Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/01/15


AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
1057 PM PST MON DEC 29 2014 ...WINDY AND COLDER WEATHER ON THE WAY FOR THE END OF 2014... .SYNOPSIS...A FAST MOVING STORM SYSTEM WILL MOVE SOUTHEAST ACROSS NEVADA TONIGHT BRINGING A SLIGHT CHANCE OF SHOWERS MAINLY IN THE HILLS. COLDER AND WINDIER CONDITIONS WILL SETTLE OVER THE AREA TUESDAY AND WEDNESDAY BEHIND THIS SYSTEM. A WARMING TREND WILL RETURN BY LATE THIS WEEK. && .DISCUSSION...AS OF 9:00 PM PST MONDAY...A COLD UPPER LEVEL LOW OVER SOUTHEAST OREGON WILL DRIVE SOUTHEAST DURING THE NIGHT WITH THE TROUGH AXIS MOVING THROUGH THE AREA LATE TONIGHT. THE SYSTEM HAS VERY LITTLE MOISTURE BUT RECENT HRRR MODEL RUNS HAVE SHOWN ISOLATED CONTOURS OF ONE TO TWO-HUNDREDTHS OF PRECIP IN THE HILLS. A SLIGHT CHANCE OF SHOWERS IS IN THE FORECAST FOR TONIGHT BUT MOST LIKELY ANY PRECIP WILL FALL OVER THE HILLS. WINDS WILL INCREASE AS THIS TROUGH AXIS MOVES THROUGH WITH MODELS SHOWING 925 MB WINDS INCREASING TO 35-45 KT RANGE TUESDAY MORNING. MODELS ALSO SHOW DECENT OMEGA VALUES AFTER THE TROUGH PASSES INDICATING THAT WINDS ALOFT COULD MIX DOWN TO THE SURFACE. THEREFORE A WIND ADVISORY IS IN EFFECT BEGINNING TUESDAY MORNING IN THE NORTH AND EAST BAY HILLS AND SANTA CRUZ MOUNTAINS FOR GUSTS UP TO 55-60 MPH...AND MIDDAY TUESDAY FOR THE REST OF THE SFO BAY AREA WITH GUSTS TO 40-45 MPH. STRONG WINDS WILL CONTINUE THROUGH TUESDAY NIGHT AND MAY EVEN BE SLIGHTLY STRONGER THAN TUESDAY MORNING. THESE STRONG WINDS WILL BRING DOWN SOME TREES AND CAUSE POWER OUTAGES AS THE SOIL REMAINS FAIRLY WET FROM RAINS EARLIER THIS MONTH. WINDS WILL DECREASE BY MIDDAY WEDNESDAY AS THE LOW MOVES FURTHER EAST AND AN UPPER LEVEL RIDGE BUILDS IN FROM THE WEST. COLD NORTHERLY FLOW WILL CONTINUE OVER THE AREA THROUGH WEDNESDAY AND WITH THE WINDS DIMINISHING IT WILL SET UP A COLD NIGHT FOR NEW YEARS EVE. TEMPERATURES WILL DROP INTO THE 20S IN MANY OF THE INLAND VALLEYS WITH LOWER TO MID 30S IN THE URBAN AREAS AROUND OAKLAND-SAN JOSE. A FROST ADVISORY MAY BE NEEDED FOR MOST OF THE SFO BAY AREA WEDNESDAY NIGHT. TEMPERATURES WILL SLOWLY WARM UP THURSDAY THROUGH SUNDAY AS THE UPPER LEVEL RIDGE MOVES OVER THE WEST COAST. IN THE LONG RANGE...MODELS CONTINUE TO STRUGGLE WITH WHETHER THERE WILL BE RAIN IN OUR CWA AROUND THE MIDDLE OF NEXT WEEK. LATEST GFS AND ECMWF INDICATE A CHANCE FOR RAIN FOR AT LEAST THE NORTHERN PART OF THE DISTRICT. && .AVIATION...AS OF 10:45 PM PST MONDAY...THE LIMITED BAND OF LOW AND MID LEVEL CLOUDINESS ASSOCIATED WITH THE MOSTLY DRY COLD FRONT SWEEPING SOUTHWARD THROUGH CENTRAL CALIFORNIA IS NOW PASSING THROUGH THE MONTEREY BAY REGION. BEHIND IT SKIES ARE EXPECTED TO REMAIN MOSTLY CLEAR THROUGH THE NIGHT...AS THE BOUNDARY LAYER AIR MASS LOOKS TO REMAIN SUFFICIENTLY DRY AND WELL MIXED AS TO PRECLUDE ANY DEVELOPMENT OF FOG OR LOW CLOUDS. ON TUESDAY HOWEVER...COUPLING OF A RAPIDLY INCREASING NORTH TO SOUTH PRESSURE GRADIENT WITH STRONG NORTH-TO-NORTHEAST FLOW ALOFT WILL RESULT IN INCREASINGLY STRONG WINDS OVER THE DISTRICT. KEY QUESTIONS ARE WHEN...WHERE...AND TO WHAT DEGREE THESE WILL MIX DOWN TO THE SURFACE AT LOW ELEVATIONS. HIGH RESOLUTION LOCAL MODEL OUTPUT INDICATES THIS WILL IN FACT PROGRESSIVELY OCCUR AT SFO BAY AREA TAF SITES DURING THE DAY ON TUESDAY...WITH WINDS LIKELY BECOMING LOCALLY STRONG AND GUSTY BY AFTERNOON. VICINITY OF KSFO...MOSTLY CLEAR SKIES THROUGH THE REMAINDER OF THE NIGHT AND ALL DAY ON TUESDAY AS THE POST-FRONTAL AIR MASS REMAINS DRY AND WELL MIXED. WINDS VEER NORTH-NORTHEASTERLY TOMORROW AND ARE LIKELY TO BECOME STRONG AND GUSTY BY AFTERNOON. MEDIUM-TO-HIGH CONFIDENCE. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WITH GENERALLY LIGHT WINDS THROUGH THE PERIOD. MEDIUM CONFIDENCE. && .MARINE...AS OF 01:38 PM PST MONDAY...STRONG HIGH PRESSURE WILL BUILD OVER THE GREAT BASIN INCREASING NORTHERLY WINDS THROUGH WEDNESDAY. WINDS DECREASE WEDNESDAY NIGHT AND THURSDAY AS THE HIGH WEAKENS. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...SCA...PIGEON PT TO PT PINOS 0-10 NM SCA...PIGEON PT TO PT PINOS 10-60 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 3 AM SCA...PT ARENA TO PT REYES 0-10 NM SCA...PT ARENA TO PT REYES 10-60 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...PT REYES TO PIGEON PT 10-60 NM && $$ PUBLIC FORECAST: W PI AVIATION/MARINE: BLIER 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 RENO NV
936 PM PST MON DEC 29 2014 .UPDATE... JUST A FEW MINOR FORECAST TWEAKS THIS EVENING. WE ARE STILL ON TRACK FOR A LIGHT SNOWFALL LATER TONIGHT. HOWEVER, THE INITIAL BAND ASSOCIATED WITH SHALLOWER LIFT/MOISTURE HAS MOVED TO BETWEEN RENO AND CARSON CITY AND IS NOT THE MAIN BAND OF SNOW FOR THE AREA. THE MAIN EVENT FOR THE RENO-SPARKS AND CARSON CITY-MINDEN AREAS LOOKS TO BE LATER TONIGHT AS THE MAIN UPPER COLD POOL/TROUGH AXIS APPROACHES. THIS IS EVIDENCED BY INCREASING RADAR RETURNS UP AROUND PYRAMID LAKE AND COLDER CLOUD TOPS IN THE INFRARED SATELLITE NORTH OF RENO. ALONG WITH A LIGHT SNOWFALL FOR MOST OF WESTERN NEVADA, THE INSTABILITY AND DEEPER MOISTURE WITH THE COLD POOL SHOULD COMBINE WITH UPSLOPE FLOW AGAINST THE CARSON RANGE TO PRODUCE LOCALLY HIGHER SNOWFALL TOTALS IN THE FOOTHILLS SOUTH AND WEST OF RENO. SNYDER && .SYNOPSIS... A STRONG COLD FRONT WILL PUSH THROUGH THE AREA TONIGHT. SNOWFALL IS POSSIBLE WITH POTENTIAL TRAVEL IMPACTS FOR THE TUESDAY MORNING COMMUTE ALONG THE HIGHWAY 395 CORRIDOR. STRONG WINDS ARE EXPECTED TO PRODUCE ROUGH CONDITIONS ON AREA LAKES ALONG WITH POSSIBLE AREAS OF BLOWING SNOW. TEMPERATURES WILL BE BITTER COLD WITH WIND CHILLS IN THE SINGLE DIGITS AND NEGATIVE VALUES HEADING INTO THE NEW YEAR. A MILDER PATTERN WILL RETURN FOR THE WEEKEND. && .PREVIOUS DISCUSSION... /ISSUED 242 PM PST MON DEC 29 2014/ SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT VISIBLE SATELLITE IMAGERY SHOWING A COLD UPPER LOW ACROSS THE PACIFIC NORTHWEST WITH COOLING IR COLD TOPS ALONG A STRONG COLD FRONT OVER SOUTHERN OREGON. THIS FRONT WILL QUICKLY DRIVE SOUTH THROUGH NORTHERN NEVADA TONIGHT INTO TUESDAY MORNING PROVIDING THE POTENTIAL FOR A FEW INCHES OF SNOWFALL AND BITTER COLD HEADING INTO THE NEW YEAR. HI-RES MESOSCALE AND GLOBAL MODELS ARE BEGINNING TO CLUE INTO THE FORMATION OF BANDED SNOWFALL CREATED BY STRONG LOW LEVEL FRONTOGENESIS AND MOISTURE IN A REGION OF FAVORABLE MICROPHYSICS FOR ICE CRYSTAL GROWTH. THESE COLD TEMPERATURES WILL MAKE FOR LIGHT AND FLUFFY SNOW. SOME DISAGREEMENT ON TIMING BUT LARGELY LOOKING FOR SNOWFALL IN THE RENO/CARSON CITY REGION AS EARLY 8PM BUT THE MOST FAVORABLE WINDOW LOOKS TO BE BETWEEN 10PM-4AM. A WINTER WEATHER ADVISORY HAS BEEN POSTED FOR THE SIERRA FRONT WHICH INCLUDES THE HWY 395 CORRIDOR SOUTH THROUGH MINDEN AND GARDNERVILLE. THE ADVISORY ALSO COVERS PORTIONS OF WESTERN MINERAL AND SOUTHERN LYON COUNTY. GENERALLY LOOKING FOR SNOWFALL IN THE 1-2" RANGE FROM RENO TO CARSON CITY WITH HIGHER AMOUNTS SOUTH WHERE UPSLOPE FORCING WILL ADD ADDITIONAL LIFT. LOCATIONS ALONG THE EASTERN SLOPES OF THE CARSON RANGE, EASTERN ALPINE CO, NORTHERN MONO COUNTY COULD SEE MORE IN THE 2-4" RANGE. SLIDERS ARE NOTORIOUSLY DIFFICULT SYSTEMS TO FORECAST SO WILL PUT FORECAST CONFIDENCE IN SNOW AMOUNTS IN THE MEDIUM CATEGORY. THE OTHER IMPACTS WITH THIS SYSTEM WILL BE SOME GUSTY CONDITIONS BEHIND THE FRONT AS A STRONG PRESSURE GRADIENT DEVELOPS ACROSS WESTERN NEVADA AND THE SIERRA. EXPECTING TO SEE SUSTAINED WINDS IN THE 15-25 MPH RANGE WITH GUSTS UP TO 40-45 MPH OUT OF THE EAST WHICH PUTS THIS JUST BELOW ADVISORY CRITERIA ACROSS WESTERN NEVADA. HAVE HOWEVER POSTED A LAKE WIND ADVISORY FOR PYRAMID LAKE AND A WIND ADVISORY ACROSS THE TAHOE BASIN. EXPECTING HAZARDOUS BOATING CONDITIONS ON AREA LAKES WITH GUSTS NEAR 45 MPH EXPECTED IN THE TAHOE BASIN WITH HIGHEST WAVES ALONG THE ATYPICAL WESTERN SHORES. WINDS WILL SHARPLY INCREASE IN ELEVATION WITH VERY STRONG WINDS EXPECTED MAINLY ABOVE 8,500 FEET WHERE GUSTS BETWEEN 80-100+ MPH ARE POSSIBLE. THIS MAY ALSO POSE THE RISK FOR TREE FALLS ACROSS THE TAHOE BASIN PARTICULARLY FOR TREES WEAKENED FROM THE PAST WIND EVENT. THE SAME STRONG WINDS HOLD TRUE ACROSS HIGH TERRAIN THROUGH MONO COUNTY BUT THE STRONGEST WINDS WILL REMAIN OVER THE CREST AND ALONG THE WESTERN SLOPES OF THE SIERRA WHERE VERY STRONG DOWNSLOPE WINDS LOOK FAVORABLE. OTHERWISE, LOOKING FOR SNOW SHOWERS TO LINGER THROUGH TUESDAY AFTERNOON ESPECIALLY ACROSS ALPINE AND MONO COUNTY WHERE UPSLOPE FORCING SETS UP. AN INCH OR TWO IS POSSIBLE ACROSS THE TAHOE BASIN AND MONO COUNTY OUTSIDE OF AREAS OF LAKE ENHANCED SNOWFALL. STRONG WINDS MAY ALSO PRODUCE AREAS OF BLOWING SNOW AND REDUCED VISIBILITY. FUENTES (WEDNESDAY AND THURSDAY).. MAIN CHANGE TO THE WEDNESDAY-THURSDAY TIME FRAME WAS LOWERING MAX AND MIN TEMPS BY A FEW DEGREES EACH, WITH THE INCREASED EXPECTATION OF ACCUMULATING SNOW WITH THE UPPER LOW PASSING THROUGH TONIGHT AND TUESDAY. THE PRESENCE OF SNOW COVER WILL STRENGTHEN THE VALLEY INVERSION FURTHER AND KEEP HIGHS ONLY IN THE LOWER-MID 20S WEDNESDAY. STRONG NE-E WINDS WILL CONTINUE OVER THE SIERRA RIDGES WITH GUSTS 75-85 MPH, WHILE SURFACE WIND GUSTS WILL GENERALLY RANGE FROM 25-35 MPH EXCEPT NEAR 40 MPH AROUND TAHOE WEDNESDAY MORNING. THESE WINDS WILL DECREASE LATER IN THE DAY AS THE UPPER LOW MOVES FROM SOUTHEAST CA TO ARIZONA. NEW YEARS EVE WILL BE QUITE COLD WITH TEMPERATURES BY MIDNIGHT DROPPING TO THE LOWER TEENS FOR RENO-CARSON CITY AND SINGLE DIGITS AROUND TAHOE. ALTHOUGH WINDS WILL BE DECREASING, WIND CHILLS COULD STILL BE NEAR ZERO FOR WESTERN NV AND -10 DEGREES IN THE TAHOE BASIN FOR THE FIRST COUPLE HOURS OF 2015. THE EARLY MORNING LOWS FOR NEW YEARS DAY ARE LIKELY TO BE AROUND 5 DEGREES FOR URBAN AREAS OF WESTERN NV, AND BELOW ZERO AWAY FROM THE MAIN CITIES AND IN THE SIERRA VALLEYS. ON THURSDAY, THE CORE OF THE COLD AIR MASS WILL MOVE AWAY FROM WESTERN NV BUT WITH INVERSION STILL IN PLACE, HIGHS ARE LIKELY TO REMAIN BELOW FREEZING. LIGHTER WINDS ARE EXPECTED WITH DRY CONDITIONS PREVAILING THROUGH THE FIRST DAY OF 2015. MJD LONG TERM (FRIDAY-MONDAY)... THE MOTTO FOR THE LONG TERM WILL BE "WELCOME TO INVERSION CITY". GUIDANCE CONSENSUS SHOWS RIDGING JUST OFF THE WEST COAST THROUGH THE WEEKEND WHICH YIELDS WARMING TEMPERATURES AT 700MB. COUPLED WITH A SURFACE HIGH OVER THE INTERMOUNTAIN WEST THIS RESULTS IN AN INVERSION PATTERN FOR THE VALLEYS OF WESTERN NV AND NORTHEAST CA, WITH LIGHT WINDS, LIMITED MIXING, AND POTENTIAL AIR POLLUTION BUILDUPS. TEMPERATURES IN VALLEYS WILL WARM EACH DAY BUT AT A MUCH SLOWER RATE COMPARED TO THE MOUNTAINS. IF WE GET SUFFICIENT SNOWFALL TONIGHT THEN THOSE INVERSIONS COULD BE STRONGER WITH POTENTIAL FOR SPOTS OF FREEZING FOG IN NORMALLY PRONE AREAS. UNFORTUNATELY I`M REALLY NOT SEEING MEANINGFUL STORM POTENTIAL THROUGH AT LEAST MONDAY AS THE RIDGE BLOCKS PACIFIC STORMS FROM IMPACTING CA/NV. THERE ARE SOME SIGNS OF THE RIDGE BREAKING DOWN OR BEING UNDERCUT MID/LATE NEXT WEEK ALLOWING AN INCREASED CHANCE OF ATMOSPHERIC RIVERS LANDFALLING ON THE WEST COAST. BUT OF COURSE PREDICTABILITY OF THESE PATTERN CHANGES 7-10 DAYS OUT IS QUITE LIMITED. CS AVIATION... FORECAST CONFIDENCE IN TODAY`S TAFS IS MEDIUM, WITH UNCERTAINTIES IN TIMING AND INTENSITY OF TONIGHT`S BAND OF SNOW. THESE KIND OF SLIDER STORMS ARE A CHALLENGE TO PREDICT SO SNOWFALL POTENTIAL REMAINS ONLY MEDIUM CONFIDENCE AS WELL. HIGH RESOLUTION SIMULATIONS (HRRR) ARE SHOWING A FAST MOVING BAND OF -SN DEVELOPING FROM AAT-LOL AROUND SUNDOWN AND THEN DROPPING SOUTHWARD INTO RNO/CXP 4-10Z, TRK/TVL/MEV AROUND 6-12Z, AND AFTER 12Z AT MMH. IN SUCH A STRONGLY FORCED SITUATION THE HRRR USUALLY DOES REASONABLY WELL SO WE`LL FOLLOW FOR THE TAFS. PERIODS OF MVFR/IFR -SN LIKELY AT RNO/CXP/TRK/TVL/MEV TONIGHT YIELDING UP TO 2 INCHES OF FLUFFY SNOW. THERE`S ABOUT A 20% CHANCE WE COULD SEE BRIEF PERIODS OF HEAVIER SNOW, 1/2SM VISIBILITY TYPE STUFF, BUT PREDICTING TIMING ON THAT IS TRICKY. GUSTY N/NE WINDS WILL RESULTING IN BLOWING SNOW AS WELL. CLOUDS WILL RESULT IN TERRAIN OBSCURATION TONIGHT THROUGH TOMORROW. THE POST-FRONTAL NORTHEAST WINDS TUESDAY WILL BE PRONOUNCED AND GUSTY, WITH A FRESH SUSTAINED 15-25 KTS EAST/NORTHEAST WIND WITH GUSTS 25-30 KTS. CXP WHICH IS PRONE TO NE FLOW EVENTS, WILL LIKELY SEE PERIODS OF STRONGER SUSTAINED WINDS. RIDGE LEVEL GUSTS OF 60-70 KTS FORECAST TOMORROW, INCREASING TUESDAY NIGHT INTO WEDNESDAY. DUE TO THE UNUSUAL NE WIND DIRECTION, THAT WILL LEAD TO TURBULENCE ESPECIALLY WEST OF ANY MOUNTAINS DUE TO MOUNTAIN WAVE ACTIVITY. CS && .REV WATCHES/WARNINGS/ADVISORIES... NV...LAKE WIND ADVISORY FROM 7 AM TO 7 PM PST TUESDAY FOR PYRAMID LAKE IN NVZ004. WIND ADVISORY FROM 7 AM TUESDAY TO 4 AM PST WEDNESDAY NVZ002. WINTER WEATHER ADVISORY UNTIL 4 PM PST TUESDAY NVZ001. WINTER WEATHER ADVISORY UNTIL 10 AM PST TUESDAY NVZ003. CA...WIND ADVISORY FROM 7 AM TUESDAY TO 4 AM PST WEDNESDAY CAZ072. && $$ FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT... HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
919 PM PST MON DEC 29 2014 ...WINDY AND COLDER WEATHER ON THE WAY FOR THE END OF 2014... .SYNOPSIS...A FAST MOVING STORM SYSTEM WILL MOVE SOUTHEAST ACROSS NEVADA TONIGHT BRINGING A SLIGHT CHANCE OF SHOWERS MAINLY IN THE HILLS. COLDER AND WINDIER CONDITIONS WILL SETTLE OVER THE AREA TUESDAY AND WEDNESDAY BEHIND THIS SYSTEM. A WARMING TREND WILL RETURN BY LATE THIS WEEK. && .DISCUSSION...AS OF 9:00 PM PST MONDAY...A COLD UPPER LEVEL LOW OVER SOUTHEAST OREGON WILL DRIVE SOUTHEAST DURING THE NIGHT WITH THE TROUGH AXIS MOVING THROUGH THE AREA LATE TONIGHT. THE SYSTEM HAS VERY LITTLE MOISTURE BUT RECENT HRRR MODEL RUNS HAVE SHOWN ISOLATED CONTOURS OF ONE TO TWO-HUNDREDTHS OF PRECIP IN THE HILLS. A SLIGHT CHANCE OF SHOWERS IS IN THE FORECAST FOR TONIGHT BUT MOST LIKELY ANY PRECIP WILL FALL OVER THE HILLS. WINDS WILL INCREASE AS THIS TROUGH AXIS MOVES THROUGH WITH MODELS SHOWING 925 MB WINDS INCREASING TO 35-45 KT RANGE TUESDAY MORNING. MODELS ALSO SHOW DECENT OMEGA VALUES AFTER THE TROUGH PASSES INDICATING THAT WINDS ALOFT COULD MIX DOWN TO THE SURFACE. THEREFORE A WIND ADVISORY IS IN EFFECT BEGINNING TUESDAY MORNING IN THE NORTH AND EAST BAY HILLS AND SANTA CRUZ MOUNTAINS FOR GUSTS UP TO 55-60 MPH...AND MIDDAY TUESDAY FOR THE REST OF THE SFO BAY AREA WITH GUSTS TO 40-45 MPH. STRONG WINDS WILL CONTINUE THROUGH TUESDAY NIGHT AND MAY EVEN BE SLIGHTLY STRONGER THAN TUESDAY MORNING. THESE STRONG WINDS WILL BRING DOWN SOME TREES AND CAUSE POWER OUTAGES AS THE SOIL REMAINS FAIRLY WET FROM RAINS EARLIER THIS MONTH. WINDS WILL DECREASE BY MIDDAY WEDNESDAY AS THE LOW MOVES FURTHER EAST AND AN UPPER LEVEL RIDGE BUILDS IN FROM THE WEST. COLD NORTHERLY FLOW WILL CONTINUE OVER THE AREA THROUGH WEDNESDAY AND WITH THE WINDS DIMINISHING IT WILL SET UP A COLD NIGHT FOR NEW YEARS EVE. TEMPERATURES WILL DROP INTO THE 20S IN MANY OF THE INLAND VALLEYS WITH LOWER TO MID 30S IN THE URBAN AREAS AROUND OAKLAND-SAN JOSE. A FROST ADVISORY MAY BE NEEDED FOR MOST OF THE SFO BAY AREA WEDNESDAY NIGHT. TEMPERATURES WILL SLOWLY WARM UP THURSDAY THROUGH SUNDAY AS THE UPPER LEVEL RIDGE MOVES OVER THE WEST COAST. IN THE LONG RANGE...MODELS CONTINUE TO STRUGGLE WITH WHETHER THERE WILL BE RAIN IN OUR CWA AROUND THE MIDDLE OF NEXT WEEK. LATEST GFS AND ECMWF INDICATE A CHANCE FOR RAIN FOR AT LEAST THE NORTHERN PART OF THE DISTRICT. && .AVIATION...AS OF 4:45 PM PST MONDAY...PATCHES OF LOW AND MID LEVEL CLOUDINESS REMAIN OVER PORTIONS OF THE DISTRICT BUT WITH ALL TERMINALS NOW REPORTING VFR CONDITIONS. THESE SHOULD CONTINUE THROUGH THE NIGHT AS THE BOUNDARY LAYER AIR MASS LOOKS TO REMAIN SUFFICIENTLY DRY AND WELL MIXED AS TO PRECLUDE DEVELOPMENT OF EITHER FOG OR CIGS. THE PASSAGE OF A STRONG BUT DRY UPPER LEVEL DISTURBANCE FROM THE NORTH TONIGHT...IN CONJUNCTION WITH DEVELOPMENT OF A STRONG NE TO SW ORIENTED SEA LEVEL PRESSURE GRADIENT...WILL RESULT IN INCREASINGLY STRONG NORTH TO NORTHEASTERLY FLOW ALOFT OVER THE AREA. KEY QUESTIONS ARE WHEN...WHERE...AND TO WHAT DEGREE THESE WINDS MIX DOWN TO THE SURFACE. HIGH RESOLUTION LOCAL MODEL OUTPUT INDICATES THIS WILL PROGRESSIVELY OCCUR AT SFO BAY AREA TAF SITES DURING THE DAY ON TUESDAY...WITH WINDS POTENTIALLY BECOMING LOCALLY STRONG AND GUSTY BY AFTERNOON. VICINITY OF KSFO...NO MORE THAN SCATTERED CLOUDINESS IS EXPECTED OVERNIGHT AND TUESDAY MORNING AS THE AIR MASS REMAINS DRY AND WELL MIXED. WINDS VEER NORTH-NORTHEASTERLY TOMORROW AND ARE LIKELY TO BECOME STRONG AND GUSTY BY AFTERNOON. MEDIUM CONFIDENCE. KSFO BRIDGE APPROACH...SIMILAR TO KSFO. MONTEREY BAY AREA TERMINALS...VFR CONDITIONS WITH GENERALLY LIGHT WINDS THROUGH THE PERIOD. MEDIUM CONFIDENCE. && .MARINE...AS OF 01:38 PM PST MONDAY...STRONG HIGH PRESSURE WILL BUILD OVER THE GREAT BASIN INCREASING NORTHERLY WINDS THROUGH WEDNESDAY. WINDS DECREASE WEDNESDAY NIGHT AND THURSDAY AS THE HIGH WEAKENS. && .MTR WATCHES/WARNINGS/ADVISORIES... .TNGT...SCA...PT PINOS TO PT PIEDRAS BLANCAS 10-60 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...PT REYES TO PIGEON PT 10-60 NM SCA...PT ARENA TO PT REYES 0-10 NM SCA...PT ARENA TO PT REYES 10-60 NM SCA...PIGEON PT TO PT PINOS 10-60 NM SCA...PT REYES TO PIGEON PT 0-10 NM SCA...PIGEON PT TO PT PINOS 0-10 NM && $$ PUBLIC FORECAST: W PI AVIATION: BLIER MARINE: AC 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 MIAMI FL
430 PM EST TUE DEC 30 2014 ...VERY WARM, HUMID PATTERN TO CONTINUE INTO THE NEW YEAR... .UPDATE...SEA BREEZES HAVE DEVELOPED ALONG BOTH THE GULF AND ATLANTIC COASTS THIS AFTERNOON...CLEARLY SEEN IN VISIBLE SATELLITE IMAGERY. PRETTY RARE FOR WINTERTIME! ENOUGH LOW LEVEL MOISTURE IS PRESENT TO HAVE CU FORMING ALONG THE SEA BREEZE FRONTS, BUT NOT QUITE ENOUGH TO GET SHOWERS GOING. HRRR IS OVERDOING QPF AS RADAR CONTINUES TO SHOW NO SHOWER ACTIVITY (ECHOES SOUTH OF LAKE OKEECHOBEE ARE REFLECTIVE OF SUGARCANE BURNING). AS DAYTIME HEATING IS LOSS, IT LOOKS LIKE CONDITIONS WILL REMAIN DRY THROUGH TONIGHT...BUT AS THE WEAKENING COLD FRONT OVER CENTRAL FLORIDA SAGS SOUTHWARD, SOME CONVERGENCE ALONG THE PALM BEACH COAST COULD ALLOW FOR A FEW SHOWERS TO DEVELOP THERE LATER TONIGHT...SO KEPT SHOWER MENTION IN THERE ONLY. SOUTH FL CONTINUES WITH ABOVE NORMAL TEMPS ALONG WITH HUMIDITY...AND THIS WILL CONTINUE INTO THE WEEKEND AND EARLY NEXT WEEK! A RECORD HIGH OF 83F WAS TIED AT MIAMI TODAY. THE HOTTEST READINGS WERE FROM OPA LOCKA (KOPF) TO PEMBROKE PINES (KHWO) TO WEST PALM BEACH (KPBI) WHERE HIGHS OFFICIALLY REACHED 85F, THE WARMEST IN THE COUNTRY (FOR MAJOR REPORTING STATIONS/SOME UPPER 80S WERE REGISTERED BY MESONETS OVER PORTIONS OF INTERIOR SOUTH FL THIS AFTERNOON). THE WARM PATTERN WILL CONTINUE WITH POSSIBLY BUILDING HEAT BY THIS WEEKEND. ECMWF INDICATES MAX TEMPS INTO THE MID-UPPER 80S EAST COAST METRO WITH DEWPOINTS INTO THE LOWER 70S EQUATING TO HEAT INDICES INTO THE LOWER 90S! GFS AND MODEL BLENDS OFFER SLIGHTLY COOLER READINGS...AND THAT`S WHAT OUR CURRENT FORECAST REFLECTS. HOWEVER, WE VERY WELL MAY NEED TO INCREASE OUR HIGHS PROJECTED FOR THIS UPCOMING WEEKEND. A POSSIBLE "MINI-HEAT WAVE" TO START 2015. /GREGORIA && .PREV DISCUSSION... /ISSUED 247 PM EST TUE DEC 30 2014/ SHORT TERM (TONIGHT-NEW YEARS` DAY)... A MOSTLY ZONAL UPPER FLOW PATTERN WILL CONTINUE ACROSS SOUTH FLORIDA THROUGH NEW YEARS` DAY AS A STRONG RIDGE REMAINS ACROSS CUBA AND THE BAHAMA ISLANDS. A WEAK COLD FRONT CURRENTLY IN NORTH CENTRAL FLORIDA WILL OOZE INTO SOUTH FLORIDA TONIGHT AND WEDNESDAY BEFORE STALLING AND RAPIDLY BECOME DIFFUSE. THERE WILL BE SOME CLOUDS WITH THE FRONTAL BOUNDARY BUT VERY LITTLE IN THE WAY OF RAINFALL AS DEEP LAYER MOISTURE WILL BE LACKING. THERE IS SOME POTENTIAL FOR FOG AGAIN OVER THE INTERIOR AHEAD OF THE FRONT. HOWEVER, EXTENSIVE CLOUD COVER WILL LIKELY HAMPER FOG DEVELOPMENT AND WILL LEAVE OUT OF FORECAST AT THIS TIME WITH THE SREF ONLY SHOWING A 30-40% CHANCE OF VISIBILITY LOWERING LESS THAN THREE MILES. DUE TO THE LACK OF PUSH WITH THIS FRONT, THE STRONG SUBSIDENCE CAP CURRENTLY OVER SOUTH FLORIDA WILL BE SLOW TO ERODE WITH FORECAST SOUNDINGS ONLY INDICATING SOME INSTABILITY BY LATE WEDNESDAY AND EVEN THEN A PWAT OF ONLY AROUND 1.3". LONG TERM (FRIDAY-TUESDAY)... NOT MANY CHANGES SEEN TO THE UPPER FLOW PATTERN IN THE EXTENDED PERIOD AS THE SUBTROPICAL RIDGE REMAINS FIRMLY ENTRENCHED IN ITS POSITION ACROSS THE BAHAMA ISLAND CHAIN. AT THE SURFACE, WHAT IS LEFT OF THE FRONTAL BOUNDARY WILL LIFT BACK TO THE NORTH WEDNESDAY NIGHT OR THURSDAY. THIS IS IN RESPONSE TO A POWERFUL TROUGH CURRENTLY DEEPENING INTO THE FOUR CORNERS AREA THAT WILL MOVE INTO THE CENTRAL/SOUTHERN PLAINS ON FRIDAY NIGHT AND SATURDAY THEN INTO THE GREAT LAKES AND NEW ENGLAND THIS WEEKEND. A COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL THEN MOVE INTO NORTH FLORIDA ON SUNDAY WHERE IT WILL STALL INTO EARLY NEXT WEEK. SO THESE TWO PARAGRAPHS SPELL OUT A WARM AND GENERALLY DRY PATTERN FOR SOUTH FLORIDA TO END THIS YEAR AND THE BEGINNING OF THE NEW YEAR. MARINE... GOOD BOATING CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD WITH A LIGHT WIND EXPECTED AND SEAS 4 FEET OR LESS. THE PRESSURE GRADIENT WILL REMAIN WEAK AS THE COLD FRONT BECOMES DIFFUSE AND THEN SLOWLY LIFTS TO THE NORTH TOWARDS THE END OF THE WEEK. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 69 79 68 78 / 20 40 20 20 FORT LAUDERDALE 70 80 69 79 / 10 30 20 20 MIAMI 70 81 69 80 / 10 20 10 20 NAPLES 66 79 65 79 / 10 20 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
300 PM EST TUE DEC 30 2014 .UPDATE (REST OF TODAY THROUGH WEDNESDAY)... 20Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW MUCH OF THE NATION UNDER A BROAD LONGWAVE TROUGH. THE MOST ENERGETIC FEATURE WITHIN THIS TROUGH IS A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE INTERMOUNTAIN WEST WHICH IS PROGGED BY ALL THE NUMERICAL GUIDANCE TO BECOME A LARGE CUTOFF LOW OVER THE SOUTHWESTERN STATES BEFORE EJECTING EASTWARD ACROSS THE SOUTHERN/CENTRAL PLAINS LATER IN THE WEEK. OUR FORECAST AREA RESIDES WITHIN A ZONE OF DEEP LAYER SOUTHWEST FLOW BETWEEN THE LONGWAVE TROUGH AND AND WEST-EAST ORIENTED RIDGE ACROSS THE NORTHWEST CARIBBEAN. A PLUME OF SOUTHERN STREAM MOISTURE IS STILL IN WV IMAGERY RIDGING THIS FLOW OVER THE EASTERN GULF OF MEXICO AND FL PENINSULA. AT THE SURFACE...A WEAK COLD FRONT IS NOW ALIGNED ACROSS THE CENTRAL FLORIDA PENINSULA AND IS MAKING VERY SLOW PROGRESS SOUTHWARD. REGIONAL RADARS SHOW A SWATH OF LIGHT SHOWERS AND AREAS OF DRIZZLE ALONG AND NOW BEHIND THIS BOUNDARY. THIS TRANSITION FROM A KATAFRONT TO AN ANAFRONT CONFIGURATION HAS HELPED KEEP THE RAIN ACROSS MANY OF THE SAME PLACES SO FAR TODAY...EVEN THROUGH THE FRONT ITSELF HAS MADE STEADY PROGRESS TO THE SOUTH SINCE EARLY THIS MORNING. && .SHORT TERM (REST OF TODAY THROUGH WEDNESDAY)... REST OF TODAY...THE FRONT STILL LOOKS TO SLOWLY SETTLE SOUTH TO NEAR PUNTA GORDA AROUND SUNSET. THE ORGANIZATION AND COVERAGE OF SHOWERS HAS DIMINISHED SOMEWHAT IN THE PAST COUPLE OF HOURS AS THE WEAK SHORTWAVE TO OUR NORTH IS NOW PASSING BY. HOWEVER...THE LOW LEVEL BOUNDARY FOCUS WILL STILL KEEP THE CHANCE FOR MORE SCT SHOWERS IN THE FORECAST...GENERALLY SOUTH OF HERNANDO COUNTY AND TO THE NORTH OF THE SARASOTA TO PUNTA GORDA REGION. ALSO WITH THE FLOW BECOMING MORE AND MORE PARALLEL TO THE FRONT...THE ACTUALLY BOUNDARY PASSAGE WILL NOT NECESSARILY END THE CHANCE FOR RAIN. MANY OF THE GUIDANCE MEMBERS WERE INDICATING THE BOUNDARY TAKING ON AN INCREASINGLY ANAFRONT CONFIGURATION WHERE BETTER CHANCES FOR THE CLOUDS AND SHOWERS ARE ACTUALLY ALONG AND BEHIND THE BOUNDARY. THIS APPEARS TO BE TAKING SHAPE THIS AFTERNOON AS THE FRONT IS NOW DOWN SOUTH OF THE TAMPA BAY/POLK COUNTY REGION...AND YET MUCH OF THE LIGHT SHOWERS/DRIZZLE ARE STILL REMAINS ALONG THE GENERAL I-4 CORRIDOR. FOR OUR FAR NORTHERN ZONES...THE RAIN IS OVER AND DRIER AIR WILL CONTINUE TO SETTLE BEHIND THE FRONT THROUGH EARLY THIS EVENING. FOR OUR FAR SOUTHERN ZONES...WELL...THE WITH THE FRONT BECOMING MORE ANAFRONT WITH TIME...THE SHOWERS SOUTHWARD MARCH AS SLOWED TO A CRAWL. EVENTUALLY A FEW SHOWERS/PATCHES OF DRIZZLE SHOULD MAKE IT DOWN TO SARASOTA/PUNTA GORDA AND FORT MYERS...BUT IS LOOKING MORE LIKELY TO BE TONIGHT THAN DURING THE ACTUAL DAYLIGHT HOURS TODAY. TONIGHT AND WEDNESDAY...THE FRONT STALLS AND BEGINS TO WASH OUT OVER THE SOUTHERN PENINSULA. WILL KEEP LOW POPS FOR LIGHT SHOWERS/DRIZZLE FOR THE FIRST HALF OF THE OVERNIGHT...MAINLY TO THE SOUTH OF THE TAMPA BAY REGION AND THEN LOOKS AS THROUGH MOST OF THE ACTIVITY SHOULD FADE. THERE IS GOING TO BE QUITE A BIT OF LOW LEVEL MOISTURE STILL IN PLACE OVERNIGHT...AND THE SREF AND STATISTICAL GUIDANCE ARE SHOWING A LOT OF LOWER CLOUDS DEVELOPING. SO EVEN PLACE THAT DO NOT CLOUD OVER DURING THE DAY FROM THE FRONT ITSELF...SHOULD BEGIN TO BECOME OVERCAST OVERNIGHT. THESE CLOUDS WILL LIKELY BE WITH US FOR A GOOD PORTION OF THE DAY ON WEDNESDAY (ESPECIALLY THE FIRST HALF)...AND HENCE WILL NOT HAVE ALL THAT MUCH SUN IN THE FORECAST FOR WEDNESDAY. THE GUIDANCE MEMBERS ARE INDICATING THE DEVELOPMENT OF AN INVERTED TROUGH OVER THE GULF STREAM OFF THE FL EAST COAST DURING LATER TONIGHT AND EARLY WEDNESDAY THAT THEN MIGRATES WESTWARD A BIT DURING THE DAY. THIS FOCUS ALONG WITH SOME SPEED CONVERGENCE ALONG THE COAST LOOKS TO BE ENOUGH FOR SHOWERS TO BEGIN MIGRATING ONSHORE. NOT IMPOSSIBLE THAT A FEW OF THESE SHOWERS OR SPRINKLES COULD SURVIVE THE TREK ACROSS THE PENINSULA TO REACH SOME OF OUR EASTERN AND SOUTHERN ZONES. GOING TO KEEP THE POPS AT OR BELOW 20% FOR NOW...AND WILL MENTION A FEW SPRINKLES IN THE FORECAST WEDNESDAY FOR THE SOUTHERN HALF OF THE FORECAST AREA. THOSE SPRINKLES SHOULD BE GONE BY TOMORROW EVENING...AND AS IT LOOKS NOW...ALTHOUGH A LOT OF CLOUDS AROUND...THE WEATHER FOR AFTER DARK ON NEW YEARS EVE LOOKS DRY WITH SEASONABLE TEMPERATURES. && .LONG TERM (THURSDAY THROUGH NEXT TUESDAY)... ZONAL FLOW ALOFT AND WEAK RIDGING WILL BE IN PLACE TO START THE PERIOD WITH A REMNANT BOUNDARY DRAPED ACROSS SOUTH FL. THE BOUNDARY WILL LIFT NORTH OVER THE AREA INTO FRIDAY AS A TROUGH DEVELOPS OVER THE GULF STREAM JUST OFF THE FL EAST COAST AND A WEAK LOW DEEPENS OFF OF THE TEXAS COAST IN THE GULF OF MEXICO. THIS WILL ALLOW FOR A SLIGHT CHANCE OF RAIN WEDNESDAY NIGHT AND THURSDAY. FLOW ALOFT WILL BECOME SW FOR THE WEEKEND AS WEAK RIDGING BUILDS OVER THE STATE FROM THE ATLANTIC AND THE LOW OFF OF TEXAS LIFTS NE AND DRAGS A COLD FRONT INTO THE REGION BY SUNDAY. THE FRONT WILL SETTLE INTO THE AREA SUNDAY AFTERNOON AND THEN STALL ACROSS THE NORTHERN HALF OF THE PENINSULA FOR EARLY NEXT WEEK. THIS WILL ALLOW FOR A FEW SHOWERS MAINLY ACROSS THE NATURE COAST SATURDAY THROUGH SUNDAY...AND INLAND ACROSS THE AREA MONDAY. TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH THE WEEKEND AND FALL A COUPLE OF DEGREES TO CLOSER TO NORMAL FOR EARLY NEXT WEEK. && .AVIATION... MVFR TO OCCASIONAL IFR CONDITIONS THIS AFTERNOON FROM KSRQ/KPIE/KTPA AND KLAL. SOUTH OF THE FRONTAL BAND FROM KPGD TO KRSW WILL CONTINUE TO SEE PREVAILING VFR CONDITIONS INTO THE EVENING HOURS. GOOD AGREEMENT AMONG THE DETERMINISTIC AND STATISTICAL GUIDANCE THAT WE WILL SEE AN EXPANSION OF THE LOWER CLOUDS DURING THE SECOND HALF OF THE NIGHT INTO WEDNESDAY MORNING. SO ALTHOUGH EVEN THE NORTHERN TERMINALS MAY SEE A BRIEF WINDOW OF IMPROVEMENT THIS EVENING...GOING WITH PREVAILING MVFR CIGS FOR ALL TERMINALS AFTER 06Z. IF THE MAV IS CORRECT THAN PERIODS OF IFR CIGS ARE POSSIBLE. BEST CHANCES TO SEE ANY FOG/VIS RESTRICTIONS WILL BE DOWN TOWARD KPGD AND KRSW. EXPECT MVFR CATEGORY CIGS TO HOLD THROUGH MUCH OF THE MORNING AT MANY SPOTS...IF NOT UNTIL THE END OF THE TAF PERIOD. && .MARINE... MARINE FORECAST AREA REMAINS DIVIDED WITH IMPACTS ASSOCIATED WITH A QUASI-STATIONARY FRONTAL SYSTEM DRAPED OVER THE WATERS FROM OFF HERNANDO BEACH SOUTHWARD TO OFF THE COAST FROM VENICE. MAIN AREA OF SHOWERS EXTENDS OFF THE COAST OF HOLIDAY AND OUT 100 NM INTO THE EASTERN GULF OF MEXICO. CONDITIONS EARLY THIS AFTERNOON /2PM/ REPORTS SEAS AROUND 6 FEET WITH A PERIOD OF 5 SECONDS AT BUOY036 112 MILES W-NW OF TAMPA WHILE BUOY03 REPORTS SEAS OF 2 FEET AND A PERIOD OF 8 SECONDS IN THE CALMER AIRMASS 208 MILES WEST OF NAPLES. NO FLAGS EXPECTED THROUGH THE PERIOD AND SHOWER ACTIVITY WILL GRADUALLY DIMINISH TONIGHT. && .FIRE WEATHER... NO SIGNIFICANT FIRE WEATHER CONCERNS EXPECTED THE NEXT SEVERAL DAYS. WEAK COLD FRONT WILL EXIT SOUTH OF THE AREA THIS EVENING ALLOWING SOMEWHAT DRIER AIR TO ARRIVE FROM THE NORTH FOR WEDNESDAY AND THURSDAY. THEREAFTER...INCREASING TEMPERATURES AND LOW LEVEL MOISTURE IS EXPECTED FOR THE END OF THE WEEK. FOG POTENTIAL... PATCHY FOG IS EXPECTED TO DEVELOP OVERNIGHT...MAINLY TO THE SOUTH OF THE I-4 CORRIDOR WITH THE BEST CHANCES FOR ANY SIGNIFICANT FOG OCCURRING FROM AROUND PUNTA GORDA AND SOUTHWARD. && .PRELIMINARY POINT TEMPS/POPS... TPA 61 75 60 76 / 40 10 10 10 FMY 65 79 64 80 / 30 20 10 20 GIF 61 76 58 76 / 40 10 10 10 SRQ 63 77 61 77 / 40 10 10 10 BKV 58 74 54 74 / 20 10 20 10 SPG 63 75 61 74 / 40 10 10 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ SYNOPSIS/SHORT TERM/AVIATION/FIRE WX...MROCZKA LONG TERM...HUBBARD MARINE...LAMARRE
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1020 AM EST TUE DEC 30 2014 .DISCUSSION... FRONTAL BNDRY JUST N OF THE I-4 CORRIDOR HAS STALLED DUE TO A STUBBORN H100-H70 HI PRES RIDGE OVER THE FL STRAITS. MRNG RAOBS SHOW DEEP MOISTURE AHEAD OF THE FRONT WITH PWAT VALUES BTWN 1.5"-1.8" AS KXMR-KTBW RESPECTABLY...BUT DECREASING EITHER SIDE OF THE BNDRY TO 1.2" AT KJAX/KMFL. RUC ANALYSIS SHOWS RESPECTABLE MID/UPR LVL DYNAMIC SUPPORT ALONG THE FRNTL BNDRY OVER THE GOMEX...BUT LITTLE OVER CENTRAL FL. LATEST RADAR TREND REFLECTS THIS LACK OF SUPPORT AS AN AREA OF MODERATE RAIN THAT MOVED ONSHORE OVER TAMPA BAY HAS WEAKENED INTO A BROAD AREA OF LIGHT STRATIFORM RAIN AS IT APPROACHED THE FL TURNPIKE. WHILE THE FRONT HAS STALLED...RUC SHOWS AN H100-H70 N/NW SURGE OVER THE LWR MS VALLEY THAT SHOULD GIVE IT THE PUSH IT NEEDS TO PLOW THE RIDGE AXIS OUT OF THE FL STRAITS LATER TODAY. LITTLE IN THE WAY OF SFC HEATING N OF SR60 AS CLOUD COVER ENTRENCHED WITHIN THE FRONTAL TROF STREAMS ACRS CENTRAL FL. PRECIP WILL BE SPOTTY AT BEST WITH QPF VALUES AOB 0.10". FURTHER S...WHILE SUNNY SKIES AND SFC DEWPOINTS IN THE M/U60S NORMALLY WOULD SUGGEST THE THREAT OF TSRAS...THE LACK OF ANY SIG DYNAMIC SUPPORT COUPLED WITH A LINGERING SUBSIDENCE INVERSION IN THE H85-H70 LYR (LAPSE RATES BTWN 3.0-4.0C/KM) SUGGESTS THE SRN CWA WILL REMAIN DRY. WILL KNOCK A FEW DEG OF MAX TEMPS FROM BREVARD/OSCEOLA NWD...ALSO WILL SHAVE POPS BACK A TOUCH ARND LAKE OKEECHOBEE. && .AVIATION...THRU 31/12Z SFC WNDS: THRU 30/20Z...W/SW 5-8KTS BCMG N. AFT 30/20Z...N 4-7KTS. VSBYS/WX: THRU 30/20Z...N OF KTIX-KISM...PDS OF MVFR IN -RA/BR...S OF KTIX-KISM PREVAILING VFR WITH LCL IFR IN BR/FG ENDING BY 30/16Z. BTWN 30/20Z-31/04Z...N OF KTIX-KISM VFR...S OF KTIX-KISM PDS OF MVFR IN -RA/BR. AFT 31/04Z...AREAS MVFR BR WITH LCL LIFR FG N OF KDAB-KISM. CIGS: THRU 30/17Z...N OF KTIX-KISM PREVAILING BTWN FL015-020 WITH AREAS LIFR BLO FL005...S OF KTIX-KISM PREVAILING AOA FL120 WITH LCL LIFR BLO FL004. BTWN 30/17Z-31/04Z...PREVAILING FL040-060 WITH AREAS MVFR FL020-030. AFT 31/04Z...PREVAILING MVFR FL020-030...N OF KTIX-KISM AREAS LIFR BLO FL005...S OF KTIX-KISM LCL IFR BTWN FL005-009. && .MARINE... RUC ANALYSIS SHOWS TEH FRONTAL TROF EXTENDING FROM THE CENTRAL GOMEX TO THE NC OUTER BANKS. LATEST SFC OBS INDICATE THE FRONT HAS PUSHED S OF ST. AUGUSTINE BUT REMAINS N OF BUOY009...FOG/CALM WINDS ALONG THE COAST BTWN PALM COAST AND NEW SMYRNA BEACH AS OF 14Z SUGGEST THE BNDRY IS IN THE VCNTY OF THE VOLUSIA/FLAGLER COUNTY LINE. DESPITE A STUBBORN RIDGE AXIS OVER THE FL STRAITS...THE FRONT WILL PUSH THRU CENTRAL FL THRU SUNSET...FORCING SFC/BNDRY LYR WINDS TO VEER FROM W/SW TO DUE NORTH...GENERALLY BTWN 10-15KTS. SEAS AOB 2FT NEARSHORE AND 2-3FT OFFSHORE...INCREASING TO 2-3FT NEARSHORE AND 3-4FT OFFSHORE AS WINDS SWING ARND TO THE N. NO SIG CHANGES. && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...BRAGAW LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1010 AM EST TUE DEC 30 2014 .UPDATE (REST OF TODAY THROUGH WEDNESDAY)... 15Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW MUCH OF THE NATION UNDER A BROAD LONGWAVE TROUGH. THE MOST ENERGETIC FEATURE WITHIN THIS TROUGH IS A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE INTERMOUNTAIN WEST WHICH IS PROGGED BY ALL THE NUMERICAL GUIDANCE TO BECOME A LARGE CUTOFF LOW OVER THE SOUTHWESTERN STATES BEFORE EJECTING EASTWARD ACROSS THE SOUTHERN/CENTRAL PLAINS LATER IN THE WEEK. OUR FORECAST AREA RESIDES WITHIN A ZONE OF DEEP LAYER SOUTHWEST FLOW BETWEEN THE LONGWAVE TROUGH AND AND WEST-EAST ORIENTED RIDGE ACROSS THE NORTHWEST CARIBBEAN. A PLUME OF SOUTHERN STREAM MOISTURE IS STILL IN WV IMAGERY RIDGING THIS FLOW OVER THE EASTERN GULF OF MEXICO AND FL PENINSULA. AT THE SURFACE...A WEAK COLD FRONT HAS ENTERED THE NORTHERN FLORIDA PENINSULA AND IS NOW STRETCHED ACROSS THE NATURE COAST ON A SLOW TREK SOUTHWARD THROUGH THE DAY. REGIONAL RADARS CONTINUE TO SHOW AN EXPANSION OF THE SHOWERS ALONG AND AHEAD OF THIS BOUNDARY...AND THIS IS LIKELY RELATED TO SOME ADDED SYNOPTIC SUPPORT FOR LIFT ASSOCIATED WITH A WEAK/SUBTLE PASSING SHORTWAVE ALOFT OVER THE NE GULF OF MEXICO. HAVE SUBSTANTIALLY INCREASED RAIN CHANCES FOR THE MORNING THROUGH WEST-CENTRAL FLORIDA AS A SOGGY NEXT FEW HOURS NOW APPEARS LIKELY. FORECAST GRIDS AND TEXT PRODUCTS HAVE BEEN UPDATED. THE RAIN IS ALSO HELPING LIFT SOME OF THE DENSE FOG SEEN AROUND THE AREA. FOR LOCATIONS SOUTH OF THE RAIN SHIELD...THE DENSE FOG IS HOLDING IN LONGER. JUST BEGINNING TO SEE THE EROSION OF THIS FOG DUE TO DIURNAL MIXING AND VISIBILITIES SHOULD BE IMPROVING QUICKLY INTO THE LATER MORNING HOURS. WITH ALL THIS IN MIND WILL ALLOW THE DENSE FOG ADVISORY TO EXPIRE AT 10AM...EVEN THOUGH A FEW SPOTS MAY STILL TECHNICALLY MEET CRITERIA FOR A BIT LONGER. USING THE LATEST HRRR FOR TIMING...THE FRONT STILL LOOKS TO ARRIVE AT THE I-4 CORRIDOR AROUND MIDDAY/EARLY AFTERNOON AND THEN SLOWLY SETTLE SOUTH TO NEAR PUNTA GORDA AROUND SUNSET. THE ORGANIZATION AND COVERAGE OF SHOWERS SHOULD BEGIN TO DIMINISH DURING THE SECOND HALF OF THE DAY AS THE SHORTWAVE INFLUENCE PASSES TO OUR EAST. HOWEVER...THE LOW LEVEL BOUNDARY FOCUS WILL STILL KEEP THE CHANCE FOR MORE SCT SHOWERS IN THE FORECAST. ALSO WITH THE FLOW BECOMING MORE AND MORE PARALLEL TO THE FRONT...THE ACTUALLY BOUNDARY PASSAGE WILL NOT NECESSARILY END THE CHANCE FOR RAIN AS MANY OF THE GUIDANCE MEMBERS ARE INDICATING THE BOUNDARY WILL TAKE ON AN INCREASINGLY ANAFRONT CONFIGURATION BY LATER TODAY WHERE BETTER CHANCES FOR THE CLOUDS AND SHOWERS ARE ACTUALLY ALONG AND BEHIND THE BOUNDARY. FOR OUR SOUTHERN ZONES...FOG WILL BE LIFTING BY MIDDAY. YOUR SHOWERS CHANCES WILL BE INCREASING LATER THIS AFTERNOON AND INTO THE EVENING AS THE BOUNDARY MAKES IT WAYS SOUTHWARD. TONIGHT AND WEDNESDAY...THE FRONT STALLS AND BEGINS TO WASH OUT OVER THE SOUTHERN PENINSULA. THE GUIDANCE MEMBERS ARE ALL STARTING TO INDICATE THE DEVELOPMENT OF AN INVERTED TROUGH OVER THE GULF STREAM OFF THE FL EAST COAST DURING THIS TIME. THIS FOCUS ALONG WITH SOME SPEED CONVERGENCE ALONG THE COAST LOOKS TO BE ENOUGH FOR SHOWERS TO BEGIN MIGRATING ONSHORE. GOING TO HAVE TO LOOK AT THIS A BIT CLOSER WITH THE 12Z GUIDANCE AS SOME OF THESE SHOWERS MAY HAVE A CHANCE TO MIGRATE INLAND ENOUGH TO IMPACT PORTIONS OF POLK/HIGHLANDS COUNTIES ON WEDNESDAY. WOULD NOT BE A LOT OF RAIN...BUT WOULD NOT BE THE COMPLETELY DRY FORECAST CURRENTLY IN THE GRIDS. ELSEWHERE WEDNESDAY STILL LOOKS TO BE MAINLY DRY...HOWEVER PROB NOT A WHOLE LOT OF SUN AROUND...ESPECIALLY FOR THE I-4 CORRIDOR AND SOUTHWARD. && .AVIATION... VARYING CONDITIONS OUT THERE THIS MORNING WITH A MIX OF FOG AND RAIN. ALTHOUGH MANY STATIONS WILL NOT BE PREVAILING LIFR OR LOWER...PERIODS OF THESE LOW RESTRICTIONS WILL REMAIN POSSIBLE FOR ALL TERMINALS THROUGH THE MORNING HOURS. IMPROVEMENT WILL OCCUR FOR THE SECOND HALF OF THE DAY...HOWEVER AT LEAST PERIODS OF MVFR CONDITIONS SHOULD STILL BE EXPECTED. && .MARINE... AREAS OF SEA FOG REMAIN OVER THE WATERS THIS MORNING AHEAD OF AN APPROACHING COLD FRONT. THE FOG HAS BECOME LESS PREVALENT OVER THE PAST COUPLE OF HOURS...ESPECIALLY OVER TAMPA BAY AND THE GULF WATERS TO THE WEST OF THE BAY AS SHOWERS HAVE BEEN ONGOING THERE FOR SEVERAL HOURS. THE SEA FOG IS EXPECTED TO DISSIPATE BY LATE MORNING OR EARLY AFTERNOON AS THE FRONT SINKS SOUTHWARD. THERE WILL BE A CHANCE FOR SHOWERS THROUGH THE REST OF THE DAY AS WELL...WHICH COULD BRIEFLY REDUCE VISIBILITY OVER THE WATERS. && .PRELIMINARY POINT TEMPS/POPS... TPA 78 63 75 59 / 90 10 20 10 FMY 82 65 81 63 / 30 20 20 10 GIF 79 62 75 57 / 80 10 20 10 SRQ 79 63 76 60 / 70 10 20 10 BKV 78 59 74 53 / 60 10 10 10 SPG 77 65 74 60 / 90 10 20 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/AVIATION...MROCZKA MARINE...CARLISLE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
825 AM EST TUE DEC 30 2014 .UPDATE (REST OF TODAY THROUGH WEDNESDAY)... 13Z WATER VAPOR AND H4 RAP ANALYSIS CONTINUE TO SHOW MUCH OF THE NATION UNDER A BROAD LONGWAVE TROUGH. THE MOST ENERGETIC FEATURE WITHIN THIS TROUGH IS A STRONG SHORTWAVE DROPPING SOUTH THROUGH THE INTERMOUNTAIN WEST WHICH IS PROGGED BY ALL THE NUMERICAL GUIDANCE TO BECOME A LARGE CUTOFF LOW OVER THE SOUTHWESTERN STATES BEFORE EJECTING EASTWARD ACROSS THE SOUTHERN/CENTRAL PLAINS LATER IN THE WEEK. OUR FORECAST AREA RESIDES WITHIN A ZONE OF DEEP LAYER SOUTHWEST FLOW BETWEEN THE LONGWAVE TROUGH AND AND WEST-EAST ORIENTED RIDGE ACROSS THE NORTHWEST CARIBBEAN. A PLUME OF SOUTHERN STREAM MOISTURE IS STILL IN WV IMAGERY RIDGING THIS FLOW OVER THE EASTERN GULF OF MEXICO AND FL PENINSULA. AT THE SURFACE...A WEAK COLD FRONT HAS ENTERED THE NORTHERN FLORIDA PENINSULA AND IS NOW STRETCHED ACROSS THE NATURE COAST ON A SLOW TREK SOUTHWARD THROUGH THE DAY. REGIONAL RADARS HAVE SHOWN A RAPID EXPANSION OF THE SHOWERS ALONG AND AHEAD OF THIS BOUNDARY DURING THE PAST FEW HOURS...AND THIS IS LIKELY RELATED TO SOME ADDED SYNOPTIC SUPPORT FOR LIFT ASSOCIATED WITH A WEAK/SUBTLE PASSING SHORTWAVE ALOFT OVER THE NE GULF OF MEXICO. HAVE SUBSTANTIALLY INCREASED RAIN CHANCES FOR THE MORNING THROUGH WEST-CENTRAL FLORIDA AS A SOGGY NEXT FEW HOURS NOW APPEARS LIKELY. FORECAST GRIDS AND TEXT PRODUCTS HAVE BEEN UPDATED. THE RAIN IS ALSO HELPING LIFT SOME OF THE DENSE FOG SEEN AROUND THE AREA AND WILL BE MAKING DECISIONS ON WHAT TO DO WITH THE DENSE FOG ADVISORY IN THE NEXT COUPLE OF HOURS. USING THE LATEST HRRR FOR TIMING...THE FRONT LOOKS TO ARRIVE THE I-4 CORRIDOR AROUND MIDDAY AND THEN SLOWLY SETTLE SOUTH TO NEAR PUNTA GORDA AROUND SUNSET. THE ORGANIZATION AND COVERAGE OF SHOWERS SHOULD BEGIN TO DIMINISH DURING THE SECOND HALF OF THE DAY AS THE SHORTWAVE INFLUENCE PASSES TO OUR EAST. HOWEVER...THE LOW LEVEL BOUNDARY FOCUS WILL STILL KEEP THE CHANCE FOR MORE SCT SHOWERS IN THE FORECAST. ALSO WITH THE FLOW BECOMING MORE AND MORE PARALLEL TO THE FRONT...THE ACTUALLY BOUNDARY PASSAGE WILL NOT NECESSARILY END THE CHANCE FOR RAIN AS MANY OF THE GUIDANCE MEMBERS ARE INDICATING THE BOUNDARY WILL TAKE ON AN INCREASINGLY ANAFRONT CONFIGURATION BY LATER TODAY WHERE BETTER CHANCES FOR THE CLOUDS AND SHOWERS ARE ACTUALLY ALONG AND BEHIND THE BOUNDARY. FOR OUR SOUTHERN ZONES...A COUPLE MORE HOURS WITH THE FOG AND THEN WE SHOULD BEGIN TO BURN IT OFF. YOUR SHOWERS CHANCES WILL BE INCREASING THIS AFTERNOON AND INTO THE EVENING AS THE BOUNDARY MAKES IT WAYS SOUTHWARD. TONIGHT AND WEDNESDAY...THE FRONT STALLS AND BEGINS TO WASH OUT OVER THE SOUTHERN PENINSULA. THE GUIDANCE MEMBERS ARE ALL STARTING TO INDICATE THE DEVELOPMENT OF AN INVERTED TROUGH OVER THE GULF STREAM OFF THE FL EAST COAST DURING THIS TIME. THIS FOCUS ALONG WITH SOME SPEED CONVERGENCE ALONG THE COAST LOOKS TO BE ENOUGH FOR SHOWERS TO BEGIN MIGRATING ONSHORE. GOING TO HAVE TO LOOK AT THIS A BIT CLOSER WITH THE 12Z GUIDANCE AS SOME OF THESE SHOWERS MAY HAVE A CHANCE TO MIGRATE INLAND ENOUGH TO IMPACT PORTIONS OF POLK/HIGHLANDS COUNTIES ON WEDNESDAY. WOULD NOT BE A LOT OF RAIN...BUT WOULD NOT BE THE COMPLETELY DRY FORECAST CURRENTLY IN THE GRIDS. ELSEWHERE WEDNESDAY STILL LOOKS TO BE MAINLY DRY...HOWEVER PROB NOT A WHOLE LOT OF SUN AROUND...ESPECIALLY FOR THE I-4 CORRIDOR AND SOUTHWARD. && .AVIATION... VARYING CONDITIONS OUT THERE THIS MORNING WITH A MIX OF FOG AND RAIN. ALTHOUGH MANY STATIONS WILL NOT BE PREVAILING LIFR OR LOWER...PERIODS OF THESE LOW RESTRICTIONS WILL REMAIN POSSIBLE FOR ALL TERMINALS THROUGH THE MORNING HOURS. IMPROVEMENT WILL OCCUR FOR THE SECOND HALF OF THE DAY...HOWEVER AT LEAST PERIODS OF MVFR CONDITIONS SHOULD STILL BE EXPECTED. && .MARINE... DENSE SEA FOG WILL BE LOCATED OVER THE NEAR SHORE COASTAL WATERS SOUTH OF THE COLD FRONT. AS THE COLD FRONT GRADUALLY SINKS SOUTH TODAY...THE AREA OF SEA FOG WILL BE SINK SOUTH AND DECREASE IN AREAL COVERAGE...DISSIPATING BY LATE TODAY. WEAK HIGH PRESSURE WILL BUILD OVER THE WATERS BEHIND THE FRONT THROUGH THE REMAINDER OF THE WEEK. WINDS WILL BE LESS THAN 15 KNOTS WITH SEAS LESS THAN 4 FEET THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... TPA 78 63 75 59 / 90 10 20 10 FMY 82 65 81 63 / 30 20 20 10 GIF 79 62 75 57 / 80 10 20 10 SRQ 79 63 76 60 / 70 10 20 10 BKV 78 59 74 53 / 60 10 10 10 SPG 77 65 74 60 / 90 10 20 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR COASTAL CHARLOTTE-COASTAL CITRUS-COASTAL HERNANDO- COASTAL HILLSBOROUGH-COASTAL LEE-COASTAL LEVY-COASTAL MANATEE-COASTAL PASCO-COASTAL SARASOTA-DESOTO-HARDEE- HIGHLANDS-INLAND CHARLOTTE-INLAND HERNANDO-INLAND HILLSBOROUGH-INLAND LEE-INLAND MANATEE-INLAND PASCO- INLAND SARASOTA-PINELLAS-POLK. GULF WATERS...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM-CHARLOTTE HARBOR AND PINE ISLAND SOUND-ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-TAMPA BAY WATERS-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 NM. && $$ UPDATE/AVIATION...MROCZKA MARINE...CARLISLE
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
614 AM EST TUE DEC 30 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE AREA TODAY INTO FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL TROUGH WILL DEVELOP SATURDAY AND LIFT NORTH OF THE REGION BY SUNDAY. A COLD FRONT WILL THEN PASS OFF THE COAST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MESOSCALE UPDATE...THE DENSE FOG IN THE SAVANNAH AND BEAUFORT AREAS HAS LIFTED BACK INTO A VERY LOW STRATUS DECK. WEBCAMS AND SURFACE OBSERVATIONS INDICATE VSBYS HAVE IMPROVED TO 1-2 MILES. HOWEVER...LOCALLY DENSE FOG IS STILL LIKELY NEAR BODIES OF WATER AND OTHER LOW LYING AREAS. AN AREA OF DENSE FOG IS TRYING TO NOSE INTO PARTS OF JENKINS-CANDLER-EVANS-TATTNALL AND BULLOCH. WITH SUNRISE APPROACHING...PREFER TO HANDLE THIS WITH A SPECIAL WEATHER STATEMENT. HOWEVER...A DENSE FOG ADV CAN NOT BE RULED OUT. SURFACE TROUGH/SECONDARY COLD SURGE IS WORKING ITS WAY SOUTH OF THE SOUTH SANTEE RIVER AND WILL CROSS THE I-26 CORRIDOR THROUGH SUNRISE. HIGHS WILL LIKELY OCCUR DAY TIME HIGHS WILL LIKELY OCCUR IN THE 7-9AM TIME FRAME BEFORE TEMPERATURES HOLD STEADY THEN POSSIBLY FALL. ADJUSTED HOURLY TEMPERATURES ACROSS THE CHARLESTON TRI- COUNTY AREA A BIT. TODAY...LOW CONFIDENCE FORECAST TODAY. THE COLD FRONT AND ASSOCIATED FRONTAL WAVE ARE NOW WELL OFFSHORE WITH A NORTHERLY LOW-LEVEL FLOW DOMINATING IN ITS WAKE. A WEAK POST FRONTAL SURFACE TROUGH DELINEATING A SURGE OF COOLER AIR WILL APPROACH THE CHARLESTON AREA BY SUNRISE...THE SAVANNAH AREA BY MID/LATE MORNING AND FINALLY CLEARING THE ALTAMAHA RIVER BY LATE AFTERNOON. MODELS SHOW A TRANSIENT HYBRID WEDGE SETTING UP ACROSS MAINLY THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA IN THE WAKE OF THE TROUGH AS 290K ISENTROPIC ASSENT BRIEFLY INTENSIFIES ATOP THE LOW- LEVEL POST FRONTAL WEDGING PATTERN. THIS PATTERN WILL ESSENTIALLY REINFORCE THE WIDESPREAD LOW CLOUDS AND PATCHY DRIZZLE THAT ARE ALREADY IN PLACE ACROSS THE LOWCOUNTRY AND COASTAL EMPIRE FOR A GOOD PORTION OF THE DAY. THE TEMPERATURE FORECAST IS PROVING TO BE EXTREMELY CHALLENGING AS A RESULT AND ASSUMES THE TRANSIENT WEDGE ACTUALLY DEVELOPS AS DEPICTED IN THE HIGHER RESOLUTION DATA SETS. DAILY HIGHS /7AM-6PM/ WILL LIKELY OCCUR BY MID-MORNING ACROSS THE CHARLESTON TRI-COUNTY AREA AND EARLY AFTERNOON ACROSS THE REMAINDER OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. TEMPERATURES WILL LIKELY HOLD STEADY OR SLOWLY FALL NORTH THE SAVANNAH RIVER AS THE WEDGE BRIEFING INTENSIFIES. HIGHS WILL RANGE MID 50S NORTH...UPPER 50/NEAR 60 CENTRAL TO THE LOWER-MID 60S SOUTH. UTILIZE A 30/30/30 BLEND OF RAP/H3R AND GLAMP DATA TO CONSTRUCT HOURLY TEMPERATURES. SINCE THIS IS A VERY LOW CONFIDENCE FORECAST...CHANGES--SOME POSSIBLY SIGNIFICANT--WILL LIKELY BE NEEDED THROUGHOUT THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... TONIGHT...THE TRANSIENT HYBRID WEDGE WILL QUICKLY BREAKDOWN THIS EVENING AS HIGH PRESSURE FINALLY BRIDGES THE SOUTHERN APPALACHIANS AND BECOMES MORE DOMINATE ACROSS THE SOUTHEAST STATES. A GOOD BIT OF CLOUD COVER WILL LINGER THROUGH THE NIGHT WITH THE POTENTIAL FOR SOME CLEARING TO OCCUR ACROSS THE NORTH AFTER 3 AM. WILL HAVE TO WATCH FOR SOME FOG TO DEVELOP AFTER MIDNIGHT...BUT THIS DOES NOT LOOK SIGNIFICANT AT THIS TIME. LOWS WILL RANGE FROM THE MID- UPPER 30S INTERIOR NORTH WHERE THE BETTER CHANCES FOR CLEARING WILL OCCUR WITH UPPER 30S TO LOWER 40S ELSEWHERE...EXCEPT MID 40S ALONG THE GEORGIA COAST WHERE ONSHORE WINDS WILL MODERATE TEMPERATURES A BIT. WEDNESDAY AND THURSDAY...EXPANSIVE SURFACE HIGH PRESSURE WILL BE GRADUALLY WEAKENING AS IT SLIPS TOWARD THE EAST COAST UNDER RELATIVELY ZONAL FLOW ALOFT. EXPECT DRY CONDITIONS TO PREVAIL WEDNESDAY AND THURSDAY WITHIN THIS PATTERN. TEMPERATURES WEDNESDAY WILL BE A FEW DEGREES COOLER THAN NORMAL...PEAKING IN THE MID TO UPPER 50S DURING THE AFTERNOON AND FALLING INTO THE LOW 30S NORTH TO UPPER 30S COAST AND SOUTH OVERNIGHT. NORTH FLOW WEAKENS ON THURSDAY AS THE CENTER OF THE SURFACE HIGH PASSES DIRECTLY OVER THE REGION...AND WITH SUBTLE RIDGING BUILDING UP FROM THE BAHAMAS...HIGH TEMPERATURES WILL MODERATE TOWARD SEASONAL NORMALS IN THE UPPER 50S TO LOWER 60S. A GRADUALLY IMPROVING TAP INTO GULF MOISTURE LATE THURSDAY WILL SUPPORT INCREASING CLOUDS...WITH LOW TEMPERATURES A FEW DEGREES MILDER IN THE UPPER 30S INLAND TO LOW 40S CLOSER TO THE COAST. FRIDAY...AN UPPER LEVEL CUT OFF LOW WILL MOVE FROM THE SOUTHWEST STATES INTO THE SOUTHERN PLAINS...PROVIDING THE ENERGY TO DEVELOP A WAVE OF LOW PRESSURE ACROSS THE WESTERN GULF LATE IN THE DAY. THE SOUTHEAST STATES WILL REMAIN ON THE PERIPHERY OF ATLANTIC HIGH PRESSURE...WHERE SHORTWAVE ENERGY TRACKING UP FROM THE GULF OF MEXICO WILL SUPPORT THE GRADUAL AMPLIFICATION OF A COASTAL TROUGH. NUMERICAL MODEL SOLUTIONS ARE INDICATING SUFFICIENT ISENTROPIC ASCENT BETWEEN THE COASTAL TROUGH AND A DEVELOPING INLAND WEDGE TO GENERATE ISOLATED TO SCATTERED RAIN...WITH BEST COVERAGE ACROSS NORTHERN AND INLAND AREAS. TEMPERATURES COULD BE A DEGREE OR TWO COOLER THAN THE PREVIOUS DAY GIVEN THE INCREASING CLOUD COVER...YET STILL RANGE NEAR SEASONAL NORMALS IN THE UPPER 50S TO LOW 60S. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... FRIDAY NIGHT THROUGH SUNDAY...A TRANSIENT INLAND WEDGE/COASTAL TROUGH PATTERN WILL BE IN PLACE THROUGH EARLY SATURDAY...BEFORE THE COASTAL TROUGH QUICKLY LIFTS NORTH OF THE REGION AHEAD OF AN APPROACHING COLD FRONT FROM THE WEST. THE CUT OFF LOW ACROSS THE SOUTHERN PLAINS WILL DAMPEN AND LIFT NORTHEAST INTO THE OHIO VALLEY ON SATURDAY. THE ASSOCIATED SURFACE LOW WILL PULL INTO THE NEW ENGLAND STATES SUNDAY...WITH ITS TRAILING COLD FRONT PROGRESSING THROUGH THE MID ATLANTIC AND SOUTHEAST STATES BY SUNDAY AFTERNOON. HIGH TEMPERATURES WILL SURGE INTO THE 60S TO AROUND 70 DEGREES SATURDAY AND SUNDAY WITHIN WARM SOUTHERLY FLOW AHEAD OF THE FRONT...WHILE SCATTERED SHOWERS ARE POSSIBLE SATURDAY THROUGH SUNDAY AFTERNOON. PREFER TO REMAIN RATHER CONSERVATIVE WITH RAIN CHANCES AT THIS POINT...CONSIDERING THE SOUTHERN END OF THE FRONT WILL RUN INTO THE PERIPHERY OF THE SUBTROPICAL RIDGE AND BECOME PARALLEL TO FLOW ALOFT. SUNDAY NIGHT THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BUILD IN THE WAKE OF THE DEPARTING COLD FRONT EARLY NEXT WEEK...EVENTUALLY SETTLING TO THE NORTH OF THE AREA. RAIN FREE CONDITIONS WILL PREVAIL. TEMPERATURES ARE EXPECTED TO RETURN TO SEASONAL NORMALS...POSSIBLY COOLER IF A WEDGE PATTERN CAN SET UP TOWARD THE END OF THE FORECAST PERIOD. && .AVIATION /11Z TUESDAY THROUGH SATURDAY/... CIGS WILL REMAIN BELOW ALTERNATE MINIMUMS THROUGH 14-15Z WITH CIGS RISING THEREAFTER. EXPECT MVFR CIGS TO RETURN TO KSAV BY 16Z WHICH WILL REMAIN IN PLACE THROUGH THE REMAINDER OF THE 12Z TAF PERIOD. AT KCHS...CIGS WILL BE SLOWER TO RISE WITH IFR CIGS RETURNING BY 17-18Z. THESE CONDITIONS WILL LINGER THROUGH 12Z WEDNESDAY. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL WEDNESDAY AND THURSDAY. CHANCES FOR FLIGHT RESTRICTIONS INCREASE INTO THE WEEKEND AS THE NEXT SYSTEM IMPACTS THE REGION. && .MARINE... TODAY...CEILINGS OF 100 FT AT THE HILTON HEAD AIRPORT AND WEBCAMS IN THE SAVANNAH RIVER AS WELL AS TYBEE ISLAND SUGGEST SEA FOG IS IN PLACE ACROSS THE COASTAL WATERS THIS MORNING. IT IS UNCLEAR EXACTLY HOW WIDESPREAD THE FOG IS...BUT RAP VISIBILITIES DATA SUGGEST ITS PROBABLY PRETTY WIDESPREAD. WFO JAX RECENTLY RELAYED THAT THE BAR PILOTS OUT OF SAINT SIMMONS ARE REPORTING IMPROVED VSBYS OVER THE PAST HOUR...BUT THE SHELF WATERS OFF TYBEE ISLAND ARE SEVERAL DEGREES COOLER. PREFER TO HOLD THE MARINE DENSE FOG ADVISORY FOR THE GEORGIA NEARSHORE AND BEAUFORT COUNTY WATERS UNTIL 8 AM...OR AT LEAST UNTIL CONDITIONS CAN BE BETTER EVALUATED ON COASTAL WEBCAMS AS THE SUN RISES. OTHERWISE...NORTH WINDS WILL INCREASE TO 10-15 KT TODAY WITH SEAS 1-3 FT. TONIGHT...WINDS WILL INCREASE A BIT AS THE PRESSURE GRADIENT INDUCED BY HIGH PRESSURE BUILDING IN FROM THE WEST TIGHTENS. EXPECT WINDS OF 15-20 KT WITH SEAS 2-3 FT NEARSHORE...4-5 FT OFFSHORE. WEDNESDAY THROUGH SATURDAY...THE PRESSURE GRADIENT WILL REMAIN RELATIVELY TIGHT INTO WEDNESDAY MORNING ON THE PERIPHERY OF HIGH PRESSURE BUILDING FROM THE WEST. MARGINAL SMALL CRAFT ADVISORY WINDS IN GUSTS TO 25 KT COULD LINGER ACROSS THE OFFSHORE GEORGIA WATERS...BEFORE CONDITIONS SLOWLY IMPROVE AS THE DAY PROGRESSES. THE SURFACE HIGH WILL THEN STEADILY TRACK EAST AND ALLOW THE GRADIENT TO RELAX TOWARD THE END OF THE WEEK. A COASTAL TROUGH WILL DEVELOP LATE FRIDAY INTO SATURDAY...WITH INCREASING SOUTHERLY FLOW IN IT WAKE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR AMZ352-354. && $$ ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
409 AM EST TUE DEC 30 2014 .SYNOPSIS... HIGH PRESSURE WILL BUILD INTO THE AREA TODAY INTO FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL TROUGH WILL DEVELOP SATURDAY AND LIFT NORTH OF THE REGION BY SUNDAY. A COLD FRONT WILL THEN PASS OFF THE COAST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THROUGH SUNRISE...STRATUS BUILD DOWN IS IN PROGRESS WITH BKN-OVC CLOUDY LAYERS OF 100-300 FT BEGINNING TO LOWER TO THE SURFACE. ALREADY SEEING A FEW SITES WITH VISIBILITIES LESS THAN 1/2 MILE AND TRENDS ARE BEING WATCHED FOR THE DEVELOPMENT OF DENSE FOG. VSBYS AND WEBCAMS IN THE BEAUFORT AND SAVANNAH AREAS INDICATE THE FOG IS QUICKLY BECOMING DENSE AND WIDESPREAD ENOUGH FOR A DENSE FOG ADVISORY. AN ADVISORY HAS BE ISSUED FOR COASTAL COLLETON-BEAUFORT- INLAND JASPER-COASTAL JASPER-INLAND CHATHAM AND COASTAL CHATHAM UNTIL 9 AM. IT IS UNCLEAR HOW WIDESPREAD THE DENSE FOG WILL BECOME ELSEWHERE...ESPECIALLY GIVEN WINDS ARE AVERAGING 5-10 MPH...BUT THE ADVISORY WILL BE ADJUSTED TEMPORALLY OR SPATIALLY AS NEEDED. TODAY...LOW CONFIDENCE FORECAST TODAY. THE COLD FRONT AND ASSOCIATED FRONTAL WAVE ARE NOW WELL OFFSHORE WITH A NORTHERLY LOW-LEVEL FLOW DOMINATING IN ITS WAKE. A WEAK POST FRONTAL SURFACE TROUGH DELINEATING A SURGE OF COOLER AIR WILL APPROACH THE CHARLESTON AREA BY SUNRISE...THE SAVANNAH AREA BY MID-MORNING AND FINALLY CLEARING THE ALTAMAHA RIVER BY LATE AFTERNOON. MODELS SHOW A TRANSIENT HYBRID WEDGE SETTING UP ACROSS MAINLY THE CENTRAL AND NORTHERN PORTIONS OF THE FORECAST AREA IN THE WAKE OF THE TROUGH AS 290K ISENTROPIC ASSENT BRIEFLY INTENSIFIES ATOP THE LOW-LEVEL POST FRONTAL WEDGING PATTERN. THIS PATTERN WILL ESSENTIALLY REINFORCE THE WIDESPREAD LOW CLOUDS AND PATCHY DRIZZLE THAT ARE ALREADY IN PLACE ACROSS THE LOWCOUNTRY AND COASTAL EMPIRE FOR A GOOD PORTION OF THE DAY. THE TEMPERATURE FORECAST IS PROVING TO BE EXTREMELY CHALLENGING AS A RESULT AND ASSUMES THE TRANSIENT WEDGE ACTUALLY DEVELOPS AS DEPICTED IN THE HIGHER RESOLUTION DATA SETS. DAILY HIGHS /7AM-6PM/ WILL LIKELY OCCUR BY MID-MORNING ACROSS THE CHARLESTON TRI-COUNTY AREA AND EARLY AFTERNOON ACROSS THE REMAINDER OF SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. TEMPERATURES WILL LIKELY HOLD STEADY OR SLOWLY FALL NORTH THE SAVANNAH RIVER AS THE WEDGE BRIEFING INTENSIFIES. HIGHS WILL RANGE MID 50S NORTH...UPPER 50/NEAR 60 CENTRAL TO THE LOWER-MID 60S SOUTH. UTILIZE A 30/30/30 BLEND OF RAP/H3R AND GLAMP DATA TO CONSTRUCT HOURLY TEMPERATURES. SINCE THIS IS A VERY LOW CONFIDENCE FORECAST...CHANGES--SOME POSSIBLY SIGNIFICANT--WILL LIKELY BE NEEDED THROUGHOUT THE DAY. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... TONIGHT...THE TRANSIENT HYBRID WEDGE WILL QUICKLY BREAKDOWN THIS EVENING AS HIGH PRESSURE FINALLY BRIDGES THE SOUTHERN APPALACHIANS AND BECOMES MORE DOMINATE ACROSS THE SOUTHEAST STATES. A GOOD BIT OF CLOUD COVER WILL LINGER THROUGH THE NIGHT WITH THE POTENTIAL FOR SOME CLEARING TO OCCUR ACROSS THE NORTH AFTER 3 AM. WILL HAVE TO WATCH FOR SOME FOG TO DEVELOP AFTER MIDNIGHT...BUT THIS DOES NOT LOOK SIGNIFICANT AT THIS TIME. LOWS WILL RANGE FROM THE MID- UPPER 30S INTERIOR NORTH WHERE THE BETTER CHANCES FOR CLEARING WILL OCCUR WITH UPPER 30S TO LOWER 40S ELSEWHERE...EXCEPT MID 40S ALONG THE GEORGIA COAST WHERE ONSHORE WINDS WILL MODERATE TEMPERATURES A BIT. WEDNESDAY AND THURSDAY...EXPANSIVE SURFACE HIGH PRESSURE WILL BE GRADUALLY WEAKENING AS IT SLIPS TOWARD THE EAST COAST UNDER RELATIVELY ZONAL FLOW ALOFT. EXPECT DRY CONDITIONS TO PREVAIL WEDNESDAY AND THURSDAY WITHIN THIS PATTERN. TEMPERATURES WEDNESDAY WILL BE A FEW DEGREES COOLER THAN NORMAL...PEAKING IN THE MID TO UPPER 50S DURING THE AFTERNOON AND FALLING INTO THE LOW 30S NORTH TO UPPER 30S COAST AND SOUTH OVERNIGHT. NORTH FLOW WEAKENS ON THURSDAY AS THE CENTER OF THE SURFACE HIGH PASSES DIRECTLY OVER THE REGION...AND WITH SUBTLE RIDGING BUILDING UP FROM THE BAHAMAS...HIGH TEMPERATURES WILL MODERATE TOWARD SEASONAL NORMALS IN THE UPPER 50S TO LOWER 60S. A GRADUALLY IMPROVING TAP INTO GULF MOISTURE LATE THURSDAY WILL SUPPORT INCREASING CLOUDS...WITH LOW TEMPERATURES A FEW DEGREES MILDER IN THE UPPER 30S INLAND TO LOW 40S CLOSER TO THE COAST. FRIDAY...AN UPPER LEVEL CUT OFF LOW WILL MOVE FROM THE SOUTHWEST STATES INTO THE SOUTHERN PLAINS...PROVIDING THE ENERGY TO DEVELOP A WAVE OF LOW PRESSURE ACROSS THE WESTERN GULF LATE IN THE DAY. THE SOUTHEAST STATES WILL REMAIN ON THE PERIPHERY OF ATLANTIC HIGH PRESSURE...WHERE SHORTWAVE ENERGY TRACKING UP FROM THE GULF OF MEXICO WILL SUPPORT THE GRADUAL AMPLIFICATION OF A COASTAL TROUGH. NUMERICAL MODEL SOLUTIONS ARE INDICATING SUFFICIENT ISENTROPIC ASCENT BETWEEN THE COASTAL TROUGH AND A DEVELOPING INLAND WEDGE TO GENERATE ISOLATED TO SCATTERED RAIN...WITH BEST COVERAGE ACROSS NORTHERN AND INLAND AREAS. TEMPERATURES COULD BE A DEGREE OR TWO COOLER THAN THE PREVIOUS DAY GIVEN THE INCREASING CLOUD COVER...YET STILL RANGE NEAR SEASONAL NORMALS IN THE UPPER 50S TO LOW 60S. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... FRIDAY NIGHT THROUGH SUNDAY...A TRANSIENT INLAND WEDGE/COASTAL TROUGH PATTERN WILL BE IN PLACE THROUGH EARLY SATURDAY...BEFORE THE COASTAL TROUGH QUICKLY LIFTS NORTH OF THE REGION AHEAD OF AN APPROACHING COLD FRONT FROM THE WEST. THE CUT OFF LOW ACROSS THE SOUTHERN PLAINS WILL DAMPEN AND LIFT NORTHEAST INTO THE OHIO VALLEY ON SATURDAY. THE ASSOCIATED SURFACE LOW WILL PULL INTO THE NEW ENGLAND STATES SUNDAY...WITH ITS TRAILING COLD FRONT PROGRESSING THROUGH THE MID ATLANTIC AND SOUTHEAST STATES BY SUNDAY AFTERNOON. HIGH TEMPERATURES WILL SURGE INTO THE 60S TO AROUND 70 DEGREES SATURDAY AND SUNDAY WITHIN WARM SOUTHERLY FLOW AHEAD OF THE FRONT...WHILE SCATTERED SHOWERS ARE POSSIBLE SATURDAY THROUGH SUNDAY AFTERNOON. PREFER TO REMAIN RATHER CONSERVATIVE WITH RAIN CHANCES AT THIS POINT...CONSIDERING THE SOUTHERN END OF THE FRONT WILL RUN INTO THE PERIPHERY OF THE SUBTROPICAL RIDGE AND BECOME PARALLEL TO FLOW ALOFT. SUNDAY NIGHT THROUGH TUESDAY...SURFACE HIGH PRESSURE WILL BUILD IN THE WAKE OF THE DEPARTING COLD FRONT EARLY NEXT WEEK...EVENTUALLY SETTLING TO THE NORTH OF THE AREA. RAIN FREE CONDITIONS WILL PREVAIL. TEMPERATURES ARE EXPECTED TO RETURN TO SEASONAL NORMALS...POSSIBLY COOLER IF A WEDGE PATTERN CAN SET UP TOWARD THE END OF THE FORECAST PERIOD. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... LIFR CIGS WILL LINGER AT BOTH TERMINALS THROUGH SUNRISE. CIGS WILL REMAIN BELOW ALTERNATE MINIMUMS AND COULD DROP BELOW AIRPORT MINIMUMS OVER THE NEXT FEW HOURS. FOG COULD BECOME A PROBLEM LATE...BUT THE LOW CIGS WILL BE THE PRIMARY ISSUE UNLESS THE STRATUS DECKS REACH THE GROUND RESULTING IN DENSE FOG. LOW CONFIDENCE IN THIS SCENARIO RIGHT NOW. CIGS WILL LIFT EVER SO SLOWLY AFTER SUNRISE...BUT SHOULD RISE ABOVE ALTERNATE MINIMUMS 13-14Z...ALTHOUGH STAYING IN IFR. MVFR SHOULD RETURN BY 16-17Z AND LINGER THE REST OF THE 06Z TAF PERIOD. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL WEDNESDAY AND THURSDAY. CHANCES FOR FLIGHT RESTRICTIONS INCREASE INTO THE WEEKEND AS THE NEXT SYSTEM IMPACTS THE REGION. && .MARINE... TODAY...CEILINGS OF 100 FT AT THE HILTON HEAD AIRPORT AND WEBCAMS IN THE SAVANNAH RIVER AS WELL AS TYBEE ISLAND SUGGEST SEA FOG IS IN PLACE ACROSS THE COASTAL WATERS THIS MORNING. IT IS UNCLEAR EXACTLY HOW WIDESPREAD THE FOG IS...BUT RAP VISIBILITIES DATA SUGGEST ITS PROBABLY PRETTY WIDESPREAD. WFO JAX RECENTLY RELAYED THAT THE BAR PILOTS OUT OF SAINT SIMMONS ARE REPORTING IMPROVED VSBYS OVER THE PAST HOUR...BUT THE SHELF WATERS OFF TYBEE ISLAND ARE SEVERAL DEGREES COOLER. PREFER TO HOLD THE MARINE DENSE FOG ADVISORY FOR THE GEORGIA NEARSHORE AND BEAUFORT COUNTY WATERS UNTIL 8 AM...OR AT LEAST UNTIL CONDITIONS CAN BE BETTER EVALUATED ON COASTAL WEBCAMS AS THE SUN RISES. OTHERWISE...NORTH WINDS WILL INCREASE TO 10-15 KT TODAY WITH SEAS 1-3 FT. TONIGHT...WINDS WILL INCREASE A BIT AS THE PRESSURE GRADIENT INDUCED BY HIGH PRESSURE BUILDING IN FROM THE WEST TIGHTENS. EXPECT WINDS OF 15-20 KT WITH SEAS 2-3 FT NEARSHORE...4-5 FT OFFSHORE. WEDNESDAY THROUGH SATURDAY...THE PRESSURE GRADIENT WILL REMAIN RELATIVELY TIGHT INTO WEDNESDAY MORNING ON THE PERIPHERY OF HIGH PRESSURE BUILDING FROM THE WEST. MARGINAL SMALL CRAFT ADVISORY WINDS IN GUSTS TO 25 KT COULD LINGER ACROSS THE OFFSHORE GEORGIA WATERS...BEFORE CONDITIONS SLOWLY IMPROVE AS THE DAY PROGRESSES. THE SURFACE HIGH WILL THEN STEADILY TRACK EAST AND ALLOW THE GRADIENT TO RELAX TOWARD THE END OF THE WEEK. A COASTAL TROUGH WILL DEVELOP LATE FRIDAY INTO SATURDAY...WITH INCREASING SOUTHERLY FLOW IN IT WAKE. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR GAZ118-119. SC...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR SCZ047>049- 051. MARINE...DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR AMZ352-354. && $$ ST/WMS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
