Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/23/13


AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1039 PM MDT SUN OCT 20 2013 .SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT) ISSUED AT 233 PM MDT SUN OCT 20 2013 IN NW FLOW ALOFT THE INITIAL VORTICITY MAXIMUM HAS PASSED TO THE SE OF THE STEAMBOAT-VAIL LINE PRODUCING ENHANCEMENT EAST OF VAIL PASS THIS EARLY AFTERNOON. SNOTELS SHOW 2 INCHES IN THE MTNS EAST OF STEAMBOAT SPRINGS WITH HIGHER AMOUNTS IN THE PARK RANGE NEAR THE WYOMING BORDER. SNOW ACCUMULATION LEVEL THIS AFTERNOON IS AROUND 9KFT THERE. SOME LESS ORGANIZED ENERGY WILL ROLL OVER THE ELKHEADS-PARK-GORE RANGES THIS AFTERNOON BUT THIS FORCING ENDS BY SUNSET. LITTLE EXTRA ACCUMULATION IS EXPECTED EXCEPT PERHAPS IN THE HIGHEST ELEVATIONS OF THE ZIRKEL WILDERNESS. THE 18Z RAP AND HRRR END SHOWERS BY 6PM BUT THE NAM HOLDS ONTO SOME LIGHT OROGRAPHIC SNOW ON NORTH-FACING SLOPES INTO THE EVENING. ALL AGREE ITS ALL DONE BY MIDNIGHT. THEREFORE HAVE CUT BACK POPS FOR TONIGHT. SOME LOW-MID CLOUDS WILL LINGER OVERNIGHT MAINLY EAST OF A LINE FROM CRAIG SOUTH TO MONARCH PASS. OTHERWISE PARTIALLY CLEARING SKIES WILL KEEP TEMPERATURES BELOW NORMAL TONIGHT AND MONDAY. WITH THE PASSING OF THESE FINAL DISTURBANCES THIS EVENING THE WEST COAST RIDGE RELAXES INTO THE INTERMOUNTAIN WEST. BENIGN AND DRY NW FLOW CONTINUES THROUGH MONDAY NIGHT AND BEYOND. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 233 PM MDT SUN OCT 20 2013 DRY WITH A GRADUAL WARMING TREND AS THE LARGE-SCALE PATTERN CHANGES LITTLE. A BLOCKING UPPER RIDGE NEAR THE WEST COAST DRIFTS OVER THE GREAT BASIN BY MIDWEEK BEFORE RETREATING BACK WESTWARD...WHILE A LARGE TROUGH REMAINS OVER THE CENTRAL AND EASTERN PART OF THE COUNTRY. NORTHWEST FLOW ON TUESDAY BECOMES WEST TO SOUTHWEST WEDNESDAY-THURSDAY AS A WEAK WAVE UNDERCUTS THE RIDGE AND CROSSES THE SOUTHERN GREAT BASIN...SWITCHING BACK TO NORTHWEST FRIDAY AS THE WAVE PASSES BY TO OUR SOUTH. THIS WILL BRING SOME CLOUDS TO CENTRAL AND SOUTHERN PARTS OF THE FORECAST AREA BUT LITTLE OR NO PRECIPITATION...AND WILL KEEP THE FORECAST DRY. DAYTIME TEMPERATURES WILL BE NEAR TO A LITTLE ABOVE NORMAL WHILE THE NIGHTS AVERAGE NEAR NORMAL. AN UPPER LOW IS EXPECTED TO PINCH OFF FROM THE NORTHERN JET STREAM OVER THE NERN PACIFIC OCEAN AND GRADUALLY SETTLE OFF THE CA COAST AND UNDERNEATH THE RIDGE BY LATE FRIDAY. MODELS OFTEN HAVE DIFFICULTY HANDLING THESE CUT-OFF LOWS...AND THE GFS AND ECMWF SHOW DIFFERENT SOLUTIONS BY NEXT MONDAY. BOTH INDICATE DRY WEATHER STILL NEXT WEEKEND SO WILL CONTINUE WITH THAT FOR NOW...BUT CONFIDENCE IS LOWERING BY SUNDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1040 PM MDT SUN OCT 20 2013 MID LEVEL CLOUDS CONTINUE OVER THE NORTHERN AND CENTRAL MOUNTAINS AT THIS HOUR WITH SOME -SN BEING REPORTED. NO TAF SITES REPORTING CONDITIONS BELOW MVFR AND EXPECT THIS TO CONTINUE THROUGH THE NIGHT AND WITH HIGH PRESSURE BUILDING IN TOMORROW...VFR WILL BE COMMON ACROSS EASTERN UTAH AND WESTERN COLORADO. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...JOE LONG TERM...JAD AVIATION...TGR
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1100 PM EDT TUE OCT 22 2013 .SYNOPSIS... A COLD FRONT WILL PASS FARTHER TO THE SOUTH AND EAST OF THE AREA OVERNIGHT. LOW PRESSURE WILL START TO DEVELOP OFF THE MID ATLANTIC COAST ON WEDNESDAY...AND THEN PASS TO THE EAST WHILE INTENSIFYING WEDNESDAY NIGHT. A WEAK LOW PRESSURE TROUGH WILL MOVE ACROSS THE AREA ON THURSDAY. HIGH PRESSURE WILL THEN BUILD TO THE SOUTH ON FRIDAY...AND SLIDE EAST ON ON SATURDAY. A FRONTAL SYSTEM WILL MOVE THROUGH ON SUNDAY...FOLLOWED BY HIGH PRESSURE EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... MINOR ADJUSTMENTS TO TEMPS AND DEWPOINTS AS WELL AS CLOUD COVERAGE. THERE IS A GOOD CONSENSUS AMONGST MODEL GUIDANCE THAT THE FORECAST AREA STAYS DRY THROUGH TONIGHT. HRRR HAS CONTINUED TO TREND SLOWER WITH THE ONSET OF LIGHT RAIN...HOLDING OFF UNTIL WEDNESDAY MORNING WITH ANY LIGHT RAIN. REMOVED POPS FOR TONIGHT. STILL KEEPING PATCHY FROST FOR THE OVERNIGHT PERIOD FOR INTERIOR AREAS. MIN TEMPS WILL LIKELY BE ACHIEVED AROUND MIDNIGHT TO AN HOUR OR TWO PROCEEDING MIDNIGHT. THEN TEMPS WILL SLOWLY DECREASE OR BECOME NEARLY STEADY AS A THICKENING MID-HIGH LEVEL CLOUD DECK BEGINS TO MOVE IN FROM WEST TO EAST...AND CAUSES RERADIATION OF LONGWAVE IR. A COLD FRONT WILL PUSH FARTHER SOUTH AND EAST OF THE AREA OVERNIGHT WITH MORE MID TO HIGH CLOUDS MOVING IN FROM THE WEST. THIS WILL BE VIA MID LEVEL ISENTROPIC LIFT AND DCVA FROM A WEAK MID LEVEL SHORTWAVE AHEAD OF AN APPROACHING UPPER TROUGH. THE CLOUDS PLUS STRONGER WINDS JUST OFF THE SFC SHOULD BE ENOUGH TO PREVENT FROST FROM BECOMING WIDESPREAD. EXPECT LOWS FROM 35-40 INLAND AND NEAR PINE PARRENS OF LI...TO THE LOWER AND MID 40S MOST ELSEWHERE...TO THE UPPER 40S INVOF NYC. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... AFOREMENTIONED COOL AIR MASS WILL INTERACT WITH THE GULF STREAM TO ENHANCE A LOW LEVEL BAROCLINIC ZONE NORTH OF THE GULF STREAM. A POTENT MID LEVEL SHORTWAVE WILL INTERACT WITH THIS ZONE TO SPAWN A WEAK SFC LOW OFF THE MID ATLANTIC COAST WED MORNING... WHICH SHOULD THEN MOVE TO THE NE. SIDED MORE WITH A GFS/NAM VS ECMWF SOLUTION FOR THE EVOLUTION OF THIS SYSTEM. STRONG MID LEVEL DCVA VIA A STRONG VORT MAX ROUNDING THE BASE OF THE APPROACHING UPPER TROUGH...PLUS DEVELOPING H7-8 FRONTOGENETIC FORCING AND NEGATIVE SATURATED H7-5 EPV...SHOULD LEAD TO PDS OF MODERATE RAIN OUT EAST. EXACT PLACEMENT OF BANDS OF HEAVIER RAIN STILL SOMEWHAT IN QUESTION GIVEN THE MESOSCALE FORCING INVOLVED...THEIR MOST LIKELY LOCATION ATTM APPEARS TO BE ACROSS CENTRAL/EASTERN LONG ISLAND AND SE CT. MEANWHILE MUCH OF THE LOWER HUDSON VALLEY AND INTERIOR NE NJ MAY SEE VERY LITTLE IN THE WAY OF PRECIP..BUT IF PRECIP DOES DEVELOP THERE EARLY ENOUGH IN THE MORNING A FEW SLEET PELLETS NOT OUT OF THE QUESTION WITH SOME LOW LEVEL DRY AIR TO BE OVERCOME AND WET-BULB TEMPS IN MOST OF THE VERTICAL COLUMN AOB FREEZING. A NE-N BREEZE PLUS CLOUD COVER AND PRECIP WILL LEAD TO A RATHER COOL DAY...WITH HIGHS ONLY IN THE UPPER 40S IN THE HIGHER ELEVATIONS AND LOWER 50S ELSEWHERE. AS THE LOW HEADS OFF TO THE EAST WED NIGHT...EXPECT DECENT CAA TO LEAD TO LOWS IN THE 30S AND LOWER 40S. IF CAA IS STRONG ENOUGH PER COLDER MAV GUIDANCE...INTERIOR SECTIONS COULD SEE LOWS AOB FREEZING. NOT ENOUGH CONFIDENCE TO ISSUE A FREEZE WATCH YET...BUT THIS COULD CHANGE WITH LATER FORECASTS SO HAVE MENTIONED IN HWO. && .LONG TERM /THURSDAY THROUGH TUESDAY/... A BROAD TROUGH OVER THE EASTERN HALF OF NOAM WILL REMAIN THROUGH THE END OF THE WEEK. THE TROF AXIS IS FORECAST TO PASS THROUGH ON FRI WITH RISING HEIGHTS THEREAFTER. ZONAL FLOW RETURNS BRIEFLY ON SAT...BUT ANOTHER TROUGH WILL MOVE THROUGH ON SUN. NEARLY ZONAL FLOW THEN RETURNS FOR EARLY NEXT WEEK. AT THE SFC...A WEAK TROF WILL MOVE ACROSS THE AREA ON THU. A W TO NW FLOW WILL PREVAIL BEHIND IT...WITH THE LAKE EFFECT MACHINE TURNING ON THU AND FRI. CURRENTLY...IT LOOKS AS IF ALL PRECIP WILL REMAIN N AND W OF THE FORECAST AREA...BUT DO EXPECT AN INCREASE IN CLOUD COVER ACROSS NW ZONES. COOLER AIR MOVING OVER THE WARMER OCEAN MAY ALSO CAUSE OCEAN EFFECT SHOWERS OVER THE WATERS. HIGH PRES BUILDING TO THE S FRI AND SAT WILL RESULT IN DRY CONDS. THE BEST CHC FOR ANY PRECIP WILL BE WITH A FRONTAL SYSTEM MOVING THROUGH ON SUN. MODELS KEEP THE BULK OF THE PRECIP N OF THE AREA WHERE THE BETTER DYNAMICS WILL BE AND SINCE THE TREND OVER THE LAST SEVERAL MONTHS HAS BEEN DRIER...KEPT THE SCHC POPS THAT WERE PREVIOUSLY FORECAST. CANADIAN HIGH PRES THEN BUILDS TOWARDS THE AREA EARLY NEXT WEEK. TEMPS WILL GENERALLY BE 5 TO 10 DEGREES BELOW NORMAL LEVELS THROUGH THE PERIOD. THERE IS THE POSSIBILITY OF FREEZING LOWS FOR PORTIONS OF INTERIOR ZONES ON THU NIGHT AND MUCH OF THE INTERIOR FRI NIGHT. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... A COLD FRONT MOVES THROUGH OVERNIGHT AS LOW PRESSURE PASSES TO THE SOUTH WEDNESDAY. WINDS SHIFT TO THE N BY MIDNIGHT. SPEEDS REMAIN GENERALLY UNDER 10 KTS. WINDS TURN TO THE NE WEDNESDAY MORNING...THEN BACK AGAIN TO THE N IN THE AFTERNOON. TIMING COULD BE OFF BY AN HOUR OR TWO WITH THE WIND SHIFTS. INCREASING MID AND HIGH CLOUDS ARE EXPECTED OVERNIGHT. CEILINGS LOWER WEDNESDAY MORNING...WITH LOW END VFR OR HIGH END MVFR CEILINGS POSSIBLE WEDNESDAY AFTERNOON. LIGHT RAIN POSSIBLE...ESPECIALLY FOR NYC METRO AND AIRPORTS TO THE EAST OVER LONG ISLAND AND SE CT. INTERIOR AIRPORTS (KSWF) SHOULD REMAIN VFR ALL DAY WITH VERY LITTLE RAIN. OUTLOOK FOR 03Z THURSDAY THROUGH SUNDAY... .WEDNESDAY NIGHT...BECOMING VFR WITH CLEARING SKIES. .THURSDAY...MOSTLY VFR. CHC WNW GUSTS 25KT. .THURSDAY NIGHT-SATURDAY...VFR. .SATURDAY NIGHT-SUNDAY...MVFR CONDITIONS IN -SHRA PSBL WITH A COLD FRONTAL PASSAGE. && .MARINE... WIND GUSTS AFTER COLD FROPA ON THE OCEAN COULD NEAR 25 KT TONIGHT. ALSO...N-NW FLOW ON THE BACK SIDE OF DEPARTING LOW PRESSURE COULD GUST CLOSE TO 25 KT LATE DAY WED...WITH OCEAN SEAS POSSIBLY NEARING 5 FT ATTM. NO SCA ISSUED ATTM. A MODERATE WESTERLY FLOW MAY CAUSE MARGINAL SCA CONDS ON THE EASTERN OCEAN WATERS THU/THU NIGHT. SUB-ADVY CONDS ARE THEN EXPECTED THROUGH SAT WITH HIGH PRES BUILDING S OF THE WATERS. AN INCREASING SW FLOW AHEAD OF A COLD FRONT SAT NIGHT COULD CAUSE SCA CONDS TO RETURN...PRIMARILY FOR SEAS ON THE OCEAN WATERS. && .HYDROLOGY... THERE COULD BE SOME ISOLD 1/2 INCH RAINFALL TOTALS ON LONG ISLAND ON WED. OTHERWISE...MOST OF NYC LONG ISLAND AND SOUTHERN CT SHOULD SEE 1/4 TO 1/2 INCH OF RAIN...WITH LESS AMTS NORTH/WEST. NO SIGNIFICANT PRECIP EXPECTED THEREAFTER. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...GOODMAN/24 NEAR TERM...GOODMAN/JM SHORT TERM...GOODMAN LONG TERM...GOODMAN/24 AVIATION...PW MARINE...GOODMAN/24 HYDROLOGY...GOODMAN
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
835 PM EDT TUE OCT 22 2013 .UPDATE (TONIGHT AND WEDNESDAY)... 23/00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING AN AMPLIFIED UPPER LEVEL PATTERN IN PLACE OVER THE CONUS...HIGHLIGHTED BY A DEEP AND COLD FALL TROUGH OVER THE CENTRAL AND EASTERN STATES. THIS TROUGH IS ANCHORED BY A LARGE CUT-OFF LOW SPINNING OVER ONTARIO/QUEBEC. MOST INFLUENTIAL TO OUR LOCAL FORECAST IS SHORTWAVE ENERGY ROUNDING THE BASE OF THE MAIN TROUGH ALONG THE NORTHERN GULF COAST. THIS SHORTWAVE AXIS IS CURRENTLY EJECTING EASTWARD FROM THE SOUTHERN MS VALLEY WITH PRONOUNCED SUBSIDENCE/DRYING SHOWN IN WV IMAGERY IN ITS WAKE. AHEAD OF THIS FEATURE...A DEEP BAND OF MID/UPPER LEVEL MOISTURE IS STREAMING NORTHWARD OVER THE CENTRAL/EASTERN GULF AND OVER THE FLORIDA PENINSULA. THE DEEP LAYER MOISTURE IS COMBINING WITH A BROAD REGION OF SYNOPTIC SUPPORT/QG FORCING AHEAD OF THE SHORTWAVE AND UPPER LEVEL DIVERGENCE WITHIN THE RRQ OF AN IMPRESSIVE UPPER JET OVER THE EASTERN SEABOARD TO SUPPORT A BAND OF WIDESPREAD SHOWERS/ISOLATED STORMS MOVING ASHORE FROM THE EASTERN GULF. THIS ACTIVITY IS A BIT AHEAD OF SCHEDULE...ESPECIALLY FOR THE TAMPA BAY AREA AND SOUTHWARD. HOWEVER...THIS EARLY ARRIVAL IS NOT OVERLY SURPRISING...AS NUMERICAL WEATHER PREDICTION IS OFTEN BIASED SLOW ON THE EVOLUTION OF SYNOPTIC ASCENT FEATURES. WHILE THE BEGINNING OF THE HIGHER RAIN CHANCES NEEDED TO UPDATED FOR THE SOUTHERN HALF OF THE AREA...NOT GOING TO MAKE MUCH ADJUSTMENT TO ENDING TIMES JUST YET. THE TIMING OF THE COLD FRONT AND PASSAGE OF THE SHORTWAVE TO OUR NORTH STILL LOOKS GENERALLY ON TRACK AND SO EVEN THOUGH THERE MAY BE A BREAK FOR A WHILE AFTER THE INITIAL BAND...THERE IS NOT MUCH IN THE WAY OF NEGATIVE FACTORS TO PREVENT ADDITIONAL SHOWER DEVELOPMENT DURING THE LATER OVERNIGHT HOURS. COLD FRONT WHICH APPEARS DISORGANIZED TO OUR NORTH CURRENTLY...IS SHOWN BY ALL GUIDANCE MEMBERS TO ORGANIZED AND DRIVE SOUTHWARD INTO THE NATURE COAST DURING THE SECOND HALF OF THE NIGHT. THIS SHOULD QUICKLY DECREASE RAIN CHANCES TO THE NORTH OF TAMPA BAY BY THE TIME WE APPROACH DAWN. AN ENSEMBLE APPROACH SUGGESTS THAT THE FRONT WILL CROSS THE I-4 CORRIDOR AROUND SUNRISE (OR SHORTY THEREAFTER)...AND THEN PROGRESS SOUTH TO THE FORT MYERS AREA BY EARLY AFTERNOON. BY MIDDAY...ALL LINGERING SCT RAIN CHANCES LOOK TO HAVE BEEN SUPPRESSED SOUTH OF TAMPA BAY...AND EVEN LIKELY EXIT OUR FAR SOUTHERN ZONES BY LATE AFTERNOON. THE PASSAGE OF THIS FRONT WILL THEN SET UP AN EXTENDED PERIOD OF DRY AND SEASONABLE COOLER WEATHER FOR OUR FORECAST AREA THAT WILL LAST THROUGH THE UPCOMING WEEKEND. HAVE A GREAT NIGHT AND ENJOY THE UPCOMING FALL PATTERN. && .AVIATION... SHOWERS WITH GUSTY WINDS ARE MOVING THROUGH THE NORTHERN TERMINALS THIS EVENING AND WILL PUSH INTO THE SOUTHERN TERMINALS LATER TONIGHT. WIND GUSTS HAVE BEEN AROUND 25KTS AND HAVE THIS IN THE TEMPO ALONG WITH SOME MVFR VSBYS/CIGS. SOME LIGHT RAIN THAT GENERALLY KEEPS VFR CONDITIONS IN PLACE WILL CONTINUE TO BE POSSIBLE OVERNIGHT ALONG WITH SOME PATCHY GROUND FOG. CONDITIONS SHOULD IMPROVE THROUGH THE DAY WEDNESDAY WITH A MODERATE NORTH WIND DEVELOPING. && .MARINE... THE PASSAGE OF A COLD FRONT THROUGH THE EASTERN GULF OF MEXICO LATER TONIGHT AND WEDNESDAY WILL BRING INCREASINGLY ROUGH WINDS AND SEAS IN ITS WAKE. CONDITIONS WILL REACH CAUTIONARY LEVELS NORTH OF TAMPA BAY LATE TONIGHT AND THEN THE CAUTIONARY LEVEL WINDS AND SEAS WILL QUICKLY SPREAD SOUTHWARD OVER THE REMAINDER OF THE FORECAST WATERS ON WEDNESDAY. CAUTIONARY TO ADVISORY LEVEL NORTHEAST WINDS WILL THEN BE IN THE FORECAST INTO AT LEAST THE FIRST HALF OF THE WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... TPA 72 83 59 79 / 70 30 10 0 FMY 74 85 67 83 / 60 60 20 10 GIF 70 84 58 81 / 60 40 10 10 SRQ 72 84 60 82 / 70 50 10 10 BKV 68 82 49 80 / 60 20 10 0 SPG 74 82 64 78 / 70 40 10 0 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE...MROCZKA COLSON...AVIATION
AREA FORECAST DISCUSSION
NWS MIAMI FL
804 PM EDT TUE OCT 22 2013 .UPDATE... A COLD FRONT EXTENDING FROM SOUTHERN GEORGIA SOUTHWEST INTO THE EASTERN GULF OF MEXICO WILL CONTINUE TO MOVE SOUTHEAST DOWN THE SUNSHINE STATE TONIGHT AND THROUGH SOUTH FLORIDA ON WEDNESDAY. A PRE-FRONTAL TROUGH OF LOW PRESSURE WAS ALSO LOCATED OVER THE SOUTHEASTERN GULF OF MEXICO WHICH WILL MOVE EAST AND THROUGH SOUTH FLORIDA. THESE TWO SYSTEMS WILL KEEP A SOUTHWEST STEERING FLOW OVER SOUTH FLORIDA TONIGHT ALLOWING FOR TROPICAL MOISTURE TO WORK INTO THE AREA FROM THE GULF OF MEXICO. SO THE SHOWERS AND THUNDERSTORMS OVER THE EASTERN GULF OF MEXICO WILL CONTINUE TO WORK EAST AND INTO THE WESTERN AREAS OF SOUTH FLORIDA TONIGHT. THEREFORE...THE POPS WILL BE RAISED TO CHANCE CAT FOR THE WESTERN AREAS TONIGHT ALONG WITH ADDING THUNDER WORDING TO THE FORECAST. SHOWERS AND THUNDERSTORMS HAVE ALSO DEVELOPED OVER WESTERN CUBA EARLY THIS EVENING. THESE SHOWERS AND THUNDERSTORMS SHOULD MOVE NORTH NORTHEAST INTO THE FLORIDA KEYS AND POSSIBLY INTO THE SOUTHEASTERN AREAS OF SOUTH FLORIDA LATE TONIGHT INTO EARLY WEDNESDAY MORNING INCLUDING THE ADJACENT COASTAL WATERS. SO HAVE RAISED THE POPS UP OVER THE SOUTHEASTERN AREAS OF SOUTH FLORIDA TO LOW END CHANCE TONIGHT ALONG WITH ADDING THUNDER WORDING TO THE FORECAST. REST OF SOUTH FLORIDA SHOULD SEE ISOLATED SHOWERS TONIGHT. SO WILL KEEP A SLIGHT CHANCE OF POPS IN FOR THESE AREAS FOR TONIGHT. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES ARE PLANNED. && .UDPATED...54/BNB .PREV DISCUSSION... /ISSUED 716 PM EDT TUE OCT 22 2013/ AVIATION...VFR WILL PREVAIL. HOWEVER, A FEW SHRA ARE POSSIBLE NEAR KAPF TONIGHT, ESPECIALLY LATE, ASSOCIATED WITH ACTIVITY DEVELOPING AHEAD OF THE COLD FRONT. THIS ACTIVITY IS EXPECTED TO SPREAD SE ON WED AHEAD OF THE FRONT, WITH SCATTERED SHRA AND ISOLATED TSRA POSSIBLE. FOR NOW, KEPT VCSH AT ALL TERMINALS AND WILL MONITOR FOR POSSIBLE TSRA DEVELOPMENT AND UPDATE AS NEEDED. WINDS WILL PREVAIL LIGHT OUT OF THE SW OVERNIGHT BECOMING W-NW 5-10 KT ON WED. /GREGORIA && PREV DISCUSSION... /ISSUED 246 PM EDT TUE OCT 22 2013/ SHORT TERM (TONIGHT-THURSDAY NIGHT)... THE LATEST WRF/HRRR MODEL SOLUTIONS INDICATE MAINLY SCATTERED SEA BREEZE DRIVEN SHOWERS/TSTMS CONTINUING TO INITIATE ACROSS PORTIONS OF THE AREA...THEN BECOMING CONCENTRATED OVER THE NORTHEASTERN SECTIONS OF THE AREA OR AROUND THE LAKE REGION TO THE PALM BEACH COAST THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS BEFORE DIMINISHING. THE LATEST SHORT-RANGE MODEL GUIDANCE HAS INITIALIZED WELL WITH THE CURRENT SYNOPTIC PATTERN AND GENERALLY INDICATES THE ABOVE AVERAGE TEMPERATURES PERSISTING THROUGH WEDNESDAY AS A COLD FRONT APPROACHES AND MOVES INTO THE LOCAL AREA. OVERNIGHT LOWS ARE FORECAST TO DROP INTO THE 70S TONIGHT AND RETURN TO THE MID TO UPPER 80S THROUGH THE AFTERNOON PERIOD WEDNESDAY...WHICH IS AROUND 3-5 DEGREES WARMER THAN AVERAGE FOR THIS PERIOD. MODEL SOUNDINGS AROUND THE LOCAL AREA INDICATE THE DEEP SOUTHWEST FLOW ALONG WITH INCREASING DEEP LAYER MOISTURE CONTINUING AHEAD OF THE SHORTWAVE TROUGH CURRENTLY MOVING OVER THE MS VALLEY REGION. UPPER HEIGHTS WILL BEGIN TO FALL LATER TONIGHT THROUGH THE END OF THE PERIOD AS THIS UPPER TROUGH APPROACHES AND MOVES OVER THE EAST COAST. THE FRONTAL BOUNDARY IS FORECAST TO PUSH THROUGH THE LOCAL AREA THROUGH THE DAY WEDNESDAY WITH THE LOW-LEVEL WINDS FORECAST TO QUICKLY VEER AND INCREASE OUT OF THE NORTHEAST WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. NORTHEAST WINDS WILL LIKELY BECOME GUSTY THROUGH THIS TIME THURSDAY...ESPECIALLY OVER THE ADJACENT MARINE AREAS AND ALONG THE EAST COAST. ALTHOUGH MUCH DRIER AND COOLER AIR WILL BEGIN TO SPREAD SOUTH INTO PORTIONS OF THE AREA THROUGH THE DAY THURSDAY...THE RAIN CHANCES WILL REMAIN UP OVER THE SOUTHERN HALF OF THE LOCAL AREA WHERE MODEL PWATS REMAIN AROUND THE 2" MARK. IN ADDITION TO THE RAIN CHANCES THURSDAY...SOME TSTMS WILL REMAIN POSSIBLE THROUGH THE FIRST HALF OF THE DAY OVER THESE SOUTHERN AREAS. LONG TERM (FRIDAY-MONDAY)... MODELS REMAIN IN AGREEMENT WITH A SECONDARY FRONT SURGING THROUGH THE AREA FRIDAY BRINGING A MUCH DRIER AIR MASS INTO SOUTH FLORIDA ALONG WITH BELOW NORMAL TEMPERATURES. FAIRLY WIDESPREAD 50S SHOULD BE SEEN ACROSS INTERIOR AREAS BOTH SATURDAY AND SUNDAY MORNINGS WITH HIGHS EACH DAY IN THE LOW 80S ACROSS THE EAST COAST. LONG-RANGE MODELS INDICATE THAT THE DRY PATTERN WILL CONTINUE ACROSS THE AREA INTO THE FIRST PART OF NEXT WEEK WITH NORTHEAST SURFACE FLOW PREVAILING. AVIATION...18Z TAFS OCT. 13 2013 CURRENTLY HAVE A FEW SHRA MOVING NNE ALONG THE EAST COAST SEA BREEZE AND THIS TREND WILL LIKELY TO CONTINUE THROUGH THE AFTERNOON WITH ADDITIONAL DEVELOPMENT OVER INLAND AREAS. THERE COULD ALSO BE A TSRA OR TWO BUT OVERALL CONFIDENCE AND COVERAGE TOO LOW TO PLACE IN THE FORECAST AT THIS TIME. SOME OF THE ACTIVITY COULD PERSIST INTO THE EVENING, HOWEVER THE HRRR HINTS AT LITTLE ACTIVITY PAST 00Z. SOME LOCATIONS COULD HAVE VERY BRIEF MVFR OR EVEN IFR BUT TIMING AND EXACT LOCATION WITH LOW COVERAGE ALWAYS DIFFICULT TO FORECAST SO LEFT LIMITED RESTRICTIONS FOR NOW AND WILL AMEND IF NECESSARY. MOST OF THE CONVECTION WILL BE WELL EAST OF KAPF UNTIL LATER IN THE FORECAST WHEN THE FRONT SHIFTS SOUTH AND MAY HAVE AN INCREASE IN SHRA OVER THE GULF WATERS AFT 06Z. KOB MARINE... LIGHT SOUTH-SOUTHEAST WINDS WILL SHIFT TO THE SOUTH- SOUTHWEST LATER TONIGHT AHEAD OF AN APPROACHING COLD FRONT. SCATTERED SHOWERS DEVELOPING OUT AHEAD OF THIS BOUNDARY WILL REMAIN POSSIBLE THROUGH THE MID-WEEK TIME FRAME. DRIER AIR ALONG WITH INCREASING WINDS AND SEAS ARE FORECAST TO SPREAD SOUTH OVER THE MARINE AREAS IN THE WAKE OF THE FRONT BEGINNING THURSDAY AND CONTINUING INTO THE UPCOMING WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 74 86 70 81 / 20 50 40 20 FORT LAUDERDALE 77 87 73 82 / 30 40 40 30 MIAMI 77 88 72 82 / 30 40 40 40 NAPLES 75 87 66 84 / 40 40 30 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS MIAMI FL
716 PM EDT TUE OCT 22 2013 .AVIATION...VFR WILL PREVAIL. HOWEVER, A FEW SHRA ARE POSSIBLE NEAR KAPF TONIGHT, ESPECIALLY LATE, ASSOCIATED WITH ACTIVITY DEVELOPING AHEAD OF THE COLD FRONT. THIS ACTIVITY IS EXPECTED TO SPREAD SE ON WED AHEAD OF THE FRONT, WITH SCATTERED SHRA AND ISOLATED TSRA POSSIBLE. FOR NOW, KEPT VCSH AT ALL TERMINALS AND WILL MONITOR FOR POSSIBLE TSRA DEVELOPMENT AND UPDATE AS NEEDED. WINDS WILL PREVAIL LIGHT OUT OF THE SW OVERNIGHT BECOMING W-NW 5-10 KT ON WED. /GREGORIA && .PREV DISCUSSION... /ISSUED 246 PM EDT TUE OCT 22 2013/ SHORT TERM (TONIGHT-THURSDAY NIGHT)... THE LATEST WRF/HRRR MODEL SOLUTIONS INDICATE MAINLY SCATTERED SEA BREEZE DRIVEN SHOWERS/TSTMS CONTINUING TO INITIATE ACROSS PORTIONS OF THE AREA...THEN BECOMING CONCENTRATED OVER THE NORTHEASTERN SECTIONS OF THE AREA OR AROUND THE LAKE REGION TO THE PALM BEACH COAST THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS BEFORE DIMINISHING. THE LATEST SHORT-RANGE MODEL GUIDANCE HAS INITIALIZED WELL WITH THE CURRENT SYNOPTIC PATTERN AND GENERALLY INDICATES THE ABOVE AVERAGE TEMPERATURES PERSISTING THROUGH WEDNESDAY AS A COLD FRONT APPROACHES AND MOVES INTO THE LOCAL AREA. OVERNIGHT LOWS ARE FORECAST TO DROP INTO THE 70S TONIGHT AND RETURN TO THE MID TO UPPER 80S THROUGH THE AFTERNOON PERIOD WEDNESDAY...WHICH IS AROUND 3-5 DEGREES WARMER THAN AVERAGE FOR THIS PERIOD. MODEL SOUNDINGS AROUND THE LOCAL AREA INDICATE THE DEEP SOUTHWEST FLOW ALONG WITH INCREASING DEEP LAYER MOISTURE CONTINUING AHEAD OF THE SHORTWAVE TROUGH CURRENTLY MOVING OVER THE MS VALLEY REGION. UPPER HEIGHTS WILL BEGIN TO FALL LATER TONIGHT THROUGH THE END OF THE PERIOD AS THIS UPPER TROUGH APPROACHES AND MOVES OVER THE EAST COAST. THE FRONTAL BOUNDARY IS FORECAST TO PUSH THROUGH THE LOCAL AREA THROUGH THE DAY WEDNESDAY WITH THE LOW-LEVEL WINDS FORECAST TO QUICKLY VEER AND INCREASE OUT OF THE NORTHEAST WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. NORTHEAST WINDS WILL LIKELY BECOME GUSTY THROUGH THIS TIME THURSDAY...ESPECIALLY OVER THE ADJACENT MARINE AREAS AND ALONG THE EAST COAST. ALTHOUGH MUCH DRIER AND COOLER AIR WILL BEGIN TO SPREAD SOUTH INTO PORTIONS OF THE AREA THROUGH THE DAY THURSDAY...THE RAIN CHANCES WILL REMAIN UP OVER THE SOUTHERN HALF OF THE LOCAL AREA WHERE MODEL PWATS REMAIN AROUND THE 2" MARK. IN ADDITION TO THE RAIN CHANCES THURSDAY...SOME TSTMS WILL REMAIN POSSIBLE THROUGH THE FIRST HALF OF THE DAY OVER THESE SOUTHERN AREAS. LONG TERM (FRIDAY-MONDAY)... MODELS REMAIN IN AGREEMENT WITH A SECONDARY FRONT SURGING THROUGH THE AREA FRIDAY BRINGING A MUCH DRIER AIR MASS INTO SOUTH FLORIDA ALONG WITH BELOW NORMAL TEMPERATURES. FAIRLY WIDESPREAD 50S SHOULD BE SEEN ACROSS INTERIOR AREAS BOTH SATURDAY AND SUNDAY MORNINGS WITH HIGHS EACH DAY IN THE LOW 80S ACROSS THE EAST COAST. LONG-RANGE MODELS INDICATE THAT THE DRY PATTERN WILL CONTINUE ACROSS THE AREA INTO THE FIRST PART OF NEXT WEEK WITH NORTHEAST SURFACE FLOW PREVAILING. AVIATION...18Z TAFS OCT. 13 2013 CURRENTLY HAVE A FEW SHRA MOVING NNE ALONG THE EAST COAST SEA BREEZE AND THIS TREND WILL LIKELY TO CONTINUE THROUGH THE AFTERNOON WITH ADDITIONAL DEVELOPMENT OVER INLAND AREAS. THERE COULD ALSO BE A TSRA OR TWO BUT OVERALL CONFIDENCE AND COVERAGE TOO LOW TO PLACE IN THE FORECAST AT THIS TIME. SOME OF THE ACTIVITY COULD PERSIST INTO THE EVENING, HOWEVER THE HRRR HINTS AT LITTLE ACTIVITY PAST 00Z. SOME LOCATIONS COULD HAVE VERY BRIEF MVFR OR EVEN IFR BUT TIMING AND EXACT LOCATION WITH LOW COVERAGE ALWAYS DIFFICULT TO FORECAST SO LEFT LIMITED RESTRICTIONS FOR NOW AND WILL AMEND IF NECESSARY. MOST OF THE CONVECTION WILL BE WELL EAST OF KAPF UNTIL LATER IN THE FORECAST WHEN THE FRONT SHIFTS SOUTH AND MAY HAVE AN INCREASE IN SHRA OVER THE GULF WATERS AFT 06Z. KOB MARINE... LIGHT SOUTH-SOUTHEAST WINDS WILL SHIFT TO THE SOUTH- SOUTHWEST LATER TONIGHT AHEAD OF AN APPROACHING COLD FRONT. SCATTERED SHOWERS DEVELOPING OUT AHEAD OF THIS BOUNDARY WILL REMAIN POSSIBLE THROUGH THE MID-WEEK TIME FRAME. DRIER AIR ALONG WITH INCREASING WINDS AND SEAS ARE FORECAST TO SPREAD SOUTH OVER THE MARINE AREAS IN THE WAKE OF THE FRONT BEGINNING THURSDAY AND CONTINUING INTO THE UPCOMING WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 74 86 70 81 / 30 50 40 20 FORT LAUDERDALE 77 87 73 82 / 30 40 40 30 MIAMI 75 88 72 82 / 30 40 40 40 NAPLES 74 87 66 84 / 30 40 30 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
410 AM EDT MON OCT 21 2013 .DISCUSSION... TODAY/TONIGHT...WEAK FRONT CURRENTLY ACROSS CENTRAL FLORIDA FROM NORTH OF TAMPA TO THE CAPE IS STARTING TO SHOW SIGNS OF A SLOW NORTHWARD MOVEMENT. THIS MOTION WILL LIKELY CONTINUE AND MAY REACH JUST NORTH OF LAKE/VOLUSIA COUNTIES TODAY BEFORE STALLING OUT ONCE AGAIN. WEAK LOW LEVEL WIND FIELD WILL PERSIST OVER THE REGION WITH SEA BREEZE BOUNDARIES DEVELOPING AND MOVING INLAND. BEST CHANCE FOR SHOWERS AND MAYBE EVEN A FEW STORMS WILL EXIST ACROSS THE INTERIOR LATER THIS AFTERNOON WITH ANY BOUNDARY COLLISIONS OR INTERACTIONS WITH THE FRONT. IF ANY STORMS DO DEVELOP A SOUTHWEST STEERING FLOW WILL PUSH THIS CONVECTION BACK TOWARD THE COAST INTO THE EARLY EVENING HOURS. HIGHS WILL RANGE FROM THE MID TO UPPER 80S WITH A FEW LOCATIONS REACHING AROUND 90 DEGREES ACROSS INTERIOR LOCATIONS SOUTH OF ORLANDO. OVERNIGHT LOWS WILL GENERALLY BE AROUND 70 DEGREES TO LOW 70S. TUE-FRI...ANTICYCLONIC FLOW AROUND WRN ATLC MID LEVEL RIDGE WILL BECOME BROADLY CYCLONIC AS DEVELOPING ERN CONUS/WRN ATLC TROUGH CAUSES H50 HEIGHT FALLS OF ABOUT 30-40M OVER THE FL PENINSULA. THIS WILL FINALLY CAVE IN THE RESISTANCE TO THE COOL FRONT... WHICH WILL GRADUALLY SAG INTO ON WEDNESDAY...PRECEDED BY INCRSG CLOUDS/MOISTURE AND RAIN CHANCES FROM LATE TUE THRU WED. MODEST STRIPE OF MID LEVEL VORTICITY COUPLED WITH RESPECTABLE UPPER DIVG IN TAIL OF DEPARTING RR QUAD OF 120KT+ SERN CONUS JET STREAK WILL PUSH OVHD..MAKING FOR A CLOUDY AND SOMEWHAT WET ~36 HR PERIOD... FOLLOWED BY DRIER/COOLER WEATHER THU. RAIN CHCS WILL AVERAGE ABOUT 40-50 PCT FOR TUE THROUGH WED...WITH PRECIP ENDING N-S WED EVENING. COOLER TEMPS WED DUE TO CLOUDS/PRECIP AND COOLER STILL ON THU OWING TO MODIFIED CAA. REINFORCING SURFACE HIGH MOVES INTO THE SERN CONUS FRI...WHICH WILL KEEP TEMPS FROM MODIFYING MUCH INTO THIS WEEKEND. SAT-MON...E-W ORIENTED SFC RIDGE OVER THE SERN CONUS WEEKEND OVER THE COURSE OF THIS WEEKEND WITH DRY CONDITIONS CONTINUING AND SLOWLY MODIFYING TEMPS. ANOTHER SHORT WAVE TROUGH SLIDES THROUGH THE SERN CONUS AND FL SUN NIGHT/EARLY MON BUT LOCAL AIR MASS APPEARS AS THOUGH IT MAY BE TOO DRY TO SUPPORT PRECIP...IN SPITE OF DECENT MID LEVEL LIFT. LARGE SURFACE HIGH BUILD OVER THE NERN CONUS WITH EASTERLY FLOW STRENGTHENING OVER FL EARLY NEXT WEEK. TEMPS NEAR TO SLIGHTLY BELOW NORMAL. && .AVIATION...NOT LOOKING AS FAVORABLE FOR WIDESPREAD STRATUS/FOG DEVELOPMENT THROUGH EARLY THIS MORNING...BUT SHOULD STILL SEE A FEW LOCATIONS WHERE TEMPO IFR/MVFR CONDS OCCUR THROUGH 13Z. ISO/SCT SHOWERS AND A FEW STORMS WILL BE POSSIBLE INTO THE AFTERNOON... MAINLY OVER THE INTERIOR...BUT RAIN CHANCES REMAIN LOW ENOUGH TO ONLY INCLUDE VCSH IN THE TAFS FOR NOW. && .MARINE... TODAY/TONIGHT...QUASI-STATIONARY FRONT WILL EXIST NEAR TO JUST NORTH OF THE VOLUSIA COUNTY WATERS TODAY INTO TONIGHT. RELATIVELY LIGHT AND VARIABLE WINDS THIS MORNING WILL BECOME ONSHORE AND THEN SWITCH TO THE SOUTH TONIGHT. SEAS WILL RANGE FROM 2-3 FEET. TUE-FRI...LIGHT OFFSHORE PRE-FRONTAL WINDS WILL INCREASE OUT OF THE NORTH IMMEDIATELY BEHIND THE COLD FRONT WED AND NE WED NIGHT. WINDS SLACKEN AND VEER A TAD ON THU BEFORE REINFORCING HIGH PRES AND ASCD NE WIND SURGE PUSH SEAS BACK UP ON FRIDAY. CONDITIONS OVER THE GULF STREAM WILL BE FAIRLY CHOPPY...ESPECIALLY WED AND FRI..GIVEN THE PREVAILING N-NE WIND FLOW. && .PRELIMINARY POINT TEMPS/POPS... DAB 84 70 82 68 / 20 20 50 50 MCO 88 71 86 70 / 30 20 40 50 MLB 87 72 85 71 / 20 20 40 50 VRB 88 72 88 70 / 20 20 40 40 LEE 88 71 85 68 / 30 20 40 50 SFB 87 71 86 69 / 30 20 50 50 ORL 88 72 86 70 / 30 20 40 50 FPR 88 71 87 70 / 20 20 40 40 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...WEITLICH LONG TERM/IMPACT WX....CRISTALDI
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
355 AM EDT MON OCT 21 2013 .DISCUSSION... TODAY/TONIGHT...WEAK FRONT CURRENTLY ACROSS CENTRAL FLORIDA FROM NORTH OF TAMPA TO THE CAPE IS STARTING TO SHOW SIGNS OF A SLOW NORTHWARD MOVEMENT. THIS MOTION WILL LIKELY CONTINUE AND MAY REACH JUST NORTH OF LAKE/VOLUSIA COUNTIES TODAY BEFORE STALLING OUT ONCE AGAIN. WEAK LOW LEVEL WIND FIELD WILL PERSIST OVER THE REGION WITH SEA BREEZE BOUNDARIES DEVELOPING AND MOVING INLAND. BEST CHANCE FOR SHOWERS AND MAYBE EVEN A FEW STORMS WILL EXIST ACROSS THE INTERIOR LATER THIS AFTERNOON WITH ANY BOUNDARY COLLISIONS OR INTERACTIONS WITH THE FRONT. IF ANY STORMS DO DEVELOP A NORTHWEST STEERING FLOW WILL PUSH THIS CONVECTION BACK TOWARD THE COAST INTO THE EARLY EVENING HOURS. HIGHS WILL RANGE FROM THE MID TO UPPER 80S WITH A FEW LOCATIONS REACHING AROUND 90 DEGREES ACROSS INTERIOR LOCATIONS SOUTH OF ORLANDO. OVERNIGHT LOWS WILL GENERALLY BE AROUND 70 DEGREES TO LOW 70S. TUE-FRI...ANTICYCLONIC FLOW AROUND WRN ATLC MID LEVEL RIDGE WILL BECOME BROADLY CYCLONIC AS DEVELOPING ERN CONUS/WRN ATLC TROUGH CAUSES H50 HEIGHT FALLS OF ABOUT 30-40M OVER THE FL PENINSULA. THIS WILL FINALLY CAVE IN THE RESISTANCE TO THE COOL FRONT... WHICH WILL GRADUALLY SAG INTO ON WEDNESDAY...PRECEDED BY INCRSG CLOUDS/MOISTURE AND RAIN CHANCES FROM LATE TUE THRU WED. MODEST STRIPE OF MID LEVEL VORTICITY COUPLED WITH RESPECTABLE UPPER DIVG IN TAIL OF DEPARTING RR QUAD OF 120KT+ SERN CONUS JET STREAK WILL PUSH OVHD..MAKING FOR A CLOUDY AND SOMEWHAT WET ~36 HR PERIOD... FOLLOWED BY DRIER/COOLER WEATHER THU. RAIN CHCS WILL AVERAGE ABOUT 40-50 PCT FOR TUE THROUGH WED...WITH PRECIP ENDING N-S WED EVENING. COOLER TEMPS WED DUE TO CLOUDS/PRECIP AND COOLER STILL ON THU OWING TO MODIFIED CAA. REINFORCING SURFACE HIGH MOVES INTO THE SERN CONUS FRI...WHICH WILL KEEP TEMPS FROM MODIFYING MUCH INTO THIS WEEKEND. SAT-MON...E-W ORIENTED SFC RIDGE OVER THE SERN CONUS WEEKEND OVER THE COURSE OF THIS WEEKEND WITH DRY CONDITIONS CONTINUING AND SLOWLY MODIFYING TEMPS. ANOTHER SHORT WAVE TROUGH SLIDES THROUGH THE SERN CONUS AND FL SUN NIGHT/EARLY MON BUT LOCAL AIR MASS APPEARS AS THOUGH IT MAY BE TOO DRY TO SUPPORT PRECIP...IN SPITE OF DECENT MID LEVEL LIFT. LARGE SURFACE HIGH BUILD OVER THE NERN CONUS WITH EASTERLY FLOW STRENGTHENING OVER FL EARLY NEXT WEEK. TEMPS NEAR TO SLIGHTLY BELOW NORMAL. && .AVIATION...NOT LOOKING AS FAVORABLE FOR WIDESPREAD STRATUS/FOG DEVELOPMENT THROUGH EARLY THIS MORNING...BUT SHOULD STILL SEE A FEW LOCATIONS WHERE TEMPO IFR/MVFR CONDS OCCUR THROUGH 13Z. ISO/SCT SHOWERS AND A FEW STORMS WILL BE POSSIBLE INTO THE AFTERNOON... MAINLY OVER THE INTERIOR...BUT RAIN CHANCES REMAIN LOW ENOUGH TO ONLY INCLUDE VCSH IN THE TAFS FOR NOW. && .MARINE... TODAY/TONIGHT...QUASI-STATIONARY FRONT WILL EXIST NEAR TO JUST NORTH OF THE VOLUSIA COUNTY WATERS TODAY INTO TONIGHT. RELATIVELY LIGHT AND VARIABLE WINDS THIS MORNING WILL BECOME ONSHORE AND THEN SWITCH TO THE SOUTH TONIGHT. SEAS WILL RANGE FROM 2-3 FEET. TUE-FRI...LIGHT OFFSHORE PRE-FRONTAL WINDS WILL INCREASE OUT OF THE NORTH IMMEDIATELY BEHIND THE COLD FRONT WED AND NE WED NIGHT. WINDS SLACKEN AND VEER A TAD ON THU BEFORE REINFORCING HIGH PRES AND ASCD NE WIND SURGE PUSH SEAS BACK UP ON FRIDAY. CONDITIONS OVER THE GULF STREAM WILL BE FAIRLY CHOPPY...ESPECIALLY WED AND FRI..GIVEN THE PREVAILING N-NE WIND FLOW. && .PRELIMINARY POINT TEMPS/POPS... DAB 84 70 82 68 / 20 20 50 50 MCO 88 71 86 70 / 30 20 40 50 MLB 87 72 85 71 / 20 20 40 50 VRB 88 72 88 70 / 20 20 40 40 LEE 88 71 85 68 / 30 20 40 50 SFB 87 71 86 69 / 30 20 50 50 ORL 88 72 86 70 / 30 20 40 50 FPR 88 71 87 70 / 20 20 40 40 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && $$ SHORT TERM/AVIATION...WEITLICH LONG TERM/IMPACT WX....CRISTALDI
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
257 AM EDT Mon Oct 21 2013 .NEAR TERM [Today]... Based on objective RUC analysis early this morning, there exists a considerable theta-e gradient in the 900-700mb layer roughly from buoy 42039, to TLH, to VLD. The air mass to the southeast of this boundary is fairly moist, with mixing ratios in the same layer about +1 to +2 standard deviations above normal. The combination of the low-level theta-e gradient bisecting our forecast area, and the anomalously moist air mass over the southeast half of the area should provide enough impetus for isolated showers today along and southeast of the aforementioned line. This is supported by CAM guidance, with a variety of hi-res models showing a similar scenario. The 03-04z runs of the HRRR even show some slow-moving thunderstorms near Apalachicola that produce over 1 inch of rain. That may not be the most likely scenario, but we did shift some of the 20-30% PoPs that had previously only been over the water into some of the coastal counties. Most areas should see at least some filtered sunshine today, with the result being highs near normal. && .SHORT TERM [Tonight Through Wednesday]... While we see decent agreement among the various models in their handling of large scale upper levels features over the next 48 hours, there remain differences in the surface response which will have an impact on the PoP forecast, mainly for Tuesday and Tuesday night. The NAM and GFS continue to be drier than the 12 UTC Euro, although the GFS has trended wetter. The Euro appears to have a better handle on the short wave over northern Mexico and we therefore favor its more enhanced QPF forecast. We continue to use a blend of guidance for the sensible weather, but are mixing in a much larger percentage of the ECMWF solution. This brings slight chance PoPs to the area late tonight. Highest PoPs will be on Tuesday and we have raised them to likely across our FL Big Bend and adjacent zones, tapering off to the northwest. Chance PoPs will then linger into Tuesday night with precip ending from northwest to southeast early Wednesday morning as the latest in a series of progressively stronger cold fronts pushes through. This front will coolest airmass of the season to the region (see below). && .LONG TERM [Wednesday Night through Sunday]... The upper level synoptic pattern will continue to stay in place during the long term period. High pressure ridging will sit over the west coast while a trough hangs over the eastern CONUS. The trough will de-amplify early in the period as a wave of energy ejects to the northeast, but will likely deepen again towards the end of the period, as another wave of energy swings through the trough. With a cool, dry air mass in place, rain chances will be low through the period (less than 20%) and temperatures will be noticeably cooler with highs in the upper 60s to mid 70s and lows in the 40s to around 50. && .AVIATION... [Through 06 UTC Tuesday] Much of the TAF period will be dominated by VFR ceilings at all terminals. However, there could be some MVFR CIGS at TLH and VLD near a region of greater low-level moisture around sunrise. This would be most likely after 09 UTC, and prior to 15 UTC. && .MARINE... Winds and seas will remain relatively low over the marine area until a strong cold front crosses the waters Wednesday morning. Offshore winds behind this front will increase to cautionary or marginal advisory levels from early Wednesday into midday Thursday. Moderate northwest flow will then persist into Friday. && .FIRE WEATHER... RH will remain relatively high for the next couple days before a reinforcing cold front arrives. Much drier air is expected for the latter half of the week, from Wednesday to Friday at least. Despite the drier air, the current forecast would probably make red flag conditions unlikely. However, there could be an increased fire danger by late in the week. && .HYDROLOGY... Despite chances for showers and isolated thunderstorms through Tuesday night, rainfall amounts are not expected to be high enough to cause significant rises on area rivers or any other flooding concerns. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 82 64 80 58 78 / 10 20 60 40 10 Panama City 80 65 81 60 79 / 10 20 50 30 10 Dothan 77 57 81 51 74 / 10 20 40 20 0 Albany 78 60 81 52 76 / 10 20 40 20 0 Valdosta 79 62 78 58 76 / 10 20 60 40 10 Cross City 84 67 79 63 79 / 20 20 60 40 20 Apalachicola 81 66 79 62 78 / 20 20 60 40 10 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ Near Term/Aviation/Fire Weather...Lamers Long Term...Moore Rest of Discussion...Wool
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
232 PM EDT MON OCT 21 2013 ...QUICK SHOT OF RAIN TUESDAY BEFORE COLDER AIR ARRIVES... .SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... LATEST SURFACE ANALYSIS OF THE SOUTHEAST STATES SHOWS HIGH PRESSURE RIDGE REMAINS IN CONTROL BUT INFLUENCE IS WEAKENING. THIS IS DUE TO THE APPROACH OF AN UPPER LEVEL TROUGH WHICH RUC ANALYSIS HAS SITUATED FROM EASTERN ILLINOIS THROUGH MISSOURI AND KANSAS AS WELL AS ADDITIONAL RIPPLES OF UPPER LEVEL ENERGY CLOSER TO HOME EMBEDDED IN BROADER TROUGH REGIME. AS FAR AS THE SENSIBLE WEATHER THIS HAS PRODUCED AT THE SURFACE...PRETTY MUCH A MIXED BAG WITH LOW CLOUDS IN VICINITY OF RIDGE AXIS AROUND ATHENS JUST STARTING TO BREAK UP AND A MOSTLY SUNNY DAY ELSEWHERE WHICH IS QUICKLY GIVING WAY TO INCREASED CIRRUS IN SW FLOW ALOFT. SOME LIGHT RETURNS FORM THIS ON RADAR FOR SOUTHERN SECTIONS BUT NO EVIDENCE ANY OF THIS IS REACHING THE GROUND JUST YET. FOR TONIGHT...GULF COAST WAVE AT THE UPPER LEVELS WILL MOVE INTO SOUTH GEORGIA THIS EVENING ALLOWING FOR INCREASED LIFT AND MOISTURE BOTH AT THE MID LEVELS AND EVENTUALLY LOW LEVELS BY DAYBREAK. IN FACT...MODELS INDICATE LOW CLOUDS REDEVLOPING ACROSS THE SE ZONES WITH SOME POTENTIAL FOR REDUCED VSBY AS WELL PRIOR TO DAYBREAK. EXPECT THICKENING CLOUD DECK AND AFOREMENTIONED LIFT TO RESULT IN -RA WITH LOW END CHANCE ADVERTISED FOR NOW. THIS MAY PROVE TO BE TOO LOW GIVEN THE AMOUNT OF OMEGA INDICATED BY THE MODELS BUT HAVE AT LEAST RAMPED UP SOME 10 TO 20 PERCENT ABOVE GUIDANCE. SAME HOLDS TRUE FOR TUESDAY AS GUIDANCE POPS LOOK MUCH TOO LOW FOR THE AMOUNT OF MOISTURE AND LIFT INDICATED BY THE MODELS...ESPECIALLY THE NAM12. SETUP LOOKS AN AWFUL LOT LIKE THIS PAST SATURDAY WHEN GUIDANCE HAD NO CLUE AND RAIN WAS MUCH MORE WIDESPREAD THAN EXPECTED. WITH SECONDARY SHOT OF ENERGY COMING ACROSS LATE IN THE DAY...FEEL LOW END CHANCE POPS AT LEAST ARE WARRANTED AND THESE MAY NEED TO BE INCREASED FURTHER IF TRENDS CONTINUE. ALSO WENT ON THE LOW SIDE OF GUIDANCE FOR TUE MAX TEMPS BASED ON MORE PRECIP AND CLOUD COVER. DEESE .LONG TERM /WEDNESDAY THROUGH MONDAY/... VERY LITTLE CHANGES NEEDED TO THE EXTENDED FORECAST. BY WED MORNING THE MAIN FRONTAL BOUNDARY WILL HAVE MOVED OFF THE GA/SC COAST WITH HIGH PRESSURE BUILDING INTO THE REGION FROM THE CENTRAL PLAINS. A COOLER AIRMASS WILL MOVE IN WITH THIS RIDGE AS WE WILL SE SOME OF THE COOLEST TEMPS SO FAR THIS SEASON. LOW TEMPS THU MORNING EXPECTED IN THE 30S AND 40S WITH HIGH TEMPS ONLY GETTING UP INTO THE 60S THU. THIS COOL AIR REMAINS OVER THE REGION THROUGH THE END OF THE WEEK AND EVEN GETS REINFORCED FRI/SAT AS ANOTHER STRONGER RIDGE MOVES IN BEHIND A DRY COLD FRONT FROM THE NORTHERN PLAINS. SOME AREAS ACROSS EXTREME N GA WILL SE BELOW FREEZING TEMPS SAT MORNING. TEMPS WILL BEGIN TO REBOUND SUN/MON WILL SEE MAINLY BELOW SEASONAL NORMS WED THROUGH SAT. NO PRECIP EXPECTED THIS WEEK. 01 && .AVIATION... 18Z UPDATE... PERSISTENT PATCH OF LOW CLOUDS OVER NORTHEAST GEORGIA INCLUDING AHN FINALLY STARTING TO BREAK UP WITH JUST A SCT VFR DECK FOR MOST OTHER TAF SITES. SHOULD SEE LOW CLOUDS DEVELOP AGAIN TONIGHT AND ENCROACH UPON THE SOUTHEAST SECTIONS TONIGHT WITH MCN POSSIBLY SEEING REDUCED CIGS AND VSBY PRIOR TO DAYBREAK. EXPECTING LOWERING CIGS ELSEWHERE AS WELL BUT SHOULD REMAIN VFR THROUGH THE PERIOD. HAVE INCREASED RAIN CHANCES FOR TUE AFTERNOON BUT NOT HIGH ENOUGH JUST YET FOR INCLUSION IN TAF. //ATL CONFIDENCE...18Z UPDATE... MEDIUM ON CIGS TONIGHT. HIGH REMAINING ELEMENTS. DEESE && .PRELIMINARY POINT TEMPS/POPS... ATHENS 54 72 50 65 / 5 30 20 0 ATLANTA 55 70 49 61 / 5 30 20 0 BLAIRSVILLE 45 67 42 54 / 5 30 20 5 CARTERSVILLE 47 70 45 59 / 5 30 10 0 COLUMBUS 59 77 54 69 / 5 20 20 0 GAINESVILLE 53 69 49 60 / 5 30 20 0 MACON 57 75 49 70 / 10 30 20 0 ROME 46 70 44 60 / 5 30 10 5 PEACHTREE CITY 50 72 49 63 / 5 20 20 0 VIDALIA 63 75 55 74 / 30 40 30 0 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DEESE LONG TERM....01 AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS CARIBOU ME
942 PM EDT TUE OCT 22 2013 .SYNOPSIS... A COLD FRONT WILL PUSH EAST OF THE AREA TONIGHT THEN A SMALL AREA OF LOW PRESSURE WILL SLIDE SOUTH OF THE REGION ON WEDNESDAY. A LARGE TROUGH OF LOW PRESSURE WILL BUILD INTO THE EAST THURSDAY INTO FRIDAY AS CHILLY AIR PUSHES DOWN FROM CANADA. && .NEAR TERM /THROUGH WEDNESDAY/... 941 PM UPDATE...A STRONG COLD FRONT BISECTS THE SOUTHEAST THIRD OF THE CWA AS OF 930 PM/0130Z. A LINE OF SHOWERS WITH THE FRONT EXTEND FROM JUST SOUTH OF HOULTON TO THE PENOBSCOT BAY. THE LAST OF THE SHOWERS SHOULD CLEAR WASHINGTON COUNTY BETWEEN MIDNIGHT AND 1 AM. BRIEF GUSTY WIND WILL LIKELY CONTINUE TO ACCOMPANY THE FRONT WITH A GUSTS TO AROUND 35 MPH POSSIBLE DURING THE FROPA. THE HRRR CONTINUES TO HAVE A VERY GOOD HANDLE ON THE AREA OF SHOWERS THIS EVENING. WILL UPDATE THE POP AND WIND GRIDS TO MATCH THE CURRENT AND EXPECTED CONDITIONS OVER THE NEXT FEW HOURS. OTHERWISE...NO SIGNIFICANT CHANGES ARE PLANNED FOR THIS UPDATE. 610 PM UPDATE...LOW PRES JUST EAST OF JAMES BAY WILL REMAIN QUASI-STATIONARY TONIGHT AND CONTINUE TO DEEPEN TO AROUND 985 MB BY 12Z WED. A PRE-FRONTAL TROUGH STRETCHES FROM ERN AROOSTOOK COUNTY TO NEAR BANGOR AT 22Z. THERE IS A LINE OF SHOWERS ASSOCIATED WITH THIS TROUGH. THERE IS A SECOND LINE OF SHOWERS WHICH ARE ASSOCIATED WITH A STRONG COLD THAT EXTENDS FROM AROUND FT KENT TO GREENVILLE. THIS FRONT WILL SWEEP ACROSS THE REMAINDER OF THE CWA THIS EVENING LIKELY MERGING WITH THE PRE-FRONTAL TROUGH. THE LAST OF THE SHOWERS SHOULD EXIT SOUTHEAST WASHINGTON COUNTY BY AROUND MIDNIGHT. IN THE WAKE OF THE FRONT A MUCH COLDER AIR MASS WILL SPREAD ACROSS THE REGION OVERNIGHT. MADE SOME TWEAKS TO POP/WX GRIDS BASED ON THE LATEST RADAR RETURNS. ALSO REMOVED THE MENTION OF THUNDER FOR THIS EVENING AS THERE HAVE NOT BEEN ANY CLOUD TO GROUND STRIKES NOR ANY IN CLOUD LIGHTNING. PREVIOUS DISCUSSION... AREA OF SHOWERS SETTING UP AHEAD OF THE APCHG COLD FRONT PER THE 18Z RADAR TREND. 18Z SFC ANALYSIS SHOWS A PRE- FRONTAL TROF OUR AHEAD OF THE COLD FRONT W/THE SHOWERS ALIGNED W/THE BOUNDARY. THE LATEST HRRR WAS DOING QUITE WELL W/THE PLACEMENT AND MOVEMENT OF THE PRECIP SHIELD. LAPS SOUNDINGS SHOWED SOME DESTABILIZATION MAINLY ACROSS THE CENTRAL HIGHLANDS AND INTERIOR DOWNEAST WHERE SOME HEATING AND THE BEST 0-6KM SHEAR EXISTS. CONTINUED TO CARRY ISOLD TSTMS IN THESE AREAS THROUGH 00Z. OTRW, SHOWERS AND GUSTY WINDS OF UP TO 35 MPH AREA POSSIBLE. LATEST RADAR VELOCITY DID SHOW 40 KTS AT 6K FT ACROSS THE CENTRAL HIGHLANDS AT 18Z. TEMPERATURES ARE PEAKED AND NOW WILL BEGIN TO FALL BACK AFTER 00Z WHEN THE COLD FRONT ARRIVES. SHOWERS WILL BE INTO NEW BRUNSWICK BY 02Z OR SO AND THEN PARTIAL CLEARING WILL BEGIN LATER THIS EVENING INTO THE OVERNIGHT HOURS. CAA WILL BRING BREEZY CONDITIONS FOR A WHILE UP THROUGH 06Z AND THEN WINDS WILL DROP OFF AS THE GRADIENT LOOSENS. COLD AIR TO ARRIVE BY WEDNESDAY MORNING W/READINGS BY 7 AM IN THE UPPER 20S TO AROUND 30 ACROSS THE NORTH AND WEST AND LOW/MID 30S INTERIOR DOWNEAST AND THE COAST. COLLABORATED W/NERFC AND LOWERED QPF AMOUNTS TO 0.15-0.30 ACROSS THE NORTHERN 1/2 OF THE CWA W/0.10 OR LESS FOR THE CENTRAL HIGHLANDS AND INTERIOR DOWNEAST. A CHILLY DAY ON WEDNESDAY W/SOME BRIEF RIDGING AND SUNSHINE. IT WILL FEEL SOMEWHAT LIKE A SHOCK TO THE SYSTEM AS DAYTIME HIGHS ARE EXPECTED TO BE IN THE UPPER 40S TO AROUND 50 NORTH AND WEST TO LOWER 50S DOWNEAST. DECIDED ON THE ECMWFMOS/GMOS BLEND FOR TEMPERATURES. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... A DEEP TROUGH MOVING INTO THE EAST WILL USHER IN SOME VERY CHILLY AIR FOR THE LATTER PART OF THIS WEEK. A SMALL WAVE OF LOW PRESSURE TRACKING OFF THE MID ATLANTIC COAST AND SLIDING WELL SOUTH OF THE REGION MAY BRING SOME LIGHT RAIN TO DOWNEAST LOCATIONS EARLY WEDNESDAY EVENING. OTHERWISE, WEDNESDAY NIGHT WILL BE PARTLY CLOUDY AND BECOMING BREEZY AS THE GRADIENT SOUTH OF A LARGE LOW PRESSURE SYSTEM MOVING INTO EASTERN CANADA BEGINS TO EFFECT THE REGION. THIS WILL GIVE WAY TO A WINDY AND CHILLY DAY ON THURSDAY AS COLD AIR PULLING AROUND THE LOW FLOWS INTO THE STATE. SKIES WILL RANGE FROM PARTLY CLOUDY DOWNEAST TO OVERCAST IN STRATOCUMULUS CLOUDS ACROSS THE NORTH AND SOME LIGHT RAIN, OR POSSIBLY SNOW SHOWERS, MAY AFFECT NORTHERN AREAS ESPECIALLY OVER HIGHER ELEVATIONS. BREEZY AND CHILLY CONDITIONS WITH A MOSTLY CLOUDY SKY NORTH AND PARTIAL CLOUDINESS DOWNEAST WILL CONTINUE THURSDAY NIGHT INTO FRIDAY. SOME PATCHY LIGHT SHOWERS OR FLURRIES ARE POSSIBLE IN THE HIGHER ELEVATIONS IN THE WEST THURSDAY NIGHT OR FRIDAY. OTHERWISE, MAINLY DRY WEATHER WILL CONTINUE OVER THE AREA INTO FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A SHORTWAVE CASCADING INTO THE TROUGH FRIDAY NIGHT WILL DEVELOP LOW PRESSURE IN THE GREAT LAKES ON SATURDAY. CHILLY AIR WILL BE IN PLACE SATURDAY INTO SATURDAY EVENING AS THIS LOW APPROACHES WITH INCREASING CLOUDS. PRECIPITATION WILL SPREAD ACROSS THE REGION SATURDAY EVENING. CURRENT GUIDANCE INCLUDING THE GFS AND ECMWF ARE INDICATING THE AIR WILL LIKELY BE COLD ENOUGH TO SUPPORT SOME WET SNOW ACROSS THE NORTH AS THE PRECIPITATION MOVES IN SATURDAY EVENING. THE ECMWF HAS LOW LEVEL CRITICAL THICKNESSES BELOW 1300 AT 1000-850 MB, COLD ENOUGH TO SUPPORT SNOW, ACROSS THE NORTHERN HALF OT THE STATE SATURDAY EVENING. THE GFS HAS THE NORTHERN THIRD OF THE STATE COLD ENOUGH FOR SNOW. ALL OF THE GFS ENSEMBLE MEMBERS SUPPORT THICKNESSES COLD ENOUGH FOR SNOW OVER THE NORTH. THE CANADIAN MODEL, HOWEVER, INDICATES THICKNESSES WILL BE TOO WARM FOR SNOW. THE AIR IS EXPECTED TO WARM A BIT LATE SATURDAY NIGHT INTO SUNDAY MORNING AS THE LOW CENTER TRACKS ACROSS THE NORTHERN PART OF THE STATE SO ANY SNOW WOULD LIKELY TURN OVER TO RAIN. AN INCH OR TWO OF SNOW MAY FALL ACROSS THE NORTHERN PART OF THE STATE BEFORE THE CHANGE OVER WITH THE GREATEST CHANCES FOR SOME ACCUMULATION OVER ELEVATIONS ABOVE 700 FT. PRECIPITATION WILL END SUNDAY MORNING. ANOTHER SURGE OF CHILLY AIR WILL FOLLOW THE SYSTEM EARLY NEXT WEEK AS HIGH PRESSURE BUILDS IN FROM CANADA. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: A BRIEF PERIOD OF MVFR THIS EVENING W/THE COLD FROPA AND THEN VFR WEDNESDAY. SHORT TERM: A PERIOD OF MVFR POSSIBLE WED EVENING AT KBHB AND POSSIBLY KBGR WITH CONDITIONS TO IMPROVE TO VFR LATER WEDNESDAY NIGHT. VFR THURSDAY WITH CONDITIONS TO POSSIBLY LOWER TO MVFR IN STRATOCUMULUS CLOUDS ACROSS THE NORTH LATE THURSDAY INTO THURSDAY NIGHT AND REMAIN VFR DOWNEAST. VFR CONDITIONS ARE EXPECTED FRIDAY INTO SATURDAY. CONDITIONS WILL THEN LOWER TO IFR IN PRECIPITATION (RAIN AND SNOW) SAT NIGHT. && .MARINE... NEAR TERM: SEAS ARE 4 FT AT THE ERN MAINE SHELF AS OF 9 PM EDT. THE WIND AT THE ERN ME SHELF HAS BEEN LESS THAN 10 KNOTS OVER THE PAST SEVERAL HOURS. WILL CANCEL THE SCA WITH THIS UPDATE. A BRIEF WIND GUSTS MAY ACCOMPANY THE WIND SHIFT WITH THE FROPA OVER THE NEXT FEW HOURS...BUT ANY GUSTS WILL BE VERY SHORT LIVED. SHORT TERM: A STRONG SCA OR POSSIBLY A GALE WILL BE NEEDED FOR GUSTY WEST WINDS ON THURSDAY. AN SCA WILL LIKELY BE NEEDED THURSDAY NIGHT. WINDS SHOULD THEN BE BELOW SCA FRIDAY AND SATURDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...CB/HEWITT SHORT TERM...BLOOMER LONG TERM...BLOOMER AVIATION...CB/HEWITT/BLOOMER MARINE...CB/HEWITT/BLOOMER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
