Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/01/13


AREA FORECAST DISCUSSION
NWS TUCSON AZ
830 PM MST SAT NOV 30 2013 .SYNOPSIS...MOSTLY CLOUDY CONDITIONS WILL CONTINUE INTO SUNDAY UNDER SOUTHWEST FLOW ALOFT. OTHERWISE MILD AND DRY CONDITIONS FOR THE REMAINDER OF THE WEEKEND INTO EARLY NEXT WEEK. AN AREA OF LOW PRESSURE NEAR JUNEAU ALASKA THIS EVENING WILL DIVE INTO THE PACIFIC NORTHWEST BY MONDAY AND THEN MOVE SLOWLY THROUGH THE WESTERN STATES FOR MUCH OF NEXT WEEK. THIS SYSTEM WILL BRING A CHANCE OF VALLEY RAIN AND MOUNTAIN SNOW TO SOUTHEAST ARIZONA LATE TUESDAY NIGHT THROUGH FRIDAY MORNING. THIS SYSTEM WILL ALSO BRING LOWER SNOW LEVELS...GUSTY WINDS AND MUCH COOLER TEMPERATURES. THE FIRST WIDESPREAD FREEZE FOR THE LOWER DESERTS IS POSSIBLE FRIDAY MORNING. && .DISCUSSION...THICK SHEAVES OF HIGH AND MID CLOUD CONTINUE TO STREAM UP FROM THE SOUTHWEST IN A RATHER LONG FETCH FROM THE TROPICS...STRETCHING ALL THE WAY FROM ABOUT 10-12 DEGREES NORTH LATITUDE RIGHT THROUGH SOUTHEAST ARIZONA. HRRR CONTINUING TO SHOW LIGHT PRECIP DEVELOPING THROUGH NORTHEAST SONORA AROUND 9 PM AND CLIPPING SOUTHEAST COCHISE COUNTY INCLUDING THE DOUGLAS AREA BETWEEN 10 PM AND MIDNIGHT. CONSIDERING SATELLITE TRENDS WITH MODEST PRECIPITABLE WATER INCREASE TO A LITTLE OVER 1/2 INCH A FEW SPRINKLES OR A LIGHT SHOWER NOT AT ALL OUT OF THE QUESTION FOR SOUTHEAST COCHISE COUNTY LATE THIS EVENING. CURRENT FORECAST TRENDS HITTING THE STRONG AND COLD SYSTEM IMPACTING THE AREA THE SECOND HALF OF NEXT WEEK LOOKS GOOD. INCREASING LEVELS OF PREDICTABILITY WITH ECMWF ENSEMBLE AND CONSENSUS TRENDS SUPPORT AN AGGRESSIVE APPROACH WITH AN UNUSUALLY STRONG AND COLD SYSTEM FOR EARLY DECEMBER. && .PREV DISCUSSION...THE FIRST DAY OF DECEMBER WILL BE MOSTLY CLOUDY WITH HIGHS CLOSE TO TODAY. ABOVE NORMAL TEMPERATURES WILL CONTINUE ON MONDAY AND TUESDAY BEFORE A SIGNIFICANT CHANGE IN THE WEATHER OCCURS...STARTING WEDNESDAY AND CONTINUING THROUGH NEXT WEEKEND. OUTSIDE OF A CHANCE OF PRECIPITATION ON LATE TUESDAY NIGHT THROUGH FRIDAY MORNING...THE MAIN WEATHER CONCERN WILL BE THE MUCH MUCH COLDER TEMPERATURES AS AN ARCTIC AIR MASS SETTLES IN OVER THE AREA. CONFIDENCE IS GROWING FOR A WIDESPREAD HARD FREEZE FRIDAY MORNING WHICH INCLUDES THE LOWER DESERTS. BELOW NORMAL TEMPERATURES CONTINUING THROUGH DECEMBER 9TH. MORNING PLOTS UP IN ALASKA PLACE A VERY COLD 514DM LOW NEAR YAKUTAT...WHICH IS THE PRIME SPOT FOR REALLY COLD TEMPERATURES ACROSS THE EASTERN INTERIOR OF ALASKA. THIS ARCTIC AIR MASS WILL WORK ITS WAY SOUTH SUNDAY AND MONDAY AS THE UPPER LOW MOVES TO NEAR SEATTLE MONDAY MORNING. ON TUESDAY...UPPER TROF DEEPENS TO OUR NW WITH PRESSURE GRADIENT STARTING TO TIGHTEN...THUS BRINGING SOME AFTERNOON BREEZES TO THE AREA. WILL SEE AN INCREASE IN MID-LEVEL MOISTURE LATE TUESDAY NIGHT THAT A FEW LIGHT VALLEY RAIN/MOUNTAIN SNOW SHOWERS COULD DEVELOP. WEDNESDAY...BREEZY TO LOCALLY WINDY AS UPPER TROF/ASSOCIATED COLD FRONT EDGES CLOSER TO THE AREA. PRECIPITATION CHANCES IN THE VALLEYS LESS THAN 30 PERCENT WITH 30%-50% IN THE MOUNTAINS. SNOW LEVEL WILL BE LOWERING TO 6000 FEET NORTH AND WEST TO 7500 FEET SOUTHEAST. HIGHS WILL BE 5-12 DEGREES COOLER THAN TUESDAY WITH THE LEAST AMOUNT OF CHANGE OCCURRING EAST OF TUCSON. WEDNESDAY NIGHT INTO THURSDAY...SNOW LEVEL CONTINUE TO SLOWLY FALL AS TROF AXIS PUSHES THROUGH THE STATE. STILL SOME TIMING ISSUES BETWEEN MODELS WHICH WILL BE RESOLVED OVER THE COMING DAYS. HIGHS ON THURSDAY 6-10 DEGREES COOLER THAN WEDNESDAY. THURSDAY NIGHT INTO FRIDAY...AS MENTIONED ABOVE THERE ARE TIMING DIFFERENCES BETWEEN THE MODELS WITH THE GFS BEING DRY WHILE ECMWF HOLDING ON TO A BIT MORE MOISTURE AND COMBINED WITH LOWER SNOW LEVELS...COULD SEE SOME FLAKES AT THE LOWEST ELEVATIONS EAST OF TUCSON. DEPENDING ON WHICH MODEL IS CORRECT IT WILL BE COLD AS THE MODIFIED ARCTIC AIR MASS SETTLES IN OVER THE AREA. LOWERED FORECAST LOWS FOR FRIDAY MORNING SIGNIFICANTLY FROM WHAT I INHERITED AND HAVE ALL OF SOUTHEAST ARIZONA BELOW FREEZING WITH THE FIRST WIDESPREAD HARD FREEZE FOR THE LOWER DESERTS POSSIBLE. SOME OF THE HIGHEST MOUNTAIN SPOTS WILL SEE LOWS IN THE SINGLE DIGITS. HIGHS ON FRIDAY WILL BE RATHER CHILLY...MAINLY IN THE 50S. SATURDAY...DRY AND WARMER. && .AVIATION...CONSIDERABLE CLOUDS ABOVE 15K FT WITH SCT-BKN 10K FT WILL CONTINUE ACROSS THE AREA THROUGH SUNDAY EVENING...OR 02/04Z. WINDS GENERALLY LESS THAN 10 KTS THROUGH 02/04Z WITH NORMAL DIURNAL TRENDS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...A NEARLY STATIONARY LOW WELL WEST OF THE BAJA CALIFORNIA COAST WILL PROVIDE DRY CONDITIONS AND CONSIDERABLE CLOUDS INTO EARLY NEXT WEEK. BY THE MIDDLE OF NEXT WEEK A STRONG TROUGH WILL DEVELOP ALONG THE WEST COAST. THIS TROUGH WILL CONTINUE TO DEEPEN INTO THE LATTER PART OF NEXT WEEK FOR A SIGNIFICANT CHANGE TOWARDS COLD TEMPERATURES AND INCREASED SHOWER ACTIVITY. A SLIGHT CHANCE OF SHOWERS STARTING LATE TUESDAY WITH INCREASING COVERING STARTING LATE WEDNESDAY INTO THURSDAY. DECREASING SHOWER COVERAGE ON FRIDAY AS SNOW LEVELS DROP TO AROUND 4000 FEET. ANTICIPATING THE STRONGEST SOUTHWEST WINDS OF 15-30 MPH TO OCCUR AHEAD OF THIS TROUGH AROUND MID WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON MEYER/GLUECK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
831 PM EST SAT NOV 30 2013 .UPDATE... BIG STORY TONIGHT WILL BE THE MOVEMENT AND DEVELOPMENT OF THE LOW CLOUDS AND FOG. ALREADY HAVE AN AREA OF LOW CLOUDS...CEILINGS BETWEEN 600 AND 1300 FEET MOVING SOUTHWEST FROM NORTHEAST FLORIDA INTO THE NATURE COAST. GLOBAL MODELS ARE HINTING AT SOME LOW CLOUDS AND FOG ACROSS MOST OF THE REGION BY SUNRISE...BUT THE LATEST HRRR IS GOING GLOOM AND DOOM AND BRINGING LOW CLOUDS... CEILINGS BELOW 500 FEET...ACROSS MOST OF THE REGION BY SUNRISE ALONG WITH WIDESPREAD FOG SOME OF WHICH IS DENSE WITH VISIBILITIES LESS THAN 1/2 MILE. IF THE HRRR IS RIGHT WE WILL END UP NEEDING A DENSE FOG ADVISORY FOR MUCH OF THE AREA LATE TONIGHT INTO EARLY SUNDAY MORNING. THEN DURING SUNDAY THE LOW CLOUDS AND FOG SHOULD LIFT AND DISSIPATE BY MIDDAY...BUT WE WILL STILL HAVE MOISTURE TRAPPED BELOW THE INVERSION LEADING TO MORE SCATTERED TO BROKEN STRATOCUMULUS/ALTOCUMULUS. HAVE ALREADY UPDATED THE GRIDS TO INCLUDE MORE CLOUDS AND FOG FOR TONIGHT INTO SUNDAY MORNING AND WILL UPDATE THE ZONES SHORTLY. OTHERWISE...REMAINDER OF FORECAST LOOKS OK AT THIS TIME. && .AVIATION... AREA OF LOW CLOUDS OVER NORTHEAST FLORIDA WILL EXPAND WEST AND SOUTH OVERNIGHT. HAVE FAIRLY HIGH CONFIDENCE IN MVFR/IFR CEILINGS BEGINNING AROUND 03Z OR SO MAINLY TPA...PIE AND LAL. WHILE LIFR CEILINGS ARE POSSIBLE FOR A BRIEF TIME TOWARD SUNRISE...CONFIDENCE TOO LOW TO INCLUDE IN TAFS AT THIS TIME. EXPECT LESS COVERAGE OF LOW CLOUDS AT SRQ...PGD...FMY AND RSW...BUT WILL CONTINUE TO MONITOR. PGD COULD SEE IFR/LIFR VISIBILITIES IN GROUND FOG BEFORE SUNRISE. && .MARINE... NORTHEAST WINDS WILL BEGIN TO DIMINISH LATE TONIGHT INTO SUNDAY AND THEN SHIFT TO NORTHERLY SUNDAY AFTERNOON. WINDS WILL CONTINUE TO BACK TO NORTHWEST TO WEST ON MONDAY AS THE HIGH PRESSURE TO THE NORTHEAST WEAKENS AND IS REPLACED BY DEVELOPING LOW PRESSURE OFF THE SOUTHEAST U.S. COAST. PRESENT MARINE FORECAST LOOKS OK WITH NO MAJOR CHANGES PLANNED FOR LATE EVENING FORECAST. && .PRELIMINARY POINT TEMPS/POPS... TPA 59 76 61 74 / 0 10 10 20 FMY 60 79 61 77 / 0 10 10 20 GIF 57 78 59 75 / 5 10 10 20 SRQ 59 77 60 74 / 0 10 10 20 BKV 53 76 54 74 / 0 10 10 20 SPG 62 75 63 73 / 0 10 10 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/MARINE...69/CLOSE AVIATION...63/JILLSON
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1135 PM CST THU NOV 28 2013 .UPDATE... ISSUED AT 917 PM CST THU NOV 28 2013 AN UPDATE WAS JUST SENT TO LOWER TEMPERATURES 2 OR 3 DEGREES OVER THE NORTHERN HALF OF THE FORECAST AREA. AT 03Z OBSERVED TEMPS WERE WITHIN A FEW DEGREES OF FORECAST MINS AT SEVERAL SITES NORTH OF I80. LIGHT AND VARIABLE WINDS AND CLEAR SKIES THE REST OF THE NIGHT WILL ALLOW TEMPS TO CONTINUE COOLING...REACHING THE SINGLE DIGITS TO AROUND 10 BY SUNRISE. && .SYNOPSIS... ISSUED AT 218 PM CST THU NOV 28 2013 A WEAK SURFACE LOW MOVED EASTWARD INTO SOUTHERN LAKE MICHIGAN DURING THE DAY ON THURSDAY WITH A COLD FRONT STRETCHING SOUTHWESTWARD TO KSTL TO KJLN IN SOUTHWEST MISSOURI. SURFACE HIGH SAT OVER EASTERN NORTH DAKOTA. STRATUS ALONG THE SOUTH AND WEST SIDES OF THE HIGH PRESSURE HAS SLOWLY DISSIPATED THROUGH THE DAY. TEMPERATURES WERE IN THE UPPER 20S IN NORTHWEST ILLINOIS TO THE LOWER 40S IN WEST CENTRAL ILLINOIS. A CHANGE IN THE 500 HPA PATTERN WILL OCCUR OVER THE NEXT SEVEN DAYS AS WE GO FROM THE CURRENT NORTHWEST FLOW ALOFT TO A MORE ZONAL FLOW WHICH WILL CONTINUE INTO EARLY NEXT WEEK. THIS WILL RESULT IN SLOWLY MODERATING TEMPERATURES AS THE COLD AIR OF THE LAST WEEK RETREATS NORTHWARD. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 218 PM CST THU NOV 28 2013 MODELS ARE IN GOOD OVERALL AGREEMENT WITH THE NAM/RAP BEING AN OUTLIER WITH LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION. THE MAIN FORECAST CONCERNS WILL BE THE POTENTIAL FOR CLOUD COVER OVERNIGHT INTO FRIDAY AS WELL AS TEMPERATURES ON FRIDAY. HIGH PRESSURE IS FORECAST TO BUILD SOUTHEASTWARD OVERNIGHT AND BE CENTERED ALONG THE IOWA AND ILLINOIS BORDER BY 12 UTC ON FRIDAY. AN EXTENSIVE STRATUS DECK DEVELOPED ON THE SOUTH AND WEST SIDES OF THE HIGH PRESSURE THIS MORNING WITH A STRONG INVERSION IN PLACE ACROSS THE UPPER MIDWEST AND NORTHERN PLAINS. THE 12 UTC SOUNDINGS AT KBIS AND KABR SHOWED EXTENSIVE LOW LEVEL MOISTURE IN PLACE. THE ECMWF...GFS... AND GEM CONTINUE TO SHOW A DRIER INVERSION IN PLACE ACROSS THE REGION OVERNIGHT WHILE THE NAM AND RAP SHOW MORE MOISTURE IN THE LOWER LEVELS OF THE ATMOSPHERE BUT NOT TO THE EXTENT THAT EXISTED AT KBIS AND KABR THIS MORNING. THEREFORE I AM NOT ANTICIPATING THE FORMATION OF NEW STRATUS TONIGHT SO GOING WITH CLEAR SKIES TONIGHT. A GOOD RADIATIONAL COOLING NIGHT AND EXPECT TEMPERATURES TO FALL QUICKLY THIS EVENING. HIGH PRESSURE IS FORECAST TO SHIFT EASTWARD DURING THE DAY ON FRIDAY WITH WINDS VEERING TO THE SOUTHEAST DURING THE AFTERNOON HOURS. 850 HPA TEMPERATURES WARM FROM -4 TO -10*C TODAY TO 0 TO -4*C ON FRIDAY. HAVE WARMED TEMPERATURES UP BY A COUPLE OF DEGREES BUT MID LEVEL CLOUDINESS WILL BE ON THE INCREASE TOMORROW AHEAD OF ANOTHER WAVE THAT WILL ARRIVE ON SATURDAY. THE INCREASING CLOUDS MAY HELP TO KEEP TEMPERATURES FROM WARMING AS THEY DID TODAY. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 218 PM CST THU NOV 28 2013 FRIDAY NIGHT...WEAK NORTHERN STREAM CLIPPER WILL CONTINUE MOVING TO GREAT LAKES BY SATURDAY MORNING. OVERNIGHT LOW TEMPERATURES WILL BE IN THE 20S. SATURDAY AND SUNDAY...TEMPERATURES WILL RANGE NEAR OR SLIGHTLY ABOVE NORMAL ON SATURDAY BEFORE A WEAK SURFACE TROF CROSSES THE AREA SWITCHING THE WIND TO THE WEST NORTHWEST LATE IN THE DAY. WITH LIMITED MOISTURE THIS TROF PASSAGE WILL BE DRY. ON SUNDAY...WEAK COLD AIR ADVECTION BEHIND THE TROF PASSAGE WILL PRODUCE LOW TEMPERATURES IN THE IN 20S ON SATURDAY NIGHT WITH HIGHS IN THE MID 30S ACROSS THE NORTHERN THIRD OF THE FORECAST AREA WITH HIGHS IN THE 40S OVER THE SOUTH. MONDAY THROUGH WEDNESDAY...LATEST MEDIUM RANGE MODEL SOLUTIONS CONTINUE TO DIVERGE BUT THERE IS OVERALL AGREEMENT IN DEVELOPING A DEEP TROF ACROSS THE WESTERN UNITED STATES BY MID WEEK. THE ENERGETIC SYSTEM CURRENTLY DIVING SOUTH ALONG THE WEST COAST WILL BEGIN A PERIOD OF ACTIVE WEATHER FOR THE MIDWEST. THE 12Z GFS KEEPS THE FORECAST AREA MAINLY DRY THROUGH TUESDAY. HOWEVER...THE 12Z ECMWF IS FASTER AND BRINGS PRECIPITATION INTO THE REGION ON MONDAY. IN EITHER CASE MOISTURE ADVECTION FROM THE GULF OF MEXICO AHEAD OF THE SURFACE LOW WILL BREAK OUT PRECIPITATION EITHER MONDAY OR TUESDAY. THE PRECIPITATION COULD FALL AS A MIXTURE OF RAIN AND SNOW. THURSDAY AND FRIDAY...CONFIDENCE IS LOW AS MODEL SOLUTIONS SHOW MAJOR DISCREPANCIES. THE 12Z RUN OF THE ECMWF PROGS A SURFACE LOW TO DEVELOP OVER THE CENTRAL ROCKIES AND TRACK NORTHWEST OF IOWA ON THURSDAY. IF THIS TRACK IS CORRECT WARM AIR ADVECTION AHEAD OF THIS LOW WOULD PRODUCE A RAIN OR RAIN/SNOW MIX TURNING TO ALL RAIN WITH A SNOW STORM OCCURRING OVER WESTERN IOWA AND THE NORTHERN PLAINS. ON THE OTHER HAND THE 12Z RUN OF THE GFS TRACKS THE SURFACE LOW FURTHER SOUTHEAST AND PROGS IT TO MOVE ACROSS MISSOURI INTO NORTHERN ILLINOIS/INDIANA BY FRIDAY. IF THE GFS SOLUTION IS CORRECT THERMAL PROFILES WOULD SUPPORT AN ALL SNOW EVENT LATE NEXT WEEK. HOWEVER I MUST STRONGLY REITERATE FORECAST CONFIDENCE IS LOW.&& && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 1128 PM CST THU NOV 28 2013 VFR CONDITIONS WILL PREVAIL THROUGH FRIDAY EVENING. CLEAR SKIES AND LIGHT WINDS WILL REMAIN OVER THE AREA TONIGHT AS HIGH PRESSURE DRIFTS EAST THROUGH THE REGION. FRIDAY...WITH THE HIGH TO THE EAST...WINDS WILL PICKUP OUT OF THE SOUTHEAST WITH HIGH CLOUDS OVER SPREADING THE AREA DURING THE AFTERNOON AND EVENING. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ UPDATE...DLF SYNOPSIS...COUSINS SHORT TERM...COUSINS LONG TERM...KUHL AVIATION...DLF
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
941 PM EST SAT NOV 30 2013 .SYNOPSIS... A WEAK FRONTAL SYSTEM WILL INCREASE CLOUDS ON SUNDAY WITH A SLIGHT CHANCE OF PRECIPITATION LATE IN THE DAY AND INTO MONDAY. ANOTHER FRONT WILL GIVE US A SMALL CHANCE OF A SHOWER OR SPRINKLE ON WEDNESDAY. THE BEST CHANCE OF RAIN THIS WEEK WILL COME LATE ON THURSDAY INTO EARLY FRIDAY ALONG WITH MILDER TEMPERATURES. && .NEAR TERM /THROUGH SUNDAY/... 940 PM UPDATE... TEMPERATURES WERE PLUMMETING EARLIER THIS EVENING WITH LIGHT WINDS AND COMPLETELY CLEAR SKIES. HOWEVER...SWATH OF CI/HIGH AC HALTED QUICK DROP AND ACTUALLY SOME PLACES (KBTP) WENT UP A COUPLE OF DEGREES. HRRR STILL ADVERTISING A LITTLE SLOWER CLOUD ADVECTION AND WINDS IN SEVERAL SPOTS STILL LIKELY TO DECOUPLE. WITH YET ANOTHER CLEAR AREA LIKELY TO TRANSLATE THE REGION...HAVE COMPROMISED ON MINS. DROPPING THEM FROM ORIGINAL LEVELS (ESPECIALLY OVER SNOW COVER) BUT ALSO TEMPERING WITH THE CLOUD COVER WHICH WILL LIKELY MOVE IN TOWARD MORNING. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... ONE THING SUMMARIZES THIS PERIOD...CLOUDY. SOUNDINGS AND TIME HEIGHTS SHOW RH NEAR 100% IN THE LOWEST 8KFT. LITTLE CHANGE NEEDED TO GRIDDED DATA SET AS CONTINUITY EXISTS FROM NCEP SUITE. DID BRING SCHC POPS FARTHER S SUN NGT AS S/W TROUGH IS PROGGED TO CROSS PA OPPOSE TO STAYING N ALONG THE LAKE. THIS COULD YIELD AN ISOLD RW/SW. CLOUD TOP TEMPS HAVE INCREASED SO POSSIBILITY OF RA OR SN EXISTS RATHER THAN DZ / FZDZ. NOT A LOT OF FORCING PRESENT SO QPF AMOUNTS WILL BE ON THE ORDER A FEW HUNDREDTHS. BEST SHOT FOR MEASURABLE PCPN ARRIVES MON NGT INTO TUE WHEN NEGATIVELY TILTED TROF AXIS PASSES. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... HIGHLIGHTS: - TEMPS AROUND 5-10F ABOVE NORMAL WED - FRI - SOGGY WEATHER THUR - FRI - LOTS OF UNCERTAINTY FRI NGT - SAT LONG RANGE NUMERICAL WEATHER SUITE STILL HAS A LOT OF SPREAD IN DETAILS IN THE FIRST PART THEN CONVERGE NICELY FOR THE MAIN SYNOPTIC SYSTEM. CONSISTENCY DOES NOT LAST LONG AS THEY DIVERGE AT THE END. GREATEST CERTAINTY IN THE FORECAST RESIDES THUR NGT INTO FRI WITH INCREASED UNCERTAINTY AT THE BOOKENDS /WED AND NEXT SAT/. ECMWF CONTINUES WITH GOOD RUN TO RUN CONSISTENCY VIA DPROG/DT VERSUS GFS. ECMWF MAINTAINS A STRONG ERN CONUS RIDGE DUE TO STRONGER CYCLONE ACROSS SRN CANADA. THIS CORRELATES WELL GIVEN ANOMALOUS DEVIATIONS IN H5 HGTS AND H8 TEMPS ILLUSTRATED BY GEFS. MUCH LIKE YESTERDAY/S FORECAST...IT WAS CONSTRUCTED FROM ECMWF. PATTERN/S AMPLITUDE DOES NOT OWE ITSELF TO GFS HEIGHT FIELD RELATIVELY FLAT AND TRANSITORY AND AS WPC DISCUSSED IT WAS DISCARDED. FOR WED...KEPT THINGS DRY LIKE ONGOING FORECAST WITH BAROCLINIC ZONE ACROSS IND /DESPITE GFS SHOWING FROPA IN WRN PA/. WARM FRONT CROSSES DURING THE MORNING ALLOWING SUNSHINE AND WARMER WEATHER COME AFTN. DEPENDING HOW FAR N BOUNDARY GETS COULD SEE A 15F SPREAD FOR MAXT...FROM L40S DUJ-FKL TO M50S IN FAIRMONT. COLD FRONT APPROACHES WED NGT SO POPS INC FM W TO E DURING THE OVERNIGHT HRS. LATTER PART OF THE WORK WEEK GFS HAS COME AROUND TO ECMWF THINKING WITH A SFC LOW RIDING NE ALONG DISSIPATED COLD FRONT THAT CROSSED WED NGT. PLENTY OF MOISTURE SURGES INTO THE OHIO VALLEY CREATING PWATS VALUES AROUND AN INCH...WHICH IS TWO STANDARD DEVIATIONS ABOVE NORMAL. POPS WERE INCREASED TO LKLY THUR - FRI WHICH CORRESPONDS WITH STATISTICAL GUIDANCE. RAINFALL AMOUNTS STILL LOOK TO BE HIGHEST ALONG AND JUST WEST OF THE MOUNTAINS WHERE CLOSE TO AN INCH COULD FALL. ECNTRL OH E INTO FAR WRN PA SHOULD SEE LESS...ROUGHLY 1/2 TO 3/4 OF AN INCH. FRI NGT INTO SAT MODELS DIVERGE ONCE AGAIN WITH GFS BLOWING FRONT THROUGH AND BUILDING IN HIGH PRESSURE GIVEN LESS AMPLIFIED PATTERN. ECMWF IS SLOWER WITH EXODUS OF FRONT. THERE IS A POTENTIAL FOR A SHORT PERIOD OF SNOW BEFORE BOUNDARY VACATES SAT MRNG PER ECMWF GIVEN LLVL THERMAL PROFILES...BUT NOTHING SIGNIFICANT. ANY SNOW ON THE BACKSIDE FROM GFS WILL BE WITH UPSLOPE / LAKE ENHANCED AS COLD AIR INVADES FROM THE W. GREAT LAKES WILL MODIFY AIRMASS SO ARCTIC OUTBREAK THAT IS BEING ADVERTISED IN THE PLAINS THIS WEEK...WON`T BE AS BAD THE TIME IT GETS HERE. NONETHELESS...STILL EXPECT TEMPS TO BE BELOW NORMAL NEXT WEEKEND. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... SKIES CLEARING WITH WEAK FRONT APPROACHING REGION ON SUNDAY. INCREASED CLOUDS TOWARD MORNING BUT STILL VFR. MOISTURE AT A PREMIUM WITH FRONT AND ONLY SLIGHT CHANCE PRECIPITATION. DID NOT INCLUDE IN TAFS. WINDS LIGHT OVERNIGHT WITH SE 5 TO 10 ACROSS NORTH BECOMING SOUTHERLY AND SW ON SUNDAY. .OUTLOOK.../00Z MONDAY THROUGH THURSDAY/... TUESDAY SOME REMNANT CLOUDS AND POSSIBLE SPRINKLE OR FLURRIES ACROSS NORTH. WEAK HIGH PRESSURE FOR WEDNESDAY. ANOTHER WEAK FRONT APPROACHES FOR THURSDAY WITH POSSIBLE SCATTERED MVFR. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
339 PM EST FRI NOV 29 2013 .SYNOPSIS... A GRADUAL WARMING TREND THE COMING DAYS BACK TO NORMAL LEVELS. THE NEXT FRONT CROSSES SUNDAY...WITH ANY RAIN OR SNOW CONFINE TO AREAS ALONG AND NORTH OF INTERSTATE 80. LOTS OF CLOUDS ARE FORECASTED FOR EARLY NEXT WEEK. && .NEAR TERM /THROUGH SATURDAY/... AFTER A BRIEF CLEARING...MID LEVEL CLOUD COVERAGE WILL INCREASE THROUGH THE AFTERNOON AS FLOW ALOFT TURNS NORTHWEST BEHIND THE SHORTWAVE THAT PASSED OVER THIS MORNING. HAVE ADJUSTED TEMPERATURES SLIGHTLY UPWARDS BASED ON LATEST OBS TRENDS...HOWEVER...DAYTIME MAX HIGHS ARE STILL EXPECTED TO BE APPROXIMATELY 10 DEGREES BELOW CLIMO NORMS TODAY. TONIGHT WINDS WILL TURN SOUTHWESTERLY...AND THE INCREASED WAA WILL INITIATE A WARMING TREND IN TEMPERATURES THROUGH THE REMAINDER OF THE WEEKEND. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... HIGH PRESSURE CONTINUES TO RETREAT INTO NEW ENGLAND SAT NGT...HOWEVER RETURN FLOW ALLOWS FOR A WARMER NIGHT WITH SWRLY WINDS OUT AHEAD. OVERALL MODELS ARE IN GOOD AGREEMENT WITH THE NEXT WEATHER SYSTEM SUN - MON NIGHT. BOTH DEPICT A FULL LATITUDE TROUGH ACROSS THE EASTERN CONUS...BUT LITTLE IN THE WAY OF ANY BAROCLINICTY AT THE SFC. ALL OF THE ENERGY RESIDES WITH THE CYCLONE TRACKING OFF THE ERN SEABOARD. UPSTAIRS THERE ARE PASSING S/W TROUGHS DURING THIS PERIOD THAT WILL YIELD LIGHT QPF. H5 TROUGH BECOMES NEGATIVELY TILED AS IT SWEEPS THROUGH MONDAY NIGHT...BUT WITH THE LACK OF AGEOSTROPHIC DIVERGENCE AT H2 AND 5-10KTS OF LLVL CONV...ONLY LIGHT PCPN EXPECTED. CONTINUED THEME OF HIGHLIGHTING AREAS ALONG AND N OF I-80 FOR MEASURABLE QPF SUNDAY INTO SUNDAY NIGHT. THERMAL PROFILES ILLUSTRATE POTENTIAL FOR A RA/SN MIX. HIGH PROBABILITY OF ALL SNOW THE CLOSER TO LAKE ERIE AS COLUMN IS COLDER. && .LONG TERM /TUESDAY THROUGH FRIDAY/... HIGHLIGHTS: - SLOW WARMING TREND CONTINUES - ABOVE NORMAL TEMPS BY THE END OF NEXT WEEK - STRONG LOW PRESSURE PASSES THUR - FRI FORECAST CONFIDENCE IS ABOVE AVERAGE FOR THE FIRST TWO DAYS OF THE LONG RANGE THEN LOWERS. TRANSITORY MID LVL RIDGE CROSSES MID WEEK ALLOWING TEMPS TO WARM INTO THE 40S MELTING ANY LEFTOVER SNOW PACK. LATTER PART OF THE WEEK BOTH OPERATIONAL RUNS OF ECMWF AND GFS SHOW A GOOD SHOT AT RAIN WITH LOW PRESSURE TRAVELING ALONG THE MTNS. THIS TRACK WHICH IS FURTHER SUPPORTED BY THEIR RESPECTIVE ENSEMBLE MEANS PLACE US ON THE WARM SIDE OF THE SYSTEM. THE CHALLENGE IS TIMING AND IF A SECOND WAVE RIDES ALONG THE BOUNDARY AS MID LVL FLOW BECOMES PARALLEL TO THE FRONT. STRONG ISENTROPIC UPGLIDE ON 290-300K WITH WINDS INTERESTING THETA SFCS AT RIGHT ANGLES. SPECIFIC HUMIDITY VALUES PUSH 4-5 GKG-1 WHICH IS ABOVE NORMAL THIS TIME OF YEAR. GEFS PLUME DIAGRAMS SHOW POTENTIAL FOR 0.50 TO 1.25 INCHES OF RAIN WITH VERY LITTLE SNOW ON THE BACK SIDE. THIS IS NOTHING THAT WOULD LEAD TO HIGH WATER DUE TO ALL THE SNOW HAS MELTED AND WE WILL BE DRY THE DAYS LEADING UP. A LOT OF SPREAD EXISTS AFTER THE COLD FRONT COMES THROUGH. ECMWF IS STRONGER WITH UPSTREAM RIDGE AXIS THEREBY HAVING ANOTHER WAVE OF LOW PRESSURE PASSING FRIDAY W OF THE MTNS. GFS IS WEAKER WITH RIDGE THUS HAVING LOW PRESSURE PASS TO OUR SE. GIVEN GUIDANCE SPREAD FROM MOS IS WELL INTO THE 60S ROLLED WITH LKLY POPS NEXT THUR AND FRI. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... STRATOCU ARE EXPD TO CONT TO PLAGUE UPR OH VALLEY PORTS TDA AS A WEAK FRONT SAGS ACRS THE REGION IN THE WAKE OF AN EXITING UPR DISTURBANCE. GIVEN LOW CONVECTIVE THRESHOLDS UNDR A LOWERING INVERSION...HAVE ELECTED TO FOLLOW A MORE PESSIMISTIC HRRR PROGNOSIS OF MVFR CIGS FOR MUCH OF THE DAY FOR PORTS N OF I 70. BLDG HIGH PRES WL SPPRT VFR LTR IN THE DAY AND FOR THE RMNDR OF THE TAF PD. .OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/... NO WIDESPREAD AREAS OF IFR WEATHER EXPECTED. BRIEF MVFR RESTRICTIONS ARE POSSIBLE WITH THE NEXT WEATHER SYSTEM SUNDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ SYNOPSIS...98 NEAR TERM...88 SHORT TERM...98 LONG TERM...98 AVIATION...88/98
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1226 PM EST FRI NOV 29 2013 .SYNOPSIS... ANOTHER COLD DAY...BUT TEMPERATURES WILL BEGIN TO MODERATE SATURDAY. THE NEXT COLD FRONT CROSSES ON SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AFTER A BRIEF CLEARING...MID LEVEL CLOUD COVERAGE WILL INCREASE THROUGH THE AFTERNOON AS FLOW ALOFT TURNS NORTHWEST BEHIND THE SHORTWAVE THAT PASSED OVER THIS MORNING. HAVE ADJUSTED TEMPERATURES SLIGHTLY UPWARDS BASED ON LATEST OBS TRENDS...HOWEVER...DAYTIME MAX HIGHS ARE STILL EXPECTED TO BE APPROXIMATELY 10 DEGREES BELOW CLIMO NORMS TODAY. TONIGHT WINDS WILL TURN SOUTHWESTERLY...AND THE INCREASED WAA WILL INITIATE A WARMING TREND IN TEMPERATURES THROUGH THE REMAINDER OF THE WEEKEND. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... CLOUD COVERAGE WILL GRADUALLY INCREASE IN THE UPPER LEVELS SATURDAY IN ADVANCE OF A WEAK SHORTWAVE TO BRUSH THE AREA ON SUNDAY. WEAK COLD FRONT ATTEMPTS TO CROSS THE AREA LATE SUNDAY. FRONT HAS ALMOST NO UPPER LEVEL SUPPORT AND MOISTURE WILL REMAIN TO THE NORTH OF THE BOUNDARY. HAVE KEPT POPS ACROSS THE NORTH SUNDAY IN THE AREA OF DEEPEST MOISTURE. TEMPS ON SUNDAY VERY CLOSE TO SATURDAY`S EXPECTED READINGS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... WILL CONTINUE WITH A DRY LONG TERM...ALTHOUGH UNCERTAINTIES ARISE TUESDAY IN RELATION TO THE AFFECT FROM THE PASSAGE OF A WEAK WARM FRONT. TEMPS BELOW NORMAL TO BEGIN THE WORK WEEK...WITH SOME MODERATION BY THE END OF THE PERIOD. && .AVIATION /17Z FRIDAY THROUGH TUESDAY/... STRATOCU ARE EXPD TO CONT TO PLAGUE UPR OH VALLEY PORTS TDA AS A WEAK FRONT SAGS ACRS THE REGION IN THE WAKE OF AN EXITING UPR DISTURBANCE. GIVEN LOW CONVECTIVE THRESHOLDS UNDR A LOWERING INVERSION...HAVE ELECTED TO FOLLOW A MORE PESSIMISTIC HRRR PROGNOSIS OF MVFR CIGS FOR MUCH OF THE DAY FOR PORTS N OF I 70. BLDG HIGH PRES WL SPPRT VFR LTR IN THE DAY AND FOR THE RMNDR OF THE TAF PD. .OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/... THE NXT CHC FOR RESTRICTIONS WL COME WITH A SUNDAY CDFNT...ALTHOUGH PCPN MAY BE SPARSE. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
915 AM EST FRI NOV 29 2013 .SYNOPSIS... ANOTHER COLD DAY...BUT TEMPERATURES WILL BEGIN TO MODERATE SATURDAY. THE NEXT COLD FRONT CROSSES ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ONLY CHANGES NEEDED FOR THE MID MORNING UPDATE WERE TWEAKS TO HOURLY TRENDS OF CLDS AND TEMPS. PREVIOUS... COLD AIR REMAINS OVER THE AREA TODAY. LATEST MODEL SOUNDINGS AND HIRES SOLUTIONS ARE SHOWING CLOUDS DECREASING THIS MORNING FROM SOUTHWEST TO NORTHEAST...AS ATMOSPHERE TEMPORALLY DRIES OUT. HOWEVER ANOTHER PUSH OF COLDER AIR THIS AFTERNOON WILL PROMOTE CLOUD REDEVELOPMENT. TEMPS AGAIN...WELL BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... WAA WILL BE ON THE INCREASE TONIGHT AND SATURDAY WHICH WILL RESULT IN A WARMING TREND IN TEMPERATURES SATURDAY. CLOUD COVERAGE WILL GRADUALLY INCREASE IN THE UPPER LEVELS SATURDAY IN ADVANCE OF A WEAK SHORTWAVE TO BRUSH THE AREA ON SUNDAY. WEAK COLD FRONT ATTEMPTS TO CROSS THE AREA LATE SUNDAY. FRONT HAS ALMOST NO UPPER LEVEL SUPPORT AND MOISTURE WILL REMAIN TO THE NORTH OF THE BOUNDARY. HAVE KEPT POPS ACROSS THE NORTH SUNDAY IN THE AREA OF DEEPEST MOISTURE. TEMPS ON SUNDAY VERY CLOSE TO SATURDAY`S EXPECTED READINGS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... WILL CONTINUE WITH A DRY LONG TERM...ALTHOUGH UNCERTAINTIES ARISE TUESDAY IN RELATION TO THE AFFECT FROM THE PASSAGE OF A WEAK WARM FRONT. TEMPS BELOW NORMAL TO BEGIN THE WORK WEEK...WITH SOME MODERATION BY THE END OF THE PERIOD. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... STRATOCU ARE EXPD TO CONT TO PLAGUE UPR OH VALLEY PORTS TDA AS A WEAK FRONT SAGS ACRS THE REGION IN THE WAKE OF AN EXITING UPR DISTURBANCE. GIVEN LOW CONVECTIVE THRESHOLDS UNDR A LOWERING INVERSION...HAVE ELECTED TO FOLLOW A MORE PESSIMISTIC HRRR PROGNOSIS OF MVFR CIGS FOR MUCH OF THE DAY FOR PORTS N OF I 70. BLDG HIGH PRES WL SPPRT VFR LTR IN THE DAY AND FOR THE RMNDR OF THE TAF PD. .OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/... THE NXT CHC FOR RESTRICTIONS WL COME WITH A SUNDAY CDFNT...ALTHOUGH PCPN MAY BE SPARSE. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
632 AM EST FRI NOV 29 2013 .SYNOPSIS... ANOTHER COLD DAY...BUT TEMPERATURES WILL BEGIN TO MODERATE SATURDAY. THE NEXT COLD FRONT CROSSES ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ONLY CHANGES NEEDED FOR THE NR DAWN UPDATE WERE TWEAKS TO HOURLY TRENDS OF CLDS AND TEMPS. PREVIOUS... COLD AIR REMAINS OVER THE AREA TODAY. LATEST MODEL SOUNDINGS AND HIRES SOLUTIONS ARE SHOWING CLOUDS DECREASING THIS MORNING FROM SOUTHWEST TO NORTHEAST...AS ATMOSPHERE TEMPORALLY DRIES OUT. HOWEVER ANOTHER PUSH OF COLDER AIR THIS AFTERNOON WILL PROMOTE CLOUD REDEVELOPMENT. TEMPS AGAIN...WELL BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... WAA WILL BE ON THE INCREASE TONIGHT AND SATURDAY WHICH WILL RESULT IN A WARMING TREND IN TEMPERATURES SATURDAY. CLOUD COVERAGE WILL GRADUALLY INCREASE IN THE UPPER LEVELS SATURDAY IN ADVANCE OF A WEAK SHORTWAVE TO BRUSH THE AREA ON SUNDAY. WEAK COLD FRONT ATTEMPTS TO CROSS THE AREA LATE SUNDAY. FRONT HAS ALMOST NO UPPER LEVEL SUPPORT AND MOISTURE WILL REMAIN TO THE NORTH OF THE BOUNDARY. HAVE KEPT POPS ACROSS THE NORTH SUNDAY IN THE AREA OF DEEPEST MOISTURE. TEMPS ON SUNDAY VERY CLOSE TO SATURDAY`S EXPECTED READINGS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... WILL CONTINUE WITH A DRY LONG TERM...ALTHOUGH UNCERTAINTIES ARISE TUESDAY IN RELATION TO THE AFFECT FROM THE PASSAGE OF A WEAK WARM FRONT. TEMPS BELOW NORMAL TO BEGIN THE WORK WEEK...WITH SOME MODERATION BY THE END OF THE PERIOD. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... STRATOCU ARE EXPD TO CONT TO PLAGUE UPR OH VALLEY PORTS TDA AS A WEAK FRONT SAGS ACRS THE REGION IN THE WAKE OF AN EXITING UPR DISTURBANCE. GIVEN LOW CONVECTIVE THRESHOLDS UNDR A LOWERING INVERSION...HAVE ELECTED TO FOLLOW A MORE PESSIMISTIC HRRR PROGNOSIS OF MVFR CIGS FOR MUCH OF THE DAY FOR PORTS N OF I 70. BLDG HIGH PRES WL SPPRT VFR LTR IN THE DAY AND FOR THE RMNDR OF THE TAF PD. .OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/... THE NXT CHC FOR RESTRICTIONS WL COME WITH A SUNDAY CDFNT...ALTHOUGH PCPN MAY BE SPARSE. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$ 15/22
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
401 AM EST FRI NOV 29 2013 .SYNOPSIS... ANOTHER COLD DAY...BUT TEMPERATURES WILL BEGIN TO MODERATE SATURDAY. THE NEXT COLD FRONT CROSSES ON SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... COLD AIR REMAINS OVER THE AREA TODAY. LATEST MODEL SOUNDINGS AND HIRES SOLUTIONS ARE SHOWING CLOUDS DECREASING THIS MORNING FROM SOUTHWEST TO NORTHEAST...AS ATMOSPHERE TEMPORALLY DRIES OUT. HOWEVER ANOTHER PUSH OF COLDER AIR THIS AFTERNOON WILL PROMOTE CLOUD REDEVELOPMENT. TEMPS AGAIN...WELL BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/... WAA WILL BE ON THE INCREASE TONIGHT AND SATURDAY WHICH WILL RESULT IN A WARMING TREND IN TEMPERATURES SATURDAY. CLOUD COVERAGE WILL GRADUALLY INCREASE IN THE UPPER LEVELS SATURDAY IN ADVANCE OF A WEAK SHORTWAVE TO BRUSH THE AREA ON SUNDAY. WEAK COLD FRONT ATTEMPTS TO CROSS THE AREA LATE SUNDAY. FRONT HAS ALMOST NO UPPER LEVEL SUPPORT AND MOISTURE WILL REMAIN TO THE NORTH OF THE BOUNDARY. HAVE KEPT POPS ACROSS THE NORTH SUNDAY IN THE AREA OF DEEPEST MOISTURE. TEMPS ON SUNDAY VERY CLOSE TO SATURDAY`S EXPECTED READINGS. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... WILL CONTINUE WITH A DRY LONG TERM...ALTHOUGH UNCERTAINTIES ARISE TUESDAY IN RELATION TO THE AFFECT FROM THE PASSAGE OF A WEAK WARM FRONT. TEMPS BELOW NORMAL TO BEGIN THE WORK WEEK...WITH SOME MODERATION BY THE END OF THE PERIOD. && .AVIATION /09Z FRIDAY THROUGH TUESDAY/... STRATOCU ARE EXPD TO CONT TO PLAGUE UPR OH VALLEY PORTS TDA AS A WEAK FRONT SAGS ACRS THE REGION IN THE WAKE OF AN EXITING UPR DISTURBANCE. GIVEN LOW CONVECTIVE THRESHOLDS UNDR A LOWERING INVERSION...HAVE ELECTED TO FOLLOW A MORE PESSIMISTIC HRRR PROGNOSIS OF MVFR CIGS FOR MUCH OF THE DAY. BLDG HIGH PRES WL SPPRT LTR IN THE DAY AND FOR THE RMNDR OF THE TAF PD. .OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/... THE NXT CHC FOR RESTRICTIONS WL COME WITH A SUNDAY CDFNT...ALTHOUGH PCPN MAY BE SPARSE. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
916 PM EST SAT NOV 30 2013 .UPDATE... CURRENT CONDITIONS ARE CERTAINLY SUPPORTIVE OF FOLLOWING THE PREVIOUS FORECASTS THOUGHTS ON LOWER CHANCES OF PRECIPITATION THAN WHAT THE 12Z AND 18Z MODELS ARE SUGGESTING. NEARLY ALL OF THE RADAR RETURNS OVER LOWER MICHIGAN ARE VIRGA. LATEST RUC RUNS ARE MORE SUPPORTIVE OF A DRIER OVERNIGHT AND ARE REALLY IN LINE WITH THE CURRENT FORECAST POPS...CLOUDS AND QPF. 00Z SOUNDINGS AND THE LATEST RUC SOUNDINGS SUGGEST THAT IT WILL TAKE SOME TIME TO SATURATE THE LAYER BETWEEN 3K AND 6K FEET. WHILE THERE IS SOME MOISTURE ALONG THE FRONT BELOW 3K FEET...IT IS REALLY ABOVE THIS THAT DRY AIR REMAINS IN PLACE TO LIMIT PRECIP. THE OTHER ITEM THAT SHOWS WELL IN THE SOUNDINGS IS THAT THE FREEZING LEVEL WILL LIKELY BE 1000 TO 2000 FEET ABOVE THE SURFACE WHEN WE FIRST SATURATE. ANY PRECIP THAT HAS FALLEN ACROSS NRN LOWER THIS EVENING HAS BEEN RAIN. THEREFORE WILL BRING IN A MIX OF RAIN...AT LEAST AT THE START...FOR ANY PLACE THE DOES GET SOME PRECIP OVERNIGHT. WILL RAISE TEMPS JUST A BIT OVERNIGHT DUE TO THE COMBINATION OF THE CLOUDS AND SOUTHERLY WIND AHEAD OF THE COLD FRONT. TEMPS WILL EVENTUALLY REACH THEIR FORECAST LOWS WITH THE FRONTAL PASSAGE OR WITH THE EVAPORATE COOLING. THE EXCEPTION WILL BE IN THE FAR SOUTH OF THE FORECAST AREA WHERE MOSTLY CLEAR SKIES ARE ALLOWING TEMPS TO FALL. && .AVIATION...ISSUED 623 PM EST SAT NOV 30 2013 //DISCUSSION... WILL CONTINUE THE TREND OF A SLOWER PROGRESSION OF THE LOW LEVEL MOISTURE THAT THE MODELS DEPICT. HOWEVER WITH THE LATEST MODEL RUNS AND THE EVIDENCE OF SOME LOWER MVFR CIGS ACROSS THE U.P. AND NORTHERN LOWER...DID MOVE THE LOWER CIGS UP IN TIME FOR THE TAF SITES. LIMITED PRECIPITATION MENTION TO KMBS...09-13Z...WHERE DEEPER MIDLEVEL MOISTURE CLIPS THE SAGINAW VALLEY/THUMB. WHILE THEIR MAY BE A BRIEF PERIOD OF RAIN AT THE START LIKE AT PLN THIS EVENING...DRY AND COLD AIRMASS SHOULD ALLOW WET BULBING TO SUPPORT SNOWFLAKES AS THE DOMINANT HYDROMETEOR TYPE. KEPT VISIBILITY OBSTRUCTIONS FROM -SN IN THE MVFR RANGE. HIGH CONFIDENCE IN MVFR CLOUDS AFTER PASSAGE OF THE SURFACE FRONT...WHEN CLOUDS WILL THEN PERSIST FOR A LONG DURATION. FOR DTW...DRY AIRMASS PRE COLD FRONT TONIGHT WILL KEEP CLOUDS ABOVE 5000 FT. MODELS APPEAR OVERDONE ON LOW LEVEL SATURATION LATE TONIGHT/EARLY TOMORROW MORNING. MVFR CLOUD WILL THEN SETTLE OVER THE TAF SITE DURING SUNDAY MORNING IN RESPONSE TO LOW LEVEL COLD AIR ADVECTION. //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FT PRIOR TO 12Z SUNDAY. HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET BEGINNING SUNDAY MORNING. && .PREV DISCUSSION...ISSUED 319 PM EST SAT NOV 30 2013 SHORT TERM...TONIGHT A THERMAL WAVE DIGGING SOUTHEASTWARD ALONG THE TRAILING EDGE OF NE NORTH AMERICAN UPPER LEVEL TROUGH WILL BE THE WEATHER AFFECTING THE CENTRAL GREAT LAKES TONIGHT. THE CYCLONIC VORTICITY ENERGY ASSOCIATED WITH THE SHORT WAVELENGTH THERMAL RIDGE IS FRAGMENTED WITH THE INITIAL SHORTWAVE DAMPENING WHILE IT PUSHES EAST OF LAKE SUPERIOR THIS AFTERNOON. A SECOND SHORTWAVE IS NOW SLIDING THROUGH THE MINNESOTA ARROWHEAD AND INTO THE FAR WESTERN LAKE SUPERIOR BASIN TAKING OVER WITH TIME. THIS SHORTWAVE WILL PROVIDE A NECESSARY FORCING COMPONENT AFTER 9Z OVER THE FAR NORTHERN CWA WHICH SHOULD FINALLY ALLOW PRECIPITATION TO FALL. OTHERWISE THE MIX OF DYNAMICS SUPPORTIVE OF ASCENT IS LIMITED. ANALYSIS OF 285K SYSTEM RELATIVE ISENTROPIC ASCENT IS VERY UNINSPIRING DESPITE SOME LINKAGE OF RIGHT ENTRANCE REGION DYNAMICS ALOFT WITH 850-700MB DEFORMATION. THE DEFORMATION IS MODELED TO BE ASSOCIATED WITH THE CONVERGENCE FEATURE OF THE FRONT. EXPECT THIS FORCING TO STRIPE FOR A VERY LIMITED TIME FROM WEST TO EAST NORTHEAST...PRIMARILY ACROSS THE FAR NORTHERN COUNTIES. WET BULB AND OFFERED BUFKIT SOUNDINGS SUPPORT AN ALL SNOW EVENT...TRENDED TO ALL SNOWFLAKES. A DUSTING WILL BE POSSIBLE NORTH AFTER 8Z...PERHAPS A HALF TO 1 INCH IN THE NORTHERN THUMB. LONG TERM...SUNDAY THROUGH NEXT SATURDAY MID LEVEL ENERGY IS FORECAST TO RAPIDLY SHEER TO THE EAST OF THE AREA LATE SUNDAY MORNING. THE 12Z MODEL SUITE ALL SUGGEST THE ASSOCIATED MID LEVEL ASCENT WILL RESIDE ALONG THE 1-69 CORRIDOR INTO THE THUMB REGION BY 12Z BEFORE QUICKLY WANING BY NOON. BOTH NAM AND GFS APPEAR TOO AGRESSIVE IN MOISTENING THE LOW LEVELS...SUGGESTING THAT WET BULB COOLING MAY BE STRONG ENOUGH TO KEEP ANY LINGERING MORNING PRECIP AS LIGHT SNOW. UPSTREAM OBSERVATIONS DO HOWEVER SUPPORT MODEL SOLUTIONS WHICH BRING A POST FRONTAL LOW STRATUS DECK INTO THE AREA FOLLOWING THE PASSAGE OF A WEAK SURFACE COLD FRONT. THESE LOW CLOUDS ARE EXPECTED TO ENVELOPE THE TRI CITIES AND THUMB BY DAYBREAK...THEN OVERSPREAD METRO DETROIT EARLY SUN AFTERNOON. OVERALL WEAK POST FRONTAL COLD AIR ADVECTION WILL SUPPORT SUN MAX TEMPS IN THE MID/UPPER 30S ACROSS THE NORTH AND LOW 40S SOUTH OF THE I-96/696 CORRIDOR. THE DEPTH OF THE POST FRONTAL COLD AIR SUN AFTERNOON WILL BE GREATER OVER LAKE HURON...WHICH WILL RESULT IN A DEEPENING CONVECTIVE DEPTH OVER THE LAKE. MODEL SOLUTIONS SUGGEST A GOOD RESPONSE OFF THE LAKE...ENOUGH TO SUPPORT A CHANCE OF SNOW SHOWERS OVER THE THUMB SUN AFTERNOON INTO SUNDAY EVENING AS THE FLOW TURNS TOWARD THE NE. THE EXPECTED DEGREE OF VARIABILITY IN THE LOW LEVEL WIND DIRECTION DOES NOT SUPPORT A PROLONGED CONVERGENT BAND...SO FORECAST ACCUMS WILL BE KEPT MINIMAL. MID LEVEL SUBSIDENCE WILL LOWER INVERSION HEIGHTS SUN NIGHT AND WILL MAINTAIN THE LOW STRATUS OVER THE REGION. CONTINUED LOW LEVEL MOISTURE FLUX UNDER THE NE FLOW MAY HOWEVER SUPPORT SOME DRIZZLE SUN NIGHT INTO MON MORNING OVER A GOOD PORTION OF SE MI. CONFIDENCE IS NOT QUITE HIGH ENOUGH TO ADD DRIZZLE TO THE ZONE/GRIDS AT THIS POINT...BUT IS SOMETHING LATER SHIFTS WILL HAVE TO MONITOR. AMPLE LOW CLOUDS AND WEAK LOW LEVEL THERMAL ADVECTION IS LIKELY TO HOLD TEMPS IN THE 30S SUN NIGHT INTO MON MORNING. A LOW AMPLITUDE MID LEVEL TROUGH IS FORECAST TO TRAVERSE THE OHIO VALLEY ON MONDAY. DESPITE THE OVERALL WEAK FORCING WITH THIS FEATURE...MODEL SOLUTIONS DO SUGGEST A HEALTHY SURGE OF MID LEVEL MOISTURE INTO SRN MI. THIS COUPLED WITH THE EXPECTED STRATUS AND WEAK LARGE SCALE ASCENT MAY BE ABLE TO GENERATE A FEW LIGHT SNOW AND/OR RAIN SHOWERS. SOUTHEAST MICHIGAN CONTINUES TO BE ON A ROLLER COASTER AS FAR AS TEMPERATURES ARE CONCERNED WITH TEMPS WARMING THROUGH THURSDAY BEFORE COOLING OFF BY THE WEEKEND. UPPER LEVEL RIDGE WILL WORK INTO THE AREA TUESDAY HELPING TO KEEP THINGS ON THE DRIER SIDE. PRECIP CHANCES START TO INCREASE WEDNESDAY AS A LOW TRAVERSES OVER THE NORTHERN GREAT LAKES. SOUTHERLY FLOW OUT AHEAD OF THIS SYSTEM WILL HELP TO BRING IN MOISTURE AND WARMER AIR. PRECIP TYPE WILL LIKELY START OFF AS SNOW BEFORE QUICKLY TRANSITIONING TO ALL RAIN AS WARMER TEMPS OVERSPREAD THE AREA. BETTER CHANCE FOR MEASURABLE PRECIP WILL COME THURSDAY INTO FRIDAY AS ANOTHER LOW DEVELOPS AND MOVES TOWARDS THE GREAT LAKES. CURRENTLY THIS LOW LOOKS TO TRACK SOUTH OF MICHIGAN WHICH WOULD PUT THE CWA IN THE COLD SECTOR WITH SNOW BEING THE MAIN PRECIP TYPE. COOLER TEMPS MAKE A RETURN NEXT WEEKEND AS WESTERLY FLOW INCREASES OVER SOUTHEAST MICHIGAN. MARINE... THE SOUTHERLY WINDS WILL DIMINISH DURING THE COURSE OF THE EVENING AS THE GRADIENT RELAXES. THIS WILL OCCUR AS A WEAK AREA OF LOW PRESSURE EXPANDS ACROSS LAKE HURON TONIGHT. THIS LOW WILL ADVANCE INTO ONTARIO ON SUNDAY WHICH WILL CAUSE THE WINDS TO TURN NORTHEASTERLY OVER LAKE HURON. WIND SPEEDS WILL INCREASE DURING THE AFTERNOON. GUSTS SHOULD REMAIN AT OR BELOW 25 KNOTS. THE GRADIENT WILL THEN RELAX BY MONDAY. WEAK HIGH PRESSURE WILL RESULT IN LIGHT WINDS INTO WEDNESDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......JVC AVIATION.....RBP SHORT TERM...CB LONG TERM....SC/SS MARINE.......SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
602 PM CST SAT NOV 30 2013 .SHORT TERM...(THIS AFTERNOON THROUGH SUNDAY) ISSUED AT 1135 AM CST SAT NOV 30 2013 VERY BENIGN PERIOD OF THE FORECAST. A WEAK CDFNT WILL CONTINUE TO DROP SE ACRS THE REGION WITH A TRAILING MIDLVL SHORTWAVE TROF AXIS. IT IS WITH THIS AXIS THAT MID-TO HIGH-LEVEL CLOUDS HAVE SLIPPED INTO THE REGION. HOWEVER...SAID CLOUDS WILL EFFECTIVELY SLIP ON OUT TNGT AS WEAK HIGH PRES SLIDES ACRS THE REGION OVERNIGHT THRU THE FIRST HALF OF SUNDAY. SKIES WILL MAINLY CLEAR OUT...BUT WITH WEAK FLOW ALOFT AND SFC HIGH PRES FORCING WINDS TO DROP TO LGT/VRBL...IF NOT CALM...MOISTURE TRANSPORT OUT OF THE AREA WILL BE NEARLY NON-EXISTENT. THIS WILL TRANSLATE TO THE DEVELOPMENT OF LOW CLOUDS AND/OR FOG NEAR DAYBREAK SUN MRNG. THE LOW CLOUDS WILL THEN SCOUR OUT DURG THE DAY TMRW...BUT MIDLVL DECKS WILL REMAIN SO MOCLDY CONDS ARE EXPECTED BY LATE SUN AFTN. MILD TEMPS WILL REMAIN IN PLACE THRU THE WEEKEND WITH NIL TEMP ADVECTION. LOWS TNGT WILL DROP TO THE MID-TEENS TO LWR 20S FOLLOWED BY HIGHS ON SUN THAT WILL HIT THE LOW-MID 30S. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 346 PM CST SAT NOV 30 2013 THE LONG TERM REMAINS A CHALLENGE WITH RESPECT TO THE DEEP UPPER LOW CURRENTLY DROPPING SOUTHWARD ACROSS WESTERN BRITISH COLUMBIA. THE NAM AND GFS TODAY TAKE A MAJOR PIECE OF THE UPPER LOW DUE EAST ONCE IT REACHES WASHINGTON STATE ON MONDAY... WHILE THE ECMWF DRIVES IT FURTHER SOUTH. THE GFS HAS THE UPPER LOW REACHING MN BY TUESDAY EVENING... WHILE THE ECMWF HOLDS MOST OF THE ENERGY BACK IN IDAHO WITH DOWNSTREAM RIDGING ACROSS. HPC/WPC DISMISSED THE 12Z SOLUTIONS OF THE NAM AND GFS AND PREFERRED THE DIGGING ECWMF DUE TO THE BUILDING RIDGE OVER AK. THE ECMWF FORECAST HAS REMAINED VERY CONSIST WITH THE HANDLING OF THE UPPER LEVEL OVER THE PAST 3 RUNS (36 HOURS) WITH EVEN THE GEM TODAY COMING MORE IN LINE WITH THE ECMWF. THEREFORE... MUCH OF WHAT WAS DONE TODAY WAS MORE OF A BLEND WITH EC/GEM GUIDANCE. THERE ARE DEFINITELY SOME CONCERNS IN THE UPCOMING FORECAST. LIGHT SNOW IS STILL EXPECTED SUNDAY NIGHT AND MONDAY AS RIPPLES OF UPPER LEVEL ENERGY PASS ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY REGION... IN CONCERT WITH A STEADY STREAM OF LOW LEVEL WAA. THE LIGHT SNOW SUNDAY NIGHT IS MAINLY CONFINED TO THE MN CWA WITH A WEAKENING TREND TO THE EAST EARLY ON MONDAY AS THE LOW LEVEL UPGLIDE DIMINISHES. ANOTHER SURGE OF SNOW ARRIVES FROM THE DAKOTAS MONDAY NIGHT... WITH AN INCH OR TWO LIKELY ACROSS CENTRAL MN AND ADJOINING AREAS OF WEST CENTRAL WI. THINGS BECOME MORE INTERESTING FROM TUESDAY INTO WEDNESDAY AS SURFACE LOW PRESSURE TAKES SHAPE IN EASTERN SD AND ADVANCES TO NEAR DULUTH BY WEDNESDAY EVENING. TUESDAY AFTERNOON AND TUESDAY NIGHT COULD BE A PERIOD FOR SNOW ACCUMULATION IN THE 3 TO 5 INCH RANGE ACROSS CENTRAL MN PER THE ECMWF. THE IS THE MAIN CONCERN IN THE FORECAST AS THE POTENTIAL SNOW ACCUMULATIONS WILL NEED TO BE MONITORED. WHILE THIS IS OCCURRING... IT WILL BE WARMING IN THE LOW LEVELS ACROSS SOUTHERN MN WITH A CHANGEOVER TO RAIN TUESDAY AFTERNOON. THE ECMWF SUGGESTS IT COULD STAY ALL RAIN ACROSS SOUTH CENTRAL AND SE MN TUESDAY NIGHT WITH DEW POINTS RISING INTO THE MIDDLE 30S. WE DIDN/T PUSH THINGS THAT FAR TODAY WITH THE GEM ON THE COOLER SIDE OF THE ENVELOPE. WITH THE LOW LIFTING NORTHEAST ACROSS CENTRAL MN ON WEDNESDAY... ARCTIC AIR SHOULD BEGIN SURGING INTO SW MN BY AFTERNOON AND ACROSS THE REMAINDER OF THE FA WEDNESDAY EVENING. WINDY AND MUCH COLDER CONDITIONS WILL OCCUR IN THE WAKE OF THE ARCTIC FRONT WEDNESDAY NIGHT. TEMPERATURES WILL BE STEADY OR SLOWLY FALLING ON THURSDAY ALONG WITH A BRISK WEST TO NORTHWEST WIND. THE COLD TEMPERATURES WILL REMAIN ACROSS THE REGION THROUGH SATURDAY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 602 PM CST SAT NOV 30 2013 IFR/LOW MVFR CEILINGS MEANDER FROM KDVL THROUGH KAXN TO KMZH AND KHYR EARLY THIS EVENING. THE CEILINGS ARE IN THE WAKE OF A COLD FRONT. THEY ARE DROPPING SOUTH NEAR 17 KNOTS. THE RAP AND HRRR HAVE A GOOD HANDLE ON THE SITUATION AND THEREFORE DROVE THEM ON SOUTH THROUGH ALL BUT KRWF THIS EVENING. SOME MVFR VISIBILITY IN BR POSSIBLE AROUND DAYBREAK SUNDAY. THE CEILINGS SHOULD BREAK UP IN THE MORNING... BUT WITH RIDGING BUILDING IN...THEY MAY LINGER LONGER ACROSS EASTERN MN AND WEST CENTRAL WI. THE DISSIPATION MAY NEED TO BE ADJUSTED IN THE NEXT ISSUANCE. LIGHT NW WINDS OVERNIGHT GRADUALLY BECOMING ESE SUNDAY AFTERNOON. KMSP...MVFR CEILINGS ARRIVING FROM THE NORTH IN THE 05Z-06Z TIME FRAME. SOME CONCERN THAT THEY MAY DROP BELOW 010 FROM 10Z- 14Z ALONG WITH SOME 5-6SM BR. VFR CEILINGS EXPECTED TO RETURN BY LATE MORNING BUT THIS COULD GET STRETCHED INTO THE AFTERNOON WITH HIGH PRESSURE AND A LIGHT WIND FIELD OVERHEAD. /OUTLOOK FOR KMSP/ SUN NGT...VFR...POSSIBLY MVFR CIGS/-SN LATE. WINDS ESE 5 KTS. MON...MVFR OR LOWER CIGS/VSBYS IN -SN. SE WINDS 10 KTS. TUE...IFR/MVFR CIGS IN -SN...POSSIBLY MIXED WITH RA BY AFTN. SE 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JPC LONG TERM...RAH AVIATION...RAH
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
948 PM EST SAT NOV 30 2013 .SYNOPSIS... HIGH PRESSURE OVER THE NORTH COUNTRY THIS AFTERNOON AND TONIGHT WILL GIVE WAY TO AN UPPER LEVEL LOW PRESSURE SYSTEM...WHICH WILL BRING WINTRY CONDITIONS TO THE AREA SUNDAY INTO PORTIONS OF NEXT MONDAY. A COASTAL LOW COULD AFFECT PORTIONS OF THE NORTH COUNTRY NEXT TUESDAY AND TUESDAY NIGHT...AND YET ANOTHER SYSTEM WEDNESDAY NIGHT INTO NEXT THURSDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 948 PM EST SATURDAY...EARLIER BURST OF WARM AIR ADVECTION DRIVEN LIGHT SNOWS MOVING ACROSS NORTHERN AND CENTRAL VERMONT HAS MOVED INTO NEW HAMPSHIRE AT THIS HOUR. RECENT OBSERVATIONS AND MODEL TRENDS SUGGEST THE PROSPECT FOR ADDITIONAL LIGHT SNOW THROUGH THE REST OF THE EVENING LOOKS TO BE LIMITED. THE STRONGEST 925-850 MB WARM ADVECTION AND ASSOCIATED LIFT IS TO OUR EAST...AND THE UPSTREAM SHORTWAVE TROUGH DOESN`T LOOK IMPRESSIVE. IN FACT THE NAM/WRF SHOW THE SHORTWAVE MORE OR LESS SHEARING OUT OVER NORTHERN NEW YORK TOWARDS MORNING. SO I`VE GONE AHEAD AND ADJUSTED TIMING OF LIGHT SNOW BACK TO 09-10Z FOR THE SAINT LAWRENCE VALLEY AND THE ADIRONDACKS...AND AROUND 12Z FOR THE FAR NORTHERN CHAMPLAIN VALLEY AND NORTHERN VERMONT. THIS TIMING ALSO IS SUPPORTED BY RECENT HRRR AND NAM/WRF REFLECTIVITY DATA. TEMPERATURES REMAIN GENERALLY IN THE MID TO UPPER 20S...AND UNDER A DECK OF LOW TO MID-LEVEL CLOUDINESS AS WELL AS SOUTH WINDS...FEEL THAT TEMPERATURES ARE LIKELY TO HOVER OR RISE A FEW DEGREES TOWARDS MORNING. LOWS IN MOST LOCATIONS HAVE ALREADY BEEN REACHED EXCEPT FOR THE NORTHEAST KINGDOM WHICH SHOULD TAKE PLACE BEFORE MIDNIGHT. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 237 PM EST SATURDAY...GOING INTO SUNDAY...SHORTWAVE AIDED BY A WEAK INVERTED TROUGH...WILL BRING LIGHT SNOWFALL TO THE AREA. FOCUS OF MOST PRECIP THRU THE DAY WILL BE ACROSS NORTHERN ZONES DUE TO LACK OF FORCING INTO THE AREA. WK RIDGING ALONG THE COAST SUN NGT/EARLY MONDAY WILL ALLOW FOR SHIFT OF UPPER LEVEL WINDS FROM MORE WESTERLY TO SOUTHWESTERLY FOR MON/MON NGT. SNOWFALL AMTS ACROSS THE CWA FOR THIS EVENT WILL RANGE FROM A D-1" IN VALLEY LOCALES EAST OF THE DACKS...AND 1-2" FOR DACKS/SLV AND NC NE VT. HIGHER AMTS IN THE ST LAW VALLEY TOWARDS TAIL-END OF EVENT AID BY SW FLOW BRINGING SOME LK ONTARIO MOISTURE INTO THE AREA. LINGERING -SW FOR MON/MON NGT ON TAP AS BROAD SW FLOW OVER THE CWA WITH UPPER LEVEL TROUGH TO OUR WEST AND COASTL SYSTEM WORKING UP THE EAST COAST. AS A RESULT OF W/SW SFC FLOW...WAA REMAINS INTACT WITH A GRADUAL INCR IN HIGHS THRU THE PERIOD...AND ABV NORMAL LOWS DUE TO CLDS AND SFC WINDS. HIGHS WILL RANGE IN THE LOW/MID 30S AND LOWS IN THE 20S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 351 PM EST SATURDAY...ECMWF AND GFS MODELS SHOWING TIMING DIFFERENCES THROUGH THE PERIOD WITH THE GFS MODEL A BIT FASTER WITH THE MOVEMENT OF SYSTEMS. THUS...GIVEN TIMING DIFFERENCES...FORECASTER CONFIDENCE IS ONLY FAIR AT THIS TIME. HOWEVER...GIVEN DIFFERENCES...HAVE LEANED TOWARD THE SLOWER ECMWF SOLUTION THROUGH THE PERIOD...AS THIS MODEL TENDS TO DO BETTER IN THE EXTENDED TIME RANGE. ON TUESDAY...GFS MODEL DEVELOPS SURFACE LOW SOUTH OF CAPE COD EARLY TUESDAY AND THEN SWINGS IT EAST SOUTH OF NOVA SCOTIA BY TUESDAY EVENING. GFS BRINGS SNOW SHOWERS ACROSS VERMONT ON TUESDAY...WHILE THE ECMWF HAS THIS FEATURE FURTHER EAST. MODELS DO SHOW AN UPPER TROUGH WILL ALSO APPROACH FROM THE WEST ON TUESDAY...SO WILL KEEP IN LOW CHANCE POPS FOR TUESDAY AND TUESDAY NIGHT. ECMWF MODEL SHOWING AN UPPER RIDGE TO BUILD INTO THE REGION BY WEDNESDAY AFTERNOON AND REMAINING THROUGH MIDDAY ON THURSDAY...WHILE THE GFS MODEL TENDS TO BRING MOISTURE FROM A FRONTAL SYSTEM INTO THE REGION BY WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT...AND THEN EAST OF THE REGION BY THURSDAY. ECMWF HAS THIS FEATURE MUCH FURTHER WEST ACROSS THE WESTERN GREAT LAKES WITH A STRONG UPPER RIDGE OVER THE REGION WEDNESDAY NIGHT AND THURSDAY. THUS...HAVE GONE WITH SLOWER ECMWF TIMING AND WILL HOLD OFF BRINGING MOISTURE FROM THIS NEXT FRONTAL SYSTEM UNTIL LATE THURSDAY AFTERNOON AND THURSDAY NIGHT. ECMWF AND GFS MODELS BRING MOISTURE NORTHEAST INTO THE REGION THURSDAY NIGHT AND FRIDAY...SO HAVE CHANCE POPS FOR RAIN OR SNOW SHOWERS. MODELS SHOWING SIGNIFICANT DIFFERENCES FRIDAY NIGHT AND SATURDAY WITH THE ECMWF MUCH SLOWER WITH THE MOVEMENT OF THE FRONTAL SYSTEM...WHILE THE GFS IS MORE PROGRESSIVE AND BRINGS MOST PRECIPITATION TO AN END FRIDAY NIGHT AND SATURDAY. THE ECMWF MODEL HAS THE FRONTAL SYSTEM PARALLEL TO THE UPPER FLOW AND THUS IS SLOWER. HAVE LEANED TOWARD THE SLOWER ECMWF MODEL AND WILL KEEP IN CHANCE POPS FOR PRECIPITATION FRIDAY NIGHT AND SATURDAY. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... THROUGH 00Z MONDAY...BKN-OVC CONDITIONS EXPECTED THROUGH THE TAF PERIOD. WARM FRONT CROSSING VT 00-03Z WILL BRING BRIEF PERIOD OF SNOWFALL BTV/MPV/RUT...BUT IT APPEARS CIGS/VSBY WILL ONLY BRIEFLY DROP INTO MVFR RANGE BEFORE IMPROVING BACK TO OVC080-120 FOR THE BALANCE OF THE OVERNIGHT PERIOD. MODERATE GRADIENT FLOW IN PLACE BETWEEN DEPARTING SFC HIGH IN THE GULF OF MAINE AND SFC LOW OVER LAKE HURON. THIS WILL BRING SOUTH WINDS 10-15KTS WITH A FEW GUSTS 20-22 KTS THRU 12Z SUNDAY. GRADIENT GRADUALLY SLACKENS DURING THE DAYLIGHT HRS SUNDAY...SO WINDS SHOULD SUBSIDE TO 5-10 KTS AFTER 12Z SUNDAY. WEAKENING SFC TROUGH CROSSES THE REGION 15Z SUN THRU 00Z MONDAY...BRINGING MVFR/BRIEF IFR CEILINGS/VSBY AND SOME VERY LIGHT SNOW TO THE TAF SITES MAINLY SUNDAY AFTN. LIGHT SNOW ACCUMULATION POSSIBLE ALL TAF LOCATIONS...GENERALLY DUSTING-1" WITH MINOR IMPACTS TO AVIATION OPERATIONS SUNDAY AFTN. OUTLOOK 00Z MONDAY THROUGH THURSDAY... 12Z MONDAY THROUGH 18Z WEDNESDAY...MAINLY VFR...BUT WITH A CHANCE FOR SOME SNOW SHOWERS AND MVFR CONDITIONS. 18Z WEDNESDAY THROUGH 00Z FRIDAY...MAINLY VFR AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION. && .MARINE... AS OF 140 PM SATURDAY...SOUTHERLY WINDS FUNNELING UP THE CHAMPLAIN VALLEY AND OVER THE LAKE HAVE STRENGTHENED TO THE LEVEL THAT A LAKE WIND ADVISORY IS NEEDED. WINDS OF AROUND 20-25 KNOTS WITH GUSTS AROUND 30 KNOTS ARE EXPECTED FOR THE REMAINDER OF THIS AFTERNOON AND THROUGHOUT THE OVERNIGHT HOURS. THE STRONGEST OF THE WINDS ARE EXPECTED ACROSS THE BROAD LAKE, AND WILL PRODUCE WAVES INTO THE 3 TO 5 FOOT RANGE. WINDS WILL BE A BIT WEAKER AROUND THE ISLANDS, AS WILL WAVES BE SMALLER. THESE STRONG SOUTHERLY WINDS ARE EXPECTED TO QUICKLY DIMINISH SHORTLY AFTER SUNRISE SUNDAY. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...JN NEAR TERM...JN/LOCONTO SHORT TERM...JN LONG TERM...WGH AVIATION...BANACOS/WGH MARINE...