129 AM EST TUE DEC 30 2014 .SYNOPSIS... A COLD FRONT WILL MOVE SOUTHEAST INTO THE ATLANTIC EARLY TONIGHT AND PUSH FURTHER OFFSHORE OVERNIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY INTO FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL TROUGH WILL DEVELOP EARLY THIS WEEKEND THEN LIFT NORTH OF THE REGION ON SUNDAY. A COLD FRONT WILL THEN PASS OFF THE COAST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... WEAK COLD FRONT HAS CLEARED THE GEORGIA COAST WITH A PRONOUNCED POST-FRONTAL SURFACE TROUGH DROPPING SOUTH. THE TROUGH HAS PASSED THE CHARLESTON AIRPORT AND WILL CONTINUE TO MOVE SLOWLY SOUTH THROUGH SUNRISE. LOW STRATUS AND EVENTUALLY FOG WILL AFFECT THE REGION OVERNIGHT WITH OCCASIONAL LIGHT DRIZZLE. SKIES HAVE CLEARED BRIEFLY ACROSS ALLENDALE COUNTY AND DENSE RADIATION FOG HAS QUICKLY DEVELOPED. ITS UNCLEAR HOW LONG THE DENSE FOG WILL LAST...BUT IT MAY BE ANOTHER 1-2 HOURS BEFORE LOW CLOUDS FILL IN FROM THE NORTH. IN FACT...CLEARING AND DENSE FOG COULD OCCUR ACROSS MUCH OF THE FAR WESTERN ZONES FOR THE NEXT FEW HOURS. WILL WATCH TRENDS CAREFULLY. OTHERWISE...DRIZZLE AND EXTENSIVE CLOUD COVER WILL PERSIST. IT IS UNCLEAR HOW STRONG POST-FRONTAL STRATUS BUILD DOWN WILL BE...BUT THERE IS A POTENTIAL FOR SOME DENSE FOG. MADE ADJUSTMENTS TO CLOUD COVER...FOG COVERAGE AND INTRODUCED AREAS OF DRIZZLE INTO THE FORECAST FOR THE MIDNIGHT UPDATE. THE REST OF THE FORECAST IS OKAY. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/... TUESDAY AND TUESDAY NIGHT...NEARLY ZONAL FLOW WILL PREVAIL ALOFT AS A COLD FRONT SLIPS OFF SHORE. BACK TO THE WEST...CONFLUENT FLOW ALOFT WILL HELP TO FORCE AN IMPRESSIVE 1058 MB HIGH OVER THE NORTHERN ROCKIES THAT WILL BUILD INTO THE FORECAST AREA THROUGH THE DAY. FOLLOWING LOW LEVEL THETA E FIELDS...THE LEADING EDGE OF THE COOLER AIR BEHIND THE FRONT AND THE EXTENT OF THE STRONG SURFACE HIGH WILL NOT OOZE INTO THE AREA UNTIL LATER IN THE DAY ON TUESDAY AND POSSIBLY EVEN INTO THE EVENING. AHEAD OF THIS THETA E GRADIENT...RESIDUAL MOISTURE IN THE LOWEST 3-4K FT OF THE ATMOSPHERE SHOWS UP WELL IN MODEL TIME HEIGHTS AND CROSS SECTIONS. THIS SHOULD MANIFEST ITSELF IN THE FORM OF EXTENSIVE STRATUS ACROSS THE FORECAST AREA FOR MUCH OF THE DAY. IN FACT...WE MAY NOT SEE ANY CLEARING IN THE TRI-COUNTY REGION UNTIL LATE IN THE AFTERNOON. THIS WILL HELP KEEP TEMPERATURES AT BAY DESPITE THE LATER ARRIVAL OF THE COOLER AIR. LOOK FOR HIGHS IN THE MID/UPPER 50S FURTHER NORTH...AND LOW 60S FURTHER TO THE SOUTH. SOME OF THE MODELS ARE WRINGING OUT SOME MEASURABLE PRECIPITATION IN THE MORNING DESPITE THE LACK OF FORCING AND RELATIVELY SHALLOW MOIST LAYER. HAVE KEPT THE FORECAST DRY. OVERNIGHT...COOL NORTHERLY FLOW WILL SETTLE IN AS THE LOW LEVELS START TO DRY OUT. THE FORECAST IS DRY AND FEATURES LOWS FALLING INTO THE UPPER 30S NORTH...LOW 40S FURTHER SOUTH FOR COASTAL SOUTHEAST GEORGIA. WEDNESDAY THROUGH THURSDAY...ZONAL FLOW WILL PREVAIL ALOFT AS EXPANSIVE BUT WEAKENING HIGH PRESSURE BUILDS IN FROM THE WEST. WE MAY BE DEALING WITH A DECENT AMOUNT OF JET-INDUCED HIGH CLOUDS ON WEDNESDAY...BUT A COLUMN THAT IS OVERALL VERY DRY WILL KEEP THE FORECAST RAIN FREE THROUGH THURSDAY. TEMPERATURES WILL BE ON THE COOL SIDE WEDNESDAY...RUNNING ABOUT 4 DEGREES BELOW NORMAL...THEN RIGHT AROUND NORMAL ON THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... THE EXPANSIVE SURFACE HIGH WILL STEADILY SHIFT OVER GEORGIA AND THE CAROLINAS BY FRIDAY...BEFORE MOVING INTO THE ATLANTIC WATERS SATURDAY. A STRONG CUT OFF LOW OVER THE DESERT SOUTHWEST FRIDAY WILL EJECT INTO THE SOUTHERN PLAINS OVER THE WEEKEND AND THEN DAMPEN AS IT MOVE INTO THE UPPER GULF COAST REGION BY LATE WEEKEND. CLOUDS WILL BE ON THE INCREASE THURSDAY NIGHT AS A SHORT WAVES TRAVERSES INTO THE REGION ATOP A LARGE SUBTROPICAL RIDGE OVER FLORIDA AND THE CARIBBEAN. THIS DISTURBANCE MAY PRODUCE SOME SPOTTY LIGHT RAINS ON FRIDAY BUT CERTAINLY NOT SIGNIFICANT AS PRECIP IS LIKELY TO EVAPORATE IN DRY LAYERS BELOW 10 KFT. A SLIGHT CHANCE POP LOOKS QUITE SUFFICIENT. STEADIER RAINS ACROSS NORTH GEORGIA AND THE WESTERN CAROLINAS MAY BEGIN TO ANCHOR A WEDGE ON SATURDAY WITH GLOBAL MODELS DIFFERING ON SURFACE PATTERNS. THE WEEKEND LOOKS A BIT UNSETTLED WITH PLENTY OF CLOUDS MOST AREAS AND MAINLY LOW END CHANCE POPS AS THE UPPER WAVE FLATTENS SIGNIFICANTLY LATE IN THE WEEKEND. SUNDAY APPEARS TO BE THE WARMER OF THE DAYS AFTER WE TRENDED DOWN A GOOD BIT ON TEMPS NORTHERN ZONES SATURDAY. A COLD FRONT SHOULD MOVE OFF THE COAST EARLY NEXT WEEK. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... LIFR CIGS WILL LINGER AT BOTH TERMINALS THROUGH SUNRISE. CIGS WILL REMAIN BELOW ALTERNATE MINIMUMS AND COULD DROP BELOW AIRPORT MINIMUMS OVER THE NEXT FEW HOURS. FOG COULD BECOME A PROBLEM LATE...BUT THE LOW CIGS WILL BE THE PRIMARY ISSUE UNLESS THE STRATUS DECKS REACH THE GROUND RESULTING IN DENSE FOG. LOW CONFIDENCE IN THIS SCENARIO RIGHT NOW. CIGS WILL LIFT EVER SO SLOWLY AFTER SUNRISE...BUT SHOULD RISE ABOVE ALTERNATE MINIMUMS 13-14Z...ALTHOUGH STAYING IN IFR. MVFR SHOULD RETURN BY 16-17Z AND LINGER THE REST OF THE 06Z TAF PERIOD. EXTENDED AVIATION OUTLOOK...LOW CEILINGS TO CLEAR OUT TUESDAY NIGHT...IF NOT BEFORE. VFR CONDITIONS WILL THEN PREVAIL THROUGH AT LEAST THURSDAY. CHANCES FOR FLIGHT RESTRICTIONS INCREASE INTO THE WEEKEND AS THE NEXT SYSTEM IMPACTS THE REGION. && .MARINE... TONIGHT...CEILINGS AT HILTON HEAD HAVE DROPPED TO 100 FT... SUGGESTING DENSE FOG IN OCCURRING JUST OFFSHORE. EXPANDED THE MARINE DENSE FOG ADVISORY NORTH TO INCLUDE THE BEAUFORT COUNTY WATERS. WEBCAMS OUT OF TYBEE ISLAND AND EARLIER REPORTS FROM THE SAINT SIMMONS BAR PILOT BOAT PROVIDE ENOUGH DATA TO SUPPORT A MARINE DENSE FOG ADVISORY FOR THE GEORGIA NEARSHORE WATERS THROUGH 6 AM. RAP VSBY PROGS APPEAR TO CAPTURE THE SEA FOG WELL AND WAS USED TO CONSTRUCT WEATHER AND VSBY GRIDS THROUGH 6 AM. TUESDAY THROUGH SATURDAY...A COLD FRONT WILL PUSH WELL OFFSHORE TUESDAY AS HIGH PRESSURE WILL BEGIN TO BUILD IN TUESDAY NIGHT. AS THE HIGH BUILDS IN A NOTABLE NORTHERLY SURGE WILL TAKE PLACE TUESDAY NIGHT AND INTO WEDNESDAY MORNING. A SOLID 15-20 KT OF WIND IS EXPECTED WITHIN 20 NM WITH SOME GUSTS TO 25 KT POSSIBLE. WINDS WILL BE CLOSER TO 20-25 KT FOR THE OUTER GEORGIA WATERS WITH SOME 6 FT SEAS POSSIBLE. SMALL CRAFT ADVISORIES MAY BE NEEDED...ESPECIALLY FOR THE OUTER GEORGIA WATERS TUESDAY NIGHT. THEREAFTER...HIGH PRESSURE WILL BE THE PRIMARY WEATHER FEATURE THOUGH THE GRADIENT WILL RELAX. IT IS STILL A BIT TOO EARLY TO COMMIT ON STRENGTH OF THE WEDGE THIS WEEKEND AND TIMING THE WARM FRONT THROUGH...BUT COMPLEX LOW LEVEL MIXING ENVIRONMENTS ARE LIKELY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR AMZ352-354. && $$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1240 AM EST TUE DEC 30 2014 .SYNOPSIS... A COLD FRONT WILL MOVE SOUTHEAST INTO THE ATLANTIC EARLY TONIGHT AND PUSH FURTHER OFFSHORE OVERNIGHT. HIGH PRESSURE WILL BUILD INTO THE AREA TUESDAY INTO FRIDAY...BEFORE MOVING INTO THE ATLANTIC BY SATURDAY. A COASTAL TROUGH WILL DEVELOP EARLY THIS WEEKEND THEN LIFT NORTH OF THE REGION ON SUNDAY. A COLD FRONT WILL THEN PASS OFF THE COAST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... WEAK COLD FRONT HAS CLEARED THE GEORGIA COAST WITH A PRONOUNCED POST-FRONTAL SURFACE TROUGH DROPPING SOUTH. THE TROUGH HAS PASSED THE CHARLESTON AIRPORT AND WILL CONTINUE TO MOVE SLOWLY SOUTH THROUGH SUNRISE. LOW STRATUS AND EVENTUALLY FOG WILL AFFECT THE REGION OVERNIGHT WITH OCCASIONAL LIGHT DRIZZLE. SKIES HAVE CLEARED BRIEFLY ACROSS ALLENDALE COUNTY AND DENSE RADIATION FOG HAS QUICKLY DEVELOPED. ITS UNCLEAR HOW LONG THE DENSE FOG WILL LAST...BUT IT MAY BE ANOTHER 1-2 HOURS BEFORE LOW CLOUDS FILL IN FROM THE NORTH. IN FACT...CLEARING AND DENSE FOG COULD OCCUR ACROSS MUCH OF THE FAR WESTERN ZONES FOR THE NEXT FEW HOURS. WILL WATCH TRENDS CAREFULLY. OTHERWISE...DRIZZLE AND EXTENSIVE CLOUD COVER WILL PERSIST. IT IS UNCLEAR HOW STRONG POST-FRONTAL STRATUS BUILD DOWN WILL BE...BUT THERE IS A POTENTIAL FOR SOME DENSE FOG. MADE ADJUSTMENTS TO CLOUD COVER...FOG COVERAGE AND INTRODUCED AREAS OF DRIZZLE INTO THE FORECAST FOR THE MIDNIGHT UPDATE. THE REST OF THE FORECAST IS OKAY. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/... TUESDAY AND TUESDAY NIGHT...NEARLY ZONAL FLOW WILL PREVAIL ALOFT AS A COLD FRONT SLIPS OFF SHORE. BACK TO THE WEST...CONFLUENT FLOW ALOFT WILL HELP TO FORCE AN IMPRESSIVE 1058 MB HIGH OVER THE NORTHERN ROCKIES THAT WILL BUILD INTO THE FORECAST AREA THROUGH THE DAY. FOLLOWING LOW LEVEL THETA E FIELDS...THE LEADING EDGE OF THE COOLER AIR BEHIND THE FRONT AND THE EXTENT OF THE STRONG SURFACE HIGH WILL NOT OOZE INTO THE AREA UNTIL LATER IN THE DAY ON TUESDAY AND POSSIBLY EVEN INTO THE EVENING. AHEAD OF THIS THETA E GRADIENT...RESIDUAL MOISTURE IN THE LOWEST 3-4K FT OF THE ATMOSPHERE SHOWS UP WELL IN MODEL TIME HEIGHTS AND CROSS SECTIONS. THIS SHOULD MANIFEST ITSELF IN THE FORM OF EXTENSIVE STRATUS ACROSS THE FORECAST AREA FOR MUCH OF THE DAY. IN FACT...WE MAY NOT SEE ANY CLEARING IN THE TRI-COUNTY REGION UNTIL LATE IN THE AFTERNOON. THIS WILL HELP KEEP TEMPERATURES AT BAY DESPITE THE LATER ARRIVAL OF THE COOLER AIR. LOOK FOR HIGHS IN THE MID/UPPER 50S FURTHER NORTH...AND LOW 60S FURTHER TO THE SOUTH. SOME OF THE MODELS ARE WRINGING OUT SOME MEASURABLE PRECIPITATION IN THE MORNING DESPITE THE LACK OF FORCING AND RELATIVELY SHALLOW MOIST LAYER. HAVE KEPT THE FORECAST DRY. OVERNIGHT...COOL NORTHERLY FLOW WILL SETTLE IN AS THE LOW LEVELS START TO DRY OUT. THE FORECAST IS DRY AND FEATURES LOWS FALLING INTO THE UPPER 30S NORTH...LOW 40S FURTHER SOUTH FOR COASTAL SOUTHEAST GEORGIA. WEDNESDAY THROUGH THURSDAY...ZONAL FLOW WILL PREVAIL ALOFT AS EXPANSIVE BUT WEAKENING HIGH PRESSURE BUILDS IN FROM THE WEST. WE MAY BE DEALING WITH A DECENT AMOUNT OF JET-INDUCED HIGH CLOUDS ON WEDNESDAY...BUT A COLUMN THAT IS OVERALL VERY DRY WILL KEEP THE FORECAST RAIN FREE THROUGH THURSDAY. TEMPERATURES WILL BE ON THE COOL SIDE WEDNESDAY...RUNNING ABOUT 4 DEGREES BELOW NORMAL...THEN RIGHT AROUND NORMAL ON THURSDAY. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... THE EXPANSIVE SURFACE HIGH WILL STEADILY SHIFT OVER GEORGIA AND THE CAROLINAS BY FRIDAY...BEFORE MOVING INTO THE ATLANTIC WATERS SATURDAY. A STRONG CUT OFF LOW OVER THE DESERT SOUTHWEST FRIDAY WILL EJECT INTO THE SOUTHERN PLAINS OVER THE WEEKEND AND THEN DAMPEN AS IT MOVE INTO THE UPPER GULF COAST REGION BY LATE WEEKEND. CLOUDS WILL BE ON THE INCREASE THURSDAY NIGHT AS A SHORT WAVES TRAVERSES INTO THE REGION ATOP A LARGE SUBTROPICAL RIDGE OVER FLORIDA AND THE CARIBBEAN. THIS DISTURBANCE MAY PRODUCE SOME SPOTTY LIGHT RAINS ON FRIDAY BUT CERTAINLY NOT SIGNIFICANT AS PRECIP IS LIKELY TO EVAPORATE IN DRY LAYERS BELOW 10 KFT. A SLIGHT CHANCE POP LOOKS QUITE SUFFICIENT. STEADIER RAINS ACROSS NORTH GEORGIA AND THE WESTERN CAROLINAS MAY BEGIN TO ANCHOR A WEDGE ON SATURDAY WITH GLOBAL MODELS DIFFERING ON SURFACE PATTERNS. THE WEEKEND LOOKS A BIT UNSETTLED WITH PLENTY OF CLOUDS MOST AREAS AND MAINLY LOW END CHANCE POPS AS THE UPPER WAVE FLATTENS SIGNIFICANTLY LATE IN THE WEEKEND. SUNDAY APPEARS TO BE THE WARMER OF THE DAYS AFTER WE TRENDED DOWN A GOOD BIT ON TEMPS NORTHERN ZONES SATURDAY. A COLD FRONT SHOULD MOVE OFF THE COAST EARLY NEXT WEEK. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... LIFR CIGS WILL LINGER AT BOTH TERMINALS THROUGH SUNRISE. CIGS WILL REMAIN BELOW ALTERNATE MINIMUMS AND COULD DROP BELOW AIRPORT MINIMUMS OVER THE NEXT FEW HOURS. FOG COULD BECOME A PROBLEM LATE...BUT THE LOW CIGS WILL BE THE PRIMARY ISSUE UNLESS THE STRATUS DECKS REACH THE GROUND RESULTING IN DENSE FOG. LOW CONFIDENCE IN THIS SCENARIO RIGHT NOW. CIGS WILL LIFT EVER SO SLOWLY AFTER SUNRISE...BUT SHOULD RISE ABOVE ALTERNATE MINIMUMS 13-14Z...ALTHOUGH STAYING IN IFR. MVFR SHOULD RETURN BY 16-17Z AND LINGER THE REST OF THE 06Z TAF PERIOD. EXTENDED AVIATION OUTLOOK...LOW CEILINGS TO CLEAR OUT TUESDAY NIGHT...IF NOT BEFORE. VFR CONDITIONS WILL THEN PREVAIL THROUGH AT LEAST THURSDAY. CHANCES FOR FLIGHT RESTRICTIONS INCREASE INTO THE WEEKEND AS THE NEXT SYSTEM IMPACTS THE REGION. && .MARINE... TONIGHT...WEBCAMS OUT OF TYBEE ISLAND AND EARLIER REPORTS FROM THE SAINT SIMMONS BAR PILOT BOAT PROVIDE ENOUGH DATA TO SUPPORT A MARINE DENSE FOG ADVISORY FOR THE GEORGIA NEARSHORE WATERS THROUGH 6 AM. RAP VSBY PROGS APPEAR TO CAPTURE THE SEA FOG WELL AND WAS USED TO CONSTRUCT WEATHER AND VSBY GRIDS THROUGH 6 AM. TUESDAY THROUGH SATURDAY...A COLD FRONT WILL PUSH WELL OFFSHORE TUESDAY AS HIGH PRESSURE WILL BEGIN TO BUILD IN TUESDAY NIGHT. AS THE HIGH BUILDS IN A NOTABLE NORTHERLY SURGE WILL TAKE PLACE TUESDAY NIGHT AND INTO WEDNESDAY MORNING. A SOLID 15-20 KT OF WIND IS EXPECTED WITHIN 20 NM WITH SOME GUSTS TO 25 KT POSSIBLE. WINDS WILL BE CLOSER TO 20-25 KT FOR THE OUTER GEORGIA WATERS WITH SOME 6 FT SEAS POSSIBLE. SMALL CRAFT ADVISORIES MAY BE NEEDED...ESPECIALLY FOR THE OUTER GEORGIA WATERS TUESDAY NIGHT. THEREAFTER...HIGH PRESSURE WILL BE THE PRIMARY WEATHER FEATURE THOUGH THE GRADIENT WILL RELAX. IT IS STILL A BIT TOO EARLY TO COMMIT ON STRENGTH OF THE WEDGE THIS WEEKEND AND TIMING THE WARM FRONT THROUGH...BUT COMPLEX LOW LEVEL MIXING ENVIRONMENTS ARE LIKELY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR AMZ354. && $$ ST
AREA FORECAST DISCUSSION
NWS POCATELLO ID
155 PM MST TUE DEC 30 2014 .SHORT TERM...TONIGHT THROUGH FRIDAY. AN AMPLIFIED RIDGE OF HIGH PRESSURE WILL PREVAIL ALONG THE PAC COAST THROUGH THURSDAY MAINTAINING THE COLD ARCTIC NNE FLOW ACROSS THE REGION. THUS WIND CHILL WARNINGS WILL CONTINUE ACROSS THE UPPER SNAKE RIVER PLAIN/HIGHLANDS AND ADJOINING TRIBUTARIES WHERE ELEVATED WIND SPEEDS WILL CREATE DANGEROUSLY COLD WIND CHILL VALUES. VALLEY FOG AND LOW CLOUDS OVER BOISE/MOUNTAIN HOME MAY CONTINUE TO BACK UP THE VALLEY INTO THE LOWER SNAKE RIVER PLAIN/ERN MAGIC VALLEY OVERNIGHT WHICH MAY ALSO HELP TO MODERATE THE FRIGIDLY COLD TEMPS IN THAT AREA. BY FRIDAY...THE RIDGE WEAKENS AS A PAC STORM BREAKS INTO WRN CANADA ENCOURAGING DAYTIME HIGH TEMPERATURES TO WARM TO NEAR NORMAL LEVELS. HUSTON .LONG TERM...FRIDAY NIGHT THROUGH NEXT TUESDAY NIGHT. TWO SHORTWAVES EXPECTED TO MOVE THROUGH CENTRAL AND EASTERN IDAHO...ONE ON THE VERY FIRST PERIOD (FRI NIGHT)...AND A SECOND FROM LATE SUN THROUGH MON. THEY BOTH AFFECT MAINLY THE NORTHERN HALF OF THE FORECAST AREA...WITH NEARLY ZERO PRECIPITATION EXPECTED IN THE SOUTH CENTRAL HIGHLANDS AND PARTS OF THE EASTERN MAGIC VALLEY. TERRAIN EFFECTS ARE STRONG...WITH A LIGHT SNOW EVENT EXPECTED IN THE SNAKE RIVER PLAIN...BUT MODERATE RIGHT NOW FOR THE MOUNTAINS. BY THE END OF THE PERIOD...AN UPPER LEVEL RIDGE BEGINS TO BUILD INTO SOUTHERN IDAHO. THIS PUSHES THE STORM TRACK FARTHER NORTH AND AWAY FROM THE GEM STATE. THERE IS A SHORTWAVE THAT ARRIVES IN THE FINAL 24 HOURS OF THE FORECAST THAT MAY BRUSH THE IDAHO-MONTANA BORDER REGION...BUT ITS EFFECTS SHOULD BE SLIGHT. THE UPPER LEVEL LONG WAVE PATTERN IS ALSO SHIFTING IN THIS WAY...REINFORCING THE LIKELIHOOD OF THE RIDGE BUILDING INTO IDAHO FOR A DRIER END TO THIS PERIOD. MESSICK && .AVIATION...ARCTIC AIR HAS MOVED IN AND STABILIZED...SO NOT LOOKING FOR THE GUSTY WIND AGAIN TONIGHT...ALTHOUGH AMBIENT TEMPERATURES WILL ACTUALLY BE COLDER. THE MAIN FORECAST PROBLEM THOUGH IS WHETHER OR NOT THE STRATUS EXPECTED BY MOS GUIDANCE WILL APPEAR OR NOT. TIME-HEIGHT CROSS SECTIONS DO NOT HAVE ANY BOUNDARY LAYER HUMIDITY THAT EXCEEDS 90 PERCENT EXCEPT FOR KBYI. THIS MORNING THERE WAS A LARGE STRATUS AREA IN THE TREASURE VALLEY AND WESTERN MAGIC VALLEY...SO IT IS A CONCERN THAT THE STRATUS COULD SPREAD FROM THERE INTO THE EASTERN MAGIC VALLEY AND KBYI. THE HRRR AND NAM NOW INDICATE THAT THE EASTERLY WIND WILL WEAKEN AT KBYI AND GO LIGHT AND VARIABLE AFTER 31/07Z OR SO...SO THIS WOULD LIKELY BE THE TIME OF ARRIVAL OF ANY STRATUS. HAVE UPDATED TO PUT THIS INTO THE KBYI TAF. THE OTHER TWO LOW ELEVATION AIRPORTS COULD STILL EXPERIENCE SOME STRATUS...BUT BOUNDARY LAYER HUMIDITY IS NOT AS GOOD...SO HAVE PUT IN A FEW CLOUDS BELOW 1000 FT. KSUN WAS EXPECTED TO BE IN THE CLEAR...BUT AN AREA OF STRATUS HAS MOVED THROUGH THE SAWTOOTHS AND IS LYING JUST TO THE SOUTH OF THE KSUN AIRDROME. ANY RETURN TO A SOUTHERLY COMPONENT TO THE WIND AT KSUN COULD ADVECT THE STRATUS INTO THE AIRPORT AREA. ONCE WIND THERE SWITCHES BACK TO NORTHWEST DURING THE EARLY EVENING...THIS SHOULD END THE THREAT TO THE CIG AT KSUN. MESSICK && .PIH WATCHES/WARNINGS/ADVISORIES... WIND CHILL WARNING CONTINUES UNTIL NOON WEDNESDAY IDZ019. WIND CHILL WARNING FROM 8 PM MST THIS EVENING UNTIL NOON WEDNESDAY IDZ020-021-032. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
229 AM CST TUE DEC 30 2014 .SHORT TERM... 229 AM CST THROUGH WEDNESDAY... ONE WORD SUMS UP THE ENTIRE SHORT TERM FORECAST: COLD. SOMEWHAT MODIFIED ARCTIC AIR IS SEEPING SOUTH AND SHOULD SET THE STAGE FOR SEASONABLY COLD CONDITIONS THE NEXT COUPLE DAYS. THE LACK OF SNOW COVER HERE OR IMMEDIATELY UPSTREAM SHOULD ALLOW THE AIR MASS TO MODIFY SOME AND WE CERTAINLY WILL NOT BE ANYWHERE NEAR AS COLD AS IT WOULD BE WITH SNOW COVER. STRONG LOW PRESSURE WILL DROP SOUTH INTO HUDSON BAY WEDNESDAY AND WE COMBINED WITH THE STRONG HIGH TO OUR SOUTH WILL SET THE STAGE FOR AN INCREASINGLY WINDY DAY WEDNESDAY...SO EVEN THOUGH TEMPERATURES WILL BE IN THE SAME BALLPARK AS TODAY ON WEDNESDAY THE STRONG WINDS WILL MAKE IT FEEL COLDER WITH WIND CHILLS HOVERING NEAR ZERO OR EVEN A BIT BELOW ALL DAY AND INTO NEW YEARS EVE NIGHT. IZZI && .LONG TERM... 229 AM CST WEDNESDAY NIGHT THROUGH MONDAY... TROUGH OVER THE REGION WILL RETREAT WITH RISING HEIGHTS AND MODERATING TEMPERATURES THURSDAY AND FRIDAY WITH GENERALLY DRY CONDITIONS. IN THE LONGER TERM ALL EYES WILL BE ON WHAT BECOMES OF THE POWERFUL CUT OFF SYSTEM OVER THE SOUTHWEST. MEDIUM RANGE MODELS CONTINUE TO WAFFLE AROUND WITH TIMING...TRACK...AND INTENSITY VARYING FROM RUN TO RUN AND MODEL TO MODEL. THESE TYPE OF SYSTEMS ARE NOT WELL HANDLED BY NUMERICAL GUIDANCE AND WOULD EXPECT CONTINUE MODEL VARIANCES...SOME POSSIBLY SIGNIFICANT...IN THE COMING DAYS SO AM NOT WILLING TO STRAY FROM THE BLENDED MODEL GUIDANCE WITH LOW POPS AND RAIN OR SNOW FOR P-TYPE. DOES LOOK LIKE MORE COLD AIR WILL PROBABLY SPILL INTO THE AREA BEHIND THAT SOUTHWESTERN SYSTEM WHEN EVER IT DOES END UP PASSING BY. IZZI && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * NORTH-NORTHWEST WINDS 10 KT OR HIGHER GRADUALLY SHIFTING WEST LATER TODAY. //DISCUSSION...UPDATED 06Z... ISOLATED MVFR CIGS ARE LARGELY PASSING SOUTH OF A KVYS-KMGC LINE...WITH A VFR DECK SLIDING SE THROUGH THE AREA THIS EVENING. THE VFR DECK WILL CONTINUE MOVING SE AND SHOULD CLEAR THE AREA BY DAYBREAK...WITH ANY ADDITIONAL LAKE INDUCED MVFR TO BE EAST OF KGYY. ONLY CLOUDS LEFT WILL BE PASSING HIGH CLOUDS FROM A LOW IN COLORADO. OTHERWISE...HIGH PRESSURE NOSES SOUTH INTO THE PLAINS TODAY WHICH WILL ALONG NORTH- NORTHWEST WINDS TO TAKE ON A MORE WESTERLY COMPONENT THROUGH THE DAY...LARGELY STAYING FROM 9-12 KT THROUGH THE PERIOD. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM-HIGH IN WINDS. //OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z... WEDNESDAY...VFR. STIFF SOUTHWEST WINDS. THURSDAY-FRIDAY...VFR. WEST-SOUTHWEST WINDS. SATURDAY-SUNDAY...CHANCE OF SNOW AND IFR. MTF && .MARINE... 304 PM CST NORTH TO NORTHWEST WINDS PERSIST ACROSS THE LAKE TONIGHT...THEN GRADUALLY BACK SOUTHWEST BY WEDNESDAY AND INCREASE TO GALES BY WEDNESDAY AFTERNOON OR EVENING. IT IS NOT CERTAIN HOW EFFECTIVELY THESE SOMEWHAT MILDER SOUTHWEST WINDS WILL SUPPORT STRONG GALES OVER THE COLD WATER...BUT GALES DO APPEAR LIKELY. UNTIL WINDS TURN AWAY FROM NORTH AND NORTHWEST...CONDITIONS WILL BE FAVORABLE FOR SMALL CRAFT HEADLINES FOR THE FIRST HALF OF THE WEEK...AND ESPECIALLY IN THE INDIANA NEARSHORE WATERS. LENNING && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL MIDNIGHT WEDNESDAY. GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567- LMZ868...9 AM WEDNESDAY TO 3 AM THURSDAY. GALE WATCH...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779- LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...NOON WEDNESDAY TO 3 AM THURSDAY. && $$ 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 1128 PM CST Mon Dec 29 2014 .UPDATE... ISSUED AT 900 PM CST MON DEC 29 2014 The lift being generated in the post frontal airmass has been very weak, based on radar returns and local observations. Have only seen isolated reports of flurries so far. A clearing line just north of the band of clouds/flurries is progressing southward, which would spell an end to the very narrow channel of lift/clouds/flurries. Have updated the sky grids to account for some clearing later tonight at least across the northern counties. Less cloud cover would mean colder lows that we currently have, a bit more toward the colder guidance numbers. Have trimmed a few degrees from lows NW of a line from SPI to BMI. Will keep a mention of flurries in tonight`s forecast following the trek of the band of clouds to the SE. No other significant changes needed this evening. Tomorrow looks like a colder but mostly sunny day. Updated info will be available shortly. && .SHORT TERM...(Tonight) ISSUED AT 315 PM CST MON DEC 29 2014 The 18Z surface analysis indicated the leading edge of the Arctic airmass, ahead of an intense high pressure center in the Canadian Rockies, was sinking just south of I-80. Clouds associated with cold air undercutting were along the I-74 corridor at 20z/2 pm CST. This area of cloudiness, along with low clouds in southern Iowa/northern Missouri will overspread central and eventually southeast Illinois this evening. There should be enough weak forcing for snow flurries, particularly in central Illinois this evening, and the rest of the forecast area late tonight as the short range models point to weak lift just behind the strongest low level cold advection. The HRRR model is trying to produce some measurable snow from Bloomington to near Taylorville between 6 pm and Midnight. At this point, it is the only model, doing this and has most likely latched on to the area of light snow around Pontiac. Will keep an eye on this, but for now will stick to the mention of flurries. The numerical guidance appears to be on the colder side due to less cloud cover and stronger cold advection. Thus, will be going with lows roughly 5 degrees warmer than guidance in central IL and 2-3 degrees warmer in southeast IL due to forecast cloud cover. && .LONG TERM...(Tuesday through Monday) ISSUED AT 315 PM CST MON DEC 29 2014 The narrow band of flurries will continue into Tuesday morning, but should dissipate by afternoon. Behind this area, and strong 1050mb high pressure area will drop into the region. This high will bring dry weather to the area through Thur night, as well as well below normal temps through the period. With the center of the high dropping into the plains Tue night, the coldest temps are expected to be Tue night through Wed. Northwesterly winds Tue night will still be around 10mph, so there could be enough mixing to prevent the bottom from dropping out on the temps. However, single digits are still expected over half of the CWA, and combined with the wind speeds, below zero wind chills are probably Tue night/Wed morning. Beyond this, the high pressure will slide further south into the southern plains by Thursday night. Temps may warm slightly, but only to back around normal. The return of slightly warmer temps and moisture will not occur until the high pressure area move into the southeastern US Thur night and Fri. However, along with this will come the chance of pcpn to the area for the end of the week and the weekend. The questions still remain as to the timing of the pcpn return, how warm it will get, and what p-type will occur. Both the GFS and ECMWF continue to not agree on the overall solution with this system. However, there is some agreement as to how the upper level will evolve into Saturday. The upper level low pressure area will weaken and get lifted out into the flow over the weekend. ECMWF is much quicker with this than the GFS. Models also agree that the pcpn will not really begin until Fri night/Sat morning. However, there still remains a chance of pcpn Friday in the southeast, so will keep chance pops there, though would not be surprised to see this change later. Beyond this, models do not agree with location of pcpn and sfc low pressure area. With the ECMWF being quicker with the upper level system, it keeps the low further south and therefore has very little pcpn in our area...and only in the extreme southeast. The GFS is further north with the low, but has shifted it east since yesterday`s model runs. However, it keeps pcpn over the area through the weekend, just not as much as before; and with the low east, temps may not get as warm, thereby effecting the p-type through the weekend. Will still be keeping the p-type simple and just going with snow, becoming rain or snow, then snow at night and rain and/or snow again during the daytime. The chance of pcpn will continue into Sat night. Sunday and Monday will be dry for now as the system should be well east of the area. Temps in the extended will warm, with the warmest temps being on Saturday and then cooling back off by Monday as another shot of colder air slides into the area. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) ISSUED AT 1128 PM CST MON DEC 29 2014 The weak cold front has pretty much dissipated this evening, with just a lingering band of clouds and possibly a few flurries drifting southward across the area. In general, a 2-4 hour period of MVFR clouds could occur over the terminal sites the rest of the night. The base cloud layer appears to be very ragged, and periods of MVFR could be broken up by VFR conditions. Have included flurries only at BMI, with dry conditions elsewhere. No impacts are expected from any snowfall overnight. Mid clouds are indicated in the forecast soundings for the day on Tuesday, with gradual lowering of the mid-deck Tuesday evening down to 10K feet. Breaks in the mid-clouds appears likely based on the amount of dry air above and below the cloud layer. Winds will start out NNE, then shift to the N by sunrise and NW Tuesday afternoon. Wind speeds will generally hover btwn 6-9kt at night and 9-12kt during the day. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Shimon SHORT TERM...Miller LONG TERM...Auten AVIATION...Shimon
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1243 PM EST TUE DEC 30 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 304 AM EST TUE DEC 30 2014 IN THE NEAR TERM PERIOD...THE FOCUS WILL BE ON THE COOL DOWN AS ARCTIC HIGH PRESSURE STRENGTHENS OVER WESTERN CANADA. MUCH COLDER AIR WILL SPILL INTO PORTIONS OF THE CONTINENTAL U.S. AS A RESULT. HOWEVER...NO PRECIPITATION IS EXPECTED UNTIL THE EXTENDED PERIOD WHEN A CUT OFF LOW OVER THE DESERT SOUTHWEST MAKES ITS PROGRESSION ACROSS THE PLAINS...AND INTO CENTRAL INDIANA. TIMING AND TRACKING INCONSISTENCIES ARE MAKING IT DIFFICULT TO PINPOINT PRECIP TYPE AT THIS TIME...BUT EARLY INDICATIONS ARE SHOWING MIXED PRECIPITATION FOR MOST OF FRIDAY AND SATURDAY. PRECIP WILL END FROM WEST TO EAST ON SUNDAY...AND THE REMAINDER OF THE EXTENDED FORECAST WILL BE DRY AS FLOW ALOFT BECOMES MORE ZONAL ON MONDAY. && .NEAR TERM /THIS AFTERNOON/... ISSUED AT 950 AM EST TUE DEC 30 2014 FLURRIES WILL BE REMOVED FROM THE NORTHWEST. EVEN IN CLEAR AIR MODE THE RADARS UPSTREAM DONT SHOW ANYTHING AND THE HRRR DOESNT INTRODUCE ANYTHING. OTHER ELEMENTS OF THE EARLIER FORECAST ARE WORKING WELL BASED ON THE LATEST OBSERVATIONS.&& .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .LONG TERM /FRIDAY THROUGH MONDAY/... ISSUED AT 410 AM EST MON DEC 30 2014 THERE IS BETTER AGREEMENT BETWEEN THE MODELS AS THEY ALL BRING PRECIPITATION NORTH ACROSS OUR ENTIRE REGION FRIDAY NIGHT THROUGH SATURDAY. PREVIOUSLY THE EURO ONLY BROUGHT IT INTO OUR SOUTHERN AREAS...WHILE MOST OTHER MODELS BROUGHT IT FARTHER NORTH. WITH THE EXCEPTION OF THE NAM ALL MODELS HAVE TRENDED A LITTLE SLOWER IN NOT BEGINNING PRECIPITATION UNTIL FRIDAY NIGHT. WILL GO ALONG WITH THIS SCENARIO AND KEEP ALL BUT THE FAR SOUTH DRY UNTIL FRIDAY NIGHT. PRECIPITATION WILL BE THE MAIN ISSUE FRIDAY NIGHT AND SATURDAY AS MODELS PULL WARMER NORTH INTO OUR REGION. BUFKIT SOUNDINGS INDICATE LOW CHANCES OF SNOW ACROSS OUR NORTH AND FREEZING PRECIPITATION SOUTH EARLY FRIDAY NIGHT AND WITH THICKNESS AND TEMPERATURES RISING SLOWLY OVERNIGHT WHICH SHOULD ALLOW CHANCES OF FREEZING RAIN TO SPREAD NORTH BY SATURDAY MORNING AND THEN PRECIPITATION BEING MOSTLY RAIN SATURDAY AFTERNOON. ALL MODELS INDICATE QUITE A BIT OF PRECIPITATION AROUND SATURDAY AND WENT WITH HPC PROGS WHICH INDICATED LIKELY POPS CENTRAL AND SOUTH SATURDAY. AFTER LOW PRESSURE GOES BY...MODELS INDICATE A CHANGEOVER BACK TO LIGHT SNOW OR FLURRIES SATURDAY NIGHT WITH RETURN OF COLDER AIR. WILL ALSO MENTION SLIGHT CHANCE OF SNOW SHOWERS WITH MIXED PRECIP FAR SOUTHEAST SUNDAY MORNING AND THEN DRY AFTER THAT AS COLD HIGH PRESSURE BUILDS BACK IN. MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING AS TEMPERATURES WILL BE NON-DIURNAL. OTHERWISE...MADE ONLY MINOR TWEAKS TO A MOS BLEND ON TEMPERATURES MOST OTHER PERIODS. && .AVIATION /DISCUSSION FOR THE 301800Z TAF ISSUANCE/... ISSUED AT 1233 PM EST TUE DEC 30 2014 MAINLY VFR CONDITIONS EXPECTED THROUGH MOST OF THE TAF PERIOD. THE ONE CAVEAT TO THAT IS THE BAND OF SCT/BKN MVFR CEILINGS EXISTING WITHIN THE 2 OR 3 COUNTY WIDE BAND OF CLOUDS CURRENTLY EXTENDING DOWN FROM NORTH CENTRAL INDIANA THROUGH WEST CENTRAL INDIANA. UNDERNEATH SOME OF THE MORE CONCENTRATED CLOUD SHIELD...BKN TO OVC MVFR CEILINGS ARE PERSISTING. EXPECT THOSE MVFR CEILINGS TO MOVE OUT OF LAF BY 30/20Z AND OUT OF HUF AROUND 30/21Z. DO CURRENTLY EXPECT TO SEE THOSE MVFR CEILINGS MAKE IT INTO IND AROUND 30/18Z AND INTO BMG BY 30/19Z AS CU FIELD IS THICKENING ACROSS WEST- CENTRAL AND CENTRAL PORTIONS OF CENTRAL INDIANA. EXPECT THE MVFR CEILINGS TO SCATTER OR MOVE FROM IND/BMG BY 30/22-23Z. ALONG WITH THE INCREASE IN CLOUDS...A GRADUAL BACKING OF WINDS TO THE NORTHWEST IS EXPECTED AS WELL. WOULD NOT BE SURPRISED TO SEE AN OB OR TWO FROM LAF WITH -SN SENSING FLURRIES WITHIN THE NEXT FEW HOURS AS WELL. OTHERWISE...EXPECT VFR CONDITIONS WITH FEW/SCT CU AND A SCATTERED MID-LEVEL DECK. MODEL SOUNDINGS CONTINUE TO INDICATE CLEARING OCCURRING TONIGHT AS ARCTIC HIGH PRESSURE BUILDS INTO THE GREAT PLAINS STATES. NORTH WINDS AROUND 10 KNOTS WILL BECOME NORTHWEST THIS AFTERNOON AND WEST AROUND 5 TO 7 KNOTS LATE TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...JK SHORT TERM...TDUD LONG TERM...JH AVIATION...MRD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1212 PM EST TUE DEC 30 2014 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 304 AM EST TUE DEC 30 2014 IN THE NEAR TERM PERIOD...THE FOCUS WILL BE ON THE COOL DOWN AS ARCTIC HIGH PRESSURE STRENGTHENS OVER WESTERN CANADA. MUCH COLDER AIR WILL SPILL INTO PORTIONS OF THE CONTINENTAL U.S. AS A RESULT. HOWEVER...NO PRECIPITATION IS EXPECTED UNTIL THE EXTENDED PERIOD WHEN A CUT OFF LOW OVER THE DESERT SOUTHWEST MAKES ITS PROGRESSION ACROSS THE PLAINS...AND INTO CENTRAL INDIANA. TIMING AND TRACKING INCONSISTENCIES ARE MAKING IT DIFFICULT TO PINPOINT PRECIP TYPE AT THIS TIME...BUT EARLY INDICATIONS ARE SHOWING MIXED PRECIPITATION FOR MOST OF FRIDAY AND SATURDAY. PRECIP WILL END FROM WEST TO EAST ON SUNDAY...AND THE REMAINDER OF THE EXTENDED FORECAST WILL BE DRY AS FLOW ALOFT BECOMES MORE ZONAL ON MONDAY. && .NEAR TERM /THIS AFTERNOON/... ISSUED AT 950 AM EST TUE DEC 30 2014 FLURRIES WILL BE REMOVED FROM THE NORTHWEST. EVEN IN CLEAR AIR MODE THE RADARS UPSTREAM DONT SHOW ANYTHING AND THE HRRR DOESNT INTRODUCE ANYTHING. OTHER ELEMENTS OF THE EARLIER FORECAST ARE WORKING WELL BASED ON THE LATEST OBSERVATIONS.&& .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .LONG TERM /FRIDAY THROUGH MONDAY/... ISSUED AT 410 AM EST MON DEC 30 2014 THERE IS BETTER AGREEMENT BETWEEN THE MODELS AS THEY ALL BRING PRECIPITATION NORTH ACROSS OUR ENTIRE REGION FRIDAY NIGHT THROUGH SATURDAY. PREVIOUSLY THE EURO ONLY BROUGHT IT INTO OUR SOUTHERN AREAS...WHILE MOST OTHER MODELS BROUGHT IT FARTHER NORTH. WITH THE EXCEPTION OF THE NAM ALL MODELS HAVE TRENDED A LITTLE SLOWER IN NOT BEGINNING PRECIPITATION UNTIL FRIDAY NIGHT. WILL GO ALONG WITH THIS SCENARIO AND KEEP ALL BUT THE FAR SOUTH DRY UNTIL FRIDAY NIGHT. PRECIPITATION WILL BE THE MAIN ISSUE FRIDAY NIGHT AND SATURDAY AS MODELS PULL WARMER NORTH INTO OUR REGION. BUFKIT SOUNDINGS INDICATE LOW CHANCES OF SNOW ACROSS OUR NORTH AND FREEZING PRECIPITATION SOUTH EARLY FRIDAY NIGHT AND WITH THICKNESS AND TEMPERATURES RISING SLOWLY OVERNIGHT WHICH SHOULD ALLOW CHANCES OF FREEZING RAIN TO SPREAD NORTH BY SATURDAY MORNING AND THEN PRECIPITATION BEING MOSTLY RAIN SATURDAY AFTERNOON. ALL MODELS INDICATE QUITE A BIT OF PRECIPITATION AROUND SATURDAY AND WENT WITH HPC PROGS WHICH INDICATED LIKELY POPS CENTRAL AND SOUTH SATURDAY. AFTER LOW PRESSURE GOES BY...MODELS INDICATE A CHANGEOVER BACK TO LIGHT SNOW OR FLURRIES SATURDAY NIGHT WITH RETURN OF COLDER AIR. WILL ALSO MENTION SLIGHT CHANCE OF SNOW SHOWERS WITH MIXED PRECIP FAR SOUTHEAST SUNDAY MORNING AND THEN DRY AFTER THAT AS COLD HIGH PRESSURE BUILDS BACK IN. MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING AS TEMPERATURES WILL BE NON-DIURNAL. OTHERWISE...MADE ONLY MINOR TWEAKS TO A MOS BLEND ON TEMPERATURES MOST OTHER PERIODS. && .AVIATION /DISCUSSION FOR THE 301800Z TAF ISSUANCE/... ISSUED AT 1147 AM EST TUE DEC 30 2014 MAINLY VFR CONDITIONS EXPECTED THROUGH MOST OF THE TAF PERIOD. THE ONE CAVEAT TO THAT IS THE SPORADIC FEW/SCT MVFR CEILINGS EXISTING WITHIN THE THIN BAND OF CLOUDS CURRENTLY EXTENDING DOWN FROM NORTH CENTRAL INDIANA THROUGH WEST CENTRAL INDIANA. UNDERNEATH SOME OF THE MORE CONCENTRATED CLOUD SHIELD...I.E. ABOVE AND SOUTHWEST OF HUF AND ABOVE AND NORTH OF LAF...BKN TO OVC MVFR CEILINGS ARE PERSISTING. EXPECT THOSE MVFR CEILINGS TO MOVE OUT OF LAF IN THE NEXT 2 HRS OR SO AND OUT OF HUF WITHIN THE NEXT 3 TO 4 HOURS. DO NOT CURRENTLY EXPECT TO SEE THOSE MVFR CEILINGS MAKE IT INTO IND OR BMG. HOWEVER...IT IS NOT OUTSIDE THE REALM OF POSSIBILITY OVER THE NEXT FEW HOURS AS CU FIELD IS THICKENING ACROSS WEST-CENTRAL AND CENTRAL PORTIONS OF CENTRAL INDIANA. ALONG WITH THE INCREASE IN CLOUDS...A GRADUAL BACKING OF WINDS TO THE NORTHWEST IS EXPECTED AS WELL. WOULD NOT BE SURPRISED TO SEE AN OB OR TWO FROM LAF WITH -SN SENSING FLURRIES WITHIN THE NEXT FEW HOURS AS WELL. OTHERWISE...EXPECT VFR CONDITIONS WITH FEW/SCT CU AND A SCATTERED MID-LEVEL DECK. MODEL SOUNDINGS CONTINUE TO INDICATE CLEARING OCCURRING TONIGHT AS ARCTIC HIGH PRESSURE BUILDS INTO THE GREAT PLAINS STATES. NORTH WINDS AROUND 10 KNOTS WILL BECOME NORTHWEST THIS AFTERNOON AND WEST AROUND 5 TO 7 KNOTS LATE TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...JK SHORT TERM...TDUD LONG TERM...JH AVIATION...MRD VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
951 AM EST TUE DEC 30 2014 .UPDATE... THE NEAR TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 304 AM EST TUE DEC 30 2014 IN THE NEAR TERM PERIOD...THE FOCUS WILL BE ON THE COOL DOWN AS ARCTIC HIGH PRESSURE STRENGTHENS OVER WESTERN CANADA. MUCH COLDER AIR WILL SPILL INTO PORTIONS OF THE CONTINENTAL U.S. AS A RESULT. HOWEVER...NO PRECIPITATION IS EXPECTED UNTIL THE EXTENDED PERIOD WHEN A CUT OFF LOW OVER THE DESERT SOUTHWEST MAKES ITS PROGRESSION ACROSS THE PLAINS...AND INTO CENTRAL INDIANA. TIMING AND TRACKING INCONSISTENCIES ARE MAKING IT DIFFICULT TO PINPOINT PRECIP TYPE AT THIS TIME...BUT EARLY INDICATIONS ARE SHOWING MIXED PRECIPITATION FOR MOST OF FRIDAY AND SATURDAY. PRECIP WILL END FROM WEST TO EAST ON SUNDAY...AND THE REMAINDER OF THE EXTENDED FORECAST WILL BE DRY AS FLOW ALOFT BECOMES MORE ZONAL ON MONDAY. && .NEAR TERM /THIS AFTERNOON/... ISSUED AT 950 AM EST TUE DEC 30 2014 FLURRIES WILL BE REMOVED FROM THE NORTHWEST. EVEN IN CLEAR AIR MODE THE RADARS UPSTREAM DONT SHOW ANYTHING AND THE HRRR DOESNT INTRODUCE ANYTHING. OTHER ELEMENTS OF THE EARLIER FORECAST ARE WORKING WELL BASED ON THE LATEST OBSERVATIONS.&& .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... ISSUED AT 304 AM EST TUE DEC 30 2014 THE MAIN FOCUS OF THE SHORT TERM PERIOD CONTINUES TO BE ON TEMPERATURES AND ANY CHANGES IN TIMING OF DAY 5 STORM SYSTEM THAT COULD POSSIBLY RESULT IN PRECIP AS EARLY AS THURSDAY NIGHT. TEMPERATURES WILL REALLY PLUMMET TONIGHT WITH COLD AIR IN PLACE AND PARTLY CLOUDY SKIES. SOME OF THE COLDEST TEMPS IN A LONG TIME WILL AFFECT CENTRAL INDIANA. READINGS IN THE SINGLE DIGITS OVER THE NORTHWESTERN THIRD OF THE FORECAST AREA CAN BE EXPECTED...AND TEENS OVER THE REMAINDER OF CENTRAL INDIANA. THERE WILL BE LITTLE IMPROVEMENT IN TEMPS TOMORROW DESPITE SOME SUNSHINE. HIGHS ARE ONLY EXPECTED TO WARM INTO THE 20S. AS SURFACE FLOW BECOMES SOUTHWESTERLY ON WEDNESDAY NIGHT...TEMPS WILL BECOME SLIGHTLY MORE MILD THOUGH FOR THE SECOND HALF OF THE SHORT TERM PERIOD WITH HIGHS IN THE 30S ON THURSDAY...AND LOWS IN THE 20S ON THURSDAY NIGHT. ATTENTION THEN TURNS TO ANY PRECIP CHANCES AT THE VERY END OF THE SHORT TERM PERIOD AS MOISTURE AHEAD OF DESERT SOUTHWEST CUT OFF LOW MOVES CLOSER TO THE REGION. AS OF NOW...ALL MODELS ARE STILL TRENDING TOWARD A DRY THURSDAY/THURSDAY NIGHT...AND ARE EVEN SLOWING DOWN FURTHER WITH THE BULK OF THE PRECIP PROGGED FOR FRIDAY AND SATURDAY ACROSS CENTRAL INDIANA. && .LONG TERM /FRIDAY THROUGH MONDAY/... ISSUED AT 410 AM EST MON DEC 30 2014 THERE IS BETTER AGREEMENT BETWEEN THE MODELS AS THEY ALL BRING PRECIPITATION NORTH ACROSS OUR ENTIRE REGION FRIDAY NIGHT THROUGH SATURDAY. PREVIOUSLY THE EURO ONLY BROUGHT IT INTO OUR SOUTHERN AREAS...WHILE MOST OTHER MODELS BROUGHT IT FARTHER NORTH. WITH THE EXCEPTION OF THE NAM ALL MODELS HAVE TRENDED A LITTLE SLOWER IN NOT BEGINNING PRECIPITATION UNTIL FRIDAY NIGHT. WILL GO ALONG WITH THIS SCENARIO AND KEEP ALL BUT THE FAR SOUTH DRY UNTIL FRIDAY NIGHT. PRECIPITATION WILL BE THE MAIN ISSUE FRIDAY NIGHT AND SATURDAY AS MODELS PULL WARMER NORTH INTO OUR REGION. BUFKIT SOUNDINGS INDICATE LOW CHANCES OF SNOW ACROSS OUR NORTH AND FREEZING PRECIPITATION SOUTH EARLY FRIDAY NIGHT AND WITH THICKNESS AND TEMPERATURES RISING SLOWLY OVERNIGHT WHICH SHOULD ALLOW CHANCES OF FREEZING RAIN TO SPREAD NORTH BY SATURDAY MORNING AND THEN PRECIPITATION BEING MOSTLY RAIN SATURDAY AFTERNOON. ALL MODELS INDICATE QUITE A BIT OF PRECIPITATION AROUND SATURDAY AND WENT WITH HPC PROGS WHICH INDICATED LIKELY POPS CENTRAL AND SOUTH SATURDAY. AFTER LOW PRESSURE GOES BY...MODELS INDICATE A CHANGEOVER BACK TO LIGHT SNOW OR FLURRIES SATURDAY NIGHT WITH RETURN OF COLDER AIR. WILL ALSO MENTION SLIGHT CHANCE OF SNOW SHOWERS WITH MIXED PRECIP FAR SOUTHEAST SUNDAY MORNING AND THEN DRY AFTER THAT AS COLD HIGH PRESSURE BUILDS BACK IN. MADE SOME ADJUSTMENTS TO HOURLY TEMPERATURES FRIDAY NIGHT AND SATURDAY MORNING AS TEMPERATURES WILL BE NON-DIURNAL. OTHERWISE...MADE ONLY MINOR TWEAKS TO A MOS BLEND ON TEMPERATURES MOST OTHER PERIODS. && .AVIATION /DISCUSSION FOR 301500Z KIND TAF UPDATE/... ISSUED AT 913 AM EST TUE DEC 30 2014 NOT MUCH CHANGE TO PREVIOUS TAF FOR IND. STILL EXPECTING MAINLY VFR THROUGH THE PERIOD. BASED ON CURRENT OBSERVATIONAL TRENDS...DID STRENGTHEN THE WINDS SLIGHTLY OVER THE NEXT COUPLE HOURS AND ALSO DELAYED THE BACKING OF THE SURFACE WINDS. THE PREVIOUS DISCUSSION FOLLOWS... ISSUED AT 625 AM AM EST TUE DEC 30 2014 SATELLITE INDICATES BAND OF STRATO CU WITH DRY SECONDARY COLD FRONT WILL BE MOVING ACROSS TAF SITES TODAY. COULD BE A PERIOD OF MVFR CEILINGS AT KLAF THIS MORNING...OTHERWISE CEILINGS WILL BE JUST ABOVE 3 THOUSAND FEET AS BAND MOVES AS IT MOVES ACROSS. TIMING WILL BE MID MORNING TO MID AFTERNOON AT KLAF AND KHUF AND MAINLY THIS AFTERNOON AT KIND AND KBMG. OTHERWISE...VFR WITH FEW CU AND SCATTERED MID CLOUDS. MODEL SOUNDINGS INDICATE CLEARING SHOULD OCCUR LATE TONIGHT AS ARCTIC HIGH PRESSURE BUILDS INTO THE GREAT PLAINS. NORTH WINDS AROUND 10 KNOTS WILL BECOME NORTHWEST THIS AFTERNOON AND WEST AROUND 5 KNOTS LATE TONIGHT. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...TDUD NEAR TERM...JK SHORT TERM...TDUD LONG TERM...JH AVIATION...MRD/JH VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSINDIANAPOLIS WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS WICHITA KS
310 AM CST TUE DEC 30 2014 .SYNOPSIS... ISSUED AT 308 AM CST TUE DEC 30 2014 LARGE POSITIVE TILTED UPPER TROUGH EXTENDS FROM THE NORTHERN PLAINS INTO NORTHERN CA WITH THE MAIN VORT LOBE OVER THE WESTERN PORTION OF THIS TROUGH. AT THE SURFACE...ARCTIC AIR IS SPILLING SOUTH ACROSS THE PLAINS WITH NEGATIVE TEMP VALUES NOW ENCOMPASSING THE NORTHERN HALF OF NEBRASKA. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 308 AM CST TUE DEC 30 2014 LIGHT SNOW HAS BEEN PERSISTENT OVERNIGHT FOR AREAS ALONG AND WEST OF I-135 AND AM EXPECTING THIS TO CONTINUE THROUGH AT LEAST THE MORNING HOURS AND POSSIBLY INTO THE AFTERNOON. FEEL CONFIDENT IN THIS AS ISENTROPIC LIFT IN THE 280-285K LAYER REMAINS PRETTY MUCH UNCHANGED FROM WHAT IS OCCURRING NOW. EVEN THOUGH MOST SITES WILL NOT TIP OFF A 0.01 OF PRECIP...WILL RUN WITH HIGH POP WORDING AS WHAT IS OCCURRING IS MORE THAN JUST FLURRIES WITH SOME VISIBILITIES AT OR LESS THAN 3SM. WILL KEEP WITH CURRENT HEADLINE MAINLY DUE TO COMING CLOSE TO WIND CHILL CRITERIA. THE FRIGID AIRMASS WILL REMAIN IN PLACE TONIGHT THROUGH WED WITH TEMPS AROUND 20 DEGREES BELOW NORMAL. WOULD NOT BE SHOCKED IF WE GET SOME FLURRIES TO LINGER TONIGHT OVER THE SOUTHWEST PORTION OF THE FORECAST AREA AS THE LIFT IS SLOW TO MOVE OUT. THE MAIN VORT LOBE OUT WEST IS EXPECTED TO CUT OFF AND TRACK ACROSS THE DESERT SOUTHWEST BY THU AND WILL BECOME THE FOCUS FOR THE EXTENDED PERIODS. .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 308 AM CST TUE DEC 30 2014 THROUGH 00Z SAT BOTH THE ECMWF AND GFS REMAIN FAIRLY SIMILAR IN TRACKING THE CLOSED LOW OVER EASTERN NM. HOWEVER...THESE MODELS AGAIN START TO DEVIATE FOR THE FRI NIGHT THROUGH SAT TIME FRAME. THE GFS IS CONTINUING THE TREND OF LIFTING THE IMPULSE FURTHER NORTH COMPARED TO THE ECMWF. THE GFS SOLUTION WOULD RESULT IN WIDESPREAD WINTRY PRECIP FOR MOST OF THE FORECAST AREA FRI NIGHT INTO SAT MORNING WITH THE ECMWF KEEPING MOST OF THE PRECIP SOUTH OF THE KS/OK BORDER. HAVE A SLIGHT LEAN TO THE GFS SINCE IT HAS BEEN A BIT MORE CONSISTENT AND FEEL THAT AT LEAST A PORTION OF OUR FORECAST AREA WILL BE IMPACTED BY WINTRY PRECIP OVER THE WEEKEND. LAWSON && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1135 PM CST MON DEC 29 2014 LIGHT SNOW IS MOVING ACROSS THE WESTERN SECTIONS OF THE FORECAST AREA IMPACTING KRSL/KHUT/KICT AND WILL SOON IMPACT KSLN. MVFR TO IFR CEILINGS AND VISIBILITIES ARE ALSO IMPACTING THE TERMINALS. EXPECT THIS TO PERSIST THROUGH THE OVERNIGHT HOURS. THE SHORT- TERM HIGHER RES RUC GUIDANCE SHOWS THE SNOW DIMINISHING AROUND SUNRISE...WHILE THE NAM KEEPS PRECIP AROUND LONGER. HAVE TRENDED TOWARD THE RUC AT THIS TIME IN THE TAFS ENDING THE SNOW AROUND SUNRISE AND EVENTUALLY LIFTING THE CEILINGS TO HIGH END MVFR AND IN SOME CASES VFR BY THE END OF THE PERIOD. NORTH TO NORTHEASTERLY WINDS WILL PERSIST THROUGH THE FORECAST. BILLINGS WRIGHT && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 18 4 22 14 / 30 10 0 0 HUTCHINSON 13 2 21 13 / 40 10 0 0 NEWTON 15 2 21 13 / 20 10 0 0 ELDORADO 18 4 22 14 / 20 10 0 0 WINFIELD-KWLD 21 6 24 16 / 20 10 0 0 RUSSELL 7 -3 15 8 / 30 10 0 0 GREAT BEND 8 -2 17 10 / 30 10 0 0 SALINA 12 -1 18 12 / 30 10 0 0 MCPHERSON 12 1 20 12 / 30 10 0 0 COFFEYVILLE 30 9 27 16 / 10 10 0 0 CHANUTE 25 5 24 15 / 10 10 0 0 IOLA 23 4 24 15 / 10 10 0 0 PARSONS-KPPF 27 7 25 16 / 10 10 0 0 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR KSZ032-033-047- 048. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1135 PM CST MON DEC 29 2014 ...UPDATED FOR 06Z AVIATION DISCUSSION... .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 234 PM CST MON DEC 29 2014 ARCTIC AIR OVER THE DAKOTAS/NEBRASKA WAS CONTINUING TO SURGE SOUTH AND WILL SPREAD ACROSS KANSAS FOR TONIGHT AND REMAIN OVER THE AREA FOR THE NEXT COUPLE OF DAYS. MEANWHILE SNOW CURRENTLY OVER NORTHWEST KANSAS WILL EXPAND EASTWARD INTO CENTRAL KANSAS FOR TONIGHT WITH SOME LIGHT ACCUMULATIONS POSSIBLE...WITH A TRACE TO 2 INCHES POSSIBLE. THE SNOW SHOULD BEGIN TO TAPER OFF QUICKLY FOR TUESDAY MORNING...AS THE VERTICAL MOTION FROM UPPER LEVEL WAVE DIMINISHES. WIND CHILLS WILL DROP TO DANGEROUS LEVELS FOR TUESDAY MORNING AND COULD AGAIN FOR WEDNESDAY MORNING ACROSS CENTRAL KANSAS. A WIND CHILL ADVISORY COULD BE HOISTED BY LATER SHIFTS FOR WEDNESDAY MORNING IF TRENDS MAINTAIN. TEMPERATURES SHOULD MODIFY AND WARM A BIT COME THURSDAY AS DOWNSLOPE FLOW HELPS BOOSTS DAYTIME HIGHS. .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 234 PM CST MON DEC 29 2014 SOME UNCERTAINTY REMAINS BETWEEN THE GFS/ECMWF MODEL AS EXPECTED THIS FAR OUT IN TIME WITH POSITIONING OF THE FRI/SAT SYSTEM...BUT NONE THE LESS WINTER PRECIPITATION STILL SEEMS REASONABLE FOR MAINLY SOUTH CENTRAL/SOUTHEAST KANSAS. BELOW NORMAL TEMPERATURES WILL CONTINUE FOR SUNDAY AND MONDAY AS SURFACE HIGH PRESSURE BUILDS OVER KANSAS...AND TEMPERATURES COULD BE EVEN COLDER IF FRESH SNOW FALLS ACROSS THE REGION. JAKUB && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1135 PM CST MON DEC 29 2014 LIGHT SNOW IS MOVING ACROSS THE WESTERN SECTIONS OF THE FORECAST AREA IMPACTING KRSL/KHUT/KICT AND WILL SOON IMPACT KSLN. MVFR TO IFR CEILINGS AND VISIBILITIES ARE ALSO IMPACTING THE TERMINALS. EXPECT THIS TO PERSIST THROUGH THE OVERNIGHT HOURS. THE SHORT- TERM HIGHER RES RUC GUIDANCE SHOWS THE SNOW DIMINISHING AROUND SUNRISE...WHILE THE NAM KEEPS PRECIP AROUND LONGER. HAVE TRENDED TOWARD THE RUC AT THIS TIME IN THE TAFS ENDING THE SNOW AROUND SUNRISE AND EVENTUALLY LIFTING THE CEILINGS TO HIGH END MVFR AND IN SOME CASES VFR BY THE END OF THE PERIOD. NORTH TO NORTHEASTERLY WINDS WILL PERSIST THROUGH THE FORECAST. BILLINGS WRIGHT && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 15 19 4 21 / 60 10 10 0 HUTCHINSON 10 15 2 20 / 100 20 10 0 NEWTON 11 17 2 20 / 50 10 10 0 ELDORADO 14 20 4 22 / 30 10 10 0 WINFIELD-KWLD 18 22 6 23 / 30 10 10 0 RUSSELL 4 9 -3 18 / 100 30 10 0 GREAT BEND 6 10 -2 18 / 100 30 10 0 SALINA 8 12 -1 19 / 90 10 10 0 MCPHERSON 9 14 1 20 / 100 10 10 0 COFFEYVILLE 23 28 9 25 / 30 10 10 0 CHANUTE 19 24 5 23 / 10 10 10 0 IOLA 18 23 4 22 / 10 10 10 0 PARSONS-KPPF 21 26 7 24 / 20 10 10 0 && .ICT WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON CST TUESDAY FOR KSZ032-033- 047-048. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
637 PM EST WED DEC 31 2014 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 429 PM EST WED DEC 31 2014 WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW FROM NW CANADA INTO THE GREAT LAKES BETWEEN A TROUGH OVER HUDSON BAY AND A RIDGE FROM THE ERN PACIFIC INTO BC. A SHORTWAVE TROUGH WAS MOVING THROUGH UPPER MI WITH ANOTHER WEAKER SHRTWV UPSTREAM OVER MANITOBA. ANOTHER CLIPPER SHRTWV WAS FARTHER UPSTREAM OVER NW SASK. AT THE SFC...STRONG WEST WINDS PREVAILED ACROSS THE REGION BETWEEN A 988 MB LOW NEAR HUDSON BAY AND 1036 MB ARCTIC HIGH PRES INTO THE SRN PLAINS. THE STRONGEST WINDS THIS MORNING INTO EARLY AFTERNOON ACROSS LAKE SUPERIOR OCCURRED AS THE STRONGER PRES FALLS SLID THROUGH NRN ONTARIO. WITH 850 MB TEMPS AROUND -19C AND CONVERGENT WRLY FLOW DEVELOPING LES HAS INCREASED ACROSS THE KEWEENAW AS WINDS VEERED FROM SW TO W. TONIGHT...EXPECT THE STRONGEST LOW LEVEL CONV SUPPORTING LES TO REMAIN OVER THE KEWEENAW. EVEN WITH A FAVORABLE POSITION OF THE DGZ IN THE CLOUD LAYER...THE STRONGER WINDS WILL CREATE ENOUGH COMPACTION/FRACTURING TO LIMIT SLR VALUES CLOSER TO 20/1. SO OVERALL ACCUMULATIONS TONIGHT IN THE 2 TO 5 INCH RANGE ARE EXPECTED. WINDS GUSTING INTO THE 30 TO 40 MPH RANGE WILL ALSO CONTINUE TO PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW IN OPEN AREAS WHERE OCNL WHITEOUT CONDITIONS ARE POSSIBLE. WINDS ARE EXPECTED TO DIMINISH OVERNIGHT REDUCING THE BLSN HAZARDS. THU...THE NRN SASK SHRTWV TROUGH WILL BRUSH THE AREA WITH ENOUGH 700-500 MB QVECTOR CONV AND 800-600 MB FGEN TO SUPPORT AN AREA OF LIGHT SNOW FROM NRN MN INTO NRN WI AND UPPER MI. WITH THE LACK OF SIGNFICANT MOISTURE INFLOW/AVAILABILITY...SNOW AMOUNTS OF A HALF INCH OR LESS ARE EXPECTED. HOWEVER...THE DEEPER MOISTURE WITH INCREASING INVERSION HEIGHTS INTO THE AREA WILL SUPPORT GREATER LES INTENSITY FOR THE W TO WNW FLOW LES SNOW BELTS. SINCE THE STRONGER LOW LEVEL CONV IS EXPECTED TO SHIFT SOUTHWARD OVERALL SNOW AMOUNTS SHOULD REMAIN IN THE 1 TO 3 INCH RANGE. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 316 PM EST WED DEC 31 2014 AN UPPER TROUGH OVER EASTERN CANADA LEAD TO COLD AIR AND LAKE EFFECT SNOW OVER THE NORTHWEST WIND SNOW BELTS TO START THE PERIOD. THIS LIGHT TO OCCASIONALLY MODERATE LAKE EFFECT SNOW WILL CONTINUE IN THOSE NORTHWEST WIND BELTS ON THURSDAY NIGHT...BUT AS THE LOW LEVEL WINDS BACK LATE THURSDAY NIGHT INTO FRIDAY MORNING...WILL FOCUS THE POPS/SNOW TO THE WEST-NORTHWEST AREAS ON FRIDAY (AND WESTERLY AREAS LATE FRIDAY AFTERNOON). WHILE LAKE INDUCED EQUILIBRIUM LEVELS WILL BE AROUND 8KFT...THERE ARE SOME CONCERNS IN THE AMOUNT OF MOISTURE AVAILABLE AS SUBSIDENCE AND DRIER AIR ARRIVE THURSDAY NIGHT FROM A HIGH MOVING SOUTHEAST INTO MINNESOTA. THUS...WILL STICK WITH A DUSTING TO 3-4IN EVERY 12HRS THROUGH FRIDAY...WITH THE HIGHEST AMOUNTS OVER THE EAST WITH THE LONGER FETCH AND SOME INDICATIONS OF A LINGERING TROUGH AIDING CONVERGENCE TOWARDS WHITEFISH POINT. THE HIGH WILL SHIFT SOUTHEAST OF THE AREA ON FRIDAY EVENING...BACKING WINDS TO THE SOUTHWEST AND ONLY LEAVING LAKE EFFECT SNOW OVER THE KEWEENAW FOR FRIDAY NIGHT. THE FOCUS THEN TURNS TO THE INTERACTION AND PHASING OF THE SPLIT FLOW FOR THE START OF THE WEEKEND. MODELS SEEM TO COMING INTO BETTER AGREEMENT ON THE OVERALL IDEA FOR THE WEEKEND...ALTHOUGH THERE ARE STILL SMALLER DIFFERENCES THAT COULD HAVE AN IMPACT ON THE AMOUNT OF SNOW SEEN OVER PARTS OF THE U.P. THERE ARE TWO FEATURES AT PLAY FOR THIS WEEKEND...THE FIRST IS THE REMNANTS OF THE UPPER LOW PRODUCING SNOW OVER THE SOUTHWEST CONUS TODAY AND THE SECOND FEATURE IS A SHORTWAVE CURRENTLY OVER THE ALEUTIANS ISLANDS AND DROPPING SOUTHEAST INTO THE NORTHERN ROCKIES ON FRIDAY NIGHT. THIS WILL LEAD TO A LOW DEVELOPING IN THE LEE OF THE NORTHERN ROCKIES AND THEN MOVING EAST INTO THE DAKOTAS AND WESTERN MINNESOTA BY SATURDAY MORNING. EXPECT SNOW TO SPREAD EAST AHEAD OF THIS LOW AND INTO THE NORTHWEST HALF OF THE CWA...ASSOCIATED WITH STRONG MID LEVEL WARM AIR ADVECTION. WHILE THE HEAVIEST SNOW APPEARS TO OCCUR OVER LAKE SUPERIOR...WILL SHOW SOME LIKELY POPS OVER AND AROUND THE KEWEENAW PENINSULA FOR SATURDAY. AS THAT IS OCCURRING...THE NORTHERN SHORTWAVE WILL CONTINUE TO DIVE SOUTHEAST AND PHASE WITH THE SOUTHERN UPPER LOW AND LEAD TO BOTH EJECTING NORTHEAST THROUGH THE LOWER GREAT LAKES REGION SATURDAY NIGHT INTO SUNDAY. AS EXPECTED IN THESE PHASING EVENTS...EACH MODEL RUN GIVES A SLIGHTLY DIFFERENT IDEA ON THE EVOLUTION OF THE PHASED FEATURES AND IN TURN THE SURFACE FEATURES. OVERALL...THE GENERAL IDEA IS FOR A STRENGTHENING LOW TO LIFT NORTHEAST THROUGH SOUTHEAST LOWER MICHIGAN ON SATURDAY NIGHT AND THEN INTO QUEBEC ON SUNDAY. WITH THAT TRACK...WOULD EXPECT MUCH OF THE SYNOPTIC FORCING/PRECIPITATION ASSOCIATED WITH THOSE FEATURES TO MISS THE U.P....BUT WOULD STILL EXPECT AT LEAST SOME LAKE ENHANCEMENT AS THE WINDS TURN TO THE NORTHWEST BEHIND THE ELONGATED SURFACE TROUGH STRETCHING NORTH OVER EASTERN LAKE SUPERIOR LATE SATURDAY NIGHT. INITIALLY...WOULDN/T EXPECT THE LAKE ENHANCEMENT TO AMOUNT TO TOO HIGH OF SNOWFALL AMOUNTS ON SATURDAY NIGHT...BUT AS MUCH COLDER AIR MOVES INTO THE AREA (850MB TEMPS FALLING TO -25C BY 00Z MONDAY) AND THE DEEPER MOISTURE IS STILL PRESENT FROM THE DEPARTING SYSTEM...WOULD EXPECT THE LAKE ENHANCEMENT/EFFECT SNOW TO TAKE OFF ON SUNDAY IN THE NORTHWEST WIND SNOW BELTS. WILL TREND POPS UP TO DEFINITE VALUES DURING THIS PERIOD AND CONTINUE TO MENTION MODERATE/HEAVY SNOW WORDING IN THE HWO. BEHIND THE LOW...EXPECT THE FIRST PART OF THE WORK WEEK TO BE VERY COLD WITH CONTINUED LAKE EFFECT SNOW. THE CANADIAN UPPER TROUGH WILL SAG SOUTH INTO THE GREAT LAKES REGION AND KEEP THE COLD AIR IN PLACE (850MB TEMPS IN THE LOW 20C BELOW ZERO)...WITH ANOTHER SHORTWAVE MOVING THROUGH ON MONDAY NIGHT POTENTIALLY PULLING 850MB TEMPERATURES CLOSE TO -30C FOR TUESDAY. THAT WILL LEAD TO VERY COLD HIGH TEMPERATURES FOR MONDAY/TUESDAY...WITH SOME LOCATIONS OVER THE INTERIOR WEST EVEN STRUGGLING TO RISE ABOVE 0. IN FACT...LOOKING AT THE 00Z ECMWF ENSEMBLE MEMBERS AT KSAW AND OTHER SITES IN THE WESTERN/CENTRAL U.P....THERE MAY END UP BEING A 24-36 HOUR PERIOD OF SUB ZERO TEMPERATURES LATE SUNDAY NIGHT THROUGH AT LEAST TUESDAY MORNING. THE COMBINATION OF THE COLD TEMPERATURES AT NIGHT (SINGLE DIGITS AND TEENS BELOW ZERO) AND WINDS IN THE 5-10MPH RANGE WILL LEAD TO LOW WIND CHILL VALUES MONDAY/TUESDAY MORNINGS AND POTENTIALLY EVENING WEDNESDAY MORNING. AS LONG AS THE WIND SPEEDS STAY UP...WOULD EXPECT THE NEED FOR WIND CHILL ADVISORIES AT A MINIMUM AND WILL CONTINUE TO ADDRESS IN THE HWO. AS FOR LAKE EFFECT DURING THE FIRST PART OF NEXT WEEK...EXPECT WINDS TO BACK TO THE WEST ON MONDAY AND WILL FOCUS THE LAKE EFFECT POPS IN THOSE AREAS. WITH THE AMOUNT OF COLD AIR IN PLACE...VERY LITTLE OF THE CLOUD LAYER WILL BE IN THE DGZ AND MOST WILL BE ABOVE IT...WHICH LEADS TO MORE COLUMN/PLATE SNOWFLAKES AND WOULD EXPECT ACCUMULATIONS TO BE LIMITED. WINDS WILL SHIFT MORE TO THE NORTHWEST ON TUESDAY BEHIND THAT NEXT SHORTWAVE AND WILL TREND POPS TO THAT FAVORED WIND DIRECTION. WITH THE AMOUNT OF COLD AIR...THERE SHOULDN/T BE MUCH OF AN ISSUE FOR AT LEAST SOME LAKE EFFECT...SO DID TREND POPS UP TO LIKELY-DEFINITE VALUES EVEN THOUGH AMOUNTS SHOULD BE LIMITED. AS THE UPPER TROUGH SHIFTS EAST ON WEDNESDAY AND THROUGH THE END OF THE WORK WEEK...THE UPPER GREAT LAKES REGION SHOULD SEE A MODERATION IN THEIR TEMPERATURES TOWARDS MORE NORMAL VALUES TOWARDS THE END OF NEXT WEEK. LOOKING AT THE 00Z ECMWF ENSEMBLE MEAN FOR DAYS 9-15...IT SHOWS MORE OF A ZONAL FLOW ACROSS THE CONUS...WHICH WOULD TRANSLATE TO MORE NORMAL OR EVEN SLIGHTLY ABOVE NORMAL TEMPERATURES HEADING INTO THE MIDDLE OF JANUARY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING) ISSUED AT 637 PM EST WED DEC 31 2014 GUSTY WINDS OVER THE KEWEENAW TO KEEP BLSN GOING INTO THE EVENING HOURS AND COMBINED WITH LES WILL KEEP VISIBILITY IN THE IFR RANGE AT KCMX...ALTHOUGH THERE MAY BE A FEW PERIODS WHERE VSBYS RISE INTO THE LOW MVFR RANGE AS SLIGHTLY DRIER AIR WORKS INTO THE AREA. ONCE WINDS SHIFT MORE TO THE WEST...IFR CONDITIONS WILL PREVAIL AT KCMX THROUGH THE NIGHT AND INTO THE EARLY DAYLIGHT HOURS. VFR/MVFR CONDITIONS TO HOLD AT KIWD. VFR CONDITIONS TO CONTINUE AT KSAW WITH SW TO W DOWNSLOPING FLOW TO PERSIST. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 429 PM EST WED DEC 31 2014 LAKE SUPERIOR WILL BE STUCK BETWEEN VERY STRONG HIGH PRESSURE ACROSS THE S PLAINS AND A DEEP HUDSON BAY LOW TODAY. GALES OF 35-45KTS WILL CONTINUE BEFORE SLOWLY DIMINISHING TO 35KTS LATE TONIGHT INTO THURSDAY MORNING OUT OF THE W-NW. GIVEN PLENTY OF COLD AIR...AND STRONG WINDS...HEAVY FREEZING SPRAY WILL ALSO BE A CONCERN INTO THURSDAY. LOOK FOR THE TROUGH OVER LAKE SUPERIOR TO DEEPEN TONIGHT THROUGH THURSDAY. THE HUDSON BAY LOW WILL SHIFT AND WEAKEN ACROSS N QUEBEC THURSDAY NIGHT...ALLOWING THE TROUGH ACROSS LAKE SUPERIOR TO WEAKEN AS WELL. HIGH PRESSURE SINKING ACROSS MANITOBA AND MINNESOTA THURSDAY NIGHT WILL BUILD RIDGE ACROSS LAKE SUPERIOR ON FRIDAY AS IT PROGRESSES ACROSS THE REMAINDER OF THE GREAT LAKES. A WEAK TROUGH WILL LIKELY LINGER ACROSS MAINLY E LAKE SUPERIOR DURING THIS TIME. EXPECT A LOW NEAR MONTANA ON FRIDAY TO TRACK ACROSS THE N AND CENTRAL PLAINS SATURDAY MORNING...AND THE MID MISSISSIPPI VALLEY SATURDAY AFTERNOON...BEFORE DEEPENING NORTHEASTWARD ACROSS THE LOWER GREAT LAKES AND QUEBEC LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING A TROUGH THROUGH THE AREA SATURDAY NIGHT INTO SUNDAY...ALONG WITH THE POTENTIAL FOR N-NW GALES. HEAVY FREEZING SPRAY WILL ALSO MAKE A RETURN ACROSS MUCH OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THURSDAY FOR MIZ001-003. LAKESHORE FLOOD ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ001- 003. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST /3 AM CST/ THURSDAY FOR LSZ162-240>245-248>251-263>267. GALE WARNING UNTIL 10 AM EST THURSDAY FOR LSZ266-267. GALE WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162- 241>248-263>265. HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST THURSDAY FOR LSZ246- 247. GALE WARNING UNTIL 7 AM EST THURSDAY FOR LSZ249>251. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST THURSDAY FOR LMZ221- 248-250. GALE WARNING UNTIL 1 AM EST THURSDAY FOR LMZ221-250. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...RJT MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
559 PM EST TUE DEC 30 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 427 PM EST TUE DEC 30 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT MID/UPPER LEVEL RIDGE FROM THE ERN PACIFIC INTO BC AND A TROUGH OVER NE CANADA RESULTING IN NNW FLOW TOWARD NRN ONTARIO AND THE NRN LAKES. A SHORTWAVE TROUGH AXIS EXTENDED FROM JAMES BAY INTO SE NORTH DAKOTA. WITH ONLY WEAK FORCING AND LITTLE MOISTURE AVAILABLE...NO PCPN WAS ASSOCIATED WITH THIS FEATURE. FURTHER UPSTREAM...A STRONGER SHRTWV WAS MOVING THROUGH NRN SASK/MANITOBA. AT THE SFC...W TO WNW FLOW PREVAILED ACROSS UPPER MI AND LAKE SUPERIOR AS 1048 MB HIGH PRES CONTINUES TO SINK THROUGH THE NRN AND CNTRL PLAINS. EVEN WITH 850 MB TEMPS NEAR -23C...SATELLITE/RADAR INDICATED ONLY LIGHT TO MODERATE LES INTO NW UPPER MI AND EAST OF MUNISING AS INVERSION HEIGHTS REMAINED NEAR 4K FT WITH VERY DRY AIR UPSTREAM. TONIGHT...EXPECT WINDS TO GRADUALLY BACK TO SW AHEAD OF THE SASK/MANITOBA SHRTWV WHICH WILL PUSH THE LES MOSTLY OFFSHORE. HOWEVER...ADDITIONAL SNOWFALL AMOUNTS OF 1 TO 3 INCHES NW(KEWEENAW AND 2 TO 4 INCHES NE (NE OF P53) ARE POSSIBLE. TEMPS FALLING OFF INTO THE -7F TO -12F RANGE AND WINDS NEAR 10 MPH WILL DROP WIND CHILLS INTO THE -20 TO -33 RANGE OVER THE INTERIOR WRN HALF WHERE WIND CHILL ADVISORIES WILL REMAIN IN EFFECT. WEDNESDAY...AS THE SHRTWV MOVES THROUGH THE NRN LAKES AND DRAGS A WEAK TROUGH THE AREA...WINDS WILL VEER AGAIN FROM SW TO W BY AFTERNOON. THIS WILL BRING THE LES INTO THE NRN KEWEENAW BY MIDDAY AND INTO MUCH OF THE REST OF THE PENINSULA BY MID TO LATE AFTERNOON. THE COMBINATION OF THE LES AND WIND GUSTS OVER 40 MPH WILL LEAD TO VERY POOR VSBY WHICH WILL LINGER INTO THE EVENING...PROMPTING THE ISSUANCE OF AN LES ADVY. ALTHOUGH THERE WILL BE A PERIOD OF DEEPER MOISTURE THAT SHOULD INTENSIFY LES...THE SHIFTING WIND DIRECTIONS SHOULD LIMIT OVERALL AMOUNTS TO THE 1 TO 3 INCH RANGE BY EVENING. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 427 PM EST TUE DEC 30 2014 UPPER AIR PATTERN STARTS OUT WITH TROUGHING ANCHORED OVER HUDSON BAY AND ANOTHER MORE COMPACT TROUGH OVER DESERT SOUTHWEST OF CONUS. ONLY RIDGING OF NOTE IS OVER THE EASTERN PACIFIC OCEAN INTO FAR WESTERN CANADA. ATTENTION THIS WEEKEND WILL BE ON THE SOUTHWEST CONUS TROUGH. MODELS CONTINUE TO FAVOR IDEA THAT AS STRONG JET ENERGY ADVANCES AHEAD OF TROUGH...IT WILL EMERGE OVER THE SOUTHERN PLAINS ON SATURDAY AND LIFT OVER THE GREAT LAKES ON SUNDAY. MEANWHILE...ANOTHER SHORTWAVE WITHIN THE BASE OF LARGER TROUGHING OVER EASTERN CANADA WILL WORK OVER THE UPPER GREAT LAKES. ONE OR BOTH OF THESE FEATURES MAY BRING WIDESPREAD SNOW TO UPR MICHIGAN FRIDAY NIGHT THROUGH SATURDAY NIGHT. THERE IS POTENTIAL THAT THE TWO FEATURES COULD PHASE...THOUGH THAT IS NOT CERTAIN...AND THAT WOULD RESULT IN GREATEST CHANCE OF SEEING HIGHER END SNOW EVENT. NO MATTER HOW IT SHAKES OUT...THERE ARE INDICATIONS VERY CHILLY AIRMASS...EVEN COLDER THAN ONE CURRENTLY AFFECTING THE REGION...WILL SETTLE OVER UPR GREAT LAKES BY EARLY NEXT WEEK. BEYOND END OF EXTENDED THERE ARE SIGNALS THAT RIDGE OVER EAST PACIFIC BREAKS DOWN AND MORE MILD AIR RETURNS TO MUCH OF THE CONUS. PATTERN SHIFT THE CFSV2 HAS BEEN SHOWING FOR A WHILE NOW. THUS...OVERALL IT DOES NOT APPEAR THAT THE UPCOMING COLD WILL BE THAT LONG LASTING. INTIALLY THE MAIN ISSUE WILL BE THE ONGOING WEST FLOW LAKE EFFECT AND BLOWING SNOW WITH POOR VSBY OVER THE KEWEENAW. DECENT AGREEMENT THAT SHORTWAVE DROPPING WNW-ESE OVER LK SUPERIOR AND UPR MICHIGAN WEDNESDAY EVENING WITH LEADING SFC TROUGH AND ENHANCED CONVERGENCE AND ADDITIONAL MOISTURE WILL RESULT IN A A BRIEF PERIOD OF MODERATE TO HEAVY LES. WIND CORE MAX AT 950-925MB OVER 40 KTS WILL BE EASING BY WEDNESDAY EVENING...BUT MIXED LAYER WINDS UP TO 40 KTS WILL STILL RESULT IN STRONG/GUSTY WINDS OVER 30 MPH AND BLSN/POOR VSBY. SOUNDINGS SHOW MARGINAL MOISTURE AND INSTABILITY FOR SIGNIFICANT LES THOUGH AFTER THE TROUGH PASSAGE WITH INVERSIONS PEAKING AT 5-7 KFT AGL WEDNESDAY EVENING AND LAKE INDUCED EQL NOT MUCH HIGHER THAN THAT. MAJORITY OF THE MOIST LAYER IS WITHIN THE DGZ BUT STRONG WINDS WILL LIKELY CUT DOWN SLR/S. POOR VSBY WILL BE THE BIGGER STORY COMPARED TO SNOW AMOUNTS. AFTER COORDINATING WITH SHORT TERM FORECASTER... DECIDED TO GO WITH LAKE EFFECT SNOW ADVISORY FOR SNOW AND BLOWING SNOW WEDNESDAY AFTN THROUGH EARLY AFTERNOON ON NEW YEARS DAY. WILL MENTION OCCASIONAL WHITEOUT CONDITIONS IN THE WSW STATEMENT. LAKE EFFECT AND BLOWING SNOW BECOME FACTOR LATE WEDNESDAY NIGHT INTO THURSDAY FOR AREAS FAVORED BY WNW WINDS...ONTONAGON COUNTY OVER THE WEST AND IN THE SNOW BELTS OF EASTERN HALF OF UPR MICHIGAN. LOOKING AT ONLY A PURE LES SETUP AS SOUNDINGS SHOW SHARP DRYING ABOVE 8KFT. TEMPS AT TOP OF INVERSION BLO -20C LEAD TO MARGINAL INSTABILITY GIVEN WATER TEMPS 2-3C. MOST OF LAKE CONVECTIVE LAYER WILL BE IN THE DGZ AND WINDS WILL BE DIMINISHING...SO FLUFF FACTOR WILL PLAY MORE OF A ROLE. OVERALL...ADVY SNOW AMOUNTS SEEM POSSIBLE INTO NEW YEARS DAY FOR THE WNW FLOW AREAS. LAKE EFFECT LINGERS FOR WNW FLOW AREAS INTO FRIDAY...BUT WILL CONTINUE TO DIMINISH AS HIGH PRESSURE RIDGE SLIDES ACROSS WESTERN GREAT LAKES. COLD WILL SLOWLY EASE...THOUGH TEMPS WELL BLO ZERO EXPECTED THURSDAY NIGHT OVER INTERIOR CNTRL UPR MICHIGAN. INCREASE OF MID CLOUDS MAY RESULT IN LESS TEMP DROP OVER WEST CWA. MAIN QUESTION THIS WEEKEND IS HOW MUCH PHASING OCCURS BTWN APPROACHING NORTHERN STREAM SHORTWAVE TROUGH AND THE UPPER LOW OPENING UP AS IT LIFTS INTO THE CNTRL PLAINS FM THE SOUTHWEST CONUS. SINCE MAJORITY OF JET ENERGY REMAINS AHEAD OF THE SOUTHERN STREAM TROUGH...WOULD EXPECT IT TO STAY FAIRLY PROGRESSIVE AND HAVE LESS CHANCE OF PHASING WITH NORTHERN STREAM SYSTEM. EVEN SO...THE NORTHERN STREAM SHORTWAVE ALONG WITH INCREASING NNE-NNW FLOW WITH H85 TEMPS BLO -12C SATURDAY NIGHT INTO SUNDAY MAY LEAD TO SEVERAL INCHES OF SNOW. BEST SHOT OF SYNOPTIC SNOW WOULD BE OVER THE SOUTH AND EAST CWA WHILE THE GREATEST CHANCE FOR LAKE ENHANCEMENT WOULD BE OVER THE WEST AND NORTH CENTRAL CWA. TIGHT PRESSURE GRADIENT RESULTS IN GUSTY WINDS AND BLOWING SNOW AS WELL. MODEL TRENDS FOR THIS SYSTEM ARE VARIABLE WITH EARLIER RUNS A FEW DAYS AGO SHOWING A WRAPPED UP SYSTEM AND RECENT RUNS BACKING AWAY FM THAT. LATEST RUNS SEEM TO BE TRYING TO COME BACK TO AT LEAST A FARTHER WEST TRACK TO THE SOUTHERN STREAM SYSTEM IF NOT A MORE PHASED SYSTEM. SYSTEM BEARS WATCHING AS IT COULD RESULT IN SOME HEADLINES. BEHIND THE SYSTEM...LOOKS VERY COLD WITH H85 TEMPS DOWN TO -28C BY NEXT MONDAY. INCREASED POPS FOR LAKE EFFECT IN WNW-W FLOW AREAS. MAJORITY OF LAKE CONVECTIVE LAYER IS AT TEMPS BLO -20C...SO SLR/S WILL BE LOW AND MAIN PROBLEM COULD BE POOR VSBY. COULD ALSO HAVE WIND CHILL ISSUES FOR THE FIRST DAY BACK TO SCHOOL AFTER WINTER VACATION. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING) ISSUED AT 559 PM EST TUE DEC 30 2014 LAKE EFFECT SNOW WILL FAVOR PERSISTENT MVFR CIGS AND IFR/LIFR VSBY AT CMX THROUGH THE PERIOD. GUSTY WINDS INTO WED MORNING WILL ALSO REDUCE VSBY WITH BLSN. LAKE EFFECT CLOUDS/SNOW WILL LIFT FAR ENOUGH TO THE NORTH FOR IMPROVING CONDITIONS TO VFR WHICH WILL LAST INTO WED AS WINDS BECOME WSW AT IWD. AT SAW...VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD. WILL GET GUSTY AT ALL SITES LATE TONIGHT THROUGH WED. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 427 PM EST TUE DEC 30 2014 WEST TO SOUTHWEST GALES 40-45 KTS ARE EXPECTED OVER MOST OF LK SUPERIOR BEGINNING LATER TONIGHT WILL SHIFT TO WEST-NORTHWEST GALES TO 35 KTS LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. IN ADDITION TO THE GALES... HEAVY FREEZING SPRAY WILL AFFECT MOST OF THE LAKE INTO THURSDAY. WINDS DIMINISH TO LESS THAN 25 KTS BY FRIDAY...BUT THE LULL WILL BE BRIEF AS NORTHERLY WINDS INCREASE TO GALES TO 40 KTS SATURDAY NIGHT INTO SUNDAY. MORE HEAVY FREEZING SPRAY WILL OCCUR AT THIS TIME AS WELL. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY FROM 9 PM EST /8 PM CST/ THIS EVENING TO 10 AM EST /9 AM CST/ WEDNESDAY FOR MIZ002-009-010-084. LAKE EFFECT SNOW ADVISORY FROM 1 PM WEDNESDAY TO 1 PM EST THURSDAY FOR MIZ001-003. LAKESHORE FLOOD ADVISORY FROM 6 AM WEDNESDAY TO MIDNIGHT EST WEDNESDAY NIGHT FOR MIZ001-003. WIND CHILL ADVISORY FROM 11 PM EST /10 PM CST/ THIS EVENING TO 10 AM EST /9 AM CST/ WEDNESDAY FOR MIZ004-005-011-012. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263>267. GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ244- 245-264>267. GALE WARNING FROM 7 PM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ249>251. GALE WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246>248. HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246-247. GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-241>243-263. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...07 MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