122 PM EDT MON OCT 21 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 537 AM EDT MON OCT 21 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE INTO THE PACIFIC NW AND A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND EAST CONUS. A MID LEVEL LOW WAS LOCATED NEAR KINL. A SHORTWAVE TROUGH THAT BROUGHT THE AREA OF RAIN/SNOW THROUGH UPPER MI WAS LIFTING TO THE ENE THROUGH CNTRL UPPER MI. AT THE SFC...LOW PRES WAS LOCATED NEAR WHITE FISH BAY. A TROUGH EXTENDED TO THE NW THROUGH CNTRL LAKE SUPERIOR AND INTO SRN MANITOBA. RADAR INDICATED THAT THE MAIN AREA OF PCPN HAD MOVED INTO ERN LAKE SUPERIOR WITH MAINLY FLURRIES/DRIZZLE TO THE WEST AS 850-500 QVECTOR DIV MOVES IN BEHIND THE SHRTWV. TODAY...CONVERGENT LOW LEVEL WRLY WINDS ACROSS LAKE SUPERIOR WITH 850 MB TEMPS FALLING FROM -5C TO -8C AND ABUNDANT MOISTURE BELOW 700 MB SHOULD CONTINUE TO SUPPORT SCT/NMRS SNOW SHOWERS INTO NW UPPER MI THAT WILL BE MIXED WITH RAIN NEAR THE SHORELINE. THE HIGH RES MODELS SUGGEST THAT THE SNOW SHOWERS WILL BE MOST PROMINENT IN THE AREA FROM NEAR ONTONAGON AND ROCKLAND TO TWIN LAKES AND PELKIE. OTHERWISE...MAINLY DRY WEATHER IS EXPECTED ACROSS THE REST OF THE CWA WITH SYNOPTIC SCALE SUBSIDENCE TAKING OVER. IT WILL ALSO FEEL COLDER WITH GUSTY WEST WINDS AND HIGHS FROM THE MID AND UPPER 30S WEST TO THE MID 40S EAST. TONIGHT...EXPECT THE SNOW SHOWERS OVER THE WEST TO INCREASE IN COVERAGE AND INTENSITY AS THE SFC TROUGH EDGES INTO THE AREA. THE ENHANCED LOW LEVEL CONV WITH THIS FEATURE COMBINED WITH 850 MB TEMPS AROUND -7C AND THE PROXIMITY OF THE MID LEVEL LOW WILL LEAD TO LAKE INDUCED CAPE VALUES TO AROUND 500 J/KG. A PERIOD OF MODERATE TO HEAVY SNOW SHOULD SPREAD INTO NW UPPER MI THIS EVENING AND SAG INTO IWD BY LATE EVENING AND INTO MARQUETTE COUNTY AFT 06Z. A TRANSITION TO WIND PARALLEL NNW FLOW LAKE ENHANCED SNOW IS THEN EXPECTED FOLLOWING PASSAGE OF THE TROUGH. OVERALL SNOW TOTALS IN THE 1 TO 4 INCH RANGE ARE EXPECTED WITH THE GREATEST AMOUNTS IN THE HIGHER TERRAIN FROM TWIN LAKE SOUTHWARD AND OVER THE HURON MOUNTAINS. SNOW/WATER RATIOS SHOULD REMAIN RELATIVELY LOW...AOB 10/1...AS THE STRONGEST UPWARD MOTION REMAINS BELOW THE DGZ AND THE LOWER LEVELS REMAIN NEAR 0C. AN ADVISORY WAS POSTED FOR THE WRN HALF OF THE CWA ADJOINING LAKE SUPERIOR. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 350 AM EDT MON OCT 21 2013 A LARGE UPPER TROUGH WILL BE OVER THE GREAT LAKES REGION FOR THIS WORK WEEK AND LEAD TO BELOW NORMAL TEMPERATURES FOR UPPER MICHIGAN. THIS COLD AIR WILL ALSO LEAD TO LAKE EFFECT SNOW NEAR LAKE SUPERIOR. UNCERTAINTY GROWS HEADING INTO THE WEEKEND ON HOW THE MODELS HANDLE THE UPPER TROUGH SHIFTING EAST OR RE-AMPLIFYING OVER THE GREAT LAKES. FOR TUESDAY...THE SURFACE TROUGH THAT WILL BE SWEEPING EAST ACROSS UPPER MICHIGAN TONIGHT WILL QUICKLY EXIT EASTERN UPPER MICHIGAN ON TUESDAY MORNING. PRECIPITATION WILL BE ONGOING OVER MUCH OF UPPER MICHIGAN...ESPECIALLY NEAR LAKE SUPERIOR WITH THE NORTHWEST LAKE ENHANCED FLOW. MODELS ARE CONTINUING TO SHOW MOISTURE ABOVE 850MB TO QUICKLY DIMINISH FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA THROUGH THE DAY ON TUESDAY. THINK THIS DRY AIR ENTRAINMENT WILL REALLY PUT A CRIMP ON THE SNOWFALL OVER MUCH OF THE CWA EVEN WITH THE DELTA-T VALUES AROUND 18 AND OVER LAKE INSTABILITY IS AROUND 300-500 J/KG. THUS...WILL SHOW THE HIGHEST POPS TO START TUESDAY AND QUICKLY DIMINISH VALUES THROUGH THE AFTERNOON HOURS. HELD ON TO THE HIGHEST POPS OVER THE EAST SINCE THERE MAY BE ENOUGH TIME OVER THE LAKE TO KEEP SOME SHOWERS AROUND THROUGH THE DAY. EVEN THOUGH THE DEEPER MOISTURE IS LACKING...WILL SHOW MOSTLY CLOUDY SKIES FOR THE NORTHWEST WIND FAVORED LOCATIONS INTO THE AFTERNOON. A WEAK SHORTWAVE SLIDING THROUGH THE AREA ON TUESDAY EVENING WILL BRING INCREASING LOW LEVEL MOISTURE ACROSS THE LAKE TUESDAY NIGHT AND THAT WILL CONTINUE INTO WEDNESDAY. 850MB TEMPS ARE STILL AROUND -7C TUESDAY NIGHT INTO WEDNESDAY...SO THERE IS PLENTY OF OVER THE LAKE INSTABILITY TO SUPPORT LAKE EFFECT SNOWFALL IN THE NORTHWEST WIND FAVORED LOCATIONS. EQUILIBRIUM LEVELS AROUND 12KFT WILL SUPPORT DEEP CLOUD DEPTHS FOR MODERATE LAKE EFFECT SNOW POTENTIAL. SNOWFALL AMOUNTS WILL LIKELY BE LIMITED BY SNOW RATIOS BEING AROUND 10-1 DUE TO ONLY THE TOP 5KFT OF THE CLOUD WITHIN THE DGZ AND THE BEST LAKE FORCING BELOW THAT. THEREFORE...SHOULD SEE SOME CLUMPING OF THE FLAKES TO SUPPORT THE MORE SYSTEM SNOW LIKE SLR VALUES...WHICH WILL CUT SNOWFALL AMOUNTS IN HALF FROM WHAT IS TRADITIONALLY SEEN DURING PURE LES EVENTS. IN ADDITION...WITH DAYTIME TEMPERATURES TRYING TO RISE INTO THE UPPER 30S OVER THE EAST...IT TRENDS AWAY FROM THE LOWER 30S GENERALLY NEEDED FOR SNOW ACCUMULATION. THAT FACTOR IS ALSO INFLUENCED BY THE NORTHWEST WINDS COMING OFF LAKE SUPERIOR WITH IT/S SURFACE TEMPS AROUND 50 DEGREES...WHICH DOES RAISE THE WETBULB VALUES TO HAVE SOME RAIN MIXING IN DURING THE DAY WEDNESDAY. THINKING THE BEST OPPORTUNITY FOR MEASUREABLE SNOW WOULD BE UNDER THE HEAVIEST BANDS AND LATE TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THEREFORE...HAVE MOST NW WIND LOCATIONS ONLY SEEING AROUND AN INCH OF SNOW THROUGH WEDNESDAY. AS WE GET A LITTLE CLOSER WE SHOULD BE ABLE TO PIN DOWN ANY STRONGER BANDS...WHICH WOULD LOWER TEMPS AND INCREASE SNOWFALL ACCUMULATIONS. SINCE THE AREA WILL CONTINUE TO BE BETWEEN THE LOW JUST EAST OF JAMES BAY AND A SERIES OF HIGHS SLIDING SOUTHEAST THROUGH THE NORTHERN PLAINS...EXPECT THE NORTHWEST WINDS TO CONTINUE THROUGH THURSDAY NIGHT. 850MB TEMPS LOOK LIKE THERE IS LITTLE VARIABILITY DURING THAT PERIOD AND WITH MODELS CONTINUING TO SHOW ENOUGH MOISTURE IN THE LOWER LEVELS...WILL HIGHLIGHT LIKELY POPS IN THE NORMAL NORTHWEST WIND LOCATIONS THROUGH THE TIME PERIOD. ALTHOUGH ACCUMULATIONS WON/T BE LARGE...STILL THINK THERE WILL BE SOME AREAS IN THE WEST AND EAST OF MUNISING THAT WILL HAVE A FEW INCHES OF SNOW ON THE GROUND BY FRIDAY. BEST OPPORTUNITY FOR ACCUMULATIONS WILL BE OVER THE WEST...WITH THE EXISTING SNOW ON THE GROUND FROM TONIGHT. MODELS REALLY DIFFER ON THE HANDLING OF A SHORTWAVE DIVING SOUTHEAST TOWARDS THE GREAT LAKES REGION ON FRIDAY AND ACROSS THE AREA ON SATURDAY OR SUNDAY. THIS SHORTWAVE HAS A LONG JOURNEY AHEAD OF IT (CURRENTLY NORTH OF HAWAII) AND NEEDS TO ROUND THE RIDGE OVER THE WEST AND POTENTIALLY MERGE WITH THE ANOTHER WAVE IN NORTHWEST CANADA. WITH THAT LONG OF A DISTANCE TO TRAVEL...IT/S NOT SURPRISING THAT THERE ARE DIFFERENCES IN THE GEM/ECMWF/GFS ON THE SHORTWAVE AND POTENTIAL CLIPPER SYSTEM MOVING THROUGH THE AREA. 12Z GEM/GFS WERE FAIRLY SIMILAR ON THE WAVE AND CLIPPER MOVING THROUGH ON FRIDAY NIGHT INTO SATURDAY MORNING...WHILE THE 12Z ECMWF WAS MUCH SLOWER AND KEEPS THE CLIPPER NORTH OF THE AREA (MOVING THROUGH NORTHERN ONTARIO ON SATURDAY NIGHT). 00Z RUNS HAVE FLIPPED THE GEM/ECMWF IDEAS WITH THE 00Z GFS STAYING SIMILAR. THESE DIFFERENCES LEAD TO LITTLE OR NO CONFIDENCE FOR THAT TIME FRAME OTHER THAN THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE. USING A GENERAL CONSENSUS OF THE MODELS GIVES LOW END CHANCE POPS FOR THE WEEKEND. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 122 PM EDT MON OCT 21 2013 GUSTY WEST WINDS WILL CONTINUE THIS AFTERNOON AT ALL SITES THIS AFTERNOON WITH TRANSIENT LAKE EFFECT SNOW SHOWERS AND MVFR CONDITIONS EXCEPT AT SAW WHICH WILL HAVE A WEST DOWNSLOPE WIND. WITH ANOTHER DISTURBANCE COMING IN TONIGHT...LAKE EFFECT SNOW SHOWERS WILL PICK UP IN INTENSITY WITH THE ARRIVAL OF ANOTHER LO PRES TROF THIS EVENING WILL BRING IFR CONDITIONS/SHSN AT IWD/CMX WHICH WILL GRADUALLY DIMINISH LATE TONIGHT AND RETURN TO MVFR THERE. AT SAW...MVFR CONDITIONS WILL MOVE BACK IN THIS EVENING WITH THE TROUGH. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 401 PM EDT SUN OCT 20 2013 A LOW CENTERED OVER MUCH OF MINNESOTA AN NORTHERN IOWA WILL SLIDE ACROSS THE UPPER GREAT LAKES TONIGHT THROUGH EARLY MONDAY. EXPECT THIS LOW TO LIFT SLOWLY INTO QUEBEC MONDAY AFTERNOON WHILE KEEPING A TROUGH OVER THE UPPER GREAT LAKES THROUGH THURSDAY. A PERIOD OF 35KT GUSTS WILL BE POSSIBLE OVER S LAKE SUPERIOR STARTING MID MORNING MONDAY /OUT OF THE W/. A SECOND PUSH OF STRONGER WINDS WILL COME IN AS THE TROUGH OF LOW PRESSURE WRAPS BACK AROUND...WITH A PERIOD OF NW GALES OF 35 TO NEAR 40KTS OVER MAINLY CENTRAL AND E LAKE SUPERIOR MONDAY NIGHT INTO MID TUESDAY. WINDS WILL SLOWLY DIMINISH TUESDAY AFTERNOON...WITH GUSTS LINGERING IN THE 20 TO 30KT RANGE THROUGH THE REST OF THE WORK WEEK. BROAD HIGH PRESSURE OF IS EXPECTED TO BUILD OVER MUCH OF THE PLAINS STATES BY THURSDAY NIGHT AND SPREAD EASTWARD INTO MUCH OF EASTERN CONTINENTAL UNITED STATES...WITH A RIDGE OVER THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 8 AM EDT TUESDAY FOR MIZ002>004-084. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 7 AM CDT TUESDAY FOR MIZ009. WINTER WEATHER ADVISORY FROM 1 AM TO 11 AM EDT TUESDAY FOR MIZ005. LAKE SUPERIOR... GALE WARNING UNTIL 11 AM EDT TUESDAY FOR LSZ265>267. GALE WARNING FROM 8 PM THIS EVENING TO 11 AM EDT TUESDAY FOR LSZ264. GALE WARNING UNTIL 8 AM EDT TUESDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...07 MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 AM EDT MON OCT 21 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 537 AM EDT MON OCT 21 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE INTO THE PACIFIC NW AND A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND EAST CONUS. A MID LEVEL LOW WAS LOCATED NEAR KINL. A SHORTWAVE TROUGH THAT BROUGHT THE AREA OF RAIN/SNOW THROUGH UPPER MI WAS LIFTING TO THE ENE THROUGH CNTRL UPPER MI. AT THE SFC...LOW PRES WAS LOCATED NEAR WHITE FISH BAY. A TROUGH EXTENDED TO THE NW THROUGH CNTRL LAKE SUPERIOR AND INTO SRN MANITOBA. RADAR INDICATED THAT THE MAIN AREA OF PCPN HAD MOVED INTO ERN LAKE SUPERIOR WITH MAINLY FLURRIES/DRIZZLE TO THE WEST AS 850-500 QVECTOR DIV MOVES IN BEHIND THE SHRTWV. TODAY...CONVERGENT LOW LEVEL WRLY WINDS ACROSS LAKE SUPERIOR WITH 850 MB TEMPS FALLING FROM -5C TO -8C AND ABUNDANT MOISTURE BELOW 700 MB SHOULD CONTINUE TO SUPPORT SCT/NMRS SNOW SHOWERS INTO NW UPPER MI THAT WILL BE MIXED WITH RAIN NEAR THE SHORELINE. THE HIGH RES MODELS SUGGEST THAT THE SNOW SHOWERS WILL BE MOST PROMINENT IN THE AREA FROM NEAR ONTONAGON AND ROCKLAND TO TWIN LAKES AND PELKIE. OTHERWISE...MAINLY DRY WEATHER IS EXPECTED ACROSS THE REST OF THE CWA WITH SYNOPTIC SCALE SUBSIDENCE TAKING OVER. IT WILL ALSO FEEL COLDER WITH GUSTY WEST WINDS AND HIGHS FROM THE MID AND UPPER 30S WEST TO THE MID 40S EAST. TONIGHT...EXPECT THE SNOW SHOWERS OVER THE WEST TO INCREASE IN COVERAGE AND INTENSITY AS THE SFC TROUGH EDGES INTO THE AREA. THE ENHANCED LOW LEVEL CONV WITH THIS FEATURE COMBINED WITH 850 MB TEMPS AROUND -7C AND THE PROXIMITY OF THE MID LEVEL LOW WILL LEAD TO LAKE INDUCED CAPE VALUES TO AROUND 500 J/KG. A PERIOD OF MODERATE TO HEAVY SNOW SHOULD SPREAD INTO NW UPPER MI THIS EVENING AND SAG INTO IWD BY LATE EVENING AND INTO MARQUETTE COUNTY AFT 06Z. A TRANSITION TO WIND PARALLEL NNW FLOW LAKE ENHANCED SNOW IS THEN EXPECTED FOLLOWING PASSAGE OF THE TROUGH. OVERALL SNOW TOTALS IN THE 1 TO 4 INCH RANGE ARE EXPECTED WITH THE GREATEST AMOUNTS IN THE HIGHER TERRAIN FROM TWIN LAKE SOUTHWARD AND OVER THE HURON MOUNTAINS. SNOW/WATER RATIOS SHOULD REMAIN RELATIVELY LOW...AOB 10/1...AS THE STRONGEST UPWARD MOTION REMAINS BELOW THE DGZ AND THE LOWER LEVELS REMAIN NEAR 0C. AN ADVISORY WAS POSTED FOR THE WRN HALF OF THE CWA ADJOINING LAKE SUPERIOR. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 350 AM EDT MON OCT 21 2013 A LARGE UPPER TROUGH WILL BE OVER THE GREAT LAKES REGION FOR THIS WORK WEEK AND LEAD TO BELOW NORMAL TEMPERATURES FOR UPPER MICHIGAN. THIS COLD AIR WILL ALSO LEAD TO LAKE EFFECT SNOW NEAR LAKE SUPERIOR. UNCERTAINTY GROWS HEADING INTO THE WEEKEND ON HOW THE MODELS HANDLE THE UPPER TROUGH SHIFTING EAST OR RE-AMPLIFYING OVER THE GREAT LAKES. FOR TUESDAY...THE SURFACE TROUGH THAT WILL BE SWEEPING EAST ACROSS UPPER MICHIGAN TONIGHT WILL QUICKLY EXIT EASTERN UPPER MICHIGAN ON TUESDAY MORNING. PRECIPITATION WILL BE ONGOING OVER MUCH OF UPPER MICHIGAN...ESPECIALLY NEAR LAKE SUPERIOR WITH THE NORTHWEST LAKE ENHANCED FLOW. MODELS ARE CONTINUING TO SHOW MOISTURE ABOVE 850MB TO QUICKLY DIMINISH FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA THROUGH THE DAY ON TUESDAY. THINK THIS DRY AIR ENTRAINMENT WILL REALLY PUT A CRIMP ON THE SNOWFALL OVER MUCH OF THE CWA EVEN WITH THE DELTA-T VALUES AROUND 18 AND OVER LAKE INSTABILITY IS AROUND 300-500 J/KG. THUS...WILL SHOW THE HIGHEST POPS TO START TUESDAY AND QUICKLY DIMINISH VALUES THROUGH THE AFTERNOON HOURS. HELD ON TO THE HIGHEST POPS OVER THE EAST SINCE THERE MAY BE ENOUGH TIME OVER THE LAKE TO KEEP SOME SHOWERS AROUND THROUGH THE DAY. EVEN THOUGH THE DEEPER MOISTURE IS LACKING...WILL SHOW MOSTLY CLOUDY SKIES FOR THE NORTHWEST WIND FAVORED LOCATIONS INTO THE AFTERNOON. A WEAK SHORTWAVE SLIDING THROUGH THE AREA ON TUESDAY EVENING WILL BRING INCREASING LOW LEVEL MOISTURE ACROSS THE LAKE TUESDAY NIGHT AND THAT WILL CONTINUE INTO WEDNESDAY. 850MB TEMPS ARE STILL AROUND -7C TUESDAY NIGHT INTO WEDNESDAY...SO THERE IS PLENTY OF OVER THE LAKE INSTABILITY TO SUPPORT LAKE EFFECT SNOWFALL IN THE NORTHWEST WIND FAVORED LOCATIONS. EQUILIBRIUM LEVELS AROUND 12KFT WILL SUPPORT DEEP CLOUD DEPTHS FOR MODERATE LAKE EFFECT SNOW POTENTIAL. SNOWFALL AMOUNTS WILL LIKELY BE LIMITED BY SNOW RATIOS BEING AROUND 10-1 DUE TO ONLY THE TOP 5KFT OF THE CLOUD WITHIN THE DGZ AND THE BEST LAKE FORCING BELOW THAT. THEREFORE...SHOULD SEE SOME CLUMPING OF THE FLAKES TO SUPPORT THE MORE SYSTEM SNOW LIKE SLR VALUES...WHICH WILL CUT SNOWFALL AMOUNTS IN HALF FROM WHAT IS TRADITIONALLY SEEN DURING PURE LES EVENTS. IN ADDITION...WITH DAYTIME TEMPERATURES TRYING TO RISE INTO THE UPPER 30S OVER THE EAST...IT TRENDS AWAY FROM THE LOWER 30S GENERALLY NEEDED FOR SNOW ACCUMULATION. THAT FACTOR IS ALSO INFLUENCED BY THE NORTHWEST WINDS COMING OFF LAKE SUPERIOR WITH IT/S SURFACE TEMPS AROUND 50 DEGREES...WHICH DOES RAISE THE WETBULB VALUES TO HAVE SOME RAIN MIXING IN DURING THE DAY WEDNESDAY. THINKING THE BEST OPPORTUNITY FOR MEASUREABLE SNOW WOULD BE UNDER THE HEAVIEST BANDS AND LATE TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THEREFORE...HAVE MOST NW WIND LOCATIONS ONLY SEEING AROUND AN INCH OF SNOW THROUGH WEDNESDAY. AS WE GET A LITTLE CLOSER WE SHOULD BE ABLE TO PIN DOWN ANY STRONGER BANDS...WHICH WOULD LOWER TEMPS AND INCREASE SNOWFALL ACCUMULATIONS. SINCE THE AREA WILL CONTINUE TO BE BETWEEN THE LOW JUST EAST OF JAMES BAY AND A SERIES OF HIGHS SLIDING SOUTHEAST THROUGH THE NORTHERN PLAINS...EXPECT THE NORTHWEST WINDS TO CONTINUE THROUGH THURSDAY NIGHT. 850MB TEMPS LOOK LIKE THERE IS LITTLE VARIABILITY DURING THAT PERIOD AND WITH MODELS CONTINUING TO SHOW ENOUGH MOISTURE IN THE LOWER LEVELS...WILL HIGHLIGHT LIKELY POPS IN THE NORMAL NORTHWEST WIND LOCATIONS THROUGH THE TIME PERIOD. ALTHOUGH ACCUMULATIONS WON/T BE LARGE...STILL THINK THERE WILL BE SOME AREAS IN THE WEST AND EAST OF MUNISING THAT WILL HAVE A FEW INCHES OF SNOW ON THE GROUND BY FRIDAY. BEST OPPORTUNITY FOR ACCUMULATIONS WILL BE OVER THE WEST...WITH THE EXISTING SNOW ON THE GROUND FROM TONIGHT. MODELS REALLY DIFFER ON THE HANDLING OF A SHORTWAVE DIVING SOUTHEAST TOWARDS THE GREAT LAKES REGION ON FRIDAY AND ACROSS THE AREA ON SATURDAY OR SUNDAY. THIS SHORTWAVE HAS A LONG JOURNEY AHEAD OF IT (CURRENTLY NORTH OF HAWAII) AND NEEDS TO ROUND THE RIDGE OVER THE WEST AND POTENTIALLY MERGE WITH THE ANOTHER WAVE IN NORTHWEST CANADA. WITH THAT LONG OF A DISTANCE TO TRAVEL...IT/S NOT SURPRISING THAT THERE ARE DIFFERENCES IN THE GEM/ECMWF/GFS ON THE SHORTWAVE AND POTENTIAL CLIPPER SYSTEM MOVING THROUGH THE AREA. 12Z GEM/GFS WERE FAIRLY SIMILAR ON THE WAVE AND CLIPPER MOVING THROUGH ON FRIDAY NIGHT INTO SATURDAY MORNING...WHILE THE 12Z ECMWF WAS MUCH SLOWER AND KEEPS THE CLIPPER NORTH OF THE AREA (MOVING THROUGH NORTHERN ONTARIO ON SATURDAY NIGHT). 00Z RUNS HAVE FLIPPED THE GEM/ECMWF IDEAS WITH THE 00Z GFS STAYING SIMILAR. THESE DIFFERENCES LEAD TO LITTLE OR NO CONFIDENCE FOR THAT TIME FRAME OTHER THAN THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE. USING A GENERAL CONSENSUS OF THE MODELS GIVES LOW END CHANCE POPS FOR THE WEEKEND. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 741 AM EDT MON OCT 21 2013 WITH A DEEPENING LOW INTO ERN LAKE SUEPRIOR...W WINDS WILL BECOME QUITE GUSTY...ESPECIALLY AT THE MORE EXPOSED CMX LOCATION. WITH THE ARRIVAL OF SOMEWHAT DRIER LOW LEVEL AIR...PLAN ON A SLOW IMPROVEMENT TO MVFR DESPITE A PERSISTENT UPSLOPE WIND COMPONENT. SAW SHOULD SEE VFR CIGS IN DOWNSLOPE FLOW. ARRIVAL OF ANOTHER LO PRES TROF THIS EVENING WILL BRING IFR CONDITIONS/SHSN AT IWD/CMX WHICH WILL GRADUALLY DIMINISH LATE TONIGHT. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 401 PM EDT SUN OCT 20 2013 A LOW CENTERED OVER MUCH OF MINNESOTA AN NORTHERN IOWA WILL SLIDE ACROSS THE UPPER GREAT LAKES TONIGHT THROUGH EARLY MONDAY. EXPECT THIS LOW TO LIFT SLOWLY INTO QUEBEC MONDAY AFTERNOON WHILE KEEPING A TROUGH OVER THE UPPER GREAT LAKES THROUGH THURSDAY. A PERIOD OF 35KT GUSTS WILL BE POSSIBLE OVER S LAKE SUPERIOR STARTING MID MORNING MONDAY /OUT OF THE W/. A SECOND PUSH OF STRONGER WINDS WILL COME IN AS THE TROUGH OF LOW PRESSURE WRAPS BACK AROUND...WITH A PERIOD OF NW GALES OF 35 TO NEAR 40KTS OVER MAINLY CENTRAL AND E LAKE SUPERIOR MONDAY NIGHT INTO MID TUESDAY. WINDS WILL SLOWLY DIMINISH TUESDAY AFTERNOON...WITH GUSTS LINGERING IN THE 20 TO 30KT RANGE THROUGH THE REST OF THE WORK WEEK. BROAD HIGH PRESSURE OF IS EXPECTED TO BUILD OVER MUCH OF THE PLAINS STATES BY THURSDAY NIGHT AND SPREAD EASTWARD INTO MUCH OF EASTERN CONTINENTAL UNITED STATES...WITH A RIDGE OVER THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 8 AM EDT TUESDAY FOR MIZ002>004-084. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 7 AM CDT TUESDAY FOR MIZ009. WINTER WEATHER ADVISORY FROM 1 AM TO 11 AM EDT TUESDAY FOR MIZ005. LAKE SUPERIOR... GALE WARNING FROM 11 AM THIS MORNING TO 11 AM EDT TUESDAY FOR LSZ265>267. GALE WARNING FROM 8 PM THIS EVENING TO 11 AM EDT TUESDAY FOR LSZ264. GALE WARNING FROM 11 AM THIS MORNING TO 8 AM EDT TUESDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...JLB MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
538 AM EDT MON OCT 21 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 537 AM EDT MON OCT 21 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE INTO THE PACIFIC NW AND A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND EAST CONUS. A MID LEVEL LOW WAS LOCATED NEAR KINL. A SHORTWAVE TROUGH THAT BROUGHT THE AREA OF RAIN/SNOW THROUGH UPPER MI WAS LIFTING TO THE ENE THROUGH CNTRL UPPER MI. AT THE SFC...LOW PRES WAS LOCATED NEAR WHITE FISH BAY. A TROUGH EXTENDED TO THE NW THROUGH CNTRL LAKE SUPERIOR AND INTO SRN MANITOBA. RADAR INDICATED THAT THE MAIN AREA OF PCPN HAD MOVED INTO ERN LAKE SUPERIOR WITH MAINLY FLURRIES/DRIZZLE TO THE WEST AS 850-500 QVECTOR DIV MOVES IN BEHIND THE SHRTWV. TODAY...CONVERGENT LOW LEVEL WRLY WINDS ACROSS LAKE SUPERIOR WITH 850 MB TEMPS FALLING FROM -5C TO -8C AND ABUNDANT MOISTURE BELOW 700 MB SHOULD CONTINUE TO SUPPORT SCT/NMRS SNOW SHOWERS INTO NW UPPER MI THAT WILL BE MIXED WITH RAIN NEAR THE SHORELINE. THE HIGH RES MODELS SUGGEST THAT THE SNOW SHOWERS WILL BE MOST PROMINENT IN THE AREA FROM NEAR ONTONAGON AND ROCKLAND TO TWIN LAKES AND PELKIE. OTHERWISE...MAINLY DRY WEATHER IS EXPECTED ACROSS THE REST OF THE CWA WITH SYNOPTIC SCALE SUBSIDENCE TAKING OVER. IT WILL ALSO FEEL COLDER WITH GUSTY WEST WINDS AND HIGHS FROM THE MID AND UPPER 30S WEST TO THE MID 40S EAST. TONIGHT...EXPECT THE SNOW SHOWERS OVER THE WEST TO INCREASE IN COVERAGE AND INTENSITY AS THE SFC TROUGH EDGES INTO THE AREA. THE ENHANCED LOW LEVEL CONV WITH THIS FEATURE COMBINED WITH 850 MB TEMPS AROUND -7C AND THE PROXIMITY OF THE MID LEVEL LOW WILL LEAD TO LAKE INDUCED CAPE VALUES TO AROUND 500 J/KG. A PERIOD OF MODERATE TO HEAVY SNOW SHOULD SPREAD INTO NW UPPER MI THIS EVENING AND SAG INTO IWD BY LATE EVENING AND INTO MARQUETTE COUNTY AFT 06Z. A TRANSITION TO WIND PARALLEL NNW FLOW LAKE ENHANCED SNOW IS THEN EXPECTED FOLLOWING PASSAGE OF THE TROUGH. OVERALL SNOW TOTALS IN THE 1 TO 4 INCH RANGE ARE EXPECTED WITH THE GREATEST AMOUNTS IN THE HIGHER TERRAIN FROM TWIN LAKE SOUTHWARD AND OVER THE HURON MOUNTAINS. SNOW/WATER RATIOS SHOULD REMAIN RELATIVELY LOW...AOB 10/1...AS THE STRONGEST UPWARD MOTION REMAINS BELOW THE DGZ AND THE LOWER LEVELS REMAIN NEAR 0C. AN ADVISORY WAS POSTED FOR THE WRN HALF OF THE CWA ADJOINING LAKE SUPERIOR. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 350 AM EDT MON OCT 21 2013 A LARGE UPPER TROUGH WILL BE OVER THE GREAT LAKES REGION FOR THIS WORK WEEK AND LEAD TO BELOW NORMAL TEMPERATURES FOR UPPER MICHIGAN. THIS COLD AIR WILL ALSO LEAD TO LAKE EFFECT SNOW NEAR LAKE SUPERIOR. UNCERTAINTY GROWS HEADING INTO THE WEEKEND ON HOW THE MODELS HANDLE THE UPPER TROUGH SHIFTING EAST OR RE-AMPLIFYING OVER THE GREAT LAKES. FOR TUESDAY...THE SURFACE TROUGH THAT WILL BE SWEEPING EAST ACROSS UPPER MICHIGAN TONIGHT WILL QUICKLY EXIT EASTERN UPPER MICHIGAN ON TUESDAY MORNING. PRECIPITATION WILL BE ONGOING OVER MUCH OF UPPER MICHIGAN...ESPECIALLY NEAR LAKE SUPERIOR WITH THE NORTHWEST LAKE ENHANCED FLOW. MODELS ARE CONTINUING TO SHOW MOISTURE ABOVE 850MB TO QUICKLY DIMINISH FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA THROUGH THE DAY ON TUESDAY. THINK THIS DRY AIR ENTRAINMENT WILL REALLY PUT A CRIMP ON THE SNOWFALL OVER MUCH OF THE CWA EVEN WITH THE DELTA-T VALUES AROUND 18 AND OVER LAKE INSTABILITY IS AROUND 300-500 J/KG. THUS...WILL SHOW THE HIGHEST POPS TO START TUESDAY AND QUICKLY DIMINISH VALUES THROUGH THE AFTERNOON HOURS. HELD ON TO THE HIGHEST POPS OVER THE EAST SINCE THERE MAY BE ENOUGH TIME OVER THE LAKE TO KEEP SOME SHOWERS AROUND THROUGH THE DAY. EVEN THOUGH THE DEEPER MOISTURE IS LACKING...WILL SHOW MOSTLY CLOUDY SKIES FOR THE NORTHWEST WIND FAVORED LOCATIONS INTO THE AFTERNOON. A WEAK SHORTWAVE SLIDING THROUGH THE AREA ON TUESDAY EVENING WILL BRING INCREASING LOW LEVEL MOISTURE ACROSS THE LAKE TUESDAY NIGHT AND THAT WILL CONTINUE INTO WEDNESDAY. 850MB TEMPS ARE STILL AROUND -7C TUESDAY NIGHT INTO WEDNESDAY...SO THERE IS PLENTY OF OVER THE LAKE INSTABILITY TO SUPPORT LAKE EFFECT SNOWFALL IN THE NORTHWEST WIND FAVORED LOCATIONS. EQUILIBRIUM LEVELS AROUND 12KFT WILL SUPPORT DEEP CLOUD DEPTHS FOR MODERATE LAKE EFFECT SNOW POTENTIAL. SNOWFALL AMOUNTS WILL LIKELY BE LIMITED BY SNOW RATIOS BEING AROUND 10-1 DUE TO ONLY THE TOP 5KFT OF THE CLOUD WITHIN THE DGZ AND THE BEST LAKE FORCING BELOW THAT. THEREFORE...SHOULD SEE SOME CLUMPING OF THE FLAKES TO SUPPORT THE MORE SYSTEM SNOW LIKE SLR VALUES...WHICH WILL CUT SNOWFALL AMOUNTS IN HALF FROM WHAT IS TRADITIONALLY SEEN DURING PURE LES EVENTS. IN ADDITION...WITH DAYTIME TEMPERATURES TRYING TO RISE INTO THE UPPER 30S OVER THE EAST...IT TRENDS AWAY FROM THE LOWER 30S GENERALLY NEEDED FOR SNOW ACCUMULATION. THAT FACTOR IS ALSO INFLUENCED BY THE NORTHWEST WINDS COMING OFF LAKE SUPERIOR WITH IT/S SURFACE TEMPS AROUND 50 DEGREES...WHICH DOES RAISE THE WETBULB VALUES TO HAVE SOME RAIN MIXING IN DURING THE DAY WEDNESDAY. THINKING THE BEST OPPORTUNITY FOR MEASUREABLE SNOW WOULD BE UNDER THE HEAVIEST BANDS AND LATE TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THEREFORE...HAVE MOST NW WIND LOCATIONS ONLY SEEING AROUND AN INCH OF SNOW THROUGH WEDNESDAY. AS WE GET A LITTLE CLOSER WE SHOULD BE ABLE TO PIN DOWN ANY STRONGER BANDS...WHICH WOULD LOWER TEMPS AND INCREASE SNOWFALL ACCUMULATIONS. SINCE THE AREA WILL CONTINUE TO BE BETWEEN THE LOW JUST EAST OF JAMES BAY AND A SERIES OF HIGHS SLIDING SOUTHEAST THROUGH THE NORTHERN PLAINS...EXPECT THE NORTHWEST WINDS TO CONTINUE THROUGH THURSDAY NIGHT. 850MB TEMPS LOOK LIKE THERE IS LITTLE VARIABILITY DURING THAT PERIOD AND WITH MODELS CONTINUING TO SHOW ENOUGH MOISTURE IN THE LOWER LEVELS...WILL HIGHLIGHT LIKELY POPS IN THE NORMAL NORTHWEST WIND LOCATIONS THROUGH THE TIME PERIOD. ALTHOUGH ACCUMULATIONS WON/T BE LARGE...STILL THINK THERE WILL BE SOME AREAS IN THE WEST AND EAST OF MUNISING THAT WILL HAVE A FEW INCHES OF SNOW ON THE GROUND BY FRIDAY. BEST OPPORTUNITY FOR ACCUMULATIONS WILL BE OVER THE WEST...WITH THE EXISTING SNOW ON THE GROUND FROM TONIGHT. MODELS REALLY DIFFER ON THE HANDLING OF A SHORTWAVE DIVING SOUTHEAST TOWARDS THE GREAT LAKES REGION ON FRIDAY AND ACROSS THE AREA ON SATURDAY OR SUNDAY. THIS SHORTWAVE HAS A LONG JOURNEY AHEAD OF IT (CURRENTLY NORTH OF HAWAII) AND NEEDS TO ROUND THE RIDGE OVER THE WEST AND POTENTIALLY MERGE WITH THE ANOTHER WAVE IN NORTHWEST CANADA. WITH THAT LONG OF A DISTANCE TO TRAVEL...IT/S NOT SURPRISING THAT THERE ARE DIFFERENCES IN THE GEM/ECMWF/GFS ON THE SHORTWAVE AND POTENTIAL CLIPPER SYSTEM MOVING THROUGH THE AREA. 12Z GEM/GFS WERE FAIRLY SIMILAR ON THE WAVE AND CLIPPER MOVING THROUGH ON FRIDAY NIGHT INTO SATURDAY MORNING...WHILE THE 12Z ECMWF WAS MUCH SLOWER AND KEEPS THE CLIPPER NORTH OF THE AREA (MOVING THROUGH NORTHERN ONTARIO ON SATURDAY NIGHT). 00Z RUNS HAVE FLIPPED THE GEM/ECMWF IDEAS WITH THE 00Z GFS STAYING SIMILAR. THESE DIFFERENCES LEAD TO LITTLE OR NO CONFIDENCE FOR THAT TIME FRAME OTHER THAN THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE. USING A GENERAL CONSENSUS OF THE MODELS GIVES LOW END CHANCE POPS FOR THE WEEKEND. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 127 AM EDT MON OCT 21 2013 EXPECT IFR CIGS TO PREDOMINATE THIS MRNG AT IWD WHILE CONDITIONS DETERIORATE TO IFR AT CMX WITH WSHFT TO AN UPSLOPE WNW COMPONENT ASSOCIATED WITH SFC LO SHIFTING NEWD INTO ERN LK SUP. IFR CONDITIONS MAY OCCUR AT SAW AS WELL. ONCE THE DEEPENING LO MOVES INTO LK SUP LATER THIS MRNG...W WINDS WL TURN QUITE GUSTY...ESPECIALLY AT THE MORE EXPOSED CMX LOCATION. WITH THE ARRIVAL OF SOMEWHAT DRIER LLVL AIR...PLAN ON A SLOW IMPROVEMENT TO MVFR DESPITE PERSISTENT UPSLOPE WIND COMPONENT. SAW SHOULD SEE VFR CIGS IN DOWNSLOPE FLOW. ARRIVAL OF ANOTHER LO PRES TROF THIS EVNG WL BRING IFR CONDITIONS/SOME SHSN AT IWD/CMX. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 401 PM EDT SUN OCT 20 2013 A LOW CENTERED OVER MUCH OF MINNESOTA AN NORTHERN IOWA WILL SLIDE ACROSS THE UPPER GREAT LAKES TONIGHT THROUGH EARLY MONDAY. EXPECT THIS LOW TO LIFT SLOWLY INTO QUEBEC MONDAY AFTERNOON WHILE KEEPING A TROUGH OVER THE UPPER GREAT LAKES THROUGH THURSDAY. A PERIOD OF 35KT GUSTS WILL BE POSSIBLE OVER S LAKE SUPERIOR STARTING MID MORNING MONDAY /OUT OF THE W/. A SECOND PUSH OF STRONGER WINDS WILL COME IN AS THE TROUGH OF LOW PRESSURE WRAPS BACK AROUND...WITH A PERIOD OF NW GALES OF 35 TO NEAR 40KTS OVER MAINLY CENTRAL AND E LAKE SUPERIOR MONDAY NIGHT INTO MID TUESDAY. WINDS WILL SLOWLY DIMINISH TUESDAY AFTERNOON...WITH GUSTS LINGERING IN THE 20 TO 30KT RANGE THROUGH THE REST OF THE WORK WEEK. BROAD HIGH PRESSURE OF IS EXPECTED TO BUILD OVER MUCH OF THE PLAINS STATES BY THURSDAY NIGHT AND SPREAD EASTWARD INTO MUCH OF EASTERN CONTINENTAL UNITED STATES...WITH A RIDGE OVER THE UPPER GREAT LAKES. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 8 AM EDT TUESDAY FOR MIZ002>004-084. WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 7 AM CDT TUESDAY FOR MIZ009. WINTER WEATHER ADVISORY FROM 1 AM TO 11 AM EDT TUESDAY FOR MIZ005. LAKE SUPERIOR... GALE WARNING FROM 11 AM THIS MORNING TO 11 AM EDT TUESDAY FOR LSZ265>267. GALE WARNING FROM 8 PM THIS EVENING TO 11 AM EDT TUESDAY FOR LSZ264. GALE WARNING FROM 11 AM THIS MORNING TO 8 AM EDT TUESDAY FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...KC MARINE...KF
AREA FORECAST DISCUSSION
NWS JACKSON MS
958 PM CDT TUE OCT 22 2013 .DISCUSSION...OVERALL THE FORECAST WAS GOOD. HOWEVER THE SHORT TEMPERATURE FORECAST PRESENTED SOME CHALLENGES. THE DEWPOINTS SEEMED TO STALL AND WERE NOT FALLING AS EXPECTED. A WEAK SHORT WAVE MOVING THROUGH THE ARKLATEX...ASSOCIATED WITH SURFACE LOW MOVING INTO THE OHIO VALLEY WAS CAUSING RETURN FLOW TO SET UP. DEWPOINTS INCREASED SLIGHTLY ACROSS PORTIONS OF THE ARKLATEX AND WERE NOT FALLING MUCH ACROSS THE CWA. TEMPERATURES WERE SLIGHTLY WARMER AS WELL. IF THE TREND CONTINUED THE RUC WOULD WORK WITH THE SOUTH/EAST STAYING IN THE LOWER TO MID 50S TONIGHT. HOWEVER...MODELS SUGGEST THE SHORT WAVE WILL CONTINUE TO LIFT NORTHEAST AND COOLING WILL CONTINUE ACROSS THE REGION THROUGH THE MORNING. DECIDED NOT TO RAISE TEMPERATURES ACROSS THE AREA BASED ON THE LATEST TRENDS...WILL KEEP VALUES GENERA LY THE SAME IN THE UPPER TO MID 40S. TVR IS ALWAYS AN OUTLIER...SO DID LOWER VALUES ABOUT TWO DEGREES AT THIS LOCATION. TRIED TO SHOW SLOWER COOLING IN THE HOURLY VALUES. OTHERWISE...THE FORECAST WAS OK. && .AVIATION....WITH THE EXCEPTION OF PATCHY LATE NIGHT/EARLY MORNING FOG...VFR CONDITIONS WILL PREVAIL THROUGH WEDNESDAY NIGHT. EC && .PRELIMINARY POINT TEMPS/POPS... JACKSON 46 67 40 74 / 0 0 0 0 MERIDIAN 45 65 37 73 / 0 0 0 0 VICKSBURG 42 67 39 75 / 0 0 0 0 HATTIESBURG 48 72 43 74 / 0 0 0 0 NATCHEZ 47 66 42 74 / 0 0 0 0 GREENVILLE 45 64 43 70 / 0 0 0 0 GREENWOOD 45 61 40 71 / 0 0 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 7/EC
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
852 PM MDT TUE OCT 22 2013 .UPDATE... NORTHWEST FLOW WAS WELL ESTABLISHED OVER THE AREA WITH CHANNELED VORTICITY MOVING SOUTHEAST ACROSS FAR EASTERN MONTANA AND WESTERN NORTH DAKOTA. A WEAK COLD FRONT WAS ADVANCING ACROSS NORTHEAST MONTANA AND WILL CLIP THE FAR EASTERN COUNTIES TONIGHT. A FEW WEAK SHOWERS WERE BRUSHING NORTHEAST MONTANA AND WILL DROP SOUTHEAST AND CLIP FALLON COUNTY TONIGHT. HAVE BUMPED POPS UP THIS EVENING FOR FALLON COUNTY...OTHERWISE THE FORECAST WAS IN GOOD SHAPE. TWH && .SHORT TERM...VALID FOR WED AND THU... UPPER RIDGE OVER THE WESTERN CONUS WILL REMAIN DOMINANT FOR THE REGION THROUGH THE SHORT TERM PERIOD...THUS GENERALLY QUIET WEATHER WILL CONTINUE FOR THE NEXT FEW DAYS. DRY DOWNSLOPE WARMING HAS ALLOWED FOR TEMPS TODAY TO GET INTO THE 60S...WITH 68 DEGREES AT LIVINGSTON AT 3PM. WEAK SHORTWAVE IN ALBERTA WILL DROP THROUGH THE NW FLOW ALOFT AND ALLOW FOR A FRONTAL PASSAGE LATE TONIGHT AND COOLER CANADIAN AIR TO OOZE INTO OUR AREA FOR TOMORROW...WITH A SHIFT TO EASTERLY WINDS. ACCOMPANYING THIS FROPA WILL BE ENOUGH SHALLOW MOISTURE TO BRING A FEW LIGHT SHOWERS OR SPRINKLES TO MAINLY OUR EAST LATE TONIGHT INTO WEDNESDAY MORNING. COULD BE SOME STRATUS BACKDOOR INTO OUR CENTRAL PARTS AND PERHAPS FOOTHILLS WEDNESDAY MORNING...AND WILL NEED TO KEEP WATCH OF THIS...THOUGH LATEST RAP IS NOT AGGRESSIVE WITH THIS AT ALL. EITHER WAY...EXPECT COOLER TEMPS WEDNESDAY WITH HIGHS A GOOD 10 DEGREES LESS THAN TODAY. THIS WILL TRANSLATE TO A CHILLIER WEDNESDAY NIGHT... ESPECIALLY FOR OUR FAR EAST PER SFC RIDGING AND LOW LEVEL DRYING. HAVE ADJUSTED LOW TEMPS AND DEWPTS FOR THIS. COOLISH AIRMASS WITH EAST WINDS WILL PERSIST TO THURSDAY THOUGH HEIGHTS WILL BEGIN TO RISE AGAIN FROM THE WEST. COULD SEE 60 DEGREES IN OUR WEST THURSDAY AFTERNOON...WITH ONSET OF WEAK LEE SIDE TROFFING BY THURSDAY NIGHT. JKL .LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE... UPPER RIDGING/DRY NW FLOW WILL BE OVER THE REGION THROUGH SAT. MODELS CONTINUE TO DIG A STRONG SHORTWAVE INTO THE PACIFIC NW SUN AND SUN NIGHT. THE GFS MAINLY DIGS IT SOUTH OF THE REGION AS AN OPEN WAVE THROUGH VERY LATE MON. MEANWHILE...THE ECMWF DIGS STRONG SHORTWAVE/JET ENERGY THROUGH THE REGION SUN NIGHT...DEVELOPING AN UPPER LEVEL LOW JUST SW OF THE REGION MON...WHERE IT MEANDERS FOR ABOUT 18 TO 24 HRS BEFORE SLOWLY SINKING SOUTH. BOTH MODELS BRING PRECIPITATION INTO THE AREA LATE SUN INTO SUN EVENING BEHIND THE COLD FRONT. 850 MB TEMPERATURES ARE FORECAST TO BE WELL BELOW ZERO DEGREES C BY 12Z MON. THESE TEMPERATURES WILL REMAIN OVER THE REGION THROUGH TUE. BOTH MODEL SOLUTIONS BRING STRONG UPPER LEVEL JET ENERGY/DIVERGENCE AND LOW/MID LEVEL FRONTOGENESIS THROUGH THE CWA SUN NIGHT INTO MON...WITH A PROLONGED PERIOD OF UPSLOPE FLOW...SO A PROLONGED SNOW EVENT IS LOOKING MORE AND MORE LIKELY. BECAUSE MODELS ARE IN SLIGHTLY BETTER AGREEMENT...I DID INCREASE THE CHANCE OF SNOW A BIT SUN NIGHT INTO MON...ESPECIALLY IN FAVORED UPSLOPE REGIONS SUCH AS THE RED LODGE FOOTHILLS...THE SHERIDAN FOOTHILLS/BIG HORN MTNS AND SOUTHEAST MONTANA FROM BIG HORN COUNTY E TOWARDS POWDER RIVER COUNTY. STILL...IT IS SEVERAL DAYS OUT...SO THERE REMAINS A GOOD DEAL OF UNCERTAINTY WITH THIS POTENTIAL SNOW EVENT. DID RAISE TEMPS A FEW DEGREES FRI AND SAT WITH UPPER LEVEL RIDGING LOOKING MORE LIKELY...THUS HIGHS ARE EXPECTED TO REACH UPPER 50S TO MID 60S. SUN LOOKS TO BE A TRANSITION DAY AS THE FRONT MOVES THROUGH...WITH UNSEASONABLY CHILLY HIGHS MON...IN THE 20S AND 30S. STC && .AVIATION... VFR CONDITIONS WILL PREVAIL OVER THE AREA TONIGHT. A WEAK COLD FRONT WILL SWITCH THE WINDS TO A MORE N TO NE DIRECTION EARLY WED MORNING...INCREASING THE POTENTIAL FOR AREAS OF MVFR CEILINGS WED MORNING THROUGH EARLY WED AFTERNOON. STC/AAG && .PRELIMINARY POINT TEMP/POPS... WED THU FRI SAT SUN MON TUE ----------------------------------------------------------- BIL 040/053 033/055 040/063 040/063 038/053 028/032 018/032 00/B 00/U 00/U 00/U 02/W 55/S 41/B LVM 033/055 029/061 036/063 035/064 035/052 026/034 011/031 00/B 00/U 00/U 00/U 03/W 55/S 32/J HDN 036/053 029/057 034/064 035/064 038/054 029/034 021/032 00/B 00/U 00/U 00/U 02/W 56/S 41/B MLS 040/051 028/052 033/062 035/062 038/056 029/034 022/034 02/W 00/B 00/U 00/U 01/B 45/S 31/B 4BQ 038/051 028/053 034/062 036/062 037/057 030/034 023/031 02/W 00/B 00/U 00/U 01/B 45/S 42/J BHK 037/047 023/047 030/058 034/059 035/054 028/033 021/033 22/W 00/U 00/U 00/U 01/B 34/S 31/B SHR 036/052 030/058 034/063 033/063 034/056 028/028 013/027 00/B 00/U 00/U 00/U 01/B 56/S 43/J && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
1122 AM MDT MON OCT 21 2013 .UPDATE... WE MADE A SECOND MINOR FORECAST UPDATE TO FURTHER INCREASE POPS IN SOUTHEASTERN MT THIS AFTERNOON IN RESPONSE TO RECENT RADAR TRENDS. THOSE TRENDS AND RECENT RAP SIMULATIONS SUPPORT POPS OF 90 PERCENT AROUND BAKER AND POPS AS HIGH AS 50 PERCENT AT MILES CITY. SCHULTZ && .SHORT TERM...VALID FOR TDY AND TUE... SOMEWHAT UNSTABLE NORTHWEST FLOW WILL CONTINUE ACROSS THE REGION TODAY. THIS WILL CONTINUE TO PRODUCE SOME LIGHT SCATTERED SHOWERS ON THE PLAINS AND PERHAPS SOME LIGHT SNOW IN THE HIGHER BIG HORNS. FORCING DOES NOT LOOK TO ORGANIZED AND IS RELATED TO OVERRUNNING OF A WEAK BAROCLINIC ZONE IN THE EAST WITH ASSOCIATED WARM AIR ADVECTION. UPSLOPE INTO NORTH FACING SLOPES OF HIGHER TERRAIN ALSO PLAYING A ROLE. HOWEVER...MODELS AGREE THAT RIDGING WILL SHIFT EAST BY EVENING AND KEEP THE BULK OF THIS ACTIVITY IN THE DAKOTAS BY TUESDAY. I MADE SOME SLIGHT ADJUSTMENTS TO POPS...RAISING THEM SOME IN THE FALLON COUNTY VICINITY AS THIS PATTERN FAVORS THAT AREA. MAINLY DRY CONDITIONS AND WARMER TEMPERATURES ARE THEN EXPECTED FOR TUESDAY. BT .LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN... A MAINLY DRY NW FLOW WILL BE OVER THE REGION THROUGH SAT. CONFIDENCE STARTS TO BREAK DOWN ON SUN WHEN MODELS BRING A STRONG SHORTWAVE S TOWARD THE AREA FOR A POSSIBLE SYSTEM SUN AND MON. A WEAK BACKDOOR COLD FRONT WILL MOVE INTO THE AREA ON WED. GFS SHOWED SOME MOISTURE AND FRONTOGENESIS WITH THE FRONT SO INTRODUCED SLIGHT CHANCE POPS OVER AREAS E OF KBIL WED MORNING. AIRMASS WILL DRY OUT IN THE AFTERNOON. DRY WEATHER WILL PREVAIL THU THROUGH SAT. ON SUN...LATEST GFS BROUGHT A WAVE QUICKLY S INTO THE AREA WHILE THE ECMWF KEPT THE WAVE TO THE N OF THE CANADIAN BORDER. KEPT SUN MAINLY DRY AS THE GFS HAS NOT BEEN CONSISTENT IN BRINGING THE WAVE SO QUICKLY S. BY MON BOTH MODELS HAVE QPF ACROSS THE ENTIRE AREA...SO HAVE POPS ACROSS THE AREA SUN NIGHT AND MON. BOTH MODELS DROP 850 MB TEMPERATURES BELOW ZERO DEGREES C DURING MON SO ANY PRECIPITATION WOULD BE A MIX OF RAIN AND SNOW OR ALL SNOW. WILL NEED TO WATCH MODEL TRENDS WITH THIS SYSTEM SINCE IT IS STILL FAR OUT IN TIME. OTHERWISE...TEMPERATURES WILL BE NEAR SEASONABLE VALUES THROUGH SAT. ARTHUR && .AVIATION... SCATTERED SHOWERS WILL IMPACT ROUTES EAST OF BILLINGS TODAY...WITH LOCALIZED MVFR CONDITIONS IN THE HEAVIER SHOWERS. THE BIG HORN MOUNTAINS WILL LIKELY BE OBSCURED AT TIMES TODAY. CANNOT RULE OUT AN ISOLATED SHOWER AROUND BILLINGS TODAY...HOWEVER EXPECT TO VFR CONDITIONS TO PREVAIL. CHURCH && .PRELIMINARY POINT TEMP/POPS... TDY TUE WED THU FRI SAT SUN ------------------------------------------------------- BIL 061 039/061 038/057 037/054 040/060 039/060 038/056 2/N 00/B 00/B 00/U 00/U 00/U 00/U LVM 058 035/062 035/058 035/061 034/060 035/059 033/053 1/N 00/N 00/U 00/U 00/U 00/U 01/U HDN 062 038/062 037/057 035/057 035/061 036/062 035/057 2/W 00/B 01/B 00/U 00/U 00/U 00/U MLS 058 039/058 039/055 034/052 034/060 035/058 036/054 5/W 10/B 02/W 00/U 00/U 00/U 01/U 4BQ 056 038/057 037/055 035/053 035/059 036/059 035/055 4/W 10/B 02/W 00/B 00/U 00/U 00/U BHK 051 037/052 036/051 031/048 031/055 033/054 034/055 9/W 21/E 12/W 00/U 00/U 00/B 01/B SHR 057 038/059 037/056 034/058 033/061 032/059 034/056 2/W 00/B 00/B 00/U 00/U 00/U 00/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
620 PM CDT TUE OCT 22 2013 .AVIATION... 00Z TAFS FOR KOMA...KLNK...KOFK. PATCHY MVFR CEILINGS AROUND KOMA AND KOFK SHOULD END EARLY THIS EVENING WITH MAINLY VFR CONDITIONS THEN LATER TONIGHT. EXPECT VARIABLE CLOUDINESS LATE EVENING...WHICH SHOULD THEN INCREASE ABOVE 8000 FEET AFTER MIDNIGHT AT KOFK THEN AFTER 07Z-09Z AT KOMA AND KLNK. AS THE FAST MOVING UPPER LEVEL DISTURBANCE DROPS SOUTHEAST THROUGH THE REGION...LIGHT MIXED PCPN COULD DEVELOP AT KOFK WITH MVFR CEILINGS BUT PROBABLY VFR VSBYS. MVFR CEILINGS ALSO POSSIBLE AT KOMA AFTER ABOUT 14Z WEDNESDAY. MILLER && .PREV DISCUSSION... /ISSUED 254 PM CDT TUE OCT 22 2013/ SHORT TERM...TONIGHT THROUGH FRIDAY. THE FIRST CLIPPER SYSTEM WAS MOVING WELL SOUTHEAST OF THE REGION THIS AFTERNOON. MEANWHILE...THE NEXT CLIPPER WAS NOTED COMING OUT OF ALBERTA. 12Z UPPER AIR CHARTS SHOWED ABOUT 20 METER HEIGHT FALLS AT 500 MB...WITH SATURATION AT 700 MB. THIS WILL CONTINUE TO DIVE SOUTHEAST...AND COULD BRING SOME PRECIP TO NORTHEAST NEBRASKA LATE TONIGHT AFTER 09Z...ALTHOUGH LATEST 18Z RUN OF THE RAP AND 12Z ECMWF SUGGEST THAT MEASURABLE PRECIP COULD EVEN HOLD OFF UNTIL AFTER 12Z IN NORTHEAST NEBRASKA. THERMAL PROFILES SUGGEST THIS COULD BE A RAIN/SNOW MIXTURE ALONG THE NE/SD BORDER REGION. CLIPPER THEN CONTINUES TO MOVE EAST SOUTHEAST AND BRINGS PRECIP CHANCES DOWN THE MISSOURI RIVER THROUGH THE MORNING AND INTO THE AFTERNOON...WHERE IT COULD BE A RAIN/SNOW MIXTURE EARLY IN THE MORNING IN NEBRASKA AND NORTHWEST IOWA...BUT AS TEMPS WARM...LIKELY BECOMING ALL RAIN BY 15Z AND BEYOND. NOT EXPECTING ANY ACCUMULATION THOUGH...JUST A RAIN/SNOW MIX POSSIBLE. PRECIP CHANCES WILL CONTINUE TO WIND DOWN THROUGH THE AFTERNOON AND END ALTOGETHER BY WEDNESDAY EVENING. THE NAM ALSO HAD A SLIGHTLY MORE WESTERN TRACK...WHICH SEEMED TO BE TOO FAR WEST GIVEN THE PLACEMENT OF THE DYNAMICS. BEYOND THEN...NO REAL WEATHER CONCERNS AS HIGH PRESSURE SETTLES ACROSS THE PLAINS. THIS WILL RESULT IN A COUPLE OF COLD NIGHTS WEDNESDAY NIGHT...AND EVEN A COUPLE OF DEGREES COLDER THURSDAY THAN WEDNESDAY NIGHT WITH MOSTLY CLEAR SKIES. DAYTIME TEMPS DO REBOUND INTO THE MID/UPPER 50S BY FRIDAY AS SOUTHWEST FLOW RETURNS TO THE REGION. DEWALD LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. EXTENDED MODELS MAINTAIN SIMILAR TRENDS IN BREAKING DOWN THE WESTERN RIDGE OVER THE WEEKEND AS UPPER WAVE DROPS INTO THE NORTHERN ROCKIES WITH DRY AND GENERALLY MILD CONDITIONS THROUGH THIS TIME. PATTERN TURNS MORE ACTIVE EARLY NEXT WEEK. SOME TIMING ISSUES SHOW UP ON MONDAY WITH COLD FRONT THAT MOVES THROUGH THE AREA WITH A BLENDED SOLUTION USED FOR THE FORECAST. ECMWF HOLDS A STRONGER UPPER WAVE FURTHER TO THE NORTHWEST THAN THE MORE PROGRESSIVE AND LESS AMPLIFIED GFS THROUGH TUESDAY. CHANCE POPS WERE CONTINUED FOR MONDAY INTO TUESDAY WITH PRECIP TYPE LESS CERTAIN DEPENDING ON TIMING OF THE COLDER AIR. FOBERT && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1131 PM CDT SUN OCT 20 2013 .UPDATE... ISSUED AT 1130 PM CDT SUN OCT 20 2013 NO CHANGES NECESSARY THIS UPDATE PERIOD. UPDATE ISSUED AT 936 PM CDT SUN OCT 20 2013 CLEARING CONTINUES TO EXPAND ACROSS SOUTHERN MB AND LOOKS TO BE ENTERING FAR NORTHERN FA. WITH CURRENT TEMPERATURES AS THEY ARE EVEN WITH MODEST MIXING ANY CLEARING SHOULD BE ABLE TO QUICKLY DROP TEMPERATURES TO EXPECTED MINIMUMS SO FOR NOW WILL HOLD WITH FORECAST MINS. UNTIL CLOUDS DECREASE ADDED FLURRIES WITH WEAK RETURNS FROM KMVX-88D. MADE MORE ADJUSTMENTS TO CLOUD TRENDS WITH REMAINDER OF FORECAST OK. UPDATE ISSUED AT 641 PM CDT SUN OCT 20 2013 BIG CHALLENGE TONIGHT WILL BE MINIMUM TEMPERATURES WHICH WILL HINGE ON CLOUD TRENDS. SOME BREAKS SHOWING UP IN SOUTHERN MB HOWEVER STILL PRETTY SOLID CLOUD COVER ACROSS THE FA. WILL BE MONITORING CLOUD TRENDS THROUGH THE EVENING. AT THIS POINT NOT PLANNING ANY CHANGES OTHER THAN ADJUSTING CLOUD COVER A BIT. && .SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT) ISSUED AT 316 PM CDT SUN OCT 20 2013 CHALLENGES THROUGH THE PERIOD INCLUDE LOW END PRECIPITATION CHANCES AND TEMPERATURES. GFS/NAM/ECMWF/GEM IN REASONABLE AGREEMENT AND WILL FOLLOW AND BLENDED MODEL SOLUTION. 20 UTC SURFACE ANALYSIS SHOWS THE SURFACE LOW SOUTHWEST OF MINNEAPOLIS AND MOST OF ITS ASSOCIATED PRECIPITATION ACROSS THE MN ARROWHEAD INTO NORTHWEST WI. A COUPLE SURFACE OBS ACROSS WEST CENTRAL MN STILL REPORTING LIGHT RAIN...BUT WITH VISIBILITY OF 10 SM...MOST LIKELY JUST SOME LINGERING SPRINKLES. WILL CONTINUE THIS DRYING TREND INTO THE EARLY EVENING WITH ONLY SOME 20 POPS ACROSS THE LAKE OF THE WOODS REGION OVERNIGHT AS THE SURFACE LOW PIVOTS BACK TO THE NORTH AND ITS INVERTED TROUGH PINWHEELS ABOUT THE INTERNATIONAL BORDER. THERE IS ABUNDANT CLOUD COVER UPSTREAM...BUT IT IS MORE CELLULAR IN NATURE...SO IT/S DIFFICULT TO SAY HOW MUCH CLEARING WILL OCCUR OVERNIGHT...ESPECIALLY WHEN THE RAP 925 HPA RH SHOWS SATURATED CONDITIONS THROUGH MONDAY MORNING. WILL SHOW SOME CLEARING WEST OF THE VALLEY BY 12 UTC MONDAY...BUT THIS MAY BE OVERLY OPTIMISTIC. EITHER WAY...WITH HIGHS THIS AFTERNOON IN THE 30S...NIGHTTIME LOWS IN THE 20S SEEM REASONABLE. BEST CHANCE FOR PRECIPITATION MONDAY WILL CONTINUE ACROSS THE LAKE OF THE WOODS REGION WITH ALL OTHER AREAS DRY. SHOULD SEE A BIT MORE SUN TO THE SOUTH AND WEST...BUT COLD AIR MASS WILL KEEP HIGH TEMPERATURES IN THE 30S. NORTH-NORTHWEST WIND WILL PERSIST... BUT WITH A WEAKENING PRESSURE GRADIENT...SHOULD BE A BIT LOWER FROM 10 TO 15 MPH. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 316 PM CDT SUN OCT 20 2013 CANADIAN HIGH PRESSURE DIVES SOUTH ACROSS THE NORTHERN PLAINS TUESDAY AND WEDNESDAY FOR MOSTLY DRY CONDITIONS. HOWEVER... PERSISTENT CYCLONIC FLOW ALOFT COMBINED WITH HIGHER MID-LEVEL MOISTURE WILL RESULT IN QUITE A BIT OF CLOUDS. MID-LEVEL THERMAL RIDGE WILL NUDGE EASTWARD...ALLOWING FOR A LITTLE WARMING EACH DAY...SO THAT HIGHS BY WEDNESDAY SHOULD APPROACH 40 DEGREES. THIS IS STILL 10 TO 15 DEGREES BELOW MID-LATE OCTOBER NORMALS. WED NIGHT-SUNDAY...NORTHWEST FLOW ALOFT THOUGH THE PERIOD. 12Z MODELS ARE IN GOOD AGREEMENT INITIALLY...BUT QUICKLY DISAGREE WITH A STRONGER WAVE FRIDAY INTO SUNDAY. THE GFS/GEM ARE MUCH QUICKER AND FURTHER WEST WITH THIS WAVE THAN THE ECMWF. THE GFS/GEM BRING PRECIP INTO NORTHWEST MINNESOTA WITH THIS FEATURE...WHILE THE ECMWF IS BASICALLY DRY THROUGH THE PERIOD. TEMPERATURES WOULD ALSO BE AFFECTED WITH EXACTLY WHERE THIS WAVE TRACKS. THE BLEND OF MODELS IS LIKELY THE BEST COURSE OF ACTION. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 1130 PM CDT SUN OCT 20 2013 WILL SEE VFR CONDITIONS THROUGH THE FORECAST PERIOD. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...VOELKER SHORT TERM...ROGERS LONG TERM...ROGERS/TG AVIATION...VOELKER
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1058 PM EDT TUE OCT 22 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL CROSS THE OHIO VALLEY TONIGHT...BRINGING RAIN TO THE REGION...MIXING WITH SNOW IN SOME LOCATIONS DURING THE EARLY MORNING HOURS. MUCH COLDER AIR WILL MOVE IN ON WEDNESDAY...WITH BELOW NORMAL TEMPERATURES AND OCCASIONAL LIGHT RAIN OR SNOW SHOWERS EXPECTED THROUGH THE START OF THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... TEMPERATURES HAVE DROPPED AND DEW POINTS HAVE RISEN A BIT MORE RAPIDLY ACROSS THE NORTHWESTERN CWA THAN ORIGINALLY FORECAST. ALREADY TEMPS ARE IN THE MID 30S THERE. CURRENT RADAR MOSAIC SHOWS BROKEN BANDS OF LIGHT RAIN ACROSS THE REGION. EXPECTING THE SLIGHTLY MORE INTENSE PRECIP CURRENTLY OVER INDIANA TO GRADUALLY FILL IN A LITTLE MORE AS LOW PRESSURE /ABOUT TO ENTER SW INDIANA/ SLIDES INTO THE LOWER OHIO VALLEY AND SKIRTS THE SOUTHERN CWA. THE LATEST HRRR AND RAP13 RUNS BOTH HAVE A PRETTY GOOD HANDLE ON CURRENT PRECIPITATION TRENDS AND BOTH SHOW THE QPF FILLING IN A BIT MORE AS THE PRECIP MOVES ACROSS THE CWA EARLY WEDNESDAY MORNING. STILL EXPECTING A RAIN/SNOW MIX TO DEVELOP OVER THE NEXT SEVERAL HOURS AS TEMPS CONTINUE TO DROP OVERNIGHT. PREVIOUS DISCUSSION FOLLOWS... A COMPLICATED FORECAST SCENARIO HAS SET UP FOR TONIGHT...WITH SEVERAL CHALLENGES INVOLVING TIMING...TEMPERATURE...AND PRECIPITATION TYPE. THE OVERALL SCENARIO IS IN GOOD AGREEMENT (AS IT SHOULD BE WITHIN A DAY)...BUT UNFORTUNATELY THERE ARE A FEW KEY DIFFERENCES IN THE DETAILS. THE FIRST KEY TO THE FORECAST IS TIMING. AS A GENERAL RULE FOR THE MODEL RUNS TODAY...THE HIGHER-RESOLUTION THE MODEL...THE SLOWER THE PROGRESSION OF THE WEATHER SYSTEM. THE GFS AND ECMWF ARE ON THE FAST SIDE OF THE SOLUTIONS...ENDING THE MAJORITY OF PRECIPITATION IN THE ILN CWA BY 12Z. THE ARW/NMM RUNS AND NAM12 ARE SLOWER...WITH THE BULK OF THE PRECIPITATION STILL IMPACTING THE AREA AT DAYBREAK. IN REALITY...THE CURRENT POSITION OF THE SURFACE LOW INDICATES A SCENARIO SOMEWHERE BETWEEN THE TWO EXTREMES. JUST NORTH OF THE TRACK OF THE LOW...AN AXIS OF 850MB CONVERGENCE WILL COMBINE WITH LIFT FROM THE SHORTWAVE TO GENERATE AN AREA OF STEADY PRECIPITATION. THE GENERAL TRACK OF THE BEST FORCING IS IN GOOD AGREEMENT...SANS THE WRF-ARW (A LITTLE FURTHER SOUTH) AND THE RAP (A LITTLE FURTHER NORTH). QPF AMOUNTS OF A FEW TENTHS OF AN INCH LOOK POSSIBLE ALONG THIS AXIS...STRETCHING FROM CENTRAL INDIANA THROUGH SOUTHEASTERN OHIO. CATEGORICAL POPS WERE REQUIRED THROUGH THIS AREA...WITH ONLY THE SLIGHT TIMING CONCERNS PREVENTING 100-POPS AND EVEN GREATER DETAIL FROM BEING USED. BETWEEN THE DIURNAL CYCLE AND THE EXTRA PUSH OF COLD AIR BEHIND THE SURFACE LOW...TEMPERATURES ARE EXPECTED TO FALL INTO THE LOWER-TO-MID 30S (NORTHWEST CWA) TO AROUND 40 (SOUTHERN CWA) TONIGHT. IT HAS BECOME EVIDENT THAT THESE TEMPERATURES WILL BE COLD ENOUGH TO SUPPORT SNOW MIXING IN WITH RAIN...WITH (FOR CERTAIN LOCATIONS) SNOW LIKELY EVEN BECOMING THE DOMINANT PRECIPITATION TYPE FOR A COUPLE HOURS NEAR DAYBREAK. THE CRUX OF THIS FORECAST IS THE TIMING AND PLACEMENT OF THESE TEMPERATURES...JUXTAPOSED WITH THE AXIS OF HEAVIEST PRECIPITATION. MUCH OF THE NORTHERN TWO-THIRDS OF THE CWA ARE LIKELY TO EXPERIENCE A BIT OF WET SNOW MIXING WITH RAIN. HOWEVER...THERE WILL BE A WINDOW FOR A COUPLE HOURS IN WHICH AN AXIS FROM RICHMOND IN TO XENIA OH APPEARS TO BE COLD ENOUGH TO SUPPORT SNOW AS THE PRIMARY PRECIPITATION TYPE...WHILE MODERATE PRECIPITATION INTENSITY IS STILL OCCURRING. THIS IS WHERE SOME OF THE SUBTLE DIFFERENCES IN TEMPERATURE FORECASTS CAN HAVE A BIG IMPACT. THE HIGHER-RESOLUTION MODELS ALLOW FOR AN AREA OF DYNAMIC COOLING OCCURRING WITH THE PRECIPITATION...A LEGITIMATE POSSIBILITY (ONE UNTOUCHED BY THE COARSER MODELS) THAT WOULD INCREASE CHANCES FOR SNOW. GROUND TEMPS ARE QUITE WARM (MID TO UPPER 40S) AND IT IS VERY UNLIKELY THAT ANY IMPACTS WILL BE FELT ON PAVEMENT. HOWEVER...WET ACCUMULATIONS ON GRASS OR RAISED SURFACES WILL BE POSSIBLE IN THIS CORRIDOR...AND THE FORECAST GRIDS WILL ALLOW FOR SEVERAL TENTHS OF AN INCH IN THE AFOREMENTIONED LOCATIONS. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... TEMPERATURES WILL UP WARM ENOUGH TO FORCE ALL PRECIPITATION TO RAIN BY MID-MORNING ON WEDNESDAY. THE WEATHER PATTERN FOR THE NEXT TWO DAYS WILL LACK ANY SIGNIFICANT SMALL-SCALE FEATURES...WITH THE BROAD TROUGH OVER THE EASTERN HALF OF THE CONTINENT HOLDING GENERAL CONTROL OVER THE WEATHER PATTERN THROUGH THE WEEKEND. COLD TEMPERATURES WILL BE THE MAIN STORY FOR THE REST OF THE WEEK...WITH 850MB TEMPS AS LOW AS -4 TO -7 DEGREES CELSIUS. THE MAX TEMPS IN THE MID TO UPPER 40S WILL BE A SOLID 15 DEGREES BELOW NORMAL. ANY PRECIPITATION DURING THIS TIME FRAME IS EXPECTED TO BE LIGHT AND SHOWERY...WITH RAIN BEING THE DOMINANT PRECIPITATION TYPE...BUT SOME LIGHT SNOW MIXING IN DURING THE OVERNIGHT HOURS. THE COLD AIR ALOFT MAKES FOR A RATHER UNCERTAIN CLOUD FORECAST...WITH A DIVERSE ARRAY OF SPLOTCHY RH FIELDS BETWEEN DIFFERENT MODEL RUNS. THIS WILL HAVE AN OBVIOUS IMPACT ON TEMPERATURES...MOST IMPORTANTLY ON THE POTENTIAL FOR FREEZING CONDITIONS ON WEDNESDAY NIGHT AND THURSDAY NIGHT. THE AIR MASS WILL BE EASILY COLD ENOUGH TO SUPPORT THE FIRST WIDESPREAD FREEZE OF THE SEASON FOR THE ILN CWA...BUT THE CLOUD FORECAST LEAVES THIS QUESTION UNANSWERED. THERE WAS ENOUGH CONFIDENCE FOR A THIRD-PERIOD FREEZE WATCH...WHICH HAS BEEN ISSUED FOR MOST OF THE CWA FOR WEDNESDAY NIGHT INTO THURSDAY MORNING. RAW MODEL TEMPS (WHICH DIP INTO THE 20S IN A FEW PLACES ON WEDNESDAY NIGHT) ARE ACTUALLY EVEN MORE FAVORABLE FOR THURSDAY NIGHT...SO ADDITIONAL HEADLINES LOOK FAIRLY LIKELY IN THE FUTURE. && .LONG TERM /FRIDAY THROUGH TUESDAY/... UPPER TROUGH WILL MOVE EAST OF THE FA THROUGH THE DAY ON FRIDAY. WINDS OFF OF THE LAKE WILL ALLOW FOR SOME CLOUD COVER ACROSS NORTHERN PORTIONS OF THE FA ON FRIDAY. ELSEWHERE ACROSS THE FA MOSTLY CLEAR CONDITIONS WILL BE PRESENT AND THEREFORE WIDESPREAD FROST CAN BE EXPECTED FRIDAY MORNING. TEMPERATURES WILL ONLY RISE INTO THE 40S ON FRIDAY WITH COOL AIR STILL IN PLACE. PRECIPITATION ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE WILL STAY NORTH OF THE FA SATURDAY INTO SATURDAY NIGHT. WINDS WILL PICK UP HOWEVER DURING THE DAY ON SATURDAY WITH WIND GUSTS OF 20 TO 30 MPH POSSIBLE. THESE SOUTHERLY WINDS WILL ALLOW TEMPERATURES TO BE A LITTLE WARMER ON SATURDAY. HIGH TEMPERATURES ON SATURDAY WILL BE IN THE 50S. THESE VALUES ARE STILL BELOW NORMAL FOR THIS TIME OF YEAR. WITH THE PASSAGE OF THE UPPER LEVEL DISTURBANCE COOLER AIR WILL WORK INTO THE REGION FOR SUNDAY. THIS WILL LIMIT HIGH TEMPERATURES ON SUNDAY TO THE UPPER 40S TO LOW 50S ACROSS MOST LOCATIONS. WARMER AIR WILL WORK INTO THE REGION FOR MONDAY AND TUESDAY WITH SOUTHERLY FLOW DEVELOPING. A LOW PRESSURE SYSTEM WILL APPROACH THE AREA ON TUESDAY AND RAIN SHOWERS ASSOCIATED WITH THIS SYSTEM WILL BEGIN TO WORK INTO THE REGION ON TUESDAY. RAIN SHOWERS ARE EXPECTED TO OVERSPREAD THE ENTIRE AREA TUESDAY NIGHT. THERE ARE STILL QUITE A FEW MODEL DISCREPANCIES ON THE EXACT TIMING AND STRENGTH OF THIS SYSTEM HOWEVER MODELS ARE IN AGREEMENT WITH BRINGING PRECIPITATION INTO THE FA. DUE TO THIS HAVE INCREASED PRECIPITATION CHANCES ACROSS THE AREA LATE TUESDAY INTO TUESDAY NIGHT. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... SOME LIGHT RAIN WILL PASS ACROSS THE TERMINALS IN THE EARLY PART OF THE TAF PERIOD BUT CONDITIONS SHOULD REMAIN VFR DURING THIS TIME. MORE SUBSTANTIAL PRECIPITATION WILL MOVE ACROSS THE REGION BETWEEN 07Z AND 14Z. THIS WILL CAUSE CONDITIONS TO LOWER ESPECIALLY WHERE SOMEWHAT HEAVIER PRECIPITATION FALLS. AT THIS POINT IT APPEARS KDAY AND PERHAPS KILN WOULD BE IMPACTED THE MOST. ALSO THESE TWO LOCATIONS HAVE THE HIGHER PROBABILITY OF HAVING SOME SNOW POSSIBLY MIXING IN WITH THE RAIN. SYSTEM WILL MOVE OUT DURING THE MORNING WITH PRECIPITATION COMING TO AN END AND CEILINGS EVENTUALLY LIFTING TO VFR. COULD GET SOME WIND GUSTS AROUND 20 KT LATE IN THE TAF PERIOD. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING FOR OHZ026-034-035-042>046-051>056-060>065- 070>074-080-082-088. KY...NONE. IN...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING FOR INZ050-058-059-066. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS/KURZ SHORT TERM...HATZOS LONG TERM...NOVAK AVIATION...