AREA FORECAST DISCUSSION
NWS BISMARCK ND
108 AM CST FRI NOV 29 2013 .UPDATE... ISSUED AT 100 AM CST FRI NOV 29 2013 DECREASED CLOUDS A BIT COMPARED TO WHAT WAS IN THE FORECAST FOR THE REST OF THE OVERNIGHT. WITH WARM AIR ADVECTION OVERNIGHT JUST OFF THE SURFACE...AHEAD OF THE SURFACE WARM FRONT...THERE IS A CHANCE THAT LOWER CLOUDS COULD FORM...AND SOME MODEL GUIDANCE SHOWS THIS. HOWEVER...THE TREND OVER THE PAST FEW HOURS HAS BEEN FOR THE LOW CLOUDS TO DECREASE...NOT INCREASE. MID CLOUD IS ALSO WORKING ITS WAY THROUGH NORTHEAST MONTANA AND INTO NORTHWEST NORTH DAKOTA. BASICALLY VARIABLE CLOUDS OVERNIGHT...PARTLY CLOUDY AND TIMES...MOSTLY CLOUDY AT OTHER TIMES. BASED ON TEMPERATURE TRENDS...AND WITH SOUTHEAST SURFACE WIND 5 TO 15 MPH...MAYBE MORE LIKE 10 TO 15 MPH...WILL NOT EXPECT TEMPERATURES TO FALL MUCH FROM WHERE THEY ARE AS OF THIS WRITING. WIND WILL MAKE IT FEEL 5 TO 10 DEGREES LOWER THAN WHAT THE THERMOMETER SHOWS. NO CHANGES TO THE REST OF THE SHORT TERM FOR NOW. UPDATE ISSUED AT 851 PM CST THU NOV 28 2013 CLOUDS AND TEMPERATURES CONTINUE TO BE THE MAIN ISSUES TONIGHT. COOL HIGH PRESSURE ACROSS MINNESOTA WITH A WARM FRONTAL BOUNDARY ACROSS MONTANA. THE TREND HAS BEEN CLEARING SKIES BUT LATEST SATELLITE PICTURES SUGGEST CLOUDS MAYBE REFORMING ACROSS CENTRAL NORTH DAKOTA NORTH OF LAKE SAKAKAWEA. NOW WILL BE TRENDING THE CLOUDS BACK INTO THE PICTURE TONIGHT. ALSO TEMPERATURES MAY HIT THEIR LOWS LATE THIS EVENING OR EARLY AFTER MIDNIGHT THEN BECOME STEADY OR RISE A BIT BY MORNING...ESPECIALLY JAMES RIVER VALLEY NORTH TO THE DEVILS LAKE BASIN. DO NOT SEE ANY PRECIP IN THE FORECAST FOR TONIGHT AS THE FLURRIES FROM THURSDAY AFTERNOON HAVE ENDED. UPDATE ISSUED AT 541 PM CST THU NOV 28 2013 AT 5 PM CST...SURFACE HIGH PRESSURE EXTENDED ACROSS THE EASTERN DAKOTAS. A SURFACE TROUGH AND ASSOCIATED WARM FRONT EXTENDED THROUGH CENTRAL MONTANA. THE THIN LAYER OF STRATUS HAS ERODED IN WEAK LOW LEVEL WARM ADVECTION...LEAVING NARROW BANDS OF CLOUDS ACROSS CENTRAL NORTH DAKOTA WITH THE WEST GENERALLY MOSTLY CLEAR. CURRENT THINKING IS THE CLOUDS WILL EVENTUALLY BACK FILL IN WITH SHALLOW COOL AIR IN PLACE AS THE WARM FRONT MOVES EAST. SOME UNCERTAINTY HERE ALSO...AS LOW LEVEL WARM ADVECTION AT H850 MAY SUPPRESS CLOUDS LATER TONIGHT. BUT WENT WITH AN INCREASE IN CLOUDS THROUGH MIDNIGHT....THEN CLOUDY AFTER MIDNIGHT. CURRENT TEMPERATURES AND WINDS SEEM OK FOR NOW. && .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 306 PM CST THU NOV 28 2013 THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE SKY COVER TONIGHT AND IMPACT ON TEMPERATURES. PORTIONS OF THE STRATUS DECK HAVE ERODED ACROSS THE FORECAST AREA THIS AFTERNOON. RAP 925MB RELATIVE HUMIDITY HAS THIS MODELED RELATIVELY WELL AND SUGGEST THAT STRATUS SHOULD FILL BACK IN THIS EVENING AND OVERNIGHT. TEMPERATURES WILL LIKELY DROP QUICKLY THIS EVENING IN CLOUD FREE AREAS...BEFORE THE STRONGER SE WINDS DEVELOP. THE STRONGER GRADIENT WILL BE LOCATED OVER THE WEST AND HAVE KEPT OVERNIGHT LOWS RELATIVELY MILD...IN THE TEENS TO LOWER 20S. EAST/NORTHEAST PORTIONS OF THE FORECAST AREA...FROM THE TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY...SHOULD BE ABLE TO GET INTO THE SINGLE DIGITS. HOURLY TRENDS WILL LIKELY NEED TO BE UPDATED THIS EVENING. ON FRIDAY...STRONGER WARM AIR ADVECTION WILL KICK IN...WITH HIGHS IN THE MID 20S NORTHEAST TO LOWER 40S SOUTHWEST. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 306 PM CST THU NOV 28 2013 THE HIGHLIGHT OF THE EXTENDED FORECAST IS THE RETURN OF ARCTIC AIR AND THE POTENTIAL FOR WIDESPREAD ACCUMULATING SNOW NEXT WEEK. THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON A SIGNIFICANT UPPER LEVEL LOW COMING ONSHORE TO THE PACIFIC NORTHWEST ON MONDAY. THEREAFTER...UNCERTAINTY INCREASES IN REGARDS TO THE EVOLUTION AND PROPAGATION OF THIS LOW ACROSS THE INTERMOUNTAIN WEST AND POTENTIALLY INTO THE NORTHERN PLAINS LATE TUESDAY AND INTO WEDNESDAY. THE 12 UTC ECMWF CONTINUES THE TREND OF ITS PREVIOUS RUNS OVER THE PAST 24 HOURS OF THE DEEPEST LOW YIELDING SIGNIFICANT QPF AND SNOW ACROSS THE NORTHERN PLAINS TUESDAY INTO WEDNESDAY. THE 12 UTC GFS HAS TRENDED MORE TOWARDS THE ECMWF...HOWEVER...IS NOT AS DEEP WITH LESSER QPF...MUCH LIKE THE 12 UTC GEM. THE ECMWF HAS BEEN THE MOST CONSISTENT AND IS SUPPORTED BY THE GEFS MEAN...AND FAVORED BY WPC. THUS...WILL CONTINUE TO MONITOR THE POTENTIAL FOR ACCUMULATING SNOW NEXT WEEK. NO MATTER THE MODEL...ARCTIC AIR IS FORECAST TO OVERTAKE THE NORTHERN PLAINS ONCE AGAIN TUESDAY THROUGH THE END OF NEXT WEEK WITH A PATTERN SHIFT TO BROAD WESTERN AND CENTRAL CONUS UPPER LEVEL TROUGHING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT) ISSUED AT 100 AM CST FRI NOV 29 2013 THE FIRST HALF OF THIS TAF FORECAST PERIOD IS COMPLICATED BECAUSE OF UNCERTAINTY CONCERNING THE CEILING FORECAST. THERE HAVE BEEN PATCHES OF MVFR CIGS ALONG THE MONTANA BORDER... MOVING NORTHWEST IN SOUTHEAST SURFACE FLOW...AND MVFR CIGS FROM SOUTHEAST OF KMOT THROUGH THE KJMS AREA. THE TREND HAS BEEN FOR THEM TO BE DECREASING RATHER THAN INCREASING IN COVERAGE. HOWEVER...WITH SHALLOW COLD AIR IN PLACE...A SURFACE WARM FRONT IN EASTERN MONTANA...AND WARM AIR ADVECTION JUST OFF THE DECK...WITH AN INVERSION EXPECTED OVER MOST OF THE AREA BY DAYBREAK FRIDAY... THE EXPECTATION THAT MVFR CIGS WILL REDEVELOP IS SUPPORTED. TIMING AND THE EXTENT OF THE CLOUDS ARE UNCERTAIN. CURRENT TAFS USED TEMPO GROUPS TO ACCOUNT FOR THE REFORMATION OF LOWER CLOUDS. CONDITIONS WILL IMPROVE TO VFR AGAIN FRIDAY AFTER 16-18Z. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JPM LONG TERM...AYD AVIATION...JPM
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1003 PM CST SAT NOV 30 2013 .UPDATE... ISSUED AT 1002 PM CST SAT NOV 30 2013 FORECAST FAIRLY MUCH IN CONTROL THIS EVENING...WITH SOME MINOR CHANGES MAINLY TO TRENDS IN TEMPERATURES...AND TO INCREASE CLOUD COVER OVERNIGHT. FOR MOST...MID CLOUDS WILL BE HARD TO SHAKE TONIGHT WITH MID LEVEL BOUNDARY STALLING ACROSS THE AREA WITH STRONGER WAVE APPROACHING THE AREA DURING THE AFTERNOON AND EVENING ON SUNDAY. ALSO HAVE TO KEEP AN EYE ON LOWER CLOUDS WHICH HAVE BEEN STEADILY PRESSING SOUTH AND SOUTHWEST ACROSS EASTERN NORTH DAKOTA AND NORTHERN MINNESOTA. NAM/GFS ARE DOING THEIR TYPICAL HORRID JOB IN DEFINING THEM...AND IF DEPENDING ON RAP TO PICK UP TREND...WOULD THREATEN TO DRIFT INTO KMWM/KMML/KBKX AREAS BY AROUND 12Z. DID NUDGE UP OVERNIGHT LOWS SOMEWHAT WITH INCREASED SKYCOVER. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 315 PM CST SAT NOV 30 2013 HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT WITH WINDS RAPIDLY BECOMING LIGHT AFTER SUNSET. THERE WILL BE A LOT OF BREAKS IN THE CLOUDS...ESPECIALLY ALONG AND SOUTH OF I90 SO TEMPERATURES COULD FALL QUICKLY IN THE EARLY EVENING. AS THE HIGH MOVES TO THE EAST OVERNIGHT AND THE 850 MB THERMAL GRADIENT MOVE INTO EASTERN SD... CLOUDS WILL INCREASE ACROSS CENTRAL SD AND INTO PORTIONS OF EASTERN SOUTH DAKOTA. HOW FAST THESE CLOUDS MOVE IN WILL HAVE A LARGE IMPACT ON TEMPERATURES. EXPECTING CLOUDS TO REACH KHON BY MIDNIGHT BUT NOT GET INTO MUCH OF NORTHWEST IOWA UNTIL SUNDAY MORNING. SO HAVE TEMPERATURES STAY IN THE MID 20S ALONG AND WEST OF THE JAMES RIVER WITH UPPER TEENS ALONG AND EAST OF I29. ON SUNDAY...MOST AREAS WILL BECOME OVERCAST AS MID CLOUDS OVERSPREAD THE REST OF THE AREA BY SUNDAY MORNING. THE SURFACE RIDGE WILL ALSO BE OVER MN AND IA MUCH OF THE DAY KEEPING WINDS LIGHT AND LIMITING MIXING AND RETURN OF WARM AIR AT LOW LEVELS. THIS WILL KEEP TEMPERATURES 10 DEGREES COOLER THAN TODAY WITH HIGHS IN THE 30S IN SW MN AND PORTIONS OF NW IA AND EAST CENTRAL SD. WARMEST TEMPERATURES WILL BE IN THE MISSOURI VALLEY IN THE LOWER TO MID 40S. A WEAK UPPER WAVE WILL MOVE INTO EASTERN SOUTH DAKOTA SUNDAY AFTERNOON. WHILE THE UPPER LEVEL FORCING FOR ASCENT IS THERE...THERE IS LITTLE LOW LEVEL FRONTOGENESIS OR MOISTURE WHICH WILL REALLY LIMIT PRECIPITATION. BUT WITH THE UPPER WAVE APPROACHING...DID CONTINUE WITH A SLIGHT CHANCE OF PRECIPITATION. TEMPERATURES WILL BE IN THE MID TO UPPER 30S WITH UPPER 20S DEW POINTS. THAT WOULD SUGGEST PRIMARILY A RAIN AND SNOW MIX TRENDING TOWARD ALL SNOW AFTER SUNSET WHEN TEMPERATURES FALL TOWARD FREEZING. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 315 PM CST SAT NOV 30 2013 THE LIGHT PRECIPITATION...IF IT DEVELOPS TO THE SURFACE...SHOULD CONTINUE TO DEVELOP EAST SOUTHEAST INTO SOUTHWEST MN AND PART OF NORTHWEST IA SUNDAY EVENING. AFTER A BRIEF PERIOD OF LOW LEVEL COOLING AND MIXED RAIN AND SNOW ON THE SOUTHWESTERN EDGE OF THE PRECIPITATION THREAT AREA...ANY PRECIPITATION SHOULD BE LIGHT SNOW. MODEL SOUNDINGS ON BUFKIT SHOW CONTINUED MARGINAL TEMPERATURES ALOFT THROUGH THE EVENING BUT FEEL ANY PRECIPITATION THAT DOES OCCUR WILL COOL THE AIR ENOUGH TO KEEP IT AS SNOW. NEVERTHELESS...TEMPERATURES SHOULD LEVEL OFF SUNDAY EVENING AFTER EARLY COOLING AND MAY RISE A BIT LATER IN THE NIGHT AS A WARMING PATTERN SLOWLY GETS GOING. AFTER THIS WAVE SLIDES EAST OF AREA LATE SUNDAY NIGHT...STILL DO NOT SEE ENOUGH SUPPORT TO MENTION PRECIPITATION FOR MONDAY. THE WARMING PICKS UP A LITTLE FOR MONDAY AND WITH SOME HEATING THROUGH AN ASSORTMENT OF HIGHER CLOUDS...MONDAY SHOULD BE MILD WITH HIGHS IN THE 40S...LOWER 50S SOUTHWEST. IT WAS GENERALLY AGREED EARLY ON TODAY THAT THE NAM AND GFS ARE PERFORMING POORLY ON THEIR RAPID ADVANCE OF THE NORTHERN UPPER LOW AND THE LEADING SURFACE LOW AND FRONT. THE EC AND CANADIAN ARE CLOSE AND APPEAR MORE CONSISTENT DURING THE LAST DAY OR SO WITH A DEEPER DIGGING OF THE UPPER TROUGH OVER THE WESTERN USA...AND A SLOWER ADVANCE OF THE SURFACE LOW AND FRONT. THEREFORE...EXPECT TUESDAY TO STILL BE MILD...NOT AS WARM AS MONDAY...WITH A CHANCE TO SLIGHT CHANCE PRECIPITATION THREAT BEING LIGHT RAIN. HAVE ACTUALLY BEGUN THIS FAR NORTH AS A SLIGHT CHANCE OF RAIN OR FREEZING RAIN MONDAY NIGHT. STILL DO NOT SEE CONCRETE SUPPORT FOR PRECIPITATION AS FAR EAST AS OUR AREA...BUT MOISTURE LEVELS DO INCREASE AND THE FLOW VERY SLOWLY BECOMES MORE FAVORABLE FOR SCATTERED LIGHT PRECIPITATION AHEAD OF THE FRONT AND LOW. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WILL SEE A BETTER CHANCE OF LIGHT PRECIPITATION ALONG WITH A TURN TO COLDER...WHICH SHOULD CHANGE ANY PRECIPITATION TO SNOW OVER MOST OF THE AREA BY LATE WEDNESDAY...EVEN ACCORDING TO THE EC AND CANADIAN. THE PROBLEM IS THAT OUR FORECAST AREA EVIDENTLY WILL NOT SEE MORE THAT AREAS OF LIGHT PRECIPITATION DURING THIS TIME AS MEAGER SUPPORT AND ADVECTION IS REPLACED BY THE STRONG COLD ADVECTION WHICH FAIRLY QUICKLY INCREASES IN DEPTH. THE BEST CHANCE OF LIGHT SNOW ACCUMULATIONS APPEARS TO BE IN THE FIRST HOURS AFTER THE AIR BECOMES COLD ENOUGH FOR SNOW. BUT POPS THROUGH THE PERIOD WILL STAY AT MOST IN THE CHANCE CATEGORY. WILL GO WITH THE EXTENDED GUIDANCE AND KEEP POPS BELOW MENTION THRESHOLD THURSDAY THROUGH SATURDAY...EXCEPT FOR SOME FLURRIES ON THURSDAY. THE EC WITH ITS SHARPER LARGE SCALE UPPER TROUGH INDICATES A THREAT OF STEADY LIGHT TO MODERATE SNOW DEVELOPING RIGHT AFTER THE FORECAST PERIOD...THAT IS NEXT SUNDAY AND MONDAY. THE OVERNIGHT 06Z GFS HAD A LITTLE SOMETHING LIKE THIS BUT THE 12Z RUN KEEPS ITS SPEEDY NATURE GOING THROUGH AND BEYOND THE EXTENDED PERIOD. AS THE COLD AIR ARRIVES THERE WILL BE SOME WIND...WITH WIND CHILLS GOING BELOW ZERO LATER THIS WEEK. A SNOW COVER COULD BRING COLDER TEMPERATURES AND PERHAPS THE NEED FOR A WIND CHILL ADVISORY BY THE START OF NEXT WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1002 PM CST SAT NOV 30 2013 FOR THE MOST PART...VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR TAF SITES THROUGH 06Z MON. A WEAK SYSTEM WILL BRING A LOW THREAT FOR SOME LIGHT PRECIPITATION INTO EASTERN SOUTH DAKOTA AFTER 21Z...BUT FOR NOW WILL KEEP CONDITIONS WITH MENTION LIMITED TO KHON AND KFSD...AND ALSO AS VFR CONDITIONS. LOWER CLOUDS WORKING SOUTHWEST IN THE SHORT TERM ARE NOT EXPECTED TO REACH KHON OR KFSD AT THIS TIME...BUT AREAS TOWARD KBKX/KMML COULD FIND SOME LIFR CEILINGS LATER TONIGHT AND EARLY SUNDAY MORNING. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...CHAPMAN SHORT TERM...SCHUMACHER LONG TERM... AVIATION...CHAPMAN
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
946 PM CST SAT NOV 30 2013 .UPDATE... CURRENT FORECAST IS IN GOOD SHAPE AND NO MAJOR CHANGES ARE NEEDED AT THIS TIME. CLOUD COVER WILL CONTINUE TO INCREASE THROUGH SUNDAY MORNING WITH THE THICKEST AND MOST PERSISTENT CLOUD COVER SPREADING NORTHEAST INTO THE ARKLATEX. A FAST MOVING WEAK UPPER DISTURBANCE WILL SWING THROUGH THE PLAINS TOMORROW AND MAY HELP TRIGGER A FEW SHOWERS ACROSS THE NORTHEAST COUNTIES ON THE LEADING EDGE OF THE BETTER MOISTURE. OTHERWISE IT WILL BE QUIET WITH CONTINUED WARMING TEMPERATURES INTO EARLY NEXT WEEK. DUNN && .AVIATION... /00Z TAFS/ TIMING CIG TRENDS OVERNIGHT INTO EARLY SUNDAY WILL BE CHALLENGING ALONG WITH BRIEF VSBY DROPS AROUND DAYBREAK WITH LOW LEVEL WINDS SLIGHTLY VEERED. VFR CIGS WILL CONTINUE ACROSS WACO AND AREAS SOUTH OF I-20 WHILE DFW METRO AIRPORTS ENCOUNTER MAINLY SCT LOW CLOUDS WITH OCCASIONAL BKN-OVC HIGH CLOUDINESS THROUGH MIDNIGHT. AFTER PERUSAL OF LATEST BUFR SOUNDING DATA AND RUC SOUNDINGS...IT APPEARS MVFR CIGS WILL NOT ARRIVE INTO DFW UNTIL BETWEEN 07-09Z DUE TO THE VEERED LOW LEVEL WINDS THROUGH 925MB. WILL BRING MVFR INTO WACO AN HOUR OR TWO SOONER WITHIN THE MORE MOIST LOW LEVEL ENVIRONMENT. IFR CONDITIONS WITH BRIEF MVFR VSBYS LOOK POSSIBLE BY DAYBREAK SUNDAY AT ALL TERMINALS WITH BOUNDARY LAYER WINDS ONLY SSW 10-15 KTS. WACO WILL BE A TAD SLOWER TO RISE SUNDAY DUE TO LIGHTER WINDS AND MORE MOISTURE VERSUS DFW. NEVERTHELESS...ALL TERMINALS WILL RISE INTO MVFR BY MID-LATE MORNING AND BACK TO VFR BY EARLY-MID AFTERNOON SUNDAY WITH MIXING/HEATING. S/SW WINDS 5-9 KTS OVERNIGHT WILL INCREASE TO BETWEEN 10-15 KTS ONCE AGAIN BY MIDDAY SUNDAY. NO PRECIPITATION IS EXPECTED. 05/ && .PREV DISCUSSION... /ISSUED 334 PM CST SAT NOV 30 2013/ A LOW LEVEL WARM AIR ADVECTION PATTERN WILL CONTINUE ACROSS NORTH TEXAS TONIGHT WITH THE RETURN OF STRATUS OVERNIGHT. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 40S IN THE NORTH TO THE MIDDLE 50S IN THE SOUTH. A SHORT WAVE TROUGH WILL TRANSLATE ACROSS THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY AND ALLOW A WEAK COLD FRONT TO CROSS THE RED RIVER. ALTHOUGH MOISTURE WILL BE LIMITED AND GENERALLY CONFINED TO THE LOWEST LEVELS OF THE ATMOSPHERE. A FEW SHOWERS/STORMS MAY ACCOMPANY THE SHORT WAVE...MAINLY ACROSS THE NORTHEASTERN ZONES WHERE MOISTURE AND INSTABILITY WILL BE THE MOST FAVORABLE. DRIER AND SLIGHTLY COOLER AIR WILL MOVE INTO NORTH TEXAS SUNDAY NIGHT AS WEAK SURFACE HIGH PRESSURE TEMPORARILY BUILDS INTO THE REGION. BY MONDAY...THE FRONT WILL BEGIN TO LIFT NORTHWARD IN RESPONSE TO A DEEPENING SURFACE TROUGH ACROSS THE CENTRAL HIGH PLAINS. LOW LEVEL WARM AIR ADVECTION WILL QUICKLY INCREASE MONDAY NIGHT AND TUESDAY AS THE SURFACE TROUGH CONTINUES TO DEEPEN AHEAD OF A DEVELOPING LONG WAVE TROUGH ACROSS THE WESTERN UNITED STATES. THE GFS AND THE ECMWF SOLUTIONS BEGIN TO DIFFER IN THE TUESDAY NIGHT/WEDNESDAY TIME FRAME. THE GFS SOLUTION MOVES A PIECE OF ENERGY EASTWARD ACROSS THE NORTHERN HIGH PLAINS AND GREAT LAKES AND ALLOWS A COLD FRONT TO SLIDE SOUTHWARD THROUGH THE CENTRAL PLAINS AND ACROSS NORTH TEXAS WEDNESDAY AFTERNOON/NIGHT. THE ECMWF SOLUTION KEEPS THE WESTERN TROUGH MORE CONSOLIDATED AND DIGS IT SOUTH...THUS KEEPING THE COLD FRONT NORTH OF THE REGION. WE WILL SIDE CLOSER TO THE ECMWF SOLUTION BASED ON RECENT MODEL PERFORMANCE WITH SIMILAR SYSTEMS. THEREFORE...WILL KEEP TEMPERATURES WARM ON WEDNESDAY AND NOT BRING THE FRONT THROUGH NORTH TEXAS UNTIL THURSDAY. WE WILL INCLUDE SOME WARM AIR ADVECTION SHOWERS IN THE THE FORECAST WEDNESDAY NIGHT AND INCREASE RAIN/THUNDERSTORM CHANCES WITH THE COLD FRONT ON THURSDAY. SOME POST FRONTAL RAIN IS EXPECTED THURSDAY NIGHT AND FRIDAY AS THE UPPER TROUGH MOVES EAST ACROSS THE REGION. TEMPERATURES FRIDAY MORNING SHOULD REMAIN ABOVE 32 DEGREES AND NO FREEZING RAIN OR WINTER PRECIPITATION IS EXPECTED AT THIS TIME. FRIDAY NIGHT AND SATURDAY WILL BE COLD WITH LOWS IN THE 20S AND 30S AND HIGHS FROM THE UPPER 30S TO THE MIDDLE 40S. 79 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 50 68 45 68 48 / 0 0 0 0 5 WACO, TX 50 67 45 67 48 / 5 5 0 0 5 PARIS, TX 48 63 46 66 45 / 0 20 5 5 5 DENTON, TX 49 68 39 68 44 / 0 0 0 0 5 MCKINNEY, TX 48 66 42 65 43 / 0 10 0 0 5 DALLAS, TX 52 66 46 67 49 / 0 10 0 0 5 TERRELL, TX 51 65 46 67 47 / 0 20 0 0 5 CORSICANA, TX 52 65 48 68 50 / 0 10 0 0 5 TEMPLE, TX 52 68 46 72 49 / 5 5 0 0 5 MINERAL WELLS, TX 47 70 39 69 39 / 0 0 0 0 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
545 PM CST SAT NOV 30 2013 .AVIATION... /00Z TAFS/ TIMING CIG TRENDS OVERNIGHT INTO EARLY SUNDAY WILL BE CHALLENGING ALONG WITH BRIEF VSBY DROPS AROUND DAYBREAK WITH LOW LEVEL WINDS SLIGHTLY VEERED. VFR CIGS WILL CONTINUE ACROSS WACO AND AREAS SOUTH OF I-20 WHILE DFW METRO AIRPORTS ENCOUNTER MAINLY SCT LOW CLOUDS WITH OCCASIONAL BKN-OVC HIGH CLOUDINESS THROUGH MIDNIGHT. AFTER PERUSAL OF LATEST BUFR SOUNDING DATA AND RUC SOUNDINGS...IT APPEARS MVFR CIGS WILL NOT ARRIVE INTO DFW UNTIL BETWEEN 07-09Z DUE TO THE VEERED LOW LEVEL WINDS THROUGH 925MB. WILL BRING MVFR INTO WACO AN HOUR OR TWO SOONER WITHIN THE MORE MOIST LOW LEVEL ENVIRONMENT. IFR CONDITIONS WITH BRIEF MVFR VSBYS LOOK POSSIBLE BY DAYBREAK SUNDAY AT ALL TERMINALS WITH BOUNDARY LAYER WINDS ONLY SSW 10-15 KTS. WACO WILL BE A TAD SLOWER TO RISE SUNDAY DUE TO LIGHTER WINDS AND MORE MOISTURE VERSUS DFW. NEVERTHELESS...ALL TERMINALS WILL RISE INTO MVFR BY MID-LATE MORNING AND BACK TO VFR BY EARLY-MID AFTERNOON SUNDAY WITH MIXING/HEATING. S/SW WINDS 5-9 KTS OVERNIGHT WILL INCREASE TO BETWEEN 10-15 KTS ONCE AGAIN BY MIDDAY SUNDAY. NO PRECIPITATION IS EXPECTED. 05/ && .PREV DISCUSSION... /ISSUED 334 PM CST SAT NOV 30 2013/ A LOW LEVEL WARM AIR ADVECTION PATTERN WILL CONTINUE ACROSS NORTH TEXAS TONIGHT WITH THE RETURN OF STRATUS OVERNIGHT. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 40S IN THE NORTH TO THE MIDDLE 50S IN THE SOUTH. A SHORT WAVE TROUGH WILL TRANSLATE ACROSS THE CENTRAL AND SOUTHERN PLAINS ON SUNDAY AND ALLOW A WEAK COLD FRONT TO CROSS THE RED RIVER. ALTHOUGH MOISTURE WILL BE LIMITED AND GENERALLY CONFINED TO THE LOWEST LEVELS OF THE ATMOSPHERE. A FEW SHOWERS/STORMS MAY ACCOMPANY THE SHORT WAVE...MAINLY ACROSS THE NORTHEASTERN ZONES WHERE MOISTURE AND INSTABILITY WILL BE THE MOST FAVORABLE. DRIER AND SLIGHTLY COOLER AIR WILL MOVE INTO NORTH TEXAS SUNDAY NIGHT AS WEAK SURFACE HIGH PRESSURE TEMPORARILY BUILDS INTO THE REGION. BY MONDAY...THE FRONT WILL BEGIN TO LIFT NORTHWARD IN RESPONSE TO A DEEPENING SURFACE TROUGH ACROSS THE CENTRAL HIGH PLAINS. LOW LEVEL WARM AIR ADVECTION WILL QUICKLY INCREASE MONDAY NIGHT AND TUESDAY AS THE SURFACE TROUGH CONTINUES TO DEEPEN AHEAD OF A DEVELOPING LONG WAVE TROUGH ACROSS THE WESTERN UNITED STATES. THE GFS AND THE ECMWF SOLUTIONS BEGIN TO DIFFER IN THE TUESDAY NIGHT/WEDNESDAY TIME FRAME. THE GFS SOLUTION MOVES A PIECE OF ENERGY EASTWARD ACROSS THE NORTHERN HIGH PLAINS AND GREAT LAKES AND ALLOWS A COLD FRONT TO SLIDE SOUTHWARD THROUGH THE CENTRAL PLAINS AND ACROSS NORTH TEXAS WEDNESDAY AFTERNOON/NIGHT. THE ECMWF SOLUTION KEEPS THE WESTERN TROUGH MORE CONSOLIDATED AND DIGS IT SOUTH...THUS KEEPING THE COLD FRONT NORTH OF THE REGION. WE WILL SIDE CLOSER TO THE ECMWF SOLUTION BASED ON RECENT MODEL PERFORMANCE WITH SIMILAR SYSTEMS. THEREFORE...WILL KEEP TEMPERATURES WARM ON WEDNESDAY AND NOT BRING THE FRONT THROUGH NORTH TEXAS UNTIL THURSDAY. WE WILL INCLUDE SOME WARM AIR ADVECTION SHOWERS IN THE THE FORECAST WEDNESDAY NIGHT AND INCREASE RAIN/THUNDERSTORM CHANCES WITH THE COLD FRONT ON THURSDAY. SOME POST FRONTAL RAIN IS EXPECTED THURSDAY NIGHT AND FRIDAY AS THE UPPER TROUGH MOVES EAST ACROSS THE REGION. TEMPERATURES FRIDAY MORNING SHOULD REMAIN ABOVE 32 DEGREES AND NO FREEZING RAIN OR WINTER PRECIPITATION IS EXPECTED AT THIS TIME. FRIDAY NIGHT AND SATURDAY WILL BE COLD WITH LOWS IN THE 20S AND 30S AND HIGHS FROM THE UPPER 30S TO THE MIDDLE 40S. 79 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 50 68 45 68 48 / 0 0 0 0 5 WACO, TX 52 67 45 67 48 / 5 5 0 0 5 PARIS, TX 48 63 46 66 45 / 0 20 5 5 5 DENTON, TX 49 68 39 68 44 / 0 0 0 0 5 MCKINNEY, TX 48 66 42 65 43 / 0 10 0 0 5 DALLAS, TX 52 66 46 67 49 / 0 10 0 0 5 TERRELL, TX 51 65 46 67 47 / 0 20 0 0 5 CORSICANA, TX 52 65 48 68 50 / 0 10 0 0 5 TEMPLE, TX 52 68 46 72 49 / 5 5 0 0 5 MINERAL WELLS, TX 47 70 39 69 39 / 0 0 0 0 5 && .FWD WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 05/79
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
520 PM CST SAT NOV 30 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 345 PM CST SAT NOV 30 2013 THE MAIN FORECAST CONCERN FOR TONIGHT ARE THE CLOUDS FOR TONIGHT. THE MODELS SHOW THAT THE MID AND HIGH CLOUDS CURRENTLY OVER THE AREA WILL GRADUALLY SHIFT SOUTH AND THIN AS THEY MOVE INTO NORTHEAST IOWA AND SOUTHWEST WISCONSIN LATE TONIGHT. MEANWHILE ANOTHER AREA OF LOW CLOUDS CURRENTLY LOCATED OVER NORTHERN MINNESOTA WILL MOVE SOUTH INTO WESTERN WISCONSIN AND PORTIONS OF SOUTHEAST MINNESOTA. AS A RESULT...HAVE MANY AREAS MOSTLY CLOUDY TONIGHT. ON SUNDAY...WARM AIR ADVECTION AND WEAK TO MODERATE 285 TO 295K ISENTROPIC LIFT WILL DEVELOP ACROSS THE AREA AS A WARM FRONT MOVES NORTHEAST TOWARD THE AREA. THIS WILL KEEP SKIES MAINLY CLOUDY. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 345 PM CST SAT NOV 30 2013 FROM SUNDAY NIGHT INTO MONDAY EVENING...THE 30.00Z MODELS KEEP THE WEAK LOW PRESSURE MORE TOWARD THE DAKOTAS. THIS KEEPS THE WARM AIR ADVECTION FURTHER WEST. AS A RESULT...SHIFTED THE SLIGHT SNOW CHANCES WEST OF AN OELWEIN IOWA TO NEILLSVILLE WISCONSIN LINE. FROM LATE MONDAY NIGHT INTO WEDNESDAY NIGHT...THE MODELS CONTINUE TO STRUGGLE WITH A SHORT WAVE TROUGH EJECTING OUT AHEAD OF A DEVELOPING LONG WAVE TROUGH OVER THE WESTERN UNITED STATES. SINCE THE 30.00Z RUN...THE GFS CONTINUES TO BE THE STRONGEST AND THE FASTEST AT MOVING THIS SYSTEM THROUGH WESTERN AND NORTHERN MINNESOTA. THIS PUSHES THE ARCTIC COLD FRONT THROUGH THE AREA ON TUESDAY NIGHT. 11 OF THE 12 GFS ENSEMBLE MEMBERS SUPPORT THE OPERATIONAL GFS RUN. MEANWHILE THE ECMWF AND GEM HAS A MUCH WEAKER WAVE MOVING THROUGH WESTERN AND NORTHERN MINNESOTA. THIS KEEPS THE ARCTIC FRONT WEST OF THE FORECAST AREA UNTIL A STRONGER SHORT WAVE TROUGH EJECTS ACROSS NORTHERN AND WESTERN MINNESOTA ON WEDNESDAY NIGHT. AS A RESULT...BOTH THE TUESDAY NIGHT MINIMUM TEMPERATURE AND WEDNESDAY MAXIMUM TEMPERATURE ARE WARMER. THE ECMWF ENSEMBLE SUPPORTS THIS SLOWER SOLUTION. SINCE THE ECMWF TENDS TO DO BETTER DURING THIS TIME FRAME...IT WAS THE CONSENSUS TO TREND THE FORECAST TOWARD THE GEM AND ECMWF. WITH THERE NOT BEING TOO MUCH OF A GULF CONNECTION UNTIL THE FRONT IS OFF TO THE EAST OF THE FORECAST AREA...NOT EXPECTING TOO MUCH PRECIPITATION ALONG AND AHEAD OF THIS FRONT. SOUNDINGS SUGGEST THAT THE PRECIPITATION WILL START OFF AS SNOW OR RAIN LATE MONDAY NIGHT AND TUESDAY MORNING...AND THEN TRANSITION TO MAINLY RAIN FROM TUESDAY AFTERNOON INTO WEDNESDAY...AND THEN BACK OVER TO SNOW ON WEDNESDAY NIGHT. FROM THURSDAY NIGHT INTO FRIDAY MORNING...THE MODELS CONTINUE TO SHOW THAT A SHORT WAVE TROUGH WILL MOVE FROM THE MID MISSISSIPPI RIVER VALLEY INTO SOUTHEAST LOWER MICHIGAN. THE WARM CONVEYOR BELT IN THE GEM AND ECMWF BRINGS SOME OF THE SNOW NORTHWARD INTO EASTERN IOWA AND SOUTHERN AND EASTERN WISCONSIN. PREVIOUSLY THIS PRECIPITATION WAS WELL SOUTHEAST OF THE FORECAST AREA. DUE TO THIS SLIGHT DRIFT TO THE NORTHWEST... A SLIGHT CHANCE /15 TO 24 PERCENT/ OF SNOW WAS INTRODUCED TO THE FORECAST. FROM FRIDAY INTO SATURDAY...THE TEMPERATURE FORECAST IS RATHER TRICKY. THE ECMWF HAS 850 MB TEMPERATURES FALLING INTO THE -18C TO -20C RANGE. MEANWHILE THE GFS IS EVEN COLDER WITH 850 MB TEMPERATURES RANGING FROM -20 TO -22C. WHILE THESE TEMPERATURES ARE 2 TO 3 STANDARD DEVIATIONS BELOW NORMAL...THE HIGH TEMPERATURES AT LA CROSSE HAVE ONLY /SINCE 1892 WHEN SNOW DEPTH RECORDS BEGAN/ FALLEN BELOW 10 DEGREES ONE TIME /DECEMBER 2 1976/ WHEN THERE WAS LESS THAN AN INCH OF SNOW ON THE GROUND DURING THE FIRST TEN DAYS OF DECEMBER. SNOW IS VERY CRITICAL WHEN LOOKING AT TEMPERATURES APPROACHING RECORDS. WHEN LOOKING AT THE TEMPERATURE RECORDS FOR ALL OF DECEMBER SINCE 1893...THERE HAS ONLY BEEN 2 OCCURRENCES OF A RECORD COLD MAXIMUM /41 RECORDS/ BEING SET OR TIED WHEN THERE WAS LESS THAN AN INCH OF SNOW ON THE GROUND. MEANWHILE...THERE HAS NEVER BEEN A RECORD LOW TEMPERATURE /27 RECORDS/ SET WITH LESS THAN INCH OF SNOW ON THE GROUND. AS A RESULT...VERY LEERY OF GOING TOO COLD. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 520 PM CST SAT NOV 30 2013 COLD FRONT HAS SAGGED SOUTH OF THE TAF SITES...WITH WINDS GENERALLY LIGHT FROM THE NORTH TONIGHT THROUGH SUNDAY. CURRENTLY...BAND OF MID LEVEL CLOUDS SLIDING SOUTHWARD ACROSS THE REGION...MOSTLY 8-12 KFT. HOWEVER...FARTHER NORTH OVER NORTHERN MN/LAKE SUPERIOR THERE WAS A LARGE AREA OF LOW STRATUS...ALSO MAKING SOUTHWARD PROGRESS. MESO MODELS FAVOR KEEPING THIS CLOUD DECK TOGETHER...WITH THE RAP13 REACHING KRST/KLSE TOWARD 12Z. THE GFS/NAM NOT AS BULLISH ON BRINGING THE MVFR CLOUDS THIS FAR SOUTH. NOT CONFIDENT IN TIMING AT THIS MOMENT...OR EVEN IF THE CLOUDS WILL MAKE IT THIS FAR SOUTH...BUT WILL SIDE WITH THE RAP FOR NOW. SOUNDINGS SUGGEST THAT THERE SHOULD BE ENOUGH MIXING FOR A DIURNAL INCREASE IN CIG HEIGHT BY 18Z...AND POTENTIALLY BECOME SCT AS DRY AIR MIXES IN. TOUGH CLOUD FORECAST. TRENDS WILL HAVE TO BE MONITORED CLOSELY AND ADJUSTMENTS MADE AS NECESSARY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM....BOYNE AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1125 PM CST THU NOV 28 2013 .SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 325 PM CST THU NOV 28 2013 AT 3 PM...A LAKE INDUCED VORTICITY WAS LOCATED OVER THE APOSTLE ISLANDS IN WESTERN LAKE SUPERIOR. MEANWHILE A SURFACE LOW WAS LOCATED OVER EASTERN UPPER MICHIGAN. THIS LOW WAS PRODUCING WEAK CYCLONIC FLOW ACROSS ACROSS WISCONSIN AND EAST CENTRAL MINNESOTA. THIS CYCLONIC FLOW ALONG WITH STEEP 950-900 MB LAPSE RATES /ASSOCIATED WITH A THERMAL TROUGH LOCATED FROM NORTHERN MINNESOTA SOUTHEAST INTO EASTERN WISCONSIN/ IS HELPING MAINTAIN THESE CLOUDS. THE 28.19Z RAP HAS A VERY GOOD HANDLE ON THESE CLOUDS AND THEY SHOW THAT THEY WILL CONTINUE TO MOVE SOUTHEAST ACROSS MAINLY OUR WISCONSIN COUNTIES AND THEN QUICKLY DISSIPATES THEM BETWEEN 28.01Z AND 28.03Z AS THE FLOW STARTS TO BECOME ANTICYCLONIC AND THE 950-900 MB LAPSE RATES DECREASE. FROM LATE TONIGHT INTO FRIDAY...THE 28.12Z MODELS CONTINUE TO SHOW THAT WEAK WARM AIR ADVECTION WILL DEVELOP ABOVE 600 MB AS A WEAK SHORT WAVE TROUGH APPROACHES THE REGION FROM THE CENTRAL PLAINS. THIS WILL RESULT IN SOME MID TO HIGH CLOUDS ACROSS THE AREA. .LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 325 PM CST THU NOV 28 2013 ON FRIDAY NIGHT...THE 28.12Z MODELS CONTINUE TO SHOW THAT A STRONG SHORT WAVE TROUGH WILL MOVE SOUTHEAST ACROSS SOUTHWEST ONTARIO. MUCH OF THE PV ADVECTION ASSOCIATED WITH THIS SYSTEM STAYS WILL NORTH OF THE FORECAST AREA. THERE IS WEAK TO MODERATE 285 TO 300K ISENTROPIC LIFT ACROSS NORTHERN AND EASTERN WISCONSIN. THIS LOWERS THE CONDENSATION PRESSURE DEFICITS TO LESS 40 MB. MEANWHILE AT THE 285 AND 290K ISENTROPIC SURFACES YOU STILL NEED 100 TO 200 MB OF LIFT FOR SATURATION. AS A RESULT...IT IS NOT LOOKING PROMISING FOR ANY PRECIPITATION ACROSS TAYLOR AND NORTHERN CLARK COUNTY IN NORTH CENTRAL WISCONSIN. HOWEVER WITH THE ECMWF...GEM...AND NAM STILL INDICATING A POSSIBILITY. JUST KEPT A SLIGHT CHANCE /LESS THAN 20 PERCENT/ ACROSS THIS AREA. BUFKIT SOUNDINGS CONTINUE TO SHOW NO ICE...SO IF PRECIPITATION DOES INDEED OCCURS IT WOULD BE IN THE FORM OF FREEZING DRIZZLE. ON SATURDAY NIGHT...WEAK TO MODERATE WARM AIR ADVECTION AND STRONG 290 TO 300K ISENTROPIC LIFT DEVELOP ACROSS THE AREA AS A STRONG SHORT WAVE TROUGH MOVES ACROSS THE REGION. THE 290-300K ISENTROPIC CONDENSATION PRESSURE DEFICITS DROP TO LESS THAN 30 MB...SO WE WILL LIKELY SEE CLOUDS WITH THIS WAVE. HOWEVER...THE 285K CONDENSATION DEFICITS REMAIN IN THE 100 TO 200 MB RANGE...SO NOT EXPECTING ANY PRECIPITATION WITH THIS WAVE. FROM SUNDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO STRUGGLE WITH THE TIMING OF A SHORT WAVE TROUGH COMING OUT AHEAD OF THE DEVELOPING LONG WAVE TROUGH IN THE WESTERN UNITED STATE. BOTH THE GEM AND ECMWF BRING A WAVE AHEAD OF THIS SYSTEM. MEANWHILE THE GFS DOES NOT. AS AS RESULT...THE GEM AND ECMWF PRODUCES SOME LIGHT PRECIPITATION ACROSS THE AREA. MEANWHILE THE GFS KEEPS THE AREA DRY. SINCE THE MODELS HAVE BEEN CONSISTENT...JUST STAYED WITH THE SLIGHT CHANCES THAT THE ALL BLEND PROVIDED. FROM MONDAY NIGHT THROUGH THURSDAY...THE MODELS CONTINUE TO STRUGGLE WITH THE EVOLUTION OF A LONG WAVE TROUGH OVER THE WESTERN UNITED STATES. DUE TO THIS...THERE HAS BEEN A VARIETY OF DIFFERENT LOW PRESSURE TRACKS FROM THE NORTHERN PLAINS EAST INTO THE GREAT LAKES. THIS SYSTEM HAS THE POTENTIAL OF PRODUCING A WINTER STORM SOMEWHERE ACROSS THE REGION...BUT WHERE IS VERY UNCERTAIN...SO JUST STAYED WITH THE ALL BLEND FOR THIS TIME PERIOD. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY EVENING) ISSUED AT 1125 PM CST THU NOV 28 2013 CLOUDS HAVE FINALLY DIMINISHED...AND EXPECT SKC/SCT CONDITIONS FOR THE REST OF THE NIGHTTIME HOURS WITH LIGHT TO VRB WINDS. WINDS WILL INCREASE AND SHIFT TO THE SOUTH/SOUTHEAST A FEW HOURS AFTER DAYBREAK FRIDAY AS HIGH PRESSURE EXITS OVER THE EASTERN GREAT LAKES. SHOULD SEE SOME HIGH/MID LEVEL CLOUDS BY THIS TIME...MOSTLY IN THE 150-250 KFT RANGE. A COUPLE FORECAST CONCERNS FOR FRIDAY NIGHT. FIRST IS THE POTENTIAL FOR MVFR CIGS AT KLSE. NAM SUGGESTS LOW LEVEL MOISTURE WILL BE ON THE INCREASE IN THE EVENING...LIKELY RESULTING IN A 1500-2500 FT DECK. THE GFS IS DRIER IN THE LOW LAYERS...AND STAYS VFR. THERE WAS A LARGE SWATH OF MVFR CIGS ACROSS THE DAKOTAS THU MORNING...IN A REGION OF GOOD LOW LEVEL ISENTROPIC UPGLIDE...WHICH WILL BE SHIFTING ACROSS THE LOCAL AREA FRIDAY NIGHT. HOWEVER...THE PRESSURE GRADIENT WAS ALSO WEEK ACROSS THE DAKOTAS...WHILE LOCALLY THE PRESSURE GRADIENT WILL STAY RELATIVELY TIGHT...WITH WINDS AROUND 10 KTS. STILL...WITH INCREASING MOISTURE/TRANSPORT UNDER AN INVERSION...WOULD SEEM TO BE A DECENT SETUP FOR SOME LOW STRATUS FORMATION. CONFIDENCE SHAKY AT THE MOMENT...BUT ENOUGH TO GO ON TO ADD A MENTION FOR KLSE. THE OTHER CONCERN IS THE POTENTIAL FOR LLWS FRIDAY NIGHT. BUFKIT SOUNDINGS SUGGESTING AROUND 40 KTS BY 2 KFT FRIDAY EVENING...AND SFC WINDS DEPENDING...LLWS CRITERIA COULD BE MET. WILL LEAVE OUT OF THE FORECAST FOR NOW. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM....BOYNE AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
944 PM MST SAT NOV 30 2013 .UPDATE... ISSUED AT 940 PM MST SAT NOV 30 2013 HAVE ADJUSTED AREAS OF FOG FOR TONIGHT THROUGH SUNDAY WITH FOG MAINLY IN THE VALLEY BOTTOMS AND ALONG THE SLOPES OF THE WESTERN MOUNTAINS. SOUNDINGS OVER THE LAST 36HRS AT GJT SHOW THE STRATUS LAYER NEAR 7500FT SO HAVE ADDED FOG TO THE SLOPES DEFINED BY 7-8KFT. THE NEW NAM IS NOT RECOGNIZING THE BOUNDARY LAYER FOG SO ITS FORECAST TEMPS ARE TOO HIGH FOR THE WESTERN VALLEY SITES. THE 03Z RAP IS CAPTURING THE FOG LAYER BUT ERODES BY SUNDAY AFTERNOON. WITH WARM ADVECTION ALOFT RETURNING THEN...THE STRATUS LAYER IS EXPECTED TO PERSIST. IN THE BIGGER PICTURE...THE NAM IS STILL PRODUCING ONLY LIGHT SNOW ACCUMULATIONS MAINLY IN THE ELKHEAD AND ZIRKELS TONIGHT THROUGH SUNDAY. THE NAM12 IS PRODUCING UP TO 5 INCHES. THIS LOOKS A BIT HEAVY HANDED WITH LITTLE DYNAMICAL FORCING OR WEAK COOL ADVECTION. THE DENDRITIC CRYSTAL GROWTH REGION DOES NOT FULLY SATURATE SO OROGRAPHICS WOULD BE THE MAIN MECHANISM. MONDAY-MONDAY NIGHT...THE 00Z NAM IS MORE ROBUST AND FAST WITH THE APPROACHING TROUGH. SIGNIFICANT SNOW STARTS ACROSS THE NORTH MONDAY NIGHT AND SPREADS ACROSS THE CWA ON TUESDAY. WILL EVALUATE OVERNIGHT FOR A POTENTIAL WATCH. && .SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT) ISSUED AT 427 PM MST SAT NOV 30 2013 INVERSIONS WHICH FORMED IN THE WAKE OF LAST WEEK/S STORM REMAINED IN PLACE TODAY. AS A RESULT...LOW CLOUDS AND FOG CONTINUED TO IMPACT VALLEYS BELOW 6500 FEET ASL AND ADJACENT MOUNTAINS TO BETWEEN 8000 AND 8500 FEET. DAYTIME WARMING ENHANCED BY CLEAR SKIES ON THE EDGE OF THE STRATUS FIELD WILL CONTINUE TO ERODE THE STRATUS THROUGH THE AFTERNOON...BUT EXPECT CLOUDS WILL AGAIN SPREAD UPVALLEY WITH FOG REFORMING IN RESPONSE TO COOLING TEMPERATURES OVERNIGHT. SOME QUESTION AS TO WHETHER THE APPROACHING SHORTWAVE TROUGH IN THE NORTHWESTERLIES WILL ALLOW FOR MIXING OF LOWER LEVELS LATE TONIGHT. WAA AHEAD OF THIS FEATURE SUGGESTS OTHERWISE AND SURFACE PRESSURE GRADIENT WEAK AT BEST. CONSEQUENTLY...WILL LEAVE LOW CLOUDS AND CONTINUE WITH FORECAST FOR FOG. FOR THE NORTHERN MOUNTAINS...LIFT AND MOISTURE ASSOCIATED WITH THE SHORTWAVE MAY BEGIN TO GENERATE SOME LIGHT SNOW AFTER MIDNIGHT. SNOW WILL INCREASE OVER THE ELKHEAD AND PARK RANGES EARLY SUNDAY AS THE SHORTWAVE SWEEPS OVER THE AREA. THERE WILL BE A BRIEF PERIOD OF DYNAMIC LIFT WITH THE WAVES PASSAGE SUNDAY MORNING. THEREAFTER...FROM SUNDAY AFTERNOON THROUGH SUNDAY NIGHT... OROGRAPHIC LIFT WILL BECOME THE DOMINANT MECHANISM FOR SNOW AS STRONG WEST TO WEST-NORTHWEST WINDS FROM 20 TO 30 MPH BUFFET THE AREA. THE 12Z/SAT BUFR SOUNDING FOR KHDN INDICATED THAT A SATURATED DENDRITIC GROWTH REGION WILL ENHANCE SNOWFALL SUNDAY MORNING...BUT QUICKLY DRIES AND RISES WITH TROUGH PASSAGE BY MIDDAY AS TEMPERATURE ADVECTION SHIFTS FROM WEAKLY COLD AIR ADVECTIVE...TO NEUTRAL SUNDAY AFTERNOON...THEN BECOMES WARM AIR ADVECTIVE SUNDAY EVENING. THOUGH WAA WILL LIMIT ACCUMULATIONS BELIEVE ELKHEADS AND SOME OF THE PARK RANGE COULD SEE AMOUNTS CLOSER TO NAM GUIDANCE OF 3 TO 6 INCHES SUNDAY AND SUNDAY NIGHT... BUT MAINLY OVER HIGHER EXPOSED PEAKS. IT/S DOUBTFUL THAT THIS ACTIVITY WILL HAVE MUCH AFFECT ON THE VALLEY INVERSIONS DISCUSSED PREVIOUSLY AND THEREFORE WILL CONTINUE TO FORECAST LOW CLOUDS AND FOG FOR THOSE AREAS. MEANWHILE...THE SOUTHERN MOUNTAINS MAY SEE SOME MID AND HIGH CLOUDS BUT ARE UNLIKELY TO GET SNOWFALL. AS FOR TEMPERATURES...SEE NO REASON TO STRAY FROM PERSISTENCE FORECAST THROUGH THE NEXT THREE PERIODS. THE ONLY EXCEPTION IS ACROSS THE NORTH WHERE INCREASED LOW AND MID CLOUDS SHOULD BRING SLIGHTLY WARMER LOWS SUNDAY NIGHT. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 427 PM MST SAT NOV 30 2013 OROGRAPHIC SNOWFALL ALONG THE NORTHERN DIVIDE WILL TAPER OFF ON MONDAY AS THE FLOW TRANSITIONS FROM NORTHWEST EARLY IN THE DAY TO WESTERLY BY EVENING. THIS SHIFT IN THE FLOW IS THE RESULT OF THE NEXT STORM SYSTEM DROPPING INTO THE PACIFIC NORTHWEST THROUGHOUT THE DAY. AS THIS HAPPENS THE GRADIENT WILL TIGHTEN...MAINLY OVER THE NORTH. OTHER THAN BREEZES OVER THE HIGHER TERRAIN AND NORTH...AND A FEW LINGERING SNOW SHOWERS OVER THE NORTHERN DIVIDE...MONDAY WILL GENERALLY BE A QUIET DAY. THEN THE BIG CHANGE IN CONDITIONS WILL BEGIN TO TAKE PLACE ON TUESDAY AS THE NORTHWEST UPPER LOW PRESSURE SYSTEM AND ITS ASSOCIATED SURFACE COLD FRONT APPROACH FROM THE NORTHWEST. THIS MUCH ADVERTISED STORM SYSTEM IS STILL ON TRACK TO BRING SIGNIFICANT WEATHER TO THE FORECAST AREA BEGINNING LATE TUE THROUGH WED...WITH COLD TEMPERATURES AND THE POTENTIAL FOR CONTINUED UNSETTLED CONDITIONS THROUGH THE END OF THE LONG TERM PERIOD. THE FLOW BECOMES SOUTHWEST MON NIGHT INTO TUE AND STRENGTHENS AS THE UPPER LOW TRACKS INTO ID. IN ADDITION...THE STRONG SURFACE COLD FRONT WILL REACH OUR NORTH/NORTHWEST EDGE LATE IN THE AFTERNOON TO THE EVENING...THEN PROCEED SOUTH/SOUTHEAST OVERNIGHT. IN THE PRE-FRONTAL ENVIRONMENT SOUTHWEST WINDS WILL BECOME STRONG ACROSS THE MOUNTAINS EARLY IN THE DAY...THEN WILL MIX INTO THE VALLEYS BY THE AFTERNOON. THE GFS IS QUITE A BIT FASTER THAN THE NAM12 AND ECMWF WITH THE TIMING OF THIS FRONT. IT BRINGS THE FRONT INTO NORTHWEST CO/NORTHEAST UT IN THE MORNING...WHERE IT STALLS NORTH OF THE TAVAPUTS/FLATTOPS THROUGH THE AFTERNOON/EVENING. WHILE I MOSTLY DISCOUNTED THE GFS TIMING DUE TO LACK OF AGREEMENT AND CONTINUITY...IF IT WERE TO VERIFY IT COULD RESULT IN SIGNIFICANT SNOW OVER THE NORTH THROUGH TUE. GENERALLY FOLLOWING THE NAM AND ECMWF...POPS GRADUALLY TREND UPWARDS THROUGH TUE OVER THE NORTH...THEN INCREASE AND SPREAD SOUTH OVERNIGHT. WHILE THE UPPER LOW CENTER IS PROGGED REMAIN TO OUR NORTH...AT LEAST A COUPLE OF SHORTWAVES WILL SWING AROUND ITS BASE AND ACROSS OUR FORECAST AREA. WED PROMISES TO BE THE MOST ACTIVE DAY AS THE FIRST SHORTWAVE AND AN ASSOCIATED 120KT JET PASS OVERHEAD BRINGING GOOD DYNAMICS AND UPPER SUPPORT TO A SATURATED AIR MASS. PRECIPITATION WILL MOSTLY BE SNOW IN THE WAKE OF THE STRONG SURFACE FRONT AND BY WED EVENING ALL AREAS WILL SEE SNOW IN THE COLD ADVECTION BEHIND THE SHORTWAVE/COLD FRONT. ANOTHER SHORTWAVE WILL SWING AROUND THE LOW THU/THU NIGHT BRINGING EVEN COLDER AIR OVER THE REGION...-32C/500MB AND -20C/700MB. THIS COLD AIR MASS WILL JUST NOT BE ABLE TO HOLD MUCH MOISTURE...AND MODELS INDICATE A MARKED DOWNTURN IN POPS. HOWEVER MODELS OFTEN DRY THINGS OUT TOO FAST. THEREFORE KEPT AT LEAST CHANCE/MOUNTAINS...SLIGHT CHANCE/VALLEYS THROUGH THE DAY ON THU. THEN POPS DIMINISH THROUGH FRI AND SAT. HOWEVER COLD CONDITIONS AND GENERAL TROUGHINESS WILL PERSIST OVER THE REGION THROUGH THE END OF THE WEEK. SO UNSETTLED CONDITIONS ARE POSSIBLE THROUGH SAT. FRI AND SAT MORNINGS ARE PROMISING TO BE THE COLDEST SO FAR THIS SEASON WITH TEMPS AT MANY LOCATIONS DROPPING INTO THE SINGLE DIGITS OR BELOW ZERO...WITH LOWER TEENS ELSEWHERE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING) ISSUED AT 940 PM MST SAT NOV 30 2013 STRATUS AND LIGHT FOG ARE EXPECTED TO CONTINUE OVERNIGHT...EXPANDING EASTWARD OVERNIGHT TO INCLUDE CEZ-DRO. THE ONLY EXCEPTION TO THIS RULE WILL BE ACROSS THE NORTH...WHERE AN UPPER LEVEL DISTURBANCE MAY WEAKEN INVERSIONS CAUSING CLOUDS TO LIFT WHILE FOG DECREASES IN COVERAGE AND INTENSITY. MVFR CIGS WILL LINGER IN THE LOWER VALLEYS BEFORE EXPANDING EAST WHILE PATCHY FOG DEVELOPS. FOG WILL SPREAD...BECOMING LOCALLY DENSE LATE TONIGHT AND INTO SUNDAY MORNING RESULTING IN AREAS OF IFR VSBY AND CIGS. AREAS EAST WILL HAVE VFR CONDITIONS THROUGHOUT THE NEXT 24 HOURS. THE ONLY EXCEPTION BEING THE NORTHERN COLORADO MOUNTAINS WHERE THE DISTURBANCE MENTIONED PREVIOUSLY WILL BRING NUMEROUS SNOW SHOWERS RESULTING IN MOUNTAIN OBSCURATIONS OF THE ELKHEAD AND PARK RANGES ON SUNDAY. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...JOE SHORT TERM...NL LONG TERM...EH AVIATION...NL/JOE
AREA FORECAST DISCUSSION
NWS MIAMI FL
319 AM EST SUN DEC 1 2013 DISCUSSION... HIGH PRESSURE TO THE NORTH CONTINUES TO BRING NORTHEASTERLY FLOW TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN TO WEAKEN TODAY, ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS STILL A FEW SHOWERS OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE NOT IMPACTING THE CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE FORECAST. THE HRRR DOES SHOW SOME ISOLATED SHOWERS OVER THE ATLANTIC COAST METRO AREAS THIS AFTERNOON, SO BROUGHT SLIGHT CHANCE POPS SOMEWHAT MORE WEST. MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING. EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS, COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER TODAY. AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE, ESPECIALLY IN THE OVERNIGHT HOURS. AVIATION... MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME. ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE DRAINAGE FLOW BEGINNING. MARINE... HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 80 62 78 61 / 20 10 10 - FORT LAUDERDALE 80 64 78 63 / 20 10 10 - MIAMI 80 64 79 63 / 20 10 10 - NAPLES 78 63 76 62 / - - 10 - && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...13/SI AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS MIAMI FL
315 AM EST SUN DEC 1 2013 .DISCUSSION... HIGH PRESSURE TO THE NORTH CONTINUES TO BRING EAST TO NORTHEASTERLY FLOW TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN TO WEAKEN TODAY, ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS STILL A FEW SHOWERS OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE NOT IMPACTING THE CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE FORECAST. THE HRRR DOES SHOW SOME ISOLATED SHOWERS OVER THE ATLANTIC COAST METRO AREAS THIS AFTERNOON, SO BROUGHT SLIGHT CHANCE POPS SOMEWHAT MORE WEST. MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING. EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS, COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER TODAY. AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE, ESPECIALLY IN THE OVERNIGHT HOURS. && .AVIATION... MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME. ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE DRAINAGE FLOW BEGINNING. && .MARINE... HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 80 62 78 61 / 20 10 10 - FORT LAUDERDALE 80 64 78 63 / 20 10 10 - MIAMI 80 64 79 63 / 20 10 10 - NAPLES 78 63 76 62 / - - 10 - && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...13/SI AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
252 AM CST SUN DEC 1 2013 .DISCUSSION... 252 PM CST SYNOPSIS...MORE SEASONAL TEMPERATURES WILL BE WITH US THROUGH EARLY NEXT WEEK...WITH TEMPS PEAKING MID WEEK. THEN TEMPS QUICKLY FALL TO WELL BELOW NORMAL BY NEXT WEEKEND. THERE A FEW SLIGHT CHANCES OF PRECIP EARLY NEXT WEEK WITH A MUCH BETTER CHANCE FOR PRECIP MID WEEK. THE MID WEEK SYSTEM WILL BRING MOSTLY RAIN WITH A CHANCE OF WINTRY PRECIP LATE NEXT WEEK. REST OF TODAY THROUGH SUNDAY... WEAK LOW PRESSURE IS OVER LAKE SUPERIOR AND NORTHERN WI WITH ITS COLD FRONT STRETCHING FROM MEDFORD WI THROUGH MASON CITY IA. THE LOW WILL CONTINUE EASTWARD AND DISSIPATE OVER THE EASTERN GREAT LAKES SUNDAY NIGHT. WE HAVE MIXED MUCH MORE THAN WE WERE EXPECTING TODAY...RESULTING IN HIGH TEMPS IN THE LOWER 50S. NOT BAD FOR LATE NOVEMBER! AS SUCH RAISED LOW TEMPS BY A COUPLE DEGREES TONIGHT. CLOUDS WILL ALSO BE INCREASING THIS EVENING AND OVERNIGHT LIMITING COOLING. AN UPPER LEVEL SHORTWAVE PASSES OVERHEAD TOMORROW MORNING WITH NO PRECIP EXPECTED. CAA ALOFT AND WEAK SURFACE FLOW LEAD ME TO BELIEVE WE WILL BE A BIT COOLER TOMORROW WITH HIGHS AROUND 40. MONDAY AND TUESDAY... ANOTHER SLIGHTLY DEEPER UPPER LEVEL SHORTWAVE ARRIVES MONDAY. THIS TROUGH IS ALSO FURTHER SOUTH MOVING RIGHT OVER NORTHERN IL...WHICH MAY PROVIDE JUST ENOUGH FORCING FOR A LITTLE LIGHT PRECIP. TEMPS WILL BE ON THE RISE THROUGH THE MORNING SO WENT WITH LIGHT SNOW AT FIRST TURNING OVER TO RAIN BY MONDAY AFTERNOON. THE PRECIP WILL TRAVEL EAST WITH THE SHORTWAVE THROUGH THE DAY. HIGH TEMPS ON MONDAY WILL ONCE AGAIN BE AROUND 40. AN UPPER LEVEL VORT STREAMER PASSES JUST TO THE NORTH LATE MONDAY NIGHT WHICH MAY PRODUCE A LITTLE LIGHT SNOW OVER NORTH CENTRAL IL. MAY SEE A LITTLE MORE PRECIP COVERAGE TUESDAY MORNING WITH PRECIP TURNING OVER TO RAIN AS TEMPS WARM. THE FORCING THEN LIFTS OFF TO THE NE SO KEPT A SLIGHT CHANCE OF PRECIP OVER NORTH CENTRAL IL TUESDAY AFTERNOON WITH THE MAJORITY OF PRECIP STAYING NORTH OF OUR REGION CLOSER TO THE VORT STREAMER. A STATIONARY FRONT THEN STRETCHES OVER NORTHERN IL TUESDAY NIGHT SO KEPT A SLIGHT CHANCE TO CHANCE OF RAIN GOING. WAA ALOFT WILL KEEP TUESDAY NIGHT TEMPS ABOVE FREEZING. WEDNESDAY THROUGH FRIDAY... THE UPPER LEVEL RIDGE SHIFTS TO THE EAST WITH SOUTHWEST FLOW SETTING UP THROUGH LATE FRIDAY. THE UPPER LEVEL TROUGH AXIS PASSES OVERHEAD SATURDAY. LONG DISTANCE GUIDANCE AGREES ON THE OVERALL PATTERN...BUT THE GFS AND ECMWF DIFFER GREATLY ON WHEN THESE FEATURES WILL IMPACT THE REGION. WENT WITH THE MORE STEADY ECMWF IN THE LONG TERM AS THE GFS LOOKS MUCH TOO FAST. A SURFACE LOW MOVES OVER THE CENTRAL PLAINS LATE TUESDAY NIGHT INTO WEDNESDAY WITH WAA IMPACTING THE REGION TUESDAY NIGHT THROUGH WEDNESDAY EVENING. WITH ALL OF THE WAA RAISED TEMPS TUESDAY NIGHT AND WEDNESDAY...AND HONESTLY...STILL THINK TEMPS ARE TOO LOW. COULD EASILY SEE AT LEAST LOW 50S ON WEDNESDAY. RAIN ARRIVES BEHIND THE WARM FRONT WEDNESDAY AFTERNOON WITH GUIDANCE BACKING OFF A LITTLE WITH QPF...TO AROUND 0.1 INCHES. THE LOWS COLD FRONT SWINGS THROUGH WED NIGHT/THURSDAY WITH TEMPS CRASHING BEHIND IT. COULD EASILY SEE A 10+ DEGREE DIFFERENCE IN HIGH TEMPS WEDNESDAY AND THURSDAY. PRECIP MAY LINGER A BIT BEHIND THE COLD FRONT...MEANING WINTRY PRECIP IS POSSIBLE. GUIDANCE INDICATES PRECIP WILL ALSO FORM AHEAD OF THE UPPER LEVEL TROUGH AXIS...RESULTING IN RAIN/SNOW THURSDAY BECOMING ALL SNOW THURSDAY NIGHT THROUGH LATE FRIDAY. ARCTIC AIR MOVES IN WITH THE TROUGH AXIS RESULTING IN HIGH TEMPS IN THE 20S LATE NEXT WEEK. MAY EVEN SEE HIGH TEMPS IN THE TEENS ON SATURDAY. CONFIDENCE IS HIGH THAT THE SYSTEM WILL IMPACT THE REGION MID NEXT WEEK...PRECIP WILL BE MOSTLY RAIN...AND IN TEMP TRENDS. MEDIUM CONFIDENCE IN HOW LONG PRECIP WILL LINGER. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * MVFR CIGS LIKELY DEVELOPING SUNDAY MORNING AND LINGERING THROUGH THE DAY. RATZER //DISCUSSION...UPDATED 06Z... WEAK LOW PRESSURE WAS OVER NORTHERN LOWER MICHIGAN LATE THIS EVENING...WITH A WEAK/DIFFUSE COLD FRONT TRAILING ACROSS SOUTHERN WI. THIS FRONT WILL CONTINUE TO MOVE SOUTHEAST ACROSS THE TERMINALS DURING THE EARLY MORNING HOURS...WITH WINDS SHIFTING FROM LIGHT WEST-SOUTHWEST TO NORTHERLY. WINDS WILL BECOME MORE NORTH- NORTHEAST LATER IN THE MORNING...THOUGH WITH SPEEDS GENERALLY LESS THAN 10 KT. LARGE AREA OF MVFR STRATUS TRAILING THE FRONT ACROSS NORTHERN WI/MI...THOUGH MAKING SLOW SOUTHWARD PROGRESS PER GOES IR SATELLITE IMAGERY. HIGH-RES RAPID REFRESH ENSEMBLE GUIDANCE INDICATES MVFR CIGS ARRIVE AT ORD/MDW DURING THE LATE MORNING HOURS AS WINDS TURN A BIT MORE NORTH-NORTHEAST. LITTLE CHANGE IN CONDITIONS THEN ANTICIPATED THROUGH THE DAY/EARLY EVENING. RATZER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM-HIGH CONFIDENCE IN MVFR DEVELOPING SUNDAY BUT LOW CONFIDENCE IN TIMING. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...MVFR PROBABLE. CHANCE OF -SN. MONDAY NIGHT INTO TUESDAY...MVFR CIGS POSSIBLE. WEDNESDAY...MVFR CIGS LIKELY WITH IFR POSSIBLE. CHANCE OF -RA. THURSDAY AND FRIDAY...MVFR CIGS LIKELY WITH IFR POSSIBLE. CHANCE OF -SN IZZI && .MARINE... 252 AM CST MAIN MARINE FORECAST CONCERNS FOCUS ON DEVELOPMENT OF STRONG LOW PRESSURE OVER THE PLAINS MONDAY-TUESDAY...WHICH THEN IS EXPECTED TO LIFT NORTHEAST ACROSS THE NORTHERN LAKES ON WEDNESDAY. THERE CONTINUES TO BE SOME SPREAD IN MODEL SOLUTIONS WITH THE DEPTH... TRACK AND TIMING OF THE LOW. WEAK LOW PRESSURE WAS OVER LOWER MICHIGAN STATE EARLY THIS MORNING...WITH A COLD FRONT TRAILING ACROSS SOUTHERN LAKE MICHIGAN. THE LOW WILL CONTINUE TO TRACK EAST ACROSS THE EASTERN LAKES THROUGH THIS EVENING...WITH THE FRONT PUSHING SOUTHEAST OF LAKE MICHIGAN LATER THIS MORNING. WEAK HIGH PRESSURE RIDGING WILL THEN MOVE ACROSS THE WESTERN LAKES LATER TODAY/TONIGHT...DRIFTING SLOWLY OFF TO THE EAST ON MONDAY. WITH A RELATIVELY WEAK PUSH TO THE FRONT TODAY... WINDS WILL SHIFT TO THE NORTH AT GENERALLY LESS THAN 15 KT. FORECAST MODELS CONTINUE TO DEPICT AN AREA OF LOW PRESSURE DEVELOPING ACROSS THE HIGH PLAINS BY EARLY MONDAY...WHICH THEN DEEPENS ACROSS THE CENTRAL PLAINS MONDAY NIGHT. VARIOUS MODEL SOLUTIONS CONTINUE TO SHOW DIFFERENCES WITH THE EVOLUTION OF THIS LOW THROUGH MID-WEEK...THOUGH THERE IS SOME CONSENSUS IN LIFTING THE LOW NORTHEAST ACROSS THE NORTHERN GREAT LAKES WEDNESDAY. GENERALLY HAVE CONTINUED TO FOLLOW THE SLOWER SOLUTIONS OF THE ECMWF/GEM/UKMET WITH THIS SYSTEM...THOUGH WILL HAVE TO SEE SOME OF THE DIFFERENCES IRONED OUT BEFORE CONFIDENCE INCREASES IN DETAILS OF STRENGTH/TRACK AND TIMING. IT DOES APPEAR THAT THE POTENTIAL EXISTS FOR SOUTHEAST 30-35 KT WINDS AHEAD OF THE LOW LATE TUESDAY INTO WEDNESDAY...AND WEST GALES LATER WEDNESDAY INTO THURSDAY WITH THE PASSAGE OF THIS STORM. STILL 3-4 DAYS OUT SO WILL NOT HAVE ANY HEADLINES...THOUGH WILL MENTION POSSIBLE GALES IN FORECAST FOR THIS PERIOD. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion National Weather Service Lincoln IL 248 AM CST Sun Dec 1 2013 .DISCUSSION... ISSUED 248 AM CST Sun Dec 1 2013 Main forecast challenge focuses on departing storm system for the middle and end of the week...and whether or not it will produce any wintry precipitation across central Illinois. SHORT TERM...Today through Tuesday Weak cold front currently across northern Illinois will sink southward today, eventually becoming stationary along the Ohio River by evening. Front will be accompanied by little in the way of sensible weather other than a shift in the wind. Low-level moisture seen on IR/fog satellite across southeast Missouri/far southern Illinois is progged by HRRR to remain mostly south of I-70 today, while patchy mid-level clouds over Iowa into far northern Illinois stay mostly north of the area. End result will be mostly sunny skies until later this afternoon when clouds begin to approach from the northwest. High temperatures will be bit cooler behind the cold front, ranging from the middle 40s far northwest around Galesburg to the lower 50s south of I-70. Boundary will remain in place along the Ohio River through Monday, before lifting back northward in response to rising upper-level heights Monday night into Tuesday. Models continue to show a subtle short-wave rippling eastward out of the Plains late Sunday night into Monday that could interact with the front to produce scattered light showers. Forecast soundings remain dry at low-levels: however, think forcing will be strong enough to mention a slight chance for showers on Monday. As front lifts northward, rain chances will shift into the southern Great Lakes on Tuesday. Brisk southerly winds south of the departing warm front will bring much warmer air into the region, with Tuesday afternoon highs reaching the lower to middle 50s. LONG TERM...Wednesday through Saturday Forecast becomes more challenging in the extended, as upper low currently over northwest British Columbia drops southward and carves a deep trough across the western CONUS by the middle of the week. Downstream ridging will place the Midwest/Great Lakes in a broad southwesterly flow pattern, leading to increased precip chances Wednesday into Thursday. Models have been struggling with the evolution of a surface low pressure system and its associated cold front for the past several runs: however, the 00z DEC 1 run seems to be coming into better agreement. While GFS remains a fast outlier, the latest ECMWF has sped up the front quite a bit. Following an ECMWF/GEM consensus yields FROPA across central Illinois on Wednesday followed by sharply colder conditions for the end of the week. Main question will be how much precip will hold back in the colder airmass Thursday and possibly Friday. Previous runs of the ECMWF had featured quite a bit of wintry precip Thursday night into Friday as a secondary wave of low pressure tracked along the departing front. While it still shows the potential for wintry precip, it has backed off/shifted E/SE with its latest solution. GEM seems to be the most consistent model over the past couple of days, so have trended toward its solution. With cold front passing on Wednesday, will mention a chance for showers. After FROPA, precip will largely shut off Wednesday night, before a wave of low pressure tracking from the lower Mississippi River Valley into the Ohio River Valley brings a renewed round of precip primarily across the eastern half of the KILX CWA on Thursday/Thursday night. Have focused highest POPs along/east of I-57 for both Thursday and Thursday night, tapering down to just slight chances further west along/west of the Illinois River. Precip type during the day Thursday will be rain across the east, with a rain/snow mix along I-55 and mostly light snow in the Illinois River Valley. As deeper layer of cold air arrives, precip will change to light snow across the board Thursday night, with a light accumulation possible. After that, will hold on to low chance POPs for snow across the far E/SE on Friday, although if trends continue, these may need to be dropped entirely. Main weather story for the end of the week will be the much colder conditions. Highs by Friday and Saturday will only be in the 20s, with overnight lows in the single digits and teens. Barnes && .AVIATION... ISSUED 1118 PM CST Sat Nov 30 2013 VFR conditions will prevail at all sites next 24hrs. Becoming increasing obvious that light fog will not be developing overnight. However, still thinking there is some lower level moisture there and that some light fog still possible, but only as a TEMPO group in the early morning hours from about 10-13z. Also vis will not drop that much so TEMPO vis will be MVFR at 3-5SM. Besides that, skies will be clear overnight and through tomorrow. Then mid clouds around 12kft will advect into the area for the evening hours. A weak front will move through the area overnight, which should have winds switching to southwest and then west. However, speeds are so light that variable direction is best overnight. Then winds should be north to northwest after FROPA and then become northeast during the evening hours. Auten && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
