFFECT. GFS BUFKIT SOUNDINGS SHOW AN INVERTED-V SOUNDING IN THE LOW LEVELS AT IWD...CMX AND ERY AND INVERSION HEIGHTS FALL IN THE MORNING FROM 3000-4000 FEET. DGZ ALSO FALLS IN HEIGHT AND DEEPER MOISTURE DEPARTS AS DRY AIR COMES IN. OMEGA IN THE DGZ ALSO BECOMES NEGATIVE WITH DOWNWARD MOTION AT THAT TIME SO THE LIKELY POPS IN THE MORNING IN NORTH AFFECT LAKE SUPERIOR LAKE EFFECT SNOW BELTS WILL DECREASE TO CHANCE IN THE AFTERNOON AS THE WINDS BACK MORE TOWARDS THE WEST. WINDS GO WEST TO SOUTHWEST SAT NIGHT SO ANY LINGERING LAKE EFFECT IN THE NORTH WILL PUSH OFFSHORE AND IN THE EAST WILL CONTINUE TO DIMINISH. WITH THE LIGHT SW WINDS ON LAND...TEMPERATURES WILL GET COLD AS IDEAL RADIATIONAL COOLING SETS UP WITH CLEAR SKIES AND LIGHT WINDS. WENT COLDER WITH TEMPERATURES THAN THE GOING FORECAST AND WENT WITH ADJMAV GUIDANCE WHICH LOOKED REASONABLE. SUNDAY AND SUNDAY NIGHT LOOK DRY AND THIS CARRIES INTO MONDAY AS WELL. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT TO LOWER LOW TEMPERATURES FOR SATURDAY NIGHT. IN THE EXTENDED...ECMWF SHOWS A 500 MB TROUGH THAT WILL MOVE INTO THE PLAINS ON MONDAY WITH SPLIT FLOW COMBINING TO FORM A DEEP TROUGH MOVING INTO THE UPPER GREAT LAKES LATE TUE THAT PUSHES THROUGH WITH MORE ENERGY DIGGING INTO THE GREAT LAKES WED NIGHT INTO THU. TEMPERATURES LOOK TO STAY MILD THROUGH THE PERIOD WITH TEMPERATURES ABOVE NORMAL. SYSTEM SNOW FOR MON NIGHT AND TUE. THERE IS A HINT OF SOME LAKE EFFECT FOR THE REST OF THE PERIOD WITH THE GFS SHOWING SOME COLDER AIR COMING IN. THE ECMWF DOES NOT HAVE THE COLDER AIR COMING IN SO NO LAKE EFFECT. AVERAGING THIS OUT WOULD GIVE SLIGHT CHANCE POPS AND THAT IS WHAT WILL BE FORECASTED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 629 AM EST FRI FEB 17 2012 A DISTURBANCE MOVING THROUGH WI TODAY WILL SPREAD SNOW ACROSS MAINLY THE SOUTHERN 2/3RDS OF UPPER MI TODAY. BEST SHOT FOR SNOW AND LOWER VSBYS WILL BE AT KIWD...BUT STILL SOME UNCERTAINTY ON IF THE HEAVIEST SNOW WILL BE S OF THE TAF SITE. KCMX WILL LIKELY BE AT MVFR CIGS THROUGH MUCH OF THE DAY AS THE FRONT SAGS SOUTH...WHILE KIWD/KSAW WILL HAVE TO WAIT UNTIL THE -SHSN START. TRIED TO SHOW A BREAK IN LOWER CIGS BEHIND THE DISTURBANCE AND DEVELOPING LES...BUT LIGHT UPSLOPE NORTHERLY FLOW COULD LEAD TO THE SCT CLOUDS BECOMING BKN. KIWD/KCMX WILL SEE LOWEST VSBYS AFTER MIDNIGHT...AS LAKE EFFECT SNOW DEVELOPS UNDER NNW FLOW. THIS LES COULD AFFECT KSAW LATE IN THE TAF PERIOD AND ONLY MADE SLIGHT VSBY REDUCTION DUE TO UNCERTAINTY OF A FAVORABLE WIND DIRECTION. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 437 AM EST FRI FEB 17 2012 NO GALES ARE EXPECTED THROUGH THE PERIOD. THE STRONGEST WINDS THROUGH MID WEEK NEXT WEEK WILL OCCUR THIS MORNING AS NORTHWEST WINDS GUST TO AROUND 30 KTS ON THE PERIPHERY OF A LOW MOVING ACROSS ONTARIO. WITH WARMER TEMPERATURES AND LIGHTER WINDS...FREEZING SPRAY SHOULD NOT BE A PROBLEM EITHER. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...SRF LONG TERM...07 AVIATION...SRF MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
629 AM EST FRI FEB 17 2012 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 437 AM EST FRI FEB 17 2012 WV SATELLITE AND RUC ANALYSIS SHOWING UPPER TROUGH CURRENTLY OVER THE NCNTRL CONUS...WITH A COUPLE SHORTWAVES EMBEDDED WITHIN THE FLOW. SHORTWAVE IN WRN MN IS AIDING A WEAK SFC LOW THAT HAS DEVELOPED ALONG A SFC TROUGH EXTENDING FROM A MUCH STRONGER LOW LOCATED OVER WRN ONTARIO. RUC ANALYSIS OF H850 TEMPS SHOWS VALUES AROUND -8.5C OVER THE ERN LK...WHICH HAS DIMINISHED MUCH OF THE LES DURING THE OVERNIGHT HOURS. FARTHER TO THE W...THERE ARE A FEW SNOW SHOWERS THAT HAVE DEVELOPED OVER THE NW CWA UNDER BROAD/WEAK H925-700 WAA. FINALLY...MORE NUMEROUS -SHSN ARE SEEN W OF A LINE FROM KELO TO KDLH ASSOCIATED WITH STRONGER H850-700 WAA/FGEN AND DEEPER MOISTURE. TODAY...THE SHORTWAVE WILL TRACK ESE THROUGH THE DAY AND KEEP THE MAIN WEAK LOW TRACKING TO THE S OF THE CWA AND THROUGH CNTRL WI. ON A BROAD SCALE...BEST H850-700 Q-VECTOR CONV...WAA...AND MOISTURE IS FOCUSED/TRACKS TO THE S OF THE CWA...FOLLOWING THE SHORTWAVE AND SFC LOW. BUT A RIBBON OF DEEPER MOISTURE JUST WNW OF KDLH AND PRODUCING THE SHOWERS WILL BE THE FIRST TO INFLUENCE THE AREA TODAY. H800-750 FGEN LINES UP WELL THE THE ONGOING -SHSN AND SHOULD START TO SLIDE INTO THE WRN CWA BETWEEN 12-15Z AND THEN INTO THE CNTRL BETWEEN 15-18Z. BUT AS IT MOVES E...THE FGEN/WAA BEGINS TO FOCUS FARTHER S/W CLOSER TO THE SFC LOW AND SHORTWAVE. THE NEXT WAVE OF H900-800 FGEN/WAA LOOKS TO PUSH OVER THE AREA HEADING INTO THE AFTN AND BRING THE BETTER CHANCE OF MORE WIDESPREAD LIGHT/MOD SNOW. 00Z NAM IS MORE PRONOUNCED ON THIS FGEN THAN THE 18Z GFS...BUT THE 00Z GFS HAS FOLLOWED SUIT AND LEADS TO HIGHER CONFIDENCE. IN ADDITION...00Z NAM/GFS BOTH SHOWING FAIRLY STRONG H850 OMEGA OVER THE SRN HALF OF THE CWA IN THE AFTN. ALL OF THIS COMBINED MADE ME FEEL CONFIDENT ON BUMPING POPS UP FROM THE GOING LOW CHANCES TO HIGH END CHANCES AND POCKETS OF LIKELY VALUES. SNOW AMNTS ARE TRICKY AS HEAVIEST ACCUMS WILL OCCUR WHERE THE BEST FGEN OCCURS AND IT APPEARS TO BE A FAIRLY NARROW CORRIDOR. SNOW RATIOS SHOULD START OUT IN THE 15/16-1 RANGE INITIALLY WITH THE HIGHER FORCING CLOSER TO THE DGZ...BUT DROP TO AROUND 13-1 DURING THE MAIN SNOW THIS AFTN...DUE TO BEST FGEN FORCING LOCATED BELOW THE DGZ AND WITH LLVL TEMPS ARE SLIGHTLY ABOVE FREEZING. WETBULB ZERO VALUES STAY BELOW 700FT SO EXPECT PCPN TO STAY AS ALL SNOW OVER THE SCNTRL CWA. OVERALL...EXPECT AREAS S OF A TWIN LAKES...TO GWINN...TO ESCANABA TO SEE A DUSTING TO AN INCH OF SNOW. BUT COULD BE SOME LOCALIZED 1.5-2IN AMOUNTS WHERE THE W-E ALIGNED BAND SETS UP. LATEST 06Z NAM RUN HAS SHIFTED THIS HEAVIER BAND SLIGHTLY FARTHER S...FROM KIMT THROUGH MENOMINEE COUNTY...SO SNOW AMNTS MAY NEED TO BE TWEAKED BASED OFF TRENDS THIS MORNING WITH LATEST RUNS. ALSO...THERE ARE SOME HINTS OF WEAK UPSLOPE/LK ENHANCED PCPN AIDING AMNTS OVER THE HIGHER TERRAIN OF MARQUETTE COUNTY...BUT WITH LIMITED COLD AIR CURRENTLY IN PLACE OVER THE LK...NOT TO CONFIDENT ON IT HELPING TOTALS TOO MUCH. TONIGHT...SHOULD SEE DIMINISHING TREND FROM W TO E DURING THE LATE AFTN AND INTO THE EVENING AS THE FGEN/MOISTURE SLIDES E AHEAD OF THE NEXT SHORTWAVE. STRONGER SHORTWAVE WILL BE DIVING S ACROSS THE UPPER GREAT LKS REGION LATE THIS EVENING AND OVERNIGHT. FOLLOWED 00Z GFS/NAM SOLN AS PREFERRED BY HPC THAT IS SLIGHTLY SLOWER AND DIVES THE WAVE ACROSS WRN/CNTRL UPPER MI. EVEN THOUGH THE SHORTWAVE LOOKS TO BE FAIRLY POTENT...MOISTURE LOOKS TO BE OF CONCERN AS MUCH OF THE DEEPER MOISTURE PULLS OUT OF THE AREA WITH THE FIRST WAVE. THIS LEAVES LIMITED CONFIDENCE IN SYNOPTIC PCPN OCCURRING. ATTENTION THEN TURNS TO LES POTENTIAL. H850 TEMPS FALLING FROM AROUND -10C AT 00Z SAT TO AROUND -14 TO -15C BY 12Z SAT WILL INCREASE THE LK INDUCED INSTABILITY. WITH LIMITED INSTABILITY/MOISTURE TO START THE EVENING...HAVE TRIMMED BACK POPS OVER THE NW U.P. SHORELINES AT THE START OF THE PERIOD. WITH THE COLDER TEMPS ARRIVING AND SHORTWAVE ENERGY PUSHING THROUGH LATE THIS EVENING AND OVERNIGHT...EXPECT LES CHANCES TO INCREASE THROUGH THE NIGHT. WINDS ARE STILL A LITTLE TRICKY SINCE HIGH RES RUNS ARE STILL HINTING AT SOME LK INDUCED TROUGHING...BUT EXPECT THE BEST CHANCES OVER THE N TO NNW WIND FAVORED LOCATIONS. WITH INVERSION HEIGHTS AROUND 5-6KFT THERE COULD BE SOME STRONGER BANDS...BUT SOME LIMITING FACTORS EXIST. FIRST...ALTHOUGH TEMPS ARE COOLING...MODELS SHOWING MUCH OF THE OMEGA OCCURRING BELOW THE DGZ...WHICH SHOULD KEEP SNOW RATIOS ON THE LOW SIDE. ONE EXCEPTION WOULD BE OVER THE KEWEENAW...WHERE THE COLDEST TEMPS ARE AND SHOULD PLACE FORCING MORE IN THE DGZ. SECOND...WITH THE SHORTWAVE MOVING THROUGH...MODELS ARE SHOWING SOME DIRECTIONAL SHEAR BETWEEN THE SFC AND H850. THUS...KEPT LES AMNTS UNDER AN INCH. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 437 AM EST FRI FEB 17 2012 UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH OVER THE GREAT LAKES REGION INTO THE NORTHERN PLAINS WITH A CLOSED LOW OVER THE GULF OF CA AND A RIDGE IS OFF THE WEST COAST. THE TROUGH OVER THE GREAT LAKES REGION WILL GET AMPLIFIED AS A SHORTWAVE DIGS SOUTHEAST INTO THE AREA TONIGHT WITH A SHORTWAVE RIDGE BUILDING INTO THE AREA SAT NIGHT INTO SUNDAY. LAKE EFFECT WILL CONTINUE TO BE GOING ON SATURDAY MORNING BEFORE THE ENVIRONMENT GETS A BIT MORE HOSTILE TO LAKE EFFECT. GFS BUFKIT SOUNDINGS SHOW AN INVERTED-V SOUNDING IN THE LOW LEVELS AT IWD...CMX AND ERY AND INVERSION HEIGHTS FALL IN THE MORNING FROM 3000-4000 FEET. DGZ ALSO FALLS IN HEIGHT AND DEEPER MOISTURE DEPARTS AS DRY AIR COMES IN. OMEGA IN THE DGZ ALSO BECOMES NEGATIVE WITH DOWNWARD MOTION AT THAT TIME SO THE LIKELY POPS IN THE MORNING IN NORTH AFFECT LAKE SUPERIOR LAKE EFFECT SNOW BELTS WILL DECREASE TO CHANCE IN THE AFTERNOON AS THE WINDS BACK MORE TOWARDS THE WEST. WINDS GO WEST TO SOUTHWEST SAT NIGHT SO ANY LINGERING LAKE EFFECT IN THE NORTH WILL PUSH OFFSHORE AND IN THE EAST WILL CONTINUE TO DIMINISH. WITH THE LIGHT SW WINDS ON LAND...TEMPERATURES WILL GET COLD AS IDEAL RADIATIONAL COOLING SETS UP WITH CLEAR SKIES AND LIGHT WINDS. WENT COLDER WITH TEMPERATURES THAN THE GOING FORECAST AND WENT WITH ADJMAV GUIDANCE WHICH LOOKED REASONABLE. SUNDAY AND SUNDAY NIGHT LOOK DRY AND THIS CARRIES INTO MONDAY AS WELL. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT TO LOWER LOW TEMPERATURES FOR SATURDAY NIGHT. IN THE EXTENDED...ECMWF SHOWS A 500 MB TROUGH THAT WILL MOVE INTO THE PLAINS ON MONDAY WITH SPLIT FLOW COMBINING TO FORM A DEEP TROUGH MOVING INTO THE UPPER GREAT LAKES LATE TUE THAT PUSHES THROUGH WITH MORE ENERGY DIGGING INTO THE GREAT LAKES WED NIGHT INTO THU. TEMPERATURES LOOK TO STAY MILD THROUGH THE PERIOD WITH TEMPERATURES ABOVE NORMAL. SYSTEM SNOW FOR MON NIGHT AND TUE. THERE IS A HINT OF SOME LAKE EFFECT FOR THE REST OF THE PERIOD WITH THE GFS SHOWING SOME COLDER AIR COMING IN. THE ECMWF DOES NOT HAVE THE COLDER AIR COMING IN SO NO LAKE EFFECT. AVERAGING THIS OUT WOULD GIVE SLIGHT CHANCE POPS AND THAT IS WHAT WILL BE FORECASTED. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING) ISSUED AT 629 AM EST FRI FEB 17 2012 A DISTURBANCE MOVING THROUGH WI TODAY WILL SPREAD SNOW ACROSS MAINLY THE SOUTHERN 2/3RDS OF UPPER MI TODAY. BEST SHOT FOR SNOW AND LOWER VSBYS WILL BE AT KIWD...BUT STILL SOME UNCERTAINTY ON IF THE HEAVIEST SNOW WILL BE S OF THE TAF SITE. KCMX WILL LIKELY BE AT MVFR CIGS THROUGH MUCH OF THE DAY AS THE FRONT SAGS SOUTH...WHILE KIWD/KSAW WILL HAVE TO WAIT UNTIL THE -SHSN START. TRIED TO SHOW A BREAK IN LOWER CIGS BEHIND THE DISTURBANCE AND DEVELOPING LES...BUT LIGHT UPSLOPE NORTHERLY FLOW COULD LEAD TO THE SCT CLOUDS BECOMING BKN. KIWD/KCMX WILL SEE LOWEST VSBYS AFTER MIDNIGHT...AS LAKE EFFECT SNOW DEVELOPS UNDER NNW FLOW. THIS LES COULD AFFECT KSAW LATE IN THE TAF PERIOD AND ONLY MADE SLIGHT VSBY REDUCTION DUE TO UNCERTAINTY OF A FAVORABLE WIND DIRECTION. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 437 AM EST FRI FEB 17 2012 NO GALES ARE EXPECTED THROUGH THE PERIOD. THE STRONGEST WINDS THROUGH MID WEEK NEXT WEEK WILL OCCUR THIS MORNING AS NORTHWEST WINDS GUST TO AROUND 30 KTS ON THE PERIPHERY OF A LOW MOVING ACROSS ONTARIO. WITH WARMER TEMPERATURES AND LIGHTER WINDS...FREEZING SPRAY SHOULD NOT BE A PROBLEM EITHER. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...07 AVIATION...SRF MARINE...07
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
438 AM EST FRI FEB 17 2012 .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 437 AM EST FRI FEB 17 2012 WV SATELLITE AND RUC ANALYSIS SHOWING UPPER TROUGH CURRENTLY OVER THE NCNTRL CONUS...WITH A COUPLE SHORTWAVES EMBEDDED WITHIN THE FLOW. SHORTWAVE IN WRN MN IS AIDING A WEAK SFC LOW THAT HAS DEVELOPED ALONG A SFC TROUGH EXTENDING FROM A MUCH STRONGER LOW LOCATED OVER WRN ONTARIO. RUC ANALYSIS OF H850 TEMPS SHOWS VALUES AROUND -8.5C OVER THE ERN LK...WHICH HAS DIMINISHED MUCH OF THE LES DURING THE OVERNIGHT HOURS. FARTHER TO THE W...THERE ARE A FEW SNOW SHOWERS THAT HAVE DEVELOPED OVER THE NW CWA UNDER BROAD/WEAK H925-700 WAA. FINALLY...MORE NUMEROUS -SHSN ARE SEEN W OF A LINE FROM KELO TO KDLH ASSOCIATED WITH STRONGER H850-700 WAA/FGEN AND DEEPER MOISTURE. TODAY...THE SHORTWAVE WILL TRACK ESE THROUGH THE DAY AND KEEP THE MAIN WEAK LOW TRACKING TO THE S OF THE CWA AND THROUGH CNTRL WI. ON A BROAD SCALE...BEST H850-700 Q-VECTOR CONV...WAA...AND MOISTURE IS FOCUSED/TRACKS TO THE S OF THE CWA...FOLLOWING THE SHORTWAVE AND SFC LOW. BUT A RIBBON OF DEEPER MOISTURE JUST WNW OF KDLH AND PRODUCING THE SHOWERS WILL BE THE FIRST TO INFLUENCE THE AREA TODAY. H800-750 FGEN LINES UP WELL THE THE ONGOING -SHSN AND SHOULD START TO SLIDE INTO THE WRN CWA BETWEEN 12-15Z AND THEN INTO THE CNTRL BETWEEN 15-18Z. BUT AS IT MOVES E...THE FGEN/WAA BEGINS TO FOCUS FARTHER S/W CLOSER TO THE SFC LOW AND SHORTWAVE. THE NEXT WAVE OF H900-800 FGEN/WAA LOOKS TO PUSH OVER THE AREA HEADING INTO THE AFTN AND BRING THE BETTER CHANCE OF MORE WIDESPREAD LIGHT/MOD SNOW. 00Z NAM IS MORE PRONOUNCED ON THIS FGEN THAN THE 18Z GFS...BUT THE 00Z GFS HAS FOLLOWED SUIT AND LEADS TO HIGHER CONFIDENCE. IN ADDITION...00Z NAM/GFS BOTH SHOWING FAIRLY STRONG H850 OMEGA OVER THE SRN HALF OF THE CWA IN THE AFTN. ALL OF THIS COMBINED MADE ME FEEL CONFIDENT ON BUMPING POPS UP FROM THE GOING LOW CHANCES TO HIGH END CHANCES AND POCKETS OF LIKELY VALUES. SNOW AMNTS ARE TRICKY AS HEAVIEST ACCUMS WILL OCCUR WHERE THE BEST FGEN OCCURS AND IT APPEARS TO BE A FAIRLY NARROW CORRIDOR. SNOW RATIOS SHOULD START OUT IN THE 15/16-1 RANGE INITIALLY WITH THE HIGHER FORCING CLOSER TO THE DGZ...BUT DROP TO AROUND 13-1 DURING THE MAIN SNOW THIS AFTN...DUE TO BEST FGEN FORCING LOCATED BELOW THE DGZ AND WITH LLVL TEMPS ARE SLIGHTLY ABOVE FREEZING. WETBULB ZERO VALUES STAY BELOW 700FT SO EXPECT PCPN TO STAY AS ALL SNOW OVER THE SCNTRL CWA. OVERALL...EXPECT AREAS S OF A TWIN LAKES...TO GWINN...TO ESCANABA TO SEE A DUSTING TO AN INCH OF SNOW. BUT COULD BE SOME LOCALIZED 1.5-2IN AMOUNTS WHERE THE W-E ALIGNED BAND SETS UP. LATEST 06Z NAM RUN HAS SHIFTED THIS HEAVIER BAND SLIGHTLY FARTHER S...FROM KIMT THROUGH MENOMINEE COUNTY...SO SNOW AMNTS MAY NEED TO BE TWEAKED BASED OFF TRENDS THIS MORNING WITH LATEST RUNS. ALSO...THERE ARE SOME HINTS OF WEAK UPSLOPE/LK ENHANCED PCPN AIDING AMNTS OVER THE HIGHER TERRAIN OF MARQUETTE COUNTY...BUT WITH LIMITED COLD AIR CURRENTLY IN PLACE OVER THE LK...NOT TO CONFIDENT ON IT HELPING TOTALS TOO MUCH. TONIGHT...SHOULD SEE DIMINISHING TREND FROM W TO E DURING THE LATE AFTN AND INTO THE EVENING AS THE FGEN/MOISTURE SLIDES E AHEAD OF THE NEXT SHORTWAVE. STRONGER SHORTWAVE WILL BE DIVING S ACROSS THE UPPER GREAT LKS REGION LATE THIS EVENING AND OVERNIGHT. FOLLOWED 00Z GFS/NAM SOLN AS PREFERRED BY HPC THAT IS SLIGHTLY SLOWER AND DIVES THE WAVE ACROSS WRN/CNTRL UPPER MI. EVEN THOUGH THE SHORTWAVE LOOKS TO BE FAIRLY POTENT...MOISTURE LOOKS TO BE OF CONCERN AS MUCH OF THE DEEPER MOISTURE PULLS OUT OF THE AREA WITH THE FIRST WAVE. THIS LEAVES LIMITED CONFIDENCE IN SYNOPTIC PCPN OCCURRING. ATTENTION THEN TURNS TO LES POTENTIAL. H850 TEMPS FALLING FROM AROUND -10C AT 00Z SAT TO AROUND -14 TO -15C BY 12Z SAT WILL INCREASE THE LK INDUCED INSTABILITY. WITH LIMITED INSTABILITY/MOISTURE TO START THE EVENING...HAVE TRIMMED BACK POPS OVER THE NW U.P. SHORELINES AT THE START OF THE PERIOD. WITH THE COLDER TEMPS ARRIVING AND SHORTWAVE ENERGY PUSHING THROUGH LATE THIS EVENING AND OVERNIGHT...EXPECT LES CHANCES TO INCREASE THROUGH THE NIGHT. WINDS ARE STILL A LITTLE TRICKY SINCE HIGH RES RUNS ARE STILL HINTING AT SOME LK INDUCED TROUGHING...BUT EXPECT THE BEST CHANCES OVER THE N TO NNW WIND FAVORED LOCATIONS. WITH INVERSION HEIGHTS AROUND 5-6KFT THERE COULD BE SOME STRONGER BANDS...BUT SOME LIMITING FACTORS EXIST. FIRST...ALTHOUGH TEMPS ARE COOLING...MODELS SHOWING MUCH OF THE OMEGA OCCURRING BELOW THE DGZ...WHICH SHOULD KEEP SNOW RATIOS ON THE LOW SIDE. ONE EXCEPTION WOULD BE OVER THE KEWEENAW...WHERE THE COLDEST TEMPS ARE AND SHOULD PLACE FORCING MORE IN THE DGZ. SECOND...WITH THE SHORTWAVE MOVING THROUGH...MODELS ARE SHOWING SOME DIRECTIONAL SHEAR BETWEEN THE SFC AND H850. THUS...KEPT LES AMNTS UNDER AN INCH. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 437 AM EST FRI FEB 17 2012 UPPER AIR PATTERN CONSISTS OF A 500 MB TROUGH OVER THE GREAT LAKES REGION INTO THE NORTHERN PLAINS WITH A CLOSED LOW OVER THE GULF OF CA AND A RIDGE IS OFF THE WEST COAST. THE TROUGH OVER THE GREAT LAKES REGION WILL GET AMPLIFIED AS A SHORTWAVE DIGS SOUTHEAST INTO THE AREA TONIGHT WITH A SHORTWAVE RIDGE BUILDING INTO THE AREA SAT NIGHT INTO SUNDAY. LAKE EFFECT WILL CONTINUE TO BE GOING ON SATURDAY MORNING BEFORE THE ENVIRONMENT GETS A BIT MORE HOSTILE TO LAKE EFFECT. GFS BUFKIT SOUNDINGS SHOW AN INVERTED-V SOUNDING IN THE LOW LEVELS AT IWD...CMX AND ERY AND INVERSION HEIGHTS FALL IN THE MORNING FROM 3000-4000 FEET. DGZ ALSO FALLS IN HEIGHT AND DEEPER MOISTURE DEPARTS AS DRY AIR COMES IN. OMEGA IN THE DGZ ALSO BECOMES NEGATIVE WITH DOWNWARD MOTION AT THAT TIME SO THE LIKELY POPS IN THE MORNING IN NORTH AFFECT LAKE SUPERIOR LAKE EFFECT SNOW BELTS WILL DECREASE TO CHANCE IN THE AFTERNOON AS THE WINDS BACK MORE TOWARDS THE WEST. WINDS GO WEST TO SOUTHWEST SAT NIGHT SO ANY LINGERING LAKE EFFECT IN THE NORTH WILL PUSH OFFSHORE AND IN THE EAST WILL CONTINUE TO DIMINISH. WITH THE LIGHT SW WINDS ON LAND...TEMPERATURES WILL GET COLD AS IDEAL RADIATIONAL COOLING SETS UP WITH CLEAR SKIES AND LIGHT WINDS. WENT COLDER WITH TEMPERATURES THAN THE GOING FORECAST AND WENT WITH ADJMAV GUIDANCE WHICH LOOKED REASONABLE. SUNDAY AND SUNDAY NIGHT LOOK DRY AND THIS CARRIES INTO MONDAY AS WELL. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST EXCEPT TO LOWER LOW TEMPERATURES FOR SATURDAY NIGHT. IN THE EXTENDED...ECMWF SHOWS A 500 MB TROUGH THAT WILL MOVE INTO THE PLAINS ON MONDAY WITH SPLIT FLOW COMBINING TO FORM A DEEP TROUGH MOVING INTO THE UPPER GREAT LAKES LATE TUE THAT PUSHES THROUGH WITH MORE ENERGY DIGGING INTO THE GREAT LAKES WED NIGHT INTO THU. TEMPERATURES LOOK TO STAY MILD THROUGH THE PERIOD WITH TEMPERATURES ABOVE NORMAL. SYSTEM SNOW FOR MON NIGHT AND TUE. THERE IS A HINT OF SOME LAKE EFFECT FOR THE REST OF THE PERIOD WITH THE GFS SHOWING SOME COLDER AIR COMING IN. THE ECMWF DOES NOT HAVE THE COLDER AIR COMING IN SO NO LAKE EFFECT. AVERAGING THIS OUT WOULD GIVE SLIGHT CHANCE POPS AND THAT IS WHAT WILL BE FORECASTED. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1231 AM EST FRI FEB 17 2012 DURING THE OVERNIGHT...VFR CONDITIONS SHOULD GENERALLY PREVAIL AT KIWD/KCMX/KSAW AS SOMEWHAT DRIER AIR AT THE LOW-LEVELS MOVES ACROSS THE AREA. ATTENTION THEN TURNS TO A FAIRLY WELL-DEFINED SHORTWAVE AND ASSOCIATED SMALL LOW PRES CENTER MOVING INTO NW MN. AS THIS SYSTEM TRACKS EASTWARD...IT`S LOOKING MORE FAVORABLE FOR A RELATIVELY SMALL AREA OF -SN TO DEVELOP INTO WRN UPPER MI IN THE MORNING AND SPREAD E DURING THE DAY. AS A RESULT...EXPECT CONDITIONS AT KIWD TO FALL TO MVFR WITH THE ONSET OF PCPN...AND THERE MAY BE PERIODS OF IFR IN THE EARLY AFTN. KSAW WILL BE ON THE NRN EDGE OF SYSTEM...SO ONLY LOWERED CONDITIONS TO MVFR THERE IN THE MID/LATE AFTN INTO EARLY EVENING. WITH SYSTEM LIKELY PASSING S OF KCMX... ONLY EXPECT SOME FLURRIES AT TIMES OFF THE LAKE ALONG WITH THE DEVELOPMENT OF MVFR CIGS. BETTER CHANCE OF -SHSN WILL DEVELOP AT KCMX DURING THE EVENING AS OVERLAKE INSTABILITY INCREASES. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 437 AM EST FRI FEB 17 2012 NO GALES ARE EXPECTED THROUGH THE PERIOD. THE STRONGEST WINDS THROUGH MID WEEK NEXT WEEK WILL OCCUR THIS MORNING AS NORTHWEST WINDS GUST TO AROUND 30 KTS ON THE PERIPHERY OF A LOW MOVING ACROSS ONTARIO. WITH WARMER TEMPERATURES AND LIGHTER WINDS...FREEZING SPRAY SHOULD NOT BE A PROBLEM EITHER. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...07 AVIATION...ROLFSON MARINE...07
AREA FORECAST DISCUSSION
NWS GLASGOW MT
757 PM MST SAT FEB 18 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH MONDAY... UPDATE...RADAR ECHOES INCREASING OVER CENTRAL MONTANA MOVING INTO PHILLIPS AND PETROLEUM COUNTIES THIS EVENING. THE HRRR MODEL SHOWS THIS AREA OF SNOW SHOWERS MOVING INTO THE CENTRAL SECTIONS OF NORTHEAST MONTANA. DECIDED TO INTRODUCE SCATTERED TO ISOLATED SNOW SHOWERS TO MOST AREAS WITH LITTLE OR NO ACCUMULATION EXPECTED. PROTON AN UPPER TROUGH OVER THE PACIFIC NORTHWEST WILL SPLIT THIS EVENING...LARGELY GOING AROUND NORTHEAST MONTANA TONIGHT INTO SUNDAY. THE FAR SOUTHWEST ZONES WILL BE SKIRTED BY THE SOUTHWARD DIVING HALF OF THE WAVE...BRINGING A FEW LIGHT SNOW SHOWERS. THE NORTHERN HALF OF THE WAVE WILL BECOME STALLED OUT OVER CENTRAL SASKATCHEWAN. THESE LIGHT SHOWERS WILL SPREAD ACROSS THE FAR SOUTH INTO SUNDAY AND BECOME MORE ISOLATED. TEMPERATURES ON SUNDAY WILL BE A FEW DEGREES COOLER ON AVERAGE...BUT WILL CONTINUE TO BE ABOVE NORMALS. SUNDAY NIGHT WILL BRING LIGHT WINDS AND AT LEAST SOME PARTIAL CLEARING. THE AMOUNT OF CLEARING WILL SIGNIFICANTLY AFFECT JUST HOW COLD THINGS CAN GET...ESPECIALLY FOR AREAS WITH LINGERING SNOW COVER. AT THIS POINT ANTICIPATE SOME LINGERING CLOUD COVER SO KEPT TEMPS IN THE TEENS NORTH TO LOW 20S SOUTH. ON MONDAY THE NORTHERN HALF OF TONIGHTS WAVE WILL PUSH EASTWARD DRAGGING A WEAK FRONTAL BOUNDARY THROUGH NORTHEAST MONTANA. LIGHT SNOW FLURRIES WILL BE POSSIBLE ACROSS THE NORTH WITH THIS FEATURE. TEMPS WILL COOL CLOSER TO NORMALS WHILE NORTHWEST WINDS PICK UP AT 10 TO 20 MPH. GILCHRIST .LONG TERM...MONDAY NIGHT THROUGH SATURDAY... ANTICIPATED SYNOPTIC SET UP...LARGE TROUGH EXTENDS FROM THE FOUR CORNERS UP THROUGH THE NORTHERN PLAINS AND INTO THE HUDSON. A LONGWAVE RIDGE EXTENDS OFF THE COAST OF CALIFORNIA INTO BRITISH COLUMBIA AND UP INTO YUKON. ONE MORE LONG WAVE TROUGH IS DESTINED FOR THE WESTERN PACIFIC AND SHOULD MAKE ITS WAY ACROSS THE PACIFIC AND ONTO THE NORTH AMERICAN CONTINENT BY NEXT WEEKEND. LONG TERM WEATHER PATTERN IS LOOKING VERY ACTIVE WITH MULTIPLE CHANCES FOR SNOW SHOWERS. AT THIS TIME THE BEST PERIODS FOR SNOW SHOWERS LOOK TO BE ON TUESDAY NIGHT THROUGH WEDNESDAY... THURSDAY...AND NEXT WEEKEND WITH A POTENTIALLY LARGE STORM. HOWEVER...NORTHWEST FLOW PATTERNS WITH POTENTIALLY UNSTABLE CONDITIONS WILL BE POSSIBLE EACH PERIOD OTHER THAN THE INITIAL MONDAY NIGHT AND THEN FRIDAY. SURPRISINGLY...CONFIDENCE IS HIGH DUE TO ENSEMBLES AMONG DIFFERENT MAIN MODELS BEING FAIRLY CONSISTENT. INTERNAL ENSEMBLES MEMBERS AMONG INDIVIDUAL MODELS ARE DOING GOOD AS WELL. THE MOST STRIKING PLACE WHERE THIS SHOWS IS IN THE LARGER STORM THAT IS ANTICIPATED NEXT WEEKEND. ALL THREE MAIN MODELS THE EC...GFS...AND EVEN GEM ARE PREDICTING A STORM WITH SOME FORM OF NORTHWEST QUADRANT SNOWBELT. OF COARSE THE PERIODS LEADING UP TO THIS STORM HAVE ENOUGH MINOR DIFFERENCES THAT THE CHANGE COULD EASILY KICK THE STORM NORTH OR SOUTH BY A HALF A STATE WHEN NEXT WEEKEND ROLLS AROUND. GAH PREVIOUS LONG TERM DISCUSSION... THE LONG TERM FORECAST STARTS MONDAY NIGHT WITH A LARGE UPPER RIDGE OVER THE THE CENTRAL PACIFIC WITH A LARGE UPPER TROUGH OVER BAJA CALIFORNIA. THIS UPPER TROUGH IS SOMEWHAT SEPARATED FROM THE NW ZONAL FLOW WHICH IS STREAMING IN FROM THE GULF OF ALASKA ACROSS MONTANA AND INTO THE CENTRAL PLAINS. FROM THE LATEST MODEL OUTPUT IT LOOKS LIKE A SHORT WAVE WILL BRING A BURST OF MOISTURE ACROSS MONTANA ON TUESDAY AFTERNOON AND PUSH A COLD FRONT ACROSS CENTRAL MONTANA THAT WILL REMAIN IN PLACE UNTIL LATE ON FRIDAY. THE GFS AND GEM HAVE SLIGHTLY MORE QPF THEN THE GFS IS SHOWING AT THIS POINT. DECIDED TO KEEP THE CHANCE POPS THAT I INHERITED FROM THE LAST SHIFT FROM LATE TUESDAY AFTERNOON IN WEDNESDAY MORNING. SO A CHANCE OF SNOW STARTING TUESDAY AFTERNOON INTO WEDNESDAY MORNING ACROSS NEMONT. EXTENDED MODEL SOLUTIONS INDICATE THAT THIS PATTERN WITH THE ZONAL NW FLOW WILL CONTINUE TO PROVIDE PACIFIC MOISTURE THROUGH FRIDAY. WITH FRONTAL BOUNDARY STRETCHED ACROSS MONTANA THE PACIFIC MOISTURE WILL CONTINUE TO OVERRUN THIS FRONT FROM WEDNESDAY THROUGH FRIDAY. WITH THIS IN MIND LEFT A SLIGHT CHANCE OF SNOW FOR THE OVERNIGHT PERIODS AND A RAIN SNOW MIX FOR THE DAYS THROUGH FRIDAY. PRETTY GOOD MODEL AGREEMENT NEXT WEEKEND AS A LARGE UPPER LOW PLUNGES FROM THE GULF OF ALASKA INTO THE WESTERN HALF OF THE US. THIS SYSTEM COULD PROVIDE MAJOR IMPACTS ACROSS ALL OF MONTANA IF THE MODELS SOLUTIONS ARE ACCURATE. MUCH COLD AIR ALONG WITH ACCUMULATING SNOWFALL COULD BE ON THE MENU FOR NEXT WEEKEND. RSMITH && .AVIATION... MAINLY VFR THROUGH THE TAF CYCLE. SNOW SHOWERS...ALREADY PRESENT ON THE RADAR TO OUR SOUTHWEST AND MOVING TO THE NORTHEAST...COULD CREATE PERIODS OF MVFR ACROSS THE AREA TONIGHT. LIGHT WINDS WILL VEER TO THE WEST OVERNIGHT AND INCREASE TO 5 TO 10 KTS SUNDAY. GAH/SCT && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$ WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