AREA FORECAST DISCUSSION
NWS TULSA OK
1148 PM CDT SUN OCT 20 2013 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. A FEW AREAS OF SHOWERS NOTED ACROSS WESTERN OK LATE THIS EVENING. THIS ACTIVITY SHOULD EXPAND EASTWARD OVERNIGHT AND COULD IMPACT THE KTUL/KRVS AND KMLC TAF SITES AROUND 10Z...AND EVENTUALLY MOVE INTO WESTERN AR AFTER 12-13Z. CIGS SHOULD REMAIN GENERALLY AROUND 5KFT. && .PREV DISCUSSION... /ISSUED 932 PM CDT SUN OCT 20 2013/ DISCUSSION... CLOUDINESS WILL BE ON THE INCREASE OVERNIGHT AS AN UPPER LEVEL DISTURBANCE APPROACHES THE AREA FROM THE WEST AND A COLD FRONT MOVES INTO NORTHEAST OKLAHOMA FROM THE NORTH. THERE IS A STRONG SIGNAL IN RECENT RUNS OF THE HRRR THAT CONFIRMS THE 12Z ECMWF AND UKMET SIGNALS THAT PRECIPITATION WILL BREAK OUT ACROSS PARTS OF CENTRAL AND EASTERN OKLAHOMA OVERNIGHT. AS SUCH...WILL ADD POPS TO AREAS SOUTHEAST OF INTERSTATE 44 LATER TONIGHT. WILL ALSO MAKE SOME MINOR TEMPERATURES CHANGES. UPDATE COMING SHORTLY. && .PRELIMINARY POINT TEMPS/POPS... TUL 46 56 39 71 / 20 50 10 0 FSM 46 61 39 70 / 10 50 30 0 MLC 46 60 37 72 / 50 50 10 0 BVO 44 55 35 69 / 10 20 10 0 FYV 42 56 33 65 / 10 50 20 10 BYV 44 56 35 64 / 10 40 20 10 MKO 44 57 37 69 / 40 50 10 0 MIO 44 56 36 67 / 10 20 10 10 F10 46 55 38 71 / 30 50 10 0 HHW 46 68 42 71 / 20 50 30 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...99 LONG TERM....99 AVIATION...18
AREA FORECAST DISCUSSION
NWS PORTLAND OR
445 AM PDT MON OCT 21 2013 .SYNOPSIS...A STRONG UPPER LEVEL RIDGE ALONG THE COAST CONTINUES TO DOMINATE THE WEATHER ACROSS THE WESTERN UNITED STATES AND CANADA... PUSHING THE MAIN PACIFIC STORM TRACK WELL NORTH INTO ALASKA. THIS WILL MAINTAIN DRY WEATHER WITH MILD DAYS AND COOL NIGHTS IN SOUTHWEST WASHINGTON AND NORTHWEST OREGON...ALONG WITH AREAS OF DENSE NIGHT AND MORNING FOG. A BIT OF EAST WIND SHOULD DEVELOP IN THE GORGE AND SPREAD INTO THE PORTLAND AND VANCOUVER METRO AREA MONDAY NIGHT... LEADING TO LESS FOG IN THESE AREAS TUESDAY MORNING. AFTER SOME POSSIBLE COASTAL DRIZZLE WEDNESDAY THE FORECAST LOOKS DRY. && .UPDATE...UPDATE ON THE FOG FOR THE METRO AREA THIS MORNING. A SOLID STRATUS DECK IS HOLDING AT ABOUT 200 FEET. SO WHILE THE LOWEST ELEVATIONS MAY NOT BE SEEING DENSE FOG WHERE MANY OF OUR OBSERVATION STATIONS ARE LOCATED...ANY CHANGING TERRAIN ABOVE 200 FEET INTERSECTING THE FOG WILL EASILY ENCOUNTER WIDELY VARYING VISIBILITY AND ENTER THE DENSE FOG. CAUTION IS STILL URGED FOR THE MORNING COMMUTE. .SHORT TERM...MONDAY THROUGH WEDNESDAY... THINGS ARE PROGRESSING IN A SOMEWHAT SIMILAR FASHION TO LAST NIGHT...WITH THE MINOR EXCEPTION THAT WE ARE STARTING TO DEVELOP AN OFFSHORE GRADIENT THROUGH THE COLUMBIA RIVER GORGE AND ALONG THE EAST SIDE OF THE WARNING AREAS. INVERSIONS ARE IN PLACE TO KEEP THE EAST WIND FROM SURFACING OUTSIDE OF THE GORGE JUST YET. THAT MEANS FAIRLY LIGHT WINDS TO EVEN A LIGHT NORTHWEST WIND AROUND PORTLAND THAT IS JOINING WITH RADIATIONAL PROCESSES TO BRING LOW CLOUDS AND FOG IN FROM THE NORTH WHERE IT HAS BEEN LOCKED IN PLACE FOR THE PAST FEW DAYS. THE COWLITZ RIVER VALLEY AND KELSO/LONGVIEW AREAS ARE AGAIN SEEING LOW STRATUS RATHER THAN DENSE FOG...AS THE COLD POOL STRATUS OVER THE PUGET SOUND PUSHES INTO THE AREA BEFORE FOG CAN DEVELOP. MEANWHILE AT THE COAST...FOG IS DENSE FROM ABOUT LINCOLN CITY SOUTHWARD...WHILE EAST WINDS ARE SHOWING UP NEAR ASTORIA KEEPING THINGS AT BAY. STILL THINK RADIATIONAL PROCESSES WILL ALLOW FOR SOME FOG HERE TOO. WE DO HAVE WIDELY VARYING VISIBILITIES...BUT LATEST HRRR GUIDANCE FOR SFC VISIBILITY WHICH HAD A DECENT HANDLE ON THE DENSE FOG YESTERDAY SUGGESTS IT REMAINS A CONCERN THROUGH THE VALID TIME OF THE CURRENT ADVISORY. HAVE SOME CONCERNS THAT WITH THE WINDS ABOVE THE SURFACE BEING A BIT STRONGER TODAY WITH THE OFFSHORE GRADIENT THAT THE FOG WILL ONLY REMAIN DENSE IN WIND SHELTERED LOCATIONS AND THAT IT WILL LIFT TO A LOW STRATUS DECK AS IS NOW TAKING PLACE IN SEVERAL LOCATIONS. WILL HANG ONTO THE VALLEY ADVISORY FOR NOW AND MONITOR THE TRENDS AS WE STILL HAVE PLENTY OF SPOTS AT THREE QUARTERS OF A MILE VISIBILITY OR LESS AND QUARTER MILE VISIBILITY AT HILLSBORO AND MCMINNVILLE. ELEVATED LOCATIONS MAY BE IN THE LOW CLOUD AND THUS IN THE FOG ANYWAYS AND CAMERAS ON I-205 DO SHOW SOME PRETTY DENSE FOG AS OF 300 AM. MEANWHILE...THE HRRR ALSO SUGGESTS THE CENTRAL COAST WILL HANG ONTO DENSE FOG AND ON THE NORTH COAST FROM TILLAMOOK SOUTH. FEEL THESE AREAS WILL KEEP LIGHT WINDS UNDER THE COASTAL LOW TO WARRANT ADDITION OF THE CENTRAL COAST INTO THE ADVISORY...AND WILL ADD THE NORTH COAST TOO DESPITE IT BEING FOCUSED ON THE SOUTHERN HALF OF THE ZONE. AREAS NORTH TOWARD ASTORIA AND INTO THE SOUTH WASHINGTON COAST ARE FEELING THE EAST WIND A BIT MORE AS SEEN IN THE MSLP ANALYSIS. ALL LOWLAND AREAS MAY ALSO EXPERIENCE SOME DRIZZLY MIST OUT OF THE LOW CLOUDS WHEN HEADING OUT THIS MORNING. THE COLD POOL DEEPENS LATER THIS MORNING...WHICH ALLOWS HIGH PRESSURE TO STRENGTHEN ENOUGH EAST OF THE CASCADES TO PUSH THE EASTERLY PRESSURE GRADIENTS INTO THE PORTLAND METRO AREA. MONDAY NIGHT/EARLY TUESDAY APPEARS TO BE THE TIME PERIOD WHERE FOG WILL HAVE A HARD TIME RE-FORMING AROUND THE PDX METRO DUE TO MODERATE EASTERLY GORGE WINDS. THERE MAY BE ENOUGH OFFSHORE COMPONENT TO KEEP THE NORTH COAST CLEAR MON NIGHT AS WELL. AS A RESULT THESE AREAS SHOULD BE A FEW DEGREES WARMER ON TUESDAY. EXPECT TEMPERATURES TODAY TO BE SOMEWHAT ON PAR WITH YESTERDAY...THOUGH GUIDANCE SUGGESTS A SMALL INCREASE ESPECIALLY FOR LOCATIONS WHERE LOW CLOUDS AND FOG LINGER THE LEAST. /KMD REST OF THE SHORT TERM DISCUSSION UNCHANGED...EASTERLY WINDS SHOULD CONTINUE THROUGH THE GORGE AND ACROSS THE PORTLAND/VANCOUVER METRO TUE NIGHT/EARLY WED...BUT SHOULD BEGIN TO EASE AS HIGH PRESSURE WEAKENS EAST OF THE CASCADES. HOWEVER...AT THE SAME TIME A WEAK UPPER LEVEL CUTOFF LOW WILL BE MEANDERING CLOSER TO THE OREGON COAST. THIS MAY KEEP FLOW EASTERLY ACROSS THE NORTHERN HALF OF OUR FORECAST AREA...WHILE DEEPENING THE MARINE LAYER AND INDUCING A SOUTHERLY WIND REVERSAL ALONG THE CENTRAL OREGON COAST. THE DEEPENING MARINE LAYER MAY BE ENOUGH TO WRING OUT SOME COASTAL DRIZZLE AND COULD EVENTUALLY SPREAD COASTAL LOW CLOUDS INTO THE WILLAMETTE VALLEY. WEAGLE .LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...WEDNESDAY NIGHT THROUGH SUNDAY...THE WEAK DRY LOW CIRCULATION OFF THE OREGON COAST AT THE END OF THE SHORT TERM PERIOD WILL DRIFT NORTH TOWARD B.C. DURING THE FIRST PART OF THE LANG TERM PERIOD...REPLACED BY A LARGER LOW OFF THE CALIFORNIA COAST. WE LOOK TO STAY DRY...THOUGH WE WILL HAVE A BIT MORE PERSISTENT LOW LEVEL MARINE LAYER NEAR THE COAST...WITH MORE NIGHT AND MORNING FOG AND LOW CLOUDS INLAND. THE FOG AND LOW CLOUDS INLAND MAY TAKE A WHILE TO BREAK OUT EACH DAY AS THE SURFACE GRADIENTS ARE LIGHTER...CAUSING AN EROSION IN AFTERNOON TEMPS. THE 12Z ECMWF AND THE GEM ARE NOW STARTING TO SHOW A SYSTEM DROPPING INTO THE PACIFIC NORTHWEST FROM OVER THE RIDGE LATE NEXT WEEKEND WHICH COULD BRING AN END TO THE DRY SPELL. THE GFS REMAINS DRY. WILL CONTINUE THE CURRENT DRY FORECAST BUT WILL NEED TO CHANGE IF THESE TRENDS CONTINUE. TOLLESON && .AVIATION...IFR CONDITIONS THE RULE BUT MORE SO UNDER STRATUS THAN FOG. SEEMS LIKE THE LOW LEVEL OFFSHORE FLOW IS SERVING TO LIFT THE DECK EVER SO SLIGHTLY. TOUGH CALL FOR THE TAFS THIS MORNING BUT AM STRONGLY CONSIDERING HAVING THE LOW DECKS PREVAIL FOR THE 12Z TAF PACKAGE VERSUS KEEPING THE FOG IN PLACE. STILL EXPECT NOTABLE TERRAIN OBSCURATION AROUND THE TERMINALS...HOWEVER. AS SUCH...AM LOOKING CLOSER TO THE 16 TO 18Z TIME FRAME FOR SCATTERING ACROSS THE NORTH WHILE HOLDING ON TO THE DECK A LITTLE LONGER FOR THE SOUTH, SAY 18 TO 20Z. LOOKS LIKE AN IFR OR WORSE DECK WILL REAPPEAR OVERNIGHT EXCEPT FOR KPDX, KTTD, AND PERHAPS KAST, WHERE EASTERLY GORGE INFLUENCE WINDS WILL KEEP CONDITIONS CLEARER. KPDX AND APPROACHES...IFR CIGS THROUGH AROUND 17Z THEN REMAINING VFR FOR THE REST OF THE PERIOD. /JBONK && .MARINE...MAIN CONCERN IS FOR IMMEDIATE NEAR SHORE SURF CONDITIONS AS LONG PERIOD SWELL IN PLACE WITH HEIGHTS NOW REACHING 6 FT AT 20 TO 21 SEC. WILL SEE SWELL PEAK NEAR 8 FT WITH WIND WAVES TACKING ON MAYBE ANOTHER FOOT FOR A TOTAL OF 9 FT FOR THE NORTHERN OUTER WATERS AT TIMES EARLY THIS EVENING. THIS IS MAKING THE COLUMBIA BAR FORECAST A BIT PROBLEMATIC AS THE AFTERNOON EBB WILL BE STRONG AND OCCURRING AROUND THIS SAME TIME. HAVE NOT SEEN MUCH IN THE WAY OF NOTABLE RISES GIVEN THE ADDED LONG PERIOD ENERGY PLUS IT IS COMING IN SOMEWHAT ANGLED ACROSS THE PRIMARY FLOW OUT OF THE MOUTH. WILL SIT TIGHT ON THE CUSP OF ISSUING A ROUGH BAR ADVISORY UNTIL PERHAPS LATER SHIFTS GAIN ADDED CONFIDENCE FROM DAYLIGHT OBSERVATIONS. THE LONG PERIOD SWELL WILL SHORTEN OVERNIGHT AS SEAS GRADUALLY EASE BACK TOWARD 6 FEET OR LESS HEADING INTO MID WEEK. WINDS DO GENERALLY STAY IN THE 15 TO 20 KT RANGE FOR GUSTS AND SLIGHTLY LESS SUSTAINED WINDS. SURFACE LOW PRESSURE JUST OFFSHORE WILL TURN WINDS LIGHT SOUTHERLY FOR A BIT MIDWEEK. /JBONK && .PQR WATCHES/WARNINGS/ADVISORIES... OR...DENSE FOG ADVISORY UNTIL 10 AM PDT THIS MORNING FOR CENTRAL OREGON COAST-CENTRAL WILLAMETTE VALLEY-GREATER PORTLAND METRO AREA-NORTH OREGON COAST-SOUTH WILLAMETTE VALLEY. WA...DENSE FOG ADVISORY UNTIL 10 AM PDT THIS MORNING FOR GREATER VANCOUVER AREA. PZ...NONE. && $$ 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 PORTLAND OR
315 AM PDT MON OCT 21 2013 .SYNOPSIS...A STRONG UPPER LEVEL RIDGE ALONG THE COAST CONTINUES TO DOMINATE THE WEATHER ACROSS THE WESTERN UNITED STATES AND CANADA... PUSHING THE MAIN PACIFIC STORM TRACK WELL NORTH INTO ALASKA. THIS WILL MAINTAIN DRY WEATHER WITH MILD DAYS AND COOL NIGHTS IN SOUTHWEST WASHINGTON AND NORTHWEST OREGON...ALONG WITH AREAS OF DENSE NIGHT AND MORNING FOG. A BIT OF EAST WIND SHOULD DEVELOP IN THE GORGE AND SPREAD INTO THE PORTLAND AND VANCOUVER METRO AREA MONDAY NIGHT... LEADING TO LESS FOG IN THESE AREAS TUESDAY MORNING. AFTER SOME POSSIBLE COASTAL DRIZZLE WEDNESDAY THE FORECAST LOOKS DRY. && .SHORT TERM...MONDAY THROUGH WEDNESDAY... THINGS ARE PROGRESSING IN A SOMEWHAT SIMILAR FASHION TO LAST NIGHT...WITH THE MINOR EXCEPTION THAT WE ARE STARTING TO DEVELOP AN OFFSHORE GRADIENT THROUGH THE COLUMBIA RIVER GORGE AND ALONG THE EAST SIDE OF THE WARNING AREAS. INVERSIONS ARE IN PLACE TO KEEP THE EAST WIND FROM SURFACING OUTSIDE OF THE GORGE JUST YET. THAT MEANS FAIRLY LIGHT WINDS TO EVEN A LIGHT NORTHWEST WIND AROUND PORTLAND THAT IS JOINING WITH RADIATIONAL PROCESSES TO BRING LOW CLOUDS AND FOG IN FROM THE NORTH WHERE IT HAS BEEN LOCKED IN PLACE FOR THE PAST FEW DAYS. THE COWLITZ RIVER VALLEY AND KELSO/LONGVIEW AREAS ARE AGAIN SEEING LOW STRATUS RATHER THAN DENSE FOG...AS THE COLD POOL STRATUS OVER THE PUGET SOUND PUSHES INTO THE AREA BEFORE FOG CAN DEVELOP. MEANWHILE AT THE COAST...FOG IS DENSE FROM ABOUT LINCOLN CITY SOUTHWARD...WHILE EAST WINDS ARE SHOWING UP NEAR ASTORIA KEEPING THINGS AT BAY. STILL THINK RADIATIONAL PROCESSES WILL ALLOW FOR SOME FOG HERE TOO. WE DO HAVE WIDELY VARYING VISIBILITIES...BUT LATEST HRRR GUIDANCE FOR SFC VISIBILITY WHICH HAD A DECENT HANDLE ON THE DENSE FOG YESTERDAY SUGGESTS IT REMAINS A CONCERN THROUGH THE VALID TIME OF THE CURRENT ADVISORY. HAVE SOME CONCERNS THAT WITH THE WINDS ABOVE THE SURFACE BEING A BIT STRONGER TODAY WITH THE OFFSHORE GRADIENT THAT THE FOG WILL ONLY REMAIN DENSE IN WIND SHELTERED LOCATIONS AND THAT IT WILL LIFT TO A LOW STRATUS DECK AS IS NOW TAKING PLACE IN SEVERAL LOCATIONS. WILL HANG ONTO THE VALLEY ADVISORY FOR NOW AND MONITOR THE TRENDS AS WE STILL HAVE PLENTY OF SPOTS AT THREE QUARTERS OF A MILE VISIBILITY OR LESS AND QUARTER MILE VISIBILITY AT HILLSBORO AND MCMINNVILLE. ELEVATED LOCATIONS MAY BE IN THE LOW CLOUD AND THUS IN THE FOG ANYWAYS AND CAMERAS ON I-205 DO SHOW SOME PRETTY DENSE FOG AS OF 300 AM. MEANWHILE...THE HRRR ALSO SUGGESTS THE CENTRAL COAST WILL HANG ONTO DENSE FOG AND ON THE NORTH COAST FROM TILLAMOOK SOUTH. FEEL THESE AREAS WILL KEEP LIGHT WINDS UNDER THE COASTAL LOW TO WARRANT ADDITION OF THE CENTRAL COAST INTO THE ADVISORY...AND WILL ADD THE NORTH COAST TOO DESPITE IT BEING FOCUSED ON THE SOUTHERN HALF OF THE ZONE. AREAS NORTH TOWARD ASTORIA AND INTO THE SOUTH WASHINGTON COAST ARE FEELING THE EAST WIND A BIT MORE AS SEEN IN THE MSLP ANALYSIS. ALL LOWLAND AREAS MAY ALSO EXPERIENCE SOME DRIZZLY MIST OUT OF THE LOW CLOUDS WHEN HEADING OUT THIS MORNING. THE COLD POOL DEEPENS LATER THIS MORNING...WHICH ALLOWS HIGH PRESSURE TO STRENGTHEN ENOUGH EAST OF THE CASCADES TO PUSH THE EASTERLY PRESSURE GRADIENTS INTO THE PORTLAND METRO AREA. MONDAY NIGHT/EARLY TUESDAY APPEARS TO BE THE TIME PERIOD WHERE FOG WILL HAVE A HARD TIME RE-FORMING AROUND THE PDX METRO DUE TO MODERATE EASTERLY GORGE WINDS. THERE MAY BE ENOUGH OFFSHORE COMPONENT TO KEEP THE NORTH COAST CLEAR MON NIGHT AS WELL. AS A RESULT THESE AREAS SHOULD BE A FEW DEGREES WARMER ON TUESDAY. EXPECT TEMPERATURES TODAY TO BE SOMEWHAT ON PAR WITH YESTERDAY...THOUGH GUIDANCE SUGGESTS A SMALL INCREASE ESPECIALLY FOR LOCATIONS WHERE LOW CLOUDS AND FOG LINGER THE LEAST. /KMD REST OF THE SHORT TERM DISCUSSION UNCHANGED...EASTERLY WINDS SHOULD CONTINUE THROUGH THE GORGE AND ACROSS THE PORTLAND/VANCOUVER METRO TUE NIGHT/EARLY WED...BUT SHOULD BEGIN TO EASE AS HIGH PRESSURE WEAKENS EAST OF THE CASCADES. HOWEVER...AT THE SAME TIME A WEAK UPPER LEVEL CUTOFF LOW WILL BE MEANDERING CLOSER TO THE OREGON COAST. THIS MAY KEEP FLOW EASTERLY ACROSS THE NORTHERN HALF OF OUR FORECAST AREA...WHILE DEEPENING THE MARINE LAYER AND INDUCING A SOUTHERLY WIND REVERSAL ALONG THE CENTRAL OREGON COAST. THE DEEPENING MARINE LAYER MAY BE ENOUGH TO WRING OUT SOME COASTAL DRIZZLE AND COULD EVENTUALLY SPREAD COASTAL LOW CLOUDS INTO THE WILLAMETTE VALLEY. WEAGLE .LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...WEDNESDAY NIGHT THROUGH SUNDAY...THE WEAK DRY LOW CIRCULATION OFF THE OREGON COAST AT THE END OF THE SHORT TERM PERIOD WILL DRIFT NORTH TOWARD B.C. DURING THE FIRST PART OF THE LANG TERM PERIOD...REPLACED BY A LARGER LOW OFF THE CALIFORNIA COAST. WE LOOK TO STAY DRY...THOUGH WE WILL HAVE A BIT MORE PERSISTENT LOW LEVEL MARINE LAYER NEAR THE COAST...WITH MORE NIGHT AND MORNING FOG AND LOW CLOUDS INLAND. THE FOG AND LOW CLOUDS INLAND MAY TAKE A WHILE TO BREAK OUT EACH DAY AS THE SURFACE GRADIENTS ARE LIGHTER...CAUSING AN EROSION IN AFTERNOON TEMPS. THE 12Z ECMWF AND THE GEM ARE NOW STARTING TO SHOW A SYSTEM DROPPING INTO THE PACIFIC NORTHWEST FROM OVER THE RIDGE LATE NEXT WEEKEND WHICH COULD BRING AN END TO THE DRY SPELL. THE GFS REMAINS DRY. WILL CONTINUE THE CURRENT DRY FORECAST BUT WILL NEED TO CHANGE IF THESE TRENDS CONTINUE. TOLLESON && .AVIATION...IFR CONDITIONS THE RULE BUT MORE SO UNDER STRATUS THAN FOG. SEEMS LIKE THE LOW LEVEL OFFSHORE FLOW IS SERVING TO LIFT THE DECK EVER SO SLIGHTLY. TOUGH CALL FOR THE TAFS THIS MORNING BUT AM STRONGLY CONSIDERING HAVING THE LOW DECKS PREVAIL FOR THE 12Z TAF PACKAGE VERSUS KEEPING THE FOG IN PLACE. STILL EXPECT NOTABLE TERRAIN OBSCURATION AROUND THE TERMINALS...HOWEVER. AS SUCH...AM LOOKING CLOSER TO THE 16 TO 18Z TIME FRAME FOR SCATTERING ACROSS THE NORTH WHILE HOLDING ON TO THE DECK A LITTLE LONGER FOR THE SOUTH, SAY 18 TO 20Z. LOOKS LIKE AN IFR OR WORSE DECK WILL REAPPEAR OVERNIGHT EXCEPT FOR KPDX, KTTD, AND PERHAPS KAST, WHERE EASTERLY GORGE INFLUENCE WINDS WILL KEEP CONDITIONS CLEARER. KPDX AND APPROACHES...IFR CIGS THROUGH AROUND 17Z THEN REMAINING VFR FOR THE REST OF THE PERIOD. /JBONK && .MARINE...MAIN CONCERN IS FOR IMMEDIATE NEAR SHORE SURF CONDITIONS AS LONG PERIOD SWELL IN PLACE WITH HEIGHTS NOW REACHING 6 FT AT 20 TO 21 SEC. WILL SEE SWELL PEAK NEAR 8 FT WITH WIND WAVES TACKING ON MAYBE ANOTHER FOOT FOR A TOTAL OF 9 FT FOR THE NORTHERN OUTER WATERS AT TIMES EARLY THIS EVENING. THIS IS MAKING THE COLUMBIA BAR FORECAST A BIT PROBLEMATIC AS THE AFTERNOON EBB WILL BE STRONG AND OCCURRING AROUND THIS SAME TIME. HAVE NOT SEEN MUCH IN THE WAY OF NOTABLE RISES GIVEN THE ADDED LONG PERIOD ENERGY PLUS IT IS COMING IN SOMEWHAT ANGLED ACROSS THE PRIMARY FLOW OUT OF THE MOUTH. WILL SIT TIGHT ON THE CUSP OF ISSUING A ROUGH BAR ADVISORY UNTIL PERHAPS LATER SHIFTS GAIN ADDED CONFIDENCE FROM DAYLIGHT OBSERVATIONS. THE LONG PERIOD SWELL WILL SHORTEN OVERNIGHT AS SEAS GRADUALLY EASE BACK TOWARD 6 FEET OR LESS HEADING INTO MID WEEK. WINDS DO GENERALLY STAY IN THE 15 TO 20 KT RANGE FOR GUSTS AND SLIGHTLY LESS SUSTAINED WINDS. SURFACE LOW PRESSURE JUST OFFSHORE WILL TURN WINDS LIGHT SOUTHERLY FOR A BIT MIDWEEK. /JBONK && .PQR WATCHES/WARNINGS/ADVISORIES... OR...DENSE FOG ADVISORY UNTIL 10 AM PDT THIS MORNING FOR CENTRAL OREGON COAST-CENTRAL WILLAMETTE VALLEY-GREATER PORTLAND METRO AREA-NORTH OREGON COAST-SOUTH WILLAMETTE VALLEY. WA...DENSE FOG ADVISORY UNTIL 10 AM PDT THIS MORNING FOR GREATER VANCOUVER AREA. PZ...NONE. && $$ 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 GREENVILLE-SPARTANBURG SC
1029 PM EDT TUE OCT 22 2013 .SYNOPSIS... A COLD FRONT WILL GRADUALLY MOVE OFFSHORE TONIGHT WITH A COLD CANADIAN AIR MASS GRADUALLY SETTLING OVER THE REGION ON WEDNESDAY. THIS AIRMASS IS EXPECTED TO LINGER WELL INTO THE WEEKEND AND BRING THE COLDEST TEMPERATURES SO FAR THIS SEASON. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 1015 PM...A POTENT UPR SHORTWAVE CONTINUES TO DIVE INTO THE BASE OF A POSITIVELY-TILTED TROF AXIS INVOF THE MID MS VLY THIS EVENING. SO FAR...THE FRONT SIDE OF THE SYSTEM HAS SLOWED/STALLED...WITH MOISTURE AND LIFT CONTINUING TO STREAM FROM SW TO NE IN THE MID LVLS. A FEW WEAK RETURNS OCCASIONALLY SHOWING UP ON RADAR...PRIMARILY IN THE NC PIEDMONT AND NRN MTNS. SO WILL CONTINUE TO KEEP A SLGT CHC TO LOW-END CHC POP FOR A FEW MORE HOURS. ALSO...WITH A COLD FRONT STALLED ALONG THE BLUE RIDGE...THE DEWPTS ARE RUNNING QUITE A BIT HIGHER THAN TRENDS IN THE GRIDS. SO THOSE WERE ADJUSTED INTO THE OVERNIGHT. THIS MAY RESULT IN A BIT MORE FOG OUT THERE THAN PREVIOUSLY THOUGHT...BUT NO WIDESPREAD DENSE FOG IS EXPECTED. MEANWHILE...SOME SHOWERS AND A STRONGER FRONT PUSH INTO THE OH VLY ATTM ASSOCIATED WITH THE POTENT SHORTWAVE...ACCOMPANIED BY BATCH OF GENERALLY LGT SHWRS. THIS MOISTURE IS EXPECTED TO ARRIVE AT THE TN/NC BORDER AROUND DAYBREAK...SO POPS THERE WILL CONTINUE TO BE CARRIED. THE COLD ADVECTION DOESN/T REALLY GET GOING UNTIL MID WED MORNING...SO MIN TEMPS SHUD BE GENERALLY IN THE 40S TO LWR 50S...WITH 30S ABOVE ABOUT 5000 FT. PERHAPS MT MITCHELL COULD SEE A SNOW FLAKE OR TWO...BUT OTHERWISE THE SHWRS SHUD BE RAIN. THE NRN STREAM WAVE WILL PUSH A STRONGER FRONT ACROSS THE REGION A LITTLE AFTER 12 UTC ON WED. STRONG COLD ADVECTION AND 35 KT NW FLOW AT 850 MB WILL RESULT IN SHOWERS ALONG THE TN LINE. FREEZING LEVELS WILL BE HIGH THROUGH THE DAY...AND ANY SNOW SHOWER ACTIVITY SHOULD BE CONFINED TO ELEVATIONS ABOVE 5000 FEET. NOT EXPECTING WINDS TO REACH LAKE WIND CRITERIA OVER THE MOUNTAINS...THOUGH THE NRN MTNS COULD BE CLOSE. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... AS OF 2 PM EDT TUESDAY...THE SHORT TERM FCST PICKS UP AT 00Z ON THURSDAY WITH THE BROAD UPPER TROF AXIS JUST TO OUR NORTH AND UPPER RIDGING MAINTAINING ITSELF OVER THE FAR WESTERN CONUS. THE UPPER RIDGE WILL GRADUALLY SHIFT EASTWARD ON FRIDAY AND START TO DEAMPLIFY AS IT MOVES OFFSHORE AND HEIGHTS RISE OVER THE CAROLINAS. ON THURSDAY...COOLER AND DRIER SFC HIGH PRESSURE WILL BE PUSHING INTO THE CWFA AS WE BEGIN THE PERIOD. NWLY TO WLY LOW LVL WINDS WILL PERSIST THROUGHOUT THE DAY WITH MORE OF A WLY COMPONENT EXPECTED DURING THE LATER HALF OF THE DAY/EVENING. MOST OF THE MODEL GUIDANCE INDICATES THAT A LIMITED PLUME OF DEEPER LAYER MOISTURE WILL MOVE ACROSS THE CWFA DURING THE DAY...BUT WILL LIKELY NOT AMOUNT TO MUCH IF ANY PRECIP. THE BEST CHANCES WILL BE CONFINED TO THE NORTHERN MTS AND ALONG THE TENN/NC BORDER. THE MAIN CONCERN WILL BE THE POTENTIAL FOR A WIDESPREAD FREEZE ACROSS MUCH OF THE HIGHER TERRAIN EARLY THURS WITH SOME AREAS OF FROST POSSIBLE OVER THE NC FOOTHILLS. ON FRIDAY...THE CANADIAN HIGH REINFORCES ITSELF AS IT SLIDES DOWN FROM THE NW AND SETTLES JUST TO OUR WEST AS THE PERIOD ENDS 00Z SAT. THE ATMOSPHERE IS EXPECTED TO BECOME MORE DRY AS THE DAY PROGRESSES AND THE CENTER OF THE HIGH APPROACHES THE AREA. WITH THAT SAID...I DO NOT CARRY ANY SIG POPS AFTER ABOUT 12Z FRI WITH NO QPF BEYOND THAT MORNING. HIGH TEMPS ARE EXPECTED TO REMAIN ABOUT A CATEGORY BELOW THURS MAXES AND THUS...WELL BELOW CLIMATOLOGY FOR LATE OCTOBER. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 200 PM EDT TUESDAY...THE GLOBAL MODELS CONTINUE TO SHOW GOOD GOOD AGREEMENT WITH THE OVERALL SYNOPTIC PATTERN THIS WEEKEND INTO NEXT WEEK. THE DEEP UPPER TROUGH THAT USHERED IN THE UNSEASONABLY COLD WEATHER INTO THE REGION WILL CONTINUE TO MOVE OFF TO THE E-NE THROUGH THE WEEKEND. IN ITS WAKE A A ZONAL WESTERLY UPPER FLOW IS EXPECTED ON SUN AND THEN BECOME SW THE FIRST OF NEXT WEEK AS A DEEP UPPER TROUGH IS CARVED OUT OVER THE ROCKIES...AND WEAK SOUTHERN STREAM SHORT WAVE RIPPLES THROUGH THE DEEP SOUTH. AT THE SURFACE...STRONG CANADIAN HIGH PRESSURE WILL SETTLE OVER THE REGION FRIDAY NIGHT AND BECOME SUPPRESSED TO THE SOUTH OF THE AREA ON SUNDAY AS A WEAK...DRY COLD FRONT MOVES THROUGH THE AREA. HIGH PRESSURE IN THE WAKE OF THE FRONT WILL BUILD OVER THE REGION FROM THE NORTH AND REMAIN RIDGED ACROSS THE AREA THROUGH TUE. THE COLDEST TEMPS OF THIS COLD SPELL WILL OCCUR FRI NIGHT AS THE THE CANADIAN HIGH SETTLES OVER THE REGION ALLOWING FOR IDEAL RADIATIONAL COOLING CONDTIONS. LOWS WILL BE FROM AROUND 30 TO THE LOWER 30S OUTSIDE THE MOUNTAINS....WITH MID TO UPPER 20S MOUNTAIN AREAS. TEMPS WILL MODERATE AFTER THAT AND REACH NEAR NORMAL VALUES ON SUN AND THEN A LITTLE ABOVE NORMAL THE FIRST OF NEXT WEEK. IT SHOULD BE A DRY PERIOD AS HIGH PRESSURE WILL PREDOMINATE. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... AT KCLT...SPRINKLES ARE DISSIPATING AND SHIFTING EAST...SO HAVE LEFT OUT ANY PRECIP MENTION FOR THE START OF THE 00Z TAFS. MID CLOUDS WILL LINGER THRU THE EVENING...WITH ADDITIONAL SPRINKLES POSSIBLE...BUT TOO LOW TO MENTION ANYTHING IN THE TAF. SOME OF THE HIGH RES GUIDANCE...NAMELY THE HRRR AND NARRE-TL...HINT AT SOME PATCHY IFR OR MVFR STRATUS DEVELOPMENT FROM THE MIDLANDS UP THRU PORTIONS OF THE NC PIEDMONT LATER THIS EVENING...THEN DISSIPATING BEFORE DAYBREAK...AS DRY AIR STARTS TO FILTER IN. CONFIDENCE IS JUST TOO LOW TO EVEN HINT AT IT AT THIS TIME. OTHERWISE...VFR THRU THE NIGHT. BY MIDDAY WEDNESDAY...WNW WINDS WILL INCREASE AND BECOME GUSTY. PROBABLY WILL BE PESKY CROSS WIND THRU THE AFTN...WITH GUSTS IN THE 20-25 KT RANGE FREQUENTLY. SKIES SHUD BE MOSTLY CLEAR THO. ELSEWHERE...MID CLOUDS CONTINUE TO LINGER THRU THE EVENING HOURS...WITH A FEW PATCHY SPRINKLES POSSIBLE IN SPOTS. BUT LOW ENUF CHC AND COVERAGE TO LEAVE OUT OF THE TAFS. GUIDANCE AGREES ON ONLY KHKY HAVING MUCH CHC OF ANY VSBY OR CIG RESTRICTIONS...WITH LAKE FOG POSSIBLE OUT OF THE WNW. WINDS WILL INCREASE AND BECOME GUSTY OUT OF THE WEST OR NW BY MIDDAY AT ALL SITES...THEN BEGIN TO SUBSIDE TOWARD 00Z THURSDAY. OUTLOOK...ANOTHER COLD FRONT WILL PASS THROUGH THE AREA THURSDAY. HOWEVER...ANY RESTRICTIONS WILL BE CONFINED TO THE HIGH TERRAIN OF THE NC MOUNTAINS. CONFIDENCE TABLE... 02-08Z 08-14Z 14-20Z 20-02Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .FIRE WEATHER... AS OF 225 PM EDT TUESDAY...MUCH DRIER AIR WILL ENTER THE WESTERN CAROLINAS AND NORTHEAST GEORGIA BEHIND A COLD FRONT WEDNESDAY AFTERNOON. HUMIDITY VALUES ARE EXPECTED TO FALL BETWEEN 25-30 PERCENT OVER THE UPSTATE AND NE GA...WITH SLIGHTLY HIGHER VALUES OVER WESTERN NORTH CAROLINA. AFTERNOON FUEL MOISTURE VALUES HAVE BEEN STEADILY DECREASING OVER THE PAST FEW DAYS. BY MID AFTERNOON WIND GUSTS WILL INCREASE TO 25 MPH. ALL OF THIS WILL LEAD TO A BRIEF PERIOD OF HEIGHTENED FIRE DANGER WEDNESDAY AFTERNOON. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING FOR NCZ033-048>053-058-059-062>065-501-503-505- 507-509. SC...NONE. && $$ SYNOPSIS...JPT NEAR TERM...ARK/MCAVOY SHORT TERM...JPT LONG TERM...LG AVIATION...ARK FIRE WEATHER...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
749 PM EDT TUE OCT 22 2013 .SYNOPSIS... A COLD FRONT WILL GRADUALLY MOVE OFFSHORE TONIGHT WITH A COLD CANADIAN AIR MASS GRADUALLY SETTLING OVER THE REGION ON WEDNESDAY. THIS AIRMASS IS EXPECTED TO LINGER WELL INTO THE WEEKEND AND BRING THE COLDEST TEMPERATURES SO FAR THIS SEASON. && .NEAR TERM /THROUGH WEDNESDAY/... AS OF 745 PM...NO SIGNIFICANT CHANGES NEEDED WITH THIS UPDATE. SPRINKLES/-RA ALMOST COMPLETELY DISSIPATED ACRS THE CHARLOTTE AREA. HOWEVER...MID LVL MOISTURE REMAINS...AND ANOTHER ROUNDS OF LIFT IS WORKING THRU THE AREA WITH THE APPROACHING MID LVL TROF. SO A FEW ADDITIONAL SPRINKLES/-RA MAY DEVELOP...BUT OVERALL I THINK IT WILL BE TOO SPOTTY TO WARRANT MENTIONING IN THE ZONE FCST. AS OF 545 PM...A QUICK UPDATE TO KEEP SLGT CHC POP AND MENTION OF SPRINKLES ACRS THE SE THIRD OF THE CWFA PER RADAR/OBS. THIS ACTIVITY IS SLOWLY SHIFTING TO THE EAST...SO POPS EXIT AROUND 7-8 PM. TEMPS AND DEWPTS WERE ALSO ADJUSTED TO MATCH UP WITH OBS FOR THE NEXT FEW HOURS. THE REST OF THE FCST LEFT UNCHANGED. AS OF 215 PM EDT TUESDAY...WATER VAPOR IMAGERY SHOWS A POTENT SHORT WAVE MOVING ACROSS IOWA ATTM...WITH A BROADER POSITIVELY TILTED WAVE MOVING ACROSS MIDDLE TN AND NRN AL. THE WAVE OVER TN WILL CROSS THE REGION THIS EVENING...INDUCING WEAK CYCLOGENESIS IN THE LEE OF THE SRN APPALACHIANS. THE NAM EVEN HAS SOME RAIN NORTH OF I-40 WITH THE FEATURE LATER TONIGHT. I DID ADD SOME LOW END CHANCE POPS TO THIS AREA BY LATE EVENING TO ACCOUNT FOR THIS. THE NRN STREAM WAVE WILL PUSH A STRONGER FRONT ACROSS THE REGION A LITTLE AFTER 12 UTC ON WED. STRONG COLD ADVECTION AND 35 KT NW FLOW AT 850 MB WILL RESULT IN SHOWERS ALONG THE TN LINE. FREEZING LEVELS WILL BE HIGH THROUGH THE DAY...AND ANY SNOW SHOWER ACTIVITY SHOULD BE CONFINED TO ELEVATIONS ABOVE 5000 FEET. NOT EXPECTING WINDS TO REACH LAKE WIND CRITERIA OVER THE MOUNTAINS...THOUGH THE NRN MTNS COULD BE CLOSE. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... AS OF 2 PM EDT TUESDAY...THE SHORT TERM FCST PICKS UP AT 00Z ON THURSDAY WITH THE BROAD UPPER TROF AXIS JUST TO OUR NORTH AND UPPER RIDGING MAINTAINING ITSELF OVER THE FAR WESTERN CONUS. THE UPPER RIDGE WILL GRADUALLY SHIFT EASTWARD ON FRIDAY AND START TO DEAMPLIFY AS IT MOVES OFFSHORE AND HEIGHTS RISE OVER THE CAROLINAS. ON THURSDAY...COOLER AND DRIER SFC HIGH PRESSURE WILL BE PUSHING INTO THE CWFA AS WE BEGIN THE PERIOD. NWLY TO WLY LOW LVL WINDS WILL PERSIST THROUGHOUT THE DAY WITH MORE OF A WLY COMPONENT EXPECTED DURING THE LATER HALF OF THE DAY/EVENING. MOST OF THE MODEL GUIDANCE INDICATES THAT A LIMITED PLUME OF DEEPER LAYER MOISTURE WILL MOVE ACROSS THE CWFA DURING THE DAY...BUT WILL LIKELY NOT AMOUNT TO MUCH IF ANY PRECIP. THE BEST CHANCES WILL BE CONFINED TO THE NORTHERN MTS AND ALONG THE TENN/NC BORDER. THE MAIN CONCERN WILL BE THE POTENTIAL FOR A WIDESPREAD FREEZE ACROSS MUCH OF THE HIGHER TERRAIN EARLY THURS WITH SOME AREAS OF FROST POSSIBLE OVER THE NC FOOTHILLS. ON FRIDAY...THE CANADIAN HIGH REINFORCES ITSELF AS IT SLIDES DOWN FROM THE NW AND SETTLES JUST TO OUR WEST AS THE PERIOD ENDS 00Z SAT. THE ATMOSPHERE IS EXPECTED TO BECOME MORE DRY AS THE DAY PROGRESSES AND THE CENTER OF THE HIGH APPROACHES THE AREA. WITH THAT SAID...I DO NOT CARRY ANY SIG POPS AFTER ABOUT 12Z FRI WITH NO QPF BEYOND THAT MORNING. HIGH TEMPS ARE EXPECTED TO REMAIN ABOUT A CATEGORY BELOW THURS MAXES AND THUS...WELL BELOW CLIMATOLOGY FOR LATE OCTOBER. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 200 PM EDT TUESDAY...THE GLOBAL MODELS CONTINUE TO SHOW GOOD GOOD AGREEMENT WITH THE OVERALL SYNOPTIC PATTERN THIS WEEKEND INTO NEXT WEEK. THE DEEP UPPER TROUGH THAT USHERED IN THE UNSEASONABLY COLD WEATHER INTO THE REGION WILL CONTINUE TO MOVE OFF TO THE E-NE THROUGH THE WEEKEND. IN ITS WAKE A A ZONAL WESTERLY UPPER FLOW IS EXPECTED ON SUN AND THEN BECOME SW THE FIRST OF NEXT WEEK AS A DEEP UPPER TROUGH IS CARVED OUT OVER THE ROCKIES...AND WEAK SOUTHERN STREAM SHORT WAVE RIPPLES THROUGH THE DEEP SOUTH. AT THE SURFACE...STRONG CANADIAN HIGH PRESSURE WILL SETTLE OVER THE REGION FRIDAY NIGHT AND BECOME SUPPRESSED TO THE SOUTH OF THE AREA ON SUNDAY AS A WEAK...DRY COLD FRONT MOVES THROUGH THE AREA. HIGH PRESSURE IN THE WAKE OF THE FRONT WILL BUILD OVER THE REGION FROM THE NORTH AND REMAIN RIDGED ACROSS THE AREA THROUGH TUE. THE COLDEST TEMPS OF THIS COLD SPELL WILL OCCUR FRI NIGHT AS THE THE CANADIAN HIGH SETTLES OVER THE REGION ALLOWING FOR IDEAL RADIATIONAL COOLING CONDTIONS. LOWS WILL BE FROM AROUND 30 TO THE LOWER 30S OUTSIDE THE MOUNTAINS....WITH MID TO UPPER 20S MOUNTAIN AREAS. TEMPS WILL MODERATE AFTER THAT AND REACH NEAR NORMAL VALUES ON SUN AND THEN A LITTLE ABOVE NORMAL THE FIRST OF NEXT WEEK. IT SHOULD BE A DRY PERIOD AS HIGH PRESSURE WILL PREDOMINATE. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... AT KCLT...SPRINKLES ARE DISSIPATING AND SHIFTING EAST...SO HAVE LEFT OUT ANY PRECIP MENTION FOR THE START OF THE 00Z TAFS. MID CLOUDS WILL LINGER THRU THE EVENING...WITH ADDITIONAL SPRINKLES POSSIBLE...BUT TOO LOW TO MENTION ANYTHING IN THE TAF. SOME OF THE HIGH RES GUIDANCE...NAMELY THE HRRR AND NARRE-TL...HINT AT SOME PATCHY IFR OR MVFR STRATUS DEVELOPMENT FROM THE MIDLANDS UP THRU PORTIONS OF THE NC PIEDMONT LATER THIS EVENING...THEN DISSIPATING BEFORE DAYBREAK...AS DRY AIR STARTS TO FILTER IN. CONFIDENCE IS JUST TOO LOW TO EVEN HINT AT IT AT THIS TIME. OTHERWISE...VFR THRU THE NIGHT. BY MIDDAY WEDNESDAY...WNW WINDS WILL INCREASE AND BECOME GUSTY. PROBABLY WILL BE PESKY CROSS WIND THRU THE AFTN...WITH GUSTS IN THE 20-25 KT RANGE FREQUENTLY. SKIES SHUD BE MOSTLY CLEAR THO. ELSEWHERE...MID CLOUDS CONTINUE TO LINGER THRU THE EVENING HOURS...WITH A FEW PATCHY SPRINKLES POSSIBLE IN SPOTS. BUT LOW ENUF CHC AND COVERAGE TO LEAVE OUT OF THE TAFS. GUIDANCE AGREES ON ONLY KHKY HAVING MUCH CHC OF ANY VSBY OR CIG RESTRICTIONS...WITH LAKE FOG POSSIBLE OUT OF THE WNW. WINDS WILL INCREASE AND BECOME GUSTY OUT OF THE WEST OR NW BY MIDDAY AT ALL SITES...THEN BEGIN TO SUBSIDE TOWARD 00Z THURSDAY. OUTLOOK...ANOTHER COLD FRONT WILL PASS THROUGH THE AREA THURSDAY. HOWEVER...ANY RESTRICTIONS WILL BE CONFINED TO THE HIGH TERRAIN OF THE NC MOUNTAINS. CONFIDENCE TABLE... 23-05Z 05-11Z 11-17Z 17-23Z KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 92% HIGH 85% HIGH 100% KHKY HIGH 100% HIGH 100% HIGH 92% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .FIRE WEATHER... AS OF 225 PM EDT TUESDAY...MUCH DRIER AIR WILL ENTER THE WESTERN CAROLINAS AND NORTHEAST GEORGIA BEHIND A COLD FRONT WEDNESDAY AFTERNOON. HUMIDITY VALUES ARE EXPECTED TO FALL BETWEEN 25-30 PERCENT OVER THE UPSTATE AND NE GA...WITH SLIGHTLY HIGHER VALUES OVER WESTERN NORTH CAROLINA. AFTERNOON FUEL MOISTURE VALUES HAVE BEEN STEADILY DECREASING OVER THE PAST FEW DAYS. BY MID AFTERNOON WIND GUSTS WILL INCREASE TO 25 MPH. ALL OF THIS WILL LEAD TO A BRIEF PERIOD OF HEIGHTENED FIRE DANGER WEDNESDAY AFTERNOON. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY MORNING FOR NCZ033-048>053-058-059-062>065-501-503-505- 507-509. SC...NONE. && $$ SYNOPSIS...JPT NEAR TERM...ARK/MCAVOY SHORT TERM...JPT LONG TERM...LG AVIATION...ARK FIRE WEATHER...MCAVOY
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.

