Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/23/15


AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1126 PM CST FRI FEB 20 2015 .AVIATION... MAINLY MVFR CEILINGS WITH PATCHY IFR CEILINGS WILL BE SEEN OVER NORTHERN AND CENTRAL AREAS...WHILE VFR CEILINGS WITH PATCHY MVFR CEILINGS OVER SOUTHERN AREAS WILL BE SEEN OVERNIGHT. AREAS OF RAIN AND SHOWERS WILL BE SEEN OVER SOUTH AND CENTRAL AR...WHILE FREEZING PRECIP OVER NORTH CENTRAL TO NORTHERN AR. OVERNIGHT...A SLOW WARMING TREND WILL SPREAD OVER ALL OF AR...AND ANY FREEZING RAIN WILL CHANGE OVER TO RAIN. WINDS WILL BE E TO SE AT 5 TO 15 MPH TONIGHT...THEN GRADUALLY BECOME SE TO S TOWARD SATURDAY AM. LOW LEVEL WIND SHEAR WILL BE PRESENT AS A SOUTH LOW LEVEL JET FORMS OVER AR. A COLD FRONT WILL ALSO SLOWLY MOVE THROUGH AR ON SATURDAY AND BRING ISOLATED THUNDER TO THE AREA. && .PREV DISCUSSION... /ISSUED 616 PM CST FRI FEB 20 2015/ UPDATE... WENT AND EXTENDED THE WINTER WEATHER ADVISORY THROUGH MIDNIGHT. TEMPERATURES HAVE BEEN SLOW TO WARM THROUGH THE AFTERNOON AND EVENING. 12Z WRF AND HRRR SEEM TO HAVE A DECENT JOB WITH TEMPERATURE TRENDS THROUGH THE EVENING WITH MOST LOCATIONS ACROSS NORTHERN ARKANSAS NOT WARMING UP TO FREEZING UNTIL CLOSE TO 6Z. PREV DISCUSSION... /ISSUED 600 PM CST FRI FEB 20 2015/ AVIATION... AREAS OF VFR AND MVFR CEILINGS WILL BE SEEN THIS EVENING AND OVERNIGHT. MORE MVFR CEILINGS WITH PATCHY IFR CONDITIONS WILL DEVELOP OVERNIGHT. AREAS OF RAIN AND SHOWERS WILL BE SEEN OVER SOUTH AND CENTRAL AR...WHILE FREEZING PRECIP OVER NORTH CENTRAL TO NORTHERN AR. THROUGH THE EVENING AND OVERNIGHT...WARM AIR WILL GRADUALLY SPREAD INTO ALL OF AR...AND ANY FREEZING RAIN WILL CHANGE OVER TO RAIN. WINDS WILL BE E TO SE AT 5 TO 15 MPH THIS EVENING AND TONIGHT...BECOMING SE TO S TOWARD SATURDAY AM. LOW LEVEL WIND SHEAR WILL DEVELOP TONIGHT AS A SOUTH LOW LEVEL JET FORMS AND MOVES INTO AR. A COLD FRONT WILL ALSO SLOWLY MOVE THROUGH AR ON SATURDAY AND BRING ISOLATED THUNDER TO THE AREA. (59) PREV DISCUSSION... /ISSUED 240 PM CST FRI FEB 20 2015 SHORT TERM...TONIGHT THROUGH MONDAY NIGHT SURFACE OBSERVATIONS SHOW WARM AIR MOVING IN TO SOUTHWEST ARKANSAS AT THIS TIME. MOST AREAS IN THE CENTRAL AND SOUTHWEST ARE ABOVE FREEZING...AND TEMPERATURES WILL CONTINUE TO RISE THROUGH THE NIGHTTIME HOURS. AS AN UPPER WAVE MOVES INTO ARKANSAS TONIGHT...AND APPROACHING LOW PRESSURE PUSHES A WARM FRONT FURTHER INTO THE STATE...PRECIPITATION WILL BECOME WIDESPREAD. WITH TEMPERATURES WARMING...ALL AREAS SHOULD BE ABOVE FREEZING AFTER MIDNIGHT. HAVE GONE AHEAD AND READJUSTED THE WINTER STORM WARNING TO EXPIRE AT MIDNIGHT. WHILE MOST AREAS WILL NOT REACH WARNING CRITERIA...PREFER TO LEAVE IT IN PLACE DUE TO ISSUES NOTED TODAY. WILL ALLOW THE WINTER WEATHER ADVISORIES TO EXPIRE AT THEIR APPROPRIATE TIMES... AS ANY ADDITIONAL WINTRY PRECIPITATION WILL BE INCONSEQUENTIAL. THE AFOREMENTIONED LOW WILL DRAG A COLD FRONT ACROSS THE REGION ON SATURDAY. WITH ELEVATED INSTABILITY PRESENT...THUNDERSTORMS WILL BE POSSIBLE. TEMPERATURES WILL FALL BEHIND THE FRONT. ON SATURDAY NIGHT...PRECIPITATION WILL SHIFT EAST OF THE REGION AS ARCTIC AIR MOVES BACK IN. ON SUNDAY...THE NORTH WILL STRUGGLE TO GET TO FREEZING...WHILE THE CENTRAL AND SOUTH WILL STRUGGLE TO REACH THE 40S. ON SUNDAY NIGHT THROUGH MONDAY NIGHT...SEVERAL UPPER WAVES WILL MOVE THROUGH THE REGION. WITH ARCTIC AIR BACK IN PLACE...MOST PRECIPITATION THAT FALLS WILL BE IN THE FORM OF SNOW...WITH THE EXCEPTION OF THE FAR SOUTH...WHICH WOULD BE A MIX. WHILE IT DOESN/T LOOK HEAVY...IT MAY BE ENOUGH TO LIGHTLY ACCUMULATE...PARTICULARLY OVER WESTERN AND CENTRAL ARKANSAS. STAY TUNED. LONG TERM...TUESDAY THROUGH FRIDAY OVERALL THE MODELS ARE IN DECENT AGREEMENT ON HOW THE UPPER LEVEL PATTERN WILL EVOLVE DURING THE FIRST HALF OF THE LONG TERM PERIOD. BROAD UPPER TROUGHING WILL BE NOTED OVER THE EASTERN CONUS THROUGH THE PERIOD...WITH THE REMNANTS OF A CLOSED UPPER LOW OVER CALIFORNIA BEING ABSORBED INTO THE MEAN EASTERN TROUGH BY WED MORNING. BEYOND THAT HOWEVER THE MODELS DIVERGE GREATLY...AND EVEN WITH THE TUE NIGHT EARLY WED MORNING TIME FRAME THERE ARE SIGNIFICANT DIFFERENCES IN THE HANDLING OF SHORTWAVE ENERGY AND THE ASSOCIATE PRECIP SHIELD. THE GFS SHOWS LIGHT PRECIPITATION ACROSS MUCH OF THE FORECAST AREA TUESDAY NIGHT AND EARLY WED MORNING WHICH...GIVEN THE TEMPERATURES IN PLACE...WOULD BE OF THE WINTRY VARIETY. HOWEVER THE EUROPEAN IS ALMOST COMPLETELY DRY. HAVE GONE SOMEWHAT HEAVY HANDED TOWARDS THE EURO BUT WILL KEEP SOME SLIGHT CHANCE POPS IN THE SOUTHERN COUNTIES TUE NIGHT AND WED TO ACCOUNT SOMEWHAT FOR WETTER GFS SOLUTION. WED NIGHT ONWARD THOUGH...CONFIDENCE DROPS SIGNIFICANTLY. THE EURO DEVELOPS A BROAD TROUGH ACROSS MUCH OF THE LOWER 48...WHILE THE GFS IS NOTICEABLY DIFFERENT. THUS TIMING FOR ANY PARTICULAR DISTURBANCE AND ASSOC PRECIPITATION IS DIFFICULT AT BEST. PREFER TO CARRY NO MENTION OF PRECIP CHANCES DURING THAT PERIOD UNTIL SOMEWHAT OF A CONSENSUS EMERGES. ONE THING DOES SEEM WELL AGREED UPON AND THAT IS THAT TEMPERATURES WILL REMAIN BELOW NORMAL...REGARDLESS OF WHICH MODEL YOU BELIEVE. ANOTHER ARCTIC HIGH WILL SLIP SOUTH FROM CANADA TUE INTO WED...WITH THE LEADING EDGE OF THE COLD AIR REACHING ARKANSAS BY THURSDAY. AFTER HIGHS IN THE 40S TUE AND WED...AFTERNOON READINGS ON THURSDAY WILL STRUGGLE TO BREAK THE FREEZING MARK IN THE NORTH AND NORTHEAST...AND ONLY JUST MAKE 40 IN THE SOUTH. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 30 44 29 34 / 100 100 20 20 CAMDEN AR 45 65 37 43 / 80 90 40 30 HARRISON AR 31 43 25 28 / 100 90 10 20 HOT SPRINGS AR 33 55 34 40 / 90 90 20 20 LITTLE ROCK AR 34 54 33 38 / 90 100 30 20 MONTICELLO AR 39 65 36 41 / 90 90 50 20 MOUNT IDA AR 34 53 34 40 / 90 90 20 20 MOUNTAIN HOME AR 28 44 25 30 / 100 90 20 20 NEWPORT AR 30 45 29 34 / 100 100 30 20 PINE BLUFF AR 36 61 34 39 / 90 100 40 20 RUSSELLVILLE AR 33 51 32 38 / 100 90 20 20 SEARCY AR 31 46 31 36 / 100 100 30 20 STUTTGART AR 34 55 33 37 / 90 100 40 20 && .LZK WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 AM CST SATURDAY FOR BAXTER-CLEBURNE- FULTON-INDEPENDENCE-IZARD-JACKSON-SHARP-STONE. WINTER WEATHER ADVISORY UNTIL 6 AM CST SATURDAY FOR BOONE-CONWAY- FAULKNER-JOHNSON-MARION-NEWTON-POPE-SEARCY-VAN BUREN-WHITE- WOODRUFF. && $$ AVIATION...56
AREA FORECAST DISCUSSION
NWS PUEBLO CO
803 PM MST SUN FEB 22 2015 .UPDATE... ISSUED AT 800 PM MST SUN FEB 22 2015 STEADY ACCUMULATING SNOW IS NOT LIKELY ACROSS THE FAR E PLAINS AND PER COORD WITH SURROUNDING WFO/S...I REMOVED THE HILITES FOR THAT REGION. /HODANISH && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 251 PM MST SUN FEB 22 2015 ...HEAVY SNOW OVER THE MOUNTAINS CONTINUES... ...SNOW WINDING DOWN TONIGHT FOR THE LOWER ELEVATIONS... IN GENERAL...FORECAST IS WORKING OUT FAIRLY WELL ACROSS THE CWA. FORECAST AMOUNTS FOR THE NORTHERN AND EASTERN ZONES WERE TOO HIGH...AND TOO LOW FOR THE MTS AND SRN ZONES...BUT OVERALL AMOUNTS ARE NOT TOO SURPRISING. AS THE UPPER TROUGH SHEARS OFF TO THE WEST OVER CA...AND MID LEVEL WINDS CONTINUE TO VEER TO THE SW AND W...WILL SEE SNOWFALL GRADUALLY DIMINISH OVER THE ERN PLAINS E OF I- 25 TONIGHT...SO HAVE REDUCED POPS THROUGH TONIGHT IN THAT AREA. WILL LEAVE A SNOW ADVISORY GOING WITH ADDITIONAL LIGHT ACCUMS OF AN INCH OR TWO POSSIBLE...AND CONTINUED ICY ROAD CONDITIONS. HIGH RES MODELS ARE SHOWING THE HEAVIER SNOW GRADUALLY BEING TIED TO THE ERN MTS AND HIGHER TRRN...AND THIS LOOKS REASONABLE. THERE COULD BE SOME BANDED PRECIP SPILLING OVER TO PORTIONS OF THE I-25 CORRIDOR...ESPECIALLY W OF I-25...THROUGH THIS EVENING...SO WILL LEAVE THE WARNING INTACT FOR THE I-25 ZONES. IN FACT...THE HRRR CONTINUES TO SHOW SN PICKING UP FOR A BIT EARLY THIS EVENING OVER EL PASO COUNTY BEFORE DIMINISHING AFTER MIDNIGHT. LATER SHIFT CAN REEVALUATE AND DOWNGRADE THE WARNING IF IT LOOKS LIKE THIS WILL NOT MATERIALIZE. OVER THE MTS...SNOW CONTINUES THROUGH TOMORROW. WIND SENSOR IS OUT AT KCPW...BUT AS MENTIONED IN THE EARLIER UPDATE BLIZZARD CONDITIONS WERE OCCURRING THERE AND WILL LIKELY CONTINUE THROUGH PERIODS OF MONDAY BEFORE THINGS BEGIN TO QUIET DOWN. LATEST GUIDANCE SUGGESTS AN ADDITIONAL 2-3 FEET OVER THE SAN JUANS BY TUESDAY...SO WOULD NOT BE SURPRISED TO SEE A FEW SPOTS NEAR 4 FEET BY THE TIME THIS ENDS...AND WITH HIGH WINDS SOME SERIOUS DRIFTING AS WELL...INCREASING AN UNSTABLE SNOW LOAD ON THE SLOPES AND RESULTING IN EXTREME AVALANCHE THREAT OVER THE HIGH COUNTRY FOR THE NEXT FEW DAYS. INTERESTINGLY...LATEST GUIDANCE IS SHOWING H7 TEMPS OF MINUS 21 DEGREES OVER OUR AREA TONIGHT...SIGNIFICANTLY COLDER THAN WHAT THE MODELS WERE SHOWING JUST A COUPLE OF DAYS AGO...AND IN LINE WITH THE ECMWF GUIDANCE FROM A WEEK AGO! THE MUCH COLDER AIR HAS CUT BACK A BIT ON DENDRITIC SNOW GROWTH...AND LIMITED SNOW AMOUNTS TO SOME EXTENT FOR OUR ERN ZONES. AS A RESULT OF THE COLDER AIR ALOFT...EXPECT SOME LOWS CLOSE TO ZERO TONIGHT EVEN WITH THE CLOUD COVER...AND HAVE REDUCED HIGHS A BIT FOR TOMORROW WITH TEMPS PROBABLY STAYING IN THE TEENS FOR THE MOST PART. EXPECT GRADUAL IMPROVEMENT TOMORROW FOR THE PLAINS...AS WRLY FLOW INCREASES. MODELS ARE SHOWING A LACK OF QPF THERE TOMORROW...BUT WITH ABUNDANT LOW LEVEL MOISTURE AND CONTINUED SHALLOW UPSLOPE...AM RELUCTANT TO REMOVE POPS COMPLETELY...SO WILL LEAVE LOW POPS IN PLACE OVER THE PLAINS. OVER THE MTS...HEAVY SNOW CONTINUES AT TIMES WITH BLIZZARD CONDITIONS FOR THE ERN SAN JUANS. SAN LUIS VALLEY WILL BE BETWEEN THE TWO REGIMES AND COULD SEE SOME SHSN...BUT NOTHING PARTICULARLY HEAVY EXPECTED. WELCOME BACK TO WINTER! ROSE .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 251 PM MST SUN FEB 22 2015 MONDAY NIGHT THE UPR LOW IS FORECAST TO MOVE EASTWARD FROM SRN NV...WITH THE GFS SHOWING THE LOW CENTER OVR NERN AZ BY 12Z TUE AND THE NAM BEING A LITTLE FARTHER WEST. EITHER WAY...SNOW CONTINUES OVR THE SWRN CO MTNS. HOWEVER WITH THE GFS BEING FARTHER EAST THAN THE NAM...PCPN IS ALSO FORECAST TO BE OVR THE SAN LUIS VALLEY AND THE ERN MTNS...WHILE THE NAM HAS DRY CONDITIONS EVERY BUT THE SW MTNS. ON TUE THE UPR LOW IS EXPECTED TO CONTINUE AN EASTWARD TRACK...MOVING ACRS NRN NM...BRINGING MAINLY SOME PCPN CHANCES TO MAINLY THE FAR SOUTHERN PORTIONS OF THE FORECAST AREA. HIGH TEMPS ON TUE WL BE A LITTLE WARMER...BUT STILL BELOW AVERAGE...ESPECIALLY WITH THE SNOW COVER. TUE NIGHT AND EARLY WED DRY CONDITIONS ARE EXPECTED OVR THE AREA AS THE UPR LOW MOVES INTO NORTHERN TX. A NEW UPR TROF DROPS INTO THE STATE FROM THE SOUTH BY LATE WED MORNING...PUSHING MORE COLD AIR INTO THE AREA. IN THE LATE MORNING OR EARLY AFTERNOON HOURS...PCPN IS EXPECTED TO SPREAD SOUTH ACRS THE AREA AS WELL...WITH PROBABLY THE HARDEST HIT AREAS BEING THE EASTERN MTS AND IMMEDIATELY ADJACENT PLAINS AND THE PALMER DIVIDE. THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT...KEEPING PCPN ACRS MUCH OF THE SERN PLAINS AND MTNS THRU THU NIGHT AND MUCH OF FRI AS ANOTHER UPR DISTURBANCE MOVES INTO THE AREA FROM THE PACIFIC NW. THIS WL BRING THE POTENTIAL FOR SEVERAL INCHES OF SNOW OVR THE MTNS. UPSLOPE FLOW OVR ERN AREAS WL HELP TO BRING SEVERAL INCHES TO THE THE WET MTNS...SOUTHERN SANGRES AND THE ADJACENT PLAINS...WITH MAYBE A COUPLE TO A FEW INCHES ALONG THE I-25 CORRIDOR...AND LIGHTER ACCUMULATIONS OVR THE FAR SERN PLAINS. UNSETTLE WEATHER IS FORECAST TO CONTINUE NEXT WEEKEND AS ANOTHER UPR TROF AFFECTS THE STATE...KEEPING THE WEATHER COOL AND BRINGING PCPN CHANCES TO MUCH OF THE AREA AND THE POTENTIAL FOR SEVERAL INCHES OF SNOW IN THE MTNS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 251 PM MST SUN FEB 22 2015 SN WILL GRADUALLY WIND DOWN THIS EVE FOR KPUB AND KCOS...AS ACCUMULATING SNOW BECOMES TIED TO THE HIGHER TRRN ALONG THE RAMPARTS...WETS...AND SANGRES. WILL STILL SEE SOME AREAS OF LIGHT TO MDT SN MOVE OUT OVER THE I-25 CORRIDOR THIS EVE...SO THERE WILL BE THE CONTINUED THREAT OF IFR CONDITIONS. PERSISTENT SE FLOW SHOULD KEEP KCOS IN IFR TO LIFR CONDITIONS THROUGH MON MORNING...WITH AREAS OF FZFG POSSIBLE IN THE MORNING DUE TO THE SNOW PACK AND VERY COLD CONDITIONS. AT KALS...MVFR TO IFR ALSO POSSIBLE IN PERIODS OF LIGHT SN THROUGH AT LEAST THE FIRST PART OF MONDAY. NOT MUCH OF A BREAK BETWEEN STORMS AS ANOTHER WINTER SYSTEM LOOKS TO IMPACT OUR AREA LATE WED INTO THU. ROSE && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ058>063- 072>088. WINTER WEATHER ADVISORY UNTIL 5 PM MST MONDAY FOR COZ069>071. WINTER STORM WARNING UNTIL 5 PM MST MONDAY FOR COZ064>067. BLIZZARD WARNING UNTIL 11 PM MST MONDAY FOR COZ068. && $$ UPDATE...HODANISH SHORT TERM...28/ROSE LONG TERM...28 AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
426 PM EST SAT FEB 21 2015 .SYNOPSIS... A LOW PRESSURE SYSTEM TRACKS DOWN THE SAINT LAWRENCE RIVER VALLEY TONIGHT THROUGH SUNDAY NIGHT...WITH ITS COLD FRONT CROSSING THE AREA THROUGH SUNDAY AFTERNOON. AN ARCTIC FRONT PASSES THROUGH SUNDAY NIGHT WITH ARCTIC HIGH PRESSURE BUILDS IN ITS WAKE THROUGH MONDAY NIGHT BEFORE SLIDING OFF THE MID ATLANTIC COAST ON TUESDAY. A COLD FRONT WILL THEN APPROACH THE AREA TUESDAY NIGHT AND PASS THROUGH WEDNESDAY AFTERNOON OR NIGHT...FOLLOWED BY HIGH PRESSURE FOR THE REST OF THE WEEK. && .NEAR TERM /THROUGH SUNDAY/... PRIMARY LOW CONTINUES TO TRACK NW THROUGH THE EASTERN GREAT LAKES AND ST LAWRENCE RIVER VALLEY THIS EVENING INTO TONIGHT...WITH A WARM FRONT APPROACHING THE REGION LATER TONIGHT...WITH POTENTIAL WEAK WAVE DEVELOPMENT ALONG IT. ITS TRAILING COLD FRONT PASSES THROUGH SUNDAY AFTERNOON. MODERATE TO HEAVY SNOW OVER NYC/NJ METRO...RAPIDLY SPREADING INTO LI AND SOUTHERN CT THIS EVENING...WITH A STEADY PLUME OF MOISTURE COMING UP ALL THE WAY DOWN INTO THE MID ATLANTIC. PERIODS OF MODERATE TO HEAVY SNOW EXPECTED ACROSS THE COASTAL PLAIN INTO THIS EVENING...WITH SNOWFALL RATES UP TO 1 INCH PER HOUR. LIGHT TO MODERATE SNOW FOR AREAS FAR NW OF NYC METRO. HIGH RES MODELS AND HRRR HAVE CONTINUED THE TREND OF SHIFTING HEAVIEST QPF AXIS A BIT FARTHER SE...ACROSS THE COASTAL PLAIN...WITH THIS SYSTEM. STILL EXPECTING 3/4 TO 1 INCH QPF ACROSS THE COASTAL PLAIN...BUT COULD BE AS LOW AS 1/4 TO 1/2 INCH ACROSS AREAS WELL NW OF NYC. MODELS HAVE ALSO TRENDED COLDER SINCE THE 00Z RUNS. WINTER WEATHER ADVISORIES CONTINUE FOR THE ENTIRE AREA. BASED ON UPSTREAM RADAR AND HIGH-RES DATA...AND ABOVE THINKING...HAVE ADJUSTED SNOWFALL AMOUNTS UPWARD FOR THE NYC/NJ METRO AND COAST AND STATUS-QUO FOR INTERIOR. A NARROW BAND OF 5 TO 7 INCHES OF SNOW...MARGINAL WARNING...IS NOT OUT OF THE QUESTION ACROSS THE COASTAL PLAIN (INCLUDING NYC AND LI)...BUT LOW CONFIDENCE AT THIS POINT THAT IT WILL BE WIDESPREAD ENOUGH TO UPGRADE TO WARNING AND WITH LOOMING CHANGEOVER. IN FACT...THE RAP AND HRRR...ARE SHOWING POTENTIAL FOR A 1/2 INCH OF QPF AS ALL SNOW ACROSS NYC AND LI BEFORE CHANGEOVER. AS FOR SNOWFALL AMOUNTS...A GENERAL 3 TO 6 INCH SNOWFALL ACROSS THE NYC METRO...LI AND SE CT BEFORE CHANGEOVER THIS EVENING...WITH LOCALLY 6+ INCHES. ACROSS NE NJ...LOWER HUDSON VALLEY AND SW CT A GENERAL 4 TO 7 INCHES IS STILL LIKELY...BUT IF DRYING TREND CONTINUES...AREAS FARTHER NW OF NYC...COULD END UP ON THE LOWER END OF THE RANGE. THE FORECAST CHALLENGES TONIGHT CONTINUE TO BE HOW FAST DOES A LOW LEVEL WARM NOSE FROM AROUND 875-975 HPA MOVE IN AND DEGREE OF SHALLOW COLD AIR GETTING LOCKED IN AT THE SURFACE AS COASTAL FRONT/WARM FRONT APPROACH TONIGHT. BEST ESTIMATE IS FROM S TO N FROM 02Z TO 06Z WITH ENSUING CHANGEOVER TO LIQUID. AT THE SURFACE...12Z NAM AND SBU/ALY WRF INDICATING A WEAK MESO- LOW DEVELOPING ALONG THE WARM FRONT OVER OR JUST SOUTH OF LI...WHICH WOULD KEEP THE WARM FRONT SOUTH OF AND PROMOTE TRAPPING OF SUB- FREEZING SURFACE AIR DOWN INTO AT LEAST NORTHERN PORTIONS OF LI AND NYC METRO AND POINTS N AND W TONIGHT. BASED ON THIS TREND...HAVE FORECAST MORE FREEZING RAIN/ICE ACCUM AND FURTHER SOUTH INTO THE COASTAL PLAIN. EXPECTATION IS A BAND OF A TENTH...POSSIBLY 2 TENTHS...OF AN INCH OF ICE IN A CORRIDOR RUNNING FROM NE NJ...NORTHERN PORTIONS OF NYC METRO/LI INTO SW CT. PRECIP WILL BECOMING LIGHT LATE TONIGHT...BUT COULD HAVE TEMPS LINGERING NEAR FREEZING TILL AROUND DAYBREAK HERE...FOR AT LEAST LIGHT FREEZING RAIN. SO HAVE EXTENDED ADVISORY HERE UNTIL 8 AM. ELSEWHERE...ONLY BRIEF MIXING EXPECTED AFTER MIDNIGHT ACROSS FAR INTERIOR PORTIONS OF THE LOWER HUDSON VALLEY AND SW CT WITH UP TO A FEW HUNDREDTHS OF AN INCH ICE. ALONG THE SOUTHERN PORTIONS OF NYC/LI AND SE CT...SURFACE TEMPS SHOULD BE ABLE TO WARM ENOUGH LATE THIS EVENING AND AFTER MIDNIGHT FOR A TRANSITION TO MAINLY RAIN. KEEP IN MIND THOUGH...WITH COLD PREDECESSOR TEMPS...ROAD ICING MAY BE POSSIBLE ALL THE WAY TO THE COAST FOR AT LEAST A COUPLE OF HOURS AFTER CHANGEOVER TO RAIN FOR AT LEAST. PRECIP BECOMES LIGHTER LATE TONIGHT...TAPERING OFF FROM W TO E EARLY SUNDAY MORNING. OTHERWISE...DRYING CONDS ON SUNDAY WITH PARTIAL CLEARING. TEMPERATURES WILL REMAIN STEADY INTO EARLY THIS EVENING ACROSS THE INTERIOR...AND SLOWLY FALLING ALONG THE COAST. TEMPS THEN GRADUALLY RISING LATE THIS EVENING INTO OVERNIGHT...CONTINUING TO RISE INTO THE MID TO UPPER 30S. && .SHORT TERM /SUNDAY NIGHT/... SHORTWAVE AXIS CROSSES SUNDAY NIGHT...WITH LOW PRESSURE LIFTING INTO SE CANADA...AND ARCTIC FRONT PRESSING THROUGH THE REGION. DRYING LOW LEVEL NW FLOW WILL HAVE TEMPS DROPPING INTO THE TEENS CITY/COAST AND SINGLE DIGITS INTERIOR. WINDCHILLS DROPPING TO 0 TO 5 ALONG THE COAST BY MONDAY MORNING...AND 0 TO 5 BELOW ACROSS THE INTERIOR. && .LONG TERM /MONDAY THROUGH SATURDAY/... HIGH PRESSURE BUILDS IN MONDAY AND MONDAY NIGHT WITH COLD ADVECTION THROUGH AT LEAST MONDAY MORNING. TEMPERATURES PROBABLY STILL FALL THROUGH THE MORNING HOURS BEFORE PERHAPS RECOVERING A DEGREE OR TWO. HIGHS FOR THE DAY PROBABLY OCCUR DURING THE PRE-DAWN HOURS...AND WITH 900MB TEMPS FALLING TO AROUND -20C...EXPECT DAYTIME TEMPS IN THE TEENS. FOR MONDAY NIGHT...WENT BELOW GUIDANCE BY A COUPLE OF DEGREES OUTSIDE OF THE CITY. LOWS IN THE SINGLE DIGITS FOR THE CITY...AND MOSTLY 5 BELOW TO 5 ABOVE ELSEWHERE. RECORD LOWS FOR MOST OF OUR OFFICIAL CLIMATE SITES SHOULD BE BROKEN. WIND CHILLS EXPECTED IN THE SINGLE DIGITS BELOW ZERO...DUE PRIMARILY TO THE ACTUAL TEMPERATURE AND NOT SO MUCH THE WIND. DRY FOR TUESDAY...THEN WARM ADVECTION COULD CAUSE SOME LIGHT SNOW TUESDAY NIGHT INTO WEDNESDAY MORNING WITH BETTER OVERALL CHANCES OVER THE NORTHERN ZONES. A COLD FRONT THEN MOVES THROUGH WEDS AFTERNOON INTO NIGHT. MOISTURE BY THIS TIME ISN`T MUCH...SO JUST A SLIGHT CHANCE OF A SNOW SHOWER. AFTER HIGHS IN THE 20S ON TUESDAY...HIGHS MOSTLY 30-35 ON WEDNESDAY. CAA FOLLOWS BEHIND THE FRONT...LEAVING US WITH HIGHS ONLY IN THE 20S ONCE AGAIN ON THURSDAY...BUT AT LEAST WITH DRY WEATHER. HIGH PRESSURE WILL BE BUILDING IN THROUGH FRIDAY...SO CONTINUED DRY...BUT WITH HIGHS ONLY IN THE 20S AGAIN. FOR SATURDAY...HIGH PRESSURE SHIFTS OFFSHORE WITH MODELS SHOWING LOW PRESSURE MOVING IN FROM THE SW. WILL GO WITH SLIGHT CHC/CHC POPS FOCUSED MORE IN THE AFTERNOON AND NIGHT. PCPN TYPE WOULD START AS SNOW...BUT MIXED PCPN COULD COULD OCCUR AT NIGHT. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... LOW PRES MOVING INTO THE TN VALLEY WILL LIFT NORTH INTO THE REGION TONIGHT AND WILL PASS OVER THE TERMINALS LATE TONIGHT AND THROUGH SUNDAY MORNING. SNOW CONTINUES TO SPREAD EAST ACROSS THE TERMINALS THROUGH THIS EVENING. IFR/LIFR CONDS IN MODERATE TO LOCALLY HEAVY SNOW THROUGH ABOUT 02Z. KSWF SHOULD STAY ALL SNOW FOR THE DURATION OF THE EVENT...BUT THERE WILL BE A TRANSITION TO FZRA STARTING ALONG THE COAST AND LIFTING NORTHWARD DURING THE EVENING HOURS. FZRA AT KJFK/KISP/KGON SHOULD ONLY LAST FOR A BRIEF PERIOD BEFORE PRECIP CHANGES TO PLAIN RAIN AFTER MIDNIGHT...AND THEN TAPERS OFF... POSSIBLY AS A RAIN/SNOW MIX...SUNDAY MORNING. KLGA/KEWR/KTEB/KHPN/KBDR CAN EXPECT A PROLONGED PERIOD OF FZRASN THROUGH THE OVERNIGHT HOURS...TAPERING OFF AS A WINTRY MIX SUNDAY MORNING. SOUTH WINDS MAY GUST TO AROUND 20 KT FROM TIME TO TIME THROUGH THIS EVENING...BUT WINDS THEN DIMINISH LATER THIS EVENING. SOUTH WINDS BECOME SW AT LESS THAN 10 KT TONIGHT...AND THEN BECOME LGT/VRB LATE TONIGHT AS THE LOW PASSES OVER THE REGION. WINDS THEN BECOME WNW SUNDAY MORNING AT LESS THAN 10 KT. STRONG LLJ WILL ALSO PASS THROUGH THE REGION...RESULTING IN SW WINDS 40-50 KT AT 2000 FT DURING THE LATE AFTERNOON/EVENING HOURS. RUNWAY SNOW ACCUM FCST: KJFK/KISP/KGON: 1-3 KLGA/KEWR/KTEB/KBDR: 2-4 KHPN: 3-5 KSWF: 4-6 RUNWAY ICE ACCUM FCST: KJFK/KISP/KGON: TRACE KLGA/KEWR/KTEB/KHPN/KBDR: 0.10-0.20 INCH. .OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY... .SUNDAY AFTERNOON...IMPROVING CONDS. NW WINDS 10 KT OR LESS. .SUNDAY NIGHT...MVFR POSSIBLE EARLY...THEN VFR. NW WINDS 10-15 KT. .MONDAY...VFR. NW WINDS 15-20 KT WITH 20-30 KT GUSTS. .MONDAY NIGHT-WEDNESDAY. SUB-VFR OR LOWER POSSIBLE IN SN. COASTAL STORM POSSIBLE. CONFIDENCE LOW ON TIMING. .THURSDAY...VFR LIKELY. && .MARINE... SCA WINDS CONTINUE ON THE OCEAN THROUGH AROUND 06Z BEFORE SUBSIDING...WITH SEAS BUILDING TO 6 TO 10 FT. MARGINAL SCA GUSTS ACROSS SOUTHERN AND EASTERN BAYS THROUGH THIS TIME AS WELL. SUB SCA WINDS EXPECTED LATE TONIGHT THROUGH SUN...BUT SOUTHERLY SCA SWELLS CONTINUE ON THE OCEAN. SUNDAY NIGHT AND MON...SMALL CRAFT ADVISORY LEVELS POSSIBLE ALL WATERS BY DAYBREAK IN WAKE OF ARCTIC FRONT...WITH CONTINUATION OF 5+ FT SEAS ON THE OCEAN. WINDS AND SEAS WILL GRADUALLY DIMINISH MONDAY AND MONDAY NIGHT...WITH ALL WATERS DROPPING BELOW SCA CONDS MONDAY NIGHT. HIGH PRESSURE BUILDS TO THE SOUTH...SHIFTING WINDS FROM WNW TO SW ON TUESDAY...GENERALLY BELOW 15 KT. WINDS INCREASE A LITTLE TUESDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS DUE TO LOW PRESSURE MOVING JUST NORTH OF THE GREAT LAKES. THIS WILL DRAG A COLD FRONT THROUGH THE WATERS SOMETIME LATE WEDNESDAY OR WEDNESDAY NIGHT. SCA CONDS ARE THEREFORE PROBABLE ON THE OCEAN WATERS TUES NIGHT THROUGH WEDS NIGHT...AND MARGINALLY AT ADVISORY CONDS ON ALL OTHER WATERS DURING THIS PERIOD. HIGH PRESSURE BUILDS BACK IN ON THURSDAY...BUT GUSTS WILL BE CLOSE TO 25 KT ON THE OCEAN WATERS. NOTE THAT WITH EXTREMELY LOW AIR TEMPERATURES...ICE WILL CONTINUE TO DEVELOP ACROSS THE REGION AND CAN DISRUPT MARITIME TRAVEL. && .HYDROLOGY... EXPECTING A LIQUID EQUIVALENT OF 1/4 TO 1/2 INCH FAR NW OF NYC...WITH 1/2 TO 1 INCH FOR THE REMAINDER OF THE REGION. HEAVIEST ACROSS EASTERN LI AND SE CT. THERE IS THE POTENTIAL FOR PONDING OF OVER EASTERN LONG ISLAND AND COASTAL NEW LONDON COUNTY...ESPECIALLY IN AREAS WITH DRAINS CLOGGED BY SNOW TONIGHT. NO SIGNIFICANT PCPN AMOUNTS EXPECTED THROUGH AT LEAST FRIDAY. ICE WILL CONTINUE TO DEVELOP ON LOCAL AREA RIVERS AND STREAMS AS TEMPS CONTINUE TO AVERAGE WELL BELOW NORMAL. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR CTZ008-011- 012. WINTER WEATHER ADVISORY UNTIL 8 AM EST SUNDAY FOR CTZ005>007- 009-010. NY...WINTER WEATHER ADVISORY UNTIL 1 AM EST SUNDAY FOR NYZ075- 079>081-178-179. WINTER WEATHER ADVISORY UNTIL 8 AM EST SUNDAY FOR NYZ067>074- 078-176-177. NJ...WINTER WEATHER ADVISORY UNTIL 8 AM EST SUNDAY FOR NJZ002-004- 006-103>108. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST MONDAY FOR ANZ350-353-355. && $$ SYNOPSIS...JC/NV NEAR TERM...NV SHORT TERM...NV LONG TERM...JC AVIATION...MPS MARINE...JC/NV HYDROLOGY...JC/NV
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
854 PM EST SUN FEB 22 2015 ...GRADUAL INCREASE IN RAIN CHANCES THROUGH MONDAY... ...AREAS OF FOG FOR TONIGHT/EARLY MONDAY MORNING... .UPDATE...NEARLY STATIONARY FRONT ACROSS NRN CENTRAL GA TO SERN AL TO SRN LA THIS EVENING WILL GET A NUDGE E AND SE AS MEAN LAYER TROUGH OVER THE ERN U.S. MOVES DOWNSTREAM. RADAR TRENDS SHOW SHOWER ACTIVITY OVER SE AL AND CENTRAL GA LIGHT TO MODERATE AT TIMES WITH SOME EVIDENCE OF SHIFTING ESEWD. MOISTURE ACROSS OUR AREA HAS RISEN SINCE YESTERDAY WITH DEWPOINTS IN THE UPPER 50S TO AROUND 60. EXPECT RAIN CHANCES TO INCREASE AS THE FRONT EDGES INTO OUR GA ZONES TO NEAR THE ALTAMAHA RIVER BY 12Z MON. WILL USE SCT POPS IN THE 30-40 PERCENT RANGE FOR LOCATIONS N OF A JESUP TO DOUGLAS LINE WITH REST OF SE GA AROUND 10-20 PERCENT AS BEST LIFT WILL BE LOCATED N OF THE AREA. MAY INCREASE POPS A BIT MORE FOR LOCATIONS N OF ALMA BASED ON RADAR TRENDS AND HRRR GUIDANCE. TEMPS ONLY TO FALL TO THE MID TO UPPER 50S TONIGHT. OTHER ISSUE IS THE PROSPECTS FOR FOG. WITH CLOUDS INCREASING OVER SE GA PATCHY FOG STILL LOOKS GOOD THERE WITH AREAS OF FOG WITH LOW CLOUDS FOR NE FL...DUE TO COMBINATION OF RADIATION FOG AND ADVECTIVE FOG/LOW CLOUDS EMANATING FROM THE NE GULF OF MEXICO. SOME DENSE FOG IS CERTAINLY POSSIBLE OVER NE FL AND POSSIBLY EXTREME SE GA ZONES. MONDAY...COLD FRONT WILL MOVE THROUGH SE GA IN THE MORNING AND NE FL DURING THE AFTN. THE FRONT WILL BRING A GENERAL INCREASE IN RAIN CHANCES...MAINLY IN SE GA. COOLER HIGH TEMPS EXPECTED...BUT STILL IN THE MID 60S N ZONES TO MID 70S S PORTIONS. && .AVIATION...MOISTURE WILL CONTINUE TO INCREASE TONIGHT AS A COLD FRONT CONTINUES TO EDGE CLOSER TO THE AREA. THIS WILL LEAD TO AREAS OF LATE NIGHT AND MORNING LOW CLOUDS AND FOG. HAVE PREVAILING MVFR AT GNV AND VQQ BEGINNING AT 09Z WITH OCNL IFR BETEEN 09Z-13Z. FOR THE REST OF THE TERMINALS HAVE OCNL MVFR BETEEN 10Z-14Z. PREVAILING MVFR IS EXPECTED AT ALL TERMINALS BETWEEN 14Z-20Z BEFORE CIGS IMPROVE INTO THE VFR CATEGORY. THE COLD FRONT WILL PUSH SE INTO THE AREA MONDAY AFTERNOON. BEST CHANCE OF RAIN ACROSS SE GA WHERE SSI WILL HAVE VCSH. && .MARINE...CURRENT FORECAST ON TRACK. S TO SW WINDS AROUND 10-15 KT AND SEAS 2 TO 4 FEET...AROUND 3 TO 5 FEET OFFSHORE. WIND AND SEA CONDITIONS DETERIORATE ON MONDAY AS THE COLD FRONT MOVES INTO THE FORECAST REGION. WITH ELEVATED DEWPOINTS IN THE MID TO UPPER 50S SOME PATCHY SEA FOG IS POSSIBLE OVER SE GA NEARSHORE WATERS MONDAY MORNING. RIP CURRENTS: LOW RISK THROUGH MONDAY DUE TO LOW SEAS AND SURF. && .PRELIMINARY POINT TEMPS/POPS... AMG 56 65 42 52 / 30 30 40 40 SSI 56 63 46 50 / 20 40 40 50 JAX 57 71 48 53 / 10 40 50 50 SGJ 57 70 53 55 / 10 30 40 50 GNV 57 75 51 60 / 10 30 30 40 OCF 58 76 54 65 / 10 20 20 40 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...SMALL CRAFT ADVISORY FROM 6 PM MONDAY TO MIDNIGHT EST TUESDAY NIGHT FOR WATERS FROM ALTAMAHA SOUND GA TO FERNANDINA BEACH FL FROM 20 TO 60 NM-WATERS FROM FERNANDINA BEACH TO ST. AUGUSTINE FL FROM 20 TO 60 NM-WATERS FROM ST. AUGUSTINE TO FLAGLER BEACH FL FROM 20 TO 60 NM. SMALL CRAFT ADVISORY FROM 6 PM MONDAY TO 10 AM EST TUESDAY FOR COASTAL WATERS FROM ALTAMAHA SOUND TO FERNANDINA BEACH FL OUT 20 NM-COASTAL WATERS FROM FERNANDINA BEACH TO ST. AUGUSTINE FL OUT 20 NM-COASTAL WATERS FROM ST. AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM. && $$ SHASHY/PETERSON/WALKER Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 900 PM CST Sun Feb 22 2015 .UPDATE... ISSUED AT 857 PM CST SUN FEB 22 2015 Strong Arctic high pressure will continue to build into the area overnight on schedule. Surface temperatures are still above zero, but wind speeds have been sufficient to drop Wind Chill values below zero across most of the forecast area. While wind speeds will die off some overnight as the high approaches and pressure gradient relaxes, sub-zero air temperatures will allow Wind Chill values to fall to advisory levels. Going forecast is in good shape. Only a few tweaks for the latest hourly trends are required. && .SHORT TERM...(Tonight) ISSUED AT 240 PM CST SUN FEB 22 2015 Another Arctic air mass settling into our area for tonight and Monday bringing bitterly cold wind chills tonight through the mid-morning hours of Monday with values in the -15 to -25 degree range. Latest upstream observations mostly in the single digits across north central through northeast Iowa with wind gusts up to 30 mph at times. Early morning lows are expected to dip to -2 in the far south to as low as -8 across the north just before dawn Monday. The center of the Arctic high is forecast by models to drift into southeast Iowa by 12z Monday with the surface ridge axis extending northeast into northern Illinois. Forecast soundings and the latest HRRR model suggests the cloud cover we have over the area this afternoon will drift east and south later this evening with mainly some cirrus for the first half of the night and then a mostly clear sky is expected after midnight most areas. Current Wind Chill Advisory will remain in place for late tonight through 9AM Monday morning. && .LONG TERM...(Monday through Sunday) ISSUED AT 240 PM CST SUN FEB 22 2015 As the center of the cold air mass drifts across the area tomorrow, look for winds to diminish during the day but temperatures will be slow to rise with afternoon highs struggling to 10 to 15. The high should be moving off to our east by afternoon and early evening with our next surface low and cold front tracking across southern Canada southwest through the Northern Plains. Early in the evening, surface winds will be light enough for our usual tank with early evening temperatures before we see a steady or slowly rising trend across the north and west, while further east with a lighter wind flow, early morning lows will dip several degrees below zero Monday night into Tuesday morning. As the deep surface low tracks north of Lake Superior on Tuesday, a gusty south to southwest wind should help the mercury climb into the mid 20s far east to the low to mid 30s far west where we should be able to mix out fairly well during the afternoon. With the better upper forcing remaining well to our north and very limited moisture, models not showing much if any precip associated with the boundary as it swings across our area late in the day, except for the GFS which continues to produce a large area of 0.01 qpf with this system. Not worth much more than a chance for flurries and will continue with that for later in the day on Tuesday. Then we will see another cold air mass build gradually southeast thru midweek. The GFS and latest ECMWF continue to show a weak shortwave racing southeast into the Plains on Wednesday along the periphery of the next batch of cold air for the remainder of the work week. The GFS keeps any precip associated with this wave to our west and south while the latest ECMWF has trended in that direction as well but does bring in some light QPF late Wednesday/Wednesday evening. Based on the latest westward shift with the ECMWF, will only have slight chances Wednesday night for light snow. Colder temperatures filter into the area again Wednesday night with early morning lows dropping into the single digits with wind chills dropping to near -10 by Thursday morning. And a real surprise here, the well below normal temperatures are expected to hold on across our area through at least the end of the work week with daytime highs in the teens and early morning lows dropping into the single digits with a few below zero readings again possible early Friday morning. Both the GFS and ECMWF indicate a significant change to the upper pattern with more of a southwesterly flow developing over the weekend which will lead to an increasing threat for precipitation. Models showing more agreement from what we saw yesterday with snow chances moving in starting on Saturday night with the threat for snow or rain on Sunday with warming temperatures. Even seeing some better agreement with the ensemble members with respect to the pattern change along with timing of the precip into our area later Saturday through Sunday. Temperatures will start to turn around on Saturday and Sunday, but still average below the normal highs of 40 to 45 across the area for late February. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 531 PM CST SUN FEB 22 2015 VFR aviation weather Condtions are expected to prevail across the central Illinois terminals through the 00Z TAF valid time. Mid/high level CIGS will gradually diminish with time, with mostly clear skies expected by midday Monday. Northerly breezes from 10-15 kts tonight will become light/variable by Monday afternoon as high pressure builds across the area. && .ILX WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY from Midnight tonight to 9 AM CST Monday FOR ILZ027>031-036>038-040>057-061>063-066>068-071>073. && $$ UPDATE...Bak SHORT TERM...Smith LONG TERM...Smith AVIATION...Bak
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
758 PM CST SUN FEB 22 2015 .UPDATE... 757 PM CST MADE A COUPLE TWEAKS TO GOING FORECAST`S TEMPERATURES...MAINLY TO RAISE LOW TEMPS A BIT TONIGHT...ESPECIALLY IN THE URBAN HEAT ISLAND AND ALSO NUDGED HIGHS UP A BIT MONDAY AS WELL. COLD ARCTIC AIR CONTINUES TO SLOWLY FILTER INTO THE AREA...BUT GRADIENT IS REMAINING TIGHT ENOUGH TO KEEP A BIT OF WIND BLOWING WHICH IS PREVENTING TEMPS FROM TANKING DESPITE THE CLEAR SKY. THE TYPICALLY COLDER AND MORE SHELTERED AREAS LIKE FOX AND ROCK RIVER VALLEYS WILL LIKELY SEE WINDS DECOUPLE A BIT MORE THAN OTHER AREAS WITH TEMPS DROPPING TO AROUND 10 BELOW THERE...BUT DOWNTOWN CHICAGO WILL PROBABLY ONLY DROP TO AROUND ZERO. THE MINOR ADJUSTMENTS TO TEMPERATURES AND WINDS SUGGEST THAT MOST AREAS WILL FALL SHORT OF REACHING WIND CHILL ADVISORY CRITERIA...WITH MOST LIKELY AREAS TO REACH IT BEING NORTH CENTRAL ILLINOIS INTO THE FAR WESTERN CHICAGO SUBURBS...WITH WIND CHILLS ELSEWHERE LIKELY "ONLY" DROPPING TO 15-20 BELOW. ITS POSSIBLE THAT MIDNIGHT SHIFT COULD KILL WIND CHILL ADVISORY EARLY...BUT JUST NOT COMFORTABLE MAKING CHANGES TO THE HEADLINE AT THIS TIME. IZZI && .SHORT TERM... 234 PM CST TONIGHT THROUGH WEDNESDAY... COLD TEMPERATURES AND DANGEROUSLY LOW WIND CHILLS TONIGHT AND EARLY MONDAY ARE THE IMMEDIATE FORECAST CONCERNS IN THE SHORT TERM. WIND CHILL ADVISORY REMAINS IN EFFECT FOR ENTIRE CWA FROM MIDNIGHT TONIGHT THROUGH 10 AM CST MONDAY MORNING. COULD EVEN APPROACH ROCKFORDS RECORD LOW OF -12 F. 1047 MB HIGH PRESSURE CENTERED OVER THE NORTHERN PLAINS THIS AFTERNOON WILL CONTINUE TO SPREAD SOUTHEAST TO THE MID-MISSISSIPPI VALLEY TONIGHT. ARCTIC AIR...VERY DRY AIR MASS AND CLEAR SKIES... AND SLOWLY DIMINISHING WINDS WILL COMBINE TO PRODUCE BITTER COLD SUB-ZERO TEMPERATURES ACROSS THE FORECAST AREA OVERNIGHT. WITH LOW TEMPS REACHING FROM -2 TO -14 ACROSS THE CWA AND WINDS JUST UNDER 10 MPH BY MORNING...WIND CHILLS RANGING FROM NEAR 20 BELOW TO NEARLY 30 BELOW ARE EXPECTED BY SUNRISE MONDAY. THUS WIND CHILL ADVISORY REMAINS IN EFFECT FOR ALL COUNTIES WITH NO CHANGES. ON MONDAY...THE SURFACE HIGH AND EASTERN PORTION OF THE RIDGE AXIS WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE AREA IN THE MORNING BEFORE BECOMING ELONGATED ACROSS THE OHIO VALLEY LATE IN THE DAY. COLD MORNING MINS AND SHALLOW MIXING IN THE VICINITY OF THE RIDGE WILL LIKELY KEEP DAYTIME TEMPS IN THE SINGLE DIGITS TO NEAR 10 DEGREES IN MOST AREAS...DESPITE WINDS BECOMING WEST-SOUTHWEST AND STARTING TO INCREASE DURING THE AFTERNOON. THIS WILL LIKELY RESULT IN A RECORD LOW-MAX TEMP FOR THE ROCKFORD AREA MONDAY...AS THE CURRENT RECORD LOW-MAX FOR RFD 2/23 IS A FAIRLY MILD 17 DEGREES. WIND CHILLS WILL REMAIN SUB-ZERO THROUGH THE DAY...DESPITE MOSTLY SUNNY SKIES. ATTENTION THEN TURNS TO ANOTHER STRONG SHORT WAVE TROUGH DIGGING FROM MANITOBA INTO ONTARIO AND ACROSS THE NORTHERN LAKES INTO TUESDAY...WHICH RESULTS IN DEEP SURFACE LOW PRESSURE PASSING NORTHEAST OF THE GREAT LAKES MONDAY NIGHT AND TUESDAY AND TIGHTENING OF THE SURFACE PRESSURE GRADIENT ACROSS THE MIDWEST. WEST-SOUTHWEST WINDS WILL BECOME BLUSTERY MONDAY NIGHT SUPPORTING STEADY OR SLOWLY RISING TEMPERATURES MONDAY NIGHT ESPECIALLY ACROSS THE NORTH WHERE WINDS WILL BE STRONGEST. TEMPERATURES WILL RISE INTO THE 25-30 DEGREE RANGE DURING THE DAY TUESDAY BEFORE THE COLD FRONT TRAILING THE CANADIAN LOW MOVES THROUGH LATE IN THE DAY...THOUGH THE GUSTY SOUTHWEST WINDS TO 35 MPH AT TIMES WILL MAINTAIN A RAW FEEL TO THE DAY WITH WIND CHILLS IN THE TEENS AT BEST (ABOVE ZERO AT LEAST). CLOUDS WILL INCREASE TUESDAY MORNING AHEAD OF THE APPROACHING FRONT WITH SCATTERED SNOW SHOWERS OR FLURRIES AT TIMES DURING THE DAY. THE COLD FRONT MOVES THROUGH BY EARLY TUESDAY EVENING...WITH BLUSTERY NORTHWEST WINDS BRINGING COLDER AIR BACK INTO THE REGION AT LEAST IN A GLANCING NATURE INTO WEDNESDAY WITH SINGLE DIGIT TEMPS TUESDAY NIGHT AND HIGHS IN THE TEENS AND WIND CHILLS IN THE POSITIVE SINGLE DIGITS WEDNESDAY. A WEAK CLIPPER SYSTEM IS CURRENTLY PROGGED TO MOVE JUST WEST OF THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT...WHICH MAY BRING SOME LIGHT SNOW TO WESTERN PARTS OF THE CWA. LOW LEVEL WINDS ALSO LOOK TO VEER MORE NORTH-NORTHEAST WHICH MAY BRING SOME LIGHT SNOW SHOWERS INTO NORTHWEST INDIANA AND EVEN PARTS OF NORTHEAST ILLINOIS. NOT TOO EXCITED ABOUT ACCUMULATIONS WITH LAKE EFFECT AT THIS TIME...AS INVERSION HEIGHTS REMAIN FAIRLY LOW. RATZER && .LONG TERM... 234 PM CST THURSDAY THROUGH SUNDAY... REINFORCEMENT OF ARCTIC AIR CONTINUES THURSDAY AND THURSDAY NIGHT AS ANOTHER SHORT WAVE TROUGH DIGS SOUTHEAST AND MAINTAINS DEEP LARGE SCALE TROUGH OVER THE EASTERN CONUS. SURFACE HIGH BUILDS SOUTHEAST FROM THE NORTHERN PLAINS THURSDAY...INTO DOWNSTATE ILLINOIS BY FRIDAY MORNING. 850 HPA TEMPS DROP INTO THE -16 TO -20 C RANGE DURING THE PERIOD WITH LIGHT WINDS OF THE SURFACE RIDGE AND CLEARING SKIES AGAIN EXPECTED TO PRODUCE SUB-ZERO TEMPERATURES BY SUNRISE FRIDAY MORNING AND HIGHS ONLY IN THE TEENS FRIDAY...WHICH FOR THE END OF FEBRUARY IS A GOOD 20-25 DEGREES BELOW OUR NORMAL HIGHS WHICH WOULD BE NEAR 40 FOR THE END OF THE MONTH. LONGER RANGE MODEL SOLUTIONS DO OFFER SOME HOPE FOR A LITTLE MODERATION IN TEMPERATURES NEXT WEEKEND...WITH A TROUGH ELONGATING AND BECOMING CUT-OFF IN THE SOUTHWEST CONUS AND A BROAD UPPER RIDGE DEVELOPING ACROSS THE SOUTHEASTERN CONUS SATURDAY AND SUNDAY. THUS OUR ARCTIC HIGH EVENTUALLY MOVES OFF THE ATLANTIC COAST WITH SOUTHERLY FLOW DEVELOPING ACROSS THE LOWER AND MIDDLE MISSISSIPPI VALLEY BY SUNDAY. OF COURSE THIS HELPS TO FEED MILDER AND MORE HUMID AIR NORTHWARD...FOR A NORTHERN STREAM UPPER TROUGH AND SURFACE LOW WHICH WOULD ALSO BRING PRECIPITATION TO THE AREA SATURDAY NIGHT AND SUNDAY. AT THIS DISTANCE HAVE MAINTAINED A CONSERVATIVE APPROACH WITH TEMPS INTO THE MID-30S SUNDAY AND POTENTIAL FOR SOME SNOW... THOUGH IF THESE MODEL TRENDS PERSIST IT COULD BE MILDER WITH MIXED PRECIP OR RAIN ESPECIALLY ACROSS OUR SOUTHEAST. RATZER && .CLIMATE... RECORD COLD TEMPERATURES ARE POSSIBLE IN ROCKFORD ON MONDAY FEBRUARY 23RD. RECORD LOW FOR 2/23: -12 IN 1910. RECORD LOW MAX FOR 2/23: 17 IN 1934. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * NONE IZZI //DISCUSSION...UPDATED 00Z... VFR CONDITIONS WITH NO SIGNIFICANT WINDS THROUGH TAF CYCLE. IZZI //ORD AND MDW CONFIDENCE...UPDATED 03Z... * HIGH CONFIDENCE IN ALL FORECAST ELEMENTS IZZI //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY...STRONG/GUSTY SW WINDS. MVFR CIGS POSSIBLE LATE. WEDNESDAY THROUGH SATURDAY...PRIMARILY VFR. IZZI && .MARINE... 332 PM CST HIGH PRESSURE MOVING ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST THIS AFTERNOON INTO THE EVENING IS ALLOWING FOR NORTHERLY WINDS OF 15 TO 25 KT TO CONTINUE THIS AFTERNOON...WITH THESE SPEEDS TO LIKELY CONTINUE FOR MUCH OF TONIGHT. THIS HIGH WILL DRIFT SOUTHEAST THROUGH THE UPPER MIDWEST AND MID MISSISSIPPI VALLEY TONIGHT THROUGH MONDAY AND THEN REACH THE MID ATLANTIC WEST TO THE SOUTHERN PLAINS BY EARLY TUESDAY MORNING. AS THIS OCCURS...WINDS WILL TURN WEST AND THEN SOUTHWEST SLIGHTLY DIMINISHING ON MONDAY MORNING...BUT THEN INCREASE ONCE AGAIN MONDAY AFTERNOON WITH TO 30 KT WINDS LIKELY LATE IN THE AFTERNOON. WINDS WILL REALLY INCREASE MONDAY NIGHT INTO TUESDAY OUT AHEAD OF SOUTHWARD MOVING LOW PRESSURE OVER ONTARIO...WITH GALES LIKELY. HAVE ISSUED A GALE AND FREEZING SPRAY WARNING OVER THE ENTIRE LAKE MONDAY NIGHT THROUGH TUESDAY NIGHT AND HAVE NOT ISSUED A GALE WARNING FOR THE NEARSHORE AT THIS TIME. HOWEVER...THEY DO APPEAR TO BE A POSSIBILITY VERY EARLY TUESDAY MORNING AND WILL NEED TO CONTINUE MONITORING THIS PERIOD FOR POSSIBLE PREVAILING GALES...AND EVEN FOR A LONGER DURATION. DO HAVE HIGH CONFIDENCE WITH THE START TIME OF THE GALES ACROSS THE LAKE BUT HAVE LOWER CONFIDENCE WITH THE END TIME...WITH THE GALES POSSIBLY LASTING LONGER INTO TUESDAY NIGHT. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039...MIDNIGHT MONDAY TO 9 AM MONDAY. IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011- INZ019...MIDNIGHT MONDAY TO 9 AM MONDAY. LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM MONDAY TO 3 AM WEDNESDAY. HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ669-LMZ671-LMZ673- LMZ675-LMZ777-LMZ779-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM MONDAY TO 3 AM WEDNESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567- LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY. HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366- LMZ563-LMZ565-LMZ567-LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY. SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 10 PM SUNDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 535 PM CST Sun Feb 22 2015 .SHORT TERM...(Tonight) ISSUED AT 240 PM CST SUN FEB 22 2015 Another Arctic air mass settling into our area for tonight and Monday bringing bitterly cold wind chills tonight through the mid-morning hours of Monday with values in the -15 to -25 degree range. Latest upstream observations mostly in the single digits across north central through northeast Iowa with wind gusts up to 30 mph at times. Early morning lows are expected to dip to -2 in the far south to as low as -8 across the north just before dawn Monday. The center of the Arctic high is forecast by models to drift into southeast Iowa by 12z Monday with the surface ridge axis extending northeast into northern Illinois. Forecast soundings and the latest HRRR model suggests the cloud cover we have over the area this afternoon will drift east and south later this evening with mainly some cirrus for the first half of the night and then a mostly clear sky is expected after midnight most areas. Current Wind Chill Advisory will remain in place for late tonight through 9AM Monday morning. && .LONG TERM...(Monday through Sunday) ISSUED AT 240 PM CST SUN FEB 22 2015 As the center of the cold air mass drifts across the area tomorrow, look for winds to diminish during the day but temperatures will be slow to rise with afternoon highs struggling to 10 to 15. The high should be moving off to our east by afternoon and early evening with our next surface low and cold front tracking across southern Canada southwest through the Northern Plains. Early in the evening, surface winds will be light enough for our usual tank with early evening temperatures before we see a steady or slowly rising trend across the north and west, while further east with a lighter wind flow, early morning lows will dip several degrees below zero Monday night into Tuesday morning. As the deep surface low tracks north of Lake Superior on Tuesday, a gusty south to southwest wind should help the mercury climb into the mid 20s far east to the low to mid 30s far west where we should be able to mix out fairly well during the afternoon. With the better upper forcing remaining well to our north and very limited moisture, models not showing much if any precip associated with the boundary as it swings across our area late in the day, except for the GFS which continues to produce a large area of 0.01 qpf with this system. Not worth much more than a chance for flurries and will continue with that for later in the day on Tuesday. Then we will see another cold air mass build gradually southeast thru midweek. The GFS and latest ECMWF continue to show a weak shortwave racing southeast into the Plains on Wednesday along the periphery of the next batch of cold air for the remainder of the work week. The GFS keeps any precip associated with this wave to our west and south while the latest ECMWF has trended in that direction as well but does bring in some light QPF late Wednesday/Wednesday evening. Based on the latest westward shift with the ECMWF, will only have slight chances Wednesday night for light snow. Colder temperatures filter into the area again Wednesday night with early morning lows dropping into the single digits with wind chills dropping to near -10 by Thursday morning. And a real surprise here, the well below normal temperatures are expected to hold on across our area through at least the end of the work week with daytime highs in the teens and early morning lows dropping into the single digits with a few below zero readings again possible early Friday morning. Both the GFS and ECMWF indicate a significant change to the upper pattern with more of a southwesterly flow developing over the weekend which will lead to an increasing threat for precipitation. Models showing more agreement from what we saw yesterday with snow chances moving in starting on Saturday night with the threat for snow or rain on Sunday with warming temperatures. Even seeing some better agreement with the ensemble members with respect to the pattern change along with timing of the precip into our area later Saturday through Sunday. Temperatures will start to turn around on Saturday and Sunday, but still average below the normal highs of 40 to 45 across the area for late February. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 531 PM CST SUN FEB 22 2015 VFR aviation weather Condtions are expected to prevail across the central Illinois terminals through the 00Z TAF valid time. Mid/high level CIGS will gradually diminish with time, with mostly clear skies expected by midday Monday. Northerly breezes from 10-15 kts tonight will become light/variable by Monday afternoon as high pressure builds across the area. && .ILX WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY from Midnight tonight to 9 AM CST Monday FOR ILZ027>031-036>038-040>057-061>063-066>068-071>073. && $$ SHORT TERM...Smith LONG TERM...Smith AVIATION...Bak
AREA FORECAST DISCUSSION
NWS TOPEKA KS
229 PM CST Sat Feb 21 2015 .SHORT TERM...(This Evening through Sunday) Issued at 227 PM CST SAT FEB 21 2015 20Z water vapor shows a broad and deep upper trough centered over the Hudson bay and encompassing much of North America. A couple shortwaves within the upper trough were noted over Alberta Canada and the Pacific Northwest moving south. At the surface, observations show another 1044 MB ridge of high pressure over Alberta poised to move south into the plains. For tonight and Sunday, models agree that cold air advection will increase as MSLP rises in response the the Arctic airmass moving south. This is also expected to increase mid level frontogenesis from the central Rockies into central KS. Both the NAM and GFS show the frontogenetical band extending into parts of northeast KS late tonight with reasonable mid level saturation. However it appears as though the models fail to generate much QPF due to dry air in the lower atmosphere. Feel like there is enough of a signal from the frontogenesis to maintain a chance for measurable snow late tonight and into Sunday morning. The better chances will be along and southwest of a line from Concordia to Emporia. Have kept the forecast dry across northeast KS where the low level dry air is progged to be deeper. Limited moisture and the brief period of vertical motion with the front suggests any snow accumulation will be light and the forecast generally keeps amounts from around a half inch to a dusting. With the pressure gradient remaining fairly strong overnight, there should be reasonable mixing of the boundary layer as surface winds remain in the 10 to 15 MPH range. This combined with increasing cloud cover is expected to prevent lows from plummeting tonight. The forecast has temps falling into the teens by Sunday morning. Continued cold air advection and limited insolation for Sunday should hold afternoon highs in the upper teens to mid 20s. .LONG TERM...(Sunday Night through Saturday) Issued at 227 PM CST SAT FEB 21 2015 Active upper air pattern in the extended term as a series of systems dive south across the western CONUS, and track east towards the Plains. Before this occurs, strong high pressure builds into far northeast Kansas Monday morning as winds become calm. Sided closer to MOS guidance as they appeared to have a better handle on the depth of the cold air with this high. Cloud cover depth will also be slowly diminishing by morning so will keep readings in the single digits, perhaps closer to 0 in far northeast areas in vicinity of the ridge axis. Wind chill readings average from 0 degrees to 7 below zero. Temps gradually recover by Tuesday as warm advection increases from the southwest under mostly sunny skies. Based on model handling on today`s forecast, temps could easily be a tad warmer than current thinking in the lower to middle 40s. Next cold front arrives late Tuesday evening into Wednesday before a elongated shortwave trough tracks southeast from the Pac NW. Latest runs of the GEM, GFS, and ECMWF remain persistent in light snow developing Wednesday afternoon and exiting southward Thursday morning along an axis of mid level frontogenesis. The system is progressive while available moisture is low with the very cold air mass in place; higher snow to liquid ratios however suggest the potential for light snowfall accumulations during this time. An additional kicker shortwave trough follows for Friday and Saturday, lifting an additional PV anomaly through the CWA. Confidence is lower in this system as the GFS is quicker and therefore weaker than the slower ECMWF. Nonetheless, kept the slight to low end chances for light snow across the area during this period. Persistent cold advection from the north and east Wednesday through Saturday will hold highs to the 20s and low 30s with overnight lows in the teens to single digits. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1110 AM CST SAT FEB 21 2015 Don`t have much confidence in the NAM and RAP forecast soundings since they suggest there should be broken MVFR CIGS now. As usual, the NAM is probably overdoing the boundary layer moisture thinking there is snow on the ground. Therefore will follow the GFS and maintain a VFR forecast through the night. If low levels do end up to me more saturated, there may be a small chance for some light snow at MHK late tonight. Will have to continue monitoring boundary layer conditions through the afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...Bowen AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1110 AM CST Sat Feb 21 2015 .UPDATE... Issued at 1110 AM CST SAT FEB 21 2015 The cold air advection is obviously not as strong as previously forecast as temps climb into the mid 40s. Even areas where there is snow from last night are already in the upper 30s to around 40. There is also quite a but more insolation than anticipated. The RAP mixes the boundary layer to about 875MB. Will use this as a first iteration in raising max temps up this afternoon. Also with pretty high based clouds across north central KS, think flurries this afternoon are less likely than if steep low level lapse rates with a stratocu deck around 3 KFT were occurring. && .SHORT TERM...(Through Today) Issued at 252 AM CST SAT FEB 21 2015 Early this morning, widespread light to, at times, moderate precipitation had overspread much of the forecast area, but has been quickly diminishing from west to east through the overnight hours. This precipitation was predominantly in the form of rain and freezing rain with sleet and snow mixing in at times. As of 09Z, precipitation was focused primarily along and southeast of I-35 with a few areas of patchy drizzle/freezing drizzle along and east of a line from Abilene to Marysville, but according to radar returns this light precipitation was very isolated. Based on the short-range model and radar trends, the bulk of the precipitation should move east of the area by 5am with some lingering light precipitation and/or drizzle/freezing drizzle continuing through 7am. As of 09Z, most locations across the forecast area had temperatures of 32-34F. Most locations should stay at or near freezing through sunrise, but cannot rule out temperatures in north central Kansas dropping a bit below freezing as the clouds begin to scatter out some. With temperatures near or slightly below freezing, dangerous travel conditions will continue into the morning hours as wet roads may become more icy. The good news is that temperatures should rise above freezing by 9am to 11am. Despite light northerly winds through the day, models show a nose of warm air extending northward into central and east central Kansas. With model soundings showing cloud cover scattering out this morning and mid/high clouds not building back in until late afternoon or early evening, expect high temperatures to reach into the mid 30s to around 40 degrees from northeast to southwest. .LONG TERM...(Tonight through Friday) Issued at 252 AM CST SAT FEB 21 2015 Overnight tonight, a significant snow event will be ongoing in western Kansas, with the eastern fringe of that light snow coming close to the highway 81 corridor. There is some weak vertical motion in the mid levels in central KS, and forecast soundings indicate steep boundary layer lapse rates with weak instability as well as a deep dendritic growth zone. However, the moisture seems to be lacking. Decided to go with a 30% or less chance of actual accumulating snow showers in the western part of the forecast area, but if the lift is slightly stronger it would result in better saturation and at least some potential for minor snow accumulations through Sunday morning. Clouds are expected to moderate overnight low temperatures despite cold advection, with nearly steady or slightly rising temperatures during the day on Sunday. Sunday night then looks to be quite cold as strong surface high pressure builds overhead...with the main uncertainty in just how cold it will get being determined by cloud cover. Clear skies suggest current forecast of lower single digits may be too warm while cloudy skies would suggest a warmer forecast is warranted. A warming trend is in store by Tuesday with sunshine in the forecast and highs into the 40s. Wednesday will bring another cold front and a sharp cool down while the next chance for winter weather arrives Wednesday night. The forcing mechanisms are a combination of weak short wave energy ejecting from the Rocky Mountain trough, a steadily progressing band of frontogenesis, and isentropic ascent. Model agreement is strong regarding potential for a few inches of accumulating snowfall, possibly encompassing much of the forecast area. However, given recent poor model performance in this flow pattern, would rather not get into the details of system expectations at this time and instead focus on potential for accumulating snow. Of increasing interest at the very end of the forecast period, next weekend, is a potentially more organized trough to move into the Central Plains states...and could lead to additional accumulating winter precip. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1110 AM CST SAT FEB 21 2015 Don`t have much confidence in the NAM and RAP forecast soundings since they suggest there should be broken MVFR CIGS now. As usual, the NAM is probably overdoing the boundary layer moisture thinking there is snow on the ground. Therefore will follow the GFS and maintain a VFR forecast through the night. If low levels do end up to me more saturated, there may be a small chance for some light snow at MHK late tonight. Will have to continue monitoring boundary layer conditions through the afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...Wolters SHORT TERM...Hennecke LONG TERM...Barjenbruch AVIATION...Wolters
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1045 PM MST FRI FEB 20 2015 .UPDATE... ISSUED AT 1045 PM MST FRI FEB 20 2015 UPDATE TO FORECAST SENT TO UPDATE TIMING ONGOING WINTER STORM WARNING...ADJUST CLOUDS/TEMPS FROM LATEST OBS...AND TO REMOVE MENTION OF -RW WORDING TO MAKE ALL -SW/ TEMPS OVER PAST FEW HOURS HAVE DROPPED A FEW DEGREES...COLD ENOUGH TO MAKE ALL -SW THRU REST OF THE OVERNIGHT HOURS. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 220 PM MST FRI FEB 20 2015 VISIBLE SATELLITE IMAGERY WAS INDICATING PARTLY TO MOSTLY CLOUDY SKIES OVER THE TRI STATE AREA IN THE EARLY AFTERNOON...WITH RADAR INDICATING SOME LIGHT PRECIPITATION BEGINNING TO OCCUR IN CENTRAL NEBRASKA AND EASTERN COLORADO AHEAD OF AN UPPER LEVEL SHORTWAVE TROUGH. WATER VAPOR IMAGERY SHOWED A STEADY STREAM OF MOISTURE THAT WILL MOVE INTO THE FORECAST AREA TONIGHT...WHICH WILL BRING OVERCAST SKIES AND CHANCES FOR PRECIPITATION. HRRR AND RAP FORECASTS SHOW LIGHT RAIN SHOWERS BEGINNING TO AFFECT EASTERN COLORADO BETWEEN THE 21Z AND 00Z TIME PERIOD TONIGHT...AND THEN GRADUALLY SPREADING IN COVERAGE OVER NORTHWEST KANSAS. RAIN WILL TRANSITION TO A RAIN/SNOW MIX AROUND 3Z...AND THEN TURN TO ALL SNOW AFTER 6Z. PRECIPITATION AREA WILL ENTER A DRY PERIOD SHORTLY AFTER 6Z AND LAST THROUGH 18Z SATURDAY WHERE VERY LIGHT SNOW ACCUMULATIONS WILL OCCUR...IF ANY. MODEL GUIDANCE WAS SHOWING ANYWHERE FROM A HALF INCH UP TO 2 INCHES FOR EASTERN COLORADO ACCUMULATING DURING THE DAY SATURDAY. THE HIGHER GUIDANCES SEEMED TO BE ACCUMULATING SNOW BEFORE THE 850 FREEZING LINE PASSED THROUGH AND THE 1540 LINE FOR THE 850-700 MB THICKNESS...WHICH LED TO THE DECISION TO BRING SNOW AMOUNTS UNDER HALF AN INCH DURING THE DAY SATURDAY. RAIN AND RAIN/SNOW MIXES WILL OCCUR SOUTH OF A LINE FROM CHEYENNE WELLS COLORADO TO TRENTON NEBRASKA SATURDAY AFTERNOON...WITH SNOW NORTH OF THIS LINE. ABOUT ANOTHER HALF OF AN INCH WILL ACCUMULATE FOR EASTERN COLORADO BEFORE 00Z SUNDAY WHERE THE PRECIPITATION WILL ALL CHANGE OVER TO SNOW...WHICH WILL BRING THE GREATER SNOW ACCUMULATIONS HEADING INTO SATURDAY NIGHT. WITH A LACK OF LOWER AND MID LEVEL JET WINDS IN COMBINATION WITH A 8 MB SURFACE PRESSURE GRADIENT...WINDS ARE NOT EXPECTED TO GUST ABOVE 25 MPH DURING THIS PERIOD. THEREFORE...BLOWING SNOW WILL NOT BE AN ISSUE. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 220 PM MST FRI FEB 20 2015 UPPER FLOW WILL BE WESTERLY ACROSS THE CENTRAL PLAINS SATURDAY NIGHT AS THE BROAD TROUGH ELONGATES FROM THE WEST COAST TO THE GREAT LAKES. AS THE TROUGH CONTINUES TO SPLIT ON SUNDAY A RIDGE WILL START AMPLIFYING OVER THE CENTRAL PLAINS. THE RIDGING CONTINUES OVER THE CENTRAL PLAINS MONDAY WITH A LOW OVER THE DESERT SOUTHWEST AND THE OTHER PORTION OF THE TROUGH NORTHEAST OF THE GREAT LAKES. THE MODELS CONTINUE TO SHOW SPLIT FLOW SUNDAY/SUNDAY NIGHT WITH RIDGING OVER THE FA MONDAY. EXPERIENCE WITH THIS PATTERN IS NOT FAVORABLE FOR PRECIPITATION ACROSS THE FA. GOOD DYNAMICS ARE INDICATED FOR SATURDAY NIGHT AS A SHORTWAVE COMES THROUGH THE FLOW. HOWEVER, IT IS DIFFICULT TO JUSTIFY THE LARGE AMOUNTS OF SNOWFALL THE GFS AND NAM ARE PRODUCING FOR THAT 12 HOUR TIME PERIOD WHICH EQUATES TO ABOUT AN INCH PER HOUR FOR THE ENTIRE 12 HOUR PERIOD. PLAN TO GO SOMEWHERE UNDER THOSE AMOUNTS TO OBTAIN A MORE REASONABLE HOURLY SNOWFALL RATE. AT THIS TIME TOTAL SNOWFALL AMOUNTS SHOULD RANGE FROM 2 INCHES NEAR HILL CITY AND MCCOOK TO 5 TO 9 INCHES IN AN AREA SOUTHWEST OF A LINE FROM YUMA COLORADO TO LEOTI KANSAS. THESE AMOUNTS INCLUDE UP TO 3 INCHES FROM SUNDAY THROUGH MONDAY WHICH MAY TURN OUT TO BE LESS THAN THAT IF THE RIDGING MENTIONED ABOVE LIMITS THE SNOWFALL. WIND SPEEDS WILL RANGE FROM 15 TO 25 MPH SATURDAY NIGHT WITH SPEEDS DECREASING SUNDAY/SUNDAY NIGHT. A WINTER STORM WARNING AND WINTER WEATHER ADVISORY HAS BEEN POSTED FOR SATURDAY EVENING THROUGH SUNDAY EVENING. (SEE DETAILS BELOW). MIN TEMPERATURES SATURDAY NIGHT SHOULD BE IN THE TEENS. COLDER MIN TEMPERATURES IN THE SINGLE DIGITS ABOVE ZERO AND LOW TEENS ARE EXPECTED SUNDAY NIGHT. MAX TEMPERATURES WILL BE IN THE TEENS SUNDAY AND AROUND 20 ON MONDAY. IN THE EXTENDED...(MONDAY NIGHT THROUGH FRIDAY)...THE FORECAST WILL BE DRY MONDAY NIGHT AND TUESDAY WITH LACK ANY DYNAMICS UNDER WESTERLY FLOW. THE PART OF THE TROUGH THAT SPLITS OFF OVER THE WEST COAST WILL MOVE INTO THE DESERT SOUTHWEST TUESDAY AND ACROSS THE CENTRAL/SOUTHERN PLAINS WEDNESDAY. THERE WILL BE A CHANCE TO SLIGHT CHANCE OF LIGHT SNOW AS THIS TROUGH MOVES EAST THROUGH FRIDAY. MIN TEMPERATURES MONDAY NIGHT THROUGH WEDNESDAY NIGHT WILL BE IN THE TEENS. MIN TEMPERATURES THURSDAY NIGHT WILL BE IN THE SINGLE DIGITS ABOVE ZERO. MAX TEMPERATURES TUESDAY AND WEDNESDAY SHOULD RANGE FROM THE MID 30S TO 40. MAX TEMPERATURES THURSDAY AND FRIDAY WILL BE IN THE 20S. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1045 PM MST FRI FEB 20 2015 BOTH TAF SITES WILL SEE MAINLY VFR CONDITIONS THRU 19Z-20Z SATURDAY AFTERNOON. LOOKING FOR CEILINGS OVC040-060 WITH VCSH/-SHSN DURING THIS TIME. FROM 19Z-20Z ONWARD...CONDITIONS DETERIORATE AS A MIX OF IFR/MVFR CONDITIONS WILL PREVAIL AS AREAL COVERAGE OF SNOW INCREASES.LOOKING FOR CEILINGS TO RANGE FROM OVC012-025 AND VISIBILITY RANGING FROM 1 1/2SM TO 5SM AT TIMES. WORSE CONDITIONS AFTER 00Z SUNDAY. NNW WINDS 5-10KTS WILL SHIFT TO WNW BY 10Z SAT...THEN SHIFT TO ENE 10-20KTS BY 19Z-20Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO MIDNIGHT CST SUNDAY NIGHT FOR KSZ001-002-014-015-028-029. WINTER STORM WARNING FROM 5 PM MST /6 PM CST/ SATURDAY TO 11 PM MST /MIDNIGHT CST/ SUNDAY FOR KSZ013-027-041-042. CO...WINTER STORM WARNING FROM 5 PM SATURDAY TO 11 PM MST SUNDAY FOR COZ090>092. NE...WINTER WEATHER ADVISORY FROM 5 PM MST /6 PM CST/ SATURDAY TO 11 PM MST /MIDNIGHT CST/ SUNDAY FOR NEZ079-080. && $$ UPDATE...JN SHORT TERM...MK LONG TERM...FS AVIATION...JN
AREA FORECAST DISCUSSION
NWS PADUCAH KY
550 PM CST SUN FEB 22 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 235 PM CST SUN FEB 22 2015 MAIN ISSUE OF CONCERN IN THE SHORT TERM IS THE WIND CHILL ADVISORY FOR LATE TONIGHT INTO MONDAY MORNING. THE LATEST SHORT TERM GUIDANCE KEEPS THE STRONGEST WINDS AND COLDEST TEMPERATURES ACROSS PORTIONS OF SOUTHEAST MISSOURI AND MOST OF SOUTHERN ILLINOIS. AFTER COLLABORATING WITH WFOS LSX AND LMK DECIDED TO EXPAND THE ADVISORY A ROW OF COUNTIES FARTHER SOUTH ACROSS ILLINOIS AND THEN FROM PERRY SOUTHWARD THROUGH SCOTT AND STODDARD IN MISSOURI. IT LOOKS A LITTLE FUNKY IN MISSOURI...BUT THAT IS DUE TO THE CORE OF STRONGER WINDS IN THAT REGION. THE WIND CHILLS CURRENTLY FORECAST OVER SOUTHWEST INDIANA AND ADJACENT PORTIONS OF WEST KENTUCKY DO NOT QUITE GET DOWN TO 10 BELOW...BUT LEFT THAT ALONE BECAUSE IT WILL BE CLOSE. ALTHOUGH WINDS ARE EXPECTED TO BE LIGHT MONDAY NIGHT...SOUTH WINDS WILL INCREASE QUICKLY TUESDAY MORNING AND WITH THE LOWS WELL INTO THE SINGLE DIGITS...MUCH OF SOUTHERN ILLINOIS AND SOUTHWEST INDIANA MAY SEE SOME NEGATIVE WIND CHILLS FOR A FEW HOURS TUESDAY MORNING. WILL GIVE THIS A MENTION IN THE HWO. KEPT A MENTION OF FLURRIES IN THE FORECAST LATE THIS AFTERNOON AND EVENING ROUGHLY ALONG AND SOUTH OF A LINE FROM VAN BUREN MISSOURI TO MURRAY KENTUCKY. THE HRRR AND WRF RUNS REALLY DRY UP ANY ECHOES AS THEY ENTER OUR AREA...AND THERE HASN`T BEEN ANY REPORTS OF SNOW REACHING THE GROUND THIS SIDE OF KJLN. WON`T BE COMPLETELY SURPRISED TO SEE A FEW FLURRIES...BUT MEASURABLE SNOWFALL IS HIGHLY UNLIKELY. TEMPERATURES HAVE REMAINED NEARLY STEADY ACROSS THE REGION TODAY. FIGURE THAT COLD ADVECTION WILL KICK IN AS WE HEAD INTO THE EVENING HOURS...BUT ENDED UP RAISING LOWS A BIT FOR TONIGHT. MOS GUIDANCE IS GIVING QUITE A RANGE FOR FIRST PERIOD LOWS. LOOKING UPSTREAM THIS AFTERNOON...IT APPEARS THAT GUIDANCE FOR HIGHS ON MONDAY IS A BIT TOO COLD. LEANED TOWARD THE LESS COLD NAM/MET NUMBERS...BUT IT WILL STILL STRUGGLE TO GET THROUGH THE TEENS IN MOST LOCATIONS. WIND CHILLS WILL REMAIN IN THE SINGLE DIGITS ABOVE ZERO THROUGH THE AFTERNOON. NOT SURE IF MID/HIGH CLOUDS WILL BE THICK ENOUGH TO HOLD TEMPERATURES UP MUCH MONDAY NIGHT OR NOT. WINDS SHOULD BE LIGHT OR CALM WITH HIGH PRESSURE OVERHEAD...SO IT WILL BE ANOTHER COLD ONE. DEFINITELY WENT TO THE COLD SIDE OF GUIDANCE MONDAY NIGHT. SOUTHWEST WINDS WILL INCREASE ACROSS THE AREA TUESDAY...SO A DECENT WARM UP IS FORECAST. UNFORTUNATELY WITH TEMPERATURES STARTING OFF SO COLD...IT WILL STRUGGLE TO GET TO THE FREEZING MARK. A DISTURBANCE WILL DIVE SOUTHEAST THROUGH THE GREAT LAKES TUESDAY NIGHT. THIS WILL BRING AN INCREASE IN CLOUDS AND A WEAK COLD FRONTAL PASSAGE THROUGH OUR REGION. LOWS TUESDAY NIGHT WILL ACTUALLY BE MILD...RELATIVELY SPEAKING. SOME LOCATIONS WILL STAY ABOVE 20 ALL NIGHT. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 235 PM CST SUN FEB 22 2015 ANOTHER SURGE OF COLD HIGH PRESSURE WILL BUILD SOUTHEAST WEDNESDAY INTO WEDNESDAY NIGHT BEHIND A WEAK COLD FRONT. THE CENTER OF THE HIGH WILL MOVE SOUTHEAST THROUGH THE END OF THE WORK WEEK AND SETTLE OVER THE OHIO VALLEY BY 00Z SATURDAY. TEMPERATURES WILL AGAIN DROP OFF TO EVEN COLDER THAN SEASONAL NORMALS, WITH HIGHS THURSDAY AND FRIDAY ONLY IN THE 20S WITH LOWS IN THE SINGLE DIGITS TO MIDDLE TEENS. MODELS SHOW THE HIGH DRIFTING EASTWARD FOR THE EARLY PART OF THE WEEKEND. TEMPERATURES WILL MODERATE BACK IN THE 30S AHEAD OF OUR NEXT WEATHER SYSTEM. ECMWF AND GFS DIFFER ON TIMING AND TRACK OF A LOW PRESSURE SYSTEM, WITH ECMWF BEING THE FASTER OF THE MODELS WITH MORE SUBSTANTIAL QPF. ECMWF SHOWS WIDESPREAD PRECIPITATION ACROSS THE PAH FORECAST AREA SATURDAY NIGHT, WHILE GFS JUST SHOW MINIMAL QPF REACHING INTO OUR SOUTHERN COUNTIES LATE SATURDAY NIGHT. BY SUNDAY BOTH MODELS SHOW DECENT QPF ACROSS THE ENTIRE PAH FA. JUST WENT WITH SLIGHT CHANCE POPS FOR LIGHT SNOW SATURDAY NIGHT, INCREASING TO CHANCE POPS FOR RAIN ON SUNDAY. BOTH MODELS YESTERDAY SHOWED THIS SYSTEM AFFECTING OUR REGION FRIDAY NIGHT INTO SATURDAY, SO WE STILL ARE FAIRLY LOW CONFIDENCE ON TIMING. THE LATER TIMING DOES AT LEAST ALLOW SOME "WARMER" TO GET INTO OUR AREA AHEAD OF THE SYSTEM, THUS LEADING TO LESS WINTRY PRECIP. && .AVIATION... ISSUED AT 550 PM CST SUN FEB 22 2015 BRIEF MVFR CEILINGS AT KOWB AT THE BEGINNING OF THE FORECAST PERIOD ASSOCIATED WITH LIFT TIED WITH THE PASSAGE OF THE ARCTIC SURGE OF COLR AIR...OTHERWISE VFR CONDITIONS SHOULD PREVAIL FOR EACH OF THE WFO PAH TAF SITES THROUGH THE REMAINDER OF THE FORECAST. SHORTENED THE GRADIENT WIND PERIOD ASSOCIATED WITH THE PASSAGE OF THE GRADIENT AT KEVV/KOWB, BUT KEPT GRADIENT WINDS LONGER OVER KCGI/KPAH. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST MONDAY FOR ILZ075>078-080>091. MO...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST MONDAY FOR MOZ076-086-087-110-111. IN...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST MONDAY FOR INZ081-082-085>088. KY...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST MONDAY FOR KYZ010-014-015-018>020. && $$ SHORT TERM...DRS LONG TERM...RST AVIATION...SMITH
AREA FORECAST DISCUSSION...COR TO AVIATION
NWS LOUISVILLE KY
1230 AM EST Sat Feb 21 2015 ...Updated Aviation Discussion... ...Forecast Update... Issued at 1155 PM EST Fri Feb 20 2015 Mix of sleet/snow working northeast through the area, with reports suggesting a bit more sleet than anticipated. Will lean on that dynamic cooling initially will turn things back to snow across the north. To the south, low level jet is ramping up noticeably as slug of moisture streams from the southwest. Concerned that icing accumulations in our south may be too conservative. First, surface temperatures are struggling to rise. 32F line remains back in northern MS/AL with little rise noted so far in TN. 00z guidance, both the NAM and now GFS, show surface temps lagging considerably despite the warming aloft, and really hugs the 32/33F line for a good portion of the morning, after 12z. Will need to evaluate the current WS.W expiration time for the southern areas as well as ice accumulations. Snow forecast amounts in the north look good at this point, so no changes currently needed there. Hydro-wise, we`ll be closely watching things but likely will need a Flood Watch for the southern areas to address increasing concerns for snow melt and heavy rainfall. 3 inch totals are looking more likely, which combined with snow pack and ice accumulation, will make for a messy and hazardous situation. Issued at 1020 PM EST Fri Feb 20 2015 NAM has come in with a more narrow window for sleet/freezing rain, especially along and north of the I-64 corridor. Between 12 and 15Z Saturday it goes back to snow for the Louisville area and continues that way through the daytime period. The 18Z GFS had that area warm, so have kept in a chance for a mix for now. Mid shift can continue trending the forecast as the rest of the models come in and especially as we see the event unfold. Of note, the HRRR is coming in with some higher snow totals than what I have up to the end of its period at 15Z. It has done well so far with the reflectivity field, so something to watch out for overnight. Issued at 700 PM EST Fri Feb 20 2015 Nothing has changed as far as the complexity of this winter system is concerned. Forecast soundings still waffle around the freezing line at various times and depths. No one particular model is handling the current surface temperatures across the region, so what they have aloft is equally in question. One thing we do know is a low-level jet will crank up across the region the rest of the night, with a limit to how far north it can advance based on the position of an 850mb trough swinging in. Should the limit be the I-64 corridor, we could see a longer period of snow/fzra in that vicinity, with more snow to the north then in the current forecast. Have trended the forecast this way, with higher totals in the north. Will continue to make updates with QPF trends and model temp trends as conditions warrant through the night. .SHORT TERM (Now through Saturday Night)... Issued at 344 PM EST Fri Feb 20 2015 ...Extremely Complex Storm System Arrives Tonight Bringing A Wintry Mess To The Region... Arctic high that resulted in us seeing record cold temperatures over the last few days will continue to move eastward this afternoon and evening. In the near term, mostly cloudy skies along with southeasterly breezes will allow temperatures to slowly warm throughout the remainder of the afternoon and evening hours. As expected, the model guidance is running a little too warm with surface temperatures as the snow pack is keeping temperatures down. NWS observations and KY Mesonet readings show temperatures in the mid to upper teens across portions of north-central and east-central KY with lower 20s being reported down near the KY/TN border region. Regional radars showing precipitation developing over AR/MO. Reports from WFO PAH indicate a mix of sleet and snow is being reported with this activity. We expect this precipitation to move east-northeastward and spread into southern KY later this afternoon and evening as we continue to saturate the column from top to bottom. This precipitation is forecast to be in the form of snow, though some sleet could be mixed in initially until we wetbulb down. Surface temperatures are expected to continue to slowly warm into the lower-mid 20s. For tonight, an area of low pressure in OK will move into AR and then move northeastward along and mainly south of the Ohio River and then into Ohio by Saturday evening. A very good fetch of moisture off the Gulf of Mexico will transport copious amounts of moisture into the lower Ohio Valley. In addition to the moisture, the low-level jet will also transport warmer air into the region. This warmer air will move over the top of a pre-existing cold airmass, setting the stage for wintry weather across the region. At this time, a very large amount of uncertainty regarding how the lower level atmospheric temperature profile will evolve this evening. In particular, the effects of a deep snowpack and the ability for the models to accurately forecast the very low-level atmospheric temperatures remains a challenge. Our current thinking is that the impressive low-level jet structure combined with upper level jet energetics will result in good diffluence aloft for large scale synoptic scale lift for moderate to occasionally heavy precipitation. Careful analysis of the thermal profiles suggest that precipitation will initially start off as snow across the region. However, as the jet pushes into the region, a surge of warmer aloft will overspread the region. As is the case in low-level jet structures, the strong air advection appears to be strong enough to over come the snow pack in southern KY resulting in a thermal profile that results in snow changing over to a mix of freezing rain and sleet. Before the snow changes over, some light accumulations, perhaps of 1-2 inches will be possible. Once the change over takes place, moderate to heavy freezing rain with some sleet will lead to some significant ice accumulations across south-central KY. Our forecast is for at least 0.20 to 0.35 inches of freezing rain falling late tonight across southern KY. By late tonight, temperatures are expected to rise above freezing resulting in a final transition to plain rain before sunrise Saturday. In addition, the low-level jet will translate downward in the vertical resulting in increasing southerly winds at the surface. This may result in ice coated tree limbs and power lines to come down late tonight. Further north, the forecast becomes very complicated as the depth of the cold air remains in question. Given the deeper snow pack across this area...and its geographic location within the deeper core of the arctic airmass, it appears that we`ll keep a cold enough profile to keep snow going this evening and into the overnight period before the warmer air aloft pushes thermal profiles warm enough to support mainly liquid type precipitation. Because of the expected longer duration of colder near-surface air, significant sleet and snowfall accumulations are likely in areas along and north of the WK/BG Parkways. Our current thinking is that that 2-4 inches will be possible in areas from near Hartford up through the Elizabethtown region. Further north, and mainly along and north of the I-64 corridor...which includes the Lexington and Louisville metro regions, 4-7 inches with locally higher amounts will be possible. Some light ice accumulations will also be possible...though it appears that the length of mixed precipitation during the anticipated changeover will be quite limited. For Saturday, we expect rain to be in progress across southern KY. Moderate to heavy rainfall will be possible across southern KY. This rain...falling on top of accumulated ice and snow may result in excessive runoff. More details on this can be found in the Hydrology section below. A change over to rain is expected across the region during the morning hours as the low-level warm air becomes quite deep...in response to the strong low-level jet structure. The rain will diminish in intensity during the afternoon as the upper forcing moves east. Colder air will quickly invade from the NW resulting in a change back to snow from NW to SE before ending. Some minor additional snow accumulations will be possible. On a final note, we want to emphasize that forecast confidence with these types of systems is never high. We fully anticipate that adjustments...some possibly significant...may be required in future forecasts as this weather system develops this evening and overnight. We strongly believe that we have put together the best forecast that we can with the current data and forecaster knowledge available. As this system evolves, we will make necessary changes to the forecast. Residents of southern Indiana and central Kentucky should be sure to keep up to date with the latest forecasts this evening and overnight. .LONG TERM (Sunday through Friday)... Issued at 215 PM EST Fri Feb 20 2015 Will keep the long term short and sweet as all focus is on the short term and the potentially significant winter storm to impact the Ohio Valley. This storm will exit the region on Sunday morning, allowing cooler air to once again filter into the region. The Canadian high will build strongly into the Ohio Valley on Monday into Monday night. This will bring the coolest temperatures of the long term period, where highs Monday will struggle in the teens and lows Tuesday morning will likely fall to near zero or below. Temperatures will remain below normal through the rest of the extended, with the next chance for precipitation coming Tuesday night, where a few snow showers may affect areas mainly east of I-65. && .HYDROLOGY... Issued at 310 PM EST Fri Feb 20 2015 A strong low-level push of warmer and very moist air into the lower Ohio Valley will result in a wintry mix changing to periods of moderate and heavy rain Saturday, especially over south-central KY. This could result in flooding issues for the following reasons: 1) Deep snow cover. Snow depths range from 6 to 10 inches and currently contains roughly two-thirds to 1.25 inches of liquid equivalent. 2) Current frost depth. The depth is around 2 inches at this time meaning a solidly frozen ground. This would be more likely to cause runoff as a frozen ground will be very inefficient in absorbing water, especially given high rainfall rates. 3) Expected precipitation amounts. Even with initial precipitation falling as snow, sleet, or freezing rain over south-central KY, warmer surface air along with a changeover to rain should melt this additional wintry precipitation along with some of the ambient snow cover. Total liquid rainfall amounts of 1.5 to 2.5 inches with locally higher amounts are expected across south-central KY. The combination of the above factors could result in flood concerns beginning tonight and lasting into early next week. Areal flooding is possible, especially in low-lying areas, poor drainage areas, and urban locations. In addition, minor flooding could develop on some rivers early next week, such as the Green and Rolling Fork Rivers. The strength and degree of warming with this system will have a major impact on total rainfall amounts, the amount of snow melt, and the overall flood potential. Stay tuned to the latest forecasts. Those with hydro or river interests should monitor this storm system closely. && .AVIATION (06Z TAF Update)... Issued at 1229 AM EST Sat Feb 21 2015 Very complex and low-confidence forecast as the biggest impact will be precipitation types. Bottom line is that a wintry mess is likely, and will affect all 3 terminals but persist for a longer period at SDF and LEX. A variety of winter precipitation will continue through the pre-dawn hours as surface low pressure and an upper wave approach from the west. BWG should see primarily FZRA through dawn, while SDF and LEX sit on the line between FZRA to the south and SNPL to the north. Ceilings and vsbys will be mostly MVFR but some high-end IFR cig is not out of the question. BWG should go over to rain by 12Z or so, and remain there for the rest of the event. The heaviest precipitation across the region will move in around 09Z to 11Z, and will persist until midday as that upper wave moves through and the surface low enters western Kentucky. LLWS will be marginal at SDF and LEX...much stronger at BWG. Will include WS at BWG through the dark morning hours. A few rumbles of thunder will be possible at BWG between 06Z and 08Z, but the chances of anything significant are small enough to omit from the already complicated TAF. Conditions will vastly improve after 22Z-24Z today as the storm system pulls off to the east. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER STORM WARNING until 7 PM EST /6 PM CST/ this evening FOR KYZ023>043-045>049-053>057-065>067. WINTER STORM WARNING until 6 AM CST Saturday FOR KYZ061>064- 070>078-081-082. IN...WINTER STORM WARNING until 7 PM EST /6 PM CST/ this evening FOR INZ076>079-083-084-089>092. && $$ Update.........ZBT/RJS Short Term.....MJ/KJD/BJS Long Term......KJD Hydrology......KJD Aviation.......13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1205 AM EST Sat Feb 21 2015 ...Forecast Update... Issued at 1155 PM EST Fri Feb 20 2015 Mix of sleet/snow working northeast through the area, with reports suggesting a bit more sleet than anticipated. Will lean on that dynamic cooling initially will turn things back to snow across the north. To the south, low level jet is ramping up noticeably as slug of moisture streams from the southwest. Concerned that icing accumulations in our south may be too conservative. First, surface temperatures are struggling to rise. 32F line remains back in northern MS/AL with little rise noted so far in TN. 00z guidance, both the NAM and now GFS, show surface temps lagging considerably despite the warming aloft, and really hugs the 32/33F line for a good portion of the morning, after 12z. Will need to evaluate the current WS.W expiration time for the southern areas as well as ice accumulations. Snow forecast amounts in the north look good at this point, so no changes currently needed there. Hydro-wise, we`ll be closely watching things but likely will need a Flood Watch for the southern areas to address increasing concerns for snow melt and heavy rainfall. 3 inch totals are looking more likely, which combined with snow pack and ice accumulation, will make for a messy and hazardous situation. Issued at 1020 PM EST Fri Feb 20 2015 NAM has come in with a more narrow window for sleet/freezing rain, especially along and north of the I-64 corridor. Between 12 and 15Z Saturday it goes back to snow for the Louisville area and continues that way through the daytime period. The 18Z GFS had that area warm, so have kept in a chance for a mix for now. Mid shift can continue trending the forecast as the rest of the models come in and especially as we see the event unfold. Of note, the HRRR is coming in with some higher snow totals than what I have up to the end of its period at 15Z. It has done well so far with the reflectivity field, so something to watch out for overnight. Issued at 700 PM EST Fri Feb 20 2015 Nothing has changed as far as the complexity of this winter system is concerned. Forecast soundings still waffle around the freezing line at various times and depths. No one particular model is handling the current surface temperatures across the region, so what they have aloft is equally in question. One thing we do know is a low-level jet will crank up across the region the rest of the night, with a limit to how far north it can advance based on the position of an 850mb trough swinging in. Should the limit be the I-64 corridor, we could see a longer period of snow/fzra in that vicinity, with more snow to the north then in the current forecast. Have trended the forecast this way, with higher totals in the north. Will continue to make updates with QPF trends and model temp trends as conditions warrant through the night. .SHORT TERM (Now through Saturday Night)... Issued at 344 PM EST Fri Feb 20 2015 ...Extremely Complex Storm System Arrives Tonight Bringing A Wintry Mess To The Region... Arctic high that resulted in us seeing record cold temperatures over the last few days will continue to move eastward this afternoon and evening. In the near term, mostly cloudy skies along with southeasterly breezes will allow temperatures to slowly warm throughout the remainder of the afternoon and evening hours. As expected, the model guidance is running a little too warm with surface temperatures as the snow pack is keeping temperatures down. NWS observations and KY Mesonet readings show temperatures in the mid to upper teens across portions of north-central and east-central KY with lower 20s being reported down near the KY/TN border region. Regional radars showing precipitation developing over AR/MO. Reports from WFO PAH indicate a mix of sleet and snow is being reported with this activity. We expect this precipitation to move east-northeastward and spread into southern KY later this afternoon and evening as we continue to saturate the column from top to bottom. This precipitation is forecast to be in the form of snow, though some sleet could be mixed in initially until we wetbulb down. Surface temperatures are expected to continue to slowly warm into the lower-mid 20s. For tonight, an area of low pressure in OK will move into AR and then move northeastward along and mainly south of the Ohio River and then into Ohio by Saturday evening. A very good fetch of moisture off the Gulf of Mexico will transport copious amounts of moisture into the lower Ohio Valley. In addition to the moisture, the low-level jet will also transport warmer air into the region. This warmer air will move over the top of a pre-existing cold airmass, setting the stage for wintry weather across the region. At this time, a very large amount of uncertainty regarding how the lower level atmospheric temperature profile will evolve this evening. In particular, the effects of a deep snowpack and the ability for the models to accurately forecast the very low-level atmospheric temperatures remains a challenge. Our current thinking is that the impressive low-level jet structure combined with upper level jet energetics will result in good diffluence aloft for large scale synoptic scale lift for moderate to occasionally heavy precipitation. Careful analysis of the thermal profiles suggest that precipitation will initially start off as snow across the region. However, as the jet pushes into the region, a surge of warmer aloft will overspread the region. As is the case in low-level jet structures, the strong air advection appears to be strong enough to over come the snow pack in southern KY resulting in a thermal profile that results in snow changing over to a mix of freezing rain and sleet. Before the snow changes over, some light accumulations, perhaps of 1-2 inches will be possible. Once the change over takes place, moderate to heavy freezing rain with some sleet will lead to some significant ice accumulations across south-central KY. Our forecast is for at least 0.20 to 0.35 inches of freezing rain falling late tonight across southern KY. By late tonight, temperatures are expected to rise above freezing resulting in a final transition to plain rain before sunrise Saturday. In addition, the low-level jet will translate downward in the vertical resulting in increasing southerly winds at the surface. This may result in ice coated tree limbs and power lines to come down late tonight. Further north, the forecast becomes very complicated as the depth of the cold air remains in question. Given the deeper snow pack across this area...and its geographic location within the deeper core of the arctic airmass, it appears that we`ll keep a cold enough profile to keep snow going this evening and into the overnight period before the warmer air aloft pushes thermal profiles warm enough to support mainly liquid type precipitation. Because of the expected longer duration of colder near-surface air, significant sleet and snowfall accumulations are likely in areas along and north of the WK/BG Parkways. Our current thinking is that that 2-4 inches will be possible in areas from near Hartford up through the Elizabethtown region. Further north, and mainly along and north of the I-64 corridor...which includes the Lexington and Louisville metro regions, 4-7 inches with locally higher amounts will be possible. Some light ice accumulations will also be possible...though it appears that the length of mixed precipitation during the anticipated changeover will be quite limited. For Saturday, we expect rain to be in progress across southern KY. Moderate to heavy rainfall will be possible across southern KY. This rain...falling on top of accumulated ice and snow may result in excessive runoff. More details on this can be found in the Hydrology section below. A change over to rain is expected across the region during the morning hours as the low-level warm air becomes quite deep...in response to the strong low-level jet structure. The rain will diminish in intensity during the afternoon as the upper forcing moves east. Colder air will quickly invade from the NW resulting in a change back to snow from NW to SE before ending. Some minor additional snow accumulations will be possible. On a final note, we want to emphasize that forecast confidence with these types of systems is never high. We fully anticipate that adjustments...some possibly significant...may be required in future forecasts as this weather system develops this evening and overnight. We strongly believe that we have put together the best forecast that we can with the current data and forecaster knowledge available. As this system evolves, we will make necessary changes to the forecast. Residents of southern Indiana and central Kentucky should be sure to keep up to date with the latest forecasts this evening and overnight. .LONG TERM (Sunday through Friday)... Issued at 215 PM EST Fri Feb 20 2015 Will keep the long term short and sweet as all focus is on the short term and the potentially significant winter storm to impact the Ohio Valley. This storm will exit the region on Sunday morning, allowing cooler air to once again filter into the region. The Canadian high will build strongly into the Ohio Valley on Monday into Monday night. This will bring the coolest temperatures of the long term period, where highs Monday will struggle in the teens and lows Tuesday morning will likely fall to near zero or below. Temperatures will remain below normal through the rest of the extended, with the next chance for precipitation coming Tuesday night, where a few snow showers may affect areas mainly east of I-65. && .HYDROLOGY... Issued at 310 PM EST Fri Feb 20 2015 A strong low-level push of warmer and very moist air into the lower Ohio Valley will result in a wintry mix changing to periods of moderate and heavy rain Saturday, especially over south-central KY. This could result in flooding issues for the following reasons: 1) Deep snow cover. Snow depths range from 6 to 10 inches and currently contains roughly two-thirds to 1.25 inches of liquid equivalent. 2) Current frost depth. The depth is around 2 inches at this time meaning a solidly frozen ground. This would be more likely to cause runoff as a frozen ground will be very inefficient in absorbing water, especially given high rainfall rates. 3) Expected precipitation amounts. Even with initial precipitation falling as snow, sleet, or freezing rain over south-central KY, warmer surface air along with a changeover to rain should melt this additional wintry precipitation along with some of the ambient snow cover. Total liquid rainfall amounts of 1.5 to 2.5 inches with locally higher amounts are expected across south-central KY. The combination of the above factors could result in flood concerns beginning tonight and lasting into early next week. Areal flooding is possible, especially in low-lying areas, poor drainage areas, and urban locations. In addition, minor flooding could develop on some rivers early next week, such as the Green and Rolling Fork Rivers. The strength and degree of warming with this system will have a major impact on total rainfall amounts, the amount of snow melt, and the overall flood potential. Stay tuned to the latest forecasts. Those with hydro or river interests should monitor this storm system closely. && .AVIATION (00Z TAF Update)... Issued at 615 PM EST Fri Feb 20 2015 Very complex and low-confidence forecast as the biggest impact will be precipitation types. Bottom line is that a wintry mess is likely, and will affect all 3 terminals but persist for a longer period in SDF and LEX. Precip will move in by mid-evening, initially as snow but eventually mixing with sleet. MVFR conditions will develop, with ceilings going fuel-alternate. Will see the warm nose push in from the south, changing BWG over to freezing rain/sleet mix late evening and SDF and LEX by 07-08Z. The real concern at SDF is that if this does come down as freezing rain, it could be moderate FZRA at times. By the time precip intensity picks up, BWG should be above freezing. Strong low-level jetting will create wind shear issues, but not as bad as it could be as the stronger inversion and most intense low-level jet is above 2000 feet. By around daybreak, look for enough cold air aloft to switch SDF and LEX back to mostly snow, perhaps mixed with sleet. Ceilings will go IFR at that point, but visibilities still look borderline IFR/MVFR. Model solutions diverge from there, as the GFS really erodes the cold air while the NAM keeps surface temps very close to freezing. Carried an indeterminate RASN at both SDF and LEX for most of the afternoon. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...WINTER STORM WARNING until 7 PM EST /6 PM CST/ this evening FOR KYZ023>043-045>049-053>057-065>067. WINTER STORM WARNING until 6 AM CST Saturday FOR KYZ061>064- 070>078-081-082. IN...WINTER STORM WARNING until 7 PM EST /6 PM CST/ this evening FOR INZ076>079-083-084-089>092. && $$ Update.........ZBT/RJS Short Term.....MJ/KJD/BJS Long Term......KJD Hydrology......KJD Aviation.......RAS
AREA FORECAST DISCUSSION...UPDATED
NWS SHREVEPORT LA
1043 AM CST SAT FEB 21 2015 .DISCUSSION... AS OF 16Z...THE COLD FRONT WAS ROUGHLY LOCATED ALONG THE I-30 CORRIDOR. A LINE OF CONVECTION HAS BEEN TRYING TO DEVELOP ALONG AND AHEAD OF THE FRONT FROM NEAR KCRS NEWD TO KTXK AND KLZK. SOME OF THIS CONVECTION...MAINLY IN SRN AND CNTRL AR...IS ACTUALLY BEHIND THE FRONT. SCT SHWRS ALSO PERSIST ACROSS MUCH OF THE CWA WELL IN ADVANCE OF THE MAIN BAND OF TSTMS. COMBINED WITH THE PERSISTENT CLOUD COVER...THIS IS HELPING TO LIMIT INSTABILITY. CONVECTION ALONG THE FRONT WILL LIKELY BE IN A LINEAR MODE TODAY AND A FEW SVR STORMS ARE STILL POSSIBLE WITH DAMAGING WINDS THE PRIMARY THREAT. IF ANY LOCALIZED BACKING OF THE LOW LVL WINDS OCCUR AHEAD OF THE FRONT...AN ISOLATED TORNADO CANNOT BE RULED OUT. HAVE UPDATED MOST OF THE GRIDS THROUGH 00Z BASED ON LATEST FRONT POSITION...OBS AND RADAR TRENDS. UPDATED TEXT PRODUCTS HAVE BEEN SENT. /09/ && .PREV DISCUSSION... /ISSUED 554 AM CST SAT FEB 21 2015/ AVIATION... LOTS OF AVIATION CONCERNS TODAY AND TONIGHT ACROSS OUR TERMINAL LOCATIONS. MVFR CEILINGS ARE THE PREVAILING CATEGORY THIS MORNING AS MOISTURE CONTINUES TO STREAM NORTHWARD WITH THE AID OF 50+ KTS AT 3KFT PER KSHV VWP DATA. ISENTROPIC LIFT IS RESULTING IN SOME DRIZZLE AND/OR LIGHT RAIN IN THE VCNTY OF THE ELD/SHV AND LFK TERMINALS. MEANWHILE...SCATTERED CONVECTION IS BEGINNING TO DEVELOP JUST SOUTH OF A WARM FRONT ACROSS PORTIONS OF NE TX/SE OK AND SW AR IN THE VCNTY OF THE TXK/ELD TERMINALS. HAVE TIMED FRONTAL PASSAGE ACCORDING TO THE LATEST HRRR DATA WHICH SHOWS THE FRONT INTO THE TXK/TYR TERMINALS BY 18Z...INTO THE SHV/ELD TERMINALS BY 21Z AND INTO THE LFK/MLU TERMINALS NEAR THE 00Z HOUR. WINDS AHEAD OF THIS FRONT WILL REMAIN STRONG WITH SUSTAINED WINDS NEAR 15KTS WITH HIGHER GUSTS. GRADIENT ACTUALLY APPEARS TO RELAX SLIGHTLY JUST AHEAD OF FRONTAL PASSAGE. WARM SECTOR WILL BECOME UNSTABLE TODAY AHEAD OF THE FRONTAL BOUNDARY AND WITH FRONTAL FORCING...EXPECT TO SEE A LINEAR LINE OF THUNDERSTORMS DEVELOPING ALONG THE FRONT ITSELF. EXPECT THE POSSIBILITY OF IFR CEILINGS BEHIND THE FRONTAL BOUNDARY LATE TODAY INTO TONIGHT WITH SOME POST FRONTAL CONVECTION AS WELL GIVEN THE FACT THAT THE 850MB FRONT IS MUCH SLOWER TO MOVE INTO THE REGION TONIGHT. 13 PREV DISCUSSION... /ISSUED 447 AM CST SAT FEB 21 2015/ DISCUSSION... NWD MOVG WARM FRONTAL BOUNDARY HAS STALLED OUT FOR TIME BEING...OVER EXTREME NORTHERN TIER OF CWA. COLD AIRMASS EXTREMELY SHALLOW...AS SEEN BY WILD TEMP FLUCTUATIONS WITHIN THE VALLEYS AND RIDGES OF THE OUACHITA MTNS. STG LOW LVL JET OF 50+ KNOTS FROM SW HAS ALLOWED LAKE WIND ADVISORY CRITERIA TO MAINTAIN ACROSS WESTERN CWA OVERNIGHT. WITH SFC TEMPS WARMING TO LOWER TO MID 70S...AND DEWPOINTS TO CONTINUE TO RISE INTO 60S IN WARM SECTOR...EXPECT TSTMS SOUTH OF I-30 TO POSSIBLY BECOME STG AS SOME DIURNAL HTG TO OCCUR BEFORE COLD FRONTAL PASSAGE. THIS FRONT WILL REACH THE I-20 CORRIDOR BY LATE IN AFTN...AND CONVECTION TO TRANSITION TO COLD RAIN WITH FROPA. CLOUDY SKIES AND CAA ON SUNDAY WILL PREVENT MUCH WARMING FROM OCCURRING WITH SAT NIGHT LOWS FALLING MOSTLY INTO UPPER 30S AND LOWER 40S. APPEARS ENOUGH MOISTURE LEFT WITH POST FRONTAL SHORT WAVE ARRIVING SUNDAY NIGHT FOR RAIN TO TRANSITION TO FRZG RAIN IN FALLING TEMPS AND VERY SHALLOW COLD AIRMASS MENTIONED EARLIER. SECOND SHORT WAVE ARRIVING TUESDAY APPEARS TO CONTAIN ENOUGH MOISTURE FOR PRECIP TO CONTINUE. WITH WARM NOSE AND SFC BASED INVERSION WEAKENING BY THEN...BETTER POTENTIAL FOR SNOW AND SLEET...AND SLEET WILL WORK ITS WAY DOWN THRU MOST OF CWA. GFS IS OBVIOUSLY TOO COLD...KEEPING DAYTIME TEMPS IN 20S MOST OF AREA SO LEANING CLOSER TO NAM. DEEPENING UPPER TROUGH TO WEST IN EXTENDED WILL YIELD MORE PRECIP LATER IN WEEK...WHICH MAY WELL ALSO BECOME A WINTRY MIX AS ARCTIC AIRMASS WILL REMAIN ENTRENCHED OVER THE AREA. /VII/. && .PRELIMINARY POINT TEMPS/POPS... SHV 71 42 47 30 34 / 60 40 30 50 60 MLU 70 41 49 29 34 / 70 60 30 50 60 DEQ 61 37 41 24 31 / 50 10 30 50 60 TXK 67 38 43 27 31 / 60 20 30 50 60 ELD 66 37 44 25 31 / 70 40 30 50 60 TYR 66 44 45 31 34 / 40 40 40 50 70 GGG 68 43 46 30 34 / 50 40 40 50 70 LFK 72 50 54 35 37 / 40 40 40 40 70 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 09
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
554 AM CST SAT FEB 21 2015 .AVIATION... LOTS OF AVIATION CONCERNS TODAY AND TONIGHT ACROSS OUR TERMINAL LOCATIONS. MVFR CEILINGS ARE THE PREVAILING CATEGORY THIS MORNING AS MOISTURE CONTINUES TO STREAM NORTHWARD WITH THE AID OF 50+ KTS AT 3KFT PER KSHV VWP DATA. ISENTROPIC LIFT IS RESULTING IN SOME DRIZZLE AND/OR LIGHT RAIN IN THE VCNTY OF THE ELD/SHV AND LFK TERMINALS. MEANWHILE...SCATTERED CONVECTION IS BEGINNING TO DEVELOP JUST SOUTH OF A WARM FRONT ACROSS PORTIONS OF NE TX/SE OK AND SW AR IN THE VCNTY OF THE TXK/ELD TERMINALS. HAVE TIMED FRONTAL PASSAGE ACCORDING TO THE LATEST HRRR DATA WHICH SHOWS THE FRONT INTO THE TXK/TYR TERMINALS BY 18Z...INTO THE SHV/ELD TERMINALS BY 21Z AND INTO THE LFK/MLU TERMINALS NEAR THE 00Z HOUR. WINDS AHEAD OF THIS FRONT WILL REMAIN STRONG WITH SUSTAINED WINDS NEAR 15KTS WITH HIGHER GUSTS. GRADIENT ACTUALLY APPEARS TO RELAX SLIGHTLY JUST AHEAD OF FRONTAL PASSAGE. WARM SECTOR WILL BECOME UNSTABLE TODAY AHEAD OF THE FRONTAL BOUNDARY AND WITH FRONTAL FORCING...EXPECT TO SEE A LINEAR LINE OF THUNDERSTORMS DEVELOPING ALONG THE FRONT ITSELF. EXPECT THE POSSIBILITY OF IFR CEILINGS BEHIND THE FRONTAL BOUNDARY LATE TODAY INTO TONIGHT WITH SOME POST FRONTAL CONVECTION AS WELL GIVEN THE FACT THAT THE 850MB FRONT IS MUCH SLOWER TO MOVE INTO THE REGION TONIGHT. 13 && .PREV DISCUSSION... /ISSUED 447 AM CST SAT FEB 21 2015/ DISCUSSION... NWD MOVG WARM FRONTAL BOUNDARY HAS STALLED OUT FOR TIME BEING...OVER EXTREME NORTHERN TIER OF CWA. COLD AIRMASS EXTREMELY SHALLOW...AS SEEN BY WILD TEMP FLUCTUATIONS WITHIN THE VALLEYS AND RIDGES OF THE OUACHITA MTNS. STG LOW LVL JET OF 50+ KNOTS FROM SW HAS ALLOWED LAKE WIND ADVISORY CRITERIA TO MAINTAIN ACROSS WESTERN CWA OVERNIGHT. WITH SFC TEMPS WARMING TO LOWER TO MID 70S...AND DEWPOINTS TO CONTINUE TO RISE INTO 60S IN WARM SECTOR...EXPECT TSTMS SOUTH OF I-30 TO POSSIBLY BECOME STG AS SOME DIURNAL HTG TO OCCUR BEFORE COLD FRONTAL PASSAGE. THIS FRONT WILL REACH THE I-20 CORRIDOR BY LATE IN AFTN...AND CONVECTION TO TRANSITION TO COLD RAIN WITH FROPA. CLOUDY SKIES AND CAA ON SUNDAY WILL PREVENT MUCH WARMING FROM OCCURRING WITH SAT NIGHT LOWS FALLING MOSTLY INTO UPPER 30S AND LOWER 40S. APPEARS ENOUGH MOISTURE LEFT WITH POST FRONTAL SHORT WAVE ARRIVING SUNDAY NIGHT FOR RAIN TO TRANSITION TO FRZG RAIN IN FALLING TEMPS AND VERY SHALLOW COLD AIRMASS MENTIONED EARLIER. SECOND SHORT WAVE ARRIVING TUESDAY APPEARS TO CONTAIN ENOUGH MOISTURE FOR PRECIP TO CONTINUE. WITH WARM NOSE AND SFC BASED INVERSION WEAKENING BY THEN...BETTER POTENTIAL FOR SNOW AND SLEET...AND SLEET WILL WORK ITS WAY DOWN THRU MOST OF CWA. GFS IS OBVIOUSLY TOO COLD...KEEPING DAYTIME TEMPS IN 20S MOST OF AREA SO LEANING CLOSER TO NAM. DEEPENING UPPER TROUGH TO WEST IN EXTENDED WILL YIELD MORE PRECIP LATER IN WEEK...WHICH MAY WELL ALSO BECOME A WINTRY MIX AS ARCTIC AIRMASS WILL REMAIN ENTRENCHED OVER THE AREA. /VII/. && .PRELIMINARY POINT TEMPS/POPS... SHV 72 42 47 30 34 / 60 40 30 50 60 MLU 74 41 49 29 34 / 60 60 30 50 60 DEQ 66 37 41 24 31 / 40 10 30 50 60 TXK 67 38 43 27 31 / 70 20 30 50 60 ELD 70 37 44 25 31 / 60 40 30 50 60 TYR 71 44 45 31 34 / 50 40 40 50 70 GGG 72 43 46 30 34 / 50 40 40 50 70 LFK 74 50 54 35 37 / 50 40 40 40 70 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...LAKE WIND ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING ZONES: ARZ070-071. LA...LAKE WIND ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING ZONES: LAZ001-002-010-017. OK...NONE. TX...LAKE WIND ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING ZONES: TXZ096-097-108>112-124>126-136>138-149>153-165>167. && $$ VII/13
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
942 PM EST SUN FEB 22 2015 .SYNOPSIS... A FRONTAL BOUNDARY STALLS ACROSS THE CAROLINA COAST TONIGHT AND MONDAY AS A WEAK AREA OF LOW PRESSURE MOVES EAST ALONG IT. AN ARCTIC COLD FRONT WILL PUSH ACROSS THE AREA MONDAY MORNING. HIGH PRESSURE RETURNS THROUGH MID WEEK. && .NEAR TERM /THROUGH MONDAY/... LOCALLY DENSE FOG HAS FORMED FM PORTIONS OF THE ERN SHORE TO CSTL SECTIONS IN SE VA (AND OVR THE ADJACENT WTRS). HAVE COVERED THE FOG W/ A SPECIAL WEATHER STATEMENT ON LAND...AND DENSE FOG ADVISORY OVR THE WTRS (UNTIL ABT 09Z/23). OTRW...VRB CLDS ACRS THE AREA WILL TEMPS CONTG A SLOW DROP THROUGH THE 30S/40S. SOME DRIER AIR WILL BE SPREADING SLOWLY INTO THE RGN FM THE NW BY LT TNGT...SO THE FOG IS XPCD TO DISSIPATE. LO TEMPS MNLY 30 TO 35F. 18Z/22 GFS AND RUC SUGGEST A LITTLE BETTER CHC FOR A PD OF LGT PCPN OVR SRN VA/NE NC LT TNGT INTO MID/LT MRNG HRS MON. HAVE ADJUSTED POPS UP ACRS SRN/SE VA AND NE NC. ADDED 30-50% CHC SN N OF THE VA/NC BORDER TO ABT FVX-LFI/SRN PORTION OF ERN SHORE...W/ PSBL ACCUM LESS THAN 1 INCH. MIXED PTYPC PSBL ACRS NE NC...PTNTLLY BECOMING SN BEFORE ENDING LT MON MRNG/EARLY AFTN. ANY PCPN WILL BE ARRIVING W/ LO LVL CAA INCRSG AS NEXT CDFNT PUSHES THROUGH THE RGN. TEMPS ONLY RISE A FEW DEGREES FROM 12Z READINGS THEN REMAIN STEADY OR SLOWLY FALL BACK INTO THE 20S IN THE AFTRN AS THE NEXT ARCTIC HIGH PRESSURE BUILDS INTO THE REGION ON GUSTY N-NW WINDS. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... MSTLY CLR TO PT CLDY SKIES MONDAY NIGHT AS RIDGE AXIS BUILDS OVER THE FA. RECORD LOWS IN JEOPARDY AS WINDS WEST OF THE BAY DECOUPLE ALLOWING FOR GOOD RADIATIONAL COOLING. WIND CHILL VALUES ALONG THE COAST ARE EXPECTED TO REMAIN ABOVE ADVISORY CRITERIA. ONLY THING THAT MIGHT PREVENT THE RECORDS FROM FALLING IS SOME MID / HIGH LEVEL CLOUDS NOTED IN TSCTNS. LOWS 5-10 EASTERN SHORE...10-15 ELSEWHERE EXCEPT M-U TEENS SERN BEACH AREAS. SEE CLI SECTION BELOW FOR TUES RECORD TMPS. PT TO MSTLY SUNNY TUESDAY. COLD AS H85 TMPS ONLY SUPPORT HIGHS IN THE U20S-M30S. MODELS SHOW WEAK AREA OF LOW PRESSURE (TROF) OFF THE SERN COAST TUESDAY NIGHT. EXPECT THE SGNFCNT MOISTURE TO STAY ALONG OR EAST OF THE CAROLINA COAST. WENT WITH A BIT MORE CLOUD COVERAGE OVER THE EAST THUS PT TO MSTLY CLDY SKIES AS AN UPPER LEVEL TROF SWINGS ACROSS THE NERN STATES. NOT AS COLD AS SW WINDS HOLD LOWS IN THE 20S. THE LOW PULLS FURTHER EAST AND OFF THE COAST WED. MILDER UNDER PT TO MSTLY SUNNY SKIES. WEST WINDS ALLOW TMPS TO WARM BACK INTO THE 40S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... THE LONG TERM WILL BRING SUBTLE CHANGES TO THE WEATHER. WHILE BELOW NORMAL TEMPERATURES WILL CONTINUE...THE COLD WILL NOT BE AS BRUTAL AS THE PAST WEEK. A SPLIT FLOW PATTERN WILL BRING A MORE ACTIVE SOUTHERN STREAM WILL BRING LOW PRESSURE SYSTEMS PASSING TO THE SOUTH OF THE AREA BUT WIDESPREAD PRECIPITATION IS NOT EXPECTED. FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT MID WEEK...A LOW PRESSURE SYSTEM MOVES OFF THE SOUTHEAST COAST WEDNESDAY NIGHT. PCPN SHOULD GENERALLY BE TO THE SOUTH OF THE AREA. GUIDANCE HAS VARIOUS CHANCES FOR PCPN SATURDAY THROUGH SUNDAY WITH RAIN OR SNOW SATURDAY AND SATURDAY NIGHT AND RAIN SUNDAY. A COLD FRONT APPROACHES FROM THE WEST LATE IN THE WEEKEND. KEPT POPS AT 30 PERCENT DURING THE WEEKEND. HIGH TEMPERATURES IN THE UPR 20S TO 30S THURSDAY AND FRIDAY WARM TO THE UPR 40S AND 50S BY SUNDAY. LOWS WILL BE MAINLY IN THE 20S...WARMING TO THE MID 30S NEAR THE SE VA/NE NC COAST SUNDAY MORNING. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... COLD FRONT ALONG THE NC/VA BORDER AND NE FLOW BEHIND THE BNDRY HAS BROUGHT SOME DENSE FOG TO COASTAL AREAS. THIS HAS MOSTLY AFFECTED AREAS ALONG THE PENINSULA TO THE EASTERN SHORE. EXPECT THE FOG TO IMPROVE BY AROUND MIDNIGHT AS THE FRONT SHIFTS A LITTLE FARTHER SOUTH AND A LITTLE DRIER AIR MOVES IN. A LOW PRES SYSTEM WILL MOVE ALONG THE FRONT AND OUT OF MS/AL OVERNIGHT AND OFF THE NC COAST BY EARLY MORNING. THE LOW WILL BRING SOME WINTRY PCPN TO THE AREA FROM ABOUT SUNRISE TO THE EARLY AFTN. A MIX OF -RA/FZRA/-SN/PL WILL AFFECT THE TAF SITES DURING THE MORNING WITH MOSTLY MVFR/IFR CONDS PREVAILING INTO THE AFTN. THE BEST CHC FOR FZRA/PL WILL BE ALONG THE SOUTHERN BORDER OF VA AND OVER NC. OUTLOOK...BECOMING VFR DURING THE AFTN AND MAINLY DRY...COLD AND VFR WEATHER EXPECTED TUE AND WED. && .MARINE... HAVE DECIDED TO ISSUE A SCA FOR THE ENTIRE WTRS STARTING LATE TNGT AND LASTING THRU MON EVENG/MON NGT. THERE IS STILL POTENTIAL FOR GALE GUSTS DURING LATE MON MORNG/AFTN TIMEFRAME AT THE MOUTH OF THE BAY AND CSTL WTRS S OF CAPE CHARLES...DUE TO STRONGER PRESSURE GRADIENT IN THIS AREA. BUT...FOR NOW WENT WITH A STRONG SCA IN THESE ZNS...AND WILL LET MIDNGT SHIFT DECIDE WHETHER TO UPGRADE TO A GALE WARNG BASED ON NEWER GUIDANCE. BASED ON 12Z/22 GUIDANCE...COLD ADVECTION REMAINS DELAYED BEHIND FRONT...WHICH WAS PUSHING OFF THE CST LATE THIS AFTN. THIS MEANS NORTHERLY WIND SURGE WON`T BEGIN UNTIL LATE TNGT/EARLY MON MORNG. SURGE WILL CONTINUE THRU MON...BEFORE WINDS DIMINISH MON NGT. SEAS WILL BLD TO 5-9 FT AND WAVES WILL BLD TO 3-5 FT IN THE CHES BAY. HI PRES BLDS ACRS THE REGION MON NGT/TUE...THEN MOVES OFFSHR TUE AFTN/TUE NGT...AHEAD OF NEXT ARCTIC FRONT. THIS FRONT WILL CROSS THE AREA ON WED...FOLLOWED BY ANOTHER SURGE OF COLD AIR FOR THU AND FRI. && .TIDES/COASTAL FLOODING... CONTINUED THE LOW WATER ADSY FOR THE LOWER BAY AND CSTL WATERS THROUGH 7 PM. && .CLIMATE... NORFOLK`S LOW TEMPERATURE OF 9 DEGREES ON FEB 20 WAS THE COLDEST FOR SO LATE IN THE SEASON. THE MINUS 4 DEGREE READING AT SALISBURY ON FEB 21ST IS NOW THE ALL TIME LOW FOR THE MONTH OF FEBRUARY. THE CURRENT AVERAGE TEMPERATURES FOR THE MONTH OF FEBRUARY AT BOTH RICHMOND AND NORFOLK PLACE THEM IN THE TOP 10 COLDEST. WITH ADDITIONAL COLD TEMPERATURES EXPECTED NEXT WEEK...IT IS VERY LIKELY THAT BOTH SITES WILL HAVE AVERAGE TEMPERATURES IN THE TOP 10 COLDEST FEBRUARYS ON RECORD...PERHAPS IN THE TOP 5 COLDEST. RECORD LOW TEMPERATURES FOR TUESDAY 2/24: RIC...11 IN 1914 ORF...16 IN 1947 SBY...10 IN 1934 ECG...19 IN 1947 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 7 PM EST MONDAY FOR ANZ635>638. DENSE FOG ADVISORY UNTIL 4 AM EST MONDAY FOR ANZ631-632-634- 638-650-652-654-656. SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO MIDNIGHT EST MONDAY NIGHT FOR ANZ630>634-650-652-654. SMALL CRAFT ADVISORY FROM 4 AM MONDAY TO 6 AM EST TUESDAY FOR ANZ656-658. && $$ SYNOPSIS...ALB/MPR NEAR TERM...ALB/MPR SHORT TERM...MPR LONG TERM...LSA AVIATION...JEF/LSA MARINE...LSA TIDES/COASTAL FLOODING... CLIMATE...