957 PM EST SAT FEB 18 2012 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL BRING SNOW SHOWERS THROUGH THE NIGHT. ACCUMULATIONS WILL BE LIGHT ACROSS MOST OF THE AREA. A FEW LINGERING FLURRIES IN THE FINGER LAKES REGION SUNDAY MORNING...BEFORE HIGH PRESSURE BRINGS QUIET WEATHER THROUGH TUESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 10 PM...LAST PCPN FROM THE SHRT WV IS NOW WELL EAST AND SOUTH OF THE FCST AREA. BOTH THE WRFARW AND THE HRRR SHOW SOME WEAK LE FOR THE NEXT FEW HRS OVER THE NRN FINGER LAKES IN THE NLY FLOW OFF ONTARIO. 88D COMPOSITE DOES SHOW SOME WEAK ECHOES IN THE AREA SO WILL CONT WITH CHANCE POPS IN THAT AREA FOR THE NEXT FEW HRS. 7PM...SHRT WV IS NOW SLIDING EAST OF THE AREA AND WHAT LOOKS LIKE THE LAST ROUND OF SNOW SHWRS IS MVG THRU THE MIDDLE OF THE FCST AREA. BHD THE WV...JUST SOME LIMITED LE SNOW SHWRS XPCTD WITH LTL ACCUM. TOO MUCH SHEAR AND SIMPLY NOT ALL THAT COLD SO NOT MUCH LE XPCTD. PRVS DISC BLO. A WEAK LOW PRESSURE SYSTEM IS CURRENTLY MAKING ITS WAY INTO THE CWA THIS AFTERNOON. IT WILL MAKE IT ACROSS AND WEAK OVERNIGHT TONIGHT. THERE WILL BE SOME SHOWERS WITH THIS SYSTEM, MAINLY IN THE FORM OF SNOW, BUT SOME AREAS, ESPECIALLY IN NEPA, MAY SEE SOME RAIN. CURRENTLY, RADAR RETURNS OVER NEPA ARE NOT REFLECTING WHAT IS BEING REPORTED BY ASOS AT A COUPLE OF SITES. BOTH MSV AND AVP HAD STRONGER RETURNS PASS DIRECTLY OVERHEAD AND NEITHER REPORTED ANY PRECIPITATION. ON THE OTHER HAND, RME HAD SOME LIGHTER RETURNS AND IS REPORTING MODERATE SNOW. SAME WITH ELZ. THIS MAKES FORECASTING POPS A LITTLE TRICKY. BEST GUESS IS SOME VIRGA, WITH FLURRIES/SPRINKLES AND ISOLATED SHOWERS. THIS WILL CONTINUE THROUGH THE AFTERNOON. THE HRRR DID SHOW THIS TYPE OF RETURNS, SO WILL MODEL POPS AFTER THAT, AT LEAST AS GUIDANCE FOR TIMING. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... THIS LOW, AS MENTIONED BEFORE, WILL MOVE ACROSS TONIGHT AND WILL WEAKEN AS IT DOES. SOME COLD AIR ADVECTION WILL FOLLOW BEHIND IT AND MAY KICK OFF SOME LAKE EFFECT SNOW IN THE NORTHERN AND FINGER LAKE ZONES. NOT EXPECTING MORE THEN A COUPLE OF INCHES FROM ANY OF THESE SNOW SHOWERS. BY SUNDAY MORNING, HIGH PRESSURE WILL BEGIN TO BUILD IN AND LAKE EFFECT WILL COME TO AN END SUNDAY MORNING. THIS HIGH PRESSURE WILL KEEP A STRONG LOW PRESSURE SYSTEM WELL TO THE SOUTH OF THE FORECAST AREA. SUNDAY WILL BE THE COOLER DAY, WITH NEAR NORMAL TEMPS IN THE AFTERNOON. THEN, WARM AIR ADVECTION WILL SLOWLY INCREASE TEMPERATURES THROUGH THE MIDDLE OF THE WEEK, WITH UPPER 40S POSSIBLE ON TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... MAIN PLAYER FOR THE PERIOD WILL BE A DEVELOPING MID-LEVEL VORTEX SOUTH OF HUDSON BAY WHICH WILL KEEP MUCH OF THE GREAT LAKES REGION EMBEDDED IN SW FLOW ALOFT. AS IS THE CASE WITH THESE SYNOPTIC SITUATIONS...EMBEDDED SHORTWAVE DISTURBANCES ROTATING ALONG THE SOUTHERN PERIPHERY OF THIS FEATURE WILL RESULT IN AN ACTIVE WX PATTERN FOR MUCH OF THE GREAT LAKES REGION TOWARDS MID/LATE WEEK. GFS AND ECMWF DETERMINISTIC PROGS APPEAR TO BE IN FAIRLY GOOD AGREEMENT TO START OUT THE PERIOD WITH FIRST SHORTWAVE/SFC FRONT EXPECTED TO MOVE THROUGH THE REGION ON WED. WITH ITS ARRIVAL...EXPECT MAINLY A RA/SN MIX WED NGT BEFORE TRANSITIONING TO ALL RA BY LATE WED MORNING/EARLY AFTERNOON. MODELS THEN ADVERTISE A MORE POTENT DISTURBANCE ON THRU AS SECOND SHORTWAVE ROTATES INTO THE REGION. AGAIN...EXPECT RA/SN MIX LATE WED/EARLY THU BEFORE ONCE AGAIN CHANGING OVER TO ALL RA THROUGH THE DAY. MODEL DIFFERENCES DO APPEAR BY THIS POINT HOWEVER AS GFS PHASES BOTH NORTHERN AND SOUTHERN STREAM ENERGY CORES ACROSS THE TENN RVR VLY/SOUTHERN APPALACHIANS BEFORE DEVELOPING A COASTAL LOW BY LATE THU OFF THE HATTERAS COAST. ECMWF ON THE OTHER HAND SHOWS NO INDICATION OF PHASING AND NO SUGGESTION FOR ANY COASTAL DEVELOPMENT. IF THE GFS/S SCENARIO WERE TO PAN OUT...FEATURE LOOKS TO BE A QUICK HITTER WITH MAIN QPF SHIELD REMAINING SOUTH AND EAST OF THE CWA. FUTURE MODEL RUNS MOST CERTAINLY BARE WATCHING. NEXT COLD FRONT EXPECTED TO MOVE THROUGH THE REGION ON FRI WHICH WILL BE FOLLOWED BY THE ARRIVAL OF ARCTIC HIGH PRESSURE AND A CHILLY START FOR NEXT WEEKEND. MODELS SUGGEST H85 TEMPS FALLING TO NEAR -18C WHICH WILL LIKELY RESULT IN A LAKE RESPONSE OFF OF LAKE ONTARIO IN NORTHWEST FLOW ALOFT. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... -SN CONTINUES TO WORK THROUGH THE REGION EARLY THIS EVENING IN RESPONSE TO A DEPARTING SHORTWAVE TROUGH AND SOUTHWARD SAGGING COLD FRONT. FRONT WILL CONTINUE TO PUSH THROUGH THE AREA THIS EVENING WHICH WILL ALLOW WINDS TO SHIFT FROM THE W TO NNW OVERNIGHT. BEHIND THE FEATURE...WEAK COLD AIR ADVECTION OVER THE LAKES WILL RESULT IN LAKE EFFECT CLOUD DEVELOPMENT ACROSS CNY. BASED ON EXPECTED WIND FLOW...BEST PROSPECTS FOR LONG LASTING MVFR CIGS WILL BE AT BOTH ITH/BGM WHERE OCCASIONAL IFR CIGS CANNOT BE RULED OUT AFTER 06Z. PROSPECTS FOR LAKE EFFECT SNOW DEVELOPMENT LOOK MARGINAL AT BEST BASED ON UNFAVORABLE WIND TRAJECTORIES. THAT SAID...CAN/T TOTALLY RULE OUT A PASSING FLURRY OR STRAY SNOW SHWR AT SYR/ITH/BGM OVERNIGHT. CLOUDS SHOULD LINGER UNTIL LATE SUN MORNING AFTER WHICH...SURFACE RIDGING BUILDING IN FROM THE WEST WILL LIKELY LEAD TO SOME CLEARING LATE IN THE DAY. .OUTLOOK... SUN/MON/TUE MORN...MAINLY VFR. SUNDAY POSSIBLE MVFR CIGS AT ITH FROM LAKE INDUCED CLOUDS FROM CAYUGA LAKE. TUE AFTN/THU...MVFR IN MIXED PRECIP. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI NEAR TERM...DGM/SLI SHORT TERM...SLI LONG TERM...CMG AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
728 PM EST SAT FEB 18 2012 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL BRING SNOW SHOWERS THROUGH THE NIGHT. ACCUMULATIONS WILL BE LIGHT ACROSS MOST OF THE AREA. A FEW LINGERING FLURRIES IN THE FINGER LAKES REGION SUNDAY MORNING...BEFORE HIGH PRESSURE BRINGS QUIET WEATHER THROUGH TUESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 7PM...SHRT WV IS NOW SLIDING EAST OF THE AREA AND WHAT LOOKS LIKE THE LAST ROUND OF SNOW SHWRS IS MVG THRU THE MIDDLE OF THE FCST AREA. BHD THE WV...JUST SOME LIMITED LE SNOW SHWRS XPCTD WITH LTL ACCUM. TOO MUCH SHEAR AND SIMPLY NOT ALL THAT COLD SO NOT MUCH LE XPCTD. PRVS DISC BLO. A WEAK LOW PRESSURE SYSTEM IS CURRENTLY MAKING ITS WAY INTO THE CWA THIS AFTERNOON. IT WILL MAKE IT ACROSS AND WEAK OVERNIGHT TONIGHT. THERE WILL BE SOME SHOWERS WITH THIS SYSTEM, MAINLY IN THE FORM OF SNOW, BUT SOME AREAS, ESPECIALLY IN NEPA, MAY SEE SOME RAIN. CURRENTLY, RADAR RETURNS OVER NEPA ARE NOT REFLECTING WHAT IS BEING REPORTED BY ASOS AT A COUPLE OF SITES. BOTH MSV AND AVP HAD STRONGER RETURNS PASS DIRECTLY OVERHEAD AND NEITHER REPORTED ANY PRECIPITATION. ON THE OTHER HAND, RME HAD SOME LIGHTER RETURNS AND IS REPORTING MODERATE SNOW. SAME WITH ELZ. THIS MAKES FORECASTING POPS A LITTLE TRICKY. BEST GUESS IS SOME VIRGA, WITH FLURRIES/SPRINKLES AND ISOLATED SHOWERS. THIS WILL CONTINUE THROUGH THE AFTERNOON. THE HRRR DID SHOW THIS TYPE OF RETURNS, SO WILL MODEL POPS AFTER THAT, AT LEAST AS GUIDANCE FOR TIMING. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... THIS LOW, AS MENTIONED BEFORE, WILL MOVE ACROSS TONIGHT AND WILL WEAKEN AS IT DOES. SOME COLD AIR ADVECTION WILL FOLLOW BEHIND IT AND MAY KICK OFF SOME LAKE EFFECT SNOW IN THE NORTHERN AND FINGER LAKE ZONES. NOT EXPECTING MORE THEN A COUPLE OF INCHES FROM ANY OF THESE SNOW SHOWERS. BY SUNDAY MORNING, HIGH PRESSURE WILL BEGIN TO BUILD IN AND LAKE EFFECT WILL COME TO AN END SUNDAY MORNING. THIS HIGH PRESSURE WILL KEEP A STRONG LOW PRESSURE SYSTEM WELL TO THE SOUTH OF THE FORECAST AREA. SUNDAY WILL BE THE COOLER DAY, WITH NEAR NORMAL TEMPS IN THE AFTERNOON. THEN, WARM AIR ADVECTION WILL SLOWLY INCREASE TEMPERATURES THROUGH THE MIDDLE OF THE WEEK, WITH UPPER 40S POSSIBLE ON TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... MAIN PLAYER FOR THE PERIOD WILL BE A DEVELOPING MID-LEVEL VORTEX SOUTH OF HUDSON BAY WHICH WILL KEEP MUCH OF THE GREAT LAKES REGION EMBEDDED IN SW FLOW ALOFT. AS IS THE CASE WITH THESE SYNOPTIC SITUATIONS...EMBEDDED SHORTWAVE DISTURBANCES ROTATING ALONG THE SOUTHERN PERIPHERY OF THIS FEATURE WILL RESULT IN AN ACTIVE WX PATTERN FOR MUCH OF THE GREAT LAKES REGION TOWARDS MID/LATE WEEK. GFS AND ECMWF DETERMINISTIC PROGS APPEAR TO BE IN FAIRLY GOOD AGREEMENT TO START OUT THE PERIOD WITH FIRST SHORTWAVE/SFC FRONT EXPECTED TO MOVE THROUGH THE REGION ON WED. WITH ITS ARRIVAL...EXPECT MAINLY A RA/SN MIX WED NGT BEFORE TRANSITIONING TO ALL RA BY LATE WED MORNING/EARLY AFTERNOON. MODELS THEN ADVERTISE A MORE POTENT DISTURBANCE ON THRU AS SECOND SHORTWAVE ROTATES INTO THE REGION. AGAIN...EXPECT RA/SN MIX LATE WED/EARLY THU BEFORE ONCE AGAIN CHANGING OVER TO ALL RA THROUGH THE DAY. MODEL DIFFERENCES DO APPEAR BY THIS POINT HOWEVER AS GFS PHASES BOTH NORTHERN AND SOUTHERN STREAM ENERGY CORES ACROSS THE TENN RVR VLY/SOUTHERN APPALACHIANS BEFORE DEVELOPING A COASTAL LOW BY LATE THU OFF THE HATTERAS COAST. ECMWF ON THE OTHER HAND SHOWS NO INDICATION OF PHASING AND NO SUGGESTION FOR ANY COASTAL DEVELOPMENT. IF THE GFS/S SCENARIO WERE TO PAN OUT...FEATURE LOOKS TO BE A QUICK HITTER WITH MAIN QPF SHIELD REMAINING SOUTH AND EAST OF THE CWA. FUTURE MODEL RUNS MOST CERTAINLY BARE WATCHING. NEXT COLD FRONT EXPECTED TO MOVE THROUGH THE REGION ON FRI WHICH WILL BE FOLLOWED BY THE ARRIVAL OF ARCTIC HIGH PRESSURE AND A CHILLY START FOR NEXT WEEKEND. MODELS SUGGEST H85 TEMPS FALLING TO NEAR -18C WHICH WILL LIKELY RESULT IN A LAKE RESPONSE OFF OF LAKE ONTARIO IN NORTHWEST FLOW ALOFT. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... -SN CONTINUES TO WORK THROUGH THE REGION EARLY THIS EVENING IN RESPONSE TO A DEPARTING SHORTWAVE TROUGH AND SOUTHWARD SAGGING COLD FRONT. FRONT WILL CONTINUE TO PUSH THROUGH THE AREA THIS EVENING WHICH WILL ALLOW WINDS TO SHIFT FROM THE W TO NNW OVERNIGHT. BEHIND THE FEATURE...WEAK COLD AIR ADVECTION OVER THE LAKES WILL RESULT IN LAKE EFFECT CLOUD DEVELOPMENT ACROSS CNY. BASED ON EXPECTED WIND FLOW...BEST PROSPECTS FOR LONG LASTING MVFR CIGS WILL BE AT BOTH ITH/BGM WHERE OCCASIONAL IFR CIGS CANNOT BE RULED OUT AFTER 06Z. PROSPECTS FOR LAKE EFFECT SNOW DEVELOPMENT LOOK MARGINAL AT BEST BASED ON UNFAVORABLE WIND TRAJECTORIES. THAT SAID...CAN/T TOTALLY RULE OUT A PASSING FLURRY OR STRAY SNOW SHWR AT SYR/ITH/BGM OVERNIGHT. CLOUDS SHOULD LINGER UNTIL LATE SUN MORNING AFTER WHICH...SURFACE RIDGING BUILDING IN FROM THE WEST WILL LIKELY LEAD TO SOME CLEARING LATE IN THE DAY. .OUTLOOK... SUN/MON/TUE MORN...MAINLY VFR. SUNDAY POSSIBLE MVFR CIGS AT ITH FROM LAKE INDUCED CLOUDS FROM CAYUGA LAKE. TUE AFTN/THU...MVFR IN MIXED PRECIP. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI NEAR TERM...DGM/SLI SHORT TERM...SLI LONG TERM...CMG AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
657 PM EST SAT FEB 18 2012 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL BRING SNOW SHOWERS THROUGH THE NIGHT. ACCUMULATIONS WILL BE LIGHT ACROSS MOST OF THE AREA. A FEW LINGERING FLURRIES IN THE FINGER LAKES REGION SUNDAY MORNING...BEFORE HIGH PRESSURE BRINGS QUIET WEATHER THROUGH TUESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A WEAK LOW PRESSURE SYSTEM IS CURRENTLY MAKING ITS WAY INTO THE CWA THIS AFTERNOON. IT WILL MAKE IT ACROSS AND WEAK OVERNIGHT TONIGHT. THERE WILL BE SOME SHOWERS WITH THIS SYSTEM, MAINLY IN THE FORM OF SNOW, BUT SOME AREAS, ESPECIALLY IN NEPA, MAY SEE SOME RAIN. CURRENTLY, RADAR RETURNS OVER NEPA ARE NOT REFLECTING WHAT IS BEING REPORTED BY ASOS AT A COUPLE OF SITES. BOTH MSV AND AVP HAD STRONGER RETURNS PASS DIRECTLY OVERHEAD AND NEITHER REPORTED ANY PRECIPITATION. ON THE OTHER HAND, RME HAD SOME LIGHTER RETURNS AND IS REPORTING MODERATE SNOW. SAME WITH ELZ. THIS MAKES FORECASTING POPS A LITTLE TRICKY. BEST GUESS IS SOME VIRGA, WITH FLURRIES/SPRINKLES AND ISOLATED SHOWERS. THIS WILL CONTINUE THROUGH THE AFTERNOON. THE HRRR DID SHOW THIS TYPE OF RETURNS, SO WILL MODEL POPS AFTER THAT, AT LEAST AS GUIDANCE FOR TIMING. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... THIS LOW, AS MENTIONED BEFORE, WILL MOVE ACROSS TONIGHT AND WILL WEAKEN AS IT DOES. SOME COLD AIR ADVECTION WILL FOLLOW BEHIND IT AND MAY KICK OFF SOME LAKE EFFECT SNOW IN THE NORTHERN AND FINGER LAKE ZONES. NOT EXPECTING MORE THEN A COUPLE OF INCHES FROM ANY OF THESE SNOW SHOWERS. BY SUNDAY MORNING, HIGH PRESSURE WILL BEGIN TO BUILD IN AND LAKE EFFECT WILL COME TO AN END SUNDAY MORNING. THIS HIGH PRESSURE WILL KEEP A STRONG LOW PRESSURE SYSTEM WELL TO THE SOUTH OF THE FORECAST AREA. SUNDAY WILL BE THE COOLER DAY, WITH NEAR NORMAL TEMPS IN THE AFTERNOON. THEN, WARM AIR ADVECTION WILL SLOWLY INCREASE TEMPERATURES THROUGH THE MIDDLE OF THE WEEK, WITH UPPER 40S POSSIBLE ON TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... MAIN PLAYER FOR THE PERIOD WILL BE A DEVELOPING MID-LEVEL VORTEX SOUTH OF HUDSON BAY WHICH WILL KEEP MUCH OF THE GREAT LAKES REGION EMBEDDED IN SW FLOW ALOFT. AS IS THE CASE WITH THESE SYNOPTIC SITUATIONS...EMBEDDED SHORTWAVE DISTURBANCES ROTATING ALONG THE SOUTHERN PERIPHERY OF THIS FEATURE WILL RESULT IN AN ACTIVE WX PATTERN FOR MUCH OF THE GREAT LAKES REGION TOWARDS MID/LATE WEEK. GFS AND ECMWF DETERMINISTIC PROGS APPEAR TO BE IN FAIRLY GOOD AGREEMENT TO START OUT THE PERIOD WITH FIRST SHORTWAVE/SFC FRONT EXPECTED TO MOVE THROUGH THE REGION ON WED. WITH ITS ARRIVAL...EXPECT MAINLY A RA/SN MIX WED NGT BEFORE TRANSITIONING TO ALL RA BY LATE WED MORNING/EARLY AFTERNOON. MODELS THEN ADVERTISE A MORE POTENT DISTURBANCE ON THRU AS SECOND SHORTWAVE ROTATES INTO THE REGION. AGAIN...EXPECT RA/SN MIX LATE WED/EARLY THU BEFORE ONCE AGAIN CHANGING OVER TO ALL RA THROUGH THE DAY. MODEL DIFFERENCES DO APPEAR BY THIS POINT HOWEVER AS GFS PHASES BOTH NORTHERN AND SOUTHERN STREAM ENERGY CORES ACROSS THE TENN RVR VLY/SOUTHERN APPALACHIANS BEFORE DEVELOPING A COASTAL LOW BY LATE THU OFF THE HATTERAS COAST. ECMWF ON THE OTHER HAND SHOWS NO INDICATION OF PHASING AND NO SUGGESTION FOR ANY COASTAL DEVELOPMENT. IF THE GFS/S SCENARIO WERE TO PAN OUT...FEATURE LOOKS TO BE A QUICK HITTER WITH MAIN QPF SHIELD REMAINING SOUTH AND EAST OF THE CWA. FUTURE MODEL RUNS MOST CERTAINLY BARE WATCHING. NEXT COLD FRONT EXPECTED TO MOVE THROUGH THE REGION ON FRI WHICH WILL BE FOLLOWED BY THE ARRIVAL OF ARCTIC HIGH PRESSURE AND A CHILLY START FOR NEXT WEEKEND. MODELS SUGGEST H85 TEMPS FALLING TO NEAR -18C WHICH WILL LIKELY RESULT IN A LAKE RESPONSE OFF OF LAKE ONTARIO IN NORTHWEST FLOW ALOFT. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... -SN CONTINUES TO WORK THROUGH THE REGION EARLY THIS EVENING IN RESPONSE TO A DEPARTING SHORTWAVE TROUGH AND SOUTHWARD SAGGING COLD FRONT. FRONT WILL CONTINUE TO PUSH THROUGH THE AREA THIS EVENING WHICH WILL ALLOW WINDS TO SHIFT FROM THE W TO NNW OVERNIGHT. BEHIND THE FEATURE...WEAK COLD AIR ADVECTION OVER THE LAKES WILL RESULT IN LAKE EFFECT CLOUD DEVELOPMENT ACROSS CNY. BASED ON EXPECTED WIND FLOW...BEST PROSPECTS FOR LONG LASTING MVFR CIGS WILL BE AT BOTH ITH/BGM WHERE OCCASIONAL IFR CIGS CANNOT BE RULED OUT AFTER 06Z. PROSPECTS FOR LAKE EFFECT SNOW DEVELOPMENT LOOK MARGINAL AT BEST BASED ON UNFAVORABLE WIND TRAJECTORIES. THAT SAID...CAN/T TOTALLY RULE OUT A PASSING FLURRY OR STRAY SNOW SHWR AT SYR/ITH/BGM OVERNIGHT. CLOUDS SHOULD LINGER UNTIL LATE SUN MORNING AFTER WHICH...SURFACE RIDGING BUILDING IN FROM THE WEST WILL LIKELY LEAD TO SOME CLEARING LATE IN THE DAY. .OUTLOOK... SUN/MON/TUE MORN...MAINLY VFR. SUNDAY POSSIBLE MVFR CIGS AT ITH FROM LAKE INDUCED CLOUDS FROM CAYUGA LAKE. TUE AFTN/THU...MVFR IN MIXED PRECIP. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI NEAR TERM...SLI SHORT TERM...SLI LONG TERM...CMG AVIATION...CMG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
921 PM CST SAT FEB 18 2012 .DISCUSSION...MAIN PROBLEM THIS EVENING WILL BE TEMPERATURES. MAINLY CLEAR SKIES ACROSS CENTRAL NORTH DAKOTA WITH INCREASING HIGH LEVEL CLOUDINESS THE WEST. WITH CLEAR SKIES AND LIGHT WINDS...TEMPERATURES HAVE FALLEN INTO THE LOW TO MID 20S ALONG AND EAST OF THE HIGHWAY 83 CORRIDOR. CURRENT DEWPOINTS ARE IN THE MID TO UPPER TEENS. OVERNIGHT LOWS ARE MOSTLY IN THE LOWER 20S AND THINK A DROP IN OVERNIGHT LOWS TO AROUND 20 OR THE UPPER TEENS SEEMS REASONABLE. TEMPERATURES WEST LOOK REASONABLE WITH THE INCREASING CLOUDINESS. MADE SOME MINOR ADJUSTMENTS FOR A QUICKER INCREASE IN CLOUDS FROM WEST TO EAST THAN PREVIOUSLY FORECAST. OTHERWISE FORECAST LOOKS IN GOOD SHAPE. LATEST HRRR GUIDANCE SHOWS THE AREA OF LIGHT SNOW IN CENTRAL MONTANA DISSIPATING AS IT APPROACHES THE NORTH DAKOTA BORDER. A SCATTERED FLURRY COULD DEVELOP WEST AFTER MIDNIGHT...BUT WILL CONTINUE WITH NO MENTION OF PRECIPITATION FOR NOW. && .AVIATION...SOUTHERLY SURFACE FLOW WILL CONTINUE TONIGHT WITH INCREASING MID AND HIGH LEVEL CLOUDINESS MOVING WEST TO EAST ACROSS THE AREA. WINDS WILL SHIFT WEST AT DICKINSON AND WILLISTON ON SUNDAY WITH THE PASSAGE OF A WEAK SURFACE TROUGH. FLOW WILL REMAIN SOUTH TO SOUTHEAST ACROSS CENTRAL NORTH DAKOTA. MID AND HIGH LEVEL CLOUDINESS WILL CONTINUE TO INCREASE...BUT VFR CONDITIONS ARE EXPECTED THROUGH 00 UTC MONDAY. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ TWH
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
911 PM CST SAT FEB 18 2012 .UPDATE... THE UPPER LOW NOW IS MOVING THROUGH EAST TEXAS WITH RAIN DIMINISHING WEST TO EAST ACROSS NORTH AND CENTRAL TEXAS. DECIDED TO EXTEND SOME LIGHT RAIN OVER THE FAR EASTERN COUNTIES BETWEEN MIDNIGHT THROUGH 3AM. OTHERWISE THE RAIN WILL BE OVER FOR THE REST OF THE CWA AT MIDNIGHT. DO NOT SEE ANY NEED TO MAKE ANY ADDITIONAL CHANGES TO THE REST OF THE FORECAST. A PNS WITH REGIONAL RAINFALL TOTALS WAS SENT OUT EARLIER THIS EVENING. ANOTHER ONE WILL LIKELY BE SENT TOMORROW MORNING. 75 && .AVIATION... FOR THE 00Z TAFS...WIDESPREAD LIGHT RAINFALL AND ASSOCIATED FLIGHT CATEGORY RESTRICTIONS ARE THE PRIMARY FORECAST CONCERNS. WIDESPREAD LIGHT RAIN REMAINS IN PLACE OVER METROPLEX AREA TAF SITES AT THE TIME OF THIS DISCUSSION. RAINFALL HAS BEEN DIMINISHING IN INTENSITY FROM THE NORTHWEST FOR THE PAST COUPLE OF HOURS...AND EXPECT THIS TREND TO CONTINUE EARLY ON IN THE FORECAST PERIOD WITH THE UPPER LOW MOVING EAST OF THE METROPLEX. HAVE RAINFALL COMING TO AN END IN THE 02 TO 03Z TIME FRAME RIGHT NOW BASED ON THE MOVEMENT OF THE UPPER LOW...BUT WILL AMEND BASED ON TRACKING THE BACK EDGE OF THE PRECIPITATION SHIELD OVER THE NEXT HOUR OR SO AS THE UPPER LOW EXITS THE AREA. CEILING TRENDS ARE DIFFICULT TO GAUGE IN THE SHORT TERM. OBSERVATIONS IN THE METROPLEX AND UPSTREAM INDICATE MOSTLY LOW VFR CIGS WITH ISOLATED POCKETS OF LOW MVFR TO IFR CIGS. WENT AHEAD WITH AN OPTIMISTIC FORECAST FOR NOW WITH CIGS ONLY FALLING TO 2500 FT AS RAIN DIMINISHES THIS EVENING. THINK THAT CIGS WILL CONTINUE TO FALL DURING THE OVERNIGHT HRS...BUT WILL HOLD OFF ON MENTIONING IFR CONDITIONS FOR SUNDAY MORNING AS CIGS HAVE BEEN HOLDING UP MUCH HIGHER THAN WHAT LAMP GUIDANCE SUGGESTS WITH THIS EVENT. THE LATEST RUN OF THE HRRR REFLECTS DIFFICULTIES IN DETERMINING A FLIGHT CATEGORY THIS EVENING AS IT INDICATES POCKETS OF LIFR CIGS INTERSPERSED WITH VFR CONDITIONS. IN GENERAL THINK THAT WITH MUCH OF THE REGION GETTING A GOOD SOAKING OF 1 TO 2 INCHES OF RAIN...SOME FLIGHT RESTRICTIONS ARE LIKELY TONIGHT DUE TO COOLING TEMPERATURES AND A LACK OF SIGNIFICANTLY DRY AIR TO THE NORTH. EXPECT VFR CONDITIONS TO RETURN TO THE REGION BY LATE SUNDAY MORNING AS STRONGER SUBSIDENCE BUILDS OVER NORTH TX. CAVANAUGH && .PREV DISCUSSION... /ISSUED 307 PM CST SAT FEB 18 2012/ UPPER LEVEL LOW IS IN THE PROCESS OF TRACKING THROUGH THE SOUTHERN CWA AND SHOULD BE OUT OF THE CWA AFTER MIDNIGHT. EXTENSIVE WRAP AROUND RAINS CONTINUE ON THE NORTH AND NORTHWEST SIDE OF THE LOW. THESE RAINS WILL CONTINUE INTO THE EARLY EVENING HOURS BEFORE ENDING FROM WEST TO EAST...AND OUT OF THE EASTERN ZONES BY MIDNIGHT. ADDITIONAL RAINFALL AMOUNTS FROM NOW THROUGH MIDNIGHT WILL AVERAGE 1/4 TO 1/2 INCH...WITH THE HIGHER AMOUNTS FALLING GENERALLY ACROSS THE CENTRAL AND NORTHEASTERN ZONES. CLOUDS LOOK LIKE THEY WILL HOLD IN THROUGH SUNRISE FOR MOST LOCATIONS...BUT NORTHERLY WINDS WILL RESULT IN COLD ADVECTION AND COOLING TEMPS TO NEAR 40 DEGREES BY EARLY SUNDAY MORNING. GENERALLY SUNNY AND PLEASANT WEATHER IS EXPECTED TOMORROW WITH LIGHT NORTH WINDS VEERING BACK TO THE SOUTHEAST DURING THE DAY. HIGHS SHOULD REACH THE UPPER 50S TO LOW 60S. SOUTH WINDS INCREASE SUNDAY NIGHT...AND ESPECIALLY INTO MONDAY WHEN THEY WILL REACH 15 TO 25 MPH AND GUSTY. THIS IS ALL IN RESPONSE TO A FAST MOVING SHORTWAVE THAT WILL CROSS THE SOUTHERN PLAINS ON MONDAY. GULF MOISTURE FOR LOW CLOUD COVER WILL NOT ARRIVE UNTIL MONDAY MORNING...AND THE ATMOSPHERE WILL HAVE LITTLE TIME TO RECHARGE AND DESTABILIZE AHEAD OF AN EASTWARD MOVING DRY LINE MONDAY AFTERNOON. THERE IS A RATHER STRONG THERMAL INVERSION NEAR 600MB...WHICH TECHNICALLY WOULD BE CLASSIFIED AS THE EQUILIBRIUM LEVEL AND NOT A CAP SINCE THERE IS 100-200J/KG SURFACE BASED CAPE AVAILABLE BELOW IT. ANY CONVECTION THAT DEVELOPS WOULD BE LOW-TOPPED...AND NOT CONTAIN ICE PARTICLES...WHICH IS NEEDED FOR LIGHTNING. THUS WILL KEEP LOW CHANCES OF SHOWERS MONDAY AFTERNOON AND NIGHT MAINLY OVER THE EASTERN ZONES...WITH THE BEST CHANCES IN THE NORTHEAST. WEAK COLD FRONT WILL MOVE THROUGH THE REGION MONDAY NIGHT WITH WINDS SWITCHING TO THE NORTHWEST BRIEFLY...BUT COMING BACK TO THE SOUTH BY TUESDAY NIGHT. HIGH TEMPS TUESDAY WILL BE WARMER THAN MONDAY DUE TO SUNSHINE AND WESTERLY WINDS. ANOTHER SHORTWAVE WILL MOVE THROUGH TUESDAY NIGHT AND WEDNESDAY...BUT IT APPEARS MOISTURE WILL BE TOO LIMITED FOR ANYTHING OTHER THAN SOME MID CLOUDS. LONG RANGE GUIDANCE IS STILL WAVERING ON THE FATE OF AN UPPER LOW OFF THE BAJA COASTLINE LATE IN THE WEEK. MOST OF THE GUIDANCE EJECTS THIS LOW ACROSS SOUTH TEXAS IN A WEAKENED STATE...AND THUS KEEP ANY CHANCE OF MOISTURE RETURN OR RAIN WELL SOUTH OF THE AREA. SOME OF THE GFS RUNS WERE SHOWING THIS FEATURE COMING ACROSS FARTHER NORTH...AND THEREFORE WILL KEEP POPS AT 10 PERCENT THURSDAY AND FRIDAY. REGARDLESS OF WHAT THE PACIFIC LOW DOES...A COLD FRONT SHOULD MOVE THROUGH THURSDAY NIGHT WITH SLIGHTLY COOLER TEMPS FOR FRIDAY AND NEXT WEEKEND. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 40 60 45 63 41 / 80 0 0 10 20 WACO, TX 40 60 44 63 42 / 40 0 0 10 10 PARIS, TX 39 57 39 60 46 / 100 0 0 10 40 DENTON, TX 37 59 44 62 39 / 40 0 0 10 20 MCKINNEY, TX 38 58 40 62 41 / 90 0 0 10 30 DALLAS, TX 41 60 45 63 42 / 90 0 0 10 20 TERRELL, TX 41 59 43 62 43 / 100 0 0 10 20 CORSICANA, TX 41 60 44 63 47 / 80 0 0 10 20 TEMPLE, TX 40 62 43 64 44 / 20 0 0 10 10 MINERAL WELLS, TX 35 61 42 65 38 / 20 0 0 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /75
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