429 PM EST TUE DEC 30 2014 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY) ISSUED AT 427 PM EST TUE DEC 30 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A PROMINENT MID/UPPER LEVEL RIDGE FROM THE ERN PACIFIC INTO BC AND A TROUGH OVER NE CANADA RESULTING IN NNW FLOW TOWARD NRN ONTARIO AND THE NRN LAKES. A SHORTWAVE TROUGH AXIS EXTENDED FROM JAMES BAY INTO SE NORTH DAKOTA. WITH ONLY WEAK FORCING AND LITTLE MOISTURE AVAILABLE...NO PCPN WAS ASSOCIATED WITH THIS FEATURE. FURTHER UPSTREAM...A STRONGER SHRTWV WAS MOVING THROUGH NRN SASK/MANITOBA. AT THE SFC...W TO WNW FLOW PREVAILED ACROSS UPPER MI AND LAKE SUPERIOR AS 1048 MB HIGH PRES CONTINUES TO SINK THROUGH THE NRN AND CNTRL PLAINS. EVEN WITH 850 MB TEMPS NEAR -23C...SATELLITE/RADAR INDICATED ONLY LIGHT TO MODERATE LES INTO NW UPPER MI AND EAST OF MUNISING AS INVERSION HEIGHTS REMAINED NEAR 4K FT WITH VERY DRY AIR UPSTREAM. TONIGHT...EXPECT WINDS TO GRADUALLY BACK TO SW AHEAD OF THE SASK/MANITOBA SHRTWV WHICH WILL PUSH THE LES MOSTLY OFFSHORE. HOWEVER...ADDITIONAL SNOWFALL AMOUNTS OF 1 TO 3 INCHES NW(KEWEENAW AND 2 TO 4 INCHES NE (NE OF P53) ARE POSSIBLE. TEMPS FALLING OFF INTO THE -7F TO -12F RANGE AND WINDS NEAR 10 MPH WILL DROP WIND CHILLS INTO THE -20 TO -33 RANGE OVER THE INTERIOR WRN HALF WHERE WIND CHILL ADVISORIES WILL REMAIN IN EFFECT. WEDNESDAY...AS THE SHRTWV MOVES THROUGH THE NRN LAKES AND DRAGS A WEAK TROUGH THE AREA...WINDS WILL VEER AGAIN FROM SW TO W BY AFTERNOON. THIS WILL BRING THE LES INTO THE NRN KEWEENAW BY MIDDAY AND INTO MUCH OF THE REST OF THE PENINSULA BY MID TO LATE AFTERNOON. THE COMBINATION OF THE LES AND WIND GUSTS OVER 40 MPH WILL LEAD TO VERY POOR VSBY WHICH WILL LINGER INTO THE EVENING...PROMPTING THE ISSUANCE OF AN LES ADVY. ALTHOUGH THERE WILL BE A PERIOD OF DEEPER MOISTURE THAT SHOULD INTENSIFY LES...THE SHIFTING WIND DIRECTIONS SHOULD LIMIT OVERALL AMOUNTS TO THE 1 TO 3 INCH RANGE BY EVENING. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 427 PM EST TUE DEC 30 2014 UPPER AIR PATTERN STARTS OUT WITH TROUGHING ANCHORED OVER HUDSON BAY AND ANOTHER MORE COMPACT TROUGH OVER DESERT SOUTHWEST OF CONUS. ONLY RIDGING OF NOTE IS OVER THE EASTERN PACIFIC OCEAN INTO FAR WESTERN CANADA. ATTENTION THIS WEEKEND WILL BE ON THE SOUTHWEST CONUS TROUGH. MODELS CONTINUE TO FAVOR IDEA THAT AS STRONG JET ENERGY ADVANCES AHEAD OF TROUGH...IT WILL EMERGE OVER THE SOUTHERN PLAINS ON SATURDAY AND LIFT OVER THE GREAT LAKES ON SUNDAY. MEANWHILE...ANOTHER SHORTWAVE WITHIN THE BASE OF LARGER TROUGHING OVER EASTERN CANADA WILL WORK OVER THE UPPER GREAT LAKES. ONE OR BOTH OF THESE FEATURES MAY BRING WIDESPREAD SNOW TO UPR MICHIGAN FRIDAY NIGHT THROUGH SATURDAY NIGHT. THERE IS POTENTIAL THAT THE TWO FEATURES COULD PHASE...THOUGH THAT IS NOT CERTAIN...AND THAT WOULD RESULT IN GREATEST CHANCE OF SEEING HIGHER END SNOW EVENT. NO MATTER HOW IT SHAKES OUT...THERE ARE INDICATIONS VERY CHILLY AIRMASS...EVEN COLDER THAN ONE CURRENTLY AFFECTING THE REGION...WILL SETTLE OVER UPR GREAT LAKES BY EARLY NEXT WEEK. BEYOND END OF EXTENDED THERE ARE SIGNALS THAT RIDGE OVER EAST PACIFIC BREAKS DOWN AND MORE MILD AIR RETURNS TO MUCH OF THE CONUS. PATTERN SHIFT THE CFSV2 HAS BEEN SHOWING FOR A WHILE NOW. THUS...OVERALL IT DOES NOT APPEAR THAT THE UPCOMING COLD WILL BE THAT LONG LASTING. INTIALLY THE MAIN ISSUE WILL BE THE ONGOING WEST FLOW LAKE EFFECT AND BLOWING SNOW WITH POOR VSBY OVER THE KEWEENAW. DECENT AGREEMENT THAT SHORTWAVE DROPPING WNW-ESE OVER LK SUPERIOR AND UPR MICHIGAN WEDNESDAY EVENING WITH LEADING SFC TROUGH AND ENHANCED CONVERGENCE AND ADDITIONAL MOISTURE WILL RESULT IN A A BRIEF PERIOD OF MODERATE TO HEAVY LES. WIND CORE MAX AT 950-925MB OVER 40 KTS WILL BE EASING BY WEDNESDAY EVENING...BUT MIXED LAYER WINDS UP TO 40 KTS WILL STILL RESULT IN STRONG/GUSTY WINDS OVER 30 MPH AND BLSN/POOR VSBY. SOUNDINGS SHOW MARGINAL MOISTURE AND INSTABILITY FOR SIGNIFICANT LES THOUGH AFTER THE TROUGH PASSAGE WITH INVERSIONS PEAKING AT 5-7 KFT AGL WEDNESDAY EVENING AND LAKE INDUCED EQL NOT MUCH HIGHER THAN THAT. MAJORITY OF THE MOIST LAYER IS WITHIN THE DGZ BUT STRONG WINDS WILL LIKELY CUT DOWN SLR/S. POOR VSBY WILL BE THE BIGGER STORY COMPARED TO SNOW AMOUNTS. AFTER COORDINATING WITH SHORT TERM FORECASTER... DECIDED TO GO WITH LAKE EFFECT SNOW ADVISORY FOR SNOW AND BLOWING SNOW WEDNESDAY AFTN THROUGH EARLY AFTERNOON ON NEW YEARS DAY. WILL MENTION OCCASIONAL WHITEOUT CONDITIONS IN THE WSW STATEMENT. LAKE EFFECT AND BLOWING SNOW BECOME FACTOR LATE WEDNESDAY NIGHT INTO THURSDAY FOR AREAS FAVORED BY WNW WINDS...ONTONAGON COUNTY OVER THE WEST AND IN THE SNOW BELTS OF EASTERN HALF OF UPR MICHIGAN. LOOKING AT ONLY A PURE LES SETUP AS SOUNDINGS SHOW SHARP DRYING ABOVE 8KFT. TEMPS AT TOP OF INVERSION BLO -20C LEAD TO MARGINAL INSTABILITY GIVEN WATER TEMPS 2-3C. MOST OF LAKE CONVECTIVE LAYER WILL BE IN THE DGZ AND WINDS WILL BE DIMINISHING...SO FLUFF FACTOR WILL PLAY MORE OF A ROLE. OVERALL...ADVY SNOW AMOUNTS SEEM POSSIBLE INTO NEW YEARS DAY FOR THE WNW FLOW AREAS. LAKE EFFECT LINGERS FOR WNW FLOW AREAS INTO FRIDAY...BUT WILL CONTINUE TO DIMINISH AS HIGH PRESSURE RIDGE SLIDES ACROSS WESTERN GREAT LAKES. COLD WILL SLOWLY EASE...THOUGH TEMPS WELL BLO ZERO EXPECTED THURSDAY NIGHT OVER INTERIOR CNTRL UPR MICHIGAN. INCREASE OF MID CLOUDS MAY RESULT IN LESS TEMP DROP OVER WEST CWA. MAIN QUESTION THIS WEEKEND IS HOW MUCH PHASING OCCURS BTWN APPROACHING NORTHERN STREAM SHORTWAVE TROUGH AND THE UPPER LOW OPENING UP AS IT LIFTS INTO THE CNTRL PLAINS FM THE SOUTHWEST CONUS. SINCE MAJORITY OF JET ENERGY REMAINS AHEAD OF THE SOUTHERN STREAM TROUGH...WOULD EXPECT IT TO STAY FAIRLY PROGRESSIVE AND HAVE LESS CHANCE OF PHASING WITH NORTHERN STREAM SYSTEM. EVEN SO...THE NORTHERN STREAM SHORTWAVE ALONG WITH INCREASING NNE-NNW FLOW WITH H85 TEMPS BLO -12C SATURDAY NIGHT INTO SUNDAY MAY LEAD TO SEVERAL INCHES OF SNOW. BEST SHOT OF SYNOPTIC SNOW WOULD BE OVER THE SOUTH AND EAST CWA WHILE THE GREATEST CHANCE FOR LAKE ENHANCEMENT WOULD BE OVER THE WEST AND NORTH CENTRAL CWA. TIGHT PRESSURE GRADIENT RESULTS IN GUSTY WINDS AND BLOWING SNOW AS WELL. MODEL TRENDS FOR THIS SYSTEM ARE VARIABLE WITH EARLIER RUNS A FEW DAYS AGO SHOWING A WRAPPED UP SYSTEM AND RECENT RUNS BACKING AWAY FM THAT. LATEST RUNS SEEM TO BE TRYING TO COME BACK TO AT LEAST A FARTHER WEST TRACK TO THE SOUTHERN STREAM SYSTEM IF NOT A MORE PHASED SYSTEM. SYSTEM BEARS WATCHING AS IT COULD RESULT IN SOME HEADLINES. BEHIND THE SYSTEM...LOOKS VERY COLD WITH H85 TEMPS DOWN TO -28C BY NEXT MONDAY. INCREASED POPS FOR LAKE EFFECT IN WNW-W FLOW AREAS. MAJORITY OF LAKE CONVECTIVE LAYER IS AT TEMPS BLO -20C...SO SLR/S WILL BE LOW AND MAIN PROBLEM COULD BE POOR VSBY. COULD ALSO HAVE WIND CHILL ISSUES FOR THE FIRST DAY BACK TO SCHOOL AFTER WINTER VACATION. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1249 PM EST TUE DEC 30 2014 LAKE EFFECT SNOW WILL FAVOR PERSISTENT MVFR CIGS AND IFR/LIFR VSBY AT CMX UNTIL LATE TONIGHT WHEN WINDS BACKING TO SAW WILL PUSH THE LES BANDS OFFSHORE. GUSTY WINDS INTO WED MORNING WILL ALSO REDUCE VSBY WITH BLSN EVEN AS THE LES REMAINS MAINLY OFFSHORE. LAKE EFFECT CLOUDS/SNOW WILL REMAIN NEAR IWD THROUGH THIS AFTERNOON BUT MAY LIFT FAR ENOUGH TO THE NORTH FOR IMPROVING CONDITIONS TO VFR WHICH WILL LAST INTO WED AS WINDS BECOME WSW. AT SAW...MVFR CIGS WITH SOME LIGHT SNOW SHOWERS OR FLURRIES WILL ALSO GIVE WAY TO CLEARING WITH VFR CONDITIONS THIS EVENING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 427 PM EST TUE DEC 30 2014 WEST TO SOUTHWEST GALES 40-45 KTS ARE EXPECTED OVER MOST OF LK SUPERIOR BEGINNING LATER TONIGHT WILL SHIFT TO WEST-NORTHWEST GALES TO 35 KTS LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. IN ADDITION TO THE GALES... HEAVY FREEZING SPRAY WILL AFFECT MOST OF THE LAKE INTO THURSDAY. WINDS DIMINISH TO LESS THAN 25 KTS BY FRIDAY...BUT THE LULL WILL BE BRIEF AS NORTHERLY WINDS INCREASE TO GALES TO 40 KTS SATURDAY NIGHT INTO SUNDAY. MORE HEAVY FREEZING SPRAY WILL OCCUR AT THIS TIME AS WELL. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WIND CHILL ADVISORY FROM 9 PM EST /8 PM CST/ THIS EVENING TO 10 AM EST /9 AM CST/ WEDNESDAY FOR MIZ002-009-010-084. LAKE EFFECT SNOW ADVISORY FROM 1 PM WEDNESDAY TO 1 PM EST THURSDAY FOR MIZ001-003. WIND CHILL ADVISORY FROM 11 PM EST /10 PM CST/ THIS EVENING TO 10 AM EST /9 AM CST/ WEDNESDAY FOR MIZ004-005-011-012. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST /NOON CST/ THURSDAY FOR LSZ240>245-248>251-263>267. GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ244- 245-264>267. GALE WARNING FROM 7 PM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ249>251. GALE WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246>248. HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246-247. GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-241>243-263. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...JLA AVIATION...JLB MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1133 PM EST MON DEC 29 2014 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 403 PM EST MON DEC 29 2014 WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH EXTENDING FROM NRN QUEBEC THROUGH THE NRN PLAINS INTO THE ROCKIES. THE NEXT SIGNIFICANT UPSTREAM SHORTWAVE TROUGH WAS DROPPING SOUTH THROUGH NRN SASK/MANITOBA. AT THE SFC...1054 MB ARCTIC HIGH PRES OVER ALBERTA EXTENDED INTO THE NRN PLAINS AND UPPER MS VALLEY AND NRN LAKES RESULTING IN A FLOW OF VERY COLD AIR ACROSS LAKE SUPERIOR ON NW WINDS. DESPITE 850 MB TEMPS NEAR -21C...LES HAS BEEN LIMITED BY THE VERY DRY UPSTREAM CONDITIONS AS THE BACK EDGE OF THE CLOUDS WAS CLOSER TO THE MI SHORE IN THE WEST AND NEAR THE CENTER OF THE NRN LAKE. RADAR SHOWED MAINLY WEAK WIND PARALLEL BANDS INTO THE ERN CWA. TONIGHT...WITH THE LOSS OF DAYTIME MIXING AND ONSET OF LAND BREEZES THE LES MAY BECOME BETTER ORGANIZED. THE PERSISTENT 290-300 FLOW LES IS EXPECTED TO CONTINUE BUT WILL BE LIMITED BY 4K FT INVERSION HEIGHTS AND A LACK OF ANY SUSTAINED AREAS OF LOW LEVEL CONV. THE LONGER FETCH INTO THE EAST WILL SUPPORT SNOWFALL AMOUNTS IN THE 2 TO 4 INCH RANGE WITH SLR VALUES NEAR 25/1...E OF MUNISING WHILE OVER THE WEST ONLY 1 TO 3 INCH AMOUNTS ARE EXPECTED. WIND CHILL VALUES OVER THE INTERIOR WEST COULD FALL INTO THE -20 TO -25 RANGE AS SFC TEMPS DROP TO AROUND -8F. HOWEVER...WINDS SHOULD REMAIN LESS THAN 10 MPH. TUESDAY...EXPECT THE WINDS TO BACK MORE WRLY AHEAD OF THE SASK/MANITOBA SHORTWAVE TROUGH...ESPECIALLY IN THE AFTERNOON. OTHERWISE...LIGHT TO MODERATE WNW FLOW LES WILL CONTINUE WITH 850 MB TEMPS REMAINING NEAR -22C AND INVERSION HEIGHTS AROUND 4K FT. THE STRONGEST LOW LEVEL CONV...INFLUENCED BY LAKE-INDUCED TROUGHING IS EXPECTED OVER THE ERN LAKE WITH SOME STRONGER BANDS POSSIBLE CLIPPING THE NE PORTION OF LUCE COUNTY. FOR NOW...EXPECT ADDITIONAL ACCUMULATIONS IN THE 2 TO 4 INCH RANGE E OF P53 AND 1 TO 3 INCHES INTO THE WEST. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 426 PM EST MON DEC 29 2014 A BROAD UPPER TROUGH OVER CANADA AND THE GREAT LAKES REGION WILL LEAD TO BELOW NORMAL TEMPERATURES AND PERIODS OF LAKE EFFECT SNOW THROUGH THE FIRST WEEK OF 2015. AT THE START OF THE PERIOD...THE AREA WILL STILL BE BETWEEN A STRONG HIGH OVER WESTERN NEBRASKA AND A LOW JUST TO THE NORTH OF HUDSON BAY. ALOFT...A SHORTWAVE WILL JUST BE DEPARTING THE AREA AND BRINGING ONE LAST SURGE OF -21C 850MB TEMPS TO THE AREA. THUS...EXPECT NORTHWEST FLOW LAKE EFFECT TO STILL BE ONGOING TUESDAY EVENING. A SURFACE TROUGH DIVING SOUTHEAST FROM THE HUDSON BAY LOW WILL LEAD TO BACKING FLOW ON TUESDAY NIGHT INTO WEDNESDAY MORNING...SHIFTING THE LAKE EFFECT TO THE WESTERLY FLOW AREAS (THE KEWEEANW AND RIGHT ALONG THE LAKE SUPERIOR SHORELINE EAST OF MUNISING). SNOWFALL AMOUNTS TUESDAY NIGHT CONTINUE TO LOOK LIGHT AND FLUFFY AS INVERSION HEIGHTS ARE STILL IN THE 4-5KFT RANGE WITH MUCH OF THE CLOUD LAYER IN THE DGZ. WILL FOLLOW THE SNOWFALL AMOUNTS SEEN OVER THE LAST 12/24HRS AND HAVE THEM BE IN THE 1-4IN/12HRS RANGE. TUESDAY NIGHT WILL BE ANOTHER COLD NIGHT AWAY FROM THE LAKE EFFECT CLOUDS...WITH LOWS FALLING INTO THE SINGLE DIGITS AND LOWER TEENS BELOW ZERO. WIND CHILLS WILL BECOME A CONCERN LATE IN THE NIGHT INTO WEDNESDAY MORNING...AS THE WEST TO SOUTHWEST WINDS BEGIN TO INCREASE WITH THE TIGHTENING PRESSURE GRADIENT. WHILE THIS WILL LIKELY INCREASE MIXING AND IN TURN WARM TEMPS SLIGHTLY (HELPED BY SOME MID CLOUDS MOVING IN)...THERE WILL STILL BE A PERIOD LATE TUESDAY NIGHT INTO WEDNESDAY MORNING WHERE WIND CHILL VALUES WILL BE IN THE -20 TO -30 DEGREE RANGE OVER THE INTERIOR LOCATIONS. WILL CONTINUE TO MENTION THIS IN THE HWO AND AN ADVISORY MAY BEEN NEEDED TOMORROW. WITH THE LOW LEVEL WINDS TRYING TO BACK TOWARDS THE SOUTHWEST DURING THE DAY WEDNESDAY...DID TRY TO SHOW BETTER TIMING ON THE LAKE EFFECT SNOW. EXPECT IT TO TRY TO SHIFT OVER THE FAR NORTHERN PART OF THE KEWEENAW BY MID DAY AND WELL OFFSHORE OVER THE EAST. WINDS WILL BECOME QUITE GUSTY DURING THIS PERIOD...WITH MUCH OF UPPER MICHIGAN EXPERIENCING GUSTS IN THE 25 TO 35MPH RANGE. BUT OVER THE KEWEENAW PENINSULA AND CLOSER TO THE TIGHTER PRESSURE GRADIENT...WOULD EXPECT GUSTS TO AT LEAST 40 MPH AND AT TIMES 45-50MPH. THESE WINDS COMBINED WITH THE FLUFFY LAKE EFFECT SEEN OVER THE LAST COUPLE OF DAYS WILL LIKELY LEAD TO SIGNIFICANT BLOWING SNOW DEVELOPING THROUGH THE DAY WEDNESDAY. THEN...AS STRONG SHORTWAVE DIVES SOUTHEAST ACROSS THE UPPER GREAT LAKES REGION DURING THE AFTERNOON AND THE SURFACE TROUGH DURING THE EARLY EVENING...EXPECT WINDS TO SHIFT BACK TO THE WEST AND REFOCUS THE LAKE EFFECT IN THE WESTERLY WIND AREAS. THINK THERE COULD BE A PERIOD OF MODERATE SNOW AS THE WINDS TURN TO THE WEST...DUE TO INVERSION HEIGHTS RISING TO 7KFT AND MUCH OF THE CLOUD STILL IN THE DGZ. THERE ARE A COUPLE DOWNSIDES TO HIGHER SNOWFALL AMOUNTS (TIED TO THE STRONG WINDS)...BUT THERE WILL STILL BE VERY POOR CONDITIONS OVER THE KEWEENAW. FIRST...THE HIGH WINDS WILL LIMIT THE RESIDENCE TIME OVER THE WESTERN LAKE AS THEY SHIFT TO THE WEST. SECOND...THE STRONG WINDS WILL BREAK UP THE DENDRITES FROM THE FAVORABLE CLOUD LAYER AND LEAD TO SMALLER/FRACTURED FLAKES. WHILE THIS WILL LIMIT SNOWFALL AMOUNTS...IT WILL BE MORE EFFECTIVE AT REDUCING VISIBILITIES AND WHEN COMBINED WITH THE BLOWING SNOW...WOULD EXPECT VISIBILITIES BELOW 1/4 MILE AT TIMES LATE WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. WILL CONTINUE TO MENTION THESE POOR CONDITIONS FOR THE KEWEENAW IN THE HWO. EXPECT NORTHWEST FLOW LAKE EFFECT TO REESTABLISH ON THURSDAY FOR AREAS DOWNSTREAM FROM LAKE SUPERIOR. ELSEWHERE IN THE U.P...MODELS DIFFER IN THEIR SOLUTIONS ON POTENTIAL SHORTWAVES ZIPPING EAST-SOUTHEAST ACROSS THE AREA. AT TIMES...MODELS HAVE SHOWN LIGHT SNOW ASSOCIATED WITH THESE QUICK WAVES THURSDAY AND AGAIN FRIDAY. BOTH STRENGTH AND LOCATIONS HAS NOT BEEN CONSISTENT IN THE MODELS OVER THE LAST 24 HOURS...SO WILL FOCUS LARGELY ON LAKE EFFECT TURNING TO THE WESTERLY WIND LOCATIONS AND SHOW SLIGHT CHANCES ELSEWHERE. THE UNCERTAINTY CONTINUES INTO THE WEEKEND...AS MODELS DIFFER ON HOW THE CLOSED UPPER LOW THAT DEVELOPS OVER THE SOUTHWEST CONUS TUESDAY INTERACTS WITH THE NORTHERN STREAM JET AS IT SHIFTS EAST ACROSS THE SOUTHERN CONUS. THE 12Z GFS/GEM SOLUTIONS MERGE THE UPPER LOW WITH A MORE AMPLIFIED NORTHERN STREAM TROUGH AND THEN LIFT IT AND A DEVELOPING SURFACE LOW NORTHEAST THROUGH THE LOWER GREAT LAKES SATURDAY NIGHT. MEANWHILE...THE 12Z ECMWF AND ITS ENSEMBLE MEMBERS SHOW A MUCH FLATTER NORTHERN STREAM TROUGH AND DON/T MERGE THE WAVES UNTIL THE EAST COAST ON SUNDAY. THAT WOULD LEAD TO MORE OF A NORTHERLY FLOW LAKE EFFECT FOR THE AREA. THIS WILL DEFINITELY BE SOMETHING TO WATCH OVER THE COMING DAYS. EVEN IF THERE ISN/T A LOW MOVING THROUGH THE LOWER GREAT LAKES...TEMPERATURES WILL BE COLD ENOUGH FOR LAKE EFFECT SNOW AND WILL CONTINUE TO SHOW THE POTENTIAL IN THE GRIDS FOR AREAS NEAR LAKE SUPERIOR. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1133 PM EST MON DEC 29 2014 EXPECT MAINLY MVFR CONDITIONS AT IWD/CMX THROUGH THE PERIOD...WITH BETTER CONDITIONS AT SAW. THERE COULD BE TEMPORARY IFR CONDITIONS FOR VISIBILITY IN THE HEAVIER SNOW SHOWERS ESPECIALLY AT CMX. LIKE LAST NIGHT...THERE WILL BE TEMPORARY MVFR CIGS AT SAW OVERNIGHT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 403 PM EST MON DEC 29 2014 EXPECT HEAVY FREEZING SPRAY BY TUESDAY AFTERNOON AND GALES FROM LATE TUESDAY NIGHT THROUGH THURSDAY MORNING. A RIDGE ACROSS THE UPPER GREAT LAKES WILL BUILD TUESDAY...AS VERY STRONG ARCTIC HIGH PRESSURE INITIALLY AT 31.3 INCHES OVER SW CANADA SINKS ACROSS MONTANA. LOOK FOR THE RIDGE OVER LAKE SUPERIOR TO SINK SOUTH TUESDAY NIGHT. THIS WILL BE AS A HUDSON BAY LOW DRAGS A TROUGH ACROSS LAKE SUPERIOR. THE LOW WILL DEEPEN OVER S HUDSON BAY WEDNESDAY NIGHT AS IT BRINGS A REINFORCING TROUGH ACROSS LAKE SUPERIOR. W GALES OF 35-45KTS ARE STILL ANTICIPATED /ALONG WITH HEAVY FREEZING SPRAY TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE PRESSURE GRADIENT TIGHTENS BETWEEN THE EXITING HIGH TO THE S AND STRONG LOW TO THE N. LOOK FOR THE LOW TO SHIFT ACROSS N QUEBEC AND WEAKEN SIGNIFICANTLY THURSDAY NIGHT. HIGH PRESSURE WILL THEN BUILD SE ACROSS SASKATCHEWAN AND S MANITOBA ON THURSDAY AND FRIDAY AS A RIDGE TRACKS ACROSS THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ TUESDAY TO 1 PM EST /NOON CST/ THURSDAY FOR LSZ240>243-248>251-263- 265>267. GALE WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ244- 245-264>267. HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ TUESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162. GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ WEDNESDAY TO 7 AM EST /6 AM CST/ THURSDAY FOR LSZ162-241>243-263. HEAVY FREEZING SPRAY WARNING UNTIL 1 PM EST THURSDAY FOR LSZ244- 245-264. HEAVY FREEZING SPRAY WARNING FROM 1 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LSZ246-247. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING FROM 10 AM WEDNESDAY TO 1 PM EST THURSDAY FOR LMZ221-248-250. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
924 PM EST WED DEC 31 2014 .SYNOPSIS... A COLD FRONT WILL BRING THE POTENTIAL FOR LAKE SNOWS NORTH OF THE NEW YORK THRUWAY THURSDAY NIGHT AND FRIDAY. ON SATURDAY AFTERNOON, A STORM SYSTEM WILL MOVE IN FROM THE OHIO VALLEY, BRINGING A MIX OF RAIN AND SNOW SATURDAY NIGHT. && .NEAR TERM /UNTIL 8 AM THURSDAY MORNING/... 920 PM UPDATE... THE LAKE EFFECT SNOW BAND OVER THE NORTH COUNTRY IS PROGGED TO SKIRT NORTHERN ONEIDA COUNTY BETWEEN 7Z AND 10Z, BRINGING LIGHT SNOW ACCUMULATION. LATEST HRRR OUTPUT SUGGESTS A FEW FLURRIES OR LIGHT SNOW SHOWERS MAY SNEAK INTO NORTHWESTERN STEUBEN COUNTY OVERNIGHT, DUE TO A FLUCTUATING ERIE BAND. ADDED A SLIGHT CHC POP. INTERIOR VALLEY TEMPERATURES ARE ALREADY NEAR PROJECTED OVERNIGHT MINS, SO HAVE ADJUSTED MINS DOWNWARD. 1255 PM UPDATE... LAKE SNOWS HV EXITED NRN ONEIDA CNTY THUS HV CANCELLED THE WARNING. EXPECT LK EFFECT SNOW TO RMN WELL TO THE NORTH ON 240-250 FLOW THRU THE OVRNGT WITH A SLIGHT WOBBLE TO THE SOUTH POSSIBLE TWD 09Z WITH PERHAPS A FEW LGT SNOW SHOWERS AND/OR FLURRIES SNEAKING INTO EXTREME NRN ONEIDA THRU DAYBREAK. VRY MINIMAL ACCUMS ARE EXPECTED WITH THIS WOBBLE. EXPECTING THAT LK ERIE BAND WL STAY A TAD TOO FAR WEST TO AFFECT FINGER LAKES THIS EVNG INTO THE OVRNGT. NOTHING MORE THAN CLD CVR EXPECTED ON 240 DEGREE FLOW. EXPECT MINS TO DROP INTO THE LWR TEENS BY MRNG WITH SINGLE DIGITS POSSIBLE IN NOTORIOUSLY COLDER VALLEYS. && .SHORT TERM /8 AM THURSDAY MORNING THROUGH SATURDAY/... 245 PM UPDATE... LAKE EFFECT SNOW WL RMN NORTH OF CWA FOR MOST OF TOMORROW. THERE IS SOME INDICATION THAT SNOW BAND WL MAKE A RUN TWD THE SOUTH ARND 18Z BUT QUICKLY RETREAT BACK TO THE NORTH AS WINDS BACK TWD THE SOUTH AHD OF APPCHG CDFNT. HV MAINLY CONFINED 20-30 POPS FOR LOCATIONS NORTH OF THE NY THRUWAY DRG THE AFTN HRS. AS WINDS GO SRLY TEMPS WL WARM INTO THE 20S BY AFTN, WRMR THAN TDA THO STILL BLO NRML VALUES. CDFNT WL SLIP SOUTH THRU SRN CANADA LATE THUR NGT WITH LK SNOWS DVLPNG AHD OF AND ALONG THIS BNDRY. MODELS SEEM TO BE IN PRETTY GOOD AGREEMENT WITH FROPA WITH ONLY SVR HRS DIFFERENCE ON TIMING. THUS EXPECT LK EFFECT SNOW SHOWERS TO COMMENCE LATE EVNG AND TWD MIDNIGHT WITH LKLY BAND OF SNOW SHOWERS DROPPING INTO NRN ONEIDA AFTER 08Z. WL ALLOW LATER SHIFTS TO GET A BETTER HANDLE ON ANY POTENTIAL HEADLINES FOR LK EFFECT EVENT TOMORROW NIGHT/FRI MRNG. GFS AND NAM DIFFER ON HOW LONG FLOW WL BE ALIGNED FOR FAVORABLE LK SNOWS ON FRIDAY. NAM PUSHES FRONT THRU QUICKLY AND ALLOWS DRIER AIR TO DISRUPT SNOWS DRG THE AFTN WHILE GFS KEEP INVERSION UP ARND 800MB DRG THE AFTN HRS WITH FAIRLY STEADY STATE 280 DEGREE FLOW. FEEL IT PRUDENT TO HOLD OFF ON ANY HEADLINES AT THIS TIME DUE TO VARYING DEGREES OF UNCERTAINTY. SFC HIPRES WL BEGIN BUILDING IN LATE FRI NGT THO SOME REMNANT SNOWS MAY STILL EXIST NORTH OF THE THRUWAY THRU 06Z SAT. QUIET WX EXPECTED UNTIL SYSTEM MVS IN FM THE SOUTH AFT 18Z SATURDAY. COLD AIR DAMMING PROGGED ACRS ERN ZONES THRU END OF SHORT TERM PD THUS PCPN WL MV IN AS ALL SNOW THRU 00Z SUN. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MAIN FOCUS CONTINUES TO BE EARLY IN THE PERIOD WITH MED RANGE MODELS IN PRETTY GOOD SYNOPTIC AGREEMENT THAT A PHASING SOUTHERN STREAM/NORTHERN STREAM TROF WILL EJECT A SFC LOW THROUGH THE GREAT LAKES REGION AND EASTERN ONTARIO/QUEBEC ON SATURDAY NIGHT AND SUNDAY. THIS IS, OF COURSE, A TRACK THAT SIGNALS A SNOW-TO-MIX-TO-RAIN EVENT FOR CNY/NEPA...FOLLOWED BY A DRY SLOT AND SHOWERY PRECIPITATION ON THE BACK SIDE SUN-MON. GIVEN THE MODEL AGREEMENT AND TRENDS...THIS IS A FAIRLY HIGH CONFIDENCE EVENT SO WILL CONTINUE WITH CAT POP ALREADY OFFERED BY PREVIOUS FCST. BEYOND MONDAY...A BROAD UPPER LEVEL TROF RESIDENT ACROSS THE NORTHEAST AND GTLKS WILL MAINTAIN A COLD AND UNSTABLE WEST-NW FLOW WITH TRANSIENT UPPER LEVEL WAVES GENERATING PERIODS OF LAKE SNOW RESPONSES TO THE EAST OF ERIE AND ONTARIO. HAVE PRETTY MUCH CONSTANT CHANCES FOR SNOW SHOWERS OR FLURRIES GOING THROUGH WEDNESDAY. WITH THE EXCEPTION OF AN ABNORMALLY MILD SUNDAY...TEMPERATURES WILL BE AT OR BELOW NORMAL DURING THIS TIME. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... VFR IS EXPECTED FOR THE NEXT 24 HOURS. AT KSYR/KRME, BKN CIGS AROUND 4K FT ARE FORECAST THROUGH THE PERIOD FROM LAKE CLOUDS OFF LAKE ERIE. REST OF TAF SITES JUST SCT CLOUDS AROUND 5K FT OR SCT CI. SOUTHWEST WINDS AROUND 10 KNOTS AND GUSTING AT KSYR NEAR 20 KNOTS. WINDS WILL INCREASE THURSDAY MORNING AT 10-15 KNOTS WITH GUSTS UP TO 25 KNOTS. OUTLOOK... FRI...VFR. LOCAL MVFR CIG/VSBY IN LE SNOW SHOWERS VCNTY KRME- KSYR...PSBL KITH. SAT/SAT NGT...BECOMING IFR WITH SNOW DEVELOPING...CHANGING TO WINTRY MIX AND OCNL RAIN/FRZG RAIN OVERNIGHT. SUN...VFR. SCT RAIN SHOWERS. MON...MVFR. SCT SNOW SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJP/PVF NEAR TERM...DJP/PVF SHORT TERM...PVF LONG TERM...JAB AVIATION...RRM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1233 PM CST TUE DEC 30 2014 .UPDATE... ISSUED AT 1235 PM CST TUE DEC 30 2014 WE HAVE LET THE WIND CHILL ADVISORY EXPIRE. WIND CHILLS WILL STILL HOVER NEAR 20 BELOW FOR MOST AREAS TODAY...SO STILL COLD. WE MAY NEED A WIND CHILL ADVISORY ONCE AGAIN OVERNIGHT AS WINDS INCREASE FROM THE WEST...SO WILL MONITOR THIS THREAT. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 COLDEST CORE OF AIRMASS IS OVER THE FCST AREA CURRENTLY. A SHORT WAVE TROUGH MOVING SOUTHWARD NOW ALONG THE CANADIAN BORDER AND BEHIND IT BEGINS SLOW WARMING AT THE 850 MB LEVEL LATER TODAY AND TONIGHT. HOW MUCH WARMING WILL THERE BE AT THE SFC REMAINS A QUESTION. TRENDED TOWARD HIGHER GUIDANCE VALUES AS GFS/NAM MOS TEMPS TOO COLD AS MANY AREAS HAVE LIGHT OR MINIMAL SNOW COVER. TO START THE DAY...THERE IS A BAND OF CLOUDS ALONG LEADING EDGE OF THE SHORT WAVE...AND THIS WILL DROP SOUTHWARD THRU THE FCST AREA..LASTING 2-3 HOURS AT ANY ONE PLACE. RAP MODEL 850 RH FIELD SHOWS ITS PROGRESSION NICELY. BEHIND IT IT WILL CLEAR OUT AGAIN. SO THE BALANCE OF THE DAY WILL SEE CONSIDERABLE SUN AND WINDS WILL TURN A BIT MORE WESTERLY. WITH THIS IN MIND DID RAISE MAX TEMPS A FEW DEGREES TO VERY NEAR YESTERDAY`S READINGS WITH ZERO TO 5 ABOVE IN THE IMMEDIATE RRV AND SE ND/WCNTRL MN TO ZERO TO BELOW DVL BASIN AND PARTS OF NW MN ESP AWAY FROM THICKEST FORESTS. HOURLY TEMP AND WIND FCST INDICATE MOST AREAS OUT OF WC ADVISORY 18Z OR SO SO WILL LEAVE THAT IN PLACE. ALLOWED SOME FALL OFF IN TEMPS TONIGHT BUT NOT MUCH AS RISING TEMPS EXPECTED ALONG WITH A BREEZY WEST WIND. WIND CHILLS SHOULD BARELY DROP INTO THE ADV RANGE THIS EVENING BEFORE WARMING KICKS IN. AREA OFFICES HOLDING OFF ON ANY NEW WIND CHILL ADV AS SO MUCH DEPENDS ON HOW WARM IT GETS LATER TODAY AND HOW MUCH TEMP FALLS EARLY THIS EVENING BEFORE SFC WARMING BEGINS. SHORT WAVE WILL DIVE SOUTH THRU NW ONTARIO AND TOWARD MN ARROWHEAD WEDNESDAY. THICKER CLOUD COVER LIKELY NORTH CENTRAL-NORTHEASTERN MN WITH MORE OF A PARTLY CLOUDY REGIME FARTHER WEST. 850 TEMPS DON/T FALL MUCH WEDNESDAY SO NET RESULT WILL BE WARMER AFTN HIGHS WITH TEENS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 AS ADVERTISED FOR THE PAST FEW DAYS...A WEAK SHORT WAVE WILL DIVE SOUTHEAST FROM ALBERTA AND ACROSS NORTH DAKOTA AND INTO MINNESOTA WED NIGHT INTO THURSDAY SPREADING A BAND OF LIGHT SNOW WITH AMOUNTS UNDER 1 INCH. FOR FRIDAY THROUGH TUESDAY...GFS AND ECMWF HAVE COME INTO CLOSE AGREEMENT FOR THE START OF THE PERIOD WITH A MEAN H5 TROF AXIS EXTENDING FROM A HUDSONS BAY LOW INTO THE EASTERN GREAT LAKES WITH A REX BLOCK ALONG THE WESTERN NOAM COAST RESULTING IN SPLIT H5 FLOW OVER THE CONUS...A PATTERN WHICH THEN PERSISTS THROUGH THE PERIOD. THUS WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS WE STAND A GOOD CHANCE FOR MEASURABLE SNOW /A FEW INCHES/ FROM FRIDAY EVENING INTO SATURDAY... WITH MARKEDLY COOLER TEMPS AND ADDITIONAL FLURRIES THROUGH THE EARLY PART OF NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1230 PM CST TUE DEC 30 2014 MOSTLY CLEAR SKIES EXPECT THIS AFTN AND TONIGHT. MAIN AVIATION ISSUE WILL BE WINDS INCREASING OVERNIGHT...BECOMING WSW AND BREEZY ESPECIALLY ACROSS NORTHEASTERN ND. VFR CONDITIONS EXPECTED THROUGHOUT 18Z TAF PERIOD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...DK SHORT TERM...RIDDLE LONG TERM...GUST/RIDDLE AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1001 AM CST TUE DEC 30 2014 .UPDATE... ISSUED AT 958 AM CST TUE DEC 30 2014 NO UPDATE PLANNED AT THIS TIME. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 COLDEST CORE OF AIRMASS IS OVER THE FCST AREA CURRENTLY. A SHORT WAVE TROUGH MOVING SOUTHWARD NOW ALONG THE CANADIAN BORDER AND BEHIND IT BEGINS SLOW WARMING AT THE 850 MB LEVEL LATER TODAY AND TONIGHT. HOW MUCH WARMING WILL THERE BE AT THE SFC REMAINS A QUESTION. TRENDED TOWARD HIGHER GUIDANCE VALUES AS GFS/NAM MOS TEMPS TOO COLD AS MANY AREAS HAVE LIGHT OR MINIMAL SNOW COVER. TO START THE DAY...THERE IS A BAND OF CLOUDS ALONG LEADING EDGE OF THE SHORT WAVE...AND THIS WILL DROP SOUTHWARD THRU THE FCST AREA..LASTING 2-3 HOURS AT ANY ONE PLACE. RAP MODEL 850 RH FIELD SHOWS ITS PROGRESSION NICELY. BEHIND IT IT WILL CLEAR OUT AGAIN. SO THE BALANCE OF THE DAY WILL SEE CONSIDERABLE SUN AND WINDS WILL TURN A BIT MORE WESTERLY. WITH THIS IN MIND DID RAISE MAX TEMPS A FEW DEGREES TO VERY NEAR YESTERDAY`S READINGS WITH ZERO TO 5 ABOVE IN THE IMMEDIATE RRV AND SE ND/WCNTRL MN TO ZERO TO BELOW DVL BASIN AND PARTS OF NW MN ESP AWAY FROM THICKEST FORESTS. HOURLY TEMP AND WIND FCST INDICATE MOST AREAS OUT OF WC ADVISORY 18Z OR SO SO WILL LEAVE THAT IN PLACE. ALLOWED SOME FALL OFF IN TEMPS TONIGHT BUT NOT MUCH AS RISING TEMPS EXPECTED ALONG WITH A BREEZY WEST WIND. WIND CHILLS SHOULD BARELY DROP INTO THE ADV RANGE THIS EVENING BEFORE WARMING KICKS IN. AREA OFFICES HOLDING OFF ON ANY NEW WIND CHILL ADV AS SO MUCH DEPENDS ON HOW WARM IT GETS LATER TODAY AND HOW MUCH TEMP FALLS EARLY THIS EVENING BEFORE SFC WARMING BEGINS. SHORT WAVE WILL DIVE SOUTH THRU NW ONTARIO AND TOWARD MN ARROWHEAD WEDNESDAY. THICKER CLOUD COVER LIKELY NORTH CENTRAL-NORTHEASTERN MN WITH MORE OF A PARTLY CLOUDY REGIME FARTHER WEST. 850 TEMPS DON/T FALL MUCH WEDNESDAY SO NET RESULT WILL BE WARMER AFTN HIGHS WITH TEENS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 AS ADVERTISED FOR THE PAST FEW DAYS...A WEAK SHORT WAVE WILL DIVE SOUTHEAST FROM ALBERTA AND ACROSS NORTH DAKOTA AND INTO MINNESOTA WED NIGHT INTO THURSDAY SPREADING A BAND OF LIGHT SNOW WITH AMOUNTS UNDER 1 INCH. FOR FRIDAY THROUGH TUESDAY...GFS AND ECMWF HAVE COME INTO CLOSE AGREEMENT FOR THE START OF THE PERIOD WITH A MEAN H5 TROF AXIS EXTENDING FROM A HUDSONS BAY LOW INTO THE EASTERN GREAT LAKES WITH A REX BLOCK ALONG THE WESTERN NOAM COAST RESULTING IN SPLIT H5 FLOW OVER THE CONUS...A PATTERN WHICH THEN PERSISTS THROUGH THE PERIOD. THUS WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS WE STAND A GOOD CHANCE FOR MEASURABLE SNOW /A FEW INCHES/ FROM FRIDAY EVENING INTO SATURDAY... WITH MARKEDLY COOLER TEMPS AND ADDITIONAL FLURRIES THROUGH THE EARLY PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 700 AM CST TUE DEC 30 2014 BAND OF VFR CLOUD COVER DROPPING SOUTH. AT 13Z CLOUD BAND WAS CARRINGTON TO GRAND FORKS TO WASKISH. CLEARING BEHIND THIS CLOUD BAND IN NE ND...BUT SCATTERED CLOUDS REMAIN IN SOUTHEASTERN MANITOBA. TIMED CLOUD BAND SOUTHWARD THROUGH THE MORNING INTO FARGO THEN A FEW HOURS OF SCATTERED CLOUDS THEN CLEAR. SOME CIRRUS SPILLING SOUTH TONIGHT. WEST TO NORTHWEST WIND 10 TO 15 KTS TODAY INCREASING 15 TO 25 KTS IN NRN VALLEY OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR NDZ006>008-014>016- 024-026>030-038-039-049-052>054. MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-013>017- 022>024-027>032-040. && $$ UPDATE...DK SHORT TERM...RIDDLE LONG TERM...GUST/RIDDLE AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
709 AM CST TUE DEC 30 2014 .UPDATE... ISSUED AT 700 AM CST TUE DEC 30 2014 NO UPDATES. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 COLDEST CORE OF AIRMASS IS OVER THE FCST AREA CURRENTLY. A SHORT WAVE TROUGH MOVING SOUTHWARD NOW ALONG THE CANADIAN BORDER AND BEHIND IT BEGINS SLOW WARMING AT THE 850 MB LEVEL LATER TODAY AND TONIGHT. HOW MUCH WARMING WILL THERE BE AT THE SFC REMAINS A QUESTION. TRENDED TOWARD HIGHER GUIDANCE VALUES AS GFS/NAM MOS TEMPS TOO COLD AS MANY AREAS HAVE LIGHT OR MINIMAL SNOW COVER. TO START THE DAY...THERE IS A BAND OF CLOUDS ALONG LEADING EDGE OF THE SHORT WAVE...AND THIS WILL DROP SOUTHWARD THRU THE FCST AREA..LASTING 2-3 HOURS AT ANY ONE PLACE. RAP MODEL 850 RH FIELD SHOWS ITS PROGRESSION NICELY. BEHIND IT IT WILL CLEAR OUT AGAIN. SO THE BALANCE OF THE DAY WILL SEE CONSIDERABLE SUN AND WINDS WILL TURN A BIT MORE WESTERLY. WITH THIS IN MIND DID RAISE MAX TEMPS A FEW DEGREES TO VERY NEAR YESTERDAY`S READINGS WITH ZERO TO 5 ABOVE IN THE IMMEDIATE RRV AND SE ND/WCNTRL MN TO ZERO TO BELOW DVL BASIN AND PARTS OF NW MN ESP AWAY FROM THICKEST FORESTS. HOURLY TEMP AND WIND FCST INDICATE MOST AREAS OUT OF WC ADVISORY 18Z OR SO SO WILL LEAVE THAT IN PLACE. ALLOWED SOME FALL OFF IN TEMPS TONIGHT BUT NOT MUCH AS RISING TEMPS EXPECTED ALONG WITH A BREEZY WEST WIND. WIND CHILLS SHOULD BARELY DROP INTO THE ADV RANGE THIS EVENING BEFORE WARMING KICKS IN. AREA OFFICES HOLDING OFF ON ANY NEW WIND CHILL ADV AS SO MUCH DEPENDS ON HOW WARM IT GETS LATER TODAY AND HOW MUCH TEMP FALLS EARLY THIS EVENING BEFORE SFC WARMING BEGINS. SHORT WAVE WILL DIVE SOUTH THRU NW ONTARIO AND TOWARD MN ARROWHEAD WEDNESDAY. THICKER CLOUD COVER LIKELY NORTH CENTRAL-NORTHEASTERN MN WITH MORE OF A PARTLY CLOUDY REGIME FARTHER WEST. 850 TEMPS DONT FALL MUCH WEDNESDAY SO NET RESULT WILL BE WARMER AFTN HIGHS WITH TEENS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 AS ADVERTISED FOR THE PAST FEW DAYS...A WEAK SHORT WAVE WILL DIVE SOUTHEAST FROM ALBERTA AND ACROSS NORTH DAKOTA AND INTO MINNESOTA WED NIGHT INTO THURSDAY SPREADING A BAND OF LIGHT SNOW WITH AMOUNTS UNDER 1 INCH. FOR FRIDAY THROUGH TUESDAY...GFS AND ECMWF HAVE COME INTO CLOSE AGREEMENT FOR THE START OF THE PERIOD WITH A MEAN H5 TROF AXIS EXTENDING FROM A HUDSONS BAY LOW INTO THE EASTERN GREAT LAKES WITH A REX BLOCK ALONG THE WESTERN NOAM COAST RESULTING IN SPLIT H5 FLOW OVER THE CONUS...A PATTERN WHICH THEN PERSISTS THROUGH THE PERIOD. THUS WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS WE STAND A GOOD CHANCE FOR MEASASUREABLE SNOW /A FEW INCHES/ FROM FRIDAY EVENING INTO SATURDAY... WITH MARKEDLY COOLER TEMPS AND ADDITIONAL FLURRIES THROUGH THE EARLY PART OF NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 700 AM CST TUE DEC 30 2014 BAND OF VFR CLOUD COVER DROPPING SOUTH. AT 13Z CLOUD BAND WAS CARRINGTON TO GRAND FORKS TO WASKISH. CLEARING BEHIND THIS CLOUD BAND IN NE ND...BUT SCATTERED CLOUDS REMAIN IN SOUTHEASTERN MANITOBA. TIMED CLOUD BAND SOUTHWARD THROUGH THE MORNING INTO FARGO THEN A FEW HOURS OF SCATTERED CLOUDS THEN CLEAR. SOME CIRRUS SPILLING SOUTH TONIGHT. WEST TO NORTHWEST WIND 10 TO 15 KTS TODAY INCREASING 15 TO 25 KTS IN NRN VALLEY OVERNIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR NDZ006>008-014>016- 024-026>030-038-039-049-052>054. MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-013>017- 022>024-027>032-040. && $$ UPDATE...RIDDLE SHORT TERM...RIDDLE LONG TERM...GUST/RIDDLE AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
341 AM CST TUE DEC 30 2014 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 COLDEST CORE OF AIRMASS IS OVER THE FCST AREA CURRENTLY. A SHORT WAVE TROUGH MOVING SOUTHWARD NOW ALONG THE CANADIAN BORDER AND BEHIND IT BEGINS SLOW WARMING AT THE 850 MB LEVEL LATER TODAY AND TONIGHT. HOW MUCH WARMING WILL THERE BE AT THE SFC REMAINS A QUESTION. TRENDED TOWARD HIGHER GUIDANCE VALUES AS GFS/NAM MOS TEMPS TOO COLD AS MANY AREAS HAVE LIGHT OR MINIMAL SNOW COVER. TO START THE DAY...THERE IS A BAND OF CLOUDS ALONG LEADING EDGE OF THE SHORT WAVE...AND THIS WILL DROP SOUTHWARD THRU THE FCST AREA..LASTING 2-3 HOURS AT ANY ONE PLACE. RAP MODEL 850 RH FIELD SHOWS ITS PROGRESSION NICELY. BEHIND IT IT WILL CLEAR OUT AGAIN. SO THE BALANCE OF THE DAY WILL SEE CONSIDERABLE SUN AND WINDS WILL TURN A BIT MORE WESTERLY. WITH THIS IN MIND DID RAISE MAX TEMPS A FEW DEGREES TO VERY NEAR YESTERDAY`S READINGS WITH ZERO TO 5 ABOVE IN THE IMMEDIATE RRV AND SE ND/WCNTRL MN TO ZERO TO BELOW DVL BASIN AND PARTS OF NW MN ESP AWAY FROM THICKEST FORESTS. HOURLY TEMP AND WIND FCST INDICATE MOST AREAS OUT OF WC ADVISORY 18Z OR SO SO WILL LEAVE THAT IN PLACE. ALLOWED SOME FALL OFF IN TEMPS TONIGHT BUT NOT MUCH AS RISING TEMPS EXPECTED ALONG WITH A BREEZY WEST WIND. WIND CHILLS SHOULD BARELY DROP INTO THE ADV RANGE THIS EVENING BEFORE WARMING KICKS IN. AREA OFFICES HOLDING OFF ON ANY NEW WIND CHILL ADV AS SO MUCH DEPENDS ON HOW WARM IT GETS LATER TODAY AND HOW MUCH TEMP FALLS EARLY THIS EVENING BEFORE SFC WARMING BEGINS. SHORT WAVE WILL DIVE SOUTH THRU NW ONTARIO AND TOWARD MN ARROWHEAD WEDNESDAY. THICKER CLOUD COVER LIKELY NORTH CENTRAL-NORTHEASTERN MN WITH MORE OF A PARTLY CLOUDY REGIME FARTHER WEST. 850 TEMPS DONT FALL MUCH WEDNESDAY SO NET RESULT WILL BE WARMER AFTN HIGHS WITH TEENS. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 332 AM CST TUE DEC 30 2014 AS ADVERTISED FOR THE PAST FEW DAYS...A WEAK SHORT WAVE WILL DIVE SOUTHEAST FROM ALBERTA AND ACROSS NORTH DAKOTA AND INTO MINNESOTA WED NIGHT INTO THURSDAY SPREADING A BAND OF LIGHT SNOW WITH AMOUNTS UNDER 1 INCH. FOR FRIDAY THROUGH TUESDAY...GFS AND ECMWF HAVE COME INTO CLOSE AGREEMENT FOR THE START OF THE PERIOD WITH A MEAN H5 TROF AXIS EXTENDING FROM A HUDSONS BAY LOW INTO THE EASTERN GREAT LAKES WITH A REX BLOCK ALONG THE WESTERN NOAM COAST RESULTING IN SPLIT H5 FLOW OVER THE CONUS...A PATTERN WHICH THEN PERSISTS THROUGH THE PERIOD. THUS WITH NORTHWEST FLOW OVER THE NORTHERN PLAINS WE STAND A GOOD CHANCE FOR MEASASUREABLE SNOW /A FEW INCHES/ FROM FRIDAY EVENING INTO SATURDAY... WITH MARKEDLY COOLER TEMPS AND ADDITIONAL FLURRIES THROUGH THE EARLY PART OF NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1127 PM CST MON DEC 29 2014 NARROW BAND OF MAINLY SCT/BKN MID LEVEL CLOUDS ASSOCIATED WITH A WEAK BOUNDARY WILL AFFECT THE NORTH HALF OF THE FA THROUGH 12Z. AFTER THAT NOT SURE HOW MUCH CLOUD COVER WILL BE LEFT AS MODELS GENERALLY WASH OUT BOUNDARY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR NDZ006>008-014>016- 024-026>030-038-039-049-052>054. MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-013>017- 022>024-027>032-040. && $$ SHORT TERM...RIDDLE LONG TERM...GUST/RIDDLE AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
408 PM EST TUE DEC 30 2014 .SYNOPSIS... HIGH PRESSURE AND A DRY AIRMASS WILL REMAIN IN PLACE ACROSS THE AREA THROUGH FRIDAY. A LOW PRESSURE SYSTEM WILL LIFT NORTHEAST ACROSS THE REGION THIS WEEKEND...BRINGING THE NEXT CHANCE FOR PRECIPITATION. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... INCREASING LOW LEVEL LAPSE RATES ACROSS NORTHERN INDIANA AND NORTHWEST OHIO HAVE LED TO SOME SCATTERED SNOW SHOWER/FLURRY DEVELOPMENT THIS AFTERNOON. THIS MAY BECOME A BIT MORE WIDESPREAD ACROSS OUR NORTHWEST OVER THE NEXT HOUR OR SO BUT WOULD EXPECT TO SEE A DOWNTURN IN COVERAGE THROUGH THE EVENING HOURS AS THE LOW LEVEL LAPSE RATES BEGIN TO DECREASE AGAIN. WILL THEREFORE JUST INCLUDE A CHANCE OF A FLURRY ACROSS PARTS OF OUR NORTHWEST THROUGH MID EVENING. THE CLOUDS ARE ALSO LOOKING FAIRLY DIURNAL ON THE VISIBLE SATELLITE IMAGERY SO WOULD EXPECT TO SEE SOME DISSIPATION IN THE CLOUDS THROUGH THE EVENING HOURS TOO. WILL TREND TOWARD A PARTLY CLOUDY SKY NORTH TO MOSTLY CLEAR IN THE SOUTH FOR LATER TONIGHT. EXPECT OVERNIGHT LOWS DOWN INTO THE TEENS ACROSS THE AREA. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... AN ELONGATED AXIS OF SURFACE HIGH PRESSURE WILL REMAIN STRETCHED ACROSS THE OHIO AND TENNESSEE VALLEYS WEDNESDAY INTO THURSDAY. WITH A DRY AIRMASS IN PLACE...EXPECT MAINLY CLEAR SKIES THROUGH MUCH OF THE SHORT TERM PERIOD. WEAK LOW LEVEL CAA WILL CONTINUE INTO WEDNESDAY AND ALLOWING FOR MIXING UP TO ABOUT 900 MB ONLY YIELDS HIGHS RANGING FROM THE LOWER 20S NORTH TO MID/UPPER 20S SOUTH. LOW LEVEL FLOW WILL BEGIN TO SLOWLY BACK WEDNESDAY NIGHT INTO THURSDAY...LEADING TO SOME WEAK DEVELOPING WAA. EXPECT HIGHS ON THURSDAY RANGING FROM THE UPPER 20S NORTH TO LOW/MID 30S SOUTH. THIS WILL ALSO LEAD TO A GRADUAL INCREASING IN CLOUDS FROM THE SOUTH THROUGH THURSDAY NIGHT. && .LONG TERM /FRIDAY THROUGH TUESDAY/... THE CLOSED LOW IN PLACE ACROSS THE SOUTHWEST CONUS EARLIER IN THE WEEK WILL BE MOVING ACROSS THE FOUR CORNERS REGION TOWARD THE PLAINS ON FRIDAY. MODEL RUNS OVER THE PAST COUPLE DAYS HAVE BEEN RATHER CONSISTENT WITH THIS MOVEMENT OF THE UPPER LOW...AS WELL AS DEVELOPING A SOUTHERLY FLOW OUT OF THE GULF OF MEXICO AT THE SAME TIME. MOISTURE SHOULD REMAIN LIMITED ENOUGH FRIDAY AND FRIDAY NIGHT ACROSS THE AREA...AND CONFLUENT FLOW ALOFT WILL BE IN PLACE...SO ONLY A SLIGHT CHANCE OF RAIN AND SNOW IS INCLUDED IN THE FORECAST...MAINLY OVER THE SOUTHERN COUNTIES OF THE AREA. INCONSISTENCIES ACROSS THE MODELS HAVE BEEN MUCH MORE ABUNDANT WITH THE HANDLING OF THE UPPER LOW AS IT EMERGES INTO THE PLAINS STATES ON SATURDAY. AFTER SUGGESTING YESTERDAY THAT PHASING OF NORTHERN AND SOUTHERN STREAM ENERGY MAY NOT HAPPEN...RUNS LAST NIGHT AND TODAY ARE SUGGESTING THIS PHASING MAY INDEED OCCUR. THE 12Z RUNS HAVE ALL PRETTY MUCH COME IN SUPPORTING PHASING AND A SURFACE LOW TRACK INTO THE OHIO VALLEY AND GREAT LAKES FROM SATURDAY AFTERNOON THROUGH SUNDAY. THIS SOLUTION WOULD SUPPORT THE DEVELOPMENT OF A WINTRY MIX OF PRECIPITATION LATE FRIDAY NIGHT AND SATURDAY MORNING ACROSS THE AREA...BEFORE CHANGING OVER TO RAIN BY LATER SATURDAY AFTERNOON. BUFKIT SOUNDINGS INDICATE ENOUGH COLD AIR SHOULD INITIALLY BE IN PLACE AT THE SURFACE FOR SOME FREEZING RAIN TO DEVELOP LATE FRIDAY NIGHT AND SATURDAY MORNING WITH THIS PARTICULAR STORM TRACK. ONLY A MIX OF RAIN AND SNOW WILL BE INCLUDED IN THIS FORECAST PACKAGE FOR NOW...PENDING MORE AGREEMENT ON THE SYSTEM TRACK FROM FUTURE MODEL RUNS. RAIN MAY CHANGE BACK TO SOME SNOW AS PRECIPITATION PULLS OUT OF THE AREA SUNDAY...WITH TEMPERATURES COOLING BACK BELOW NORMAL. THE 12Z MODELS ARE TRYING TO RESOLVE A COUPLE OF DISTURBANCES ROTATING THROUGH CYCLONIC FLOW EARLY NEXT WEEK. THESE IMPULSES COULD BRING CHANCES FOR LIGHT SNOW TO THE AREA MONDAY AND TUESDAY. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... VFR SKC OR JUST FEW CLOUDS THROUGH 21-00Z...AND THEN BOTH RAP AND NAM PICK UP THE MVFR CIGS OVER INDIANA FAIRLY WELL AT THIS TIME...SO CONTINUING WITH THE PREVIOUS FORECAST OF MVFR CIGS IN THE 00Z-08Z TIMEFRAME...THOUGH THIS IS SLIGHTLY ON THE PESSIMISTIC SIDE AS ADVECTION OF MOISTURE OFF LAKE MI STOPPING OVERNIGHT AS THE SFC HIGH BUILDS IN AND THE MOISTURE FLOW CUTS OFF. SCATTERING/LIFING OF THE MVFR CLOUDS MAY OCCUR EARLIER. SOME POTENTIAL AT KDAY/KCMH/KLCK FOR MVFR CIGS TO DROP BELOW THE 2K FT FUEL ALTERNATE CRITERIA THRESHOLD IN THE 02Z-08Z TIMEFRAME. AFTER THIS LL MOISTURE PUSHES EAST...FLOW BACKS TO THE SW WITH SLIGHTLY INCREASED WINDS. OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE ON SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...JGL NEAR TERM...JGL SHORT TERM...JGL LONG TERM...SHOBE2 AVIATION...JDR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1256 PM EST TUE DEC 30 2014 .SYNOPSIS... HIGH PRESSURE WILL KEEP A DRY CONIDITIONS OVER THE OHIO VALLEY THROUGH FRIDAY. ON FRIDAY NIGHT...LOW PRESSURE FROM THE SOUTHERN PLAINS WILL TRACK TOWARD THE LOWER OHIO VALLEY AT THE SAME TIME A LOW PRESSURE WILL TRACK TOWARD THE GREAT LAKES FROM THE NORTHERN PLAINS. THE COMBINATION OF THESE TWO SYSTEMS WILL BRING PRECIPITATION TO THE REGION FRIDAY NIGHT INTO THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CONTINUED SUN...BUT WITH SOME LAKE EFFECT CLOUDS TO AFFECT THE NORTHERN FCST AREA AS THE AFTERNOON PROGRESSES. WITH THIS AMOUNT OF SUN...TEMPS IN ESPECIALLY THE SOUTHERN FCST AREA CLIMBING A BIT MORE THAN ANTICIPATED SO HAVE RAISED HIGHS SLIGHTLY HERE. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... HIGH PRESSURE WILL DIVE SOUTHWARD FROM THE NORTHERN PLAINS TODAY TO OKLAHOMA WEDNESDAY AND THEN SETTLE OVER THE GULF STATES THURSDAY. THE HIGH WILL THEN LIFT NORTHWARD THROUGH THE TENNESSEE VALLEY TO THE OHIO VALLEY BY FRIDAY EVENING. GENERALLY DRY CONDITIONS AND MOSTLY CLEAR SKIES WILL OCCUR FOR THE REGION THROUGH THIS TIME. THE ARCTIC AIR WILL BE AT ITS HEIGHT OVER THE REGION TONIGHT THROUGH WEDNESDAY NIGHT WITH LOWS IN THE TEENS AND HIGHS IN THE 20S. THE AIRMASS WILL BEGIN TO MODERATE AFTER THIS TIME WITH A GRADUAL RISE IN BOTH DAYTIME HIGHS AND NIGHTTIME LOWS FOR EACH PERIOD. THE NEXT SHOT OF PRECIPITATION WILL BEGIN LATE FRIDAY NIGHT AS A WARM FRONT PASSES OVER THE REGION ASSOCIATED WITH LOW PRESSURE EJECTING NORTHEAST FROM THE WESTERN GULF. && .LONG TERM /SATURDAY THROUGH MONDAY/... THE PERIOD BEGINS WITH SURFACE HIGH PRESSURE ACROSS THE LOWER MISSISSIPPI VALLEY THURSDAY AND THURSDAY NIGHT. THIS FEATURE WILL KEEP DRY CONDITIONS ACROSS THE AREA WITH BELOW NORMAL TEMPERATURES. THE MAIN QUESTION FOR THIS FORECAST CONTINUES TO BE THE EVOLUTION OF THE SOUTHWEST CONUS UPPER LOW. MODEL RUNS FROM THE PAST COUPLE DAYS HAVE GENERALLY SLOWED THE EJECTION OF THIS LOW...WITH THE FEATURE NOT REALLY LEAVING THE FOUR CORNERS ON THE 12Z RUNS UNTIL FRIDAY NIGHT. SOME MOISTURE IS SHOWN RETURNING FRIDAY FROM THE GULF TOWARD THE OHIO VALLEY WELL AHEAD OF THE UPPER LOW...THOUGH CONFLUENT FLOW ALOFT SHOULD COUNTERACT THE DEVELOPMENT OF PRECIPITATION ACROSS THE AREA. ENOUGH LIFT AND MOISTURE MAY BE IN PLACE BY FRIDAY NIGHT TO PRODUCE SOME RAIN AND SNOW...ESPECIALLY ACROSS THE SOUTHERN PORTION OF THE AREA. THAT CHANCE WILL CONTINUE INTO SATURDAY...THOUGH THE 12Z ECMWF/PARALLEL GFS ARE INDICATING THE BEST MOISTURE AND SURFACE LOW DEVELOPMENT WILL REMAIN SOUTH OF THE AREA. THE 12Z GFS AND GFS ENSEMBLE STILL SHOW THIS SYSTEM PROPAGATING TOWARD THE OHIO VALLEY...THOUGH THE STRENGTH OF THE UPPER LOW IN PLACE OVER HUDSON BAY MAY JUST BE ENOUGH TO BRUSH THIS SYSTEM MORE EAST ALONG THE LINES OF THE ECMWF/PARALLEL GFS. THIS SOLUTION WOULD STILL KEEP CHANCES OF RAIN AND SNOW ACROSS THE AREA THROUGH SUNDAY...THOUGH MORE FOCUSED ON THE THE SOUTHERN COUNTIES. ALL OF THE MODELS TEND TO PULL PRECIPITATION OUT OF THE AREA BY SUNDAY NIGHT...WITH GENERALLY DRY CONDITIONS IN PLACE MONDAY. TEMPERATURES SHOULD BE NEAR TO SOMEWHAT BELOW NORMAL AT THE END OF THE PERIOD. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... VFR SKC OR JUST FEW CLOUDS THROUGH 21-00Z...AND THEN BOTH RAP AND NAM PICK UP THE MVFR CIGS OVER INDIANA FAIRLY WELL AT THIS TIME...SO CONTINUING WITH THE PREVIOUS FORECAST OF MVFR CIGS IN THE 00Z-08Z TIMEFRAME...THOUGH THIS IS SLIGHTLY ON THE PESSIMISTIC SIDE AS ADVECTION OF MOISTURE OFF LAKE MI STOPPING OVERNIGHT AS THE SFC HIGH BUILDS IN AND THE MOISTURE FLOW CUTS OFF. SCATTERING/LIFING OF THE MVFR CLOUDS MAY OCCUR EARLIER. SOME POTENTIAL AT KDAY/KCMH/KLCK FOR MVFR CIGS TO DROP BELOW THE 2K FT FUEL ALTERNATE CRITERIA THRESHOLD IN THE 02Z-08Z TIMEFRAME. AFTER THIS LL MOISTURE PUSHES EAST...FLOW BACKS TO THE SW WITH SLIGHTLY INCREASED WINDS. OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE ON SATURDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...JDR NEAR TERM...JDR SHORT TERM...FRANKS LONG TERM...SHOBE2 AVIATION...JDR
AREA FORECAST DISCUSSION
NWS TULSA OK
1126 PM CST MON DEC 29 2014 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. VFR CIGS ALL SITES WITH LAYERED CLOUDS THROUGHOUT THE PERIOD. CIGS BECOMING MVFR NERN OK SITES FOLLOWING COLD FRONTAL SURGE LATER TONIGHT. CIGS PROBABLY HANG AROUND ON TUESDAY LONGER THAN INDICATED IN MODEL FIELDS. NORTHEASTERLY WIND WILL BACK TO THE NORTH NORTHEAST AND INCREASE WITH FRONTAL PASSAGE. && .PREV DISCUSSION... /ISSUED 904 PM CST MON DEC 29 2014/ ..UPDATE... DISCUSSION... RADAR ECHOES ARE LEAVING THE FORECAST AREA...SO WILL DROP MENTION OF FLURRIES FOR THE REMAINDER OF THE OVERNIGHT PERIOD. 00Z NAM...01Z HRRR AND 02Z RAP ALL APPEAR DRY FOR THE REST OF THE NIGHT. LFM IS MISSING...ALONG WITH BAROTROPIC AND SHIP PAPA DATA. ..HAVING A RIP VAN WINKLE MOMENT... WILL UPDATE TO TAKE OUT FLURRIES AND SPRINKLES. APPEARS THE COLD SURGE IS STILL IN KANSAS...FROM JUST SOUTH OF MKC TO NORTH OF ICT TO NEAR AMA...BASED MAINLY ON LOCATION OF STRONGEST WINDS AND GUSTINESS. PROGRESS HAS BEEN SLOW...BUT ON TARGET FOR TUESDAY MORNING. NO CHANGE TO MINIMUM TEMPS. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...02 AVIATION...69
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
333 AM EST TUE DEC 30 2014 .SYNOPSIS... A HIGHLY AMPLIFIED PATTERN OVER NORTH AMERICA WITH A STRONG RIDGE OVER THE PACIFIC NORTHWEST AND A TROUGH OVER THE NORTHEAST WILL PRODUCE TWO COLD SURGES. THE FIRST SHOULD PRODUCE COLD WEATHER TROUGH NEW YEARS. A SOUTHERN STREAM STORM COULD BRING A WINTRY MIX AND/OR RAIN TO THE REGION OVER THE WEEKEND AHEAD OF THE FORECAST SECOND SURGE OF COLD CONTINENTAL AIR. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SATELLITE IMAGERY CONTINUES TO SHOW TWO DISTINCT CLOUDS SYSTEMS...HIGH CLOUDS PASSING TO OUR SOUTH AND LOW CLOUDS NEAR THE NY BORDER. HRRR SHOWS NO SIGNIFICANT SNOW AREAS OVERNIGHT...HOWEVER LATESET RADAR IMAGERSY SHOWS BAND OF FLURRIES/LIGHT SNOW SHOWERS MOVING SE ACROSS PARTS OF THE CENTRAL MTNS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... THE HRRR ONLY GETS US TO LATE MORNING AND IT SHOWS...AT BEST SOME FLURRIES IN SPOTS ALONG NY BORDER IN MORNING. HIGH PRESSURE TO OUR WEST CONTINUES TO BUILD INTO THE REGION FROM THE WEST TUESDAY. IN THIS NORTH-NORTHWEST FLOW OUR 850 MB TEMPS FALL 2 TO 4 MORE DEGREES DURING THE DAY GETTING TO ABOUT -1SD BELOW NORMAL BY EVENING. A COLDER THAN NORMAL DAY IS ON TAP. THE HIGH SLIDES TO OUR SOUTH AND WEST INTO WEDNESDAY AND OUR 850 MB TEMPS BOTTOM OUT IN THE -13 TO -18C RANGE. THIS IMPLIES BETTER CHANCE OF SOME LAKE ENHANCED SNOWS IN NORTHWESTERN AND WESTERN MOUNTAINS. THE SNOW IN NW PA AND SW NY PEAKS IN THE SREF AFTER 00 TO 03 UTC WEDNESDAY AND BEGINS TO DIMINISH WEDNESDAY EVENING. TRIED TO SHOW SOME SNOW UP IN THE NW AREAS BUT KEPT AMOUNT ON THE LOW SIDE. BLENDED LARGE SCALE MODELS WITH 21Z SREF TO REFINE THE AREA OF POPS AND QPF. QPF AMOUNTS WERE OF COURSE LOW. CLEARLY WEDNESDAY SHOULD BE ABOUT THE COLDEST DAY OF THE WINTER TO DATE WITH THE -16C CONTOUR DRAPED OVER CENTRAL PA AND AT LEAST -1SD BELOW NORMAL TEMPERATURES. THAT IS 5 TO 10F BELOW NORMAL. THE COLD AT LEAST WILL CONTINUE INTO NEW YEARS DAY (SEE BELOW) AS THE HIGH LUMBERS BY TO OUR SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES AND PERHAPS SNOW IN NORTHERN AND SOME CENTRAL AREAS. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS OVERNIGHT. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/GARTNER NEAR TERM...GRUMM/GARTNER SHORT TERM...GRUMM LONG TERM...RXR AVIATION...DANGELO/CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
217 AM EST TUE DEC 30 2014 .SYNOPSIS... A HIGHLY AMPLIFIED PATTERN OVER NORTH AMERICA WITH A STRONG RIDGE OVER THE PACIFIC NORTHWEST AND A TROUGH OVER THE NORTHEAST WILL PRODUCE TWO COLD SURGES. THE FIRST SHOULD PRODUCE COLD WEATHER TROUGH NEW YEARS. A SOUTHERN STREAM STORM COULD BRING A WINTRY MIX AND/OR RAIN TO THE REGION OVER THE WEEKEND AHEAD OF THE FORECAST SECOND SURGE OF COLD CONTINENTAL AIR. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SATELLITE IMAGERY CONTINUES TO SHOW TWO DISTINCT CLOUDS SYSTEMS...HIGH CLOUDS PASSING TO OUR SOUTH AND LOW CLOUDS NEAR THE NY BORDER. HRRR SUGGESTS OUR FORECASTS IN SOUTH/CENTRAL ARE TOO CLOUDY. HRRR ALSO SHOWS NO SIGNIFICANT SNOW AREAS OVERNIGHT IN NORTHWEST. THE WEAK NORTHWEST FLOW OUT OF THE HIGH CENTERED OVER THE TN VALLEY DOES NOT CAUSE THE MODEL TO GENERATE ANY LAKE ENHANCED SNOWS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... THE HRRR ONLY GETS US TO LATE MORNING AND IT SHOWS...AT BEST SOME FLURRIES IN SPOTS ALONG NY BORDER IN MORNING. HIGH PRESSURE TO OUR WEST CONTINUES TO BUILD INTO THE REGION FROM THE WEST TUESDAY. IN THIS NORTH-NORTHWEST FLOW OUR 850 MB TEMPS FALL 2 TO 4 MORE DEGREES DURING THE DAY GETTING TO ABOUT -1SD BELOW NORMAL BY EVENING. A COLDER THAN NORMAL DAY IS ON TAP. THE HIGH SLIDES TO OUR SOUTH AND WEST INTO WEDNESDAY AND OUR 850 MB TEMPS BOTTOM OUT IN THE -13 TO -18C RANGE. THIS IMPLIES BETTER CHANCE OF SOME LAKE ENHANCED SNOWS IN NORTHWESTERN AND WESTERN MOUNTAINS. THE SNOW IN NW PA AND SW NY PEAKS IN THE SREF AFTER 00 TO 03 UTC WEDNESDAY AND BEGINS TO DIMINISH WEDNESDAY EVENING. TRIED TO SHOW SOME SNOW UP IN THE NW AREAS BUT KEPT AMOUNT ON THE LOW SIDE. BLENDED LARGE SCALE MODELS WITH 21Z SREF TO REFINE THE AREA OF POPS AND QPF. QPF AMOUNTS WERE OF COURSE LOW. CLEARLY WEDNESDAY SHOULD BE ABOUT THE COLDEST DAY OF THE WINTER TO DATE WITH THE -16C CONTOUR DRAPED OVER CENTRAL PA AND AT LEAST -1SD BELOW NORMAL TEMPERATURES. THAT IS 5 TO 10F BELOW NORMAL. THE COLD AT LEAST WILL CONTINUE INTO NEW YEARS DAY (SEE BELOW) AS THE HIGH LUMBERS BY TO OUR SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES AND PERHAPS SNOW IN NORTHERN AND SOME CENTRAL AREAS. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS OVERNIGHT. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/GARTNER NEAR TERM...GRUMM/GARTNER SHORT TERM...GRUMM LONG TERM...RXR AVIATION...DANGELO/CERU/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
109 AM EST TUE DEC 30 2014 .SYNOPSIS... A HIGHLY AMPLIFIED PATTERN OVER NORTH AMERICA WITH A STRONG RIDGE OVER THE PACIFIC NORTHWEST AND A TROUGH OVER THE NORTHEAST WILL PRODUCE TWO COLD SURGES. THE FIRST SHOULD PRODUCE COLD WEATHER TROUGH NEW YEARS. A SOUTHERN STREAM STORM COULD BRING A WINTRY MIX AND/OR RAIN TO THE REGION OVER THE WEEKEND AHEAD OF THE FORECAST SECOND SURGE OF COLD CONTINENTAL AIR. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... SATELLITE IMAGERY CONTINUES TO SHOW TWO DISTINCT CLOUDS SYSTEMS...HIGH CLOUDS PASSING TO OUR SOUTH AND LOW CLOUDS NEAR THE NY BORDER. HRRR SUGGESTS OUR FORECASTS IN SOUTH/CENTRAL ARE TOO CLOUDY. HRRR ALSO SHOWS NO SIGNIFICANT SNOW AREAS OVERNIGHT IN NORTHWEST. THE WEAK NORTHWEST FLOW OUT OF THE HIGH CENTERED OVER THE TN VALLEY DOES NOT CAUSE THE MODEL TO GENERATE ANY LAKE ENHANCED SNOWS. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/... THE HRRR ONLY GETS US TO LATE MORNING AND IT SHOWS...AT BEST SOME FLURRIES IN SPOTS ALONG NY BORDER IN MORNING. HIGH PRESSURE TO OUR WEST CONTINUES TO BUILD INTO THE REGION FROM THE WEST TUESDAY. IN THIS NORTH-NORTHWEST FLOW OUR 850 MB TEMPS FALL 2 TO 4 MORE DEGREES DURING THE DAY GETTING TO ABOUT -1SD BELOW NORMAL BY EVENING. A COLDER THAN NORMAL DAY IS ON TAP. THE HIGH SLIDES TO OUR SOUTH AND WEST INTO WEDNESDAY AND OUR 850 MB TEMPS BOTTOM OUT IN THE -13 TO -18C RANGE. THIS IMPLIES BETTER CHANCE OF SOME LAKE ENHANCED SNOWS IN NORTHWESTERN AND WESTERN MOUNTAINS. THE SNOW IN NW PA AND SW NY PEAKS IN THE SREF AFTER 00 TO 03 UTC WEDNESDAY AND BEGINS TO DIMINISH WEDNESDAY EVENING. TRIED TO SHOW SOME SNOW UP IN THE NW AREAS BUT KEPT AMOUNT ON THE LOW SIDE. BLENDED LARGE SCALE MODELS WITH 21Z SREF TO REFINE THE AREA OF POPS AND QPF. QPF AMOUNTS WERE OF COURSE LOW. CLEARLY WEDNESDAY SHOULD BE ABOUT THE COLDEST DAY OF THE WINTER TO DATE WITH THE -16C CONTOUR DRAPED OVER CENTRAL PA AND AT LEAST -1SD BELOW NORMAL TEMPERATURES. THAT IS 5 TO 10F BELOW NORMAL. THE COLD AT LEAST WILL CONTINUE INTO NEW YEARS DAY (SEE BELOW) AS THE HIGH LUMBERS BY TO OUR SOUTH. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... STRONG HIGH PRESSURE OVER THE CENTRAL U.S. THIS MIDWEEK WILL WEAKEN AND DRIFT TOWARD THE CAROLINAS BY FRIDAY AS A WEAK WAVE SLIDES QUICKLY ACROSS THE GREAT LAKES. THIS WILL BRING AN EXTENDED PERIOD OF FAIR BUT COOLER THAN NORMAL WEATHER TO THE FORECAST AREA. SOME SNOW SHOWERS MAY IMPACT THE NW MTNS...BUT MOST OF THE SNOW SHOWER ACTIVITY WILL REMAIN NORTH OF THE PA BORDER. BREEZY CONDITIONS WED NIGHT INTO THU IN FAST FLOW WILL RESULT IN SINGLE DIGIT WIND CHILLS OVER NORTHERN AND WESTERN PARTS OF THE CWA AS WE RING IN THE NEW YEAR. GEFS AND OTHER LONG RANGE GUIDANCE SHOW THE FIRST NOTABLE STORM OF 2015 DEVELOPING FOR NEXT WEEKEND. TIMING/STORM TRACK ISSUES REMAIN WITH MUCH UNCERTAINTY IN EVOLUTION OF THIS SYSTEM...BUT GUIDANCE IMPLIES A POTENTIAL MIXED PRECIPITATION EVENT FROM GENERALLY SAT AFT THROUGH FIRST HALF OF SUNDAY. GFS CONTINUES TO BRINGS A LOW UP THE OHIO VALLEY TO OUR WEST...PUSHING A SHOT OF MILDER AIR BACK INTO THE STATE WITH RAIN LIKELY BECOMING THE MOST DOMINANT PRECIPITATION TYPE /WITH FREEZING PRECIP POSS AT ONSET/. IN CONTRAST...THE OPERATIONAL ECMWF REMAINING FIRM ON BRINGING THE SURFACE LOW SOUTH AND EAST OF PA WHICH WOULD RESULT IN COLDER AIR AND A MORE MIXED BAG OF PRECIPITATION TYPES AND PERHAPS SNOW IN NORTHERN AND SOME CENTRAL AREAS. THE EC MEAN IS A BIT MORE AGGRESSIVE DEVELOPING THE LOW...POTENTIALLY MAKING THE OPERATIONAL RUN AN OUTLIER. FOR NOW...DIDN/T MAKE ANY LARGE CHANGES TO FORECAST OVER THE WEEKEND AND HELD ON TO THE POTENTIAL FOR A MIX OF WINTRY PRECIP - ESP ACROSS CENTRAL AND NORTHERN PA...AND LEANED MORE TOWARD RAIN IN THE LOWER SUSQ. QUICK SHOT OF COLDER AIR TO START NEXT WEEK...WITH CHANCE FOR ANOTHER LOW SLIDING EASTWARD FROM THE GREAT LAKES INTO NEW ENGLAND MIDWEEK WITH CHANCE OF SNOW FOR PA. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... MVFR CIGS WILL LIKELY REMAIN IN PLACE AT BFD INTO TUESDAY WITH NORTHWESTERLY WINDS AND A CHILLY...SHALLOW AIR MASS. CONTINUED NORTHWESTERLY FLOW WILL MAKE A FEW FLURRIES AT BFD...BUT THE REST OF THE TERMINALS WILL REMAIN DRY AND ONLY JST MAY SEE MVFR CIGS OVERNIGHT. CLOUDS MAY LOWER AT IPT/UNV AS THE LOW CLOUD DECK ASSOCIATED WITH THE COLDER AIR SLIDING DOWN FROM THE NORTH MOVES SOUTHWARD. BUT...WILL KEEP IT AS VFR THRU THE TAF PERIOD FOR THE TIME BEING. HIGH PRESSURE CENTERED OVER THE FRONT RANGE OF THE ROCKIES AND THE GREAT PLAINS WILL STRETCH FAR TO THE EAST AND GRADUALLY SINK SOUTHWARD. A BRIEF SHOT OF COLDER AIR WITHIN A FEW HOURS OF 12Z WED MAY CREATE A BROADER AREA OF SHSN/SQ. BUT THE REDUCTIONS IN VIS/CIG SHOULD BE LIMITED TO BFD...AND NOT EVEN JST. THE WAVE ALOFT WILL BE ACCOMPANIED BY VERY LITTLE MOISTURE. WINDS COULD BECOME GUSTY...THOUGH. OUTLOOK... WED-FRI...VFR. SAT...MVFR/IFR POSS IN WINTRY PRECIP. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...GRUMM/GARTNER NEAR TERM...GRUMM/GARTNER SHORT TERM...GRUMM LONG TERM...RXR AVIATION...DANGELO/GARTNER
AREA FORECAST DISCUSSION
NWS EL PASO TX/SANTA TERESA NM
258 PM MST TUE DEC 30 2014 .SYNOPSIS... A COLD FRONT PUSHED WEST ACROSS MUCH OF THE BORDERLAND TODAY... LEAVING IN IT`S WAKE COLD AIR AND INCREASING LOW CLOUDS FOR TONIGHT. A PACIFIC FRONTAL SYSTEM WILL MOVE TO WESTERN ARIZONA WEDNESDAY. THIS WILL PUSH CLOUDS IN AND KICK OFF SNOW SHOWERS OVER THE GILA AND RAIN SHOWERS OVER THE LOWLANDS. MOST OF THIS ACTIVITY WILL END THURSDAY FOR A BRIEF PERIOD BEFORE THE MAIN UPPER LOW MOVES OVER THE AREA FRIDAY. THIS WILL SPREAD MORE RAIN AND SNOW SHOWERS...WITH THE SACRAMENTO MOUNTAINS LIKELY SEEING HEAVY SNOW. MUCH OF THE LOWLANDS COULD SEE A MIX OF RAIN AND SNOW BUT LITTLE OR NO ACCUMULATION. THE LOW EXITS THE AREA FRIDAY NIGHT ALLOWING SKIES TO CLEAR. THROUGH MID WEEK OF NEXT WEEK...THE PATTERN LOOKS TO REMAIN A DRY WITH TEMPERATURES POSSIBLY BACK ABOVE NORMAL BY MONDAY. && .DISCUSSION... COMPLEX WINTER WEATHER PATTERN TO CONTINUE OVER THE NEXT 3 DAYS. MODELS HAVE BEEN RELATIVELY CLOSE...BUT 12Z GFS RUN THROUGH SOME DOUBT INTO FRIDAY SOLUTION. OTHERWISE FEW CHANGES MADE TO PREVIOUS FORECAST PACKAGE. BACK DOOR COLD FRONT SWEPT THROUGH THE RIO GRANDE VALLEY THIS MORNING. SFC OBS SHOW FRONT MAYBE OUT TO THE ARIZONA BORDER. COOL AIR LIKELY SHALLOW FROM DEMING WEST AS THOSE LOCATIONS WERE STILL ABLE TO MODIFY THIS AFTERNOON. EXTENSIVE LOW CLOUDS HAVE BEEN DAMMED UP AGAINST EASTERN TERRAIN ALL DAY. CLOUDS COVERED THE EASTERN SACS AND ARE SLOWLY SEEPING INTO HUDSPETH COUNTY. SOME FREEZING FOG HAS BEEN REPORTED...BUT PROG SOUNDINGS SUPPORT VERY LITTLE IN THE WAY OF PRECIP OVERNIGHT. WILL KEEP FREEZING FOG ADV OUT FOR EASTERN SACS AND ALSO ADD HUDSPETH COUNTY TO THE ADVISORY. TYPICAL PATTERN IS FOR LOW CLOUDS TO ACCELERATE WESTWARD AFTER SUNSET. HRRR ALSO SHOWS THIS...CLOUDING EL PASO CO OVER AROUND 6-7 PM...AND MOST OF THE REST OF THE LOWLANDS TO THE DIVIDE BY AROUND MIDNIGHT. LOW CLOUDS AND EAST PUSH WILL SLOWLY DIMINISH WEDNESDAY AS MAIN UPPER LOW DESCENDS DOWN TO WESTERN ARIZONA AND SURFACE GRADIENT BEGINS TO RELAX. NOT EXPECTING MUCH OF ANY PRECIP WEDNESDAY THOUGH KEEPING LOW POPS IN SEEMS PRUDENT. PACIFIC UPPER LOW AND SURFACE FRONT CONTINUE ADVANCING EAST. UPPER LOW PROGGED OVER EASTERN ARIZONA THURSDAY MORNING...WITH ATTENDANT FRONT PUSHING EAST ACROSS THE CWA. THIS WILL PRODUCE ANOTHER PERIOD SHOWERS...WITH SNOW LEVELS MOSTLY ABOVE 5000 FT. WILL ISSUED WINTER WEATHER ADV FOR THE GILA ZONES AS THIS SYSTEM LIKELY TO DROP DECENT SNOWFALL OVER THAT AREA. SHOULD SEE BRIEF END TO PRECIP THURSDAY NIGHT AS UPPER LOW LIFTS INTO COLORADO AND FRONT IS EAST OF THE AREA. HANG BACK LOW FORMS SOUTHWEST OF ORIGINAL LOW AND WILL MOVE OVER SOUTHERN NEW MEXICO FRIDAY. THIS IS WHERE THE 12Z GFS RUN DEVIATES FROM THE OTHER MODELS. NAM/ECMWF STILL SHOWING STRONG PRESENCE OF THIS LOW WITH HEAVY SNOW OVER THE SACS AND RAIN/SNOW OVER THE LOWLANDS. WILL STILL KEEP THIS THINKING FOR NOW. SNOW LEVELS FRIDAY LIKELY AT 4500-5000 FT SO SOME OF THE LOWLANDS COULD GET LIGHT SNOW ACCUMULATIONS. MOST FAVORED AREA NORTH AND WEST OF LAS CRUCES WILL HAVE TO BE WATCHED FOR POTENTIAL ADVISORIES. BELIEVE THE SACS WILL GET HEAVY SNOW BUT TOO EARLY TO ISSUE AT THIS TIME...ESPECIALLY WITH THE GFS UNCERTAINTY. UPPER LOW EXITS FRIDAY NIGHT WITH CLEARING TO FOLLOW. SATURDAY THROUGH TUESDAY PERIOD SHOULD REMAIN DRY AS WEST COAST UPPER RIDGE PERSISTS. TEMPERATURES SHOULD SLOWLY WARM BACK TO NORMAL BY MONDAY AND TUESDAY. && .AVIATION...VALID 31/00Z-01/00Z... THRU 06Z...P6SM FEW-SCT020 SCT-BKN150-200. AFT 06Z MOISTURE WILL BE PUSHING WESTWARD WITH SCT-BKN010-020 BKN-OVC120-150 DEVELOPING AT ALL TAF SITES WITH VERY PATCHY FZDZ POSSIBLE...MAINLY EAST OF KELP AND POSSIBLY TOWARD KTCS. LOW CLOUDS WILL REMAIN IN PLACE EAST OF RIO GRANDE...BUT POSSIBLY BECOME MORE SCT AFT 18Z WEST OF RIVER. E TO NE WINDS 10-20G30KTS THRU PD...STRONGEST ON WESTERN MOUNTAIN SLOPES. && .FIRE WEATHER... COLD FRONT HAS MOVED THROUGH THE REGION WITH GUSTY EAST WINDS IN PLACE WHICH WILL CONTINUE THROUGH WEDNESDAY. VERY LIGHT PRECIPITATION IN THE FORM OF FREEZING DRIZZLE IS POSSIBLE FAR NORTH AND EAST TONIGHT...BUT DEEPER LOW LEVEL MOISTURE WILL BE PUSHING WEST THROUGH THE NIGHT. SNOW IS EXPECTED OVER THE GILA REGION STARTING WEDNESDAY NIGHT AND OVER THE SACS MAINLY LATE THURSDAY INTO FRIDAY. SEVERAL INCHES OF SNOW ARE POSSIBLE IN EACH OF THESE MOUNTAIN ZONES. LOWLANDS COULD SEE A MIX OF RAIN AND SNOW WITH ANY ACCUMULATIONS REMAINING UNDER AN INCH. EXPECT BELOW NORMAL TEMPERATURES TO REMAIN IN PLACE THROUGH THE WEEKEND BEFORE WARMER AIR RETURNS EARLY NEXT WEEK. && .PRELIMINARY POINT TEMPS/POPS... EL PASO 29 43 35 50 31 / 0 0 10 20 20 SIERRA BLANCA 24 36 29 46 30 / 20 20 10 20 20 LAS CRUCES 26 42 31 46 30 / 0 0 10 30 30 ALAMOGORDO 25 42 31 48 29 / 20 0 20 20 30 CLOUDCROFT 20 33 22 36 23 / 30 20 20 40 50 TRUTH OR CONSEQUENCES 25 42 30 42 26 / 10 20 30 30 30 SILVER CITY 25 41 28 37 25 / 0 10 50 50 30 DEMING 27 44 30 44 27 / 0 0 20 30 30 LORDSBURG 28 45 31 43 26 / 0 10 40 40 20 WEST EL PASO METRO 30 43 36 48 35 / 0 0 10 20 20 DELL CITY 22 33 28 45 25 / 20 20 20 20 20 FORT HANCOCK 26 41 33 51 29 / 10 10 10 10 20 LOMA LINDA 24 38 29 45 32 / 20 10 10 20 30 FABENS 27 42 34 49 29 / 0 0 10 20 20 SANTA TERESA 26 44 32 48 30 / 0 0 10 20 20 WHITE SANDS HQ 27 40 33 46 32 / 0 0 10 20 30 JORNADA RANGE 21 43 25 45 25 / 0 0 10 30 30 HATCH 25 44 30 46 28 / 0 10 20 30 30 COLUMBUS 30 45 34 45 32 / 0 0 10 30 20 OROGRANDE 25 40 30 46 30 / 10 0 10 20 30 MAYHILL 18 30 22 38 26 / 50 30 30 40 30 MESCALERO 18 34 22 40 24 / 30 20 20 40 50 TIMBERON 20 33 22 38 25 / 20 20 20 40 40 WINSTON 22 39 24 39 21 / 20 20 50 60 30 HILLSBORO 25 42 28 41 26 / 10 20 30 40 30 SPACEPORT 21 44 25 45 24 / 0 10 20 30 30 LAKE ROBERTS 24 42 25 37 24 / 0 20 60 70 30 HURLEY 25 42 28 40 26 / 0 10 40 40 20 CLIFF 22 47 31 40 20 / 0 10 70 60 20 MULE CREEK 19 46 24 38 17 / 0 10 80 70 30 FAYWOOD 27 41 30 40 28 / 0 10 30 40 30 ANIMAS 30 50 34 47 28 / 0 0 40 30 20 HACHITA 26 46 29 45 26 / 0 0 30 30 20 ANTELOPE WELLS 29 53 33 50 28 / 0 0 20 30 20 CLOVERDALE 32 55 34 46 27 / 0 0 40 40 30 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...FREEZING FOG ADVISORY FROM 7 PM THIS EVENING TO 11 AM MST WEDNESDAY FOR NMZ417. WINTER WEATHER ADVISORY FROM 6 PM WEDNESDAY TO 11 AM MST THURSDAY FOR NMZ401>403-408. WIND ADVISORY UNTIL 11 AM MST WEDNESDAY FOR NMZ411. FREEZING FOG ADVISORY UNTIL 11 AM MST WEDNESDAY FOR NMZ416. TX...FREEZING FOG ADVISORY FROM 7 PM THIS EVENING TO 11 AM MST WEDNESDAY FOR TXZ420>424. WIND ADVISORY UNTIL 11 AM MST WEDNESDAY FOR TXZ418. && $$ HEFNER/GRZYWACZ