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
949 AM EST SAT FEB 21 2015 .SYNOPSIS... LOW PRESSURE WILL PASS THROUGH THE OHIO VALLEY LATE THIS AFTERNOON AND EVENING. THE COLD FRONT ASSOCIATED WITH THE LOW WILL PASS THROUGH THE AREA SUNDAY AND CANADIAN HIGH PRESSURE WILL BUILD OVERHEAD EARLY NEXT WEEK. A COLD FRONT WILL PASS THROUGH THE AREA WEDNESDAY AND HIGH PRESSURE WILL RETURN FOR LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SNOW WILL CONTINUE TO MOVE EASTWARD THIS MORNING IMPACTING THE BALTIMORE/WASHINGTON DC METROS BY NOON. REPORTS OF A HALF OF AN INCH TO AN INCH AN HOUR RATES HAVE BEEN REPORTED IN THIS INTIAL BAND MOVING ACROSS THE BLUE RIDGE MOUNTAINS THIS MORNING. A SHORTWAVE TROUGH HAS MOVED INTO THE NORTHERN OHIO VALLEY WHILE WARM AIR ADVECTION CONTINUES THIS MORNING. THE ENTIRE COLUMN ACROSS THE MID-ATLANTIC IS BELOW FREEZING AT THIS TIME AND THEREFORE SNOW IS EXPECTED ACROSS THE REGION. SNOW WILL CONTINUE TO MOVE FROM SW TO NE TODAY. MODERATE TO HEAVY SNOW IS EXPECTED THROUGH THE AFTERNOON. HIGH REFLECTIVITY BEING REPORTED ACROSS E KY AND W WV IS BELIEVED TO BE IN RESPONSE TO MELTING ALOFT. THE LATEST HRRR SHOWS THE HEAVIEST AXIS OF PRECIP TO BE LOCATED FROM THE VA HIGHLANDS/HIGHLAND COUNTY VA TO NOVA TO NE MD. WINTER WEATHER WARNINGS AND ADVISORIES ARE IN EFFECT AT THIS TIME. PLEASE SEE THE PRODUCTS FOR MORE INFORMATION REGARDING A SPECIFIC LOCAL. PREVIOUS DISCUSSION... DESPITE THE STRONG WARM ADVECTION...THERMAL PROFILES SUGGEST THAT THE AIRMASS WILL BE COLD ENOUGH FOR SNOW FOR MOST OF TODAY. HOWEVER...WARMER AIR WILL WORK ITS WAY IN ALOFT LATER THIS AFTERNOON AND EVENING...CAUSING PRECIPITATION TO CHANGE OVER TO A WINTRY MIX BEFORE FINALLY ENOUGH WARM AIR EVENTUALLY CAUSES PRECIPITATION TO CHANGE TO ALL RAIN. THERE IS STILL SOME UNCERTAINTY AS TO HOW MUCH SNOW WILL FALL TODAY BEFORE THE CHANGE OVER. HOWEVER...GIVEN THE STRONG FORCING AND ABUNDANT MOISTURE WITH THIS SYSTEM THE CURRENT FORECAST HAS LEANED TOWARD THE HIGHER SNOWFALL TOTALS...THINKING THAT MODERATE TO HEAVY SNOW CAN DEVELOP LATE THIS MORNING AND AFTERNOON BEFORE THE CHANGEOVER OCCURS. A WINTER STORM WARNING IS IN EFFECT FOR BALTIMORE...THE NORTHERN AND WESTERN SUBURBS OF WASHINGTON...AND FOR LOCATIONS ALONG AND WEST OF THE BLUE RIDGE MOUNTAINS. A WINTER WEATHER ADVISORY IS IN EFFECT FOR THE REST OF THE CWA. HAZARDOUS TRAVEL IS EXPECTED ACROSS THE ENTIRE AREA WITH THE WORST CONDITIONS EXPECTED LATE THIS MORNING THROUGH THIS EVENING. ALSO...KEEP IN MIND THAT EVEN WHEN TEMPERATURES RISE ABOVE FREEZING TONIGHT...PAVEMENT TEMPS MAY BE SLOWER TO RESPOND DUE TO THE RECENT COLD CONDITIONS. THE DRY SLOT WILL WORK ITS WAY INTO THE AREA LATE TONIGHT AND THIS MAY END PRECIPITATION ACROSS NORTHERN MARYLAND...NORTHERN VIRGINIA AND EASTERN WEST VIRGINIA. HOWEVER...TEMPS MAY HOVER CLOSE TO FREEZING ACROSS THESE AREAS. FARTHER SOUTHEAST TOWARD SOUTHERN MARYLAND AND THE VIRGINIA PIEDMONT...RAIN WILL CONTINUE ALL NIGHT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... THE DRY SLOT WILL CONTINUE TO OVERSPREAD MOST OF THE AREA SUNDAY...CAUSING PRECIPITATION TO END. HOWEVER...RAIN WILL CONTINUE ACROSS SOUTHERN MARYLAND INTO THE VIRGINIA PIEDMONT THROUGH MIDDAY BEFORE EVENTUALLY TAPERING OFF. LOW CLOUDS AND AREAS OF FOG EARLY SUNDAY SHOULD BURN OFF DURING THE DAY AS DRIER AIR WORKS ITS WAY INTO THE REGION. MAX TEMPS WILL RANGE FROM THE MID TO UPPER 30S IN NORTHERN MARYLAND...TO THE MIDDLE 40S IN CENTRAL VIRGINIA. THE COLD FRONT ASSOCIATED WITH THE LOW WILL PASS THROUGH OUR AREA SUNDAY AFTERNOON. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... REGION REMAINS POSITIONED UNDER UPPER LEVEL TROUGH THROUGH THE COMING WEEK. LOW PRESSURE EXITS BY 00Z MONDAY AS STRONG CANADIAN HIGH BUILDS SOUTH INTO THE CENTRAL PLAINS BY MONDAY MORNING. MID ATLANTIC WILL REMAIN ON THE EASTERN PERIPHERY OF THE HIGH AS IT SINKS TO THE SOUTH AND EVENTUALLY TURNS EAST OVER THE SOUTHEASTERN US AHEAD OF THE NEXT APPROACHING LOW PRESSURE SYSTEM. AS SUCH...FOR MONDAY AND TUESDAY HAVE DRY CONDITIONS IN PLACE. CAA PUSHES 850MB TEMPS DOWN TO AROUND 15 BELOW ZERO CELSIUS...KEEP TEMPS WELL BELOW NORMAL. DESPITE CLEARING SKIES...WILL SEE TEMPS ONLY RISE A COUPLE OF DEGREES DURING THE DAY MONDAY. LOWS TEMPS MONDAY NIGHT COULD SEE SOME AREAS ACROSS THE WESTERN CWA DROPPING BELOW ZERO...AND SINGLE DIGITS ABV ZERO FOR MOST OF THE REMAINING AREA. EXPECTING THE PRESSURE GRADIENT BETWEEN THE HIGH AND THE DEPARTING LOW TO HAVE SLACKEN BY MON NIGHT...ALONG WITH THE CAA WEAKENING. AS SUCH...WINDS WILL BE ON THE LIGHTER END...THOUGH COULD STILL SEE WIND CHILLS INTO THE TEENS BELOW ZERO FOR THE ALLEGHENY FRONT...WITH OTHER PORTIONS OF THE SHENANDOAH VALLEY REACHING SINGLE DIGITS BELOW ZERO. CLOSED LOW ALOFT PIVOTS INTO SOUTHEASTERN CANADA BY TUESDAY NIGHT...WITH ACCOMPANYING SFC LOW SWINGING INTO THE GREAT LAKES AND INTO THE NORTHEAST LATE TUES THROUGH WED. COLD FRONT SWINGS THROUGH THE MID ATLANTIC DURING THIS PERIOD...THOUGH SOME QUESTION AS TO THE EXTENT OF THE PCPN TOTALS. 00Z GFS A BIT FURTHER SOUTH WITH SHORTWAVE ENERGY...WHILE THE ECMWF HAS A MORE PRONOUNCED SOUTHERN STREAM WAVE THAT PUSHES KEEPS THE NORTHERN STREAM NORTH OF THE MASON-DIXON. WILL HOLD WITH SLIGHT CHC POPS FOR NOW DUE TO THE DIVERGENCE IN SOLUTIONS....EXCEPT WESTERN ALLEGHENY WHICH CAN EXPECT UPSLOPING SHOWERS IN THE WAKE OF THE COLD FRONT. TEMPS COLD ENOUGH THAT ANY PCPN THAT OCCURS WILL BE SNOW. SFC HIGH BUILDS IN ONCE AGAIN BEHIND THE COLD FRONT...BRINGING YET ANOTHER CANADIAN COLD AIRMASS...BUT DRY CONDITIONS THROUGH FRIDAY. WIND CHILLS COULD BECOME AN ISSUE YET AGAIN...MAINLY OVER WESTERN AREAS...WITH LOWS HOVERING RIGHT AROUND ZERO WED-THURS NIGHTS. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... SNOW WILL OVERSPREAD THE TERMINALS THIS MORNING FROM SOUTHWEST TO NORTHEAST. IFR/SUB-IFR CIGS AND VSBYS ARE EXPECTED ONCE SNOW BEGINS THROUGH THIS AFTERNOON. SNOW WILL CHANGE TO A WINTRY MIX LATE THIS AFTERNOON AND EVENING BEFORE ENDING AS SOME RAIN TONIGHT. HOWEVER...FREEZING RAIN MAY HANG ON FOR THE NORTHERN TERMINALS. IFR/SUB-IFR CONDITIONS WILL CONTINUE. PRECIPITATION WILL END LATE TONIGHT INTO SUNDAY FROM NORTHWEST TO SOUTHEAST AS DRIER AIR WORKS ITS WAY IN ALOFT. HOWEVER...LOW CLOUDS AND AREAS OF FOG WILL REDUCE CIGS/VSBYS THROUGH SUNDAY MORNING BEFORE CONDITIONS IMPROVE SUNDAY AFTERNOON. MAINLY VFR CONDITIONS THROUGH THE COMING WEEK WITH MULTIPLE PERIODS OF HIGH PRESSURE. SUB-VFR CONDITIONS POSSIBLE WITH ANY SNOW TUES NIGHT-WED. NW GUSTS TO 20 KTS PSBL SUN NIGHT-MONDAY...AND THEN AGAIN WEDNESDAY BEHIND THE FRONT. && .MARINE... A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS TODAY...AND PORTIONS OF THE MARYLAND CHESAPEAKE BAY AND LOWER TIDAL POTOMAC RIVER TONIGHT. A COLD FRONT WILL PASS THROUGH THE WATERS SUNDAY. WINDS WILL SHIFT TO THE NORTHWEST...BUT SPEEDS WILL LIKELY BE BELOW SCA CRITERIA SINCE THE PRESSURE GRADIENT WILL BE WEAK. TIGHTENING PRESSURE GRADIENT AND CAA WILL INCREASE WINDS SUNDAY NIGHT...WITH GUSTS 20-25 KTS. OCCASIONAL GUSTS TO 30 KTS PSBL MONDAY MORNING...WITH LOW CONFIDENCE OF GALES BEING REACHED. THE SCA CONDITIONS WILL CONTINUE THROUGH MONDAY...WITH WINDS GRADUALLY DIMINISHING MONDAY NIGHT. SUB-SCA CONDITIONS TUES-TUES NIGHT. PSBL SCA CONDITIONS RETURN BEHIND THE NEXT COLD FRONT WED WITH GUSTS UP TO 20 KTS LASTING INTO THURS. SUB-SCA CONDITIONS RETURN BY FRIDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR DCZ001. MD...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ003-501-502. WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR MDZ013-014. WINTER STORM WARNING UNTIL 9 AM EST SUNDAY FOR MDZ004>006-011- 503>508. WINTER WEATHER ADVISORY UNTIL 3 AM EST SUNDAY FOR MDZ016>018. VA...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR VAZ025>031-040- 501-503-504-506>508. WINTER WEATHER ADVISORY UNTIL 6 AM EST SUNDAY FOR VAZ036>039- 050>054-502. WINTER STORM WARNING UNTIL 9 AM EST SUNDAY FOR VAZ505. WINTER WEATHER ADVISORY UNTIL 3 AM EST SUNDAY FOR VAZ055>057. WV...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ050>053-055- 501>506. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ532- 540. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ530- 531-535-536-538-539. SMALL CRAFT ADVISORY UNTIL 1 AM EST SUNDAY FOR ANZ533-534-537- 541>543. && $$ SYNOPSIS...BJL NEAR TERM...BJL/HAS SHORT TERM...BJL LONG TERM...SEARS AVIATION...BJL/SEARS MARINE...BJL/SEARS/HAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
653 PM EST SUN FEB 22 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 305 PM EST SUN FEB 22 2015 A VERY COLD UPPER TROUGH IS SLIDING EAST ACROSS THE UPPER GREAT LAKES REGION THIS AFTERNOON...WITH RAP ANALYZED 850MB TEMPS OF -29C OVER WESTERN LAKE SUPERIOR. THIS HAS LED TO AFTERNOON TEMPERATURES AROUND 25-30 DEGREES BELOW THE NORMAL HIGHS FOR THIS TIME OF YEAR WITH 2PM TEMPERATURES RANGING FROM -10 AT KCMX TO 7 AT KMNM. THE COLD AIR AND A FEW BREAKS IN THE ICE...OR AT LEAST AREAS OF THIN ICE...HAS CONTINUED TO LEAD TO VERY THIN BANDS OF LAKE EFFECT OFF LAKE SUPERIOR IN THE NORTHWEST WIND SNOW BELTS. WHILE THE BANDS HAVE BEEN THIN...OBS AND WEBCAMS HAVE SHOWN THAT THEY CONTINUE TO BE EFFICIENT AT REDUCING VISIBILITIES WITH ALL OF THE CLOUDY WELL BELOW THE DGZ. THOSE VERY LOCALIZED LOWER VISIBILITIES HAVE ALSO BEEN AIDED BY BLOWING SNOW FROM THE GUSTY NORTHWEST WINDS OF 15-30MPH. MEANWHILE...A SURFACE HIGH IS CURRENTLY LOCATED OVER THE EASTERN DAKOTAS AND AN ASSOCIATED SURFACE RIDGE IS NOSING INTO THE UPPER GREAT LAKES. THE HIGH WILL DROP SOUTHEAST INTO THE MID MISSISSIPPI VALLEY TONIGHT...WHICH WILL PUSH A RIDGE ACROSS THE UPPER GREAT LAKES REGION. THIS RIDGE WILL LEAD TO BACKING WINDS THROUGH THE NIGHT...BECOMING SOUTHWESTERLY LATE TONIGHT OVER THE WEST AND MONDAY MORNING OVER THE EAST. THESE BACKING WINDS...ALONG WITH INCREASING SUBSIDENCE...WILL DIMINISH THE LAKE EFFECT POTENTIAL FROM THE LIMITED HEATING FROM LAKE SUPERIOR. THUS...EXPECT SKIES TO BECOME MOSTLY CLEAR THIS EVENING OVER MUCH OF THE AREA AS THE DIURNAL CU DISSIPATE...WITH THE EASTERN U.P. HANGING ON THE LONGEST INTO THE OVERNIGHT HOURS. WHILE THE CLEAR SKIES WILL PROMOTE RADIATIONAL COOLING...THINKING THERE WILL BE ENOUGH MIXING FROM JUST ABOVE THE SURFACE AND THE REMAINING PRESSURE GRADIENT TO KEEP LOWS FROM GETTING AS COLD AS SEEN A FEW DAYS AGO ON THE CLEAR/CALM NIGHTS. BUT WITH THE COLD AIR IN PLACE AND LITTLE REBOUND IN TEMPS TODAY...HAVE LOWS IN THE TEENS AND TWENTIES BELOW ZERO FOR TONIGHT. WHEN COMBINED WITH THE EXPECTED WINDS OF 4-8MPH TONIGHT...WIND CHILL VALUES WILL REMAIN IN THE -25 TO -35 DEGREE RANGE THROUGH MONDAY MORNING. DO HAVE A FEW AREAS WHERE WIND CHILLS WILL BE IN WARNING CRITERIA (GENERALLY OVER IRON COUNTY)...BUT WITH WINDS IN THOSE AREAS ONLY AROUND 5MPH OVERNIGHT...DIDN/T FEEL THAT THE WINDS WERE CLOSE ENOUGH TO OUR 10MPH CRITERIA TO ISSUE THE WARNING. ALSO AM A LITTLE CONCERNED WITH WIND CHILLS REACHING WARNING CRITERIA OVER THE KEWEENAW PENINSULA...AS THEY HAVE BEEN BOUNCING BACK AND FORTH OVER THE -35 CRITERIA LATE THIS MORNING AND INTO THE AFTERNOON. THIS WILL LIKELY CONTINUE THROUGH MUCH OF THE NIGHT AS WINDS BACK AND THE TIGHTEST GRADIENT PIVOTS OVER THAT AREA. EITHER WAY...IT WILL BE VERY COLD ACROSS UPPER MICHIGAN TONIGHT INTO MONDAY MORNING. OVERALL...MONDAY LOOKS TO BE QUIET ACROSS THE AREA AS THE HIGH PRESSURE RIDGE DEPARTS. AFTER A SUNNY START TO THE DAY...MID-HIGH CLOUDS WILL STREAM OVER THE AREA THROUGH THE AFTERNOON AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA LATE MONDAY NIGHT. BUT WITH ABUNDANT DRY AIR BETWEEN 900-700MB...EXPECT THE PRECIPITATION TO STAY OFF TO THE WEST OF UPPER MICHIGAN THROUGH THE LATE AFTERNOON. WINDS WILL GET GUSTY OUT OF THE SOUTHWEST DURING THE AFTERNOON AND ESPECIALLY THE EVENING. THUS...ADDED PATCHY BLOWING SNOW TO SOME AREAS OVER THE WEST DURING THE LATE AFTERNOON. WILL SEE HIGHS REBOUND INTO THE SINGLE DIGITS AND A FEW LOWER TEENS ABOVE ZERO TOMORROW...BUT WITH THE INCREASING WINDS IN THE AFTERNOON IT WILL STILL FEEL VERY COLD. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 356 PM EST SUN FEB 22 2015 PATTERN OF HIGH AMPLITUDE UPR RIDGE OVER THE ERN PACIFIC/WRN NAMERICA AND DEEP TROF OVER CENTRAL AND ERN NAMERICA WL PERSIST THRU MUCH OF THE WEEK...RESULTING IN A CONTINUED NW FLOW ALOFT THAT WL BRING ARCTIC SURGES INTO THE UPPER LKS THRU MID WEEK. TOWARD THE END OF THE WEEK THOUGH...FALLING HGTS OVER THE W WL ALLOW FOR A MORE ZONAL FLOW AND SOME AIRMASS MODERATION. BUT WITH DRY HI PRES FCST TO BE DOMINATING...LOW TEMPS MAY STILL BE QUITE COLD DESPITE THE MORE SEASONABLE H85 AND DAYTIME TEMPS. MON NGT/TUE...SHRTWV AND ACCOMPANYING SFC LOW DESCENDING SE INTO FAR NW ONTARIO BY MON EVNG ARE FCST TO SLIDE JUST NE OF LK SUP DURING THIS TIME...WITH ATTENDANT COLD FROPA MOVING OVER UPR MI LATE MON NIGHT AND TUE MRNG. SOME LIGHT SN IN THE WAA/ISENTROPIC ASCENT PATTERN AHEAD OF THIS DISTURBANCE WL OVERSPREAD UPR MI FM THE NW ON MON NGT AND PERSIST INTO TUE MRNG BEFORE THE COLD FROPA. SINCE THE MSTR INFLOW WL BE RATHER UNIMPRESSIVE...WITH MIXING RATIOS OF 1-1.5 G/KG FCST ON 280K ISENTROPIC SFC...AND VERY DRY ANTECEDENT AIRMASS IN PLACE WHICH WL TAKE TIME TO MOISTEN...ACCOMPANYING SN ACCUMS SHOULD BE LIMITED TO NO MORE THAN 1 TO 2 INCHES FOR MOST OF CWA WITH MAYBE A FEW LOCATIONS SEEING 3-4 INCHES FAR EAST AND OVER TIP OF KEWEENAW...WHERE HIGHER POPS/QPF WL BE MAINTAINED CLOSER TO THE SHRTWV TRACK...LONGER DURATION OF ISENTROPIC ASCENT AND AREA OF STRONGER DEEP LAYER Q-VECT CONV. ALTHOUGH MODELS SNDGS INDICATE THE DGZ TO BE RATHER DEEP AND INTERSECTING MUCH OF THE ASSOCIATED UVV...STRONG WINDS THROUGH THE MUCH OF THE LAYER MIGHT BREAK UP THE DENDRITES TO A CERTAIN EXTENT. BUT AT SAME TIME...THE SMALLER FLAKES WOULD BE MORE EFFICIENT AT RESTRICTING VSBY WHILE BEING BLOWN ABOUT BY THE GUSTY VEERING WINDS OCCURRING UNDER THE TIGHT PRES GRADIENT AHEAD OF THE COLD FRONT. WITH H85 THERMAL RDG OVER UPR MI ON MON NGT AND THE GUSTY WINDS...EXPECT RELATIVELY HIGH MIN TEMPS. WSHFT TO THE NW FOLLOWING THE TUE MORNING COLD FROPA WL DRAG ANOTHER ARCTIC AIRMASS BACK INTO THE CWA IN THE AFTN...DROPPING H85 TEMPS TO -20C OR COLDER AGAIN BY 00Z WED AND ALLOWING FOR AT LEAST SCATTERED LES TO DEVELOP IN WHATEVER BREAKS THERE ARE IN LAKE SUPERIOR ICE COVER. TUE NGT INTO WED NIGHT...MEDIUM RANGE GUIDANCE FCSTS H85 TEMPS TO FALL AS LO AS -28C TO -30C AROUND 12Z WED IN COLD NNW FLOW AHEAD OF THE NEXT CANADIAN HIGH PRES BUILDING TOWARD THE NRN PLAINS. THERE MAY BE SOME LES OFF BREAKS IN THE EXTENSIVE ICE COVER...BUT THE BIGGEST STORY WL BE WIND CHILLS AT LEAST REACHING INTO ADVY CRITERIA TUE NIGHT INTO WED MORNING AS 950 MB WINDS ARE FCST AOA 30 KTS DURING THE DESTABILIZING PERIOD OF CAA THAT WL DROP MIN TEMPS BLO ZERO AGAIN. AFTER HIGHS POSSIBLY STRUGGLING TO REACH ABV ZERO OVER THE NW CWA ON WED...ANOTHER BITTER COLD NIGHT IS IN STORE FOR WED NIGHT WITH DOUBLE DIGIT BLO ZERO READINGS LIKELY OVER A GOOD PORTION OF THE CWA. THU INTO SUN...THE ARCTIC HI OVER SCENTRAL CANADA ON WED IS FCST TO DRIFT SLOWLY TO THE ESE REACHING THE NRN PLAINS ON THU...AND THE MID MS VALLEY AND LOWER GREAT LAKES/OH RIVER VALLEY ON FRI BEFORE REACHING THE MID-ATLANTIC STATES ON SAT UNDER A PATTERN OF SLOWLY RISING 5H HGTS IN THE GREAT LAKES DOWNSTREAM OF TROFFING OVER WRN NAMERICA. THE RESULT WL BE A PERIOD OF MAINLY DRY WX UNDER DOMINANT SFC HIGH PRES RIDGE. ALTHOUGH THERE MAY BE SOME LES MAINLY E OF MARQUETTE INTO THU WHILE THE LLVL FLOW IS STILL NW...BACKING WINDS TOWARD THE W AND THEN SW WL SHIFT ANY REMAINING LES OUT INTO LK SUP BY LATE THU NIGHT. H85 TEMPS ARE FCST TO MODERATE TO -15C TO -17C BY FRI/SAT...ALLOWING DAYTIME TEMPS TO WARM NEAR 20F UNDER A GOOD DEAL OF SUNSHINE. HOWEVER...STILL EXPECT VERY COLD OVERNIGHT TEMPS (BLO ZERO) AT LEAST THU NIGHT AND FRI NIGHT AS FCST PWAT IS LOWER THAN .10 INCH UNDER LIGHT WINDS. MORE CLDS AND LIGHT MAY ARRIVE SAT NIGHT INTO SUN IN ADVANCE OF THE NEXT APPROACHING LOW PRES TROF. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 652 PM EST SUN FEB 22 2015 A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3 TAF SITES THIS FCST PERIOD. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX THRU THIS EVNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP SUFFICIENTLY ICE COVERED TO PREVENT ANY LES OR EVEN MUCH IN THE WAY OF CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY ON MON AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG FM THE NW. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 305 PM EST SUN FEB 22 2015 HIGH PRESSURE IN THE DAKOTAS WILL MOVES INTO THE MID MISSISSIPPI VALLEY LATE TONIGHT AND MONDAY MORNING...WHILE SHIFTING A RIDGE ACROSS THE UPPER GREAT LAKES REGION. THIS WILL LEAD TO WEAKENING WINDS TONIGHT...BEFORE QUICKLY INCREASING OUT OF THE SOUTHWEST ON MONDAY AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO. THIS WILL LEAD TO SOUTHWESTERLY GALES OF 35-40KTS OVER PORTIONS OF LAKE SUPERIOR MONDAY AFTERNOON/EVENING AND HAVE ISSUED A GALE WARNING FOR MUCH OF WESTERN/CENTRAL LAKE SUPERIOR FOR LATE MONDAY AFTERNOON AND MONDAY NIGHT. THEN AS A COLD FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE MONDAY NIGHT INTO TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST. THERE MAY BE A FEW GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS BELOW 20KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ MONDAY FOR MIZ001>007-009>011-013-014-084-085. WIND CHILL ADVISORY UNTIL 11 AM CST MONDAY FOR MIZ012. LAKE SUPERIOR... GALE WARNING FROM 7 PM MONDAY TO 7 AM EST TUESDAY FOR LSZ266. GALE WARNING FROM 4 PM EST /3 PM CST/ MONDAY TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...VOSS AVIATION...KC MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1224 AM EST SAT FEB 21 2015 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 333 PM EST FRI FEB 20 2015 AN APPROACHING ARCTIC COLD FRONT WILL SPREAD MOSTLY LIGHT SNOW ACROSS THE AREA THIS AFTERNOON AND TONIGHT. LOCALIZED HEAVIER SNOW IS EXPECTED AT THE LAKESHORE NORTH OF THE MUSKEGON AREA. THE SNOW WILL LINGER SATURDAY AS ANOTHER LOW MOVES NORTHEAST ACROSS THE OHIO VALLEY. LOCATIONS AROUND AND SOUTH OF I-94 COULD SEE UP TO A COUPLE INCHES OF ADDITIONAL SNOW SATURDAY. ANOTHER CLIPPER LOW COULD BRING SNOWY AND WINDY CONDITIONS ACROSS THE AREA TUESDAY COULD IMPACT TRAVEL. OTHERWISE...LAKE EFFECT SNOW SHOWERS WILL BE VERY COMMON THROUGH THE COMING WEEK. THERE WILL BE A VERY BRIEF WARMUP WITH HIGH TEMPERATURES APPROACHING 30 ON SATURDAY. THEN COLD RETURNS IN FORCE SATURDAY NIGHT WITH HIGHS GENERALLY IN THE TEENS AND LOWS IN THE SINGLE DIGITS OR BELOW ZERO FOR THE REST OF THE COMING WORK WEEK. && .UPDATE... ISSUED AT 915 PM EST FRI FEB 20 2015 WE`LL KEEP THE HEADLINE AS IS. IF WE`RE GOING TO GET ACCUMULATING SNOW...IT WILL BE ROUGHLY NOW THROUGH 09Z. WINDS ARE GRADUALLY BECOMING SOUTHWESTERLY AND WILL HELP TO PUSH THE LAKE COVERGENT BAND INLAND. LUDINGTON IS AT 1SM SN CURRENTLY AND UPSTREAM ECHOS SUGGEST VSBYS COULD FALL BELOW 1SM. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 333 PM EST FRI FEB 20 2015 INCREASED FORECAST SNOW AMOUNTS TONIGHT ALONG THE LAKESHORE NORTH OF WHITEHALL AND HOISTED AN ADVISORY. LUDINGTON VISIBILITIES ALREADY HAVE BEEN AT OR BELOW HALF A MILE IN SNOW AND WE EXPECT THAT AREA COULD EASILY SEE 5 INCHES OR MORE TOTAL ACCUMULATIONS OVERNIGHT. CURRENT SURFACE OBSERVATIONS SHOW A SIGNIFICANT OFFSHORE COMPONENT TO THE WINDS OVER OUR NORTHERN LAKESHORE AREA. HRRR GUIDANCE INDICATES A STRENGTHENING CONVERGENCE ZONE PARALLEL TO AND BARELY OFF THE LAKESHORE EARLY TONIGHT THAT SHOULD FOCUS BRIEFLY INTENSE SNOWFALL RATES. THIS CONVERGENCE AREA AND ASSOCIATED SNOWFALL SHOULD PUSH INLAND BY AROUND MIDNIGHT. ALTHOUGH THE ADVISORY IS SET TO EXPIRE AT 7 AM SATURDAY...COULD EASILY SEE SNOWFALL RATES DECREASING SIGNIFICANTLY AFTER MIDNIGHT. WITH THIS UPPER TROUGH IS A DEVELOPING SURFACE LOW THAT TRACKS NORTHEAST ACROSS THE OHIO VALLEY. WE ARE FAIRLY CERTAIN THAT IMPACTS WITH THIS SHOULD BE MINIMAL WITH PERHAPS A COUPLE INCHES ACCUMULATION NEAR JACKSON DURING THE DAY SATURDAY. SATURDAY NIGHT AND SUNDAY SHOULD SEE PERSISTENT LAKE EFFECT WITH 850 MB TEMPERATURES DROPPING TOWARDS -25C. LIMITED MOISTURE AND SUB-OPTIMAL MICROPHYSICS SHOULD LIMIT ADDITIONAL ACCUMULATIONS TO AROUND A COUPLE INCHES NEAR THE LAKESHORE. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 333 PM EST FRI FEB 20 2015 NO SIGNIFICANT CHANGES TO LONG TERM FORECAST...STRONG CLIPPER COULD BRING 35MPH+ WIND GUSTS ON TUESDAY WITH SNOW SQUALLS TUESDAY NIGHT INTO WEDNESDAY. ANOTHER ARCTIC AIRMASS WILL KEEP TEMPERATURES WELL BELOW NORMAL FOR THE END OF THE WEEK. LATEST 12Z GUIDANCE REMAINS IN VERY GOOD AGREEMENT ON EVOLUTION OF WEATHER PATTERN OVER THE NEXT WEEK. BASICALLY A CONTINUATION OF THE CURRENT WEATHER WITH THE ANOMALOUS WEST COAST RIDGE AND DOWN STREAM TROUGH CENTERED OVER GREAT LAKES. THERE IS HOWEVER SOME CHANCE OF A TEMPORARY BREAKDOWN OF THIS PATTERN NEXT WEEKEND WHICH WOULD LEAD TO NEAR NORMAL TEMPERATURES FOR THE END OF FEBRUARY. OUR EVENTUAL MID-WEEK CLIPPER IS PRESENTLY NORTH OF BARROW...ALASKA. IT IS FORECAST TO DIG SOUTHEASTWARD THROUGH WESTERN CANADA REACHING THE UPPER GREAT LAKES ON TUESDAY WITH AN ALMOST CLOSED H500 LOW BY WEDNESDAY. ALONG WITH IT COMES A SHOT OF SIBERIAN ARCTIC AIR. THIS WOULD NORMALLY BE A GOOD SETUP FOR A SIGNIFICANT LAKE ENHANCED EVENT...BUT HAVE A COUPLE OF CONCERNS. THE FIRST IS THE THAT THE WAVE IS PRESENTLY IN A DATA SPARSE AREA OBSERVATION WISE...SO WHILE THE TREND HAS BEEN STABLE AT PRESENT...WOULD NOT BE SURPRISED BY A JUMP OR TWO IN THE FORECAST OVER THE NEXT COUPLE OF DAYS. SECONDLY...LAKE MICHIGAN IS REALLY STARTING TO SLUSH UP AND THAT WILL BEGIN TO LIMIT THE ABILITY OF THE LAKE TO ENHANCE THE SYSTEM SNOWFALL. STAY TUNED... && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1223 AM EST SAT FEB 21 2015 MVFR CONDITIONS LOOK TO BE THE PREDOMINANT CATEGORY THE NEXT 24 HOURS...THROUGH 06Z SATURDAY NIGHT. THE MVFR CONDITIONS WILL MAINLY BE FROM CEILINGS IN THE 1000-3000FT RANGE THAT ARE FORECAST TO REMAIN IN PLACE. AN AREA OF LIGHT SNOW IS ALREADY EXITING THE AREA INTO EASTERN LOWER MICHIGAN AT 05Z...WITH SOME LIGHT SNOW LEFT OVER STILL NEAR THE LAKE MICHIGAN SHORE. THIS TOO SHOULD GRADUALLY WIND DOWN OVERNIGHT. KMKG HAS NOT BEEN IMPACTED MUCH AND NOT EXPECTING MUCH GOING FORWARD EITHER. ONLY REAL SNOW POTENTIAL...AND ITS VERY LOW CONFIDENCE/LOW POTENTIAL...IS DURING THE DAY ON SATURDAY. THE NORTHERN FRINGES OF THE PRECIPITATION SHIELD BRUSH THE AREA FROM THE OHIO VALLEY SYSTEM. HAVE LIGHT SNOW IN AT KBTL AND KJXN BUT NOT EXPECTING MUCH AT ALL. MOST MODELS HAVE THE SNOW MISSING THE AREA COMPLETELY. && .HYDROLOGY... ISSUED AT 308 PM EST FRI FEB 20 2015 FAIRLY STEADY RIVER LEVELS ARE EXPECTED ACROSS THE AREA... WITH NO SITES NEAR BANKFULL. TEMPERATURES WILL ONLY APPROACH FREEZING ON SATURDAY WITH VALUES BELOW 20 DEGREES MOST OF THE WEEK. THIS SHOULD RESULT IN THE ICE ON AREA RIVERS AND THE WATER IN THE SNOWPACK REMAINING LOCKED UP. CURRENTLY... THERE ARE NO SUSPECTED ICE JAMS IN THE AREA. SERIOUS ICE JAMS AND FLOODING CONCERNS ARE UNLIKELY UNTIL A SIGNIFICANT WARM UP AND RAINFALL OCCUR. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR MIZ037- 043-050. LM...NONE. && $$ UPDATE...04 SYNOPSIS...TJT SHORT TERM...TJT LONG TERM...COBB AVIATION...DUKE HYDROLOGY...63
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1200 AM EST SAT FEB 21 2015 .UPDATE... ISSUED AT 901 PM EST FRI FEB 20 2015 MOTHER NATURE HAD A FEW SURPRISES FOR US THIS EVENING. LAKE MI CONVERGENCE BAND SET UP WELL OFFSHORE OF MANISTEE/BENZIE COUNTIES...ONLY SLOWLY DRIFTING EAST. MBL AWOS HAS STRUGGLED TO REPORT ANY CLOUDS AT ALL...AND PRECIP THERE HAS BEEN MINIMAL. THE BAND TO THE WEST WILL ARRIVE IN THOSE AREAS TOWARD MIDNIGHT...BUT ONLY AS SYNOPTIC SUPPORT IS EXITING. BRIEF HEAVIER SNOW SHOWERS WILL RESULT...BUT WILL BE HARD TO GET MORE THAN 2 INCHES OR SO. SO THE ADVISORY HAS BEEN CANCELLED THERE. THIS BAND IS EDGING INTO FAR WESTERN MACKINAC CO. SOME REPORTS OF NEARLY 6 INCHES OF FLUFF WITH THIS ONE...A BIT NE OF ISQ IN SCHOOLCRAFT CO. HAVE BUMPED UP ACCUMS IN WESTERN MACK...BUT ONLY TO AROUND 3 INCHES...AS THE BANDS EASTWARD DRIFT IS INCREASING. N CENTRAL LOWER IS THE OTHER BULLSEYE...WITH A SMALL AREA OF 30DBZ RETURNS THAT STUCK BETWEEN THE OFFICE AND BELLAIRE FOR A BIT. THIS HAS STARTED TO WEAKEN AND PULL OUT TO THE ESE...BUT NOT BEFORE A QUICK BURST OF 2-3 INCHES. THIS AREA OF ENHANCED SNOW IS SOMEWHAT...INEXPLICABLE (CAN/T BLAME THE LAKES FOR THIS ONE)... BUT AS LONG AS IT DOESN/T REFORM IN THE SAME SPOT WE WILL MANAGE TO AVOID THE NEED FOR AN ADVISORY. STILL...HAVE BUMPED UP SNOWFALL TOTAL ACCUMS NEAR/E OF US-131 AND SOUTH OF M-32. && .NEAR TERM...(THIS EVENING THROUGH TONIGHT) ISSUED AT 406 PM EST FRI FEB 20 2015 ...WIDESPREAD GENERALLY LIGHT SNOW TONIGHT... HIGH IMPACT WEATHER POTENTIAL: NARROW CORRIDOR OF HEAVIER SNOW POSSIBLE WEST OF US-31 IN MANISTEE AND BENZIE COUNTIES AND OVER PARTS OF FAR WESTERN MACKINAC COUNTY...OTHERWISE GENERALLY LIGHT SNOW ACCUMULATIONS OVER THE REMAINDER OF THE AREA. PRIMARY FORECAST CHALLENGES/CONCERNS: HOW FAR INLAND WILL ENHANCED HEAVIER SNOW BAND OVER LAKE MICHIGAN GET INTO COASTAL AREAS. DETAILS: ISENTROPIC UPGLIDE /285-270K SFC/ INCREASING ACROSS NORTHERN MICHIGAN IN ADVANCE OF SHORTWAVE TROF OVER MN/NRN WI. TOP DOWN SATURATION GRADUALLY YIELDING LIGHT SNOW OVER FAR WESTERN PORTIONS OF THE AREA. LIGHT SNOW WILL OVERSPREAD THE ENTIRE AREA BY EARLY THIS EVENING...WITH A 6 HOUR WINDOW OF FAVORABLE DYNAMICS /ALBEIT SOMEWHAT LIMITED MOISTURE/. NOT THE MOST FAVORABLE CLOUD MICROPHYSICS WITH BEST OMEGA NOT SQUARELY FOCUSED WITHIN THE DGZ FOR MUCH OF THE SNOWFALL PERIOD. TRANSITORY NATURE OF THE SHORTWAVE COMBINED WITH MID LEVEL MIXING RATIO/S ON THE ORDER OF 1-2 G/KG POINT TOWARD A GENERAL 1-2 INCH SNOWFALL FOR MOST LOCATIONS. THE EXCEPTION TO THIS IS OVER PARTS OF MANISTEE...BENZIE AND MACKINAC COUNTIES...WHERE NORTH-SOUTH ORIENTED CONVERGENCE AREA UP THE SPINE OF LAKE MICHIGAN WILL CREATE POCKETS OF HEAVIER SNOW. HIGH RESOLUTION HRRR GUIDANCE SHOWS THIS ENHANCED LAKE MICHIGAN BAND QUITE WELL...KEEPING IT NEAR/ALONG THE LAKE MICHIGAN COAST THIS EVENING...POSSIBLY NOSING IT INTO FAR WESTERN MACKINAC COUNTY. AFTER COLLABORATION WITH THE GRAND RAPIDS NWS OFFICE AND WITH THE POTENTIAL FOR SOME LOCALIZED 3-5 INCH SNOWFALL AMOUNTS IN THE WESTERN PARTS OF BENZIE-MANISTEE COUNTIES...WENT AHEAD AND ISSUED A WINTER WEATHER ADVISORY THROUGH 7 AM SATURDAY. NO ADVISORY FOR MACKINAC COUNTY...AS BEST CONVERGENCE REMAINS SOUTH OF THAT AREA AND ENHANCED SNOWFALL POTENTIAL WOULD LIKELY ONLY IMPACT A SMALL PORTION OF THE COUNTY /FAR WESTERN AREAS/. WIDESPREAD SNOW ENDS FROM WEST-EAST AFTER MIDNIGHT AS THE SHORTWAVE PULLS EAST AND BEST DYNAMICS DIMINISH. A MUCH "WARMER" NIGHT IN STORE FOR THE AREA COMPARED TO LAST NIGHT /WHICH ISN`T EXACTLY SAYING MUCH/ WITH LOW TEMPERATURES GENERALLY IN THE SINGLE DIGITS ABOVE ZERO. && .SHORT TERM...(SATURDAY THROUGH MONDAY) ISSUED AT 406 PM EST FRI FEB 20 2015 HIGH IMPACT WEATHER POTENTIAL: ANOTHER COLD WAVE SUNDAY NIGHT/MONDAY MORNING, BUT NOT AS COLD AS THIS MORNING. FORECAST CHALLENGES: LES IMPACTS WITH MOST OF THE GREAT LAKES COVERED AND LOW TEMPERATURES AS THE NEXT COLD WAVE MOVE INTO THE UPPER GREAT LAKES SUNDAY/MONDAY. (2/21)SATURDAY...AROUND 12Z, THE COLD FRONT BEGINS TO MOVE THROUGH THE REGION. THE SOUTHWEST WINDS SHOULD BE TURNING WEST BY 12Z, LEADING TO A SHORT PERIOD OF WESTERLY FETCH FOR THE LAKE SNOW. THE ONLY ISSUE WITH ANY LES IS THE N LAKE MICHIGAN HAS LITTLE OPEN WATER, AND MOST OF THE THAT IS SOUTH OF THE MANITOU ISLANDS. WIND DIRECTIONS GIVE LIMITED FETCH AS THEY GET INTO N LOWER, AND EVEN E UPPER. SO HAVE SCALED BACK THE POPS A BIT AS THE OVERALL AREA WILL HAVE A LIGHT CLIPPER SNOW, WITH LITTLE ADDED LES ON THE BACK END. WINDS AFTER 18Z BECOME MORE NW AND NNW SO MAY GET SOME MINOR SNOW AND FLURRIES NORTH OF M-32 AS THE STREAM LINES POINT TO LITTLE TO NOTHING HAPPENING AS THE ATMOSPHERE DRIES OUT AS WELL BY THE EARLY EVENING. SATURDAY NIGHT...THE 850-700 MB LAYER RH FALL TO AROUND 40% BY 00Z AND WITH THE 850 MB TEMPERATURES OF -20C (AT 0Z)CROSSING THE ICE, THE LES WILL BE ALMOST NON-EXISTENT THROUGH MOST OF THE NIGHT. 850 MB TEMPERATURES CONTINUE TO COOL TO AROUND -30C IN LAKE SUPERIOR, PROVIDING SOME INSTABILITY, WITH THE MOISTURE AT 850-700 MB LAYER INCREASING TO AROUND 80% SOME LES WOULD BE POSSIBLE, BUT LACK OF OPEN WATER WILL BE DIFFICULT TO GET MUCH GOING. (2/22)SUNDAY...THE AIR MASS LOOKS COLD OVERNIGHT INTO SUNDAY MORNING, BUT THE MAIN PROBLEM IS THAT CLOUDS ARE EXPECTED TO MOVE INTO THE REGION BY 12Z, WHICH WILL PROBABLY INHIBIT THE TEMPERATURES FROM FALLING MUCH BELOW -20F. HOWEVER, CONSIDERING THE MODELS` ABILITY TO GET THE CLOUDS RIGHT, WOULD NOT BE SURPRISED IF THE LOW TEMPERATURES IN THE MORNING WILL BE COLDER THAN WE HAVE. THINK THAT THE LOWER TEENS BELOW ZERO IDEA IS THE BEST IDEA FOR NOW, UNTIL THE LIGHT SNOW GETS STARTED BY 18Z, MAYBE SOONER IF THE CLOUDS ENCROACH AND THE INSTABILITY CAN GET ENOUGH MOISTURE TO PRODUCE SNOW. MINOR SNOW ACCUMULATIONS ARE EXPECTED TO THROUGH 00Z. THE FLOW AND MOISTURE IS EXPECTED TO CONTINUE OVERNIGHT. (2/23)MONDAY...THE MORNING MAY TURN OUT DRY, BUT FOR NOW WILL CONTINUE THE LIGHT SNOW CHANCE, AS THE EXTREME COLD AIR AND RETREATING MOISTURE MAY PRODUCE MINOR ACCUMULATIONS. BY 18Z, THE WINDS TURN WSW, SO THAT THERE COULD BE SOME LES IN THE EVENING JUST BEFORE THE NEXT SYSTEM MOVES INTO THE UPPER GREAT LAKES. && .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 406 PM EST FRI FEB 20 2015 CONTINUED COLD WITH PERIODS OF SNOW. A COLD FRONT ASSOCIATED WITH A LOW PRESSURE SYSTEM NEAR JAMES BAY WILL EXTEND THROUGH MICHIGAN...POSSIBLY PRODUCING SOME ACCUMULATING SNOWS THROUGHOUT THE BEGINNING OF THE PERIOD AND MODERATING TEMPERATURES INTO THE 20S ON SOUTHERLY WINDS AHEAD OF THIS COLD FRONT. A LARGE AREA OF HIGH PRESSURE WILL BUILD IN BEHIND THIS DEPARTING SYSTEM AND DOMINATE THROUGH THE REMAINING PERIOD...CONTINUING THE COLD TEMPERATURES WHICH ARE FAR BELOW NORMAL FOR THIS TIME OF THE YEAR. WITH THE ABNORMALLY COLD TEMPERATURES WILL ALSO COME THE CHANCES OF NUISANCE LAKE CLOUDS AND SOME LAKE EFFECT SNOW SHOWERS WHERE OPEN WATERS STILL REMAIN OVER PORTIONS OF LAKE MICHIGAN AND LAKE SUPERIOR. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1200 PM EST FRI FEB 20 2015 REMAINING SYNOPTIC SNOW WILL GRADUALLY EXIT EASTWARD OUT OF NRN LWR MICHIGAN OVERNIGHT. HOWEVER...THIS SNOW WILL BE REPLACED WITH SCT/NMRS LAKE EFFECT SNOW SHOWERS AS LOW LEVEL WINDS SHIFT FROM THE SW TO THE WEST AND EVENTUALLY NW BY LATE SATURDAY AFTERNOON BEHIND ANOTHER WAVE RIDING THRU THE FAST 500 MB FLOW. THIS SECOND WAVE WILL ALSO PROVIDE SOME ENHANCED SYNOPTIC LIFT/MOISTURE TO ONGOING LAKE EFFECT SNOW SHOWERS SATURDAY AFTERNOON AND EVENING. OVERALL CONDITIONS WITHIN ANY SNOW WILL BE MAINLY MVFR...WITH CONDITIONS POSSIBLY LOWERING TO IFR WITHIN HEAVIER SNOW SHOWERS. SOUTHERLY SURFACE WINDS AROUND 10 KTS OVERNIGHT INTO SATURDAY WILL SHIFT TO THE NW UNDER 10 KTS BY LATE SATURDAY AFTERNOON. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...JAZ NEAR TERM...KEYSOR SHORT TERM...JSL LONG TERM...TJL AVIATION...MLR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
138 PM EST SAT FEB 21 2015 .SYNOPSIS... AN ELONGATED AREA OF LOW PRESSURE WILL CROSS THE GREAT LAKES BRINGING WIDESPREAD...MAINLY LIGHT...SNOWFALL TO THE REGION THROUGH THIS EVENING. AREAS OF FREEZING DRIZZLE WILL BE POSSIBLE IN THE WAKE OF THE SYSTEM LATER TONIGHT INTO SUNDAY BEFORE TEMPERATURES PLUNGE SUNDAY NIGHT AS ANOTHER ARCTIC FRONT SWEEPS ACROSS THE GREAT LAKES...BRINGING POTENTIALLY RECORD BREAKING COLD ALONG WITH LAKE EFFECT SNOW SHOWERS BY MONDAY. WHILE MONDAY WILL BE THE COLDEST DAY OF THE PERIOD...TEMPERATURES ARE EXPECTED TO REMAIN BELOW AVERAGE THROUGH NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AT 100 PM...RADAR SHOWS SNOW HAS OVERSPREAD THE REMAINDER OF THE REGION WITH THE STEADIEST SNOW BETWEEN ROCHESTER AND WATERTOWN. THIS IS PROBABLY ASSOCIATED WITH A SLUG OF WARM AIR ADVECTION WITH A SOUTHERLY 40 KT 925MB FLOW. THIS WILL CONTINUE TO LIFT NE THROUGH THIS AFTERNOON. BEHIND THIS...IS A LULL IN THE ACTION...WITH RADAR SHOWING ONLY LIGHT RETURNS. THIS LULL WILL ONLY LAST A COUPLE HOURS...WITH RADAR SHOWING A LINE OF STEADIER SNOW BEHIND THIS...EXTENDING FROM LAKE ERIE TO WESTERN LAKE ONTARIO. THE SOUTHWESTERLY MID-UPPER LEVEL FLOW WILL PUSH THIS AREA EAST ACROSS WESTERN NEW YORK LATE AFTERNOON AND INTO THIS EVENING. THIS WILL RESULT IN ANOTHER BURST OF SNOWFALL DURING THIS TIME. LATEST RUNS OF THE HRRR CAPTURE THIS WELL...WITH OTHER HIGH RESOLUTION GUIDANCE HINTING AT THIS BREAK TO A LESSER EXTENT. THERE ARE ALSO SOME MESOSCALE FEATURES IN PLAY. DOWNSLOPING HAS LIMITED SNOWFALL RATES IMMEDIATELY NE OF THE CHAUTAUQUA RIDGE...WITH A ENHANCED SNOWFALL RATES ACROSS THE NIAGARA FRONTIER NEAR LAKE ONTARIO. SINCE...THE STRONGER SOUTHERLY FLOW HAS SHIFTED EAST WITH THIS EXPECTED TO HAVE LITTLE IMPACT FOR THE REMAINDER OF THE AFTERNOON HOURS. HOWEVER...AS THE SOUTHERLY FLOW INCREASES ACROSS EASTERN PORTIONS OF THE CWA...MOST HIGH RESOLUTION GUIDANCE SHOWS SIGNIFICANT UPSLOPING ON THE SOUTH FACE OF THE TUG HILL. WHILE THIS IS SOMETIMES OVERDONE...IT APPEARS REASONABLE THIS TIME WITH A SATURATED BOUNDARY LAYER AND RADAR CURRENTLY SHOWING THIS ENHANCEMENT. THESE MESOSCALE FEATURES WILL HAVE AN IMPACT ON SNOW AMOUNTS. IN THE ADVISORY AREA...EXPECT MOST AREAS TO GET 2 TO 4 INCHES OF SNOW...WITH 1 TO 3 INCHES ACROSS THE GENESEE VALLEY. LOCALIZED AMOUNTS OF A BIT MORE ARE LIKELY IN NIAGARA COUNTY. THE GREATEST AMOUNTS WILL PROBABLY BE IN OSWEGO AND SOUTHERN LEWIS COUNTIES WHERE 4 TO 7 INCHES OF SNOW IS EXPECTED. SNOW WILL TAPER OFF FROM WEST TO EAST AS THE UPPER LEVEL JET AND DEEPER MOISTURE TRANSLATES TO THE EAST COAST. EVEN AS THE DEEPER MID-LEVEL MOISTURE IS STRIPPED OUT...WEAK ASCENT DUE TO APPROACHING MID/UPPER LEVEL TROUGHING ALONG WITH WESTERLY UPSLOPE FLOW MAY RESULT IN A TRANSITION FROM LINGERING SNOW SHOWERS TO AREAS OF FREEZING DRIZZLE LATER ON TONIGHT...PARTICULARLY ACROSS UPSLOPE AREAS OF WESTERN NEW YORK AND EVENTUALLY THE NORTH COUNTRY. IN ADDITION TO THE SNOW...A WINTER WEATHER ADVISORY IS IN PLACE FOR THIS POTENTIAL. FORECAST CONFIDENCE IN FREEZING DRIZZLE IS MARGINAL...WITH FORECAST SOUNDINGS SUPPORTING FREEZING DRIZZLE IF PRECIPITATION OCCURS...BUT STILL SOME UNCERTAINTY IF THE FLOW WILL BE STRONG ENOUGH TO GENERATE ANY PRECIPITATION. TEMPERATURES WILL RISE INTO THE 20S TODAY...WHICH WILL PROBABLY FEEL QUITE WARM TO MANY GIVEN THE COLD WEATHER OF LATE. EVEN AS THE ELONGATED TROUGH PASSES TO OUR EAST TONIGHT...THERE WILL BE ONLY MODEST COLD AIR ADVECTION WITH OVERNIGHT LOWS IN THE TEENS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... SUNDAY WILL START OFF WITH WITH BROAD CYCLONIC FLOW ALOFT AND A COLD AIR ADVECTION REGIME BEHIND THE DEPARTING SURFACE LOW. FORECAST SOUNDINGS INDICATE THAT MID-LEVEL DRY AIR WILL BE IN PLACE ACROSS WESTERN AND CENTRAL NEW YORK...WITH PLENTIFUL LOW-LEVEL MOISTURE IN THE WESTERLY FLOW. LOW-LEVEL TEMPERATURES ARE PROGGED TO BE IN THE -4 TO -10C RANGE AND SATURATED...WITH WITH DRY AIR IN PLACE IN THE MID-LEVEL...TYPICAL OF A FREEZING DRIZZLE SOUNDING. EXPECT AREAS OF FREEZING DRIZZLE WITH A CHANCE FOR SOME LIGHT SNOW/FLURRIES MIXED IN A TIMES....ESPECIALLY ALONG THE UPSLOPE AREAS OF THE WESTERN SOUTHERN TIER AND THE TUG HILL AREA. BY THE AFTERNOON...THE FREEZING DRIZZLE CHANCES SHOULD RAPIDLY COME TO AN END AS COLDER AIR CONTINUES TO ADVECT INTO THE AREA...PUSHING THE LOW-LEVEL TEMPERATURES INTO THE DENDRITIC GROWTH TEMPERATURE RANGE...ALLOWING FOR A CHANGE OVER TO SNOW ACROSS THE AREA. TEMPERATURES ON SUNDAY WILL BE FAIRLY STAGNANT IN THE LOW 20S THROUGH THE MORNING...THEN WILL START TO FALL THROUGH THE AFTERNOON AS THE TRUE ARCTIC SOURCED AIR FINALLY STARTS TO PUSH INTO WESTERN NEW YORK. THE BOTTOM WILL FALL OUT SUNDAY EVENING AS TEMPERATURES PLUNGE TOWARD ZERO BY MIDNIGHT AS THE CORE OF THE -24C TO -30C 850 MB AIR ARRIVES. ACCOMPANYING THE ARCTIC FRONT...WILL BE SOME INCREASED WINDS AS THE PRESSURE GRADIENT TIGHTENS BETWEEN AN IMPRESSIVE 1049MB HIGH OVER THE CENTRAL CONUS AND THE 999MB LOW OVER NEW BRUNSWICK. THE COMBINATION OF TEMPERATURES PLUNGING AND STEADY WINDS IN THE CAA ACROSS THE AREA WILL LIKELY PROMPT ANOTHER PERIOD OF BITTER WIND CHILLS THAT WILL EVENTUALLY NEED HEADLINES ONCE CONFIDENCE ON THE MAGNITUDE OF THE WIND CHILLS IMPROVES. LAKE EFFECT SNOW POTENTIAL OFF OF LAKE ONTARIO... ONCE THE ARCTIC AIR STARTS WORKING ACROSS THE LAKE SUNDAY AFTERNOON AND EVENING...LAKE EFFECT SNOWS WILL PICK UP ALONG THE SOUTHEAST SHORE. LAKE PARAMETERS SHOW THE EQUILIBRIUM LEVELS RISING TO 5-8KFT LATE SUNDAY...THEN PICKING UP OVERNIGHT TO 10KFT OR SO BY MONDAY MORNING...BEFORE THE CAPPING INVERSION QUICKLY LOWERS LATE MONDAY AFTERNOON WITH RISING HEIGHTS / SUBSIDENCE UNDER THE BUILDING RIDGE. THE MEAN NORTHWEST FLOW DURING THIS TIME PERIOD WILL CONCENTRATE THE HEAVIEST LAKE SNOWS FROM EASTERN NIAGARA COUNTY ACROSS TO SOUTHWEST OSWEGO COUNTY...SIMILAR TO THE MOST RECENT LAKE EFFECT EVENT. EXPECT THE HIGHEST SNOW ACCUMULATIONS WILL BE IMMEDIATELY ALONG THE LAKE SHORE...AND WILL TAPER OFF QUICKLY INLAND...DUE TO THE MULTIBANDED STRUCTURE AND THE REDUCED FETCH DUE SOME ICE COVER ON LAKE ONTARIO. SHOULD THESE LAKE PARAMETERS HOLD...ADVISORY HEADLINES MAY EVENTUALLY BE NEEDED MAINLY FOR LOCATIONS IMMEDIATELY ALONG THE LAKE SHORE. TEMPERATURES ON MONDAY... FORECAST CONFIDENCE IS HIGH IN ANOTHER ROUND OF POTENTIALLY RECORD SETTING COLD AIR FOR MONDAY. GLOBAL MODELS AND THEIR ENSEMBLES ARE IN EXCELLENT AGREEMENT ON A STRONG 500 MB LOW PASSING NORTH OF NEW YORK DURING THE DAY MONDAY. NAEFS PERCENTILES SHOW FORECAST 850 MB TEMPERATURES ONCE AGAIN REACH RECORD VALUES FOR THE 1979-2009 CLIMATE PERIOD. THIS WILL TRANSLATE TO LOW TEMPERATURES MONDAY MORNING AND AGAIN TUESDAY MORNING RANGING FROM AROUND 0 NEAR LAKE ONTARIO TO TEENS BELOW ZERO AWAY FROM THE LAKE. HIGH TEMPERATURES ON MONDAY WILL LIKELY REMAIN WITHIN A FEW DEGREES EITHER SIDE OF 0. && .LONG TERM /TUESDAY THROUGH FRIDAY/... WHILE TEMPERATURES DURING THIS PERIOD WILL NOT BE AS BRUTAL AS THEY HAVE BEEN IN RECENT DAYS...THE PRESENCE OF A DEEP LONGWAVE TROUGH OVER NORTH AMERICA WITH A CONTINUED FLOW OUT OF THE CANADIAN ARCTIC WILL KEEP OUR MERCURY AT BELOW NORMAL LEVELS. A MODERATING SOUTHWESTERLY FLOW BETWEEN HIGH PRESSURE TO OUR SOUTH AND LOW PRESSURE APPROACHING FROM THE NORTHWEST WILL BRING ANOTHER SLIGHT WARM-UP WITH HIGH TEMPS BUMPING THE 20 DEGREE MARK IN SOME SPOTS UPPER TEENS ELSEWHERE. THE LOW TO THE NORTHWEST WILL BRING ANOTHER ROUND OF SNOW TUESDAY EVENING THROUGH MUCH OF WEDNESDAY. THERE MAY BE A MODERATE TO BRIEFLY HEAVY SNOW WITH THE PASSAGE OF AN ARCTIC FRONT ACCOMPANYING THE LOW. OTHERWISE...SNOW SHOULD BE LIGHT IN NATURE AND NOT POSE MUCH MORE THAN A FEW INCHES OF ACCUMULATION. THE COLDER AIR FOLLOWING THE LOW WILL NOT BE NEARLY AS COLD AS IN RECENT EVENTS. 850MB TEMPS DO FALL TO ABOUT -24C OVER LAKE ONTARIO ON WEDNESDAY NIGHT AND THURSDAY...AND WITH A WELL ALIGNED WESTERLY WIND WILL PRODUCE A BAND OF LAKE EFFECT SNOW ALONG THE SOUTH SHORE INLAND TO CENTRAL NY. SPRAWLING HIGH PRESSURE CENTERED OVER THE UPPER PLAINS TO BREADBASKET PROVINCES WILL BUILD EASTWARD ACROSS THE REGION ON THURSDAY NIGHT AND FRIDAY. THIS WILL DRYING AND SUBSIDENCE TO THE AREA WITH AN END OF THE LAKE EFFECT AND MORE SUNSHINE...EVEN THE OPPORTUNITY FOR A WARMING TREND. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... THERE WILL BE TW0 BANDS OF LIGHT SNOW WHICH MOVE ACROSS THE REGION TODAY. THE FIRST EXTENDS FROM R0C-ART AT 18Z WITH THIS FORECAST TO CONTINUE TO LIFT TO THE NE THROUGH THIS AFTERNOON. BEHIND THIS WILL BE A BRIEF LULL IN SNOWFALL RATES...FOLLOWED BY ANOTHER BAND OF STEADIER SNOW LATE AFTERNOON AND INTO THIS EVENING. IN STEADIER SNOWS...EXPECT IFR OR LOWER CONDITIONS WITH VSBY AVERAGING AROUND 1SM. AFTER THIS...THE MID-LEVELS DRY OUT WITH A POTENTIAL FOR -FZDZ LATE TONIGHT AND INTO MONDAY. FORECAST CONFIDENCE IN THIS IS MARGINAL...WITH A CHANCE THAT PRECIPITATION WILL NOT MATERIALIZE. EXPECT IFR-MVFR CIGS THROUGH 12Z. AFTER THIS...INCREASING SW WINDS SHOULD HELP MIX LOW LEVEL MOISTURE...WITH LIFTING CIGS SUNDAY MORNING. OUTLOOK... SUNDAY NIGHT...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE. MONDAY...MVFR/IFR IN LAKE SNOW SOUTH OF LAKE ONTARIO. VFR ELSEWHERE. TUESDAY...VFR. WEDNESDAY AND THURSDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE. && .MARINE... RELATIVELY TRANQUIL CONDITIONS ON LAKE ONTARIO WILL PERSIST THROUGH TONIGHT AS A WEAK AREA OF LOW PRESSURE CROSSES THE REGION. FRESHENING WESTERLY FLOW WILL DEVELOP BEHIND THE PASSING LOW SUNDAY AFTERNOON. AN ARCTIC FRONT DROPPING ACROSS THE LAKES SUNDAY NIGHT WILL LIKELY BRING ANOTHER ROUND OF SMALL CRAFT ADVISORIES WITH BRISK WNW FLOW LASTING THROUGH MONDAY WITH WINDS BACKING TO THE SW TUESDAY AHEAD OF ANOTHER CLIPPER THAT IS EXPECTED TO PASS NORTH OF THE GREAT LAKES. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR NYZ001-002- 006>008-010>012-019>021-085. MARINE...NONE. && $$ SYNOPSIS...WOOD NEAR TERM...APFFEL SHORT TERM...CHURCH LONG TERM...CHURCH/WCH AVIATION...APFFEL MARINE...APFFEL/WOOD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1128 AM EST SAT FEB 21 2015 .SYNOPSIS... AN ELONGATED AREA OF LOW PRESSURE OVER THE CENTRAL UNITED STATES WILL CROSS THE GREAT LAKES TODAY BRINGING WIDESPREAD...MAINLY LIGHT...SNOWFALL TO WESTERN AND NORTH CENTRAL NEW YORK TODAY INTO TONIGHT ALONG WITH RELATIVELY WARMER TEMPERATURES IN THE 20S. AREAS OF FREEZING DRIZZLE WILL BE POSSIBLE IN THE WAKE OF THE SYSTEM LATER TONIGHT INTO SUNDAY BEFORE TEMPERATURES PLUNGE SUNDAY NIGHT AS ANOTHER ARCTIC FRONT SWEEPS ACROSS THE GREAT LAKES...BRINGING POTENTIALLY RECORD BREAKING COLD ALONG WITH LAKE EFFECT SNOW SHOWERS BY MONDAY. WHILE MONDAY WILL BE THE COLDEST DAY OF THE PERIOD...TEMPERATURES ARE EXPECTED TO REMAIN BELOW AVERAGE THROUGH NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AT 1100 AM...LIGHT SNOW HAS SPREAD ACROSS MUCH OF WESTERN NEW YORK...WITH LIGHT SNOW EXPECTED TO CONTINUE TO SPREAD ACROSS THE REMAINDER OF THE CWA BY EARLY AFTERNOON. SYNOPTIC SUPPORT STEMS FROM A BROAD AREA OF WARM AIR ADVECTION...WITH SOME MODEST UPPER LEVEL SUPPORT FROM A SHORTWAVE EMBEDDED IN A CYCLONIC FLOW. RADAR SHOWS SOME LOW LEVEL ENHANCEMENT FROM WESTERN LAKE ERIE...ACROSS SOUTHERN ONTARIO...AND INTO THE NIAGARA FRONTIER. THIS IS NOT UNCOMMON FOR THESE AREAS WHEN THERE IS A SOUTHERLY FLOW...WHICH DOWNSLOPES ACROSS THE CHAUTAUQUA RIDGE...BUT THEN ENHANCES LIFT IN THE AFOREMENTIONED REGIONS. HIGH RESOLUTION GUIDANCE CAPTURES THIS...WITH THIS ENHANCEMENT LIKELY CONTINUE THROUGH EARLY AFTERNOON WHEN WINDS DIMINISH AND SHIFT TO THE SSW. OTHERWISE...STEADIEST SNOWS SHOULD BE ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER THROUGH EARLY AFTERNOON WHERE THERE IS THE MOST MOISTURE AND SYNOPTIC SCALE LIFT. THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE TRENDS...BUT IS RUNNING ABOUT AN HOUR SLOW WITH ITS TIMING. DUE TO BOTH THE THREAT FOR FREEZING DRIZZLE LATE TONIGHT AND THE GENERAL LIGHT SNOW HAVE EXPANDED THE WINTER WEATHER ADVISORY FOR MUCH OF WESTERN NEW YORK. HAVE ALSO EXTENDED THE TIMING OF THE ADVISORY AND ADDED JEFFERSON COUNTY FOR THE EASTERN LAKE ONTARIO REGION. IN THESE AREAS ADDED...SNOW AMOUNTS WILL BE MARGINAL TO ADVISORY CRITERIA...BUT THERE SHOULD BE AT LEAST 2 OR 3 INCHES...WITH UP TO 5 INCHES IN NIAGARA COUNTY...AND IN CHAUTAUQUA/CATTARAUGUS COUNTIES. THERE WILL BE LESSER AMOUNTS OF SNOW AND A LESSER FREEZING DRIZZLE THREAT FOR THE GENESEE VALLEY...SO HAVE LEFT THESE AREAS OUT OF THE ADVISORY FOR NOW. EXPECT SNOWFALL TO BE ACCORDINGLY LIGHT WITH MOST AREAS SEEING A GENERAL 2 TO 4 INCHES THROUGH THIS EVENING. SOUTHERLY DOWNSLOPING IN THE VICINITY OF THE FINGER LAKES MAY RESULT IN ACCUMULATIONS ON THE LOWER END OF THESE VALUES WHILE SIMILAR UPSLOPING ONTO THE TUG HILL PLATEAU SHOULD YIELD SLIGHTLY HIGHER ACCUMULATIONS IN THE NEIGHBORHOOD OF 4 TO 7 INCHES THROUGH TONIGHT. SNOW WILL TAPER OFF FROM WEST TO EAST AS THE UPPER LEVEL JET AND DEEPER MOISTURE TRANSLATES TO THE EAST COAST. EVEN AS THE DEEPER MID-LEVEL MOISTURE IS STRIPPED OUT...WEAK ASCENT DUE TO APPROACHING MID/UPPER LEVEL TROUGHING ALONG WITH WESTERLY UPSLOPE FLOW MAY RESULT IN A TRANSITION FROM LINGERING SNOW SHOWERS TO AREAS OF FREEZING DRIZZLE LATER ON TONIGHT...PARTICULARLY ACROSS UPSLOPE AREAS OF WESTERN NEW YORK AND EVENTUALLY THE NORTH COUNTRY. REGARDING TEMPERATURES...AFOREMENTIONED WARM ADVECTION WILL CONTINUE TO PUSH TEMPERATURES UPWARDS THROUGH THE DAY TODAY WITH HIGHS CLIMBING INTO THE 20S BY THIS AFTERNOON. TEMPERATURES WILL CONTINUE TO CLIMB INTO THE UPPER 20S TONIGHT AS THE WARMEST AIR SURGES NORTH ACROSS THE REGION IN ADVANCE OF A SURFACE COLD FRONT THAT CROSSES THE REGION SUNDAY. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... SUNDAY WILL START OFF WITH WITH BROAD CYCLONIC FLOW ALOFT AND A COLD AIR ADVECTION REGIME BEHIND THE DEPARTING SURFACE LOW. FORECAST SOUNDINGS INDICATE THAT MID-LEVEL DRY AIR WILL BE IN PLACE ACROSS WESTERN AND CENTRAL NEW YORK...WITH PLENTIFUL LOW-LEVEL MOISTURE IN THE WESTERLY FLOW. LOW-LEVEL TEMPERATURES ARE PROGGED TO BE IN THE -4 TO -10C RANGE AND SATURATED...WITH WITH DRY AIR IN PLACE IN THE MID-LEVEL...TYPICAL OF A FREEZING DRIZZLE SOUNDING. EXPECT AREAS OF FREEZING DRIZZLE WITH A CHANCE FOR SOME LIGHT SNOW/FLURRIES MIXED IN A TIMES....ESPECIALLY ALONG THE UPSLOPE AREAS OF THE WESTERN SOUTHERN TIER AND THE TUG HILL AREA. BY THE AFTERNOON...THE FREEZING DRIZZLE CHANCES SHOULD RAPIDLY COME TO AN END AS COLDER AIR CONTINUES TO ADVECT INTO THE AREA...PUSHING THE LOW-LEVEL TEMPERATURES INTO THE DENDRITIC GROWTH TEMPERATURE RANGE...ALLOWING FOR A CHANGE OVER TO SNOW ACROSS THE AREA. TEMPERATURES ON SUNDAY WILL BE FAIRLY STAGNANT IN THE LOW 20S THROUGH THE MORNING...THEN WILL START TO FALL THROUGH THE AFTERNOON AS THE TRUE ARCTIC SOURCED AIR FINALLY STARTS TO PUSH INTO WESTERN NEW YORK. THE BOTTOM WILL FALL OUT SUNDAY EVENING AS TEMPERATURES PLUNGE TOWARD ZERO BY MIDNIGHT AS THE CORE OF THE -24C TO -30C 850 MB AIR ARRIVES. ACCOMPANYING THE ARCTIC FRONT...WILL BE SOME INCREASED WINDS AS THE PRESSURE GRADIENT TIGHTENS BETWEEN AN IMPRESSIVE 1049MB HIGH OVER THE CENTRAL CONUS AND THE 999MB LOW OVER NEW BRUNSWICK. THE COMBINATION OF TEMPERATURES PLUNGING AND STEADY WINDS IN THE CAA ACROSS THE AREA WILL LIKELY PROMPT ANOTHER PERIOD OF BITTER WIND CHILLS THAT WILL EVENTUALLY NEED HEADLINES ONCE CONFIDENCE ON THE MAGNITUDE OF THE WIND CHILLS IMPROVES. LAKE EFFECT SNOW POTENTIAL OFF OF LAKE ONTARIO... ONCE THE ARCTIC AIR STARTS WORKING ACROSS THE LAKE SUNDAY AFTERNOON AND EVENING...LAKE EFFECT SNOWS WILL PICK UP ALONG THE SOUTHEAST SHORE. LAKE PARAMETERS SHOW THE EQUILIBRIUM LEVELS RISING TO 5-8KFT LATE SUNDAY...THEN PICKING UP OVERNIGHT TO 10KFT OR SO BY MONDAY MORNING...BEFORE THE CAPPING INVERSION QUICKLY LOWERS LATE MONDAY AFTERNOON WITH RISING HEIGHTS / SUBSIDENCE UNDER THE BUILDING RIDGE. THE MEAN NORTHWEST FLOW DURING THIS TIME PERIOD WILL CONCENTRATE THE HEAVIEST LAKE SNOWS FROM EASTERN NIAGARA COUNTY ACROSS TO SOUTHWEST OSWEGO COUNTY...SIMILAR TO THE MOST RECENT LAKE EFFECT EVENT. EXPECT THE HIGHEST SNOW ACCUMULATIONS WILL BE IMMEDIATELY ALONG THE LAKE SHORE...AND WILL TAPER OFF QUICKLY INLAND...DUE TO THE MULTIBANDED STRUCTURE AND THE REDUCED FETCH DUE SOME ICE COVER ON LAKE ONTARIO. SHOULD THESE LAKE PARAMETERS HOLD...ADVISORY HEADLINES MAY EVENTUALLY BE NEEDED MAINLY FOR LOCATIONS IMMEDIATELY ALONG THE LAKE SHORE. TEMPERATURES ON MONDAY... FORECAST CONFIDENCE IS HIGH IN ANOTHER ROUND OF POTENTIALLY RECORD SETTING COLD AIR FOR MONDAY. GLOBAL MODELS AND THEIR ENSEMBLES ARE IN EXCELLENT AGREEMENT ON A STRONG 500 MB LOW PASSING NORTH OF NEW YORK DURING THE DAY MONDAY. NAEFS PERCENTILES SHOW FORECAST 850 MB TEMPERATURES ONCE AGAIN REACH RECORD VALUES FOR THE 1979-2009 CLIMATE PERIOD. THIS WILL TRANSLATE TO LOW TEMPERATURES MONDAY MORNING AND AGAIN TUESDAY MORNING RANGING FROM AROUND 0 NEAR LAKE ONTARIO TO TEENS BELOW ZERO AWAY FROM THE LAKE. HIGH TEMPERATURES ON MONDAY WILL LIKELY REMAIN WITHIN A FEW DEGREES EITHER SIDE OF 0. && .LONG TERM /TUESDAY THROUGH FRIDAY/... WHILE TEMPERATURES DURING THIS PERIOD WILL NOT BE AS BRUTAL AS THEY HAVE BEEN IN RECENT DAYS...THE PRESENCE OF A DEEP LONGWAVE TROUGH OVER NORTH AMERICA WITH A CONTINUED FLOW OUT OF THE CANADIAN ARCTIC WILL KEEP OUR MERCURY AT BELOW NORMAL LEVELS. A MODERATING SOUTHWESTERLY FLOW BETWEEN HIGH PRESSURE TO OUR SOUTH AND LOW PRESSURE APPROACHING FROM THE NORTHWEST WILL BRING ANOTHER SLIGHT WARM-UP WITH HIGH TEMPS BUMPING THE 20 DEGREE MARK IN SOME SPOTS UPPER TEENS ELSEWHERE. THE LOW TO THE NORTHWEST WILL BRING ANOTHER ROUND OF SNOW TUESDAY EVENING THROUGH MUCH OF WEDNESDAY. THERE MAY BE A MODERATE TO BRIEFLY HEAVY SNOW WITH THE PASSAGE OF AN ARCTIC FRONT ACCOMPANYING THE LOW. OTHERWISE...SNOW SHOULD BE LIGHT IN NATURE AND NOT POSE MUCH MORE THAN A FEW INCHES OF ACCUMULATION. THE COLDER AIR FOLLOWING THE LOW WILL NOT BE NEARLY AS COLD AS IN RECENT EVENTS. 850MB TEMPS DO FALL TO ABOUT -24C OVER LAKE ONTARIO ON WEDNESDAY NIGHT AND THURSDAY...AND WITH A WELL ALIGNED WESTERLY WIND WILL PRODUCE A BAND OF LAKE EFFECT SNOW ALONG THE SOUTH SHORE INLAND TO CENTRAL NY. SPRAWLING HIGH PRESSURE CENTERED OVER THE UPPER PLAINS TO BREADBASKET PROVINCES WILL BUILD EASTWARD ACROSS THE REGION ON THURSDAY NIGHT AND FRIDAY. THIS WILL DRYING AND SUBSIDENCE TO THE AREA WITH AN END OF THE LAKE EFFECT AND MORE SUNSHINE...EVEN THE OPPORTUNITY FOR A WARMING TREND. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... LIGHT SNOW WILL SPREAD ACROSS WRN/NCTRL NY TODAY AHEAD OF AN AREA OF LOW PRESSURE CROSSING THE GREAT LAKES. EXPECT CONDITIONS TO DETERIORATE TO IFR VSBYS THROUGH EARLY AFTERNOON...WITH VSBY LOWERING TO 1-2SM IN LIGHT SNOW. CONDITIONS SHOULD IMPROVE SOMEWHAT WITH THE PASSAGE OF THE LOW CENTER AS MAIN AREA OF ISENTROPIC LIFT MOVES OFF TO THE EAST...HOWEVER WINDS WILL ALSO BECOME WESTERLY...ALLOW FOR UPSLOPE MVFR CIGS TO LINGER. IN ADDITION...AS MID-LEVEL MOISTURE IS STRIPPED OUT BEHIND THE LOW THERE WILL BE A POTENTIAL FOR -FZDZ TO DEVELOP LATER TONIGHT AND LINGER INTO SUNDAY MORNING. OUTLOOK... SATURDAY OVERNIGHT...MVFR/IFR WITH SNOW LIKELY. SUNDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE. MONDAY...MVFR/IFR IN LAKE SNOW SOUTH OF LAKE ONTARIO. VFR ELSEWHERE. TUESDAY...VFR. WEDNESDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE. && .MARINE... WINDS SHOULD REMAIN RELATIVELY LIGHT OVER THE LAKES AS RELATIVELY WARM AIR SURGING NORTHWARDS ACROSS THE REGION WILL HELP KEEP STRONGER WINDS ALOFT. RELATIVELY TRANQUIL CONDITIONS ON LAKE ONTARIO WILL PERSIST THROUGH TONIGHT AS A WEAK AREA OF LOW PRESSURE CROSSES THE REGION. FRESHENING WESTERLY FLOW WILL DEVELOP BEHIND THE PASSING LOW SUNDAY AFTERNOON. AN ARCTIC FRONT DROPPING ACROSS THE LAKES SUNDAY NIGHT WILL LIKELY BRING ANOTHER ROUND OF SMALL CRAFT ADVISORIES WITH BRISK WNW FLOW LASTING THROUGH MONDAY WITH WINDS BACKING TO THE SW TUESDAY AHEAD OF ANOTHER CLIPPER THAT IS EXPECTED TO PASS NORTH OF THE GREAT LAKES. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST SUNDAY FOR NYZ001-002- 006>008-010>012-019>021-085. MARINE...NONE. && $$ SYNOPSIS...WOOD NEAR TERM...APFFEL/WOOD SHORT TERM...CHURCH LONG TERM...CHURCH/WCH AVIATION...APFFEL/WOOD MARINE...WOOD
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1007 AM EST SAT FEB 21 2015 .SYNOPSIS... AN ELONGATED AREA OF LOW PRESSURE OVER THE CENTRAL UNITED STATES WILL CROSS THE GREAT LAKES TODAY BRINGING WIDESPREAD...MAINLY LIGHT...SNOWFALL TO WESTERN AND NORTH CENTRAL NEW YORK TODAY INTO TONIGHT ALONG WITH RELATIVELY WARMER TEMPERATURES IN THE 20S. AREAS OF FREEZING DRIZZLE WILL BE POSSIBLE IN THE WAKE OF THE SYSTEM LATER TONIGHT INTO SUNDAY BEFORE TEMPERATURES PLUNGE SUNDAY NIGHT AS ANOTHER ARCTIC FRONT SWEEPS ACROSS THE GREAT LAKES...BRINGING POTENTIALLY RECORD BREAKING COLD ALONG WITH LAKE EFFECT SNOW SHOWERS BY MONDAY. WHILE MONDAY WILL BE THE COLDEST DAY OF THE PERIOD...TEMPERATURES ARE EXPECTED TO REMAIN BELOW AVERAGE THROUGH NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AT 1000 AM...LIGHT SNOW HAS STARTED TO SPREAD INTO FAR WESTERN NEW YORK...WITH THIS AREA EXPECTED TO CONTINUE TO SPREAD AND ACROSS THE ENTIRE CWA BY EARLY AFTERNOON. SYNOPTIC SUPPORT STEMS FROM A BROAD AREA OF WARM AIR ADVECTION...WITH SOME MODEST UPPER LEVEL SUPPORT WITH A MODEST SHORTWAVE EMBEDDED IN A CYCLONIC FLOW. RADAR SHOWS SOME LOW LEVEL ENHANCEMENT ACROSS SOUTHERN ONTARIO AND INTO THE NIAGARA FRONTIER WHICH OFTEN DEVELOPS IN THIS AREAS WHEN THERE IS A SOUTHERLY FLOW. HIGH RESOLUTION GUIDANCE CAPTURES THIS...WITH THIS ENHANCEMENT LIKELY CONTINUE THROUGH 18Z OR SO...WHEN WINDS DIMINISH AND SHIFT TO THE SSW. OTHERWISE...STEADIEST SNOWS SHOULD BE ACROSS WESTERN PORTIONS OF THE SOUTHERN TIER THROUGH EARLY AFTERNOON WHERE THERE IS THE MOST MOISTURE AND SYNOPTIC SCALE LIFT. THE HRRR SEEMS TO HAVE A GOOD HANDLE ON THESE TRENDS...BUT IS RUNNING ABOUT AN HOUR SLOW WITH ITS TIMING. EXPECT SNOWFALL TO BE ACCORDINGLY LIGHT WITH MOST AREAS SEEING A GENERAL 2 TO 4 INCHES THROUGH THIS EVENING. SOUTHERLY DOWNSLOPING IN THE VICINITY OF THE FINGER LAKES MAY RESULT IN ACCUMULATIONS ON THE LOWER END OF THESE VALUES WHILE SIMILAR UPSLOPING ONTO THE TUG HILL PLATEAU SHOULD YIELD SLIGHTLY HIGHER ACCUMULATIONS IN THE NEIGHBORHOOD OF 4 TO 7 INCHES THROUGH TONIGHT. HENCE A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR OSWEGO/LEWIS COUNTIES TO COVER THESE SLIGHTLY HIGHER ACCUMULATIONS. SNOW WILL TAPER OFF FROM WEST TO EAST AS THE UPPER LEVEL JET AND DEEPER MOISTURE TRANSLATES TO THE EAST COAST. EVEN AS THE DEEPER MID-LEVEL MOISTURE IS STRIPPED OUT...WEAK ASCENT DUE TO APPROACHING MID/UPPER LEVEL TROUGHING ALONG WITH WESTERLY UPSLOPE FLOW MAY RESULT IN A TRANSITION FROM LINGERING SNOW SHOWERS TO AREAS OF FREEZING DRIZZLE LATER ON TONIGHT...PARTICULARLY ACROSS UPSLOPE AREAS OF WESTERN NEW YORK AND EVENTUALLY THE NORTH COUNTRY. REGARDING TEMPERATURES...AFOREMENTIONED WARM ADVECTION WILL CONTINUE TO PUSH TEMPERATURES UPWARDS THROUGH THE DAY TODAY WITH HIGHS CLIMBING INTO THE 20S BY THIS AFTERNOON. TEMPERATURES WILL CONTINUE TO CLIMB INTO THE UPPER 20S TONIGHT AS THE WARMEST AIR SURGES NORTH ACROSS THE REGION IN ADVANCE OF A SURFACE COLD FRONT THAT CROSSES THE REGION SUNDAY. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... SUNDAY WILL START OFF WITH WITH BROAD CYCLONIC FLOW ALOFT AND A COLD AIR ADVECTION REGIME BEHIND THE DEPARTING SURFACE LOW. FORECAST SOUNDINGS INDICATE THAT MID-LEVEL DRY AIR WILL BE IN PLACE ACROSS WESTERN AND CENTRAL NEW YORK...WITH PLENTIFUL LOW-LEVEL MOISTURE IN THE WESTERLY FLOW. LOW-LEVEL TEMPERATURES ARE PROGGED TO BE IN THE -4 TO -10C RANGE AND SATURATED...WITH WITH DRY AIR IN PLACE IN THE MID-LEVEL...TYPICAL OF A FREEZING DRIZZLE SOUNDING. EXPECT AREAS OF FREEZING DRIZZLE WITH A CHANCE FOR SOME LIGHT SNOW/FLURRIES MIXED IN A TIMES....ESPECIALLY ALONG THE UPSLOPE AREAS OF THE WESTERN SOUTHERN TIER AND THE TUG HILL AREA. BY THE AFTERNOON...THE FREEZING DRIZZLE CHANCES SHOULD RAPIDLY COME TO AN END AS COLDER AIR CONTINUES TO ADVECT INTO THE AREA...PUSHING THE LOW-LEVEL TEMPERATURES INTO THE DENDRITIC GROWTH TEMPERATURE RANGE...ALLOWING FOR A CHANGE OVER TO SNOW ACROSS THE AREA. TEMPERATURES ON SUNDAY WILL BE FAIRLY STAGNANT IN THE LOW 20S THROUGH THE MORNING...THEN WILL START TO FALL THROUGH THE AFTERNOON AS THE TRUE ARCTIC SOURCED AIR FINALLY STARTS TO PUSH INTO WESTERN NEW YORK. THE BOTTOM WILL FALL OUT SUNDAY EVENING AS TEMPERATURES PLUNGE TOWARD ZERO BY MIDNIGHT AS THE CORE OF THE -24C TO -30C 850 MB AIR ARRIVES. ACCOMPANYING THE ARCTIC FRONT...WILL BE SOME INCREASED WINDS AS THE PRESSURE GRADIENT TIGHTENS BETWEEN AN IMPRESSIVE 1049MB HIGH OVER THE CENTRAL CONUS AND THE 999MB LOW OVER NEW BRUNSWICK. THE COMBINATION OF TEMPERATURES PLUNGING AND STEADY WINDS IN THE CAA ACROSS THE AREA WILL LIKELY PROMPT ANOTHER PERIOD OF BITTER WIND CHILLS THAT WILL EVENTUALLY NEED HEADLINES ONCE CONFIDENCE ON THE MAGNITUDE OF THE WIND CHILLS IMPROVES. LAKE EFFECT SNOW POTENTIAL OFF OF LAKE ONTARIO... ONCE THE ARCTIC AIR STARTS WORKING ACROSS THE LAKE SUNDAY AFTERNOON AND EVENING...LAKE EFFECT SNOWS WILL PICK UP ALONG THE SOUTHEAST SHORE. LAKE PARAMETERS SHOW THE EQUILIBRIUM LEVELS RISING TO 5-8KFT LATE SUNDAY...THEN PICKING UP OVERNIGHT TO 10KFT OR SO BY MONDAY MORNING...BEFORE THE CAPPING INVERSION QUICKLY LOWERS LATE MONDAY AFTERNOON WITH RISING HEIGHTS / SUBSIDENCE UNDER THE BUILDING RIDGE. THE MEAN NORTHWEST FLOW DURING THIS TIME PERIOD WILL CONCENTRATE THE HEAVIEST LAKE SNOWS FROM EASTERN NIAGARA COUNTY ACROSS TO SOUTHWEST OSWEGO COUNTY...SIMILAR TO THE MOST RECENT LAKE EFFECT EVENT. EXPECT THE HIGHEST SNOW ACCUMULATIONS WILL BE IMMEDIATELY ALONG THE LAKE SHORE...AND WILL TAPER OFF QUICKLY INLAND...DUE TO THE MULTIBANDED STRUCTURE AND THE REDUCED FETCH DUE SOME ICE COVER ON LAKE ONTARIO. SHOULD THESE LAKE PARAMETERS HOLD...ADVISORY HEADLINES MAY EVENTUALLY BE NEEDED MAINLY FOR LOCATIONS IMMEDIATELY ALONG THE LAKE SHORE. TEMPERATURES ON MONDAY... FORECAST CONFIDENCE IS HIGH IN ANOTHER ROUND OF POTENTIALLY RECORD SETTING COLD AIR FOR MONDAY. GLOBAL MODELS AND THEIR ENSEMBLES ARE IN EXCELLENT AGREEMENT ON A STRONG 500 MB LOW PASSING NORTH OF NEW YORK DURING THE DAY MONDAY. NAEFS PERCENTILES SHOW FORECAST 850 MB TEMPERATURES ONCE AGAIN REACH RECORD VALUES FOR THE 1979-2009 CLIMATE PERIOD. THIS WILL TRANSLATE TO LOW TEMPERATURES MONDAY MORNING AND AGAIN TUESDAY MORNING RANGING FROM AROUND 0 NEAR LAKE ONTARIO TO TEENS BELOW ZERO AWAY FROM THE LAKE. HIGH TEMPERATURES ON MONDAY WILL LIKELY REMAIN WITHIN A FEW DEGREES EITHER SIDE OF 0. && .LONG TERM /TUESDAY THROUGH FRIDAY/... WHILE TEMPERATURES DURING THIS PERIOD WILL NOT BE AS BRUTAL AS THEY HAVE BEEN IN RECENT DAYS...THE PRESENCE OF A DEEP LONGWAVE TROUGH OVER NORTH AMERICA WITH A CONTINUED FLOW OUT OF THE CANADIAN ARCTIC WILL KEEP OUR MERCURY AT BELOW NORMAL LEVELS. A MODERATING SOUTHWESTERLY FLOW BETWEEN HIGH PRESSURE TO OUR SOUTH AND LOW PRESSURE APPROACHING FROM THE NORTHWEST WILL BRING ANOTHER SLIGHT WARM-UP WITH HIGH TEMPS BUMPING THE 20 DEGREE MARK IN SOME SPOTS UPPER TEENS ELSEWHERE. THE LOW TO THE NORTHWEST WILL BRING ANOTHER ROUND OF SNOW TUESDAY EVENING THROUGH MUCH OF WEDNESDAY. THERE MAY BE A MODERATE TO BRIEFLY HEAVY SNOW WITH THE PASSAGE OF AN ARCTIC FRONT ACCOMPANYING THE LOW. OTHERWISE...SNOW SHOULD BE LIGHT IN NATURE AND NOT POSE MUCH MORE THAN A FEW INCHES OF ACCUMULATION. THE COLDER AIR FOLLOWING THE LOW WILL NOT BE NEARLY AS COLD AS IN RECENT EVENTS. 850MB TEMPS DO FALL TO ABOUT -24C OVER LAKE ONTARIO ON WEDNESDAY NIGHT AND THURSDAY...AND WITH A WELL ALIGNED WESTERLY WIND WILL PRODUCE A BAND OF LAKE EFFECT SNOW ALONG THE SOUTH SHORE INLAND TO CENTRAL NY. SPRAWLING HIGH PRESSURE CENTERED OVER THE UPPER PLAINS TO BREADBASKET PROVINCES WILL BUILD EASTWARD ACROSS THE REGION ON THURSDAY NIGHT AND FRIDAY. THIS WILL DRYING AND SUBSIDENCE TO THE AREA WITH AN END OF THE LAKE EFFECT AND MORE SUNSHINE...EVEN THE OPPORTUNITY FOR A WARMING TREND. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... LIGHT SNOW WILL SPREAD ACROSS WRN/NCTRL NY TODAY AHEAD OF AN AREA OF LOW PRESSURE CROSSING THE GREAT LAKES. EXPECT CONDITIONS TO DETERIORATE TO IFR VSBYS THROUGH EARLY AFTERNOON...WITH VSBY LOWERING TO 1-2SM IN LIGHT SNOW. CONDITIONS SHOULD IMPROVE SOMEWHAT WITH THE PASSAGE OF THE LOW CENTER AS MAIN AREA OF ISENTROPIC LIFT MOVES OFF TO THE EAST...HOWEVER WINDS WILL ALSO BECOME WESTERLY...ALLOW FOR UPSLOPE MVFR CIGS TO LINGER. IN ADDITION...AS MID-LEVEL MOISTURE IS STRIPPED OUT BEHIND THE LOW THERE WILL BE A POTENTIAL FOR -FZDZ TO DEVELOP LATER TONIGHT AND LINGER INTO SUNDAY MORNING. OUTLOOK... SATURDAY OVERNIGHT...MVFR/IFR WITH SNOW LIKELY. SUNDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE. MONDAY...MVFR/IFR IN LAKE SNOW SOUTH OF LAKE ONTARIO. VFR ELSEWHERE. TUESDAY...VFR. WEDNESDAY...SCATTERED SNOW SHOWERS WITH MVFR/IFR POSSIBLE. && .MARINE... WINDS SHOULD REMAIN RELATIVELY LIGHT OVER THE LAKES AS RELATIVELY WARM AIR SURGING NORTHWARDS ACROSS THE REGION WILL HELP KEEP STRONGER WINDS ALOFT. RELATIVELY TRANQUIL CONDITIONS ON LAKE ONTARIO WILL PERSIST THROUGH TONIGHT AS A WEAK AREA OF LOW PRESSURE CROSSES THE REGION. FRESHENING WESTERLY FLOW WILL DEVELOP BEHIND THE PASSING LOW SUNDAY AFTERNOON. AN ARCTIC FRONT DROPPING ACROSS THE LAKES SUNDAY NIGHT WILL LIKELY BRING ANOTHER ROUND OF SMALL CRAFT ADVISORIES WITH BRISK WNW FLOW LASTING THROUGH MONDAY WITH WINDS BACKING TO THE SW TUESDAY AHEAD OF ANOTHER CLIPPER THAT IS EXPECTED TO PASS NORTH OF THE GREAT LAKES. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR NYZ006-008. MARINE...NONE. && $$ SYNOPSIS...WOOD NEAR TERM...APFFEL/WOOD SHORT TERM...CHURCH LONG TERM...CHURCH/WCH AVIATION...APFFEL/WOOD MARINE...WOOD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
930 PM EST SUN FEB 22 2015 .SYNOPSIS... A MILD AND MOIST AIR MASS WILL LIE ACROSS THE AREA INTO TONIGHT. RAIN ASSOCIATED WITH A COLD FRONTAL PASSAGE WILL BE LIGHT TONIGHT...BUT WEAK LOW PRESSURE WILL MOVE ALONG THE STALLED FRONT...SPREADING MORE SIGNIFICANT RAIN NORTHWARD ON MONDAY. COLD AIR WILL RETURN LATE MONDAY AS ARCTIC HIGH PRESSURE SNEAKS BACK ACROSS THE REGION INTO TUE. COLD AND UNSETTLED WEATHER IS EXPECTED DURING THE UPCOMING WEEK AS CHILLY HIGH PRESSURE AND GULF MOISTURE INTERACT. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... AS OF 930 PM SUNDAY...SCATTERED AREAS OF RAIN IS LEADING A FRONTAL BOUNDARY THAT WILL SLOWLY PUSH OFF THE COAST BY MORNING. THE AREA OF RAIN IS PRODUCING TOTAL OF LESS THAN A TENTH OF AN INCH. THE LATEST RUN OF THE HRRR IS SHOWING THE COVERAGE OF THE RAIN BECOMING MORE WIDESPREAD OVERNIGHT. TEMPERATURES ARE EXPECTED TO FALL ONLY TO AROUND 40 IN THE NORTHWEST TO THE UPPER 40S SOUTH AND WEST OF MYRTLE BEACH. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... AS OF 330 PM SUNDAY...WAVE OF LOW PRESSURE RIDING ALONG LINGERING FRONT MON MORNING WILL MOVE OUT OF AREA MON AFTN AS HIGH PRESSURE BUILDS DOWN FROM THE NORTHWEST. BEST LIFT WILL RUN FROM SOUTHWEST TO NORTHEAST ALONG BOUNDARY AS IT SHIFTS FARTHER SOUTH THROUGH THE DAY. THEREFORE THE GREATEST POPS WILL BE IN THE MORNING...FAIRLY WIDESPREAD ACROSS MUCH OF THE AREA AND THEN DIMINISHING THROUGH THE AFTERNOON AS DIGGING MID TO UPPER TROUGH AND HIGH PRESSURE PUSH FRONT SOUTHWARD. EXPECT A COOL RAIN AS TEMPS DROP FROM MID 40S IN THE MORNING DOWN TO 30S BY AFTN. LATEST SOUNDINGS KEEP SATURATED COLUMN ABOVE FREEZING UNTIL MON AFTN INTO EARLY EVE. ONCE COLUMN GOES BELOW FREEZING IT DRIES OUT...LEAVING ONLY A THIN SATURATED LAYER BETWEEN 6 TO 7 K FT AFTER 00Z ON NAM SOUNDING. THEREFORE WILL FOLLOW PREVIOUS FORECAST KEEPING POPS OUT OF FORECAST ONCE FZN PCP IS POSSIBLE LATE MONDAY. COASTAL CAROLINAS WILL REMAIN AT THE BASE OF A VERY BROAD UPPER TROUGH THROUGH REMAINDER OF THE PERIOD AS COOL SFC HIGH EXTENDS DOWN FROM THE NORTH. FRONT WILL LINGER FROM SW TO NE SOUTH OF FORECAST AREA WITH COOL AIR LOCKED IN PLACE MON NIGHT THROUGH TUES. TEMPS MONDAY NIGHT WILL FALL INTO THE 20S IN PLENTY OF CAA. TEMPS AT H85 DROP FROM AROUND 7 C MON MORNING DOWN TO -3C BY TUES MORNING. MODELS CONTINUE TO SHOW A PERTURBATION MOVING ACROSS THE CAROLINAS WITH ANOTHER WAVE OF LOW PRESSURE RIDING ALONG THE FRONT OVERNIGHT MONDAY INTO TUES AS THE FRONT STARTS LIFTING NORTH. NAM IS MOST AGGRESSIVE IN BRINGING MOISTURE AND LIFT NORTH EARLY IN THE DAY ON TUES. FOR NOW HAVE INCLUDED SLIGHT CHC UP THROUGH PORTIONS OF FLORENCE ACROSS TO THE GRAND STRAND AND SOUTH INITIALLY AND SPREAD NORTH REMAINING ALIGNED MORE ALONG THE COAST LATER ON TUES. HAVE INCLUDED SOME MIXED PCP AS SOUNDINGS REMAIN BELOW ZERO UP THROUGH THE COLUMN MON NIGHT INTO EARLY TUES WITH A WARM NOSE DEVELOPING INTO THE DAY BUT COLD TEMPS HOLDING ON. AS FRONT TRIES TO MOVE NORTH EXPECT PCP TO SPREAD FARTHER NORTH ON TUES. SHOULD GET PUSHED SOUTH AND EAST AS ANOTHER FRONT MOVES IN FROM THE WEST BY WED MORNING. TEMPS SHOULD REMAIN COOL THROUGH THE PERIOD. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 PM SUNDAY...LARGE...BUT NOT EXCEPTIONALLY DEEP...TROUGH WILL PERSIST ACROSS THE EAST INTO THE UPCOMING WEEKEND MAINTAIN COLD AND UNSETTLED CONDITIONS FOR MUCH OF THE EXTENDED. COLD FRONT STALLED WELL SOUTH OF THE AREA WILL SERVE AS THE BAROCLINIC GRADIENT ALONG WHICH AN ACTIVE SOUTHERN STREAM WILL SPAWN SEVERAL WAVES OF LOW PRESSURE. WHILE NONE OF THESE WILL BE IMPRESSIVELY STRONG...EACH ONE WILL BRING AT LEAST A CHANCE OF PRECIP TO THE AREA. TWO QUESTIONS WILL SURROUND EACH PASSING WAVE OF LOW PRESSURE HOWEVER...HOW MUCH PRECIP WILL EXTEND NORTH FROM THE LOW...AND WHETHER COLD ENOUGH AIR WILL BE IN PLACE FOR MIXED P-TYPE. THE FIRST OF THESE...WEDNESDAY NIGHT AND THURSDAY...LOOKS NOW TO BE THE MOST SIGNIFICANT OF THE WEEK. GUIDANCE IS TRACKING THIS SURFACE LOW A LITTLE FURTHER WEST THAN PREVIOUS RUNS...AND THUS SLINGING MORE PRECIP INTO THE CAROLINAS. ADMITTEDLY...THE E-W ORIENTED BAROCLINIC ZONE DOES NOT`T SUPPORT A VERY FAR WEST TRACK AND WILL LEAN MORE ON THE DRIER GFS...BUT WIDESPREAD CLOUDS WITH PERIODS OF PRECIP ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY. WITH COLD HIGH PRESSURE IN PLACE RAIN COULD MIX WITH SOME FREEZING/FROZEN PRECIP...EVEN THOUGH RAIN IS EXPECTED TO BE THE PRIMARY P-TYPE. THE ECMWF...WHICH IS MORE ROBUST WITH ITS PRECIP...IS ALSO COLDER...BUT EVEN THE GFS DEPICTS A PERIOD OF MIXED PRECIP. LOCAL TOP-DOWN METHODOLOGY PRODUCES PRIMARILY RAIN AS EXPECTED...BUT HAVE LEFT A PERIOD OF MIX PRECIP...RAIN AND SNOW WITH SNOW ONLY FAR NW...LATE WED NIGHT. QPF WILL BE LIGHT AND POP IS LOW...BUT SNOWFLAKES ARE POSSIBLE WED NIGHT BEFORE TEMPS WARM TO SUPPORT ONLY RAIN DURING THURSDAY. A PERIOD OF DRIER WEATHER IS EXPECTED LATE THURSDAY INTO FRIDAY...BEFORE ANOTHER LOW PRESSURE MOVES ALONG THE STALLED BOUNDARY TO THE SOUTH. HOWEVER...EVEN DURING THIS "DRIER" PERIOD A SCHC POP REMAINS WARRANTED DUE TO WAVES OF LOW PRESSURE ALONG THE OFFSHORE BAROCLINIC GRADIENT - AND THERE IS LOW CONFIDENCE IN THE TIMING/TRACK OF THESE FEATURES. THE PAST FEW DAYS...ECMWF/GFS HAD SHOWN GOOD AGREEMENT IN BRINGING MORE SIGNIFICANT PRECIP LOCALLY FRIDAY INTO SATURDAY...MUCH OF WHICH WOULD BE OF THE FREEZING-TO-LIQUID TRANSITION VARIETY. TODAY...GUIDANCE HAS BACKED OFF CONSIDERABLY...WHICH MAY MAKE SENSE DUE TO THE EXPECTED QUICK E/NE TRACK OF SURFACE FEATURES. STILL...AM INCLINED TO MAKE ONLY MINIMAL CHANGES TO THE FRI/SAT TIMEFRAME AS THIS REPRESENTS A NEW SOLUTION...AND WILL LEAVE LOW MENTIONABLE POP WITH MIXED P-TYPE. BY SUNDAY THE LONGWAVE TROUGH WILL BEGIN TO ERODE...FINALLY...BRINGING BRIGHTER WEATHER AND MORE SEASONABLE TEMPERATURES AFTER THE FIRST 4 DAYS OF THE EXTENDED CONTINUE WELL BELOW NORMAL. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... AS OF 00Z...PCPN COMING TO AN END ACROSS THE INLAND TERMINALS WITHIN THE NEXT HOUR AND ACROSS THE SC COASTAL TERMINALS WILL LEAVE PCPN TEMPO GROUP FOR ILM AS WE CAN STILL SEE SOME PCPN DURING THE NEXT FEW HOURS. MOST OF THE STEADY MODERATE RAIN WILL FALL BETWEEN THE COASTAL TERMINALS AND THE INLAND TERMINALS. WE WILL SEE A LULL IN THE ACTIVITY FOR A FEW HOURS BEFORE THE NEXT ROUND OF PCPN STARTS TO MOVE IN/FILL IN ACROSS THE RADAR AS A COLD FRONT DROPS TO THE SE ACROSS THE CWA. WEAK AREA OF LOW PRESSURE TO RIDE UP ALONG THIS FRONTAL BOUNDARY AND WILL SPREAD A LIGHT TO MODERATE STEADY RAIN ACROSS THE TERMINALS AFTER 04Z THROUGH ABOUT 18Z-21Z. WILL FORECAST IFR ACROSS THE TERMINALS OVERNIGHT IN VSBY/CEILINGS AND COULD POSSIBLY SEE LIFR. AS THE FRONT MOVES ACROSS THE AREA THE PRESSURE GRADIENT WILL TIGHTEN UP DURING THE DAY AND WINDS WILL INCREASE AND BE GUSTY FROM THE NORTH-NORTH NORTHEAST WITH GUST AS HIGH AS 30KTS IN THE AFTERNOON. CONDITIONS WILL START TO IMPROVE IN REGARDS TO VSBY/CEILING TOWARDS THE END OF THE PERIOD...BUT TERMINALS WILL STILL BE IN MVFR AT BEST. EXTENDED OUTLOOK...UNSETTLED WEATHER IS EXPECTED THROUGH THE EXTENDED...WITH POSSIBLE IFR/MFR CONDITIONS AND SEVERAL CHANCES FOR PRECIPITATION. && .MARINE... .NEAR TERM /THROUGH TONIGHT/... AS OF 930 PM SUNDAY...WINDS ARE RELATIVELY LIGHT OVER THE WATERS WITH SEAS RANGING FROM 2 TO 4 FEET. FRYING PAN SHOALS IS NOW REPORTING SEAS DOWN TO 5 FEET JUST OUTSIDE THE COASTAL WATERS. A LIGHT RAIN IS EXPECTED OVERNIGHT AS A COLD FRONT SLOWLY APPROACHES THE WATERS BY DAYBREAK. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 330 PM SUNDAY...SMALL CRAFT ISSUED FOR MONDAY THROUGH EARLY TUES AS ARCTIC HIGH PRESSURE BUILDS DOWN BEHIND COLD FRONT. THIS COLD FRONT WILL LINGER SOUTH OF AREA KEEPING TIGHTENED GRADIENT FLOW THROUGH MON NIGHT AND ALONG WITH PLENTY OF CAA...WINDS AND SEAS WILL RAMP UP TO 5 TO 7 FT IN STRONG NORTHERLY FLOW UP AROUND 25 KTS IN OUTER WATERS. THE STRONG N TO OFF SHORE COMPONENT WILL KEEP HIGHEST SEAS AWAY FROM SHORE. WINDS START DECREASING TUE AS ELONGATED SURFACE RIDGE AXIS MOVES TO THE COAST AND GRADIENT RELAXES. LIGHT WINDS LATE TUE CONTINUE TUE NIGHT AS THE WEAK HIGH EXITS NORTHEAST AND WINDS BACK TO WEST-SOUTHWEST. SEAS FALL TO 3 TO 5 FT LATER TUE AND 2 TO 4 FT TUE NIGHT. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...DIFFUSE PRESSURE PATTERN WEDNESDAY LEAVES A WEAK GRADIENT AND LIGHT W-NW WINDS ACROSS THE WATERS. THIS WILL CHANGE RAPIDLY WEDNESDAY NIGHT AND INTO THURSDAY AS A LOW PRESSURE SYSTEM MOVES SE OF THE WATERS. THE LOW TRACK WILL REMAIN OUTSIDE THE COASTAL WATERS...BUT THE GRADIENT AROUND THIS LOW WILL CAUSE NE WINDS TO INCREASE STEADILY...BECOMING 15-20 KTS EARLY THURSDAY. AS THE LOW PULLS AWAY THURSDAY NIGHT...THE GRADIENT WILL REMAIN PINCHED THANKS TO A STALLED COLD FRONT SOUTH OF THE AREA...ALONG WHICH ANOTHER LOW PRESSURE WILL DEVELOP AND MOVE OFF THE COAST FRIDAY. THIS CONTINUES THE NE WINDS AT 15-20 KTS THROUGH THE END OF THE PERIOD. SEAS WEDNESDAY WILL BE JUST 1-3 FT ON THE LIGHT AND VARIABLE WINDS...BUT WILL INCREASE QUICKLY WED NIGHT ON THE INCREASING NE FETCH. WAVE HEIGHTS BUILD TO 4-6 FT THURSDAY MORNING...AND THEN EVEN A LITTLE HIGHER ON FRIDAY...AND AN EXTENDED SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR MOST OF THURSDAY AND FRIDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 AM MONDAY TO 2 PM EST TUESDAY FOR AMZ250-252-254-256. && $$ NEAR TERM...HAWKINS SHORT TERM...RGZ LONG TERM...JDW AVIATION...MAC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