612 PM CST SAT FEB 18 2012 .AVIATION... FOR THE 00Z TAFS...WIDESPREAD LIGHT RAINFALL AND ASSOCIATED FLIGHT CATEGORY RESTRICTIONS ARE THE PRIMARY FORECAST CONCERNS. WIDESPREAD LIGHT RAIN REMAINS IN PLACE OVER METROPLEX AREA TAF SITES AT THE TIME OF THIS DISCUSSION. RAINFALL HAS BEEN DIMINISHING IN INTENSITY FROM THE NORTHWEST FOR THE PAST COUPLE OF HOURS...AND EXPECT THIS TREND TO CONTINUE EARLY ON IN THE FORECAST PERIOD WITH THE UPPER LOW MOVING EAST OF THE METROPLEX. HAVE RAINFALL COMING TO AN END IN THE 02 TO 03Z TIME FRAME RIGHT NOW BASED ON THE MOVEMENT OF THE UPPER LOW...BUT WILL AMEND BASED ON TRACKING THE BACK EDGE OF THE PRECIPITATION SHIELD OVER THE NEXT HOUR OR SO AS THE UPPER LOW EXITS THE AREA. CEILING TRENDS ARE DIFFICULT TO GAUGE IN THE SHORT TERM. OBSERVATIONS IN THE METROPLEX AND UPSTREAM INDICATE MOSTLY LOW VFR CIGS WITH ISOLATED POCKETS OF LOW MVFR TO IFR CIGS. WENT AHEAD WITH AN OPTIMISTIC FORECAST FOR NOW WITH CIGS ONLY FALLING TO 2500 FT AS RAIN DIMINISHES THIS EVENING. THINK THAT CIGS WILL CONTINUE TO FALL DURING THE OVERNIGHT HRS...BUT WILL HOLD OFF ON MENTIONING IFR CONDITIONS FOR SUNDAY MORNING AS CIGS HAVE BEEN HOLDING UP MUCH HIGHER THAN WHAT LAMP GUIDANCE SUGGESTS WITH THIS EVENT. THE LATEST RUN OF THE HRRR REFLECTS DIFFICULTIES IN DETERMINING A FLIGHT CATEGORY THIS EVENING AS IT INDICATES POCKETS OF LIFR CIGS INTERSPERSED WITH VFR CONDITIONS. IN GENERAL THINK THAT WITH MUCH OF THE REGION GETTING A GOOD SOAKING OF 1 TO 2 INCHES OF RAIN...SOME FLIGHT RESTRICTIONS ARE LIKELY TONIGHT DUE TO COOLING TEMPERATURES AND A LACK OF SIGNIFICANTLY DRY AIR TO THE NORTH. EXPECT VFR CONDITIONS TO RETURN TO THE REGION BY LATE SUNDAY MORNING AS STRONGER SUBSIDENCE BUILDS OVER NORTH TX. CAVANAUGH && .PREV DISCUSSION... /ISSUED 307 PM CST SAT FEB 18 2012/ UPPER LEVEL LOW IS IN THE PROCESS OF TRACKING THROUGH THE SOUTHERN CWA AND SHOULD BE OUT OF THE CWA AFTER MIDNIGHT. EXTENSIVE WRAP AROUND RAINS CONTINUE ON THE NORTH AND NORTHWEST SIDE OF THE LOW. THESE RAINS WILL CONTINUE INTO THE EARLY EVENING HOURS BEFORE ENDING FROM WEST TO EAST...AND OUT OF THE EASTERN ZONES BY MIDNIGHT. ADDITIONAL RAINFALL AMOUNTS FROM NOW THROUGH MIDNIGHT WILL AVERAGE 1/4 TO 1/2 INCH...WITH THE HIGHER AMOUNTS FALLING GENERALLY ACROSS THE CENTRAL AND NORTHEASTERN ZONES. CLOUDS LOOK LIKE THEY WILL HOLD IN THROUGH SUNRISE FOR MOST LOCATIONS...BUT NORTHERLY WINDS WILL RESULT IN COLD ADVECTION AND COOLING TEMPS TO NEAR 40 DEGREES BY EARLY SUNDAY MORNING. GENERALLY SUNNY AND PLEASANT WEATHER IS EXPECTED TOMORROW WITH LIGHT NORTH WINDS VEERING BACK TO THE SOUTHEAST DURING THE DAY. HIGHS SHOULD REACH THE UPPER 50S TO LOW 60S. SOUTH WINDS INCREASE SUNDAY NIGHT...AND ESPECIALLY INTO MONDAY WHEN THEY WILL REACH 15 TO 25 MPH AND GUSTY. THIS IS ALL IN RESPONSE TO A FAST MOVING SHORTWAVE THAT WILL CROSS THE SOUTHERN PLAINS ON MONDAY. GULF MOISTURE FOR LOW CLOUD COVER WILL NOT ARRIVE UNTIL MONDAY MORNING...AND THE ATMOSPHERE WILL HAVE LITTLE TIME TO RECHARGE AND DESTABILIZE AHEAD OF AN EASTWARD MOVING DRY LINE MONDAY AFTERNOON. THERE IS A RATHER STRONG THERMAL INVERSION NEAR 600MB...WHICH TECHNICALLY WOULD BE CLASSIFIED AS THE EQUILIBRIUM LEVEL AND NOT A CAP SINCE THERE IS 100-200J/KG SURFACE BASED CAPE AVAILABLE BELOW IT. ANY CONVECTION THAT DEVELOPS WOULD BE LOW-TOPPED...AND NOT CONTAIN ICE PARTICLES...WHICH IS NEEDED FOR LIGHTNING. THUS WILL KEEP LOW CHANCES OF SHOWERS MONDAY AFTERNOON AND NIGHT MAINLY OVER THE EASTERN ZONES...WITH THE BEST CHANCES IN THE NORTHEAST. WEAK COLD FRONT WILL MOVE THROUGH THE REGION MONDAY NIGHT WITH WINDS SWITCHING TO THE NORTHWEST BRIEFLY...BUT COMING BACK TO THE SOUTH BY TUESDAY NIGHT. HIGH TEMPS TUESDAY WILL BE WARMER THAN MONDAY DUE TO SUNSHINE AND WESTERLY WINDS. ANOTHER SHORTWAVE WILL MOVE THROUGH TUESDAY NIGHT AND WEDNESDAY...BUT IT APPEARS MOISTURE WILL BE TOO LIMITED FOR ANYTHING OTHER THAN SOME MID CLOUDS. LONG RANGE GUIDANCE IS STILL WAVERING ON THE FATE OF AN UPPER LOW OFF THE BAJA COASTLINE LATE IN THE WEEK. MOST OF THE GUIDANCE EJECTS THIS LOW ACROSS SOUTH TEXAS IN A WEAKENED STATE...AND THUS KEEP ANY CHANCE OF MOISTURE RETURN OR RAIN WELL SOUTH OF THE AREA. SOME OF THE GFS RUNS WERE SHOWING THIS FEATURE COMING ACROSS FARTHER NORTH...AND THEREFORE WILL KEEP POPS AT 10 PERCENT THURSDAY AND FRIDAY. REGARDLESS OF WHAT THE PACIFIC LOW DOES...A COLD FRONT SHOULD MOVE THROUGH THURSDAY NIGHT WITH SLIGHTLY COOLER TEMPS FOR FRIDAY AND NEXT WEEKEND. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 40 60 45 63 41 / 80 0 0 10 20 WACO, TX 40 60 44 63 42 / 40 0 0 10 10 PARIS, TX 39 57 39 60 46 / 100 0 0 10 40 DENTON, TX 37 59 44 62 39 / 40 0 0 10 20 MCKINNEY, TX 38 58 40 62 41 / 90 0 0 10 30 DALLAS, TX 41 60 45 63 42 / 90 0 0 10 20 TERRELL, TX 41 59 43 62 43 / 100 0 0 10 20 CORSICANA, TX 41 60 44 63 47 / 80 0 0 10 20 TEMPLE, TX 40 62 43 64 44 / 20 0 0 10 10 MINERAL WELLS, TX 35 61 42 65 38 / 20 0 0 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ /
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1144 AM CST FRI FEB 17 2012 .AVIATION... SHOWERS CURRENTLY DETECTED ON KAMA 88D CONTINUE TO MOVE NORTHEAST AT AROUND 30 KT. THESE SHOWERS WILL MOST LIKELY AFFECT KAMA IN THE VERY NEAR TERM...WITH POTENTIAL FOR INCREASED DEVELOPMENT NEAR NORTHERN TERMINALS DURING LATE AFTERNOON AND EARLY EVENING...DUE TO ENHANCED CONVERGENCE AND HIGHER INSTABILITY. DO NOT EXPECT THUNDER NEXT 24 HOURS. VFR CEILINGS EXPECTED TO PREVAIL THROUGH MOST OF THE AFTERNOON. MVFR CEILINGS DEVELOP BEFORE 00Z SATURDAY AT KAMA AND KDHT...AND AROUND 03Z SATURDAY AT KGUY. FURTHER DETERIORATION EXPECTED OVERNIGHT...WITH IFR CEILINGS AND VISIBILITIES DEVELOPING AT ALL TAF SITES THIS EVENING. COLD FRONT STILL EXPECTED TO PASS THROUGH TERMINALS BETWEEN 06Z AND 08Z SATURDAY...WITH SURFACE WINDS SHIFTING TO THE NORTH. DRIER AIR FOLLOWS FRONTAL PASSAGE...WITH IMPROVEMENT BEGINNING AFTER 15Z SATURDAY. COCKRELL && .PREV DISCUSSION... /ISSUED 735 AM CST FRI FEB 17 2012/ UPDATE... ADDED SLIGHT CHANCE OF SNOW SHOWERS BETWEEN 9 AM AND NOON CST TODAY ON THE CAPROCK MAINLY ALONG AND SOUTH OF I-40 INCLUDING AMARILLO... CANYON...HEREFORD...VEGA...PANHANDLE...CLAUDE...AND PAMPA. DISCUSSION... LIGHT PRECIPITATION...MAINLY IN THE FORM OF LIGHT RAIN...CONTINUES TO MOVE NORTHEAST AND INTO THE SOUTH TEXAS PANHANDLE THIS MORNING. MADE THE ADJUSTMENTS ABOVE AS LATEST KLBB RADAR INDICATED BRIGHT BANDING AS LOW AS 600 FT AGL JUST NORTHWEST OF LUBBOCK. APPEARS THIS HEAVIER ACTIVITY MAY COOL THE LOWEST 5000 FT OF THE ATMOSPHERE ENOUGH TO ALLOW FOR LIGHT SNOW TO MIX WITH THE LIGHT RAIN ACROSS THE SOUTH CENTRAL AND SOUTHWEST TEXAS PANHANDLES BETWEEN 9 AM AND NOON CST INCLUDING AMARILLO. WITH WARM SURFACE TEMPERATURES ABOVE FREEZING/32 DEGREES...IF ANY SNOW OCCURS...NO ACCUMULATIONS ARE EXPECTED. STILL BELIEVE LIGHT RAIN WILL BE THE PREDOMINANT PRECIPITATION TYPE THIS MORNING. SOME MID/UPPER DRY SLOTTING MOVING INTO THE PANHANDLES MAY LIMIT PRECIPITATION CHANCES THIS AFTERNOON. BY MIDDAY TODAY...SURFACE TEMPERATURES WILL LIKELY BE TOO WARM TO SUPPORT ANYTHING BUT LIGHT RAIN. PRODUCTS HAVE BEEN UPDATED. MBS PREV DISCUSSION... /ISSUED 557 AM CST FRI FEB 17 2012/ AVIATION... FOR THE 12Z TAFS...THERE IS QUITE A BIT OF UNCERTAINTY WITH RESPECT TO PRECIPITATION TIMING AND FLIGHT CATEGORIES. AT KAMA...EXPECT MVFR CONDITIONS 13-16Z AS -RA IMPACTS THE TAF SITE. AFTERWARD...VFR MAY PREDOMINANTLY PREVAIL THROUGH 23Z...BUT CONFIDENCE IS LOW. AFTER 23Z...HAVE MODERATE CONFIDENCE THAT MVFR CONDITIONS WILL DEVELOP...DETERIORATING TO IFR AFTER 03Z. AFTER 08Z...LIFR OR VLIFR CONDITIONS WILL BE POSSIBLE...BUT CONFIDENCE IN THIS IS CURRENTLY TOO LOW TO MENTION. AT KDHT...HAVE MODERATE CONFIDENCE THAT VFR CONDITIONS WILL PREVAIL THROUGH 20Z WHEN MVFR CIGS DEVELOP. HAVE MODERATE TO HIGH CONFIDENCE THAT CIGS/VSBYS WILL DETERIORATE INTO IFR CATEGORY AFTER 03Z AND POSSIBLY LIFR/VLIFR AFTER 08Z. HOWEVER...CONFIDENCE IS LOW WHETHER LIFR/VLIFR CONDITIONS WILL DEVELOP. AT KGUY...HAVE MODERATE CONFIDENCE THAT VFR CONDITIONS WILL PREVAIL THROUGH 21Z...BUT THERE IS A POSSIBILITY THAT MVFR CONDITIONS MAY DEVELOP AFTER 21Z. HAVE MODERATE CONFIDENCE THAT MVFR CONDITIONS WILL DEVELOP BY 03Z AND DETERIORATING TO IFR CONDITIONS AFTER 06Z. IT/S POSSIBLE THAT LIFR CONDITIONS COULD DEVELOP AFTER 06Z...BUT CONFIDENCE IN THIS IS LOW. -RA IS EXPECTED AT ALL TAF SITES THROUGH THIS PERIOD...BUT TIMING THE ONSET AND ENDING TIMES AT THIS POINT IS NEARLY IMPOSSIBLE. AMENDMENTS WILL BE NEEDED. IT/S POSSIBLE THERE COULD BE A -RASN MIX AT KDHT AFTER 09Z...BUT CONFIDENCE IS TOO LOW TO MENTION AT THIS TIME. A COLD FRONT WILL MOVE THROUGH ALL SITES 06-08Z WITH WINDS SHIFTING TO THE NORTH. JACKSON PREV DISCUSSION... /ISSUED 448 AM CST FRI FEB 17 2012/ DISCUSSION... PRECIPITATION CHANCES AND TYPES TODAY THROUGH SATURDAY MORNING ARE THE MAIN FORECAST CHALLENGES. LATEST MODELS WERE IN FAIR TO GOOD AGREEMENT. USED A BLEND WITH A PREFERENCE TOWARDS THE 00Z ECMWF DUE TO IT/S BETTER HANDLING OF MOISTURE AND QPF FIELDS. THE BIGGEST CHANGE TO THE PREVIOUS FORECAST WAS TO LOWER PRECIPITATION CHANCES TODAY ACROSS THE NORTH TEXAS AND OKLAHOMA PANHANDLES. AT 445 AM CST ACROSS THE PANHANDLES...MOSTLY CLOUDY CONDITIONS WERE OCCURRING WITH SURFACE TEMPERATURES MAINLY IN THE 30S. LIGHT RAIN SHOWERS WERE NEAR I-40 EAST OF AMARILLO AND AN AREA OF RAIN SHOWERS WERE JUST SOUTH OF A HEREFORD TO CLOVIS LINE. A MID/UPPER LOW WAS WELL SOUTH OF ARIZONA. THIS MORNING...KEPT THE HIGHEST RAIN CHANCES OVER THE SOUTH TEXAS PANHANDLE...GENERALLY 60 TO 90 PERCENT...THINKING CURRENT AREA OF RAIN SHOWERS MENTIONED ABOVE WILL HOLD TOGETHER. THE 00Z ECMWF DID BEST DEPICTING THIS AREA WITH ITS MOISTURE/QPF FIELDS. DOUBT MUCH...IF ANY RAINFALL...WILL OCCUR NORTH OF A CHANNING TO LIPSCOMB LINE. LATEST RUC13 AND WARM LOW LEVEL THERMAL FIELDS SUGGESTED THAT MOST...IF NOT ALL...OF THE PRECIPITATION WILL BE IN THE FORM OF LIGHT RAIN. RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM ZERO IN THE OKLAHOMA PANHANDLE UP TO 0.25 INCH SOUTH OF I-40. THERE IS A LITTLE CONCERN THAT THE PRECIPITATION COULD MIX WITH OR BRIEFLY TURN OVER TO LIGHT SNOW AND BRING A QUICK WET INCH OF SNOWFALL WEST OF I-27 AND SOUTH OF I-40 NEAR HEREFORD THIS MORNING...BUT CONFIDENCE OF THIS OCCURRING SEEMS TO BE QUITE LOW...ESPECIALLY WITH CURRENT SURFACE WET BULB TEMPERATURES A FEW DEGREES ABOVE 32F. THIS AFTERNOON...KEPT RAIN CHANCES...20 TO 50 PERCENT ACROSS THE AREA. THERE MAY BE MORE DRY HOURS THAN WET ONES AND APPEARS ANY ADDITIONAL RAINFALL WILL GENERALLY BE LESS THAN 0.10 INCH. LOW LEVEL TEMPERATURES WILL BE WARM ENOUGH TO SUPPORT ALL RAIN. THE WARMER 00Z MAVMOS HIGHS IN THE 40S APPEARED REASONABLE. TONIGHT INTO SATURDAY MORNING...KEPT PRECIPITATION CHANCES 30 TO 50 PERCENT ACROSS THE AREA TONIGHT...THEN 20 TO 30 PERCENT SATURDAY MORNING. APPEARS ANY PRECIPITATION BEFORE MIDNIGHT WILL BE IN THE FORM OF LIGHT RAIN...THEN TURN OVER TO LIGHT SNOW NORTHWEST TO SOUTHEAST. AT THIS TIME...APPEARS ANY SNOWFALL ACCUMULATIONS WILL BE UNDER ONE HALF INCH. THERE IS A LOW CHANCE A BAND OF SNOW MAY DEVELOP NEAR A DALHART TO BEAVER LINE LATE TONIGHT INTO SATURDAY MORNING WHICH COULD BRING LOCALLY ENHANCE SNOWFALL AND BRING ONE TO TWO INCHES TO THESE AREAS...BUT CONFIDENCE OF THIS OCCURRING SEEMS TO BE VERY LOW...ESPECIALLY AS NOT SURE PHASING WILL OCCUR WITH MID/UPPER TROUGHS MOVING OVER THE AREA. IN ADDITION...APPEARS THE BEST MOISTURE WILL BE CUT OFF AND OVER SOUTH TEXAS. WENT CLOSER TO THE WARMER 00Z MAVMOS LOWS. SATURDAY AFTERNOON THROUGH SUNDAY NIGHT...DRY CONDITIONS ARE EXPECTED. CLOUDS WILL BE SLOW TO CLEAR SATURDAY AFTERNOON...SO LOWERED HIGHS CLOSER TO THE COLDER 00Z MAVMOS NUMBERS. THERE IS A LOW CHANCE FOR LIGHT FREEZING FOG SUNDAY MORNING...BUT DID NOT MENTION DUE TO LOW CONFIDENCE. BREEZY AND WARMER CONDITIONS WILL RETURN SUNDAY AFTERNOON UNDER MOSTLY SUNNY SKIES. MONDAY INTO MONDAY NIGHT...WINDY CONDITIONS SEEM LIKELY...ESPECIALLY MONDAY AFTERNOON. MAY BE CLOSE TO ADVISORY LEVEL OF 35 MPH SUSTAINED FOR 3 OR MORE HOURS. KEPT A DRY FORECAST FOR NOW AS APPEARS THE BEST MOISTURE AND LIFT WILL STAY NORTH AND EAST OF THE AREA. WENT NEAR OR ABOVE THE WARMER 00Z MEXMOS HIGHS. A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE AFTERNOON AND NIGHT. TUESDAY THROUGH THURSDAY...DRY CONDITIONS ARE EXPECTED DURING THIS TIME FRAME. LATEST MODELS WERE IN SOME DISAGREEMENT WITH SURFACE FEATURES. STAYED CLOSE TO THE 00Z MEXMOS TEMPERATURES. MBS FIRE WEATHER... NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED THROUGH THIS WEEKEND. ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE MONDAY AFTERNOON ACROSS MUCH OF THE TEXAS PANHANDLE DUE WINDY CONDITIONS AND LOW HUMIDITY. THERE IS A CHANCE CRITICAL FIRE WEATHER CONDITIONS COULD OCCUR MONDAY AFTERNOON IF GROUND MOISTURE DECREASES SUFFICIENTLY AND ALLOWS FOR VERY LOW HUMIDITY VALUES BELOW 10 PERCENT. WINDY TO PERHAPS VERY WINDY WEST TO SOUTHWEST WINDS MAY OCCUR MONDAY AFTERNOON ALONG WITH A WIND SHIFT DUE TO AN APPROACHING COLD FRONT LATE MONDAY AFTERNOON AND NIGHT. MBS && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 03/16
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
735 AM CST FRI FEB 17 2012 .UPDATE... ADDED SLIGHT CHANCE OF SNOW SHOWERS BETWEEN 9 AM AND NOON CST TODAY ON THE CAPROCK MAINLY ALONG AND SOUTH OF I-40 INCLUDING AMARILLO... CANYON...HEREFORD...VEGA...PANHANDLE...CLAUDE...AND PAMPA. && .DISCUSSION... LIGHT PRECIPITATION...MAINLY IN THE FORM OF LIGHT RAIN...CONTINUES TO MOVE NORTHEAST AND INTO THE SOUTH TEXAS PANHANDLE THIS MORNING. MADE THE ADJUSTMENTS ABOVE AS LATEST KLBB RADAR INDICATED BRIGHT BANDING AS LOW AS 600 FT AGL JUST NORTHWEST OF LUBBOCK. APPEARS THIS HEAVIER ACTIVITY MAY COOL THE LOWEST 5000 FT OF THE ATMOSPHERE ENOUGH TO ALLOW FOR LIGHT SNOW TO MIX WITH THE LIGHT RAIN ACROSS THE SOUTH CENTRAL AND SOUTHWEST TEXAS PANHANDLES BETWEEN 9 AM AND NOON CST INCLUDING AMARILLO. WITH WARM SURFACE TEMPERATURES ABOVE FREEZING/32 DEGREES...IF ANY SNOW OCCURS...NO ACCUMULATIONS ARE EXPECTED. STILL BELIEVE LIGHT RAIN WILL BE THE PREDOMINANT PRECIPITATION TYPE THIS MORNING. SOME MID/UPPER DRY SLOTTING MOVING INTO THE PANHANDLES MAY LIMIT PRECIPITATION CHANCES THIS AFTERNOON. BY MIDDAY TODAY...SURFACE TEMPERATURES WILL LIKELY BE TOO WARM TO SUPPORT ANYTHING BUT LIGHT RAIN. PRODUCTS HAVE BEEN UPDATED. MBS && .PREV DISCUSSION... /ISSUED 557 AM CST FRI FEB 17 2012/ AVIATION... FOR THE 12Z TAFS...THERE IS QUITE A BIT OF UNCERTAINTY WITH RESPECT TO PRECIPITATION TIMING AND FLIGHT CATEGORIES. AT KAMA...EXPECT MVFR CONDITIONS 13-16Z AS -RA IMPACTS THE TAF SITE. AFTERWARD...VFR MAY PREDOMINANTLY PREVAIL THROUGH 23Z...BUT CONFIDENCE IS LOW. AFTER 23Z...HAVE MODERATE CONFIDENCE THAT MVFR CONDITIONS WILL DEVELOP...DETERIORATING TO IFR AFTER 03Z. AFTER 08Z...LIFR OR VLIFR CONDITIONS WILL BE POSSIBLE...BUT CONFIDENCE IN THIS IS CURRENTLY TOO LOW TO MENTION. AT KDHT...HAVE MODERATE CONFIDENCE THAT VFR CONDITIONS WILL PREVAIL THROUGH 20Z WHEN MVFR CIGS DEVELOP. HAVE MODERATE TO HIGH CONFIDENCE THAT CIGS/VSBYS WILL DETERIORATE INTO IFR CATEGORY AFTER 03Z AND POSSIBLY LIFR/VLIFR AFTER 08Z. HOWEVER...CONFIDENCE IS LOW WHETHER LIFR/VLIFR CONDITIONS WILL DEVELOP. AT KGUY...HAVE MODERATE CONFIDENCE THAT VFR CONDITIONS WILL PREVAIL THROUGH 21Z...BUT THERE IS A POSSIBILITY THAT MVFR CONDITIONS MAY DEVELOP AFTER 21Z. HAVE MODERATE CONFIDENCE THAT MVFR CONDITIONS WILL DEVELOP BY 03Z AND DETERIORATING TO IFR CONDITIONS AFTER 06Z. IT/S POSSIBLE THAT LIFR CONDITIONS COULD DEVELOP AFTER 06Z...BUT CONFIDENCE IN THIS IS LOW. -RA IS EXPECTED AT ALL TAF SITES THROUGH THIS PERIOD...BUT TIMING THE ONSET AND ENDING TIMES AT THIS POINT IS NEARLY IMPOSSIBLE. AMENDMENTS WILL BE NEEDED. IT/S POSSIBLE THERE COULD BE A -RASN MIX AT KDHT AFTER 09Z...BUT CONFIDENCE IS TOO LOW TO MENTION AT THIS TIME. A COLD FRONT WILL MOVE THROUGH ALL SITES 06-08Z WITH WINDS SHIFTING TO THE NORTH. JACKSON PREV DISCUSSION... /ISSUED 448 AM CST FRI FEB 17 2012/ DISCUSSION... PRECIPITATION CHANCES AND TYPES TODAY THROUGH SATURDAY MORNING ARE THE MAIN FORECAST CHALLENGES. LATEST MODELS WERE IN FAIR TO GOOD AGREEMENT. USED A BLEND WITH A PREFERENCE TOWARDS THE 00Z ECMWF DUE TO IT/S BETTER HANDLING OF MOISTURE AND QPF FIELDS. THE BIGGEST CHANGE TO THE PREVIOUS FORECAST WAS TO LOWER PRECIPITATION CHANCES TODAY ACROSS THE NORTH TEXAS AND OKLAHOMA PANHANDLES. AT 445 AM CST ACROSS THE PANHANDLES...MOSTLY CLOUDY CONDITIONS WERE OCCURRING WITH SURFACE TEMPERATURES MAINLY IN THE 30S. LIGHT RAIN SHOWERS WERE NEAR I-40 EAST OF AMARILLO AND AN AREA OF RAIN SHOWERS WERE JUST SOUTH OF A HEREFORD TO CLOVIS LINE. A MID/UPPER LOW WAS WELL SOUTH OF ARIZONA. THIS MORNING...KEPT THE HIGHEST RAIN CHANCES OVER THE SOUTH TEXAS PANHANDLE...GENERALLY 60 TO 90 PERCENT...THINKING CURRENT AREA OF RAIN SHOWERS MENTIONED ABOVE WILL HOLD TOGETHER. THE 00Z ECMWF DID BEST DEPICTING THIS AREA WITH ITS MOISTURE/QPF FIELDS. DOUBT MUCH...IF ANY RAINFALL...WILL OCCUR NORTH OF A CHANNING TO LIPSCOMB LINE. LATEST RUC13 AND WARM LOW LEVEL THERMAL FIELDS SUGGESTED THAT MOST...IF NOT ALL...OF THE PRECIPITATION WILL BE IN THE FORM OF LIGHT RAIN. RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM ZERO IN THE OKLAHOMA PANHANDLE UP TO 0.25 INCH SOUTH OF I-40. THERE IS A LITTLE CONCERN THAT THE PRECIPITATION COULD MIX WITH OR BRIEFLY TURN OVER TO LIGHT SNOW AND BRING A QUICK WET INCH OF SNOWFALL WEST OF I-27 AND SOUTH OF I-40 NEAR HEREFORD THIS MORNING...BUT CONFIDENCE OF THIS OCCURRING SEEMS TO BE QUITE LOW...ESPECIALLY WITH CURRENT SURFACE WET BULB TEMPERATURES A FEW DEGREES ABOVE 32F. THIS AFTERNOON...KEPT RAIN CHANCES...20 TO 50 PERCENT ACROSS THE AREA. THERE MAY BE MORE DRY HOURS THAN WET ONES AND APPEARS ANY ADDITIONAL RAINFALL WILL GENERALLY BE LESS THAN 0.10 INCH. LOW LEVEL TEMPERATURES WILL BE WARM ENOUGH TO SUPPORT ALL RAIN. THE WARMER 00Z MAVMOS HIGHS IN THE 40S APPEARED REASONABLE. TONIGHT INTO SATURDAY MORNING...KEPT PRECIPITATION CHANCES 30 TO 50 PERCENT ACROSS THE AREA TONIGHT...THEN 20 TO 30 PERCENT SATURDAY MORNING. APPEARS ANY PRECIPITATION BEFORE MIDNIGHT WILL BE IN THE FORM OF LIGHT RAIN...THEN TURN OVER TO LIGHT SNOW NORTHWEST TO SOUTHEAST. AT THIS TIME...APPEARS ANY SNOWFALL ACCUMULATIONS WILL BE UNDER ONE HALF INCH. THERE IS A LOW CHANCE A BAND OF SNOW MAY DEVELOP NEAR A DALHART TO BEAVER LINE LATE TONIGHT INTO SATURDAY MORNING WHICH COULD BRING LOCALLY ENHANCE SNOWFALL AND BRING ONE TO TWO INCHES TO THESE AREAS...BUT CONFIDENCE OF THIS OCCURRING SEEMS TO BE VERY LOW...ESPECIALLY AS NOT SURE PHASING WILL OCCUR WITH MID/UPPER TROUGHS MOVING OVER THE AREA. IN ADDITION...APPEARS THE BEST MOISTURE WILL BE CUT OFF AND OVER SOUTH TEXAS. WENT CLOSER TO THE WARMER 00Z MAVMOS LOWS. SATURDAY AFTERNOON THROUGH SUNDAY NIGHT...DRY CONDITIONS ARE EXPECTED. CLOUDS WILL BE SLOW TO CLEAR SATURDAY AFTERNOON...SO LOWERED HIGHS CLOSER TO THE COLDER 00Z MAVMOS NUMBERS. THERE IS A LOW CHANCE FOR LIGHT FREEZING FOG SUNDAY MORNING...BUT DID NOT MENTION DUE TO LOW CONFIDENCE. BREEZY AND WARMER CONDITIONS WILL RETURN SUNDAY AFTERNOON UNDER MOSTLY SUNNY SKIES. MONDAY INTO MONDAY NIGHT...WINDY CONDITIONS SEEM LIKELY...ESPECIALLY MONDAY AFTERNOON. MAY BE CLOSE TO ADVISORY LEVEL OF 35 MPH SUSTAINED FOR 3 OR MORE HOURS. KEPT A DRY FORECAST FOR NOW AS APPEARS THE BEST MOISTURE AND LIFT WILL STAY NORTH AND EAST OF THE AREA. WENT NEAR OR ABOVE THE WARMER 00Z MEXMOS HIGHS. A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE AFTERNOON AND NIGHT. TUESDAY THROUGH THURSDAY...DRY CONDITIONS ARE EXPECTED DURING THIS TIME FRAME. LATEST MODELS WERE IN SOME DISAGREEMENT WITH SURFACE FEATURES. STAYED CLOSE TO THE 00Z MEXMOS TEMPERATURES. MBS FIRE WEATHER... NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED THROUGH THIS WEEKEND. ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE MONDAY AFTERNOON ACROSS MUCH OF THE TEXAS PANHANDLE DUE WINDY CONDITIONS AND LOW HUMIDITY. THERE IS A CHANCE CRITICAL FIRE WEATHER CONDITIONS COULD OCCUR MONDAY AFTERNOON IF GROUND MOISTURE DECREASES SUFFICIENTLY AND ALLOWS FOR VERY LOW HUMIDITY VALUES BELOW 10 PERCENT. WINDY TO PERHAPS VERY WINDY WEST TO SOUTHWEST WINDS MAY OCCUR MONDAY AFTERNOON ALONG WITH A WIND SHIFT DUE TO AN APPROACHING COLD FRONT LATE MONDAY AFTERNOON AND NIGHT. MBS && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 13/17
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
557 AM CST FRI FEB 17 2012 .AVIATION... FOR THE 12Z TAFS...THERE IS QUITE A BIT OF UNCERTAINTY WITH RESPECT TO PRECIPITATION TIMING AND FLIGHT CATEGORIES. AT KAMA...EXPECT MVFR CONDITIONS 13-16Z AS -RA IMPACTS THE TAF SITE. AFTERWARD...VFR MAY PREDOMINANTLY PREVAIL THROUGH 23Z...BUT CONFIDENCE IS LOW. AFTER 23Z...HAVE MODERATE CONFIDENCE THAT MVFR CONDITIONS WILL DEVELOP...DETERIORATING TO IFR AFTER 03Z. AFTER 08Z...LIFR OR VLIFR CONDITIONS WILL BE POSSIBLE...BUT CONFIDENCE IN THIS IS CURRENTLY TOO LOW TO MENTION. AT KDHT...HAVE MODERATE CONFIDENCE THAT VFR CONDITIONS WILL PREVAIL THROUGH 20Z WHEN MVFR CIGS DEVELOP. HAVE MODERATE TO HIGH CONFIDENCE THAT CIGS/VSBYS WILL DETERIORATE INTO IFR CATEGORY AFTER 03Z AND POSSIBLY LIFR/VLIFR AFTER 08Z. HOWEVER...CONFIDENCE IS LOW WHETHER LIFR/VLIFR CONDITIONS WILL DEVELOP. AT KGUY...HAVE MODERATE CONFIDENCE THAT VFR CONDITIONS WILL PREVAIL THROUGH 21Z...BUT THERE IS A POSSIBILITY THAT MVFR CONDITIONS MAY DEVELOP AFTER 21Z. HAVE MODERATE CONFIDENCE THAT MVFR CONDITIONS WILL DEVELOP BY 03Z AND DETERIORATING TO IFR CONDITIONS AFTER 06Z. IT/S POSSIBLE THAT LIFR CONDITIONS COULD DEVELOP AFTER 06Z...BUT CONFIDENCE IN THIS IS LOW. -RA IS EXPECTED AT ALL TAF SITES THROUGH THIS PERIOD...BUT TIMING THE ONSET AND ENDING TIMES AT THIS POINT IS NEARLY IMPOSSIBLE. AMENDMENTS WILL BE NEEDED. IT/S POSSIBLE THERE COULD BE A -RASN MIX AT KDHT AFTER 09Z...BUT CONFIDENCE IS TOO LOW TO MENTION AT THIS TIME. A COLD FRONT WILL MOVE THROUGH ALL SITES 06-08Z WITH WINDS SHIFTING TO THE NORTH. JACKSON && .PREV DISCUSSION... /ISSUED 448 AM CST FRI FEB 17 2012/ DISCUSSION... PRECIPITATION CHANCES AND TYPES TODAY THROUGH SATURDAY MORNING ARE THE MAIN FORECAST CHALLENGES. LATEST MODELS WERE IN FAIR TO GOOD AGREEMENT. USED A BLEND WITH A PREFERENCE TOWARDS THE 00Z ECMWF DUE TO IT/S BETTER HANDLING OF MOISTURE AND QPF FIELDS. THE BIGGEST CHANGE TO THE PREVIOUS FORECAST WAS TO LOWER PRECIPITATION CHANCES TODAY ACROSS THE NORTH TEXAS AND OKLAHOMA PANHANDLES. AT 445 AM CST ACROSS THE PANHANDLES...MOSTLY CLOUDY CONDITIONS WERE OCCURRING WITH SURFACE TEMPERATURES MAINLY IN THE 30S. LIGHT RAIN SHOWERS WERE NEAR I-40 EAST OF AMARILLO AND AN AREA OF RAIN SHOWERS WERE JUST SOUTH OF A HEREFORD TO CLOVIS LINE. A MID/UPPER LOW WAS WELL SOUTH OF ARIZONA. THIS MORNING...KEPT THE HIGHEST RAIN CHANCES OVER THE SOUTH TEXAS PANHANDLE...GENERALLY 60 TO 90 PERCENT...THINKING CURRENT AREA OF RAIN SHOWERS MENTIONED ABOVE WILL HOLD TOGETHER. THE 00Z ECMWF DID BEST DEPICTING THIS AREA WITH ITS MOISTURE/QPF FIELDS. DOUBT MUCH...IF ANY RAINFALL...WILL OCCUR NORTH OF A CHANNING TO LIPSCOMB LINE. LATEST RUC13 AND WARM LOW LEVEL THERMAL FIELDS SUGGESTED THAT MOST...IF NOT ALL...OF THE PRECIPITATION WILL BE IN THE FORM OF LIGHT RAIN. RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM ZERO IN THE OKLAHOMA PANHANDLE UP TO 0.25 INCH SOUTH OF I-40. THERE IS A LITTLE CONCERN THAT THE PRECIPITATION COULD MIX WITH OR BRIEFLY TURN OVER TO LIGHT SNOW AND BRING A QUICK WET INCH OF SNOWFALL WEST OF I-27 AND SOUTH OF I-40 NEAR HEREFORD THIS MORNING...BUT CONFIDENCE OF THIS OCCURRING SEEMS TO BE QUITE LOW...ESPECIALLY WITH CURRENT SURFACE WET BULB TEMPERATURES A FEW DEGREES ABOVE 32F. THIS AFTERNOON...KEPT RAIN CHANCES...20 TO 50 PERCENT ACROSS THE AREA. THERE MAY BE MORE DRY HOURS THAN WET ONES AND APPEARS ANY ADDITIONAL RAINFALL WILL GENERALLY BE LESS THAN 0.10 INCH. LOW LEVEL TEMPERATURES WILL BE WARM ENOUGH TO SUPPORT ALL RAIN. THE WARMER 00Z MAVMOS HIGHS IN THE 40S APPEARED REASONABLE. TONIGHT INTO SATURDAY MORNING...KEPT PRECIPITATION CHANCES 30 TO 50 PERCENT ACROSS THE AREA TONIGHT...THEN 20 TO 30 PERCENT SATURDAY MORNING. APPEARS ANY PRECIPITATION BEFORE MIDNIGHT WILL BE IN THE FORM OF LIGHT RAIN...THEN TURN OVER TO LIGHT SNOW NORTHWEST TO SOUTHEAST. AT THIS TIME...APPEARS ANY SNOWFALL ACCUMULATIONS WILL BE UNDER ONE HALF INCH. THERE IS A LOW CHANCE A BAND OF SNOW MAY DEVELOP NEAR A DALHART TO BEAVER LINE LATE TONIGHT INTO SATURDAY MORNING WHICH COULD BRING LOCALLY ENHANCE SNOWFALL AND BRING ONE TO TWO INCHES TO THESE AREAS...BUT CONFIDENCE OF THIS OCCURRING SEEMS TO BE VERY LOW...ESPECIALLY AS NOT SURE PHASING WILL OCCUR WITH MID/UPPER TROUGHS MOVING OVER THE AREA. IN ADDITION...APPEARS THE BEST MOISTURE WILL BE CUT OFF AND OVER SOUTH TEXAS. WENT CLOSER TO THE WARMER 00Z MAVMOS LOWS. SATURDAY AFTERNOON THROUGH SUNDAY NIGHT...DRY CONDITIONS ARE EXPECTED. CLOUDS WILL BE SLOW TO CLEAR SATURDAY AFTERNOON...SO LOWERED HIGHS CLOSER TO THE COLDER 00Z MAVMOS NUMBERS. THERE IS A LOW CHANCE FOR LIGHT FREEZING FOG SUNDAY MORNING...BUT DID NOT MENTION DUE TO LOW CONFIDENCE. BREEZY AND WARMER CONDITIONS WILL RETURN SUNDAY AFTERNOON UNDER MOSTLY SUNNY SKIES. MONDAY INTO MONDAY NIGHT...WINDY CONDITIONS SEEM LIKELY...ESPECIALLY MONDAY AFTERNOON. MAY BE CLOSE TO ADVISORY LEVEL OF 35 MPH SUSTAINED FOR 3 OR MORE HOURS. KEPT A DRY FORECAST FOR NOW AS APPEARS THE BEST MOISTURE AND LIFT WILL STAY NORTH AND EAST OF THE AREA. WENT NEAR OR ABOVE THE WARMER 00Z MEXMOS HIGHS. A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE AFTERNOON AND NIGHT. TUESDAY THROUGH THURSDAY...DRY CONDITIONS ARE EXPECTED DURING THIS TIME FRAME. LATEST MODELS WERE IN SOME DISAGREEMENT WITH SURFACE FEATURES. STAYED CLOSE TO THE 00Z MEXMOS TEMPERATURES. MBS FIRE WEATHER... NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED THROUGH THIS WEEKEND. ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE MONDAY AFTERNOON ACROSS MUCH OF THE TEXAS PANHANDLE DUE WINDY CONDITIONS AND LOW HUMIDITY. THERE IS A CHANCE CRITICAL FIRE WEATHER CONDITIONS COULD OCCUR MONDAY AFTERNOON IF GROUND MOISTURE DECREASES SUFFICIENTLY AND ALLOWS FOR VERY LOW HUMIDITY VALUES BELOW 10 PERCENT. WINDY TO PERHAPS VERY WINDY WEST TO SOUTHWEST WINDS MAY OCCUR MONDAY AFTERNOON ALONG WITH A WIND SHIFT DUE TO AN APPROACHING COLD FRONT LATE MONDAY AFTERNOON AND NIGHT. MBS && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ JJ/MBS