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1216 PM CST TUE DEC 30 2014 .UPDATE... COLDER AND SOMEWHAT DRIER AIR BEHIND THE ARCTIC COLD FRONT THAT PASSED ABOUT MID MORNING. WINDS ALSO SLIGHTLY MORE NORTHERLY. PRECIPITATION REMAINS LIGHT BUT ENOUGH FOR A LIGHT GLAZE ALMOST EVERYWHERE...AND LATELY OVER SOUTHERN PART OF THE ROLLING PLAINS. WIND CHILLS HAVE REMAINED BELOW MINUS 5 ACROSS NORTHWEST ZONES WITH WINDS ONLY SLIGHTLY LOWER WHILE TEMPERATURES UNLIKELY TO RISE THIS AFTERNOON. WE HAVE ADDED THE SOUTHERN PART OF THE ROLLING PLAINS TO THE WINTER WEATHER ADVISORY NOW UNTIL 3 PM. ALSO ISSUED A WIND CHILL ADVISORY FOR THE NORTHWEST UNTIL 3. MOST SOLUTIONS CONTINUE TO GENERATE LIGHT PRECIPITATION TONIGHT PERHAPS SLIGHTLY FAVORING SOUTHEAST ZONES BUT NOT CLEAR YET. RMCQUEEN && .AVIATION... WITH DRIER COLDER AIR MOVING IN WE EXPECT CEILINGS TO INCH BACK TO NEAR LOWER END OF MVFR CEILINGS LATER TODAY. SOLUTIONS STILL SUGGEST LOWERING CONDITIONS MAY BECOME PERVASIVE OVERNIGHT WITH EXPANDING LIGHT PRECIPITATION FOR KLBB AND KPVW BUT NOT CERTAIN ENOUGH EITHER FOR A CHANGE OR TEMPO GROUP. RMCQUEEN && .PREV DISCUSSION... /ISSUED 921 AM CST TUE DEC 30 2014/ UPDATE... ISSUED A WINTER WEATHER ADVISORY FOR FREEZING DRIZZLE ON THE CAPROCK UNTIL NOON. MAY NEED TO EXTEND THIS AFTERNOON...AND IF SO WILL CONSIDER GOING THROUGH MUCH OF THE NIGHT. VERY COLD AIR MOVING SOUTHWARD SHOULD CHANGE FREEZING DRIZZLE MORE TO LIGHT SNOW AND PERHAPS LESS ICE ACCUMULATIONS BUT NOT CERTAIN AT THIS TIME. RMCQUEEN PREV DISCUSSION... /ISSUED 544 AM CST TUE DEC 30 2014/ UPDATE... KLBB 88D SHOWING THE EXPANSION OF VERY LIGHT REFLECTIVTY /ZERO TO MINUS 15 DBZ/ BTWN 1000 AND 5000 FT AGL AND LOWERING WITH TIME. THIS SHOULD BE THE PERIOD OF VERY LIGHT FLURRIES AND/OR FREEZING DRIZZLE ASSOCIATED WITH FRONTOGENTICAL FORCING. PER THE HRRR THIS PRECIP SHOULD SHIFT SWD WITH THE FORCING THROUGH THE MORNING. EXPECTATION IS IT SHOULD REMAIN TOO LIGHT CAUSE MUCH IN THE WAY OF DIFFICULTY THIS MORNING...BUT WILL CONTINUE TO MONITOR TRENDS. AVIATION... CIGS TO LOWER A BIT MORE DURING THE FIRST PART OF THE FCST PERIOD BUT SHOULD REMAIN MVFR THEN REMAIN PRETTY STABLE THROUGH THE REMAINDER OF THE PERIOD. ANTICIPATE SOME PERIODS OF LIGHT FREEZING DRIZZLE AND/OR FLURRIES THROUGH THE FCST TIME AS WELL. GUSTY NNE WINDS THROUGH MUCH OF THE DAY SHOULD RELAX TOWARD EVENING. PREV DISCUSSION... /ISSUED 428 AM CST TUE DEC 30 2014/ SHORT TERM... THE COLD FRONT IS NOW WELL INTO THE PERMIAN BASIN AND BIG COUNTRY WITH MUCH COLDER AIR FILTERING IN BEHIND IT RATHER THAN SURGING AT THIS POINT. WITH A GOOD STRATUS DECK NOW IN PLACE...ALTHOUGH NOT TERRIBLY LOW AT ABOUT 2000 FT AGL...AND LOW LEVEL COLD ADVECTION PERSISTING THROUGH THE DAY...TEMPS WILL HAVE TROUBLE MOVING OFF OF MORNING LOWS. INDEED...WILL LIKELY SEE TEMPS FALL THROUGH ABOUT MID-MORNING BEFORE SOME SLIGHT RECOVERY LATER IN THE DAY. HOWEVER...MAIN FOCUS CONTINUES TO BE ON CHANCE FOR VERY LIGHT PRECIPITATION TODAY AND TONIGHT AND POTENTIAL IMPACTS OF IT WITH TEMPS IN THE TEENS AND 20S. THIS PRECIP EVENT CONTINUES TO LOOK PRIMARILY ISENTROPIC DRIVEN WITH SOME MINOR CONTRIBUTION FROM FRONTOGENETICAL FORCING EARLY ON. ISENTROPIC PROJECTIONS DEPICT LIFT INITIALLY AT THE VERY TOP OF THE COLD AIR...PRIMARILY IN THE WARMER AND DRIER MID LEVELS ABOVE IT. HOWEVER...AS THE COLD AIR DEEPENS THROUGH THE DAY...SOME OF THIS COLD MOISTURE SHOULD BE TAPPED BY THE ISENTROPIC LIFT TO PRODUCE SOME LIGHT PRECIP. BEST WINDOW FOR THIS APPEARS TO BE BETWEEN 3 PM AND MIDNIGHT...AFTER WHICH ISENTROPIC LIFT WEAKENS SIGNIFICANTLY. QUESTION THEN BECOMES PHASE OF THIS PRECIPITATION. PROGGED SOUNDINGS SUPPORT EITHER FREEZING DRIZZLE OR VERY LIGHT SNOW. COLDER LOW LEVELS ACROSS THE NORTH AND WEST MIGHT END UP FAVORING FLURRIES TO A DUSTING OF SNOW WHILE FURTHER SOUTH AND EAST FREEZING DRIZZLE LIKELY TO BE PREDOMINANT. HOW MUCH IS A BIG QUESTION WITH SOUNDINGS SUGGESTING THE MODEL QPF OUTPUT IS OVERDONE. AS FOR POTENTIAL FOR ADVISORY...STILL SOME DETAILS TO WORK OUT SUCH AS FLURRIES VS DRIZZLE AND TIMING OF ONSET OF PRECIP HEAVY AND/OR WIDESPREAD ENOUGH TO BEGIN TO CAUSE TRAVEL ISSUES. SINCE CURRENT EXPECTATION IS THE MORE SIGNIFICANT PART OF THE EVENT IS STILL 8-12 HOURS AWAY AND ANOTHER MODEL RUN AND 12Z UA ANALYSIS SHOULD HELP NARROW DOWN THE DETAILS FURTHER...WILL DEFER ON THE ISSUANCE OF AN ADVISORY ATTM. LONG TERM... AN UA DISTURBANCE ACROSS THE GREAT BASIN IS STILL PROGGED TO PINCH OFF AND DIVE SSE TO ACROSS SRN CALI TOMORROW...AND ACROSS THE DESERT SW ON THURSDAY. AS SUCH...FLOW ALOFT WILL EVOLVE FROM A BROAD CYCLONIC FLOW TO SWRLY FLOW. IF THE ANTICIPATED TRACK OF THE SYSTEM DOES NOT CHANGE...IT WILL MOVE DIRECTLY ACROSS THE SOUTHERN PLAINS FRIDAY NIGHT THEN EXIT TO THE NE BY SATURDAY. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL. TEMPS STRUGGLING TO GET OUT OF THE 20S WILL CHARACTERIZE WEDNESDAY AS THE CAA USHERED IN BY LAST NIGHT/S COLD FRONTAL PASSAGE REMAINS ENTRENCHED. FURTHERMORE...MAY ALSO EXPERIENCE A LINGERING FREEZING DRIZZLE/WINTRY MIX...COURTESY OF MOISTENED ATMOSPHERIC LOW LEVELS AND AN UPSLOPE SFC REGIME. THIS WINTRY MIX MAY BE HARD-PRESSED TO REACH THE GROUND AS IT WILL HAVE TO FALL THROUGH RATHER DRY MID-LEVELS...WHICH IS WHERE THE SLIVER OF UL SUPPORT IS MAXIMIZED. ON THURSDAY DURING THE DAY...A SIMILAR SCENARIO TO WEDNESDAY WILL PLAY OUT...WITH THE DIFFERENCE BEING PROGGED MODEL SOUNDINGS HINTING AT A WARM TONGUE DEVELOPING IN THE MID-LEVELS...THUS SUGGESTING MORE OF A FREEZING RAIN/WINTRY MIX OCCURRENCE. NONETHELESS...THE BEST LIFT IS STILL MAXIMIZED WITHIN THE DRY MID-LEVELS AND HENCE LIGHT PRECIP IS EXPECTED. BY THURSDAY NIGHT HOWEVER...MID-LEVELS ARE SHOWN TO MOISTEN AS THE UA SYSTEM DRAWS NEAR. THE BEST UL SUPPORT IS FINALLY TAPPING INTO ADEQUATE MOISTURE. MID-LEVEL MOISTENING OCCURRING WITHIN THE DENDRITIC ZONE COULD PROMOTE A CHANCE OF SNOW...PARTICULARLY ACROSS THE HIGHER TERRAIN OF THE NWRN ZONES. ELSEWHERE...FREEZING RAIN AND PERHAPS SLEET WILL BE COMMON...WITH THE EXCEPTION OF THE FAR ROLLING PLAINS WHERE A MIX OF A COLD RAIN AND FREEZING RAIN MAY OCCUR...GIVEN TEMPS WILL WARM TO SLIGHTLY ABOVE FREEZING THERE /LOWER 30S ELSEWHERE/. TEMPS WILL WARMUP FURTHER ON FRIDAY...INTO THE MIDDLE TO UPPER 30S ON THE CAPROCK TO UPPER 30S TO LOWER 40S OFF THE CAPROCK...WHICH WILL AFFECT THE PRECIP PHASE. COULD THEREFORE SEE MORE OF A RAIN AND SNOW MIX OR A RAIN AND FREEZING RAIN MIX DEVELOP BY THE EVENING /THE NWRN ZONES WILL BE THE EXCEPTION AS SOUNDING PROFILES SUGGEST LIGHT SNOW THERE/. LATE FRIDAY NIGHT-EARLY SATURDAY MORNING...LARGE SCALE ASCENT WILL BE FLEETING AS THE SYSTEM COMMENCE TO EXIT THE REGION. PERHAPS SOME LINGERING RAIN AND SNOW MIX WILL BE POSSIBLE ACROSS PORTIONS OF THE ROLLING PLAINS EARLY SATURDAY MORNING. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL AND THE RETURN TO SRLY SFC FLOW EARLY NEXT WEEK WILL AID IN PUSHING TEMPS BACK UP TO NEAR 50. NOTE: ALTHOUGH THE WINTRY PRECIP IS EXPECTED TO BE LIGHT THIS WEEK...IT COULD STILL POSE A THREAT FOR HAZARDOUS ROAD CONDITIONS AS A THIN GLAZE OF ICE COULD FORM ACROSS OVERPASSES AND BRIDGES IN PARTICULAR. AS YOU HEAD OUT TO ENJOY THE NEW YEAR FESTIVITIES...CAUTION IS ADVISED. CHECK BACK TO STAY ALERT AND UP TO DATE WITH ANY WEATHER CHANGES. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 7 22 17 32 20 / 40 20 10 20 20 TULIA 10 22 19 32 23 / 40 10 10 20 20 PLAINVIEW 12 23 19 32 25 / 40 10 10 20 20 LEVELLAND 14 24 19 32 25 / 50 20 20 20 30 LUBBOCK 14 25 21 32 26 / 50 20 20 20 30 DENVER CITY 16 25 20 33 26 / 50 20 20 30 30 BROWNFIELD 15 25 20 33 26 / 50 20 20 30 30 CHILDRESS 14 25 22 34 26 / 40 10 10 20 30 SPUR 15 25 22 33 27 / 50 20 20 30 30 ASPERMONT 18 27 24 36 29 / 40 20 20 30 30 && .LUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ021>024-027>030-033>037-039>044. WIND CHILL ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: TXZ021>023. && $$ 05/99/05
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1006 AM CST TUE DEC 30 2014 .UPDATE... WITH FOG BEGINNING TO LIFT IN MANY AREAS EAST OF THE I35 CORRIDOR...ALLOWED THE DENSE FOG ADVISORY TO EXPIRE OUT THERE. HOWEVER...FOG IS SLUGGISH TO LIFT ON THE ESCARPMENT AND SOME LOCATIONS IN THE EASTERN PARTS OF THE I35 CORRIDOR COUNTIES ARE STILL SEEING VISIBILITIES RISE AND FALL. EXPECT THIS TO IMPROVE OVER THE NEXT TWO HOURS SO EXTENDED THE DFA THROUGH 18Z TO BE SAFE. TB3 && .PREV DISCUSSION... /ISSUED 725 AM CST TUE DEC 30 2014/ UPDATE...ONE FINAL UPDATE TO EXPAND DENSE FOG ADVISORY WEST TO THE RIO GRANDE. PREV DISCUSSION... /ISSUED 613 AM CST TUE DEC 30 2014/ AVIATION... LIFR/VLIFR VIS AND CIGS IN AUSTIN AND SAN ANTONIO THIS MORNING WILL CONTINUE UNTIL MID-MORNING WHEN NORTHWESTERLY WINDS PICK UP. THEN MVFR/IFR CIGS THROUGH THE REST OF THE TAF PERIOD. DRT WILL DROP TO IFR SHORTLY AND STAY THAT WAY UNTIL AROUND 18Z. EXPECTING PRECIPITATION WEDNESDAY MORNING AT DRT. HAVE NOT INCLUDED ANY PRECIP IN AUSTIN OR SAN ANTONIO...BUT THERE IS A SLIGHT CHANCE FOR RAIN. IF THERE IS ANY RAIN IT WILL DROP VIS TO MVFR. PREV DISCUSSION... /ISSUED 523 AM CST TUE DEC 30 2014/ UPDATE...SECOND UPDATE TO EXPAND DENSE FOG ADVISORY FARTHER WEST AND SOUTH BASED ON SATELLITE AND WEB CAM TRENDS. THIS ALSO LINES UP WELL WITH HRRR EXPANSION OF FOG. PREV DISCUSSION... /ISSUED 443 AM CST TUE DEC 30 2014/ UPDATE...QUICK UPDATE TO ISSUE DENSE FOG ADVISORY FOR I-35 CORRIDOR FROM COMAL TO WILLIAMSON COUNTY EASTWARD. THIS IS BASED ON SEVERAL WEBCAMS AND OBS INDICATING DENSE FOG. THERE IS ALSO THE POTENTIAL FOR PATCHY TO AREAS OF DENSE FOG SOUTH AND WEST OF THE ADVISORY AREA THROUGH THE MORNING. PREV DISCUSSION... /ISSUED 401 AM CST TUE DEC 30 2014/ SHORT TERM (TODAY THROUGH WEDNESDAY)...AREAS OF LOW STRATUS AND FOG HAVE FORMED ACROSS EASTERN AREAS AS WELL AS ALONG THE RIO GRANDE EARLY THIS MORNING. THE FOG AND CLOUDS WILL CONTINUE TO EXPAND INTO THE I-35 CORRIDOR AND PORTIONS OF THE HILL COUNTRY THROUGH THE MORNING HOURS. THE MUCH ADVERTISED ARCTIC AIRMASS HAS MOVED THROUGH THE HILL COUNTRY AND INTO WEST TEXAS. THE AIRMASS IN RELATIVELY DENSE BEHIND A 1055MB HIGH ANALYZED UP IN MONTANA. THE AIRMASS WILL GRADUALLY FILTER INTO SOUTH-CENTRAL TEXAS TODAY AND TONIGHT. ISENTROPIC ASCENT ABOVE THE SHALLOW...COLD AIRMASS WELL DEVELOP TONIGHT AND GRADUALLY STRENGTHEN WEDNESDAY AND WEDNESDAY NIGHT. INITIALLY THICK CLOUDS WILL RESULT FROM THIS...WITH ONLY PATCHY DRIZZLE AND PATCHY LIGHT RAIN DEVELOPING ACROSS THE WESTERN CWA TONIGHT AND EXPANDING EAST ON WEDNESDAY. THE GFS CONTINUES TO BE DRIER IN THE LOWEST LEVELS TODAY THROUGH WEDNESDAY...TAKING LONGER TO MOISTEN. HOWEVER FORECAST SOUNDINGS FROM THE HRRR/ARW/NMM AS WELL AS NAM12 ARE NOT QUITE AS AGGRESSIVE WITH THIS DRY LAYER AND MOISTENS FASTER. HAVE FOLLOWED SLIGHTLY CLOSER TO THE LATTER. THIS COULD POTENTIALLY RESULT IN PATCHY FREEZING DRIZZLE AND FREEZING LIGHT RAIN ALONG AND NORTH OF A PANDALE TO LEAKY TO JOHNSON CITY TO BURNET LINE EARLY WEDNESDAY MORNING. QPF AMOUNTS SHOULD BE VERY LIGHT...AND GIVEN GROUND TEMPS AND PATCHY COVERAGE IMPACTS SHOULD BE LIMITED TO ELEVATED SURFACES WITH MINIMAL TRAVEL IMPACTS. ON WEDNESDAY VERY LITTLE DIURNAL TEMPERATURE RANGE IS EXPECTED... WITH HIGHS ONLY CLIMBING INTO THE MID 30S ACROSS THE HILL COUNTRY (WITH A FEW ISOLATED HILL COUNTRY SPOTS REMAINING IN THE LOW 30S)...UPPER 30S ALONG THE I-35 CORRIDOR AND LOW 40S ALONG THE RIO GRANDE AS WELL AS FAR SOUTHERN/SOUTHEAST AREAS. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... FREEZING RAIN WITH TRAVEL IMPACTS POSSIBLE LATE NEW YEARS EVE INTO NEW YEARS DAY ACROSS THE HILL COUNTRY. WINTER STORM WATCH POSTED... THE UPPER LEVEL LOW ACROSS SOUTHERN CALIFORNIA IS FORECAST TO MOVE EAST INTO ARIZONA NEW YEARS EVE NIGHT INTO NEW YEARS DAY. THE ISENTROPIC UPGLIDE OVER THE COLD AIRMASS STRENGTHENS WEST TO EAST DURING THIS TIME. SEVERAL MODELS HAVE BEEN INDICATING FOR A FEW RUNS NOW A MID AND UPPER LEVEL SHORTWAVE IN THE SOUTHWEST FLOW ALOFT MOVING OUT OF MEXICO AND INTO WEST-CENTRAL TEXAS AND THE HILL COUNTRY LATE WEDNESDAY NIGHT AND THURSDAY. GFS AND ECMWF BOTH SHOW ENHANCED BAND OF QPF CLIPPING THE HILL COUNTRY...ALONG WITH SREF OUTPUT. CONFIDENCE CONTINUES TO GROW IN FREEZING RAIN EVENT LATE WEDNESDAY NIGHT THROUGH MIDDAY THURSDAY ACROSS AT LEAST THE HILL COUNTRY. THE WARM CLOUD LAYER DEPTH IS INCREASING DURING THIS TIME...BUT CAN NOT COMPLETELY RULE OUT SLEET MIXING IN ACROSS THE NORTHERN HILL COUNTRY AS WELL. GIVEN HOLIDAY TRAVEL SENSITIVITY... AND AFTER COORDINATION WITH SURROUNDING WFOS...WE HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR THE HILL COUNTRY...ALONG AND NORTH OF A VAL VERDE TO BANDERA TO BURNET COUNTY LINE. IF TEMPS AND ENHANCEMENT IN QPF VERIFY...THERE COULD BE A BAND ACROSS THE NORTHERN HILL COUNTRY OF HIGHER ICE ACCUMULATION AMOUNTS. FARTHER EAST ALONG THE I-35 CORRIDOR...TEMPERATURES WILL BE VERY CLOSE TO FREEZING EARLY THURSDAY MORNING. ALTHOUGH THESE COUNTIES ARE NOT CURRENTLY IN THE WATCH...THE FREEZING RAIN LINE IS FORECAST TO REACH A HELOTES TO WIMBERLEY TO GEORGETOWN LINE. ANY TRENDS DOWNWARD IN THE TEMP FORECAST...OR WET-BULB COOLING...COULD PUSH THIS LINE TOWARDS THE AUSTIN AND NORTHERN SAN ANTONIO METRO AREAS. THOSE WITH TRAVEL PLANS NEW YEARS EVE NIGHT INTO NEW YEARS DAY ALONG THE INTERSTATE 35 CORRIDOR SHOULD CLOSELY MONITOR FOR ANY FORECASTS UPDATES. MODELS ARE SLIGHTLY SLOWER WITH HOW FAST THE UPPER LEVEL LOW EJECTS OUT INTO THE PLAINS FROM RUNS A FEW DAYS AGO. THE UPPER LEVEL LOW MOVES ACROSS SOUTHERN NEW MEXICO FRIDAY AND NORTHEAST THROUGH WEST TEXAS FRIDAY NIGHT INTO SATURDAY MORNING. GOOD CHANCES FOR RAIN WILL CONTINUE ACROSS THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE WARM CLOUD LAYER CONTINUES TO WARM FURTHER WITH SLIGHT MODIFICATION IN THE COLD AIRMASS BELOW. PRECIP WILL REMAIN ALL LIQUID DURING THIS TIME (ALTHOUGH MAY HAVE TO WATCH CLOSELY ACROSS FAR NORTHERN AREAS OF THE CWA THURSDAY NIGHT). IN ADDITION...THERE WILL ALSO BE THE POTENTIAL FOR EMBEDDED THUNDER THURSDAY NIGHT THROUGH FRIDAY NIGHT AS ELEVATED LAPSE RATES STEEPEN...AND HAVE CONTINUED THIS IN THE FORECAST. CLEARING AND DRYING TAKES PLACE DOES EVENTUALLY TAKE PLACE WEST TO EAST SATURDAY WITH HIGHS TEMPS WARMING BACK TO TOWARDS SEASONABLE LEVELS OVER THE WEEKEND AND INTO EARLY NEXT WEEK. JR && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 52 34 38 34 40 / 10 10 20 30 60 AUSTIN BERGSTROM INTL AIRPORT 52 35 38 34 40 / 10 10 20 30 60 NEW BRAUNFELS MUNI AIRPORT 54 36 38 34 39 / 10 10 20 30 50 BURNET MUNI AIRPORT 48 30 36 29 37 / 10 10 20 30 60 DEL RIO INTL AIRPORT 54 36 41 33 44 / 10 40 30 30 20 GEORGETOWN MUNI AIRPORT 49 32 36 31 38 / 10 10 20 30 60 HONDO MUNI AIRPORT 56 36 39 33 42 / 10 20 20 30 40 SAN MARCOS MUNI AIRPORT 53 35 38 34 40 / 10 10 20 30 60 LA GRANGE - FAYETTE REGIONAL 55 36 41 36 42 / 10 10 20 30 50 SAN ANTONIO INTL AIRPORT 55 36 39 35 41 / 10 10 20 30 50 STINSON MUNI AIRPORT 56 38 39 36 41 / 10 10 20 30 50 && .EWX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING COUNTIES: BANDERA...BEXAR...BLANCO...BURNET...COMAL...EDWARDS...GILLESPIE... HAYS...KENDALL...KERR...KINNEY...LLANO...MAVERICK...MEDINA...REAL... TRAVIS...UVALDE...VAL VERDE...WILLIAMSON...ZAVALA. WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE. && $$ MESOSCALE/AVIATION...03 SYNOPTIC/GRIDS...12 PUBLIC SERVICE/DATA COLLECTION...00
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
921 AM CST TUE DEC 30 2014 .UPDATE... ISSUED A WINTER WEATHER ADVISORY FOR FREEZING DRIZZLE ON THE CAPROCK UNTIL NOON. MAY NEED TO EXTEND THIS AFTERNOON...AND IF SO WILL CONSIDER GOING THROUGH MUCH OF THE NIGHT. VERY COLD AIR MOVING SOUTHWARD SHOULD CHANGE FREEZING DRIZZLE MORE TO LIGHT SNOW AND PERHAPS LESS ICE ACCUMULATIONS BUT NOT CERTAIN AT THIS TIME. RMCQUEEN && .PREV DISCUSSION... /ISSUED 544 AM CST TUE DEC 30 2014/ UPDATE... KLBB 88D SHOWING THE EXPANSION OF VERY LIGHT REFLECTIVTY /ZERO TO MINUS 15 DBZ/ BTWN 1000 AND 5000 FT AGL AND LOWERING WITH TIME. THIS SHOULD BE THE PERIOD OF VERY LIGHT FLURRIES AND/OR FREEZING DRIZZLE ASSOCIATED WITH FRONTOGENTICAL FORCING. PER THE HRRR THIS PRECIP SHOULD SHIFT SWD WITH THE FORCING THROUGH THE MORNING. EXPECTATION IS IT SHOULD REMAIN TOO LIGHT CAUSE MUCH IN THE WAY OF DIFFICULTY THIS MORNING...BUT WILL CONTINUE TO MONITOR TRENDS. AVIATION... CIGS TO LOWER A BIT MORE DURING THE FIRST PART OF THE FCST PERIOD BUT SHOULD REMAIN MVFR THEN REMAIN PRETTY STABLE THROUGH THE REMAINDER OF THE PERIOD. ANTICIPATE SOME PERIODS OF LIGHT FREEZING DRIZZLE AND/OR FLURRIES THROUGH THE FCST TIME AS WELL. GUSTY NNE WINDS THROUGH MUCH OF THE DAY SHOULD RELAX TOWARD EVENING. PREV DISCUSSION... /ISSUED 428 AM CST TUE DEC 30 2014/ SHORT TERM... THE COLD FRONT IS NOW WELL INTO THE PERMIAN BASIN AND BIG COUNTRY WITH MUCH COLDER AIR FILTERING IN BEHIND IT RATHER THAN SURGING AT THIS POINT. WITH A GOOD STRATUS DECK NOW IN PLACE...ALTHOUGH NOT TERRIBLY LOW AT ABOUT 2000 FT AGL...AND LOW LEVEL COLD ADVECTION PERSISTING THROUGH THE DAY...TEMPS WILL HAVE TROUBLE MOVING OFF OF MORNING LOWS. INDEED...WILL LIKELY SEE TEMPS FALL THROUGH ABOUT MID-MORNING BEFORE SOME SLIGHT RECOVERY LATER IN THE DAY. HOWEVER...MAIN FOCUS CONTINUES TO BE ON CHANCE FOR VERY LIGHT PRECIPITATION TODAY AND TONIGHT AND POTENTIAL IMPACTS OF IT WITH TEMPS IN THE TEENS AND 20S. THIS PRECIP EVENT CONTINUES TO LOOK PRIMARILY ISENTROPIC DRIVEN WITH SOME MINOR CONTRIBUTION FROM FRONTOGENETICAL FORCING EARLY ON. ISENTROPIC PROJECTIONS DEPICT LIFT INITIALLY AT THE VERY TOP OF THE COLD AIR...PRIMARILY IN THE WARMER AND DRIER MID LEVELS ABOVE IT. HOWEVER...AS THE COLD AIR DEEPENS THROUGH THE DAY...SOME OF THIS COLD MOISTURE SHOULD BE TAPPED BY THE ISENTROPIC LIFT TO PRODUCE SOME LIGHT PRECIP. BEST WINDOW FOR THIS APPEARS TO BE BETWEEN 3 PM AND MIDNIGHT...AFTER WHICH ISENTROPIC LIFT WEAKENS SIGNIFICANTLY. QUESTION THEN BECOMES PHASE OF THIS PRECIPITATION. PROGGED SOUNDINGS SUPPORT EITHER FREEZING DRIZZLE OR VERY LIGHT SNOW. COLDER LOW LEVELS ACROSS THE NORTH AND WEST MIGHT END UP FAVORING FLURRIES TO A DUSTING OF SNOW WHILE FURTHER SOUTH AND EAST FREEZING DRIZZLE LIKELY TO BE PREDOMINANT. HOW MUCH IS A BIG QUESTION WITH SOUNDINGS SUGGESTING THE MODEL QPF OUTPUT IS OVERDONE. AS FOR POTENTIAL FOR ADVISORY...STILL SOME DETAILS TO WORK OUT SUCH AS FLURRIES VS DRIZZLE AND TIMING OF ONSET OF PRECIP HEAVY AND/OR WIDESPREAD ENOUGH TO BEGIN TO CAUSE TRAVEL ISSUES. SINCE CURRENT EXPECTATION IS THE MORE SIGNIFICANT PART OF THE EVENT IS STILL 8-12 HOURS AWAY AND ANOTHER MODEL RUN AND 12Z UA ANALYSIS SHOULD HELP NARROW DOWN THE DETAILS FURTHER...WILL DEFER ON THE ISSUANCE OF AN ADVISORY ATTM. LONG TERM... AN UA DISTURBANCE ACROSS THE GREAT BASIN IS STILL PROGGED TO PINCH OFF AND DIVE SSE TO ACROSS SRN CALI TOMORROW...AND ACROSS THE DESERT SW ON THURSDAY. AS SUCH...FLOW ALOFT WILL EVOLVE FROM A BROAD CYCLONIC FLOW TO SWRLY FLOW. IF THE ANTICIPATED TRACK OF THE SYSTEM DOES NOT CHANGE...IT WILL MOVE DIRECTLY ACROSS THE SOUTHERN PLAINS FRIDAY NIGHT THEN EXIT TO THE NE BY SATURDAY. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL. TEMPS STRUGGLING TO GET OUT OF THE 20S WILL CHARACTERIZE WEDNESDAY AS THE CAA USHERED IN BY LAST NIGHT/S COLD FRONTAL PASSAGE REMAINS ENTRENCHED. FURTHERMORE...MAY ALSO EXPERIENCE A LINGERING FREEZING DRIZZLE/WINTRY MIX...COURTESY OF MOISTENED ATMOSPHERIC LOW LEVELS AND AN UPSLOPE SFC REGIME. THIS WINTRY MIX MAY BE HARD-PRESSED TO REACH THE GROUND AS IT WILL HAVE TO FALL THROUGH RATHER DRY MID-LEVELS...WHICH IS WHERE THE SLIVER OF UL SUPPORT IS MAXIMIZED. ON THURSDAY DURING THE DAY...A SIMILAR SCENARIO TO WEDNESDAY WILL PLAY OUT...WITH THE DIFFERENCE BEING PROGGED MODEL SOUNDINGS HINTING AT A WARM TONGUE DEVELOPING IN THE MID-LEVELS...THUS SUGGESTING MORE OF A FREEZING RAIN/WINTRY MIX OCCURRENCE. NONETHELESS...THE BEST LIFT IS STILL MAXIMIZED WITHIN THE DRY MID-LEVELS AND HENCE LIGHT PRECIP IS EXPECTED. BY THURSDAY NIGHT HOWEVER...MID-LEVELS ARE SHOWN TO MOISTEN AS THE UA SYSTEM DRAWS NEAR. THE BEST UL SUPPORT IS FINALLY TAPPING INTO ADEQUATE MOISTURE. MID-LEVEL MOISTENING OCCURRING WITHIN THE DENDRITIC ZONE COULD PROMOTE A CHANCE OF SNOW...PARTICULARLY ACROSS THE HIGHER TERRAIN OF THE NWRN ZONES. ELSEWHERE...FREEZING RAIN AND PERHAPS SLEET WILL BE COMMON...WITH THE EXCEPTION OF THE FAR ROLLING PLAINS WHERE A MIX OF A COLD RAIN AND FREEZING RAIN MAY OCCUR...GIVEN TEMPS WILL WARM TO SLIGHTLY ABOVE FREEZING THERE /LOWER 30S ELSEWHERE/. TEMPS WILL WARMUP FURTHER ON FRIDAY...INTO THE MIDDLE TO UPPER 30S ON THE CAPROCK TO UPPER 30S TO LOWER 40S OFF THE CAPROCK...WHICH WILL AFFECT THE PRECIP PHASE. COULD THEREFORE SEE MORE OF A RAIN AND SNOW MIX OR A RAIN AND FREEZING RAIN MIX DEVELOP BY THE EVENING /THE NWRN ZONES WILL BE THE EXCEPTION AS SOUNDING PROFILES SUGGEST LIGHT SNOW THERE/. LATE FRIDAY NIGHT-EARLY SATURDAY MORNING...LARGE SCALE ASCENT WILL BE FLEETING AS THE SYSTEM COMMENCE TO EXIT THE REGION. PERHAPS SOME LINGERING RAIN AND SNOW MIX WILL BE POSSIBLE ACROSS PORTIONS OF THE ROLLING PLAINS EARLY SATURDAY MORNING. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL AND THE RETURN TO SRLY SFC FLOW EARLY NEXT WEEK WILL AID IN PUSHING TEMPS BACK UP TO NEAR 50. NOTE: ALTHOUGH THE WINTRY PRECIP IS EXPECTED TO BE LIGHT THIS WEEK...IT COULD STILL POSE A THREAT FOR HAZARDOUS ROAD CONDITIONS AS A THIN GLAZE OF ICE COULD FORM ACROSS OVERPASSES AND BRIDGES IN PARTICULAR. AS YOU HEAD OUT TO ENJOY THE NEW YEAR FESTIVITIES...CAUTION IS ADVISED. CHECK BACK TO STAY ALERT AND UP TO DATE WITH ANY WEATHER CHANGES. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 20 11 22 17 32 / 30 40 20 10 20 TULIA 22 13 22 19 32 / 30 40 10 10 20 PLAINVIEW 23 14 23 19 32 / 30 40 10 10 20 LEVELLAND 24 16 24 19 32 / 40 50 20 20 20 LUBBOCK 25 16 25 21 32 / 40 50 20 20 20 DENVER CITY 27 18 25 20 33 / 40 50 20 20 30 BROWNFIELD 27 18 25 20 33 / 40 50 20 20 30 CHILDRESS 28 18 25 22 34 / 30 40 10 10 20 SPUR 28 18 25 22 33 / 30 50 20 20 30 ASPERMONT 30 20 27 24 36 / 30 40 20 20 30 && .LUB WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING ZONES: TXZ021>024-027>030-033>036-039>042. && $$ 05/99
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
725 AM CST TUE DEC 30 2014 .UPDATE...ONE FINAL UPDATE TO EXPAND DENSE FOG ADVISORY WEST TO THE RIO GRANDE. && .PREV DISCUSSION... /ISSUED 613 AM CST TUE DEC 30 2014/ AVIATION... LIFR/VLIFR VIS AND CIGS IN AUSTIN AND SAN ANTONIO THIS MORNING WILL CONTINUE UNTIL MID-MORNING WHEN NORTHWESTERLY WINDS PICK UP. THEN MVFR/IFR CIGS THROUGH THE REST OF THE TAF PERIOD. DRT WILL DROP TO IFR SHORTLY AND STAY THAT WAY UNTIL AROUND 18Z. EXPECTING PRECIPITATION WEDNESDAY MORNING AT DRT. HAVE NOT INCLUDED ANY PRECIP IN AUSTIN OR SAN ANTONIO...BUT THERE IS A SLIGHT CHANCE FOR RAIN. IF THERE IS ANY RAIN IT WILL DROP VIS TO MVFR. PREV DISCUSSION... /ISSUED 523 AM CST TUE DEC 30 2014/ UPDATE...SECOND UPDATE TO EXPAND DENSE FOG ADVISORY FARTHER WEST AND SOUTH BASED ON SATELLITE AND WEB CAM TRENDS. THIS ALSO LINES UP WELL WITH HRRR EXPANSION OF FOG. PREV DISCUSSION... /ISSUED 443 AM CST TUE DEC 30 2014/ UPDATE...QUICK UPDATE TO ISSUE DENSE FOG ADVISORY FOR I-35 CORRIDOR FROM COMAL TO WILLIAMSON COUNTY EASTWARD. THIS IS BASED ON SEVERAL WEBCAMS AND OBS INDICATING DENSE FOG. THERE IS ALSO THE POTENTIAL FOR PATCHY TO AREAS OF DENSE FOG SOUTH AND WEST OF THE ADVISORY AREA THROUGH THE MORNING. PREV DISCUSSION... /ISSUED 401 AM CST TUE DEC 30 2014/ SHORT TERM (TODAY THROUGH WEDNESDAY)...AREAS OF LOW STRATUS AND FOG HAVE FORMED ACROSS EASTERN AREAS AS WELL AS ALONG THE RIO GRANDE EARLY THIS MORNING. THE FOG AND CLOUDS WILL CONTINUE TO EXPAND INTO THE I-35 CORRIDOR AND PORTIONS OF THE HILL COUNTRY THROUGH THE MORNING HOURS. THE MUCH ADVERTISED ARCTIC AIRMASS HAS MOVED THROUGH THE HILL COUNTRY AND INTO WEST TEXAS. THE AIRMASS IN RELATIVELY DENSE BEHIND A 1055MB HIGH ANALYZED UP IN MONTANA. THE AIRMASS WILL GRADUALLY FILTER INTO SOUTH-CENTRAL TEXAS TODAY AND TONIGHT. ISENTROPIC ASCENT ABOVE THE SHALLOW...COLD AIRMASS WELL DEVELOP TONIGHT AND GRADUALLY STRENGTHEN WEDNESDAY AND WEDNESDAY NIGHT. INITIALLY THICK CLOUDS WILL RESULT FROM THIS...WITH ONLY PATCHY DRIZZLE AND PATCHY LIGHT RAIN DEVELOPING ACROSS THE WESTERN CWA TONIGHT AND EXPANDING EAST ON WEDNESDAY. THE GFS CONTINUES TO BE DRIER IN THE LOWEST LEVELS TODAY THROUGH WEDNESDAY...TAKING LONGER TO MOISTEN. HOWEVER FORECAST SOUNDINGS FROM THE HRRR/ARW/NMM AS WELL AS NAM12 ARE NOT QUITE AS AGGRESSIVE WITH THIS DRY LAYER AND MOISTENS FASTER. HAVE FOLLOWED SLIGHTLY CLOSER TO THE LATTER. THIS COULD POTENTIALLY RESULT IN PATCHY FREEZING DRIZZLE AND FREEZING LIGHT RAIN ALONG AND NORTH OF A PANDALE TO LEAKY TO JOHNSON CITY TO BURNET LINE EARLY WEDNESDAY MORNING. QPF AMOUNTS SHOULD BE VERY LIGHT...AND GIVEN GROUND TEMPS AND PATCHY COVERAGE IMPACTS SHOULD BE LIMITED TO ELEVATED SURFACES WITH MINIMAL TRAVEL IMPACTS. ON WEDNESDAY VERY LITTLE DIURNAL TEMPERATURE RANGE IS EXPECTED... WITH HIGHS ONLY CLIMBING INTO THE MID 30S ACROSS THE HILL COUNTRY (WITH A FEW ISOLATED HILL COUNTRY SPOTS REMAINING IN THE LOW 30S)...UPPER 30S ALONG THE I-35 CORRIDOR AND LOW 40S ALONG THE RIO GRANDE AS WELL AS FAR SOUTHERN/SOUTHEAST AREAS. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... FREEZING RAIN WITH TRAVEL IMPACTS POSSIBLE LATE NEW YEARS EVE INTO NEW YEARS DAY ACROSS THE HILL COUNTRY. WINTER STORM WATCH POSTED... THE UPPER LEVEL LOW ACROSS SOUTHERN CALIFORNIA IS FORECAST TO MOVE EAST INTO ARIZONA NEW YEARS EVE NIGHT INTO NEW YEARS DAY. THE ISENTROPIC UPGLIDE OVER THE COLD AIRMASS STRENGTHENS WEST TO EAST DURING THIS TIME. SEVERAL MODELS HAVE BEEN INDICATING FOR A FEW RUNS NOW A MID AND UPPER LEVEL SHORTWAVE IN THE SOUTHWEST FLOW ALOFT MOVING OUT OF MEXICO AND INTO WEST-CENTRAL TEXAS AND THE HILL COUNTRY LATE WEDNESDAY NIGHT AND THURSDAY. GFS AND ECMWF BOTH SHOW ENHANCED BAND OF QPF CLIPPING THE HILL COUNTRY...ALONG WITH SREF OUTPUT. CONFIDENCE CONTINUES TO GROW IN FREEZING RAIN EVENT LATE WEDNESDAY NIGHT THROUGH MIDDAY THURSDAY ACROSS AT LEAST THE HILL COUNTRY. THE WARM CLOUD LAYER DEPTH IS INCREASING DURING THIS TIME...BUT CAN NOT COMPLETELY RULE OUT SLEET MIXING IN ACROSS THE NORTHERN HILL COUNTRY AS WELL. GIVEN HOLIDAY TRAVEL SENSITIVITY... AND AFTER COORDINATION WITH SURROUNDING WFOS...WE HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR THE HILL COUNTRY...ALONG AND NORTH OF A VAL VERDE TO BANDERA TO BURNET COUNTY LINE. IF TEMPS AND ENHANCEMENT IN QPF VERIFY...THERE COULD BE A BAND ACROSS THE NORTHERN HILL COUNTRY OF HIGHER ICE ACCUMULATION AMOUNTS. FARTHER EAST ALONG THE I-35 CORRIDOR...TEMPERATURES WILL BE VERY CLOSE TO FREEZING EARLY THURSDAY MORNING. ALTHOUGH THESE COUNTIES ARE NOT CURRENTLY IN THE WATCH...THE FREEZING RAIN LINE IS FORECAST TO REACH A HELOTES TO WIMBERLEY TO GEORGETOWN LINE. ANY TRENDS DOWNWARD IN THE TEMP FORECAST...OR WET-BULB COOLING...COULD PUSH THIS LINE TOWARDS THE AUSTIN AND NORTHERN SAN ANTONIO METRO AREAS. THOSE WITH TRAVEL PLANS NEW YEARS EVE NIGHT INTO NEW YEARS DAY ALONG THE INTERSTATE 35 CORRIDOR SHOULD CLOSELY MONITOR FOR ANY FORECASTS UPDATES. MODELS ARE SLIGHTLY SLOWER WITH HOW FAST THE UPPER LEVEL LOW EJECTS OUT INTO THE PLAINS FROM RUNS A FEW DAYS AGO. THE UPPER LEVEL LOW MOVES ACROSS SOUTHERN NEW MEXICO FRIDAY AND NORTHEAST THROUGH WEST TEXAS FRIDAY NIGHT INTO SATURDAY MORNING. GOOD CHANCES FOR RAIN WILL CONTINUE ACROSS THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE WARM CLOUD LAYER CONTINUES TO WARM FURTHER WITH SLIGHT MODIFICATION IN THE COLD AIRMASS BELOW. PRECIP WILL REMAIN ALL LIQUID DURING THIS TIME (ALTHOUGH MAY HAVE TO WATCH CLOSELY ACROSS FAR NORTHERN AREAS OF THE CWA THURSDAY NIGHT). IN ADDITION...THERE WILL ALSO BE THE POTENTIAL FOR EMBEDDED THUNDER THURSDAY NIGHT THROUGH FRIDAY NIGHT AS ELEVATED LAPSE RATES STEEPEN...AND HAVE CONTINUED THIS IN THE FORECAST. CLEARING AND DRYING TAKES PLACE DOES EVENTUALLY TAKE PLACE WEST TO EAST SATURDAY WITH HIGHS TEMPS WARMING BACK TO TOWARDS SEASONABLE LEVELS OVER THE WEEKEND AND INTO EARLY NEXT WEEK. JR && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 52 34 38 34 40 / 10 10 20 30 60 AUSTIN BERGSTROM INTL AIRPORT 52 35 38 34 40 / 10 10 20 30 60 NEW BRAUNFELS MUNI AIRPORT 54 36 38 34 39 / 10 10 20 30 50 BURNET MUNI AIRPORT 48 30 36 29 37 / 10 10 20 30 60 DEL RIO INTL AIRPORT 54 36 41 33 44 / 10 40 30 30 20 GEORGETOWN MUNI AIRPORT 49 32 36 31 38 / 10 10 20 30 60 HONDO MUNI AIRPORT 56 36 39 33 42 / 10 20 20 30 40 SAN MARCOS MUNI AIRPORT 53 35 38 34 40 / 10 10 20 30 60 LA GRANGE - FAYETTE REGIONAL 55 36 41 36 42 / 10 10 20 30 50 SAN ANTONIO INTL AIRPORT 55 36 39 35 41 / 10 10 20 30 50 STINSON MUNI AIRPORT 56 38 39 36 41 / 10 10 20 30 50 && .EWX WATCHES/WARNINGS/ADVISORIES... DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR THE FOLLOWING COUNTIES: ATASCOSA...BANDERA...BASTROP...BEXAR...BLANCO...BURNET... CALDWELL...COMAL...DIMMIT...EDWARDS...FAYETTE...FRIO...GILLESPIE... GONZALES...GUADALUPE...HAYS...KENDALL...KERR...KINNEY...LEE... LLANO...MAVERICK...MEDINA...REAL...TRAVIS...UVALDE...VAL VERDE... WILLIAMSON...WILSON...ZAVALA. WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE. && $$ MESOSCALE/AVIATION...05 SYNOPTIC/GRIDS...76
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
613 AM CST TUE DEC 30 2014 .AVIATION... LIFR/VLIFR VIS AND CIGS IN AUSTIN AND SAN ANTONIO THIS MORNING WILL CONTINUE UNTIL MID-MORNING WHEN NORTHWESTERLY WINDS PICK UP. THEN MVFR/IFR CIGS THROUGH THE REST OF THE TAF PERIOD. DRT WILL DROP TO IFR SHORTLY AND STAY THAT WAY UNTIL AROUND 18Z. EXPECTING PRECIPITATION WEDNESDAY MORNING AT DRT. HAVE NOT INCLUDED ANY PRECIP IN AUSTIN OR SAN ANTONIO...BUT THERE IS A SLIGHT CHANCE FOR RAIN. IF THERE IS ANY RAIN IT WILL DROP VIS TO MVFR. && .PREV DISCUSSION... /ISSUED 523 AM CST TUE DEC 30 2014/ UPDATE...SECOND UPDATE TO EXPAND DENSE FOG ADVISORY FARTHER WEST AND SOUTH BASED ON SATELLITE AND WEB CAM TRENDS. THIS ALSO LINES UP WELL WITH HRRR EXPANSION OF FOG. PREV DISCUSSION... /ISSUED 443 AM CST TUE DEC 30 2014/ UPDATE...QUICK UPDATE TO ISSUE DENSE FOG ADVISORY FOR I-35 CORRIDOR FROM COMAL TO WILLIAMSON COUNTY EASTWARD. THIS IS BASED ON SEVERAL WEBCAMS AND OBS INDICATING DENSE FOG. THERE IS ALSO THE POTENTIAL FOR PATCHY TO AREAS OF DENSE FOG SOUTH AND WEST OF THE ADVISORY AREA THROUGH THE MORNING. PREV DISCUSSION... /ISSUED 401 AM CST TUE DEC 30 2014/ SHORT TERM (TODAY THROUGH WEDNESDAY)...AREAS OF LOW STRATUS AND FOG HAVE FORMED ACROSS EASTERN AREAS AS WELL AS ALONG THE RIO GRANDE EARLY THIS MORNING. THE FOG AND CLOUDS WILL CONTINUE TO EXPAND INTO THE I-35 CORRIDOR AND PORTIONS OF THE HILL COUNTRY THROUGH THE MORNING HOURS. THE MUCH ADVERTISED ARCTIC AIRMASS HAS MOVED THROUGH THE HILL COUNTRY AND INTO WEST TEXAS. THE AIRMASS IN RELATIVELY DENSE BEHIND A 1055MB HIGH ANALYZED UP IN MONTANA. THE AIRMASS WILL GRADUALLY FILTER INTO SOUTH-CENTRAL TEXAS TODAY AND TONIGHT. ISENTROPIC ASCENT ABOVE THE SHALLOW...COLD AIRMASS WELL DEVELOP TONIGHT AND GRADUALLY STRENGTHEN WEDNESDAY AND WEDNESDAY NIGHT. INITIALLY THICK CLOUDS WILL RESULT FROM THIS...WITH ONLY PATCHY DRIZZLE AND PATCHY LIGHT RAIN DEVELOPING ACROSS THE WESTERN CWA TONIGHT AND EXPANDING EAST ON WEDNESDAY. THE GFS CONTINUES TO BE DRIER IN THE LOWEST LEVELS TODAY THROUGH WEDNESDAY...TAKING LONGER TO MOISTEN. HOWEVER FORECAST SOUNDINGS FROM THE HRRR/ARW/NMM AS WELL AS NAM12 ARE NOT QUITE AS AGGRESSIVE WITH THIS DRY LAYER AND MOISTENS FASTER. HAVE FOLLOWED SLIGHTLY CLOSER TO THE LATTER. THIS COULD POTENTIALLY RESULT IN PATCHY FREEZING DRIZZLE AND FREEZING LIGHT RAIN ALONG AND NORTH OF A PANDALE TO LEAKY TO JOHNSON CITY TO BURNET LINE EARLY WEDNESDAY MORNING. QPF AMOUNTS SHOULD BE VERY LIGHT...AND GIVEN GROUND TEMPS AND PATCHY COVERAGE IMPACTS SHOULD BE LIMITED TO ELEVATED SURFACES WITH MINIMAL TRAVEL IMPACTS. ON WEDNESDAY VERY LITTLE DIURNAL TEMPERATURE RANGE IS EXPECTED... WITH HIGHS ONLY CLIMBING INTO THE MID 30S ACROSS THE HILL COUNTRY (WITH A FEW ISOLATED HILL COUNTRY SPOTS REMAINING IN THE LOW 30S)...UPPER 30S ALONG THE I-35 CORRIDOR AND LOW 40S ALONG THE RIO GRANDE AS WELL AS FAR SOUTHERN/SOUTHEAST AREAS. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... FREEZING RAIN WITH TRAVEL IMPACTS POSSIBLE LATE NEW YEARS EVE INTO NEW YEARS DAY ACROSS THE HILL COUNTRY. WINTER STORM WATCH POSTED... THE UPPER LEVEL LOW ACROSS SOUTHERN CALIFORNIA IS FORECAST TO MOVE EAST INTO ARIZONA NEW YEARS EVE NIGHT INTO NEW YEARS DAY. THE ISENTROPIC UPGLIDE OVER THE COLD AIRMASS STRENGTHENS WEST TO EAST DURING THIS TIME. SEVERAL MODELS HAVE BEEN INDICATING FOR A FEW RUNS NOW A MID AND UPPER LEVEL SHORTWAVE IN THE SOUTHWEST FLOW ALOFT MOVING OUT OF MEXICO AND INTO WEST-CENTRAL TEXAS AND THE HILL COUNTRY LATE WEDNESDAY NIGHT AND THURSDAY. GFS AND ECMWF BOTH SHOW ENHANCED BAND OF QPF CLIPPING THE HILL COUNTRY...ALONG WITH SREF OUTPUT. CONFIDENCE CONTINUES TO GROW IN FREEZING RAIN EVENT LATE WEDNESDAY NIGHT THROUGH MIDDAY THURSDAY ACROSS AT LEAST THE HILL COUNTRY. THE WARM CLOUD LAYER DEPTH IS INCREASING DURING THIS TIME...BUT CAN NOT COMPLETELY RULE OUT SLEET MIXING IN ACROSS THE NORTHERN HILL COUNTRY AS WELL. GIVEN HOLIDAY TRAVEL SENSITIVITY... AND AFTER COORDINATION WITH SURROUNDING WFOS...WE HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR THE HILL COUNTRY...ALONG AND NORTH OF A VAL VERDE TO BANDERA TO BURNET COUNTY LINE. IF TEMPS AND ENHANCEMENT IN QPF VERIFY...THERE COULD BE A BAND ACROSS THE NORTHERN HILL COUNTRY OF HIGHER ICE ACCUMULATION AMOUNTS. FARTHER EAST ALONG THE I-35 CORRIDOR...TEMPERATURES WILL BE VERY CLOSE TO FREEZING EARLY THURSDAY MORNING. ALTHOUGH THESE COUNTIES ARE NOT CURRENTLY IN THE WATCH...THE FREEZING RAIN LINE IS FORECAST TO REACH A HELOTES TO WIMBERLEY TO GEORGETOWN LINE. ANY TRENDS DOWNWARD IN THE TEMP FORECAST...OR WET-BULB COOLING...COULD PUSH THIS LINE TOWARDS THE AUSTIN AND NORTHERN SAN ANTONIO METRO AREAS. THOSE WITH TRAVEL PLANS NEW YEARS EVE NIGHT INTO NEW YEARS DAY ALONG THE INTERSTATE 35 CORRIDOR SHOULD CLOSELY MONITOR FOR ANY FORECASTS UPDATES. MODELS ARE SLIGHTLY SLOWER WITH HOW FAST THE UPPER LEVEL LOW EJECTS OUT INTO THE PLAINS FROM RUNS A FEW DAYS AGO. THE UPPER LEVEL LOW MOVES ACROSS SOUTHERN NEW MEXICO FRIDAY AND NORTHEAST THROUGH WEST TEXAS FRIDAY NIGHT INTO SATURDAY MORNING. GOOD CHANCES FOR RAIN WILL CONTINUE ACROSS THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE WARM CLOUD LAYER CONTINUES TO WARM FURTHER WITH SLIGHT MODIFICATION IN THE COLD AIRMASS BELOW. PRECIP WILL REMAIN ALL LIQUID DURING THIS TIME (ALTHOUGH MAY HAVE TO WATCH CLOSELY ACROSS FAR NORTHERN AREAS OF THE CWA THURSDAY NIGHT). IN ADDITION...THERE WILL ALSO BE THE POTENTIAL FOR EMBEDDED THUNDER THURSDAY NIGHT THROUGH FRIDAY NIGHT AS ELEVATED LAPSE RATES STEEPEN...AND HAVE CONTINUED THIS IN THE FORECAST. CLEARING AND DRYING TAKES PLACE DOES EVENTUALLY TAKE PLACE WEST TO EAST SATURDAY WITH HIGHS TEMPS WARMING BACK TO TOWARDS SEASONABLE LEVELS OVER THE WEEKEND AND INTO EARLY NEXT WEEK. JR && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 52 34 38 34 40 / 10 10 20 30 60 AUSTIN BERGSTROM INTL AIRPORT 52 35 38 34 40 / 10 10 20 30 60 NEW BRAUNFELS MUNI AIRPORT 54 36 38 34 39 / 10 10 20 30 50 BURNET MUNI AIRPORT 48 30 36 29 37 / 10 10 20 30 60 DEL RIO INTL AIRPORT 54 36 41 33 44 / 10 40 30 30 20 GEORGETOWN MUNI AIRPORT 49 32 36 31 38 / 10 10 20 30 60 HONDO MUNI AIRPORT 56 36 39 33 42 / 10 20 20 30 40 SAN MARCOS MUNI AIRPORT 53 35 38 34 40 / 10 10 20 30 60 LA GRANGE - FAYETTE REGIONAL 55 36 41 36 42 / 10 10 20 30 50 SAN ANTONIO INTL AIRPORT 55 36 39 35 41 / 10 10 20 30 50 STINSON MUNI AIRPORT 56 38 39 36 41 / 10 10 20 30 50 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE. DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING COUNTIES: ATASCOSA...BANDERA...BASTROP...BEXAR...BLANCO...BURNET... CALDWELL...COMAL...DIMMIT...FAYETTE...FRIO...GILLESPIE...GONZALES... GUADALUPE...HAYS...KENDALL...KERR...LEE...LLANO...MEDINA...TRAVIS... UVALDE...WILLIAMSON...WILSON...ZAVALA. && $$ MESOSCALE/AVIATION...05 SYNOPTIC/GRIDS...76
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
544 AM CST TUE DEC 30 2014 .UPDATE... KLBB 88D SHOWING THE EXPANSION OF VERY LIGHT REFLECTIVTY /ZERO TO MINUS 15 DBZ/ BTWN 1000 AND 5000 FT AGL AND LOWERING WITH TIME. THIS SHOULD BE THE PERIOD OF VERY LIGHT FLURRIES AND/OR FREEZING DRIZZLE ASSOCIATED WITH FRONTOGENTICAL FORCING. PER THE HRRR THIS PRECIP SHOULD SHIFT SWD WITH THE FORCING THROUGH THE MORNING. EXPECTATION IS IT SHOULD REMAIN TOO LIGHT CAUSE MUCH IN THE WAY OF DIFFICULTY THIS MORNING...BUT WILL CONTINUE TO MONITOR TRENDS. && .AVIATION... CIGS TO LOWER A BIT MORE DURING THE FIRST PART OF THE FCST PERIOD BUT SHOULD REMAIN MVFR THEN REMAIN PRETTY STABLE THROUGH THE REMAINDER OF THE PERIOD. ANTICIPATE SOME PERIODS OF LIGHT FREEZING DRIZZLE AND/OR FLURRIES THROUGH THE FCST TIME AS WELL. GUSTY NNE WINDS THROUGH MUCH OF THE DAY SHOULD RELAX TOWARD EVENING. && .PREV DISCUSSION... /ISSUED 428 AM CST TUE DEC 30 2014/ SHORT TERM... THE COLD FRONT IS NOW WELL INTO THE PERMIAN BASIN AND BIG COUNTRY WITH MUCH COLDER AIR FILTERING IN BEHIND IT RATHER THAN SURGING AT THIS POINT. WITH A GOOD STRATUS DECK NOW IN PLACE...ALTHOUGH NOT TERRIBLY LOW AT ABOUT 2000 FT AGL...AND LOW LEVEL COLD ADVECTION PERSISTING THROUGH THE DAY...TEMPS WILL HAVE TROUBLE MOVING OFF OF MORNING LOWS. INDEED...WILL LIKELY SEE TEMPS FALL THROUGH ABOUT MID-MORNING BEFORE SOME SLIGHT RECOVERY LATER IN THE DAY. HOWEVER...MAIN FOCUS CONTINUES TO BE ON CHANCE FOR VERY LIGHT PRECIPITATION TODAY AND TONIGHT AND POTENTIAL IMPACTS OF IT WITH TEMPS IN THE TEENS AND 20S. THIS PRECIP EVENT CONTINUES TO LOOK PRIMARILY ISENTROPIC DRIVEN WITH SOME MINOR CONTRIBUTION FROM FRONTOGENETICAL FORCING EARLY ON. ISENTROPIC PROJECTIONS DEPICT LIFT INITIALLY AT THE VERY TOP OF THE COLD AIR...PRIMARILY IN THE WARMER AND DRIER MID LEVELS ABOVE IT. HOWEVER...AS THE COLD AIR DEEPENS THROUGH THE DAY...SOME OF THIS COLD MOISTURE SHOULD BE TAPPED BY THE ISENTROPIC LIFT TO PRODUCE SOME LIGHT PRECIP. BEST WINDOW FOR THIS APPEARS TO BE BETWEEN 3 PM AND MIDNIGHT...AFTER WHICH ISENTROPIC LIFT WEAKENS SIGNIFICANTLY. QUESTION THEN BECOMES PHASE OF THIS PRECIPITATION. PROGGED SOUNDINGS SUPPORT EITHER FREEZING DRIZZLE OR VERY LIGHT SNOW. COLDER LOW LEVELS ACROSS THE NORTH AND WEST MIGHT END UP FAVORING FLURRIES TO A DUSTING OF SNOW WHILE FURTHER SOUTH AND EAST FREEZING DRIZZLE LIKELY TO BE PREDOMINANT. HOW MUCH IS A BIG QUESTION WITH SOUNDINGS SUGGESTING THE MODEL QPF OUTPUT IS OVERDONE. AS FOR POTENTIAL FOR ADVISORY...STILL SOME DETAILS TO WORK OUT SUCH AS FLURRIES VS DRIZZLE AND TIMING OF ONSET OF PRECIP HEAVY AND/OR WIDESPREAD ENOUGH TO BEGIN TO CAUSE TRAVEL ISSUES. SINCE CURRENT EXPECTATION IS THE MORE SIGNIFICANT PART OF THE EVENT IS STILL 8-12 HOURS AWAY AND ANOTHER MODEL RUN AND 12Z UA ANALYSIS SHOULD HELP NARROW DOWN THE DETAILS FURTHER...WILL DEFER ON THE ISSUANCE OF AN ADVISORY ATTM. LONG TERM... AN UA DISTURBANCE ACROSS THE GREAT BASIN IS STILL PROGGED TO PINCH OFF AND DIVE SSE TO ACROSS SRN CALI TOMORROW...AND ACROSS THE DESERT SW ON THURSDAY. AS SUCH...FLOW ALOFT WILL EVOLVE FROM A BROAD CYCLONIC FLOW TO SWRLY FLOW. IF THE ANTICIPATED TRACK OF THE SYSTEM DOES NOT CHANGE...IT WILL MOVE DIRECTLY ACROSS THE SOUTHERN PLAINS FRIDAY NIGHT THEN EXIT TO THE NE BY SATURDAY. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL. TEMPS STRUGGLING TO GET OUT OF THE 20S WILL CHARACTERIZE WEDNESDAY AS THE CAA USHERED IN BY LAST NIGHT/S COLD FRONTAL PASSAGE REMAINS ENTRENCHED. FURTHERMORE...MAY ALSO EXPERIENCE A LINGERING FREEZING DRIZZLE/WINTRY MIX...COURTESY OF MOISTENED ATMOSPHERIC LOW LEVELS AND AN UPSLOPE SFC REGIME. THIS WINTRY MIX MAY BE HARD-PRESSED TO REACH THE GROUND AS IT WILL HAVE TO FALL THROUGH RATHER DRY MID-LEVELS...WHICH IS WHERE THE SLIVER OF UL SUPPORT IS MAXIMIZED. ON THURSDAY DURING THE DAY...A SIMILAR SCENARIO TO WEDNESDAY WILL PLAY OUT...WITH THE DIFFERENCE BEING PROGGED MODEL SOUNDINGS HINTING AT A WARM TONGUE DEVELOPING IN THE MID-LEVELS...THUS SUGGESTING MORE OF A FREEZING RAIN/WINTRY MIX OCCURRENCE. NONETHELESS...THE BEST LIFT IS STILL MAXIMIZED WITHIN THE DRY MID-LEVELS AND HENCE LIGHT PRECIP IS EXPECTED. BY THURSDAY NIGHT HOWEVER...MID-LEVELS ARE SHOWN TO MOISTEN AS THE UA SYSTEM DRAWS NEAR. THE BEST UL SUPPORT IS FINALLY TAPPING INTO ADEQUATE MOISTURE. MID-LEVEL MOISTENING OCCURRING WITHIN THE DENDRITIC ZONE COULD PROMOTE A CHANCE OF SNOW...PARTICULARY ACROSS THE HIGHER TERRAIN OF THE NWRN ZONES. ELSEWHERE...FREEZING RAIN AND PERHAPS SLEET WILL BE COMMON...WITH THE EXCEPTION OF THE FAR ROLLING PLAINS WHERE A MIX OF A COLD RAIN AND FREEZING RAIN MAY OCCUR...GIVEN TEMPS WILL WARM TO SLIGHTLY ABOVE FREEZING THERE /LOWER 30S ELSEWHERE/. TEMPS WILL WARMUP FURTHER ON FRIDAY...INTO THE MIDDLE TO UPPER 30S ON THE CAPROCK TO UPPER 30S TO LOWER 40S OFF THE CAPROCK...WHICH WILL AFFECT THE PRECIP PHASE. COULD THEREFORE SEE MORE OF A RAIN AND SNOW MIX OR A RAIN AND FREEZING RAIN MIX DEVELOP BY THE EVENING /THE NWRN ZONES WILL BE THE EXCEPTION AS SOUNDING PROFILES SUGGEST LIGHT SNOW THERE/. LATE FRIDAY NIGHT-EARLY SATURDAY MORNING...LARGE SCALE ASCENT WILL BE FLEETING AS THE SYSTEM COMMENCE TO EXIT THE REGION. PERHAPS SOME LINGERING RAIN AND SNOW MIX WILL BE POSSIBLE ACROSS PORTIONS OF THE ROLLING PLAINS EARLY SATURDAY MORNING. THEREAFTER...DRY NW FLOW ALOFT WILL PREVAIL AND THE RETURN TO SRLY SFC FLOW EARLY NEXT WEEK WILL AID IN PUSHING TEMPS BACK UP TO NEAR 50. NOTE: ALTHOUGH THE WINTRY PRECIP IS EXPECTED TO BE LIGHT THIS WEEK...IT COULD STILL POSE A THREAT FOR HAZARDOUS ROAD CONDITIONS AS A THIN GLAZE OF ICE COULD FORM ACROSS OVERPASSES AND BRIDGES IN PARTICULAR. AS YOU HEAD OUT TO ENJOY THE NEW YEAR FESTIVITIES...CAUTION IS ADVISED. CHECK BACK TO STAY ALERT AND UP TO DATE WITH ANY WEATHER CHANGES. && .PRELIMINARY POINT TEMPS/POPS... FRIONA 20 11 22 17 32 / 30 40 20 10 20 TULIA 22 13 22 19 32 / 30 40 10 10 20 PLAINVIEW 23 14 23 19 32 / 30 40 10 10 20 LEVELLAND 24 16 24 19 32 / 40 50 20 20 20 LUBBOCK 25 16 25 20 32 / 40 50 20 20 20 DENVER CITY 27 18 25 20 33 / 40 50 20 20 30 BROWNFIELD 27 18 25 20 33 / 40 50 20 20 30 CHILDRESS 28 18 25 22 34 / 20 40 10 10 20 SPUR 28 18 25 22 33 / 30 50 20 20 30 ASPERMONT 30 20 27 24 36 / 20 40 20 20 30 && .LUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 07/29/07
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
541 AM CST Tue Dec 30 2014 .DISCUSSION... && .AVIATION... Strong front has moved through the region with a gusty N/NE wind in its wake... gusts should continue through the day. Low clouds have reached most TAF sites and will remain through the day with low MVFR/IFR conditions. Expect a wintry precipitation to develop with freezing rain... freezing drizzle... and sleet along with some fog to reduce vsbys. && .PREV DISCUSSION... /ISSUED 512 AM CST Tue Dec 30 2014/ DISCUSSION...As of 5:00 AM CST Tuesday...Sfc obs indc that the Arctic Front has made it to the Trans Pecos...and continues to surge south. Low clouds have quickly filled in behind the front with low overcast past Wink per sfc obs and satl imagery. Winter weather will be the rule into the New Year. Mild air will override the cold low level airmass. With the lack of jet dynamics isentropic lift will lead to periods of light freezing rain and sleet right thru Wednesday aftn...and possibly into New Years Day. The HRRR model is indc precipitation moving thru the Permian Basin and Southeast New Mexico this morning and moving south of the Pecos River by late morning. Temps will slowly fall through the day with below freezing temps thru New Years Eve. Due to the extended nature of this event and the substantial impacts to holiday travel have upgraded the Winter Storm Watch to a Winter Storm Warning. The warning will continue thru Wed aftn for West Texas and Southeast New Mexico...except for the Presidio Valley where temps could be a little warmer. Strong sfc pressure gradient will lead to high winds thru Guadalupe Pass...the High Wind Watch has been upgraded to a High Wind Warning continuing into Wednesday morning. A combination of gusty winds and very cold temperatures could lead to wind chill values in the single digits in the Plains tonight...with dangerous wind chill values as low as -10F in the Guadalupe Mtns. An upper low over SoCal will move slowly east into Southeast New Mexico Friday night. Light freezing rain and sleet could continue into New Years morning. It is possible that the Winter Storm Warning might need to be extended into New Years morning. Milder air should change the precipitation to rain New Years aftn. However...the ECMWF is showing a deeper cold airmass moving back into the CWA bringing a chance of snow Thursday night...and a chance of a rain/snow mix Friday and Friday night. As the upper low moves east of the CWA...the upcoming weekend will be dry but cool. Southwest flow sfc and aloft will bring dry weather along with a warming trend the beginning of next week. Strobin && .MAF WATCHES/WARNINGS/ADVISORIES... NM...WINTER STORM WARNING until 5 PM MST Wednesday FOR THE FOLLOWING ZONES... Central Lea County...Eddy County Plains... Guadalupe Mountains of Eddy County...Northern Lea County... Southern Lea County. TX...WINTER STORM WARNING until 6 PM CST /5 PM MST/ Wednesday FOR THE FOLLOWING ZONES... Andrews...Big Bend Area...Borden... Crane...Davis/Apache Mountains Area...Dawson...Ector... Gaines...Glasscock...Guadalupe Mountains...Howard... Loving...Marfa Plateau...Martin...Midland...Mitchell... Pecos...Reagan...Reeves County and Upper Trans Pecos... Scurry...Terrell...Upton...Van Horn and Highway 54 Corridor...Ward...Winkler. HIGH WIND WARNING until 8 AM MST Wednesday FOR THE FOLLOWING ZONES... Guadalupe Mountains. && $$ Follow us on Facebook and Twitter at: http://facebook.com/NWSMidland http://twitter.com/NWSMidland Check us out on the internet at: http://weather.gov/midland
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
523 AM CST TUE DEC 30 2014 .UPDATE...SECOND UPDATE TO EXPAND DENSE FOG ADVISORY FARTHER WEST AND SOUTH BASED ON SATELLITE AND WEB CAM TRENDS. THIS ALSO LINES UP WELL WITH HRRR EXPANSION OF FOG. && .PREV DISCUSSION... /ISSUED 443 AM CST TUE DEC 30 2014/ UPDATE...QUICK UPDATE TO ISSUE DENSE FOG ADVISORY FOR I-35 CORRIDOR FROM COMAL TO WILLIMSON COUNTY EASTWARD. THIS IS BASED ON SEVERAL WEBCAMS AND OBS INDICATING DENSE FOG. THERE IS ALSO THE POTENTIAL FOR PATCHY TO AREAS OF DENSE FOG SOUTH AND WEST OF THE ADVISORY AREA THROUGH THE MORNING. PREV DISCUSSION... /ISSUED 401 AM CST TUE DEC 30 2014/ SHORT TERM (TODAY THROUGH WEDNESDAY)...AREAS OF LOW STRATUS AND FOG HAVE FORMED ACROSS EASTERN AREAS AS WELL AS ALONG THE RIO GRANDE EARLY THIS MORNING. THE FOG AND CLOUDS WILL CONTINUE TO EXPAND INTO THE I-35 CORRIDOR AND PORTIONS OF THE HILL COUNTRY THROUGH THE MORNING HOURS. THE MUCH ADVERTISED ARCTIC AIRMASS HAS MOVED THROUGH THE HILL COUNTRY AND INTO WEST TEXAS. THE AIRMASS IN RELATIVELY DENSE BEHIND A 1055MB HIGH ANALYZED UP IN MONTANA. THE AIRMASS WILL GRADUALLY FILTER INTO SOUTH-CENTRAL TEXAS TODAY AND TONIGHT. ISENTROPIC ASCENT ABOVE THE SHALLOW...COLD AIRMASS WELL DEVELOP TONIGHT AND GRADUALLY STRENGTHEN WEDNESDAY AND WEDNESDAY NIGHT. INITIALLY THICK CLOUDS WILL RESULT FROM THIS...WITH ONLY PATCHY DRIZZLE AND PATCHY LIGHT RAIN DEVELOPING ACROSS THE WESTERN CWA TONIGHT AND EXPANDING EAST ON WEDNESDAY. THE GFS CONTINUES TO BE DRIER IN THE LOWEST LEVELS TODAY THROUGH WEDNESDAY...TAKING LONGER TO MOISTEN. HOWEVER FORECAST SOUNDINGS FROM THE HRRR/ARW/NMM AS WELL AS NAM12 ARE NOT QUITE AS AGGRESSIVE WITH THIS DRY LAYER AND MOISTENS FASTER. HAVE FOLLOWED SLIGHTLY CLOSER TO THE LATTER. THIS COULD POTENTIALLY RESULT IN PATCHY FREEZING DRIZZLE AND FREEZING LIGHT RAIN ALONG AND NORTH OF A PANDALE TO LEAKY TO JOHNSON CITY TO BURNET LINE EARLY WEDNESDAY MORNING. QPF AMOUNTS SHOULD BE VERY LIGHT...AND GIVEN GROUND TEMPS AND PATCHY COVERAGE IMPACTS SHOULD BE LIMITED TO ELEVATED SURFACES WITH MINIMAL TRAVEL IMPACTS. ON WEDNESDAY VERY LITTLE DIURNAL TEMPERATURE RANGE IS EXPECTED... WITH HIGHS ONLY CLIMBING INTO THE MID 30S ACROSS THE HILL COUNTRY (WITH A FEW ISOLATED HILL COUNTRY SPOTS REMAINING IN THE LOW 30S)...UPPER 30S ALONG THE I-35 CORRIDOR AND LOW 40S ALONG THE RIO GRANDE AS WELL AS FAR SOUTHERN/SOUTHEAST AREAS. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... .FREEZING RAIN WITH TRAVEL IMPACTS POSSIBLE LATE NEW YEARS EVE INTO NEW YEARS DAY ACROSS THE HILL COUNTRY. WINTER STORM WATCH POSTED... THE UPPER LEVEL LOW ACROSS SOUTHERN CALIFORNIA IS FORECAST TO MOVE EAST INTO ARIZONA NEW YEARS EVE NIGHT INTO NEW YEARS DAY. THE ISENTROPIC UPGLIDE OVER THE COLD AIRMASS STRENGTHENS WEST TO EAST DURING THIS TIME. SEVERAL MODELS HAVE BEEN INDICATING FOR A FEW RUNS NOW A MID AND UPPER LEVEL SHORTWAVE IN THE SOUTHWEST FLOW ALOFT MOVING OUT OF MEXICO AND INTO WEST-CENTRAL TEXAS AND THE HILL COUNTRY LATE WEDNESDAY NIGHT AND THURSDAY. GFS AND ECMWF BOTH SHOW ENHANCED BAND OF QPF CLIPPING THE HILL COUNTRY...ALONG WITH SREF OUTPUT. CONFIDENCE CONTINUES TO GROW IN FREEZING RAIN EVENT LATE WEDNESDAY NIGHT THROUGH MIDDAY THURSDAY ACROSS AT LEAST THE HILL COUNTRY. THE WARM CLOUD LAYER DEPTH IS INCREASING DURING THIS TIME...BUT CAN NOT COMPLETELY RULE OUT SLEET MIXING IN ACROSS THE NORTHERN HILL COUNTRY AS WELL. GIVEN HOLIDAY TRAVEL SENSITIVITY... AND AFTER COORDINATION WITH SURROUNDING WFOS...WE HAVE DECIDED TO ISSUE A WINTER STORM WATCH FOR THE HILL COUNTRY...ALONG AND NORTH OF A VAL VERDE TO BANDERA TO BURNET COUNTY LINE. IF TEMPS AND ENHANCEMENT IN QPF VERIFY...THERE COULD BE A BAND ACROSS THE NORTHERN HILL COUNTRY OF HIGHER ICE ACCUMULATION AMOUNTS. FARTHER EAST ALONG THE I-35 CORRIDOR...TEMPERATURES WILL BE VERY CLOSE TO FREEZING EARLY THURSDAY MORNING. ALTHOUGH THESE COUNTIES ARE NOT CURRENTLY IN THE WATCH...THE FREEZING RAIN LINE IS FORECAST TO REACH A HELOTES TO WIMBERLY TO GEORGETOWN LINE. ANY TRENDS DOWNWARD IN THE TEMP FORECAST...OR WET-BULB COOLING...COULD PUSH THIS LINE TOWARDS THE AUSTIN AND NORTHERN SAN ANTONIO METRO AREAS. THOSE WITH TRAVEL PLANS NEW YEARS EVE NIGHT INTO NEW YEARS DAY ALONG THE INTERSTATE 35 CORRIDOR SHOULD CLOSELY MONITOR FOR ANY FORECASTS UPDATES. MODELS ARE SLIGHTLY SLOWER WITH HOW FAST THE UPPER LEVEL LOW EJECTS OUT INTO THE PLAINS FROM RUNS A FEW DAYS AGO. THE UPPER LEVEL LOW MOVES ACROSS SOUTHERN NEW MEXICO FRIDAY AND NORTHEAST THROUGH WEST TEXAS FRIDAY NIGHT INTO SATURDAY MORNING. GOOD CHANCES FOR RAIN WILL CONTINUE ACROSS THE REGION THURSDAY NIGHT THROUGH FRIDAY NIGHT. THE WARM CLOUD LAYER CONTINUES TO WARM FURTHER WITH SLIGHT MODIFICATION IN THE COLD AIRMASS BELOW. PRECIP WILL REMAIN ALL LIQUID DURING THIS TIME (ALTHOUGH MAY HAVE TO WATCH CLOSELY ACROSS FAR NORTHERN AREAS OF THE CWA THURSDAY NIGHT). IN ADDITION...THERE WILL ALSO BE THE POTENTIAL FOR EMBEDDED THUNDER THURSDAY NIGHT THROUGH FRIDAY NIGHT AS ELEVATED LAPSE RATES STEEPEN...AND HAVE CONTINUED THIS IN THE FORECAST. CLEARING AND DRYING TAKES PLACE DOES EVENTUALLY TAKE PLACE WEST TO EAST SATURDAY WITH HIGHS TEMPS WARMING BACK TO TOWARDS SEASONABLE LEVELS OVER THE WEEKEND AND INTO EARLY NEXT WEEK. JR && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 52 34 38 34 40 / 10 10 20 30 60 AUSTIN BERGSTROM INTL AIRPORT 52 35 38 34 40 / 10 10 20 30 60 NEW BRAUNFELS MUNI AIRPORT 54 36 38 34 39 / 10 10 20 30 50 BURNET MUNI AIRPORT 48 30 36 29 37 / 10 10 20 30 60 DEL RIO INTL AIRPORT 54 36 41 33 44 / 10 40 30 30 20 GEORGETOWN MUNI AIRPORT 49 32 36 31 38 / 10 10 20 30 60 HONDO MUNI AIRPORT 56 36 39 33 42 / 10 20 20 30 40 SAN MARCOS MUNI AIRPORT 53 35 38 34 40 / 10 10 20 30 60 LA GRANGE - FAYETTE REGIONAL 55 36 41 36 42 / 10 10 20 30 50 SAN ANTONIO INTL AIRPORT 55 36 39 35 41 / 10 10 20 30 50 STINSON MUNI AIRPORT 56 38 39 36 41 / 10 10 20 30 50 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY MORNING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE. DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR THE FOLLOWING COUNTIES: ATASCOSA...BANDERA...BASTROP...BEXAR...BLANCO...BURNET... CALDWELL...COMAL...DIMMIT...FAYETTE...FRIO...GILLESPIE...GONZALES... GUADALUPE...HAYS...KENDALL...KERR...LEE...LLANO...MEDINA...TRAVIS... UVALDE...WILLIAMSON...WILSON...ZAVALA. && $$ MESOSCALE/AVIATION...05 SYNOPTIC/GRIDS...76
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
512 AM CST Tue Dec 30 2014 .DISCUSSION...As of 5:00 AM CST Tuesday...Sfc obs indc that the Arctic Front has made it to the Trans Pecos...and continues to surge south. Low clouds have quickly filled in behind the front with low overcast past Wink per sfc obs and satl imagery. Winter weather will be the rule into the New Year. Mild air will override the cold low level airmass. With the lack of jet dynamics isentropic lift will lead to periods of light freezing rain and sleet right thru Wednesday aftn...and possibly into New Years Day. The HRRR model is indc precipitation moving thru the Permian Basin and Southeast New Mexico this morning and moving south of the Pecos River by late morning. Temps will slowly fall through the day with below freezing temps thru New Years Eve. Due to the extended nature of this event and the substantial impacts to holiday travel have upgraded the Winter Storm Watch to a Winter Storm Warning. The warning will continue thru Wed aftn for West Texas and Southeast New Mexico...except for the Presidio Valley where temps could be a little warmer. Strong sfc pressure gradient will lead to high winds thru Guadalupe Pass...the High Wind Watch has been upgraded to a High Wind Warning continuing into Wednesday morning. A combination of gusty winds and very cold temperatures could lead to wind chill values in the single digits in the Plains tonight...with dangerous wind chill values as low as -10F in the Guadalupe Mtns. An upper low over SoCal will move slowly east into Southeast New Mexico Friday night. Light freezing rain and sleet could continue into New Years morning. It is possible that the Winter Storm Warning might need to be extended into New Years morning. Milder air should change the precipitation to rain New Years aftn. However...the ECMWF is showing a deeper cold airmass moving back into the CWA bringing a chance of snow Thursday night...and a chance of a rain/snow mix Friday and Friday night. As the upper low moves east of the CWA...the upcoming weekend will be dry but cool. Southwest flow sfc and aloft will bring dry weather along with a warming trend the beginning of next week. Strobin && .PRELIMINARY POINT TEMPS/POPS... ANDREWS TX 29 20 24 22 / 60 60 50 30 BIG SPRING TX 31 20 24 24 / 60 60 50 30 CARLSBAD NM 31 23 25 23 / 40 60 50 30 DRYDEN TX 41 32 32 29 / 50 60 50 20 FORT STOCKTON TX 32 20 29 25 / 50 60 60 20 GUADALUPE PASS TX 26 14 21 19 / 40 50 60 20 HOBBS NM 29 21 24 21 / 60 60 50 30 MARFA TX 37 19 31 22 / 30 40 50 20 MIDLAND INTL AIRPORT TX 30 19 25 23 / 60 60 50 30 ODESSA TX 29 20 25 23 / 60 60 50 30 WINK TX 32 28 29 26 / 40 60 50 20 && .MAF WATCHES/WARNINGS/ADVISORIES... NM...WINTER STORM WARNING until 5 PM MST Wednesday FOR THE FOLLOWING ZONES... Central Lea County...Eddy County Plains... Guadalupe Mountains of Eddy County...Northern Lea County... Southern Lea County. TX...WINTER STORM WARNING until 6 PM CST /5 PM MST/ Wednesday FOR THE FOLLOWING ZONES... Andrews...Big Bend Area...Borden... Crane...Davis/Apache Mountains Area...Dawson...Ector... Gaines...Glasscock...Guadalupe Mountains...Howard... Loving...Marfa Plateau...Martin...Midland...Mitchell... Pecos...Reagan...Reeves County and Upper Trans Pecos... Scurry...Terrell...Upton...Van Horn and Highway 54 Corridor...Ward...Winkler. HIGH WIND WARNING until 8 AM MST Wednesday FOR THE FOLLOWING ZONES... Guadalupe Mountains. && $$ 72/33 Follow us on Facebook and Twitter at: http://facebook.com/NWSMidland http://twitter.com/NWSMidland Check us out on the internet at: http://weather.gov/midland
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AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1152 PM EST MON DEC 29 2014 .SYNOPSIS... COLD SURFACE HIGH PRESSURE WILL CONTINUE TO WEDGE DOWN FROM THE NORTH ALONG THE APPALACHIANS TONIGHT WHILE A WEAK UPPER LEVEL DISTURBANCE IS EXPECTED TO PASS FROM WEST TO EAST ACROSS THE AREA TONIGHT THROUGH EARLY TUESDAY. VERY LIGHT PRECIPITATION ASSOCIATED WITH THIS FEATURE IS EXPECTED TO CHANGE OVER TO SNOW ACROSS THE NORTHERN PORTION OF THE REGION...WITH ACCUMULATIONS OF AN INCH OR LESS...MAINLY ALONG AND NORTH OF U.S. 460. DRY BUT CONTINUED COLD HIGH PRESSURE WILL BEGIN TO PUSH IN FROM THE WEST LATER TUESDAY AND LAST UNTIL LATE IN THE WEEK. && .NEAR TERM /THROUGH TUESDAY/... AS OF 635 PM EST MONDAY... MADE A FEW MINOR ADJUSTMENTS TO EXISTING SET OF GRIDS TO BUMP UP PROBABILITY OF PRECIPITATION TO ACCOUNT FOR WIDESPREAD RAIN AND DRIZZLE NOW FALLING ACROSS MUCH OF THE NEW RIVER VALLEY NORTH TOWARD THE ALLEGHANY HIGHLANDS. DESPITE AREAL EXTENT OF PRECIPITATION...AMOUNTS CONTINUE TO BE LIGHT...GENERALLY ONLY AROUND 0.01 INCH/PER HOUR. LATEST UPPER-AIR SOUNDING...RELEASED ABOUT 30 MINUTES AGO...SHOWS LOWEST 3K FEET AGL STILL ABOVE FREEZING AND NEARLY SATURATED...SO IT WILL TAKE MUCH OF THE EVENING...PERHAPS INTO THE EARLY MORNING HOURS...TO DRIVE SNOW LEVELS DOWN FROM HIGHEST RIDGES TO MOUNTAIN VALLEY AREAS...CONSISTENT WITH PREVIOUS FORECAST THINKING. THEREFORE...SNOWFALL TOTALS STILL NOT EXPECTED TO BECOME PROBLEMATIC AS THE NIGHT PROGRESSES...ESPECIALLY CONSIDERING CURRENT WARM GROUND CONDITIONS AND VERY LIGHT FALL RATES. ALSO MADE A FEW TWEAKS TO HOURLY TEMPS/DEW POINT GRIDS TO REFLECT LATEST MESONET OBSERVATIONS...OTHERWISE REST OF FORECAST FOR TONIGHT STILL LOOKS RIGHT ON TARGET. AS OF 350 PM EST MONDAY... TRICKY FCST OVERNIGHT IN REGARDS TO THE AMOUNTS AND LOCATIONS OF VERY LIGHT PCPN AS A WEAK UPPER WAVE PASSES OVER THE DEEPENING COLD AIR DAMMING WEDGE AS COLD SFC HIGH PRESSURE SPILLS DOWN FROM THE NORTH. MODEL GUIDANCE ALL QUITE DIFFERENT WITH MAIN OPERATIONAL NCEP MODELS TRENDING UPWARD SOMEWHAT WITH AS MUCH AS A QUARTER TO TWO THIRDS OF AN INCH LIQUID EQUIV...MAINLY OVER THE WESTERN PORTIONS. EVEN ORIGINALLY DRIER GFS NOW AS MUCH AS FOUR TENTHS OF AN INCH OVER THE ALLEGHANY HIGHLANDS. MEANWHILE CONVECTIVE-ALLOWING MODELS GENERALLY LESS THAN TWO TENTHS OF AN INCH. AM LEANING ON THE LIGHT SIDE OF THE QPF OPTIONS...MORE IN LINE WITH IDEA OF MOST OF THE HRRR RUNS...AND POSSIBILITY THAT MORE OF THE PCPN ACTUALLY ENDS UP BACK ACROSS THE FOOTHILLS AND PIEDMONT AGAIN. AM LEAVING SOME VERY LOW LIKELY POPS FOR TONIGHT ACROSS PARTS OF THE MOUNTAINS...WITH HIGHER CHANCE POPS NOW ACROSS THE FOOTHILLS. THE ISSUE OF MOISTURE DEPTH IS STILL CONCERN AS WELL...AND WHILE I DID NOT INCLUDE ANY DRIZZLE IN THE GRIDS...THERE COULD VERY WELL BE PERIODS OF TIME AND PORTIONS OF THE AREA WHERE WE SEE MORE DRIZZLE DUE TO LACK OF ICE CRYSTAL GROWTH ALOFT. THIS WOULD CUT DOWN ON ANY OF THE ALREADY LIGHT SNOW ACCUMS IF AND WHERE THIS HAPPENS. WARM NOSE DOES NOT SEEM TO BE PRESENT IN ANY MODEL SOUNDINGS...SO GOING WITH EITHER RAIN OR SNOW...AND SO SFC TEMPS WILL BE THE KEY TO THAT CHANGEOVER. AS FAR AS THE TEMPS GO...ALREADY GETTING COLDER THIS AFTERNOON THAN WE EARLIER ANTICIPATED...AND SOME HIGHER ELEVATIONS HAVE REPORTS SOME VERY LIGHT SNOW. THUS LOWERED TEMPS THROUGH EVENING AND OVERNIGHT A FEW DEGREES FROM PREVIOUS FORECAST WHERE WEDGE IS EXPECTED TO BE THE STRONGEST...AND THIS RESULTS IN A SLIGHTLY EARLIER CHANGEOVER FROM LIGHT RAIN TO LIGHT SNOW...BUT EXCEPT FOR HIGHER ELEVATIONS...THIS WILL STILL BE AFTER MIDNIGHT. BOTTOM LINE IS ONLY VERY LIGHT AMOUNTS OF SNOW ACCUM EXPECTED LATE TONIGHT AND IN THE EARLY MORNING HOURS TUESDAY...AND IT WILL LIKELY HAVE TROUBLE STICKING AS WELL EXCEPT FOR HIGHEST ELEVATIONS. HAVE DUSTING TO LESS THAN AN INCH GENERALLY NORTH OF U.S. 460...AND DOWN THE BLUE RIDGE TO NEAR MEADOWS OF DAN. MAYBE AN INCH TO ALMOST TWO ALONG HIGHEST RIDGES OF ALLEGHANY HIGHLANDS AND ALONG BLUE RIDGE PARKWAY NORTH OF PEAKS OF OTTER. MOST ROADS NOT EXPECTED TO SEE ANY ACCUMULATION. ANY LINGERING PCPN EVAPORATES QUICKLY BY MIDDAY TUESDAY AS SHORT WAVE PASSES BY AND DRIER AIR FROM NORTH CONTINUES TO FILTER IN. WESTERLY FLOW AT RIDGE TOP LEVEL DEVELOPS BUT VERY WEAK FLOW AND LITTLE MOISTURE TO WORK WITH SO NO ISSUES WITH ANY UPSLOPE SNOW SHOWERS IN FAR WEST IT APPEARS. MAX TEMPS MAY BE TRICKY WITH SOME SUNSHINE LATE IN THE DAY...BUT THIS COULD BE TOO LATE FOR LOW SUN ANGLE TO HAVE MUCH IMPACT...SO FOR NOW GOING ON COLD SIDE OF GUIDANCE WITH ONLY ABOUT A 5-7 DEGREE RISE FROM OVERNIGHT LOWS. ABOVE FREEZING BY LATE MORNING SO ANY MINOR AMOUNTS OF SNOW THAT DOES FALL WILL BE GONE BY NOON MOST LIKELY. FINALLY...COLD WEDGE WILL KEEP SOME AREAS OF FOG AND LOW CEILINGS AROUND...MOST ESPECIALLY NEAR THE BLUE RIDGE...BUT ALSO SOME OF THE MTN VALLEYS AS WELL...SO BLANKED THE FOOTHILLS AND WESTWARD WITH PATCHY FOG THROUGH TOMORROW MORNING IN THE FORECAST GRIDS BUT THIS MAY LINGER THROUGH MUCH OF THE DAY IN SPOTS UNTIL THE WEAK WESTERLY FLOW CAN PUSH EAST. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... AS OF 200 PM EST MONDAY... A LARGE AREA OF HIGH PRESSURE WILL BUILD SOUTH FROM THE ROCKIES LATE TUESDAY...THEN INTO THE SOUTHEAST U.S. BY THURSDAY EVENING KEEPING DRY WEATHER FOR OUR AREA DURING THIS PORTION OF THE FORECAST. ADJUSTED TEMPS DOWN A FEW DEGREES WEDNESDAY MORNING AND WEDNESDAY AFTERNOON UNDER GOOD COLD AIR ADVECTION. BY THURSDAY MORNING MODELS ARE IN GOOD AGREEMENT THAT SFC HIGH NOSES INTO OUR AREA ALLOWING VALLEY WINDS TO DIMINISH. THIS COMBINED WITH THE DRY AIR MASS IN PLACE SHOULD ALLOW TEMPS TO DROP BELOW GUIDANCE VALUES. THE EXCEPTION WILL BE ON THE RIDGETOPS WHERE 850MB WINDS WILL KEEP TEMPS WARMER. HEIGHTS RISE ON THURSDAY AS AN UPPER RIDGE BEGINS TO BUILD IN THE CENTRAL U.S. IN ADVANCE OF A SOUTHWEST U.S. UPPER LOW. THIS...COMBINED WITH DOWNSLOPING WINDS...SHOULD ALLOW FOR A NICE RECOVERY IN TEMPS THURSDAY. WENT A DEGREE OR TWO ABOVE GUIDANCE FOR HIGHS. ONLY OTHER CHANGE TO THE FORECAST WAS TO INCREASE THE WINDS ABOVE 3500 FEET WEDNESDAY AND THURSDAY AS A SWIFT MOVING NORTHERN STREAM SHORTWAVE PASSES THROUGH THE EASTERN GREAT LAKES THROUGH NEW ENGLAND DURING THIS TIME. && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 235 PM EST MONDAY... DRY AND SEASONABLY COOL WEATHER IS EXPECTED OVER THE BLACKSBURG FORECAST AREA FRIDAY MORNING AS A WEAK SHORT WAVE IN NORTHERN STREAM SCOOTS EAST THROUGH NEW ENGLAND...WITH COOL HIGH PRESSURE BUILDING SOUTHWESTWARD IN ITS WAKE. HOWEVER...MUCH OF THE REST OF THE LONG TERM FORECAST FROM FRIDAY AFTERNOON INTO MONDAY APPEARS TO BE MUCH MORE UNCERTAIN...WITH SIGNIFICANT AND PERSISTENT DISPARITY EXISTING BETWEEN THE LONGER- TERM MODELS IN REFLECTING STRENGTH AND PLACEMENT OF NORTHERN STREAM...AND ITS INFLUENCE ON SOUTHERN STREAM CLOSED LOW SOUTH OF THE FOUR CORNERS AREA ON FRIDAY AFTERNOON THAT IS FORECAST TO GRADUALLY LIFT NORTHEAST AND FILL AS IT PROGRESSES FROM THE SOUTHERN PLAINS UP THROUGH THE OHIO VALLEY OVER THE WEEKEND. ECMWF MAINTAINS A MORE PERSISTENT CLOSED UPPER LOW THAT IS MUCH LESS AMPLIFIED...YET LESS PROGRESSIVE AND FURTHER SOUTH...RESULTING IN INCREASING ISENTROPIC LIFT AND RAIN MOVING INTO AT LEAST THE SOUTHWESTERN HALF OF THE BLACKSBURG FORECAST AREA BY/DURING FRIDAY AFTERNOON...BUT NOT ENDING UNTIL PASSAGE OF OPENING/WEAKENING UPPER TROF ON SUNDAY NIGHT. GFS...WHICH REFLECTS A MORE AMPLIFIED...YET EVENTUALLY MORE PROGRESSIVE AND NORTHERN SYSTEM PLACEMENT...HOLDS BACK RAIN SHIELD UNTIL SATURDAY DUE TO INFLUENCE OF LARGER AND STRONGER DRY SURFACE HIGH PRESSURE SYSTEM OVER NEW ENGLAND. GFS ALSO THE COLDER OF THE LONGER RANGE SOLUTIONS...SINCE STRONGER SURFACE RIDGE TO NORTHEAST WOULD LOCK COOL-WEDGE IN PLACE OVER THE BLACKSBURG FORECAST AREA. HOWEVER...BEING MORE PROGRESSIVE...RAIN EVENT ENDS A BIT EARLIER THAN ECMWF SOLUTION...ON SUNDAY AFTERNOON WITH PASSAGE OF UPPER TROF...BUT WITH PERHAPS SOME COLD ADVECTION UPSLOPE PRECIPITATION CONTINUING ACROSS THE WESTERN FLANKS OF THE APPALACHIANS UNTIL AROUND DAYBREAK MONDAY. BOTH MODELS HAVE BEEN INCONSISTENT IN TIMING AND PLACEMENT OF SYSTEM THOUGH THIS TIME FRAME FOR AT LEAST THE PAST SEVERAL RUNS...WHICH IS NOT ALL THAT SURPRISING CONSIDERING ACTIVE NORTHERN STREAM CLASHING WITH INITIALLY CLOSED AND STAGNANT SOUTHERN STREAM SYSTEM...SO MODEL BLEND/ENSEMBLE APPROACH BEST TO APPLY FOR LONG TERM FORECAST UNTIL CONFIDENCE INCREASES IN MOVING TOWARD ANY PARTICULAR SOLUTION. NEITHER MODEL INDICATING THAT THICKNESSES WILL BE ESPECIALLY CRITICAL FOR P-TYPE ISSUES...MEANING A MAINLY WET RATHER THAN WHITE FORECAST OVER THE WEEKEND. HOWEVER...IF COLDER GFS SOLUTION VERIFIES...THICKNESSES MAY BE CLOSE ENOUGH TO CRITICAL VALUES NORTH OF HIGHWAY 64 TO WARRANT AT LEAST A NOMINAL INSERTION OF A P-TYPE MIX DURING TIME OF PRECIPITATION ONSET...AND PERHAPS FOLLOWING PASSAGE OF MAIN SYSTEM IN THE NORTHWESTERN MOUNTAINS ON SUNDAY NIGHT PROVIDED THAT POST FRONTAL COLD ADVECTION IS SUFFICIENTLY STRONG. REGARDLESS OF TIMING AND PLACEMENT DIFFERENCES...ALL LONGER RANGE MODELS INDICATE THAT MONDAY WILL BE DRY FOLLOWING PASSAGE OF THE MAIN UPPER SYSTEM...WITH ANY ADDITION SOUTHERN STREAM ENERGY LIKELY TO BE DEFLECTED TO OUR SOUTH AS NORTHERN STREAM TROFING GRADUALLY STRENGTHENS AND AMPLIFIES FROM THE UPPER GREAT LAKES EAST INTO THE NORTHEASTERN PORTION OF THE NATION FROM MONDAY INTO THE MID WEEK PERIOD. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... AS OF 1150 PM EST MONDAY... IFR TO LIFR CONDITIONS EXPECTED TO CONTINUE AT ALL AIRPORTS THROUGH AT LEAST TONIGHT...AND FOR WESTERN AIRPORTS EVEN INTO EARLY PART OF TUESDAY...UNDER THE INFLUENCE OF COLD AIR DAMMING WHICH IS ONLY STRENGTHENING WITH TIME. ALL AIRPORTS EXCEPT FOR KDAN SHOULD SEE SOME VERY LIGHT RAIN CHANGE TO LIGHT SNOW OVERNIGHT...BUT NOT EXPECTED TO STICK MUCH AT ALL EXCEPT FOR THE HIGHER ELEVATION AIRPORTS SUCH AS KLWB...AND KBCB. NOT SURE IT WILL BE COLD ENOUGH TO REALLY ACCUMULATE AT KBLF AND KROA OR KLYH. KDAN LIKELY WILL NOT EVEN SEE CHANGEOVER. IN ANY CASE...SNOW AMOUNTS WOULD ONLY APPROACH AN INCH IN THE WORSE-CASE SCENARIO. LOW CONFIDENCE FOR WHEN CONDITIONS MAY BEGIN TO BREAK OUT AND LIFT ON TUESDAY. MORE CONFIDENT THAT KROA...KLYH AND KDAN WILL IMPROVE TO VFR BY TUESDAY AFTERNOON AS DRIER AIR CONTINUES TO FILTER DOWN FROM NORTH. CLEARING WILL CONTINUE IN THE AFTERNOON AND EVENING. EVEN MOUNTAIN TAF SITES WILL IMPROVE TO VFR. EXTENDED DISCUSSION... A LARGE AREA OF HIGH PRESSURE WILL START TO NOSE INTO THE AREA FROM THE WEST LATER TUESDAY INTO WEDNESDAY. VFR WILL THEN PREVAIL THROUGH AT LEAST THURSDAY CONDITIONS DETERIORATE THE WEEKEND. THE NEXT LOW PRESSURE SYSTEM TO AFFECT THE AREA WILL COME FROM THE SOUTHWEST..DEVELOPING ALONG THE TEXAS GULF COAST FRIDAY...THEN MOVING NORTHEAST ACROSS THE MID ATLANTIC REGION FOR THE WEEKEND. THIS SYSTEM LOOKS LIKE IT WILL PRODUCE A MULTI-DAY PERIOD OF SUB-VFR CONDITIONS...BEGINNING AS EARLY AS FRIDAY NIGHT...AND LINGERING THROUGH SUNDAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...SK NEAR TERM...SK/WERT SHORT TERM...PH LONG TERM...WERT AVIATION...AMS/WERT