400 PM EST SAT FEB 21 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND MOVE THROUGH SUNDAY AFTERNOON AND EVENING. LOW PRESSURE WILL TRACK SOUTHEAST OF THE AREA LATE SUNDAY NIGHT INTO MONDAY THEN HIGH PRESSURE WILL PASS TO THE NORTH MONDAY NIGHT AND MOVE OFF THE COAST TUESDAY. ANOTHER LOW PRESSURE AREA WILL PASS TO THE SOUTHEAST OF THE REGION WEDNESDAY NIGHT INTO THURSDAY FOLLOWED BY HIGH PRESSURE BUILDING INTO THE REGION FROM THE NORTH FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 PM SAT...LATEST SFC ANALYSIS SHOWS WARM FRONT BISECTING THE CWA FROM NORTH TO SOUTH...GENERALLY FROM OREGON INLET REGION INTO THE COASTAL PLAIN NEAR ROCKY MOUNT.FRONT WILL CONTINUE TO LIFT NORTHWARD THIS AFTERNOON AND EARLY EVENING...WITH SLY FLOW DEVELOPING ACROSS ALL OF THE REGION. TEMPS WARMED VERY QUICKLY THIS AFTERNOON ONCE WARM FRONT WENT THROUGH...WITH CURRENT TEMPS PRED IN THE MID 50S ACROSS THE REGION...THOUGH HANGING TOUGH IN THE LOW/MID 40S FOR THE ALBEMARLE SOUND REGION AND NORTHERN OUTER BANKS. VERY MILD NIGHT EXPECTED...ESP COMPARED TO PAST SEVERAL NIGHTS. EXPECT TO SEE NON- DIURNAL TEMP CURVE FOR MOST LOCATIONS WITH LOWS IN THE LOW/UPPER 40S. LATEST RADAR IMAGERY SHOWS AREA OF LIGHT SHOWERS TO THE SOUTH...MOVING INTO THE SW CWA. TRENDED POPS BASED ON HRRR AND NSSL WRF...WITH AREA OF SHOWERS MOVING INTO THE REGION THIS EVENING...THEN MOVING OFF THE COAST AS ANOTHER AREA APPROACHES FROM THE WEST EARLY SUNDAY MORNING. CAPPED POS AT HIGH CHANCE/LOW LIKELY. && .SHORT TERM /SUNDAY/... AS OF 330 PM SAT...COLD FRONT WILL APPROACH FROM THE WEST SUNDAY...MOVING THROUGH THE REGION LATE SUN AFTERNOON AND SUN NIGHT. WILL MAINTAIN LIKELY POPS FOR MOST OF THE AREA SUN...WITH SHOWERS TAPERING OFF FROM WEST TO EAST DURING THE AFTERNOON/EVENING. WARM TEMPS EXPECTED AGAIN WITH LOW LEVEL THICKNESS VALUES AND SLY FLOW SUPPORTING HIGHS IN THE MID 50S/LOW 60S. && .LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/... AS OF 400 PM SATURDAY...TRICKY FORECAST AS TEMPERATURES WILL BE MARGINAL FOR WINTRY WEATHER LATE SUNDAY NIGHT AND ESPECIALLY MONDAY. THE COLD FRONT WILL CROSS THE AREA SUNDAY NIGHT AND SHOULD BE JUST SOUTH OF THE AREA BY 12Z MONDAY. A WAVE IS THEN FORECAST TO FORM ALONG THE FRONT AND MOVE EAST ALONG THE BOUNDARY BRINGING WIDESPREAD RAIN TO THE AREA MAINLY AFTER MIDNIGHT SUNDAY NIGHT. THE LOW LEVEL NORTHERLY FLOW WILL BE STRENGTHENING LATE SUNDAY NIGHT AND MONDAY AND THIS PULL DOWN INCREASINGLY COLDER AIR INTO THE REGION MONDAY CAUSING THE PRECIPITATION TO CHANGE FROM RAIN TO FREEZING RAIN AND SLEET AND EVENTUALLY SNOW FROM NORTH TO SOUTH. ALTHOUGH SIGNIFICANT PRECIPITATION IS EXPECTED MUCH OF IT IS EXPECTED TO FALL AS RAIN WHICH WILL LIMIT THE IMPACTS OF WINTRY PRECIPITATION ACROSS THE AREA. OTHER LIMITING FACTORS WILL BE THE WARM GROUND AND THE SURFACE TEMPERATURES EXPECTED TO BE JUST ABOVE FREEZING. THUS WILL NOT BE ISSUING ANY WATCHES OR ADVISORIES AT THIS TIME. THE NAM AND GFS WERE COLDER THAN THE ECMWF AND INDICATED MORE OF A THREAT WHILE THE CMC INDICATED MOSTLY RAIN CHANGING OVER TO SLEET/SNOW AT THE END. THINK MOST OF IF NOT ALL OF THE PRECIPITATION ENDS BEFORE 00Z TUESDAY. THE FORECAST FOR THE REMAINDER OF THE PERIOD STILL IS BELOW NORMAL CONFIDENCE BUT IT NOW APPEARS THAT TUESDAY SHOULD BE MAINLY DRY WITH ONLY A SLIGHT CHANCE OF A SPRINKLE OR FLURRY. THE NEXT CHANCE FOR SIGNIFICANT PRECIPITATION IS FORECAST LATE WEDNESDAY INTO THURSDAY AS ANOTHER LOW TRACKS SOUTHEAST OF THE AREA. AGAIN WE COULD SEE P TYPE ISSUES WITH THIS SYSTEM IF MOISTURE MATERIALIZES WITH THIS SYSTEM. WILL INDICATE MAINLY DRY WEATHER FRIDAY AND THEN COULD SEE RAIN DEVELOP ON SATURDAY POSSIBLY STARTING OUT AS WINTRY MIX ESPECIALLY IF IT DEVELOPS FRIDAY NIGHT. TEMPERATURES WILL CONTINUE THEIR TREND OF RUNNING BELOW NORMAL DURING THE PERIOD. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... SHORT TERM /THROUGH 18Z SUNDAY/... BKN/OVC STRATOCU WITH BASES 3500-4000 FT HAS MOVED IN OVER THE AREA THIS AFTERNOON. EXPECT THAT CLOUD BASES WILL LOWER INTO THE HIGH MVFR CATEGORY AS MOIST LOW LEVEL SOUTHERLY FLOW STRENGTHENS THIS EVENING. ALSO SHORT RANGE MODELS ARE FAIRLY CONSISTENT IN DEVELOPING A BAND OF SHOWERS ACRS THE COASTAL PLAIN THIS EVENING AND MOVING IT TOWARD THE COAST EARLY SUNDAY MORNING WHICH WILL REINFORCE MVFR CONDITIONS. EXPECT LOWERING CIGS/VSBYS INTO MAINLY IFR CATEGORY LATE TONIGHT AS LOW LEVEL MOISTURE THICKENS IN A WEAK NOCTURNAL INVERSION. LOW LEVEL MOISTURE WILL BE SLOW TO SCOUR OUT AFTER SUNRISE SUNDAY BUT EXPECT CIGS RETURNING TO MVFR BY MIDDAY TO EARLY AFTERNOON. LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 400 PM SATURDAY...LOOKING SUB VFR CONDITIONS THROUGH MONDAY NIGHT DUE TO WIDESPREAD PRECIPITATION LATE SUNDAY NIGHT INTO MONDAY AFTERNOON AND THE LIKELIHOOD THAT LOW CLOUDS PERSIST INTO MONDAY NIGHT. EXPECTING DRIER WEATHER TUESDAY INTO WEDNESDAY WITH VFR CONDITIONS THEN MORE PRECIPITATION IS EXPECTED LATE WEDNESDAY INTO THURSDAY WITH SUB VFR CONDITIONS. && .MARINE... SHORT TERM /THROUGH SUNDAY/... AS OF 330 PM SAT...LATEST OBS SHOW SE/S WINDS 10-20KT AND SEAS 2-4FT. WARM FRONT CONTINUES TO LIFT THROUGH THE ALBEMARLE SOUND AND NORTHERN WATERS THIS AFTERNOON...WITH SLY WINDS GRADUALLY INCREASING. PRESSURE GRADIENT TIGHTENS QUICKLY THIS AFTERNOON AND TONIGHT WITH WARM FRONT TO THE NORTH AND APPROACHING COLD FRONT TO THE WEST. SLY WINDS WILL INCREASE TO 15-25KT WITH SEAS BUILDING TO 5-9FT. SCA HEADLINES CONTINUE FOR THE PAMLICO SOUND AND COASTAL WATERS. WINDS GRADUALLY DIMINISHING THROUGH THE DAY SUN...BY SUN AFTERNOON EXPECT SW WINDS 10-15KT THOUGH EXPECTED ELEVATED SEAS TO HANG TOUGH THROUGH THE PERIOD. LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 400 PM SATURDAY...EXPECTING HAZARDOUS CONDITIONS TO PREVAIL THROUGH MUCH OF THE PERIOD. STRONG NORTHERLY WINDS 20 TO 30 KT ARE FORECAST FROM SUNDAY NIGHT THROUGH MONDAY AS LOW PRESSURE TRACKS SOUTHEAST OF THE WATERS. COULD EVEN SEE A PERIOD OF GALES. CONDITIONS WILL GRADUALLY IMPROVE TUESDAY WITH CONDITIONS BRIEFLY DROPPING BELOW ADVISORY LEVELS TUESDAY NIGHT AND WEDNESDAY. ANOTHER LOW IS FORECAST TO MOVE SOUTHEAST OF THE WATERS WEDNESDAY NIGHT INTO THURSDAY WITH A RETURN TO ADVISORY CONDITIONS EXPECTED. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EST SUNDAY FOR AMZ135. SMALL CRAFT ADVISORY UNTIL 1 PM EST TUESDAY FOR AMZ152-154. SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR AMZ150-156-158. && $$ SYNOPSIS...CQD/HSA NEAR TERM...CQD SHORT TERM...CQD LONG TERM...JME AVIATION...JME/BTC MARINE...JME/CQD
AREA FORECAST DISCUSSION...COR SYN
NWS WILMINGTON NC
349 PM EST SAT FEB 21 2015 .SYNOPSIS... HIGH PRESSURE OFFSHORE WILL CIRCULATE MILD AIR INTO THE REGION WITH TEMPERATURES IN THE 60S SUNDAY. A GOOD CHANCE OF SIGNIFICANT RAIN IS EXPECTED SUNDAY NIGHT AND MONDAY...AS GULF MOISTURE IS LIFTED AHEAD OF AN UPPER TROUGH MOVING ACROSS THE EAST COAST. COLD AIR WILL RETURN LATE MONDAY AS ARCTIC HIGH PRESSURE BUILDS IN. COLD AND UNSETTLED WEATHER IS EXPECTED MUCH OF THE UPCOMING WEEK AS CHILLY HIGH PRESSURE AND GULF MOISTURE INTERACT. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 345 PM SATURDAY...FORECAST ON TRACK FOR A WARMING AND MOISTENING OF COLUMN THROUGH TONIGHT. TEMPS MADE IT UP INTO THE 50S MOST PLACES IN WAA IN INCREASING SE TO S LOW LEVEL WINDS. 850 TEMPS RISING FROM NEAR 0C THIS MORNING UP CLOSE TO 10C BY SUN MORNING IN ENHANCED RETURN FLOW AROUND HIGH PRESSURE AS IT SHIFTS FARTHER OFF SHORE. CLOUD COVER ASSOCIATED WITH CONVERGENCE ALONG COASTAL TROUGH THROUGH THE GRAND STRAND INTO WESTERN PORTIONS OF FORECAST AREA SPREADING NORTH REACHING ALL OF FORECAST AREA EARLY THIS AFTERNOON AS COASTAL TROUGH/WARM FRONT SHIFTS NORTH THROUGH THIS EVENING. COASTAL TROUGH QUITE EVIDENT IN OBS AND HIGHER RES MODELS WILL JOIN WITH WARM FRONT INLAND BLOWING NORTH THROUGH TONIGHT. LOOKS LIKE SOME LOW LEVEL CONVERGENCE AROUND RIDGE ALONG COASTAL TROUGH WILL CONTINUE TO BE FOCUS FOR CLOUDS AND PCP INTO THIS EVENING. LIFT WILL ALSO BE ENHANCED BY MINOR PERTURBATION PROGGED TO RIDE THROUGH EASTERN CAROLINAS THIS EVENING...INCREASING CHC OF SHOWERS MAINLY CLOSER TO THE COAST. ONCE THIS MOVES OFF SHORE AFTER MIDNIGHT...LOCAL AREA WILL REMAIN IN DEEP WARM AND MOIST S-SW FLOW...BUT SHOULD REMAIN BETWEEN SHWR ACTIVITY TO THE EAST OVER WATERS AND WELL WEST...ASSOCIATED WITH APPROACHING COLD FRONT. MAY EVEN END UP WITH SOME BREAKS IN CLOUD COVER OVERNIGHT. INCLUDED FOG AND SEA FOG AS WARM MOIST AIR RIDES ADVECTS OVER COLD WATERS AND OVER LAND. TEMPS OVERNIGHT WILL REMAIN WARM WITH MID 40S INLAND AND NEAR 50 CLOSER TO THE COAST. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...PRIMARY WEATHER HEADLINES SUNDAY AND MONDAY ARE PROSPECTS OF A DECENT SOAKER OF A RAIN EVENT SUNDAY NIGHT TO MONDAY MORNING...FOLLOWED BY A VERY SLIGHT CHANCE OF A FEW SNOW FLURRIES LATE ON MONDAY. GULF OF MEXICO TAP TO PLAY A NOTABLE ROLE IN ELEVATING DEEP COLUMN MOISTURE 18Z SUN-00Z TUE...WITH STORM TOTAL CALCULATIONS PROGGING ABOUT AN INCH OF RAINFALL ACROSS NE SC AND SE NC. THE BULK OF THIS APT TO FALL AS 6Z-18Z MONDAY AS INSENTROPIC OMEGA INCREASES. STRONG COLD AIR ADVECTION MONDAY AS HIGH PRESSURE OF ARCTIC BIRTH BARGES IN...WITH DIURNAL TEMPERATURE RANGES NARROW IN THE BATTLE WITH DAYTIME WARMING. VERY COLD AIR LATER IN THE DAY MONDAY AND NIGHT ON THE HEELS OF EGRESSING MOISTURE...COULD OPEN A WINDOW OF BRIEF SNOW FLURRIES. DEEP COLD CONVECTION UNLIKELY SINCE DRY AIR ENCROACHMENT ABOVE 850 MB WILL ALREADY BE UNDERWAY. MILDEST PERIOD SUNDAY AFTERNOON WITH 60S WIDESPREAD AWAY FROM THE IMMEDIATE BEACHES. COLDEST PERIOD EARLY TUES AS ARCTIC AIR SPILLS INTO THE CAROLINAS...MINIMUMS DAYBREAK TUESDAY 24-31 DEGREES. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 345 PM SATURDAY...SUBTLE PATTERN SHIFT THROUGH THE EXTENDED WILL LEAD TO CONTINUED COLD AIR ENTRENCHED ACROSS THE EAST...WITH THE SOUTHERN STREAM BECOMING THE DOMINANT WEATHER MAKER THROUGH THE WEEK. LONG-WAVE TROUGH WHICH HAS PLAGUED THE EASTERN CONUS FOR THE PAST MONTH WILL REMAIN...BUT IN A LESS AMPLIFIED SETUP. THE TROUGH WILL BROADEN SUCH THAT IT EXTENDS WELL INTO THE ATLANTIC...AND WHILE THIS WILL DO LITTLE TO REMEDY THE COLD...IT WILL KEEP MOST OF THE PRECIPITATION SUPPRESSED TO THE SOUTH. COLD FRONT WILL BE STALLED WELL SOUTH OF THE AREA TUESDAY MORNING...AND ALONG THIS BAROCLINIC GRADIENT IS WHERE A SERIES OF SHORTWAVES AND WEAK LOW PRESSURES WILL ROTATE THROUGH THE WEEK. THIS KEEPS AT LEAST A SCHC OF PRECIP...ESPECIALLY SE ZONES...THROUGH THE WEEK. TIMING OF THESE INDIVIDUAL SHORTWAVES AND SURFACE REFLECTIONS IS DIFFICULT...SO WILL MAKE LITTLE CHANGE TO INHERITED POP...AND KEEP A SCHC OF PRECIP ALONG THE COAST/SOUTH THROUGH THE WEEK. LOCAL TOP-DOWN METHODOLOGY DOES PRODUCE PERIODS OF R/S OR R/IP/ZR...PRETTY MUCH EACH DAY. CONFIDENCE IS LOW IN TIMING...AND TEMPS WILL WARM ABOVE FREEZING EACH AFTN SO HAVE OPTED TO KEEP ONLY LIQUID PRECIP FOR NOW THROUGH THURSDAY. HOWEVER...NEED TO MENTION THAT THERE VERY WELL COULD BE PERIODS OF WINTRY MIXED PRECIP...ALMOST ANY DAY THROUGH THE WEEK. TEMPS TUE-FRI WILL REMAIN WELL BELOW NORMAL FOR THE PERIOD...AVERAGING ABOUT 10 DEGREES BELOW CLIMO. LATE IN THE PERIOD THINGS GET A LITTLE MORE INTERESTING AS A STRONG SURFACE WEDGE RE-BUILDS DOWN THE COAST AHEAD OF A MORE SIGNIFICANT LOW PRESSURE SYSTEM. GUIDANCE AGREES THAT A COASTAL TROUGH WILL SHARPEN AND CLOSE OFF ON SATURDAY...BUT THE INTENSITY AND TRACK OF THE LOW IS STILL VERY MUCH IN QUESTION. WITH THE STRONG COLD WEDGE IN PLACE...WE COULD BE LOOKING AT A MIXED P-TYPE EVENT FRIDAY NIGHT INTO SATURDAY...BUT GUIDANCE DOES SHOW A QUICK WARMUP SATURDAY WHICH WOULD TRANSITION TO ALL RAIN. LOTS OF UNCERTAINTY AT THIS TIME RANGE...BUT THIS CONTINUES TO BE SUPPORTED BY GUIDANCE REGARDLESS OF THE STRICT PATTERN EVOLUTION. WITH TEMPS BELOW FREEZING AND CHC POP WARRANTED...AFTER COLLABORATION WITH NEIGHBORS HAVE OPTED TO INCLUDE THE ZR CREATED FROM TOP-DOWN FOR FRIDAY NIGHT INTO SATURDAY. STILL A LOT CAN CHANGE...BUT FRIDAY NIGHT INTO SATURDAY COULD GET MESSY ACROSS THE AREA. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... AS OF 21Z...SE WINDS ARE EXPECTED THIS AFTERNOON. AS COASTAL TROUGH PUSHES INLAND. ONLY MODERATE CONFIDENCE IN THE TIMING AND COVERAGE OF PRECIPITATION THIS AFTERNOON...INTO THE EVENING AND OVERNIGHT HOURS. THE HRRR AND THE NAM ARE IN REASONABLE AGREEMENT WITH A CONVERGENCE BOUNDARY OVER THE MYRTLES...REACHING ILM BY 20-22Z. MVFR CONDITIONS ARE EXPECTED IN THIS REGION...WITH POSSIBLE IFR CONDITIONS INLAND AS WARM SOUTHWEST FLOW RIDES OVER RELATIVELY COOLER SURFACE TEMPS. SUNDAY...LIGHT PRECIP WILL MOVE INTO THE WESTERN TERMINALS AS A COLD FRONT APPROACHES FROM THE WEST. THERE IS SOME DISAGREEMENT AMONG THE MODELS WITH RESPECT TO CEILINGS. WILL STAY RATHER PESSIMISTIC AT THIS TIME...KEEPING IFR INLAND. EXTENDED OUTLOOK...A SERIES OF WEAK SYSTEMS WILL MOVE THROUGH THE REGION THROUGH THE FORECAST PERIOD...WITH PERIODS OF LIGHT PRECIP POSSIBLE EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 345 PM FRIDAY...COASTAL TROUGH/WARM FRONT PROGRESSING INLAND THIS AFTERNOON LEAVING ON SHORE SOUTHEAST WINDS OVER THE WATERS. A PINCHED GRADIENT FROM COASTAL TROUGH WILL CONTINUE TO TIGHTEN BETWEEN HIGH PRESSURE OFF SHORE AND FRONTAL SYSTEM OVER THE CAROLINAS TO PRODUCE INCREASING WINDS THROUGH TONIGHT. WINDS WILL VEER FROM SE TO S ONCE THIS COASTAL TROUGH/WARM FRONT BLOWS NORTH OF THE AREA WATERS THROUGH TONIGHT. THE WARM AIR RUSHING OVER THE COOLER SHELF WATERS WILL KEEP MARINE LAYER MORE STABLE WITH STRONGER WINDS NOT MAKING IT DOWN TO WATER SFC CLOSER TO SHORE BUT AS YOU GO FARTHER OFF SHORE...SOUTHERLY WINDS WILL BE STRONGER AND GUSTIER PRODUCING CHOPPY AND HIGHER SEAS. OUTER WATERS WILL BE UP TO 5 TO 6 FT THROUGH TONIGHT. FRYING PAN BUOY MADE IT UP TO 7 FT THIS AFTN AND THEREFORE KEPT 6 FT ALONG OUTER FRINGE OF 20 NM MARK ALL WATERS UP UNTIL DAY BREAK AND INCLUDED FOR NORTHERN WATERS UP UNTIL 10 AM. HAVE ALSO INCLUDED SOME SEA FOG IN CONTINUED WAA. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...ADVISORIES MAY BE NEEDED EARLY SUNDAY AS SEA HEIGHTS RECOVER FROM THE PRESENT SE WAVE-BUILDING FETCH. AN ADVISORY WILL AGAIN BE NEEDED MOST IF NOT ALL OF MONDAY AS NORTH WINDS RIP ACROSS THE WATERS...DUE TO AN ARCTIC HIGH TAKEOVER. A WAVE DIRECTION TRANSITION TO BISECT THIS TIME PERIOD AS S WAVE ENERGY TURNS TO N AND NE MONDAY AND BUILDS WAVE-HEIGHTS AT TO ABOVE ADVISORY RANGE IN TANDEM WITH ADVISORY WINDS TO BOOT. NO TSTMS EXPECTED BUT PATCHY FOG WILL PLAGUE THE WATERS EARLY SUNDAY. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 345 PM SATURDAY...COLD FRONT WILL REMAIN STALLED JUST SOUTH OF THE WATERS THROUGH THE EXTENDED...WHILE WAVES OF LOW PRESSURE MOVE ALONG THIS BOUNDARY. THE PERIOD WILL BE BOOK-ENDED BY GUSTY N/NE WINDS BOTH EARLY TUESDAY AND AGAIN LATE THURSDAY...AS THE GRADIENT TIGHTENS NEAR LOW PRESSURE SYSTEMS MOVING WELL OFF THE COAST. SPEEDS DURING THESE NE SURGES WILL BE AROUND 15-20 KTS. WINDS EASE AND BACK TO THE NW TUESDAY NIGHT AND THROUGH WEDNESDAY AS HIGH PRESSURE RIDGES TOWARDS THE WATERS FROM THE NW...BEFORE AGAIN INCREASING LATE THURSDAY AS MENTIONED ABOVE. SEAS WILL BE 3-5 FT EARLY TUESDAY ON THE GUSTY NE WINDS...BEFORE EASING LATE TO 2-3 FT AND REMAINING AT THESE AMPLITUDES THROUGH WEDNESDAY NIGHT. AS THE WINDS RISE ON THURSDAY...SEAS BUILD AGAIN QUICKLY...AND AN EXTENDED PERIOD OF SCA CONDITIONS MAY DEVELOP BEGINNING THURSDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST SUNDAY FOR AMZ250-252-254- 256. && $$ SYNOPSIS...MJC NEAR TERM...RGZ SHORT TERM...MJC LONG TERM...JDW AVIATION...DL/RGZ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
330 PM EST SAT FEB 21 2015 .SYNOPSIS...A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AS AN UPPER LEVEL DISTURBANCE PASSES TO OUR NORTH. THE COLD FRONT WILL SETTLE SOUTH THROUGH THE AREA LATE SUNDAY AND THEN PUSH OFF THE SOUTHEAST COAST ON MONDAY. && .NEAR TERM /THROUGH SUNDAY NIGHT/... AS OF 330 PM SATURDAY... THE SHORTWAVE TROUGH CURRENTLY APPROACHING THE MID-MISSISSIPPI VALLEY REGION WILL LIFT THROUGH THE TENNESSEE AND OHIO VALLEYS TONIGHT. AT THE SURFACE...A RIDGE OF HIGH PRESSURE OVER CENTRAL NC WILL GIVE WAY TO SOUTHERLY FLOW AS THE ASSOCIATED COLD FRONT APPROACHES THE MOUNTAINS FROM THE WEST. LIGHT SNOW IN THE TRIAD EARLIER THIS MORNING YIELDED NO REPORTED ACCUMULATIONS AND HAS SINCE MOVED OFF TO THE NORTH. WARM ADVECTION CONTINUES TO STRENGTHEN OVER THE REGION AS AN INTENSE LOW-LEVEL JET (85KT AT BNA THIS MORNING) TRANSLATES EAST. TEMPERATURES HAVE BEEN RISING MUCH MORE QUICKLY IN THE SOUTHEAST SINCE NOON AS THE FLOW HAS BECOME SOUTHEASTERLY...REACHING THE MID-50S IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN. THERE IS ALSO SOME CLEARING ACROSS THE SOUTHERN PIEDMONT...WHICH MATCHES AN AREA OF DRYING NOTED IN RAP RH CROSS-SECTIONS. HOWEVER...MID AND HIGH LEVEL MOISTURE IS RAPIDLY SPREADING IN FROM THE WEST AND MOSTLY CLOUDY SKIES WILL THE RULE FOR MOST OF THE EVENING. THE FEW AREA OF WEAK RADAR ECHOES RACING NORTH/NORTHEAST ACROSS THE PIEDMONT AND COASTAL PLAIN ARE NOT AS ROBUST AS THE HI-RES MODELS HAD INDICATED...AT LEAST NOT SO FAR...POSSIBLY DUE TO THE AFOREMENTIONED DRYING. WILL MAINTAIN A SLIGHT CHANCE POP OF WHAT SHOULD BE RAIN FOR MOST AREAS AS THE WETBULB FREEZING LINE CONTINUES TO RETREAT NORTHWEST WITH THE WARMING/MOISTENING. THE EXCEPTION MAY BE THE NORTHERN PIEDMONT WHERE A POCKET OF SLEET MAY BE POSSIBLE IF PRECIP IS HEAVY ENOUGH...BUT CONFIDENCE IN THIS IS LOW AND THE IMPACTS WOULD BE NIL. THE MAIN OVERNIGHT CONCERNS WILL BE THE TIMING OF A PREFRONTAL RAINBAND ASSOCIATED WITH THE LOW-LEVEL JET AND ALSO THE POSSIBILITY OF FOG/LOW CLOUDS PRECEDING THE RAIN. FORECAST SOUNDINGS ARE IN GOOD AGREEMENT ON AT LEAST SOME STRATUS ASSOCIATED WITH THE STRONG WARM ADVECTION AND RISING DEWPOINTS. HOWEVER...PERIOD OF DRY AIR IN THE MID LEVELS MAY RESULT IN FOG EVEN DESPITE A STEADY SOUTHERLY WIND. THE PRIMARY AREA OF RAIN SHOULD ENTER THE NORTHWEST PIEDMONT SHORTLY AFTER MIDNIGHT AND TRANSLATE SOMEWHAT SLOWLY EAST THROUGH THE AREA THROUGH MIDDAY ON SUNDAY. WITH THE MAIN UPPER FORCING MOVING OFF TO THE NORTH AND THE LOW-LEVEL JET EXITING TO THE NORTHEAST...RAINFALL INTENSITY SHOULD ACCORDINGLY DECREASE WITH TIME SUNDAY MORNING. MODEL QPF SHOWS THIS TREND WITH A THIRD OF AN INCH NORTHWEST TO AROUND A TENTH IN THE SOUTHEAST. THE ACTUAL FRONT LOOKS TO BE DELAYED BY 3 TO 6 HOURS...FINALLY SETTLING SOUTH THROUGH THE AREA IN THE 21Z TO 03Z TIME FRAME. BUT... IT DOESNT STOP THERE AS MODELS SHOW A LOW-AMPLITUDE UPPER WAVE AND SPEED MAX TRANSLATING ACROSS THE GULF COAST STATES SUNDAY NIGHT...WHICH BRINGS ANAFRONTAL PRECIP BACK ACROSS AT LEAST THE SOUTHERN HALF OF NC AFTER MIDNIGHT SUNDAY NIGHT. THE POST-FRONTAL COLD ADVECTION WILL BE PUSHING TEMPS AND LOW-LEVEL THICKNESSES BACK DOWN TOWARD THE CRITICAL VALUES FOR SOME WINTRY MIX...BUT IT CURRENTLY LOOKS LIKE THIS WILL HOLD OFF UNTIL AFTER 12Z MONDAY (SEE MORE BELOW). THE GENERAL TREND FOR (FINALLY) ABOVE FREEZING TEMPS WILL BE TO RISE SLIGHTLY OR HOLD STEADY IN THE MID 30S NORTHWEST TO MID/UPPER 40S SOUTHEAST. HIGHS SUNDAY IN THE UPPER 40S TO MID 50S...FALLING INTO THE MID TO UPPER 30S MONDAY NIGHT. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 250 AM SATURDAY... SURFACE COLD FRONT WILL BE OFFSHORE MONDAY MORNING...WITH COLD HIGH PRESSURE BUILDING EAST ACROSS THE OHIO VALLEY AND SPILLING DOWN THE EAST COAST. THERE WILL BE A SMALL POTENTIAL FOR SOME LINGERING ANAFRONTAL LIGHT RAIN IN THE EAST MONDAY MORNING AS THE TRAILING H85 TROF MOVES ACROSS THE AREA. OTHERWISE...WILL LIKELY SEE SOME AFTERNOON SUN...ESPECIALLY ACROSS THE NORTHWEST...TO FEEBLY OFFSET STRENGTHENING COLD AIR ADVECTION. HIGHS WILL STRUGGLE TO REACH 40 ACROSS THE NORTH...WITH LOWER 40S ACROSS THE SOUTHERN TIER...A GOOD 15 DEGREES BELOW NORMAL. AXIS OF THE SURFACE HIGH WILL BE ALIGNED DOWN THE COAST MONDAY NIGHT...WITH MINS POTENTIALLY IN THE UPPER TEENS ACROSS THE NORTHERN TIER TO LOW 20S SOUTH. HIGHS TUESDAY WILL BE SIMILAR...PERHAPS EVEN A DEGREE OR TWO COOLER...THAN MONDAY UNDER THE HIGH PRESSURE...MOSTLY IN THE UPPER 30S. SURFACE HIGH SHIFTING OFFSHORE AND INCREASED MID CLOUDINESS AHEAD OF AN APPROACHING FRONT TUESDAY NIGHT WILL SOFTEN THE DIURNAL CRASH A BIT...WITH MINS IN THE LOW TO MID 20S. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 250 AM SATURDAY... ...WELL BELOW NORMAL TEMPERATURES WILL CONTINUE INTO THE WEEKEND... UPPER PATTERN WILL TRANSITION TO FLATTER...NEAR ZONAL FLOW ALOFT AS BROAD TROFFING SETS UP ACROSS THE NORTHERN CONUS THROUGH THE REMAINDER OF THE WEEK. THIS WILL EFFECTIVELY SUPPRESS MOISTURE TRANSPORT SOUTH ACROSS THE GULF STATES. IN THE ABSENCE OF COMPLEMENTARY SYNOPTIC SIGNALS IN THE LATEST MODEL RUNS...THIS PATTERN SUGGESTS MINIMAL PRECIP CHANCES THROUGH THE WEEK...AND WILL MAINTAIN ONGOING DRY FORECAST. WE WILL HAVE A REINFORCING COLD FRONT MOVE ACROSS ON WEDNESDAY...WITH BRIEF WARM AIR ADVECTION AHEAD OF THE FRONT BUMPING HIGHS UP A BIT INTO THE MID 40S. BEHIND THE FRONT...A SOUTHERN STREAM SHORT WAVE INDUCES CYCLOGENESIS ALONG THE FRONTAL BOUNDARY ACROSS NORTHERN FLORIDA WEDNESDAY NIGHT...AND THE LATEST ECMWF KEEPS THE LOW CLOSE ENOUGH TO THE COAST TO WRAP SOME PRECIP BACK INTO EASTERN NC...BUT WILL NEED TO SEE LATER MODEL CONSENSUS ON THIS SOLUTION BEFORE INTRODUCING POPS AT THIS POINT. THE UPSHOT...COLDER AIR RETURNS FOR LATE WEEK...WITH HIGHS BOTH THURSDAY AND FRIDAY IN THE UPPER 30S NORTH TO BARELY 40 ACROSS THE SOUTHERN TIER AFTER MORNING LOWS MOSTLY FROM 20 TO 25. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 105 PM SATURDAY... MVFR CEILINGS ARE LIKELY TO CONTINUE FOR MUCH OF THE AFTERNOON...THOUGH THERE IS SOME CLEARING ASSOCIATED WITH SOME DRIER LOW/MID LEVEL AIR OVER SC THAT IS CURRENTLY WORKING NORTH TOWARD THE SOUTHERN PIEDMONT. WHILE CONFIDENCE IS THE TIMING AND DURATION OF IMPROVED AND POSSIBLY VFR CEILINGS IS LOW...WILL SHOW SOME SCATTERING OF THE 1500-2500 FT CEILINGS CURRENTLY OBSERVED THROUGH 00Z. LATER THIS EVENING...CONTINUED WARM ADVECTION COMBINED WITH DRIER AIR ABOVE THE SURFACE MAY LEAD TO SOME FOG....MAINLY PRIOR TO MIDNIGHT BEFORE A BAND OF RAIN MOVES IN FROM THE NORTHWEST AHEAD OF AN APPROACHING COLD FRONT. CEILINGS WILL REMAIN LOW AS THE RAIN SPREADS ACROSS THE AREA...MOST LIKELY IN THE IFR RANGE. WINDS WILL REMAIN OUT OF THE SOUTH-SOUTHWEST OUTLOOK...THE COLD FRONT WILL SINK SOUTH THROUGH THE AREA LATE SUNDAY. SUB-VFR CEILINGS MAY LINGER BEHIND THE FRONT AS PRECIP SPREADS BACK ACROSS AT LEAST THE SOUTHERN PORTIONS OF NC LATER SUNDAY NIGHT INTO MONDAY. VFR CONDITIONS WILL RETURN BY TUESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLS NEAR TERM...BLS SHORT TERM...MLM LONG TERM...MLM AVIATION...BLS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
105 PM EST SAT FEB 21 2015 .SYNOPSIS...FRIGID HIGH PRESSURE WILL RETREAT OFF THE MID-ATLANTIC COAST TODAY. A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT... AND WILL MOVE THROUGH THE AREA ON SUNDAY. && .NEAR TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 1015 AM SATURDAY... SHORTWAVE TROUGH OVER THE CENTRAL PLAIN/MID MS VALLEY THIS MORNING WILL MOVE NEWD INTO THE OHIO VALLEY THIS AFTERNOON AND THEN INTO THE NEW ENGLAND TONIGHT. ASSOCIATED SFC WAVE AND FRONTAL ZONE WILL ADVANCE EAST INTO THE TN AND OHIO VALLEY TODAY...REACHING THE CENTRAL AND SOUTHERN APPALACHIANS AOA 12Z SUNDAY. MORNING UPDATE... RADAR ECHOES HAVE BEEN FILLING IN OVER THE FAR NORTHWEST PIEDMONT SINCE 12Z...THOUGH THE REFLECTIVITY VALUES ARE VERY WEAK AND KINT HAS ONLY REPORTED 9SM VISIBILITY THROUGHOUT THE LIGHT SNOW....SUGGESTING THE SNOW IS VERY LIGHT. RAP MOISTURE FIELDS SHOW A COUPLE MORE HOURS OF (NEAR) SATURATION ABOVE -10C AND A SLIGHTLY HEAVIER AREA OF SNOW LOOKS POISED TO POSSIBLY CLIP THE NORTHWESTERN HALF OF FORSYTH COUNTY. SO FAR THERE HAVE BEEN NO REPORTS OF ACCUMULATION...THOUGH A DUSTING CERTAINLY SEEMS POSSIBLE. HAVE ISSUED AN SPS TO HIGHLIGHT ANY LIGHT ACCUMULATION AND ISOLATED TRAVEL CONCERN...BUT WITHOUT GREATER RATES THIS DOESN`T WARRANT AN ADVISORY. DRYING IN THE MID-LEVELS CAUSE THE LIGHT SNOW TO END...POSSIBLY AS SLEET ON THE TAIL END...AND THEN NEARLY ALL GUIDANCE HAS THE WESTERN PIEDMONT DRY AFTER 18Z. TO THE EAST...MOISTURE ADVECTION FROM OFF THE SC COAST IS RAMPING UP...EVIDENT IN THE QUICK SURGE OF 2000-3000FT CEILINGS ACROSS THE SOUTHERN COASTAL PLAIN. AT THE SURFACE...THE RIDGE OF HIGH PRESSURE EXTENDING FROM THE OFF THE DELMARVA IS STILL HOLDING ON AND SURFACE WINDS HAVE YET TO REALLY TURN TO SOUTHEASTERLY. WITH TEMPS CURRENTLY IN THE UPPER 20S/ LOWER 30S AND DEWPOINTS STILL IN THE TEENS...THE WETBULB FREEZING LINE IS STILL SUPPRESSED TO THE COAST. HOWEVER... AS THE HIGH WEAKENS...WINDS ARE STILL FORECAST TO SHIFT AND DEWPOINTS SHOULD THEN RISE MORE DRAMATICALLY....CAUSING THE WETBULB FREEZING LINE TO QUICKLY RETREAT THROUGH THE PIEDMONT. HI- RES MODELS AND MAINLY NAM/GFS INDICATED SOME SHOWERY TYPE PRECIP BREAKING OUT ACROSS THE COASTAL PLAIN...BUT BY THEN WARMING WILL KEEP EVERYTHING LIQUID. NO MAJOR CHANGES TO THE FORECAST FOR THE EASTERN AREAS. HIGHS RANGING FROM THE MID 30S NORTHWEST TO AROUND 50 SOUTHEAST. -BLS TONIGHT THROUGH SUNDAY NIGHT: RAIN CHANCES WILL INCREASE AFTER MIDNIGHT AND INTO THE DAY ON SUNDAY OWING TO STRENGTHENING MOISTURE CONVERGENCE WITH THE APPROACH OF THE FRONT INTO THE AREA. PWATS INCREASE TO 1.0-1.25" WITH THE FRONT MOVING THROUGH THE AREA BETWEEN 12Z SUNDAY TO 00Z MONDAY. SOUNDINGS/THERMAL PROFILES SUPPORT ALL LIQUID WITH A SOLID BAND OF RAIN ACCOMPANYING THE FRONT INTO THE PIEDMONT BY THE MID TO LATE MORNING HOURS...THEN WEAKENING/FALLING APART AS IT REACHES THE COASTAL PLAIN AS DEEPER MOISTURE EXITS OFFSHORE WITH THE ATTENDANT LOW-LEVEL JET. RAIN CHANCES COULD LINGER IN THE WAKE OF THE FRONT SUNDAY NIGHT AND INTO MONDAY ACROSS THE FAR SOUTHERN ZONES AS THE H8 TROUGH IS SLOW TO CLEAR THE AREA. QPF AMOUNTS RANGING FROM A TENTH IN THE EAST TO A HALF INCH ACROSS THE WEST. LOWS SUNDAY NIGHT IN THE LOWER TO MID 30S NW TO MID/UPPER SE. HIGHS SUNDAY WILL DEPEND ON TIMING/COVERAGE OF PRECIP...RANGING FROM LOWER 50 NW TO UPPER 50S/NEAR 60 SE. CAA WILL GOVERN LOWS SUNDAY NIGHT... RANGING FROM NEAR 30 NORTH TO UPPER 30S SOUTH. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 250 AM SATURDAY... SURFACE COLD FRONT WILL BE OFFSHORE MONDAY MORNING...WITH COLD HIGH PRESSURE BUILDING EAST ACROSS THE OHIO VALLEY AND SPILLING DOWN THE EAST COAST. THERE WILL BE A SMALL POTENTIAL FOR SOME LINGERING ANAFRONTAL LIGHT RAIN IN THE EAST MONDAY MORNING AS THE TRAILING H85 TROF MOVES ACROSS THE AREA. OTHERWISE...WILL LIKELY SEE SOME AFTERNOON SUN...ESPECIALLY ACROSS THE NORTHWEST...TO FEEBLY OFFSET STRENGTHENING COLD AIR ADVECTION. HIGHS WILL STRUGGLE TO REACH 40 ACROSS THE NORTH...WITH LOWER 40S ACROSS THE SOUTHERN TIER...A GOOD 15 DEGREES BELOW NORMAL. AXIS OF THE SURFACE HIGH WILL BE ALIGNED DOWN THE COAST MONDAY NIGHT...WITH MINS POTENTIALLY IN THE UPPER TEENS ACROSS THE NORTHERN TIER TO LOW 20S SOUTH. HIGHS TUESDAY WILL BE SIMILAR...PERHAPS EVEN A DEGREE OR TWO COOLER...THAN MONDAY UNDER THE HIGH PRESSURE...MOSTLY IN THE UPPER 30S. SURFACE HIGH SHIFTING OFFSHORE AND INCREASED MID CLOUDINESS AHEAD OF AN APPROACHING FRONT TUESDAY NIGHT WILL SOFTEN THE DIURNAL CRASH A BIT...WITH MINS IN THE LOW TO MID 20S. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 250 AM SATURDAY... ...WELL BELOW NORMAL TEMPERATURES WILL CONTINUE INTO THE WEEKEND... UPPER PATTERN WILL TRANSITION TO FLATTER...NEAR ZONAL FLOW ALOFT AS BROAD TROFFING SETS UP ACROSS THE NORTHERN CONUS THROUGH THE REMAINDER OF THE WEEK. THIS WILL EFFECTIVELY SUPPRESS MOISTURE TRANSPORT SOUTH ACROSS THE GULF STATES. IN THE ABSENCE OF COMPLEMENTARY SYNOPTIC SIGNALS IN THE LATEST MODEL RUNS...THIS PATTERN SUGGESTS MINIMAL PRECIP CHANCES THROUGH THE WEEK...AND WILL MAINTAIN ONGOING DRY FORECAST. WE WILL HAVE A REINFORCING COLD FRONT MOVE ACROSS ON WEDNESDAY...WITH BRIEF WARM AIR ADVECTION AHEAD OF THE FRONT BUMPING HIGHS UP A BIT INTO THE MID 40S. BEHIND THE FRONT...A SOUTHERN STREAM SHORT WAVE INDUCES CYCLOGENESIS ALONG THE FRONTAL BOUNDARY ACROSS NORTHERN FLORIDA WEDNESDAY NIGHT...AND THE LATEST ECMWF KEEPS THE LOW CLOSE ENOUGH TO THE COAST TO WRAP SOME PRECIP BACK INTO EASTERN NC...BUT WILL NEED TO SEE LATER MODEL CONSENSUS ON THIS SOLUTION BEFORE INTRODUCING POPS AT THIS POINT. THE UPSHOT...COLDER AIR RETURNS FOR LATE WEEK...WITH HIGHS BOTH THURSDAY AND FRIDAY IN THE UPPER 30S NORTH TO BARELY 40 ACROSS THE SOUTHERN TIER AFTER MORNING LOWS MOSTLY FROM 20 TO 25. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 105 PM SATURDAY... MVFR CEILINGS ARE LIKELY TO CONTINUE FOR MUCH OF THE AFTERNOON...THOUGH THERE IS SOME CLEARING ASSOCIATED WITH SOME DRIER LOW/MID LEVEL AIR OVER SC THAT IS CURRENTLY WORKING NORTH TOWARD THE SOUTHERN PIEDMONT. WHILE CONFIDENCE IS THE TIMING AND DURATION OF IMPROVED AND POSSIBLY VFR CEILINGS IS LOW...WILL SHOW SOME SCATTERING OF THE 1500-2500 FT CEILINGS CURRENTLY OBSERVED THROUGH 00Z. LATER THIS EVENING...CONTINUED WARM ADVECTION COMBINED WITH DRIER AIR ABOVE THE SURFACE MAY LEAD TO SOME FOG....MAINLY PRIOR TO MIDNIGHT BEFORE A BAND OF RAIN MOVES IN FROM THE NORTHWEST AHEAD OF AN APPROACHING COLD FRONT. CEILINGS WILL REMAIN LOW AS THE RAIN SPREADS ACROSS THE AREA...MOST LIKELY IN THE IFR RANGE. WINDS WILL REMAIN OUT OF THE SOUTH-SOUTHWEST OUTLOOK...THE COLD FRONT WILL SINK SOUTH THROUGH THE AREA LATE SUNDAY. SUB-VFR CEILINGS MAY LINGER BEHIND THE FRONT AS PRECIP SPREADS BACK ACROSS AT LEAST THE SOUTHERN PORTIONS OF NC LATER SUNDAY NIGHT INTO MONDAY. VFR CONDITIONS WILL RETURN BY TUESDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL NEAR TERM...CBL/BLS SHORT TERM...MLM LONG TERM...MLM AVIATION...BLS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1243 PM EST SAT FEB 21 2015 .SYNOPSIS... SURFACE HIGH WILL PUSH FARTHER OFFSHORE TODAY WITH MILDER TEMPERATURES AND INCREASING RAIN CHANCES INTO SUNDAY AS COASTAL TROUGH MOVES NORTH AS WARM FRONT. A COLD FRONT WILL FOLLOW...MOVING THROUGH THE CAROLINAS SUNDAY NIGHT...STALLING ACROSS FLORIDA FOR THE REMAINDER OF NEXT WEEK. SEVERAL AREAS OF LOW PRESSURE ALONG THE FRONT MAY BRING UNSETTLED CONDITIONS NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1200 PM SATURDAY...FORECAST ON TRACK FOR A WARMING AND MOISTENING OF COLUMN THROUGH THE DAY. TEMPS ON THE RISE IN WAA IN INCREASING SE TO S LOW LEVEL WINDS. 850 TEMPS RISING FROM NEAR 0C THIS MORNING UP CLOSE TO 10C BY SUN MORNING IN ENHANCED RETURN FLOW AROUND HIGH PRESSURE AS IT SHIFTS FARTHER OFF SHORE. CLOUD COVER ASSOCIATED WITH CONVERGENCE ALONG COASTAL TROUGH THROUGH THE GRAND STRAND INTO WESTERN PORTIONS OF FORECAST AREA SPREADING NORTH REACHING ALL OF FORECAST AREA EARLY THIS AFTERNOON AS COASTAL TROUGH/WARM FRONT SHIFTS NORTH THROUGH THE DAY. TEMPS ACROSS SUNNIER SPOTS INCREASED A LITTLE FASTER THIS MORNING...BUT WAA WILL BRING MOST TEMPS UP CLOSE TO 50 INLAND AND MID 50S CLOSER TO THE COAST...BRINGING US OUT OF OUR COLD SNAP. RIGHT ALONG THE BEACHES TEMPS WILL BE LEVEL OFF AND FEEL COOLER COOL ON SHORE FLOW WITH COOLER OCEAN WATERS. COASTAL TROUGH QUITE EVIDENT IN OBS AND HIGHER RES MODELS WILL JOIN WITH WARM FRONT INLAND BLOWING NORTH THROUGH LATER TODAY INTO TONIGHT. LOOKS LIKE SOME LOW LEVEL CONVERGENCE AROUND RIDGE ALONG COASTAL TROUGH WILL CONTINUE TO BE FOCUS FOR CLOUDS AND PCP THIS AFTERNOON. LIFT WILL ALSO BE ENHANCED BY MINOR PERTURBATION PROGGED TO RIDE THROUGH EASTERN CAROLINAS THIS EVENING...WITH MORE CLOUDS AND SHOWERS EXPECTED. ONCE THIS MOVES OFF SHORE AFTER MIDNIGHT...LOCAL AREA WILL REMAIN IN DEEP WARM AND MOIST S-SW FLOW...BUT SHOULD REMAIN BETWEEN SHWR ACTIVITY TO THE EAST OVER WATERS AND WELL WEST...ASSOCIATED WITH APPROACHING COLD FRONT. MAY EVEN END UP WITH SOME MAINLY CLEAR AREAS OVERNIGHT. MAY HAVE TO EVALUATE FURTHER FOR POTENTIAL FOR FOG AND SEA FOG AS WARM MOIST AIR RIDES ADVECTS OVER COLD WATERS AND OVER LAND. TEMPS OVERNIGHT WILL REMAIN WARM WITH MID 40S INLAND AND NEAR 50 CLOSER TO THE COAST. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 AM SATURDAY...PERIOD BEGINS WITH WEAKLY FORCED COLD FRONT POISED TO ENTER THE AREA. LINE OF SHOWERS AHEAD OF THE FRONT WILL BE WEAKENING AS THEY REACH THE WESTERN EDGE OF THE FORECAST AREA. MID LEVEL SUPPORT WILL BE WANING AS THE SHORTWAVE RESPONSIBLE FOR THE ACTIVITY LIFTS OFF TO THE NORTHEAST. THERE WILL BE PLENTY OF MOISTURE AVAILABLE AND STRONG WARM ADVECTION AHEAD OF THE FRONT SHOULD PUSH TEMPS INTO THE 60S. THINK A BROKEN LINE OF SHOWERS WILL MOVE ACROSS THE AREA DURING EARLY TO MID AFTERNOON WITH THE BEST ACTIVITY/HIGHEST QPF ACROSS INLAND NC. MOST AREAS ARE LIKELY TO SEE AT LEAST SOME MEASURABLE PRECIP THOUGH THINK TOTAL RAINFALL WILL BE ON THE LOW END. SECOND ROUND OF PRECIP SUN NIGHT LOOKING MORE LIKELY. LACK OF STRONG MID LEVEL PUSH BEHIND THE FRONT LEAVES THE BOUNDARY STALLED CLOSE TO THE COAST. WEAK SURFACE WAVE AND MID LEVEL INFLECTION COINCIDENT WITH DEEP MOISTURE BRUSHES THE AREA AS IT LIFTS EAST-NORTHEAST SUN NIGHT. ALTHOUGH ISENTROPIC LIFT IS NOT MAXIMIZED THERE IS A PERIOD OF SOME ENHANCED LIFT ALONG WITH MID LEVEL DYNAMICS. INHERITED POP FORECAST INCLUDES A SOUTHEAST(HIGH) TO NORTHWEST(LOW) POP GRADIENT WHICH WILL BE MAINTAINED BUT WILL RAISE NUMBERS. PRECIP MAY LINGER INTO MON MORNING...ESPECIALLY ALONG THE COAST...BUT BY MIDDAY SUBSIDENCE IN THE WAKE OF THE EXITING SHORTWAVE ALONG WITH NEXT ARCTIC HIGH BUILDING IN FROM THE NORTHWEST WILL BRING AN END TO PRECIP IN THE REGION. AIR MASS IS NOT NEARLY AS COLD AS THE LAST FEW AND WHILE TEMPS WILL DROP BELOW NORMAL MON AND MON NIGHT ANOTHER EXTREME ARCTIC OUTBREAK DOES NOT LOOK TO BE IN THE CARDS. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 3 AM SATURDAY...LONG TERM PERIOD WILL BE UNSETTLED WITH ABUNDANT CLOUD COVER BUT LIMITED BOUTS OF MEASURABLE PRECIP. SURFACE HIGH REMAINS IN PLACE TUE WITH WEAK SHORTWAVE AND SURFACE INFLECTION PASSING OFF THE SOUTHEAST COAST. NOT EXPECTING A LOT OF PRECIP WITH THE FEATURE AS IT PASSES TO THE SOUTH BUT CLOUD COVER IS LIKELY. BRIEF PERIOD OF RETURN FLOW WED AHEAD OF NEXT COLD FRONT WILL HAVE LIMITED SUCCESS IN WARMING TEMPS. WED SHOULD BE THE WARMEST DAY OF THE PERIOD BUT HIGHS WILL STILL BE 10+ DEGREES BELOW CLIMO. FRONT WILL BE IN THE PROCESS OF WASHING OUT AS IT REACHES THE AREA AND DESPITE ABUNDANT MOISTURE THERE IS A NOTICEABLE LACK OF FORCING WITH THE FRONT. CANNOT RULE OUT SOME ISOLATED SPRINKLES BUT MEASURABLE RAIN SEEMS UNLIKELY. SOUTHERN STREAM SYSTEM EMERGING FROM THE SOUTHWEST WED WILL MOVE EAST ALONG THE STALLED BOUNDARY...PASSING JUST OFF THE SOUTHEAST COAST THU INTO FRI. CONFIDENCE IN THE EXISTENCE OF THIS SYSTEM IS ABOVE AVERAGE BUT ITS PROXIMITY TO THE REGION AS IT PASSES IS A BIG QUESTION. THE GFS IS FAVORING A MORE SOUTHERLY/OFFSHORE TRACK WHILE THE ECMWF IS A LITTLE FARTHER NORTH AND CLOSER TO THE SOUTHEAST COAST. THIS IS DOWN TO THE HANDLING OF THE SOUTHERN STREAM SHORTWAVE...SOMETHING WHICH WILL BE FLESHED OUT EARLY NEXT WEEK AS THE INCOMING SHORTWAVE RESPONSIBLE FOR KICKING THE SOUTHERN STREAM SYSTEM OUT OF THE SOUTHWEST MOVES INTO THE UPPER AIR NETWORK. FOR NOW WILL CONTINUE WITH INHERITED SILENT POP. ALTHOUGH HARD TO SAY AT THIS POINT IT WOULD APPEAR P TYPE ISSUES MAY NOT BE A PROBLEM LATE IN THE PERIOD. IF THE ECMWF IS CORRECT AND THE SYSTEM IS CLOSER TO THE COAST THEN TEMPS WOULD LIKELY BE TOO WARM. ALTERNATIVELY IF THE GFS IS CORRECT AIR MASS MAY BE COLD ENOUGH FOR FROZEN PRECIP BUT THE PRECIP WOULD REMAIN OFFSHORE. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 18Z...SE WINDS ARE EXPECTED THIS AFTERNOON. AS COASTAL TROUGH PUSHES INLAND. ONLY MODERATE CONFIDENCE IN THE TIMING AND COVERAGE OF PRECIPITATION THIS AFTERNOON...INTO THE EVENING AND OVERNIGHT HOURS. THE HRRR AND THE NAM ARE IN REASONABLE AGREEMENT WITH A CONVERGENCE BOUNDARY OVER THE MYRTLES...REACHING ILM BY 20-22Z. MVFR CONDITIONS ARE EXPECTED IN THIS REGION...WITH POSSIBLE IFR CONDITIONS INLAND AS WARM SOUTHWEST FLOW RIDES OVER RELATIVELY COOLER SURFACE TEMPS. SUNDAY...LIGHT PRECIP WILL MOVE INTO THE WESTERN TERMINALS AS A COLD FRONT APPROACHES FROM THE WEST. THERE IS SOME DISAGREEMENT AMONG THE MODELS WITH RESPECT TO CEILINGS. WILL STAY RATHER PESSIMISTIC AT THIS TIME...KEEPING IFR INLAND. EXTENDED OUTLOOK...A SERIES OF WEAK SYSTEMS WILL MOVE THROUGH THE REGION THROUGH THE FORECAST PERIOD...WITH PERIODS OF LIGHT PRECIP POSSIBLE EACH DAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1200 PM FRIDAY...COASTAL TROUGH RUNNING UP FROM SOUTH CAROLINA WATERS INTO THE CAPE FEAR COAST WILL PRODUCE SE WINDS THROUGH TODAY. A PINCHED GRADIENT FROM COASTAL TROUGH WILL CONTINUE TO TIGHTEN BETWEEN HIGH PRESSURE OFF SHORE AND FRONTAL SYSTEM OVER THE CAROLINAS TO PRODUCE INCREASING WINDS THROUGH TONIGHT. WINDS WILL VEER FROM SE TO S ONCE THIS COASTAL TROUGH/WARM FRONT BLOWS NORTH OF THE AREA WATERS THROUGH TONIGHT. THE WARM AIR RUSHING OVER THE COOLER SHELF WATERS WILL KEEP MARINE LAYER MORE STABLE WITH STRONGER WINDS NOT MAKING IT DOWN TO WATER SFC BUT AS YOU GO FARTHER OFF SHORE...SOUTHERLY WINDS WILL BE STRONGER AND GUSTIER PRODUCING CHOPPY AND HIGHER SEAS. OUTER WATERS SHOULD REACH UP 4 TO 5 FT LATER TODAY AND TONIGHT LEAVING SCA CONDITIONS BEYOND THE 20 NM RANGE. KEPT FORECAST SEAS ON TRACK AND SLIGHTLY LOWER THAN WAVEWATCH3 AND SWAN MODELS DUE TO THE DIFFICULTY OF THE STRONGER WAA WINDS ALOFT MIXING DOWN TO THE OCEAN SFC WHERE SSTS ARE IN THE 40S. WILL NEED TO EXAMINE POTENTIAL FOR ANY SEA FOG AS TEMPS AND DEWPOINTS WARM THROUGH THE NIGHT. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 AM SATURDAY...SOUTHWEST FLOW AHEAD OF ADVANCING COLD FRONT SUN WILL BE 10 TO 15 KT FOR MUCH OF THE DAY BEFORE DROPPING UNDER 10 KT AS THE FRONT ARRIVES LATE. NORTHERLY DEVELOPS BEHIND THE FRONT WITH GRADIENT BECOMING PINCHED AFTER MIDNIGHT. COMBINATION OF TIGHT GRADIENT AND COLD SURGE BEHIND THE FRONT WILL PUSH WIND SPEEDS INTO THE 20 TO 25 KT RANGE MON AND MON NIGHT. SEAS RUNNING 3 TO 5 FT AT THE START OF THE PERIOD BUILD TO 4 TO 7 FT MON INTO MON NIGHT. LONG TERM /TUESDAY THROUGH WEDNESDAY/... AS OF 3 AM SATURDAY...PINCHED GRADIENT TUE MORNING WILL WEAKEN DURING THE DAY AS SURFACE HIGH SLIDES EAST...DROPPING NORTHEAST FLOW FROM 15 TO 20 KT TUE MORNING TO UNDER 10 KT BY AFTERNOON. SURFACE RIDGE AXIS SHIFTS OFFSHORE TUE NIGHT WITH A BRIEF PERIOD OF WEST- SOUTHWEST FLOW SETTING UP WED AHEAD OF THE NEXT COLD FRONT. INITIALLY FRONT LACKS COLD ADVECTION OR A GRADIENT BUT NORTHERLY FLOW WILL START INCREASING LATE IN THE PERIOD. GRADIENT WILL BECOME MORE DEFINED IN RESPONSE TO SYSTEM EMERGING FROM THE GULF OF MEXICO...INCREASING NORTHEAST FLOW. SEAS 3 TO 5 FT TUE DROP TO 2 TO 4 FT TUE NIGHT AND WED THEN BUILD TO 3 TO 5 FT LATE IN THE PERIOD. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RGZ SHORT TERM...III LONG TERM...III AVIATION...DL/RGZ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1015 AM EST SAT FEB 21 2015 .SYNOPSIS...FRIGID HIGH PRESSURE WILL RETREAT OFF THE MID-ATLANTIC COAST TODAY. A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT... AND WILL MOVE THROUGH THE AREA ON SUNDAY. && .NEAR TERM /SATURDAY THROUGH SUNDAY NIGHT/... AS OF 1015 AM SATURDAY... SHORTWAVE TROUGH OVER THE CENTRAL PLAIN/MID MS VALLEY THIS MORNING WILL MOVE NEWD INTO THE OHIO VALLEY THIS AFTERNOON AND THEN INTO THE NEW ENGLAND TONIGHT. ASSOCIATED SFC WAVE AND FRONTAL ZONE WILL ADVANCE EAST INTO THE TN AND OHIO VALLEY TODAY...REACHING THE CENTRAL AND SOUTHERN APPALACHIANS AOA 12Z SUNDAY. MORNING UPDATE... RADAR ECHOES HAVE BEEN FILLING IN OVER THE FAR NORTHWEST PIEDMONT SINCE 12Z...THOUGH THE REFLECTIVITY VALUES ARE VERY WEAK AND KINT HAS ONLY REPORTED 9SM VISBILITY THROUGHOUT THE LIGHT SNOW....SUGGESTING THE SNOW IS VERY LIGHT. RAP MOISTURE FIELDS SHOW A COUPLE MORE HOURS OF (NEAR) SATURATION ABOVE -10C AND A SLIGHTLY HEAVIER AREA OF SNOW LOOKS POISED TO POSSIBLY CLIP THE NORTHWESTERN HALF OF FORSYTH COUNTY. SO FAR THERE HAVE BEEN NO REPORTS OF ACCUMULATION...THOUGH A DUSTING CERTAINLY SEEMS POSSIBLE. HAVE ISSUED AN SPS TO HIGHLIGHT ANY LIGHT ACCUMULATION AND ISOLATED TRAVEL CONCERN...BUT WITHOUT GREATER RATES THIS DOESN`T WARRANT AN ADVISORY. DRYING IN THE MID-LEVELS CAUSE THE LIGHT SNOW TO END...POSSIBLY AS SLEET ON THE TAIL END...AND THEN NEARLY ALL GUIDANCE HAS THE WESTERN PIEDMONT DRY AFTER 18Z. TO THE EAST...MOISTURE ADVECTION FROM OFF THE SC COAST IS RAMPING UP...EVIDENT IN THE QUICK SURGE OF 2000-3000FT CEILINGS ACROSS THE SOUTHERN COASTAL PLAIN. AT THE SURFACE...THE RIDGE OF HIGH PRESSURE EXTENDING FROM THE OFF THE DELMARVA IS STILL HOLDING ON AND SURFACE WINDS HAVE YET TO REALLY TURN TO SOUTHEASTERLY. WITH TEMPS CURRENTLY IN THE UPPER 20S/ LOWER 30S AND DEWPOINTS STILL IN THE TEENS...THE WETBULB FREEZING LINE IS STILL SUPPRESSED TO THE COAST. HOWEVER... AS THE HIGH WEAKENS...WINDS ARE STILL FORECAST TO SHIFT AND DEWPOINTS SHOULD THEN RISE MORE DRAMATICALLY....CAUSING THE WETBULB FREEZING LINE TO QUICKLY RETREAT THROUGH THE PIEDMONT. HI- RES MODELS AND MAINLY NAM/GFS INDICATED SOME SHOWERY TYPE PRECIP BREAKING OUT ACROSS THE COASTAL PLAIN...BUT BY THEN WARMING WILL KEEP EVERYTHING LIQUID. NO MAJOR CHANGES TO THE FORECAST FOR THE EASTERN AREAS. HIGHS RANGING FROM THE MID 30S NORTHWEST TO AROUND 50 SOUTHEAST. -BLS TONIGHT THROUGH SUNDAY NIGHT: RAIN CHANCES WILL INCREASE AFTER MIDNIGHT AND INTO THE DAY ON SUNDAY OWING TO STRENGTHENING MOISTURE CONVERGENCE WITH THE APPROACH OF THE FRONT INTO THE AREA. PWATS INCREASE TO 1.0-1.25" WITH THE FRONT MOVING THROUGH THE AREA BETWEEN 12Z SUNDAY TO 00Z MONDAY. SOUNDINGS/THERMAL PROFILES SUPPORT ALL LIQUID WITH A SOLID BAND OF RAIN ACCOMPANYING THE FRONT INTO THE PIEDMONT BY THE MID TO LATE MORNING HOURS...THEN WEAKENING/FALLING APART AS IT REACHES THE COASTAL PLAIN AS DEEPER MOISTURE EXITS OFFSHORE WITH THE ATTENDANT LOW-LEVEL JET. RAIN CHANCES COULD LINGER IN THE WAKE OF THE FRONT SUNDAY NIGHT AND INTO MONDAY ACROSS THE FAR SOUTHERN ZONES AS THE H8 TROUGH IS SLOW TO CLEAR THE AREA. QPF AMOUNTS RANGING FROM A TENTH IN THE EAST TO A HALF INCH ACROSS THE WEST. LOWS SUNDAY NIGHT IN THE LOWER TO MID 30S NW TO MID/UPPER SE. HIGHS SUNDAY WILL DEPEND ON TIMING/COVERAGE OF PRECIP...RANGING FROM LOWER 50 NW TO UPPER 50S/NEAR 60 SE. CAA WILL GOVERN LOWS SUNDAY NIGHT... RANGING FROM NEAR 30 NORTH TO UPPER 30S SOUTH. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 250 AM SATURDAY... SURFACE COLD FRONT WILL BE OFFSHORE MONDAY MORNING...WITH COLD HIGH PRESSURE BUILDING EAST ACROSS THE OHIO VALLEY AND SPILLING DOWN THE EAST COAST. THERE WILL BE A SMALL POTENTIAL FOR SOME LINGERING ANAFRONTAL LIGHT RAIN IN THE EAST MONDAY MORNING AS THE TRAILING H85 TROF MOVES ACROSS THE AREA. OTHERWISE...WILL LIKELY SEE SOME AFTERNOON SUN...ESPECIALLY ACROSS THE NORTHWEST...TO FEEBLY OFFSET STRENGTHENING COLD AIR ADVECTION. HIGHS WILL STRUGGLE TO REACH 40 ACROSS THE NORTH...WITH LOWER 40S ACROSS THE SOUTHERN TIER...A GOOD 15 DEGREES BELOW NORMAL. AXIS OF THE SURFACE HIGH WILL BE ALIGNED DOWN THE COAST MONDAY NIGHT...WITH MINS POTENTIALLY IN THE UPPER TEENS ACROSS THE NORTHERN TIER TO LOW 20S SOUTH. HIGHS TUESDAY WILL BE SIMILAR...PERHAPS EVEN A DEGREE OR TWO COOLER...THAN MONDAY UNDER THE HIGH PRESSURE...MOSTLY IN THE UPPER 30S. SURFACE HIGH SHIFTING OFFSHORE AND INCREASED MID CLOUDINESS AHEAD OF AN APPROACHING FRONT TUESDAY NIGHT WILL SOFTEN THE DIURNAL CRASH A BIT...WITH MINS IN THE LOW TO MID 20S. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 250 AM SATURDAY... ...WELL BELOW NORMAL TEMPERATURES WILL CONTINUE INTO THE WEEKEND... UPPER PATTERN WILL TRANSITION TO FLATTER...NEAR ZONAL FLOW ALOFT AS BROAD TROFFING SETS UP ACROSS THE NORTHERN CONUS THROUGH THE REMAINDER OF THE WEEK. THIS WILL EFFECTIVELY SUPPRESS MOISTURE TRANSPORT SOUTH ACROSS THE GULF STATES. IN THE ABSENCE OF COMPLEMENTARY SYNOPTIC SIGNALS IN THE LATEST MODEL RUNS...THIS PATTERN SUGGESTS MINIMAL PRECIP CHANCES THROUGH THE WEEK...AND WILL MAINTAIN ONGOING DRY FORECAST. WE WILL HAVE A REINFORCING COLD FRONT MOVE ACROSS ON WEDNESDAY...WITH BRIEF WARM AIR ADVECTION AHEAD OF THE FRONT BUMPING HIGHS UP A BIT INTO THE MID 40S. BEHIND THE FRONT...A SOUTHERN STREAM SHORT WAVE INDUCES CYCLOGENESIS ALONG THE FRONTAL BOUNDARY ACROSS NORTHERN FLORIDA WEDNESDAY NIGHT...AND THE LATEST ECMWF KEEPS THE LOW CLOSE ENOUGH TO THE COAST TO WRAP SOME PRECIP BACK INTO EASTERN NC...BUT WILL NEED TO SEE LATER MODEL CONSENSUS ON THIS SOLUTION BEFORE INTRODUCING POPS AT THIS POINT. THE UPSHOT...COLDER AIR RETURNS FOR LATE WEEK...WITH HIGHS BOTH THURSDAY AND FRIDAY IN THE UPPER 30S NORTH TO BARELY 40 ACROSS THE SOUTHERN TIER AFTER MORNING LOWS MOSTLY FROM 20 TO 25. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 645 AM SATURDAY... 24 HOUR TAF PERIOD: MOISTURE WILL BE ON THE INCREASE AS HIGH PRESSURE MOVES FURTHER OFFSHORE AND SOUTHERLY FLOW DEEPENS AHEAD OF A COLD FRONT WHICH WILL MOVE ACROSS THE AREA AROUND MID DAY ON SUNDAY. HAVE SEEN SOME PATCHY -SN APPROACHING GSO/INT WITH CEILINGS FALLING OVERNIGHT TO AROUND 4K FEET IN THE WEST AND SOUTH. EXPECT MVFR CEILINGS AT GSO/INT AROUND 15Z WITH PATCHY PREFRONTAL LIGHT RAIN AND/OR SNOW INTO EARLY AFTERNOON. RAIN IS EXPECTED TO SURGE NORTH INTO CENTRAL NC THIS MORNING...WITH CEILINGS FALLING TO MVFR AROUND 18Z WITH PATCHY R- AT THE EASTERN TAF SITES FROM 18-22Z. WARM AND MOIST SOUTHERLY FLOW WILL CONTINUE WITH TEMPERATURES RISING OVERNIGHT. MVFR CEILINGS AND POSSIBLY VISIBILITIES ARE EXPECTED AT ALL SITES OVERNIGHT WITH HEAVIER RAIN SPREADING EAST ACROSS THE AREA...INTO THE WEST AROUND 06Z...AND INTO THE EAST BY 09Z. CEILINGS WILL FALL TO IFR WITH THE RAIN SHIELD...WITH CONDITIONS CONTINUING INTO SUNDAY AFTERNOON. OUTLOOK: APPROACHING COLD FRONT AND ASSOCIATED RAIN AND SUB-VFR CONDITIONS WILL CONTINUE TO IMPACT THE AREA SUNDAY AFTERNOON... PERHAPS LINGERING WELL INTO THE OVERNIGHT AS DRYING WILL BE SLOW TO ENSUE...EVEN AS WINDS SHIFT AROUND TO NORTHERLY SUNDAY EVENING 00Z. VFR CONDITIONS WILL BE PREVALENT TUE AND WED. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL NEAR TERM...CBL/BLS SHORT TERM...MLM LONG TERM...MLM AVIATION...MLM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1253 PM EST SAT FEB 21 2015 .SYNOPSIS... LOW PRESSURE SYSTEM BRINGS WINTRY MIX TONIGHT THROUGH SATURDAY NIGHT. COLD AGAIN FOR THE END OF THE WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... FORECAST ON TRACK WITH NO CHANGES PLANNED. WE ARE SEEING A SMORGASBORD WINTRY PRECIPITATION ACROSS THE CWA. IN A NUTSHELL... WHEREVER WE ARE SEEING STRONG DYNAMIC LIFT ACROSS THE SOUTHERN HALF OF THE CWA THERE IS SNOW IS FALLING...EVEN AS TEMPS ARE ABOVE FREEZING. DYNAMIC COOLING ALOFT HELPING TO OFFSET WARM AIR INTRUSION IN THESE AREAS. OTHERWISE...FREEZING RAIN RULES THE ROOST IN THE SOUTH. ACROSS THE NORTHERN HALF OF THE CWA...WE ARE SEEING MAINLY SNOW WHERE THE COLD AIR DOME IS MORE FIRMLY ENTRENCHED. HRRR SEEMS TO HAVE A DECENT HANDLE ON AMOUNT OF WARMING TO OCCUR FROM WARM AIR INTRUSION ALOFT AND WE ARE GOING TO STICK TO ITS TRENDS IN THE NEAR TERM. STARTING AT ABOUT 19Z WE SHOULD SEE TRANSITION FROM SOUTH TO NORTH THAT CHANGES US TO AN ALL RAIN IN THE WX GRIDS...THE EXCEPTION BEING SE OH AND THE EASTERN MOUNTAINS OF NE WV WHERE SUB FREEZING TEMPS REMAIN AT ALL LEVELS. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... A BRIEF PERIOD OF UPSLOPE ENDS THE LOW PRESSURE SYSTEM EVENT FOR THE CENTRAL APPALACHIANS SUNDAY WITH THE LAST OF THE FLAKES FALLING EARLY SUNDAY NIGHT. A RETURN TO THE ARCTIC AIR...NOT AS JARRING AS THE LAST ONE...FOLLOWS FOR THE BEGINNING OF THE WORK WEEK. HIGH PRESSURE BRINGS A DRY PERIOD THROUGH THE REMAINDER OF THE SHORT TERM...WITH MODELS CLEARING THE SKY MONDAY NIGHT. CENTER OF HIGH PRESSURE WILL BE JUST TO THE SOUTHWEST...SO DECOUPLING LIKELY WITH ANOTHER GOOD RADIATIONAL COOLING NIGHT. TAKING THE CONSERVATIVE APPROACH FOR NOW...BUT IF THE MODEL SOLUTIONS HOLD AND SNOW REMAINS ON THE GROUND DESPITE THE WET FORECAST TODAY IN PLACES...MAY NEED TO LOWER THESE TEMPERATURES. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... OVERALL NOTHING TOO SIGNIFICANT IN THE LONG TERM...ALTHOUGH IT WILL CONTINUE TO BE COLD WITH PERIODS OF LIGHT SNOW SHOWERS AT TIMES. NORTHWESTERLY FLOW TO START THE PERIOD...WITH THE POSSIBILITY OF SOME LIGHT SNOW SHOWERS LINGERING MONDAY NIGHT INTO EARLY TUESDAY. THESE WILL TAPER OFF HOWEVER AS HIGH PRESSURE BUILDS IN FROM THE WEST. MID WEEK BECOMES A LITTLE MORE UNCERTAIN. CHANCES LOOK GOOD FOR A CLIPPER TYPE SYSTEM TO AFFECT THE AREA MID WEEK...BRINGING SOME LIGHT SNOW SHOWERS...BUT SOME UNCERTAINTY AS TO WHETHER MOISTURE FROM A SYSTEM TO THE SOUTH WILL BE ABLE TO WORK ITS WAY INTO THE AREA. FOR NOW...MAINTAINED SLIGHT CHANCE TO CHANCE POPS MID WEEK TO ACCOUNT FOR THESE VARIABLES...AND BROAD BRUSHED THE PERIOD. TEMPS LOOK TO REMAIN BELOW NORMAL FOR THE PERIOD. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... GENERALLY IFR/LIFR AREA WIDE THROUGH THE PERIOD. SLOW TO IMPROVE CONDITIONS LATE TONIGHT CAUSE THINK THAT FOG WILL SETTLE IN ACROSS LEFTOVER SNOWPACK AS WARM AND MOIST AIR ROLLS ON IN THIS EVENING. LATE IN THE PERIOD...WE BRING IN A HINT OF IMPROVEMENT AS COLD FRONT CROSS FROM WEST TO EAST TO HELP SCOUR OUT FOG. FOR THE REMAINDER OF TODAY...SITES CONTINUE TO SEE A TRANSITION FROM FREEZING PRECIPITATION TO MOSTLY RAIN...REACHING KEKN BY AROUND 01Z THIS EVENING. GUSTY SOUTHERLY WINDS TO 30 MPH ON MOUNTAIN RIDGE TOPS INVOF OF 85H LLJ TRANSITIONING ACROSS CWA. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: LOW...ESPECIALLY WITH TIMING OF AND TRANSITION TO MIXED PRECIP AND ANY FOG DEVELOPMENT. ALTERNATE SCENARIOS: LARGE VARIABILITY IN PRECIP TYPE AND TIMING...ESPECIALLY CENTRAL AND NORTH. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EST 1HRLY 13 14 15 16 17 18 19 20 21 22 23 00 CRW CONSISTENCY L H H H H H H H H H L L HTS CONSISTENCY M M M L M M H L L L L L BKW CONSISTENCY L M M M M M H M M L M L EKN CONSISTENCY M M M L H H H H H M H M PKB CONSISTENCY L M M H H H H H M M M L CKB CONSISTENCY L M M H H H M H H H H M AFTER 18Z SUNDAY... IFR IN WINTRY PRECIP ACROSS MOUNTAIN SITES SUNDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR WVZ007>011-014>020-027>032-035>040. WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR WVZ005- 006-013-024>026-033-034. WINTER STORM WARNING UNTIL 4 AM EST SUNDAY FOR WVZ046-047. OH...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR OHZ066- 067-075-076-083>086. WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR OHZ087. KY...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR KYZ101>103-105. VA...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR VAZ003- 004. && $$ SYNOPSIS...JMV/26 NEAR TERM...KMC SHORT TERM...26 LONG TERM...SL AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
937 AM EST SAT FEB 21 2015 .SYNOPSIS... LOW PRESSURE SYSTEM BRINGS WINTRY MIX TONIGHT THROUGH SATURDAY NIGHT. COLD AGAIN FOR THE END OF THE WEEKEND AND EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... FORECAST ON TRACK WITH NO CHANGES PLANNED. WE ARE SEEING A SMORGASBORD WINTRY PRECIPITATION ACROSS THE CWA. IN A NUTSHELL... WHEREVER WE ARE SEEING STRONG DYNAMIC LIFT ACROSS THE SOUTHERN HALF OF THE CWA THERE IS SNOW IS FALLING...EVEN AS TEMPS ARE ABOVE FREEZING. DYNAMIC COOLING ALOFT HELPING TO OFFSET WARM AIR INTRUSION IN THESE AREAS. OTHERWISE...FREEZING RAIN RULES THE ROOST IN THE SOUTH. ACROSS THE NORTHERN HALF OF THE CWA...WE ARE SEEING MAINLY SNOW WHERE THE COLD AIR DOME IS MORE FIRMLY ENTRENCHED. HRRR SEEMS TO HAVE A DECENT HANDLE ON AMOUNT OF WARMING TO OCCUR FROM WARM AIR INTRUSION ALOFT AND WE ARE GOING TO STICK TO ITS TRENDS IN THE NEAR TERM. STARTING AT ABOUT 19Z WE SHOULD SEE TRANSITION FROM SOUTH TO NORTH THAT CHANGES US TO AN ALL RAIN IN THE WX GRIDS...THE EXCEPTION BEING SE OH AND THE EASTERN MOUNTAINS OF NE WV WHERE SUB FREEZING TEMPS REMAIN AT ALL LEVELS. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... A BRIEF PERIOD OF UPSLOPE ENDS THE LOW PRESSURE SYSTEM EVENT FOR THE CENTRAL APPALACHIANS SUNDAY WITH THE LAST OF THE FLAKES FALLING EARLY SUNDAY NIGHT. A RETURN TO THE ARCTIC AIR...NOT AS JARRING AS THE LAST ONE...FOLLOWS FOR THE BEGINNING OF THE WORK WEEK. HIGH PRESSURE BRINGS A DRY PERIOD THROUGH THE REMAINDER OF THE SHORT TERM...WITH MODELS CLEARING THE SKY MONDAY NIGHT. CENTER OF HIGH PRESSURE WILL BE JUST TO THE SOUTHWEST...SO DECOUPLING LIKELY WITH ANOTHER GOOD RADIATIONAL COOLING NIGHT. TAKING THE CONSERVATIVE APPROACH FOR NOW...BUT IF THE MODEL SOLUTIONS HOLD AND SNOW REMAINS ON THE GROUND DESPITE THE WET FORECAST TODAY IN PLACES...MAY NEED TO LOWER THESE TEMPERATURES. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... OVERALL NOTHING TOO SIGNIFICANT IN THE LONG TERM...ALTHOUGH IT WILL CONTINUE TO BE COLD WITH PERIODS OF LIGHT SNOW SHOWERS AT TIMES. NORTHWESTERLY FLOW TO START THE PERIOD...WITH THE POSSIBILITY OF SOME LIGHT SNOW SHOWERS LINGERING MONDAY NIGHT INTO EARLY TUESDAY. THESE WILL TAPER OFF HOWEVER AS HIGH PRESSURE BUILDS IN FROM THE WEST. MID WEEK BECOMES A LITTLE MORE UNCERTAIN. CHANCES LOOK GOOD FOR A CLIPPER TYPE SYSTEM TO AFFECT THE AREA MID WEEK...BRINGING SOME LIGHT SNOW SHOWERS...BUT SOME UNCERTAINTY AS TO WHETHER MOISTURE FROM A SYSTEM TO THE SOUTH WILL BE ABLE TO WORK ITS WAY INTO THE AREA. FOR NOW...MAINTAINED SLIGHT CHANCE TO CHANCE POPS MID WEEK TO ACCOUNT FOR THESE VARIABLES...AND BROAD BRUSHED THE PERIOD. TEMPS LOOK TO REMAIN BELOW NORMAL FOR THE PERIOD. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... 12Z SATURDAY THRU 12Z SUNDAY... GENERALLY IFR/LIFR AREA WIDE THRU 00Z...THEN SLOWLY IMPROVING FROM WEST TO EAST TO MVFR THROUGH 07Z WITH A COLD FRONT THAT MOVES EAST ACROSS THE AREA. THRU 15Z...SNOW ACROSS THE NORTH...A WINTRY MIX OF SLEET AND FREEZING RAIN CENTRAL...FREEZING RAIN SOUTH. AFTER 15Z SNOW CONTINUES NORTH...WINTRY MIX TRANSITIONS TO RAIN ACROSS THE SOUTH BY 15Z...AND ACROSS THE CENTRAL BY 17Z. THESE CONDITIONS PERSIST TIL A COLD FRONT PASSES THRU TONIGHT. GUSTY SOUTHERLY WINDS TO 30 MPH ON MOUNTAIN RIDGE TOPS. AFTER 00Z...A WINTRY MIX RETURNING TO MOST AREAS BEFORE ENDING IN THE WEST BY 06Z...BUT IFR/LIFR STILL HOLDS FOR THE MOST PART. WINDS DIMINISHING. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY... FORECAST CONFIDENCE: LOW...ESPECIALLY WITH TIMING OF AND TRANSITION TO MIXED PRECIP. ALTERNATE SCENARIOS: LARGE VARIABILITY IN PRECIP TYPE AND TIMING...ESPECIALLY CENTRAL AND NORTH.I EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20 CRW CONSISTENCY M M M M M M H H H M M M HTS CONSISTENCY H H H H H M M M H H H M BKW CONSISTENCY M M M M M M H H H L M H EKN CONSISTENCY L H H M M M M M M M M M PKB CONSISTENCY H M M M M M H M M M M M CKB CONSISTENCY L H H H H M H M M M M M AFTER 12Z SUNDAY... IFR IN MIXED WINTRY PRECIPITATION AND RAIN SATURDAY NIGHT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR WVZ007>011-014>020-027>032-035>040. WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR WVZ005- 006-013-024>026-033-034. WINTER STORM WARNING UNTIL 4 AM EST SUNDAY FOR WVZ046-047. OH...WINTER STORM WARNING UNTIL 7 PM EST THIS EVENING FOR OHZ066- 067-075-076-083>086. WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR OHZ087. KY...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR KYZ101>103-105. VA...WINTER STORM WARNING UNTIL 5 PM EST THIS AFTERNOON FOR VAZ003- 004. && $$ SYNOPSIS...JMV/26 NEAR TERM...KMC SHORT TERM...26 LONG TERM...SL AVIATION...JMV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
647 AM EST SAT FEB 21 2015 .SYNOPSIS... A FAST MOVING LOW PRESSURE SYSTEM WILL MOVE NORTHEAST ACROSS CENTRAL OHIO INTO WESTERN PENNSYLVANIA TODAY. AN ARCTIC COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA MID DAY ON SUNDAY. HIGH PRESSURE WILL BUILD EAST EXTENDING A RIDGE EAST ACROSS THE LOCAL AREA SUNDAY NIGHT INTO MONDAY. ANOTHER COLD FRONT WILL MOVE SOUTH ACROSS THE AREA ON WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SNOW IS QUICKLY SPREADING NORTHEAST INTO THE AREA AT THIS TIME. MAIN AXIS OF THE HEAVIER SNOW APPEARS TO BE ON A LINE ACROSS THE SOUTHERN PORTIONS OF THE FORECAST AREA WHERE THE WINTER STORM WARNING IS IN EFFECT. ONLY MADE SOME MINOR ADJUSTMENTS TO HOURLY TEMPERATURES AT THIS TIME. REST OF THE FORECAST UNCHANGED. PREVIOUS DISCUSSION... LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE FORECAST AREA SPREADING SNOW INTO THE REGION. LATEST RADAR SHOWS SNOW EXPANDING AND MOVING NORTHEAST AT THIS TIME AND SHOULD COVER MUCH OF THE AREA BY SHORTLY AFTER SUNRISE. AT THIS TIME IT LOOKS THE THE PRECIPITATION SHOULD BE ALL SNOW. THERE IS THE POSSIBILITY THAT SOME FREEZING RAIN OR SLEET COULD MIX IN ACROSS THE DEEP SOUTH. BUT SINCE IT IS A LOW CONFIDENCE WILL LEAVE IT OUT FOR NOW. WARM AIR ADVECTION IN ADVANCE OF THE LOW PRESSURE SYSTEM WILL BOOST TEMPERATURES TO AROUND 30 IN THE SOUTH AND MOSTLY UPPER 20S IN THE NORTH TODAY. SNOW ACCUMULATIONS DROPPED BACK SLIGHTLY FROM PREVIOUS FORECAST AS BULK OF THE HEAVIER PRECIPITATION APPEARS IT WILL REMAIN A BIT FURTHER SOUTH THAN THOUGHT. LATEST MODEL RUNS HAVE THE STRONGEST UPWARD VERTICAL MOTION ACROSS THE OHIO VALLEY REGION. I HAVE A GUT FEELING WE MAY BE PULLING BACK ON THE SNOW AMOUNTS AS THE DAY PROGRESSES. EVEN THE LATEST HRRR MODEL IS SUGGESTING A TREND TOWARD FURTHER SOUTH. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... LOW PRESSURE PULLS OUT TO THE EAST ALLOWING COLDER AIR TO RETURN IN THE WAKE OF THE LOW. PRECIPITATION WILL QUICKLY PULL OUT TO THE EAST ALLOWING AN ARCTIC COLD FRONT TO MOVE SOUTHEAST DURING THE DAY SUNDAY. THIS FRONT WILL USHER IN ANOTHER ROUND OF ARCTIC AIR FOR SUNDAY NIGHT INTO MONDAY. SOME LAKE EFFECT SNOW SHOWERS WILL DEVELOP BEHIND THE FRONT AS WELL SUNDAY INTO SUNDAY NIGHT. EVENTUALLY THE HIGH PRESSURE RIDGE WILL BUILD IN ON MONDAY PUSHING THE THREAT OF THE PRECIPITATION OUT OF THE AREA. REST OF THE AREA WILL SEE SOME POSSIBILITY OF SNOW SHOWERS WITH THE ARCTIC FRONT BUT SHOULD SEE FAIR WEATHER GOING INTO MONDAY. ANOTHER LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS NORTHERN CANADA AND FORCE A COLD FRONT SOUTH ACROSS THE AREA. THIS FEATURE WILL BRING WITH IT ANOTHER ROUND OF SNOW SHOWERS TO THE REGION. UNFORTUNATELY...DUE TO THE REINFORCING SHOTS OF COLD AIR INTO THE AREA...THE COLD AIR WILL CONTINUE. APOLOGIES FOR GETTING THIS OUT SO LATE. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... UPPER LEVEL TROUGH WILL BE MOVING EAST OF THE REGION EARLY ON WEDNESDAY WITH SOME SNOW SHOWERS CONTINUING THROUGH THE DAY. AMOUNTS SHOULD BE ON LIGHTER SIDE WITH A LARGE AMOUNT OF ICE ON THE GREAT LAKES. HOWEVER A COUPLE INCHES OF FLUFFY SNOW WILL BE POSSIBLE. HIGH PRESSURE WILL BE RIDGING INTO THE REGION THURSDAY INTO THURSDAY NIGHT BUT PROBABLY WONT DECREASE THE SNOW SHOWERS MUCH UNTIL THE OVERNIGHT HOURS OF THURSDAY NIGHT. HIGH PRESSURE LOOKS TO BE OVERHEAD FRIDAY INTO INTO FRIDAY NIGHT WITH DRY AND COLD CONDITIONS. TEMPERATURES THROUGH THE LONG TERM WILL REMAIN WELL BELOW AVERAGE WITH HIGHS STRUGGLING TO GET INTO THE TEENS. CURRENT FORECAST MAY END UP BEING A FEW DEGREES WARM IF SKIES CAN BECOME CLEAR TO PARTLY CLOUDY SOONER THAN ANTICIPATED. LOWS WILL RANGE FROM AROUND ZERO TO A FEW DEGREES BELOW ZERO. THURSDAY NIGHT LOOKS TO BE THE COLDEST NIGHT WITH BEST CHANCES OF CLEAR SKIES AND LIGHT WINDS. THESE LOWS MAY BE ADJUSTED LOWER FOR THURSDAY NIGHT. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... IFR CONDITIONS ACROSS MUCH OF THE AREA AS LIGHT SNOW SPREADS ACROSS NORTHERN OHIO. THE EXCEPTIONS AS OF 1145Z ARE ACROSS NW OHIO AND NW PA. HOWEVER EXPECT MVFR/IFR SNOW TO OCCUR AT THESE LOCATIONS THROUGH THE DAY. HEAVIEST SWATH OF SNOW WILL BE ACROSS THE SOUTHERN HALF OF THE REGION FROM MARION TO YOUNGSTOWN. THIS IS THE AREA WHERE A VISIBILITY OF 1/2 MILE OR LESS WILL BE POSSIBLE FOR SEVERAL HOURS. ELSEWHERE THERE WILL BE BURST OF HEAVIER SNOW THROUGH THE AFTERNOON. CONDITIONS BEGIN TO IMPROVE THIS EVENING AS THE SNOW MOVES NE WITH THE WEAKENING AREA OF LOW PRESSURE. MVFR CONDITIONS SHOULD SPREAD ACROSS THE REGION FROM SOUTHWEST TO NORTHEAST AFTER 02Z. .OUTLOOK...NON VFR FAR NE OHIO AND NW PA POSSIBLY LINGERING INTO MONDAY. EXPECT NON VFR AGAIN TUESDAY AFTERNOON THEN CONTINUING THROUGH WEDNESDAY. && .MARINE... LOW PRESSURE WILL MOVE FROM THE LOWER OHIO RIVER VALLEY ACROSS CENTRAL OHIO INTO WESTERN NY THIS EVENING. HOWEVER IT WILL BE WEAKENING AS IT MOVES TO THE NORTHEAST. EXPECT TO SEE SOUTHERLY WINDS AHEAD OF THE LOW AT 5 TO 15 KNOTS SHIFTING TO THE NORTH BY THIS EVENING. A SURGE OF COLDER AIR WILL ARRIVE WITH THE ARCTIC COLD FRONT ON SUNDAY WITH NORTHWEST WINDS INCREASING TO 15 TO 25 KNOTS. WINDS WILL DECREASE BY SUNDAY NIGHT AS HIGH PRESSURE RIDGES INTO THE REGION. THIS HIGH PRESSURE WILL QUICKLY SHIFT TO THE EAST COAST ALLOWING LOW PRESSURE TO MOVE ACROSS SOUTHERN ONTARIO LATE TUESDAY INTO TUESDAY NIGHT. SOUTHWESTERLY WINDS AHEAD OF THE COLD FRONT MAY APPROACH 35 KNOTS. THIS MAY CONTINUE AS THE COLD FRONT CROSSES THE LAKE TUESDAY NIGHT BUT WILL BE FROM A NORTHWESTERLY DIRECTION. IT LOOKS LIKE A SMALL WINDOW OF OPPORTUNITY TO REACH GALES EITHER SIDE OF THE FRONT AT THIS POINT AND WILL PLACE A MENTION IN THE HWO. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR OHZ009>014-017>023-027-028-089. WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR OHZ029>033-036>038-047. PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR PAZ001>003. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY SHORT TERM...LOMBARDY LONG TERM...MULLEN AVIATION...MULLEN MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
433 AM EST SAT FEB 21 2015 .SYNOPSIS... A FAST MOVING LOW PRESSURE SYSTEM WILL MOVE NORTHEAST ACROSS CENTRAL OHIO INTO WESTERN PENNSYLVANIA TODAY. AN ARCTIC COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA MID DAY ON SUNDAY. HIGH PRESSURE WILL BUILD EAST EXTENDING A RIDGE EAST ACROSS THE LOCAL AREA SUNDAY NIGHT INTO MONDAY. ANOTHER COLD FRONT WILL MOVE SOUTH ACROSS THE AREA ON WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LOW PRESSURE WILL MOVE NORTHEAST ACROSS THE FORECAST AREA SPREADING SNOW INTO THE REGION. LATEST RADAR SHOWS SNOW EXPANDING AND MOVING NORTHEAST AT THIS TIME AND SHOULD COVER MUCH OF THE AREA BY SHORTLY AFTER SUNRISE. AT THIS TIME IT LOOKS THE THE PRECIPITATION SHOULD BE ALL SNOW. THERE IS THE POSSIBILITY THAT SOME FREEZING RAIN OR SLEET COULD MIX IN ACROSS THE DEEP SOUTH. BUT SINCE IT IS A LOW CONFIDENCE WILL LEAVE IT OUT FOR NOW. WARM AIR ADVECTION IN ADVANCE OF THE LOW PRESSURE SYSTEM WILL BOOST TEMPERATURES TO AROUND 30 IN THE SOUTH AND MOSTLY UPPER 20S IN THE NORTH TODAY. SNOW ACCUMULATIONS DROPPED BACK SLIGHTLY FROM PREVIOUS FORECAST AS BULK OF THE HEAVIER PRECIPITATION APPEARS IT WILL REMAIN A BIT FURTHER SOUTH THAN THOUGHT. LATEST MODEL RUNS HAVE THE STRONGEST UPWARD VERTICAL MOTION ACROSS THE OHIO VALLEY REGION. I HAVE A GUT FEELING WE MAY BE PULLING BACK ON THE SNOW AMOUNTS AS THE DAY PROGRESSES. EVEN THE LATEST HRRR MODEL IS SUGGESTING A TREND TOWARD FURTHER SOUTH. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... LOW PRESSURE PULLS OUT TO THE EAST ALLOWING COLDER AIR TO RETURN IN THE WAKE OF THE LOW. PRECIPITATION WILL QUICKLY PULL OUT TO THE EAST ALLOWING AN ARCTIC COLD FRONT TO MOVE SOUTHEAST DURING THE DAY SUNDAY. THIS FRONT WILL USHER IN ANOTHER ROUND OF ARCTIC AIR FOR SUNDAY NIGHT INTO MONDAY. SOME LAKE EFFECT SNOW SHOWERS WILL DEVELOP BEHIND THE FRONT AS WELL SUNDAY INTO SUNDAY NIGHT. EVENTUALLY THE HIGH PRESSURE RIDGE WILL BUILD IN ON MONDAY PUSHING THE THREAT OF THE PRECIPITATION OUT OF THE AREA. REST OF THE AREA WILL SEE SOME POSSIBILITY OF SNOW SHOWERS WITH THE ARCTIC FRONT BUT SHOULD SEE FAIR WEATHER GOING INTO MONDAY. ANOTHER LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS NORTHERN CANADA AND FORCE A COLD FRONT SOUTH ACROSS THE AREA. THIS FEATURE WILL BRING WITH IT ANOTHER ROUND OF SNOW SHOWERS TO THE REGION. UNFORTUNATELY...DUE TO THE REINFORCING SHOTS OF COLD AIR INTO THE AREA...THE COLD AIR WILL CONTINUE. APOLOGIES FOR GETTING THIS OUT SO LATE. && .LONG TERM /WEDNESDAY THROUGH FRIDAY/... UPPER LEVEL TROUGH WILL BE MOVING EAST OF THE REGION EARLY ON WEDNESDAY WITH SOME SNOW SHOWERS CONTINUING THROUGH THE DAY. AMOUNTS SHOULD BE ON LIGHTER SIDE WITH A LARGE AMOUNT OF ICE ON THE GREAT LAKES. HOWEVER A COUPLE INCHES OF FLUFFY SNOW WILL BE POSSIBLE. HIGH PRESSURE WILL BE RIDGING INTO THE REGION THURSDAY INTO THURSDAY NIGHT BUT PROBABLY WONT DECREASE THE SNOW SHOWERS MUCH UNTIL THE OVERNIGHT HOURS OF THURSDAY NIGHT. HIGH PRESSURE LOOKS TO BE OVERHEAD FRIDAY INTO INTO FRIDAY NIGHT WITH DRY AND COLD CONDITIONS. TEMPERATURES THROUGH THE LONG TERM WILL REMAIN WELL BELOW AVERAGE WITH HIGHS STRUGGLING TO GET INTO THE TEENS. CURRENT FORECAST MAY END UP BEING A FEW DEGREES WARM IF SKIES CAN BECOME CLEAR TO PARTLY CLOUDY SOONER THAN ANTICIPATED. LOWS WILL RANGE FROM AROUND ZERO TO A FEW DEGREES BELOW ZERO. THURSDAY NIGHT LOOKS TO BE THE COLDEST NIGHT WITH BEST CHANCES OF CLEAR SKIES AND LIGHT WINDS. THESE LOWS MAY BE ADJUSTED LOWER FOR THURSDAY NIGHT. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... HAVE SLOWED DOWN THE START OF THE SNOW SLIGHTLY BASED ON THE NEW GUIDANCE. STILL EXPECT CONDITIONS TO DETERIORATE TO IFR SATURDAY MORNING. PERIODS OF IFR VSBYS ARE EXPECTED MOST OF THE DAY...ESPECIALLY IN THE SOUTH WHERE THE SNOW WILL BE THE HEAVIEST. CONDITIONS SHOULD START TO IMPROVE FROM WEST TO EAST LATE IN THE DAY. SOME INDICATION FROM THE NEW GUIDANCE THAT THERE COULD BE A PERIOD OF FREEZING DRIZZLE AT THE TAIL END OF THE SNOW. SOME UNCERTAINTY WITH THIS SCENARIO SO WILL OMIT FROM THE FORECAST FOR NOW. SOUTHERLY WINDS HAVE GOTTEN GUSTY SOME AREAS BUT THESE SHOULD DIE DOWN SOME OVERNIGHT. THE FLOW WILL BECOME WESTERLY SATURDAY EVENING. .OUTLOOK...NON VFR CONDITIONS WILL CONTINUE SATURDAY NIGHT. CONDITIONS WILL IMPROVE TO VFR FROM THE WEST SUNDAY WITH THE POSSIBLE EXCEPTION OF FAR NORTHEAST OHIO AND NWRN PA WHEN NON-VFR REMAINS POSSIBLE THROUGH MONDAY. EXPECT NON VFR AGAIN TUESDAY AFTERNOON AND TUESDAY NIGHT INTO WEDNESDAY. && .MARINE... LOW PRESSURE WILL MOVE FROM THE LOWER OHIO RIVER VALLEY ACROSS CENTRAL OHIO INTO WESTERN NY THIS EVENING. HOWEVER IT WILL BE WEAKENING AS IT MOVES TO THE NORTHEAST. EXPECT TO SEE SOUTHERLY WINDS AHEAD OF THE LOW AT 5 TO 15 KNOTS SHIFTING TO THE NORTH BY THIS EVENING. A SURGE OF COLDER AIR WILL ARRIVE WITH THE ARCTIC COLD FRONT ON SUNDAY WITH NORTHWEST WINDS INCREASING TO 15 TO 25 KNOTS. WINDS WILL DECREASE BY SUNDAY NIGHT AS HIGH PRESSURE RIDGES INTO THE REGION. THIS HIGH PRESSURE WILL QUICKLY SHIFT TO THE EAST COAST ALLOWING LOW PRESSURE TO MOVE ACROSS SOUTHERN ONTARIO LATE TUESDAY INTO TUESDAY NIGHT. SOUTHWESTERLY WINDS AHEAD OF THE COLD FRONT MAY APPROACH 35 KNOTS. THIS MAY CONTINUE AS THE COLD FRONT CROSSES THE LAKE TUESDAY NIGHT BUT WILL BE FROM A NORTHWESTERLY DIRECTION. IT LOOKS LIKE A SMALL WINDOW OF OPPORTUNITY TO REACH GALES EITHER SIDE OF THE FRONT AT THIS POINT AND WILL PLACE A MENTION IN THE HWO. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR OHZ009>014-017>023-027-028-089. WINTER STORM WARNING UNTIL 10 PM EST THIS EVENING FOR OHZ029>033-036>038-047. PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR PAZ001>003. MARINE...NONE. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY SHORT TERM...LOMBARDY LONG TERM...MULLEN AVIATION...KUBINA MARINE...MULLEN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1033 AM EST SAT FEB 21 2015 .SYNOPSIS... A WIDESPREAD SNOW EVENT WILL IMPACT CENTRAL PENNSYLVANIA TODAY INTO EARLY TONIGHT. AN ARCTIC AIRMASS WILL THREATEN EXTREME COLD AND DANGEROUS WIND CHILLS THROUGH EARLY NEXT WEEK. TEMPERATURES WILL REMAIN WELL BELOW NORMAL AS COLD AIR IS REINFORCED LATER IN THE WEEK. && .NEAR TERM /THROUGH TONIGHT/... 1000 AM UPDATE...ADDED YORK/LANCASTER COUNTIES TO THE WSW BASED ON A BLEND OF PREVIOUS FCST WITH CONSENSUS OF HI RES MODEL DATA. THIS FAVORS ALL SNOW PTYPE INTO THE EVENING WITH 1-2 INCH PER HOUR RATES POSSIBLE OVER THE SRN TIER ZONES. THE LATEST HRRR AND 00Z SSEO SEEM TO FAVOR MAX SNOW AMTS OVER S-CENTRAL PA FROM THE TURNPIKE TO THE MASON DIXON LINE. THESE DATA ALSO SHOW A TRANSITION TO WINTRY MIX /ZR AND IP/ BTWN 00-03Z OVER THE FAR SE BEFORE PCPN ENDS AS LIGHT RAIN/DZ OR FZDZ INTO EARLY SUNDAY MORNING. RADAR TRENDS MAY BE SHOWING THE DEVELOPMENT OF HEAVY SNOW BAND CURRENTLY DEVELOPING OVER NRN MD (+SN AT HGR AND MRB) AND STREAKING TOWARD THE RT30 CORRIDOR. THE HRRR HAS ALSO HINTED AT THIS FOR THE LAST FEW RUNS. TO THE NORTH...CUT BACK A LITTLE ON PREVIOUS SNFL AMTS IN THE ORIGINAL WARNING/ADVY AREA SUPPORTED BY A BLEND OF 09Z SREF/06Z GEFS ENSEMBLE MEANS AND 00Z HIGH RES MEAN/SSEO. ALSO REMOVED ICE ACCUM FOR ALL BUT THE FAR SE WITH ANY POST-EVENT FZDZ AMTS AROUND A TRACE. OVERALL HIGHEST CONFIDENCE IN WARNING SNOWS IS NOW OVER THE SRN TIER ZONES AND WILL PROBABLY NEED A FEW PERIODS/BURSTS OF MOD-HVY SNOW TO ACHIEVE IT. TERRAIN ENHANCEMENT MAY ALSO HELP. CONFIDENCE IS MARGINAL OVER THE NRN PORTION OF THE WARNING AREA IN AND WILL SEE HOW THINGS EVOLVE INTO THE AFTN. THE OVERALL SYNOPTIC FORCING FOR THIS WINTER WX EVENT IS DRIVEN PRIMARILY BY WARM ADVECTION PROCESSES WITH AN ANOMALOUS MOISTURE FLUX SURGING NEWD INTO THE MID ATLC STATES ON NOSE OF 60+KT 850MB JET CENTERED OVER THE TN VLY/CENTRAL APPALACHIANS. THE WARM ADVECTION EVENT SHOULD END AS A PERIOD OF FZDZ PER MODEL SOUNDINGS SHOWING NO ICE ALOFT AS THE PCPN TAPERS OFF. LOW TEMPS SHOULD OCCUR EARLY TONIGHT WITH A NON-DIURNAL TREND FCST OVERNIGHT INTO EARLY SUNDAY MORNING. && .SHORT TERM /SUNDAY/... THE COLD FRONT SHOULD BE MOVING THROUGH MY SERN ZONES BY EARLY SUNDAY MORNING. COLDER AIR WILL BEGIN FILTERING INTO THE STATE DURING THE DAY...BUT NOT BEFORE WE SEE SOME OF THE MILDEST DAYTIME HIGHS WE HAVE SEEN IN A WHILE. PRECIPITATION WILL TAPER OFF TO THE USUAL POST COLD FRONTAL SNOW SHOWERS WHICH WILL MAINLY FAVOR WESTERN AND NORTHERN HIGH TERRAIN. ACCUMS IF ANY WILL BE LIGHT AND INCONSEQUENTIAL. FOR WHAT IT`S WORTH...THE OPERATIONAL GFS LOOKS WAY TOO WET WITH THE LARGE AREA OF LIGHT QPF IT KEEPS HANGING AROUND OVER WESTERN AREAS ALL DAY. I PREFER THE DRIER/LOWER GEFS POPS. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... THE LAST WEEK OF THE MONTH LOOKS TO BE A COLD ONE AS AT LEAST TWO SEPARATE ARCTIC AIRMASSES ARE POISED TO INFLUENCE OUR WEATHER. THE FIRST CHUNK OF COLD AIR WILL BE MOVING IN BEHIND THE SYSTEM SLATED TO AFFECT US TODAY...WITH TEMPERATURES BY MONDAY MORNING RETURNING TO THE ALL TOO FAMILIAR FRIGID LEVELS WE HAVE EXPERIENCED RECENTLY. HIGH PRESSURE WILL MOVE EAST OF THE AREA BY TUESDAY PAVING THE WAY FOR ANOTHER CLIPPER LOW AND ARCTIC AIRMASS. THE FRONTAL TIMING IS DIFFERENT BETWEEN THE OPERATIONAL ECMWF AND GFS...BUT BOTH DRAG THE FRONT THROUGH SOME TIME WEDNESDAY BRINGING STILL MORE DEEP WINTER CHILL TO THE AREA TO LAST THROUGH LATE WEEK. THE GOOD NEWS...THE NW FLOW ALOFT AND DEEP ARCTIC CHILL WILL SUPPRESS ANY SIGNIFICANT STORMINESS SOUTH OF THE REGION. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... HIGH PRES MOVING EAST OF PA CONTINUES TO PROVIDE VFR FLYING CONDS FOR A FEW MORE HOURS AT MOST TAF SITES. BUT CLOUDS ARE THICKENING AHEAD OF A STORM SYSTEM EXPECTED TO LIFT NORTHWARD INTO THE OHIO VALLEY BY THIS EVENING. SNOW SPREADING EASTWARD AHEAD OF THIS SYSTEM WILL LEAD TO RAPIDLY DETERIORATING VSBYS AND CIGS THIS MORNING IN THE WEST INTO EARLY AFTERNOON ACROSS THE EAST. LATEST RADAR IMAGERY AND SFC OBS SHOW SNOW MOVING INTO WESTERN PA. BASIC EXTRAPOLATION AND MESO MODEL SIMULATED RADAR SUGGEST STEADY SNOW WILL REACH KJST AND KBFD BETWEEN 13Z-15Z...KUNV AND KIPT BETWEEN 14Z-16Z AND KMDT/KLNS BTWEEN 15Z-17Z. WIDESPREAD IFR/LIFR CONDS IN SNOW APPEAR VERY LIKELY ACROSS ALL OF CENTRAL PA THRU AT LEAST EARLY SAT EVENING. THE HEAVIEST SNOW AND LOWEST VSBYS WILL BE ACROSS THE SOUTHERN PART OF THE STATE. SNOW ACROSS THE NORTH AND MIXED PRECIP OVER THE SOUTH WILL LIKELY TAPER OFF SAT NIGHT...AS THE LOW PRES SYSTEM PASSES NORTH OF PA. HOWEVER...LOW CIGS MAY STILL BE PRESENT THRU DAWN IN LOW CIGS AND REDUCED VSBYS IN FOG AND DRIZZLE. OUTLOOK... SUN...AM SHRASN/LOW CIGS POSSIBLE...ESP KJST/KMDT/KLNS. MON...NO SIG WX EXPECTED. TUE...SNOW SHOWERS/REDUCED VSBYS POSS W MTNS TUE NIGHT. WED...AM SNOW SHOWERS/REDUCED VSBYS POSS W MTNS. && .CTP WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 7 AM EST SUNDAY FOR PAZ017>019- 024>028-033>036-042-045-046-049>053-056>059-063>066. WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR PAZ004>006- 010>012-037-041. && $$ SYNOPSIS...LA CORTE/STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...LA CORTE LONG TERM...LA CORTE AVIATION...GARTNER