AREA FORECAST DISCUSSION
NWS AMARILLO TX
448 AM CST FRI FEB 17 2012 .DISCUSSION... PRECIPITATION CHANCES AND TYPES TODAY THROUGH SATURDAY MORNING ARE THE MAIN FORECAST CHALLENGES. LATEST MODELS WERE IN FAIR TO GOOD AGREEMENT. USED A BLEND WITH A PREFERENCE TOWARDS THE 00Z ECMWF DUE TO IT/S BETTER HANDLING OF MOISTURE AND QPF FIELDS. THE BIGGEST CHANGE TO THE PREVIOUS FORECAST WAS TO LOWER PRECIPITATION CHANCES TODAY ACROSS THE NORTH TEXAS AND OKLAHOMA PANHANDLES. AT 445 AM CST ACROSS THE PANHANDLES...MOSTLY CLOUDY CONDITIONS WERE OCCURRING WITH SURFACE TEMPERATURES MAINLY IN THE 30S. LIGHT RAIN SHOWERS WERE NEAR I-40 EAST OF AMARILLO AND AN AREA OF RAIN SHOWERS WERE JUST SOUTH OF A HEREFORD TO CLOVIS LINE. A MID/UPPER LOW WAS WELL SOUTH OF ARIZONA. THIS MORNING...KEPT THE HIGHEST RAIN CHANCES OVER THE SOUTH TEXAS PANHANDLE...GENERALLY 60 TO 90 PERCENT...THINKING CURRENT AREA OF RAIN SHOWERS MENTIONED ABOVE WILL HOLD TOGETHER. THE 00Z ECMWF DID BEST DEPICTING THIS AREA WITH ITS MOISTURE/QPF FIELDS. DOUBT MUCH...IF ANY RAINFALL...WILL OCCUR NORTH OF A CHANNING TO LIPSCOMB LINE. LATEST RUC13 AND WARM LOW LEVEL THERMAL FIELDS SUGGESTED THAT MOST...IF NOT ALL...OF THE PRECIPITATION WILL BE IN THE FORM OF LIGHT RAIN. RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM ZERO IN THE OKLAHOMA PANHANDLE UP TO 0.25 INCH SOUTH OF I-40. THERE IS A LITTLE CONCERN THAT THE PRECIPITATION COULD MIX WITH OR BRIEFLY TURN OVER TO LIGHT SNOW AND BRING A QUICK WET INCH OF SNOWFALL WEST OF I-27 AND SOUTH OF I-40 NEAR HEREFORD THIS MORNING...BUT CONFIDENCE OF THIS OCCURRING SEEMS TO BE QUITE LOW...ESPECIALLY WITH CURRENT SURFACE WET BULB TEMPERATURES A FEW DEGREES ABOVE 32F. THIS AFTERNOON...KEPT RAIN CHANCES...20 TO 50 PERCENT ACROSS THE AREA. THERE MAY BE MORE DRY HOURS THAN WET ONES AND APPEARS ANY ADDITIONAL RAINFALL WILL GENERALLY BE LESS THAN 0.10 INCH. LOW LEVEL TEMPERATURES WILL BE WARM ENOUGH TO SUPPORT ALL RAIN. THE WARMER 00Z MAVMOS HIGHS IN THE 40S APPEARED REASONABLE. TONIGHT INTO SATURDAY MORNING...KEPT PRECIPITATION CHANCES 30 TO 50 PERCENT ACROSS THE AREA TONIGHT...THEN 20 TO 30 PERCENT SATURDAY MORNING. APPEARS ANY PRECIPITATION BEFORE MIDNIGHT WILL BE IN THE FORM OF LIGHT RAIN...THEN TURN OVER TO LIGHT SNOW NORTHWEST TO SOUTHEAST. AT THIS TIME...APPEARS ANY SNOWFALL ACCUMULATIONS WILL BE UNDER ONE HALF INCH. THERE IS A LOW CHANCE A BAND OF SNOW MAY DEVELOP NEAR A DALHART TO BEAVER LINE LATE TONIGHT INTO SATURDAY MORNING WHICH COULD BRING LOCALLY ENHANCE SNOWFALL AND BRING ONE TO TWO INCHES TO THESE AREAS...BUT CONFIDENCE OF THIS OCCURRING SEEMS TO BE VERY LOW...ESPECIALLY AS NOT SURE PHASING WILL OCCUR WITH MID/UPPER TROUGHS MOVING OVER THE AREA. IN ADDITION...APPEARS THE BEST MOISTURE WILL BE CUT OFF AND OVER SOUTH TEXAS. WENT CLOSER TO THE WARMER 00Z MAVMOS LOWS. SATURDAY AFTERNOON THROUGH SUNDAY NIGHT...DRY CONDITIONS ARE EXPECTED. CLOUDS WILL BE SLOW TO CLEAR SATURDAY AFTERNOON...SO LOWERED HIGHS CLOSER TO THE COLDER 00Z MAVMOS NUMBERS. THERE IS A LOW CHANCE FOR LIGHT FREEZING FOG SUNDAY MORNING...BUT DID NOT MENTION DUE TO LOW CONFIDENCE. BREEZY AND WARMER CONDITIONS WILL RETURN SUNDAY AFTERNOON UNDER MOSTLY SUNNY SKIES. MONDAY INTO MONDAY NIGHT...WINDY CONDITIONS SEEM LIKELY...ESPECIALLY MONDAY AFTERNOON. MAY BE CLOSE TO ADVISORY LEVEL OF 35 MPH SUSTAINED FOR 3 OR MORE HOURS. KEPT A DRY FORECAST FOR NOW AS APPEARS THE BEST MOISTURE AND LIFT WILL STAY NORTH AND EAST OF THE AREA. WENT NEAR OR ABOVE THE WARMER 00Z MEXMOS HIGHS. A COLD FRONT IS EXPECTED TO MOVE THROUGH THE AREA LATE AFTERNOON AND NIGHT. TUESDAY THROUGH THURSDAY...DRY CONDITIONS ARE EXPECTED DURING THIS TIME FRAME. LATEST MODELS WERE IN SOME DISAGREEMENT WITH SURFACE FEATURES. STAYED CLOSE TO THE 00Z MEXMOS TEMPERATURES. MBS && .FIRE WEATHER... NO ELEVATED OR CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED THROUGH THIS WEEKEND. ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE MONDAY AFTERNOON ACROSS MUCH OF THE TEXAS PANHANDLE DUE WINDY CONDITIONS AND LOW HUMIDITY. THERE IS A CHANCE CRITICAL FIRE WEATHER CONDITIONS COULD OCCUR MONDAY AFTERNOON IF GROUND MOISTURE DECREASES SUFFICIENTLY AND ALLOWS FOR VERY LOW HUMIDITY VALUES BELOW 10 PERCENT. WINDY TO PERHAPS VERY WINDY WEST TO SOUTHWEST WINDS MAY OCCUR MONDAY AFTERNOON ALONG WITH A WIND SHIFT DUE TO AN APPROACHING COLD FRONT LATE MONDAY AFTERNOON AND NIGHT. MBS && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 44 32 39 25 56 / 80 40 20 0 0 BEAVER OK 51 31 41 24 52 / 30 50 30 0 0 BOISE CITY OK 48 27 41 21 55 / 20 40 20 0 0 BORGER TX 45 32 41 28 56 / 60 40 20 0 0 BOYS RANCH TX 44 29 39 26 57 / 70 50 20 0 0 CANYON TX 44 31 40 24 56 / 90 40 20 0 0 CLARENDON TX 45 35 44 27 56 / 90 40 30 0 0 DALHART TX 45 28 40 21 57 / 40 50 20 0 0 GUYMON OK 48 29 44 23 54 / 30 50 20 0 0 HEREFORD TX 43 30 43 25 57 / 90 40 20 0 0 LIPSCOMB TX 47 34 41 22 53 / 40 50 30 0 0 PAMPA TX 46 33 41 24 53 / 70 40 30 0 0 SHAMROCK TX 49 36 42 25 54 / 80 40 30 0 0 WELLINGTON TX 49 37 45 27 54 / 80 40 30 0 0 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 13/17
AREA FORECAST DISCUSSION
NWS SPOKANE WA
255 PM PST Fri Feb 17 2012 .SYNOPSIS... A strong weather system will pass through the region tonight and early Saturday resulting in widespread rain and snow to the valleys and snow to the mountains. Snow showers will continue to impact the region through the day Saturday...lingering across the Idaho Panhandle through Sunday afternoon. The active weather pattern is expected to continue through much of the upcoming week. && .DISCUSSION... Tonight: Low pressure continues to spin off the northern tip of Vancouver Island, with an occluded/cold front trailing southward along the Washington and Oregon coastline. Satellite and radar shows this feature steadily moving inland. A swath of precipitation was expanding across western Washington and coming into the Cascades around 22Z (near 2 PM PST). Extrapolation of the shield brings precipitation across the Cascades near 00Z and near the Idaho border toward 05-06Z, with the potential for areas of light precipitation developing ahead of the main swath. The forecast for tonight follows this general trend, meaning a good chance of precipitation in most areas. The duration, however, may not be long in some spots especially once occluded/cold front passage occurs. Extrapolation based on satellite brings the front east of the Cascades between 06-08Z and east of the Washington/Idaho border between 12-14Z. Thus the precipitation should begin to wane overnight in the lee of the Cascades, including areas such as Wenatchee and Moses Lake and toward morning toward the Idaho border with increasing south to southwest winds. Temperatures have been slow to warm over the west and northern portions of the CWA, but there remains good opportunity for warming this evening ahead of the front. Even the most recent guidance, including the 20Z RUC and 18Z NAM, show temperatures warming and accompanying wet-bulb zero heights rising toward 3-5kft across the Moses Lake area, Columbia Basin east into the Spokane/C`da area and Palouse and south into the Blues/L-C Valley. This will mean a threat of rain and snow or perhaps all snow that will have little success in accumulating. The periphery of the CWA will see lower snow levels, near 1-3kft, with a much better chance of accumulating snows. Winter weather highlights remain in place for most of these snows, including the Cascades and northern mountains, and the Wenatchee area through Okanogan Valley. In this latter region, areas below 1500-2500 feet will likely remain on the lower end of advisory amounts. The Idaho Panhandle mountain zones are also under winter weather highlights, starting late tonight. Some of the higher accumulations are expected near the crest of the Cascades and closer to the Canadian border. /J. Cote` Saturday through Monday: The winter storm expected to bring snow and rain to the region this evening and overnight will continue to have a large influence on the weekend weather. The strong frontal occlusion will be just lifting out of Idaho early Saturday morning and the cold core upper-level trough will be in the process of settling into the Inland NW. 500mb temperatures will be cooling near -34C along the WA/ID border to -30C along the Cascades leading to increasing atmospheric instability...and likelihood for snow showers throughout the afternoon and evening across most locations. There are a few features that will impact the order of events. First of all, a midlevel dry slot will be in place roughly 12-18z Saturday which will prevent the ongoing orographic showers for N WA and N ID from producing excessive amounts of QPF/snow due as the brief drying is noted within the heart of the dendritic layer (-10 to -20 celsius). On another note, these showers should persist as strong SW to NE pressure gradients setup across the region bringing gusty winds for most lowlands south of highway 2 and east of the Waterville Plateau. Wind sustained at 15-25 mph with gusts on the order of 30-40 mph will be possible...especially along the typical windy locations within the Blue Mountains and adjacent foothills and lower Columbia Basin, Palouse, and West Plains. This strong upsloping component will continue to fuel the orographic showers despite the drying aloft. As midlevels slowly re-saturate throughout the day, the threat for moderate to heavy mountain snow showers will increase. Snow showers for the valleys will be more hit or miss Saturday afternoon until the remnants of the low pressure system nearing the northern tip of Vancouver Island tracks across the region. Aside from weak differential PVA (positive vorticity advection), there are signs of incr warm advection processes with this feature as the higher theta-e air within its occluded core track through. As a result, the threat for light to locally moderate valley and mtn snows will amp back up Saturday evening through Sunday morning. For several days, the models have shown a track roughly from Seattle to Missoula which favors locations along and north of highway 2 for a secondary light snow event during this time. The forecast has been updated to reflect these changes which will has led to an extension of the winter wx advisories for ID until Saturday afternoon. The storm system will finally clear east of the region Sunday night with a break in the pcpn for most locations. Another wave dropping within the northwesterly jet will bring another shot of light pcpn (mainly snow) for Monday. There is still quite a bit of uncertainty with the strength of this wave and forecast trends were toward the drier SREF/GFS at this time. If skies are able to clear completely Sunday night, we could be looking at very cold temperatures for the northern valleys...however clouds should be on the increase as the next wave of moisture drops into BC and we took a more conservative approach to overnight lows. /sb Monday night through Friday...Models in fair agreement with the overall synoptic scale pattern this period. Longwave ridge is expected to set up along 140w or so and remain there through much of the week. This places the Inland NW under somewhat moist northwest flow. While this pattern isn`t terribly conducive to heavy precipitation...various weak shortwaves passing over the top of the ridge will deliver periods of light precipitation...especially to locations near the Cascade Crest and over the Idaho Panhandle. The air mass associated with this pattern is not very unstable and thus...we should see a well-defined rain shadow in the lee of the Cascades due to persistent westerly mid-level flow over the crest. The pattern could also prove to be a windy one...especially on Wednesday as a strong surface low crosses central portions of British Columbia and Alberta. The 18z GFS solution shows surface winds over the southern Columbia Basin and Washington Palouse of 25-30kt with 850 mb winds ranging from 35-45 kts. If this were to verify...we would certainly need a wind advisory. However the 12z ECMWF and 12z GFS Ensembles don`t paint quite as windy of a picture. Anyway...even if its not quite as windy as the GFS suggests...it will certainly be windier than the weather we have seen for much of this week...which should equate to fairly mild daytime temperatures. Most valleys south of I90 will highs in the 40s through much of the week...with 50s expected over southern portions of the Palouse, Columbia Basin...and Lewiston area. The longwave ridge axis is expected to shift slightly eastward on Friday and then amplify significantly for the following weekend. The change on Friday could be accompanied by a fairly vigorous shortwave trough crossing through the southern half of British Columbia which could deliver a good chance of precipitation to the northern half of our forecast area. Then again there is quite a difference between this solution and the one offered by ECMWF which depicts a much weaker disturbance. By next weekend there is good model consistency that the offshore ridge will amplify into Alaska with deep northerly flow pushing into the western US. 850 mb temps would plunge as a result...with temperatures possibly falling much below the seasonal normals and certainly colder than what we have seen in quite sometime. fx && .AVIATION... 00Z TAFS: All sites will start this period with VFR to MVFR conditions. As the next system approaches, expect conditions to quickly diminish from the West to East. Ceilings and visibilities will be IFR for brief periods for all sites as the system passes through their respective areas. Expect periods of rain/snow showers at the northern and higher elevation sites. Conditions will be back to VFR conditions in the West by end of the TAF period. / JDC && .PRELIMINARY POINT TEMPS/POPS... Spokane 33 37 28 37 27 36 / 100 60 60 20 10 30 Coeur d`Alene 31 37 28 36 27 36 / 100 70 70 20 20 30 Pullman 33 39 29 37 28 38 / 100 50 70 30 10 30 Lewiston 36 45 32 43 30 45 / 80 40 40 20 10 20 Colville 30 39 20 38 23 35 / 100 70 70 20 20 30 Sandpoint 30 36 27 36 25 36 / 100 80 70 30 20 30 Kellogg 30 36 27 35 26 35 / 100 90 80 60 20 40 Moses Lake 33 45 26 44 27 41 / 100 20 20 10 10 20 Wenatchee 30 40 27 41 26 38 / 100 30 20 10 10 20 Omak 29 37 19 37 21 37 / 100 70 20 10 10 20 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...Winter Weather Advisory from 10 PM this evening to 10 AM PST Sunday for Central Panhandle Mountains-Northern Panhandle. WA...Winter Weather Advisory until 4 AM PST Saturday for Okanogan Highlands-Okanogan Valley-Waterville Plateau-Wenatchee Area. Winter Weather Advisory until 4 PM PST Saturday for East Slopes Northern Cascades. Winter Storm Warning from 10 PM this evening to 4 PM PST Saturday for Northeast Mountains. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1110 AM CST FRI FEB 17 2012 .SHORT TERM... 305 AM CST FRI FEB 17 2012 MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TODAY. 07Z WATER VAPOR IMAGERY SHOWS SHORTWAVE TROUGH OVER NORTH DAKOTA. AT THE SURFACE...A WEAK COLD FRONT WAS SITUATED FROM NORTHERN MINNESOTA...BACK INTO EASTERN SOUTH DAKOTA. BAND OF MAINLY MID LEVEL CLOUDS WERE SEEN AHEAD OF IT ACROSS MINNESOTA. 17.00Z MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD. SHORTWAVE OVER NORTH DAKOTA WILL ROTATE SOUTHEAST AND ACROSS THE FORECAST AREA TODAY...AS SURFACE COLD FRONT AND WEAK SURFACE LOW PUSHES THROUGH THE AREA. BOTH THE GFS AND NAM SHOWING A SWATH OF QG CONVERGENCE BETWEEN 850MB-500MB ALONG WITH SOME 285K-295K ISENTROPIC LIFT. IN ADDITION...850MB-700MB LAPSE RATES RATHER STEEP 7-9 DEGREES CELSIUS PER KILOMETER BY THIS AFTERNOON. RUC ALSO SHOWING UPWARDS OF 200 J/KG OF 0-3KM MOST UNSTABLE CAPE OVER THE NORTHEASTERN PORTION OF THE FORECAST AREA. THE BIGGEST QUESTION WILL BE DEGREE OF SATURATION. 17.06Z RUC BUFKIT SOUNDINGS SHOWS BEST SATURATION TO THE NORTH OF INTERSTATE 94...WITH AREAS SOUTH OF THERE SATURATION OCCURS ABOVE 900MB. DID RAISE PROBABILITIES A LITTLE ACROSS THE NORTHEAST. WITH MILD PACIFIC AIRMASS IN PLACE AND SURFACE TEMPERATURES EXPECTED INTO THE MIDDLE 30S TO THE LOWER 40S DID MENTION BOTH RAIN AND SNOW SHOWERS. SHORTWAVE EXITS EAST OF THE AREA TONIGHT WITH ONLY SOME LINGERING PRECIPITATION EARLY IN THE EVENING ACROSS THE EASTERN COUNTIES. OTHERWISE...BOTH THE NAM AND GFS INDICATE SOME STRATUS BEHIND THE FONT TO SETTLE OVER THE AREA...MAINLY ACROSS THE NORTHEAST SECTIONS OF THE FORECAST AREA. THESE CLOUDS WILL MOVE OUT RATHER QUICKLY ON SATURDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA. THIS SURFACE HIGH WILL REMAIN OVERHEAD THROUGH SUNDAY WITH CLEAR SKIES...LIGHT WINDS AND SEASONABLE TEMPERATURES. .LONG TERM... 305 AM CST FRI FEB 17 2012 BOTH THE 17.00Z GFS AND ECMWF SHOWING A MORE ACTIVE WEATHER PATTERN DURING THIS TIME FRAME. LONGWAVE TROUGH PUSHES OUT OF THE CENTRAL CONUS MONDAY AND ACROSS THE AREA MONDAY NIGHT INTO TUESDAY. GFS IS SHOWING A MORE NORTH/SOUTH SPLIT OF THE ENERGY VERSUS THE ECMWF...ALTHOUGH THE ECMWF TO A LESSER EXTENT IS ALSO SHOWING THIS TREND. THUS...SURFACE LOW LOOKS TO BE SOMEWHAT WEAKER. GULF WILL BE OPEN AHEAD OF THE SYSTEM WHICH WILL ALLOW FOR A GOOD FETCH OF MOISTURE AHEAD OF IT. WITH PACIFIC AIRMASS REMAINING IN PLACE QUESTION WILL BE PRECIPITATION TYPES...WITH A LIKELY SCENARIO OF MAINLY SNOW MONDAY NIGHT AND RAIN/SNOW TUESDAY. ANOTHER WAVE DROPS THROUGH THE AREA WEDNESDAY THROUGH THURSDAY AND KEPT PRECIPITATION CHANCES IN THE FORECAST WITH RAIN/SNOW MIX. ALL IN ALL...TEMPERATURES LOOK TO REMAIN MILD AND ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION... 1110 AM CST FRI FEB 17 2012 COLD FRONT SWEEPING WEST TO EAST ACROSS THE REGION THIS AFTERNOON. SUNSHINE INITIALLY POST FRONT...SO LOOK FOR SOME GUSTINESS WITH MIXING. MAIN CONCERNS FOCUS ON AN AREA OF MVFR TO VFR CIGS SINKING SOUTH ACROSS NORTHERN/CENTRAL MN. LATEST RUC13/NAM12 RH FIELDS FAVOR BRINGING THESE CLOUDS OVER KRST/KLSE...WITH PROBABILITIES HIGHER FROM THE MISSISSIPPI RIVER EAST. LITTLE IF ANY -SN ASSOCIATED WITH THESE CLOUDS...AND DON/T EXPECT ANY -SN THAT COULD IMPACT VSBYS AT THIS TIME. THE CLOUDS SHOULD EXIT EAST OVERNIGHT AS AN AREA OF HIGH PRESSURE BUILDS IN FROM THE PLAINS. LOOK FOR VFR CONDITIONS THROUGH THE REST OF THE WEEKEND...WITH NORTHWEST WINDS BECOMING SOUTHERLY ON SUNDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... 305 AM CST FRI FEB 17 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RABERDING LONG TERM....RABERDING AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
546 AM CST FRI FEB 17 2012 .SHORT TERM... 305 AM CST FRI FEB 17 2012 MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TODAY. 07Z WATER VAPOR IMAGERY SHOWS SHORTWAVE TROUGH OVER NORTH DAKOTA. AT THE SURFACE...A WEAK COLD FRONT WAS SITUATED FROM NORTHERN MINNESOTA...BACK INTO EASTERN SOUTH DAKOTA. BAND OF MAINLY MID LEVEL CLOUDS WERE SEEN AHEAD OF IT ACROSS MINNESOTA. 17.00Z MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD. SHORTWAVE OVER NORTH DAKOTA WILL ROTATE SOUTHEAST AND ACROSS THE FORECAST AREA TODAY...AS SURFACE COLD FRONT AND WEAK SURFACE LOW PUSHES THROUGH THE AREA. BOTH THE GFS AND NAM SHOWING A SWATH OF QG CONVERGENCE BETWEEN 850MB-500MB ALONG WITH SOME 285K-295K ISENTROPIC LIFT. IN ADDITION...850MB-700MB LAPSE RATES RATHER STEEP 7-9 DEGREES CELSIUS PER KILOMETER BY THIS AFTERNOON. RUC ALSO SHOWING UPWARDS OF 200 J/KG OF 0-3KM MOST UNSTABLE CAPE OVER THE NORTHEASTERN PORTION OF THE FORECAST AREA. THE BIGGEST QUESTION WILL BE DEGREE OF SATURATION. 17.06Z RUC BUFKIT SOUNDINGS SHOWS BEST SATURATION TO THE NORTH OF INTERSTATE 94...WITH AREAS SOUTH OF THERE SATURATION OCCURS ABOVE 900MB. DID RAISE PROBABILITIES A LITTLE ACROSS THE NORTHEAST. WITH MILD PACIFIC AIRMASS IN PLACE AND SURFACE TEMPERATURES EXPECTED INTO THE MIDDLE 30S TO THE LOWER 40S DID MENTION BOTH RAIN AND SNOW SHOWERS. SHORTWAVE EXITS EAST OF THE AREA TONIGHT WITH ONLY SOME LINGERING PRECIPITATION EARLY IN THE EVENING ACROSS THE EASTERN COUNTIES. OTHERWISE...BOTH THE NAM AND GFS INDICATE SOME STRATUS BEHIND THE FONT TO SETTLE OVER THE AREA...MAINLY ACROSS THE NORTHEAST SECTIONS OF THE FORECAST AREA. THESE CLOUDS WILL MOVE OUT RATHER QUICKLY ON SATURDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA. THIS SURFACE HIGH WILL REMAIN OVERHEAD THROUGH SUNDAY WITH CLEAR SKIES...LIGHT WINDS AND SEASONABLE TEMPERATURES. .LONG TERM... 305 AM CST FRI FEB 17 2012 BOTH THE 17.00Z GFS AND ECMWF SHOWING A MORE ACTIVE WEATHER PATTERN DURING THIS TIME FRAME. LONGWAVE TROUGH PUSHES OUT OF THE CENTRAL CONUS MONDAY AND ACROSS THE AREA MONDAY NIGHT INTO TUESDAY. GFS IS SHOWING A MORE NORTH/SOUTH SPLIT OF THE ENERGY VERSUS THE ECMWF...ALTHOUGH THE ECMWF TO A LESSER EXTENT IS ALSO SHOWING THIS TREND. THUS...SURFACE LOW LOOKS TO BE SOMEWHAT WEAKER. GULF WILL BE OPEN AHEAD OF THE SYSTEM WHICH WILL ALLOW FOR A GOOD FETCH OF MOISTURE AHEAD OF IT. WITH PACIFIC AIRMASS REMAINING IN PLACE QUESTION WILL BE PRECIPITATION TYPES...WITH A LIKELY SCENARIO OF MAINLY SNOW MONDAY NIGHT AND RAIN/SNOW TUESDAY. ANOTHER WAVE DROPS THROUGH THE AREA WEDNESDAY THROUGH THURSDAY AND KEPT PRECIPITATION CHANCES IN THE FORECAST WITH RAIN/SNOW MIX. ALL IN ALL...TEMPERATURES LOOK TO REMAIN MILD AND ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION...TODAY AND TONIGHT 546 AM CST FRI FEB 17 2012 WILL BE WATCHING A WEAK AREA OF LOW PRESSURE AND COLD FRONT MOVE ACROSS THE AREA TODAY. MOST OF THE LIFT AND THREAT FOR ANY PRECIPITATION ASSOCIATED WITH THIS SYSTEM APPEARS TO BE THIS MORNING. A BRIEF SNOW SHOWER PASSED THROUGH KONA AROUND 1058Z WHICH DROPPED THE VISIBILITY BRIEFLY TO AROUND A MILE. THIS SNOW SHOWER THREAT APPEARS TO LINGER THROUGH THIS MORNING MAINLY ALONG/EAST OF THE MISSISSIPPI RIVER. BASED ON THIS...HAVE OPTED TO KEEP VCSH IN THE KLSE THROUGH THIS MORNING. OTHERWISE...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THIS MORNING. LOOK FOR THE COLD FRONT TO PASS THROUGH KRST AROUND 18Z AND AT KLSE BY 21Z...WHICH WILL SWING THE WINDS TO THE NORTHWEST WITH SOME GUSTINESS INTO THE 15 TO 20KT RANGE. GFS/NAM MODELS THEN SHOW SOME LOWER LEVEL MOISTURE/MVFR CLOUD ROTATING INTO THE AREA THIS AFTERNOON BEHIND THE FRONT...LINGERING INTO THE OVERNIGHT HOURS. THE BULK OF THIS CLOUD APPEARS TO BE CONFINED ALONG AND EAST OF THE MISSISSIPPI RIVER. AS A RESULT...KEPT KRST VFR WHILE KLSE WILL LIKELY GO TO MVFR BY 01Z. && .ARX WATCHES/WARNINGS/ADVISORIES... 305 AM CST FRI FEB 17 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RABERDING LONG TERM...RABERDING AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