&& .PREVIOUS DISCUSSION... .SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT THE OVERALL FLOW PATTERN DOESNT CHANGE MUCH THROUGH THE NEXT COUPLE DAYS. HOWEVER THAT SAID A DRYING TREND WILL ENSUE LATER THIS WEEK. FOR TNT ANOTHER FAST MOVING CLIPPER LIKE SYSTEM WILL DROP SOUTHEAST OVER THE REGION. THE LATEST MODEL RUNS ARE SLOWER AND FURTHER WEST WITH THIS SYSTEM VS PREVIOUS RUNS. ONCE AGAIN DECENT UVM WILL COMBINE WITH SUFFICIENT MOISTURE TO PRODUCE FAIRLY WIDESPREAD PCPN. AGAIN TNT PARTIAL THICKNESS/BUFR SOUNDINGS POINT TO A MIX OF PCPN TYPES...PARTICULARLY EAST OF THE MO RVR VALLEY. THE MIX OF PCPN WILL PROBABLY KEEP ANY ACCUMULATIONS FAIRLY MINIMAL...PERHAPS UP TO AN INCH IN GRASSY AREAS. THE PCPN MAY WELL LINGER THROUGH WEDNESDAY MORNING GIVEN LATEST GFS/ECMWF PROGS...BUT SHOULD CHANGE BACK OVER TO MOSTLY RAIN. FOR WEDNESDAY NIGHT THROUGH THURSDAY NIGHT WE ARE LOOKING AT MAINLY DRY CONDITIONS...WITH ONLY SLOWLY IMPROVING TEMPERATURES THROUGH THE PERIOD. .LONG TERM...FRIDAY THROUGH TUESDAY THERE IS A REASONABLE AGREEMENT BETWEEN THE 0Z ECMWF AND THE 12Z GFS THROUGH MOST OF THE LONG TERM PORTION OF THE FORECAST. THE PERIOD BEGINS WITH A CLIPPER SYSTEM PASSING WELL NORTH AND EAST OF THE REGION. THIS SYSTEM WILL DRAW WARMER AIR INTO THE REGION WITH TEMPERATURES WARMING TO AROUND NORMAL FOR THE WEEKEND. TOWARDS THE END OF THE WEEKEND...BOTH MODELS SHOW AN UPPER LEVEL TROUGH DIGGING ALONG THE WEST COAST. THIS UPPER LEVEL TROUGH...ALONG WITH A SURFACE LOW PRESSURE OVER THE FRONT RANGE OF THE ROCKIES WILL BRING CHANCES FOR PRECIPITATION INTO THE AREA FOR MONDAY AND TUESDAY. THERMAL PROFILES APPEAR COLD ENOUGH FOR ACCUMULATING SNOWFALL OVER THE WESTERN CWA. SINCE THIS EVENT IS STILL A WEEK AWAY...WILL NOT GET TOO EXCITED ABOUT THE DETAILS YET. && .AVIATION... 00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS A FAST MOVING AREA OF LOW PRESSURE WILL TRACK SOUTHEASTWARD ACROSS THE REGION LATE TONIGHT AND ON INTO THE DAY ON WEDNESDAY. THIS SYSTEM WILL BRING LIGHT PRECIPITATION TO THE KPIR/KMBG TERMINALS...WHILE PROBABILITIES ARE A BIT LOWER FOR SEEING PRECIPITATION REACH ALL THE WAY OVER TO THE KABR/KATY TERMINALS. THERMAL PROFILES SUGGEST P-TYPE AT KPIR SHOULD STAY RAIN DURING THIS EVENT...WHILE P-TYPE AT KMBG COULD START OUT AS RAIN BUT WILL LIKELY CHANGE-OVER TO SNOW BEFORE 12Z WEDNESDAY. IF PRECIPITATION MAKES IT ALL THE WAY INTO THE KABR/KATY TERMINALS...P-TYPE THERE SHOULD BE SNOW. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...DORN SHORT TERM...TDK LONG TERM...SD AVIATION...DORN WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
825 PM CDT TUE OCT 22 2013 .UPDATE... COLD FRONT AND ASSOCIATED LINE OF SHOWERS CURRENTLY RACING SOUTHEAST ACROSS SOUTHERN ILLINOIS AND WESTERN KENTUCKY PER RADAR IMAGERY. LATEST HRRR AND 12KM WRF MODELS BOTH BRING LINE OF SHOWERS INTO THE CWA IN A FEW HOURS BUT WEAKEN THE LINE AS IT MOVES THROUGH THE MID STATE. NEVERTHELESS...BASED ON RADAR TRENDS WILL HAVE TO BUMP UP POPS TO SLIGHT/LOW CHANCE OVER THE NORTHERN HALF...ESPECIALLY NORTHWEST ZONES. FURTHER UPDATES TO FORECAST ARE POSSIBLE THIS EVENING IF IT APPEARS LIGHT RAIN WILL BE MORE WIDESPREAD. IN ADDITION...SHARP PRESSURE RISE BEHIND FRONT IS RESULTING IN A BRIEF PERIOD OF GUSTY WINDS OF 20-30 KTS AS NOTED ON SURFACE OBS SUCH AS KCGI. DUE TO THE BRIEF DURATION OF THESE GUSTIER WINDS...WILL NOT MENTION EXPLICITLY IN GRIDS/ZONES. ALSO ADJUSTED CLOUD COVER AND OTHER GRIDS BASED ON LATEST OBS. SHAMBURGER && .PREV DISCUSSION... /ISSUED 820 PM CDT TUE OCT 22 2013/ UPDATE...FOR 00Z TAFS... AVIATION... LOW PRESSURE CENTERED OVER SOUTHERN ILLINOIS WILL PUSH A NARROW SLOW MOVING BAND OF CLOUDS ACROSS THE NORTHERN PORTION OF MIDDLE TENNESSEE THIS EVENING. A FEW SHOWERS LOCATED OVER SOUTHEASTERN MISSOURI EXPECTED TO WEAKEN BEFORE ENTERING MIDDLE TENNESSEE... HOWEVER WINDS EXPECTED TO STAY STEADY AROUND 08 KNOTS THROUGHOUT THE NIGHT AND INTO WEDNESDAY AS THE WEAK FRONT ASSOCIATED WITH THE PREVIOUSLY MENTIONED SHOWERS PUSHES THROUGH THE AREA. MAINLY VFR BKN TO OVC CONDITIONS AT ALL SITES WITH CIGS OCCASIONALLY FALLING TO 3000 FT AFTER 03Z AT CSV. SKIES BECOME SCATTERED TO CLEAR DURING THE DAY ON WEDNESDAY AS THE LOW PRESSURE SYSTEM MOVES EAST. PREV DISCUSSION... /ISSUED 237 PM CDT TUE OCT 22 2013/ SHORT TERM...AT 2PM THIS AFTERNOON, A COLD FRONT STRETCHED FROM JUST NORTH OF MUSCLE SHOALS, ALABAMA TO JUST NORTH OF CROSSVILLE, TENNESSEE. A BAND OF CLOUDS, ASSOCIATED WITH THE FRONT, COVERED MUCH OF EASTERN AND SOUTHERN MIDDLE TENNESSEE WITH THE BACK EDGE OF THE BKN-TO-OVC CLOUDS LOCATED NEAR A LAWRENCEBURG TO CELINA LINE. AT 2PM...TEMPERATURES RANGED FROM NEAR 60 DEGREES IN THE SUNNY NORTHWEST TO NEAR 50 IN THE CLOUDIER SECTIONS OF THE UPPER CUMBERLAND. EVEN THOUGH CLOUDS SHOULD CONTINUE CLEARING FROM THE WEST, THEY PROBABLY WON`T CLEAR FAST ENOUGH ALONG THE UPPER CUMBERLAND TO ALLOW FOR HIGH TEMPERATURES TO PUSH MUCH MORE THAN A FEW DEGS ABOVE WHAT THEY ARE RIGHT NOW. STILL LOOKS LIKE A COLD FRONT WILL SWEEP ACROSS THE AREA TONIGHT, WITH AN AREA OF BKN STRATOCU LIKELY TO PUSH ACROSS NORTHERN AND EASTERN SECTIONS OF THE MID STATE, AS THE SURFACE LOW ZIPS FROM NORTHERN MISSOURI THIS AFTERNOON TO EASTERN KENTUCKY BY LATE TONIGHT. SINCE OUR ATMOSPHERE SHOULD REMAIN PRETTY DRY, LOOK FOR ONLY A SLIGHT CHANCE FOR SHOWERS OVER THE NORTH TONIGHT AND WEDNESDAY MORNING, MAINLY IN AREAS NEAR THE KENTUCKY LINE. DON`T LOOK FOR MUCH MORE THAN A 10 TO 15 DEG TEMPERATURE RISE DURING THE DAYLIGHT HOURS ON WEDNESDAY, WITH AFTERNOON HIGHS MAINLY BETWEEN 50 AND 55 DEGREES. ALONG WITH SOME FRESH NORTHWEST BREEZES AT 10 TO 15 MPH, THOSE TEMPERATURES SHOULD FEEL PRETTY DOGGONE CHILLY--ESPECIALLY CONSIDERING THE FACT THAT OUR TEMPERATURES WILL BE AVERAGING SOME 15 DEGREES BELOW NORMAL TOMORROW. THE STRONGEST COLD AIR OUTBREAK OF THE SEASON WILL ARRIVE, FRESH OUT OF CANADA, ON THURSDAY AND LINGER INTO SATURDAY MORNING, WITH MID STATE LOW TEMPERATURES LIKELY TO AVERAGE SOME 15 TO 20 DEGREES BELOW NORMAL BY FRIDAY MORNING AND SATURDAY MORNING. NIGHTTIME FREEZING TEMPERATURES WILL BECOME INCREASINGLY LIKELY LATE THIS WEEK, WITH WIDESPREAD FREEZING TEMPERATURES AND WIDESPREAD FROST EXPECTED OVER THE AREA SATURDAY MORNING, AND EVEN THE POSSIBILITY OF A HARD KILLING FREEZE IN SOME AREAS (ESPECIALLY ALONG THE CUMBERLAND PLATEAU). AS A RESULT, WILL UPDATE THE HWO TO GO WITH A FREEZE OUTLOOK FOR LATE WEEK, AND WOULDN`T BE SURPRISED IF WE NEED TO ISSUE A FREEZE WATCH SOMETIME OVER THE NEXT 24 HRS. THE LOW TEMPERATURE AT NASHVILLE IS FORECAST TO HIT 32 DEGREES FRIDAY MORNING, AND THEN SINK TO 30 DEGREES SATURDAY MORNING. THE NORMALLY COLDER OUTLYING AREAS WILL PROBABLY SEE LOWS SATURDAY MORNING IN THE MIDDLE AND UPPER 20S! LONG TERM...AFTER THE LATE WEEK COLD SNAP, LOOK FOR AT LEAST A TEMPORARY TURN TO MILDER CONDITIONS, WITH UPPER FLOW BY EARLY NEXT WEEK BECOMING MORE ZONAL. AS A RESULT, EXPECT HIGH TEMPS TO FINALLY PUSH CLOSER TO NORMAL AND BE UP AROUND 70 AT NASHVILLE BY NEXT MONDAY AND TUESDAY. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
317 PM CDT MON OCT 21 2013 .SHORT TERM...SATELLITE PICS SHOWED CLOUDS INCREASING OVER SOUTHERN MIDDLE TENNESSEE THIS AFTERNOON, AS WELL AS OVER THE EXTREME NORTHWEST. BIG BULGE OF 300-500MB MOISTURE LIFTING NORTHWARD FROM GULF COASTAL REGION, AHEAD OF MISSISSIPPI VALLEY SHORTWAVE, WAS RESPONSIBLE FOR THE INCREASE IN CLOUDS OVER THE SOUTH. MEANWHILE, A BAND OF INCREASED 850-700MB MOISTURE, IMMEDIATELY AHEAD OF THE SHORTWAVE WAS PRODUCING THE INCREASED CLOUDS OVER THE EXTREME NORTHWEST. SURFACE COLD FRONT, THAT WAS PUSHING INTO THE MISSOURI BOOTHEEL AT MID-AFTERNOON, WAS CREATING A BAND OF SHOWERS, EXTENDING FROM EASTERN OKLAHOMA AND NORTHWEST ARKANSAS UP ACROSS SOUTHERN PARTS OF MISSOURI. THIS COLD AND BAND OF RAIN IS EXPECTED TO PUSH EASTWARD OVERNIGHT INTO MIDDLE TENNESSEE, AND BOTH THE HRRR BRINGS THIS BAND OF LIGHT RAIN INTO AT LEAST NORTHWESTERN AND NORTH-CENTRAL PARTS OF OUR FA BY 12Z TUE. EVEN THOUGH PRECIP TOTALS WILL BE LIGHT WITH THIS NEXT COLD FRONT, BELIEVE AN INCREASE TO "LIKELY POPS" IS WARRANTED OVER MOST NORTHERN AREAS TONIGHT AND TUESDAY. WILL GO WITH A CHANCE OF SHOWERS ELSEWHERE. EXPECT FRONT TO BE NEAR A LAFAYETTE-NASHVILLE-WAYNESBORO LINE AT 06Z AND THEN PUSH TO THE CUMBERLAND PLATEAY BY 12-14Z. EXPECT POST-FRONTAL SHOWERS TO END OVER EASTERN AREAS BY 18Z TUE. SURFACE DEW POINTS DON`T DRY OUT MUCH UNTIL PASSAGE OF ANOTHER COLD FRONT TUESDAY NIGHT...WHICH WILL SEND DEW POINTS TUMBLING INTO THE UPPER 20S BY WEDNESDAY AFTERNOON. THERE MAY BE A FEW LIGHT SHOWERS OVER NORTH-CENTRAL AND NORTHEASTERN PARTS OF THE MID STATE TUESDAY NIGHT AND WEDNESDAY MORNING AS THIS FRONT PASSES THROUGH. HIGHS ON WEDNESDAY AREN`T EXPECTED TO EVEN GET OUT OF THE 50S! STILL LOOKS THE COLD AND DRY CANADIAN AIR MASS THAT COMES IN WEDNESDAY, WILL KEEP DEW POINTS LOW ENOUGH TO PRODUCE THE LIKELIHOOD FOR SOME FROST AND FREEZING TEMPERATURES OVER MUCH OF THE MID STATE DURING LATE WEEK...ESPECIALLY DURING THE EARLY MORNING HOURS ON FRIDAY AND SATURDAY. A HARD FREEZE (I.E., TEMPS OF AOB 27 DEGS) MAY EVEN OCCUR ALONG THE CUMBERLAND PLATEAU SATURDAY MORNING. NASHVILLE MAY EVEN FLIRT WITH THE 32 DEG MARK THAT SAME MORNING. .LONG TERM...LOOKS LIKE OUR CHILLY WEATHER PATTERN MAY RELAX JUST A BIT EARLY NEXT WEEK, WITH UPPER FLOW BECOMING A BIT MORE ZONAL AND AFTERNOON HIGHS PERHAPS STARTING TO FLIRT WITH THE 70 DEG MARK OVER SOME SOUTHERN AND WESTERN COUNTIES BY NEXT MONDAY. && .PRELIMINARY POINT TEMPS/POPS... NASHVILLE 46 62 41 52 / 40 50 10 10 CLARKSVILLE 44 62 38 53 / 70 10 20 05 CROSSVILLE 42 60 39 50 / 20 50 20 10 COLUMBIA 46 65 41 54 / 20 30 10 05 LAWRENCEBURG 44 67 41 55 / 20 20 10 05 WAVERLY 44 63 38 53 / 70 20 10 05 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 19
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1215 PM CDT MON OCT 21 2013 .DISCUSSION... SEE 18Z AVIATION DISCUSSION. && .AVIATION... GUIDANCE IS NOT IN THE BEST AGREEMENT THIS AFTN. THE RAP IS AGGRESSIVE WITH RAIN CHANCES THIS AFTN WHILE GLOBAL MODELS LOOK RATHER BENIGN. WILL CONTINUE TO CARRY VCSH AS PWATS REMAIN AROUND 1.5 INCHES AND LIFT ON THE LEADING EDGE OF A 700 MB TROF AXIS HEADS THIS WAY. A COLD FRONT WILL CROSS THE AREA LATE TONIGHT BUT BOTH THE GFS/NAM HINT AT BRIEF IFR CIGS JUST BEFORE SUNRISE. WILL HINT AT THAT IN THE TAF WITH A SCT008 GROUP. SKIES WILL CLEAR RAPIDLY TUESDAY MORNING WITH VFR CONDS EXPECTED. WINDS WILL BE GUSTY IN THE MORNING WITH THE GRADIENT WEAKENING IN THE AFTN. 43 && .PREV DISCUSSION... /ISSUED 1000 AM CDT MON OCT 21 2013/ UPDATE... WIDESPREAD SOUTHERN CWA SHOWERS...WITH OCCASIONAL THUNDER...MOVING QUICKLY NORTHEAST AT AROUND 40 MPH. THE BULK OF TODAY`S PRECIPITATION WILL FALL ALONG AND SOUTH OF HIGHWAY 59...OR WHERE THE MOST EFFICIENT UPPER LEVEL FORCING RESIDES. THE UPPER TEXAS COAST FALLING IN THE RRQ OF A SOUTHEASTERN U.S. 3H JET WITH A DISTURBANCE RIDING UP AHEAD OF A CENTRAL TEXAS SHORTWAVE TROUGH. ADDITIONAL CONVECTIVE FOCUS IS BEING PROVIDED BY A NEAR-STATIONARY WARM FRONTAL BOUNDARY ALONG THE COAST. THIS EVENING INTO EARLY TUESDAY MORNING`S COLD FRONTAL PASSAGE ON SCHEDULE TO PASS OVER THE NORTHERN FA TONIGHT...TO THE COAST BEFORE SUNRISE TOMORROW. PARTIALLY TO MOSTLY OVERCAST WITH RAIN/ISOLATED STORMS PRIMARILY CONFINED TO SOUTHERN THIRD OF REGION TODAY...TEMPERATURES WILL CLIMB INTO THE AVERAGE UPPER 70S BY 4 PM. POST-FRONTAL COOLER AND MUCH DRIER CONDITIONS TOMORROW...INLAND MORNING MINIMUMS IN THE 50S (60S COAST)...WARMING INTO THE VERY COMFORTABLE MID 70S. 31 PREV DISCUSSION... /ISSUED 636 AM CDT MON OCT 21 2013/ DISCUSSION... SEE AVIATION FOR 12Z TAF DISCUSSION AVIATION... LIGHT SHRA TO THE WEST OF THE TERMINALS THIS MORNING ASSOCIATED WITH A WEAK SHORTWAVE DISTURBANCE OVER SAT. EXPECT SHRA COVERAGE TO INCREASE BY LATE MORNING AS UPPER DISTURBANCE MOVES OVERHEAD. A COLD FRONT CURRENTLY STRETCHING FROM NEAR FST-SPS-TUL WILL APPROACH THE REGION TODAY REACHING CLL BY 03Z TUESDAY AND THE METRO TERMINALS BETWEEN 08-10Z. A BRIEF PERIOD OF MVFR CIGS IS POSSIBLE AS THE FRONT PASSES THROUGH THE REGION...CLEARING THE COAST AT THE END OF THE CURRENT TAF PERIOD. 38 PREV DISCUSSION... /ISSUED 442 AM CDT MON OCT 21 2013/ DISCUSSION... BASED ON 00Z UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY...FIRST OF A COUPLE OF SHORT WAVE TROUGHS IS AFFECTING SE TX THIS MORNING. UPWARD VERTICAL MOTION FROM THE FIRST SHORTWAVE IS SUPPORTING CONVECTION BETWEEN VICTORIA AND WHARTON THIS MORNING ON RADAR IMAGERY. ALSO GETTING QUITE A BIT OF CONVECTION TO DEVELOP OFF THE LOWER TX COAST AND S TX. SECOND MORE SIGNIFICANT TROUGH AXIS IS BACK OVER THE S ROCKIES AND SHOULD BE PUSHING THROUGH LATER TODAY AND TONIGHT AS IT SHEARS OUT. JET STEAM IS ALSO EXPECTED TO BECOME MORE FAVORABLE FOR UPWARD MOTION AS IT STRENGTHENS OVER THE MID SOUTH AND POSITIONS DIVERGENCE OVER SE TX FROM RIGHT ENTRANCE REGION OF THE JET. EXPECT THERE TO BE SOME ISENTROPIC LIFT AS WELL FROM DISSIPATING FRONTAL BOUNDARY IN THE GULF. ALL OF THIS SHOULD SUPPORT SOME RAINFALL ACROSS THE SOUTHERN PORTION OF SE TX AND ALONG THE COAST. THE 06Z HRRR AND 00Z TX TECH WRF KEEP MOST OF THE PRECIP OFF THE COAST AND HAVE ORIENTED POPS AS SUCH. POPS MAY BE ABOUT 10 PERCENT TOO HIGH ACROSS THE BOARD FOR INLAND AREAS BUT THINK THAT MOST AREAS WILL SEE AT LEAST SOME RAIN...JUST LOWER AMOUNTS. LOOKS LIKE THE COASTAL COUNTIES WILL LIKELY HAVE MAYBE 0.25-0.5 INCHES OF RAIN. AN 1 INCH TOTALS WILL BE OUT IN THE GULF. THE REST OF SE TX LIKELY HAVE A TENTH OF AN INCH IF THAT. DESPITE CLOUD COVER STILL THINK MAX TEMPS IN THE UPPER 70S LOOK GOOD WITH MOISTURE AND WARM ADVECTION IN PLACE TODAY. COLD FRONT CURRENTLY WORKING THROUGH OKLA AND W TX WILL PUSH INTO SE TX TONIGHT AND OFF THE COAST BY 12Z TUE. THIS SHOULD END ANY RAIN CHANCES FOR SE TX WITH THE BULK OF THE PRECIP IN THE GULF HEADED TOWARDS N GULF COAST. COLD ADVECTION DURING THE DAY SHOULD KEEP MAX TEMPS IN THE MID 70S ALONG THE COAST AND LOW 70S FARTHER INLAND. HIGH PRESSURE WILL BUILD OVER SE TX FOR WED MORNING SO EXPECT MIN TEMPS BACK IN THE UPPER 40S TO LOW 50S. NEAR TO BELOW NORMAL TEMPERATURES ARE LIKELY TO CONTINUE THE REST OF THE WEEK. UPPER LEVEL PATTERN SHOULD BE QUITE AMPLIFIED WITH LONG WAVE TROUGH OVER THE GREAT LAKES AND NW FLOW ACROSS THE PLAINS DUE TO RIDGING OVER THE WEST COAST. SHORT WAVE TROUGH STILL EXPECTED TO IMPACT N TX THROUGH SE TX ON SATURDAY BUT LOOKS MUCH WEAKER. MOISTURE WILL ALSO BE LIMITED SO BACKED OFF ON POPS SOME BUT KEPT A PERIOD OF 20 POPS FOR NORTHERN AREAS OF SE TX WHERE LIFT MAY BE MAXIMIZED. OTHERWISE FORECAST SHOULD BE DRY THROUGH THE WEEKEND. TEMPERATURES WERE NOT ADJUSTED VERY MUCH BUT DID TREND TEMPS COOLER FOR THE WEEKEND. ANOTHER AREA OF HIGH PRESSURE WILL BUILD OVER THE MISS RIVER VALLEY WITH NE/E BOUNDARY LAYER FLOW OVER SE TX. THIS SHOULD ALLOW FOR COOLER AIR TO FILTER INTO THE REGION FOR THE WEEKEND. THIS WILL LIKELY KEEP TEMPS NEAR NORMAL OR EVEN A DEGREE OR TWO BELOW NORMAL. 39 MARINE... ONSHORE FLOW THIS MORNING WILL PERSIST THROUGH THE DAY AHEAD OF A COLD FRONT WHICH WILL PUSH OFFSHORE JUST BEFORE DAYBREAK ON TUESDAY. CAUTION FLAGS WILL BE NEEDED IN THE WAKE OF THE FRONT WITH ADVISORY CONDITIONS POSSIBLE FOR A BRIEF PERIOD ON TUESDAY. EXPECT BRISK NORTH AND NORTHEAST WINDS THROUGH THE END OF THE WEEK WITH CAUTION FLAGS POSSIBLE FOR MOST OF THE WEEK. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 78 53 73 51 77 / 20 20 10 10 10 HOUSTON (IAH) 80 59 75 52 78 / 50 20 10 10 10 GALVESTON (GLS) 79 66 76 62 77 / 90 40 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...31 AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1000 AM CDT MON OCT 21 2013 .UPDATE... WIDESPREAD SOUTHERN CWA SHOWERS...WITH OCCASIONAL THUNDER...MOVING QUICKLY NORTHEAST AT AROUND 40 MPH. THE BULK OF TODAY`S PRECIPITATION WILL FALL ALONG AND SOUTH OF HIGHWAY 59...OR WHERE THE MOST EFFICIENT UPPER LEVEL FORCING RESIDES. THE UPPER TEXAS COAST FALLING IN THE RRQ OF A SOUTHEASTERN U.S. 3H JET WITH A DISTURBANCE RIDING UP AHEAD OF A CENTRAL TEXAS SHORTWAVE TROUGH. ADDITIONAL CONVECTIVE FOCUS IS BEING PROVIDED BY A NEAR-STATIONARY WARM FRONTAL BOUNDARY ALONG THE COAST. THIS EVENING INTO EARLY TUESDAY MORNING`S COLD FRONTAL PASSAGE ON SCHEDULE TO PASS OVER THE NORTHERN FA TONIGHT...TO THE COAST BEFORE SUNRISE TOMORROW. PARTIALLY TO MOSTLY OVERCAST WITH RAIN/ISOLATED STORMS PRIMARILY CONFINED TO SOUTHERN THIRD OF REGION TODAY...TEMPERATURES WILL CLIMB INTO THE AVERAGE UPPER 70S BY 4 PM. POST-FRONTAL COOLER AND MUCH DRIER CONDITIONS TOMORROW...INLAND MORNING MINIMUMS IN THE 50S (60S COAST)...WARMING INTO THE VERY COMFORTABLE MID 70S. 31 && .PREV DISCUSSION... /ISSUED 636 AM CDT MON OCT 21 2013/ DISCUSSION... SEE AVIATION FOR 12Z TAF DISCUSSION AVIATION... LIGHT SHRA TO THE WEST OF THE TERMINALS THIS MORNING ASSOCIATED WITH A WEAK SHORTWAVE DISTURBANCE OVER SAT. EXPECT SHRA COVERAGE TO INCREASE BY LATE MORNING AS UPPER DISTURBANCE MOVES OVERHEAD. A COLD FRONT CURRENTLY STRETCHING FROM NEAR FST-SPS-TUL WILL APPROACH THE REGION TODAY REACHING CLL BY 03Z TUESDAY AND THE METRO TERMINALS BETWEEN 08-10Z. A BRIEF PERIOD OF MVFR CIGS IS POSSIBLE AS THE FRONT PASSES THROUGH THE REGION...CLEARING THE COAST AT THE END OF THE CURRENT TAF PERIOD. 38 PREV DISCUSSION... /ISSUED 442 AM CDT MON OCT 21 2013/ DISCUSSION... BASED ON 00Z UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY...FIRST OF A COUPLE OF SHORT WAVE TROUGHS IS AFFECTING SE TX THIS MORNING. UPWARD VERTICAL MOTION FROM THE FIRST SHORTWAVE IS SUPPORTING CONVECTION BETWEEN VICTORIA AND WHARTON THIS MORNING ON RADAR IMAGERY. ALSO GETTING QUITE A BIT OF CONVECTION TO DEVELOP OFF THE LOWER TX COAST AND S TX. SECOND MORE SIGNIFICANT TROUGH AXIS IS BACK OVER THE S ROCKIES AND SHOULD BE PUSHING THROUGH LATER TODAY AND TONIGHT AS IT SHEARS OUT. JET STEAM IS ALSO EXPECTED TO BECOME MORE FAVORABLE FOR UPWARD MOTION AS IT STRENGTHENS OVER THE MID SOUTH AND POSITIONS DIVERGENCE OVER SE TX FROM RIGHT ENTRANCE REGION OF THE JET. EXPECT THERE TO BE SOME ISENTROPIC LIFT AS WELL FROM DISSIPATING FRONTAL BOUNDARY IN THE GULF. ALL OF THIS SHOULD SUPPORT SOME RAINFALL ACROSS THE SOUTHERN PORTION OF SE TX AND ALONG THE COAST. THE 06Z HRRR AND 00Z TX TECH WRF KEEP MOST OF THE PRECIP OFF THE COAST AND HAVE ORIENTED POPS AS SUCH. POPS MAY BE ABOUT 10 PERCENT TOO HIGH ACROSS THE BOARD FOR INLAND AREAS BUT THINK THAT MOST AREAS WILL SEE AT LEAST SOME RAIN...JUST LOWER AMOUNTS. LOOKS LIKE THE COASTAL COUNTIES WILL LIKELY HAVE MAYBE 0.25-0.5 INCHES OF RAIN. AN 1 INCH TOTALS WILL BE OUT IN THE GULF. THE REST OF SE TX LIKELY HAVE A TENTH OF AN INCH IF THAT. DESPITE CLOUD COVER STILL THINK MAX TEMPS IN THE UPPER 70S LOOK GOOD WITH MOISTURE AND WARM ADVECTION IN PLACE TODAY. COLD FRONT CURRENTLY WORKING THROUGH OKLA AND W TX WILL PUSH INTO SE TX TONIGHT AND OFF THE COAST BY 12Z TUE. THIS SHOULD END ANY RAIN CHANCES FOR SE TX WITH THE BULK OF THE PRECIP IN THE GULF HEADED TOWARDS N GULF COAST. COLD ADVECTION DURING THE DAY SHOULD KEEP MAX TEMPS IN THE MID 70S ALONG THE COAST AND LOW 70S FARTHER INLAND. HIGH PRESSURE WILL BUILD OVER SE TX FOR WED MORNING SO EXPECT MIN TEMPS BACK IN THE UPPER 40S TO LOW 50S. NEAR TO BELOW NORMAL TEMPERATURES ARE LIKELY TO CONTINUE THE REST OF THE WEEK. UPPER LEVEL PATTERN SHOULD BE QUITE AMPLIFIED WITH LONG WAVE TROUGH OVER THE GREAT LAKES AND NW FLOW ACROSS THE PLAINS DUE TO RIDGING OVER THE WEST COAST. SHORT WAVE TROUGH STILL EXPECTED TO IMPACT N TX THROUGH SE TX ON SATURDAY BUT LOOKS MUCH WEAKER. MOISTURE WILL ALSO BE LIMITED SO BACKED OFF ON POPS SOME BUT KEPT A PERIOD OF 20 POPS FOR NORTHERN AREAS OF SE TX WHERE LIFT MAY BE MAXIMIZED. OTHERWISE FORECAST SHOULD BE DRY THROUGH THE WEEKEND. TEMPERATURES WERE NOT ADJUSTED VERY MUCH BUT DID TREND TEMPS COOLER FOR THE WEEKEND. ANOTHER AREA OF HIGH PRESSURE WILL BUILD OVER THE MISS RIVER VALLEY WITH NE/E BOUNDARY LAYER FLOW OVER SE TX. THIS SHOULD ALLOW FOR COOLER AIR TO FILTER INTO THE REGION FOR THE WEEKEND. THIS WILL LIKELY KEEP TEMPS NEAR NORMAL OR EVEN A DEGREE OR TWO BELOW NORMAL. 39 MARINE... ONSHORE FLOW THIS MORNING WILL PERSIST THROUGH THE DAY AHEAD OF A COLD FRONT WHICH WILL PUSH OFFSHORE JUST BEFORE DAYBREAK ON TUESDAY. CAUTION FLAGS WILL BE NEEDED IN THE WAKE OF THE FRONT WITH ADVISORY CONDITIONS POSSIBLE FOR A BRIEF PERIOD ON TUESDAY. EXPECT BRISK NORTH AND NORTHEAST WINDS THROUGH THE END OF THE WEEK WITH CAUTION FLAGS POSSIBLE FOR MOST OF THE WEEK. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 78 53 73 51 77 / 20 20 10 10 10 HOUSTON (IAH) 80 59 75 52 78 / 50 20 10 10 10 GALVESTON (GLS) 79 66 76 62 77 / 90 40 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...31/43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
636 AM CDT MON OCT 21 2013 .DISCUSSION... SEE AVIATION FOR 12Z TAF DISCUSSION && .AVIATION... LIGHT SHRA TO THE WEST OF THE TERMINALS THIS MORNING ASSOCIATED WITH A WEAK SHORTWAVE DISTURBANCE OVER SAT. EXPECT SHRA COVERAGE TO INCREASE BY LATE MORNING AS UPPER DISTURBANCE MOVES OVERHEAD. A COLD FRONT CURRENTLY STRETCHING FROM NEAR FST-SPS-TUL WILL APPROACH THE REGION TODAY REACHING CLL BY 03Z TUESDAY AND THE METRO TERMINALS BETWEEN 08-10Z. A BRIEF PERIOD OF MVFR CIGS IS POSSIBLE AS THE FRONT PASSES THROUGH THE REGION...CLEARING THE COAST AT THE END OF THE CURRENT TAF PERIOD. 38 && .PREV DISCUSSION... /ISSUED 442 AM CDT MON OCT 21 2013/ DISCUSSION... BASED ON 00Z UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY...FIRST OF A COUPLE OF SHORT WAVE TROUGHS IS AFFECTING SE TX THIS MORNING. UPWARD VERTICAL MOTION FROM THE FIRST SHORTWAVE IS SUPPORTING CONVECTION BETWEEN VICTORIA AND WHARTON THIS MORNING ON RADAR IMAGERY. ALSO GETTING QUITE A BIT OF CONVECTION TO DEVELOP OFF THE LOWER TX COAST AND S TX. SECOND MORE SIGNIFICANT TROUGH AXIS IS BACK OVER THE S ROCKIES AND SHOULD BE PUSHING THROUGH LATER TODAY AND TONIGHT AS IT SHEARS OUT. JET STEAM IS ALSO EXPECTED TO BECOME MORE FAVORABLE FOR UPWARD MOTION AS IT STRENGTHENS OVER THE MID SOUTH AND POSITIONS DIVERGENCE OVER SE TX FROM RIGHT ENTRANCE REGION OF THE JET. EXPECT THERE TO BE SOME ISENTROPIC LIFT AS WELL FROM DISSIPATING FRONTAL BOUNDARY IN THE GULF. ALL OF THIS SHOULD SUPPORT SOME RAINFALL ACROSS THE SOUTHERN PORTION OF SE TX AND ALONG THE COAST. THE 06Z HRRR AND 00Z TX TECH WRF KEEP MOST OF THE PRECIP OFF THE COAST AND HAVE ORIENTED POPS AS SUCH. POPS MAY BE ABOUT 10 PERCENT TOO HIGH ACROSS THE BOARD FOR INLAND AREAS BUT THINK THAT MOST AREAS WILL SEE AT LEAST SOME RAIN...JUST LOWER AMOUNTS. LOOKS LIKE THE COASTAL COUNTIES WILL LIKELY HAVE MAYBE 0.25-0.5 INCHES OF RAIN. AN 1 INCH TOTALS WILL BE OUT IN THE GULF. THE REST OF SE TX LIKELY HAVE A TENTH OF AN INCH IF THAT. DESPITE CLOUD COVER STILL THINK MAX TEMPS IN THE UPPER 70S LOOK GOOD WITH MOISTURE AND WARM ADVECTION IN PLACE TODAY. COLD FRONT CURRENTLY WORKING THROUGH OKLA AND W TX WILL PUSH INTO SE TX TONIGHT AND OFF THE COAST BY 12Z TUE. THIS SHOULD END ANY RAIN CHANCES FOR SE TX WITH THE BULK OF THE PRECIP IN THE GULF HEADED TOWARDS N GULF COAST. COLD ADVECTION DURING THE DAY SHOULD KEEP MAX TEMPS IN THE MID 70S ALONG THE COAST AND LOW 70S FARTHER INLAND. HIGH PRESSURE WILL BUILD OVER SE TX FOR WED MORNING SO EXPECT MIN TEMPS BACK IN THE UPPER 40S TO LOW 50S. NEAR TO BELOW NORMAL TEMPERATURES ARE LIKELY TO CONTINUE THE REST OF THE WEEK. UPPER LEVEL PATTERN SHOULD BE QUITE AMPLIFIED WITH LONG WAVE TROUGH OVER THE GREAT LAKES AND NW FLOW ACROSS THE PLAINS DUE TO RIDGING OVER THE WEST COAST. SHORT WAVE TROUGH STILL EXPECTED TO IMPACT N TX THROUGH SE TX ON SATURDAY BUT LOOKS MUCH WEAKER. MOISTURE WILL ALSO BE LIMITED SO BACKED OFF ON POPS SOME BUT KEPT A PERIOD OF 20 POPS FOR NORTHERN AREAS OF SE TX WHERE LIFT MAY BE MAXIMIZED. OTHERWISE FORECAST SHOULD BE DRY THROUGH THE WEEKEND. TEMPERATURES WERE NOT ADJUSTED VERY MUCH BUT DID TREND TEMPS COOLER FOR THE WEEKEND. ANOTHER AREA OF HIGH PRESSURE WILL BUILD OVER THE MISS RIVER VALLEY WITH NE/E BOUNDARY LAYER FLOW OVER SE TX. THIS SHOULD ALLOW FOR COOLER AIR TO FILTER INTO THE REGION FOR THE WEEKEND. THIS WILL LIKELY KEEP TEMPS NEAR NORMAL OR EVEN A DEGREE OR TWO BELOW NORMAL. 39 MARINE... ONSHORE FLOW THIS MORNING WILL PERSIST THROUGH THE DAY AHEAD OF A COLD FRONT WHICH WILL PUSH OFFSHORE JUST BEFORE DAYBREAK ON TUESDAY. CAUTION FLAGS WILL BE NEEDED IN THE WAKE OF THE FRONT WITH ADVISORY CONDITIONS POSSIBLE FOR A BRIEF PERIOD ON TUESDAY. EXPECT BRISK NORTH AND NORTHEAST WINDS THROUGH THE END OF THE WEEK WITH CAUTION FLAGS POSSIBLE FOR MOST OF THE WEEK. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 78 54 73 51 77 / 30 20 10 10 10 HOUSTON (IAH) 79 58 75 52 78 / 50 20 10 10 10 GALVESTON (GLS) 79 67 77 62 77 / 50 40 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...39 AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
442 AM CDT MON OCT 21 2013 .DISCUSSION... BASED ON 00Z UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY...FIRST OF A COUPLE OF SHORT WAVE TROUGHS IS AFFECTING SE TX THIS MORNING. UPWARD VERTICAL MOTION FROM THE FIRST SHORTWAVE IS SUPPORTING CONVECTION BETWEEN VICTORIA AND WHARTON THIS MORNING ON RADAR IMAGERY. ALSO GETTING QUITE A BIT OF CONVECTION TO DEVELOP OFF THE LOWER TX COAST AND S TX. SECOND MORE SIGNIFICANT TROUGH AXIS IS BACK OVER THE S ROCKIES AND SHOULD BE PUSHING THROUGH LATER TODAY AND TONIGHT AS IT SHEARS OUT. JET STEAM IS ALSO EXPECTED TO BECOME MORE FAVORABLE FOR UPWARD MOTION AS IT STRENGTHENS OVER THE MID SOUTH AND POSITIONS DIVERGENCE OVER SE TX FROM RIGHT ENTRANCE REGION OF THE JET. EXPECT THERE TO BE SOME ISENTROPIC LIFT AS WELL FROM DISSIPATING FRONTAL BOUNDARY IN THE GULF. ALL OF THIS SHOULD SUPPORT SOME RAINFALL ACROSS THE SOUTHERN PORTION OF SE TX AND ALONG THE COAST. THE 06Z HRRR AND 00Z TX TECH WRF KEEP MOST OF THE PRECIP OFF THE COAST AND HAVE ORIENTED POPS AS SUCH. POPS MAY BE ABOUT 10 PERCENT TOO HIGH ACROSS THE BOARD FOR INLAND AREAS BUT THINK THAT MOST AREAS WILL SEE AT LEAST SOME RAIN...JUST LOWER AMOUNTS. LOOKS LIKE THE COASTAL COUNTIES WILL LIKELY HAVE MAYBE 0.25-0.5 INCHES OF RAIN. AN 1 INCH TOTALS WILL BE OUT IN THE GULF. THE REST OF SE TX LIKELY HAVE A TENTH OF AN INCH IF THAT. DESPITE CLOUD COVER STILL THINK MAX TEMPS IN THE UPPER 70S LOOK GOOD WITH MOISTURE AND WARM ADVECTION IN PLACE TODAY. COLD FRONT CURRENTLY WORKING THROUGH OKLA AND W TX WILL PUSH INTO SE TX TONIGHT AND OFF THE COAST BY 12Z TUE. THIS SHOULD END ANY RAIN CHANCES FOR SE TX WITH THE BULK OF THE PRECIP IN THE GULF HEADED TOWARDS N GULF COAST. COLD ADVECTION DURING THE DAY SHOULD KEEP MAX TEMPS IN THE MID 70S ALONG THE COAST AND LOW 70S FARTHER INLAND. HIGH PRESSURE WILL BUILD OVER SE TX FOR WED MORNING SO EXPECT MIN TEMPS BACK IN THE UPPER 40S TO LOW 50S. NEAR TO BELOW NORMAL TEMPERATURES ARE LIKELY TO CONTINUE THE REST OF THE WEEK. UPPER LEVEL PATTERN SHOULD BE QUITE AMPLIFIED WITH LONG WAVE TROUGH OVER THE GREAT LAKES AND NW FLOW ACROSS THE PLAINS DUE TO RIDGING OVER THE WEST COAST. SHORT WAVE TROUGH STILL EXPECTED TO IMPACT N TX THROUGH SE TX ON SATURDAY BUT LOOKS MUCH WEAKER. MOISTURE WILL ALSO BE LIMITED SO BACKED OFF ON POPS SOME BUT KEPT A PERIOD OF 20 POPS FOR NORTHERN AREAS OF SE TX WHERE LIFT MAY BE MAXIMIZED. OTHERWISE FORECAST SHOULD BE DRY THROUGH THE WEEKEND. TEMPERATURES WERE NOT ADJUSTED VERY MUCH BUT DID TREND TEMPS COOLER FOR THE WEEKEND. ANOTHER AREA OF HIGH PRESSURE WILL BUILD OVER THE MISS RIVER VALLEY WITH NE/E BOUNDARY LAYER FLOW OVER SE TX. THIS SHOULD ALLOW FOR COOLER AIR TO FILTER INTO THE REGION FOR THE WEEKEND. THIS WILL LIKELY KEEP TEMPS NEAR NORMAL OR EVEN A DEGREE OR TWO BELOW NORMAL. 39 && .MARINE... ONSHORE FLOW THIS MORNING WILL PERSIST THROUGH THE DAY AHEAD OF A COLD FRONT WHICH WILL PUSH OFFSHORE JUST BEFORE DAYBREAK ON TUESDAY. CAUTION FLAGS WILL BE NEEDED IN THE WAKE OF THE FRONT WITH ADVISORY CONDITIONS POSSIBLE FOR A BRIEF PERIOD ON TUESDAY. EXPECT BRISK NORTH AND NORTHEAST WINDS THROUGH THE END OF THE WEEK WITH CAUTION FLAGS POSSIBLE FOR MOST OF THE WEEK. 38 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 78 54 73 51 77 / 30 20 10 10 10 HOUSTON (IAH) 79 58 75 52 78 / 50 20 10 10 10 GALVESTON (GLS) 79 67 77 62 77 / 50 40 10 10 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ DISCUSSION...39 AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1224 PM CDT MON OCT 21 2013 .UPDATE... ISSUED AT 926 AM CDT MON OCT 21 2013 ADDED SCATTERED FLURRIES TO MUCH OF THE FORECAST AREA TODAY AS SUBTLE SHORTWAVE TROUGH ROUNDS THE BASE OF THE UPPER LEVEL LOW. DEPTH OF THE LOW LEVEL CLOUD DECK OFF THE 21.12Z MPX SOUNDING AND FORECAST RAP SOUNDINGS FOR THIS MORNING INTO THE AFTERNOON HOURS RANGES FROM 2 TO 6 KFT...IN CONJUNCTION WITH WEAK LIFT...AND LAPSE RATES WILL BE SUFFICIENTLY STEEP FOR WEAK CONVECTIVE INSTABILITY SNOW SHOWERS OR FLURRIES TO DEVELOP. UPSTREAM REPORTS FROM THE TWIN CITIES AREA OF SNOW FLURRIES MATCHES WITH THE WEAK RADAR RETURNS. SKIES WILL BE OVERCAST FOR MUCH OF THE DAY...AND TEMPERATURES WILL STRUGGLE TO RISE A LOT. LOWERED HIGHS A BIT TO ACCOUNT FOR THIS. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 259 AM CDT MON OCT 21 2013 THE SURFACE LOW THAT MOVED ACROSS THE REGION SUNDAY IS MOVING ACROSS NORTHERN LAKE MICHIGAN EARLY THIS MORNING. A TROUGH OF LOW PRESSURE EXTENDS NORTHWEST FROM THE LOW ACROSS LAKE SUPERIOR INTO SOUTHERN CANADA. THE SURFACE LOW IS EXPECTED TO KEEP MOVING NORTHEAST TOWARD HUDSON BAY TODAY AND AS IT DOES...THE TROUGH OF LOW PRESSURE SHOULD PIVOT AROUND THE BACK SIDE OF THE LOW AND EXTEND FROM THE LOW BACK TO THE SOUTHWEST ACROSS LAKE SUPERIOR. THIS IS FARTHER NORTH THAN EARLIER MODELS RUNS WERE INDICATED...BUT THIS NORTHWARD SHIFT IN POSITION OF THE TROUGH HAS BEEN A CONSISTENT TREND IN THE MODELS AS WELL. THIS WILL ALL OCCUR AS THE UPPER LEVEL LOW OVER THE SOUTHWEST CORNER OF ONTARIO STARTS TO TURN SOUTHEAST AND MOVE TOWARD THE U.P. OF MICHIGAN TODAY. THE FORCING WITH THE UPPER LEVEL LOW IS EXPECTED TO STAY WELL TO THE NORTHEAST OF THE AREA WITH ALL THE QG CONVERGENCE STAYING OVER LAKE SUPERIOR INTO ONTARIO. THE 21.00Z MODELS HAVE ALSO REMAINED CONSISTENT IN SHOWING THE DEEPEST MOISTURE STAYING ALONG AND NORTH OF THE SURFACE TROUGH WITH STRONG MID LEVEL DRYING WORKING IN UNDERNEATH THE UPPER LEVEL LOW. WITH THE SURFACE TROUGH FARTHER TO THE NORTH AND THE EXPECTED MID LEVEL DRYING...REMOVED THE MENTION OF ANY PRECIPITATION ACROSS THE AREA FOR TODAY. THE FOCUS THEN TURNS TO THE NEXT SHORT WAVE TROUGH TO COME DOWN IN THE NORTHWEST FLOW FOR LATE TONIGHT INTO TUESDAY. THE MODELS ARE ALL FAIRLY CONSISTENT IN SHOWING THIS WAVE PASSING BY TO THE SOUTHWEST OF THE AREA BUT CLOSE ENOUGH TO PRODUCE AS MUCH AS 8 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA LATE TONIGHT INTO TUESDAY MORNING. WEAK TO MODERATE QG CONVERGENCE SHOULD OCCUR IN THE 1000-300 MB LAYER WITH THIS WAVE MAINLY ACROSS NORTHEAST IOWA. WITH THE SURFACE LOW EXPECTED TO TRACK FROM SOUTHEAST SOUTH DAKOTA TO NORTHERN MISSOURI TONIGHT THROUGH TUESDAY MORNING...ALL THE ISENTROPIC UP GLIDE REMAINS CLOSE TO THE SURFACE LOW AND SOUTH OF THE AREA. ENOUGH FORCING FROM THIS SYSTEM TO JUSTIFY HAVING A CHANCE OF PRECIPITATION ACROSS THE SOUTH FOR LATE TONIGHT THROUGH TUESDAY MORNING. SOUNDINGS SUGGEST PLENTY OF ICE WILL BE AVAILABLE IN THE CLOUDS AND EXPECT ANY PRECIPITATION TYPE ISSUES TO BE CONTROLLED BY LOW LEVEL TEMPERATURES. SO EXPECT THIS TO MAINLY BE SNOW POSSIBLY MIXING WITH SOME RAIN TOWARD THE END OF THE EVENT TUESDAY MORNING. COULD BE A VERY SIMILAR SYSTEM COMING THROUGH THE NORTHWEST FLOW FOR WEDNESDAY. THE 21.00Z GFS AND ECMWF BOTH SHOW THE SURFACE LOW DROPPING SOUTHEAST THROUGH THE MISSOURI RIVER VALLEY AND BRUSHING THE SOUTHWEST SECTIONS OF THE FORECAST AREA WITH SOME PRECIPITATION WHILE THE 21.00Z NAM BARELY SHOWS ANYTHING. BASED ON THE AGREEMENT BETWEEN THE GFS AND ECMWF...ADDED IN A SMALL CHANCE OF SOME PRECIPITATION ACROSS THE SOUTHWEST PARTS OF THE AREA. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 259 AM CDT MON OCT 21 2013 THE NORTHWEST FLOW ALOFT IS EXPECTED TO CONTINUE UNTIL POSSIBLY VERY LATE IN THE PERIOD WHEN THERE IS SOME SUGGESTION OF THE WESTERN RIDGE BREAKING DOWN ALLOWING THE FLOW OVER THE UPPER MIDWEST TO BECOME ZONAL. MODELS ALSO CONTINUE TO SHOW A SYSTEM COMING ACROSS THE GREAT LAKES REGION IN THE NORTHWEST FLOW IN THE FRIDAY NIGHT INTO SATURDAY TIME FRAME. HOWEVER...STILL SOME DIFFERENCES ON THE TRACK OF THE SYSTEM WITH THE GFS BRINGING THE SURFACE LOW ACROSS WISCONSIN AND SHOWING PRECIPITATION OVER THE AREA WHILE THE 22.00Z ECMWF TAKES THE SURFACE ACROSS ONTARIO KEEPING THE AREA DRY. THE 22.00Z GEM LOOKS TO BE MUCH WEAKER WITH NO SURFACE LOW BUT DOES PRODUCE SOME PRECIPITATION ACROSS NORTHEAST WISCONSIN. FOR NOW...WILL STAY WITH THE MODEL CONSENSUS GRIDS AND SHOW SOME SMALL PRECIPITATION CHANCES FOR FRIDAY NIGHT AND SATURDAY. BELOW TEMPERATURES TO CONTINUE THROUGH THE PERIOD...BUT SOME WARMING POSSIBLE FOR NEXT WEEKEND...POSSIBLY APPROACHING 50 ACROSS THE FAR SOUTH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1131 AM CDT MON OCT 21 2013 ANY HOLES IN THE CLOUD DECK THIS MORNING WILL BECOME BROKEN TO OVERCAST AS AFTERNOON CUMULUS TAKE OVER. BASES WILL BE VFR...MAINLY IN THE 4 TO 6 KFT RANGE AND GUSTY NORTHWEST WINDS TO PERSIST THROUGH EARLY EVENING. CLOUD TRENDS OVERNIGHT ARE LESS CONFIDENT AS CURRENT SYSTEM PULLS AWAY...AND AHEAD OF THE NEXT SHORTWAVE TROUGH THAT WILL DROP SOUTHEAST INTO THE AREA. THERE COULD BE A PERIOD OF CLEAR TO MOSTLY CLEAR SKIES OVERNIGHT BUT SHOULD QUICKLY FILL IN WITH MID TO HIGH LEVEL CLOUDS FROM THE NORTHWEST. THE CURRENT FORECAST IS ON THE PESSIMISTIC SIDE...KEEPING A BROKEN DECK THROUGH THE PERIOD. BY LATER TUESDAY MORNING...A LOWER BUT STILL VFR DECK COULD DEVELOP. THE RESTRICTIVE CEILINGS AND CHANCES OF PRECIPITATION TUESDAY MORNING WILL BE OFF TO THE SOUTH...ACROSS CENTRAL AND EASTERN IOWA. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE.......ZT SHORT TERM...04 LONG TERM....04 AVIATION.....ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
926 AM CDT MON OCT 21 2013 .UPDATE...TODAY ISSUED AT 926 AM CDT MON OCT 21 2013 ADDED SCATTERED FLURRIES TO MUCH OF THE FORECAST AREA TODAY AS SUBTLE SHORTWAVE TROUGH ROUNDS THE BASE OF THE UPPER LEVEL LOW. DEPTH OF THE LOW LEVEL CLOUD DECK OFF THE 21.12Z MPX SOUNDING AND FORECAST RAP SOUNDINGS FOR THIS MORNING INTO THE AFTERNOON HOURS RANGES FROM 2 TO 6 KFT...IN CONJUNCTION WITH WEAK LIFT...AND LAPSE RATES WILL BE SUFFICIENTLY STEEP FOR WEAK CONVECTIVE INSTABILITY SNOW SHOWERS OR FLURRIES TO DEVELOP. UPSTREAM REPORTS FROM THE TWIN CITIES AREA OF SNOW FLURRIES MATCHES WITH THE WEAK RADAR RETURNS. SKIES WILL BE OVERCAST FOR MUCH OF THE DAY...AND TEMPERATURES WILL STRUGGLE TO RISE A LOT. LOWERED HIGHS A BIT TO ACCOUNT FOR THIS. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 259 AM CDT MON OCT 21 2013 THE SURFACE LOW THAT MOVED ACROSS THE REGION SUNDAY IS MOVING ACROSS NORTHERN LAKE MICHIGAN EARLY THIS MORNING. A TROUGH OF LOW PRESSURE EXTENDS NORTHWEST FROM THE LOW ACROSS LAKE SUPERIOR INTO SOUTHERN CANADA. THE SURFACE LOW IS EXPECTED TO KEEP MOVING NORTHEAST TOWARD HUDSON BAY TODAY AND AS IT DOES...THE TROUGH OF LOW PRESSURE SHOULD PIVOT AROUND THE BACK SIDE OF THE LOW AND EXTEND FROM THE LOW BACK TO THE SOUTHWEST ACROSS LAKE SUPERIOR. THIS IS FARTHER NORTH THAN EARLIER MODELS RUNS WERE INDICATED...BUT THIS NORTHWARD SHIFT IN POSITION OF THE TROUGH HAS BEEN A CONSISTENT TREND IN THE MODELS AS WELL. THIS WILL ALL OCCUR AS THE UPPER LEVEL LOW OVER THE SOUTHWEST CORNER OF ONTARIO STARTS TO TURN SOUTHEAST AND MOVE TOWARD THE U.P. OF MICHIGAN TODAY. THE FORCING WITH THE UPPER LEVEL LOW IS EXPECTED TO STAY WELL TO THE NORTHEAST OF THE AREA WITH ALL THE QG CONVERGENCE STAYING OVER LAKE SUPERIOR INTO ONTARIO. THE 21.00Z MODELS HAVE ALSO REMAINED CONSISTENT IN SHOWING THE DEEPEST MOISTURE STAYING ALONG AND NORTH OF THE SURFACE TROUGH WITH STRONG MID LEVEL DRYING WORKING IN UNDERNEATH THE UPPER LEVEL LOW. WITH THE SURFACE TROUGH FARTHER TO THE NORTH AND THE EXPECTED MID LEVEL DRYING...REMOVED THE MENTION OF ANY PRECIPITATION ACROSS THE AREA FOR TODAY. THE FOCUS THEN TURNS TO THE NEXT SHORT WAVE TROUGH TO COME DOWN IN THE NORTHWEST FLOW FOR LATE TONIGHT INTO TUESDAY. THE MODELS ARE ALL FAIRLY CONSISTENT IN SHOWING THIS WAVE PASSING BY TO THE SOUTHWEST OF THE AREA BUT CLOSE ENOUGH TO PRODUCE AS MUCH AS 8 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER ACROSS THE SOUTHERN PARTS OF THE FORECAST AREA LATE TONIGHT INTO TUESDAY MORNING. WEAK TO MODERATE QG CONVERGENCE SHOULD OCCUR IN THE 1000-300 MB LAYER WITH THIS WAVE MAINLY ACROSS NORTHEAST IOWA. WITH THE SURFACE LOW EXPECTED TO TRACK FROM SOUTHEAST SOUTH DAKOTA TO NORTHERN MISSOURI TONIGHT THROUGH TUESDAY MORNING...ALL THE ISENTROPIC UP GLIDE REMAINS CLOSE TO THE SURFACE LOW AND SOUTH OF THE AREA. ENOUGH FORCING FROM THIS SYSTEM TO JUSTIFY HAVING A CHANCE OF PRECIPITATION ACROSS THE SOUTH FOR LATE TONIGHT THROUGH TUESDAY MORNING. SOUNDINGS SUGGEST PLENTY OF ICE WILL BE AVAILABLE IN THE CLOUDS AND EXPECT ANY PRECIPITATION TYPE ISSUES TO BE CONTROLLED BY LOW LEVEL TEMPERATURES. SO EXPECT THIS TO MAINLY BE SNOW POSSIBLY MIXING WITH SOME RAIN TOWARD THE END OF THE EVENT TUESDAY MORNING. COULD BE A VERY SIMILAR SYSTEM COMING THROUGH THE NORTHWEST FLOW FOR WEDNESDAY. THE 21.00Z GFS AND ECMWF BOTH SHOW THE SURFACE LOW DROPPING SOUTHEAST THROUGH THE MISSOURI RIVER VALLEY AND BRUSHING THE SOUTHWEST SECTIONS OF THE FORECAST AREA WITH SOME PRECIPITATION WHILE THE 21.00Z NAM BARELY SHOWS ANYTHING. BASED ON THE AGREEMENT BETWEEN THE GFS AND ECMWF...ADDED IN A SMALL CHANCE OF SOME PRECIPITATION ACROSS THE SOUTHWEST PARTS OF THE AREA. .LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY) ISSUED AT 259 AM CDT MON OCT 21 2013 THE NORTHWEST FLOW ALOFT IS EXPECTED TO CONTINUE UNTIL POSSIBLY VERY LATE IN THE PERIOD WHEN THERE IS SOME SUGGESTION OF THE WESTERN RIDGE BREAKING DOWN ALLOWING THE FLOW OVER THE UPPER MIDWEST TO BECOME ZONAL. MODELS ALSO CONTINUE TO SHOW A SYSTEM COMING ACROSS THE GREAT LAKES REGION IN THE NORTHWEST FLOW IN THE FRIDAY NIGHT INTO SATURDAY TIME FRAME. HOWEVER...STILL SOME DIFFERENCES ON THE TRACK OF THE SYSTEM WITH THE GFS BRINGING THE SURFACE LOW ACROSS WISCONSIN AND SHOWING PRECIPITATION OVER THE AREA WHILE THE 22.00Z ECMWF TAKES THE SURFACE ACROSS ONTARIO KEEPING THE AREA DRY. THE 22.00Z GEM LOOKS TO BE MUCH WEAKER WITH NO SURFACE LOW BUT DOES PRODUCE SOME PRECIPITATION ACROSS NORTHEAST WISCONSIN. FOR NOW...WILL STAY WITH THE MODEL CONSENSUS GRIDS AND SHOW SOME SMALL PRECIPITATION CHANCES FOR FRIDAY NIGHT AND SATURDAY. BELOW TEMPERATURES TO CONTINUE THROUGH THE PERIOD...BUT SOME WARMING POSSIBLE FOR NEXT WEEKEND...POSSIBLY APPROACHING 50 ACROSS THE FAR SOUTH. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 650 AM CDT MON OCT 21 2013 A WEAK TROUGH WILL GENERATE ISOLATED SHOWERS ACROSS WESTERN WISCONSIN THROUGH 21.15Z. SINCE THE MESO MODELS SUGGEST THAT THESE SHOWERS WILL BE EAST OF KLSE...IT WAS NOT INCLUDED IN THE TAF. OVERALL THE MAIN CONCERN IN THE FORECAST WILL BE THE CLOUDS. SOME MVFR CLOUDS WILL CONTINUE TO BE SEEN IN KLSE THROUGH 21.14Z AND THEN THE CEILINGS WILL REMAIN IN THE 4 TO 6K RANGE INTO THIS EVENING. THE MODELS HINT THAT THESE CLOUDS WILL BECOME SCATTERED BECOME 21.21Z AND 22.03Z. HOWEVER WITH MODELS NOT DOING THE GREATEST ON THIS CLEARING ACROSS MANITOBA AT THE MOMENT...DECIDED TO DELAY THIS CLEARING UNTIL AFTER 22.06Z. THIS IS CORRESPONDING TO THE INVERSION RISING AHEAD OF THE NEXT SHORT WAVE TROUGH. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...ZT SHORT TERM...04 LONG TERM...04 AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
220 AM EDT WED OCT 23 2013 .SYNOPSIS... A COLD FRONT WILL PASS FARTHER TO THE SOUTH AND EAST OF THE AREA OVERNIGHT. LOW PRESSURE WILL START TO DEVELOP OFF THE MID ATLANTIC COAST ON WEDNESDAY...AND THEN PASS TO THE EAST WHILE INTENSIFYING WEDNESDAY NIGHT. A WEAK LOW PRESSURE TROUGH WILL MOVE ACROSS THE AREA ON THURSDAY. HIGH PRESSURE WILL THEN BUILD TO THE SOUTH ON FRIDAY...AND SLIDE EAST ON ON SATURDAY. A FRONTAL SYSTEM WILL MOVE THROUGH ON SUNDAY...FOLLOWED BY HIGH PRESSURE EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... MINOR ADJUSTMENTS TO TEMPS AND DEWPOINTS AS WELL AS CLOUD COVERAGE. THERE IS A GOOD CONSENSUS AMONGST MODEL GUIDANCE THAT THE FORECAST AREA STAYS DRY THROUGH TONIGHT. HRRR HAS CONTINUED TO TREND SLOWER WITH THE ONSET OF LIGHT RAIN...HOLDING OFF UNTIL WEDNESDAY MORNING WITH ANY LIGHT RAIN. REMOVED POPS FOR TONIGHT. STILL KEEPING PATCHY FROST FOR THE OVERNIGHT PERIOD FOR INTERIOR AREAS. MIN TEMPS WILL LIKELY BE ACHIEVED AROUND MIDNIGHT TO AN HOUR OR TWO PROCEEDING MIDNIGHT. THEN TEMPS WILL SLOWLY DECREASE OR BECOME NEARLY STEADY AS A THICKENING MID-HIGH LEVEL CLOUD DECK BEGINS TO MOVE IN FROM WEST TO EAST...AND CAUSES RERADIATION OF LONGWAVE IR. A COLD FRONT WILL PUSH FARTHER SOUTH AND EAST OF THE AREA OVERNIGHT WITH MORE MID TO HIGH CLOUDS MOVING IN FROM THE WEST. THIS WILL BE VIA MID LEVEL ISENTROPIC LIFT AND DCVA FROM A WEAK MID LEVEL SHORTWAVE AHEAD OF AN APPROACHING UPPER TROUGH. THE CLOUDS PLUS STRONGER WINDS JUST OFF THE SFC SHOULD BE ENOUGH TO PREVENT FROST FROM BECOMING WIDESPREAD. EXPECT LOWS FROM 35-40 INLAND AND NEAR PINE BARRENS OF LI...TO THE LOWER AND MID 40S MOST ELSEWHERE...TO THE UPPER 40S INVOF NYC. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/... AFOREMENTIONED COOL AIR MASS WILL INTERACT WITH THE GULF STREAM TO ENHANCE A LOW LEVEL BAROCLINIC ZONE NORTH OF THE GULF STREAM. A POTENT MID LEVEL SHORTWAVE WILL INTERACT WITH THIS ZONE TO SPAWN A WEAK SFC LOW OFF THE MID ATLANTIC COAST WED MORNING... WHICH SHOULD THEN MOVE TO THE NE. SIDED MORE WITH A GFS/NAM VS ECMWF SOLUTION FOR THE EVOLUTION OF THIS SYSTEM. STRONG MID LEVEL DCVA VIA A STRONG VORT MAX ROUNDING THE BASE OF THE APPROACHING UPPER TROUGH...PLUS DEVELOPING H7-8 FRONTOGENETIC FORCING AND NEGATIVE SATURATED H7-5 EPV...SHOULD LEAD TO PDS OF MODERATE RAIN OUT EAST. EXACT PLACEMENT OF BANDS OF HEAVIER RAIN STILL SOMEWHAT IN QUESTION GIVEN THE MESOSCALE FORCING INVOLVED...THEIR MOST LIKELY LOCATION ATTM APPEARS TO BE ACROSS CENTRAL/EASTERN LONG ISLAND AND SE CT. MEANWHILE MUCH OF THE LOWER HUDSON VALLEY AND INTERIOR NE NJ MAY SEE VERY LITTLE IN THE WAY OF PRECIP..BUT IF PRECIP DOES DEVELOP THERE EARLY ENOUGH IN THE MORNING A FEW SLEET PELLETS NOT OUT OF THE QUESTION WITH SOME LOW LEVEL DRY AIR TO BE OVERCOME AND WET-BULB TEMPS IN MOST OF THE VERTICAL COLUMN AOB FREEZING. A NE-N BREEZE PLUS CLOUD COVER AND PRECIP WILL LEAD TO A RATHER COOL DAY...WITH HIGHS ONLY IN THE UPPER 40S IN THE HIGHER ELEVATIONS AND LOWER 50S ELSEWHERE. AS THE LOW HEADS OFF TO THE EAST WED NIGHT...EXPECT DECENT CAA TO LEAD TO LOWS IN THE 30S AND LOWER 40S. IF CAA IS STRONG ENOUGH PER COLDER MAV GUIDANCE...INTERIOR SECTIONS COULD SEE LOWS AOB FREEZING. NOT ENOUGH CONFIDENCE TO ISSUE A FREEZE WATCH YET...BUT THIS COULD CHANGE WITH LATER FORECASTS SO HAVE MENTIONED IN HWO. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A BROAD TROUGH OVER THE EASTERN HALF OF NOAM WILL REMAIN THROUGH THE END OF THE WEEK. THE TROF AXIS IS FORECAST TO PASS THROUGH ON FRI WITH RISING HEIGHTS THEREAFTER. ZONAL FLOW RETURNS BRIEFLY ON SAT...BUT ANOTHER TROUGH WILL MOVE THROUGH ON SUN. NEARLY ZONAL FLOW THEN RETURNS FOR EARLY NEXT WEEK. AT THE SFC...A WEAK TROF WILL MOVE ACROSS THE AREA ON THU. A W TO NW FLOW WILL PREVAIL BEHIND IT...WITH THE LAKE EFFECT MACHINE TURNING ON THU AND FRI. CURRENTLY...IT LOOKS AS IF ALL PRECIP WILL REMAIN N AND W OF THE FORECAST AREA...BUT DO EXPECT AN INCREASE IN CLOUD COVER ACROSS NW ZONES. COOLER AIR MOVING OVER THE WARMER OCEAN MAY ALSO CAUSE OCEAN EFFECT SHOWERS OVER THE WATERS. HIGH PRES BUILDING TO THE S FRI AND SAT WILL RESULT IN DRY CONDS. THE BEST CHC FOR ANY PRECIP WILL BE WITH A FRONTAL SYSTEM MOVING THROUGH ON SUN. MODELS KEEP THE BULK OF THE PRECIP N OF THE AREA WHERE THE BETTER DYNAMICS WILL BE AND SINCE THE TREND OVER THE LAST SEVERAL MONTHS HAS BEEN DRIER...KEPT THE SCHC POPS THAT WERE PREVIOUSLY FORECAST. CANADIAN HIGH PRES THEN BUILDS TOWARDS THE AREA EARLY NEXT WEEK. TEMPS WILL GENERALLY BE 5 TO 10 DEGREES BELOW NORMAL LEVELS THROUGH THE PERIOD. THERE IS THE POSSIBILITY OF FREEZING LOWS FOR PORTIONS OF INTERIOR ZONES ON THU NIGHT AND MUCH OF THE INTERIOR FRI NIGHT. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... LOW PRESSURE PASSES TO THE SOUTH TODAY. WINDS 10KT OR LESS TURN TO THE NE THIS MORNING...THEN BACK TOWARDS N IN THE AFTERNOON...THEN FINALLY NW LATE AFTERNOON/EARLY EVENING. TIMING COULD BE OFF BY AN HOUR OR TWO WITH THE WIND SHIFTS. CIGS LOWERING TO MOSTLY 3500-5000 FT THIS AFTN INTO EARLY EVENING. TEMPO GROUPS WITH CIGS 2500-3000 FT MIGHT NOT OCCUR. DRY WEATHER ALSO POSSIBLE FOR ALL TERMINALS EXCEPT KJFK/KISP/KGON. GUSTS AFTER THE EVENING PUSH MIGHT ONLY BE OCCASIONAL. OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... .WEDNESDAY NIGHT...VFR WITH CLEARING SKIES. OCNL GUSTS 20KT. .THURSDAY...VFR. W GUSTS AROUND 25KT. .THURSDAY NIGHT-SATURDAY...VFR. W GUSTS 20-25KT THURS EVENING. .SATURDAY NIGHT-SUNDAY...VFR. CHC MVFR/-SHRA WITH A COLD FRONT. && .MARINE... WIND GUSTS AFTER COLD FROPA ON THE OCEAN COULD NEAR 25 KT TONIGHT. ALSO...N-NW FLOW ON THE BACK SIDE OF DEPARTING LOW PRESSURE COULD GUST CLOSE TO 25 KT LATE DAY WED...WITH OCEAN SEAS POSSIBLY NEARING 5 FT ATTM. NO SCA ISSUED ATTM. A MODERATE WESTERLY FLOW MAY CAUSE MARGINAL SCA CONDS ON THE EASTERN OCEAN WATERS THU/THU NIGHT. SUB-ADVY CONDS ARE THEN EXPECTED THROUGH SAT WITH HIGH PRES BUILDING S OF THE WATERS. AN INCREASING SW FLOW AHEAD OF A COLD FRONT SAT NIGHT COULD CAUSE SCA CONDS TO RETURN...PRIMARILY FOR SEAS ON THE OCEAN WATERS. && .HYDROLOGY... THERE COULD BE SOME ISOLD 1/2 INCH RAINFALL TOTALS ON LONG ISLAND ON WED. OTHERWISE...MOST OF NYC LONG ISLAND AND SOUTHERN CT SHOULD SEE 1/4 TO 1/2 INCH OF RAIN...WITH LESS AMTS NORTH/WEST. NO SIGNIFICANT PRECIP EXPECTED THEREAFTER. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...GOODMAN/24 NEAR TERM...GOODMAN/JM SHORT TERM...GOODMAN LONG TERM...GOODMAN/24 AVIATION...JC MARINE...GOODMAN/24 HYDROLOGY...GOODMAN
AREA FORECAST DISCUSSION
NWS MIAMI FL