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1013 AM EST SAT FEB 21 2015 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE WEST TODAY AND WILL CROSS THE REGION TONIGHT. AN ARCTIC COLD FRONT WILL MOVE ACROSS THE REGION LATE SUNDAY WITH VERY COLD HIGH PRESSURE RETURNING EARLY NEXT WEEK. CONDITIONS MAY REMAIN UNSETTLED THROUGH MID TO LATE WEEK AS A MOIST SURFACE BOUNDARY LINGERS TO THE SOUTH. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1000 AM EST...RADAR RETURNS FILLED BACK IN ACROSS THE NRN HALF OF GA THIS MORNING...BUT SFC OBS HAVE MOSTLY 6 TO 9 KFT CLOUD BASES WITH ONLY LIGHT PRECIPITATION REACHING THE GROUND IN A FEW SPOTS. IN ADDITION...THE LATEST HRRR HAS THE BAND OF PRECIP DECAYING AS IT MOVES EAST THROUGH LATE MORNING/EARLY AFTN. THUS PLAN NO EXPANSION TO THE CURRENT WINTER WEATHER ADVISORY. HAZARD PRODUCTS APPEAR ADEQUATELY PLACED THROUGHOUT AS MANY NC MTN AND FOOTHILL LOCATIONS HAVE HAD AN ACCUMULATING MIXED BAG...BUT SOME DRYING IN PROFILES IS STILL ANTICIPATED EAST OF THE MTNS. JUST ABOUT ANYONE COULD SEE A BRIEF PERIOD OF SLEET WITH ANY SHOWERS THAT PASS OVERHEAD...BUT ANY ACCUMULATING SNOW...SLEET...ICE SHOULD BE CONFINED TO ADVISORY OR WARNING LOCATIONS THROUGH LATE DAY. FOR TONIGHT...THE MODELS ARE IN GOOD AGREEMENT WITH FINALLY MOVING THE FRONTAL ZONE EASTWARD...SO PRECIP PROBABILITIES GRADUALLY RAMP UP FROM THE WEST WITH LIKELY/CATEGORICAL LOOKING LIKE A GOOD BET. TEMPS WILL ACTUALLY WARM A BIT OVERNIGHT...WITH ONLY RAIN EXPECTED ACROSS THE WHOLE FCST AREA DURING THE PERIOD OF BEST QPF. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 300 AM EST SATURDAY...THE SHORT TERM FCST PERIOD INITIALIZES SUNDAY MORNING AMIDST ONGOING SURFACE FROPA. BROAD LONGWAVE UPPER TROF CENTERED OVER THE CENTRAL/EASTERN CONUS WILL DOMINATE WITH QUASIZONAL FLOW AROUND THE TROF BASE OVER THE SOUTHERN APPALACHIANS. ABOVE MENTIONED SURFACE COLD FRONT WILL SLIDE THROUGH THE REGION DURING THE MORNING HOURS WITH A BAND OF PREFRONTAL PRECIP OUT AHEAD. THERMAL PROFILES AT THE TIME WILL BE TOO WARM FOR ANY WINTRY PTYPE CONCERNS THEREFORE FCST FEATURES SOLID LIKELY LEVEL POPS AT INITIALIZATION FOR RAIN...BEFORE TAPERING DOWN TO SLIGHT CHANCE LEVELS THROUGH THE AFTERNOON INTO THE EVENING AS THE FROPA/CAA OCCUR. SLIGHTLY HIGHER POPS WILL RESIDE OVER THE NC MOUNTAINS SUNDAY NIGHT AS BRIEF SHOT OF NORTHWEST FLOW MOISTURE AMONGST FALLING SNOW LEVELS COULD LEAD TO MINOR BOUTS OF SNOWFALL. THE FRONTAL BOUNDARY SLOWS INTO MONDAY LEADING TO LINGERING LOW END POPS SOUTH OF INTERSTATE 85 WHERE PROFILES SUPPORT ALL RAIN PROCESSES. MEANWHILE...SURFACE HIGH PRESSURE SLIDING THROUGH THE OH VALLEY WILL SLIDE EAST ATOP THE CENTRAL APPS THROUGH THE DAY ON MONDAY YIELDING BRIEF CAD WEDGE REGIME DEVELOPMENT ON THE LEE SIDE OF THE APPS INTO THE NIGHTTIME HOURS. ADDITIONALLY...GULF COASTAL WAVE DEVELOPMENT WILL SPREAD MOISTURE NORTHWARD YIELDING UPGLIDE INDUCED PRECIP ATOP THE ABOVE MENTIONED INTRUDING WEDGE BOUNDARY. THEREFORE THE SHORT TERM CONCLUDES WITH DRY FCST REGIONWIDE LATE DAY MONDAY BEFORE SLIGHT CHANCE POPS ARE REINTRODUCED INTO TUESDAY MORNING ACROSS THE MTNS. MODEL SOUNDINGS AT THAT TIME INDICATE ALL SNOW SUPPORTIVE PROFILES THUS THE FCST HIGHLIGHTS LIGHT SNOW SHOWERS. TEMPERATURES THROUGH THE SHORT TERM WILL RETURN TO NEAR NORMAL LEVELS ON SUNDAY DUE WAA REGIME AHEAD OF THE FRONT AND NON DIURNAL TRENDS DURING THE MID/LATE MORNING. BEHIND THE FRONT ON MONDAY EXPECTING TEMPERATURES TO FALL BACK TO NEARLY 10 DEGREES BELOW NORMAL. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 330 AM EST SATURDAY...THE MEDIUM RANGE FCST PERIOD INITIALIZES TUESDAY MORNING WITH SLIGHT CHANCE POPS PRESENT ALONG THE MTNS OF WESTERN NC AND NORTHEAST GA DUE TO WEAK UPGLIDE ATOP INTRUDING WEDGE BOUNDARY. SAID UPGLIDE WILL BE FORCED BY A DEVELOPING GULF COAST WAVE WHICH IS ACTUALLY FAIRLY CONSISTENT IN BOTH THE ECMWF/GFS. DIFFERENCES DO ARISE WITH THE EVENTUAL NORTHWARD EXTEND OF THE PRECIP ASSOCIATED WITH THIS WAVE...WITH THE ECMWF BEING THE MOST AGGRESSIVE. MEANWHILE...THE GFS FAVORS PASSAGE OF A SURFACE TROF/COLD FRONT ON TUESDAY NIGHT WITH MODEST NW H85 FLOW BANKING UP AGAINST THE WESTERN SLOPES OF THE NC MTNS...THUS FAVORING NWFS REGIME. THEREFORE THE FCST FEATURES A BLEND OF THE TWO WITH POPS INCREASING TUESDAY NIGHT ACROSS THE FCST AREA FROM THE SOUTH WITH AN ADDITIONAL INCREASE ALONG THE SPINE OF THE APPS FOR ABOVE MENTIONED NWFS POSSIBILITIES. THUS BY WEDNESDAY NIGHT SOLID SLIGHT CHANCE POPS ARE FAVORED REGIONWIDE WITH THE EXCEPTION OF THE NW PIEDMONT DUE TO FURTHEST PROXIMITY TO THE SOUTHERN STREAM LOW. THERMAL PROFILES AT THE TIME WILL BE COLD ENOUGH TO SUPPORT SNOWFALL TUESDAY NIGHT BEFORE LOW LEVEL WARMING PREVAILS ON WEDNESDAY LEADING TO ALL RAIN WITH THE EXCEPTION OF THE HIGHER ELEVATIONS WHERE SNOW SHOWERS REMAIN IN THE FCST. MODEL QPF REMAINS LIGHT DURING THIS TIME SO ACCUMULATIONS REMAIN MINIMAL AT BEST. MOVING ALONG INTO THURSDAY...MODELS FAVOR A QUICK CHANGEOVER BACK TO SNOW INTO THE MID MORNING HOURS BEFORE ALL POPS ARE REMOVED ACROSS THE REGION. FROM THAT POINT FORWARD MODELS CONTINUE TO SUGGEST SURFACE CYCLOGENESIS BY LATE WEEK AND INTO THE WEEKEND WHILE A SUBSTANTIAL 1040MB SURFACE HIGH SETS UP ATOP NEW ENGLAND. MODELS DISAGREE AT THIS RANGE REGARDING TIMING OF ISENTROPIC UPGLIDE PRECIP ONSET DUE TO POTENTIAL CAD WEDGE INTRUSION AS THE GFS IS ABOUT 6-12 HOURS AHEAD OF THE ECMWF WITH PRECIP SPREADING NORTHWARD INTO THE REGION FRIDAY NIGHT INTO SATURDAY MORNING IN THE FORM RAIN AHEAD OF A QUICK TRANSITION TO SNOW. THIS WILL BE HIGHLY DEPENDENT ON THE TIMING OF PRECIP ONSET...AND AT THIS RANGE...LITTLE CONFIDENCE RESIDES IN THE CURRENT MODEL PROGS DUE TO ABOVE MENTIONED TIMING DISCONTINUITIES. TEMPERATURES THROUGH THE MEDIUM RANGE WILL REMAIN BELOW NORMAL AS PRIMARY UPPER BROAD SCALE TROF PERSISTS OVER THE EAST/CENTRAL CONUS. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... AT KCLT...THE MORNING BAND OF LIGHT PRECIPITATION HAS LARGELY MISSED KCLT. HOWEVER...MOIST UPGLIDE AT LOW LEVELS WILL STILL YIELD MVFR CIGS FOR A COUPLE OF HOURS INTO THE EARLY AFTERNOON. OTHERWISE...WILL RIDE ON A VCSH MENTION FOR ANY SPOTTY LIGHT SLEET...WITH A TRANSITION BACK TO VFR AFTER 18Z. LOWER CIGS WILL FILL BACK IN TONIGHT AS THE DEEPER MOISTURE BAND WITH THE COLD FRONT ARRIVES...BUT TEMPS SHOULD BE SOLIDLY ABOVE FREEZING AT THAT POINT. EXPECT MAINLY SE TO S WINDS LESS THAN 10 KT. ELSEWHERE OUTSIDE THE MTNS...VFR EXPECTED THROUGH THE DAYTIME PERIOD. KHKY WILL SEE THE BEST CHANCE OF LIGHT SNOW OR SLEET...BUT THE CHANCES WILL WANE THROUGH THE DAY AS DRIER AIR ARRIVES FROM THE S. ANTICIPATE A RETURN TO MVFR AND THE IFR OVERNIGHT AS THE BETTER MOISTURE ARRIVES WITH THE COLD FRONT...BUT WITH ALL LIQUID PTYPES BY THEN. WINDS SHOULD STAY SSE TO SW. AT KAVL...LIGHT SN OR PL WILL FALL AT TIMES IN THE WEAK UPGLIDE OVER THE MTNS TODAY. ANY PRECIP COULD BRIEFLY TAKE CIGS DOWN TO MVFR...BUT MAINLY VFR IS EXPECTED. THERE IS ALSO A SMALL CHANCE OF FZRA LATE. A STRENGTHENING LOW LEVEL JET WILL BRING LOW LEVEL WIND SHEAR OVERHEAD STARTING AROUND MIDDAY. TEMPS SHOULD WARM UP ENUF SUCH THAT ONLY RAIN IS EXPECTED FROM LATE AFTERNOON ONWARD...ESPECIALLY INTO TONIGHT WHEN THE BETTER QPF WITH THE COLD FRONT AND LOWER RESTRICTIONS RETURN. OUTLOOK...UNSETTLED WEATHER WILL CONTINUE SUNDAY AS A COLD FRONT MOVES SE OVER THE CAROLINAS. RESTRICTIONS ARE LIKELY. TEMPERATURES SHOULD BE WARM ENUF THAT ONLY RAIN IS EXPECTED. ADDITIONAL WAVES OF LOW PRESSURE MAY MOVE ALONG A FRONT STALLED OFF THE SE COAST THROUGH MOST OF NEXT WEEK...BUT THE CONFIDENCE IN ANY OF THESE WAVES PASSING CLOSE ENUF TO RAISE ANY RESTRICTIONS IS LOW. CONFIDENCE TABLE... 13-19Z 19-01Z 01-07Z 07-12Z KCLT HIGH 95% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL MED 74% HIGH 100% HIGH 100% HIGH 100% KHKY MED 77% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .GSP WATCHES/WARNINGS/ADVISORIES... GA...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR GAZ010- 017-018. NC...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR NCZ035>037-048-051>053-056>059-062>065-068-069-501>510. WINTER STORM WARNING UNTIL 8 PM EST THIS EVENING FOR NCZ033- 049-050. SC...WINTER WEATHER ADVISORY UNTIL 8 PM EST THIS EVENING FOR SCZ001>003. && $$ SYNOPSIS...PM NEAR TERM...HG/PM SHORT TERM...CDG LONG TERM...CDG AVIATION...HG/PM
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
848 AM CST SAT FEB 21 2015 .MESOSCALE UPDATE... ICE ACCUMULATIONS AROUND 1 INCH ALONG PLATEAU WILL LET ICE STORM WARNING EXPIRE AT 9 AM CST BUT WILL ISSUED SPS TO MENTION TEMPS NOW ABOVE FREEZING MOST AREAS...BUT STILL COULD BE ISOLATED LOCATIONS WHERE TEMPS ARE RIGHT AT 32 DEGREES BUT WILL RISE ABOVE FREEZING WITHIN THE NEXT HOUR OR TWO. WE`VE HAD REPORTS OF 1/2 TO 1 INCH OF ICE ALONG THE PLATEAU OVERNIGHT WITH SOME POWER OUTAGES AND SNAPPING BRANCHES BEING REPORTED. HAVE SOME CONCERN FOR GUSTY WINDS SINCE LATEST RUC SHOWING TIGHT PRESSURE GRADIENT BETWEEN TENNESSEE RIVER AND EASTERN TENNESSEE. COULD ALSO SEE STRONGER ISALLOBARIC WINDS AT TIMES THIS MORNING. SURFACE LOW CENTERED TO OUR SOUTHWEST NEAR TEXARKANA WITH WARM FRONT STRETCHED FROM LOW UP INTO KENTUCKY...NORTH OF MID STATE. LOW LEVEL JET THE STRONGEST I`VE EVEN SEEN AT 850 MBARS...86 KNOTS OFF 12Z OHX RAOB. THAT MEANS PLENTY OF LOW LEVEL WARM ADVECTION PUMPING UP INTO MIDDLE TENNESSEE NEXT SEVERAL HOURS. WITH TOTAL TOTALS AT 51 WE COULD SEE ISOLATED THUNDERSTORMS EMBEDDED A MUCH LARGER RAIN AREA DURING THE DAY. 0-3 STORM RELATIVE HELICITY 1862 M2/S2. SWEAT INDEX AT 453. LOOKS LIKE 2 TO 4 INCH RAIN TOTALS WITH UP TO 5 INCHES AND POSSIBLY A A LITTLE MORE OVER THE NORTHWEST THROUGH NOON SUNDAY. PONDING OF WATER ON ROADWAYS WILL BE AN ISSUE WITH ICE DAMMING OCCURRING. && .OHX WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH THROUGH SUNDAY MORNING FOR TNZ005>011-023>034- 056>066-075-077>080. ICE STORM WARNING UNTIL 9 AM CST THIS MORNING FOR TNZ010-011- 031>034-065-066-077>080. && $$ BOYD 01
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
955 PM CST Sun Feb 22 2015 .UPDATE... Based on radar data, it appears we`re in a bit of a lull across the area now. However, calls across the CWA and automated surface observations indicate that widespread, light freezing drizzle is occurring in many areas. Temperatures continue to run a few degrees below even the coldest guidance, with current readings in the 20s everywhere excluding the I-10 corridor (lower 30s). Temperatures will continue to slowly drop tonight, setting the stage for the next shortwave trough. The primary wave looks to be moving across the northern Baja Peninsula at this time, with notable forced ascent downstream over AZ, NM, and northern Mexico. There is a band of frontogenetic forcing sloping up and over the cold dome from north to south that is progged to persist into Monday morning before weakening. This area of mesoscale lift should be enhanced by the approaching shortwave energy. The going forecast looks to be in relatively good shape. The wx grids were modified for this evening, with widespread drizzle and only a chance for sleet mentioned areawide. However, after midnight, we expect additional precipitation to develop. Point soundings suggest the favored precipitation types to be sleet and freezing rain. However, both the NAM and RAP soundings show the cold near surface layer (below the inversion) to be near -10C. While this generally favors supercooled liquid hydrometeors, this is a borderline temperature for the activation of ice nuclei. This would account for the very light snow we`ve had reported over the past few hours. Expect snow accumulations to be a dusting or less. With elevated instability in place, this precipitation should be more convective in nature, with the potential for thundersleet overnight. In areas that do experience thunder, the enhanced convective updrafts may lead to localized higher amounts of sleet and/or snow. Precipitation is expected to diminish by Monday afternoon, although freezing drizzle will remain possible even into Monday evening. Expect surface temperatures on Monday to remain well below freezing, with highs in the mid/upper 20s. There may be just enough radiation coming through the thick overcast to improve road surfaces on Monday, but most of the ice should persist into Tuesday morning. Johnson && .PREV DISCUSSION... /ISSUED 514 PM CST Sun Feb 22 2015/ AVIATION... /00Z TAFS/ Generally LIFR/IFR conditions are being experienced at all sites this evening and are forecast to continue through the next 24 hours. Light freezing drizzle continues at KABI and is forecast to develop at KSJT around 00z as temperatures drop to or below freezing. Light drizzle will continue at the other sites then transition to light freezing drizzle late this evening as temperatures drop below freezing. Areas of light freezing rain/sleet may develop after midnight, mainly at KABI and KSJT. Northeast winds of 12 to 20 knots, with higher gusts, will decrease to 8 to 12 knots by late morning Monday. PREV DISCUSSION... /ISSUED 409 PM CST Sun Feb 22 2015/ SHORT TERM... (Tonight through Tuesday morning) The much talked about winter storm is beginning to affect the area. Another cold front was crossing the area at 3 PM and was located along an Ozona to just south of Brownwood line, with cold air rapidly invading the area behind this front. Trends in the observations are showing temperatures dropping 5 to 10 degrees per hour behind it. In fact, many areas along/north of Interstate 20 have already dropped below freezing with freezing rain, sleet, and ice accumulations already occurring per social media, phone calls, and observations. Given these developments over the last few hours, and after coordinating with surrounding offices, the Winter Storm Warning start time has been increased to 4 PM this afternoon. Things continue to look like they`ll get messy through tomorrow. The numerical models remain consistent dropping temperatures into the lower to mid 20s across the warned area, and near freezing farther south, with not much recovery tomorrow afternoon. They have also trended stronger/farther south with their convective signature. The Storm Prediction Center has most of West Central Texas in a risk for thunder tonight/tomorrow and model soundings show 100-250 J/kg of MUCAPE across the entire forecast area during this period. As a result, thunder was included in all zones for tonight through mid afternoon tomorrow. LONG TERM... (Tuesday through Sunday) All hands on board for the first winter storm, so this part of the discussion will be brief. Warming trend starts on Tuesday afternoon, although it will be modest. A few breaks in the clouds will allow a little sun, enough to allow temperatures to climb into the 40s. Another upper level low will drop into the southwest US, with return flow ahead of it allowing readings to climb into the 60s on Wednesday. Next arctic front moves across the area for Thursday and Friday, just ahead of the upper level trough moving across. GFS and the ECMWF have some differences in the strength of this system, with the GFS shearing it out a little faster. For now, kept the compromise intact and have slight chance to chance PoPs across the area. Models did warm just a tad, so was able to shift the mention of snow a little farther north. && .PRELIMINARY POINT TEMPS/POPS... Abilene 21 25 20 40 29 / 90 80 10 10 5 San Angelo 25 29 25 46 31 / 90 70 10 10 5 Junction 29 32 28 48 34 / 80 70 10 10 10 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING until 6 PM CST Monday FOR THE FOLLOWING ZONES: Brown...Callahan...Coke...Coleman...Concho...Fisher... Haskell...Irion...Jones...Nolan...Runnels...Shackelford... Sterling...Taylor...Throckmorton...Tom Green. WINTER WEATHER ADVISORY until 6 PM CST Monday FOR THE FOLLOWING ZONES: Crockett...Kimble...Mason...McCulloch...Menard...San Saba...Schleicher...Sutton. && $$ 25
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
939 PM CST SUN FEB 22 2015 .UPDATE... AS THE FIRST WAVE OF PRECIPITATION ENDS THIS EVENING...A LARGE AREA OF FREEZING DRIZZLE HAS DEVELOPED NORTH TO WEST OF THE DFW METROPLEX INCLUDING TARRANT COUNTY. 850 MB WINDS ARE OUT OF THE EAST OVERRUNNING THE COLD SURFACE AIR...BUT THEY HAVE PREVAILED FROM THIS DIRECTION MOST OF THE EVENING WITHOUT DRIZZLE DEVELOPING EARLIER IN THE NIGHT. THE RAP SHOWS A WEAK SHORTWAVE MOVING OVERHEAD WHICH IS LIKELY PROVIDING ADDITIONAL LIFT FOR THE DRIZZLE TO DEVELOP...IN COMBINATION WITH THE ISENTROPIC LIFT OVER THE COLD SURFACE LAYER. THE RAP SHOWS THIS SHORTWAVE MOVING EAST OF THE REGION BY MIDNIGHT AND EXPECT MOST OF THE DRIZZLE WILL END AROUND THAT TIME. HOWEVER...THE DRIZZLE IS ALREADY AND WILL CREATE A THIN LAYER OF ICE ON ELEVATED SURFACES...METAL OBJECTS...AND LIKELY BRIDGES AND OVERPASSES THAT ALREADY DO NOT HAVE ICE FROM THE FREEZING RAIN/SLEET EARLIER. IN ADDITION...RESIDUAL WATER REMAINING ON ROADWAYS TONIGHT MAY FREEZE OVERNIGHT AS TEMPERATURES FALL INTO THE 20S OVER A GOOD PORTION OF THE REGION. HOWEVER...THE STRONG WINDS WILL CONTINUE THROUGH THE OVERNIGHT HOURS WHICH MAY ALSO HELP TO EVAPORATE ANY WATER ON ROADWAYS...BUT NOT WHERE DRIZZLE IS OCCURRING. THE NEXT WAVE OF PRECIPITATION IS STILL EXPECTED TO ARRIVE BETWEEN 1-3 AM...MOVING IN FROM THE WEST OR SOUTHWEST. NO CHANGES ARE NEEDED TO THE CURRENT WARNING AND ADVISORY PRODUCTS...HOWEVER...IF THE NEXT ROUND OF PRECIPITATION IS SLIGHTLY FARTHER SOUTH THAN THE LATEST GUIDANCE SUGGESTS...IT IS POSSIBLE PORTIONS OF THE ADVISORY MAY HAVE TO BE UPGRADED TO A WARNING DUE TO HIGHER ACCUMULATIONS OF SLEET. UNFORTUNATELY WE WILL HAVE TO WAIT AND MONITOR THE RADAR TRENDS LATE TONIGHT AND EARLY MONDAY MORNING BEFORE BEING ABLE TO CONFIDENTLY MAKE THAT DECISION. 82/JLD && .AVIATION... /ISSUED 606 PM CST SUN FEB 22 2015/ SOME CHANGES WERE NECESSARY TO THE PREVIOUS TAF PACKAGE BASED ON HOW QUICKLY TEMPERATURES CONTINUE TO FALL. A MIX OR FREEZING RAIN/RAIN AND SLEET HAS ALREADY STARTED AT AFW AND FTW AND SHOULD START AT DFW...GKY...AND DAL IN THE NEXT FEW HOURS. (THE -SN IN THE GKY OB IS NOT CORRECT...IT IS ACTUALLY STILL LIGHT RAIN AS OF 6 PM). 00Z FWD SOUNDING SHOWS AN IMPRESSIVE WARM NOSE BETWEEN ABOUT 850 AND 700 MB WITH VERY UNSTABLE AIR ABOVE THIS INVERSION. THEREFORE...THE ATMOSPHERE IS CONDUCIVE TO CONVECTIVE ELEMENTS SO PERIODS OF HEAVY SLEET ALONG WITH THUNDER REMAIN POSSIBLE. FOR NOW WE WILL CHANGE PRECIP OVER TO A MIX OF FREEZING RAIN AND SLEET AT ALL METROPLEX TERMINAL BETWEEN NOW AND 02Z. IFR CEILINGS/VISIBILITY WILL PREVAIL THROUGH THE NIGHT WITH A NORTH WIND BETWEEN 14 AND 18 KNOTS ALONG WITH SOME HIGHER GUSTS. THE WINTER PRECIPITATION SHOULD DECREASE IN COVERAGE AND INTENSITY MID TO LATE EVENING WITH MAINLY LIGHT FREEZING DRIZZLE EXPECTED. A SECOND PIECE OF UPPER LEVEL ENERGY WILL MOVE ACROSS THE REGION BEGINNING EARLY MONDAY MORNING AND BRING ANOTHER ROUND OR MAINLY SLEET. THIS PRECIPITATION SHOULD CONTINUE OFF AND ON THROUGH THE MORNING MONDAY BEFORE ENDING FROM WEST TO EAST MONDAY AFTERNOON AND EVENING. IFR WITH OCCASIONAL MVFR CEILINGS/VISIBILITIES WILL PREVAIL THROUGH THE DAY MONDAYS WITH SLOWLY DECREASING NORTH WINDS. WACO SHOULD SEE IFR WITH OCCASIONAL MVFR CIGS/VISIBILITY TONIGHT WITH PERIODS OF DRIZZLE OR LIGHT RAIN. SOME LIGHT FREEZING DRIZZLE IS POSSIBLE AROUND SUNRISE MONDAY WITH LIGHT FREEZING RAIN AND SLEET POSSIBLE FROM ABOUT MID MORNING MONDAY THROUGH THE AFTERNOON. 79 && .PREV UPDATE... .UPDATE... HAVE UPDATED THE GRIDS FOR THE 00-06Z TIME FRAME BASED ON THE LATEST RADAR AND WEATHER TRENDS. A WINTER PRECIPITATION MIX OF RAIN/SLEET/FREEZING RAIN AND EVEN SOME SNOW IS OCCURRING GENERALLY NORTH OF A LINE FROM COMANCHE TO FORT WORTH TO BONHAM AND SURFACE TEMPERATURES IN THIS AREA RANGE FROM THE MID 20S IN THE NORTHWEST TO 32 DEGREES. SHORT TERM GUIDANCE CONTINUES TO SUGGEST THIS FIRST WAVE OF PRECIPITATION WILL END ACROSS THE REGION BETWEEN 9 PM - MIDNIGHT WITH SOME ISOLATED LIGHT LINGERING PRECIP AFTER THAT. THE NEXT WAVE OF PRECIPITATION WILL ARRIVE AROUND 2-3 AM IN OUR SOUTHWESTERN COUNTIES...MOVING NORTHEAST ACROSS THE REGION. ACCUMULATIONS OF ICE AND SLEET ARE ALREADY BEING REPORTED WITHIN THE HIGHLIGHTED AREA ABOVE AND IMPACTS TO TRAVEL ARE BEING REPORTED ALONG THE RED RIVER. AS FAR SOUTH AS THE NORTHERN PORTIONS OF THE METROPLEX...SOME SLUSHY ROADS AND SLICK BRIDGES AND OVERPASSES ARE ALREADY BEING REPORTED WHERE MODERATE TO HEAVY SLEET OCCURRED IN THE LAST 2-3 HOURS. AS TEMPERATURES CONTINUE TO FALL THROUGH THE NEXT FEW HOURS...TRAVEL WITHIN THE WARNING AREA ESPECIALLY WILL BECOME MORE DIFFICULT...NOT ONLY FROM THE FREEZING RAIN AND SLEET THAT IS OCCURING IN THIS AREA...BUT ANY WATER THAT IS LEFT ON THE ROADWAYS DUE TO THE RAIN EARLIER COULD POSSIBLY FREEZE RESULTING IN A THIN GLAZE OF ICE ON ROADWAYS. 82/JLD && .PREV DISCUSSION... /ISSUED 400 PM CST SUN FEB 22 2015/ ...SIGNIFICANT WINTER STORM TAKING SHAPE FOR OVERNIGHT AND EARLY MONDAY ACROSS NORTH TEXAS... .SIGNIFICANT FORECAST CHANGES... WINTER STORM WARNING START TIME HAS BEEN MOVED UP TO START NOW. WINTER WEATHER ADVISORY START TIME HAS BEEN MOVED UP TO 9PM. SLEET ACCUMULATIONS HAVE BEEN BUMPED UP SLIGHTLY ACROSS THE NORTHWEST PARTS OF THE CWA. ICE ACCUMULATIONS FROM FREEZING RAIN HAVE BEEN NUDGED UP SLIGHTLY BUT REMAIN BELOW WARNING CRITERIA FARTHER SOUTH. HOURLY TEMPERATURE TRENDS HAVE BEEN ADJUSTED TO REFLECT CURRENT POSITION OF COLDER AIR. HIGH TEMPERATURES ON MONDAY HAVE BEEN LOWERED BY 2-3 DEGREES. NO OTHER SIGNIFICANT FORECAST CHANGES THIS AFTERNOON. .TECHNICAL DISCUSSION... MUCH COLDER AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS AFTERNOON WITH SUB FREEZING TEMPERATURES NOW MOVING INTO THE NORTHWEST COUNTIES. PRECIPITATION HAS DIMINISHED IN INTENSITY ACROSS THESE AREAS WHICH SHOULD LIMIT ANY FREEZING RAIN POTENTIAL THROUGH THE EVENING HOURS. FARTHER EAST...A COLD RAIN WILL CONTINUE THROUGH THE EARLY EVENING AS THE FIRST WAVE OF LIFT MOVES TO THE NORTHEAST. TEMPERATURES ARE GENERALLY IN THE MID TO UPPER 30S AND LOWER 40S WHERE THIS PRECIPITATION IS OCCURRING SO NO FREEZING RAIN IS EXPECTED. SOME AREAS HAVE ALREADY PICKED UP CLOSE TO AN INCH OF RAIN BUT THIS INTENSITY WILL DIMINISH THROUGH EVENING. SIGNS OF THE SECOND WAVE OF ASCENT ARE ALREADY BEING INDICATED ON RADAR AND WATER VAPOR IMAGERY ACROSS WEST TEXAS. SOME AREAS OF PRECIPITATION HAVE ALREADY DEVELOPED BUT THIS SHOULD GENERALLY REMAIN SCATTERED OVER THE NEXT SEVERAL HOURS AS THE BETTER FORCING WILL ARRIVE DURING THE OVERNIGHT HOURS. WE ARE EXPECTED TO SEE A LULL IN THE PRECIPITATION LATER THIS EVENING THROUGH MIDNIGHT OR SO...BUT IT WONT BE COMPLETELY VOID OF ACTIVITY. THERE WILL LIKELY BE INTERMITTENT AREAS OF PRECIPITATION THAT DEVELOP IN POCKETS OF STRONGER FORCING THAT STREAM ACROSS NORTH TEXAS IN THE SOUTHWEST FLOW ALOFT. ANY PRECIPITATION THAT DEVELOPS LATE THIS EVENING COULD BE IN THE FORM OF A FREEZING RAIN/SLEET MIX ACROSS THE WEST AND NORTHWEST PARTS OF THE CWA. THE FREEZING LINE WILL SURGE SOUTH THIS EVENING ACROSS THE WESTERN COUNTIES AND IT WILL TAKE A LITTLE LONGER FARTHER EAST. IT SHOULD BE MOVING INTO THE METROPLEX BY 0Z OR A LITTLE LATER. BY 3-4AM...MOST AREAS WITH THE EXCEPTION OF THE SOUTHEAST COUNTIES SHOULD BE AT OR BELOW FREEZING. THE STRONGEST FORCING LOOKS LIKE IT WILL OVERSPREAD NORTH TEXAS IN THE 3-5AM TIMEFRAME WITH WIDESPREAD PRECIPITATION CONTINUING INTO THE MORNING HOURS ON MONDAY. THE COMPACT UPPER LOW SOUTH OF CALIFORNIA IS IN THE PROCESS OF EJECTING NORTHEAST NOW AND ANOTHER DISTURBANCE APPEARS TO BE EMBEDDED IN THE FLOW ACROSS NORTHWEST MEXICO. THESE SEEM TO BE THE FEATURES THAT REALLY PROVIDE THE FORCING FOR ASCENT LATE TONIGHT. RIGHT NOW... WE THINK THE HEAVIEST PRECIPITATION WILL OCCUR ALONG A LINE FROM NEAR EASTLAND TO DFW TO SHERMAN...AND AREAS NORTHWEST OF THERE THROUGH ABOUT 10AM ON MONDAY. LATEST HIGH RESOLUTION TTU-WRF AND 4KM NAM CONTINUE TO YIELD HIGH CONFIDENCE IN THE CURRENT FORECAST AS BOTH CONTINUE TO STRONGLY INDICATE CONVECTIVE ELEMENTS TO THE PRECIPITATION. SREF PLUMES OF MUCAPE AND ANALYSIS OF ALL AVAILABLE FORECAST SOUNDINGS INDICATE THAT ANYWHERE FROM 100-150J/KG OF ELEVATED INSTABILITY WILL BE PRESENT. THIS WILL SUPPORT THUNDERSLEET THROUGH THE MORNING HOURS. BURSTS OF SLEET CAN QUICKLY ACCUMULATE TO AN INCH OR MORE IN A SHORT PERIOD OF TIME. AS OF THIS AFTERNOON...WE THINK THAT MOST AREAS IN THE CURRENT WARNING WILL SEE BETWEEN 1/2 AND 1 INCH OF SLEET. FARTHER NORTHWEST...FROM FORT WORTH TO BOWIE...ACCUMULATIONS OF 1 TO 1 1/2 INCH OF SLEET WITH HEAVIER AMOUNTS WILL BE POSSIBLE. SOME LIGHT FREEZING RAIN WILL ALSO BE POSSIBLE THROUGH MORNING BUT ICE ACCUMULATIONS SHOULD GENERALLY BE LESS THAN 1/10 OF AN INCH. FARTHER SOUTH OF THE METROPLEX...WHERE THE CURRENT ADVISORY IS POSTED...THE WARM NOSE WILL BE A LITTLE MORE STOUT INITIALLY. THIS MAY KEEP PRECIPITATION ALL LIQUID AS OPPOSED TO SLEET. WITH TEMPERATURES FALLING BELOW FREEZING...SOME LIGHT ICING IS EXPECTED. THIS WILL BE WORST ON BRIDGES AND OVERPASSES. MOST OF THE PRECIPITATION SHOULD MOVE EAST OF THE AREA BY LATE MONDAY BUT WE WILL KEEP SOME LOW CHANCES IN THROUGH THE EVENING. SOME LIGHT FREEZING RAIN OR DRIZZLE MAY BE POSSIBLE DURING THIS TIME WITH LITTLE ADDITIONAL IMPACT. TEMPERATURES ON MONDAY ARE NOT EXPECTED TO RISE ABOVE FREEZING SO ANY ACCUMULATIONS OF SLEET/ICE WILL NOT MELT. THIS WILL RESULT IN CONTINUED TRAVEL PROBLEMS. TEMPERATURES ARE EXPECTED TO RISE ABOVE FREEZING BY MIDDAY TUESDAY. LITTLE CHANGES MADE TO THE END OF THE WEEK SYSTEM AS THERE IS STILL CONSIDERABLY MODEL UNCERTAINTY. WE HAVE CONTINUED WITH A RAIN/SNOW MIX LATE THURSDAY INTO LATE FRIDAY ACROSS MUCH OF THE AREA. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 26 27 25 39 31 / 80 100 20 20 10 WACO, TX 30 31 24 38 33 / 80 90 30 20 30 PARIS, TX 25 25 25 36 28 / 50 100 30 20 10 DENTON, TX 23 25 20 36 29 / 80 100 10 10 10 MCKINNEY, TX 26 26 23 38 28 / 70 100 20 10 10 DALLAS, TX 28 29 26 39 31 / 80 100 20 20 10 TERRELL, TX 29 29 25 37 30 / 70 100 20 20 10 CORSICANA, TX 30 30 26 38 32 / 70 90 30 20 20 TEMPLE, TX 31 32 25 40 34 / 90 90 30 20 30 MINERAL WELLS, TX 24 25 20 36 28 / 100 100 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR TXZ091>095- 100>107-115>123-129>134-141. WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR TXZ135-142>148- 156>162-174-175. && $$ 79/82
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
626 PM CST SUN FEB 22 2015 .DISCUSSION...UPDATE SENT TO REFLECT EXPIRATION OF RIP CURRENT ADVISORY. ROUGH SWELLS WILL CONTINUE TO GRADUALLY DIMINISH THROUGH THE EVENING AS A STRONG COLD FRONT APPROACHES THE REGION. ALSO MADE A FEW MINOR EDITS TO HOURLY WIND AND TEMPERATURE FORECAST BASED OFF FROPA POSITIONING AND EXTRAPOLATION. FRONT SHOULD START TO ACCELERATE SOUTH THIS EVENING AS NOCTURNAL COOLING OCCURS AHEAD OF THE FRONT. && .PREV DISCUSSION... /ISSUED 523 PM CST SUN FEB 22 2015/ DISCUSSION...UPDATED FOR 00Z TAF FORECAST. AVIATION...COLD FRONT CURRENTLY JUST TO THE NORTH OF SOUTH TEXAS WILL MOVE THROUGH ALL TAF LOCATIONS BEFORE MIDNIGHT. EXPECT A GUSTY NORTH WIND TO DEVELOP BEHIND THE FRONT. AHEAD OF THE FRONT IFR TO POTENTIALLY LIFR CONDITIONS WILL DEVELOP...AND REMAIN THROUGH THE NIGHT. BY DAYBREAK...SHOULD IMPROVE CONDITIONS TO MVFR WHERE THEY WILL REMAIN THROUGH THE DAY. LIGHT RAIN WILL BE POSSIBLE AT TIMES AS WELL. PREV DISCUSSION... /ISSUED 348 PM CST SUN FEB 22 2015/ SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...FRONTAL BOUNDARY HAS REMAINED STALLED JUST NORTH OF THE FORECAST AREA THIS AFTERNOON. LATEST MSAS ANALYSIS SHOWS AREAS OF STRONG PRESSURE RISES BEHIND THE FRONT SHIFTING TOWARD CENTRAL TEXAS INTO THE HILL COUNTRY. THIS CORRESPONDS TO LOCATION OF TEMPERATURES IN THE 40S. EXPECT THE FRONT WILL BEGIN TO ADVANCE SOUTHWARD LATE THIS AFTERNOON AND SURGE TO THE SOUTH THIS EVENING. WENT CLOSE TO THE SREF/HRRR/3KM TECH WRF AND ECMWF WITH TIMING OF THE FRONT...PUSING INTO THE COASTAL WATERS BETWEEN 04-06Z. HRRR SHOWS THE POSSIBILITY OF CONVECTION FORMING OVER THE HIGH TERRAIN IN NORTHEAST MEXICO AHEAD OF THE COLD FRONT AND MOVING SOUTHEAST TOWARD THE RIO GRANDE. BUT EXPECT AIR MASS TO BE CAPPED AND WILL NOT MENTION THUNDER IN THE FORECAST AT THIS TIME. THERE WILL BE A PERIOD OF FOG POSSIBLE ALONG THE COAST BEFORE FRONTAL PASSAGE. MODEST ISENTROPIC LIFT WILL OCCUR IN THE 285-300K LAYER LATE TONIGHT THROUGH MONDAY. WILL SHOW POPS AROUND 50 PERCENT FOR TONIGHT WITH LIKELY POPS FOR MONDAY. LOW LEVEL COLD AIR ADVECTION WILL CONTINUE DURING THE DAY MONDAY. DIURNAL TREND MAY BE SLOWLY DOWNWARD MOST OF THE DAY. ISENTROPIC LIFT WILL DIMINISH FROM WEST TO EAST MONDAY NIGHT WITH DECREASING POPS. LOW TEMPS WILL REACH DOWN INTO THE 30S MONDAY NIGHT BUT EXPECT IT WILL REMAIN ABOVE FREEZING AT THIS TIME. MARINE (TONIGHT THROUGH MONDAY NIGHT)...COLD FRONT WILL REACH THE BAYS AND NEARSHORE WATERS A LITTLE EARLIER THIS EVENING. PUT THE START TIME FOR THE SCA FOR TONIGHT AT 04Z. STRONG NORTH TO NORTHEAST WINDS WILL PERSIST INTO MONDAY NIGHT FOR THE GULF WATERS. EXTENDED SCA FOR THE BAYS THROUGH THE DAY MONDAY AND MONDAY EVENING FOR THE GULF WATERS. LONG TERM (TUESDAY THROUGH SATURDAY NIGHT)...ZONAL FLOW ACROSS THE SOUTHERN CONUS THIS FORECAST PERIOD WILL RESULT IN A MIX OF WEATHER CONDITIONS FOR THIS UPCOMING WEEK. ISENTROPIC LIFT WILL MAINTAIN CHC OF LIGHT RAIN THROUGH EARLY WEDNESDAY BEFORE DRIER AIR MOVES IN AND A SLIGHT WARMING TREND COMMENCES. TEMPS ON TUE WILL STRUGGLE TO GET OUT OF THE 40S DUE TO THICK CLOUD COVER...ALTHOUGH A FEW 50S ARE POSSIBLE ALONG THE COAST AND OUT WEST. NEXT REINFORCING SURGE OF HIGH PRESSURE ARRIVES EARLY WEDNESDAY WITH SCA CONDITIONS OCCURING ON WED...HOWEVER...ABUNDANT SUNSHINE WILL ALLOW TEMPS TO REACH THE 60S BOTH WED-THU. NEXT FRONT ARRIVES LATE THURSDAY WITH A MODERATE OFFSHORE FLOW DEVELOPING IN ITS WAKE. THE FRONT WILL DROP TEMPS BACK INTO THE 40S-50S FOR FRIDAY BENEITH OVC SKIES. COULD BE A FEW SHOWERS AS MOIST SOUTHERLY LOW LVL FLOW OVERRIDES THE COOL BOUNDARY LAYER. THE COOL AIR WONT LAST LONG AS A DEEP TROUGH BEGINS TO TAKE SHAPE ACROSS THE DESERT SW DRAWING A WARM FRONT BACK THROUGH THE AREA SAT. TEMPS ON SAT WILL WARM BACK INTO THE LOW TO MID 60S SAT WITH 70S EXPECTED SUNDAY. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 47 48 38 50 43 / 50 70 40 20 30 VICTORIA 43 44 35 46 38 / 50 70 40 20 40 LAREDO 46 46 39 54 44 / 50 50 20 10 10 ALICE 45 46 37 50 41 / 50 70 40 20 30 ROCKPORT 47 50 39 50 43 / 50 70 40 30 40 COTULLA 42 43 35 50 40 / 50 50 30 10 10 KINGSVILLE 48 48 37 50 43 / 50 70 40 20 30 NAVY CORPUS 49 51 39 51 45 / 50 70 40 30 40 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO MIDNIGHT CST MONDAY NIGHT FOR THE FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM CST MONDAY FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR. && $$ UPDATE...HART/79
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
523 PM CST SUN FEB 22 2015 .DISCUSSION...UPDATED FOR 00Z TAF FORECAST. && .AVIATION...COLD FRONT CURRENTLY JUST TO THE NORTH OF SOUTH TEXAS WILL MOVE THROUGH ALL TAF LOCATIONS BEFORE MIDNIGHT. EXPECT A GUSTY NORTH WIND TO DEVELOP BEHIND THE FRONT. AHEAD OF THE FRONT IFR TO POTENTIALLY LIFR CONDITIONS WILL DEVELOP...AND REMAIN THROUGH THE NIGHT. BY DAYBREAK...SHOULD IMPROVE CONDITIONS TO MVFR WHERE THEY WILL REMAIN THROUGH THE DAY. LIGHT RAIN WILL BE POSSIBLE AT TIMES AS WELL. && .PREV DISCUSSION... /ISSUED 348 PM CST SUN FEB 22 2015/ SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...FRONTAL BOUNDARY HAS REMAINED STALLED JUST NORTH OF THE FORECAST AREA THIS AFTERNOON. LATEST MSAS ANALYSIS SHOWS AREAS OF STRONG PRESSURE RISES BEHIND THE FRONT SHIFTING TOWARD CENTRAL TEXAS INTO THE HILL COUNTRY. THIS CORRESPONDS TO LOCATION OF TEMPERATURES IN THE 40S. EXPECT THE FRONT WILL BEGIN TO ADVANCE SOUTHWARD LATE THIS AFTERNOON AND SURGE TO THE SOUTH THIS EVENING. WENT CLOSE TO THE SREF/HRRR/3KM TECH WRF AND ECMWF WITH TIMING OF THE FRONT...PUSING INTO THE COASTAL WATERS BETWEEN 04-06Z. HRRR SHOWS THE POSSIBILITY OF CONVECTION FORMING OVER THE HIGH TERRAIN IN NORTHEAST MEXICO AHEAD OF THE COLD FRONT AND MOVING SOUTHEAST TOWARD THE RIO GRANDE. BUT EXPECT AIR MASS TO BE CAPPED AND WILL NOT MENTION THUNDER IN THE FORECAST AT THIS TIME. THERE WILL BE A PERIOD OF FOG POSSIBLE ALONG THE COAST BEFORE FRONTAL PASSAGE. MODEST ISENTROPIC LIFT WILL OCCUR IN THE 285-300K LAYER LATE TONIGHT THROUGH MONDAY. WILL SHOW POPS AROUND 50 PERCENT FOR TONIGHT WITH LIKELY POPS FOR MONDAY. LOW LEVEL COLD AIR ADVECTION WILL CONTINUE DURING THE DAY MONDAY. DIURNAL TREND MAY BE SLOWLY DOWNWARD MOST OF THE DAY. ISENTROPIC LIFT WILL DIMINISH FROM WEST TO EAST MONDAY NIGHT WITH DECREASING POPS. LOW TEMPS WILL REACH DOWN INTO THE 30S MONDAY NIGHT BUT EXPECT IT WILL REMAIN ABOVE FREEZING AT THIS TIME. MARINE (TONIGHT THROUGH MONDAY NIGHT)...COLD FRONT WILL REACH THE BAYS AND NEARSHORE WATERS A LITTLE EARLIER THIS EVENING. PUT THE START TIME FOR THE SCA FOR TONIGHT AT 04Z. STRONG NORTH TO NORTHEAST WINDS WILL PERSIST INTO MONDAY NIGHT FOR THE GULF WATERS. EXTENDED SCA FOR THE BAYS THROUGH THE DAY MONDAY AND MONDAY EVENING FOR THE GULF WATERS. LONG TERM (TUESDAY THROUGH SATURDAY NIGHT)...ZONAL FLOW ACROSS THE SOUTHERN CONUS THIS FORECAST PERIOD WILL RESULT IN A MIX OF WEATHER CONDITIONS FOR THIS UPCOMING WEEK. ISENTROPIC LIFT WILL MAINTAIN CHC OF LIGHT RAIN THROUGH EARLY WEDNESDAY BEFORE DRIER AIR MOVES IN AND A SLIGHT WARMING TREND COMMENCES. TEMPS ON TUE WILL STRUGGLE TO GET OUT OF THE 40S DUE TO THICK CLOUD COVER...ALTHOUGH A FEW 50S ARE POSSIBLE ALONG THE COAST AND OUT WEST. NEXT REINFORCING SURGE OF HIGH PRESSURE ARRIVES EARLY WEDNESDAY WITH SCA CONDITIONS OCCURING ON WED...HOWEVER...ABUNDANT SUNSHINE WILL ALLOW TEMPS TO REACH THE 60S BOTH WED-THU. NEXT FRONT ARRIVES LATE THURSDAY WITH A MODERATE OFFSHORE FLOW DEVELOPING IN ITS WAKE. THE FRONT WILL DROP TEMPS BACK INTO THE 40S-50S FOR FRIDAY BENEITH OVC SKIES. COULD BE A FEW SHOWERS AS MOIST SOUTHERLY LOW LVL FLOW OVERRIDES THE COOL BOUNDARY LAYER. THE COOL AIR WONT LAST LONG AS A DEEP TROUGH BEGINS TO TAKE SHAPE ACROSS THE DESERT SW DRAWING A WARM FRONT BACK THROUGH THE AREA SAT. TEMPS ON SAT WILL WARM BACK INTO THE LOW TO MID 60S SAT WITH 70S EXPECTED SUNDAY. && .PRELIMINARY POINT TEMPS/POPS... CORPUS CHRISTI 47 48 38 50 43 / 50 70 40 20 30 VICTORIA 43 44 35 46 38 / 50 70 40 20 40 LAREDO 46 46 39 54 44 / 50 50 20 10 10 ALICE 45 46 37 50 41 / 50 70 40 20 30 ROCKPORT 47 50 39 50 43 / 50 70 40 30 40 COTULLA 42 43 35 50 40 / 50 50 30 10 10 KINGSVILLE 48 48 37 50 43 / 50 70 40 20 30 NAVY CORPUS 49 51 39 51 45 / 50 70 40 30 40 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...RIP CURRENT RISK UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING ZONES: ARANSAS...CALHOUN...KLEBERG...NUECES. GM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO MIDNIGHT CST MONDAY NIGHT FOR THE FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 PM CST MONDAY FOR THE FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR. && $$ PZ/83...AVIATION
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1106 AM CST SAT FEB 21 2015 .DISCUSSION... SEE 18Z AVIATION DISCUSSION. && .AVIATION... FCST SOUNDINGS CONTINUE TO ADVERTISE MVFR CIGS WILL DEVELOP THIS AFTN ALONG WITH SCT SHRA. SHRAS HAVE INCREASED IN COVERAGE OVER THE LAST HOUR. IFR/LIFR CIGS EXPECTED TO DEVELOP OVERNIGHT AND LINGER THROUGH MUCH OF SUNDAY MORNING. PW VALUES INCREASE RATHER SIGNIFICANTLY AFTER 18Z SO ADDED VCSH TO THE IAH TAF FOR SUNDAY AFTN. THERE IS ALSO SOME POTENTIAL FOR SEA FOG TO DEVELOP TONIGHT. LATEST HRRR SHOWS SEA FOG DEVELOPING BETWEEN 00-03Z AND GRADUALLY MOVING INLAND OVERNIGHT. 43 && .PREV DISCUSSION... /ISSUED 1039 AM CST SAT FEB 21 2015/ UPDATE... SURFACE LOW OVER THE ARKLATEX WITH ITS ASSOCIATED TROUGH/COLD FRONTAL BOUNDARY STRETCHING SOUTHWEST ACROSS AND PARALLEL TO THE BALCONES ESCARPMENT. LIGHT AND WIDELY SCATTERED AREAS OF LIGHT SHOWERS FORMING JUST DOWNSTREAM OF THE BOUNDARY AND MOVING NORTHEAST (CAUGHT UP IN A WEAKENING LLJ) FROM ROUGHLY THE MATAGORDA BAY AREA INTO THE PINEY WOODS. OVERCAST STRATUS AND COASTAL HAZE IN THIS RELATIVELY MOIST ENVIRONMENT...SOUTHWEST TO SOUTH WINDS PULLING IN MID-60 DEW POINT AIR FROM THE GULF. WEB CAMERAS ARE SHOWING DENSE SEA FOG APPROACHING THE MATAGORDA BAY SHORELINE THIS MORNING. PATCHY BECOMING AREAS OF SEA FOG WILL LIKELY AFFECT THE LOCAL BAYS AND NEARSHORE WATERS THROUGH SUNDAY MORNING...OR UNTIL THE FRONT MAKES ITS WAY OFF THE UPPER TEXAS COAST TOMORROW AFTERNOON. SOUTHEAST TEXAS WILL REMAIN IN THE WARM SECTOR THROUGH EARLY EVENING. THUS...TODAY`S FORECAST IS FOR LITTLE CHANGE IN THESE CURRENT CONDITIONS OF OVERCAST WITH BRIEF PERIODS OF VERY LIGHT RAIN TO OCCANSIONAL DRIZZLE /SPRINKLES...AFTERNOON TEMPERATURES BRIEFLY ACHIEVING THE LOWER TO MIDDLE 70S. THE FRONTAL BOUNDARY IS TIMED TO REACH THE NORTHWESTERN COUNTIES AROUND SUNSET TONIGHT...THE METRO AREA DURING THE PRE-DAWN SUNDAY HOURS...AND THEN STALL OUT ALONG THE COASTAL COUNTIES THROUGH SUNDAY AFTERNOON. A 1050-ISH MB LARGE HIGH DROPPING OUT OF CENTRAL CANADA LATE TOMORROW WILL AID IN PUSHING THE FRONT OFF THE COAST BY MIDNIGHT MONDAY. INCREASING NORTHEAST WINDS...WITH MID-LEVEL SOUTH-SOUTHWEST WINDS...WILL ENHANCE ISENTROPIC LIFT THROUGH TUESDAY. COLD AIR ADVECTION KICKING IN EARLY MONDAY MORNING WILL BE THE IMPETUS TO AN OVERCAST AND COLD DAY IN THE 30S AND 40S. THIS OVERRUNNING SCENARIO OF WARM MID-LEVEL DROPLETS FALLING THROUGH A VERY SHALLOW SUB-FREEZING SURFACE LAYER WILL INCREASE THE PROBABILITY FOR THE DEVELOPMENT OF FREEZING RAIN ACROSS THE NORTHERN THIRD OF THE CWA FROM EARLY MONDAY EVENING THROUGH TUESDAY MORNING. 31 PREV DISCUSSION... /ISSUED 453 AM CST SAT FEB 21 2015/ DISCUSSION... AREA RADAR SHOW SHOWERS STREAMING NORTH WITHIN A 40-50KT LLJ. TEMPS ARE HOLDING STEADY IN THE MID 60S WITH DECENT WINDS MIXING DOWN AND EVEN WIND GUSTS OF 30KTS AS OBSERVED AT KUTS AT 10Z. SFC ANALYSIS HAS SFC LOW NEAR DFW METROPLEX WITH WARM FRONT EXTENDING ENE FROM THE LOW TOWARDS THE ARKLATEX AND MID MISS RIVER VALLEY. COLD FRONT IS DEVELOPING OVER N TX INTO THE TX PANHANDLE. WARM SECTOR AIRMASS SUPPORTS DEWPOINTS IN THE LOW 60S WITH MID 60S IN THE GULF. LLJ AXIS BENDS FROM THE UPPER TX COAST TOWARDS MISS RIVER VALLEY HELPING TO FOCUS CONVECTION OVER N ARK INTO W TN. UPPER LEVEL ANALYSIS AND WATER VAPOR IMAGERY SHOW THIS CONVECTION HAVING SUPPORT FROM AN INITIAL SHORTWAVE AND A SECOND WAVE OVER KS/OK. ANOTHER STRONGER WAVE REMAINS BACK OVER THE INTER-MTN WEST. A CUTOFF LOW REMAINS OUT IN THE PACIFIC WHICH WILL HAVE A ROLE IN RAIN CHANCES FOR EARLY NEXT WEEK. SFC LOW OVER N TX THIS MORNING SHOULD QUICKLY MOVE EAST WITH COLD FRONT PUSHING INTO TX. AHEAD OF THE FRONT THE WARM SECTOR WILL BE MARGINALLY UNSTABLE WITH MAYBE 500-1000 J/KG OF CAPE. FORECAST SOUNDINGS STILL SHOW A DECENT CAP FROM THE EML AROUND 800MB. GFS IS SHOWING A STRONGER CAP THAN THE NAM WHICH WEAKENS THE CAP. THINK BEST CHANCES FOR ANY STRONG/SEVERE STORMS WILL BE EAST OF THE AREA INTO LA AND THAT IS STILL QUITE UNCERTAIN. FORECAST WILL MAINTAIN A MENTION OF ISO TSRA BUT NOT VERY CONFIDENT. SHOWERS UNDER THE CAP WILL BE MAIN PRECIP MODE. THE OTHER CONCERN FOR TODAY WILL BE THE DEVELOPMENT OF SEA FOG FOR THE NEAR SHORE WATERS OF THE UPPER TX COAST AND MATAGORDA/GALVESTON BAYS. WITH DEWPOINTS INCREASING AND WATER TEMPS IN THE UPPER 50S...COULD GET FOG FORMATION TONIGHT INTO SUN AS WINDS DECREASE. TIMING THE FROPA CONTINUES TO BE A CHALLENGE. NAM/GFS BOTH HAVE THE FRONT REACHING COLLEGE STATION TO CROCKETT AROUND 00-03Z SUN. THE ECMWF LOOKS TO BE MAYBE 3 HRS BEHIND THAT WITH FROPA. THE FRONT THEN SLOWS AND MAYBE REACHES HOUSTON METRO AROUND 09-12Z SUN. THE NAM IS MORE PROGRESSIVE THAN THE GFS/ECMWF AT THIS POINT. THE ECMWF DOES NOT REALLY PUSH THE FRONT OFF THE COAST UNTIL MAYBE 00-06Z MON. GFS SEEMS TO STALL THE FRONT ALONG I-10 DURING THE DAY SUN AND THEN OFF THE COAST WITH SIMILAR TIMING. THE NAM ALSO STALLS THE FRONT BUT MORE RIGHT ALONG THE COAST AND THEN PUSHES IT COMPLETELY THROUGH SIMILAR TO THE GFS/ECMWF. A LEAD SHORTWAVE TROUGH MOVES OVER THE AREA FROM THE UPPER LOW IN THE PACIFIC SUN AFTERNOON. THIS INCREASES ISENTROPIC LIFT OVER THE FRONT AND LEAD TO BETTER RAIN CHANCES. ANOTHER WEAK WAVE MOVES OVER MONDAY BUT SEEMS THAT ISENTROPIC LIFT INCREASE MORE DUE TO INCREASING JET OVER THE MAIN 850MB FRONT OVER N TX. RAIN CHANCES GO FROM MAINLY 40 POPS ON SUNDAY TO 50 PERCENT ON MONDAY. PRECIP LOOKS TO CONTINUE FALLING MON NIGHT INTO TUE. THIS ALSO CORRESPONDS TO WHEN THE COLDEST AIR WILL BE OVER SE TX. TEMPS SHOULD NOT INCREASE MUCH MONDAY AND IN FACT COULD SLOWLY DROP DURING THE DAY. TEMP PROFILES AT CLL AND LFK ON GFS BUFR SOUNDINGS SHOW A SUB FREEZING LAYER MAYBE 1500-2000FT THICK DEVELOP NEAR THE SFC WITH A STRONG WARM NOSE AT 850MB 00Z TUE THROUGH 15Z TUE. SUB FREEZING LAYER IS THICKER AT LFK. DURING THE SAME TIME THE NAM IS NOT AS COLD AS THE GFS BUT PROFILES STILL SUPPORT FREEZING RAIN AT CLL THROUGH LFK. THERE DOES NOT SEEM TO BE ENOUGH SEEDING ALOFT TO SUGGEST SLEET PLUS THE WARM NOSE IS TOO STRONG AND LIKELY MELT ANY SLEET/SNOW FALLING THROUGH THE COLUMN. PRECIP AMOUNTS FROM 00Z TO 15Z TUE MAY PUSH AT MOST A TENTH OF AN INCH WHICH WILL BE CLOSE TO ICE ACCUMULATION CRITERIA OF A WINTER STORM WARNING. THE MAIN ISSUE WITH THE COLDER GFS IS THAT RAIN WILL LIKELY BE FALLING DURING THIS TIME WHICH COULD ACT TO WARM THE PROFILE SINCE THERE WILL BE NO EVAPORATION. THIS MEANS TEMPS COULD POTENTIALLY REMAIN ABOVE FREEZING. THAT SAID COLD ADVECTION IN SHALLOW COLD AIRMASS LIKE THIS IS DIFFICULT TO DETERMINE. SHOULD FREEZING RAIN DEVELOP MON NIGHT INTO TUE...IT STILL LOOKS LIKE THE MAIN AREAS IMPACTED WILL BE FROM CALDWELL TO COLLEGE STATION TO HUNTSVILLE AND LIVINGSTON NORTHWARD. AREAS FROM MADISONVILLE TO CROCKETT OVER TO LUFKIN WILL LIKELY HAVE THE BEST CHANCES OF FREEZING RAIN AND ICE ACCUMULATIONS. THIS MATCHES WELL WITH WPC THINKING IN THEIR FREEZING RAIN PROBABILITIES. AT THIS TIME ICE ACCUMULATION SHOULD BE LESS THAN A TENTH OF AN INCH BUT THAT COULD CHANGE. NOTE THAT AREAS SOUTH OF BRENHAM TO CLEVELAND LINE SHOULD REMAIN WARM ENOUGH FOR PRECIP TO BE RAIN. NO IMPACTS ARE EXPECTED FOR THE HOUSTON METRO AREA AT THIS TIME. TROUGHING CURRENTLY OVER THE INTER-MTN WEST DOES DEVELOP INTO A CLOSED LOW OVER THE GREAT BASIN BY SUN NIGHT INTO MON. THIS LOW THEN BEGINS TO MOVE ACROSS THE S ROCKIES IN RESPONSE TO ANOTHER UPPER LOW MOVING INTO THE GREAT LAKES ON TUE. THE ECMWF AND GFS ARE IN PRETTY GOOD AGREEMENT WITH THE SYSTEM MOVING OVER TX WITH A POS TILT ON WED. THIS SHOULD PROVIDE THE EASTERN HALF OF THE AREA WITH HIGHER RAIN CHANCES WHICH MOVE EAST QUICKLY. THE TROUGH DOES BECOME MORE NEG TILT WED NIGHT INTO THUR IMPACTING THE SE U.S. AS THE SYSTEM MOVES EAST ANOTHER COLD FRONT BEGINS TO MOVE SOUTH INTO TX. THIS FRONT SHOULD REACH THE AREA THUR/FRI OF THE COMING WEEK WITH ANOTHER TROUGH FORMING OVER THE S ROCKIES. THIS MAY SET THE STAGE FOR ANOTHER OVERRUNNING PRECIP EVENT NEXT WEEKEND. 39 MARINE... STRONG ONSHORE FLOW AND ELEVATED SEAS CONTINUE ACROSS THE COASTAL WATERS THIS MORNING. WINDS WILL BEGIN TO EASE LATE TODAY WITH SEAS LOWERING OVERNIGHT. HAVE EXTENDED THE CURRENT SMALL CRAFT ADVISORY FOR ALL COASTAL WATERS THROUGH MIDNIGHT TONIGHT. SEA FOG DEVELOPMENT IS POSSIBLE OVERNIGHT INTO SUNDAY MORNING. AFTER A BRIEF RESPITE A STRONG COLD FRONT WILL MOVE OFFSHORE ON SUNDAY BRINGING INCREASED NORTHEAST WINDS AND BUILDING SEAS. ELEVATED WINDS AND SEAS WILL PERSIST THROUGH AT LEAST TUESDAY IN THE WAKE OF THE FRONT WITH ADVISORY AND CAUTION FLAGS LIKELY. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 74 51 57 37 38 / 30 20 50 40 50 HOUSTON (IAH) 75 58 65 39 42 / 30 30 40 40 50 GALVESTON (GLS) 69 60 66 44 46 / 20 20 30 40 50 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY. SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM. && $$ DISCUSSION...31 AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
529 PM CST SUN FEB 22 2015 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 231 PM CST SUN FEB 22 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH PRESSURE DRIFTING SOUTHEAST OVER THE NORTHERN GREAT PLAINS EARLY THIS AFTERNOON. THOUGH COLD ADVECTION IS ONGOING...HEATING HAS SERVED TO STEEPEN LOW LEVEL LAPSE RATES...WHICH TRIGGERED A CU FIELD TO FORM LATE IN THE MORNING. DRY AIR IS WINNING OUT THIS AFTERNOON AS EVIDENT BY THE CU FIELD DIMINISHING. ONLY CLEAR AND BITTERLY COLD CONDITIONS EXIST UPSTREAM...SO FORECAST CONCERNS INCLUDE TEMPS AND WIND CHILLS THROUGH MONDAY. TONIGHT...STRONG ARCTIC HIGH PRESSURE WILL BE SLIDING SOUTHEAST FROM THE NORTHERN GREAT PLAINS TO CENTRAL IOWA. LOSS OF DIURNAL HEATING WILL CAUSE ANY LINGERING CU TO DISSIPATE BY EARLY THIS EVENING...WHICH WILL LEAVE CLEAR SKIES FOR MUCH OF THE NIGHT. BECAUSE THE ARCTIC HIGH WILL DROP SOUTHWEST OF THE REGION...BOTH STATISTICAL AND NUMERICAL GUIDANCE POINT TOWARDS WINDS REMAINING IN THE 5 TO 10 KT RANGE THIS EVENING...BEFORE DIMINISHING SOME OVERNIGHT. SOME POTENTIAL FOR DECOUPLING OVER N-C WISCONSIN AS BOUNDARY LAYER WINDS LIGHTEN. AS A RESULT...THINK TEMPERATURES HAVE A CHANCE TO TUMBLE LATE TONIGHT. THIS MAKES FOR A DILEMMA IN TERMS OF HEADLINE DECISIONS. IF WINDS REMAIN IN THE 4-5 KT RANGE...SOME PLACES LIKE ANTIGO AND RHINELANDER COULD REACH WIND CHILL WARNING CRITERIA FOR A PERIOD LATE TONIGHT INTO MONDAY MORNING. THINK WARNING CONDITIONS WILL NOT BE WIDESPREAD ENOUGH DUE TO WINDS DROPPING OFF. SO WILL STICK WITH THE ADVISORY THROUGH THE NIGHT AND CONTINUE TO MENTION THAT SOME SPOTS WILL HIT WARNING CRITERIA. IF WINDS DO DROP OFF...TEMPS 25 TO 30 BELOW ARE POSSIBLE. MONDAY...HIGH PRESSURE WILL BE DRIFTING TO THE MID-MISSISSIPPI VALLEY WHILE THE NEXT CLIPPER WILL REACH NORTHERN MINNESOTA LATE IN THE AFTERNOON. A TIGHTENING PRESSURE GRADIENT BETWEEN THESE FEATURES WILL CAUSE WINDS TO SWING AROUND TO THE SOUTHWEST AND BECOME GUSTY IN THE AFTERNOON. BUT THE SOUTHWEST WINDS WILL ALSO HELP MODERATE THE BITTERLY COLD AIRMASS. WIND CHILLS WILL BE WARMING ABOVE ADVISORY CRITERIA BY LATE IN THE MORNING SO THE ENDING TIME LOOKS ABOUT RIGHT. THOUGH CIRRUS WILL BE INCREASING IN THE AFTERNOON...HIGHS WILL WARM INTO THE UPPER SINGLE DIGITS TO THE LOWER TEENS. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 231 PM CST SUN FEB 22 2015 OVERALL UPPER LEVEL PATTERN CONSISTING OF A WESTERN RIDGE AND EASTERN TROUGH WILL REMAIN FOR MOST OF THE PERIOD...ALTHOUGH THERE ARE HINTS THAT THE WESTERN RIDGE MAY REORGANIZE FURTHER WEST OVER THE PACIFIC WHILE FLOW OVER THE UNITED STATES TAKES ON MORE OF AN APPEARANCE OF SPLIT FLOW. THIS CHANGE DOES NOT LOOK LIKE IT WILL DO MUCH TO REVERSE OUR TREND OF SEEING TEMPS WELL BELOW NORMAL. FOR NOW...ONLY TUESDAY LOOKS TO SEE HIGHS RELATIVELY NEAR NORMAL...WITH A RETURN TO COLD WEATHER AFTER A FRONT MOVES THROUGH. THE PRIMARY CHANCE FOR MEASURABLE SNOW LOOKS TO BE MONDAY NIGHT AND TUESDAY AS A LOW PRESSURE PASSES NORTH THROUGH ONTARIO...WITH AN ATTACHED COLD FRONT PUSHING ACROSS THE AREA ONCE AGAIN. GUIDANCE CONTINUES TO LIKE OUR FAR NORTH FOR THE BEST CHANCE AND AMOUNTS OF SNOW...TO BE EXPECTED AS THE LOW PASSES SOME DISTANCE TO OUR NORTH AND EAST. HOWEVER...THE GFS AND TO SOME EXTENT THE GEM PROVIDE BETTER MOISTURE AND LIFT...AND BRING AN INCH OR TWO OF SNOW DOWN THROUGH A LARGE PORTION OF THE NORTHEAST QUARTER OF WISCONSIN. IT IS WORTH NOTING THAT THE GFS ENSEMBLE CONTINUES TO NOT BE AS ENAMORED OF THIS IDEA AS THE DETERMINISTIC RUN. IN GENERAL WILL FOLLOW SUIT...PUTTING THE HIGHEST POPS AND ACCUMULATIONS IN FAR NORTHERN WISCONSIN...BUT WILL PAY SOME DEFERENCE TO THE NORTH AMERICAN MODELS AND THEIR PLAUSIBLE...IF NOT AS CONVINCING...IDEA OF MORE SNOW FURTHER TO THE SOUTH AND WEST WITH CHANCE POPS TUESDAY MORNING. ALONG WITH THIS SNOW...OUR POSITION BETWEEN THIS ONCOMING LOW AND THE HIGH RESPONSIBLE FOR OUR MOST RECENT COLD PLUNGE WILL RESULT IN GUSTY SOUTHWEST WINDS MONDAY NIGHT INTO TUESDAY. THIS COULD CREATE SOME BLOWING AND DRIFTING OF ANY SNOW THAT MAY FALL...EVEN IF AMOUNTS ARE NOT PARTICULARLY HIGH. GUIDANCE IS UNANIMOUS IN STRONG 50 TO 65 KNOT WINDS AT RELATIVELY LOW ALTITUDE VERY EARLY TUESDAY MORNING. SOUNDINGS IN BUFKIT SHOW POTENTIAL GUSTS TO 20-30 KTS...AND GUSTS EVEN A LITTLE HIGHER ARE NOT OUT OF THE QUESTION...THOUGH THIS SCENARIO WOULD NEED BETTER MIXING TO COME TO FRUITION. AFTERWARDS...HIGH PRESSURE SETTLES OVER THE AREA BRINGING DRY WEATHER THROUGH SATURDAY. IN WHAT SURELY IS BEGINNING TO SOUND ALL TOO FAMILIAR...WE WILL SEE ANOTHER SHOT OF WELL BELOW NORMAL TEMPERATURES. THE COLDEST PERIOD LOOKS TO BE TUESDAY NIGHT THROUGH THURSDAY. HIGHS ON WEDNESDAY LOOK TO BE MIRED IN THE SINGLE DIGITS FOR MOST...WITH SUBZERO LOWS ON TAP TUESDAY AND WEDNESDAY NIGHT. A SLOW MODERATION IN TEMPERATURES IS EXPECTED THROUGH THE WEEKEND. ANOTHER CHANCE FOR PRECIPITATION EMERGES DURING THE WEEKEND...BUT WITH A GOOD BIT OF UNCERTAINTY IN THE NATURE OF THE UPPER FLOW...WILL NOT SPECULATE ON THE DETAILS FOR NOW. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 527 PM CST SUN FEB 22 2015 VFR CONDITIONS TO PREVAIL TNGT THRU MON AS A LARGE AREA OF HI PRES MOVES FROM THE NRN PLAINS SE TOWARD THE OHIO RIVER VALLEY. WINDS ARE FCST TO SLOWLY BACK FROM NW THIS EVENING...TO WEST MON MORNING... TO SW MON AFTERNOON. THE PRES GRADIENT WL GRADUALLY TIGHTEN BY MON AFTERNOON BETWEEN THE HI PRES TO OUR SOUTH AND AN AREA OF LOW PRES RESIDING WELL TO OUR NORTH. WIND GUSTS COULD APPROACH 20 KTS BY LATE MON. NE WI WL ALSO SEE AN INCREASE IN MID/HI CLOUDS ON MON AHEAD OF A CDFNT THAT IS FCST TO MOVE THRU THE AREA ON TUE. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 10 AM CST MONDAY FOR WIZ013-020>022-031-037>040-045-048>050-073-074. WIND CHILL ADVISORY UNTIL 10 AM CST MONDAY FOR WIZ005-010>012- 018-019-030-035-036. && $$ SHORT TERM.....MPC LONG TERM......LUCHS AVIATION.......AK
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SUNDAY ISSUED AT 224 PM CST SAT FEB 21 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW THE NEXT ARCTIC COLD FRONT DROPPING SOUTHEAST ACROSS NORTH-CENTRAL TO WEST-CENTRAL WISCONSIN EARLY THIS AFTERNOON. LIGHT AREA OF SNOW RESIDING WITHIN A WEAK MID-LEVEL FGEN ZONE IS MOVING EAST ACROSS CENTRAL WISCONSIN...THOUGH SUSPECT SOME OF THAT AREA IS NOT REACHING THE GROUND. ADDITIONALLY...ALSO SEEING LIGHT RETURNS DEVELOPING OVER OCONTO AND MARINETTE COUNTIES WHERE WEAK SURFACE CONVERGENCE HAS DEVELOPED. THIS WILL LIKELY EXPAND LATER THIS AFTERNOON BASED ON TRENDS AND ACCORDING TO THE HI-RES MODELS. BEHIND THE FRONT...ARCTIC HIGH PRESSURE IS BUILDING SOUTHEAST INTO THE NORTHERN PLAINS WHERE TEMPS WERE WELL BELOW ZERO EARLIER THIS MORNING. FORECAST CONCERNS INCLUDE LIGHT SNOW CHANCES THROUGH THIS EVENING...BEFORE ATTENTION TURNS TO DANGEROUS WIND CHILLS. TONIGHT...A SHORTWAVE TROUGH OVER SOUTH-CENTRAL CANADA WILL DRIVE THE COLD FRONT ACROSS THE REST OF THE REGION THIS EVENING...WHILE A BEEFY ARCTIC HIGH MOVES INTO THE NORTHERN GREAT PLAINS AND WESTERN GREAT LAKES. AHEAD OF THE SHORTWAVE...THE HIGHER RES MODELS ARE DEPICTING A WEAK SURFACE TROUGH DEVELOPING OVER NORTHEAST WISCONSIN THIS EVENING WHICH COULD PROMOTE LIGHT SNOW DEVELOPMENT. HAVE KEPT A SMALL CHANCE IN THE FORECAST THROUGH THE EVENING TO ACCOUNT FOR THIS FEATURE. OTHERWISE...THE INCOMING ARCTIC HIGH WILL PUSH RESIDUAL MID-LEVEL MOISTURE TO THE EAST WHICH WILL END SNOW CHANCES BY AROUND MIDNIGHT. TEMPERATURES SHOULD FALL QUICKLY AS SKIES CLEAR AND ARCTIC AIR POURS ACROSS THE REGION. POTENTIAL IS THERE FOR DECOUPLING OVER N-C WISCONSIN...BUT THINKING IF WINDS BECOME CALM IT WILL BE ONLY FOR A BRIEF TIME. THE COMBINATION OF COLD TEMPS AND THE BRISK NW WINDS SUPPORT THE WIND CHILL ADVISORY CURRENTLY IN EFFECT SO NO CHANGES TO HEADLINES. SUNDAY...COLD ADVECTION WILL CONTINUE INTO SUNDAY MORNING AND TEMPS COULD CONTINUE THEIR FALL INTO MID-MORNING DESPITE AMPLE SUNSHINE. THE PRESSURE GRADIENT WILL SLACKEN A BIT THROUGH THE DAY AS THE CENTER OF THE HIGH DRIFTS CLOSER TO THE REGION...BUT PROJECTED WIND CHILLS WILL ONLY WARM TO AROUND 15 TO 22 BELOW THROUGH THE AFTERNOON. THIS IS CLOSE ENOUGH TO LEAVE THE ENDING TIME OF THE ADVISORY ALONE. HIGHS WILL ONLY WARM INTO THE -5 TO 0 RANGE NORTH TO THE 5 TO 10 ABOVE RANGE SOUTH. .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY ISSUED AT 224 PM CST SAT FEB 21 2015 A LOOK AT THE RECENT BEHAVIOR OF THE 500 MB PATTERN FITS IN WELL WITH OUR TEMPERATURES THIS MONTH. A WESTERN RIDGE AND EASTERN TROUGH ARE QUITE PERSISTENT...SHOWING CHANGES MORE IN AMPLITUDE THAN POSITION. WITH THAT...OUR TEMPERATURES HAVE SPENT TIME VARYING BETWEEN BELOW NORMAL AND WAY BELOW NORMAL. FOR THE TIME BEING...THIS TREND LOOKS TO CONTINUE. SUNDAY NIGHT INTO MONDAY MORNING SHOWS TEMPERATURES BOTTOMING OUT NEARLY AS LOW AS THEY HAVE GOTTEN THIS WINTER. FORECASTING WIND CHILLS WILL BE DIFFICULT ACROSS THE NORTH. CALM WINDS WILL HELP TEMPERATURES FALL TO THEIR COLDEST POSSIBLE LEVELS...BUT CALM CONDITIONS COULD PRECLUDE A WARNING BY NOT MEETING THE WIND THRESHOLD. MORE WIND WILL HELP PUSH WIND CHILLS DOWN...BUT WOULD BE LIMITING BY ARRESTING TEMPERATURE FALLS. GIVEN THE UNCERTAINTY...WILL LET LATER SHIFTS MAKE THE FINAL DECISION ON ANYTHING TO BE ISSUED FOR WIND CHILL. AN ADVISORY FOR MOST OR ALL OF THE AREA IS PLAUSIBLE...AND A WARNING IN NORTH CENTRAL WISCONSIN MAY BE ON THE TABLE. THOUGH THERE MIGHT BE A LACK OF CONFIDENCE IN THE PRECISE HEADLINES...CONFIDENCE IS QUITE HIGH THAT IT WILL BE VERY COLD AND THOSE GOING TO WORK AND SCHOOL MONDAY MORNING SHOULD PREPARE ACCORDINGLY. INCREASING SOUTHWEST WINDS ON MONDAY CAN BE EXPECTED...ESPECIALLY LATE IN THE AFTERNOON AND EVENING HOURS. THESE WINDS WILL HELP BOOST TEMPERATURES LATE MONDAY INTO TUESDAY. WITH ANOTHER IN THE PARADE OF LOWS SLIDING BY TO OUR NORTHEAST BRINGING AN ARCTIC FRONT TO OUR AREA...WE WILL HAVE ANOTHER CHANCE FOR SNOW SHOWERS. GUIDANCE REMAINS FRUSTRATINGLY ON THE EDGE BETWEEN BRINGING SOME LIGHT SNOW WELL INTO THE AREA...OR ONLY BRINGING A GLANCING BLOW TO THE NORTH AND EAST. ULTIMATELY THIS FORECAST DOES NOT MAKE SIGNIFICANT CHANGES...THE EQUIVALENT OF DUMPING THE PUCK INTO THE CORNER AND HOPING THAT A LINE CHANGE OF MODELS WILL BRING MORE CLARITY. BITTER COLD RETURNS FOR WEDNESDAY AND THURSDAY BUT WITH SOME HOPE FOR A SLIGHT BUMP UP TO MERELY BELOW NORMAL TEMPERATURES LATE IN THE WEEK. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1136 AM CST SAT FEB 21 2015 AN AREA OF LIGHT SNOW AND FLURRIES IS EXPECTED TO MOVE OVER THE CENTRAL WISCONSIN AND FOX VALLEY TAF SITES THIS AFTERNOON. INCLUDED MVFR VSBYS AT AUW AND CWA BUT NOT FURTHER EAST TO GET A BETTER HANDLE ON TIMING/CONDITIONS. ANY LIGHT SNOW WILL EXIT THE REGION DURING THE EVENING...AND AN INCOMING ARCTIC AIRMASS WILL PROMOTE CLEARING SKIES FOR THE REST OF THE NIGHT. VFR CONDITIONS WILL THEN CONTINUE THROUGH THE END OF THE TAF PERIOD. NOTICE TO AIRPORT GROUNDS CREW AND MAINTENANCE...THERE COULD BE A SIGNIFICANT PERIOD OF BLOWING AND DRIFTING SNOW MONDAY EVENING THROUGH TUESDAY MORNING. SOUTHWEST WINDS WILL INCREASE TO 15 TO 25 KNOTS WITH GUSTS TO 35 KNOTS POSSIBLE. THIS COULD PRODUCE SIGNIFICANT BLOWING AND DRIFTING SNOW. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR WIZ005- 010>012-018-019-030-035-036. && $$ SHORT TERM.....MPC LONG TERM......LUCHS AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1136 AM CST SAT FEB 21 2015 UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE .SHORT TERM...TODAY...TONIGHT...AND SUNDAY ISSUED AT 408 AM CST SAT FEB 21 2015 SLOW MOVING ARCTIC FRONT WILL MOVE ACROSS THE AREA THIS MORNING THEN STALL JUST TO OUR SOUTH AS A WAVE MOVES NORTHEAST ALONG THE FRONT. THE NAM AND RUC SUGGEST THAT THERE WILL BE SOME LOW LEVEL CONVERGENCE OVER THE FOX VALLEY AND HAVE FIVE TO TEN HUNDREDTHS OF AN INCH OF WATER EQUIVALENT. THESE MODELS USUALLY PRETTY GOOD WITH SMALL SCALE FEATURES SO WENT ALONG WITH THIS IDEA FOR THE MOST PART. SNOW SHOWERS OR FLURRIES LIKELY ELSEWHERE THIS AFTERNOON. THIS WILL BE ONE OF THE WARMEST DAYS IN A WEEK OR SO WITH HIGHS IN THE 20S. WHATEVER SNOW IS LEFTOVER THIS EVENING SHOULD END BY MIDNIGHT AS THE FRONT ACCELERATES TO THE SOUTH AND ARCTIC AIR POURS INTO WISCONSIN. LOWS TONIGHT SHOULD GET BELOW ZERO OVER ALL BUT EAST CENTRAL WISCONSIN. WINDS SHOULD BE SUFFICIENT TO PRODUCE WIND CHILLS OF 20 TO 30 BELOW ZERO IN CENTRAL AND NORTHCENTRAL WISCONSIN WHERE ADVISORIES HAVE BEEN ISSUED. TEMPERATURES SHOULD BE AROUND 15 DEGREES BELOW NORMAL. SUNDAY SHOULD BE BLUSTERY AND COLD WITH HIGHS IN THE SINGLE NUMBERS. SOME PLACES IN THE NORTH COULD STAY JUST BELOW ZERO. WINDS CHILLS WILL BE 10 TO 20 BELOW ZERO OR COLDER. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY ISSUED AT 408 AM CST SAT FEB 21 2015 WESTERN 500MB RIDGE WILL KEEP REINVENTING ITSELF THROUGH 240 HOURS... LEADING TO BELOW NORMAL TEMPERATURES ACROSS OUR NECK OF THE WOODS. THE GOOD NEWS IS THE CALENDAR WILL TURN TO MARCH BY THE END OF THE FORECAST PERIOD...THUS YOU WOULD THINK TEMPERATURES WOULD FINALLY RETURN A LITTLE BIT CLOSER TO NORMAL. LAST CHECK OF THE CLIMATE DATA AT GREEN BAY...WAUSAU AND RHINELANDER INDICATED TEMPERATURES WERE RUNNING 8 TO 11 DEGREES BELOW NORMAL FOR THE MONTH. VERY IMPRESSIVE AND POSSIBLY COULD NOT GET ANY WORSE! THE ROLLER COASTER RIDE WILL BE BOTTOMING OUT SUNDAY NIGHT INTO MONDAY MORNING. WIND CHILL READINGS HARD TO GAUGE ACROSS THE NORTH DUE TO THE RIDGE SOUTH OF OUR AREA. SHOULD BE A LIGHT WIND AROUND... BUT OUR TYPICAL COLD SPOTS LIKE MERRILL...TOMAHAWK AND LAND O LAKES WILL PROBABLY GO CALM FOR AWHILE AND WOULD NOT MEET THE TRUE WIND REQUIREMENTS FOR A WIND CHILL ADVISORY OR WARNING. WILL LET LATER SHIFTS DECIDE IF WIND CHILL WARNING OR ADVISORY WOULD BE NEEDED FOR THIS AREA...WHILE THE REST OF NORTHEAST AND EAST-CENTRAL WISCONSIN WILL NEED A WIND CHILL ADVISORY. INCREASING SOUTHWEST WINDS ON MONDAY CAN BE EXPECTED...ESPECIALLY LATE IN THE AFTERNOON AND EVENING HOURS. WITH SUCH A FLUFFY SNOW FROM YESTERDAY...COULD BE SOME BLOWING AND DRIFTING OF THE SNOW. ENJOY THE HEAT ON TUESDAY AS NEXT CLIPPER SYSTEM DROPS INTO THE AREA. WILL HAVE CHANCES FOR SNOW SHOWERS WITH THIS FEATURE AND ALONG THE ARCTIC FRONT. NEW ECMWF MORE BULLISH ON TEMPERATURES WITH TEMPERATURES POSSIBLE REACH THE LOWER TO MIDDLE 30S. DID NOT STRAY TOO FAR FROM PREVIOUS FORECAST FOR NOW SINCE THERE HAS BEEN SOME DIFFERENCES IN HOW MUCH WARM AIR WILL MAKE IT INTO THE AREA AHEAD OF THE ARCTIC FRONT. BITTER COLD RETURNS FOR WEDNESDAY AND THURSDAY WITH SOME MODIFICATION IN TEMPERATURES NEXT FRIDAY. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1136 AM CST SAT FEB 21 2015 AN AREA OF LIGHT SNOW AND FLURRIES IS EXPECTED TO MOVE OVER THE CENTRAL WISCONSIN AND FOX VALLEY TAF SITES THIS AFTERNOON. INCLUDED MVFR VSBYS AT AUW AND CWA BUT NOT FURTHER EAST TO GET A BETTER HANDLE ON TIMING/CONDITIONS. ANY LIGHT SNOW WILL EXIT THE REGION DURING THE EVENING...AND AN INCOMING ARCTIC AIRMASS WILL PROMOTE CLEARING SKIES FOR THE REST OF THE NIGHT. VFR CONDITIONS WILL THEN CONTINUE THROUGH THE END OF THE TAF PERIOD. NOTICE TO AIRPORT GROUNDS CREW AND MAINTENANCE...THERE COULD BE A SIGNIFICANT PERIOD OF BLOWING AND DRIFTING SNOW MONDAY EVENING THROUGH TUESDAY MORNING. SOUTHWEST WINDS WILL INCREASE TO 15 TO 25 KNOTS WITH GUSTS TO 35 KNOTS POSSIBLE. THIS COULD PRODUCE SIGNIFICANT BLOWING AND DRIFTING SNOW. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR WIZ005- 010>012-018-019-030-035-036. && $$ SHORT TERM.....RDM LONG TERM......ECKBERG AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
543 AM CST SAT FEB 21 2015 UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE .SHORT TERM...TODAY...TONIGHT...AND SUNDAY ISSUED AT 408 AM CST SAT FEB 21 2015 SLOW MOVING ARCTIC FRONT WILL MOVE ACROSS THE AREA THIS MORNING THEN STALL JUST TO OUR SOUTH AS A WAVE MOVES NORTHEAST ALONG THE FRONT. THE NAM AND RUC SUGGEST THAT THERE WILL BE SOME LOW LEVEL CONVERGENCE OVER THE FOX VALLEY AND HAVE FIVE TO TEN HUNDREDTHS OF AN INCH OF WATER EQUIVALENT. THESE MODELS USUALLY PRETTY GOOD WITH SMALL SCALE FEATURES SO WENT ALONG WITH THIS IDEA FOR THE MOST PART. SNOW SHOWERS OR FLURRIES LIKELY ELSEWHERE THIS AFTERNOON. THIS WILL BE ONE OF THE WARMEST DAYS IN A WEEK OR SO WITH HIGHS IN THE 20S. WHATEVER SNOW IS LEFTOVER THIS EVENING SHOULD END BY MIDNIGHT AS THE FRONT ACCELERATES TO THE SOUTH AND ARCTIC AIR POURS INTO WISCONSIN. LOWS TONIGHT SHOULD GET BELOW ZERO OVER ALL BUT EAST CENTRAL WISCONSIN. WINDS SHOULD BE SUFFICIENT TO PRODUCE WIND CHILLS OF 20 TO 30 BELOW ZERO IN CENTRAL AND NORTHCENTRAL WISCONSIN WHERE ADVISORIES HAVE BEEN ISSUED. TEMPERATURES SHOULD BE AROUND 15 DEGREES BELOW NORMAL. SUNDAY SHOULD BE BLUSTERY AND COLD WITH HIGHS IN THE SINGLE NUMBERS. SOME PLACES IN THE NORTH COULD STAY JUST BELOW ZERO. WINDS CHILLS WILL BE 10 TO 20 BELOW ZERO OR COLDER. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY ISSUED AT 408 AM CST SAT FEB 21 2015 WESTERN 500MB RIDGE WILL KEEP REINVENTING ITSELF THROUGH 240 HOURS... LEADING TO BELOW NORMAL TEMPERATURES ACROSS OUR NECK OF THE WOODS. THE GOOD NEWS IS THE CALENDAR WILL TURN TO MARCH BY THE END OF THE FORECAST PERIOD...THUS YOU WOULD THINK TEMPERATURES WOULD FINALLY RETURN A LITTLE BIT CLOSER TO NORMAL. LAST CHECK OF THE CLIMATE DATA AT GREEN BAY...WAUSAU AND RHINELANDER INDICATED TEMPERATURES WERE RUNNING 8 TO 11 DEGREES BELOW NORMAL FOR THE MONTH. VERY IMPRESSIVE AND POSSIBLY COULD NOT GET ANY WORSE! THE ROLLER COASTER RIDE WILL BE BOTTOMING OUT SUNDAY NIGHT INTO MONDAY MORNING. WIND CHILL READINGS HARD TO GAUGE ACROSS THE NORTH DUE TO THE RIDGE SOUTH OF OUR AREA. SHOULD BE A LIGHT WIND AROUND... BUT OUR TYPICAL COLD SPOTS LIKE MERRILL...TOMAHAWK AND LAND O LAKES WILL PROBABLY GO CALM FOR AWHILE AND WOULD NOT MEET THE TRUE WIND REQUIREMENTS FOR A WIND CHILL ADVISORY OR WARNING. WILL LET LATER SHIFTS DECIDE IF WIND CHILL WARNING OR ADVISORY WOULD BE NEEDED FOR THIS AREA...WHILE THE REST OF NORTHEAST AND EAST-CENTRAL WISCONSIN WILL NEED A WIND CHILL ADVISORY. INCREASING SOUTHWEST WINDS ON MONDAY CAN BE EXPECTED...ESPECIALLY LATE IN THE AFTERNOON AND EVENING HOURS. WITH SUCH A FLUFFY SNOW FROM YESTERDAY...COULD BE SOME BLOWING AND DRIFTING OF THE SNOW. ENJOY THE HEAT ON TUESDAY AS NEXT CLIPPER SYSTEM DROPS INTO THE AREA. WILL HAVE CHANCES FOR SNOW SHOWERS WITH THIS FEATURE AND ALONG THE ARCTIC FRONT. NEW ECMWF MORE BULLISH ON TEMPERATURES WITH TEMPERATURES POSSIBLE REACH THE LOWER TO MIDDLE 30S. DID NOT STRAY TOO FAR FROM PREVIOUS FORECAST FOR NOW SINCE THERE HAS BEEN SOME DIFFERENCES IN HOW MUCH WARM AIR WILL MAKE IT INTO THE AREA AHEAD OF THE ARCTIC FRONT. BITTER COLD RETURNS FOR WEDNESDAY AND THURSDAY WITH SOME MODIFICATION IN TEMPERATURES NEXT FRIDAY. && .AVIATION...FOR 12Z TAF ISSUANCE ISSUED AT 543 AM CST SAT FEB 21 2015 CEILINGS WILL GENERALLY RANGE FROM 2500 TO 3500 FEET TODAY WITH SCATTERED SNOW SHOWERS AND FLURRIES. THERE IS A CHANCE THAT AN AREA OF SNOW WITH A FEW HOURS OF IFR CONDITIONS COULD FORM OVER EASTERN WISCONSIN DURING THE AFTERNOON OR EARLY EVENING BUT THAT IS NOT A SURE THING. SKIES SHOULD BECOME MOSTLY CLEAR OVERNIGHT WITH THE EXCEPTION OF SOME LAKE EFFECT CLOUDS NORTH OF RHINELANDER. NOTICE TO AIRPORT GROUNDS CREW AND MAINTENANCE...THERE COULD BE A SIGNIFICANT PERIOD OF BLOWING AND DRIFTING SNOW MONDAY EVENING THROUGH TUESDAY MORNING. SOUTHWEST WINDS WILL INCREASE TO 15 TO 25 KNOTS WITH GUSTS TO 35 KNOTS POSSIBLE. THIS COULD PRODUCE SIGNIFICANT BLOWING AND DRIFTING SNOW. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR WIZ005- 010>012-018-019-030-035-036. && $$ SHORT TERM.....RDM LONG TERM......ECKBERG AVIATION.......RDM
FORECAST DISCUSSION FOR ROUTINE MORNING FORECAST ISSUANCE

.SHORT TERM...TODAY...TONIGHT...AND SUNDAY ISSUED AT 408 AM CST SAT FEB 21 2015 SLOW MOVING ARCTIC FRONT WILL MOVE ACROSS THE AREA THIS MORNING THEN STALL JUST TO OUR SOUTH AS A WAVE MOVES NORTHEAST ALONG THE FRONT. THE NAM AND RUC SUGGEST THAT THERE WILL BE SOME LOW LEVEL CONVERGENCE OVER THE FOX VALLEY AND HAVE FIVE TO TEN HUNDREDTHS OF AN INCH OF WATER EQUIVALENT. THESE MODELS USUALLY PRETTY GOOD WITH SMALL SCALE FEATURES SO WENT ALONG WITH THIS IDEA FOR THE MOST PART. SNOW SHOWERS OR FLURRIES LIKELY ELSEWHERE THIS AFTERNOON. THIS WILL BE ONE OF THE WARMEST DAYS IN A WEEK OR SO WITH HIGHS IN THE 20S. WHATEVER SNOW IS LEFTOVER THIS EVENING SHOULD END BY MIDNIGHT AS THE FRONT ACCELERATES TO THE SOUTH AND ARCTIC AIR POURS INTO WISCONSIN. LOWS TONIGHT SHOULD GET BELOW ZERO OVER ALL BUT EAST CENTRAL WISCONSIN. WINDS SHOULD BE SUFFICIENT TO PRODUCE WIND CHILLS OF 20 TO 30 BELOW ZERO IN CENTRAL AND NORTHCENTRAL WISCONSIN WHERE ADVISORIES HAVE BEEN ISSUED. TEMPERATURES SHOULD BE AROUND 15 DEGREES BELOW NORMAL. SUNDAY SHOULD BE BLUSTERY AND COLD WITH HIGHS IN THE SINGLE NUMBERS. SOME PLACES IN THE NORTH COULD STAY JUST BELOW ZERO. WINDS CHILLS WILL BE 10 TO 20 BELOW ZERO OR COLDER. .LONG TERM...SUNDAY NIGHT THROUGH FRIDAY ISSUED AT 408 AM CST SAT FEB 21 2015 WESTERN 500MB RIDGE WILL KEEP REINVENTING ITSELF THROUGH 240 HOURS... LEADING TO BELOW NORMAL TEMPERATURES ACROSS OUR NECK OF THE WOODS. THE GOOD NEWS IS THE CALENDAR WILL TURN TO MARCH BY THE END OF THE FORECAST PERIOD...THUS YOU WOULD THINK TEMPERATURES WOULD FINALLY RETURN A LITTLE BIT CLOSER TO NORMAL. LAST CHECK OF THE CLIMATE DATA AT GREEN BAY...WAUSAU AND RHINELANDER INDICATED TEMPERATURES WERE RUNNING 8 TO 11 DEGREES BELOW NORMAL FOR THE MONTH. VERY IMPRESSIVE AND POSSIBLY COULD NOT GET ANY WORSE! THE ROLLER COASTER RIDE WILL BE BOTTOMING OUT SUNDAY NIGHT INTO MONDAY MORNING. WIND CHILL READINGS HARD TO GAUGE ACROSS THE NORTH DUE TO THE RIDGE SOUTH OF OUR AREA. SHOULD BE A LIGHT WIND AROUND... BUT OUR TYPICAL COLD SPOTS LIKE MERRILL...TOMAHAWK AND LAND O LAKES WILL PROBABLY GO CALM FOR AWHILE AND WOULD NOT MEET THE TRUE WIND REQUIREMENTS FOR A WIND CHILL ADVISORY OR WARNING. WILL LET LATER SHIFTS DECIDE IF WIND CHILL WARNING OR ADVISORY WOULD BE NEEDED FOR THIS AREA...WHILE THE REST OF NORTHEAST AND EAST-CENTRAL WISCONSIN WILL NEED A WIND CHILL ADVISORY. INCREASING SOUTHWEST WINDS ON MONDAY CAN BE EXPECTED...ESPECIALLY LATE IN THE AFTERNOON AND EVENING HOURS. WITH SUCH A FLUFFY SNOW FROM YESTERDAY...COULD BE SOME BLOWING AND DRIFTING OF THE SNOW. ENJOY THE HEAT ON TUESDAY AS NEXT CLIPPER SYSTEM DROPS INTO THE AREA. WILL HAVE CHANCES FOR SNOW SHOWERS WITH THIS FEATURE AND ALONG THE ARCTIC FRONT. NEW ECMWF MORE BULLISH ON TEMPERATURES WITH TEMPERATURES POSSIBLE REACH THE LOWER TO MIDDLE 30S. DID NOT STRAY TOO FAR FROM PREVIOUS FORECAST FOR NOW SINCE THERE HAS BEEN SOME DIFFERENCES IN HOW MUCH WARM AIR WILL MAKE IT INTO THE AREA AHEAD OF THE ARCTIC FRONT. BITTER COLD RETURNS FOR WEDNESDAY AND THURSDAY WITH SOME MODIFICATION IN TEMPERATURES NEXT FRIDAY. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1052 PM CST FRI FEB 20 2015 CIGS TO MAINLY BE MVFR FOR THE REST OF TNGT THRU SAT MORNING AS A CDFNT MOVES ACROSS WI. THERE WL STILL BE SOME LIGHT SNOW OR FLURRIES ACROSS NE WI OVRNGT/SAT MORNING UNTIL THE FNT EXITS THE AREA WITH VSBYS DROPPING DOWN TO 4 OR 5SM. A WIND SHIFT TO THE NW SAT MORNING WL PREVAIL FOR THE REST OF SAT WITH CIGS GRADUALLY IMPROVING TO LOW-END VFR CONDITIONS IN THE AFTERNOON. CANNOT RULE OUT SOME FLURRIES REDEVELOPING IN THE AFTERNOON DUE TO STEEP LOW- LEVEL LAPSE RATES. ONCE WE GET PAST SUNSET...DRIER AIR WL ARRIVE AS HI PRES BEGINS TO BUILD SE FROM CANADA. SKIES ARE EXPECTED TO GRADUALLY CLEAR SAT NGT WITH VFR CONDITIONS ANTICIPATED. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY FROM 3 AM TO 11 AM CST SUNDAY FOR WIZ005- 010>012-018-019-030-035-036. && $$ SHORT TERM.....RDM LONG TERM......ECKBERG AVIATION.......AK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1043 PM MST SUN FEB 22 2015 .UPDATE... ISSUED AT 800 PM MST SUN FEB 22 2015 STEADY ACCUMULATING SNOW IS NOT LIKELY ACROSS THE FAR E PLAINS AND PER COORD WITH SURROUNDING WFO/S...I REMOVED THE HILITES FOR THAT REGION. /HODANISH && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 251 PM MST SUN FEB 22 2015 ...HEAVY SNOW OVER THE MOUNTAINS CONTINUES... ...SNOW WINDING DOWN TONIGHT FOR THE LOWER ELEVATIONS... IN GENERAL...FORECAST IS WORKING OUT FAIRLY WELL ACROSS THE CWA. FORECAST AMOUNTS FOR THE NORTHERN AND EASTERN ZONES WERE TOO HIGH...AND TOO LOW FOR THE MTS AND SRN ZONES...BUT OVERALL AMOUNTS ARE NOT TOO SURPRISING. AS THE UPPER TROUGH SHEARS OFF TO THE WEST OVER CA...AND MID LEVEL WINDS CONTINUE TO VEER TO THE SW AND W...WILL SEE SNOWFALL GRADUALLY DIMINISH OVER THE ERN PLAINS E OF I- 25 TONIGHT...SO HAVE REDUCED POPS THROUGH TONIGHT IN THAT AREA. WILL LEAVE A SNOW ADVISORY GOING WITH ADDITIONAL LIGHT ACCUMS OF AN INCH OR TWO POSSIBLE...AND CONTINUED ICY ROAD CONDITIONS. HIGH RES MODELS ARE SHOWING THE HEAVIER SNOW GRADUALLY BEING TIED TO THE ERN MTS AND HIGHER TRRN...AND THIS LOOKS REASONABLE. THERE COULD BE SOME BANDED PRECIP SPILLING OVER TO PORTIONS OF THE I-25 CORRIDOR...ESPECIALLY W OF I-25...THROUGH THIS EVENING...SO WILL LEAVE THE WARNING INTACT FOR THE I-25 ZONES. IN FACT...THE HRRR CONTINUES TO SHOW SN PICKING UP FOR A BIT EARLY THIS EVENING OVER EL PASO COUNTY BEFORE DIMINISHING AFTER MIDNIGHT. LATER SHIFT CAN REEVALUATE AND DOWNGRADE THE WARNING IF IT LOOKS LIKE THIS WILL NOT MATERIALIZE. OVER THE MTS...SNOW CONTINUES THROUGH TOMORROW. WIND SENSOR IS OUT AT KCPW...BUT AS MENTIONED IN THE EARLIER UPDATE BLIZZARD CONDITIONS WERE OCCURRING THERE AND WILL LIKELY CONTINUE THROUGH PERIODS OF MONDAY BEFORE THINGS BEGIN TO QUIET DOWN. LATEST GUIDANCE SUGGESTS AN ADDITIONAL 2-3 FEET OVER THE SAN JUANS BY TUESDAY...SO WOULD NOT BE SURPRISED TO SEE A FEW SPOTS NEAR 4 FEET BY THE TIME THIS ENDS...AND WITH HIGH WINDS SOME SERIOUS DRIFTING AS WELL...INCREASING AN UNSTABLE SNOW LOAD ON THE SLOPES AND RESULTING IN EXTREME AVALANCHE THREAT OVER THE HIGH COUNTRY FOR THE NEXT FEW DAYS. INTERESTINGLY...LATEST GUIDANCE IS SHOWING H7 TEMPS OF MINUS 21 DEGREES OVER OUR AREA TONIGHT...SIGNIFICANTLY COLDER THAN WHAT THE MODELS WERE SHOWING JUST A COUPLE OF DAYS AGO...AND IN LINE WITH THE ECMWF GUIDANCE FROM A WEEK AGO! THE MUCH COLDER AIR HAS CUT BACK A BIT ON DENDRITIC SNOW GROWTH...AND LIMITED SNOW AMOUNTS TO SOME EXTENT FOR OUR ERN ZONES. AS A RESULT OF THE COLDER AIR ALOFT...EXPECT SOME LOWS CLOSE TO ZERO TONIGHT EVEN WITH THE CLOUD COVER...AND HAVE REDUCED HIGHS A BIT FOR TOMORROW WITH TEMPS PROBABLY STAYING IN THE TEENS FOR THE MOST PART. EXPECT GRADUAL IMPROVEMENT TOMORROW FOR THE PLAINS...AS WRLY FLOW INCREASES. MODELS ARE SHOWING A LACK OF QPF THERE TOMORROW...BUT WITH ABUNDANT LOW LEVEL MOISTURE AND CONTINUED SHALLOW UPSLOPE...AM RELUCTANT TO REMOVE POPS COMPLETELY...SO WILL LEAVE LOW POPS IN PLACE OVER THE PLAINS. OVER THE MTS...HEAVY SNOW CONTINUES AT TIMES WITH BLIZZARD CONDITIONS FOR THE ERN SAN JUANS. SAN LUIS VALLEY WILL BE BETWEEN THE TWO REGIMES AND COULD SEE SOME SHSN...BUT NOTHING PARTICULARLY HEAVY EXPECTED. WELCOME BACK TO WINTER! ROSE .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 251 PM MST SUN FEB 22 2015 MONDAY NIGHT THE UPR LOW IS FORECAST TO MOVE EASTWARD FROM SRN NV...WITH THE GFS SHOWING THE LOW CENTER OVR NERN AZ BY 12Z TUE AND THE NAM BEING A LITTLE FARTHER WEST. EITHER WAY...SNOW CONTINUES OVR THE SWRN CO MTNS. HOWEVER WITH THE GFS BEING FARTHER EAST THAN THE NAM...PCPN IS ALSO FORECAST TO BE OVR THE SAN LUIS VALLEY AND THE ERN MTNS...WHILE THE NAM HAS DRY CONDITIONS EVERY BUT THE SW MTNS. ON TUE THE UPR LOW IS EXPECTED TO CONTINUE AN EASTWARD TRACK...MOVING ACRS NRN NM...BRINGING MAINLY SOME PCPN CHANCES TO MAINLY THE FAR SOUTHERN PORTIONS OF THE FORECAST AREA. HIGH TEMPS ON TUE WL BE A LITTLE WARMER...BUT STILL BELOW AVERAGE...ESPECIALLY WITH THE SNOW COVER. TUE NIGHT AND EARLY WED DRY CONDITIONS ARE EXPECTED OVR THE AREA AS THE UPR LOW MOVES INTO NORTHERN TX. A NEW UPR TROF DROPS INTO THE STATE FROM THE SOUTH BY LATE WED MORNING...PUSHING MORE COLD AIR INTO THE AREA. IN THE LATE MORNING OR EARLY AFTERNOON HOURS...PCPN IS EXPECTED TO SPREAD SOUTH ACRS THE AREA AS WELL...WITH PROBABLY THE HARDEST HIT AREAS BEING THE EASTERN MTS AND IMMEDIATELY ADJACENT PLAINS AND THE PALMER DIVIDE. THE GFS AND ECMWF ARE IN PRETTY GOOD AGREEMENT...KEEPING PCPN ACRS MUCH OF THE SERN PLAINS AND MTNS THRU THU NIGHT AND MUCH OF FRI AS ANOTHER UPR DISTURBANCE MOVES INTO THE AREA FROM THE PACIFIC NW. THIS WL BRING THE POTENTIAL FOR SEVERAL INCHES OF SNOW OVR THE MTNS. UPSLOPE FLOW OVR ERN AREAS WL HELP TO BRING SEVERAL INCHES TO THE THE WET MTNS...SOUTHERN SANGRES AND THE ADJACENT PLAINS...WITH MAYBE A COUPLE TO A FEW INCHES ALONG THE I-25 CORRIDOR...AND LIGHTER ACCUMULATIONS OVR THE FAR SERN PLAINS. UNSETTLE WEATHER IS FORECAST TO CONTINUE NEXT WEEKEND AS ANOTHER UPR TROF AFFECTS THE STATE...KEEPING THE WEATHER COOL AND BRINGING PCPN CHANCES TO MUCH OF THE AREA AND THE POTENTIAL FOR SEVERAL INCHES OF SNOW IN THE MTNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1042 PM MST SUN FEB 22 2015 MVFR AND IFR CONDITIONS TO CONTINUE AT COS AND PUB WITH LIGHT SNOW AND FLURRIES ENDING AFT 12Z. LIGHT UPSLOPE FLOW AND ABUNDANT MOISTURE OVER THE PAST FEW DAYS LOOKS TO KEEP MVFR CIGS IN PLACE THROUGH THE AFTERNOON...WITH CLEARING SKIES AND VFR CONDITIONS DEVELOPING THROUGH THE LATE AFTERNOON AND EARLY EVENING WITH EXPECTED WEAK DOWNSLOPE FLOW. MVFR AND IFR CONDITIONS WITH OCCASIONAL LIGHT SNOW AND FLURRIES EXPECTED TO CONTINUE AT ALS THROUGH THE EARLY MORNING HOURS. MVFR CIGS POSSIBLE THROUGH THE LATE MORNING WITH VFR CONDITIONS EXPECTED TO DEVELOP THROUGH THE AFTERNOON. && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 5 AM MST MONDAY FOR COZ058>063- 072>088. WINTER WEATHER ADVISORY UNTIL 5 PM MST MONDAY FOR COZ069>071. WINTER STORM WARNING UNTIL 5 PM MST MONDAY FOR COZ064>067. BLIZZARD WARNING UNTIL 11 PM MST MONDAY FOR COZ068. && $$ UPDATE...HODANISH SHORT TERM...28/ROSE LONG TERM...28 AVIATION...MW