359 AM EST SUN DEC 1 2013 .SYNOPSIS... LOW PRESSURE IS EXPECTED TO CROSS THE STATE TODAY AND REDEVELOP IN THE GULF OF MAINE TONIGHT, PASSING WELL E OF THE REGION ON MONDAY. ANOTHER LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE MIDDLE PART OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... CHALLENGE TODAY INTO TONIGHT WILL BE THE EXTENT OF THE WARM AIR AND SNOWFALL AMOUNTS. THE FIRST BATCH OF SNOW ASSOCIATED W/WAA THIS MORNING WAS NEAR THE MAINE-NEW BRUNSWICK BORDER PER RADAR LOOP. IR SATL IMAGERY SHOWED BEST ENHANCEMENT LINING UP WELL W/HIGHER RADAR RETURNS IN THIS REGION. ADJUSTMENTS WERE MADE TO THE SNOW IN AREAL COVERAGE SHOWING 60-80% OVER THE EASTERN AREAS THIS MORNING. THIS MATCHES UP WELL W/THE LATEST NAM12 AND RAP MODELS. AROUND AN INCH OF SNOW CAN BE EXPECTED W/THIS FIRST BURST. WEAK LOW PRES MOVING ACROSS THE EASTERN GREAT LAKES IS FCST TO MOVE ACROSS SOUTHERN NEW ENGLAND THIS AFTERNOON AND THEN INTO THE GULF OF MAINE. THE CONCERN IS WHERE TO DRAW THE RAIN/SNOW LINE AS WAA MAKES ITS WAY TO THE BLYR. TEMPERATURES ARE FCST TO REACH INTO THE UPPER 20S TO AROUND 30 ACROSS THE NORTHERN 1/2 OF THE CWA WHILE LOW TO MID 30S ARE EXPECTED FOR CENTRAL AND DOWNEAST AREAS. AN INVERTED TROF EXTENDING FROM THE LOW COMBINED W/SOME FRONTOGENETICAL FORCING AT 1000-700MB WILL LEAD TO A REFORMATION OF PRECIP AND AN ENHANCEMENT OF THE PRECIP. USING THE BUFKIT PROFILES AND SOUNDINGS, THINKING HERE IS THAT SNOW WILL REDEVELOP ACROSS PORTION OF NORTHEAST MAINE W/THE HEAVIEST AXIS ACROSS THE HOULTON AND DANFORTH REGION W/LESS SNOW NORTH AND WEST. S OF OF THE HOULTON-DANFORTH LINE, TEMPERATURES WILL WARM INTO THE MID 30S TO ALLOW FOR SNOW TO MIX WITH AND CHANGEOVER TO RAIN. THIS IN TURN WILL CUT DOWN ON SNOWFALL LATER THIS AFTERNOON INTO TONIGHT. DECISION WAS TO GO AHEAD AND ADD NORTHERN PENOBSCOT AND SE AROOSTOOK COUNTY IN THE WINTER WEATHER ADVISORY THROUGH MONDAY MORNING DUE TO ENHANCED FRONTOGENTICAL FORCING LEADING TO HEAVY SNOW BURSTS. LATEST SNOW TOTAL MAP SHOWS A GENERAL 4-8 INCHES IN THE ADVISORY AREA W/1-4 INCHES N AND W. THE COAST AND EXTREME EASTERN WASHINGTON COUNTY FROM MEDDYBEMPS TO EASTPORT WILL SEE 0.30 TO 0.70 INCHES OF RAINFALL AFTER SOME INITIAL SNOWFALL. SNOW WILL CONTINUE INTO TONIGHT ACROSS THE NORTHEASTERN SECTION OF MAINE INCLUDING CARIBOU-PRESQUE ISLE DOWN THROUGH DANFORTH. WEST OF THIS AREA, LITTLE OR NO SNOW AND RAIN/SNOW S OF THIS AREA W/RAIN FOR THE COAST AS THE WARM AIR IS FCST TO STAY IN. TEMPERATURES WILL DROP BACK INTO THE UPPER TEENS AND LOWER 20S NORTH AND WEST AND MID TO UPPER 20S FOR CENTRAL AREAS. LOW 30S FOR THE DOWNEAST REGION INCLUDING THE COAST. && .SHORT TERM /MONDAY THROUGH TUESDAY/... SNOW WILL CONTINUE TO WIND DOWN EARLY MONDAY AS THE INVERTED TROF EXTENDING FROM THE CANADIAN MARITIMES THROUGH DOWNEAST MAINE MOVES OFF TO THE NORTHEAST. THERE MAY STILL BE SOME LINGERING LIGHT SNOW OR SNOW SHOWERS PARTICULARLY ACROSS EASTERN AREAS OTHERWISE EXPECT MOSTLY CLOUDY SKIES ACROSS THE REGION. MONDAY NIGHT WILL BE MOSTLY CLOUDY BUT DRY AS WEAK HIGH PRESSURE RIDGES DOWN FROM THE NORTH. ATTENTION THEN TURNS TO ANOTHER LOW PRESSURE SYSTEM THAT WILL BE MOVING NORTHEAST ACROSS THE WESTERN ATLANTIC. THIS SYSTEM MAY BRINGS SOME PRECIPITATION TO THE REGION LATER TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... MODELS SEEM TO BE COMING INTO BETTER AGREEMENT FOR THE NEXT SYSTEM TUESDAY NIGHT AND WEDNESDAY. STILL SOME MODEL DIFFERENCES BUT THE CONSENSUS SOLUTION IS FOR THE LOW TO TRACK FAR ENOUGH EAST THAT ANY IMPACTS IN OUR REGION WOULD BE ACROSS DOWNEAST/EASTERN MAINE. A WEAK BOUNDARY WILL CROSS THE REGION BY LATE WEEK WITH SOME SNOW/RAIN SHOWERS POSSIBLE. AGAIN...WILL STICK CLOSE TO THE SUPERBLEND. HIGH PRESSURE WILL BUILD EAST TOWARD THE REGION BY SATURDAY. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... NEAR TERM: MVFR W/PERIODS OF VFR THIS MORNING DROPPING TO MVFR AND EVEN IFR LATER THIS MORNING ON INTO TONIGHT. SNOW ACROSS THE NORTHERN TERMINALS W/SNOW TO RAIN FOR KBGR TO KBHB. SHORT TERM: MVFR CONDS ARE POSSIBLE EARLY MONDAY THEN VFR CONDS EXPECTED MONDAY NIGHT INTO TUESDAY. MVFR CONDS ARE POSSIBLE IN SOME LIGHT PRECIP LATE TUESDAY AND INTO EARLY WEDNESDAY. VFR ON THURSDAY. && .MARINE... NEAR TERM: DECIDED TO GO W/A SCA THROUGH LATE MORNING. WINDS GUSTING TO 25 KTS AS LLVL JET OF 30 KT MOVES ACROSS THE WATERS. THE GFS AND NAM AS WELL AS THE LATEST RAP MODEL PICK UP ON THIS FEATURE. WINDS ARE FCST TO DROP OFF THIS AFTERNOON AS THE LLVL JET SHIFTS TO THE E. SEAS ARE AT 5FT AND COULD TIP 6 FT ESPECIALLY AT 44027(JONESPORT) THIS MORNING. SEAS WILL GRADUALLY SUBSIDE TONIGHT BELOW 4 FT. SHORT TERM: WINDS/SEAS WILL BE BELOW SCA LEVELS MON AND MON NIGHT. WIND/SEAS MAY INCREASE TO SCA LEVELS TUE/TUE NIGHT. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ005-006- 011-016-017-032. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR ANZ050>052. && $$ NEAR TERM...HEWITT SHORT TERM...DUDA LONG TERM...DUDA AVIATION...HEWITT/DUDA MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1247 AM EST SUN DEC 1 2013 .SYNOPSIS... LOW PRESSURE IS EXPECTED TO CROSS THE STATE ON SUNDAY. ANOTHER LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE MIDDLE PART OF NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... UPDATE...RAMPED UP SNOWFALL CHANCES TO 90% OR MORE ACROSS THE NORTHERN 1/2 OF THE CWA AS THE LATEST RADAR LOOPS SHOWED A DECENT SWATH OF SNOW MOVING ACROSS THE REGION. DECIDED OF 40-60% FOR SNOW FROM CENTRAL AND DOWNEAST AREAS. LIGHT ACCUMULATIONS ARE EXPECTED THROUGH THE EARLY MORNING. THE LATEST HRRR AND RAP WERE DOING WELL W/THE PLACEMENT OF THE SNOW. ADJUSTED THE HRLY TEMPERATURES TO MATCH THE LATEST CONDITIONS. SOME COOLING STILL IS EXPECTED ACROSS THE FAR NORTH AND WEST AS THIS FIRST BATCH OF SNOW PUSHES E. WINTER WEATHER ADVISORIES REMAIN IN PLACE ATTM FOR INTERIOR DOWNEAST MAINE W/SNOW TOTALS OF 3 TO 6 INCHES EXPECTED. SOME OF THE LATEST NUMERICAL GUIDANCE IS SHOWING MORE SNOW IN EASTERN MAINE THROUGH SUNDAY NIGHT. THIS WILL NEED TO RE-VISITED DURING THE MORNING PACKAGE. WEAK LOW PRESSURE WILL SLIDE EASTWARD ACROSS THE GREAT LAKES INTO SUNDAY. AS SUCH, EXPECT LIGHT SNOW TO DEVELOP OVER THE REGION FROM NORTHWEST TO SOUTHEAST TONIGHT AND CONTINUE THROUGH THE DAY ON SUNDAY. MODEL GUIDANCE CONTINUES TO INDICATE THAT A BAND OF MODERATE TO HEAVY SNOW WILL DEVELOP LATER SUNDAY INTO SUNDAY NIGHT IN ASSOCIATION WITH AN INVERTED TROUGH THAT WILL SET UP SOMEWHERE ALONG THE COAST. WHILE THE NAM HAS COME MORE INTO LINE OVER THE PAST FEW RUNS, IT CONTINUES TO BE A NORTHERN OUTLIER WITH THIS BAND OF SNOW, SO LEANED HEAVILY ON THE GEM, GFS, AND ECMWF FOR THIS FORECAST PERIOD. THESE MODELS HAVE BEEN CONSISTENT WITH THEIR PLACEMENT OF THE BAND OVER DOWNEAST MAINE, THOUGH THEY HAVE WAFFLED A BIT WITH EXACTLY HOW HEAVY THE QPF WILL BE. HAVE THEREFORE STUCK CLOSE TO THE PREVIOUS FORECAST AS UNCERTAINTY IS A BIT HIGHER THAN ONE WOULD ANTICIPATE FOR A STORM EXPECTED IN THE NEXT 24-36 HOURS. IN ADDITION TO THE PLACEMENT OF THE CONCENTRATED BAND, ALSO COMPLICATING THE SNOWFALL TOTAL FORECAST IS THE FACT THAT TEMPERATURES WILL BE WARM ENOUGH DURING THE AFTERNOON FOR THE SNOW TO MIX WITH AND/OR CHANGE TO RAIN ACROSS SOUTHERN AND COASTAL DOWNEAST AREAS, ESPECIALLY FROM BANGOR SOUTH. FOR NOW, SNOWFALL TOTALS OF 3 TO 5 INCHES ARE EXPECTED FROM ALONG AND SOUTH OF A HOULTON TO DOVER-FOXCROFT LINE, WITH LESSER AMOUNTS AS YOU NEAR THE COAST. ISOLATED AMOUNTS OF 5+ INCHES ARE POSSIBLE, ESPECIALLY OVER NORTHERN WASHINGTON COUNTY. GIVEN THESE AMOUNTS, HAVE ISSUED A WINTER WEATHER ADVISORY FOR LATE TONIGHT THROUGH SUNDAY NIGHT FOR PORTIONS OF WASHINGTON, HANCOCK, AND PENOBSCOT COUNTIES. NORTH OF THIS AREA, 1 TO 3 INCHES OF SNOW WILL BE THE RULE, WITH 1 INCH OR LESS OVER THE FAR NORTH AND WEST. FOR SUNDAY NIGHT...THE MODEL GUIDANCE HAS REALLY SHOWED A TIGHTENING OF THE PRECIPITATION GRADIENT ON THE BACKSIDE OF THE AFOREMENTIONED SNOW BAND; IN FACT, MANY GIVE THE NORTHWESTERN THIRD OF OUR AREA A TRACE OR LESS OF QPF LATE AFTER 7PM/00Z. HAVE THEREFORE PULLED BACK TO CHANCE POPS IN THESE AREAS FOR LATER TOMORROW INTO TOMORROW NIGHT, ALONG WITH LIGHTER SNOWFALL AMOUNTS. THE HEAVIER SNOW OVER DOWNEAST WILL CONTINUE INTO THE FIRST PART OF THE EVENING, BUT WILL GRADUALLY TAPER OFF TO LIGHT SNOW TOWARD MIDNIGHT. && .SHORT TERM /TONIGHT THROUGH TUESDAY/... FOR THE SHORT RANGE...THE SUITE OF MODELS SHOW CONSIDERABLE SPREAD WITH REGARD TO THE EXACT SCENARIO OF S/WVS XPCTD TO AFFECT OUR FA. BEST WE CAN TELL...A WEAK (SECOND) S/WV WILL CROSS THE FA FROM SW TO NE BRINGING SN/SHWRS OR A PD OF LGT SN TO THE FA. HI TEMPS RECOVER WELL INTO THE 30S ACROSS ERN PTNS OF THE FA...EVEN AS FAR AS NE AROOSTOOK COUNTY BY MON AFTN AS 925-850 MB TEMPS APCH OR EVEN EXCEED 0 DEG C...SO SN COULD MIX WITH OR EVN CHG TO RN SHWRS FOR A BRIEF TM MON AFTN. SNFL AMOUNTS MON COULD REACH UP TO AN ADDITIONAL INCH OR SO. ANY LEFT OVR SHWRS SHOULD BE ALL SN BY MID EVE MON AS SFC AND TEMPS ALF COOL A LITTLE...BUT WITH LITTLE...IF ANY QPF XPCTD MON NGT...ANY CORRESPONDING SNFL SHOULD BE NEGLIGIBLE THIS PD. CLD CVR AND ERLY COMPONENT SFC WINDS SHOULD KEEP OVRNGT LOWS MILD DURG THIS TM. EVEN MORE UNCERTAINTY EXISTS WITH THE NEXT SERIES OF OF S/WVS AS SPLIT IN THE FLOW ALF DEVELOPS OVR THE NE U.S. ON TUE. ANY LEAD PRECIP WITH THESE SYSTEMS THAT ARRIVES MSLY BY TUE AFTN LOOKS TO BE ON THE LGT SIDE ATTM. MORE SO...SFC AND 925-850 MB TEMPS WILL EVEN BE MILDER THAN MON...SUGGESTING EVEN A GREATER POTENTIAL TO GO OVR TO A PD OF RN SHWRS OVR ALL XCPT PERHAPS HIER TRRN OF NW ME... REDUCING THE POTENTIAL OF ACCUMULATING SNFL ACROSS THE REGION AS A WHOLE THIS PD. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... MODEL DIVERGENCE IN THE LONG RANGE IS EVIDENT FROM THE START OF THE EXTENDED PERIOD. THESE DIFFERENCES CAN BE SEEN IN THE LOCATION/TIMING OF THE SURFACE LOW OFF THE COAST OF MAINE AND BY THE STRENGTH OF THE UPPER LEVEL LOW. THESE DIFFERENCES APPEAR TO BE ASSOCIATED WITH A TROUGH THAT WILL BE PROGRESSING EAST OUT OF THE WESTERN PORTION OF THE US. THE 12Z GFS IS MORE PROGRESSIVE WITH THE UPPER LEVEL LOW TO THE WEST THAN THE 00Z ECMWF. SINCE THERE IS STILL SOME UNCERTAINTY WILL CONTINUE WITH THE SUPERBLEND. THIS WILL BRING BEST CHANCES OF PRECIP ACROSS THE SOUTHEASTERN PORTIONS OF THE STATE TUESDAY NIGHT INTO WEDNESDAY. WEAK RIDGING WILL BUILD IN BEFORE THE SYSTEM TO THE WEST APPROACHES ALLOWING FOR SOME BRIEF BREAK THURSDAY. THERE ARE CERTAINLY STILL TIMING AND LOCATION DIFFERENCES IN THE GUIDANCE THAT WILL NEED TO BE WORKED OUT FOR LATE NEXT WEEK. THIS PERIOD WILL ALSO STICK WITH THE CONSENSUS/SUPERBLEND APPROACH. THIS WILL BRING THE NEXT BEST CHANCE OF PRECIP FRIDAY INTO SATURDAY WITH BEST CHANCES ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. HIGH AND LOW TEMPERATURES WILL BE NEAR TO LITTLE ABOVE NORMAL FOR THE PERIOD. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... NEAR TERM: VFR GOING TO MVFR OVERNIGHT AND DETERIORATE TO IFR W/PERIODS OF LIFR AS SNOW SPREADS ACROSS THE REGION THROUGH EARLY MORNING. THE SNOW AND IFR/LIFR CONDITIONS ARE EXPECTED TO CONTINUE RIGHT THROUGH 00Z MONDAY, THOUGH KBGR AND KBHB WILL TRANSITION OVER TO RAIN FOR A FEW HOURS SUNDAY AFTERNOON. IFR CONDITIONS WILL POSSIBLY LIFT AT THE NORTHERN TERMINALS AFTER 00Z MONDAY, BUT KHUL/KBGR/KBHB WILL REMAIN IFR THROUGH THE END OF THE PERIOD. SHORT TO LONG TERM: WE XPCT MVFR AT BEST OVR ALL OF THE TAF SITES WITH PDS OF IFR IN SN/RN OR STEADY LGT SN/RN FROM TUE THRU THU. && .MARINE... NEAR TERM: SEAS ARE RUNNING 2 TO 3 FT AS OF 9 PM ON THE COASTAL WATERS WITH A SSW WIND OF AROUND 15 KNOTS WITH GUSTS TO 20 KNOTS. NEAR SCA CONDITIONS ARE EXPECTED LATE TONIGHT AND SUNDAY AS LOW PRESSURE APPROACHES FROM THE NORTHWEST. SOUTH WINDS WILL INCREASE AHEAD OF THIS LOW, WITH SOME GUSTS APPROACHING 25 KT. MEANWHILE, SEAS WILL BUILD TO AROUND 4 FT. THESE CONDITIONS WILL IMPROVE SUNDAY NIGHT AS THE WEAKENS. GIVEN THE BORDERLINE NATURE OF THE WINDS AND WAVES, HAVE OPTED TO NOT ISSUE ANY HEADLINES AT THIS TIME, BUT THE SITUATION WILL HAVE TO BE WATCHED CLOSELY. SHORT TERM: INITIALLY NO HDLNS SHOULD BE NEEDED...THEN WINDS AND SEAS INCREASE BEGINNING LATE MON NGT AS LOW PRES ORGANIZES S AND E OF THE WATERS...POTENTIALLY REACHING SCA THRESHOLDS TUE AFTN... THEN CONTG INTO WED MORN BEFORE SUBSIDING LATER WED. WE USED A BLEND OF MODELS AND MOS GUIDANCE FOR WINDS AND BLENDED WW3 WITH SWAN NAM/GFS && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ011-016- 017-032. MARINE...NONE. && $$ NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
432 AM EST SUN DEC 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM EST SUN DEC 1 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER THE UPR GRT LKS TO THE SW OF UPR TROF CENTERED OVER NRN QUEBEC. IN THE WAKE OF DEPARTING SHRTWV MOVING THRU SW QUEBEC...A SHRTWV RDG IS SLIDING SEWD THRU NW ONTARIO...SUPPORTING A SFC HI PRES OVER FAR NW ONTARIO. CLOSER TO UPR MI...A LO PRES TROF IS APRNT NEAR THE LK SUP SHORE OF UPR MI AND EXTENDING WNW IN THE MN ARROWHEAD. THIS TROF HAS BEEN THE FOCUS FOR SOME BANDS OF HIER REFLECTIVITY SHOWN ON THE MQT 88D REFLECTIVITY WITH UPSLOPE N WINDS NEAR LK SUP. SINCE H85 TEMPS ARE ONLY -7 TO -8C AND THE ACCOMPANYING MSTR IS RELATIVELY SHALLOW AS DIAGNOSED FM THE MQT 88D VWP AS WELL AS THE 00Z INL RAOB...WHICH SHOWS INVRN BASE NEAR H85 UNDER VERY DRY MID LVLS AHEAD OF APRCHG SHRTWV RDG...ASSOCIATED PCPN HAS BEEN A MIX OF -SHSN AND SOME -FZDZ. THE 00Z YPL RAOB SHOWS SHALLOW MSTR AS WELL BLO AN INVRN NEAR H925...SO PLENTY OF LO CLDS EXTEND WELL N INTO ONTARIO. THE AIR IS MUCH COLDER THERE WITH SFC TEMPS IN THE TEENS...SO SPOTTY LGT PCPN IS IN THE FORM OF SN. MAIN FCST CONCERN IN THE SHORT TERM IS THE POTENTIAL FOR SOME LGT -SN AND -FZDZ. TODAY...WITH APRCH OF SHRTWV RDG NOW IN NW ONTARIO...LARGER SCALE QVECTOR DVGC/MID LVL DRYING IS FCST TO SLOWLY WEAKEN...BUT NOT ELIMINATE ALTOGETHER...THE SFC TROF NOW OVER LK SUP AND INHIBIT ANY LARGER SCALE PCPN. SFC HI PRES NOW OVER FAR NW ONTARIO IS PROGGED TO DRIFT ONLY SLOWLY SE ACRS NRN ONTARIO...WITH THE CWA DOMINATED BY WEAKENING AND SLOWLY VEERING LLVL NE FLOW. WL CONT TO CARRY SOME CHC POPS NEAR LK SUP IN AREA THAT WL EXPERIENCE AN UPSLOPE WIND COMPONENT NEAR LINGERING LO PRES TROF OVER THE NCENTRAL. WHETHER THIS PCPN IS ALL -SN OR REMAINS MIXED WITH SOME -FZDZ IS THE PRIMARY CONCERN. MODELS REMAIN INCONSISTNET ON FCST H85 TEMPS AND MSTR DEPTH. FCST H85 TEMPS ARE FCST TO FALL TO ARND -9C BY THE 00Z NAM/LOCAL WRF-ARW TO -11C BY THE GFS. GIVEN THE WEAKENING WINDS THAT WL LIMIT LLVL CAD AND EXPECTED NEGATIVE DYNAMICS AS WELL AS UPSTREAM RAOBS...PREFER THE SOMEWHAT WARMER H85 TEMPS AND SHALLOWER MSTR PROFILE/LOWER INVRN BASE SHOWN BY THE 00Z LOCAL WRF-ARW MODEL. THIS MODEL SHOWS THE UPSLOPE UVV AND INVRN BASE REMAINING NR 5K FT AGL AND BLO THE DGZ... SO WL RETAIN A MIX OF -SN/-FZDZ THRU THE DAY. MARGINAL H85 TEMPS RELATIVE TO LK WATER TEMP ARND 4C WL LIMIT ANY SN ACCUM. WITH PLENTY OF LO CLDS...TEMPS SHOULD REBOUND ONLY SLIGHTLY THRU THE DAY. TNGT...VERY LGT LLVL WINDS ARE PROGGED TO SLOWLY VEER TO THE E AND SE AS THE CENTER OF SFC HI PRES SHIFTS INTO QUEBEC. SUSPECT LINGERING LK EFFECT PCPN WL DRIFT INTO THE KEWEENAW AS THE FLOW GRDLY SHIFTS TO THE ESE. IN THE ABSENCE OF ANY DYNAMIC SUPPORT... EXPECT THE INVRN BASE TO REMAIN NEAR 5K FT. AS POINTED OUT BY THE DAYSHIFT...LK VORTICES OFTEN DVLP WITH THE FCST LGT LLVL WINDS. BUT MARGINAL H85 TEMPS ARND -9C WL LIMIT THE INTENSITY OF ANY SHSN THAT WOULD ACCOMPANY THESE FEATURES...AND THE LGT WINDS WL INHIBIT BANDING. SO ANY SN ACCUMS SHOULD REMAIN LGT. SINCE THE H85 TEMPS WL REMAIN MARGINAL FOR LES AND UPSLOPE OMEGA WL REMAIN BLO THE DGZ...INCLUDED A MENTION OF FZDZ. LINGERING LO CLDS WL LIMIT THE DIURNAL TEMP FALL. BEST CHC FOR SOMEWHAT LOWER TEMPS WL BE OVER THE E WITH A RELATIVELY UNMODIFIED/DOWNSLOPE E FLOW OFF ONTARIO THAT MIGHT ALLOW FOR SOME BREAKS IN THE SC. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 430 AM EST SUN DEC 1 2013 MONDAY THROUGH TUESDAY MORNING...UPPER LEVEL 500MB TROUGHING IS EXPECTED TO REMAIN IN PLACE ACROSS THE CWA THROUGH THIS TIME PERIOD AS A WEAK INVERTED RIDGE WEDGES IN ACROSS THE AREA AT THE SURFACE. A SLIGHTLY DRYER AIRMASS WILL ALSO LINGER THROUGH TUESDAY MORNING WHICH CAN BE SEEN BY ANALYZING 1000-500MB RH. THE NEXT SURFACE LOW CAN BE SEEN PUSHING ACROSS THE NORTHERN ROCKIES MONDAY NIGHT AND EJECTING INTO THE NORTHERN OR CENTRAL PLAINS TUESDAY MORNING AS A MUCH DEEPER UPPER LEVEL 500MB TROUGH BUILDS IN OVER THE WESTERN U.S. THERE ARE STILL SOME MODEL DIFFERENCE HOWEVER WITH THE 00Z GFS/NAM BEING A BIT FASTER AND STRONGER WITH THIS LOW. THE 00Z GFS/NAM PLACE THE SURFACE LOW ALONG THE NORTH AND SOUTH DAKOTA BORDER BY 12Z ON TUESDAY. THE 00Z EC/GEM ARE THE SLOWER OF THE SOLUTIONS KEEPING THE LOW A BIT FARTHER SOUTH AND REMAINING OVER THE CENTRAL PLAINS JUST A BIT EAST OF THE ROCKIES. EITHER WAY...BOTH SOLUTIONS KEEP THE PRECIPITATION TO THE WEST OF THE AREA THROUGH THIS TIME PERIOD. LIGHT EASTERLY WINDS THROUGH MONDAY NIGHT WILL SLOWLY BECOME SOUTHEASTERLY BY TUESDAY. THIS ALONG WITH H850 TEMPS AROUND -8 TO -10 C WILL HELP TO KEEP CONDITIONS CLOUDY WITH VERY LIGHT PRECIPITATION POSSIBLE...MAINLY OVER THE KEWEENAW PENINSULA. TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...THIS TIME PERIOD REMAINS UNCERTAIN WHICH HAS BEEN THE CASE OVER THE PAST SEVERAL DAYS...WITH POOR MODEL AGREEMENT EVEN AS THIS TIME PERIOD IS RAPIDLY APPROACHING...HOWEVER...THE 00Z EC TENDS TO BE TRENDING A BIT CLOSER TO THE NAM AND GFS SOLUTIONS. THE GFS/NAM SOLUTIONS BRING INCREASED MOISTURE AND PRECIPITATION INTO THE CWA BY 18Z TUESDAY...WHILE THE EC/CANADIAN KEEP THE SYSTEM CENTERED OVER NORTHEASTERN KS DURING THAT TIME FRAME. THE 00Z GFS PLACES THE SURFACE LOW AND VERTICALLY STACKED CLOSED UPPER LEVEL 500MB LOW OVER WESTERN WI AT 00Z WED WHILE THE 00Z EC HAS THE MORE ELONGATED SURFACE LOW OVER CENTRAL IOWA INTO CENTRAL PLAINS. BY 18Z WED THE 00Z RUN OF THE GFS PUSHES THE LOW TO THE NORTHEAST OF LAKE SUPERIOR WHILE THE EC IS JUST PLACING THE SURFACE LOW AND UPPER LEVEL ENERGY INTO THE WESTERN PORTION OF WI. DEFINITELY EASY TO SEE THAT THERE ARE STILL SIGNIFICANT DIFFERENCES BETWEEN THESE MODELS...HOWEVER...A BETTER SIGNAL EXISTS SINCE THE EC IS TRENDING A BIT CLOSES TO THE FASTER SOLUTIONS...THE BEST IDEA FOR THE TIME BEING WILL BE MORE OF A MIDDLE OF THE ROAD APPROACH...WITH A SLIGHT LEAN TOWARD THE FASTER SOLUTIONS. THIS WOULD FAVOR A LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT TIME FRAME FOR THE MORE CONCENTRATED AREA OF PRECIPITATION. SOUNDINGS FOR THIS TIME PERIOD INDICATE WARMER AIR LIFTING NORTHWARD ON THE EAST SIDE OF THE LOW HELPING TO TRANSITION THE PRECIPITATION OVER TO A RAIN SNOW MIXTURE FOR AT LEAST THE EASTERN HALF OF THE UPPER PENINSULA AS A FAIRLY DEEP WARM LAYER BUILDS IN THROUGH MUCH OF THE BOUNDARY LAYER. THE FAR WESTERN PORTION OF THE U.P. MAY END UP SEEING MAINLY SNOW AS SHOWN BY ANALYZING BOTH THE EC AND GFS PROFILES. IN ANY CASE THIS SYSTEM WILL BE CLOSELY WATCHED OVER THE NEXT SEVERAL MODEL RUNS TO SEE IF BETTER UPPER AIR SAMPLING CAN ENTERTAIN GREATER MODEL AGREEMENT. THURSDAY THROUGH SATURDAY...ATTENTION TURNS TO A POTENTIALLY PROLONGED PERIOD OF LAKE EFFECT SNOW. MODELS ACTUALLY BECOME IN BETTER AGREEMENT WITH THE SYSTEM DURING THIS TIME FRAME. EACH OF THE MODELS SHIFT THE SURFACE LOW NORTHEASTWARD TO NEAR JAMES BY BY 12Z THURSDAY. AS THIS HAPPENS WINDS WILL SHIFT TO THE WEST ALLOWING LAKE EFFECT SNOW TO DEVELOP IN AREAS FAVORED BY THAT PARTICULAR WIND DIRECTION. THURSDAY THROUGH THURSDAY NIGHT THE LAKE EFFECT SNOW WILL PROBABLY JUST BE STARTING ACROSS THE AREA...BUT SHOULD REMAIN LIGHT. TRIED TO TREND THE LES CHANCES UPWARD FRIDAY THROUGH SATURDAY AS AN UPPER LEVEL TROUGH/SHORTWAVE AND INCREASED MOISTURE SHIFTS INTO THE AREA...ALLOWING FOR ENHANCED LIFT FOR LES TO DEVELOP. ITS STILL A BIT TOO EARLY TO TELL FOR SURE ABOUT THE OVERALL SNOWFALL TOTALS...BUT IT DOES LOOK LIKE FRIDAY INTO SATURDAY WILL BE SNOW FOR WESTERLY WIND FAVORED AREAS OF THE UPPER PENINSULA. AS EARLIER SHIFT STATED THE SNOW TO LIQUID RATIOS WILL LIKELY BE SLIGHTLY LOWER THAN USUAL FOR LES AS THE DGZ IS FAIRLY SHALLOW AND FAIRLY LOW IN THE ATMOSPHERE...WHICH TENDS TO INHIBIT THE MORE FAVORABLE GROWTH RATES FOR SNOW. STAY TUNED THOUGH AS THIS LES EVENT GETS CLOSER TOWARD THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1208 AM EST SUN DEC 1 2013 COOLER AIR MOVING ACROSS LAKE SUPERIOR BEHIND A LOW PRESSURE SYSTEM HAS RESULTED IN A MIX OF LIGHT LAKE EFFECT SNOW AND FREEZING DRIZZLE ACROSS NW AND NCNTRL PORTIONS OF THE FCST AREA THIS EVENING. EXPECTATION IS THAT THE SNOW/FZDZ WILL CAUSE MVFR TO IFR CONDITIONS AT TAF SITES OVERNIGHT. A HIGH PRESSURE RIDGE MOVING OVER LAKE SUPERIOR OVERNIGHT WILL SLOWLY VEER THE WINDS TO THE NORTH-NORTHEAST AND LEAD TO LESS FAVORABLE WIND DIRECTIONS FOR KCMX/KIWD SO WILL CONTINUE TO SHOW A DIMINISHING TREND IN SNOW SHOWERS AND RAISE CEILINGS SOMEWHAT BUT STILL IN MVFR RANGE. CONFIDENCE IN SNOW SHOWER LOCATION/STRENGTH DIMINISHES LATE TONIGHT INTO SUNDAY...DUE TO WINDS BECOMING LIGHT AND VARIABLE THROUGH THE DAY. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 430 AM EST SUN DEC 1 2013 EXPECT NE WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH UNDER 15 KTS AND SLOWLY VEER INTO MON AS A WEAK PRES GRADIENT EXTENDING S FROM HI PRES MOVING THRU ONTARIO DOMINATES THE UPPER LAKES. STRONGER E TO SE WINDS UP TO 25 TO PERHAPS 30 KTS WILL THEN DEVELOP INTO MID WEEK AS THE GRADIENT SHARPENS OVER LAKE SUP BETWEEN THE HI PRES SHIFTING INTO QUEBEC AND LO PRES MOVING NE FROM THE PLAINS. THERE WILL BE A SHARP WIND SHIFT TO THE WNW BY THU FOLLOWING THE PASSAGE OF THE LO TO THE NE. DEPENDING ON THE TRACK AND INTENSITY OF THIS LO...THERE COULD BE A W GALE ON THU INTO FRI. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KEC AVIATION...VOSS MARINE...KC
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1145 PM EST SAT NOV 30 2013 .AVIATION... //DISCUSSION... PLENTY OF MID LAYER CLOUD FOR THE OVERNIGHT HOURS. THERE IS AN AREA OF MVFR CIGS AROUND THE FRONT AND THIS WILL MOVE INTO THE TAF SITES ON SUNDAY MORNING FOR MBS AND FNT...BUT NOT UNTIL THE AFTERNOON FOR THE SOUTHERN TAF SITES. ANY PRECIPITATION WITH THE FRONT WILL BE LIMITED. WILL BRING A FEW HOURS OF LIGHT PRECIPITATION FOR THE NORTHERN SITES...WITH ONLY MBS HAVING THE POTENTIAL TO HAVE MVFR VSBY. WITH A LOOK AT THE CURRENT SOUNDING AT DTX AND MODEL SOUNDINGS... WILL ADD SOME MIXED RAIN AND SNOW. FOR DTW...DRY AIRMASS PRE COLD FRONT TONIGHT WILL KEEP CLOUDS ABOVE 5000 FT. MVFR CLOUD WILL THEN SETTLE OVER THE TAF SITE DURING SUNDAY LATE MORNING AND EARLY AFTERNOON IN RESPONSE TO LOW LEVEL COLD AIR ADVECTION. //DTW THRESHOLD THREATS... * LOW CONFIDENCE IN CEILING HEIGHTS BELOW 5000 FT PRIOR TO 15Z SUNDAY. HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET SUNDAY AFTERNOON. && .PREV DISCUSSION...ISSUED 916 PM EST SAT NOV 30 2013 UPDATE... CURRENT CONDITIONS ARE CERTAINLY SUPPORTIVE OF FOLLOWING THE PREVIOUS FORECASTS THOUGHTS ON LOWER CHANCES OF PRECIPITATION THAN WHAT THE 12Z AND 18Z MODELS ARE SUGGESTING. NEARLY ALL OF THE RADAR RETURNS OVER LOWER MICHIGAN ARE VIRGA. LATEST RUC RUNS ARE MORE SUPPORTIVE OF A DRIER OVERNIGHT AND ARE REALLY IN LINE WITH THE CURRENT FORECAST POPS...CLOUDS AND QPF. 00Z SOUNDINGS AND THE LATEST RUC SOUNDINGS SUGGEST THAT IT WILL TAKE SOME TIME TO SATURATE THE LAYER BETWEEN 3K AND 6K FEET. WHILE THERE IS SOME MOISTURE ALONG THE FRONT BELOW 3K FEET...IT IS REALLY ABOVE THIS THAT DRY AIR REMAINS IN PLACE TO LIMIT PRECIP. THE OTHER ITEM THAT SHOWS WELL IN THE SOUNDINGS IS THAT THE FREEZING LEVEL WILL LIKELY BE 1000 TO 2000 FEET ABOVE THE SURFACE WHEN WE FIRST SATURATE. ANY PRECIP THAT HAS FALLEN ACROSS NRN LOWER THIS EVENING HAS BEEN RAIN. THEREFORE WILL BRING IN A MIX OF RAIN...AT LEAST AT THE START...FOR ANY PLACE THE DOES GET SOME PRECIP OVERNIGHT. WILL RAISE TEMPS JUST A BIT OVERNIGHT DUE TO THE COMBINATION OF THE CLOUDS AND SOUTHERLY WIND AHEAD OF THE COLD FRONT. TEMPS WILL EVENTUALLY REACH THEIR FORECAST LOWS WITH THE FRONTAL PASSAGE OR WITH THE EVAPORATE COOLING. THE EXCEPTION WILL BE IN THE FAR SOUTH OF THE FORECAST AREA WHERE MOSTLY CLEAR SKIES ARE ALLOWING TEMPS TO FALL. PREV DISCUSSION...ISSUED 319 PM EST SAT NOV 30 2013 SHORT TERM...TONIGHT A THERMAL WAVE DIGGING SOUTHEASTWARD ALONG THE TRAILING EDGE OF NE NORTH AMERICAN UPPER LEVEL TROUGH WILL BE THE WEATHER AFFECTING THE CENTRAL GREAT LAKES TONIGHT. THE CYCLONIC VORTICITY ENERGY ASSOCIATED WITH THE SHORT WAVELENGTH THERMAL RIDGE IS FRAGMENTED WITH THE INITIAL SHORTWAVE DAMPENING WHILE IT PUSHES EAST OF LAKE SUPERIOR THIS AFTERNOON. A SECOND SHORTWAVE IS NOW SLIDING THROUGH THE MINNESOTA ARROWHEAD AND INTO THE FAR WESTERN LAKE SUPERIOR BASIN TAKING OVER WITH TIME. THIS SHORTWAVE WILL PROVIDE A NECESSARY FORCING COMPONENT AFTER 9Z OVER THE FAR NORTHERN CWA WHICH SHOULD FINALLY ALLOW PRECIPITATION TO FALL. OTHERWISE THE MIX OF DYNAMICS SUPPORTIVE OF ASCENT IS LIMITED. ANALYSIS OF 285K SYSTEM RELATIVE ISENTROPIC ASCENT IS VERY UNINSPIRING DESPITE SOME LINKAGE OF RIGHT ENTRANCE REGION DYNAMICS ALOFT WITH 850-700MB DEFORMATION. THE DEFORMATION IS MODELED TO BE ASSOCIATED WITH THE CONVERGENCE FEATURE OF THE FRONT. EXPECT THIS FORCING TO STRIPE FOR A VERY LIMITED TIME FROM WEST TO EAST NORTHEAST...PRIMARILY ACROSS THE FAR NORTHERN COUNTIES. WET BULB AND OFFERED BUFKIT SOUNDINGS SUPPORT AN ALL SNOW EVENT...TRENDED TO ALL SNOWFLAKES. A DUSTING WILL BE POSSIBLE NORTH AFTER 8Z...PERHAPS A HALF TO 1 INCH IN THE NORTHERN THUMB. LONG TERM...SUNDAY THROUGH NEXT SATURDAY MID LEVEL ENERGY IS FORECAST TO RAPIDLY SHEER TO THE EAST OF THE AREA LATE SUNDAY MORNING. THE 12Z MODEL SUITE ALL SUGGEST THE ASSOCIATED MID LEVEL ASCENT WILL RESIDE ALONG THE 1-69 CORRIDOR INTO THE THUMB REGION BY 12Z BEFORE QUICKLY WANING BY NOON. BOTH NAM AND GFS APPEAR TOO AGRESSIVE IN MOISTENING THE LOW LEVELS...SUGGESTING THAT WET BULB COOLING MAY BE STRONG ENOUGH TO KEEP ANY LINGERING MORNING PRECIP AS LIGHT SNOW. UPSTREAM OBSERVATIONS DO HOWEVER SUPPORT MODEL SOLUTIONS WHICH BRING A POST FRONTAL LOW STRATUS DECK INTO THE AREA FOLLOWING THE PASSAGE OF A WEAK SURFACE COLD FRONT. THESE LOW CLOUDS ARE EXPECTED TO ENVELOPE THE TRI CITIES AND THUMB BY DAYBREAK...THEN OVERSPREAD METRO DETROIT EARLY SUN AFTERNOON. OVERALL WEAK POST FRONTAL COLD AIR ADVECTION WILL SUPPORT SUN MAX TEMPS IN THE MID/UPPER 30S ACROSS THE NORTH AND LOW 40S SOUTH OF THE I-96/696 CORRIDOR. THE DEPTH OF THE POST FRONTAL COLD AIR SUN AFTERNOON WILL BE GREATER OVER LAKE HURON...WHICH WILL RESULT IN A DEEPENING CONVECTIVE DEPTH OVER THE LAKE. MODEL SOLUTIONS SUGGEST A GOOD RESPONSE OFF THE LAKE...ENOUGH TO SUPPORT A CHANCE OF SNOW SHOWERS OVER THE THUMB SUN AFTERNOON INTO SUNDAY EVENING AS THE FLOW TURNS TOWARD THE NE. THE EXPECTED DEGREE OF VARIABILITY IN THE LOW LEVEL WIND DIRECTION DOES NOT SUPPORT A PROLONGED CONVERGENT BAND...SO FORECAST ACCUMS WILL BE KEPT MINIMAL. MID LEVEL SUBSIDENCE WILL LOWER INVERSION HEIGHTS SUN NIGHT AND WILL MAINTAIN THE LOW STRATUS OVER THE REGION. CONTINUED LOW LEVEL MOISTURE FLUX UNDER THE NE FLOW MAY HOWEVER SUPPORT SOME DRIZZLE SUN NIGHT INTO MON MORNING OVER A GOOD PORTION OF SE MI. CONFIDENCE IS NOT QUITE HIGH ENOUGH TO ADD DRIZZLE TO THE ZONE/GRIDS AT THIS POINT...BUT IS SOMETHING LATER SHIFTS WILL HAVE TO MONITOR. AMPLE LOW CLOUDS AND WEAK LOW LEVEL THERMAL ADVECTION IS LIKELY TO HOLD TEMPS IN THE 30S SUN NIGHT INTO MON MORNING. A LOW AMPLITUDE MID LEVEL TROUGH IS FORECAST TO TRAVERSE THE OHIO VALLEY ON MONDAY. DESPITE THE OVERALL WEAK FORCING WITH THIS FEATURE...MODEL SOLUTIONS DO SUGGEST A HEALTHY SURGE OF MID LEVEL MOISTURE INTO SRN MI. THIS COUPLED WITH THE EXPECTED STRATUS AND WEAK LARGE SCALE ASCENT MAY BE ABLE TO GENERATE A FEW LIGHT SNOW AND/OR RAIN SHOWERS. SOUTHEAST MICHIGAN CONTINUES TO BE ON A ROLLER COASTER AS FAR AS TEMPERATURES ARE CONCERNED WITH TEMPS WARMING THROUGH THURSDAY BEFORE COOLING OFF BY THE WEEKEND. UPPER LEVEL RIDGE WILL WORK INTO THE AREA TUESDAY HELPING TO KEEP THINGS ON THE DRIER SIDE. PRECIP CHANCES START TO INCREASE WEDNESDAY AS A LOW TRAVERSES OVER THE NORTHERN GREAT LAKES. SOUTHERLY FLOW OUT AHEAD OF THIS SYSTEM WILL HELP TO BRING IN MOISTURE AND WARMER AIR. PRECIP TYPE WILL LIKELY START OFF AS SNOW BEFORE QUICKLY TRANSITIONING TO ALL RAIN AS WARMER TEMPS OVERSPREAD THE AREA. BETTER CHANCE FOR MEASURABLE PRECIP WILL COME THURSDAY INTO FRIDAY AS ANOTHER LOW DEVELOPS AND MOVES TOWARDS THE GREAT LAKES. CURRENTLY THIS LOW LOOKS TO TRACK SOUTH OF MICHIGAN WHICH WOULD PUT THE CWA IN THE COLD SECTOR WITH SNOW BEING THE MAIN PRECIP TYPE. COOLER TEMPS MAKE A RETURN NEXT WEEKEND AS WESTERLY FLOW INCREASES OVER SOUTHEAST MICHIGAN. MARINE... THE SOUTHERLY WINDS WILL DIMINISH DURING THE COURSE OF THE EVENING AS THE GRADIENT RELAXES. THIS WILL OCCUR AS A WEAK AREA OF LOW PRESSURE EXPANDS ACROSS LAKE HURON TONIGHT. THIS LOW WILL ADVANCE INTO ONTARIO ON SUNDAY WHICH WILL CAUSE THE WINDS TO TURN NORTHEASTERLY OVER LAKE HURON. WIND SPEEDS WILL INCREASE DURING THE AFTERNOON. GUSTS SHOULD REMAIN AT OR BELOW 25 KNOTS. THE GRADIENT WILL THEN RELAX BY MONDAY. WEAK HIGH PRESSURE WILL RESULT IN LIGHT WINDS INTO WEDNESDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....JVC UPDATE.......JVC SHORT TERM...CB LONG TERM....SC/SS MARINE.......SC YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
339 AM CST Sun Dec 1 2013 .SHORT TERM: (Through Late This Afternoon) Issued at 335 AM CST Sun Dec 1 2013 Think the challenge for today will be forecasting cloud cover. A stratus deck between 4000-5000ft is moving across he eastern Ozarks and parts of Southern Illinois this morning. Think this area of stratus will continue advecting eastward faster than the western edge will erode as has been the case for the past few hours. Therefore there should be substantial cloud cover over southeast Missouri and parts of southern Illinois this morning. The 00Z NAM eventually cleared it out and this matches well with satellite trends at this time; however the RAP backbuilds the cloud cover, as does the 06Z NAM and this suggests that areas generally southeast of a line from Vichy, MO to Salem, IL may not see much sun today. Am sticking closer to the less cloudy solution at this time, but this may ultimately prove to be too optimistic. Temperatures may be challenging as well. Can`t seem to forecast warm enough the past couple of days. Missed highs both Friday and Saturday by to to three degrees. Lingering cloud cover over the eastern Ozarks and southwest Illinois may make this especially challenging. For highs today, used a blend of 925 mix-down temperatures and MOS. Tweaked southern zones down a couple of degrees from that to account for cloud cover, and the rest of the area up a degree or two to try to compensate for my apparent cool bias. Britt .LONG TERM: (Tonight through Saturday) Issued at 335 AM CST Sun Dec 1 2013 (Tonight - Tuesday) Have not made too many changes to going forecast during this period. Low level moisture progs suggest that stratus will redevelop this evening, particularly over the southern and eastern part of the CWA. Have kept chance of light drizzle in these areas where this moisture will be the deepest and there will be some very light ascent. As we go into Monday, GFS/NAM/ECMWF all show a weak shortwave trough racing into the area from the west, though it is not as deep as was forecast 24 hours ago. Have left chance of sprinkles in for tomorrow morning as the trough axis will move through the area by midday. Temperatures will begin to warm up ahead ahead of the next storm system. Expect temperatures to climb into the 50s on Monday with some spots reaching 60 on Tuesday. (Wednesday - Saturday) Main concern continues to be the potential for a wintry precipitation and the big cool down mid to late week. There still ia a great deal of uncertainty regarding timing, precipitation types and amounts. While the GFS is still the fastest with the passage of the cold front, the 00Z ECMWF now brings the cold front through the area during the day on Wednesday instead of Wednesday Night. The cold front will have moved to the south of the area Wednesday. Best forcing for precipitation will hinge on mid-level frontogenesis and shortwave troughs moving through fast west- southwesterly flow aloft. Have likely pops on Thursday and Thursday Night over southeastern half of the CWA with the chance continuing into Friday. Will continue to have a simple mix of rain and snow because of the uncertainty for now, but thermal profiles from forecast soundings certainly suggest the potential for sleet or freezing rain over the southern half of the CWA. 850mb temperatures by next Friday and Saturday will be in the -10 to -12C range supporting highs only in the 20s with lows in the single digits and teens. Britt && .AVIATION: (For the 06z TAFs through 06z Sunday Night) Issued at 1133 PM CST Sat Nov 30 2013 Weak surface frontal boundary extending from central Michigan through far northwest Illinois and then becoming stationary over northern Kansas. Front is expected to move southeast and move through UIN-COU areas between 0900 and 1100 UTC and through STL area after 1400 UTC. Scattered to broken area of clouds will move through the southern half of Missouri from 0600 - 1100 UTC. Scattered area of clouds will be east of COU and south of UIN areas. Surface winds will shift from WSW to NW direction after passage of front. Wind speeds will range from 4 to 7 kts. Specifics for KSTL: Scattered to broken layer of clouds at 040 will move through STL area between 0600 and 0900 UTC. Surface winds will be light southwest then shift to West-northwest direction around 5 kts after 1400 UTC. Clouds will remain scattered 040 with higher broken deck aob 200. Surface winds will shift to north-northwest by early afternoon with speeds o0f 4 to 6 kts. Przybylinski && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS RALEIGH NC
303 AM EST SUN DEC 1 2013 .SYNOPSIS... HIGH PRESSURE REMAINS OVER THE REGION TODAY. LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST TONIGHT AND GRADUALLY STRENGTHENS AS IT MOVES AWAY FROM THE REGION MONDAY. HIGH PRESSURE THEN RETURNS FOR TUESDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 300 AM SUNDAY... THE SURFACE RIDGE AXIS EXTENDED NORTHEAST TO SOUTHWEST ACROSS CENTRAL NORTH CAROLINA...WITH A SLACK GRADIENT IN PLACE. IN A FAST WESTERLY FLOW ALOFT...AS ONE MID-LEVEL SHORTWAVE EXITED CENTRAL NORTH CAROLINA TO THE EAST...ANOTHER WAS MOVING IN FROM THE TENNESEE VALLEY. THE 00Z RAOB ANALYSIS SHOWED GREATER 850MB AND 700MB MOISTURE JUST TO OUR SOUTH...AND SOME OF THIS MOISTURE HAS ADVECTED NORTH...TO ABOUT U.S. 64. THE NAM AND THE GFS ARE FAIRLY SIMILAR AND BOTH HAVE TRENDED DRIER CERTAINLY FROM THE PREVIOUS 00Z RUN...SUCH THAT THE MID LEVELS TEND TO BE FAIRLY DRY FOR MUCH OF THE DAY TODAY...WITH THE GREATEST MID-LEVEL MOISTURE OVER THE SOUTHERN COASTAL PLAIN RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA. THE BEST 850MB LIFT IS CERTAINLY IN THE SOUTHEAST PART OF CENTRAL NORTH CAROLINA TODAY WHERE 850MB THETA-E ADVECTION IS GREATEST. FAINT RADAR RETURNS AND GUIDANCE FROM THE HRRR WRF SUGGEST A SMALL CHANCE OF SPRINKLES IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN THIS MORNING...WITH A CHANCE OF RAIN MAINLY THIS AFTERNOON ALONG AND SOUTH OF A LINE FROM ABOUT KRWI TO KRCZ...WITH THE BEST CHANCE TOWARD KCTZ IN VICINITY OF GREATER MOISTURE AND LIFT. PRECIPITATION...IF ANY...SHOULD BE LIGHT...WITH THE GREATER PROBABILITY OF PLURAL HUNDREDTHS IN SAMPSON AND POSSIBLY INTO WAYNE COUNTIES AS OF THIS WRITING. 1000-850MB THICKNESSES WOULD SUPPORT WARMER TEMPERATURES THAN FORECAST BY ABOUT A CATEGORY...BUT A BLEND OF GUIDANCE WORKED WELL FOR SATURDAY HIGHS...AND WILL FOLLOW THE SAME FOR TODAY. FEWER AND THINNER CLOUDS NORTHWEST...MORE TOWARD THE SOUTHEAST BUT WITH HIGHER THICKNESSES AND MORE MOIST...RESULT IN A FAIRLY UNIFORM TEMPERATURE FORECAST IN THE LOWER TO POSSIBLY MID 50S. WINDS SHOULD BE LIGHT...WITH THE RELATIVELY GREATER SPEEDS TOWARD THE TRIAD...WHILE STILL UNDER 10KT...FROM THE SOUTHWEST...WEST OF THE SURFACE RIDGE AXIS. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... AS OF 300 AM SUNDAY... AGAIN THE NAM AND GFS ARE FAIRLY SIMILAR IN THE EVOLUTION OF THE SURFACE LOW ALONG THE COAST...WITH AN INVERTED TROUGH DEVELOPING EARLY TONIGHT FOLLOWED BY WEAK CYCLOGENESIS OVERNIGHT...THEN LOW PRESSURE GRADUALLY STRENGTHENING MONDAY AS IT MOVES AWAY FROM THE COASTAL CAROLINAS. 850MB LIFT IS NOT VERY STRONG OVERNIGHT INTO MONDAY AFTERNOON...WITH THE GFS IN PARTICULAR HAVING TRENDED FARTHER SOUTH WITH THE PASSAGE OF ITS MODERATE MID-LEVEL SHORTWAVE ACCOMPANYING THE MID-LEVEL TROUGH. JET SUPPORT ALSO LOOKS TO HAVE SHIFTED FARTHER SOUTH COMPARED TO RECENT RUNS. K INDICES ARE HIGHEST TOWARD THE COAST LATE TONIGHT AND MONDAY MORNING...BUT 850MB THETA-E STILL REMAINS MODEST WEST THROUGH THE COASTAL PLAIN...AND WITH THE WEAK LIFT AS LOW PRESSURE ORGANIZES JUST OFFSHORE...WILL CONTINUE AT LEAST A CHANCE OF RAIN EARLY TONIGHT MAINLY EAST OF INTERSTATE 95 WHEN OVERALL MOISTURE APPEARS HIGHEST FOR THE NIGHTTIME HOURS... THEN AGAIN MAINLY MONDAY MORNING ALONG AND EAST OF ABOUT U.S. 1 DURING A PERIOD OF A MODEST INCREASE IN MID-LEVEL MOISTURE IN CONJUNCTION WITH GOOD LOWER-LEVEL MOISTURE. FOR NOW WILL KEEP CHANCES BELOW LIKELY GIVEN THE DRIER MODEL TRENDS...NO MOS GUIDANCE IN CENTRAL NORTH CAROLINA CLOSE TO LIKELY...AND NAM AND GFS MODEL QPF BEING PRETTY LOW. PLAN TO KEEP THE TRIAD AND THE FAR WESTERN PIEDMONT DRY THIS PERIOD. 850MB THETA-E TROUGHINESS STARTS TO PUSH EAST MONDAY AFTERNOON WITH INCREASING SUBSIDENCE. BUFR SOUNDINGS ARE FAIRLY STABLE AND DRYING CERTAINLY BY 00Z TUESDAY...AND PRECIPITABLE WATER VALUES ARE AT OR BELOW A HALF-INCH MONDAY NIGHT. WILL NOTE CHANCES BELOW SLIGHT IN CENTRAL NORTH CAROLINA BY 00Z TUESDAY. LOWS TONIGHT AND HIGHS MONDAY ARE A LITTLE TRICKY GIVEN THE UNCERTAINTY SURROUNDING CLOUD COVER AND THE POTENTIAL VARIABLE THICKNESS OF SUCH CLOUD COVER. OPTED TO TRIM LOWS TONIGHT SLIGHTLY ESPECIALLY ALONG AND NORTH OF INTERSTATE 85 WHERE CLOUD COVER SHOULD BE LEAST AND THINNEST OVERNIGHT. GIVEN THE DRIER MODEL TREND OPTED TO RAISE MAXES INTO THE 50S THROUGHOUT CENTRAL NORTH CAROLINA MONDAY...STILL KEEPING THE WARMER READINGS OVER THE WESTERN PIEDMONT FOR NOW. OVERNIGHT LOWS MONDAY NIGHT NEAR THE COOLER MAV MOS GUIDANCE ANTICIPATING FEWER CLOUDS...LOWER TO MID 30S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 300 AM SUNDAY... WEAK HIGH PRESSURE WILL BUILD INTO THE REGION ON TUESDAY IN THE WAKE OF THE DEPARTING COASTAL CYCLONE AS A WESTERLY FLOW DEVELOPS ALOFT. FAIR WEATHER IS EXPECTED IN CENTRAL NC WITH A FEW LAYERS OF CLOUDS. HIGHS WILL RANGE IN THE LOWER 50S NORTHEAST TO NEAR 60 TOWARD THE SC BORDER. HEIGHTS BEGIN RISING ON WEDNESDAY AND THURSDAY AS A BROAD TROUGH DEVELOPS IN THE ROCKIES AND THE NORTHERN PLAINS. AN INCREASINGLY MOIST SOUTHERLY FLOW WILL PROMOTE AN INCREASE IN CLOUDINESS ON WEDNESDAY AND THURSDAY WITH WARMING TEMPERATURES ESPECIALLY ON THURSDAY. BOTH THE EC EFS AND THE GFS HIGHLIGHT A SHALLOW DISTURBANCE THAT WILL MOVE NORTHEAST ACROSS THE AREA ON WEDNESDAY THAT SHOWS UP AS A REGION OF ISENTROPIC UPGLIDE IN THE 290-295 LAYER. DON`T EXPECT ANY PRECIPITATION AT THIS TIME BUT HAVE INCREASED CLOUD PERCENTAGES DURING THE PERIOD. GFS BUFR SOUNDINGS ALSO SUGGEST THAT THERE COULD BE SOME GUSTY WINDS ON WEDNESDAY AFTERNOON WITH GUSTS UP TO 20-25 MPH AS MIXING TAPS INTO THE STRONGER FLOW ASSOCIATED WITH THE LOW LEVEL JET. A SLIGHTLY BETTER CHANCE OF RAIN ARRIVES IN THE NORTHWESTERN PORTION OF THE FORECAST AREA LATE THURSDAY AND ESPECIALLY THURSDAY NIGHT AS A COLD FRONT APPROACHES THE REGION FROM THE WEST. TEMPERATURES SHOULD WARM INTO THE MID 50S TO NEAR 60 ON ON WEDNESDAY AND THEN THE 60S TO NEAR 70 ON THURSDAY. DIFFERENCES IN THE GFS AND EC EFS BECOME MORE APPARENT ON FRIDAY AND ESPECIALLY SATURDAY WITH THE GFS BEING FASTER AND PUSHING THE FRONT THROUGH THE AREA LATE FRI/EARLY SAT WITH THE EC PERHAPS 12 HOURS SLOWER. WHILE THE BEST FORCING FOR ASCENT STAYS NORTH OF THE AREA...THE PLUME OF DEEP LAYER MOISTURE AND FORCING ASSOCIATED WITH THE FRONT SHOULD BE SUFFICIENT FOR CHC POPS. MILD TEMPERATURES ARE EXPECTED ON FRIDAY AHEAD OF THE FRONT AND AHEAD OF THE MAIN AREA OF RAIN. MAX TEMPS HAVE BEEN ADJUSTED UPWARD INTO THE UPPER 60S NORTHWEST TO NEAR 75 IN THE SOUTHEAST. ALSO ADJUSTED MIN TEMPS ON SATURDAY UPWARD TO ACCOUNT FOR THE CLOUDS AND MILD CONDITIONS AHEAD OF THE FRONT. MAX TEMPS ON SATURDAY WILL BE LIMITED GIVEN THE CLOUDS AND AREAS OF LIGHT RAIN BUT STILL EXPECT TEMPS TO REACH THE UPPER 50S NORTHWEST TO MID 60S SOUTHEAST. AT THIS POINT WE DON`T EXPECT ANY THUNDERSTORMS LATE FRIDAY INTO SATURDAY THUNDERSTORMS GIVEN THE MARGINAL MID LEVEL LAPSE RATES. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 1255 AM SUNDAY... MOSTLY VFR CONDITIONS WILL CONTINUE THROUGH THE 06Z VALID TAF PERIOD. AREAS OF MVFR CONDITIONS WILL OCCUR TOWARD KFAY AND KRWI THIS MORNING...WITH PATCHY MVFR CONDITIONS IN EITHER LOW CLOUDS OR LIGHT FOG TOWARD KRDU. MAINLY DURING THE AFTERNOON AND EVENING PATCHY LIGHT RAIN IS POSSIBLE SOUTH OF A LINE FROM ABOUT KFAY TO KRWI. THIS IS WHERE ANY THICKER CLOUDS SHOULD RESIDE DURING THAT TIME...THOUGH THEY ARE EXPECTED CURRENTLY TO HAVE A HIGHER PROBABILITY OF BEING VFR. WITH HIGH PRESSURE OVERHEAD...WINDS SHOULD BE SOMEWHAT VARIABLE. JUST ON THE WEST SIDE OF THE SURFACE RIDGE AXIS...WINDS SHOULD BE MORE SOUTHWEST TOWARD THE TRIAD. WINDS SHOULD TEND TO FAVOR NORTHERLY TOWARD KFAY. AT KRWI AND ESPECIALLY KRDU... THE LIGHT SURFACE WIND DIRECTION IS MORE CHALLENGING...LEANING WESTERLY DURING THE DAYLIGHT HOURS THOUGH IT COULD BE QUITE VARIABLE. BEYOND THE 06Z VALID TAF PERIOD...THE GREATEST PROBABILITY OF SUB- VFR CONDITIONS OVERNIGHT INTO MONDAY MORNING IN CLOUDS AND PATCHY LIGHT RAIN WILL BE ALONG AND EAST OF INTERSTATE 95...LEANING MVFR AS A CATEGORY...WITH A CHANCE OF SUB-VFR CONDITIONS IN LIGHT FOG TOWARD THE TRIAD. KRDU WILL BE IN BETWEEN...AND IT IS POSSIBLE FOR A PERIOD OF BOTH LIGHT FOG AND LOWER CLOUDS THERE BEFORE DRIER AIR AND SUBSIDENCE MOVING IN FROM THE WEST CREATE WIDESPREAD VFR CONDITIONS ACROSS CENTRAL NORTH CAROLINA BY LATE MONDAY AFTERNOON. MVFR CONDITIONS IN FOG ARE POSSIBLE LATE MONDAY NIGHT AND EARLY TUESDAY...THEN AS MOISTURE INCREASES...THERE IS A CHANCE OF SUB-VFR CONDITIONS IN LOW CLOUDS TUESDAY NIGHT INTO WEDNESDAY...WITH GREATER CHANCES OF THOSE CONDITIONS CURRENTLY TOWARD THE TRIAD THOUGH POSSIBLE THROUGHOUT CENTRAL NORTH CAROLINA PARTICULARLY WEDNESDAY NIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE && $$ SYNOPSIS...DJF NEAR TERM...DJF SHORT TERM...DJF LONG TERM...BLAES AVIATION...DJF
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
335 AM CST SUN DEC 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CST SUN DEC 1 2013 THE MAIN FOCUS IS ON THE INCREASING CHANCES FOR SNOW TONIGHT...MAINLY IN SOUTHEAST MINNESOTA...NORTHEAST IOWA AND FAR WESTERN WISCONSIN. CURRENTLY...NORTHWESTERLY FLOW ALOFT IS IN PLACE WITH A SURFACE RIDGE OF HIGH PRESSURE CENTERED ON THE EASTERN DAKOTAS. THE INITIAL QUESTION THIS MORNING IS WITH A STRATUS DECK THAT EXTENDS ACROSS NORTHERN WISCONSIN/MINNESOTA AND HOW FAR SOUTH IT WILL MAKE IT TODAY. THERE HAS NOT BEEN MUCH OF A SOUTHERLY PUSH WITH IT OVER THE PAST 6 HOURS OR SO...EXCEPT IN EASTERN WISCONSIN ALONG LAKE MICHIGAN. THE PAST FEW RUNS OF THE HRRR SHOW THIS STRATUS DECK HAVING TROUBLE MAKING IT SOUTH TODAY AS THE RIDGE OF HIGH PRESSURE COMES IN AND WEAKENS THE NORTHERLY SURFACE FLOW. IF THIS DECK DOES MAKE IT FURTHER SOUTH...IT WILL CAUSE TEMPERATURES TO BE ABOUT 5-10F COOLER FOR HIGHS. GOING INTO TONIGHT...A LEAD/WEAK MID LEVEL SHORT WAVE TROUGH WILL PROPAGATE EAST ACROSS THE NORTHERN PLAINS WHILE ISENTROPIC LIFT ON THE 290K SURFACE INCREASES. THIS SHOULD PROVIDE ENOUGH LIFT...ALBEIT WEAK...TO DEVELOP A BAND OF LIGHT SNOW FROM CENTRAL MINNESOTA DOWN ALONG THE MISSISSIPPI RIVER. ANY ACCUMULATIONS OVERNIGHT WILL BE ON THE LIGHT SIDE AT A FEW TENTHS OF AN INCH OR LESS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 335 AM CST SUN DEC 1 2013 LIFT AND MOISTURE WILL BECOME DEEPER MONDAY INTO WEDNESDAY AS THE CORE OF THE MID LEVEL TROUGH APPROACHES THE REGION. FOR MONDAY...THE MAIN FOCUS CONTINUES TO BE ALONG THE NOSE OF THE LOW LEVEL WARM AIR ADVECTION AND WHERE IT WILL SET UP. ALL OF THE 01.00Z GUIDANCE SHOW THE BAND OF PRECIPITATION EXPANDING THROUGH THE DAY AS THIS ADVECTION STRENGTHENS. HOWEVER...AS WARMER AIR COMES IN AT THE LOW LEVELS...SOME PRECIPITATION TYPE ISSUES ARISE WITH THE WARM LAYER POSSIBLY CAUSING THE SNOW TO CHANGE OVER TO RAIN. SURFACE TEMPERATURES SHOULD ALSO BE ON THE RISE ABOVE FREEZING...SO AM NOT EXPECTING ANY FREEZING RAIN AT THE MOMENT. THERE IS SOME UNCERTAINTY TOO WITH THE POSITION OF THE NORTHWEST TO SOUTHEAST SWATH OF PRECIPITATION WITH THE 01.00Z NAM/01.03Z SREF BEING THE FARTHEST NORTHEAST WHILE THE 01.00Z GFS/ECMWF DEVELOP IS MORE TO THE SOUTHWEST IN SOUTHEAST MINNESOTA/NORTHEAST IOWA. MAY BE UNDER-DOING THE SNOW AMOUNTS ON MONDAY...BUT THE POTENTIAL MIX HAS ME CAUTIOUS TO GO MUCH ABOVE A FEW TENTHS OF AN INCH. THE BIGGEST STORY WITH THE 01.00Z GUIDANCE IS HOW THEY HAVE ALL COME AROUND TO THIS THINKING OF A MUCH FASTER FRONTAL PASSAGE WITH THE DEEPENING SURFACE LOW/MID LEVEL TROUGH MOVING THROUGH EARLY ON WEDNESDAY. THE BEST CHANCES FOR ANY PRECIPITATION APPEARS TO BE FROM MONDAY NIGHT THROUGH WEDNESDAY AS THIS TROUGH APPROACHES. THE WARMER AIR COMING IN ON TUESDAY AHEAD OF THE SYSTEM SHOULD KEEP THE P-TYPE MAINLY AS RAIN UNTIL THE COLD FRONT COMES THROUGH EARLY ON WEDNESDAY. THE MAIN CHANCES FOR SNOW WILL BE ON MONDAY NIGHT AHEAD OF THE WARM AIR..AND THEN AGAIN ON WEDNESDAY MORNING BETWEEN THE LEAD COLD FRONT PASSAGE AND THE SECONDARY COLD FRONT WHICH USHERS IN THE DRASTICALLY COLDER AIR IN. OVERALL...CONFIDENCE IN GETTING ANY SPECIFIC DETAILS DOWN ON THE PRECIPITATION TRENDS IS PRETTY LOW...PARTICULARLY WITH THE SNOW AMOUNTS. IF ANY SNOW IS ABLE TO OCCUR WEDNESDAY MORNING AFTER THE FIRST FRONT COMES THROUGH...IT WILL MEAN THAT TEMPERATURES COULD BE COLDER THAN ADVERTISED GOING THROUGH THE REST OF THE WEEK. DUE TO THE FASTER FROPA...HAVE DROPPED THE PRECIPITATION CHANCES FROM THURSDAY INTO THE WEEKEND. AS FOR THE COLD SPELL...850MB TEMPERATURES ARE FORECAST TO DROP DOWN TO BETWEEN -15 TO -20C ON THURSDAY WITH THE POOL OF COLD AIR LASTING THROUGHOUT THE REGION PAST NEXT WEEKEND. EVEN IF THERE IS NO SNOW COVER DOWN ON THE GROUND...TEMPERATURES WILL BE MUCH BELOW NORMAL THROUGH THE FORESEEABLE FUTURE. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED AT 1115 PM CST SAT NOV 30 2013 BAND OF MID LEVEL CLOUDS CONTINUES TO HANG WEST-EAST ACROSS THE REGION...MOSTLY 8-12 KFT. HOWEVER...LARGE MVFR STRATUS DECK CONTINUES TO SINK SOUTHWARD FROM NORTHERN MN/LAKE SUPERIOR. RAP13 FAVORS KEEPING THIS CLOUD DECK TOGETHER...BUT IS ALSO TRENDING SLOWER WITH REACHING KRST/KLSE...MORE AFTER 15Z NOW. THE GFS/NAM NOT AS BULLISH ON BRINGING THE MVFR CLOUDS THIS FAR SOUTH...KEEPING MOST OF THEM TO THE NORTH AND EAST. MEANWHILE THE FOG/STRATUS SATELLITE IMAGERY SHOWS A LARGE AREA OF STRATUS...WITH CURRENT TIMING EVEN LATER THAN THE RAP...CLOSER TO 18Z. WILL CONTINUE TO HOLD WITH THE IDEA THAT THESE MVFR CIGS WILL MAKE IT TO THE KRST/KLSE...BUT WILL PUSH BACK THE TIMING. SOUNDINGS CONTINUE TO SUGGEST THAT THERE SHOULD BE ENOUGH MIXING FOR A DIURNAL INCREASE IN CIG HEIGHT BY 18Z...AND POTENTIALLY BECOME SCT AS DRY AIR MIXES IN. CLOUD FORECAST REMAINS TOUGH. TRENDS WILL HAVE TO BE MONITORED CLOSELY AND ADJUSTMENTS MADE AS NECESSARY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1039 PM MST SAT NOV 30 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 350 PM MST SAT NOV 30 2013 MAIN CONCERN THROUGH THE SHORT TERM WILL BE WIND SPEEDS... ESPECIALLY THROUGH THE HIGH WIND CORRIDORS. CONVERSE COUNTY HAS BEEN ADDED TO THE HIGH WIND WATCH...OTHERWISE NO CHANGES TO THE HAZARD GRIDS. TIMING OF WHEN WINDS WILL ACTUALLY START HITTING HIGH WIND CRITERIA IS SOMEWHAT IN QUESTION. ARLINGTON AND BORDEAUX COULD GET CLOSE LATE TONIGHT THROUGH ABOUT SUNRISE BUT IT LOOKS LIKE THE MAIN THREAT FOR STRONGER WINDS WILL HOLD OFF UNTIL MONDAY AFTERNOON WHEN A STRONG UPPER LEVEL JET PUSHES INTO SOUTHEAST WYOMING. GFS IS FASTER WITH THE ARRIVAL OF THE UPPER JET AND THUS FASTER RAMPING UP THE STRONG SURFACE WINDS AND THE GFS IS INDICATING STRONGER WINDS OVERALL. THE NAM IS A GOOD 6 HOURS SLOWER WITH THE ARRIVAL OF THE STRONGEST WINDS WHICH COULD BE DELAYED UNTIL AROUND 00Z MONDAY FOR WIND PRONE AREAS. REGARDLESS IT IS GOING TO BE VERY WINDY SUNDAY NIGHT AND CONTINUE INTO MONDAY WITH STRONG WINDS SPREADING EAST INTO THE PLAINS. WINTER STORM WATCH REMAINS IN EFFECT FOR THE SNOWY AND SIERRA MADRE RANGES. 18Z NAM HAS BACKED OFF THE QPF AMOUNTS OVER THE MOUNTAINS AND THE GFS IS BARELY GENERATING ANY QPF...OF COURSE THE MODELS TEND TO UNDER ESTIMATE QPF IN THIS TYPE OF FLOW REGIME. KEPT THE SNOW AMOUNTS AT THE HIGH END OF THE POTENTIAL RANGE FOR NOW...BUT IF THE NAM CONTINUE TO TREND DRIER...MAY NEED TO LOWER AMOUNTS. THE MAIN CONCERN IS THAT EVEN WITH LESSER SNOW AMOUNTS SUSTAINED WINDS WILL LIKELY HIT 50 MPH WITH HIGHER GUSTS PRODUCING BLOWING SNOW AND SIGNIFICANT REDUCTION IN VISIBILITIES. TOUGH CALL BETWEEN A HIGH WIND WARNING...WINTER STORM WARNING OR A WINTER WEATHER ADVISORY FOR THE MOUNTAINS...OF COURSE THE MAIN CHANCE FOR HIGH SNOW ACCUMULATIONS OVER THE MOUNTAINS WILL NOT OCCUR UNTIL TUESDAY AND WEDNESDAY. .LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 305 PM MST SAT NOV 30 2013 ARCTIC FRONT WILL SWEEP ACROSS THE CWA TUESDAY WITH GFS THE FASTEST SOLUTION...SOMEWHAT AN OUTLIER WITH MOST OTHER MODELS A BIT SLOWER. THIS WILL IMPACT MAX TEMPERATURES FOR TUESDAY AS TEMPERATURES WILL PLUNGE ONCE THE FRONT PASSES. MUCH COLDER TEMPERATURES EXPECTED FOR THE REST OF THE WEEK UNDER BROAD CYCLONIC UPPER FLOW. VERY COLD CONDITIONS FOR THURSDAY AND FRIDAY WHEN HIGHS MAY STRUGGLE TO REACH THE TEENS AS VERY LOW THICKNESSES PASS ACROSS THE REGION. PRECIPITATION-WISE...SNOW SHOULD BE ONGOING AT TIMES OVER THE HIGHER MTNS AND WEST DURING THE DAY TUESDAY THEN POST-FRONTAL LIGHT SNOWS SHOULD INCREASE OVER THE EASTERN PLAINS TUESDAY AFTERNOON AND NIGHT AS UPSLOPE FLOW DEEPENS AND MOISTURE INCREASES. SNOW SHOULD CONTINUE OVER MANY AREAS WEDS THEN TAPER OFF FROM NORTH TO SOUTH WEDS EVENING AS SFC HIGH BUILDS IN AND BETTER MOISTURE AND UPSLOPE FLOW SHIFTS SOUTH INTO COLORADO. COULD BE SOME PRETTY GOOD SNOWFALL AMOUNTS MAINLY OVER AND NEAR THE MTNS BUT VERY COLD AIRMASS SHOULD LIMIT ACCUMULATIONS SOME. MAINLY DRY CONDITIONS THEN EXPECTED BY LATE THURSDAY THROUGH SATURDAY OUTSIDE OF THE HIGHER MTNS WHERE SOME SNOW SHOWERS SHOULD RETURN BY THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY EVENING) ISSUED AT 1027 PM MST SAT NOV 30 2013 SCATTERED TO BROKEN MID LEVEL CLOUDS WILL PREVAIL TONIGHT...WITH MVFR TO IFR CIGS DEVELOPING OVER WESTERN AND SOUTHERN CARBON COUNTY BY DAYBREAK SUNDAY. NAM MOS AND HRRR HAVE BEEN CONSISTENT WITH AT LEAST IFR CIGS INVOF KRWL AND KSAA AIRFIELDS. KEPT PREVAILING BKN015 THROUGH SUNDAY AFTERNOON AT KRWL. SNOW SHOWERS WILL DEVELOP AND OBSCURE THE SNOWY AND SIERRA MTNS SUNDAY. IT WILL BE BREEZY TO WINDY SUNDAY WITH WESTERLY WINDS POSSIBLY GUSTING AS HIGH AS 50 KT FOR THE WIND CORRIDORS OF SOUTHEAST WY. GUSTS TO 35 KT ARE EXPECTED ELSEWHERE...EXCEPT 25 KT IN WESTERN NEBRASKA. && .FIRE WEATHER... ISSUED AT 325 AM MST SAT NOV 30 2013 WINDS TO REMAIN BREEZY TODAY AND TONIGHT WITH INCREASING WINDS THROUGH THE DAY SUNDAY INTO MONDAY. THEY COULD BECOME QUITE STRONG SUNDAY AFTERNOON THROUGH MONDAY AFTERNOON FOR AREAS ALONG AND WEST OF THE LARAMIE RANGE AND IMMEDIATELY TO THE EAST HERE NEAR CHEYENNE AND UP BY WHEATLAND. FORTUNATELY...WE ARE LOOKING AT AFTERNOON HUMIDITIES TO REMAIN IN THE 20S AND LOW 30S THROUGH MONDAY WITH FAIR TO EXCELLENT OVERNIGHT RECOVERIES. SNOW WILL BECOME WIDESPREAD NEXT WEEK FROM TUESDAY THROUGH THURSDAY. MOST LOCATIONS WILL SEE ACCUMULATING SNOWS AS A LOW PRESSURE SYSTEM TRACKS THROUGH THE AREA. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON FOR WYZ112-114. HIGH WIND WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON FOR WYZ106-110-116-117. HIGH WIND WATCH FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON FOR WYZ101-104-105-107-109-115-118. NE...NONE. && $$ SHORT TERM...LIEBL LONG TERM...RE AVIATION...JAMSKI FIRE WEATHER...LIEBL