AREA FORECAST DISCUSSION
NWS TUCSON AZ
945 PM MST WED DEC 31 2014 .SYNOPSIS...RAIN AND SNOW WILL CONTINUE ACROSS MUCH OF THE AREA INTO THURSDAY. SNOW LEVELS WILL FALL TO THE VALLEY FLOORS IN SOME LOCATIONS TONIGHT. ELEVATIONS ABOVE 4000 FEET CAN EXPECT ACCUMULATING SNOW BY THURSDAY MORNING WITH SIGNIFICANT SNOW IN THE MOUNTAINS. A SECONDARY DISTURBANCE WILL BRING A FEW SNOW SHOWERS THURSDAY NIGHT INTO FRIDAY MORNING. A HARD FREEZE IS LIKELY FOR THE TUCSON METRO AREA THURSDAY NIGHT AND PERHAPS AGAIN FRIDAY NIGHT. DRY CONDITIONS WITH A WARMING TREND WILL OCCUR THIS WEEKEND AND INTO NEXT WEEK. && .DISCUSSION...KEMX WSR-88D CONTINUES TO INDICATE NUMEROUS MAINLY 30-35 DBZ ECHOES ACROSS MUCH OF PIMA/SRN PINAL/SANTA CRUZ/FAR WRN COCHISE COUNTY VALID 0440Z. THESE PRECIP ECHOES WERE MOVING NEWD AROUND 10-15 KTS. BASED ON VARIOUS OBSERVATIONS...THE BEST ESTIMATE FOR SNOW LEVELS IN THE FOOTHILLS ADJACENT TUCSON IS 3000-3500 FEET... AND 4000-4500 FEET ACROSS ERN SANTA CRUZ COUNTY. THERE HAVE BEEN SEVERAL REPORTS OF SNOW MIXED WITH RAIN ABOVE 3000 FEET VIA SOCIAL MEDIA. MOUNT LEMMON FIRE DEPARTMENT (ELEV ABOUT 7800 FT) REPORTED A SNOW ACCUMULATION OF 7.0 INCHES VALID 940 PM MST. 542 DM LOW CENTERED OVER FAR WEST CENTRAL AZ WILL MOVE NEWD INTO NORTH CENTRAL AZ AROUND DAYBREAK THUR. PRECIP WILL CONTINUE TO MOVE EWD THE REST OF TONIGHT...AND THE 01/01Z RUC HRRR DEPICTS THE BULK OF PRECIP TO END FROM TUCSON WWD AROUND 01/08Z OR SO. HAVE NOTED THAT THE HRRR DEPICTS PRECIP TO END ACROSS ERN SECTIONS SHORTLY THEREAFTER...OR BY AROUND DAYBREAK THUR. FOR THE OFFICIAL FORECAST UPDATE...SNOW LEVELS WERE LOWERED TO REFLECT THE ONGOING CONDITIONS AS NOTED ABOVE. AREAS OF FOG WERE ADDED FOR THE REST OF TONIGHT AND INTO THUR MORNING FOR ERN PIMA COUNTY...SANTA CRUZ COUNTY AND THE UPPER SAN PEDRO RIVER VALLEY. BASED ON RECEIPT OF THE 01/00Z NAM/GFS MOS GUIDANCE...OPTED TO CHANGE THE FREEZE WATCH FOR THE TUCSON METRO AREA AND ADJOINING LOCALES WEST-TO-NORTHWEST OF TUCSON TO A HARD FREEZE WARNING LATE THUR NIGHT/EARLY FRI MORNING. THE OTHER WINTER STORM WARNINGS...WINTER WEATHER ADVISORIES...AND FREEZE WATCH CONTINUE UNCHANGED. PRECIP THUR AFTERNOON SHOULD BE CONFINED TO ERN SECTIONS...AND ANY LINGERING SHOWERS SHOULD BE MAINLY NEAR THE NEW MEXICO BORDER FRI. PLEASE REFER TO THE ADDITIONAL SECTIONS FOR FURTHER DETAIL. && .AVIATION...VALID THRU 02/06Z. WIDESPREAD RAIN AND SNOW WILL OCCUR INTO THURSDAY MORNING...THEN SCATTERED RAIN/SNOW SHOWERS WILL PREVAIL EAST OF KTUS THURSDAY AFTERNOON AND THURSDAY EVENING. EXPECT WIDESPREAD MVFR CONDITIONS INTO THURSDAY MORNING ALONG WITH OCCASIONAL IFR CONDITIONS. CLOUDS WILL DECREASE WEST OF KTUS THURSDAY AFTERNOON FOLLOWED BY GRADUALLY IMPROVING SKY CONDITIONS FURTHER EASTWARD TO INCLUDE KTUS THURSDAY EVENING. SURFACE WIND EAST OF KTUS THE REST OF TONIGHT WILL BE SLY TO WLY AT 12-20 KTS WITH GUSTS TO 30 KTS. THEREAFTER... SURFACE WIND WILL BE MAINLY LESS THAN 10 KTS MOST SECTIONS THURSDAY AND THURSDAY EVENING. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...EXPECT WIDESPREAD RAIN AND SNOW INTO THURSDAY AS A WINTER STORM SYSTEM MOVES ACROSS THE AREA. A FEW LINGERING SHOWERS WILL OCCUR EAST OF TUCSON THURSDAY NIGHT INTO FRIDAY. THEREAFTER... DRY CONDITIONS WILL OCCUR THIS WEEKEND AND INTO NEXT WEEK. && .PREV DISCUSSION...THE NEXT AREA OF CONCERN WILL BE SUB-FREEZING LOW TEMPS FRIDAY AND SATURDAY MORNINGS...WHEN LOW TEMPS ARE EXPECTED TO BE IN THE MID 20S TO NEAR 30 FOR MUCH OF THE TUCSON METRO AND INTO CENTRAL PIMA COUNTY AND SOUTHEAST PINAL COUNTY. AFTER INSPECTION OF 12Z MOS LOW TEMP NUMBERS FOR FRIDAY AND SATURDAY MORNINGS...DECIDED TO GO WITH A HARD FREEZE WATCH FOR SOUTHEAST PINAL COUNTY...CENTRAL AND EASTERN PORTIONS OF PIMA COUNTY FRIDAY MORNING...THEN JUST FOR EASTERN PORTIONS OF PIMA COUNTY AND EASTERN PINAL COUNTY FOR SATURDAY MORNING SINCE THE LOWS WILL BE SLIGHTLY WARMER SATURDAY MORNING COMPARED TO FRIDAY...AND AREAL COVERAGE OF TEMPS AT OR BELOW 27 DEGS F WILL BE SMALLER. AS THE LOW BEGINS TO EJECT TO THE EAST LATE THURSDAY INTO FRIDAY... LINGERING MOISTURE AND COLD AIR WILL JUSTIFY KEEPING A WINTER WEATHER ADVISORY FOR THE MOUNTAINS OF GRAHAM AND GREENLEE COUNTIES AND FOR THE SANTA CATALINA AND RINCON MOUNTAINS OF EASTERN PIMA COUNTY THROUGH LATE THURSDAY AFTERNOON. THE LOW WILL BE FAR ENOUGH TO OUR EAST BY LATE FRIDAY/EARLY SATURDAY TO RESULT IN A RETURN TO DRY CONDITIONS THROUGH THE REMAINDER OF THE FORECAST PERIOD WITH A WARMING TREND BEGINNING EARLY NEXT WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL 11 AM MST THURSDAY FOR AZZ510-511-514. WINTER STORM WARNING UNTIL 11 AM MST THURSDAY FOR AZZ506-509 ABOVE 4000 FEET. WINTER WEATHER ADVISORY UNTIL 11 AM MST THURSDAY FOR AZZ512-513. WINTER WEATHER ADVISORY FROM 11 AM TO 5 PM MST THURSDAY FOR AZZ510-511-514. HARD FREEZE WARNING FROM 3 AM TO 9 AM MST FRIDAY FOR AZZ502- 504>506. FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING FOR AZZ504-506. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON FRANCIS PREV DISCUSSION...MOLLERE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
501 AM EST THU JAN 1 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 429 PM EST WED DEC 31 2014 WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW FROM NW CANADA INTO THE GREAT LAKES BETWEEN A TROUGH OVER HUDSON BAY AND A RIDGE FROM THE ERN PACIFIC INTO BC. A SHORTWAVE TROUGH WAS MOVING THROUGH UPPER MI WITH ANOTHER WEAKER SHRTWV UPSTREAM OVER MANITOBA. ANOTHER CLIPPER SHRTWV WAS FARTHER UPSTREAM OVER NW SASK. AT THE SFC...STRONG WEST WINDS PREVAILED ACROSS THE REGION BETWEEN A 988 MB LOW NEAR HUDSON BAY AND 1036 MB ARCTIC HIGH PRES INTO THE SRN PLAINS. THE STRONGEST WINDS THIS MORNING INTO EARLY AFTERNOON ACROSS LAKE SUPERIOR OCCURRED AS THE STRONGER PRES FALLS SLID THROUGH NRN ONTARIO. WITH 850 MB TEMPS AROUND -19C AND CONVERGENT WRLY FLOW DEVELOPING LES HAS INCREASED ACROSS THE KEWEENAW AS WINDS VEERED FROM SW TO W. TONIGHT...EXPECT THE STRONGEST LOW LEVEL CONV SUPPORTING LES TO REMAIN OVER THE KEWEENAW. EVEN WITH A FAVORABLE POSITION OF THE DGZ IN THE CLOUD LAYER...THE STRONGER WINDS WILL CREATE ENOUGH COMPACTION/FRACTURING TO LIMIT SLR VALUES CLOSER TO 20/1. SO OVERALL ACCUMULATIONS TONIGHT IN THE 2 TO 5 INCH RANGE ARE EXPECTED. WINDS GUSTING INTO THE 30 TO 40 MPH RANGE WILL ALSO CONTINUE TO PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW IN OPEN AREAS WHERE OCNL WHITEOUT CONDITIONS ARE POSSIBLE. WINDS ARE EXPECTED TO DIMINISH OVERNIGHT REDUCING THE BLSN HAZARDS. THU...THE NRN SASK SHRTWV TROUGH WILL BRUSH THE AREA WITH ENOUGH 700-500 MB QVECTOR CONV AND 800-600 MB FGEN TO SUPPORT AN AREA OF LIGHT SNOW FROM NRN MN INTO NRN WI AND UPPER MI. WITH THE LACK OF SIGNFICANT MOISTURE INFLOW/AVAILABILITY...SNOW AMOUNTS OF A HALF INCH OR LESS ARE EXPECTED. HOWEVER...THE DEEPER MOISTURE WITH INCREASING INVERSION HEIGHTS INTO THE AREA WILL SUPPORT GREATER LES INTENSITY FOR THE W TO WNW FLOW LES SNOW BELTS. SINCE THE STRONGER LOW LEVEL CONV IS EXPECTED TO SHIFT SOUTHWARD OVERALL SNOW AMOUNTS SHOULD REMAIN IN THE 1 TO 3 INCH RANGE. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 501 AM EST THU JAN 1 2015 PERSISTENT RIDGING OVER THE EASTERN PACIFIC/NAMERICA WEST COAST REGION WILL MAINTAIN A BROAD UPPER TROUGH OVER MUCH OF CANADA AND THE GREAT LAKES REGION THROUGH THE FIRST WEEK OF JANUARY RESULTING IN BELOW NORMAL TEMPERATURES AND PERIODS OF LAKE EFFECT SNOW FOR UPPER MI. BEGINNING FRIDAY...MODEL CONSENSUS SUGGESTS WINDS WL BACK MORE WESTERLY AGAIN AS SFC RDG AXIS ADVANCES ACROSS AREA FROM THE NRN PLAINS. THE GENERALLY WEAK WRLY FLOW ALONG WITH ENHANCED LOW-LVL CONVERGENCE FROM LAND BREEZES WL HELP FOCUS GENERALLY LIGHT LAKE EFFECT SNOW ACROSS THE KEWEENAN PENINSULA AND THE FAR ERN SHORELINE OF THE CWA AS INVERSION BASES CRASH BLO 5KFT WITH DRY AIR NOTED BENEATH THE INVERSION. SINCE MUCH OF THE DGZ IN STILL WITHIN THE CLOUD LAYER...LES BANDS COULD YIELD 1-2 INCHES OF FLUFFY ACCUMULATION DURING THE DAY. WAA CLOUDS AHEAD OF SHORTWAVE MOVING IN FROM THE NRN PLAINS WILL LIMIT RADIATIONAL COOLING FRIDAY NIGHT BUT TEMPS SHOULD STILL APPROACH ZERO OR MAYBE EVEN DIP BLO ZERO AT A FEW OF THE TYPICAL COLDER LOCATIONS OVER THE WESTERN INTERIOR. THIS WEEKEND...FOCUS IS ON PHASING/INTERACTION OF SPLIT FLOW. TWO FEATURES WILL COME INTO PLAY...ONE WILL BE THE REMNANTS OF A CLOSED LOW NOW PRODUCING SNOW OVER THE SW CONUS...AND THE SECOND IS A NRN BRANCH SHORTWAVE NOW OVER THE ALEUTIAN ISLANDS WHICH IS FCST TO DIVE SE ACROSS THE NRN ROCKIES FRI NIGHT AND THEN THROUGH THE PLAINS STATES ON SAT. ASSOCIATED STRONG MID LEVEL WARM AIR ADVECTION AHEAD OF THIS SHORTWAVE AND ITS ASSOC SFC LOW WILL SPREAD SNOW EAST INTO MAINLY THE NORTHWEST HALF OF THE CWA ON SAT. WHILE THE MODELS STILL PEG THE HEAVIEST SNOW TO OCCUR OVER LAKE SUPERIOR...WILL CONTINUE TO SHOW SOME LIKELY POPS OVER AND AROUND THE KEWEENAW PENINSULA FOR SATURDAY. AS THIS SNOW IS OCCURRING...THE NORTHERN SHORTWAVE WILL CONTINUE TO DIVE SOUTHEAST AND BEGIN TO PHASE WITH THE REMNANTS OF THE SW CONUS UPPER LOW WHICH WILL LEAD TO BOTH FEATURES EJECTING NORTHEAST THROUGH THE LOWER GREAT LAKES REGION SATURDAY NIGHT INTO SUNDAY. THE 00Z ECMWF...GFS AND NAM ALL TRENDING DEEPER AND FARTHER WEST WITH RESULTING SFC LOW WHICH BLEND OF THESE MODELS SHOW A TRACK THROUGH SRN LWR MI TO NEAR GEORGIAN BAY BY 12Z SUNDAY. THE GEM-NH MEANWHILE AFTER SHOWING A SIMILAR TRACK TO THE 00Z ECMWF/GFS BLEND HAS NOW TRENDED FARTHER EAST THROUGH SE LOWER MI INTO ERN ONTARIO. IF THE LATEST GFS/ECMWF SOLNS HOLD TRUE THIS WOULD MEAN A GREATER POTENTIAL FOR SYNOPTIC PCPN TO SPREAD INTO UPPER MI...ESPECIALLY THE EAST HALF...ALONG WITH A GREATER POTENTIAL FOR NORTH FLOW LAKE ENHANCED SNOW ON THE BACKSIDE OF THE SYSTEM. WILL LIKELY NEED TO TREND POPS UPWARD ACROSS THE CWA AND ESPECIALLY ALONG LAKE SUPERIOR ZONES WITH A GREATER POTENTIAL FOR LAKE ENHANCED SNOW SAT NIGHT INTO SUNDAY. WINDS WILL ALSO RAMP UP WITH TIGHTER GRADIENT ON BACKSIDE OF SYSTEM WHICH WILL ALSO RESULT IN MORE BLOWING SNOW. WILL HIGHLIGHT POTENTIAL FOR MODERATE SNOW AND BLOWING SNOW IN HWO...ESPECIALLY ALONG LAKE SUPERIOR AND THE EAST HALF OF THE CWA FOR SAT NIGHT INTO SUNDAY EVENING. LATE SUNDAY NIGHT INTO MONDAY NIGHT...WEAKENING PRES GRADIENT WILL ALLOW WINDS TO DIMINISH ESPECIALLY OVER THE INTERIOR. WINDS WILL ALSO BE BACKING MORE WESTERLY ESPECIALLY BY MONDAY IN ADVANCE OF STRONG SFC HIGH PRES RDG BUILDING IN FROM THE NRN PLAINS...SO EXPECT LES TO EVENTUALLY BECOME MORE CONFINED TO KEWEENAW AND FAR ERN SHORELINE AREAS OF THE CWA MONDAY AFTERNOON INTO MON NIGHT. WITH HEART OF COLDEST AIR (850 MB TEMPS OF -26 TO -28C) COMING ACROSS THE UPPER LAKES...EXPECT VERY COLD TEMPS SUN NIGHT AND MONDAY. EXPECT MUCH OF THE INTERIOR CWA TO FALL BLO ZERO AND WOULD NOT BE SURPRISED TO SEE SOME WESTERN INTERIOR LOCATIONS FALL WELL INTO THE TEENS BLO ZERO... ESPECIALLY ALONG THE WI BORDER. HIGHS MONDAY WILL REMAIN VERY COLD WITH READINGS RANGING FROM THE SINGLE DIGITS BLO ZERO WESTERN INTERIOR TO THE SINGLE DIGITS ABV ZERO EAST AND ALONG THE GREAT LAKES. TUESDAY INTO WEDNESDAY...MODELS IN REASONABLY GOOD AGREEMENT SHOWING ANOTHER CLIPPER SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES ON TUESDAY WITH ANOTHER REINFORCING SHOT OF ARCTIC AIR (8H TEMPS FALL AGAIN TO -28C TO -30C) AS WINDS VEER TO THE NW. THIS WILL BRING LES FARTHER INLAND AGAIN AFFECTING THE NRN TIER AND ERN HALF COUNTIES FROM LATE TUE THROUGH WED. LOOK LIKE ONLY THE FAR SOUTH CENTRAL WOULD ESCAPE THE LES. WITH SUCH A COLD ARCTIC AIRMASS FCST THE DGZ WILL GET SQUASHED NEAR THE LAKE SFC WHICH WILL LIKELY RESULT IN SMALLER FLAKE SIZE. THIS WILL LIMIT LES ACCUMULATION BUT AT SAME TIME WILL BE MORE EFFECTIVE FOR REDUCING VSBY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1209 AM EST THU JAN 1 2015 WINDS HAVE BECOME MORE WESTERLY OVER THE WESTERN U.P. WITH THE PASSAGE OF A WEAK SHORTWAVE. WESTERLY FLOW HAS RESULTED IN ENHANCED LES AT KCMX AT TIMES...WITH VSBYS OCCASIONALLY FALLING TO LIFR DUE TO SNOW AND BLOWING SNOW WHILE CIGS LOWER TO IFR. AS WINDS VEER TO NW DURING THE LATE MORNING HOURS...EXPECT KCMX CONDITIONS TO IMPROVE WITH MVFR PREVAILING BY MIDDAY. KIWD TO SEE LES AND BLSN IN NW FLOW WITH MAINLY MVFR CONDITIONS THERE...WITH BRIEF PERIODS OF IFR DUE TO HEAVIER LES. KSAW TO SEE MVFR CONDITIONS AS NW DOWNSLOPE THERE NOT FAVORABLE FOR LOWER CIGS/VSBYS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 412 AM EST THU JAN 1 2015 A LOW OVER S HUDSON BAY WILL SHIFT INTO N QUEBEC FRIDAY MORNING. THE TROUGH EXTENDING FROM THIS LOW ACROSS LAKE SUPERIOR WILL SLOWLY WEAKEN. AS A RESULT...EXPECT THE GALES OF 35-40KTS TO SLOWLY DIMINISH TOO. WHILE HEAVY FREEZING SPRAY HAS DIMINISHED THIS MORNING...IT WILL PICK UP AGAIN OVER N LAKE SUPERIOR THIS AFTERNOON-EVENING. HIGH PRESSURE SINKING ACROSS MINNESOTA THIS EVENING WILL STRETCH FROM THE GREAT LAKES THROUGH THE OHIO VALLEY ON FRIDAY...AND EXIT TO SOUTHERN QUEBEC AND THE NEW ENGLAND STATES FRIDAY NIGHT. EXPECT A LOW ACROSS THE DAKOTAS FRIDAY NIGHT TO CONSOLIDATE WITH AN ADDITIONAL LOW ACROSS THE MISSISSIPPI VALLEY. THE NEW LOW WILL MOVE NE AND DEEPEN ACROSS LOWER MICHIGAN AND LAKE HURON SATURDAY NIGHT...AND EXIT S QUEBEC ON SUNDAY. THIS WILL BRING A TROUGH SATURDAY NIGHT INTO SUNDAY FOR LAKE SUPERIOR. N-NW GALES OF 35 TO NEAR 40KTS WILL AGAIN BE POSSIBLE SUNDAY INTO SUNDAY EVENING. BY MONDAY...A RIDGE WILL SETTLE ACROSS THE N PLAINS AND UPPER MISSISSIPPI VALLEY. HEAVY FREEZING SPRAY WILL ALSO RETURN AS A COLD RIDGE WILL SETTLE ACROSS THE N PLAINS AND UPPER MISSISSIPPI VALLEY MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ001-003. LAKE SUPERIOR... GALE WARNING UNTIL 10 AM EST THIS MORNING FOR LSZ266-267. GALE WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR LSZ162- 241>251-263>265. HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 3 AM EST FRIDAY FOR LSZ263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...VOSS AVIATION...RJT MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
414 AM EST THU JAN 1 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 429 PM EST WED DEC 31 2014 WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW FROM NW CANADA INTO THE GREAT LAKES BETWEEN A TROUGH OVER HUDSON BAY AND A RIDGE FROM THE ERN PACIFIC INTO BC. A SHORTWAVE TROUGH WAS MOVING THROUGH UPPER MI WITH ANOTHER WEAKER SHRTWV UPSTREAM OVER MANITOBA. ANOTHER CLIPPER SHRTWV WAS FARTHER UPSTREAM OVER NW SASK. AT THE SFC...STRONG WEST WINDS PREVAILED ACROSS THE REGION BETWEEN A 988 MB LOW NEAR HUDSON BAY AND 1036 MB ARCTIC HIGH PRES INTO THE SRN PLAINS. THE STRONGEST WINDS THIS MORNING INTO EARLY AFTERNOON ACROSS LAKE SUPERIOR OCCURRED AS THE STRONGER PRES FALLS SLID THROUGH NRN ONTARIO. WITH 850 MB TEMPS AROUND -19C AND CONVERGENT WRLY FLOW DEVELOPING LES HAS INCREASED ACROSS THE KEWEENAW AS WINDS VEERED FROM SW TO W. TONIGHT...EXPECT THE STRONGEST LOW LEVEL CONV SUPPORTING LES TO REMAIN OVER THE KEWEENAW. EVEN WITH A FAVORABLE POSITION OF THE DGZ IN THE CLOUD LAYER...THE STRONGER WINDS WILL CREATE ENOUGH COMPACTION/FRACTURING TO LIMIT SLR VALUES CLOSER TO 20/1. SO OVERALL ACCUMULATIONS TONIGHT IN THE 2 TO 5 INCH RANGE ARE EXPECTED. WINDS GUSTING INTO THE 30 TO 40 MPH RANGE WILL ALSO CONTINUE TO PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW IN OPEN AREAS WHERE OCNL WHITEOUT CONDITIONS ARE POSSIBLE. WINDS ARE EXPECTED TO DIMINISH OVERNIGHT REDUCING THE BLSN HAZARDS. THU...THE NRN SASK SHRTWV TROUGH WILL BRUSH THE AREA WITH ENOUGH 700-500 MB QVECTOR CONV AND 800-600 MB FGEN TO SUPPORT AN AREA OF LIGHT SNOW FROM NRN MN INTO NRN WI AND UPPER MI. WITH THE LACK OF SIGNFICANT MOISTURE INFLOW/AVAILABILITY...SNOW AMOUNTS OF A HALF INCH OR LESS ARE EXPECTED. HOWEVER...THE DEEPER MOISTURE WITH INCREASING INVERSION HEIGHTS INTO THE AREA WILL SUPPORT GREATER LES INTENSITY FOR THE W TO WNW FLOW LES SNOW BELTS. SINCE THE STRONGER LOW LEVEL CONV IS EXPECTED TO SHIFT SOUTHWARD OVERALL SNOW AMOUNTS SHOULD REMAIN IN THE 1 TO 3 INCH RANGE. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 316 PM EST WED DEC 31 2014 AN UPPER TROUGH OVER EASTERN CANADA LEAD TO COLD AIR AND LAKE EFFECT SNOW OVER THE NORTHWEST WIND SNOW BELTS TO START THE PERIOD. THIS LIGHT TO OCCASIONALLY MODERATE LAKE EFFECT SNOW WILL CONTINUE IN THOSE NORTHWEST WIND BELTS ON THURSDAY NIGHT...BUT AS THE LOW LEVEL WINDS BACK LATE THURSDAY NIGHT INTO FRIDAY MORNING...WILL FOCUS THE POPS/SNOW TO THE WEST-NORTHWEST AREAS ON FRIDAY (AND WESTERLY AREAS LATE FRIDAY AFTERNOON). WHILE LAKE INDUCED EQUILIBRIUM LEVELS WILL BE AROUND 8KFT...THERE ARE SOME CONCERNS IN THE AMOUNT OF MOISTURE AVAILABLE AS SUBSIDENCE AND DRIER AIR ARRIVE THURSDAY NIGHT FROM A HIGH MOVING SOUTHEAST INTO MINNESOTA. THUS...WILL STICK WITH A DUSTING TO 3-4IN EVERY 12HRS THROUGH FRIDAY...WITH THE HIGHEST AMOUNTS OVER THE EAST WITH THE LONGER FETCH AND SOME INDICATIONS OF A LINGERING TROUGH AIDING CONVERGENCE TOWARDS WHITEFISH POINT. THE HIGH WILL SHIFT SOUTHEAST OF THE AREA ON FRIDAY EVENING...BACKING WINDS TO THE SOUTHWEST AND ONLY LEAVING LAKE EFFECT SNOW OVER THE KEWEENAW FOR FRIDAY NIGHT. THE FOCUS THEN TURNS TO THE INTERACTION AND PHASING OF THE SPLIT FLOW FOR THE START OF THE WEEKEND. MODELS SEEM TO COMING INTO BETTER AGREEMENT ON THE OVERALL IDEA FOR THE WEEKEND...ALTHOUGH THERE ARE STILL SMALLER DIFFERENCES THAT COULD HAVE AN IMPACT ON THE AMOUNT OF SNOW SEEN OVER PARTS OF THE U.P. THERE ARE TWO FEATURES AT PLAY FOR THIS WEEKEND...THE FIRST IS THE REMNANTS OF THE UPPER LOW PRODUCING SNOW OVER THE SOUTHWEST CONUS TODAY AND THE SECOND FEATURE IS A SHORTWAVE CURRENTLY OVER THE ALEUTIANS ISLANDS AND DROPPING SOUTHEAST INTO THE NORTHERN ROCKIES ON FRIDAY NIGHT. THIS WILL LEAD TO A LOW DEVELOPING IN THE LEE OF THE NORTHERN ROCKIES AND THEN MOVING EAST INTO THE DAKOTAS AND WESTERN MINNESOTA BY SATURDAY MORNING. EXPECT SNOW TO SPREAD EAST AHEAD OF THIS LOW AND INTO THE NORTHWEST HALF OF THE CWA...ASSOCIATED WITH STRONG MID LEVEL WARM AIR ADVECTION. WHILE THE HEAVIEST SNOW APPEARS TO OCCUR OVER LAKE SUPERIOR...WILL SHOW SOME LIKELY POPS OVER AND AROUND THE KEWEENAW PENINSULA FOR SATURDAY. AS THAT IS OCCURRING...THE NORTHERN SHORTWAVE WILL CONTINUE TO DIVE SOUTHEAST AND PHASE WITH THE SOUTHERN UPPER LOW AND LEAD TO BOTH EJECTING NORTHEAST THROUGH THE LOWER GREAT LAKES REGION SATURDAY NIGHT INTO SUNDAY. AS EXPECTED IN THESE PHASING EVENTS...EACH MODEL RUN GIVES A SLIGHTLY DIFFERENT IDEA ON THE EVOLUTION OF THE PHASED FEATURES AND IN TURN THE SURFACE FEATURES. OVERALL...THE GENERAL IDEA IS FOR A STRENGTHENING LOW TO LIFT NORTHEAST THROUGH SOUTHEAST LOWER MICHIGAN ON SATURDAY NIGHT AND THEN INTO QUEBEC ON SUNDAY. WITH THAT TRACK...WOULD EXPECT MUCH OF THE SYNOPTIC FORCING/PRECIPITATION ASSOCIATED WITH THOSE FEATURES TO MISS THE U.P....BUT WOULD STILL EXPECT AT LEAST SOME LAKE ENHANCEMENT AS THE WINDS TURN TO THE NORTHWEST BEHIND THE ELONGATED SURFACE TROUGH STRETCHING NORTH OVER EASTERN LAKE SUPERIOR LATE SATURDAY NIGHT. INITIALLY...WOULDN/T EXPECT THE LAKE ENHANCEMENT TO AMOUNT TO TOO HIGH OF SNOWFALL AMOUNTS ON SATURDAY NIGHT...BUT AS MUCH COLDER AIR MOVES INTO THE AREA (850MB TEMPS FALLING TO -25C BY 00Z MONDAY) AND THE DEEPER MOISTURE IS STILL PRESENT FROM THE DEPARTING SYSTEM...WOULD EXPECT THE LAKE ENHANCEMENT/EFFECT SNOW TO TAKE OFF ON SUNDAY IN THE NORTHWEST WIND SNOW BELTS. WILL TREND POPS UP TO DEFINITE VALUES DURING THIS PERIOD AND CONTINUE TO MENTION MODERATE/HEAVY SNOW WORDING IN THE HWO. BEHIND THE LOW...EXPECT THE FIRST PART OF THE WORK WEEK TO BE VERY COLD WITH CONTINUED LAKE EFFECT SNOW. THE CANADIAN UPPER TROUGH WILL SAG SOUTH INTO THE GREAT LAKES REGION AND KEEP THE COLD AIR IN PLACE (850MB TEMPS IN THE LOW 20C BELOW ZERO)...WITH ANOTHER SHORTWAVE MOVING THROUGH ON MONDAY NIGHT POTENTIALLY PULLING 850MB TEMPERATURES CLOSE TO -30C FOR TUESDAY. THAT WILL LEAD TO VERY COLD HIGH TEMPERATURES FOR MONDAY/TUESDAY...WITH SOME LOCATIONS OVER THE INTERIOR WEST EVEN STRUGGLING TO RISE ABOVE 0. IN FACT...LOOKING AT THE 00Z ECMWF ENSEMBLE MEMBERS AT KSAW AND OTHER SITES IN THE WESTERN/CENTRAL U.P....THERE MAY END UP BEING A 24-36 HOUR PERIOD OF SUB ZERO TEMPERATURES LATE SUNDAY NIGHT THROUGH AT LEAST TUESDAY MORNING. THE COMBINATION OF THE COLD TEMPERATURES AT NIGHT (SINGLE DIGITS AND TEENS BELOW ZERO) AND WINDS IN THE 5-10MPH RANGE WILL LEAD TO LOW WIND CHILL VALUES MONDAY/TUESDAY MORNINGS AND POTENTIALLY EVENING WEDNESDAY MORNING. AS LONG AS THE WIND SPEEDS STAY UP...WOULD EXPECT THE NEED FOR WIND CHILL ADVISORIES AT A MINIMUM AND WILL CONTINUE TO ADDRESS IN THE HWO. AS FOR LAKE EFFECT DURING THE FIRST PART OF NEXT WEEK...EXPECT WINDS TO BACK TO THE WEST ON MONDAY AND WILL FOCUS THE LAKE EFFECT POPS IN THOSE AREAS. WITH THE AMOUNT OF COLD AIR IN PLACE...VERY LITTLE OF THE CLOUD LAYER WILL BE IN THE DGZ AND MOST WILL BE ABOVE IT...WHICH LEADS TO MORE COLUMN/PLATE SNOWFLAKES AND WOULD EXPECT ACCUMULATIONS TO BE LIMITED. WINDS WILL SHIFT MORE TO THE NORTHWEST ON TUESDAY BEHIND THAT NEXT SHORTWAVE AND WILL TREND POPS TO THAT FAVORED WIND DIRECTION. WITH THE AMOUNT OF COLD AIR...THERE SHOULDN/T BE MUCH OF AN ISSUE FOR AT LEAST SOME LAKE EFFECT...SO DID TREND POPS UP TO LIKELY-DEFINITE VALUES EVEN THOUGH AMOUNTS SHOULD BE LIMITED. AS THE UPPER TROUGH SHIFTS EAST ON WEDNESDAY AND THROUGH THE END OF THE WORK WEEK...THE UPPER GREAT LAKES REGION SHOULD SEE A MODERATION IN THEIR TEMPERATURES TOWARDS MORE NORMAL VALUES TOWARDS THE END OF NEXT WEEK. LOOKING AT THE 00Z ECMWF ENSEMBLE MEAN FOR DAYS 9-15...IT SHOWS MORE OF A ZONAL FLOW ACROSS THE CONUS...WHICH WOULD TRANSLATE TO MORE NORMAL OR EVEN SLIGHTLY ABOVE NORMAL TEMPERATURES HEADING INTO THE MIDDLE OF JANUARY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1209 AM EST THU JAN 1 2015 WINDS HAVE BECOME MORE WESTERLY OVER THE WESTERN U.P. WITH THE PASSAGE OF A WEAK SHORTWAVE. WESTERLY FLOW HAS RESULTED IN ENHANCED LES AT KCMX AT TIMES...WITH VSBYS OCCASIONALLY FALLING TO LIFR DUE TO SNOW AND BLOWING SNOW WHILE CIGS LOWER TO IFR. AS WINDS VEER TO NW DURING THE LATE MORNING HOURS...EXPECT KCMX CONDITIONS TO IMPROVE WITH MVFR PREVAILING BY MIDDAY. KIWD TO SEE LES AND BLSN IN NW FLOW WITH MAINLY MVFR CONDITIONS THERE...WITH BRIEF PERIODS OF IFR DUE TO HEAVIER LES. KSAW TO SEE MVFR CONDITIONS AS NW DOWNSLOPE THERE NOT FAVORABLE FOR LOWER CIGS/VSBYS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 412 AM EST THU JAN 1 2015 A LOW OVER S HUDSON BAY WILL SHIFT INTO N QUEBEC FRIDAY MORNING. THE TROUGH EXTENDING FROM THIS LOW ACROSS LAKE SUPERIOR WILL SLOWLY WEAKEN. AS A RESULT...EXPECT THE GALES OF 35-40KTS TO SLOWLY DIMINISH TOO. WHILE HEAVY FREEZING SPRAY HAS DIMINISHED THIS MORNING...IT WILL PICK UP AGAIN OVER N LAKE SUPERIOR THIS AFTERNOON-EVENING. HIGH PRESSURE SINKING ACROSS MINNESOTA THIS EVENING WILL STRETCH FROM THE GREAT LAKES THROUGH THE OHIO VALLEY ON FRIDAY...AND EXIT TO SOUTHERN QUEBEC AND THE NEW ENGLAND STATES FRIDAY NIGHT. EXPECT A LOW ACROSS THE DAKOTAS FRIDAY NIGHT TO CONSOLIDATE WITH AN ADDITIONAL LOW ACROSS THE MISSISSIPPI VALLEY. THE NEW LOW WILL MOVE NE AND DEEPEN ACROSS LOWER MICHIGAN AND LAKE HURON SATURDAY NIGHT...AND EXIT S QUEBEC ON SUNDAY. THIS WILL BRING A TROUGH SATURDAY NIGHT INTO SUNDAY FOR LAKE SUPERIOR. N-NW GALES OF 35 TO NEAR 40KTS WILL AGAIN BE POSSIBLE SUNDAY INTO SUNDAY EVENING. BY MONDAY...A RIDGE WILL SETTLE ACROSS THE N PLAINS AND UPPER MISSISSIPPI VALLEY. HEAVY FREEZING SPRAY WILL ALSO RETURN AS A COLD RIDGE WILL SETTLE ACROSS THE N PLAINS AND UPPER MISSISSIPPI VALLEY MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ001-003. LAKE SUPERIOR... GALE WARNING UNTIL 10 AM EST THIS MORNING FOR LSZ266-267. GALE WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR LSZ162- 241>251-263>265. HEAVY FREEZING SPRAY WARNING FROM 1 PM THIS AFTERNOON TO 3 AM EST FRIDAY FOR LSZ263-264. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...RJT MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1210 AM EST THU JAN 1 2015 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 429 PM EST WED DEC 31 2014 WV IMAGERY AND RUC ANALYSIS INDICATED NW MID/UPPER LEVEL FLOW FROM NW CANADA INTO THE GREAT LAKES BETWEEN A TROUGH OVER HUDSON BAY AND A RIDGE FROM THE ERN PACIFIC INTO BC. A SHORTWAVE TROUGH WAS MOVING THROUGH UPPER MI WITH ANOTHER WEAKER SHRTWV UPSTREAM OVER MANITOBA. ANOTHER CLIPPER SHRTWV WAS FARTHER UPSTREAM OVER NW SASK. AT THE SFC...STRONG WEST WINDS PREVAILED ACROSS THE REGION BETWEEN A 988 MB LOW NEAR HUDSON BAY AND 1036 MB ARCTIC HIGH PRES INTO THE SRN PLAINS. THE STRONGEST WINDS THIS MORNING INTO EARLY AFTERNOON ACROSS LAKE SUPERIOR OCCURRED AS THE STRONGER PRES FALLS SLID THROUGH NRN ONTARIO. WITH 850 MB TEMPS AROUND -19C AND CONVERGENT WRLY FLOW DEVELOPING LES HAS INCREASED ACROSS THE KEWEENAW AS WINDS VEERED FROM SW TO W. TONIGHT...EXPECT THE STRONGEST LOW LEVEL CONV SUPPORTING LES TO REMAIN OVER THE KEWEENAW. EVEN WITH A FAVORABLE POSITION OF THE DGZ IN THE CLOUD LAYER...THE STRONGER WINDS WILL CREATE ENOUGH COMPACTION/FRACTURING TO LIMIT SLR VALUES CLOSER TO 20/1. SO OVERALL ACCUMULATIONS TONIGHT IN THE 2 TO 5 INCH RANGE ARE EXPECTED. WINDS GUSTING INTO THE 30 TO 40 MPH RANGE WILL ALSO CONTINUE TO PRODUCE CONSIDERABLE BLOWING AND DRIFTING SNOW IN OPEN AREAS WHERE OCNL WHITEOUT CONDITIONS ARE POSSIBLE. WINDS ARE EXPECTED TO DIMINISH OVERNIGHT REDUCING THE BLSN HAZARDS. THU...THE NRN SASK SHRTWV TROUGH WILL BRUSH THE AREA WITH ENOUGH 700-500 MB QVECTOR CONV AND 800-600 MB FGEN TO SUPPORT AN AREA OF LIGHT SNOW FROM NRN MN INTO NRN WI AND UPPER MI. WITH THE LACK OF SIGNFICANT MOISTURE INFLOW/AVAILABILITY...SNOW AMOUNTS OF A HALF INCH OR LESS ARE EXPECTED. HOWEVER...THE DEEPER MOISTURE WITH INCREASING INVERSION HEIGHTS INTO THE AREA WILL SUPPORT GREATER LES INTENSITY FOR THE W TO WNW FLOW LES SNOW BELTS. SINCE THE STRONGER LOW LEVEL CONV IS EXPECTED TO SHIFT SOUTHWARD OVERALL SNOW AMOUNTS SHOULD REMAIN IN THE 1 TO 3 INCH RANGE. .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 316 PM EST WED DEC 31 2014 AN UPPER TROUGH OVER EASTERN CANADA LEAD TO COLD AIR AND LAKE EFFECT SNOW OVER THE NORTHWEST WIND SNOW BELTS TO START THE PERIOD. THIS LIGHT TO OCCASIONALLY MODERATE LAKE EFFECT SNOW WILL CONTINUE IN THOSE NORTHWEST WIND BELTS ON THURSDAY NIGHT...BUT AS THE LOW LEVEL WINDS BACK LATE THURSDAY NIGHT INTO FRIDAY MORNING...WILL FOCUS THE POPS/SNOW TO THE WEST-NORTHWEST AREAS ON FRIDAY (AND WESTERLY AREAS LATE FRIDAY AFTERNOON). WHILE LAKE INDUCED EQUILIBRIUM LEVELS WILL BE AROUND 8KFT...THERE ARE SOME CONCERNS IN THE AMOUNT OF MOISTURE AVAILABLE AS SUBSIDENCE AND DRIER AIR ARRIVE THURSDAY NIGHT FROM A HIGH MOVING SOUTHEAST INTO MINNESOTA. THUS...WILL STICK WITH A DUSTING TO 3-4IN EVERY 12HRS THROUGH FRIDAY...WITH THE HIGHEST AMOUNTS OVER THE EAST WITH THE LONGER FETCH AND SOME INDICATIONS OF A LINGERING TROUGH AIDING CONVERGENCE TOWARDS WHITEFISH POINT. THE HIGH WILL SHIFT SOUTHEAST OF THE AREA ON FRIDAY EVENING...BACKING WINDS TO THE SOUTHWEST AND ONLY LEAVING LAKE EFFECT SNOW OVER THE KEWEENAW FOR FRIDAY NIGHT. THE FOCUS THEN TURNS TO THE INTERACTION AND PHASING OF THE SPLIT FLOW FOR THE START OF THE WEEKEND. MODELS SEEM TO COMING INTO BETTER AGREEMENT ON THE OVERALL IDEA FOR THE WEEKEND...ALTHOUGH THERE ARE STILL SMALLER DIFFERENCES THAT COULD HAVE AN IMPACT ON THE AMOUNT OF SNOW SEEN OVER PARTS OF THE U.P. THERE ARE TWO FEATURES AT PLAY FOR THIS WEEKEND...THE FIRST IS THE REMNANTS OF THE UPPER LOW PRODUCING SNOW OVER THE SOUTHWEST CONUS TODAY AND THE SECOND FEATURE IS A SHORTWAVE CURRENTLY OVER THE ALEUTIANS ISLANDS AND DROPPING SOUTHEAST INTO THE NORTHERN ROCKIES ON FRIDAY NIGHT. THIS WILL LEAD TO A LOW DEVELOPING IN THE LEE OF THE NORTHERN ROCKIES AND THEN MOVING EAST INTO THE DAKOTAS AND WESTERN MINNESOTA BY SATURDAY MORNING. EXPECT SNOW TO SPREAD EAST AHEAD OF THIS LOW AND INTO THE NORTHWEST HALF OF THE CWA...ASSOCIATED WITH STRONG MID LEVEL WARM AIR ADVECTION. WHILE THE HEAVIEST SNOW APPEARS TO OCCUR OVER LAKE SUPERIOR...WILL SHOW SOME LIKELY POPS OVER AND AROUND THE KEWEENAW PENINSULA FOR SATURDAY. AS THAT IS OCCURRING...THE NORTHERN SHORTWAVE WILL CONTINUE TO DIVE SOUTHEAST AND PHASE WITH THE SOUTHERN UPPER LOW AND LEAD TO BOTH EJECTING NORTHEAST THROUGH THE LOWER GREAT LAKES REGION SATURDAY NIGHT INTO SUNDAY. AS EXPECTED IN THESE PHASING EVENTS...EACH MODEL RUN GIVES A SLIGHTLY DIFFERENT IDEA ON THE EVOLUTION OF THE PHASED FEATURES AND IN TURN THE SURFACE FEATURES. OVERALL...THE GENERAL IDEA IS FOR A STRENGTHENING LOW TO LIFT NORTHEAST THROUGH SOUTHEAST LOWER MICHIGAN ON SATURDAY NIGHT AND THEN INTO QUEBEC ON SUNDAY. WITH THAT TRACK...WOULD EXPECT MUCH OF THE SYNOPTIC FORCING/PRECIPITATION ASSOCIATED WITH THOSE FEATURES TO MISS THE U.P....BUT WOULD STILL EXPECT AT LEAST SOME LAKE ENHANCEMENT AS THE WINDS TURN TO THE NORTHWEST BEHIND THE ELONGATED SURFACE TROUGH STRETCHING NORTH OVER EASTERN LAKE SUPERIOR LATE SATURDAY NIGHT. INITIALLY...WOULDN/T EXPECT THE LAKE ENHANCEMENT TO AMOUNT TO TOO HIGH OF SNOWFALL AMOUNTS ON SATURDAY NIGHT...BUT AS MUCH COLDER AIR MOVES INTO THE AREA (850MB TEMPS FALLING TO -25C BY 00Z MONDAY) AND THE DEEPER MOISTURE IS STILL PRESENT FROM THE DEPARTING SYSTEM...WOULD EXPECT THE LAKE ENHANCEMENT/EFFECT SNOW TO TAKE OFF ON SUNDAY IN THE NORTHWEST WIND SNOW BELTS. WILL TREND POPS UP TO DEFINITE VALUES DURING THIS PERIOD AND CONTINUE TO MENTION MODERATE/HEAVY SNOW WORDING IN THE HWO. BEHIND THE LOW...EXPECT THE FIRST PART OF THE WORK WEEK TO BE VERY COLD WITH CONTINUED LAKE EFFECT SNOW. THE CANADIAN UPPER TROUGH WILL SAG SOUTH INTO THE GREAT LAKES REGION AND KEEP THE COLD AIR IN PLACE (850MB TEMPS IN THE LOW 20C BELOW ZERO)...WITH ANOTHER SHORTWAVE MOVING THROUGH ON MONDAY NIGHT POTENTIALLY PULLING 850MB TEMPERATURES CLOSE TO -30C FOR TUESDAY. THAT WILL LEAD TO VERY COLD HIGH TEMPERATURES FOR MONDAY/TUESDAY...WITH SOME LOCATIONS OVER THE INTERIOR WEST EVEN STRUGGLING TO RISE ABOVE 0. IN FACT...LOOKING AT THE 00Z ECMWF ENSEMBLE MEMBERS AT KSAW AND OTHER SITES IN THE WESTERN/CENTRAL U.P....THERE MAY END UP BEING A 24-36 HOUR PERIOD OF SUB ZERO TEMPERATURES LATE SUNDAY NIGHT THROUGH AT LEAST TUESDAY MORNING. THE COMBINATION OF THE COLD TEMPERATURES AT NIGHT (SINGLE DIGITS AND TEENS BELOW ZERO) AND WINDS IN THE 5-10MPH RANGE WILL LEAD TO LOW WIND CHILL VALUES MONDAY/TUESDAY MORNINGS AND POTENTIALLY EVENING WEDNESDAY MORNING. AS LONG AS THE WIND SPEEDS STAY UP...WOULD EXPECT THE NEED FOR WIND CHILL ADVISORIES AT A MINIMUM AND WILL CONTINUE TO ADDRESS IN THE HWO. AS FOR LAKE EFFECT DURING THE FIRST PART OF NEXT WEEK...EXPECT WINDS TO BACK TO THE WEST ON MONDAY AND WILL FOCUS THE LAKE EFFECT POPS IN THOSE AREAS. WITH THE AMOUNT OF COLD AIR IN PLACE...VERY LITTLE OF THE CLOUD LAYER WILL BE IN THE DGZ AND MOST WILL BE ABOVE IT...WHICH LEADS TO MORE COLUMN/PLATE SNOWFLAKES AND WOULD EXPECT ACCUMULATIONS TO BE LIMITED. WINDS WILL SHIFT MORE TO THE NORTHWEST ON TUESDAY BEHIND THAT NEXT SHORTWAVE AND WILL TREND POPS TO THAT FAVORED WIND DIRECTION. WITH THE AMOUNT OF COLD AIR...THERE SHOULDN/T BE MUCH OF AN ISSUE FOR AT LEAST SOME LAKE EFFECT...SO DID TREND POPS UP TO LIKELY-DEFINITE VALUES EVEN THOUGH AMOUNTS SHOULD BE LIMITED. AS THE UPPER TROUGH SHIFTS EAST ON WEDNESDAY AND THROUGH THE END OF THE WORK WEEK...THE UPPER GREAT LAKES REGION SHOULD SEE A MODERATION IN THEIR TEMPERATURES TOWARDS MORE NORMAL VALUES TOWARDS THE END OF NEXT WEEK. LOOKING AT THE 00Z ECMWF ENSEMBLE MEAN FOR DAYS 9-15...IT SHOWS MORE OF A ZONAL FLOW ACROSS THE CONUS...WHICH WOULD TRANSLATE TO MORE NORMAL OR EVEN SLIGHTLY ABOVE NORMAL TEMPERATURES HEADING INTO THE MIDDLE OF JANUARY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1209 AM EST THU JAN 1 2015 WINDS HAVE BECOME MORE WESTERLY OVER THE WESTERN U.P. WITH THE PASSAGE OF A WEAK SHORTWAVE. WESTERLY FLOW HAS RESULTED IN ENHANCED LES AT KCMX AT TIMES...WITH VSBYS OCCASIONALLY FALLING TO LIFR DUE TO SNOW AND BLOWING SNOW WHILE CIGS LOWER TO IFR. AS WINDS VEER TO NW DURING THE LATE MORNING HOURS...EXPECT KCMX CONDITIONS TO IMPROVE WITH MVFR PREVAILING BY MIDDAY. KIWD TO SEE LES AND BLSN IN NW FLOW WITH MAINLY MVFR CONDITIONS THERE...WITH BRIEF PERIODS OF IFR DUE TO HEAVIER LES. KSAW TO SEE MVFR CONDITIONS AS NW DOWNSLOPE THERE NOT FAVORABLE FOR LOWER CIGS/VSBYS. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 429 PM EST WED DEC 31 2014 LAKE SUPERIOR WILL BE STUCK BETWEEN VERY STRONG HIGH PRESSURE ACROSS THE S PLAINS AND A DEEP HUDSON BAY LOW TODAY. GALES OF 35-45KTS WILL CONTINUE BEFORE SLOWLY DIMINISHING TO 35KTS LATE TONIGHT INTO THURSDAY MORNING OUT OF THE W-NW. GIVEN PLENTY OF COLD AIR...AND STRONG WINDS...HEAVY FREEZING SPRAY WILL ALSO BE A CONCERN INTO THURSDAY. LOOK FOR THE TROUGH OVER LAKE SUPERIOR TO DEEPEN TONIGHT THROUGH THURSDAY. THE HUDSON BAY LOW WILL SHIFT AND WEAKEN ACROSS N QUEBEC THURSDAY NIGHT...ALLOWING THE TROUGH ACROSS LAKE SUPERIOR TO WEAKEN AS WELL. HIGH PRESSURE SINKING ACROSS MANITOBA AND MINNESOTA THURSDAY NIGHT WILL BUILD RIDGE ACROSS LAKE SUPERIOR ON FRIDAY AS IT PROGRESSES ACROSS THE REMAINDER OF THE GREAT LAKES. A WEAK TROUGH WILL LIKELY LINGER ACROSS MAINLY E LAKE SUPERIOR DURING THIS TIME. EXPECT A LOW NEAR MONTANA ON FRIDAY TO TRACK ACROSS THE N AND CENTRAL PLAINS SATURDAY MORNING...AND THE MID MISSISSIPPI VALLEY SATURDAY AFTERNOON...BEFORE DEEPENING NORTHEASTWARD ACROSS THE LOWER GREAT LAKES AND QUEBEC LATE SATURDAY NIGHT INTO SUNDAY. THIS WILL BRING A TROUGH THROUGH THE AREA SATURDAY NIGHT INTO SUNDAY...ALONG WITH THE POTENTIAL FOR N-NW GALES. HEAVY FREEZING SPRAY WILL ALSO MAKE A RETURN ACROSS MUCH OF LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ001-003. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 4 AM EST /3 AM CST/ EARLY THIS MORNING FOR LSZ162-240>245-248>251-263>267. GALE WARNING UNTIL 10 AM EST THIS MORNING FOR LSZ266-267. GALE WARNING UNTIL 7 AM EST /6 AM CST/ THIS MORNING FOR LSZ162- 241>251-263>265. HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST EARLY THIS MORNING FOR LSZ246-247. LAKE MICHIGAN... HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST EARLY THIS MORNING FOR LMZ221-248-250. GALE WARNING UNTIL 1 AM EST EARLY THIS MORNING FOR LMZ221-250. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...RJT MARINE...JLB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1259 AM EST THU JAN 1 2015 .SYNOPSIS... A COLD FRONT WILL BRING THE POTENTIAL FOR LAKE SNOWS NORTH OF THE NEW YORK THRUWAY THURSDAY NIGHT AND FRIDAY. ON SATURDAY AFTERNOON, A STORM SYSTEM WILL MOVE IN FROM THE OHIO VALLEY, BRINGING A MIX OF RAIN AND SNOW SATURDAY NIGHT. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 920 PM UPDATE... THE LAKE EFFECT SNOW BAND OVER THE NORTH COUNTRY IS PROGGED TO SKIRT NORTHERN ONEIDA COUNTY BETWEEN 7Z AND 10Z, BRINGING LIGHT SNOW ACCUMULATION. LATEST HRRR OUTPUT SUGGESTS A FEW FLURRIES OR LIGHT SNOW SHOWERS MAY SNEAK INTO NORTHWESTERN STEUBEN COUNTY OVERNIGHT, DUE TO A FLUCTUATING ERIE BAND. ADDED A SLIGHT CHC POP. INTERIOR VALLEY TEMPERATURES ARE ALREADY NEAR PROJECTED OVERNIGHT MINS, SO HAVE ADJUSTED MINS DOWNWARD. 1255 PM UPDATE... LAKE SNOWS HV EXITED NRN ONEIDA CNTY THUS HV CANCELLED THE WARNING. EXPECT LK EFFECT SNOW TO RMN WELL TO THE NORTH ON 240-250 FLOW THRU THE OVRNGT WITH A SLIGHT WOBBLE TO THE SOUTH POSSIBLE TWD 09Z WITH PERHAPS A FEW LGT SNOW SHOWERS AND/OR FLURRIES SNEAKING INTO EXTREME NRN ONEIDA THRU DAYBREAK. VRY MINIMAL ACCUMS ARE EXPECTED WITH THIS WOBBLE. EXPECTING THAT LK ERIE BAND WL STAY A TAD TOO FAR WEST TO AFFECT FINGER LAKES THIS EVNG INTO THE OVRNGT. NOTHING MORE THAN CLD CVR EXPECTED ON 240 DEGREE FLOW. EXPECT MINS TO DROP INTO THE LWR TEENS BY MRNG WITH SINGLE DIGITS POSSIBLE IN NOTORIOUSLY COLDER VALLEYS. && .SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/... 245 PM UPDATE... LAKE EFFECT SNOW WL RMN NORTH OF CWA FOR MOST OF TOMORROW. THERE IS SOME INDICATION THAT SNOW BAND WL MAKE A RUN TWD THE SOUTH ARND 18Z BUT QUICKLY RETREAT BACK TO THE NORTH AS WINDS BACK TWD THE SOUTH AHD OF APPCHG CDFNT. HV MAINLY CONFINED 20-30 POPS FOR LOCATIONS NORTH OF THE NY THRUWAY DRG THE AFTN HRS. AS WINDS GO SRLY TEMPS WL WARM INTO THE 20S BY AFTN, WRMR THAN TDA THO STILL BLO NRML VALUES. CDFNT WL SLIP SOUTH THRU SRN CANADA LATE THUR NGT WITH LK SNOWS DVLPNG AHD OF AND ALONG THIS BNDRY. MODELS SEEM TO BE IN PRETTY GOOD AGREEMENT WITH FROPA WITH ONLY SVR HRS DIFFERENCE ON TIMING. THUS EXPECT LK EFFECT SNOW SHOWERS TO COMMENCE LATE EVNG AND TWD MIDNIGHT WITH LKLY BAND OF SNOW SHOWERS DROPPING INTO NRN ONEIDA AFTER 08Z. WL ALLOW LATER SHIFTS TO GET A BETTER HANDLE ON ANY POTENTIAL HEADLINES FOR LK EFFECT EVENT TOMORROW NIGHT/FRI MRNG. GFS AND NAM DIFFER ON HOW LONG FLOW WL BE ALIGNED FOR FAVORABLE LK SNOWS ON FRIDAY. NAM PUSHES FRONT THRU QUICKLY AND ALLOWS DRIER AIR TO DISRUPT SNOWS DRG THE AFTN WHILE GFS KEEP INVERSION UP ARND 800MB DRG THE AFTN HRS WITH FAIRLY STEADY STATE 280 DEGREE FLOW. FEEL IT PRUDENT TO HOLD OFF ON ANY HEADLINES AT THIS TIME DUE TO VARYING DEGREES OF UNCERTAINTY. SFC HIPRES WL BEGIN BUILDING IN LATE FRI NGT THO SOME REMNANT SNOWS MAY STILL EXIST NORTH OF THE THRUWAY THRU 06Z SAT. QUIET WX EXPECTED UNTIL SYSTEM MVS IN FM THE SOUTH AFT 18Z SATURDAY. COLD AIR DAMMING PROGGED ACRS ERN ZONES THRU END OF SHORT TERM PD THUS PCPN WL MV IN AS ALL SNOW THRU 00Z SUN. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... MAIN FOCUS CONTINUES TO BE EARLY IN THE PERIOD WITH MED RANGE MODELS IN PRETTY GOOD SYNOPTIC AGREEMENT THAT A PHASING SOUTHERN STREAM/NORTHERN STREAM TROF WILL EJECT A SFC LOW THROUGH THE GREAT LAKES REGION AND EASTERN ONTARIO/QUEBEC ON SATURDAY NIGHT AND SUNDAY. THIS IS, OF COURSE, A TRACK THAT SIGNALS A SNOW-TO-MIX-TO-RAIN EVENT FOR CNY/NEPA...FOLLOWED BY A DRY SLOT AND SHOWERY PRECIPITATION ON THE BACK SIDE SUN-MON. GIVEN THE MODEL AGREEMENT AND TRENDS...THIS IS A FAIRLY HIGH CONFIDENCE EVENT SO WILL CONTINUE WITH CAT POP ALREADY OFFERED BY PREVIOUS FCST. BEYOND MONDAY...A BROAD UPPER LEVEL TROF RESIDENT ACROSS THE NORTHEAST AND GTLKS WILL MAINTAIN A COLD AND UNSTABLE WEST-NW FLOW WITH TRANSIENT UPPER LEVEL WAVES GENERATING PERIODS OF LAKE SNOW RESPONSES TO THE EAST OF ERIE AND ONTARIO. HAVE PRETTY MUCH CONSTANT CHANCES FOR SNOW SHOWERS OR FLURRIES GOING THROUGH WEDNESDAY. WITH THE EXCEPTION OF AN ABNORMALLY MILD SUNDAY...TEMPERATURES WILL BE AT OR BELOW NORMAL DURING THIS TIME. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... 06Z UPDATE... VFR STILL EXPECTED FOR THE NEXT 24 HOURS...EXCEPT LAKE EFFECT -SHSN DROPPING INTO KRME AND THEN KSYR 03Z-06Z FRIDAY WITH ASSOCIATED MVFR TO IFR VIS. UNTIL THEN...SCT-BKN CLOUDS AROUND 4-5 KFT FOR THE NY TERMINALS COURTESY OF LAKE ERIE MOISTURE CARRYING ACROSS...AND ONLY PATCHY HIGH CIRRUS FOR KAVP 15-25 KFT AGL. WINDS GENERALLY SW TO WSW 10-15 KTS WITH GUSTS DURING THE DAYTIME HOURS IN LOWER 20S KT RANGE. KSYR-KRME WINDS SLIGHTLY VEERING MORE WESTERLY TOWARDS END OF TAF PERIOD. OUTLOOK... FRI...LAKE EFFECT SNOW BAND IN VICINITY OF KRME-KSYR WITH ASSOCIATED IFR VIS AT TIMES. LOCALIZED BRIEF MVFR-IFR SNOW SHOWERS POSSIBLE KITH-KBGM. SAT/SAT NGT...BECOMING IFR WITH SNOW DEVELOPING...CHANGING TO WINTRY MIX AND OCNL RAIN/FRZG RAIN OVERNIGHT. SUN...VFR. SCT RAIN SHOWERS. MON...MVFR. SCT SNOW SHOWERS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...DJP/PVF NEAR TERM...DJP/PVF SHORT TERM...PVF LONG TERM...JAB AVIATION...MDP
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
900 AM MST THU JAN 1 2015 ...FREEZING TEMPERATURES LIKELY AT MANY LOWER DESERT LOCATIONS AGAIN TONIGHT... .SYNOPSIS... THE STRONG AND VERY COLD STORM SYSTEM THAT BROUGHT RAIN AND LOW ELEVATION SNOWFALL TO THE DESERT SOUTHWEST WILL SLOWLY MOVE OFF TO THE EAST TODAY. IN ITS WAKE...WELL BELOW NORMAL TEMPERATURES WILL PERSIST ACROSS THE REGION THROUGH SUNDAY. HIGH PRESSURE BUILDING IN FROM THE WEST WILL BRING A GRADUAL WARMING TREND FRIDAY THROUGH THE MIDDLE PART OF NEXT WEEK. && .DISCUSSION... AFTER A RATHER INTERESTING NEW YEAR/S EVE...WHICH SAW NUMEROUS REPORTS OF SNOW FLURRIES ACROSS THE GREATER PHX AREA JUST BEFORE MIDNIGHT...THIS MORNING HAS STARTED OUT ON THE COLD SIDE...WITH MOST OUTLYING LOWER DESERT LOCATIONS REPORTING LOWS AT/BELOW FREEZING. CURRENTLY...OUTSIDE OF SOME MID-LEVEL CLOUDINESS ACROSS SOUTH-CENTRAL ARIZONA...MOST AREAS ARE SEEING THE RETURN OF SUNNY TO PARTLY SUNNY SKIES. TODAY STILL APPEARS IT WILL BE A RATHER COLD ONE...WITH 850MB TEMPS REMAINING IN THE -2 TO -4C RANGE...SUPPORTING HIGH TEMPS ONLY IN THE MID-40 TO LOWER-50 RANGE...IN SPITE OF THE EXPECTED SUNSHINE. AS FAR AS THE VERY SHORT TERM IS CONCERNED...OTHER THAN SOME MINOR ADJUSTMENTS TO REDUCE POPS AND TO THE TEMP AND DEWPOINT GRIDS...CURRENT GRIDS AND ZONE FORECASTS STILL LOOK GOOD...AND NO FURTHER UPDATES ARE PLANNED. && .PREVIOUS DISCUSSION... WELL-DEFINED VORT MAX CONTINUES TO SLIDE EASTWARD ACROSS NORTHERN AZ EARLY THIS MORNING. ELONGATED BAND OF COOLER CLOUDS ASSOCIATED WITH STRONG JET AND VORTICITY-FORCED ASCENT HAS PUSHED STEADILY EASTWARD INTO NORTHERN AND EASTERN AZ. LAST GASP OF PRECIPITATION ACROSS THE PHOENIX AREA WAS IN THE FORM OF LIGHT SNOW ACROSS MANY SPOTS JUST BEFORE MIDNIGHT. EVEN IN THE LOWEST ELEVATIONS OF THE VALLEY...A MIX OF RAIN AND SNOW WAS OBSERVED. FOR THIS MORNING...GLOBAL AND HI-RES GUIDANCE INCLUDING THE HRRR ARE IN GOOD AGREEMENT THAT LIGHT SNOW WILL CONTINUE TO TAPER OFF ACROSS SOUTHERN GILA COUNTY WITH LITTLE ADDITIONAL ACCUMULATION. END TIME OF THE WINTER STORM WARNING FOR THE HIGHER ELEVATIONS OF SOUTHERN GILA COUNTY HAS BEEN TRIMMED TO 6 AM. WITH A SUBSIDENT FLOW EXPECTED...POPS WERE ALSO LOWERED ACROSS THESE AREAS AND IN THE LOWER DESERTS THROUGH THIS AFTERNOON. NEVERTHELESS...SCATTERED CLOUDS WILL WRAP AROUND THE DEPARTING LOW PRESSURE SYSTEM PRODUCING PARTLY CLOUDY SKIES AND ISOLATED SNOW FLURRIES. AFTER A VERY COLD MORNING...TEMPERATURES WILL AGAIN STRUGGLE TO REACH THE 50 DEGREE MARK...MARKING THE COLDEST MAX TEMPERATURES SINCE THE FREEZING EVENT IN JANUARY 2013. THE COLD AFTERNOON WILL SET THE STAGE FOR ANOTHER COLD NIGHT. MOSTLY CLEAR SKIES AND LIGHT WINDS IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM WILL PROMOTE RADIATIONAL COOLING AND A FREEZE WARNING REMAINS IN EFFECT FOR MUCH OF THE LOWER DESERTS INCLUDING THE PHOENIX AREA. LATEST STATISTICAL GUIDANCE HAS TRENDED SOMEWHAT COLDER AND IMPERIAL COUNTY WAS ALSO ADDED TO THE WARNING. OPERATIONAL MODELS REMAIN IN EXCELLENT AGREEMENT THROUGH THE EXTENDED...INDICATING THAT PACIFIC HIGH PRESSURE WILL BUILD ACROSS THE REGION. THIS WILL RESULT IN DRY CONDITIONS ALONG WITH INCREASING THICKNESSES AND A GRADUAL WARMING TREND THROUGH THE MIDDLE OF NEXT WEEK. HOWEVER...TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH MONDAY WITH COLD MORNINGS. A FREEZE WARNING MAY ULTIMATELY BE NEEDED FOR PORTIONS OF THE AREA AGAIN SATURDAY MORNING. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL... MOIST BOUNDARY LAYER CONDITIONS REMAIN ACROSS THE AREA WITH PATCHES OF LOW VFR STRATOCU PERSISTING ACROSS SOUTH-CENTRAL ARIZONA. THE STRATOCU DECK AT 4-5K FEET WILL AFFECT THE PHOENIX TERMINALS FOR A GOOD PORTION OF THIS MORNING AND POSSIBLY INTO THE AFTERNOON. CIGS FOR THIS AFTERNOON AND EVENING WILL RISE TO AROUND 6K FEET AND SHOULD BE MORE SCATTERED. LIGHT WINDS WILL DOMINATE THROUGH THE PERIOD AND GENERALLY FOLLOW TYPICAL DIURNAL WIND PATTERNS. SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... CLEAR TO MOSTLY CLEAR SKIES AND LIGHT WINDS WILL LAST THROUGH AT LEAST FRIDAY MORNING. NO AVIATION IMPACTS EXPECTED. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... SATURDAY THROUGH WEDNESDAY... A REBOUND IN TEMPERATURES WILL HAPPEN THIS WEEKEND INTO NEXT WITH HIGHS REACHING NORMALS BY NEXT MONDAY AND WARMING EVEN FURTHER BY NEXT WEDNESDAY. MINIMUM RELATIVE HUMIDITIES OF 15 TO 30 PERCENT ON SATURDAY WILL GRADUALLY LOWER THROUGH THE PERIOD WITH VALUES IN THE TEENS TO LOWER 20S FOR NEXT TUESDAY AND WEDNESDAY. WINDS WILL REMAIN LIGHT THROUGH THE PERIOD UNDER STRONG HIGH PRESSURE. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...FREEZE WARNING UNTIL 9 AM MST THIS MORNING AZZ020>022-026>028. FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM MST FRIDAY AZZ020>023-026>028. WINTER STORM WARNING UNTIL 6 AM MST EARLY THIS MORNING ABOVE 3500 FEET FOR AZZ024. CA...FREEZE WARNING UNTIL 8 AM PST THIS MORNING CAZ033. FREEZE WARNING FROM 10 PM THIS EVENING TO 8 AM PST FRIDAY CAZ033. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...PERCHA/HIRSCH AVIATION....KUHLMAN FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
512 AM MST THU JAN 1 2015 ...FREEZING TEMPERATURES LIKELY AT MANY LOWER DESERT LOCATIONS THIS MORNING AND AGAIN TONIGHT... .SYNOPSIS... THE STRONG AND VERY COLD STORM SYSTEM THAT BROUGHT RAIN AND LOW ELEVATION SNOWFALL TO THE DESERT SOUTHWEST WILL SLOWLY MOVE OFF TO THE EAST TODAY. IN ITS WAKE...WELL BELOW NORMAL TEMPERATURES WILL PERSIST ACROSS THE REGION THROUGH SUNDAY. HIGH PRESSURE BUILDING IN FROM THE WEST WILL BRING A GRADUAL WARMING TREND FRIDAY THROUGH THE MIDDLE PART OF NEXT WEEK. && .DISCUSSION... WELL-DEFINED VORT MAX CONTINUES TO SLIDE EASTWARD ACROSS NORTHERN AZ EARLY THIS MORNING. ELONGATED BAND OF COOLER CLOUDS ASSOCIATED WITH STRONG JET AND VORTICITY-FORCED ASCENT HAS PUSHED STEADILY EASTWARD INTO NORTHERN AND EASTERN AZ. LAST GASP OF PRECIPITATION ACROSS THE PHOENIX AREA WAS IN THE FORM OF LIGHT SNOW ACROSS MANY SPOTS JUST BEFORE MIDNIGHT. EVEN IN THE LOWEST ELEVATIONS OF THE VALLEY...A MIX OF RAIN AND SNOW WAS OBSERVED. FOR THIS MORNING...GLOBAL AND HI-RES GUIDANCE INCLUDING THE HRRR ARE IN GOOD AGREEMENT THAT LIGHT SNOW WILL CONTINUE TO TAPER OFF ACROSS SOUTHERN GILA COUNTY WITH LITTLE ADDITIONAL ACCUMULATION. END TIME OF THE WINTER STORM WARNING FOR THE HIGHER ELEVATIONS OF SOUTHERN GILA COUNTY HAS BEEN TRIMMED TO 6 AM. WITH A SUBSIDENT FLOW EXPECTED...POPS WERE ALSO LOWERED ACROSS THESE AREAS AND IN THE LOWER DESERTS THROUGH THIS AFTERNOON. NEVERTHELESS...SCATTERED CLOUDS WILL WRAP AROUND THE DEPARTING LOW PRESSURE SYSTEM PRODUCING PARTLY CLOUDY SKIES AND ISOLATED SNOW FLURRIES. AFTER A VERY COLD MORNING...TEMPERATURES WILL AGAIN STRUGGLE TO REACH THE 50 DEGREE MARK...MARKING THE COLDEST MAX TEMPERATURES SINCE THE FREEZING EVENT IN JANUARY 2013. THE COLD AFTERNOON WILL SET THE STAGE FOR ANOTHER COLD NIGHT. MOSTLY CLEAR SKIES AND LIGHT WINDS IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM WILL PROMOTE RADIATIONAL COOLING AND A FREEZE WARNING REMAINS IN EFFECT FOR MUCH OF THE LOWER DESERTS INCLUDING THE PHOENIX AREA. LATEST STATISTICAL GUIDANCE HAS TRENDED SOMEWHAT COLDER AND IMPERIAL COUNTY WAS ALSO ADDED TO THE WARNING. OPERATIONAL MODELS REMAIN IN EXCELLENT AGREEMENT THROUGH THE EXTENDED...INDICATING THAT PACIFIC HIGH PRESSURE WILL BUILD ACROSS THE REGION. THIS WILL RESULT IN DRY CONDITIONS ALONG WITH INCREASING THICKNESSES AND A GRADUAL WARMING TREND THROUGH THE MIDDLE OF NEXT WEEK. HOWEVER...TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH MONDAY WITH COLD MORNINGS. A FREEZE WARNING MAY ULTIMATELY BE NEEDED FOR PORTIONS OF THE AREA AGAIN SATURDAY MORNING. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL... MOIST BOUNDARY LAYER CONDITIONS REMAIN ACROSS THE AREA WITH PATCHES OF LOW VFR STRATOCU PERSISTING ACROSS SOUTH-CENTRAL ARIZONA. THE STRATOCU DECK AT 4-5K FEET WILL AFFECT THE PHOENIX TERMINALS FOR A GOOD PORTION OF THIS MORNING AND POSSIBLY INTO THE AFTERNOON. CIGS FOR THIS AFTERNOON AND EVENING WILL RISE TO AROUND 6K FEET AND SHOULD BE MORE SCATTERED. LIGHT WINDS WILL DOMINATE THROUGH THE PERIOD AND GENERALLY FOLLOW TYPICAL DIURNAL WIND PATTERNS. SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... CLEAR TO MOSTLY CLEAR SKIES AND LIGHT WINDS WILL LAST THROUGH AT LEAST FRIDAY MORNING. NO AVIATION IMPACTS EXPECTED. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... SATURDAY THROUGH WEDNESDAY... A REBOUND IN TEMPERATURES WILL HAPPEN THIS WEEKEND INTO NEXT WITH HIGHS REACHING NORMALS BY NEXT MONDAY AND WARMING EVEN FURTHER BY NEXT WEDNESDAY. MINIMUM RELATIVE HUMIDITIES OF 15 TO 30 PERCENT ON SATURDAY WILL GRADUALLY LOWER THROUGH THE PERIOD WITH VALUES IN THE TEENS TO LOWER 20S FOR NEXT TUESDAY AND WEDNESDAY. WINDS WILL REMAIN LIGHT THROUGH THE PERIOD UNDER STRONG HIGH PRESSURE. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...FREEZE WARNING UNTIL 9 AM MST THIS MORNING AZZ020>022-026>028. FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM MST FRIDAY AZZ020>023-026>028. WINTER STORM WARNING UNTIL 6 AM MST EARLY THIS MORNING ABOVE 3500 FEET FOR AZZ024. CA...FREEZE WARNING UNTIL 8 AM PST THIS MORNING CAZ033. FREEZE WARNING FROM 10 PM THIS EVENING TO 8 AM PST FRIDAY CAZ033. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...HIRSCH AVIATION....KUHLMAN FIRE WEATHER...KUHLMAN
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
335 AM MST THU JAN 1 2015 ...FREEZING TEMPERATURES LIKELY AT MANY LOWER DESERT LOCATIONS THIS MORNING AND AGAIN TONIGHT... .SYNOPSIS... THE STRONG AND VERY COLD STORM SYSTEM THAT BROUGHT RAIN AND LOW ELEVATION SNOWFALL TO THE DESERT SOUTHWEST WILL SLOWLY MOVE OFF TO THE EAST TODAY. IN ITS WAKE...WELL BELOW NORMAL TEMPERATURES WILL PERSIST ACROSS THE REGION THROUGH SUNDAY. HIGH PRESSURE BUILDING IN FROM THE WEST WILL BRING A GRADUAL WARMING TREND FRIDAY THROUGH THE MIDDLE PART OF NEXT WEEK. && .DISCUSSION... WELL-DEFINED VORT MAX CONTINUES TO SLIDE EASTWARD ACROSS NORTHERN AZ EARLY THIS MORNING. ELONGATED BAND OF COOLER CLOUDS ASSOCIATED WITH STRONG JET AND VORTICITY-FORCED ASCENT HAS PUSHED STEADILY EASTWARD INTO NORTHERN AND EASTERN AZ. LAST GASP OF PRECIPITATION ACROSS THE PHOENIX AREA WAS IN THE FORM OF LIGHT SNOW ACROSS MANY SPOTS JUST BEFORE MIDNIGHT. EVEN IN THE LOWEST ELEVATIONS OF THE VALLEY...A MIX OF RAIN AND SNOW WAS OBSERVED. FOR THIS MORNING...GLOBAL AND HI-RES GUIDANCE INCLUDING THE HRRR ARE IN GOOD AGREEMENT THAT LIGHT SNOW WILL CONTINUE TO TAPER OFF ACROSS SOUTHERN GILA COUNTY WITH LITTLE ADDITIONAL ACCUMULATION. END TIME OF THE WINTER STORM WARNING FOR THE HIGHER ELEVATIONS OF SOUTHERN GILA COUNTY HAS BEEN TRIMMED TO 6 AM. WITH A SUBSIDENT FLOW EXPECTED...POPS WERE ALSO LOWERED ACROSS THESE AREAS AND IN THE LOWER DESERTS THROUGH THIS AFTERNOON. NEVERTHELESS...SCATTERED CLOUDS WILL WRAP AROUND THE DEPARTING LOW PRESSURE SYSTEM PRODUCING PARTLY CLOUDY SKIES AND ISOLATED SNOW FLURRIES. AFTER A VERY COLD MORNING...TEMPERATURES WILL AGAIN STRUGGLE TO REACH THE 50 DEGREE MARK...MARKING THE COLDEST MAX TEMPERATURES SINCE THE FREEZING EVENT IN JANUARY 2013. THE COLD AFTERNOON WILL SET THE STAGE FOR ANOTHER COLD NIGHT. MOSTLY CLEAR SKIES AND LIGHT WINDS IN THE WAKE OF THE DEPARTING LOW PRESSURE SYSTEM WILL PROMOTE RADIATIONAL COOLING AND A FREEZE WARNING REMAINS IN EFFECT FOR MUCH OF THE LOWER DESERTS INCLUDING THE PHOENIX AREA. LATEST STATISTICAL GUIDANCE HAS TRENDED SOMEWHAT COLDER AND IMPERIAL COUNTY WAS ALSO ADDED TO THE WARNING. OPERATIONAL MODELS REMAIN IN EXCELLENT AGREEMENT THROUGH THE EXTENDED...INDICATING THAT PACIFIC HIGH PRESSURE WILL BUILD ACROSS THE REGION. THIS WILL RESULT IN DRY CONDITIONS ALONG WITH INCREASING THICKNESSES AND A GRADUAL WARMING TREND THROUGH THE MIDDLE OF NEXT WEEK. HOWEVER...TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH MONDAY WITH COLD MORNINGS. A FREEZE WARNING MAY ULTIMATELY BE NEEDED FOR PORTIONS OF THE AREA AGAIN SATURDAY MORNING. && .AVIATION... SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL... BROAD AREA OF LOWER LEVEL STRATUS COVERS MUCH OF THE LOWER CENTRAL AZ DESERTS...WITH VARYING LAYERS AND BREAKS IN THE CLOUD DECK. WILL LOOK FOR PERIODS OF MVFR CIGS AT PHX AREA TERMINALS THROUGH THE EVENING...BUT CONDITIONS WILL NOT REMAIN AS SOCKED IN AS THEY WERE DURING THE DAY. CIGS AROUND THE 5500-6000FT LAYER MAY HOLD THROUGH SUNRISE AND TERRAIN OBSCURATIONS WILL ALSO PERSIST. WX RADAR SCOPES STILL SHOW SCATTERED LIGHT SHOWERS OVER EASTERN PORTIONS OF THE PHX METRO THAT MAY PASS OVER THE TERMINALS...BRIEFLY REDUCING CIGS BUT NOT AMOUNTING TO MUCH BY WAY OF WETTING TARMAC/APRON SFCS. WESTERLY WINDS 10KTS OR LESS WILL HOLD INTO THE OVERNIGHT HOURS...BEFORE ATTEMPTING TO SWITCH TO EASTERLY NEAR OR AFTER 01/12Z...OTHERWISE BECOME VARIABLE WITH SPEEDS 6 KTS OR LESS. GIVEN THE COOLING AIRMASS AND ELEVATED DEWPOINTS...EXPECT ATLEAST VCFG NEAR KIWA AND KSDL BY SUNRISE...WITH LESS CONFIDENCE OF ANY SUBSTANTIAL FOG DEVELOPING NEAR KPHX. SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH... PATCHES OF LOW TO MID LEVEL CIGS CONTINUE TO CIRCULATE AROUND THE UPPER LOW THAT HAS NOW PUSHED INTO NW AZ. CIGS GNLY WILL HOLD ABOVE 8KFT FOR THE REMAINDER OF THE EVENING AS SOME DRIER AIR CONTINUES TO WORK INTO THE REGION. WINDS TO HOLD NORTHERLY HEADINGS WHILE SUBSIDING IN THEIR ELEVATED SPEEDS...OCCASIONALLY BECOMING NEAR CALM AS SKIES CLEAR BY SUNRISE. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... FRIDAY THROUGH TUESDAY... MOSTLY CLEAR SKIES AND MUCH BELOW NORMAL TEMPERATURES ARE EXPECTED FRIDAY THROUGH SUNDAY...WARMING SOMEWHAT MONDAY AND TUESDAY. MINIMUM RELATIVE HUMIDITIES FRIDAY WILL RANGE FROM 20 PERCENT IN SOUTHEAST CALIFORNIA TO 50 PERCENT IN SOUTHERN GILA COUNTY...DECREASING MONDAY AND TUESDAY BY 15 TO 20 PERCENT RANGE AREA-WIDE. LIGHT WIND. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...FREEZE WARNING UNTIL 9 AM MST THIS MORNING AZZ020>022-026>028. FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM MST FRIDAY AZZ020>023-026>028. WINTER STORM WARNING UNTIL 6 AM MST EARLY THIS MORNING ABOVE 3500 FEET FOR AZZ024. CA...FREEZE WARNING UNTIL 8 AM PST THIS MORNING CAZ033. FREEZE WARNING FROM 10 PM THIS EVENING TO 8 AM PST FRIDAY CAZ033. && $$ VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX DISCUSSION...HIRSCH AVIATION....NOLTE FIRE WEATHER...VASQUEZ
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
502 AM MST THU JAN 1 2015 .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 406 AM MST THU JAN 1 2015 SATELLITE AND RADAR SIGNATURES FINALLY SHOWING SOME PROMISE ACROSS OUR SOUTHWEST CWA EARLY THIS MORNING. THIS IS A LATER START THAN EXPECTED. SNOW TOTALS ARE LIKELY GOING TO BE LESS THAN EARLIER THOUGHT...BUT LOOKING AT BLANDING WEB CAM...THIS STORM IS LIKELY TO IMPACT TRAVEL ON THIS HOLIDAY OVER A GOOD CHUNK OF OUR CWA. THE NEXT 6 TO 12 HOURS WILL BE THE MOST ACTIVE PERIOD ACROSS OUR CWA AND WILL LET THE CURRENT HIGHLIGHTS RUN. LARGE SCALE ASCENT IS INCREASING SIGNIFICANTLY OVER THE 4 CORNERS AS THE UPPER JET MAX IS FINALLY REFORMING ON THE DOWNSTREAM SIDE OF THE CYCLONE AND ALLOWING IT TO SLOG EASTWARD. THE CYCLONIC JET IS AIDING IN THE STRONG UPWARD MOTION AND AN INVERTED TROF EXTENDING FROM THE 4 CORNERS TO THE CENTRAL MOUNTAINS IS AIDING IN LOW LEVEL CONVERGENCE OVER SOUTHEAST UTAH AND SOUTHWESTERN COLORADO THIS MORNING. QG FIELDS SUGGEST THE ASCENT INCREASES AND TIGHTENS THROUGH MID MORNING NEAR THE 4 CORNERS...THEN RELAXES THROUGH THE DAY AS MID LEVEL CIRCULATION IS ELONGATED BY THE RETREATING JET MAX. SOUTHERLY OROGRAPHICS ARE LIKELY TO AID IN FOCUSING HEAVIER SNOW IN THE FOOTHILLS AND HILLS OF THE SOUTHERN SAN JUANS WITH THE LOW JUST TO THE WEST THIS MORNING. UNFORTUNATELY INSTABILITY WILL NOT BE AS STRONG AS ANTICIPATED 24 HOURS AGO. BOTH MODELS SHOW BOTH A MID LEVEL AND LOW LEVEL CIRCULATION RUNNING ALONG THE INVERTED TROUGH AXIS AND THIS SHOULD BRING SNOW ACROSS THE CENTRAL MOUNTAINS AND VALLEYS THROUGH THE EARLY EVENING...THOUGH OROGRAPHICS SLACKEN LATER TODAY. DID BOOST POPS AND SNOW AMOUNTS ACROSS THE WEST ELKS...ELKS AND TOP OF THE MESA. LOOKING AT THE LATEST BUFKIT SOUNDING DATA AND SREF PLUMES ALSO THINK SOME HIGH VALLEY LOCATIONS MAY PICK UP SOME SNOW THIS AFTERNOON. THIS INCLUDES ASPEN WHICH IS NEAR THE PASSING SURFACE LOW AND GUNNISON WHERE AMOUNTS WILL GENERALLY BE 2-3 INCHES. DECIDED AGAINST AN ADVISORY AT THIS TIME WITH THE HIGH PASSES CLOSED...THE ONLY CONCERN WOULD BE AT MCCLURE BUT CONFIDENCE TOO LOW ATTM. THE LOW CONTINUES TO ELONGATE TONIGHT WITH THE GFS AND NAM NOW TAKING DIFFERENT CAMPS ON WHERE THE MAIN CIRCULATIONS REMAIN IN THIS AREA OF LOW PRESSURE. GFS DEVELOPS ONE SOUTHERN UTAH AND THE NAM THE PLAINS OF COLORADO. EITHER WAY AN EASTERLY COMPONENT TO THE WINDS OCCUR WHICH MAY KEEP SOME ISOLATED SHOWERS GOING WITH RESIDUAL MOISTURE AROUND FOR THE MOST PART THIS STORM IS DONE BY MIDNIGHT. THE DENDRITIC LAYER DRIES OUT IN THE FAVORED GFS SOLUTION AND THIS LEAD TO A QUIET BUT COLD FRIDAY AND NEW SNOW HOLDS THE INVERSION IN. TEMPERATURES REMAIN COLD AND WELL BELOW NORMAL. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 406 AM MST THU JAN 1 2015 THE NEXT PROGRESSIVE SHORT WAVE ARRIVES FROM THE NORTHWEST WITH INCREASING CLOUDS ACROSS THE NORTH ON FRIDAY NIGHT. THE BEST DYNAMICAL FORCING ARRIVES SATURDAY...COINCIDING WITH SOME MID LEVEL COLD ADVECTION. THE NORTHERN COLORADO MOUNTAINS WILL BE THE PRIMARY BENEFICIARY FOR SNOW...BUT COULD EXTEND AS FAR SOUTH AS THE NWRN SAN JUAN MOUNTAINS. MODEL QPF AMOUNTS SUGGEST SNOW AMOUNTS MOSTLY IN THE 5-10 INCH RANGE FOR THE NWRN COLORADO MOUNTAINS. A LITTLE CONCERN THAT THE TRAPPED COLD AIR AND SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER COULD ENHANCE SNOW AMOUNTS. ABOVE TIMBERLINE OR EXPOSED AREAS WILL BE PRONE FOR BLOWING SNOW AS 700 MB GRADIENT FLOW WILL BE AROUND 30 KTS. WITH THE MODERATELY DEEP SURFACE LOW TRACKING WELL NORTH OF COLORADO (ACROSS MONTANA AND THE DAKOTAS)...THIS REDUCES THE LIKELIHOOD OF SIGNIFICANT HEAVY SNOW (MEANING 12+ INCHES) FOR NORTHWEST COLORADO. THE SNOW THREAT DECREASES FARTHER WEST AND SOUTH. PACIFIC MOISTURE CONTINUES TO STREAM OVER THE NRN COLORADO MOUNTAINS FOR SOME OROGRAPHIC SNOWFALL INTO MONDAY. THIS MOISTURE FEED IS NOT DEEP WITH SPOTTY LIGHT AMOUNTS FOR NORTHERN ROUTT COUNTY. THE PASSAGE OF SATURDAYS SHORT WAVE IS STRONG ENOUGH TO CAUSE SOME MIXING AND WEAKEN TEMPERATURE INVERSIONS. A WARMING TREND SHOULD PERSIST INTO NEXT WEDNESDAY. THE RATE OF WARMING TENDS TO BE PROBLEMATIC SINCE MANY VALLEYS ARE SNOW COVERED...BUT THE PATTERN DOES NOT FAVOR A STAGNANT AIR MASS WITH WNW FLOW PREVAILING OVER THE FORECAST AREA (WITH THE MAIN JET NORTH OF COLORADO). THE RIDGE AXIS WILL BE POSITIONED OVER THE WEST COAST STATES AND NOT OVERHEAD...SO THIS SHOULD RESULT IN SOME TEMPERATURE MODERATION. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 502 AM MST THU JAN 1 2015 WIDESPREAD -SN (OR OCCASIONAL MODERATE SNOW) WITH IFR CIGS ACROSS ACROSS SERN UTAH AND SWRN COLORADO TODAY. THE I70 CORRIDOR OR KGJT...KRIL...KASE...KEGE WILL BE ON THE NRN FRINGE OF THIS REGION OF SNOW. CURRENT HRRR MODEL KEEPS LIGHT SNOW FROM IMPACTING THESE TAF SITES WITH THE EXCEPTION OF KASE. KASE MAY TEMPORARILY FALL BELOW ILS BREAKPOINTS THIS AFTERNOON AND INTO THE EVENING HOURS. SLOW IMPROVEMENT AFTER 00Z WITH LIGHT TO MODERATE SNOW DECREASING ACROSS SW COLORADO. VFR IS EXPECTED TO PREVAIL NORTH OF INTERSTATE 70. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ018- 020. WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ019- 021>023. UT...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR UTZ028. WINTER STORM WARNING UNTIL 6 PM MST THIS EVENING FOR UTZ022-029. && $$ SHORT TERM...15 LONG TERM...PF AVIATION...PF
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
426 AM MST THU JAN 1 2015 .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 425 AM MST THU JAN 1 2015 A CLOSED MID-UPPER LOW OVER NORTH CENTRAL ARIZONA AT 09Z WILL BECOME INCREASINGLY ELONGATED ACROSS COLORADO AS IT SHIFTS EASTWARD ACROSS THE FOUR CORNERS REGION TODAY. AT THE SFC...AN EXPANSIVE AREA OF HIGH PRESSURE LINKED TO AN ARCTIC AIRMASS COVERS THE GREAT PLAINS. MODELS SHOW PRECIP FORMING NORTHEASTWARD ALONG THE 700-500MB TROUGH DEFORMATION AXIS REACHING THE SOUTHWEST CORNER OF THE FORECAST AREA BY LATE THIS MORNING. FORWARD SPEED OF CLOUD SHIELD WRAPPING AROUND THE UPPER LOW WILL LIKELY ARRIVE SOONER THAN THAT BASED ON SPEED OF MOTION MEASUREMENTS USING IR SATELLITE IMAGERY. EXCEPT FOR A BAND OF CIRRUS CLOUD STREAKING NEWRD ACRS THE SOUTHEAST CORNER OF THE CWA...SKIES AT THE PRESENT TIME WERE CLEAR ACROSS N-CENTRAL/NORTHEAST COLORADO. HRRR AND RAP MDLS SHOW LIGHT SNOWFALL/QPF OVER THE MOSQUITO...TEN MILE AND SOUTHERN FRONT RANGE MTNS BY MIDDAY...THEN SPREADING NORTHWARD OVER THE FRONT RANGE AND EASTWARD ALONG THE PALMER DIVIDE AND SOUTHERN SECTIONS OF THE I-25 URBAN CORRIDOR DURING THE LATE AFTERNOON HOURS. FORECASTED PCPN AMTS IN THIS AREA RANGE FROM A TRACE TO 0.20 INCH BY 00Z/FRI...AND SNOW AMOUNTS FROM A TRACE TO 3 INCHES. THE HEAVIER AMTS WILL BE FOUND OVER THE HIGHER TERRAIN SURROUNDING SOUTH PARK AND ALONG HIGHER PORTIONS OF THE PALMER DIVIDE IN DOUGLAS COUNTY. BY EVENING WITH THE UPPER LOW WEAKENING AND TURNING SOUTHEAST AWAY FROM COLORADO... SHOULD SEE A MARKED DECREASE IN SNOWFALL ACROSS SOUTHERN SECTIONS OF THE CWA BY MID TO LATE EVENING. AS THIS IS TAKING PLACE...MODELS NAMELY THE NAM...SHOW A SECONDARY AREA OF SNOWFALL DEVELOPING OVER THE NORTHERN FRONT RANGE MTN AND NRN I-25 URBAN CORRIDOR AS A RESULT OF OROGRAPHIC LIFT AND COLD ADVECTION OCCURRING ON THE NORTHERN FRINGE OF THE UPPER TROUGH. COULD SEE LOCAL SNOW AMTS UP TO AN INCH OR SO OVER HIGHER ELEVATIONS OF THE NRN FRONT RANGE AND POSSIBLY A QUARTER INCH OR SO ON THE NEARBY PLAINS BEFORE SKIES CLEAR AROUND 10Z/FRI. HIGH TEMPERATURES TODAY ARE EXPECTED TO BE A FEW DEGS COOLER THAN YESTERDAY DUE IN LARGE PART TO THE LACK OF SUNSHINE THIS AFTERNOON. WHEREAS TEMPS TONIGHT NOT AS COLD AS PREVIOUS NIGHTS BECAUSE OF CLOUD COVER AND AS A RESULT OF MIXED BNDRY LAYER DUE TO PCPN IN THE AREA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 425 AM MST THU JAN 1 2015 THE UPPER LOW NOW OVER ARIZONA WILL WEAKEN AND BECOME ELONGATED ACROSS COLORADO EARLY FRIDAY MORNING. A PIECE OF THIS LOW SEPARATES FROM THE PARENT SYSTEM WHICH WILL REMAIN OVER NEW MEXICO THROUGH FRIDAY NIGHT. STILL EXPECT A FAIR AMOUNT OF CLOUDINESS FRIDAY AM BUT ANY PRECIP WILL HAVE FINISHED DURING THE EARLY MORNING HOURS. TEMPERATURES WILL STILL REMAIN IN THE 30S ACROSS LOWER ELEVATIONS. THE MAIN LOW OVER NEW MEXICO IS PROGGED TO LIFT NORTHEAST INTO THE CENTRAL PLAINS ON SATURDAY WHILE A SECONDARY WAVE MOVES RAPIDLY SOUTHEAST FROM THE NORTHERN ROCKIES. AN ACCOMPANIED COLD FRONT EXPECTED TO BLAST ACROSS THE NORTHEAST PLAINS AROUND MIDDAY SATURDAY WITH A BRIEF PERIOD OF UPSLOPE FLOW ON SATURDAY AFTERNOON AND QUICK SHOT OF QG UPWARD FORCING AS STRONG JET MOVES ACROSS COLORADO. WILL CONTINUE TO INCREASE POPS SLIGHTLY DURING THIS PERIOD AS CONDITIONS CONTINUE TO LOOK MORE FAVORABLE FOR A SHOT OF SNOW OVER MOUNTAINS AND PLAINS. FOR SUNDAY AND INTO EARLY NEXT WEEK....THE PATTERN WILL SHIFT TO A STRONG NORTHWEST FLOW ALOFT. THIS WILL RESULT IN INCREASING WINDS OVER MOUNTAINS AND EAST SLOPES WITH A DOWNSLOPE WARMING TREND OVER THE NORTHEAST PLAINS. GIVEN THE FLOW PATTERN EXPECT SOME SNOW SHOWERS TO CONTINUE OVER THE HIGHER ELEVATIONS OF THE NORTHERN MOUNTAINS BUT ONLY MINIMAL ACCUMULATIONS. && .AVIATION...(FOR THE TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 425 AM MST THU JAN 1 2015 VFR CONDITIONS AT DENVER AREA TERMINALS THIS MORNING WILL DETERIORATE TO MVFR CONDITIONS WITH LOWERING CIGS TO AROUND 4000-5000 FT AGL AND SCATTERED AREAS OF LIGHT SNOWFALL REDUCING VSBYS TO 3-5 MILES AFTER 4 PM MST. KAPA COULD POSSIBLY SEE ILS CONDITIONS WITH CIGS LOWERING TO BELOW 3000 FEET AGL AND VSBYS BELOW 3 MILES WITH LIGHT TO MODERATE SNOWFALL LATE THIS AFTERNOON AND EARLY THIS EVENING. CONDITIONS SHOULD IMPROVE AT ALL TERMINALS AFTER 04Z THIS EVENING WITH CLEARING SKIES BEFORE MORNING. LIGHT S-SWLY WINDS EARLY TO MID-MORNING EXPECTED TO BECOME W-NWLY BY LATE MORNING BEFORE RETURNING TO A S-SWLY DIRECTION THIS EVENING. MOST AREAS SHOULD SEE WIND SPEEDS REMAINING UNDER 12 KTS. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BAKER LONG TERM...ENTREKIN AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS MIAMI FL