131 AM EDT WED OCT 23 2013 .AVIATION... A FEW SHOWERS CONTINUE ACROSS DEEP SOUTH FLORIDA...WITH A LINE OF SHOWERS ACROSS THE ATLANTIC WATERS EARLY THIS MORNING. A COUPLE SHOWERS COULD GET NEAR THE TAF SITES OVERNIGHT...BUT LEFT OUT FOR NOW. LIGHT WINDS TO A LIGHT WEST TO SOUTHWEST FLOW WILL CONTINUE OVERNIGHT. A COLD FRONT IS FORECAST TO MOVE SOUTH ACROSS THE FLORIDA PENINSULA TODAY...WITH SCATTERED TO NUMEROUS SHOWERS AND SOME THUNDERSTORMS ACROSS THE REGION THIS AFTERNOON. SHOWERS MAY BEGIN SHORTLY AFTER DAYBREAK AT KAPF...WITH ACTIVITY BECOMING MORE NUMEROUS IN THE AFTERNOON FOR THE EAST COAST. ADDED VCTS FOR THE EAST COAST TAF SITES...AND LEFT KAPF WITH VCSH. WINDS WILL INCREASE OUT OF THE WEST AND NORTHWEST DURING THE DAY...WITH A WEAK EAST COAST SEA BREEZE STAYING NEAR THE COAST THIS AFTERNOON. A FEW OF THE TAF SITES COULD SWITCH TO NORTH NORTHEAST AROUND 21Z...WITH THE MOST LIKELY BEING KFLL. THE FRONTAL BOUNDARY IS FORECAST TO SLOWLY PUSH THROUGH THIS EVENING...WITH IMPROVING CONDITIONS. BRIEF MVFR/IFR CONDITIONS ARE POSSIBLE IN SHOWERS AND/OR THUNDERSTORMS. && .PREV DISCUSSION... /ISSUED 804 PM EDT TUE OCT 22 2013/ UPDATE... A COLD FRONT EXTENDING FROM SOUTHERN GEORGIA SOUTHWEST INTO THE EASTERN GULF OF MEXICO WILL CONTINUE TO MOVE SOUTHEAST DOWN THE SUNSHINE STATE TONIGHT AND THROUGH SOUTH FLORIDA ON WEDNESDAY. A PRE-FRONTAL TROUGH OF LOW PRESSURE WAS ALSO LOCATED OVER THE SOUTHEASTERN GULF OF MEXICO WHICH WILL MOVE EAST AND THROUGH SOUTH FLORIDA. THESE TWO SYSTEMS WILL KEEP A SOUTHWEST STEERING FLOW OVER SOUTH FLORIDA TONIGHT ALLOWING FOR TROPICAL MOISTURE TO WORK INTO THE AREA FROM THE GULF OF MEXICO. SO THE SHOWERS AND THUNDERSTORMS OVER THE EASTERN GULF OF MEXICO WILL CONTINUE TO WORK EAST AND INTO THE WESTERN AREAS OF SOUTH FLORIDA TONIGHT. THEREFORE...THE POPS WILL BE RAISED TO CHANCE CAT FOR THE WESTERN AREAS TONIGHT ALONG WITH ADDING THUNDER WORDING TO THE FORECAST. SHOWERS AND THUNDERSTORMS HAVE ALSO DEVELOPED OVER WESTERN CUBA EARLY THIS EVENING. THESE SHOWERS AND THUNDERSTORMS SHOULD MOVE NORTH NORTHEAST INTO THE FLORIDA KEYS AND POSSIBLY INTO THE SOUTHEASTERN AREAS OF SOUTH FLORIDA LATE TONIGHT INTO EARLY WEDNESDAY MORNING INCLUDING THE ADJACENT COASTAL WATERS. SO HAVE RAISED THE POPS UP OVER THE SOUTHEASTERN AREAS OF SOUTH FLORIDA TO LOW END CHANCE TONIGHT ALONG WITH ADDING THUNDER WORDING TO THE FORECAST. REST OF SOUTH FLORIDA SHOULD SEE ISOLATED SHOWERS TONIGHT. SO WILL KEEP A SLIGHT CHANCE OF POPS IN FOR THESE AREAS FOR TONIGHT. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES ARE PLANNED. UDPATED...54/BNB PREV DISCUSSION... /ISSUED 716 PM EDT TUE OCT 22 2013/ AVIATION...VFR WILL PREVAIL. HOWEVER, A FEW SHRA ARE POSSIBLE NEAR KAPF TONIGHT, ESPECIALLY LATE, ASSOCIATED WITH ACTIVITY DEVELOPING AHEAD OF THE COLD FRONT. THIS ACTIVITY IS EXPECTED TO SPREAD SE ON WED AHEAD OF THE FRONT, WITH SCATTERED SHRA AND ISOLATED TSRA POSSIBLE. FOR NOW, KEPT VCSH AT ALL TERMINALS AND WILL MONITOR FOR POSSIBLE TSRA DEVELOPMENT AND UPDATE AS NEEDED. WINDS WILL PREVAIL LIGHT OUT OF THE SW OVERNIGHT BECOMING W-NW 5-10 KT ON WED. /GREGORIA PREV DISCUSSION... /ISSUED 246 PM EDT TUE OCT 22 2013/ SHORT TERM (TONIGHT-THURSDAY NIGHT)... THE LATEST WRF/HRRR MODEL SOLUTIONS INDICATE MAINLY SCATTERED SEA BREEZE DRIVEN SHOWERS/TSTMS CONTINUING TO INITIATE ACROSS PORTIONS OF THE AREA...THEN BECOMING CONCENTRATED OVER THE NORTHEASTERN SECTIONS OF THE AREA OR AROUND THE LAKE REGION TO THE PALM BEACH COAST THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS BEFORE DIMINISHING. THE LATEST SHORT-RANGE MODEL GUIDANCE HAS INITIALIZED WELL WITH THE CURRENT SYNOPTIC PATTERN AND GENERALLY INDICATES THE ABOVE AVERAGE TEMPERATURES PERSISTING THROUGH WEDNESDAY AS A COLD FRONT APPROACHES AND MOVES INTO THE LOCAL AREA. OVERNIGHT LOWS ARE FORECAST TO DROP INTO THE 70S TONIGHT AND RETURN TO THE MID TO UPPER 80S THROUGH THE AFTERNOON PERIOD WEDNESDAY...WHICH IS AROUND 3-5 DEGREES WARMER THAN AVERAGE FOR THIS PERIOD. MODEL SOUNDINGS AROUND THE LOCAL AREA INDICATE THE DEEP SOUTHWEST FLOW ALONG WITH INCREASING DEEP LAYER MOISTURE CONTINUING AHEAD OF THE SHORTWAVE TROUGH CURRENTLY MOVING OVER THE MS VALLEY REGION. UPPER HEIGHTS WILL BEGIN TO FALL LATER TONIGHT THROUGH THE END OF THE PERIOD AS THIS UPPER TROUGH APPROACHES AND MOVES OVER THE EAST COAST. THE FRONTAL BOUNDARY IS FORECAST TO PUSH THROUGH THE LOCAL AREA THROUGH THE DAY WEDNESDAY WITH THE LOW-LEVEL WINDS FORECAST TO QUICKLY VEER AND INCREASE OUT OF THE NORTHEAST WEDNESDAY NIGHT THROUGH THURSDAY NIGHT. NORTHEAST WINDS WILL LIKELY BECOME GUSTY THROUGH THIS TIME THURSDAY...ESPECIALLY OVER THE ADJACENT MARINE AREAS AND ALONG THE EAST COAST. ALTHOUGH MUCH DRIER AND COOLER AIR WILL BEGIN TO SPREAD SOUTH INTO PORTIONS OF THE AREA THROUGH THE DAY THURSDAY...THE RAIN CHANCES WILL REMAIN UP OVER THE SOUTHERN HALF OF THE LOCAL AREA WHERE MODEL PWATS REMAIN AROUND THE 2" MARK. IN ADDITION TO THE RAIN CHANCES THURSDAY...SOME TSTMS WILL REMAIN POSSIBLE THROUGH THE FIRST HALF OF THE DAY OVER THESE SOUTHERN AREAS. LONG TERM (FRIDAY-MONDAY)... MODELS REMAIN IN AGREEMENT WITH A SECONDARY FRONT SURGING THROUGH THE AREA FRIDAY BRINGING A MUCH DRIER AIR MASS INTO SOUTH FLORIDA ALONG WITH BELOW NORMAL TEMPERATURES. FAIRLY WIDESPREAD 50S SHOULD BE SEEN ACROSS INTERIOR AREAS BOTH SATURDAY AND SUNDAY MORNINGS WITH HIGHS EACH DAY IN THE LOW 80S ACROSS THE EAST COAST. LONG-RANGE MODELS INDICATE THAT THE DRY PATTERN WILL CONTINUE ACROSS THE AREA INTO THE FIRST PART OF NEXT WEEK WITH NORTHEAST SURFACE FLOW PREVAILING. AVIATION...18Z TAFS OCT. 13 2013 CURRENTLY HAVE A FEW SHRA MOVING NNE ALONG THE EAST COAST SEA BREEZE AND THIS TREND WILL LIKELY TO CONTINUE THROUGH THE AFTERNOON WITH ADDITIONAL DEVELOPMENT OVER INLAND AREAS. THERE COULD ALSO BE A TSRA OR TWO BUT OVERALL CONFIDENCE AND COVERAGE TOO LOW TO PLACE IN THE FORECAST AT THIS TIME. SOME OF THE ACTIVITY COULD PERSIST INTO THE EVENING, HOWEVER THE HRRR HINTS AT LITTLE ACTIVITY PAST 00Z. SOME LOCATIONS COULD HAVE VERY BRIEF MVFR OR EVEN IFR BUT TIMING AND EXACT LOCATION WITH LOW COVERAGE ALWAYS DIFFICULT TO FORECAST SO LEFT LIMITED RESTRICTIONS FOR NOW AND WILL AMEND IF NECESSARY. MOST OF THE CONVECTION WILL BE WELL EAST OF KAPF UNTIL LATER IN THE FORECAST WHEN THE FRONT SHIFTS SOUTH AND MAY HAVE AN INCREASE IN SHRA OVER THE GULF WATERS AFT 06Z. KOB MARINE... LIGHT SOUTH-SOUTHEAST WINDS WILL SHIFT TO THE SOUTH- SOUTHWEST LATER TONIGHT AHEAD OF AN APPROACHING COLD FRONT. SCATTERED SHOWERS DEVELOPING OUT AHEAD OF THIS BOUNDARY WILL REMAIN POSSIBLE THROUGH THE MID-WEEK TIME FRAME. DRIER AIR ALONG WITH INCREASING WINDS AND SEAS ARE FORECAST TO SPREAD SOUTH OVER THE MARINE AREAS IN THE WAKE OF THE FRONT BEGINNING THURSDAY AND CONTINUING INTO THE UPCOMING WEEKEND. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 86 70 81 71 / 60 40 20 20 FORT LAUDERDALE 87 73 82 74 / 60 40 30 30 MIAMI 88 72 82 72 / 60 40 40 30 NAPLES 87 66 84 65 / 50 30 20 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...23/SK AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
454 AM CDT WED OCT 23 2013 .DISCUSSION... 327 AM CDT AFTER LOOKING LIKE EARLY WINTER YESTERDAY IT WILL CONTINUE TO FEEL AS SUCH FOR A COUPLE DAYS...WITH THE FORECAST CHALLENGES TIED TO WELL BELOW NORMAL TEMPERATURES THESE NEXT FEW DAYS AND THEN SWINGING BACK TO CLOSER TO NORMAL THIS WEEKEND AND MAYBE MORE SO INTO EARLY NEXT WEEK. SYNOPSIS...THE PESKY CLIPPER SYSTEM FROM YESTERDAY IS RACING EASTWARD ACROSS THE UPPER OHIO VALLEY EARLY THIS MORNING. IN ITS WAKE 70M HEIGHT FALLS WERE OBSERVED AT 500MB LAST EVE AS THE LARGE SCALE LONG WAVE TROUGH ACROSS EASTERN/CENTRAL NORTH AMERICA CONTINUES TO BE RE-ESTABLISHED. THAT WILL REMAIN THE DOMINANT INFLUENCE ON THE LOCAL WEATHER PATTERN THIS WEEK...WITH PERSISTENT UPPER LEVEL NORTHWEST FLOW. A SERIES OF MID-LEVEL PERTURBATIONS WILL TRAVERSE IN THIS FLOW TODAY AND TONIGHT...AGAIN FURTHER LEADING TO LOWERED HEIGHTS AND COLD ADVECTION. WITH HIGH PRESSURE REMAINING ACROSS THE CENTRAL PLAINS ALLOWING FOR NO RETURN LOW-LEVEL FLOW...THIS ENABLES AN IDEAL REGIME FOR TEMPERATURES TO REMAIN COLD BY MID-AUTUMN STANDARDS. EARLY THIS MORNING...LOW-LEVEL CONVERGENCE OVER THE LAKE HAS BEEN NOTED IN OBSERVATIONS AND EARLIER WAS ANALYZED FROM MID-LAKE INTO PORTER COUNTY. BUT THIS HAS SHIFTED EAST AND MOST OF THE DEVELOPMENT IS MOVING SOUTHEAST FROM IT...SO ALL IN ALL MOST IF NOT ALL OF PORTER COUNTY LOOKS TO REMAIN FREE OF THE CONVECTIVE SHOWERS OVER THE LAKE THIS MORNING. TODAY AND TONIGHT...MULTIPLE COMPACT AND SHEARED SHORT WAVES ARE NOTED ON THE CYCLONIC SIDE OF THE STRONG UPPER JET FROM MANITOBA INTO THE CORN BELT. UPSTREAM RADAR IMAGERY AND OBSERVATIONS ACROSS MN HAVE INDICATED SOME SNOW SHOWERS WITH THESE. ADD TO THAT SOME MORNING SUNSHINE ACROSS PARTS OF OUR CWA...AND WE SHOULD QUICKLY DESTABILIZE IN THE IMMEDIATE LOW-LEVELS UNDER THESE FEATURES. NAM AND RAP FORECAST BUFR SOUNDINGS FOR OUR FORECAST NOON TEMPS BOTH YIELD ALMOST 100 J/KG OF CAPE. WET BULB ZEROS WERE ANALYZED ON LAST NIGHTS RAOBS AND FORECAST BY TODAYS SOUNDINGS TO BE ONLY AROUND 1000 FT AGL. SO WOULD EXPECT ANY ISOLATED DEVELOPMENT TO BE MAINLY SNOW SHOWERS/FLURRIES. ITS POSSIBLE A COUPLE OF THESE PRODUCE BRIEF MODERATE RATES...BUT WOULD BE VERY TEMPORARY LASTING. HIGHS TODAY SHOULD BE LOWER TO MID 40S BASED ON CLIMATOLOGY FOR 850MB TEMPS OF AROUND -6C AND CONSIDERING THAT CLOUDS SHOULD FILL IN BY AFTERNOON. SOME FLURRIES MAY LINGER THIS EVENING...BUT TOUGH TO PLACE WHERE THOSE COULD BE RIGHT NOW. ALSO CHALLENGING TO FORESEE THE EVOLUTION OF THE CLOUD FIELD TONIGHT...WITH SOME INEVITABLE STRATOCU HOLES AND MAYBE EVEN EVENTUALLY FULL CLEARING LATE. SO MINS COULD VARY QUITE A BIT...BUT EXPECTING WIDESPREAD 20S IN OUTLYING AREAS. THURSDAY AND FRIDAY...THE IMPRESSIVE...IN FACT NEAR RECORD COLD AIR AT 850MB FOR THIS TIME OF YEAR...WILL MOVE OVER THE REGION ON THURSDAY AND THURSDAY NIGHT. THE MINIMUM 850MB TEMPERATURE ON THE DVN/ILX UPPER AIR PERIODS OF RECORD ARE RIGHT AROUND THE FORECAST OF -10C. SO THIS SETS THE STAGE FOR POTENTIAL RECORD COLD ON THU NIGHT WHEN A CLEAR SKY IS PROBABLE AND LIKELY RAPID DECOUPLING IN THE EVENING SHOULD ALLOW FOR QUICK DIMINISHING OF WINDS. WITH THU HIGHS AGAIN ONLY IN THE LOWER...TO POSSIBLY MID 40S...THE LOW STARTING POINT GOING INTO THE NIGHT WILL ALSO HELP. HAVE THU NIGHT LOWS FORECAST IN THE LOWER TO MID 20S...WITH LIKELY SOME UPPER TEENS IF THE LOWER 20S ARE WIDESPREAD. DOWNTOWN CHICAGO MAY ALSO SEE THEIR FIRST FREEZE. FRIDAY WILL HAVE A SLOW MODERATION IN TEMPS AND THEN RETURN FLOW FRIDAY NIGHT...WHICH IS WELL AGREED UPON IN GUIDANCE...LOOKS TO WARM TEMPS OVERNIGHT INTO SATURDAY. THIS WEEKEND AND EARLY NEXT WEEK...GUIDANCE BEGINS TO QUICKLY SHOW SPREAD THROUGH THIS PERIOD...BUT FOR THE MOST IS IN STRONG AGREEMENT OF A COLD FRONT DROPPING THROUGH ON SATURDAY. IF EARLY ENOUGH THIS MAY BRING AN AFTERNOON DROP IN TEMPERATURES. NOT MUCH THERE FOR FORCING OR SATURATION IN CURRENT GUIDANCE TO SUPPORT ANY POPS WITH THIS. AS THE TRAIN OF SYSTEMS IN NW FLOW ACROSS CANADA CONTINUES...A STRONG COLD FRONT APPROACHES THE AREA BY MONDAY...BUT THIS GETS HUNG UP AS AN UPPER LOW DIGS IN THE WESTERN U.S. AND FORCES HEIGHT RISES OVER THE REGION. THIS FRONT IS WIDELY DISAGREED UPON ON GUIDANCE AND SHOULD SERVE AS A PRETTY GOOD FOCUS FOR PRECIP WHERE IT BEGINS TO LIFT NORTH AS A WARM FRONT. TEMPS MAY BE MUCH COOLER UNDER THIS PRECIP...BUT TO THE SOUTH AT OR MAYBE EVEN ABOVE NORMAL. MTF && .CLIMATE... 450 AM CDT RECORD LOW TEMPERATURES IN OUTLYING AREAS MAY BE APPROACHED OR SET FRIDAY MORNING IF CLOUDS DEPART AS FORECAST. FOR CHICAGO...THE CLIMATE PERIOD OF RECORD INCLUDES SOME COLDER YEARS IN THE 1880S...WITH THE RECORD LOW BEING IN THE TEENS WHICH WILL VERY LIKELY NOT BE APPROACHED AT OHARE. BUT FOR OUR OTHER LONG TERM CLIMATE SITE OF ROCKFORD WHICH DATES BACK TO 1905...IT IS VERY POSSIBLE. RECORD LOW FOR ROCKFORD ON OCTOBER 25TH: 23 (1987) MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * NONE. JEE //DISCUSSION...UPDATED 06Z... LOW PRESSURE IS OVER SOUTHERN INDIANA WHILE HIGH PRESSURE IS SLIDING DOWN THE CENTRAL PLAINS. A WEAK SURFACE TROUGH HAS CAUSED WINDS TO BECOME W TO WSW EARLY THIS MORNING...BUT EXPECTING NW WINDS FOR THE REST OF TODAY. SKIES HAVE ALSO CLEARED OUT FOR A BIT WITH LIGHT WINDS CAUSING SHALLOW GROUND FOG AT A FEW LOCATIONS...PRIMARILY WHERE SNOW FELL EARLIER TODAY. GYY AND RFD APPEAR TO BE THE MORE FOG PRONE TERMINALS THIS MORNING AND HAVE THIS REFLECTED IN THE TAFS. THERE IS A WEAK BOUNDARY TO OUR NORTH JUST OVER THE WI STATE LINE WHERE DEWPOINTS ARE LOWER AND WINDS ARE OUT OF THE NW. EXPECTING VSBY TO IMPROVE...WINDS TO TURN NW AND PICK UP AS THIS BOUNDARY SINKS SOUTH. THE GRADIENT DOES TIGHTEN TODAY WITH NW WINDS GUSTING TO 15-20KT. WINDS WILL SUBSIDE THIS EVENING AND SKIES SHOULD THIN AND REMAIN VFR. CLOUDS MAY LINGER A BIT LONGER OVER GYY DEPENDING ON THE ORIENTATION OF LAKE EFFECT CLOUDS AND PRECIP...BUT OVERALL THINKING THE PRECIP WILL REMAIN EAST OF GYY. JEE //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE IN CIG AND WIND TRENDS...MEDIUM CONFIDENCE IN TIMING. JEE //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...CHANCE OF SHRA...OTHERWISE VFR. RODRIGUEZ && .MARINE... 315 AM CDT LOW PRESSURE IS OVER SE INDIANA WHILE A WEAK HIGH PRESSURE SINKS SOUTH OVER THE GULF COAST THIS EVENING. A SECOND WEAKER LOW OVER THE NORTHERN ROCKIES WILL ALSO TRAVEL DOWN THE PLAINS DISSIPATING OVER TEXAS THIS EVENING. A MUCH LARGER HIGH WILL BUILD OVER THE PLAINS TONIGHT THROUGH THURSDAY WITH NORTHWEST WINDS 15-25 KT EXPECTED ACROSS THE LAKE. THERE IS A CHANCE OF WATERSPOUTS ACROSS THE EASTERN SIDE OF THE LAKE AGAIN TODAY. HAZARDOUS WAVES ARE STILL EXPECTED ACROSS THE NEARSHORE WATERS TODAY AND WAVES WILL DIMINISH FOR A FEW HOURS LATE THIS EVENING ACROSS THE IL SIDE OF THE LAKE. HAZARDOUS WAVES WILL BUILD BACK EARLY THURSDAY MORNING SO ANOTHER SMALL CRAFT ADVISORY WILL BE NEEDED OVER THE IL NEARSHORE WATERS. WAVES FINALLY SUBSIDE TO BELOW SMALL CRAFT CRITERIA FRIDAY AFTERNOON. THE HIGH WILL SPREAD ACROSS THE SE US FRIDAY AND OVER THE WEEKEND WHILE A STRONG LOW PASSES OVER THE NORTHERN GREAT LAKES FRIDAY NIGHT AND SATURDAY. THE GRADIENT OVER THE LAKE WILL TIGHTEN DRAMATICALLY THEREFORE PUT LOW END GALES INTO THE FORECAST FOR FRIDAY NIGHT ACROSS THE LAKE. WINDS TURN NORTHWEST BEHIND THE LOWS COLD FRONT AND A BRIEF PERIOD OF NORTHWEST GALES IS ALSO POSSIBLE SATURDAY EVENING. GUIDANCE THEN BEGINS TO DIFFER SIGNIFICANTLY WITH WHAT THE NEXT HIGH AND LOW PAIR WILL DO. IN GENERAL LOOKING AT LIGHT WEST TO SOUTHWEST WINDS SUNDAY WITH A BACKDOOR COLD FRONT POSSIBLE LATE SUNDAY NIGHT INTO MONDAY. THEN EAST WINDS ARE EXPECTED EARLY NEXT WEEK. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM WEDNESDAY. && $$ 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
NWS CHICAGO/ROMEOVILLE IL
404 AM CDT WED OCT 23 2013 .DISCUSSION... 327 AM CDT AFTER LOOKING LIKE EARLY WINTER YESTERDAY IT WILL CONTINUE TO FEEL AS SUCH FOR A COUPLE DAYS...WITH THE FORECAST CHALLENGES TIED TO WELL BELOW NORMAL TEMPERATURES THESE NEXT FEW DAYS AND THEN SWINGING BACK TO CLOSER TO NORMAL THIS WEEKEND AND MAYBE MORE SO INTO EARLY NEXT WEEK. SYNOPSIS...THE PESKY CLIPPER SYSTEM FROM YESTERDAY IS RACING EASTWARD ACROSS THE UPPER OHIO VALLEY EARLY THIS MORNING. IN ITS WAKE 70M HEIGHT FALLS WERE OBSERVED AT 500MB LAST EVE AS THE LARGE SCALE LONG WAVE TROUGH ACROSS EASTERN/CENTRAL NORTH AMERICA CONTINUES TO BE RE-ESTABLISHED. THAT WILL REMAIN THE DOMINANT INFLUENCE ON THE LOCAL WEATHER PATTERN THIS WEEK...WITH PERSISTENT UPPER LEVEL NORTHWEST FLOW. A SERIES OF MID-LEVEL PERTURBATIONS WILL TRAVERSE IN THIS FLOW TODAY AND TONIGHT...AGAIN FURTHER LEADING TO LOWERED HEIGHTS AND COLD ADVECTION. WITH HIGH PRESSURE REMAINING ACROSS THE CENTRAL PLAINS ALLOWING FOR NO RETURN LOW-LEVEL FLOW...THIS ENABLES AN IDEAL REGIME FOR TEMPERATURES TO REMAIN COLD BY MID-AUTUMN STANDARDS. EARLY THIS MORNING...LOW-LEVEL CONVERGENCE OVER THE LAKE HAS BEEN NOTED IN OBSERVATIONS AND EARLIER WAS ANALYZED FROM MID-LAKE INTO PORTER COUNTY. BUT THIS HAS SHIFTED EAST AND MOST OF THE DEVELOPMENT IS MOVING SOUTHEAST FROM IT...SO ALL IN ALL MOST IF NOT ALL OF PORTER COUNTY LOOKS TO REMAIN FREE OF THE CONVECTIVE SHOWERS OVER THE LAKE THIS MORNING. TODAY AND TONIGHT...MULTIPLE COMPACT AND SHEARED SHORT WAVES ARE NOTED ON THE CYCLONIC SIDE OF THE STRONG UPPER JET FROM MANITOBA INTO THE CORN BELT. UPSTREAM RADAR IMAGERY AND OBSERVATIONS ACROSS MN HAVE INDICATED SOME SNOW SHOWERS WITH THESE. ADD TO THAT SOME MORNING SUNSHINE ACROSS PARTS OF OUR CWA...AND WE SHOULD QUICKLY DESTABILIZE IN THE IMMEDIATE LOW-LEVELS UNDER THESE FEATURES. NAM AND RAP FORECAST BUFR SOUNDINGS FOR OUR FORECAST NOON TEMPS BOTH YIELD ALMOST 100 J/KG OF CAPE. WET BULB ZEROS WERE ANALYZED ON LAST NIGHTS RAOBS AND FORECAST BY TODAYS SOUNDINGS TO BE ONLY AROUND 1000 FT AGL. SO WOULD EXPECT ANY ISOLATED DEVELOPMENT TO BE MAINLY SNOW SHOWERS/FLURRIES. ITS POSSIBLE A COUPLE OF THESE PRODUCE BRIEF MODERATE RATES...BUT WOULD BE VERY TEMPORARY LASTING. HIGHS TODAY SHOULD BE LOWER TO MID 40S BASED ON CLIMATOLOGY FOR 850MB TEMPS OF AROUND -6C AND CONSIDERING THAT CLOUDS SHOULD FILL IN BY AFTERNOON. SOME FLURRIES MAY LINGER THIS EVENING...BUT TOUGH TO PLACE WHERE THOSE COULD BE RIGHT NOW. ALSO CHALLENGING TO FORESEE THE EVOLUTION OF THE CLOUD FIELD TONIGHT...WITH SOME INEVITABLE STRATOCU HOLES AND MAYBE EVEN EVENTUALLY FULL CLEARING LATE. SO MINS COULD VARY QUITE A BIT...BUT EXPECTING WIDESPREAD 20S IN OUTLYING AREAS. THURSDAY AND FRIDAY...THE IMPRESSIVE...IN FACT NEAR RECORD COLD AIR AT 850MB FOR THIS TIME OF YEAR...WILL MOVE OVER THE REGION ON THURSDAY AND THURSDAY NIGHT. THE MINIMUM 850MB TEMPERATURE ON THE DVN/ILX UPPER AIR PERIODS OF RECORD ARE RIGHT AROUND THE FORECAST OF -10C. SO THIS SETS THE STAGE FOR POTENTIAL RECORD COLD ON THU NIGHT WHEN A CLEAR SKY IS PROBABLE AND LIKELY RAPID DECOUPLING IN THE EVENING SHOULD ALLOW FOR QUICK DIMINISHING OF WINDS. WITH THU HIGHS AGAIN ONLY IN THE LOWER...TO POSSIBLY MID 40S...THE LOW STARTING POINT GOING INTO THE NIGHT WILL ALSO HELP. HAVE THU NIGHT LOWS FORECAST IN THE LOWER TO MID 20S...WITH LIKELY SOME UPPER TEENS IF THE LOWER 20S ARE WIDESPREAD. DOWNTOWN CHICAGO MAY ALSO SEE THEIR FIRST FREEZE. FRIDAY WILL HAVE A SLOW MODERATION IN TEMPS AND THEN RETURN FLOW FRIDAY NIGHT...WHICH IS WELL AGREED UPON IN GUIDANCE...LOOKS TO WARM TEMPS OVERNIGHT INTO SATURDAY. THIS WEEKEND AND EARLY NEXT WEEK...GUIDANCE BEGINS TO QUICKLY SHOW SPREAD THROUGH THIS PERIOD...BUT FOR THE MOST IS IN STRONG AGREEMENT OF A COLD FRONT DROPPING THROUGH ON SATURDAY. IF EARLY ENOUGH THIS MAY BRING AN AFTERNOON DROP IN TEMPERATURES. NOT MUCH THERE FOR FORCING OR SATURATION IN CURRENT GUIDANCE TO SUPPORT ANY POPS WITH THIS. AS THE TRAIN OF SYSTEMS IN NW FLOW ACROSS CANADA CONTINUES...A STRONG COLD FRONT APPROACHES THE AREA BY MONDAY...BUT THIS GETS HUNG UP AS AN UPPER LOW DIGS IN THE WESTERN U.S. AND FORCES HEIGHT RISES OVER THE REGION. THIS FRONT IS WIDELY DISAGREED UPON ON GUIDANCE AND SHOULD SERVE AS A PRETTY GOOD FOCUS FOR PRECIP WHERE IT BEGINS TO LIFT NORTH AS A WARM FRONT. TEMPS MAY BE MUCH COOLER UNDER THIS PRECIP...BUT TO THE SOUTH AT OR MAYBE EVEN ABOVE NORMAL. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 09Z... * NONE. JEE //DISCUSSION...UPDATED 06Z... LOW PRESSURE IS OVER SOUTHERN INDIANA WHILE HIGH PRESSURE IS SLIDING DOWN THE CENTRAL PLAINS. A WEAK SURFACE TROUGH HAS CAUSED WINDS TO BECOME W TO WSW EARLY THIS MORNING...BUT EXPECTING NW WINDS FOR THE REST OF TODAY. SKIES HAVE ALSO CLEARED OUT FOR A BIT WITH LIGHT WINDS CAUSING SHALLOW GROUND FOG AT A FEW LOCATIONS...PRIMARILY WHERE SNOW FELL EARLIER TODAY. GYY AND RFD APPEAR TO BE THE MORE FOG PRONE TERMINALS THIS MORNING AND HAVE THIS REFLECTED IN THE TAFS. THERE IS A WEAK BOUNDARY TO OUR NORTH JUST OVER THE WI STATE LINE WHERE DEWPOINTS ARE LOWER AND WINDS ARE OUT OF THE NW. EXPECTING VSBY TO IMPROVE...WINDS TO TURN NW AND PICK UP AS THIS BOUNDARY SINKS SOUTH. THE GRADIENT DOES TIGHTEN TODAY WITH NW WINDS GUSTING TO 15-20KT. WINDS WILL SUBSIDE THIS EVENING AND SKIES SHOULD THIN AND REMAIN VFR. CLOUDS MAY LINGER A BIT LONGER OVER GYY DEPENDING ON THE ORIENTATION OF LAKE EFFECT CLOUDS AND PRECIP...BUT OVERALL THINKING THE PRECIP WILL REMAIN EAST OF GYY. JEE //ORD AND MDW CONFIDENCE...UPDATED 09Z... * HIGH CONFIDENCE IN CIG AND WIND TRENDS...MEDIUM CONFIDENCE IN TIMING. JEE //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...CHANCE OF SHRA...OTHERWISE VFR. RODRIGUEZ && .MARINE... 315 AM CDT LOW PRESSURE IS OVER SE INDIANA WHILE A WEAK HIGH PRESSURE SINKS SOUTH OVER THE GULF COAST THIS EVENING. A SECOND WEAKER LOW OVER THE NORTHERN ROCKIES WILL ALSO TRAVEL DOWN THE PLAINS DISSIPATING OVER TEXAS THIS EVENING. A MUCH LARGER HIGH WILL BUILD OVER THE PLAINS TONIGHT THROUGH THURSDAY WITH NORTHWEST WINDS 15-25 KT EXPECTED ACROSS THE LAKE. THERE IS A CHANCE OF WATERSPOUTS ACROSS THE EASTERN SIDE OF THE LAKE AGAIN TODAY. HAZARDOUS WAVES ARE STILL EXPECTED ACROSS THE NEARSHORE WATERS TODAY AND WAVES WILL DIMINISH FOR A FEW HOURS LATE THIS EVENING ACROSS THE IL SIDE OF THE LAKE. HAZARDOUS WAVES WILL BUILD BACK EARLY THURSDAY MORNING SO ANOTHER SMALL CRAFT ADVISORY WILL BE NEEDED OVER THE IL NEARSHORE WATERS. WAVES FINALLY SUBSIDE TO BELOW SMALL CRAFT CRITERIA FRIDAY AFTERNOON. THE HIGH WILL SPREAD ACROSS THE SE US FRIDAY AND OVER THE WEEKEND WHILE A STRONG LOW PASSES OVER THE NORTHERN GREAT LAKES FRIDAY NIGHT AND SATURDAY. THE GRADIENT OVER THE LAKE WILL TIGHTEN DRAMATICALLY THEREFORE PUT LOW END GALES INTO THE FORECAST FOR FRIDAY NIGHT ACROSS THE LAKE. WINDS TURN NORTHWEST BEHIND THE LOWS COLD FRONT AND A BRIEF PERIOD OF NORTHWEST GALES IS ALSO POSSIBLE SATURDAY EVENING. GUIDANCE THEN BEGINS TO DIFFER SIGNIFICANTLY WITH WHAT THE NEXT HIGH AND LOW PAIR WILL DO. IN GENERAL LOOKING AT LIGHT WEST TO SOUTHWEST WINDS SUNDAY WITH A BACKDOOR COLD FRONT POSSIBLE LATE SUNDAY NIGHT INTO MONDAY. THEN EAST WINDS ARE EXPECTED EARLY NEXT WEEK. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM WEDNESDAY. && $$ 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
NWS CHICAGO/ROMEOVILLE IL
330 AM CDT WED OCT 23 2013 .DISCUSSION... 327 AM CDT AFTER LOOKING LIKE EARLY WINTER YESTERDAY IT WILL CONTINUE TO FEEL AS SUCH FOR A COUPLE DAYS...WITH THE FORECAST CHALLENGES TIED TO WELL BELOW NORMAL TEMPERATURES THESE NEXT FEW DAYS AND THEN SWINGING BACK TO CLOSER TO NORMAL THIS WEEKEND AND MAYBE MORE SO INTO EARLY NEXT WEEK. SYNOPSIS...THE PESKY CLIPPER SYSTEM FROM YESTERDAY IS RACING EASTWARD ACROSS THE UPPER OHIO VALLEY EARLY THIS MORNING. IN ITS WAKE 70M HEIGHT FALLS WERE OBSERVED AT 500MB LAST EVE AS THE LARGE SCALE LONG WAVE TROUGH ACROSS EASTERN/CENTRAL NORTH AMERICA CONTINUES TO BE RE-ESTABLISHED. THAT WILL REMAIN THE DOMINANT INFLUENCE ON THE LOCAL WEATHER PATTERN THIS WEEK...WITH PERSISTENT UPPER LEVEL NORTHWEST FLOW. A SERIES OF MID-LEVEL PERTURBATIONS WILL TRAVERSE IN THIS FLOW TODAY AND TONIGHT...AGAIN FURTHER LEADING TO LOWERED HEIGHTS AND COLD ADVECTION. WITH HIGH PRESSURE REMAINING ACROSS THE CENTRAL PLAINS ALLOWING FOR NO RETURN LOW-LEVEL FLOW...THIS ENABLES AN IDEAL REGIME FOR TEMPERATURES TO REMAIN COLD BY MID-AUTUMN STANDARDS. EARLY THIS MORNING...LOW-LEVEL CONVERGENCE OVER THE LAKE HAS BEEN NOTED IN OBSERVATIONS AND EARLIER WAS ANALYZED FROM MID-LAKE INTO PORTER COUNTY. BUT THIS HAS SHIFTED EAST AND MOST OF THE DEVELOPMENT IS MOVING SOUTHEAST FROM IT...SO ALL IN ALL MOST IF NOT ALL OF PORTER COUNTY LOOKS TO REMAIN FREE OF THE CONVECTIVE SHOWERS OVER THE LAKE THIS MORNING. TODAY AND TONIGHT...MULTIPLE COMPACT AND SHEARED SHORT WAVES ARE NOTED ON THE CYCLONIC SIDE OF THE STRONG UPPER JET FROM MANITOBA INTO THE CORN BELT. UPSTREAM RADAR IMAGERY AND OBSERVATIONS ACROSS MN HAVE INDICATED SOME SNOW SHOWERS WITH THESE. ADD TO THAT SOME MORNING SUNSHINE ACROSS PARTS OF OUR CWA...AND WE SHOULD QUICKLY DESTABILIZE IN THE IMMEDIATE LOW-LEVELS UNDER THESE FEATURES. NAM AND RAP FORECAST BUFR SOUNDINGS FOR OUR FORECAST NOON TEMPS BOTH YIELD ALMOST 100 J/KG OF CAPE. WET BULB ZEROS WERE ANALYZED ON LAST NIGHTS RAOBS AND FORECAST BY TODAYS SOUNDINGS TO BE ONLY AROUND 1000 FT AGL. SO WOULD EXPECT ANY ISOLATED DEVELOPMENT TO BE MAINLY SNOW SHOWERS/FLURRIES. ITS POSSIBLE A COUPLE OF THESE PRODUCE BRIEF MODERATE RATES...BUT WOULD BE VERY TEMPORARY LASTING. HIGHS TODAY SHOULD BE LOWER TO MID 40S BASED ON CLIMATOLOGY FOR 850MB TEMPS OF AROUND -6C AND CONSIDERING THAT CLOUDS SHOULD FILL IN BY AFTERNOON. SOME FLURRIES MAY LINGER THIS EVENING...BUT TOUGH TO PLACE WHERE THOSE COULD BE RIGHT NOW. ALSO CHALLENGING TO FORESEE THE EVOLUTION OF THE CLOUD FIELD TONIGHT...WITH SOME INEVITABLE STRATOCU HOLES AND MAYBE EVEN EVENTUALLY FULL CLEARING LATE. SO MINS COULD VARY QUITE A BIT...BUT EXPECTING WIDESPREAD 20S IN OUTLYING AREAS. THURSDAY AND FRIDAY...THE IMPRESSIVE...INFACT NEAR RECORD COLD AIR AT 850MB FOR THIS TIME OF YEAR...WILL MOVE OVER THE REGION ON THURSDAY AND THURSDAY NIGHT. THE MINIMUM 850MB TEMPERATURE ON THE DVN/ILX UPPER AIR PERIODS OF RECORD ARE RIGHT AROUND THE FORECAST OF -10C. SO THIS SETS THE STAGE FOR POTENTIAL RECORD COLD ON THU NIGHT WHEN A CLEAR SKY IS PROBABLE AND LIKELY RAPID DECOUPLING IN THE EVENING SHOULD ALLOW FOR QUICK DIMINISHING OF WINDS. WITH THU HIGHS AGAIN ONLY IN THE LOWER...TO POSSIBLY MID 40S...THE LOW STARTING POINT GOING INTO THE NIGHT WILL ALSO HELP. HAVE THU NIGHT LOWS FORECAST IN THE LOWER TO MID 20S...WITH LIKELY SOME UPPER TEENS IF THE LOWER 20S ARE WIDESPREAD. DOWNTOWN CHICAGO MAY ALSO SEE THEIR FIRST FREEZE. FRIDAY WILL HAVE A SLOW MODERATION IN TEMPS AND THEN RETURN FLOW FRIDAY NIGHT...WHICH IS WELL AGREED UPON IN GUIDANCE...LOOKS TO WARM TEMPS OVERNIGHT INTO SATURDAY. THIS WEEKEND AND EARLY NEXT WEEK...GUIDANCE BEGINS TO QUICKLY SHOW SPREAD THROUGH THIS PERIOD...BUT FOR THE MOST IS IN STRONG AGREEMENT OF A COLD FRONT DROPPING THROUGH ON SATURDAY. IF EARLY ENOUGH THIS MAY BRING AN AFTERNOON DROP IN TEMPERATURES. NOT MUCH THERE FOR FORCING OR SATURATION IN CURRENT GUIDANCE TO SUPPORT ANY POPS WITH THIS. AS THE TRAIN OF SYSTEMS IN NW FLOW ACROSS CANADA CONTINUES...A STRONG COLD FRONT APPROACHES THE AREA BY MONDAY...BUT THIS GETS HUNG UP AS AN UPPER LOW DIGS IN THE WESTERN U.S. AND FORCES HEIGHT RISES OVER THE REGION. THIS FRONT IS WIDELY DISAGREED UPON ON GUIDANCE AND SHOULD SERVE AS A PRETTY GOOD FOCUS FOR PRECIP WHERE IT BEGINS TO LIFT NORTH AS A WARM FRONT. TEMPS MAY BE MUCH COOLER UNDER THIS PRECIP...BUT TO THE SOUTH AT OR MAYBE EVEN ABOVE NORMAL. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * NONE. JEE //DISCUSSION...UPDATED 06Z... LOW PRESSURE IS OVER SOUTHERN INDIANA WHILE HIGH PRESSURE IS SLIDING DOWN THE CENTRAL PLAINS. A WEAK SURFACE TROUGH HAS CAUSED WINDS TO BECOME W TO WSW EARLY THIS MORNING...BUT EXPECTING NW WINDS FOR THE REST OF TODAY. SKIES HAVE ALSO CLEARED OUT FOR A BIT WITH LIGHT WINDS CAUSING SHALLOW GROUND FOG AT A FEW LOCATIONS...PRIMARILY WHERE SNOW FELL EARLIER TODAY. GYY AND RFD APPEAR TO BE THE MORE FOG PRONE TERMINALS THIS MORNING AND HAVE THIS REFLECTED IN THE TAFS. THERE IS A WEAK BOUNDARY TO OUR NORTH JUST OVER THE WI STATE LINE WHERE DEWPOINTS ARE LOWER AND WINDS ARE OUT OF THE NW. EXPECTING VSBY TO IMPROVE...WINDS TO TURN NW AND PICK UP AS THIS BOUNDARY SINKS SOUTH. THE GRADIENT DOES TIGHTEN TODAY WITH NW WINDS GUSTING TO 15-20KT. WINDS WILL SUBSIDE THIS EVENING AND SKIES SHOULD THIN AND REMAIN VFR. CLOUDS MAY LINGER A BIT LONGER OVER GYY DEPENDING ON THE ORIENTATION OF LAKE EFFECT CLOUDS AND PRECIP...BUT OVERALL THINKING THE PRECIP WILL REMAIN EAST OF GYY. JEE //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN CIG AND WIND TRENDS...MEDIUM CONFIDENCE IN TIMING. JEE //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...CHANCE OF SHRA...OTHERWISE VFR. RODRIGUEZ && .MARINE... 315 AM CDT LOW PRESSURE IS OVER SE INDIANA WHILE A WEAK HIGH PRESSURE SINKS SOUTH OVER THE GULF COAST THIS EVENING. A SECOND WEAKER LOW OVER THE NORTHERN ROCKIES WILL ALSO TRAVEL DOWN THE PLAINS DISSIPATING OVER TEXAS THIS EVENING. A MUCH LARGER HIGH WILL BUILD OVER THE PLAINS TONIGHT THROUGH THURSDAY WITH NORTHWEST WINDS 15-25 KT EXPECTED ACROSS THE LAKE. THERE IS A CHANCE OF WATERSPOUTS ACROSS THE EASTERN SIDE OF THE LAKE AGAIN TODAY. HAZARDOUS WAVES ARE STILL EXPECTED ACROSS THE NEARSHORE WATERS TODAY AND WAVES WILL DIMINISH FOR A FEW HOURS LATE THIS EVENING ACROSS THE IL SIDE OF THE LAKE. HAZARDOUS WAVES WILL BUILD BACK EARLY THURSDAY MORNING SO ANOTHER SMALL CRAFT ADVISORY WILL BE NEEDED OVER THE IL NEARSHORE WATERS. WAVES FINALLY SUBSIDE TO BELOW SMALL CRAFT CRITERIA FRIDAY AFTERNOON. THE HIGH WILL SPREAD ACROSS THE SE US FRIDAY AND OVER THE WEEKEND WHILE A STRONG LOW PASSES OVER THE NORTHERN GREAT LAKES FRIDAY NIGHT AND SATURDAY. THE GRADIENT OVER THE LAKE WILL TIGHTEN DRAMATICALLY THEREFORE PUT LOW END GALES INTO THE FORECAST FOR FRIDAY NIGHT ACROSS THE LAKE. WINDS TURN NORTHWEST BEHIND THE LOWS COLD FRONT AND A BRIEF PERIOD OF NORTHWEST GALES IS ALSO POSSIBLE SATURDAY EVENING. GUIDANCE THEN BEGINS TO DIFFER SIGNIFICANTLY WITH WHAT THE NEXT HIGH AND LOW PAIR WILL DO. IN GENERAL LOOKING AT LIGHT WEST TO SOUTHWEST WINDS SUNDAY WITH A BACKDOOR COLD FRONT POSSIBLE LATE SUNDAY NIGHT INTO MONDAY. THEN EAST WINDS ARE EXPECTED EARLY NEXT WEEK. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM WEDNESDAY. && $$ 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
NWS CHICAGO/ROMEOVILLE IL
1240 AM CDT WED OCT 23 2013 .DISCUSSION... 905 PM CDT HAVE BEEN LOOKING AT THE POTENTIAL FOR GREATER SNOW ACCUMULATION IN PARTS OF NORTHWEST INDIANA OVERNIGHT THAN THE 0.4 INCHES OR SO REPRESENTED IN LATEST FORECAST GRIDS. AFTER INTERNAL DISCUSSION AND COORDINATION WITH OUR NEIGHBOR IWX...FEEL THAT THERMODYNAMICS CERTAINLY SUPPORT POTENTIAL FOR A PERIOD OF HEAVY SNOW ESPECIALLY IN PORTER COUNTY...AND MAINLY INLAND AWAY FROM THE MILD LAKE WATERS...BUT THERE ARE MULTIPLE UNCERTAINTIES THAT WOULD MAKE IT HARD TO PIN DOWN WHERE AND WHEN THESE ACCUMULATIONS MIGHT OCCUR. FIRST QUESTION IS DEGREE OF COOLING UNDER THE CLOUD LAYER AND HOW SUPPORTIVE THE PROFILE WOULD BE TO AN ALL SNOW PTYPE. TEMPERATURES IN THE SATURATED LAYER ALOFT DO NOT APPEAR TO BE EXCESSIVELY COLD...AND LOW LEVEL WET BULBS IN FCST SOUNDINGS STAY IN THE 2-3C RANGE UNTIL NEAR THE END OF THE EVENT TOWARD MORNING...SUGGESTING SUPPORT FOR A WET RAIN AND SNOW MIX. NEXT QUESTION IS WHERE BANDS MIGHT SET UP AND HOW LONG THEY WOULD REMAIN IN THE SAME POSITION. AN INCH PER HOUR WOULD BE A DECENT RATE BUT BANDS MAY NOT REMAIN OVER THE SAME LOCATION FOR TOO LONG. THIRD WILDCARD IS POSSIBLE DEVELOPMENT OF A MESOLOW ALONG THE EASTERN SHORE OF THE LAKE WHICH WOULD ENHANCE FORCING BUT THROW GREATER UNCERTAINTY INTO THE LOCATION ISSUE. FOR ALL THE REASONS LISTED...WILL MAINTAIN EXISTING FORECAST FOR NOW BUT CONTINUE TO MONITOR EVOLUTION OF CELLS ALREADY SEEN TO BE FORMING ACROSS NORTHERN PORTIONS OF THE LAKE. LATEST TRENDS ACROSS NORTHERN LOWER MI...WITH RAIN AT FRANKFORT AND TRAVERSE CITY ALONG THE SHORE AND WITH LIGHT SNOW FARTHER INLAND AT GRAYLING...GIVE A HINT OF WHAT WE ARE EXPECTING LATER TONIGHT AND TOWARD DAWN. LENNING //PREV DISCUSSION... 309 PM...FORECAST CONCERNS REMAIN PRECIP TYPE WITH CLIPPER SYSTEM THROUGH THIS EVENING ALONG WITH LAKE EFFECT PRECIP AND TYPE FOR NORTHWEST INDIANA LATER TONIGHT INTO WEDNESDAY MORNING. CENTER OF LOW PRESSURE JUST NORTH OF ST. LOUIS THIS AFTERNOON AND WILL TURN EAST THIS EVENING REACHING LOUISVILLE OVERNIGHT. HEAVIEST BAND OF PRECIP SHIFTED FROM THE QUAD CITIES THIS MORNING TO CURRENTLY ALONG THE I-80 CORRIDOR. STILL GETTING A MIX OF RAIN AND SNOW HERE AT LOT...WHICH IS JUST NORTH OF THIS HEAVIER BAND. STILL POSSIBLE TO SEE SOME CHANGEOVER OR BURSTS OF SNOW WITH THIS AREA AS IT SHIFTS EAST. RECENTLY RECEIVED A REPORT OF ONE INCH OF SNOW IN NORTHEAST LASALLE COUNTY WITH THIS BAND...THUS SLUSHY ACCUMULATIONS OF UP TO AN INCH WILL BE POSSIBLE AS IT MOVES EAST...GENERALLY BETWEEN I-80 AND THE KANKAKEE RIVER BUT WILL ALSO BE LOCALIZED. BUT WITH DEWPOINTS IN THE LOWER/MID 30S...EXPECT PREVAILING PRECIP TYPE OUTSIDE OF THIS BAND TO BE MAINLY RAIN WITH MIXED LIGHT SNOW. AS PRECIP WINDS DOWN THIS EVENING...POSSIBLE TO SEE VERY LIGHT SNOW OR FLURRIES MAYBE MIXED WITH SOME LIGHT DRIZZLE AS PRECIP ENDS FROM NORTHWEST TO SOUTHEAST THROUGH THE EVENING. WINDS TURN NORTHERLY OVER THE LAKE THIS EVENING AND OVERNIGHT WITH SOME CONVERGENCE EXPECTED OVER THE SOUTHEASTERN QUARTER OF THE LAKE. HAVE GENERALLY MAINTAINED CURRENT FORECAST WITH CAT POPS INTO PORTER COUNTY OVERNIGHT. VERY DIFFICULT TO DETERMINE HOW FAR WEST THIS LAKE EFFECT PLUME WILL MOVE. IF IT DOES MOVE FAR ENOUGH WEST TO IMPACT PORTER COUNTY...ITS DURATION WILL BE FAIRLY SHORT AS WINDS TURN BACK MORE NORTHWESTERLY WEDNESDAY MORNING...PUSHING THE PRECIP FURTHER EAST. PROBABLY MORE DIFFICULT THAN LOCATION OR TIMING WILL BE PRECIP TYPE. HEAVIER PRECIP BAND WILL LIKELY SWITCH OVER TO SNOW BUT WITH LAKE WATER TEMPERATURES STILL IN THE 50S AND AIR TEMPERATURES LIKELY TO STILL BE IN THE LOWER 40S...THIS MAY LIMITED SNOW REACHING THE SURFACE. THE FURTHER INLAND THIS BAND PUSHES...THE MOVE LIKELY PRECIP TYPE WILL BE SNOW. WILL CARRY JUST MINOR ACCUMULATIONS FOR NOW...POSSIBLY UP TO AN INCH...BUT THIS WILL NEED TO BE MONITORED THROUGH THE NIGHT. NEXT AND WEAKER CLIPPER SYSTEM MOVES MUCH FURTHER SOUTHWEST OF THE AREA FROM WESTERN IOWA TO SOUTHERN ILLINOIS...THUS EXPECTING DRY WEATHER INTO THIS WEEKEND BUT TEMPERATURES WILL REMAIN BELOW NORMAL WITH HIGHS ONLY IN THE 40S THROUGH FRIDAY AND LOWS IN THE 20S/LOWER 30S. BY FRIDAY NIGHT HOWEVER...LOW PRESSURE WILL MOVE ACROSS THE NORTHERN LAKES...ALLOWING SOME WEAK WARM ADVECTION TO OCCUR HELPING TO WARM BOTH HIGHS/LOWS INTO THIS WEEKEND. THERE IS BETTER AGREEMENT BETWEEN THE GFS/ECMWF WITH A BRIEF SHOT OF COOLER AIR SATURDAY NIGHT BEHIND A TRAILING COLD FRONT THEN ANOTHER WARM UP LATER SUNDAY INTO MONDAY WITH TEMPERATURES WELL INTO THE 50S AND DEPENDING ON CLOUD COVER AND THE EXTENT OF HOW WARM THE AIRMASS IS ADVECTING INTO THE REGION...POSSIBLE TO SEE HIGHS INTO THE 60S. LOW PRESSURE DEVELOPS OVER THE PLAINS MONDAY AND SPREADS LIFTS NORTHEAST ACROSS THE LAKES REGION TUESDAY INTO WEDNESDAY. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * NONE. JEE //DISCUSSION...UPDATED 06Z... LOW PRESSURE IS OVER SOUTHERN INDIANA WHILE HIGH PRESSURE IS SLIDING DOWN THE CENTRAL PLAINS. A WEAK SURFACE TROUGH HAS CAUSED WINDS TO BECOME W TO WSW EARLY THIS MORNING...BUT EXPECTING NW WINDS FOR THE REST OF TODAY. SKIES HAVE ALSO CLEARED OUT FOR A BIT WITH LIGHT WINDS CAUSING SHALLOW GROUND FOG AT A FEW LOCATIONS...PRIMARILY WHERE SNOW FELL EARLIER TODAY. GYY AND RFD APPEAR TO BE THE MORE FOG PRONE TERMINALS THIS MORNING AND HAVE THIS REFLECTED IN THE TAFS. THERE IS A WEAK BOUNDARY TO OUR NORTH JUST OVER THE WI STATE LINE WHERE DEWPOINTS ARE LOWER AND WINDS ARE OUT OF THE NW. EXPECTING VSBY TO IMPROVE...WINDS TO TURN NW AND PICK UP AS THIS BOUNDARY SINKS SOUTH. THE GRADIENT DOES TIGHTEN TODAY WITH NW WINDS GUSTING TO 15-20KT. WINDS WILL SUBSIDE THIS EVENING AND SKIES SHOULD THIN AND REMAIN VFR. CLOUDS MAY LINGER A BIT LONGER OVER GYY DEPENDING ON THE ORIENTATION OF LAKE EFFECT CLOUDS AND PRECIP...BUT OVERALL THINKING THE PRECIP WILL REMAIN EAST OF GYY. JEE //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN CIG AND WIND TRENDS...MEDIUM CONFIDENCE IN TIMING. JEE //OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z... THURSDAY...VFR. FRIDAY...VFR. SATURDAY...VFR. SUNDAY...VFR. MONDAY...CHANCE OF SHRA...OTHERWISE VFR. RODRIGUEZ && .MARINE... 237 PM CDT FAIRLY STEADY STATE CONDITIONS EXPECTED THROUGH THE REMAINDER OF THE WEEK. LOW PRESSURE WILL CONTINUE TO SPIN AND GRADUALLY SHIFT EAST OVER EASTERN CANADA WHILE HIGH PRESSURE BUILDS SOUTHEAST FROM THE NORTHERN PLAINS TODAY TO THE LOWER TO MID MISSISSIPPI VALLEY BY FRIDAY. THE PERSISTENT MODERATE NORTHWESTERLY GRADIENT THROUGH THE PERIOD WILL RESULT IN NORTHWEST WINDS OF 15 TO 25 KT OVER MOST OF THE LAKE THROUGH FRIDAY...WITH SOME MINOR UNDULATIONS AS WEAK PERTURBATIONS MOVE THROUGH THE REGION. WITH TEMPORARY WEAKER WINDS TODAY OVER THE SOUTHERN PORTIONS OF THE LAKE...WILL ALLOW THE SMALL CRAFT ADVISORY TO EXPIRE FOR THIS AFTERNOON...BUT NORTHERLY WINDS PICKING UP AGAIN OVERNIGHT WILL ALLOW WAVES TO ONCE AGAIN GROW...THUS WILL HOIST A NEW SMALL CRAFT ADVISORY GOING INTO EFFECT EARLY WEDNESDAY MORNING. LOW PRESSURE WILL DROP SOUTHEAST ACROSS THE CANADIAN PRAIRIES AND OVER LAKE SUPERIOR EARLY SATURDAY WITH WINDS AT LEAST BRIEFLY RETURNING TO SOUTHWEST FRIDAY NIGHT THROUGH LATE MORNING SATURDAY. A FRONT SWEEPING ACROSS THE LAKE SATURDAY AFTERNOON WILL THEN TURN WINDS BACK TO THE NORTHWEST THROUGH THE REMAINDER OF THE WEEKEND. TRANSIENT HIGH PRESSURE QUICKLY MOVES ACROSS THE LAKE MONDAY ALLOWING WINDS TO DIMINISH...BEFORE TURNING SOUTHEASTERLY AGAIN AHEAD OF A BROAD AREA OF LOW PRESSURE DEVELOPING OVER THE PLAINS. BMD && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ743-LMZ744-LMZ745...5 AM WEDNESDAY TO 3 PM FRIDAY. SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...5 AM WEDNESDAY TO 10 PM WEDNESDAY. && $$ 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 1158 PM CDT Tue Oct 22 2013 .DISCUSSION... ISSUED 902 PM CDT Tue Oct 22 2013 Getting a mix or rain and snow along and north of I-74 this evening. Current forecast has good handle on this and radar loop indicates it should be out of the area by midnight. Main concern is cloud cover and its effect on overnight lows. Satellite loops show more cloud cover than forecast would seem to indicate for later tonight. However, breaks seen in the overcast on satellite and think that temps will still drop, even if briefly to warrant a freeze warning overnight. Remainder of forecast looks fine except for cloud cover. So will be updating forecast for that and may look at overnight lows as well, but will not raise them too much, if at all. Update will be out shortly. Auten && .AVIATION... ISSUED 1158 PM CDT Tue Oct 22 2013 Complex cloud pattern is occurring overnight and making for a interesting aviation forecast for the first several hours at each site. PIA has already become VFR but remains cloudy. All other sites are IFR, but will likely see cig heights rise during the overnight hours. Question is when. Satellite loops gives some clue that IFR cigs will give way to little bit higher cigs during the overnight hours. Believe DEC and CMI could see lower MVFR conditions before VFR moves into the area, while BMI could see conditions improve right to VFR, but not until around 10z. SPI will start with lower MVFR and then improve to VFR around 09z. DEC and CMI should improve to VFR around 10z and 11z respectively. Once conditions improve, believe VFR conditions will remain through remainder of the TAF period. HRRR and NAM-WRF hint at some breaks in the cloud cover overnight or tomorrow, but current satellite loops shows lots of clouds over the area and upstream. Know this could change quickly, but will keep broken cigs at all sites through morning. CU rule indicates that CU should continue tomorrow afternoon but will add a TEMPO for scattered clouds for a few hours in the afternoon. Then broken clouds will continue tomorrow evening as the next weather system makes its way into the area. North to northwest winds will remain and then become more northwest to west tomorrow. Strongest winds will be tomorrow around 12-13 kts. Auten && .PREV DISCUSSION... ISSUED 210 PM CDT Tue Oct 22 2013 Latest surface analysis has low pressure just north of Quincy with a warm front extending from the low over extreme southwest Illinois. A large area of rain extended mainly north and east of the surface low with a narrow band of snow falling just north of our forecast area to the Quad Cities where a couple of inches of wet snow accumulated thru the morning hours. We did receive a report of some snow in Altona in northern Knox county this morning but temperatures were well into the 30s at that time. The main forecast concern in the short term will be overnight low temps the next several nights with the potential for widespread freezing temperatures by tomorrow morning, and especially late Thu night into Friday morning when surface high pressure will be approaching our area. In the longer range...our cold pattern will begin to break down as the deep vortex north of the Great Lakes shifts off the north and east of the region by late in the weekend and into early next week with our 500 mb flow turning more southwesterly increasing not only our temperatures but also our rain chances. SHORT TERM...Tonight through Friday Surface low forecast by models to track east-southeast to near Mattoon by early this evening, and then finally east of our forecast area by midnight. With the track a bit further north than previous forecasts had indicated, the low levels look to stay too warm to support any snow before we lose the ice crystals in the upper portions of the cloud. The better 700-500 mb QG forcing shifts off to our east rather quickly early this evening with quite a bit of wrap around moisture/clouds in the wake of the system. Forecast soundings and time-height cross sections indicate some clearing taking place by midnight over our northwest and then working east and south later tonight. The NAM-WRF 850 temps showing some decent cold air advection overnight as the surface wave shifts into Kentucky by Wednesday morning. With the clear sky and diminishing winds overnight, it appears the setup would support more widespread freezing temperatures than what was experienced last night so went ahead and issued a Freeze Warning for areas north of I-70. Morning lows will range from roughly 25 to 30 degrees over a larger area and for a longer duration than last night. Cloud cover will be slower to clear out along and south of I-70 so will hold off any headlines in that area tonight as lows dip into the lower to middle 30s. Next fast moving clipper will track southeast into the region by late Wednesday morning into the afternoon hours with an increase in clouds during the day. However, the moisture and lift associated with this upper wave is not nearly as strong as today`s forcing, as a result, will continue with only slight chance pops during the late morning thru the early evening hours. As far as overnight temps late Wed night into Thursday morning, forecast soundings continue to indicate quite a bit of low level moisture in the wake of the clipper system on Wednesday, so guid temps not as cold as tonight across the southeast with lows in the low to mid 30s once again. It appears the better chance for widespread freezing temperatures in the southeast would be on Friday morning as another cold high pressure area approaches from the west. Morning lows will drop to between 27 and 30 degrees in areas along and south of I-70, as a result, a Freeze Watch has been issued for the far southeast for the early morning hours of Friday. After a cold start on Friday, high pressure will keep the weather cool and dry across the entire area as we head into the weekend. LONG TERM...Saturday through Tuesday Medium range models continue to suggest a major pattern change to take place early next week as the deep vortex north of the Great Lakes shifts off to our east and north. 500 mb heights will be on the rise across our area in response to a trof that is forecast to develop to our west and close off a low in the Rockies by late Tuesday and track SSE into the southern Plains. This will bring in much warmer air to the region with afternoon temperatures approaching 60 on Monday and well into the 60s by Tuesday. Shower chances will begin to increase, especially Monday night through Tuesday as a series of shortwaves are forecast to eject from the trof to our southwest and track northeast into forecast area. Smith && .ILX WATCHES/WARNINGS/ADVISORIES... FREEZE WATCH from late Thursday night through Friday morning FOR ILZ062-063-066>068-071>073. FREEZE WARNING until 8 AM CDT Wednesday FOR ILZ027>031-036>038- 040>057-061. && $$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
431 AM EDT WED OCT 23 2013 .SYNOPSIS... ISSUED AT 417 AM EDT WED OCT 23 2013 A SERIES OF DISTURBANCES WILL MOVE THROUGH THE REGION OVER THE NEXT COUPLE OF DAYS. LAKE EFFECT RAIN SHOWERS CAN BE EXPECTED ACROSS PORTIONS OF NORTHWESTERN INDIANA AND SOUTHWESTERN LOWER MICHIGAN OVER THE NEXT COUPLE OF DAYS AS THE COLD NORTHWESTERLY FLOW CONTINUES OVER THE WARM WATERS OF LAKE MICHIGAN. SNOW MAY BE MIXED AT TIMES WITH THE SHOWERS THIS MORNING AND AGAIN TONIGHT. AFTERNOON HIGH TEMPERATURES WILL CLIMB INTO THE LOWER TO MIDDLE 40S. OVERNIGHT LOWS WILL DROP BACK INTO THE LOWER 30S...EXCEPT MID 30S ALONG THE LAKESHORE. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 417 AM EDT WED OCT 23 2013 COMPACT UPPER LOW HAS BEEN STEADY PROGRESS ESE DURING THE EVENING/OVERNIGHT HOURS...WITH CENTER SOMEWHERE AROUND INDIANAPOLIS. WHILE RAIN HAS BEEN THE DOMINANT PTYPE...SOME REPORTS OF SNOW OR SLEET OCCURRING HAVE BEEN RECEIVED IN OUR FAR SOUTHERN COUNTIES WITH SOME SLUSHY LIGHT ACCUMULATIONS NOTED IN SOME AREAS. THIS AREA WILL CONTINUE TO PULL AWAY BY 12Z WEDS. FURTHER NORTH...FLOW IS BECOMING MORE N AND NW AND ALLOWING FOR EXPANDING DEVELOPMENT OF LAKE EFFECT SHOWERS ACROSS MUCH OF LAKE MI. THE GREATEST CONCENTRATION HAS BEEN RESIDING ALONG THE EASTERN HALF AND SOMEWHAT INLAND INTO WESTERN LWR MI. LAKE INDUCED INSTABILITY REMAINS IN THE MODERATE TO EXTREME CATEGORY (SFC-850 MB/SFC-700 MB DELTA T VALUES OF LOW 20S AND LOW 30S RESPECTIVELY) WITH LAKE BASED CAPES APPROACHING 1000 J/KG. AN OCCASIONAL REPORT OF SLEET/GRAUPEL HAVE COME IN ASSOCIATED WITH THE STRONGER SHOWERS. AS THIS SHOULD CONTINUE...HAVE ADDED MENTION OF SLEET IN CATEGORICAL AREAS. IN TERMS OF TIMING AND COVERAGE HRRR HAS A NICE HANDLE ON BOTH PRECIP TO THE SOUTH AND EVOLUTION OF LAKE EFFECT SHOWERS. EXPECTING A CHAOTIC PATTERN TO THE LAKE EFFECT SHOWERS INITIALLY AS SFC OBS INDICATING MESO LOW THAT WAS ADVERTISED ON HIGH RES MODELS PAST COUPLE OF DAYS HAS TAKEN SHAPE OVER THE SOUTHERN PART OF THE LAKE. THIS FEATURE WILL WORK SLOWLY SOUTH AND MOVE ONSHORE IN THE 9 TO 12Z WINDOW. HAVE EXPANDED CAT POPS FURTHER EAST INTO ALL OF BERRIEN AS WELL AS PART OF CASS AND ST JOE INDIANA COUNTIES TO COVER UPSTREAM TRENDS. CHANCES FOR SNOW/GRAUPEL WILL DECREASE AFTER 15Z AS TEMPS BEGIN TO WARM INTO THE 40S. FOR THIS AFTERNOON...HI RES MODELS SEEM TO LOWER OVERALL DEPTH OF MSTR BUT STILL LINGER A DECENT AMOUNT WHERE STRONGEST OMEGA RESIDES. IN ADDITION...INSTABILITY WILL REMAIN UNCHANGED. WHILE SOME CONCERN THAT COVERAGE COULD DIMINISH SOMEWHAT IN THE 19 TO 23Z RANGE WITH THIS DECREASE IN MSTR...WILL GO WITH INSTABILITY MAKING UP THE DIFFERENCE WITH HIGH LIKELY/LOW CAT POPS WARRANTED (AND EXPANDED SLIGHTLY TO BETTER REFLECT EXPECTED FLOW). NEXT WAVE OF INTEREST...PRESENTLY DIVING SE THROUGH THE DAKOTAS...WILL APPROACH LATER THIS AFTERNOON AND TONIGHT. TRACK OF THIS FEATURE WILL AGAIN BE TO THE SW OF THE AREA... TRACKING THROUGH WESTERN IOWA INTO SOUTHERN ILLINOIS. CLOUD COVER WILL INCREASE NORTHEAST OF THE FEATURE ACROSS THE AREA BUT PRECIP CHANCES LOOK TO BE CONFINED DOWNWIND OF LK MI AS NW FLOW WILL INCREASE...AND BOUNDARY LAYER MOISTURE WILL PICK UP ONCE AGAIN. INCREASED POPS SOMEWHAT TO HIGH END LIKELY FOR NOW BUT SUBSEQUENT INCREASE TO CAT POPS MAY BE NEEDED IN LATER FORECASTS. LOWS WILL DROP INTO THE LOW 30S IN MOST SPOTS AWAY FROM THE LAKE WHICH MAY RESULT IN AN GREATER CHANCE OF SNOW VS RAIN BUT GIVEN LAKE PROCESSES PRECIP MAY REMAIN MAINLY RAIN. WILL KEEP MIX MENTION FOR NOW. && .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 417 AM EDT WED OCT 23 2013 LARGE SCALE TROUGH EXPECTED TO REMAIN OVER THE GREAT LAKES THROUGH THE WEEKEND BEFORE PATTERN BEGINS TO RELOAD WITH RISING HEIGHTS AND MODERATING TEMPERATURES NEXT WEEK. LAKE EFFECT RAIN AND SNOW SHOWERS WILL BE PRIMARY CONCERN DURING THE BEGINNING OF THE LONG TERM PERIOD. WEAK SHORT WAVE AND SURFACE TROUGH TO PASS ACROSS THE AREA EARLY THU MORNING. THIS WILL HELP INCREASE SFC-700 DELTA T VALUES TO OVER 30 PROVIDING EXTREME INSTABILITY FROM LAKE MICHIGAN. LAKE INDUCED CAPE VALUES RISE TO OVER 800 J/KG WITH NEARLY UNIDIRECTIONAL NW FETCH. 1000-850MB RH REMAINS ABOVE 80 PERCENT SO SEE LITTLE REASON THAT LAKE EFFECT SHOWERS WILL NOT BE ONGOING. HAVE RAISED POPS TO CATEGORICAL ACROSS MI COUNTIES NEAR THE LAKE AND TAPERED FURTHER INLAND. PCPN TYPE WILL BE QUITE DIFFICULT AROUND THE LAKE AS MODIFIED BOUNDARY LAYER SHOULD KEEP PCPN MAINLY RAIN NEAR THE LAKE WITH A MIX OF RAIN AND SNOW INLAND WHERE THERMAL PROFILES MORE FAVORABLE FOR SNOW. HEAVIER SHOWERS TO BRING PERIODS OF MAINLY SNOW AND SLEET BUT FOR NOW HAVE KEPT FORECAST AS A RAIN/SNOW MIX GIVEN DIFFICULTY OF NAILING DOWN THESE MESOSCALE DETAILS AT THIS TIME RANGE. SOME MINOR SNOW ACCUMULATIONS ON GRASSY SURFACES WILL BE POSSIBLE AWAY FROM THE LAKE...ESPECIALLY THU NIGHT WITH DIURNAL COOLING AND CONTINUED EXTREME INSTABILITY AND FAVORABLE TRAJECTORIES. GIVEN THE INSTABILITY EXPECT SOME RATHER IMPRESSIVE RAINFALL TOTALS WHERE BANDS ARE PERSISTENT. LAKE EFFECT TO BEGIN WINDING DOWN LATER FRIDAY MORNING AS FLOW BACKS AHEAD OF NEXT APPROACHING SHORT WAVE AND INVERSION HEIGHTS LOWER WITH DECREASING MOISTURE. DELTA T VALUES REMAIN FAVORABLE FOR SOME LIGHTER SHOWERS CLOSER TO LAKE AND EVEN FRIDAY NIGHT WITH SOUTHWEST FLOW AFFECTING FAR NORTHERN BERRIEN COUNTY. ATMOSPHERE BECOMING RATHER DRY BY THIS TIME SO OPTED FOR JUST A SLIGHT CHANCE POP WITH SFC-850MB DELTA T VALUES STILL AROUND 20. A BRIEF MODERATION IN TEMPS EXPECTED SAT AHEAD OF NEXT SHORT WAVE AND COLD FRONT. TEMPS WILL STRONGLY DEPEND ON HOW FAST CLOUDS MOVE IN SATURDAY. SOUTHERN AREAS SHOULD SEE LOW TO MID 50S WHILE NORTHERN AREAS CLIMB TO NEAR 50. THIS CLIPPER WILL BRING ANOTHER BRIEF SHOT OF COLDER AIR AND A CHANCE FOR ADDITIONAL LAKE EFFECT RAIN SHOWERS. MEDIUM RANGE MODELS IN GOOD AGREEMENT ON LARGE SCALE PATTERN FOR EARLY NEXT WEEK AS WEST COAST ENERGY BEGINS TO CARVE OUT A NEW TROUGH OVER THE WESTERN CONUS. THIS ALLOWS HEIGHTS TO RISE OVER THE MIDWEST WITH MODERATING TEMPERATURES MONDAY AND TUESDAY. A COLD FRONT WILL SAG SOUTH AND BECOME NEARLY STATIONARY EITHER ACROSS OR JUST NORTH OF OUR AREA AS IT BECOMES PARALLEL TO MID LEVEL FLOW. THIS FRONT WILL BE FOCUS FOR SHOWERS MONDAY INTO TUESDAY AND EVEN WEDNESDAY OF NEXT WEEK. A LOT TO WATCH WITH THIS EVOLUTION AS WARM SECTOR WILL LIKELY BE RELATIVELY WARM FOR OCTOBER AND A NICE BAROCLINIC ZONE WILL SET NEAR OUR AREA. SURFACE WAVE DEVELOPMENT AROUND DAY 7 WILL HELP BACK WINDS AND STRONG 100 KNOT JET LOOKS TO RACE TOWARD THE AREA. KINEMATICS LOOK FAVORABLE FOR SEVERE WEATHER IN THE MIDWEST OR MID SOUTH BUT INSTABILITY REMAINS A BIG UNKNOWN. HOWEVER...CLIMATOLOGY FAVORS A SECONDARY SEVERE WEATHER PEAK IN OCTOBER FOR WEAK INSTABILITY/HIGH SHEAR SEVERE WEATHER EVENTS. CERTAINLY WORTH WATCHING NEXT SEVERAL DAYS IN MODEL EVOLUTION. PATTERN REMAINS QUITE ACTIVE GIVEN NUMEROUS PACIFIC/ASIAN CYCLONES OVER THE LAST FEW WEEKS WHICH HAVE HELPED AMPLIFY THE MID LEVEL FLOW AND DOWNSTREAM PATTERN OVER THE CONUS. LONGER RANGE OUTLOOK FOR DAY 7-10 ALSO LOOKS QUITE INTERESTING WITH WEST CONUS LOW EJECTION TOWARD THE AREA BY LATE NEXT WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 126 AM EDT WED OCT 23 2013 AREA OF LIGHT RAIN WAS PERSISTING AT KFWA...WITH TRENDS SUGGESTING A SLOW SE MOVEMENT OVER THE NEXT COUPLE OF HOURS. IFR CONDITIONS WILL PERSIST UNTIL THE DEPARTURE OF THE RAIN WITH RAPID IMPROVEMENT THEREAFTER. AT KSBN...VFR CONDITIONS IN PLACE FOR THE TIME BEING. LAKE EFFECT RAIN (SNOW?) SHOWERS WERE SLOWLY EXPANDING ACROSS LK MI AND BEGINNING TO COME ONSHORE IN BERRIEN AND LAPORTE COUNTIES. WITH TIME SOME OF THESE MAY MAKE THEIR WAY TO KSBN...BUT OVERALL TIMING/IMPACT IS STILL A CHALLENGE. AHEAD OF THESE SOME LIGHT RAIN/DRIZZLE HAS BEEN OBSERVED SO TAFS ARE STARTING OUT WITH VFR SHOWERS WITH A DOWNWARD TREND IN THE 9 TO 10Z WINDOW AS ACTIVITY WORKS INLAND MORE AND LAKE EFFECT BEGINS TO EXPAND. FURTHER CHANGES MAY BE NEEDED AT KSBN OVERNIGHT INTO MONDAY MORNING AS THE LAKE EFFECT EVOLVES. HAVE LEFT A VCSH IN FOR THE AFTERNOON WITH ANY ACTIVITY (ASSUMING ANY IS LEFT WITH DRY AIR MOVING IN BRIEFLY BEFORE THE NEXT WAVE) LIKELY REMAINING JUST NORTH OF KSBN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT FRIDAY FOR LMZ043-046. && $$ SYNOPSIS...FISHER SHORT TERM...FISHER LONG TERM...LASHLEY AVIATION...FISHER VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