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
951 AM EST SUN DEC 1 2013 .UPDATE... THE SHERIFF OFFICES AND THE OBSERVATIONS OVER THE INTERIOR AND WEST COAST METRO AREAS OF SOUTH FLORIDA ARE NOW REPORTING VISIBILITIES TO BE BETWEEN 1 TO 3 MILES IN THE FOG. SO WILL LET THE DENSE FOG ADVISORY EXPIRED AT 10 AM EDT THIS MORNING FOR THE INTERIOR AND WEST COAST METRO AREAS. THE FOG SHOULD CONTINUE TO BURN OFF THROUGH NOON TIME ALLOWING FOR THE SKIES TO BECOME PARTLY CLOUDY BY THIS AFTERNOON ALONG WITH DRY WEATHER. SO WILL SHOW A TREND OF CLEARING SKIES ALONG WITH DRY CONDITIONS FOR THE INTERIOR AND WEST COAST METRO AREAS. FOR THE EAST COAST METRO AREAS...THERE HAS BEEN SOME ISOLATED SHOWERS WORKING INTO THIS AREA FROM THE ATLANTIC WATERS. THE ISOLATED SHOWERS WILL CONTINUE TO WORK INTO THE EAST COAST METRO AREAS THROUGH THE AFTERNOON HOURS ON THE EASTERLY WIND FLOW. SO WILL KEEP A SLIGHT CHANCE OF SHOWERS IN PLACE FOR THE EAST COAST METRO AREAS THROUGH THIS AFTERNOON. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES ARE PLANNED. && .UPDATE...54/BNB .PREV DISCUSSION... /ISSUED 642 AM EST SUN DEC 1 2013/ AVIATION... REDUCED VSBYS IN FOG ARE MAINLY IMPACTING THE APF SITE THIS MORNING AND INLAND OF THE EAST COAST TERMINALS. THIS SHOULD BURN OFF BY OR BETWEEN 8-9AM WITH VFR CONDITIONS RETURNING. THE BEST CHANCE OF SHOWERS WILL BE ALONG THE EAST COAST TODAY...WHICH WILL BE CAPABLE OF PRODUCING PERIODS OF REDUCED CIGS/VSBYS THROUGH THE DAY. WINDS WILL REMAIN OUT OF THE NORTHEAST AND INCREASE TO AROUND 10 KT THROUGH THE LATE MORNING AND AFTERNOON HOURS. ALTHOUGH CONFIDENCE REMAINS TOO LOW...WINDS COULD SHIFT TO THE WNW AT APF DUE A GULF COAST SEA BREEZE THROUGH THE AFTERNOON PERIOD. WILL MONITOR THIS AND UPDATE IF NEEDED. && PREV DISCUSSION... /ISSUED 319 AM EST SUN DEC 1 2013/ DISCUSSION... HIGH PRESSURE TO THE NORTH CONTINUES TO BRING NORTHEASTERLY FLOW TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN TO WEAKEN TODAY, ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS STILL A FEW SHOWERS OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE NOT IMPACTING THE CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE FORECAST. THE HRRR DOES SHOW SOME ISOLATED SHOWERS OVER THE ATLANTIC COAST METRO AREAS THIS AFTERNOON, SO BROUGHT SLIGHT CHANCE POPS SOMEWHAT MORE WEST. MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING. EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS, COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER TODAY. AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE, ESPECIALLY IN THE OVERNIGHT HOURS. AVIATION... MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME. ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE DRAINAGE FLOW BEGINNING. MARINE... HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 79 63 77 61 / 20 10 10 - FORT LAUDERDALE 79 64 77 63 / 20 10 10 - MIAMI 80 65 78 63 / 20 10 10 - NAPLES 77 63 75 62 / - - 10 - && .MFL WATCHES/WARNINGS/ADVISORIES... FL...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR COASTAL COLLIER-GLADES-HENDRY-INLAND BROWARD-INLAND COLLIER-INLAND PALM BEACH. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...54/BNB AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS MIAMI FL
642 AM EST SUN DEC 1 2013 .AVIATION... REDUCED VSBYS IN FOG ARE MAINLY IMPACTING THE APF SITE THIS MORNING AND INLAND OF THE EAST COAST TERMINALS. THIS SHOULD BURN OFF BY OR BETWEEN 8-9AM WITH VFR CONDITIONS RETURNING. THE BEST CHANCE OF SHOWERS WILL BE ALONG THE EAST COAST TODAY...WHICH WILL BE CAPABLE OF PRODUCING PERIODS OF REDUCED CIGS/VSBYS THROUGH THE DAY. WINDS WILL REMAIN OUT OF THE NORTHEAST AND INCREASE TO AROUND 10 KT THROUGH THE LATE MORNING AND AFTERNOON HOURS. ALTHOUGH CONFIDENCE REMAINS TOO LOW...WINDS COULD SHIFT TO THE WNW AT APF DUE A GULF COAST SEA BREEZE THROUGH THE AFTERNOON PERIOD. WILL MONITOR THIS AND UPDATE IF NEEDED. && .PREV DISCUSSION... /ISSUED 319 AM EST SUN DEC 1 2013/ DISCUSSION... HIGH PRESSURE TO THE NORTH CONTINUES TO BRING NORTHEASTERLY FLOW TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN TO WEAKEN TODAY, ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS STILL A FEW SHOWERS OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE NOT IMPACTING THE CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE FORECAST. THE HRRR DOES SHOW SOME ISOLATED SHOWERS OVER THE ATLANTIC COAST METRO AREAS THIS AFTERNOON, SO BROUGHT SLIGHT CHANCE POPS SOMEWHAT MORE WEST. MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING. EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS, COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER TODAY. AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE, ESPECIALLY IN THE OVERNIGHT HOURS. AVIATION... MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME. ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE DRAINAGE FLOW BEGINNING. MARINE... HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 80 62 78 61 / 20 10 10 - FORT LAUDERDALE 80 64 78 63 / 20 10 10 - MIAMI 80 64 79 63 / 20 10 10 - NAPLES 78 63 76 62 / - - 10 - && .MFL WATCHES/WARNINGS/ADVISORIES... FL...DENSE FOG ADVISORY UNTIL 8 AM EST THIS MORNING FOR GLADES-HENDRY- INLAND BROWARD-INLAND COLLIER-INLAND PALM BEACH. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...54/BNB AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
804 AM CST SUN DEC 1 2013 .DISCUSSION... 302 AM CST TODAY... LOW PRESSURE IS SKIRTING EAST ACROSS THE CENTRAL GREAT LAKES WITH A TRAILING COLD FRONT SAGGING SOUTH ACROSS THE CENTRAL PART OF THE CWA EARLY THIS MORNING. A FEW RADAR RETURNS TO OUR NORTH MAINLY ASSOCIATED WITH MID LEVEL CLOUD COVER...AND PRECIP IS NOT MAKING ITS WAY TO THE SURFACE...NOR IS IT EXPECTED TO AS THE FRONT CONTINUES TO SLIP ACROSS THE CWA THROUGH THE MORNING. STRATUS DECK IS EVIDENT ON IR IMAGERY BUILDING SOUTH BEHIND THE FRONT. EXPECT THESE LOWER CLOUDS TO BUILD ACROSS THE FORECAST AREA LATER THIS MORNING THEN REMAIN IN PLACE THROUGH THE DAY AND TONIGHT. WEAK HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA TONIGHT...THOUGH MODEL RH FIELDS SHOW LITTLE IF ANY DISSIPATION OF THE STRATUS DECK. ASSUMING WE STAY CLOUDY OVERNIGHT...TEMPERATURES SHOULD STAY PROPPED UP INTO THE UPPER 20S TO LOW 30S DESPITE WINDS LIKELY GOING VERY LIGHT OR CALM. HOWEVER...IF WE DO SEE CLEARING...WILL HAVE TO MAKE HEFTY CHANGES TO OVERNIGHT LOWS WHICH COULD FALL 10+ DEGREES MORE THAN CURRENTLY FORECAST UNDER A STRONG RADIATIONAL COOLING SETUP. MONDAY... UPPER LOW DIGS FROM BRITISH COLUMBIA INTO THE PACIFIC NORTHWEST THIS PERIOD WHILE A LEAD WAVE KICKS EAST ACROSS THE NORTHERN PLAINS WITH SURFACE LOW UNDERGOING CYCLOGENESIS. ECMWF NO LONGER ADVERTISING SHORTWAVE EARLY MONDAY...WHICH IS IN LINE WITH OTHER MODEL SOLUTIONS THUS PULLED MENTION OF POPS MONDAY. BY MONDAY EVENING...H85 BAROCLINIC ZONE SETS UP FROM THE DAKOTAS INTO THE MID MISSISSIPPI VALLEY WITH A ZONE OF ISENTROPIC ASCENT FOCUSED JUST TO OUR WEST. STILL UNCERTAIN HOW FAR EAST THE PRECIP WILL EXTEND...BUT BEST CHANCES WILL BE IN THE NORTHWESTERN PORTIONS OF THE CWA AROUND ROCKFORD. PRECIP MAY START OFF AS RAIN SNOW MIX...BUT SHOULD TRANSITION TO ALL RAIN AS THE WARM AIR CONTINUES TO PUSH NORTHWARD. TEMPERATURES MAY RISE OVERNIGHT MONDAY NIGHT ACROSS PORTIONS IF NOT ALL OF THE CWA DEPENDING ON HOW QUICKLY THE WARM FRONT LIFTS ACROSS THE AREA. TUESDAY THROUGH WEDNESDAY... LONGWAVE TROUGH CONTINUES TO DEEPEN ACROSS THE WESTERN CONUS WITH DOWNSTREAM AMPLIFICATION OF THE RIDGE ACROSS THE CENTRAL CONUS. SURFACE LOW PROGGED TO TRACK FROM THE DAKOTAS INTO THE NORTHERN LAKES REGION THROUGH THE PERIOD WITH STRONG WARM ADVECTION AHEAD OF THE LOW WARMING H85 TEMPS TO AROUND 7-8C TUE/WED. 01/00Z EMCWF ACTUALLY THROWING A WRENCH INTO PREVIOUS FORECAST THINKING FOR THIS SYSTEM MIDWEEK...TRENDING MUCH FASTER AND MORE IN LINE WITH THE GFS. NOT QUITE READY TO BITE OFF ON THIS COMPLETELY AS OFTEN TIMES WITH CLOSED UPPER LOWS SLOWER MODEL SOLUTIONS TEND TO BE BETTER...AND WOULD NOT BE SURPRISED TO SEE THE GFS AND ECMWF TREND SLOWER IN THE NEXT COUPLE DAYS. TEMPERATURES ON WEDNESDAY A BIT TRICKY WITH BIG BUST POTENTIAL. SLIGHTLY FASTER OR SLOWER FROPA WILL RESULT IN A 15-20 DEGREE RANGE OF POSSIBLE TEMPERATURES. ECMWF CONTINUES TO BE AGGRESSIVE WITH TEMPERATURES AHEAD OF THE FRONT...SUGGESTING MID TO UPPER 50S ACROSS MUCH OF THE EASTERN HALF OF THE CWA EVEN WITH FASTER FROPA. THE GEM...WHICH IS SLOWER THAN THE GFS/ECMWF NOW SUGGESTING LOW TO MID 60S WEDNESDAY. TRENDED SLIGHTLY WARMER ACROSS THE EASTERN CWA WHICH WILL HAVE THE BEST LIKELIHOOD OF SEEING FULL WARMTH AHEAD OF THE FRONT. THURSDAY THROUGH SATURDAY... BY THURSDAY...H85 TEMPS SHOULD QUICKLY FALL TO AROUND -10C...THEN FURTHER COOL TO AROUND -15C TO -18C SATURDAY AS A COLD ARCTIC AIRMASS TRICKLES INTO THE REGION. BOTH THE GFS AND ECMWF INDICATE A SERIES OF WAVES LIFTING NORTHEAST ALONG THE FRONT CAUSING PRECIP NORTH OF THE FRONT AND POSSIBLY IMPACTING EASTERN PORTIONS OF THE CWA THURSDAY AND THURSDAY NIGHT. OTHERWISE...STRONG HIGH PRESSURE OVER THE NORTHERN PLAINS WILL BUILD SOUTHEAST WITH RIDGING IN PLACE FRIDAY INTO THE WEEKEND BRINGING MORE SETTLED AND COLD WEATHER...WITH HIGHS IN THE TEENS TO LOW 20S...AND SINGLE DIGIT LOWS FRIDAY AND SATURDAY. DEUBELBEISS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * MVFR CIGS THROUGH MID-DAY AND MAY LINGER INTO TONIGHT. JEE //DISCUSSION...UPDATED 12Z... COLD FRONT HAS JUST MOVED THROUGH TERMINALS EARLY THIS MORNING AND WILL CONTINUE TO TRACK OFF TO THE SOUTHEAST TODAY. LIGHT WINDS LESS THAN 10 KT INITIALLY SHIFTING NNW EXPECTED TO BECOME NORTH OR NE LATER THIS MORNING. WITH THIS SWITCH TO NNE WINDS...CONCERN BECOMES LARGE AREA OF MVFR STRATUS OVER NORTHERN LAKE MICHIGAN WHICH MODEL GUIDANCE CONTINUES TO INDICATE WILL MOVE INTO THE TERMINALS BY MID-DAY. CEILINGS UPSTREAM RANGE FROM 1500-3500 FT CURRENTLY...THOUGH AREA OF 2500 FT STRATUS ALONG THE EAST SHORE OF THE LAKE APPEARS TO BE BUILDING SOUTHWEST SIMILAR TO MODEL FORECASTS AND IS EXPECTED INTO ORD/MDW AREA 16-18Z. WEAK HIGH PRESSURE DEVELOPS ACROSS THE AREA TONIGHT...MAINTAINING LIGHT NNE WINDS. LACK OF STRONG SUBSIDENCE OR STRONGER LOW LEVEL WINDS RAISES QUESTION OF HOW LONG MVFR DECK WILL HANG AROUND. MODELS DIFFER IN THEIR SOLUTIONS WHICH LOWERS CONFIDENCE. HAVE MAINTAINED MVFR CIGS THROUGH THE NIGHT WHICH MAY BE ON THE PESSIMISTIC SIDE. ONCE SURFACE HIGH PASSES AND WINDS VEER SOUTHEAST MONDAY MORNING...IT DOES APPEAR THAT LOWER CLOUDS SHOULD SCATTER...WHILE VFR CLOUDS INCREASE. RATZER //ORD AND MDW CONFIDENCE...UPDATED 14Z... * MEDIUM-HIGH CONFIDENCE IN CIG TRENDS. * LOW CONFIDENCE IN HOW LONG MVFR...ESPECIALLY BKN014 CIGS...WILL LAST. * HIGH CONFIDENCE IN ALL OTHER FORECAST PARAMETERS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR PROBABLE. CHANCE OF -RASN. TUESDAY INTO WEDNESDAY...MVFR CIGS POSSIBLE. CHANCE OF RAIN ESPECIALLY WEDNESDAY. THURSDAY...SLGT CHANCE OF SHSN WITH MVFR VSBY. OTHERWISE MAINLY VFR. FRIDAY AND SATURDAY...MAINLY VFR. RATZER && .MARINE... 252 AM CST MAIN MARINE FORECAST CONCERNS FOCUS ON DEVELOPMENT OF STRONG LOW PRESSURE OVER THE PLAINS MONDAY-TUESDAY...WHICH THEN IS EXPECTED TO LIFT NORTHEAST ACROSS THE NORTHERN LAKES ON WEDNESDAY. THERE CONTINUES TO BE SOME SPREAD IN MODEL SOLUTIONS WITH THE DEPTH... TRACK AND TIMING OF THE LOW. WEAK LOW PRESSURE WAS OVER LOWER MICHIGAN STATE EARLY THIS MORNING...WITH A COLD FRONT TRAILING ACROSS SOUTHERN LAKE MICHIGAN. THE LOW WILL CONTINUE TO TRACK EAST ACROSS THE EASTERN LAKES THROUGH THIS EVENING...WITH THE FRONT PUSHING SOUTHEAST OF LAKE MICHIGAN LATER THIS MORNING. WEAK HIGH PRESSURE RIDGING WILL THEN MOVE ACROSS THE WESTERN LAKES LATER TODAY/TONIGHT...DRIFTING SLOWLY OFF TO THE EAST ON MONDAY. WITH A RELATIVELY WEAK PUSH TO THE FRONT TODAY... WINDS WILL SHIFT TO THE NORTH AT GENERALLY LESS THAN 15 KT. FORECAST MODELS CONTINUE TO DEPICT AN AREA OF LOW PRESSURE DEVELOPING ACROSS THE HIGH PLAINS BY EARLY MONDAY...WHICH THEN DEEPENS ACROSS THE CENTRAL PLAINS MONDAY NIGHT. VARIOUS MODEL SOLUTIONS CONTINUE TO SHOW DIFFERENCES WITH THE EVOLUTION OF THIS LOW THROUGH MID-WEEK...THOUGH THERE IS SOME CONSENSUS IN LIFTING THE LOW NORTHEAST ACROSS THE NORTHERN GREAT LAKES WEDNESDAY. GENERALLY HAVE CONTINUED TO FOLLOW THE SLOWER SOLUTIONS OF THE ECMWF/GEM/UKMET WITH THIS SYSTEM...THOUGH WILL HAVE TO SEE SOME OF THE DIFFERENCES IRONED OUT BEFORE CONFIDENCE INCREASES IN DETAILS OF STRENGTH/TRACK AND TIMING. IT DOES APPEAR THAT THE POTENTIAL EXISTS FOR SOUTHEAST 30-35 KT WINDS AHEAD OF THE LOW LATE TUESDAY INTO WEDNESDAY...AND WEST GALES LATER WEDNESDAY INTO THURSDAY WITH THE PASSAGE OF THIS STORM. STILL 3-4 DAYS OUT SO WILL NOT HAVE ANY HEADLINES...THOUGH WILL MENTION POSSIBLE GALES IN FORECAST FOR THIS PERIOD. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion National Weather Service Lincoln IL 542 AM CST Sun Dec 1 2013 .DISCUSSION... ISSUED 248 AM CST Sun Dec 1 2013 Main forecast challenge focuses on departing storm system for the middle and end of the week...and whether or not it will produce any wintry precipitation across central Illinois. SHORT TERM...Today through Tuesday Weak cold front currently across northern Illinois will sink southward today, eventually becoming stationary along the Ohio River by evening. Front will be accompanied by little in the way of sensible weather other than a shift in the wind. Low-level moisture seen on IR/fog satellite across southeast Missouri/far southern Illinois is progged by HRRR to remain mostly south of I-70 today, while patchy mid-level clouds over Iowa into far northern Illinois stay mostly north of the area. End result will be mostly sunny skies until later this afternoon when clouds begin to approach from the northwest. High temperatures will be bit cooler behind the cold front, ranging from the middle 40s far northwest around Galesburg to the lower 50s south of I-70. Boundary will remain in place along the Ohio River through Monday, before lifting back northward in response to rising upper-level heights Monday night into Tuesday. Models continue to show a subtle short-wave rippling eastward out of the Plains late Sunday night into Monday that could interact with the front to produce scattered light showers. Forecast soundings remain dry at low-levels: however, think forcing will be strong enough to mention a slight chance for showers on Monday. As front lifts northward, rain chances will shift into the southern Great Lakes on Tuesday. Brisk southerly winds south of the departing warm front will bring much warmer air into the region, with Tuesday afternoon highs reaching the lower to middle 50s. LONG TERM...Wednesday through Saturday Forecast becomes more challenging in the extended, as upper low currently over northwest British Columbia drops southward and carves a deep trough across the western CONUS by the middle of the week. Downstream ridging will place the Midwest/Great Lakes in a broad southwesterly flow pattern, leading to increased precip chances Wednesday into Thursday. Models have been struggling with the evolution of a surface low pressure system and its associated cold front for the past several runs: however, the 00z DEC 1 run seems to be coming into better agreement. While GFS remains a fast outlier, the latest ECMWF has sped up the front quite a bit. Following an ECMWF/GEM consensus yields FROPA across central Illinois on Wednesday followed by sharply colder conditions for the end of the week. Main question will be how much precip will hold back in the colder airmass Thursday and possibly Friday. Previous runs of the ECMWF had featured quite a bit of wintry precip Thursday night into Friday as a secondary wave of low pressure tracked along the departing front. While it still shows the potential for wintry precip, it has backed off/shifted E/SE with its latest solution. GEM seems to be the most consistent model over the past couple of days, so have trended toward its solution. With cold front passing on Wednesday, will mention a chance for showers. After FROPA, precip will largely shut off Wednesday night, before a wave of low pressure tracking from the lower Mississippi River Valley into the Ohio River Valley brings a renewed round of precip primarily across the eastern half of the KILX CWA on Thursday/Thursday night. Have focused highest POPs along/east of I-57 for both Thursday and Thursday night, tapering down to just slight chances further west along/west of the Illinois River. Precip type during the day Thursday will be rain across the east, with a rain/snow mix along I-55 and mostly light snow in the Illinois River Valley. As deeper layer of cold air arrives, precip will change to light snow across the board Thursday night, with a light accumulation possible. After that, will hold on to low chance POPs for snow across the far E/SE on Friday, although if trends continue, these may need to be dropped entirely. Main weather story for the end of the week will be the much colder conditions. Highs by Friday and Saturday will only be in the 20s, with overnight lows in the single digits and teens. && .AVIATION... ISSUED 535 AM CST Sun Dec 1 2013 Will see a few hours of MVFR vsbys in fog early this morning, then VFR conditions are expected into this evening, before another threat for some lower vsbys in fog late tonight. A weak cold front was pushing across the forecast area early this morning with winds ahead of the front light southwesterly, and light northwest to north winds were reported behind the boundary. forecast soundings and time-height cross sections indicate other than some sct-bkn cirrus at times today, not much in the way of significant cloud cover expected until this evening when a weak weather system well out to our west spreads clouds into our area. Cig heights look to be from 8000-1000 feet AGL later this evening. Due to the very light wind regime and despite the expected cloud cover tonight, we do expect some light fog to develop after 06z over most of the area with short range ensembles suggesting areas around I-74 seeing the higher probabilities for lower vsbys due to the fog. For now, will bring vsbys down to 4-5sm in br late tonight. Smith && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1005 AM EST SUN DEC 1 2013 .UPDATE... NEAR TERM FOR THE REST OF TODAY HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EST SUN DEC 1 2013 A WEAK COLD FRONT WILL MOVE INTO THE REGION FROM THE NORTH LATER TODAY...EVENTUALLY STALLING OUT NEAR THE OHIO RIVER EARLY MONDAY BEFORE RETURNING NORTH AS A WARM FRONT. CLOUDS WILL INCREASE TODAY AND TONIGHT...WITH A FEW RAIN SHOWERS DEVELOP ON MONDAY AS THE FRONT LIFTS BACK NORTH. STRONG LOW PRESSURE WILL TRACK INTO THE GREAT LAKES BY LATE WEDNESDAY...WITH A TRAILING COLD FRONT CROSSING THROUGH THE OHIO VALLEY INTO WEDNESDAY NIGHT AND THURSDAY AND BRINGING RAIN TO THE REGION. MUCH COLDER AIR WILL SPILL INTO CENTRAL INDIANA BEHIND THE FRONT...WITH THE POTENTIAL FOR PRECIPITATION TO END AS SNOW LATE WEEK. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1005 AM EST SUN DEC 1 2013 EXTENSIVE AREA OF STRATUS WAS ALONG AND SOUTH OF A VINCENNES TO GREENSBURG LINE WHILE MOSTLY CLEAR CONDITIONS WERE TO THE NORTH. HOWEVER AN AREA OF HIGH CLOUDS WAS SPREADING INTO OUR FAR NORTH. A WEAK AND DIFFUSE COLD FRONT WILL MOVE SOUTH ACROSS OUR REGION AND STALL OVER SOUTH CENTRAL SECTIONS BY THIS EVENING. THE MAIN CHANGES TO THIS FORECAST WILL BE TO REDUCE CLOUD COVER AS STRATUS TO OUR SOUTH HAS SHOWN NO PROGRESSION NORTHWARD AND RUC SOUNDINGS INDICATE THIS COULD BREAK UP LATER TODAY. EXPECT MOST AREAS NORTH AND CENTRAL TO START OUT MOSTLY SUNNY WITH PARTLY CLOUDY CONDITIONS ALL AREAS LATE TODAY. GIVEN THAT THERE WILL BE MORE SUNSHINE THAN PREVIOUSLY EXPECTED AND BASED ON RUC 2 METER TEMPERATURES...WILL RAISE HIGH TEMPERATURES TODAY ABOUT 3 DEGREES THAN WHAT PREVIOUSLY FORECASTED. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... ISSUED AT 329 AM EST SUN DEC 1 2013 FORECAST CHALLENGES FOCUS ON PRECIP CHANCES WITH THE BOUNDARY IN THE REGION LATE TONIGHT INTO EARLY TUESDAY. THE FRONT WILL BECOME NEARLY STATIONARY ACROSS THE REGION TONIGHT INTO EARLY MONDAY AS A BROADER WAVE ALOFT TRACKS OUT OF THE CENTRAL PLAINS AND INTO THE OHIO AND TENNESSEE VALLEYS BY MONDAY MORNING. MODEL SOUNDINGS INDICATING THE DEVELOPMENT OF A SHARP BUT SHALLOW INVERSION IN THE LOWEST 1-2KFT OVERNIGHT WITH THE LIKELIHOOD OF A LOW STRATUS DECK BECOMING WELL ESTABLISHED. HOWEVER WITH DRIER AIR PRESENT FURTHER UP THROUGH THE BOUNDARY LAYER...THINK THE MOIST LAYER WILL REMAIN TOO SHALLOW TO SUPPORT ANY PRECIP/DRIZZLE/SPRINKLES OVERNIGHT...AND HAVE REMOVED PRECIP CHANCES THROUGH DAYBREAK MONDAY. BEST CHANCE FOR A FEW RAIN SHOWERS LIKELY COMES MONDAY WITH SLIGHTLY BETTER FORCING ALOFT COURTESY OF THE AFOREMENTIONED UPPER WAVE AND PRESENCE OF DEEPER MOISTURE. LOWER LEVELS SHOULD WARM ENOUGH TO ALLOW PRECIP TO FALL AS ALL RAIN OVER FAR NORTHERN COUNTIES MONDAY MORNING. RAINFALL AMOUNTS WILL BE ONLY A FEW HUNDREDTHS AT BEST AND THE SPARSE NATURE OF THE RAIN SHOWERS WILL MEAN SOME LOCATIONS PROBABLY SEE NO PRECIP AT ALL. WILL MAINTAIN ONLY LOW CHANCE POPS INTO MONDAY EVENING. THE FRONT WILL LIFT NORTH OF THE REGION LATE MONDAY NIGHT IN RESPONSE TO LOW PRESSURE EJECTING OUT OF THE PACIFIC NORTHWEST AND INTO THE NORTHERN PLAINS BY TUESDAY MORNING. GUIDANCE CONTINUING TO VARY ON THE HANDLING OF THE SHARP POLAR VORTEX DIVING THROUGH THE NORTHERN ROCKIES AND THE OVERALL COMPLEX NATURE OF THE UPPER LEVEL FLOW. ONE TREND NOTED OVER THE LAST FEW MODEL RUNS HOWEVER IS A GENERAL CONSENSUS TOWARDS A FASTER EASTWARD PROGRESSION TO THE SURFACE WAVE AND ASSOCIATED COLD FRONT. THE OP GFS IS MOST PROGRESSIVE AND HAS SUPPORT FROM ITS ENSEMBLE MEMBERS...BUT APPEARS TO DAMPEN DOWNSTREAM UPPER RIDGING TOO QUICKLY. PREFER THE GROWING CONSENSUS PRESENTED BY THE OTHER MODELS WITH THE COLD FRONT QUICKLY APPROACHING THE MISSISSIPPI VALLEY BY WEDNESDAY MORNING. COULD SEE RAIN SHOWERS DEVELOP AS EARLY AS TUESDAY NIGHT AS A LOW LEVEL JET MOVES INTO THE OHIO VALLEY. TEMPS...UNDERCUT AGGRESSIVE MOS GUIDANCE OVERALL FOR MONDAY HIGHS WITH PRESENCE OF CLOUDS AND PRECIP LIKELY LIMITING WARMING. THE EXPANSION OF STRONG WARM ADVECTION SOUTH OF THE WARM FRONT ON TUESDAY SETTING THE STAGE FOR A MILD DAY EVEN DESPITE EXPECTED CLOUD COVER. MOS AGAIN LOOKED SOMEWHAT AGGRESSIVE...BUT A SEVERAL DEGREE BUMP IN TEMPS IS WARRANTED WITH THE ENTIRE AREA INTO THE MID/UPPER 50S. CLOSER TO THE WARMER MAVMOS TONIGHT WITH CLOUDS...THEN NEAR MOS FOR LOWS MONDAY/TUESDAY NIGHTS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... ISSUED AT 329 AM EST SUN DEC 1 2013 ENSEMBLES ARE IN GOOD AGREEMENT ON THE EVOLVING WEATHER PATTERN LATER THIS WEEK. MEAN UPPER TROUGHING EXPECTED FROM THE NORTHERN PLAINS BACK INTO THE SOUTHWEST...WHILE UPPER RIDGING DEVELOPS OVER THE SOUTHEAST. THIS WILL RESULT IN SOUTHWESTERLY UPPER FLOW LOCALLY. APPEARS A DECENT CHUNK OF ENERGY WILL EJECT OUT OF THE WESTERN TROUGH INTO WESTERN GREAT LAKES AROUND WEDNESDAY. WILL KEEP SOME RAIN CHANCES IN THE FORECAST FOR WEDNESDAY AS THE UPPER DISTURBANCE MOVES THROUGH. AFTER THAT...FORECAST BECOMES MORE MUDDLED AS THE POTENTIAL EXISTS FOR WAVES TO EJECT OUT OF THE WESTERN TROUGH. AT THIS POINT...THE ENSEMBLES DON/T INDICATE ANY MAJOR LOW PRESSURE SYSTEMS...BUT RATHER STABLE TYPE SURFACE WAVES RIPPLING ALONG A PRIMARY FRONTAL ZONE LOCATED OVER THE TENNESSEE VALLEY. ENSEMBLES SEEM TO KEY IN ON ONE WAVE MOVING THROUGH AROUND THURSDAY INTO EARLY FRIDAY...AND ANOTHER JUST AFTER THIS FORECAST PERIOD. ALTHOUGH AN ARGUMENT CAN BE MADE FOR AT LEAST SOME PRECIPITATION THREAT EVERY DAY...FOR NOW WILL KEEP THE POPS RESTRICTED TO THURSDAY AND FRIDAY. APPEARS THERE IS POTENTIAL FOR SOME LIGHT SNOW ACCUMULATIONS THURSDAY NIGHT INTO FRIDAY MORNING. && .AVIATION /DISCUSSION FOR THE 011500Z TAF UPDATE/... ISSUED AT 921 AM EST SUN DEC 1 2013 KIND TAF IS GOOD. ONLY MINOR TWEAKS MADE. LOOKS LIKE KIND WILL REMAIN IN BETWEEN BKN050 DECK TO THE SOUTHEAST AND BKN150 DECK TO THE NORTHWEST INTO THE AFTERNOON. PREVIOUS DISCUSSION FOLLOWS... VFR CEILINGS AROUND 050 CURRENTLY IN THE KBMG AREA SHOULD SCATTER OUT BY ISSUANCE TIME. OTHERWISE...WEAK FRONTAL SYSTEM EXPECTED TO DROP SOUTHEAST ACROSS THE TAF SITES IN THE 011800Z-020000Z TIME FRAME...ACCOMPANIED BY A GRADUAL WIND SHIFT TO 320-350 DEGREES. WIND SPEEDS SHOULD GENERALLY REMAIN UNDER 10 KTS ACROSS THE FRONT. FRONT SHOULD BE INACTIVE FOR THE MOST PART...OTHER THAN THE FACT THAT IT WILL HELP PULL DOWN SOME OF THE MVFR CEILINGS AROUND 025 CURRENTLY OVER THE GREAT LAKES LATER THIS AFTERNOON AND EARLY THIS EVENING. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...JH SHORT TERM...RYAN LONG TERM....JAS AVIATION...JAS/50 VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS GRAY ME
956 AM EST SUN DEC 1 2013 .SYNOPSIS... WEAK LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA THROUGH TONIGHT. A SECOND WEAK LOW WILL TRACK NORTHEAST AND PASS JUST OFFSHORE TONIGHT AND EARLY MONDAY. THESE TWO SYSTEMS WILL PRODUCE SOME OCCASIONAL LIGHT SNOW INTO TONIGHT, WITH MIXING OR A CHANGEOVER TO LIGHT RAIN POSSIBLE NEAR THE COAST. WEAK TROUGHING ALONG THE COAST KEEPS PRECIPITATION NEARBY ON MONDAY. LOW PRESSURE TRAVELS UP THE ATLANTIC COASTLINE TUESDAY, SPREADING MORE PRECIPITATION OVER THE REGION THROUGH WEDNESDAY MORNING. RIDGING BUILDS IN BRIEFLY BEFORE A COLD FRONT CROSSES THE REGION THURSDAY. && .NEAR TERM /UNTIL 5 PM THIS AFTERNOON/... 945 AM...THE COASTAL FRONT IS SETTING UP SHOP JUST OFFSHORE THEN EXTENDS INTO MY EASTERN ZONES AND TO THE WEST OF ROCKLAND. I LOWERED MAXIMUM TEMPERATURES A BIT IN MANY AREAS AS A RESULT. MODELS HAVE A WEAK LOW TRAVELING NORTHEAST ALONG THIS BOUNDARY LATE TODAY AND TONIGHT WITH HEAVIEST QPF FOR MID COAST REGION. WHILE AREAS NEAR ROCKLAND MAY STAY ON THE WARM SIDE OF THE BOUNDARY AND SEE MAINLY RAIN...IMMEDIATELY ON THE OTHER SIDE OF THE BOUNDARY SEVERAL INCHES OF WET SNOW WILL FALL. I MADE ADJUSTMENTS TO 1ST PERIOD GRIDS BASED ON THE MESONET AND TO REFLECT THE LATEST RADAR TRENDS FOR BANDED PRECIPITATION. ON THE WATERS...WINDS AND SEAS TOUCHED MARGINAL SMALL CRAFT ALONG THE BOUNDARY AND I`VE ISSUED AN SCA FOR AREA OUTSIDE THE BAY FOR THE NEXT FEW HOURS. HRR WINDS WERE USED TO TAILOR WIND GRIDS TO BETTER REFLECT THE COASTAL BOUNDARY. PREV DISC... 640 AM...FORECAST THINKING GENERALLY ON TRACK. ACTUALLY MODELS SEEM TO HAVE A DECENT HANDLE ON THE CURRENT EVENTS...WITH 06Z NAM12 HANDLING THE LARGER SCALE WELL...CAPTURING THE SHRA DEVELOPING OVER CT AND LONG ISLAND SOUND...AND THE RUC PICKING UP ON THE VERY LIGHT SHSN /MAYBE SNIZZLE?/...OVER THE COASTAL PLAIN....WHERE THIS SHOULD REMAIN SPOTTY THRU THE MORNING...AND CHANGE TO RA ON THE COAST....BEFORE STEADIER PRECIP DEVELOPS THIS AFTERNOON. ANY CHANGES TO THE FORECAST BASED ON CURRENT OBS HAVE BEEN MINOR AND ONLY RUN THRU APPROX THE FIRST 6 HOURS OF THE FORECAST. PREVIOUSLY...A SOMEWHAT TRICKY FORECAST TODAY INTO TONIGHT AS VERY WEAK IMPULSES ALOFT...ONE TO OUR S AND ONE TO OUR N PASS THROUGH WITHIN LESS THAN 12 HOURS OF EACH OTHER...ALTHOUGH EITHER ONE IS VERY DYNAMIC. THE FIST ONE...IN THE SRN STREAM ACTUALLY MOVES THROUGH IN THE NEXT FEW HOURS...WITH VERY WEAK SFC REFLECTION...AND LIGHT PRECIP ASSOCIATED WITH WEAK WAA AHEAD OF IT MOVED THRU OVERNIGHT. THE SECOND APPROACHES TODAY...AND GENERATES A BIT MORE LOW TO MID-LVL WAA...WHICH WORKS WITH COASTAL FRONT...AND GENERATES AN INVERTED SFC TROUGH. THIS PRODUCES SOME MORE ORGANIZED FORCING ALONG AND JUST INLAND FROM THE COAST THIS AFTERNOON. WHILE SOME LIGHT PRECIP IS POSSIBLE THIS MORNING...THE BETTER CHC WILL BE THIS AFTERNOON INTO THE EVENING AS THE FORCING INCREASES. THIS PRECIP WILL NOT MOVE IN FROM THE WEST SO MUCH AS IT DEVELOPS ALONG THE COASTAL FRONT. COASTAL AREAS...FIRST TIER OF COASTAL ZONES...ARE LIKELY TO START AS RAIN OR SHIFT TO RAIN QUICKLY...BUT P-TYPE WILL BE SOMEWHAT OF AN ISSUE FOR INLAND AREAS OF THE COASTAL PLAIN. THE COASTAL FRONT WILL MOVE INLAND TODAY...SO SOME AREAS THAT SEE SOME LIGHT SNOW EARLY WILL CHANGE TO RAIN THIS AFTERNOON...AND MOST PLACES IN NH AND FAR WRN ME WILL BE LIMITED TO ABOUT A TENTH OF TOTAL QPF ANYWAY...WHICH WILL LIMIT TO SNOWFALL TO AN INCH OR SO...MAYBE A LITTLE MORE IN THE MTNS...WHERE RATIOS WILL BE HIGHER. MODELS SEEM TO BE FAIR AGREEMENT WHERE HIGHEST QPF WILL OCCUR...MAINLY E OF KPWM-KLEW...WHERE QPF TODAY INTO THIS EVE LOOKS BE 0.3-0.4 INCHES. SO INLAND AREAS OF THE KENNEBEC AND PENOBSCOT VLYS ARE WHERE THE MOST SNOW IS EXPECTED TO FALL. HERE WE ARE LOOKING AT GENERALLY ONE TO THREE INCHES...WITH SOME 4 INCH AMOUNTS POSSIBLE. THE BULLSEYE FOR THE HIGHEST SNOWFALL LOOKS TO BE IN THE SKOWHEGAN-WATERVILLE-UNITY VICINITY. HOWEVER...MODELS ARE FAR FROM PERFECT WHEN IT COMES TO INVERTED TROUGHS...AND THIS COULD END UP SHIFTING A BIT. && .SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM MONDAY/... AS THE WEAK 500MB TROUGH ACTUALLY DEEPENS SLIGHTLY JUST TO OUR E LATE TONIGHT...EXPECTING SOME WEAK RIDGING ALOFT TO DEVELOP BEHIND IT FOR MONDAY. WILL LOSE A FEW DEGREES AS WINDS SHIFT N ON THE BACK END OF THE TROUGH...ESPECIALLY IN THE N...AND THIS COULD TURN BACK TO LIGHT SN BEFORE IT ENDS IN ERN ZONES. SO PRECIP IS EXPECTED TO WIND DOWN LATE TONIGHT...WITH A BREAK EXPECTED ON MONDAY...ALTHOUGH WE PROBABLY WILL NOT SEE MUCH SUN ON MONDAY...AS STAGNANT LOW LVL FLOW LINGERS. HIGHS SHOULD CLIMB BACK INTO THE MID 30S TO AROUND 40 AGAIN. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS WAS THE CASE THE LAST COUPLE OF NIGHTS...NWP CONTINUES TO INDICATE SRN STREAM S/WV TROF WILL OUTPACE ITS NRN STREAM COUNTERPART. THE RESULT IS LOW PRES DEVELOPING OFF THE SOUTHEAST COASTLINE...AND HEADING OUT TO SEA WITH A LATE CAPTURE THAT SWINGS IT TOWARDS THE CANADIAN MARITIMES. CONSENSUS IS THAT PCPN WILL ONLY BRUSH THE COAST...WITH THE MIDCOAST PERHAPS SEEING A LITTLE LONGER DURATION AS LOW PRES CUTS ACROSS BAROCLINIC ZONE. MODEL GUIDANCE HAS A VERY SHARP NRN EDGE TO THE SATURATED SNOW GROWTH ZONE...SO WE WILL BE TREADING A VERY FINE LINE OF SN OR NO SN HEADING INTO TUE. IN FACT...SFC TEMPS WILL BE MARGINAL ENOUGH THAT SOME RNFL IS POSSIBLE NEAR THE COAST. AS UPPER TROF CROSSES THE AREA THERE SHOULD BE ENOUGH FORCING AND RESIDUAL MOISTURE TO BRING SCT SHSN TO MUCH OF THE AREA BEFORE HIGH PRES BUILDS IN AND ENDS PCPN. THAT RIDGING WILL BE SHORT LIVED THOUGH...AS NEXT LOW PRES DEVELOPS AND LIFTS INTO CANADA. THIS WILL DRIVE A COLD FNT TOWARDS NEW ENGLAND. AFTER INITIAL BURST OF WAA AHEAD OF THE LOW PRES...COLD WILL SLOWLY OOZE INTO THE AREA AS FNT BECOMES ALIGNED WITH FLOW ALOFT. AS LONG AS BOUNDARY REMAINS IN THE AREA IT WILL BE HARD TO RULE OUT OVERRUNNING PCPN IN BROAD SWLY WAA REGIME. LATE IN THE WEEK STRONG HIGH PRES WILL BUILD INTO THE REGION...BEFORE WRN TROF EJECTS NEWD. GIVEN LOCATION OF HIGH PRES...IT WOULD NOT BE SURPRISING TO SEE NWP TREND COOLER WITH TIME...THOUGH THERE ARE SEVERAL DAYS BEFORE ANY DETAILS WILL BECOME MORE CLEAR. && .AVIATION /15Z SUNDAY THROUGH THURSDAY/... SHORT TERM...SHOULD SEE ALL TERMINALS GET A PERIOD OF MVFR TO IFR TODAY WITH SHSN INLAND...AND SHRA ON THE COAST. A STEADIER RA IS EXPECTED AT KRKD...AND A STEADY MIX OF RASN AT KAUG. CONDITIONS WILL IMPROVE LATE TONIGHT TO VFR FROM KPWM WWD...AND EVENTUALLY AT KAUG/KRKD ON MONDAY. LONG TERM...AREAS OF MVFR OR LOWER CONDITIONS WILL BE POSSIBLE TUE INTO WED AS OCEAN LOW PRES PASS OUT TO SEA. COASTAL TERMINALS WILL SEE LOWER CIGS AS WELL AS POSSIBLE SHSN LIMITING VSBYS. PASSAGE OF UPPER TROF MAY ALSO RESULT IN SOME MTNS SHWRS INVOF OF KHIE. && .MARINE... SHORT TERM...SOUTHERLY SURGE IN WINDS OCCURRING ATTM AND COULD SEE A FEW GUSTS UP TO 25 KT THRU SUNRISE. OTHERWISE...QUIET WEATHER WITH VSBY RESTRICTIONS EXPECTED LATER TONIGHT THROUGH SUNDAY NIGHT IN DEVELOPING RAIN AND SNOW. LONG TERM...STILL SOME UNCERTAINTY REGARDING THE TRACK OF COASTAL LOW PRES MIDWEEK. HOWEVER CONFIDENCE IS GROWING THAT SEAS WILL BUILD TO AT OR ABOVE 5 FT FOR TUE AND WED. WINDS MORE THAN LIKELY SHOULD REMAIN AT OR BELOW 25 KTS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ANZ150- 152-154. && $$ SCHWIBS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
915 AM EST SUN DEC 1 2013 .SYNOPSIS... LOW PRESSURE IS EXPECTED TO CROSS THE STATE TODAY AND REDEVELOP IN THE GULF OF MAINE TONIGHT, PASSING WELL E OF THE REGION ON MONDAY. ANOTHER LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE MIDDLE PART OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 915 AM UPDATE...NO SIGNIFICANT CHANGES WERE NEEDED WITH THIS UPDATE. MADE SOME SLIGHT ADJUSTMENTS TO POPS THROUGH THIS AFTERNOON TO MATCH CURRENT RADAR TRENDS AND THE LATEST GUIDANCE. ALSO BUMPED UP TEMPS JUST A BIT ALONG THE COAST, WHERE IT`S ALREADY IN THE MID 30S. OTHERWISE, NO OTHER CHANGES WERE NEEDED. PREVIOUS DISCUSSION...WEAK LOW PRES MOVING ACROSS THE EASTERN GREAT LAKES IS FCST TO MOVE ACROSS SOUTHERN NEW ENGLAND THIS AFTERNOON AND THEN INTO THE GULF OF MAINE. THE CONCERN IS WHERE TO DRAW THE RAIN/SNOW LINE AS WAA MAKES ITS WAY TO THE BLYR. TEMPERATURES ARE FCST TO REACH INTO THE UPPER 20S TO AROUND 30 ACROSS THE NORTHERN 1/2 OF THE CWA WHILE LOW TO MID 30S ARE EXPECTED FOR CENTRAL AND DOWNEAST AREAS. AN INVERTED TROF EXTENDING FROM THE LOW COMBINED W/SOME FRONTOGENETICAL FORCING AT 1000-700MB WILL LEAD TO A REFORMATION OF PRECIP AND AN ENHANCEMENT OF THE PRECIP. USING THE BUFKIT PROFILES AND SOUNDINGS, THINKING HERE IS THAT SNOW WILL REDEVELOP ACROSS PORTION OF NORTHEAST MAINE W/THE HEAVIEST AXIS ACROSS THE HOULTON AND DANFORTH REGION W/LESS SNOW NORTH AND WEST. S OF OF THE HOULTON-DANFORTH LINE, TEMPERATURES WILL WARM INTO THE MID 30S TO ALLOW FOR SNOW TO MIX WITH AND CHANGEOVER TO RAIN. THIS IN TURN WILL CUT DOWN ON SNOWFALL LATER THIS AFTERNOON INTO TONIGHT. DECISION WAS TO GO AHEAD AND ADD NORTHERN PENOBSCOT AND SE AROOSTOOK COUNTY IN THE WINTER WEATHER ADVISORY THROUGH MONDAY MORNING DUE TO ENHANCED FRONTOGENTICAL FORCING LEADING TO HEAVY SNOW BURSTS. LATEST SNOW TOTAL MAP SHOWS A GENERAL 4-8 INCHES IN THE ADVISORY AREA W/1-4 INCHES N AND W. THE COAST AND EXTREME EASTERN WASHINGTON COUNTY FROM MEDDYBEMPS TO EASTPORT WILL SEE 0.30 TO 0.70 INCHES OF RAINFALL AFTER SOME INITIAL SNOWFALL. SNOW WILL CONTINUE INTO TONIGHT ACROSS THE NORTHEASTERN SECTION OF MAINE INCLUDING CARIBOU-PRESQUE ISLE DOWN THROUGH DANFORTH. WEST OF THIS AREA, LITTLE OR NO SNOW AND RAIN/SNOW S OF THIS AREA W/RAIN FOR THE COAST AS THE WARM AIR IS FCST TO STAY IN. TEMPERATURES WILL DROP BACK INTO THE UPPER TEENS AND LOWER 20S NORTH AND WEST AND MID TO UPPER 20S FOR CENTRAL AREAS. LOW 30S FOR THE DOWNEAST REGION INCLUDING THE COAST. && .SHORT TERM /MONDAY THROUGH TUESDAY/... SNOW WILL CONTINUE TO WIND DOWN EARLY MONDAY AS THE INVERTED TROF EXTENDING FROM THE CANADIAN MARITIMES THROUGH DOWNEAST MAINE MOVES OFF TO THE NORTHEAST. THERE MAY STILL BE SOME LINGERING LIGHT SNOW OR SNOW SHOWERS PARTICULARLY ACROSS EASTERN AREAS OTHERWISE EXPECT MOSTLY CLOUDY SKIES ACROSS THE REGION. MONDAY NIGHT WILL BE MOSTLY CLOUDY BUT DRY AS WEAK HIGH PRESSURE RIDGES DOWN FROM THE NORTH. ATTENTION THEN TURNS TO ANOTHER LOW PRESSURE SYSTEM THAT WILL BE MOVING NORTHEAST ACROSS THE WESTERN ATLANTIC. THIS SYSTEM MAY BRINGS SOME PRECIPITATION TO THE REGION LATER TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... MODELS SEEM TO BE COMING INTO BETTER AGREEMENT FOR THE NEXT SYSTEM TUESDAY NIGHT AND WEDNESDAY. STILL SOME MODEL DIFFERENCES BUT THE CONSENSUS SOLUTION IS FOR THE LOW TO TRACK FAR ENOUGH EAST THAT ANY IMPACTS IN OUR REGION WOULD BE ACROSS DOWNEAST/EASTERN MAINE. A WEAK BOUNDARY WILL CROSS THE REGION BY LATE WEEK WITH SOME SNOW/RAIN SHOWERS POSSIBLE. AGAIN...WILL STICK CLOSE TO THE SUPERBLEND. HIGH PRESSURE WILL BUILD EAST TOWARD THE REGION BY SATURDAY. && .AVIATION /14Z SUNDAY THROUGH THURSDAY/... NEAR TERM: MVFR W/PERIODS OF VFR THIS MORNING DROPPING TO MVFR AND EVEN IFR LATER THIS MORNING ON INTO TONIGHT. SNOW ACROSS THE NORTHERN TERMINALS W/SNOW TO RAIN FOR KBGR TO KBHB. SHORT TERM: MVFR CONDS ARE POSSIBLE EARLY MONDAY THEN VFR CONDS EXPECTED MONDAY NIGHT INTO TUESDAY. MVFR CONDS ARE POSSIBLE IN SOME LIGHT PRECIP LATE TUESDAY AND INTO EARLY WEDNESDAY. VFR ON THURSDAY. && .MARINE... NEAR TERM: DECIDED TO GO W/A SCA THROUGH LATE MORNING. WINDS GUSTING TO 25 KTS AS LLVL JET OF 30 KT MOVES ACROSS THE WATERS. THE GFS AND NAM AS WELL AS THE LATEST RAP MODEL PICK UP ON THIS FEATURE. WINDS ARE FCST TO DROP OFF THIS AFTERNOON AS THE LLVL JET SHIFTS TO THE E. SEAS ARE AT 5FT AND COULD TIP 6 FT ESPECIALLY AT 44027(JONESPORT) THIS MORNING. SEAS WILL GRADUALLY SUBSIDE TONIGHT BELOW 4 FT. SHORT TERM: WINDS/SEAS WILL BE BELOW SCA LEVELS MON AND MON NIGHT. WIND/SEAS MAY INCREASE TO SCA LEVELS TUE/TUE NIGHT. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ005-006- 011-016-017-032. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR ANZ050>052. && $$ NEAR TERM...HASTINGS/HEWITT SHORT TERM...DUDA LONG TERM...DUDA AVIATION...HASTINGS/HEWITT/DUDA MARINE...HASTINGS/HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS GRAY ME
817 AM EST SUN DEC 1 2013 .SYNOPSIS... WEAK LOW PRESSURE WILL TRACK SOUTHEAST OUT OF QUEBEC AND ACROSS THE AREA TONIGHT...PRODUCING SOME LIGHT SNOW INLAND AND A MIX OF SNOW AND RAIN NEAR THE COAST. WEAK TROUGHING ALONG THE COAST KEEPS PRECIPITATION NEARBY ON MONDAY. LOW PRESSURE TRAVELS UP THE ATLANTIC COASTLINE TUESDAY...SPREADING MORE PRECIPITATION OVER THE REGION THROUGH WEDNESDAY MORNING. RIDGING BUILDS IN BRIEFLY BEFORE A COLD FRONT CROSSES THE REGION THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 640 AM...FORECAST THINKING GENERALLY ON TRACK. ACTUALLY MODELS SEEM TO HAVE A DECENT HANDLE ON THE CURRENT EVENTS...WITH 06Z NAM12 HANDLING THE LARGER SCALE WELL...CAPTURING THE SHRA DEVELOPING OVER CT AND LONG ISLAND SOUND...AND THE RUC PICKING UP ON THE VERY LIGHT SHSN /MAYBE SNIZZLE?/...OVER THE COASTAL PLAIN....WHERE THIS SHOULD REMAIN SPOTTY THRU THE MORNING...AND CHANGE TO RA ON THE COAST....BEFORE STEADIER PRECIP DEVELOPS THIS AFTERNOON. ANY CHANGES TO THE FORECAST BASED ON CURRENT OBS HAVE BEEN MINOR AND ONLY RUN THRU APPROX THE FIRST 6 HOURS OF THE FORECAST. PREVIOUSLY...A SOMEWHAT TRICKY FORECAST TODAY INTO TONIGHT AS VERY WEAK IMPULSES ALOFT...ONE TO OUR S AND ONE TO OUR N PASS THROUGH WITHIN LESS THAN 12 HOURS OF EACH OTHER...ALTHOUGH EITHER ONE IS VERY DYNAMIC. THE FIST ONE...IN THE SRN STREAM ACTUALLY MOVES THROUGH IN THE NEXT FEW HOURS...WITH VERY WEAK SFC REFLECTION...AND LIGHT PRECIP ASSOCIATED WITH WEAK WAA AHEAD OF IT MOVED THRU OVERNIGHT. THE SECOND APPROACHES TODAY...AND GENERATES A BIT MORE LOW TO MID-LVL WAA...WHICH WORKS WITH COASTAL FRONT...AND GENERATES AN INVERTED SFC TROUGH. THIS PRODUCES SOME MORE ORGANIZED FORCING ALONG AND JUST INLAND FROM THE COAST THIS AFTERNOON. WHILE SOME LIGHT PRECIP IS POSSIBLE THIS MORNING...THE BETTER CHC WILL BE THIS AFTERNOON INTO THE EVENING AS THE FORCING INCREASES. THIS PRECIP WILL NOT MOVE IN FROM THE WEST SO MUCH AS IT DEVELOPS ALONG THE COASTAL FRONT. COASTAL AREAS...FIRST TIER OF COASTAL ZONES...ARE LIKELY TO START AS RAIN OR SHIFT TO RAIN QUICKLY...BUT P-TYPE WILL BE SOMEWHAT OF AN ISSUE FOR INLAND AREAS OF THE COASTAL PLAIN. THE COASTAL FRONT WILL MOVE INLAND TODAY...SO SOME AREAS THAT SEE SOME LIGHT SNOW EARLY WILL CHANGE TO RAIN THIS AFTERNOON...AND MOST PLACES IN NH AND FAR WRN ME WILL BE LIMITED TO ABOUT A TENTH OF TOTAL QPF ANYWAY...WHICH WILL LIMIT TO SNOWFALL TO AN INCH OR SO...MAYBE A LITTLE MORE IN THE MTNS...WHERE RATIOS WILL BE HIGHER. MODELS SEEM TO BE FAIR AGREEMENT WHERE HIGHEST QPF WILL OCCUR...MAINLY E OF KPWM-KLEW...WHERE QPF TODAY INTO THIS EVE LOOKS BE 0.3-0.4 INCHES. SO INLAND AREAS OF THE KENNEBEC AND PENOBSCOT VLYS ARE WHERE THE MOST SNOW IS EXPECTED TO FALL. HERE WE ARE LOOKING AT GENERALLY ONE TO THREE INCHES...WITH SOME 4 INCH AMOUNTS POSSIBLE. THE BULLSEYE FOR THE HIGHEST SNOWFALL LOOKS TO BE IN THE SKOWHEGAN-WATERVILLE-UNITY VICINITY. HOWEVER...MODELS ARE FAR FROM PERFECT WHEN IT COMES TO INVERTED TROUGHS...AND THIS COULD END UP SHIFTING A BIT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...AS THE WEAK 500MB TROUGH ACTUALLY DEEPENS SLIGHTLY JUST TO OUR E LATE TONIGHT...EXPECTING SOME WEAK RIDGING ALOFT TO DEVELOP BEHIND IT FOR MONDAY. WILL LOSE A FEW DEGREES AS WINDS SHIFT N ON THE BACK END OF THE TROUGH...ESPECIALLY IN THE N...AND THIS COULD TURN BACK TO LIGHT SN BEFORE IT ENDS IN ERN ZONES. SO PRECIP IS EXPECTED TO WIND DOWN LATE TONIGHT...WITH A BREAK EXPECTED ON MONDAY...ALTHOUGH WE PROBABLY WILL NOT SEE MUCH SUN ON MONDAY...AS STAGNANT LOW LVL FLOW LINGERS. HIGHS SHOULD CLIMB BACK INTO THE MID 30S TO AROUND 40 AGAIN. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS WAS THE CASE THE LAST COUPLE OF NIGHTS...NWP CONTINUES TO INDICATE SRN STREAM S/WV TROF WILL OUTPACE ITS NRN STREAM COUNTERPART. THE RESULT IS LOW PRES DEVELOPING OFF THE SOUTHEAST COASTLINE...AND HEADING OUT TO SEA WITH A LATE CAPTURE THAT SWINGS IT TOWARDS THE CANADIAN MARITIMES. CONSENSUS IS THAT PCPN WILL ONLY BRUSH THE COAST...WITH THE MIDCOAST PERHAPS SEEING A LITTLE LONGER DURATION AS LOW PRES CUTS ACROSS BAROCLINIC ZONE. MODEL GUIDANCE HAS A VERY SHARP NRN EDGE TO THE SATURATED SNOW GROWTH ZONE...SO WE WILL BE TREADING A VERY FINE LINE OF SN OR NO SN HEADING INTO TUE. IN FACT...SFC TEMPS WILL BE MARGINAL ENOUGH THAT SOME RNFL IS POSSIBLE NEAR THE COAST. AS UPPER TROF CROSSES THE AREA THERE SHOULD BE ENOUGH FORCING AND RESIDUAL MOISTURE TO BRING SCT SHSN TO MUCH OF THE AREA BEFORE HIGH PRES BUILDS IN AND ENDS PCPN. THAT RIDGING WILL BE SHORT LIVED THOUGH...AS NEXT LOW PRES DEVELOPS AND LIFTS INTO CANADA. THIS WILL DRIVE A COLD FNT TOWARDS NEW ENGLAND. AFTER INITIAL BURST OF WAA AHEAD OF THE LOW PRES...COLD WILL SLOWLY OOZE INTO THE AREA AS FNT BECOMES ALIGNED WITH FLOW ALOFT. AS LONG AS BOUNDARY REMAINS IN THE AREA IT WILL BE HARD TO RULE OUT OVERRUNNING PCPN IN BROAD SWLY WAA REGIME. LATE IN THE WEEK STRONG HIGH PRES WILL BUILD INTO THE REGION...BEFORE WRN TROF EJECTS NEWD. GIVEN LOCATION OF HIGH PRES...IT WOULD NOT BE SURPRISING TO SEE NWP TREND COOLER WITH TIME...THOUGH THERE ARE SEVERAL DAYS BEFORE ANY DETAILS WILL BECOME MORE CLEAR. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... SHORT TERM...SHOULD SEE ALL TERMINALS GET A PERIOD OF MVFR TO IFR TODAY WITH SHSN INLAND...AND SHRA ON THE COAST. A STEADIER RA IS EXPECTED AT KRKD...AND A STEADY MIX OF RASN AT KAUG. CONDITIONS WILL IMPROVE LATE TONIGHT TO VFR FROM KPWM WWD...AND EVENTUALLY AT KAUG/KRKD ON MONDAY. LONG TERM...AREAS OF MVFR OR LOWER CONDITIONS WILL BE POSSIBLE TUE INTO WED AS OCEAN LOW PRES PASS OUT TO SEA. COASTAL TERMINALS WILL SEE LOWER CIGS AS WELL AS POSSIBLE SHSN LIMITING VSBYS. PASSAGE OF UPPER TROF MAY ALSO RESULT IN SOME MTNS SHWRS INVOF OF KHIE. && .MARINE... SHORT TERM...SOUTHERLY SURGE IN WINDS OCCURRING ATTM AND COULD SEE A FEW GUSTS UP TO 25 KT THRU SUNRISE. OTHERWISE...QUIET WEATHER WITH VSBY RESTRICTIONS EXPECTED LATER TONIGHT THROUGH SUNDAY NIGHT IN DEVELOPING RAIN AND SNOW. LONG TERM...STILL SOME UNCERTAINTY REGARDING THE TRACK OF COASTAL LOW PRES MIDWEEK. HOWEVER CONFIDENCE IS GROWING THAT SEAS WILL BUILD TO AT OR ABOVE 5 FT FOR TUE AND WED. WINDS MORE THAN LIKELY SHOULD REMAIN AT OR BELOW 25 KTS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...CEMPA SHORT TERM... LONG TERM... AVIATION... MARINE...
AREA FORECAST DISCUSSION
NWS GRAY ME
644 AM EST SUN DEC 1 2013 .SYNOPSIS... WEAK LOW PRESSURE WILL TRACK SOUTHEAST OUT OF QUEBEC AND ACROSS THE AREA TONIGHT...PRODUCING SOME LIGHT SNOW INLAND AND A MIX OF SNOW AND RAIN NEAR THE COAST. WEAK TROUGHING ALONG THE COAST KEEPS PRECIPITATION NEARBY ON MONDAY. LOW PRESSURE TRAVELS UP THE ATLANTIC COASTLINE TUESDAY...SPREADING MORE PRECIPITATION OVER THE REGION THROUGH WEDNESDAY MORNING. RIDGING BUILDS IN BRIEFLY BEFORE A COLD FRONT CROSSES THE REGION THURSDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 640 AM...FORECAST THINKING GENERALLY ON TRACK. ACTUALLY MODELS SEEM TO HAVE A DECENT HANDLE ON THE CURRENT EVENTS...WITH 06Z NAM12 HANDLING THE LARGER SCALE WELL...CAPTURING THE SHRA DEVELOPING OVER CT AND LI SOUND...AND THE RUC PICKING UP ON THE VERY LIGHT SHSN /MAYBE SNIZZLE?/...OVER THE COASTAL PLAIN....WHERE THIS SHOULD REMAIN SPOTTY THRU THE MORNING...AND CHANGE TO RA ON THE COAST....BEFORE STEADIER PRECIP DEVELOPS THIS AFTERNOON. ANY CHANGES TO THE FORECAST BASED ON CURRENT OBS HAVE BEEN MINOR AND ONLY RUN THRU APPROX THE FIRST 6 HOURS OF THE FORECAST. PREVIOUSLY...A SOMEWHAT TRICKY FORECAST TODAY INTO TONIGHT AS VERY WEAK IMPULSES ALOFT...ONE TO OUR S AND ONE TO OUR N PASS THROUGH WITHIN LESS THAN 12 HOURS OF EACH OTHER...ALTHOUGH EITHER ONE IS VERY DYNAMIC. THE FIST ONE...IN THE SRN STREAM ACTUALLY MOVES THROUGH IN THE NEXT FEW HOURS...WITH VERY WEAK SFC REFLECTION...AND LIGHT PRECIP ASSOCIATED WITH WEAK WAA AHEAD OF IT MOVED THRU OVERNIGHT. THE SECOND APPROACHES TODAY...AND GENERATES A BIT MORE LOW TO MID- LVL WAA...WHICH WORKS WITH COASTAL FRONT...AND GENERATES A AN INVERTED SFC TROUGH. THIS PRODUCES SOME MORE ORGANIZED FORCING ALONG AND JUST INLAND FROM THE COAST THIS AFTERNOON. WHILE SOME LIGHT PRECIP IS POSSIBLE THIS MORNING...THE BETTER CHC WILL BE THIS AFTERNOON INTO THE EVENING AS THE FORCING INCREASES. THIS PRECIP WILL NOT MOVE IN FROM THE WEST SO MUCH AS IT DEVELOPS ALONG THE COASTAL FRONT. COASTAL AREAS...FIRST TIER OF COASTAL ZONES...ARE LIKELY TO START AS RAIN OR SHIFT TO RAIN QUICKLY...BUT P-TYPE WILL BE SOMEWHAT OF AN ISSUE FOR INLAND AREAS OF THE COASTAL PLAIN. THE COASTAL FRONT WILL MOVE INLAND TODAY...SO SOME AREAS THAT SEE SOME LIGHT SNOW EARLY WILL CHANGE TO RAIN THIS AFTERNOON...AND MOST PLACES IN NH AND FAR WRN ME WILL BE LIMITED TO ABOUT A TENTH OF TOTAL QPF ANYWAY...WHICH WILL LIMIT TO SNOWFALL TO AN INCH OR SO...MAYBE A LITTLE MORE IN THE MTNS...WHERE RATIOS WILL BE HIGHER. MODELS SEEM TO BE FAIR AGREEMENT WHERE HIGHEST QPF WILL OCCUR...MAINLY E OF KPWM-KLEW...WHERE QPF TODAY INTO THIS EVE LOOKS BE 0.3-0.4 INCHES. SO INLAND AREAS OF THE KENNEBEC AND PENOBSCOT VLYS ARE WHERE THE MOST SNOW IS EXPECTED TO FALL. HERE WE ARE LOOKING AT GENERALLY ONE TO THREE INCHES...WITH SOME 4 INCH AMOUNTS POSSIBLE. THE BULLSYEYE FOR THE HIGHEST SNOWFALL LOOKS TO BE IN THE SKOWHEGAN-WATERVILLE-UNITY VICINITY. HOWEVER...MODELS ARE FAR FROM PERFECT WHEN IT COMES TO INVERTED TROUGHS...AND THIS COULD END UP SHIFTING A BIT. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... AS THE WEAK 500MB TROUGH ACTUALLY DEEPENS SLIGHTLY JUST TOUR E LATE TONIGHT...EXPECTING SOME WEAK RIDGING ALOFT TO DEVELOP BEHIND IT FOR MONDAY. WILL LOSE A FEW DEGREES AS WINDS SHIFT N ON THE BACK END OF THE TROUGH...ESPECIALLY IN THE N,...AND THIS COULD TURN BACK TO LIGHT SN BEFORE IT ENDS IN ERN ZONES. SO PRECIP IS EXPECTED TO WIND DOWN LATE TONIGHT...WITH A BREAK EXPECTED ON MONDAY...ALTHOUGH WE PROBABLY WILL NOT SEE MUCH SUN ON MONDAY...AS STAGNANT LOW LVL FLOW LINGERS. HIGHS SHOULD CLIMB BACK INTO THE MID 30S TO AROUND 40 AGAIN. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS WAS THE CAST THE LAST COUPLE OF NIGHTS...NWP CONTINUES TO INDICATE SRN STREAM S/WV TROF WILL OUTPACE ITS NRN STREAM COUNTERPART. THE RESULT IS LOW PRES DEVELOPING OFF THE SOUTHEAST COASTLINE...AND HEADING OUT TO SEA WITH A LATE CAPTURE THAT SWINGS IT TOWARDS THE CANADIAN MARITIMES. CONSENSUS IS THAT PCPN WILL ONLY BRUSH THE COAST...WITH THE MIDCOAST PERHAPS SEEING A LITTLE LONGER DURATION AS LOW PRES CUTS ACROSS BAROCLINIC ZONE. MODEL GUIDANCE HAS A VERY SHARP NRN EDGE TO THE SATURATED SNOW GROWTH ZONE...SO WE WILL BE TREADING A VERY FINE LINE OF SN OR NO SN HEADING INTO TUE. IN FACT...SFC TEMPS WILL BE MARGINAL ENOUGH THAT SOME RNFL IS POSSIBLE NEAR THE COAST. AS UPPER TROF CROSSES THE AREA THERE SHOULD BE ENOUGH FORCING AND RESIDUAL MOISTURE TO BRING SCT SHSN TO MUCH OF THE AREA BEFORE HIGH PRES BUILDS IN AND ENDS PCPN. THAT RIDGING WILL BE SHORT LIVED THOUGH...AS NEXT LOW PRES DEVELOPS AND LIFTS INTO CANADA. THIS WILL DRIVE A COLD FNT TOWARDS NEW ENGLAND. AFTER INITIAL BURST OF WAA AHEAD OF THE LOW PRES...COLD WILL SLOWLY OOZE INTO THE AREA AS FNT BECOMES ALIGNED WITH FLOW ALOFT. AS LONG AS BOUNDARY REMAINS IN THE AREA IT WILL BE HARD TO RULE OUT OVERRUNNING PCPN IN BROAD SWLY WAA REGIME. LATE IN THE WEEK STRONG HIGH PRES WILL BUILD INTO THE REGION...BEFORE WRN TROF EJECTS NEWD. GIVEN LOCATION OF HIGH PRES...IT WOULD NOT BE SURPRISING TO SEE NWP TREND COOLER WITH TIME...THOUGH THERE ARE SEVERAL DAYS BEFORE ANY DETAILS WILL BECOME MORE CLEAR. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... SHORT TERM...SHOULD SEE ALL TERMINALS GET A PREIOD OF MVFR TO IFR TODAY WITH SHSN INLAND...AND SHRA ON THE COAST. A STEADIER RA IS EXPECTED AT KRKD...AND A STEADY MIX OF RASN AT KAUG. CONDITIONS WILL IMPROVE LATE TONIGHT TO VFR FROM KPWM WWD...AND EVENTUALLY AT KAUG/KRKD ON MONDAY. LONG TERM...AREAS OF MVFR OR LOWER CONDITIONS WILL BE POSSIBLE TUE INTO WED AS OCEAN LOW PRES PASS OUT TO SEA. COASTAL TERMINALS WILL SEE LOWER CIGS AS WELL AS POSSIBLE SHSN LIMITING VSBYS. PASSAGE OF UPPER TROF MAY ALSO RESULT IN SOME MTNS SHWRS INVOF OF KHIE. && .MARINE... SHORT TERM...SOUTHERLY SURGE IN WINDS OCCURRING ATTM AND COULD SEE A FEW GUSTS UP TO 25 KT THRU SUNRISE. OTHERWISE...QUIET WEATHER WITH VSBY RESTRICTIONS EXPECTED LATER TONIGHT THROUGH SUNDAY NIGHT IN DEVELOPING RAIN AND SNOW. LONG TERM...STILL SOME UNCERTAINTY REGARDING THE TRACK OF COASTAL LOW PRES MIDWEEK. HOWEVER CONFIDENCE IS GROWING THAT SEAS WILL BUILD TO AT OR ABOVE 5 FT FOR TUE AND WED. WINDS MORE THAN LIKELY SHOULD REMAIN AT OR BELOW 25 KTS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...CEMPA SHORT TERM... LONG TERM... AVIATION... MARINE...