1004 AM EST THU JAN 1 2015 .UPDATE... SCATTERED SHOWERS REMAIN THIS MORNING MAINLY ACROSS THE ATLANTIC WATERS OFF THE PALM BEACHES. WEAK STATIONARY FRONT REMAINS DRAPED ACROSS THE AREA THIS MORNING CONTRIBUTING TO THE SHOWERS AND EXTENSIVE CLOUDINESS. LATEST VISIBLE SATELLITE DOES HOWEVER SHOW CLOUD SHIELD BEGINNING TO ERODE ACROSS BROWARD AND MIAMI-DADE COUNTIES LATE THIS MORNING. THIS HAS ALLOWED TEMPERATURES TO SURGE INTO THE MID TO UPPER 70S ALREADY. HRRR CONTINUES TO DEPICT ISOLATED LIGHT SHOWERS ACROSS MAINLY THE EASTERN HALF OF THE AREA INTO THE EARLY AFTERNOON HOURS...SO KEPT SLIGHT CHANCE POP GOING. THE REMAINDER OF THE FORECAST LOOKS ON TRACK AT THIS TIME. UPDATE SENT. && .PREV DISCUSSION... /ISSUED 649 AM EST THU JAN 1 2015/ AVIATION... WEAK LOW PRESSURE OVER SOUTHWEST FLORIDA IN COMBINATION WITH DIFFUSE FRONT NEAR LAKE OKEECHOBEE KEEPING PLENTY OF CLOUDS AND IFR/MVFR CONDITIONS IN BOTH CEILINGS AND VISIBILITY (MIXTURE OF SHOWERS AND FOG) ACROSS SOUTH FLORIDA THIS MORNING. BAND OF SHOWERS NEAR FLL/PBI AREA HAS STAYED MOSTLY OFFSHORE WITH LIGHT SHOWERS REACHING THE TERMINAL SITES. EXPECT THESE CONDITIONS TO PERSIST THROUGH ABOUT 15Z, FOLLOWED BY SLOW IMPROVEMENT AS THE LOW PRESSURE MOVES INTO THE GULF AND THE FRONT CONTINUES TO DISSIPATE. BY 18Z, EXPECT VFR CONDITIONS TO ONCE AGAIN PREVAIL WITH WIND FLOW BECOMING LIGHT SE (EXCEPT SEA BREEZE AT KAPF). THIS WILL ALSO INTRODUCE SLIGHTLY DRIER AIR TO THE AREA WITH COVERAGE OF SHOWERS DECREASING AS A RESULT. BY THIS EVENING, MOST OF AREA SHOULD BE FREE OF PRECIPITATION. SOME FOG/LOW CLOUDS COULD ONCE AGAIN FORM LATE TONIGHT AFTER 06Z, MAINLY INTERIOR AND WESTERN SECTIONS OF THE PENINSULA. /MOLLEDA PREV DISCUSSION... /ISSUED 319 AM EST THU JAN 1 2015/ DISCUSSION... A COMPACT AND WEAK MESOSCALE LOW PASSED SOUTHWARD ACROSS THE ATLANTIC WATERS YESTERDAY ALONG PALM BEACH COUNTY THEN DRIFTED WESTWARD ACROSS THE SOUTH FLORIDA PENINSULA EARLY THIS MORNING. DURING THE EARLY MORNING HOURS SCATTERED SHOWER ACTIVITY OCCURRED WITH THE GREATEST COVERAGE ACROSS NORTHERN BROWARD COUNTY AND ACROSS PALM BEACH COUNTY AND ADJACENT ATLANTIC WATERS...WITH THIS COVERAGE CONTINUING. THE COMBINATION OF LOW STRATUS AND/OR FOG WILL CONTINUE EARLY THIS MORNING WITH MOST OF THE COVERAGE EXPECTED ACROSS MIAMI DADE COUNTY AND SOUTHERN HALF OF BROWARD COUNTY. THE WILL BE A CHANCE OF RIP CURRENTS TODAY BUT MAINLY EXPECTED ACROSS THE PALM BEACH COUNTY BEACHES. THE LATEST MODEL GUIDANCE INDICATES A WEAK SURFACE TROUGH AND DIFFUSE FRONTAL BOUNDARY CONTINUING ACROSS THE SOUTH FLORIDA PENINSULA TODAY WITH HIGH PRESSURE THEN STARTING TO BUILD BACK ACROSS THE REGION THIS EVENING AND OVER NIGHT. THE FORECAST FOR TODAY IS FOR ISOLATED TO SCATTERED SHOWERS MAINLY ACROSS THE ATLANTIC WATERS AND THE ATLANTIC METRO AREAS WITH THE GREATEST COVERAGE CONTINUING TO BE ACROSS BROWARD AND PALM BEACH COUNTIES AND THE ADJACENT ATLANTIC WATERS. A DRYING TREND IS THEN FORECAST WITH THE MODEL CONSENSUS INDICATING SOUTHERLY LOW LEVEL FLOW BRINGING IN DRIER AIR INTO THE REGION TONIGHT INTO FRIDAY. BY FRIDAY HIGH PRESSURE WILL PREVAIL ACROSS THE REGION WITH A SURFACE RIDGE EAST OF THE FLORIDA PENINSULA AND AT THE MID TO UPPER LEVELS A LARGE AMPLITUDE RIDGE BECOMING ESTABLISHED ACROSS THE FLORIDA STRAITS. THIS PATTERN WILL MORE OR LESS PERSIST THROUGH THE UPCOMING WEEKEND...WITH STABLE WEATHER CONDITIONS AND INCREASINGLY WARMER TEMPERATURES PREVAILING ACROSS THE REGION. FOR THE EXTENDED FORECAST...THE GLOBAL MODEL CONSENSUS INDICATES THE NEXT COLD FRONT ENTERING THE FLORIDA PANHANDLE AND NORTHERN FLORIDA ON SUNDAY AND THEN INTO CENTRAL FLORIDA ON MONDAY AND APPROACHING LAKE OKEECHOBEE AND WEAKENING MONDAY NIGHT. BY TUESDAY THE MODELS START TO DIVERGE IN THEIR SOLUTIONS...BUT OVER ALL NO SIGNIFICANT IMPACTS ARE FORECAST THUS FAR FOR SOUTH FLORIDA WITH THE FORECAST INDICATING JUST A GRADUAL COOL DOWN AND POSSIBLY SOME ISOLATED SHOWER ACTIVITY. /BD MARINE... THE LOCAL PRESSURE GRADIENT ACROSS THE REGION EARLY THIS MORNING IS SUCH THAT WINDS IN THE 15 TO 20 KNOT RANGE ARE FORECAST ACROSS THE ATLANTIC WATERS MAINLY TO THE EAST OF PALM BEACH COUNTY AND ACROSS THE OFF SHORE WATERS...WITH AN SCEC FOR THESE WATERS TODAY. THE PRESSURE GRADIENT AND RESULTANT WINDS EAST OF PALM BEACH COUNTY IS FORECAST TO RELAX TONIGHT INTO FRIDAY. FOR THE REMAINDER OF THE OF THE FORECAST...WINDS AND SEAS ACROSS THE GULF AND ATLANTIC WATERS ARE FORECAST TO REMAIN WELL BELOW ADVISORY LEVELS. /BD && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 80 70 81 73 / 30 10 10 10 FORT LAUDERDALE 80 72 81 73 / 20 10 10 10 MIAMI 81 71 81 73 / 20 10 10 10 NAPLES 79 67 81 68 / 10 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ UPDATE...10/CD
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
937 AM EST Thu Jan 1 2015 .Near Term [Through Today]... Morning satellite imagery shows mid and high clouds streaming eastward ahead of an upper level trough over the southwest states. There is also an area of low clouds across portions of the southeast big bend and south-central Georgia. In between these two areas around Tallahassee, skies are mostly sunny. Some of the hi-res guidance such as the 11z HRRR keeps low clouds around the southeast big bend well into the afternoon hours, and if that occurs we will end up with another interesting high temperature distribution across the area today. It is possible that the warmest temperatures today will be across the central areas away from the high clouds to the west and low clouds to the east. Clouds will increase across the entire area tonight from west to east ahead of a developing warm front across the northern Gulf coast. && .Aviation... [Through 12z Friday] VFR conditions are expected to prevail for today across most of the area with light winds. The exception will be around VLD which will be on the edge of an MVFR cloud deck through this morning. MVFR conditions may return to the entire area tonight as moisture increases to the north of a developing warm front. && .Prev Discussion [423 AM EST]... .Short Term [Tonight Through Saturday]... There will be an upper level ridge over the region during this time. At the sfc, a weak high will be over the Southeast on Friday. By Saturday, a low from the Gulf will move through the lower MS River Valley. This low will strengthen quickly as it is supported in the upper levels by a deep trough moving out of the Southwest states. A warm front will pass through on Saturday bringing a chance for rain well ahead of the low, particularly in the northwestern part of the CWA. Expect cloudy skies with ample moisture from the Atlantic on Friday, then from the Gulf when winds become southerly on Saturday. Lows will be in the 40s on Friday morning and 50s on Saturday morning. Highs will range from the mid 60s to the lower 70s on Friday. Highs will be in the 70s on Saturday. .Long Term [Saturday Night Through Thursday]... By Sunday morning a strong low at the sfc will be over the Great Lakes region. A cold front will extend all the way to the Gulf Coast. Rain with some thunder is expected Sunday into Sunday night as the front moves through. On Monday high pressure will move in from the west bringing cooler, drier air. No rain is expected for the rest of the period as high pressure dominates the region. Temps will shift to seasonal levels after FROPA (50s/60s for highs and 30s/40s for lows). .Marine... Light to moderate northeasterly winds will turn southerly by Saturday. Cautionary level winds are possible on Saturday ahead of a cold front. Advisory level winds are possible on Monday after the cold front passes. .Fire Weather... No fire weather concerns are expected over the next several days as afternoon relative humidities will continue to remain well above any Red Flag concerns. .Hydrology... Most of the rivers across the region are slowly subsiding after last week`s heavy rainfall. Even the Withlacoochee river near Pinetta has leveled off, and will likely drop into action stage later today. While rivers outside the lower Withlacoochee/Suwannee area will continue to fall to below flood stage, this upcoming weekend`s rainfall totals may not be quite as high as earlier thought, especially where the current stages and potential problems would be the highest. At present, storm total QPF is expected to range from around 0.5 inches over the Suwannee and Withlacoochee basins, with a gradual increasing trend to the N and W. The highest totals of 1.5" to 2.5" appear likely over far western portions of the FL Panhandle as well as SE AL, which fortunately contain the basins which can handle those amounts of rainfall over a short period of time without too many concerns. Detailed information pertaining to current river stages and forecasts can be found at: http://water.weather.gov/ahps. && .Preliminary Point Temps/PoPs... Tallahassee 66 48 70 57 78 / 10 20 30 20 20 Panama City 63 53 68 61 74 / 0 20 40 30 40 Dothan 59 46 63 55 74 / 0 20 60 40 50 Albany 59 44 64 52 74 / 0 20 50 30 40 Valdosta 62 46 69 56 78 / 10 10 30 20 20 Cross City 63 50 75 58 81 / 10 10 30 20 10 Apalachicola 64 54 67 62 73 / 0 20 30 20 30 && .TAE Watches/Warnings/Advisories... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...DVD SHORT TERM...MCDERMOTT LONG TERM...MCDERMOTT AVIATION...DVD MARINE...MCDERMOTT FIRE WEATHER...GOULD HYDROLOGY...GOULD
AREA FORECAST DISCUSSION
NWS CARIBOU ME
715 AM EST THU JAN 1 2015 .SYNOPSIS... A WARM FRONT WILL LIFT ACROSS THE REGION TODAY. AN ARCTIC FRONT WILL SWEEP THROUGH THE REGION LATER TONIGHT INTO FRIDAY. HIGH PRESSURE WILL BUILD INTO THE REGION FROM CANADA FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... 715 AM UPDATE...ADJUSTED THE HRLY TEMPERATURES AND SKY CONDITIONS TO MATCH THE LATEST OBS.11Z SURFACE ANALYSIS SHOWED THE WARM FRONT LIFTING NORTH W/HINTS OF A WEAK LOW DEVELOPING THE FRONT ALONG THE HANCOCK-WASHINGTON COUNTY COAST. POPS WERE PUSHED FURTHER EAST TO ACCOUNT FOR SOME LIGHT SNOW THIS MORNING AS THE RADAR WAS SHOWING SOME LIGHT RETURNS. NO OTHER CHANGES ATTM. LATEST SURFACE ANALYSIS SHOWED WARM FRONT LIFTING N ACROSS THE PINE TREE STATE. SOME LIGHT PRECIP IN THE FORM OF SOME LIGHT SNOW ACROSS THE IMMEDIATE COAST W/MOST OF PRECIP OFFSHORE. FURTHER N, THE RADAR SHOWED SOME VERY LIGHT RETURNS IN THE FORM OF SOME FLURRIES. TEMPERATURES WERE SLOWLY RISING THIS MORNING AND WILL CONTINUE TO DO SO TODAY W/THE WARM FRONT PASSAGE. PERIODS OF LIGHT SNOW/SNOW SHOWERS EXPECTED ACROSS THE NORTH AND WEST AND RIGHT ALONG THE DOWNEAST COAST. THE NAM AND RAP GUIDANCE POINT TO SOME STEEPENING LAPSE RATES OF 7.0C/KM FROM 850-700MBS W/THE WARM FRONT. THE BEST CHANCE FOR ANY ACCUMULATING SNOW WILL BE ACROSS THE FAR W AND NW W/AN INCH POSSIBLE. TEMPERATURES ARE EXPECTED TO THE UPPER TEENS AND LOWER FOR THE NORTHERN 1/2 OF THE CWA AND MID/UPPER 20S CENTRAL TO THE DOWNEAST REGION. THINGS GET EVEN MORE INTERESTING THIS EVENING AND OVERNIGHT W/THE ARCTIC FRONT EXPECTED TO MOVE ACROSS THE REGION. BOTH THE NAM AND GFS SOUNDINGS SHOW DEEP MOISTURE THROUGH 700MBS W/ANOTHER ROUND OF STEEP LAPSE RATES AOA 7.0C/KM IN THE 850-700MB LAYER. DECENT SHEAR OF 30KTS IN THE 0-3KM LAYER. BTV SNOW SQUALL PARAMETER SHOWS A STRONG SIGNAL SUPPORTING THE POTENTIAL FOR SNOW SQUALLS WHICH COULD DUMP A QUICK INCH OF SNOW W/GUSTY WINDS AND VSBYS BLO 1/2SM. STAYED W/THE DAYCREW`S ASSESSMENT OF 60% POPS ACROSS THE NORTHERN 1/2 OF THE CWA INTO TONIGHT AS THE ARCTIC FRONT SLIDES ACROSS THE REGION. TEMPERATURES WILL DROP OFF, BUT NOT UNTIL AFTER 09Z. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... THE COLD FRONT WILL SWEEP EAST ON FRIDAY AS HIGH PRESSURE BEGINS TO BUILD IN FROM CENTRAL CANADA. WE COULD SEE A FEW MORNING SNOW SHOWERS OTHERWISE PARTLY TO MOSTLY CLOUDY SKIES CAN BE EXPECTED ACROSS THE REGION ON FRIDAY. HIGHS ON FRIDAY WILL RANGE FROM 10 TO 15 ABOVE NORTH AND MID 20S DOWN EAST. MAINLY CLEAR AND VERY COLD WEATHER CAN BE EXPECTED FOR FRIDAY NIGHT. LOWS WILL RANGE FROM 10 TO 15 BELOW ACROSS TEH NORTH AND ZERO TO 10 ABOVE DOWNEAST. MOSTLY SUNNY SKIES CAN BE EXPECTED ON SATURDAY BEFORE WE SEE INCREASING HIGH CLOUDS SATURADY AFTERNOON. HIGHS ON SATURDAY WILL RANGE FROM THE SINGLE DIGITS ABOVE ZERO NORTH AND MID TEENS TO NEAR 20S DOWN EAST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... CLOUDS INCREASE SATURDAY EVENING WITH SNOW DEVELOPING AFTER MIDNIGHT. THE LATEST GFS/ECMWF TRACK LOW PRESSURE OFF TO OUR NORTHWEST DURING SATURDAY NIGHT AND SUNDAY AS WEAK LOW PRESSURE DEVELOPS ALONG THE DOWN EAST COAST. APPEARS AS IF THE LOW TRACKING OFF TO OUR NORTHWEST WILL REMAIN THE PRIMARY LOW ALLOWING WARMER AIR TO CHANGE PRECIPITATION TO A MIX OR ALL RAIN ACROSS DOWNEAST AND CENTRAL AREAS DURING SUNDAY. AT THIS TIME LOOKS LIKE THIS SYSTEM WILL BE AN ADVISORY LEVEL EVENT. PRECIPITATION WILL START TO WIND DOWN SUNDAY NIGHT AS THE LOW MOVES AWAY FROM THE REGION. VERY COLD AIR WILL BEGIN TO POUR INTO THE REGION DURING MONDAY WITH HIGHS OCCURRING EARLY IN THE DAY. VERY COLD AND DRY WEATHER FOR MONDAY NIGHT AND TUEDSAY. A CLIPPER TYPE LOW MAY BRING SOME SNOW TO ESPECIALLY DOWN EAST AREAS TUESDAY NIGHT AND WEDNESDAY. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... NEAR TERM: VFR EXPECTED W/TEH EXCEPTION OF THE NORTHERN TERMINALS ESPECIALLY KCAR AND KFVE AS MVFR CONDITIONS ARE POSSIBLE LATER THIS AFTERNOON INTO TONIGHT IN SNOW SHOWERS/SQUALLS. SHORT TERM: IFR IN PRECIPITATION SATURDAY NIGHT THROUGH SUNDAY NIGHT. OTHERWISE VFR FRIDAY AND MONDAY. && .MARINE... NEAR TERM: THE SCA WILL STAY UP THROUGH TONIGHT W/WINDS INCREASING TO 20-25 KTS BY TONIGHT. THE OUTER ZONES COULD SEE GUSTS TO 30 KTS AS A LLVL JET OF 45 KTS MOVES OVER THE WATERS AHEAD OF THE APCHG ARCTIC FRONT. SEAS WILL RESPOND ACCORDINGLY BUILDING TO 6-8 FT BY TONIGHT. SHORT TERM:SMALL CRAFT ADVISORY LEVEL CONDITIONS ARE EXPECTED FRIDAY AND FRIDAY NIGHT. CONDITIONS SHOULD THEN DECREASE BELOW SMALL CRAFT ADVISORY LEVELS SATURDAY WITH CONDITIONS ONCE AGAIN INCREASING TO SCA LEVELS SATURDAY NIGHT AND SUNDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR ANZ050>052. && $$ NEAR TERM...HEWITT SHORT TERM...DUDA LONG TERM...DUDA AVIATION...HEWITT/DUDA MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
518 AM EST THU JAN 1 2015 .SYNOPSIS... A WARM FRONT WILL LIFT ACROSS THE REGION TODAY. AN ARCTIC FRONT WILL SWEEP THROUGH THE REGION LATER TONIGHT INTO FRIDAY. HIGH PRESSURE WILL BUILD INTO THE REGION FROM CANADA FRIDAY NIGHT INTO SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... LATEST SURFACE ANALYSIS SHOWED WARM FRONT LIFTING N ACROSS THE PINE TREE STATE. SOME LIGHT PRECIP IN THE FORM OF SOME LIGHT SNOW ACROSS THE IMMEDIATE COAST W/MOST OF PRECIP OFFSHORE. FURTHER N, THE RADAR SHOWED SOME VERY LIGHT RETURNS IN THE FORM OF SOME FLURRIES. TEMPERATURES WERE SLOWLY RISING THIS MORNING AND WILL CONTINUE TO DO SO TODAY W/THE WARM FRONT PASSAGE. PERIODS OF LIGHT SNOW/SNOW SHOWERS EXPECTED ACROSS THE NORTH AND WEST AND RIGHT ALONG THE DOWNEAST COAST. THE NAM AND RAP GUIDANCE POINT TO SOME STEEPENING LAPSE RATES OF 7.0C/KM FROM 850-700MBS W/THE WARM FRONT. THE BEST CHANCE FOR ANY ACCUMULATING SNOW WILL BE ACROSS THE FAR W AND NW W/AN INCH POSSIBLE. TEMPERATURES ARE EXPECTED TO THE UPPER TEENS AND LOWER FOR THE NORTHERN 1/2 OF THE CWA AND MID/UPPER 20S CENTRAL TO THE DOWNEAST REGION. THINGS GET EVEN MORE INTERESTING THIS EVENING AND OVERNIGHT W/THE ARCTIC FRONT EXPECTED TO MOVE ACROSS THE REGION. BOTH THE NAM AND GFS SOUNDINGS SHOW DEEP MOISTURE THROUGH 700MBS W/ANOTHER ROUND OF STEEP LAPSE RATES AOA 7.0C/KM IN THE 850-700MB LAYER. DECENT SHEAR OF 30KTS IN THE 0-3KM LAYER. BTV SNOW SQUALL PARAMETER SHOWS A STRONG SIGNAL SUPPORTING THE POTENTIAL FOR SNOW SQUALLS WHICH COULD DUMP A QUICK INCH OF SNOW W/GUSTY WINDS AND VSBYS BLO 1/2SM. STAYED W/THE DAYCREW`S ASSESSMENT OF 60% POPS ACROSS THE NORTHERN 1/2 OF THE CWA INTO TONIGHT AS THE ARCTIC FRONT SLIDES ACROSS THE REGION. TEMPERATURES WILL DROP OFF, BUT NOT UNTIL AFTER 09Z. && .SHORT TERM /FRIDAY THROUGH SATURDAY/... THE COLD FRONT WILL SWEEP EAST ON FRIDAY AS HIGH PRESSURE BEGINS TO BUILD IN FROM CENTRAL CANADA. WE COULD SEE A FEW MORNING SNOW SHOWERS OTHERWISE PARTLY TO MOSTLY CLOUDY SKIES CAN BE EXPECTED ACROSS THE REGION ON FRIDAY. HIGHS ON FRIDAY WILL RANGE FROM 10 TO 15 ABOVE NORTH AND MID 20S DOWN EAST. MAINLY CLEAR AND VERY COLD WEATHER CAN BE EXPECTED FOR FRIDAY NIGHT. LOWS WILL RANGE FROM 10 TO 15 BELOW ACROSS TEH NORTH AND ZERO TO 10 ABOVE DOWNEAST. MOSTLY SUNNY SKIES CAN BE EXPECTED ON SATURDAY BEFORE WE SEE INCREASING HIGH CLOUDS SATURADY AFTERNOON. HIGHS ON SATURDAY WILL RANGE FROM THE SINGLE DIGITS ABOVE ZERO NORTH AND MID TEENS TO NEAR 20S DOWN EAST. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... CLOUDS INCREASE SATURDAY EVENING WITH SNOW DEVELOPING AFTER MIDNIGHT. THE LATEST GFS/ECMWF TRACK LOW PRESSURE OFF TO OUR NORTHWEST DURING SATURDAY NIGHT AND SUNDAY AS WEAK LOW PRESSURE DEVELOPS ALONG THE DOWN EAST COAST. APPEARS AS IF THE LOW TRACKING OFF TO OUR NORTHWEST WILL REMAIN THE PRIMARY LOW ALLOWING WARMER AIR TO CHANGE PRECIPITATION TO A MIX OR ALL RAIN ACROSS DOWNEAST AND CENTRAL AREAS DURING SUNDAY. AT THIS TIME LOOKS LIKE THIS SYSTEM WILL BE AN ADVISORY LEVEL EVENT. PRECIPITATION WILL START TO WIND DOWN SUNDAY NIGHT AS THE LOW MOVES AWAY FROM THE REGION. VERY COLD AIR WILL BEGIN TO POUR INTO THE REGION DURING MONDAY WITH HIGHS OCCURRING EARLY IN THE DAY. VERY COLD AND DRY WEATHER FOR MONDAY NIGHT AND TUEDSAY. A CLIPPER TYPE LOW MAY BRING SOME SNOW TO ESPECIALLY DOWN EAST AREAS TUESDAY NIGHT AND WEDNESDAY. && .AVIATION /09Z THURSDAY THROUGH MONDAY/... NEAR TERM: VFR EXPECTED W/TEH EXCEPTION OF THE NORTHERN TERMINALS ESPECIALLY KCAR AND KFVE AS MVFR CONDITIONS ARE POSSIBLE LATER THIS AFTERNOON INTO TONIGHT IN SNOW SHOWERS/SQUALLS. SHORT TERM: IFR IN PRECIPITATION SATURDAY NIGHT THROUGH SUNDAY NIGHT. OTHERWISE VFR FRIDAY AND MONDAY. && .MARINE... NEAR TERM: THE SCA WILL STAY UP THROUGH TONIGHT W/WINDS INCREASING TO 20-25 KTS BY TONIGHT. THE OUTER ZONES COULD SEE GUSTS TO 30 KTS AS A LLVL JET OF 45 KTS MOVES OVER THE WATERS AHEAD OF THE APCHG ARCTIC FRONT. SEAS WILL RESPOND ACCORDINGLY BUILDING TO 6-8 FT BY TONIGHT. SHORT TERM:SMALL CRAFT ADVISORY LEVEL CONDITIONS ARE EXPECTED FRIDAY AND FRIDAY NIGHT. CONDITIONS SHOULD THEN DECREASE BELOW SMALL CRAFT ADVISORY LEVELS SATURDAY WITH CONDITIONS ONCE AGAIN INCREASING TO SCA LEVELS SATURDAY NIGHT AND SUNDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST FRIDAY FOR ANZ050>052. && $$ NEAR TERM...HEWITT SHORT TERM...DUDA LONG TERM...DUDA AVIATION...HEWITT/DUDA MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
931 AM CST THU JAN 1 2015 .UPDATE... SUBSTANTIAL ADJUSTMENTS NEEDED TO FORECAST TODAY...PRIMARILY TO INCREASE POPS ESPECIALLY OVER S/SW SECTIONS...AND TO LOWER TEMPS A BIT. && .SHORT TERM... MORNING RADAR AND ANALYSES SHOW EXPANDING AREA OF PRECIPITATION ACROSS MUCH OF LA/E TX/S AR/SW MS. THIS IS IN AREA OF INCREASING MOISTURE ADVECTION/ISENTROPIC ASCENT ABOVE REMNANT WEAKENING SFC HIGH PRESSURE ACROSS REGION. RADAR TRENDS AND LATEST HRRR/RAP MODELS SUGGEST THAT EARLIER GLOBAL MODELS WERE A BIT TOO FAR NORTH IN DEPICTION OF BEST RAINFALL POTENTIAL FOR TODAY...WITH BETTER MOISTURE ADVECTION LIKELY TO FOCUS BETTER QPF FARTHER TO THE S CLOSER TO THE I-20 CORRIDOR. BLEND OF LAST FEW HRRR RUNS SUGGEST AN AXIS OF 0.5 TO 1.5" OF QPF THROUGH EARLY THIS EVENING FROM THE LOWER ARKLAMISS DELTA BACK WSW INTO EC TX...WITH AMOUNTS OF AT LEAST .1" OVER MOST OF OUR SERVICE AREA. HENCE HAVE ADJUSTED POPS TO MAINTAIN HIGH POPS OVER DELTA BUT EXPAND CATEGORICAL POPS TO ENCOMPASS MOST OF THE WESTERN 2/3 OF OUR AREA. TAPERED POPS TO THE E WHERE BETTER MOISTURE ADVECTION WILL BE SLOWER TO ARRIVE AND HENCE BETTER CHANCES FOR RAIN. HAVE HAD A COUPLE OF REPORTS OF SLEET IN WESTERN AREAS THIS MORNING...AND COLD...DRY SUBCLOUD LAYER DEPICTED IN SOUNDINGS THIS MORNING SUGGEST THIS REMAINS A POSSIBILITY NEXT FEW HOURS ESPECIALLY NORTHERN HALF OF AREA. HAVE KEPT THIS IN GRIDS...BUT AS MENTIONED IN PREVIOUS AFD SHOULD NOT BE ANY IMPACT WITH TEMPS ABOVE FREEZING. LIGHTNING DATA HAS SHOWN SPORADIC STRIKES WITH ACTIVITY SHIFTING ACROSS E TX THIS MORNING...AND MODELS SHOW A COUPLE OF HUNDRED OF JOULES OF ELEVATED CAPE WORKING INTO SW SECTIONS OF OUR AREA THIS AFTERNOON. THIS IN COMBO WITH HRRR HAVING SOME CONVECTIVE LOOKING ELEMENTS IN ITS REFLECTIVITY FORECASTS HAVE RESULTED IN AN ADDITION OF SLGT CHC TSRA FOR SW AREAS THIS AFTERNOON WHICH ALSO AGREES WITH LATEST SPC DAY 1 OUTLOOK. GIVEN ARRIVAL OF CLOUDS/RAIN AND CONTINUED STAGNANT REMNANT COLD...DRY SURFACE HIGH OVER AREA...THINK TEMPS WILL REALLY STRUGGLE MOST AREAS TODAY. HENCE HAVE KNOCKED A COUPLE OF DEGS OFF MAXES AND WENT WITH HRRR HOURLY TEMPS. A BIT OF MORNING SUN IN FAR E/SE SECTIONS COULD ALLOW TEMPS THERE TO REACH FORECAST MAXES AND HRRR SUPPORTS THIS AS WELL...SO PRETTY MUCH LEFT MAXES IN THOSE AREAS ALONE. /AEG/ && .AVIATION... CIGS CONTINUE TO BE MAINLY VFR EVEN WITH LIGHT PRECIPITATION SPREADING EASTWARD ACROSS THE MS RIVER...INCLUDING SOME INSIGNIFICANT AMOUNTS OF LIGHT SLEET AT THE ONSET. BUT CONDITIONS QUICKLY WORSEN JUST WEST OF THE FORECAST AREA WITH WIDESPREAD MVFR/IFR CIGS AND VSBYS ASSOCIATED WITH RA/TSRA OVER WRN LA. EXPECT THIS HEAVIER RAINFALL TO CONTINUE TO DEVELOP EAST AND AFFECT THE GLH/GWO/JAN/HKS AREA INITIALLY THIS AFTERNOON...THEN ALL TAF SITES AS WE GO THROUGH TONIGHT. SOME ISOLATED TSRA WILL BE POSSIBLE PARTICULARLY AT GLH/JAN/HKS/HBG. FRIDAY WILL BE A POOR AVIATION WEATHER DAY WITH WIDESPREAD RA/TSRA PRODUCING IFR CONDITIONS OVER THE ENTIRE AREA. /EC/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 46 43 52 52 / 91 86 85 67 MERIDIAN 54 44 52 52 / 63 75 86 66 VICKSBURG 44 41 50 50 / 96 91 87 75 HATTIESBURG 56 48 60 60 / 58 64 71 50 NATCHEZ 44 43 56 55 / 92 86 75 71 GREENVILLE 45 38 45 44 / 95 95 93 82 GREENWOOD 47 39 47 47 / 90 91 91 74 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ AEG/EC
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
504 AM CST THU JAN 1 2015 .DISCUSSION... HAPPY NEW YEAR FROM ALL OF US AT NWS JACKSON! SHORT TERM (TODAY THROUGH FRIDAY NIGHT)... WHILE COOL/RELATIVELY DRY NORTHERLY/EASTERLY FLOW WILL CONTINUE AT THE SURFACE...BIG CHANGES ARE AFOOT ABOUT 2000 FEET UP. FLOW IN THE LOWER LEVELS OF THE ATMOSPHERE WILL SHIFT AROUND TO THE SOUTHWEST... WITH STRONG ISENTROPIC UPGLIDE COMMENCING OVER THE REGION BRINGING INCREASING PRECIP CHANCES BY THIS AFTERNOON. LOOKING EVEN HIGHER IN THE ATMOSPHERE...AN UPPER LOW WAS LOCATED NEAR THE FOUR CORNERS REGION WITH A SPLIT UPPER JET OVER THE WEST PHASING TOGETHER OVER THE MIDWEST/MID ATLANTIC. MID AND HIGH CLOUDS HAVE ALREADY BEEN ON THE INCREASE ACROSS MUCH OF THE REGION OVERNIGHT...WHICH HAS LIMITED RADIATIONAL COOLING IN MANY AREAS. AS MORE SUBSTANTIAL ATMOSPHERIC MOISTENING OCCURS THROUGH THE DAY...THE CLOUD DECK WILL GRADUALLY LOWER AND LIGHT PRECIP WILL BEGIN TO REACH THE SURFACE. REGIONAL RADAR SHOWED LIGHT PRECIP REACHING THE ARKLATEX INTO NW LOUISIANA. LATEST HRRR RUNS SUGGEST SOME OF THIS ACTIVITY WILL MOVE INTO OUR NE LOUISIANA PARISHES SHORTLY AFTER DAYBREAK... SLOWLY SPREADING EASTWARD THROUGH THE MORNING. DUE TO SUBSTANTIALLY DRY AIR BELOW AROUND 800 MB...IT MAY TAKE A WHILE FOR PRECIP TO REACH THE GROUND...SO WE MAY SEE SEVERAL ECHOES ON RADAR WITH ONLY SPRINKLES INITIALLY. THIS DRY AIR MAY ALSO LEAD TO SOME LIGHT SLEET AT THE ONSET OF PRECIPITATION OVER THE DELTA AS WETBULBING OCCURS IN THE DRY LAYER. BUFR SOUNDINGS SUGGEST THIS WILL BE POSSIBLE UNTIL AROUND OR SHORTLY AFTER NOON. MAINTAINED A MENTION OF SLIGHT CHANCE OF SLEET IN THE FORECAST...BUT TO BE CLEAR...NO MEASURABLE SLEET AND NO IMPACTS ARE EXPECTED AS SURFACE TEMPS WILL BE ABOVE FREEZING DURING THIS TIME PERIOD AND PRECIP WILL BE RATHER LIGHT. MORE SUBSTANTIAL RAIN CHANCES WILL COME OVER THE NORTHWEST HALF OF THE CWA THIS AFTERNOON INTO TONIGHT ONCE LOW LEVEL DRY AIR IS NO LONGER AN ISSUE. THE CLOSED UPPER LOW WILL BECOME EMBEDDED IN UPPER LEVEL FLOW AS A TROUGH MOVING INTO THE SOUTHERN PLAINS ON FRIDAY. THIS WILL BRING MORE FAVORABLE UPPER DIVERGENCE OVER THE AREA... ESPECIALLY FARTHER NORTH IN THE CWA CLOSER TO THE UPPER JET STREAK...WITH CONTINUED ISENTROPIC ASCENT IN THE LOWER LEVELS. THUS LIKELY TO CATEGORICAL POPS WILL BE MAINTAINED ACROSS MOST OF THE CWA THROUGH FRIDAY NIGHT. THOUGH THE ATMOSPHERE WILL REMAIN STABLE AT THE SURFACE THROUGH MUCH OF THIS TIME...THERE WILL BE ELEVATED INSTABILITY AND CHANCE/SLIGHT CHANCE THUNDERSTORMS WERE MAINTAINED IN THE FORECAST. THE EASTWARD ADVANCE OF THE UPPER TROUGH WILL ALSO PROMPT SURFACE CYCLOGENESIS ALONG THE NW GULF COAST. THIS LOW WILL TRACK NORTHWARD FRIDAY NIGHT...FINALLY BRINGING RETURN FLOW AT THE SURFACE OVERNIGHT. SOME SURFACE BASED CONVECTION WILL BE POSSIBLE ACROSS THE SOUTH PART OF THE AREA OVERNIGHT AS DEWPOINTS RISE INTO THE MID 60S WITH SBCAPES POTENTIALLY RISING INTO THE 500-1000 J/KG RANGE. TEMPERATURES THROUGH THE SHORT TERM WILL PRIMARILY BE DRIVEN BY THE PRESENCE OF CLOUDS AND PRECIP...AND WAA ON FRIDAY NIGHT. TRENDED CLOSE TO RAW TEMP GUIDANCE THROUGHOUT THE PERIOD. /DL/ LONG TERM (SATURDAY THROUGH THURSDAY)L...ACTIVE WEATHER WILL CONTINUE INTO THE EXTENDED...WHERE THE PRIMARY FOCUS WILL BE ON HEAVY RAIN AND STORM POTENTIAL. ON SATURDAY A MID TO UPPER LEVEL CLOSED LOW WILL BE MOVING THROUGH THE PLAINS AND WILL EJECT AS A NEGATIVE TILTED SHORTWAVE TOWARD THE THE OHIO VALLEY. WE WILL BE UNDER THE RIGHT REAR QUAD OF AN MID TO UPPER LEVEL JET. ALSO LOWLEVEL JET WINDS(850-925 MB) WILL BE AROUND 35 TO 55 KNOTS...FROM THE SOUTH. THIS WILL SPELL GUSTY SOUTH WINDS ACROSS THE REGION WITH GUSTS 25-28 KNOTS. MEANWHILE LARGE SCALE MOISTURE TRANSPORT AND ASCENT WILL BE IN PROGRESS AS THE WARM SECTOR SURGES 60S DEWPOINTS INTO MOST OF THE REGION. THE QUESTION IS HOW FAR NORTH WILL WARM MARINE LAYER (MID TO UPPER 60S DEWPOINTS) TRAVEL. A COLD FRONT WILL MOVE ACROSS THE REGION DURING THE DAY WITH A SURFACE LOW MOVING NORTHEAST AND DEEPENING. CHECKING 00Z AND 12Z MODEL RUNS WHICH WERE SIMILAR WITH THE TRACK OF THE SURFACE LOW GENERALLY WEST OF THE MS RIVER...THUS BRINGING BETTER LOW LEVEL INSTABILITY ACROSS MOST THE REGION. MODEL SOUNDINGS SHOW GOOD SHEAR ALONG WITH CURVED HODOGRAPHS FOR SOME SEVERE POTENTIAL. THE GFS TRIES TO BRING IN 65 PLUS DEWPOINTS NEAR THE I-20 CORRIDOR WITH NEAR 70 DEWPOINTS NEAR OUR SOUTHEAST BORDER. THIS WILL BRING SOME CAPES IN EXCESS OF 1500 J/KG. THE SHEAR VECTORS WILL BE GENERALLY PARALLEL TO THE FRONT FOR SOME POSSIBLE QLCS COMPLEXES ALONG WITH HELICITY > 300. HEIGHTS ACROSS THE SOUTHEAST THOUGH ARE A LITTLE HIGH FOR THIS TIME OF THE YEAR. SPC SREF...CIPS AND NAM MODELS POINT THE GREATEST SEVERE RISK ALONG THE NATCHEZ TRACE CORRIDOR...WHERE THE HEIGHTS ARE A LITTLE MORE CONDUCIVE. IF THIS TREND CONTINUES MAY CONSIDER PUTTING THAT AREA IN AN ELEVATED RISK IN FUTURE MODEL RUNS. SO WILL KEEP THE LIMITED RISK FOR NOW. THE COLD FRONT WILL EXIT THE REGION DURING THE EVENING THUS ENDING THE SEVERE RISK. LOOKING AT THE HEAVY RAIN RISK. PWATS WILL INCREASE TO AROUND 1.7 INCHES WHICH IS THE HIGHER AVERAGE PERCENTILE FOR THIS TIME OF YEAR...WHICH SPELLS EFFICIENT RAINS. MODELS AND HPC ARE GENERALLY GOING FOR 1-2 INCHES WITH LOCALLY INCH AMOUNTS POSSIBLE ALONG AND AHEAD OF THE COLD FRONT. THIS WILL ADD TO OUR RECENT RAINS FOR SATURATED SOIL CONDITIONS. SO WILL KEEP THE LIMITED RISK FOR FLOODING FOR FRIDAY INTO SATURDAY. UNLESS THE MODELS SIGNAL HIGHER RAINFALL AMOUNTS IN FUTURE MODEL RUNS...NO FLOOD WATCH WILL BE CONSIDERED AT THIS TIME. THE RAINS WILL EXIT THE REGION ON SUNDAY MORNING. HIGH PRESSURE WILL SETTLE ACROSS THE REGION ON MONDAY. SO DRY AND COOL CONDITIONS WILL PREVAIL FOR SUNDAY THROUGH WEDNESDAY. ANOTHER SURGE OF COOL AIR WILL PUSH INTO THE REGION FOR TUESDAY INTO WEDNESDAY. WITH THIS AIRMASS IT LOOKS LIKE THE BEST PART OF THIS AIRMASS WILL MISS THE REGION TO THE NORTH. ON THURSDAY SHORTWAVE RIDGING WILL BUILD IN FROM THE WEST AS LOW LEVEL RETURN FLOW COMES IN FOR SOME SHOWERS IN THE SOUTHWEST BY EARLY FRIDAY./17/ && .AVIATION...VFR CONDITIONS WILL CONTINUE THROUGH AT LEAST EARLY AFTERNOON AT MOST TERMINALS...BUT THE MID CLOUD DECK WILL GRADUALLY LOWER THROUGH THE DAY...LIKELY REACHING MVFR CATEGORY TONIGHT IN ALL AREAS EXCEPT AROUND MEI AND HBG. LIGHT RAIN WILL SPREAD EASTWARD INTO THE REGION THIS MORNING...BECOMING MODERATE LATER ON TONIGHT. THIS MAY BRING VISIBILITY REDUCTIONS TO MVFR ESPECIALLY AT NORTHWEST TERMINALS WHERE MORE SUBSTANTIAL RAINFALL IS EXPECTED THROUGH THE TAF PERIOD. CEILING AND OCCASIONAL VISIBILITY REDUCTIONS WILL LIKELY PERSIST THROUGH THE WEEKEND. THERE IS A SMALL CHANCE OF LIGHT SLEET AT GWO AND GLH THIS MORNING...BUT NO ISSUES ARE EXPECTED TO RESULT FROM THIS. /DL/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 47 43 52 52 / 34 86 85 67 MERIDIAN 52 44 52 52 / 17 75 86 66 VICKSBURG 43 41 50 50 / 61 91 87 75 HATTIESBURG 57 48 60 60 / 21 64 71 50 NATCHEZ 45 43 56 55 / 42 86 75 71 GREENVILLE 40 38 45 44 / 93 95 93 82 GREENWOOD 44 39 47 47 / 91 91 91 74 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ DL/17
AREA FORECAST DISCUSSION
NWS JACKSON MS
418 AM CST THU JAN 1 2015 .DISCUSSION... HAPPY NEW YEAR FROM ALL OF US AT NWS JACKSON! SHORT TERM (TODAY THROUGH FRIDAY NIGHT)... WHILE COOL/RELATIVELY DRY NORTHERLY/EASTERLY FLOW WILL CONTINUE AT THE SURFACE...BIG CHANGES ARE AFOOT ABOUT 2000 FEET UP. FLOW IN THE LOWER LEVELS OF THE ATMOSPHERE WILL SHIFT AROUND TO THE SOUTHWEST... WITH STRONG ISENTROPIC UPGLIDE COMMENCING OVER THE REGION BRINGING INCREASING PRECIP CHANCES BY THIS AFTERNOON. LOOKING EVEN HIGHER IN THE ATMOSPHERE...AN UPPER LOW WAS LOCATED NEAR THE FOUR CORNERS REGION WITH A SPLIT UPPER JET OVER THE WEST PHASING TOGETHER OVER THE MIDWEST/MID ATLANTIC. MID AND HIGH CLOUDS HAVE ALREADY BEEN ON THE INCREASE ACROSS MUCH OF THE REGION OVERNIGHT...WHICH HAS LIMITED RADIATIONAL COOLING IN MANY AREAS. AS MORE SUBSTANTIAL ATMOSPHERIC MOISTENING OCCURS THROUGH THE DAY...THE CLOUD DECK WILL GRADUALLY LOWER AND LIGHT PRECIP WILL BEGIN TO REACH THE SURFACE. REGIONAL RADAR SHOWED LIGHT PRECIP REACHING THE ARKLATEX INTO NW LOUISIANA. LATEST HRRR RUNS SUGGEST SOME OF THIS ACTIVITY WILL MOVE INTO OUR NE LOUISIANA PARISHES SHORTLY AFTER DAYBREAK... SLOWLY SPREADING EASTWARD THROUGH THE MORNING. DUE TO SUBSTANTIALLY DRY AIR BELOW AROUND 800 MB...IT MAY TAKE A WHILE FOR PRECIP TO REACH THE GROUND...SO WE MAY SEE SEVERAL ECHOES ON RADAR WITH ONLY SPRINKLES INITIALLY. THIS DRY AIR MAY ALSO LEAD TO SOME LIGHT SLEET AT THE ONSET OF PRECIPITATION OVER THE DELTA AS WETBULBING OCCURS IN THE DRY LAYER. BUFR SOUNDINGS SUGGEST THIS WILL BE POSSIBLE UNTIL AROUND OR SHORTLY AFTER NOON. MAINTAINED A MENTION OF SLIGHT CHANCE OF SLEET IN THE FORECAST...BUT TO BE CLEAR...NO MEASURABLE SLEET AND NO IMPACTS ARE EXPECTED AS SURFACE TEMPS WILL BE ABOVE FREEZING DURING THIS TIME PERIOD AND PRECIP WILL BE RATHER LIGHT. MORE SUBSTANTIAL RAIN CHANCES WILL COME OVER THE NORTHWEST HALF OF THE CWA THIS AFTERNOON INTO TONIGHT ONCE LOW LEVEL DRY AIR IS NO LONGER AN ISSUE. THE CLOSED UPPER LOW WILL BECOME EMBEDDED IN UPPER LEVEL FLOW AS A TROUGH MOVING INTO THE SOUTHERN PLAINS ON FRIDAY. THIS WILL BRING MORE FAVORABLE UPPER DIVERGENCE OVER THE AREA... ESPECIALLY FARTHER NORTH IN THE CWA CLOSER TO THE UPPER JET STREAK...WITH CONTINUED ISENTROPIC ASCENT IN THE LOWER LEVELS. THUS LIKELY TO CATEGORICAL POPS WILL BE MAINTAINED ACROSS MOST OF THE CWA THROUGH FRIDAY NIGHT. THOUGH THE ATMOSPHERE WILL REMAIN STABLE AT THE SURFACE THROUGH MUCH OF THIS TIME...THERE WILL BE ELEVATED INSTABILITY AND CHANCE/SLIGHT CHANCE THUNDERSTORMS WERE MAINTAINED IN THE FORECAST. THE EASTWARD ADVANCE OF THE UPPER TROUGH WILL ALSO PROMPT SURFACE CYCLOGENESIS ALONG THE NW GULF COAST. THIS LOW WILL TRACK NORTHWARD FRIDAY NIGHT...FINALLY BRINGING RETURN FLOW AT THE SURFACE OVERNIGHT. SOME SURFACE BASED CONVECTION WILL BE POSSIBLE ACROSS THE SOUTH PART OF THE AREA OVERNIGHT AS DEWPOINTS RISE INTO THE MID 60S WITH SBCAPES POTENTIALLY RISING INTO THE 500-1000 J/KG RANGE. TEMPERATURES THROUGH THE SHORT TERM WILL PRIMARILY BE DRIVEN BY THE PRESENCE OF CLOUDS AND PRECIP...AND WAA ON FRIDAY NIGHT. TRENDED CLOSE TO RAW TEMP GUIDANCE THROUGHOUT THE PERIOD. /DL/ LONG TERM (SATURDAY THROUGH THURSDAY)L...ACTIVE WEATHER WILL CONTINUE INTO THE EXTENDED...WHERE THE PRIMARY FOCUS WILL BE ON HEAVY RAIN AND STORM POTENTIAL. ON SATURDAY A MID TO UPPER LEVEL CLOSED LOW WILL BE MOVING THROUGH THE PLAINS AND WILL EJECT AS A NEGATIVE TILTED SHORTWAVE TOWARD THE THE OHIO VALLEY. WE WILL BE UNDER THE RIGHT REAR QUAD OF AN MID TO UPPER LEVEL JET. ALSO LOWLEVEL JET WINDS(850-925 MB) WILL BE AROUND 35 TO 55 KNOTS...FROM THE SOUTH. THIS WILL SPELL GUSTY SOUTH WINDS ACROSS THE REGION WITH GUSTS 25-28 KNOTS. MEANWHILE LARGE SCALE MOISTURE TRANSPORT AND ASCENT WILL BE IN PROGRESS AS THE WARM SECTOR SURGES 60S DEWPOINTS INTO MOST OF THE REGION. THE QUESTION IS HOW FAR NORTH WILL WARM MARINE LAYER (MID TO UPPER 60S DEWPOINTS) TRAVEL. A COLD FRONT WILL MOVE ACROSS THE REGION DURING THE DAY WITH A SURFACE LOW MOVING NORTHEAST AND DEEPENING. CHECKING 00Z AND 12Z MODEL RUNS WHICH WERE SIMILAR WITH THE TRACK OF THE SURFACE LOW GENERALLY WEST OF THE MS RIVER...THUS BRINGING BETTER LOW LEVEL INSTABILITY ACROSS MOST THE REGION. MODEL SOUNDINGS SHOW GOOD SHEAR ALONG WITH CURVED HODOGRAPHS FOR SOME SEVERE POTENTIAL. THE GFS TRIES TO BRING IN 65 PLUS DEWPOINTS NEAR THE I-20 CORRIDOR WITH NEAR 70 DEWPOINTS NEAR OUR SOUTHEAST BORDER. THIS WILL BRING SOME CAPES IN EXCESS OF 1500 J/KG. THE SHEAR VECTORS WILL BE GENERALLY PARALLEL TO THE FRONT FOR SOME POSSIBLE QLCS COMPLEXES ALONG WITH HELICITY > 300. HEIGHTS ACROSS THE SOUTHEAST THOUGH ARE A LITTLE HIGH FOR THIS TIME OF THE YEAR. SPC SREF...CIPS AND NAM MODELS POINT THE GREATEST SEVERE RISK ALONG THE NATCHEZ TRACE CORRIDOR...WHERE THE HEIGHTS ARE A LITTLE MORE CONDUCIVE. IF THIS TREND CONTINUES MAY CONSIDER PUTTING THAT AREA IN AN ELEVATED RISK IN FUTURE MODEL RUNS. SO WILL KEEP THE LIMITED RISK FOR NOW. THE COLD FRONT WILL EXIT THE REGION DURING THE EVENING THUS ENDING THE SEVERE RISK. LOOKING AT THE HEAVY RAIN RISK. PWATS WILL INCREASE TO AROUND 1.7 INCHES WHICH IS THE HIGHER AVERAGE PERCENTILE FOR THIS TIME OF YEAR...WHICH SPELLS EFFICIENT RAINS. MODELS AND HPC ARE GENERALLY GOING FOR 1-2 INCHES WITH LOCALLY INCH AMOUNTS POSSIBLE ALONG AND AHEAD OF THE COLD FRONT. THIS WILL ADD TO OUR RECENT RAINS FOR SATURATED SOIL CONDITIONS. SO WILL KEEP THE LIMITED RISK FOR FLOODING FOR FRIDAY INTO SATURDAY. UNLESS THE MODELS SIGNAL HIGHER RAINFALL AMOUNTS IN FUTURE MODEL RUNS...NO FLOOD WATCH WILL BE CONSIDERED AT THIS TIME. THE RAINS WILL EXIT THE REGION ON SUNDAY MORNING. HIGH PRESSURE WILL SETTLE ACROSS THE REGION ON MONDAY. SO DRY AND COOL CONDITIONS WILL PREVAIL FOR SUNDAY THROUGH WEDNESDAY. ANOTHER SURGE OF COOL AIR WILL PUSH INTO THE REGION FOR TUESDAY INTO WEDNESDAY. WITH THIS AIRMASS IT LOOKS LIKE THE BEST PART OF THIS AIRMASS WILL MISS THE REGION TO THE NORTH. ON THURSDAY SHORTWAVE RIDGING WILL BUILD IN FROM THE WEST AS LOW LEVEL RETURN FLOW COMES IN FOR SOME SHOWERS IN THE SOUTHWEST BY EARLY FRIDAY./17/ && .AVIATION...VFR CONDITIONS WILL CONTINUE THROUGH AT LEAST EARLY AFTERNOON AT MOST TERMINALS...BUT THE MID CLOUD DECK WILL GRADUALLY LOWER THROUGH THE DAY...LIKELY REACHING MVFR CATEGORY TONIGHT IN ALL AREAS EXCEPT AROUND MEI AND HBG. LIGHT RAIN WILL SPREAD EASTWARD INTO THE REGION THIS MORNING...BECOMING MODERATE LATER ON TONIGHT. THIS MAY BRING VISIBILITY REDUCTIONS TO MVFR ESPECIALLY AT NORTHWEST TERMINALS WHERE MORE SUBSTANTIAL RAINFALL IS EXPECTED THROUGH THE TAF PERIOD. CEILING AND OCCASIONAL VISIBILITY REDUCTIONS WILL LIKELY PERSIST THROUGH THE WEEKEND. /DL/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 47 43 52 52 / 34 86 85 67 MERIDIAN 52 44 52 52 / 17 75 86 66 VICKSBURG 43 41 50 50 / 61 91 87 75 HATTIESBURG 57 48 60 60 / 21 64 71 50 NATCHEZ 45 43 56 55 / 42 86 75 71 GREENVILLE 40 38 45 44 / 93 95 93 82 GREENWOOD 44 39 47 47 / 91 91 91 74 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ DL/17
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
935 AM EST THU JAN 1 2015 .SYNOPSIS... HIGH PRESSURE ACROSS THE SOUTHEASTERN U.S. WILL MOVE OFFSHORE FRIDAY. RAIN CHANCES WILL INCREASE FRIDAY...WITH PERIODS OF RAIN EXPECTED FRIDAY NIGHT AND SATURDAY AS A WARM FRONT APPROACHES. A STRONG COLD FRONT MAY BRING A FEW THUNDERSTORMS SUNDAY AFTERNOON AND NIGHT. CLEAR AND COLD CONDITIONS WILL OVERSPREAD THE CAROLINAS MONDAY THROUGH WEDNESDAY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM THURSDAY...VERY FEW CHANGES WERE NEEDED TO THE FORECAST. SKIES ARE CLEAR WITH SATELLITE IMAGERY INDICATING CIRRUS NOW APPROACHING THE SOUTHERN APPALACHIANS WILL BEGIN TO REACH THE COAST THIS AFTERNOON. 12Z SOUNDINGS FROM MHX AND GSO LOOKED MUCH LIKE THE 06Z MODELS INDICATED. BASED ON RECENT HRRR AND RUC MODELS I HAVE INCREASED ONSHORE WINDS BY A FEW MPH THIS AFTERNOON NEAR THE BEACHES WITH A WEAK SEABREEZE CIRCULATION. THIS ONSHORE WIND WILL ALSO UNFORTUNATELY DRAG SOME PRETTY CHILLY AIR BACK IN FROM THE OCEAN DURING THE MID-AFTERNOON HOURS. INLAND HIGHS SHOULD RANGE FROM 54-57...WITH THE BEACHES RUNNING A FEW DEGREES COOLER. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM THURSDAY...FOR THE MEDIUM AND LONG RANGE PACKAGE WILL FAVOR THE GFS/ECMWF SOLUTION FOR THE PERIOD. H5 CUT OFF LOW ACROSS THE SW RESULTS IN SPLIT FLOW ACROSS THE CONUS WITH RIDGING ACROSS THE GULF COAST AND SE THROUGH THE PERIOD. EXPECT CLOUDS TO STREAM INTO THE AREA AND THICKEN ON FRIDAY WITH PRECIPITATION CHANCES INCREASING AS GULF MOISTURE BECOMES AVAILABLE. BELIEVE THE FIRST HALF OF THE DAY SHOULD REMAIN DRY WITH CHANCE POPS DURING THE LATER HALF OF FRIDAY. MAIN BULK OF PRECIPITATION STAYS TO OUR WEST AS H5 LOW AND SURFACE LOW TRACK TO THE NE . H8 LOW LEVEL JET INCREASE TO 30-35 KNOTS ACROSS THE REGION INCREASING LOW LEVEL INSTABILITY AS EXIT REGION OF JET MOVES ACROSS THE CWA LATE SATURDAY. WITH H5 SW FLOW WILL LOOK FOR MODERATING TEMPERATURES THROUGH THE PERIOD. MOST OF THE PRECIPITATION WILL BE ON THE LIGHT SIDE FRIDAY INTO SATURDAY WITH BREAKS THROUGHOUT THE PERIOD. WILL STAY CLOSE TO GUIDANCE TEMPS FOR THE PERIOD. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 300 AM THURSDAY...EXPECT SUNDAY TO BE THE MORE ACTIVE DAY OF THE WEEKEND WITH THE SPLIT FLOW PATTERN ACROSS THE US PHASING IN ACROSS THE EASTERN HALF OF THE COUNTRY DURING THIS PERIOD AS H5 LOW AND SURFACE LOW MOVE INTO THE GREAT LAKES WITH DEVELOPING TROUGH ACROSS THE CENTRAL U.S. H5 SW FLOW ACROSS THE SE WITH ABOVE NORMAL TEMPERATURES EXPECTED ON SUNDAY AND THE GREATER RISK OF RAIN AND POSSIBLE THUNDERSTORMS AHEAD OF ADVANCING COLD FRONT MOVING INTO THE CAROLINAS. MODELS PEG THE FRONT ACROSS THE CWA DURING LATE AFTERNOON INTO THE EARLY EVENING WITH BEST DYNAMICS AT THIS TIME TO SUPPORT SOME ELEVATED CONVECTION AIDED BY DEPARTED H8 JET STREAK ACROSS THE REGION. WILL MAKE MENTION OF SLIGHT CHANCE OF TSTM IN THE GRIDS FOR THE AFTERNOON/EVENING PERIOD. AS THE FRONT EXITS THE COAST LATE SUNDAY AND H5 FLOW DAMPENS OUT BECOMING MORE ZONAL FOR NEXT WEEK EXPECT SEASONABLE TO SLIGHTLY ABOVE CLIMO TEMPS FOR NEXT WEEK FOR THE HIGHS AND CLEAR BUT COOLER OVERNIGHT LOWS BELOW SLIGHTLY BELOW CLIMO AS CANADIAN HIGH PRESSURE BUILD IN FORM THE WEST BUT STAYS TO OUR NORTH. GFS SEEMS TO WANT TO DEVELOP A SURFACE LOW OFF THE SE COAST LATE IN THE PERIOD BUT ITS FURTHER EAST THEN THE 31/00Z RUN OF LAST NIGHT AND WEAKER. THE ECMWF HAS NOT HAD THIS FEATURE DURING THE PAST FEW RUNS SO WITH HE GFS TRENDING WEAKER AND FURTHER EAST IT WILL NOT IMPACT THE REGION TUESDAY INTO WEDNESDAY. H5 FLOW BECOMES MORE NW TOWARDS THE END OF THE PERIOD AND WE START TO SEE COOLER TEMPS ARRIVE BY THURSDAY INTO FRIDAY. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... AS OF 12Z...CRE AND FLO WILL HAVE TO DEAL WITH FOG FOR THE FIRST HOUR OR SO...OTHERWISE VFR CONDITIONS ARE EXPECTED THROUGH THE END OF THE FORECAST PERIOD. HIGH PRESSURE WILL SHIFT OFFSHORE THIS AFTERNOON...ALLOWING RETURN FLOW WITH INCREASING MID AND UPPER LEVEL MOISTURE LATE THIS AFTERNOON THROUGH THE OVERNIGHT HOURS. SHOULD SEE A MID CLOUD CEILING SOMETIME AFTER MIDNIGHT. THE INSULATING CLOUD LAYER SHOULD KEEP FOG AT BAY. LIGHT SOUTHERLY FLOW TODAY WITH LIGHT TO NEAR CALM WINDS TONIGHT. EXTENDED OUTLOOK...VFR INTO FRI. CHANCE OF RAIN AND MVFR/TEMPO IFR CONDITIONS FRI NIGHT THROUGH SUN. BECOMING VFR LATE SUN. VFR MON. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM THURSDAY...VERY FEW CHANGES WERE NEEDED TO THE FORECAST. BASED ON LATEST HRRR AND RUC MODELS I HAVE BUMPED UP WIND SPEEDS BETWEEN 1-5 PM BY A FEW KNOTS NEAR THE BEACHES WITH A WEAK SEABREEZE CIRCULATION. WIND SPEEDS STILL WILL REMAIN LESS THAN 10 KT. SEAS ARE BARELY 1-2 FEET AND SHOULD CHANGE LITTLE THROUGH THE DAY. E THE RULE TONIGHT. SEAS WILL BE 2 FT OR LESS THROUGH THE PERIOD. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM THURSDAY...WEAK BUBBLE HIGH ACROSS THE COASTAL WATERS DURING FRIDAY WILL RESULT IN RELATIVELY LIGHT WINDS AND SEAS LESS THAN 10 KT WITH SEAS 1-2 FEET NEAR SHORE AND 2-3 OFFSHORE. SATURDAY THE WINDS INCREASE FROM THE EAST AS COASTAL TROUGH OFFSHORE INTERACTS WITH THE FRONT TO UR WEST IN TIGHTENING THE PRESSURE GRADIENT ACROSS THE WATERS. BY MID DAY SATURDAY EAST WINDS OF 10-15 KTS NEAR SHORE AND 15-20 KTS OFFSHORE WILL START TO BUILD SEAS TO 2-4 NEAR SHORE AND 3-5 FEET OFFSHORE APPROACHING 6 FEET IN THE OUTER MARINE ZONES BY LATE SATURDAY. LONG TERM /SUNDAY THROUGH MONDAY/... AS OF 300 AM THURSDAY...SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE SUNDAY AND MAYBE MONDAY AS FRONT APPROACHES THE COASTAL WATERS AND WINDS VEER TO THE SW AND INCREASE TO 15-20 KTS NEAR SHORE AND 20 TO 25 KTS OFFSHORE WITH BUILDING SEAS. WITH H8 JET STREAK EXITING THE AREA AND THREAT OF ISOLATED THUNDERSTORMS SEAS SHOULD REACT AND BUILD QUICKLY ON SUNDAY AND BE CHOPPY. FRONT PASSES ACROSS THE COASTAL WATERS LATE SUNDAY NIGHT EARLY MONDAY AND WINDS BECOME NORTHWEST STILL RATHER STRONG AT 15-20 KTS WILL KEEP SEAS UP FOR THE EARLY PART OF MONDAY BEFORE SUBSIDING A BIT BY AFTERNOON BUT NOT BY MUCH. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RJD/TRA SHORT TERM...MAC LONG TERM...MAC AVIATION...43
AREA FORECAST DISCUSSION
NWS TULSA OK
942 AM CST THU JAN 1 2015 .DISCUSSION... THE FORECAST FOR TODAY HAS A HUGE BUST POTENTIAL. IT ALL HINGES ON THE LOCATION OF THE FREEZING LINE AND IF THE HRRR QPF PANS OUT. THE FREEZING LINE IS NOW LOCATED ACROSS SOUTHEAST OKLAHOMA INTO WEST-CENTRAL ARKANSAS. HOWEVER...THERE MAY STILL SOME POCKETS OF BELOW FREEZING TEMPERATURES IN THIS AREA. IT IS BASICALLY GOING TO BE RACE BETWEEN THE PRECIPITATION SHIELD AND THE FREEZING LINE...TO DETERMINE THE PRECIPITATION TYPE ACROSS NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON. WILL CONTINUE WINTER WEATHER ADVISORY AS IT IS FOR NOW WITH MAINLY FREEZING RAIN AND SLEET EXPECTED ACROSS NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON. LIGHT ACCUMULATIONS OF ICE ARE EXPECTED. HOWEVER...TRAVEL IMPACTS CAN BE GREAT WITH EVEN A THIN GLAZE OF ICE. WILL MORE THAN LIKELY SEE MAINLY RAIN ACROSS THE SOUTH WITH PATCHES OF SLEET. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM THURSDAY FOR OKZ049-OKZ053- OKZ060-OKZ061-OKZ062-OKZ063-OKZ064-OKZ065-OKZ066-OKZ067- OKZ068-OKZ069-OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075- OKZ076. AR...WINTER WEATHER ADVISORY UNTIL 6 PM THURSDAY FOR ARZ001-ARZ002- ARZ010-ARZ011-ARZ019-ARZ020-ARZ029. && $$ SHORT TERM...10
AREA FORECAST DISCUSSION...UPDATED
NWS NORMAN OK
555 AM CST THU JAN 1 2015 .AVIATION... 01/12Z TAFS...PRIMARILY MVFR/IFR CONDITIONS EXPECTED MOST OF THE FORECAST PERIOD. AREAS OF FREEZING DRIZZLE/FREEZING RAIN EXPECTED TO AFFECT ALL BUT FAR NORTHERN OKLAHOMA TERMINALS...WHERE PRECIP WILL MAINLY BE SNOW THIS MORNING INTO EARLY AFTERNOON. MOST PERSISTENT LIGHT FZDZ/FZRA EXPECTED NEAR AND SOUTH OF KHBR AND KOUN. BREAK IN MOST OF THE PRECIP EXPECTED TOWARD AND AFTER 20-22Z BUT CIGS/VSBY WILL KEEP IFR/MVFR CONDITIONS GOING ALL BUT NORTHERN OKLAHOMA SITES. WIDESPREAD FREEZING/FROZEN PRECIP EXPECTED TO SPREAD OVER REGION JUST AFTER THIS TAF PERIOD AND LASTING MOST OF THE DAY FRIDAY. && .PREV DISCUSSION... /ISSUED 452 AM CST THU JAN 1 2015/ DISCUSSION... WAVE NUMBER ONE OF PRECIPITATION IS ONGOING ACROSS SOUTHERN OKLAHOMA AND WESTERN TEXAS THIS MORNING. RADAR TRENDS SHOW ENHANCEMENT OF RADAR REFLECTIVITY IN THE TEXAS PANHANDLE. THE CELLULAR STRUCTURE AND ENHANCED REFLECTIVITY SUGGEST THIS IS ASSOCIATED WITH SLEET. BOTH THE HRRR AND RAP SUGGEST THIS WILL CONTINUE TO DEVELOP AND MOVE EASTWARD WITH THE POTENTIAL FOR A WINTRY MIX EVEN NORTH OF I-40 THIS MORNING INTO EARLY AFTERNOON. THEREFORE...DECIDED TO EXPAND THE WINTER WEATHER ADVISORY FARTHER NORTH. WAVE NUMBER ONE WILL EXIT THE AREA LATE AFTERNOON INTO EARLY EVENING. ATTENTION THEN TURNS TO SECOND WAVE OF PRECIPITATION THAT IS ASSOCIATED WITH THE MAIN UPPER LEVEL LOW. A MORE WIDESPREAD PRECIPITATION EVENT IS EXPECTED. PRECIPITATION WILL LIKELY DEVELOP IN WESTERN NORTH TEXAS EARLY FRIDAY MORNING AND LIFT NORTHEASTWARD THROUGH THE DAY FRIDAY. BECAUSE OF THE EARLY ONSET...THERE IS CONCERN OF A SIGNIFICANT ICING EVENT ACROSS WESTERN NORTH TEXAS. THE FORECAST ON FRIDAY WILL DEPEND ON THE EVOLUTION OF THE SFC 32F WETBULB TEMPERATURE. LATEST GUIDANCE SUGGESTS THIS COULD BE VERY CLOSE TO THE I-44 CORRIDOR BY FRIDAY AFTERNOON. OPTED FOR A MIX OF RAIN/FREEZING RAIN ALONG I-44...WITH A FREEZING RAIN/SLEET MIX NORTHWEST AND ALL RAIN SOUTHEAST. A TRANSITION TO SNOW WILL OCCUR LATE FRIDAY INTO SATURDAY AS THE UPPER LEVEL LOW PASSES THROUGH OKLAHOMA. BOTH THE PARALLEL GFS AND ECMWF STILL SUGGEST THERE COULD BE ACCUMULATING SNOW IN NORTHERN OKLAHOMA SATURDAY. THERE IS THE POTENTIAL THERE COULD BE ENOUGH ACCUMULATING SNOW FOR HEADLINES. THE REST OF OKLAHOMA AND WESTERN NORTH TEXAS COULD BE DRY SLOTTED SATURDAY. AFTER COLLABORATION WITH SURROUNDING OFFICES...DECIDED TO HOLD OFF ON ANY HEADLINES FOR FRIDAY AND SATURDAY. NEVERTHELESS...HEADLINES WILL LIKELY BE REQUIRED FOR PARTS OF THE AREA FRIDAY INTO SATURDAY FOR ACCUMULATING ICE AND/OR SNOW. STAY-TUNED! BEYOND SATURDAY...A RATHER COLD DAY IS EXPECTED ON SUNDAY BEHIND THE STORM SYSTEM. TEMPERATURES WILL SLOWLY MODERATE BEFORE ANOTHER COLD FRONT APPROACHES THE REGION AROUND MID-WEEK. THE FORECAST IS DRY BEYOND SATURDAY. MAHALE && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 30 27 34 31 / 70 20 60 70 HOBART OK 28 24 33 29 / 80 20 50 60 WICHITA FALLS TX 30 29 34 32 / 90 60 80 70 GAGE OK 29 18 33 22 / 30 0 20 40 PONCA CITY OK 31 24 33 30 / 30 10 30 70 DURANT OK 32 32 36 36 / 90 50 80 80 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR OKZ021>048-050>052. TX...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR TXZ083>090. && $$ 11/10/11
AREA FORECAST DISCUSSION
NWS NORMAN OK
452 AM CST THU JAN 1 2015 .DISCUSSION... WAVE NUMBER ONE OF PRECIPITATION IS ONGOING ACROSS SOUTHERN OKLAHOMA AND WESTERN TEXAS THIS MORNING. RADAR TRENDS SHOW ENHANCEMENT OF RADAR REFLECTIVITY IN THE TEXAS PANHANDLE. THE CELLULAR STRUCTURE AND ENHANCED REFLECTIVITY SUGGEST THIS IS ASSOCIATED WITH SLEET. BOTH THE HRRR AND RAP SUGGEST THIS WILL CONTINUE TO DEVELOP AND MOVE EASTWARD WITH THE POTENTIAL FOR A WINTRY MIX EVEN NORTH OF I-40 THIS MORNING INTO EARLY AFTERNOON. THEREFORE...DECIDED TO EXPAND THE WINTER WEATHER ADVISORY FARTHER NORTH. WAVE NUMBER ONE WILL EXIT THE AREA LATE AFTERNOON INTO EARLY EVENING. ATTENTION THEN TURNS TO SECOND WAVE OF PRECIPITATION THAT IS ASSOCIATED WITH THE MAIN UPPER LEVEL LOW. A MORE WIDESPREAD PRECIPITATION EVENT IS EXPECTED. PRECIPITATION WILL LIKELY DEVELOP IN WESTERN NORTH TEXAS EARLY FRIDAY MORNING AND LIFT NORTHEASTWARD THROUGH THE DAY FRIDAY. BECAUSE OF THE EARLY ONSET...THERE IS CONCERN OF A SIGNIFICANT ICING EVENT ACROSS WESTERN NORTH TEXAS. THE FORECAST ON FRIDAY WILL DEPEND ON THE EVOLUTION OF THE SFC 32F WETBULB TEMPERATURE. LATEST GUIDANCE SUGGESTS THIS COULD BE VERY CLOSE TO THE I-44 CORRIDOR BY FRIDAY AFTERNOON. OPTED FOR A MIX OF RAIN/FREEZING RAIN ALONG I-44...WITH A FREEZING RAIN/SLEET MIX NORTHWEST AND ALL RAIN SOUTHEAST. A TRANSITION TO SNOW WILL OCCUR LATE FRIDAY INTO SATURDAY AS THE UPPER LEVEL LOW PASSES THROUGH OKLAHOMA. BOTH THE PARALLEL GFS AND ECMWF STILL SUGGEST THERE COULD BE ACCUMULATING SNOW IN NORTHERN OKLAHOMA SATURDAY. THERE IS THE POTENTIAL THERE COULD BE ENOUGH ACCUMULATING SNOW FOR HEADLINES. THE REST OF OKLAHOMA AND WESTERN NORTH TEXAS COULD BE DRY SLOTTED SATURDAY. AFTER COLLABORATION WITH SURROUNDING OFFICES...DECIDED TO HOLD OFF ON ANY HEADLINES FOR FRIDAY AND SATURDAY. NEVERTHELESS...HEADLINES WILL LIKELY BE REQUIRED FOR PARTS OF THE AREA FRIDAY INTO SATURDAY FOR ACCUMULATING ICE AND/OR SNOW. STAY-TUNED! BEYOND SATURDAY...A RATHER COLD DAY IS EXPECTED ON SUNDAY BEHIND THE STORM SYSTEM. TEMPERATURES WILL SLOWLY MODERATE BEFORE ANOTHER COLD FRONT APPROACHES THE REGION AROUND MID-WEEK. THE FORECAST IS DRY BEYOND SATURDAY. MAHALE && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 30 27 34 31 / 70 20 60 70 HOBART OK 28 24 33 29 / 80 20 50 60 WICHITA FALLS TX 30 29 34 32 / 90 60 80 70 GAGE OK 29 18 33 22 / 30 0 20 40 PONCA CITY OK 31 24 33 30 / 30 10 30 70 DURANT OK 32 32 36 36 / 90 50 80 80 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR OKZ021>048-050>052. TX...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR TXZ083>090. && $$ 11/10
AREA FORECAST DISCUSSION...UPDATED
NWS AUSTIN/SAN ANTONIO TX
714 AM CST THU JAN 1 2015 .UPDATE... PLEASE SEE THE 12Z AVIATION DISCUSSION BELOW. && .AVIATION... CIGS WILL CONTINUE TO LOWER THROUGHOUT THE DAY AS LIGHT PRECIPITATION CONTINUES TO MOVE FROM SOUTHWEST TO NORTHEAST ACROSS THE REGION. MOST TAF SITES ARE EITHER CURRENTLY IFR OR WILL DROP INTO IFR WITHIN THE NEXT COUPLE OF HOURS. ALL LIQUID PRECIPITATION IS EXPECTED AT OUR TAF SITES AS TEMPERATURES REMAIN ABOVE FREEZING. && .PREV DISCUSSION... /ISSUED 417 AM CST THU JAN 1 2015/ SHORT TERM (TODAY THROUGH FRIDAY)... LIGHT FREEZING PRECIPITATION CONTINUES OVER THE ADVY AND WARNING AREAS OF THE SRN EDWARDS PLATEAU...HILL COUNTRY AND BALCONES ESCARPMENT. A CLUSTER OF WEAK THUNDERSTORMS CROSSED FROM NRN MEXICO AND LOOKS TO BE PRODUCING A BRIGHT BAND OF WHAT IS PROBABLY SNOW MELTING INTO RAIN AND POSSIBLY A PARTIAL MELT/REFREEZE TO SLEET AND GRAUPEL. THIS CONVECTIVE AREA IS LOSING THE CELLULAR STRUCTURE AND SHOULD CONTINUE TO WEAKEN AS IT LIFTS NE. THUS WILL LEAVE OUT THE MENTION OF THUNDER AND LET NOWCASTS HANDLE WHAT SHOULD BE A SHORT-LIVED EVENT. THE DAYBREAK EMERGENCE OF CONVECTIVE SLEET BAND IS EXPECTED TO TRACK RIGHT ALONG THE EASTERN PART OF THE BALCONES ESCARPMENT. THUS AM HESITANT TO WARM MORNING TEMPERATURE FORECASTS TO MATCH THE CURRENT TRENDS HOLDING ABOVE FREEZING. HI-RES MODELS HAVE KEPT WITH THE CONVECTIVE BANDING AREA FORMING FARTHER NORTH...BUT THE LATEST RUNS OF THE HRRR DEPICT THE ONGOING CONVECTIVE AREA WELL AND SEND IT ACROSS THE AUSTIN METRO AREA AND NW PART OF THE SAN ANTONIO METRO AREA THROUGH DAYBREAK. WHILE THIS CLUSTER OF MODERATE PRECIPITATION COULD LOWER TEMPS TO FREEZING BRIEFLY...EXPECT THE WEAKENING TREND TO ALLOW MOST AREAS IN THE ADVISORY TO HOLD ONTO ABOVE FREEZING TEMPERATURES WITH MORE ISOLATED FROZEN CONDITIONS POSSIBLE AT HIGHER ELEVATIONS. A SECONDARY CONVECTIVE BAND REMAINS IN THE HRRR PICTURE WHICH SHOULD POTENTIALLY ADD TO THE FREEZING RAIN/SLEET MIX OVER THE WARNING AREA AT AROUND DAYBREAK. THUS THE ONGOING WINTER STORM WARNING AND WINTER WEATHER ADVISORY AREA IS THUS CONSIDERED APPROPRIATE AND NO WSW UPDATES ARE PLANNED. THE CONSENSUS MODEL POPULATION OF THE TEMPERATURES IN THE GRIDDED DATA SUGGESTED A QUICK WARM- UP TO ABOVE FREEZING...BUT WE FAVOR A MORE GRADUAL RISE IN THE MORNING PERIOD WHERE ICING HAS OCCURRED. BY NOON...MODEL SOUNDINGS SUGGEST THERE SHOULD BE AMPLE TIME FOR THE WARMING TO HAVE OCCURRED...AS THE FRONTAL INVERSION SHOULD CONTINUE TO BE MODIFIED BY FALLING RAIN AND DRIZZLE. A COLD RAIN REMAINS IN THE PICTURE THROUGH FRIDAY. TEMPERATURES SHOULD BE ALMOST FLAT FROM THIS AFTERNOON THROUGH LATE FRIDAY MORNING BEFORE WARMING INTO THE 40S OVER MOST AREAS LATE FRIDAY. DESPITE THE HIGH POPS BENEATH THE SOLID OVERRUNNING PATTERN...QPF AMOUNTS REMAIN CONSERVATIVE AND GENERALLY BELOW 1/2 INCH. LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... THE EASTWARD EJECTION OF A SLOW MOVING UPPER LOW BRINGS A SLIGHTLY MORE CONVECTIVE ENVIRONMENT TO TX BY FRIDAY EVENING. THE INCREASED POTENTIAL FOR THUNDER TRANSLATES TO SLIGHTLY HIGHER QPF AMOUNTS WITH ANOTHER 1/2 INCH OF RAIN POSSIBLE IN THE FRIDAY NIGHT PERIOD ALONE. MODEL CONSENSUS REMAINS IN GOOD AGREEMENT TO BRING DECREASING CLOUDS AND RAIN CHANCES BY MIDDAY SATURDAY AND PROBABLY THE WARMEST TEMPS OF THE WEEK. THIS IS BECAUSE ANOTHER FRONT ARRIVES BY SUNDAY MORNING. THE ECMWF TRENDED SHARPLY COLDER FROM THIS FRONT WITH A MUCH ENHANCED POLAR TROUGH OVER THE EASTERN US. THE GFS HAS ALSO TRENDED SLIGHTLY COLDER...SO A BLEND OF THESE TWO MODELS LOOKS REASONABLE. AM HESITANT TO BUY INTO THE ECMWF BASED GUIDANCE THAT PROJECTED MIDDLE TEENS OVER THE HILL COUNTRY MONDAY MORNING. THE COLD PATTERN IS SHOWN BY BOTH THE GFS AND ECMWF SOLUTIONS TO BE SHORT-LIVED WITH A PROGRESSIVE ZONAL PATTERN PUSHING AN UPPER RIDGE OVER TX BY MIDWEEK. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 39 38 43 40 59 / 80 90 80 80 30 AUSTIN BERGSTROM INTL AIRPORT 40 37 43 39 58 / 80 90 80 80 30 NEW BRAUNFELS MUNI AIRPORT 41 39 45 42 61 / 70 80 70 80 30 BURNET MUNI AIRPORT 38 35 40 37 57 / 90 90 80 80 20 DEL RIO INTL AIRPORT 41 41 49 41 61 / 40 50 40 50 - GEORGETOWN MUNI AIRPORT 40 36 41 38 56 / 90 90 80 80 30 HONDO MUNI AIRPORT 41 39 47 40 62 / 50 60 50 60 20 SAN MARCOS MUNI AIRPORT 40 38 44 41 59 / 70 80 70 80 30 LA GRANGE - FAYETTE REGIONAL 43 41 47 44 59 / 70 70 80 80 40 SAN ANTONIO INTL AIRPORT 41 39 46 42 61 / 60 80 60 70 20 STINSON MUNI AIRPORT 42 40 46 42 62 / 60 70 60 70 20 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING COUNTIES: BEXAR...COMAL...HAYS...KINNEY...MEDINA...TRAVIS... UVALDE...WILLIAMSON. WINTER STORM WARNING UNTIL NOON CST TODAY FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...GILLESPIE... KENDALL...KERR...LLANO...REAL...VAL VERDE. && $$ MESOSCALE/AVIATION...18 SYNOPTIC/GRIDS...24
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
417 AM CST THU JAN 1 2015 .SHORT TERM (TODAY THROUGH FRIDAY)... LIGHT FREEZING PRECIPITATION CONTINUES OVER THE ADVY AND WARNING AREAS OF THE SRN EDWARDS PLATEAU...HILL COUNTRY AND BALCONES ESCARPMENT. A CLUSTER OF WEAK THUNDERSTORMS CROSSED FROM NRN MEXICO AND LOOKS TO BE PRODUCING A BRIGHT BAND OF WHAT IS PROBABLY SNOW MELTING INTO RAIN AND POSSIBLY A PARTIAL MELT/REFREEZE TO SLEET AND GRAUPEL. THIS CONVECTIVE AREA IS LOSING THE CELLULAR STRUCTURE AND SHOULD CONTINUE TO WEAKEN AS IT LIFTS NE. THUS WILL LEAVE OUT THE MENTION OF THUNDER AND LET NOWCASTS HANDLE WHAT SHOULD BE A SHORT-LIVED EVENT. THE DAYBREAK EMERGENCE OF CONVECTIVE SLEET BAND IS EXPECTED TO TRACK RIGHT ALONG THE EASTERN PART OF THE BALCONES ESCARPMENT. THUS AM HESITANT TO WARM MORNING TEMPERATURE FORECASTS TO MATCH THE CURRENT TRENDS HOLDING ABOVE FREEZING. HI-RES MODELS HAVE KEPT WITH THE CONVECTIVE BANDING AREA FORMING FARTHER NORTH...BUT THE LATEST RUNS OF THE HRRR DEPICT THE ONGOING CONVECTIVE AREA WELL AND SEND IT ACROSS THE AUSTIN METRO AREA AND NW PART OF THE SAN ANTONIO METRO AREA THROUGH DAYBREAK. WHILE THIS CLUSTER OF MODERATE PRECIPITATION COULD LOWER TEMPS TO FREEZING BRIEFLY...EXPECT THE WEAKENING TREND TO ALLOW MOST AREAS IN THE ADVISORY TO HOLD ONTO ABOVE FREEZING TEMPERATURES WITH MORE ISOLATED FROZEN CONDITIONS POSSIBLE AT HIGHER ELEVATIONS. A SECONDARY CONVECTIVE BAND REMAINS IN THE HRRR PICTURE WHICH SHOULD POTENTIALLY ADD TO THE FREEZING RAIN/SLEET MIX OVER THE WARNING AREA AT AROUND DAYBREAK. THUS THE ONGOING WINTER STORM WARNING AND WINTER WEATHER ADVISORY AREA IS THUS CONSIDERED APPROPRIATE AND NO WSW UPDATES ARE PLANNED. THE CONSENSUS MODEL POPULATION OF THE TEMPERATURES IN THE GRIDDED DATA SUGGESTED A QUICK WARM- UP TO ABOVE FREEZING...BUT WE FAVOR A MORE GRADUAL RISE IN THE MORNING PERIOD WHERE ICING HAS OCCURRED. BY NOON...MODEL SOUNDINGS SUGGEST THERE SHOULD BE AMPLE TIME FOR THE WARMING TO HAVE OCCURRED...AS THE FRONTAL INVERSION SHOULD CONTINUE TO BE MODIFIED BY FALLING RAIN AND DRIZZLE. A COLD RAIN REMAINS IN THE PICTURE THROUGH FRIDAY. TEMPERATURES SHOULD BE ALMOST FLAT FROM THIS AFTERNOON THROUGH LATE FRIDAY MORNING BEFORE WARMING INTO THE 40S OVER MOST AREAS LATE FRIDAY. DESPITE THE HIGH POPS BENEATH THE SOLID OVERRUNNING PATTERN...QPF AMOUNTS REMAIN CONSERVATIVE AND GENERALLY BELOW 1/2 INCH. && .LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... THE EASTWARD EJECTION OF A SLOW MOVING UPPER LOW BRINGS A SLIGHTLY MORE CONVECTIVE ENVIRONMENT TO TX BY FRIDAY EVENING. THE INCREASED POTENTIAL FOR THUNDER TRANSLATES TO SLIGHTLY HIGHER QPF AMOUNTS WITH ANOTHER 1/2 INCH OF RAIN POSSIBLE IN THE FRIDAY NIGHT PERIOD ALONE. MODEL CONSENSUS REMAINS IN GOOD AGREEMENT TO BRING DECREASING CLOUDS AND RAIN CHANCES BY MIDDAY SATURDAY AND PROBABLY THE WARMEST TEMPS OF THE WEEK. THIS IS BECAUSE ANOTHER FRONT ARRIVES BY SUNDAY MORNING. THE ECMWF TRENDED SHARPLY COLDER FROM THIS FRONT WITH A MUCH ENHANCED POLAR TROUGH OVER THE EASTERN US. THE GFS HAS ALSO TRENDED SLIGHTLY COLDER...SO A BLEND OF THESE TWO MODELS LOOKS REASONABLE. AM HESITANT TO BUY INTO THE ECMWF BASED GUIDANCE THAT PROJECTED MIDDLE TEENS OVER THE HILL COUNTRY MONDAY MORNING. THE COLD PATTERN IS SHOWN BY BOTH THE GFS AND ECMWF SOLUTIONS TO BE SHORT-LIVED WITH A PROGRESSIVE ZONAL PATTERN PUSHING AN UPPER RIDGE OVER TX BY MIDWEEK. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 39 38 43 40 59 / 80 90 80 80 30 AUSTIN BERGSTROM INTL AIRPORT 40 37 43 39 58 / 80 90 80 80 30 NEW BRAUNFELS MUNI AIRPORT 41 39 45 42 61 / 70 80 70 80 30 BURNET MUNI AIRPORT 38 35 40 37 57 / 90 90 80 80 20 DEL RIO INTL AIRPORT 41 41 49 41 61 / 40 50 40 50 - GEORGETOWN MUNI AIRPORT 40 36 41 38 56 / 90 90 80 80 30 HONDO MUNI AIRPORT 41 39 47 40 62 / 50 60 50 60 20 SAN MARCOS MUNI AIRPORT 40 38 44 41 59 / 70 80 70 80 30 LA GRANGE - FAYETTE REGIONAL 43 41 47 44 59 / 70 70 80 80 40 SAN ANTONIO INTL AIRPORT 41 39 46 42 61 / 60 80 60 70 20 STINSON MUNI AIRPORT 42 40 46 42 62 / 60 70 60 70 20 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR THE FOLLOWING COUNTIES: BEXAR...COMAL...HAYS...KINNEY...MEDINA...TRAVIS... UVALDE...WILLIAMSON. WINTER STORM WARNING UNTIL NOON CST TODAY FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...GILLESPIE... KENDALL...KERR...LLANO...REAL...VAL VERDE. && $$ MESOSCALE/AVIATION...24 SYNOPTIC/GRIDS...18
AREA FORECAST DISCUSSION...UPDATE FOR AVIATION
NWS LITTLE ROCK AR
1150 AM CST THU JAN 1 2015 .AVIATION... OVERALL VFR CEILINGS AND FLIGHT CONDITIONS WILL START THE FORECAST. THE AREA OF MAINLY LIGHT TO PATCHY MODERATE RAIN...WITH A FEW SPOTS MIXED WITH LIGHT SLEET OR LIGHT FREEZING RAIN IN WESTERN TO NORTHWEST AR...ARE SPREADING OVER AR. TEMPS WILL HOLD ABOVE FREEZING OVER MOST LOCALS AND RAIN WILL BE SEEN...WITH THE GREATEST CHANCE OF LIGHT SLEET OR LIGHT FREEZING RAIN IN WESTERN TO NORTHERN AR. PATCHY MVFR CEILINGS WILL BE POSSIBLE WITH THE HEAVIER PRECIP AREAS. WINDS ARE LIGHT FROM THE NE TO SE. TONIGHT...CEILINGS WILL GRADUALLY LOWER TO MAINLY MVFR CONDITIONS WITH THE LIGHT TO AT TIMES MODERATE RAIN. PATCHY LIGHT FREEZING RAIN AND SLEET MAY BE SEEN OVER WESTERN AND NORTHERN AR. ICING WILL BE POSSIBLE IN CLOUDS. THE CHANCE OF RAIN WILL CONTINUE ON FRIDAY. (59) && .PREV DISCUSSION... /ISSUED 1059 AM CST THU JAN 1 2015/ .UPDATE... PRECIPITATION HAS INCREASED ACROSS PORTIONS OF SOUTHEAST ARKANSAS THROUGH THE MORNING HOURS...WITH ONLY A FEW BRIEF REPORTS OF SLEET COMING IN. TEMPERATURES AROUND THE STATE THIS MORNING NOW HAVE MOSTLY RISEN ABOVE FREEZING. THE FEW EXCEPTIONS ARE IN THE HIGHER ELEVATIONS ACROSS WESTERN AND NORTHWEST ARKANSAS. HRRR CONTINUES TO BRING A SECOND ROUND OF PRECIPITATION ACROSS NORTHWEST ARKANSAS LATER THIS AFTERNOON. DO FULLY EXPECT SOME EVAPORATIVE COOLING THROUGH THE DAY TODAY AS ENVIRONMENT MOISTENS UP. CURRENT THINKING IS THAT THIS WILL HAVE NO NET EFFECT ON TEMPS AND THEY WILL REMAIN STATIONARY THROUGH THE AFTERNOON. FORECAST IS IN GOOD SHAPE...AND JUST MADE SOME MINOR TWEAKS TO TEMPERATURES TO REFLECT THE CURRENT TRENDS. && .PREV DISCUSSION... /ISSUED 625 AM CST THU JAN 1 2015/ AVIATION...01/12Z TAF CYCLE VFR CONDS WL START OFF THE PD...BUT CONDS WL DETERIORATE TODAY AS PRECIP DVLPS AND OVERSPREADS THE FA. PARTS OF WRN AND NRN AR WL SEE A MIX OF LGT FRZG RAIN AND SLEET THIS MRNG BEFORE CHANGING OVR TO JUST RAIN BY THIS AFTN. SOME FRZG DRIZZLE WL BE POSSIBLE TNGT OVR NRN AR. ELSEWHERE...A BRIEF PD OF RAIN AND SLEET WL OCCUR THIS MRNG BEFORE PRECIP BCMS JUST A COLD RAIN. /44/ PREV DISCUSSION... /ISSUED 231 AM CST THU JAN 1 2015/ SHORT TERM...TODAY THROUGH SUNDAY TEMPS ACROSS THE CWA THIS MORNING ARE REMAINING STEADY IN THE 30S FOR MOST LOCATIONS...WITH MOST LOCATIONS ABOVE FREEZING. THE CLOUD COVER HAS KEPT THESE TEMPS FROM FALLING...AND WILL LIKELY SEE TEMPS REMAIN STEADY THROUGH SUNRISE. DRY AIR IS IN PLACE HOWEVER...WITH DEWPTS IN THE UPPER TEENS TO MID 20S. WATER VAPOR IMAGERY IS SHOWING A MOISTURE PLUME STRETCHING FROM THE PACIFIC...LIFTING NE INTO TX AND OK THIS MORNING...WITH PRECIP EVIDENT IN NRN TX AND RECENTLY SRN OK AS SEEN IN REGIONAL RADAR IMAGERY. AS THIS MOISTURE APPROACHES THE WRN AND SWRN COUNTIES THIS MORNING...DO EXPECT SOME EVAPORATIVE COOLING AS MOISTURE FALLS THROUGH THE DRY LAYER NEAR THE SFC. HAVE TEMPS DROPPING SEVERAL DEG AT THE ONSET OF PRECIP...WHICH WILL BE THE PRIMARY TIME FOR ANY WINTRY PRECIP. INITIALLY...A PERIOD OF SLEET AND FREEZING RAIN WILL BE SEEN AS THE COLUMN SATURATES DURING THE MORNING HRS. GIVEN TEMPS ARE ALREADY WARMER THAN EARLIER EXPECTED AT THIS TIME...THE POTENTIAL FOR WIDESPREAD WINTER WX HAZARDS IS EVEN LOWER THAN EARLIER EXPECTED. AS A RESULT...THINKING ANY SLEET OR ICE ACCUMULATIONS WILL BE LIGHT...AND LIMITED TO THE HIGHER TERRAIN OF THE OUACHITAS AND OZARKS...AND OTHER ISOLATED AREAS ACROSS THE FAR WRN AND NWRN COUNTIES. ANY TRAVEL HAZARDS THIS NEW YEARS MORNING WILL BE LIMITED TO THESE LOCATIONS...ESPECIALLY ON BRIDGES AND OVERPASSES. WILL CONTINUE TO EMPHASIZE ANY WINTRY WX TRAVEL CONCERNS IN AN UPDATED SPS THIS MORNING. LOCATIONS FURTHER EAST WILL ALSO SEE SOME SLEET OR PATCHY FREEZING RAIN AT THE ONSET OF THE PRECIP...BUT TEMPS THROUGHOUT THE ENTIRE THERMAL PROFILE WILL WARM OVER TIME...LEADING TO JUST A COLD RAIN BY LATER THIS MORNING AND ESPECIALLY THIS AFTERNOON. THE HIGHEST PRECIP RATES WILL BE ACROSS THE SRN HALF OF THE CWA WHERE TEMPS ARE WARMEST. LIGHTER PRECIP RATES WILL BE SEEN ACROSS THE NRN COUNTIES...WHERE TEMPS MAY REMAIN COLD ENOUGH THIS AFTERNOON TO SEE SOME FREEZING RAIN MIX WITH THE RAIN...ESPECIALLY IN THE HIGHER TERRAIN OF THE OZARKS AND NEAR THE MO BORDER. ONLY MINOR ICE ACCUMULATIONS ARE EXPECTED THIS AFTERNOON IN AREAS WHERE THE FREEZING RAIN OCCURS. THIS EVENING...MOST LOCATIONS WILL SEE ALL RAINFALL AS TEMPS WILL REMAIN STEADY OR EVEN WARM A DEG OR TWO BY FRI MORNING. MOST OF THE PRECIP ACTIVITY WILL ALSO HAVE SHIFTED FURTHER SOUTH...WITH NRN LOCATIONS LIKELY SEEING DRY CONDITIONS TONIGHT. AS A RESULT...DROP POPS ALONG THE MO BORDER TO ONLY SLIGHT CHANCE. IF ANY PRECIP WERE TO FALL ACROSS THE NRN COUNTIES...MAINLY RAIN IS EXPECTED...THOUGH A FEW SPOTS IN THE HIGHER TERRAIN COULD AGAIN SEE SOME FREEZING RAIN MIX IN WITH THE RAIN. EVEN THIS CLOSE TO THE ONSET OF THIS MINOR WINTER WX EPISODE...THERE DOES REMAIN SOME UNCERTAINTY REGARDING TEMPS. SOME ADJUSTMENTS IN THE FORECAST REMAIN POSSIBLE...ESPECIALLY CONSIDERING SOME LOCATIONS WILL BE SO NEAR THE FREEZING MARK. ANY CHANGES IN THE EXPECTED TEMPS COULD ALTER THE POTENTIAL FROZEN PRECIP ACCUMULATION...RESULTING IN INCREASED WINTER WX TRAVEL HAZARDS. PLEASE REFER TO THE LATEST FORECASTS UPDATES THIS NEW YEARS DAY...ESPECIALLY IN THE HIGHER TERRAIN OF THE OUACHITAS AND OZARKS...THE WRN COUNTIES...AND AREAS ALONG THE MO BORDER. ENOUGH WARMING WILL HAVE OCCURRED FOR FRI INTO SAT TO SEE ALL LIQUID PRECIP. THE SW FLOW ALOFT WILL INTENSIFY FRI INTO SAT...WITH WIDESPREAD SHRA AND EVEN SOME RUMBLES OF THUNDER POSSIBLE ACROSS THE CWA. SOME LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE...THOUGH ONLY WIDESPREAD RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE CURRENTLY EXPECTED. AS A RESULT...A FLASH FLOOD WATCH IS NOT EXPECTED AT THIS TIME. THE STORM SYSTEM WILL EXIT THE REGION SAT INTO SAT NIGHT...WITH DRIER AIR MOVING INTO THE STATE BY THE AFTERNOON HRS SAT. AS A RESULT...HAVE POPS DECREASING RAPIDLY BY SAT AFTERNOON FROM SW TO NE. SOME LINGERING MOISTURE COULD BE SEEN ACROSS THE NRN COUNTIES SAT NIGHT...WITH SOME SPRINKLES OR A FEW SNOW FLAKES POSSIBLE. A COLD FRONT WILL SURGE THROUGH THE STATE ON SUN...WITH COLDER AND DRIER CONDITIONS MOVING INTO THE REGION. CHANCES FOR ANY PRECIP WILL BE LOW TO END THE SHORT TERM PERIOD. LONG TERM...MONDAY THROUGH WEDNESDAY MODELS ARE IN DECENT AGREEMENT THIS MRNG WITH OVERALL FCST TRENDS THRU THE PD. A WESTERLY FLOW ALOFT ON MON WL EVENTUALLY TURN NWLY FOR TUE AND WED AS A LONG WV TROF SHARPENS OVR THE ERN HALF OF THE NATION. AS A RESULT...A SERIES OF CLIPPER TYPE SFC LOWS WL DROP SEWD AND BRING REINFORCING SHOTS OF COLDER AIR TO AR THRU THE MIDDLE OF THE WEEK. WITH LTL IN THE WAY OF LOW LVL MOISTURE RETURN ANTICIPATED...THE FCST WL RMN DRY. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 37 34 40 36 / 50 40 80 80 CAMDEN AR 36 36 42 40 / 100 80 90 80 HARRISON AR 35 32 40 34 / 30 20 50 80 HOT SPRINGS AR 37 34 41 38 / 90 60 90 80 LITTLE ROCK AR 38 35 41 38 / 80 60 90 80 MONTICELLO AR 37 35 42 42 / 100 80 90 80 MOUNT IDA AR 38 34 41 37 / 90 60 90 80 MOUNTAIN HOME AR 34 33 41 35 / 30 20 50 80 NEWPORT AR 37 34 40 38 / 50 50 80 80 PINE BLUFF AR 37 35 41 40 / 90 80 90 80 RUSSELLVILLE AR 37 34 41 37 / 80 40 80 80 SEARCY AR 36 33 40 37 / 60 50 90 80 STUTTGART AR 37 34 41 39 / 90 60 90 80 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 65