306 AM MDT WED OCT 23 2013 .SHORT TERM...(TODAY THROUGH FRIDAY NIGHT) ISSUED AT 305 AM MDT WED OCT 23 2013 LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW STILL IN PLACE ACROSS PLAINS WITH LARGE SCALE TROUGH ACROSS THE EASTERN CONUS. MAIN STORM TRACK IS STILL OVER NORTHER PLAINS AND UPPER MISSISSIPPI VALLEY...WELL OUTSIDE OF OUR AREA OF CONCERN. AT THE SURFACE A BACKDOOR COLD FRONT HAS STALLED OVER OUR CWA...TO BE NEAR KGLD. NORTHEAST OF THIS FEATURE 10-12KFT CLOUD DECK ASSOCIATED WITH EMBEDDED ENERGY WITHIN MEAN UPPER FLOW IS MOVING ACROSS THE NORTHEASTERN PART OF OUR CWA. NW FLOW WILL SHIFT EAST WITH CONFLUENT PATTERN/LARGE SCALE SUBSIDENCE REMAINING IN PLACE THROUGH FRIDAY. QUASI-STATIONARY FRONT OVER THE CWA WILL SHIFT NORTHEAST TODAY AND THEN BACK TO THE WEST OF THE CWA TONIGHT...BEFORE LIFTING TO THE NORTH AGAIN BY FRIDAY. BREEZY CONDITIONS ARE ANTICIPATED DURING THE DAYTIME PERIODS TIED TO PEAK HEATING/MIXING. SURFACE HIGH PRESSURE BEGINS TO BUILD SOUTH TONIGHT BEHIND THIS FRONT WITH LIGHT EASTERLY FLOW AND INCREASING BL MOISTURE SUPPORTING POSSIBLE STRATUS/FOG. MODELS NEVER COMPLETELY SATURATE BOUNDARY LAYER...HOWEVER CONSIDERING THE PATTERN/CONCEPTUAL MODEL SUPPORTING FOG AND MET GUIDANCE SHOWING REDUCED VISIBILITIES I DECIDED TO ADD PATCHY FOG MENTION LATE FRIDAY NIGHT THROUGH THURSDAY MORNING. HIGHS WILL GENERALLY BE SEASONAL TODAY AND FRIDAY (HIGHS 60S TO NEAR 70F) WITH COOLER TEMPS THURSDAY AS A RESULT OF THE FRONT FURTHER WEST...WHEN AIR MASS OVER CWA WILL MAINLY SUPPORT HIGHS ONLY IN THE 50S. BY FRIDAY NIGHT A WEAK CUTOFF LOW WILL MOVE FROM THE FOUR CORNERS REGION INTO THE SOUTHERN PLAINS. CURRENT TRACK KEEPS MOISTURE AND BEST LARGE SCALE SUPPORT WELL SOUTH OF OUR CWA. WHILE THERE IS SOME ELEVATED INSTABILITY ACROSS SW KS THAT COULD SUPPORT A FEW SPRINKLES AS FAR NORTH AS WICHITA/GREELEY COUNTIES...CONFIDENCE IS IN CONDITIONS REMAINING DRY WITH THIS FEATURE FRIDAY NIGHT. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 305 AM MDT WED OCT 23 2013 WARM WEEKEND AHEAD OF A STRONG COLD FRONT EARLY NEXT WEEK WHICH WILL BRING THE CHANCE FOR WINTRY PRECIP AND COLD TEMPS. SATURDAY AND SUNDAY WILL BE MILD WITH WEAK RIDGING MOVING ACROSS THE CENTRAL HIGH PLAINS LATE SATURDAY. SUNDAY WILL BE QUITE WARM WITH HIGHS IN THE 70S DUE TO WARM AIR ADVECTION AND FULL SUNSHINE. FAIRLY HIGH CONFIDENCE EARLY NEXT WEEK A STRONG COLD FRONT WILL SURGE SOUTH THROUGH THE HIGH PLAINS BRINGING MUCH COLDER AIR AND CHANCES FOR PRECIP. MODEL DIFFERENCES ARE STILL FAIRLY LARGE EVEN WHEN COMPARING MODELS RUN-TO-RUN...WITH LEAST CONFIDENCE IN PRECIP AND TIMING. THE COLD IS A DIFFERENT STORY WITH ALL GLOBAL GUIDANCE SHOWING A SURGE OF COLD AIR MOVING SOUTH BY MID-WEEK NEXT WEEK...BUT AGAIN WITH TIMING DIFFERENCES. GENERALLY LEFT THE MODEL BLEND AS-IS BESIDES INCREASING SOME POPS SLIGHTLY. AT THIS POINT IT LOOKS LIKE THE FRONT WILL PUSH THROUGH LATE MONDAY WITH PRECIP BEGINNING AS SNOW...THEN POSSIBLY CHANGING TO RAIN/SNOW MIX ON TUESDAY AFTERNOON. DID NOT SPEND TO MUCH TIME NIT-PICKING TIMING AND PTYPE AT THIS TIME RANGE DUE TO COARSE TIME RESOLUTION OF GRIDS AT THIS RANGE....AND AT THIS POINT IT LOOKS LIKE THE PTYPES SHOULD BE STRAIGHTFORWARD /RAIN AND SNOW/. THE 00Z GFS IS A LITTLE CONCERNING WITH A WARM LAYER ALOFT TUESDAY...BUT GIVEN THE COMPLEXITY OF THE SET-UP AM NOT CONCERNED ABOUT IT JUST YET. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1057 PM MDT TUE OCT 22 2013 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. WINDS WILL SHIFT THROUGH THE PERIOD UNTIL TOMORROW MORNING WHEN A STRONGER FRONTAL PASSAGE IS EXPECTED. AT THAT TIME THE WINDS WILL BECOME GUSTY FROM THE NORTH TO NORTHWEST. THOSE WILL CONTINUE UNTIL LATE IN THE AFTERNOON WHEN THEY DECREASE DRAMATICALLY. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...JJM AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
101 AM EDT WED OCT 23 2013 .SYNOPSIS... A WEAK RIDGE OF HIGH PRESSURE WILL PREVAIL ACROSS THE REGION INTO THIS MORNING...THEN THEN A SMALL AREA OF SURFACE LOW PRESSURE WILL SLIDE WELL SOUTH OF THE REGION LATE TODAY AND THIS EVENING. AN UPPER LEVEL TROUGH WILL BUILD INTO THE EAST FROM QUEBEC THURSDAY AND MOVE EAST FRIDAY AS COLDER AIR ARRIVES. && .NEAR TERM /THROUGH TODAY/... 1230 AM UPDATE: MADE CHGS TO FCST HRLY CLD CVR AND TEMPS BASED ON LATEST SAT IMAGERY AND SFC OBS. LASTLY...WE HAD TO LOWER WIND SPEEDS AND GUSTS IN THE BROAD VLYS OF OUR FA...WITH WIND SPEEDS SHARPLY DIMINISHING SINCE THE COLD FRONT PASSAGE WITH THE WEAKENING OF THE SFC PRES GRAD. 941 PM UPDATE: A STRONG COLD FRONT BISECTS THE SOUTHEAST THIRD OF THE CWA AS OF 930 PM/0130Z. A LINE OF SHOWERS WITH THE FRONT EXTEND FROM JUST SOUTH OF HOULTON TO THE PENOBSCOT BAY. THE LAST OF THE SHOWERS SHOULD CLEAR WASHINGTON COUNTY BETWEEN MIDNIGHT AND 1 AM. BRIEF GUSTY WIND WILL LIKELY CONTINUE TO ACCOMPANY THE FRONT WITH A GUSTS TO AROUND 35 MPH POSSIBLE DURING THE FROPA. THE HRRR CONTINUES TO HAVE A VERY GOOD HANDLE ON THE AREA OF SHOWERS THIS EVENING. WILL UPDATE THE POP AND WIND GRIDS TO MATCH THE CURRENT AND EXPECTED CONDITIONS OVER THE NEXT FEW HOURS. OTHERWISE...NO SIGNIFICANT CHANGES ARE PLANNED FOR THIS UPDATE. 610 PM UPDATE: LOW PRES JUST EAST OF JAMES BAY WILL REMAIN QUASI- STATIONARY TONIGHT AND CONTINUE TO DEEPEN TO AROUND 985 MB BY 12Z WED. A PRE-FRONTAL TROUGH STRETCHES FROM ERN AROOSTOOK COUNTY TO NEAR BANGOR AT 22Z. THERE IS A LINE OF SHOWERS ASSOCIATED WITH THIS TROUGH. THERE IS A SECOND LINE OF SHOWERS WHICH ARE ASSOCIATED WITH A STRONG COLD THAT EXTENDS FROM AROUND FT KENT TO GREENVILLE. THIS FRONT WILL SWEEP ACROSS THE REMAINDER OF THE CWA THIS EVENING LIKELY MERGING WITH THE PRE-FRONTAL TROUGH. THE LAST OF THE SHOWERS SHOULD EXIT SOUTHEAST WASHINGTON COUNTY BY AROUND MIDNIGHT. IN THE WAKE OF THE FRONT A MUCH COLDER AIR MASS WILL SPREAD ACROSS THE REGION OVERNIGHT. MADE SOME TWEAKS TO POP/WX GRIDS BASED ON THE LATEST RADAR RETURNS. ALSO REMOVED THE MENTION OF THUNDER FOR THIS EVENING AS THERE HAVE NOT BEEN ANY CLOUD TO GROUND STRIKES NOR ANY IN CLOUD LIGHTNING. ORGNL DISC: AREA OF SHOWERS SETTING UP AHEAD OF THE APCHG COLD FRONT PER THE 18Z RADAR TREND. 18Z SFC ANALYSIS SHOWS A PRE- FRONTAL TROF OUR AHEAD OF THE COLD FRONT W/THE SHOWERS ALIGNED W/THE BOUNDARY. THE LATEST HRRR WAS DOING QUITE WELL W/THE PLACEMENT AND MOVEMENT OF THE PRECIP SHIELD. LAPS SOUNDINGS SHOWED SOME DESTABILIZATION MAINLY ACROSS THE CENTRAL HIGHLANDS AND INTERIOR DOWNEAST WHERE SOME HEATING AND THE BEST 0-6KM SHEAR EXISTS. CONTINUED TO CARRY ISOLD TSTMS IN THESE AREAS THROUGH 00Z. OTRW, SHOWERS AND GUSTY WINDS OF UP TO 35 MPH AREA POSSIBLE. LATEST RADAR VELOCITY DID SHOW 40 KTS AT 6K FT ACROSS THE CENTRAL HIGHLANDS AT 18Z. TEMPERATURES ARE PEAKED AND NOW WILL BEGIN TO FALL BACK AFTER 00Z WHEN THE COLD FRONT ARRIVES. SHOWERS WILL BE INTO NEW BRUNSWICK BY 02Z OR SO AND THEN PARTIAL CLEARING WILL BEGIN LATER THIS EVENING INTO THE OVERNIGHT HOURS. CAA WILL BRING BREEZY CONDITIONS FOR A WHILE UP THROUGH 06Z AND THEN WINDS WILL DROP OFF AS THE GRADIENT LOOSENS. COLD AIR TO ARRIVE BY WEDNESDAY MORNING W/READINGS BY 7 AM IN THE UPPER 20S TO AROUND 30 ACROSS THE NORTH AND WEST AND LOW/MID 30S INTERIOR DOWNEAST AND THE COAST. COLLABORATED W/NERFC AND LOWERED QPF AMOUNTS TO 0.15-0.30 ACROSS THE NORTHERN 1/2 OF THE CWA W/0.10 OR LESS FOR THE CENTRAL HIGHLANDS AND INTERIOR DOWNEAST. A CHILLY DAY ON WEDNESDAY W/SOME BRIEF RIDGING AND SUNSHINE. IT WILL FEEL SOMEWHAT LIKE A SHOCK TO THE SYSTEM AS DAYTIME HIGHS ARE EXPECTED TO BE IN THE UPPER 40S TO AROUND 50 NORTH AND WEST TO LOWER 50S DOWNEAST. DECIDED ON THE ECMWF MOS/GMOS BLEND FOR TEMPERATURES. && .SHORT TERM /TONIGHT THROUGH FRIDAY/... A DEEP TROUGH MOVING INTO THE EAST WILL USHER IN SOME VERY CHILLY AIR FOR THE LATTER PART OF THIS WEEK. A SMALL WAVE OF LOW PRESSURE TRACKING OFF THE MID ATLANTIC COAST AND SLIDING WELL SOUTH OF THE REGION MAY BRING SOME LIGHT RAIN TO DOWNEAST LOCATIONS EARLY WEDNESDAY EVENING. OTHERWISE, WEDNESDAY NIGHT WILL BE PARTLY CLOUDY AND BECOMING BREEZY AS THE GRADIENT SOUTH OF A LARGE LOW PRESSURE SYSTEM MOVING INTO EASTERN CANADA BEGINS TO EFFECT THE REGION. THIS WILL GIVE WAY TO A WINDY AND CHILLY DAY ON THURSDAY AS COLD AIR PULLING AROUND THE LOW FLOWS INTO THE STATE. SKIES WILL RANGE FROM PARTLY CLOUDY DOWNEAST TO OVERCAST IN STRATOCUMULUS CLOUDS ACROSS THE NORTH AND SOME LIGHT RAIN, OR POSSIBLY SNOW SHOWERS, MAY AFFECT NORTHERN AREAS ESPECIALLY OVER HIGHER ELEVATIONS. BREEZY AND CHILLY CONDITIONS WITH A MOSTLY CLOUDY SKY NORTH AND PARTIAL CLOUDINESS DOWNEAST WILL CONTINUE THURSDAY NIGHT INTO FRIDAY. SOME PATCHY LIGHT SHOWERS OR FLURRIES ARE POSSIBLE IN THE HIGHER ELEVATIONS IN THE WEST THURSDAY NIGHT OR FRIDAY. OTHERWISE, MAINLY DRY WEATHER WILL CONTINUE OVER THE AREA INTO FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A SHORTWAVE CASCADING INTO THE TROUGH FRIDAY NIGHT WILL DEVELOP LOW PRESSURE IN THE GREAT LAKES ON SATURDAY. CHILLY AIR WILL BE IN PLACE SATURDAY INTO SATURDAY EVENING AS THIS LOW APPROACHES WITH INCREASING CLOUDS. PRECIPITATION WILL SPREAD ACROSS THE REGION SATURDAY EVENING. CURRENT GUIDANCE INCLUDING THE GFS AND ECMWF ARE INDICATING THE AIR WILL LIKELY BE COLD ENOUGH TO SUPPORT SOME WET SNOW ACROSS THE NORTH AS THE PRECIPITATION MOVES IN SATURDAY EVENING. THE ECMWF HAS LOW LEVEL CRITICAL THICKNESSES BELOW 1300 AT 1000-850 MB, COLD ENOUGH TO SUPPORT SNOW, ACROSS THE NORTHERN HALF OT THE STATE SATURDAY EVENING. THE GFS HAS THE NORTHERN THIRD OF THE STATE COLD ENOUGH FOR SNOW. ALL OF THE GFS ENSEMBLE MEMBERS SUPPORT THICKNESSES COLD ENOUGH FOR SNOW OVER THE NORTH. THE CANADIAN MODEL, HOWEVER, INDICATES THICKNESSES WILL BE TOO WARM FOR SNOW. THE AIR IS EXPECTED TO WARM A BIT LATE SATURDAY NIGHT INTO SUNDAY MORNING AS THE LOW CENTER TRACKS ACROSS THE NORTHERN PART OF THE STATE SO ANY SNOW WOULD LIKELY TURN OVER TO RAIN. AN INCH OR TWO OF SNOW MAY FALL ACROSS THE NORTHERN PART OF THE STATE BEFORE THE CHANGE OVER WITH THE GREATEST CHANCES FOR SOME ACCUMULATION OVER ELEVATIONS ABOVE 700 FT. PRECIPITATION WILL END SUNDAY MORNING. ANOTHER SURGE OF CHILLY AIR WILL FOLLOW THE SYSTEM EARLY NEXT WEEK AS HIGH PRESSURE BUILDS IN FROM CANADA. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: A BRIEF PERIOD OF MVFR THIS EVENING W/THE COLD FROPA AND THEN VFR WEDNESDAY. SHORT TERM: A PERIOD OF MVFR POSSIBLE WED EVENING AT KBHB AND POSSIBLY KBGR WITH CONDITIONS TO IMPROVE TO VFR LATER WEDNESDAY NIGHT. VFR THURSDAY WITH CONDITIONS TO POSSIBLY LOWER TO MVFR IN STRATOCUMULUS CLOUDS ACROSS THE NORTH LATE THURSDAY INTO THURSDAY NIGHT AND REMAIN VFR DOWNEAST. VFR CONDITIONS ARE EXPECTED FRIDAY INTO SATURDAY. CONDITIONS WILL THEN LOWER TO IFR IN PRECIPITATION (RAIN AND SNOW) SAT NIGHT. && .MARINE... NEAR TERM: SEAS ARE 4 FT AT THE ERN MAINE SHELF AS OF 9 PM EDT. THE WIND AT THE ERN ME SHELF HAS BEEN LESS THAN 10 KNOTS OVER THE PAST SEVERAL HOURS. WILL CANCEL THE SCA WITH THIS UPDATE. A BRIEF WIND GUSTS MAY ACCOMPANY THE WIND SHIFT WITH THE FROPA OVER THE NEXT FEW HOURS...BUT ANY GUSTS WILL BE VERY SHORT LIVED. SHORT TERM: A STRONG SCA OR POSSIBLY A GALE WILL BE NEEDED FOR GUSTY WEST WINDS ON THURSDAY. AN SCA WILL LIKELY BE NEEDED THURSDAY NIGHT. WINDS SHOULD THEN BE BELOW SCA FRIDAY AND SATURDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...VJN SHORT TERM...BLOOMER LONG TERM...BLOOMER AVIATION...VJN/BLOOMER MARINE...VJN/BLOOMER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
506 AM EDT WED OCT 23 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 439 AM EDT WED OCT 23 2013 THE CWA IS UNDER THE WESTERN SIDE OF AN UPPER TROUGH COVERING THE THE GREAT LAKES REGION. THIS TROUGH IS ALLOWING COLD AIR TO SURGE SOUTH OVER THE AREA AND LEAD TO BELOW NORMAL TEMPERATURES OVER THE LAST COUPLE OF DAYS. AT THE SURFACE...A NEARLY STATIONARY LOW EAST OF JAMES BAY AND A HIGH PRESSURE RIDGE STRETCHING FROM THE CANADIAN PRAIRIES INTO THE NORTHERN PLAINS WILL CONTINUE TO PRODUCE NORTHWESTERLY FLOW OVER THE AREA OVER THE NEXT 24-36HRS. SNOW SHOWERS ACROSS THE AREA ARE FAIRLY DISORGANIZED AND BLOTCHY EARLY THIS MORNING AS WINDS HAVE BEEN BOUNCING AROUND DURING THE OVERNIGHT HOURS (DUE TO LAND BREEZES AND WEAK SURFACE TROUGH STRETCHING ACROSS THE WESTERN LAKE). THIS DISORGANIZATION IS ALSO LIKELY DUE TO MODELS SHOWING DEEPER MOISTURE TO BE LACKING OVER MUCH OF THE AREA AT THIS TIME (EVEN THOUGH 850MB TEMPS ANALYZED ON THE RAP ARE -8C). THE LAST HOUR OR SO HAS SEEN A SLIGHT INCREASE IN COVERAGE AND INTENSITY...LARGELY DUE TO THE POCKET OF MOISTURE THAT IS SLIDING OUT OF NORTHEAST MINNESOTA AND ASSOCIATED WITH WEAK SHORTWAVE ENERGY. THIS TREND WILL PROBABLY CONTINUE THROUGH THE NEXT COUPLE HOURS AND HAVE TRENDED POPS UP (FROM CURRENT SCATTERED COVERAGE) THROUGH THE MID MORNING HOURS. STRONGEST SHOWERS WILL LIKELY BE EAST OF MUNISING AND POTENTIALLY FOCUSED IN GOGEBIC/ONTONAGON COUNTIES WITH WINDS TRYING TO BACK SLIGHTLY AHEAD OF THE WEAK LAKE INDUCED SURFACE TROUGH OVER THE WESTERN LAKE EARLY THIS MORNING. HIGH RESOLUTION MODELS PICKING UP ON THIS IDEA IN THEIR PRECIP/REFLECTIVITY FIELDS AND LEADS TO INCREASED CONFIDENCE. ONCE DAYTIME HEATING TAKES HOLD AND POCKET OF DRIER AIR ALONG THE MINNESOTA/CANADA BORDER DROPS OVER THE AREA...THINK THE SHOWERS WILL DIMINISH SOME...ESPECIALLY OVER THE WEST WHERE THE FETCH IS SHORTER. ONE OTHER ITEM FOR THIS AFTERNOON...HELD ONTO SOME POPS OVER THE SOUTH CENTRAL...EVEN THOUGH THAT ISN/T A FAVORABLE LOCATION FOR LAKE EFFECT. FELT HAVING SLIGHT CHANCES WAS REASONABLE WITH THE MOISTURE AVAILABLE AND STEEPENING LAPSE RATES (SFC-850MB VALUES AROUND 9C/KM) WITH THE COLD AIR ALOFT. THIS SHOULD BE ENOUGH FOR SOME CONVECTIVE CLOUD DEVELOPMENT AND MAYBE A FEW SHOWERS WITH THE INCREASING MOISTURE. THAT POCKET OF DRIER AIR WILL DEPART AS A SHORTWAVE DROPS SOUTH FROM ONTARIO THIS AFTERNOON AND EVENING. THIS BRINGS ADDITIONAL LOW-MID LEVEL MOISTURE WITH IT AND WILL AID THE LAKE EFFECT SHOWERS THAT WILL BE ONGOING. IT WILL ALSO BRING ABOUT A SLIGHT WIND SHIFT TO MORE OF A NORTH-NORTHWEST DIRECTION AND PUSH THE ONGOING LAKE EFFECT SHOWERS TO THE WEST. BEST MOISTURE IS OVER THE EASTERN CWA...SO WOULD EXPECT THE STRONGEST SHOWERS THERE WITH THE GREATEST FETCH. MODELS ARE INDICATING THE WINDS SHIFT AIDING A DOMINATE BAND OVER THE EAST DURING THE EVENING (INITIALLY OVER FAR EASTERN LAKE SUPERIOR AND THEN SHIFTING SOUTHWEST TOWARDS GRAND MARAIS) WHICH WILL BE ASSISTED BY MOISTENING OFF LAKE NIPIGON. ONE NEGATIVE WITH THIS SHORTWAVE IS THAT IT DOES PULL SLIGHTLY WARMER 850MB TEMPS OVER THE AREA TONIGHT...RISING SLIGHTLY FROM -8C TODAY TO -6/-7C TONIGHT OVER THE EAST. THIS LEADS TO INCREASING LOW LEVEL TEMPS AND RISING WETBULB ZERO VALUES. 00Z NAM/GFS BUFKIT SOUNDINGS FOR KERY SHOW WETBULB ZERO VALUES RISING TO ALMOST 1.5KFT BY DAYBREAK...WHICH WOULD BE PRETTY MUCH RAIN. ALSO...MUNISING STAYED RIGHT AROUND 41 DEGREES EARLY THIS MORNING UNTIL THE LAND BREEZE KICKED IN AND SHIFTED THE WINDS TO THE SOUTHWEST (TEMP DROPPED TO 36 DEGREES). SINCE THE GRADIENT SHOULD BE TIGHTER TONIGHT...THINK THAT WILL KEEP TEMPS UP RIGHT ALONG THE SHORELINE. THEREFORE...AFTER SNOW DURING THE DAY...HAVE TRENDED TOWARDS A MIX OF RAIN/SNOW EAST OF A LINE FROM MUNISING TO MANISTIQUE. AS FOR SNOW AMOUNTS...THE RAIN/SNOW MIX CREATES UNCERTAINTY ALONG WITH SNOW RATIOS. HAVE KEPT SNOW RATIOS LOWER...TOWARDS 10-1...SINCE THE BEST FORCING CONTINUES TO BE BELOW THE DGZ AND ONLY THE TOP OF THE CLOUD IS WITHIN THE DGZ. AS WAS SEEN TODAY...THERE WILL PROBABLY BE PERIODS OF FLAKES AND ALSO SNOW GRAINS/PELLETS IN THE STRONGER SHOWERS DUE TO THE STRONG LIFT OF SUPER COOLED WATER RUNNING INTO THE SMALLER FLAKES ALOFT. FOR EXAMPLE...TODAY AT OUR OFFICE WE HAD 0.53 INCH OF LIQUID BUT THE SNOWFALL TOTAL WAS 2.2 INCHES. THUS...WONDERING IF THE CURRENT 10-1 FORECAST IS A LITTLE TOO HIGH OVER THE EAST AND MAY BE CLOSER TO A 7/8 TO 1. AS FOR SNOWFALL TOTALS...KEPT AMOUNTS AROUND AN INCH IN THE NW SNOW BELTS FOR TODAY (WITH LOCALIZED HIGHER AMOUNTS NEAR IRONWOOD AND THE PORKIES). THEN FOR TONIGHT...HAVE A GENERAL 1-3IN FOR THE SAME LOCATIONS...BUT LESSER AMOUNTS WHERE THE RAIN/SNOW MIX IS. SOME CONCERN FOR NEAR ADVISORY LEVEL SNOWFALL TONIGHT OVER THE EAST WITH THE DOMINATE BAND. BUT WITH THE UNCERTAINTY ON SNOW TYPE (FLAKE VS PELLET) AND ALSO SOME RAIN MIXING IN NEAR THE SHORELINE...DIDN/T HAVE ENOUGH CONFIDENCE TO ISSUE ONE FOR ALGER COUNTY AREA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 503 AM EDT WED OCT 23 2013 A BLOCKING RIDGE FROM THE ERN PACIFIC INTO WEST COAST WILL KEEP THE BROAD DOWNSTREAM TROUGH IN PLACE OVER THE CNTRL AND ERN CONUS THROUGH THE FCST PERIOD WITH CONTINUED BELOW NORMAL TEMPERATURES. SHORTWAVE TROUGHS IN THE NW FLOW THROUGH THE UPPER GREAT LAKES WILL SUPPORT PERIODS OF INCREASED LAKE EFFECT PCPN. THURSDAY...WITH 850 MB TEMPS AROUND -6C TO -7C AND 700 MB TEMPS AROUND -13C...INSTABILITY WILL REMAIN HIGH ENOUGH TO KEEP LAKE EFFECT PCPN GOING FOR LOCATIONS FAVORED BY NW FLOW. THE HIGHER RES MODELS INDICATED THAT A MORE DOMINANT BAND ORIGINATING OFF OF LAKE NIPIGON MAY DEVELOP THAT WOULD AFFECT THE AREA FROM NEAR MUNISING AND PICTURED ROCKS TO MANISTIQUE. EVEN THOUGH LOCAL QPF VALUES MAY APPROACH A QUARTER INCH...THE LONG FETCH ACROSS THE RELATIVELY WARM LAKE MAY BRING ENOUGH MARINE INFLUENCE (MODEL WET-BULB ZERO HEIGHTS 1000-1500 FT) TO BRING MAINLY RAIN NEAR THE SHORE AND A RAIN/SNOW/GRAUPEL MIX FARTHER INLAND. SNOW/WATER RATIOS ARE LIKELY TO BE LOW AS THE GREATEST UPWARD MOTION IS EXPECTED WELL BELOW THE 8K-10K FT DGZ. SNOW SHOWERS WILL ALSO CONTINUE INTO WRN UPPER MI BUT WITH SNOWFALL AMOUNTS AT OR BELOW AN INCH GIVEN THE SHORTER FETCH AND APPROACH OF MORE ACYC FLOW WITH THE RIDGE MOVING INTO THE UPPER MS VALLEY. THU NIGHT...WITH A WEAKER WIND FIELD...LAKE INDUCED TROUGHING WILL HELP TO KEEP THE FOCUS OF LAKE EFFECT PCPN FROM NEAR MUNISING INTO NW SCHOOLCRAFT COUNTY. LOW LEVEL TEMPS WILL REMAIN WARM ENOUGH TO SUPPORT A RAIN/SNOW MIX WHICH SHOULD LIMIT SNOW ACCUMULATIONS TO AN INCH OR LESS. OVER THE WEST...SNOW SHOWERS WILL BECOME SCATTERED AND DIMINISH AS INVERSION HEIGHT DROP AND DRIER AIR EDGES IN. FRI INTO SAT...THE GFS/ECMWF WERE IN GOOD AGREEMENT WITH THE CLIPPER SHORTWAVE TROUGH AND SFC LOW MOVING THROUGH THE NRN GREAT LAKES. THE GREATEST 285K-295K ISENTROPIC LIFT AND ASSOCIATED PCPN BAND AHEAD OF THE LOW IS EXPECTED TO MOVE THROUGH THE EAST HALF OF LAKE SUPERIOR AND UPPER MICHIGAN FRI NIGHT. CAA BEHIND THE LOW DROPPING 850 MB TEMPS BACK TO -7C WILL BRING ANOTHER ROUND OF LAKE EFFECT PCPN FOR NW FLOW FAVORED LOCATIONS FROM SAT AFTERNOON INTO SAT NIGHT. LOW LEVEL TEMPS WILL BE WARM ENOUGH FOR A RAIN/SNOW MIX...EXCEPT OVER THE HIGHER TERRAIN OF THE WEST HALF. SUN-TUE...MODEL DIFFERENCES BECOME MORE SIGNIFICANT. THE ECMWF IS FASTER WITH THE NEXT SHORTWAVE AND PUSHES LOWER HEIGHTS AND CONFLUENCE ZONE FARTHER SOUTH COMPARED TO THE GFS/GEM. SO...FCST CONFIDENCE IN LOCATION OF EVOLUTION OF PCPN CHANCES ASSOCIATED WITH THE DEVELOPING 800-600 FGEN ZONE MON AND AREA OF WAA ISENTROPIC LIFT INTO TUE IS LOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 136 AM EDT WED OCT 23 2013 ALTHOUGH CONDITIONS WILL REMAIN FAVORABLE FOR LAKE EFFECT -SHSN... DRIER AIR IN THE BOUNDARY LAYER AND VFR CLOUD BASES UPSTREAM OF LAKE SUPERIOR SUGGEST VFR CONDITIONS WILL LIKELY BE THE RULE AT ALL TERMINALS FOR MUCH OF THE OVERNIGHT. HOWEVER...CAN`T RULE OUT BRIEF MVFR IN -SHSN AT KIWD/KCMX. LATE IN THE NIGHT INTO THE MORNING... NOCTURNAL COOLING WILL PROVIDE A MORE FAVORABLE ENVIRONMENT FOR LAKE EFFECT -SHSN...AND WHEN COMBINED WITH SUBTLE SHORTWAVE DROPPING ACROSS THE AREA...EXPECT MVFR CONDITIONS TO BECOME MORE LIKELY AT KIWD/KCMX. NOT OUT OF THE QUESTION THAT THERE COULD BE BRIEF IFR VIS WITH HEAVIER SNOW SHOWERS AS WELL. WNW WIND FLOW WILL NOT BE FAVORABLE FOR MUCH MORE THAN OCNL FLURRIES...IF THAT...AT KSAW. MAY SEE A PERIOD OF MVFR CIGS WITH DAYTIME HEATING AT KSAW. OTHERWISE... ALL TERMINALS SHOULD RETURN TO PREVAILING VFR DURING THE AFTN. MVFR CIGS MAY RETURN THIS EVENING AS MODELS SHOW INCREASING MOISTURE IN THE BOUNDARY LAYER. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 439 AM EDT WED OCT 23 2013 WITH THE UPPER GREAT LAKES BETWEEN A LOW OVER WESTERN QUEBEC AND A HIGH PRESSURE RIDGE STRETCHING FROM THE CANADIAN PRAIRIES AND INTO THE NORTHERN PLAINS...EXPECT PERSISTENT NORTHWEST WINDS OF 15-25KTS THROUGH THURSDAY. THERE COULD BE SOME GUSTS TO 30KTS OVER THE EAST TONIGHT AS THE PRESSURE GRADIENT TIGHTENS SLIGHTLY. WINDS ARE EXPECTED TO DIMINISH AND BACK ON THURSDAY NIGHT AND FRIDAY...AS A HIGH PRESSURE RIDGE MOVES THROUGH THE UPPER GREAT LAKES. A CLIPPER SYSTEM WILL DIVE SOUTHEAST OUT OF CANADA ON FRIDAY NIGHT AND MOVE ACROSS EASTERN LAKE SUPERIOR. THIS WILL ONCE AGAIN SHIFT WINDS BACK TO THE NORTHWEST UP TO 30KTS FOR SATURDAY AND SATURDAY NIGHT...ESPECIALLY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL MOVE BACK INTO THE GREAT LAKES FOR SUNDAY...DECREASING THE WINDS BELOW 20KTS. FINALLY...WILL CONTINUE TO MENTION A SLIGHT CHANCE FOR WATERSPOUTS OVER THE SOUTHEAST PART OF LAKE SUPERIOR FOR THIS AFTERNOON INTO TONIGHT. WATERSPOUT NOMOGRAM INDICATES BORDERLINE POTENTIAL...BUT WITH STRONGER LAKE EFFECT SHOWERS OCCURRING DURING THAT TIME...FELT IT WAS WARRENTED TO KEEP IN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...JLB AVIATION...ROLFSON MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
440 AM EDT WED OCT 23 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 439 AM EDT WED OCT 23 2013 THE CWA IS UNDER THE WESTERN SIDE OF AN UPPER TROUGH COVERING THE THE GREAT LAKES REGION. THIS TROUGH IS ALLOWING COLD AIR TO SURGE SOUTH OVER THE AREA AND LEAD TO BELOW NORMAL TEMPERATURES OVER THE LAST COUPLE OF DAYS. AT THE SURFACE...A NEARLY STATIONARY LOW EAST OF JAMES BAY AND A HIGH PRESSURE RIDGE STRETCHING FROM THE CANADIAN PRAIRIES INTO THE NORTHERN PLAINS WILL CONTINUE TO PRODUCE NORTHWESTERLY FLOW OVER THE AREA OVER THE NEXT 24-36HRS. SNOW SHOWERS ACROSS THE AREA ARE FAIRLY DISORGANIZED AND BLOTCHY EARLY THIS MORNING AS WINDS HAVE BEEN BOUNCING AROUND DURING THE OVERNIGHT HOURS (DUE TO LAND BREEZES AND WEAK SURFACE TROUGH STRETCHING ACROSS THE WESTERN LAKE). THIS DISORGANIZATION IS ALSO LIKELY DUE TO MODELS SHOWING DEEPER MOISTURE TO BE LACKING OVER MUCH OF THE AREA AT THIS TIME (EVEN THOUGH 850MB TEMPS ANALYZED ON THE RAP ARE -8C). THE LAST HOUR OR SO HAS SEEN A SLIGHT INCREASE IN COVERAGE AND INTENSITY...LARGELY DUE TO THE POCKET OF MOISTURE THAT IS SLIDING OUT OF NORTHEAST MINNESOTA AND ASSOCIATED WITH WEAK SHORTWAVE ENERGY. THIS TREND WILL PROBABLY CONTINUE THROUGH THE NEXT COUPLE HOURS AND HAVE TRENDED POPS UP (FROM CURRENT SCATTERED COVERAGE) THROUGH THE MID MORNING HOURS. STRONGEST SHOWERS WILL LIKELY BE EAST OF MUNISING AND POTENTIALLY FOCUSED IN GOGEBIC/ONTONAGON COUNTIES WITH WINDS TRYING TO BACK SLIGHTLY AHEAD OF THE WEAK LAKE INDUCED SURFACE TROUGH OVER THE WESTERN LAKE EARLY THIS MORNING. HIGH RESOLUTION MODELS PICKING UP ON THIS IDEA IN THEIR PRECIP/REFLECTIVITY FIELDS AND LEADS TO INCREASED CONFIDENCE. ONCE DAYTIME HEATING TAKES HOLD AND POCKET OF DRIER AIR ALONG THE MINNESOTA/CANADA BORDER DROPS OVER THE AREA...THINK THE SHOWERS WILL DIMINISH SOME...ESPECIALLY OVER THE WEST WHERE THE FETCH IS SHORTER. ONE OTHER ITEM FOR THIS AFTERNOON...HELD ONTO SOME POPS OVER THE SOUTH CENTRAL...EVEN THOUGH THAT ISN/T A FAVORABLE LOCATION FOR LAKE EFFECT. FELT HAVING SLIGHT CHANCES WAS REASONABLE WITH THE MOISTURE AVAILABLE AND STEEPENING LAPSE RATES (SFC-850MB VALUES AROUND 9C/KM) WITH THE COLD AIR ALOFT. THIS SHOULD BE ENOUGH FOR SOME CONVECTIVE CLOUD DEVELOPMENT AND MAYBE A FEW SHOWERS WITH THE INCREASING MOISTURE. THAT POCKET OF DRIER AIR WILL DEPART AS A SHORTWAVE DROPS SOUTH FROM ONTARIO THIS AFTERNOON AND EVENING. THIS BRINGS ADDITIONAL LOW-MID LEVEL MOISTURE WITH IT AND WILL AID THE LAKE EFFECT SHOWERS THAT WILL BE ONGOING. IT WILL ALSO BRING ABOUT A SLIGHT WIND SHIFT TO MORE OF A NORTH-NORTHWEST DIRECTION AND PUSH THE ONGOING LAKE EFFECT SHOWERS TO THE WEST. BEST MOISTURE IS OVER THE EASTERN CWA...SO WOULD EXPECT THE STRONGEST SHOWERS THERE WITH THE GREATEST FETCH. MODELS ARE INDICATING THE WINDS SHIFT AIDING A DOMINATE BAND OVER THE EAST DURING THE EVENING (INITIALLY OVER FAR EASTERN LAKE SUPERIOR AND THEN SHIFTING SOUTHWEST TOWARDS GRAND MARAIS) WHICH WILL BE ASSISTED BY MOISTENING OFF LAKE NIPIGON. ONE NEGATIVE WITH THIS SHORTWAVE IS THAT IT DOES PULL SLIGHTLY WARMER 850MB TEMPS OVER THE AREA TONIGHT...RISING SLIGHTLY FROM -8C TODAY TO -6/-7C TONIGHT OVER THE EAST. THIS LEADS TO INCREASING LOW LEVEL TEMPS AND RISING WETBULB ZERO VALUES. 00Z NAM/GFS BUFKIT SOUNDINGS FOR KERY SHOW WETBULB ZERO VALUES RISING TO ALMOST 1.5KFT BY DAYBREAK...WHICH WOULD BE PRETTY MUCH RAIN. ALSO...MUNISING STAYED RIGHT AROUND 41 DEGREES EARLY THIS MORNING UNTIL THE LAND BREEZE KICKED IN AND SHIFTED THE WINDS TO THE SOUTHWEST (TEMP DROPPED TO 36 DEGREES). SINCE THE GRADIENT SHOULD BE TIGHTER TONIGHT...THINK THAT WILL KEEP TEMPS UP RIGHT ALONG THE SHORELINE. THEREFORE...AFTER SNOW DURING THE DAY...HAVE TRENDED TOWARDS A MIX OF RAIN/SNOW EAST OF A LINE FROM MUNISING TO MANISTIQUE. AS FOR SNOW AMOUNTS...THE RAIN/SNOW MIX CREATES UNCERTAINTY ALONG WITH SNOW RATIOS. HAVE KEPT SNOW RATIOS LOWER...TOWARDS 10-1...SINCE THE BEST FORCING CONTINUES TO BE BELOW THE DGZ AND ONLY THE TOP OF THE CLOUD IS WITHIN THE DGZ. AS WAS SEEN TODAY...THERE WILL PROBABLY BE PERIODS OF FLAKES AND ALSO SNOW GRAINS/PELLETS IN THE STRONGER SHOWERS DUE TO THE STRONG LIFT OF SUPER COOLED WATER RUNNING INTO THE SMALLER FLAKES ALOFT. FOR EXAMPLE...TODAY AT OUR OFFICE WE HAD 0.53 INCH OF LIQUID BUT THE SNOWFALL TOTAL WAS 2.2 INCHES. THUS...WONDERING IF THE CURRENT 10-1 FORECAST IS A LITTLE TOO HIGH OVER THE EAST AND MAY BE CLOSER TO A 7/8 TO 1. AS FOR SNOWFALL TOTALS...KEPT AMOUNTS AROUND AN INCH IN THE NW SNOW BELTS FOR TODAY (WITH LOCALIZED HIGHER AMOUNTS NEAR IRONWOOD AND THE PORKIES). THEN FOR TONIGHT...HAVE A GENERAL 1-3IN FOR THE SAME LOCATIONS...BUT LESSER AMOUNTS WHERE THE RAIN/SNOW MIX IS. SOME CONCERN FOR NEAR ADVISORY LEVEL SNOWFALL TONIGHT OVER THE EAST WITH THE DOMINATE BAND. BUT WITH THE UNCERTAINTY ON SNOW TYPE (FLAKE VS PELLET) AND ALSO SOME RAIN MIXING IN NEAR THE SHORELINE...DIDN/T HAVE ENOUGH CONFIDENCE TO ISSUE ONE FOR ALGER COUNTY AREA. .LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 459 PM EDT TUE OCT 22 2013 THE SFC TEMPERATURES THROUGH MONDAY DID NOT CHANGE MUCH AT ALL COMPARED TO THE PREVIOUS FCST...WHICH HELPS KEEP THE WX TYPES SIMILAR. WE WILL BEGIN WEDNESDAY NIGHT WITH THE EXITING SFC LOW OVER N AND CENTRAL QUEBEC...AND HIGH PRESSURE EXTENDING ACROSS MUCH OF WESTERN CANADA INTO THE DAKOTAS. KEPT THE SLIGHT CHANCE OF WATERSPOUTS IN THE FCST FOR FOR WEDNESDAY NIGHT OVER THE E HALF OF LAKE SUPERIOR. STEADY NW FLOW WILL REMAINS ACROSS THE CWA...WITH A GOOD CHANCE OF ACCUMULATING SNOW ACROSS THE NW FAVORED SNOWBELTS. THE DGZ...HOVERING BETWEEN 700 AND 800MB...IS LINED UP WITH WITH THE BEST MOISTURE. MIXING INTO THE 15-20KT LAYER SHOULD ALLOW SNOW SHOWERS TO PUSH FARTHER INLAND. THE SNOWFALL TOTALS OFF OF BUFKIT ARE FINALLY COMING AROUND TO THE 1 TO 3IN NEAR IWD. WILL CONTINUE TO HIT THE NW SNOWBELTS...WITH THE HIGHEST VALUES NEAR IWD...THE HURON MTNS...AND FROM AU TRAIN E TO ERY. THE NW SNOWBELTS WILL SLOWLY GET A BREAK LATE THURSDAY NIGHT INTO FRIDAY...AS THE SFC HIGH DIGS ACROSS THE CENTRAL PLAINS AND EXTENDS A RIDGE ACROSS THE UPPER GREAT LAKES BY FRIDAY AFTERNOON. THE RELATIVELY DRY WEATHER /PARTICULARLY FOR THE KEWEENAW PENINSULA/ WILL BE SHORT LIVED AS A CLIPPER SYSTEM ACROSS MANITOBA FRIDAY AFTERNOON PUSHES ACROSS LAKE SUPERIOR AND UPPER MI FRIDAY NIGHT INTO SATURDAY MORNING. AHEAD OF THE LOW 850MB TEMPS SHOULD RISE INTO THE -2 TO -5C RANGE FRIDAY EVENING. THE COLDER WX WILL BE SLOWER TO PUSH BACK IN ON SATURDAY...WITH SFC TEMPS WARMING INTO THE LOW TO MID 40S FOR MOST AREAS BY LATE MORNING. AS 850MB TEMPS FALL TO NEAR -6C AND THE NW LAKE EFFECT SNOW MACHINE STARTS UP AGAIN...ASSISTED BY YET ANOTHER SHORTWAVE SLIDING IN BEHIND THE MAIN FRIDAY NIGHT TROUGH/SFC LOW. THE TREND HAS BEEN FOR A SLOW AND STEADY WARMUP FOR SUNDAY AND SUNDAY NIGHT...ABOUT 2F WARMER THAN OUR FCST FROM 24HRS AGO. TEMPS AGAIN SHOULD BE NEAR THE SAME VALUES AS SATURDAY...AS ANOTHER SFC RIDGE BUILDS IN FROM THE W. THE WX FOR MONDAY GETS A BIT TRICKIER...AS A STRONGER LOW DEVELOPS ACROSS THE CENTRAL AND S PLAINS STATES. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 136 AM EDT WED OCT 23 2013 ALTHOUGH CONDITIONS WILL REMAIN FAVORABLE FOR LAKE EFFECT -SHSN... DRIER AIR IN THE BOUNDARY LAYER AND VFR CLOUD BASES UPSTREAM OF LAKE SUPERIOR SUGGEST VFR CONDITIONS WILL LIKELY BE THE RULE AT ALL TERMINALS FOR MUCH OF THE OVERNIGHT. HOWEVER...CAN`T RULE OUT BRIEF MVFR IN -SHSN AT KIWD/KCMX. LATE IN THE NIGHT INTO THE MORNING... NOCTURNAL COOLING WILL PROVIDE A MORE FAVORABLE ENVIRONMENT FOR LAKE EFFECT -SHSN...AND WHEN COMBINED WITH SUBTLE SHORTWAVE DROPPING ACROSS THE AREA...EXPECT MVFR CONDITIONS TO BECOME MORE LIKELY AT KIWD/KCMX. NOT OUT OF THE QUESTION THAT THERE COULD BE BRIEF IFR VIS WITH HEAVIER SNOW SHOWERS AS WELL. WNW WIND FLOW WILL NOT BE FAVORABLE FOR MUCH MORE THAN OCNL FLURRIES...IF THAT...AT KSAW. MAY SEE A PERIOD OF MVFR CIGS WITH DAYTIME HEATING AT KSAW. OTHERWISE... ALL TERMINALS SHOULD RETURN TO PREVAILING VFR DURING THE AFTN. MVFR CIGS MAY RETURN THIS EVENING AS MODELS SHOW INCREASING MOISTURE IN THE BOUNDARY LAYER. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 439 AM EDT WED OCT 23 2013 WITH THE UPPER GREAT LAKES BETWEEN A LOW OVER WESTERN QUEBEC AND A HIGH PRESSURE RIDGE STRETCHING FROM THE CANADIAN PRAIRIES AND INTO THE NORTHERN PLAINS...EXPECT PERSISTENT NORTHWEST WINDS OF 15-25KTS THROUGH THURSDAY. THERE COULD BE SOME GUSTS TO 30KTS OVER THE EAST TONIGHT AS THE PRESSURE GRADIENT TIGHTENS SLIGHTLY. WINDS ARE EXPECTED TO DIMINISH AND BACK ON THURSDAY NIGHT AND FRIDAY...AS A HIGH PRESSURE RIDGE MOVES THROUGH THE UPPER GREAT LAKES. A CLIPPER SYSTEM WILL DIVE SOUTHEAST OUT OF CANADA ON FRIDAY NIGHT AND MOVE ACROSS EASTERN LAKE SUPERIOR. THIS WILL ONCE AGAIN SHIFT WINDS BACK TO THE NORTHWEST UP TO 30KTS FOR SATURDAY AND SATURDAY NIGHT...ESPECIALLY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL MOVE BACK INTO THE GREAT LAKES FOR SUNDAY...DECREASING THE WINDS BELOW 20KTS. FINALLY...WILL CONTINUE TO MENTION A SLIGHT CHANCE FOR WATERSPOUTS OVER THE SOUTHEAST PART OF LAKE SUPERIOR FOR THIS AFTERNOON INTO TONIGHT. WATERSPOUT NOMOGRAM INDICATES BORDERLINE POTENTIAL...BUT WITH STRONGER LAKE EFFECT SHOWERS OCCURRING DURING THAT TIME...FELT IT WAS WARRENTED TO KEEP IN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...KF AVIATION...ROLFSON MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
255 AM CDT WED OCT 23 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 255 AM CDT WED OCT 23 2013 CURRENT WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES LOOK QUITE FAMILIAR... GIVEN THAT THE LARGE SCALE PATTERN HASN/T CHANGED MUCH IN THE PAST SEVERAL DAYS. LONGWAVE TROUGH REMAINS OVER THE EASTERN HALF OF THE CONTINENT... WITH A LONGWAVE RIDGE CENTERED ALONG THE WESTERN COAST. WE REMAIN IN PRIMARILY DRY AND COOL NORTHWEST UPPER FLOW. HOWEVER... SOME FLURRIES AND A FEW SNOW SHOWERS ARE EVIDENT IN RADAR IMAGERY AND SURFACE OBS GIVEN SOME WEAK FORCING FROM CHANNELED VORTICITY ADVECTION COMBINED WITH GOOD LAPSE RATES AND JUST ENOUGH MOISTURE TO GET THINGS GOING. THESE CONDITIONS WON/T CHANGE MUCH TODAY... SO THE EASTERN/NORTHERN PORTION OF THE AREA SHOULD CONTINUE TO SEE SOME FLURRIES AND THE ODD SNOW SHOWER THROUGH THE DAY... PERHAPS PICKING UP SOME DURING THE AFTERNOON AS LAPSE RATES STEEPEN IN THE BOUNDARY LAYER. MOSTLY CLOUDY CONDITIONS WILL PERSIST AS WELL... ALTHOUGH SOME BREAKS OF SUNSHINE WILL ONCE AGAIN OCCUR. THE FAR SOUTHWEST PORTION OF THE CWFA WILL HAVE A DEJA VU MOMENT... WITH A VERY SIMILAR SYSTEM TO YESTERDAY PASSING BY TO ITS WEST AND SOUTH THIS MORNING AND EARLY AFTERNOON. GIVEN WHERE THE PCPN IS ALREADY TRYING TO DEVELOP OVER THE DAKOTAS... ITS TRAJECTORY LOOKS TO ONCE AGAIN LARGELY MISS OUR FORECAST AREA... ALTHOUGH SOME FLURRIES OR BRIEF LIGHT SNOW COULD SNEAK ACROSS LOCATIONS SOUTHWEST OF THE MINNESOTA VALLEY. THE HRRR... HOPWRF... AND MPXWRF ALL TELL SIMILAR TALES WITH THIS AREA OF PCPN... KEEPING ANYTHING MEANINGFUL OUT OF OUR AREA. KEPT SOME LOW POPS FOR LIGHT SNOW IN THE FAR SOUTHWEST... WITH A MENTION OF FLURRIES BORDERING ITS NORTHEAST EDGE UP TOWARD THE MINNESOTA RIVER. SOME SURFACE RIDGING LOOKS LIKE IT WILL TRY TO BUILD INTO THE AREA TONIGHT... SO ALLOWED THE ISOLATED SNOW SHOWERS OVER THE NORTHEAST FORECAST AREA TO WIND DOWN IN THE EARLY EVENING. HOWEVER... WITH THE MID-LEVEL COLD POOL STILL OVER THE AREA AND SOME CONTINUED WEAK FORCING... WOULDN/T RULE OUT THE NEED FOR LATER FORECASTS TO THROW A MENTION OF SNOW SHOWERS/FLURRIES BACK INTO THE FORECAST FOR THE ENTIRE NIGHT. REGARDLESS... ANYTHING THAT OCCURS SHOULDN/T BE OF MUCH SIGNIFICANT... WITH ONLY THE HEAVIEST OF SNOW SHOWERS PERHAPS WHITENING THE GROUND. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 255 AM CDT WED OCT 23 2013 THE WESTERN PERIPHERY OF THE EASTERN CONUS MID/UPPER TROUGH HAS ONE LAST DAY OF INFLUENCE OVER THE LOCAL WEATHER ON THURSDAY...WITH STEEPENING LAPSE RATES INDICATING THE POTENTIAL FOR A FEW LIGHT SHOWERS/SPRINKLES...POSSIBLY IN THE FROZEN FORM FOR AREAS NORTH OF INTERSTATE 94 DURING THE MORNING. TEMPS WILL STILL BE ON THE CHILLY SIDE...WITH HIGHS IN THE UPPER 30S TO LOWER 40S EXPECTED...AND LOWS DIPPING INTO THE MID AND UPPER 20S BY DAYBREAK FRIDAY. FRIDAY APPEARS DRY AND A TAD WARMER...AS SOUTHWEST LLVL FLOW DEVELOPS AHEAD OF THE NEXT NORTHERN STREAM WAVE. THE ASSOCIATED TROUGH PASSES ON FRIDAY NIGHT...WITH THE MAIN RESULT BEING A SHIFT TO BRISK NORTHWEST WINDS FOR SATURDAY. WITH THE PRIMARY FORCING RELATED TO THE WAVE PASSING OVER THE GREAT LAKES REGION...NO PRECIPITATION IS EXPECTED FOR THE MAJORITY OF THE AREA...ALTHOUGH A FEW FLURRIES OR LIGHT SNOW/RAIN SHOWERS APPEAR POSSIBLE OVER WEST CENTRAL WI ON FRIDAY NIGHT AND SATURDAY. TEMPERATURES RECOVER A BIT FOR SUNDAY...ALTHOUGH ONLY AREAS ALONG/SOUTH OF THE MN RIVER VALLEY ARE EXPECTED TO ESCAPE THE 40S. DURING THE BEGINNING OF NEXT WEEK...AN UPPER TROUGH IS CARVED OUT FROM THE FOUR CORNERS REGION ACROSS THE CENTRAL/NORTHERN PLAINS. WHILE THERE ARE SOME AMPLITUDE DIFFERENCES BETWEEN THE GFS AND ECMWF...BOTH MODELS INDICATE AT LEAST A SLIGHT POTENTIAL FOR SHOWERS IN THE MONDAY-TUESDAY TIME FRAME. HAVE INCLUDED 20-30 POPS FOR BOTH DAYS. THE PRECIP TYPE WILL BE UNCERTAIN UNTIL THE OTHER LARGER DETAILS ARE WORKED OUT...ALTHOUGH THERMAL PROFILES ARE SUPPORTIVE OF RAIN-SNOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT) ISSUED AT 1124 PM CDT TUE OCT 22 2013 SCATTERED SNOW SHOWERS/FLURRIES CONTINUE ACROSS CENTRAL AND EASTERN MINNESOTA LATE THIS EVENING. VISIBILITIES ARE BEING REDUCED BRIEFLY BUT THERE HAVE BEEN A SLOW WEAKENING TREND WITH THESE CELLS. THEREFORE...NOT PLANNING TO KEEP VCSH IN AT ANY SITES BEYOND 06Z. ADDITIONAL SCATTERED SNOW SHOWERS MAY REDEVELOP BY MIDDAY WEDNESDAY AND CONTINUE INTO THE AFTERNOON...BUT COVERAGE IS UNCERTAIN ENOUGH TO KEEP FROM THE TAFS ATTM. OTHERWISE...CIGS WILL REMAIN BETWEEN 035 AND 070 THROUGH THE PERIOD...ASIDE FROM POTENTIAL SHOW SHOWERS. KMSP...VFR CONDITIONS. -SHSN ACTIVITY IS ON A WANING TREND LATE THIS EVENING WITH ADDITIONAL DEVELOPMENT POSSIBLE AFTER 15Z. WINDS WILL REMAIN NORTHWEST 5-10 KT THROUGH THE PERIOD. /OUTLOOK FOR KMSP/ THU NIGHT...VFR. NW WIND 5-10 KT BCMG W. FRI...VFR. W WIND 5-10 KT BCMG SW 10-15 KT. FRI NIGHT...MVFR CIGS PSBL LATE. SW WIND 10-15 KT BCMG NW. SAT...MVFR CIGS PSBL EARLY. NW WIND 10-15 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...TRH LONG TERM...LS AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
245 AM CDT WED OCT 23 2013 .DISCUSSION... SKIES HAD CLEARED ACROSS MUCH OF EASTERN NEBRASKA AND SOUTHWEST IOWA SINCE 05Z BUT ADDITIONAL CLOUDS OVER THE DAKOTAS ARE EXPECTED TO SPREAD INTO THE AREA PRIOR TO SUNRISE. RADAR ALSO PICKING UP SOME LIGHT PRECIP OVER NORTH CENTRAL SOUTH DAKOTA WITH SHORT RANGE MODELS BRINGING THE PRECIP INTO THE AREA DURING THE MORNING. AS THE CLOUD COVER RETURNS TO BLANKET THE AREA THIS MORNING WE SHOULD SEE TEMPERATURES WARM. RAP FORECAST SOUNDINGS SHOW RAIN TO BE PRIMARY PRECIP TYPE...ALTHOUGH A MIX IS POSSIBLE NORTH OF OMAHA IF ACTUAL TIMING IS FASTER THAN EXPECTED. PERIODS OF SHOWERS THEN EXPECTED THROUGH THE DAY OVER EASTERN PARTS OF THE AREA BUT ENDING NORTH TO SOUTH DURING THE AFTERNOON. REMAINDER OF THE SHORT TERM LOOKS DRY BUT COLD FOR TONIGHT WITH A HARD FREEZE LIKELY ACROSS NORTHERN PARTS OF THE AREA. LIGHT WINDS ON THURSDAY WITH HIGH PRESSURE OVER THE AREA EXPECTED TO HOLD TEMPERATURES IN THE 40S BUT WARMER TEMPERATURES RETURN FRIDAY INTO THE WEEKEND. EXTENDED PERIOD EARLY NEXT WEEK STILL PROBLEMATIC AS OPERATIONAL MODELS DIFFER IN HANDLING OF ENERGY COMING INTO THE GREAT BASIN ON MONDAY AND EVOLUTION OF THE SYSTEM AS IT TRACKS EAST TOWARD THE SOUTHERN PLAINS TUESDAY AND WEDNESDAY. HAVE MAINTAINED CURRENT TRENDS IN THE FORECAST BUT HIGHS ON MONDAY UNCERTAIN DUE TO TIMING AND STRENGTH OF THE FRONT BY THE GFS AND ECMWF. && .AVIATION... 06Z TAFS FOR KOMA...KLNK...KOFK. VFR CONDITIONS SHOULD PREVAIL THE REST OF THE NIGHT...WITH MID LVL CLOUDS INCREASING LATE. AS THE FAST MOVING UPPER LEVEL DISTURBANCE DROPS SOUTHEAST THROUGH THE REGION LATE TONIGHT AND WEDNESDAY... LIGHT MIXED PCPN COULD DEVELOP. MVFR CEILINGS WILL BE MOST LIKELY AT KOFK AND KOMA DURING THE DAYLIGHT HOURS. STRONGEST UPWARD VERTICAL MOTION MOVES OVER THE AREA BETWEEN 15Z AND 23Z. LEFT THE PCPN TYPE AT KOMA RAIN FOR NOW. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ FOBERT/MILLER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1145 PM CDT TUE OCT 22 2013 .AVIATION... 06Z TAFS FOR KOMA...KLNK...KOFK. VFR CONDITIONS SHOULD PREVAIL THE REST OF THE NIGHT...WITH MID LVL CLOUDS INCREASING LATE. AS THE FAST MOVING UPPER LEVEL DISTURBANCE DROPS SOUTHEAST THROUGH THE REGION LATE TONIGHT AND WEDNESDAY... LIGHT MIXED PCPN COULD DEVELOP. MVFR CEILINGS WILL BE MOST LIKELY AT KOFK AND KOMA DURING THE DAYLIGHT HOURS. STRONGEST UPWARD VERTICAL MOTION MOVES OVER THE AREA BETWEEN 15Z AND 23Z. LEFT THE PCPN TYPE AT KOMA RAIN FOR NOW. MILLER && .PREV DISCUSSION... /ISSUED 254 PM CDT TUE OCT 22 2013/ SHORT TERM...TONIGHT THROUGH FRIDAY. THE FIRST CLIPPER SYSTEM WAS MOVING WELL SOUTHEAST OF THE REGION THIS AFTERNOON. MEANWHILE...THE NEXT CLIPPER WAS NOTED COMING OUT OF ALBERTA. 12Z UPPER AIR CHARTS SHOWED ABOUT 20 METER HEIGHT FALLS AT 500 MB...WITH SATURATION AT 700 MB. THIS WILL CONTINUE TO DIVE SOUTHEAST...AND COULD BRING SOME PRECIP TO NORTHEAST NEBRASKA LATE TONIGHT AFTER 09Z...ALTHOUGH LATEST 18Z RUN OF THE RAP AND 12Z ECMWF SUGGEST THAT MEASURABLE PRECIP COULD EVEN HOLD OFF UNTIL AFTER 12Z IN NORTHEAST NEBRASKA. THERMAL PROFILES SUGGEST THIS COULD BE A RAIN/SNOW MIXTURE ALONG THE NE/SD BORDER REGION. CLIPPER THEN CONTINUES TO MOVE EAST SOUTHEAST AND BRINGS PRECIP CHANCES DOWN THE MISSOURI RIVER THROUGH THE MORNING AND INTO THE AFTERNOON...WHERE IT COULD BE A RAIN/SNOW MIXTURE EARLY IN THE MORNING IN NEBRASKA AND NORTHWEST IOWA...BUT AS TEMPS WARM...LIKELY BECOMING ALL RAIN BY 15Z AND BEYOND. NOT EXPECTING ANY ACCUMULATION THOUGH...JUST A RAIN/SNOW MIX POSSIBLE. PRECIP CHANCES WILL CONTINUE TO WIND DOWN THROUGH THE AFTERNOON AND END ALTOGETHER BY WEDNESDAY EVENING. THE NAM ALSO HAD A SLIGHTLY MORE WESTERN TRACK...WHICH SEEMED TO BE TOO FAR WEST GIVEN THE PLACEMENT OF THE DYNAMICS. BEYOND THEN...NO REAL WEATHER CONCERNS AS HIGH PRESSURE SETTLES ACROSS THE PLAINS. THIS WILL RESULT IN A COUPLE OF COLD NIGHTS WEDNESDAY NIGHT...AND EVEN A COUPLE OF DEGREES COLDER THURSDAY THAN WEDNESDAY NIGHT WITH MOSTLY CLEAR SKIES. DAYTIME TEMPS DO REBOUND INTO THE MID/UPPER 50S BY FRIDAY AS SOUTHWEST FLOW RETURNS TO THE REGION. DEWALD LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. EXTENDED MODELS MAINTAIN SIMILAR TRENDS IN BREAKING DOWN THE WESTERN RIDGE OVER THE WEEKEND AS UPPER WAVE DROPS INTO THE NORTHERN ROCKIES WITH DRY AND GENERALLY MILD CONDITIONS THROUGH THIS TIME. PATTERN TURNS MORE ACTIVE EARLY NEXT WEEK. SOME TIMING ISSUES SHOW UP ON MONDAY WITH COLD FRONT THAT MOVES THROUGH THE AREA WITH A BLENDED SOLUTION USED FOR THE FORECAST. ECMWF HOLDS A STRONGER UPPER WAVE FURTHER TO THE NORTHWEST THAN THE MORE PROGRESSIVE AND LESS AMPLIFIED GFS THROUGH TUESDAY. CHANCE POPS WERE CONTINUED FOR MONDAY INTO TUESDAY WITH PRECIP TYPE LESS CERTAIN DEPENDING ON TIMING OF THE COLDER AIR. FOBERT && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