AREA FORECAST DISCUSSION
NWS CARIBOU ME
630 AM EST SUN DEC 1 2013 .SYNOPSIS... LOW PRESSURE IS EXPECTED TO CROSS THE STATE TODAY AND REDEVELOP IN THE GULF OF MAINE TONIGHT, PASSING WELL E OF THE REGION ON MONDAY. ANOTHER LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE MIDDLE PART OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... UPDATE: ADJUSTED THE PRECIP CHANCES LINING THEM UP W/THE RADAR TRENDS AND OBS. KEPT THE HIGH PRECIP CHANCES(60-80%) TOWARD THE EASTERN SIDE OF THE CWA AND SCALED THEM BACK FURTHER W THROUGH THIS MORNING. REPORTS COMING SHOW AN INCH OR LESS OF ACCUMULATION W/WHAT FELL OVERNIGHT WEAK LOW PRES MOVING ACROSS THE EASTERN GREAT LAKES IS FCST TO MOVE ACROSS SOUTHERN NEW ENGLAND THIS AFTERNOON AND THEN INTO THE GULF OF MAINE. THE CONCERN IS WHERE TO DRAW THE RAIN/SNOW LINE AS WAA MAKES ITS WAY TO THE BLYR. TEMPERATURES ARE FCST TO REACH INTO THE UPPER 20S TO AROUND 30 ACROSS THE NORTHERN 1/2 OF THE CWA WHILE LOW TO MID 30S ARE EXPECTED FOR CENTRAL AND DOWNEAST AREAS. AN INVERTED TROF EXTENDING FROM THE LOW COMBINED W/SOME FRONTOGENETICAL FORCING AT 1000-700MB WILL LEAD TO A REFORMATION OF PRECIP AND AN ENHANCEMENT OF THE PRECIP. USING THE BUFKIT PROFILES AND SOUNDINGS, THINKING HERE IS THAT SNOW WILL REDEVELOP ACROSS PORTION OF NORTHEAST MAINE W/THE HEAVIEST AXIS ACROSS THE HOULTON AND DANFORTH REGION W/LESS SNOW NORTH AND WEST. S OF OF THE HOULTON-DANFORTH LINE, TEMPERATURES WILL WARM INTO THE MID 30S TO ALLOW FOR SNOW TO MIX WITH AND CHANGEOVER TO RAIN. THIS IN TURN WILL CUT DOWN ON SNOWFALL LATER THIS AFTERNOON INTO TONIGHT. DECISION WAS TO GO AHEAD AND ADD NORTHERN PENOBSCOT AND SE AROOSTOOK COUNTY IN THE WINTER WEATHER ADVISORY THROUGH MONDAY MORNING DUE TO ENHANCED FRONTOGENTICAL FORCING LEADING TO HEAVY SNOW BURSTS. LATEST SNOW TOTAL MAP SHOWS A GENERAL 4-8 INCHES IN THE ADVISORY AREA W/1-4 INCHES N AND W. THE COAST AND EXTREME EASTERN WASHINGTON COUNTY FROM MEDDYBEMPS TO EASTPORT WILL SEE 0.30 TO 0.70 INCHES OF RAINFALL AFTER SOME INITIAL SNOWFALL. SNOW WILL CONTINUE INTO TONIGHT ACROSS THE NORTHEASTERN SECTION OF MAINE INCLUDING CARIBOU-PRESQUE ISLE DOWN THROUGH DANFORTH. WEST OF THIS AREA, LITTLE OR NO SNOW AND RAIN/SNOW S OF THIS AREA W/RAIN FOR THE COAST AS THE WARM AIR IS FCST TO STAY IN. TEMPERATURES WILL DROP BACK INTO THE UPPER TEENS AND LOWER 20S NORTH AND WEST AND MID TO UPPER 20S FOR CENTRAL AREAS. LOW 30S FOR THE DOWNEAST REGION INCLUDING THE COAST. && .SHORT TERM /MONDAY THROUGH TUESDAY/... SNOW WILL CONTINUE TO WIND DOWN EARLY MONDAY AS THE INVERTED TROF EXTENDING FROM THE CANADIAN MARITIMES THROUGH DOWNEAST MAINE MOVES OFF TO THE NORTHEAST. THERE MAY STILL BE SOME LINGERING LIGHT SNOW OR SNOW SHOWERS PARTICULARLY ACROSS EASTERN AREAS OTHERWISE EXPECT MOSTLY CLOUDY SKIES ACROSS THE REGION. MONDAY NIGHT WILL BE MOSTLY CLOUDY BUT DRY AS WEAK HIGH PRESSURE RIDGES DOWN FROM THE NORTH. ATTENTION THEN TURNS TO ANOTHER LOW PRESSURE SYSTEM THAT WILL BE MOVING NORTHEAST ACROSS THE WESTERN ATLANTIC. THIS SYSTEM MAY BRINGS SOME PRECIPITATION TO THE REGION LATER TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... MODELS SEEM TO BE COMING INTO BETTER AGREEMENT FOR THE NEXT SYSTEM TUESDAY NIGHT AND WEDNESDAY. STILL SOME MODEL DIFFERENCES BUT THE CONSENSUS SOLUTION IS FOR THE LOW TO TRACK FAR ENOUGH EAST THAT ANY IMPACTS IN OUR REGION WOULD BE ACROSS DOWNEAST/EASTERN MAINE. A WEAK BOUNDARY WILL CROSS THE REGION BY LATE WEEK WITH SOME SNOW/RAIN SHOWERS POSSIBLE. AGAIN...WILL STICK CLOSE TO THE SUPERBLEND. HIGH PRESSURE WILL BUILD EAST TOWARD THE REGION BY SATURDAY. && .AVIATION /11Z SUNDAY THROUGH THURSDAY/... NEAR TERM: MVFR W/PERIODS OF VFR THIS MORNING DROPPING TO MVFR AND EVEN IFR LATER THIS MORNING ON INTO TONIGHT. SNOW ACROSS THE NORTHERN TERMINALS W/SNOW TO RAIN FOR KBGR TO KBHB. SHORT TERM: MVFR CONDS ARE POSSIBLE EARLY MONDAY THEN VFR CONDS EXPECTED MONDAY NIGHT INTO TUESDAY. MVFR CONDS ARE POSSIBLE IN SOME LIGHT PRECIP LATE TUESDAY AND INTO EARLY WEDNESDAY. VFR ON THURSDAY. && .MARINE... NEAR TERM: DECIDED TO GO W/A SCA THROUGH LATE MORNING. WINDS GUSTING TO 25 KTS AS LLVL JET OF 30 KT MOVES ACROSS THE WATERS. THE GFS AND NAM AS WELL AS THE LATEST RAP MODEL PICK UP ON THIS FEATURE. WINDS ARE FCST TO DROP OFF THIS AFTERNOON AS THE LLVL JET SHIFTS TO THE E. SEAS ARE AT 5FT AND COULD TIP 6 FT ESPECIALLY AT 44027(JONESPORT) THIS MORNING. SEAS WILL GRADUALLY SUBSIDE TONIGHT BELOW 4 FT. SHORT TERM: WINDS/SEAS WILL BE BELOW SCA LEVELS MON AND MON NIGHT. WIND/SEAS MAY INCREASE TO SCA LEVELS TUE/TUE NIGHT. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ005-006- 011-016-017-032. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST THIS MORNING FOR ANZ050>052. && $$ NEAR TERM...HEWITT SHORT TERM...DUDA LONG TERM...DUDA AVIATION...HEWITT/DUDA MARINE...HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
641 AM EST SUN DEC 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM EST SUN DEC 1 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER THE UPR GRT LKS TO THE SW OF UPR TROF CENTERED OVER NRN QUEBEC. IN THE WAKE OF DEPARTING SHRTWV MOVING THRU SW QUEBEC...A SHRTWV RDG IS SLIDING SEWD THRU NW ONTARIO...SUPPORTING A SFC HI PRES OVER FAR NW ONTARIO. CLOSER TO UPR MI...A LO PRES TROF IS APRNT NEAR THE LK SUP SHORE OF UPR MI AND EXTENDING WNW IN THE MN ARROWHEAD. THIS TROF HAS BEEN THE FOCUS FOR SOME BANDS OF HIER REFLECTIVITY SHOWN ON THE MQT 88D REFLECTIVITY WITH UPSLOPE N WINDS NEAR LK SUP. SINCE H85 TEMPS ARE ONLY -7 TO -8C AND THE ACCOMPANYING MSTR IS RELATIVELY SHALLOW AS DIAGNOSED FM THE MQT 88D VWP AS WELL AS THE 00Z INL RAOB...WHICH SHOWS INVRN BASE NEAR H85 UNDER VERY DRY MID LVLS AHEAD OF APRCHG SHRTWV RDG...ASSOCIATED PCPN HAS BEEN A MIX OF -SHSN AND SOME -FZDZ. THE 00Z YPL RAOB SHOWS SHALLOW MSTR AS WELL BLO AN INVRN NEAR H925...SO PLENTY OF LO CLDS EXTEND WELL N INTO ONTARIO. THE AIR IS MUCH COLDER THERE WITH SFC TEMPS IN THE TEENS...SO SPOTTY LGT PCPN IS IN THE FORM OF SN. MAIN FCST CONCERN IN THE SHORT TERM IS THE POTENTIAL FOR SOME LGT -SN AND -FZDZ. TODAY...WITH APRCH OF SHRTWV RDG NOW IN NW ONTARIO...LARGER SCALE QVECTOR DVGC/MID LVL DRYING IS FCST TO SLOWLY WEAKEN...BUT NOT ELIMINATE ALTOGETHER...THE SFC TROF NOW OVER LK SUP AND INHIBIT ANY LARGER SCALE PCPN. SFC HI PRES NOW OVER FAR NW ONTARIO IS PROGGED TO DRIFT ONLY SLOWLY SE ACRS NRN ONTARIO...WITH THE CWA DOMINATED BY WEAKENING AND SLOWLY VEERING LLVL NE FLOW. WL CONT TO CARRY SOME CHC POPS NEAR LK SUP IN AREA THAT WL EXPERIENCE AN UPSLOPE WIND COMPONENT NEAR LINGERING LO PRES TROF OVER THE NCENTRAL. WHETHER THIS PCPN IS ALL -SN OR REMAINS MIXED WITH SOME -FZDZ IS THE PRIMARY CONCERN. MODELS REMAIN INCONSISTNET ON FCST H85 TEMPS AND MSTR DEPTH. FCST H85 TEMPS ARE FCST TO FALL TO ARND -9C BY THE 00Z NAM/LOCAL WRF-ARW TO -11C BY THE GFS. GIVEN THE WEAKENING WINDS THAT WL LIMIT LLVL CAD AND EXPECTED NEGATIVE DYNAMICS AS WELL AS UPSTREAM RAOBS...PREFER THE SOMEWHAT WARMER H85 TEMPS AND SHALLOWER MSTR PROFILE/LOWER INVRN BASE SHOWN BY THE 00Z LOCAL WRF-ARW MODEL. THIS MODEL SHOWS THE UPSLOPE UVV AND INVRN BASE REMAINING NR 5K FT AGL AND BLO THE DGZ... SO WL RETAIN A MIX OF -SN/-FZDZ THRU THE DAY. MARGINAL H85 TEMPS RELATIVE TO LK WATER TEMP ARND 4C WL LIMIT ANY SN ACCUM. WITH PLENTY OF LO CLDS...TEMPS SHOULD REBOUND ONLY SLIGHTLY THRU THE DAY. TNGT...VERY LGT LLVL WINDS ARE PROGGED TO SLOWLY VEER TO THE E AND SE AS THE CENTER OF SFC HI PRES SHIFTS INTO QUEBEC. SUSPECT LINGERING LK EFFECT PCPN WL DRIFT INTO THE KEWEENAW AS THE FLOW GRDLY SHIFTS TO THE ESE. IN THE ABSENCE OF ANY DYNAMIC SUPPORT... EXPECT THE INVRN BASE TO REMAIN NEAR 5K FT. AS POINTED OUT BY THE DAYSHIFT...LK VORTICES OFTEN DVLP WITH THE FCST LGT LLVL WINDS. BUT MARGINAL H85 TEMPS ARND -9C WL LIMIT THE INTENSITY OF ANY SHSN THAT WOULD ACCOMPANY THESE FEATURES...AND THE LGT WINDS WL INHIBIT BANDING. SO ANY SN ACCUMS SHOULD REMAIN LGT. SINCE THE H85 TEMPS WL REMAIN MARGINAL FOR LES AND UPSLOPE OMEGA WL REMAIN BLO THE DGZ...INCLUDED A MENTION OF FZDZ. LINGERING LO CLDS WL LIMIT THE DIURNAL TEMP FALL. BEST CHC FOR SOMEWHAT LOWER TEMPS WL BE OVER THE E WITH A RELATIVELY UNMODIFIED/DOWNSLOPE E FLOW OFF ONTARIO THAT MIGHT ALLOW FOR SOME BREAKS IN THE SC. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 430 AM EST SUN DEC 1 2013 MONDAY THROUGH TUESDAY MORNING...UPPER LEVEL 500MB TROUGHING IS EXPECTED TO REMAIN IN PLACE ACROSS THE CWA THROUGH THIS TIME PERIOD AS A WEAK INVERTED RIDGE WEDGES IN ACROSS THE AREA AT THE SURFACE. A SLIGHTLY DRYER AIRMASS WILL ALSO LINGER THROUGH TUESDAY MORNING WHICH CAN BE SEEN BY ANALYZING 1000-500MB RH. THE NEXT SURFACE LOW CAN BE SEEN PUSHING ACROSS THE NORTHERN ROCKIES MONDAY NIGHT AND EJECTING INTO THE NORTHERN OR CENTRAL PLAINS TUESDAY MORNING AS A MUCH DEEPER UPPER LEVEL 500MB TROUGH BUILDS IN OVER THE WESTERN U.S. THERE ARE STILL SOME MODEL DIFFERENCE HOWEVER WITH THE 00Z GFS/NAM BEING A BIT FASTER AND STRONGER WITH THIS LOW. THE 00Z GFS/NAM PLACE THE SURFACE LOW ALONG THE NORTH AND SOUTH DAKOTA BORDER BY 12Z ON TUESDAY. THE 00Z EC/GEM ARE THE SLOWER OF THE SOLUTIONS KEEPING THE LOW A BIT FARTHER SOUTH AND REMAINING OVER THE CENTRAL PLAINS JUST A BIT EAST OF THE ROCKIES. EITHER WAY...BOTH SOLUTIONS KEEP THE PRECIPITATION TO THE WEST OF THE AREA THROUGH THIS TIME PERIOD. LIGHT EASTERLY WINDS THROUGH MONDAY NIGHT WILL SLOWLY BECOME SOUTHEASTERLY BY TUESDAY. THIS ALONG WITH H850 TEMPS AROUND -8 TO -10 C WILL HELP TO KEEP CONDITIONS CLOUDY WITH VERY LIGHT PRECIPITATION POSSIBLE...MAINLY OVER THE KEWEENAW PENINSULA. TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...THIS TIME PERIOD REMAINS UNCERTAIN WHICH HAS BEEN THE CASE OVER THE PAST SEVERAL DAYS...WITH POOR MODEL AGREEMENT EVEN AS THIS TIME PERIOD IS RAPIDLY APPROACHING...HOWEVER...THE 00Z EC TENDS TO BE TRENDING A BIT CLOSER TO THE NAM AND GFS SOLUTIONS. THE GFS/NAM SOLUTIONS BRING INCREASED MOISTURE AND PRECIPITATION INTO THE CWA BY 18Z TUESDAY...WHILE THE EC/CANADIAN KEEP THE SYSTEM CENTERED OVER NORTHEASTERN KS DURING THAT TIME FRAME. THE 00Z GFS PLACES THE SURFACE LOW AND VERTICALLY STACKED CLOSED UPPER LEVEL 500MB LOW OVER WESTERN WI AT 00Z WED WHILE THE 00Z EC HAS THE MORE ELONGATED SURFACE LOW OVER CENTRAL IOWA INTO CENTRAL PLAINS. BY 18Z WED THE 00Z RUN OF THE GFS PUSHES THE LOW TO THE NORTHEAST OF LAKE SUPERIOR WHILE THE EC IS JUST PLACING THE SURFACE LOW AND UPPER LEVEL ENERGY INTO THE WESTERN PORTION OF WI. DEFINITELY EASY TO SEE THAT THERE ARE STILL SIGNIFICANT DIFFERENCES BETWEEN THESE MODELS...HOWEVER...A BETTER SIGNAL EXISTS SINCE THE EC IS TRENDING A BIT CLOSES TO THE FASTER SOLUTIONS...THE BEST IDEA FOR THE TIME BEING WILL BE MORE OF A MIDDLE OF THE ROAD APPROACH...WITH A SLIGHT LEAN TOWARD THE FASTER SOLUTIONS. THIS WOULD FAVOR A LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT TIME FRAME FOR THE MORE CONCENTRATED AREA OF PRECIPITATION. SOUNDINGS FOR THIS TIME PERIOD INDICATE WARMER AIR LIFTING NORTHWARD ON THE EAST SIDE OF THE LOW HELPING TO TRANSITION THE PRECIPITATION OVER TO A RAIN SNOW MIXTURE FOR AT LEAST THE EASTERN HALF OF THE UPPER PENINSULA AS A FAIRLY DEEP WARM LAYER BUILDS IN THROUGH MUCH OF THE BOUNDARY LAYER. THE FAR WESTERN PORTION OF THE U.P. MAY END UP SEEING MAINLY SNOW AS SHOWN BY ANALYZING BOTH THE EC AND GFS PROFILES. IN ANY CASE THIS SYSTEM WILL BE CLOSELY WATCHED OVER THE NEXT SEVERAL MODEL RUNS TO SEE IF BETTER UPPER AIR SAMPLING CAN ENTERTAIN GREATER MODEL AGREEMENT. THURSDAY THROUGH SATURDAY...ATTENTION TURNS TO A POTENTIALLY PROLONGED PERIOD OF LAKE EFFECT SNOW. MODELS ACTUALLY BECOME IN BETTER AGREEMENT WITH THE SYSTEM DURING THIS TIME FRAME. EACH OF THE MODELS SHIFT THE SURFACE LOW NORTHEASTWARD TO NEAR JAMES BY BY 12Z THURSDAY. AS THIS HAPPENS WINDS WILL SHIFT TO THE WEST ALLOWING LAKE EFFECT SNOW TO DEVELOP IN AREAS FAVORED BY THAT PARTICULAR WIND DIRECTION. THURSDAY THROUGH THURSDAY NIGHT THE LAKE EFFECT SNOW WILL PROBABLY JUST BE STARTING ACROSS THE AREA...BUT SHOULD REMAIN LIGHT. TRIED TO TREND THE LES CHANCES UPWARD FRIDAY THROUGH SATURDAY AS AN UPPER LEVEL TROUGH/SHORTWAVE AND INCREASED MOISTURE SHIFTS INTO THE AREA...ALLOWING FOR ENHANCED LIFT FOR LES TO DEVELOP. ITS STILL A BIT TOO EARLY TO TELL FOR SURE ABOUT THE OVERALL SNOWFALL TOTALS...BUT IT DOES LOOK LIKE FRIDAY INTO SATURDAY WILL BE SNOW FOR WESTERLY WIND FAVORED AREAS OF THE UPPER PENINSULA. AS EARLIER SHIFT STATED THE SNOW TO LIQUID RATIOS WILL LIKELY BE SLIGHTLY LOWER THAN USUAL FOR LES AS THE DGZ IS FAIRLY SHALLOW AND FAIRLY LOW IN THE ATMOSPHERE...WHICH TENDS TO INHIBIT THE MORE FAVORABLE GROWTH RATES FOR SNOW. STAY TUNED THOUGH AS THIS LES EVENT GETS CLOSER TOWARD THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 641 AM EST SUN DEC 1 2013 EXPECT MVFR CIGS TO PREDOMINATE AT ALL 3 TAF SITES THIS FCST PERIOD WITH RELATIVELY SHALLOW MOIST LYR TRAPPED BLO SUBSIDENCE INVRN ASSOCIATED WITH HI PRES OVER ONTARIO. THERE MAY ALSO BE SOME -SN AND PERHAPS SOME -FZDZ MAINLY THIS MRNG AT IWD AND SAW IN THE PRESENCE OF AN UPSLOPE N-NE WIND OFF LK SUP ON THE SRN FLANK OF THE HI TO THE N. BUT AS THE WIND DIMINISHES AND SLOWLY VEERS TO A MORE ESE DIRECTION BY THIS EVNG...THE PCPN SHOULD DIMINISH AT THESE LOCATIONS AND PERHAPS SHIFT INTO CMX. DOWNSLOPE NATURE OF THIS FLOW INTO IWD AND PERSISTENT SUBSIDENCE MAY CAUSE THE LO CLDS TO BREAK UP AT THIS SITE LATER TNGT...BUT LGT WIND SPEEDS MAY CAUSE THIS DOWNSLOPE COMPONENT TO BE NEGLIGIBLE. SO MAINTAINED MVFR FCST FOR NOW. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 430 AM EST SUN DEC 1 2013 EXPECT NE WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH UNDER 15 KTS AND SLOWLY VEER INTO MON AS A WEAK PRES GRADIENT EXTENDING S FROM HI PRES MOVING THRU ONTARIO DOMINATES THE UPPER LAKES. STRONGER E TO SE WINDS UP TO 25 TO PERHAPS 30 KTS WILL THEN DEVELOP INTO MID WEEK AS THE GRADIENT SHARPENS OVER LAKE SUP BETWEEN THE HI PRES SHIFTING INTO QUEBEC AND LO PRES MOVING NE FROM THE PLAINS. THERE WILL BE A SHARP WIND SHIFT TO THE WNW BY THU FOLLOWING THE PASSAGE OF THE LO TO THE NE. DEPENDING ON THE TRACK AND INTENSITY OF THIS LO...THERE COULD BE A W GALE ON THU INTO FRI. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KEC AVIATION...KC MARINE...KC
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
555 AM CST Sun Dec 1 2013 .SHORT TERM: (Through Late This Afternoon) Issued at 335 AM CST Sun Dec 1 2013 Think the challenge for today will be forecasting cloud cover. A stratus deck between 4000-5000ft is moving across he eastern Ozarks and parts of Southern Illinois this morning. Think this area of stratus will continue advecting eastward faster than the western edge will erode as has been the case for the past few hours. Therefore there should be substantial cloud cover over southeast Missouri and parts of southern Illinois this morning. The 00Z NAM eventually cleared it out and this matches well with satellite trends at this time; however the RAP backbuilds the cloud cover, as does the 06Z NAM and this suggests that areas generally southeast of a line from Vichy, MO to Salem, IL may not see much sun today. Am sticking closer to the less cloudy solution at this time, but this may ultimately prove to be too optimistic. Temperatures may be challenging as well. Can`t seem to forecast warm enough the past couple of days. Missed highs both Friday and Saturday by to to three degrees. Lingering cloud cover over the eastern Ozarks and southwest Illinois may make this especially challenging. For highs today, used a blend of 925 mix-down temperatures and MOS. Tweaked southern zones down a couple of degrees from that to account for cloud cover, and the rest of the area up a degree or two to try to compensate for my apparent cool bias. Britt .LONG TERM: (Tonight through Saturday) Issued at 335 AM CST Sun Dec 1 2013 (Tonight - Tuesday) Have not made too many changes to going forecast during this period. Low level moisture progs suggest that stratus will redevelop this evening, particularly over the southern and eastern part of the CWA. Have kept chance of light drizzle in these areas where this moisture will be the deepest and there will be some very light ascent. As we go into Monday, GFS/NAM/ECMWF all show a weak shortwave trough racing into the area from the west, though it is not as deep as was forecast 24 hours ago. Have left chance of sprinkles in for tomorrow morning as the trough axis will move through the area by midday. Temperatures will begin to warm up ahead ahead of the next storm system. Expect temperatures to climb into the 50s on Monday with some spots reaching 60 on Tuesday. (Wednesday - Saturday) Main concern continues to be the potential for a wintry precipitation and the big cool down mid to late week. There still ia a great deal of uncertainty regarding timing, precipitation types and amounts. While the GFS is still the fastest with the passage of the cold front, the 00Z ECMWF now brings the cold front through the area during the day on Wednesday instead of Wednesday Night. The cold front will have moved to the south of the area Wednesday. Best forcing for precipitation will hinge on mid-level frontogenesis and shortwave troughs moving through fast west- southwesterly flow aloft. Have likely pops on Thursday and Thursday Night over southeastern half of the CWA with the chance continuing into Friday. Will continue to have a simple mix of rain and snow because of the uncertainty for now, but thermal profiles from forecast soundings certainly suggest the potential for sleet or freezing rain over the southern half of the CWA. 850mb temperatures by next Friday and Saturday will be in the -10 to -12C range supporting highs only in the 20s with lows in the single digits and teens. Britt && .AVIATION: (For the 12z TAFs through 12z Monday Morning) Issued at 541 AM CST Sun Dec 1 2013 Primary concern this morning is an area of fog over central Missouri where VSBYS AOB 1SM are being reported. Expect this fog to lift and dissipate after 14Z this morning. Some patchy fog with VSBYS between 2-5SM have been reported further east this morning as well, however the lower VSBYS have been intermittent. At any rate, expect VFR flight conditions to prevail after 15-16Z this morning. Am concerned that fog will again be an issue tonight after 06Z. Not sure yet how low to go, so started out with MVFR conditions, but will not be surprised to see lower VSBYS by 12Z Monday morning. Winds will be variable through 12Z Monday as a weak cold front becomes nearly stationary over the area, and then begins to drift back to the north late in the period. Specifics for KSTL: Expect VFR flight conditions to prevail at Lambert at least through 06Z tonight. Guidance is hinting that there could be some MVFR VSBYS in fog after 06Z tonight, and I have lowered VSBYS in the other STL Metro TAFs; however it`s tough to get fog at Lambert due to the metro heat island so have left mention of fog out for now. Winds will be pretty wishy-washy over the next 24 hours as a weak cold front becomes nearly stationary over the area, but the wind will pick up from the south after 12Z Monday as the front moves back to the north. Carney && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
947 AM EST SUN DEC 1 2013 .SYNOPSIS... LOW PRESSURE WILL GRADUALLY DEVELOP OFF THE CAROLINA COAST LATE TODAY INTO TONIGHT...MOVING OUT TO SEA MONDAY. WEAK HIGH PRESSURE WILL MOVE ACROSS THE AREA TUESDAY AND OFFSHORE WEDNESDAY...BRINGING SEVERAL DAYS OF WARM TEMPERATURES LATE THIS WEEK. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM SUNDAY...MODELS OVER THE PAST TWO DAYS HAVE DONE AN ABYSMAL JOB FORECASTING HOW THE WEATHER HAS ACTUALLY UNFOLDED OVER THE PAST 6-12 HOURS. NOT ONLY IS ISENTROPIC LIFT STRONGER AND COVERAGE OF SHOWERS MORE WIDESPREAD NOW OVER THE COASTAL WATERS THAN WAS EXPECTED...BUT THE 06Z GFS AND NAM PLUS THE 12Z RUC PAINT A PICTURE OF DRIER WEATHER DEVELOPING INTO TONIGHT AS WHAT ISENTROPIC LIFT WE CURRENTLY HAVE TRICKLES OFFSHORE AND DRIER AIR ARRIVES FROM THE WEST AND SOUTHWEST WITHIN THE 5000-10000 FOOT LAYER. COMPARED TO 12Z SOUNDINGS ALL THE MODELS ARE STRUGGLING WITH WHAT IS GOING ON BELOW 10000 FEET THIS MORNING. THIS WAS PARTICULARLY APPARENT AT CHS WHERE THE GFS HAD A HORRIBLE HANDLE (TOO WET) ON MOISTURE WITHIN THE 800-900 MB LAYER. ALL THE MODELS FAILED TO PROPERLY SHOW WARM TEMPERATURES BETWEEN 850-1000 MB OBSERVED ON THE MHX SOUNDING. NEEDLESS TO SAY...THIS CASTS DOUBT ON WHAT (IF ANY) MODEL GUIDANCE IS TRUSTWORTHY GOING FORWARD THROUGH THIS AFTERNOON INTO TONIGHT. MY CURRENT IDEA (BASED ON CURRENT RADAR AND SATELLITE IMAGERY SPRINKLED WITH RUC/HRRR GUIDANCE THROUGH THE AFTERNOON) IS FOR A MUCH DRIER AFTERNOON THAN WAS EXPECTED. I HAVE REMOVED POPS FOR THE PEE DEE COUNTIES IN SOUTH CAROLINA AND TRIMMED BACK POPS ALONG THE COAST TO NO HIGHER THAN 30-40 PERCENT...HIGHEST ACROSS SOUTHPORT/ CAROLINA BEACH. WITH NO PRECIPITATION INLAND AND SATELLITE IMAGERY SHOWING BREAKS IN THE OVERCAST ACROSS MUCH OF CENTRAL AND EASTERN SOUTH CAROLINA I HAVE RAISED FORECAST HIGHS BY 3-4 DEGREES FROM FLORENCE TO LUMBERTON...WITH UPPER 50S EXPECTED FOR MOST AREAS THIS AFTERNOON. DRIER AIR ARRIVING THIS AFTERNOON WITHIN THE LAYER CURRENTLY GENERATING ISENTROPIC LIFT AND SHOWERS (6000-10000 FT) SHOULD LEAD TO DRY CONDITIONS EVEN ALONG THE COAST. SURPRISINGLY... THIS DRIER TREND MAY EVEN CONTINUE INTO TONIGHT AS THE 06Z MODELS (FOR WHAT THEY`RE WORTH) SHOWING SHOWERS REMAINING MAINLY OFFSHORE. LET`S HOPE THE 12Z RUNS CAN LEND A HAND WITH THAT PORTION OF THE FORECAST. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...A SLEW OF SHORTWAVES WILL CROSS THE CAROLINAS, GA, AND NRN FL ON MONDAY...SOMEWHAT CONGEALING OFF THE SOUTHEAST COAST LATE IN THE DAY. THE RESULTING SURFACE WAVE OF LOW PRESSURE THAT HAD BEEN PROGGED TO DEVELOP NOW LOOKS CONSIDERABLY WEAKER. MORNING RAIN CHANCES ASSOCIATED WITH THIS FEATURE WILL BE FOCUSED ALONG THE CAPE FEAR/COASTAL NC ZONES BEFORE DECREASING PERHAPS RAPIDLY LATER IN THE DAY AS DIFFERENTIAL VORTICITY ADVECTION TURNS QUITE NEGATIVE AND THE LOW LEVEL UPGLIDE LOOKS TO SHUT OFF AS WELL. TUESDAY THEN BRINGS ZONAL MID LEVEL FLOW THAT SHOULD KEEP THINGS DRY. AT THE SURFACE THERE WILL WON`T BE MUCH GRADIENT AS A WEAK HIGH OVER THE CAROLINAS FILLS THE SPACE IN BETWEEN THE DEEPENING ATLANTIC LOW AND A LARGE SYSTEM GATHERING STRENGTH OVER THE NRN PLAINS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...RIDGE AXIS TO DRIFT OFFSHORE ON WEDNESDAY PAVING THE WAY FOR SOME RETURN FLOW. EXPECT ABOVE NORMAL HIGHS FOR THE FIRST TIME IN QUITE A WHILE DESPITE POSSIBLE INCREASE IN LOW TO MID LEVEL CLOUDINESS. THURSDAY TOO WILL BE MILD AND RATHER CLOUDY AS THE RETURN FLOW VEERS SOMEWHAT DUE TO THE APPROACH OF A COLD FRONT FROM THE WEST. THE NE TO SW ORIENTATION OF THE BOUNDARY WILL HAVE IT QUITE LINED UP WITH THE MID LEVEL FLOW MAKING FOR VERY SLOW PROGRESSION. IN FACT WE SEE SOME DIFFERENCES IN THE SPEED AT WHICH THE BOUNDARY APPROACHES AND MOVES THROUGH BETWEEN VARIOUS MODELS. GIVEN THE VERTICAL DIRECTIONAL ALIGNMENT OF THE FLOW THE SLOWER SOLUTIONS SEEM MORE PLAUSIBLE. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 12Z...QUITE A BIT OF STRATA CUMULUS OVER THE CWA...LOWEST AT THE MYRTLES. THE STRATA CU WILL BE IN AND OUT...REPLACED WITH A MID CLOUD CEILING THIS AFTERNOON. THE GRADIENT WILL BE VERY WEAK TODAY WITH HIGH PRESSURE CENTERED OVERHEAD...PERHAPS LIGHT AND VARIABLE WOULD BEST DESCRIBE THE WINDS TODAY. LOW PRESSURE DEVELOPS OFFSHORE TONIGHT...WITH A FEW SPRINKLES POSSIBLE. AN MVFR CEILING IS POSSIBLE THIS EVENING. EXTENDED OUTLOOK...CHANCE OF RAIN ON MONDAY WITH INTERMITTENT MVFR/IFR CONDITIONS EXPECTED. MAINLY VFR TUESDAY THROUGH THURSDAY. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 930 AM SUNDAY...FAIRLY WIDESPREAD SHOWER ACTIVITY COVERS THE OUTER PORTION OF THE COASTAL WATERS THIS MORNING...EXCEPT NEAR CAPE FEAR WHERE THE SHOWERS ARE ALSO OCCURRING IN THE NEARSHORE WATERS. THIS IS OCCURRING IN ASSOCIATION WITH A WEAK COASTAL TROUGH NEAR THE WESTERN EDGE OF THE GULF STREAM. NORTH WINDS SHOULD VEER A LITTLE MORE NORTHEASTERLY BY THIS AFTERNOON...WITH NO INCREASE IN WIND SPEEDS EXPECTED. SEAS ARE THE BIG STORY AWAY FROM SHORE AS A PERSISTENT 9-SECOND EASTERLY SWELL CONTINUES TO BRING SIGNIFICANT WAVE ENERGY INTO THE AREA. THE GENESIS REGION FOR THIS SWELL IS ACTUALLY WELL OUT INTO THE CENTRAL ATLANTIC WHERE A COUPLE THOUSAND MILES OF EASTERLY FLOW ALONG THE SOUTH SIDE OF NORTH ATLANTIC HIGH PRESSURE IS BUILDING QUITE A WAVE FETCH. SEAS OUT AT FRYING PAN SHOALS ARE AROUND 5 FEET DUE TO THIS SWELL...WITH 3 FEET REPORTED AT THE BUOY SEVERAL MILES SOUTH OF THE MOUTH OF THE CAPE FEAR RIVER. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...A SERIES OF CONGEALING UPPER LEVEL DISTURBANCES WILL FORM A SURFACE LOW OFF THE COAST BY MONDAY MORNING. THIS FEATURE IS NOW SUPPOSED TO BE WEAKER THAN EARLIER FORECASTS AND POSSIBLY FURTHER OUT TO SEA AS WELL. THIS INCREASES FORECAST CONFIDENCE THAT NO ADVISORIES OR HEADLINES WILL BE NEEDED AT THIS TIME AS WINDS MAY BE CAPPED IN THE 10 TO 15 KT RANGE OVER NORTHERN ZONES WITH PERHAPS JUST 10 KT SOUTH. EVEN LIGHTER WINDS AND SEAS MAY BE IN THE OFFERING ON TUESDAY AS THIS SYSTEM EXITS AND ANOTHER DEVELOPS OVER THE NORTHERN PLAINS...WITH ONLY A WEAK HIGH IN BETWEEN OVER THE CAROLINAS. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...WIND SWINGS AROUND TO THE SOUTH ON WEDNESDAY AS THE CENTER OF HIGH PRESSURE MOVES OFF THE COAST. NO REAL INCREASE IN WIND SPEED TO SPEAK OF HOWEVER SO SEAS MAY ACTUALLY CONTINUE TO SETTLE SOME FROM THEIR TUESDAY VALUES. A COLD FRONT WILL APPROACH FROM THE NW ON THURSDAY ALBEIT QUITE SLOWLY AS THE BOUNDARY WILL BE ALIGNED WITH ITS MID LEVEL STEERING FLOW. THE SLOW APPROACH OF THE FRONT WILL VEER THE WIND SLIGHTLY AND YIELD A GRADUAL INCREASE IN WIND SPEED. THIS WILL CONTINUE INTO THURSDAY NIGHT AT WHICH TIME SEAS WILL START RESPONDING TO THE INCREASED FLOW AND FETCH DURATION. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...43
AREA FORECAST DISCUSSION
NWS RALEIGH NC
647 AM EST SUN DEC 1 2013 .SYNOPSIS... HIGH PRESSURE REMAINS OVER THE REGION TODAY. LOW PRESSURE DEVELOPS ALONG THE CAROLINA COAST TONIGHT AND GRADUALLY STRENGTHENS AS IT MOVES AWAY FROM THE REGION MONDAY. HIGH PRESSURE THEN RETURNS FOR TUESDAY. && .NEAR TERM /THROUGH TODAY/... AS OF 300 AM SUNDAY... THE SURFACE RIDGE AXIS EXTENDED NORTHEAST TO SOUTHWEST ACROSS CENTRAL NORTH CAROLINA...WITH A SLACK GRADIENT IN PLACE. IN A FAST WESTERLY FLOW ALOFT...AS ONE MID-LEVEL SHORTWAVE EXITED CENTRAL NORTH CAROLINA TO THE EAST...ANOTHER WAS MOVING IN FROM THE TENNESEE VALLEY. THE 00Z RAOB ANALYSIS SHOWED GREATER 850MB AND 700MB MOISTURE JUST TO OUR SOUTH...AND SOME OF THIS MOISTURE HAS ADVECTED NORTH...TO ABOUT U.S. 64. THE NAM AND THE GFS ARE FAIRLY SIMILAR AND BOTH HAVE TRENDED DRIER CERTAINLY FROM THE PREVIOUS 00Z RUN...SUCH THAT THE MID LEVELS TEND TO BE FAIRLY DRY FOR MUCH OF THE DAY TODAY...WITH THE GREATEST MID-LEVEL MOISTURE OVER THE SOUTHERN COASTAL PLAIN RELATIVE TO THE REST OF CENTRAL NORTH CAROLINA. THE BEST 850MB LIFT IS CERTAINLY IN THE SOUTHEAST PART OF CENTRAL NORTH CAROLINA TODAY WHERE 850MB THETA-E ADVECTION IS GREATEST. FAINT RADAR RETURNS AND GUIDANCE FROM THE HRRR WRF SUGGEST A SMALL CHANCE OF SPRINKLES IN THE SANDHILLS AND SOUTHERN COASTAL PLAIN THIS MORNING...WITH A CHANCE OF RAIN MAINLY THIS AFTERNOON ALONG AND SOUTH OF A LINE FROM ABOUT KRWI TO KRCZ...WITH THE BEST CHANCE TOWARD KCTZ IN VICINITY OF GREATER MOISTURE AND LIFT. PRECIPITATION...IF ANY...SHOULD BE LIGHT...WITH THE GREATER PROBABILITY OF PLURAL HUNDREDTHS IN SAMPSON AND POSSIBLY INTO WAYNE COUNTIES AS OF THIS WRITING. 1000-850MB THICKNESSES WOULD SUPPORT WARMER TEMPERATURES THAN FORECAST BY ABOUT A CATEGORY...BUT A BLEND OF GUIDANCE WORKED WELL FOR SATURDAY HIGHS...AND WILL FOLLOW THE SAME FOR TODAY. FEWER AND THINNER CLOUDS NORTHWEST...MORE TOWARD THE SOUTHEAST BUT WITH HIGHER THICKNESSES AND MORE MOIST...RESULT IN A FAIRLY UNIFORM TEMPERATURE FORECAST IN THE LOWER TO POSSIBLY MID 50S. WINDS SHOULD BE LIGHT...WITH THE RELATIVELY GREATER SPEEDS TOWARD THE TRIAD...WHILE STILL UNDER 10KT...FROM THE SOUTHWEST...WEST OF THE SURFACE RIDGE AXIS. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... AS OF 300 AM SUNDAY... AGAIN THE NAM AND GFS ARE FAIRLY SIMILAR IN THE EVOLUTION OF THE SURFACE LOW ALONG THE COAST...WITH AN INVERTED TROUGH DEVELOPING EARLY TONIGHT FOLLOWED BY WEAK CYCLOGENESIS OVERNIGHT...THEN LOW PRESSURE GRADUALLY STRENGTHENING MONDAY AS IT MOVES AWAY FROM THE COASTAL CAROLINAS. 850MB LIFT IS NOT VERY STRONG OVERNIGHT INTO MONDAY AFTERNOON...WITH THE GFS IN PARTICULAR HAVING TRENDED FARTHER SOUTH WITH THE PASSAGE OF ITS MODERATE MID-LEVEL SHORTWAVE ACCOMPANYING THE MID-LEVEL TROUGH. JET SUPPORT ALSO LOOKS TO HAVE SHIFTED FARTHER SOUTH COMPARED TO RECENT RUNS. K INDICES ARE HIGHEST TOWARD THE COAST LATE TONIGHT AND MONDAY MORNING...BUT 850MB THETA-E STILL REMAINS MODEST WEST THROUGH THE COASTAL PLAIN...AND WITH THE WEAK LIFT AS LOW PRESSURE ORGANIZES JUST OFFSHORE...WILL CONTINUE AT LEAST A CHANCE OF RAIN EARLY TONIGHT MAINLY EAST OF INTERSTATE 95 WHEN OVERALL MOISTURE APPEARS HIGHEST FOR THE NIGHTTIME HOURS... THEN AGAIN MAINLY MONDAY MORNING ALONG AND EAST OF ABOUT U.S. 1 DURING A PERIOD OF A MODEST INCREASE IN MID-LEVEL MOISTURE IN CONJUNCTION WITH GOOD LOWER-LEVEL MOISTURE. FOR NOW WILL KEEP CHANCES BELOW LIKELY GIVEN THE DRIER MODEL TRENDS...NO MOS GUIDANCE IN CENTRAL NORTH CAROLINA CLOSE TO LIKELY...AND NAM AND GFS MODEL QPF BEING PRETTY LOW. PLAN TO KEEP THE TRIAD AND THE FAR WESTERN PIEDMONT DRY THIS PERIOD. 850MB THETA-E TROUGHINESS STARTS TO PUSH EAST MONDAY AFTERNOON WITH INCREASING SUBSIDENCE. BUFR SOUNDINGS ARE FAIRLY STABLE AND DRYING CERTAINLY BY 00Z TUESDAY...AND PRECIPITABLE WATER VALUES ARE AT OR BELOW A HALF-INCH MONDAY NIGHT. WILL NOTE CHANCES BELOW SLIGHT IN CENTRAL NORTH CAROLINA BY 00Z TUESDAY. LOWS TONIGHT AND HIGHS MONDAY ARE A LITTLE TRICKY GIVEN THE UNCERTAINTY SURROUNDING CLOUD COVER AND THE POTENTIAL VARIABLE THICKNESS OF SUCH CLOUD COVER. OPTED TO TRIM LOWS TONIGHT SLIGHTLY ESPECIALLY ALONG AND NORTH OF INTERSTATE 85 WHERE CLOUD COVER SHOULD BE LEAST AND THINNEST OVERNIGHT. GIVEN THE DRIER MODEL TREND OPTED TO RAISE MAXES INTO THE 50S THROUGHOUT CENTRAL NORTH CAROLINA MONDAY...STILL KEEPING THE WARMER READINGS OVER THE WESTERN PIEDMONT FOR NOW. OVERNIGHT LOWS MONDAY NIGHT NEAR THE COOLER MAV MOS GUIDANCE ANTICIPATING FEWER CLOUDS...LOWER TO MID 30S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 300 AM SUNDAY... WEAK HIGH PRESSURE WILL BUILD INTO THE REGION ON TUESDAY IN THE WAKE OF THE DEPARTING COASTAL CYCLONE AS A WESTERLY FLOW DEVELOPS ALOFT. FAIR WEATHER IS EXPECTED IN CENTRAL NC WITH A FEW LAYERS OF CLOUDS. HIGHS WILL RANGE IN THE LOWER 50S NORTHEAST TO NEAR 60 TOWARD THE SC BORDER. HEIGHTS BEGIN RISING ON WEDNESDAY AND THURSDAY AS A BROAD TROUGH DEVELOPS IN THE ROCKIES AND THE NORTHERN PLAINS. AN INCREASINGLY MOIST SOUTHERLY FLOW WILL PROMOTE AN INCREASE IN CLOUDINESS ON WEDNESDAY AND THURSDAY WITH WARMING TEMPERATURES ESPECIALLY ON THURSDAY. BOTH THE EC EFS AND THE GFS HIGHLIGHT A SHALLOW DISTURBANCE THAT WILL MOVE NORTHEAST ACROSS THE AREA ON WEDNESDAY THAT SHOWS UP AS A REGION OF ISENTROPIC UPGLIDE IN THE 290-295 LAYER. DON`T EXPECT ANY PRECIPITATION AT THIS TIME BUT HAVE INCREASED CLOUD PERCENTAGES DURING THE PERIOD. GFS BUFR SOUNDINGS ALSO SUGGEST THAT THERE COULD BE SOME GUSTY WINDS ON WEDNESDAY AFTERNOON WITH GUSTS UP TO 20-25 MPH AS MIXING TAPS INTO THE STRONGER FLOW ASSOCIATED WITH THE LOW LEVEL JET. A SLIGHTLY BETTER CHANCE OF RAIN ARRIVES IN THE NORTHWESTERN PORTION OF THE FORECAST AREA LATE THURSDAY AND ESPECIALLY THURSDAY NIGHT AS A COLD FRONT APPROACHES THE REGION FROM THE WEST. TEMPERATURES SHOULD WARM INTO THE MID 50S TO NEAR 60 ON ON WEDNESDAY AND THEN THE 60S TO NEAR 70 ON THURSDAY. DIFFERENCES IN THE GFS AND EC EFS BECOME MORE APPARENT ON FRIDAY AND ESPECIALLY SATURDAY WITH THE GFS BEING FASTER AND PUSHING THE FRONT THROUGH THE AREA LATE FRI/EARLY SAT WITH THE EC PERHAPS 12 HOURS SLOWER. WHILE THE BEST FORCING FOR ASCENT STAYS NORTH OF THE AREA...THE PLUME OF DEEP LAYER MOISTURE AND FORCING ASSOCIATED WITH THE FRONT SHOULD BE SUFFICIENT FOR CHC POPS. MILD TEMPERATURES ARE EXPECTED ON FRIDAY AHEAD OF THE FRONT AND AHEAD OF THE MAIN AREA OF RAIN. MAX TEMPS HAVE BEEN ADJUSTED UPWARD INTO THE UPPER 60S NORTHWEST TO NEAR 75 IN THE SOUTHEAST. ALSO ADJUSTED MIN TEMPS ON SATURDAY UPWARD TO ACCOUNT FOR THE CLOUDS AND MILD CONDITIONS AHEAD OF THE FRONT. MAX TEMPS ON SATURDAY WILL BE LIMITED GIVEN THE CLOUDS AND AREAS OF LIGHT RAIN BUT STILL EXPECT TEMPS TO REACH THE UPPER 50S NORTHWEST TO MID 60S SOUTHEAST. AT THIS POINT WE DON`T EXPECT ANY THUNDERSTORMS LATE FRIDAY INTO SATURDAY THUNDERSTORMS GIVEN THE MARGINAL MID LEVEL LAPSE RATES. && .AVIATION /12Z SUNDAY THROUGH THURSDAY/... AS OF 645 AM SUNDAY... MOSTLY VFR CONDITIONS WILL CONTINUE THROUGH THE 12Z VALID TAF PERIOD. AREAS OF MVFR CONDITIONS NEAR INTERSTATE 95...EVEN VERY BRIEFLY IFR AT KRWI...SHOULD END BY 14Z BASED ON TRENDS ON OBSERVATIONS AND THE SATELLITE FOG PRODUCT. MAINLY DURING THE AFTERNOON AND EVENING PATCHY LIGHT RAIN IS POSSIBLE SOUTH OF A LINE FROM ABOUT KFAY TO KRWI. THIS IS WHERE ANY THICKER CLOUDS SHOULD RESIDE DURING THAT TIME...THOUGH THEY ARE EXPECTED CURRENTLY TO HAVE THE HIGHEST PROBABILITY OF BEING VFR. WITH HIGH PRESSURE OVERHEAD... WINDS SHOULD BE SOMEWHAT VARIABLE. JUST ON THE WEST SIDE OF THE SURFACE RIDGE AXIS...WINDS SHOULD BE MORE SOUTHWEST TOWARD THE TRIAD. WINDS SHOULD TEND TO FAVOR NORTHERLY TOWARD KFAY. AT KRWI AND ESPECIALLY KRDU...THE LIGHT SURFACE WIND DIRECTION IS MORE CHALLENGING...BUT WILL CONTINUE TO LEAN WESTERLY DURING THE DAYLIGHT HOURS WITH THE CONSENSUS OF GUIDANCE BEING CONSISTENT IN SHOWING THAT DIRECTION...THOUGH IT COULD BE QUITE VARIABLE. BEYOND THE 12Z VALID TAF PERIOD...VFR CONDITIONS WILL BE FORECAST. AN ALTERNATIVE IS THE PROBABILITY OF SUB-VFR CONDITIONS OVERNIGHT INTO MONDAY MORNING IN CLOUDS AND PATCHY LIGHT RAIN ALONG AND EAST OF INTERSTATE 95...LEANING MVFR AS A CATEGORY IF IT OCCURS...WITH A CHANCE OF SUB-VFR CONDITIONS IN LIGHT FOG TOWARD THE TRIAD WHERE CLOUDS SHOULD BE LESSER AND THINNER. KRDU WILL BE IN BETWEEN...AND IT IS POSSIBLE FOR A PERIOD OF BOTH LIGHT FOG AND LOWER CLOUDS THERE BEFORE DRIER AIR AND SUBSIDENCE MOVE IN FROM THE WEST...CREATING WIDESPREAD VFR CONDITIONS ACROSS CENTRAL NORTH CAROLINA BY LATE MONDAY AFTERNOON. MVFR CONDITIONS IN FOG ARE POSSIBLE LATE MONDAY NIGHT AND EARLY TUESDAY...THEN AS MOISTURE INCREASES...THERE IS A CHANCE OF SUB-VFR CONDITIONS IN LOW CLOUDS TUESDAY NIGHT INTO WEDNESDAY...WITH GREATER CHANCES OF THOSE CONDITIONS CURRENTLY TOWARD THE TRIAD THOUGH POSSIBLE THROUGHOUT CENTRAL NORTH CAROLINA PARTICULARLY WEDNESDAY NIGHT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE && $$ SYNOPSIS...DJF NEAR TERM...DJF SHORT TERM...DJF LONG TERM...BLAES AVIATION...DJF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
650 AM CST SUN DEC 1 2013 .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 418 AM CST SUN DEC 1 2013 00Z/06Z MODELS ARE COMING MORE IN LINE TOWARD A GENERAL CONSENSUS SOLUTION...WITH THE GFS REMAINING A FAST OUTLIER. EVEN THE NAM IS SIMILAR TO THE CONSENSUS...JUST STRONGER. THE IDEA IS THAT AN UPPER LOW WILL DIG INTO THE NORTHWEST CONUS/NORTHERN ROCKIES...THEN EJECT INTO NORTHERN MINNESOTA BY 12Z WED. MODELS HAVE REMAINED CONSISTENT INDICATING 3 ROUNDS OF SNOWFALL. THE FIRST ROUND WILL BE LATER THIS AFTERNOON INTO TONIGHT. FORCING IS WEAK AND AVAILABLE MOISTURE IS RELATIVELY LOW...THINKING UP TO AN INCH OF SNOWFALL IS MOST LIKELY. THE SECOND WAVE (MONDAY INTO MONDAY NIGHT) IS STRONGER...WITH MORE AVAILABLE MOISTURE (PWATS APPROACHING 0.5 INCHES). MODELS INDICATE A DEFINED CIRCULATION AT 850MB (AND A WEAK 700MB LOW) PROPAGATING FROM NW ND INTO WESTERN MN ON MONDAY...LOSING DEFINITION MONDAY NIGHT AS IT PROPAGATES FURTHER TO THE EAST. ASSOCIATED WARM AIR ADVECTION/FRONTOGENESIS COMBINED WITH THE 0.5 INCH PWATS SHOULD LEAD TO A BAND OF SNOWFALL MOVING THROUGH THE REGION. MODELS INDICATE 0.20-0.40 INCHES QPF ACROSS ALL BUT THE NE FA...AND COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA OF 2-5 INCHES OF SNOW. MODELS INDICATE THAT THE MESOSCALE FORCING IS RELATIVELY WEAK...WHICH WOULD MEAN THE MODELS SHOULD BE IN THE BALL PARK WITH QPF. THE THIRD ROUND OF SNOWFALL (TUESDAY-TUESDAY NIGHT) WILL BE ASSOCIATED WITH THE MAIN STRONG MID-LEVEL LOW MOVING THROUGH THE REGION. THE 00Z ECMWF IS SLIGHTLY FASTER WITH THIS FEATURE. SYNOPTIC FORCING WILL BE VERY STRONG...WITH THE POTENTIAL FOR MESOSCALE BANDING. WITH THAT SAID...THIS ROUND OF SNOWFALL STILL HAS THE MOST UNCERTAINTY (DUE TO MODEL DIFFERENCES). GIVEN THE AVAILABLE MOISTURE (PWATS 0.5+ INCHES) AND STRONG FORCING EXPECTED...ALONG WITH THE SLOW MOVING NATURE OF THE SYSTEM...THIS ROUND SHOULD BRING 6+ INCHES (CURRENT THOUGHTS ARE 5 TO 10 INCHES) TO MOST AREAS. SOMETIME TOWARD THE TAIL END OF THE SNOWFALL...WINDS SHOULD INCREASE...LIKELY STRONG ENOUGH FOR BLOWING SNOW ISSUES. SINCE THE TRUE WINTER WARNING CONDITIONS WILL LIKELY NOT OCCUR UNTIL SOMETIME ON TUESDAY...WILL HOLD OFF ON ISSUING ANY WINTER HEADLINES. THIS WILL ALLOW FOR ANOTHER SET OF MODEL RUNS TO INCREASE CONFIDENCE. COULD SEE A SITUATION WHERE WE HAVE ADVISORY CONDITIONS ON MONDAY/MONDAY NIGHT FOLLOWED BY A SHORT BREAK...THEN WARNING CRITERIA SNOW TUESDAY/TUESDAY NIGHT (WITH WINDS AND BLOWING SNOW LATER TUESDAY NIGHT INTO WEDNESDAY). WILL ADD SOME DETAIL TO THE SPECIAL WEATHER STATEMENT AND HWO. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 418 AM CST SUN DEC 1 2013 WEDNESDAY-SATURDAY...BOTH THE GFS/ECMWF INDICATE SNOW WINDING DOWN ON WEDNESDAY AS THE SFC LOW PULLS AWAY. DESPITE A TREND TOWARDS A FASTER SOLUTION...THERE IS STILL SOME UNCERTAINTY WITH THE 00Z GEM SLOWER WITH THE SFC LOW...KEEPING SNOW AROUND THROUGH WEDNESDAY NIGHT. SOME LIGHT SNOW/SNOW SHOWERS COULD LINGER INTO LATE WEEK AS A REINFORCING UPPER LOW PIVOTS SOUTHWARD INTO THE REGION...MAINTAINING CYCLONIC FLOW. HOWEVER...THE MAIN CONCERN FOR THE REMAINDER OF THE WEEK WILL BE TEMPS AS A BITTERLY COLD ARCTIC AIR MASS TAKES UP RESIDENCE ACROSS THE NORTHERN PLAINS. BASED ON A MORE PROGRESSIVE SOLUTION...STRONG LOW-LEVEL COLD ADVECTION MAY PREVENT MUCH TEMPERATURE RISE ON WEDNESDAY. 1000-500 MB THICKNESSES FALL BELOW 500 DAM BY THURSDAY/FRIDAY...WITH HIGHS NO HIGHER THAN THE LOW SINGLE DIGITS. MODELS INDICATE THE SFC HIGH AXIS DOES NOT APPROACH UNTIL NEXT WEEKEND. THUS...WITH ONLY A GRADUAL SLACKENING OF THE PRESSURE GRADIENT...WINDS WILL REMAIN UP A BIT THROUGH THE WORK WEEK. THE COMBINATION OF WINDS AND BITTERLY COLD TEMPS LIKELY WILL LEAD TO DANGEROUS WIND CHILLS AT TIMES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 650 AM CST SUN DEC 1 2013 IFR CONDITIONS WILL LIKELY CONTINUE THROUGH THE MORNING HOURS...GRADUALLY RISING WITH DAYTIME HEATING (BUT NOT GREATER THAN MVFR CRITERIA). 10Z RAP GUIDANCE SHOWS THE POTENTIAL FOR A PERIOD OF VFR CONDITIONS TONIGHT AS LOW LEVEL FLOW INCREASES. THIS SEEMS LIKE A LOW PROBABILITY OF OCCURRENCE CONSIDERING THAT THE LOW-LEVEL AIRMASS IS EXPECTED TO REMAIN SATURATED. WILL MONITOR THE SITUATION AND ADJUST THE FORECASTS AS NEEDED. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SHORT TERM...TG LONG TERM...MAKOWSKI AVIATION...TG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
538 AM CST SUN DEC 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CST SUN DEC 1 2013 THE MAIN FOCUS IS ON THE INCREASING CHANCES FOR SNOW TONIGHT...MAINLY IN SOUTHEAST MINNESOTA...NORTHEAST IOWA AND FAR WESTERN WISCONSIN. CURRENTLY...NORTHWESTERLY FLOW ALOFT IS IN PLACE WITH A SURFACE RIDGE OF HIGH PRESSURE CENTERED ON THE EASTERN DAKOTAS. THE INITIAL QUESTION THIS MORNING IS WITH A STRATUS DECK THAT EXTENDS ACROSS NORTHERN WISCONSIN/MINNESOTA AND HOW FAR SOUTH IT WILL MAKE IT TODAY. THERE HAS NOT BEEN MUCH OF A SOUTHERLY PUSH WITH IT OVER THE PAST 6 HOURS OR SO...EXCEPT IN EASTERN WISCONSIN ALONG LAKE MICHIGAN. THE PAST FEW RUNS OF THE HRRR SHOW THIS STRATUS DECK HAVING TROUBLE MAKING IT SOUTH TODAY AS THE RIDGE OF HIGH PRESSURE COMES IN AND WEAKENS THE NORTHERLY SURFACE FLOW. IF THIS DECK DOES MAKE IT FURTHER SOUTH...IT WILL CAUSE TEMPERATURES TO BE ABOUT 5-10F COOLER FOR HIGHS. GOING INTO TONIGHT...A LEAD/WEAK MID LEVEL SHORT WAVE TROUGH WILL PROPAGATE EAST ACROSS THE NORTHERN PLAINS WHILE ISENTROPIC LIFT ON THE 290K SURFACE INCREASES. THIS SHOULD PROVIDE ENOUGH LIFT...ALBEIT WEAK...TO DEVELOP A BAND OF LIGHT SNOW FROM CENTRAL MINNESOTA DOWN ALONG THE MISSISSIPPI RIVER. ANY ACCUMULATIONS OVERNIGHT WILL BE ON THE LIGHT SIDE AT A FEW TENTHS OF AN INCH OR LESS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 335 AM CST SUN DEC 1 2013 LIFT AND MOISTURE WILL BECOME DEEPER MONDAY INTO WEDNESDAY AS THE CORE OF THE MID LEVEL TROUGH APPROACHES THE REGION. FOR MONDAY...THE MAIN FOCUS CONTINUES TO BE ALONG THE NOSE OF THE LOW LEVEL WARM AIR ADVECTION AND WHERE IT WILL SET UP. ALL OF THE 01.00Z GUIDANCE SHOW THE BAND OF PRECIPITATION EXPANDING THROUGH THE DAY AS THIS ADVECTION STRENGTHENS. HOWEVER...AS WARMER AIR COMES IN AT THE LOW LEVELS...SOME PRECIPITATION TYPE ISSUES ARISE WITH THE WARM LAYER POSSIBLY CAUSING THE SNOW TO CHANGE OVER TO RAIN. SURFACE TEMPERATURES SHOULD ALSO BE ON THE RISE ABOVE FREEZING...SO AM NOT EXPECTING ANY FREEZING RAIN AT THE MOMENT. THERE IS SOME UNCERTAINTY TOO WITH THE POSITION OF THE NORTHWEST TO SOUTHEAST SWATH OF PRECIPITATION WITH THE 01.00Z NAM/01.03Z SREF BEING THE FARTHEST NORTHEAST WHILE THE 01.00Z GFS/ECMWF DEVELOP IS MORE TO THE SOUTHWEST IN SOUTHEAST MINNESOTA/NORTHEAST IOWA. MAY BE UNDER-DOING THE SNOW AMOUNTS ON MONDAY...BUT THE POTENTIAL MIX HAS ME CAUTIOUS TO GO MUCH ABOVE A FEW TENTHS OF AN INCH. THE BIGGEST STORY WITH THE 01.00Z GUIDANCE IS HOW THEY HAVE ALL COME AROUND TO THIS THINKING OF A MUCH FASTER FRONTAL PASSAGE WITH THE DEEPENING SURFACE LOW/MID LEVEL TROUGH MOVING THROUGH EARLY ON WEDNESDAY. THE BEST CHANCES FOR ANY PRECIPITATION APPEARS TO BE FROM MONDAY NIGHT THROUGH WEDNESDAY AS THIS TROUGH APPROACHES. THE WARMER AIR COMING IN ON TUESDAY AHEAD OF THE SYSTEM SHOULD KEEP THE P-TYPE MAINLY AS RAIN UNTIL THE COLD FRONT COMES THROUGH EARLY ON WEDNESDAY. THE MAIN CHANCES FOR SNOW WILL BE ON MONDAY NIGHT AHEAD OF THE WARM AIR..AND THEN AGAIN ON WEDNESDAY MORNING BETWEEN THE LEAD COLD FRONT PASSAGE AND THE SECONDARY COLD FRONT WHICH USHERS IN THE DRASTICALLY COLDER AIR IN. OVERALL...CONFIDENCE IN GETTING ANY SPECIFIC DETAILS DOWN ON THE PRECIPITATION TRENDS IS PRETTY LOW...PARTICULARLY WITH THE SNOW AMOUNTS. IF ANY SNOW IS ABLE TO OCCUR WEDNESDAY MORNING AFTER THE FIRST FRONT COMES THROUGH...IT WILL MEAN THAT TEMPERATURES COULD BE COLDER THAN ADVERTISED GOING THROUGH THE REST OF THE WEEK. DUE TO THE FASTER FROPA...HAVE DROPPED THE PRECIPITATION CHANCES FROM THURSDAY INTO THE WEEKEND. AS FOR THE COLD SPELL...850MB TEMPERATURES ARE FORECAST TO DROP DOWN TO BETWEEN -15 TO -20C ON THURSDAY WITH THE POOL OF COLD AIR LASTING THROUGHOUT THE REGION PAST NEXT WEEKEND. EVEN IF THERE IS NO SNOW COVER DOWN ON THE GROUND...TEMPERATURES WILL BE MUCH BELOW NORMAL THROUGH THE FORESEEABLE FUTURE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 538 AM CST SUN DEC 1 2013 LOWER LEVEL MOISTURE/MVFR STRATUS DECK THAT WAS HEADED TOWARD THE AREA FROM NORTHERN MN/WI LAST EVENING HAS STALLED EARLY THIS MORNING...LOOKING TO STRUGGLE WITH THE DOWN-SLOPING NORTH/NORTHEAST FLOW FROM THE NORTHERN HIGHLAND TERRAIN OF WI. SFC-925MB WINDS FOR ANY ADVECTION OF THIS MOISTURE/CLOUDS BECOMES LIGHT/VARIABLE TODAY. HAVE LIMITED LOWER CLOUDS FOR TODAY TO SCT DIURNAL IN THE 2000-2500 FT RANGE DURING THE 17Z-22Z PERIOD. SFC/LOW LEVEL RIDGE AXIS PASSES THIS EVENING WITH LOWER LEVEL WARM ADVECTION/INCREASING 850-500MB MOISTURE SPREADING INTO THE AREA. CLOUD DECKS TO THICKEN/LOWER LATE THIS AFTERNOON/TONIGHT AS THE MOISTURE/SOME LIFTING ARRIVE. MODEL SIGNAL IS BECOMING MORE CONSISTENT THAT ENOUGH MOISTURE/LIFT WILL BE PRESENT FOR SOME -SN WEST OF THE MS RIVER LATER TONIGHT. ADDED A VCSH AFTER 05Z AT KRST FOR NOW AS APPEARS ANY LATE NIGHT -SN WOULD BE QUITE LIGHT. LEFT CIGS LATER TONIGHT VFR AS WELL...AS BULK OF THE MOISTURE/CLOUD INCREASE AND LIFTING IS ABOVE 850MB. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM....HALBACH AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
337 AM MST SUN DEC 1 2013 .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 337 AM MST SUN DEC 1 2013 WEATHER PATTERN CHANGE BEGINNING TO START TODAY. FORECAST CHALLENGES DEAL WITH A HIGH WIND EVENT STARTING TODAY AND PERSISTING THROUGH TUESDAY MORNING. CURRENTLY...CONDITIONS ARE PRETTY QUIET SO FAR THIS MORNING. SKIES ARE MOSTLY CLEAR WITH FAIRLY LIGHT WINDS OUTSIDE THE WIND PRONE AREAS. TEMPERATURES QUITE WARM WITH MAINLY MID TO UPPER 30S BEING REPORTED. WINDS SO FAR AT OUR WIND PRONE AREAS ARE GUSTING IN THE UPPER 30S TO LOW 40S AND ARE EXPECTED TO CONTINUE INCREASING AS THE MORNING PROGRESSES. TO THE NORTHWEST OVER WASHINGTON STATE...OUR NEXT WINTER STORM COMING ONSHORE OVER SOUTHERN BRITISH COLUMBIA AND WASHINGTON. FOR TODAY...THE HIGH WIND EVENT IS STILL ON TRACK WITH LATEST WRKHGT PRODUCT SHOWING CRAIG TO CASPER 850 AND 700MB HEIGHT GRADIENTS INCREASING TO NEAR 60MTRS BY 18Z TODAY. THESE GRADIENTS EXPECTED TO CONTINUE INCREASING THIS AFTERNOON AND OVERNIGHT TO NEARLY 84 MTRS AT 850MBS AND 81 MTRS AT 700MB BY 12Z MONDAY. THIS IS GOING TO BE A PRETTY IMPRESSIVE HIGH WIND EVENT AS WE DO NOT NORMALLY SEE THESE TYPES OF GRADIENTS WITH OUR NORMAL RUN OF THE MILL HIGH WIND EVENTS. WENT AHEAD AND STARTED THE WIND PRONE AREAS OF SOUTHEAST WYOMING IN WIND WARNING CRITERIA BY 18Z TODAY. LATEST MOS GUIDANCE SHOWING RAWLINS AND LARAMIE INCREASING IN WINDS TODAY THROUGH THE LATE AFTERNOON AND OVERNIGHT. WENT AHEAD WITH A HIGH WIND WARNING FOR CARBON AND ALBANY COUNTIES BEGINNING AT 7 PM THIS EVENING. KEPT CONVERSE AND LARAMIE COUNTIES IN THE HIGH WIND WATCH FOR NOW. DAY SHIFT CAN TAKE ANOTHER LOOK TO UPGRADE AND/OR EXPAND FURTHER EAST LATER TODAY. LOOKS LIKE WE ARE GOING TO NEED SOMETHING FOR THE PANHANDLE AS 850MB WINDS INCREASE TO 45 KNOTS MONDAY MORNING. ONE LAST THING FOR TODAY IS THE SNOWY AND SIERRA MADRE RANGES. QPF OUTPUT PRETTY MEAGER FOR THESE TWO ZONES TODAY. STILL THINK THE OUTPUT IS UNDERDONE...BUT WILL DEFER TO THE DAY SHIFT. DID GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW. IF LATER SHIFTS SEE QPF AMOUNTS INCREASING...WE MAY NEED TO ISSUE A SHORT FUSED WINTER STORM WARNING OUT THAT WAY. 700MB WINDS FOR MONDAY VERY IMPRESSIVE WITH THE 12Z GFS FORECASTING 70 TO 75KTS AT 06Z TONIGHT AND LASTING THROUGH 06Z TOMORROW NIGHT AHEAD OF THE APPROACHING COLD FRONT. LOOKS LIKE THE FRONT MOVES INTO CONVERSE COUNTY LATE MONDAY EVENING AND THROUGH THE CHEYENNE AREA/SOUTHERN PANHANDLE BY 12Z TUESDAY. PROBABLY WILL NOT SEE MUCH IN THE WAY OF SNOW EAST OF THE LARAMIE RANGE UNTIL THE WINDS SWITCH TO THE NORTHEAST BEHIND THE FRONT LATER TUESDAY MORNING. VERY COLD 700MB TEMPERATURES BEHIND THE FRONT AS WELL...DROPPING FROM 0C MONDAY AFTERNOON...TO -18C TUESDAY AFTERNOON. GOT A CALL FROM AN AREA RANCHER OVERNIGHT. THEY ARE IN THE MIDDLE OF CALVING SEASON. PASSED ON THAT THEY PROBABLY WANT TO GET THEIR CATTLE SHELTERED BEFORE TUESDAY AFTERNOON AS TEMPERATURES ARE GOING TO BE SHARPLY DROPPING AND WIND CHILLS FALL WELL BELOW ZERO TUESDAY NIGHT. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 337 AM MST SUN DEC 1 2013 00Z MODELS ARE IN FAIR AGREEMENT WITH THE LARGER SCALE SYNOPTIC PATTERN AS THE DEEP UPPER TROUGH DIGS INTO THE WESTERN CONUS TUESDAY NIGHT AND WEDNESDAY. A POTENT SHORTWAVE AT THE BOTTOM OF THE TROUGH LOOKS TO MOVE ACROSS UT/NV AND INTO CO ON WEDNESDAY WITH SFC CYCLOGENESIS OCCURRING OUT AHEAD OF THE WAVE. THE LOW CENTER IS PROGGED TO BE OVER SOUTHWESTERN CO BY 18Z WEDNESDAY WITH AN INVERTED TROUGH DEVELOPING ALONG THE ROCKIES. THIS COULD DO TWO THINGS. FIRST IT COULD INCREASE NORTHEASTERLY WINDS AND THEREFORE UPSLOPE FORCING ALONG THE LARAMIE RANGE DEPENDING WHERE EXACTLY THE INVERTED TROUGH SETS UP. SECOND...IT COULD HOLD BACK THE SURGE OF ARCTIC AIR OVER THE MOUNTAINS UNTIL LATER IN THE PERIOD. WITH SOME UNCERTAINTY YET IN THIS SCENARIO...DID NOT MAKE ANY DRASTIC CHANGES TO THE ONGOING FORECAST FOR POPS...WINDS AND TEMPS THROUGH WEDNESDAY. KEPT HIGHER POPS OVER THE HIGH COUNTRY WHERE THE STRONGER PVA AND POTENTIAL NORTHEASTERLY UPSLOPE COULD BE MAXIMIZED. PLENTY OF MOISTURE LOOKS TO MOVE UP WITH THE SHORTWAVE SO IF THIS SCENARIO IS REALIZED...SNOW WILL BE WIDESPREAD OVER THIS AREA AND COULD SEE MODERATE RATES AT TIMES. ONE CAVEAT IS THAT VERY COLD TEMPS COULD LIMIT ACCUMULATION OVERALL DUE TO A FINER SNOW TYPE. FURTHER EAST...BROADSCALE LIFT AHEAD OF THE UPPER WAVE WILL BRING A GOOD CHANCE FOR SNOW THROUGH WEDNESDAY AND WEDNESDAY NIGHT...ESPECIALLY FOR THE SOUTHERN HALF OF THE CWA. SNOW WILL STEADILY DIMINISH FROM NORTH TO SOUTH THURSDAY BUT MODELS SHOW SOME LINGERING LIGHT QPF THROUGH THURSDAY. THIS SUGGESTS LIGHT SNOW/FLURRIES WILL PERSIST AT TIMES AS THE ARCTIC HIGH MAKES A STRONGER PUSH TOWARD THE FORECAST AREA AND INDUCES WEAK UPSLOPE FLOW IN A VERY COLD AIRMASS. SKIES SHOULD BEGIN TO CLEAR THURSDAY NIGHT WHICH WILL ALLOW TEMPS TO PLUMMET WELL BELOW ZERO ACROSS THE MAJORITY OF THE FORECAST AREA. HOWEVER...ANY LINGERING CLOUD COVER WILL IMPACT JUST HOW LOW TEMPS WILL FALL OVERNIGHT. FRIDAY WILL REMAIN VERY COLD UNDER 700 MB TEMPS OF MINUS 20 TO MINUS 26...AND LIGHT SNOW/FLURRIES COULD VERY WELL CONTINUE IN THIS FRIGID ENVIRONMENT. ANOTHER SHORTWAVE WILL APPROACH FROM THE WEST ON SATURDAY AND WILL REINFORCE THE COLD AIRMASS AND POTENTIAL FOR LIGHT SNOW ACROSS THE CWA. SO AS IT STANDS...LOOKS LIKE THIS WILL BE A LONG DURATION COLD SPELL...WHICH WILL HAVE A HIGH IMPACT ON LIVESTOCK AND ANY PERSONS PLANNING OUTDOOR RECREATION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY MORNING) ISSUED AT 1027 PM MST SAT NOV 30 2013 SCATTERED TO BROKEN MID LEVEL CLOUDS WILL PREVAIL TONIGHT...WITH MVFR TO IFR CIGS DEVELOPING OVER WESTERN AND SOUTHERN CARBON COUNTY BY DAYBREAK SUNDAY. NAM MOS AND HRRR HAVE BEEN CONSISTENT WITH AT LEAST IFR CIGS INVOF KRWL AND KSAA AIRFIELDS. KEPT PREVAILING BKN015 THROUGH SUNDAY AFTERNOON AT KRWL. SNOW SHOWERS WILL DEVELOP AND OBSCURE THE SNOWY AND SIERRA MTNS SUNDAY. IT WILL BE BREEZY TO WINDY SUNDAY WITH WESTERLY WINDS POSSIBLY GUSTING AS HIGH AS 50 KT FOR THE WIND CORRIDORS OF SOUTHEAST WY. GUSTS TO 35 KT ARE EXPECTED ELSEWHERE...EXCEPT 25 KT IN WESTERN NEBRASKA. && .FIRE WEATHER... ISSUED AT 337 AM MST SUN DEC 1 2013 WIDESPREAD HIGH WIND EVENT STILL ON TRACK TO BEGIN IMPACTING THE AREA STARTING LATE THIS MORNING AND PERSISTING THROUGH TUESDAY MORNING. WINDS INITIALLY INCREASING IN OUR SOUTHEAST WYOMING WIND PRONE AREAS...BUT THEN SPREADING OUT TO OTHER AREAS LATER THIS AFTERNOON AND TONIGHT. THIS IS ALL DUE TO A PACIFIC LOW PRESSURE SYSTEM TRACKING INTO MONTANA TODAY. THIS LOW WILL DRAGS A COLD FRONT THROUGH THE AREA MONDAY AFTERNOON WITH WINDS SHIFTING FROM WEST TO NORTHEAST BEHIND THE FRONT. WIDESPREAD ACCUMULATING SNOW AND BITTERLY COLD TEMPERATURES BEHIND THE FRONT FOR MOST AREAS TUESDAY AND ON THROUGH THE WEEK. SNOW ENDING FOR MOST LOCATIONS BY THURSDAY...BUT EXTREME COLD TEMPERATURES PERSISTING INTO THE WEEKEND. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 11 AM MST MONDAY FOR WYZ112-114. HIGH WIND WARNING FROM 11 AM THIS MORNING TO 5 AM MST TUESDAY FOR WYZ106-107-110-116-117. HIGH WIND WATCH FROM THIS EVENING THROUGH LATE MONDAY NIGHT FOR WYZ101-118. HIGH WIND WARNING FROM 7 PM THIS EVENING TO 5 AM MST TUESDAY FOR WYZ104-105-109-115. NE...NONE. && $$ SHORT TERM...CLAYCOMB LONG TERM...RJM AVIATION...JAMSKI FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS TAUNTON MA
430 PM EST SUN DEC 1 2013 .SYNOPSIS... AN OCEAN STORM WILL LIKELY PASS FAR ENOUGH OFFSHORE TO BRING SCATTERED RAIN SHOWERS MON NIGHT/TUE ACROSS THE COASTAL PLAIN. HIGH PRESSURE AND RELATIVELY MILD WEATHER WILL PUSH IN WED AND THU. A STRONG COLD FRONT WILL APPROACH DURING FRIDAY BRINGING A CHANCE FOR PRECIPITATION...THEN PROGRESSIVELY COLDER AIR WORKS IN NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 425 PM UPDATE... LATEST SURFACE MAP ALREADY SHOWING THE TRANSFER OF ENERGY FROM A WEAK LOW PRESSURE IN THE LOWER GREAT LAKES TO A LOW PRESSURE OFF THE MID ATLANTIC COAST. THIS LOW PRESSURE JUST OFF THE COAST WILL SUPPLY JUST ENOUGH LIFT TO KEEP SHOWERS GOING ACROSS PORTIONS OF EASTERN MA AND RI. THE HRRR HAD A GOOD HANDLE ON THESE LIGHT SHOWERS...AND WAS LEANED ON HEAVILY FOR UPDATING THE FORECAST THIS AFTERNOON. THE GOOD NEWS IS TEMPERATURES ARE ABOVE FREEZING...SO NOT EXPECTING ANY MORE FREEZING DRIZZLE OR FREEZING RAIN. ISOLATED LOW-TOPPED CONVECTION DEVELOPED NEAR THE ENTRANCE TO NARRAGANSETT BAY. THE MAIN THREAT WILL BE FOR BRIEF TORRENTIAL RAINFALL. WE DID HAVE A REPORT FROM SOUTH KINGSTOWN RI OF PEA- SIZED HAIL...A TESTAMENT TO NEARNESS OF COLDER AIR TO THE GROUND. LATER TONIGHT...THE WEAK OFFSHORE LOW PRESSURE WILL CONTINUE TO MOVE INTO THE GULF OF MAINE. THIS SHOULD BRING AN END TO MOST OF THE PRECIPITATION ACROSS SOUTHERN NEW ENGLAND BEFORE CHANGING PRECIPITATION TYPES BECOME A CONCERN. LOW-LEVEL MOISTURE SHOULD LEAD TO AREAS OF FOG TONIGHT... ESPECIALLY AFTER MIDNIGHT. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... SOUTHERN NEW ENGLAND IS IN BETWEEN A PAIR OF LOW PRESSURES MONDAY. THE FIRST WILL BE A LOW PRESSURE MOVING TOWARD THE MARITIMES...THE OTHER WILL BE A STRONGER LOW PRESSURE OFF THE MID ATLANTIC COAST. THIS SHOULD MEAN A SLIGHT CHANCE OF SHOWERS TOWARD THE EAST COAST OF MA DURING THE MORNING...WITH ANOTHER CHANCE OF SHOWERS ACROSS RI AND SOUTHEAST MA DEVELOPING FROM THE SOUTH DURING LATE AFTERNOON INTO MONDAY NIGHT. TIMING AND TEMPERATURES INDICATE RAIN SHOULD BE THE DOMINANT PRECIPITATION TYPE. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGHLIGHTS... * SCATTERED SHOWERS POSSIBLE TUE ACROSS COASTAL AREAS * DRY AND MILDER WED INTO THU WITH SPOTTY SHOWERS POSSIBLE * COLD FRONT MAY BRING PERIOD OF PRECIPITATION THU NIGHT-FRI...THEN COLDER TEMPERATURES RETURN NEXT WEEKEND OVERVIEW... UPPER LEVEL PATTERN EVOLVES FROM BROAD TROUGHING TO AN EVENTUAL CUTOFF H5 LOW BUT WELL E OF NEW ENGLAND TUE-WED. MEDIUM RANGE MODELS CONTINUE TO SIGNAL LONG WAVE TROUGH DIVING INTO THE WESTERN U.S. WITH TEMPS RUNNING AT LEAST 20 DEGREES BELOW SEASONAL NORMALS ACROSS THE PLAINS BY LATE WEEK. THIS WILL TRANSLATE TO A BROAD RIDGE BUILDING OVER THE EAST AS WELL AS A SURGE OF SOMEWHAT MILDER TEMPS. WITH TWO LARGE CUTOFF LOWS SPINNING ACROSS CANADA...COLD AIR APPEARS TO MIGRATE S AND E WHILE UPPER RIDGE BUILDS OFFSHORE LATER FRIDAY INTO NEXT WEEKEND. SO...AFTER BRIEF WARMUP...APPEARS ANOTHER SURGE OF COLD AIR WILL START TO WORK INTO THE REGION LATER SAT/NEXT SUN...FOR NOW. DETAILS... TUESDAY...BACK EDGE OF PRECIP LINGER ACROSS COASTAL AREAS AS LOW PRES PASSES WELL SE OF NANTUCKET DURING THE DAY. HAVE KEPT CHANCE POPS GOING THERE...THOUGH SHOULD BE ENDING FOR MOST AREAS EXCEPT THE CAPE AND ISLANDS DURING THE DAY. LEFTOVER CLOUDS SHOULD START TO CLEAR DURING THE AFTERNOON. TEMPS WILL TOP OFF IN THE 40S. TUESDAY NIGHT-WEDNESDAY...WEAK HIGH PRES RIDGE STEADILY CROSSES THE REGION DURING THIS TIMEFRAME. EXPECT OVERNIGHT LOWS IN THE MID 20S WELL INLAND TO THE MID-UPPER 30S ALONG THE IMMEDIATE COAST. ON WED...CLOUDS WILL BEGIN TO PUSH E DURING THE AFTERNOON. HIGHS WILL AGAIN BE IN THE 40S. WEDNESDAY NIGHT...WARM FRONT APPROACHES WHICH MAY BRING SOME LIGHT RAIN SHOWERS OR POSSIBLY SOME LIGHT FREEZING RAIN ACROSS S NH/N CENTRAL AND NW MA TO BEGIN EARLY WED NIGHT. LOWS IN THE UPPER 20S TO UPPER 30S EARLY WILL RISE THROUGH THE OVERNIGHT. THURSDAY-FRIDAY...COLD FRONT SLOWLY SLIDES THROUGH THE REGION DURING THU INTO THU NIGHT AS IT RUNS CLOSE TO PARALLEL TO THE W-SW UPPER FLOW. THE FRONT APPEARS TO STALL THU NIGHT INTO FRIDAY WITH ANOTHER WAVE OF LOW PRES MOVING ALONG IT. THIS WILL BRING RENEWED CHANCE FOR PRECIP. LOOKS LIKE IT WILL MAINLY BE IN THE FORM OF RAIN. MAY SEE BRIEF PERIOD OF FREEZING RAIN LATE THU NIGHT INTO FRI MORNING OVER HIGHER TERRAIN OF S NH AS TEMPS TRY TO FALL AT OR SLIGHTLY BELOW FREEZING. FRIDAY NIGHT-SUNDAY...MODELS TRY TO MOVE ANOTHER SHORT WAVE IN THE ELONGATED UPPER FLOW THAT MAY TRY TO FLATTEN OUT AS UPPER CUTOFF LOWS ACROSS CENTRAL AND EASTERN CANADA PUSH SURGE OF COLD AIR INTO THE REGION. TIMING IS STILL IN QUESTION...SO CONTINUED LOW CONFIDENCE WITH THIS PORTION OF THE FORECAST. DOES LOOK LIKE PERIOD OF PRECIP WILL CONTINUE INTO SAT...BUT MORE QUESTIONS AS TO PTYPE DURING THE FRI NIGHT INTO EARLY SAT TIMEFRAME. FOR NOW...HAVE TENDED TO DRY THINGS OUT DURING SAT BUT WILL TURN COLDER ESPECIALLY ON SUNDAY. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY NIGHT/...MODERATE CONFIDENCE IN TAFS. LOW CONFIDENCE IN EXACT TIMING. THROUGH 00Z...A MIX OF CONDITIONS WILL PERSIST THROUGH HIS AFTERNOON...RANGING FROM VFR...TO IFR ACROSS THE MONADNOCKS OF NH...THE CENTRAL WORCESTER HILLS...AND THE HIGHER TERRAIN OF NORTHERN CT. LOW LEVEL RH IS STILL RATHER HIGH...SO EXPECTING CIGS TO CRASH FOR BRIEF PERIOD THIS EVENING...ESPECIALLY ACROSS EASTERN MA...INCLUDING KBOS. TONIGHT...ONSHORE FLOW WILL ALLOW FOR VFR/MVFR CIGS TO DROP OVERNIGHT TO LOW END MVFR/IFR. EXPECTING FOG TO DEVELOP AT THE USUAL LOCATIONS...CAUSING SOME VSBYS RESTRICTIONS. LIGHT OFFSHORE WINDS SHOULD DEVELOP...AND SHOULD KEEP MORE WIDESPREAD FOG FROM DEVELOPING ACROSS EASTERN MA AND RI. SHOULD THESE WINDS NOT DEVELOP AS EXPECTED...MORE WIDESPREAD FOG SHOULD RESULT. IFR TOWARD THE COAST...WITH VFR FARTHER INLAND. TOMORROW...CONDITIONS SLOWLY IMPROVE TO VFR ACROSS ALL AREAS. PATCHY DRIZZLE TO START THE DAY ACROSS EASTERN MA. MONDAY NIGHT...MAINLY MVFR TO VFR CONDITIONS. LOWER CONDITIONS MOST LIKELY TOWARD THE COAST WHERE THE BEST CHANCE FOR A RAIN SHOWER WILL EXIST. KBOS TAF...MODERATE CONFIDENCE...MAINLY DUE TO TIMING ISSUES. FOG COULD BE MORE WIDESPREAD IF OFFSHORE WIND DO NOT DEVELOP AS STRONGLY AS CURRENT EXPECTATIONS. LOWER VSBYS AND CIGS WOULD RESULT OTHERWISE. CIGS LESS THAN 1000 FEET CLOSE TO TERMINAL NOW. HAVE HIGHER CONFIDENCE LOWER CIGS WILL IMPACT KBOS THIS EVENING. ALSO SPED UP TIMING FOR LOWER CIGS TO ARRIVE. KBDL TAF...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN TIMING. OUTLOOK...TUESDAY THROUGH FRIDAY...MODERATE CONFIDENCE. TUESDAY...MAINLY VFR CONDITIONS ACROSS CENTRAL AND WESTERN AREAS. MVFR CIGS/VSBYS WITH BRIEF IFR CONDITIONS POSSIBLE ALONG COASTAL AREAS ESPECIALLY THROUGH MIDDAY...THEN SHOULD IMPROVE DURING THE AFTERNOON. MAINLY VFR TUE NIGHT. WEDNESDAY...MAINLY VFR DURING THE DAY. MAY SEE MVFR CIGS/VSBYS DEVELOP FROM W-E WED NIGHT. WEDNESDAY NIGHT-THURSDAY NIGHT...LOW END VFR CONDITIONS WITH PERIODS OF MVFR-IFR IN SCT SHOWERS. MAY SEE BRIEF PERIOD OF -FZRA BOTH LATE WED NIGHT AND THU NIGHT ACROSS HIGHER TERRAIN OF S NH POSSIBLY INTO N CENTRAL AND NW MA. FRIDAY...MAINLY MVFR CIGS/VSBYS IN SHOWERS DURING THE DAY. MAY SEE BRIEF PERIOD OF IFR CONDITIONS FRI NIGHT AS PRECIP BEGINS TO MIX AS COLDER AIR MOVES IN ACROSS S NH/N MA. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE. CONDITIONS WILL BE BELOW SMALL CRAFT ADVISORY LEVELS THROUGH THIS PERIOD. DRIZZLE AND FOG WILL BE THE MAIN CONCERN TONIGHT INTO MONDAY...WHICH COULD LOWER VISIBILITIES. OUTLOOK...TUESDAY THROUGH FRIDAY... TUESDAY...MODERATE TO HIGH CONFIDENCE. OCEAN STORMS PASSES WELL SE OF NANTUCKET...BUT WILL STILL SEE NE WINDS GUSTING TO 25 KT ACROSS THE EASTERN OUTER WATERS. SEAS WILL ALSO BUILD...UP TO 5-8 FT MAINLY OVER THE OUTER WATERS. WEDNESDAY...WINDS BACK TO NW AND START TO DIMINISH. MAY SEE SOME GUSTS TO 25 KT. SEAS WILL REMAIN ABOVE SMALL CRAFT CRITERIA...THOUGH SHOULD SUBSIDE DURING WED NIGHT. THURSDAY-FRIDAY...EXPECT WINDS BELOW SMALL CRAFT CRITERIA. SEAS MAY LINGER AROUND 5 FT ON THE OUTER WATERS. && .TIDES/COASTAL FLOODING... ASTRONOMICAL TIDES ARE QUITE HIGH TUESDAY MORNING...WITH AN 11.9 HIGH TIDE IN BOSTON. FORTUNATELY...IT LOOKS LIKE AN OCEAN STORM WILL INTENSIFY TOO FAR EAST AND TOO LATE FOR A SIGNIFICANT COASTAL FLOOD EVENT. HOWEVER...THE POTENTIAL FOR SPLASHOVER AND POCKETS OF VERY MINOR COASTAL FLOODING ACROSS THE EASTERN MA COAST STILL EXISTS GIVEN THE HIGH ASTRONOMICAL TIDES. IN ADDITION...MINOR BEACH EROSION IS ALSO A POSSIBILITY DURING THE TUESDAY HIGH TIDE CYCLES ALONG THE OUTER CAPE OCEAN SIDE AND THE EAST SHORE OF NANTUCKET. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/EVT NEAR TERM...BELK SHORT TERM...BELK LONG TERM...EVT AVIATION...BELK/EVT MARINE...BELK/EVT TIDES/COASTAL FLOODING...STAFF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