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
350 AM EST MON FEB 23 2015 .DISCUSSION... TODAY/TONIGHT...COLD FRONT CURRENTLY JUST NORTH OF FL WILL WEAKEN AS IT SHIFTS SWEETHEART AND EVENTUALLY INTO THE AREA TONIGHT. ANY FOG/STRATUS INITIALLY OVER THE REGION WILL BURN OFF BY LATE MORN WITH PARTLY CLOUDY SKIES EXPECTED THROUGH MUCH OF THE DAY. TEMPS WILL REMAIN ABOVE NORMAL WITH HIGHS RANGING FROM THE UPPER 70S OVER LAKE AND VOLUSIA COUNTY TO LOW 80S FARTHER SOUTH. MODELS SHOW A LITTLE HIGHER MOISTURE WORKING INTO NRN AREAS LATER IN THE AFT AHEAD OF THE FRONT WHICH MAY LEAD TO A FEW SHRAS...SO HAVE INCLUDED SLIGHT CHANCE POPS NORTH OF ORLANDO. THE LATEST HRRR INDICATES SOME ISO SHRA ACTIVITY EVEN FARTHER SOUTH BY LATE DAY BUT LOW LEVEL MOISTURE IS FAIRLY SHALLOW AND MOS POPS REMAIN BELOW MENTIONABLE LEVELS SO WILL KEEP RAIN CHANCES OUT OF THE FORECAST ELSEWHERE. AS FRONT MOVES INTO CENTRAL FLORIDA TONIGHT RAIN CHANCES WILL CONTINUE TO INCREASE SLIGHTLY MAINLY OVER NORTHERN PORTIONS OF THE AREA. ALSO CLOUD COVER WILL INCREASE AS LOW CLOUD DECK BUILDS IN BEHIND THE BOUNDARY. SINCE FRONT WILL BE WEAK...OVERNIGHT TEMPS WILL STAY ABOVE NORMAL WITH LOWS IN THE UPPER 50S TO LOW 60S. TUE...WEAK COLD FRONT SHOULD SHIFT TO THE SOUTHERN SECTIONS. FORECAST SOUNDINGS SHOW A SHALLOW COOL AIR MASS WITH CONSIDERABLE LOW CLOUDINESS ESPECIALLY ACROSS THE NORTH HALF. ISENTROPIC LIFT WILL BE SHALLOW/WEAK SO EXPECT ONLY SCATTERED LIGHT PRECIP. MAX TEMPS WILL BE KNOCKED DOWN CONSIDERABLY ACROSS THE NORTH WITH THE CLOUD COVER AND NORTHERLY WIND FLOW. SOUTHERN SECTIONS WILL HAVE A LITTLE MORE CLOUDINESS DEVELOPING IN THE AFTERNOON BUT MAX TEMPS SHOULD STILL BE 80 AROUND OKEECHOBEE. TUE NIGHT...A WEAK LOW EAST OF THE COASTAL WATERS IS FORECAST TO PULL AWAY TO THE NORTHEAST BUT THE WEAK/SHALLOW FRONTAL BOUNDARY SHOULD CONTINUE TO EXTEND ACROSS THE SOUTHERN PENINSULA. MOS POPS ARE 20-30 PERCENT...BUT THE MAIN CONCERN MAY ACTUALLY TURN OUT TO BE LOW STRATUS/FOG. WILL NOT MENTION YET AND KEEP POPS AT 20 PERCENT OR LESS. WED-THU...THE 00Z GFS/ECMWF HAVE COME INTO GOOD AGREEMENT DURING THIS PERIOD. THE MAIN FEATURE WILL BE A SOUTHERN STREAM SHORTWAVE TROUGH THAT MOVES ACROSS THE DEEP SOUTH WED WHILE GRADUALLY DAMPENING OUT. THE ACCOMPANYING SURFACE LOW IS FORECAST TO PUSH INTO NORTH FLORIDA WED AFTERNOON AND SHIFT TO OFFSHORE THE CAROLINAS BY 12Z THU. THE WARM SECTOR WILL ENCOMPASS THE LOCAL AREA AS LOW LEVEL WINDS BECOME SOUTHERLY AND INCREASE WED INTO WED NIGHT. THE MODELS SHOW MAIN PRECIP OCCURRING NEAR A WARM FRONT TO OUR NORTH ON WED THEN AS COLD FRONT DROPS TOWARDS THE AREA OVERNIGHT...A BAND OF CONVECTION WILL ACCOMPANY IT. THE BAND OF CONVECTION SHOULD SHIFT INTO SOUTHERN SECTIONS ON THU. HAVE NOT MADE MUCH CHANGE TO THE PREVIOUS FORECAST WHICH HAS CHANCE POPS NORTH AND SLIGHT CHANCE IN THE SOUTH WED AND WED NIGHT...EXCEPT BECOMING LIKELY IN THE NORTH WED NIGHT. CHANCE POPS SHOULD BE A LITTLE HIGHER IN THE SOUTH ON THU. WITH QUITE STRONG LOW LEVEL WINDS AS SURFACE LOW MOVES BY JUST TO OUR NORTH...THE MENTION OF ISOLATED STORMS LOOKS GOOD WED NIGHT ESPECIALLY NORTH HALF...WITH A SLIGHT CHANCE THAT STORMS COULD BE STRONG. FRI-NEXT MON...LARGE HIGH PRESSURE CENTERED OVER THE MID PART OF THE COUNTRY SHOULD PUSH FRONTAL BOUNDARY INTO THE NORTHERN BAHAMAS ON FRI BUT THE MODELS SHOW FRONT HANGING UP AND THE ASSOCIATED MOISTURE FROM IT LIFTING BACK NORTH. THIS WILL ALLOW A MENTION OF SLIGHT CHANCE TO CHANCE POPS THROUGH THE WEEKEND. TEMPERATURES GENERALLY EXPECTED TO STAY NEAR TO JUST BELOW SEASONAL NORMS FRI THEN MODERATE SAT AS BREEZY ONSHORE FLOW DEVELOPS...THEN BE ABOVE NORMAL BY SUN AS BREEZY ONSHORE CONTINUES. A DEEP LAYER HIGH PRESSURE RIDGE IS INDICATED OVER THE AREA NEXT MON...SO A WARM AND DRY DAY LOOKS TO BE ON TAP. && .AVIATION...PATCHY/AREAS OF FOG THROUGH EARLY MORNING WILL PRODUCE TEMPO IFR/MVFR CONDS THROUGH 13-14Z. ANY FOG SHOULD THEN BURN OFF WITH VFR CONDS EXPECTED INTO THE AFT. WEAK FRONT MOVING INTO THE REGION TONIGHT WILL USHER IN A LOWER CLOUD DECK WITH IFR/LIFR CIGS BUILDING SOUTHWARD OVER THE REGION AS PER LATEST MOS GUIDANCE. SOME PATCHY FOG MAY ALSO BE POSSIBLE BUT AT THIS TIME NOT EXPECTING WIDESPREAD LOWER VISIBILITIES. RAIN CHANCES WILL INCREASE SLIGHTLY INTO LATE DAY AND TONIGHT WITH THE FRONT BUT POPS ARE LOW ENOUGH TO KEEP MENTION OUT OF THE TAFS FOR NOW. && .MARINE... TODAY/TONIGHT...LIGHT TO GENTLE BREEZE EXPECTED TODAY OVER THE WATERS WITH WINDS INITIALLY OUT OF THE W/SW BECOMING MORE NORTHERLY AND INCREASING INTO TONIGHT AS A WEAK FRONT MOVES THROUGH THE REGION. NORTHERLY SURGE DOES NOT APPEAR AS STRONG AS IT HAD IN PREVIOUS MODEL RUNS WITH WIND SPEEDS GENERALLY AROUND 15 KNOTS. SEAS BUILDING TO 6 FEET OVER THE OFFSHORE WATERS NORTH OF THE CAPE BY LATE TONIGHT STILL LOOKS REASONABLE...SO WILL MAINTAIN THESE WAVE HEIGHTS IN THE FORECAST. TUE-FRI...A VERY PROGRESSIVE WEATHER PATTERN WILL LEAD TO QUICKLY CHANGING WIND FIELDS THROUGH THE PERIOD. A WEAK LOW IS FORECAST JUST EAST OF THE WATERS TUE WHICH SHOULD PRODUCE A BRIEF PERIOD OF NORTHERLY WINDS 15-20 KNOTS. THEN ON WED...THE WINDS SHOULD START OFF LIGHT AND BECOME SOUTHERLY WHILE INCREASING...AS A SURFACE LOW MOVES TOWARDS NORTH FLORIDA. THE LOW WILL LIFT QUICKLY NORTHEAST AND SWING A COLD FRONT INTO THE WATERS THU. IN ADDITION TO INCREASED RAIN CHANCES WED NIGHT AND THU...BREEZY SOUTHERLY FLOW WILL BECOME NORTHERLY BEHIND THE FRONT THU NIGHT AND CONTINUE INTO FRI. && .PRELIMINARY POINT TEMPS/POPS... DAB 78 59 64 52 / 20 30 40 20 MCO 82 61 73 57 / 10 20 30 20 MLB 80 61 72 58 / 10 20 20 30 VRB 81 60 77 58 / 10 10 20 20 LEE 79 59 67 55 / 10 20 40 20 SFB 80 60 68 55 / 20 20 40 20 ORL 81 60 71 57 / 10 20 30 20 FPR 82 60 78 58 / 10 10 20 20 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM...WEITLICH LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
419 AM EST MON FEB 23 2015 .SYNOPSIS... A COLD FRONT WILL PUSH ACROSS THE REGION TODAY AND BECOME STATIONARY SOUTH OF THE AREA TONIGHT. DEVELOPING LOW PRESSURE WILL TRACK ALONG THE STATIONARY FRONT OVER THE ATLANTIC TUESDAY. HIGH PRESSURE WILL BRIEFLY BUILD IN TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED BY STRONGER LOW PRESSURE FROM THE GULF OF MEXICO THAT PASSES OFFSHORE WEDNESDAY NIGHT. STRONG HIGH PRESSURE CENTERED NORTH OF THE AREA WILL EXPAND TO BECOME THE PRIMARY FEATURE LATE WEEK INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... TODAY...SHORTWAVE ENERGY EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT IS HELPING PROVIDE SOME UPPER SUPPORT FOR LOW LEVEL FORCING ALONG A COLD FRONT THAT STRETCHES FROM EASTERN NORTH CAROLINA BACK TO THE LOWER MISSISSIPPI VALLEY. THE RESULT IS A LARGE BAND OF WIDESPREAD RAINFALL THAT IS IMPACTING MUCH OF THE NORTHERN HALF OF THE FORECAST AREA THIS MORNING. POPS THROUGH THE REMAINDER OF THE MORNING FEATURE 100 POPS TO THE NORTH...RANGING TO SLIGHT CHANCES FAR TO THE SOUTH AROUND MCINTOSH COUNTY. THE BEST FORCING WILL REMAIN FOCUSED TO THE NORTH AND THAT IS WHERE THE HEAVIEST RAIN WILL FALL. THEN FOLLOWING THE RECENT RUNS OF THE HRRR AND THE RAP...THE BULK OF THE PRECIPITATION WILL COME TO AN END FROM WEST TO EAST IN THE LATE MORNING TO EARLY AFTERNOON HOURS. TEMPERATURES ARE CURRENTLY QUITE MILD ACROSS THE REGION...MAINLY IN THE UPPER 50S AND LOW 60S. THESE VALUES WILL REMAIN STEADY THROUGH DAYBREAK...AND ONLY BEGIN TO FALL WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT. BASED ON THE TIMING IN THE HRRR AND RAP...THE WIND SHIFT AND ASSOCIATED INFILTRATION OF COOLER AIR WILL BEGIN TAKING PLACE AROUND 13Z OR SO. HIGH TEMPERATURES FOR THE DAY WILL OCCUR JUST BEFORE THE FRONT BEGINS ITS SOUTHWARD MARCH...WITH MID 50S IN MOST AREAS AND EVEN SOME UPPER 50S AND LOW 60S POSSIBLE FOR SOUTHEAST GEORGIA. TEMPERATURES WILL THEN STEADILY FALL THROUGH THE DAY. TONIGHT...THE COLD FRONT WILL BECOME NEARLY STATIONARY TO THE SOUTH AND SOUTHEAST OF THE REGION AS HIGH PRESSURE BEGINS TO BRIDGE ACROSS THE OHIO VALLEY AND INTO THE MID ATLANTIC. BY LATE TONIGHT...THE HIGH WILL SETTLE INTO COLD AIR DAMMING POSITION WITH INCREASINGLY COOL AIR OOZING IN FROM THE NORTHEAST. EARLY IN THE TONIGHT PERIOD...THE MODELS GENERALLY SHOW A PRECIPITATION LULL PERIOD AS THE FORCING ALONG THE FRONT IS DISPLACED TO THE SOUTH AND SOUTHEAST AND THE UPPER SUPPORT WANES. HOWEVER...BY VERY LATE TONIGHT THE NOSE OF A 80-90 KT 500 MB JET PUSHES IN FROM THE EAST COINCIDENT WITH AN AREA OF SHALLOW LOW LEVEL ISENTROPIC LIFT. SOME OF THE MODELS SHOW PRECIPITATION BREAKING OUT CLOSER TO SUNRISE AT THE SAME TIME AS SUB FREEZING AIR FILTERS IN FROM THE NORTHEAST. SOUNDINGS SHOW THAT WHATEVER PRECIPITATION DOES FALL WILL LIKELY FALL AS FREEZING RAIN/DRIZZLE AND THROUGH THE VERY LATE TONIGHT PERIOD WILL MAINLY IMPACT THE EXTREME NORTH...ALONG AND NEAR THE SANTEE RIVER. THE BULK OF THIS EVENT WILL THEN OCCUR INTO TUESDAY MORNING. BY LATE TONIGHT...LOWS WILL REACH THE LOW 30S FOR MUCH OF SOUTHEAST SOUTH CAROLINA WITH MID TO UPPER 30S IN SOUTHEAST GEORGIA. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... TUESDAY...THE STALLED OUT FRONT AND ITS ASSOCIATED BAROCLINIC ZONE WILL BE FOUND NOT FAR OFF THE SE COAST. CHANNELED VORTICITY ARRIVING IN THE FAST MOVING AND BROADLY CYCLONIC FLOW ALOFT WILL TRIGGER CYCLOGENESIS A COUPLE HUNDRED MILES OFF THE NE FLORIDA COAST. AT THE SAME TIME...UPPER DIVERGENCE/DIFLUENCE ASSOCIATED WITH THE EXIT REGION OF A ROBUST 130 KT JET AND ISENTROPIC ASCENT ON MAINLY THE 280K AND 285K SURFACES /AROUND 1500-2500 FT/ WILL COMBINE WITH PRODUCE AN EXPANDING AREA OF RAIN ACROSS THE FORECAST AREA. THERE STILL REMAINS SOME DISPARITIES BETWEEN THE VARIOUS MODEL GUIDANCE...BUT WE HAVE LEANED TOWARD A SOLUTION MOST SIMILAR TO A BLEND OF THE NAM...ECMWF AND CANADIAN MODELS AS OPPOSED TO THE GFS. COLDER AIR WILL BE FILTERING INTO THE REGION AS A TRANSIENT HIGH PRESSURE WEDGE DEVELOPS BEHIND THE COLD FRONT STALLED OFFSHORE. THIS WILL CAUSE A CONCERN FOR THE POTENTIAL FOR FREEZING RAIN AND DRIZZLE OVER SEVERAL PARTS OF THE FORECAST AREA. SOUNDING DATA REVEALS THAT THE BEST CHANCE FOR FREEZING SURFACE TEMPS AND/OR WET BULBS WILL OCCUR MAINLY INLAND FROM US-17 IN SC AND OVER JENKINS AND SCREVEN COUNTIES IN SE GA. THIS INCLUDES PARTS OF THE CHARLESTON AND BEAUFORT METRO AREAS...AND IT IS IN THESE LOCATIONS WHERE WE HAVE GONE AHEAD WITH A FREEZING RAIN ADVISORY FROM 4 AM UNTIL 2 PM TUESDAY. WHILE IT IS CERTAINLY COLD ENOUGH FOR ICE/SNOW ALOFT...THERE IS A PRONOUNCED WARM NOSE AROUND 900-750 MB WHICH WILL TURN WILL ALLOW FOR MELTING OF THE FROZEN PRECIP. BUT THERE IS ENOUGH MOISTURE AND COLDER AIR BELOW TO ALLOW FOR THE LIQUID DROPS TO REFREEZE. THERE CAN CERTAINLY BE SOME SLEET MIXED IN...BUT THE BULK OF THE PRECIP LOOKS TO BE FREEZING RAIN AND/OR DRIZZLE. OUR CONFIDENCE ON THE AMOUNT OF ICING IS MODERATE AT BEST...SINCE WE HAVE HAD A SHORT DURATION WARM SPELL AND MUCH OF THE PRECIP MAY TURN OUT BE RATHER LIGHT IN INTENSITY. THAT SAID...WE DO ANTICIPATE A FEW HUNDREDTHS OF AN INCH OF FREEZING RAIN ON VARIOUS SURFACES. KEEP IN MIND THAT THE TALLER BRIDGES OF THE AREA CAN FREEZE BEFORE ROAD SURFACES. THE DON HOLT BRIDGE IN THE CHARLESTON AREA PROBABLY HAS THE BEST CHANCE OF EXPERIENCING ANY ICING PROBLEMS TUESDAY MORNING...BUT WE CAN/T ENTIRELY DISCOUNT THE RAVENEL AND WANDO BRIDGES ALSO GETTING SOME ICE ON THEM. DEPENDING UPON THE INTENSITY OF THE PRECIP WE MAY NEED TO EXPAND THE ADVISORY A LITTLE FURTHER SOUTH INTO GEORGIA AT A LATER TIME. TEMPS LOOK TO BE ABOVE FREEZING IN THE EARLY TO MID AFTERNOON...THUS ANY FREEZING PRECIP WILL CHANGE OVER TO LIQUID BEFORE TAPERING OFF LATE. FOR NOW WE BELIEVE THAT THE PRECIP OVER MUCH OF SE GA...ESPECIALLY TO THE SOUTH OF I-16 WILL BE ALL OR MAINLY LIQUID WITH QPF/S OF 1/10 TO 1/4 INCH TO OCCUR. TEMPS WON/T GO MUCH OF ANYWHERE...EVEN DROPPING A COUPLE OF DEGREES DUE TO THE PRECIP...AND WE/LL BE MAINLY IN THE LOWER AND MIDDLE 30S NORTH/NW TO THE LOWER 40S SOUTH. TUESDAY NIGHT...THE SURFACE WAVE OVER THE ATLANTIC AND THE ASSOCIATED FORCING PULL AWAY AS A MESO-HIGH BUILDS FROM THE WEST. THIS WILL TEMPORARILY SHUT OFF THE PRECIP...AND WE WILL NEED TO WATCH FOR POSSIBLE RE-FREEZING OF THE EARLIER RAINS...ESPECIALLY OVER THE CHARLESTON QUAD-COUNTY DISTRICT. WEDNESDAY AND WEDNESDAY NIGHT...A POTENT SHORT WAVE IN THE DESERT SW TODAY WILL SHIFT THROUGH THE SOUTHERN PLAINS WEDNESDAY AND HEADS INTO THE SE AT NIGHT. THIS TRIGGERS SURFACE CYCLOGENESIS IN THE NORTHERN GULF OF MEXICO BEFORE THE LOW TRACKS JUST OFF THE LOCAL COASTS BY LATE IN THE PERIOD. LARGE SCALE FORCING FROM THESE FEATURES AND A POWERFUL WEST-EAST 150 KT UPPER JET WILL ALLOW FOR CONSIDERABLE OVER-RUNNING RAINS TO DEVELOP BY WEDNESDAY AFTERNOON...BEFORE TAPERING OFF FROM WEST/SW TO EAST/NE LATE WEDNESDAY NIGHT. THIS PROMISES TO BE A PRETTY GOOD SOAKER...WITH PWATS OF 1-1.5 INCHES TO PREVAIL. SOME PLACES COULD EASILY ACHIEVE THESE AMOUNTS GIVEN THAT WE ARE CARRYING CATEGORICAL POPS. RIGHT NOW IT LOOKS TO BE ALL LIQUID UNLESS THE OVER-RUNNING RAINS ARRIVE EARLIER THAN EXPECTED. TEMPS WILL REMAIN FAR BELOW NORMAL. THURSDAY...MUCH DRIER AIR OVERSPREADS THE REGION BEHIND THE EXITING SHORT AVE AND SURFACE LOW...LEADING TO A DRY BUT CHILLY DAY WITH TEMPS AGAIN FAR BELOW SEASONAL NORMS. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A HUMONGOUS AND ROBUST 1040 MB CANADIAN HIGH BUILDING OUT OF THE GREAT PLAINS WILL EXPAND EAST AND SOUTH AND COVERS MUCH OF THE NATION EAST OF THE ROCKIES...INCLUDING THE LOCAL AREA. THIS LEADS TO DRY AND CHILLY CONDITIONS INTO FRIDAY...BEFORE THE HIGH SHIFTS INTO THE ATLANTIC OVER THE WEEKEND AND EARLY NEXT WEEK AND TEMPS BEGIN TO MODERATE. A COASTAL TROUGH WILL LIKELY FORM DURING THIS TRANSITION JUST OFF OUR COAST...AND WE LOOK FOR AT LEAST A SMALL CHANCE OF SHOWERS IN RESPONSE. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... ONGOING VFR CONDITIONS AT KCHS AND KSAV WILL ONLY LAST A FEW MORE HOURS AS RAINFALL AND LOWERING CEILINGS BEGIN TO IMPACT THE TERMINALS. AT KCHS...RAINFALL WILL BECOME STEADY AND PERIODICALLY MODERATE IN INTENSITY. CEILINGS ARE EXPECTED TO FALL TO MVFR BY 08Z...THOUGH VISIBILITIES IN RAIN COULD BE MVFR OR TEMPORARILY IFR AT TIMES. CEILINGS WILL CONTINUE TO STEADILY FALL AND REACH IFR LEVELS AROUND 10Z. THE PRECIPITATION WILL COME TO AN END AROUND 16Z AND THEN LITTLE TO NO RAIN IS EXPECTED THROUGH THE END OF THE FORECAST. IFR CEILINGS WILL STICK THROUGH THE DAY...LIFTING TO MVFR IN THE LATE EVENING HOURS. THE MAIN WIND SHIFT WITH THE FRONT WILL TAKE PLACE AROUND NOON AND WINDS THEREAFTER WILL INCREASE AND BECOME NORTHERLY. AT KSAV...RAINFALL CHANCES ARE MUCH LOWER AND THE OVERALL TIMING OF LOWERING CEILINGS WILL BE ABOUT 2-3 HOURS LATER THAN KCHS. SIMILARLY...IFR CEILINGS WILL SETTLE IN BY LATE MORNING AND REMAIN THROUGH THE DAY. THE WIND SHIFT WITH THE FRONT WILL ARRIVE AT KSAV IN THE EARLY AFTERNOON. AN IMPROVEMENT TO MVFR SHOULD TAKE PLACE CLOSER TO MIDNIGHT. EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS OF VARYING CATEGORIES WILL CONTINUE MUCH OF THE TIME MONDAY NIGHT INTO THURSDAY...ALTHOUGH INTERLUDES OF VFR ARE POSSIBLE BETWEEN RAIN EVENTS. ALSO OF NOTE...THERE IS A SLIGHT CHANCE FOR FREEZING/FROZEN PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY MORNING. && .MARINE... TODAY AND TONIGHT...A COLD FRONT WILL SINK SOUTHWARD ACROSS THE REGION AND IS EXPECTED TO PUSH ACROSS THE WATERS MAINLY IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...A SIGNIFICANT NORTH TO NORTHEAST SURGE IS EXPECTED TO BEGIN WITH RAPIDLY INCREASING WINDS AND SEAS. WINDS WILL INCREASE FIRST ACROSS THE CHARLESTON COUNTY WATERS AND THE CHARLESTON HARBOR IN THE EARLY AFTERNOON...REACHING THE GEORGIA WATERS IN THE LATE AFTERNOON AND EARLY EVENING HOURS. THE NEARSHORE WATERS WILL SEE WINDS INCREASE INTO THE 20 TO 25 KT RANGE...INCLUDING THE CHARLESTON HARBOR...WITH GUSTS TO 30 KT POSSIBLE FOR THE OUTER GEORGIA WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL WATERS THROUGH THE OVERNIGHT. THE NORTH TO NORTHEAST SURGE WILL CONTINUE TONIGHT IN THE WAKE OF THE FRONT AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE WATERS. WINDS WILL LIKELY REACH THEIR PEAK IN THE MID TO LATE EVENING HOURS WITH GUSTS TO 30 KT POSSIBLE ACROSS ALL WATERS. SEAS WILL CONTINUE TO INCREASE REACHING 4-6 FT WITHIN 20 NM AND 6-9 FT OUT TO 60 NM. TUESDAY...ONGOING SMALL CRAFT ADVISORIES WILL CONTINUE INTO THE AFTERNOON IN ASSOCIATION WITH THE GRADIENT BETWEEN THE ATLANTIC LOW AND A WEAK INLAND HIGH PRESSURE WEDGE. WHILE WE CAN/T RULE OUT A LITTLE FREEZING RAIN IN CHARLESTON HARBOR...THE BULK OF THE WET WEATHER LOOKS TO BE IN THE FORM OF LIQUID. TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS WILL IMPROVE AS THE ATLANTIC LOW PULLS AWAY AND ANOTHER AREA OF HIGH PRESSURE ARRIVES FROM THE WEST. WINDS AND SEAS WILL BE FAR BELOW ANY ADVISORY THRESHOLDS. LATE WEDNESDAY INTO THURSDAY...CONDITIONS AGAIN WILL DETERIORATE AS INTENSIFYING LOW PRESSURE DEVELOPS IN THE GULF OF MEXICO AND TRACKS OVER OR NEAR THE LOCAL WATERS LATE WEDNESDAY NIGHT/EARLY THURSDAY...BEFORE PULLING AWAY THURSDAY AFTERNOON. SMALL CRAFT ADVISORIES ARE AGAIN LIKELY AS A RESULT. FRIDAY THROUGH SATURDAY...A STRENGTHENING REGION OF CONTINENTAL HIGH PRESSURE WILL OVERSPREAD THE REGION AND GIVEN COLD ADVECTION AND A TIGHTENING OF THE PRESSURE GRADIENT ADDITIONAL SMALL CRAFT ADVISORIES ARE ANTICIPATED. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR GAZ087-088. SC...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR SCZ040-042>045-047>050-052. MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST TUESDAY FOR AMZ352. SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST TUESDAY FOR AMZ350. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 PM EST TUESDAY FOR AMZ354. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EST TUESDAY FOR AMZ374. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 PM EST TUESDAY FOR AMZ330. && $$ NEAR TERM...BSH SHORT TERM... LONG TERM... AVIATION...BSH MARINE...BSH
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1201 AM CST MON FEB 23 2015 .UPDATE... 757 PM CST MADE A COUPLE TWEAKS TO GOING FORECAST`S TEMPERATURES...MAINLY TO RAISE LOW TEMPS A BIT TONIGHT...ESPECIALLY IN THE URBAN HEAT ISLAND AND ALSO NUDGED HIGHS UP A BIT MONDAY AS WELL. COLD ARCTIC AIR CONTINUES TO SLOWLY FILTER INTO THE AREA...BUT GRADIENT IS REMAINING TIGHT ENOUGH TO KEEP A BIT OF WIND BLOWING WHICH IS PREVENTING TEMPS FROM TANKING DESPITE THE CLEAR SKY. THE TYPICALLY COLDER AND MORE SHELTERED AREAS LIKE FOX AND ROCK RIVER VALLEYS WILL LIKELY SEE WINDS DECOUPLE A BIT MORE THAN OTHER AREAS WITH TEMPS DROPPING TO AROUND 10 BELOW THERE...BUT DOWNTOWN CHICAGO WILL PROBABLY ONLY DROP TO AROUND ZERO. THE MINOR ADJUSTMENTS TO TEMPERATURES AND WINDS SUGGEST THAT MOST AREAS WILL FALL SHORT OF REACHING WIND CHILL ADVISORY CRITERIA...WITH MOST LIKELY AREAS TO REACH IT BEING NORTH CENTRAL ILLINOIS INTO THE FAR WESTERN CHICAGO SUBURBS...WITH WIND CHILLS ELSEWHERE LIKELY "ONLY" DROPPING TO 15-20 BELOW. ITS POSSIBLE THAT MIDNIGHT SHIFT COULD KILL WIND CHILL ADVISORY EARLY...BUT JUST NOT COMFORTABLE MAKING CHANGES TO THE HEADLINE AT THIS TIME. IZZI && .SHORT TERM... 234 PM CST TONIGHT THROUGH WEDNESDAY... COLD TEMPERATURES AND DANGEROUSLY LOW WIND CHILLS TONIGHT AND EARLY MONDAY ARE THE IMMEDIATE FORECAST CONCERNS IN THE SHORT TERM. WIND CHILL ADVISORY REMAINS IN EFFECT FOR ENTIRE CWA FROM MIDNIGHT TONIGHT THROUGH 10 AM CST MONDAY MORNING. COULD EVEN APPROACH ROCKFORDS RECORD LOW OF -12 F. 1047 MB HIGH PRESSURE CENTERED OVER THE NORTHERN PLAINS THIS AFTERNOON WILL CONTINUE TO SPREAD SOUTHEAST TO THE MID-MISSISSIPPI VALLEY TONIGHT. ARCTIC AIR...VERY DRY AIR MASS AND CLEAR SKIES... AND SLOWLY DIMINISHING WINDS WILL COMBINE TO PRODUCE BITTER COLD SUB-ZERO TEMPERATURES ACROSS THE FORECAST AREA OVERNIGHT. WITH LOW TEMPS REACHING FROM -2 TO -14 ACROSS THE CWA AND WINDS JUST UNDER 10 MPH BY MORNING...WIND CHILLS RANGING FROM NEAR 20 BELOW TO NEARLY 30 BELOW ARE EXPECTED BY SUNRISE MONDAY. THUS WIND CHILL ADVISORY REMAINS IN EFFECT FOR ALL COUNTIES WITH NO CHANGES. ON MONDAY...THE SURFACE HIGH AND EASTERN PORTION OF THE RIDGE AXIS WILL CONTINUE TO PUSH SOUTHEAST ACROSS THE AREA IN THE MORNING BEFORE BECOMING ELONGATED ACROSS THE OHIO VALLEY LATE IN THE DAY. COLD MORNING MINS AND SHALLOW MIXING IN THE VICINITY OF THE RIDGE WILL LIKELY KEEP DAYTIME TEMPS IN THE SINGLE DIGITS TO NEAR 10 DEGREES IN MOST AREAS...DESPITE WINDS BECOMING WEST-SOUTHWEST AND STARTING TO INCREASE DURING THE AFTERNOON. THIS WILL LIKELY RESULT IN A RECORD LOW-MAX TEMP FOR THE ROCKFORD AREA MONDAY...AS THE CURRENT RECORD LOW-MAX FOR RFD 2/23 IS A FAIRLY MILD 17 DEGREES. WIND CHILLS WILL REMAIN SUB-ZERO THROUGH THE DAY...DESPITE MOSTLY SUNNY SKIES. ATTENTION THEN TURNS TO ANOTHER STRONG SHORT WAVE TROUGH DIGGING FROM MANITOBA INTO ONTARIO AND ACROSS THE NORTHERN LAKES INTO TUESDAY...WHICH RESULTS IN DEEP SURFACE LOW PRESSURE PASSING NORTHEAST OF THE GREAT LAKES MONDAY NIGHT AND TUESDAY AND TIGHTENING OF THE SURFACE PRESSURE GRADIENT ACROSS THE MIDWEST. WEST-SOUTHWEST WINDS WILL BECOME BLUSTERY MONDAY NIGHT SUPPORTING STEADY OR SLOWLY RISING TEMPERATURES MONDAY NIGHT ESPECIALLY ACROSS THE NORTH WHERE WINDS WILL BE STRONGEST. TEMPERATURES WILL RISE INTO THE 25-30 DEGREE RANGE DURING THE DAY TUESDAY BEFORE THE COLD FRONT TRAILING THE CANADIAN LOW MOVES THROUGH LATE IN THE DAY...THOUGH THE GUSTY SOUTHWEST WINDS TO 35 MPH AT TIMES WILL MAINTAIN A RAW FEEL TO THE DAY WITH WIND CHILLS IN THE TEENS AT BEST (ABOVE ZERO AT LEAST). CLOUDS WILL INCREASE TUESDAY MORNING AHEAD OF THE APPROACHING FRONT WITH SCATTERED SNOW SHOWERS OR FLURRIES AT TIMES DURING THE DAY. THE COLD FRONT MOVES THROUGH BY EARLY TUESDAY EVENING...WITH BLUSTERY NORTHWEST WINDS BRINGING COLDER AIR BACK INTO THE REGION AT LEAST IN A GLANCING NATURE INTO WEDNESDAY WITH SINGLE DIGIT TEMPS TUESDAY NIGHT AND HIGHS IN THE TEENS AND WIND CHILLS IN THE POSITIVE SINGLE DIGITS WEDNESDAY. A WEAK CLIPPER SYSTEM IS CURRENTLY PROGGED TO MOVE JUST WEST OF THE AREA LATE WEDNESDAY AND WEDNESDAY NIGHT...WHICH MAY BRING SOME LIGHT SNOW TO WESTERN PARTS OF THE CWA. LOW LEVEL WINDS ALSO LOOK TO VEER MORE NORTH-NORTHEAST WHICH MAY BRING SOME LIGHT SNOW SHOWERS INTO NORTHWEST INDIANA AND EVEN PARTS OF NORTHEAST ILLINOIS. NOT TOO EXCITED ABOUT ACCUMULATIONS WITH LAKE EFFECT AT THIS TIME...AS INVERSION HEIGHTS REMAIN FAIRLY LOW. RATZER && .LONG TERM... 234 PM CST THURSDAY THROUGH SUNDAY... REINFORCEMENT OF ARCTIC AIR CONTINUES THURSDAY AND THURSDAY NIGHT AS ANOTHER SHORT WAVE TROUGH DIGS SOUTHEAST AND MAINTAINS DEEP LARGE SCALE TROUGH OVER THE EASTERN CONUS. SURFACE HIGH BUILDS SOUTHEAST FROM THE NORTHERN PLAINS THURSDAY...INTO DOWNSTATE ILLINOIS BY FRIDAY MORNING. 850 HPA TEMPS DROP INTO THE -16 TO -20 C RANGE DURING THE PERIOD WITH LIGHT WINDS OF THE SURFACE RIDGE AND CLEARING SKIES AGAIN EXPECTED TO PRODUCE SUB-ZERO TEMPERATURES BY SUNRISE FRIDAY MORNING AND HIGHS ONLY IN THE TEENS FRIDAY...WHICH FOR THE END OF FEBRUARY IS A GOOD 20-25 DEGREES BELOW OUR NORMAL HIGHS WHICH WOULD BE NEAR 40 FOR THE END OF THE MONTH. LONGER RANGE MODEL SOLUTIONS DO OFFER SOME HOPE FOR A LITTLE MODERATION IN TEMPERATURES NEXT WEEKEND...WITH A TROUGH ELONGATING AND BECOMING CUT-OFF IN THE SOUTHWEST CONUS AND A BROAD UPPER RIDGE DEVELOPING ACROSS THE SOUTHEASTERN CONUS SATURDAY AND SUNDAY. THUS OUR ARCTIC HIGH EVENTUALLY MOVES OFF THE ATLANTIC COAST WITH SOUTHERLY FLOW DEVELOPING ACROSS THE LOWER AND MIDDLE MISSISSIPPI VALLEY BY SUNDAY. OF COURSE THIS HELPS TO FEED MILDER AND MORE HUMID AIR NORTHWARD...FOR A NORTHERN STREAM UPPER TROUGH AND SURFACE LOW WHICH WOULD ALSO BRING PRECIPITATION TO THE AREA SATURDAY NIGHT AND SUNDAY. AT THIS DISTANCE HAVE MAINTAINED A CONSERVATIVE APPROACH WITH TEMPS INTO THE MID-30S SUNDAY AND POTENTIAL FOR SOME SNOW... THOUGH IF THESE MODEL TRENDS PERSIST IT COULD BE MILDER WITH MIXED PRECIP OR RAIN ESPECIALLY ACROSS OUR SOUTHEAST. RATZER && .CLIMATE... RECORD COLD TEMPERATURES ARE POSSIBLE IN ROCKFORD ON MONDAY FEBRUARY 23RD. RECORD LOW FOR 2/23: -12 IN 1910. RECORD LOW MAX FOR 2/23: 17 IN 1934. RC && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LOW-LEVEL WIND SHEAR LATE MONDAY NIGHT. //DISCUSSION...UPDATED 06Z... HIGH PRESSURE ACROSS THE MISSOURI RIVER VALLEY EARLY THIS MORNING WILL MOVE OVER THE AREA MONDAY MORNING AND THEN INCH EAST OF THE AREA MONDAY NIGHT. WITH THAT WINDS WILL TURN FROM NORTHWEST TO WEST IN THE MORNING TO SOUTHWEST BY AFTERNOON. WINDS SPEEDS WILL INCREASE MONDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS. A STRONG LOW-LEVEL JET WILL DEVELOP ALOFT LATER MONDAY NIGHT AND SHOULD SET THE STAGE FOR LOW-LEVEL WIND SHEAR WITHIN THE 900-1500FT LAYER AS SPEEDS RAPIDLY INCREASE WITH AN INVERSION. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH IN ALL ELEMENTS. //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY...STRONG/GUSTY SW WINDS. MVFR CIGS POSSIBLE LATE. WEDNESDAY THROUGH SATURDAY...PRIMARILY VFR. MTF/IZZI && .MARINE... 332 PM CST HIGH PRESSURE MOVING ACROSS THE NORTHERN PLAINS AND UPPER MIDWEST THIS AFTERNOON INTO THE EVENING IS ALLOWING FOR NORTHERLY WINDS OF 15 TO 25 KT TO CONTINUE THIS AFTERNOON...WITH THESE SPEEDS TO LIKELY CONTINUE FOR MUCH OF TONIGHT. THIS HIGH WILL DRIFT SOUTHEAST THROUGH THE UPPER MIDWEST AND MID MISSISSIPPI VALLEY TONIGHT THROUGH MONDAY AND THEN REACH THE MID ATLANTIC WEST TO THE SOUTHERN PLAINS BY EARLY TUESDAY MORNING. AS THIS OCCURS...WINDS WILL TURN WEST AND THEN SOUTHWEST SLIGHTLY DIMINISHING ON MONDAY MORNING...BUT THEN INCREASE ONCE AGAIN MONDAY AFTERNOON WITH TO 30 KT WINDS LIKELY LATE IN THE AFTERNOON. WINDS WILL REALLY INCREASE MONDAY NIGHT INTO TUESDAY OUT AHEAD OF SOUTHWARD MOVING LOW PRESSURE OVER ONTARIO...WITH GALES LIKELY. HAVE ISSUED A GALE AND FREEZING SPRAY WARNING OVER THE ENTIRE LAKE MONDAY NIGHT THROUGH TUESDAY NIGHT AND HAVE NOT ISSUED A GALE WARNING FOR THE NEARSHORE AT THIS TIME. HOWEVER...THEY DO APPEAR TO BE A POSSIBILITY VERY EARLY TUESDAY MORNING AND WILL NEED TO CONTINUE MONITORING THIS PERIOD FOR POSSIBLE PREVAILING GALES...AND EVEN FOR A LONGER DURATION. DO HAVE HIGH CONFIDENCE WITH THE START TIME OF THE GALES ACROSS THE LAKE BUT HAVE LOWER CONFIDENCE WITH THE END TIME...WITH THE GALES POSSIBLY LASTING LONGER INTO TUESDAY NIGHT. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022- ILZ023-ILZ032-ILZ033-ILZ039 UNTIL 9 AM MONDAY. IN...WIND CHILL ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019 UNTIL 9 AM MONDAY. LM...GALE WARNING...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM MONDAY TO 3 AM WEDNESDAY. HEAVY FREEZING SPRAY WARNING...LMZ080-LMZ669-LMZ671-LMZ673- LMZ675-LMZ777-LMZ779-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...9 PM MONDAY TO 3 AM WEDNESDAY. GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567- LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY. HEAVY FREEZING SPRAY WARNING...LMZ261-LMZ362-LMZ364-LMZ366- LMZ563-LMZ565-LMZ567-LMZ868...6 PM MONDAY TO 3 AM WEDNESDAY. GALE WARNING...LMZ740-LMZ741-LMZ742...9 PM MONDAY TO NOON TUESDAY. GALE WARNING...LMZ743-LMZ744-LMZ745...MIDNIGHT TUESDAY TO NOON TUESDAY. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion NATIONAL WEATHER SERVICE LINCOLN IL 1136 PM CST Sun Feb 22 2015 .UPDATE... ISSUED AT 857 PM CST SUN FEB 22 2015 Strong Arctic high pressure will continue to build into the area overnight on schedule. Surface temperatures are still above zero, but wind speeds have been sufficient to drop Wind Chill values below zero across most of the forecast area. While wind speeds will die off some overnight as the high approaches and pressure gradient relaxes, sub-zero air temperatures will allow Wind Chill values to fall to advisory levels. Going forecast is in good shape. Only a few tweaks for the latest hourly trends are required. && .SHORT TERM...(Tonight) ISSUED AT 240 PM CST SUN FEB 22 2015 Another Arctic air mass settling into our area for tonight and Monday bringing bitterly cold wind chills tonight through the mid-morning hours of Monday with values in the -15 to -25 degree range. Latest upstream observations mostly in the single digits across north central through northeast Iowa with wind gusts up to 30 mph at times. Early morning lows are expected to dip to -2 in the far south to as low as -8 across the north just before dawn Monday. The center of the Arctic high is forecast by models to drift into southeast Iowa by 12z Monday with the surface ridge axis extending northeast into northern Illinois. Forecast soundings and the latest HRRR model suggests the cloud cover we have over the area this afternoon will drift east and south later this evening with mainly some cirrus for the first half of the night and then a mostly clear sky is expected after midnight most areas. Current Wind Chill Advisory will remain in place for late tonight through 9AM Monday morning. && .LONG TERM...(Monday through Sunday) ISSUED AT 240 PM CST SUN FEB 22 2015 As the center of the cold air mass drifts across the area tomorrow, look for winds to diminish during the day but temperatures will be slow to rise with afternoon highs struggling to 10 to 15. The high should be moving off to our east by afternoon and early evening with our next surface low and cold front tracking across southern Canada southwest through the Northern Plains. Early in the evening, surface winds will be light enough for our usual tank with early evening temperatures before we see a steady or slowly rising trend across the north and west, while further east with a lighter wind flow, early morning lows will dip several degrees below zero Monday night into Tuesday morning. As the deep surface low tracks north of Lake Superior on Tuesday, a gusty south to southwest wind should help the mercury climb into the mid 20s far east to the low to mid 30s far west where we should be able to mix out fairly well during the afternoon. With the better upper forcing remaining well to our north and very limited moisture, models not showing much if any precip associated with the boundary as it swings across our area late in the day, except for the GFS which continues to produce a large area of 0.01 qpf with this system. Not worth much more than a chance for flurries and will continue with that for later in the day on Tuesday. Then we will see another cold air mass build gradually southeast thru midweek. The GFS and latest ECMWF continue to show a weak shortwave racing southeast into the Plains on Wednesday along the periphery of the next batch of cold air for the remainder of the work week. The GFS keeps any precip associated with this wave to our west and south while the latest ECMWF has trended in that direction as well but does bring in some light QPF late Wednesday/Wednesday evening. Based on the latest westward shift with the ECMWF, will only have slight chances Wednesday night for light snow. Colder temperatures filter into the area again Wednesday night with early morning lows dropping into the single digits with wind chills dropping to near -10 by Thursday morning. And a real surprise here, the well below normal temperatures are expected to hold on across our area through at least the end of the work week with daytime highs in the teens and early morning lows dropping into the single digits with a few below zero readings again possible early Friday morning. Both the GFS and ECMWF indicate a significant change to the upper pattern with more of a southwesterly flow developing over the weekend which will lead to an increasing threat for precipitation. Models showing more agreement from what we saw yesterday with snow chances moving in starting on Saturday night with the threat for snow or rain on Sunday with warming temperatures. Even seeing some better agreement with the ensemble members with respect to the pattern change along with timing of the precip into our area later Saturday through Sunday. Temperatures will start to turn around on Saturday and Sunday, but still average below the normal highs of 40 to 45 across the area for late February. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) ISSUED AT 1136 PM CST SUN FEB 22 2015 VFR aviation weather Condtions are expected to prevail across the central Illinois terminals through the 06Z TAF valid time. Mid/high level CIGS will gradually diminish with time, with mostly clear skies expected by midday Monday. Northerly breezes from 10-15 kts tonight will become light/variable by Monday afternoon as high pressure builds across the area. Then, as the high begins to pull away Monday evening, winds will swing around to the southwest. && .ILX WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY until 9 AM CST Monday FOR ILZ027>031-036>038- 040>057-061>063-066>068-071>073. && $$ UPDATE...Bak SHORT TERM...Smith LONG TERM...Smith AVIATION...Bak
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1128 PM CST SUN FEB 22 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT) ISSUED AT 235 PM CST SUN FEB 22 2015 MAIN ISSUE OF CONCERN IN THE SHORT TERM IS THE WIND CHILL ADVISORY FOR LATE TONIGHT INTO MONDAY MORNING. THE LATEST SHORT TERM GUIDANCE KEEPS THE STRONGEST WINDS AND COLDEST TEMPERATURES ACROSS PORTIONS OF SOUTHEAST MISSOURI AND MOST OF SOUTHERN ILLINOIS. AFTER COLLABORATING WITH WFOS LSX AND LMK DECIDED TO EXPAND THE ADVISORY A ROW OF COUNTIES FARTHER SOUTH ACROSS ILLINOIS AND THEN FROM PERRY SOUTHWARD THROUGH SCOTT AND STODDARD IN MISSOURI. IT LOOKS A LITTLE FUNKY IN MISSOURI...BUT THAT IS DUE TO THE CORE OF STRONGER WINDS IN THAT REGION. THE WIND CHILLS CURRENTLY FORECAST OVER SOUTHWEST INDIANA AND ADJACENT PORTIONS OF WEST KENTUCKY DO NOT QUITE GET DOWN TO 10 BELOW...BUT LEFT THAT ALONE BECAUSE IT WILL BE CLOSE. ALTHOUGH WINDS ARE EXPECTED TO BE LIGHT MONDAY NIGHT...SOUTH WINDS WILL INCREASE QUICKLY TUESDAY MORNING AND WITH THE LOWS WELL INTO THE SINGLE DIGITS...MUCH OF SOUTHERN ILLINOIS AND SOUTHWEST INDIANA MAY SEE SOME NEGATIVE WIND CHILLS FOR A FEW HOURS TUESDAY MORNING. WILL GIVE THIS A MENTION IN THE HWO. KEPT A MENTION OF FLURRIES IN THE FORECAST LATE THIS AFTERNOON AND EVENING ROUGHLY ALONG AND SOUTH OF A LINE FROM VAN BUREN MISSOURI TO MURRAY KENTUCKY. THE HRRR AND WRF RUNS REALLY DRY UP ANY ECHOES AS THEY ENTER OUR AREA...AND THERE HASN`T BEEN ANY REPORTS OF SNOW REACHING THE GROUND THIS SIDE OF KJLN. WON`T BE COMPLETELY SURPRISED TO SEE A FEW FLURRIES...BUT MEASURABLE SNOWFALL IS HIGHLY UNLIKELY. TEMPERATURES HAVE REMAINED NEARLY STEADY ACROSS THE REGION TODAY. FIGURE THAT COLD ADVECTION WILL KICK IN AS WE HEAD INTO THE EVENING HOURS...BUT ENDED UP RAISING LOWS A BIT FOR TONIGHT. MOS GUIDANCE IS GIVING QUITE A RANGE FOR FIRST PERIOD LOWS. LOOKING UPSTREAM THIS AFTERNOON...IT APPEARS THAT GUIDANCE FOR HIGHS ON MONDAY IS A BIT TOO COLD. LEANED TOWARD THE LESS COLD NAM/MET NUMBERS...BUT IT WILL STILL STRUGGLE TO GET THROUGH THE TEENS IN MOST LOCATIONS. WIND CHILLS WILL REMAIN IN THE SINGLE DIGITS ABOVE ZERO THROUGH THE AFTERNOON. NOT SURE IF MID/HIGH CLOUDS WILL BE THICK ENOUGH TO HOLD TEMPERATURES UP MUCH MONDAY NIGHT OR NOT. WINDS SHOULD BE LIGHT OR CALM WITH HIGH PRESSURE OVERHEAD...SO IT WILL BE ANOTHER COLD ONE. DEFINITELY WENT TO THE COLD SIDE OF GUIDANCE MONDAY NIGHT. SOUTHWEST WINDS WILL INCREASE ACROSS THE AREA TUESDAY...SO A DECENT WARM UP IS FORECAST. UNFORTUNATELY WITH TEMPERATURES STARTING OFF SO COLD...IT WILL STRUGGLE TO GET TO THE FREEZING MARK. A DISTURBANCE WILL DIVE SOUTHEAST THROUGH THE GREAT LAKES TUESDAY NIGHT. THIS WILL BRING AN INCREASE IN CLOUDS AND A WEAK COLD FRONTAL PASSAGE THROUGH OUR REGION. LOWS TUESDAY NIGHT WILL ACTUALLY BE MILD...RELATIVELY SPEAKING. SOME LOCATIONS WILL STAY ABOVE 20 ALL NIGHT. .LONG TERM...(WEDNESDAY THROUGH SUNDAY) ISSUED AT 235 PM CST SUN FEB 22 2015 ANOTHER SURGE OF COLD HIGH PRESSURE WILL BUILD SOUTHEAST WEDNESDAY INTO WEDNESDAY NIGHT BEHIND A WEAK COLD FRONT. THE CENTER OF THE HIGH WILL MOVE SOUTHEAST THROUGH THE END OF THE WORK WEEK AND SETTLE OVER THE OHIO VALLEY BY 00Z SATURDAY. TEMPERATURES WILL AGAIN DROP OFF TO EVEN COLDER THAN SEASONAL NORMALS, WITH HIGHS THURSDAY AND FRIDAY ONLY IN THE 20S WITH LOWS IN THE SINGLE DIGITS TO MIDDLE TEENS. MODELS SHOW THE HIGH DRIFTING EASTWARD FOR THE EARLY PART OF THE WEEKEND. TEMPERATURES WILL MODERATE BACK IN THE 30S AHEAD OF OUR NEXT WEATHER SYSTEM. ECMWF AND GFS DIFFER ON TIMING AND TRACK OF A LOW PRESSURE SYSTEM, WITH ECMWF BEING THE FASTER OF THE MODELS WITH MORE SUBSTANTIAL QPF. ECMWF SHOWS WIDESPREAD PRECIPITATION ACROSS THE PAH FORECAST AREA SATURDAY NIGHT, WHILE GFS JUST SHOW MINIMAL QPF REACHING INTO OUR SOUTHERN COUNTIES LATE SATURDAY NIGHT. BY SUNDAY BOTH MODELS SHOW DECENT QPF ACROSS THE ENTIRE PAH FA. JUST WENT WITH SLIGHT CHANCE POPS FOR LIGHT SNOW SATURDAY NIGHT, INCREASING TO CHANCE POPS FOR RAIN ON SUNDAY. BOTH MODELS YESTERDAY SHOWED THIS SYSTEM AFFECTING OUR REGION FRIDAY NIGHT INTO SATURDAY, SO WE STILL ARE FAIRLY LOW CONFIDENCE ON TIMING. THE LATER TIMING DOES AT LEAST ALLOW SOME "WARMER" TO GET INTO OUR AREA AHEAD OF THE SYSTEM, THUS LEADING TO LESS WINTRY PRECIP. && .AVIATION... ISSUED AT 1128 PM CST SUN FEB 22 2015 VFR CONDITIONS TO DOMINATE WITH WEAKENING SURFACE WIND GRADIENT ACROSS THE WFO PAH TAF SITES. WIND GUSTS SHOULD DIMINISH ACROSS THE AREA BY 12Z. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR ILZ075>078-080>091. MO...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR MOZ076-086-087-110- 111. IN...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR INZ081-082-085>088. KY...WIND CHILL ADVISORY UNTIL 9 AM CST MONDAY FOR KYZ010-014-015- 018>020. && $$ SHORT TERM...DRS LONG TERM...RST AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
411 AM EST MON FEB 23 2015 .SYNOPSIS... A FRONTAL BOUNDARY STALLS ACROSS THE CAROLINA COAST TONIGHT AND MONDAY AS A WEAK AREA OF LOW PRESSURE MOVES EAST ALONG IT. AN ARCTIC COLD FRONT WILL PUSH ACROSS THE AREA MONDAY MORNING. HIGH PRESSURE RETURNS THROUGH MID WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST RADAR TRENDS SUPPORT WHAT 00Z MODELS HAVE TRENDED TOWARDS: A BAND OF PRECIP FORMING NORTH OF THE MAIN AXIS OF DEEPER MOISTURE OVER NE NC. THUS...HAVE BUMPED POPS UP TO LIKELY FOR A FEW HRS (MAINLY FROM 12-15Z) ACRS CENTRAL VA INCLUDING METRO RIC. PTYPE INITIALLY LIGHT RAIN BUT SHOULD TRANSITION QUICKLY TO MAINLY SNOW BY 12Z. THIS BAND EXPECTED TO SHIFT SE THROUGH THE LATER AM HRS...AND ALLOW RAIN TO CHANGE TO SLEET/SNOW INTO HAMPTON ROADS AND NE NC SOMETIME AROUND 15Z. LIGHT ACCUMULATIONS POSSIBLE...MAY ISSUE AN SPS BUT NO ADSY AS AMOUNTS SHOULD BE WELL BELOW CRITERIA. PREV DISC... 18Z/22 GFS AND RUC SUGGEST A LITTLE BETTER CHC FOR A PD OF LGT PCPN OVR SRN VA/NE NC LT TNGT INTO MID/LT MRNG HRS MON. HAVE ADJUSTED POPS UP ACRS SRN/SE VA AND NE NC. ADDED 30-50% CHC SN N OF THE VA/NC BORDER TO ABT FVX-LFI/SRN PORTION OF ERN SHORE...W/ PSBL ACCUM LESS THAN 1 INCH. MIXED PTYPC PSBL ACRS NE NC...PTNTLLY BECOMING SN BEFORE ENDING LT MON MRNG/EARLY AFTN. ANY PCPN WILL BE ARRIVING W/ LO LVL CAA INCRSG AS NEXT CDFNT PUSHES THROUGH THE RGN. TEMPS ONLY RISE A FEW DEGREES FROM 12Z READINGS THEN REMAIN STEADY OR SLOWLY FALL BACK INTO THE 20S IN THE AFTRN AS THE NEXT ARCTIC HIGH PRESSURE BUILDS INTO THE REGION ON GUSTY N-NW WINDS. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... MSTLY CLR TO PT CLDY SKIES MONDAY NIGHT AS RIDGE AXIS BUILDS OVER THE FA. RECORD LOWS IN JEOPARDY AS WINDS WEST OF THE BAY DECOUPLE ALLOWING FOR GOOD RADIATIONAL COOLING. WIND CHILL VALUES ALONG THE COAST ARE EXPECTED TO REMAIN ABOVE ADVISORY CRITERIA. ONLY THING THAT MIGHT PREVENT THE RECORDS FROM FALLING IS SOME MID / HIGH LEVEL CLOUDS NOTED IN TSCTNS. LOWS 5-10 EASTERN SHORE...10-15 ELSEWHERE EXCEPT M-U TEENS SERN BEACH AREAS. SEE CLI SECTION BELOW FOR TUES RECORD TMPS. PT TO MSTLY SUNNY TUESDAY. COLD AS H85 TMPS ONLY SUPPORT HIGHS IN THE U20S-M30S. MODELS SHOW WEAK AREA OF LOW PRESSURE (TROF) OFF THE SERN COAST TUESDAY NIGHT. EXPECT THE SGNFCNT MOISTURE TO STAY ALONG OR EAST OF THE CAROLINA COAST. WENT WITH A BIT MORE CLOUD COVERAGE OVER THE EAST THUS PT TO MSTLY CLDY SKIES AS AN UPPER LEVEL TROF SWINGS ACROSS THE NERN STATES. NOT AS COLD AS SW WINDS HOLD LOWS IN THE 20S. THE LOW PULLS FURTHER EAST AND OFF THE COAST WED. MILDER UNDER PT TO MSTLY SUNNY SKIES. WEST WINDS ALLOW TMPS TO WARM BACK INTO THE 40S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... THE LONG TERM WILL BRING SUBTLE CHANGES TO THE WEATHER. WHILE BELOW NORMAL TEMPERATURES WILL CONTINUE...THE COLD WILL NOT BE AS BRUTAL AS THE PAST WEEK. A SPLIT FLOW PATTERN WILL BRING A MORE ACTIVE SOUTHERN STREAM WILL BRING LOW PRESSURE SYSTEMS PASSING TO THE SOUTH OF THE AREA BUT WIDESPREAD PRECIPITATION IS NOT EXPECTED. FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT MID WEEK...A LOW PRESSURE SYSTEM MOVES OFF THE SOUTHEAST COAST WEDNESDAY NIGHT. PCPN SHOULD GENERALLY BE TO THE SOUTH OF THE AREA. GUIDANCE HAS VARIOUS CHANCES FOR PCPN SATURDAY THROUGH SUNDAY WITH RAIN OR SNOW SATURDAY AND SATURDAY NIGHT AND RAIN SUNDAY. A COLD FRONT APPROACHES FROM THE WEST LATE IN THE WEEKEND. KEPT POPS AT 30 PERCENT DURING THE WEEKEND. HIGH TEMPERATURES IN THE UPR 20S TO 30S THURSDAY AND FRIDAY WARM TO THE UPR 40S AND 50S BY SUNDAY. LOWS WILL BE MAINLY IN THE 20S...WARMING TO THE MID 30S NEAR THE SE VA/NE NC COAST SUNDAY MORNING. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... LIGHT FLOW IN BETWEEN STALLED BOUNDARY TO THE SOUTH AND HIGH PRESSURE WELL OFF TO THE NW OF THE REGION HAS ALLOWED AREAS OF DENSE FOG TO PERSIST NEAR THE COAST. EXPECT THIS TO CONTINUE THROUGH ABOUT 08-09Z...WITH VSBYS IMPROVING THEREAFTER AS NNE WINDS INCREASE. HOWEVER...WAVE OF LOW PRESSURE ALONG THAT BOUNDARY TO THE SOUTH WILL BRING SOME INCREASE IN DEEPER MOISTURE AND A CHC FOR RAIN CHANGING TO SNOW OR SNOW/SLEET MIX THROUGH THE MORNING FROM NW TO SE SO THAT AFTER 15Z ALL AREAS ARE EXPERIENCING MAINLY SNOW/SLEET. PRECIP SHOULD END AT KRIC AFTER 15 TO 16ZZ...BUT PERSIST UNTIL AT LEAST 18Z AT KORF/KPHF/KECG. CIGS/VSBYS WILL REMAIN IFR TO LOW END MVFR WITH THE PRECIP...THEN IMPROVE THROUGH THE AFTN. WINDS WILL BECOME STRONG FROM THE NNE AFTER 12Z WITH GUSTS TO 20 KT INLAND AND 25-30 KT NEAR THE COAST. WINDS DIMINISH TONIGHT. OUTLOOK...MAINLY DRY...COLD WITH VFR CONDITIONS EXPECTED TUE AND WED. ANOTHER SYSTEM PASSES BY TO THE SOUTH WED NIGHT/THU AND MAY BRING SOME SNOW TO MAINLY SE VA/NE NC SITES. && .MARINE... RAISED GALE WARNING FOR NC COASTAL WATERS...AS THERE LOOKS TO BE A PERIOD OF 6-9 HRS OF GUSTS TO AT LEAST 35 KT THIS AFTN/EARLY EVENING WHEN SFC LOW PUSHES ENE OFF THE NC COAST AND INTENSIFIES. RAISED SEAS TO 7-10 FT IN THESE AREAS AS WAVEWATCH TYPICALLY WELL UNDERDONE IN THIS NNE WIND PATTERN. STRONG SCA`S ELSEWHERE WITH 20-25 KT G30 KT. WILL LIKELY SEE A FEW GUSTS TO GALE FORCE BRIEFLY LATER TODAY FOR SRN VA CSTL WATERS AND MOUTH OF BAY BUT DURATION AND COVERAGE LOOKS TOO LOW ATTM TO RAISE GALES. SEAS WILL BLD TO 5-8 FT ACRS REMAINDER OF CSTL WATERS AND WAVES WILL BLD TO 3-5 FT IN THE CHES BAY. HI PRES BLDS ACRS THE REGION MON NGT/TUE...THEN MOVES OFFSHR TUE AFTN/TUE NGT...AHEAD OF NEXT ARCTIC FRONT. THIS FRONT WILL CROSS THE AREA ON WED...FOLLOWED BY ANOTHER SURGE OF COLD AIR FOR THU AND FRI. && .TIDES/COASTAL FLOODING... LOW WATER ADVISORIES HAVE ENDED AS THE NEGATIVE ANOMALIES HAVE DIMINISHED...BUT WATER LEVELS GENLY REMAIN BELOW ASTRONOMICAL TIDES THROUGH MIDWEEK. && .CLIMATE... NORFOLK`S LOW TEMPERATURE OF 9 DEGREES ON FEB 20 WAS THE COLDEST FOR SO LATE IN THE SEASON. THE MINUS 4 DEGREE READING AT SALISBURY ON FEB 21ST IS NOW THE ALL TIME LOW FOR THE MONTH OF FEBRUARY. THE CURRENT AVERAGE TEMPERATURES FOR THE MONTH OF FEBRUARY AT BOTH RICHMOND AND NORFOLK PLACE THEM IN THE TOP 10 COLDEST. WITH ADDITIONAL COLD TEMPERATURES EXPECTED NEXT WEEK...IT IS VERY LIKELY THAT BOTH SITES WILL HAVE AVERAGE TEMPERATURES IN THE TOP 10 COLDEST FEBRUARYS ON RECORD...PERHAPS IN THE TOP 5 COLDEST. RECORD LOW TEMPERATURES FOR TUESDAY 2/24: RIC...11 IN 1914 ORF...16 IN 1947 SBY...10 IN 1934 ECG...19 IN 1947 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ635>637. SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR ANZ630>632-634- 650-652-654. SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR ANZ633. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ638. SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR ANZ656. GALE WARNING UNTIL 10 PM EST THIS EVENING FOR ANZ658. && $$ SYNOPSIS...ALB/MPR NEAR TERM...BMD/MPR SHORT TERM...MPR LONG TERM...LSA AVIATION...LKB MARINE...LKB TIDES/COASTAL FLOODING... CLIMATE...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
205 AM EST MON FEB 23 2015 .SYNOPSIS... A FRONTAL BOUNDARY STALLS ACROSS THE CAROLINA COAST TONIGHT AND MONDAY AS A WEAK AREA OF LOW PRESSURE MOVES EAST ALONG IT. AN ARCTIC COLD FRONT WILL PUSH ACROSS THE AREA MONDAY MORNING. HIGH PRESSURE RETURNS THROUGH MID WEEK. && .NEAR TERM /THROUGH TODAY/... LOCALLY DENSE FOG HAS FORMED FM PORTIONS OF THE ERN SHORE TO CSTL SECTIONS IN SE VA (AND OVR THE ADJACENT WTRS). HAVE COVERED THE FOG W/ A SPECIAL WEATHER STATEMENT ON LAND...AND DENSE FOG ADVISORY OVR THE WTRS (UNTIL ABT 09Z/23). OTRW...VRB CLDS ACRS THE AREA WILL TEMPS CONTG A SLOW DROP THROUGH THE 30S/40S. SOME DRIER AIR WILL BE SPREADING SLOWLY INTO THE RGN FM THE NW BY LT TNGT...SO THE FOG IS XPCD TO DISSIPATE. LO TEMPS MNLY 30 TO 35F. 18Z/22 GFS AND RUC SUGGEST A LITTLE BETTER CHC FOR A PD OF LGT PCPN OVR SRN VA/NE NC LT TNGT INTO MID/LT MRNG HRS MON. HAVE ADJUSTED POPS UP ACRS SRN/SE VA AND NE NC. ADDED 30-50% CHC SN N OF THE VA/NC BORDER TO ABT FVX-LFI/SRN PORTION OF ERN SHORE...W/ PSBL ACCUM LESS THAN 1 INCH. MIXED PTYPC PSBL ACRS NE NC...PTNTLLY BECOMING SN BEFORE ENDING LT MON MRNG/EARLY AFTN. ANY PCPN WILL BE ARRIVING W/ LO LVL CAA INCRSG AS NEXT CDFNT PUSHES THROUGH THE RGN. TEMPS ONLY RISE A FEW DEGREES FROM 12Z READINGS THEN REMAIN STEADY OR SLOWLY FALL BACK INTO THE 20S IN THE AFTRN AS THE NEXT ARCTIC HIGH PRESSURE BUILDS INTO THE REGION ON GUSTY N-NW WINDS. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... MSTLY CLR TO PT CLDY SKIES MONDAY NIGHT AS RIDGE AXIS BUILDS OVER THE FA. RECORD LOWS IN JEOPARDY AS WINDS WEST OF THE BAY DECOUPLE ALLOWING FOR GOOD RADIATIONAL COOLING. WIND CHILL VALUES ALONG THE COAST ARE EXPECTED TO REMAIN ABOVE ADVISORY CRITERIA. ONLY THING THAT MIGHT PREVENT THE RECORDS FROM FALLING IS SOME MID / HIGH LEVEL CLOUDS NOTED IN TSCTNS. LOWS 5-10 EASTERN SHORE...10-15 ELSEWHERE EXCEPT M-U TEENS SERN BEACH AREAS. SEE CLI SECTION BELOW FOR TUES RECORD TMPS. PT TO MSTLY SUNNY TUESDAY. COLD AS H85 TMPS ONLY SUPPORT HIGHS IN THE U20S-M30S. MODELS SHOW WEAK AREA OF LOW PRESSURE (TROF) OFF THE SERN COAST TUESDAY NIGHT. EXPECT THE SGNFCNT MOISTURE TO STAY ALONG OR EAST OF THE CAROLINA COAST. WENT WITH A BIT MORE CLOUD COVERAGE OVER THE EAST THUS PT TO MSTLY CLDY SKIES AS AN UPPER LEVEL TROF SWINGS ACROSS THE NERN STATES. NOT AS COLD AS SW WINDS HOLD LOWS IN THE 20S. THE LOW PULLS FURTHER EAST AND OFF THE COAST WED. MILDER UNDER PT TO MSTLY SUNNY SKIES. WEST WINDS ALLOW TMPS TO WARM BACK INTO THE 40S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... THE LONG TERM WILL BRING SUBTLE CHANGES TO THE WEATHER. WHILE BELOW NORMAL TEMPERATURES WILL CONTINUE...THE COLD WILL NOT BE AS BRUTAL AS THE PAST WEEK. A SPLIT FLOW PATTERN WILL BRING A MORE ACTIVE SOUTHERN STREAM WILL BRING LOW PRESSURE SYSTEMS PASSING TO THE SOUTH OF THE AREA BUT WIDESPREAD PRECIPITATION IS NOT EXPECTED. FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT MID WEEK...A LOW PRESSURE SYSTEM MOVES OFF THE SOUTHEAST COAST WEDNESDAY NIGHT. PCPN SHOULD GENERALLY BE TO THE SOUTH OF THE AREA. GUIDANCE HAS VARIOUS CHANCES FOR PCPN SATURDAY THROUGH SUNDAY WITH RAIN OR SNOW SATURDAY AND SATURDAY NIGHT AND RAIN SUNDAY. A COLD FRONT APPROACHES FROM THE WEST LATE IN THE WEEKEND. KEPT POPS AT 30 PERCENT DURING THE WEEKEND. HIGH TEMPERATURES IN THE UPR 20S TO 30S THURSDAY AND FRIDAY WARM TO THE UPR 40S AND 50S BY SUNDAY. LOWS WILL BE MAINLY IN THE 20S...WARMING TO THE MID 30S NEAR THE SE VA/NE NC COAST SUNDAY MORNING. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... LIGHT FLOW IN BETWEEN STALLED BOUNDARY TO THE SOUTH AND HIGH PRESSURE WELL OFF TO THE NW OF THE REGION HAS ALLOWED AREAS OF DENSE FOG TO PERSIST NEAR THE COAST. EXPECT THIS TO CONTINUE THROUGH ABOUT 08-09Z...WITH VSBYS IMPROVING THEREAFTER AS NNE WINDS INCREASE. HOWEVER...WAVE OF LOW PRESSURE ALONG THAT BOUNDARY TO THE SOUTH WILL BRING SOME INCREASE IN DEEPER MOISTURE AND A CHC FOR RAIN CHANGING TO SNOW OR SNOW/SLEET MIX THROUGH THE MORNING FROM NW TO SE SO THAT AFTER 15Z ALL AREAS ARE EXPERIENCING MAINLY SNOW/SLEET. PRECIP SHOULD END AT KRIC AFTER 15 TO 16ZZ...BUT PERSIST UNTIL AT LEAST 18Z AT KORF/KPHF/KECG. CIGS/VSBYS WILL REMAIN IFR TO LOW END MVFR WITH THE PRECIP...THEN IMPROVE THROUGH THE AFTN. WINDS WILL BECOME STRONG FROM THE NNE AFTER 12Z WITH GUSTS TO 20 KT INLAND AND 25-30 KT NEAR THE COAST. WINDS DIMINISH TONIGHT. OUTLOOK...MAINLY DRY...COLD WITH VFR CONDITIONS EXPECTED TUE AND WED. ANOTHER SYSTEM PASSES BY TO THE SOUTH WED NIGHT/THU AND MAY BRING SOME SNOW TO MAINLY SE VA/NE NC SITES. && .MARINE... HAVE DECIDED TO ISSUE A SCA FOR THE ENTIRE WTRS STARTING LATE TNGT AND LASTING THRU MON EVENG/MON NGT. THERE IS STILL POTENTIAL FOR GALE GUSTS DURING LATE MON MORNG/AFTN TIMEFRAME AT THE MOUTH OF THE BAY AND CSTL WTRS S OF CAPE CHARLES...DUE TO STRONGER PRESSURE GRADIENT IN THIS AREA. BUT...FOR NOW WENT WITH A STRONG SCA IN THESE ZNS...AND WILL LET MIDNGT SHIFT DECIDE WHETHER TO UPGRADE TO A GALE WARNG BASED ON NEWER GUIDANCE. BASED ON 12Z/22 GUIDANCE...COLD ADVECTION REMAINS DELAYED BEHIND FRONT...WHICH WAS PUSHING OFF THE CST LATE THIS AFTN. THIS MEANS NORTHERLY WIND SURGE WON`T BEGIN UNTIL LATE TNGT/EARLY MON MORNG. SURGE WILL CONTINUE THRU MON...BEFORE WINDS DIMINISH MON NGT. SEAS WILL BLD TO 5-9 FT AND WAVES WILL BLD TO 3-5 FT IN THE CHES BAY. HI PRES BLDS ACRS THE REGION MON NGT/TUE...THEN MOVES OFFSHR TUE AFTN/TUE NGT...AHEAD OF NEXT ARCTIC FRONT. THIS FRONT WILL CROSS THE AREA ON WED...FOLLOWED BY ANOTHER SURGE OF COLD AIR FOR THU AND FRI. && .TIDES/COASTAL FLOODING... LOW WATER ADVISORIES HAVE ENDED AS THE NEGATIVE ANOMALIES HAVE DIMINISHED...BUT WATER LEVELS GENLY REMAIN BELOW ASTRONOMICAL TIDES THROUGH MIDWEEK. && .CLIMATE... NORFOLK`S LOW TEMPERATURE OF 9 DEGREES ON FEB 20 WAS THE COLDEST FOR SO LATE IN THE SEASON. THE MINUS 4 DEGREE READING AT SALISBURY ON FEB 21ST IS NOW THE ALL TIME LOW FOR THE MONTH OF FEBRUARY. THE CURRENT AVERAGE TEMPERATURES FOR THE MONTH OF FEBRUARY AT BOTH RICHMOND AND NORFOLK PLACE THEM IN THE TOP 10 COLDEST. WITH ADDITIONAL COLD TEMPERATURES EXPECTED NEXT WEEK...IT IS VERY LIKELY THAT BOTH SITES WILL HAVE AVERAGE TEMPERATURES IN THE TOP 10 COLDEST FEBRUARYS ON RECORD...PERHAPS IN THE TOP 5 COLDEST. RECORD LOW TEMPERATURES FOR TUESDAY 2/24: RIC...11 IN 1914 ORF...16 IN 1947 SBY...10 IN 1934 ECG...19 IN 1947 && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ635>638. DENSE FOG ADVISORY UNTIL 4 AM EST EARLY THIS MORNING FOR ANZ631-632-634-638-650-652-654-656. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ630>634- 650-652-654. SMALL CRAFT ADVISORY UNTIL 6 AM EST TUESDAY FOR ANZ656-658. && $$ SYNOPSIS...ALB/MPR NEAR TERM...ALB/MPR SHORT TERM...MPR LONG TERM...LSA AVIATION...LKB MARINE...LSA TIDES/COASTAL FLOODING...AKQ CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
135 AM EST MON FEB 23 2015 .SYNOPSIS... A COLD AND DRY AIR MASS SETTLES IN TO START THE WEEK. ANOTHER COLD FRONT SWINGS THROUGH THE REGION TUESDAY NIGHT. && .NEAR TERM /THROUGH TODAY/... CURRENT MOSAIC RADAR IMAGERY SHOWS LIGHT SNOW CONTINUING TO STREAM ACROSS THE FORECAST AREA...ASSOCIATED WITH A RELATIVELY DRY COLD FRONT BI-SECTING THE CWA. BEHIND THE FRONT...PRECIPITATION REGIME TURNS SHOWERY WITH STRIATIONS OF LIGHT SNOW SHOWERS STRETCHING FROM THE SOUTHERN SHORE OF LAKE ERIE INTO OUR FAR ERN OHIO COUNTIES. THE LATEST RAP HAS A GOOD HANDLE ON BOTH THE TIMING OF THE SNOW ALONG THE FRONT AND THE LOCATION/TIMING ON THE SHOWERS BEHIND IT. CONTINUED TO FOLLOW THE RAP THROUGH THE EARLY MORNING AS THE MID AND UPPER LEVEL MOISTURE OVERRUNS THE LOW LEVEL MOISTURE AND THE SNOW CEASES. TEMPERATURES WILL CONTINUE TO FALL THROUGH THE EARLY MORNING...BOTTOMING OUT BELOW ZERO NORTH OF I-80...AND THE SINGLE DIGITS ABOVE ZERO FOR MOST OTHER LOCATIONS. AS THE COLD FRONT CROSSES...A SUBTLE WIND SHIFT IS NOTED...BUT AN INCREASE IN FLOW SPEED IS THE BIGGER IMPACT. ALREADY SEEING WIND CHILLS INTO THE SINGLE DIGITS. SHOULD SEE WIND CHILL VALUES BELOW -10 IN THE NEXT FEW HOURS LEADING TO YET ANOTHER FRIGID MORNING. OPTIMISTICALLY CUTTING BACK ON CLOUDS THIS MORNING AND THROUGH THE BALANCE OF MONDAY. BEHIND THE EXITING FRONT...COPIOUS DRY AIR WILL CLEAR THE COLUMN. ALL UPSTREAM OBSERVATIONS SHOW CLEAR SKIES AND WITH LAKE ERIE COMPLETELY FROZEN...NO DOWNSTREAM LAKE-INDUCED CLOUDS ARE EXPECTED. A DECEPTIVELY SUNNY DAY IS EXPECTED AS TEMPERATURES WILL REMAIN WELL BELOW AVERAGE. BUMPED HIGHS UP A FEW DEGREES AS THE INCREASINGLY POTENT LATE FEBRUARY SUNSHINE SHOULD MAKE INROADS ON THIS LATEST ARCTIC AIRMASS. TAX && .SHORT TERM /TONIGHT THROUGH 6 PM TUESDAY/... TEMPERATURES WILL PLUMMET BEHIND THE FRONTAL BOUNDARY WITH MORNING LOWS PROJECTED AROUND ZERO...ON AVERAGE...ACROSS THE REGION. CHANGES TO THE PREVIOUS TEMPERATURE FORECAST WERE MINIMAL...BUT TWEAKS WERE BASED PRIMARILY ON CANADIAN AND ADJUSTED MET GUIDANCE WHICH HAS PERFORMED WELL AS OF LATE. PROGGED SURFACE GRADIENTS STILL LOOK SUPPORTIVE OF WIND THAT WOULD RESULT IN A WIND CHILLS DROPPING BELOW THE -10F THRESHOLD ACROSS MUCH OF THE REGION BY EARLY MONDAY MORNING. THE WIND CHILL ADVISORY HAS THUS BEEN EXPANDED TO INCLUDE ALL BUT A FEW COUNTIES TO THE SOUTH OF INTERSTATE 70...AND HAS BEEN SEGMENTED FOR WIND CHILL MAGNITUDE AND TIMING. THE COLD WEATHER WILL CONTINUE INTO MONDAY NIGHT...BUT BUILDING HIGH PRESSURE IS EXPECTED TO SLACKEN THE WIND AND PRECLUDE A CONTINUATION OF THE WIND CHILL ADVISORY AS MONDAY EVENING FALLS. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... AN UPPER TROUGH OVER THE NORTHEASTERN CONUS...AND ITS ASSOCIATED SURFACE COLD FRONT...IS PROGGED FOR A LATE TUESDAY NIGHT/EARLY WEDNESDAY PASSAGE. BEST MOISTURE AND UPPER SUPPORT SHOULD REMAIN NORTH OF THE AREA SO MAINTAINED ONLY CHANCE POPS FOR SNOW SHOWERS. A DEAMPLIFIED UPPER PATTERN IS PROGGED TO SET UP FOR THE REMAINDER OF THE PERIOD WITH MAINLY DRY WEATHER UNTIL THE APPROACH AND PASSAGE OF A WEEKEND TROUGH. AFTER A COLD START TEMPERATURES SHOULD BEGIN TO MODERATE BY THE WEEKEND. WPC GUIDANCE DEPICTED A MODEL BLEND SOLUTION SMOOTHING OUT MODEL DIFFERENCES...AND WAS USED WITH A FEW TWEAKS. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... SLOWED THE EXODUS OF THE ARCTIC FRONT AND ASSOCIATED MVFR SNOW/CLOUDS THIS MORNING BY A FEW HOURS...BUT GENERALLY EXPECTING IMPROVEMENT TO VFR BY 12Z. CLOUD COVER SHOULD SCATTER OUT THROUGH MIDDAY WITH TERMINALS ACROSS THE SOUTH SLOWEST TO LOSE THE COVER. WINDS WILL STAY FROM THE NORTH...AND SLOWLY GRADUALLY DISSIPATE THROUGH THE AFTERNOON/EVENING. GENERALLY CLEAR CONDITIONS ARE EXPECTED TONIGHT. TAX OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/... RESTRICTIONS ARE POSSIBLE WITH A TUESDAY NIGHT/WEDNESDAY COLD FRONT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 PM EST THIS EVENING FOR MDZ001. OH...WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST THIS AFTERNOON FOR OHZ039>041-048>050-057>059. PA...WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST THIS AFTERNOON FOR PAZ020-021-029-073-075. WIND CHILL ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ007>009- 013>016-022-023. WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 PM EST THIS EVENING FOR PAZ074-076. WV...WIND CHILL ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 PM EST THIS AFTERNOON FOR WVZ001>003. WIND CHILL ADVISORY FROM 6 AM THIS MORNING TO 7 PM EST THIS EVENING FOR WVZ023-041. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
250 AM EST MON FEB 23 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 305 PM EST SUN FEB 22 2015 A VERY COLD UPPER TROUGH IS SLIDING EAST ACROSS THE UPPER GREAT LAKES REGION THIS AFTERNOON...WITH RAP ANALYZED 850MB TEMPS OF -29C OVER WESTERN LAKE SUPERIOR. THIS HAS LED TO AFTERNOON TEMPERATURES AROUND 25-30 DEGREES BELOW THE NORMAL HIGHS FOR THIS TIME OF YEAR WITH 2PM TEMPERATURES RANGING FROM -10 AT KCMX TO 7 AT KMNM. THE COLD AIR AND A FEW BREAKS IN THE ICE...OR AT LEAST AREAS OF THIN ICE...HAS CONTINUED TO LEAD TO VERY THIN BANDS OF LAKE EFFECT OFF LAKE SUPERIOR IN THE NORTHWEST WIND SNOW BELTS. WHILE THE BANDS HAVE BEEN THIN...OBS AND WEBCAMS HAVE SHOWN THAT THEY CONTINUE TO BE EFFICIENT AT REDUCING VISIBILITIES WITH ALL OF THE CLOUDY WELL BELOW THE DGZ. THOSE VERY LOCALIZED LOWER VISIBILITIES HAVE ALSO BEEN AIDED BY BLOWING SNOW FROM THE GUSTY NORTHWEST WINDS OF 15-30MPH. MEANWHILE...A SURFACE HIGH IS CURRENTLY LOCATED OVER THE EASTERN DAKOTAS AND AN ASSOCIATED SURFACE RIDGE IS NOSING INTO THE UPPER GREAT LAKES. THE HIGH WILL DROP SOUTHEAST INTO THE MID MISSISSIPPI VALLEY TONIGHT...WHICH WILL PUSH A RIDGE ACROSS THE UPPER GREAT LAKES REGION. THIS RIDGE WILL LEAD TO BACKING WINDS THROUGH THE NIGHT...BECOMING SOUTHWESTERLY LATE TONIGHT OVER THE WEST AND MONDAY MORNING OVER THE EAST. THESE BACKING WINDS...ALONG WITH INCREASING SUBSIDENCE...WILL DIMINISH THE LAKE EFFECT POTENTIAL FROM THE LIMITED HEATING FROM LAKE SUPERIOR. THUS...EXPECT SKIES TO BECOME MOSTLY CLEAR THIS EVENING OVER MUCH OF THE AREA AS THE DIURNAL CU DISSIPATE...WITH THE EASTERN U.P. HANGING ON THE LONGEST INTO THE OVERNIGHT HOURS. WHILE THE CLEAR SKIES WILL PROMOTE RADIATIONAL COOLING...THINKING THERE WILL BE ENOUGH MIXING FROM JUST ABOVE THE SURFACE AND THE REMAINING PRESSURE GRADIENT TO KEEP LOWS FROM GETTING AS COLD AS SEEN A FEW DAYS AGO ON THE CLEAR/CALM NIGHTS. BUT WITH THE COLD AIR IN PLACE AND LITTLE REBOUND IN TEMPS TODAY...HAVE LOWS IN THE TEENS AND TWENTIES BELOW ZERO FOR TONIGHT. WHEN COMBINED WITH THE EXPECTED WINDS OF 4-8MPH TONIGHT...WIND CHILL VALUES WILL REMAIN IN THE -25 TO -35 DEGREE RANGE THROUGH MONDAY MORNING. DO HAVE A FEW AREAS WHERE WIND CHILLS WILL BE IN WARNING CRITERIA (GENERALLY OVER IRON COUNTY)...BUT WITH WINDS IN THOSE AREAS ONLY AROUND 5MPH OVERNIGHT...DIDN/T FEEL THAT THE WINDS WERE CLOSE ENOUGH TO OUR 10MPH CRITERIA TO ISSUE THE WARNING. ALSO AM A LITTLE CONCERNED WITH WIND CHILLS REACHING WARNING CRITERIA OVER THE KEWEENAW PENINSULA...AS THEY HAVE BEEN BOUNCING BACK AND FORTH OVER THE -35 CRITERIA LATE THIS MORNING AND INTO THE AFTERNOON. THIS WILL LIKELY CONTINUE THROUGH MUCH OF THE NIGHT AS WINDS BACK AND THE TIGHTEST GRADIENT PIVOTS OVER THAT AREA. EITHER WAY...IT WILL BE VERY COLD ACROSS UPPER MICHIGAN TONIGHT INTO MONDAY MORNING. OVERALL...MONDAY LOOKS TO BE QUIET ACROSS THE AREA AS THE HIGH PRESSURE RIDGE DEPARTS. AFTER A SUNNY START TO THE DAY...MID-HIGH CLOUDS WILL STREAM OVER THE AREA THROUGH THE AFTERNOON AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA LATE MONDAY NIGHT. BUT WITH ABUNDANT DRY AIR BETWEEN 900-700MB...EXPECT THE PRECIPITATION TO STAY OFF TO THE WEST OF UPPER MICHIGAN THROUGH THE LATE AFTERNOON. WINDS WILL GET GUSTY OUT OF THE SOUTHWEST DURING THE AFTERNOON AND ESPECIALLY THE EVENING. THUS...ADDED PATCHY BLOWING SNOW TO SOME AREAS OVER THE WEST DURING THE LATE AFTERNOON. WILL SEE HIGHS REBOUND INTO THE SINGLE DIGITS AND A FEW LOWER TEENS ABOVE ZERO TOMORROW...BUT WITH THE INCREASING WINDS IN THE AFTERNOON IT WILL STILL FEEL VERY COLD. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 250 AM EST MON FEB 23 2015 TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR. WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY- TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO WNW WINDS. SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE. WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR. THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS -25 TO -34F. LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS SHOULD BE MUCH LIGHTER. THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS. LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON- EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS. EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR 20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING OUT OF THE CENTRAL PLAINS/. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1220 AM EST MON FEB 23 2015 A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3 TAF SITES INTO THIS EVNG. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX EARLY THIS MRNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP SUFFICIENTLY ICE COVERED TO LIMIT THE POTENTIAL FOR LES OR EVEN MUCH IN THE WAY OF LK CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY THIS AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG FM THE NW. SN IN ADVANCE OF THIS FNT WL ARRIVE NW-SE LATE THIS EVNG. DRY NATURE OF THE ANTECEDENT AIRMASS WL MAINTAIN VFR CONDITIONS INITIALLY DESPITE THE THICKENING CLD COVER AND ARRIVING -SN. BEST CHC FOR MVFR CONDITIONS BEFORE 24/06Z WL BE AT CMX...WHERE THE PCPN WL ARRIVE EARLIEST. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 305 PM EST SUN FEB 22 2015 HIGH PRESSURE IN THE DAKOTAS WILL MOVES INTO THE MID MISSISSIPPI VALLEY LATE TONIGHT AND MONDAY MORNING...WHILE SHIFTING A RIDGE ACROSS THE UPPER GREAT LAKES REGION. THIS WILL LEAD TO WEAKENING WINDS TONIGHT...BEFORE QUICKLY INCREASING OUT OF THE SOUTHWEST ON MONDAY AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO. THIS WILL LEAD TO SOUTHWESTERLY GALES OF 35-40KTS OVER PORTIONS OF LAKE SUPERIOR MONDAY AFTERNOON/EVENING AND HAVE ISSUED A GALE WARNING FOR MUCH OF WESTERN/CENTRAL LAKE SUPERIOR FOR LATE MONDAY AFTERNOON AND MONDAY NIGHT. THEN AS A COLD FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE MONDAY NIGHT INTO TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST. THERE MAY BE A FEW GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS BELOW 20KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR MIZ001>007-009>014-084-085. LAKE SUPERIOR... GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR LSZ266. GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KF AVIATION...KC MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1221 AM EST MON FEB 23 2015 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 305 PM EST SUN FEB 22 2015 A VERY COLD UPPER TROUGH IS SLIDING EAST ACROSS THE UPPER GREAT LAKES REGION THIS AFTERNOON...WITH RAP ANALYZED 850MB TEMPS OF -29C OVER WESTERN LAKE SUPERIOR. THIS HAS LED TO AFTERNOON TEMPERATURES AROUND 25-30 DEGREES BELOW THE NORMAL HIGHS FOR THIS TIME OF YEAR WITH 2PM TEMPERATURES RANGING FROM -10 AT KCMX TO 7 AT KMNM. THE COLD AIR AND A FEW BREAKS IN THE ICE...OR AT LEAST AREAS OF THIN ICE...HAS CONTINUED TO LEAD TO VERY THIN BANDS OF LAKE EFFECT OFF LAKE SUPERIOR IN THE NORTHWEST WIND SNOW BELTS. WHILE THE BANDS HAVE BEEN THIN...OBS AND WEBCAMS HAVE SHOWN THAT THEY CONTINUE TO BE EFFICIENT AT REDUCING VISIBILITIES WITH ALL OF THE CLOUDY WELL BELOW THE DGZ. THOSE VERY LOCALIZED LOWER VISIBILITIES HAVE ALSO BEEN AIDED BY BLOWING SNOW FROM THE GUSTY NORTHWEST WINDS OF 15-30MPH. MEANWHILE...A SURFACE HIGH IS CURRENTLY LOCATED OVER THE EASTERN DAKOTAS AND AN ASSOCIATED SURFACE RIDGE IS NOSING INTO THE UPPER GREAT LAKES. THE HIGH WILL DROP SOUTHEAST INTO THE MID MISSISSIPPI VALLEY TONIGHT...WHICH WILL PUSH A RIDGE ACROSS THE UPPER GREAT LAKES REGION. THIS RIDGE WILL LEAD TO BACKING WINDS THROUGH THE NIGHT...BECOMING SOUTHWESTERLY LATE TONIGHT OVER THE WEST AND MONDAY MORNING OVER THE EAST. THESE BACKING WINDS...ALONG WITH INCREASING SUBSIDENCE...WILL DIMINISH THE LAKE EFFECT POTENTIAL FROM THE LIMITED HEATING FROM LAKE SUPERIOR. THUS...EXPECT SKIES TO BECOME MOSTLY CLEAR THIS EVENING OVER MUCH OF THE AREA AS THE DIURNAL CU DISSIPATE...WITH THE EASTERN U.P. HANGING ON THE LONGEST INTO THE OVERNIGHT HOURS. WHILE THE CLEAR SKIES WILL PROMOTE RADIATIONAL COOLING...THINKING THERE WILL BE ENOUGH MIXING FROM JUST ABOVE THE SURFACE AND THE REMAINING PRESSURE GRADIENT TO KEEP LOWS FROM GETTING AS COLD AS SEEN A FEW DAYS AGO ON THE CLEAR/CALM NIGHTS. BUT WITH THE COLD AIR IN PLACE AND LITTLE REBOUND IN TEMPS TODAY...HAVE LOWS IN THE TEENS AND TWENTIES BELOW ZERO FOR TONIGHT. WHEN COMBINED WITH THE EXPECTED WINDS OF 4-8MPH TONIGHT...WIND CHILL VALUES WILL REMAIN IN THE -25 TO -35 DEGREE RANGE THROUGH MONDAY MORNING. DO HAVE A FEW AREAS WHERE WIND CHILLS WILL BE IN WARNING CRITERIA (GENERALLY OVER IRON COUNTY)...BUT WITH WINDS IN THOSE AREAS ONLY AROUND 5MPH OVERNIGHT...DIDN/T FEEL THAT THE WINDS WERE CLOSE ENOUGH TO OUR 10MPH CRITERIA TO ISSUE THE WARNING. ALSO AM A LITTLE CONCERNED WITH WIND CHILLS REACHING WARNING CRITERIA OVER THE KEWEENAW PENINSULA...AS THEY HAVE BEEN BOUNCING BACK AND FORTH OVER THE -35 CRITERIA LATE THIS MORNING AND INTO THE AFTERNOON. THIS WILL LIKELY CONTINUE THROUGH MUCH OF THE NIGHT AS WINDS BACK AND THE TIGHTEST GRADIENT PIVOTS OVER THAT AREA. EITHER WAY...IT WILL BE VERY COLD ACROSS UPPER MICHIGAN TONIGHT INTO MONDAY MORNING. OVERALL...MONDAY LOOKS TO BE QUIET ACROSS THE AREA AS THE HIGH PRESSURE RIDGE DEPARTS. AFTER A SUNNY START TO THE DAY...MID-HIGH CLOUDS WILL STREAM OVER THE AREA THROUGH THE AFTERNOON AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH THE AREA LATE MONDAY NIGHT. BUT WITH ABUNDANT DRY AIR BETWEEN 900-700MB...EXPECT THE PRECIPITATION TO STAY OFF TO THE WEST OF UPPER MICHIGAN THROUGH THE LATE AFTERNOON. WINDS WILL GET GUSTY OUT OF THE SOUTHWEST DURING THE AFTERNOON AND ESPECIALLY THE EVENING. THUS...ADDED PATCHY BLOWING SNOW TO SOME AREAS OVER THE WEST DURING THE LATE AFTERNOON. WILL SEE HIGHS REBOUND INTO THE SINGLE DIGITS AND A FEW LOWER TEENS ABOVE ZERO TOMORROW...BUT WITH THE INCREASING WINDS IN THE AFTERNOON IT WILL STILL FEEL VERY COLD. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 356 PM EST SUN FEB 22 2015 PATTERN OF HIGH AMPLITUDE UPR RIDGE OVER THE ERN PACIFIC/WRN NAMERICA AND DEEP TROF OVER CENTRAL AND ERN NAMERICA WL PERSIST THRU MUCH OF THE WEEK...RESULTING IN A CONTINUED NW FLOW ALOFT THAT WL BRING ARCTIC SURGES INTO THE UPPER LKS THRU MID WEEK. TOWARD THE END OF THE WEEK THOUGH...FALLING HGTS OVER THE W WL ALLOW FOR A MORE ZONAL FLOW AND SOME AIRMASS MODERATION. BUT WITH DRY HI PRES FCST TO BE DOMINATING...LOW TEMPS MAY STILL BE QUITE COLD DESPITE THE MORE SEASONABLE H85 AND DAYTIME TEMPS. MON NGT/TUE...SHRTWV AND ACCOMPANYING SFC LOW DESCENDING SE INTO FAR NW ONTARIO BY MON EVNG ARE FCST TO SLIDE JUST NE OF LK SUP DURING THIS TIME...WITH ATTENDANT COLD FROPA MOVING OVER UPR MI LATE MON NIGHT AND TUE MRNG. SOME LIGHT SN IN THE WAA/ISENTROPIC ASCENT PATTERN AHEAD OF THIS DISTURBANCE WL OVERSPREAD UPR MI FM THE NW ON MON NGT AND PERSIST INTO TUE MRNG BEFORE THE COLD FROPA. SINCE THE MSTR INFLOW WL BE RATHER UNIMPRESSIVE...WITH MIXING RATIOS OF 1-1.5 G/KG FCST ON 280K ISENTROPIC SFC...AND VERY DRY ANTECEDENT AIRMASS IN PLACE WHICH WL TAKE TIME TO MOISTEN...ACCOMPANYING SN ACCUMS SHOULD BE LIMITED TO NO MORE THAN 1 TO 2 INCHES FOR MOST OF CWA WITH MAYBE A FEW LOCATIONS SEEING 3-4 INCHES FAR EAST AND OVER TIP OF KEWEENAW...WHERE HIGHER POPS/QPF WL BE MAINTAINED CLOSER TO THE SHRTWV TRACK...LONGER DURATION OF ISENTROPIC ASCENT AND AREA OF STRONGER DEEP LAYER Q-VECT CONV. ALTHOUGH MODELS SNDGS INDICATE THE DGZ TO BE RATHER DEEP AND INTERSECTING MUCH OF THE ASSOCIATED UVV...STRONG WINDS THROUGH THE MUCH OF THE LAYER MIGHT BREAK UP THE DENDRITES TO A CERTAIN EXTENT. BUT AT SAME TIME...THE SMALLER FLAKES WOULD BE MORE EFFICIENT AT RESTRICTING VSBY WHILE BEING BLOWN ABOUT BY THE GUSTY VEERING WINDS OCCURRING UNDER THE TIGHT PRES GRADIENT AHEAD OF THE COLD FRONT. WITH H85 THERMAL RDG OVER UPR MI ON MON NGT AND THE GUSTY WINDS...EXPECT RELATIVELY HIGH MIN TEMPS. WSHFT TO THE NW FOLLOWING THE TUE MORNING COLD FROPA WL DRAG ANOTHER ARCTIC AIRMASS BACK INTO THE CWA IN THE AFTN...DROPPING H85 TEMPS TO -20C OR COLDER AGAIN BY 00Z WED AND ALLOWING FOR AT LEAST SCATTERED LES TO DEVELOP IN WHATEVER BREAKS THERE ARE IN LAKE SUPERIOR ICE COVER. TUE NGT INTO WED NIGHT...MEDIUM RANGE GUIDANCE FCSTS H85 TEMPS TO FALL AS LO AS -28C TO -30C AROUND 12Z WED IN COLD NNW FLOW AHEAD OF THE NEXT CANADIAN HIGH PRES BUILDING TOWARD THE NRN PLAINS. THERE MAY BE SOME LES OFF BREAKS IN THE EXTENSIVE ICE COVER...BUT THE BIGGEST STORY WL BE WIND CHILLS AT LEAST REACHING INTO ADVY CRITERIA TUE NIGHT INTO WED MORNING AS 950 MB WINDS ARE FCST AOA 30 KTS DURING THE DESTABILIZING PERIOD OF CAA THAT WL DROP MIN TEMPS BLO ZERO AGAIN. AFTER HIGHS POSSIBLY STRUGGLING TO REACH ABV ZERO OVER THE NW CWA ON WED...ANOTHER BITTER COLD NIGHT IS IN STORE FOR WED NIGHT WITH DOUBLE DIGIT BLO ZERO READINGS LIKELY OVER A GOOD PORTION OF THE CWA. THU INTO SUN...THE ARCTIC HI OVER SCENTRAL CANADA ON WED IS FCST TO DRIFT SLOWLY TO THE ESE REACHING THE NRN PLAINS ON THU...AND THE MID MS VALLEY AND LOWER GREAT LAKES/OH RIVER VALLEY ON FRI BEFORE REACHING THE MID-ATLANTIC STATES ON SAT UNDER A PATTERN OF SLOWLY RISING 5H HGTS IN THE GREAT LAKES DOWNSTREAM OF TROFFING OVER WRN NAMERICA. THE RESULT WL BE A PERIOD OF MAINLY DRY WX UNDER DOMINANT SFC HIGH PRES RIDGE. ALTHOUGH THERE MAY BE SOME LES MAINLY E OF MARQUETTE INTO THU WHILE THE LLVL FLOW IS STILL NW...BACKING WINDS TOWARD THE W AND THEN SW WL SHIFT ANY REMAINING LES OUT INTO LK SUP BY LATE THU NIGHT. H85 TEMPS ARE FCST TO MODERATE TO -15C TO -17C BY FRI/SAT...ALLOWING DAYTIME TEMPS TO WARM NEAR 20F UNDER A GOOD DEAL OF SUNSHINE. HOWEVER...STILL EXPECT VERY COLD OVERNIGHT TEMPS (BLO ZERO) AT LEAST THU NIGHT AND FRI NIGHT AS FCST PWAT IS LOWER THAN .10 INCH UNDER LIGHT WINDS. MORE CLDS AND LIGHT MAY ARRIVE SAT NIGHT INTO SUN IN ADVANCE OF THE NEXT APPROACHING LOW PRES TROF. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1220 AM EST MON FEB 23 2015 A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3 TAF SITES INTO THIS EVNG. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX EARLY THIS MRNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP SUFFICIENTLY ICE COVERED TO LIMIT THE POTENTIAL FOR LES OR EVEN MUCH IN THE WAY OF LK CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY THIS AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG FM THE NW. SN IN ADVANCE OF THIS FNT WL ARRIVE NW-SE LATE THIS EVNG. DRY NATURE OF THE ANTECEDENT AIRMASS WL MAINTAIN VFR CONDITIONS INITIALLY DESPITE THE THICKENING CLD COVER AND ARRIVING -SN. BEST CHC FOR MVFR CONDITIONS BEFORE 24/06Z WL BE AT CMX...WHERE THE PCPN WL ARRIVE EARLIEST. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 305 PM EST SUN FEB 22 2015 HIGH PRESSURE IN THE DAKOTAS WILL MOVES INTO THE MID MISSISSIPPI VALLEY LATE TONIGHT AND MONDAY MORNING...WHILE SHIFTING A RIDGE ACROSS THE UPPER GREAT LAKES REGION. THIS WILL LEAD TO WEAKENING WINDS TONIGHT...BEFORE QUICKLY INCREASING OUT OF THE SOUTHWEST ON MONDAY AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO. THIS WILL LEAD TO SOUTHWESTERLY GALES OF 35-40KTS OVER PORTIONS OF LAKE SUPERIOR MONDAY AFTERNOON/EVENING AND HAVE ISSUED A GALE WARNING FOR MUCH OF WESTERN/CENTRAL LAKE SUPERIOR FOR LATE MONDAY AFTERNOON AND MONDAY NIGHT. THEN AS A COLD FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE MONDAY NIGHT INTO TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST. THERE MAY BE A FEW GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS BELOW 20KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR MIZ001>007-009>014-084-085. LAKE SUPERIOR... GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR LSZ266. GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...VOSS AVIATION...KC MARINE...SRF
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