453 AM EDT WED OCT 23 2013 .SYNOPSIS... A SERIES OF COLD FRONTS WILL PUSH ACROSS THE AREA TODAY THROUGH FRIDAY...BRINGING INCREASINGLY COLD AND DRY CONDITIONS. WELL BELOW NORMAL TEMPERATURES ARE EXPECTED LATE WEEK INTO THE WEEKEND...AND THE FIRST FROST OR FREEZE OF THE SEASON COULD OCCUR FRIDAY NIGHT. SLOW WARMING WILL BEGIN SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM WEDNESDAY...LAST OF THE PCPN EAST OF THE I-95 CORRIDOR EXTENDING EAST TO OFF THE CAROLINA COASTS...WILL CONTINUE TO MAKE QUICK PROGRESS TO THE ENE...AND END OVER THE ILM CWA BY DAYBREAK WED. MODEL TIME HEIGHTS FOR VARIOUS LOCATIONS ACROSS THE ILM CWA INDICATE THE DEEPEST MOISTURE WILL HAVE MOVED OFF THE ILM CWA COAST...ALONG WITH DRY AIR ABOVE 8H PROGRESSING ACROSS THE FA. RESIDUAL MOISTURE BELOW 8H ALONG WITH CAA OVERSPREADING THE FA LATER THIS MORNING AND AFTERNOON...COULD RESULT WITH A SCATTERED /BROKEN SC/CU DECK AND THUS WILL NOT GO COMPLETELY CLEAR UNTIL TONIGHT. THE RATHER LARGE AMPLITUDE 5H TROF AXIS...INDIGENOUS TO WINTER SEASON...WILL LIE OVERHEAD COME THIS EVENING AND OVERNIGHT...AND WILL NO LONGER BE ABLE TO TAP GULF OF MEXICO MOISTURE AS WELL AS ATLANTIC OCEAN MOISTURE. THERE ARE CLIPPER TYPE VORTICIES...UPPER S/W TROFS...DIVING SE FROM CANADA THAT WILL AID IN KEEPING THIS WELL CARVED AND LARGE AMPLITUDE UPPER TROF IN TACT FOR THE EASTERN ONE THIRD OF THE U.S. DURING THIS TIME PERIOD...AND EXTENDING INTO THE SHORT TERM PERIOD. MOST TO PASS N OF THE FA...HOWEVER 1 LATE TONIGHT INTO THE SHORT TERM PERIOD...WILL HAVE ENOUGH MOISTURE ACCOMPANYING WITH IT...AND COULD RESULT IN A SCT/BKN MID-LEVEL CLOUD DECK BY DAYBREAK THU. CAA WILL CONTINUE TONIGHT WITH THE 0 DEGREE ISOTHERM ALOFT HAVING DROPPED TO THE 800MB LEVEL COME DAYBREAK THU...AND LIKELY TO FURTHER DROP TO THE 850MB LEVEL IN THE SHORT TERM PERIOD. A DOWNSLOPE TRAJECTORY WITH W-NW FLOW WILL AFFECT THE AREA WITH MAX TEMPS TODAY THAT MAY ACTUALLY BE WARMER ALONG THE IMMEDIATE COAST THEN INLAND LOCATIONS. FOR TODAYS MAX TEMPS...HAVE UTILIZED VARIOUS MODEL MOS GUIDANCE THAT ILLUSTRATE 70-75 INLAND AND MID 70S AT THE COAST. AS FOR TONIGHTS MINS...WILL STAY AT OR SLIGHTLY ABOVE COMPROMISED MODEL MOS GUIDANCE. DO NOT EXPECT A SFC BASED INVERSION AS LOW LEVEL WINDS REMAIN ACTIVE THUS PREVENTING ANY DECOUPLING OR DECENT RADIATIONAL COOLING. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...AS WE APPROACH HALLOWEEN...JACK-O-LANTERNS, GHOSTS, AND WITCHES BEGIN TO CROP UP ACROSS THE AREA...AND IT APPEARS ONE OF THESE WITCHES HAS CAST A SPELL OF WINTER-LIKE WEATHER WHICH WILL IMPACT THE CAROLINAS THROUGH THE SHORT TERM. ABUNDANT SUNSHINE THURSDAY/FRIDAY WILL DO LITTLE TO HELP AFTN TEMP RECOVERY...AND BOTH DAYS WILL BE AROUND 10 DEGREES BELOW CLIMO FOR LATE-OCTOBER. THIS IS DUE TO A COMBINATION OF A LARGE AND STRONG UPPER TROUGH DOMINATING THE EASTERN HALF OF THE COUNTRY...AND A COLD CANADIAN HIGH PRESSURE EXTENDING BENEATH IT. WHILE THURSDAY WILL BE COOL...A SECONDARY AND COLDER SURGE OF AIR /DRY COLD FRONT/ WILL CROSS SOUTH EARLY FRIDAY...MAKING FRIDAY SEVERAL DEGREES COOLER THAN THE ALREADY COOL THURSDAY. IN FACT...LATEST GEFS HAS THE CORE OF THE ABSOLUTE COLDEST 850MB AIR /-3 TO -4 SD`S!/ DRIFTING OVERHEAD FRIDAY...AND FRIDAY NIGHT LOOKS TO BE THE COLDEST NIGHT IN THIS AREA SINCE APRIL 7TH. SO WITH HIGH PRESSURE DOMINATING AND SUNSHINE ABUNDANT...FORECAST BECOMES SOLELY DEPENDENT ON TEMPERATURES. THURSDAY WILL BE COOL...WITH HIGHS RISING INTO THE MID 60S...ABOUT 4-8 DEGREES BELOW NORMAL. EVEN COLDER ON FRIDAY...WHEN HIGHS WILL STRUGGLE TO AROUND 60...AND EXPECT MANY PLACES IN THE NC ZONES WILL STAY IN THE UPPER 50S...AVERAGE HIGHS FOR DECEMBER. LOWS THURSDAY NIGHT WILL DROP TO A DEGREE OR TWO ABOVE 40...BEFORE PLUMMETING FRIDAY NIGHT INTO THE MID...OR EVEN LOW 30S! THIS PROMOTES THE POTENTIAL FOR FROST ACROSS THE AREA FRIDAY NIGHT...AND WITH WINDS AT THE TOP OF THE RESIDUAL LAYER FRIDAY NIGHT ONLY FORECAST TO BE 2-5 KTS...IDEAL RADIATIONAL COOLING MAY ALLOW THE COOLER SPOTS TO DROP TO FREEZING. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...PERIOD STARTS WITH ONE MORE WELL BELOW NORMAL DAY AS 850MB TEMPS AROUND 0C COMBINE WITH CANADIAN HIGH PRESSURE AND 5H TROUGH TO KEEP TEMPS FROM RISING MUCH PAST 60. BEYOND SATURDAY...SURFACE HIGH BEGINS TO MIGRATE TO THE NORTHEAST ALLOWING FOR SLOW WARMING ON RETURN FLOW...AND 1000-500MB THICKNESSES SLOWLY INCREASE DOWNSTREAM OF A 5H LOW DROPPING ACROSS THE MTN WEST. THE CENTER OF THE SURFACE HIGH WILL MOVE INTO NEW ENGLAND...CAUSING DEVELOPING NE FLOW...AND THIS WILL LIMIT SIGNIFICANT WARMING. STILL...TEMPS WILL RECOVER TO SEASONABLE LEVELS BY EARLY NEXT WEEK. NO PRECIP EXPECTED THROUGH THE PERIOD. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...MVFR CONDITIONS WILL RULE THE PRE-DAWN WED HOURS DUE TO REDUCED VSBY FROM -SHRA AND CLOUD DECKS BELOW 3K FT. IFR CONDITIONS REMAIN POSSIBLE AFTER THE PCPN CEASES...WITH 2SM VSBY FROM FOG AND/OR A BRIEF LOW CLOUD DECK BETWEEN 1K AND 2K FEET. COLD FRONTAL PASSAGE WILL OCCUR FROM WEST TO EAST EARLY THIS AM. BY DAYBREAK WED...THE COLD FRONT SHOULD BE OFF THE CAROLINA COASTS...AS ILLUSTRATING BY VARIOUS MODELS SFC STREAMLINE FCSTS. VARIOUS MODEL TIME HEIGHT SECTIONS ILLUSTRATE THE DRIER AIR THROUGHOUT THE ATM COLUMN WILL OVERSPREAD THE FA LATER THIS MORNING...AND ESPECIALLY THIS AFTN AND EVENING. THE DOWNSLOPE TRAJECTORY IN THE WIND FIELDS BOTH SFC AND ALOFT...WILL ALSO PROVIDE A SCOURING OF ANY RESIDUAL MOISTURE. WINDS WILL ALSO BECOME QUITE ACTIVE SFC-ALOFT. THE CAA COMBINING WITH A TIGHTENED SFC PG...WILL RESULT WITH W TO NW WINDS AT 15 TO 25 KT. THE WIND INSTRUMENTATION AT THE CRE TERMINAL IS SOMEWHAT PROTECTED DURING W TO NW WIND EVENTS...AND AS A RESULT WILL CHOP OFF 5+ KT OFF CRE TAF DURING TODAY. EXTENDED OUTLOOK...EXPECT VFR THROUGH THE EXTENDED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 330 AM WEDNESDAY...SCA HAS BEEN RAISED FOR ALL ZONES MAINLY DUE TO WIND SPEEDS OF 15-25 KT WITH HIER GUSTS. LIMITED FETCH WILL KEEP 6 FOOT OR HIER SEAS RIGHT AT THE CUSP OR BOUNDARY BETWEEN THE COASTAL AND OFFSHORE WATERS. SFC COLD FRONT TO PUSH EAST...OFF THE MAINLAND AND ACROSS THE WATERS AND OFFSHORE BY DAYBREAK WED. SW-W 10-15 KT WIND WILL VEER TO W TO WNW 10 TO 20 KT WITH HIER GUSTS THIS MORNING. FOR THIS AFTERNOON AND EVENING...A TIGHTENING SFC PG COMBINED WITH CAA WILL RESULT WITH WNW-NW INCREASING TO 15 TO 25 KT WITH SOME HIER GUSTS. LATEST HRRR HIGHLIGHTS THIS WIND FIELD OVERSPREADING THE WATERS INTO TONIGHT. SIGNIFICANT SEAS WILL BUILD TO 3 TO 6 FT...WITH THE 6 FOOTERS PRIMARILY ACROSS THE OUTER WATERS OFF CAPE FEAR. AVERAGE PERIODS WILL RUN 4 TO 5 SECONDS...WITH DOMINATE PERIODS AT 6 TO 7 SECONDS. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...NW WINDS OF 10-15 KTS TO START THURSDAY WILL EASE THROUGH THE DAY AS COOL HIGH PRESSURE BUILDS ACROSS THE WATERS...WEAKENING THE PRESSURE GRADIENT. THE LIGHTER WINDS WILL BE SHORT-LIVED HOWEVER...THANKS TO A DRY COLD FRONT WHICH WILL CROSS THE WATERS EARLY FRIDAY. THIS WILL CAUSE A RENEWED SURGE OF N/NW WINDS ALL OF FRIDAY...INCREASING TO 15-20 KTS THROUGH THE END OF THE PERIOD. THE SEA STATE WILL BE ENTIRELY WIND-WAVE DOMINATED...WITH A 4-5 SEC NORTHERLY WIND CHOP THE MOST SIGNIFICANT WAVE GROUP. WAVE HEIGHTS WILL BE LIMITED THANKS TO THE OFFSHORE WIND COMPONENT...REACHING 1-3 FT THROUGH THE PERIOD. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...HIGH PRESSURE MOVING NEAR THE WATERS THROUGH THE PERIOD WILL KEEP A RELATIVELY WEAK GRADIENT...THUS KEEPING WINDS LIGHT. ALTHOUGH WIND DIRECTION WILL SHIFT FROM NORTH EARLY SATURDAY...BACK TO WEST...AND EVENTUALLY RETURN TO THE NE BY LATE SUNDAY...SPEEDS WILL BE AROUND 10 KTS THROUGH THE EXTENDED. SEAS WILL BE ONLY 1-2 FT THANKS TO THE LIGHT WINDS AND LACK OF ANY SIGNIFICANT SWELL...WITH A VARIABLE WAVE DIRECTION FOLLOWING THE WIND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO MIDNIGHT EDT TONIGHT FOR AMZ250-252-254-256. && $$ SYNOPSIS...JDW NEAR TERM...DCH SHORT TERM...JDW LONG TERM...JDW AVIATION...DCH MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
154 AM EDT WED OCT 23 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL CROSS THE OHIO VALLEY TONIGHT...BRINGING RAIN TO THE REGION...MIXING WITH SNOW IN SOME LOCATIONS DURING THE EARLY MORNING HOURS. MUCH COLDER AIR WILL MOVE IN ON WEDNESDAY...WITH BELOW NORMAL TEMPERATURES AND OCCASIONAL LIGHT RAIN OR SNOW SHOWERS EXPECTED THROUGH THE START OF THE WEEKEND. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... TEMPERATURES HAVE DROPPED AND DEW POINTS HAVE RISEN A BIT MORE RAPIDLY ACROSS THE NORTHWESTERN CWA THAN ORIGINALLY FORECAST. ALREADY TEMPS ARE IN THE MID 30S THERE. CURRENT RADAR MOSAIC SHOWS BROKEN BANDS OF LIGHT RAIN ACROSS THE REGION. EXPECTING THE SLIGHTLY MORE INTENSE PRECIP CURRENTLY OVER INDIANA TO GRADUALLY FILL IN A LITTLE MORE AS LOW PRESSURE /ABOUT TO ENTER SW INDIANA/ SLIDES INTO THE LOWER OHIO VALLEY AND SKIRTS THE SOUTHERN CWA. THE LATEST HRRR AND RAP13 RUNS BOTH HAVE A PRETTY GOOD HANDLE ON CURRENT PRECIPITATION TRENDS AND BOTH SHOW THE QPF FILLING IN A BIT MORE AS THE PRECIP MOVES ACROSS THE CWA EARLY WEDNESDAY MORNING. STILL EXPECTING A RAIN/SNOW MIX TO DEVELOP OVER THE NEXT SEVERAL HOURS AS TEMPS CONTINUE TO DROP OVERNIGHT. PREVIOUS DISCUSSION FOLLOWS... A COMPLICATED FORECAST SCENARIO HAS SET UP FOR TONIGHT...WITH SEVERAL CHALLENGES INVOLVING TIMING...TEMPERATURE...AND PRECIPITATION TYPE. THE OVERALL SCENARIO IS IN GOOD AGREEMENT (AS IT SHOULD BE WITHIN A DAY)...BUT UNFORTUNATELY THERE ARE A FEW KEY DIFFERENCES IN THE DETAILS. THE FIRST KEY TO THE FORECAST IS TIMING. AS A GENERAL RULE FOR THE MODEL RUNS TODAY...THE HIGHER-RESOLUTION THE MODEL...THE SLOWER THE PROGRESSION OF THE WEATHER SYSTEM. THE GFS AND ECMWF ARE ON THE FAST SIDE OF THE SOLUTIONS...ENDING THE MAJORITY OF PRECIPITATION IN THE ILN CWA BY 12Z. THE ARW/NMM RUNS AND NAM12 ARE SLOWER...WITH THE BULK OF THE PRECIPITATION STILL IMPACTING THE AREA AT DAYBREAK. IN REALITY...THE CURRENT POSITION OF THE SURFACE LOW INDICATES A SCENARIO SOMEWHERE BETWEEN THE TWO EXTREMES. JUST NORTH OF THE TRACK OF THE LOW...AN AXIS OF 850MB CONVERGENCE WILL COMBINE WITH LIFT FROM THE SHORTWAVE TO GENERATE AN AREA OF STEADY PRECIPITATION. THE GENERAL TRACK OF THE BEST FORCING IS IN GOOD AGREEMENT...SANS THE WRF-ARW (A LITTLE FURTHER SOUTH) AND THE RAP (A LITTLE FURTHER NORTH). QPF AMOUNTS OF A FEW TENTHS OF AN INCH LOOK POSSIBLE ALONG THIS AXIS...STRETCHING FROM CENTRAL INDIANA THROUGH SOUTHEASTERN OHIO. CATEGORICAL POPS WERE REQUIRED THROUGH THIS AREA...WITH ONLY THE SLIGHT TIMING CONCERNS PREVENTING 100-POPS AND EVEN GREATER DETAIL FROM BEING USED. BETWEEN THE DIURNAL CYCLE AND THE EXTRA PUSH OF COLD AIR BEHIND THE SURFACE LOW...TEMPERATURES ARE EXPECTED TO FALL INTO THE LOWER-TO-MID 30S (NORTHWEST CWA) TO AROUND 40 (SOUTHERN CWA) TONIGHT. IT HAS BECOME EVIDENT THAT THESE TEMPERATURES WILL BE COLD ENOUGH TO SUPPORT SNOW MIXING IN WITH RAIN...WITH (FOR CERTAIN LOCATIONS) SNOW LIKELY EVEN BECOMING THE DOMINANT PRECIPITATION TYPE FOR A COUPLE HOURS NEAR DAYBREAK. THE CRUX OF THIS FORECAST IS THE TIMING AND PLACEMENT OF THESE TEMPERATURES...JUXTAPOSED WITH THE AXIS OF HEAVIEST PRECIPITATION. MUCH OF THE NORTHERN TWO-THIRDS OF THE CWA ARE LIKELY TO EXPERIENCE A BIT OF WET SNOW MIXING WITH RAIN. HOWEVER...THERE WILL BE A WINDOW FOR A COUPLE HOURS IN WHICH AN AXIS FROM RICHMOND IN TO XENIA OH APPEARS TO BE COLD ENOUGH TO SUPPORT SNOW AS THE PRIMARY PRECIPITATION TYPE...WHILE MODERATE PRECIPITATION INTENSITY IS STILL OCCURRING. THIS IS WHERE SOME OF THE SUBTLE DIFFERENCES IN TEMPERATURE FORECASTS CAN HAVE A BIG IMPACT. THE HIGHER-RESOLUTION MODELS ALLOW FOR AN AREA OF DYNAMIC COOLING OCCURRING WITH THE PRECIPITATION...A LEGITIMATE POSSIBILITY (ONE UNTOUCHED BY THE COARSER MODELS) THAT WOULD INCREASE CHANCES FOR SNOW. GROUND TEMPS ARE QUITE WARM (MID TO UPPER 40S) AND IT IS VERY UNLIKELY THAT ANY IMPACTS WILL BE FELT ON PAVEMENT. HOWEVER...WET ACCUMULATIONS ON GRASS OR RAISED SURFACES WILL BE POSSIBLE IN THIS CORRIDOR...AND THE FORECAST GRIDS WILL ALLOW FOR SEVERAL TENTHS OF AN INCH IN THE AFOREMENTIONED LOCATIONS. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/... TEMPERATURES WILL UP WARM ENOUGH TO FORCE ALL PRECIPITATION TO RAIN BY MID-MORNING ON WEDNESDAY. THE WEATHER PATTERN FOR THE NEXT TWO DAYS WILL LACK ANY SIGNIFICANT SMALL-SCALE FEATURES...WITH THE BROAD TROUGH OVER THE EASTERN HALF OF THE CONTINENT HOLDING GENERAL CONTROL OVER THE WEATHER PATTERN THROUGH THE WEEKEND. COLD TEMPERATURES WILL BE THE MAIN STORY FOR THE REST OF THE WEEK...WITH 850MB TEMPS AS LOW AS -4 TO -7 DEGREES CELSIUS. THE MAX TEMPS IN THE MID TO UPPER 40S WILL BE A SOLID 15 DEGREES BELOW NORMAL. ANY PRECIPITATION DURING THIS TIME FRAME IS EXPECTED TO BE LIGHT AND SHOWERY...WITH RAIN BEING THE DOMINANT PRECIPITATION TYPE...BUT SOME LIGHT SNOW MIXING IN DURING THE OVERNIGHT HOURS. THE COLD AIR ALOFT MAKES FOR A RATHER UNCERTAIN CLOUD FORECAST...WITH A DIVERSE ARRAY OF SPLOTCHY RH FIELDS BETWEEN DIFFERENT MODEL RUNS. THIS WILL HAVE AN OBVIOUS IMPACT ON TEMPERATURES...MOST IMPORTANTLY ON THE POTENTIAL FOR FREEZING CONDITIONS ON WEDNESDAY NIGHT AND THURSDAY NIGHT. THE AIR MASS WILL BE EASILY COLD ENOUGH TO SUPPORT THE FIRST WIDESPREAD FREEZE OF THE SEASON FOR THE ILN CWA...BUT THE CLOUD FORECAST LEAVES THIS QUESTION UNANSWERED. THERE WAS ENOUGH CONFIDENCE FOR A THIRD-PERIOD FREEZE WATCH...WHICH HAS BEEN ISSUED FOR MOST OF THE CWA FOR WEDNESDAY NIGHT INTO THURSDAY MORNING. RAW MODEL TEMPS (WHICH DIP INTO THE 20S IN A FEW PLACES ON WEDNESDAY NIGHT) ARE ACTUALLY EVEN MORE FAVORABLE FOR THURSDAY NIGHT...SO ADDITIONAL HEADLINES LOOK FAIRLY LIKELY IN THE FUTURE. && .LONG TERM /FRIDAY THROUGH TUESDAY/... UPPER TROUGH WILL MOVE EAST OF THE FA THROUGH THE DAY ON FRIDAY. WINDS OFF OF THE LAKE WILL ALLOW FOR SOME CLOUD COVER ACROSS NORTHERN PORTIONS OF THE FA ON FRIDAY. ELSEWHERE ACROSS THE FA MOSTLY CLEAR CONDITIONS WILL BE PRESENT AND THEREFORE WIDESPREAD FROST CAN BE EXPECTED FRIDAY MORNING. TEMPERATURES WILL ONLY RISE INTO THE 40S ON FRIDAY WITH COOL AIR STILL IN PLACE. PRECIPITATION ASSOCIATED WITH AN UPPER LEVEL DISTURBANCE WILL STAY NORTH OF THE FA SATURDAY INTO SATURDAY NIGHT. WINDS WILL PICK UP HOWEVER DURING THE DAY ON SATURDAY WITH WIND GUSTS OF 20 TO 30 MPH POSSIBLE. THESE SOUTHERLY WINDS WILL ALLOW TEMPERATURES TO BE A LITTLE WARMER ON SATURDAY. HIGH TEMPERATURES ON SATURDAY WILL BE IN THE 50S. THESE VALUES ARE STILL BELOW NORMAL FOR THIS TIME OF YEAR. WITH THE PASSAGE OF THE UPPER LEVEL DISTURBANCE COOLER AIR WILL WORK INTO THE REGION FOR SUNDAY. THIS WILL LIMIT HIGH TEMPERATURES ON SUNDAY TO THE UPPER 40S TO LOW 50S ACROSS MOST LOCATIONS. WARMER AIR WILL WORK INTO THE REGION FOR MONDAY AND TUESDAY WITH SOUTHERLY FLOW DEVELOPING. A LOW PRESSURE SYSTEM WILL APPROACH THE AREA ON TUESDAY AND RAIN SHOWERS ASSOCIATED WITH THIS SYSTEM WILL BEGIN TO WORK INTO THE REGION ON TUESDAY. RAIN SHOWERS ARE EXPECTED TO OVERSPREAD THE ENTIRE AREA TUESDAY NIGHT. THERE ARE STILL QUITE A FEW MODEL DISCREPANCIES ON THE EXACT TIMING AND STRENGTH OF THIS SYSTEM HOWEVER MODELS ARE IN AGREEMENT WITH BRINGING PRECIPITATION INTO THE FA. DUE TO THIS HAVE INCREASED PRECIPITATION CHANCES ACROSS THE AREA LATE TUESDAY INTO TUESDAY NIGHT. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... SURFACE LOW MOVING ACROSS WEST CENTRAL INDIANA EARLY THIS MORNING IS FORECAST TO SLIDE EAST SOUTHEAST ACROSS OUR AREA THROUGH LATE MORNING. THE MOST WIDESPREAD PCPN IS LOCATED NORTH AND EAST OF THE LOW WITH A BIT OF A DRY SLOT WORKING UP INTO SOUTHWEST INDIANA. CIGS ARE GENERALLY VFR ACROSS OUR AREA ATTM BUT THEY SHOULD DROP DOWN INTO MVFR WITH THE APPROACH OF THE LOW AND ONSET OF MORE STEADY PCPN. ALONG AND NORTH OF THE LOW TRACK...CIGS WILL LIKELY CONTINUE TO FALL INTO IFR CATEGORY. EXPECT PTYPE TO REMAIN MAINLY RAIN...ALTHOUGH BOUNDARY LAYER ALONG AND NORTH OF THE LOW TRACK MAY COOL OFF ENOUGH TO SUPPORT A COUPLE HOUR PERIOD OF SNOW OR AT LEAST A RAIN/SNOW MIX. THIS IS MOST LIKELY TO AFFECT KDAY AND KILN AS WE GET CLOSER TO DAYBREAK. PCPN WILL TAPER OFF FROM WEST TO EAST THROUGH MID TO LATE MORNING AS THE LOW PUSHES OFF TO THE EAST. THIS WILL ALSO ALLOW FOR A GRADUAL IMPROVEMENT IN CIGS FROM LATE MORNING INTO EARLY AFTERNOON. THE UPPER LEVEL TROUGH WILL REMAIN IN PLACE ACROSS THE AREA INTO THURSDAY. WITH SOME WEAK ENERGY ROTATING THROUGH THE TROUGH...TOUGH TO RULE OUT AN ADDITIONAL ISOLATED SHOWER...BUT CHANCE SHOULD BE LOW ENOUGH TO LEAVE MENTION OUT OF THE TAFS. OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR OHZ026-034-035-042>046-051>056-060>065-070>074-080-082- 088. KY...NONE. IN...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR INZ050-058-059-066. && $$ SYNOPSIS...HATZOS NEAR TERM...HATZOS/KURZ SHORT TERM...HATZOS LONG TERM...NOVAK AVIATION...JGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
156 AM EDT WED OCT 23 2013 .SYNOPSIS... A COLD FRONT WILL GRADUALLY MOVE OFFSHORE TONIGHT WITH A COLD CANADIAN AIR MASS GRADUALLY SETTLING OVER THE REGION ON WEDNESDAY. THIS AIRMASS IS EXPECTED TO LINGER WELL INTO THE WEEKEND AND BRING THE COLDEST TEMPERATURES SO FAR THIS SEASON. && .NEAR TERM /THROUGH TODAY/... AS OF 150 AM EDT WEDNESDAY UPDATE...WIDESPREAD LOW STRATUS CLOUDS WITH SOME FOG HAVE DEVELOPED OVER THE UPSTATE OF SC AND PORTIONS OF NC PIEDMONT OVERNIGHT. HENCE...HAVE MADE UPDATES TO THE SKY COVER/WX GRIDS TO ACCOUNT FOR THE LATEST OBS TREND. OTHERWISE...FORECAST IS ON TRACK. AS OF 1015 PM...A POTENT UPR SHORTWAVE CONTINUES TO DIVE INTO THE BASE OF A POSITIVELY-TILTED TROF AXIS INVOF THE MID MS VLY THIS EVENING. SO FAR...THE FRONT SIDE OF THE SYSTEM HAS SLOWED/STALLED...WITH MOISTURE AND LIFT CONTINUING TO STREAM FROM SW TO NE IN THE MID LVLS. A FEW WEAK RETURNS OCCASIONALLY SHOWING UP ON RADAR...PRIMARILY IN THE NC PIEDMONT AND NRN MTNS. SO WILL CONTINUE TO KEEP A SLGT CHC TO LOW-END CHC POP FOR A FEW MORE HOURS. ALSO...WITH A COLD FRONT STALLED ALONG THE BLUE RIDGE...THE DEWPTS ARE RUNNING QUITE A BIT HIGHER THAN TRENDS IN THE GRIDS. SO THOSE WERE ADJUSTED INTO THE OVERNIGHT. THIS MAY RESULT IN A BIT MORE FOG OUT THERE THAN PREVIOUSLY THOUGHT...BUT NO WIDESPREAD DENSE FOG IS EXPECTED. MEANWHILE...SOME SHOWERS AND A STRONGER FRONT PUSH INTO THE OH VLY ATTM ASSOCIATED WITH THE POTENT SHORTWAVE...ACCOMPANIED BY BATCH OF GENERALLY LGT SHWRS. THIS MOISTURE IS EXPECTED TO ARRIVE AT THE TN/NC BORDER AROUND DAYBREAK...SO POPS THERE WILL CONTINUE TO BE CARRIED. THE COLD ADVECTION DOESN/T REALLY GET GOING UNTIL MID WED MORNING...SO MIN TEMPS SHUD BE GENERALLY IN THE 40S TO LWR 50S...WITH 30S ABOVE ABOUT 5000 FT. PERHAPS MT MITCHELL COULD SEE A SNOW FLAKE OR TWO...BUT OTHERWISE THE SHWRS SHUD BE RAIN. THE NRN STREAM WAVE WILL PUSH A STRONGER FRONT ACROSS THE REGION A LITTLE AFTER 12 UTC ON WED. STRONG COLD ADVECTION AND 35 KT NW FLOW AT 850 MB WILL RESULT IN SHOWERS ALONG THE TN LINE. FREEZING LEVELS WILL BE HIGH THROUGH THE DAY...AND ANY SNOW SHOWER ACTIVITY SHOULD BE CONFINED TO ELEVATIONS ABOVE 5000 FEET. NOT EXPECTING WINDS TO REACH LAKE WIND CRITERIA OVER THE MOUNTAINS...THOUGH THE NRN MTNS COULD BE CLOSE. && .SHORT TERM /TONIGHT THROUGH FRIDAY/... AS OF 2 PM EDT TUESDAY...THE SHORT TERM FCST PICKS UP AT 00Z ON THURSDAY WITH THE BROAD UPPER TROF AXIS JUST TO OUR NORTH AND UPPER RIDGING MAINTAINING ITSELF OVER THE FAR WESTERN CONUS. THE UPPER RIDGE WILL GRADUALLY SHIFT EASTWARD ON FRIDAY AND START TO DEAMPLIFY AS IT MOVES OFFSHORE AND HEIGHTS RISE OVER THE CAROLINAS. ON THURSDAY...COOLER AND DRIER SFC HIGH PRESSURE WILL BE PUSHING INTO THE CWFA AS WE BEGIN THE PERIOD. NWLY TO WLY LOW LVL WINDS WILL PERSIST THROUGHOUT THE DAY WITH MORE OF A WLY COMPONENT EXPECTED DURING THE LATER HALF OF THE DAY/EVENING. MOST OF THE MODEL GUIDANCE INDICATES THAT A LIMITED PLUME OF DEEPER LAYER MOISTURE WILL MOVE ACROSS THE CWFA DURING THE DAY...BUT WILL LIKELY NOT AMOUNT TO MUCH IF ANY PRECIP. THE BEST CHANCES WILL BE CONFINED TO THE NORTHERN MTS AND ALONG THE TENN/NC BORDER. THE MAIN CONCERN WILL BE THE POTENTIAL FOR A WIDESPREAD FREEZE ACROSS MUCH OF THE HIGHER TERRAIN EARLY THURS WITH SOME AREAS OF FROST POSSIBLE OVER THE NC FOOTHILLS. ON FRIDAY...THE CANADIAN HIGH REINFORCES ITSELF AS IT SLIDES DOWN FROM THE NW AND SETTLES JUST TO OUR WEST AS THE PERIOD ENDS 00Z SAT. THE ATMOSPHERE IS EXPECTED TO BECOME MORE DRY AS THE DAY PROGRESSES AND THE CENTER OF THE HIGH APPROACHES THE AREA. WITH THAT SAID...I DO NOT CARRY ANY SIG POPS AFTER ABOUT 12Z FRI WITH NO QPF BEYOND THAT MORNING. HIGH TEMPS ARE EXPECTED TO REMAIN ABOUT A CATEGORY BELOW THURS MAXES AND THUS...WELL BELOW CLIMATOLOGY FOR LATE OCTOBER. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... AS OF 200 PM EDT TUESDAY...THE GLOBAL MODELS CONTINUE TO SHOW GOOD GOOD AGREEMENT WITH THE OVERALL SYNOPTIC PATTERN THIS WEEKEND INTO NEXT WEEK. THE DEEP UPPER TROUGH THAT USHERED IN THE UNSEASONABLY COLD WEATHER INTO THE REGION WILL CONTINUE TO MOVE OFF TO THE E-NE THROUGH THE WEEKEND. IN ITS WAKE A A ZONAL WESTERLY UPPER FLOW IS EXPECTED ON SUN AND THEN BECOME SW THE FIRST OF NEXT WEEK AS A DEEP UPPER TROUGH IS CARVED OUT OVER THE ROCKIES...AND WEAK SOUTHERN STREAM SHORT WAVE RIPPLES THROUGH THE DEEP SOUTH. AT THE SURFACE...STRONG CANADIAN HIGH PRESSURE WILL SETTLE OVER THE REGION FRIDAY NIGHT AND BECOME SUPPRESSED TO THE SOUTH OF THE AREA ON SUNDAY AS A WEAK...DRY COLD FRONT MOVES THROUGH THE AREA. HIGH PRESSURE IN THE WAKE OF THE FRONT WILL BUILD OVER THE REGION FROM THE NORTH AND REMAIN RIDGED ACROSS THE AREA THROUGH TUE. THE COLDEST TEMPS OF THIS COLD SPELL WILL OCCUR FRI NIGHT AS THE THE CANADIAN HIGH SETTLES OVER THE REGION ALLOWING FOR IDEAL RADIATIONAL COOLING CONDTIONS. LOWS WILL BE FROM AROUND 30 TO THE LOWER 30S OUTSIDE THE MOUNTAINS....WITH MID TO UPPER 20S MOUNTAIN AREAS. TEMPS WILL MODERATE AFTER THAT AND REACH NEAR NORMAL VALUES ON SUN AND THEN A LITTLE ABOVE NORMAL THE FIRST OF NEXT WEEK. IT SHOULD BE A DRY PERIOD AS HIGH PRESSURE WILL PREDOMINATE. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... AT KCLT...SPRINKLES ARE DISSIPATING AND SHIFTING EAST...SO HAVE LEFT OUT ANY PRECIP MENTION FOR THE START OF THE 00Z TAFS. MID CLOUDS WILL LINGER THRU THE EVENING...WITH ADDITIONAL SPRINKLES POSSIBLE...BUT TOO LOW TO MENTION ANYTHING IN THE TAF. SOME OF THE HIGH RES GUIDANCE...NAMELY THE HRRR AND NARRE-TL...HINT AT SOME PATCHY IFR OR MVFR STRATUS DEVELOPMENT FROM THE MIDLANDS UP THRU PORTIONS OF THE NC PIEDMONT LATER THIS EVENING...THEN DISSIPATING BEFORE DAYBREAK...AS DRY AIR STARTS TO FILTER IN. CONFIDENCE IS JUST TOO LOW TO EVEN HINT AT IT AT THIS TIME. OTHERWISE...VFR THRU THE NIGHT. BY MIDDAY WEDNESDAY...WNW WINDS WILL INCREASE AND BECOME GUSTY. PROBABLY WILL BE PESKY CROSS WIND THRU THE AFTN...WITH GUSTS IN THE 20-25 KT RANGE FREQUENTLY. SKIES SHUD BE MOSTLY CLEAR THO. ELSEWHERE...MID CLOUDS CONTINUE TO LINGER THRU THE EVENING HOURS...WITH A FEW PATCHY SPRINKLES POSSIBLE IN SPOTS. BUT LOW ENUF CHC AND COVERAGE TO LEAVE OUT OF THE TAFS. GUIDANCE AGREES ON ONLY KHKY HAVING MUCH CHC OF ANY VSBY OR CIG RESTRICTIONS...WITH LAKE FOG POSSIBLE OUT OF THE WNW. WINDS WILL INCREASE AND BECOME GUSTY OUT OF THE WEST OR NW BY MIDDAY AT ALL SITES...THEN BEGIN TO SUBSIDE TOWARD 00Z THURSDAY. OUTLOOK...ANOTHER COLD FRONT WILL PASS THROUGH THE AREA THURSDAY. HOWEVER...ANY RESTRICTIONS WILL BE CONFINED TO THE HIGH TERRAIN OF THE NC MOUNTAINS. CONFIDENCE TABLE... 06-12Z 12-18Z 18-24Z 00-06Z KCLT HIGH 88% HIGH 100% HIGH 100% HIGH 100% KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100% KHKY HIGH 95% HIGH 91% HIGH 100% HIGH 100% KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100% KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100% THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE) WWW.WEATHER.GOV/GSP/AVIATION_TABLES && .FIRE WEATHER... AS OF 225 PM EDT TUESDAY...MUCH DRIER AIR WILL ENTER THE WESTERN CAROLINAS AND NORTHEAST GEORGIA BEHIND A COLD FRONT WEDNESDAY AFTERNOON. HUMIDITY VALUES ARE EXPECTED TO FALL BETWEEN 25-30 PERCENT OVER THE UPSTATE AND NE GA...WITH SLIGHTLY HIGHER VALUES OVER WESTERN NORTH CAROLINA. AFTERNOON FUEL MOISTURE VALUES HAVE BEEN STEADILY DECREASING OVER THE PAST FEW DAYS. BY MID AFTERNOON WIND GUSTS WILL INCREASE TO 25 MPH. ALL OF THIS WILL LEAD TO A BRIEF PERIOD OF HEIGHTENED FIRE DANGER WEDNESDAY AFTERNOON. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR NCZ033-048>053-058-059-062>065-501-503-505-507-509. SC...NONE. && $$ SYNOPSIS...JPT NEAR TERM...ARK/JOH SHORT TERM...JPT LONG TERM...LG AVIATION...ARK FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1219 AM CDT WED OCT 23 2013 .UPDATE...FOR 06Z TAFS... && .AVIATION... FRONTAL BOUNDARY CURRENTLY PUSHING THROUGH MIDDLE TN...JUST WEST OF NASHVILLE. LIGHT SHOWERS WILL LIKELY IMPACT BNA BEFORE 06Z AND QUICKLY EXIT THE AREA. WINDS MAY GUST TO 20KT AT TIMES AS THE BOUNDARY PASSES BNA AND THEN CSV AROUND 07Z TO 08Z. SCT TO BKN MVFR CIGS EXPECTED TO LINGER THROUGHOUT THE NIGHT AT CKV AND BNA. LIGHT FOG AT CSV IS EXPECTED TO DISSIPATE AS THE FRONT APPROACHES AND WINDS PICK UP...HOWEVER BKN CIGS AROUND 3000FT WILL LIKELY LINGER THROUGH EARLY MORNING. CLOUDS SHOULD SCATTER OUT DURING THE DAY ON WEDNESDAY WITH STEADY NW WINDS BETWEEN 5 TO 10 KNOTS. && .PREV DISCUSSION... /ISSUED 825 PM CDT TUE OCT 22 2013/ UPDATE... COLD FRONT AND ASSOCIATED LINE OF SHOWERS CURRENTLY RACING SOUTHEAST ACROSS SOUTHERN ILLINOIS AND WESTERN KENTUCKY PER RADAR IMAGERY. LATEST HRRR AND 12KM WRF MODELS BOTH BRING LINE OF SHOWERS INTO THE CWA IN A FEW HOURS BUT WEAKEN THE LINE AS IT MOVES THROUGH THE MID STATE. NEVERTHELESS...BASED ON RADAR TRENDS WILL HAVE TO BUMP UP POPS TO SLIGHT/LOW CHANCE OVER THE NORTHERN HALF...ESPECIALLY NORTHWEST ZONES. FURTHER UPDATES TO FORECAST ARE POSSIBLE THIS EVENING IF IT APPEARS LIGHT RAIN WILL BE MORE WIDESPREAD. IN ADDITION...SHARP PRESSURE RISE BEHIND FRONT IS RESULTING IN A BRIEF PERIOD OF GUSTY WINDS OF 20-30 KTS AS NOTED ON SURFACE OBS SUCH AS KCGI. DUE TO THE BRIEF DURATION OF THESE GUSTIER WINDS...WILL NOT MENTION EXPLICITLY IN GRIDS/ZONES. ALSO ADJUSTED CLOUD COVER AND OTHER GRIDS BASED ON LATEST OBS. SHAMBURGER PREV DISCUSSION... /ISSUED 820 PM CDT TUE OCT 22 2013/ UPDATE...FOR 00Z TAFS... AVIATION... LOW PRESSURE CENTERED OVER SOUTHERN ILLINOIS WILL PUSH A NARROW SLOW MOVING BAND OF CLOUDS ACROSS THE NORTHERN PORTION OF MIDDLE TENNESSEE THIS EVENING. A FEW SHOWERS LOCATED OVER SOUTHEASTERN MISSOURI EXPECTED TO WEAKEN BEFORE ENTERING MIDDLE TENNESSEE... HOWEVER WINDS EXPECTED TO STAY STEADY AROUND 08 KNOTS THROUGHOUT THE NIGHT AND INTO WEDNESDAY AS THE WEAK FRONT ASSOCIATED WITH THE PREVIOUSLY MENTIONED SHOWERS PUSHES THROUGH THE AREA. MAINLY VFR BKN TO OVC CONDITIONS AT ALL SITES WITH CIGS OCCASIONALLY FALLING TO 3000 FT AFTER 03Z AT CSV. SKIES BECOME SCATTERED TO CLEAR DURING THE DAY ON WEDNESDAY AS THE LOW PRESSURE SYSTEM MOVES EAST. PREV DISCUSSION... /ISSUED 237 PM CDT TUE OCT 22 2013/ SHORT TERM...AT 2PM THIS AFTERNOON, A COLD FRONT STRETCHED FROM JUST NORTH OF MUSCLE SHOALS, ALABAMA TO JUST NORTH OF CROSSVILLE, TENNESSEE. A BAND OF CLOUDS, ASSOCIATED WITH THE FRONT, COVERED MUCH OF EASTERN AND SOUTHERN MIDDLE TENNESSEE WITH THE BACK EDGE OF THE BKN-TO-OVC CLOUDS LOCATED NEAR A LAWRENCEBURG TO CELINA LINE. AT 2PM...TEMPERATURES RANGED FROM NEAR 60 DEGREES IN THE SUNNY NORTHWEST TO NEAR 50 IN THE CLOUDIER SECTIONS OF THE UPPER CUMBERLAND. EVEN THOUGH CLOUDS SHOULD CONTINUE CLEARING FROM THE WEST, THEY PROBABLY WON`T CLEAR FAST ENOUGH ALONG THE UPPER CUMBERLAND TO ALLOW FOR HIGH TEMPERATURES TO PUSH MUCH MORE THAN A FEW DEGS ABOVE WHAT THEY ARE RIGHT NOW. STILL LOOKS LIKE A COLD FRONT WILL SWEEP ACROSS THE AREA TONIGHT, WITH AN AREA OF BKN STRATOCU LIKELY TO PUSH ACROSS NORTHERN AND EASTERN SECTIONS OF THE MID STATE, AS THE SURFACE LOW ZIPS FROM NORTHERN MISSOURI THIS AFTERNOON TO EASTERN KENTUCKY BY LATE TONIGHT. SINCE OUR ATMOSPHERE SHOULD REMAIN PRETTY DRY, LOOK FOR ONLY A SLIGHT CHANCE FOR SHOWERS OVER THE NORTH TONIGHT AND WEDNESDAY MORNING, MAINLY IN AREAS NEAR THE KENTUCKY LINE. DON`T LOOK FOR MUCH MORE THAN A 10 TO 15 DEG TEMPERATURE RISE DURING THE DAYLIGHT HOURS ON WEDNESDAY, WITH AFTERNOON HIGHS MAINLY BETWEEN 50 AND 55 DEGREES. ALONG WITH SOME FRESH NORTHWEST BREEZES AT 10 TO 15 MPH, THOSE TEMPERATURES SHOULD FEEL PRETTY DOGGONE CHILLY--ESPECIALLY CONSIDERING THE FACT THAT OUR TEMPERATURES WILL BE AVERAGING SOME 15 DEGREES BELOW NORMAL TOMORROW. THE STRONGEST COLD AIR OUTBREAK OF THE SEASON WILL ARRIVE, FRESH OUT OF CANADA, ON THURSDAY AND LINGER INTO SATURDAY MORNING, WITH MID STATE LOW TEMPERATURES LIKELY TO AVERAGE SOME 15 TO 20 DEGREES BELOW NORMAL BY FRIDAY MORNING AND SATURDAY MORNING. NIGHTTIME FREEZING TEMPERATURES WILL BECOME INCREASINGLY LIKELY LATE THIS WEEK, WITH WIDESPREAD FREEZING TEMPERATURES AND WIDESPREAD FROST EXPECTED OVER THE AREA SATURDAY MORNING, AND EVEN THE POSSIBILITY OF A HARD KILLING FREEZE IN SOME AREAS (ESPECIALLY ALONG THE CUMBERLAND PLATEAU). AS A RESULT, WILL UPDATE THE HWO TO GO WITH A FREEZE OUTLOOK FOR LATE WEEK, AND WOULDN`T BE SURPRISED IF WE NEED TO ISSUE A FREEZE WATCH SOMETIME OVER THE NEXT 24 HRS. THE LOW TEMPERATURE AT NASHVILLE IS FORECAST TO HIT 32 DEGREES FRIDAY MORNING, AND THEN SINK TO 30 DEGREES SATURDAY MORNING. THE NORMALLY COLDER OUTLYING AREAS WILL PROBABLY SEE LOWS SATURDAY MORNING IN THE MIDDLE AND UPPER 20S! LONG TERM...AFTER THE LATE WEEK COLD SNAP, LOOK FOR AT LEAST A TEMPORARY TURN TO MILDER CONDITIONS, WITH UPPER FLOW BY EARLY NEXT WEEK BECOMING MORE ZONAL. AS A RESULT, EXPECT HIGH TEMPS TO FINALLY PUSH CLOSER TO NORMAL AND BE UP AROUND 70 AT NASHVILLE BY NEXT MONDAY AND TUESDAY. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 11
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
936 AM MDT WED OCT 23 2013 .UPDATE... && .SHORT TERM...CURRENT FORECASTS LOOK REASONABLE AT THIS TIME. WEAK SURGE STILL EXPECTED TO MOVE ACROSS THE PLAINS DURING THE AFTERNOON. WITH MID LEVEL INVERSION IN PLACE...HIGHS SHOULD WARM ONLY INTO THE LOWER 60S. SKIES TO BE MAINLY CLEAR THROUGH THE EVENING WITH THE EXCEPTION OF THE FAR NORTHEAST CORNER WHERE SOME MID LEVEL CLOUD WILL SPREAD INTO THE AREA DURING THE AFTERNOON. STILL LOOKING AT THE POTENTIAL FOR LOW STRATUS AND FOG DEVELOPING AFTER MIDNIGHT AS LOW LEVEL MOISTURE INCREASES. LATEST RAP AND NAM SHOWING THE DEVELOPMENT OF A DENVER CYCLONE WHICH COULD AID IN LOW CLOUDS AND FOG ADVECTING ACROSS THE DENVER AREA OVERNIGHT. THIS ALREADY NOTED IN SKY AND WEATHER GRIDS...LOOKS FINE FOR NOW. .AVIATION...LIGHT AND VARIABLE WINDS ACROSS AREA AIRPORTS AT THIS TIME. WEAK FRONT TO MOVE INTO THE AREA DURING THE AFTERNOON... WHICH SHOULD KEEP A NORTH TO NORTHEAST WIND COMPONENT IN PLACE WITH SPEEDS AROUND 8 KTS OR LESS. PERHAPS ENOUGH LOW LEVEL MOISTURE TO GENERATE A FEW CLOUDS AROUND 5000 FEET AGL AFTER 00Z. POTENTIAL FOR THE DEVELOPMENT AND/OR ADVECTION OF LOW CLOUDS AND FOG AFTER 06Z AS LOW LEVEL MOISTURE INCREASES. LATEST RUC AND NAM SUGGESTING A WEAK DENVER CYCLONE IN PLACE JUST WEST OF DIA AROUND 08Z. OVERALL...CURRENT TAF TRENDS LOOK REASONABLE...BUT WILL BE INCLUDING A TEMPO 1SM BR OVC001 BETWEEN 10Z AND 14Z AS CONFIDENCE IS INCREASING A BIT. VISIBILITIES MAY WELL END UP LOWER...MAINLY AT KDEN AND KBJC. FOR NOW WILL GO WITH THE MFR CONDITIONS. THINGS SHOULD IMPROVE BY 17Z AS AIRMASS DRIES OUT. && .PREV DISCUSSION... /ISSUED 413 AM MDT WED OCT 23 2013/ SHORT TERM...ANOTHER SUNNY DAY IS EXPECTED ALTHOUGH TEMPERATURES WILL LIKELY BE A COUPLE DEGREES COOLER AS A WEAK BACKDOOR COLD FRONT PUSHES ACROSS THE PLAINS LATER THIS MORNING. MAIN CLOUD DECK WILL HOLD JUST NORTHEAST OF THE FORECAST AREA WITH ONLY THE FAR NORTHEAST CORNER BEING CLIPPED BY THE MID LEVEL CLOUDINESS. FOR TONIGHT...MAIN CONCERN WILL SHIFT TOWARD STRATUS/FOG DEVELOPMENT AS LOW LEVEL MOISTURE AND EAST/SOUTHEAST LOW LEVEL WILL BE IN PLACE THROUGH THE NIGHT. THERE MAY BE A COMBINATION OF ADVECTION FOG/STRATUS ON THE EASTERN PLAINS AND A RADIATIONAL FOG COMPONENT FROM NORTH DENVER-FORT COLLINS-GREELEY WHERE STRATUS DECK WILL BE SLOWER TO DEVELOP...IF IT DEVELOPS. WEAK DENVER CYCLONE SURFACE FLOW WOULD ALSO LEND TOWARD LOCAL FOG DEVELOPMENT. WILL MENTION SOME FOG OVER THE PLAINS AND ADD MORE CLOUD COVER TO THE LATE NIGHT FORECAST. LONG TERM...A PERSISTENT UPPER RIDGE WILL REMAIN IN PLACE OVER THE WESTERN U.S. THROUGH THE WEEKEND...KEEPING SKIES ACROSS COLORADO MOSTLY CLEAR AND TEMPERATURES WARMER THAN NORMAL. AFTER A LITTLE BIT OF LOW CLOUDS OR FOG THURSDAY MORNING AND AFTERNOON TEMPERATURES CLOSE TO 60 ACROSS THE PLAINS...FRIDAY THROUGH SUNDAY WILL BE WARMER AND MOSTLY SUNNY. SUNDAY WILL BE THE WARMEST OF THE DAYS WITH HIGHS APPROACHING 70 DEGREES. CHANGES START OCCURRING ON MONDAY AS A VIGOROUS UPPER LEVEL TROUGH IS FORECAST TO MOVE OUT OF THE CANADIAN ROCKIES AND ACROSS THE INTERMOUNTAIN WEST. EACH OF THE SYNOPTIC MODELS HAS ITS OWN SOLUTION FOR THE STRENGTH AND POSITION OF THE TROUGH AS IT MOVES SOUTHWARD FROM CANADA. THE GFS TAKES A DEEPER SYSTEM FURTHER TO THE WEST WHILE THE ECMWF BRINGS THE TROUGH OVER WESTERN COLORADO BY TUESDAY MORNING. ENSEMBLE RUNS FROM THE MODELS ARE SHOWING EVEN MORE VARIETY IN THEIR SOLUTIONS...SOME OF WHICH KEEP WARM AIR IN PLACE OVER EASTERN COLORADO AS THE UPPER TROUGH CUTS OFF OVER CALIFORNIA AND NEVADA. THE ACCEPTED SOLUTION HAS BEEN CLOSEST TO THE ECMWF WHICH HAS SOME 15 DEGREES OF COOLING ON MONDAY AND ANOTHER 10 DEGREES OF COOLING TUESDAY. RAIN AND SNOW WILL ALSO RESULT WITH ALL THE DYNAMIC LIFT ASSOCIATED WITH THE UPPER TROUGH. HAVE HELD THE POPS IN THE CHANCE CATEGORY FOR THE TIME BEING. OVER THE NEXT DAY OR SO...WE SHOULD BEGIN SEEING MODEL SOLUTIONS CONVERGING ON A COMMON SOLUTION. AVIATION...NEARLY CLOUD FREE SKIES CAN BE EXPECTED THROUGH 00Z THURSDAY...THEN SHOULD SEE A FEW-SCT CLOUDS AROUND 5000 FT AGL DEVELOP THEREAFTER. MAIN CONCERN SURROUNDS WEAK DENVER CYCLONE AND POTENTIAL FOG DEVELOPMENT TOWARD 10Z-12Z THURSDAY WITH NARROWING T/TD SPREADS. FOG THREAT MOST LIKELY HINGES ON EXACT LOCATION AND EVOLUTION OF THE WEAK CYCLONE...BUT IF WINDS GO WNW/NW LATE TONIGHT THEN COULD BE LOOKING AT LOCALLY DENSE FOG MAINLY AT KDEN AND KBJC TIL AROUND 15Z THURSDAY. HYDROLOGY...NO PRECIPITATION WILL OCCUR THROUGH THIS WEEKEND. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...D-L LONG TERM....DANKERS AVIATION...D-L
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
907 AM CDT WED OCT 23 2013 .DISCUSSION... 327 AM CDT AFTER LOOKING LIKE EARLY WINTER YESTERDAY IT WILL CONTINUE TO FEEL AS SUCH FOR A COUPLE DAYS...WITH THE FORECAST CHALLENGES TIED TO WELL BELOW NORMAL TEMPERATURES THESE NEXT FEW DAYS AND THEN SWINGING BACK TO CLOSER TO NORMAL THIS WEEKEND AND MAYBE MORE SO INTO EARLY NEXT WEEK. SYNOPSIS...THE PESKY CLIPPER SYSTEM FROM YESTERDAY IS RACING EASTWARD ACROSS THE UPPER OHIO VALLEY EARLY THIS MORNING. IN ITS WAKE 70M HEIGHT FALLS WERE OBSERVED AT 500MB LAST EVE AS THE LARGE SCALE LONG WAVE TROUGH ACROSS EASTERN/CENTRAL NORTH AMERICA CONTINUES TO BE RE-ESTABLISHED. THAT WILL REMAIN THE DOMINANT INFLUENCE ON THE LOCAL WEATHER PATTERN THIS WEEK...WITH PERSISTENT UPPER LEVEL NORTHWEST FLOW. A SERIES OF MID-LEVEL PERTURBATIONS WILL TRAVERSE IN THIS FLOW TODAY AND TONIGHT...AGAIN FURTHER LEADING TO LOWERED HEIGHTS AND COLD ADVECTION. WITH HIGH PRESSURE REMAINING ACROSS THE CENTRAL PLAINS ALLOWING FOR NO RETURN LOW-LEVEL FLOW...THIS ENABLES AN IDEAL REGIME FOR TEMPERATURES TO REMAIN COLD BY MID-AUTUMN STANDARDS. EARLY THIS MORNING...LOW-LEVEL CONVERGENCE OVER THE LAKE HAS BEEN NOTED IN OBSERVATIONS AND EARLIER WAS ANALYZED FROM MID-LAKE INTO PORTER COUNTY. BUT THIS HAS SHIFTED EAST AND MOST OF THE DEVELOPMENT IS MOVING SOUTHEAST FROM IT...SO ALL IN ALL MOST IF NOT ALL OF PORTER COUNTY LOOKS TO REMAIN FREE OF THE CONVECTIVE SHOWERS OVER THE LAKE THIS MORNING. TODAY AND TONIGHT...MULTIPLE COMPACT AND SHEARED SHORT WAVES ARE NOTED ON THE CYCLONIC SIDE OF THE STRONG UPPER JET FROM MANITOBA INTO THE CORN BELT. UPSTREAM RADAR IMAGERY AND OBSERVATIONS ACROSS MN HAVE INDICATED SOME SNOW SHOWERS WITH THESE. ADD TO THAT SOME MORNING SUNSHINE ACROSS PARTS OF OUR CWA...AND WE SHOULD QUICKLY DESTABILIZE IN THE IMMEDIATE LOW-LEVELS UNDER THESE FEATURES. NAM AND RAP FORECAST BUFR SOUNDINGS FOR OUR FORECAST NOON TEMPS BOTH YIELD ALMOST 100 J/KG OF CAPE. WET BULB ZEROS WERE ANALYZED ON LAST NIGHTS RAOBS AND FORECAST BY TODAYS SOUNDINGS TO BE ONLY AROUND 1000 FT AGL. SO WOULD EXPECT ANY ISOLATED DEVELOPMENT TO BE MAINLY SNOW SHOWERS/FLURRIES. ITS POSSIBLE A COUPLE OF THESE PRODUCE BRIEF MODERATE RATES...BUT WOULD BE VERY TEMPORARY LASTING. HIGHS TODAY SHOULD BE LOWER TO MID 40S BASED ON CLIMATOLOGY FOR 850MB TEMPS OF AROUND -6C AND CONSIDERING THAT CLOUDS SHOULD FILL IN BY AFTERNOON. SOME FLURRIES MAY LINGER THIS EVENING...BUT TOUGH TO PLACE WHERE THOSE COULD BE RIGHT NOW. ALSO CHALLENGING TO FORESEE THE EVOLUTION OF THE CLOUD FIELD TONIGHT...WITH SOME INEVITABLE STRATOCU HOLES AND MAYBE EVEN EVENTUALLY FULL CLEARING LATE. SO MINS COULD VARY QUITE A BIT...BUT EXPECTING WIDESPREAD 20S IN OUTLYING AREAS. THURSDAY AND FRIDAY...THE IMPRESSIVE...IN FACT NEAR RECORD COLD AIR AT 850MB FOR THIS TIME OF YEAR...WILL MOVE OVER THE REGION ON THURSDAY AND THURSDAY NIGHT. THE MINIMUM 850MB TEMPERATURE ON THE DVN/ILX UPPER AIR PERIODS OF RECORD ARE RIGHT AROUND THE FORECAST OF -10C. SO THIS SETS THE STAGE FOR POTENTIAL RECORD COLD ON THU NIGHT WHEN A CLEAR SKY IS PROBABLE AND LIKELY RAPID DECOUPLING IN THE EVENING SHOULD ALLOW FOR QUICK DIMINISHING OF WINDS. WITH THU HIGHS AGAIN ONLY IN THE LOWER...TO POSSIBLY MID 40S...THE LOW STARTING POINT GOING INTO THE NIGHT WILL ALSO HELP. HAVE THU NIGHT LOWS FORECAST IN THE LOWER TO MID 20S...WITH LIKELY SOME UPPER TEENS IF THE LOWER 20S ARE WIDESPREAD. DOWNTOWN CHICAGO MAY ALSO SEE THEIR FIRST FREEZE. FRIDAY WILL HAVE A SLOW MODERATION IN TEMPS AND THEN RETURN FLOW FRIDAY NIGHT...WHICH IS WELL AGREED UPON IN GUIDANCE...LOOKS TO WARM TEMPS OVERNIGHT INTO SATURDAY. THIS WEEKEND AND EARLY NEXT WEEK...GUIDANCE BEGINS TO QUICKLY SHOW SPREAD THROUGH THIS PERIOD...BUT FOR THE MOST IS IN STRONG AGREEMENT OF A COLD FRONT DROPPING THROUGH ON SATURDAY. IF EARLY ENOUGH THIS MAY BRING AN AFTERNOON DROP IN TEMPERATURES. NOT MUCH THERE FOR FORCING OR SATURATION IN CURRENT GUIDANCE TO SUPPORT ANY POPS WITH THIS. AS THE TRAIN OF SYSTEMS IN NW FLOW ACROSS CANADA CONTINUES...A STRONG COLD FRONT APPROACHES THE AREA BY MONDAY...BUT THIS GETS HUNG UP AS AN UPPER LOW DIGS IN THE WESTERN U.S. AND FORCES HEIGHT RISES OVER THE REGION. THIS FRONT IS WIDELY DISAGREED UPON ON GUIDANCE AND SHOULD SERVE AS A PRETTY GOOD FOCUS FOR PRECIP WHERE IT BEGINS TO LIFT NORTH AS A WARM FRONT. TEMPS MAY BE MUCH COOLER UNDER THIS PRECIP...BUT TO THE SOUTH AT OR MAYBE EVEN ABOVE NORMAL. MTF && .CLIMATE... RECORD LOW TEMPERATURES IN OUTLYING AREAS MAY BE APPROACHED OR SET FRIDAY MORNING IF CLOUDS DEPART AS FORECAST. FOR CHICAGO...THE CLIMATE PERIOD OF RECORD INCLUDES SOME COLDER YEARS IN THE 1880S...WITH THE RECORD LOW BEING IN THE TEENS WHICH WILL VERY LIKELY NOT BE APPROACHED AT OHARE. BUT FOR OUR OTHER LONG TERM CLIMATE SITE OF ROCKFORD WHICH DATES BACK TO 1905...IT IS VERY POSSIBLE. RECORD LOW FOR ROCKFORD ON OCTOBER 25TH: 23 (1987) MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * NONE. KREIN //DISCUSSION...UPDATED 12Z... HIGH PRESSURE IS OVER THE CENTRAL PLAINS AND NORTHWEST FLOW HAS RETURNED TO THE REGION. PATCHY VFR STRATUS IS MOVING EAST ACROSS NORTHERN ILLINOIS AND EXPECTING THE STRATUS TO BECOME MORE WIDESPREAD LATE THIS MORNING INTO THIS AFTERNOON. ISOLATED FLURRIES ARE POSSIBLE AT RFD THIS AFTN BUT THINKING THEY WILL BE ISOLATED ENOUGH TO LEAVE OUT OF THE TAF FOR NOW. EXPECTING DRY CONDITIONS EVERYWHERE ELSE AS LAKE EFFECT SHOWERS WILL REMAIN EAST OF GYY. NW WINDS WILL BEGIN GUSTING TO 15-20 KT THIS MORNING AND THEN GUSTS WILL DIMINISH THIS EVENING AT ALL LOCATIONS BUT GYY. DUE TO THE ONSHORE WIND COMPONENT...THINKING GUSTS WILL TAKE A LITTLE LONGER TO DIMINISH. THE PRESSURE GRADIENT WILL REMAIN TIGHT TONIGHT AND WINDS ALONG THE LAKE SHOULD BE NW AROUND 10 KT. SITES FARTHER FROM THE LAKE WILL HAVE SLIGHTLY LIGHTER WIND SPEEDS AROUND 8 KT. CLOUDS SHOULD ALSO THIN OVERNIGHT AND REMAIN SCATTERED TOMORROW. NW WINDS GUSTING TO AROUND 15 KT ARE EXPECTED AGAIN TOMORROW WITH OTHERWISE VFR CONDITIONS. JEE //ORD AND MDW CONFIDENCE...UPDATED 14Z... * VFR CIGS MAY BE A LITTLE SLOWER TO MOVE IN...BUT OTHERWISE HIGH CONFIDENCE IN ALL FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...CHANCE OF SHRA...MVFR POSSIBLE OVERNIGHT. TUESDAY...CHANCE OF SHRA...MVFR POSSIBLE. JEE && .MARINE... 315 AM CDT LOW PRESSURE IS OVER SE INDIANA WHILE A WEAK HIGH PRESSURE SINKS SOUTH OVER THE GULF COAST THIS EVENING. A SECOND WEAKER LOW OVER THE NORTHERN ROCKIES WILL ALSO TRAVEL DOWN THE PLAINS DISSIPATING OVER TEXAS THIS EVENING. A MUCH LARGER HIGH WILL BUILD OVER THE PLAINS TONIGHT THROUGH THURSDAY WITH NORTHWEST WINDS 15-25 KT EXPECTED ACROSS THE LAKE. THERE IS A CHANCE OF WATERSPOUTS ACROSS THE EASTERN SIDE OF THE LAKE AGAIN TODAY. HAZARDOUS WAVES ARE STILL EXPECTED ACROSS THE NEARSHORE WATERS TODAY AND WAVES WILL DIMINISH FOR A FEW HOURS LATE THIS EVENING ACROSS THE IL SIDE OF THE LAKE. HAZARDOUS WAVES WILL BUILD BACK EARLY THURSDAY MORNING SO ANOTHER SMALL CRAFT ADVISORY WILL BE NEEDED OVER THE IL NEARSHORE WATERS. WAVES FINALLY SUBSIDE TO BELOW SMALL CRAFT CRITERIA FRIDAY AFTERNOON. THE HIGH WILL SPREAD ACROSS THE SE US FRIDAY AND OVER THE WEEKEND WHILE A STRONG LOW PASSES OVER THE NORTHERN GREAT LAKES FRIDAY NIGHT AND SATURDAY. THE GRADIENT OVER THE LAKE WILL TIGHTEN DRAMATICALLY THEREFORE PUT LOW END GALES INTO THE FORECAST FOR FRIDAY NIGHT ACROSS THE LAKE. WINDS TURN NORTHWEST BEHIND THE LOWS COLD FRONT AND A BRIEF PERIOD OF NORTHWEST GALES IS ALSO POSSIBLE SATURDAY EVENING. GUIDANCE THEN BEGINS TO DIFFER SIGNIFICANTLY WITH WHAT THE NEXT HIGH AND LOW PAIR WILL DO. IN GENERAL LOOKING AT LIGHT WEST TO SOUTHWEST WINDS SUNDAY WITH A BACKDOOR COLD FRONT POSSIBLE LATE SUNDAY NIGHT INTO MONDAY. THEN EAST WINDS ARE EXPECTED EARLY NEXT WEEK. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM WEDNESDAY. && $$ 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
NWS CHICAGO/ROMEOVILLE IL
645 AM CDT WED OCT 23 2013 .DISCUSSION... 327 AM CDT AFTER LOOKING LIKE EARLY WINTER YESTERDAY IT WILL CONTINUE TO FEEL AS SUCH FOR A COUPLE DAYS...WITH THE FORECAST CHALLENGES TIED TO WELL BELOW NORMAL TEMPERATURES THESE NEXT FEW DAYS AND THEN SWINGING BACK TO CLOSER TO NORMAL THIS WEEKEND AND MAYBE MORE SO INTO EARLY NEXT WEEK. SYNOPSIS...THE PESKY CLIPPER SYSTEM FROM YESTERDAY IS RACING EASTWARD ACROSS THE UPPER OHIO VALLEY EARLY THIS MORNING. IN ITS WAKE 70M HEIGHT FALLS WERE OBSERVED AT 500MB LAST EVE AS THE LARGE SCALE LONG WAVE TROUGH ACROSS EASTERN/CENTRAL NORTH AMERICA CONTINUES TO BE RE-ESTABLISHED. THAT WILL REMAIN THE DOMINANT INFLUENCE ON THE LOCAL WEATHER PATTERN THIS WEEK...WITH PERSISTENT UPPER LEVEL NORTHWEST FLOW. A SERIES OF MID-LEVEL PERTURBATIONS WILL TRAVERSE IN THIS FLOW TODAY AND TONIGHT...AGAIN FURTHER LEADING TO LOWERED HEIGHTS AND COLD ADVECTION. WITH HIGH PRESSURE REMAINING ACROSS THE CENTRAL PLAINS ALLOWING FOR NO RETURN LOW-LEVEL FLOW...THIS ENABLES AN IDEAL REGIME FOR TEMPERATURES TO REMAIN COLD BY MID-AUTUMN STANDARDS. EARLY THIS MORNING...LOW-LEVEL CONVERGENCE OVER THE LAKE HAS BEEN NOTED IN OBSERVATIONS AND EARLIER WAS ANALYZED FROM MID-LAKE INTO PORTER COUNTY. BUT THIS HAS SHIFTED EAST AND MOST OF THE DEVELOPMENT IS MOVING SOUTHEAST FROM IT...SO ALL IN ALL MOST IF NOT ALL OF PORTER COUNTY LOOKS TO REMAIN FREE OF THE CONVECTIVE SHOWERS OVER THE LAKE THIS MORNING. TODAY AND TONIGHT...MULTIPLE COMPACT AND SHEARED SHORT WAVES ARE NOTED ON THE CYCLONIC SIDE OF THE STRONG UPPER JET FROM MANITOBA INTO THE CORN BELT. UPSTREAM RADAR IMAGERY AND OBSERVATIONS ACROSS MN HAVE INDICATED SOME SNOW SHOWERS WITH THESE. ADD TO THAT SOME MORNING SUNSHINE ACROSS PARTS OF OUR CWA...AND WE SHOULD QUICKLY DESTABILIZE IN THE IMMEDIATE LOW-LEVELS UNDER THESE FEATURES. NAM AND RAP FORECAST BUFR SOUNDINGS FOR OUR FORECAST NOON TEMPS BOTH YIELD ALMOST 100 J/KG OF CAPE. WET BULB ZEROS WERE ANALYZED ON LAST NIGHTS RAOBS AND FORECAST BY TODAYS SOUNDINGS TO BE ONLY AROUND 1000 FT AGL. SO WOULD EXPECT ANY ISOLATED DEVELOPMENT TO BE MAINLY SNOW SHOWERS/FLURRIES. ITS POSSIBLE A COUPLE OF THESE PRODUCE BRIEF MODERATE RATES...BUT WOULD BE VERY TEMPORARY LASTING. HIGHS TODAY SHOULD BE LOWER TO MID 40S BASED ON CLIMATOLOGY FOR 850MB TEMPS OF AROUND -6C AND CONSIDERING THAT CLOUDS SHOULD FILL IN BY AFTERNOON. SOME FLURRIES MAY LINGER THIS EVENING...BUT TOUGH TO PLACE WHERE THOSE COULD BE RIGHT NOW. ALSO CHALLENGING TO FORESEE THE EVOLUTION OF THE CLOUD FIELD TONIGHT...WITH SOME INEVITABLE STRATOCU HOLES AND MAYBE EVEN EVENTUALLY FULL CLEARING LATE. SO MINS COULD VARY QUITE A BIT...BUT EXPECTING WIDESPREAD 20S IN OUTLYING AREAS. THURSDAY AND FRIDAY...THE IMPRESSIVE...IN FACT NEAR RECORD COLD AIR AT 850MB FOR THIS TIME OF YEAR...WILL MOVE OVER THE REGION ON THURSDAY AND THURSDAY NIGHT. THE MINIMUM 850MB TEMPERATURE ON THE DVN/ILX UPPER AIR PERIODS OF RECORD ARE RIGHT AROUND THE FORECAST OF -10C. SO THIS SETS THE STAGE FOR POTENTIAL RECORD COLD ON THU NIGHT WHEN A CLEAR SKY IS PROBABLE AND LIKELY RAPID DECOUPLING IN THE EVENING SHOULD ALLOW FOR QUICK DIMINISHING OF WINDS. WITH THU HIGHS AGAIN ONLY IN THE LOWER...TO POSSIBLY MID 40S...THE LOW STARTING POINT GOING INTO THE NIGHT WILL ALSO HELP. HAVE THU NIGHT LOWS FORECAST IN THE LOWER TO MID 20S...WITH LIKELY SOME UPPER TEENS IF THE LOWER 20S ARE WIDESPREAD. DOWNTOWN CHICAGO MAY ALSO SEE THEIR FIRST FREEZE. FRIDAY WILL HAVE A SLOW MODERATION IN TEMPS AND THEN RETURN FLOW FRIDAY NIGHT...WHICH IS WELL AGREED UPON IN GUIDANCE...LOOKS TO WARM TEMPS OVERNIGHT INTO SATURDAY. THIS WEEKEND AND EARLY NEXT WEEK...GUIDANCE BEGINS TO QUICKLY SHOW SPREAD THROUGH THIS PERIOD...BUT FOR THE MOST IS IN STRONG AGREEMENT OF A COLD FRONT DROPPING THROUGH ON SATURDAY. IF EARLY ENOUGH THIS MAY BRING AN AFTERNOON DROP IN TEMPERATURES. NOT MUCH THERE FOR FORCING OR SATURATION IN CURRENT GUIDANCE TO SUPPORT ANY POPS WITH THIS. AS THE TRAIN OF SYSTEMS IN NW FLOW ACROSS CANADA CONTINUES...A STRONG COLD FRONT APPROACHES THE AREA BY MONDAY...BUT THIS GETS HUNG UP AS AN UPPER LOW DIGS IN THE WESTERN U.S. AND FORCES HEIGHT RISES OVER THE REGION. THIS FRONT IS WIDELY DISAGREED UPON ON GUIDANCE AND SHOULD SERVE AS A PRETTY GOOD FOCUS FOR PRECIP WHERE IT BEGINS TO LIFT NORTH AS A WARM FRONT. TEMPS MAY BE MUCH COOLER UNDER THIS PRECIP...BUT TO THE SOUTH AT OR MAYBE EVEN ABOVE NORMAL. MTF && .CLIMATE...450 AM CDT RECORD LOW TEMPERATURES IN OUTLYING AREAS MAY BE APPROACHED OR SET FRIDAY MORNING IF CLOUDS DEPART AS FORECAST. FOR CHICAGO...THE CLIMATE PERIOD OF RECORD INCLUDES SOME COLDER YEARS IN THE 1880S...WITH THE RECORD LOW BEING IN THE TEENS WHICH WILL VERY LIKELY NOT BE APPROACHED AT OHARE. BUT FOR OUR OTHER LONG TERM CLIMATE SITE OF ROCKFORD WHICH DATES BACK TO 1905...IT IS VERY POSSIBLE. RECORD LOW FOR ROCKFORD ON OCTOBER 25TH: 23 (1987) MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 12Z... * NONE. JEE //DISCUSSION...UPDATED 12Z... HIGH PRESSURE IS OVER THE CENTRAL PLAINS AND NORTHWEST FLOW HAS RETURNED TO THE REGION. PATCHY VFR STRATUS IS MOVING EAST ACROSS NORTHERN ILLINOIS AND EXPECTING THE STRATUS TO BECOME MORE WIDESPREAD LATE THIS MORNING INTO THIS AFTERNOON. ISOLATED FLURRIES ARE POSSIBLE AT RFD THIS AFTN BUT THINKING THEY WILL BE ISOLATED ENOUGH TO LEAVE OUT OF THE TAF FOR NOW. EXPECTING DRY CONDITIONS EVERYWHERE ELSE AS LAKE EFFECT SHOWERS WILL REMAIN EAST OF GYY. NW WINDS WILL BEGIN GUSTING TO 15-20 KT THIS MORNING AND THEN GUSTS WILL DIMINISH THIS EVENING AT ALL LOCATIONS BUT GYY. DUE TO THE ONSHORE WIND COMPONENT...THINKING GUSTS WILL TAKE A LITTLE LONGER TO DIMINISH. THE PRESSURE GRADIENT WILL REMAIN TIGHT TONIGHT AND WINDS ALONG THE LAKE SHOULD BE NW AROUND 10 KT. SITES FARTHER FROM THE LAKE WILL HAVE SLIGHTLY LIGHTER WIND SPEEDS AROUND 8 KT. CLOUDS SHOULD ALSO THIN OVERNIGHT AND REMAIN SCATTERED TOMORROW. NW WINDS GUSTING TO AROUND 15 KT ARE EXPECTED AGAIN TOMORROW WITH OTHERWISE VFR CONDITIONS. JEE //ORD AND MDW CONFIDENCE...UPDATED 12Z... * HIGH CONFIDENCE IN ALL FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...CHANCE OF SHRA...MVFR POSSIBLE OVERNIGHT. TUESDAY...CHANCE OF SHRA...MVFR POSSIBLE. JEE && .MARINE... 315 AM CDT LOW PRESSURE IS OVER SE INDIANA WHILE A WEAK HIGH PRESSURE SINKS SOUTH OVER THE GULF COAST THIS EVENING. A SECOND WEAKER LOW OVER THE NORTHERN ROCKIES WILL ALSO TRAVEL DOWN THE PLAINS DISSIPATING OVER TEXAS THIS EVENING. A MUCH LARGER HIGH WILL BUILD OVER THE PLAINS TONIGHT THROUGH THURSDAY WITH NORTHWEST WINDS 15-25 KT EXPECTED ACROSS THE LAKE. THERE IS A CHANCE OF WATERSPOUTS ACROSS THE EASTERN SIDE OF THE LAKE AGAIN TODAY. HAZARDOUS WAVES ARE STILL EXPECTED ACROSS THE NEARSHORE WATERS TODAY AND WAVES WILL DIMINISH FOR A FEW HOURS LATE THIS EVENING ACROSS THE IL SIDE OF THE LAKE. HAZARDOUS WAVES WILL BUILD BACK EARLY THURSDAY MORNING SO ANOTHER SMALL CRAFT ADVISORY WILL BE NEEDED OVER THE IL NEARSHORE WATERS. WAVES FINALLY SUBSIDE TO BELOW SMALL CRAFT CRITERIA FRIDAY AFTERNOON. THE HIGH WILL SPREAD ACROSS THE SE US FRIDAY AND OVER THE WEEKEND WHILE A STRONG LOW PASSES OVER THE NORTHERN GREAT LAKES FRIDAY NIGHT AND SATURDAY. THE GRADIENT OVER THE LAKE WILL TIGHTEN DRAMATICALLY THEREFORE PUT LOW END GALES INTO THE FORECAST FOR FRIDAY NIGHT ACROSS THE LAKE. WINDS TURN NORTHWEST BEHIND THE LOWS COLD FRONT AND A BRIEF PERIOD OF NORTHWEST GALES IS ALSO POSSIBLE SATURDAY EVENING. GUIDANCE THEN BEGINS TO DIFFER SIGNIFICANTLY WITH WHAT THE NEXT HIGH AND LOW PAIR WILL DO. IN GENERAL LOOKING AT LIGHT WEST TO SOUTHWEST WINDS SUNDAY WITH A BACKDOOR COLD FRONT POSSIBLE LATE SUNDAY NIGHT INTO MONDAY. THEN EAST WINDS ARE EXPECTED EARLY NEXT WEEK. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM WEDNESDAY. && $$ 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
NWS NORTHERN INDIANA