239 PM EST SUN DEC 1 2013 .SYNOPSIS... A CLIPPER LOW TODAY WILL BRING A CHANCE OF LIGHT MIXED WINTRY PRECIPITATION. AN OCEAN STORM WILL LIKELY PASS FAR ENOUGH EAST OF OUR REGION TO JUST BRING THE RISK FOR A PERIOD OF RAIN SHOWERS MON NIGHT/TUE...MAINLY ON THE COASTAL PLAIN. RELATIVELY MILD WEATHER WED/THU WILL BE REPLACED BY MUCH COLDER WEATHER SOMETIME FRI OR SAT...ALONG WITH THE POTENTIAL FOR A PERIOD OF PRECIPITATION. && .NEAR TERM /THROUGH TONIGHT/... 200 PM UPDATE... LATEST SURFACE MAP ALREADY SHOWING THE TRANSFER OF ENERGY FROM A WEAK LOW PRESSURE IN THE LOWER GREAT LAKES TO A LOW PRESSURE OFF THE MID ATLANTIC COAST. THIS LOW PRESSURE JUST OFF THE COAST WILL SUPPLY JUST ENOUGH LIFT TO KEEP SHOWERS GOING ACROSS PORTIONS OF EASTERN MA AND RI. THE HRRR HAD A GOOD HANDLE ON THESE LIGHT SHOWERS...AND WAS LEANED ON HEAVILY FOR UPDATING THE FORECAST THIS AFTERNOON. THE GOOD NEWS IS TEMPERATURES ARE ABOVE FREEZING...SO NOT EXPECTING ANY MORE FREEZING DRIZZLE OR FREEZING RAIN. LATER TONIGHT...THE WEAK OFFSHORE LOW PRESSURE WILL CONTINUE TO MOVE INTO THE GULF OF MAINE. THIS SHOULD BRING AN END TO MOST OF THE PRECIPITATION ACROSS SOUTHERN NEW ENGLAND BEFORE CHANGING PRECIPITATION TYPES BECOME A CONCERN. LOW-LEVEL MOISTURE SHOULD LEAD TO AREAS OF FOG TONIGHT... ESPECIALLY AFTER MIDNIGHT. .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... SOUTHERN NEW ENGLAND IS IN BETWEEN A PAIR OF LOW PRESSURES MONDAY. THE FIRST WILL BE A LOW PRESSURE MOVING TOWARD THE MARITIMES...THE OTHER WILL BE A STRONGER LOW PRESSURE OFF THE MID ATLANTIC COAST. THIS SHOULD MEAN A SLIGHT CHANCE OF SHOWERS TOWARD THE EAST COAST OF MA DURING THE MORNING...WITH ANOTHER CHANCE OF SHOWERS ACROSS RI AND SOUTHEAST MA DEVELOPING FROM THE SOUTH DURING LATE AFTERNOON INTO MONDAY NIGHT. TIMING AND TEMPERATURES INDICATE RAIN SHOULD BE THE DOMINANT PRECIPITATION TYPE. && .LONG TERM /TUESDAY THROUGH SATURDAY/... HIGHLIGHTS... * PERIOD OF RAIN SHOWERS POSSIBLE MAINLY COASTAL PLAIN TUE * MILDER WED/THU WITH JUST THE RISK OF A SPOT SHOWER OR TWO * TURNING COLDER SOMETIME FRI INTO SAT WITH A PERIOD OF PRECIPITATION POSSIBLE DETAILS... TUESDAY...LATEST MODELS ARE IN FAIRLY GOOD AGREEMENT IN LOW PRESSURE EMERGING OFF THE CAROLINA COAST AND INTENSIFYING INTO A STRONG OCEAN STORM. IT APPEARS THOUGH THAT THE SYSTEM WILL TRACK TOO FAR EAST AND INTENSIFY TOO LATE FOR A SIGNIFICANT IMPACT IN SOUTHERN NEW ENGLAND. THEREFORE...JUST EXPECT A GLANCING BLOW WITH THE POTENTIAL FOR A PERIOD OF RAIN SHOWERS MAINLY ALONG THE COASTAL PLAIN. IF SOME OF THE PRECIPITATION WERE TO REACH INTO THE DISTANT INTERIOR...IT MAY BE COLD ENOUGH FOR A BIT OF SNOW. HOWEVER...LATEST GUIDANCE SUGGEST THAT THE STEADY PRECIP MAY BE CONFINED TO THE COASTAL PLAIN...BUT TOO EARLY TO COMPLETELY RULE OUT THAT POSSIBILITY. HIGHS SHOULD GENERALLY BE IN THE 40S ON TUESDAY WITH AN ABUNDANCE OF CLOUDS. WEDNESDAY AND THURSDAY... MOST OF THIS TIME WILL PROBABLY END UP DRY...BUT A WEAK SHORTWAVE MOVING THROUGH IN WESTERLY FLOW ALOFT MAY TRIGGER A FEW SPOT SHOWERS SOMETIME LATE WED OR THU. RISING HEIGHT FIELDS AHEAD OF A DIGGING UPPER LEVEL TROUGH IN THE CENTRAL U.S. WILL YIELD RELATIVELY MILD WEATHER. HIGHS SHOULD GENERALLY BE IN THE 40S TO LOWER 50S. FRIDAY AND SATURDAY... A VERY LOW CONFIDENCE FORECAST OVER THIS TIME. A STRONG COLD FRONT WILL BE APPROACHING THE REGION...AS A COUPLE WAVES OF LOW PRESSURE RIDE ALONG IT. DEPENDING ON HOW QUICKLY THE FRONT SAGS SOUTH AND WHERE WE END UP IN RELATION TO THE WAVES OF LOW PRESSURE...WILL DETERMINE OUR WEATHER. WE DO KNOW THAT IT WILL EVENTUALLY TURN COLDER...BUT WHEN THAT OCCURS IS HIGHLY UNCERTAIN. WE ALSO WILL PROBABLY DEAL WITH A PERIOD OF WET WEATHER. ITS ALSO NOT OUT OF THE QUESTION THAT SOME OF THE AREA ENDS UP WITH A BIT OF WINTRY PRECIPITATION AT THE END. THIS WOULD OCCUR IF THE BOUNDARY HANGS UP TO OUR SOUTH AND ANOTHER WAVE OF LOW PRESSURE DEVELOPS ON IT. AGAIN THOUGH VERY LOW CONFIDENCE ON HOW THINGS EVOLVE IN THIS TIME PERIOD. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY NIGHT/...MODERATE CONFIDENCE IN TAFS. LOW CONFIDENCE IN EXACT TIMING. THROUGH 00Z...A MIX OF CONDITIONS WILL PERSIST THROUGH HIS AFTERNOON...RANGING FROM VFR...TO IFR ACROSS THE MONADNOCKS OF NH...THE CENTRAL WORCESTER HILLS...AND THE HIGHER TERRAIN OF NORTHERN CT. TONIGHT...ONSHORE FLOW WILL ALLOW FOR VFR/MVFR CIGS TO DROP OVERNIGHT TO LOW END MVFR/IFR. EXPECTING FOG TO DEVELOP AT THE USUAL LOCATIONS...CAUSING SOME VSBYS RESTRICTIONS. LIGHT OFFSHORE WINDS SHOULD DEVELOP...AND SHOULD KEEP MORE WIDESPREAD FOG ACROSS EASTERN MA AND RI. SHOULD THESE WINDS NOT DEVELOP AS EXPECTED... MORE WIDESPREAD FOG SHOULD DEVELOP. IFR TOWARD THE COAST...WITH VFR FARTHER INLAND. TOMORROW...CONDITIONS SLOWLY IMPROVE TO VFR ACROSS ALL AREAS. PATCHY DRIZZLE TO START THE DAY ACROSS EASTERN MA. MONDAY NIGHT...MAINLY MVFR TO VFR CONDITIONS. LOWER CONDITIONS MOST LIKELY TOWARD THE COAST WHERE THE BEST CHANCE FOR A RAIN SHOWER WILL EXIST. KBOS TAF...MODERATE CONFIDENCE...MAINLY DUE TO TIMING ISSUES. FOG COULD BE MORE WIDESPREAD IF OFFSHORE WIND DO NOT DEVELOP AS STRONGLY AS CURRENT EXPECTATIONS. LOWER VSBYS AND CIGS WOULD RESULT OTHERWISE. KBDL TAF...HIGH CONFIDENCE IN TRENDS. MODERATE CONFIDENCE IN TIMING. OUTLOOK...TUESDAY THROUGH THURSDAY...MODERATE CONFIDENCE TUESDAY...MAINLY MVFR TO VFR CONDITIONS OVER THIS TIME PERIOD. LOWER CONDITIONS MOST LIKELY ALONG THE COASTAL PLAIN WHERE THE BEST CHANCE FOR A PERIOD OF RAIN SHOWER WILL EXIST. WEDNESDAY AND THURSDAY...MAINLY VFR BUT A PERIOD OF MVFR CONDITIONS ARE POSSIBLE ESPECIALLY LATER THU OR THU NIGHT. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE. CONDITIONS WILL BE BELOW SCA...HOWEVER THERE MAY BE AN HOUR OR TWO WHERE SEAS INCREASE TO 5FT ACROSS THE SOUTHERN WATERS. BECAUSE OF THE LOW CONFIDENCE LEFT IT OUT FOR NOW. OTHERWISE WINDS WILL DECREASE THROUGH TONIGHT ALLOWING FOR SEAS TO RELAX. DRIZZLE AND FOG WILL BE THE MAIN CONCERN TONIGHT AND INTO MONDAY...WHICH COULD LOWER VISIBILITIES. OUTLOOK...TUESDAY THROUGH THURSDAY... TUESDAY...MODERATE TO HIGH CONFIDENCE. OCEAN STORM WILL PASS WELL EAST OF THE REGION. PRESSURE GRADIENT SHOULD STILL INCREASE ENOUGH FOR A PERIOD OF NORTHERLY SCA WIND GUSTS AND SCA SEAS ON TUESDAY. WEDNESDAY AND THURSDAY...MODERATE TO HIGH CONFIDENCE. SOME UPPER LEVEL RIDGING SHOULD KEEPS WINDS BELOW SCA THRESHOLDS. HOWEVER...SWELL WILL RESULT IN SCA SEAS AT TIMES ACROSS THE SOUTHERN AND EASTERN ATLANTIC WATERS. && .TIDES/COASTAL FLOODING... ASTRONOMICAL TIDES ARE QUITE HIGH TUESDAY MORNING...WITH AN 11.9 HIGH TIDE IN BOSTON. FORTUNATELY...IT LOOKS LIKE THE OCEAN STORM WILL INTENSIFY TOO FAR EAST AND TOO LATE FOR A SIGNIFICANT COASTAL FLOOD EVENT. HOWEVER...STILL THE POTENTIAL FOR SPLASH OVER AND POCKETS OF VERY MINOR COASTAL FLOODING ACROSS THE EASTERN MA COAST GIVEN THE HIGH ASTRONOMICAL TIDES. IN ADDITION...MINOR BEACH EROSION IS ALSO A POSSIBILITY DURING THE TUESDAY HIGH TIDE CYCLES ALONG THE OUTER CAPE OCEAN SIDE AND THE EAST SHORE OF NANTUCKET. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...BELK/FRANK NEAR TERM...BELK SHORT TERM...BELK LONG TERM...FRANK AVIATION...BELK/FRANK MARINE...BELK/FRANK TIDES/COASTAL FLOODING...STAFF
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
237 PM EST SUN DEC 1 2013 .DISCUSSION... CURRENT THROUGH MONDAY...MSAS AND RUC13 SURFACE ANALYSIS STILL SHOWING THAT A COASTAL TROUGH WAS SITUATED OFF THE VOLUSIA AND NORTH BREVARD COASTS...AND ON TOP OF THE GULF STREAM. RADAR TRENDS SHOW THAT THE SHOWERS EMBEDDED IN THE FLOW TO THE EAST OF THE TROUGH AXIS WERE NOT MAKING IT VERY FAR WEST OF THE TROUGH AXIS WHILE NORTHERLY WINDS ALONG THE COAST INTERACTING WITH EASTERLY WINDS JUST OFF THE SURFACE FROM CAPE CANAVERAL SOUTH WERE PRODUCING PERSISTENT LINES OF MODERATE TO OCCASIONALLY HEAVY RAIN FROM VERO BEACH SOUTH. STORM REPORTS INDICATED LOCALIZED AMOUNTS OF 3 TO 4 INCHES OR MORE IN THE VERO BEACH AREA SINCE DAYBREAK WITH MORE RAIN MOVING IN OFF THE OCEAN. VISIBLE SATELLITE IMAGES WERE SHOWING SEA FOG ALONG THE VOLUSIA COUNTY COAST AND NEARSHORE WATERS. A RECENT REPORT CALLED INTO THE OFFICE FROM PEOPLE ON THE INTRACOASTAL WATERWAY IN THE PONCE INLET AREA INDICATED VISIBILITIES DOWN TO LESS THAN HALF A MILE. THE COASTAL TROUGH WL BEGIN TO LIFT NORTHEAST AFTER MIDNIGHT. THIS WILL ALLOW THE WINDS TO SHIFT BACK TO THE NORTHWEST LATE OVERNIGHT AND REMAIN OUT OF THE NORTHWEST AND WEST MONDAY AS THE TROUGH DEEPENS INTO A LOW OFF THE GEORGIA SOUTH CAROLINA COAST. MODELS DEPICT A WEAK FRONTAL TROUGH/BOUNDARY ASSOCIATED WITH THE FORMING LOW MOVING DOWN THE PENINSULA MONDAY AND CLEARING EAST CENTRAL FLORIDA MONDAY NIGHT. GUIDANCE NOT SHOWING MUCH PRECIP WITH THE BOUNDARY OR A DRYING TREND WITH THE NORTHWEST FLOW BEHIND THE DEPARTING BOUNDARY. LOWS MONDAY MORNING EXPECTED TO BE IN THE MID AND UPPER 50S. THE NORTHWEST FLOW WILL KEEP MONDAYS HIGHS IN THE LOW AND MIDDLE 70S. THE RAIN CONFINED TO THE COAST AFTER MIDNIGHT AND OVER THE COASTAL WATERS MONDAY. A SECONDARY FRONTAL PSG TUE NIGHT SHOULD ONLY BRING INCRSD CLOUDS/SPRINKLES. WILL HOLD POPS BELOW 20 PERCENT. TEMPS WILL BEGIN A VERY SLOW/GRADUAL MODIFICATION TUE. WED-SAT...(PREVIOUS DISC) LARGE ANTICYCLONE EXPANDS FROM THE YUCATAN PENINSULA TO SOUTH FLORIDA TO NEAR BERMUDA DURING THIS PERIOD. MEANWHILE...A SURFACE HIGH OVER THE WESTERN ATLANTIC REMAINS NEARLY STATIONARY WITH ASSOCIATED RIDGE EXTENDING TO CENTRAL FLORIDA. RESULTANT PATTERN WILL FAVOR A LIGHT SE/S FLOW WITH NO LARGE SCALE WX IMPACTS. SOME PERIODS OF SHALLOW/ENHANCED MOISTURE MAY EVENTUALLY PROMPT A SMALL CHANCE OF MARINE/COASTAL SHOWERS...BUT PROSPECT TOO ILL-DEFINED AT THIS TIME TO INSERT MENTIONABLE POPS. MAX TEMPS WILL GRADUALLY CLIMB TO LOWER 80S WITH MINS LOWER/MID 60S BY THU...CONTINUING INTO THE WEEKEND. EXCEPTIONS WILL BE ALONG COAST NORTH OF THE CAPE WHERE ONSHORE FLOW ACROSS COLDER SHELF WATERS WILL MODIFY HIGHS TO UPPER 70S...AND COASTAL AREAS SOUTH OF VERO BEACH WHERE WARMER WATERS WILL MODIFY LOWS TO THE UPPER 60S/NEAR 70. && .AVIATION... CURRENT-OVERNIGHT...VFR CEILINGS AND VISIBILITIES SANFORD ORLANDO KISSIMMEE AND WEST. PREVAILING MVFR WITH TEMPO IFR AND LIFR CONDITIONS ALONG THE COAST KOMN-JUPITER INLET. SCT-BKN FL010 OR BELOW 06Z-14Z THEN VFR AFTER 15Z AS THE NORTHWEST WINDS CLEARS OUT THE AIR MASS NORTH TO SOUTH. && .MARINE... CURRENT THROUGH MONDAY...THE TROUGH OFF VOLUSIA AND NORTH BREVARD COAST WAS PRODUCING NORTHERLY WINDS OVER THE NEARSHORE...THE INTRACOASTAL WATERS...THE HALIFAX RIVER IN VOLUSIA AND THE INDIAN RIVER LAGOON FROM BREVARD TO MARTIN COUNTY. BUOYS AND SURFACE OBSERVATION ALONG THE COAST FROM SAINT AUGUSTINE TO JUPITER INLET BACK THIS UP BY RECORDING INDICATING NORTHERLY WINDS IN THE 10 TO 15 KNOT RANGE. SEAS HEIGHTS BEING REPORTED WERE 7 FEET OR LESS. WINDS START BACKING TO THE NORTHWEST OVERNIGHT AS THE COASTAL TROUGH BEGINS TO MOVE OFF TO THE NORTHEAST. THE SEA FOG ALONG THE VOLUSIA AND NORTH BREVARD COAST SHOULD DISSIPATE DURING THE EVENING. THE LOW CLOUDS AND RAIN ALONG THE COAST FROM SOUTH BREVARD TO JUPITER INLET WILL MOST LIKELY PERSIST AS LONG AS THE WIND STAYS NORTH AND NORTH NORTHWEST. ONCE THE WINDS STEADY UP OUT OF THE NORTHWEST THE PRECIP AT THE COAST AND JUST OFF THE BEACHES WILL END AND BECOME ISOLATED AWAY FROM THE COAST. TUE-THU...(PREV DISC) RATHER LIGHT/VARIABLE FLOW TUE THEN SE/S BELOW 15 KT THROUGH THU AS SURFACE HIGH BUILDS OFFSHORE AND RIDGE EXTENDS TO CENTRAL PENINSULA. SEAS WILL SUBSIDE TO NEAR 2 FEET CLOSE TO THE COAST AND 3-4 FEET WITHIN THE GULF STREAM TUE-THU AS RIDGE LIES OVERHEAD. && .PRELIMINARY POINT TEMPS/POPS... DAB 57 73 50 74 / 20 10 0 10 MCO 59 75 53 77 / 10 10 0 10 MLB 60 74 54 74 / 20 10 0 10 VRB 59 76 53 76 / 20 10 0 10 LEE 56 73 51 76 / 10 10 0 10 SFB 58 74 52 76 / 20 10 0 10 ORL 59 74 54 76 / 10 10 0 10 FPR 60 76 53 75 / 20 10 0 10 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EST THIS AFTERNOON FOR WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE-WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE. && $$ SHORT TERM...WIMMER LONG TERM....PENDERGRAST
AREA FORECAST DISCUSSION
NWS MIAMI FL
104 PM EST SUN DEC 1 2013 .AVIATION... SCATTERED SHOWERS WILL CONTINUE TO IMPACT THE EAST COAST TERMINALS THROUGH THE LATE AFTERNOON HOURS BEFORE DIMINISHING. THESE WILL BE CAPABLE OF PRODUCING SUB VFR CIGS/VSBYS PERIODICALLY...ESPECIALLY IN THE HEAVIER SHOWERS THAT MOVE THROUGH. ANOTHER ROUND OF FOG AROUND THE APF TERMINAL WILL REMAIN POSSIBLE LATE TONIGHT INTO MONDAY MORNING AHEAD OF AN APPROACHING FRONTAL BOUNDARY. LIGHT NORTHWEST WINDS WILL FOLLOW THIS BOUNDARY THROUGH THE DAY TOMORROW WITH MOSTLY DRY CONDITIONS EXPECTED. && .PREV DISCUSSION... /ISSUED 951 AM EST SUN DEC 1 2013/ UPDATE... THE SHERIFF OFFICES AND THE OBSERVATIONS OVER THE INTERIOR AND WEST COAST METRO AREAS OF SOUTH FLORIDA ARE NOW REPORTING VISIBILITIES TO BE BETWEEN 1 TO 3 MILES IN THE FOG. SO WILL LET THE DENSE FOG ADVISORY EXPIRED AT 10 AM EDT THIS MORNING FOR THE INTERIOR AND WEST COAST METRO AREAS. THE FOG SHOULD CONTINUE TO BURN OFF THROUGH NOON TIME ALLOWING FOR THE SKIES TO BECOME PARTLY CLOUDY BY THIS AFTERNOON ALONG WITH DRY WEATHER. SO WILL SHOW A TREND OF CLEARING SKIES ALONG WITH DRY CONDITIONS FOR THE INTERIOR AND WEST COAST METRO AREAS. FOR THE EAST COAST METRO AREAS...THERE HAS BEEN SOME ISOLATED SHOWERS WORKING INTO THIS AREA FROM THE ATLANTIC WATERS. THE ISOLATED SHOWERS WILL CONTINUE TO WORK INTO THE EAST COAST METRO AREAS THROUGH THE AFTERNOON HOURS ON THE EASTERLY WIND FLOW. SO WILL KEEP A SLIGHT CHANCE OF SHOWERS IN PLACE FOR THE EAST COAST METRO AREAS THROUGH THIS AFTERNOON. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES ARE PLANNED. UPDATE...54/BNB PREV DISCUSSION... /ISSUED 642 AM EST SUN DEC 1 2013/ AVIATION... REDUCED VSBYS IN FOG ARE MAINLY IMPACTING THE APF SITE THIS MORNING AND INLAND OF THE EAST COAST TERMINALS. THIS SHOULD BURN OFF BY OR BETWEEN 8-9AM WITH VFR CONDITIONS RETURNING. THE BEST CHANCE OF SHOWERS WILL BE ALONG THE EAST COAST TODAY...WHICH WILL BE CAPABLE OF PRODUCING PERIODS OF REDUCED CIGS/VSBYS THROUGH THE DAY. WINDS WILL REMAIN OUT OF THE NORTHEAST AND INCREASE TO AROUND 10 KT THROUGH THE LATE MORNING AND AFTERNOON HOURS. ALTHOUGH CONFIDENCE REMAINS TOO LOW...WINDS COULD SHIFT TO THE WNW AT APF DUE A GULF COAST SEA BREEZE THROUGH THE AFTERNOON PERIOD. WILL MONITOR THIS AND UPDATE IF NEEDED. PREV DISCUSSION... /ISSUED 319 AM EST SUN DEC 1 2013/ DISCUSSION... HIGH PRESSURE TO THE NORTH CONTINUES TO BRING NORTHEASTERLY FLOW TO SOUTH FLORIDA. HOWEVER, THE HIGH WILL BEGIN TO WEAKEN TODAY, ALLOWING THE WINDS TO BECOME LIGHTER. THERE IS STILL A FEW SHOWERS OVER THE ATLANTIC WATERS. CURRENTLY, THEY ARE NOT IMPACTING THE CWA, BUT STILL HAVE A SLIGHT CHANCE IN THE FORECAST. THE HRRR DOES SHOW SOME ISOLATED SHOWERS OVER THE ATLANTIC COAST METRO AREAS THIS AFTERNOON, SO BROUGHT SLIGHT CHANCE POPS SOMEWHAT MORE WEST. MODELS STILL SHOWING A VERY WEAK FRONT PUSHING SOUTH THROUGH SOUTH FLORIDA TOMORROW, BUT LOOKS BARELY DISCERNIBLE IN THE MODELS. GFS HAS HIGH PRESSURE BUILDING OVER THE FLORIDA PENINSULA BY 00Z TUESDAY WITH NO PRECIPITATION AT ALL. THE ECMWF IS SIMILAR, BUT ABOUT 6 HOURS SLOWER WITH MORE BROAD WEAK HIGH PRESSURE BUILDING. EITHER WAY. THE BEST EVIDENCE OF THIS FRONT WILL LIKELY BE A WEAK WINDS SHIFT TOMORROW. BUT, LEFT A SLIGHT CHANCE OF SHOWERS ACROSS THE CWA FOR THE AFTERNOON HOURS. BUT, GIVEN CURRENT MODEL RUNS, COULD DEFINITELY SEE THIS BEING PULLED OUT OF THE FORECAST LATER TODAY. AFTER TOMORROW, IT IS HIGH PRESSURE FOR THE REMAINDER OF THE FORECAST PERIOD. THE AIR MASS WILL WARM VERY SLIGHTLY THROUGH THE WEEK, WITH PERHAPS A FEW LIGHT COASTAL SHOWERS POSSIBLE, ESPECIALLY IN THE OVERNIGHT HOURS. AVIATION... MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE EARLY MORNING HOURS. HOWEVER...AN AREA OF CLOUDINESS AND EMBEDDED SHOWERS IS MOVING WESTWARD INTO THE LOCAL ATLANTIC WATERS AND A FEW SHOWERS COULD IMPACT THE EAST COAST TERMINALS FROM TIME TO TIME. ONLY PASSING SHOWERS EXPECTED BUT WILL AMEND IF ANY VIS/CEILING RESTRICTIONS OCCUR BUT NOT EXPECTED. WINDS ACROSS THE EAST COAST TERMINALS STARTING TO BECOME LIGHT AND VARIABLE WITH AN OFF SHORE DRAINAGE FLOW BEGINNING. MARINE... HIGH PRESSURE TO THE NORTH WILL WEAKEN TODAY, BUT STILL KEEP EASTERLY FLOW OVER THE COASTAL WATERS. THE WEAKER WINDS WILL RESULT IN SEAS CONTINUING TO SUBSIDE TODAY. GIVEN THIS ALL ADVISORIES AND CAUTION STATEMENTS HAVE BEEN CANCELLED. THERE IS A SLIGHT CHANCE OF SHOWERS OVER THE NEXT COUPLE OF DAYS AS A VERY WEAK COLD FRONT SLIDES ACROSS THE AREA TOMORROW. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 62 78 58 79 / 10 - - - FORT LAUDERDALE 63 78 62 79 / 10 - - - MIAMI 64 80 62 79 / 10 - - - NAPLES 60 75 59 78 / - - - - && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...54/BNB AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
214 PM EST SUN DEC 1 2013 .SHORT TERM /TONIGHT THROUGH TUESDAY/... LATEST SURFACE ANALYSIS OVER THE SOUTHEAST UNITED STATES SHOWS WEAK HIGH PRESSURE CONTINUING TO BE THE DOMINATING INFLUENCE OF THE LOCAL WX. EAST AND SOUTHEAST FLOW ON SOUTHERN PERIPHERY OF THIS HIGH EARLIER ALLOWED FOR LOW LEVEL MOISTURE TO ADVECT IN A RESULT IN WIDESPREAD LOW CLOUDS. SINCE THEN...DEVELOPING SOUTHWEST FLOW DUE TO A SHIFT IN THE HIGH POSITION HAS ALLOWED FOR THE EROSION OF MOST OF THE LOW CLOUDS BUT HAS QUICKLY BEEN REPLACED BY A THIN VEIL OF CIRRUS. TEMPS LOOKS TO BE LARGELY UNAFFECTED BY THIS AS WE ARE ALREADY WITHING THREE DEGREES OF FORECAST HIGH OF ATLANTA CURRENTLY. FOR TONIGHT...THE FIRST IN A SERIES OF EMBEDDED SHORTWAVES WILL MOVE THROUGH ZONAL FLOW TO PRODUCE AN AREA OF MAINLY LIGHT RAIN OVER ALABAMA. MODELS HAVE BEEN BACKING OFF ON HOW MUCH THIS ENERGY TRANSLATES INTO ACTUAL PRECIP OVER OUR AREA AND INDEED FEEL AMOUNTS WILL BE ON THE LOW SIDE EVEN OVER WESTERN PORTIONS. THAT SAID...BASED ON WRF AND HRRR RUNS...IT SHOULD STILL RAIN EVEN IF ITS LIGHT AND HAVE UPPED CHANCES ALONG THE WEST CENTRAL BORDER THROUGH 15Z MONDAY. WILL LET EVENING AND MID SHIFT TAKE ANOTHER LOOK AS MAY STILL BE TOO LOW...GOING JUST BELOW LIKELY AT THIS POINT. WAVE CLEARS DURING THE AFTERNOON BUT ANOTHER WILL BE RIGHT ON ITS HEELS INTO MONDAY NIGHT. THIS ONE WILL BE MOVING MORE SOUTHWEST TO NORTHEAST TO AFFECT MAINLY THE NORTHERN TIER WITH MID RANGE CHANCE POPS. IN ADDITION TO LIGHT RAIN...COULD SEE SOME PATCHY FOG DEVELOPMENT WITH THIS SYSTEM OVER THE MOUNTAINS AND ALONG OUR WESTERN BORDER WITH ALABAMA. INCREASING TEMPERATURES THROUGH THE SHORT TERM WITH MID 60S TO AROUND 70 EXPECTED BY TUESDAY AFTERNOON. THIS WOULD BE A RADICAL DEPARTURE FROM THE EXTREME COLD OF THIS PAST WEEK AND WOULD RESULT IN TEMPS SOME 10 DEGREES ABOVE CLIMO. DEESE .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... SOME CHANGES MADE TO THE EXTENDED BASED ON GUIDANCE WHICH IS COMING IN QUITE A BIT WARMER FOR LATER IN THE WEEK. AHEAD OF THE FRONT PROGGED TO STALL ACROSS THE TENNESSEE VALLEY WHICH WILL SLOWLY MAKE ITS WAY TO THE SOUTHERN APPALACHIANS BY FRIDAY. RIDGING IN THE GULF REMAINS PRETTY STRONG BUT ALSO STRONGER LOW- LEVEL WAA. INCREASED TEMPS QUITE A BIT AND ACTUALLY HAVE NEAR- RECORD TO RECORD WARM MIN TEMPS FOR FRIDAY MORNING. POPS STILL LOOKING GOOD BUT WILL PROBABLY HAVE TO INCREASE THEM AS WE PROGRESS THROUGH THE WEEK. THERE IS SOME CONCERN ABOUT HAZARDOUS WEATHER AS GFS CAPES ARE ON THE INCREASE ESPECIALLY FOR FRIDAY AFTERNOON AND SOME QPF VALUES ARE PRETTY HEFTY...BUT WILL NARROW THAT DOWN AS WE GET CLOSER. A LOT OF UNCERTAINTY ON TIMING OF FROPA AND SUBSEQUENT CAD ONSET... ECMWF A LITTLE FASTER THAN THE GFS ON FROPA BUT BOTH HAVE SIMILAR TIMING WITH CAD ONSET....SO MADE NO CHANGES TO SATURDAY /AS THE SIGNIFICANT COOL-DOWN STARTS/ AND BEYOND BECAUSE OF THAT UNCERTAINTY. WILL BE INTERESTING TO SEE WHAT SENSIBLE WEATHER IMPACTS OCCUR WITH THE DIABATICALLY-ENHANCED CAD EVENT FOR EARLY NEXT WEEK. SEE PREVIOUS DISCUSSION BELOW. TDP LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... /ISSUED AT 342 AM EST SUN DEC 1 2013/ ONLY SMALL CHANCES FOR LIGHT RAIN MONDAY NIGHT AND TUESDAY DUE TO THE POTENTIAL OF A WEAK SHORT WAVE PASSING AND INCREASING ALTHOUGH WEAK SOUTHERLY LOW LEVEL FLOW. THIS WILL ALSO ALLOW THE AIRMASS TO WARM DURING THIS PERIOD. THE GFS AND EUROPEAN ARE IN BETTER AGREEMENT FOR THE EXTENDED PERIOD. SMALL CHANCES FOR LIGHT SHOWERS CONTINUE WEDNESDAY FROM SOUTHERLY LOW LEVEL FLOW AHEAD OF THE NEXT FRONT. GFS FASTER MOVING THE FRONT TO FAR NW GA LATE WEDNESDAY AND THE EUROPEAN MOVING THE FRONT TO THE OH AND LOWER MS VALLEYS. EITHER WAY DYNAMICS ARE WEAK. MOIST SW FLOW ALOFT INCREASES THURSDAY AND CONTINUES INTO SATURDAY AS THE COLD FRONT SHARPENS OVER THE TN VALLEY/SRN APPALACHIANS THURSDAY AND MOVES TO CENTRAL GA LATE FRIDAY AND TO SE GA/N FL ON SATURDAY. OVERALL THIS WILL MEAN A WETTER PERIOD... MOST SO FOR N GA...ALONG WITH WARMER OVERALL TEMPERATURES UNTIL THE FRONT PASSES BY. A COLD AIR DAMMING EVENT LOOKS TO SET UP FOR SUNDAY. BDL && AVIATION... 18Z UPDATE... WINDS HAVE BEEN VERY SLOW TO SHIFT OVER TODAY BUT FINALLY STARTING TO SEE SOME WESTERLY COMPONENT SHOW UP IN THE OBSERVATIONS AND WILL CARRY AS PREVAILING AT ONSET OF THIS TAF SET. SOUTHEAST CORNER OF FORECAST AREA INCLUDING MCN THE ONLY ONE HOLDING ONTO MVFR CIGS BUT DIFFICULT TO DETERMINE EXTENT GIVEN MASKING CIRRUS. FOR THE FORECAST...EXPECT MVFR TO REEMERGE MON MORNING BUT PERHAPS A FEW HOURS EARLIER THAN PREVIOUS FORECAST. NOW LOOKING AT AROUND 15Z AT ATL FOR MVFR AND -RA TO DEVELOP. ANOTHER SYSTEM WILL MOVE ACROSS MONDAY NIGHT AND MAY BRING ANOTHER CHANCE OF -RA BUT JUST OUTSIDE THIS TAF PERIOD. //ATL CONFIDENCE...18Z UPDATE... MEDIUM ON RA CHANCES AND MVFR TIMING. HIGH ON REMAINING ELEMENTS. DEESE && .PRELIMINARY POINT TEMPS/POPS... ATHENS 41 60 48 65 / 10 20 30 30 ATLANTA 46 59 49 66 / 20 50 30 30 BLAIRSVILLE 39 53 45 58 / 10 30 30 40 CARTERSVILLE 42 56 48 66 / 40 40 30 30 COLUMBUS 46 65 50 69 / 20 20 20 10 GAINESVILLE 43 55 48 62 / 10 20 30 30 MACON 41 66 44 69 / 10 20 20 10 ROME 41 56 48 65 / 40 50 30 30 PEACHTREE CITY 41 60 43 67 / 20 50 30 20 VIDALIA 48 66 48 71 / 5 10 20 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DEESE LONG TERM....TDP AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
144 PM CST SUN DEC 1 2013 .DISCUSSION... 302 AM CST TODAY... LOW PRESSURE IS SKIRTING EAST ACROSS THE CENTRAL GREAT LAKES WITH A TRAILING COLD FRONT SAGGING SOUTH ACROSS THE CENTRAL PART OF THE CWA EARLY THIS MORNING. A FEW RADAR RETURNS TO OUR NORTH MAINLY ASSOCIATED WITH MID LEVEL CLOUD COVER...AND PRECIP IS NOT MAKING ITS WAY TO THE SURFACE...NOR IS IT EXPECTED TO AS THE FRONT CONTINUES TO SLIP ACROSS THE CWA THROUGH THE MORNING. STRATUS DECK IS EVIDENT ON IR IMAGERY BUILDING SOUTH BEHIND THE FRONT. EXPECT THESE LOWER CLOUDS TO BUILD ACROSS THE FORECAST AREA LATER THIS MORNING THEN REMAIN IN PLACE THROUGH THE DAY AND TONIGHT. WEAK HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA TONIGHT...THOUGH MODEL RH FIELDS SHOW LITTLE IF ANY DISSIPATION OF THE STRATUS DECK. ASSUMING WE STAY CLOUDY OVERNIGHT...TEMPERATURES SHOULD STAY PROPPED UP INTO THE UPPER 20S TO LOW 30S DESPITE WINDS LIKELY GOING VERY LIGHT OR CALM. HOWEVER...IF WE DO SEE CLEARING...WILL HAVE TO MAKE HEFTY CHANGES TO OVERNIGHT LOWS WHICH COULD FALL 10+ DEGREES MORE THAN CURRENTLY FORECAST UNDER A STRONG RADIATIONAL COOLING SETUP. MONDAY... UPPER LOW DIGS FROM BRITISH COLUMBIA INTO THE PACIFIC NORTHWEST THIS PERIOD WHILE A LEAD WAVE KICKS EAST ACROSS THE NORTHERN PLAINS WITH SURFACE LOW UNDERGOING CYCLOGENESIS. ECMWF NO LONGER ADVERTISING SHORTWAVE EARLY MONDAY...WHICH IS IN LINE WITH OTHER MODEL SOLUTIONS THUS PULLED MENTION OF POPS MONDAY. BY MONDAY EVENING...H85 BAROCLINIC ZONE SETS UP FROM THE DAKOTAS INTO THE MID MISSISSIPPI VALLEY WITH A ZONE OF ISENTROPIC ASCENT FOCUSED JUST TO OUR WEST. STILL UNCERTAIN HOW FAR EAST THE PRECIP WILL EXTEND...BUT BEST CHANCES WILL BE IN THE NORTHWESTERN PORTIONS OF THE CWA AROUND ROCKFORD. PRECIP MAY START OFF AS RAIN SNOW MIX...BUT SHOULD TRANSITION TO ALL RAIN AS THE WARM AIR CONTINUES TO PUSH NORTHWARD. TEMPERATURES MAY RISE OVERNIGHT MONDAY NIGHT ACROSS PORTIONS IF NOT ALL OF THE CWA DEPENDING ON HOW QUICKLY THE WARM FRONT LIFTS ACROSS THE AREA. TUESDAY THROUGH WEDNESDAY... LONGWAVE TROUGH CONTINUES TO DEEPEN ACROSS THE WESTERN CONUS WITH DOWNSTREAM AMPLIFICATION OF THE RIDGE ACROSS THE CENTRAL CONUS. SURFACE LOW PROGGED TO TRACK FROM THE DAKOTAS INTO THE NORTHERN LAKES REGION THROUGH THE PERIOD WITH STRONG WARM ADVECTION AHEAD OF THE LOW WARMING H85 TEMPS TO AROUND 7-8C TUE/WED. 01/00Z EMCWF ACTUALLY THROWING A WRENCH INTO PREVIOUS FORECAST THINKING FOR THIS SYSTEM MIDWEEK...TRENDING MUCH FASTER AND MORE IN LINE WITH THE GFS. NOT QUITE READY TO BITE OFF ON THIS COMPLETELY AS OFTEN TIMES WITH CLOSED UPPER LOWS SLOWER MODEL SOLUTIONS TEND TO BE BETTER...AND WOULD NOT BE SURPRISED TO SEE THE GFS AND ECMWF TREND SLOWER IN THE NEXT COUPLE DAYS. TEMPERATURES ON WEDNESDAY A BIT TRICKY WITH BIG BUST POTENTIAL. SLIGHTLY FASTER OR SLOWER FROPA WILL RESULT IN A 15-20 DEGREE RANGE OF POSSIBLE TEMPERATURES. ECMWF CONTINUES TO BE AGGRESSIVE WITH TEMPERATURES AHEAD OF THE FRONT...SUGGESTING MID TO UPPER 50S ACROSS MUCH OF THE EASTERN HALF OF THE CWA EVEN WITH FASTER FROPA. THE GEM...WHICH IS SLOWER THAN THE GFS/ECMWF NOW SUGGESTING LOW TO MID 60S WEDNESDAY. TRENDED SLIGHTLY WARMER ACROSS THE EASTERN CWA WHICH WILL HAVE THE BEST LIKELIHOOD OF SEEING FULL WARMTH AHEAD OF THE FRONT. THURSDAY THROUGH SATURDAY... BY THURSDAY...H85 TEMPS SHOULD QUICKLY FALL TO AROUND -10C...THEN FURTHER COOL TO AROUND -15C TO -18C SATURDAY AS A COLD ARCTIC AIRMASS TRICKLES INTO THE REGION. BOTH THE GFS AND ECMWF INDICATE A SERIES OF WAVES LIFTING NORTHEAST ALONG THE FRONT CAUSING PRECIP NORTH OF THE FRONT AND POSSIBLY IMPACTING EASTERN PORTIONS OF THE CWA THURSDAY AND THURSDAY NIGHT. OTHERWISE...STRONG HIGH PRESSURE OVER THE NORTHERN PLAINS WILL BUILD SOUTHEAST WITH RIDGING IN PLACE FRIDAY INTO THE WEEKEND BRINGING MORE SETTLED AND COLD WEATHER...WITH HIGHS IN THE TEENS TO LOW 20S...AND SINGLE DIGIT LOWS FRIDAY AND SATURDAY. DEUBELBEISS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * MVFR CIGS WILL BE AROUND THROUGH AT LEAST MID AFTN. * MFR CIGS RETURN OVERNIGHT. JEE //DISCUSSION...UPDATED 18Z... MAJOR CONCERN IS MVFR CLOUDS FORMING OVER THE LAKE AND MOVING OVER NE IL. CLOUD DEVELOPMENT AND COVER REALLY BLOSSOMED AFTER 16Z SO ADJUSTED TAFS TO INCLUDE MVFR CIGS THROUGH MID AFTN. A MID LEVEL CLOUD DECK IS OV IOWA AND SLOWLY ADVANCING EAST. THINKING THE MVFR CLOUDS WILL DISSIPATE AS THE MID LEVEL DECK MOVES OVERHEAD. WINDS ALSO TURN MORE NORTHERLY AT THIS TIME WHICH WOULD REDUCE THE ADVECTION OF LAKE CLOUDS OVER LAND. THERE IS A CHANCE THAT THE MVFR CLOUDS MAY LINGER A BIT LONGER THAN CURRENTLY FCST THIS AFTN. LIGHT WINDS BCM LIGHT AND VARIABLE OVERNIGHT...WITH A NW COMPONENT AT ORD AND MDW AND EAST AT RFD. THE LIGHT FLOW AND LOW LEVEL MOISTURE SUGGEST MVFR CIGS REDEVELOP. GUIDANCE TRIES TO FORM FOG AS WELL...BUT THINKING CLOUD COVER WILL TRUMP FOG. VRB WINDS CONTINUE INTO THE AM WITH MVFR CIGS SCATTERING OUT. WINDS TURN SE ON THE BACKSIDE OF THE HIGH TOMORROW WITH SPEEDS ARND 10KT. THERE IS A SLIGHT CHANCE OF PRECIP IN THE LATE AFTN BUT GUIDANCE CONTINUES TO PULL FORCING AND MAJORITY OF PRECIP NORTH INTO WISCONSIN. THE PRECIP WOULD BE A WINTRY MIX OR ALL RAIN...BUT IT IS SO SLIGHT THAT IT WAS LEFT OUT OF THE TAFS FOR NOW. JEE //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN CIGS THROUGH 23Z. * MEDIUM-HIGH CONFIDENCE IN CIG FCST AFT 23Z. * HIGH CONFIDENCE IN ALL OTHER FCST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR PROBABLE. CHANCE OF -RASN. TUESDAY INTO WEDNESDAY...MVFR CIGS POSSIBLE. CHANCE OF RAIN ESPECIALLY WEDNESDAY. THURSDAY...SLGT CHANCE OF SHSN WITH MVFR VSBY. OTHERWISE MAINLY VFR. FRIDAY AND SATURDAY...MAINLY VFR. RATZER && .MARINE... 252 AM CST MAIN MARINE FORECAST CONCERNS FOCUS ON DEVELOPMENT OF STRONG LOW PRESSURE OVER THE PLAINS MONDAY-TUESDAY...WHICH THEN IS EXPECTED TO LIFT NORTHEAST ACROSS THE NORTHERN LAKES ON WEDNESDAY. THERE CONTINUES TO BE SOME SPREAD IN MODEL SOLUTIONS WITH THE DEPTH... TRACK AND TIMING OF THE LOW. WEAK LOW PRESSURE WAS OVER LOWER MICHIGAN STATE EARLY THIS MORNING...WITH A COLD FRONT TRAILING ACROSS SOUTHERN LAKE MICHIGAN. THE LOW WILL CONTINUE TO TRACK EAST ACROSS THE EASTERN LAKES THROUGH THIS EVENING...WITH THE FRONT PUSHING SOUTHEAST OF LAKE MICHIGAN LATER THIS MORNING. WEAK HIGH PRESSURE RIDGING WILL THEN MOVE ACROSS THE WESTERN LAKES LATER TODAY/TONIGHT...DRIFTING SLOWLY OFF TO THE EAST ON MONDAY. WITH A RELATIVELY WEAK PUSH TO THE FRONT TODAY... WINDS WILL SHIFT TO THE NORTH AT GENERALLY LESS THAN 15 KT. FORECAST MODELS CONTINUE TO DEPICT AN AREA OF LOW PRESSURE DEVELOPING ACROSS THE HIGH PLAINS BY EARLY MONDAY...WHICH THEN DEEPENS ACROSS THE CENTRAL PLAINS MONDAY NIGHT. VARIOUS MODEL SOLUTIONS CONTINUE TO SHOW DIFFERENCES WITH THE EVOLUTION OF THIS LOW THROUGH MID-WEEK...THOUGH THERE IS SOME CONSENSUS IN LIFTING THE LOW NORTHEAST ACROSS THE NORTHERN GREAT LAKES WEDNESDAY. GENERALLY HAVE CONTINUED TO FOLLOW THE SLOWER SOLUTIONS OF THE ECMWF/GEM/UKMET WITH THIS SYSTEM...THOUGH WILL HAVE TO SEE SOME OF THE DIFFERENCES IRONED OUT BEFORE CONFIDENCE INCREASES IN DETAILS OF STRENGTH/TRACK AND TIMING. IT DOES APPEAR THAT THE POTENTIAL EXISTS FOR SOUTHEAST 30-35 KT WINDS AHEAD OF THE LOW LATE TUESDAY INTO WEDNESDAY...AND WEST GALES LATER WEDNESDAY INTO THURSDAY WITH THE PASSAGE OF THIS STORM. STILL 3-4 DAYS OUT SO WILL NOT HAVE ANY HEADLINES...THOUGH WILL MENTION POSSIBLE GALES IN FORECAST FOR THIS PERIOD. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1201 PM CST Sun Dec 1 2013 .DISCUSSION... ISSUED 1027 AM CST Sun Dec 1 2013 Another weak cold front drifting southward over the FA this morning with north winds behind it, although light. Morning warm up very much ahead of diurnal curve yet again. Have adjusted the forecast temps up a degree or two, but warm up will be countered by weak cold air mixing in behind the boundary. Dryness of the column underestimated and cloud cover not materializing. Have adjusted the sky grids as well in the short term. Update out momentarily, to include a removal of the fog wording from this morning. && .AVIATION... ISSUED 1157 AM CST Sun Dec 1 2013 Similar issues to yesterdays forecast. VFR in the short term, light and variable winds. Trouble with late tonight and into tomorrow is the model mishandling of the RH in general. Going with more of a trend forecast, mid/high level clouds thin and allow some radiational cooling to set up another fog scenario. Starting at 3SM, but increasing dwpts at sfc and cooling in the overnight may result in a drop to IFR for the morning vis. Conservative for now, but will watch afternoon xovers as well. HJS && .PREV DISCUSSION... ISSUED 248 AM CST Sun Dec 1 2013 Main forecast challenge focuses on departing storm system for the middle and end of the week...and whether or not it will produce any wintry precipitation across central Illinois. SHORT TERM...Today through Tuesday Weak cold front currently across northern Illinois will sink southward today, eventually becoming stationary along the Ohio River by evening. Front will be accompanied by little in the way of sensible weather other than a shift in the wind. Low-level moisture seen on IR/fog satellite across southeast Missouri/far southern Illinois is progged by HRRR to remain mostly south of I-70 today, while patchy mid-level clouds over Iowa into far northern Illinois stay mostly north of the area. End result will be mostly sunny skies until later this afternoon when clouds begin to approach from the northwest. High temperatures will be bit cooler behind the cold front, ranging from the middle 40s far northwest around Galesburg to the lower 50s south of I-70. Boundary will remain in place along the Ohio River through Monday, before lifting back northward in response to rising upper-level heights Monday night into Tuesday. Models continue to show a subtle short-wave rippling eastward out of the Plains late Sunday night into Monday that could interact with the front to produce scattered light showers. Forecast soundings remain dry at low-levels: however, think forcing will be strong enough to mention a slight chance for showers on Monday. As front lifts northward, rain chances will shift into the southern Great Lakes on Tuesday. Brisk southerly winds south of the departing warm front will bring much warmer air into the region, with Tuesday afternoon highs reaching the lower to middle 50s. LONG TERM...Wednesday through Saturday Forecast becomes more challenging in the extended, as upper low currently over northwest British Columbia drops southward and carves a deep trough across the western CONUS by the middle of the week. Downstream ridging will place the Midwest/Great Lakes in a broad southwesterly flow pattern, leading to increased precip chances Wednesday into Thursday. Models have been struggling with the evolution of a surface low pressure system and its associated cold front for the past several runs: however, the 00z DEC 1 run seems to be coming into better agreement. While GFS remains a fast outlier, the latest ECMWF has sped up the front quite a bit. Following an ECMWF/GEM consensus yields FROPA across central Illinois on Wednesday followed by sharply colder conditions for the end of the week. Main question will be how much precip will hold back in the colder airmass Thursday and possibly Friday. Previous runs of the ECMWF had featured quite a bit of wintry precip Thursday night into Friday as a secondary wave of low pressure tracked along the departing front. While it still shows the potential for wintry precip, it has backed off/shifted E/SE with its latest solution. GEM seems to be the most consistent model over the past couple of days, so have trended toward its solution. With cold front passing on Wednesday, will mention a chance for showers. After FROPA, precip will largely shut off Wednesday night, before a wave of low pressure tracking from the lower Mississippi River Valley into the Ohio River Valley brings a renewed round of precip primarily across the eastern half of the KILX CWA on Thursday/Thursday night. Have focused highest POPs along/east of I-57 for both Thursday and Thursday night, tapering down to just slight chances further west along/west of the Illinois River. Precip type during the day Thursday will be rain across the east, with a rain/snow mix along I-55 and mostly light snow in the Illinois River Valley. As deeper layer of cold air arrives, precip will change to light snow across the board Thursday night, with a light accumulation possible. After that, will hold on to low chance POPs for snow across the far E/SE on Friday, although if trends continue, these may need to be dropped entirely. Main weather story for the end of the week will be the much colder conditions. Highs by Friday and Saturday will only be in the 20s, with overnight lows in the single digits and teens. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1153 AM CST SUN DEC 1 2013 .DISCUSSION... 302 AM CST TODAY... LOW PRESSURE IS SKIRTING EAST ACROSS THE CENTRAL GREAT LAKES WITH A TRAILING COLD FRONT SAGGING SOUTH ACROSS THE CENTRAL PART OF THE CWA EARLY THIS MORNING. A FEW RADAR RETURNS TO OUR NORTH MAINLY ASSOCIATED WITH MID LEVEL CLOUD COVER...AND PRECIP IS NOT MAKING ITS WAY TO THE SURFACE...NOR IS IT EXPECTED TO AS THE FRONT CONTINUES TO SLIP ACROSS THE CWA THROUGH THE MORNING. STRATUS DECK IS EVIDENT ON IR IMAGERY BUILDING SOUTH BEHIND THE FRONT. EXPECT THESE LOWER CLOUDS TO BUILD ACROSS THE FORECAST AREA LATER THIS MORNING THEN REMAIN IN PLACE THROUGH THE DAY AND TONIGHT. WEAK HIGH PRESSURE IS EXPECTED TO BUILD ACROSS THE AREA TONIGHT...THOUGH MODEL RH FIELDS SHOW LITTLE IF ANY DISSIPATION OF THE STRATUS DECK. ASSUMING WE STAY CLOUDY OVERNIGHT...TEMPERATURES SHOULD STAY PROPPED UP INTO THE UPPER 20S TO LOW 30S DESPITE WINDS LIKELY GOING VERY LIGHT OR CALM. HOWEVER...IF WE DO SEE CLEARING...WILL HAVE TO MAKE HEFTY CHANGES TO OVERNIGHT LOWS WHICH COULD FALL 10+ DEGREES MORE THAN CURRENTLY FORECAST UNDER A STRONG RADIATIONAL COOLING SETUP. MONDAY... UPPER LOW DIGS FROM BRITISH COLUMBIA INTO THE PACIFIC NORTHWEST THIS PERIOD WHILE A LEAD WAVE KICKS EAST ACROSS THE NORTHERN PLAINS WITH SURFACE LOW UNDERGOING CYCLOGENESIS. ECMWF NO LONGER ADVERTISING SHORTWAVE EARLY MONDAY...WHICH IS IN LINE WITH OTHER MODEL SOLUTIONS THUS PULLED MENTION OF POPS MONDAY. BY MONDAY EVENING...H85 BAROCLINIC ZONE SETS UP FROM THE DAKOTAS INTO THE MID MISSISSIPPI VALLEY WITH A ZONE OF ISENTROPIC ASCENT FOCUSED JUST TO OUR WEST. STILL UNCERTAIN HOW FAR EAST THE PRECIP WILL EXTEND...BUT BEST CHANCES WILL BE IN THE NORTHWESTERN PORTIONS OF THE CWA AROUND ROCKFORD. PRECIP MAY START OFF AS RAIN SNOW MIX...BUT SHOULD TRANSITION TO ALL RAIN AS THE WARM AIR CONTINUES TO PUSH NORTHWARD. TEMPERATURES MAY RISE OVERNIGHT MONDAY NIGHT ACROSS PORTIONS IF NOT ALL OF THE CWA DEPENDING ON HOW QUICKLY THE WARM FRONT LIFTS ACROSS THE AREA. TUESDAY THROUGH WEDNESDAY... LONGWAVE TROUGH CONTINUES TO DEEPEN ACROSS THE WESTERN CONUS WITH DOWNSTREAM AMPLIFICATION OF THE RIDGE ACROSS THE CENTRAL CONUS. SURFACE LOW PROGGED TO TRACK FROM THE DAKOTAS INTO THE NORTHERN LAKES REGION THROUGH THE PERIOD WITH STRONG WARM ADVECTION AHEAD OF THE LOW WARMING H85 TEMPS TO AROUND 7-8C TUE/WED. 01/00Z EMCWF ACTUALLY THROWING A WRENCH INTO PREVIOUS FORECAST THINKING FOR THIS SYSTEM MIDWEEK...TRENDING MUCH FASTER AND MORE IN LINE WITH THE GFS. NOT QUITE READY TO BITE OFF ON THIS COMPLETELY AS OFTEN TIMES WITH CLOSED UPPER LOWS SLOWER MODEL SOLUTIONS TEND TO BE BETTER...AND WOULD NOT BE SURPRISED TO SEE THE GFS AND ECMWF TREND SLOWER IN THE NEXT COUPLE DAYS. TEMPERATURES ON WEDNESDAY A BIT TRICKY WITH BIG BUST POTENTIAL. SLIGHTLY FASTER OR SLOWER FROPA WILL RESULT IN A 15-20 DEGREE RANGE OF POSSIBLE TEMPERATURES. ECMWF CONTINUES TO BE AGGRESSIVE WITH TEMPERATURES AHEAD OF THE FRONT...SUGGESTING MID TO UPPER 50S ACROSS MUCH OF THE EASTERN HALF OF THE CWA EVEN WITH FASTER FROPA. THE GEM...WHICH IS SLOWER THAN THE GFS/ECMWF NOW SUGGESTING LOW TO MID 60S WEDNESDAY. TRENDED SLIGHTLY WARMER ACROSS THE EASTERN CWA WHICH WILL HAVE THE BEST LIKELIHOOD OF SEEING FULL WARMTH AHEAD OF THE FRONT. THURSDAY THROUGH SATURDAY... BY THURSDAY...H85 TEMPS SHOULD QUICKLY FALL TO AROUND -10C...THEN FURTHER COOL TO AROUND -15C TO -18C SATURDAY AS A COLD ARCTIC AIRMASS TRICKLES INTO THE REGION. BOTH THE GFS AND ECMWF INDICATE A SERIES OF WAVES LIFTING NORTHEAST ALONG THE FRONT CAUSING PRECIP NORTH OF THE FRONT AND POSSIBLY IMPACTING EASTERN PORTIONS OF THE CWA THURSDAY AND THURSDAY NIGHT. OTHERWISE...STRONG HIGH PRESSURE OVER THE NORTHERN PLAINS WILL BUILD SOUTHEAST WITH RIDGING IN PLACE FRIDAY INTO THE WEEKEND BRINGING MORE SETTLED AND COLD WEATHER...WITH HIGHS IN THE TEENS TO LOW 20S...AND SINGLE DIGIT LOWS FRIDAY AND SATURDAY. DEUBELBEISS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * MVFR CIGS WILL BE AROUND THROUGH AT LEAST MID AFTN...PSBLY LONGER. * MFR CIGS RETURN OVERNIGHT. JEE //DISCUSSION...UPDATED 18Z... MAJOR CONCERN IS MVFR CLOUDS FORMING OVER THE LAKE AND MOVING OVER NE IL. CLOUD DEVELOPMENT AND COVER REALLY BLOSSOMED AFTER 16Z SO ADJUSTED TAFS TO INCLUDE MVFR CIGS THROUGH MID AFTN. A MID LEVEL CLOUD DECK IS OV IOWA AND SLOWLY ADVANCING EAST. THINKING THE MVFR CLOUDS WILL DISSIPATE AS THE MID LEVEL DECK MOVES OVERHEAD. WINDS ALSO TURN MORE NORTHERLY AT THIS TIME WHICH WOULD REDUCE THE ADVECTION OF LAKE CLOUDS OVER LAND. THERE IS A CHANCE THAT THE MVFR CLOUDS MAY LINGER A BIT LONGER THAN CURRENTLY FCST THIS AFTN. LIGHT WINDS BCM LIGHT AND VARIABLE OVERNIGHT...WITH A NW COMPONENT AT ORD AND MDW AND EAST AT RFD. THE LIGHT FLOW AND LOW LEVEL MOISTURE SUGGEST MVFR CIGS REDEVELOP. GUIDANCE TRIES TO FORM FOG AS WELL...BUT THINKING CLOUD COVER WILL TRUMP FOG. VRB WINDS CONTINUE INTO THE AM WITH MVFR CIGS SCATTERING OUT. WINDS TURN SE ON THE BACKSIDE OF THE HIGH TOMORROW WITH SPEEDS ARND 10KT. THERE IS A SLIGHT CHANCE OF PRECIP IN THE LATE AFTN BUT GUIDANCE CONTINUES TO PULL FORCING AND MAJORITY OF PRECIP NORTH INTO WISCONSIN. THE PRECIP WOULD BE A WINTRY MIX OR ALL RAIN...BUT IT IS SO SLIGHT THAT IT WAS LEFT OUT OF THE TAFS FOR NOW. JEE //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN CIGS THROUGH 22Z...MEDIUM CONFIDENCE IN MVFR CIGS SCATTERING OUT THIS AFTN. * HIGH CONFIDENCE IN ALL OTHER FCST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z... MONDAY NIGHT...MVFR PROBABLE. CHANCE OF -RASN. TUESDAY INTO WEDNESDAY...MVFR CIGS POSSIBLE. CHANCE OF RAIN ESPECIALLY WEDNESDAY. THURSDAY...SLGT CHANCE OF SHSN WITH MVFR VSBY. OTHERWISE MAINLY VFR. FRIDAY AND SATURDAY...MAINLY VFR. RATZER && .MARINE... 252 AM CST MAIN MARINE FORECAST CONCERNS FOCUS ON DEVELOPMENT OF STRONG LOW PRESSURE OVER THE PLAINS MONDAY-TUESDAY...WHICH THEN IS EXPECTED TO LIFT NORTHEAST ACROSS THE NORTHERN LAKES ON WEDNESDAY. THERE CONTINUES TO BE SOME SPREAD IN MODEL SOLUTIONS WITH THE DEPTH... TRACK AND TIMING OF THE LOW. WEAK LOW PRESSURE WAS OVER LOWER MICHIGAN STATE EARLY THIS MORNING...WITH A COLD FRONT TRAILING ACROSS SOUTHERN LAKE MICHIGAN. THE LOW WILL CONTINUE TO TRACK EAST ACROSS THE EASTERN LAKES THROUGH THIS EVENING...WITH THE FRONT PUSHING SOUTHEAST OF LAKE MICHIGAN LATER THIS MORNING. WEAK HIGH PRESSURE RIDGING WILL THEN MOVE ACROSS THE WESTERN LAKES LATER TODAY/TONIGHT...DRIFTING SLOWLY OFF TO THE EAST ON MONDAY. WITH A RELATIVELY WEAK PUSH TO THE FRONT TODAY... WINDS WILL SHIFT TO THE NORTH AT GENERALLY LESS THAN 15 KT. FORECAST MODELS CONTINUE TO DEPICT AN AREA OF LOW PRESSURE DEVELOPING ACROSS THE HIGH PLAINS BY EARLY MONDAY...WHICH THEN DEEPENS ACROSS THE CENTRAL PLAINS MONDAY NIGHT. VARIOUS MODEL SOLUTIONS CONTINUE TO SHOW DIFFERENCES WITH THE EVOLUTION OF THIS LOW THROUGH MID-WEEK...THOUGH THERE IS SOME CONSENSUS IN LIFTING THE LOW NORTHEAST ACROSS THE NORTHERN GREAT LAKES WEDNESDAY. GENERALLY HAVE CONTINUED TO FOLLOW THE SLOWER SOLUTIONS OF THE ECMWF/GEM/UKMET WITH THIS SYSTEM...THOUGH WILL HAVE TO SEE SOME OF THE DIFFERENCES IRONED OUT BEFORE CONFIDENCE INCREASES IN DETAILS OF STRENGTH/TRACK AND TIMING. IT DOES APPEAR THAT THE POTENTIAL EXISTS FOR SOUTHEAST 30-35 KT WINDS AHEAD OF THE LOW LATE TUESDAY INTO WEDNESDAY...AND WEST GALES LATER WEDNESDAY INTO THURSDAY WITH THE PASSAGE OF THIS STORM. STILL 3-4 DAYS OUT SO WILL NOT HAVE ANY HEADLINES...THOUGH WILL MENTION POSSIBLE GALES IN FORECAST FOR THIS PERIOD. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1038 AM CST Sun Dec 1 2013 .DISCUSSION... ISSUED 1027 AM CST Sun Dec 1 2013 Another weak cold front drifting southward over the FA this morning with north winds behind it, although light. Morning warm up very much ahead of diurnal curve yet again. Have adjusted the forecast temps up a degree or two, but warm up will be countered by weak cold air mixing in behind the boundary. Dryness of the column underestimated and cloud cover not materializing. Have adjusted the sky grids as well in the short term. Update out momentarily, to include a removal of the fog wording from this morning. HJS && .AVIATION... ISSUED 535 AM CST Sun Dec 1 2013 Will see a few hours of MVFR vsbys in fog early this morning, then VFR conditions are expected into this evening, before another threat for some lower vsbys in fog late tonight. A weak cold front was pushing across the forecast area early this morning with winds ahead of the front light southwesterly, and light northwest to north winds were reported behind the boundary. forecast soundings and time-height cross sections indicate other than some sct-bkn cirrus at times today, not much in the way of significant cloud cover expected until this evening when a weak weather system well out to our west spreads clouds into our area. Cig heights look to be from 8000-1000 feet AGL later this evening. Due to the very light wind regime and despite the expected cloud cover tonight, we do expect some light fog to develop after 06z over most of the area with short range ensembles suggesting areas around I-74 seeing the higher probabilities for lower vsbys due to the fog. For now, will bring vsbys down to 4-5sm in br late tonight. Smith && .PREV DISCUSSION... ISSUED 248 AM CST Sun Dec 1 2013 Main forecast challenge focuses on departing storm system for the middle and end of the week...and whether or not it will produce any wintry precipitation across central Illinois. SHORT TERM...Today through Tuesday Weak cold front currently across northern Illinois will sink southward today, eventually becoming stationary along the Ohio River by evening. Front will be accompanied by little in the way of sensible weather other than a shift in the wind. Low-level moisture seen on IR/fog satellite across southeast Missouri/far southern Illinois is progged by HRRR to remain mostly south of I-70 today, while patchy mid-level clouds over Iowa into far northern Illinois stay mostly north of the area. End result will be mostly sunny skies until later this afternoon when clouds begin to approach from the northwest. High temperatures will be bit cooler behind the cold front, ranging from the middle 40s far northwest around Galesburg to the lower 50s south of I-70. Boundary will remain in place along the Ohio River through Monday, before lifting back northward in response to rising upper-level heights Monday night into Tuesday. Models continue to show a subtle short-wave rippling eastward out of the Plains late Sunday night into Monday that could interact with the front to produce scattered light showers. Forecast soundings remain dry at low-levels: however, think forcing will be strong enough to mention a slight chance for showers on Monday. As front lifts northward, rain chances will shift into the southern Great Lakes on Tuesday. Brisk southerly winds south of the departing warm front will bring much warmer air into the region, with Tuesday afternoon highs reaching the lower to middle 50s. LONG TERM...Wednesday through Saturday Forecast becomes more challenging in the extended, as upper low currently over northwest British Columbia drops southward and carves a deep trough across the western CONUS by the middle of the week. Downstream ridging will place the Midwest/Great Lakes in a broad southwesterly flow pattern, leading to increased precip chances Wednesday into Thursday. Models have been struggling with the evolution of a surface low pressure system and its associated cold front for the past several runs: however, the 00z DEC 1 run seems to be coming into better agreement. While GFS remains a fast outlier, the latest ECMWF has sped up the front quite a bit. Following an ECMWF/GEM consensus yields FROPA across central Illinois on Wednesday followed by sharply colder conditions for the end of the week. Main question will be how much precip will hold back in the colder airmass Thursday and possibly Friday. Previous runs of the ECMWF had featured quite a bit of wintry precip Thursday night into Friday as a secondary wave of low pressure tracked along the departing front. While it still shows the potential for wintry precip, it has backed off/shifted E/SE with its latest solution. GEM seems to be the most consistent model over the past couple of days, so have trended toward its solution. With cold front passing on Wednesday, will mention a chance for showers. After FROPA, precip will largely shut off Wednesday night, before a wave of low pressure tracking from the lower Mississippi River Valley into the Ohio River Valley brings a renewed round of precip primarily across the eastern half of the KILX CWA on Thursday/Thursday night. Have focused highest POPs along/east of I-57 for both Thursday and Thursday night, tapering down to just slight chances further west along/west of the Illinois River. Precip type during the day Thursday will be rain across the east, with a rain/snow mix along I-55 and mostly light snow in the Illinois River Valley. As deeper layer of cold air arrives, precip will change to light snow across the board Thursday night, with a light accumulation possible. After that, will hold on to low chance POPs for snow across the far E/SE on Friday, although if trends continue, these may need to be dropped entirely. Main weather story for the end of the week will be the much colder conditions. Highs by Friday and Saturday will only be in the 20s, with overnight lows in the single digits and teens. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