305 AM CST FRI FEB 17 2012 .SHORT TERM... 305 AM CST FRI FEB 17 2012 MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TODAY. 07Z WATER VAPOR IMAGERY SHOWS SHORTWAVE TROUGH OVER NORTH DAKOTA. AT THE SURFACE...A WEAK COLD FRONT WAS SITUATED FROM NORTHERN MINNESOTA...BACK INTO EASTERN SOUTH DAKOTA. BAND OF MAINLY MID LEVEL CLOUDS WERE SEEN AHEAD OF IT ACROSS MINNESOTA. 17.00Z MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD. SHORTWAVE OVER NORTH DAKOTA WILL ROTATE SOUTHEAST AND ACROSS THE FORECAST AREA TODAY...AS SURFACE COLD FRONT AND WEAK SURFACE LOW PUSHES THROUGH THE AREA. BOTH THE GFS AND NAM SHOWING A SWATH OF QG CONVERGENCE BETWEEN 850MB-500MB ALONG WITH SOME 285K-295K ISENTROPIC LIFT. IN ADDITION...850MB-700MB LAPSE RATES RATHER STEEP 7-9 DEGREES CELSIUS PER KILOMETER BY THIS AFTERNOON. RUC ALSO SHOWING UPWARDS OF 200 J/KG OF 0-3KM MOST UNSTABLE CAPE OVER THE NORTHEASTERN PORTION OF THE FORECAST AREA. THE BIGGEST QUESTION WILL BE DEGREE OF SATURATION. 17.06Z RUC BUFKIT SOUNDINGS SHOWS BEST SATURATION TO THE NORTH OF INTERSTATE 94...WITH AREAS SOUTH OF THERE SATURATION OCCURS ABOVE 900MB. DID RAISE PROBABILITIES A LITTLE ACROSS THE NORTHEAST. WITH MILD PACIFIC AIRMASS IN PLACE AND SURFACE TEMPERATURES EXPECTED INTO THE MIDDLE 30S TO THE LOWER 40S DID MENTION BOTH RAIN AND SNOW SHOWERS. SHORTWAVE EXITS EAST OF THE AREA TONIGHT WITH ONLY SOME LINGERING PRECIPITATION EARLY IN THE EVENING ACROSS THE EASTERN COUNTIES. OTHERWISE...BOTH THE NAM AND GFS INDICATE SOME STRATUS BEHIND THE FONT TO SETTLE OVER THE AREA...MAINLY ACROSS THE NORTHEAST SECTIONS OF THE FORECAST AREA. THESE CLOUDS WILL MOVE OUT RATHER QUICKLY ON SATURDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA. THIS SURFACE HIGH WILL REMAIN OVERHEAD THROUGH SUNDAY WITH CLEAR SKIES...LIGHT WINDS AND SEASONABLE TEMPERATURES. .LONG TERM... 305 AM CST FRI FEB 17 2012 BOTH THE 17.00Z GFS AND ECMWF SHOWING A MORE ACTIVE WEATHER PATTERN DURING THIS TIME FRAME. LONGWAVE TROUGH PUSHES OUT OF THE CENTRAL CONUS MONDAY AND ACROSS THE AREA MONDAY NIGHT INTO TUESDAY. GFS IS SHOWING A MORE NORTH/SOUTH SPLIT OF THE ENERGY VERSUS THE ECMWF...ALTHOUGH THE ECMWF TO A LESSER EXTENT IS ALSO SHOWING THIS TREND. THUS...SURFACE LOW LOOKS TO BE SOMEWHAT WEAKER. GULF WILL BE OPEN AHEAD OF THE SYSTEM WHICH WILL ALLOW FOR A GOOD FETCH OF MOISTURE AHEAD OF IT. WITH PACIFIC AIRMASS REMAINING IN PLACE QUESTION WILL BE PRECIPITATION TYPES...WITH A LIKELY SCENARIO OF MAINLY SNOW MONDAY NIGHT AND RAIN/SNOW TUESDAY. ANOTHER WAVE DROPS THROUGH THE AREA WEDNESDAY THROUGH THURSDAY AND KEPT PRECIPITATION CHANCES IN THE FORECAST WITH RAIN/SNOW MIX. ALL IN ALL...TEMPERATURES LOOK TO REMAIN MILD AND ABOVE NORMAL THROUGH THE PERIOD. && .AVIATION...THROUGH 06Z SATURDAY 1131 PM CST THU FEB 16 2012 SURFACE HIGH PRESSURE RIDGE AXIS IS PASSING OVER THE AREA LATE THIS EVENING AND A WEAK AREA OF LOW PRESSURE WAS NEAR KFAR. A BAND OF MID LEVEL CLOUDS WITH VFR CEILINGS WAS ADVANCING SOUTHEAST AHEAD OF THE SURFACE LOW AND IS EXPECTED TO SPREAD ACROSS BOTH TAF SITES BEFORE 12Z. THE SURFACE LOW IS EXPECTED TO TRACK ACROSS CENTRAL MINNESOTA AND WISCONSIN THROUGH TONIGHT AND FRIDAY AS A SHORT WAVE TROUGH ALOFT MOVES ACROSS THE UPPER MIDWEST. THE BEST FORCING FROM THE SHORT WAVE TROUGH IS EXPECTED TO OCCUR DURING THE LATE MORNING HOURS WITH THE 17.00Z NAM BEING THE STRONGEST AND BRINGS IN A SHORT PERIOD OF MVFR CEILINGS A BOTH TAF SITES. THE 17.03Z RUC ALSO SHOWS THESE CEILINGS DEVELOPING WHILE THE 17.00Z GFS DOES NOT AND THE PROBABILITIES FOR MVFR CEILINGS FROM THE 16.21Z SREF IS ONLY AROUND 20. THIS SIGNAL HAS BEEN CONSISTENT IN THE NAM SO HAVE INTRODUCED A SHORT PERIOD OF SOME TEMPORARY MVFR CEILINGS FOR BOTH SITES LATE FRIDAY MORNING. ONCE THE WEAK LOW GOES BY...THE WINDS WILL SWING AROUND TO THE NORTHWEST WITH ALL GUIDANCE SHOWING THE CLOUDS SCATTERING OUT. && .ARX WATCHES/WARNINGS/ADVISORIES... 305 AM CST FRI FEB 17 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RABERDING LONG TERM...RABERDING AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1132 PM CST THU FEB 16 2012 .SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT 239 PM CST THU FEB 16 2012 MAIN FORECAST CONCERNS THIS PACKAGE...SMALL SPRINKLE/FLURRY CHANCE ON FRI...CLOUDS/TEMPERAURES THRU THE PERIOD. DATA ANALYSIS AT 18Z HAD A BROAD AREA OF HIGH PRESSURE OVER MUCH OF THE CENTRAL CONUS...CENTERED OVER KS/OK. A WEAK LOW WAS LOCATED NORTH OF LK SUPERIOR...PRODUCING WEST TO NORTHWEST GRADIENT FLOW AND WEAK LOW LEVEL COLD ADVECTION ACROSS MUCH OF MN/IA/WI AT MID DAY. A SHORTWAVE WAS MOVING ACROSS NORTHERN WI. BUT FOR A PATCH OF MID CLOUDS MOVING ACROSS CENTRAL WI...CLOUDS AND ANY PRECIP WITH THE SHORTWAVE CONFINED TO FAR NORTHERN MN/WI. ELSEWHERE SUNNY SKIES AND MINIMAL SNOW COVER OVER MUCH OF MN/IA/WI ALLOWING NOON-TIME TEMPS TO AGAIN WARM INTO THE 30S TO LOW 40S OVER MUCH OF THE REGION. 16.12Z MODELS LOOK TO HAVE INITIALIZED WELL AND OFFER QUITE SIMILAR SOLUTIONS FOR TONIGHT INTO SUN NIGHT. BIGGEST DIFFERENCE OF SIGNIFICANCE LOOKS TO BE 925-850MB MOISTURE/SATURATION AND IMPACTS ON ANY PRECIP CHANCE FRI. DPROG/DT OF 500MB HGTS AT 16.12Z SHOWED MODEL RUNS OF 14.12Z AND 15.12Z VERIFIED QUITE WELL ACROSS NOAM WITH A TIGHT CONSENSUS TRENDED TOWARD A COMPROMISE OF THE EARLIER RUNS ON ALL FEATURES. TREND FOR TONIGHT/FRI IS TOWARD THE MORE PROGRESSIVE OF EARLIER RUNS WITH THE SHORTWAVE TROUGH DROPPING INTO THE UPPER MIDWEST. THIS FASTER TREND FAVORED FRI NIGHT/SAT AS THE TROUGH SHIFTS EAST OF THE AREA AND HGTS RISE ACROSS THE NORTHERN PLAINS. BETTER CONSISTENCY DEVELOPING SAT THRU SUN NIGHT WITH THE NEXT TROUGH INTO THE WESTERN CONUS SAT THEN INTO THE ROCKIES/WESTERN PLAINS SUN/SUN NIGHT...AND CONTINUED RISING HGTS/RIDGING ALOFT OVER THE UPPER MIDWEST. CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED ALL MODELS QUITE GOOD WITH THE SFC MASS FIELDS OVER CENTRAL NOAM. PER WV IMAGERY...ALL MODELS LOOKED QUITE GOOD WITH THE SHORTWAVE DETAILS ACROSS NOAM. WITH NO PREFERRED DETERMINISTIC MODEL AT 18Z AND THE TREND TOWARD A TIGHTER COMMON SOLUTION...FAVORED THE MODEL/ ENSEMBLE CONSENSUS THIS CYCLE. SHORT-TERM FCST CONFIDENCE GOOD... THOUGH THE SHORT-TERM REMAINS RATHER QUIET FOR THE AREA. FOR THE SHORT TERM...BUT FOR FRI THE SHORT TERM IS GENERALLY DOMINATED BY HIGH PRESSURE AND MODIFIED PACIFIC AIRMASSES. MID/HIGH CLOUDS INCREASE TONIGHT AHEAD OF THE SHORTWAVE APPROACHING ACROSS ND/MN...WITH LOWER CLOUDS/MOISTURE SWEEPING ACROSS MUCH OF THE AREA BEHIND THE DEPARTING SFC-850MB TROUGH FRI NIGHT. RIDGING ALOFT...SFC HIGH PRESSURE...LOW LEVEL ANTICYCLONIC FLOW/SUBSIDENCE/DIVERGENCE SPREAD ACROSS THE AREA FOR SAT THRU SUN NIGHT. GENERALLY CLEAR TO PARTLY CLOUDY SKIES AND LIGHT WINDS EXPECTED SAT THRU SUN NIGHT UNDER THE INFLUENCE OF THE HIGH/RIDGING ALOFT. LOW LEVEL COLD ADVECTION SPREADS ACROSS THE AREA IN THE WAKE OF THE TROUGH FRI NIGHT...WITH 925MB TEMPS FOR SAT IN THE -6C TO -10C RANGE AND HIGHS SAT CLOSER TO NORMAL FOR MID FEB. WITH LIGHT WINDS UNDER THE SFC- 850MB RIDGE AXIS SAT NIGHT INTO SUN NIGHT...AIRMASS ONLY SLOWLY MODIFIES/WARMS. WITH PLENTY OF SUNSHINE BY SUN AND MINIMAL SNOW COVER...HIGHS SUN SHOULD BE AT LEAST A FEW DEGREES WARMER THAN THOSE OF SAT. BACK TO FRI/FRI EVENING...MODEL CONSENSUS CONTINUES TO INDICATE MAIN MOISTURE WITH THE APPROACHING/PASSING SHORTWAVE WILL BE ABOVE ABOUT 800MB. BULK OF LOWER LEVEL CONVERGENCE/LIFT AHEAD OF THE SFC-700MB TROUGH AND DIVERGENCE ALOFT AHEAD OF THE MID LEVEL SHORTWAVE STILL APPEAR TO GO INTO TRYING TO SATURATE THE COLUMN ENOUGH TO ALLOW ANY PRECIP TO REACH THE GROUND. PER MODEL SOUNDINGS AND X-SECTIONS...BY THE TIME SOME 925-800MB SATURATION OCCURS THE STRONGER/DEEPER OF THE LIFT IS PASSING EAST OF THE FCST AREA LATE FRI AFTERNOON/ EVENING. GIVEN THE INITIAL DRY AIRMASS OVER THE AREA AND MINIMAL CLOUDS OVER ND WITH/AHEAD OF THE SHORTWAVE THIS AFTERNOON...REDUCED PRECIP MENTION FRI/FRI EVENING TO SPRINKLES/FLURRIES WITH A SMALL CHANCE OF MEASURABLE PRECIPITATION. MOISTURE CENTERED NEAR 925MB ROTATES SOUTHEAST ACROSS THE AREA BEHIND THE TROUGH FRI NIGHT BUT THIS QUITE SHALLOW UNDER A DEVELOPING INVERSION NEAR 900MB. WITH THE PROGRESSIVENESS OF THE SFC-MID LEVEL TROUGH AND RIDGING BUILDING IN THIS MOISTURE/STRATUS EXPECTED TO PUSH EAST OF THE FCST AREA BY OR DURING SAT MORNING. NUMERICAL TEMP GUIDANCE FOR TONIGHT THRU SUN NIGHT QUITE SIMILAR AND LOOK TO BE IN THE BALLPARK. WITH PLENTY OF SUNSHINE EXPECTED SAT/SUN AND MINIMAL/BROKEN SNOW COVER...TRENDED HIGHS BOTH DAYS TOWARD THE WARMER OF GUIDANCE HIGHS. .LONG TERM...MONDAY THROUGH THURSDAY 239 PM CST THU FEB 16 2012 16.00Z MEDIUM RANGE MODEL RUNS CONTINUE THE TREND OF THE 15.12Z RUNS OF A MORE NORTH/SOUTH STREAM SPLIT OF THE ENERGY IN THE TROUGH MOVING ACROSS THE CENTRAL CONUS MON/TUE. NORTHERN STREAM PORTION OF THE TROUGH REMAINS MORE PROGRESSIVE...WITH A POSITIVE TILT TO THE TROUGH AS IT MOVES ACROSS THE UPPER MIDWEST TUE. BETTER BETWEEN MODEL CONSISTENCY WED FOR A NORTHERN STREAM SHORTWAVE TO CARVE OUT A LONG-WAVE TROUGH OVER THE NORTH-CENTRAL CONUS. MODELS THEN DIFFER ON THE PROGRESSIVENESS OF THIS TROUGH BY THU...GFS FASTER...ECMWF SLOWER. THE TRENDS MON/TUE LEAD TO LESSER RUN-TO-RUN CONSISTENCY AND LOWER FCST CONFIDENCE. GFS/ECMWF DO OFFER DECENT RUN-TO-RUN CONSISTENCY WITH THEIR OWN PREVIOUS RUNS WED/THU. THE 16.12Z GFS/ ECMWF RUNS CONTINUE TO SUPPORT THIS. WITH ALL THE SPREAD IN THE DETAILS...LESSER BETWEEN MODEL AND RUN-TO-RUN CONSISTENCY...LIKE PMDEPD A MODEL/ENSEMBLE BLEND FAVORED IN THE DAY 4-7 PERIOD. LONG- TERM FCST CONFIDENCE AVERAGE AT BEST. PATTERN DOES LOOK TO BE MORE ACTIVE/UNSETTLED NEXT WEEK WITH AREA TO BE IMPACTED BY 2 STRONGER TROUGHS. FIRST TROUGH MOVES INTO THE CENTRAL/NORTHERN PLAINS MON WITH SHORTWAVE RIDGING ALOFT AND MILD HIGH PRESSURE SLOWLY SHIFTING EAST OF THE AREA. THE SFC THRU MID LEVEL TROUGH WITH AN INCREASE OF MOISTURE AND FORCING/LIFT MOVES INTO/ACROSS THE UPPER MIDWEST MON NIGHT/TUE. SOME TIMING/SPEED DIFFERENCES AMONG THE MODELS BY DAYS 4/5 BUT MAINLY -SN CHANCES IN THE 25-45 PERCENT RANGE REASONABLE FOR NOW. PLENTY OF DETAIL DIFFERENCES BY WED/THU...BUT ANOTHER INCREASE OF MOISTURE/LIFT WITH FALLING HGTS AS THE NEXT NORTHERN STREAM SHORTWAVE CARVES OUT A DEEPER TROUGH ACROSS THE UPPER MIDWEST. PRECIP CHANCES IN THE 15-30 PERCENT RANGE FOR WED/THU REASONABLE UNTIL MODELS CONVERGE ON A TIGHTER CONSENSUS SOLUTION. LOWER LEVELS ABOVE 0C WED...WITH COLUMN COOLING THRU WED NIGHT/THU AS HGTS FALL. PRECIP WOULD BE -RA OR -RA/-SN WED...TRANSITIONING TO MAINLY -SN FOR WED NIGHT/THU. WITH UNCERTAINTIES ON CLOUDS/PRECIP...A BLEND OF THE NUMERICAL GUIDANCE HIGHS/LOWS FOR MON-THU REASONABLE FOR NOW. && .AVIATION...THROUGH 06Z SATURDAY 1131 PM CST THU FEB 16 2012 SURFACE HIGH PRESSURE RIDGE AXIS IS PASSING OVER THE AREA LATE THIS EVENING AND A WEAK AREA OF LOW PRESSURE WAS NEAR KFAR. A BAND OF MID LEVEL CLOUDS WITH VFR CEILINGS WAS ADVANCING SOUTHEAST AHEAD OF THE SURFACE LOW AND IS EXPECTED TO SPREAD ACROSS BOTH TAF SITES BEFORE 12Z. THE SURFACE LOW IS EXPECTED TO TRACK ACROSS CENTRAL MINNESOTA AND WISCONSIN THROUGH TONIGHT AND FRIDAY AS A SHORT WAVE TROUGH ALOFT MOVES ACROSS THE UPPER MIDWEST. THE BEST FORCING FROM THE SHORT WAVE TROUGH IS EXPECTED TO OCCUR DURING THE LATE MORNING HOURS WITH THE 17.00Z NAM BEING THE STRONGEST AND BRINGS IN A SHORT PERIOD OF MVFR CEILINGS A BOTH TAF SITES. THE 17.03Z RUC ALSO SHOWS THESE CEILINGS DEVELOPING WHILE THE 17.00Z GFS DOES NOT AND THE PROBABILITIES FOR MVFR CEILINGS FROM THE 16.21Z SREF IS ONLY AROUND 20. THIS SIGNAL HAS BEEN CONSISTENT IN THE NAM SO HAVE INTRODUCED A SHORT PERIOD OF SOME TEMPORARY MVFR CEILINGS FOR BOTH SITES LATE FRIDAY MORNING. ONCE THE WEAK LOW GOES BY...THE WINDS WILL SWING AROUND TO THE NORTHWEST WITH ALL GUIDANCE SHOWING THE CLOUDS SCATTERING OUT. && .ARX WATCHES/WARNINGS/ADVISORIES... 239 PM CST THU FEB 16 2012 WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RRS LONG TERM....RRS AVIATION...04
AREA FORECAST DISCUSSION
NWS TOPEKA KS
346 AM CST SUN FEB 19 2012 .DISCUSSION... SHORT RANGE FORECAST (TODAY AND MONDAY)... EARLY MORNING 11 TO 3.9 MICRON SATELLITE IMAGERY INDICATES THAT ALL OF NORTHEAST KANSAS REMAINS UNDER MOSTLY CLEAR SKIES. 08Z WATER VAPOR IMAGERY AND THE ASSOCIATED RUC UPPER AIR ANALYSIS SHOWS A WEAK UPPER TROUGH MOVING EASTWARD INTO NORTHERN MISSOURI. THIS TROUGH WILL NOT HAVE MUCH AFFECT ON THE REGION THIS MORNING AS IT EXITS TO THE EAST. ALSO TO THE WEST...THE NEXT UPPER WAVE IS BEGINNING TO DIG INTO THE INTERIOR WESTERN US AND SHOULD BE CROSSING THE GREAT DIVIDE ON SUNDAY NIGHT. THIS WESTERN TROUGH WILL BE THE ONE TO WATCH AS WE HEAD INTO NEXT WEEK. BETWEEN THE TWO UPPER TROUGHS IS A SHORTWAVE RIDGE WHICH WILL MOVE OVER THE AREA FOR SUNDAY. SOUTHERLY WINDS WILL PICK UP THROUGHOUT THE DAY ON SUNDAY...WHICH IN COMBINATION WITH THE UPPER RIDGE SHOULD ALLOW TEMPS TO WARM UP A BIT FROM SATURDAY. EXPECT TEMPS TO RISE INTO THE LOWER 50S TODAY AS THE LOWER ATMOSPHERE SHOULD BE ABLE TO MIX TO AROUND 850 MB ON SUNDAY. SOUTHERLY WINDS WILL PERSIST THROUGH THE NIGHT AS THE SURFACE WAVE DEEPENS AS IT COMES OFF THE HIGH PLAINS. THE LASTING SOUTHERLY FETCH SHOULD ALLOW DECENT MOISTURE (FOR THIS TIME OF YEAR) TO RETURN INTO THE CENTRAL PLAINS. MODELS FOR A COUPLE DAYS HAVE HINTED AT LOWER TO MID 40 DEWPOINTS REACHING INTO NORTHEAST KANSAS IN ADVANCE OF THE NEXT TROUGH. TAKING A CUE FROM THE 00Z AND 06Z NAM HAVE INTRODUCED SOME THUNDER TO THE GOING FORECAST AS MODELS HAVE NOW INDICATED ENOUGH MOISTURE INFLUX AND STEEP ENOUGH MID LEVEL LAPSE RATES TO GENERATE UP TO 500-700 J/KG OF MUCAPE DURING THE DAY ON MONDAY. WITH THAT MUCH INSTABILITY IT SEEMS ALMOST LIKELY AT THIS POINT THAT THUNDERSTORMS WILL BE EMBEDDED WITHIN THE MONDAY RAIN SHIELD. ONCE THE MAIN UPPER WAVE ENTERS THE CENTRAL PLAINS ON MONDAY AFTERNOON/EVENING IT WOULD PROVIDE ENOUGH LIFT TO KICK OFF RAIN SHOWERS ACROSS THE ENTIRE FORECAST AREA. SURFACE AND LOW LEVEL WINDS SHOULD BE BACKED ON MONDAY AFTERNOON WHICH IN CONJUNCTION WITH S-SWLY FLOW IN THE LOW TO MID LEVELS WILL ALLOW FOR SOME TURNING IN THE ATMOSPHERE. WITH 0-6 SHEAR EXPECTED TO BE ON THE ORDER OF 40 TO 50 KNOTS...THE COMBINATION OF INSTABILITY WITH SHEAR MAY ALLOW FOR SOME ISOLATED STRONG THUNDERSTORMS WHICH WOULD ALSO BRING AN ISOLATED HAIL THREAT FOR MONDAY. ONCE THE SUN SETS ON MONDAY NIGHT THE INSTABILITY SHOULD WANE RAPIDLY...SO ANY LINGERING SHOWERS BEYOND 8 PM TO 9 PM ON MONDAY SHOULD BE LIGHT STRATIFORM RAIN AS OPPOSED TO THUNDERSTORMS. EXPECT PRECIP TO EXIT THE AREA COMPLETELY BY AROUND MIDNIGHT ON TUESDAY MORNING. MID RANGE AND EXTENDED FORECAST (TUESDAY THROUGH SATURDAY)... A RATHER MILD AND UNSEASONABLY WARM WEEK IS ON TAP ONCE THE RAIN SHOWERS EXIT ON TUESDAY MORNING. A RATHER PRONOUNCED DOWN SLOPE COMPONENT TO THE WINDS PRESENTS ITSELF FOR TUESDAY AND WEDNESDAY WHICH SHOULD AID IN WARMING TEMPS FOR THE MID TO LATE WEEK TIME PERIOD. BROAD UPPER WAVE THEN SLIDES SOUTHEASTWARD LATE IN THE WEEK...WHICH WILL BRING AN ISOLATED CHANCE FOR SOME PRECIP IN THE FAR NORTHEASTERN CORNER OF THE STATE. SURFACE HIGH THEN DROPS SOUTHWARD ON THURSDAY INTO FRIDAY...WHICH WILL BRING A COOLING TREND FOR THE LATE HALF OF THE WEEK. SINCE THE AIR MASS DOES NOT LOOK TO BE ARCTIC IN NATURE EXPECT TEMPERATURES TO REMAIN AT OR SLIGHTLY ABOVE SEASONAL NORMALS. JL && .AVIATION... VFR CONDITIONS ARE FORECAST THROUGH THE TAF WITH LIGHT WINDS OVERNIGHT TURNING OUT OF THE SOUTHEAST AT UP TO 12 KTS ON SUNDAY. BARJENBRUCH && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1232 AM EST SUN FEB 19 2012 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 342 PM EST SAT FEB 18 2012 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER THE UPR GRT LKS BTWN TROF CENTERED OVER QUEBEC AND A RDG ACRS WCNTRL CAN. SHRTWV EMBEDDED WITHIN THIS FLOW IS OVER LOWER MI AND DIGGING SEWD...LEAVING THE CWA UNDER VIGOROUS DNVA/UPR CNVGC/00Z-12Z H3 RISES AOA 100M IN ITS WAKE. ASSOCIATED SFC HI PRE RDG EXTENDS FM NW ONTARIO INTO MN. DESPITE THE VIGOROUS SUBSIDENCE ASSOCIATED WITH THESE DYNAMICS...PLENTY OF LO CLDS LINGER NOT ONLY OVER UPR MI IN THE CHILLY LLVL NW FLOW E OF THE INCOMING RDG AXIS BUT ALSO INTO NRN MN RIGHT UNDER THE RDG AXIS. IN FACT...THE 12Z INL/YPL RAOBS DEPICT A STRONG SUBSIDENCE INVRN. HOWEVER SINCE THE INVRN BASE IS SURPRISINGLY HI H85-875...THERE IS AMPLE DEPTH FOR LLVL MIXING WITH INVERTED V SUB-INVRN LYR. SINCE H85 TEMPS ARE STILL ARND -15C IN THE LLVL THERMAL TROF TRAILING THE DEPARTING SHRTWV...LES PERSISTS MAINLY IN THE NW SN BELTS. BUT THE INTENSITY OF THIS ACTIVITY IS DIMINISHING WITH FAIRLY HI SFC DEWPT DEPRESSIONS AND THE FLOW TENDING TOWARD MORE ACYC UNDER THE NEGATIVE DYNAMICS. FARTHER UPSTREAM...THERE IS A SHRTWV NEAR LK WINNIPEG MOVING ESEWD. BUT THE AIRMASS IS SO DRY IN THIS AREA NOTHING BUT HI CLDS MARK THE PRESENCE OF THIS FEATURE. MAIN FCST CONCERNS THRU SUN ARE CLD TRENDS TNGT/IMPACT ON TEMPS. TNGT...AS HI PRES BUILDS SLOWLY ACRS WI/UPR MI TNGT UNDER CONFLUENT WNW FLOW ALF AND THE FLOW BACKS MORE TO THE W...EXPECT LINGERING LES TO SHIFT INTO AREAS FAVORED BY THAT FLOW AND DIMINISH. WITH THE BACKING FLOW...SUSPECT THE BULK OF THE LO CLD IN NRN MN WILL DRIFT TO THE N OF UPR MI AS SHOWN BY THE 12Z LOCAL WRF-ARW MODEL. BUT THESE CLDS MAY BE MORE PERSISTENT OVER THE KEWEENAW WITH FAVORABLE UPSLOPE WIND COMPONENT DOWN THE LENGTH OF WRN LK SUP AND E OF MUNISING WITH A LATER BACKING OF THE FLOW. EVEN THOUGH SOME OF THE HI CLDS ASSOCIATED WITH THE DISTURBANCE NEAR LK WINNIPEG MAY DRIFT OVER THE CWA LATER TNGT AS THIS SHRTWV MOVES INTO NRN MN TOWARD 12Z...LGT WINDS/PWAT IN THE 0.15-0.20 INCH RANGE SUPPORT GOING FCST MIN TEMPS TOWARD THE LO END OF GUIDANCE OVER AT LEAST THE INTERIOR W HALF. SUN...AS THE SFC HI PRES RDG DRIFTS INTO LOWER MI...THE LLVL FLOW OVER UPR MI WL SHIFT TO THE SW...SO ANY LINGERING LK CLDS WL PUSH OUT INTO LK SUP. WITH A GOOD DEAL OF STRONGER LATE FEB SUNSHINE TO HEAT THIS DRY AIRMASS AND H85 TEMPS PROGGED TO REACH -5C TO -7C BY 00Z MON...EXPECT A HEALTHY DIURNAL TEMP RECOVERY TO PUSH MAX TEMPS WELL INTO THE 30S AT MOST PLACES. AREAS OVER THE E CLOSER TO THE DEPARTING H85 THERMAL TROF AND UNDER A SW FLOW OFF THE CHILLY WATERS OF LK MI WL BE COLDEST. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 342 PM EST SAT FEB 18 2012 SHORTWAVE RIDGE AND SFC HIGH PRESSURE RESULTS IN BENIGN WEATHER SUNDAY NIGHT INTO MONDAY. GOOD AGREEMENT THAT SFC RIDGE AXIS WILL RUN FM SOUTHERN WI THROUGH NORTHERN LOWER MICHIGAN AND INTO SOUTHWEST QUEBEC BY DAYBREAK MONDAY. EXPECT LOWEST TEMPS ON SUNDAY NIGHT OVER INLAND SOUTHERN AND EASTERN CWA CLOSER TO THE RIDGE AND LIGHTER WINDS. BIAS CORRECTED GFS MOS LOOKED BEST...BUT DID SOME ADDITIONAL TWEAK DOWN OF TEMPS OVR INLAND EAST. ATTN ON MONDAY TURNS TO PAIR OF SHORTWAVE TROUGHS THAT WILL BE PUSHING FM THE ROCKIES EAST INTO THE CNTRL AND NORTHERN PLAINS. GFS/ECMWF/CANADIAN INDICATE TWO DISTINCT TROUGHS IN THE PV FIELDS AND THIS STAYS THE CASE RIGHT THROUGH TUESDAY AS THE TROUGHS MOVE ACROSS UPR LAKES. MAIN ISSUE ON MONDAY IS INCREASING MID CLOUDS OUT AHEAD OF UPR TROUGHS. DESPITE CHILLY START...SHOULD BE ANOTHER WARM AFTN AS MIXING TO 925MB-900MB SUPPORTS HIGHS WELL INTO THE 30S. EXPECT NO PRECIP INTO WESTERN CWA BY 00Z TUE. NAM IS SIGNIFICANT OUTLIER BY LIFTING WELL DEFINED H85 CLOSED LOW INTO NORTHERN MN/QPF INTO FAR WESTERN UPR MI BY LATE TUESDAY AFTN. ALL OTHER GUIDANCE HAS MORE OF AN ELONGATED TROUGH FM NEB INTO NW MN AND CONTINUE TO TREND SLOWER IN ARRIVAL OF QPF OVR CWA UNTIL LATER MONDAY NIGHT. HAVE DISCOUNTED THE NAM AND TRENDED TOWARD OTHER MODELS FOR ARRIVAL OF PRECIPITATION. INTO TUESDAY...MAIN DIFFERENCE IS THAT GFS IS MORE PHASED WITH H85 TROUGHS AND HAS MORE MOISTURE ADVECTION INTO THE UPR LAKES. EVEN THE GFS SHOWS THE PRIMARY JET STREAM REMAINING ACROSS THE SOUTHERN TIER. ECMWF AND CANADIAN OFFER MORE TONED DOWN GFS IDEA BUT THEY ARE SHOWING MORE PHASING OF H85 TROUGHS THAN THEY DID EARLIER. RESULT IS MAIN MOISTURE STREAM/HIGHER PWATS STAYING TIED INTO SOUTHERN STREAM SHORTWAVE TRACKING ACROSS OHIO VALLEY INTO CNTRL GREAT LAKES WHILE UPR LAKES/UPR MICHIGAN IS WITHIN REMNANTS OF DEEPER MOISTURE BEING ADVECTED INTO THE NORTHERN STREAM SYSTEM. LIMITED LARGE SCALE PHASING ALLOWS WARMER AIR TO REMAIN TO SOUTH SO SNOW WILL BE MAIN PTYPE. ONLY EXCEPTION IS ALONG IMMEDIATE LK MICHIGAN SHORE WHERE A MIX OF RAIN/SNOW WAS MENTIONED WITH ONSHORE WINDS. BASED ON MAX TEMPS INTO MID 30S CONSIDERED ADDING RAIN MENTION ELSEWHERE...BUT WBZERO HEIGHTS LESS THAN 500AGL WOULD LEAD TO ONLY BRIEF MIXING WITH RAIN BEFORE SNOW TAKES OVER AS MAIN PYTPE. INCREASED POPS INTO THE LIKELY RANGE FOR TUESDAY...ESPECIALLY FIRST PART OF DAY ON TUESDAY OVER WEST AS THAT IS WHEN THE TWO MOISTURE STREAMS WITH THE SHORTWAVES ARE IN GREATEST PROXIMITY. HOWEVER...BASED ON THE GENERAL DOWNWARD TREND TO MOISTURE/LIFT AS TUESDAY GOES ON...IN ADDITION TO FAIRLY WARM BLYR TEMPS IN THE LOWER-MID 30S...PROBABLY WILL NOT BE MUCH FOR SNOW ACCUMS OVER UPR MI FOR MOST OF THE DAYLIGHT HOURS ON TUESDAY. POSSIBLE EXCEPTION WOULD BE IN THE FAR WEST DURING THE MORNING WHERE A FEW INCHES OF SNOW COULD OCCUR VCNTY OF KIWD. BASE OF NORTHERN STREAM TROUGH SETTLES CLOSE BY ON TUESDAY NIGHT WHILE THERE IS STILL LINGERING H85-H7 MOISTURE IN WAKE OF SYSTEM THAT MOVES THROUGH ON TUESDAY. GIVEN THE SETUP...CANNOT RULE OUT SMALL SHORTWAVES ROUNDING BASE OF TROUGH THAT DO NOT SHOW UP IN GUIDANCE RIGHT NOW. CARRIED SMALL CHANCE POPS FOR LGT SNOW SHOWERS/FLURRIES... ESPECIALLY OVER KEWEENAW WHERE WEST WINDS PROVIDE A BIT MORE MOISTENING OFF LAKE SUPERIOR. IN THE EXTENDED...SFC-H85 LOW IS FCST TO BE NORTH OF LK SUPERIOR ON WEDNESDAY. 00Z ECMWF MORE AMPLIFIED WITH SMALLER H85 LOW SLIDING ACROSS IN WESTERLY FLOW WHICH WOULD LEAD TO SWATH OF SYNOPTIC SNOW OVR PORTIONS OF THE CWA ON WEDNESDAY. ECMWF IDEA SEEMS LIKE LOW RISK AT THIS POINT AS PREVIOUS RUNS DID NOT HAVE THIS AND OTHER MEDIUM RANGE MODELS DO NOT SHOW IT AS WELL. INSTEAD WILL GO WITH IDEA THAT MAINLY QUIET CONDITIONS WILL BE AROUND ON WEDNESDAY IN WAKE OF TUESDAY SYSTEM. UPR TROUGH EVENTUALLY SLIDES THROUGH UPR LAKES LATER WEDNESDAY NIGHT INTO THURSDAY...USHERING IN COLDER AIR TO END THE WEEK. CYCLONIC FLOW WITHIN THE SFC-H5 TROUGHINESS ALLOWS DEEPER MOISTURE TO HANG AROUND THURSDAY INTO THURSDAY NIGHT. GIVEN COLD AIR ADVECTION AND THE MOISTURE...PROBABLY WILL SEE ACCUMULATING SNOWS FOR AREAS NEAR LK SUPERIOR FAVORED BY NW WINDS. DRYING FCST TO SPREAD IN FM NW ON FRIDAY AS UPR LOW CENTER SLIDES EAST. DOES COOL OFF SLIGHTLY COMPARED TO THURSDAY THOUGH...SO WOULD EXPECT LK EFFECT TO CONTINUE IN NW FLOW AREAS WITH MAINLY LGT ACCUMS. SAME GOES FOR FRIDAY NIGHT INTO SATURDAY AS SFC-H85 RIDGE IS STUBBORN TO ARRIVE FM THE WEST. KIND OF A CHANGE FROM THE QUICK-MOVING PATTERN THAT HAS BEEN PRESENT OVER THE REGION FOR MOST OF THE WINTER. MAIN CHANGE TO EXTENDED WAS TO INCREASE POPS FOR LK EFFECT AREAS COMPARED TO WHAT ALLBLEND PROCEDURE GENERATED. AWAY FM THE LAKE EFFECT...EXPECT MAINLY CLOUDY CONDITIONS WITH NEAR NORMAL TEMPS FOR LATER FEBRUARY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1231 AM EST SUN FEB 19 2012 DRY LOW-LEVELS ASSOCIATED WITH HIGH PRESSURE RIDGE DRIFTING ACROSS THE WESTERN GREAT LAKES WILL ENSURE VFR CONDITIONS AT KIWD/KSAW THRU THIS FCST PERIOD. WITH A WESTERLY UPSLOPE WIND/CONTINUED OVERWATER TRAJECTORY...OCNL MVFR CIGS MAY STILL OCCUR AT KCMX OVERNIGHT. OTHERWISE...VFR CONDITIONS WILL PREVAIL TODAY AND TONIGHT AT KCMX. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 342 PM EST SAT FEB 18 2012 WITH AN UNSEASONABLY WEAK PRES GRADIENT FORECAST TO DOMINATE THE UPPER GREAT LAKES THIS COMING WEEK...EXPECT WINDS NO HIGHER THAN 25 KTS THIS FORECAST PERIOD. NO GALES ARE LIKELY ANYTIME SOON. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...JLA AVIATION...ROLFSON MARINE...KC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1253 AM EST SUN FEB 19 2012 .SYNOPSIS... A FEW LINGERING FLURRIES WILL SHIFT FROM THE SYRACUSE AREA OVERNIGHT...TO THE FINGER LAKES REGION SUNDAY MORNING...BEFORE HIGH PRESSURE BRINGS QUIET WEATHER THROUGH TUESDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 10 PM...LAST PCPN FROM THE SHRT WV IS NOW WELL EAST AND SOUTH OF THE FCST AREA. BOTH THE WRFARW AND THE HRRR SHOW SOME WEAK LE FOR THE NEXT FEW HRS OVER THE NRN FINGER LAKES IN THE NLY FLOW OFF ONTARIO. 88D COMPOSITE DOES SHOW SOME WEAK ECHOES IN THE AREA SO WILL CONT WITH CHANCE POPS IN THAT AREA FOR THE NEXT FEW HRS. 7PM...SHRT WV IS NOW SLIDING EAST OF THE AREA AND WHAT LOOKS LIKE THE LAST ROUND OF SNOW SHWRS IS MVG THRU THE MIDDLE OF THE FCST AREA. BHD THE WV...JUST SOME LIMITED LE SNOW SHWRS XPCTD WITH LTL ACCUM. TOO MUCH SHEAR AND SIMPLY NOT ALL THAT COLD SO NOT MUCH LE XPCTD. PRVS DISC BLO. A WEAK LOW PRESSURE SYSTEM IS CURRENTLY MAKING ITS WAY INTO THE CWA THIS AFTERNOON. IT WILL MAKE IT ACROSS AND WEAK OVERNIGHT TONIGHT. THERE WILL BE SOME SHOWERS WITH THIS SYSTEM, MAINLY IN THE FORM OF SNOW, BUT SOME AREAS, ESPECIALLY IN NEPA, MAY SEE SOME RAIN. CURRENTLY, RADAR RETURNS OVER NEPA ARE NOT REFLECTING WHAT IS BEING REPORTED BY ASOS AT A COUPLE OF SITES. BOTH MSV AND AVP HAD STRONGER RETURNS PASS DIRECTLY OVERHEAD AND NEITHER REPORTED ANY PRECIPITATION. ON THE OTHER HAND, RME HAD SOME LIGHTER RETURNS AND IS REPORTING MODERATE SNOW. SAME WITH ELZ. THIS MAKES FORECASTING POPS A LITTLE TRICKY. BEST GUESS IS SOME VIRGA, WITH FLURRIES/SPRINKLES AND ISOLATED SHOWERS. THIS WILL CONTINUE THROUGH THE AFTERNOON. THE HRRR DID SHOW THIS TYPE OF RETURNS, SO WILL MODEL POPS AFTER THAT, AT LEAST AS GUIDANCE FOR TIMING. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY/... THIS LOW, AS MENTIONED BEFORE, WILL MOVE ACROSS TONIGHT AND WILL WEAKEN AS IT DOES. SOME COLD AIR ADVECTION WILL FOLLOW BEHIND IT AND MAY KICK OFF SOME LAKE EFFECT SNOW IN THE NORTHERN AND FINGER LAKE ZONES. NOT EXPECTING MORE THEN A COUPLE OF INCHES FROM ANY OF THESE SNOW SHOWERS. BY SUNDAY MORNING, HIGH PRESSURE WILL BEGIN TO BUILD IN AND LAKE EFFECT WILL COME TO AN END SUNDAY MORNING. THIS HIGH PRESSURE WILL KEEP A STRONG LOW PRESSURE SYSTEM WELL TO THE SOUTH OF THE FORECAST AREA. SUNDAY WILL BE THE COOLER DAY, WITH NEAR NORMAL TEMPS IN THE AFTERNOON. THEN, WARM AIR ADVECTION WILL SLOWLY INCREASE TEMPERATURES THROUGH THE MIDDLE OF THE WEEK, WITH UPPER 40S POSSIBLE ON TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... MAIN PLAYER FOR THE PERIOD WILL BE A DEVELOPING MID-LEVEL VORTEX SOUTH OF HUDSON BAY WHICH WILL KEEP MUCH OF THE GREAT LAKES REGION EMBEDDED IN SW FLOW ALOFT. AS IS THE CASE WITH THESE SYNOPTIC SITUATIONS...EMBEDDED SHORTWAVE DISTURBANCES ROTATING ALONG THE SOUTHERN PERIPHERY OF THIS FEATURE WILL RESULT IN AN ACTIVE WX PATTERN FOR MUCH OF THE GREAT LAKES REGION TOWARDS MID/LATE WEEK. GFS AND ECMWF DETERMINISTIC PROGS APPEAR TO BE IN FAIRLY GOOD AGREEMENT TO START OUT THE PERIOD WITH FIRST SHORTWAVE/SFC FRONT EXPECTED TO MOVE THROUGH THE REGION ON WED. WITH ITS ARRIVAL...EXPECT MAINLY A RA/SN MIX WED NGT BEFORE TRANSITIONING TO ALL RA BY LATE WED MORNING/EARLY AFTERNOON. MODELS THEN ADVERTISE A MORE POTENT DISTURBANCE ON THRU AS SECOND SHORTWAVE ROTATES INTO THE REGION. AGAIN...EXPECT RA/SN MIX LATE WED/EARLY THU BEFORE ONCE AGAIN CHANGING OVER TO ALL RA THROUGH THE DAY. MODEL DIFFERENCES DO APPEAR BY THIS POINT HOWEVER AS GFS PHASES BOTH NORTHERN AND SOUTHERN STREAM ENERGY CORES ACROSS THE TENN RVR VLY/SOUTHERN APPALACHIANS BEFORE DEVELOPING A COASTAL LOW BY LATE THU OFF THE HATTERAS COAST. ECMWF ON THE OTHER HAND SHOWS NO INDICATION OF PHASING AND NO SUGGESTION FOR ANY COASTAL DEVELOPMENT. IF THE GFS/S SCENARIO WERE TO PAN OUT...FEATURE LOOKS TO BE A QUICK HITTER WITH MAIN QPF SHIELD REMAINING SOUTH AND EAST OF THE CWA. FUTURE MODEL RUNS MOST CERTAINLY BARE WATCHING. NEXT COLD FRONT EXPECTED TO MOVE THROUGH THE REGION ON FRI WHICH WILL BE FOLLOWED BY THE ARRIVAL OF ARCTIC HIGH PRESSURE AND A CHILLY START FOR NEXT WEEKEND. MODELS SUGGEST H85 TEMPS FALLING TO NEAR -18C WHICH WILL LIKELY RESULT IN A LAKE RESPONSE OFF OF LAKE ONTARIO IN NORTHWEST FLOW ALOFT. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... WEAK NORTHERLY TO NORTH-NORTHWESTERLY FLOW OVER LAKE ONTARIO...WILL LEAD TO THE TYPICAL STRATOCUMULUS DECK DETAIL CONUNDRUMS DURING THE TAF PERIOD...MAINLY FOR CENTRAL NEW YORK TERMINALS. IN GENERAL...LOOKING AT MOST SITES BOUNCING IN AND OUT OF MVFR THROUGH 14Z...AND EVEN SOME LAKE EFFECT FLURRIES SHIFTING FROM KSYR AREA...WESTWARD TO KELM AND PERHAPS KITH. IMPROVEMENT TO AREAWIDE VFR OCCURS BETWEEN 14Z-18Z...WITH VFR ESPECIALLY 18Z- 02Z WHEN ENTRAINMENT OF DRY AIR FROM MID LEVELS WILL BE AT ITS PEAK DURING MIXING HOURS...FOLLOWED BY LOSS OF DIURNAL HEATING AND RESULTING DISSIPATION OF CELLULAR CLOUDS. 02Z- 06Z MONDAY...EXPECTING REDEVELOPMENT OF MVFR STRATOCUMULUS FOR MOST SITES AS MOISTURE GETS TRAPPED AGAIN UNDER INVERSION...COURTESY OF CONTINUED FLOW OFF OF LAKE ONTARIO. .OUTLOOK... LATE SUN NGT/MON MRNG...PERSISTENT MVFR DECK FOR A GOOD CHUNK OF THE AREA FROM MOISTURE TRAPPED UNDER INVERSION...BREAKING UP LATE MON MORNING. MON AFTN/TUE MRNG...MAINLY VFR. TUE AFTN/WED/THU...MVFR AND POSSIBLE IFR IN MIXED PRECIPITATION AS AT LEAST A COUPLE SYSTEMS PASS THROUGH THE REGION. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...SLI/MDP NEAR TERM...DGM/SLI SHORT TERM...SLI LONG TERM...CMG AVIATION...MDP
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1050 PM CST SAT FEB 18 2012 .UPDATE... HIGH PRESSURE OVER THE GREAT LAKES WITH CLEAR SKIES. ONLY REAL PROBLEM IS WEAK NORTHEAST WINDS IN LOW LEVELS SHOULD INCREASE LOW LEVEL MOISTURE SOMEWHAT OFF LAKE MICHIGAN. HOWEVER LOW LEVELS ARE DRY TO START WITH. NAM FORECAST SOUNDINGS WOULD HOLD OFF ANY SCATTERED CU UNTIL AROUND NOON SUNDAY. RUC SOUNDINGS ARE QUICKER AND HAVE A BIT MORE MOISTURE. EITHER WAY EVEN IF SOME CLOUDS DEVELOP EXPECT MAINLY SCATTERED CONDITIONS. && .AVIATION/06Z TAFS/... HIGH PRESSURE OVER THE GREAT LAKES WITH CLEAR SKIES. ONLY REAL PROBLEM IS WEAK NORTHEAST WINDS IN LOW LEVELS SHOULD INCREASE LOW LEVEL MOISTURE SOMEWHAT OFF LAKE MICHIGAN. HOWEVER LOW LEVELS ARE DRY TO START WITH. IF SOME CLOUDS DEVELOP EXPECT MAINLY SCATTERED CONDITIONS. && .PREV DISCUSSION... /ISSUED 326 PM CST SAT FEB 18 2012/ VERY SHORT TERM...TONIGHT AND SUNDAY. TONIGHT - CONFIDENCE...MEDIUM TO HIGH. LIGHT BOUNDARY LAYER WINDS AND CLEAR SKIES WILL ALLOW TEMPS TO FALL INTO THE MID TEENS TO LOWER 20S MOST AREAS. AS THE LOW LEVEL RIDGE AXIS SETS UP TO THE NORTH TONIGHT...ONSHORE FLOW MAY HAVE JUST ENOUGH LOW LEVEL MOISTURE TO CAUSE SOME LAKE CLOUDS TO PUSH ASHORE FROM KMKE SOUTH TO KENW AFT MIDNIGHT TNGT. SUNDAY - CONFIDENCE...HIGH. HIGH PRESSURE DOMINATES. LIGHT WIND REGIME WITH 925 TEMPS SUPPORTING MID/UPPER 30S. 850 TEMPS WARM SO NOT EXPECTING AS MUCH IN THE WAY OF CU DEVELOPMENT. SHORT TERM...SUNDAY NIGHT THROUGH TUESDAY NIGHT. SUNDAY NIGHT AND MONDAY...FORECAST CONFIDENCE MEDIUM TO HIGH. DRY OVER SOUTHERN WISCONSIN SUNDAY NIGHT AND MOST OF MONDAY AS UPPER RIDGING AND SURFACE HIGH MOVE ACROSS WESTERN GREAT LAKES REGION. CLEAR SKIES AND LIGHT WINDS WILL ALLOW TEMPS TO FALL IN THE EVENING ..THEN SLOW OR STEADY OUT AFTER MIDNIGHT AS WEAK SOUTHERLY FLOW STARTS. NAM AN OUTLIER WITH FASTER AND STRONGER WITH LEAD SHORT WAVE AND FARTHER NORTH WITH SURFACE LOW...AS WELL AS ASSOCIATED ISENTROPIC LIFT AND PRECIPITATION PUSHING INTO WESTERN WISCONSIN MONDAY AFTERNOON. WILL GO WITH CONSENSUS AND DELAY ANY PRECIPITATION UNTIL MONDAY EVENING AS DRY AIR AROUND RETREATING SURFACE PREVENTS COLUMN SATURATION UNTIL AROUND/AFTER 00Z TUESDAY. EARLY SUNSHINE WITH A SLOWER SPREAD OF CLOUDS INTO SOUTHERN WISCONSIN AND MIXING UP TO 925 MB TEMPERATURES RISING TO 0C TO +1C WILL YIELD LOW TO MID 40 HIGHS. MONDAY NIGHT THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE MEDIUM. WILL GO WITH A CONSENSUS BLEND FOR TIMING OF PRECIPITATION INTO THE REGION WITH THE EAST DRY AND A CHANCE IN THE WEST THROUGH 06Z...THEN LIKELY POPS IN THE WESTERN TWO-THIRDS BY 12Z TUES AND CHANCE EAST. PRECIPITATION TYPE A CHALLENGE WITH A RAIN/SNOW MIX TO START...CHANGING OVER TO ALL SNOW AS EVAPORATIVE COOLING DROPS COLUMN AND WET BULB TEMPS BELOW 0C. WILL KEEP A SLIGHT CHANCE OF ICE PELLETS/SLEET AS FORECAST SOUNDINGS SHOW SOME RELATIVE WARMTH IN THE 900-850MB LAYER THAT COULD CAUSE SOME PARTIAL MELTING AND THEN RE-FREEZING. LIKELY LIGHT SNOW EVERYWHERE TUESDAY MORNING...CHANGING OVER TO A MIX AS LOWER PORTION OF COLUMN WARMS ABOVE 0C AND DENDRITE GROWTH ZONE DRIES OUT. WHILE MOST OF THE ACCUMULATING PRECIPITATION WILL BE OVER BY 18Z...SECOND SHORT WAVE AND LINGERING CYCLONIC FLOW WILL KEEP CHANCE POPS IN THE NORTHEAST TAPERING TO A SLIGHT CHANCE IN THE SOUTHWEST FOR TUESDAY AFTERNOON...WITH ALL PRECIPITATION ENDING BY 00Z WEDNESDAY. THIS WAVE ALSO PREVENTS WEAK COLD AIR ADVECTION FROM TAKING HOLD UNTIL TUESDAY EVENING. LOWS BY WEDNESDAY MORNING WILL ONLY FALL INTO THE MID TO UPPER 20S. LONG TERM...WEDNESDAY THROUGH SATURDAY. FORECAST CONFIDENCE...LOW TO MEDIUM. MODELS STILL DEPICT REGION REMAINING UNDER BASE OF BROAD TROUGH WITH PERIODIC SHORT WAVE ENERGY MOVING THROUGH THE FLOW EVERY 12 TO 24 HOURS...WITH MODEL TIMING/LOCATION DIFFERENCES. OSCILLATING TEMPERATURES WITH EACH WAVE WILL KEEP PRECIPITATION MIXY...UNTIL PUSH OF COLDER AIR INTO THE REGION FRIDAY INTO THE WEEKEND DROPS 850 MB TEMPERATURES TO -10C TO -14C BY SATURDAY MORNING. MODELS STILL HAVING DIFFICULTY RESOLVING A POTENTIALLY STRONG STORM FOR THE END OF FEBRUARY. 12Z GFS IS TRENDING TOWARD THE 00Z ECMWF WITH A DEEP SURFACE LOW OVER WESTERN MINNESOTA NEXT SUNDAY EVENING...TRACKING ENE ACROSS LAKE SUPERIOR/FAR SOUTHERN CANADA A WEEK FROM THIS MONDAY. 12Z ECMWF HAS BACKED OFF ON STRENGTH OF WAVE AND ASSOCIATED SURFACE LOW. WAY TOO EARLY...BUT BEARS WATCHING OVER THE NEXT FEW DAYS. AVIATION/00Z TAFS/...VFR SKC FOR MUCH OF THE AREA THROUGH SUNDAY. ONLY QUESTION IS NEAR THE LAKE WHERE DELTA T AND TRAJECTORIES MAY SUPPORT A WINDOW OF TIME FOR SOME LAKE CLOUDS LATER TONIGHT INTO SUNDAY MORNING THOUGH CONFIDENCE TOO LOW FOR TAF INCLUSION. SURFACE HIGH CONTINUES TO BUILD IN TONIGHT AND SUNDAY. OVERALL LESS CU POTENTIAL FOR MUCH OF SUNDAY WITH WARMING 850 TEMPS AND NO APPRECIABLE CHANGE IN SURFACE DEW POINTS. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...HENTZ TONIGHT/SUNDAY AND AVIATION/MARINE...COLLAR SUNDAY NIGHT THROUGH SATURDAY...REM
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
731 AM CST SUN FEB 19 2012 .UPDATE... ISSUED AT 716 AM CST SUN FEB 19 2012 THE STRATUS DECK IS VERY EXTENSIVE ACROSS THE HIGH PLAINS THIS MORNING. THE 00 AND 06 NAM DID NOT HANDLE THE EVOLUTION OF THE STRATUS VERY WELL AT ALL. THE 12Z SOUNDING FROM DODGE CITY SHOWS A NEARLY SATURATED LAYER FROM 1400 FT AGL UP TO AROUND 3000 FT AGL, WHILE THE NAM WAS DRY IN THIS LAYER AND ONLY INDICATED SKIN DEEP MOISTURE. THE RUC IS DOING A LITTLE BETTER JOB AND RUC SOUNDINGS INDICATE LOW CLOUDS HANGING ON THROUGH MID-DAY AT GCK/DDC. THUS, MAXIMUM TEMPERATURES WERE LOWERED A FEW DEGREES ALONG A CORRIDOR FROM DODGE CITY TO DIGHTON AND GARDEN CITY AND CLEARING WAS POSTPONED IN THE GRIDS UNTIL LATE MORNING AND EARLY AFTERNOON. AFTER THE LOSS OF DAYTIME HEATING, EXTENSIVE LOW CLOUD COVER SHOULD REDEVELOP BETWEEN 02 AND 05Z. THE NAM HOLDS OFF ON STRATUS DEVELOPMENT UNTIL 09-10Z AND THIS IS PROBABLY IN ERROR. SKY COVER GRIDS WERE UPDATED TO REFLECT THIS THINKING. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 320 AM CST SUN FEB 19 2012 THE MAIN FORECAST CHALLENGES ARE CHANCES FOR ISOLATED THUNDERSTORMS LATE TONIGHT AND STRONG WINDS THIS AFTERNOON AND OVERNIGHT. A STRONG UPPER LEVEL TROUGH WILL MOVE FROM THE WESTERN CONUS AND INTO THE INTERMOUNTAIN WEST TODAY THEN INTO THE ROCKIES TONIGHT. THIS SYSTEM WILL PUSH A WARM FRONT ACROSS FAR WESTERN KANSAS TODAY AND THROUGH CENTRAL KANSAS TONIGHT. AS THE TROUGH APPROACHES THE PRESSURES WILL DROP AS A LOW DEVELOPS IN EASTERN COLORADO. THIS WILL CAUSE A STRONG PRESSURE GRADIENT ACROSS WESTERN KANSAS TODAY AND SOUTH WINDS COULD BE CLOSE TO WIND ADVISORY. HOWEVER SOME MID TO HIGH LEVEL CLOUDINESS MAY OFFSET GOOD MIXING. FOR NOW WILL KEEP WINDS FROM THE SOUTH AT 20 TO 30 MPH AND GUSTY. A STRONG INVERSION IS ALSO FORECAST AT AROUND 750MB THAT COULD TRAP SOME OF THE CURRENT STRATUS. IF MORE SUN COMES OUT WINDS COULD BE INTO ADVISORY LEVEL. HIGHS TODAY WILL BE NEAR 60 IN THE FAR WEST AROUND SYRACUSE AND ELKHART TO THE LOW 50S EAST FROM HAYS TO MEDICINE LODGE. TONIGHT A LOW LEVEL JET IS FORECAST AS AN UPPER LEVEL DRY SLOT MOVES INTO WESTERN KANSAS. THE BEST MOISTURE AND LIFT LOOK TO BE FROM WAKEENEY TO DODGE CITY AND HAYS WITH A DRY LINE MOVING IN FROM THE WEST LATE TONIGHT. FORECAST SOUNDINGS SHOW SOME ELEVATED CAPE AFTER MIDNIGHT SO KEPT 20 TO 30 POPS GOING AND ADDED SOME ISOLATED THUNDER. SURFACE WINDS SHOULD ALSO STAY UP AT 20 TO 30 MPH OVERNIGHT WITH MILD OVERNIGHT LOWS. WILL KEEP CURRENT LOWS FROM THE LOW TO MID 30S FAR WEST TO AROUND 40 EAST. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 339 AM CST SUN FEB 19 2012 A STRONG SHORTWAVE TROUGH MOVING INTO THE NORTHWESTERN UNITED STATES THIS AFTERNOON WILL RAPIDLY PROGRESS ACROSS THE CENTRAL ROCKIES BY SUNDAY NIGHT AND THEN ACROSS KANSAS BY MONDAY AFTERNOON. THE ECMWF/UKMET AND GEM WERE NOT CLOSED OFF WHILE THE NAM/GFS SHOW A CLOSED UPPER-LOW OVER KANSAS BY MONDAY AFTERNOON. HAVING BEEN SHUNTED INTO THE GULF OF MEXICO BY THE PREVIOUS STRONG UPPER-LEVEL SYSTEM, RICH LOW-LEVEL MOISTURE (50S AND 60S SURFACE DEWPOINTS) WILL NOT RETURN INTO THE SOUTHERN PLAINS AHEAD OF THIS SYSTEM. DESPITE THIS, THE NAM/GFS DO NOT MAKE A CLEAN SWEEP OF THE MARGINAL 40-45F DEWPOINTS INTO THE GULF OF MEXICO. IN FACT, THE NAM SHOWS A NEARLY SATURATED LAYER BETWEEN THE SURFACE AND 1 KILOMETER INTO SOUTHWEST KANSAS BY 12Z MONDAY, SO WIDESPREAD, LOW STRATUS IS LIKELY IN THE MORNING MONDAY. AS THE UPPER SYSTEM TRAVERSES KANSAS MONDAY, THIS LOW- LEVEL MOIST AXIS IS EXPECTED TO SHIFT INTO EASTERN KANSAS. THE 500MB COLD POOL WITH THIS TROUGH WILL BE VERY IMPRESSIVE, WITH TEMPERATURES AS LOW AS -29C. SURFACE BASED THUNDERSTORMS WITH POSSIBLE SEVERE WEATHER SHOULD STAY TO OUR EAST AND SOUTHEAST MONDAY AFTERNOON. BUT INCREASING MID-LEVEL RELATIVE HUMIDITY AND VERY COLD MID-LEVEL TEMPERATURES COULD RESULT IN SHOWERS ACROSS SOUTHWEST KANSAS. ALL THE PRECIPITATION OUGHT TO BE IN LIQUID FORM DUE TO WARM BOUNDARY LAYER TEMPERATURES, ESPECIALLY IF THE LESS CLOSED OFF SOLUTION THAT WE FAVOR ACTUALLY VERIFIES. THE ASSOCIATED COLD FRONT WILL PASS ACROSS WESTERN KANSAS LATE MONDAY AFTERNOON AND MONDAY EVENING. 25 TO 30 KT WINDS ARE LIKELY BEHIND THE FRONT MONDAY AFTERNOON AND EVENING AND A WIND ADVISORY WILL LIKELY BE NEEDED. AFTER THE AFOREMENTIONED SYSTEM PASSES, THE MID TO UPPER-LEVEL FLOW WILL BECOME NORTHWESTERLY, WITH UPPER-LEVEL RIDGING NEAR THE WEST COAST, AND LOW AMPLITUDE TROUGHING OVER THE GREAT LAKES AND EASTERN UNITED STATES. OF COURSE, THIS IS A DRY PATTERN FOR WESTERN KANSAS AS ANY LOW-LEVEL GULF MOISTURE SHOULD BE DIRECTED WELL TO OUR EAST. TEMPERATURES WILL BE A FEW DEGREES ABOVE CLIMATOLOGY BEHIND THE PACIFIC COLD FRONT ON TUESDAY AS LOW-LEVEL WINDS WILL BE DOWNSLOPE FROM THE WEST. BY WEDNESDAY, THE GFS/ECMWF SUGGEST CONTINUING LOW-LEVEL DOWNSLOPE FLOW FROM THE WEST AS A SHORTWAVE TROUGH PASSES ACROSS THE NORTHERN PLAINS. TEMPERATURES COULD REACH INTO THE MID 60S AHEAD OF THE ASSOCIATED COLD FRONT. ONCE THAT SHORTWAVE TROUGH PASSES FURTHER EAST, THE COLD FRONT SHOULD PROGRESS THROUGH WESTERN KANSAS BY WEDNESDAY NIGHT, LEADING TO FAIRLY SEASONABLE TEMPERATURES FOR THURSDAY AND FRIDAY. THE ECMWF AND GEM CONTINUE TO BE INCONSISTENT WITH THE AMPLITUDE AND LOCATION OF AN UPPER-LEVEL TROUGH OVER THE WESTERN UNITED STATES BY FEBRUARY 26TH. BUT IF THE DEEPER SOLUTION VERIFIES, THEN PRECIPITATION WOULD BE POSSIBLE IN PARTS OF THE PLAINS REGION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 606 AM CST SUN FEB 19 2012 LOW STRATUS HAS ENVELOPED THE TAF SITES. THE NAM IS DOING A BAD JOB WITH THE LOW CLOUD DECK. BELIEVE THE STRATUS WILL BE MUCH SLOWER TO BURN OFF, WITH IFR OR LOW MVFR CIGS PERSISTING THROUGH 16Z. EXPECT IFR CIGS TO RETURN BETWEEN 03 AND 06Z TONIGHT AS THE BOUNDARY LAYER COOLS AND A LOW LEVEL JET SETS UP. && .PRELIMINARY POINT TEMPS/POPS... DDC 49 39 55 26 / 0 20 20 0 GCK 50 36 50 24 / 0 10 20 0 EHA 58 35 49 22 / 0 10 20 0 LBL 54 38 52 26 / 0 10 20 0 HYS 50 38 53 26 / 0 30 30 20 P28 52 41 58 28 / 0 30 20 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...FINCH SHORT TERM...KRUSE LONG TERM....FINCH AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
555 AM CST SUN FEB 19 2012 ...UPDATE TO AVIATION... && .AVIATION... VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WINDS BECOME SOUTHEAST LATE THIS MORNING AND SLOWLY INCREASE BY MID DAY. EXPECT FURTHER INCREASE IN WIND SPEED AND CLOUD COVER TOWARD END OF THE TAF PERIOD BUT TOO FAR OUT /AFTER 09Z/ TO INCLUDE AT THIS TIME. 67 && .PREV DISCUSSION... /ISSUED 346 AM CST SUN FEB 19 2012/ SHORT RANGE FORECAST (TODAY AND MONDAY)... EARLY MORNING 11 TO 3.9 MICRON SATELLITE IMAGERY INDICATES THAT ALL OF NORTHEAST KANSAS REMAINS UNDER MOSTLY CLEAR SKIES. 08Z WATER VAPOR IMAGERY AND THE ASSOCIATED RUC UPPER AIR ANALYSIS SHOWS A WEAK UPPER TROUGH MOVING EASTWARD INTO NORTHERN MISSOURI. THIS TROUGH WILL NOT HAVE MUCH AFFECT ON THE REGION THIS MORNING AS IT EXITS TO THE EAST. ALSO TO THE WEST...THE NEXT UPPER WAVE IS BEGINNING TO DIG INTO THE INTERIOR WESTERN US AND SHOULD BE CROSSING THE GREAT DIVIDE ON SUNDAY NIGHT. THIS WESTERN TROUGH WILL BE THE ONE TO WATCH AS WE HEAD INTO NEXT WEEK. BETWEEN THE TWO UPPER TROUGHS IS A SHORTWAVE RIDGE WHICH WILL MOVE OVER THE AREA FOR SUNDAY. SOUTHERLY WINDS WILL PICK UP THROUGHOUT THE DAY ON SUNDAY...WHICH IN COMBINATION WITH THE UPPER RIDGE SHOULD ALLOW TEMPS TO WARM UP A BIT FROM SATURDAY. EXPECT TEMPS TO RISE INTO THE LOWER 50S TODAY AS THE LOWER ATMOSPHERE SHOULD BE ABLE TO MIX TO AROUND 850 MB ON SUNDAY. SOUTHERLY WINDS WILL PERSIST THROUGH THE NIGHT AS THE SURFACE WAVE DEEPENS AS IT COMES OFF THE HIGH PLAINS. THE LASTING SOUTHERLY FETCH SHOULD ALLOW DECENT MOISTURE (FOR THIS TIME OF YEAR) TO RETURN INTO THE CENTRAL PLAINS. MODELS FOR A COUPLE DAYS HAVE HINTED AT LOWER TO MID 40 DEWPOINTS REACHING INTO NORTHEAST KANSAS IN ADVANCE OF THE NEXT TROUGH. TAKING A CUE FROM THE 00Z AND 06Z NAM HAVE INTRODUCED SOME THUNDER TO THE GOING FORECAST AS MODELS HAVE NOW INDICATED ENOUGH MOISTURE INFLUX AND STEEP ENOUGH MID LEVEL LAPSE RATES TO GENERATE UP TO 500-700 J/KG OF MUCAPE DURING THE DAY ON MONDAY. WITH THAT MUCH INSTABILITY IT SEEMS ALMOST LIKELY AT THIS POINT THAT THUNDERSTORMS WILL BE EMBEDDED WITHIN THE MONDAY RAIN SHIELD. ONCE THE MAIN UPPER WAVE ENTERS THE CENTRAL PLAINS ON MONDAY AFTERNOON/EVENING IT WOULD PROVIDE ENOUGH LIFT TO KICK OFF RAIN SHOWERS ACROSS THE ENTIRE FORECAST AREA. SURFACE AND LOW LEVEL WINDS SHOULD BE BACKED ON MONDAY AFTERNOON WHICH IN CONJUNCTION WITH S-SWLY FLOW IN THE LOW TO MID LEVELS WILL ALLOW FOR SOME TURNING IN THE ATMOSPHERE. WITH 0-6 SHEAR EXPECTED TO BE ON THE ORDER OF 40 TO 50 KNOTS...THE COMBINATION OF INSTABILITY WITH SHEAR MAY ALLOW FOR SOME ISOLATED STRONG THUNDERSTORMS WHICH WOULD ALSO BRING AN ISOLATED HAIL THREAT FOR MONDAY. ONCE THE SUN SETS ON MONDAY NIGHT THE INSTABILITY SHOULD WANE RAPIDLY...SO ANY LINGERING SHOWERS BEYOND 8 PM TO 9 PM ON MONDAY SHOULD BE LIGHT STRATIFORM RAIN AS OPPOSED TO THUNDERSTORMS. EXPECT PRECIP TO EXIT THE AREA COMPLETELY BY AROUND MIDNIGHT ON TUESDAY MORNING. MID RANGE AND EXTENDED FORECAST (TUESDAY THROUGH SATURDAY)... A RATHER MILD AND UNSEASONABLY WARM WEEK IS ON TAP ONCE THE RAIN SHOWERS EXIT ON TUESDAY MORNING. A RATHER PRONOUNCED DOWN SLOPE COMPONENT TO THE WINDS PRESENTS ITSELF FOR TUESDAY AND WEDNESDAY WHICH SHOULD AID IN WARMING TEMPS FOR THE MID TO LATE WEEK TIME PERIOD. BROAD UPPER WAVE THEN SLIDES SOUTHEASTWARD LATE IN THE WEEK...WHICH WILL BRING AN ISOLATED CHANCE FOR SOME PRECIP IN THE FAR NORTHEASTERN CORNER OF THE STATE. SURFACE HIGH THEN DROPS SOUTHWARD ON THURSDAY INTO FRIDAY...WHICH WILL BRING A COOLING TREND FOR THE LATE HALF OF THE WEEK. SINCE THE AIR MASS DOES NOT LOOK TO BE ARCTIC IN NATURE EXPECT TEMPERATURES TO REMAIN AT OR SLIGHTLY ABOVE SEASONAL NORMALS. JL && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
933 AM EST SUN FEB 19 2012 .SYNOPSIS... A QUICK MOVING LOW PRESSURE SYSTEM OVER THE NORTHEAST THIS MORNING WILL GIVE WAY TO HIGH PRESSURE RIGHT ON INTO TUESDAY. THIS WILL BE FOLLOWED BY A FRONTAL BOUNDARY WEDNESDAY...THEN A COUPLE OF LOWS THAT WILL BRING PRECIPITATION THROUGH THE END OF THE WEEK. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... AS OF 929 AM EST SUNDAY...MINOR UPDATE TO INCREASE CLOUDS ACRS THE MTNS AND MENTION SOME FLURRIES. CRNT VIS SATL PIC SHOWS AREAS OF CLOUDS/CLRING THIS MORNING...BUT KWMW 12Z SOUNDING SHOWS SOME MOISTURE TRAPPED BLW DEVELOPING TEMP INVERSION. IN ADDITION...LATEST RUC13 AND BTV4 RH PROFILES SHOW ENOUGH MOISTURE BTWN SFC AND 850MB TO PRODUCE SOME CLOUDS TODAY...ESPECIALLY ACRS THE MTNS. THEREFORE...WL MENTION PARTLY SUNNY SKIES AND WITH UPSLOPE NW FLW A FEW FLURRIES WL BE POSSIBLE...ESPECIALLY THIS AFTN WITH STEEPENING LLVL LAPSE RATES. OTHERWISE...TEMPS WL RANGE FROM L20F MTNS/SLK/NEK TO M30 VSF. PREVIOUS DISCUSSION...THRU THE EVENING/OVERNGT HRS...THE CWA WILL SEE GENERAL CLRING TREND AS WK SHORTWAVE DISSIPATES DURING THE DAY AND BE REPLACED BY STRONG SFC HIGH PRESSURE SYSTEM. WILL BE KEEPING CLD COVER MCLDY/CLDY FOR CWA THRU MORNING HRS W/ CHANCE FOR A FLURRY/LGT -SW...ESPECIALLY FOR HIR TRRN. NO ACCUM EXPECTED. CD POOL AHEAD OF RIDGE WILL SINK OVER THE CWA BY TNGT. 850 TEMPS NEAR -8C TO -10C. GUIDANCE APPEARS A BIT TOO CD FOR OVERNGT LOWS SO WILL UP BY A FEW DEGREES...BUT STILL LOOKING FOR TEENS IN MOST SPOTS. && .SHORT TERM /10 PM THIS EVENING THROUGH TUESDAY/... AS OF 313 AM EST SUNDAY...NICE COUPLE OF DAYS ON TAP FOR THE NORTH COUNTRY AS LARGE SFC RIDGE SHIFTS SLOWLY EAST FROM THE GREAT LKS TO THE EAST COAST. CWA WILL BE ON CD SIDE OF RIDGE FOR MONDAY W/ LGT NNE FLOW. RIDGE CRESTS OVER THE REGION MONDAY NGT AND SHIFTS OFF THE EAST COAST FOR TUESDAY. INCR WAA WILL ENSUE DURING THE DAY TUESDAY AS SOUTHERLY FLOW KICKS IN. JET OUT AHEAD OF APPROACHING SYSTEM FOR MIDWEEK WILL PROVIDE GUSTY CONDITIONS NEAR 20-30MPH. MDL TIMING FOR NEXT SYSTEM APPROACHING FOR LATE TUESDAY OVER WESTERN N NY. WILL BRING IN SL CHANCE FOR PRECIP LATE IN THE DAY MAINLY OVER ST LAW VALLEY WHERE A FEW -RW/-SW COULD FALL. LITTLE TO NO QPF FOR THIS TIME FRAME. TEMPS AT OR BLW NORMAL MON/MON NGT AS RIDGE CREST OVER AREA...BUT SEVERAL DEGREES ABV NORMAL WITH HIGHS NEAR 40F FOR TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... AS OF 340 AM EST SUNDAY...FINALLY SOME INTERESTING WX TO DISCUSS AS WE PROGRESS INTO THE MIDDLE AND LATTER PORTIONS OF NEXT WEEK. MODELS CONTINUE IDEA OF A MEAN WEST COAST/EPAC RIDGE...AND A BROAD CENTRAL CONUS TROUGH...WHICH PROGRESSES SLOWLY EAST THROUGH THE PERIOD. BEING ON THE EASTERN/FRONT END OF THIS TROUGHING...THE NORTHEAST WILL EXPERIENCE MILD THOUGH RATHER UNSETTLED WX AS A SERIES OF MODEST LOW PRESSURE SYSTEMS RIDE ENE INTO THE REGION IN THE BROAD SOUTHWESTERLY FLOW ALOFT. FIRST SYSTEM AND ASSOCIATED OCCLUSION WILL SWING THROUGH THE REGION TUE NIGHT INTO EARLY WEDNESDAY WITH SCT RAIN/SNOW SHOWER ACTIVITY. PTYPE TO BE GOVERNED BY TIME OF DAY AND ELEVATIONAL DIFFERENCES...TYPICAL AS WE PROGRESS INTO LATE WINTER WHEN NEAR SFC TEMPERATURE STRUCTURE BECOMES MORE HEAVILY INFLUENCED BY INSOLATION. PERHAPS SOME MINOR ACCUMULATIONS ACROSS THE HIGHER TERRAIN DURING THIS PERIOD...ESP IN THE OVERNIGHT HOURS...BUT AS IS TYPICAL WITH FRONTAL OCCLUSIONS AMOUNTS SHOULD BE LIGHT. LOWS TUESDAY NIGHT 27 TO 35...AND HIGHS ON WEDNESDAY IN THE LOWER TO MID 40S PER MEAN 925 HPA TEMPS OF +1 TO +2C. A BRIEF PERIOD OF CLOUDY THOUGH MAINLY DRY WX THEN EXPECTED BY LATER WEDNESDAY INTO WEDNESDAY NIGHT BEFORE ADDITIONAL AND SLIGHTLY STRONGER ENERGY PROGRESSES EAST INTO THE REGION BY THURSDAY INTO FRIDAY. HAVE OFFERED A BLENDED ECWMF/GFS SOLN DURING THIS PERIOD...WHICH APPEARS TO HAVE MERIT GIVEN UNCLIMATOLOGICAL INLAND STRENGTHENING OF THE LOW PRESSURE CENTER OFFERED BY THE GFS...AND THE PROSPECT OF SEVERAL DIFFICULT TO TIME ENERGY BUNDLES SWINGING THROUGH THE REGION. THIS WOULD SUGGEST A RATHER SHARP FRONTAL BOUNDARY SETTING UP OVER OR JUST NORTH OF OUR REGION WITH A MEAN STORM TRACK THROUGH SLV AND AN INCREASING CHANCE OF RAIN/SNOW SHOWER ACTIVITY. TEMPERATURE/QPF FORECAST QUITE TRICKY WITH INCREASING EVIDENCE OF STRONG BAROCLINICITY AND INCREASING FRONTOGENETICAL FORCING OVER OUR AREA. INDEED...COULD BE ONE OF THOSE PERIODS WHERE THE FAR NORTH REMAINS STUCK IN THE 30S WHILE SOUTHERN COUNTIES NEAR THE 50F MARK. THUS A BLENDED SOLN SEEMS THE BEST ROUTE. AGAIN...GIVEN THE UNCERTAINTY IN THE LOW LEVEL THERMAL STRUCTURE...PRIMARY PTYPE WILL BE RAIN SHOWERS IN THE VALLEYS...AND A MIX OF RAIN/SNOW SHOWERS IN THE MTNS THU/FRI. AS FRONT PUSHES SOUTH OF THE AREA LATER FRIDAY...PCPN WILL TRANSTION TO SHSN IN ALL AREAS AS COLDER AIR FILTERS INTO THE REGION. THEN GENERALLY DRY AND SEASONABLY COLD BY NEXT SATURDAY AS HIGH PRESSURE BUILDS INTO THE REGION. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... THROUGH 12Z MONDAY...SCT/BKN VFR CIGS FROM FL035-050 EXPECTED THROUGH THE PERIOD UNDER NORTH TO NORTHWESTERLY WINDS 3-7 KTS. ONLY EXCEPTIONS AT KSLK/KMPV WHERE OCCNL MVFR CIGS FROM FL018-028 POSSBL THROUGH 16Z. NO PCPN EXPECTED. OUTLOOK 12Z MONDAY THROUGH THURSDAY... 12Z MONDAY THROUGH 00Z WEDNESDAY...VFR UNDER HIGH PRESSURE. 00Z WEDNESDAY THROUGH 00Z THURSDAY...MAINLY VFR WITH OCCNL MVFR/IFR RAIN/SNOW SHOWERS POSSIBLE AS WEAK LOW PRESSURE PASSES NORTH OF THE REGION WITH OCCLUDED FRONTAL PASSAGE. 00Z THURSDAY THROUGH 00Z FRIDAY...NEXT SHORTWAVE TROUGH AND ASSOCIATED SFC LOW BRINGS A CHANCE OF RAIN OR SNOW SHOWERS... THOUGH TIMING AND SPATIAL DETAILS ARE NOT WELL RESOLVED ATTM. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JN NEAR TERM...JN/TABER SHORT TERM...JN LONG TERM...JMG AVIATION...JMG