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
1059 AM CST THU JAN 1 2015 .UPDATE... PRECIPITATION HAS INCREASED ACROSS PORTIONS OF SOUTHEAST ARKANSAS THROUGH THE MORNING HOURS...WITH ONLY A FEW BRIEF REPORTS OF SLEET COMING IN. TEMPERATURES AROUND THE STATE THIS MORNING NOW HAVE MOSTLY RISEN ABOVE FREEZING. THE FEW EXCEPTIONS ARE IN THE HIGHER ELEVATIONS ACROSS WESTERN AND NORTHWEST ARKANSAS. HRRR CONTINUES TO BRING A SECOND ROUND OF PRECIPITATION ACROSS NORTHWEST ARKANSAS LATER THIS AFTERNOON. DO FULLY EXPECT SOME EVAPORATIVE COOLING THROUGH THE DAY TODAY AS ENVIRONMENT MOISTENS UP. CURRENT THINKING IS THAT THIS WILL HAVE NO NET EFFECT ON TEMPS AND THEY WILL REMAIN STATIONARY THROUGH THE AFTERNOON. FORECAST IS IN GOOD SHAPE...AND JUST MADE SOME MINOR TWEAKS TO TEMPERATURES TO REFLECT THE CURRENT TRENDS. && .PREV DISCUSSION... /ISSUED 625 AM CST THU JAN 1 2015/ AVIATION...01/12Z TAF CYCLE VFR CONDS WL START OFF THE PD...BUT CONDS WL DETERIORATE TODAY AS PRECIP DVLPS AND OVERSPREADS THE FA. PARTS OF WRN AND NRN AR WL SEE A MIX OF LGT FRZG RAIN AND SLEET THIS MRNG BEFORE CHANGING OVR TO JUST RAIN BY THIS AFTN. SOME FRZG DRIZZLE WL BE POSSIBLE TNGT OVR NRN AR. ELSEWHERE...A BRIEF PD OF RAIN AND SLEET WL OCCUR THIS MRNG BEFORE PRECIP BCMS JUST A COLD RAIN. /44/ PREV DISCUSSION... /ISSUED 231 AM CST THU JAN 1 2015/ SHORT TERM...TODAY THROUGH SUNDAY TEMPS ACROSS THE CWA THIS MORNING ARE REMAINING STEADY IN THE 30S FOR MOST LOCATIONS...WITH MOST LOCATIONS ABOVE FREEZING. THE CLOUD COVER HAS KEPT THESE TEMPS FROM FALLING...AND WILL LIKELY SEE TEMPS REMAIN STEADY THROUGH SUNRISE. DRY AIR IS IN PLACE HOWEVER...WITH DEWPTS IN THE UPPER TEENS TO MID 20S. WATER VAPOR IMAGERY IS SHOWING A MOISTURE PLUME STRETCHING FROM THE PACIFIC...LIFTING NE INTO TX AND OK THIS MORNING...WITH PRECIP EVIDENT IN NRN TX AND RECENTLY SRN OK AS SEEN IN REGIONAL RADAR IMAGERY. AS THIS MOISTURE APPROACHES THE WRN AND SWRN COUNTIES THIS MORNING...DO EXPECT SOME EVAPORATIVE COOLING AS MOISTURE FALLS THROUGH THE DRY LAYER NEAR THE SFC. HAVE TEMPS DROPPING SEVERAL DEG AT THE ONSET OF PRECIP...WHICH WILL BE THE PRIMARY TIME FOR ANY WINTRY PRECIP. INITIALLY...A PERIOD OF SLEET AND FREEZING RAIN WILL BE SEEN AS THE COLUMN SATURATES DURING THE MORNING HRS. GIVEN TEMPS ARE ALREADY WARMER THAN EARLIER EXPECTED AT THIS TIME...THE POTENTIAL FOR WIDESPREAD WINTER WX HAZARDS IS EVEN LOWER THAN EARLIER EXPECTED. AS A RESULT...THINKING ANY SLEET OR ICE ACCUMULATIONS WILL BE LIGHT...AND LIMITED TO THE HIGHER TERRAIN OF THE OUACHITAS AND OZARKS...AND OTHER ISOLATED AREAS ACROSS THE FAR WRN AND NWRN COUNTIES. ANY TRAVEL HAZARDS THIS NEW YEARS MORNING WILL BE LIMITED TO THESE LOCATIONS...ESPECIALLY ON BRIDGES AND OVERPASSES. WILL CONTINUE TO EMPHASIZE ANY WINTRY WX TRAVEL CONCERNS IN AN UPDATED SPS THIS MORNING. LOCATIONS FURTHER EAST WILL ALSO SEE SOME SLEET OR PATCHY FREEZING RAIN AT THE ONSET OF THE PRECIP...BUT TEMPS THROUGHOUT THE ENTIRE THERMAL PROFILE WILL WARM OVER TIME...LEADING TO JUST A COLD RAIN BY LATER THIS MORNING AND ESPECIALLY THIS AFTERNOON. THE HIGHEST PRECIP RATES WILL BE ACROSS THE SRN HALF OF THE CWA WHERE TEMPS ARE WARMEST. LIGHTER PRECIP RATES WILL BE SEEN ACROSS THE NRN COUNTIES...WHERE TEMPS MAY REMAIN COLD ENOUGH THIS AFTERNOON TO SEE SOME FREEZING RAIN MIX WITH THE RAIN...ESPECIALLY IN THE HIGHER TERRAIN OF THE OZARKS AND NEAR THE MO BORDER. ONLY MINOR ICE ACCUMULATIONS ARE EXPECTED THIS AFTERNOON IN AREAS WHERE THE FREEZING RAIN OCCURS. THIS EVENING...MOST LOCATIONS WILL SEE ALL RAINFALL AS TEMPS WILL REMAIN STEADY OR EVEN WARM A DEG OR TWO BY FRI MORNING. MOST OF THE PRECIP ACTIVITY WILL ALSO HAVE SHIFTED FURTHER SOUTH...WITH NRN LOCATIONS LIKELY SEEING DRY CONDITIONS TONIGHT. AS A RESULT...DROP POPS ALONG THE MO BORDER TO ONLY SLIGHT CHANCE. IF ANY PRECIP WERE TO FALL ACROSS THE NRN COUNTIES...MAINLY RAIN IS EXPECTED...THOUGH A FEW SPOTS IN THE HIGHER TERRAIN COULD AGAIN SEE SOME FREEZING RAIN MIX IN WITH THE RAIN. EVEN THIS CLOSE TO THE ONSET OF THIS MINOR WINTER WX EPISODE...THERE DOES REMAIN SOME UNCERTAINTY REGARDING TEMPS. SOME ADJUSTMENTS IN THE FORECAST REMAIN POSSIBLE...ESPECIALLY CONSIDERING SOME LOCATIONS WILL BE SO NEAR THE FREEZING MARK. ANY CHANGES IN THE EXPECTED TEMPS COULD ALTER THE POTENTIAL FROZEN PRECIP ACCUMULATION...RESULTING IN INCREASED WINTER WX TRAVEL HAZARDS. PLEASE REFER TO THE LATEST FORECASTS UPDATES THIS NEW YEARS DAY...ESPECIALLY IN THE HIGHER TERRAIN OF THE OUACHITAS AND OZARKS...THE WRN COUNTIES...AND AREAS ALONG THE MO BORDER. ENOUGH WARMING WILL HAVE OCCURRED FOR FRI INTO SAT TO SEE ALL LIQUID PRECIP. THE SW FLOW ALOFT WILL INTENSIFY FRI INTO SAT...WITH WIDESPREAD SHRA AND EVEN SOME RUMBLES OF THUNDER POSSIBLE ACROSS THE CWA. SOME LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE...THOUGH ONLY WIDESPREAD RAINFALL AMOUNTS OF 1 TO 2 INCHES ARE CURRENTLY EXPECTED. AS A RESULT...A FLASH FLOOD WATCH IS NOT EXPECTED AT THIS TIME. THE STORM SYSTEM WILL EXIT THE REGION SAT INTO SAT NIGHT...WITH DRIER AIR MOVING INTO THE STATE BY THE AFTERNOON HRS SAT. AS A RESULT...HAVE POPS DECREASING RAPIDLY BY SAT AFTERNOON FROM SW TO NE. SOME LINGERING MOISTURE COULD BE SEEN ACROSS THE NRN COUNTIES SAT NIGHT...WITH SOME SPRINKLES OR A FEW SNOW FLAKES POSSIBLE. A COLD FRONT WILL SURGE THROUGH THE STATE ON SUN...WITH COLDER AND DRIER CONDITIONS MOVING INTO THE REGION. CHANCES FOR ANY PRECIP WILL BE LOW TO END THE SHORT TERM PERIOD. LONG TERM...MONDAY THROUGH WEDNESDAY MODELS ARE IN DECENT AGREEMENT THIS MRNG WITH OVERALL FCST TRENDS THRU THE PD. A WESTERLY FLOW ALOFT ON MON WL EVENTUALLY TURN NWLY FOR TUE AND WED AS A LONG WV TROF SHARPENS OVR THE ERN HALF OF THE NATION. AS A RESULT...A SERIES OF CLIPPER TYPE SFC LOWS WL DROP SEWD AND BRING REINFORCING SHOTS OF COLDER AIR TO AR THRU THE MIDDLE OF THE WEEK. WITH LTL IN THE WAY OF LOW LVL MOISTURE RETURN ANTICIPATED...THE FCST WL RMN DRY. && .PRELIMINARY POINT TEMPS/POPS... BATESVILLE AR 37 34 40 36 / 50 40 80 80 CAMDEN AR 36 36 42 40 / 100 80 90 80 HARRISON AR 35 32 40 34 / 30 20 50 80 HOT SPRINGS AR 37 34 41 38 / 90 60 90 80 LITTLE ROCK AR 38 35 41 38 / 80 60 90 80 MONTICELLO AR 37 35 42 42 / 100 80 90 80 MOUNT IDA AR 38 34 41 37 / 90 60 90 80 MOUNTAIN HOME AR 34 33 41 35 / 30 20 50 80 NEWPORT AR 37 34 40 38 / 50 50 80 80 PINE BLUFF AR 37 35 41 40 / 90 80 90 80 RUSSELLVILLE AR 37 34 41 37 / 80 40 80 80 SEARCY AR 36 33 40 37 / 60 50 90 80 STUTTGART AR 37 34 41 39 / 90 60 90 80 && .LZK WATCHES/WARNINGS/ADVISORIES...NONE. && $$ 65
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
320 PM MST THU JAN 1 2015 .SHORT TERM...(TONIGHT THROUGH FRIDAY NIGHT) ISSUED AT 320 PM MST THU JAN 1 2015 THE HEAVIEST SNOWFALL OCCURRED LATE LAST NIGHT AND EARLY THIS MORNING ACROSS THE FOUR CORNERS REGION AS PREDICTED. REPORTS INDICATED 3 TO 5 INCHES OF SNOWFALL ACROSS MUCH OF THE REGION WITH SNOWFALL RATES NEAR 1 INCH PER HOUR IN SOME LOCATIONS. UPWARD FORCING IMPRESSIVE DURING THIS PERIOD AHEAD OF MID-LEVEL LOW CENTERED OVER NORTH-CENTRAL ARIZONA. AT 12Z...GOOD SURFACE CONVERGENCE IN EVIDENCE WITH SURFACE LOW CENTERED SOUTH OF KDRO ACCORDING TO RAP ANALYSIS. CONCURRENTLY...STRONG MID-LEVEL QG ASCENT OVER THE AREA TOPPED BY DIVERGENCE AT HIGHER LEVELS OF THE TROPOSPHERE WHERE LEFT EXIT REGION OF JET WAS POSITIONED. HOWEVER...DURING THE AFTERNOON COVERAGE AND SNOWFALL RATES HAD DECREASED SIGNIFICANTLY AS FORCING WAS DIMINISHED. SOUTHWESTWARD FLOWING JET ON THE BACK SIDE OF THE LOW CONTINUED TO PROPAGATE TO THE SOUTHWEST WHILE THE NORTHEASTWARD FLOWING JET ON THE LEADING EDGE MOVED OVER THE SOUTHERN PLAINS. THE SHEARING MOMENT BETWEEN THESE FLOWS STRETCHED THE LOW ALONG A SOUTHWEST TO NORTHEAST AXIS. AS A RESULT...DYNAMIC FORCING SHIFTED TO THE NORTHEAST CAUSING THE SURFACE AND 7H LOW CIRCULATIONS TO MOVE IN THAT DIRECTION. IN ADDITION TO THE LOSS OF DYNAMIC FORCING OVER THE SOUTHERN FORECAST AREA...OROGRAPHIC LIFT ALSO IMPACTED AS WEAK 7H LOW RECENTERED OVER THE SAN JUANS RESULTING IN WEAK AND VARIED WINDS. MODELS IN GOOD AGREEMENT...GENERATING VERY LITTLE QPF OVER MOST OF THE LOWER ELEVATIONS OF SOUTHEAST UTAH AND SOUTHWEST COLORADO DURING THE REMAINDER OF THE AFTERNOON AND THIS EVENING. THEREFORE ...WILL CANCEL WINTER STORM WARNINGS FOR THESE AREAS WITH THIS PACKAGE. HOWEVER...RAP13 AND HRRR BOTH INDICATED MODERATE SNOWFALL WILL CONTINUE ALONG A SOUTHWEST TO NORTHEAST ORIENTED BAND CENTERED OVER KCEZ. CONSEQUENTLY...WILL HOLD ONTO WINTER STORM WARNING FOR MODERATE SNOWFALL OVER THE SOUTHWEST CORNER OF THE STATE. IN ADDITION...LIGHT TO MODERATE SNOW SHOULD CONTINUE OVER THE SAN JUAN MOUNTAINS WHILE COVERAGE INCREASES OVER THE CENTRAL COLORADO MOUNTAINS AS DYNAMIC FORCING BECOMES MORE FAVORABLE. ONLY EXPECTING 2 TO 4 INCHES WITH LOCALLY HIGHER AMOUNTS IN THE CENTRAL MOUNTAINS SO WILL NOT EXPAND WINTER WEATHER ADVISORIES...THOUGH WILL CONTINUE HILITES ACROSS THE SAN JUANS INTO THE EVENING. SUBSIDENCE AND DRYING SETS IN LATER TONIGHT AS THE LOW CENTER IS DRIVEN SOUTHWARD BY THE SOUTHWESTWARD PROPAGATING JET ON THE LOW/S REAR FLANK. AS A RESULT...SNOWFALL WILL DIMINISH TO A FEW FLURRIES OVER THE CENTRAL MOUNTAINS AFTER MIDNIGHT. ANTICYCLONIC FLOW TO THE NORTH WILL INHIBIT SNOWFALL FRIDAY...THOUGH CANNOT ENTIRELY RULE OUT A FEW FLURRIES ALONG THE DIVIDE FRIDAY AFTERNOON. A SHORTWAVE TROUGH DROPPING TOWARD THE REGION FROM THE NORTHWEST WILL BE THE NEXT SNOW PRODUCER OVER THE FORECAST AREA POSSIBLY IMPACTING THE NORTHERN COLORADO MOUNTAINS FRIDAY NIGHT. THE AREA WILL BE UNDER WARM AIR ADVECTION WHILE FLOW REMAINS ANTICYCLONIC SO EXPECT SNOW WILL BE SCATTERED AND LIGHT...LIKELY HOLDING OFF UNTIL AFTER MIDNIGHT AS INDICATED BY FAVORED GFS AND ECMWF SOLUTIONS. WAA WILL ALLOW AIRMASS TO MODERATE A BIT...BUT TEMPERATURES WILL REMAIN COLDER THAN NORMAL FOR THE LATTER PART OF THE WEEK. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 320 PM MST THU JAN 1 2015 EXPECT SNOW WILL INCREASE OVER THE NORTHERN COLORADO MOUNTAINS SATURDAY AS THE SHORTWAVE TROUGH DISCUSSED PREVIOUSLY PUSHES ACROSS SOUTHWEST WYOMING IN THE MORNING...THEN ACROSS NORTHWEST COLORADO DURING THE AFTERNOON. MODELS NOT GENERATING SIGNIFICANT SNOW ACCUMULATIONS AT THIS POINT...BUT THERE REMAINS THE POTENTIAL FOR ADVISORY LEVEL SNOW ACROSS THE PARK...GORE...ELKHEAD...AND FLATTOP RANGES. A TIGHTENING GRADIENT ALOFT BENEATH THE NOSE OF A SOUTHWARD FLOWING 120 KT JET WILL GENERATE STRONG AND GUSTY NORTHWEST WINDS ACROSS THE RIDGES GENERATING AREAS OF BLOWING SNOW. MODELS INDICATED ANOTHER SHORTWAVE IN THE NORTHWESTERLIES WILL BRING SIMILAR CONDITIONS SUNDAY AFTERNOON THROUGH SUNDAY NIGHT... THOUGH IT APPEARS TO BE WEAKER THAN SATURDAY/S SYSTEM. HOWEVER... ECMWF INDICATED THAT OROGRAPHIC SNOWFALL COULD CONTINUE WELL INTO MONDAY SO MAY BE MORE IMPACTFUL THAN DEPICTED NOW. A RIDGE OF HIGH PRESSURE EASES EASTWARD FROM TUESDAY TO THURSDAY BRINGING DRY AND MILDER CONDITIONS FOR THE MIDDLE PART OF THE COMING WEEK. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING) ISSUED AT 320 PM MST THU JAN 1 2015 WITH THE STORM CIRCULATION CENTER MOVING THROUGH NORTH-CENTRAL THEN NORTHEAST NEW MEXICO TONIGHT AND THE JET RUNNING FURTHER SOUTH AND EAST...MOST OF THE PRECIPITATION HAS SHIFTED TO THE NORTHERN HEMISPHERE OF THE STORM. THE BEST ENHANCEMENT WILL BE NORTH AND WEST OF A DISTURBANCE CIRCULATING OVER KCOS. PRECIPITATION ENHANCED BY THAT DISTURBANCE WILL MOVE OVER KASE THROUGH EARLY THIS EVENING...PROVIDING THE FURTHER DEGRADATION OF FLIGHT CONDITIONS THERE. EXPECT MVFR CIGS AND VSBYS OVER KASE UNTIL ABOUT 06Z AND INTERMITTENT IFR IN STRONGER SNOW SHOWERS THROUGH ABOUT 02Z. KEGE...KRIL SHOULD SEE BRIEF MVFR CIGS AND VSBYS THRU ABOUT 04Z AS SNOW SHOWERS ROTATE OVER THOSE LOCATIONS. KGJT...KVEL AND ALL AIRPORTS NORTH OF I-70 SHOULD REMAIN VFR. THE NORTHERN EDGE OF THE MAIN PRECIP BAND WILL EXTEND FROM KFNL THEN SOUTHWEST TO KCNY. THE HEAVIEST PRECIP IN THE BAND SHOULD EXTEND FROM KASE TO KMTJ TO ABOUT KBDG. MOUNTAINS AND HIGH PASSES ACROSS CENTRAL CO AND SE UT WILL REMAIN OBSCURED TONIGHT AND BEGIN OPENING UP AFTER SUNRISE. CONDITIONS WILL IMPROVE SIGNIFICANTLY AFTER ABOUT 08Z TONIGHT. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ018. WINTER STORM WARNING UNTIL 6 PM MST THIS EVENING FOR COZ021. WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ019. UT...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR UTZ028. && $$ SHORT TERM...NL LONG TERM...NL AVIATION...CC
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1254 PM MST THU JAN 1 2015 .UPDATE... ISSUED AT 1254 PM MST THU JAN 1 2015 BAND OF SNOW MOVING ACROSS THE PALMER DIVIDE IS PRODUCING A PERIOD OF HEAVY SNOW. IT IS ALSO MAKING A FASTER NORTHWARD PROGRESSION. AS A RESULT OF THE HEAVIER INTENSITY..SHOULD HAVE A BETTER CHANCE OF MAKING IT INTO THE DENVER METRO AREA THIS AFTERNOON SO HAVE BOOSTED POPS ACCORDINGLY. UPDATE ISSUED AT 1012 AM MST THU JAN 1 2015 SATELLITE SHOWS THE MID LEVEL CLOUD DECK SPREADING INTO THE SOUTHERN PORTIONS OF THE FORECAST AREA. RADAR ECHOES ARE RAPIDLY INCREASING IN COVERAGE JUST TO THE SOUTH OF THE FORECAST AREA IN SOUTHERN COLORADO...BUT MOST OF THIS IS VIRGA ON THE PLAINS. MEANWHILE...MOUNTAIN LOCALES IN SOUTHERN COLORADO ARE RECEIVING ACCUMULATING SNOWFALL. Q-G LIFT WILL INCREASE THROUGH THE AFTERNOON UNDER THE LARGE SCALE DEFORMATION ZONE SETTING UP ACROSS OUR FORECAST AREA. AS A RESULT...THE CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH VIRGA BECOMING WIDESPREAD. QUESTION STILL SURROUNDS HOW EFFICIENTLY THE SUBCLOUD LAYER WILL MOISTEN ESPECIALLY SINCE THERE IS STILL SOME LOW LEVEL DOWNSLOPE COMPONENT BELOW 700 MB. ABOVE THAT...FAIRLY STRONG EASTERLY UPSLOPE COMPONENT AROUND 20 KNOTS ON AVERAGE. DUE TO THE DRIER LOW LEVEL AIR...THE MAIN THREAT OF ACCUMULATING SNOW STILL RESIDES FROM PARK/SUMMIT COUNTIES EASTWARD INTO DOUGLAS COUNTY AND THE PALMER DIVIDE AREA LATER THIS AFTERNOON. HOWEVER...BY LATER THIS EVENING THE BEST LIFT SHIFTS SLOWLY NORTHWARD SO BETTER CHANCE COULD ACTUALLY MOVE SOMEWHAT NORTH. WILL HAVE TO WATCH THIS FOR DUSTING TO 1 INCH OF SNOW POSSIBLE OVER THE DENVER METRO AREA MAINLY BETWEEN 4 PM AND MIDNIGHT. ALL OF THIS HANDLED WELL IN EXISTING FORECAST SO ONLY ADJUSTMENTS WERE TO INCREASE PARK COUNTY POPS AS EVEN VALLEY LOCATIONS IN SOUTH PARK SHOULD PICK UP MEASURABLE SNOWFALL THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 425 AM MST THU JAN 1 2015 A CLOSED MID-UPPER LOW OVER NORTH CENTRAL ARIZONA AT 09Z WILL BECOME INCREASINGLY ELONGATED ACROSS COLORADO AS IT SHIFTS EASTWARD ACROSS THE FOUR CORNERS REGION TODAY. AT THE SFC...AN EXPANSIVE AREA OF HIGH PRESSURE LINKED TO AN ARCTIC AIRMASS COVERS THE GREAT PLAINS. MODELS SHOW PRECIP FORMING NORTHEASTWARD ALONG THE 700-500MB TROUGH DEFORMATION AXIS REACHING THE SOUTHWEST CORNER OF THE FORECAST AREA BY LATE THIS MORNING. FORWARD SPEED OF CLOUD SHIELD WRAPPING AROUND THE UPPER LOW WILL LIKELY ARRIVE SOONER THAN THAT BASED ON SPEED OF MOTION MEASUREMENTS USING IR SATELLITE IMAGERY. EXCEPT FOR A BAND OF CIRRUS CLOUD STREAKING NEWRD ACRS THE SOUTHEAST CORNER OF THE CWA...SKIES AT THE PRESENT TIME WERE CLEAR ACROSS N-CENTRAL/NORTHEAST COLORADO. HRRR AND RAP MDLS SHOW LIGHT SNOWFALL/QPF OVER THE MOSQUITO...TEN MILE AND SOUTHERN FRONT RANGE MTNS BY MIDDAY...THEN SPREADING NORTHWARD OVER THE FRONT RANGE AND EASTWARD ALONG THE PALMER DIVIDE AND SOUTHERN SECTIONS OF THE I-25 URBAN CORRIDOR DURING THE LATE AFTERNOON HOURS. FORECASTED PCPN AMTS IN THIS AREA RANGE FROM A TRACE TO 0.20 INCH BY 00Z/FRI...AND SNOW AMOUNTS FROM A TRACE TO 3 INCHES. THE HEAVIER AMTS WILL BE FOUND OVER THE HIGHER TERRAIN SURROUNDING SOUTH PARK AND ALONG HIGHER PORTIONS OF THE PALMER DIVIDE IN DOUGLAS COUNTY. BY EVENING WITH THE UPPER LOW WEAKENING AND TURNING SOUTHEAST AWAY FROM COLORADO... SHOULD SEE A MARKED DECREASE IN SNOWFALL ACROSS SOUTHERN SECTIONS OF THE CWA BY MID TO LATE EVENING. AS THIS IS TAKING PLACE...MODELS NAMELY THE NAM...SHOW A SECONDARY AREA OF SNOWFALL DEVELOPING OVER THE NORTHERN FRONT RANGE MTN AND NRN I-25 URBAN CORRIDOR AS A RESULT OF OROGRAPHIC LIFT AND COLD ADVECTION OCCURRING ON THE NORTHERN FRINGE OF THE UPPER TROUGH. COULD SEE LOCAL SNOW AMTS UP TO AN INCH OR SO OVER HIGHER ELEVATIONS OF THE NRN FRONT RANGE AND POSSIBLY A QUARTER INCH OR SO ON THE NEARBY PLAINS BEFORE SKIES CLEAR AROUND 10Z/FRI. HIGH TEMPERATURES TODAY ARE EXPECTED TO BE A FEW DEGS COOLER THAN YESTERDAY DUE IN LARGE PART TO THE LACK OF SUNSHINE THIS AFTERNOON. WHEREAS TEMPS TONIGHT NOT AS COLD AS PREVIOUS NIGHTS BECAUSE OF CLOUD COVER AND AS A RESULT OF MIXED BNDRY LAYER DUE TO PCPN IN THE AREA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 425 AM MST THU JAN 1 2015 THE UPPER LOW NOW OVER ARIZONA WILL WEAKEN AND BECOME ELONGATED ACROSS COLORADO EARLY FRIDAY MORNING. A PIECE OF THIS LOW SEPARATES FROM THE PARENT SYSTEM WHICH WILL REMAIN OVER NEW MEXICO THROUGH FRIDAY NIGHT. STILL EXPECT A FAIR AMOUNT OF CLOUDINESS FRIDAY AM BUT ANY PRECIP WILL HAVE FINISHED DURING THE EARLY MORNING HOURS. TEMPERATURES WILL STILL REMAIN IN THE 30S ACROSS LOWER ELEVATIONS. THE MAIN LOW OVER NEW MEXICO IS PROGGED TO LIFT NORTHEAST INTO THE CENTRAL PLAINS ON SATURDAY WHILE A SECONDARY WAVE MOVES RAPIDLY SOUTHEAST FROM THE NORTHERN ROCKIES. AN ACCOMPANIED COLD FRONT EXPECTED TO BLAST ACROSS THE NORTHEAST PLAINS AROUND MIDDAY SATURDAY WITH A BRIEF PERIOD OF UPSLOPE FLOW ON SATURDAY AFTERNOON AND QUICK SHOT OF QG UPWARD FORCING AS STRONG JET MOVES ACROSS COLORADO. WILL CONTINUE TO INCREASE POPS SLIGHTLY DURING THIS PERIOD AS CONDITIONS CONTINUE TO LOOK MORE FAVORABLE FOR A SHOT OF SNOW OVER MOUNTAINS AND PLAINS. FOR SUNDAY AND INTO EARLY NEXT WEEK....THE PATTERN WILL SHIFT TO A STRONG NORTHWEST FLOW ALOFT. THIS WILL RESULT IN INCREASING WINDS OVER MOUNTAINS AND EAST SLOPES WITH A DOWNSLOPE WARMING TREND OVER THE NORTHEAST PLAINS. GIVEN THE FLOW PATTERN EXPECT SOME SNOW SHOWERS TO CONTINUE OVER THE HIGHER ELEVATIONS OF THE NORTHERN MOUNTAINS BUT ONLY MINIMAL ACCUMULATIONS. && .AVIATION...(FOR THE TAFS THROUGH 18Z FRIDAY MORNING) ISSUED AT 1254 PM MST THU JAN 1 2015 CLOUDS WILL CONTINUE TO THICKEN AND LOWER THROUGH 21Z-03Z WITH ILS LANDING CONDITIONS LIKELY WITH CEILINGS UNDER 5000-6000 FEET. SHOULD ALSO SEE AREAS OF MVFR CEILINGS AND 3-4SM VISIBILITIES IN LIGHT SNOW 21Z-07Z. LOCAL VISIBILITY AROUND 1SM WITH AROUND 1 INCH ACCUMULATION POSSIBLE AT KAPA GIVEN INTENSITY OF SNOW BAND MOVING UP FROM THE SOUTH. AFT 07Z...AREAS OF LIGHT SNOW AND LOWER CEILINGS ARE EXPECTED TO DISSIPATE THRU 12Z AS AIRMASS GRADUALLY DRIES AND UPPER LEVEL DISTURBANCE DEPARTS TO THE NORTHEAST. LIGHT SOUTH/SOUTHWEST WINDS UNDER 7 KNOTS MAY BECOME LIGHT/VARIABLE THROUGH THE EARLY EVENING BEFORE SETTLING TO A SOUTHWEST/WEST AROUND 5-8 KNOTS OVERNIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARJENBRUCH SHORT TERM...BAKER LONG TERM...ENTREKIN AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1012 AM MST THU JAN 1 2015 .UPDATE... ISSUED AT 1012 AM MST THU JAN 1 2015 SATELLITE SHOWS THE MID LEVEL CLOUD DECK SPREADING INTO THE SOUTHERN PORTIONS OF THE FORECAST AREA. RADAR ECHOES ARE RAPIDLY INCREASING IN COVERAGE JUST TO THE SOUTH OF THE FORECAST AREA IN SOUTHERN COLORADO...BUT MOST OF THIS IS VIRGA ON THE PLAINS. MEANWHILE...MOUNTAIN LOCALES IN SOUTHERN COLORADO ARE RECEIVING ACCUMULATING SNOWFALL. Q-G LIFT WILL INCREASE THROUGH THE AFTERNOON UNDER THE LARGE SCALE DEFORMATION ZONE SETTING UP ACROSS OUR FORECAST AREA. AS A RESULT...THE CLOUDS WILL CONTINUE TO THICKEN AND LOWER WITH VIRGA BECOMING WIDESPREAD. QUESTION STILL SURROUNDS HOW EFFICIENTLY THE SUBCLOUD LAYER WILL MOISTEN ESPECIALLY SINCE THERE IS STILL SOME LOW LEVEL DOWNSLOPE COMPONENT BELOW 700 MB. ABOVE THAT...FAIRLY STRONG EASTERLY UPSLOPE COMPONENT AROUND 20 KNOTS ON AVERAGE. DUE TO THE DRIER LOW LEVEL AIR...THE MAIN THREAT OF ACCUMULATING SNOW STILL RESIDES FROM PARK/SUMMIT COUNTIES EASTWARD INTO DOUGLAS COUNTY AND THE PALMER DIVIDE AREA LATER THIS AFTERNOON. HOWEVER...BY LATER THIS EVENING THE BEST LIFT SHIFTS SLOWLY NORTHWARD SO BETTER CHANCE COULD ACTUALLY MOVE SOMEWHAT NORTH. WILL HAVE TO WATCH THIS FOR DUSTING TO 1 INCH OF SNOW POSSIBLE OVER THE DENVER METRO AREA MAINLY BETWEEN 4 PM AND MIDNIGHT. ALL OF THIS HANDLED WELL IN EXISTING FORECAST SO ONLY ADJUSTMENTS WERE TO INCREASE PARK COUNTY POPS AS EVEN VALLEY LOCATIONS IN SOUTH PARK SHOULD PICK UP MEASURABLE SNOWFALL THIS AFTERNOON. && .SHORT TERM...(TODAY THROUGH TONIGHT ) ISSUED AT 425 AM MST THU JAN 1 2015 A CLOSED MID-UPPER LOW OVER NORTH CENTRAL ARIZONA AT 09Z WILL BECOME INCREASINGLY ELONGATED ACROSS COLORADO AS IT SHIFTS EASTWARD ACROSS THE FOUR CORNERS REGION TODAY. AT THE SFC...AN EXPANSIVE AREA OF HIGH PRESSURE LINKED TO AN ARCTIC AIRMASS COVERS THE GREAT PLAINS. MODELS SHOW PRECIP FORMING NORTHEASTWARD ALONG THE 700-500MB TROUGH DEFORMATION AXIS REACHING THE SOUTHWEST CORNER OF THE FORECAST AREA BY LATE THIS MORNING. FORWARD SPEED OF CLOUD SHIELD WRAPPING AROUND THE UPPER LOW WILL LIKELY ARRIVE SOONER THAN THAT BASED ON SPEED OF MOTION MEASUREMENTS USING IR SATELLITE IMAGERY. EXCEPT FOR A BAND OF CIRRUS CLOUD STREAKING NEWRD ACRS THE SOUTHEAST CORNER OF THE CWA...SKIES AT THE PRESENT TIME WERE CLEAR ACROSS N-CENTRAL/NORTHEAST COLORADO. HRRR AND RAP MDLS SHOW LIGHT SNOWFALL/QPF OVER THE MOSQUITO...TEN MILE AND SOUTHERN FRONT RANGE MTNS BY MIDDAY...THEN SPREADING NORTHWARD OVER THE FRONT RANGE AND EASTWARD ALONG THE PALMER DIVIDE AND SOUTHERN SECTIONS OF THE I-25 URBAN CORRIDOR DURING THE LATE AFTERNOON HOURS. FORECASTED PCPN AMTS IN THIS AREA RANGE FROM A TRACE TO 0.20 INCH BY 00Z/FRI...AND SNOW AMOUNTS FROM A TRACE TO 3 INCHES. THE HEAVIER AMTS WILL BE FOUND OVER THE HIGHER TERRAIN SURROUNDING SOUTH PARK AND ALONG HIGHER PORTIONS OF THE PALMER DIVIDE IN DOUGLAS COUNTY. BY EVENING WITH THE UPPER LOW WEAKENING AND TURNING SOUTHEAST AWAY FROM COLORADO... SHOULD SEE A MARKED DECREASE IN SNOWFALL ACROSS SOUTHERN SECTIONS OF THE CWA BY MID TO LATE EVENING. AS THIS IS TAKING PLACE...MODELS NAMELY THE NAM...SHOW A SECONDARY AREA OF SNOWFALL DEVELOPING OVER THE NORTHERN FRONT RANGE MTN AND NRN I-25 URBAN CORRIDOR AS A RESULT OF OROGRAPHIC LIFT AND COLD ADVECTION OCCURRING ON THE NORTHERN FRINGE OF THE UPPER TROUGH. COULD SEE LOCAL SNOW AMTS UP TO AN INCH OR SO OVER HIGHER ELEVATIONS OF THE NRN FRONT RANGE AND POSSIBLY A QUARTER INCH OR SO ON THE NEARBY PLAINS BEFORE SKIES CLEAR AROUND 10Z/FRI. HIGH TEMPERATURES TODAY ARE EXPECTED TO BE A FEW DEGS COOLER THAN YESTERDAY DUE IN LARGE PART TO THE LACK OF SUNSHINE THIS AFTERNOON. WHEREAS TEMPS TONIGHT NOT AS COLD AS PREVIOUS NIGHTS BECAUSE OF CLOUD COVER AND AS A RESULT OF MIXED BNDRY LAYER DUE TO PCPN IN THE AREA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 425 AM MST THU JAN 1 2015 THE UPPER LOW NOW OVER ARIZONA WILL WEAKEN AND BECOME ELONGATED ACROSS COLORADO EARLY FRIDAY MORNING. A PIECE OF THIS LOW SEPARATES FROM THE PARENT SYSTEM WHICH WILL REMAIN OVER NEW MEXICO THROUGH FRIDAY NIGHT. STILL EXPECT A FAIR AMOUNT OF CLOUDINESS FRIDAY AM BUT ANY PRECIP WILL HAVE FINISHED DURING THE EARLY MORNING HOURS. TEMPERATURES WILL STILL REMAIN IN THE 30S ACROSS LOWER ELEVATIONS. THE MAIN LOW OVER NEW MEXICO IS PROGGED TO LIFT NORTHEAST INTO THE CENTRAL PLAINS ON SATURDAY WHILE A SECONDARY WAVE MOVES RAPIDLY SOUTHEAST FROM THE NORTHERN ROCKIES. AN ACCOMPANIED COLD FRONT EXPECTED TO BLAST ACROSS THE NORTHEAST PLAINS AROUND MIDDAY SATURDAY WITH A BRIEF PERIOD OF UPSLOPE FLOW ON SATURDAY AFTERNOON AND QUICK SHOT OF QG UPWARD FORCING AS STRONG JET MOVES ACROSS COLORADO. WILL CONTINUE TO INCREASE POPS SLIGHTLY DURING THIS PERIOD AS CONDITIONS CONTINUE TO LOOK MORE FAVORABLE FOR A SHOT OF SNOW OVER MOUNTAINS AND PLAINS. FOR SUNDAY AND INTO EARLY NEXT WEEK....THE PATTERN WILL SHIFT TO A STRONG NORTHWEST FLOW ALOFT. THIS WILL RESULT IN INCREASING WINDS OVER MOUNTAINS AND EAST SLOPES WITH A DOWNSLOPE WARMING TREND OVER THE NORTHEAST PLAINS. GIVEN THE FLOW PATTERN EXPECT SOME SNOW SHOWERS TO CONTINUE OVER THE HIGHER ELEVATIONS OF THE NORTHERN MOUNTAINS BUT ONLY MINIMAL ACCUMULATIONS. && .AVIATION...(FOR THE TAFS THROUGH 18Z FRIDAY MORNING) ISSUED AT 1012 AM MST THU JAN 1 2015 CLOUDS WILL CONTINUE TO THICKEN AND LOWER THROUGH 22Z-03Z WITH ILS LANDING CONDITIONS LIKELY WITH CEILINGS UNDER 5000-6000 FEET. SHOULD ALSO SEE POCKETS OF MVFR CEILINGS AND 3-4SM VISIBILITIES IN LIGHT SNOW 22Z-07Z. AFT 07Z...AREAS OF LIGHT SNOW AND LOWER CEILINGS ARE EXPECTED TO DISSIPATE THRU 12Z AS AIRMASS GRADUALLY DRIES AND UPPER LEVEL DISTURBANCE DEPARTS TO THE NORTHEAST. LIGHT SOUTH/SOUTHWEST WINDS UNDER 7 KNOTS MAY BECOME LIGHT/VARIABLE THROUGH THE EARLY EVENING BEFORE SETTLING TO A SOUTHWEST/WEST AROUND 5-8 KNOTS OVERNIGHT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...BARJENBRUCH SHORT TERM...BAKER LONG TERM...ENTREKIN AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MIAMI FL
124 PM EST THU JAN 1 2015 .AVIATION... LINGERING STATIONARY FRONT ACROSS THE AREA IS EXPECTED TO PUSH TO THE NORTH AS A WARM FRONT THROUGH THE NIGHT. THIS WILL LEAVE AMPLE LOW LEVEL MOISTURE AND THE THREAT OF FOG/LOW CIGS MAINLY ACROSS THE GULF COAST OVERNIGHT AND INTO EARLY FRIDAY MORNING. UNDERCUT LAMP GUIDANCE AGAIN FOR KAPF THROUGH THE NIGHT PREVAILING MVFR CIGS WITH TEMPO IFR CIGS AND VSBY. BELIEVE THAT THE EAST COAST SITES SHOULD REMAIN VFR WITH BRIEF MVFR CIGS POSSIBLE BUT NOT CONFIDENT ENOUGH TO MENTION IN TAFS ATTM. && .PREV DISCUSSION... /ISSUED 1004 AM EST THU JAN 1 2015/ UPDATE... SCATTERED SHOWERS REMAIN THIS MORNING MAINLY ACROSS THE ATLANTIC WATERS OFF THE PALM BEACHES. WEAK STATIONARY FRONT REMAINS DRAPED ACROSS THE AREA THIS MORNING CONTRIBUTING TO THE SHOWERS AND EXTENSIVE CLOUDINESS. LATEST VISIBLE SATELLITE DOES HOWEVER SHOW CLOUD SHIELD BEGINNING TO ERODE ACROSS BROWARD AND MIAMI-DADE COUNTIES LATE THIS MORNING. THIS HAS ALLOWED TEMPERATURES TO SURGE INTO THE MID TO UPPER 70S ALREADY. HRRR CONTINUES TO DEPICT ISOLATED LIGHT SHOWERS ACROSS MAINLY THE EASTERN HALF OF THE AREA INTO THE EARLY AFTERNOON HOURS...SO KEPT SLIGHT CHANCE POP GOING. THE REMAINDER OF THE FORECAST LOOKS ON TRACK AT THIS TIME. UPDATE SENT. PREV DISCUSSION... /ISSUED 319 AM EST THU JAN 1 2015/ DISCUSSION... A COMPACT AND WEAK MESOSCALE LOW PASSED SOUTHWARD ACROSS THE ATLANTIC WATERS YESTERDAY ALONG PALM BEACH COUNTY THEN DRIFTED WESTWARD ACROSS THE SOUTH FLORIDA PENINSULA EARLY THIS MORNING. DURING THE EARLY MORNING HOURS SCATTERED SHOWER ACTIVITY OCCURRED WITH THE GREATEST COVERAGE ACROSS NORTHERN BROWARD COUNTY AND ACROSS PALM BEACH COUNTY AND ADJACENT ATLANTIC WATERS...WITH THIS COVERAGE CONTINUING. THE COMBINATION OF LOW STRATUS AND/OR FOG WILL CONTINUE EARLY THIS MORNING WITH MOST OF THE COVERAGE EXPECTED ACROSS MIAMI DADE COUNTY AND SOUTHERN HALF OF BROWARD COUNTY. THE WILL BE A CHANCE OF RIP CURRENTS TODAY BUT MAINLY EXPECTED ACROSS THE PALM BEACH COUNTY BEACHES. THE LATEST MODEL GUIDANCE INDICATES A WEAK SURFACE TROUGH AND DIFFUSE FRONTAL BOUNDARY CONTINUING ACROSS THE SOUTH FLORIDA PENINSULA TODAY WITH HIGH PRESSURE THEN STARTING TO BUILD BACK ACROSS THE REGION THIS EVENING AND OVER NIGHT. THE FORECAST FOR TODAY IS FOR ISOLATED TO SCATTERED SHOWERS MAINLY ACROSS THE ATLANTIC WATERS AND THE ATLANTIC METRO AREAS WITH THE GREATEST COVERAGE CONTINUING TO BE ACROSS BROWARD AND PALM BEACH COUNTIES AND THE ADJACENT ATLANTIC WATERS. A DRYING TREND IS THEN FORECAST WITH THE MODEL CONSENSUS INDICATING SOUTHERLY LOW LEVEL FLOW BRINGING IN DRIER AIR INTO THE REGION TONIGHT INTO FRIDAY. BY FRIDAY HIGH PRESSURE WILL PREVAIL ACROSS THE REGION WITH A SURFACE RIDGE EAST OF THE FLORIDA PENINSULA AND AT THE MID TO UPPER LEVELS A LARGE AMPLITUDE RIDGE BECOMING ESTABLISHED ACROSS THE FLORIDA STRAITS. THIS PATTERN WILL MORE OR LESS PERSIST THROUGH THE UPCOMING WEEKEND...WITH STABLE WEATHER CONDITIONS AND INCREASINGLY WARMER TEMPERATURES PREVAILING ACROSS THE REGION. FOR THE EXTENDED FORECAST...THE GLOBAL MODEL CONSENSUS INDICATES THE NEXT COLD FRONT ENTERING THE FLORIDA PANHANDLE AND NORTHERN FLORIDA ON SUNDAY AND THEN INTO CENTRAL FLORIDA ON MONDAY AND APPROACHING LAKE OKEECHOBEE AND WEAKENING MONDAY NIGHT. BY TUESDAY THE MODELS START TO DIVERGE IN THEIR SOLUTIONS...BUT OVER ALL NO SIGNIFICANT IMPACTS ARE FORECAST THUS FAR FOR SOUTH FLORIDA WITH THE FORECAST INDICATING JUST A GRADUAL COOL DOWN AND POSSIBLY SOME ISOLATED SHOWER ACTIVITY. /BD MARINE... THE LOCAL PRESSURE GRADIENT ACROSS THE REGION EARLY THIS MORNING IS SUCH THAT WINDS IN THE 15 TO 20 KNOT RANGE ARE FORECAST ACROSS THE ATLANTIC WATERS MAINLY TO THE EAST OF PALM BEACH COUNTY AND ACROSS THE OFF SHORE WATERS...WITH AN SCEC FOR THESE WATERS TODAY. THE PRESSURE GRADIENT AND RESULTANT WINDS EAST OF PALM BEACH COUNTY IS FORECAST TO RELAX TONIGHT INTO FRIDAY. FOR THE REMAINDER OF THE OF THE FORECAST...WINDS AND SEAS ACROSS THE GULF AND ATLANTIC WATERS ARE FORECAST TO REMAIN WELL BELOW ADVISORY LEVELS. /BD && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 70 81 73 82 / 10 10 10 10 FORT LAUDERDALE 72 81 73 81 / 10 10 10 10 MIAMI 71 81 73 83 / 10 10 10 10 NAPLES 67 81 68 82 / 10 10 10 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM...60/BD LONG TERM....60/BD AVIATION...10/CD
AREA FORECAST DISCUSSION
NWS POCATELLO ID
201 PM MST THU JAN 1 2015 .SHORT TERM...TONIGHT THROUGH SUNDAY. THE LATEST SATELLITE IMAGERY WAS CLEARLY SHOWING A BROAD AREA OF STRATUS/LOW CLOUDS EXTENDING FROM BOISE UP THE VALLEY THROUGH POCATELLO. NUMERICAL MODELS SHOW THE STRATUS WORKING FURTHER NE TONIGHT AND LINGERING THROUGH A GOOD PORTION OF THE MORNING FRIDAY BEFORE GRADUALLY DISSIPATING AHEAD OF AN INCOMING SYSTEM. FURTHER UPSTREAM...A VIGOROUS PAC STORM SYSTEM WAS SPREADING INTO THE NW BRITISH COLUMBIA COAST. THE MODELS SHEAR THIS WAVE SE ACROSS THE CANADIAN ROCKIES TONIGHT/FRIDAY AND ALONG THE MONTANA/WYOMING DIVIDE FRIDAY NIGHT/SATURDAY WITH ATTENDING SNOWFALL IMPACTING MAINLY THE NE MOUNTAINS. STORM TOTAL ACCUMULATIONS OF 1 TO 4 INCHES ARE ANTICIPATED FRIDAY NIGHT/SATURDAY IN THE MOUNTAINS FROM ISLAND PARK SOUTH THROUGH SODA SPRINGS. SOME EROSION OF THE COLD AIR TRAPPED IN THE VALLEYS IS ALSO ANTICIPATED LATE FRIDAY AFTERNOON/SATURDAY. A SECOND STRONGER SYSTEM HITS THE NW BRITISH COLUMBIA COAST SUNDAY WHILE THE ASSOCIATED PRECIPITATION BEGINS TO SPREAD INTO THE NRN AND ERN MOUNTAINS AS EARLY AS SATURDAY NIGHT AND CONTINUES THROUGH SUNDAY AND MONDAY. CONTINUED WARMING IS EXPECTED SUNDAY AS SW WINDS BEGIN TO SCOUR OUT THE REMAINING COLD AIR TRAPPED IN THE VALLEYS. HUSTON .LONG TERM...SUNDAY NIGHT THROUGH NEXT THURSDAY NIGHT. ONLY ONE SIGNIFICANT TROUGH PASSING THROUGH EARLY DURING THE EXTENDED PERIOD. EXPECTED TO MAINLY AFFECT THE MOUNTAINS WITH A MODERATE AMOUNT OF SNOW...WHILE THE LOWER ELEVATIONS WILL SEE EITHER RAIN OR SNOW WITH ONLY LIGHT ACCUMULATION. THIS WILL MAINLY BE SUN NIGHT AND MON. AFTER THIS...AN UPPER LEVEL HIGH MOVES IN FROM THE SOUTH...KEEPING MILD AIR AND LOWER ELEVATION TEMPERATURES IN AT LEAST THE UPPER 30S. AT THE VERY END...CLOUDS START TO OVERSPREAD AGAIN FROM THE WEST AS ANOTHER LOW ENTERS THE NORTH AMERICAN WEST COAST. GFS IS TENDING TO BE THE DRIER GUIDANCE COMPARED TO ECMWF. THE ECMWF IS ALSO MUCH WARMER WITH HIGHER 500MB HEIGHTS AND THUS WARMER AIRMASS. HAVE SIDED A LITTLE MORE TOWARDS THE GFS...ESPECIALLY FOR OVERNIGHT LOWS. MESSICK && .AVIATION...STRATUS AND FOG COULD...AND SHOULD...BE A PROBLEM AGAIN TONIGHT. BUT IT IS A LOW CONFIDENCE FORECAST BASED ON SEVERAL ISSUES. THE PRESSURE GRADIENT ACROSS THE EASTERN MAGIC VALLEY AND SNAKE RIVER PLAIN WILL INFLUENCE WIND TO BE WESTERLY...WHILE THE NATURAL SLOPE-VALLEY EFFECT WOULD BE THE OPPOSITE. THE SPREAD OF STRATUS BACK OVER THE THREE VALLEY AIRDROMES IS COMPLETELY DEPENDENT ON THE WIND FLOW. HRRR FORECAST INDICATES NORTHEAST TO EAST GRADIENT DEVELOPS AND KEEPS THE STRATUS AWAY FROM THE LOW ELEVATION AIRPORTS. BOUNDARY LAYER MOISTURE PROGS AND STATISTICS INDICATE THE STRATUS SHOULD RECUR...PLUS THE STRATUS HAS IN NO WAY TOTALLY EVAPORATED. THUS HAVE HAD IT REDEVELOP AND BE EVEN LOWER THAN IT WAS LAST NIGHT. MEANWHILE...AT KSUN THE STRATUS DID ADVECT UP THE VALLEY WITH THE ONSET OF SOUTHEAST WIND...BUT IT PULLED UP SHORT AND THINNED WITH THE DIURNAL WARMING. FEEL MORE CONFIDENT ABOUT THIS ONE THAT THE FOG WILL STAY AWAY AT LEAST THROUGH THE LATE NIGHT AND MORNING HOURS OF THE TAF. NO SIGNIFICANT WINDSPEEDS EXPECTED. MESSICK && .PIH WATCHES/WARNINGS/ADVISORIES...NONE. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
555 PM EST THU JAN 1 2015 .SYNOPSIS... AN ARCTIC FRONT WILL SWEEP NORTHWEST TO SOUTHEAST THROUGH THE REGION LATE TONIGHT INTO FRIDAY. HIGH PRESSURE WILL BUILD ACROSS THE REGION FRIDAY NIGHT THROUGH SATURDAY. LOW PRESSURE TRACKING NORTHWEST OF MAINE WILL ALLOW A WARM FRONT TO APPROACH THE REGION SUNDAY. && .NEAR TERM /THROUGH FRIDAY/... 530 PM UPDATE: MOST OF THIS UPDATE WAS MADE ON REFINING POPS BASED ON FCST LIQ EQUIV POPS ACROSS THE NW TWO THIRDS OF THE FA. THIS WAS DONE USING THE LATEST HRLY UPDATED HRRR SIM RADAR REF OUTPUT...WHICH SHOWS MOST OF THE SN SHWR ACTIVITY XPCTD OVR THE NW AND FAR NRN PTNS OF THE FA THIS EVE...WITH THIS BAND SLOWLY MOVG SE LATE TNGT INTO NE PTNS OF THE FA...BEFORE BECOMING LESS ORGANIZED BY DAYBREAK FRI. WITH THE ACTUAL ARCTIC FRONT XPCTD TO REMAIN NW OF THE WRN ME/QB BORDER MSLY PRIOR TO 06Z...MOST OF THE INITIAL SN SHWR ACTIVITY WILL BE FRONTOGENETICALLY FORCED...WITH ANY LCLY ENHANCED BANDING OF SN RATES MSLY AFT 06Z ALG THE LEADING EDGE OF THE ARCTIC FRONT AS IT CROSSES THRU NW AND EVENTUALLY NE ME VERY LATE TNGT. NOT SURE WHETHER THIS BANDING WILL BE INTENSE ENOUGH TO QUALIFY AS SN SQLS DURG THIS TM OF NGT WHEN SFC-1000M LAPSE RATES ARE MORE STABLE THAN LATE MORN INTO AFTN...BUT CANNOT COMPLETELY RULE SN SQL ACTIVITY ATTM. OTHERWISE...MODIFICATIONS WERE MADE TO CLD CVR AND FCST HRLY TEMPS OVRNGT INTO FRI BASED ON 5 PM SAT IMAGERY AND SFC OBS. ORGNL DISC: MAIN CONCERN OVERNIGHT CONTINUES TO BE THE POTENTIAL FOR SNOW SQUALLS LATE MSLY ACROSS NW AND FAR N PTNS OF THE FA. LOW PRESSURE CURRENTLY CROSSING HUDSON BAY WILL CONTINUE ITS EASTWARD TREK TONIGHT, DRAGGING ITS ATTENDANT COLD FRONT ALONG SOUTHERN CANADA/NORTHERN UNITED STATES AS IT DOES SO. THIS FRONT WILL PUSH INTO NORTHERN MAINE LATE THIS EVENING AND EVENTUALLY MOVE OFF THE MAINE COAST FRIDAY MORNING. THIS IS A POTENT ARCTIC FRONT AND WILL SERVE TO DO TWO THINGS. ONE, IT WILL RETURN COLDER AIR TO THE REGION, AND TWO, IT WILL ALSO SERVE AS A FOCUS FOR SNOW SHOWER ACTIVITY, ESPECIALLY OVER NORTHERN MAINE. GOOD MOISTURE CONVERGENCE ALONG THE FRONT, ALONG WITH STEEPENING LAPSE RATES AND PLENTIFUL LIFT, A BAND OF SNOW SQUALLS WILL BE POSSIBLE, ESPECIALLY OVER THE SAINT JOHN VALLEY. ANY SQUALLS WILL BE CAPABLE OF PRODUCING VISIBILITY OF A HALF MILE OR LESS, GUSTY WINDS, AND A QUICK INCH OR TWO OF SNOW. OUTSIDE OF ANY SQUALLS, EXPECT JUST SCATTERED SNOW SHOWERS WITH LIGHT ACCUMULATION. TEMPERATURES WILL DROP OFF QUICKLY BEHIND THE FRONT, WITH OVERNIGHT LOWS RETURNING INTO THE SINGLE DIGITS ACROSS THE NORTHERN PORTIONS OF THE COUNTY. ELSEWHERE, TEMPERATURES WILL BE IN THE TEENS TO MID 20S. FOR FRIDAY...THE AFOREMENTIONED FRONT WILL FINISH ITS SOUTHWARD PUSH AND WILL BE OFFSHORE BY AFTERNOON. AS SUCH, THE BULK OF THE SNOW SHOWERS WILL COME TO AN END WITH JUST A FEW LINGERING SNOW FLAKES POSSIBLE OVER NORTHERN MAINE. HIGHS WILL BE CHILLY IN THE NORTH...10 TO 15 DEGREES...BUT CENTRAL AND SOUTHERN MAINE WILL BE A BIT BETTER, TOPPING OUT IN THE 20S TO AROUND 30. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... COULD HAVE A SLIGHT CHANCE OF SNOW SHOWERS ACROSS THE NORTH/MOUNTAINS EARLY FRIDAY NIGHT. OTHERWISE...HIGH PRESSURE BUILDS EAST TOWARD THE REGION FRIDAY NIGHT WITH DECREASING CLOUDS NORTH AND MOSTLY CLEAR SKIES DOWNEAST. HIGH PRESSURE THEN CROSSES THE REGION SATURDAY WITH PARTLY/MOSTLY SUNNY SKIES. LOW PRESSURE LIFTING ACROSS THE GREAT LAKES WILL DRAW A WARM FRONT TOWARD NEW ENGLAND SATURDAY NIGHT. CLOUD COVER WILL INCREASE ACROSS THE REGION EARLY SATURDAY NIGHT. LOW TEMPERATURES SATURDAY NIGHT WILL OCCUR EARLY THEN BEGIN TO RISE OVERNIGHT WITH THE INCREASING CLOUDS. OVERRUNNING PRECIPITATION WILL THEN EXPAND ACROSS THE FORECAST AREA LATER SATURDAY NIGHT. BASED ON CRITICAL THICKNESSES...EXPECT PRECIPITATION TO REMAIN MOSTLY IN THE FORM OF SNOW ACROSS THE FORECAST AREA SATURDAY NIGHT. HOWEVER...THE SNOW COULD BEGIN TO TRANSITION TO A WINTRY MIX ACROSS DOWNEAST AREAS LATE. THE PRIMARY GREAT LAKES LOW TRACKS NORTHWEST OF THE REGION SUNDAY DRAWING THE WARM FRONT NORTH ACROSS THE REGION. MODELS INDICATE THE POSSIBILITY THAT A WEAK SECONDARY LOW COULD DEVELOP ALONG THE WARM FRONT AND MOVE ALONG THE COAST...THOUGH THE EXTENT TO WHICH THE LOW DEVELOPS IS UNCERTAIN. EXPECT A WINTRY MIX TO TRANSITION TO MOSTLY RAIN ACROSS MUCH OF THE DOWNEAST AREA SUNDAY AFTERNOON...WITH SNOW TRANSITIONING TO A WINTRY MIX ACROSS NORTHERN AREAS. PRECIPITATION TYPES WILL BE DEPENDENT ON HOW QUICKLY THE LOW LEVEL COLD AIR CAN BE ERODED. A STRONGER SECONDARY LOW MOVING ALONG THE COAST WOULD HELP THE LOW LEVEL COLD AIR REMAIN MORE PERSISTENT ACROSS INTERIOR DOWNEAST AREAS...WHILE A WEAKER LOW WOULD ALLOW THE LOW LEVEL COLD AIR TO BE ERODED MORE RAPIDLY. GENERALLY EXPECT STORM TOTAL SNOW ACCUMULATION OF 4 TO 7 INCHES ACROSS NORTHERN AREAS THROUGH SUNDAY WITH 3 TO 5 INCHES DOWNEAST. SLEET AND ICE ACCUMULATIONS WILL BE DEPENDENT ON THE TIMING OF THE TRANSITION FROM SNOW WHICH IS STILL UNCERTAIN AT THIS TIME. TEMPERATURES WILL BE AT BELOW NORMAL LEVELS SATURDAY...THEN AT ABOVE NORMAL LEVELS SUNDAY DEPENDENT ON THE EXTENT OF LOW LEVEL WARMING. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... LATEST RUN OF GFS/ECMWF IN GOOD AGREEMENT TRACKING LOW PRESSURE NORTH OF CWA THROUGH MONDAY WITH STRONG NORTHWEST TO NORTH GRADIENT ESTABLISHING FOR GUSTY WINDS AND A RAPID DECREASE IN TEMPERATURES. SNOW SHOWER ACTIVITY...OR MIXED PRECIPITATION ALONG DOWNEAST...WILL DIMINISH QUICKLY ACROSS THE AREA BY MONDAY NIGHT. ANOTHER LOW APPROACHES FROM THE GREAT LAKES ON TUESDAY BUT CURRENT GUIDANCE KEEPS THE SYSTEM OFFSHORE RESULTING IN CHANCE POPS ALONG DOWNEAST COAST AND SLIGHT CHANCE TO CENTRAL AREAS THROUGH EARLY THURSDAY. HIGH PRESSURE THEN BUILDS IN FROM THE WEST ON THURSDAY FOR A BRIEF RESPITE BEFORE A CLIPPER SYSTEM APPROACHES AGAIN FROM THE WEST. TEMPERATURES THROUGH THE WEEK WILL REMAIN WELL BELOW NORMALS. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... NEAR TERM: VFR CONDITIONS WILL PREVAIL AT THE SOUTHERN TERMINALS THROUGH THE PERIOD. HOWEVER, AT KCAR/KFVE/KPQI, A COLD FRONTAL PASSAGE WILL BRING SNOW SHOWERS AND PERHAPS EVEN SNOW SQUALLS. PREVAILING MVFR CONDITIONS ARE EXPECTED 22Z THU THRU 12Z FRIDAY, WITH IFR/LIFR POSSIBLE IN ANY SNOW. CONDITIONS WILL IMPROVE THROUGH THE DAY FRIDAY WITH LIFTING CEILINGS AND DECREASING COVERAGE OF SNOW SHOWERS. SHORT TERM: COULD HAVE LOCALIZED MVFR CONDITIONS ACROSS THE NORTH AND MOUNTAINS EARLY FRIDAY NIGHT. OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE REGION FRIDAY NIGHT INTO EARLY SATURDAY NIGHT. CONDITIONS WILL LOWER TO IFR/LIFR LEVELS LATER SATURDAY NIGHT WITH SIMILAR CONDITIONS PERSISTING INTO EARLY SUNDAY NIGHT. CONDITIONS WILL IMPROVE TO MVFR/VFR LEVELS ACROSS NORTHERN AREAS LATER SUNDAY NIGHT...WITH VFR CONDITIONS DEVELOPING DOWNEAST. OCCASIONAL MVFR CONDITIONS COULD PERSIST ACROSS THE NORTH AND MOUNTAINS MONDAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE REGION MONDAY INTO TUESDAY. && .MARINE... NEAR TERM: A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR TONIGHT, BUT IT HAS BEEN EXTENDED THROUGH FRIDAY. WINDS WILL INCREASE AHEAD OF AN APPROACHING COLD FRONT TONIGHT, AND THEN SWITCH TO THE WEST/NORTHWEST FRIDAY AS THE FRONT CROSSES THE GULF OF MAINE. WINDS OF 15 TO 20 KT WITH GUSTS TO 30 KT ARE EXPECTED THROUGH THE PERIOD. SHORT TERM: SMALL CRAFT ADVISORY CONDITIONS WILL OCCUR FRIDAY NIGHT INTO EARLY SATURDAY. CONDITIONS WILL BRIEFLY FALL BELOW SMALL CRAFT ADVISORY LEVELS SATURDAY AFTERNOON INTO EARLY SATURDAY NIGHT. SMALL CRAFT ADVISORY CONDITIONS WILL DEVELOP AGAIN LATER SATURDAY NIGHT. STRONG SMALL CRAFT ADVISORY...OR POSSIBLY GALE CONDITIONS...WILL OCCUR SUNDAY. VISIBILITIES WILL LOWER IN DEVELOPING SNOW AND MIXED PRECIPITATION LATER SATURDAY NIGHT...WITH MIXED PRECIPITATION CHANGING TO RAIN SUNDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST SATURDAY FOR ANZ050>052. && $$ NEAR TERM...VJN SHORT TERM...NORCROSS LONG TERM...PJR AVIATION...VJN/NORCROSS MARINE...VJN/NORCROSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
410 PM EST THU JAN 1 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 351 PM EST THU JAN 1 2015 DEEP TROUGH ALOFT CENTERED OVER HUDSON BAY. MULTIPLE SHORTWAVES MOVING THROUGH THE BASE OF THE TROUGH...BUT AFTER THE SHORTWAVE MOVED THROUGH THIS MORNING...THERE IS NO LARGER SCALE SUPPORT OVER THE AREA OR UPSTREAM. PRIMARY COLD FRONT TIED TO THE LAST SHORTWAVE IS CURRENTLY SINKING SOUTHWARD OVER UPR MICHIGAN. BAND OF HEAVY SNOW ALONG THE FRONT HAS WORKED THROUGH MARQUETTE AND MUNISING AND IS NOW ALLIGNED FM SAWYER TO CHATHAM TO SHINGLETON AND TO NEWBERRY AS OF 20Z. VSBY DOWN TO 1/4SM IN THIS SNOW BAND...BUT IT IS NOT LASTING TOO LONG. LES OVER THE WESTERN CWA IS SCUFFLING ALONG. IN FACT AFTER THE FRONT MOVED THROUGH THE KEWEENAW...SPOTS HAVE CLEARED OUT BRIEFLY. HINTS OF WIND PARALLEL BANDS OVER WESTERN LK SUPERIOR...BUT DRY AIR AND INVERSIONS BLO 5KFT IS LIMITING THIS DEVELOPMENT. BETTER LES DEVELOPMENT OVER EASTERN LK SUPERIOR WITH CLOUD STREETS EXTENDING BACK TO NCNTRL LK SUPERIOR. WILL TAKE A FEW HOURS...BUT DO EXPECT AT LEAST MODERATE LES TO DEVELOP IN THE NW LOW-LEVEL WINDS INTO EASTERN CWA. BLYR WINDS OVER 30 KTS INTO THE EVENING WILL RESULT IN BLSN/POOR VSBY IN THE HEAVIER SNOW BANDS. INVERSIONS 5-8 KFT AND TEMPS AT INVERSION TOP OF -20C SHOULD AT LEAST RESULT IN SCT HEAVIER SNOW SHOWERS. 17Z HRRR DOING NICE JOB WITH EXPECTED EVOLUTION THROUGH THE EVENING...THOUGH IT SEEMS A BIT SLOW WITH TIMING OF HEAVIER SNOW BAND TIED TO THE FRONT. ADDITIONAL SNOW AMOUNTS SHOULD STAY IN CHECK GIVEN LACK OF ENHANCED MOISTURE AND LIFT SINCE WE ARE WITHIN A PURE LES REGIME. SUPPOSE IF SNOW BANDS CAN STAY ANCHORED IN ONE PLACE THROUGH THE NIGHT...MAY SEE SEVERAL INCHES OF FLUFFY ACCUMS AS ALL CONVECTIVE DEPTH IS WITHIN THE DGZ. ALREADY ISSUED LES ADVISORY THROUGH MIDNIGHT FOR ALGER...NORTHERN SCHOOLCRAFT...AND LUCE COUNTIES. AFTER MIDNIGHT SEEMS THAT DRY AIR AND LOWER INVERSIONS THAT ARE AFFECTING WESTERN LK SUPERIOR AND CWA WILL PUT CRIMP IN THE LES INTENSITY OVERNIGHT. WEAK LES WILL CONTINUE INTO FRIDAY...MAINLY FOR AREAS FAVORED BY WNW-W WINDS...SO ESSENTIALLY THE SNOW BELTS OF THE KEWEENAW AND ALSO TO THE EAST OF MUNISING. CONDITIONS EVEN MORE UNFAVORABLE THAN LATER TONIGHT...BUT WITH DGZ DOMINATING THE CONVECTIVE LAYER STILL COULD SQUEEZE OUT A COUPLE MORE INCHES OF FLUFF IN PERSISTENT SNOW SHOWERS. AWAY FM THE LES TONIGHT...LOWERED SKY COVER AND TEMPERATURES AS THE DRIER AIR SHOULD WIN OUT AS IS OCCURRING UPSTREAM IN MINNESOTA AND NORTHWEST ONTARIO THIS AFTN. INTERIOR TEMPS SHOULD DIP WELL BLO ZERO ONCE THE NW WINDS BEHIND THE COLD FRONT BEGIN TO BACK OFF. SHOULD BE SHARP GRADIENT TO MIN TEMPS AS YOU GET CLOSER TO LK SUPERIOR DUE TO LINGERING LAKE EFFECT CLOUDS AS 925MB WINDS STAY WNW-NW THROUGH THE NIGHT. ALSO MAY SEE TEMPS STEADY OR RISE LATE IN THE WEST WITH ADVANCING DECK OF 6-9KFT ALTOSTRATUS CLOUDS. ANOTHER COOL DAY WITH AFTN READINGS IN THE TEENS OVER THE CWA. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 408 PM EST THU JAN 1 2015 A PROMINENT RIDGE GRADUALLLY BUILDING TO THE EAST INTO WRN NOAM WILL MAINTAIN A BROAD TROUGH FROM CENTRAL CANADA INTO THE GREAT LAKES. AFTER LOW PRESSURE SYSTEM LIFTS NE FROM THE CNTRL GREAT LAKES...MUCH COLDER AIR WILL MOVE INTO THE REGION AND REMAIN THROUGH MUCH OF NEXT WEEK KEEPING LES GOING FOR MAINLY NW TO WNW FLOW FAVORED LOCATIONS. FRI NIGHT AND SAT...A BROAD 850-600 MB WARM ADVECTION 280K-295 ISENTROPIC LIFT ZONE WILL DEVELOP FROM THE NRN PLAINS INTO NRN MN AND NRN LAKE SUPERIOR IN RESPONSE TO THE DEVELOPING TROUGH OVER THE PLAINS AND UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A 250-300 MB JET STREAK THROUGH NRN ONTARIO. THE MODELS KEEP MOST OF THE PCPN WITH THIS FEATURE NORTH OF UPPER MI. WAA WILL RAISE TEMPS AT OR SLIGHTLY ABOVE AVERAGE WITH READINGS IN THE MID TO UPPER 20S. SAT NIGHT INTO SUN...A SHRTWV ORIGINATING FROM THE GULF OF ALASKA DIVING INTO THE WRN CONUS TROUGH WILL HELP EJECT THE SW CLOSED LOW NE TOWARD THE GREAT LAKES. THE 12Z GFS/ECMWF ALONG WITH ENSEMBLES FAVOR A LOW TRACK FROM THE SRN END OF LAKE MI TO CNTRL LAKE HURON AND THEN NE INTO QUEBEC. STRONG 700-300 MB QVECTOR CONV ASSOCIATED WITH THE SHRTWV WILL SUPPORT A BROAD AREA OF SNOW FROM WI INTO UPPER MI BY LATE SAT AND ESPECIALLY LATE SAT NIGHT. MDLS CONSENSUS QPF IN THE 0.20 TO 0.35 INCH RANGE WITH SLR VALUES AROUND 14/1 WILL SUPPORT POTENTIAL FOR 3 TO 6 INCHES BY 18Z/SUN. ADDITIONAL SUPPORT FOR HEAVIER SNOW IS EXPECTED OVER THE NORTH CYCLONIC NRLY FLOW AND 850 MB TEMPS DROPPING FROM -10C TO -15C BY 12Z TO -14C TO -19C BY 18Z WILL RESULT HIGHER AMOUNTS THROUGH LAKE ENHANCEMENT. BY SUN AFTERNOON THE DEEPER MOISTURE AND SYNOPTIC SUPPORT LIFT QUICKLY WITH A TRANSITION TO LIGHTER PURE LES. SUN NIGHT INTO MON...VERY COLD ARCTIC AIR WILL PLUNGE INTO THE REGION WITH 850 MB TEMPS DROPPING TO AROUND -27C BY 12Z MON. THIS WILL LOWER THE DGZ TOWARD THE SFC AND REDUCE POTENTIAL FOR SIGNIFICANT LES. HOWEVER...WIND CHILL WITH A MORE WRLY SFC WIND COMPONENT RESULTING FROM LAKE INDUCED TROUGHING WILL ALLOW TEMPS TO DROP OFF OVER MUCH OF THE CWA. WIND CHILL VALUES IN THE -20 TO -35 RANGE ARE EXPECTED. TUE-THU...A FEW CLIPPER SHRTWVS ARE LIKELY TO MOVE THROUGH THE REGION WITH NW-NNW MID LEVEL FLOW IN PLACE. THIS MAY BRING REINFORCING BOUTS OF COLD AIR AND SHIFT THE POSITIONS OF THE HEAVIER LES BANDS. TEMPS MAY MODERATE SLIGHTLY IF SFC WINDS VEER MORE TO THE NW WITH MORE MARINE MODIFICATION. HOWEVER...WIND CHILLS MAY REMAIN NEAR ADVY THRESHOLD DURING THE LATER NIGHT INTO MORNING HOURS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1243 PM EST THU JAN 1 2015 COLD FRONT HAS MADE IT THROUGH KCMX AND WILL IMPACT KIWD AND KSAW WITH A PERIOD OF SNOW SHOWERS AND BLOWING SNOW THIS AFTN. AT KIWD AND KSAW...GENERALLY THE CIGS WILL BE MVFR INTO TONIGHT. VSBY WILL BE IFR OR MVFR...BUT WILL BEGIN TO IMPROVE BY EARLY EVENING AS DRIER AIR ERODES THE LAKE EFFECT SNOW SHOWERS. WILL SEE IMPROVEMENT TO VFR LATE TONIGHT INTO FRIDAY AT KIWD AND KSAW. AT KCMX...PERSISTENT WNW- NW FLOW OFF LK SUPERIOR WILL KEEP LAKE EFFECT SNOW SHOWERS WITH IFR TO MVFR VSBY THROUGH THE PERIOD. STRONGEST WINDS WITH BLSN THIS AFTN...THEN WINDS DIMINISH SIGNIFICANTLY THIS EVENING AND OVERNIGHT TONIGHT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 351 PM EST THU JAN 1 2015 NW GALES DIMINISH THIS EVENING OVER THE EAST HALF. HEAVY FREEZING SPRAY WILL ALSO END LATE TONIGHT. WINDS SETTLE DOWN TO LESS THAN 25 KTS LATER TONIGHT THROUGH FRIDAY NIGHT AS HIGH PRESSURE MOVES OVERHEAD. EXPECT A BRIEF PERIOD OF STRONGER SE WINDS ON SATURDAY...BUT THE BETTER CHANCE OF STRONGER WINDS WILL BE LATE SATURDAY NIGHT INTO SUNDAY AS NORTH TO NORTHWEST WINDS INCREASE AS A LOW PRESSURE SYSTEM LIFTS OVER THE GREAT LAKES THEN MOVES EAST OVER QUEBEC. BEST SHOT OF GALES WILL BE OVER THE EAST HALF OF LK SUPERIOR ON SUNDAY. NW WINDS TO 30 KTS WILL LINGER OVER MUCH OF LK SUPERIOR INTO EARLY NEXT WEEK BEHIND THE WEEKEND SYSTEM. MORE HEAVY FREEZING SPRAY IS EXPECTED LATE THIS WEEKEND INTO EARLY NEXT WEEK AS ARCTIC AIR FLOWS ACROSS LK SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ006- 007-085. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST FRIDAY FOR LSZ265- 267. GALE WARNING UNTIL 6 PM EST THIS EVENING FOR LSZ266-267. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ FRIDAY FOR LSZ241>245-263-264-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLA LONG TERM...JLB AVIATION...JLA MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
353 PM EST THU JAN 1 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 351 PM EST THU JAN 1 2015 DEEP TROUGH ALOFT CENTERED OVER HUDSON BAY. MULTIPLE SHORTWAVES MOVING THROUGH THE BASE OF THE TROUGH...BUT AFTER THE SHORTWAVE MOVED THROUGH THIS MORNING...THERE IS NO LARGER SCALE SUPPORT OVER THE AREA OR UPSTREAM. PRIMARY COLD FRONT TIED TO THE LAST SHORTWAVE IS CURRENTLY SINKING SOUTHWARD OVER UPR MICHIGAN. BAND OF HEAVY SNOW ALONG THE FRONT HAS WORKED THROUGH MARQUETTE AND MUNISING AND IS NOW ALLIGNED FM SAWYER TO CHATHAM TO SHINGLETON AND TO NEWBERRY AS OF 20Z. VSBY DOWN TO 1/4SM IN THIS SNOW BAND...BUT IT IS NOT LASTING TOO LONG. LES OVER THE WESTERN CWA IS SCUFFLING ALONG. IN FACT AFTER THE FRONT MOVED THROUGH THE KEWEENAW...SPOTS HAVE CLEARED OUT BRIEFLY. HINTS OF WIND PARALLEL BANDS OVER WESTERN LK SUPERIOR...BUT DRY AIR AND INVERSIONS BLO 5KFT IS LIMITING THIS DEVELOPMENT. BETTER LES DEVELOPMENT OVER EASTERN LK SUPERIOR WITH CLOUD STREETS EXTENDING BACK TO NCNTRL LK SUPERIOR. WILL TAKE A FEW HOURS...BUT DO EXPECT AT LEAST MODERATE LES TO DEVELOP IN THE NW LOW-LEVEL WINDS INTO EASTERN CWA. BLYR WINDS OVER 30 KTS INTO THE EVENING WILL RESULT IN BLSN/POOR VSBY IN THE HEAVIER SNOW BANDS. INVERSIONS 5-8 KFT AND TEMPS AT INVERSION TOP OF -20C SHOULD AT LEAST RESULT IN SCT HEAVIER SNOW SHOWERS. 17Z HRRR DOING NICE JOB WITH EXPECTED EVOLUTION THROUGH THE EVENING...THOUGH IT SEEMS A BIT SLOW WITH TIMING OF HEAVIER SNOW BAND TIED TO THE FRONT. ADDITIONAL SNOW AMOUNTS SHOULD STAY IN CHECK GIVEN LACK OF ENHANCED MOISTURE AND LIFT SINCE WE ARE WITHIN A PURE LES REGIME. SUPPOSE IF SNOW BANDS CAN STAY ANCHORED IN ONE PLACE THROUGH THE NIGHT...MAY SEE SEVERAL INCHES OF FLUFFY ACCUMS AS ALL CONVECTIVE DEPTH IS WITHIN THE DGZ. ALREADY ISSUED LES ADVISORY THROUGH MIDNIGHT FOR ALGER...NORTHERN SCHOOLCRAFT...AND LUCE COUNTIES. AFTER MIDNIGHT SEEMS THAT DRY AIR AND LOWER INVERSIONS THAT ARE AFFECTING WESTERN LK SUPERIOR AND CWA WILL PUT CRIMP IN THE LES INTENSITY OVERNIGHT. WEAK LES WILL CONTINUE INTO FRIDAY...MAINLY FOR AREAS FAVORED BY WNW-W WINDS...SO ESSENTIALLY THE SNOW BELTS OF THE KEWEENAW AND ALSO TO THE EAST OF MUNISING. CONDITIONS EVEN MORE UNFAVORABLE THAN LATER TONIGHT...BUT WITH DGZ DOMINATING THE CONVECTIVE LAYER STILL COULD SQUEEZE OUT A COUPLE MORE INCHES OF FLUFF IN PERSISTENT SNOW SHOWERS. AWAY FM THE LES TONIGHT...LOWERED SKY COVER AND TEMPERATURES AS THE DRIER AIR SHOULD WIN OUT AS IS OCCURRING UPSTREAM IN MINNESOTA AND NORTHWEST ONTARIO THIS AFTN. INTERIOR TEMPS SHOULD DIP WELL BLO ZERO ONCE THE NW WINDS BEHIND THE COLD FRONT BEGIN TO BACK OFF. SHOULD BE SHARP GRADIENT TO MIN TEMPS AS YOU GET CLOSER TO LK SUPERIOR DUE TO LINGERING LAKE EFFECT CLOUDS AS 925MB WINDS STAY WNW-NW THROUGH THE NIGHT. ALSO MAY SEE TEMPS STEADY OR RISE LATE IN THE WEST WITH ADVANCING DECK OF 6-9KFT ALTOSTRATUS CLOUDS. ANOTHER COOL DAY WITH AFTN READINGS IN THE TEENS OVER THE CWA. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 501 AM EST THU JAN 1 2015 PERSISTENT RIDGING OVER THE EASTERN PACIFIC/NAMERICA WEST COAST REGION WILL MAINTAIN A BROAD UPPER TROUGH OVER MUCH OF CANADA AND THE GREAT LAKES REGION THROUGH THE FIRST WEEK OF JANUARY RESULTING IN BELOW NORMAL TEMPERATURES AND PERIODS OF LAKE EFFECT SNOW FOR UPPER MI. BEGINNING FRIDAY...MODEL CONSENSUS SUGGESTS WINDS WL BACK MORE WESTERLY AGAIN AS SFC RDG AXIS ADVANCES ACROSS AREA FROM THE NRN PLAINS. THE GENERALLY WEAK WRLY FLOW ALONG WITH ENHANCED LOW-LVL CONVERGENCE FROM LAND BREEZES WL HELP FOCUS GENERALLY LIGHT LAKE EFFECT SNOW ACROSS THE KEWEENAN PENINSULA AND THE FAR ERN SHORELINE OF THE CWA AS INVERSION BASES CRASH BLO 5KFT WITH DRY AIR NOTED BENEATH THE INVERSION. SINCE MUCH OF THE DGZ IN STILL WITHIN THE CLOUD LAYER...LES BANDS COULD YIELD 1-2 INCHES OF FLUFFY ACCUMULATION DURING THE DAY. WAA CLOUDS AHEAD OF SHORTWAVE MOVING IN FROM THE NRN PLAINS WILL LIMIT RADIATIONAL COOLING FRIDAY NIGHT BUT TEMPS SHOULD STILL APPROACH ZERO OR MAYBE EVEN DIP BLO ZERO AT A FEW OF THE TYPICAL COLDER LOCATIONS OVER THE WESTERN INTERIOR. THIS WEEKEND...FOCUS IS ON PHASING/INTERACTION OF SPLIT FLOW. TWO FEATURES WILL COME INTO PLAY...ONE WILL BE THE REMNANTS OF A CLOSED LOW NOW PRODUCING SNOW OVER THE SW CONUS...AND THE SECOND IS A NRN BRANCH SHORTWAVE NOW OVER THE ALEUTIAN ISLANDS WHICH IS FCST TO DIVE SE ACROSS THE NRN ROCKIES FRI NIGHT AND THEN THROUGH THE PLAINS STATES ON SAT. ASSOCIATED STRONG MID LEVEL WARM AIR ADVECTION AHEAD OF THIS SHORTWAVE AND ITS ASSOC SFC LOW WILL SPREAD SNOW EAST INTO MAINLY THE NORTHWEST HALF OF THE CWA ON SAT. WHILE THE MODELS STILL PEG THE HEAVIEST SNOW TO OCCUR OVER LAKE SUPERIOR...WILL CONTINUE TO SHOW SOME LIKELY POPS OVER AND AROUND THE KEWEENAW PENINSULA FOR SATURDAY. AS THIS SNOW IS OCCURRING...THE NORTHERN SHORTWAVE WILL CONTINUE TO DIVE SOUTHEAST AND BEGIN TO PHASE WITH THE REMNANTS OF THE SW CONUS UPPER LOW WHICH WILL LEAD TO BOTH FEATURES EJECTING NORTHEAST THROUGH THE LOWER GREAT LAKES REGION SATURDAY NIGHT INTO SUNDAY. THE 00Z ECMWF...GFS AND NAM ALL TRENDING DEEPER AND FARTHER WEST WITH RESULTING SFC LOW WHICH BLEND OF THESE MODELS SHOW A TRACK THROUGH SRN LWR MI TO NEAR GEORGIAN BAY BY 12Z SUNDAY. THE GEM-NH MEANWHILE AFTER SHOWING A SIMILAR TRACK TO THE 00Z ECMWF/GFS BLEND HAS NOW TRENDED FARTHER EAST THROUGH SE LOWER MI INTO ERN ONTARIO. IF THE LATEST GFS/ECMWF SOLNS HOLD TRUE THIS WOULD MEAN A GREATER POTENTIAL FOR SYNOPTIC PCPN TO SPREAD INTO UPPER MI...ESPECIALLY THE EAST HALF...ALONG WITH A GREATER POTENTIAL FOR NORTH FLOW LAKE ENHANCED SNOW ON THE BACKSIDE OF THE SYSTEM. WILL LIKELY NEED TO TREND POPS UPWARD ACROSS THE CWA AND ESPECIALLY ALONG LAKE SUPERIOR ZONES WITH A GREATER POTENTIAL FOR LAKE ENHANCED SNOW SAT NIGHT INTO SUNDAY. WINDS WILL ALSO RAMP UP WITH TIGHTER GRADIENT ON BACKSIDE OF SYSTEM WHICH WILL ALSO RESULT IN MORE BLOWING SNOW. WILL HIGHLIGHT POTENTIAL FOR MODERATE SNOW AND BLOWING SNOW IN HWO...ESPECIALLY ALONG LAKE SUPERIOR AND THE EAST HALF OF THE CWA FOR SAT NIGHT INTO SUNDAY EVENING. LATE SUNDAY NIGHT INTO MONDAY NIGHT...WEAKENING PRES GRADIENT WILL ALLOW WINDS TO DIMINISH ESPECIALLY OVER THE INTERIOR. WINDS WILL ALSO BE BACKING MORE WESTERLY ESPECIALLY BY MONDAY IN ADVANCE OF STRONG SFC HIGH PRES RDG BUILDING IN FROM THE NRN PLAINS...SO EXPECT LES TO EVENTUALLY BECOME MORE CONFINED TO KEWEENAW AND FAR ERN SHORELINE AREAS OF THE CWA MONDAY AFTERNOON INTO MON NIGHT. WITH HEART OF COLDEST AIR (850 MB TEMPS OF -26 TO -28C) COMING ACROSS THE UPPER LAKES...EXPECT VERY COLD TEMPS SUN NIGHT AND MONDAY. EXPECT MUCH OF THE INTERIOR CWA TO FALL BLO ZERO AND WOULD NOT BE SURPRISED TO SEE SOME WESTERN INTERIOR LOCATIONS FALL WELL INTO THE TEENS BLO ZERO... ESPECIALLY ALONG THE WI BORDER. HIGHS MONDAY WILL REMAIN VERY COLD WITH READINGS RANGING FROM THE SINGLE DIGITS BLO ZERO WESTERN INTERIOR TO THE SINGLE DIGITS ABV ZERO EAST AND ALONG THE GREAT LAKES. TUESDAY INTO WEDNESDAY...MODELS IN REASONABLY GOOD AGREEMENT SHOWING ANOTHER CLIPPER SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES ON TUESDAY WITH ANOTHER REINFORCING SHOT OF ARCTIC AIR (8H TEMPS FALL AGAIN TO -28C TO -30C) AS WINDS VEER TO THE NW. THIS WILL BRING LES FARTHER INLAND AGAIN AFFECTING THE NRN TIER AND ERN HALF COUNTIES FROM LATE TUE THROUGH WED. LOOK LIKE ONLY THE FAR SOUTH CENTRAL WOULD ESCAPE THE LES. WITH SUCH A COLD ARCTIC AIRMASS FCST THE DGZ WILL GET SQUASHED NEAR THE LAKE SFC WHICH WILL LIKELY RESULT IN SMALLER FLAKE SIZE. THIS WILL LIMIT LES ACCUMULATION BUT AT SAME TIME WILL BE MORE EFFECTIVE FOR REDUCING VSBY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1243 PM EST THU JAN 1 2015 COLD FRONT HAS MADE IT THROUGH KCMX AND WILL IMPACT KIWD AND KSAW WITH A PERIOD OF SNOW SHOWERS AND BLOWING SNOW THIS AFTN. AT KIWD AND KSAW...GENERALLY THE CIGS WILL BE MVFR INTO TONIGHT. VSBY WILL BE IFR OR MVFR...BUT WILL BEGIN TO IMPROVE BY EARLY EVENING AS DRIER AIR ERODES THE LAKE EFFECT SNOW SHOWERS. WILL SEE IMPROVEMENT TO VFR LATE TONIGHT INTO FRIDAY AT KIWD AND KSAW. AT KCMX...PERSISTENT WNW- NW FLOW OFF LK SUPERIOR WILL KEEP LAKE EFFECT SNOW SHOWERS WITH IFR TO MVFR VSBY THROUGH THE PERIOD. STRONGEST WINDS WITH BLSN THIS AFTN...THEN WINDS DIMINISH SIGNIFICANTLY THIS EVENING AND OVERNIGHT TONIGHT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 351 PM EST THU JAN 1 2015 NW GALES DIMINISH THIS EVENING OVER THE EAST HALF. HEAVY FREEZING SPRAY WILL ALSO END LATE TONIGHT. WINDS SETTLE DOWN TO LESS THAN 25 KTS LATER TONIGHT THROUGH FRIDAY NIGHT AS HIGH PRESSURE MOVES OVERHEAD. EXPECT A BRIEF PERIOD OF STRONGER SE WINDS ON SATURDAY...BUT THE BETTER CHANCE OF STRONGER WINDS WILL BE LATE SATURDAY NIGHT INTO SUNDAY AS NORTH TO NORTHWEST WINDS INCREASE AS A LOW PRESSURE SYSTEM LIFTS OVER THE GREAT LAKES THEN MOVES EAST OVER QUEBEC. BEST SHOT OF GALES WILL BE OVER THE EAST HALF OF LK SUPERIOR ON SUNDAY. NW WINDS TO 30 KTS WILL LINGER OVER MUCH OF LK SUPERIOR INTO EARLY NEXT WEEK BEHIND THE WEEKEND SYSTEM. MORE HEAVY FREEZING SPRAY IS EXPECTED LATE THIS WEEKEND INTO EARLY NEXT WEEK AS ARCTIC AIR FLOWS ACROSS LK SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ006- 007-085. LAKE SUPERIOR... HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST FRIDAY FOR LSZ265- 267. GALE WARNING UNTIL 6 PM EST THIS EVENING FOR LSZ266-267. HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ FRIDAY FOR LSZ241>245-263-264-266. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLA LONG TERM...VOSS AVIATION...JLA MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1246 PM EST THU JAN 1 2015 .UPDATE... ISSUED AT 1107 AM EST THU JAN 1 2015 WIDESPREAD NOAA WEATHER RADIO OUTAGE ACROSS UPR MICHIGAN CONTINUES AT THIS HOUR DUE TO LARGER SCALE COMMS OUTAGE WITH VERIZON. SHORTWAVE WITH WIDEPSREAD LGT SNOW IS EXITING EASTERN CWA. SFC COLD FRONT IS FINALLY STARTING TO SINK ACROSS SOUTHERN HALF OF LK SUPERIOR THOUGH IT IS TAKING ITS TIME IN DOING SO. LES OVER THE KEWEENAW THIS MORNING HAS BEEN HEAVY WITH 1+ INCH PER HOUR RATES. EXPECT LES TO BECOME LESS FOCUSED THOUGH THROUGH MIDDAY AS WINDS SHIFT FROM THE STRONG CONVERGENT WESTERLY FLOW TO A MORE SHEARED NORTHWEST FLOW BEHIND THE COLD FRONT. LAKE EFFECT SNOW ADVISORY SET TO EXPIRE AT 18Z TODAY FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES. BASED ON EXPECTED TRENDS IN LES AND WIND THAT LOOKS GOOD AND WILL NOT MAKE ANY EXTENSIONS ATTM. ATTN THEN TURNS TO FROPA OVER EASTERN CWA EARLY TO MID AFTN. EXPECT DECENT CONVERGENCE BAND TO FIRST AFFECT SNOW BELTS EAST OF MARQUETTE THEN NW FLOW LES WILL DEVELOP. RAP SOUNDINGS INDICATE INVERSIONS TO 7-8KFT WITH TEMPS AROUND -20C AT INVERSION TOP THROUGH EARLY EVENING. MIXED LAYER WINDS 25-35 KTS WILL RESULT IN WINDY CONDITIONS AFTER FROPA WITH BLSN/POOR VSBY. WOULD EXPECT SNOWFALL RATES BTWN 0.5-1.0 INCH PER HOUR THIS AFTN INTO THE EARLY EVENING. MUCH OF THE CONVECTIVE LAYER IS WITHIN THE DGZ...SO SLR/S WILL BE WELL OVER 20:1. OPTED TO ISSUE A LAKE EFFECT SNOW ADVISORY FOR ALGER...NORTHERN SCHOOLCRAFT...AND LUCE COUNTIES THROUGH THE EVENING. SNOW AND BLSN WILL MAKE TRAVEL DIFFICULT INTO THE EARLY EVENING WITH VSBY DOWN TO 1/4SM AT TIMES...AND SNOW AMOUNTS WILL BE BOOSTED BY HIGHER SLR/S AND DECENTLY HIGH INVERSIONS. IN WAKE OF FROPA LATE THIS EVENING AND OVERNIGHT TONIGHT...EXPECT DIMINISHING LES AS INVERSIONS FALL BLO 5KFT...BUT DIMINISHING WINDS AND MOST OF THE CONVECTIVE LAYER WITHIN THE DGZ WILL STILL BOOST SNOW AMOUNTS. EXPECT SNOW TOTALS TODAY INTO THIS EVENING OF 2 TO 4 INCHES AND ANOTHER 1 TO 3 INCHES LATER THIS EVENING INTO THE OVERNIGHT. UPDATED WSW STATEMENT ALREADY OUT. COORD WITH APX ON THE LAKE EFFECT SNOW ADVISORY FOR LUCE COUNTY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 546 AM EST THU JAN 1 2015 THE STACKED SFC-500MB LOW OVER S HUDSON BAY WILL WEAKEN SLIGHTLY AND DRIFT OVER N QUEBEC OVERNIGHT TONIGHT. THIS WILL KEEP THE UPPER GREAT LAKES IN NW FLOW ALOFT WITH SEVERAL SMALL WAVES SHIFTING ACROSS THE AREA. A DOMINANT SFC TROUGH/COLD FRONT HOVERING NEAR THE N MN BORDER WILL SINK ACROSS UPPER MI THROUGH THE DAY TODAY. THIS...AND AN SHORTWAVE PUSHING ACROSS THE AREA WILL ALLOW FOR SOME INTENSIFICATION TO SNOW SHOWERS THIS AFTERNOON. AS A RESULT...WILL KEEP THE HIGH CHANCE POPS GOING ACROSS THE AREA AROUND 18Z...BEFORE DIMINISHING THEM AGAIN TO ALONG THE LAKE SUPERIOR SHORELINE THIS EVENING. 850MB TEMPS WILL FALL FROM THE MORNING READINGS OF -12 TO -15C TO -18 TO -21C BY DAYBREAK FRIDAY. AS FOR SPECIFICS... LES CONTINUES ACROSS THE KEWEENAW PENINSULA...WITH A DOMINANT BAND STRETCHING ACROSS LAKE SUPERIOR TO NEAR WHITEFISH POINT. LOOK FOR THE EASTERN LAKE SUPERIOR BAND TO SLOWLY SINK S ONSHORE AS THE CONVERGENT W TO SW WINDS KEEPING IT JUST OFF THE SHORE RELAX AND NW WINDS OFF THE LAKE WIN OUT LATER THIS MORNING. THIS WILL PUSH THE BAND OVER N LUCE COUNTY...WITH 1-3 INCHES OF SNOW FCST FOR MUCH OF LUCE COUNTY. ANOTHER 1-3 INCHES IS EXPECTED TONIGHT WITH BETTER CONVERGENCE NEAR WHITEFISH POINT. WILL KEEP THE LES ADVISORY FOR SNOW AND BLOWING/DRIFTING SNOW GOING ACROSS THE KEWEENAW PENINUSLA. EXPECT ANY DOMINANT BANDS...HIGHER SNOW AMOUNTS...TO DRIFT AROUND AND S OF CMX...WITH NEW SNOW TODAY OF 1-3 INCHES. EXPECT ANOTHER COLD NIGHT...WITH LOWS GENERALLY IN THE SINGLE DIGITS BELOW AND ABOVE ZERO...WARMEST WHERE CLOUDS AND SNOW SHOWERS LINGER ALONG LAKE SUPERIOR. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 501 AM EST THU JAN 1 2015 PERSISTENT RIDGING OVER THE EASTERN PACIFIC/NAMERICA WEST COAST REGION WILL MAINTAIN A BROAD UPPER TROUGH OVER MUCH OF CANADA AND THE GREAT LAKES REGION THROUGH THE FIRST WEEK OF JANUARY RESULTING IN BELOW NORMAL TEMPERATURES AND PERIODS OF LAKE EFFECT SNOW FOR UPPER MI. BEGINNING FRIDAY...MODEL CONSENSUS SUGGESTS WINDS WL BACK MORE WESTERLY AGAIN AS SFC RDG AXIS ADVANCES ACROSS AREA FROM THE NRN PLAINS. THE GENERALLY WEAK WRLY FLOW ALONG WITH ENHANCED LOW-LVL CONVERGENCE FROM LAND BREEZES WL HELP FOCUS GENERALLY LIGHT LAKE EFFECT SNOW ACROSS THE KEWEENAN PENINSULA AND THE FAR ERN SHORELINE OF THE CWA AS INVERSION BASES CRASH BLO 5KFT WITH DRY AIR NOTED BENEATH THE INVERSION. SINCE MUCH OF THE DGZ IN STILL WITHIN THE CLOUD LAYER...LES BANDS COULD YIELD 1-2 INCHES OF FLUFFY ACCUMULATION DURING THE DAY. WAA CLOUDS AHEAD OF SHORTWAVE MOVING IN FROM THE NRN PLAINS WILL LIMIT RADIATIONAL COOLING FRIDAY NIGHT BUT TEMPS SHOULD STILL APPROACH ZERO OR MAYBE EVEN DIP BLO ZERO AT A FEW OF THE TYPICAL COLDER LOCATIONS OVER THE WESTERN INTERIOR. THIS WEEKEND...FOCUS IS ON PHASING/INTERACTION OF SPLIT FLOW. TWO FEATURES WILL COME INTO PLAY...ONE WILL BE THE REMNANTS OF A CLOSED LOW NOW PRODUCING SNOW OVER THE SW CONUS...AND THE SECOND IS A NRN BRANCH SHORTWAVE NOW OVER THE ALEUTIAN ISLANDS WHICH IS FCST TO DIVE SE ACROSS THE NRN ROCKIES FRI NIGHT AND THEN THROUGH THE PLAINS STATES ON SAT. ASSOCIATED STRONG MID LEVEL WARM AIR ADVECTION AHEAD OF THIS SHORTWAVE AND ITS ASSOC SFC LOW WILL SPREAD SNOW EAST INTO MAINLY THE NORTHWEST HALF OF THE CWA ON SAT. WHILE THE MODELS STILL PEG THE HEAVIEST SNOW TO OCCUR OVER LAKE SUPERIOR...WILL CONTINUE TO SHOW SOME LIKELY POPS OVER AND AROUND THE KEWEENAW PENINSULA FOR SATURDAY. AS THIS SNOW IS OCCURRING...THE NORTHERN SHORTWAVE WILL CONTINUE TO DIVE SOUTHEAST AND BEGIN TO PHASE WITH THE REMNANTS OF THE SW CONUS UPPER LOW WHICH WILL LEAD TO BOTH FEATURES EJECTING NORTHEAST THROUGH THE LOWER GREAT LAKES REGION SATURDAY NIGHT INTO SUNDAY. THE 00Z ECMWF...GFS AND NAM ALL TRENDING DEEPER AND FARTHER WEST WITH RESULTING SFC LOW WHICH BLEND OF THESE MODELS SHOW A TRACK THROUGH SRN LWR MI TO NEAR GEORGIAN BAY BY 12Z SUNDAY. THE GEM-NH MEANWHILE AFTER SHOWING A SIMILAR TRACK TO THE 00Z ECMWF/GFS BLEND HAS NOW TRENDED FARTHER EAST THROUGH SE LOWER MI INTO ERN ONTARIO. IF THE LATEST GFS/ECMWF SOLNS HOLD TRUE THIS WOULD MEAN A GREATER POTENTIAL FOR SYNOPTIC PCPN TO SPREAD INTO UPPER MI...ESPECIALLY THE EAST HALF...ALONG WITH A GREATER POTENTIAL FOR NORTH FLOW LAKE ENHANCED SNOW ON THE BACKSIDE OF THE SYSTEM. WILL LIKELY NEED TO TREND POPS UPWARD ACROSS THE CWA AND ESPECIALLY ALONG LAKE SUPERIOR ZONES WITH A GREATER POTENTIAL FOR LAKE ENHANCED SNOW SAT NIGHT INTO SUNDAY. WINDS WILL ALSO RAMP UP WITH TIGHTER GRADIENT ON BACKSIDE OF SYSTEM WHICH WILL ALSO RESULT IN MORE BLOWING SNOW. WILL HIGHLIGHT POTENTIAL FOR MODERATE SNOW AND BLOWING SNOW IN HWO...ESPECIALLY ALONG LAKE SUPERIOR AND THE EAST HALF OF THE CWA FOR SAT NIGHT INTO SUNDAY EVENING. LATE SUNDAY NIGHT INTO MONDAY NIGHT...WEAKENING PRES GRADIENT WILL ALLOW WINDS TO DIMINISH ESPECIALLY OVER THE INTERIOR. WINDS WILL ALSO BE BACKING MORE WESTERLY ESPECIALLY BY MONDAY IN ADVANCE OF STRONG SFC HIGH PRES RDG BUILDING IN FROM THE NRN PLAINS...SO EXPECT LES TO EVENTUALLY BECOME MORE CONFINED TO KEWEENAW AND FAR ERN SHORELINE AREAS OF THE CWA MONDAY AFTERNOON INTO MON NIGHT. WITH HEART OF COLDEST AIR (850 MB TEMPS OF -26 TO -28C) COMING ACROSS THE UPPER LAKES...EXPECT VERY COLD TEMPS SUN NIGHT AND MONDAY. EXPECT MUCH OF THE INTERIOR CWA TO FALL BLO ZERO AND WOULD NOT BE SURPRISED TO SEE SOME WESTERN INTERIOR LOCATIONS FALL WELL INTO THE TEENS BLO ZERO... ESPECIALLY ALONG THE WI BORDER. HIGHS MONDAY WILL REMAIN VERY COLD WITH READINGS RANGING FROM THE SINGLE DIGITS BLO ZERO WESTERN INTERIOR TO THE SINGLE DIGITS ABV ZERO EAST AND ALONG THE GREAT LAKES. TUESDAY INTO WEDNESDAY...MODELS IN REASONABLY GOOD AGREEMENT SHOWING ANOTHER CLIPPER SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES ON TUESDAY WITH ANOTHER REINFORCING SHOT OF ARCTIC AIR (8H TEMPS FALL AGAIN TO -28C TO -30C) AS WINDS VEER TO THE NW. THIS WILL BRING LES FARTHER INLAND AGAIN AFFECTING THE NRN TIER AND ERN HALF COUNTIES FROM LATE TUE THROUGH WED. LOOK LIKE ONLY THE FAR SOUTH CENTRAL WOULD ESCAPE THE LES. WITH SUCH A COLD ARCTIC AIRMASS FCST THE DGZ WILL GET SQUASHED NEAR THE LAKE SFC WHICH WILL LIKELY RESULT IN SMALLER FLAKE SIZE. THIS WILL LIMIT LES ACCUMULATION BUT AT SAME TIME WILL BE MORE EFFECTIVE FOR REDUCING VSBY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 1243 PM EST THU JAN 1 2015 COLD FRONT HAS MADE IT THROUGH KCMX AND WILL IMPACT KIWD AND KSAW WITH A PERIOD OF SNOW SHOWERS AND BLOWING SNOW THIS AFTN. AT KIWD AND KSAW...GENERALLY THE CIGS WILL BE MVFR INTO TONIGHT. VSBY WILL BE IFR OR MVFR...BUT WILL BEGIN TO IMPROVE BY EARLY EVENING AS DRIER AIR ERODES THE LAKE EFFECT SNOW SHOWERS. WILL SEE IMPROVEMENT TO VFR LATE TONIGHT INTO FRIDAY AT KIWD AND KSAW. AT KCMX...PERSISTENT WNW- NW FLOW OFF LK SUPERIOR WILL KEEP LAKE EFFECT SNOW SHOWERS WITH IFR TO MVFR VSBY THROUGH THE PERIOD. STRONGEST WINDS WITH BLSN THIS AFTN...THEN WINDS DIMINISH SIGNIFICANTLY THIS EVENING AND OVERNIGHT TONIGHT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 412 AM EST THU JAN 1 2015 A LOW OVER S HUDSON BAY WILL SHIFT INTO N QUEBEC FRIDAY MORNING. THE TROUGH EXTENDING FROM THIS LOW ACROSS LAKE SUPERIOR WILL SLOWLY WEAKEN. AS A RESULT...EXPECT THE GALES OF 35-40KTS TO SLOWLY DIMINISH TOO. WHILE HEAVY FREEZING SPRAY HAS DIMINISHED THIS MORNING...IT WILL PICK UP AGAIN OVER N LAKE SUPERIOR THIS AFTERNOON-EVENING. HIGH PRESSURE SINKING ACROSS MINNESOTA THIS EVENING WILL STRETCH FROM THE GREAT LAKES THROUGH THE OHIO VALLEY ON FRIDAY...AND EXIT TO SOUTHERN QUEBEC AND THE NEW ENGLAND STATES FRIDAY NIGHT. EXPECT A LOW ACROSS THE DAKOTAS FRIDAY NIGHT TO CONSOLIDATE WITH AN ADDITIONAL LOW ACROSS THE MISSISSIPPI VALLEY. THE NEW LOW WILL MOVE NE AND DEEPEN ACROSS LOWER MICHIGAN AND LAKE HURON SATURDAY NIGHT...AND EXIT S QUEBEC ON SUNDAY. THIS WILL BRING A TROUGH SATURDAY NIGHT INTO SUNDAY FOR LAKE SUPERIOR. N-NW GALES OF 35 TO NEAR 40KTS WILL AGAIN BE POSSIBLE SUNDAY INTO SUNDAY EVENING. BY MONDAY...A RIDGE WILL SETTLE ACROSS THE N PLAINS AND UPPER MISSISSIPPI VALLEY. HEAVY FREEZING SPRAY WILL ALSO RETURN AS A COLD RIDGE WILL SETTLE ACROSS THE N PLAINS AND UPPER MISSISSIPPI VALLEY MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ006- 007-085. LAKE SUPERIOR... GALE WARNING UNTIL 6 PM EST THIS EVENING FOR LSZ266-267. HEAVY FREEZING SPRAY WARNING UNTIL 3 AM EST FRIDAY FOR LSZ263- 264. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...KF LONG TERM...VOSS AVIATION...JLA MARINE...KF