244 PM EST SUN DEC 1 2013 .UPDATE... THE LONG TERM SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EST SUN DEC 1 2013 A WEAK COLD FRONT WILL MOVE INTO THE REGION FROM THE NORTH LATER TODAY...EVENTUALLY STALLING OUT NEAR THE OHIO RIVER EARLY MONDAY BEFORE RETURNING NORTH AS A WARM FRONT. CLOUDS WILL INCREASE TODAY AND TONIGHT...WITH A FEW RAIN SHOWERS DEVELOP ON MONDAY AS THE FRONT LIFTS BACK NORTH. STRONG LOW PRESSURE WILL TRACK INTO THE GREAT LAKES BY LATE WEDNESDAY...WITH A TRAILING COLD FRONT CROSSING THROUGH THE OHIO VALLEY INTO WEDNESDAY NIGHT AND THURSDAY AND BRINGING RAIN TO THE REGION. MUCH COLDER AIR WILL SPILL INTO CENTRAL INDIANA BEHIND THE FRONT...WITH THE POTENTIAL FOR PRECIPITATION TO END AS SNOW LATE WEEK. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1005 AM EST SUN DEC 1 2013 EXTENSIVE AREA OF STRATUS WAS ALONG AND SOUTH OF A VINCENNES TO GREENSBURG LINE WHILE MOSTLY CLEAR CONDITIONS WERE TO THE NORTH. HOWEVER AN AREA OF HIGH CLOUDS WAS SPREADING INTO OUR FAR NORTH. A WEAK AND DIFFUSE COLD FRONT WILL MOVE SOUTH ACROSS OUR REGION AND STALL OVER SOUTH CENTRAL SECTIONS BY THIS EVENING. THE MAIN CHANGES TO THIS FORECAST WILL BE TO REDUCE CLOUD COVER AS STRATUS TO OUR SOUTH HAS SHOWN NO PROGRESSION NORTHWARD AND RUC SOUNDINGS INDICATE THIS COULD BREAK UP LATER TODAY. EXPECT MOST AREAS NORTH AND CENTRAL TO START OUT MOSTLY SUNNY WITH PARTLY CLOUDY CONDITIONS ALL AREAS LATE TODAY. GIVEN THAT THERE WILL BE MORE SUNSHINE THAN PREVIOUSLY EXPECTED AND BASED ON RUC 2 METER TEMPERATURES...WILL RAISE HIGH TEMPERATURES TODAY ABOUT 3 DEGREES THAN WHAT PREVIOUSLY FORECASTED. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... ISSUED AT 329 AM EST SUN DEC 1 2013 FORECAST CHALLENGES FOCUS ON PRECIP CHANCES WITH THE BOUNDARY IN THE REGION LATE TONIGHT INTO EARLY TUESDAY. THE FRONT WILL BECOME NEARLY STATIONARY ACROSS THE REGION TONIGHT INTO EARLY MONDAY AS A BROADER WAVE ALOFT TRACKS OUT OF THE CENTRAL PLAINS AND INTO THE OHIO AND TENNESSEE VALLEYS BY MONDAY MORNING. MODEL SOUNDINGS INDICATING THE DEVELOPMENT OF A SHARP BUT SHALLOW INVERSION IN THE LOWEST 1-2KFT OVERNIGHT WITH THE LIKELIHOOD OF A LOW STRATUS DECK BECOMING WELL ESTABLISHED. HOWEVER WITH DRIER AIR PRESENT FURTHER UP THROUGH THE BOUNDARY LAYER...THINK THE MOIST LAYER WILL REMAIN TOO SHALLOW TO SUPPORT ANY PRECIP/DRIZZLE/SPRINKLES OVERNIGHT...AND HAVE REMOVED PRECIP CHANCES THROUGH DAYBREAK MONDAY. BEST CHANCE FOR A FEW RAIN SHOWERS LIKELY COMES MONDAY WITH SLIGHTLY BETTER FORCING ALOFT COURTESY OF THE AFOREMENTIONED UPPER WAVE AND PRESENCE OF DEEPER MOISTURE. LOWER LEVELS SHOULD WARM ENOUGH TO ALLOW PRECIP TO FALL AS ALL RAIN OVER FAR NORTHERN COUNTIES MONDAY MORNING. RAINFALL AMOUNTS WILL BE ONLY A FEW HUNDREDTHS AT BEST AND THE SPARSE NATURE OF THE RAIN SHOWERS WILL MEAN SOME LOCATIONS PROBABLY SEE NO PRECIP AT ALL. WILL MAINTAIN ONLY LOW CHANCE POPS INTO MONDAY EVENING. THE FRONT WILL LIFT NORTH OF THE REGION LATE MONDAY NIGHT IN RESPONSE TO LOW PRESSURE EJECTING OUT OF THE PACIFIC NORTHWEST AND INTO THE NORTHERN PLAINS BY TUESDAY MORNING. GUIDANCE CONTINUING TO VARY ON THE HANDLING OF THE SHARP POLAR VORTEX DIVING THROUGH THE NORTHERN ROCKIES AND THE OVERALL COMPLEX NATURE OF THE UPPER LEVEL FLOW. ONE TREND NOTED OVER THE LAST FEW MODEL RUNS HOWEVER IS A GENERAL CONSENSUS TOWARDS A FASTER EASTWARD PROGRESSION TO THE SURFACE WAVE AND ASSOCIATED COLD FRONT. THE OP GFS IS MOST PROGRESSIVE AND HAS SUPPORT FROM ITS ENSEMBLE MEMBERS...BUT APPEARS TO DAMPEN DOWNSTREAM UPPER RIDGING TOO QUICKLY. PREFER THE GROWING CONSENSUS PRESENTED BY THE OTHER MODELS WITH THE COLD FRONT QUICKLY APPROACHING THE MISSISSIPPI VALLEY BY WEDNESDAY MORNING. COULD SEE RAIN SHOWERS DEVELOP AS EARLY AS TUESDAY NIGHT AS A LOW LEVEL JET MOVES INTO THE OHIO VALLEY. TEMPS...UNDERCUT AGGRESSIVE MOS GUIDANCE OVERALL FOR MONDAY HIGHS WITH PRESENCE OF CLOUDS AND PRECIP LIKELY LIMITING WARMING. THE EXPANSION OF STRONG WARM ADVECTION SOUTH OF THE WARM FRONT ON TUESDAY SETTING THE STAGE FOR A MILD DAY EVEN DESPITE EXPECTED CLOUD COVER. MOS AGAIN LOOKED SOMEWHAT AGGRESSIVE...BUT A SEVERAL DEGREE BUMP IN TEMPS IS WARRANTED WITH THE ENTIRE AREA INTO THE MID/UPPER 50S. CLOSER TO THE WARMER MAVMOS TONIGHT WITH CLOUDS...THEN NEAR MOS FOR LOWS MONDAY/TUESDAY NIGHTS. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... ISSUED AT 244 PM EST SUN DEC 1 2013 PLENTY OF UNCERTAINTY ON HOW FAST COLD AIR WILL ARRIVE INTO THE AREA DURING THE EARLY PART OF THE LONG TERM. LATEST TREND HAS BEEN FOR A QUICKER ARRIVAL...ALTHOUGH A VERY QUICK LOOK AT THE 12Z ECMWF SHOWS THAT IT HAS DECIDED TO BE A LITTLE SLOWER ONCE AGAIN. SINCE PREVIOUS FORECAST WAS SO WARM DUE TO SLOWER TIMING...DECIDED TO GO A LITTLE COOLER THAN ALLBLEND EARLY IN THE EXTENDED. OTHERWISE GENERALLY STAYED WITH ALLBLEND. A COUPLE OF WAVES OF LOW PRESSURE WILL RIDE ALONG A FRONT TO OUR EAST DURING THE FIRST HALF OF THE LONG TERM. WITH THE EXPECTED THERMAL PROFILES...EXPECT A MIX OF RAIN AND SNOW THURSDAY WITH MAINLY SNOW ON FRIDAY. COULD BE SOME LOW ACCUMULATIONS OF SNOW. AS STATED EARLIER THOUGH...UNCERTAINTY IS HIGH SO FORECAST COULD CHANGE SIGNIFICANTLY DEPENDING ON SPEED OF COLD AIR AND WHERE FRONT ENDS UP. SECOND HALF OF LONG TERM LOOKS COLD AND DRY AS ARCTIC AIR SETTLES IN. && .AVIATION /DISCUSSION FOR THE 011800Z TAF ISSUANCE/... ISSUED AT 1150 AM EST SUN DEC 1 2013 VFR CONDITIONS THIS AFTERNOON WILL GIVE WAY TO MVFR OVERNIGHT. COLD FRONT IS MOVING INTO CENTRAL INDIANA NOW AND WILL SHIFT WINDS TO WEST THEN NORTHWEST THROUGH THE AFTERNOON. WIND SPEEDS WILL BE LESS THAN 10KT. LOOKS LIKE MAINLY MID CLOUD WILL BE ASSOCIATED WITH THE FRONT. UNCERTAINTY INCREASES FOR THE EVENING INTO THE OVERNIGHT PERIOD. FRONT WILL STALL OUT JUST SOUTH OF THE TAF SITES ALLOWING MOISTURE TO BEGIN TO POOL ALONG IT. THIS SHOULD EVENTUALLY CREATE SOME FOG AND MVFR CEILINGS. TIMING AND COVERAGE IS UNCERTAIN SO FOR NOW KEPT AROUND 08Z AS START TIME FOR LOWER CONDITIONS. LOWER CONDITIONS SHOULD PERSIST THROUGH MONDAY MORNING WITH FRONT REMAINING IN THE AREA. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...JH SHORT TERM...RYAN LONG TERM....50 AVIATION...50 VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1150 AM EST SUN DEC 1 2013 .UPDATE... THE AVIATION SECTION HAS BEEN UPDATED BELOW. && .SYNOPSIS... ISSUED AT 329 AM EST SUN DEC 1 2013 A WEAK COLD FRONT WILL MOVE INTO THE REGION FROM THE NORTH LATER TODAY...EVENTUALLY STALLING OUT NEAR THE OHIO RIVER EARLY MONDAY BEFORE RETURNING NORTH AS A WARM FRONT. CLOUDS WILL INCREASE TODAY AND TONIGHT...WITH A FEW RAIN SHOWERS DEVELOP ON MONDAY AS THE FRONT LIFTS BACK NORTH. STRONG LOW PRESSURE WILL TRACK INTO THE GREAT LAKES BY LATE WEDNESDAY...WITH A TRAILING COLD FRONT CROSSING THROUGH THE OHIO VALLEY INTO WEDNESDAY NIGHT AND THURSDAY AND BRINGING RAIN TO THE REGION. MUCH COLDER AIR WILL SPILL INTO CENTRAL INDIANA BEHIND THE FRONT...WITH THE POTENTIAL FOR PRECIPITATION TO END AS SNOW LATE WEEK. && .NEAR TERM /REST OF TODAY/... ISSUED AT 1005 AM EST SUN DEC 1 2013 EXTENSIVE AREA OF STRATUS WAS ALONG AND SOUTH OF A VINCENNES TO GREENSBURG LINE WHILE MOSTLY CLEAR CONDITIONS WERE TO THE NORTH. HOWEVER AN AREA OF HIGH CLOUDS WAS SPREADING INTO OUR FAR NORTH. A WEAK AND DIFFUSE COLD FRONT WILL MOVE SOUTH ACROSS OUR REGION AND STALL OVER SOUTH CENTRAL SECTIONS BY THIS EVENING. THE MAIN CHANGES TO THIS FORECAST WILL BE TO REDUCE CLOUD COVER AS STRATUS TO OUR SOUTH HAS SHOWN NO PROGRESSION NORTHWARD AND RUC SOUNDINGS INDICATE THIS COULD BREAK UP LATER TODAY. EXPECT MOST AREAS NORTH AND CENTRAL TO START OUT MOSTLY SUNNY WITH PARTLY CLOUDY CONDITIONS ALL AREAS LATE TODAY. GIVEN THAT THERE WILL BE MORE SUNSHINE THAN PREVIOUSLY EXPECTED AND BASED ON RUC 2 METER TEMPERATURES...WILL RAISE HIGH TEMPERATURES TODAY ABOUT 3 DEGREES THAN WHAT PREVIOUSLY FORECASTED. && .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... ISSUED AT 329 AM EST SUN DEC 1 2013 FORECAST CHALLENGES FOCUS ON PRECIP CHANCES WITH THE BOUNDARY IN THE REGION LATE TONIGHT INTO EARLY TUESDAY. THE FRONT WILL BECOME NEARLY STATIONARY ACROSS THE REGION TONIGHT INTO EARLY MONDAY AS A BROADER WAVE ALOFT TRACKS OUT OF THE CENTRAL PLAINS AND INTO THE OHIO AND TENNESSEE VALLEYS BY MONDAY MORNING. MODEL SOUNDINGS INDICATING THE DEVELOPMENT OF A SHARP BUT SHALLOW INVERSION IN THE LOWEST 1-2KFT OVERNIGHT WITH THE LIKELIHOOD OF A LOW STRATUS DECK BECOMING WELL ESTABLISHED. HOWEVER WITH DRIER AIR PRESENT FURTHER UP THROUGH THE BOUNDARY LAYER...THINK THE MOIST LAYER WILL REMAIN TOO SHALLOW TO SUPPORT ANY PRECIP/DRIZZLE/SPRINKLES OVERNIGHT...AND HAVE REMOVED PRECIP CHANCES THROUGH DAYBREAK MONDAY. BEST CHANCE FOR A FEW RAIN SHOWERS LIKELY COMES MONDAY WITH SLIGHTLY BETTER FORCING ALOFT COURTESY OF THE AFOREMENTIONED UPPER WAVE AND PRESENCE OF DEEPER MOISTURE. LOWER LEVELS SHOULD WARM ENOUGH TO ALLOW PRECIP TO FALL AS ALL RAIN OVER FAR NORTHERN COUNTIES MONDAY MORNING. RAINFALL AMOUNTS WILL BE ONLY A FEW HUNDREDTHS AT BEST AND THE SPARSE NATURE OF THE RAIN SHOWERS WILL MEAN SOME LOCATIONS PROBABLY SEE NO PRECIP AT ALL. WILL MAINTAIN ONLY LOW CHANCE POPS INTO MONDAY EVENING. THE FRONT WILL LIFT NORTH OF THE REGION LATE MONDAY NIGHT IN RESPONSE TO LOW PRESSURE EJECTING OUT OF THE PACIFIC NORTHWEST AND INTO THE NORTHERN PLAINS BY TUESDAY MORNING. GUIDANCE CONTINUING TO VARY ON THE HANDLING OF THE SHARP POLAR VORTEX DIVING THROUGH THE NORTHERN ROCKIES AND THE OVERALL COMPLEX NATURE OF THE UPPER LEVEL FLOW. ONE TREND NOTED OVER THE LAST FEW MODEL RUNS HOWEVER IS A GENERAL CONSENSUS TOWARDS A FASTER EASTWARD PROGRESSION TO THE SURFACE WAVE AND ASSOCIATED COLD FRONT. THE OP GFS IS MOST PROGRESSIVE AND HAS SUPPORT FROM ITS ENSEMBLE MEMBERS...BUT APPEARS TO DAMPEN DOWNSTREAM UPPER RIDGING TOO QUICKLY. PREFER THE GROWING CONSENSUS PRESENTED BY THE OTHER MODELS WITH THE COLD FRONT QUICKLY APPROACHING THE MISSISSIPPI VALLEY BY WEDNESDAY MORNING. COULD SEE RAIN SHOWERS DEVELOP AS EARLY AS TUESDAY NIGHT AS A LOW LEVEL JET MOVES INTO THE OHIO VALLEY. TEMPS...UNDERCUT AGGRESSIVE MOS GUIDANCE OVERALL FOR MONDAY HIGHS WITH PRESENCE OF CLOUDS AND PRECIP LIKELY LIMITING WARMING. THE EXPANSION OF STRONG WARM ADVECTION SOUTH OF THE WARM FRONT ON TUESDAY SETTING THE STAGE FOR A MILD DAY EVEN DESPITE EXPECTED CLOUD COVER. MOS AGAIN LOOKED SOMEWHAT AGGRESSIVE...BUT A SEVERAL DEGREE BUMP IN TEMPS IS WARRANTED WITH THE ENTIRE AREA INTO THE MID/UPPER 50S. CLOSER TO THE WARMER MAVMOS TONIGHT WITH CLOUDS...THEN NEAR MOS FOR LOWS MONDAY/TUESDAY NIGHTS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... ISSUED AT 329 AM EST SUN DEC 1 2013 ENSEMBLES ARE IN GOOD AGREEMENT ON THE EVOLVING WEATHER PATTERN LATER THIS WEEK. MEAN UPPER TROUGHING EXPECTED FROM THE NORTHERN PLAINS BACK INTO THE SOUTHWEST...WHILE UPPER RIDGING DEVELOPS OVER THE SOUTHEAST. THIS WILL RESULT IN SOUTHWESTERLY UPPER FLOW LOCALLY. APPEARS A DECENT CHUNK OF ENERGY WILL EJECT OUT OF THE WESTERN TROUGH INTO WESTERN GREAT LAKES AROUND WEDNESDAY. WILL KEEP SOME RAIN CHANCES IN THE FORECAST FOR WEDNESDAY AS THE UPPER DISTURBANCE MOVES THROUGH. AFTER THAT...FORECAST BECOMES MORE MUDDLED AS THE POTENTIAL EXISTS FOR WAVES TO EJECT OUT OF THE WESTERN TROUGH. AT THIS POINT...THE ENSEMBLES DON/T INDICATE ANY MAJOR LOW PRESSURE SYSTEMS...BUT RATHER STABLE TYPE SURFACE WAVES RIPPLING ALONG A PRIMARY FRONTAL ZONE LOCATED OVER THE TENNESSEE VALLEY. ENSEMBLES SEEM TO KEY IN ON ONE WAVE MOVING THROUGH AROUND THURSDAY INTO EARLY FRIDAY...AND ANOTHER JUST AFTER THIS FORECAST PERIOD. ALTHOUGH AN ARGUMENT CAN BE MADE FOR AT LEAST SOME PRECIPITATION THREAT EVERY DAY...FOR NOW WILL KEEP THE POPS RESTRICTED TO THURSDAY AND FRIDAY. APPEARS THERE IS POTENTIAL FOR SOME LIGHT SNOW ACCUMULATIONS THURSDAY NIGHT INTO FRIDAY MORNING. && .AVIATION /DISCUSSION FOR THE 011800Z TAF ISSUANCE/... ISSUED AT 1150 AM EST SUN DEC 1 2013 VFR CONDITIONS THIS AFTERNOON WILL GIVE WAY TO MVFR OVERNIGHT. COLD FRONT IS MOVING INTO CENTRAL INDIANA NOW AND WILL SHIFT WINDS TO WEST THEN NORTHWEST THROUGH THE AFTERNOON. WIND SPEEDS WILL BE LESS THAN 10KT. LOOKS LIKE MAINLY MID CLOUD WILL BE ASSOCIATED WITH THE FRONT. UNCERTAINTY INCREASES FOR THE EVENING INTO THE OVERNIGHT PERIOD. FRONT WILL STALL OUT JUST SOUTH OF THE TAF SITES ALLOWING MOISTURE TO BEGIN TO POOL ALONG IT. THIS SHOULD EVENTUALLY CREATE SOME FOG AND MVFR CEILINGS. TIMING AND COVERAGE IS UNCERTAIN SO FOR NOW KEPT AROUND 08Z AS START TIME FOR LOWER CONDITIONS. LOWER CONDITIONS SHOULD PERSIST THROUGH MONDAY MORNING WITH FRONT REMAINING IN THE AREA. && .IND WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS...RYAN NEAR TERM...JH SHORT TERM...RYAN LONG TERM....JAS AVIATION...50 VISIT US AT HTTP://WWW.WEATHER.GOV/IND FOLLOW US ON TWITTER AND YOUTUBE AT: WWW.TWITTER.COM/NWSINDIANAPOLIS WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS JACKSON KY
351 PM EST SUN DEC 1 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 338 PM EST SUN DEC 1 2013 A BAND OF LOW CLOUDS REMAINS ACROSS THE REGION IN ADVANCE OF A WEAK COLD FRONT THAT IS BEGINNING TO SLOW DOWN AND STALL OUT. SOME OF THESE HAVE ERODED A BIT FROM THE SOUTH OR SOUTHEAST AND NORTHWEST THROUGHOUT THE DAY. THIS HAS LED TO THE COLDEST TEMPERATURES ON AVERAGE BETWEEN THE HAL ROGERS PARKWAY AND KY HIGHWAY 80 CORRIDOR AND INTERSTATE 64 CORRIDOR. SOME OF THE DEEPER SHELTERED VALLEYS NEVER REALLY MIXED OUT AND TEMPERATURES THERE ARE IN THE LOW TO MID 40S ATTM. OTHERWISE TEMPS WERE NEAR 50 ACROSS MUCH OF THE SOUTHERN CWA AND HAD NEARED 50 NORTH OF THE INTERSTATE 64 CORRIDOR. A WEAK DISTURBANCE IS EXPECTED TO MAINLY PASS TO OUR SOUTH LATER TONIGHT INTO MONDAY MORNING WHILE A MORE NORTHERN SHORTWAVE WILL PASS TO THE NORTH OF EASTERN KY ON MONDAY AFTERNOON AND EVENING. THIS WILL LEAD TO A BRIEF DEVELOPMENT OF A SOUTHEASTERN TROUGH BY MONDAY. THIS TROUGH WILL MOVE ON OFF TO THE EAST WITH SOME WEAK RIDGING PASSING THROUGH OVER THE SOUTHEASTERN US AND TN VALLEY FOR MON NIGHT INTO TUE. AT THE END OF THE PERIOD...A TROUGH IS ANTICIPATED TO EXTEND FROM CENTRAL CANADA INTO THE NORTHERN PLAINS AND THEN SOUTHWEST INTO THE ROCKIES AND CALIFORNIA WITH MORE OR LESS ZONAL FLOW IN THE EASTERN CONUS. AS AT THE SFC...THE BOUNDARY TO OUR NORTHWEST SHOULD STALL NEAR THE OH RIVER TONIGHT AND INTO MONDAY BEFORE RETURNING NORTH AS A WARM FRONT LATER ON MONDAY INTO TUESDAY. MODELS INDICATE A GENERAL GRADUAL INCREASE IN MOISTURE BELOW THE CURRENT CLOUD LAYER TONIGHT...BUT MEAGER OMEGA AT BEST. UP UNTIL TODAY AT LEAST...MODELS SEEM TO HAVE BEEN TOO AGGRESSIVE INCREASING LOW LEVEL MOISTURE. HOWEVER...DEWPOINTS HAVE CREPT UP INTO THE MID TO UPPER 30S IN WESTERN AND CENTRAL KY AND MIDDLE AND WESTERN TN. THIS LEADS TO UNCERTAINTY AS TO WHETHER OR NOT THE STRATOCU DECK COULD LOWER LATER TONIGHT INTO EARLY ON MONDAY AND WHETHER OR NOT THERE COULD BE SOME PATCHY DRIZZLE AT THAT TIME. THE 12Z NAM AND 12Z GFS HAD SOME LIGHT SPOTTY QPF WITH THIS LATE TONIGHT OR MONDAY. THE 18Z HRRR ALSO HAD SOME LIGHT SPOTTY QPF LATER TONIGHT. THE 15Z SREF POPS ARE LOW AND HAVE TRENDED DOWN SINCE 24 HOURS AGO. OPTED TO GO WITH A 10 POP FOR PATCHY DRIZZLE IN ALL BUT THE FAR SOUTHEAST LATE TONIGHT AND INTO MONDAY MORNING AND THEN STAYED CLOSE TO THE PREVIOUS FORECAST FOR LATER ON MONDAY INTO MONDAY EVENING WITH A SLIGHT CHANCE IN THE FAR NORTH. THIS LED TO BETTER ISC CONSISTENCY. WITH LOW CLOUDS EXPECTED FOR MOST...IF NOT ALL OF THE NIGHT...MIN T TONIGHT WILL BE CONSIDERABLY MILDER IN DEEPER SHELTERED VALLEY LOCATIONS COMPARED TO RECENT NIGHTS. MIN T SHOULD REMAIN ABOVE FREEZING IN ALL LOCATIONS. SOME THINNING OF THE CLOUDS IS ANTICIPATED ON MON AFTERNOON AND TEMPS SHOULD GENERALLY REACH THE LOW TO MID 50S. MIN T ON MON NIGHT IS A BIT MORE UNCERTAIN...AS SOME OF THE GUIDANCE SUGGESTS THERE COULD BE WINDOW OF TIME WHERE CLOUDS COULD BE THIN ENOUGH OR POSSIBLY BRIEFLY CLEAR AND ALLOW A RIDGE/VALLEY TEMP SPLIT TO DEVELOP IN SOUTHEASTERN VALLEYS. NEVERTHELESS...MIN T ON MON NIGHT SHOULD ALSO BE ABOVE NORMAL. OTHERWISE...THE BULK OF THE PERIOD SHOULD BE DRY WITH SOUTHERLY TO SOUTHWESTERLY LOW LEVEL FLOW INCREASING LATE IN THE PERIOD IN ADVANCE OF A DEVELOPING MUCH MORE SIGNIFICANT SYSTEM THAT WILL IMPACT THE REGION FROM MIDWEEK ON. THE 12Z AND 18Z NAM AS WELL AS THE 12Z ECMWF SUGGEST A STRAY SHOWER MIGHT BE POSSIBLE OVER THE SOUTHWEST ON TUE IN THE WARM SECTOR...BUT THE OTHER GUIDANCE WAS MORE SUPPORTIVE OF JUST A CONSIDERABLE AMOUNT OF CLOUDS FROM TIME TO TIME. MUCH OF THE RECENT MAX T GUIDANCE SUGGESTS TUE WILL BE RATHER MILD...ABOVE NORMAL AND IF CLOUDS WERE TO THIN FOR A WHILE 60 DEGREES WOULD BE REACHABLE IN MANY LOCATIONS. TUE TEMPS WERE RAISED A COUPLE OF DEGREES ON AVERAGE. .LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY) ISSUED AT 318 PM EST SUN DEC 1 2013 THE UPPER AIR PATTERN OVER THE EASTERN THIRD OF THE CONUS WILL FEATURE A LARGE STORM SYSTEM TAKING SHAPE OVER THE NORTHERN PLAINS TO BEGIN THE PERIOD. BOTH THE GFS AND ECMWF MODELS HAVE VERY SIMILAR SOLUTIONS REGARDING THE STRENGTH AND EVOLUTION OF THIS SYSTEM. THIS SYSTEM IS PROGGED TO MOVE ACROSS THE UPPER GREAT LAKES REGION WEDNESDAY NIGHT AND THURSDAY. AS IT DOES SO...A SURFACE COLD FRONT WILL MOVE INTO THE AREA FROM THE NORTHWEST...AND EVENTUALLY STALL ACROSS THE OHIO AND UPPER TENNESSEE VALLEY REGIONS FROM THURSDAY NIGHT THROUGH SUNDAY. WEAK WAVES OF LOW PRESSURE MOVING ALONG THIS BOUNDARY...COUPLED WITH A STRONG FEED OF MOISTURE OFF THE GULF OF MEXICO...WILL COMBINE TO BRING A PROLONGED PERIOD OF PRECIPITATION TO EASTERN KENTUCKY. THE FIRST COUPLE OF DAYS OF THE PERIOD WILL FEATURE PERSISTENT SOUTHERLY FLOW OFF THE GULF...WITH HIGH TEMPERATURES IN THE LOWER 60S ON WEDNESDAY...AND IN THE MID TO UPPER 50S ON THURSDAY. THE WARM MOIST AIR OFF THE GULF WILL BRING AN INCREASE IN CLOUD COVER AS THE FRONT APPROACHES FROM THE WEST. THE FIRST PRECIPITATION IS EXPECTED TO MOVE INTO THE NORTHWEST PART OF THE AREA EARLY WEDNESDAY MORNING...AS WARM MOIST AIR BEGINS TO INTERACT WITH THE LEADING EDGE OF THE APPROACHING COLD FRONT. AS THE FRONT CONTINUES TO MOVE SLOWLY EASTWARD...PRECIPITATION WILL INCREASE IN COVERAGE. THE FIRST GOOD CHANCE OF RAIN SHOULD ARRIVE WEDNESDAY NIGHT...AS THE FRONT MOVES SOUTH OF THE OHIO RIVER. THE BEST CHANCE FOR PRECIPITATION WILL OCCUR FROM EARLY THURSDAY MORNING THROUGH EARLY SATURDAY MORNING...AS THE FRONT STALLS OVER THE REGION. PRECIPITATION CHANCES SHOULD REMAIN IN THE FORECAST THROUGH SATURDAY NIGHT...AS YET ANOTHER WEAK WAVE OF LOW PRESSURE MOVES ALONG THE SLUGGISH FRONTAL BOUNDARY. TEMPERATURES WILL REMAIN WARM ENOUGH TO KEEP PRECIPITATION IN THE FORM OF RAIN FROM WEDNESDAY THROUGH FRIDAY AFTERNOON. WITH THE FRONT STALLED OVER THE AREA...AND WITH A STEADY FEED OF MOISTURE OFF THE GULF OF MEXICO INTERACTING WITH THE FRONT...THERE WILL THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. ONCE THE FRONT MOVES THROUGH THE AREA...AND WINDS SHIFT TO THE NORTHWEST AND EVENTUALLY NORTH...SNOW MAY BEGIN TO MIX WITH THE RAIN...BEGINNING IN THE FAR NORTHWESTERN PORTION OF THE FORECAST AREA. THE LATEST TIME HEIGHT CROSS SECTIONS AND SOUNDINGS SUPPORT A MIX OF RAIN AND SNOW FRIDAY NIGHT THROUGH THE END OF THE DAY ON SATURDAY. IF THE LATEST MODEL DATA HOLDS TRUE...THERE COULD BE ENOUGH COLD AIR IN PLACE ACROSS THE AREA FROM EARLY SATURDAY NIGHT THROUGH EARLY SUNDAY AFTERNOON FOR PRECIPITATION TO CHANGE OVER TO ALL SNOW. IF THIS TURNS OUT TO BE THE CASE...WE COULD SEE SOME LIGHT SNOW ACCUMULATIONS SATURDAY NIGHT AND SUNDAY ACROSS EASTERN KENTUCKY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1229 PM EST SUN DEC 1 2013 RETURN FLOW BETWEEN HIGH PRESSURE TO OUR SOUTHEAST AND A WEAK BOUNDARY CURRENTLY WORKING INTO THE OH VALLEY WILL CONTINUE THROUGH THE PERIOD...AND MOISTURE WILL CONTINUE TO BE GRADUALLY TRANSPORTED NORTHEASTWARD INTO THE REGION. THIS WILL LEAD TO A CONSIDERABLE AMOUNT OF LOW LEVEL (3.5-5KFT AFL) CLOUDS THROUGH THE PERIOD. DUE TO DRIER AIR IN THE LOWEST LEVELS...THESE CLOUDS SHOULD NOT LOWER BELOW 2KFT AGL...DURING THE 5Z TO 15Z PERIOD PER MODEL FORECAST SOUNDING AND LAMP DATA. OTHERWISE...VFR CONDITIONS SHOULD PERSIST THROUGH THE PERIOD. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JP LONG TERM...AR AVIATION...JP
AREA FORECAST DISCUSSION
NWS GRAY ME
1155 AM EST SUN DEC 1 2013 .SYNOPSIS... WEAK LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA THROUGH TONIGHT. A SECOND WEAK LOW WILL TRACK NORTHEAST AND PASS JUST OFFSHORE TONIGHT AND EARLY MONDAY. THESE TWO SYSTEMS WILL PRODUCE SOME OCCASIONAL LIGHT SNOW INTO TONIGHT, WITH MIXING OR A CHANGEOVER TO LIGHT RAIN POSSIBLE NEAR THE COAST. WEAK TROUGHING ALONG THE COAST KEEPS PRECIPITATION NEARBY ON MONDAY. LOW PRESSURE TRAVELS UP THE ATLANTIC COASTLINE TUESDAY, SPREADING MORE PRECIPITATION OVER THE REGION THROUGH WEDNESDAY MORNING. RIDGING BUILDS IN BRIEFLY BEFORE A COLD FRONT CROSSES THE REGION THURSDAY. && .NEAR TERM /UNTIL 5 PM THIS AFTERNOON/... 1155 AM...ONLY MINOR ADJUSTMENTS FOR THIS ESTF UPDATE LARGELY TO REFLECT THE CURRENT MESONET AND SHORT TERM TRENDS. PREV DISC... 945 AM...THE COASTAL FRONT IS SETTING UP SHOP JUST OFFSHORE THEN EXTENDS INTO MY EASTERN ZONES AND TO THE WEST OF ROCKLAND. I LOWERED MAXIMUM TEMPERATURES A BIT IN MANY AREAS AS A RESULT. MODELS HAVE A WEAK LOW TRAVELING NORTHEAST ALONG THIS BOUNDARY LATE TODAY AND TONIGHT WITH HEAVIEST QPF FOR MID COAST REGION. WHILE AREAS NEAR ROCKLAND MAY STAY ON THE WARM SIDE OF THE BOUNDARY AND SEE MAINLY RAIN...IMMEDIATELY ON THE OTHER SIDE OF THE BOUNDARY SEVERAL INCHES OF WET SNOW WILL FALL. I MADE ADJUSTMENTS TO 1ST PERIOD GRIDS BASED ON THE MESONET AND TO REFLECT THE LATEST RADAR TRENDS FOR BANDED PRECIPITATION. ON THE WATERS...WINDS AND SEAS TOUCHED MARGINAL SMALL CRAFT ALONG THE BOUNDARY AND I`VE ISSUED AN SCA FOR AREA OUTSIDE THE BAY FOR THE NEXT FEW HOURS. HRR WINDS WERE USED TO TAILOR WIND GRIDS TO BETTER REFLECT THE COASTAL BOUNDARY. PREV DISC... 640 AM...FORECAST THINKING GENERALLY ON TRACK. ACTUALLY MODELS SEEM TO HAVE A DECENT HANDLE ON THE CURRENT EVENTS...WITH 06Z NAM12 HANDLING THE LARGER SCALE WELL...CAPTURING THE SHRA DEVELOPING OVER CT AND LONG ISLAND SOUND...AND THE RUC PICKING UP ON THE VERY LIGHT SHSN /MAYBE SNIZZLE?/...OVER THE COASTAL PLAIN....WHERE THIS SHOULD REMAIN SPOTTY THRU THE MORNING...AND CHANGE TO RA ON THE COAST....BEFORE STEADIER PRECIP DEVELOPS THIS AFTERNOON. ANY CHANGES TO THE FORECAST BASED ON CURRENT OBS HAVE BEEN MINOR AND ONLY RUN THRU APPROX THE FIRST 6 HOURS OF THE FORECAST. PREVIOUSLY...A SOMEWHAT TRICKY FORECAST TODAY INTO TONIGHT AS VERY WEAK IMPULSES ALOFT...ONE TO OUR S AND ONE TO OUR N PASS THROUGH WITHIN LESS THAN 12 HOURS OF EACH OTHER...ALTHOUGH EITHER ONE IS VERY DYNAMIC. THE FIST ONE...IN THE SRN STREAM ACTUALLY MOVES THROUGH IN THE NEXT FEW HOURS...WITH VERY WEAK SFC REFLECTION...AND LIGHT PRECIP ASSOCIATED WITH WEAK WAA AHEAD OF IT MOVED THRU OVERNIGHT. THE SECOND APPROACHES TODAY...AND GENERATES A BIT MORE LOW TO MID-LVL WAA...WHICH WORKS WITH COASTAL FRONT...AND GENERATES AN INVERTED SFC TROUGH. THIS PRODUCES SOME MORE ORGANIZED FORCING ALONG AND JUST INLAND FROM THE COAST THIS AFTERNOON. WHILE SOME LIGHT PRECIP IS POSSIBLE THIS MORNING...THE BETTER CHC WILL BE THIS AFTERNOON INTO THE EVENING AS THE FORCING INCREASES. THIS PRECIP WILL NOT MOVE IN FROM THE WEST SO MUCH AS IT DEVELOPS ALONG THE COASTAL FRONT. COASTAL AREAS...FIRST TIER OF COASTAL ZONES...ARE LIKELY TO START AS RAIN OR SHIFT TO RAIN QUICKLY...BUT P-TYPE WILL BE SOMEWHAT OF AN ISSUE FOR INLAND AREAS OF THE COASTAL PLAIN. THE COASTAL FRONT WILL MOVE INLAND TODAY...SO SOME AREAS THAT SEE SOME LIGHT SNOW EARLY WILL CHANGE TO RAIN THIS AFTERNOON...AND MOST PLACES IN NH AND FAR WRN ME WILL BE LIMITED TO ABOUT A TENTH OF TOTAL QPF ANYWAY...WHICH WILL LIMIT TO SNOWFALL TO AN INCH OR SO...MAYBE A LITTLE MORE IN THE MTNS...WHERE RATIOS WILL BE HIGHER. MODELS SEEM TO BE FAIR AGREEMENT WHERE HIGHEST QPF WILL OCCUR...MAINLY E OF KPWM-KLEW...WHERE QPF TODAY INTO THIS EVE LOOKS BE 0.3-0.4 INCHES. SO INLAND AREAS OF THE KENNEBEC AND PENOBSCOT VLYS ARE WHERE THE MOST SNOW IS EXPECTED TO FALL. HERE WE ARE LOOKING AT GENERALLY ONE TO THREE INCHES...WITH SOME 4 INCH AMOUNTS POSSIBLE. THE BULLSEYE FOR THE HIGHEST SNOWFALL LOOKS TO BE IN THE SKOWHEGAN-WATERVILLE-UNITY VICINITY. HOWEVER...MODELS ARE FAR FROM PERFECT WHEN IT COMES TO INVERTED TROUGHS...AND THIS COULD END UP SHIFTING A BIT. && .SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 PM MONDAY/... AS THE WEAK 500MB TROUGH ACTUALLY DEEPENS SLIGHTLY JUST TO OUR E LATE TONIGHT...EXPECTING SOME WEAK RIDGING ALOFT TO DEVELOP BEHIND IT FOR MONDAY. WILL LOSE A FEW DEGREES AS WINDS SHIFT N ON THE BACK END OF THE TROUGH...ESPECIALLY IN THE N...AND THIS COULD TURN BACK TO LIGHT SN BEFORE IT ENDS IN ERN ZONES. SO PRECIP IS EXPECTED TO WIND DOWN LATE TONIGHT...WITH A BREAK EXPECTED ON MONDAY...ALTHOUGH WE PROBABLY WILL NOT SEE MUCH SUN ON MONDAY...AS STAGNANT LOW LVL FLOW LINGERS. HIGHS SHOULD CLIMB BACK INTO THE MID 30S TO AROUND 40 AGAIN. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... AS WAS THE CASE THE LAST COUPLE OF NIGHTS...NWP CONTINUES TO INDICATE SRN STREAM S/WV TROF WILL OUTPACE ITS NRN STREAM COUNTERPART. THE RESULT IS LOW PRES DEVELOPING OFF THE SOUTHEAST COASTLINE...AND HEADING OUT TO SEA WITH A LATE CAPTURE THAT SWINGS IT TOWARDS THE CANADIAN MARITIMES. CONSENSUS IS THAT PCPN WILL ONLY BRUSH THE COAST...WITH THE MIDCOAST PERHAPS SEEING A LITTLE LONGER DURATION AS LOW PRES CUTS ACROSS BAROCLINIC ZONE. MODEL GUIDANCE HAS A VERY SHARP NRN EDGE TO THE SATURATED SNOW GROWTH ZONE...SO WE WILL BE TREADING A VERY FINE LINE OF SN OR NO SN HEADING INTO TUE. IN FACT...SFC TEMPS WILL BE MARGINAL ENOUGH THAT SOME RNFL IS POSSIBLE NEAR THE COAST. AS UPPER TROF CROSSES THE AREA THERE SHOULD BE ENOUGH FORCING AND RESIDUAL MOISTURE TO BRING SCT SHSN TO MUCH OF THE AREA BEFORE HIGH PRES BUILDS IN AND ENDS PCPN. THAT RIDGING WILL BE SHORT LIVED THOUGH...AS NEXT LOW PRES DEVELOPS AND LIFTS INTO CANADA. THIS WILL DRIVE A COLD FNT TOWARDS NEW ENGLAND. AFTER INITIAL BURST OF WAA AHEAD OF THE LOW PRES...COLD WILL SLOWLY OOZE INTO THE AREA AS FNT BECOMES ALIGNED WITH FLOW ALOFT. AS LONG AS BOUNDARY REMAINS IN THE AREA IT WILL BE HARD TO RULE OUT OVERRUNNING PCPN IN BROAD SWLY WAA REGIME. LATE IN THE WEEK STRONG HIGH PRES WILL BUILD INTO THE REGION...BEFORE WRN TROF EJECTS NEWD. GIVEN LOCATION OF HIGH PRES...IT WOULD NOT BE SURPRISING TO SEE NWP TREND COOLER WITH TIME...THOUGH THERE ARE SEVERAL DAYS BEFORE ANY DETAILS WILL BECOME MORE CLEAR. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... SHORT TERM...SHOULD SEE ALL TERMINALS GET A PERIOD OF MVFR TO IFR TODAY WITH SHSN INLAND...AND SHRA ON THE COAST. A STEADIER RA IS EXPECTED AT KRKD...AND A STEADY MIX OF RASN AT KAUG. CONDITIONS WILL IMPROVE LATE TONIGHT TO VFR FROM KPWM WWD...AND EVENTUALLY AT KAUG/KRKD ON MONDAY. LONG TERM...AREAS OF MVFR OR LOWER CONDITIONS WILL BE POSSIBLE TUE INTO WED AS OCEAN LOW PRES PASS OUT TO SEA. COASTAL TERMINALS WILL SEE LOWER CIGS AS WELL AS POSSIBLE SHSN LIMITING VSBYS. PASSAGE OF UPPER TROF MAY ALSO RESULT IN SOME MTNS SHWRS INVOF OF KHIE. && .MARINE... SHORT TERM...SOUTHERLY SURGE IN WINDS OCCURRING ATTM AND COULD SEE A FEW GUSTS UP TO 25 KT THRU SUNRISE. OTHERWISE...QUIET WEATHER WITH VSBY RESTRICTIONS EXPECTED LATER TONIGHT THROUGH SUNDAY NIGHT IN DEVELOPING RAIN AND SNOW. LONG TERM...STILL SOME UNCERTAINTY REGARDING THE TRACK OF COASTAL LOW PRES MIDWEEK. HOWEVER CONFIDENCE IS GROWING THAT SEAS WILL BUILD TO AT OR ABOVE 5 FT FOR TUE AND WED. WINDS MORE THAN LIKELY SHOULD REMAIN AT OR BELOW 25 KTS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR ANZ150- 152-154. && $$ ES
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1147 AM EST SUN DEC 1 2013 .SYNOPSIS... LOW PRESSURE IS EXPECTED TO CROSS THE STATE TODAY AND REDEVELOP IN THE GULF OF MAINE TONIGHT, PASSING WELL E OF THE REGION ON MONDAY. ANOTHER LOW MAY AFFECT THE REGION FROM THE SOUTH TOWARD THE MIDDLE PART OF NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... 1145 AM UPDATE...A SMALL BAND OF MODERATE SNOW HAS DEVELOPED ACROSS PORTIONS OF NE AROOSTOOK COUNTY, STRETCHING FROM CARIBOU TO PORTAGE. LOCATIONS UNDER THIS BAND HAVE PICKED UP A QUARTER TO A HALF AN INCH OF NEW SNOW. ANOTHER LARGER AREA OF STEADY SNOW CAN BE SEEN STRETCHING FROM BETWEEN HOULTON AND DANFORTH BACK TOWARD LINCOLN AND DOVER-FOXCROFT. BOTH OF THESE BANDS OF SNOW WILL SLOWLY SINK SOUTHWARD THROUGH THE REMAINDER OF THE AFTERNOON. HAVE UPDATED POPS AND SNOW ACCUMULATIONS TO MATCH THESE TRENDS. ALSO TWEAKED TEMPERATURES A BIT DOWNEAST AS THERE IS A VERY TIGHT GRADIENT BETWEEN THE IMMEDIATE COAST (TEMPS IN UPPER 30S) AND INTERIOR AREAS (BANGOR, WESLEY, AND CHERRYFIELD STILL IN THE LOWER 30S). WITH THIS GRADIENT TO HOLD FAIRLY STEADY, SOME OF THE INTERIOR DOWNEAST COULD SEE SNOW HOLD ON LONGER WITH LITTLE TO NO RAIN, MEANING SNOW AMOUNTS WILL BE A BIT HIGHER. SNOW ACCUMULATIONS WERE ADJUSTED AS NEEDED FOR THIS, AS WELL. NO OTHER CHANGES WERE NEEDED. PREVIOUS DISCUSSION...WEAK LOW PRES MOVING ACROSS THE EASTERN GREAT LAKES IS FCST TO MOVE ACROSS SOUTHERN NEW ENGLAND THIS AFTERNOON AND THEN INTO THE GULF OF MAINE. THE CONCERN IS WHERE TO DRAW THE RAIN/SNOW LINE AS WAA MAKES ITS WAY TO THE BLYR. TEMPERATURES ARE FCST TO REACH INTO THE UPPER 20S TO AROUND 30 ACROSS THE NORTHERN 1/2 OF THE CWA WHILE LOW TO MID 30S ARE EXPECTED FOR CENTRAL AND DOWNEAST AREAS. AN INVERTED TROF EXTENDING FROM THE LOW COMBINED W/SOME FRONTOGENETICAL FORCING AT 1000-700MB WILL LEAD TO A REFORMATION OF PRECIP AND AN ENHANCEMENT OF THE PRECIP. USING THE BUFKIT PROFILES AND SOUNDINGS, THINKING HERE IS THAT SNOW WILL REDEVELOP ACROSS PORTION OF NORTHEAST MAINE W/THE HEAVIEST AXIS ACROSS THE HOULTON AND DANFORTH REGION W/LESS SNOW NORTH AND WEST. S OF OF THE HOULTON-DANFORTH LINE, TEMPERATURES WILL WARM INTO THE MID 30S TO ALLOW FOR SNOW TO MIX WITH AND CHANGEOVER TO RAIN. THIS IN TURN WILL CUT DOWN ON SNOWFALL LATER THIS AFTERNOON INTO TONIGHT. DECISION WAS TO GO AHEAD AND ADD NORTHERN PENOBSCOT AND SE AROOSTOOK COUNTY IN THE WINTER WEATHER ADVISORY THROUGH MONDAY MORNING DUE TO ENHANCED FRONTOGENTICAL FORCING LEADING TO HEAVY SNOW BURSTS. LATEST SNOW TOTAL MAP SHOWS A GENERAL 4-8 INCHES IN THE ADVISORY AREA W/1-4 INCHES N AND W. THE COAST AND EXTREME EASTERN WASHINGTON COUNTY FROM MEDDYBEMPS TO EASTPORT WILL SEE 0.30 TO 0.70 INCHES OF RAINFALL AFTER SOME INITIAL SNOWFALL. SNOW WILL CONTINUE INTO TONIGHT ACROSS THE NORTHEASTERN SECTION OF MAINE INCLUDING CARIBOU-PRESQUE ISLE DOWN THROUGH DANFORTH. WEST OF THIS AREA, LITTLE OR NO SNOW AND RAIN/SNOW S OF THIS AREA W/RAIN FOR THE COAST AS THE WARM AIR IS FCST TO STAY IN. TEMPERATURES WILL DROP BACK INTO THE UPPER TEENS AND LOWER 20S NORTH AND WEST AND MID TO UPPER 20S FOR CENTRAL AREAS. LOW 30S FOR THE DOWNEAST REGION INCLUDING THE COAST. && .SHORT TERM /MONDAY THROUGH TUESDAY/... SNOW WILL CONTINUE TO WIND DOWN EARLY MONDAY AS THE INVERTED TROF EXTENDING FROM THE CANADIAN MARITIMES THROUGH DOWNEAST MAINE MOVES OFF TO THE NORTHEAST. THERE MAY STILL BE SOME LINGERING LIGHT SNOW OR SNOW SHOWERS PARTICULARLY ACROSS EASTERN AREAS OTHERWISE EXPECT MOSTLY CLOUDY SKIES ACROSS THE REGION. MONDAY NIGHT WILL BE MOSTLY CLOUDY BUT DRY AS WEAK HIGH PRESSURE RIDGES DOWN FROM THE NORTH. ATTENTION THEN TURNS TO ANOTHER LOW PRESSURE SYSTEM THAT WILL BE MOVING NORTHEAST ACROSS THE WESTERN ATLANTIC. THIS SYSTEM MAY BRINGS SOME PRECIPITATION TO THE REGION LATER TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... MODELS SEEM TO BE COMING INTO BETTER AGREEMENT FOR THE NEXT SYSTEM TUESDAY NIGHT AND WEDNESDAY. STILL SOME MODEL DIFFERENCES BUT THE CONSENSUS SOLUTION IS FOR THE LOW TO TRACK FAR ENOUGH EAST THAT ANY IMPACTS IN OUR REGION WOULD BE ACROSS DOWNEAST/EASTERN MAINE. A WEAK BOUNDARY WILL CROSS THE REGION BY LATE WEEK WITH SOME SNOW/RAIN SHOWERS POSSIBLE. AGAIN...WILL STICK CLOSE TO THE SUPERBLEND. HIGH PRESSURE WILL BUILD EAST TOWARD THE REGION BY SATURDAY. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... NEAR TERM: MVFR W/PERIODS OF VFR THIS MORNING DROPPING TO MVFR AND EVEN IFR LATER THIS MORNING ON INTO TONIGHT. SNOW ACROSS THE NORTHERN TERMINALS W/SNOW TO RAIN FOR KBGR TO KBHB. SHORT TERM: MVFR CONDS ARE POSSIBLE EARLY MONDAY THEN VFR CONDS EXPECTED MONDAY NIGHT INTO TUESDAY. MVFR CONDS ARE POSSIBLE IN SOME LIGHT PRECIP LATE TUESDAY AND INTO EARLY WEDNESDAY. VFR ON THURSDAY. && .MARINE... NEAR TERM: THE SMALL CRAFT ADVISORY HAS BEEN EXTENDED THROUGH 4 PM THIS AFTERNOON FOR THE OUTER WATERS AS BUOYS ARE STILL REPORTING WINDS GUSTING 20-25 KT AND WAVES 5-6 FT. CONDITIONS IN THE INNER WATERS HAVE IMPROVED, SO THE SCA WAS ALLOWED TO EXPIRE THERE. PREVIOUS DISCUSSION...DECIDED TO GO W/A SCA THROUGH LATE MORNING. WINDS GUSTING TO 25 KTS AS LLVL JET OF 30 KT MOVES ACROSS THE WATERS. THE GFS AND NAM AS WELL AS THE LATEST RAP MODEL PICK UP ON THIS FEATURE. WINDS ARE FCST TO DROP OFF THIS AFTERNOON AS THE LLVL JET SHIFTS TO THE E. SEAS ARE AT 5FT AND COULD TIP 6 FT ESPECIALLY AT 44027(JONESPORT) THIS MORNING. SEAS WILL GRADUALLY SUBSIDE TONIGHT BELOW 4 FT. SHORT TERM: WINDS/SEAS WILL BE BELOW SCA LEVELS MON AND MON NIGHT. WIND/SEAS MAY INCREASE TO SCA LEVELS TUE/TUE NIGHT. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR MEZ005-006- 011-016-017-032. MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ050- 051. && $$ NEAR TERM...HASTINGS/HEWITT SHORT TERM...DUDA LONG TERM...DUDA AVIATION...HASTINGS/HEWITT/DUDA MARINE...HASTINGS/HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1250 PM EST SUN DEC 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 430 AM EST SUN DEC 1 2013 00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER THE UPR GRT LKS TO THE SW OF UPR TROF CENTERED OVER NRN QUEBEC. IN THE WAKE OF DEPARTING SHRTWV MOVING THRU SW QUEBEC...A SHRTWV RDG IS SLIDING SEWD THRU NW ONTARIO...SUPPORTING A SFC HI PRES OVER FAR NW ONTARIO. CLOSER TO UPR MI...A LO PRES TROF IS APRNT NEAR THE LK SUP SHORE OF UPR MI AND EXTENDING WNW IN THE MN ARROWHEAD. THIS TROF HAS BEEN THE FOCUS FOR SOME BANDS OF HIER REFLECTIVITY SHOWN ON THE MQT 88D REFLECTIVITY WITH UPSLOPE N WINDS NEAR LK SUP. SINCE H85 TEMPS ARE ONLY -7 TO -8C AND THE ACCOMPANYING MSTR IS RELATIVELY SHALLOW AS DIAGNOSED FM THE MQT 88D VWP AS WELL AS THE 00Z INL RAOB...WHICH SHOWS INVRN BASE NEAR H85 UNDER VERY DRY MID LVLS AHEAD OF APRCHG SHRTWV RDG...ASSOCIATED PCPN HAS BEEN A MIX OF -SHSN AND SOME -FZDZ. THE 00Z YPL RAOB SHOWS SHALLOW MSTR AS WELL BLO AN INVRN NEAR H925...SO PLENTY OF LO CLDS EXTEND WELL N INTO ONTARIO. THE AIR IS MUCH COLDER THERE WITH SFC TEMPS IN THE TEENS...SO SPOTTY LGT PCPN IS IN THE FORM OF SN. MAIN FCST CONCERN IN THE SHORT TERM IS THE POTENTIAL FOR SOME LGT -SN AND -FZDZ. TODAY...WITH APRCH OF SHRTWV RDG NOW IN NW ONTARIO...LARGER SCALE QVECTOR DVGC/MID LVL DRYING IS FCST TO SLOWLY WEAKEN...BUT NOT ELIMINATE ALTOGETHER...THE SFC TROF NOW OVER LK SUP AND INHIBIT ANY LARGER SCALE PCPN. SFC HI PRES NOW OVER FAR NW ONTARIO IS PROGGED TO DRIFT ONLY SLOWLY SE ACRS NRN ONTARIO...WITH THE CWA DOMINATED BY WEAKENING AND SLOWLY VEERING LLVL NE FLOW. WL CONT TO CARRY SOME CHC POPS NEAR LK SUP IN AREA THAT WL EXPERIENCE AN UPSLOPE WIND COMPONENT NEAR LINGERING LO PRES TROF OVER THE NCENTRAL. WHETHER THIS PCPN IS ALL -SN OR REMAINS MIXED WITH SOME -FZDZ IS THE PRIMARY CONCERN. MODELS REMAIN INCONSISTNET ON FCST H85 TEMPS AND MSTR DEPTH. FCST H85 TEMPS ARE FCST TO FALL TO ARND -9C BY THE 00Z NAM/LOCAL WRF-ARW TO -11C BY THE GFS. GIVEN THE WEAKENING WINDS THAT WL LIMIT LLVL CAD AND EXPECTED NEGATIVE DYNAMICS AS WELL AS UPSTREAM RAOBS...PREFER THE SOMEWHAT WARMER H85 TEMPS AND SHALLOWER MSTR PROFILE/LOWER INVRN BASE SHOWN BY THE 00Z LOCAL WRF-ARW MODEL. THIS MODEL SHOWS THE UPSLOPE UVV AND INVRN BASE REMAINING NR 5K FT AGL AND BLO THE DGZ... SO WL RETAIN A MIX OF -SN/-FZDZ THRU THE DAY. MARGINAL H85 TEMPS RELATIVE TO LK WATER TEMP ARND 4C WL LIMIT ANY SN ACCUM. WITH PLENTY OF LO CLDS...TEMPS SHOULD REBOUND ONLY SLIGHTLY THRU THE DAY. TNGT...VERY LGT LLVL WINDS ARE PROGGED TO SLOWLY VEER TO THE E AND SE AS THE CENTER OF SFC HI PRES SHIFTS INTO QUEBEC. SUSPECT LINGERING LK EFFECT PCPN WL DRIFT INTO THE KEWEENAW AS THE FLOW GRDLY SHIFTS TO THE ESE. IN THE ABSENCE OF ANY DYNAMIC SUPPORT... EXPECT THE INVRN BASE TO REMAIN NEAR 5K FT. AS POINTED OUT BY THE DAYSHIFT...LK VORTICES OFTEN DVLP WITH THE FCST LGT LLVL WINDS. BUT MARGINAL H85 TEMPS ARND -9C WL LIMIT THE INTENSITY OF ANY SHSN THAT WOULD ACCOMPANY THESE FEATURES...AND THE LGT WINDS WL INHIBIT BANDING. SO ANY SN ACCUMS SHOULD REMAIN LGT. SINCE THE H85 TEMPS WL REMAIN MARGINAL FOR LES AND UPSLOPE OMEGA WL REMAIN BLO THE DGZ...INCLUDED A MENTION OF FZDZ. LINGERING LO CLDS WL LIMIT THE DIURNAL TEMP FALL. BEST CHC FOR SOMEWHAT LOWER TEMPS WL BE OVER THE E WITH A RELATIVELY UNMODIFIED/DOWNSLOPE E FLOW OFF ONTARIO THAT MIGHT ALLOW FOR SOME BREAKS IN THE SC. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 430 AM EST SUN DEC 1 2013 MONDAY THROUGH TUESDAY MORNING...UPPER LEVEL 500MB TROUGHING IS EXPECTED TO REMAIN IN PLACE ACROSS THE CWA THROUGH THIS TIME PERIOD AS A WEAK INVERTED RIDGE WEDGES IN ACROSS THE AREA AT THE SURFACE. A SLIGHTLY DRYER AIRMASS WILL ALSO LINGER THROUGH TUESDAY MORNING WHICH CAN BE SEEN BY ANALYZING 1000-500MB RH. THE NEXT SURFACE LOW CAN BE SEEN PUSHING ACROSS THE NORTHERN ROCKIES MONDAY NIGHT AND EJECTING INTO THE NORTHERN OR CENTRAL PLAINS TUESDAY MORNING AS A MUCH DEEPER UPPER LEVEL 500MB TROUGH BUILDS IN OVER THE WESTERN U.S. THERE ARE STILL SOME MODEL DIFFERENCE HOWEVER WITH THE 00Z GFS/NAM BEING A BIT FASTER AND STRONGER WITH THIS LOW. THE 00Z GFS/NAM PLACE THE SURFACE LOW ALONG THE NORTH AND SOUTH DAKOTA BORDER BY 12Z ON TUESDAY. THE 00Z EC/GEM ARE THE SLOWER OF THE SOLUTIONS KEEPING THE LOW A BIT FARTHER SOUTH AND REMAINING OVER THE CENTRAL PLAINS JUST A BIT EAST OF THE ROCKIES. EITHER WAY...BOTH SOLUTIONS KEEP THE PRECIPITATION TO THE WEST OF THE AREA THROUGH THIS TIME PERIOD. LIGHT EASTERLY WINDS THROUGH MONDAY NIGHT WILL SLOWLY BECOME SOUTHEASTERLY BY TUESDAY. THIS ALONG WITH H850 TEMPS AROUND -8 TO -10 C WILL HELP TO KEEP CONDITIONS CLOUDY WITH VERY LIGHT PRECIPITATION POSSIBLE...MAINLY OVER THE KEWEENAW PENINSULA. TUESDAY AFTERNOON THROUGH WEDNESDAY NIGHT...THIS TIME PERIOD REMAINS UNCERTAIN WHICH HAS BEEN THE CASE OVER THE PAST SEVERAL DAYS...WITH POOR MODEL AGREEMENT EVEN AS THIS TIME PERIOD IS RAPIDLY APPROACHING...HOWEVER...THE 00Z EC TENDS TO BE TRENDING A BIT CLOSER TO THE NAM AND GFS SOLUTIONS. THE GFS/NAM SOLUTIONS BRING INCREASED MOISTURE AND PRECIPITATION INTO THE CWA BY 18Z TUESDAY...WHILE THE EC/CANADIAN KEEP THE SYSTEM CENTERED OVER NORTHEASTERN KS DURING THAT TIME FRAME. THE 00Z GFS PLACES THE SURFACE LOW AND VERTICALLY STACKED CLOSED UPPER LEVEL 500MB LOW OVER WESTERN WI AT 00Z WED WHILE THE 00Z EC HAS THE MORE ELONGATED SURFACE LOW OVER CENTRAL IOWA INTO CENTRAL PLAINS. BY 18Z WED THE 00Z RUN OF THE GFS PUSHES THE LOW TO THE NORTHEAST OF LAKE SUPERIOR WHILE THE EC IS JUST PLACING THE SURFACE LOW AND UPPER LEVEL ENERGY INTO THE WESTERN PORTION OF WI. DEFINITELY EASY TO SEE THAT THERE ARE STILL SIGNIFICANT DIFFERENCES BETWEEN THESE MODELS...HOWEVER...A BETTER SIGNAL EXISTS SINCE THE EC IS TRENDING A BIT CLOSES TO THE FASTER SOLUTIONS...THE BEST IDEA FOR THE TIME BEING WILL BE MORE OF A MIDDLE OF THE ROAD APPROACH...WITH A SLIGHT LEAN TOWARD THE FASTER SOLUTIONS. THIS WOULD FAVOR A LATE TUESDAY NIGHT THROUGH WEDNESDAY NIGHT TIME FRAME FOR THE MORE CONCENTRATED AREA OF PRECIPITATION. SOUNDINGS FOR THIS TIME PERIOD INDICATE WARMER AIR LIFTING NORTHWARD ON THE EAST SIDE OF THE LOW HELPING TO TRANSITION THE PRECIPITATION OVER TO A RAIN SNOW MIXTURE FOR AT LEAST THE EASTERN HALF OF THE UPPER PENINSULA AS A FAIRLY DEEP WARM LAYER BUILDS IN THROUGH MUCH OF THE BOUNDARY LAYER. THE FAR WESTERN PORTION OF THE U.P. MAY END UP SEEING MAINLY SNOW AS SHOWN BY ANALYZING BOTH THE EC AND GFS PROFILES. IN ANY CASE THIS SYSTEM WILL BE CLOSELY WATCHED OVER THE NEXT SEVERAL MODEL RUNS TO SEE IF BETTER UPPER AIR SAMPLING CAN ENTERTAIN GREATER MODEL AGREEMENT. THURSDAY THROUGH SATURDAY...ATTENTION TURNS TO A POTENTIALLY PROLONGED PERIOD OF LAKE EFFECT SNOW. MODELS ACTUALLY BECOME IN BETTER AGREEMENT WITH THE SYSTEM DURING THIS TIME FRAME. EACH OF THE MODELS SHIFT THE SURFACE LOW NORTHEASTWARD TO NEAR JAMES BY BY 12Z THURSDAY. AS THIS HAPPENS WINDS WILL SHIFT TO THE WEST ALLOWING LAKE EFFECT SNOW TO DEVELOP IN AREAS FAVORED BY THAT PARTICULAR WIND DIRECTION. THURSDAY THROUGH THURSDAY NIGHT THE LAKE EFFECT SNOW WILL PROBABLY JUST BE STARTING ACROSS THE AREA...BUT SHOULD REMAIN LIGHT. TRIED TO TREND THE LES CHANCES UPWARD FRIDAY THROUGH SATURDAY AS AN UPPER LEVEL TROUGH/SHORTWAVE AND INCREASED MOISTURE SHIFTS INTO THE AREA...ALLOWING FOR ENHANCED LIFT FOR LES TO DEVELOP. ITS STILL A BIT TOO EARLY TO TELL FOR SURE ABOUT THE OVERALL SNOWFALL TOTALS...BUT IT DOES LOOK LIKE FRIDAY INTO SATURDAY WILL BE SNOW FOR WESTERLY WIND FAVORED AREAS OF THE UPPER PENINSULA. AS EARLIER SHIFT STATED THE SNOW TO LIQUID RATIOS WILL LIKELY BE SLIGHTLY LOWER THAN USUAL FOR LES AS THE DGZ IS FAIRLY SHALLOW AND FAIRLY LOW IN THE ATMOSPHERE...WHICH TENDS TO INHIBIT THE MORE FAVORABLE GROWTH RATES FOR SNOW. STAY TUNED THOUGH AS THIS LES EVENT GETS CLOSER TOWARD THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1248 PM EST SUN DEC 1 2013 A MVFR/VFR STRATUS DECK COVERS ALL OF UPPER MICHIGAN THIS AFTERNOON AND WITH LIGHT NORTHERLY WINDS...EXPECT THAT TO CONTINUE INTO THE EVENING HOURS. THERE COULD BE SOME BRIEF VISIBILITY RESTRICTIONS AS KSAW LATE THIS AFTERNOON...AS A LAKE EFFECT BAND IN EASTERN ALGER COUNTY DROPS SOUTHEAST. LATEST TRENDS ARE FOR SOME WEAKENING AND WITH WINDS ALOFT WEAKENING AND BECOMING VARIABLE...IT MAY NOT EVEN MAKE IT THERE. AS LOW LEVEL WINDS BEGIN TO TRANSITION TO THE SOUTH THIS EVENING AND OVERNIGHT...EXPECT THE LINGERING LAKE EFFECT TO SHIFT NORTH AND POTENTIALLY BRUSH KCMX. THIS SOUTHERLY WIND WILL LIKELY LEAD TO CEILINGS RISING TOWARDS VFR OVERNIGHT INTO MONDAY MORNING...BUT CONFIDENCE IS VERY LOW ON HOW QUICKLY THAT WILL OCCUR. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 430 AM EST SUN DEC 1 2013 EXPECT NE WINDS UP TO 20 KTS EARLY THIS MORNING TO DIMINISH UNDER 15 KTS AND SLOWLY VEER INTO MON AS A WEAK PRES GRADIENT EXTENDING S FROM HI PRES MOVING THRU ONTARIO DOMINATES THE UPPER LAKES. STRONGER E TO SE WINDS UP TO 25 TO PERHAPS 30 KTS WILL THEN DEVELOP INTO MID WEEK AS THE GRADIENT SHARPENS OVER LAKE SUP BETWEEN THE HI PRES SHIFTING INTO QUEBEC AND LO PRES MOVING NE FROM THE PLAINS. THERE WILL BE A SHARP WIND SHIFT TO THE WNW BY THU FOLLOWING THE PASSAGE OF THE LO TO THE NE. DEPENDING ON THE TRACK AND INTENSITY OF THIS LO...THERE COULD BE A W GALE ON THU INTO FRI. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...KC LONG TERM...KEC AVIATION...SRF MARINE...KC
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1148 AM CST Sun Dec 1 2013 .SHORT TERM: (Through Late This Afternoon) Issued at 335 AM CST Sun Dec 1 2013 Think the challenge for today will be forecasting cloud cover. A stratus deck between 4000-5000ft is moving across he eastern Ozarks and parts of Southern Illinois this morning. Think this area of stratus will continue advecting eastward faster than the western edge will erode as has been the case for the past few hours. Therefore there should be substantial cloud cover over southeast Missouri and parts of southern Illinois this morning. The 00Z NAM eventually cleared it out and this matches well with satellite trends at this time; however the RAP backbuilds the cloud cover, as does the 06Z NAM and this suggests that areas generally southeast of a line from Vichy, MO to Salem, IL may not see much sun today. Am sticking closer to the less cloudy solution at this time, but this may ultimately prove to be too optimistic. Temperatures may be challenging as well. Can`t seem to forecast warm enough the past couple of days. Missed highs both Friday and Saturday by to to three degrees. Lingering cloud cover over the eastern Ozarks and southwest Illinois may make this especially challenging. For highs today, used a blend of 925 mix-down temperatures and MOS. Tweaked southern zones down a couple of degrees from that to account for cloud cover, and the rest of the area up a degree or two to try to compensate for my apparent cool bias. Britt .LONG TERM: (Tonight through Saturday) Issued at 335 AM CST Sun Dec 1 2013 (Tonight - Tuesday) Have not made too many changes to going forecast during this period. Low level moisture progs suggest that stratus will redevelop this evening, particularly over the southern and eastern part of the CWA. Have kept chance of light drizzle in these areas where this moisture will be the deepest and there will be some very light ascent. As we go into Monday, GFS/NAM/ECMWF all show a weak shortwave trough racing into the area from the west, though it is not as deep as was forecast 24 hours ago. Have left chance of sprinkles in for tomorrow morning as the trough axis will move through the area by midday. Temperatures will begin to warm up ahead ahead of the next storm system. Expect temperatures to climb into the 50s on Monday with some spots reaching 60 on Tuesday. (Wednesday - Saturday) Main concern continues to be the potential for a wintry precipitation and the big cool down mid to late week. There still ia a great deal of uncertainty regarding timing, precipitation types and amounts. While the GFS is still the fastest with the passage of the cold front, the 00Z ECMWF now brings the cold front through the area during the day on Wednesday instead of Wednesday Night. The cold front will have moved to the south of the area Wednesday. Best forcing for precipitation will hinge on mid-level frontogenesis and shortwave troughs moving through fast west- southwesterly flow aloft. Have likely pops on Thursday and Thursday Night over southeastern half of the CWA with the chance continuing into Friday. Will continue to have a simple mix of rain and snow because of the uncertainty for now, but thermal profiles from forecast soundings certainly suggest the potential for sleet or freezing rain over the southern half of the CWA. 850mb temperatures by next Friday and Saturday will be in the -10 to -12C range supporting highs only in the 20s with lows in the single digits and teens. Britt && .AVIATION: (For the 18z TAFs through 18z Monday Afternoon) Issued at 1050 AM CST Sun Dec 1 2013 Very weak cold front has just pushed se of CPS late this mrng. Only expect light nely sfc winds at UIN and COU this aftn, and nwly in the St Louis metro area veering around to a nely direction by early evng. The sfc wind will remain light tgt and continue to veer around to an e-sely direction by late tgt as the sfc ridge over the nrn Plains moves ewd through the Great Lakes region. The sfc wind will strengthen some from a sely direction Monday mrng. Mid-high level clouds will advect into the region tgt. It appears that there will be patchy fog and stratus clouds redeveloping late tgt. The best potential for stratus clouds may be south of the taf sites, but there will likely be at least light fog impacting the COU and St Louis areas and possibly also UIN as well. Specifics for KSTL: Light nwly sfc wind this aftn will gradually veer around to a nely direction by this evng, e-sely direction by late tgt, then strengthen to 7-9 kts from a s-sely direction Monday aftn. Mid-high level cloudiness will advect into STL by late tgt. May also have some light fog late tgt/early Monday mrng as well as patchy stratus clouds mainly Monday mrng. GKS && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
325 PM MST SUN DEC 1 2013 .DISCUSSION... MAIN FORECAST CHALLENGE IN THE SHORT-TERM CONTINUES TO BE NAILING DOWN WHEN THE PERSISTENT LOW CLOUD DECK OVER NW AND WEST CENTRAL NM WILL SCOUR OUT OF THE AREA. THE VAST MAJORITY OF MODEL GUIDANCE DID NOT SHOW THESE CLOUDS CONTINUING TO PLAGUE THE AREA TODAY BUT ALAS THEY ARE STILL HOLDING STRONG. THE RUC13 WAS THE BEST TO HOLD ONTO SATURATION IN THE NEAR SURFACE LAYER AND INDICATIONS ARE THAT IT WILL CONTINUE TONIGHT AND EARLY MONDAY. WINDS ALOFT AND EVEN AT THE SURFACE ARE INCREASING HOWEVER IT IS POSSIBLE THE THICK/PERSISTENT LOW CLOUD DECK IS FEEDING BACK TO STRENGTHEN LOW LEVEL INVERSIONS AND KEEP A VERY SHALLOW BOUNDARY LAYER DECOUPLED. OTHER INTERESTING ITEM WILL BE WHETHER LOW CLOUDS CAN SEEP OVER THE WEST MESA AND END UP IN THE MIDDLE RIO GRANDE VALLEY TONIGHT AS INCREASING NW FLOW ADVECTS THE LAYER SE. BEST SHOT WILL BE WEST SIDE SO HAVE INCREASED TO MOSTLY CLOUDY THERE OVERNIGHT. CONSIDERABLE DIFFERENCES REMAIN WITH MODEL GUIDANCE ON THE DETAILS OF THE NEXT SIGNIFICANT STORM SYSTEM BEYOND WEDNESDAY. FIRST WE HAVE TO DEAL WITH SOME WIND. NW FLOW OVER THE REGION TODAY WILL BACK TO WEST AND INCREASE TUESDAY. 700-500MB LAYER WINDS BTWN 50 AND 60KTS WILL COMBINE WITH A SURFACE LOW OVER THE PLAINS TO CREATE STRONG WEST WINDS ALONG AND EAST OF THE CENTRAL MT CHAIN. IT IS STILL A LITTLE EARLY BUT BETS ARE GOOD ON A HIGH WIND WATCH FROM THE FOLLOWING SHIFT FOR TUESDAY. HEIGHT FALLS AND COLD ADVECTION WILL BEGIN TUESDAY NIGHT ACROSS THE WEST AS THE JET AXIS DEPARTS TO THE EAST. MEANWHILE...THE PLAINS PORTION OF AN ARCTIC AIRMASS WILL BE SHIFTING SOUTH TOWARD THE NE PLAINS. MODELS THEN STRUGGLE CONSIDERABLY DEALING WITH THE APPROACH OF A SHEARING UPPER TROUGH AXIS OVER THE WESTERN CONUS WEDNESDAY AND THURSDAY AND THE DEGREE OF MOISTURE ASSOCIATED WITH IT. A REALLY GOOD CERTAINTY IS THAT IT IS GOING TO GET VERY COLD. AT THIS TIME THE SUITE OF ENSEMBLE AND WPC GUIDANCE SHOWS THE PLAINS PORTION OF THE ARCTIC AIRMASS SETTLING ONTO THE EAST SLOPES OF THE CENTRAL MT CHAIN WHILE THE SECOND PORTION SHIFTS SOUTH THRU THE INTERMOUNTAIN WEST. 700MB TEMPS BTWN -10 AND -14C WITH THIS AIRMASS ARE 1 TO 2 STANDARD DEVIATIONS BELOW CLIMO AND RESULTS IN HIGH TEMPS 15 TO 25 F BELOW NORMAL ALL AREAS. QPF AND SNOW IMPACTS WILL BE THE GREATEST CHALLENGE WITH THIS SYSTEM. MODELS AGREE A BAND OF SNOW WILL SHIFT SE OVER WESTERN NM WEDNESDAY THEN DISSIPATES WEDNESDAY NIGHT...WHILE LOW CLOUDS AND LIGHT SNOW OR FLURRIES IMPACT THE EAST. THE GFS IS THEN THE MOST BULLISH BREAKING OUT A LARGE AREA OF LIGHT/MODERATE SNOW ALONG AND EAST OF THE CONT DVD THURSDAY THEN TAPERS OFF INTO THE EAST FRIDAY. AT THIS TIME IMPACTS TO TRAVEL MAY BE HIGH WITH EVEN LIGHT AMOUNTS OF PRECIP DUE TO THE SEVERITY OF THE COLD AND BLOWING SNOW. BELIEVE OR NOT MODELS ARE ADVERTISING AN EVEN COLDER SECOND ARCTIC AIRMASS TO SHIFT SOUTH OVER THE WESTERN CONUS MONDAY AND TUESDAY OF NEXT WEEK. 700MB TEMPS OVER NORTHERN NM ARE ADVERTISED BY THE ECMWF TO FALL TO -24C WHICH IS EXCEPTIONALLY COLD. ANOTHER ROUND OF SNOW IS ALSO ADVERTISED. GUYER && .FIRE WEATHER... MAIN FIRE WEATHER ISSUES NEXT FEW DAYS WILL BE THE STRONG INVERSIONS IN PLACE ACROSS ROUGHLY THE NW QUARTER TO THIRD OF THE STATE... EMPHASIZING THE NW AND WEST CENTRAL VALLEYS TO THE WEST OF THE CONTINENTAL DIVIDE. THIS WILL CONTINUE QUITE STRONG THROUGH TONIGHT AND MON MORN...IMPROVING SOME MON AFTN AND RETURNING MORE WEAKLY MON NIGHT INTO TUE MORN. AS A RESULT VENTILATION RATES TO REMAIN MAINLY POOR IN THIS AREA THROUGH MON NIGHT. ACCOMPANYING THIS WILL BE VERY LOW CLOUD DECK AND FREEZING FOG TONIGHT AND WELL INTO MON MORN. OTHER SIGNIFICANT FIRE WX CONCERN WILL BE RISK OF MARGINALLY CRITICAL FIRE WEATHER CONDITIONS FOR PERHAPS 2 OR 3 HOURS TUE AFTN IN MAINLY SOUTHERN PORTION OF ZONE 108 IN EAST CENTRAL NM. MAIN LIMITING ISSUE WILL BE THE MINIMUM RH. OUTSIDE OF THE ABOVE MENTIONED AREAS...OVERNIGHT HUMIDITY RECOVERY WILL STILL BE VERY GOOD TO EXCELLENT IN THE ESTANCIA AND UPPER RIO GRANDE VALLEYS. HOWEVER...RECOVERIES WILL NOT BE AS HIGH IN THE EASTERN PLAINS...MAINLY 45 TO 55 PERCENT. SCATTERED LOCALES ALONG THE CENTRAL MOUNTAIN CHAIN AND CENTRAL HIGHLANDS WILL EXPERIENCE BREEZY TO OCCASIONALLY WINDY CONDITIONS THROUGHOUT THE NIGHT AND INTO MON. STILL...POOR VENTILATION/DISPERSION IS EXPECTED WEST OF CENTRAL MTN CHAIN THROUGH MON NIGHT WITH TEMPERATURES RISING A COUPLE TO SEVERAL DEGREES OVER TODAY. EAST OF CENTRAL MTN CHAIN EXPECT FAIR TO LOCALLY VERY GOOD VENT RATES MON AFTN. FLOW ALOFT BECOMES MORE WESTERLY MON NIGHT AND WEST SOUTHWESTERLY BY TUE NIGHT AS LONGWAVE TROUGH ESTABLISHES TO THE WEST OF NM. AS WINDS DRAMATICALLY INCREASE ALOFT THE 10000 FT LEVEL WINDS ARE LIKELY TO REACH 45 TO 65 KT...PERHAPS EVEN A BIT HIGHER...ON MUCH OF THE HIGHER TERRAIN. STRONG BUT RATHER SHALLOW BACK DOOR FRONT LIKELY TO ENTER FAR NE NM LATE TUE OR EARLY WED WITH THE USUAL TIMING DIFFERENCES BETWEEN THE MODELS. STRONG WINDS WILL REMAIN A CONCERN FOR HIGH TERRAIN AREAS TUE. AHEAD OF THE FRONT THE EASTERN PLAINS WOULD GET SOME DOWNSLOPING WARMING EFFECTS...AS TEMPS RUN 8 TO 15 DEGREES ABOVE AVERAGE WITH HUMIDITY OF 15 TO 20 PERCENT TUE AFTN. BREEZY TO WINDY CONDITIONS WILL LIKELY PERSIST INTO WED...ESPECIALLY THE HIGH TERRAIN ZONES...WHILE MUCH COLDER AIR SPILLS INTO THE STATE FROM THE NE AND NW. SOME LIGHT TO LOCALLY MODERATE PRECIPITATION WILL ALSO BE POSSIBLE ACROSS FCST AREA WED...SPREADING FARTHER EAST THU AND FRI. PREFERRED AREAS WILL BE NW TWO THIRDS OF THE STATE. BY THU THE ENTIRE FORECAST AREA TEMPS LIKELY TO FALL TO BETWEEN 10 AND 30 DEGREES BELOW AVERAGE. LITTLE IF ANY MODERATION FROM THE WELL BELOW NORMAL TEMPS FRI. VENTILATION WILL SEE A MAJOR BOOST TUE AND WED...BUT THEN STEADILY LOWER THU INTO FRI. 43 && .AVIATION... 18Z TAF CYCLE LOW CLOUDS AND FOG HANGING VERY TOUGH OVER NORTHWEST AND WEST CENTRAL NM. UPDATED SKY COVER TO KEEP LOW CLOUDS OVER THE AREA DESPITE MOST MODEL GUIDANCE SCOURING OUT CLOUD COVER. LATEST VISIBLE SATELLITE IMAGERY SHOWS AREA ACTUALLY EXPANDING SLIGHTLY. ALSO NEEDED TO LOWER MAX TEMPS QUITE A BIT ACROSS THIS AREA AS VERY LITTLE WARMING IS NOW EXPECTED. LOW CLOUDS MAY EVEN STAY IN PLACE TONIGHT SINCE THE AREA IS LIKELY PROVIDING A FEEDBACK TO VERY STRONG INVERSIONS IN PLACE. BY MONDAY ATMOSPHERIC WINDS AND THE SURFACE PRESSURE GRADIENT BEGIN INCREASING AHEAD OF A STRONG PACIFIC FRONT FOR LATE TUESDAY/WEDNESDAY. 43 && .PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 28 44 28 50 / 0 0 0 0 DULCE........................... 20 47 21 44 / 0 0 0 10 CUBA............................ 25 50 25 49 / 0 0 0 0 GALLUP.......................... 24 52 24 50 / 0 0 0 0 EL MORRO........................ 23 51 24 48 / 0 0 0 0 GRANTS.......................... 23 54 24 52 / 0 0 0 0 QUEMADO......................... 26 55 27 54 / 0 0 0 0 GLENWOOD........................ 30 64 29 59 / 0 0 0 0 CHAMA........................... 17 44 19 37 / 0 0 0 20 LOS ALAMOS...................... 27 49 28 47 / 0 0 0 0 PECOS........................... 31 49 30 44 / 0 0 0 0 CERRO/QUESTA.................... 7 42 11 38 / 0 0 0 0 RED RIVER....................... 16 40 18 35 / 0 0 5 0 ANGEL FIRE...................... 23 42 24 38 / 0 0 0 0 TAOS............................ 12 45 16 43 / 0 0 0 0 MORA............................ 27 51 28 47 / 0 0 0 0 ESPANOLA........................ 24 51 26 50 / 0 0 0 0 SANTA FE........................ 27 48 27 45 / 0 0 0 0 SANTA FE AIRPORT................ 27 52 27 50 / 0 0 0 0 ALBUQUERQUE FOOTHILLS........... 33 55 33 56 / 0 0 0 0 ALBUQUERQUE HEIGHTS............. 33 57 34 57 / 0 0 0 0 ALBUQUERQUE VALLEY.............. 31 58 30 59 / 0 0 0 0 ALBUQUERQUE WEST MESA........... 31 58 32 59 / 0 0 0 0 LOS LUNAS....................... 30 58 29 61 / 0 0 0 0 RIO RANCHO...................... 31 57 32 58 / 0 0 0 0 SOCORRO......................... 33 61 33 65 / 0 0 0 0 SANDIA PARK/CEDAR CREST......... 31 52 32 53 / 0 0 0 0 TIJERAS......................... 32 54 33 54 / 0 0 0 0 MORIARTY/ESTANCIA............... 25 50 27 49 / 0 0 0 0 CLINES CORNERS.................. 31 51 32 50 / 0 0 0 0 GRAN QUIVIRA.................... 34 53 33 54 / 0 0 0 0 CARRIZOZO....................... 34 59 33 58 / 0 0 0 0 RUIDOSO......................... 39 60 39 57 / 0 0 0 0 CAPULIN......................... 30 58 31 51 / 0 0 0 0 RATON........................... 28 60 29 54 / 0 0 0 0 SPRINGER........................ 27 62 28 56 / 0 0 0 0 LAS VEGAS....................... 30 60 31 51 / 0 0 0 0 CLAYTON......................... 35 66 36 56 / 0 0 0 0 ROY............................. 34 65 35 59 / 0 0 0 0 CONCHAS......................... 37 67 37 63 / 0 0 0 0 SANTA ROSA...................... 40 66 40 64 / 0 0 0 0 TUCUMCARI....................... 37 69 38 68 / 0 0 0 0 CLOVIS.......................... 39 66 40 67 / 0 0 0 0 PORTALES........................ 41 68 41 68 / 0 0 0 0 FORT SUMNER..................... 42 68 42 69 / 0 0 0 0 ROSWELL......................... 42 74 42 77 / 0 0 0 0 PICACHO......................... 42 70 42 67 / 0 0 0 0 ELK............................. 42 67 42 62 / 0 0 0 0 && .ABQ WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1203 AM EST SUN DEC 1 2013 .SYNOPSIS... LOW PRESSURE WILL GRADUALLY DEVELOP OFF THE CAROLINA COAST LATE TODAY INTO TONIGHT...MOVING OUT TO SEA MONDAY. WEAK HIGH PRESSURE WILL MOVE ACROSS THE AREA TUESDAY AND OFFSHORE WEDNESDAY...BRINGING SEVERAL DAYS OF WARM TEMPERATURES LATE THIS WEEK. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1230 PM SUNDAY...CHANGES WITH THIS EARLY AFTERNOON UPDATE INCLUDING TRIMMING BACK POPS EVEN FURTHER...WITH THE CHANCE OF MEASURABLE PRECIPITATION NOW CONFINED TO AREAS ALONG AND EAST OF MYRTLE BEACH...ACME/DELCO...AND BURGAW. ON LAND MY HIGHEST POPS THROUGH THE AFTERNOON REMAIN ON THE TIP OF CAPE FEAR...ABOUT A 40 PERCENT CHANCE OF 0.01 INCHES OR MORE REACHING THE BOTTOM OF A HYPOTHETICAL RAIN GAUGE. NO SIGNIFICANT CHANGES HAVE BEEN MADE TO SKY COVER OR TEMPERATURES. PREVIOUS DISCUSSION FROM 930 AM FOLLOWS... MODELS OVER THE PAST TWO DAYS HAVE DONE AN ABYSMAL JOB FORECASTING HOW THE WEATHER HAS ACTUALLY UNFOLDED OVER THE PAST 6-12 HOURS. NOT ONLY IS ISENTROPIC LIFT STRONGER AND COVERAGE OF SHOWERS MORE WIDESPREAD NOW OVER THE COASTAL WATERS THAN WAS EXPECTED...BUT THE 06Z GFS AND NAM PLUS THE 12Z RUC PAINT A PICTURE OF DRIER WEATHER DEVELOPING INTO TONIGHT AS WHAT ISENTROPIC LIFT WE CURRENTLY HAVE TRICKLES OFFSHORE AND DRIER AIR ARRIVES FROM THE WEST AND SOUTHWEST WITHIN THE 5000-10000 FOOT LAYER. COMPARED TO 12Z SOUNDINGS ALL THE MODELS ARE STRUGGLING WITH WHAT IS GOING ON BELOW 10000 FEET THIS MORNING. THIS WAS PARTICULARLY APPARENT AT CHS WHERE THE GFS HAD A HORRIBLE HANDLE (TOO WET) ON MOISTURE WITHIN THE 800-900 MB LAYER. ALL THE MODELS FAILED TO PROPERLY SHOW WARM TEMPERATURES BETWEEN 850-1000 MB OBSERVED ON THE MHX SOUNDING. NEEDLESS TO SAY...THIS CASTS DOUBT ON WHAT (IF ANY) MODEL GUIDANCE IS TRUSTWORTHY GOING FORWARD THROUGH THIS AFTERNOON INTO TONIGHT. MY CURRENT IDEA (BASED ON CURRENT RADAR AND SATELLITE IMAGERY SPRINKLED WITH RUC/HRRR GUIDANCE THROUGH THE AFTERNOON) IS FOR A MUCH DRIER AFTERNOON THAN WAS EXPECTED. I HAVE REMOVED POPS FOR THE PEE DEE COUNTIES IN SOUTH CAROLINA AND TRIMMED BACK POPS ALONG THE COAST TO NO HIGHER THAN 30-40 PERCENT...HIGHEST ACROSS SOUTHPORT/ CAROLINA BEACH. WITH NO PRECIPITATION INLAND AND SATELLITE IMAGERY SHOWING BREAKS IN THE OVERCAST ACROSS MUCH OF CENTRAL AND EASTERN SOUTH CAROLINA I HAVE RAISED FORECAST HIGHS BY 3-4 DEGREES FROM FLORENCE TO LUMBERTON...WITH UPPER 50S EXPECTED FOR MOST AREAS THIS AFTERNOON. DRIER AIR ARRIVING THIS AFTERNOON WITHIN THE LAYER CURRENTLY GENERATING ISENTROPIC LIFT AND SHOWERS (6000-10000 FT) SHOULD LEAD TO DRY CONDITIONS EVEN ALONG THE COAST. SURPRISINGLY... THIS DRIER TREND MAY EVEN CONTINUE INTO TONIGHT AS THE 06Z MODELS (FOR WHAT THEY`RE WORTH) SHOWING SHOWERS REMAINING MAINLY OFFSHORE. LET`S HOPE THE 12Z RUNS CAN LEND A HAND WITH THAT PORTION OF THE FORECAST. && .SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...A SLEW OF SHORTWAVES WILL CROSS THE CAROLINAS, GA, AND NRN FL ON MONDAY...SOMEWHAT CONGEALING OFF THE SOUTHEAST COAST LATE IN THE DAY. THE RESULTING SURFACE WAVE OF LOW PRESSURE THAT HAD BEEN PROGGED TO DEVELOP NOW LOOKS CONSIDERABLY WEAKER. MORNING RAIN CHANCES ASSOCIATED WITH THIS FEATURE WILL BE FOCUSED ALONG THE CAPE FEAR/COASTAL NC ZONES BEFORE DECREASING PERHAPS RAPIDLY LATER IN THE DAY AS DIFFERENTIAL VORTICITY ADVECTION TURNS QUITE NEGATIVE AND THE LOW LEVEL UPGLIDE LOOKS TO SHUT OFF AS WELL. TUESDAY THEN BRINGS ZONAL MID LEVEL FLOW THAT SHOULD KEEP THINGS DRY. AT THE SURFACE THERE WILL WON`T BE MUCH GRADIENT AS A WEAK HIGH OVER THE CAROLINAS FILLS THE SPACE IN BETWEEN THE DEEPENING ATLANTIC LOW AND A LARGE SYSTEM GATHERING STRENGTH OVER THE NRN PLAINS. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... AS OF 3 AM SUNDAY...RIDGE AXIS TO DRIFT OFFSHORE ON WEDNESDAY PAVING THE WAY FOR SOME RETURN FLOW. EXPECT ABOVE NORMAL HIGHS FOR THE FIRST TIME IN QUITE A WHILE DESPITE POSSIBLE INCREASE IN LOW TO MID LEVEL CLOUDINESS. THURSDAY TOO WILL BE MILD AND RATHER CLOUDY AS THE RETURN FLOW VEERS SOMEWHAT DUE TO THE APPROACH OF A COLD FRONT FROM THE WEST. THE NE TO SW ORIENTATION OF THE BOUNDARY WILL HAVE IT QUITE LINED UP WITH THE MID LEVEL FLOW MAKING FOR VERY SLOW PROGRESSION. IN FACT WE SEE SOME DIFFERENCES IN THE SPEED AT WHICH THE BOUNDARY APPROACHES AND MOVES THROUGH BETWEEN VARIOUS MODELS. GIVEN THE VERTICAL DIRECTIONAL ALIGNMENT OF THE FLOW THE SLOWER SOLUTIONS SEEM MORE PLAUSIBLE. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... AS OF 18Z...MODERATE UNCERTAINTY WITH RESPECT TO CLOUD HEIGHTS. A COASTAL LOW TRIES TO FORM OVERNIGHT...BUT IT WILL NOT PHASE UNTIL LATE MONDAY...AFTER IT IS WELL NORTHEAST OF THE REGION. ANY PRECIP ASSOCIATED WITH IT THIS AFTERNOON WILL BE VERY LIGHT AND PROBABLY WILL NOT AFFECT VISIBILITY. THINK THE CEILINGS WILL FALL DIURNALLY THIS EVENING...PERHAPS IFR AT THE MYRTLES MOST OF THE NIGHT. LIGHT WINDS OVERNIGHT WILL BECOME NORTHERLY MONDAY AFTER THE LOW PULLS TO THE NORTHEAST. CEILINGS SHOULD IMPROVE TO VFR...HOWEVER IT MAY TAKE A FEW HOURS AFTER DAYBREAK TO ACCOMPLISH THIS. EXTENDED OUTLOOK...MAINLY VFR TUESDAY AND WEDNESDAY. LOW CONFIDENCE FOR SHOWERS THURSDAY AND FRIDAY...MAINLY WEST. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1230 PM SUNDAY...NO SIGNIFICANT CHANGES ARE NEEDED FOR THIS EARLY AFTERNOON UPDATE. PREVIOUS DISCUSSION FROM 930 AM FOLLOWS... FAIRLY WIDESPREAD SHOWER ACTIVITY COVERS THE OUTER PORTION OF THE COASTAL WATERS THIS MORNING...EXCEPT NEAR CAPE FEAR WHERE THE SHOWERS ARE ALSO OCCURRING IN THE NEARSHORE WATERS. THIS IS OCCURRING IN ASSOCIATION WITH A WEAK COASTAL TROUGH NEAR THE WESTERN EDGE OF THE GULF STREAM. NORTH WINDS SHOULD VEER A LITTLE MORE NORTHEASTERLY BY THIS AFTERNOON...WITH NO INCREASE IN WIND SPEEDS EXPECTED. SEAS ARE THE BIG STORY AWAY FROM SHORE AS A PERSISTENT 9-SECOND EASTERLY SWELL CONTINUES TO BRING SIGNIFICANT WAVE ENERGY INTO THE AREA. THE GENESIS REGION FOR THIS SWELL IS ACTUALLY WELL OUT INTO THE CENTRAL ATLANTIC WHERE A COUPLE THOUSAND MILES OF EASTERLY FLOW ALONG THE SOUTH SIDE OF NORTH ATLANTIC HIGH PRESSURE IS BUILDING QUITE A WAVE FETCH. SEAS OUT AT FRYING PAN SHOALS ARE AROUND 5 FEET DUE TO THIS SWELL...WITH 3 FEET REPORTED AT THE BUOY SEVERAL MILES SOUTH OF THE MOUTH OF THE CAPE FEAR RIVER. SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/... AS OF 3 AM SUNDAY...A SERIES OF CONGEALING UPPER LEVEL DISTURBANCES WILL FORM A SURFACE LOW OFF THE COAST BY MONDAY MORNING. THIS FEATURE IS NOW SUPPOSED TO BE WEAKER THAN EARLIER FORECASTS AND POSSIBLY FURTHER OUT TO SEA AS WELL. THIS INCREASES FORECAST CONFIDENCE THAT NO ADVISORIES OR HEADLINES WILL BE NEEDED AT THIS TIME AS WINDS MAY BE CAPPED IN THE 10 TO 15 KT RANGE OVER NORTHERN ZONES WITH PERHAPS JUST 10 KT SOUTH. EVEN LIGHTER WINDS AND SEAS MAY BE IN THE OFFERING ON TUESDAY AS THIS SYSTEM EXITS AND ANOTHER DEVELOPS OVER THE NORTHERN PLAINS...WITH ONLY A WEAK HIGH IN BETWEEN OVER THE CAROLINAS. LONG TERM /WEDNESDAY THROUGH THURSDAY/... AS OF 3 AM SUNDAY...WIND SWINGS AROUND TO THE SOUTH ON WEDNESDAY AS THE CENTER OF HIGH PRESSURE MOVES OFF THE COAST. NO REAL INCREASE IN WIND SPEED TO SPEAK OF HOWEVER SO SEAS MAY ACTUALLY CONTINUE TO SETTLE SOME FROM THEIR TUESDAY VALUES. A COLD FRONT WILL APPROACH FROM THE NW ON THURSDAY ALBEIT QUITE SLOWLY AS THE BOUNDARY WILL BE ALIGNED WITH ITS MID LEVEL STEERING FLOW. THE SLOW APPROACH OF THE FRONT WILL VEER THE WIND SLIGHTLY AND YIELD A GRADUAL INCREASE IN WIND SPEED. THIS WILL CONTINUE INTO THURSDAY NIGHT AT WHICH TIME SEAS WILL START RESPONDING TO THE INCREASED FLOW AND FETCH DURATION. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...MBB LONG TERM...MBB AVIATION...43