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
550 AM CST SUN FEB 19 2012 .DISCUSSION.../ISSUED AT 415 AM CST/ MAIN FORECAST CONCERN WILL FOCUS ON A TROUGH CURRENTLY DIGGING INTO THE INTERMOUNTAIN WEST THIS MORNING. THE BIG FORECAST CHALLENGE WITH THIS SYSTEM WILL BE PRECIPITATION TYPE WITH VERY LITTLE COLD AIR ASSOCIATED WITH THE SYSTEM AND LOW LEVEL TEMPERATURES LIKELY TO HOVER RIGHT AROUND FREEZING. AHEAD OF THIS TROUGH.... BREEZY SOUTHERLY WINDS WILL BRING IN A GOOD SHOT OF WARM AIR ADVECTION TODAY AS 925 MB TEMPERATURES RISE ABOVE ZERO ACROSS THE CWA. THIS ADVECTION WILL BE GREATEST IN THE JAMES RIVER VALLEY INTO SOUTH CENTRAL SOUTH DAKOTA WHICH SHOULD EASILY MIX DOWN INTO THE LOWER 50S THIS AFTERNOON...WITH THE REST OF THE CWA IN THE 40S. CLOUDS WILL BE ON THE INCREASE THIS AFTERNOON AND OVERNIGHT AS THE UPPER LEVEL TROUGH DIGS INTO THE FOUR CORNERS REGION WHILE THE MID LEVEL TROUGH BEGINS EMERGING INTO THE CENTRAL HIGH PLAINS. WITH MOISTURE INCREASING RAPIDLY OVERNIGHT AND BREEZY WINDS PERSISTING PAST SUNSET...TEMPERATURES WILL LIKELY FALL OFF SOME IN THE LATE EVENING...AND THEN REMAIN FAIRLY STEADY OR SLIGHTLY RISE AFTER MENDICANT. TEMPERATURES PROFILES SUGGEST THAT TEMPERATURES COULD RISE TO NEAR OR JUST ABOVE FREEZING ACROSS THE BULK OF THE CWA BY 12Z MONDAY. PRECIPITATION WILL START INTENSIFYING ACROSS OUR WESTERN HALF LATE SUNDAY NIGHT AND EARLY MONDAY...WITH PRECIPITATION STARTING OUT AS SNOW OR A RAIN AND SNOW MIX. COULD SEE SOME SLEET TOWARDS THE ONSET OF THE PRECIPITATION...BUT THINK THAT FZRA OR FZDZ THREAT IS MINIMAL WITH SURFACE TEMPERATURES POTENTIALLY TOO WARM EVEN AT ONSET OF PRECIPITATION. PRECIPITATION WILL GRADUALLY SHIFT EASTWARD THROUGH THE DAY AND HAVE EXPANDED THE CATEGORICAL POPS ACROSS THE FORECAST AREA ON MONDAY. WITH VERY LITTLE COLD AIR ADVECTING INTO THE PLAINS WITH THE ARRIVAL OF THE TROUGH...EXPECT TEMPERATURES TO PEAK IN THE MID 30S TO NEAR 40 UNDER THE ROBUST SOUTHERLY FLOW. BY LATE MORNING...THE MISSOURI RIVER VALLEY WILL LIKELY SWITCH OVER TO RAINFALL...WHICH COULD EXTEND AS FAR NORTHWARD AS THE US 14 CORRIDOR BY THE AFTERNOON. WINDS SWITCH AROUND TO THE NORTH BEGINNING MONDAY AFTERNOON ALONG OUR WESTERN BORDER...ALLOWING RAIN TO TRANSITION BACK TO SNOW FROM WEST TO EAST OVERNIGHT. THIS TRANSITION WILL BE FAIRLY BRIEF WITH THE SYSTEM EXITING TO OUR EAST AND THE PRECIPITATION TAPERING OFF OVERNIGHT. SNOWFALL AMOUNTS REMAIN TRICKY TO PINPOINT FOR THIS EVENT AND WILL BE LARGELY DEPENDENT UPON SURFACE TEMPERATURES AND PRECIPITATION INTENSITY. GFS...ECMWF AND GEM PAINT DECENT INSTABILITY AND STRONG MID LEVEL LIFT WHICH SHIFTS NORTHWARD THROUGH THE JAMES RIVER VALLEY INTO THE MADISON AND BROOKINGS AREA BY MONDAY AFTERNOON. WHILE TEMPERATURE PROFILES SUGGEST MAINLY RAINFALL OR AT BEST A MIX...THE MORE INTENSE SNOWFALL BANDS COULD OVERCOME THE RELATIVELY WARM SURFACE TEMPERATURES AND BRING MORE SIGNIFICANT SNOWFALL ACCUMULATIONS. AT THIS POINT...WILL KEEP AMOUNTS CONSERVATIVE AND CONTINUE TO MONITOR THE SITUATION. WITH OUR NORTHERN BORDER INTO SOUTHWEST MINNESOTA LIKELY TO HOLD ONTO SNOWFALL THE LONGEST...HAVE PLACED THE HIGHEST ACCUMULATIONS THERE. ELEVATION COULD ALSO PLAY AN INTERESTING ROLE...BRINGING LOCALLY HIGHER AMOUNTS TO THE BUFFALO RIDGE AREA IN PARTICULAR. DESPITE QPF AMOUNTS OF A QUARTER TO HALF INCH...POOR SNOW GROWTH...MILD TEMPERATURES AND POSSIBLE RAIN WILL KEEP SNOW RATIOS ON THE LOW END OF THE SPECTRUM. GENERALLY WENT WITH AROUND AN 8:1 RATIO ON MONDAY AND SLIGHT HIGHER BOOKEND AMOUNTS. THE END RESULT IS STORM TOTAL SNOWFALL 2 TO 4 INCHES NORTH OF A KHON TO KFSD TO KSPW LINE. GIVEN THE LONG DURATION OF THIS EVENT AND THE POTENTIAL MELTING OF SNOW WITH RAIN...WILL NOT ISSUE ANY HEADLINES WITH THIS PACKAGE. CLOUDS WILL BE ON THE DECREASE ON TUESDAY WITH NORTHWEST FLOW ARRIVING IN THE WAKE OF THE EXITING SYSTEM. TEMPERATURES ARE EXPECTED TO REMAIN MILD WITH HIGHS BACK INTO THE UPPER 30S AND LOWER 40S. / FOR THE EXTENDED RANGE /WEDNESDAY THROUGH SATURDAY/ THE GENERAL LARGE SCALE IDEA OF CARVING OUT A CYCLONIC FLOW BY MID TO LATE WEEK AS POLAR VORTEX SETTLES ACROSS HUDSON BAY IS WELL RECEIVED IN A VAST MAJORITY OF SOLUTIONS. IT IS THE DAY TO DAY LOCATION AND TRACK OF THE QUICK MOVING WAVES IN THE CYCLONIC NORTHWEST FLOW THAT IS A HUGE INCONSISTENCY. DID NOT SEE REASON TO ALTER SIGNIFICANTLY THE 20 TO 30 POPS FOR WEDNESDAY THROUGH THURSDAY PERIOD WITH VARIETY OF ILL TRACKED AND TIMED WAVES. MOST CONSISTENT FEATURE WOULD PROBABLY BE THE LATER TUESDAY NIGHT INTO WEDNESDAY WAVE...BUT TEMPERATURES ARE SUCH THAT WOULD BE CONCERNED FOR SOME RAIN/SNOW MIX. COOLER AIR WILL FILTER SOUTHWARD...WITH BULK OF COOLING WORKING IN BEHIND WAVE FOR LATER WEDNESDAY NIGHT AND THURSDAY...WHATEVER TRACK IT ENDS UP TAKING. NUMEROUS SOLUTIONS OF GFS ENSEMBLE ARE STRONGER WITH LOBE WRAPPING SOUTHWARD THROUGH MINNESOTA ON THURSDAY. DIURNAL RANGE SHOULD BE SOMEWHAT RESTRAINED INTO THURSDAY BEFORE DRYING OUT THE PRECIP THREAT AND BUILDING LOW LEVEL RIDGE IN OVER THE AREA BY FRIDAY NIGHT. /CHAPMAN && .AVIATION.../FOR THE 12Z TAF ISSUANCE/ VFR CONDITIONS SHOULD PREVAIL ACROSS THE CWA THROUGH 06Z MONDAY. HOWEVER...WILL HAVE TO KEEP TABS ON THE STRATUS FROM WESTERN KANSAS INTO SOUTHWEST NEBRASKA...AS LATEST RUC SUGGESTS THAT THIS AREA COULD MOVE INTO SOUTH CENTRAL SOUTH DAKOTA AFTER 18Z...AND IF IT DOES NOT MIX OUT AS INDICATED...COULD IMPACT AREAS WEST OF THE JAMES VALLEY AS EARLY AS 21Z-00Z...BUT MORE LIKELY TO DISSIPATE AND REDEVELOP AFTER 06Z. FOCUS OF WARM AIR ADVECTION WITH SOMEWHAT UNSTABLE PROFILE SHOULD ALLOW PRECIP TO DEVELOP FAIRLY RAPIDLY IN THE 06Z-09Z TIMEFRAME FROM NEBRASKA INTO CENTRAL SD...AND THEN ADVECT RAPIDLY NORTH/NORTHEAST. THERMAL PROFILES SUGGEST THAT TYPE IS STILL SOMEWHAT IN QUESTION...BUT SHOULD EITHER BE RAIN OR SNOW... AS IF TEMPERATURES WARM...THEY SHOULD WARM ENOUGH THROUGHOUT THE ENTIRE LAYER WITH 40-50 KNOT SOUTHERLY LOW LEVEL JET. IN THE MEANTIME...GUSTY SOUTHERLY WINDS OF 20 TO 25 KNOTS LIKELY TODAY. /CHAPMAN && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
337 PM MST SUN FEB 19 2012 .UPDATE... ISSUED AT 336 PM MST SUN FEB 19 2012 LATEST SHORT RANGE MODELS INDICATED ENERGY AND MOISTURE FOCUSED OVER SOUTHWEST COLORADO THROUGH THIS EVENING. SNOWFALL WAS ALREADY PERSISTENT AND HEAVY AT TIMES FROM KCEZ TO KDRO AND RUC13 AND NAM12 INDICATED THAT SNOW WILL CONTINUE THROUGH THE EVENING. BASED UPON AMOUNTS ALREADY REPORTED IN CONJUNCTION WITH AREA WEB CAMS... FELT WINTER WEATHER ADVISORY SHOULD BE ADDED TO THOSE AREAS FOR THE NEXT SEVERAL HOURS. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 150 PM MST SUN FEB 19 2012 MODELS CONTINUE TO ADVERTISE DEEPENING SHORTWAVE WHICH WILL MOVE ACROSS THE AREA OVERNIGHT. GOOD Q-G FORCING AND ADEQUATE MOISTURE OVERNIGHT WILL COMBINE TO GENERATE GOOD SNOW ACCUMULATIONS ACROSS MOST MOUNTAIN LOCATIONS AND NORTHERN AND CENTRAL VALLEYS. MODELS ARE ALSO SHOWING FAIRLY UNSTABLE LAPSE RATES THIS AFTERNOON AND EARLY EVENING WHICH WILL AID IN PRECIPITATION PRODUCTION AND MAY GENERATE SOME ISOLATED LIGHTNING OVER SOUTHERN HALF OF THE FORECAST AREA. BEHIND THE FRONT NORTHWEST FLOW WILL DOMINATE OVERNIGHT WITH NORTH TO WEST ASPECTS SEEING THE BEST ACCUMULATIONS WITH TEMPERATURES COOLING INTO THE FAVORABLE DENDRITIC GROWTH TEMPERATURE RANGE. HAVE DECIDED TO ADD DEBEQUE TO SILT CORRIDOR INCLUDING THE PLATEAU VALLEY TO THE WINTER WEATHER ADVISORY THROUGH TONIGHT. MODELS ARE HITTING THE GRAND MESA AREA THE HARDEST...LATER SHIFTS NEED TO MONITOR FOR POTENTIAL UPGRADE OF HIGHLIGHTS. EXPECT SNOWFALL TO DIMINISH FROM WEST TO EAST ACROSS THE LOWER VALLEY AFTER MIDNIGHT...AND END ACROSS MOUNTAIN LOCATIONS MONDAY MORNING. EXPECT LINGERING SNOW SHOWERS ESPECIALLY ALONG THE CONTINENTAL DIVIDE...OTHERWISE COLD TEMPERATURES WITH CLEARING SKIES ARE EXPECTED DURING THE DAY. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 150 AM MST SUN FEB 19 2012 MODELS CONTINUE TO SHOW AN UPPER RIDGE OFF THE WEST COAST WITH AN ASSOCIATED DOWNSTREAM TROUGH OVER THE WESTERN AND CENTRAL STATES THIS WEEK FOR GENERALLY NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL ROCKIES. AN EMBEDDED WAVE ZIPS SOUTHEAST ACROSS THE FORECAST AREA LATE MONDAY NIGHT AND TUESDAY FOR A CHANCE OF PRECIP. THE NORTHERN STREAM JET NOSES INTO NORTHERN CO TUE NIGHT...AND THEN VACILLATES BETWEEN WY AND CO THROUGH FRIDAY WHEN IT MOVES OFF TO THE EAST. THIS PATTERN SHOULD KEEP A PERSISTENT CHANCE OF SNOW FOR THE NORTHERN CO MTNS THROUGH FRIDAY...WITH THE BETTER CHANCES CURRENTLY LOOKING LIKE TUESDAY NIGHT AND THEN LATE WED NIGHT-THU. THESE ARE THE TIMES WHEN THE MODELS SHOW THE UPPER JET OVER NRN CO FOR ADDITIONAL FORCING ON TOP OF THE NORTHWEST OROGRAPHICS. THE CENTRAL MTNS WILL HAVE A LESSER CHANCE. MUCH OF EASTERN UT AND SOUTHWEST CO...IN CONTRAST... SHOULD EXPERIENCE LITTLE OR NO PRECIP WITH CLEAR OR PARTLY SKIES AND SEASONABLE TEMPS TUE THROUGH SAT. THIS COULD BE AN INTERESTING WEEK FOR THE NORTHERN CO MTNS...FROM VAIL NORTHWARD TO THE ELKHEAD AND PARK MTNS. THIS PATTERN OF PERSISTENT MOIST NW FLOW COULD LEAD TO AN EXTENDED PERIOD OF SNOW FOR THE NRN MTNS. WHILE SNOWFALL MAY NOT BE PARTICULARLY HEAVY FOR ANY PARTICULAR PERIOD...OVER TIME SIGNIFICANT ACCUMULATIONS ARE POSSIBLE. ADD TO THAT SOME GUSTY W TO NW MOUNTAIN WINDS AT TIMES AS THE JET WAVERS IN AN OUT OF NORTHERN CO. A PROGRESSIVE PATTERN CONTINUES NEXT WEEK WHEN ANOTHER PACIFIC TROUGH && .AVIATION...(FOR THE 21Z TAFS THROUGH 21Z MONDAY AFTERNOON) ISSUED AT 150 PM MST SUN FEB 19 2012 THE COLD FRONT ASSOCIATED WITH THIS STORM WILL MOVE THROUGH THE REMAINDER OF SOUTHEAST UTAH AND WESTERN COLORADO THROUGH THE EARLY EVENING HOURS TONIGHT. AHEAD OF THE FRONT EXPECT GUSTY SOUTHWEST WINDS FROM 15 TO 25 MPH WITH GUSTS TO 45 MPH OVER THE HIGHER TERRAIN...ESPECIALLY ON NORTH- FACING SLOPES AHEAD OF THE FRONT. WINDS WILL SHIFT TO THE NORTHWEST AND DECREASE BEHIND THE FRONTAL PASSAGE. GUSTY WINDS AHEAD OF THE FRONT WILL RESULT IN MODERATE MECHANICAL TURBULENCE IN THE VICINITY OF MOUNTAINS. SNOW WILL BECOME WIDESPREAD IN THE MOUNTAINS THIS EVENING AND CONTINUE OVERNIGHT RESULTING IN EXTENSIVE OBSCURATION. LOWER ELEVATION AIRPORTS ARE LIKELY TO EXPERIENCE MVFR CONDITIONS WITH AREAS OF IFR CONDITIONS THIS EVENING. MOUNTAIN AIRPORTS WILL SEE WIDESPREAD IFR CONDITIONS OVERNIGHT WITH SNOW DIMINISHING MONDAY MORNING. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER WEATHER ADVISORY UNTIL 8 AM MST MONDAY FOR COZ001>004-007- 009-010-012-013-017>019-023. WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ021- 022. UT...WINTER WEATHER ADVISORY UNTIL 8 AM MST MONDAY FOR UTZ023-025. WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR UTZ024. && $$ UPDATE...NL SHORT TERM...MPM LONG TERM....TGR AVIATION...MPM
AREA FORECAST DISCUSSION
NWS ALBANY NY
422 PM EST SUN FEB 19 2012 .SYNOPSIS...HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH THE REMAINDER OF THIS HOLIDAY WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL ON TUESDAY...AS THE HIGH SHIFTS OFF THE COAST...AND A WARM FRONT BRINGS A CHANCE OF RAIN OR SNOW SHOWERS TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... SOUTHEAST CONUS STORM CONTINUES TO TRACK EASTWARD AND WILL EXIT THE CAROLINA COAST THIS EVENING. A RATHER LARGE SURFACE HIGH THAT EXTENDS FROM EASTERN CANADA THROUGH THE GREAT LAKES REGION AND MID-LOWER MISSISSIPPI RIVER VALLEY WILL SLOWLY EDGE EAST TONIGHT. THE COMPLICATED FACTOR WILL BE THE PERSISTENT STRATOCU DOWNWIND OF LAKE ONTARIO THAT COVERS MOST OF UPSTATE NY /WEST OF THE HUDSON RIVER/. RUC13 SEEMS TO BE SLOWLY CAPTURING THIS LOW LEVEL MOISTURE THAT WANTS TO PERSIST A BIT LONGER. WE WILL FAVOR A PT-MOCLDY SKIES MAINLY WEST OF THE HUDSON THROUGH THIS EVENING WITH IMPROVEMENTS EXPECTED OVERNIGHT. MOS NUMBERS TONIGHT ARE VERY CLOSE TO OUR CURRENT OFFICIAL FORECAST SO LITTLE CHANGES NEEDED. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... BIG BUBBLE NO TROUBLE THROUGH TUESDAY AS SURFACE HIGH WILL BE IN FIRM CONTROL OVER THE EASTERN THIRD OF THE CONUS. WHILE THERMAL PROFILES ARE SLIGHTLY COOLER ON MONDAY...WITH AMPLE SUNSHINE AND LACK OF SNOW COVER...WE WILL FAVOR THE WARMER SIDE OF THE GUIDANCE ENVELOPE. THE SHORT WAVE TROUGH AXIS MIGRATING ACROSS THE FOUR CORNERS IS FORECAST TO EJECT OUT ONTO THE CENTRAL PLAINS MONDAY. THERE IS FAIRLY GOOD AGREEMENT WITH TRACKING THIS SYSTEM ACROSS THE MID MISSISSIPPI RIVER VALLEY EARLY TUESDAY THEN WEAKEN AS IT TRACKS OVER THE EASTERN GREAT LAKES REGION LATE IN THE DAY. THE COMBINATION OF DIFFUSE ISENTROPIC LIFT AND INCREASING LOW LEVEL JET DYNAMICS WILL ALLOW FOR CLOUDS TO INCREASE AND INTRODUCE THE CHANCE FOR PRECIPITATION TUESDAY NIGHT. BUFR PROFILES AND THICKNESS SCHEMES POINT TOWARD A RAIN/SNOW SHOWER MIXTURE DURING THE NIGHTTIME HOURS. FORECAST QPF VALUES ARE LIGHT WITH GENERALLY TWO TENTHS OF AN INCH OR LESS /THE HIGHER VALUES ACROSS THE FAVORABLE UPSLOPE TERRAIN LOCATIONS WITH THE SOUTHERLY FLOW/. MOS VALUES ARE IN GENERAL AGREEMENT BUT ONCE AGAIN WE WILL FAVOR THE WARMER SIDE DUE TO THE COMBINATION OF CLOUDS INCREASING...STRENGTHENING SOUTHERLY FLOW AND FAVORABLE GROUND CONDITIONS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... MOS GUIDANCE. A WEAK SURFACE LOW WILL BE TRACKING EAST ACROSS NEW YORK STATE AT THE START OF THE PERIOD. THIS WILL LIKELY RESULT IN LIGHT AMOUNTS OF MIXED PRECIPITATION WEDNESDAY NIGHT. ON ITS HEELS...ANOTHER LOW IS EXPECTED TO TRACK GENERALLY EAST ACROSS THE UPPER MIDWEST AND LIFT JUST WEST OF OUR AREA THURSDAY NIGHT. HOWEVER...THIS LOW IS EXPECTED TO INTENSIFY...PROVIDING GREATER QPFS. GIVEN THE TRACK AND EXPECTED INTENSIFICATION OF THE LOW... CAN`T RULE OUT THE POSSIBILITY OF A TRANSITION TO FREEZING RAIN AS THINGS SPIN UP THURSDAY NIGHT BUT GOOD WARM SURFACE ADVECTION GETTING INTO OUR AREA IS QUESTIONABLE AS IT/S MID-LEVEL DYNAMICS THAT APPEAR TO HAVE THE UPPER HAND. THE COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL PULL THROUGH ON FRIDAY...BUT THE MAIN COLD AIR BEHIND THE SYSTEM WILL HOLD BACK WITH A WEAK IMPULSE THAT WILL MOVE THROUGH FRIDAY NIGHT OR SATURDAY... POSSIBLY SETTING UP A LAKE EFFECT PATTERN FOR THE WEEKEND. THIS MEANS THAT THE SHOWERY DAYTIME ACTIVITY BEHIND THE SYSTEM ON FRIDAY WILL BE MAINLY IN THE FORM OF LIQUID OR A MIX...BEFORE COLD INFILTRATION TURNS IT BACK TO SNOW SHOWERS FRIDAY NIGHT AS IT WINDS DOWN BEFORE THE LAKE EFFECT MACHINE KICKS IN. SATURDAY WILL BE NOTICEABLY COLDER...WITH A NORTHWEST FLOW AND THE LAKE EFFECT ACTIVITY IN THE WESTERN ADIRONDACKS SATURDAY AND SATURDAY NIGHT. FROM LAKE GEORGE ON SOUTH...GOING NEAR ZERO POPS BUT DO HAVE SLT CHC POPS MOST OF THE REGION SUNDAY NIGHT. HIGH PRESSURE WILL BE STARTING TO BUILD IN FROM THE SOUTH DURING THAT TIME. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... VFR CONDITIONS WILL CONTINUE AT ALL TAF SITES THROUGH THE FORECAST PERIOD ENDING AT 18 UTC ON MONDAY. ASIDE FROM SOME DIURNAL CU/SC...SKIES WILL BE NEARLY CLEAR OVERNIGHT FOR ALL TAF SITES. SOME SCT PASSING HIGH CIRRUS MAY MOVE OVER KPOU TONIGHT DUE TO A STORM SYSTEM WELL TO THE SOUTH...OTHERWISE THE CLEAR SKIES WILL CONTINUE INTO THE OVERNIGHT HOURS FOR KGFL/KALB. A SHORTWAVE MOVING WELL NORTHEAST OF THE REGION ON MONDAY COULD ALLOW FOR A FEW STRAOCU/CU FOR KGFL FOR THE LATE MORNING TO AFTN HOURS ON MONDAY...OTHERWISE SKIES WILL CONTINUE NEARLY CLEAR AT THE OTHER SITES INTO THE WASHINGTON/S BIRTHDAY HOLIDAY. NORTHERLY WINDS WILL BE ABOUT 5-10 KTS THIS AFTN AND DIMINISH TO NEARLY CALM OVERNIGHT. WITHIN DAYTIME MIXING ON MONDAY...WINDS MAY ONCE AGAIN RETURN TO ABOUT 5-10 KTS FOR ALL TERMINALS FROM A NORTHERLY DIRECTION. OUTLOOK... MON NIGHT-TUE...VFR...NO SIG WX. TUE NGT...VFR/MVFR. CHC -SHRA/-SHSN. WED...MAINLY VFR. SLIGHT CHC -SHRA/-SHSN. WED NIGHT-THU...VFR/MVFR. CHC -SHRA/-SHSN. && .HYDROLOGY... NO HYDRO PROBLEMS ARE EXPECTED OVER THE NEXT 5 DAYS. DRY WEATHER WILL PERSIST UNTIL TUESDAY NIGHT...WHEN A FRONTAL BOUNDARY WILL BRING LIGHT PRECIPITATION IN THE FORM OF RAIN OR SNOW SHOWERS. A MORE WIDESPREAD AND HEAVIER PRECIPITATION SYSTEM MAY IMPACT THE HYDRO SERVICE AREA DURING THE SECOND HALF OF THE WEEK WITH SOME RAIN AND SNOW. THERE IS CONSIDERABLE UNCERTAINTY WITH THE EVOLUTION AND TRACK OF THIS LATER WEEK SYSTEM AT THIS TIME. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...BGM LONG TERM...ELH AVIATION...FRUGIS HYDROLOGY...BGM FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS ALBANY NY
408 PM EST SUN FEB 19 2012 .SYNOPSIS...HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH THE REMAINDER OF THIS HOLIDAY WEEKEND. TEMPERATURES WILL MODERATE BACK ABOVE NORMAL ON TUESDAY...AS THE HIGH SHIFTS OFF THE COAST...AND A WARM FRONT BRINGS A CHANCE OF RAIN OR SNOW SHOWERS TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... SOUTHEAST CONUS STORM CONTINUES TO TRACK EASTWARD AND WILL EXIT THE CAROLINA COAST THIS EVENING. A RATHER LARGE SURFACE HIGH THAT EXTENDS FROM EASTERN CANADA THROUGH THE GREAT LAKES REGION AND MID-LOWER MISSISSIPPI RIVER VALLEY WILL SLOWLY EDGE EAST TONIGHT. THE COMPLICATED FACTOR WILL BE THE PERSISTENT STRATOCU DOWNWIND OF LAKE ONTARIO THAT COVERS MOST OF UPSTATE NY /WEST OF THE HUDSON RIVER/. RUC13 SEEMS TO BE SLOWLY CAPTURING THIS LOW LEVEL MOISTURE THAT WANTS TO PERSIST A BIT LONGER. WE WILL FAVOR A PT-MOCLDY SKIES MAINLY WEST OF THE HUDSON THROUGH THIS EVENING WITH IMPROVEMENTS EXPECTED OVERNIGHT. MOS NUMBERS TONIGHT ARE VERY CLOSE TO OUR CURRENT OFFICIAL FORECAST SO LITTLE CHANGES NEEDED. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... BIG BUBBLE NO TROUBLE THROUGH TUESDAY AS SURFACE HIGH WILL BE IN FIRM CONTROL OVER THE EASTERN THIRD OF THE CONUS. WHILE THERMAL PROFILES ARE SLIGHTLY COOLER ON MONDAY...WITH AMPLE SUNSHINE AND LACK OF SNOW COVER...WE WILL FAVOR THE WARMER SIDE OF THE GUIDANCE ENVELOPE. THE SHORT WAVE TROUGH AXIS MIGRATING ACROSS THE FOUR CORNERS IS FORECAST TO EJECT OUT ONTO THE CENTRAL PLAINS MONDAY. THERE IS FAIRLY GOOD AGREEMENT WITH TRACKING THIS SYSTEM ACROSS THE MID MISSISSIPPI RIVER VALLEY EARLY TUESDAY THEN WEAKEN AS IT TRACKS OVER THE EASTERN GREAT LAKES REGION LATE IN THE DAY. THE COMBINATION OF DIFFUSE ISENTROPIC LIFT AND INCREASING LOW LEVEL JET DYNAMICS WILL ALLOW FOR CLOUDS TO INCREASE AND INTRODUCE THE CHANCE FOR PRECIPITATION TUESDAY NIGHT. BUFR PROFILES AND THICKNESS SCHEMES POINT TOWARD A RAIN/SNOW SHOWER MIXTURE DURING THE NIGHTTIME HOURS. FORECAST QPF VALUES ARE LIGHT WITH GENERALLY TWO TENTHS OF AN INCH OR LESS /THE HIGHER VALUES ACROSS THE FAVORABLE UPSLOPE TERRAIN LOCATIONS WITH THE SOUTHERLY FLOW/. MOS VALUES ARE IN GENERAL AGREEMENT BUT ONCE AGAIN WE WILL FAVOR THE WARMER SIDE DUE TO THE COMBINATION OF CLOUDS INCREASING...STRENGTHENING SOUTHERLY FLOW AND FAVORABLE GROUND CONDITIONS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... FORTHCOMING SHORTLY... && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... VFR CONDITIONS WILL CONTINUE AT ALL TAF SITES THROUGH THE FORECAST PERIOD ENDING AT 18 UTC ON MONDAY. ASIDE FROM SOME DIURNAL CU/SC...SKIES WILL BE NEARLY CLEAR OVERNIGHT FOR ALL TAF SITES. SOME SCT PASSING HIGH CIRRUS MAY MOVE OVER KPOU TONIGHT DUE TO A STORM SYSTEM WELL TO THE SOUTH...OTHERWISE THE CLEAR SKIES WILL CONTINUE INTO THE OVERNIGHT HOURS FOR KGFL/KALB. A SHORTWAVE MOVING WELL NORTHEAST OF THE REGION ON MONDAY COULD ALLOW FOR A FEW STRAOCU/CU FOR KGFL FOR THE LATE MORNING TO AFTN HOURS ON MONDAY...OTHERWISE SKIES WILL CONTINUE NEARLY CLEAR AT THE OTHER SITES INTO THE WASHINGTON/S BIRTHDAY HOLIDAY. NORTHERLY WINDS WILL BE ABOUT 5-10 KTS THIS AFTN AND DIMINISH TO NEARLY CALM OVERNIGHT. WITHIN DAYTIME MIXING ON MONDAY...WINDS MAY ONCE AGAIN RETURN TO ABOUT 5-10 KTS FOR ALL TERMINALS FROM A NORTHERLY DIRECTION. OUTLOOK... MON NIGHT-TUE...VFR...NO SIG WX. TUE NGT...VFR/MVFR. CHC -SHRA/-SHSN. WED...MAINLY VFR. SLIGHT CHC -SHRA/-SHSN. WED NIGHT-THU...VFR/MVFR. CHC -SHRA/-SHSN. && .HYDROLOGY... NO HYDRO PROBLEMS ARE EXPECTED OVER THE NEXT 5 DAYS. DRY WEATHER WILL PERSIST UNTIL TUESDAY NIGHT...WHEN A FRONTAL BOUNDARY WILL BRING LIGHT PRECIPITATION IN THE FORM OF RAIN OR SNOW SHOWERS. A MORE WIDESPREAD AND HEAVIER PRECIPITATION SYSTEM MAY IMPACT THE HYDRO SERVICE AREA DURING THE SECOND HALF OF THE WEEK WITH SOME RAIN AND SNOW. THERE IS CONSIDERABLE UNCERTAINTY WITH THE EVOLUTION AND TRACK OF THIS LATER WEEK SYSTEM AT THIS TIME. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...BGM LONG TERM...ELH AVIATION...FRUGIS HYDROLOGY...BGM FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1134 AM CST SUN FEB 19 2012 ...UPDATE TO AVIATION... .DISCUSSION... SHORT RANGE FORECAST (TODAY AND MONDAY)... EARLY MORNING 11 TO 3.9 MICRON SATELLITE IMAGERY INDICATES THAT ALL OF NORTHEAST KANSAS REMAINS UNDER MOSTLY CLEAR SKIES. 08Z WATER VAPOR IMAGERY AND THE ASSOCIATED RUC UPPER AIR ANALYSIS SHOWS A WEAK UPPER TROUGH MOVING EASTWARD INTO NORTHERN MISSOURI. THIS TROUGH WILL NOT HAVE MUCH AFFECT ON THE REGION THIS MORNING AS IT EXITS TO THE EAST. ALSO TO THE WEST...THE NEXT UPPER WAVE IS BEGINNING TO DIG INTO THE INTERIOR WESTERN US AND SHOULD BE CROSSING THE GREAT DIVIDE ON SUNDAY NIGHT. THIS WESTERN TROUGH WILL BE THE ONE TO WATCH AS WE HEAD INTO NEXT WEEK. BETWEEN THE TWO UPPER TROUGHS IS A SHORTWAVE RIDGE WHICH WILL MOVE OVER THE AREA FOR SUNDAY. SOUTHERLY WINDS WILL PICK UP THROUGHOUT THE DAY ON SUNDAY...WHICH IN COMBINATION WITH THE UPPER RIDGE SHOULD ALLOW TEMPS TO WARM UP A BIT FROM SATURDAY. EXPECT TEMPS TO RISE INTO THE LOWER 50S TODAY AS THE LOWER ATMOSPHERE SHOULD BE ABLE TO MIX TO AROUND 850 MB ON SUNDAY. SOUTHERLY WINDS WILL PERSIST THROUGH THE NIGHT AS THE SURFACE WAVE DEEPENS AS IT COMES OFF THE HIGH PLAINS. THE LASTING SOUTHERLY FETCH SHOULD ALLOW DECENT MOISTURE (FOR THIS TIME OF YEAR) TO RETURN INTO THE CENTRAL PLAINS. MODELS FOR A COUPLE DAYS HAVE HINTED AT LOWER TO MID 40 DEWPOINTS REACHING INTO NORTHEAST KANSAS IN ADVANCE OF THE NEXT TROUGH. TAKING A CUE FROM THE 00Z AND 06Z NAM HAVE INTRODUCED SOME THUNDER TO THE GOING FORECAST AS MODELS HAVE NOW INDICATED ENOUGH MOISTURE INFLUX AND STEEP ENOUGH MID LEVEL LAPSE RATES TO GENERATE UP TO 500-700 J/KG OF MUCAPE DURING THE DAY ON MONDAY. WITH THAT MUCH INSTABILITY IT SEEMS ALMOST LIKELY AT THIS POINT THAT THUNDERSTORMS WILL BE EMBEDDED WITHIN THE MONDAY RAIN SHIELD. ONCE THE MAIN UPPER WAVE ENTERS THE CENTRAL PLAINS ON MONDAY AFTERNOON/EVENING IT WOULD PROVIDE ENOUGH LIFT TO KICK OFF RAIN SHOWERS ACROSS THE ENTIRE FORECAST AREA. SURFACE AND LOW LEVEL WINDS SHOULD BE BACKED ON MONDAY AFTERNOON WHICH IN CONJUNCTION WITH S-SWLY FLOW IN THE LOW TO MID LEVELS WILL ALLOW FOR SOME TURNING IN THE ATMOSPHERE. WITH 0-6 SHEAR EXPECTED TO BE ON THE ORDER OF 40 TO 50 KNOTS...THE COMBINATION OF INSTABILITY WITH SHEAR MAY ALLOW FOR SOME ISOLATED STRONG THUNDERSTORMS WHICH WOULD ALSO BRING AN ISOLATED HAIL THREAT FOR MONDAY. ONCE THE SUN SETS ON MONDAY NIGHT THE INSTABILITY SHOULD WANE RAPIDLY...SO ANY LINGERING SHOWERS BEYOND 8 PM TO 9 PM ON MONDAY SHOULD BE LIGHT STRATIFORM RAIN AS OPPOSED TO THUNDERSTORMS. EXPECT PRECIP TO EXIT THE AREA COMPLETELY BY AROUND MIDNIGHT ON TUESDAY MORNING. MID RANGE AND EXTENDED FORECAST (TUESDAY THROUGH SATURDAY)... A RATHER MILD AND UNSEASONABLY WARM WEEK IS ON TAP ONCE THE RAIN SHOWERS EXIT ON TUESDAY MORNING. A RATHER PRONOUNCED DOWN SLOPE COMPONENT TO THE WINDS PRESENTS ITSELF FOR TUESDAY AND WEDNESDAY WHICH SHOULD AID IN WARMING TEMPS FOR THE MID TO LATE WEEK TIME PERIOD. BROAD UPPER WAVE THEN SLIDES SOUTHEASTWARD LATE IN THE WEEK...WHICH WILL BRING AN ISOLATED CHANCE FOR SOME PRECIP IN THE FAR NORTHEASTERN CORNER OF THE STATE. SURFACE HIGH THEN DROPS SOUTHWARD ON THURSDAY INTO FRIDAY...WHICH WILL BRING A COOLING TREND FOR THE LATE HALF OF THE WEEK. SINCE THE AIR MASS DOES NOT LOOK TO BE ARCTIC IN NATURE EXPECT TEMPERATURES TO REMAIN AT OR SLIGHTLY ABOVE SEASONAL NORMALS. JL .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && .AVIATION... VFR EXPECTED THROUGH 09Z AT THE TERMINAL SITES. MVFR CIGS ARE EXPECTED TO MOVE INTO THE THE MHK TERMINAL BY 12Z MONDAY. VFR EXPECTED AT TOP AND FOE THROUGH THE ENTIRE PERIOD. WINDS WILL INCREASE FROM THE SOUTHEAST TO SOUTH BY 13Z WITH WINDS NEAR 18KTS WITH GUSTS TO 28 KTS BY END OF PERIOD POSSIBLE. SHRA WILL DEVELOP AFTER 15Z AND ADDED VCSH TO MHK TAF ATTM. 53 && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