332 AM EST MON FEB 23 2015 .SYNOPSIS... RAIN ASSOCIATED WITH A COLD FRONTAL PASSAGE OVERNIGHT WILL BE LIGHT TONIGHT. WEAK LOW PRESSURE WILL MOVE ALONG THE STALLED FRONT LATER TODAY...SPREADING MORE SIGNIFICANT RAIN NORTHWARD. COLD AIR WILL RETURN THIS EVENING AS ARCTIC HIGH PRESSURE SNEAKS BACK ACROSS THE REGION. COLD AND UNSETTLED WEATHER IS EXPECTED DURING THE UPCOMING WEEK AS CHILLY HIGH PRESSURE AND GULF MOISTURE INTERACT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 PM SUNDAY...SCATTERED AREAS OF RAIN IS LEADING A FRONTAL BOUNDARY THAT WILL SLOWLY PUSH OFF THE COAST BY MORNING. THE AREA OF RAIN IS PRODUCING TOTAL OF LESS THAN A TENTH OF AN INCH. THE LATEST RUN OF THE HRRR IS SHOWING THE COVERAGE OF THE RAIN BECOMING MORE WIDESPREAD OVERNIGHT. TEMPERATURES ARE EXPECTED TO FALL ONLY TO AROUND 40 IN THE NORTHWEST TO THE UPPER 40S SOUTH AND WEST OF MYRTLE BEACH. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...PERIOD BEGINS WITH FRONT STALLED ACROSS THE FL PENINSULA BUT ITS EXACT LOCATION REMAINS SOMEWHAT IN QUESTION. MOST OF THE GUIDANCE HAS THIS FRONT STALLED ACROSS CENTRAL OR SOUTHERN FL WITH ONLY THE NAM KEEPING IT FARTHER NORTH. WEAK SURFACE WAVE WILL DEVELOP ALONG THE FRONT AND MOVE SLOWLY EAST-NORTHEAST. THIS FEATURE HELPS SPREAD PRECIP OVER THE AREA TUE INTO TUE NIGHT AS IT PASSES OFF THE CAROLINA COAST. ISENTROPIC LIFT WILL BE ONGOING TUE IN A ENVIRONMENT FULL OF LOW LEVEL MOISTURE. THERMAL PROFILES IN MOST OF THE GUIDANCE SUPPORTS ALL SNOW AT FIRST. SOUTHERN AREAS WILL TRANSITION TO A WINTRY MIX WHILE NORTHERN LOCATIONS REMAIN IN AN ALL FROZEN REGIME. AT THIS POINT SOUNDINGS DO NOT SUPPORT SIGNIFICANT AMOUNTS OF ZR BUT MUCH CAN CHANGE BETWEEN NOW AND THEN. THE BULK OF THE MOISTURE WILL REMAIN SOUTH AND EAST OF THE AREA WITH INLAND MOST ZONES LIKELY TO STAY DRY BUT UNDER CLOUDY SKIES. WED STARTS OFF DRY BUT NEXT SOUTHERN STREAM SYSTEM...WHICH IS MORE POTENT THAN THE PREVIOUS ONE...WILL BE MOVING ALONG THE GULF COAST. TRACK OF THE SURFACE FEATURE...ALONG THE REMAINS OF THE STALLED SURFACE BOUNDARY...WILL BE ACROSS NORTHERN FL WED AND UP THE EAST COAST WED NIGHT. THE QUESTION IS HOW CLOSE WILL THE LOW PASSES. THE GFS/NAM/CANADIAN HAVE A WEAKER SHORTWAVE COMPARED TO THE ECMWF AND THUS A SLIGHTLY LESS AMPLIFIED MID LEVEL PATTERN. THIS KEEPS THE LOW FARTHER OFF THE COAST WHICH RESULTS IN A LITTLE LESS PRECIP IN THE AREA. CONTINUE TO FAVOR THIS SOLUTION GIVEN THE NATURE OF THE PATTERN AND THE LOCATION OF THE BAROCLINIC ZONE. WORTH NOTING THAT EITHER SOLUTION OPENS UP THE POTENTIAL FOR FROZEN PRECIP LATE WED NIGHT AS STRONG NORTHERLY FLOW ON THE WEST SIDE OF THE DEEPENING LOW BRINGS COLDER AIR INTO THE REGION. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 3 AM MONDAY...DEEPENING LOW PRESSURE WILL BE PASSING OFF THE CAROLINA COAST AS THE PERIOD BEGINS WITH PRECIP LIKELY ONGOING ACROSS THE AREA. THERE IS POTENTIAL FOR FROZEN PRECIP EARLY THU...BUT UNCERTAINTY REMAINS HIGH. THE FIRST ISSUE TO SORT OUT IS HOW MUCH PRECIP WILL BE LINGERING ACROSS THE AREA. GFS AND CANADIAN SOLUTIONS...WHICH PASS THE LOW FARTHER OFF THE COAST INDICATE PRECIP WILL BE WINDING DOWN AS THE PERIOD BEGINS...THOUGH WITH COLDER AIR ALREADY FILTERING IN AT THE LOWER LEVELS. THE ECMWF HAS THE LOW CLOSER TO THE COAST...WHICH KEEPS PRECIP IN THE FORECAST LONGER BUT BECAUSE IT IS SLOWER IT HAS TEMPS SLIGHTLY WARMER THU MORNING. AS IS THE CASE WITH THE FASTER SOLUTION COLDER/DRIER LOW LEVEL AIR DOES WORK ITS WAY IN AS THE PRECIP IS ENDING. MODELS CONTINUE TO TREND DRIER FOR THE END OF THE WEEK WITH ALL OF THE MEDIUM RANGE NOW SHOWING A SPRAWLING 1040MB HIGH DROPPING IN FROM THE UPPER MIDWEST FRI. THE HIGH SHIFTS OVER NEW ENGLAND SAT...EXPANDING DOWN THE EAST ON SUN BEFORE FINALLY PUSHING EAST MON. THE AGREEMENT BETWEEN THE GFS/ECMWF/CANADIAN IS ACTUALLY QUITE SCARY GIVEN THE MIDWEEK NIGHTMARE BUT THE CONTINUED TREND OF DRYING THE FORECAST DOES INCREASE CONFIDENCE SO HAVE TRENDED LATE WEEK FORECAST IN THIS DIRECTION. TEMPERATURES BELOW TO WELL BELOW CLIMO FOR MUCH OF THE PERIOD WILL APPROACH SEASONABLE AS THE PERIOD ENDS. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... AS OF 06Z...EXPECT PCPN IN THE FORM OF LIGHT RAIN TO STREAM ACROSS THE FORECAST AREA BOTH ALONG AND BEHIND THE COLD FRONTAL BOUNDARY. MOISTURE WILL CONTINUE TO FEED ALONG THE FRONT AS ASSOCIATED UPPER LEVEL DISTURBANCE RIDES ALONG THE FRONT AND WILL ENHANCE THE RAINFALL DURING THE PRE-DAWN MON HOURS INTO DAYTIME MON MORNING. IFR AND POSSIBLY LIFR FROM BOTH CEILINGS AND VSBY FROM BR AND FG WILL LIKELY DOMINATE ALL TERMINALS THROUGH THE PRE- DAWN MON HOURS...WITH A SLOW IMPROVEMENT DURING DAYTIME MON MORNING INTO THE AFTERNOON AS THE FRONT DROPS FURTHER SOUTH...ENDING THE THREAT FOR PCPN WITH BOTH VSBY AND CEILINGS IMPROVING. IMMEDIATELY AFTER THE CFP...WINDS WILL VEER TO 360-020 AT 5 TO 10 KT...INCREASING DURING MONDAY TO 10 TO 20 KT...WITH SOME GUSTS IN THE 20S ESPECIALLY ACROSS THE COASTAL TERMS. THIS IN RESPONSE TO THE COMBINED EFFORTS OF COLD AIR ADVECTION AND A TIGHTENED SFC PRESSURE GRADIENT. EXTENDED OUTLOOK...WAVES OF LOW PRESSURE TO AFFECT THE LOCAL AREA DURING THE EXTENDED PERIOD...RESULTING WITH POSSIBLE LIFR/IFR/MVFR CONDITIONS. && .MARINE... .NEAR TERM /THROUGH TONIGHT/... AS OF 930 PM SUNDAY...WINDS ARE RELATIVELY LIGHT OVER THE WATERS WITH SEAS RANGING FROM 2 TO 4 FEET. FRYING PAN SHOALS IS NOW REPORTING SEAS DOWN TO 5 FEET JUST OUTSIDE THE COASTAL WATERS. A LIGHT RAIN IS EXPECTED OVERNIGHT AS A COLD FRONT SLOWLY APPROACHES THE WATERS BY DAYBREAK. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 3 AM MONDAY...STRONG WINDS PRIOR TO THE START OF THE PERIOD WILL HAVE BUILT SEAS HIGH ENOUGH TO LIKELY REQUIRE SCA INTO AT LEAST THE FIRST HALF OF TUE MORNING. NORTHERLY FLOW WILL BE WEAKENING TUE AS SURFACE HIGH TO THE NORTH WEAKENS AND GRADIENT GRADUALLY RELAXES. LOW PRESSURE WILL PASS SOUTHEAST OF THE WATERS TUE EVENING...BACKING WINDS FROM NORTHEAST TO WEST-SOUTHWEST. GRADIENT WILL FURTHER WEAKEN TUE NIGHT AND SPEEDS WILL DROP BELOW 10 KT. PERIOD OF LIGHT OFFSHORE FLOW WILL BE SHORT LIVED AS NEXT SOUTHERN STREAM SYSTEM BEGINS TO AFFECT THE GRADIENT WED. NORTHERLY FLOW WILL DEVELOP AS EARLY AS MIDDAY WED WITH SPEEDS INCREASING WED NIGHT AHEAD OF ADVANCING LOW...POSSIBLY REQUIRING HEADLINES WED NIGHT. LONG TERM /THURSDAY THROUGH FRIDAY/... AS OF 3 AM MONDAY...STRONG NORTHEAST FLOW IN THE WAKE OF EXITING LOW PRESSURE SYSTEMS MAY REQUIRE SCA HEADLINES FOR MUCH IF NOT ALL OF THE PERIOD. THE FIRST LOW WILL BE LIFTING NORTHEAST AS THE PERIOD BEGINS. THE SECOND WILL PASS A BIT FARTHER OFFSHORE FRI MORNING BUT WILL BE A LITTLE STRONGER. THESE SYSTEMS ALONG WITH A SPRAWLING 1040MB HIGH BUILDING IN FROM THE UPPER MIDWEST WILL MAINTAIN NORTHEAST FLOW AROUND 20 KT AND KEEP SEAS OVER 6 FT. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 PM EST TUESDAY FOR AMZ250-252-254-256. && $$ NEAR TERM...DRH SHORT TERM...III LONG TERM...III AVIATION...DCH
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
107 AM EST MON FEB 23 2015 .SYNOPSIS... A MILD AND MOIST AIR MASS WILL LIE ACROSS THE AREA INTO TONIGHT. RAIN ASSOCIATED WITH A COLD FRONTAL PASSAGE WILL BE LIGHT TONIGHT...BUT WEAK LOW PRESSURE WILL MOVE ALONG THE STALLED FRONT...SPREADING MORE SIGNIFICANT RAIN NORTHWARD ON MONDAY. COLD AIR WILL RETURN LATE MONDAY AS ARCTIC HIGH PRESSURE SNEAKS BACK ACROSS THE REGION INTO TUE. COLD AND UNSETTLED WEATHER IS EXPECTED DURING THE UPCOMING WEEK AS CHILLY HIGH PRESSURE AND GULF MOISTURE INTERACT. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... AS OF 930 PM SUNDAY...SCATTERED AREAS OF RAIN IS LEADING A FRONTAL BOUNDARY THAT WILL SLOWLY PUSH OFF THE COAST BY MORNING. THE AREA OF RAIN IS PRODUCING TOTAL OF LESS THAN A TENTH OF AN INCH. THE LATEST RUN OF THE HRRR IS SHOWING THE COVERAGE OF THE RAIN BECOMING MORE WIDESPREAD OVERNIGHT. TEMPERATURES ARE EXPECTED TO FALL ONLY TO AROUND 40 IN THE NORTHWEST TO THE UPPER 40S SOUTH AND WEST OF MYRTLE BEACH. && .SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/... AS OF 330 PM SUNDAY...WAVE OF LOW PRESSURE RIDING ALONG LINGERING FRONT MON MORNING WILL MOVE OUT OF AREA MON AFTN AS HIGH PRESSURE BUILDS DOWN FROM THE NORTHWEST. BEST LIFT WILL RUN FROM SOUTHWEST TO NORTHEAST ALONG BOUNDARY AS IT SHIFTS FARTHER SOUTH THROUGH THE DAY. THEREFORE THE GREATEST POPS WILL BE IN THE MORNING...FAIRLY WIDESPREAD ACROSS MUCH OF THE AREA AND THEN DIMINISHING THROUGH THE AFTERNOON AS DIGGING MID TO UPPER TROUGH AND HIGH PRESSURE PUSH FRONT SOUTHWARD. EXPECT A COOL RAIN AS TEMPS DROP FROM MID 40S IN THE MORNING DOWN TO 30S BY AFTN. LATEST SOUNDINGS KEEP SATURATED COLUMN ABOVE FREEZING UNTIL MON AFTN INTO EARLY EVE. ONCE COLUMN GOES BELOW FREEZING IT DRIES OUT...LEAVING ONLY A THIN SATURATED LAYER BETWEEN 6 TO 7 K FT AFTER 00Z ON NAM SOUNDING. THEREFORE WILL FOLLOW PREVIOUS FORECAST KEEPING POPS OUT OF FORECAST ONCE FZN PCP IS POSSIBLE LATE MONDAY. COASTAL CAROLINAS WILL REMAIN AT THE BASE OF A VERY BROAD UPPER TROUGH THROUGH REMAINDER OF THE PERIOD AS COOL SFC HIGH EXTENDS DOWN FROM THE NORTH. FRONT WILL LINGER FROM SW TO NE SOUTH OF FORECAST AREA WITH COOL AIR LOCKED IN PLACE MON NIGHT THROUGH TUES. TEMPS MONDAY NIGHT WILL FALL INTO THE 20S IN PLENTY OF CAA. TEMPS AT H85 DROP FROM AROUND 7 C MON MORNING DOWN TO -3C BY TUES MORNING. MODELS CONTINUE TO SHOW A PERTURBATION MOVING ACROSS THE CAROLINAS WITH ANOTHER WAVE OF LOW PRESSURE RIDING ALONG THE FRONT OVERNIGHT MONDAY INTO TUES AS THE FRONT STARTS LIFTING NORTH. NAM IS MOST AGGRESSIVE IN BRINGING MOISTURE AND LIFT NORTH EARLY IN THE DAY ON TUES. FOR NOW HAVE INCLUDED SLIGHT CHC UP THROUGH PORTIONS OF FLORENCE ACROSS TO THE GRAND STRAND AND SOUTH INITIALLY AND SPREAD NORTH REMAINING ALIGNED MORE ALONG THE COAST LATER ON TUES. HAVE INCLUDED SOME MIXED PCP AS SOUNDINGS REMAIN BELOW ZERO UP THROUGH THE COLUMN MON NIGHT INTO EARLY TUES WITH A WARM NOSE DEVELOPING INTO THE DAY BUT COLD TEMPS HOLDING ON. AS FRONT TRIES TO MOVE NORTH EXPECT PCP TO SPREAD FARTHER NORTH ON TUES. SHOULD GET PUSHED SOUTH AND EAST AS ANOTHER FRONT MOVES IN FROM THE WEST BY WED MORNING. TEMPS SHOULD REMAIN COOL THROUGH THE PERIOD. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 300 PM SUNDAY...LARGE...BUT NOT EXCEPTIONALLY DEEP...TROUGH WILL PERSIST ACROSS THE EAST INTO THE UPCOMING WEEKEND MAINTAIN COLD AND UNSETTLED CONDITIONS FOR MUCH OF THE EXTENDED. COLD FRONT STALLED WELL SOUTH OF THE AREA WILL SERVE AS THE BAROCLINIC GRADIENT ALONG WHICH AN ACTIVE SOUTHERN STREAM WILL SPAWN SEVERAL WAVES OF LOW PRESSURE. WHILE NONE OF THESE WILL BE IMPRESSIVELY STRONG...EACH ONE WILL BRING AT LEAST A CHANCE OF PRECIP TO THE AREA. TWO QUESTIONS WILL SURROUND EACH PASSING WAVE OF LOW PRESSURE HOWEVER...HOW MUCH PRECIP WILL EXTEND NORTH FROM THE LOW...AND WHETHER COLD ENOUGH AIR WILL BE IN PLACE FOR MIXED P-TYPE. THE FIRST OF THESE...WEDNESDAY NIGHT AND THURSDAY...LOOKS NOW TO BE THE MOST SIGNIFICANT OF THE WEEK. GUIDANCE IS TRACKING THIS SURFACE LOW A LITTLE FURTHER WEST THAN PREVIOUS RUNS...AND THUS SLINGING MORE PRECIP INTO THE CAROLINAS. ADMITTEDLY...THE E-W ORIENTED BAROCLINIC ZONE DOES NOT`T SUPPORT A VERY FAR WEST TRACK AND WILL LEAN MORE ON THE DRIER GFS...BUT WIDESPREAD CLOUDS WITH PERIODS OF PRECIP ARE POSSIBLE WEDNESDAY NIGHT INTO THURSDAY. WITH COLD HIGH PRESSURE IN PLACE RAIN COULD MIX WITH SOME FREEZING/FROZEN PRECIP...EVEN THOUGH RAIN IS EXPECTED TO BE THE PRIMARY P-TYPE. THE ECMWF...WHICH IS MORE ROBUST WITH ITS PRECIP...IS ALSO COLDER...BUT EVEN THE GFS DEPICTS A PERIOD OF MIXED PRECIP. LOCAL TOP-DOWN METHODOLOGY PRODUCES PRIMARILY RAIN AS EXPECTED...BUT HAVE LEFT A PERIOD OF MIX PRECIP...RAIN AND SNOW WITH SNOW ONLY FAR NW...LATE WED NIGHT. QPF WILL BE LIGHT AND POP IS LOW...BUT SNOWFLAKES ARE POSSIBLE WED NIGHT BEFORE TEMPS WARM TO SUPPORT ONLY RAIN DURING THURSDAY. A PERIOD OF DRIER WEATHER IS EXPECTED LATE THURSDAY INTO FRIDAY...BEFORE ANOTHER LOW PRESSURE MOVES ALONG THE STALLED BOUNDARY TO THE SOUTH. HOWEVER...EVEN DURING THIS "DRIER" PERIOD A SCHC POP REMAINS WARRANTED DUE TO WAVES OF LOW PRESSURE ALONG THE OFFSHORE BAROCLINIC GRADIENT - AND THERE IS LOW CONFIDENCE IN THE TIMING/TRACK OF THESE FEATURES. THE PAST FEW DAYS...ECMWF/GFS HAD SHOWN GOOD AGREEMENT IN BRINGING MORE SIGNIFICANT PRECIP LOCALLY FRIDAY INTO SATURDAY...MUCH OF WHICH WOULD BE OF THE FREEZING-TO-LIQUID TRANSITION VARIETY. TODAY...GUIDANCE HAS BACKED OFF CONSIDERABLY...WHICH MAY MAKE SENSE DUE TO THE EXPECTED QUICK E/NE TRACK OF SURFACE FEATURES. STILL...AM INCLINED TO MAKE ONLY MINIMAL CHANGES TO THE FRI/SAT TIMEFRAME AS THIS REPRESENTS A NEW SOLUTION...AND WILL LEAVE LOW MENTIONABLE POP WITH MIXED P-TYPE. BY SUNDAY THE LONGWAVE TROUGH WILL BEGIN TO ERODE...FINALLY...BRINGING BRIGHTER WEATHER AND MORE SEASONABLE TEMPERATURES AFTER THE FIRST 4 DAYS OF THE EXTENDED CONTINUE WELL BELOW NORMAL. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 06Z...EXPECT PCPN IN THE FORM OF LIGHT RAIN TO STREAM ACROSS THE FORECAST AREA BOTH ALONG AND BEHIND THE COLD FRONTAL BOUNDARY. MOISTURE WILL CONTINUE TO FEED ALONG THE FRONT AS ASSOCIATED UPPER LEVEL DISTURBANCE RIDES ALONG THE FRONT AND WILL ENHANCE THE RAINFALL DURING THE PRE-DAWN MON HOURS INTO DAYTIME MON MORNING. IFR AND POSSIBLY LIFR FROM BOTH CEILINGS AND VSBY FROM BR AND FG WILL LIKELY DOMINATE ALL TERMINALS THROUGH THE PRE- DAWN MON HOURS...WITH A SLOW IMPROVEMENT DURING DAYTIME MON MORNING INTO THE AFTERNOON AS THE FRONT DROPS FURTHER SOUTH...ENDING THE THREAT FOR PCPN WITH BOTH VSBY AND CEILINGS IMPROVING. IMMEDIATELY AFTER THE CFP...WINDS WILL VEER TO 360-020 AT 5 TO 10 KT...INCREASING DURING MONDAY TO 10 TO 20 KT...WITH SOME GUSTS IN THE 20S ESPECIALLY ACROSS THE COASTAL TERMS. THIS IN RESPONSE TO THE COMBINED EFFORTS OF COLD AIR ADVECTION AND A TIGHTENED SFC PRESSURE GRADIENT. EXTENDED OUTLOOK...WAVES OF LOW PRESSURE TO AFFECT THE LOCAL AREA DURING THE EXTENDED PERIOD...RESULTING WITH POSSIBLE LIFR/IFR/MVFR CONDITIONS. && .MARINE... .NEAR TERM /THROUGH TONIGHT/... AS OF 930 PM SUNDAY...WINDS ARE RELATIVELY LIGHT OVER THE WATERS WITH SEAS RANGING FROM 2 TO 4 FEET. FRYING PAN SHOALS IS NOW REPORTING SEAS DOWN TO 5 FEET JUST OUTSIDE THE COASTAL WATERS. A LIGHT RAIN IS EXPECTED OVERNIGHT AS A COLD FRONT SLOWLY APPROACHES THE WATERS BY DAYBREAK. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 330 PM SUNDAY...SMALL CRAFT ISSUED FOR MONDAY THROUGH EARLY TUES AS ARCTIC HIGH PRESSURE BUILDS DOWN BEHIND COLD FRONT. THIS COLD FRONT WILL LINGER SOUTH OF AREA KEEPING TIGHTENED GRADIENT FLOW THROUGH MON NIGHT AND ALONG WITH PLENTY OF CAA...WINDS AND SEAS WILL RAMP UP TO 5 TO 7 FT IN STRONG NORTHERLY FLOW UP AROUND 25 KTS IN OUTER WATERS. THE STRONG N TO OFF SHORE COMPONENT WILL KEEP HIGHEST SEAS AWAY FROM SHORE. WINDS START DECREASING TUE AS ELONGATED SURFACE RIDGE AXIS MOVES TO THE COAST AND GRADIENT RELAXES. LIGHT WINDS LATE TUE CONTINUE TUE NIGHT AS THE WEAK HIGH EXITS NORTHEAST AND WINDS BACK TO WEST-SOUTHWEST. SEAS FALL TO 3 TO 5 FT LATER TUE AND 2 TO 4 FT TUE NIGHT. LONG TERM /WEDNESDAY THROUGH FRIDAY/... AS OF 300 PM SUNDAY...DIFFUSE PRESSURE PATTERN WEDNESDAY LEAVES A WEAK GRADIENT AND LIGHT W-NW WINDS ACROSS THE WATERS. THIS WILL CHANGE RAPIDLY WEDNESDAY NIGHT AND INTO THURSDAY AS A LOW PRESSURE SYSTEM MOVES SE OF THE WATERS. THE LOW TRACK WILL REMAIN OUTSIDE THE COASTAL WATERS...BUT THE GRADIENT AROUND THIS LOW WILL CAUSE NE WINDS TO INCREASE STEADILY...BECOMING 15-20 KTS EARLY THURSDAY. AS THE LOW PULLS AWAY THURSDAY NIGHT...THE GRADIENT WILL REMAIN PINCHED THANKS TO A STALLED COLD FRONT SOUTH OF THE AREA...ALONG WHICH ANOTHER LOW PRESSURE WILL DEVELOP AND MOVE OFF THE COAST FRIDAY. THIS CONTINUES THE NE WINDS AT 15-20 KTS THROUGH THE END OF THE PERIOD. SEAS WEDNESDAY WILL BE JUST 1-3 FT ON THE LIGHT AND VARIABLE WINDS...BUT WILL INCREASE QUICKLY WED NIGHT ON THE INCREASING NE FETCH. WAVE HEIGHTS BUILD TO 4-6 FT THURSDAY MORNING...AND THEN EVEN A LITTLE HIGHER ON FRIDAY...AND AN EXTENDED SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR MOST OF THURSDAY AND FRIDAY. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 PM EST TUESDAY FOR AMZ250-252-254-256. && $$ SYNOPSIS...RGZ NEAR TERM...DRH SHORT TERM...RGZ LONG TERM...JDW AVIATION...DCH
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1155 PM CST SUN FEB 22 2015 .AVIATION... NOT MUCH CHANGE TO THE PREVIOUS TAF PACKAGE WITH REGARDS TO TIMING AND TYPE OF PRECIPITATION EXPECTED OVER THE NEXT 18 HOURS OR SO. SOME LIGHT FREEZING DRIZZLE WILL LINGER ACROSS THE METROPLEX TAF SITES FOR THE NEXT FEW HOURS WITH GENERALLY IFR CEILINGS. THE NEXT ROUND OF PRECIPITATION ASSOCIATED WITH ANOTHER SHORT WAVE IS CURRENTLY DEVELOPING ACROSS THE PERMIAN BASIN AND SHOULD ARRIVE AT THE METROPLEX TAF SITES AROUND SUNRISE. THIS PRECIPITATION WILL MOSTLY BE IN THE FORM OF SLEET. HIGH RES MODEL SOLUTIONS CONTINUE TO INDICATE CONVECTIVE BANDS WITH SOME THUNDER SLEET. THE MOST LIKELY PERIOD FOR SLEET ACROSS THE METROPLEX TERMINALS WILL BE BETWEEN 12 AND 18Z. SLEET CHANCES WILL DECREASE AFTER 18Z EXCEPT FOR WACO WHERE SLEET WILL BE MOST LIKELY MONDAY AFTERNOON. OVERALL CEILINGS WILL REMAIN BETWEEN 700 AND 1000 FT THROUGH THE DAY AND EVENING MONDAY. ALL PRECIPITATION SHOULD END BY 00Z TUESDAY. A NORTH WIND WILL PREVAIL OVERNIGHT AT SPEEDS BETWEEN 15 AND 20 KNOTS SUSTAINED ALONG WITH SOME HIGHER GUSTS. A NORTH WIND WILL CONTINUE ON MONDAY BUT SPEEDS SHOULD DECREASE THROUGH THE DAY AND FALL BELOW 12 KNOTS AFTER SUNSET. 79 && .UPDATE... AS THE FIRST WAVE OF PRECIPITATION ENDS THIS EVENING...A LARGE AREA OF FREEZING DRIZZLE HAS DEVELOPED NORTH TO WEST OF THE DFW METROPLEX INCLUDING TARRANT COUNTY. 850 MB WINDS ARE OUT OF THE EAST OVERRUNNING THE COLD SURFACE AIR...BUT THEY HAVE PREVAILED FROM THIS DIRECTION MOST OF THE EVENING WITHOUT DRIZZLE DEVELOPING EARLIER IN THE NIGHT. THE RAP SHOWS A WEAK SHORTWAVE MOVING OVERHEAD WHICH IS LIKELY PROVIDING ADDITIONAL LIFT FOR THE DRIZZLE TO DEVELOP...IN COMBINATION WITH THE ISENTROPIC LIFT OVER THE COLD SURFACE LAYER. THE RAP SHOWS THIS SHORTWAVE MOVING EAST OF THE REGION BY MIDNIGHT AND EXPECT MOST OF THE DRIZZLE WILL END AROUND THAT TIME. HOWEVER...THE DRIZZLE IS ALREADY AND WILL CREATE A THIN LAYER OF ICE ON ELEVATED SURFACES...METAL OBJECTS...AND LIKELY BRIDGES AND OVERPASSES THAT ALREADY DO NOT HAVE ICE FROM THE FREEZING RAIN/SLEET EARLIER. IN ADDITION...RESIDUAL WATER REMAINING ON ROADWAYS TONIGHT MAY FREEZE OVERNIGHT AS TEMPERATURES FALL INTO THE 20S OVER A GOOD PORTION OF THE REGION. HOWEVER...THE STRONG WINDS WILL CONTINUE THROUGH THE OVERNIGHT HOURS WHICH MAY ALSO HELP TO EVAPORATE ANY WATER ON ROADWAYS...BUT NOT WHERE DRIZZLE IS OCCURRING. THE NEXT WAVE OF PRECIPITATION IS STILL EXPECTED TO ARRIVE BETWEEN 1-3 AM...MOVING IN FROM THE WEST OR SOUTHWEST. NO CHANGES ARE NEEDED TO THE CURRENT WARNING AND ADVISORY PRODUCTS...HOWEVER...IF THE NEXT ROUND OF PRECIPITATION IS SLIGHTLY FARTHER SOUTH THAN THE LATEST GUIDANCE SUGGESTS...IT IS POSSIBLE PORTIONS OF THE ADVISORY MAY HAVE TO BE UPGRADED TO A WARNING DUE TO HIGHER ACCUMULATIONS OF SLEET. UNFORTUNATELY WE WILL HAVE TO WAIT AND MONITOR THE RADAR TRENDS LATE TONIGHT AND EARLY MONDAY MORNING BEFORE BEING ABLE TO CONFIDENTLY MAKE THAT DECISION. 82/JLD && .PREV DISCUSSION... /ISSUED 400 PM CST SUN FEB 22 2015/ ...SIGNIFICANT WINTER STORM TAKING SHAPE FOR OVERNIGHT AND EARLY MONDAY ACROSS NORTH TEXAS... .SIGNIFICANT FORECAST CHANGES... WINTER STORM WARNING START TIME HAS BEEN MOVED UP TO START NOW. WINTER WEATHER ADVISORY START TIME HAS BEEN MOVED UP TO 9PM. SLEET ACCUMULATIONS HAVE BEEN BUMPED UP SLIGHTLY ACROSS THE NORTHWEST PARTS OF THE CWA. ICE ACCUMULATIONS FROM FREEZING RAIN HAVE BEEN NUDGED UP SLIGHTLY BUT REMAIN BELOW WARNING CRITERIA FARTHER SOUTH. HOURLY TEMPERATURE TRENDS HAVE BEEN ADJUSTED TO REFLECT CURRENT POSITION OF COLDER AIR. HIGH TEMPERATURES ON MONDAY HAVE BEEN LOWERED BY 2-3 DEGREES. NO OTHER SIGNIFICANT FORECAST CHANGES THIS AFTERNOON. .TECHNICAL DISCUSSION... MUCH COLDER AIR CONTINUES TO FILTER INTO NORTH TEXAS THIS AFTERNOON WITH SUB FREEZING TEMPERATURES NOW MOVING INTO THE NORTHWEST COUNTIES. PRECIPITATION HAS DIMINISHED IN INTENSITY ACROSS THESE AREAS WHICH SHOULD LIMIT ANY FREEZING RAIN POTENTIAL THROUGH THE EVENING HOURS. FARTHER EAST...A COLD RAIN WILL CONTINUE THROUGH THE EARLY EVENING AS THE FIRST WAVE OF LIFT MOVES TO THE NORTHEAST. TEMPERATURES ARE GENERALLY IN THE MID TO UPPER 30S AND LOWER 40S WHERE THIS PRECIPITATION IS OCCURRING SO NO FREEZING RAIN IS EXPECTED. SOME AREAS HAVE ALREADY PICKED UP CLOSE TO AN INCH OF RAIN BUT THIS INTENSITY WILL DIMINISH THROUGH EVENING. SIGNS OF THE SECOND WAVE OF ASCENT ARE ALREADY BEING INDICATED ON RADAR AND WATER VAPOR IMAGERY ACROSS WEST TEXAS. SOME AREAS OF PRECIPITATION HAVE ALREADY DEVELOPED BUT THIS SHOULD GENERALLY REMAIN SCATTERED OVER THE NEXT SEVERAL HOURS AS THE BETTER FORCING WILL ARRIVE DURING THE OVERNIGHT HOURS. WE ARE EXPECTED TO SEE A LULL IN THE PRECIPITATION LATER THIS EVENING THROUGH MIDNIGHT OR SO...BUT IT WONT BE COMPLETELY VOID OF ACTIVITY. THERE WILL LIKELY BE INTERMITTENT AREAS OF PRECIPITATION THAT DEVELOP IN POCKETS OF STRONGER FORCING THAT STREAM ACROSS NORTH TEXAS IN THE SOUTHWEST FLOW ALOFT. ANY PRECIPITATION THAT DEVELOPS LATE THIS EVENING COULD BE IN THE FORM OF A FREEZING RAIN/SLEET MIX ACROSS THE WEST AND NORTHWEST PARTS OF THE CWA. THE FREEZING LINE WILL SURGE SOUTH THIS EVENING ACROSS THE WESTERN COUNTIES AND IT WILL TAKE A LITTLE LONGER FARTHER EAST. IT SHOULD BE MOVING INTO THE METROPLEX BY 0Z OR A LITTLE LATER. BY 3-4AM...MOST AREAS WITH THE EXCEPTION OF THE SOUTHEAST COUNTIES SHOULD BE AT OR BELOW FREEZING. THE STRONGEST FORCING LOOKS LIKE IT WILL OVERSPREAD NORTH TEXAS IN THE 3-5AM TIMEFRAME WITH WIDESPREAD PRECIPITATION CONTINUING INTO THE MORNING HOURS ON MONDAY. THE COMPACT UPPER LOW SOUTH OF CALIFORNIA IS IN THE PROCESS OF EJECTING NORTHEAST NOW AND ANOTHER DISTURBANCE APPEARS TO BE EMBEDDED IN THE FLOW ACROSS NORTHWEST MEXICO. THESE SEEM TO BE THE FEATURES THAT REALLY PROVIDE THE FORCING FOR ASCENT LATE TONIGHT. RIGHT NOW... WE THINK THE HEAVIEST PRECIPITATION WILL OCCUR ALONG A LINE FROM NEAR EASTLAND TO DFW TO SHERMAN...AND AREAS NORTHWEST OF THERE THROUGH ABOUT 10AM ON MONDAY. LATEST HIGH RESOLUTION TTU-WRF AND 4KM NAM CONTINUE TO YIELD HIGH CONFIDENCE IN THE CURRENT FORECAST AS BOTH CONTINUE TO STRONGLY INDICATE CONVECTIVE ELEMENTS TO THE PRECIPITATION. SREF PLUMES OF MUCAPE AND ANALYSIS OF ALL AVAILABLE FORECAST SOUNDINGS INDICATE THAT ANYWHERE FROM 100-150J/KG OF ELEVATED INSTABILITY WILL BE PRESENT. THIS WILL SUPPORT THUNDERSLEET THROUGH THE MORNING HOURS. BURSTS OF SLEET CAN QUICKLY ACCUMULATE TO AN INCH OR MORE IN A SHORT PERIOD OF TIME. AS OF THIS AFTERNOON...WE THINK THAT MOST AREAS IN THE CURRENT WARNING WILL SEE BETWEEN 1/2 AND 1 INCH OF SLEET. FARTHER NORTHWEST...FROM FORT WORTH TO BOWIE...ACCUMULATIONS OF 1 TO 1 1/2 INCH OF SLEET WITH HEAVIER AMOUNTS WILL BE POSSIBLE. SOME LIGHT FREEZING RAIN WILL ALSO BE POSSIBLE THROUGH MORNING BUT ICE ACCUMULATIONS SHOULD GENERALLY BE LESS THAN 1/10 OF AN INCH. FARTHER SOUTH OF THE METROPLEX...WHERE THE CURRENT ADVISORY IS POSTED...THE WARM NOSE WILL BE A LITTLE MORE STOUT INITIALLY. THIS MAY KEEP PRECIPITATION ALL LIQUID AS OPPOSED TO SLEET. WITH TEMPERATURES FALLING BELOW FREEZING...SOME LIGHT ICING IS EXPECTED. THIS WILL BE WORST ON BRIDGES AND OVERPASSES. MOST OF THE PRECIPITATION SHOULD MOVE EAST OF THE AREA BY LATE MONDAY BUT WE WILL KEEP SOME LOW CHANCES IN THROUGH THE EVENING. SOME LIGHT FREEZING RAIN OR DRIZZLE MAY BE POSSIBLE DURING THIS TIME WITH LITTLE ADDITIONAL IMPACT. TEMPERATURES ON MONDAY ARE NOT EXPECTED TO RISE ABOVE FREEZING SO ANY ACCUMULATIONS OF SLEET/ICE WILL NOT MELT. THIS WILL RESULT IN CONTINUED TRAVEL PROBLEMS. TEMPERATURES ARE EXPECTED TO RISE ABOVE FREEZING BY MIDDAY TUESDAY. LITTLE CHANGES MADE TO THE END OF THE WEEK SYSTEM AS THERE IS STILL CONSIDERABLY MODEL UNCERTAINTY. WE HAVE CONTINUED WITH A RAIN/SNOW MIX LATE THURSDAY INTO LATE FRIDAY ACROSS MUCH OF THE AREA. DUNN && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 26 27 25 39 31 / 80 100 20 20 10 WACO, TX 30 31 24 38 33 / 80 90 30 20 30 PARIS, TX 25 25 25 36 28 / 50 100 30 20 10 DENTON, TX 23 25 20 36 29 / 80 100 10 10 10 MCKINNEY, TX 26 26 23 38 28 / 70 100 20 10 10 DALLAS, TX 28 29 26 39 31 / 80 100 20 20 10 TERRELL, TX 29 29 25 37 30 / 70 100 20 20 10 CORSICANA, TX 30 30 26 38 32 / 70 90 30 20 20 TEMPLE, TX 31 32 25 40 34 / 90 90 30 20 30 MINERAL WELLS, TX 24 25 20 36 28 / 100 100 10 10 10 && .FWD WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR TXZ091>095- 100>107-115>123-129>134-141. WINTER WEATHER ADVISORY UNTIL 6 PM CST MONDAY FOR TXZ135-142>148- 156>162-174-175. && $$ 79/82
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1101 PM CST Sun Feb 22 2015 .AVIATION... /06Z TAFS/ Generally IFR/LIFR conditions are being experienced at all TAF sites late this evening and should continue through Tuesday morning. Areas of light freezing drizzle are also occurring. Freezing rain/sleet is forecast to develop after midnight, mainly affecting KABI and KSJT, then moving east of the area by mid morning Monday. Areas of light freezing drizzle may continue into early afternoon Monday. Northeast winds of 12 to 20 knots, with higher gusts, will diminish to 8 to 12 knots late Monday morning. && .PREV DISCUSSION... /ISSUED 955 PM CST Sun Feb 22 2015/ UPDATE... Based on radar data, it appears we`re in a bit of a lull across the area now. However, calls across the CWA and automated surface observations indicate that widespread, light freezing drizzle is occurring in many areas. Temperatures continue to run a few degrees below even the coldest guidance, with current readings in the 20s everywhere excluding the I-10 corridor (lower 30s). Temperatures will continue to slowly drop tonight, setting the stage for the next shortwave trough. The primary wave looks to be moving across the northern Baja Peninsula at this time, with notable forced ascent downstream over AZ, NM, and northern Mexico. There is a band of frontogenetic forcing sloping up and over the cold dome from north to south that is progged to persist into Monday morning before weakening. This area of mesoscale lift should be enhanced by the approaching shortwave energy. The going forecast looks to be in relatively good shape. The wx grids were modified for this evening, with widespread drizzle and only a chance for sleet mentioned areawide. However, after midnight, we expect additional precipitation to develop. Point soundings suggest the favored precipitation types to be sleet and freezing rain. However, both the NAM and RAP soundings show the cold near surface layer (below the inversion) to be near -10C. While this generally favors supercooled liquid hydrometeors, this is a borderline temperature for the activation of ice nuclei. This would account for the very light snow we`ve had reported over the past few hours. Expect snow accumulations to be a dusting or less. With elevated instability in place, this precipitation should be more convective in nature, with the potential for thundersleet overnight. In areas that do experience thunder, the enhanced convective updrafts may lead to localized higher amounts of sleet and/or snow. Precipitation is expected to diminish by Monday afternoon, although freezing drizzle will remain possible even into Monday evening. Expect surface temperatures on Monday to remain well below freezing, with highs in the mid/upper 20s. There may be just enough radiation coming through the thick overcast to improve road surfaces on Monday, but most of the ice should persist into Tuesday morning. Johnson PREV DISCUSSION... /ISSUED 514 PM CST Sun Feb 22 2015/ AVIATION... /00Z TAFS/ Generally LIFR/IFR conditions are being experienced at all sites this evening and are forecast to continue through the next 24 hours. Light freezing drizzle continues at KABI and is forecast to develop at KSJT around 00z as temperatures drop to or below freezing. Light drizzle will continue at the other sites then transition to light freezing drizzle late this evening as temperatures drop below freezing. Areas of light freezing rain/sleet may develop after midnight, mainly at KABI and KSJT. Northeast winds of 12 to 20 knots, with higher gusts, will decrease to 8 to 12 knots by late morning Monday. PREV DISCUSSION... /ISSUED 409 PM CST Sun Feb 22 2015/ SHORT TERM... (Tonight through Tuesday morning) The much talked about winter storm is beginning to affect the area. Another cold front was crossing the area at 3 PM and was located along an Ozona to just south of Brownwood line, with cold air rapidly invading the area behind this front. Trends in the observations are showing temperatures dropping 5 to 10 degrees per hour behind it. In fact, many areas along/north of Interstate 20 have already dropped below freezing with freezing rain, sleet, and ice accumulations already occurring per social media, phone calls, and observations. Given these developments over the last few hours, and after coordinating with surrounding offices, the Winter Storm Warning start time has been increased to 4 PM this afternoon. Things continue to look like they`ll get messy through tomorrow. The numerical models remain consistent dropping temperatures into the lower to mid 20s across the warned area, and near freezing farther south, with not much recovery tomorrow afternoon. They have also trended stronger/farther south with their convective signature. The Storm Prediction Center has most of West Central Texas in a risk for thunder tonight/tomorrow and model soundings show 100-250 J/kg of MUCAPE across the entire forecast area during this period. As a result, thunder was included in all zones for tonight through mid afternoon tomorrow. LONG TERM... (Tuesday through Sunday) All hands on board for the first winter storm, so this part of the discussion will be brief. Warming trend starts on Tuesday afternoon, although it will be modest. A few breaks in the clouds will allow a little sun, enough to allow temperatures to climb into the 40s. Another upper level low will drop into the southwest US, with return flow ahead of it allowing readings to climb into the 60s on Wednesday. Next arctic front moves across the area for Thursday and Friday, just ahead of the upper level trough moving across. GFS and the ECMWF have some differences in the strength of this system, with the GFS shearing it out a little faster. For now, kept the compromise intact and have slight chance to chance PoPs across the area. Models did warm just a tad, so was able to shift the mention of snow a little farther north. && .PRELIMINARY POINT TEMPS/POPS... Abilene 21 25 20 40 29 / 90 80 10 10 5 San Angelo 25 29 25 46 31 / 90 70 10 10 5 Junction 29 32 28 48 34 / 80 70 10 10 10 && .SJT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING until 6 PM CST Monday FOR THE FOLLOWING ZONES: Brown...Callahan...Coke...Coleman...Concho...Fisher... Haskell...Irion...Jones...Nolan...Runnels...Shackelford... Sterling...Taylor...Throckmorton...Tom Green. WINTER WEATHER ADVISORY until 6 PM CST Monday FOR THE FOLLOWING ZONES: Crockett...Kimble...Mason...McCulloch...Menard...San Saba...Schleicher...Sutton. && $$ Daniels
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1130 PM CST SUN FEB 22 2015 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 231 PM CST SUN FEB 22 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH PRESSURE DRIFTING SOUTHEAST OVER THE NORTHERN GREAT PLAINS EARLY THIS AFTERNOON. THOUGH COLD ADVECTION IS ONGOING...HEATING HAS SERVED TO STEEPEN LOW LEVEL LAPSE RATES...WHICH TRIGGERED A CU FIELD TO FORM LATE IN THE MORNING. DRY AIR IS WINNING OUT THIS AFTERNOON AS EVIDENT BY THE CU FIELD DIMINISHING. ONLY CLEAR AND BITTERLY COLD CONDITIONS EXIST UPSTREAM...SO FORECAST CONCERNS INCLUDE TEMPS AND WIND CHILLS THROUGH MONDAY. TONIGHT...STRONG ARCTIC HIGH PRESSURE WILL BE SLIDING SOUTHEAST FROM THE NORTHERN GREAT PLAINS TO CENTRAL IOWA. LOSS OF DIURNAL HEATING WILL CAUSE ANY LINGERING CU TO DISSIPATE BY EARLY THIS EVENING...WHICH WILL LEAVE CLEAR SKIES FOR MUCH OF THE NIGHT. BECAUSE THE ARCTIC HIGH WILL DROP SOUTHWEST OF THE REGION...BOTH STATISTICAL AND NUMERICAL GUIDANCE POINT TOWARDS WINDS REMAINING IN THE 5 TO 10 KT RANGE THIS EVENING...BEFORE DIMINISHING SOME OVERNIGHT. SOME POTENTIAL FOR DECOUPLING OVER N-C WISCONSIN AS BOUNDARY LAYER WINDS LIGHTEN. AS A RESULT...THINK TEMPERATURES HAVE A CHANCE TO TUMBLE LATE TONIGHT. THIS MAKES FOR A DILEMMA IN TERMS OF HEADLINE DECISIONS. IF WINDS REMAIN IN THE 4-5 KT RANGE...SOME PLACES LIKE ANTIGO AND RHINELANDER COULD REACH WIND CHILL WARNING CRITERIA FOR A PERIOD LATE TONIGHT INTO MONDAY MORNING. THINK WARNING CONDITIONS WILL NOT BE WIDESPREAD ENOUGH DUE TO WINDS DROPPING OFF. SO WILL STICK WITH THE ADVISORY THROUGH THE NIGHT AND CONTINUE TO MENTION THAT SOME SPOTS WILL HIT WARNING CRITERIA. IF WINDS DO DROP OFF...TEMPS 25 TO 30 BELOW ARE POSSIBLE. MONDAY...HIGH PRESSURE WILL BE DRIFTING TO THE MID-MISSISSIPPI VALLEY WHILE THE NEXT CLIPPER WILL REACH NORTHERN MINNESOTA LATE IN THE AFTERNOON. A TIGHTENING PRESSURE GRADIENT BETWEEN THESE FEATURES WILL CAUSE WINDS TO SWING AROUND TO THE SOUTHWEST AND BECOME GUSTY IN THE AFTERNOON. BUT THE SOUTHWEST WINDS WILL ALSO HELP MODERATE THE BITTERLY COLD AIRMASS. WIND CHILLS WILL BE WARMING ABOVE ADVISORY CRITERIA BY LATE IN THE MORNING SO THE ENDING TIME LOOKS ABOUT RIGHT. THOUGH CIRRUS WILL BE INCREASING IN THE AFTERNOON...HIGHS WILL WARM INTO THE UPPER SINGLE DIGITS TO THE LOWER TEENS. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 231 PM CST SUN FEB 22 2015 OVERALL UPPER LEVEL PATTERN CONSISTING OF A WESTERN RIDGE AND EASTERN TROUGH WILL REMAIN FOR MOST OF THE PERIOD...ALTHOUGH THERE ARE HINTS THAT THE WESTERN RIDGE MAY REORGANIZE FURTHER WEST OVER THE PACIFIC WHILE FLOW OVER THE UNITED STATES TAKES ON MORE OF AN APPEARANCE OF SPLIT FLOW. THIS CHANGE DOES NOT LOOK LIKE IT WILL DO MUCH TO REVERSE OUR TREND OF SEEING TEMPS WELL BELOW NORMAL. FOR NOW...ONLY TUESDAY LOOKS TO SEE HIGHS RELATIVELY NEAR NORMAL...WITH A RETURN TO COLD WEATHER AFTER A FRONT MOVES THROUGH. THE PRIMARY CHANCE FOR MEASURABLE SNOW LOOKS TO BE MONDAY NIGHT AND TUESDAY AS A LOW PRESSURE PASSES NORTH THROUGH ONTARIO...WITH AN ATTACHED COLD FRONT PUSHING ACROSS THE AREA ONCE AGAIN. GUIDANCE CONTINUES TO LIKE OUR FAR NORTH FOR THE BEST CHANCE AND AMOUNTS OF SNOW...TO BE EXPECTED AS THE LOW PASSES SOME DISTANCE TO OUR NORTH AND EAST. HOWEVER...THE GFS AND TO SOME EXTENT THE GEM PROVIDE BETTER MOISTURE AND LIFT...AND BRING AN INCH OR TWO OF SNOW DOWN THROUGH A LARGE PORTION OF THE NORTHEAST QUARTER OF WISCONSIN. IT IS WORTH NOTING THAT THE GFS ENSEMBLE CONTINUES TO NOT BE AS ENAMORED OF THIS IDEA AS THE DETERMINISTIC RUN. IN GENERAL WILL FOLLOW SUIT...PUTTING THE HIGHEST POPS AND ACCUMULATIONS IN FAR NORTHERN WISCONSIN...BUT WILL PAY SOME DEFERENCE TO THE NORTH AMERICAN MODELS AND THEIR PLAUSIBLE...IF NOT AS CONVINCING...IDEA OF MORE SNOW FURTHER TO THE SOUTH AND WEST WITH CHANCE POPS TUESDAY MORNING. ALONG WITH THIS SNOW...OUR POSITION BETWEEN THIS ONCOMING LOW AND THE HIGH RESPONSIBLE FOR OUR MOST RECENT COLD PLUNGE WILL RESULT IN GUSTY SOUTHWEST WINDS MONDAY NIGHT INTO TUESDAY. THIS COULD CREATE SOME BLOWING AND DRIFTING OF ANY SNOW THAT MAY FALL...EVEN IF AMOUNTS ARE NOT PARTICULARLY HIGH. GUIDANCE IS UNANIMOUS IN STRONG 50 TO 65 KNOT WINDS AT RELATIVELY LOW ALTITUDE VERY EARLY TUESDAY MORNING. SOUNDINGS IN BUFKIT SHOW POTENTIAL GUSTS TO 20-30 KTS...AND GUSTS EVEN A LITTLE HIGHER ARE NOT OUT OF THE QUESTION...THOUGH THIS SCENARIO WOULD NEED BETTER MIXING TO COME TO FRUITION. AFTERWARDS...HIGH PRESSURE SETTLES OVER THE AREA BRINGING DRY WEATHER THROUGH SATURDAY. IN WHAT SURELY IS BEGINNING TO SOUND ALL TOO FAMILIAR...WE WILL SEE ANOTHER SHOT OF WELL BELOW NORMAL TEMPERATURES. THE COLDEST PERIOD LOOKS TO BE TUESDAY NIGHT THROUGH THURSDAY. HIGHS ON WEDNESDAY LOOK TO BE MIRED IN THE SINGLE DIGITS FOR MOST...WITH SUBZERO LOWS ON TAP TUESDAY AND WEDNESDAY NIGHT. A SLOW MODERATION IN TEMPERATURES IS EXPECTED THROUGH THE WEEKEND. ANOTHER CHANCE FOR PRECIPITATION EMERGES DURING THE WEEKEND...BUT WITH A GOOD BIT OF UNCERTAINTY IN THE NATURE OF THE UPPER FLOW...WILL NOT SPECULATE ON THE DETAILS FOR NOW. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1130 PM CST SUN FEB 22 2015 VFR CONDITIONS TO PREVAIL TNGT THRU MON EVENING AS A LARGE AREA OF HI PRES MOVES FROM THE NRN PLAINS SE TOWARD THE OHIO RIVER VALLEY. WINDS ARE FCST TO SLOWLY BACK FROM W-NW OVRNGT...TO WEST MON MORNING...TO SW MON AFTERNOON. THE PRES GRADIENT WL GRADUALLY TIGHTEN MON AFTERNOON BETWEEN THE HI PRES TO OUR SOUTH AND AN AREA OF LOW PRES RESIDING WELL TO OUR NORTH. WIND GUSTS COULD APPROACH 20 KTS BY LATE MON AFTERNOON AND 25 KTS MON EVENING. NE WI WL ALSO SEE AN INCREASE IN HI CLOUDS MON AFTERNOON WITH MID CLOUDS ARRIVING MON EVENING AHEAD OF A CDFNT THAT IS FCST TO MOVE THRU THE AREA ON TUE. && .GRB WATCHES/WARNINGS/ADVISORIES... WIND CHILL ADVISORY UNTIL 10 AM CST MONDAY FOR WIZ005-010>013- 018>022-030-031-035>040-045-048>050-073-074. && $$ SHORT TERM.....MPC LONG TERM......LUCHS AVIATION.......AK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
329 AM MST MON FEB 23 2015 .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 329 AM MST MON FEB 23 2015 WK SWLY FLOW ALOFT THIS MORNING WILL BECOME LIGHT NNW BY LATE AFTN AND CONTINUE TONIGHT. LINGERING MOISTURE EARLY THIS MORNING MAY ALLOW FOR A FEW AREAS OF VERY LIGHT SNOW IN THE FOOTHILLS AND OVER PORTIONS OF NERN CO THRU 15Z. IN THE MTNS BEST CHC OF SNOW WILL BE ALONG AND SOUTH OF I-70 WHICH MAY LINGER THRU THE AFTN HOURS AS ACTIVITY BECOMES MORE CONVECTIVE DUE TO FAVORABLE LAPSE RATES. AS FOR HIGHS WILL KEEP READINGS MAINLY IN THE 20-25 RANGE ACROSS NERN CO. FOR TONIGHT ANY LINGERING SNOW IN THE MTNS SHOULD END THIS EVENING WITH DRY CONDITIONS ELSEWHERE. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 329 AM MST MON FEB 23 2015 AN ACTIVE AND VERY WINTRY WEATHER PATTERN WILL REMAIN IN PLACE THROUGH THE UPCOMING WEEK. TUESDAY IS SHAPING UP TO BE THE MOST QUIET AND WARMEST DAY OF THE WEEK WITH MOSTLY SUNNY SKIES AND WARM ADVECTION ALOFT. HOWEVER...ABUNDANT SNOW COVER AND LACK OF DOWNSLOPE WILL LIMIT THE AMOUNT OF WARMING. WE SHOULD STILL SEE HIGHS APPROACH 40F OVER SNOW COVERED AREAS OF THE PLAINS...WITH MID/UPPER 40S OVER THE FAR NORTHEAST CORNER WHERE ONLY A LIGHT DUSTING OF SNOW OCCURRED WITH THIS LAST STORM. WEDNESDAY WILL SEE ANOTHER CHANGE. WE SHOULD SEE OROGRAPHIC SNOW DEVELOP ACROSS THE MOUNTAINS AS EARLY AS LATE TUESDAY NIGHT OR WEDNESDAY MORNING AS MOISTURE INCREASES AHEAD OF NEXT FAST MOVING SHORT WAVE. BY LATE MORNING INTO THE AFTERNOON...EXPECT SHOWERS TO SPILL ACROSS THE PLAINS AND INCREASE IN COVERAGE THROUGH THE AFTERNOON HOURS BEHIND COLD FRONTAL PASSAGE. SEEMS MODELS ARE A BIT FASTER WITH THIS COLD FRONT SO SHOULD SEE FALLING TEMPERATURES AND GUSTY NORTH WINDS ACROSS THE PLAINS THROUGH THE AFTERNOON. WITH REGARD TO SNOW POTENTIAL...WE DO EXPECT ACCUMULATING SNOWFALL ACROSS THE MOUNTAINS...FOOTHILLS...AND NEARBY PLAINS INCLUDING THE I-25 URBAN CORRIDOR WHERE UPSLOPE FLOW WILL ACT TO FOCUS PRECIPITATION. UPSLOPE IS EXPECTED TO DEEPEN TO 700 MB OR MORE IN NORTHWEST FLOW ALOFT...AND LAPSE RATES WILL BE NEARLY NEUTRAL THROUGH A DEEP LAYER DURING THE WEDNESDAY AFTERNOON/EARLY EVENING HOURS. Q-G FIELDS ALSO SUPPORT DEEP BUT MODEST LIFT DURING THIS PERIOD. AS A RESULT...CONTINUED TREND OF INCREASING POPS NEAR THE FRONT RANGE...WITH POTENTIAL FOR A FEW INCHES OF ACCUMULATION. THE EASTERN PLAINS WILL ALSO SEE A GOOD CHANCE OF SNOW...BUT LACK OF STRONGER UPSLOPE FORCING WILL LIKELY LIMIT ACCUMULATION POTENTIAL THERE. BY THURSDAY...SOME MODELS ARE POINTING AT ANOTHER BUT WEAKER SHORT WAVE IN NORTHWEST FLOW ALOFT. THIS WILL KEEP A CHANCE OF SOME SNOW IN THE FORECAST...WHILE COLDER AIR ALSO REMAINS FIRMLY ENTRENCHED EAST OF THE ROCKIES. HAVE KEPT A COLD FORECAST IN PLACE WITH TEMPS LIKELY STRUGGLING TO REACH 20F ON THE PLAINS PER LATEST GRIDDED TEMP OUTPUT. AT THIS TIME...FRIDAY INTO SATURDAY APPEAR TO BE MAINLY IN BETWEEN WEATHER SYSTEMS. HOWEVER...HARD TO ELIMINATE SNOW CHANCES WITH SOME MOISTURE IN NORTHWEST FLOW ALOFT FRIDAY...AND POSSIBLE FASTER ARRIVAL OF NEXT STORM SYSTEM BY SATURDAY. TEMPERATURES SHOULD MODERATE DURING THIS TIME FRAME BUT REMAIN A GOOD 15 DEGREES BELOW NORMAL EVEN INTO SATURDAY. FOR LATE SATURDAY INTO SUNDAY...SNOW CHANCES WOULD INCREASE AGAIN AS LATEST MEDIUM RANGE GUIDANCE AND ENSEMBLES SHOW ANOTHER BUT DEEPER TROUGH HEADED INTO THE SOUTHWEST U.S. WILL GO WITH ABOVE CLIMATOLOGY POPS FOR THIS PERIOD GIVEN THE REASONABLE AGREEMENT IN MODEL SOLUTION OF TROUGHINESS/FRONTAL PASSAGES. && .AVIATION...(FOR THE TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 329 AM MST MON FEB 23 2015 THERE COULD BE SOME VERY LIGHT SNOW THRU 15Z HOWEVER NO ACCUMULATIONS ARE EXPECTED. WK DENVER CYCLONE WAS OVER DIA EARLY THIS MORNING AND MAY STAY NR THE AIRPORT THRU MIDDAY. WITH THIS TYPE OF SITUATION ALWAYS HAVE TO BE AWARE OF SOME POTENTIAL FOG/STRATUS HOWEVER HRRR KEEPS IT MAINLY WEST AND SOUTH DIA FOR NOW. WINDS NEAR THE CYCLONE WILL BE VARIABLE AROUND 5KTS THIS MORNING. BY MIDDAY THE WK CYCLONE MAY MOVE TO THE EAST OF NE OF DIA WITH LIGHT NNW WINDS DEVELOPING. FOR TONIGHT WINDS SHOULD BECOME LIGHT DRAINAGE BY EARLY EVENING. VFR CONDITIONS ARE EXPECTED THIS AFTN AND TONIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...RPK LONG TERM...BARJENBRUCH AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
544 AM EST MON FEB 23 2015 .UPDATE...WIDESPREAD DENSE FOG OVER WESTERN FLORIDA PENINSULA IS SLOWLY ADVECTING EASTWARD AND MOVING INTO LAKE COUNTY EARLY THIS MORNING BASED ON LATEST SATELLITE AND SFC OBS. NOT QUITE SURE HOW FAR EASTWARD THIS MORE WIDESPREAD FOG WILL BE ABLE TO TRAVEL BEFORE DAYTIME HEATING BEGINS TO SET IN THIS MORNING. FOR NOW HAVE JUST DECIDED TO ISSUE A DENSE FOG ADVISORY FOR LAKE COUNTY...BUT WILL CONTINUE TO MONITOR FOR ANY ADDITIONAL EXPANSION. && .PREV DISCUSSION... /ISSUED 348 AM EST MON FEB 23 2015/ DISCUSSION... TODAY/TONIGHT...COLD FRONT CURRENTLY JUST NORTH OF FL WILL WEAKEN AS IT SHIFTS SWEETHEART AND EVENTUALLY INTO THE AREA TONIGHT. ANY FOG/STRATUS INITIALLY OVER THE REGION WILL BURN OFF BY LATE MORN WITH PARTLY CLOUDY SKIES EXPECTED THROUGH MUCH OF THE DAY. TEMPS WILL REMAIN ABOVE NORMAL WITH HIGHS RANGING FROM THE UPPER 70S OVER LAKE AND VOLUSIA COUNTY TO LOW 80S FARTHER SOUTH. MODELS SHOW A LITTLE HIGHER MOISTURE WORKING INTO NRN AREAS LATER IN THE AFT AHEAD OF THE FRONT WHICH MAY LEAD TO A FEW SHRAS...SO HAVE INCLUDED SLIGHT CHANCE POPS NORTH OF ORLANDO. THE LATEST HRRR INDICATES SOME ISO SHRA ACTIVITY EVEN FARTHER SOUTH BY LATE DAY BUT LOW LEVEL MOISTURE IS FAIRLY SHALLOW AND MOS POPS REMAIN BELOW MENTIONABLE LEVELS SO WILL KEEP RAIN CHANCES OUT OF THE FORECAST ELSEWHERE. AS FRONT MOVES INTO CENTRAL FLORIDA TONIGHT RAIN CHANCES WILL CONTINUE TO INCREASE SLIGHTLY MAINLY OVER NORTHERN PORTIONS OF THE AREA. ALSO CLOUD COVER WILL INCREASE AS LOW CLOUD DECK BUILDS IN BEHIND THE BOUNDARY. SINCE FRONT WILL BE WEAK...OVERNIGHT TEMPS WILL STAY ABOVE NORMAL WITH LOWS IN THE UPPER 50S TO LOW 60S. TUE...WEAK COLD FRONT SHOULD SHIFT TO THE SOUTHERN SECTIONS. FORECAST SOUNDINGS SHOW A SHALLOW COOL AIR MASS WITH CONSIDERABLE LOW CLOUDINESS ESPECIALLY ACROSS THE NORTH HALF. ISENTROPIC LIFT WILL BE SHALLOW/WEAK SO EXPECT ONLY SCATTERED LIGHT PRECIP. MAX TEMPS WILL BE KNOCKED DOWN CONSIDERABLY ACROSS THE NORTH WITH THE CLOUD COVER AND NORTHERLY WIND FLOW. SOUTHERN SECTIONS WILL HAVE A LITTLE MORE CLOUDINESS DEVELOPING IN THE AFTERNOON BUT MAX TEMPS SHOULD STILL BE 80 AROUND OKEECHOBEE. TUE NIGHT...A WEAK LOW EAST OF THE COASTAL WATERS IS FORECAST TO PULL AWAY TO THE NORTHEAST BUT THE WEAK/SHALLOW FRONTAL BOUNDARY SHOULD CONTINUE TO EXTEND ACROSS THE SOUTHERN PENINSULA. MOS POPS ARE 20-30 PERCENT...BUT THE MAIN CONCERN MAY ACTUALLY TURN OUT TO BE LOW STRATUS/FOG. WILL NOT MENTION YET AND KEEP POPS AT 20 PERCENT OR LESS. WED-THU...THE 00Z GFS/ECMWF HAVE COME INTO GOOD AGREEMENT DURING THIS PERIOD. THE MAIN FEATURE WILL BE A SOUTHERN STREAM SHORTWAVE TROUGH THAT MOVES ACROSS THE DEEP SOUTH WED WHILE GRADUALLY DAMPENING OUT. THE ACCOMPANYING SURFACE LOW IS FORECAST TO PUSH INTO NORTH FLORIDA WED AFTERNOON AND SHIFT TO OFFSHORE THE CAROLINAS BY 12Z THU. THE WARM SECTOR WILL ENCOMPASS THE LOCAL AREA AS LOW LEVEL WINDS BECOME SOUTHERLY AND INCREASE WED INTO WED NIGHT. THE MODELS SHOW MAIN PRECIP OCCURRING NEAR A WARM FRONT TO OUR NORTH ON WED THEN AS COLD FRONT DROPS TOWARDS THE AREA OVERNIGHT...A BAND OF CONVECTION WILL ACCOMPANY IT. THE BAND OF CONVECTION SHOULD SHIFT INTO SOUTHERN SECTIONS ON THU. HAVE NOT MADE MUCH CHANGE TO THE PREVIOUS FORECAST WHICH HAS CHANCE POPS NORTH AND SLIGHT CHANCE IN THE SOUTH WED AND WED NIGHT...EXCEPT BECOMING LIKELY IN THE NORTH WED NIGHT. CHANCE POPS SHOULD BE A LITTLE HIGHER IN THE SOUTH ON THU. WITH QUITE STRONG LOW LEVEL WINDS AS SURFACE LOW MOVES BY JUST TO OUR NORTH...THE MENTION OF ISOLATED STORMS LOOKS GOOD WED NIGHT ESPECIALLY NORTH HALF...WITH A SLIGHT CHANCE THAT STORMS COULD BE STRONG. FRI-NEXT MON...LARGE HIGH PRESSURE CENTERED OVER THE MID PART OF THE COUNTRY SHOULD PUSH FRONTAL BOUNDARY INTO THE NORTHERN BAHAMAS ON FRI BUT THE MODELS SHOW FRONT HANGING UP AND THE ASSOCIATED MOISTURE FROM IT LIFTING BACK NORTH. THIS WILL ALLOW A MENTION OF SLIGHT CHANCE TO CHANCE POPS THROUGH THE WEEKEND. TEMPERATURES GENERALLY EXPECTED TO STAY NEAR TO JUST BELOW SEASONAL NORMS FRI THEN MODERATE SAT AS BREEZY ONSHORE FLOW DEVELOPS...THEN BE ABOVE NORMAL BY SUN AS BREEZY ONSHORE CONTINUES. A DEEP LAYER HIGH PRESSURE RIDGE IS INDICATED OVER THE AREA NEXT MON...SO A WARM AND DRY DAY LOOKS TO BE ON TAP. && AVIATION...PATCHY/AREAS OF FOG THROUGH EARLY MORNING WILL PRODUCE TEMPO IFR/MVFR CONDS THROUGH 13-14Z. ANY FOG SHOULD THEN BURN OFF WITH VFR CONDS EXPECTED INTO THE AFT. WEAK FRONT MOVING INTO THE REGION TONIGHT WILL USHER IN A LOWER CLOUD DECK WITH IFR/LIFR CIGS BUILDING SOUTHWARD OVER THE REGION AS PER LATEST MOS GUIDANCE. SOME PATCHY FOG MAY ALSO BE POSSIBLE BUT AT THIS TIME NOT EXPECTING WIDESPREAD LOWER VISIBILITIES. RAIN CHANCES WILL INCREASE SLIGHTLY INTO LATE DAY AND TONIGHT WITH THE FRONT BUT POPS ARE LOW ENOUGH TO KEEP MENTION OUT OF THE TAFS FOR NOW. && MARINE... TODAY/TONIGHT...LIGHT TO GENTLE BREEZE EXPECTED TODAY OVER THE WATERS WITH WINDS INITIALLY OUT OF THE W/SW BECOMING MORE NORTHERLY AND INCREASING INTO TONIGHT AS A WEAK FRONT MOVES THROUGH THE REGION. NORTHERLY SURGE DOES NOT APPEAR AS STRONG AS IT HAD IN PREVIOUS MODEL RUNS WITH WIND SPEEDS GENERALLY AROUND 15 KNOTS. SEAS BUILDING TO 6 FEET OVER THE OFFSHORE WATERS NORTH OF THE CAPE BY LATE TONIGHT STILL LOOKS REASONABLE...SO WILL MAINTAIN THESE WAVE HEIGHTS IN THE FORECAST. TUE-FRI...A VERY PROGRESSIVE WEATHER PATTERN WILL LEAD TO QUICKLY CHANGING WIND FIELDS THROUGH THE PERIOD. A WEAK LOW IS FORECAST JUST EAST OF THE WATERS TUE WHICH SHOULD PRODUCE A BRIEF PERIOD OF NORTHERLY WINDS 15-20 KNOTS. THEN ON WED...THE WINDS SHOULD START OFF LIGHT AND BECOME SOUTHERLY WHILE INCREASING...AS A SURFACE LOW MOVES TOWARDS NORTH FLORIDA. THE LOW WILL LIFT QUICKLY NORTHEAST AND SWING A COLD FRONT INTO THE WATERS THU. IN ADDITION TO INCREASED RAIN CHANCES WED NIGHT AND THU...BREEZY SOUTHERLY FLOW WILL BECOME NORTHERLY BEHIND THE FRONT THU NIGHT AND CONTINUE INTO FRI. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NORTHERN LAKE COUNTY-SOUTHERN LAKE COUNTY. AM...NONE. && $$ UPDATE/SHORT TERM...WEITLICH LONG TERM....LASCODY
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
636 AM EST MON FEB 23 2015 .SYNOPSIS... A COLD FRONT WILL PUSH ACROSS THE REGION TODAY AND BECOME STATIONARY SOUTH OF THE AREA TONIGHT. DEVELOPING LOW PRESSURE WILL TRACK ALONG THE STATIONARY FRONT OVER THE ATLANTIC TUESDAY. HIGH PRESSURE WILL BRIEFLY BUILD IN TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED BY STRONGER LOW PRESSURE FROM THE GULF OF MEXICO THAT PASSES OFFSHORE WEDNESDAY NIGHT. STRONG HIGH PRESSURE CENTERED NORTH OF THE AREA WILL EXPAND TO BECOME THE PRIMARY FEATURE LATE WEEK INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... TODAY...SHORTWAVE ENERGY EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT IS HELPING PROVIDE SOME UPPER SUPPORT FOR LOW LEVEL FORCING ALONG A COLD FRONT THAT STRETCHES FROM EASTERN NORTH CAROLINA BACK TO THE LOWER MISSISSIPPI VALLEY. THE RESULT IS A LARGE BAND OF WIDESPREAD RAINFALL THAT IS IMPACTING MUCH OF THE NORTHERN HALF OF THE FORECAST AREA THIS MORNING. POPS THROUGH THE REMAINDER OF THE MORNING FEATURE 100 POPS TO THE NORTH...RANGING TO SLIGHT CHANCES FAR TO THE SOUTH AROUND MCINTOSH COUNTY. THE BEST FORCING WILL REMAIN FOCUSED TO THE NORTH AND THAT IS WHERE THE HEAVIEST RAIN WILL FALL. THEN FOLLOWING THE RECENT RUNS OF THE HRRR AND THE RAP...THE BULK OF THE PRECIPITATION WILL COME TO AN END FROM WEST TO EAST IN THE LATE MORNING TO EARLY AFTERNOON HOURS. TEMPERATURES ARE CURRENTLY QUITE MILD ACROSS THE REGION...MAINLY IN THE UPPER 50S AND LOW 60S. THESE VALUES WILL REMAIN STEADY THROUGH DAYBREAK...AND ONLY BEGIN TO FALL WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT. BASED ON THE TIMING IN THE HRRR AND RAP...THE WIND SHIFT AND ASSOCIATED INFILTRATION OF COOLER AIR WILL BEGIN TAKING PLACE AROUND 13Z OR SO. HIGH TEMPERATURES FOR THE DAY WILL OCCUR JUST BEFORE THE FRONT BEGINS ITS SOUTHWARD MARCH...WITH MID 50S IN MOST AREAS AND EVEN SOME UPPER 50S AND LOW 60S POSSIBLE FOR SOUTHEAST GEORGIA. TEMPERATURES WILL THEN STEADILY FALL THROUGH THE DAY. TONIGHT...THE COLD FRONT WILL BECOME NEARLY STATIONARY TO THE SOUTH AND SOUTHEAST OF THE REGION AS HIGH PRESSURE BEGINS TO BRIDGE ACROSS THE OHIO VALLEY AND INTO THE MID ATLANTIC. BY LATE TONIGHT...THE HIGH WILL SETTLE INTO COLD AIR DAMMING POSITION WITH INCREASINGLY COOL AIR OOZING IN FROM THE NORTHEAST. EARLY IN THE TONIGHT PERIOD...THE MODELS GENERALLY SHOW A PRECIPITATION LULL PERIOD AS THE FORCING ALONG THE FRONT IS DISPLACED TO THE SOUTH AND SOUTHEAST AND THE UPPER SUPPORT WANES. HOWEVER...BY VERY LATE TONIGHT THE NOSE OF A 80-90 KT 500 MB JET PUSHES IN FROM THE EAST COINCIDENT WITH AN AREA OF SHALLOW LOW LEVEL ISENTROPIC LIFT. SOME OF THE MODELS SHOW PRECIPITATION BREAKING OUT CLOSER TO SUNRISE AT THE SAME TIME AS SUB FREEZING AIR FILTERS IN FROM THE NORTHEAST. SOUNDINGS SHOW THAT WHATEVER PRECIPITATION DOES FALL WILL LIKELY FALL AS FREEZING RAIN/DRIZZLE AND THROUGH THE VERY LATE TONIGHT PERIOD WILL MAINLY IMPACT THE EXTREME NORTH...ALONG AND NEAR THE SANTEE RIVER. THE BULK OF THIS EVENT WILL THEN OCCUR INTO TUESDAY MORNING. BY LATE TONIGHT...LOWS WILL REACH THE LOW 30S FOR MUCH OF SOUTHEAST SOUTH CAROLINA WITH MID TO UPPER 30S IN SOUTHEAST GEORGIA. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... TUESDAY...THE STALLED OUT FRONT AND ITS ASSOCIATED BAROCLINIC ZONE WILL BE FOUND NOT FAR OFF THE SE COAST. CHANNELED VORTICITY ARRIVING IN THE FAST MOVING AND BROADLY CYCLONIC FLOW ALOFT WILL TRIGGER CYCLOGENESIS A COUPLE HUNDRED MILES OFF THE NE FLORIDA COAST. AT THE SAME TIME...UPPER DIVERGENCE/DIFLUENCE ASSOCIATED WITH THE EXIT REGION OF A ROBUST 130 KT JET AND ISENTROPIC ASCENT ON MAINLY THE 280K AND 285K SURFACES /AROUND 1500-2500 FT/ WILL COMBINE WITH PRODUCE AN EXPANDING AREA OF RAIN ACROSS THE FORECAST AREA. THERE STILL REMAINS SOME DISPARITIES BETWEEN THE VARIOUS MODEL GUIDANCE...BUT WE HAVE LEANED TOWARD A SOLUTION MOST SIMILAR TO A BLEND OF THE NAM...ECMWF AND CANADIAN MODELS AS OPPOSED TO THE GFS. COLDER AIR WILL BE FILTERING INTO THE REGION AS A TRANSIENT HIGH PRESSURE WEDGE DEVELOPS BEHIND THE COLD FRONT STALLED OFFSHORE. THIS WILL CAUSE A CONCERN FOR THE POTENTIAL FOR FREEZING RAIN AND DRIZZLE OVER SEVERAL PARTS OF THE FORECAST AREA. SOUNDING DATA REVEALS THAT THE BEST CHANCE FOR FREEZING SURFACE TEMPS AND/OR WET BULBS WILL OCCUR MAINLY INLAND FROM US-17 IN SC AND OVER JENKINS AND SCREVEN COUNTIES IN SE GA. THIS INCLUDES PARTS OF THE CHARLESTON AND BEAUFORT METRO AREAS...AND IT IS IN THESE LOCATIONS WHERE WE HAVE GONE AHEAD WITH A FREEZING RAIN ADVISORY FROM 4 AM UNTIL 2 PM TUESDAY. WHILE IT IS CERTAINLY COLD ENOUGH FOR ICE/SNOW ALOFT...THERE IS A PRONOUNCED WARM NOSE AROUND 900-750 MB WHICH WILL TURN WILL ALLOW FOR MELTING OF THE FROZEN PRECIP. BUT THERE IS ENOUGH MOISTURE AND COLDER AIR BELOW TO ALLOW FOR THE LIQUID DROPS TO REFREEZE. THERE CAN CERTAINLY BE SOME SLEET MIXED IN...BUT THE BULK OF THE PRECIP LOOKS TO BE FREEZING RAIN AND/OR DRIZZLE. OUR CONFIDENCE ON THE AMOUNT OF ICING IS MODERATE AT BEST...SINCE WE HAVE HAD A SHORT DURATION WARM SPELL AND MUCH OF THE PRECIP MAY TURN OUT BE RATHER LIGHT IN INTENSITY. THAT SAID...WE DO ANTICIPATE A FEW HUNDREDTHS OF AN INCH OF FREEZING RAIN ON VARIOUS SURFACES. KEEP IN MIND THAT THE TALLER BRIDGES OF THE AREA CAN FREEZE BEFORE ROAD SURFACES. THE DON HOLT BRIDGE IN THE CHARLESTON AREA PROBABLY HAS THE BEST CHANCE OF EXPERIENCING ANY ICING PROBLEMS TUESDAY MORNING...BUT WE CAN/T ENTIRELY DISCOUNT THE RAVENEL AND WANDO BRIDGES ALSO GETTING SOME ICE ON THEM. DEPENDING UPON THE INTENSITY OF THE PRECIP WE MAY NEED TO EXPAND THE ADVISORY A LITTLE FURTHER SOUTH INTO GEORGIA AT A LATER TIME. TEMPS LOOK TO BE ABOVE FREEZING IN THE EARLY TO MID AFTERNOON...THUS ANY FREEZING PRECIP WILL CHANGE OVER TO LIQUID BEFORE TAPERING OFF LATE. FOR NOW WE BELIEVE THAT THE PRECIP OVER MUCH OF SE GA...ESPECIALLY TO THE SOUTH OF I-16 WILL BE ALL OR MAINLY LIQUID WITH QPF/S OF 1/10 TO 1/4 INCH TO OCCUR. TEMPS WON/T GO MUCH OF ANYWHERE...EVEN DROPPING A COUPLE OF DEGREES DUE TO THE PRECIP...AND WE/LL BE MAINLY IN THE LOWER AND MIDDLE 30S NORTH/NW TO THE LOWER 40S SOUTH. TUESDAY NIGHT...THE SURFACE WAVE OVER THE ATLANTIC AND THE ASSOCIATED FORCING PULL AWAY AS A MESO-HIGH BUILDS FROM THE WEST. THIS WILL TEMPORARILY SHUT OFF THE PRECIP...AND WE WILL NEED TO WATCH FOR POSSIBLE RE-FREEZING OF THE EARLIER RAINS...ESPECIALLY OVER THE CHARLESTON QUAD-COUNTY DISTRICT. WEDNESDAY AND WEDNESDAY NIGHT...A POTENT SHORT WAVE IN THE DESERT SW TODAY WILL SHIFT THROUGH THE SOUTHERN PLAINS WEDNESDAY AND HEADS INTO THE SE AT NIGHT. THIS TRIGGERS SURFACE CYCLOGENESIS IN THE NORTHERN GULF OF MEXICO BEFORE THE LOW TRACKS JUST OFF THE LOCAL COASTS BY LATE IN THE PERIOD. LARGE SCALE FORCING FROM THESE FEATURES AND A POWERFUL WEST-EAST 150 KT UPPER JET WILL ALLOW FOR CONSIDERABLE OVER-RUNNING RAINS TO DEVELOP BY WEDNESDAY AFTERNOON...BEFORE TAPERING OFF FROM WEST/SW TO EAST/NE LATE WEDNESDAY NIGHT. THIS PROMISES TO BE A PRETTY GOOD SOAKER...WITH PWATS OF 1-1.5 INCHES TO PREVAIL. SOME PLACES COULD EASILY ACHIEVE THESE AMOUNTS GIVEN THAT WE ARE CARRYING CATEGORICAL POPS. RIGHT NOW IT LOOKS TO BE ALL LIQUID UNLESS THE OVER-RUNNING RAINS ARRIVE EARLIER THAN EXPECTED. TEMPS WILL REMAIN FAR BELOW NORMAL. THURSDAY...MUCH DRIER AIR OVERSPREADS THE REGION BEHIND THE EXITING SHORT AVE AND SURFACE LOW...LEADING TO A DRY BUT CHILLY DAY WITH TEMPS AGAIN FAR BELOW SEASONAL NORMS. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A HUMONGOUS AND ROBUST 1040 MB CANADIAN HIGH BUILDING OUT OF THE GREAT PLAINS WILL EXPAND EAST AND SOUTH AND COVERS MUCH OF THE NATION EAST OF THE ROCKIES...INCLUDING THE LOCAL AREA. THIS LEADS TO DRY AND CHILLY CONDITIONS INTO FRIDAY...BEFORE THE HIGH SHIFTS INTO THE ATLANTIC OVER THE WEEKEND AND EARLY NEXT WEEK AND TEMPS BEGIN TO MODERATE. A COASTAL TROUGH WILL LIKELY FORM DURING THIS TRANSITION JUST OFF OUR COAST...AND WE LOOK FOR AT LEAST A SMALL CHANCE OF SHOWERS IN RESPONSE. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... KCHS...MVFR OR LOWER CONDITIONS WILL PREVAIL THROUGH 12Z TUESDAY. LOOKING AT NEARBY OBSERVATIONAL SITES THERE WILL EVEN BE PERIODS OF IFR OR LOWER WEATHER INTO THIS AFTERNOON. MEANWHILE...A SHORT WAVE WILL BRUSH THE TERMINAL DURING THE MID MORNING INTO THIS AFTERNOON...BRINGING WITH IT LIGHT TO PERHAPS RAIN. ALTHOUGH WE CAN/T RULE OUT A LITTLE DRIZZLE LATE THIS AFTERNOON INTO TONIGHT...A GREATER RISK FOR DRIZZLE WILL OCCUR CLOSER TO DAYBREAK TUESDAY. IF IT/S COLD ENOUGH IT MIGHT EVEN BE FREEZING DRIZZLE. LIGHT WINDS THIS MORNING WILL VEER AROUND TO THE NORTH AND INCREASE IN WAKE OF A COLD FRONT AROUND 17Z...REMAINING GUSTY THROUGH THE BALANCE OF THE TAF CYCLE. KSAV...VFR CONDITIONS THIS MORNING WILL BE SHORT-LIVED AS LOWER CLOUD DECKS ARRIVE FROM THE NORTH IN RESPONSE TO AN APPROACHING COLD FRONT. THE FRONT WILL BE ACCOMPANIED BY A LITTLE LIGHT RAIN...BUT A MORE NOTICEABLE CHANGE WILL BE WINDS BECOMING NORTH/NE AND GUSTY INTO TONIGHT WITH SUB-VFR WEATHER TO AGAIN PREVAIL. COULD SEE SOME LIGHT RAINS LATE IN THE PERIOD...BUT A BETTER CHANCE AFTER 12Z TUESDAY. EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS OF VARYING CATEGORIES WILL CONTINUE MUCH OF THE TIME TUESDAY INTO THURSDAY...ALTHOUGH INTERLUDES OF VFR ARE POSSIBLE BETWEEN RAIN EVENTS. ALSO OF NOTE...THERE IS A GOOD CHANCE FOR FREEZING/FROZEN PRECIPITATION TUESDAY MORNING...ESPECIALLY AT KCHS. && .MARINE... EARLY MORNING UPDATE...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR THE CHARLESTON HARBOR AND THE CHARLESTON COUNTY WATERS. THE CHARLESTON HARBOR PILOT BOAT REPORTED NEAR ZERO VISIBILITY RECENTLY AND WEB CAMS AROUND DOWNTOWN AND THE HARBOR SHOW A SHALLOW BANK OF FOG ACROSS THE AREA. THE EXPECTATION IS THAT THERE IS ALSO DENSE FOG JUST OFFSHORE TOO...THUS THE ADVISORY IS IN EFFECT. THE FOG SHOULD START TO MIX OUT AND DISSIPATE IN THE LATE MORNING HOURS/AROUND NOON AS THE COLD FRONT MOVES IN...WINDS PICK UP AND SHIFT AROUND TO NORTH. TODAY AND TONIGHT...A COLD FRONT WILL SINK SOUTHWARD ACROSS THE REGION AND IS EXPECTED TO PUSH ACROSS THE WATERS MAINLY IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...A SIGNIFICANT NORTH TO NORTHEAST SURGE IS EXPECTED TO BEGIN WITH RAPIDLY INCREASING WINDS AND SEAS. WINDS WILL INCREASE FIRST ACROSS THE CHARLESTON COUNTY WATERS AND THE CHARLESTON HARBOR IN THE EARLY AFTERNOON...REACHING THE GEORGIA WATERS IN THE LATE AFTERNOON AND EARLY EVENING HOURS. THE NEARSHORE WATERS WILL SEE WINDS INCREASE INTO THE 20 TO 25 KT RANGE...INCLUDING THE CHARLESTON HARBOR...WITH GUSTS TO 30 KT POSSIBLE FOR THE OUTER GEORGIA WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL WATERS THROUGH THE OVERNIGHT. THE NORTH TO NORTHEAST SURGE WILL CONTINUE TONIGHT IN THE WAKE OF THE FRONT AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE WATERS. WINDS WILL LIKELY REACH THEIR PEAK IN THE MID TO LATE EVENING HOURS WITH GUSTS TO 30 KT POSSIBLE ACROSS ALL WATERS. SEAS WILL CONTINUE TO INCREASE REACHING 4-6 FT WITHIN 20 NM AND 6-9 FT OUT TO 60 NM. TUESDAY...ONGOING SMALL CRAFT ADVISORIES WILL CONTINUE INTO THE AFTERNOON IN ASSOCIATION WITH THE GRADIENT BETWEEN THE ATLANTIC LOW AND A WEAK INLAND HIGH PRESSURE WEDGE. WHILE WE CAN/T RULE OUT A LITTLE FREEZING RAIN IN CHARLESTON HARBOR...THE BULK OF THE WET WEATHER LOOKS TO BE IN THE FORM OF LIQUID. TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS WILL IMPROVE AS THE ATLANTIC LOW PULLS AWAY AND ANOTHER AREA OF HIGH PRESSURE ARRIVES FROM THE WEST. WINDS AND SEAS WILL BE FAR BELOW ANY ADVISORY THRESHOLDS. LATE WEDNESDAY INTO THURSDAY...CONDITIONS AGAIN WILL DETERIORATE AS INTENSIFYING LOW PRESSURE DEVELOPS IN THE GULF OF MEXICO AND TRACKS OVER OR NEAR THE LOCAL WATERS LATE WEDNESDAY NIGHT/EARLY THURSDAY...BEFORE PULLING AWAY THURSDAY AFTERNOON. SMALL CRAFT ADVISORIES ARE AGAIN LIKELY AS A RESULT. FRIDAY THROUGH SATURDAY...A STRENGTHENING REGION OF CONTINENTAL HIGH PRESSURE WILL OVERSPREAD THE REGION AND GIVEN COLD ADVECTION AND A TIGHTENING OF THE PRESSURE GRADIENT ADDITIONAL SMALL CRAFT ADVISORIES ARE ANTICIPATED. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR GAZ087-088. SC...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR SCZ040-042>045-047>050-052. MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST TUESDAY FOR AMZ352. DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ330-350. SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST TUESDAY FOR AMZ350. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 PM EST TUESDAY FOR AMZ354. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EST TUESDAY FOR AMZ374. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 PM EST TUESDAY FOR AMZ330. && $$ SYNOPSIS... NEAR TERM...BSH SHORT TERM... LONG TERM... AVIATION... MARINE...BSH
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
548 AM EST MON FEB 23 2015 .SYNOPSIS... A COLD FRONT WILL PUSH ACROSS THE REGION TODAY AND BECOME STATIONARY SOUTH OF THE AREA TONIGHT. DEVELOPING LOW PRESSURE WILL TRACK ALONG THE STATIONARY FRONT OVER THE ATLANTIC TUESDAY. HIGH PRESSURE WILL BRIEFLY BUILD IN TUESDAY NIGHT INTO EARLY WEDNESDAY...FOLLOWED BY STRONGER LOW PRESSURE FROM THE GULF OF MEXICO THAT PASSES OFFSHORE WEDNESDAY NIGHT. STRONG HIGH PRESSURE CENTERED NORTH OF THE AREA WILL EXPAND TO BECOME THE PRIMARY FEATURE LATE WEEK INTO NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... TODAY...SHORTWAVE ENERGY EMBEDDED WITHIN THE NEARLY ZONAL FLOW ALOFT IS HELPING PROVIDE SOME UPPER SUPPORT FOR LOW LEVEL FORCING ALONG A COLD FRONT THAT STRETCHES FROM EASTERN NORTH CAROLINA BACK TO THE LOWER MISSISSIPPI VALLEY. THE RESULT IS A LARGE BAND OF WIDESPREAD RAINFALL THAT IS IMPACTING MUCH OF THE NORTHERN HALF OF THE FORECAST AREA THIS MORNING. POPS THROUGH THE REMAINDER OF THE MORNING FEATURE 100 POPS TO THE NORTH...RANGING TO SLIGHT CHANCES FAR TO THE SOUTH AROUND MCINTOSH COUNTY. THE BEST FORCING WILL REMAIN FOCUSED TO THE NORTH AND THAT IS WHERE THE HEAVIEST RAIN WILL FALL. THEN FOLLOWING THE RECENT RUNS OF THE HRRR AND THE RAP...THE BULK OF THE PRECIPITATION WILL COME TO AN END FROM WEST TO EAST IN THE LATE MORNING TO EARLY AFTERNOON HOURS. TEMPERATURES ARE CURRENTLY QUITE MILD ACROSS THE REGION...MAINLY IN THE UPPER 50S AND LOW 60S. THESE VALUES WILL REMAIN STEADY THROUGH DAYBREAK...AND ONLY BEGIN TO FALL WITH THE SOUTHWARD PROGRESSION OF THE COLD FRONT. BASED ON THE TIMING IN THE HRRR AND RAP...THE WIND SHIFT AND ASSOCIATED INFILTRATION OF COOLER AIR WILL BEGIN TAKING PLACE AROUND 13Z OR SO. HIGH TEMPERATURES FOR THE DAY WILL OCCUR JUST BEFORE THE FRONT BEGINS ITS SOUTHWARD MARCH...WITH MID 50S IN MOST AREAS AND EVEN SOME UPPER 50S AND LOW 60S POSSIBLE FOR SOUTHEAST GEORGIA. TEMPERATURES WILL THEN STEADILY FALL THROUGH THE DAY. TONIGHT...THE COLD FRONT WILL BECOME NEARLY STATIONARY TO THE SOUTH AND SOUTHEAST OF THE REGION AS HIGH PRESSURE BEGINS TO BRIDGE ACROSS THE OHIO VALLEY AND INTO THE MID ATLANTIC. BY LATE TONIGHT...THE HIGH WILL SETTLE INTO COLD AIR DAMMING POSITION WITH INCREASINGLY COOL AIR OOZING IN FROM THE NORTHEAST. EARLY IN THE TONIGHT PERIOD...THE MODELS GENERALLY SHOW A PRECIPITATION LULL PERIOD AS THE FORCING ALONG THE FRONT IS DISPLACED TO THE SOUTH AND SOUTHEAST AND THE UPPER SUPPORT WANES. HOWEVER...BY VERY LATE TONIGHT THE NOSE OF A 80-90 KT 500 MB JET PUSHES IN FROM THE EAST COINCIDENT WITH AN AREA OF SHALLOW LOW LEVEL ISENTROPIC LIFT. SOME OF THE MODELS SHOW PRECIPITATION BREAKING OUT CLOSER TO SUNRISE AT THE SAME TIME AS SUB FREEZING AIR FILTERS IN FROM THE NORTHEAST. SOUNDINGS SHOW THAT WHATEVER PRECIPITATION DOES FALL WILL LIKELY FALL AS FREEZING RAIN/DRIZZLE AND THROUGH THE VERY LATE TONIGHT PERIOD WILL MAINLY IMPACT THE EXTREME NORTH...ALONG AND NEAR THE SANTEE RIVER. THE BULK OF THIS EVENT WILL THEN OCCUR INTO TUESDAY MORNING. BY LATE TONIGHT...LOWS WILL REACH THE LOW 30S FOR MUCH OF SOUTHEAST SOUTH CAROLINA WITH MID TO UPPER 30S IN SOUTHEAST GEORGIA. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... TUESDAY...THE STALLED OUT FRONT AND ITS ASSOCIATED BAROCLINIC ZONE WILL BE FOUND NOT FAR OFF THE SE COAST. CHANNELED VORTICITY ARRIVING IN THE FAST MOVING AND BROADLY CYCLONIC FLOW ALOFT WILL TRIGGER CYCLOGENESIS A COUPLE HUNDRED MILES OFF THE NE FLORIDA COAST. AT THE SAME TIME...UPPER DIVERGENCE/DIFLUENCE ASSOCIATED WITH THE EXIT REGION OF A ROBUST 130 KT JET AND ISENTROPIC ASCENT ON MAINLY THE 280K AND 285K SURFACES /AROUND 1500-2500 FT/ WILL COMBINE WITH PRODUCE AN EXPANDING AREA OF RAIN ACROSS THE FORECAST AREA. THERE STILL REMAINS SOME DISPARITIES BETWEEN THE VARIOUS MODEL GUIDANCE...BUT WE HAVE LEANED TOWARD A SOLUTION MOST SIMILAR TO A BLEND OF THE NAM...ECMWF AND CANADIAN MODELS AS OPPOSED TO THE GFS. COLDER AIR WILL BE FILTERING INTO THE REGION AS A TRANSIENT HIGH PRESSURE WEDGE DEVELOPS BEHIND THE COLD FRONT STALLED OFFSHORE. THIS WILL CAUSE A CONCERN FOR THE POTENTIAL FOR FREEZING RAIN AND DRIZZLE OVER SEVERAL PARTS OF THE FORECAST AREA. SOUNDING DATA REVEALS THAT THE BEST CHANCE FOR FREEZING SURFACE TEMPS AND/OR WET BULBS WILL OCCUR MAINLY INLAND FROM US-17 IN SC AND OVER JENKINS AND SCREVEN COUNTIES IN SE GA. THIS INCLUDES PARTS OF THE CHARLESTON AND BEAUFORT METRO AREAS...AND IT IS IN THESE LOCATIONS WHERE WE HAVE GONE AHEAD WITH A FREEZING RAIN ADVISORY FROM 4 AM UNTIL 2 PM TUESDAY. WHILE IT IS CERTAINLY COLD ENOUGH FOR ICE/SNOW ALOFT...THERE IS A PRONOUNCED WARM NOSE AROUND 900-750 MB WHICH WILL TURN WILL ALLOW FOR MELTING OF THE FROZEN PRECIP. BUT THERE IS ENOUGH MOISTURE AND COLDER AIR BELOW TO ALLOW FOR THE LIQUID DROPS TO REFREEZE. THERE CAN CERTAINLY BE SOME SLEET MIXED IN...BUT THE BULK OF THE PRECIP LOOKS TO BE FREEZING RAIN AND/OR DRIZZLE. OUR CONFIDENCE ON THE AMOUNT OF ICING IS MODERATE AT BEST...SINCE WE HAVE HAD A SHORT DURATION WARM SPELL AND MUCH OF THE PRECIP MAY TURN OUT BE RATHER LIGHT IN INTENSITY. THAT SAID...WE DO ANTICIPATE A FEW HUNDREDTHS OF AN INCH OF FREEZING RAIN ON VARIOUS SURFACES. KEEP IN MIND THAT THE TALLER BRIDGES OF THE AREA CAN FREEZE BEFORE ROAD SURFACES. THE DON HOLT BRIDGE IN THE CHARLESTON AREA PROBABLY HAS THE BEST CHANCE OF EXPERIENCING ANY ICING PROBLEMS TUESDAY MORNING...BUT WE CAN/T ENTIRELY DISCOUNT THE RAVENEL AND WANDO BRIDGES ALSO GETTING SOME ICE ON THEM. DEPENDING UPON THE INTENSITY OF THE PRECIP WE MAY NEED TO EXPAND THE ADVISORY A LITTLE FURTHER SOUTH INTO GEORGIA AT A LATER TIME. TEMPS LOOK TO BE ABOVE FREEZING IN THE EARLY TO MID AFTERNOON...THUS ANY FREEZING PRECIP WILL CHANGE OVER TO LIQUID BEFORE TAPERING OFF LATE. FOR NOW WE BELIEVE THAT THE PRECIP OVER MUCH OF SE GA...ESPECIALLY TO THE SOUTH OF I-16 WILL BE ALL OR MAINLY LIQUID WITH QPF/S OF 1/10 TO 1/4 INCH TO OCCUR. TEMPS WON/T GO MUCH OF ANYWHERE...EVEN DROPPING A COUPLE OF DEGREES DUE TO THE PRECIP...AND WE/LL BE MAINLY IN THE LOWER AND MIDDLE 30S NORTH/NW TO THE LOWER 40S SOUTH. TUESDAY NIGHT...THE SURFACE WAVE OVER THE ATLANTIC AND THE ASSOCIATED FORCING PULL AWAY AS A MESO-HIGH BUILDS FROM THE WEST. THIS WILL TEMPORARILY SHUT OFF THE PRECIP...AND WE WILL NEED TO WATCH FOR POSSIBLE RE-FREEZING OF THE EARLIER RAINS...ESPECIALLY OVER THE CHARLESTON QUAD-COUNTY DISTRICT. WEDNESDAY AND WEDNESDAY NIGHT...A POTENT SHORT WAVE IN THE DESERT SW TODAY WILL SHIFT THROUGH THE SOUTHERN PLAINS WEDNESDAY AND HEADS INTO THE SE AT NIGHT. THIS TRIGGERS SURFACE CYCLOGENESIS IN THE NORTHERN GULF OF MEXICO BEFORE THE LOW TRACKS JUST OFF THE LOCAL COASTS BY LATE IN THE PERIOD. LARGE SCALE FORCING FROM THESE FEATURES AND A POWERFUL WEST-EAST 150 KT UPPER JET WILL ALLOW FOR CONSIDERABLE OVER-RUNNING RAINS TO DEVELOP BY WEDNESDAY AFTERNOON...BEFORE TAPERING OFF FROM WEST/SW TO EAST/NE LATE WEDNESDAY NIGHT. THIS PROMISES TO BE A PRETTY GOOD SOAKER...WITH PWATS OF 1-1.5 INCHES TO PREVAIL. SOME PLACES COULD EASILY ACHIEVE THESE AMOUNTS GIVEN THAT WE ARE CARRYING CATEGORICAL POPS. RIGHT NOW IT LOOKS TO BE ALL LIQUID UNLESS THE OVER-RUNNING RAINS ARRIVE EARLIER THAN EXPECTED. TEMPS WILL REMAIN FAR BELOW NORMAL. THURSDAY...MUCH DRIER AIR OVERSPREADS THE REGION BEHIND THE EXITING SHORT AVE AND SURFACE LOW...LEADING TO A DRY BUT CHILLY DAY WITH TEMPS AGAIN FAR BELOW SEASONAL NORMS. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A HUMONGOUS AND ROBUST 1040 MB CANADIAN HIGH BUILDING OUT OF THE GREAT PLAINS WILL EXPAND EAST AND SOUTH AND COVERS MUCH OF THE NATION EAST OF THE ROCKIES...INCLUDING THE LOCAL AREA. THIS LEADS TO DRY AND CHILLY CONDITIONS INTO FRIDAY...BEFORE THE HIGH SHIFTS INTO THE ATLANTIC OVER THE WEEKEND AND EARLY NEXT WEEK AND TEMPS BEGIN TO MODERATE. A COASTAL TROUGH WILL LIKELY FORM DURING THIS TRANSITION JUST OFF OUR COAST...AND WE LOOK FOR AT LEAST A SMALL CHANCE OF SHOWERS IN RESPONSE. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... ONGOING VFR CONDITIONS AT KCHS AND KSAV WILL ONLY LAST A FEW MORE HOURS AS RAINFALL AND LOWERING CEILINGS BEGIN TO IMPACT THE TERMINALS. AT KCHS...RAINFALL WILL BECOME STEADY AND PERIODICALLY MODERATE IN INTENSITY. CEILINGS ARE EXPECTED TO FALL TO MVFR BY 08Z...THOUGH VISIBILITIES IN RAIN COULD BE MVFR OR TEMPORARILY IFR AT TIMES. CEILINGS WILL CONTINUE TO STEADILY FALL AND REACH IFR LEVELS AROUND 10Z. THE PRECIPITATION WILL COME TO AN END AROUND 16Z AND THEN LITTLE TO NO RAIN IS EXPECTED THROUGH THE END OF THE FORECAST. IFR CEILINGS WILL STICK THROUGH THE DAY...LIFTING TO MVFR IN THE LATE EVENING HOURS. THE MAIN WIND SHIFT WITH THE FRONT WILL TAKE PLACE AROUND NOON AND WINDS THEREAFTER WILL INCREASE AND BECOME NORTHERLY. AT KSAV...RAINFALL CHANCES ARE MUCH LOWER AND THE OVERALL TIMING OF LOWERING CEILINGS WILL BE ABOUT 2-3 HOURS LATER THAN KCHS. SIMILARLY...IFR CEILINGS WILL SETTLE IN BY LATE MORNING AND REMAIN THROUGH THE DAY. THE WIND SHIFT WITH THE FRONT WILL ARRIVE AT KSAV IN THE EARLY AFTERNOON. AN IMPROVEMENT TO MVFR SHOULD TAKE PLACE CLOSER TO MIDNIGHT. EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS OF VARYING CATEGORIES WILL CONTINUE MUCH OF THE TIME MONDAY NIGHT INTO THURSDAY...ALTHOUGH INTERLUDES OF VFR ARE POSSIBLE BETWEEN RAIN EVENTS. ALSO OF NOTE...THERE IS A SLIGHT CHANCE FOR FREEZING/FROZEN PRECIPITATION LATE MONDAY NIGHT INTO TUESDAY MORNING. && .MARINE... EARLY MORNING UPDATE...A DENSE FOG ADVISORY HAS BEEN ISSUED FOR THE CHARLESTON HARBOR AND THE CHARLESTON COUNTY WATERS. THE CHARLESTON HARBOR PILOT BOAT REPORTED NEAR ZERO VISIBILITY RECENTLY AND WEB CAMS AROUND DOWNTOWN AND THE HARBOR SHOW A SHALLOW BANK OF FOG ACROSS THE AREA. THE EXPECTATION IS THAT THERE IS ALSO DENSE FOG JUST OFFSHORE TOO...THUS THE ADVISORY IS IN EFFECT. THE FOG SHOULD START TO MIX OUT AND DISSIPATE IN THE LATE MORNING HOURS/AROUND NOON AS THE COLD FRONT MOVES IN...WINDS PICK UP AND SHIFT AROUND TO NORTH. TODAY AND TONIGHT...A COLD FRONT WILL SINK SOUTHWARD ACROSS THE REGION AND IS EXPECTED TO PUSH ACROSS THE WATERS MAINLY IN THE AFTERNOON/EVENING HOURS. BEHIND THE FRONT...A SIGNIFICANT NORTH TO NORTHEAST SURGE IS EXPECTED TO BEGIN WITH RAPIDLY INCREASING WINDS AND SEAS. WINDS WILL INCREASE FIRST ACROSS THE CHARLESTON COUNTY WATERS AND THE CHARLESTON HARBOR IN THE EARLY AFTERNOON...REACHING THE GEORGIA WATERS IN THE LATE AFTERNOON AND EARLY EVENING HOURS. THE NEARSHORE WATERS WILL SEE WINDS INCREASE INTO THE 20 TO 25 KT RANGE...INCLUDING THE CHARLESTON HARBOR...WITH GUSTS TO 30 KT POSSIBLE FOR THE OUTER GEORGIA WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL WATERS THROUGH THE OVERNIGHT. THE NORTH TO NORTHEAST SURGE WILL CONTINUE TONIGHT IN THE WAKE OF THE FRONT AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE WATERS. WINDS WILL LIKELY REACH THEIR PEAK IN THE MID TO LATE EVENING HOURS WITH GUSTS TO 30 KT POSSIBLE ACROSS ALL WATERS. SEAS WILL CONTINUE TO INCREASE REACHING 4-6 FT WITHIN 20 NM AND 6-9 FT OUT TO 60 NM. TUESDAY...ONGOING SMALL CRAFT ADVISORIES WILL CONTINUE INTO THE AFTERNOON IN ASSOCIATION WITH THE GRADIENT BETWEEN THE ATLANTIC LOW AND A WEAK INLAND HIGH PRESSURE WEDGE. WHILE WE CAN/T RULE OUT A LITTLE FREEZING RAIN IN CHARLESTON HARBOR...THE BULK OF THE WET WEATHER LOOKS TO BE IN THE FORM OF LIQUID. TUESDAY NIGHT INTO WEDNESDAY...CONDITIONS WILL IMPROVE AS THE ATLANTIC LOW PULLS AWAY AND ANOTHER AREA OF HIGH PRESSURE ARRIVES FROM THE WEST. WINDS AND SEAS WILL BE FAR BELOW ANY ADVISORY THRESHOLDS. LATE WEDNESDAY INTO THURSDAY...CONDITIONS AGAIN WILL DETERIORATE AS INTENSIFYING LOW PRESSURE DEVELOPS IN THE GULF OF MEXICO AND TRACKS OVER OR NEAR THE LOCAL WATERS LATE WEDNESDAY NIGHT/EARLY THURSDAY...BEFORE PULLING AWAY THURSDAY AFTERNOON. SMALL CRAFT ADVISORIES ARE AGAIN LIKELY AS A RESULT. FRIDAY THROUGH SATURDAY...A STRENGTHENING REGION OF CONTINENTAL HIGH PRESSURE WILL OVERSPREAD THE REGION AND GIVEN COLD ADVECTION AND A TIGHTENING OF THE PRESSURE GRADIENT ADDITIONAL SMALL CRAFT ADVISORIES ARE ANTICIPATED. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR GAZ087-088. SC...FREEZING RAIN ADVISORY FROM 4 AM TO 2 PM EST TUESDAY FOR SCZ040-042>045-047>050-052. MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST TUESDAY FOR AMZ352. DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR AMZ330-350. SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 5 PM EST TUESDAY FOR AMZ350. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 5 PM EST TUESDAY FOR AMZ354. SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 10 PM EST TUESDAY FOR AMZ374. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 2 PM EST TUESDAY FOR AMZ330. && $$ NEAR TERM...BSH SHORT TERM... LONG TERM... AVIATION...BSH MARINE...BSH