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
107 PM CST SUN DEC 1 2013 .UPDATE... ISSUED AT 107 PM CST SUN DEC 1 2013 CANCELLED DENSE FOG ADVISORY AS VISIBILITY HAS RISEN ABOVE 1/2 MILE AT ALL OBSERVATION SITES EXCEPT A COUPLE (VALLEY CITY/LANGDON). THERE STILL MAY BE A FEW SPOTS WITH DENSE FOG THROUGH THE AFTERNOON...BUT IT IS NO LONGER WIDESPREAD ENOUGH TO JUSTIFY AN ADVISORY. MOTORISTS SHOULD STILL BE PREPARED FOR RAPIDLY CHANGING DRIVING CONDITIONS...ESPECIALLY AROUND FAVORED LOW SPOTS FOR FOG FORMATION. LOW CLOUDS ARE REALLY TAKING A BITE OUT OF TEMPERATURES... SO DROPPED AFTERNOON HIGHS A HANDFUL OF DEGREES. BAND OF LIGHT SNOW HAS MOVED INTO AREAS WEST OF THE VALLEY AND THIS IS HANDLED WELL BY CURRENT POPS. REST OF THE FORECAST OK WITH NO OTHER CHANGES AT THIS TIME. UPDATE ISSUED AT 1015 AM CST SUN DEC 1 2013 CONCERNS THIS MORNING INCLUDE FOG AND LIGHT SNOW. DENSE FOG DEVELOPED ACROSS AREAS WEST OF THE VALLEY FROM LANGDON TO COOPERSTOWN TO GWINNER BETWEEN 7 AND 8 AM CST AND HAS MAINTAINED ITSELF FOR MUCH OF THE MORNING. LATEST RAP/HRRR GUIDANCE SUGGESTS POCKETS OF DENSE FOG WILL CONTINUE THROUGH LATE MORNING AND INTO THE AFTERNOON AND WITH NO REAL CHANGE IN AIR MASS AND/OR LOW LEVEL WIND FIELD...WILL ISSUE A DENSE FOG ADVISORY FOR WESTERN TIER COUNTIES UNTIL 21 UTC. MAY VERY WELL BE ABLE TO CANCEL IT EARLY...BUT VISIBILITIES AT OR BELOW 1/4 SM ARE WIDESPREAD ENOUGH TO WARRANT ISSUANCE. ALSO INCREASED POPS A BIT FARTHER EAST ACROSS EASTERN ND THROUGH THE DAY WITH A NARROW BAND OF LIGHT SNOW JUST ENTERING THE DEVILS LAKE BASIN. RAP SOUNDING AT KDVL SUGGESTS THERE MAY BE SOME FREEZING DRIZZLE MIXED IN...BUT UPSTREAM OBSERVATIONS THUS FAR HAVE BEEN ALL SNOW. PRIMARY MID-LEVEL WARM AIR ADVECTION SNOW STILL STRETCHES FROM KENMARE TO GARRISON AND WILL IMPACT THE REGION LATER THIS AFTERNOON AND EVENING. ALSO INTRODUCED SOME 20 POPS ACROSS THE LAKE OF THE WOODS REGION LATE THIS MORNING FOR SOME LIGHT SNOW BEING REPORTED AT ROSEAU...BAUDETTE AND WASKISH. TEMPERATURE/SKY/WIND GRIDS ARE IN GOOD SHAPE WITH NO MAJOR CHANGES AT THIS TIME. && .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 418 AM CST SUN DEC 1 2013 00Z/06Z MODELS ARE COMING MORE IN LINE TOWARD A GENERAL CONSENSUS SOLUTION...WITH THE GFS REMAINING A FAST OUTLIER. EVEN THE NAM IS SIMILAR TO THE CONSENSUS...JUST STRONGER. THE IDEA IS THAT AN UPPER LOW WILL DIG INTO THE NORTHWEST CONUS/NORTHERN ROCKIES...THEN EJECT INTO NORTHERN MINNESOTA BY 12Z WED. MODELS HAVE REMAINED CONSISTENT INDICATING 3 ROUNDS OF SNOWFALL. THE FIRST ROUND WILL BE LATER THIS AFTERNOON INTO TONIGHT. FORCING IS WEAK AND AVAILABLE MOISTURE IS RELATIVELY LOW...THINKING UP TO AN INCH OF SNOWFALL IS MOST LIKELY. THE SECOND WAVE (MONDAY INTO MONDAY NIGHT) IS STRONGER...WITH MORE AVAILABLE MOISTURE (PWATS APPROACHING 0.5 INCHES). MODELS INDICATE A DEFINED CIRCULATION AT 850MB (AND A WEAK 700MB LOW) PROPAGATING FROM NW ND INTO WESTERN MN ON MONDAY...LOSING DEFINITION MONDAY NIGHT AS IT PROPAGATES FURTHER TO THE EAST. ASSOCIATED WARM AIR ADVECTION/FRONTOGENESIS COMBINED WITH THE 0.5 INCH PWATS SHOULD LEAD TO A BAND OF SNOWFALL MOVING THROUGH THE REGION. MODELS INDICATE 0.20-0.40 INCHES QPF ACROSS ALL BUT THE NE FA...AND COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA OF 2-5 INCHES OF SNOW. MODELS INDICATE THAT THE MESOSCALE FORCING IS RELATIVELY WEAK...WHICH WOULD MEAN THE MODELS SHOULD BE IN THE BALL PARK WITH QPF. THE THIRD ROUND OF SNOWFALL (TUESDAY-TUESDAY NIGHT) WILL BE ASSOCIATED WITH THE MAIN STRONG MID-LEVEL LOW MOVING THROUGH THE REGION. THE 00Z ECMWF IS SLIGHTLY FASTER WITH THIS FEATURE. SYNOPTIC FORCING WILL BE VERY STRONG...WITH THE POTENTIAL FOR MESOSCALE BANDING. WITH THAT SAID...THIS ROUND OF SNOWFALL STILL HAS THE MOST UNCERTAINTY (DUE TO MODEL DIFFERENCES). GIVEN THE AVAILABLE MOISTURE (PWATS 0.5+ INCHES) AND STRONG FORCING EXPECTED...ALONG WITH THE SLOW MOVING NATURE OF THE SYSTEM...THIS ROUND SHOULD BRING 6+ INCHES (CURRENT THOUGHTS ARE 5 TO 10 INCHES) TO MOST AREAS. SOMETIME TOWARD THE TAIL END OF THE SNOWFALL...WINDS SHOULD INCREASE...LIKELY STRONG ENOUGH FOR BLOWING SNOW ISSUES. SINCE THE TRUE WINTER WARNING CONDITIONS WILL LIKELY NOT OCCUR UNTIL SOMETIME ON TUESDAY...WILL HOLD OFF ON ISSUING ANY WINTER HEADLINES. THIS WILL ALLOW FOR ANOTHER SET OF MODEL RUNS TO INCREASE CONFIDENCE. COULD SEE A SITUATION WHERE WE HAVE ADVISORY CONDITIONS ON MONDAY/MONDAY NIGHT FOLLOWED BY A SHORT BREAK...THEN WARNING CRITERIA SNOW TUESDAY/TUESDAY NIGHT (WITH WINDS AND BLOWING SNOW LATER TUESDAY NIGHT INTO WEDNESDAY). WILL ADD SOME DETAIL TO THE SPECIAL WEATHER STATEMENT AND HWO. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 418 AM CST SUN DEC 1 2013 WEDNESDAY-SATURDAY...BOTH THE GFS/ECMWF INDICATE SNOW WINDING DOWN ON WEDNESDAY AS THE SFC LOW PULLS AWAY. DESPITE A TREND TOWARDS A FASTER SOLUTION...THERE IS STILL SOME UNCERTAINTY WITH THE 00Z GEM SLOWER WITH THE SFC LOW...KEEPING SNOW AROUND THROUGH WEDNESDAY NIGHT. SOME LIGHT SNOW/SNOW SHOWERS COULD LINGER INTO LATE WEEK AS A REINFORCING UPPER LOW PIVOTS SOUTHWARD INTO THE REGION...MAINTAINING CYCLONIC FLOW. HOWEVER...THE MAIN CONCERN FOR THE REMAINDER OF THE WEEK WILL BE TEMPS AS A BITTERLY COLD ARCTIC AIR MASS TAKES UP RESIDENCE ACROSS THE NORTHERN PLAINS. BASED ON A MORE PROGRESSIVE SOLUTION...STRONG LOW-LEVEL COLD ADVECTION MAY PREVENT MUCH TEMPERATURE RISE ON WEDNESDAY. 1000-500 MB THICKNESSES FALL BELOW 500 DAM BY THURSDAY/FRIDAY...WITH HIGHS NO HIGHER THAN THE LOW SINGLE DIGITS. MODELS INDICATE THE SFC HIGH AXIS DOES NOT APPROACH UNTIL NEXT WEEKEND. THUS...WITH ONLY A GRADUAL SLACKENING OF THE PRESSURE GRADIENT...WINDS WILL REMAIN UP A BIT THROUGH THE WORK WEEK. THE COMBINATION OF WINDS AND BITTERLY COLD TEMPS LIKELY WILL LEAD TO DANGEROUS WIND CHILLS AT TIMES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 107 PM CST SUN DEC 1 2013 IFR AND LOWER CIGS WILL CONTINUE THROUGH THE EARLY AFTERNOON. SAT LOOP SHOWS SOME CLEARING ON THE BACK SIDE OF THE TROUGH AXIS IN WESTERN ND...BUT MODELS ALL HAVE THE SFC TROUGH STARTING TO WASH OUT...WITH THE WESTERLY WINDS NEVER REACHING OUR FORECAST AREA. THINK THAT THE STRATUS WILL CONTINUE THROUGH THE REST OF THE DAY...POSSIBLY LIFTING TO MVFR LEVELS FOR A BRIEF PERIOD. CONDITIONS WILL DETERIORATE AGAIN THIS EVENING AS CIGS DROP BACK DOWN BELOW 1000 FT AND A BAND OF LIGHT SNOW MOVES IN. THE SNOW WILL BE BRIEF AND ONLY AFFECT TAF SITES FOR A FEW HOURS WITH VIS AROUND 2SM OR SO. HOWEVER...AFTER THE SNOW MOVES OFF TO THE EAST THE LOW CIGS AND SOME MIST WILL CONTINUE. THERE WILL BE ANOTHER...HEAVIER BAND OF SNOW BEGINNING TO MOVE INTO THE FORECAST AREA LATE IN THE PERIOD. THE BAND COULD BE AS FAR EAST AS KFAR AND KGFK BY 18Z...BUT FOR NOW WILL JUST INCLUDE A MENTION AT KDVL. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...ROGERS SHORT TERM...TG LONG TERM...MAKOWSKI AVIATION...JR
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1015 AM CST SUN DEC 1 2013 .UPDATE... ISSUED AT 1015 AM CST SUN DEC 1 2013 CONCERNS THIS MORNING INCLUDE FOG AND LIGHT SNOW. DENSE FOG DEVELOPED ACROSS AREAS WEST OF THE VALLEY FROM LANGDON TO COOPERSTOWN TO GWINNER BETWEEN 7 AND 8 AM CST AND HAS MAINTAINED ITSELF FOR MUCH OF THE MORNING. LATEST RAP/HRRR GUIDANCE SUGGESTS POCKETS OF DENSE FOG WILL CONTINUE THROUGH LATE MORNING AND INTO THE AFTERNOON AND WITH NO REAL CHANGE IN AIR MASS AND/OR LOW LEVEL WIND FIELD...WILL ISSUE A DENSE FOG ADVISORY FOR WESTERN TIER COUNTIES UNTIL 21 UTC. MAY VERY WELL BE ABLE TO CANCEL IT EARLY...BUT VISIBILITIES AT OR BELOW 1/4 SM ARE WIDESPREAD ENOUGH TO WARRANT ISSUANCE. ALSO INCREASED POPS A BIT FARTHER EAST ACROSS EASTERN ND THROUGH THE DAY WITH A NARROW BAND OF LIGHT SNOW JUST ENTERING THE DEVILS LAKE BASIN. RAP SOUNDING AT KDVL SUGGESTS THERE MAY BE SOME FREEZING DRIZZLE MIXED IN...BUT UPSTREAM OBSERVATIONS THUS FAR HAVE BEEN ALL SNOW. PRIMARY MID-LEVEL WARM AIR ADVECTION SNOW STILL STRETCHES FROM KENMARE TO GARRISON AND WILL IMPACT THE REGION LATER THIS AFTERNOON AND EVENING. ALSO INTRODUCED SOME 20 POPS ACROSS THE LAKE OF THE WOODS REGION LATE THIS MORNING FOR SOME LIGHT SNOW BEING REPORTED AT ROSEAU...BAUDETTE AND WASKISH. TEMPERATURE/SKY/WIND GRIDS ARE IN GOOD SHAPE WITH NO MAJOR CHANGES AT THIS TIME. && .SHORT TERM...(TODAY THROUGH TUESDAY NIGHT) ISSUED AT 418 AM CST SUN DEC 1 2013 00Z/06Z MODELS ARE COMING MORE IN LINE TOWARD A GENERAL CONSENSUS SOLUTION...WITH THE GFS REMAINING A FAST OUTLIER. EVEN THE NAM IS SIMILAR TO THE CONSENSUS...JUST STRONGER. THE IDEA IS THAT AN UPPER LOW WILL DIG INTO THE NORTHWEST CONUS/NORTHERN ROCKIES...THEN EJECT INTO NORTHERN MINNESOTA BY 12Z WED. MODELS HAVE REMAINED CONSISTENT INDICATING 3 ROUNDS OF SNOWFALL. THE FIRST ROUND WILL BE LATER THIS AFTERNOON INTO TONIGHT. FORCING IS WEAK AND AVAILABLE MOISTURE IS RELATIVELY LOW...THINKING UP TO AN INCH OF SNOWFALL IS MOST LIKELY. THE SECOND WAVE (MONDAY INTO MONDAY NIGHT) IS STRONGER...WITH MORE AVAILABLE MOISTURE (PWATS APPROACHING 0.5 INCHES). MODELS INDICATE A DEFINED CIRCULATION AT 850MB (AND A WEAK 700MB LOW) PROPAGATING FROM NW ND INTO WESTERN MN ON MONDAY...LOSING DEFINITION MONDAY NIGHT AS IT PROPAGATES FURTHER TO THE EAST. ASSOCIATED WARM AIR ADVECTION/FRONTOGENESIS COMBINED WITH THE 0.5 INCH PWATS SHOULD LEAD TO A BAND OF SNOWFALL MOVING THROUGH THE REGION. MODELS INDICATE 0.20-0.40 INCHES QPF ACROSS ALL BUT THE NE FA...AND COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA OF 2-5 INCHES OF SNOW. MODELS INDICATE THAT THE MESOSCALE FORCING IS RELATIVELY WEAK...WHICH WOULD MEAN THE MODELS SHOULD BE IN THE BALL PARK WITH QPF. THE THIRD ROUND OF SNOWFALL (TUESDAY-TUESDAY NIGHT) WILL BE ASSOCIATED WITH THE MAIN STRONG MID-LEVEL LOW MOVING THROUGH THE REGION. THE 00Z ECMWF IS SLIGHTLY FASTER WITH THIS FEATURE. SYNOPTIC FORCING WILL BE VERY STRONG...WITH THE POTENTIAL FOR MESOSCALE BANDING. WITH THAT SAID...THIS ROUND OF SNOWFALL STILL HAS THE MOST UNCERTAINTY (DUE TO MODEL DIFFERENCES). GIVEN THE AVAILABLE MOISTURE (PWATS 0.5+ INCHES) AND STRONG FORCING EXPECTED...ALONG WITH THE SLOW MOVING NATURE OF THE SYSTEM...THIS ROUND SHOULD BRING 6+ INCHES (CURRENT THOUGHTS ARE 5 TO 10 INCHES) TO MOST AREAS. SOMETIME TOWARD THE TAIL END OF THE SNOWFALL...WINDS SHOULD INCREASE...LIKELY STRONG ENOUGH FOR BLOWING SNOW ISSUES. SINCE THE TRUE WINTER WARNING CONDITIONS WILL LIKELY NOT OCCUR UNTIL SOMETIME ON TUESDAY...WILL HOLD OFF ON ISSUING ANY WINTER HEADLINES. THIS WILL ALLOW FOR ANOTHER SET OF MODEL RUNS TO INCREASE CONFIDENCE. COULD SEE A SITUATION WHERE WE HAVE ADVISORY CONDITIONS ON MONDAY/MONDAY NIGHT FOLLOWED BY A SHORT BREAK...THEN WARNING CRITERIA SNOW TUESDAY/TUESDAY NIGHT (WITH WINDS AND BLOWING SNOW LATER TUESDAY NIGHT INTO WEDNESDAY). WILL ADD SOME DETAIL TO THE SPECIAL WEATHER STATEMENT AND HWO. .LONG TERM...(WEDNESDAY THROUGH SATURDAY) ISSUED AT 418 AM CST SUN DEC 1 2013 WEDNESDAY-SATURDAY...BOTH THE GFS/ECMWF INDICATE SNOW WINDING DOWN ON WEDNESDAY AS THE SFC LOW PULLS AWAY. DESPITE A TREND TOWARDS A FASTER SOLUTION...THERE IS STILL SOME UNCERTAINTY WITH THE 00Z GEM SLOWER WITH THE SFC LOW...KEEPING SNOW AROUND THROUGH WEDNESDAY NIGHT. SOME LIGHT SNOW/SNOW SHOWERS COULD LINGER INTO LATE WEEK AS A REINFORCING UPPER LOW PIVOTS SOUTHWARD INTO THE REGION...MAINTAINING CYCLONIC FLOW. HOWEVER...THE MAIN CONCERN FOR THE REMAINDER OF THE WEEK WILL BE TEMPS AS A BITTERLY COLD ARCTIC AIR MASS TAKES UP RESIDENCE ACROSS THE NORTHERN PLAINS. BASED ON A MORE PROGRESSIVE SOLUTION...STRONG LOW-LEVEL COLD ADVECTION MAY PREVENT MUCH TEMPERATURE RISE ON WEDNESDAY. 1000-500 MB THICKNESSES FALL BELOW 500 DAM BY THURSDAY/FRIDAY...WITH HIGHS NO HIGHER THAN THE LOW SINGLE DIGITS. MODELS INDICATE THE SFC HIGH AXIS DOES NOT APPROACH UNTIL NEXT WEEKEND. THUS...WITH ONLY A GRADUAL SLACKENING OF THE PRESSURE GRADIENT...WINDS WILL REMAIN UP A BIT THROUGH THE WORK WEEK. THE COMBINATION OF WINDS AND BITTERLY COLD TEMPS LIKELY WILL LEAD TO DANGEROUS WIND CHILLS AT TIMES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 650 AM CST SUN DEC 1 2013 IFR CONDITIONS WILL LIKELY CONTINUE THROUGH THE MORNING HOURS...GRADUALLY RISING WITH DAYTIME HEATING (BUT NOT GREATER THAN MVFR CRITERIA). 10Z RAP GUIDANCE SHOWS THE POTENTIAL FOR A PERIOD OF VFR CONDITIONS TONIGHT AS LOW LEVEL FLOW INCREASES. THIS SEEMS LIKE A LOW PROBABILITY OF OCCURRENCE CONSIDERING THAT THE LOW-LEVEL AIRMASS IS EXPECTED TO REMAIN SATURATED. WILL MONITOR THE SITUATION AND ADJUST THE FORECASTS AS NEEDED. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR NDZ006-007- 014-015-024-026-028-038-049-052. MN...NONE. && $$ UPDATE...ROGERS SHORT TERM...TG LONG TERM...MAKOWSKI AVIATION...TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
419 PM EST SUN DEC 1 2013 .SYNOPSIS... A WEAK COLD FRONT WILL MOVE INTO THE AREA TONIGHT...STALLING AND DISSIPATING LATE ON MONDAY. INCREASING SOUTHERLY FLOW WILL ALLOW FOR WARMING TEMPERATURES AND GRADUAL INCREASES FOR PRECIPITATION CHANCES...BEFORE A STRONGER COLD FRONT MOVES THROUGH THE AREA LATE IN THE WEEK. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... A WEAK FRONTAL BOUNDARY...EVIDENT MOST READILY WHEN LOOKING AT SURFACE WINDS...IS CURRENTLY MOVING SOUTHWARD INTO OHIO. THERE IS INCREASING LOW-LEVEL RH BEHIND THIS BOUNDARY...WITH A DRY AREA CURRENTLY EXTENDING ACROSS MOST OF NORTHERN AND WESTERN OHIO AHEAD OF IT. MEANWHILE...AN AREA OF THICK STRATOCUMULUS HAS BEEN VERY GRADUALLY MOVING EAST ACROSS OHIO AND KENTUCKY TODAY. TIMING OUT THE MOTIONS OF THESE DIFFERING RH LAYERS HAS BEEN A CHALLENGE...WITH SEVERAL SCENARIOS IN THE MODELS AND WHAT SEEMS TO BE A SLIGHT OVEREMPHASIS ON HIGHER RH VALUES. THE SLOW MOTION OF THE CLOUDS COMING IN FROM THE NORTH LENDS ITSELF TO A PARTLY- CLOUDY-AT-WORST FORECAST FOR MOST OF THE CWA (AT LEAST EARLY IN THE OVERNIGHT...AND CERTAINLY NOT INCLUDING THE SOUTHEAST). HOWEVER...CONFIDENCE DOES INCREASE THAT CLOUDS AND LOW-LEVEL RH (PERHAPS VERY LOW) WILL BE IN PLACE BY MORNING. NAM AND RAP BUFKIT SOUNDINGS SHOWED THE THICK MOISTURE CONFINED TO THE LOWEST 1000 FEET...THOUGH THE GFS APPEARED TOO AGGRESSIVE IN SATURATING EVERYTHING UNDER 5KFT. THERE WAS EVEN SOME CONSIDERATION TO INCLUDING DRIZZLE IN THE FORECAST...BUT LIFT IS NOT STRONG AND THE SOUTHWARD EXTENT OF THE RH IS CERTAINLY IN QUESTION. DESPITE THE EXPECTED CLOUDS...MIN TEMPS (ESPECIALLY IN THE NORTH) SHOULD AGAIN COOL TO VALUES NEAR OR SLIGHTLY BELOW FREEZING...WITH MID TO UPPER 30S ELSEWHERE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... ALTHOUGH NO SIGNIFICANT IMPACTS ARE EXPECTED DURING THE SHORT TERM OF THE FORECAST...AND POPS ARE EXPECTED TO REMAIN IN THE CHANCE RANGE OR LOWER...THE SPECIFIC DETAILS FOR PRECIPITATION AND CLOUDS (IN TERMS OF AMOUNTS AND TIMING) ARE A LITTLE LOWER IN CONFIDENCE THAN NORMAL. THE BOUNDARY FORECAST TO MOVE INTO THE FORECAST AREA TONIGHT AND INTO EARLY MONDAY MORNING WILL LOSE ITS DEFINITION...LEAVING THE CWA IN A PATTERN OF VERY WEAK S-TO-SE FLOW. FLOW IN THE MID LEVELS WILL BE QUASI-ZONAL...BUT WITH A SOMEWHAT-BROAD SHORTWAVE MOVING INTO THE OHIO VALLEY ON MONDAY. THE OVERALL RESPONSE TO THIS FEATURE IS NOT ESPECIALLY STRONG ON ALL MODELS BUT THE GFS (EVEN ON BOTH THE 06Z AND 12Z RUNS). ALTHOUGH LOW LEVEL MOISTURE APPEARS PREVALENT ON MOST MODELS...THE GFS IS BY FAR THE MOST ENHANCED WITH DEEPER MOISTURE AND QPF RESPONSE. POPS FOR MONDAY AND INTO MONDAY NIGHT HAVE BEEN SCALED BACK TO SLIGHT CHANCE...PUSHING NORTH OF THE CWA BEFORE TUESDAY MORNING BEGINS. AFTER WHAT LOOKS TO BE A DRY PERIOD ON TUESDAY...WARM FRONTAL PROCESSES WILL BEGIN...AS LOW PRESSURE DEVELOPS OVER THE MISSISSIPPI VALLEY. THIS WILL INCREASE THE SOUTHERLY FLOW AND BEGIN A PATTERN OF WARM ADVECTION THAT WILL CONTINUE INTO THE LONG TERM OF THE FORECAST. INCREASING CONVERGENCE AND MOISTURE TRANSPORT (ESPECIALLY ALOFT ON TUESDAY NIGHT) WILL RESULT IN PRECIPITATION CHANCES GRADUALLY INCREASING FROM WEST TO EAST ACROSS THE CWA...THOUGH MOTION OF SHOWERS WILL BE IN MORE OF A SSW-TO-NNE DIRECTION. THIS IS ONE PART OF THE FORECAST THAT DOES COME WITH A BIT OF INCREASING CONFIDENCE. BECAUSE OF THIS...TEMPERATURE ADJUSTMENTS WERE ALSO REQUIRED FOR BOTH TUESDAY (SLIGHTLY UPWARD) AND TUESDAY NIGHT (SIGNIFICANTLY UPWARD). PLENTIFUL CLOUDS AND MOISTURE...COMBINED REASONABLY STRONG FLOW FOR AN OVERNIGHT PERIOD...SUPPORTS THIS DECISION. THE CURRENT GRIDS WERE INCREASED BY 5-7 DEGREES...BUT IF SOME OF THE RAW MODELS ARE TO BE BELIEVED...THIS MAY NOT EVEN BE ENOUGH. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... UPPER LEVEL PATTERN WILL TRANSITION TO A HIGHLY AMPLIFIED REGIME THROUGH THE EXTENDED PERIOD. THERE CONTINUES TO BE ISSUES WITH TIMING AND RUN TO RUN CONTINUITY WITH MAJOR SYNOPTIC SYSTEMS TO AFFECT OUR REGION. LOOKING AT THE VARIOUS OPERATIONAL MODELS...HAVE DECIDED TO GO WITH A 25 PERCENT 12Z ECMWF AND A 75 PERCENT 12Z GFS. WE ARE GETTING TO THE POINT IN THE FORECAST WHERE DIURNAL RISE AND FALL WILL NOT CUT IT WITH FRONTS MOVING THROUGH AND WAVES OF LOW PRESSURE RIDING ALONG THE FRONTAL BOUNDARY. ON WEDNESDAY...LONG WAVE TROUGH WILL BE CARVING ITSELF OUT OVER THE WESTERN U.S. FIRST WEATHER ISSUE IS THE AMOUNT OF ENERGY THAT WILL EJECT FROM THIS FEATURE ACROSS THE NORTHERN PLAINS AND INTO CENTRAL CANADA. GFS IS STRONGER AND FASTER WITH THIS ENERGY WHILE THE ECMWF IS SLOWER...AND THIS HAS BEEN THE CASE OVER THE LAST SVRL RUNS. THIS WILL HAVE FRONTAL IMPLICATIONS THROUGH OUR REGION WEDNESDAY INTO THURSDAY. WITH AFOREMENTIONED BLEND...IT ALLOWS FOR A COLD FRONT TO MOVE THROUGH THE REGION WEDNESDAY NIGHT...BUT NOT AS FAST AS THE GFS INDICATES. IN ADVANCE OF THE FRONT...WAA SHOWERS ARE FORECAST TO BREAK OUT AND LIKELY POPS SEEM REASONABLE AT THIS TIME. FOR THE PERIOD THURSDAY INTO FRIDAY...THIS TIME FRAME IS SHAPING UP TO BE INCLEMENT AS COLD FRONT SAGS TO OUR SOUTHEAST AND BECOMES QUASI STATIONARY AS WAVES OF LOW PRESSURE RIDE ALONG IT. THESE WAVES WILL BRING A SHOT OF FRONTOGENETIC FORCING TO OUR REGION LATE THURSDAY INTO THURSDAY NIGHT WITH ANOTHER ROUND OF MID TO UPR LVL FORCING FRIDAY INTO FRIDAY NIGHT. DURING THIS TIME...COLD AIR WILL SLOWLY SEEP INTO THE REGION FROM THE NORTHWEST. AS SUCH...THERE WILL BE SOME WINTRY PCPN TYPE ISSUES AS LOW LEVELS COOL BUT AIR ABOVE WILL BE SLOWER TO COOL. STILL TO EARLY TO GET SPECIFIC GIVEN THE THERMAL FIELD OSCILLATIONS AT THIS POINT SO JUST HAVE RAIN/SNOW MENTIONED. LIKELY POPS STILL SEEM REASONABLE FOR MOST OF THE REGION WITH EACH WAVE RIPPLING BY. BY FRIDAY NIGHT INTO SATURDAY...COLD ARCTIC HIGH PRESSURE WILL WEDGE SOUTHEAST INTO OUR AREA. THIS SHOULD PUSH THE PCPN OUT OF THE AREA BY SATURDAY. THE HIGH WILL SET UP ACROSS THE REGION SATURDAY NIGHT AND WILL MOVE EAST BY SUNDAY. THIS SHOULD GIVE THE REGION A DRY BUT COLD PERIOD OF WEATHER. && .AVIATION /21Z SUNDAY THROUGH FRIDAY/... A WEAK COLD FRONT/WIND SHIFT WILL DISSIPATE OVER THE OHIO VALLEY OVERNIGHT TONIGHT AS IT PROGRESSES SOUTHEAST. CLOUD COVER ASSOCIATED WITH THIS FRONT WILL PRIMARILY BE AN AS DECK. BEFORE THIS OCCURS...SC OVER AND SOUTHEAST OF I-71 CORRIDOR WILL SLOWLY ERODE FROM W-E THIS AFTERNOON. ABUNDANT MOISTURE SHOULD ALLOW SC TO RE-DEVELOP THIS EVENING AND OVERNIGHT ONCE THE LOWER LEVELS STRATIFY. SOME MVFR VSBYS ARE EXPECTED AND WILL BECOME MORE LIKELY OVERNIGHT IF THE LOWER STRATUS IS A BIT MORE CUMULUS WITH WIDER BREAKS. DISSIPATED FRONT OVER THE REGION WILL LEAD TO CONTINUED LOW AND MID LEVEL MOISTURE WITH LIGHT AND SOMETIMES VARIABLE WINDS. OUTLOOK...MVFR CEILINGS POSSIBLE THROUGH TUESDAY MORNING. IFR CEILINGS AND MVFR VISIBILITIES WILL BE POSSIBLE LATE MONDAY NIGHT. MVFR CEILINGS AND VISIBILITIES POSSIBLE AGAIN WEDNESDAY INTO THURSDAY. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...HICKMAN AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS PORTLAND OR
245 PM PST SUN DEC 1 2013 .SYNOPSIS... A STRONG COLD FRONT TONIGHT TO BRINGS A PERIOD OF RAIN TO THE PACIFIC NW...WITH RAIN TURNING TO SNOW IN THE CASCADES THROUGH THE NIGHT AN UPPER LEVEL TROUGH SINKING S OVER THE REGION WILL KEEP A THREAT FOR SHOWERS GOING THROUGH MON WITH SNOW LEVELS IN THE FOOTHILLS BY AFTERNOON. A CONTINENTAL COLD FRONT WILL FOLLOW TUE...BRINGING EVEN COLDER BUT DRIER THAT WILL REMAIN THROUGH THE REST OF THE WEEK. && .SHORT TERM...SUNDAY THROUGH TUESDAY NIGHT...FOR THE REST OF TODAY EXPECT WINDS TO INCREASE IN MOST LOCATIONS. WE HAD A FEW GUSTS IN OUR COAST RANGE RAWS REACH 60 MPH...AND WHILE CERTAINLY NOT REPRESENTATIVE OF MOST COAST RANGE LOCATIONS...IT IS WINDY. AHEAD OF THE COLD FRONT THIS EVENING THESE ELEVATIONS 1500-2000 FEET WILL EASILY DO THIS AGAIN AS HAS STARTED TO OCCUR. LATEST GUIDANCE STILL KEEPS WINDS UNDER HIGH WIND LEVELS ALONG THE COAST...BUT SOME EXPOSED SPOTS MAY STILL SEE 50 MPH. LATEST HRRR ALSO KEEPS VALLEY GUSTS LIMITED TO ABOUT 40 MPH BUT HIGHER EXPOSED HILLS WILL LIKELY DO A LITTLE BETTER AS THERE IS A VERY STRONG 925 MB WIND FIELD. PEAK WINDS LOOK TO BE LATE THIS AFTERNOON AND EARLY EVENING. TRYING TO HONE IN EXACTLY HOW MUCH SNOW WILL FALL AT THE PASSES IS PROVING TO BE A CHALLENGE. WHILE OUR SNOW ADVISORY CRITERIA IS 6" IN 12 HR...THIS MAY NOT QUITE HAPPEN AT THE PASSES BUT HIGHER ELEVATIONS SHOULD EASILY BE ABLE TO DO THIS. MODELS APPEAR FAIRLY CONSISTENT IN SHOWING THE CHANGEOVER TO SNOW AT PASS LEVEL NOT COMING UNTIL LATE TONIGHT INTO MON MORNING...AFTER THE DEEPER MOISTURE AND HEAVIER PRECIPITATION HAVE MOVED S...BUT AGREE WITH EARLIER SHIFTS REASONING THAT SHOWERS CONTINUE ALL DAY MONDAY AS THE SHARP UPPER TROUGH SWINGS THROUGH IN MOIST OROGRAPHIC FLOW. A SNOW ADVISORY HAS THEREFORE BEEN ISSUED THE NORTH OREGON AND LANE COUNTY CASCADES TO TAKE INTO ACCOUNT ADDITIONAL ACCUMULATIONS WITH THE INITIAL ONSET OF MODERATE TO HEAVY SNOW WHEN THE CHANGEOVER OCCURS. PLUS THERE WILL BE QUITE A BIT OF BLOWING AND DRIFTING OF SNOW IN EXPOSED LOCATIONS. THE HIGHEST IMPACT PERIOD WILL BE LATE TONIGHT AND TOMORROW MORNING WHEN THE TRANSITION OCCURS...BUT WILL RUN THE ADVISORY THROUGH LATE AFTERNOON/EARLY EVENING TO ACCOUNT FOR CONTINUED SNOW SHOWERS. DID NOT DO AN ELEVATION BASED HAZARD AS THEY WILL BE FALLING THROUGH THE PERIOD AND DID NOT WANT TO SEND A MIXED MESSAGE...BUT MORE SIGNIFICANT SNOW WILL BE AT 4000 FEET AND ABOVE. SNOW LEVELS WILL GET INTO THE COAST RANGE AND FOOTHILL ELEVATIONS THOUGH GENERALLY LIGHT ACCUMULATIONS IN SHOWERS WILL BE EXPECTED. SPOTS ABOVE 1500-2000 FEET MAY SNEAK OUT 3 INCHES IN HEAVIER SHOWERS. FOR THOSE HOPING FOR MORE THAN A FEW FLAKES AT THE LOWEST ELEVATIONS MONDAY NIGHT...IT DOES NOT LOOK TOO PROMISING AS WE REMAIN IN SOUTHERLY FLOW IN THE VALLEY BEFORE THE AIR MASS DRIES AND COOLS ENOUGH. THE AIR MASS IS COLD ENOUGH OVERNIGHT FOR AT LEAST A MIX OF RAIN AND SNOW SHOWERS BEFORE THINGS WIND DOWN. THE INTERESTING DEVELOPMENT IS FOR TUESDAY NIGHT AS THE SECOND ROUND OF COLD AIR FILTERS IN AND A STRONGER BAROCLINIC ZONE SETS UP BETWEEN THE MILD OCEAN AND THE COLD CONTINENTAL AIR. BOTH THE NAM/SREF DEPICT SOME WEAK LIFT MOVING THROUGH. NORTHERLY UPSLOPE FLOW THROUGH THE VALLEY MAY BE ABLE TO WRING OUT SOME LIGHT SNOW TOWARD EUGENE...BUT THE SREF IS THE ONLY MODEL SHOWING ENOUGH MOISTURE FOR ANYTHING MORE THAN SOME FLURRIES...AND EVEN ITS QPF FIELD WILL ONLY RESULT IN A LIGHT DUSTING IN ANY SHOWERS. MODELS PAINT SLIGHTLY BETTER MOISTURE IN THE CASCADES WITH THIS WAVE SO NOTHING TO WRITE HOME ABOUT FOR NOW. TUESDAYS HIGHS STRUGGLE TO MAKE 40 AND LOOK TO BE THE WARMEST HIGHS OF THE WEEK. /KMD .LONG TERM...WEDNESDAY THROUGH SATURDAY...WE LOOK TO GET A SECOND SURGE OF COLDER AIR BEGINNING WEDNESDAY. THE COLDEST GFS ENSEMBLES AND ECMWF MOS GUIDANCE GIVES VALLEY HIGHS IN THE LOW TO MID 30S...WITH LOWS IN THE MID TO UPPER TEENS TO AROUND 20 FOR WEDNESDAY WITH BOTH MODELS AGREEING ON THE COLDEST DAY BEING THURSDAY. UNCERTAINTY IN THE FORECAST FROM A PRECIPITATION PERSPECTIVE GETS MUCH HIGHER FOR FRIDAY AND BEYOND AS THE GFS BRINGS ANOTHER SURGE OF COLD AIR BEFORE A MODERATION IN THE AIR MASS SLOWLY OCCURS THROUGH THE WEEKEND. MEANWHILE THE ECMWF WHICH HAD AN OVERRUNNING LIGHT SNOW ACROSS THE REGION ON FRIDAY FROM ITS 12Z RUN YESTERDAY...THEN THE SAME SCENARIO WAS PUSHED BACK TO FRIDAY NIGHT INTO EARLY SATURDAY ON THE 00Z RUN TODAY...AND NOW THE 12Z RUN SHOWS SOMETHING SIMILIAR TO THESE RUNS BEFORE BRING ANOTHER SHOT OF COLD AIR LATER IN THE WEEKEND. THE MODELS DO AGREE ON A HIGHLY AMPLIFIED FLOW PATTERN WITH A LARGE BLOCKING RIDGE OFFSHORE WITH NORTHERLY FLOW OVER THE NW. WHERE THE DIFFERENCES COME IN IS THAT THERE IS LOW FURTHER OFFSHORE THAT THE EURO MODEL ATTEMPTS TO SEND MOISTURE UP OVER THE RIDGE INTO ALASKA THAN BACK DOWN OVER OUR AREA. MEANWHILE THE GFS DOES HAVE A LOW MOVING THROUGH BUT IT IS NOT NEARLY AS SHARP AND THE NORTHWARD MOVING MOISTURE IS UNABLE TO SURVIVE THE RETURN TRIP SOUTH. WILL HOLD OFF ON ANY LARGE SCALE CHANGES AND KEEP THE LOW POP MENTION IN FOR FRIDAY...BUT THE TEMPERATURE THEME REMAINS THE SAME...AND EXTENDED PERIOD OF VERY COLD CONDITIONS. /KMD && .AVIATION...LITTLE CHANGE IN CIGS AND VSBY TODAY IN WARM SECTOR OF APPROACHING FRONT. EXPECT MVFR CIGS INLAND TO HOLD AROUND 2000 FT MSL WITH IFR PERSISTING ALONG THE COAST. WINDY. SURFACE WINDS SOUTHWESTERLY WITH GUSTS TO 50 KT AT THE COAST...AND GUSTS 35 TO 40 KT POSSIBLE INLAND. WINDS ALOFT AT 4000-5000 FT MSL ARE WESTERLY AROUND 40 KT THIS MORNING...EXPECTED TO INCREASE UP TO 60 KT THIS AFTERNOON. KPDX AND APPROACHES...MVFR IN RAIN TODAY. LITTLE CHANGE IN CIGS THIS AFTERNOON. CIGS LOOK TO RAPIDLY DECREASE AFTER 22Z AS FRONT MOVES IN...FOR IFR CIGS NEAR 500-800 FT POSSIBLE 22Z-04Z. SOUTHERLY WINDS WITH GUSTS TO 35 KT. BURGESS && .MARINE...FEW UPDATES. PREVIOUS DISCUSSION FOLLOWS. SOUTHERLY WINDS 20-25 KT WILL PERSIST THIS MORNING AS A WARM FRONT MOVES ACROSS THE NORTHERN WATERS. STRONGER WINDS WILL MOVE NORTH TO SOUTH THROUGH THE WATERS TODAY AND MONDAY WITH A POTENT COLD FRONT. HAVE UPGRADED THE GALE WATCH TO A WARNING FOR THIS EVENING INTO EARLY MONDAY SINCE MODELS CONTINUE TO SHOW GUSTS NEAR 35 KT. BREEZY NW WINDS CONTINUE INTO MONDAY NIGHT BEFORE BUILDING HIGH PRESSURE INLAND BRINGS A RETURN OF NE WINDS TUESDAY AFTERNOON. A LONG PERIOD SWELL REMAINS IN THE WATERS EARLY THIS MORNING. BUOYS CURRENTLY SHOW TWO WESTERLY SWELL TRAINS ONE AT 16 SECONDS...AND ONE AT 11 SECONDS. SINCE THESE SWELLS WOULD BE DIFFICULT TO DISTINGUISH HAVE LEFT THEM COMBINED FOR THE FORECAST. THE LONGER PERIOD SWELL WILL BECOME DOMINANT THIS AFTERNOON. HOWEVER THE PERIODS WILL DROP RAPIDLY WITH STEEP (SQUARE) SEAS LIKELY TONIGHT. THE GALE WARNING TAKES THESE STEEP SEAS INTO ACCOUNT...WITH OVERALL SEAS PEAKING AROUND 15 FEET LATE TONIGHT. THE SEAS WILL SUBSIDE BELOW 10 FEET LATE TUESDAY EVENING. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 PM PST THIS AFTERNOON FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM. GALE WARNING FROM 4 PM THIS AFTERNOON TO 7 AM PST MONDAY FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM. SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 7 AM PST MONDAY. && $$ MORE WEATHER INFORMATION ONLINE AT... HTTP://WEATHER.GOV/PORTLAND INTERACT WITH US VIA SOCIAL MEDIA WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV WWW.TWITTER.COM/NWSPORTLAND THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
304 PM CST SUN DEC 1 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 304 PM CST SUN DEC 1 2013 MAIN CONCERN THE NEXT 24 H IS THE SMALL POTENTIAL FOR PRECIPITATION...PRIMARILY OVER SOUTHWEST MINNESOTA. ALL MODELS SHOW TWO WAVES MOVING ACROSS THE DAKOTAS AND MINNESOTA THE NEXT 24 H. THE FIRST WAVE IS ALREADY INTO CENTRAL SD PER WATER VAPOR IMAGERY AND WILL LIKELY BE INTO SW MN AND NW IA BY 00Z. THERE ARE FEW ECHOES ASSOCIATED WITH THIS SYSTEM AND THOSE ARE PRIMARILY ACROSS FAR NORTHERN SOUTH DAKOTA. WITH VERY DRY AIR BELOW 10000 FT AND BEST FORCING FOR ASCENT IN NRN SD...HAVE REMOVED ANY CHC OF PRECIPITATION WITH THIS WAVE. CLOSE ON ITS HEELS THOUGH IS A SECOND WAVE. THE NAM IS FASTER AND FARTHER NORTH THAN EITHER THE RAP OR GFS WITH THIS WAVE. CURRENT TRAJECTORY FROM WATER VAPOR FAVORS THE GFS AND RAP AND FOLLOWED FOR LATER TONIGHT. THIS PUTS SAME STRONG PRESSURE ADVECTION ON THE 1.5 PV SFC OVER THE CWA BY MIDNIGHT AND CONTINUING THROUGH SUNRISE. AGAIN...MOISTURE IS A BIG ISSUE AS ALL MODELS SHOW A 5000 TO 10000 FT DRY LAYER ABOVE THE SURFACE. FOR MUCH OF SE SD AND NW IA...THIS DRY AIR EXPECTED TO EVAPORATE ANY PRECIPITATION THAT DOES REACH THE SURFACE. THE ONLY PLACE THE DRY AIR MAY BE OVERCOME IS IN SW MN WHERE IT MAY INTERACT WITH THE 850 MB BOUNDARY AND ENHANCE THE LIFT AND SATURATION. WHILE THE DRY AIR LIKELY WILL LIMIT PCPN EVEN THERE...DID KEEP A SLIGHT CHANCE OF PRECIPITATION FROM LATE EVENING THROUGH 12Z IN SW MN. TEMPERATURES ALOFT ARE WELL ABOVE FREEZING...EVEN THE WET BULB TEMPERATURE WILL BE ABOVE ZERO AND SHOULD MELT ANY PRECIPITATION ALOFT. TEMPERATURES AT THE SURFACE THIS EVENING EXPECTED TO DROP TO AROUND 30 AND THEN STEADY OUT AS CLOUDS AND SOUTH WINDS INCREASE. WHILE THERE IS A POSSIBILITY TEMPERATURES COULD RISE ABOVE FREEZING AS ANY PRECIPITATION MOVES IN...BELIEVE IT IS MOST LIKELY TO STAY JUST BELOW FREEZING MOST OF THE NIGHT. SO ANY PRECIPITATION WILL LIKELY BE A MIX OF FREEZING RAIN AND SLEET. AMOUNTS WILL BE LIGHT...A TRACE TO A COUPLE HUNDREDTHS...BUT ENOUGH THAT IT COULD SLICK UP ROADS SHOULD IT FALL. OTHERWISE...THE PRECIPITATION WILL MOVE OFF BY MONDAY MORNING. THERE WILL BE A LOT OF CLOUDS AROUND...ESPECIALLY EAST OF THE JAMES RIVER. IT WILL ALSO BE VERY WARM ALOFT WITH +10C AT 925 MB IN SOUTH CENTRAL SD WHERE THERE WILL ALSO BE SOME SUN. THEREFORE...EXPECT HIGHS TO WARM INTO THE LOWER TO MID 50S IN SOUTH CENTRAL SD...WITH UPPER 40S POSSIBLE OVER MUCH OF SE SD AND INTO NORTHEAST NEBRASKA AND NORTHWEST IOWA. THE COLDEST TEMPS WILL BE IN SW MN WHERE CLOUDS WILL BE AROUND MOST OF THE DAY AND WINDS WILL REMAIN S OR SE. BUT EVEN THERE HIGHS WILL REACH THE LOWER 40S. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 304 PM CST SUN DEC 1 2013 THERE SEEMS TO BE LITTLE SUPPORT FOR PRECIPITATION MONDAY NIGHT AHEAD OF THE APPROACHING LOW AND COLD FRONT. WITH SOME MID LEVEL MOISTURE LIKELY TO BE PRESENT...HAVE GONE WITH JUST A SLIGHT CHANCE OF LIGHT RAIN/FREEZING RAIN FOR LATE MONDAY NIGHT...THAT IS AFTER MIDNIGHT/06Z. THIS IDEA CONTINUES INTO TUESDAY AS THE LOW AND FRONT MOVES INTO THE AREA. THE GFS...EC...AND GEM/CANADIAN ARE FAIRLY CLOSE TO EACH OTHER ON THE PATH AND MOVEMENT OF THE LOW/FRONT AS IT ENTERS THE AREA AND ARE ACCEPTED OVER THE NAM...WHICH SEEMS TO BE TOO FAST AND TOO FAR NORTH. EITHER WAY...ANY STEADY OR WIDESPREAD PRECIPITATION SHOULD STAY NORTH OF THE AREA...AND AM GOING FOR ONLY A CHANCE OF LIGHT PRECIPITATION...WITH THE CHANCE INCREASING SLOWLY FROM THE NORTHWEST IN THE INCOMING COLD AIR. AHEAD OF THE COLD AIR THE SLIGHT PRECIPITATION THREAT WILL BE LIGHT RAIN/SNOW OR JUST LIGHT RAIN...AND OF COURSE AS THE COLD AIR ARRIVES THE CHANCE WILL BE FOR JUST LIGHT SNOW. THIS COOLING SHOULD BE COMPLETE BY EARLY TUESDAY EVENING...AGAIN SHOWER THAN THE NAM WOULD SUGGEST. TEMPERATURES...QUITE MILD MONDAY NIGHT...WILL RISE JUST A LITTLE FAR NORTHWEST...TO A FEW DEGREES SOUTHEAST...BEFORE THE COLDER AIR TURNS THEM STEADY THEN FALLING. EVEN BY THE SLOWER GFS AND EC...THE COLD INVASION WILL BECOME WELL ESTABLISHED BY TUESDAY EVENING. WILL CONTINUE THE CHANCES OF LIGHT SNOW THROUGH WEDNESDAY AND OF A FEW FLURRIES INTO THURSDAY. LACK OF SUPPORT DOOMS ACCUMULATIONS...IF ANY...TO BE QUITE LIGHT. FRIDAY AND SATURDAY LOOK DRY AND COLD. THE COLD AIR WILL BE QUITE BITING WITH WIND CHILLS CURRENTLY EXPECTED TO PI TO BELOW ZERO FAR WEST BY WEDNESDAY MORNING. BY THURSDAY MORNING THE WHOLE AREA SHOULD BE BELOW ZERO AND THE NORTH PERHAPS GETTING CLOSE TO THE ADVISORY BOUNDARY OF 20 BELOW ZERO. TEMPERATURES AND WIND CHILLS WILL BE PARTLY DEPENDENT ON WHETHER OR NOT WE GET ANY SNOW COVER...EVEN A HALF INCH TO INCH WILL HAVE AN EFFECT. WHAT WE WILL HAVE IN THE FORECAST COULD BE A LITTLE COLDER OR LESS COLD DEPENDING ON THAT FACTOR. AMD GOING WITH THE EXTENDED GUIDANCE INDICATING A LOW CHANCE OF SNOW FOR DAY 7...NEXT SUNDAY. THE EC IS THE ONLY MODEL INDICATING ANYTHING...BUT AS FAR WEST AS IT KEEPS THE UPPER TROUGH...GOING BY IT ALONE WOULD RATE A BIGGER THREAT...SO SLIGHT CHANCE SEEMS THE BEST ROAD FOR NOW. THERE WILL BE SOME SLIGHT MODERATION IN THE COLD TEMPERATURES...BUT ONLY SLIGHT AS THE COLD REGIME WILL DOMINATE FOR A WHILE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1110 AM CST SUN DEC 1 2013 WINDS WILL REMAIN LIGHT THROUGH THE PERIOD...WITH A GRADUALLY SHIFT TO SOUTH TOMORROW MORNING ALONG AND WEST OF I29. VFR CONDITIONS EXPECTED AND NO PCPN EXPECT AT KHON...KFSD...AND KSUX. AT THIS POINT...IF THERE IS ANY PCPN...MAY BE A SPRINKLE OR FLURRY OVERNIGHT IN SW MN BUT VSBYS WOULD REMAIN ABOVE 6SM AND CIGS ABOVE 3000 FT. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...SCHUMACHER LONG TERM... AVIATION...SCHUMACHER
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
307 PM CST SUN DEC 1 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 307 PM CST SUN DEC 1 2013 CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS SHOWED A POTENT UPPER TROUGH DROPPING DOWN THROUGH WESTERN BRITISH COLUMBIA...WITH NEARLY ZONAL FLOW DOWNSTREAM ACROSS THE NORTHERN U.S.. WITHIN THIS ZONAL FLOW...THERE ARE SOME WEAK SHORTWAVES...ONE OVER SOUTHEAST BRITISH COLUMBIA AND A SECOND IN THE DAKOTAS. DPVA AND WARM ADVECTION AHEAD OF THIS SECOND SHORTWAVE HAS BEEN SPREADING MID/HIGH CLOUDS DOWNSTREAM INTO THE FORECAST AREA. SO FAR THE ONLY SPOT PRECIPITATION HAS BEEN FALLING OUT OF THESE CLOUDS HAS BEEN ACROSS CENTRAL NORTH DAKOTA. COMPARING THE 12Z BIS AND MPX SOUNDINGS...MUCH MORE MOISTURE EXISTED ACROSS NORTH DAKOTA... RELATIVELY SPEAKING AS PRECIPITABLE WATER AMOUNTS ARE ONLY 0.13 INCHES DIFFERENT. FARTHER EAST...HIGH PRESSURE HAS BUILT INTO THE FORECAST AREA AT THE SURFACE BEHIND LAST NIGHTS COLD FRONT. THE STRATUS THAT WAS COMING IN AHEAD OF THE HIGH PRESSURE AREA HAS STALLED MOSTLY NORTH OF HWY 29 IN WI. 925MB TEMPS ARE ABOUT 3C COOLER TODAY AND AS RESULT...THE SUN HAS ONLY ALLOWED THE TEMPERATURES TO CLIMB INTO THE 30S. MODELS ARE ALL IN GOOD AGREEMENT DIVING THE POTENT UPPER TROUGH OVER WESTERN BRITISH COLUMBIA DIGGING INTO THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THIS IN TURN SENDS THE SHORTWAVE IN SOUTHERN BRITISH COLUMBIA EASTWARD...CROSSING THE FORECAST AREA MONDAY AFTERNOON. PRIOR TO THIS SHORTWAVE...WE FIRST MUST DEAL WITH THE SHORTWAVE IN THE DAKOTAS WHICH IS PROGGED TO COME ACROSS THE AREA THIS EVENING. IT APPEARS ALL THE SHORTWAVE WILL BRING IS CONTINUED MID/HIGH CLOUDS AS THE LOW LEVELS REMAIN DRY AS SHOWN NICELY IN THE 12Z MPX SOUNDING. NOW OVERNIGHT...INCREASING 280-295K ISENTROPIC LIFT OVER THE DAKOTAS AHEAD OF THE APPROACHING BRITISH COLUMBIA SHORTWAVE WILL LIKELY DEVELOP PRECIPITATION FROM THE DAKOTAS INTO CENTRAL MINNESOTA. MODELS HAVE SLOWED DOWN THE PRECIPITATION SPREAD SOUTHEAST INTO THE FORECAST AREA PRIOR TO 12Z...WHICH SEEMS REASONABLE AND HAVE DELAYED THE PRECIPITATION CHANCES TO LATE IN THE NIGHT. THE BETTER CHANCES FOR PRECIPITATION COME DURING THE DAY MONDAY AS THE SHORTWAVE CROSSES THE FORECAST AREA...PROVIDING DPVA AND A SPREAD SOUTHEASTWARD OF THE 280-295K ISENTROPIC LIFT INTO THE FORECAST AREA. STILL...THERE ARE DIFFERENCES WITH THE MAIN PRECIP AXIS. THE 01.12Z CANADIAN...01.00Z/01.12Z ECMWF SUGGEST AN ALIGNMENT FROM CENTRAL MN INTO NORTHEAST IA/FAR SOUTHWEST WI...THE 01.12Z NAM PLACES IT MOSTLY NORTH OF I-94...AND THE 01.12Z GFS IS SORT OF A SPLIT BETWEEN THE TWO. WITH NO CLEAR SIGNAL ON WHICH MODEL GROUP MIGHT VERIFY...HAVE FOLLOWED A COMPROMISE. THIS COMPROMISE RESULTS IN LOW CHANCES...20-40...BECAUSE OF THE VARIABILITY OF LOCATION. FUTURE SHIFTS SHOULD BE ABLE TO RAISE CHANCES AND HONE IN ON AN ALIGNMENT OF THE PRECIP AXIS. WITH 925MB AND 850MB TEMPS PROGGED AT OR BELOW 0C ACROSS MUCH OF THE FORECAST AREA AND EVAPORATIVE COOLING LIKELY TO TAKE PLACE WHERE IT DOES PRECIPITATE...THINKING THAT THE PRECIPITATION WILL MAINLY FALL IN THE FORM OF SNOW. THERE MAY BE SOME MIXING WITH RAIN POSSIBLE IN THE AFTERNOON IF TEMPERATURES WARM INTO THE MID TO POSSIBLY UPPER 30S AS EXPECTED. NO MODEL IS THAT HEAVY ON QPF...MOSTLY ON THE ORDER OF A TENTH...MAYBE TWO TENTHS AT MOST. WITH SNOW TO WATER RATIOS LIKELY IN THE 10-15 TO 1 RANGE AND DURING THE DAY WHEN THE SUN CAN HAVE SOME IMPACT ON LIMITING ACCUMULATIONS...THINKING MOSTLY UP TO 1 INCH OF SNOWFALL. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 307 PM CST SUN DEC 1 2013 MAIN LONG TERM FORECAST CONCERNS ARE PRECIPITATION CHANCES AND TEMPERATURES THROUGH WEDNESDAY...THEN TEMPERATURES BEYOND THAT AS ARCTIC AIR BEGINS TO FLOW IN. THE BIGGEST ISSUE TO THE FORECAST IS THE EVOLUTION OF THE TROUGHING THAT DROPS INTO THE PACIFIC NORTHWEST AND NORTHERN ROCKIES ON MONDAY. GOOD MODEL CONSENSUS EXISTS THAT THE WESTERN PART OF THE TROUGH IS GOING TO DIG DEEPLY THROUGH THE WESTERN U.S.. THE EASTERN PART OF THE TROUGH...ON THE OTHER HAND...DIFFERENCES SHOW UP WHICH HAVE HUGE IMPLICATIONS TO THE FORECAST. THE 01.12Z NAM HAS THE EASTERN PORTION OF THE TROUGH MOVING INTO THE DAKOTAS ON TUESDAY AS A CLOSED LOW...WHEREAS THE 01.12Z GFS/ECMWF/CANADIAN STILL HOLD IT BACK IN SOUTHWEST MONTANA. THUS...THE NAM EXITS PRECIP THE QUICKEST COME WEDNESDAY AND BEGINS THE FLOW OF ARCTIC AIR IN THE EARLIEST. BASED ON AVAILABLE MODEL GUIDANCE...HAVE MOSTLY DISCOUNTED THE NAM AS AN OUTLIER. OF THE 01.12Z GFS/ECMWF/CANADIAN...THE GFS BECOMES THE NEXT FASTEST OF EXITING THE PRECIPITATION AND BRINGING THE COLD AIR ON WEDNESDAY...RESULTING FROM MOVING THE UPPER LOW OUT TO THE EAST QUICKER. HARD TO SAY WHICH OF THIS MODEL GROUP IS CORRECT. HOWEVER...ITS WORTH NOTING THAT THE ECMWF/CANADIAN HAVE SPED UP FROM YESTERDAY...REGARDING THE UPPER LOW...EXITING THE PRECIPITATION AND BRINGING IN THE COLD AIR. THUS...THE FORECAST FOR MONDAY NIGHT THROUGH WEDNESDAY TAKES A BLEND OF THE GFS/ECMWF/CANADIAN AND CONTINUITY. FOR MUCH OF MONDAY NIGHT THROUGH TUESDAY NIGHT...THE FORECAST AREA REMAINS IN THAT 280-295K ISENTROPIC LIFT ZONE LEFTOVER FROM MONDAY. THE STRONGEST OF THE LIFT OVERALL STAYS CENTERED NORTH OF I-90. PRECIPITATION CHANCES INCREASE BECAUSE MOISTURE CONTINUES TO INCREASE AND DEEPEN. PRECIPITABLE WATER INCREASES FROM NEAR 0.5 INCH ON MONDAY TO 0.6-0.7 INCHES ON TUESDAY. WARMER AIR FLOWING IN ON SOUTH TO SOUTHEAST 925-850MB WINDS SHOULD ALLOW PRECIPITATION THAT IS A SNOW OR RAIN/SNOW MIX MONDAY NIGHT INTO TUESDAY MORNING TO SWITCH MOSTLY OVER TO ALL RAIN BY TUESDAY AFTERNOON. THE ONE EXCEPTION TO THIS IS OVER TAYLOR COUNTY WHICH IS FARTHEST FROM THE WARMER AIR ADVECTING IN FROM THE SOUTH. WEDNESDAY IS VERY TRICKY WITH TEMPERATURES AND PRECIPITATION CHANCES...AS IT HIGHLY DEPENDS ON THE TIMING OF THE UPPER LOW AND AN EXPECTED COLD FRONTAL PASSAGE. TEMPERATURES COULD EITHER BE IN THE MID 30S - LOW 40S OR MID 20S - LOW 30S...WHICH OF COURSE GREATLY AFFECTS PRECIPITATION TYPE. AS MENTIONED EARLIER...STUCK WITH A COMPROMISE. SINCE THE LIFT OVERALL IS WEAK FOR MUCH OF THE MONDAY NIGHT THROUGH WEDNESDAY TIME PERIOD...MUCH OF THE PRECIPITATION SHOULD BE ON THE LIGHT SIDE. TAYLOR COUNTY AGAIN AS THE GREATEST SHOT OF SEEING SNOW...BUT WITH THE LIGHT ASPECT TO THE PRECIPITATION AND LOWER SNOW TO WATER RATIOS...ACCUMULATIONS SHOULD STAY LESS THAN 1 INCH IN EACH 6 HOUR PERIOD. NOW IF YOU TOTAL THIS UP...SNOWFALL AMOUNTS BY WEDNESDAY EVENING END UP IN THE 4-6 INCH RANGE...BUT SETTLING...AND POSSIBLY MIXING WITH RAIN ON TUESDAY AFTERNOON... PUTS A LOT OF DOUBT FOR NEED OF AN ADVISORY AT THIS TIME. AFTER WEDNESDAY...ITS ALL ABOUT THE ARCTIC AIR AS A LONGWAVE TROUGH SETS UP FROM THE SOUTHWESTERN U.S. INTO NORTHERN ONTARIO. THE MAIN REASON FOR ARCTIC AIR COMING IS A POLAR STREAM UPPER TROUGH THAT DROPS SOUTH OUT OF CENTRAL CANADA AND PROGRESSES ACROSS THE UPPER MIDWEST ON FRIDAY. AS THIS POLAR TROUGH APPROACHES...850MB/925MB TEMPS JUST GRADUALLY DROP RIGHT THROUGH FRIDAY. BY 00Z SATURDAY...850MB STANDARDIZED ANOMALIES ARE DOWN TO -2.5. IF WE CAN GET SOME SNOW ON WEDNESDAY...EVEN 1 INCH TO STAY ON THE GROUND...TEMPERATURES COULD BE QUITE A BIT COLDER THAN FORECAST FOR THURSDAY THROUGH SATURDAY. DOES NOT LOOK LIKE ANY REAL MEASURABLE SNOW THREAT UNTIL SUNDAY AT THE EARLIEST...AND THATS IF THE ECMWF IS CORRECT IN TIMING OF BRINGING OUT A STRONGER WAVE OUT OF THE WESTERN TROUGH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1146 AM CST SUN DEC 1 2013 AS WEAK WARM AIR ADVECTION DEVELOPS ACROSS THE AREA THIS AFTERNOON A BROKEN 8-10K FOOT DECK OF CLOUDS WILL SPREAD ACROSS THE AREA. THESE CLOUDS HAVE ALREADY MOVED INTO KRST AND WILL MOVE INTO KLSE AROUND 01.21Z. THESE CLOUDS WILL GRADUALLY DROP INTO THE 4 TO 8K RANGE OVERNIGHT...AND THEN KRST WILL SEE A BKN015 DECK DEVELOP AROUND 02.16Z. WITH THE MODELS CONTINUING TO STRUGGLE ON WHERE THE PRECIPITATION WILL OCCUR...DID NOT INCLUDE THEM IN EITHER TAF SITE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...AJ LONG TERM...AJ AVIATION...BOYNE
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND MONDAY ISSUED AT 220 PM CST SUN DEC 1 2013 SEVERAL FORECAST ISSUES THIS PERIOD INCLUDING SOUTHERN EXTENT OF LOW CLOUDS OVERNIGHT...WHETHER LAKE EFFECT SNOW SHOWERS AFFECT DOOR COUNTY...AND TIMING OF NEXT SYNOPTIC-SCALE SYSTEM. WEAK LOW-LEVEL WAA TONIGHT AS WINDS BECOME SW-W. AS A RESULT WOULD EXPECT THE LOW CLOUDS TO STICK AROUND OVER MUCH OF THE AREA. DIURNAL CU THAT FORMED ALONG SOUTHERN EXTENT OF LOW CLOUDS MAY DISSIPATE BUT HIGHER CLOUDS UPSTREAM MOVING IN. REPEATED RUNS OF HRRR AND OTHER SHORT-TERM MODELS INDICATE SOME LAKE EFFECT SNOW SHOWERS ASSOCIATED WITH POSSIBLE MESOVORTEX OVER NORTH-CENTRAL LK MICHIGAN TONIGHT WHICH COULD CLIP DOOR COUNTY. DELTA-T`S ARE MARGINAL BUT WILL CONTINUE WITH SMALL CHANCE OF SNOW SHOWERS OR FLURRIES IN NORTHERN DOOR. MIN TEMPS SHOULD DROP INTO THE 20S MOST AREAS AWAY FROM LK MICHIGAN. ON MONDAY...WAA INCREASES AS NEXT SYSTEM APPROACHES FROM THE WEST. SOME LIGHT SNOW OR FLURRIES EXPECTED TO MOVE INTO AT LEAST THE WESTERN HALF OF THE AREA BY LATE AFTERNOON. STILL SOME QUESTION AS TO HOW FAST SYSTEM BEGINS TO AFFECT AREA...SO WILL CONTINUE TO USE MODEL BLEND WHICH RESULTS IN TIMING SIMILAR TO PREVIOUS FORECAST. HIGH TEMP FORECAST A BLEND OF BEST PERFORMING MOS GUIDANCE WHICH IS NOT FAR OFF FROM PREVIOUS FORECAST. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 220 PM CST SUN DEC 1 2013 A VERY CHALLENGING FORECAST PERIOD THROUGH MID WEEK DUE TO TIMING ISSUES WITH A DEVELOPING STORM SYSTEM AND PCPN TYPE. THE POTENTIAL EXISTS FOR WINTER HEADLINES OVER NORTH CENTRAL WISCONSIN FOR MAINLY SNOW. STARTING MONDAY NIGHT...NAM AND GFS CONTINUE TO REMAIN A BIT QUICKER WITH SPREADING THE BAND OF SNOW OVER THE AREA FASTER WITH THE WARM AIR ADVECTION. OLD ECMWF IS ABOUT 12 HOURS SLOWER WHILE THE GEM WAS THE AVERAGE. LATEST ECMWF IS CLOSER TO THE GEM TIME WITH THE INITIAL WAA TOWARD MONDAY NIGHT. AVAILABLE FORECAST SOUNDINGS DO INDICATE SNOW AT THE START FOR THE PCPN TYPE WITH AROUND AN INCH OR TWO OF ACCUMULATION BY TUESDAY MORNING...WITH THE 2 INCH AMOUNTS TOWARD CENTRAL AND NORTH CENTRAL AND POINTS NORTHWEST. THE AIR COLUMN LIKELY WILL REMAIN COLD ENOUGH FOR SNOW FOR ANOTHER 2 INCHES ACROSS THE NORTH. ITS POSSIBLE AN ADVISORY WILL BE NEEDED FOR NORTH CENTRAL AND PARTS OF FAR NORTHEAST WISCONSIN FOR THIS INITIAL BAND. SNOW AMOUNTS APPEAR TO DIMINISH DUE TO CONTINUED WAA AND PCPN CHANGING TO RAIN OR A RAIN SNOW MIX. THE NAM FORECAST SOUNDING FOR RHI CHANGES THE SN OVER BRIEFLY ZR THEN RAIN TUESDAY NIGHT THEN BACK TO SNOW LATE. WITH FROST DEPTHS A FEW INCHES DEEP OVER MANY LOCATIONS DUE TO THE COLD LATER HALF OF NOVEMBER...POTENTIAL OF BRIEF PERIOD ICY ROADS DUE TO ZR AND COLD GROUND. NOT CONFIDENT OF THE ZR AT THIS TIME BUT IF THIS BECOMES MORE OF A THREAT...WINTER WEATHER ADVISORIES MAY BE NEEDED FOR THAT ELEMENT ALONE TOWARD TUESDAY AS WELL. BLEND OF MEDIUM RANGE MODELS WITH THE H850 LOW TRACKS SUGGESTS THE SYSTEM PCPN/SNOW TO REMAIN NORTHWEST OF THE AREA BUT CLOSE ENOUGH TO PRODUCE ANOTHER INCH OR TWO OVER NORTH CENTRAL WISCONSIN. AT THIS TIME...UP TO 6 INCHES OF SNOW POSSIBLE OVER PARTS OF NORTH CENTRAL WISCONSIN FROM MONDAY NIGHT INTO WEDNESDAY MORNING. BUT DUE TO THE SNOW AMOUNTS WILL BE SPREAD OVER A 36-48 PERIOD...NO WATCH ISSUED AT THIS TIME. ANTICIPATE A LONG DURATION ADVISORY OR TWO SHORTER WINTER ADVISORIES MAY BE NEEDED TO HANDLE THE SNOW ACCUMULATION AND OR MIX CLOSER TO THE EVENT. BITTERLY COLD ARCTIC AIR WILL THEN POUR INTO THE ARE IN THE WAKE OF THE SYSTEM. WITH NEED TO HAVE A HEALTHY NORTH TO SOUTH GRADIENT IN TEMPS LATER IN THE WEEK DUE TO THE COLDER TEMPERATURES OVER THE ANTICIPATED SNOW COVER OVER NORTH CENTRAL WISCONSIN TO PROBABLY LITTLE OR NO SNOW OVER CENTRAL AND EAST CENTRAL WISCONSIN. WINDS APPEAR TO WESTERLY FOR SIGNIFICANT LAKE EFFECT SNOWS TO REACH FAR NORTH CENTRAL WISCONSIN DURING THE ARTIC SURGE. MEDIUM RANGE RUNS BEGIN TO DEVELOP RETURN FLOW PCPN AGAIN LATE NEXT WEEKEND AND FOR THE START OF THE NEXT WEEK...WILL KEEP THE FORECAST DRY THROUGH NEXT WEEKEND FOR NOW. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1206 PM CST SUN DEC 1 2013 MVFR CIGS ACROSS MUCH OF FORECAST AREA DURING PERIOD. ISOLATED IFR CIGS NOTED IN VILAS COUNTY FROM TIME TO TIME. GENERALLY MVFR CIGS EXPECTED BEFORE MUCH LOWER CIGS AND VSBYS ARRIVE LATE MONDAY AND EARLY TUESDAY ASSOCIATED WITH NEXT STORM SYSTEM. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....JKL LONG TERM......TDH AVIATION.......JKL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 AM CST SUN DEC 1 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM CST SUN DEC 1 2013 THE MAIN FOCUS IS ON THE INCREASING CHANCES FOR SNOW TONIGHT...MAINLY IN SOUTHEAST MINNESOTA...NORTHEAST IOWA AND FAR WESTERN WISCONSIN. CURRENTLY...NORTHWESTERLY FLOW ALOFT IS IN PLACE WITH A SURFACE RIDGE OF HIGH PRESSURE CENTERED ON THE EASTERN DAKOTAS. THE INITIAL QUESTION THIS MORNING IS WITH A STRATUS DECK THAT EXTENDS ACROSS NORTHERN WISCONSIN/MINNESOTA AND HOW FAR SOUTH IT WILL MAKE IT TODAY. THERE HAS NOT BEEN MUCH OF A SOUTHERLY PUSH WITH IT OVER THE PAST 6 HOURS OR SO...EXCEPT IN EASTERN WISCONSIN ALONG LAKE MICHIGAN. THE PAST FEW RUNS OF THE HRRR SHOW THIS STRATUS DECK HAVING TROUBLE MAKING IT SOUTH TODAY AS THE RIDGE OF HIGH PRESSURE COMES IN AND WEAKENS THE NORTHERLY SURFACE FLOW. IF THIS DECK DOES MAKE IT FURTHER SOUTH...IT WILL CAUSE TEMPERATURES TO BE ABOUT 5-10F COOLER FOR HIGHS. GOING INTO TONIGHT...A LEAD/WEAK MID LEVEL SHORT WAVE TROUGH WILL PROPAGATE EAST ACROSS THE NORTHERN PLAINS WHILE ISENTROPIC LIFT ON THE 290K SURFACE INCREASES. THIS SHOULD PROVIDE ENOUGH LIFT...ALBEIT WEAK...TO DEVELOP A BAND OF LIGHT SNOW FROM CENTRAL MINNESOTA DOWN ALONG THE MISSISSIPPI RIVER. ANY ACCUMULATIONS OVERNIGHT WILL BE ON THE LIGHT SIDE AT A FEW TENTHS OF AN INCH OR LESS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 335 AM CST SUN DEC 1 2013 LIFT AND MOISTURE WILL BECOME DEEPER MONDAY INTO WEDNESDAY AS THE CORE OF THE MID LEVEL TROUGH APPROACHES THE REGION. FOR MONDAY...THE MAIN FOCUS CONTINUES TO BE ALONG THE NOSE OF THE LOW LEVEL WARM AIR ADVECTION AND WHERE IT WILL SET UP. ALL OF THE 01.00Z GUIDANCE SHOW THE BAND OF PRECIPITATION EXPANDING THROUGH THE DAY AS THIS ADVECTION STRENGTHENS. HOWEVER...AS WARMER AIR COMES IN AT THE LOW LEVELS...SOME PRECIPITATION TYPE ISSUES ARISE WITH THE WARM LAYER POSSIBLY CAUSING THE SNOW TO CHANGE OVER TO RAIN. SURFACE TEMPERATURES SHOULD ALSO BE ON THE RISE ABOVE FREEZING...SO AM NOT EXPECTING ANY FREEZING RAIN AT THE MOMENT. THERE IS SOME UNCERTAINTY TOO WITH THE POSITION OF THE NORTHWEST TO SOUTHEAST SWATH OF PRECIPITATION WITH THE 01.00Z NAM/01.03Z SREF BEING THE FARTHEST NORTHEAST WHILE THE 01.00Z GFS/ECMWF DEVELOP IS MORE TO THE SOUTHWEST IN SOUTHEAST MINNESOTA/NORTHEAST IOWA. MAY BE UNDER-DOING THE SNOW AMOUNTS ON MONDAY...BUT THE POTENTIAL MIX HAS ME CAUTIOUS TO GO MUCH ABOVE A FEW TENTHS OF AN INCH. THE BIGGEST STORY WITH THE 01.00Z GUIDANCE IS HOW THEY HAVE ALL COME AROUND TO THIS THINKING OF A MUCH FASTER FRONTAL PASSAGE WITH THE DEEPENING SURFACE LOW/MID LEVEL TROUGH MOVING THROUGH EARLY ON WEDNESDAY. THE BEST CHANCES FOR ANY PRECIPITATION APPEARS TO BE FROM MONDAY NIGHT THROUGH WEDNESDAY AS THIS TROUGH APPROACHES. THE WARMER AIR COMING IN ON TUESDAY AHEAD OF THE SYSTEM SHOULD KEEP THE P-TYPE MAINLY AS RAIN UNTIL THE COLD FRONT COMES THROUGH EARLY ON WEDNESDAY. THE MAIN CHANCES FOR SNOW WILL BE ON MONDAY NIGHT AHEAD OF THE WARM AIR..AND THEN AGAIN ON WEDNESDAY MORNING BETWEEN THE LEAD COLD FRONT PASSAGE AND THE SECONDARY COLD FRONT WHICH USHERS IN THE DRASTICALLY COLDER AIR IN. OVERALL...CONFIDENCE IN GETTING ANY SPECIFIC DETAILS DOWN ON THE PRECIPITATION TRENDS IS PRETTY LOW...PARTICULARLY WITH THE SNOW AMOUNTS. IF ANY SNOW IS ABLE TO OCCUR WEDNESDAY MORNING AFTER THE FIRST FRONT COMES THROUGH...IT WILL MEAN THAT TEMPERATURES COULD BE COLDER THAN ADVERTISED GOING THROUGH THE REST OF THE WEEK. DUE TO THE FASTER FROPA...HAVE DROPPED THE PRECIPITATION CHANCES FROM THURSDAY INTO THE WEEKEND. AS FOR THE COLD SPELL...850MB TEMPERATURES ARE FORECAST TO DROP DOWN TO BETWEEN -15 TO -20C ON THURSDAY WITH THE POOL OF COLD AIR LASTING THROUGHOUT THE REGION PAST NEXT WEEKEND. EVEN IF THERE IS NO SNOW COVER DOWN ON THE GROUND...TEMPERATURES WILL BE MUCH BELOW NORMAL THROUGH THE FORESEEABLE FUTURE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1146 AM CST SUN DEC 1 2013 AS WEAK WARM AIR ADVECTION DEVELOPS ACROSS THE AREA THIS AFTERNOON A BROKEN 8-10K FOOT DECK OF CLOUDS WILL SPREAD ACROSS THE AREA. THESE CLOUDS HAVE ALREADY MOVED INTO KRST AND WILL MOVE INTO KLSE AROUND 01.21Z. THESE CLOUDS WILL GRADUALLY DROP INTO THE 4 TO 8K RANGE OVERNIGHT...AND THEN KRST WILL SEE A BKN015 DECK DEVELOP AROUND 02.16Z. WITH THE MODELS CONTINUING TO STRUGGLE ON WHERE THE PRECIPITATION WILL OCCUR...DID NOT INCLUDE THEM IN EITHER TAF SITE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...HALBACH LONG TERM....HALBACH AVIATION...BOYNE
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1101 AM CST SUN DEC 1 2013 .UPDATE... CLOUDS OVER THE LAKE ARE GRADUALLY SWINGING WESTWARD ONTO THE SHORELINE. RAP AND NAM 1000-850MB WIND DIRECTION AND RH DEPICT THIS WELL. AT THIS TIME...THE CLOUDS APPEAR TO BE MIXING OUT A LITTLE OVER LAND. EXPECTING THE CLOUDS TO PUSH A LITTLE FURTHER INLAND LATER THIS AFTERNOON AS FLOW TURNS NNE. TEMPERATURES ARE A LITTLE TRICKY TODAY. THEY ARE ALREADY CLOSE TO REACHING THE FCST MAX TEMP...BUT 925MB TEMPS WILL REMAIN STEADY AROUND -3C TODAY. THEREFORE...WILL LEAVE MAX TEMPS ALONE...IN THE UPPER 30S. && .AVIATION/18Z TAFS/... LAKE CLOUDS ARE STARTING TO SHIFT WESTWARD ONTO THE SOUTHEAST WI SHORELINE. CIGS ARE 1400-2500 FEET. EXPECT THESE TO AFFECT MKE...RAC AND ENW THROUGH MUCH OF THE AFTERNOON. FLOW IS EXPECTED TO SHIFT NORTHEAST THEN EAST TONIGHT SO STRATUS FROM NORTHERN WI AND OVER THE LAKE ARE EXPECTED TO SPREAD INTO SOUTHEAST WI AND POSSIBLY SOUTH CENTRAL WI TONIGHT. UNCERTAINTY ABOUT CLOUD BASES...BUT PLANNING ON VFR INLAND AND MVFR NEAR THE SHORELINE FOR NOW. && .PREV DISCUSSION... /ISSUED 330 AM CST SUN DEC 1 2013/ TODAY AND TONIGHT...FORECAST CONFIDENCE MEDIUM TO HIGH NAM BRINGS STRATUS FIELD OVER EAST CENTRAL WI SWD THROUGH ERN WI AND OVER LAKE MI THROUGH THE MORNING. ONCE ESTABLISHED IT WILL LIKELY BE DIFFICULT TO ERODE ESPECIALLY NEAR LAKE MI DUE TO THE DEVELOPING INSTABILITY OVER LAKE MI. THE INSTABILITY OVER THE LAKE WILL CONTRIBUTE TO CLOUDS BUT NOT ENOUGH FOR PCPN. OVER SOUTH CENTRAL WI...WILL BE EXPECTING A PARTLY CLOUDY AND NICE DAY...HOWEVER THE WESTERN EXTENT OF THE EXPECTED STRATUS IS UNCERTAIN. HIGH PRESSURE CURRENTLY MOVING INTO MN WILL ARRIVE BY THIS EVENING. MIDDLE TO HIGH CLOUDS TO THEN INCREASE TONIGHT AS A SHORTWAVE TROUGH APPROACHES FROM THE WEST. NO PCPN IS EXPECTED UNTIL MONDAY OR MONDAY NIGHT. TEMPS NEAR NORMAL TODAY AND ABOVE NORMAL FOR TNT GIVEN EXPECTED CLOUDS. MONDAY - CONFIDENCE...MEDIUM SUBSIDING INFLUENCE OF HIGH DRIFTS EAST WITH DEVELOPING WAA. WEAK WAVE IN THE FLOW STILL GENERATED LIGHT QPF ON THE 12Z ECMWF IN THE FAR SE. HOWEVER 00Z RUN HAS DRIED IT OUT CONVERTING WI DURING THE MORNING SO WILL RETAIN SOME SMALL POPS FOR THIS. HOWEVER GFS AND NAM BOTH DRY AND ECMWF APPEARS TO BE A LITTLE LESS IMPRESSIVE WITH THIS. STILL WORTH A MENTION NONETHELESS. DURING THE AFTERNOON THE 00Z NAM AND 00Z GFS SHOW A PRONOUNCED UPSWING IN ISENTROPIC LIFT INTO SRN WI...ESP SC WI. THE ECMWF IS SLOWER ON ERODING THE LOW LEVEL THERMAL TROUGH AND SHOWS ALL QPF TIED TO THIS LIFT ACROSS IA AND MN. THE GFS IS THE COMPROMISE APPROACH KEEPING THE BETTER POTENTIAL ACROSS THE WESTERN CWA. MONDAY NIGHT - CONFIDENCE...LOW TO MEDIUM WARM AIR ADVECTION CONTINUES THIS PERIOD. THE 00Z NAM AND 00Z GFS ARE MORE AGGRESSIVE WITH LIFTING THE WARMER TEMPERATURES NORTH. MEANWHILE THE 12Z ECMWF SUGGESTS A SLOWER ARRIVAL OF THE WAA PRECIP WITH THE COLDER PROFILE LINGERING LONGER. THE 00Z HAS WARMED UP SOME BUT NOT AS MUCH AS THE NAM AND GFS SUGGEST. TUESDAY - CONFIDENCE...MEDIUM 00Z NAM AND 00Z GFS BOTH SHOW WARM CONVEYOR WELL ENTRENCHED AHEAD OF THE PLAINS LOW. 12Z ECMWF SHOWED A SLOWER SOLUTION WITH 850 TEMPS 5-8 DEGREES COLDER AND STILL IMPLYING A LINGERING MIX POTENTIAL WHILE GFS AND NAM CLEARLY FAVOR ALL RAIN. THE NEW 00Z ECMWF HAS WARMED CONSIDERABLY CONVERGING ON THE NAM AND GFS SOLUTION. SO WILL TREND ANY MIX OVER TO RAIN FOR THE AFTERNOON. WEDNESDAY AND WEDNESDAY NIGHT - CONFIDENCE...LOW WHILE THE 00Z ECMWF HAS TRENDED FASTER ON THE FRONTAL TIMING...THE GFS STILL REMAINS MUCH QUICKER WITH COLD ADVECTION WELL UNDERWAY. THE ECMWF AND NAM SHOW THE MILD AIR LINGERING AT LEAST THROUGH THE MORNING BEFORE THE FRONT ARRIVES TOWARDS MIDDAY. SO HIGHS MAY END UP BEING IN THE MORNING PRIOR TO FRONTAL PASSAGE. HOWEVER IF THE TREND OF THE ECMWF PLAYING CATCHUP TO THE GFS CONTINUES...THEN THE DAY COULD END UP STARTING ON THE CHILLY SIDE. FOR NOW WILL LEAN TO THE WARM WEDGE AT LEAST HAVING A SAY FOR A PART OF THE DAY. 00Z ECMWF DOES SHOW SOME LIGHT SNOW POTENTIAL WEDNESDAY NIGHT WITH SECONDARY FEATURE WITH AN UPTICK IN 700-300 MILLIBAR Q-VECTOR CONVERGENCE SO WILL RETAIN A SMALL CHANCE OF -SN FOR WEDNESDAY NIGHT. THURSDAY THROUGH SATURDAY - CONFIDENCE...MEDIUM STEADY COLD ADVECTION FOR THIS PERIOD. COLDEST AIR ARRIVES SATURDAY WITH 925 TEMPS -15 TO -20C. MOST OF THE CWA LOOKS TRAPPED IN THE TEENS FOR HIGHS ON SATURDAY. AVIATION/12Z TAFS/...STRATUS FIELD WITH CIGS OF 1.0-3.0 KFT CONTINUES TO MOVE STEADILY SWD FROM NE WI INTO EAST CENTRAL WI. THE NAM DOES BRING THE STRATUS FIELD INTO EAST CENTRAL AND SE WI FOR TODAY AND TNT AND FOLLOWED THIS SCENARIO. LESS UNCERTAINTY OVER SOUTH CENTRAL WI SINCE STRATUS HAS HALTED OVER CENTRAL AND NW WI AND MODELS INDICATE A MUCH LOWER POTENTIAL OF STRATUS THERE. WILL GO WITH FEW-SCT STRATUS AT KMSN THROUGH THE PERIOD. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...NONE. && $$ UPDATE...MRC TODAY/TONIGHT AND AVIATION/MARINE...GEHRING MONDAY THROUGH SATURDAY...COLLAR