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1107 AM EST THU JAN 1 2015 .UPDATE... ISSUED AT 1107 AM EST THU JAN 1 2015 WIDESPREAD NOAA WEATHER RADIO OUTAGE ACROSS UPR MICHIGAN CONTINUES AT THIS HOUR DUE TO LARGER SCALE COMMS OUTAGE WITH VERIZON. SHORTWAVE WITH WIDEPSREAD LGT SNOW IS EXITING EASTERN CWA. SFC COLD FRONT IS FINALLY STARTING TO SINK ACROSS SOUTHERN HALF OF LK SUPERIOR THOUGH IT IS TAKING ITS TIME IN DOING SO. LES OVER THE KEWEENAW THIS MORNING HAS BEEN HEAVY WITH 1+ INCH PER HOUR RATES. EXPECT LES TO BECOME LESS FOCUSED THOUGH THROUGH MIDDAY AS WINDS SHIFT FROM THE STRONG CONVERGENT WESTERLY FLOW TO A MORE SHEARED NORTHWEST FLOW BEHIND THE COLD FRONT. LAKE EFFECT SNOW ADVISORY SET TO EXPIRE AT 18Z TODAY FOR NORTHERN HOUGHTON AND KEWEENAW COUNTIES. BASED ON EXPECTED TRENDS IN LES AND WIND THAT LOOKS GOOD AND WILL NOT MAKE ANY EXTENSIONS ATTM. ATTN THEN TURNS TO FROPA OVER EASTERN CWA EARLY TO MID AFTN. EXPECT DECENT CONVERGENCE BAND TO FIRST AFFECT SNOW BELTS EAST OF MARQUETTE THEN NW FLOW LES WILL DEVELOP. RAP SOUNDINGS INDICATE INVERSIONS TO 7-8KFT WITH TEMPS AROUND -20C AT INVERSION TOP THROUGH EARLY EVENING. MIXED LAYER WINDS 25-35 KTS WILL RESULT IN WINDY CONDITIONS AFTER FROPA WITH BLSN/POOR VSBY. WOULD EXPECT SNOWFALL RATES BTWN 0.5-1.0 INCH PER HOUR THIS AFTN INTO THE EARLY EVENING. MUCH OF THE CONVECTIVE LAYER IS WITHIN THE DGZ...SO SLR/S WILL BE WELL OVER 20:1. OPTED TO ISSUE A LAKE EFFECT SNOW ADVISORY FOR ALGER...NORTHERN SCHOOLCRAFT...AND LUCE COUNTIES THROUGH THE EVENING. SNOW AND BLSN WILL MAKE TRAVEL DIFFICULT INTO THE EARLY EVENING WITH VSBY DOWN TO 1/4SM AT TIMES...AND SNOW AMOUNTS WILL BE BOOSTED BY HIGHER SLR/S AND DECENTLY HIGH INVERSIONS. IN WAKE OF FROPA LATE THIS EVENING AND OVERNIGHT TONIGHT...EXPECT DIMINISHING LES AS INVERSIONS FALL BLO 5KFT...BUT DIMINISHING WINDS AND MOST OF THE CONVECTIVE LAYER WITHIN THE DGZ WILL STILL BOOST SNOW AMOUNTS. EXPECT SNOW TOTALS TODAY INTO THIS EVENING OF 2 TO 4 INCHES AND ANOTHER 1 TO 3 INCHES LATER THIS EVENING INTO THE OVERNIGHT. UPDATED WSW STATEMENT ALREADY OUT. COORD WITH APX ON THE LAKE EFFECT SNOW ADVISORY FOR LUCE COUNTY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 546 AM EST THU JAN 1 2015 THE STACKED SFC-500MB LOW OVER S HUDSON BAY WILL WEAKEN SLIGHTLY AND DRIFT OVER N QUEBEC OVERNIGHT TONIGHT. THIS WILL KEEP THE UPPER GREAT LAKES IN NW FLOW ALOFT WITH SEVERAL SMALL WAVES SHIFTING ACROSS THE AREA. A DOMINANT SFC TROUGH/COLD FRONT HOVERING NEAR THE N MN BORDER WILL SINK ACROSS UPPER MI THROUGH THE DAY TODAY. THIS...AND AN SHORTWAVE PUSHING ACROSS THE AREA WILL ALLOW FOR SOME INTENSIFICATION TO SNOW SHOWERS THIS AFTERNOON. AS A RESULT...WILL KEEP THE HIGH CHANCE POPS GOING ACROSS THE AREA AROUND 18Z...BEFORE DIMINISHING THEM AGAIN TO ALONG THE LAKE SUPERIOR SHORELINE THIS EVENING. 850MB TEMPS WILL FALL FROM THE MORNING READINGS OF -12 TO -15C TO -18 TO -21C BY DAYBREAK FRIDAY. AS FOR SPECIFICS... LES CONTINUES ACROSS THE KEWEENAW PENINSULA...WITH A DOMINANT BAND STRETCHING ACROSS LAKE SUPERIOR TO NEAR WHITEFISH POINT. LOOK FOR THE EASTERN LAKE SUPERIOR BAND TO SLOWLY SINK S ONSHORE AS THE CONVERGENT W TO SW WINDS KEEPING IT JUST OFF THE SHORE RELAX AND NW WINDS OFF THE LAKE WIN OUT LATER THIS MORNING. THIS WILL PUSH THE BAND OVER N LUCE COUNTY...WITH 1-3 INCHES OF SNOW FCST FOR MUCH OF LUCE COUNTY. ANOTHER 1-3 INCHES IS EXPECTED TONIGHT WITH BETTER CONVERGENCE NEAR WHITEFISH POINT. WILL KEEP THE LES ADVISORY FOR SNOW AND BLOWING/DRIFTING SNOW GOING ACROSS THE KEWEENAW PENINUSLA. EXPECT ANY DOMINANT BANDS...HIGHER SNOW AMOUNTS...TO DRIFT AROUND AND S OF CMX...WITH NEW SNOW TODAY OF 1-3 INCHES. EXPECT ANOTHER COLD NIGHT...WITH LOWS GENERALLY IN THE SINGLE DIGITS BELOW AND ABOVE ZERO...WARMEST WHERE CLOUDS AND SNOW SHOWERS LINGER ALONG LAKE SUPERIOR. .LONG TERM...(FRIDAY THROUGH WEDNESDAY) ISSUED AT 501 AM EST THU JAN 1 2015 PERSISTENT RIDGING OVER THE EASTERN PACIFIC/NAMERICA WEST COAST REGION WILL MAINTAIN A BROAD UPPER TROUGH OVER MUCH OF CANADA AND THE GREAT LAKES REGION THROUGH THE FIRST WEEK OF JANUARY RESULTING IN BELOW NORMAL TEMPERATURES AND PERIODS OF LAKE EFFECT SNOW FOR UPPER MI. BEGINNING FRIDAY...MODEL CONSENSUS SUGGESTS WINDS WL BACK MORE WESTERLY AGAIN AS SFC RDG AXIS ADVANCES ACROSS AREA FROM THE NRN PLAINS. THE GENERALLY WEAK WRLY FLOW ALONG WITH ENHANCED LOW-LVL CONVERGENCE FROM LAND BREEZES WL HELP FOCUS GENERALLY LIGHT LAKE EFFECT SNOW ACROSS THE KEWEENAN PENINSULA AND THE FAR ERN SHORELINE OF THE CWA AS INVERSION BASES CRASH BLO 5KFT WITH DRY AIR NOTED BENEATH THE INVERSION. SINCE MUCH OF THE DGZ IN STILL WITHIN THE CLOUD LAYER...LES BANDS COULD YIELD 1-2 INCHES OF FLUFFY ACCUMULATION DURING THE DAY. WAA CLOUDS AHEAD OF SHORTWAVE MOVING IN FROM THE NRN PLAINS WILL LIMIT RADIATIONAL COOLING FRIDAY NIGHT BUT TEMPS SHOULD STILL APPROACH ZERO OR MAYBE EVEN DIP BLO ZERO AT A FEW OF THE TYPICAL COLDER LOCATIONS OVER THE WESTERN INTERIOR. THIS WEEKEND...FOCUS IS ON PHASING/INTERACTION OF SPLIT FLOW. TWO FEATURES WILL COME INTO PLAY...ONE WILL BE THE REMNANTS OF A CLOSED LOW NOW PRODUCING SNOW OVER THE SW CONUS...AND THE SECOND IS A NRN BRANCH SHORTWAVE NOW OVER THE ALEUTIAN ISLANDS WHICH IS FCST TO DIVE SE ACROSS THE NRN ROCKIES FRI NIGHT AND THEN THROUGH THE PLAINS STATES ON SAT. ASSOCIATED STRONG MID LEVEL WARM AIR ADVECTION AHEAD OF THIS SHORTWAVE AND ITS ASSOC SFC LOW WILL SPREAD SNOW EAST INTO MAINLY THE NORTHWEST HALF OF THE CWA ON SAT. WHILE THE MODELS STILL PEG THE HEAVIEST SNOW TO OCCUR OVER LAKE SUPERIOR...WILL CONTINUE TO SHOW SOME LIKELY POPS OVER AND AROUND THE KEWEENAW PENINSULA FOR SATURDAY. AS THIS SNOW IS OCCURRING...THE NORTHERN SHORTWAVE WILL CONTINUE TO DIVE SOUTHEAST AND BEGIN TO PHASE WITH THE REMNANTS OF THE SW CONUS UPPER LOW WHICH WILL LEAD TO BOTH FEATURES EJECTING NORTHEAST THROUGH THE LOWER GREAT LAKES REGION SATURDAY NIGHT INTO SUNDAY. THE 00Z ECMWF...GFS AND NAM ALL TRENDING DEEPER AND FARTHER WEST WITH RESULTING SFC LOW WHICH BLEND OF THESE MODELS SHOW A TRACK THROUGH SRN LWR MI TO NEAR GEORGIAN BAY BY 12Z SUNDAY. THE GEM-NH MEANWHILE AFTER SHOWING A SIMILAR TRACK TO THE 00Z ECMWF/GFS BLEND HAS NOW TRENDED FARTHER EAST THROUGH SE LOWER MI INTO ERN ONTARIO. IF THE LATEST GFS/ECMWF SOLNS HOLD TRUE THIS WOULD MEAN A GREATER POTENTIAL FOR SYNOPTIC PCPN TO SPREAD INTO UPPER MI...ESPECIALLY THE EAST HALF...ALONG WITH A GREATER POTENTIAL FOR NORTH FLOW LAKE ENHANCED SNOW ON THE BACKSIDE OF THE SYSTEM. WILL LIKELY NEED TO TREND POPS UPWARD ACROSS THE CWA AND ESPECIALLY ALONG LAKE SUPERIOR ZONES WITH A GREATER POTENTIAL FOR LAKE ENHANCED SNOW SAT NIGHT INTO SUNDAY. WINDS WILL ALSO RAMP UP WITH TIGHTER GRADIENT ON BACKSIDE OF SYSTEM WHICH WILL ALSO RESULT IN MORE BLOWING SNOW. WILL HIGHLIGHT POTENTIAL FOR MODERATE SNOW AND BLOWING SNOW IN HWO...ESPECIALLY ALONG LAKE SUPERIOR AND THE EAST HALF OF THE CWA FOR SAT NIGHT INTO SUNDAY EVENING. LATE SUNDAY NIGHT INTO MONDAY NIGHT...WEAKENING PRES GRADIENT WILL ALLOW WINDS TO DIMINISH ESPECIALLY OVER THE INTERIOR. WINDS WILL ALSO BE BACKING MORE WESTERLY ESPECIALLY BY MONDAY IN ADVANCE OF STRONG SFC HIGH PRES RDG BUILDING IN FROM THE NRN PLAINS...SO EXPECT LES TO EVENTUALLY BECOME MORE CONFINED TO KEWEENAW AND FAR ERN SHORELINE AREAS OF THE CWA MONDAY AFTERNOON INTO MON NIGHT. WITH HEART OF COLDEST AIR (850 MB TEMPS OF -26 TO -28C) COMING ACROSS THE UPPER LAKES...EXPECT VERY COLD TEMPS SUN NIGHT AND MONDAY. EXPECT MUCH OF THE INTERIOR CWA TO FALL BLO ZERO AND WOULD NOT BE SURPRISED TO SEE SOME WESTERN INTERIOR LOCATIONS FALL WELL INTO THE TEENS BLO ZERO... ESPECIALLY ALONG THE WI BORDER. HIGHS MONDAY WILL REMAIN VERY COLD WITH READINGS RANGING FROM THE SINGLE DIGITS BLO ZERO WESTERN INTERIOR TO THE SINGLE DIGITS ABV ZERO EAST AND ALONG THE GREAT LAKES. TUESDAY INTO WEDNESDAY...MODELS IN REASONABLY GOOD AGREEMENT SHOWING ANOTHER CLIPPER SHORTWAVE MOVING ACROSS THE UPPER GREAT LAKES ON TUESDAY WITH ANOTHER REINFORCING SHOT OF ARCTIC AIR (8H TEMPS FALL AGAIN TO -28C TO -30C) AS WINDS VEER TO THE NW. THIS WILL BRING LES FARTHER INLAND AGAIN AFFECTING THE NRN TIER AND ERN HALF COUNTIES FROM LATE TUE THROUGH WED. LOOK LIKE ONLY THE FAR SOUTH CENTRAL WOULD ESCAPE THE LES. WITH SUCH A COLD ARCTIC AIRMASS FCST THE DGZ WILL GET SQUASHED NEAR THE LAKE SFC WHICH WILL LIKELY RESULT IN SMALLER FLAKE SIZE. THIS WILL LIMIT LES ACCUMULATION BUT AT SAME TIME WILL BE MORE EFFECTIVE FOR REDUCING VSBY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 739 AM EST THU JAN 1 2015 A COLD FRONT ACROSS THE AREA WILL HELP KEEP SNOW SHOWERS GOING AT ALL 3 SITES. REDUCED VIS DOWN TO LIFR AND IFR WILL REMAIN AT IWD UP THROUGH CMX...GIVEN THE FAVORABLE W WINDS THAT WILL BE BECOME MORE NORTHWESTERLY BY LATE MORNING/EARLY AFTERNOON. REMAINED MOST PESSIMISTIC FOR CMX AS SOUNDINGS INDICATE LOW LEVEL MOISTURE TRAPPED BELOW 5KFT THROUGH THE END OF THE PERIOD. BLSN WILL SLOWLY COME TO AN END TODAY AS THE STRONG LOW RESPONSIBLE FOR THE STRONG WINDS DIMINISHES AND EXITS HUDSON BAY INTO QUEBEC. LOOK FOR VFR CEILINGS TO RETURN BEHIND THE SFC TROUGH BY 01Z FRIDAY IF NOT EARLIER...AND END BY AROUND 05Z /OR POSSIBLY A BIT LATER/ AT IWD AS SFC WINDS BECOME MORE OUT OF THE W...WITH THE MAIN BANDS OF LAKE EFFECT SNOW SHIFTING N OF THE SITE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 412 AM EST THU JAN 1 2015 A LOW OVER S HUDSON BAY WILL SHIFT INTO N QUEBEC FRIDAY MORNING. THE TROUGH EXTENDING FROM THIS LOW ACROSS LAKE SUPERIOR WILL SLOWLY WEAKEN. AS A RESULT...EXPECT THE GALES OF 35-40KTS TO SLOWLY DIMINISH TOO. WHILE HEAVY FREEZING SPRAY HAS DIMINISHED THIS MORNING...IT WILL PICK UP AGAIN OVER N LAKE SUPERIOR THIS AFTERNOON-EVENING. HIGH PRESSURE SINKING ACROSS MINNESOTA THIS EVENING WILL STRETCH FROM THE GREAT LAKES THROUGH THE OHIO VALLEY ON FRIDAY...AND EXIT TO SOUTHERN QUEBEC AND THE NEW ENGLAND STATES FRIDAY NIGHT. EXPECT A LOW ACROSS THE DAKOTAS FRIDAY NIGHT TO CONSOLIDATE WITH AN ADDITIONAL LOW ACROSS THE MISSISSIPPI VALLEY. THE NEW LOW WILL MOVE NE AND DEEPEN ACROSS LOWER MICHIGAN AND LAKE HURON SATURDAY NIGHT...AND EXIT S QUEBEC ON SUNDAY. THIS WILL BRING A TROUGH SATURDAY NIGHT INTO SUNDAY FOR LAKE SUPERIOR. N-NW GALES OF 35 TO NEAR 40KTS WILL AGAIN BE POSSIBLE SUNDAY INTO SUNDAY EVENING. BY MONDAY...A RIDGE WILL SETTLE ACROSS THE N PLAINS AND UPPER MISSISSIPPI VALLEY. HEAVY FREEZING SPRAY WILL ALSO RETURN AS A COLD RIDGE WILL SETTLE ACROSS THE N PLAINS AND UPPER MISSISSIPPI VALLEY MONDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ001-003. LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ006- 007-085. LAKE SUPERIOR... GALE WARNING UNTIL 6 PM EST THIS EVENING FOR LSZ266-267. HEAVY FREEZING SPRAY WARNING UNTIL 3 AM EST FRIDAY FOR LSZ263- 264. LAKE MICHIGAN... NONE. && $$ UPDATE...JLA SHORT TERM...KF LONG TERM...VOSS AVIATION...KF MARINE...KF
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
423 PM CST Thu Jan 1 2015 .SHORT TERM: (Tonight and Friday) Issued at 338 PM CST Thu Jan 1 2015 The area is sandwiched between high pressure to the south and a trof of low pressure up across the Upper Midwest. Southwest flow is the result and temperatures have rebounded into the mid and upper 30s across the entire area. With abundant cloud cover and weak southwest flow continuing tonight, expect that lows tonight will be several degrees warmer tonight than they were last night. Most areas should get back down below freezing again, but think temps should stay mostly in the upper 20s to low 30s across the majority of the area (with the exception of northern MO and west central IL where clouds should be thinner allowing for more radiational cooling). NAM, GFS, and RAP develop some weak moisture convergence on the 850mb baroclinic zone Friday morning just south of the STL Metro area. While the GFS says dry, the NAM and to a lesser extent the RAP do print out a little very light QPF. 4km NCEP and NSSL WRF models also show very light QPF Friday morning, and light simulated radar returns as well. Therefore, feel there`s enough signal to bump up PoPs slightly for Friday morning along and southeast of I-44/US-50. P-types will likely start out as a little rain/sleet mix and where temps are below freezing there could be a bit of glaze, but amounts look very light. Precip should turn quickly to light rain or just sprinkles with a couple of hours of sunrise, and highs look to be in the mid to upper 30s across the area on Friday. Carney .LONG TERM: (Friday Night through Next Thursday) Issued at 421 PM CST Thu Jan 1 2015 Models are coming into better consensus with the storm system for Friday night and Saturday. GFS and NAM continue to warm up bit by bit. Most recent partial thickness forecasts show all critical thickness lines for rain/snow well up into northern Missouri/southern Iowa by the time the precipitation starts on Friday night. Forecast soundings also have little or no cold layer in the low levels indicating that sleet is becoming less and less likely. So have more or less confined any chances of sleet to northern zones Friday evening, changing over to all rain and freezing rain where surface temperatures dictate. Think any accumulations of freezing rain will be minor due to warm ground temperatures and diabatic warming due to latent heat release. Temperatures should warm above freezing after sunrise on Saturday morning at any rate which should stop any ice accumulation. Think the greatest amount of accumulation will be over northern MO and west central IL and amounts should be between a trace and 0.05 inch. Dry slot should wrap around into the storm on Saturday afternoon which will likely make the rain slack off and even end across southern portions of the area. Cold front moves through Saturday evening with the tail end of the def-zone clipping our area. Guidance seems to want to keep the majority of the QPF out of our area over northwest Missouri and southern Iowa. However, it looks like our northwest counties could get clipped with an inch or two of snow before all the shouting is over. Remainder of the forecast looks cold and dry as a longwave trof deepens over the eastern CONUS. This will allow a couple of Arctic air intrusions into the lower 48...one on Sunday and Monday behind the weekend storm, and another midweek. This should keep temperatures well below normal through the end of the forecast period. Carney && .AVIATION: (For the 18z TAFs through 18z Friday Afternoon) Issued at 1142 AM CST Thu Jan 1 2015 General thickening and lowering cloud deck trend is expected over the next 30 hours as southerly flow continues in the lower atmosphere. Have not introduced precipitation into the forecast at this time as the majority is forecast to remain south of the terminals. That being said, a few models are showing some light QPF edging toward the St. Louis Metro terminals early tomorrow morning. Depending on surface temperature this could be DZ or FZDZ if it occurs. Am not confident enough in this occuring to include into the forecast at this time. Light southwest to south wind expected to continue. Specifics for KSTL: Only concern is for light drizzle or freezing drizzle early Friday morning. Confidence too low at this point to include in the forecast - but something to keep an eye on. Otherwise, general thickening and lowering cloud trend is forecast with a light southwest wind. CVKING && .PRELIMINARY POINT TEMPS/POPS: Saint Louis 29 38 34 41 / 10 20 80 90 Quincy 23 34 29 35 / 5 5 50 80 Columbia 27 37 31 38 / 10 10 80 80 Jefferson City 28 38 32 40 / 10 10 80 80 Salem 29 37 33 43 / 10 10 80 90 Farmington 30 38 33 43 / 20 20 80 90 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
339 PM CST Thu Jan 1 2015 .SHORT TERM: (Tonight and Friday) Issued at 338 PM CST Thu Jan 1 2015 The area is sandwiched between high pressure to the south and a trof of low pressure up across the Upper Midwest. Southwest flow is the result and temperatures have rebounded into the mid and upper 30s across the entire area. With abundant cloud cover and weak southwest flow continuing tonight, expect that lows tonight will be several degrees warmer tonight than they were last night. Most areas should get back down below freezing again, but think temps should stay mostly in the upper 20s to low 30s across the majority of the area (with the exception of northern MO and west central IL where clouds should be thinner allowing for more radiational cooling). NAM, GFS, and RAP develop some weak moisture convergence on the 850mb baroclinic zone Friday morning just south of the STL Metro area. While the GFS says dry, the NAM and to a lesser extent the RAP do print out a little very light QPF. 4km NCEP and NSSL WRF models also show very light QPF Friday morning, and light simulated radar returns as well. Therefore, feel there`s enough signal to bump up PoPs slightly for Friday morning along and southeast of I-44/US-50. P-types will likely start out as a little rain/sleet mix and where temps are below freezing there could be a bit of glaze, but amounts look very light. Precip should turn quickly to light rain or just sprinkles with a couple of hours of sunrise, and highs look to be in the mid to upper 30s across the area on Friday. Carney .LONG TERM: (Tonight through Wednesday) Issued at 345 AM CST Thu Jan 1 2015 (Tonight through Saturday) The approaching system to impact the region thru the weekend continues to be the forecast focus. The upper low, currently over the swrn U.S., shud have been well sampled last evening which increases confidence in the latest mdl guidance. However, with differences among mdl solns, that confidence is reduced. A quick note that the 00z GFS soln has dewpoint initialization problems once again. This time, it appears the bad data is washed out within 18 to 24 hrs, at least in this region. Otherwise, mdls are in good agreement thru 12z Fri. However, differences quickly emerge beyond this time. The NAM/local WRF are a fast soln, with the GEM being a slow soln and the ECMWF/GFS/GEFS between these extremes tho still not in agreement with one another. Have trended twd the ECMWF/GFS/GEFS solns thru this period. These solns seem most logical given the timing and placement of the upstream jet. Overall, main forecast changes are precip onset quicker as well as warmer temps. Mdls have a more shallow cold air wedge N of the wrmfnt as the system approaches. Have therefore trended p-types twd a RA vs. FZRA and reduced mention of IP. However, the nwd advancement of the wrmfnt slows greatly Fri night into Sat. Have kept mention of IP across nrn portions of the CWA during this time where the cold air shud be deep enuf for precip to refreeze. The warm air aloft is also colder during this time so cold air shud not need to be as deep. The ECMWF/GFS/GEFS have shifted the def zone precip further to the NW on Sat night. The best chances for SN now appear to stretch from KC to ern IA, just to the NW of the CWA. However, nrn and ern portions of the CWA will likely see some SN as the def zone pulls newd thru the region. Uncertainty with the placement of this precip still exists and will continue until mdl solns are more consistent. (Sunday through Wednesday) Precip will have ended by the beginning of this period and therefore, focus turns to temps thru the extd. The ECMWF/GFS/GEFS remain in fairly good agreement thru the end of the forecast period. Have therefore trended the forecast twd a compromise thru the extd. Cannot rule out a chance for precip sometime Mon night into Tues and/or Wed. Since these systems are clippers, determining the location of precip as the s/w drops thru the region will be difficult and have low confidence in any one soln. Have kept PoPs low for now. Tilly && .AVIATION: (For the 18z TAFs through 18z Friday Afternoon) Issued at 1142 AM CST Thu Jan 1 2015 General thickening and lowering cloud deck trend is expected over the next 30 hours as southerly flow continues in the lower atmosphere. Have not introduced precipitation into the forecast at this time as the majority is forecast to remain south of the terminals. That being said, a few models are showing some light QPF edging toward the St. Louis Metro terminals early tomorrow morning. Depending on surface temperature this could be DZ or FZDZ if it occurs. Am not confident enough in this occuring to include into the forecast at this time. Light southwest to south wind expected to continue. Specifics for KSTL: Only concern is for light drizzle or freezing drizzle early Friday morning. Confidence too low at this point to include in the forecast - but something to keep an eye on. Otherwise, general thickening and lowering cloud trend is forecast with a light southwest wind. CVKING && .PRELIMINARY POINT TEMPS/POPS: Saint Louis 29 38 34 41 / 10 20 80 90 Quincy 23 34 29 35 / 5 5 50 80 Columbia 27 37 31 38 / 10 10 80 80 Jefferson City 28 38 32 40 / 10 10 80 80 Salem 29 37 33 43 / 10 10 80 90 Farmington 30 38 33 43 / 20 20 80 90 && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1140 AM EST THU JAN 1 2015 .SYNOPSIS... HIGH PRESSURE ACROSS THE SOUTHEASTERN U.S. WILL MOVE OFFSHORE FRIDAY. RAIN CHANCES WILL INCREASE FRIDAY...WITH PERIODS OF RAIN EXPECTED FRIDAY NIGHT AND SATURDAY AS A WARM FRONT APPROACHES. A STRONG COLD FRONT MAY BRING A FEW THUNDERSTORMS SUNDAY AFTERNOON AND NIGHT. CLEAR AND COLD CONDITIONS WILL OVERSPREAD THE CAROLINAS MONDAY THROUGH WEDNESDAY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM THURSDAY...VERY FEW CHANGES WERE NEEDED TO THE FORECAST. SKIES ARE CLEAR WITH SATELLITE IMAGERY INDICATING CIRRUS NOW APPROACHING THE SOUTHERN APPALACHIANS WILL BEGIN TO REACH THE COAST THIS AFTERNOON. 12Z SOUNDINGS FROM MHX AND GSO LOOKED MUCH LIKE THE 06Z MODELS INDICATED. BASED ON RECENT HRRR AND RUC MODELS I HAVE INCREASED ONSHORE WINDS BY A FEW MPH THIS AFTERNOON NEAR THE BEACHES WITH A WEAK SEABREEZE CIRCULATION. THIS ONSHORE WIND WILL ALSO UNFORTUNATELY DRAG SOME PRETTY CHILLY AIR BACK IN FROM THE OCEAN DURING THE MID-AFTERNOON HOURS. INLAND HIGHS SHOULD RANGE FROM 54-57...WITH THE BEACHES RUNNING A FEW DEGREES COOLER. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM THURSDAY...FOR THE MEDIUM AND LONG RANGE PACKAGE WILL FAVOR THE GFS/ECMWF SOLUTION FOR THE PERIOD. H5 CUT OFF LOW ACROSS THE SW RESULTS IN SPLIT FLOW ACROSS THE CONUS WITH RIDGING ACROSS THE GULF COAST AND SE THROUGH THE PERIOD. EXPECT CLOUDS TO STREAM INTO THE AREA AND THICKEN ON FRIDAY WITH PRECIPITATION CHANCES INCREASING AS GULF MOISTURE BECOMES AVAILABLE. BELIEVE THE FIRST HALF OF THE DAY SHOULD REMAIN DRY WITH CHANCE POPS DURING THE LATER HALF OF FRIDAY. MAIN BULK OF PRECIPITATION STAYS TO OUR WEST AS H5 LOW AND SURFACE LOW TRACK TO THE NE . H8 LOW LEVEL JET INCREASE TO 30-35 KNOTS ACROSS THE REGION INCREASING LOW LEVEL INSTABILITY AS EXIT REGION OF JET MOVES ACROSS THE CWA LATE SATURDAY. WITH H5 SW FLOW WILL LOOK FOR MODERATING TEMPERATURES THROUGH THE PERIOD. MOST OF THE PRECIPITATION WILL BE ON THE LIGHT SIDE FRIDAY INTO SATURDAY WITH BREAKS THROUGHOUT THE PERIOD. WILL STAY CLOSE TO GUIDANCE TEMPS FOR THE PERIOD. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 300 AM THURSDAY...EXPECT SUNDAY TO BE THE MORE ACTIVE DAY OF THE WEEKEND WITH THE SPLIT FLOW PATTERN ACROSS THE US PHASING IN ACROSS THE EASTERN HALF OF THE COUNTRY DURING THIS PERIOD AS H5 LOW AND SURFACE LOW MOVE INTO THE GREAT LAKES WITH DEVELOPING TROUGH ACROSS THE CENTRAL U.S. H5 SW FLOW ACROSS THE SE WITH ABOVE NORMAL TEMPERATURES EXPECTED ON SUNDAY AND THE GREATER RISK OF RAIN AND POSSIBLE THUNDERSTORMS AHEAD OF ADVANCING COLD FRONT MOVING INTO THE CAROLINAS. MODELS PEG THE FRONT ACROSS THE CWA DURING LATE AFTERNOON INTO THE EARLY EVENING WITH BEST DYNAMICS AT THIS TIME TO SUPPORT SOME ELEVATED CONVECTION AIDED BY DEPARTED H8 JET STREAK ACROSS THE REGION. WILL MAKE MENTION OF SLIGHT CHANCE OF TSTM IN THE GRIDS FOR THE AFTERNOON/EVENING PERIOD. AS THE FRONT EXITS THE COAST LATE SUNDAY AND H5 FLOW DAMPENS OUT BECOMING MORE ZONAL FOR NEXT WEEK EXPECT SEASONABLE TO SLIGHTLY ABOVE CLIMO TEMPS FOR NEXT WEEK FOR THE HIGHS AND CLEAR BUT COOLER OVERNIGHT LOWS BELOW SLIGHTLY BELOW CLIMO AS CANADIAN HIGH PRESSURE BUILD IN FORM THE WEST BUT STAYS TO OUR NORTH. GFS SEEMS TO WANT TO DEVELOP A SURFACE LOW OFF THE SE COAST LATE IN THE PERIOD BUT ITS FURTHER EAST THEN THE 31/00Z RUN OF LAST NIGHT AND WEAKER. THE ECMWF HAS NOT HAD THIS FEATURE DURING THE PAST FEW RUNS SO WITH HE GFS TRENDING WEAKER AND FURTHER EAST IT WILL NOT IMPACT THE REGION TUESDAY INTO WEDNESDAY. H5 FLOW BECOMES MORE NW TOWARDS THE END OF THE PERIOD AND WE START TO SEE COOLER TEMPS ARRIVE BY THURSDAY INTO FRIDAY. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... AS OF 18Z...WEAK HIGH PRESSURE WILL SHIFT OFFSHORE TODAY...WITH MAINLY WEAK SOUTHWESTERLY FLOW THIS AFTERNOON. THIS EVENING...INCREASING CLOUDINESS AS THE NEXT SLUG OF MOISTURE RIDES UP FROM THE SOUTHWEST. THE NAM IS A BIT MORE PESSIMISTIC THAN THE GFS...WITH RAIN BEGINNING BEFORE DAYBREAK IN SPOTS. WILL GO WITH MORE OF A BLEND DUE TO THE WEAK ISENTROPIC NATURE OF THINGS. WILL INTRODUCE PRECIP FRIDAY BY MID TO LATE MORNING. CEILINGS AND VISIBILITIES WILL LIKELY REMAIN VFR THROUGH THE END OF THE FORECAST PERIOD...HOWEVER THINGS WILL DETERIORATE SHORTLY AFTER THAT. EXTENDED OUTLOOK...VFR INTO FRI. CHANCE OF RAIN AND MVFR/TEMPO IFR CONDITIONS FRI NIGHT THROUGH SUN. BECOMING VFR LATE SUN. VFR MON AND TUE. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM THURSDAY...VERY FEW CHANGES WERE NEEDED TO THE FORECAST. BASED ON LATEST HRRR AND RUC MODELS I HAVE BUMPED UP WIND SPEEDS BETWEEN 1-5 PM BY A FEW KNOTS NEAR THE BEACHES WITH A WEAK SEABREEZE CIRCULATION. WIND SPEEDS STILL WILL REMAIN LESS THAN 10 KT. SEAS ARE BARELY 1-2 FEET AND SHOULD CHANGE LITTLE THROUGH THE DAY. E THE RULE TONIGHT. SEAS WILL BE 2 FT OR LESS THROUGH THE PERIOD. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 300 AM THURSDAY...WEAK BUBBLE HIGH ACROSS THE COASTAL WATERS DURING FRIDAY WILL RESULT IN RELATIVELY LIGHT WINDS AND SEAS LESS THAN 10 KT WITH SEAS 1-2 FEET NEAR SHORE AND 2-3 OFFSHORE. SATURDAY THE WINDS INCREASE FROM THE EAST AS COASTAL TROUGH OFFSHORE INTERACTS WITH THE FRONT TO UR WEST IN TIGHTENING THE PRESSURE GRADIENT ACROSS THE WATERS. BY MID DAY SATURDAY EAST WINDS OF 10-15 KTS NEAR SHORE AND 15-20 KTS OFFSHORE WILL START TO BUILD SEAS TO 2-4 NEAR SHORE AND 3-5 FEET OFFSHORE APPROACHING 6 FEET IN THE OUTER MARINE ZONES BY LATE SATURDAY. LONG TERM /SUNDAY THROUGH MONDAY/... AS OF 300 AM THURSDAY...SMALL CRAFT ADVISORY CONDITIONS ARE POSSIBLE SUNDAY AND MAYBE MONDAY AS FRONT APPROACHES THE COASTAL WATERS AND WINDS VEER TO THE SW AND INCREASE TO 15-20 KTS NEAR SHORE AND 20 TO 25 KTS OFFSHORE WITH BUILDING SEAS. WITH H8 JET STREAK EXITING THE AREA AND THREAT OF ISOLATED THUNDERSTORMS SEAS SHOULD REACT AND BUILD QUICKLY ON SUNDAY AND BE CHOPPY. FRONT PASSES ACROSS THE COASTAL WATERS LATE SUNDAY NIGHT EARLY MONDAY AND WINDS BECOME NORTHWEST STILL RATHER STRONG AT 15-20 KTS WILL KEEP SEAS UP FOR THE EARLY PART OF MONDAY BEFORE SUBSIDING A BIT BY AFTERNOON BUT NOT BY MUCH. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...RJD/TRA SHORT TERM...MAC LONG TERM...MAC AVIATION...43
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
324 PM CST THU JAN 1 2015 .SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT) ISSUED AT 324 PM CST THU JAN 1 2015 FORECAST CHALLENGES FOR SHORT TERM WILL BE OVERNIGHT LOWS TONIGHT FOLLOWED BY EVOLUTION OF A SNOW PRODUCING CLIPPER SYSTEM TOMORROW NIGHT...TO INCLUDE SNOW AMOUNTS AND INTENSITIES MAINLY AFTER MIDNIGHT INTO SUNDAY MORNING. THE ECMWF/GEM/GFS HAVE THE BEST AGREEMENT FOR THIS SYSTEM AND WILL USE A ECMWF/GFS BLEND. TONIGHT...CURRENT VIS SHOWS SOME CLEARING OVER PORTIONS OF THE DEVILS LAKE BASIN AS WELL AS FRESH SNOW ACROSS PORTIONS OF NORTHEAST ND AND THE NORTHERN RED RIVER VALLEY. MID CLOUD UPSTREAM IN THE NW FLOW MAY ADVECT BACK INTO THE FAR NW AND TIMING OF THIS CLOUD COVER WILL BE CRITICAL ON OVERNIGHT LOWS...AS WELL AS ONSET OF RETURN FLOW ACROSS EASTERN ND BY MIDNIGHT. A WEAK LOW WILL SKIRT THE NORTH TONIGHT...AND BRINGS SOME LIGHT SNOW TO THE NORTHERN FORECAST AREA FROM MIDNIGHT THROUGH MID MORNING TOMORROW. VERY LIGHT ACCUMULATIONS ARE EXPECTED. MEANWHILE...A CLIPPER WILL DEVELOP ON THE LEE SIDE OF THE NORTHERN/CANADIAN ROCKIES. EXPECT COLDEST TEMPERATURES OVER THE NORTHEASTERN FCST AREA ESPECIALLY THE NORTHERN VALLEY WHERE SKIES SHOULD REMAIN CLEAR ENOUGH TO GET EARLY LOWS BEFORE WARM ADVECTION BEGINS BY MORNING. TOMORROW...CLIPPER SYSTEM BEGINS TO DROP INTO MT AND MOVE EAST...NEARING THE ND STATE LINE AROUND 00Z. A WARM FRONTAL BNDRY WILL LIFT NORTH AND HELP GENERATE SNOW MAINLY IN W AND CNTRL ND ALONG THE INTL BORDER. MODELS DIFFER ON EASTWARD EXTEND OF SNOW...WITH GEM/ECMWF/GFS REACHING THE NORTHERN VALLEY BY 00Z AND THE NAM SLOWER AND DRIER IN THE AFTN HOURS. FOR THIS PERIOD ONLY...LIKE THE SLOWER NAM AS IT WILL TAKE A WHILE TO SATURATE THE COLUMN GIVEN THE DRY AIRMASS IN PLACE FROM NE FLOW TODAY AND TONIGHT. SHOULD SEE SOME DEVELOPMENT IN NORTHEASTERN ND IN THE 21Z TO 00Z SATURDAY TIME FRAME. TOMORROW NIGHT...WELL ADVERTISED CLIPPER SYSTEM WILL MOVE ACROSS CWA...HOWEVER EXACT TRACK OF SFC LOW STILL IN QUESTION. GENERALLY THE SLIGHTLY SOUTHWARD GFS/ECMWF/GFS SOLUTION IS PREFERRED OVER THE MORE NORTHERN NAM SOLUTION...ALTHOUGH ALL MODELS TRENDED NORTH SINCE YESTERDAYS RUN. AN RIGHT ENTRANCE REGION WILL SET UP GENERALLY OVER SOUTHEASTERN MANITOBA AS THE SFC LOW MOVES INTO EASTERN DAKOTAS AFT MIDNIGHT SAT NIGHT. MODELS ARE SHOWING DECENT ISENTROPIC LIFT AS WELL AS H300 TO H500 Q VECTOR CONVERGENCE OVER PORTIONS OF NORTHEASTERN ND AND NORTHWEST MN. THESE INGREDIENTS ARE BEST OVERLAPPED IN SOUTHEASTERN MB AND PORTIONS OF THE NE CWA AND SHOULD HAVE SUFFICIENT ASCENT TO CREATE BANDED SNOWFALL. DID INCREASE GFS-BASED SNOW RATIOS TO AROUND 25:1 IN THE FAR NE. EXPECT TO SEE SOME AREAS OF HEAVY SNOWFALL ACROSS THE NORTH...BUT STILL ENOUGH UNCERTAINTY ON EXACT COUNTIES TO HOLD OFF ON UPGRADING HEADLINES TO A HEAVY SNOW WARNING AS MAIN IMPACTS WILL BE IN THE THIRD PERIOD. IN GENERAL...OVER SIX INCHES OF SNOW IS QUITE POSSIBLE IN COUNTIES ALONG THE INTERNATIONAL BORDER...WITH HEAVIER SNOWFALL BEGINNING AFTER MIDNIGHT AND INCREASING THROUGH MID MORNING SATURDAY. .LONG TERM...(SATURDAY THROUGH THURSDAY) ISSUED AT 324 PM CST THU JAN 1 2015 SATURDAY...CLIPPER WILL TRACK INTO THE LOWER GREAT LAKES AND WRAP AROUND SNOWFALL SHOULD EXIT EASTERN ZONES BY OOZ SUNDAY. MOST SIGNIFICANT ISSUE SATURDAY WILL BE INCREASING WINDS DUE TO TIGHT PRESSURE GRADIENT FROM DEPARTING LOW AND STRONG COLD ADVECTION AS ARCTIC AIR POURS IN TO REGION. THIS WILL GENERATE AREAS OF BLOWING SNOW IN NORTHEASTERN ND BY NOONTIME SATURDAY. THE SOUTHWARD EXTEND OF ANY BLOWING SNOW WILL BE DEPENDENT ON PLACEMENT OF ANY NEW SNOW...WITH MOST FRESH SNOW FALLING NORTH OF THE HWY 200 CORRIDOR AND THE HEAVIEST NORTH OF HWY 2. AGAIN...STILL SOME UNCERTAINTY ON THE TRACK OF THE SFC LOW AND PLACEMENT OF SNOWFALL...BUT BLOWING SNOW COULD BE AN ISSUE IN AT LEAST NE ND ON SAT AM. SATURDAY NIGHT THROUGH SUNDAY...WINDS WILL TAPER DOWN IN THE SOUTHERN VALLEY BY MID TO LATE SATURDAY EVENING. YET ANOTHER ARCTIC AIR MASS WILL THEN MOVE INTO THE REGION AND CREATE SEVERAL DAYS OF SUB ZERO TEMPERATURES FOR MUCH OF THE FORECAST AREA...WITH SUNDAY HIGHS STRUGGLING TO MAKE IT OUT OF THE TEENS BELOW ZERO ON SUNDAY IN THE NORTH. SUNDAY NIGHT THROUGH THURSDAY...THE WORD FOR THE PERIOD IS COLD. ARCTIC HIGH PRESSURE REMAINS IN PLACE OVER THE NORTHERN PLAINS...WITH A POSSIBLE WEAK SYSTEM MOVING THROUGH MONDAY NIGHT. THE GFS AND ECMWF BRING A WEAK REINFORCING SHORTWAVE THROUGH EARLY IN THE WEEK...WITH A LOW PRESSURE CENTER MOVING JUST TO THE SOUTH OF THE CWA AND PUTTING THE SOUTHERN COUNTIES IN THE GOOD DEFORMATION ZONE. THE GEM ON THE OTHER HAND...IS DRY AND NAEFS PRECIP PROBABILITIES ARE NOT THAT HIGH. THE BLENDED SOLUTION GIVES SOME LOW POPS IN OUR SOUTH AND THAT SEEMS REASONABLE FOR NOW. TEMPERATURES WILL CONTINUE TO REMAIN WELL BELOW SEASONAL AVERAGES WITH MANY PLACES SEEING EVEN HIGHS IN THE NEGATIVE NUMBERS. TEMPS SHOULD BEGIN TO MODERATE TOWARDS THE END OF THE PERIOD AS THERE ARE SIGNS OF HEIGHT RISES AS THE MAIN UPPER TROUGH PULLS EAST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 143 PM CST THU JAN 1 2015 TAF SITES HAVE ALL GONE VFR WITH CIGS BETWEEN 3000-7000 FT. SAT LOOP SHOWS ACTUAL CLEARING MOVING INTO NORTHWESTERN MN...WHICH SHOULD IMPACT KBJI...KTVF AND KGFK SHORTLY. THE QUESTION WILL BE HOW FAR SOUTH THE CLEARING GOES TODAY. THE RAP HAS A DECENT HANDLE ON CURRENT CONDITIONS AND HAS THE DRYING RUNNING OUT OF STEAM BEFORE REACHING KFAR AND KDVL...SO LEANED TOWARDS THAT SOLUTION. EVEN AS THERE IS SOME CLEARING IT WILL BE SHORT LIVED AS MOISTURE RETURNS EARLY TONIGHT AS SOUTH WINDS BEGIN TO PICK UP AHEAD OF A LOW PRESSURE SYSTEM. FOR NOW HAVE VFR CLOUDS MOVING BACK IN FIRST...THEN ALL SITES GOING BACK DOWN TO MVFR BETWEEN 06Z AND 12Z FRIDAY. SOME GUIDANCE SHOWS LIGHT FOG FORMATION BUT FOR NOW WILL LEAVE OUT REDUCTIONS TO VIS. NORTH WINDS TODAY WILL BECOME LIGHT AND VARIABLE THIS EVENING BEFORE PICKING UP OUT OF THE SOUTH BY THE END OF THE PERIOD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON FOR NDZ006>008-014>016-026-027-054. MN...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON FOR MNZ001-004>009-013>017. && $$ SHORT TERM...SPEICHER LONG TERM...JR/SPEICHER AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
144 PM CST THU JAN 1 2015 .UPDATE... LATEST SFC OBS INDICATE N TO NNE FLOW IS BRINGING IN VERY DRY AIR MASS WITH DEW POINTS AROUND 0 TO 7 F ACROSS MOST OF THE NORTHERN PORTIONS OF CWA...TRANSITIONING QUICKLY TO 15 TO 20 F ALONG AND SOUTH OF THE HWY 200 CORRIDOR. CONSEQUENTLY NOT SEEING ANY REPORTS OF LIGHT SNOW ACROSS NORTHERN SITES WITH THE DRY LOW LYR...WHILE THERE ARE STILL A FEW REPORTS ACROSS OTTER TAIL AND GRANT COUNTIES. ISENTROPIC CHARTS INDICATE CONDENSATION PRESSURE DEFICITS CLIMB QUICKLY BY 18Z...WHICH SHOULD HELP SCOUR OUT REMAINING CLOUD COVER AND PUSH TO THE FAR SOUTHERN VALLEY ANY AFTN CLOUD COVER. WILL REMOVE POPS FOR ALL BUT SE AND E CNTRL ZONES FOR REMAINDER OF MORNING BUT KEEP MENTION OF FLURRIES THROUGHOUT AREAS OF CLOUD COVER. WILL ALSO ADJUST AFTN SKY FOR EXPECTED TRENDS. LOW SUN ANGLE MAKING IT DIFFICULT TO SEE HOW QUICKLY CLEARING LINE IS MOVING...SO MAY NEED TO MAKE FURTHER ADJUSTMENTS AT 19Z UPDATE. UPDATE ISSUED AT 743 AM CST THU JAN 1 2015 HIGH TEMPS TODAY TWEAKED A BIT WITH TIMING OF COLD AIR CURRENTLY MOVING INTO THE AREA. OTHERWISE NO CHANGES MADE AT THIS UPDATE. && .SHORT TERM...(TODAY THROUGH FRIDAY) ISSUED AT 403 AM CST THU JAN 1 2015 UPPER LEVEL TROUGHS OVER THE GULF OF AK AND THE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST FORECAST TO NEARLY PHASE UP OVER THE CENTRAL PLAINS BY THE END OF THE PERIOD. SURFACE LOW FORECAST TO BOMB OUT FROM THE LOWER OH VALLEY INTO THE GREAT LAKE STATES BY THE END OF THE PERIOD. LEE SIDE SURFACE TROUGH TO DEVELOP OVER MT/WY AND WILL MOVE OUT INTO SD BY 12Z SAT. WILL BE LIVING ALONG THE BAROCLINIC ZONE THE NEXT COUPLE DAYS. IN THE MEANTIME QUITE FAST TRANSITIONS WITH WARM AIR TO THE SOUTH AND WEST AND COLD AIR NORTH AND EAST. MODEL SOUNDINGS INDICATED LOWER LAYERS SATURATE QUICKLY THIS MORNING AHEAD OF A COLD FRONT. COLD AIR OVER SOUTHERN CANADA WILL BRUSH THE AREA FOR MAINLY THIS MORNING. WARM ADVECTION WILL QUICKLY RETURN TONIGHT. LIGHT SNOW EXPECTED ACROSS THE AREA THIS MORNING WITH SHORT WAVE/JET STREAK MOVING THROUGH. WILL ADD LIGHT SNOW FOR FRI MORNING WITH WARM ADVECTION AND BAROCLINIC ZONE IN THE AREA. OTHERWISE MORE SIGNIFICANT SNOW EXPECTED TO START FRI AFTERNOON. THROUGH SAT AFTERNOON. POTENTIAL FOR 6 OR MORE INCHES OF SNOW GENERALLY NORTH OF HIGHWAY 2. WILL ISSUE A WINTER STORM WATCH FOR THAT AREA. .LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 403 AM CST THU JAN 1 2015 FOR SUNDAY THROUGH WEDNESDAY...FORECAST AREA IS DOMINATED BY AN UPPER LEVEL TROUGH AND ARCTIC HIGH PRESSURE. 00Z GFS/ECMWF PRETTY SIMILAR IN OVERALL PATTERN THOUGH ECMWF IS A BIT COLDER WITH ARCTIC AIR. COLDEST DAY SUNDAY...SOME CLOUDS AND RISK OF VERY LIGHT SNOW WILL MOVE ALONG THE SOUTH AND NORTH DAKOTA BORDER MONDAY AS A SYSTEM MOVES INTO THE CENTRAL PLAINS PER GFS...BUT ECMWF KEEPS IT WELL SOUTH DUE TO STRONGER HIGH. HIGH PRESSURE AND CONTINUED BELOW NORMAL TEMPS TUES-WED PERIOD. TEMP MODERATION SEEMS LIKELY END OF NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON) ISSUED AT 143 PM CST THU JAN 1 2015 TAF SITES HAVE ALL GONE VFR WITH CIGS BETWEEN 3000-7000 FT. SAT LOOP SHOWS ACTUAL CLEARING MOVING INTO NORTHWESTERN MN...WHICH SHOULD IMPACT KBJI...KTVF AND KGFK SHORTLY. THE QUESTION WILL BE HOW FAR SOUTH THE CLEARING GOES TODAY. THE RAP HAS A DECENT HANDLE ON CURRENT CONDITIONS AND HAS THE DRYING RUNNING OUT OF STEAM BEFORE REACHING KFAR AND KDVL...SO LEANED TOWARDS THAT SOLUTION. EVEN AS THERE IS SOME CLEARING IT WILL BE SHORT LIVED AS MOISTURE RETURNS EARLY TONIGHT AS SOUTH WINDS BEGIN TO PICK UP AHEAD OF A LOW PRESSURE SYSTEM. FOR NOW HAVE VFR CLOUDS MOVING BACK IN FIRST...THEN ALL SITES GOING BACK DOWN TO MVFR BETWEEN 06Z AND 12Z FRIDAY. SOME GUIDANCE SHOWS LIGHT FOG FORMATION BUT FOR NOW WILL LEAVE OUT REDUCTIONS TO VIS. NORTH WINDS TODAY WILL BECOME LIGHT AND VARIABLE THIS EVENING BEFORE PICKING UP OUT OF THE SOUTH BY THE END OF THE PERIOD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON FOR NDZ006>008-014>016-026-027-054. MN...WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY AFTERNOON FOR MNZ001-004>009-013>017. && $$ UPDATE...SPEICHER SHORT TERM...HOPPES LONG TERM...RIDDLE AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS NORMAN OK
1130 AM CST THU JAN 1 2015 .AVIATION... LIGHT RAIN AND FREEZING RAIN WILL CONTINUE ACROSS SOUTHERN AND EASTERN OKLAHOMA THROUGH 00Z FRI. THEREAFTER...MAINLY DRY CONDITIONS EXPECTED THROUGH EARLY FRI MORNING. HOWEVER...MVFR TO IFR CIGS AND VSBYS WILL LIKELY PERSIST FROM KSPS/KLAW TO KCSM/KHBR. WINDS WILL SHIFT AROUND TO THE NORTH EARLY FRI...AND FREEZING DRIZZLE AND FREEZING RAIN WILL BUILD INTO SOUTHWESTERN TERMINALS BY 12Z...SPREADING NORTHWARD THROUGH THE DAY. FREEZING RAIN MAY CHANGE OVER TO RAIN DURING THE AFTERNOON HOURS FRIDAY. && .PREV DISCUSSION... /ISSUED 555 AM CST THU JAN 1 2015/ AVIATION... 01/12Z TAFS...PRIMARILY MVFR/IFR CONDITIONS EXPECTED MOST OF THE FORECAST PERIOD. AREAS OF FREEZING DRIZZLE/FREEZING RAIN EXPECTED TO AFFECT ALL BUT FAR NORTHERN OKLAHOMA TERMINALS...WHERE PRECIP WILL MAINLY BE SNOW THIS MORNING INTO EARLY AFTERNOON. MOST PERSISTENT LIGHT FZDZ/FZRA EXPECTED NEAR AND SOUTH OF KHBR AND KOUN. BREAK IN MOST OF THE PRECIP EXPECTED TOWARD AND AFTER 20-22Z BUT CIGS/VSBY WILL KEEP IFR/MVFR CONDITIONS GOING ALL BUT NORTHERN OKLAHOMA SITES. WIDESPREAD FREEZING/FROZEN PRECIP EXPECTED TO SPREAD OVER REGION JUST AFTER THIS TAF PERIOD AND LASTING MOST OF THE DAY FRIDAY. PREV DISCUSSION... /ISSUED 452 AM CST THU JAN 1 2015/ DISCUSSION... WAVE NUMBER ONE OF PRECIPITATION IS ONGOING ACROSS SOUTHERN OKLAHOMA AND WESTERN TEXAS THIS MORNING. RADAR TRENDS SHOW ENHANCEMENT OF RADAR REFLECTIVITY IN THE TEXAS PANHANDLE. THE CELLULAR STRUCTURE AND ENHANCED REFLECTIVITY SUGGEST THIS IS ASSOCIATED WITH SLEET. BOTH THE HRRR AND RAP SUGGEST THIS WILL CONTINUE TO DEVELOP AND MOVE EASTWARD WITH THE POTENTIAL FOR A WINTRY MIX EVEN NORTH OF I-40 THIS MORNING INTO EARLY AFTERNOON. THEREFORE...DECIDED TO EXPAND THE WINTER WEATHER ADVISORY FARTHER NORTH. WAVE NUMBER ONE WILL EXIT THE AREA LATE AFTERNOON INTO EARLY EVENING. ATTENTION THEN TURNS TO SECOND WAVE OF PRECIPITATION THAT IS ASSOCIATED WITH THE MAIN UPPER LEVEL LOW. A MORE WIDESPREAD PRECIPITATION EVENT IS EXPECTED. PRECIPITATION WILL LIKELY DEVELOP IN WESTERN NORTH TEXAS EARLY FRIDAY MORNING AND LIFT NORTHEASTWARD THROUGH THE DAY FRIDAY. BECAUSE OF THE EARLY ONSET...THERE IS CONCERN OF A SIGNIFICANT ICING EVENT ACROSS WESTERN NORTH TEXAS. THE FORECAST ON FRIDAY WILL DEPEND ON THE EVOLUTION OF THE SFC 32F WETBULB TEMPERATURE. LATEST GUIDANCE SUGGESTS THIS COULD BE VERY CLOSE TO THE I-44 CORRIDOR BY FRIDAY AFTERNOON. OPTED FOR A MIX OF RAIN/FREEZING RAIN ALONG I-44...WITH A FREEZING RAIN/SLEET MIX NORTHWEST AND ALL RAIN SOUTHEAST. A TRANSITION TO SNOW WILL OCCUR LATE FRIDAY INTO SATURDAY AS THE UPPER LEVEL LOW PASSES THROUGH OKLAHOMA. BOTH THE PARALLEL GFS AND ECMWF STILL SUGGEST THERE COULD BE ACCUMULATING SNOW IN NORTHERN OKLAHOMA SATURDAY. THERE IS THE POTENTIAL THERE COULD BE ENOUGH ACCUMULATING SNOW FOR HEADLINES. THE REST OF OKLAHOMA AND WESTERN NORTH TEXAS COULD BE DRY SLOTTED SATURDAY. AFTER COLLABORATION WITH SURROUNDING OFFICES...DECIDED TO HOLD OFF ON ANY HEADLINES FOR FRIDAY AND SATURDAY. NEVERTHELESS...HEADLINES WILL LIKELY BE REQUIRED FOR PARTS OF THE AREA FRIDAY INTO SATURDAY FOR ACCUMULATING ICE AND/OR SNOW. STAY-TUNED! BEYOND SATURDAY...A RATHER COLD DAY IS EXPECTED ON SUNDAY BEHIND THE STORM SYSTEM. TEMPERATURES WILL SLOWLY MODERATE BEFORE ANOTHER COLD FRONT APPROACHES THE REGION AROUND MID-WEEK. THE FORECAST IS DRY BEYOND SATURDAY. MAHALE && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 27 34 31 39 / 20 60 70 30 HOBART OK 24 33 29 40 / 20 50 60 20 WICHITA FALLS TX 29 34 32 43 / 60 80 70 20 GAGE OK 18 33 22 35 / 0 20 40 50 PONCA CITY OK 24 33 30 37 / 10 30 70 40 DURANT OK 32 36 36 46 / 50 80 80 40 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR OKZ012- 013-016>048-050>052. TX...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR TXZ083>090. && $$ 06/84
AREA FORECAST DISCUSSION
NWS TULSA OK
1124 AM CST THU JAN 1 2015 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. CURRENTLY SEEING VFR CONDITIONS ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. HOWEVER...THAT WILL CHANGE OVER THE NEXT FEW HOURS AS CONDITIONS DETERIORATE. WILL SEE IFR CONDITIONS LATER TONIGHT AS LOW CLOUDS AND FOG DEVELOP ACROSS THE AREA. && .PREV DISCUSSION... /ISSUED 942 AM CST THU JAN 1 2015/ DISCUSSION... THE FORECAST FOR TODAY HAS A HUGE BUST POTENTIAL. IT ALL HINGES ON THE LOCATION OF THE FREEZING LINE AND IF THE HRRR QPF PANS OUT. THE FREEZING LINE IS NOW LOCATED ACROSS SOUTHEAST OKLAHOMA INTO WEST-CENTRAL ARKANSAS. HOWEVER...THERE MAY STILL SOME POCKETS OF BELOW FREEZING TEMPERATURES IN THIS AREA. IT IS BASICALLY GOING TO BE RACE BETWEEN THE PRECIPITATION SHIELD AND THE FREEZING LINE...TO DETERMINE THE PRECIPITATION TYPE ACROSS NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON. WILL CONTINUE WINTER WEATHER ADVISORY AS IT IS FOR NOW WITH MAINLY FREEZING RAIN AND SLEET EXPECTED ACROSS NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS THIS AFTERNOON. LIGHT ACCUMULATIONS OF ICE ARE EXPECTED. HOWEVER...TRAVEL IMPACTS CAN BE GREAT WITH EVEN A THIN GLAZE OF ICE. WILL MORE THAN LIKELY SEE MAINLY RAIN ACROSS THE SOUTH WITH PATCHES OF SLEET. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...WINTER WEATHER ADVISORY UNTIL 6 PM THURSDAY FOR OKZ060-OKZ061- OKZ062-OKZ063-OKZ064-OKZ065-OKZ066-OKZ067-OKZ068-OKZ069- OKZ070-OKZ071-OKZ072-OKZ073-OKZ074-OKZ075-OKZ076. AR...WINTER WEATHER ADVISORY UNTIL 6 PM THURSDAY FOR ARZ001-ARZ002- ARZ010-ARZ011-ARZ019-ARZ020-ARZ029. && $$ AVIATION...10
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
214 PM CST THU JAN 1 2015 .DISCUSSION...WEAK HIGH PRESSURE CONTINUES TO COVER MIDDLE TENNESSEE EARLY THIS AFTERNOON WITH A VFR OVERCAST STRATOCU DECK KEEPING A LID ON TEMPERATURES. RADAR MOSAIC SHOWS A LARGE AREA OF MAINLY LIGHT RAIN OVER NORTHERN MS AND EXTREME SW TN, BUT GIVEN LARGE DEW POINT SPREADS STILL IN PLACE ACROSS THE MID STATE, RAIN WILL BE SLOW TO ARRIVE HERE. HRRR DOES SHOW SOME DEVELOPMENT DURING THE EVENING AND OVERNIGHT, WITH MOST OF THE ACTIVITY REMAINING IN THE RELATIVELY WARM AIR OF SOUTHERN MIDDLE TENNESSEE. SCATTERED ACTIVITY MAY DEVELOP ACROSS OUR NORTH BEFORE 12Z, AND UP AGAINST THE KY STATE LINE THIS PRECIPITATION MAY START OFF AS A RA/FZRA OR RA/IP MIXTURE, BUT ACCUMULATIONS ARE NOT EXPECTED. IN THE MEANTIME, A DEVELOPING LOW TO OUR SW WILL COME RACING NE`WD INTO THE OZARKS BY 12Z SATURDAY, BRINGING A WARM FRONT NORTHWARD ACROSS MIDDLE TENNESSEE SO THAT TEMPERATURES SATURDAY MAY WARM INTO THE 60`S OFF THE PLATEAU. MODEL SOUNDINGS DO SHOW SOME ELEVATED INSTABILITY WITH THIS SYSTEM, SO WILL INCLUDE TS IN THE FORECAST FOR SATURDAY AND SATURDAY NIGHT. CAN`T COMPLETELY RULE OUT A THUNDERSTORM OR TWO PRIOR TO 12Z SATURDAY, BUT THE BEST INSTABILITY WON`T OCCUR UNTIL DURING THE DAY, SO WILL LIMIT TS TO DAY 3 ONLY. SPC ALSO HAS US IN A GENERAL THUNDERSTORM AREA ON DAY 3, WITH FROPA OCCURRING BETWEEN 00Z AND 12Z SUNDAY. THERE WILL LIKELY BE SOME LEFTOVER RAIN ON SUNDAY, BUT THEN LOOK FOR DRY WEATHER FROM SUNDAY NIGHT AT LEAST THROUGH THURSDAY. TEMPERATURES NEXT WEEK WILL REMAIN COLDER THAN NORMAL AS WE NEVER DO REALLY ESTABLISH ANY MEANINGFUL RETURN FLOW, SO IT`S GOING TO A COLD WEEK. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 34 41 40 62 / 50 80 100 90 CLARKSVILLE 31 38 37 63 / 40 70 100 100 CROSSVILLE 33 44 43 58 / 60 80 100 80 COLUMBIA 34 44 42 63 / 60 80 100 90 LAWRENCEBURG 33 45 44 64 / 60 90 100 90 WAVERLY 31 41 40 63 / 50 80 100 100 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ ROSE
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1213 PM CST THU JAN 1 2015 .UPDATE... SFC AND SHORT TERM HI RES MODEL ANALYSIS SHOWS THE 32 DEGREE LINE SLOWLY CRAWLING NORTH OF OUR CWA BORDER BY EARLY THIS AFTERNOON. SOME SFC OBS ARE STILL SHOWING AT OR JUST BELOW FREEZING FOR AREAS ALONG THE BORDER AT 18Z. MOST RETURNS ON RADAR ARE EITHER NOT REACHING THE SURFACE OR VERY LIGHT DRIZZLE AT THE MOMENT SO DID NOT WANT TO EXTEND THE WARNING BEYOND 18Z. JUST CAPTURED THE MINOR TRAVEL HAZARDS IN AN SPS FOR THE FIRST COUPLE HOURS OF THE AFTERNOON. OTHERWISE...SOME SMALL ADJUSTMENTS TO THIS AFTERNOON PRECIP CHANCES WERE MADE TO BETTER AGREE WITH NEIGHBORS AND BASED OFF HRRR/WRF INPUT AND REST OF FORECAST PACKAGE LOOKS GOOD THROUGH TONIGHT. TB3 && .PREV DISCUSSION... /ISSUED 1148 AM CST THU JAN 1 2015/ AVIATION... ISENTROPIC LIFT OF A MOIST AIRMASS OVER THE SHALLOW COLD AIRMASS WILL MAINTAIN IFR/LIFR CIGS/VSBYS THIS AFTERNOON THROUGH FRIDAY. PERIODS OF -RADZ AND BR ARE EXPECTED. N TO NE WINDS OF 10 KTS OR LESS WILL PREVAIL...EXCEPT VRBL LESS THAN 5 KTS ALONG RIO GRANDE. PREV DISCUSSION... /ISSUED 714 AM CST THU JAN 1 2015/ UPDATE... PLEASE SEE THE 12Z AVIATION DISCUSSION BELOW. AVIATION... CIGS WILL CONTINUE TO LOWER THROUGHOUT THE DAY AS LIGHT PRECIPITATION CONTINUES TO MOVE FROM SOUTHWEST TO NORTHEAST ACROSS THE REGION. MOST TAF SITES ARE EITHER CURRENTLY IFR OR WILL DROP INTO IFR WITHIN THE NEXT COUPLE OF HOURS. ALL LIQUID PRECIPITATION IS EXPECTED AT OUR TAF SITES AS TEMPERATURES REMAIN ABOVE FREEZING. PREV DISCUSSION... /ISSUED 417 AM CST THU JAN 1 2015/ SHORT TERM (TODAY THROUGH FRIDAY)... LIGHT FREEZING PRECIPITATION CONTINUES OVER THE ADVY AND WARNING AREAS OF THE SRN EDWARDS PLATEAU...HILL COUNTRY AND BALCONES ESCARPMENT. A CLUSTER OF WEAK THUNDERSTORMS CROSSED FROM NRN MEXICO AND LOOKS TO BE PRODUCING A BRIGHT BAND OF WHAT IS PROBABLY SNOW MELTING INTO RAIN AND POSSIBLY A PARTIAL MELT/REFREEZE TO SLEET AND GRAUPEL. THIS CONVECTIVE AREA IS LOSING THE CELLULAR STRUCTURE AND SHOULD CONTINUE TO WEAKEN AS IT LIFTS NE. THUS WILL LEAVE OUT THE MENTION OF THUNDER AND LET NOWCASTS HANDLE WHAT SHOULD BE A SHORT-LIVED EVENT. THE DAYBREAK EMERGENCE OF CONVECTIVE SLEET BAND IS EXPECTED TO TRACK RIGHT ALONG THE EASTERN PART OF THE BALCONES ESCARPMENT. THUS AM HESITANT TO WARM MORNING TEMPERATURE FORECASTS TO MATCH THE CURRENT TRENDS HOLDING ABOVE FREEZING. HI-RES MODELS HAVE KEPT WITH THE CONVECTIVE BANDING AREA FORMING FARTHER NORTH...BUT THE LATEST RUNS OF THE HRRR DEPICT THE ONGOING CONVECTIVE AREA WELL AND SEND IT ACROSS THE AUSTIN METRO AREA AND NW PART OF THE SAN ANTONIO METRO AREA THROUGH DAYBREAK. WHILE THIS CLUSTER OF MODERATE PRECIPITATION COULD LOWER TEMPS TO FREEZING BRIEFLY...EXPECT THE WEAKENING TREND TO ALLOW MOST AREAS IN THE ADVISORY TO HOLD ONTO ABOVE FREEZING TEMPERATURES WITH MORE ISOLATED FROZEN CONDITIONS POSSIBLE AT HIGHER ELEVATIONS. A SECONDARY CONVECTIVE BAND REMAINS IN THE HRRR PICTURE WHICH SHOULD POTENTIALLY ADD TO THE FREEZING RAIN/SLEET MIX OVER THE WARNING AREA AT AROUND DAYBREAK. THUS THE ONGOING WINTER STORM WARNING AND WINTER WEATHER ADVISORY AREA IS THUS CONSIDERED APPROPRIATE AND NO WSW UPDATES ARE PLANNED. THE CONSENSUS MODEL POPULATION OF THE TEMPERATURES IN THE GRIDDED DATA SUGGESTED A QUICK WARM- UP TO ABOVE FREEZING...BUT WE FAVOR A MORE GRADUAL RISE IN THE MORNING PERIOD WHERE ICING HAS OCCURRED. BY NOON...MODEL SOUNDINGS SUGGEST THERE SHOULD BE AMPLE TIME FOR THE WARMING TO HAVE OCCURRED...AS THE FRONTAL INVERSION SHOULD CONTINUE TO BE MODIFIED BY FALLING RAIN AND DRIZZLE. A COLD RAIN REMAINS IN THE PICTURE THROUGH FRIDAY. TEMPERATURES SHOULD BE ALMOST FLAT FROM THIS AFTERNOON THROUGH LATE FRIDAY MORNING BEFORE WARMING INTO THE 40S OVER MOST AREAS LATE FRIDAY. DESPITE THE HIGH POPS BENEATH THE SOLID OVERRUNNING PATTERN...QPF AMOUNTS REMAIN CONSERVATIVE AND GENERALLY BELOW 1/2 INCH. LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... THE EASTWARD EJECTION OF A SLOW MOVING UPPER LOW BRINGS A SLIGHTLY MORE CONVECTIVE ENVIRONMENT TO TX BY FRIDAY EVENING. THE INCREASED POTENTIAL FOR THUNDER TRANSLATES TO SLIGHTLY HIGHER QPF AMOUNTS WITH ANOTHER 1/2 INCH OF RAIN POSSIBLE IN THE FRIDAY NIGHT PERIOD ALONE. MODEL CONSENSUS REMAINS IN GOOD AGREEMENT TO BRING DECREASING CLOUDS AND RAIN CHANCES BY MIDDAY SATURDAY AND PROBABLY THE WARMEST TEMPS OF THE WEEK. THIS IS BECAUSE ANOTHER FRONT ARRIVES BY SUNDAY MORNING. THE ECMWF TRENDED SHARPLY COLDER FROM THIS FRONT WITH A MUCH ENHANCED POLAR TROUGH OVER THE EASTERN US. THE GFS HAS ALSO TRENDED SLIGHTLY COLDER...SO A BLEND OF THESE TWO MODELS LOOKS REASONABLE. AM HESITANT TO BUY INTO THE ECMWF BASED GUIDANCE THAT PROJECTED MIDDLE TEENS OVER THE HILL COUNTRY MONDAY MORNING. THE COLD PATTERN IS SHOWN BY BOTH THE GFS AND ECMWF SOLUTIONS TO BE SHORT-LIVED WITH A PROGRESSIVE ZONAL PATTERN PUSHING AN UPPER RIDGE OVER TX BY MIDWEEK. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 39 38 43 40 59 / 80 90 80 80 30 AUSTIN BERGSTROM INTL AIRPORT 40 37 43 39 58 / 80 90 80 80 30 NEW BRAUNFELS MUNI AIRPORT 41 39 45 42 61 / 70 80 70 80 30 BURNET MUNI AIRPORT 38 35 40 37 57 / 90 90 80 80 20 DEL RIO INTL AIRPORT 41 41 49 41 61 / 40 50 40 50 - GEORGETOWN MUNI AIRPORT 40 36 41 38 56 / 90 90 80 80 30 HONDO MUNI AIRPORT 41 39 47 40 62 / 50 60 50 60 20 SAN MARCOS MUNI AIRPORT 40 38 44 41 59 / 70 80 70 80 30 LA GRANGE - FAYETTE REGIONAL 43 41 47 44 59 / 70 70 80 80 40 SAN ANTONIO INTL AIRPORT 41 39 46 42 61 / 60 80 60 70 20 STINSON MUNI AIRPORT 42 40 46 42 62 / 60 70 60 70 20 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ MESOSCALE/AVIATION...04 SYNOPTIC/GRIDS...03 PUBLIC SERVICE/DATA COLLECTION...12
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1148 AM CST THU JAN 1 2015 .AVIATION... ISENTROPIC LIFT OF A MOIST AIRMASS OVER THE SHALLOW COLD AIRMASS WILL MAINTAIN IFR/LIFR CIGS/VSBYS THIS AFTERNOON THROUGH FRIDAY. PERIODS OF -RADZ AND BR ARE EXPECTED. N TO NE WINDS OF 10 KTS OR LESS WILL PREVAIL...EXCEPT VRBL LESS THAN 5 KTS ALONG RIO GRANDE. && .PREV DISCUSSION... /ISSUED 714 AM CST THU JAN 1 2015/ UPDATE... PLEASE SEE THE 12Z AVIATION DISCUSSION BELOW. AVIATION... CIGS WILL CONTINUE TO LOWER THROUGHOUT THE DAY AS LIGHT PRECIPITATION CONTINUES TO MOVE FROM SOUTHWEST TO NORTHEAST ACROSS THE REGION. MOST TAF SITES ARE EITHER CURRENTLY IFR OR WILL DROP INTO IFR WITHIN THE NEXT COUPLE OF HOURS. ALL LIQUID PRECIPITATION IS EXPECTED AT OUR TAF SITES AS TEMPERATURES REMAIN ABOVE FREEZING. PREV DISCUSSION... /ISSUED 417 AM CST THU JAN 1 2015/ SHORT TERM (TODAY THROUGH FRIDAY)... LIGHT FREEZING PRECIPITATION CONTINUES OVER THE ADVY AND WARNING AREAS OF THE SRN EDWARDS PLATEAU...HILL COUNTRY AND BALCONES ESCARPMENT. A CLUSTER OF WEAK THUNDERSTORMS CROSSED FROM NRN MEXICO AND LOOKS TO BE PRODUCING A BRIGHT BAND OF WHAT IS PROBABLY SNOW MELTING INTO RAIN AND POSSIBLY A PARTIAL MELT/REFREEZE TO SLEET AND GRAUPEL. THIS CONVECTIVE AREA IS LOSING THE CELLULAR STRUCTURE AND SHOULD CONTINUE TO WEAKEN AS IT LIFTS NE. THUS WILL LEAVE OUT THE MENTION OF THUNDER AND LET NOWCASTS HANDLE WHAT SHOULD BE A SHORT-LIVED EVENT. THE DAYBREAK EMERGENCE OF CONVECTIVE SLEET BAND IS EXPECTED TO TRACK RIGHT ALONG THE EASTERN PART OF THE BALCONES ESCARPMENT. THUS AM HESITANT TO WARM MORNING TEMPERATURE FORECASTS TO MATCH THE CURRENT TRENDS HOLDING ABOVE FREEZING. HI-RES MODELS HAVE KEPT WITH THE CONVECTIVE BANDING AREA FORMING FARTHER NORTH...BUT THE LATEST RUNS OF THE HRRR DEPICT THE ONGOING CONVECTIVE AREA WELL AND SEND IT ACROSS THE AUSTIN METRO AREA AND NW PART OF THE SAN ANTONIO METRO AREA THROUGH DAYBREAK. WHILE THIS CLUSTER OF MODERATE PRECIPITATION COULD LOWER TEMPS TO FREEZING BRIEFLY...EXPECT THE WEAKENING TREND TO ALLOW MOST AREAS IN THE ADVISORY TO HOLD ONTO ABOVE FREEZING TEMPERATURES WITH MORE ISOLATED FROZEN CONDITIONS POSSIBLE AT HIGHER ELEVATIONS. A SECONDARY CONVECTIVE BAND REMAINS IN THE HRRR PICTURE WHICH SHOULD POTENTIALLY ADD TO THE FREEZING RAIN/SLEET MIX OVER THE WARNING AREA AT AROUND DAYBREAK. THUS THE ONGOING WINTER STORM WARNING AND WINTER WEATHER ADVISORY AREA IS THUS CONSIDERED APPROPRIATE AND NO WSW UPDATES ARE PLANNED. THE CONSENSUS MODEL POPULATION OF THE TEMPERATURES IN THE GRIDDED DATA SUGGESTED A QUICK WARM- UP TO ABOVE FREEZING...BUT WE FAVOR A MORE GRADUAL RISE IN THE MORNING PERIOD WHERE ICING HAS OCCURRED. BY NOON...MODEL SOUNDINGS SUGGEST THERE SHOULD BE AMPLE TIME FOR THE WARMING TO HAVE OCCURRED...AS THE FRONTAL INVERSION SHOULD CONTINUE TO BE MODIFIED BY FALLING RAIN AND DRIZZLE. A COLD RAIN REMAINS IN THE PICTURE THROUGH FRIDAY. TEMPERATURES SHOULD BE ALMOST FLAT FROM THIS AFTERNOON THROUGH LATE FRIDAY MORNING BEFORE WARMING INTO THE 40S OVER MOST AREAS LATE FRIDAY. DESPITE THE HIGH POPS BENEATH THE SOLID OVERRUNNING PATTERN...QPF AMOUNTS REMAIN CONSERVATIVE AND GENERALLY BELOW 1/2 INCH. LONG TERM (FRIDAY NIGHT THROUGH WEDNESDAY)... THE EASTWARD EJECTION OF A SLOW MOVING UPPER LOW BRINGS A SLIGHTLY MORE CONVECTIVE ENVIRONMENT TO TX BY FRIDAY EVENING. THE INCREASED POTENTIAL FOR THUNDER TRANSLATES TO SLIGHTLY HIGHER QPF AMOUNTS WITH ANOTHER 1/2 INCH OF RAIN POSSIBLE IN THE FRIDAY NIGHT PERIOD ALONE. MODEL CONSENSUS REMAINS IN GOOD AGREEMENT TO BRING DECREASING CLOUDS AND RAIN CHANCES BY MIDDAY SATURDAY AND PROBABLY THE WARMEST TEMPS OF THE WEEK. THIS IS BECAUSE ANOTHER FRONT ARRIVES BY SUNDAY MORNING. THE ECMWF TRENDED SHARPLY COLDER FROM THIS FRONT WITH A MUCH ENHANCED POLAR TROUGH OVER THE EASTERN US. THE GFS HAS ALSO TRENDED SLIGHTLY COLDER...SO A BLEND OF THESE TWO MODELS LOOKS REASONABLE. AM HESITANT TO BUY INTO THE ECMWF BASED GUIDANCE THAT PROJECTED MIDDLE TEENS OVER THE HILL COUNTRY MONDAY MORNING. THE COLD PATTERN IS SHOWN BY BOTH THE GFS AND ECMWF SOLUTIONS TO BE SHORT-LIVED WITH A PROGRESSIVE ZONAL PATTERN PUSHING AN UPPER RIDGE OVER TX BY MIDWEEK. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 39 38 43 40 59 / 80 90 80 80 30 AUSTIN BERGSTROM INTL AIRPORT 40 37 43 39 58 / 80 90 80 80 30 NEW BRAUNFELS MUNI AIRPORT 41 39 45 42 61 / 70 80 70 80 30 BURNET MUNI AIRPORT 38 35 40 37 57 / 90 90 80 80 20 DEL RIO INTL AIRPORT 41 41 49 41 61 / 40 50 40 50 - GEORGETOWN MUNI AIRPORT 40 36 41 38 56 / 90 90 80 80 30 HONDO MUNI AIRPORT 41 39 47 40 62 / 50 60 50 60 20 SAN MARCOS MUNI AIRPORT 40 38 44 41 59 / 70 80 70 80 30 LA GRANGE - FAYETTE REGIONAL 43 41 47 44 59 / 70 70 80 80 40 SAN ANTONIO INTL AIRPORT 41 39 46 42 61 / 60 80 60 70 20 STINSON MUNI AIRPORT 42 40 46 42 62 / 60 70 60 70 20 && .EWX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL NOON CST TODAY FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS...GILLESPIE... KENDALL...KERR...LLANO...REAL...VAL VERDE. && $$ MESOSCALE/AVIATION...04 SYNOPTIC/GRIDS...03 PUBLIC SERVICE/DATA COLLECTION...12