AREA FORECAST DISCUSSION
NWS CARIBOU ME
934 AM EST MON FEB 23 2015 .SYNOPSIS... A STRONG COLD FRONT WILL CROSS THE AREA THIS MORNING. HIGH PRESSURE WILL BUILD ACROSS NORTHERN NEW ENGLAND TONIGHT AND WILL MOVE EAST TUESDAY. DEVELOPING LOW PRESSURE FROM THE WEST WILL CROSS THE AREA WEDNESDAY THEN MOVE TOWARD THE NORTHERN MARITIMES WEDNESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... 930 AM UPDATE...LATEST RADAR SHOWED AREA OF SNOW AND SQUALLS NOW IN NEW BRUNSWICK. BTV SNOW SQUALL PARAMETER AND 06Z NAM DID A FINE JOB IN PICKING UP THE SNOW SQUALLS AS THEY MOVED THROUGH THE REGION EARLIER THIS MORNING. THE HRRR MODEL AND THE RAP APPEAR TO BE IN STEP W/TEH CURRENT SET PER THE RADAR IMAGERY. A FEW AREAS OF SNOW STILL OCCURRING ACROSS THE REGION. ONE WAS ACROSS AR NORTHERN MAINE NEAR THE FRENCHVILLE REGION COMING OFF ST. LAWRENCE RIVER(STREAMER). THE OTHER AREA WAS MOVING OFF THE MT. KATAHDIN REGION MOVING ACROSS SE AROOSTOOK COUNTY AND NORTHERN WASHINGTON COUNTY. ADDED A 1/2 INCH OF NEW SNOW TO ACCOUNT FOR THESE AREAS OF SNOW. VISIBLE SATELLITE IMAGERY SHOWED PLENTY OF SUNSHINE W/ SCATTERED STRATOCUMULUS. THE SUN COMBINED W/THE CAA TAKING PLACE AIDING IN THE INCREASED WINDS. ADDED AREAS OF BLOWING SNOW TO THE FORECAST FOR THIS AFTERNOON. WILL ADD BLOWING SNOW TO THE WSW COMBINED W/THE WIND CHILL ADVISORY NW WINDS 15-25 MPH SUSTAINED W/GUSTS TO 35 MPH EXPECTED. PREVIOUS DISCUSSION...HIGH TEMPERATURES WILL BE EARLY THIS MORNING, ESPECIALLY IN THE NORTH, THEN TEMPERATURES WILL FALL THROUGH MUCH OF THE DAY UNDER BRISK WEST WINDS. WIND CHILLS WILL QUICKLY DROP TO -15F TO -30F THIS AFTERNOON AND EVENING, SO HAVE CONTINUED WITH THE WIND CHILL ADVISORY FOR OUR ENTIRE FORECAST AREA. MUCH OF THE MODEL GUIDANCE CONTINUES TO INDICATE THE POTENTIAL FOR SNOW SQUALLS AND/OR STREAMERS COMING OFF THE SAINT LAWRENCE OVER FAR NORTHERN AROOSTOOK COUNTY THROUGH MUCH OF THE DAY. AREAS OF BLOWING AND DRIFTING SNOW ARE ALSO A CONCERN ACROSS ALL OF NORTHERN AND CENTRAL MAINE, AS THE GUSTY WINDS WILL EASILY LOFT THE RECENTLY- FALLEN SNOW. ROAD CONDITIONS WILL LIKELY BE POOR IN OPEN TERRAIN WITH SNOW DRIFTS AND VISIBILITY SHARPLY REDUCED TO NEAR ZERO AT TIMES, ESPECIALLY ALONG NORTH-SOUTH ROADS SUCH AS ROUTES 1 AND 11. FOR TONIGHT...THE ARCTIC HIGH WILL BUILD INTO NEW ENGLAND OVERNIGHT. TEMPERATURES WILL PLUMMET THROUGH THE EVENING, WITH LOWS -15F TO -25F ACROSS THE NORTHERN HALF OF OUR FORECAST AREA. DOWNEAST AREAS WILL EVEN DROP BELOW ZERO, WITH LOWS OF -5F TO -15F. WINDS WILL GRADUALLY ABATE LATER TONIGHT IN RESPONSE TO THE WEAKENING PRESSURE GRADIENT UNDER THE RIDGE, ESPECIALLY OVER FAR WESTERN LOCATIONS. THEREFORE, IN SPITE OF THE VERY COLD AIR TEMPERATURES, THE WIND CHILL ADVISORY STILL LOOKS APPLICABLE, AS OPPOSED TO A WIND CHILL WARNING. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... THE CORE OF BITTERLY COLD ARCTIC AIR WILL BE MOVG E OF THE FA TUE MORN. AFT A VERY COLD START TO THE DAY...HI TEMPS SHOULD RECOVER INTO THE SINGLE DIGITS BY MID TO LATE AFTN...WITH DOWNEAST AREAS RECOVERING INTO THE TEENS BY ERLY EVE AS SFC WINDS BECOME SRLY COMPONENT BEHIND DEPARTING SFC HI PRES MOVG E TOWARD THE OPEN ATLC. THIS RETURN FLOW WILL BRING INCREASING CLDNSS FROM S TO N ACROSS THE REGION TUE NGT...WITH LGT SN POSSIBLE TO PTNS OF THE FA LATE TUE NGT. MODELS THEN SHOW A S/WV COMPLEX MOVG E FROM CNTRL CAN AND THE GREAT LKS TUE NGT INTO WED. THE SFC LOW WITH THIS SYSTEM IS XPCTD TO REFORM FROM QB TUE NGT TO A SECONDARY LOW OVR THE S GULF OF ME SW OF NOVA SCOTIA. THE SECONDARY LOW THEN GAINS MOMENTUM WED AFTN...ABSORBING THE OLD PRIMARY LOW FROM QB BY WED EVE. A POCKET OF SRLY LOW TO MID LVL WARM/MOISTURE ADVCN BEGINS TO DEVELOP OVR ERN ME BEGINNING ERLY WED MORN JUST AHEAD OF THE DEVELOPING SECONDARY...RESULTING IN MORE ORGANIZED SNFL CLIPPING ERN ME MON MORN INTO ERLY AFTN BEFORE MOVING ENE INTO NB BY LATE WED AFTN. MODELS VARY WITH REGARD TO THE QPF THAT MAY OCCUR OVR ERN ME WITH THE TMG OF THIS EVENT...WITH THE 00Z DTMNSTC CANGEM AND NAM MOST AGGRESSIVE AND THE GFS AND SPCLY ECMWF THE LEAST. WPC IS LEANING MORE WITH THE GFS AND ECMWF MODELS ATTM...SO WE WEIGHT THESE MODELS MORE WITH FCST 6HRLY QPF AND CORRESPONDING SNFL LATE TUE NGT THRU WED. CONSIDERING THE UNCERTAINTY OF TMG OF DEVELOPMENT OF THE SNFL SHIELD BEFORE THE SECONDARY MOVES AWAY FROM THE REGION...WE KEPT SN TO LIQ RATIOS RELATIVELY CONSERVATIVE AT 13.5 TO 1...WHICH RESULTS IN MAX TOTALS OF 3 TO 4 INCHES OVR SE WASHINGTON COUNTY WHERE WE GO WITH CATEGORICAL POPS WITH LESSER AMOUNTS AND POPS TO THE WNW. SN SHOULD TAPER TO SN SHWRS FROM W TO E ACROSS THE REGION FROM MID AFTN TO ERLY EVE...THEN END FROM S TO N OVRNGT WED...WITH STRONGER LLVL COLD ADVCN XPCTD LATE WED NGT AND ERLY THU MORN WITH A SECONDARY ARCTIC COLD FRONT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... ANOTHER DEEP ARCTIC AIR MASS WILL FOLLOW THE SECONDARY COLD FRONT ACROSS THE REGION FROM CNTRL CAN...WITH THIS AIR MASS NOT QUITE AS COLD AS THE PRIOR AIR MASS AFFECTING THE FA ON TUE. UNDER FAIR SKIES...HI TEMPS WILL BE WELL BLO SEASONAL AVGS FOR THE END OF FEB THU AND FRI...WITH SOME RADIATIONAL COOLING POSSIBLE THU NGT AND MSLY FRI NGT AS LARGE SPRAWLING SFC HI PRES RIDGES ENE INTO THE REGION. WITH WEAK PRES GRAD FLOW INDICATED...THE BEST POTENTIAL FOR COLDEST OVRNGT LOWS WILL BE ACROSS BROAD RVR VLYS OF NRN AND CNTRL PTNS OF THE FA...WITH HILL TOP LCTNS LIKELY MAINTAINING A LGT BREEZE KEEP OVRNGT LOWS NOT AS COLD. ANOTHER WV OF LOW PRES TRACKING OFF THE SE U.S COAST WILL KEEP A LITTLE MORE PRES GRAD AND PERHAPS HI CLD OVR THE DOWNEAST COAST BOTH NGTS LMTG THE POTENTIAL OF VERY COLD LOW TEMPS. SAT SHOULD CONT FAIR...BUT NOT AS COLD AS FCST AFTN 925 MB TEMPS RISE FROM THE LOWER TO MID -20S TO -10S DEG C. WITH THE CNTR OF STRONG SFC HI PRES TRACKING WELL S OF THE FA AS IT MOVES OFF THE MID ATLC COAST...WINDS WILL LIKELY NOT HAVE MUCH CHC TO DECOUPLE EVEN OVR VLY AREAS SAT NGT. SUN WILL BEGIN FAIR...THEN HI/MID CLDNSS INCREASE LATER IN THE DAY AS A LARGE SHIELD OF LGT OVRRNG SNFL APCHS FROM THE GREAT LKS AND QB PROV BY SUN EVE. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... NEAR TERM: MVFR CONDITIONS WITH OCCASIONAL IFR IN LIGHT SNOW AT KHUL/KBHB WILL LINGER THROUGH 14Z OR SO TODAY. THEN CONDITIONS WILL GRADUALLY IMPROVE AS A COLD FRONT CROSSES THE AREA AND ALLOWS COLDER AND DRIER AIR TO SPREAD OVER THE REGION. WEST WINDS WILL INCREASE TO 10-15KT WITH GUSTS TO 25KT POSSIBLE. THIS MAY RESULT IN BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO IFR AT TIMES THROUGH THIS EVENING. OTHERWISE, PREVAILING VFR CONDITIONS ARE EXPECTED FROM 15Z SOUTH/21Z NORTH WITH CLEARING SKIES. SHORT TO LONG TERM: VFR XPCTD ALL TAF SITES TUE THRU TUE EVE...WITH MVFR CLGS POSSIBLE LATE TUE NGT AND THEN MVFR OR IFR VSBYS WITH LGT SNFL DURING THE DAY WED. AFTWRDS...MVFR CLGS CONT ACROSS NRN TAF SITES WED NGT INTO THU MORN WHILE DOWNEAST SITES BECOME VFR. ALL SITES THEN BECOME VFR THU AFTN AND CONT SO THRU FRI. && .MARINE... NEAR TERM: A GALE WARNING REMAINS IN PLACE FOR TODAY AND TONIGHT. A COLD FRONT WILL CROSS THE WATERS THIS MORNING, FOLLOWED BY WEST TO NORTHWEST WINDS OF 20 TO 30 KT WITH GUSTS IN EXCESS OF 35 KT. BITTERLY COLD TEMPERATURES AND THE STRONG WINDS WILL COMBINE TO CREATE HEAVY FREEZING SPRAY, ESPECIALLY OVER THE OUTER WATERS, SO THE FREEZING SPRAY WARNING REMAINS IN PLACE FOR LATER TODAY THROUGH TONIGHT. SHORT TO LONG TERM: SCA OR LESS CONDITIONS XPCTD THRU THIS PTN OF THE FCST. HVY FZGSPY SHOULD BECOME MDT BY 12Z TUE...BECOMING LGT BY LATE DAY AND THEN ENDING BY WED MORN AS COLD ADVCN DIMINISHES OVR THE WATERS AND EVENTUALLY REVERSES TO WARM ADVCN. WENT ABV WW3 GUIDANCE FOR FCST WV HTS BY A FACTOR OF 1.15 OR SO...BASED ON BIAS TRENDS OBSVD OVR THE PAST FEW WEEKS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WIND CHILL ADVISORY FROM 3 PM THIS AFTERNOON TO 10 AM EST TUESDAY FOR MEZ001>006-010-011-031-032. WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR MEZ015>017-029-030. MARINE...HEAVY FREEZING SPRAY WARNING FROM 3 PM THIS AFTERNOON TO 7 AM EST TUESDAY FOR ANZ050>052. GALE WARNING UNTIL 4 AM EST TUESDAY FOR ANZ050>052. && $$ NEAR TERM...HASTINGS/HEWITT SHORT TERM...VJN LONG TERM...VJN AVIATION...HASTINGS/HEWITT/VJN MARINE...HASTINGS/HEWITT/VJN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
637 AM EST MON FEB 23 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 532 AM EST MON FEB 23 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT RIDGE FROM THE ERN PACIFIC INTO BC AND MID LEVEL LOW NEAR JAMES BAY RESULTING IN NNW FLOW FROM NRN CANADA INTO THE WRN GREAT LAKES. A VIGOROUS UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER NRN CANADA. AT THE SFC...LIGHT WRLY FLOW PREVAILED ACROSS THE REGION AS ARCTIC HIGH PRES SLOWLY BUILDS TO THE SE TO WRN IA. WITH THE EXTENSIVE ICE COVER ACROSS LAKE SUPERIOR...RADAR/SATELLITE INDICATED ONLY MINIMAL/WEAK LES TO NEAR MUNISING AND GRAND MARAIS THAT WAS SLOWLY LIFTING OFFSHORE AS WINDS BACK. EARLY MORNING TEMPS GENERALLY RANGING BETWEEN -10F TO -20F ALONG WITH WINDS AROUND 5 MPH PRODUCED WIND CHILLS IN THE -20 TO -35 RANGE. TODAY...WIND CHILL VALUES WILL ONLY SLOWLY MODERATE THIS MORNING AS TEMPS CLIMBING BACK TOWARD ZERO WILL BE OFFSET BY INCREASING SW WINDS TO AROUND 10 MPH. OTHERWISE...QUIET WEATHER IS EXPECTED WITH GRADUALLY INCREASING MID AND HIGH CLOUDS IN THE WAA PATTERN BETWEEN THE RETREATING HIGH AND THE CLIPPER LOW MOVING SSE FROM CANADA. THE TIGHTENING PRES GRADIENT WILL BRING GUSTY WINDS BY LATE TODAY MAKING IT STILL FEEL VERY COLD EVEN AS TEMPS CLIMB TO HIGHS NEAR 10F. TONIGHT...THE NRN CANADA SHRTWV WILL QUICKLY DIVE TO THE SSE TO THE NORTH SHORE OF LAKE SUPERIOR BY 12Z/TUE. THE WAA AND PATTERN AND 280K ISENTROPIC LIFT AHEAD OF THE TROUGH WILL BRING WIDESREAD LIGHT SNOW TO THE REGION. EXPECT A DELAY TO THE ONSET OF SNOW TIL LATE EVENING AND OVERNIGHT GIVEN THE VERY DRY AIRMASS IN PLACE OVER THE REGION AND THE TIME TO SATURATE THE 925-700 MB LAYER...PER FCST SOUNDINGS. POTENTIAL SNOWFALL AMOUNTS OF A HALF INCH TO AROUND 2 INCHES ARE CONSISTENT WITH 1.0-1.5 G/KG AVAILABLE DURING THE PERIOD OF STRONGER LIFT AND QPF BETWEEN 0.03-0.08 WITH SLR VALUES AROUND 20/1. THE GREATEST AMOUNTS ARE EXPECTED FROM THE KEWEENAW INTO THE ERN CWA WHERE THE FCST LIFT AND A LONGER PERIOD OF SATURATION IS FCST. POTENTIAL FOR LAKE ENHANCEMENT WITH SW FLOW OFF OF SOME REMAINING OPEN WATER IN NRN LAKE MI SHOULD REMAIN MAINLY EAST OF THE CWA...PER HIGHER RES MODELS 230-250 FCST LOW LEVEL FLOW DIRECTION. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 250 AM EST MON FEB 23 2015 TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR. WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY- TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO WNW WINDS. SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE. WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR. THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS -25 TO -34F. LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS SHOULD BE MUCH LIGHTER. THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS. LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON- EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS. EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR 20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING OUT OF THE CENTRAL PLAINS/. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 637 AM EST MON FEB 23 2015 AFTER A PERIOD OF MVFR CIGS EARLY AT KMCX FROM LIMITED MOISTENING FROM UPSTREAM GAPS IN THE ICE COVER ON LAKE SUPERIOR...A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HIGH PRES MOVING INTO THE OH RIVER VALLEY WILL RESULT IN VFR CONDITIONS AT ALL 3 TAF SITES INTO THIS EVENING. THE SW WINDS WILL STRENGTHEN AND TURN GUSTY THIS AFTERNOON AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FRONT APPROACHING FROM THE NW. SNOW IN ADVANCE OF THIS FRONT WILL ARRIVE FROM NW TO SE LATE THIS EVENING. THE DRY NATURE OF THE ANTECEDENT AIRMASS WILL MAINTAIN VFR CONDITIONS INITIALLY DESPITE THE THICKENING CLOUDD COVER. HOWEVER...CONDITIONS WILL DROP TO MVFR AFT 06Z AND LIKELY TO IFR AT CMX WHERE THE HEAVIER SNOW IS EXPECTED. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 532 AM EST MON FEB 23 2015 SOUTHWEST WINDS WILL QUICKLY INCREASE THIS AFTERNOON BETWEEN LOW PRESSURE DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO AND HIGH PRES MOVING INTO THE OH VALLEY. THIS WILL LEAD TO SOUTHWESTERLY GALES OF 35-40KTS OVER PORTIONS OF LAKE SUPERIOR THIS AFTERNOON AND EVENING. A GALE WARNING REMAINS IN EFFECT FOR MUCH OF WESTERN/CENTRAL LAKE SUPERIOR FOR LATE THIS AFTERNOON AND TONIGHT. THEN AS A COLD FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE TONIGHT INTO TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST...THERE MAY BE A FEW GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS BELOW 20KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR MIZ001>007-009>014-084-085. LAKE SUPERIOR... GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR LSZ266. GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
532 AM EST MON FEB 23 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 532 AM EST MON FEB 23 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT RIDGE FROM THE ERN PACIFIC INTO BC AND MID LEVEL LOW NEAR JAMES BAY RESULTING IN NNW FLOW FROM NRN CANADA INTO THE WRN GREAT LAKES. A VIGOROUS UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER NRN CANADA. AT THE SFC...LIGHT WRLY FLOW PREVAILED ACROSS THE REGION AS ARCTIC HIGH PRES SLOWLY BUILDS TO THE SE TO WRN IA. WITH THE EXTENSIVE ICE COVER ACROSS LAKE SUPERIOR...RADAR/SATELLITE INDICATED ONLY MINIMAL/WEAK LES TO NEAR MUNISING AND GRAND MARAIS THAT WAS SLOWLY LIFTING OFFSHORE AS WINDS BACK. EARLY MORNING TEMPS GENERALLY RANGING BETWEEN -10F TO -20F ALONG WITH WINDS AROUND 5 MPH PRODUCED WIND CHILLS IN THE -20 TO -35 RANGE. TODAY...WIND CHILL VALUES WILL ONLY SLOWLY MODERATE THIS MORNING AS TEMPS CLIMBING BACK TOWARD ZERO WILL BE OFFSET BY INCREASING SW WINDS TO AROUND 10 MPH. OTHERWISE...QUIET WEATHER IS EXPECTED WITH GRADUALLY INCREASING MID AND HIGH CLOUDS IN THE WAA PATTERN BETWEEN THE RETREATING HIGH AND THE CLIPPER LOW MOVING SSE FROM CANADA. THE TIGHTENING PRES GRADIENT WILL BRING GUSTY WINDS BY LATE TODAY MAKING IT STILL FEEL VERY COLD EVEN AS TEMPS CLIMB TO HIGHS NEAR 10F. TONIGHT...THE NRN CANADA SHRTWV WILL QUICKLY DIVE TO THE SSE TO THE NORTH SHORE OF LAKE SUPERIOR BY 12Z/TUE. THE WAA AND PATTERN AND 280K ISENTROPIC LIFT AHEAD OF THE TROUGH WILL BRING WIDESREAD LIGHT SNOW TO THE REGION. EXPECT A DELAY TO THE ONSET OF SNOW TIL LATE EVENING AND OVERNIGHT GIVEN THE VERY DRY AIRMASS IN PLACE OVER THE REGION AND THE TIME TO SATURATE THE 925-700 MB LAYER...PER FCST SOUNDINGS. POTENTIAL SNOWFALL AMOUNTS OF A HALF INCH TO AROUND 2 INCHES ARE CONSISTENT WITH 1.0-1.5 G/KG AVAILABLE DURING THE PERIOD OF STRONGER LIFT AND QPF BETWEEN 0.03-0.08 WITH SLR VALUES AROUND 20/1. THE GREATEST AMOUNTS ARE EXPECTED FROM THE KEWEENAW INTO THE ERN CWA WHERE THE FCST LIFT AND A LONGER PERIOD OF SATURATION IS FCST. POTENTIAL FOR LAKE ENHANCEMENT WITH SW FLOW OFF OF SOME REMAINING OPEN WATER IN NRN LAKE MI SHOULD REMAIN MAINLY EAST OF THE CWA...PER HIGHER RES MODELS 230-250 FCST LOW LEVEL FLOW DIRECTION. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 250 AM EST MON FEB 23 2015 TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR. WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY- TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO WNW WINDS. SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE. WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR. THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS -25 TO -34F. LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS SHOULD BE MUCH LIGHTER. THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS. LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON- EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS. EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR 20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING OUT OF THE CENTRAL PLAINS/. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1220 AM EST MON FEB 23 2015 A STEADY WNW SLOWLY BACKING SW FLOW OF DRY AIR TO THE N OF HI PRES MOVING INTO THE OH RIVER VALLEY WL RESULT IN VFR CONDITIONS AT ALL 3 TAF SITES INTO THIS EVNG. ALTHOUGH THE W WIND WL UPSLOPE INTO CMX EARLY THIS MRNG...THE UPSTREAM AIRMASS IS SO DRY AND LK SUP SUFFICIENTLY ICE COVERED TO LIMIT THE POTENTIAL FOR LES OR EVEN MUCH IN THE WAY OF LK CLDS. THE SW WINDS WL STRENGTHEN AND TURN GUSTY THIS AFTN AS THE PRES GRADIENT TIGHTENS AHEAD OF A COLD FNT APRCHG FM THE NW. SN IN ADVANCE OF THIS FNT WL ARRIVE NW-SE LATE THIS EVNG. DRY NATURE OF THE ANTECEDENT AIRMASS WL MAINTAIN VFR CONDITIONS INITIALLY DESPITE THE THICKENING CLD COVER AND ARRIVING -SN. BEST CHC FOR MVFR CONDITIONS BEFORE 24/06Z WL BE AT CMX...WHERE THE PCPN WL ARRIVE EARLIEST. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 532 AM EST MON FEB 23 2015 SOUTHWEST WINDS WILL QUICKLY INCREASE THIS AFTERNOON BETWEEN LOW PRESSURE DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO AND HIGH PRES MOVING INTO THE OH VALLEY. THIS WILL LEAD TO SOUTHWESTERLY GALES OF 35-40KTS OVER PORTIONS OF LAKE SUPERIOR THIS AFTERNOON AND EVENING. A GALE WARNING REMAINS IN EFFECT FOR MUCH OF WESTERN/CENTRAL LAKE SUPERIOR FOR LATE THIS AFTERNOON AND TONIGHT. THEN AS A COLD FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE TONIGHT INTO TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST...THERE MAY BE A FEW GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS BELOW 20KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR MIZ001>007-009>014-084-085. LAKE SUPERIOR... GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR LSZ266. GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1015 AM EST MON FEB 23 2015 .SYNOPSIS..AN AREA OF LOW PRESSURE AND ATTENDANT COLD FRONT WILL PUSH SOUTH AND EAST OF THE AREA LATER THIS MORNING. ARCTIC HIGH PRESSURE WILL BUILD INTO OUR AREA THIS AFTERNOON THROUGH TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM MONDAY... A LOW AMPLITUDE SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ARE DEPARTING THE SC COAST THIS MORNING. ANAFRONTAL PRECIP MAINLY SOUTHEAST OF THE TRIANGLE AREA WILL ALSO CONTINUE TO EXIT TO THE EAST THROUGH EARLY AFTERNOON. WEAK COLD ADVECTION WILL PERSIST THIS AFTERNOON BEFORE THE STRONGER SURGE OCCURS THIS EVENING AHEAD THE ARCTIC HIGH BUILDING ACROSS THE CENTRAL APPALACHIANS. DUE TO THE DELAYED ARRIVAL OF COLDER LOW-LEVEL AIR...THE WETBULB FREEZING LINE IS STILL WELL TO OUR NORTH IN CENTRAL VA AND BY THE TIME IT SINKS SOUTH IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON... ALL DEEPER MOISTURE AND PRECIP WILL EITHER HAVE DEPARTED OR PRECIP WON`T BE OF SUFFICIENT INTENSITY TO CAUSE WETBULBING OR ANY WINTRY IMPACTS. LATEST GUIDANCE REFLECTS THIS. WILL KEEP THE GENERAL TREND OF POPS GOING AND JUST MAKE SOME ALTERATIONS TO ACCOUNT FOR LATEST RADAR....WITH POPS ENDING AFTER 18Z. WILL ALSO HAVE AN EYE ON THE POTENTIAL FOR A MESOSCALE BAND OF SHALLOW MOISTURE AND PRECIP (MOST LIKELY SLEET BASED ON TEMPS AROUND -10C IN THE SHALLOW SATURATED LAYER) IN THE 21Z TO 03Z TIME FRAME...THOUGH NO IMPACT WOULD BE EXPECTED AT THIS TIME. HI-RES MODELS ARE STILL SPLIT ON WHETHER OR NOT THIS WILL DEVELOP...BUT MODELS HAVE BEEN SHOWING SOMETHING OF THIS NATURE FOR MULTIPLE RUNS. REGARDING TEMPS...THICKNESSES WILL STEADILY FALL THROUGHOUT THE DAY IN THE NORTHEAST FLOW...SO FOR MANY LOCATIONS HIGHS IN THE UPPER 30S NORTH TO MID 40S SOUTH HAVE ALREADY OCCURRED. THE HRRR SHOWS SOME INTERMITTENT BREAKS IN CLOUDS OVER THE THE NORTHWEST PIEDMONT WITH WESTERLY FLOW ALOFT AND NOT AS MUCH LOW-LEVEL MOISTURE THERE. NOT CONFIDENT IN THE UPPER 40S THE HRRR GIVES...BUT THERE COULD BE A LITTLE WARMING THROUGH EARLY AFTERNOON. TONIGHT: THE SECOND BATCH OF S/W ENERGY MOVES INTO THE AREA BETWEEN 06 TO 12Z TUESDAY. RESULTANT WEAK DPVA AND SHALLOW ISENTROPIC UPGLIDE WILL RE-NEW/DEEPEN SATURATION ALOFT TO SUPPORT SOME LIGHT SNOW AND FLURRIES INTO THE AREA AROUND DAYBREAK ACROSS THE WESTERN AND SOUTHERN PORTIONS OF THE FORECAST AREA. MODELS ARE ONLY GENERATING A HUNDREDTH OR TWO ACROSS THE AREA SO NO ACCUMULATION ARE EXPECTED. CAA WILL GOVERN LOWS TONIGHT...RANGING FROM UPPER TEENS ACROSS THE NE TO MID 20S SOUTH. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 330 AM MONDAY... TRANSITORY ARCTIC HIGH PRESSURE WILL HAVE SETTLED ACROSS THE HEART OF CENTRAL NC BY TUESDAY MORNING. THIS HIGH PRESSURE WILL BE NUDGED OFFSHORE BY LATE DAY AS A FAST MOVING SHORT WAVE MOVES EAST ACROSS THE AREA. BRIEF SOUTHERLY FLOW AND WEAK SUPPORT ALOFT WILL POTENTIALLY PRODUCE SOME LIGHT SNOW/FLURRIES...MAINLY ACROSS THE SOUTHERN TIER AND THE WESTERN PIEDMONT TUESDAY MORNING THROUGH AROUND MID DAY. OTHERWISE...SKIES WILL REMAIN BE MOSTLY CLOUDY THROUGH THE DAY WITH HIGHS PEAKING IN THE MID TO UPPER 30S. MINOR MODERATION IN MIN TEMPS IS EXPECTED TUE NIGHT WITH DOWNSLOPE WARMING IN GENERALLY WESTERLY LOW LEVEL FLOW AIDED BY STREAMING MID TO HIGH CLOUDINESS ALOFT IN THE FAST CONFLUENT FLOW. MINS WILL BE MOSTLY IN THE MID 20S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 330 AM MONDAY... A SOUTHERN STREAM SHORT WAVE MOVING ACROSS THE SOUTHEASTERN GULF STATES HAS BEEN ADVERTISED FOR THE MIDWEEK FOR THE PAST FEW DAYS. THIS SHORT WAVE WILL INDUCE CYCLOGENESIS ALONG THE SOUTHERN STREAM MOISTURE PLUME/STALLED FRONTAL ZONE. THE RESULTING LOW WILL MOVE NORTHEAST ACROSS NORTHERN FLORIDA AND GRAZE THE AREA AS IT MOVES OFF INTO THE MID ATLANTIC. RAIN WILL SPREAD INTO THE SOUTHERN TIER AS EARLY AS WEDNESDAY AFTERNOON...WITH BETTER CHANCES DURING THE OVERNIGHT. COLD AIR WILL BE SURGING SOUTH BEHIND THE LOW...AND EXPECT A SOUTHERLY TRANSITION TO SNOW OVERNIGHT AS MINS FALL INTO THE MID AND UPPER 20S. A CHANCE OF SNOW WILL LINGER INTO THURSDAY MORNING EAST OF INTERSTATE 95...OTHERWISE SKIES WILL REMAIN CLOUDY WITH HIGHS SUFFERING ANOTHER SETBACK AS REINFORCING HIGH PRESSURE AGAIN SETTLES DOWN THE COAST. THURSDAYS HIGHS WILL BE IN THE UPPER 30S NORTH TO LOWER 40S SOUTH. HAVE LITTLE CONFIDENCE IN NAILING DOWN THE FEATURES OF POTENTIAL PRECIP PRODUCING SYSTEMS AS THE WEEKEND APPROACHES IN THIS STUBBORN SPLIT FLOW REGIME...I.E. EVOLUTION AND TIMING OF NORTHERN VS SOUTHERN STREAM FEATURES AND THEIR REFUSAL TO COME INTO PHASE. CONFIDENCE IS HIGH THAT HIGHS FRIDAY THROUGH SUNDAY WILL REMAIN WELL BELOW NORMAL...GENERALLY IN THE UPPER 30S TO LOWER 40S FRIDAY AND SATURDAY...AND LOW AMPLITUDE RIDGING LATE THIS WEEKEND WILL PRODUCE A WARMUP SUNDAY...WITH PERHAPS NEAR NORMAL HIGHS ON MONDAY. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... AS OF 620 AM MONDAY... 24HR TAF PERIOD: UPPER LEVEL DISTURBANCES TRACKING THROUGH THE SOUTHEAST US THIS MORNING WILL SUPPORT WEAK ISENTROPIC LIFT AS A WEAK AREA OF LOW PRESSURE DEVELOPS ALONG THE SOUTHWARD SINKING COLD FRONT. THE STEADIER...MORE WIDESPREAD RAIN WILL TRACK ACROSS THE SE PORTIONS OF THE AREA AND WILL AFFECT KFAY THROUGH 15Z-17Z. RDU AND RWI WILL SEE SOME LIGHT PATCHY RAIN DURING THE SAME PERIOD...WHILE KGSO AND KINT WILL LIKELY REMAIN DRY. CIGS ARE EXPECTED TO GENERALLY RANGE FROM MVFR NW TO POSSIBLY IFR/LIFR SOUTHEAST. STRONG CAA DURING THE DAY WILL RESULT IN NELY WIND GUSTS OF 20 TO 25KTS STRONGEST AT KFAY. ADDITIONALLY...COULD SEE A BRIEF CHANGEOVER TO SNOW OR SLEET THIS AFTERNOON AS COLD AIR BUILDS INTO THE AREA FROM THE NORTH. LOW-LEVEL DRY AIR FEED SHOULD ALLOW CIGS TO LIFT TO VFR AT KGSO/KINT BY THE AFTERNOON... WITH KRDU/KFAY/KRWI DELAYED UNTIL THE EVENING. SUB-VFR CONDITIONS COULD SPREAD BACK INTO THE KINT AND KGSO BETWEEN 06 TO 12Z TUESDAY AS ANOTHER BATCH OF UPPER DISTURBANCES MOVES INTO THE REGION ALONG WITH SNOW FLURRIES. OUTLOOK: COULD SEE A PERIOD OF IFR TO MVFR CONDITIONS WITH FLURRIES ON TUESDAY AS ANOTHER UPPER LEVEL DISTURBANCE TRACKS THROUGH THE REGION. AN AREA OF LOW PRESSURE TRACKING NE FROM THE GULF OF MEXICO TO THE SOUTHEAST COAST MAY SPREAD PRECIPITATION WITH ADVERSE AVIATION CONDITIONS INTO THE AREA WEDNESDAY NIGHT INTO THURSDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL/BLS NEAR TERM...CBL/BLS SHORT TERM...MLM LONG TERM...MLM AVIATION...CBL
AREA FORECAST DISCUSSION
NWS TULSA OK
539 AM CST MON FEB 23 2015 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. WIDESPREAD LIGHT SNOW WILL TRACK ACROSS NE OK / FAR NW AR WITH MINIMAL FLIGHT IMPACTS EXPECTED. MORE WIDESPREAD AND PROLONGED AVIATION IMPACTS ARE EXPECTED ACROSS SE OK INTO WEST CENTRAL ARKANSAS W/ MVFR TO IFR CONDITIONS LIKELY. PRECIP WILL DIMINISH BY EARLY EVENING WITH A TREND TOWARD VFR / MVFR CEILINGS. && .PREV DISCUSSION... /ISSUED 406 AM CST MON FEB 23 2015/ DISCUSSION... ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS. COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR PLUNGES SOUTH BY THURSDAY. HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW BEYOND THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... TUL 25 17 43 25 / 30 10 10 10 FSM 29 23 42 26 / 60 20 10 10 MLC 27 17 40 26 / 70 20 10 10 BVO 24 14 44 20 / 20 10 10 10 FYV 24 17 40 21 / 30 10 10 10 BYV 23 18 39 24 / 20 10 10 10 MKO 26 20 42 24 / 40 10 10 10 MIO 25 16 40 23 / 20 10 10 10 F10 25 19 42 26 / 60 10 10 10 HHW 29 22 37 28 / 80 20 10 20 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053- OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075- OKZ076. AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020- ARZ029. && $$ AVIATION...07
AREA FORECAST DISCUSSION
NWS TULSA OK
406 AM CST MON FEB 23 2015 .DISCUSSION... ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS. COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR PLUNGES SOUTH BY THURSDAY. HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW BEYOND THURSDAY. && .PRELIMINARY POINT TEMPS/POPS... TUL 25 17 43 25 / 30 10 10 10 FSM 29 23 42 26 / 60 20 10 10 MLC 27 17 40 26 / 70 20 10 10 BVO 24 14 44 20 / 20 10 10 10 FYV 24 17 40 21 / 30 10 10 10 BYV 23 18 39 24 / 20 10 10 10 MKO 26 20 42 24 / 40 10 10 10 MIO 25 16 40 23 / 20 10 10 10 F10 25 19 42 26 / 60 10 10 10 HHW 29 22 37 28 / 80 20 10 20 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053- OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075- OKZ076. AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020- ARZ029. && $$ SHORT TERM...07 LONG TERM....14
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
530 AM CST MON FEB 23 2015 .AVIATION UPDATE...FOR 12Z TAF PACKAGE... CURRENT CONDITIONS WILL LIKELY PERSIST THROUGH ENTIRE TAF PERIOD. THERE IS SOME CONCERN FOR -FZDZ THIS MORNING FOR KAUS SO INCLUDED TEMPO GROUP TO HANDLE THAT. OTHERWISE -DZ EXPECTED FOR ALL TERMINALS TODAY. AS PREVIOUS FORECAST MENTIONED...ICING WILL BE A CONCERN FOR THE LOWEST 3KFT JUST OFF THE SURFACE DURING TAKEOFF AND LANDING FOR ALL TERMINALS. OTHERWISE...MVFR/IFR CEILINGS ARE EXPECTED THROUGHOUT THE DAY AND NIGHT. GUSTY WINDS WILL ALSO PERSIST THROUGH THE DAY. && .PREV DISCUSSION... /ISSUED 457 AM CST MON FEB 23 2015/ SHORT TERM (TODAY THROUGH TUESDAY)... EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP. OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM TODAY. OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING. WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE WEST. LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)... ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 34 30 43 36 58 / 70 30 20 30 30 AUSTIN BERGSTROM INTL AIRPORT 35 30 43 34 57 / 70 30 20 30 30 NEW BRAUNFELS MUNI AIRPORT 36 32 45 37 61 / 60 30 10 30 20 BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20 DEL RIO INTL AIRPORT 38 36 52 41 68 / 50 10 10 10 - GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30 HONDO MUNI AIRPORT 37 33 48 38 65 / 50 20 10 20 - SAN MARCOS MUNI AIRPORT 36 31 44 37 59 / 70 30 10 30 20 LA GRANGE - FAYETTE REGIONAL 38 33 43 38 57 / 70 40 20 30 30 SAN ANTONIO INTL AIRPORT 38 32 45 38 62 / 60 30 10 20 10 STINSON MUNI AIRPORT 39 33 46 39 63 / 60 30 10 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL VERDE...WILLIAMSON. && $$ MESOSCALE/AVIATION...03 SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
457 AM CST MON FEB 23 2015 .SHORT TERM (TODAY THROUGH TUESDAY)... EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP. OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM TODAY. OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING. WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE WEST. && .LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)... ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 34 30 43 36 58 / 70 30 20 30 30 AUSTIN BERGSTROM INTL AIRPORT 35 30 43 34 57 / 70 30 20 30 30 NEW BRAUNFELS MUNI AIRPORT 36 32 45 37 61 / 60 30 10 30 20 BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20 DEL RIO INTL AIRPORT 38 36 52 41 68 / 50 10 10 10 - GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30 HONDO MUNI AIRPORT 37 33 48 38 65 / 50 20 10 20 - SAN MARCOS MUNI AIRPORT 36 31 44 37 59 / 70 30 10 30 20 LA GRANGE - FAYETTE REGIONAL 38 33 43 38 57 / 70 40 20 30 30 SAN ANTONIO INTL AIRPORT 38 32 45 38 62 / 60 30 10 20 10 STINSON MUNI AIRPORT 39 33 46 39 63 / 60 30 10 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL VERDE...WILLIAMSON. && $$ MESOSCALE/AVIATION...03 SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
946 AM PST MON FEB 23 2015 .SYNOPSIS...AN UPPER LEVEL SYSTEM OVER THE REGION WILL RESULT IN A SLIGHT CHANCE OF SHOWERS AND EMBEDDED THUNDERSTORMS OVER PORTIONS OF MONTEREY AND SAN BENITO COUNTIES THIS AFTERNOON. DRY AND MILD WEATHER WILL RETURN TUESDAY AND PERSIST THROUGH MIDWEEK, THEN A POSSIBLE PATTERN CHANGE WILL POTENTIALLY BRING PRECIPITATION BACK TO THE REGION BY THE END OF THE WEEK. && .DISCUSSION...AS OF 8:50 AM PST MONDAY...UPPER LEVEL LOW CONTINUES TO ROTATE OFF TO OUR SOUTHEAST WITH LIMITED INSTABILITY AND MOISTURE FORECAST TO BE ACROSS SAN BENITO AND INTERIOR MONTEREY COUNTY THROUGH THE DAY. LATEST RUN OF THE HRRR SHOWS A FEW SHOWERS POPPING UP AROUND NOON AND CONTINUING TO ABOUT SUNSET. WILL ALSO KEEP A MENTION OF THUNDERSTORMS GOING AS WELL. WINDS ARE STILL LOCALLY GUSTY OVER THE NORTH AND EAST HILLS ALTHOUGH SPEEDS SHOULD CONTINUE TO DIMINISH THROUGH THE DAY. OUTSIDE OF THOSE ISSUES...QUIET WEATHER ACROSS OUR CWA WITH HIGHS GENERALLY IN THE 60S. CURRENT FORECAST APPEARS ON TRACK SO NO MAJOR UPDATES PLANNED AT THIS TIME. .PREVIOUS DISCUSSION...GENERALLY CLEAR SKIES ACROSS THE REGION THIS MORNING AS A COOL...DRY AIR MASS REMAINS ALOFT. NORTHERLY WINDS CONTINUE TO BE BREEZY WITH GUSTS OF 40 TO 50 MPH IN THE MOST EXPOSED LOCATIONS IN THE HIGHER ELEVATIONS ACROSS THE NORTH BAY AND EAST BAY. THIS HAS RESULTED IN A GOOD AMOUNT OF MIXING AND TEMPERATURES GENERALLY REMAIN IN THE 50S IN MOST VALLEY LOCATIONS ACROSS THE NORTH. EXPECTING THESE WIND SPEEDS TO PERSIST THROUGH THE MORNING HOURS AND WILL KEEP THE WIND ADVISORY IN EFFECT UNTIL 10 AM PST. AS THE PRESSURE GRADIENT RELAXES...WIND SPEEDS WILL DIMINISH SOME BY THIS AFTERNOON. THE MID/UPPER LEVEL SYSTEM THAT BROUGHT SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE REGION YESTERDAY CONTINUES TO BE POSITIONED OVER CENTRAL CALIFORNIA AND NEVADA AT THIS HOUR. LINGERING MOISTURE COMBINED WITH MID/UPPER LEVEL SUPPORT WILL RESULT IN ISOLATED SHOWERS AND THUNDERSTORMS AGAIN OVER MONTEREY AND SAN BENITO COUNTIES THIS AFTERNOON. HOWEVER...SHOWER ACTIVITY IS EXPECTED TO BE LESS WIDESPREAD TODAY WITH DRIER AIR WRAPPING AROUND THE WESTERN PERIPHERY OF THE UPPER LOW. RAIN CHANCES WILL COME TO AN END BY LATE THIS EVENING AS THE UPPER LEVEL FEATURE EJECTS TOWARD THE DESERT SOUTHWEST ON TUESDAY. MEANWHILE...THE UPPER LEVEL RIDGE OFF OF THE WEST COAST WILL RESULT IN DRY WEATHER CONDITIONS AND A SLIGHT WARMING TREND THROUGH AT LEAST THURSDAY NIGHT. THE FORECAST MODELS CONTINUE TO DEPICT A MID/UPPER LEVEL TROUGH DROPPING OUT OF THE GULF OF ALASKA LATE THIS WEEK THAT WILL THEN SLIDE DOWN THE WEST COAST THIS WEEKEND. AS A RESULT...WILL MAINTAIN PRECIPITATION CHANCES OVER THE NORTH BAY ON FRIDAY AND ACROSS MUCH OF THE REGION INTO SATURDAY NIGHT. WHILE CONFIDENCE HAS INCREASED SLIGHTLY FOR SOME SORT OF A PATTERN CHANGE...THERE REMAINS INCONSISTENCY AMONG THE MEDIUM RANGE MODELS LATE IN THE FORECAST PERIOD. && .AVIATION...AS OF 9:45 AM PST MONDAY...DRY NORTHERLY FLOW WILL CONTINUE ACROSS THE REGION THROUGH TUESDAY...RESULTING IN VFR CONDITIONS AT ALL TERMINALS. LOCAL GUSTY NORTH TO NORTHEAST WINDS ON MONDAY MORNING WILL GRADUALLY TAPER OFF MONDAY AFTERNOON AND EVENING. VICINITY OF KSFO...VFR. LIGHT TO MODERATE NORTH TO NORTHEAST WINDS THROUGH MID AFTERNOON TURNING TO LIGHT NORTHWEST BY LATE AFTERNOON. KSFO BRIDGE APPROACH...SIMILAR TO SFO. MONTEREY BAY AREA TERMINALS...VFR. LIGHT WINDS. && .MARINE...AS OF 3:59 AM PST MONDAY...HIGH PRESSURE WILL CONTINUE OVER THE GREAT BASIN AND NORTHERNMOST CALIFORNIA TODAY AND TONIGHT. THIS WILL RESULT IN A LIGHT TO MODERATE NORTHERLY WIND. WINDS WILL BECOME NORTHWESTERLY OVER THE COASTAL WATERS BY ON TUESDAY. A LOW PRESSURE AREA OVER THE GULF OF ALASKA WILL MOVE TO THE BAY AREA FRIDAY BRINGING WITH IT A CHANCE OF SHOWERS. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 3 PM && $$ PUBLIC FORECAST: BELL/RGASS AVIATION: DYKEMA MARINE: CANEPA VISIT US AT WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
903 AM PST MON FEB 23 2015 .SYNOPSIS...AN UPPER LEVEL SYSTEM OVER THE REGION WILL RESULT IN A SLIGHT CHANCE OF SHOWERS AND EMBEDDED THUNDERSTORMS OVER PORTIONS OF MONTEREY AND SAN BENITO COUNTIES THIS AFTERNOON. DRY AND MILD WEATHER WILL RETURN TUESDAY AND PERSIST THROUGH MIDWEEK, THEN A POSSIBLE PATTERN CHANGE WILL POTENTIALLY BRING PRECIPITATION BACK TO THE REGION BY THE END OF THE WEEK. && .DISCUSSION...AS OF 8:50 AM PST MONDAY...UPPER LEVEL LOW CONTINUES TO ROTATE OFF TO OUR SOUTHEAST WITH LIMITED INSTABILITY AND MOISTURE FORECAST TO BE ACROSS SAN BENITO AND INTERIOR MONTEREY COUNTY THROUGH THE DAY. LATEST RUN OF THE HRRR SHOWS A FEW SHOWERS POPPING UP AROUND NOON AND CONTINUING TO ABOUT SUNSET. WILL ALSO KEEP A MENTION OF THUNDERSTORMS GOING AS WELL. WINDS ARE STILL LOCALLY GUSTY OVER THE NORTH AND EAST HILLS ALTHOUGH SPEEDS SHOULD CONTINUE TO DIMINISH THROUGH THE DAY. OUTSIDE OF THOSE ISSUES...QUIET WEATHER ACROSS OUR CWA WITH HIGHS GENERALLY IN THE 60S. CURRENT FORECAST APPEARS ON TRACK SO NO MAJOR UPDATES PLANNED AT THIS TIME. .PREVIOUS DISCUSSION...GENERALLY CLEAR SKIES ACROSS THE REGION THIS MORNING AS A COOL...DRY AIR MASS REMAINS ALOFT. NORTHERLY WINDS CONTINUE TO BE BREEZY WITH GUSTS OF 40 TO 50 MPH IN THE MOST EXPOSED LOCATIONS IN THE HIGHER ELEVATIONS ACROSS THE NORTH BAY AND EAST BAY. THIS HAS RESULTED IN A GOOD AMOUNT OF MIXING AND TEMPERATURES GENERALLY REMAIN IN THE 50S IN MOST VALLEY LOCATIONS ACROSS THE NORTH. EXPECTING THESE WIND SPEEDS TO PERSIST THROUGH THE MORNING HOURS AND WILL KEEP THE WIND ADVISORY IN EFFECT UNTIL 10 AM PST. AS THE PRESSURE GRADIENT RELAXES...WIND SPEEDS WILL DIMINISH SOME BY THIS AFTERNOON. THE MID/UPPER LEVEL SYSTEM THAT BROUGHT SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO THE REGION YESTERDAY CONTINUES TO BE POSITIONED OVER CENTRAL CALIFORNIA AND NEVADA AT THIS HOUR. LINGERING MOISTURE COMBINED WITH MID/UPPER LEVEL SUPPORT WILL RESULT IN ISOLATED SHOWERS AND THUNDERSTORMS AGAIN OVER MONTEREY AND SAN BENITO COUNTIES THIS AFTERNOON. HOWEVER...SHOWER ACTIVITY IS EXPECTED TO BE LESS WIDESPREAD TODAY WITH DRIER AIR WRAPPING AROUND THE WESTERN PERIPHERY OF THE UPPER LOW. RAIN CHANCES WILL COME TO AN END BY LATE THIS EVENING AS THE UPPER LEVEL FEATURE EJECTS TOWARD THE DESERT SOUTHWEST ON TUESDAY. MEANWHILE...THE UPPER LEVEL RIDGE OFF OF THE WEST COAST WILL RESULT IN DRY WEATHER CONDITIONS AND A SLIGHT WARMING TREND THROUGH AT LEAST THURSDAY NIGHT. THE FORECAST MODELS CONTINUE TO DEPICT A MID/UPPER LEVEL TROUGH DROPPING OUT OF THE GULF OF ALASKA LATE THIS WEEK THAT WILL THEN SLIDE DOWN THE WEST COAST THIS WEEKEND. AS A RESULT...WILL MAINTAIN PRECIPITATION CHANCES OVER THE NORTH BAY ON FRIDAY AND ACROSS MUCH OF THE REGION INTO SATURDAY NIGHT. WHILE CONFIDENCE HAS INCREASED SLIGHTLY FOR SOME SORT OF A PATTERN CHANGE...THERE REMAINS INCONSISTENCY AMONG THE MEDIUM RANGE MODELS LATE IN THE FORECAST PERIOD. && .AVIATION...AS OF 4:12 AM PST MONDAY...IT`S MUCH DRIER AROUND THE AREA. DEWPOINT TEMPS AND HUMIDITY HAVE TUMBLED DOWNWARD AS DOWNSLOPING WINDS OFF THE SIERRA NEVADA AND COASTAL MTNS CONTINUE TO SUPPORT DRY WEATHER /VFR CONDITIONS/ FOR THE PERIOD. AREAS OF GUSTY N-NE WINDS ARE PERSISTING THIS MORNING WITH THE HIGHER GUSTS IN THE EAST AND NORTH BAY MTNS AND HILLS. SURFACE WINDS AT THE KOAK TERMINAL HAVE BEEN LOWERING ENOUGH TO CONSIDER INCLUDING NON-CONVECTIVE LOW LEVEL WIND SHEAR IN THE TAF BUT WILL WAIT ON THIS AS THE SURFACE WINDS HAVE RECENTLY PICKED BACK UP AGAIN. THE NORTHERLY GRADIENT UKI-STS IS STRONG AT 2.5 MB. THE WMC-SFO AND ACV-SFO GRADIENTS ARE 9.1 MB AND 5.3 MB RESPECTIVELY AND THE NAM MODEL FORECASTS THEM TO STRENGTHEN MORE TODAY THEN TAPER OFF SLOWLY BEGINNING VERY LATE TONIGHT AND TUESDAY. EPAC UPPER LEVEL RIDGING WILL SLOWLY EDGE EASTWARD BACK OVER CA THROUGH MID-WEEK. VICINITY OF KSFO...VFR. KSFO BRIDGE APPROACH...SIMILAR TO SFO. MONTEREY BAY AREA TERMINALS...VFR. && .MARINE...AS OF 3:59 AM PST MONDAY...HIGH PRESSURE WILL CONTINUE OVER THE GREAT BASIN AND NORTHERNMOST CALIFORNIA TODAY AND TONIGHT. THIS WILL RESULT IN A LIGHT TO MODERATE NORTHERLY WIND. WINDS WILL BECOME NORTHWESTERLY OVER THE COASTAL WATERS BY ON TUESDAY. A LOW PRESSURE AREA OVER THE GULF OF ALASKA WILL MOVE TO THE BAY AREA FRIDAY BRINGING WITH IT A CHANCE OF SHOWERS. && .MTR WATCHES/WARNINGS/ADVISORIES... .TDAY...WIND ADVISORY...NORTH AND EAST BAY HILLS UNTIL 10 AM SCA...SF BAY NORTH OF THE BAY BRIDGE UNTIL 3 PM && $$ PUBLIC FORECAST: BELL/RGASS AVIATION/MARINE: CANEPA VISIT US AT WEATHER.GOV/SANFRANCISCO FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSBAYAREA WWW.TWITTER.COM/NWSBAYAREA WWW.YOUTUBE.COM/NWSBAYAREA
AREA FORECAST DISCUSSION
NWS PUEBLO CO
315 PM MST MON FEB 23 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 314 PM MST MON FEB 23 2015 AN UPR LOW OVR CA TODAY IS EXPECTED TO MOVE EASTWARD TONIGHT... MOVING INTO NORTH CENTRAL AZ BY 12Z TUE...AND THEN WEAKENING AND MOVING SOUTHEASTWARD THRU NM ON TUE. SNOW HAS CONTINUED FALLING OVER THE MTNS AND HIGH VALLEYS THIS AFTERNOON. IN THE SAN LUIS VALLEY THE SNOW HAS NOT BEEN WIDESPREAD AND IT FAIRLY SPOTTY AND WL CANCEL SNOW ADVISORY AT 3 PM. OVER THE SANGRE DE CRISTO MTNS THE SNOW IS ALSO BECOMING MORE SPOTTY...EXCEPT OVR THE FAR SRN AREAS NR THE NEW MEXICO BORDER. WL ALLOW THAT ADVISORY TO EXPIRE AT 3 PM. THE NAM AND HRRR SHOW PCPN CHANCE DECREASING RAPIDLY IN THE EVENING HOURS OVR MOST OF THE MTNS AND HIGH VALLEY AREAS. THE NAM KEEPS WIDESPREAD SNOW OVR THE ERN SAN JUANS EARLY IN THE EVENING. WEB CAMS SHOULD LITTLE IN THE WAY OF SNOWFALL CURRENTLY AT LXV AND MONARCH PASS...SO WL CANCEL THE WARNINGS FOR LAKE AND CHAFFEE COUNTIES AT 3 PM...ALONG WITH CANCELING WARNINGS FOR ZONES 64 AND 65...BUT WL LEAVE WARNINGS IN EFFECT UNTIL 5 PM FOR ZONES 66 AND 67. WL LEAVE THE WARNING FOR THE ERN SAN JUANS (ZONE 68) IN EFFECT UNTIL 06Z. ERN SAN JUANS COULD GET ANOTHER FEW INCHES IN THE EVENING HOURS...WITH LITTLE ADDITIONAL ACCUMULATION AFTER MIDNIGHT AS THE SNOW TAPERS OFF. BY 09Z THE NAM SHOWS DRY WX OVR THE ENTIRE FORECAST AREA...WITH DRY CONDITIONS THRU AT LEAST MIDMORNING TUE. THE NAM THEN SHOWS THE POTENTIAL FOR SOME LIGHT PCPN AGAIN OVR THE SW MTNS AS THE UPR LOW MOVES INTO NM. HOWEVER THE GFS HAS LIGHT PCPN CONTINUING OVR THE SW MTNS AND THE SANGRES THRU THE NIGHT AND THRU TUE. THE ECMWF IS SIMILAR TO THE GFS BUT DOES NOT SPREAD THE PCPN ON TUE QUITE AS FAR NORTH. HAVE DECIDED TO KEEP LOW POPS OVR THE SANGRES AND PORTIONS OF THE CENTRAL MTNS THRU TONIGHT AND TUE...WITH HIGHER POPS OVR THE SW MTNS DURING THIS SAME TIME-FRAME...BUT NOT EXPECTING ANYTHING MORE THAN SOME LIGHT ACCUMULATIONS. IT IS POSSIBLE FOR THE SAN LUIS VALLEY TO SEE SOME VERY LIGHT SNOW DEVELOP AGAIN AS LOW CLOUDS COVER MUCH OF THE AREA. TEMPS WL BE WARMER ON TUE...BUT THE SNOW COVER IN MANY LOCATIONS WL LIMIT THE AMOUNT OF WARMING AND SO WL STAY BELOW GUIDANCE IN MANY AREAS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 314 PM MST MON FEB 23 2015 ...ACTIVE AND COLD WEATHER PATTERN TO CONTINUE... MODELS IN GOOD AGREEMENT WITH ACTIVE WEATHER PERSISTING THROUGH THE EXTENDED PERIOD. SEVERAL DISTURBANCES WILL KEEP PERIODS OF MODERATE TO HEAVY SNOW GOING FOR MOST OF SOUTHERN COLORADO. TUESDAY NIGHT...AN UPPER LEVEL DISTURBANCE WILL BE EXITING THE DESERT SOUTHWEST INTO TEXAS EARLY TUESDAY NIGHT. LIGHT LINGERING SNOWFALL OVER THE SOUTHERN SAN JUANS SHOULD COME TO AN END BY MIDNIGHT. A SECONDARY DISTURBANCE WILL BE DROPPING SOUTH OUT OF THE NORTHERN ROCKIES LATE TUESDAY NIGHT WITH LIGHT SNOW DEVELOPING OVER THE CENTRAL MOUNTAINS BY WEDNESDAY MORNING. WEDNESDAY AND THURSDAY...THE SHORTWAVE OVER THE NORTHERN ROCKIES IS FORECAST TO STRENGTHEN AND DROP SOUTH ACROSS COLORADO THROUGH THIS PERIOD. THERE ARE A FEW SLIGHT MODEL DIFFERENCES WHICH COULD PLAY A ROLE IN HOW MUCH SNOW SOME AREAS SEE. SNOW WILL BE ON THE INCREASE OVER THE CENTRAL MOUNTAINS WEDNESDAY MORNING AND SPREAD SOUTH AND EAST INTO THE PALMER DIVIDE BY WEDNESDAY AFTERNOON. ACROSS THE PLAINS...A STRONG COLD FRONT IS FORECAST TO DROP SOUTH BY LATE WEDNESDAY AFTERNOON. FLOW BEHIND THE COLD FRONT IS FORECAST TO TRANSITION NORTHEASTERLY HELPING TO PRODUCE LOW LEVEL UPSLOPE FLOW AS THE UPPER DISTURBANCE DROPS ACROSS THE AREA. HEAVY SNOW IS LIKELY TO DEVELOP OVER THE EASTERN MOUNTAINS...DOWN INTO THE I-25 CORRIDOR WEDNESDAY EVENING AND CONTINUE INTO THURSDAY MORNING. SNOW TOTALS LOOK TO BE HIGHEST OVER THE CENTRAL MOUNTAINS WHERE ANOTHER FOOT OR MORE OF SNOW IS EXPECTED...WHILE THE LOWER ELEVATIONS ALONG THE I-25 CORRIDOR WILL SEE 2 TO 6 INCHES. LIGHT SNOW IS EXPECTED ACROSS ALL THE EASTERN PLAINS WITH 1 TO 3 INCHES POSSIBLE. THE MAIN MODEL DIFFERENCE IS WITH THE NAM WHICH KEEPS LOW AND MID LEVEL FLOW A BIT MORE NORTHERLY...WHICH WOULD LIMIT UPSLOPE EFFECTS AND SNOW TOTALS ALONG THE I-25 CORRIDOR. THIS WILL NEED TO BE MONITORED. THE HEAVIEST SNOW WILL COME TO AN END BY LATE THURSDAY MORNING...WITH LIGHT SNOW LIKELY LINGERING ACROSS THE AREA THROUGH THURSDAY NIGHT. TEMPERATURES WILL BE COLD WITH 30S FOR HIGHS ON WEDNESDAY...WITH 20S ON THURSDAY. FRIDAY...BROAD NORTHWEST FLOW WILL TRANSITION TO SOUTHWESTERLY FLOW AS THE NEXT UPPER LEVEL DISTURBANCE DROPS SOUTH ALONG THE WEST COAST. WEAK ENERGY MOVING ACROSS THE REGION WILL LIKELY KEEP LIGHT SNOW GOING OVER THE MOUNTAINS. TEMPERATURES WILL REMAIN COLD ACROSS THE PLAINS WITH 20S FOR HIGHS. SATURDAY THROUGH MONDAY...THE UPPER SYSTEM ALONG THE WEST COAST IS FORECAST TO STRENGTHEN AND SLOWLY DRIFT SOUTH INTO SOUTHERN CALIFORNIA BY EARLY NEXT WEEK. SOUTHWESTERLY FLOW WILL TAP INTO SUBTROPICAL MOISTURE AND SPREAD IT NORTHEASTWARD ACROSS COLORADO. THIS WILL SET THE STAGE FOR HEAVY SNOWFALL ALONG THE CONTINENTAL DIVIDE THROUGH THE WEEKEND...WITH THE HEAVIEST SNOWFALL OVER THE SAN JUAN RANGE. MODELS KEEP LIGHT SNOW ACROSS ALL OF SOUTHERN COLORADO THROUGH THE WEEKEND. COLD AIR WILL REMAIN IN PLACE WITH 30S FOR HIGHS ACROSS THE LOWER ELEVATIONS. MOZLEY && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 314 PM MST MON FEB 23 2015 KPUB IS EXPECTED TO HAVE VFR CONDITIONS TONIGHT AND TUESDAY. KALS SHOULD SEE VFR CONDITIONS IN THE EVENING HOURS UNLESS SOME SHOWERS ARE IN THE VCNTY WHICH COULD LEAD TO BRIEF MVFR CONDITIONS. THEN LATE TONIGHT KALS SHOULD SEE LOW CLOUDS AND FOG DEVELOP WITH IFR OR LIFR CONDITIONS INTO MIDMORNING TUE...AND THEN VFR CONDITIONS FOR THE LATE MORNING AND AFTERNOON. KCOS MAY STILL HAVE SOME VERY LIGHT SNOW IN THE VCNTY IN THE EARLY EVENING HOURS WITH MVFR OR IFR CONDITIONS...THEN BY LATE EVENING CONDITIONS ARE EXPECTED TO BECOME VFR AS SFC WINDS BECOME NW TO N. && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR COZ068. WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ066- 067. && $$ SHORT TERM...28 LONG TERM...MOZLEY AVIATION...28
AREA FORECAST DISCUSSION
NWS PUEBLO CO
304 PM MST MON FEB 23 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 303 PM MST MON FEB 23 2015 AN UPR LOW OVR CA TODAY IS EXPECTED TO MOVE EASTWARD TONIGHT... MOVING INTO NORTH CENTRAL AZ BY 12Z TUE...AND THEN WEAKENING AND MOVING SOUTHEASTWARD THRU NM ON TUE. SNOW HAS CONTINUED FALLING OVER THE MTNS AND HIGH VALLEYS THIS AFTERNOON. IN THE SAN LUIS VALLEY THE SNOW HAS NOT BEEN WIDESPREAD AND IT FAIRLY SPOTTY AND WL CANCEL SNOW ADVISORY AT 3 PM. OVER THE SANGRE DE CRISTO MTNS THE SNOW IS ALSO BECOMING MORE SPOTTY...EXCEPT OVR THE FAR SRN AREAS NR THE NEW MEXICO BORDER. WL ALLOW THAT ADVISORY TO EXPIRE AT 3 PM. THE NAM AND HRRR SHOW PCPN CHANCE DECREASING RAPIDLY IN THE EVENING HOURS OVR MOST OF THE MTNS AND HIGH VALLEY AREAS. THE NAM KEEPS WIDESPREAD SNOW OVR THE ERN SAN JUANS EARLY IN THE EVENING. WEB CAMS SHOULD LITTLE IN THE WAY OF SNOWFALL CURRENTLY AT LXV AND MONARCH PASS...SO WL CANCEL THE WARNINGS FOR LAKE AND CHAFFEE COUNTIES AT 3 PM...ALONG WITH CANCELING WARNINGS FOR ZONES 64 AND 65...BUT WL LEAVE WARNINGS IN EFFECT UNTIL 5 PM FOR ZONES 66 AND 67. WL LEAVE THE WARNING FOR THE ERN SAN JUANS (ZONE 68) IN EFFECT UNTIL 06Z. ERN SAN JUANS COULD GET ANOTHER FEW INCHES IN THE EVENING HOURS...WITH LITTLE ADDITIONAL ACCUMULATION AFTER MIDNIGHT AS THE SNOW TAPERS OFF. BY 09Z THE NAM SHOWS DRY WX OVR THE ENTIRE FORECAST AREA...WITH DRY CONDITIONS THRU AT LEAST MIDMORNING TUE. THE NAM THEN SHOWS THE POTENTIAL FOR SOME LIGHT PCPN AGAIN OVR THE SW MTNS AS THE UPR LOW MOVES INTO NM. HOWEVER THE GFS HAS LIGHT PCPN CONTINUING OVR THE SW MTNS AND THE SANGRES THRU THE NIGHT AND THRU TUE. THE ECMWF IS SIMILAR TO THE GFS BUT DOES NOT SPREAD THE PCPN ON TUE QUITE AS FAR NORTH. HAVE DECIDED TO KEEP LOW POPS OVR THE SANGRES AND PORTIONS OF THE CENTRAL MTNS THRU TONIGHT AND TUE...WITH HIGHER POPS OVR THE SW MTNS DURING THIS SAME TIME-FRAME...BUT NOT EXPECTING ANYTHING MORE THAN SOME LIGHT ACCUMULATIONS. IT IS POSSIBLE FOR THE SAN LUIS VALLEY TO SEE SOME VERY LIGHT SNOW DEVELOP AGAIN AS LOW CLOUDS COVER MUCH OF THE AREA. TEMPS WL BE WARMER ON TUE...BUT THE SNOW COVER IN MANY LOCATIONS WL LIMIT THE AMOUNT OF WARMING AND SO WL STAY BELOW GUIDANCE IN MANY AREAS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 303 PM MST MON FEB 23 2015 ...ACTIVE AND COLD WEATHER PATTERN TO CONTINUE... MODELS IN GOOD AGREEMENT WITH ACTIVE WEATHER PERSISTING THROUGH THE EXTENDED PERIOD. SEVERAL DISTURBANCES WILL KEEP PERIODS OF MODERATE TO HEAVY SNOW GOING FOR MOST OF SOUTHERN COLORADO. TUESDAY NIGHT...AN UPPER LEVEL DISTURBANCE WILL BE EXITING THE DESERT SOUTHWEST INTO TEXAS EARLY TUESDAY NIGHT. LIGHT LINGERING SNOWFALL OVER THE SOUTHERN SAN JUANS SHOULD COME TO AN END BY MIDNIGHT. A SECONDARY DISTURBANCE WILL BE DROPPING SOUTH OUT OF THE NORTHERN ROCKIES LATE TUESDAY NIGHT WITH LIGHT SNOW DEVELOPING OVER THE CENTRAL MOUNTAINS BY WEDNESDAY MORNING. WEDNESDAY AND THURSDAY...THE SHORTWAVE OVER THE NORTHERN ROCKIES IS FORECAST TO STRENGTHEN AND DROP SOUTH ACROSS COLORADO THROUGH THIS PERIOD. THERE ARE A FEW SLIGHT MODEL DIFFERENCES WHICH COULD PLAY A ROLE IN HOW MUCH SNOW SOME AREAS SEE. SNOW WILL BE ON THE INCREASE OVER THE CENTRAL MOUNTAINS WEDNESDAY MORNING AND SPREAD SOUTH AND EAST INTO THE PALMER DIVIDE BY WEDNESDAY AFTERNOON. ACROSS THE PLAINS...A STRONG COLD FRONT IS FORECAST TO DROP SOUTH BY LATE WEDNESDAY AFTERNOON. FLOW BEHIND THE COLD FRONT IS FORECAST TO TRANSITION NORTHEASTERLY HELPING TO PRODUCE LOW LEVEL UPSLOPE FLOW AS THE UPPER DISTURBANCE DROPS ACROSS THE AREA. HEAVY SNOW IS LIKELY TO DEVELOP OVER THE EASTERN MOUNTAINS...DOWN INTO THE I-25 CORRIDOR WEDNESDAY EVENING AND CONTINUE INTO THURSDAY MORNING. SNOW TOTALS LOOK TO BE HIGHEST OVER THE CENTRAL MOUNTAINS WHERE ANOTHER FOOT OR MORE OF SNOW IS EXPECTED...WHILE THE LOWER ELEVATIONS ALONG THE I-25 CORRIDOR WILL SEE 2 TO 6 INCHES. LIGHT SNOW IS EXPECTED ACROSS ALL THE EASTERN PLAINS WITH 1 TO 3 INCHES POSSIBLE. THE MAIN MODEL DIFFERENCE IS WITH THE NAM WHICH KEEPS LOW AND MID LEVEL FLOW A BIT MORE NORTHERLY...WHICH WOULD LIMIT UPSLOPE EFFECTS AND SNOW TOTALS ALONG THE I-25 CORRIDOR. THIS WILL NEED TO BE MONITORED. THE HEAVIEST SNOW WILL COME TO AN END BY LATE THURSDAY MORNING...WITH LIGHT SNOW LIKELY LINGERING ACROSS THE AREA THROUGH THURSDAY NIGHT. TEMPERATURES WILL BE COLD WITH 30S FOR HIGHS ON WEDNESDAY...WITH 20S ON THURSDAY. FRIDAY...BROAD NORTHWEST FLOW WILL TRANSITION TO SOUTHWESTERLY FLOW AS THE NEXT UPPER LEVEL DISTURBANCE DROPS SOUTH ALONG THE WEST COAST. WEAK ENERGY MOVING ACROSS THE REGION WILL LIKELY KEEP LIGHT SNOW GOING OVER THE MOUNTAINS. TEMPERATURES WILL REMAIN COLD ACROSS THE PLAINS WITH 20S FOR HIGHS. SATURDAY THROUGH MONDAY...THE UPPER SYSTEM ALONG THE WEST COAST IS FORECAST TO STRENGTHEN AND SLOWLY DRIFT SOUTH INTO SOUTHERN CALIFORNIA BY EARLY NEXT WEEK. SOUTHWESTERLY FLOW WILL TAP INTO SUBTROPICAL MOISTURE AND SPREAD IT NORTHEASTWARD ACROSS COLORADO. THIS WILL SET THE STAGE FOR HEAVY SNOWFALL ALONG THE CONTINENTAL DIVIDE THROUGH THE WEEKEND...WITH THE HEAVIEST SNOWFALL OVER THE SAN JUAN RANGE. MODELS KEEP LIGHT SNOW ACROSS ALL OF SOUTHERN COLORADO THROUGH THE WEEKEND. COLD AIR WILL REMAIN IN PLACE WITH 30S FOR HIGHS ACROSS THE LOWER ELEVATIONS. MOZLEY && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 303 PM MST MON FEB 23 2015 KPUB IS EXPECTED TO HAVE VFR CONDITIONS TONIGHT AND TUESDAY. KALS SHOULD SEE VFR CONDITIONS IN THE EVENING HOURS UNLESS SOME SHOWERS ARE IN THE VCNTY WHICH COULD LEAD TO BRIEF MVFR CONDITIONS. THEN LATE TONIGHT KALS SHOULD SEE LOW CLOUDS AND FOG DEVELOP WITH IFR OR LIFR CONDITIONS INTO MIDMORNING TUE...AND THEN VFR CONDITIONS FOR THE LATE MORNING AND AFTERNOON. KCOS MAY STILL HAVE SOME VERY LIGHT SNOW IN THE VCNTY IN THE EARLY EVENING HOURS WITH MVFR OR IFR CONDITIONS...THEN BY LATE EVENING CONDITIONS ARE EXPECTED TO BECOME VFR AS SFC WINDS BECOME NW TO N. && .PUB WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR COZ068. WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ060- 066-067. && $$ SHORT TERM...28 LONG TERM...MOZLEY AVIATION...28
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1219 PM MST MON FEB 23 2015 .UPDATE... ISSUED AT 1134 AM MST MON FEB 23 2015 ALLOWED THE WINTER ADVISORY FOR THE GRAND VALLEY AND THE WINTER STORM WARNINGS FOR THE DEBEQUE-SILT CORRIDOR AND CENTRAL CO RIVER VALLEY TO EXPIRE AT NOON. LIGHT SNOW WILL HANG AROUND IN PLACES ALONG THE I-70 CORRIDOR THIS AFTERNOON BUT AMOUNTS ARE EXPECTED TO BE AN INCH OR LESS. TEMPS NEAR OR BELOW FREEZING COULD ALSO KEEP UNTREATED ROADS/SIDEWALKS SLICK. ALSO LET THE WINTER STORM WARNINGS EXPIRE FOR THE ROAN/TAVAPUTS PLATEAU AND THE FLAT TOPS/WHITE RIVER PLATEAU AS OVERALL FORCING SLOWLY SHIFTS SOUTHWARD. SNOW SHOULD REMAIN WIDESPREAD ACROSS SE UT AND SW CO THROUGH THE AFTERNOON...BUT MODELS INDICATING A LULL IN THE ACTIVITY OR JUST SOME LIGHT SNOW THIS EVENING. ANOTHER BURST OF A COUPLE INCHES OF SNOW THEN EXPECTED TOWARD SUNRISE FOR FAR SE UT AND SW CO AS THE MAIN UPPER LOW CURRENTLY OVER CENTRAL CA MOVES ACROSS NRN AZ. UPDATE ISSUED AT 1013 AM MST MON FEB 23 2015 SNOW REMAINED WIDESPREAD ACROSS SW CO THIS MORNING...PRETTY MUCH FROM GRAND JCT AND ASPEN SOUTH. OBSERVATIONS INDICATING THE HEAVIER SNOW FROM ABOUT MONTROSE/PARADOX VALLEY SOUTH. SNOW ALSO NOTED ACROSS MUCH OF SE UT. THIS UNDER A BROAD AREA OF UPPER DIVERGENCE/ LOWER (MOISTURE)CONVERGENCE PLUS ISENTROPIC UPGLIDE AND A MOIST DENDRITIC SNOW GROWTH ZONE. EARLY LOOK AT THIS MORNING`S MODELS SHOW THE HEAVIER SNOW BAND SLOWLY SHIFTNIG SOUTH WITH SOME REDUCTION IN UPPER LEVEL SUPPORT AS THE UPPER JET ACROSS NRN AZ AND NRN NM PROGRESSES EASTWARD. WINTER STORM WARNINGS CONTINUE FOR SE UT AND SW CO. STILL ASSESSING WHETHER OR NOT TO EXTEND THE HIGHLIGHTS INTO TUE FOR AT LEAST THE AREAS FROM THE ABAJOS AND SAN JUANS SOUTH. LIGHT SNOW IN THE GRAND VALLEY THIS MORNING BELIEVED TO BE MAINLY DUE TO MOISTURE IN SSW FLOW OVERRUNNING COLD AIR TRAPPED IN THE VALLEY. NAM12 AND HIGH RESOLUTION RAP MODELS SUGGEST THIS MOIST OVERRUNNING DECREASES FOR THE GRAND VALLEY THIS AFTERNOON AS FLOW ALOFT BEGINS TO TAKE ON A MORE NORTHERLY TACK. THESE MODELS ALSO SHOW ONLY LIGHT SNOW ACCUMS THERE THIS AFTERNOON. WHETHER TO EXTEND THE ADVISORY FOR THE GRAND INTO THIS AFTERNOON WILL PROBABLY BE A LAST- MINUTE CALL AND SOMEWHAT DEPENDENT ON HOW MUCH TEMPS WARM TO EASE THE THREAT OF ICY ROADS AND SIDEWALKS. BELIEVE THE NOONTIME EXPIRATION OF THE WINTER HIGHLIGHT FOR THE DEBEQUE TO SILT CORRIDOR AND THE CENTRAL CO RIVER VALLEY STILL LOOKS ON TRACK. .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 519 AM MST MON FEB 23 2015 SNOWFALL CONTINUES ACROSS MOST OF THE SOUTHERN HALF OF THE FORECAST AREA...AND NORTHWARD ACROSS THE I-70 CORRIDOR EARLY THIS MORNING. ALREADY SIGNIFICANT AMOUNTS HAVE FALLEN FROM THE UNCOMPAHGRE RIVER BASIN SOUTH TO THE NM BORDER...WITH MORE EXPECTED THROUGH TODAY. SNOW IN THE CENTRAL VALLEYS FROM MOAB TO GRAND JUNCTION TO EAGLE HAS BEEN MORE ON THE LIGHT SIDE. WILL DROP THE ADVISORY FOR MOAB AND THE GRAND FLAT WITH THIS PACKAGE AS THAT ZONE HAS RECEIVED VERY LITTLE SNOW...WITH NOT MUCH MORE EXPECTED. HOWEVER WILL KEEP THE HIGHLIGHTS GOING FOR THE COLORADO I-70 CORRIDOR AS THOSE ZONES HAVE RECEIVED ENOUGH TO AFFECT TRAVEL...AND MODEST AMOUNTS ARE STILL EXPECTED THROUGH THE MORNING. HAVE ALSO OPTED TO END THE WARNINGS EARLY FOR THE COLORADO TAVAPUTS AND THE FLATTOPS...TO COINCIDE WITH THE END TIMING OF THESE I-70 CORRIDOR VALLEY ZONES WHICH EXPIRE AT NOON. ON THE FLIP SIDE HAVE EXTENDED THE WARNING FOR UT ZONE 29 UNTIL MIDNIGHT TO MATCH UP BETTER WITH THE HIGHLIGHTS FOR OTHER SOUTHEAST UT AND SOUTHWEST CO ZONES. ALL OF SOUTHEAST UT AND SOUTHWEST CO FROM AROUND THE LA SAL MOUNTAINS EAST TO THE SOUTHERN SLOPES OF THE GRAND MESA AND THE WEST ELKS...AND SOUTHWARD TO THE NM/AZ BORDERS WILL CONTINUE TO BE UNDER THE GUN TODAY AS A MOIST AND UNSTABLE AIR MASS CONTINUES TO FLOW INTO THE REGION. A CONVERGENT ZONE HAS DEVELOPED FROM AROUND BLANDING TO MONTROSE AND WILL PERSIST MORE OR LESS THROUGH THE DAY. THIS IS ALL THE RESULT OF A LOW PRESSURE CENTER THAT WILL CLOSE OFF OVER CENTRAL CALIFORNIA TODAY...THEN MOVE INTO NORTHWEST AZ TONIGHT. AS A RESULT A DEFORMATION ZONE WILL DEVELOP ACROSS THE SOUTHERN PORTION OF OUR AREA AND KEEP MODERATE TO HEAVY SNOW INTO THE EVENING OVER THE SOUTHERN ZONES. ENOUGH COOLING WILL HAVE OCCURRED BY THIS AFTERNOON...THAT I DO NOT EXPECT SNOW TO CHANGE OVER...OR EVEN MIX WITH TO RAIN EXCEPT POSSIBLY FOR BRIEF PERIODS IN THE LOWEST SOUTHERN VALLEYS. THE LOW WILL THEN MOVE INTO CENTRAL/SOUTHERN NEW MEXICO ON TUE WITH PRECIPITATION PERSISTING INTO THE AFTERNOON OVER THE SOUTHERN EDGE. HOWEVER SNOW INTENSITY LATE TONIGHT THROUGH TUE IS MOSTLY EXPECTED TO BE LIGHT...ESPECIALLY WHEN COMPARED TO THE AMOUNTS THIS STORM HAS ALREADY PRODUCED. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 519 AM MST MON FEB 23 2015 SNOW FINALLY DIMINISHES ACROSS THE SOUTH AS THE LATEST STORM IS FORCED TO THE SOUTHEAST TUESDAY NIGHT. HOWEVER...EXPECT SOME LIGHT SNOW TO BEGIN ACROSS THE NORTHERN COLORADO MOUNTAINS LATER IN THE NIGHT AS MOISTURE AHEAD OF AN APPROACHING SHORTWAVE TROUGH TO THE NORTHWEST SWEEPS OVER THE AREA. EXPECT SNOW TO INCREASE AND SPREAD INTO THE SOUTHERN MOUNTAINS AND ADJACENT VALLEYS WEDNESDAY AND WEDNESDAY NIGHT AS THE SHORTWAVE TROUGH PASSES SOUTHEASTWARD ACROSS THE AREA. IN FACT...A SERIES OF WAVES WILL PASS THROUGH THE AREA DURING THE REMAINDER OF THE WEEK...MAINLY IMPACTING THE COLORADO DIVIDE MOUNTAINS. A BIT DIFFICULT TO TIME THESE DISTURBANCES THIS FAR OUT BUT GOES WITHOUT SAYING THAT THE PATTERN HAS SHIFTED TO A MORE PROGRESSIVE...WETTER...AND COOLER REGIME. IN FACT...FOR THOSE ALREADY DIGGING OUT ACROSS SOUTHEAST UTAH AND SOUTHWEST COLORADO...MODELS ARE HINTING AT THE POTENTIAL FOR ANOTHER SIGNIFICANT SNOW EVENT THIS WEEKEND. DETAILS A BIT SKETCHY AT THIS POINT AS GFS AND EC NOT ENTIRELY ON THE SAME PAGE. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 519 AM MST MON FEB 23 2015 SNOWFALL CONTINUES ACROSS MOST OF THE SOUTHERN HALF OF THE FORECAST AREA...AND NORTHWARD ACROSS THE I-70 CORRIDOR EARLY THIS MORNING. ALREADY SIGNIFICANT AMOUNTS HAVE FALLEN FROM THE UNCOMPAHGRE RIVER BASIN SOUTH TO THE NM BORDER...WITH MORE EXPECTED THROUGH TODAY. SNOW IN THE CENTRAL VALLEYS FROM MOAB TO GRAND JUNCTION TO EAGLE HAS BEEN MORE ON THE LIGHT SIDE. WILL DROP THE ADVISORY FOR MOAB AND THE GRAND FLAT WITH THIS PACKAGE AS THAT ZONE HAS RECEIVED VERY LITTLE SNOW...WITH NOT MUCH MORE EXPECTED. HOWEVER WILL KEEP THE HIGHLIGHTS GOING FOR THE COLORADO I-70 CORRIDOR AS THOSE ZONES HAVE RECEIVED ENOUGH TO AFFECT TRAVEL...AND MODEST AMOUNTS ARE STILL EXPECTED THROUGH THE MORNING. HAVE ALSO OPTED TO END THE WARNINGS EARLY FOR THE COLORADO TAVAPUTS AND THE FLATTOPS...TO COINCIDE WITH THE END TIMING OF THESE I-70 CORRIDOR VALLEY ZONES WHICH EXPIRE AT NOON. ON THE FLIP SIDE HAVE EXTENDED THE WARNING FOR UT ZONE 29 UNTIL MIDNIGHT TO MATCH UP BETTER WITH THE HIGHLIGHTS FOR OTHER SOUTHEAST UT AND SOUTHWEST CO ZONES. ALL OF SOUTHEAST UT AND SOUTHWEST CO FROM AROUND THE LA SAL MOUNTAINS EAST TO THE SOUTHERN SLOPES OF THE GRAND MESA AND THE WEST ELKS...AND SOUTHWARD TO THE NM/AZ BORDERS WILL CONTINUE TO BE UNDER THE GUN TODAY AS A MOIST AND UNSTABLE AIR MASS CONTINUES TO FLOW INTO THE REGION. A CONVERGENT ZONE HAS DEVELOPED FROM AROUND BLANDING TO MONTROSE AND WILL PERSIST MORE OR LESS THROUGH THE DAY. THIS IS ALL THE RESULT OF A LOW PRESSURE CENTER THAT WILL CLOSE OFF OVER CENTRAL CALIFORNIA TODAY...THEN MOVE INTO NORTHWEST AZ TONIGHT. AS A RESULT A DEFORMATION ZONE WILL DEVELOP ACROSS THE SOUTHERN PORTION OF OUR AREA AND KEEP MODERATE TO HEAVY SNOW INTO THE EVENING OVER THE SOUTHERN ZONES. ENOUGH COOLING WILL HAVE OCCURRED BY THIS AFTERNOON...THAT I DO NOT EXPECT SNOW TO CHANGE OVER...OR EVEN MIX WITH TO RAIN EXCEPT POSSIBLY FOR BRIEF PERIODS IN THE LOWEST SOUTHERN VALLEYS. THE LOW WILL THEN MOVE INTO CENTRAL/SOUTHERN NEW MEXICO ON TUE WITH PRECIPITATION PERSISTING INTO THE AFTERNOON OVER THE SOUTHERN EDGE. HOWEVER SNOW INTENSITY LATE TONIGHT THROUGH TUE IS MOSTLY EXPECTED TO BE LIGHT...ESPECIALLY WHEN COMPARED TO THE AMOUNTS THIS STORM HAS ALREADY PRODUCED. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 519 AM MST MON FEB 23 2015 SNOW FINALLY DIMINISHES ACROSS THE SOUTH AS THE LATEST STORM IS FORCED TO THE SOUTHEAST TUESDAY NIGHT. HOWEVER...EXPECT SOME LIGHT SNOW TO BEGIN ACROSS THE NORTHERN COLORADO MOUNTAINS LATER IN THE NIGHT AS MOISTURE AHEAD OF AN APPROACHING SHORTWAVE TROUGH TO THE NORTHWEST SWEEPS OVER THE AREA. EXPECT SNOW TO INCREASE AND SPREAD INTO THE SOUTHERN MOUNTAINS AND ADJACENT VALLEYS WEDNESDAY AND WEDNESDAY NIGHT AS THE SHORTWAVE TROUGH PASSES SOUTHEASTWARD ACROSS THE AREA. IN FACT...A SERIES OF WAVES WILL PASS THROUGH THE AREA DURING THE REMAINDER OF THE WEEK...MAINLY IMPACTING THE COLORADO DIVIDE MOUNTAINS. A BIT DIFFICULT TO TIME THESE DISTURBANCES THIS FAR OUT BUT GOES WITHOUT SAYING THAT THE PATTERN HAS SHIFTED TO A MORE PROGRESSIVE...WETTER...AND COOLER REGIME. IN FACT...FOR THOSE ALREADY DIGGING OUT ACROSS SOUTHEAST UTAH AND SOUTHWEST COLORADO...MODELS ARE HINTING AT THE POTENTIAL FOR ANOTHER SIGNIFICANT SNOW EVENT THIS WEEKEND. DETAILS A BIT SKETCHY AT THIS POINT AS GFS AND EC NOT ENTIRELY ON THE SAME PAGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1013 AM MST MON FEB 23 2015 THIS WINTER STORM IS SLOWLY WINDING DOWN BUT PLENTY OF AVIATION CONCERNS WILL CONTINUE OVER THE NEXT 24 HOURS. SNOW LOOKS TO CONTINUE ACROSS SOUTHWEST COLORADO TO SOUTHEAST UTAH...WITH MVFR/IFR IMPACTS TO THE SOUTHERN FORECAST TERMINALS A HIGH PROBABILITY TO CONTINUE THROUGH TUESDAY. IMPROVEMENT ALONG THE WESTERN INTERSTATE 70 CORRIDOR SHOULD OCCUR AFTER 20Z WITH IFR CONDITIONS HANGING IN AT CNY AND GJT LATE THIS MORNING AND VFR IN THE COLORADO AND EAGLE VALLEYS TO THE EAST. OBSCURATION OF THE TERRAIN WILL PERSIST OVER THE NEXT 24 HOURS AS WELL. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ009>012- 014-017>023. UT...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR UTZ022-029. WINTER STORM WARNING UNTIL 6 AM MST TUESDAY FOR UTZ028. && $$ UPDATE...JAD SHORT TERM...EH LONG TERM...NL AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1015 AM MST MON FEB 23 2015 .UPDATE... ISSUED AT 1013 AM MST MON FEB 23 2015 SNOW REMAINED WIDESPREAD ACROSS SW CO THIS MORNING...PRETTY MUCH FROM GRAND JCT AND ASPEN SOUTH. OBSERVATIONS INDICATING THE HEAVIER SNOW FROM ABOUT MONTROSE/PARADOX VALLEY SOUTH. SNOW ALSO NOTED ACROSS MUCH OF SE UT. THIS UNDER A BROAD AREA OF UPPER DIVERGENCE/ LOWER (MOISTURE)CONVERGENCE PLUS ISENTROPIC UPGLIDE AND A MOIST DENDRITIC SNOW GROWTH ZONE. EARLY LOOK AT THIS MORNING`S MODELS SHOW THE HEAVIER SNOW BAND SLOWLY SHIFTNIG SOUTH WITH SOME REDUCTION IN UPPER LEVEL SUPPORT AS THE UPPER JET ACROSS NRN AZ AND NRN NM PROGRESSES EASTWARD. WINTER STORM WARNINGS CONTINUE FOR SE UT AND SW CO. STILL ASSESSING WHETHER OR NOT TO EXTEND THE HIGHLIGHTS INTO TUE FOR AT LEAST THE AREAS FROM THE ABAJOS AND SAN JUANS SOUTH. LIGHT SNOW IN THE GRAND VALLEY THIS MORNING BELIEVED TO BE MAINLY DUE TO MOISTURE IN SSW FLOW OVERRUNNING COLD AIR TRAPPED IN THE VALLEY. NAM12 AND HIGH RESOLUTION RAP MODELS SUGGEST THIS MOIST OVERRUNNING DECREASES FOR THE GRAND VALLEY THIS AFTERNOON AS FLOW ALOFT BEGINS TO TAKE ON A MORE NORTHERLY TACK. THESE MODELS ALSO SHOW ONLY LIGHT SNOW ACCUMS THERE THIS AFTERNOON. WHETHER TO EXTEND THE ADVISORY FOR THE GRAND INTO THIS AFTERNOON WILL PROBABLY BE A LAST- MINUTE CALL AND SOMEWHAT DEPENDENT ON HOW MUCH TEMPS WARM TO EASE THE THREAT OF ICY ROADS AND SIDEWALKS. BELIEVE THE NOONTIME EXPIRATION OF THE WINTER HIGHLIGHT FOR THE DEBEQUE TO SILT CORRIDOR AND THE CENTRAL CO RIVER VALLEY STILL LOOKS ON TRACK. .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 519 AM MST MON FEB 23 2015 SNOWFALL CONTINUES ACROSS MOST OF THE SOUTHERN HALF OF THE FORECAST AREA...AND NORTHWARD ACROSS THE I-70 CORRIDOR EARLY THIS MORNING. ALREADY SIGNIFICANT AMOUNTS HAVE FALLEN FROM THE UNCOMPAHGRE RIVER BASIN SOUTH TO THE NM BORDER...WITH MORE EXPECTED THROUGH TODAY. SNOW IN THE CENTRAL VALLEYS FROM MOAB TO GRAND JUNCTION TO EAGLE HAS BEEN MORE ON THE LIGHT SIDE. WILL DROP THE ADVISORY FOR MOAB AND THE GRAND FLAT WITH THIS PACKAGE AS THAT ZONE HAS RECEIVED VERY LITTLE SNOW...WITH NOT MUCH MORE EXPECTED. HOWEVER WILL KEEP THE HIGHLIGHTS GOING FOR THE COLORADO I-70 CORRIDOR AS THOSE ZONES HAVE RECEIVED ENOUGH TO AFFECT TRAVEL...AND MODEST AMOUNTS ARE STILL EXPECTED THROUGH THE MORNING. HAVE ALSO OPTED TO END THE WARNINGS EARLY FOR THE COLORADO TAVAPUTS AND THE FLATTOPS...TO COINCIDE WITH THE END TIMING OF THESE I-70 CORRIDOR VALLEY ZONES WHICH EXPIRE AT NOON. ON THE FLIP SIDE HAVE EXTENDED THE WARNING FOR UT ZONE 29 UNTIL MIDNIGHT TO MATCH UP BETTER WITH THE HIGHLIGHTS FOR OTHER SOUTHEAST UT AND SOUTHWEST CO ZONES. ALL OF SOUTHEAST UT AND SOUTHWEST CO FROM AROUND THE LA SAL MOUNTAINS EAST TO THE SOUTHERN SLOPES OF THE GRAND MESA AND THE WEST ELKS...AND SOUTHWARD TO THE NM/AZ BORDERS WILL CONTINUE TO BE UNDER THE GUN TODAY AS A MOIST AND UNSTABLE AIR MASS CONTINUES TO FLOW INTO THE REGION. A CONVERGENT ZONE HAS DEVELOPED FROM AROUND BLANDING TO MONTROSE AND WILL PERSIST MORE OR LESS THROUGH THE DAY. THIS IS ALL THE RESULT OF A LOW PRESSURE CENTER THAT WILL CLOSE OFF OVER CENTRAL CALIFORNIA TODAY...THEN MOVE INTO NORTHWEST AZ TONIGHT. AS A RESULT A DEFORMATION ZONE WILL DEVELOP ACROSS THE SOUTHERN PORTION OF OUR AREA AND KEEP MODERATE TO HEAVY SNOW INTO THE EVENING OVER THE SOUTHERN ZONES. ENOUGH COOLING WILL HAVE OCCURRED BY THIS AFTERNOON...THAT I DO NOT EXPECT SNOW TO CHANGE OVER...OR EVEN MIX WITH TO RAIN EXCEPT POSSIBLY FOR BRIEF PERIODS IN THE LOWEST SOUTHERN VALLEYS. THE LOW WILL THEN MOVE INTO CENTRAL/SOUTHERN NEW MEXICO ON TUE WITH PRECIPITATION PERSISTING INTO THE AFTERNOON OVER THE SOUTHERN EDGE. HOWEVER SNOW INTENSITY LATE TONIGHT THROUGH TUE IS MOSTLY EXPECTED TO BE LIGHT...ESPECIALLY WHEN COMPARED TO THE AMOUNTS THIS STORM HAS ALREADY PRODUCED. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 519 AM MST MON FEB 23 2015 SNOW FINALLY DIMINISHES ACROSS THE SOUTH AS THE LATEST STORM IS FORCED TO THE SOUTHEAST TUESDAY NIGHT. HOWEVER...EXPECT SOME LIGHT SNOW TO BEGIN ACROSS THE NORTHERN COLORADO MOUNTAINS LATER IN THE NIGHT AS MOISTURE AHEAD OF AN APPROACHING SHORTWAVE TROUGH TO THE NORTHWEST SWEEPS OVER THE AREA. EXPECT SNOW TO INCREASE AND SPREAD INTO THE SOUTHERN MOUNTAINS AND ADJACENT VALLEYS WEDNESDAY AND WEDNESDAY NIGHT AS THE SHORTWAVE TROUGH PASSES SOUTHEASTWARD ACROSS THE AREA. IN FACT...A SERIES OF WAVES WILL PASS THROUGH THE AREA DURING THE REMAINDER OF THE WEEK...MAINLY IMPACTING THE COLORADO DIVIDE MOUNTAINS. A BIT DIFFICULT TO TIME THESE DISTURBANCES THIS FAR OUT BUT GOES WITHOUT SAYING THAT THE PATTERN HAS SHIFTED TO A MORE PROGRESSIVE...WETTER...AND COOLER REGIME. IN FACT...FOR THOSE ALREADY DIGGING OUT ACROSS SOUTHEAST UTAH AND SOUTHWEST COLORADO...MODELS ARE HINTING AT THE POTENTIAL FOR ANOTHER SIGNIFICANT SNOW EVENT THIS WEEKEND. DETAILS A BIT SKETCHY AT THIS POINT AS GFS AND EC NOT ENTIRELY ON THE SAME PAGE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1013 AM MST MON FEB 23 2015 THIS WINTER STORM IS SLOWLY WINDING DOWN BUT PLENTY OF AVIATION CONCERNS WILL CONTINUE OVER THE NEXT 24 HOURS. SNOW LOOKS TO CONTINUE ACROSS SOUTHWEST COLORADO TO SOUTHEAST UTAH...WITH MVFR/IFR IMPACTS TO THE SOUTHERN FORECAST TERMINALS A HIGH PROBABILITY TO CONTINUE THROUGH TUESDAY. IMPROVEMENT ALONG THE WESTERN INTERSTATE 70 CORRIDOR SHOULD OCCUR AFTER 20Z WITH IFR CONDITIONS HANGING IN AT CNY AND GJT LATE THIS MORNING AND VFR IN THE COLORADO AND EAGLE VALLEYS TO THE EAST. OBSCURATION OF THE TERRAIN WILL PERSIST OVER THE NEXT 24 HOURS AS WELL. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ009>012- 014-017>023. WINTER STORM WARNING UNTIL NOON MST TODAY FOR COZ003-007-008-013. WINTER WEATHER ADVISORY UNTIL NOON MST TODAY FOR COZ006. UT...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR UTZ022-029. WINTER STORM WARNING UNTIL 6 AM MST TUESDAY FOR UTZ028. && $$ SHORT TERM...EH LONG TERM...NL AVIATION...TGJT
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
100 PM CST MON FEB 23 2015 .AVIATION... FOR THE 23/18Z TAFS...WINTRY MIX OF PRECIPITATION WILL CONTINUE TO AFFECT OUR AREA TERMINALS THROUGH THE FIRST HALF OF THE TAF PERIOD EXCEPT LFK WHERE IT APPEARS WE MAY STAY WITH JUST LIGHT RAIN UNTIL THE OVERNIGHT HOURS. CIGS/VSBYS VARY WIDELY BUT ARE MOSTLY MVFR/IFR AND WILL REMAIN SO THROUGH THE TAF PERIOD. PRECIPITATION WILL TAPER OFF FROM WEST TO EAST THROUGH THE EVENING AND OVERNIGHT HOURS BUT CIGS WILL STILL REMAIN MOSTLY IFR. WINDS WILL MAINTAIN A NORTHERLY COMPONENT AND BEGIN TO DECREASE AFTER 24/00Z TO AROUND 5 KTS. /19/ && .PREV DISCUSSION... /ISSUED 1047 AM CST MON FEB 23 2015/ DISCUSSION... FREEZING LINE CURRENTLY ALONG THE INTERSTATE 20 CORRIDOR FROM JACKSONVILLE TEXAS TO MONROE LOUISIANA. PRECIPITATION ALONG AND NORTH OF INTERSTATE 20 IN THE FORM OF SNOW ACROSS SOUTHEAST OKLAHOMA...AND A MIX OF SLEET/FREEZING RAIN/RAIN ELSEWHERE. TEMPERATURES CONTINUING TO FALL AREAWIDE. LOOKS LIKE THIS PUSH OF PRECIPITATION MAY BE THE MAIN EVENT. HRRR AND GFS MODELS TEND TO SUGGEST A SECOND SURGE OF MOISTURE COMING UP FROM SOUTHEAST TEXAS LATER THIS AFTERNOON...WHILE NAM REMAINS THE OUTLIER WITH PRECIPITATION CONTINUING ACROSS THE SOUTHEAST OKLAHOMA AND SOUTHERN ARKANSAS. FOR THIS UPDATE...WILL MAINTAIN WARNINGS AND ADVISORIES AS IS. ONLY CHANGE WAS TO DECREASE POPS ACROSS DEEP EAST TEXAS AND WEST CENTRAL LOUISIANA BASED ON CURRENT RADAR TRENDS. /05/ && .PRELIMINARY POINT TEMPS/POPS... SHV 27 38 34 41 30 / 60 30 40 60 10 MLU 27 37 34 39 29 / 60 30 40 60 10 DEQ 24 37 30 41 29 / 50 20 20 50 10 TXK 26 37 31 41 28 / 50 20 20 60 10 ELD 24 38 31 40 27 / 60 20 20 60 10 TYR 27 37 33 41 32 / 60 20 40 60 10 GGG 28 39 33 41 31 / 60 20 40 60 10 LFK 29 41 34 41 33 / 60 30 40 60 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: ARZ070>072. WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: ARZ050-051-059>061-073. LA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: LAZ001>003. WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: LAZ004>006-010>014-017>022. OK...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: OKZ077. TX...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: TXZ096-097-108>112-124>126-136>138. WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: TXZ149>153-165>167. && $$ 19
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1047 AM CST MON FEB 23 2015 .DISCUSSION... FREEZING LINE CURRENTLY ALONG THE INTERSTATE 20 CORRIDOR FROM JACKSONVILLE TEXAS TO MONROE LOUISIANA. PRECIPITATION ALONG AND NORTH OF INTERSTATE 20 IN THE FORM OF SNOW ACROSS SOUTHEAST OKLAHOMA...AND A MIX OF SLEET/FREEZING RAIN/RAIN ELSEWHERE. TEMPERATURES CONTINUING TO FALL AREAWIDE. LOOKS LIKE THIS PUSH OF PRECIPITATION MAY BE THE MAIN EVENT. HRRR AND GFS MODELS TEND TO SUGGEST A SECOND SURGE OF MOISTURE COMING UP FROM SOUTHEAST TEXAS LATER THIS AFTERNOON...WHILE NAM REMAINS THE OUTLIER WITH PRECIPITATION CONTINUING ACROSS THE SOUTHEAST OKLAHOMA AND SOUTHERN ARKANSAS. FOR THIS UPDATE...WILL MAINTAIN WARNINGS AND ADVISORIES AS IS. ONLY CHANGE WAS TO DECREASE POPS ACROSS DEEP EAST TEXAS AND WEST CENTRAL LOUISIANA BASED ON CURRENT RADAR TRENDS. /05/ && .PRELIMINARY POINT TEMPS/POPS... SHV 32 27 38 34 41 / 80 60 30 40 60 MLU 30 27 37 34 39 / 80 60 30 40 60 DEQ 28 24 37 30 41 / 80 50 20 20 50 TXK 30 26 37 31 41 / 80 50 20 20 60 ELD 28 24 38 31 40 / 80 60 20 20 60 TYR 32 27 37 33 41 / 80 60 20 40 60 GGG 33 28 39 33 41 / 80 60 20 40 60 LFK 36 29 41 34 41 / 80 60 30 40 60 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: ARZ070>072. WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: ARZ050-051-059>061-073. LA...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: LAZ001>003. WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: LAZ004>006-010>014-017>022. OK...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: OKZ077. TX...WINTER STORM WARNING UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: TXZ096-097-108>112-124>126-136>138. WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE FOLLOWING ZONES: TXZ149>153-165>167. && $$ 05/05
AREA FORECAST DISCUSSION
NWS CARIBOU ME