352 PM EST SUN FEB 19 2012 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 347 PM EST SUN FEB 19 2012 12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW WNW FLOW ALF OVER THE UPR LKS BTWN TROF IN QUEBEC AND UPR RDG MOVING E THRU THE PLAINS. SFC HI PRES RDG IS ORIENTED FM LOWER MI INTO SRN WI... BRINGING QUIET DAY TO THE CWA. EXCEPT FOR LINGERING SC E OF ERY TOWARD BACK EDGE OF SLOWLY DEPARTING H925 THERMAL TROF/A BIT MORE LLVL MSTR SHOWN ON THE 12Z APX RAOB...SKIES ARE GENERALLY SUNNY OVER THE CWA AS 12Z GRB/MPX/INL RAOBS DEPICT A DRY AIRMASS WITH PWAT 0.15 TO 0.20 INCH. THERE IS A SHRTWV DROPPING ESEWD OVER THE UPR LKS... BUT ONLY SOME HI CLDS MARK THE PRESENCE OF THIS FEATURE WITH DRY LO/ MID LVLS PRESENT. ALTHOUGH MIN TEMPS THIS MRNG FELL BLO ZERO AT A NUMBER OF INTERIOR LOCATIONS...THE BRIGHT SUNSHINE HAS HELPED THE MERCURY RECOVER TO WELL ABV NORMAL LEVELS THIS AFTN. FARTHER TO THE W...THERE IS A TROF IN THE ROCKIES. QUITE A BIT OF HI CLDS ARE STREAMING NEWD THRU THE PLAINS TOWARD MN IN THE SW FLOW ALF AHEAD OF THIS FEATURE. MAIN FCST CONCERNS IN THE SHORT TERM ARE TEMPS WITH HI PRES RDG EXPECTED TO DOMINATE. TNGT...UPR RDG IS FCST TO BUILD OVHD TNGT WITH DRY AIRMASS STILL DOMINATING. ANY LINGERING LO CLDS OVER THE FAR ERN CWA SHOULD BE GONE BY FCST ISSUANCE WITH WLY FLOW/WARMING AND DRYING AT H925. EXPECT THE LOWEST MIN TEMPS AOB THE LO END OF GUIDANCE OVER THE INTERIOR E AND SCNTRL UNDER WEAKER PRES GRADIENT/LIGHTER SW FLOW ARND HI PRES CENTERED OVER LOWER MI. ADDED SOME PATCHY FOG IN THESE AREAS OVER THE E WHERE SFC DEWPTS REMAIN FAIRLY HI AOA 20. A BIT STRONGER SW FLOW OVER THE NW HALF AND THE ARRIVAL OF SOME HI CLDS AHEAD OF THE SLOWLY PROGRESSIVE ROCKIES TROF WL LIMIT THE DIURNAL FALL OF TEMP IN THAT AREA A BIT. MON...EXPECT INCRSG SLY FLOW OVER UPR MI BTWN DEPARTING UPR RDG/SFC HI TO THE E AND APRCHG UPR TROF THRU THE PLAINS IN PROGRESSIVE PATTERN ALF. ALTHOUGH THERE WL BE QUITE A BIT OF HI CLD UNDER THE SW FLOW ALF...THE LO/MID LVLS WL REMAIN QUITE DRY. H85 TEMPS ARE FCST TO RISE CLOSE TO 0C OVER THE W BY LATE IN THE DAY...SO EXPECT A HEALTHY DIURNAL TEMP RECOVERY DESPITE THE HI CLD COVER. TEMPS ARE LIKELY TO BE HIEST IN THE DOWNSLOPE AREAS NEAR LK SUP FM IWD-COPPER HARBOR...BARAGA AND MQT. TEMPS ARE LIKELY TO REACH 40 OR BETTER IN THESE LOCATIONS. AREAS NEAR THE ICE ON THE BAY OF GREEN BAY WL BE COOLEST. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 347 PM EST SUN FEB 19 2012 SPLIT FLOW TO START THE PERIOD WITH STRONGER JET STREAM REMAINING IN THE SOUTHERN BRANCH. MODELS ARE IN PRETTY GOOD AGREEMENT WITH PLACEMENT OF THE TWO SHORTWAVE TROUGHS OVR CENTRAL CONUS INTO SOUTH CENTRAL CANADA ON MONDAY EVENING. UPR LEVEL WAVES STILL LOOK TO REMAIN SEPARATE INTO TUESDAY BUT H85 LOWS DO TRY TO MERGE TOGETHER OVR NW ONTARIO AND LK SUPERIOR REGION BY TUESDAY AFTN. RESULT IS A SW FLOW OF INCREASING MOISTURE INTO UPR MI LATER MONDAY NIGHT INTO TUESDAY. MORE ABUNDANT MOISTURE/HIGHER PWATS STAY TIED TO SOUTHERN STREAM UPR SYSTEM TRACKING ACROSS NORTHERN OHIO VALLEY INTO CNTRL GREAT LAKES. EXPECT SWATH OF SNOW FORCED BY DIVERGENCE FM UPR JET AND MID LEVEL FRONTOGENEIS TO LIFT INTO WESTERN UPR MI AFTER MIDNIGHT MONDAY NIGHT THROUGH MID MORNING ON TUESDAY. SNOW SHOULD FADE AWAY THROUGH THE DAY WHILE MOVING EAST AS MAIN MOISTURE STREAMS BEGIN TO SPLIT AROUND UPR MI. BEST CHANCE FOR ACCUMULATING SNOW WOULD BE IN THE FAR WESTERN CWA AROUND KIWD EARLY ON TUESDAY. DID OPT FOR MENTION OF RAIN ALONG IMMEDIATE LK MICHIGAN SHORE LATER ON TUESDAY WITH ONSHORE WINDS. KIND OF A TRICKY FCST BEYOND TUESDAY AT THIS POINT...ESPECIALLY THROUGH THURSDAY. MAIN ITEM CASTING UNCERTAINTY IS GENERAL TROUGHING STAYING PUT FM SCNTRL CANADA INTO UPR LAKES. INITALLY ON TUESDAY NIGHT...PRIMARY FOCUS FOR WIDESPREAD/STEADY PCPN SHOULD BE NORTH AND NORTHEAST OF UPR MI OVER ONTARIO/QUEBEC IN VCNTY OF SFC-H85 LOW. H85-H7 MOISTURE DOES LINGER THOUGH...ESPECIALLY OVR LK SUPERIOR. MOISTURE COMBINED WITH WESTERLY FLOW AND H85 TEMPS DOWN TO AROUND -10C COULD LEAD TO LGT SNOW SHOWERS ACROSS KEWEENAW. MINIMAL CHANGE INTO WEDNESDAY...AS WEST-NORTHWEST LOW-LEVEL WINDS PERSIST OVER THE AREA AS SFC LOW LIFTS INTO QUEBEC. UPR LAKES IS WITHIN BASE OF LARGER TROUGH...SO THERE COULD BE SOME SHORTWAVES SLIDING BY IN THE FLOW THAT ARE NOT DEPICTED IN THE MODELS RIGHT NOW. OVERALL...SEEMS LIKE SOME SMALL CHANCE POPS ARE JUSTIFIED...BUT NOTHING MORE AT THIS POINT. FOR THE EXTENDED...YESTERDAY IT LOOKED LIKE ONCE SFC-H85 LOWS WOULD TRACK INTO QUEBEC IT WOULD USHER IN NW FLOW LK EFFECT BY THURSDAY INTO FRIDAY. PATTERN LOOKING NOT AS CLEAR CUT NOW. MODELS... ESPECIALLY LATEST VERSIONS OF GFS AND CANADIAN...POINT TO STRONGER COMPACT LOW PRESSURE SYSTEM RIDING SOUTHERN EDGE OF THE TROUGH FM NORTHERN ROCKIES ACROSS THE NORTHERN PLAINS WEDNESDAY AND WEDNESDAY NIGHT AND INTO UPR GREAT LAKES THURSDAY/THURSDAY NIGHT. EARLIER THE GFS WAS FARTHEST NORTH WITH THE LOW/QPF THAN OTHER MODELS...BUT LATEST CANADIAN NOW TAKES THAT TITLE. ECMWF IS FARTHER SOUTH AND MORE SHEARED OUT WITH THE DISTURBANCE. BLEND OF MODELS AND THE GFS ENSEMBLE WOULD SUGGEST FAR SOUTH CWA SEES THE BEST CHANCE OF SNOW LATER WEDNESDAY NIGHT INTO THURSDAY. DETAILS ARE FAR FM SET THOUGH. GIVEN UNCERTAINTY WILL STEER AWAY FM LK EFFECT POP IDEA FOR THURSDAY AND OPEN UP MOST OF CWA FOR LOW CHANCE POPS. MOST MODELS INDICATE LOW-LEVEL WINDS OVR NOTHERN CWA WOULD BE FM THE NORTH OR NORTHEAST THURSDAY/THURSDAY NIGHT WITH AT LEAST SUFFICIENT LOW-LEVEL MOISTURE. INSTABILITY WOULD BE MARGINAL WITH DELTA T/S ONLY UP TO 13C. IF THE LOW PRESSURE DOES TRACK FARTHER NORTH...THEN THERE WOULD BE MORE POTENTIAL OF LAKE ENHANCEMENT. EVENTUALLY...EXPECT NW FLOW LK EFFECT TO DEVELOP OVR THE AREA IN WAKE OF THIS SYSTEM LATER THURSDAY NIGHT INTO FRIDAY AND ON INTO SATURDAY AS WELL. H85-H7 DEEPER MOISTURE ALONG WITH SUFFICIENT OVER-WATER INSTABILITY MAY SUPPORT SOME MODERATE ACCUMS IN THE THURSDAY NIGHT/FRIDAY TIME FRAME. COLDEST DAYS OVR THE CWA SHOULD BE FRIDAY AND SATURDAY...WITH HIGHS STAYING IN THE TEENS FOR SOME OF THE AREA. SUFFICIENTLY COLD AIR /H85 TEMPS BLO -15C/ PERSISTS INTO SATURDAY THOUGH DECREASING SUB H85 MOISTURE AND LOWERING INVERSIONS WITH ARRIVAL OF SFC-H85 RIDGE SHOULD BEGIN TO PUT DENT IN THE LK EFFECT. UNCERTAINTY BACK INTO FCST BY SUNDAY AS GFS AND PREVIOUS ECMWF WERE OUT OF PHASE WITH EACH OTHER. LATEST ECMWF IS MORE IN LINE WITH GFS IDEA THOUGH SUGGESTING SYSTEM SNOW COULD RETURN TO UPR LAKES LATE NEXT WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1223 PM EST SUN FEB 19 2012 EXPECT VFR CONDITIONS THIS FCST PERIOD WITH DRY HI PRES DOMINATING. A STRONGER S WIND WILL DEVELOP ON MON UNDER SHARPENING PRES GRADIENT BTWN DEPARTING HI PRES AND LO PRES APRCHG FM THE PLAINS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 347 PM EST SUN FEB 19 2012 WITH AN UNSEASONABLY WEAK PRES GRADIENT FORECAST INTO TUE...EXPECT WINDS NO HIER THAN 25 KTS. A STRONGER W WIND TO 30 KTS IS POSSIBLE TUE NIGHT AND WED ON THE SOUTHERN FLANK OF LO PRES CROSSING ONTARIO. THERE MAY BE SOME GALE FORCE GUSTS OVER PORTIONS OF NCENTRAL AND EASTERN LK SUP. MAINLY NORTH TO NORTHWEST WINDS LESS THAN 30 KTS EXPECTED LATE THIS WEEK AS COLDER AIR RETURNS TO THE REGION. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...JLA AVIATION...KC MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS HASTINGS NE
418 PM CST SUN FEB 19 2012 .SHORT TERM...TONIGHT AND MONDAY. PRIMARY FORECAST CONCERN LIES WITH PRECIPITATION CHANCES. BEEN A QUIET DAY TODAY...WITH UPPER AIR PROFILER AND SATELLITE DATA SHOWING THE REGION REMAINING UNDER THE INFLUENCE OF SHORTWAVE RIDGING...BETWEEN A TROUGH OVER THE MIDWEST AND ANOTHER TROUGH DIGGING INTO THE DESERT SOUTHWEST. WINDS HAVE GRADUALLY BECOME MORE SOUTHERLY AND INCREASED IN SPEED THROUGH THE DAY...THANKS TO DEVELOPING LOW PRESSURE OVER THE ROCKIES AND HIGH PRESSURE EXTENDING THROUGH THE GREAT LAKES AND DOWN TOWARD ERN TX. THAT BAND OF LOW LEVEL STRATUS DRAPED FROM NRN NEB SOUTH INTO TX DID DRIFT A TOUCH FURTHER EAST EARLIER THIS AFTERNOON...AND HAS STALLED OUT WITH SATELLITE IMAGERY SHOWING IT SHRINKING IN SIZE...BUT STILL KEEPING WRN AREAS MOSTLY CLOUDY. LOOKING TO TONIGHT AND TOMORROW...THE MAIN STORY REMAINS WITH THAT TROUGH DIGGING INTO THE DESERT SOUTHWEST AND ITS EVENTUAL ARRIVAL ONTO THE PLAINS. OVERNIGHT...MODELS IN PRETTY GOOD AGREEMENT SHOWING A CLOSED CIRCULATION DEVELOPING WHILE SHIFTING EAST...AND BY 12Z TOMORROW...THE 500MB LOW LOOKS TO BE CENTERED OVER CENTRAL/ERN COLORADO...WITH THE 700MB LOW A TOUCH FURTHER NEAST. AHEAD OF THIS SYSTEM...SFC LOW PRESSURE CONTINUES TO BECOME BETTER ORGANIZED AND DRIFTS NEAR THE CO/KS/NEB BORDER AREA BY 12Z TOMORROW...BRINGING INCREASED S/SERLY WINDS TO THE CWA OVERNIGHT. ALONG WITH THE WINDS...EXPECTING TO SEE INCREASED ISENTROPIC LIFT...AS WELL AS INCREASED WARM AIR/MOISTURE ADVECTION...WITH MODELS IN GOOD AGREEMENT SHOWING A SRLY LLJ CRANKING UP /45 TO NEAR 60 KTS DEPENDING ON THE MODEL/. THIS IS EXPECTING TO RESULT IN INCREASED PRECIPITATION CHANCES ACROSS THE CWA...MAINLY AFTER MIDNIGHT AND ACROSS THE NORTHEASTERN 2/3RDS OF THE CWA. KEPT THE MENTION OF ISOLATED THUNDER GOING IN THE FORECAST WITH MODELS IN DECENT AGREEMENT SHOWING SOME INSTABILITY PRESENT...THE NAM IS CERTAINLY THE MORE AGGRESSIVE OF THE MODELS SHOWING A 1-2 J/KG IN SOME AREAS...WITH OTHER MODELS LESS THAN 100 J/KG. THINK THAT OVERNIGHT LOWS WILL COME EARLIER ON IN THE NIGHT...THAT INCREASING CLOUD COVER AND S/SERLY WINDS WILL HELP TO STEADY OUT TEMPS...AND BY THE TIME PRECIPITATION CHANCES INCREASE THE TEMPS ARE EXPECTED TO BE ABOVE FREEZING...BUT NOT BY MUCH...ESP IN SOME NEAST LOCATIONS. AS WE GET INTO TOMORROW...MODELS REMAIN IN PRETTY GOOD AGREEMENT WITH THE MAIN SYSTEM...SHOWING THE LOW SHIFTING BASICALLY STRAIGHT EAST RIGHT INTO OUR NC KS COUNTIES BY 00Z. MAIN CHANGE MADE TO THE FORECAST WAS TO SHOW A NORTHWARD SHIFT OF THE MORNING PRECIPITATION CHANCES AS THE NOSE OF THE LLJ CONTINUES PUSHING NORTH AND DRIER MID LEVEL AIR WORKS ITS WAY IN FROM THE SOUTH. HAVE THUNDERSTORM MENTION DIMINISHING IN THE MORNING...AND THEN LOWERED POPS A BIT AND HAVE THE POTENTIAL FOR DRIZZLE WORKING ITS WAY IN FROM S TO N ACROSS THE ENTIRE CWA. THEN PRECIPITATION CHANCES PICK UP AGAIN DURING THE AFTERNOON HOURS AS THE SYSTEM SHIFTS CLOSER. THROUGH THE AFTERNOON HOURS...MODELS SHOWING THE SFC/UPPER LEVEL LOWS MOVING INTO NC KS...WITH A COLD FRONT STARTING TO MOVE INTO WRN PORTIONS OF THE CWA...AND SOME DRIER AIR SHIFTING IN FROM THE SOUTH. ON THE BACKSIDE OF THE SYSTEM ACROSS THE NW PORTION OF THE CWA...COULD START TO SEE A MIX OF RA/SN AS COOLER AIR STARTS TO WORK IN...BUT NOT EXPECTING MUCH SN ACCUMULATION. ACROSS THE REMAINDER OF THE CWA...AND ESP THE SERN THIRD OR SO...PTYPE REMAINS LIQUID...AND THE POSSIBILITY OF THUNDERSTORMS RETURNS. MODELS IN GOOD AGREEMENT SHOWING INCREASED LOW/MID LEVEL LAPSE RATES /500MB TEMPS NEAR -30C/ DURING THE AFTERNOON. AGAIN THE NAM IS THE MOST AGGRESSIVE WITH THINGS...EVEN SHOWING INSTABILITY APPROACHING 900 J/KG...WITH OTHER MODELS NOT REALLY EVEN CLOSE TO THAT...MORE ON THE ORDER OF 1-200 J/KG OR SO. AM SIDING WITH THE LOWER VALUES WHICH HAS MORE SUPPORT. WITH THE SYSTEM PASSING RIGHT THROUGH NC KS...SOME INSTABILITY AND STEEPER LAPSE RATES PRESENT...AT LEAST SOME ISOLATED THUNDERSTORMS ARE POSSIBLE...AND CANT COMPLETELY RULE OUT A STRONGER CELL OR TWO DROPPING SOME SMALL HAIL...AND WILL MENTION IN THE HWO. TEMPERATURES ARE TRICKY...AM EXPECTING PLENTY OF CLOUD COVER TO BE PRESENT...BUT IF SOME AREAS MANAGE TO SEE MORE SUN /MAINLY THE SOUTH/...FORECAST HIGHS ARE LIKELY TOO LOW. CURRENTLY CALLING FOR UPPER 30S IN THE NW TO UPPER 40S IN THE SE. AS FAR AS WINDS GO...WITH THE FRONT PASSING THROUGH...DIRECTION WILL BE TRANSITIONING FROM THE S/SE TO THE NW...AND THROUGH THE MID/LATE AFTERNOON HOURS...WRN AREAS BEHIND THAT FRONT COULD BE FAIRLY GUSTY AT TIMES. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY. WILL HAVE TO WATCH OUT FOR SOME RAIN MIXED WITH SNOW MONDAY EVENING AND THEN WE CAN EXPECT FAIRLY DRY CONDITIONS THEREAFTER...ALTHOUGH A FEW VERY LIGHT PRECIPITATION EVENTS CAN NOT BE RULED OUT. MONDAYS STORM SYSTEM WILL BE ON ITS WAY OUT OF THE REGION MONDAY EVENING...BUT RAIN COULD MIX WITH OR TURN OVER TO SNOW DURING THE EVENING HOURS ON THE BACK SIDE OF THE SYSTEM. COLDER AIR WILL FUNNEL IN BEHIND THE SFC LOW MAKING A BRIEF CHANGE OVER TO SNOW POSSIBLE. HOWEVER...EVEN IF RAIN CAN CHANGE OVER TO SNOW PRIOR TO ENDING...IT LIKELY WILL NOT LAST LONG DUE TO THE VERY PROGRESSIVE NATURE OF THIS SYSTEM. CONSEQUENTLY...LITTLE TO NO SNOWFALL ACCUMULATION IS EXPECTED AT THIS TIME FOR MOST AREAS. TUESDAY...TEMPERATURES WILL BE QUICK TO MODERATE TUESDAY AFTERNOON WITH DOWNSLOPE WESTERLY WINDS HELPING HIGH TEMPERATURES CLIMB INTO THE 40S ACROSS NEBRASKA WITH 50S OVER NORTHERN KANSAS. WEDNESDAY WILL CONTINUE TO BE A DRY DAY WITH PERSISTENT WESTERLY DOWNSLOPE WINDS PUSHING HIGHS INTO THE UPPER 40S TO AROUND 50 OVER SOUTHERN NEBRASKA...TO THE UPPER 50S TO AROUND 60 ACROSS NORTHERN KANSAS. WEDNESDAY NIGHT INTO THURSDAY...A COLD FRONT WILL PUSH THROUGH WEDNESDAY NIGHT INTO THURSDAY AND MAY RESULT IN TRACE AMOUNTS OF RAIN OR SNOW...BUT MOST AREAS WILL REMAIN DRY. HIGH TEMPERATURES ON THURSDAY SHOULD COOL BACK INTO THE 40S. FRIDAY THROUGH SUNDAY...OVERALL FLOW PATTERN REMAINS PROGRESSIVE WITH SEASONAL TEMPERATURES EXPECTED. WILL KEEP THINGS DRY FOR NOW..BUT WILL NEED TO WATCH FOR THE POSSIBLE DEVELOPMENT OF A STORM SYSTEM ACROSS THE WESTERN CONUS BY SUNDAY. AT THIS TIME...IT SEEMS THAT SHOULD THIS STORM DEVELOP IT WOULD STILL NOT ARRIVE IN THE PLAINS REGION UNTIL MONDAY. && .AVIATION...18Z TAF. PRIMARY FORECAST CONCERNS FOR THIS TAF PERIOD LIE WITH THE IMPACT OF ONGOING STRATUS AND PRECIPITATION CHANCES LATER IN THE PERIOD. BAND OF LOW LEVEL STRATUS EXTENDING FROM TX NORTH THROUGH NEB HAS CONTINUED TO GRADUALLY SHIFT EAST THIS MORNING...AND THE TERMINAL CURRENTLY SITTING RIGHT OUTSIDE ITS EASTERN FRINGE. RUC SEEMS TO BE DOING THE BEST JOB WITH WHAT HAS BEEN GOING ON...AND WITH IT SHOWING THIS CLOUD COVER EVEN GOING A BIT FURTHER EAST...WILL PUT MVFR CIGS IN THE TAF THROUGH MID AFTERNOON. IT IS POSSIBLE THE TERMINAL WILL REMAIN ON THE FRINGE AND HAVE SCT INSTEAD OF BROKEN CIGS...WILL MONITOR AND ADJUST ACCORDINGLY. FOCUS THEN TURNS TO OVERNIGHT/INTO MONDAY MORNING...AS AN UPPER LEVEL SYSTEM MOVES OUT OF THE ROCKIES. LOOKS LIKE THE BETTER CHANCES FOR PRECIPITATION AT THE TERMINAL WILL COME BETWEEN ROUGHLY 10-15Z...AND WITH A STRONG LLJ AND SOME INSTABILITY...KEPT THE CB MENTION GOING WITH SHOWERS. NOT CONFIDENT ENOUGH IN THE TERMINAL SEEING A TS TO PUT AS PREVAILING. FOR MID/LATE MORNING...BETTER CHANCES LOOK TO SHIFT NORTH WITH POTENTIAL FOR DZ BUILDING IN. START THE MORE DETERIORATING CIGS ALREADY AT MIDNIGHT AND CONTINUE THROUGH THE REMAINDER OF THE TAF PERIOD WITH VISIBILITIES DROPPING WITH THE ONSET OF PRECIPITATION. WITH THE MAIN SURFACE REMAINING W/SW OF THE TERMINAL...WINDS CONTINUE OUT OF THE SOUTH...EVENTUALLY BECOMING MORE SE WITH TIME. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT/AVIATION...ADO LONG...WESELY
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1240 PM EST SUN FEB 19 2012 .SYNOPSIS... LOW PRESSURE WILL APPROACH FROM THE SOUTHWEST AND MOVE NORTHEAST ALONG THE COAST LATE TODAY AND TONIGHT. HIGH PRESSURE WILL BUILD IN FROM THE WEST LATE MONDAY INTO TUESDAY. A COLD FRONT WILL APPROACH FROM THE WEST WEDNESDAY. && .NEAR TERM /THROUGH MONDAY/... AS OF 1235 PM SUNDAY...RAIN FILLING BACK IN OVER THE REGION WITH SOME HEAVIER SHOWERS INDICATED JUST SOUTH OF THE SOUTHERN COASTAL COUNTIES AND EVEN SOME THUNDER OFFSHORE. THIS IS IN RESPONSE TO MID-LEVEL JET MAX MOVING NORTHEAST FROM SOUTH CAROLINA. DESPITE SOME BREAKS IN THE RAINFALL...KEPT POPS IN THE CATEGORICAL RANGE FOR THE AFTERNOON. TEMPERATURES ARE LOCKED IN THE 40S TO LOWER 50S AND EXPECT LITTLE CHANGE THRU THE AFTERNOON GIVEN CLOUDS AND PRECIPITATION. && .SHORT TERM /MONDAY NIGHT/... AS OF 700 AM SUNDAY...LOW PRESSURE EXITS THE COAST WITH VERY WIND CONDITIONS THIS EVENING FOR PORTIONS OF THE ALBEMARLE COUNTIES...COUNTIES ADJACENT TO THE PAMLICO SOUND...AND THE OBX WHERE WIND ADVISORIES HAVE BEEN POSTED FOR LATE THIS EVENING THROUGH MON. A STRONG MID-LEVEL SHORTWAVE TROF DIVES SOUTH WITH COLDER AIR SURGING SOUTH AND WRAP AROUND MOISTURE LEADING TO RAIN CHANGING TO SNOW AFTER MIDNIGHT AND CONTINUING INTO MONDAY MORNING...MAINLY OVER THE NORTHEASTERN COUNTIES/NORTHERN OUTER BANKS REGION. THICKNESS VALUES SUPPORT A RAIN/SNOW MIX INITIALLY WITH A CHANGE TO ALL SNOW AFTER ABOUT 08Z OR SO. ANY SNOWFALL AMOUNTS AND HAVE CONTINUED WITH JUST 0.1 TO 0.4 INCH OVER THE NORTHERN OUTER BANKS AND AREAS ADJACENT TO THE ALBEMARLE SOUND THUS WILL NOT ISSUE A WINTER WEATHER ADVISORY ON THIS SHIFT. WITH WARM GROUND TEMPS DON`T EXPECT SIG ACCUMULATIONS AT THIS TIME. HOWEVER...THIS WILL CONT TO BE MONITORED BY FUTURE SHIFTS. TEMPS LOWER INTO THE MID 30S INLAND AND LOWER TO MID 40S IMMEDIATE COAST TONIGHT. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 AM SUN...ONLY MINOR CHANGES TO PREVIOUS FCST DURING PERIOD. DEEPENING LOW PRES WILL BE ABOUT 300 MILES ENE OF HAT AT BEGINNING OF PERIOD WITH MODERATE ARCTIC HIGH PRES BUILDING IN BEHIND IT WITH STRONG WINDS CONTINUING OVER COASTAL SECTIONS. LINGERING THREAT OF SNOW SHOWERS WITH SECONDARY SHRT WV TROF WILL END BY MID MORNING. CLEARING SKIES AND DIMINISHING WINDS REST OF DAY WITH HIGH PRES CENTER BUILDING IN. BELOW NORMAL TEMPS EXPECTED MON NIGHT WITH HIGH CENTER OVERHEAD...THEN A QUICK WARM-UP TUE WITH HIGH QUICKLY MOVING OFFSHORE AS NEXT SHRT WV TROF APPROACHES. 00Z MODELS HAVE TRENDED TO SOME LIGHT QPF ALONG COASTAL SECTIONS TUE AFTN WITH RETURN SRLY FLOW BUT APPEAR OVERDONE WITH EXPECTED STABLE CONDITIONS OVER COLDER NEAR SHORT WATERS...THUS NOT ENOUGH CONFIDENCE TO ADD POPS AT THIS TIME. MAINLY ZONAL FLOW ALOFT AND SEVERAL SHRT WVS AND ASSCTD FRONTS WILL AFFECT AREA WED-THU WITH LATEST MODELS INDICATING PCPN THREAT REMAINING MAINLY N AND S OF AREA BUT LEFT PREVIOUS FCST LOW CHC POPS. DEEPER SHRT WV TROF AND SFC FRONT WILL MOVE THROUGH LATE FRI FOLLOWED BY COOLER AIR MASS FOR NEXT WEEKEND. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... SHORT TERM /06Z SUNDAY THROUGH 06Z MONDAY/... AS OF 1240 PM SUNDAY...IFR CONDITIONS ARE LIKELY THRU THE OVERNIGHT HOURS AS PRECIPITATION CONTINUES TO OVERSPREAD THE REGION. ADDED A MIX OF RAIN AND SNOW AT PGV AS COLDER AIR FILTERS IN WITH A MIX LIKELY AFTER MIDNIGHT TONIGHT. LONG TERM /06Z MONDAY THROUGH THURSDAY/... AS OF 3 AM SUN...CIGS AND VSBYS WILL GRADUALLY IMPROVE TO VFR 09Z-12Z MON...WITH CLEARING EXPECTED 12Z-15Z. GUSTY NORTHERLY WINDS WILL CONTINUE THROUGH MORNING...THEN DIMINISH DURING AFTN. VFR CONDITIONS WILL PREVAIL REST OF PERIOD WITH ONLY MINIMAL THREAT OF PCPN WITH SERIES OF WEAK SHRT WVS AND SFC FRONTS. && .MARINE... SHORT TERM /TODAY AND TONIGHT/ AS OF 1240 PM SUNDAY...WINDS STARTING TO RAMP UP OVER THE PAST FEW HOURS WITH GUSTS TO 30 KNOTS NOW OBSERVED AT DUCK WITH SEAS BUILDING TO 7 FEET. RUC13 HAS THE BEST DEPICTION AND HAVE FOLLOWED THAT FOR THE NEAR TERM. WHILE THERE MAY BE A BRIEF LULL IN THE WIND AS THE SURFACE LOW APPROACHES...WILL NOT INDICATE IN TEXT AS WINDS SHOULD INCREASE TO GALE FORCE TONIGHT. NORTH WINDS TO INCREASE TO 25 TO 35 KNOTS WITH 30 TO 40 KNOTS ALONG THE NORTHERN WATERS TONIGHT INTO MONDAY. THE PEAK WINDS WILL OCCUR FROM 06Z TO ABOUT 14Z MONDAY. THE GUSTY NLY WINDS WILL LEAD TO ELEVATED WATER LEVELS FROM JUST N OF THE HATTERAS AREA TO CEDAR ISLAND AND OVER SOUTHERN PAMLICO SOUND. A COASTAL FLOOD ADVISORY REMAINS IN EFFECT FOR WATER LEVELS OF 1 TO 2 FEET ABOVE NORMAL WITH SOME LOCALIZED AREAS AT 3 FEET ABOVE NORMAL FOR TONIGHT AND MONDAY. SEAS PEAK AT 7 TO 12 FEET...MAINLY OVER NORTHERN AND CENTRAL COASTAL WATERS TONIGHT AND MONDAY. LONG TERM /MONDAY THROUGH THURSDAY/... AS OF 3 AM SUN...NO SIGNIFICANT CHANGES TO PREVIOUS FCST DURING PERIOD. ONGOING GALE EVENT ALL WATERS WILL GRADUALLY WEAKEN MONDAY AS HIGH PRES BUILDS IN FROM W AND LOW PRES MOVES FARTHER OFFSHORE. WINDS WILL CONTINUE DECREASING MON NIGHT WITH HIGH CENTER BUILDING OVER AREA...THEN QUICKLY BECOME SE-S TUE AS HIGH MOVES OFFSHORE. SERIES OF WEAK FRONTS WILL AFFECT AREA WED-THU WITH MODERATE SW WINDS. STRONGER FRONT WILL APPROACH LATE THU WITH SCA CONDITIONS PSBL AGAIN. WW3 AND SWAN IN GENERAL AGREEMENT ON SEAS AND ALSO WITH PREVIOUS FCST. HEIGHTS UP TO 12 FEET EXPECTED NRN AND CENTRAL WATERS EARLY MON...THEN GRADUALLY SUBSIDING INTO TUE BUT RESIDUAL SWELL WILL LIKELY KEEP AROUND 6 FT OVER OUTER PORTIONS OF NRN AND CENTRAL WATERS INTO TUE NIGHT. SEAS BUILDING AGAIN LATE THU WITH INCREASING SW WINDS AHEAD OF NEXT STRONG FRONT. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...WIND ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST MONDAY FOR NCZ103-104. COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST MONDAY FOR NCZ093-095-103-104. WIND ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST MONDAY FOR NCZ046-047-081-095. HIGH SURF ADVISORY FROM 10 PM THIS EVENING TO 10 PM EST MONDAY FOR NCZ103. MARINE...GALE WARNING FROM 10 PM THIS EVENING TO 5 PM EST MONDAY FOR AMZ130-135-150-152-154-156-158. && $$ SYNOPSIS...JBM NEAR TERM...CTC SHORT TERM...JBM LONG TERM...CQD AVIATION...CTC/CQD MARINE...CTC/JAC