344 PM EST MON FEB 23 2015 .SYNOPSIS... COLD HIGH PRESSURE WILL BUILD IN FROM THE WEST TONIGHT THEN SLIDE SOUTH OF THE REGION ON TUESDAY. A TROUGH OF LOW PRESSURE WILL APPROACH TUESDAY NIGHT. LOW PRESSURE WILL DEVELOP SOUTH OF THE AREA EARLY WEDNESDAY AND TRACK INTO THE MARITIMES WEDNESDAY AFTERNOON. && .NEAR TERM /THROUGH TUESDAY/... THE MAIN CHALLENGES THIS TERM WILL BE STREAMERS OFF THE ST. LAWRENCE, WIND CHILLS AND OF COURSE TEMPERATURES. LATEST VISIBLE SATELLITE IMAGERY SHOWED CLOUDS MOVING E OFF THE ST LAWRENCE. LLVL CONVERGENCE SHOWING UP ON THE SURFACE ANALYSIS ACROSS FAR NORTHERN MAINE(THE CROWN MOST PARTICULARLY. PERIODS OF LIGHT SNOW FOR NW AND NE AROOSTOOK COUNTY COULD BRING AN INCH OF SNOW BY THIS EVENING AND THEN WINDS BEGIN TO LET UP. MODEL SOUNDINGS SUPPORT DEEP MOISTURE THROUGH 800MBS W/SOME WEAK FORCING ALOFT. DECIDED TO BOOST POPS UP ACROSS THE FAR NORTHERN AREAS(60-80%) TO ACCOUNT FOR THE SNOW. THE RAP/NAM12 AND HRRR MESOSCALE MODELS WERE DOING WELL W/THIS SETUP. AREAS OF BLOWING SNOW A FACTOR INTO THE EVENING AND WILL CONTINUE THAT WORDING IN THE FORECAST THROUGH 9 PM. HISTORICALLY, CLOUDS AND STREAMERS BREAK UP AS THE WINDS SHIFT MORE TO THE WEST AND THE AIRMASS DRIES OUT. THIS IS SHOWN TO BE THE CASE LATER THIS EVENING. FURTHER S, BASICALLY CLEAR SKIES W/SOME SCT CLOUDS FROM TIME TO TIME. THIS WILL LEAD TO SOME VERY COLD IF NOT BITTERLY COLD TEMPERATURES OVERNIGHT INTO TUESDAY MORNING. WE ARE TALKING 15 TO 25 BELOW ACROSS THE NORTH AND WEST AND PERHAPS 30 BELOW IN THE SHELTERED AREAS. CENTRAL AND DOWNEAST WILL 10 TO 15 BELOW EVEN TO THE COAST. DANGEROUS WIND CHILLS ARE ON THE DOCKET THROUGH EARLY TUESDAY APPROACHING WARNING CRITERIA(-35F) ACROSS THE NORTHERN AND WESTERN AREAS. ATTM, DECIDED TO STAY W/WIND CHILL ADVISORIES AS THE WINDOW LOOKS TO BE SHORT(<3 HRS) FOR WIND CHILLS TO HIT <-35F AND WINDS ARE FORECAST TO DROP OFF BELOW 10 MPH. TUESDAY WILL START OUT SUNNY AND VERY COLD W/HIGH PRES RIDGING INTO THE REGION. THE RIDGE AXIS IF FORECAST TO SLIDE THROUGH THE REGION QUICKLY DURING THE DAY W/CLOUDS ON THE INCREASE BY THE AFTERNOON. DAYTIME TEMPERATURES ACROSS THE NORTHERN 1/2 OF THE CWA IN THE SINGLE NUMBER WHILE CENTRAL AND DOWNEAST WILL SEE 10 TO 15 AT BEST AND THE WARMER TEMPERATURES TOWARD THE COAST. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... A TROUGH OF LOW PRESSURE WILL APPROACH FROM THE GREAT LAKES TUESDAY NIGHT. A SMALL AREA OF LOW PRESSURE WILL DEVELOP ALONG THE SOUTHEASTERN EDGE OF THE TROUGH, OFF THE SOUTHERN NEW ENGLAND COAST, LATE TUESDAY NIGHT. THE FORECAST CHALLENGE WILL BE IN DETERMINING HOW QUICKLY THIS LOW DEVELOPS AND HOW CLOSE THE LOW WILL TRACK TO OUR REGION ON WEDNESDAY. LATEST FORECAST GUIDANCE CARRIES THE LOW INTO THE GULF OF MAINE WEDNESDAY MORNING SPREADING SNOW ACROSS DOWNEAST AREAS VERY EARLY WEDNESDAY MORNING THEN ON UP ACROSS EAST CENTRAL AND NORTHEASTERN AREAS LATER WEDNESDAY MORNING. THIS IS A SMALL, FAST MOVING LOW AND APPEARS WILL NOT BE IN THE AREA LONG ENOUGH TO PRODUCE HEAVY SNOW ACCUMULATIONS. A LIGHT TO MODERATE SNOWFALL OF 3 TO 5 INCHES CURRENTLY APPEARS MOST LIKELY FROM DOWNEAST AREAS NORTHWARD INTO EASTERN AREAS OF NORTHERN MAINE THROUGH WEDNESDAY MIDDAY BEFORE THE LOW LIFTS OUT. THE NAM...GFS AND ECMWF ALL OFFER SIMILAR SOLUTIONS AND HAVE BEEN CONSISTENT WITH PREVIOUS RUNS SHOWING JUST A QUICK SNOWFALL OF MODERATE INTENSITY ACROSS EASTERN AREAS WITH THIS SYSTEM. THE LOW WILL CONTINUE TO INTENSIFY WEDNESDAY AFTERNOON BUT WILL BE QUICK TO LIFT NORTHEAST AND AWAY THROUGH THE MARITIMES AS DRY AND BREEZY WEATHER FOLLOWS. SNOW SHOULD TAPER OFF LATE WEDNESDAY MORNING DOWNEAST AND WEDNESDAY AFTERNOON ACROSS THE NORTHEAST. HIGH PRESSURE WILL THEN BRING DRY AND COLD CONDITIONS WEDNESDAY NIGHT INTO THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A LARGE AREA OF HIGH PRESSURE PUSHING INTO THE EAST WILL MAINTAIN DRY WEATHER THURSDAY NIGHT THROUGH THE COMING WEEKEND. TEMPS AHEAD OF THE HIGH WILL BE WELL BELOW NORMAL INTO SATURDAY, THEN WARM UP CLOSER TO NORMAL LATE IN THE WEEKEND IN THE RETURN FLOW BEHIND THE HIGH ON SUNDAY. CLOUDS WILL INCREASE ON SUNDAY AND SOME SNOW IS POSSIBLE SUNDAY NIGHT INTO MONDAY AS A TROUGH AND WEAK FRONTAL SYSTEM PUSH IN FROM THE WEST. AT THIS TIME THE SYSTEM SUNDAY NIGHT INTO MONDAY LOOKS LIKE A PROGRESSIVE OPEN WAVE WITH ONLY LIGHT TO MODERATE SNOW EXPECTED. DRIER CONDITIONS SHOULD RETURN BEHIND A COLD FRONT LATER MONDAY INTO MONDAY NIGHT. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... NEAR TERM: MVFR W/IFR VSBYS THROUGH EARLY EVENING ACROSS THE NORTHERN TERMINALS(NORTH OF KHUL) DUE TO THE STREAMERS OFF THE ST. LAWRENCE. FURTHER SOUTH, GENERALLY VFR. CLOUDS AND LIGHT SNOW ACROSS THE NORTH WILL END LATER THIS EVENING AS WINDS DROP OFF LEADING TO VFR. IT LOOKS LIKE VFR FOR THE ENTIRE AVIATION SECTOR FOR TUESDAY. SHORT TERM: VFR CONDITIONS TUESDAY NIGHT WILL LOWER TO MVFR THEN IFR VERY LATE AT NIGHT. IFR CONDITIONS IN SNOW ARE EXPECTED WEDNESDAY MORNING. CONDITIONS MAY IMPROVE TO VFR DOWNEAST WEDNESDAY AFTERNOON AND MVFR ACROSS THE NORTH WEDNESDAY AFTERNOON. MAINLY VFR CONDITIONS ARE EXPECTED WEDNESDAY NIGHT AND THURSDAY WITH THE POSSIBLE EXCEPTION OF SOME MVFR CONDITIONS IN THE ST JOHN VALLEY. VFR CONDITIONS ARE THEN EXPECTED THURSDAY NIGHT THROUGH SATURDAY. && .MARINE... NEAR TERM: WINDS ARE NOW HITTING GALE FORCE(35 KTS) ESPECIALLY OVER THE OUTER ZONES AS THE CAA IS HITTING IN EARNEST. WINDS WILL INCREASE FOR A WHILE THIS EVENING W/GUSTS TO 40 KTS. THE NAM12 WAS DOING WELL W/THE CURRENT SETUP. WINDS WILL START DROPPING OFF LATER TONIGHT AS HIGH PRES TO THE SW RIDGES EASTWARD. GALE WARNING WILL REMAIN THROUGH TUESDAY MORNING. EVENING CREW CAN ASSESS THIS FURTHER W/THE LATER GUIDANCE. HEAVY FREEZING SPRAY EXPECTED TONIGHT INTO EARLY TUESDAY THE WARNING IS UP FOR HEAVY ICING POTENTIAL. SEAS ARE COMING UP BUT WERE SLOWER TO RESPOND. SEAS SHOULD TOP OUT AROUND 8 FT OVER THE OUTER ZONES THIS EVENING AND THEN BEGIN TO SUBSIDE LATER TONIGHT AS WINDS DROP OFF. SHORT TERM: AN SCA MAY BE NEEDED LATE TUESDAY NIGHT THROUGH WEDNESDAY AS LOW PRESSURE LIFTS ACROSS THE WATERS. HIGH PRESSURE BUILDING OVER THE AREA SHOULD BRING MAINLY RELATIVELY LIGHT WINDS LATE THIS WEEKEND INTO THE COMING WEEKEND. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WIND CHILL ADVISORY UNTIL 10 AM EST TUESDAY FOR MEZ001>006-010- 011-031-032. WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR MEZ015>017-029-030. MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR ANZ050>052. GALE WARNING UNTIL 4 AM EST TUESDAY FOR ANZ050>052. && $$ NEAR TERM...HEWITT SHORT TERM...BLOOMER LONG TERM...BLOOMER AVIATION...HEWITT/BLOOMER MARINE...HEWITT/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1225 PM EST MON FEB 23 2015 .SYNOPSIS... AN ARCTIC FRONT WILL CROSS THE AREA THIS AFTERNOON. HIGH PRESSURE WILL BUILD ACROSS NORTHERN NEW ENGLAND TONIGHT AND WILL MOVE EAST TUESDAY. DEVELOPING LOW PRESSURE FROM THE WEST WILL CROSS THE AREA WEDNESDAY THEN MOVE TOWARD THE NORTHERN MARITIMES WEDNESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... 1215 PM UPDATE...STREAMER BANDS CONTINUE OFF THE ST. LAWRENCE MOVING ACROSS THE CROWN OF MAINE. THE MOST PROMINENT BAND WAS ACROSS THE ST. JOHN VALLEY UP AROUND THE FRENCHVILLE-MADAWASKA REGION. THE LATEST RUN OF THE RAP MODEL AND HRRR CONTINUE TO DEPICT SOME BANDS HANGING ON INTO THE AFTERNOON ACROSS NORTHERN MAINE AND SLIDING SE IN THE CARIBOU-PRESQUE ISLE REGION. SNOW RATIOS W/THESE BANDS ARE HIGH(20-25:1) YIELDING CLOSE TO AN INCH IN THE HEAVIER BANDS. THE BANDS SHOULD BEGIN TO WEAKEN THIS EVENING AS WINDS START SETTLING DOWN AND THE DIRECTION SHIFTS MORE TO A WNW DIRECTION SHUTTING DOWN THE TRAJECTORY FROM THE ST. LAWRENCE. AREAS OF BLOWING AND DRIFTING SNOW CONTINUE INTO THE EVENING. DECIDED TO KEEP THE WIND CHILL HEADLINES AS THEY ARE FOR NOW. FOR TONIGHT...THE ARCTIC HIGH WILL BUILD INTO NEW ENGLAND OVERNIGHT. TEMPERATURES WILL PLUMMET THROUGH THE EVENING, WITH LOWS -15F TO -25F ACROSS THE NORTHERN HALF OF OUR FORECAST AREA. DOWNEAST AREAS WILL EVEN DROP BELOW ZERO, WITH LOWS OF -5F TO -15F. WINDS WILL GRADUALLY ABATE LATER TONIGHT IN RESPONSE TO THE WEAKENING PRESSURE GRADIENT UNDER THE RIDGE, ESPECIALLY OVER FAR WESTERN LOCATIONS. THEREFORE, IN SPITE OF THE VERY COLD AIR TEMPERATURES, THE WIND CHILL ADVISORY STILL LOOKS APPLICABLE, AS OPPOSED TO A WIND CHILL WARNING. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... THE CORE OF BITTERLY COLD ARCTIC AIR WILL BE MOVG E OF THE FA TUE MORN. AFT A VERY COLD START TO THE DAY...HI TEMPS SHOULD RECOVER INTO THE SINGLE DIGITS BY MID TO LATE AFTN...WITH DOWNEAST AREAS RECOVERING INTO THE TEENS BY ERLY EVE AS SFC WINDS BECOME SRLY COMPONENT BEHIND DEPARTING SFC HI PRES MOVG E TOWARD THE OPEN ATLC. THIS RETURN FLOW WILL BRING INCREASING CLDNSS FROM S TO N ACROSS THE REGION TUE NGT...WITH LGT SN POSSIBLE TO PTNS OF THE FA LATE TUE NGT. MODELS THEN SHOW A S/WV COMPLEX MOVG E FROM CNTRL CAN AND THE GREAT LKS TUE NGT INTO WED. THE SFC LOW WITH THIS SYSTEM IS XPCTD TO REFORM FROM QB TUE NGT TO A SECONDARY LOW OVR THE S GULF OF ME SW OF NOVA SCOTIA. THE SECONDARY LOW THEN GAINS MOMENTUM WED AFTN...ABSORBING THE OLD PRIMARY LOW FROM QB BY WED EVE. A POCKET OF SRLY LOW TO MID LVL WARM/MOISTURE ADVCN BEGINS TO DEVELOP OVR ERN ME BEGINNING ERLY WED MORN JUST AHEAD OF THE DEVELOPING SECONDARY...RESULTING IN MORE ORGANIZED SNFL CLIPPING ERN ME MON MORN INTO ERLY AFTN BEFORE MOVING ENE INTO NB BY LATE WED AFTN. MODELS VARY WITH REGARD TO THE QPF THAT MAY OCCUR OVR ERN ME WITH THE TMG OF THIS EVENT...WITH THE 00Z DTMNSTC CANGEM AND NAM MOST AGGRESSIVE AND THE GFS AND SPCLY ECMWF THE LEAST. WPC IS LEANING MORE WITH THE GFS AND ECMWF MODELS ATTM...SO WE WEIGHT THESE MODELS MORE WITH FCST 6HRLY QPF AND CORRESPONDING SNFL LATE TUE NGT THRU WED. CONSIDERING THE UNCERTAINTY OF TMG OF DEVELOPMENT OF THE SNFL SHIELD BEFORE THE SECONDARY MOVES AWAY FROM THE REGION...WE KEPT SN TO LIQ RATIOS RELATIVELY CONSERVATIVE AT 13.5 TO 1...WHICH RESULTS IN MAX TOTALS OF 3 TO 4 INCHES OVR SE WASHINGTON COUNTY WHERE WE GO WITH CATEGORICAL POPS WITH LESSER AMOUNTS AND POPS TO THE WNW. SN SHOULD TAPER TO SN SHWRS FROM W TO E ACROSS THE REGION FROM MID AFTN TO ERLY EVE...THEN END FROM S TO N OVRNGT WED...WITH STRONGER LLVL COLD ADVCN XPCTD LATE WED NGT AND ERLY THU MORN WITH A SECONDARY ARCTIC COLD FRONT. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... ANOTHER DEEP ARCTIC AIR MASS WILL FOLLOW THE SECONDARY COLD FRONT ACROSS THE REGION FROM CNTRL CAN...WITH THIS AIR MASS NOT QUITE AS COLD AS THE PRIOR AIR MASS AFFECTING THE FA ON TUE. UNDER FAIR SKIES...HI TEMPS WILL BE WELL BLO SEASONAL AVGS FOR THE END OF FEB THU AND FRI...WITH SOME RADIATIONAL COOLING POSSIBLE THU NGT AND MSLY FRI NGT AS LARGE SPRAWLING SFC HI PRES RIDGES ENE INTO THE REGION. WITH WEAK PRES GRAD FLOW INDICATED...THE BEST POTENTIAL FOR COLDEST OVRNGT LOWS WILL BE ACROSS BROAD RVR VLYS OF NRN AND CNTRL PTNS OF THE FA...WITH HILL TOP LCTNS LIKELY MAINTAINING A LGT BREEZE KEEP OVRNGT LOWS NOT AS COLD. ANOTHER WV OF LOW PRES TRACKING OFF THE SE U.S COAST WILL KEEP A LITTLE MORE PRES GRAD AND PERHAPS HI CLD OVR THE DOWNEAST COAST BOTH NGTS LMTG THE POTENTIAL OF VERY COLD LOW TEMPS. SAT SHOULD CONT FAIR...BUT NOT AS COLD AS FCST AFTN 925 MB TEMPS RISE FROM THE LOWER TO MID -20S TO -10S DEG C. WITH THE CNTR OF STRONG SFC HI PRES TRACKING WELL S OF THE FA AS IT MOVES OFF THE MID ATLC COAST...WINDS WILL LIKELY NOT HAVE MUCH CHC TO DECOUPLE EVEN OVR VLY AREAS SAT NGT. SUN WILL BEGIN FAIR...THEN HI/MID CLDNSS INCREASE LATER IN THE DAY AS A LARGE SHIELD OF LGT OVRRNG SNFL APCHS FROM THE GREAT LKS AND QB PROV BY SUN EVE. && .AVIATION /17Z MONDAY THROUGH FRIDAY/... NEAR TERM: MVFR CONDITIONS WITH OCCASIONAL IFR IN LIGHT SNOW AT KHUL/KBHB WILL LINGER THROUGH 14Z OR SO TODAY. THEN CONDITIONS WILL GRADUALLY IMPROVE AS A COLD FRONT CROSSES THE AREA AND ALLOWS COLDER AND DRIER AIR TO SPREAD OVER THE REGION. WEST WINDS WILL INCREASE TO 10-15KT WITH GUSTS TO 25KT POSSIBLE. THIS MAY RESULT IN BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO IFR AT TIMES THROUGH THIS EVENING. OTHERWISE, PREVAILING VFR CONDITIONS ARE EXPECTED FROM 15Z SOUTH/21Z NORTH WITH CLEARING SKIES. SHORT TO LONG TERM: VFR XPCTD ALL TAF SITES TUE THRU TUE EVE...WITH MVFR CLGS POSSIBLE LATE TUE NGT AND THEN MVFR OR IFR VSBYS WITH LGT SNFL DURING THE DAY WED. AFTWRDS...MVFR CLGS CONT ACROSS NRN TAF SITES WED NGT INTO THU MORN WHILE DOWNEAST SITES BECOME VFR. ALL SITES THEN BECOME VFR THU AFTN AND CONT SO THRU FRI. && .MARINE... NEAR TERM: A GALE WARNING REMAINS IN PLACE FOR TODAY AND TONIGHT. A COLD FRONT WILL CROSS THE WATERS THIS MORNING, FOLLOWED BY WEST TO NORTHWEST WINDS OF 20 TO 30 KT WITH GUSTS IN EXCESS OF 35 KT. BITTERLY COLD TEMPERATURES AND THE STRONG WINDS WILL COMBINE TO CREATE HEAVY FREEZING SPRAY, ESPECIALLY OVER THE OUTER WATERS, SO THE FREEZING SPRAY WARNING REMAINS IN PLACE FOR LATER TODAY THROUGH TONIGHT. SHORT TO LONG TERM: SCA OR LESS CONDITIONS XPCTD THRU THIS PTN OF THE FCST. HVY FZGSPY SHOULD BECOME MDT BY 12Z TUE...BECOMING LGT BY LATE DAY AND THEN ENDING BY WED MORN AS COLD ADVCN DIMINISHES OVR THE WATERS AND EVENTUALLY REVERSES TO WARM ADVCN. WENT ABV WW3 GUIDANCE FOR FCST WV HTS BY A FACTOR OF 1.15 OR SO...BASED ON BIAS TRENDS OBSVD OVR THE PAST FEW WEEKS. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WIND CHILL ADVISORY UNTIL 10 AM EST TUESDAY FOR MEZ001>006-010- 011-031-032. WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR MEZ015>017-029-030. MARINE...HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST TUESDAY FOR ANZ050>052. GALE WARNING UNTIL 4 AM EST TUESDAY FOR ANZ050>052. && $$ NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
302 PM EST MON FEB 23 2015 LATEST UPDATE... SYNOPSIS/SHORT TERM/LONG TERM/HYDRO .SYNOPSIS... ISSUED AT 239 PM EST MON FEB 23 2015 A FAST MOVING LOW PRESSURE SYSTEM WILL TRACK EASTWARD THROUGH ONTARIO TONIGHT AND TUESDAY. THIS SYSTEM WILL PROVIDE THE GREAT LAKES REGION WITH WINDY CONDITIONS AND SOME SNOW. CONSIDERABLE DRIFTING SNOW WILL BE POSSIBLE ON TUESDAY. ANOTHER ARCTIC AIRMASS WILL TRACK IN BEHIND THIS DEPARTING STORM AND PERSIST INTO THE WEEKEND. && .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 239 PM EST MON FEB 23 2015 THE MAIN ISSUE DEALS WITH THE IMPACT OF THE LOW PRESSURE SYSTEM THAT TRACKS THROUGH ONTARIO TONIGHT AND TUESDAY. OVERALL IT LOOKS LIKE ENOUGH IMPACTS TO WARRANT HEADLINES FOR THE ENTIRE REGION. I DID CHECK IN WITH A COUPLE OF ROAD COMMISSIONS AND THEY INDICATED THAT WINDS OVER 30 MPH WILL LEAD TO CONSIDERABLE DRIFTING OF THE SNOW...ESPECIALLY IN RURAL AREAS. EVEN SOME HIGHWAYS COULD BE IMPACTED. THE RUC MODEL SHOWS GUSTS TOPPING 40 KNOTS FROM NEAR GRAND RAPIDS NORTHEAST THROUGH MOUNT PLEASANT AND BETTER THAN 35 KNOTS ELSEWHERE. THERE IS A SECONDARY MAX ALONG THE LAKESHORE NORTH OF MUSKEGON...WITH BETTER THAN 40 KNOTS POSSIBLE. I AM NOT CERTAIN WILL SEE SUCH HIGH WINDS. HOWEVER ENOUGH RISK THERE TO GO WITH A HEADLINE. THE MAIN WINDOW OF STRONG WINDS RANGES FROM 09Z TO 18Z FOR LUDINGTON...13Z TO 21Z FOR GRAND RAPIDS AND 16Z TO 23Z FOR JACKSON. SNOW ON TUESDAY WILL BE A SECONDARY CONCERN FOR THIS SYSTEM WITH AMOUNTS EXPECTED TO RANGE FROM 2 TO 4 INCHES OF LAKE ENHANCED SNOW UP NORTH FROM LUDINGTON TO HARRISON. FURTHER SOUTH GRAND RAPIDS AND MOUNT PLEASANT ROUGHLY 1 TO 3 INCHES...TO AN INCH OR LESS FOR JACKSON AND LANSING. STILL...WITH GUSTY WINDS AND SNOW...VISIBILITIES COULD BE REDUCED CONSIDERABLY AT TIMES. LOCATIONS SOUTHEAST OF GRAND RAPIDS COULD START THE DAY OFF WITH SOME SUN. WIND CHILL VALUES ON TUESDAY COULD START OFF AROUND -15 DEGREES...WHICH IS HAZARDOUS. TUESDAY NIGHT AFTER A LULL IN THE WIND...WE COULD SEE A RETURN OF SNOW AND POSSIBLE IMPACTS...MAINLY AFTER MIDNIGHT. WILL NEED TO ASSESS THIS POSSIBILITY WITH LATER FORECASTS. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 239 PM EST MON FEB 23 2015 THE FOCUS OF THE LONG TERM IS THE EVOLUTION OF A SOUTHERN STREAM SYSTEM THAT BOTH THE GFS AND ECMWF HAVE LATCHED ONTO FOR A COUPLE OF DAYS NOW. CONDITIONS LOOK PRETTY DRY...BUT COLD FROM THURSDAY THROUGH SATURDAY...AND LIKELY MONDAY TOO. HOWEVER IT`S THE PERIOD FROM SATURDAY NIGHT THROUGH SUNDAY NIGHT THAT PROMISES TO BE INTERESTING. IT/S LOOKING INCREASINGLY LIKELY THAT PCPN WILL DEVELOP OVER THE SW CWA SATURDAY EVENING...LIKELY AS SNOW...AND CONTINUE THROUGH SUNDAY. THE GULF IS WIDE OPEN DUE TO HIGH PRESSURE NEAR THE EAST COAST AND SO THERE WILL BE A STRONG INFLUX OF MOISTURE. DESPITE THE MOISTURE CONTENT OF THIS SYSTEM...IT STILL HAS SOME ISSUES. ECMWF AND GFS BOTH SHOW THIS BEGINNING AS AN INVERTED TROUGH AND THEN PHASING WITH A NORTHERN STREAM CLIPPER AS IT PUSHES A COLD FRONT THROUGH THE CWA. THIS ISN/T THE CLASSIC STRENGTHENING CLOSED LOW THAT MOVES FROM THE SOUTHERN PLAINS NEWD. AT LEAST NOT YET. QPF WITH THE SYSTEM IS PROGD IN THE 2/3 TO 3/4 INCH RANGE...WHICH IF ALL SNOW WOULD CERTAINLY BE PLOWABLE. THE WARMER ECMWF WOULD LIKELY TURN PCPN TO MIXED RAIN AND SNOW ACROSS THE SOUTHERN CWA. FOR CONTINUITY SAKE WE KEPT THE PCPN AS SNOW IN THE GRIDS FOR NOW. ALL OF THE PCPN WILL LIKELY END MONDAY AS THE SYSTEM MOVES EAST AND ANOTHER SHOT OF COLD AIR MOVES SOUTH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1240 PM EST MON FEB 23 2015 LAKE EFFECT SNOW SHOWERS WILL DIMINISH THIS AFTERNOON AT MKG AND MAY INCREASE A BIT AT GRR AS THE BAND PUSHES INLAND. IT`S POSSIBLE THAT WE COULD SEE A MVFR CIG AT GRR THIS AFTERNOON. OTHERWISE...WINDS WILL INCREASE FROM THE SOUTHWEST AFTER MIDNIGHT AS ANOTHER SYSTEM APPROACHES. SNOW WILL DEVELOP TUESDAY MORNING AT MKG BUT MAY TAKE UNTIL THE AFTERNOON TO DEVELOP AT THE OTHER TAF SITES. && .HYDROLOGY... ISSUED AT 239 PM EST MON FEB 23 2015 WITH NO MAJOR WARM UPS OR RAINFALL HEADED OUR WAY IN THE NEAR FUTURE...RUNOFF WILL BE LIMITED. SERIOUS ICE JAMS AND FLOODING CONCERNS ARE UNLIKELY UNTIL A SIGNIFICANT WARM UP AND RAINFALL OCCUR. CONSIDERABLE ICE DOES EXIST IN THE RIVERS SO WE WILL NEED TO MONITOR TRENDS CLOSELY. FOR NOW WITH CONDITIONS STABLE DUE TO THE ARCTIC AIRMASS IN PLACE...THE RISK IS SOMEWHAT LIMITED FOR FLOODING. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...WINTER WEATHER ADVISORY FROM 4 AM TO 7 PM EST TUESDAY FOR MIZ037>040-043>046-050>052-056>059-064>067-071>074. LM...NONE. && $$ SYNOPSIS...MJS SHORT TERM...MJS LONG TERM...04 AVIATION...04 HYDROLOGY...MJS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1217 PM EST MON FEB 23 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 532 AM EST MON FEB 23 2015 WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT RIDGE FROM THE ERN PACIFIC INTO BC AND MID LEVEL LOW NEAR JAMES BAY RESULTING IN NNW FLOW FROM NRN CANADA INTO THE WRN GREAT LAKES. A VIGOROUS UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER NRN CANADA. AT THE SFC...LIGHT WRLY FLOW PREVAILED ACROSS THE REGION AS ARCTIC HIGH PRES SLOWLY BUILDS TO THE SE TO WRN IA. WITH THE EXTENSIVE ICE COVER ACROSS LAKE SUPERIOR...RADAR/SATELLITE INDICATED ONLY MINIMAL/WEAK LES TO NEAR MUNISING AND GRAND MARAIS THAT WAS SLOWLY LIFTING OFFSHORE AS WINDS BACK. EARLY MORNING TEMPS GENERALLY RANGING BETWEEN -10F TO -20F ALONG WITH WINDS AROUND 5 MPH PRODUCED WIND CHILLS IN THE -20 TO -35 RANGE. TODAY...WIND CHILL VALUES WILL ONLY SLOWLY MODERATE THIS MORNING AS TEMPS CLIMBING BACK TOWARD ZERO WILL BE OFFSET BY INCREASING SW WINDS TO AROUND 10 MPH. OTHERWISE...QUIET WEATHER IS EXPECTED WITH GRADUALLY INCREASING MID AND HIGH CLOUDS IN THE WAA PATTERN BETWEEN THE RETREATING HIGH AND THE CLIPPER LOW MOVING SSE FROM CANADA. THE TIGHTENING PRES GRADIENT WILL BRING GUSTY WINDS BY LATE TODAY MAKING IT STILL FEEL VERY COLD EVEN AS TEMPS CLIMB TO HIGHS NEAR 10F. TONIGHT...THE NRN CANADA SHRTWV WILL QUICKLY DIVE TO THE SSE TO THE NORTH SHORE OF LAKE SUPERIOR BY 12Z/TUE. THE WAA AND PATTERN AND 280K ISENTROPIC LIFT AHEAD OF THE TROUGH WILL BRING WIDESREAD LIGHT SNOW TO THE REGION. EXPECT A DELAY TO THE ONSET OF SNOW TIL LATE EVENING AND OVERNIGHT GIVEN THE VERY DRY AIRMASS IN PLACE OVER THE REGION AND THE TIME TO SATURATE THE 925-700 MB LAYER...PER FCST SOUNDINGS. POTENTIAL SNOWFALL AMOUNTS OF A HALF INCH TO AROUND 2 INCHES ARE CONSISTENT WITH 1.0-1.5 G/KG AVAILABLE DURING THE PERIOD OF STRONGER LIFT AND QPF BETWEEN 0.03-0.08 WITH SLR VALUES AROUND 20/1. THE GREATEST AMOUNTS ARE EXPECTED FROM THE KEWEENAW INTO THE ERN CWA WHERE THE FCST LIFT AND A LONGER PERIOD OF SATURATION IS FCST. POTENTIAL FOR LAKE ENHANCEMENT WITH SW FLOW OFF OF SOME REMAINING OPEN WATER IN NRN LAKE MI SHOULD REMAIN MAINLY EAST OF THE CWA...PER HIGHER RES MODELS 230-250 FCST LOW LEVEL FLOW DIRECTION. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 250 AM EST MON FEB 23 2015 TUESDAY THROUGH SUNDAY WILL BE MARKED BY BOOKEND LOW PRESSURE SYSTEMS...WITH HIGH PRESSURE IN BETWEEN. THE FIRST AT 12Z TUESDAY WILL BE SET UP FROM S HUDSON BAY THROUGH CENTRAL ONTARIO...AND CENTRAL LAKE SUPERIOR...DRAGGING A COLD FRONT ACROSS THE W THIRD OF THE CWA. THE FRONTAL BOUNDARY WILL SWIFTLY EXIT E...AND RESIDE FROM JAMES BAY THRUOGH FAR SE LAKE SUPERIOR BY 18Z TUESDAY. 1-2 IN OF NEW SNOW WILL BE POSSIBLE TUESDAY OVER MUCH OF THE CWA...WITH THE HIGHEST VALUES FAR N AND E. WHILE WINDS ALOFT WILL BE DIMINISHING FROM THE 40-50KT WINDS OVERNIGHT...SFC WINDS WILL BE STEADY TO ON THE INCREASE. LOOK FOR WINDS OF 10-20KTS DURING THE DAY TUESDAY...HIGHEST W AND ALONG LAKE SUPERIOR. WILL BE INTERESTING TO SEE WHAT THE INCREASED SW WINDS TODAY- TONIGHT...AND NW WINDS TUESDAY DO TO THE RELATIVLY THIN AND FRACTURED ICE COVERING MUCH OF LAKE SUPERIOR. HOW IT PROGRESSES WILL HAVE A LARGE IMPACT ON THE AREAL COVERAGE AND INTENSITY OF LAKE EFFECT SNOW BANDS TUESDAY AFTERNOON THROUGH THURSDAY ON MAINLY NW TO WNW WINDS. SLOWLY FALLING INVERSION HEIGHTS TUESDAY NIGHT...AND THE DGZ GOING AWAY AS MUCH COLDER AIR SLIDES IN ON THE NW WINDS WILL RESULT IN THE RETURN OF SMALL SNOWFLAKES THAT WILL NOT ACCUMULATE TO MUCH BUT ARE VERY AFFECTIVE AT REDUCING VIS. ANOTHER COLD ARCTIC ARIMASS WILL BE ABLE TO SLIDE INTO THE REGION AS HIGH PRESSURE OVER MUCH OF THE W HALF OF CANADA SLOWLY SINKS ACROSS S CENTRAL CANADA...THE N AND CENTRAL PLAINS...AND THE UPPER GREAT LAKES BY THE END OF THE WORK WEEK. LIGHT LES ON N TO WNW WINDS WILL BE THE RULE. WIND CHILL VALUES WILL AGAIN FALL INTO THE -20 TO -30F RANGE LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING. THAT 10MPH WIND PORTION OF THE WIND CHILL ADVISORY SHOULD BE MET ACROSS MOST OF THE CWA...WITH STRONGER NW WINDS NEARING 15MPH N CENTRAL AND E ALONG LAKE SUPERIOR. THE APPARENT TEMPERATURE PORTION OF WIND CHILL ADVISORY CRITERIA IS -25 TO -34F. LATE WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING MAY AGAIN BRING US DOWN TO 20 TO NEAR 30 BELOW ZERO WIND CHILLS. HOWEVER...THE NW WINDS SHOULD BE MUCH LIGHTER. THURSDAY NIGHT-FRIDAY WILL BE A PERIOD OF MAINLY W TO WSW WINDS. LAKE EFFECT SNOW SHOWERS SHOULD BE EITHER MIMIMAL OR NON- EXISTANT...AND IMPACTING THE KEWEENAW PENINSULA AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE AROUND AND E OF GRAND MARAIS. EXPECT DRY WEATHER SATURDAY...BUT INCREASING SW WINDS AND INVADING CLOUDS FROM THE W. 850MB TEMPS WILL RISE TO AROUND -11 TO -13C SATURDAY AND SUNDAY. SFC TEMPERATURES SHOULD REBOUND TO NEAR 20F...WHICH IS STILL AROUND 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. SUNDAY SHOULD BE A COUPLE DEGREES WARMER...BUT FILLED WITH MORE CLOUDS AND SNOW FOR THE ENTIRE CWA. EARLY INDICATIONS FROM THE GFS POINT TO 2-5IN OF SNOW CWA WIDE LATE SATURDAY AFTERNOON THROUGH SUNDAY EVENING. THE BEST MOISTURE LOOKS TO REMAIN TO OUR S AS UPPER MI IS IN BETWEEN 2 LOWS /ONE OVER HUDSON BAY...AND ANOTHER EJECTING OUT OF THE CENTRAL PLAINS/. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1217 PM EST MON FEB 23 2015 VFR CONDITIONS WILL CONTINUE AT ALL 3 TAF SITES INTO THIS EVENING. THE SW WINDS WILL STRENGTHEN AND TURN GUSTY AS THE PRESSURE GRADIENT TIGHTENS AHEAD OF A COLD FRONT APPROACHING FROM THE NW. SNOW IN ADVANCE OF THIS FRONT WILL ARRIVE FROM NW TO SE LATE THIS EVENING. THE DRY NATURE OF THE ANTECEDENT AIRMASS WILL MAINTAIN VFR CONDITIONS INITIALLY DESPITE THE THICKENING CLOUD COVER. HOWEVER...CONDITIONS WILL DROP TO MVFR AFT 06Z AND LIKELY TO IFR AT CMX AND IWD WHERE THE HEAVIER SNOW IS EXPECTED AND THE VISIBILITY WILL BE LOW DUE TO BLOWING SNOW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 532 AM EST MON FEB 23 2015 SOUTHWEST WINDS WILL QUICKLY INCREASE THIS AFTERNOON BETWEEN LOW PRESSURE DROPPING SOUTHEAST THROUGH NORTHERN ONTARIO AND HIGH PRES MOVING INTO THE OH VALLEY. THIS WILL LEAD TO SOUTHWESTERLY GALES OF 35-40KTS OVER PORTIONS OF LAKE SUPERIOR THIS AFTERNOON AND EVENING. A GALE WARNING REMAINS IN EFFECT FOR MUCH OF WESTERN/CENTRAL LAKE SUPERIOR FOR LATE THIS AFTERNOON AND TONIGHT. THEN AS A COLD FRONT SLIDES SOUTHEAST ACROSS LAKE SUPERIOR LATE TONIGHT INTO TUESDAY MORNING AND SHIFT WINDS TO THE NORTHWEST...THERE MAY BE A FEW GALE FORCE GUSTS TO 35 KNOTS BEHIND THE FRONT ON TUESDAY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL BUILD BACK INTO THE AREA WEDNESDAY AND REMAIN INTO FRIDAY...LEADING TO GENERALLY LIGHT WINDS BELOW 20KTS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST TUESDAY FOR LSZ266. GALE WARNING FROM 4 PM EST /3 PM CST/ THIS AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...KF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
244 PM CST MON FEB 23 2015 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 230 PM CST MON FEB 23 2015 A STRONG PRESSURE GRADIENT TONIGHT WILL KEEP TEMPS FROM FALLING MUCH...AND WILL LIKELY HOLD AND BEGIN TO RISE OVERNIGHT. TEMPERATURES ACROSS SOUTHERN MANITOBA ARE IN THE MID/UPPER 20S AHEAD OF A STRONG WARM FRONT MOVING INTO THE DAKOTAS THIS AFTN. THESE WARMER TEMPS WILL LIKELY ADVECT SE AND SPREAD ACROSS WESTERN MN DURING THE EVENING...AND ACROSS SOUTHERN MN AFT MIDNIGHT. IN ADDITION...STRONG WAA AHEAD OF THIS FRONT WILL LEAD TO SOME -SN DURING THE EVENING...ESPECIALLY ACROSS CENTRAL AND NORTHERN MN. HOWEVER...THE INITIAL DRY AIR MASS IN SOUTHERN MN WILL LIKELY DISSIPATE ANY PRECIPITATION THAT FALLS UNTIL WELL AFT MIDNIGHT AS ANOTHER STRONGER SHRTWV ACROSS CENTRAL MANITOBA RACING SE OVER MN/WI BY MORNING. LATEST WV IMAGERY SHOWS THIS SHRTWV FAIRLY STRONG...SO I WOULD NOT BE SURPRISE TO SEE SOME ACCUMULATING SNOWFALL IN OUR NE CWA BY LATE TUESDAY MORNING. HOW FAR SW THIS AREA OF LIGHT SNOW OCCURS IS DEPENDENT ON THE DEPTH OF THE MOISTURE AND LOCATION OF THE SHRTWV. BY LATE MORNING...A COLD FRONT WOULD HAVE MOVED ACROSS MOST OF MN...CAUSING TEMPS DURING THE AFTN TO SLOWLY FALL. GUSTY WINDS WILL ALSO CONTINUE THRU THE AFTN AS STRONG CAA DEVELOPS. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 230 PM CST MON FEB 23 2015 NO SIGNIFICANT CHANGES TO THE EXTENDED FORECAST. AS ALLUDED TO IN THE PREVIOUS DISCUSSION...COLD WEATHER IS A CERTAINTY...WITH LINGERING LIGHT SNOW REMAINING POSSIBLE...BUT NOT LIKELY ACROSS CENTRAL MN AND WESTERN WI. THERE ARE TWO MAIN CHANCES FOR PRECIPITATION. THE FIRST COMES WEDNESDAY AS A POTENT PV ANOMALY DIVES ALONG THE MISSOURI RIVER VALLEY AND WILL PRODUCE A QUICK BURST OF MODERATE TO HEAVY SNOWFALL. THE BULLSEYE OF QPF MATCHES UP WILL WITH THE H850 THETA_E ADVECTION...BUT THIS FORCING REMAINS SOUTHWEST OF THE CWA. SO...LIGHT SNOW SHOULD REMAIN CONFINED SOUTH AND WEST OF THE UPPER MINNESOTA RIVER VALLEY. THIS SYSTEM WILL BE FOLLOWED BY ANOTHER ARCTIC HIGH WITH COLD TEMPERATURES AND CLEAR SKIES. THIS HIGH WILL SHIFT EASTWARD AS AN UPPER LEVEL TROUGH CARVES OUT ACROSS THE 4-CORNERS REGION...WITH DOWNSTREAM SOUTHWEST FLOW DEVELOPING ACROSS THE CENTRAL CONUS. THE NORTHERN EXTEND OF THIS SOUTHWEST FLOW WILL DETERMINE THE STORM TRACK...AND POTENTIAL FOR SNOW OVER THE WEEKEND. AT THIS TIME...DID NOT STRAY FROM A BLENDED GUIDANCE...WHICH HAS THE HEAVIEST SNOW CLOSER TO THE I-80 CORRIDOR THAN THE I-90 CORRIDOR. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1125 AM CST MON FEB 23 2015 GUSTY SW WINDS WILL BE THE MAIN CONCERN THRU 00Z AS THE PRESSURE GRADIENT STRENGTHENS. OTHERWISE...VFR CONDS WITH -SN POSSIBLE IN KAXN AFT 01Z BASED ON THE LATEST HRRR REFLECTIVITY RUN. ELSEWHERE...THE MAIN CHC OF -SN WILL HOLD OFF UNTIL AFT 06Z...WITH THE BEST TIME FRAME BETWEEN 9-15Z WHERE BOTH VSBY/CIGS DROP INTO THE MVFR RANGE. A PERIOD OF IFR VSBY IN -SN IS POSSIBLE IN EC MN/WC WI IF THE WX SYSTEM MOVING INTO FAR NW MN STRENGTHENS A BIT MORE. WILL CONTINUE TO MONITOR UPSTREAM OBS IN NW MN AND SEE IF AMD ARE NEEDED THIS AFTN. WINDS WILL REMAIN GUSTY THRU THE NIGHT/MORNING HRS...WITH A SHIFT TO THE WEST/NW BY MORNING. KMSP... MAIN CONCERN IS THE CROSSWIND COMPONENT THIS AFTN WITH WINDS POSSIBLY GUSTING OVER 25 KTS AT TIMES /230-210 DEGREES/. 30 KT GUSTS ARE NOT EXPECTED...BUT WILL MONITOR IF CONDS CHG. OTHERWISE...CIGS WILL LOWER TONIGHT TO LOW END VFR WITH A CHC OF -SN AFT 9Z. MVFR VSBY IN -SN IS POSSIBLE BETWEEN 9-15Z. CONFIDENCE REMAINS LOW ON VSBYS LOWER THAN 3SM IN -SN. WINDS WILL REMAIN GUSTY OVERNIGHT...AND BACK TO THE WEST AFT 9Z...AND TO THE NW BY 12-15Z AS THE COLD FRONT MOVES THRU. /OUTLOOK FOR KMSP/ WED...VFR. WINDS NNW 10 KTS. THU...VFR. WINDS NW 5-10 KTS. FRI...VFR. WINDS WSW 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JLT LONG TERM...JRB AVIATION...JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1128 AM CST MON FEB 23 2015 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 412 AM CST MON FEB 23 2015 THE PRIMARY CONCERN IN THE SHORT TERM WILL BE WIND CHILLS EARLY THIS MORNING...AND THEN ATTENTION SHIFTS TO THE CHANCE FOR LIGHT SNOW LATE TONIGHT. CLEAR SKIES AND SURFACE HIGH PRESSURE HAVE CONTRIBUTED TO QUITE A COLD NIGHT ACROSS THE AREA...WITH WIDESPREAD TEMPERATURES RANGING FROM 10 BELOW TO 20 BELOW ACROSS THE FORECAST AREA. THE COMBINATION OF THESE FRIGID TEMPERATURES WITH A 5-7 MPH WIND HAS YIELDED WIND CHILL READINGS FROM 25 BELOW TO 35 BELOW ACROSS THE MAJORITY OF THE FORECAST AREA. THE ONE EXCEPTION IS ALONG THE MN RIVER VALLEY...WHERE LIGHTER WINDS IN CLOSER PROXIMITY TO THE HIGH PRESSURE RIDGE AXIS HAVE MADE FOR SLIGHTLY WARMER WIND CHILLS IN THE 15 TO 20 BELOW RANGE. WINDS ARE FORECAST TO INCREASE A COUPLE KNOTS AROUND DAYBREAK HOWEVER...WHICH WOULD PUSH APPARENT TEMPERATURES TO AROUND THE 25 BELOW MARK WHERE THEY ARE NOT CURRENTLY MEETING ADVISORY CRITERIA. WILL THEREFORE KEEP THE CURRENT ADVISORY THAT ENCOMPASSES THE ENTIRE CWA IN TACT THROUGH 10 AM CST. THE AFOREMENTIONED INCREASE IN WINDS WILL ENSUE THROUGH THE MORNING HOURS...WITH THE SOUTHWESTERLY DIRECTIONAL COMPONENT YIELDING A MODERATION IN TEMPERATURES FOR WEST CENTRAL AND SOUTHWEST MN. HIGHS THERE WILL CLIMB WELL INTO THE 20S...WHILE CENTRAL MN AND WEST CENTRAL WI EXPERIENCE COOLER HIGHS IN THE 10 TO 20 DEGREE RANGE. HIGH CLOUDS INCREASE THIS AFTERNOON AS A SHORTWAVE APPROACHES FROM CANADA. DEEPER SATURATION AND WEAK LIFT ARRIVE BETWEEN 06Z AND 09Z TUESDAY INTO CENTRAL MN/WI. HAVE INCLUDED 20-30 POPS GENERALLY ALONG AND NORTH OF THE INTERSTATE 94 CORRIDOR...WHERE A COUPLE TENTHS TO A HALF INCH NEW SNOW ON THE GROUND APPEARS POSSIBLE BY DAYBREAK TUESDAY. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 412 AM CST MON FEB 23 2015 DURING THE EXTENDED...WE WILL CONTINUE TO ADD ON TO OUR TEMPERATURE DEPARTURE FOR THE MONTH...WHICH SAW ANOTHER 9 TENTHS OF A DEGREE ADDED ON TO THE DEPARTURE FROM NORMAL AFTER YESTERDAYS AVERAGE TEMPERATURE DEPARTURE OF 27 DEGREES BELOW NORMAL. ON THE MONTH...MSP NOW SITS AT 8.1 DEGREES BELOW NORMAL AND WILL LIKELY FINISH CLOSE TO 10 DEGREES BELOW NORMAL AFTER WE GET 3 MORE DAYS WEDNESDAY...THURSDAY...AND FRIDAY WHERE THE AVERAGE TEMPERATURE DEPARTURE SHOULD BE NEAR OR GREATER THAN 20 DEGREES BELOW NORMAL. THE REASON THE COLD LOOKS TO STAY...IS THE LARGE SCALE WEATHER PATTERN DOES NOT LOOK TO CHANGE ALL THAT MUCH...WITH NOTHING MORE THAN A WESTWARD SHIFT IN THE RIDGE/TROUGH/RIDGE PATTERN THAT HAS BEEN IN PLACE PRETTY MUCH ALL OF FEBRUARY. WITHIN THIS PATTERN...WE WILL BE SCRAPPED BY A STRONG CLIPPER GOING INTO THE WRN GREAT LAKES TUESDAY AND ANOTHER DIVING SOUTH ACROSS THE DAKOTAS ON WEDNESDAY. THE BEST SHOT AT SEEING ANY MEANINGFUL SNOW LOOKS TO COME THIS WEEKEND AS SOUTHERN STREAM ENERGY GETS PULLED INTO THE NORTHERN STREAM. A FEW MINOR CHANGES WERE NEEDED TO THE FORECAST TUESDAY AND WEDNESDAY. HIGHS WERE KNOCKED BACK A COUPLE OF DEGREES ON TUESDAY AS WE WILL BE FIRMLY WITHIN STRONG CAA IN THE WAKE OF THE COLD FRONT COMING THROUGH TONIGHT. THIS WILL LEAD TO GRADUALLY FALLING TEMPERATURES DURING THE AFTERNOON ON TUESDAY AS NW WINDS LIKELY GUST TO BETWEEN 30 AND 40 MPH. ALSO REMOVED THE POPS ACROSS SW MN ON TUESDAY AS THEY WILL BE UNDER THE INFLUENCE OF SUBSIDENCE WITHIN THE RIGHT EXIT REGION OF A NORTHWESTERLY JET STREAK. RAISED THE CHANCE POPS A BIT TUESDAY MORNING IN THE EAST WHERE THE SNOW ARRIVING THERE TONIGHT WILL BE EXITING DURING THE MORNING. LIKE MOST OF THE SYSTEMS WE HAVE SEEN IN THIS PATTERN...THIS WILL ONLY RESULT IN AROUND A HALF INCH OF SNOW IN WRN WI. FOR WEDNESDAY...MODELS CONTINUE TO PAINT A SWATH OF 2-4 INCHES OF SNOW GOING FROM WESTERN NODAK TOWARD WESTERN IOWA. THE BRUNT OF THIS WAVE STILL LOOKS TO REMAIN SW OF THE MPX AREA...THOUGH THE ECMWF/SREF/NAM ALL SHOW THE NE EDGE OF THE SNOW BAND COMING ABOUT AS FAR NE AS THE UPPER MN RIVER VALLEY...SO ADDED SOME CHANCE POPS SW OF THE MN RIVER TO ACCOUNT FOR THAT. STILL NOT CONVINCED WE WILL SEE SNOW IN THE MPX CWA WITH THIS SYSTEM AS NORTHERLY LOW LEVELS WINDS WILL RESULT IN DRY AIR UNDERCUTTING THIS PRECIP SHIELD...WHICH IS THE SCENARIO THE 23.00 AND 23.06 GFS SHOWS PLAYING OUT. BESIDE THE LIGHT SNOW IN THE SW...THIS HIGH WILL BRING US ANOTHER STINT IN ARCTIC AIR TUESDAY NIGHT THROUGH THURSDAY NIGHT. HOWEVER...IT WILL NOT BE QUITE AS COLD AS WHAT WE JUST EXPERIENCED SUNDAY...AS H85 TEMPS WILL BE ABOUT 5C WARMER THAN THEY WERE OVER THE WEEKEND. STILL...HIGHS ON THURSDAY WILL BE MOSTLY IN THE SINGLE DIGITS...WITH DOUBLE DIGIT BELOW ZERO LOWS LIKELY THURSDAY AND FRIDAY MORNINGS ACROSS CENTRAL MN INTO WISCONSIN. OF COURSE THIS COLD MEANS WE WILL HAVE TO BE ON THE LOOKOUT FOR MORE WIND CHILL ISSUES AND WEDNESDAY NIGHT INTO THURSDAY MORNING IS STILL LOOKING TO BRING US ANOTHER ROUND OF WIND CHILL ADVISORY WORTHY APPARENT TEMPERATURES ACROSS CENTRAL MN. FOR THE WEEKEND...THE ECMWF AND GFS CONTINUE TO SHOW A PLOWABLE SNOWFALL HITTING THE SE THIRD OR SO OF THE MPX CWA. THE MAIN DIFFERENCE BETWEEN THE ECMWF AND GFS IS ONE OF TIMING...WITH THE ECMWF BEING ABOUT 12 HOURS BEHIND THE GFS. OTHERWISE...THEY BOTH SHOW A DEEP TROUGH/NEARLY CLOSED UPPER LOW DEVELOPING OVER THE 4 CORNERS REGION BY SATURDAY...WITH A PIECE OF THIS ENERGY GETTING PULLED NE INTO THE GREAT LAKES BY EARLY NEXT WEEK BY A POSITIVELY TILTED NORTHERN STREAM TROUGH WORKING ACROSS SRN CANADA. HAVE INCREASED POPS INTO THE 40S FOR THE SE CWA SATURDAY NIGHT AND SUNDAY. ALTHOUGH IT IS LOOKING INCREASINGLY LIKELY THAT WE WILL START MARCH WITH SHOVEL WORTHY SNOW...MODELS TRADITIONALLY STRUGGLE WITH PHASING SYSTEMS SUCH AS THIS MORE THAN 3 OR 4 DAYS OUT...SO I WOULD NOT GET YOUR HOPES UP TOO MUCH FOR SEEING MEASURABLE UNTIL THE FORECAST LOOKS LIKE THIS TUESDAY OR WEDNESDAY AND BEYOND. ON THE SNOW NOTE...THE REST OF FEBRUARY LOOKS TO GO OFF MOSTLY SNOW FREE...BRINGING TO AN END ONE OF THE LEAST SNOWIEST METEOROLOGICAL WINTERS WE HAVE SEEN IN TWO DECADES. FOR DEC/JAN/FEB...THE 15.6" OF SNOW SO FAR AT MSP AND THE 16.6" AT EAU ARE THE LEAST BOTH LOCATIONS HAVE SEEN SINCE THE WINTER OF 1994-95...WHILE THE PALTRY 9" OBSERVED SO FAR THIS METEOROLOGICAL WINTER AT STC IS THE LEAST SINCE 1986-87. OF COURSE WINTER IN MINNESOTA AND WISCONSIN DOES NOT END WITH FEBRUARY...BUT IT WILL TAKE QUITE THE SPRING RALLY FOR US TO GET OUR SEASONAL SNOWFALL TOTALS UP ANYWHERE NEAR OUR NORMAL OF 50 TO 55 INCHES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1125 AM CST MON FEB 23 2015 GUSTY SW WINDS WILL BE THE MAIN CONCERN THRU 00Z AS THE PRESSURE GRADIENT STRENGTHENS. OTHERWISE...VFR CONDS WITH -SN POSSIBLE IN KAXN AFT 01Z BASED ON THE LATEST HRRR REFLECTIVITY RUN. ELSEWHERE...THE MAIN CHC OF -SN WILL HOLD OFF UNTIL AFT 06Z...WITH THE BEST TIME FRAME BETWEEN 9-15Z WHERE BOTH VSBY/CIGS DROP INTO THE MVFR RANGE. A PERIOD OF IFR VSBY IN -SN IS POSSIBLE IN EC MN/WC WI IF THE WX SYSTEM MOVING INTO FAR NW MN STRENGTHENS A BIT MORE. WILL CONTINUE TO MONITOR UPSTREAM OBS IN NW MN AND SEE IF AMD ARE NEEDED THIS AFTN. WINDS WILL REMAIN GUSTY THRU THE NIGHT/MORNING HRS...WITH A SHIFT TO THE WEST/NW BY MORNING. KMSP... MAIN CONCERN IS THE CROSSWIND COMPONENT THIS AFTN WITH WINDS POSSIBLY GUSTING OVER 25 KTS AT TIMES /230-210 DEGREES/. 30 KT GUSTS ARE NOT EXPECTED...BUT WILL MONITOR IF CONDS CHG. OTHERWISE...CIGS WILL LOWER TONIGHT TO LOW END VFR WITH A CHC OF -SN AFT 9Z. MVFR VSBY IN -SN IS POSSIBLE BETWEEN 9-15Z. CONFIDENCE REMAINS LOW ON VSBYS LOWER THAN 3SM IN -SN. WINDS WILL REMAIN GUSTY OVERNIGHT...AND BACK TO THE WEST AFT 9Z...AND TO THE NW BY 12-15Z AS THE COLD FRONT MOVES THRU. /OUTLOOK FOR KMSP/ WED...VFR. WINDS NNW 10 KTS. THU...VFR. WINDS NW 5-10 KTS. FRI...VFR. WINDS WSW 5 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...LS LONG TERM...MPG AVIATION...JLT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
257 PM EST MON FEB 23 2015 .SYNOPSIS..A COLD FRONT WILL SETTLE SOUTHEAST OF THE AREA THIS AFTERNOON. A WEAK WAVE OF LOW PRESSURE WILL TRACK NORTHEASTWARD ALONG THE FRONT TONIGHT THROUGH TUESDAY... AS ARCTIC HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTH. A SECOND STRONGER LOW PRESSURE AREA WILL TRACK ALONG THE FRONT MIDWEEK... MOVING JUST SOUTHEAST OF THE AREA WEDNESDAY NIGHT THROUGH THURSDAY. && .NEAR TERM /THROUGH TUESDAY NIGHT/... AS OF 1015 AM MONDAY... A LOW AMPLITUDE SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ARE DEPARTING THE SC COAST THIS MORNING. ANAFRONTAL PRECIP MAINLY SOUTHEAST OF THE TRIANGLE AREA WILL ALSO CONTINUE TO EXIT TO THE EAST THROUGH EARLY AFTERNOON. WEAK COLD ADVECTION WILL PERSIST THIS AFTERNOON BEFORE THE STRONGER SURGE OCCURS THIS EVENING AHEAD THE ARCTIC HIGH BUILDING ACROSS THE CENTRAL APPALACHIANS. DUE TO THE DELAYED ARRIVAL OF COLDER LOW-LEVEL AIR...THE WETBULB FREEZING LINE IS STILL WELL TO OUR NORTH IN CENTRAL VA AND BY THE TIME IT SINKS SOUTH IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON... ALL DEEPER MOISTURE AND PRECIP WILL EITHER HAVE DEPARTED OR PRECIP WON`T BE OF SUFFICIENT INTENSITY TO CAUSE WETBULBING OR ANY WINTRY IMPACTS. LATEST GUIDANCE REFLECTS THIS. WILL KEEP THE GENERAL TREND OF POPS GOING AND JUST MAKE SOME ALTERATIONS TO ACCOUNT FOR LATEST RADAR....WITH POPS ENDING AFTER 18Z. WILL ALSO HAVE AN EYE ON THE POTENTIAL FOR A MESOSCALE BAND OF SHALLOW MOISTURE AND PRECIP (MOST LIKELY SLEET BASED ON TEMPS AROUND -10C IN THE SHALLOW SATURATED LAYER) IN THE 21Z TO 03Z TIME FRAME...THOUGH NO IMPACT WOULD BE EXPECTED AT THIS TIME. HI-RES MODELS ARE STILL SPLIT ON WHETHER OR NOT THIS WILL DEVELOP...BUT MODELS HAVE BEEN SHOWING SOMETHING OF THIS NATURE FOR MULTIPLE RUNS. REGARDING TEMPS...THICKNESSES WILL STEADILY FALL THROUGHOUT THE DAY IN THE NORTHEAST FLOW...SO FOR MANY LOCATIONS HIGHS IN THE UPPER 30S NORTH TO MID 40S SOUTH HAVE ALREADY OCCURRED. THE HRRR SHOWS SOME INTERMITTENT BREAKS IN CLOUDS OVER THE THE NORTHWEST PIEDMONT WITH WESTERLY FLOW ALOFT AND NOT AS MUCH LOW-LEVEL MOISTURE THERE. NOT CONFIDENT IN THE UPPER 40S THE HRRR GIVES...BUT THERE COULD BE A LITTLE WARMING THROUGH EARLY AFTERNOON. TONIGHT: THE SECOND BATCH OF S/W ENERGY MOVES INTO THE AREA BETWEEN 06 TO 12Z TUESDAY. RESULTANT WEAK DPVA AND SHALLOW ISENTROPIC UPGLIDE WILL RE-NEW/DEEPEN SATURATION ALOFT TO SUPPORT SOME LIGHT SNOW AND FLURRIES INTO THE AREA AROUND DAYBREAK ACROSS THE WESTERN AND SOUTHERN PORTIONS OF THE FORECAST AREA. MODELS ARE ONLY GENERATING A HUNDREDTH OR TWO ACROSS THE AREA SO NO ACCUMULATION ARE EXPECTED. CAA WILL GOVERN LOWS TONIGHT...RANGING FROM UPPER TEENS ACROSS THE NE TO MID 20S SOUTH. TUESDAY AND TUESDAY NIGHT: TRANSITORY ARCTIC HIGH PRESSURE WILL HAVE SETTLED ACROSS THE HEART OF CENTRAL NC BY TUESDAY MORNING. THIS HIGH PRESSURE WILL BE NUDGED OFFSHORE BY LATE DAY AS A FAST MOVING SHORT WAVE MOVES EAST ACROSS THE AREA. BRIEF SOUTHERLY FLOW AND WEAK SUPPORT ALOFT WILL POTENTIALLY PRODUCE SOME LIGHT SNOW/FLURRIES...MAINLY ACROSS THE SOUTHERN TIER AND THE WESTERN PIEDMONT TUESDAY MORNING THROUGH AROUND MID DAY. OTHERWISE...SKIES WILL REMAIN BE MOSTLY CLOUDY THROUGH THE DAY WITH HIGHS PEAKING IN THE MID TO UPPER 30S. MINOR MODERATION IN MIN TEMPS IS EXPECTED TUE NIGHT WITH DOWNSLOPE WARMING IN GENERALLY WESTERLY LOW LEVEL FLOW AIDED BY STREAMING MID TO HIGH CLOUDINESS ALOFT IN THE FAST CONFLUENT FLOW. MINS WILL BE MOSTLY IN THE MID 20S. -MLM && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 355 PM MONDAY... THERE IS STILL A BIT OF UNCERTAINTY WITH THE TRACK OF A LOW THAT DEVELOPS OVER THE GULF AND MOVES NORTHEAST ALONG THE SOUTHEAST U.S. COAST AND THUS THE CONFIDENCE IS BELOW AVERAGE. HOWEVER...GIVEN THAT THE TRACK OF THE LOW IS NOT LIKELY TO SHIFT SIGNIFICANTLY...IT IS LIKELY THAT SNOW WILL OCCUR OVER A PORTION OF CENTRAL NC WEDNESDAY NIGHT THROUGH THURSDAY MORNING...WITH HIGH CHANCES OF RAIN OR SNOW ACROSS THE ENTIRE AREA. KEEP IN MIND THOUGH THAT CHANGES IN THE LOW TRACK WILL RESULT IN CHANGES TO THE P-TYPE...DURATION...AND AMOUNTS. THE LATEST GFS ANALYZES THE LOW FARTHER EAST THAN THE ECMWF... FAVORING LOWER RAIN/SNOW AMOUNTS BUT BETTER CHANCES FOR SNOW THAN RAIN. SHOULD THE LOW TRACK BE FARTHER EAST IT WOULD FAVOR EVEN LESS PRECIP. HOWEVER...A TRACK CLOSER TO THE CAROLINA COAST WOULD FAVOR MORE PRECIP BUT HIGHER CHANCES OF RAIN THAN SNOW. REGARDLESS... CURRENT FORECASTS SUGGEST A NOT SO NICE 12-24 HOUR PERIOD AND AS OF THE LATEST FORECAST EXPECT SNOW ACCUMULATIONS OF UP TO 2 INCHES IN THE NORTHEAST. TEMPERATURES WEDNESDAY AFTERNOON IN THE MID TO UPPER 40S WILL DECREASE INTO THE MID 20S NORTH TO AROUND 30 DEGREES SOUTH WITH AT LEAST SOME SNOW POSSIBLE OVER THE ENTIRE CWA. TEMPERATURES WILL RISE INTO THE UPPER 30S TO LOW 40S ON THURSDAY...WITH ALL LINGERING PRECIPITATION CHANGING OVER TO RAIN BEFORE ENDING THURSDAY EVENING/NIGHT. THE LOW WILL START TO MOVE AWAY FROM THE COAST... ALLOWING HIGH PRESSURE TO BUILD IN. DESPITE THE LINGERING CLOUDS... THE COLD ADVECTION SHOULD BE ENOUGH TO RESULT IN LOW TEMPS IN THE LOW TO MID 20S ACROSS THE AREA THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 255 PM MONDAY... HIGH PRESSURE WILL BUILD EAST TOWARD NC ON FRIDAY...HOWEVER COLD AIR ADVECTING INTO THE REGION WILL RESULT IN HIGHS ONLY IN THE MID 30S NORTH TO AROUND 40 DEGREES SOUTHWEST. OVERNIGHT LOWS IN THE UPPER TEENS TO LOW 20S EXPECTED FRIDAY NIGHT. BOTH THE GFS AND THE ECMWF PREDICT HIGH PRESSURE TO TRAVERSE THE GREAT LAKES REGION DURING THIS TIME PERIOD...RIDGING SOUTH INTO CENTRAL NC ON SATURDAY NIGHT AND LINGERING THROUGH THE WEEKEND. THE BIG QUESTION WILL BE HOW LONG THE WEDGE AIRMASS LINGERS OVER THE NORTHWEST...AND HOW THAT WILL IMPACT BOTH TEMPERATURES AND WEATHER TOWARD THE END OF THE WEEKEND AND INTO MONDAY. WITH SIGNIFICANT MODEL DIFFERENCES DURING THIS PART OF THE FORECAST...CONFIDENCE REMAINS LOW. GENERALLY...EXPECT INCREASING PRECIPITATION CHANCES FROM WEST TO EAST THROUGH MONDAY WITH GRADUALLY MODERATING TEMPERATURES FROM UPPER 30S NW TO LOW 40S SE ON SATURDAY TO MID 50S NW TO POSSIBLY LOW 60S SOUTH ON MONDAY. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 100 PM MONDAY... PRIMARY AVIATION CONCERN NEXT 24 HRS: MVFR CIGS AT RDU/RWI/FAY THROUGH EARLY THIS EVENING... THEN RETURNING TO INT/GSO TOWARD MIDNIGHT... AND RETURNING TO RDU/RWI/FAY TUE MORNING. A COLD FRONT HAS SETTLED SOUTHEAST OF CENTRAL NC EARLY THIS AFTERNOON... AFTER BRINGING PATCHY RAIN AND SUB-VFR CIGS TO AREA TERMINALS. CIGS AT INT/GSO HAVE RISEN TO VFR AS CHILLY HIGH PRESSURE BEGINS TO BUILD IN FROM THE NORTH AND NW... HOWEVER MVFR CIGS PERSIST AT RDU/FAY/RWI. AT INT/GSO... VFR CONDITIONS WILL HOLD UNTIL AROUND 05Z OR 06Z... WHEN MVFR OR IFR CIGS WILL RETURN AND LIKELY LINGER THROUGH THE END OF THE TAF VALID PERIOD. AT RDU/FAY/RWI... MVFR CIGS SHOULD PERSIST UNTIL THE 02Z-05Z TIME FRAME... WHEN CIGS SHOULD IMPROVE TO VFR. OCCASIONAL GUSTS ARE ALSO EXPECTED AT THESE THREE SITES THIS AFTERNOON. VFR CONDITIONS SHOULD HOLD OVERNIGHT AT THESE 3 SITES THROUGH DAYBREAK TUE AS THE HIGH PRESSURE CONTINUES TO BUILD IN... BUT THEN AFTER 13Z TUE... AN APPROACHING DISTURBANCE ALOFT TRACKING ACROSS THE GULF AND SOUTHEAST STATES WILL BRING A RETURN TO MVFR OR IFR CONDITIONS STARTING MID MORNING TUE. A LITTLE LIGHT SNOW IS POSSIBLE STARTING TUE MORNING... ESPECIALLY AT FAY... HOWEVER AMOUNTS SHOULD BE VERY LIGHT... AND WHILE VSBYS MAY DROP TO MVFR... THERE IS TOO MUCH UNCERTAINTY AT THIS RANGE TO INCLUDE THIS IN THE TAFS AT THIS TIME... BUT STAY TUNED. LOOKING BEYOND 18Z TUE... CONFIDENCE IS NOT HIGH IN THE DETAILS OF THE FORECAST THROUGH MID WEEK... ALTHOUGH THE WEATHER IS LIKELY TO REMAIN UNSETTLED. THE FRONTAL ZONE HOLDS JUST TO OUR SOUTHEAST... WITH WAVES OF LOW PRESSURE OF VARYING STRENGTH TRACKING ALONG THE FRONTAL ZONE. VFR CONDITIONS SHOULD BE NOTED AT ALL SITES BRIEFLY TUE EVENING/NIGHT... BUT IFR FOG IS POSSIBLE WITH A MOIST AIR MASS IN PLACE. THE STRONGEST LOW PRESSURE WAVE OF THIS SERIES WILL PASS JUST TO OUR SOUTHEAST LATE WED THROUGH THU MORNING... AND THIS WILL BRING THE NEXT GREATEST CHANCE FOR SUB-VFR CONDITIONS AND PRECIPITATION (LIKELY A WINTRY MIX) MAINLY WED EVENING INTO EARLY THU MORNING. SUB-IFR CONDITIONS MAY HOLD AT INT/GSO WITH LOW CLOUDS AND FOG THU INTO FRI... WHILE VFR CONDITIONS ARE NOTED AT OTHER SITES. CHILLY HIGH PRESSURE BUILDING IN FOR THE WEEKEND MAY FINALLY ENSURE A PERIOD OF VFR CONDITIONS AT ALL SITES SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLS/GIH NEAR TERM...CBL/BLS/MLM SHORT TERM...KC LONG TERM...KC AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
100 PM EST MON FEB 23 2015 .SYNOPSIS..A COLD FRONT WILL SETTLE SOUTHEAST OF THE AREA THIS AFTERNOON. A WEAK WAVE OF LOW PRESSURE WILL TRACK NORTHEASTWARD ALONG THE FRONT TONIGHT THROUGH TUESDAY... AS ARCTIC HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTH. A SECOND STRONGER LOW PRESSURE AREA WILL TRACK ALONG THE FRONT MIDWEEK... MOVING JUST SOUTHEAST OF THE AREA WEDNESDAY NIGHT THROUGH THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1015 AM MONDAY... A LOW AMPLITUDE SHORTWAVE AND ASSOCIATED WEAK SURFACE LOW ARE DEPARTING THE SC COAST THIS MORNING. ANAFRONTAL PRECIP MAINLY SOUTHEAST OF THE TRIANGLE AREA WILL ALSO CONTINUE TO EXIT TO THE EAST THROUGH EARLY AFTERNOON. WEAK COLD ADVECTION WILL PERSIST THIS AFTERNOON BEFORE THE STRONGER SURGE OCCURS THIS EVENING AHEAD THE ARCTIC HIGH BUILDING ACROSS THE CENTRAL APPALACHIANS. DUE TO THE DELAYED ARRIVAL OF COLDER LOW-LEVEL AIR...THE WETBULB FREEZING LINE IS STILL WELL TO OUR NORTH IN CENTRAL VA AND BY THE TIME IT SINKS SOUTH IN THE NORTHERN COASTAL PLAIN THIS AFTERNOON... ALL DEEPER MOISTURE AND PRECIP WILL EITHER HAVE DEPARTED OR PRECIP WON`T BE OF SUFFICIENT INTENSITY TO CAUSE WETBULBING OR ANY WINTRY IMPACTS. LATEST GUIDANCE REFLECTS THIS. WILL KEEP THE GENERAL TREND OF POPS GOING AND JUST MAKE SOME ALTERATIONS TO ACCOUNT FOR LATEST RADAR....WITH POPS ENDING AFTER 18Z. WILL ALSO HAVE AN EYE ON THE POTENTIAL FOR A MESOSCALE BAND OF SHALLOW MOISTURE AND PRECIP (MOST LIKELY SLEET BASED ON TEMPS AROUND -10C IN THE SHALLOW SATURATED LAYER) IN THE 21Z TO 03Z TIME FRAME...THOUGH NO IMPACT WOULD BE EXPECTED AT THIS TIME. HI-RES MODELS ARE STILL SPLIT ON WHETHER OR NOT THIS WILL DEVELOP...BUT MODELS HAVE BEEN SHOWING SOMETHING OF THIS NATURE FOR MULTIPLE RUNS. REGARDING TEMPS...THICKNESSES WILL STEADILY FALL THROUGHOUT THE DAY IN THE NORTHEAST FLOW...SO FOR MANY LOCATIONS HIGHS IN THE UPPER 30S NORTH TO MID 40S SOUTH HAVE ALREADY OCCURRED. THE HRRR SHOWS SOME INTERMITTENT BREAKS IN CLOUDS OVER THE THE NORTHWEST PIEDMONT WITH WESTERLY FLOW ALOFT AND NOT AS MUCH LOW-LEVEL MOISTURE THERE. NOT CONFIDENT IN THE UPPER 40S THE HRRR GIVES...BUT THERE COULD BE A LITTLE WARMING THROUGH EARLY AFTERNOON. TONIGHT: THE SECOND BATCH OF S/W ENERGY MOVES INTO THE AREA BETWEEN 06 TO 12Z TUESDAY. RESULTANT WEAK DPVA AND SHALLOW ISENTROPIC UPGLIDE WILL RE-NEW/DEEPEN SATURATION ALOFT TO SUPPORT SOME LIGHT SNOW AND FLURRIES INTO THE AREA AROUND DAYBREAK ACROSS THE WESTERN AND SOUTHERN PORTIONS OF THE FORECAST AREA. MODELS ARE ONLY GENERATING A HUNDREDTH OR TWO ACROSS THE AREA SO NO ACCUMULATION ARE EXPECTED. CAA WILL GOVERN LOWS TONIGHT...RANGING FROM UPPER TEENS ACROSS THE NE TO MID 20S SOUTH. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 330 AM MONDAY... TRANSITORY ARCTIC HIGH PRESSURE WILL HAVE SETTLED ACROSS THE HEART OF CENTRAL NC BY TUESDAY MORNING. THIS HIGH PRESSURE WILL BE NUDGED OFFSHORE BY LATE DAY AS A FAST MOVING SHORT WAVE MOVES EAST ACROSS THE AREA. BRIEF SOUTHERLY FLOW AND WEAK SUPPORT ALOFT WILL POTENTIALLY PRODUCE SOME LIGHT SNOW/FLURRIES...MAINLY ACROSS THE SOUTHERN TIER AND THE WESTERN PIEDMONT TUESDAY MORNING THROUGH AROUND MID DAY. OTHERWISE...SKIES WILL REMAIN BE MOSTLY CLOUDY THROUGH THE DAY WITH HIGHS PEAKING IN THE MID TO UPPER 30S. MINOR MODERATION IN MIN TEMPS IS EXPECTED TUE NIGHT WITH DOWNSLOPE WARMING IN GENERALLY WESTERLY LOW LEVEL FLOW AIDED BY STREAMING MID TO HIGH CLOUDINESS ALOFT IN THE FAST CONFLUENT FLOW. MINS WILL BE MOSTLY IN THE MID 20S. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 330 AM MONDAY... A SOUTHERN STREAM SHORT WAVE MOVING ACROSS THE SOUTHEASTERN GULF STATES HAS BEEN ADVERTISED FOR THE MIDWEEK FOR THE PAST FEW DAYS. THIS SHORT WAVE WILL INDUCE CYCLOGENESIS ALONG THE SOUTHERN STREAM MOISTURE PLUME/STALLED FRONTAL ZONE. THE RESULTING LOW WILL MOVE NORTHEAST ACROSS NORTHERN FLORIDA AND GRAZE THE AREA AS IT MOVES OFF INTO THE MID ATLANTIC. RAIN WILL SPREAD INTO THE SOUTHERN TIER AS EARLY AS WEDNESDAY AFTERNOON...WITH BETTER CHANCES DURING THE OVERNIGHT. COLD AIR WILL BE SURGING SOUTH BEHIND THE LOW...AND EXPECT A SOUTHERLY TRANSITION TO SNOW OVERNIGHT AS MINS FALL INTO THE MID AND UPPER 20S. A CHANCE OF SNOW WILL LINGER INTO THURSDAY MORNING EAST OF INTERSTATE 95...OTHERWISE SKIES WILL REMAIN CLOUDY WITH HIGHS SUFFERING ANOTHER SETBACK AS REINFORCING HIGH PRESSURE AGAIN SETTLES DOWN THE COAST. THURSDAYS HIGHS WILL BE IN THE UPPER 30S NORTH TO LOWER 40S SOUTH. HAVE LITTLE CONFIDENCE IN NAILING DOWN THE FEATURES OF POTENTIAL PRECIP PRODUCING SYSTEMS AS THE WEEKEND APPROACHES IN THIS STUBBORN SPLIT FLOW REGIME...I.E. EVOLUTION AND TIMING OF NORTHERN VS SOUTHERN STREAM FEATURES AND THEIR REFUSAL TO COME INTO PHASE. CONFIDENCE IS HIGH THAT HIGHS FRIDAY THROUGH SUNDAY WILL REMAIN WELL BELOW NORMAL...GENERALLY IN THE UPPER 30S TO LOWER 40S FRIDAY AND SATURDAY...AND LOW AMPLITUDE RIDGING LATE THIS WEEKEND WILL PRODUCE A WARMUP SUNDAY...WITH PERHAPS NEAR NORMAL HIGHS ON MONDAY. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 100 PM MONDAY... PRIMARY AVIATION CONCERN NEXT 24 HRS: MVFR CIGS AT RDU/RWI/FAY THROUGH EARLY THIS EVENING... THEN RETURNING TO INT/GSO TOWARD MIDNIGHT... AND RETURNING TO RDU/RWI/FAY TUE MORNING. A COLD FRONT HAS SETTLED SOUTHEAST OF CENTRAL NC EARLY THIS AFTERNOON... AFTER BRINGING PATCHY RAIN AND SUB-VFR CIGS TO AREA TERMINALS. CIGS AT INT/GSO HAVE RISEN TO VFR AS CHILLY HIGH PRESSURE BEGINS TO BUILD IN FROM THE NORTH AND NW... HOWEVER MVFR CIGS PERSIST AT RDU/FAY/RWI. AT INT/GSO... VFR CONDITIONS WILL HOLD UNTIL AROUND 05Z OR 06Z... WHEN MVFR OR IFR CIGS WILL RETURN AND LIKELY LINGER THROUGH THE END OF THE TAF VALID PERIOD. AT RDU/FAY/RWI... MVFR CIGS SHOULD PERSIST UNTIL THE 02Z-05Z TIME FRAME... WHEN CIGS SHOULD IMPROVE TO VFR. OCCASIONAL GUSTS ARE ALSO EXPECTED AT THESE THREE SITES THIS AFTERNOON. VFR CONDITIONS SHOULD HOLD OVERNIGHT AT THESE 3 SITES THROUGH DAYBREAK TUE AS THE HIGH PRESSURE CONTINUES TO BUILD IN... BUT THEN AFTER 13Z TUE... AN APPROACHING DISTURBANCE ALOFT TRACKING ACROSS THE GULF AND SOUTHEAST STATES WILL BRING A RETURN TO MVFR OR IFR CONDITIONS STARTING MID MORNING TUE. A LITTLE LIGHT SNOW IS POSSIBLE STARTING TUE MORNING... ESPECIALLY AT FAY... HOWEVER AMOUNTS SHOULD BE VERY LIGHT... AND WHILE VSBYS MAY DROP TO MVFR... THERE IS TOO MUCH UNCERTAINTY AT THIS RANGE TO INCLUDE THIS IN THE TAFS AT THIS TIME... BUT STAY TUNED. LOOKING BEYOND 18Z TUE... CONFIDENCE IS NOT HIGH IN THE DETAILS OF THE FORECAST THROUGH MID WEEK... ALTHOUGH THE WEATHER IS LIKELY TO REMAIN UNSETTLED. THE FRONTAL ZONE HOLDS JUST TO OUR SOUTHEAST... WITH WAVES OF LOW PRESSURE OF VARYING STRENGTH TRACKING ALONG THE FRONTAL ZONE. VFR CONDITIONS SHOULD BE NOTED AT ALL SITES BRIEFLY TUE EVENING/NIGHT... BUT IFR FOG IS POSSIBLE WITH A MOIST AIR MASS IN PLACE. THE STRONGEST LOW PRESSURE WAVE OF THIS SERIES WILL PASS JUST TO OUR SOUTHEAST LATE WED THROUGH THU MORNING... AND THIS WILL BRING THE NEXT GREATEST CHANCE FOR SUB-VFR CONDITIONS AND PRECIPITATION (LIKELY A WINTRY MIX) MAINLY WED EVENING INTO EARLY THU MORNING. SUB-IFR CONDITIONS MAY HOLD AT INT/GSO WITH LOW CLOUDS AND FOG THU INTO FRI... WHILE VFR CONDITIONS ARE NOTED AT OTHER SITES. CHILLY HIGH PRESSURE BUILDING IN FOR THE WEEKEND MAY FINALLY ENSURE A PERIOD OF VFR CONDITIONS AT ALL SITES SATURDAY. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLS/GIH NEAR TERM...CBL/BLS SHORT TERM...MLM LONG TERM...MLM AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS TULSA OK
1112 AM CST MON FEB 23 2015 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. FOR THE 18Z TAFS... INTERMITTENT SNOW SHOWERS WILL CONTINUE TO AFFECT ALL SITES THIS AFTERNOON... CREATING TEMPORARY MVFR CONDITIONS. A BRIEF PERIOD OF IFR CONDITIONS MAY BE A POSSIBILITY WITH ANY AREAS OF HEAVIER PRECIPITATION THAT HAPPEN TO PASS OVER A TERMINAL SITE. PRECIPITATION WILL END FROM WEST TO EAST LATE THIS AFTERNOON. WHILE CONDITIONS SLOWLY IMPROVE ACROSS EASTERN OKLAHOMA... MVFR CEILINGS ARE EXPECTED TO PREVAIL THROUGHOUT THE FORECAST PERIOD AT ARKANSAS SITES. && .PREV DISCUSSION... /ISSUED 1056 AM CST MON FEB 23 2015/ ..UPDATE... DISCUSSION... THE HEAVIEST PRECIPITATION CONTINUES TO WORK ITS WAY EAST ACROSS THE FORECAST AREA AND IS ENTERING WEST CENTRAL ARKANSAS. AREAS ALONG AND SOUTH OF INTERSTATE 40 WILL SEE THE BULK OF ACTIVITY FOR THE REMAINDER OF THE DAY. SCATTERED AREAS OF LIGHT PRECIPITATION CONTINUE TO DEVELOP WEST OF THE FORECAST AREA WHICH WILL CONTINUE TO PRODUCE INTERMITTENT ACTIVITY ACROSS MUCH OF THE REMAINDER OF OUR AREA. AS SUCH... HAVE NOT CHANGED POPS OR FORECAST TEMPERATURES FOR THIS AFTERNOON. PREV DISCUSSION... /ISSUED 539 AM CST MON FEB 23 2015/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. WIDESPREAD LIGHT SNOW WILL TRACK ACROSS NE OK / FAR NW AR WITH MINIMAL FLIGHT IMPACTS EXPECTED. MORE WIDESPREAD AND PROLONGED AVIATION IMPACTS ARE EXPECTED ACROSS SE OK INTO WEST CENTRAL ARKANSAS W/ MVFR TO IFR CONDITIONS LIKELY. PRECIP WILL DIMINISH BY EARLY EVENING WITH A TREND TOWARD VFR / MVFR CEILINGS. PREV DISCUSSION... /ISSUED 406 AM CST MON FEB 23 2015/ DISCUSSION... ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS. COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR PLUNGES SOUTH BY THURSDAY. HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW BEYOND THURSDAY. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053- OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075- OKZ076. AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020- ARZ029. && $$ AVIATION...06
AREA FORECAST DISCUSSION
NWS TULSA OK
1056 AM CST MON FEB 23 2015 ...UPDATE... .DISCUSSION... THE HEAVIEST PRECIPITATION CONTINUES TO WORK ITS WAY EAST ACROSS THE FORECAST AREA AND IS ENTERING WEST CENTRAL ARKANSAS. AREAS ALONG AND SOUTH OF INTERSTATE 40 WILL SEE THE BULK OF ACTIVITY FOR THE REMAINDER OF THE DAY. SCATTERED AREAS OF LIGHT PRECIPITATION CONTINUE TO DEVELOP WEST OF THE FORECAST AREA WHICH WILL CONTINUE TO PRODUCE INTERMITTENT ACTIVITY ACROSS MUCH OF THE REMAINDER OF OUR AREA. AS SUCH... HAVE NOT CHANGED POPS OR FORECAST TEMPERATURES FOR THIS AFTERNOON. && .PREV DISCUSSION... /ISSUED 539 AM CST MON FEB 23 2015/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. WIDESPREAD LIGHT SNOW WILL TRACK ACROSS NE OK / FAR NW AR WITH MINIMAL FLIGHT IMPACTS EXPECTED. MORE WIDESPREAD AND PROLONGED AVIATION IMPACTS ARE EXPECTED ACROSS SE OK INTO WEST CENTRAL ARKANSAS W/ MVFR TO IFR CONDITIONS LIKELY. PRECIP WILL DIMINISH BY EARLY EVENING WITH A TREND TOWARD VFR / MVFR CEILINGS. PREV DISCUSSION... /ISSUED 406 AM CST MON FEB 23 2015/ DISCUSSION... ANOTHER ROUND OF WINTER WEATHER IS ABOUT TO GET UNDERWAY ACROSS PARTS OF EASTERN OK EARLY THIS MORNING. A LARGE AREA OF SHOWERY PRECIP HAS SPREAD ACROSS WESTERN/CENTRAL OK A LITTLE AHEAD OF SCHEDULE...WITH SEVERAL REPORTS OF GRAUPEL OR ICE PELLETS DESPITE ALL MODEL SOUNDINGS POINTING TO SNOW. STILL BELIEVE THIS WILL MAINLY BE A SNOW EVENT FOR ALL BUT FAR SOUTHERN OK BUT THE CONVECTIVE NATURE OF AT LEAST THIS EARLY ROUND OF PRECIP LENDS SOME CONFIDENCE TO ADDING A SLEET/SNOW MIXTURE NORTH TO ABOUT I-40 THIS MORNING. OVERALL CONFIGURATION AND TIMING OF ADVISORY APPEARS GOOD FOR NOW...THOUGH MUCH OF THE EVENT MAY BE DONE WELL BEFORE 00Z EXPIRATION TIME. LATEST RUNS OF HRRR HAVE ALSO SPREAD HEAVIER SNOW TOTALS A BIT FARTHER NORTH ACROSS EASTERN OK AND THIS WILL NEED TO BE WATCHED THROUGHOUT THE DAY. TEMPS TODAY WILL NOT GO MUCH OF ANYWHERE WITH MOSTLY LOW/MID 20S FOR HIGHS. COLD AND DRY TONIGHT WITH A MODEST WARM UP ON TUESDAY...WHICH WILL FEEL NICE AFTER LAST COUPLE OF DAYS DESPITE BEING SEVERAL DEGREES BELOW NORMAL. UPPER LEVEL SYSTEM OVER THE SOUTHWEST WILL MOVE EAST ACROSS TEXAS TUE NIGHT INTO WED...WITH A SMALL CHANCE OF PRECIP SPREADING INTO SE OKLAHOMA DURING THAT TIME IN THE FORM OF LIGHT SNOW OR SLEET. THIS IS NOT EXPECTED TO BE MUCH OF AN ISSUE AS THE HEAVIER PRECIP SHOULD STAY SOUTH OF THE RED RIVER. A NICE WARM UP FOR WEDNESDAY BUT NOT FOR LONG AS ANOTHER SURGE OF MUCH COLDER AIR PLUNGES SOUTH BY THURSDAY. HIGH LEVELS OF UNCERTAINTY IN THE EXTENDED FORECAST BUT IT DOES APPEAR THAT TEMPS WILL WARM UP BY NEXT WEEKEND...ENOUGH FOR ANY PRECIP TO BE LIQUID. THERE STILL MAY BE A TRANSITION PERIOD LATE IN THE WEEK HOWEVER SO WINTER WEATHER POTENTIAL WILL STILL BE PRESENT FOR THU INTO SAT. FORECAST CONFIDENCE REMAINS QUITE LOW BEYOND THURSDAY. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR OKZ049-OKZ053- OKZ065-OKZ066-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075- OKZ076. AR...WINTER WEATHER ADVISORY UNTIL 6 PM MONDAY FOR ARZ019-ARZ020- ARZ029. && $$ SHORT TERM...06
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1152 AM CST MON FEB 23 2015 .AVIATION... FREEZING TEMPERATURES WILL REMAIN ALONG AND NORTH OF A KDRT TO KHDO TO KHYI TO KGYB LINE THIS AFTERNOON INTO THIS EVENING. THE PORTION EAST OF KHDO SAGS SOUTH TO A KSAT TO KENEDY TO K66R LINE BY SUNRISE TUESDAY AND THEN MOVES BACK TO NORTH TUESDAY. PATCHY -DZ PERSISTS THIS AFTERNOON AND SLOWLY SHIFTS INTO EASTERN AREAS TONIGHT INTO TUESDAY WITH -FZDZ NORTH OF THE FREEZE LINE. HAVE CONTINUED -FZDZ FOR KAUS THROUGH MIDDAY TUESDAY AND -DZ FOR KSAT/KSSF THROUGH THIS EVENING. SOME ICING IS POSSIBLE FROM JUST ABOVE THE GROUND UP TO 4K FEET. OTHERWISE...IFR/MVFR CIGS PREVAIL THIS AFTERNOON THROUGH TUESDAY. NLY WINDS 12 TO 17 KTS WITH GUSTS TO 25 KTS PREVAIL THIS AFTERNOON...THEN DECREASE TO LESS THAN 10 KTS TONIGHT...THEN SLOWLY TURN TO NELY ON TUESDAY. EXCEPT...ALONG THE RIO GRANDE WHERE THE TURN TO NELY AND ELY TAKES PLACE TONIGHT. && .PREV DISCUSSION... /ISSUED 530 AM CST MON FEB 23 2015/ AVIATION UPDATE...FOR 12Z TAF PACKAGE... CURRENT CONDITIONS WILL LIKELY PERSIST THROUGH ENTIRE TAF PERIOD. THERE IS SOME CONCERN FOR -FZDZ THIS MORNING FOR KAUS SO INCLUDED TEMPO GROUP TO HANDLE THAT. OTHERWISE -DZ EXPECTED FOR ALL TERMINALS TODAY. AS PREVIOUS FORECAST MENTIONED...ICING WILL BE A CONCERN FOR THE LOWEST 3KFT JUST OFF THE SURFACE DURING TAKEOFF AND LANDING FOR ALL TERMINALS. OTHERWISE...MVFR/IFR CEILINGS ARE EXPECTED THROUGHOUT THE DAY AND NIGHT. GUSTY WINDS WILL ALSO PERSIST THROUGH THE DAY. PREV DISCUSSION... /ISSUED 457 AM CST MON FEB 23 2015/ SHORT TERM (TODAY THROUGH TUESDAY)... EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP. OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM TODAY. OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING. WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE WEST. LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)... ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 33 30 43 36 58 / 70 30 20 30 30 AUSTIN BERGSTROM INTL AIRPORT 34 30 43 34 57 / 70 30 20 30 30 NEW BRAUNFELS MUNI AIRPORT 36 30 45 37 61 / 60 30 10 30 20 BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20 DEL RIO INTL AIRPORT 38 34 52 41 68 / 50 10 10 10 - GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30 HONDO MUNI AIRPORT 37 32 48 38 65 / 50 20 10 20 - SAN MARCOS MUNI AIRPORT 35 30 44 37 59 / 70 30 10 30 20 LA GRANGE - FAYETTE REGIONAL 38 31 43 38 57 / 70 40 20 30 30 SAN ANTONIO INTL AIRPORT 38 31 45 38 62 / 60 30 10 20 10 STINSON MUNI AIRPORT 39 32 46 39 63 / 60 30 10 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL VERDE...WILLIAMSON. && $$ MESOSCALE/AVIATION...04 SYNOPTIC/GRIDS...17 PUBLIC SERVICE/DATA COLLECTION...00
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
1141 AM CST MON FEB 23 2015 .UPDATE... LIGHT FREEZING RAIN/DRIZZLE CONTINUE TO AFFECT THE NORTHEAST PART OF SOUTH CENTRAL TEXAS LATE THIS MORNING. CURRENTLY TEMPERATURES ARE IN THE UPPER 20S AND LOWER 30S ACROSS THOSE LOCATIONS. AREA RADARS AND HIRES MODEL SOLUTIONS ARE ENDING PRECIPITATION BY NOON OR 1 PM THIS AFTERNOON ACROSS MOST AREAS. HOWEVER...THERE IS A SLIGHT CHANCE FOR FREEZING DRIZZLE ACROSS THE NORTHERN PORTION OF THE HILL COUNTRY...ESPECIALLY...NORTH OF A LLANO TO LAKEWAY TO TAYLOR LINE. TEMPERATURES WILL REMAIN IN THE UPPER 20S AND LOWER 30S FOR THE REMAINDER OF THE DAY ACROSS THE HILL COUNTRY AND MID TO UPPER 30S EAST OF THE I35 CORRIDOR. ICE ACCUMULATIONS ARE NOT EXPECTED...HOWEVER...A THIN LAYER OF ICING ON THE GROUND...MAY BE POSSIBLE OVER SOME LOCATIONS AND RESULTING IN MINOR TRAVEL IMPACTS. && .PREV DISCUSSION... /ISSUED 530 AM CST MON FEB 23 2015/ AVIATION UPDATE...FOR 12Z TAF PACKAGE... CURRENT CONDITIONS WILL LIKELY PERSIST THROUGH ENTIRE TAF PERIOD. THERE IS SOME CONCERN FOR -FZDZ THIS MORNING FOR KAUS SO INCLUDED TEMPO GROUP TO HANDLE THAT. OTHERWISE -DZ EXPECTED FOR ALL TERMINALS TODAY. AS PREVIOUS FORECAST MENTIONED...ICING WILL BE A CONCERN FOR THE LOWEST 3KFT JUST OFF THE SURFACE DURING TAKEOFF AND LANDING FOR ALL TERMINALS. OTHERWISE...MVFR/IFR CEILINGS ARE EXPECTED THROUGHOUT THE DAY AND NIGHT. GUSTY WINDS WILL ALSO PERSIST THROUGH THE DAY. PREV DISCUSSION... /ISSUED 457 AM CST MON FEB 23 2015/ SHORT TERM (TODAY THROUGH TUESDAY)... EARLY MORNING OBSERVATIONS SHOW THE FREEZING LINE ROUGHLY ALONG A GEORGETOWN TO BOERNE TO COMSTOCK LINE. OBSERVATIONS ALSO SHOW LIGHT MIXED PRECIPITATION FALLING ACROSS THE HILL COUNTRY WITH ONLY TRACE AMOUNTS REPORTED SO FAR. OTHERWISE...RADAR ECHOES GENERALLY ON THE INCREASE EARLY THIS MORNING...ESPECIALLY ACROSS THE NORTHERN HILL COUNTRY INCLUDING KERR...GILLESPIE...LLANO AND BURNET COUNTIES. THE LATEST HRRR AND NAM12 MODELS TEND TO FAVOR THE ABOVE MENTIONED AREAS FOR PRECIPITATION TODAY AND WE HAVE PLACED THE HIGHEST CHANCE FOR WINTRY PRECIPITATION HERE. WE/LL NEED TO MONITOR THESE AREAS CAREFULLY AS ICE ACCUMULATIONS COULD ADD UP QUICKER IF MULTIPLE ROUNDS OF PRECIPITATION DEVELOP. OTHERWISE...WE STILL EXPECT WINTRY PRECIPITATION IN THE FORM OF FREEZING RAIN TO OCCUR ACROSS THE SOUTHERN EDWARDS PLATEAU...HILL COUNTRY AND PORTIONS OF THE INTERSTATE 35 CORRIDOR MAINLY NORTH OF SAN MARCOS. WE STILL EXPECT ICE ACCUMULATIONS TO REMAIN AT OR BELOW 1/10 OF AN INCH...WITH THE MAIN IMPACTS BEING ON BRIDGES AND ELEVATED ROADWAYS. THE WINTER WEATHER ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM TODAY. OTHERWISE...TEMPERATURES WILL EITHER REMAIN STEADY OF SLOWLY FALL TODAY DUE TO THE COMBINATION OF COLD AIR ADVECTION...CLOUD COVER AND LIGHT PRECIPITATION. FOR THE EVENING AND OVERNIGHT HOURS...WE EXPECT A FAIRLY QUICK DECREASE IN PRECIPITATION CHANCES FROM WEST TO EAST ACROSS THE REGION. WE CONTEMPLATED EXPANDING THE WINTER WEATHER ADVISORY FARTHER EAST TO COVER AREAS MAINLY NORTH OF I-10/EAST OF I-35. HOWEVER...THE MODELS HAVE BEEN CONSISTENT IN SHOWING A RATHER QUICK DECREASE IN THE PRECIPITATION THIS EVENING. WE/LL CONTINUE TO HIGHLIGHT THIS REGION IN A SPECIAL WEATHER STATEMENT TO COVER THE COLD TEMPERATURES AND POTENTIAL FOR LIGHT WINTRY PRECIPITATION. PRECIPITATION CHANCES TEMPORARILY DECREASE ON TUESDAY AS MID-LEVEL DRYING/WEAK SUBSIDENCE MOVE IN FROM THE WEST. LONG TERM (TUESDAY NIGHT THROUGH SUNDAY)... ANOTHER UPPER LEVEL TROUGH APPROACHES SOUTH CENTRAL TEXAS FROM THE WEST TUESDAY NIGHT. THE LATEST ROUND OF MODEL GUIDANCE IS SHOWING THIS SYSTEM TO BE A LITTLE STRONGER WHEN COMPARED TO PREVIOUS RUNS. WE HAVE INCREASED PRECIPITATION CHANCES SLIGHTLY FOR TUESDAY NIGHT AND WEDNESDAY. AT THIS TIME...TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING TUESDAY NIGHT...SO WE/LL KEEP THE PRECIPITATION AS ALL LIQUID. AS THE ABOVE MENTIONED UPPER LEVEL STORM SYSTEM DEPARTS THE REGION BY LATE WEDNESDAY... ANOTHER SYSTEM MOVES THROUGH ON THURSDAY. WE/LL KEEP THE FORECAST DRY AS MOISTURE WILL BE LACKING. WE DO EXPECT ANOTHER SHOT OF COOLER AIR TO MOVE THROUGH ON THURSDAY...FOLLOWED BY COOLER TEMPERATURES ON FRIDAY. WE/LL KEEP A SLIGHT CHANCE FOR LIGHT RAIN IN THE FORECAST FRIDAY THROUGH SUNDAY AS SOUTHERLY FLOW JUST ABOVE THE COLD SURFACE AIR BEGINS TO SET UP A WARM AIR ADVECTION PATTERN. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 33 30 43 36 58 / 70 30 20 30 30 AUSTIN BERGSTROM INTL AIRPORT 34 30 43 34 57 / 70 30 20 30 30 NEW BRAUNFELS MUNI AIRPORT 36 30 45 37 61 / 60 30 10 30 20 BURNET MUNI AIRPORT 31 26 41 34 57 / 80 30 20 30 20 DEL RIO INTL AIRPORT 38 34 52 41 68 / 50 10 10 10 - GEORGETOWN MUNI AIRPORT 33 27 42 34 56 / 70 40 20 30 30 HONDO MUNI AIRPORT 37 32 48 38 65 / 50 20 10 20 - SAN MARCOS MUNI AIRPORT 35 30 44 37 59 / 70 30 10 30 20 LA GRANGE - FAYETTE REGIONAL 38 31 43 38 57 / 70 40 20 30 30 SAN ANTONIO INTL AIRPORT 38 31 45 38 62 / 60 30 10 20 10 STINSON MUNI AIRPORT 39 32 46 39 63 / 60 30 10 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...HAYS...KENDALL...KERR...LLANO...REAL...TRAVIS...VAL VERDE...WILLIAMSON. && $$ MESOSCALE/AVIATION...04 SYNOPTIC/GRIDS...17 PUBLIC SERVICE/DATA COLLECTION...00
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 253 PM CST MON FEB 23 2015 THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ARCTIC HIGH PRESSURE SETTLING OVER THE MID-MISSISSIPPI VALLEY AND EXTENDING ACROSS THE EASTERN GREAT LAKES. CLEAR SKIES REMAIN ACROSS MOST OF THE REGION EARLY THIS AFTERNOON WITH WIND CHILLS WARMING INTO THE 5 TO 15 BELOW RANGE. CLOUDS ARE INCREASING OVER THE NORTHERN PLAINS AHEAD OF A SHORTWAVE DIVING SOUTHEAST OVER LAKE WINNIPEG. LIGHT SNOW AND BLOWING SNOW ARE OCCURRING AHEAD OF THIS SHORTWAVE BUT THESE ARE OCCURRING MAINLY NORTH OF THE BORDER. SOME WIND GUSTS ARE REACHING BETWEEN 30 AND 35 KNOTS. AS THIS SHORTWAVE AND A MORE POTENT WAVE BEHIND IT MOVING INTO THE REGION...SNOWFALL POTENTIAL AND IMPACTS ARE THE MAIN FORECAST CONCERNS. TONIGHT...LEAD SHORTWAVE TROUGH OVER THE LAKE WINNIPEG REGION WILL WEAKEN AS IT MOVES INTO THE REGION THIS EVENING. THE ARCTIC AIRMASS AHEAD OF THIS WAVE IS VERY DRY...WHICH SHOULD KEEP THE AREA PRECIP-FREE THROUGH THE EVENING. THEN AS A SECONDARY AND STRONGER SHORTWAVE ARRIVES LATE TONIGHT...STRONG FORCING SHOULD PUSH AN AREA OF LIGHT SNOW ACROSS THE REGION FROM NORTHWEST TO SOUTHEAST...POSSIBLY MAKING IT INTO THE FOX VALLEY BY 12Z. ALTHOUGH ACCUMULATIONS ARE EXPECTED TO REMAIN UNDER AN INCH...GUSTY SOUTHWEST WINDS AHEAD OF THE SHORTWAVE WILL LEAD TO BLOWING AND DRIFTING SNOW IN THE OPEN COUNTRY. THE CLOUDS AND WIND WILL PREVENT TEMPS FROM FALLING MUCH TONIGHT...AND WILL GO WITH LOWS IN THE MIDDLE SINGLE DIGITS ABOVE ZERO. WIND CHILLS WILL CONTINUE TO RANGE FROM 10 TO 20 BELOW THIS EVENING...THEN WARM AS TEMPERATURES RISE OVERNIGHT. TUESDAY...THE LIGHT SNOW WILL CONTINUE TO SPREAD ACROSS THE FOX VALLEY AND LAKESHORE AREAS EARLY IN THE MORNING BEFORE EXITING LATE IN THE MORNING. MID-LEVEL MOISTURE PEELS OUT BEHIND THE SHORTWAVE DURING THE AFTERNOON...BUT STEEPENING LOW LEVEL LAPSE RATES WITHIN A BROKEN CLOUD DECK COULD YIELD SCATTERED FLURRIES. ADDITIONAL ACCUMULATIONS COULD REACH UP TO A HALF INCH. GUSTY SOUTHWEST WINDS IN THE MORNING WILL TURN TO THE WEST AND THEN NORTHWEST IN THE AFTERNOON AND WILL PROMOTE BLOWING AND DRIFTING SNOW. WIND TRAJECTORIES WILL BE PARALLEL TO DOOR COUNTY INITIALLY...BUT AS WINDS VEER TO THE WEST AND THEN NORTHWEST...BLOWING AND DRIFTING SNOW WILL INCREASINGLY BECOME A HAZARD TO THE WESTERN HALF OF THE COUNTY EVEN AS WINDS SUBSIDE SOMEWHAT WITH THE APPROACH OF A SURFACE TROUGH. SOME DISCUSSION WHETHER DOOR COUNTY WILL NEED A SNOW AND BLOWING SNOW ADVISORY FOR TOMORROW. THINK WINDS WILL BE SOUTHWEST THROUGH MOST OF THE SNOW FALL TOMORROW MORNING AND AM UNCERTAIN HOW CONDITIONS WILL BE AFTER SEVERAL HOURS OF BLOWING/DRIFTING SNOW PRIOR TO THIS. WILL ISSUE AN SPS HIGHLIGHTING THIS HAZARD. TEMPERATURES WILL BE THE WARMEST IN SEVERAL DAYS...AND RANGE FROM THE LOWER 20S TO LOWER 30S. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 253 PM CST MON FEB 23 2015 A BIT OF A CHANGE IN THE UPPER FLOW PATTERN IS IN THE OFFING...WITH THE WESTERN RIDGE DRIFTING WEST OVER THE PACIFIC AND A CUT OFF LOW DEVELOPING OVER THE SOUTHWEST...SETTING UP SOMETHING MORE AKIN TO A SPLIT FLOW PATTERN AS THE WEEK GROWS LATE. THE NORTHERN STREAM STILL HOLDS SIGNIFICANT SWAY IN OUR AREA UNFORTUNATELY...AND THE IMPACT ON SENSIBLE WEATHER IS UNLIKELY TO BE SIGNIFICANT UNTIL LATE THIS WEEKEND OR EARLY NEXT WEEK. SATELLITE IMAGERY INDICATES A PATCH OF SOMEWHAT OPEN WATERS ON LAKE SUPERIOR ALONG A LAKE EFFECT FETCH FOR NORTH CENTRAL WISCONSIN...AND BREEZY SOUTHWEST WINDS IN THE SHORT TERM SHOULD KEEP THAT AREA FROM FREEZING OVER. THIS LEAVES POTENTIAL FOR LINGERING LAKE EFFECT FLURRIES OR SNOW SHOWERS TUESDAY NIGHT IN THE NORTH CENTRAL SNOW BELT...THOUGH ACCUMULATIONS SHOULD BE SLIGHT TO NIL. GUSTY WINDS WILL BE DIMINISHING THROUGH THE EVENING HOURS AS THE PRESSURE GRADIENT LOOSENS...BRINGING AN END TO POTENTIAL FOR BLOWING SNOW. ANOTHER BEEFY HIGH WILL FOLLOW IN TO GIVE US ANOTHER PLUNGE IN TEMPERATURES...BUT BEFORE THAT A SHORTWAVE WILL SHOOT THROUGH THE UPPER TROUGH. THE GEM STUBBORNLY BRINGS FLURRIES OR EXTREMELY LIGHT ACCUMULATIONS TO PORTIONS OF CENTRAL AND EAST CENTRAL WISCONSIN. THE REST OF THE GUIDANCE SHUNTS EVERYTHING WELL SOUTH OF THE AREA...AND THE FORECAST JOINS THAT CAMP IN KEEPING THINGS DRY HERE. THE MAIN STORY FOR THE SECOND HALF OF THE WORK WEEK...AGAIN...WILL BE SIGNIFICANTLY BELOW NORMAL TEMPS. THE COLD AIR REACHES ITS NADIR WEDNESDAY AFTERNOON INTO THURSDAY. HIGHS IN THE SINGLE DIGITS TO LOW/MID TEENS ARE EXPECTED WITH LOWS BELOW ZERO. WIND CHILL ADVISORIES MAY RETURN FOR ANOTHER SEQUEL...BUT THIS COLD PUSH DOES NOT LOOK TO MATCH PREVIOUS ITERATIONS...SO THERE IS LESS CONFIDENCE IN THAT AT THIS TIME. THE ARCTIC AIR MASS BEGINS TO MODERATE ON FRIDAY AND ESPECIALLY THIS WEEKEND...BUT TEMPERATURES STILL LOOK TO REMAIN BELOW NORMAL. HEADING INTO THE WEEKEND...AS A TROUGH DIGS OVER THE WEST COAST AND THE FLOW ALOFT BECOMES SOUTHWESTERLY. THIS FLOW WILL PUSH IN A SLUG OF MOISTURE FROM THE SOUTHERN PLAINS FOR THE SECOND HALF OF THE WEEKEND. MODELS ARE IN AGREEMENT SHOWING THE MOISTURE AND PUSH OF WARMER AIR. HOWEVER...THERE IS SPREAD IN HOW FAR NORTH THIS AIR GETS...WITH SIGNIFICANT IMPACTS ON SNOW POTENTIAL. THE CANADIAN HOLDS COLD AIR OVER THE GREAT LAKES AND SENDS YET ANOTHER WINTER STORM THROUGH THE MID-SOUTH AND FAR AWAY FROM OUR AREA. THE GFS AND ECMWF ARE MORE READY TO BRING A MORE SIGNIFICANT SYSTEM TOWARDS THE GREAT LAKES. AT THIS TIME IT AGAIN APPEARS THAT THE HIGHEST SNOWFALL TOTALS WILL MISS THE AREA. HOWEVER...IT IS POSSIBLE...GIVENT THE CURRENT GUIDANCE ENVELOPE...FOR ENOUGH SNOWFALL TO MEET ADVISORY CRITERIA IN CENTRAL AND EAST CENTRAL WISCONSIN. ULTIMATELY...THE MODEL SOLUTIONS ARE RELATIVELY FRAGILE THIS FAR OUT...AND THE BEST ADVICE IS TO FOLLOW UPDATED FORECASTS AS THE WEEK CONTINUES. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1134 AM CST MON FEB 23 2015 VFR CLEAR EXPECTED THROUGH THE EVENING AS CIRRUS SPREADS ACROSS THE REGION AHEAD OF THE NEXT CLIPPER. SOUTHWEST WINDS WILL INCREASE THROUGH THE AFTERNOON AND BECOME STRONG ENOUGH TO PRODUCE BLOWING AND DRIFTING SNOW THIS EVENING THROUGH TUESDAY MORNING. LIGHT SNOW WILL ARRIVE FROM NORTHWEST TO SOUTHEAST LATE TONIGHT AND CONTINUE THROUGH MIDDAY TUESDAY BEFORE DIMINISHING/EXITING. THOUGH THE SNOW WILL LIKELY DROP VSBYS TO IFR FOR A TIME...SNOW AMOUNTS SHOULD BE AROUND AN INCH OR LESS IN MOST PLACES. LOW LEVEL WIND SHEAR POSSIBLE TONIGHT WITH GUSTY SOUTHWEST SURFACE WINDS AND SOUTHWEST WINDS OF 40 KNOTS AT 1200 FT AGL. FIELD CREWS MAY BE NEEDED TO CLEAR SNOW DRIFTS FROM RUNWAYS, TAXIWAYS AND RAMPS TONIGHT. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......LUCHS AVIATION.......MPC