955 AM EDT WED OCT 23 2013 .SYNOPSIS... ISSUED AT 417 AM EDT WED OCT 23 2013 A SERIES OF DISTURBANCES WILL MOVE THROUGH THE REGION OVER THE NEXT COUPLE OF DAYS. LAKE EFFECT RAIN SHOWERS CAN BE EXPECTED ACROSS PORTIONS OF NORTHWESTERN INDIANA AND SOUTHWESTERN LOWER MICHIGAN OVER THE NEXT COUPLE OF DAYS AS THE COLD NORTHWESTERLY FLOW CONTINUES OVER THE WARM WATERS OF LAKE MICHIGAN. SNOW MAY BE MIXED AT TIMES WITH THE SHOWERS THIS MORNING AND AGAIN TONIGHT. AFTERNOON HIGH TEMPERATURES WILL CLIMB INTO THE LOWER TO MIDDLE 40S. OVERNIGHT LOWS WILL DROP BACK INTO THE LOWER 30S...EXCEPT MID 30S ALONG THE LAKESHORE. && .UPDATE... ISSUED AT 947 AM EDT WED OCT 23 2013 VSBYS HAVE IMPROVED OVER NE PORTION OF CWA AND UPDATED GRIDS/ZFP IN THIS AREA TO REMOVE FOG MENTION. LAKE EFFECT BAND ENHANCED BY MESO-LOW OVER SWRN MI CONTG OVER NW PORTION OF CWA. PERSISTENT PRECIP AND CONTD WK CAA HAVE ALLOWED PRECIP TO CHANGE OVER TO SNOW AT TIMES IN THIS AREA. SMALL CHANGES MADE TO FCST TO INCREASE POTENTIAL FOR SNOW SHOWERS IN THIS AREA WITH SOME MINOR ACCUMS. LAKE EFFECT BAND PARALLELING SERN LAKE MICHIGAN SHORELINE APPEARS TO BE MOVG SLOWLY ONSHORE SO EXPECT SOME DISRUPTION/DECREASE IN LAKE EFFECT SHOWERS OVER THE NEXT FEW HRS... THOUGH WEAKER BANDS WILL LIKELY DVLP THROUGH THE AFTN AS LAKE INDUCED INSTABILITY PERSISTS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 417 AM EDT WED OCT 23 2013 COMPACT UPPER LOW HAS BEEN STEADY PROGRESS ESE DURING THE EVENING/OVERNIGHT HOURS...WITH CENTER SOMEWHERE AROUND INDIANAPOLIS. WHILE RAIN HAS BEEN THE DOMINANT PTYPE...SOME REPORTS OF SNOW OR SLEET OCCURRING HAVE BEEN RECEIVED IN OUR FAR SOUTHERN COUNTIES WITH SOME SLUSHY LIGHT ACCUMULATIONS NOTED IN SOME AREAS. THIS AREA WILL CONTINUE TO PULL AWAY BY 12Z WEDS. FURTHER NORTH...FLOW IS BECOMING MORE N AND NW AND ALLOWING FOR EXPANDING DEVELOPMENT OF LAKE EFFECT SHOWERS ACROSS MUCH OF LAKE MI. THE GREATEST CONCENTRATION HAS BEEN RESIDING ALONG THE EASTERN HALF AND SOMEWHAT INLAND INTO WESTERN LWR MI. LAKE INDUCED INSTABILITY REMAINS IN THE MODERATE TO EXTREME CATEGORY (SFC-850 MB/SFC-700 MB DELTA T VALUES OF LOW 20S AND LOW 30S RESPECTIVELY) WITH LAKE BASED CAPES APPROACHING 1000 J/KG. AN OCCASIONAL REPORT OF SLEET/GRAUPEL HAVE COME IN ASSOCIATED WITH THE STRONGER SHOWERS. AS THIS SHOULD CONTINUE...HAVE ADDED MENTION OF SLEET IN CATEGORICAL AREAS. IN TERMS OF TIMING AND COVERAGE HRRR HAS A NICE HANDLE ON BOTH PRECIP TO THE SOUTH AND EVOLUTION OF LAKE EFFECT SHOWERS. EXPECTING A CHAOTIC PATTERN TO THE LAKE EFFECT SHOWERS INITIALLY AS SFC OBS INDICATING MESO LOW THAT WAS ADVERTISED ON HIGH RES MODELS PAST COUPLE OF DAYS HAS TAKEN SHAPE OVER THE SOUTHERN PART OF THE LAKE. THIS FEATURE WILL WORK SLOWLY SOUTH AND MOVE ONSHORE IN THE 9 TO 12Z WINDOW. HAVE EXPANDED CAT POPS FURTHER EAST INTO ALL OF BERRIEN AS WELL AS PART OF CASS AND ST JOE INDIANA COUNTIES TO COVER UPSTREAM TRENDS. CHANCES FOR SNOW/GRAUPEL WILL DECREASE AFTER 15Z AS TEMPS BEGIN TO WARM INTO THE 40S. FOR THIS AFTERNOON...HI RES MODELS SEEM TO LOWER OVERALL DEPTH OF MSTR BUT STILL LINGER A DECENT AMOUNT WHERE STRONGEST OMEGA RESIDES. IN ADDITION...INSTABILITY WILL REMAIN UNCHANGED. WHILE SOME CONCERN THAT COVERAGE COULD DIMINISH SOMEWHAT IN THE 19 TO 23Z RANGE WITH THIS DECREASE IN MSTR...WILL GO WITH INSTABILITY MAKING UP THE DIFFERENCE WITH HIGH LIKELY/LOW CAT POPS WARRANTED (AND EXPANDED SLIGHTLY TO BETTER REFLECT EXPECTED FLOW). NEXT WAVE OF INTEREST...PRESENTLY DIVING SE THROUGH THE DAKOTAS...WILL APPROACH LATER THIS AFTERNOON AND TONIGHT. TRACK OF THIS FEATURE WILL AGAIN BE TO THE SW OF THE AREA... TRACKING THROUGH WESTERN IOWA INTO SOUTHERN ILLINOIS. CLOUD COVER WILL INCREASE NORTHEAST OF THE FEATURE ACROSS THE AREA BUT PRECIP CHANCES LOOK TO BE CONFINED DOWNWIND OF LK MI AS NW FLOW WILL INCREASE...AND BOUNDARY LAYER MOISTURE WILL PICK UP ONCE AGAIN. INCREASED POPS SOMEWHAT TO HIGH END LIKELY FOR NOW BUT SUBSEQUENT INCREASE TO CAT POPS MAY BE NEEDED IN LATER FORECASTS. LOWS WILL DROP INTO THE LOW 30S IN MOST SPOTS AWAY FROM THE LAKE WHICH MAY RESULT IN AN GREATER CHANCE OF SNOW VS RAIN BUT GIVEN LAKE PROCESSES PRECIP MAY REMAIN MAINLY RAIN. WILL KEEP MIX MENTION FOR NOW. && .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 417 AM EDT WED OCT 23 2013 LARGE SCALE TROUGH EXPECTED TO REMAIN OVER THE GREAT LAKES THROUGH THE WEEKEND BEFORE PATTERN BEGINS TO RELOAD WITH RISING HEIGHTS AND MODERATING TEMPERATURES NEXT WEEK. LAKE EFFECT RAIN AND SNOW SHOWERS WILL BE PRIMARY CONCERN DURING THE BEGINNING OF THE LONG TERM PERIOD. WEAK SHORT WAVE AND SURFACE TROUGH TO PASS ACROSS THE AREA EARLY THU MORNING. THIS WILL HELP INCREASE SFC-700 DELTA T VALUES TO OVER 30 PROVIDING EXTREME INSTABILITY FROM LAKE MICHIGAN. LAKE INDUCED CAPE VALUES RISE TO OVER 800 J/KG WITH NEARLY UNIDIRECTIONAL NW FETCH. 1000-850MB RH REMAINS ABOVE 80 PERCENT SO SEE LITTLE REASON THAT LAKE EFFECT SHOWERS WILL NOT BE ONGOING. HAVE RAISED POPS TO CATEGORICAL ACROSS MI COUNTIES NEAR THE LAKE AND TAPERED FURTHER INLAND. PCPN TYPE WILL BE QUITE DIFFICULT AROUND THE LAKE AS MODIFIED BOUNDARY LAYER SHOULD KEEP PCPN MAINLY RAIN NEAR THE LAKE WITH A MIX OF RAIN AND SNOW INLAND WHERE THERMAL PROFILES MORE FAVORABLE FOR SNOW. HEAVIER SHOWERS TO BRING PERIODS OF MAINLY SNOW AND SLEET BUT FOR NOW HAVE KEPT FORECAST AS A RAIN/SNOW MIX GIVEN DIFFICULTY OF NAILING DOWN THESE MESOSCALE DETAILS AT THIS TIME RANGE. SOME MINOR SNOW ACCUMULATIONS ON GRASSY SURFACES WILL BE POSSIBLE AWAY FROM THE LAKE...ESPECIALLY THU NIGHT WITH DIURNAL COOLING AND CONTINUED EXTREME INSTABILITY AND FAVORABLE TRAJECTORIES. GIVEN THE INSTABILITY EXPECT SOME RATHER IMPRESSIVE RAINFALL TOTALS WHERE BANDS ARE PERSISTENT. LAKE EFFECT TO BEGIN WINDING DOWN LATER FRIDAY MORNING AS FLOW BACKS AHEAD OF NEXT APPROACHING SHORT WAVE AND INVERSION HEIGHTS LOWER WITH DECREASING MOISTURE. DELTA T VALUES REMAIN FAVORABLE FOR SOME LIGHTER SHOWERS CLOSER TO LAKE AND EVEN FRIDAY NIGHT WITH SOUTHWEST FLOW AFFECTING FAR NORTHERN BERRIEN COUNTY. ATMOSPHERE BECOMING RATHER DRY BY THIS TIME SO OPTED FOR JUST A SLIGHT CHANCE POP WITH SFC-850MB DELTA T VALUES STILL AROUND 20. A BRIEF MODERATION IN TEMPS EXPECTED SAT AHEAD OF NEXT SHORT WAVE AND COLD FRONT. TEMPS WILL STRONGLY DEPEND ON HOW FAST CLOUDS MOVE IN SATURDAY. SOUTHERN AREAS SHOULD SEE LOW TO MID 50S WHILE NORTHERN AREAS CLIMB TO NEAR 50. THIS CLIPPER WILL BRING ANOTHER BRIEF SHOT OF COLDER AIR AND A CHANCE FOR ADDITIONAL LAKE EFFECT RAIN SHOWERS. MEDIUM RANGE MODELS IN GOOD AGREEMENT ON LARGE SCALE PATTERN FOR EARLY NEXT WEEK AS WEST COAST ENERGY BEGINS TO CARVE OUT A NEW TROUGH OVER THE WESTERN CONUS. THIS ALLOWS HEIGHTS TO RISE OVER THE MIDWEST WITH MODERATING TEMPERATURES MONDAY AND TUESDAY. A COLD FRONT WILL SAG SOUTH AND BECOME NEARLY STATIONARY EITHER ACROSS OR JUST NORTH OF OUR AREA AS IT BECOMES PARALLEL TO MID LEVEL FLOW. THIS FRONT WILL BE FOCUS FOR SHOWERS MONDAY INTO TUESDAY AND EVEN WEDNESDAY OF NEXT WEEK. A LOT TO WATCH WITH THIS EVOLUTION AS WARM SECTOR WILL LIKELY BE RELATIVELY WARM FOR OCTOBER AND A NICE BAROCLINIC ZONE WILL SET NEAR OUR AREA. SURFACE WAVE DEVELOPMENT AROUND DAY 7 WILL HELP BACK WINDS AND STRONG 100 KNOT JET LOOKS TO RACE TOWARD THE AREA. KINEMATICS LOOK FAVORABLE FOR SEVERE WEATHER IN THE MIDWEST OR MID SOUTH BUT INSTABILITY REMAINS A BIG UNKNOWN. HOWEVER...CLIMATOLOGY FAVORS A SECONDARY SEVERE WEATHER PEAK IN OCTOBER FOR WEAK INSTABILITY/HIGH SHEAR SEVERE WEATHER EVENTS. CERTAINLY WORTH WATCHING NEXT SEVERAL DAYS IN MODEL EVOLUTION. PATTERN REMAINS QUITE ACTIVE GIVEN NUMEROUS PACIFIC/ASIAN CYCLONES OVER THE LAST FEW WEEKS WHICH HAVE HELPED AMPLIFY THE MID LEVEL FLOW AND DOWNSTREAM PATTERN OVER THE CONUS. LONGER RANGE OUTLOOK FOR DAY 7-10 ALSO LOOKS QUITE INTERESTING WITH WEST CONUS LOW EJECTION TOWARD THE AREA BY LATE NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 737 AM EDT WED OCT 23 2013 PATCHY DENSE FOG HAS DEVELOPED OVER NE INDIANA INCLUDING FWA TERMINAL. VSBYS EXPECTED TO IMPROVE THERE AROUND 1330Z AS MIXING STRENGTHENS. COLD AIR ALOFT AND CYCLONIC FLOW WILL PROMOTE STRATO CU ACROSS THE AREA AT LEAST THROUGH THIS EVE. CIGS SHOULD GENERALLY BE VFR EXCEPT OCNLY LOWER IN LAKE EFFECT SHOWERS AT SBN. FEW SHRA ALSO PSBL VCNTY OF FWA THIS AFTN BUT COVERAGE EXPECTED TO BE LESS IN NE INDIANA SO LEFT MENTION OUT OF TAFS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT FRIDAY FOR LMZ043-046. && $$ UPDATE...JT SYNOPSIS...FISHER SHORT TERM...FISHER LONG TERM...LASHLEY AVIATION...JT VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
757 AM EDT WED OCT 23 2013 .SYNOPSIS... ISSUED AT 417 AM EDT WED OCT 23 2013 A SERIES OF DISTURBANCES WILL MOVE THROUGH THE REGION OVER THE NEXT COUPLE OF DAYS. LAKE EFFECT RAIN SHOWERS CAN BE EXPECTED ACROSS PORTIONS OF NORTHWESTERN INDIANA AND SOUTHWESTERN LOWER MICHIGAN OVER THE NEXT COUPLE OF DAYS AS THE COLD NORTHWESTERLY FLOW CONTINUES OVER THE WARM WATERS OF LAKE MICHIGAN. SNOW MAY BE MIXED AT TIMES WITH THE SHOWERS THIS MORNING AND AGAIN TONIGHT. AFTERNOON HIGH TEMPERATURES WILL CLIMB INTO THE LOWER TO MIDDLE 40S. OVERNIGHT LOWS WILL DROP BACK INTO THE LOWER 30S...EXCEPT MID 30S ALONG THE LAKESHORE. && .UPDATE... UPDATED ZFP TO REMOVE PRE-DAWN WORDING AND ADD PATCHY DENSE FOG ACROSS THE NE EARLY TODAY. ALSO REMOVED POPS IN THIS AREA FOR THIS MORNING AS PRECIP ASSOCIATED WITH CLIPPER HAS MOVED SE OF THE CWA THIS MORNING. SOME LAKE EFFECT/INSTABILITY SHOWERS STILL PSBL LATER IN THE DAY IN THIS AREA. OTRWS... NO SGFNT CHANGES MADE TO GRIDS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 417 AM EDT WED OCT 23 2013 COMPACT UPPER LOW HAS BEEN STEADY PROGRESS ESE DURING THE EVENING/OVERNIGHT HOURS...WITH CENTER SOMEWHERE AROUND INDIANAPOLIS. WHILE RAIN HAS BEEN THE DOMINANT PTYPE...SOME REPORTS OF SNOW OR SLEET OCCURRING HAVE BEEN RECEIVED IN OUR FAR SOUTHERN COUNTIES WITH SOME SLUSHY LIGHT ACCUMULATIONS NOTED IN SOME AREAS. THIS AREA WILL CONTINUE TO PULL AWAY BY 12Z WEDS. FURTHER NORTH...FLOW IS BECOMING MORE N AND NW AND ALLOWING FOR EXPANDING DEVELOPMENT OF LAKE EFFECT SHOWERS ACROSS MUCH OF LAKE MI. THE GREATEST CONCENTRATION HAS BEEN RESIDING ALONG THE EASTERN HALF AND SOMEWHAT INLAND INTO WESTERN LWR MI. LAKE INDUCED INSTABILITY REMAINS IN THE MODERATE TO EXTREME CATEGORY (SFC-850 MB/SFC-700 MB DELTA T VALUES OF LOW 20S AND LOW 30S RESPECTIVELY) WITH LAKE BASED CAPES APPROACHING 1000 J/KG. AN OCCASIONAL REPORT OF SLEET/GRAUPEL HAVE COME IN ASSOCIATED WITH THE STRONGER SHOWERS. AS THIS SHOULD CONTINUE...HAVE ADDED MENTION OF SLEET IN CATEGORICAL AREAS. IN TERMS OF TIMING AND COVERAGE HRRR HAS A NICE HANDLE ON BOTH PRECIP TO THE SOUTH AND EVOLUTION OF LAKE EFFECT SHOWERS. EXPECTING A CHAOTIC PATTERN TO THE LAKE EFFECT SHOWERS INITIALLY AS SFC OBS INDICATING MESO LOW THAT WAS ADVERTISED ON HIGH RES MODELS PAST COUPLE OF DAYS HAS TAKEN SHAPE OVER THE SOUTHERN PART OF THE LAKE. THIS FEATURE WILL WORK SLOWLY SOUTH AND MOVE ONSHORE IN THE 9 TO 12Z WINDOW. HAVE EXPANDED CAT POPS FURTHER EAST INTO ALL OF BERRIEN AS WELL AS PART OF CASS AND ST JOE INDIANA COUNTIES TO COVER UPSTREAM TRENDS. CHANCES FOR SNOW/GRAUPEL WILL DECREASE AFTER 15Z AS TEMPS BEGIN TO WARM INTO THE 40S. FOR THIS AFTERNOON...HI RES MODELS SEEM TO LOWER OVERALL DEPTH OF MSTR BUT STILL LINGER A DECENT AMOUNT WHERE STRONGEST OMEGA RESIDES. IN ADDITION...INSTABILITY WILL REMAIN UNCHANGED. WHILE SOME CONCERN THAT COVERAGE COULD DIMINISH SOMEWHAT IN THE 19 TO 23Z RANGE WITH THIS DECREASE IN MSTR...WILL GO WITH INSTABILITY MAKING UP THE DIFFERENCE WITH HIGH LIKELY/LOW CAT POPS WARRANTED (AND EXPANDED SLIGHTLY TO BETTER REFLECT EXPECTED FLOW). NEXT WAVE OF INTEREST...PRESENTLY DIVING SE THROUGH THE DAKOTAS...WILL APPROACH LATER THIS AFTERNOON AND TONIGHT. TRACK OF THIS FEATURE WILL AGAIN BE TO THE SW OF THE AREA... TRACKING THROUGH WESTERN IOWA INTO SOUTHERN ILLINOIS. CLOUD COVER WILL INCREASE NORTHEAST OF THE FEATURE ACROSS THE AREA BUT PRECIP CHANCES LOOK TO BE CONFINED DOWNWIND OF LK MI AS NW FLOW WILL INCREASE...AND BOUNDARY LAYER MOISTURE WILL PICK UP ONCE AGAIN. INCREASED POPS SOMEWHAT TO HIGH END LIKELY FOR NOW BUT SUBSEQUENT INCREASE TO CAT POPS MAY BE NEEDED IN LATER FORECASTS. LOWS WILL DROP INTO THE LOW 30S IN MOST SPOTS AWAY FROM THE LAKE WHICH MAY RESULT IN AN GREATER CHANCE OF SNOW VS RAIN BUT GIVEN LAKE PROCESSES PRECIP MAY REMAIN MAINLY RAIN. WILL KEEP MIX MENTION FOR NOW. && .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 417 AM EDT WED OCT 23 2013 LARGE SCALE TROUGH EXPECTED TO REMAIN OVER THE GREAT LAKES THROUGH THE WEEKEND BEFORE PATTERN BEGINS TO RELOAD WITH RISING HEIGHTS AND MODERATING TEMPERATURES NEXT WEEK. LAKE EFFECT RAIN AND SNOW SHOWERS WILL BE PRIMARY CONCERN DURING THE BEGINNING OF THE LONG TERM PERIOD. WEAK SHORT WAVE AND SURFACE TROUGH TO PASS ACROSS THE AREA EARLY THU MORNING. THIS WILL HELP INCREASE SFC-700 DELTA T VALUES TO OVER 30 PROVIDING EXTREME INSTABILITY FROM LAKE MICHIGAN. LAKE INDUCED CAPE VALUES RISE TO OVER 800 J/KG WITH NEARLY UNIDIRECTIONAL NW FETCH. 1000-850MB RH REMAINS ABOVE 80 PERCENT SO SEE LITTLE REASON THAT LAKE EFFECT SHOWERS WILL NOT BE ONGOING. HAVE RAISED POPS TO CATEGORICAL ACROSS MI COUNTIES NEAR THE LAKE AND TAPERED FURTHER INLAND. PCPN TYPE WILL BE QUITE DIFFICULT AROUND THE LAKE AS MODIFIED BOUNDARY LAYER SHOULD KEEP PCPN MAINLY RAIN NEAR THE LAKE WITH A MIX OF RAIN AND SNOW INLAND WHERE THERMAL PROFILES MORE FAVORABLE FOR SNOW. HEAVIER SHOWERS TO BRING PERIODS OF MAINLY SNOW AND SLEET BUT FOR NOW HAVE KEPT FORECAST AS A RAIN/SNOW MIX GIVEN DIFFICULTY OF NAILING DOWN THESE MESOSCALE DETAILS AT THIS TIME RANGE. SOME MINOR SNOW ACCUMULATIONS ON GRASSY SURFACES WILL BE POSSIBLE AWAY FROM THE LAKE...ESPECIALLY THU NIGHT WITH DIURNAL COOLING AND CONTINUED EXTREME INSTABILITY AND FAVORABLE TRAJECTORIES. GIVEN THE INSTABILITY EXPECT SOME RATHER IMPRESSIVE RAINFALL TOTALS WHERE BANDS ARE PERSISTENT. LAKE EFFECT TO BEGIN WINDING DOWN LATER FRIDAY MORNING AS FLOW BACKS AHEAD OF NEXT APPROACHING SHORT WAVE AND INVERSION HEIGHTS LOWER WITH DECREASING MOISTURE. DELTA T VALUES REMAIN FAVORABLE FOR SOME LIGHTER SHOWERS CLOSER TO LAKE AND EVEN FRIDAY NIGHT WITH SOUTHWEST FLOW AFFECTING FAR NORTHERN BERRIEN COUNTY. ATMOSPHERE BECOMING RATHER DRY BY THIS TIME SO OPTED FOR JUST A SLIGHT CHANCE POP WITH SFC-850MB DELTA T VALUES STILL AROUND 20. A BRIEF MODERATION IN TEMPS EXPECTED SAT AHEAD OF NEXT SHORT WAVE AND COLD FRONT. TEMPS WILL STRONGLY DEPEND ON HOW FAST CLOUDS MOVE IN SATURDAY. SOUTHERN AREAS SHOULD SEE LOW TO MID 50S WHILE NORTHERN AREAS CLIMB TO NEAR 50. THIS CLIPPER WILL BRING ANOTHER BRIEF SHOT OF COLDER AIR AND A CHANCE FOR ADDITIONAL LAKE EFFECT RAIN SHOWERS. MEDIUM RANGE MODELS IN GOOD AGREEMENT ON LARGE SCALE PATTERN FOR EARLY NEXT WEEK AS WEST COAST ENERGY BEGINS TO CARVE OUT A NEW TROUGH OVER THE WESTERN CONUS. THIS ALLOWS HEIGHTS TO RISE OVER THE MIDWEST WITH MODERATING TEMPERATURES MONDAY AND TUESDAY. A COLD FRONT WILL SAG SOUTH AND BECOME NEARLY STATIONARY EITHER ACROSS OR JUST NORTH OF OUR AREA AS IT BECOMES PARALLEL TO MID LEVEL FLOW. THIS FRONT WILL BE FOCUS FOR SHOWERS MONDAY INTO TUESDAY AND EVEN WEDNESDAY OF NEXT WEEK. A LOT TO WATCH WITH THIS EVOLUTION AS WARM SECTOR WILL LIKELY BE RELATIVELY WARM FOR OCTOBER AND A NICE BAROCLINIC ZONE WILL SET NEAR OUR AREA. SURFACE WAVE DEVELOPMENT AROUND DAY 7 WILL HELP BACK WINDS AND STRONG 100 KNOT JET LOOKS TO RACE TOWARD THE AREA. KINEMATICS LOOK FAVORABLE FOR SEVERE WEATHER IN THE MIDWEST OR MID SOUTH BUT INSTABILITY REMAINS A BIG UNKNOWN. HOWEVER...CLIMATOLOGY FAVORS A SECONDARY SEVERE WEATHER PEAK IN OCTOBER FOR WEAK INSTABILITY/HIGH SHEAR SEVERE WEATHER EVENTS. CERTAINLY WORTH WATCHING NEXT SEVERAL DAYS IN MODEL EVOLUTION. PATTERN REMAINS QUITE ACTIVE GIVEN NUMEROUS PACIFIC/ASIAN CYCLONES OVER THE LAST FEW WEEKS WHICH HAVE HELPED AMPLIFY THE MID LEVEL FLOW AND DOWNSTREAM PATTERN OVER THE CONUS. LONGER RANGE OUTLOOK FOR DAY 7-10 ALSO LOOKS QUITE INTERESTING WITH WEST CONUS LOW EJECTION TOWARD THE AREA BY LATE NEXT WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 737 AM EDT WED OCT 23 2013 PATCHY DENSE FOG HAS DEVELOPED OVER NE INDIANA INCLUDING FWA TERMINAL. VSBYS EXPECTED TO IMPROVE THERE AROUND 1330Z AS MIXING STRENGTHENS. COLD AIR ALOFT AND CYCLONIC FLOW WILL PROMOTE STRATO CU ACROSS THE AREA AT LEAST THROUGH THIS EVE. CIGS SHOULD GENERALLY BE VFR EXCEPT OCNLY LOWER IN LAKE EFFECT SHOWERS AT SBN. FEW SHRA ALSO PSBL VCNTY OF FWA THIS AFTN BUT COVERAGE EXPECTED TO BE LESS IN NE INDIANA SO LEFT MENTION OUT OF TAFS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT FRIDAY FOR LMZ043-046. && $$ SYNOPSIS...FISHER SHORT TERM...FISHER LONG TERM...LASHLEY AVIATION...JT VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
524 AM MDT WED OCT 23 2013 .SHORT TERM...(TODAY THROUGH FRIDAY NIGHT) ISSUED AT 305 AM MDT WED OCT 23 2013 LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW STILL IN PLACE ACROSS PLAINS WITH LARGE SCALE TROUGH ACROSS THE EASTERN CONUS. MAIN STORM TRACK IS STILL OVER NORTHER PLAINS AND UPPER MISSISSIPPI VALLEY...WELL OUTSIDE OF OUR AREA OF CONCERN. AT THE SURFACE A BACKDOOR COLD FRONT HAS STALLED OVER OUR CWA...TO BE NEAR KGLD. NORTHEAST OF THIS FEATURE 10-12KFT CLOUD DECK ASSOCIATED WITH EMBEDDED ENERGY WITHIN MEAN UPPER FLOW IS MOVING ACROSS THE NORTHEASTERN PART OF OUR CWA. NW FLOW WILL SHIFT EAST WITH CONFLUENT PATTERN/LARGE SCALE SUBSIDENCE REMAINING IN PLACE THROUGH FRIDAY. QUASI-STATIONARY FRONT OVER THE CWA WILL SHIFT NORTHEAST TODAY AND THEN BACK TO THE WEST OF THE CWA TONIGHT...BEFORE LIFTING TO THE NORTH AGAIN BY FRIDAY. BREEZY CONDITIONS ARE ANTICIPATED DURING THE DAYTIME PERIODS TIED TO PEAK HEATING/MIXING. SURFACE HIGH PRESSURE BEGINS TO BUILD SOUTH TONIGHT BEHIND THIS FRONT WITH LIGHT EASTERLY FLOW AND INCREASING BL MOISTURE SUPPORTING POSSIBLE STRATUS/FOG. MODELS NEVER COMPLETELY SATURATE BOUNDARY LAYER...HOWEVER CONSIDERING THE PATTERN/CONCEPTUAL MODEL SUPPORTING FOG AND MET GUIDANCE SHOWING REDUCED VISIBILITIES I DECIDED TO ADD PATCHY FOG MENTION LATE FRIDAY NIGHT THROUGH THURSDAY MORNING. HIGHS WILL GENERALLY BE SEASONAL TODAY AND FRIDAY (HIGHS 60S TO NEAR 70F) WITH COOLER TEMPS THURSDAY AS A RESULT OF THE FRONT FURTHER WEST...WHEN AIR MASS OVER CWA WILL MAINLY SUPPORT HIGHS ONLY IN THE 50S. BY FRIDAY NIGHT A WEAK CUTOFF LOW WILL MOVE FROM THE FOUR CORNERS REGION INTO THE SOUTHERN PLAINS. CURRENT TRACK KEEPS MOISTURE AND BEST LARGE SCALE SUPPORT WELL SOUTH OF OUR CWA. WHILE THERE IS SOME ELEVATED INSTABILITY ACROSS SW KS THAT COULD SUPPORT A FEW SPRINKLES AS FAR NORTH AS WICHITA/GREELEY COUNTIES...CONFIDENCE IS IN CONDITIONS REMAINING DRY WITH THIS FEATURE FRIDAY NIGHT. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 305 AM MDT WED OCT 23 2013 WARM WEEKEND AHEAD OF A STRONG COLD FRONT EARLY NEXT WEEK WHICH WILL BRING THE CHANCE FOR WINTRY PRECIP AND COLD TEMPS. SATURDAY AND SUNDAY WILL BE MILD WITH WEAK RIDGING MOVING ACROSS THE CENTRAL HIGH PLAINS LATE SATURDAY. SUNDAY WILL BE QUITE WARM WITH HIGHS IN THE 70S DUE TO WARM AIR ADVECTION AND FULL SUNSHINE. FAIRLY HIGH CONFIDENCE EARLY NEXT WEEK A STRONG COLD FRONT WILL SURGE SOUTH THROUGH THE HIGH PLAINS BRINGING MUCH COLDER AIR AND CHANCES FOR PRECIP. MODEL DIFFERENCES ARE STILL FAIRLY LARGE EVEN WHEN COMPARING MODELS RUN-TO-RUN...WITH LEAST CONFIDENCE IN PRECIP AND TIMING. THE COLD IS A DIFFERENT STORY WITH ALL GLOBAL GUIDANCE SHOWING A SURGE OF COLD AIR MOVING SOUTH BY MID-WEEK NEXT WEEK...BUT AGAIN WITH TIMING DIFFERENCES. GENERALLY LEFT THE MODEL BLEND AS-IS BESIDES INCREASING SOME POPS SLIGHTLY. AT THIS POINT IT LOOKS LIKE THE FRONT WILL PUSH THROUGH LATE MONDAY WITH PRECIP BEGINNING AS SNOW...THEN POSSIBLY CHANGING TO RAIN/SNOW MIX ON TUESDAY AFTERNOON. DID NOT SPEND TO MUCH TIME NIT-PICKING TIMING AND PTYPE AT THIS TIME RANGE DUE TO COARSE TIME RESOLUTION OF GRIDS AT THIS RANGE....AND AT THIS POINT IT LOOKS LIKE THE PTYPES SHOULD BE STRAIGHTFORWARD /RAIN AND SNOW/. THE 00Z GFS IS A LITTLE CONCERNING WITH A WARM LAYER ALOFT TUESDAY...BUT GIVEN THE COMPLEXITY OF THE SET-UP AM NOT CONCERNED ABOUT IT JUST YET. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 524 AM MDT WED OCT 23 2013 VFR CONDITIONS WILL PERSIST THROUGH THIS EVENING AT BOTH TERMINALS. WITH LIGHT WINDS AND EASTERLY FLOW DEVELOPING BEHIND A COLD FRONT TONIGHT I WOULD EXPECT AN INCREASING CHANCE FOR FOG/STRATUS DEVELOPMENT. SO FAR MET GUIDANCE IS SHOWING THIS AT KGLD AROUND 12Z...HOWEVER THERE IS LITTLE INDICATION FROM OTHER GUIDANCE. I WENT AHEAD AND ADDED MVFR GROUP TO KGLD TAF FOR LATE TONIGHT...WITH LESS CONFIDENCE AT KMCK. WINDS WILL SHIFT TO THE NORTHWEST THIS AFTERNOON AND INCREASE WITH GUSTS GENERALLY IN THE 20-25KT RANGE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...JJM AVIATION...DR
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
809 AM EDT WED OCT 23 2013 .SYNOPSIS... A SERIES OF WEATHER DISTURBANCES WILL BRING THE FIRST SNOW FLAKES OF THE SEASON AND MUCH COLDER TEMPERATURES FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ANOTHER QUICK UPDATE AT 815AM AFTER RECEIVING A REPORT OF SNOW IN TERRA ALTA...ALTHOUGH SNOW IS NOT ACCUMULATING AT THIS TIME. NEEDED TO AT LEAST GET A MENTION OF SNOW IN THE RIDGES ABOVE 2500 FEET FOR THE MORNING HOURS. ONLY CHANGE MADE WITH THE 745AM UPDATE WAS TO SLIGHTLY BUMP UP POPS ALONG THE INTERSTATE 80 CORRIDOR DURING THE LATE MORNING AND EARLY AFTERNOON TIME PERIOD. A BAND OF PRECIPITATION IS CURRENTLY ALIGNED ALONG THE LAKE ERIE SHORELINE AND MOVING INLAND. LATEST RUNS OF THE HRRR AND RAP DEPICT THE BAND DISSIPATING AS IT MOVES INLAND...BUT PERHAPS LASTING SLIGHTLY LONGER THAN THE PREVIOUS FORECAST INDICATED. PREVIOUS DISCUSSION FOLLOWS. SHORTWAVE TROUGH WILL SWING THROUGH THE UPPER OHIO VALLEY THIS MORNING. A WEAK WAVE...AHEAD OF THE MAIN TROUGH...HAS SATURATED THE ATMOSPHERE ENOUGH TO ALLOW FOR SPRINKLES OR A BRIEF LIGHT SHOWER. TODAY`S FORECAST IS COMPLICATED DUE TO THE ABSENCE OF UPPER LEVEL SUPPORT. THE MAIN WAVE WITH THE SYSTEM WILL DIVE SOUTHEASTWARD ACROSS SOUTHERN OHIO...THEN THROUGH SOUTHERN WV... AND EVENTUALLY REACHING THE MID-ATLANTIC STATES BY LATE MORNING. MODELS CONTINUE TO SPREAD PRECIPITATION NORTHWARD ALONG THE TROUGH AXIS. WITH THE AXIS MOVING THROUGH QUICKLY...SHOWER ACTIVITY WOULD BE CONFINED TO THE MORNING HOURS. THE OTHER FLY IN THE OINTMENT IS WHAT IS OCCURRING IN THE UPPER LEVELS...VIEWABLE ON THE LATEST SAT PICS. MID AND HIGH CLOUDS ARE DECAYING OVER THE AREA...AS THE AFOREMENTIONED SHORTWAVE MOVES AWAY. THIS LOSS OF UPPER LEVEL MOISTURE WILL MAKE IT DIFFICULT FOR MUCH SHOWER ACTIVITY TO DEVELOP AND WE COULD END UP WITH A PERIOD OF DRIZZLE WITH THE TROUGH. WILL LEAVE IN CHC POPS FOR MOST LOCATIONS... NUDGING POPS INTO THE LIKELY CAT OVER THE FAR SOUTH. ONCE THE TROUGH EXITS...EXPECT A BREAK UNTIL THE CAA GETS GOING AND THE WINDS ALOFT VEER TO THE NORTHWEST. EARLIER THINKING WAS THAT SOME FLAKES COULD MIX IN WITH ANY ACTIVITY THIS MORNING. HOWEVER...WITH THE LOSS OF UPPER LEVEL CLOUDS AND ICE CRYSTALS...THIS IS BECOMING LESS LIKELY. THERE WOULD ONLY BE A SMALL WINDOW OF TIME WHERE THE ATMOSPHERE WOULD BE COLD ENOUGH TO SUPPORT SNOW. AS THE MORNING PROGRESS...THE LOWER LEVELS WILL WARM CREATING TOO LARGE A LAYER OF WARM AIR TO SUSTAIN FROZEN PRECIP. THIS SCENARIO SHOWS UP QUITE WELL ON THE LATEST FORECAST SOUNDINGS. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... FIRST PERIOD OF LES AND UP-SLOPE SNOW LOOKS TO BEGIN TONIGHT. CAA WILL CONTINUE AND THE 85H FLOW WILL VEER TO THE NORTHWEST. FORECAST SOUNDINGS OVER THE NORTH AND RIDGES SHOW A WELL SATURATED COLUMN INTO THE DENDRITIC GROWTH ZONE. LES BAND SHOULD GET GOING LATE THIS EVENING AND BECOME MORE ORGANIZED INTO EARLY THURSDAY MORNING. AT THE SAME TIME...UP-SLOPE SNOWS WILL PROCEED IN THE RIDGES TO THE SOUTHEAST OF PIT. IT REALLY APPEARS FROM THE SOUNDING AND PLAN VIEW DATA THAT SNOW SHOWERS WILL BE SPARSE ELSEWHERE. TEMPS OVERNIGHT WILL FALL OFF TOWARD THE FREEZING MARK. FORECASTING ACCUMULATIONS WILL BE TRICKY. EVEN THOUGH SURFACE TEMPS WILL FALL...MID OCTOBER GROUND IS STILL VERY WARM. BEST BET FOR SNOW STICKING TO THE GROUND WOULD BE ACROSS THE HIGHEST PEAKS OVER THE RIDGES. BY THURSDAY MORNING...FLOW WILL BECOME MORE WESTERLY...CAUSING THE SNOW SHOWER BAND OVER THE NORTH TO DRIFT FURTHER TO THE NORTH AND MOST LIKELY OUT OF MY FA. OVER THE RIDGES...INVERSION HEIGHTS WILL BEGIN TO FALL THURSDAY MORNING AS DRIER AIR ADVECTS IN. THIS SHOULD ALSO SHUT OFF THE SNOW SHOWERS IN THE HIGHER ELEVATIONS AS WELL. REST OF THE AREA LOOKS DRY AND COLD. NEXT SHORTWAVE TROUGH WILL SWING THROUGH THU NIGHT. EXPECT MORE SNOW SHOWERS TO DEVELOP LATE THU NIGHT. THIS MAY BE THE BEST TIME PERIOD FOR MORE WIDESPREAD SNOW SHOWERS. SOUNDINGS ARE SHOWING ATMOSPHERE SATURATING INTO THE DENDRITIC GROWTH ZONE AS FAR SOUTH AS PIT. UPPER LEVEL TEMPS WILL BE PLENTY COLD ENOUGH TO SUPPORT SNOW AS WILL LOW LEVEL THICKNESSES. ITS NOT OUT OF THE QUESTION THAT A WHITENING OF GRASSY AREAS IS POSSIBLE FROM PIT NORTHWARD...WITH MINOR ACCUMULATIONS OVER THE I-80 CORRIDOR AND RIDGES. SNOW SHOWER ACTIVITY WILL EVENTUALLY BE CONFINED TO THE I-80 CORRIDOR AS WINDS TURN TO THE WEST. WELL BELOW NORMAL TEMPS AGAIN FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... HIGH PRES IS EXPD TO BLD IN FRI NGT INTO ERLY SAT. ANOTHER QUICK MOVG CDFNT IS PROGGED TO CROSS THE GT LKS SAT EVE BRINGING ANOTHER CHC OF MAINLY RA SHWRS...ESP N PIT WHERE DEEPER MOISTURE IS EXPD. HIGH PRES IS EXPD TO BLD IN LTR SUN AND MON BEFORE SHWR CHCS RTN WITH THE NEXT CDFNT PROGGED FOR TUE. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS WILL CONTINUE TO PREVAIL UNTIL SHOWERS ASSOCIATED WITH A SHORTWAVE REACH THE REGION THROUGH THE MORNING HOURS. EXPECT MAINLY MVFR CONDITIONS...ALTHOUGH IFR CONDITIONS WILL BE POSSIBLE AS SHORT WAVE PASSES AND SOME UPSLOPE/LINGERING LOW LEVEL MOISTURE AND LIFT MAY BRING ADDITIONAL DRIZZLE AROUND KLBE/KMGW. IN ADDITION...THERE IS A THE POTENTIAL FOR A MIX OF RAIN AND SNOW...ESPECIALLY NORTH...WHICH MAY YIELD ADDITIONAL DOWNWARD PRESSURE ON VISIBILITIES THROUGH THE MORNING HOURS WHERE IT OCCURS. MODEL SOUNDINGS SUGGEST A GRADUAL IMPROVEMENT BY LATE AFTERNOON...ALTHOUGH NORTHWEST FLOW WILL KEEP LOW-END VFR/MVFR STRATOCU ACROSS THE REGION EVERYWHERE THROUGH THE PERIOD. WITH THE SHORTWAVES DEPARTURE...NORTHWESTERLY WINDS OVER 10KTS WITH GUSTS TO 15-20KTS WILL BE POSSIBLE. OUTLOOK.../THURSDAY THROUGH SUNDAY/... OCNL RSTRNS ARE PSBL IN RA/SN SHWRS THRU FRI AS UPR LVL DISTURBANCES CROSS THE GT LKS AND OH VLY RGN. RSTRNS ARE PSBL AGAIN SAT AFTN INTO SUN ESP N OF PIT WITH THE PASSAGE OF A CDFNT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
747 AM EDT WED OCT 23 2013 .SYNOPSIS... A SERIES OF WEATHER DISTURBANCES WILL BRING THE FIRST SNOW FLAKES OF THE SEASON AND MUCH COLDER TEMPERATURES FOR THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ONLY CHANGE MADE WITH THE 745AM UPDATE WAS TO SLIGHTLY BUMP UP POPS ALONG THE INTERSTATE 80 CORRIDOR DURING THE LATE MORNING AND EARLY AFTERNOON TIME PERIOD. A BAND OF PRECIPITATION IS CURRENTLY ALIGNED ALONG THE LAKE ERIE SHORELINE AND MOVING INLAND. LATEST RUNS OF THE HRRR AND RAP DEPICT THE BAND DISSIPATING AS IT MOVES INLAND...BUT PERHAPS LASTING SLIGHTLY LONGER THAN THE PREVIOUS FORECAST INDICATED. PREVIOUS DISCUSSION FOLLOWS. SHORTWAVE TROUGH WILL SWING THROUGH THE UPPER OHIO VALLEY THIS MORNING. A WEAK WAVE...AHEAD OF THE MAIN TROUGH...HAS SATURATED THE ATMOSPHERE ENOUGH TO ALLOW FOR SPRINKLES OR A BRIEF LIGHT SHOWER. TODAY`S FORECAST IS COMPLICATED DUE TO THE ABSENCE OF UPPER LEVEL SUPPORT. THE MAIN WAVE WITH THE SYSTEM WILL DIVE SOUTHEASTWARD ACROSS SOUTHERN OHIO...THEN THROUGH SOUTHERN WV... AND EVENTUALLY REACHING THE MID-ATLANTIC STATES BY LATE MORNING. MODELS CONTINUE TO SPREAD PRECIPITATION NORTHWARD ALONG THE TROUGH AXIS. WITH THE AXIS MOVING THROUGH QUICKLY...SHOWER ACTIVITY WOULD BE CONFINED TO THE MORNING HOURS. THE OTHER FLY IN THE OINTMENT IS WHAT IS OCCURRING IN THE UPPER LEVELS...VIEWABLE ON THE LATEST SAT PICS. MID AND HIGH CLOUDS ARE DECAYING OVER THE AREA...AS THE AFOREMENTIONED SHORTWAVE MOVES AWAY. THIS LOSS OF UPPER LEVEL MOISTURE WILL MAKE IT DIFFICULT FOR MUCH SHOWER ACTIVITY TO DEVELOP AND WE COULD END UP WITH A PERIOD OF DRIZZLE WITH THE TROUGH. WILL LEAVE IN CHC POPS FOR MOST LOCATIONS... NUDGING POPS INTO THE LIKELY CAT OVER THE FAR SOUTH. ONCE THE TROUGH EXITS...EXPECT A BREAK UNTIL THE CAA GETS GOING AND THE WINDS ALOFT VEER TO THE NORTHWEST. EARLIER THINKING WAS THAT SOME FLAKES COULD MIX IN WITH ANY ACTIVITY THIS MORNING. HOWEVER...WITH THE LOSS OF UPPER LEVEL CLOUDS AND ICE CRYSTALS...THIS IS BECOMING LESS LIKELY. THERE WOULD ONLY BE A SMALL WINDOW OF TIME WHERE THE ATMOSPHERE WOULD BE COLD ENOUGH TO SUPPORT SNOW. AS THE MORNING PROGRESS...THE LOWER LEVELS WILL WARM CREATING TOO LARGE A LAYER OF WARM AIR TO SUSTAIN FROZEN PRECIP. THIS SCENARIO SHOWS UP QUITE WELL ON THE LATEST FORECAST SOUNDINGS. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... FIRST PERIOD OF LES AND UP-SLOPE SNOW LOOKS TO BEGIN TONIGHT. CAA WILL CONTINUE AND THE 85H FLOW WILL VEER TO THE NORTHWEST. FORECAST SOUNDINGS OVER THE NORTH AND RIDGES SHOW A WELL SATURATED COLUMN INTO THE DENDRITIC GROWTH ZONE. LES BAND SHOULD GET GOING LATE THIS EVENING AND BECOME MORE ORGANIZED INTO EARLY THURSDAY MORNING. AT THE SAME TIME...UP-SLOPE SNOWS WILL PROCEED IN THE RIDGES TO THE SOUTHEAST OF PIT. IT REALLY APPEARS FROM THE SOUNDING AND PLAN VIEW DATA THAT SNOW SHOWERS WILL BE SPARSE ELSEWHERE. TEMPS OVERNIGHT WILL FALL OFF TOWARD THE FREEZING MARK. FORECASTING ACCUMULATIONS WILL BE TRICKY. EVEN THOUGH SURFACE TEMPS WILL FALL...MID OCTOBER GROUND IS STILL VERY WARM. BEST BET FOR SNOW STICKING TO THE GROUND WOULD BE ACROSS THE HIGHEST PEAKS OVER THE RIDGES. BY THURSDAY MORNING...FLOW WILL BECOME MORE WESTERLY...CAUSING THE SNOW SHOWER BAND OVER THE NORTH TO DRIFT FURTHER TO THE NORTH AND MOST LIKELY OUT OF MY FA. OVER THE RIDGES...INVERSION HEIGHTS WILL BEGIN TO FALL THURSDAY MORNING AS DRIER AIR ADVECTS IN. THIS SHOULD ALSO SHUT OFF THE SNOW SHOWERS IN THE HIGHER ELEVATIONS AS WELL. REST OF THE AREA LOOKS DRY AND COLD. NEXT SHORTWAVE TROUGH WILL SWING THROUGH THU NIGHT. EXPECT MORE SNOW SHOWERS TO DEVELOP LATE THU NIGHT. THIS MAY BE THE BEST TIME PERIOD FOR MORE WIDESPREAD SNOW SHOWERS. SOUNDINGS ARE SHOWING ATMOSPHERE SATURATING INTO THE DENDRITIC GROWTH ZONE AS FAR SOUTH AS PIT. UPPER LEVEL TEMPS WILL BE PLENTY COLD ENOUGH TO SUPPORT SNOW AS WILL LOW LEVEL THICKNESSES. ITS NOT OUT OF THE QUESTION THAT A WHITENING OF GRASSY AREAS IS POSSIBLE FROM PIT NORTHWARD...WITH MINOR ACCUMULATIONS OVER THE I-80 CORRIDOR AND RIDGES. SNOW SHOWER ACTIVITY WILL EVENTUALLY BE CONFINED TO THE I-80 CORRIDOR AS WINDS TURN TO THE WEST. WELL BELOW NORMAL TEMPS AGAIN FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... HIGH PRES IS EXPD TO BLD IN FRI NGT INTO ERLY SAT. ANOTHER QUICK MOVG CDFNT IS PROGGED TO CROSS THE GT LKS SAT EVE BRINGING ANOTHER CHC OF MAINLY RA SHWRS...ESP N PIT WHERE DEEPER MOISTURE IS EXPD. HIGH PRES IS EXPD TO BLD IN LTR SUN AND MON BEFORE SHWR CHCS RTN WITH THE NEXT CDFNT PROGGED FOR TUE. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS WILL CONTINUE TO PREVAIL UNTIL SHOWERS ASSOCIATED WITH A SHORTWAVE REACH THE REGION THROUGH THE MORNING HOURS. EXPECT MAINLY MVFR CONDITIONS...ALTHOUGH IFR CONDITIONS WILL BE POSSIBLE AS SHORT WAVE PASSES AND SOME UPSLOPE/LINGERING LOW LEVEL MOISTURE AND LIFT MAY BRING ADDITIONAL DRIZZLE AROUND KLBE/KMGW. IN ADDITION...THERE IS A THE POTENTIAL FOR A MIX OF RAIN AND SNOW...ESPECIALLY NORTH...WHICH MAY YIELD ADDITIONAL DOWNWARD PRESSURE ON VISIBILITIES THROUGH THE MORNING HOURS WHERE IT OCCURS. MODEL SOUNDINGS SUGGEST A GRADUAL IMPROVEMENT BY LATE AFTERNOON...ALTHOUGH NORTHWEST FLOW WILL KEEP LOW-END VFR/MVFR STRATOCU ACROSS THE REGION EVERYWHERE THROUGH THE PERIOD. WITH THE SHORTWAVES DEPARTURE...NORTHWESTERLY WINDS OVER 10KTS WITH GUSTS TO 15-20KTS WILL BE POSSIBLE. OUTLOOK.../THURSDAY THROUGH SUNDAY/... OCNL RSTRNS ARE PSBL IN RA/SN SHWRS THRU FRI AS UPR LVL DISTURBANCES CROSS THE GT LKS AND OH VLY RGN. RSTRNS ARE PSBL AGAIN SAT AFTN INTO SUN ESP N OF PIT WITH THE PASSAGE OF A CDFNT. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
749 AM EDT WED OCT 23 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 439 AM EDT WED OCT 23 2013 THE CWA IS UNDER THE WESTERN SIDE OF AN UPPER TROUGH COVERING THE THE GREAT LAKES REGION. THIS TROUGH IS ALLOWING COLD AIR TO SURGE SOUTH OVER THE AREA AND LEAD TO BELOW NORMAL TEMPERATURES OVER THE LAST COUPLE OF DAYS. AT THE SURFACE...A NEARLY STATIONARY LOW EAST OF JAMES BAY AND A HIGH PRESSURE RIDGE STRETCHING FROM THE CANADIAN PRAIRIES INTO THE NORTHERN PLAINS WILL CONTINUE TO PRODUCE NORTHWESTERLY FLOW OVER THE AREA OVER THE NEXT 24-36HRS. SNOW SHOWERS ACROSS THE AREA ARE FAIRLY DISORGANIZED AND BLOTCHY EARLY THIS MORNING AS WINDS HAVE BEEN BOUNCING AROUND DURING THE OVERNIGHT HOURS (DUE TO LAND BREEZES AND WEAK SURFACE TROUGH STRETCHING ACROSS THE WESTERN LAKE). THIS DISORGANIZATION IS ALSO LIKELY DUE TO MODELS SHOWING DEEPER MOISTURE TO BE LACKING OVER MUCH OF THE AREA AT THIS TIME (EVEN THOUGH 850MB TEMPS ANALYZED ON THE RAP ARE -8C). THE LAST HOUR OR SO HAS SEEN A SLIGHT INCREASE IN COVERAGE AND INTENSITY...LARGELY DUE TO THE POCKET OF MOISTURE THAT IS SLIDING OUT OF NORTHEAST MINNESOTA AND ASSOCIATED WITH WEAK SHORTWAVE ENERGY. THIS TREND WILL PROBABLY CONTINUE THROUGH THE NEXT COUPLE HOURS AND HAVE TRENDED POPS UP (FROM CURRENT SCATTERED COVERAGE) THROUGH THE MID MORNING HOURS. STRONGEST SHOWERS WILL LIKELY BE EAST OF MUNISING AND POTENTIALLY FOCUSED IN GOGEBIC/ONTONAGON COUNTIES WITH WINDS TRYING TO BACK SLIGHTLY AHEAD OF THE WEAK LAKE INDUCED SURFACE TROUGH OVER THE WESTERN LAKE EARLY THIS MORNING. HIGH RESOLUTION MODELS PICKING UP ON THIS IDEA IN THEIR PRECIP/REFLECTIVITY FIELDS AND LEADS TO INCREASED CONFIDENCE. ONCE DAYTIME HEATING TAKES HOLD AND POCKET OF DRIER AIR ALONG THE MINNESOTA/CANADA BORDER DROPS OVER THE AREA...THINK THE SHOWERS WILL DIMINISH SOME...ESPECIALLY OVER THE WEST WHERE THE FETCH IS SHORTER. ONE OTHER ITEM FOR THIS AFTERNOON...HELD ONTO SOME POPS OVER THE SOUTH CENTRAL...EVEN THOUGH THAT ISN/T A FAVORABLE LOCATION FOR LAKE EFFECT. FELT HAVING SLIGHT CHANCES WAS REASONABLE WITH THE MOISTURE AVAILABLE AND STEEPENING LAPSE RATES (SFC-850MB VALUES AROUND 9C/KM) WITH THE COLD AIR ALOFT. THIS SHOULD BE ENOUGH FOR SOME CONVECTIVE CLOUD DEVELOPMENT AND MAYBE A FEW SHOWERS WITH THE INCREASING MOISTURE. THAT POCKET OF DRIER AIR WILL DEPART AS A SHORTWAVE DROPS SOUTH FROM ONTARIO THIS AFTERNOON AND EVENING. THIS BRINGS ADDITIONAL LOW-MID LEVEL MOISTURE WITH IT AND WILL AID THE LAKE EFFECT SHOWERS THAT WILL BE ONGOING. IT WILL ALSO BRING ABOUT A SLIGHT WIND SHIFT TO MORE OF A NORTH-NORTHWEST DIRECTION AND PUSH THE ONGOING LAKE EFFECT SHOWERS TO THE WEST. BEST MOISTURE IS OVER THE EASTERN CWA...SO WOULD EXPECT THE STRONGEST SHOWERS THERE WITH THE GREATEST FETCH. MODELS ARE INDICATING THE WINDS SHIFT AIDING A DOMINATE BAND OVER THE EAST DURING THE EVENING (INITIALLY OVER FAR EASTERN LAKE SUPERIOR AND THEN SHIFTING SOUTHWEST TOWARDS GRAND MARAIS) WHICH WILL BE ASSISTED BY MOISTENING OFF LAKE NIPIGON. ONE NEGATIVE WITH THIS SHORTWAVE IS THAT IT DOES PULL SLIGHTLY WARMER 850MB TEMPS OVER THE AREA TONIGHT...RISING SLIGHTLY FROM -8C TODAY TO -6/-7C TONIGHT OVER THE EAST. THIS LEADS TO INCREASING LOW LEVEL TEMPS AND RISING WETBULB ZERO VALUES. 00Z NAM/GFS BUFKIT SOUNDINGS FOR KERY SHOW WETBULB ZERO VALUES RISING TO ALMOST 1.5KFT BY DAYBREAK...WHICH WOULD BE PRETTY MUCH RAIN. ALSO...MUNISING STAYED RIGHT AROUND 41 DEGREES EARLY THIS MORNING UNTIL THE LAND BREEZE KICKED IN AND SHIFTED THE WINDS TO THE SOUTHWEST (TEMP DROPPED TO 36 DEGREES). SINCE THE GRADIENT SHOULD BE TIGHTER TONIGHT...THINK THAT WILL KEEP TEMPS UP RIGHT ALONG THE SHORELINE. THEREFORE...AFTER SNOW DURING THE DAY...HAVE TRENDED TOWARDS A MIX OF RAIN/SNOW EAST OF A LINE FROM MUNISING TO MANISTIQUE. AS FOR SNOW AMOUNTS...THE RAIN/SNOW MIX CREATES UNCERTAINTY ALONG WITH SNOW RATIOS. HAVE KEPT SNOW RATIOS LOWER...TOWARDS 10-1...SINCE THE BEST FORCING CONTINUES TO BE BELOW THE DGZ AND ONLY THE TOP OF THE CLOUD IS WITHIN THE DGZ. AS WAS SEEN TODAY...THERE WILL PROBABLY BE PERIODS OF FLAKES AND ALSO SNOW GRAINS/PELLETS IN THE STRONGER SHOWERS DUE TO THE STRONG LIFT OF SUPER COOLED WATER RUNNING INTO THE SMALLER FLAKES ALOFT. FOR EXAMPLE...TODAY AT OUR OFFICE WE HAD 0.53 INCH OF LIQUID BUT THE SNOWFALL TOTAL WAS 2.2 INCHES. THUS...WONDERING IF THE CURRENT 10-1 FORECAST IS A LITTLE TOO HIGH OVER THE EAST AND MAY BE CLOSER TO A 7/8 TO 1. AS FOR SNOWFALL TOTALS...KEPT AMOUNTS AROUND AN INCH IN THE NW SNOW BELTS FOR TODAY (WITH LOCALIZED HIGHER AMOUNTS NEAR IRONWOOD AND THE PORKIES). THEN FOR TONIGHT...HAVE A GENERAL 1-3IN FOR THE SAME LOCATIONS...BUT LESSER AMOUNTS WHERE THE RAIN/SNOW MIX IS. SOME CONCERN FOR NEAR ADVISORY LEVEL SNOWFALL TONIGHT OVER THE EAST WITH THE DOMINATE BAND. BUT WITH THE UNCERTAINTY ON SNOW TYPE (FLAKE VS PELLET) AND ALSO SOME RAIN MIXING IN NEAR THE SHORELINE...DIDN/T HAVE ENOUGH CONFIDENCE TO ISSUE ONE FOR ALGER COUNTY AREA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 503 AM EDT WED OCT 23 2013 A BLOCKING RIDGE FROM THE ERN PACIFIC INTO WEST COAST WILL KEEP THE BROAD DOWNSTREAM TROUGH IN PLACE OVER THE CNTRL AND ERN CONUS THROUGH THE FCST PERIOD WITH CONTINUED BELOW NORMAL TEMPERATURES. SHORTWAVE TROUGHS IN THE NW FLOW THROUGH THE UPPER GREAT LAKES WILL SUPPORT PERIODS OF INCREASED LAKE EFFECT PCPN. THURSDAY...WITH 850 MB TEMPS AROUND -6C TO -7C AND 700 MB TEMPS AROUND -13C...INSTABILITY WILL REMAIN HIGH ENOUGH TO KEEP LAKE EFFECT PCPN GOING FOR LOCATIONS FAVORED BY NW FLOW. THE HIGHER RES MODELS INDICATED THAT A MORE DOMINANT BAND ORIGINATING OFF OF LAKE NIPIGON MAY DEVELOP THAT WOULD AFFECT THE AREA FROM NEAR MUNISING AND PICTURED ROCKS TO MANISTIQUE. EVEN THOUGH LOCAL QPF VALUES MAY APPROACH A QUARTER INCH...THE LONG FETCH ACROSS THE RELATIVELY WARM LAKE MAY BRING ENOUGH MARINE INFLUENCE (MODEL WET-BULB ZERO HEIGHTS 1000-1500 FT) TO BRING MAINLY RAIN NEAR THE SHORE AND A RAIN/SNOW/GRAUPEL MIX FARTHER INLAND. SNOW/WATER RATIOS ARE LIKELY TO BE LOW AS THE GREATEST UPWARD MOTION IS EXPECTED WELL BELOW THE 8K-10K FT DGZ. SNOW SHOWERS WILL ALSO CONTINUE INTO WRN UPPER MI BUT WITH SNOWFALL AMOUNTS AT OR BELOW AN INCH GIVEN THE SHORTER FETCH AND APPROACH OF MORE ACYC FLOW WITH THE RIDGE MOVING INTO THE UPPER MS VALLEY. THU NIGHT...WITH A WEAKER WIND FIELD...LAKE INDUCED TROUGHING WILL HELP TO KEEP THE FOCUS OF LAKE EFFECT PCPN FROM NEAR MUNISING INTO NW SCHOOLCRAFT COUNTY. LOW LEVEL TEMPS WILL REMAIN WARM ENOUGH TO SUPPORT A RAIN/SNOW MIX WHICH SHOULD LIMIT SNOW ACCUMULATIONS TO AN INCH OR LESS. OVER THE WEST...SNOW SHOWERS WILL BECOME SCATTERED AND DIMINISH AS INVERSION HEIGHT DROP AND DRIER AIR EDGES IN. FRI INTO SAT...THE GFS/ECMWF WERE IN GOOD AGREEMENT WITH THE CLIPPER SHORTWAVE TROUGH AND SFC LOW MOVING THROUGH THE NRN GREAT LAKES. THE GREATEST 285K-295K ISENTROPIC LIFT AND ASSOCIATED PCPN BAND AHEAD OF THE LOW IS EXPECTED TO MOVE THROUGH THE EAST HALF OF LAKE SUPERIOR AND UPPER MICHIGAN FRI NIGHT. CAA BEHIND THE LOW DROPPING 850 MB TEMPS BACK TO -7C WILL BRING ANOTHER ROUND OF LAKE EFFECT PCPN FOR NW FLOW FAVORED LOCATIONS FROM SAT AFTERNOON INTO SAT NIGHT. LOW LEVEL TEMPS WILL BE WARM ENOUGH FOR A RAIN/SNOW MIX...EXCEPT OVER THE HIGHER TERRAIN OF THE WEST HALF. SUN-TUE...MODEL DIFFERENCES BECOME MORE SIGNIFICANT. THE ECMWF IS FASTER WITH THE NEXT SHORTWAVE AND PUSHES LOWER HEIGHTS AND CONFLUENCE ZONE FARTHER SOUTH COMPARED TO THE GFS/GEM. SO...FCST CONFIDENCE IN LOCATION OF EVOLUTION OF PCPN CHANCES ASSOCIATED WITH THE DEVELOPING 800-600 FGEN ZONE MON AND AREA OF WAA ISENTROPIC LIFT INTO TUE IS LOW. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 748 AM EDT WED OCT 23 2013 NORTHWEST FLOW LAKE EFFECT WILL BE AFFECTING UPPER MICHIGAN OVER THE NEXT 24HRS. EXPECT CONDITIONS TO TRANSITION TO MVFR AT KIWD/KCMX THIS MORNING AS LAKE EFFECT SHOWERS EXPAND OVER WESTERN UPPER MICHIGAN. AS DRIER AIR ALOFT SLIDES IN TOWARDS MID DAY...EXPECT CONDITIONS TO IMPROVE TO VFR FOR A FEW HOURS. THEN...A SHORTWAVE AND DEEPER MOISTURE WILL SLIDE SOUTH ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND TONIGHT...LEADING TO DETERIORATING CONDITIONS FOR THE SECOND HALF OF THE TAF PERIOD. EXPECT VISIBILITIES TO FALL TONIGHT TO AT LEAST IFR AT KIWD AND POTENTIALLY KCMX. AT KSAW...NORTHWEST WINDS AREN/T OVERLY FAVORABLE...BUT EXPECT A BRIEF PERIOD OF MVFR CEILINGS LATE THIS MORNING BEFORE TRANSITIONING BACK TO VFR. AS THE SHORTWAVE AND DEEPER MOISTURE ARRIVES TONIGHT...EXPECT CEILINGS TO FALL TO MVFR AND MAYBE EVEN IFR. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 439 AM EDT WED OCT 23 2013 WITH THE UPPER GREAT LAKES BETWEEN A LOW OVER WESTERN QUEBEC AND A HIGH PRESSURE RIDGE STRETCHING FROM THE CANADIAN PRAIRIES AND INTO THE NORTHERN PLAINS...EXPECT PERSISTENT NORTHWEST WINDS OF 15-25KTS THROUGH THURSDAY. THERE COULD BE SOME GUSTS TO 30KTS OVER THE EAST TONIGHT AS THE PRESSURE GRADIENT TIGHTENS SLIGHTLY. WINDS ARE EXPECTED TO DIMINISH AND BACK ON THURSDAY NIGHT AND FRIDAY...AS A HIGH PRESSURE RIDGE MOVES THROUGH THE UPPER GREAT LAKES. A CLIPPER SYSTEM WILL DIVE SOUTHEAST OUT OF CANADA ON FRIDAY NIGHT AND MOVE ACROSS EASTERN LAKE SUPERIOR. THIS WILL ONCE AGAIN SHIFT WINDS BACK TO THE NORTHWEST UP TO 30KTS FOR SATURDAY AND SATURDAY NIGHT...ESPECIALLY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL MOVE BACK INTO THE GREAT LAKES FOR SUNDAY...DECREASING THE WINDS BELOW 20KTS. FINALLY...WILL CONTINUE TO MENTION A SLIGHT CHANCE FOR WATERSPOUTS OVER THE SOUTHEAST PART OF LAKE SUPERIOR FOR THIS AFTERNOON INTO TONIGHT. WATERSPOUT NOMOGRAM INDICATES BORDERLINE POTENTIAL...BUT WITH STRONGER LAKE EFFECT SHOWERS OCCURRING DURING THAT TIME...FELT IT WAS WARRENTED TO KEEP IN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...JLB AVIATION...SRF MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
546 AM CDT WED OCT 23 2013 .UPDATE... ISSUED AT 547 AM CDT WED OCT 23 2013 UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 255 AM CDT WED OCT 23 2013 CURRENT WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES LOOK QUITE FAMILIAR... GIVEN THAT THE LARGE SCALE PATTERN HASN/T CHANGED MUCH IN THE PAST SEVERAL DAYS. LONGWAVE TROUGH REMAINS OVER THE EASTERN HALF OF THE CONTINENT... WITH A LONGWAVE RIDGE CENTERED ALONG THE WESTERN COAST. WE REMAIN IN PRIMARILY DRY AND COOL NORTHWEST UPPER FLOW. HOWEVER... SOME FLURRIES AND A FEW SNOW SHOWERS ARE EVIDENT IN RADAR IMAGERY AND SURFACE OBS GIVEN SOME WEAK FORCING FROM CHANNELED VORTICITY ADVECTION COMBINED WITH GOOD LAPSE RATES AND JUST ENOUGH MOISTURE TO GET THINGS GOING. THESE CONDITIONS WON/T CHANGE MUCH TODAY... SO THE EASTERN/NORTHERN PORTION OF THE AREA SHOULD CONTINUE TO SEE SOME FLURRIES AND THE ODD SNOW SHOWER THROUGH THE DAY... PERHAPS PICKING UP SOME DURING THE AFTERNOON AS LAPSE RATES STEEPEN IN THE BOUNDARY LAYER. MOSTLY CLOUDY CONDITIONS WILL PERSIST AS WELL... ALTHOUGH SOME BREAKS OF SUNSHINE WILL ONCE AGAIN OCCUR. THE FAR SOUTHWEST PORTION OF THE CWFA WILL HAVE A DEJA VU MOMENT... WITH A VERY SIMILAR SYSTEM TO YESTERDAY PASSING BY TO ITS WEST AND SOUTH THIS MORNING AND EARLY AFTERNOON. GIVEN WHERE THE PCPN IS ALREADY TRYING TO DEVELOP OVER THE DAKOTAS... ITS TRAJECTORY LOOKS TO ONCE AGAIN LARGELY MISS OUR FORECAST AREA... ALTHOUGH SOME FLURRIES OR BRIEF LIGHT SNOW COULD SNEAK ACROSS LOCATIONS SOUTHWEST OF THE MINNESOTA VALLEY. THE HRRR... HOPWRF... AND MPXWRF ALL TELL SIMILAR TALES WITH THIS AREA OF PCPN... KEEPING ANYTHING MEANINGFUL OUT OF OUR AREA. KEPT SOME LOW POPS FOR LIGHT SNOW IN THE FAR SOUTHWEST... WITH A MENTION OF FLURRIES BORDERING ITS NORTHEAST EDGE UP TOWARD THE MINNESOTA RIVER. SOME SURFACE RIDGING LOOKS LIKE IT WILL TRY TO BUILD INTO THE AREA TONIGHT... SO ALLOWED THE ISOLATED SNOW SHOWERS OVER THE NORTHEAST FORECAST AREA TO WIND DOWN IN THE EARLY EVENING. HOWEVER... WITH THE MID-LEVEL COLD POOL STILL OVER THE AREA AND SOME CONTINUED WEAK FORCING... WOULDN/T RULE OUT THE NEED FOR LATER FORECASTS TO THROW A MENTION OF SNOW SHOWERS/FLURRIES BACK INTO THE FORECAST FOR THE ENTIRE NIGHT. REGARDLESS... ANYTHING THAT OCCURS SHOULDN/T BE OF MUCH SIGNIFICANT... WITH ONLY THE HEAVIEST OF SNOW SHOWERS PERHAPS WHITENING THE GROUND. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 255 AM CDT WED OCT 23 2013 THE WESTERN PERIPHERY OF THE EASTERN CONUS MID/UPPER TROUGH HAS ONE LAST DAY OF INFLUENCE OVER THE LOCAL WEATHER ON THURSDAY...WITH STEEPENING LAPSE RATES INDICATING THE POTENTIAL FOR A FEW LIGHT SHOWERS/SPRINKLES...POSSIBLY IN THE FROZEN FORM FOR AREAS NORTH OF INTERSTATE 94 DURING THE MORNING. TEMPS WILL STILL BE ON THE CHILLY SIDE...WITH HIGHS IN THE UPPER 30S TO LOWER 40S EXPECTED...AND LOWS DIPPING INTO THE MID AND UPPER 20S BY DAYBREAK FRIDAY. FRIDAY APPEARS DRY AND A TAD WARMER...AS SOUTHWEST LLVL FLOW DEVELOPS AHEAD OF THE NEXT NORTHERN STREAM WAVE. THE ASSOCIATED TROUGH PASSES ON FRIDAY NIGHT...WITH THE MAIN RESULT BEING A SHIFT TO BRISK NORTHWEST WINDS FOR SATURDAY. WITH THE PRIMARY FORCING RELATED TO THE WAVE PASSING OVER THE GREAT LAKES REGION...NO PRECIPITATION IS EXPECTED FOR THE MAJORITY OF THE AREA...ALTHOUGH A FEW FLURRIES OR LIGHT SNOW/RAIN SHOWERS APPEAR POSSIBLE OVER WEST CENTRAL WI ON FRIDAY NIGHT AND SATURDAY. TEMPERATURES RECOVER A BIT FOR SUNDAY...ALTHOUGH ONLY AREAS ALONG/SOUTH OF THE MN RIVER VALLEY ARE EXPECTED TO ESCAPE THE 40S. DURING THE BEGINNING OF NEXT WEEK...AN UPPER TROUGH IS CARVED OUT FROM THE FOUR CORNERS REGION ACROSS THE CENTRAL/NORTHERN PLAINS. WHILE THERE ARE SOME AMPLITUDE DIFFERENCES BETWEEN THE GFS AND ECMWF...BOTH MODELS INDICATE AT LEAST A SLIGHT POTENTIAL FOR SHOWERS IN THE MONDAY-TUESDAY TIME FRAME. HAVE INCLUDED 20-30 POPS FOR BOTH DAYS. THE PRECIP TYPE WILL BE UNCERTAIN UNTIL THE OTHER LARGER DETAILS ARE WORKED OUT...ALTHOUGH THERMAL PROFILES ARE SUPPORTIVE OF RAIN-SNOW. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 547 AM CDT WED OCT 23 2013 THE STATUS QUO LOOKS TO BE THE THEME THROUGH ANOTHER FORECAST PERIOD. CONTINUED NORTHWEST UPPER LEVEL FLOW WILL CONTINUE TO BRING SIMILAR CONDITIONS INTO THE AREA... WITH PERIODIC WEAK SHORTWAVES AND GOOD LOW LEVEL LAPSE RATES WORKING TO KEEP PLENTY OF VFR CEILINGS IN PLACE ALONG WITH SOME FLURRIES AND/OR LIGHT SNOW SHOWERS. THE PRECIPITATION WILL REMAIN SUFFICIENTLY SPORADIC AND WIDELY SCATTERED TO PRECLUDE A SPECIFIC MENTION IN THE TAFS AT THIS POINT. HOWEVER... IT IS POSSIBLE FUTURE AMENDMENTS MAY BE ABLE TO INCLUDE SOME MVFR VISIBILITIES FOR ACTIVITY IF IT BECOMES MORE CONSISTENT LATER TODAY. CEILINGS COULD BRIEFLY DROP TO AROUND 030 AT TIMES TODAY... PARTICULARLY WITH ANY PCPN... BUT ONCE AGAIN IT IS TOO TOUGH TO TRY AND PIN DOWN WHEN/WHERE THAT MIGHT OCCUR AT THIS POINT. SO... KEPT THINGS VFR WITH RESPECT TO CEILINGS AND DIDN/T INCLUDE ANY SPECIFIC MENTION OF PCPN OR VISIBILITY REDUCTION IN THE TAFS. WITH THINGS CHANGING LITTLE ON THE LARGE SCALE THROUGH THE FORECAST PERIOD... CHOSE NOT TO SCATTER OUT CEILINGS AT ANY TIME... EXCEPT FOR THE TAIL END OF THE KMSP TAF WHICH GOES OUR FURTHER IN TIME AND REACHES A POINT WHEN THERE IS MUCH LESS IN THE WAY OF A CAPPING INVERSION TO TRAP MOISTURE/CLOUDS. KMSP...CONFIDENCE IS RATHER HIGH IN THE OVERALL VFR CONDITIONS... BUT THERE IS SOME UNCERTAINTY WITH RESPECT TO SCATTERED PCPN TODAY. CEILINGS AND VISIBILITIES COULD BRIEFLY DIP INTO MVFR IF ANY OF THAT ACTIVITY MOVES THROUGH THE AREA... SO SOME AMENDMENTS COULD BECOME NECESSARY SHOULD THAT OCCUR. /OUTLOOK FOR KMSP/ THURSDAY AFTERNOON...VFR. NORTHWEST WIND 5 TO 15 KT. THURSDAY NIGHT...VFR. WEST WIND 5 TO 10 KT. FRIDAY...VFR. SOUTHWEST WIND 10 TO 20 KT INCREASING TO 15 TO 25 KT. FRIDAY NIGHT...MVFR CEILINGS POSSIBLE LATE. SOUTHWEST WIND 15 TO 25 KT BECOMING WEST. SATURDAY...MVFR CEILINGS POSSIBLE. NORTHWEST WIND 10 TO 20 KT. SATURDAY NIGHT...VFR. NORTHWEST WIND 5 TO 15 KT BECOMING VARIABLE LESS THAN 10 KT. SUNDAY...VFR. SOUTH WIND 5 TO 15 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ UPDATE... SHORT TERM... LONG TERM...LS AVIATION...
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
638 AM CDT WED OCT 23 2013 .AVIATION... 12Z TAFS FOR KOMA...KOFK...KLNK A QUICK MOVING STORM SYSTEM WILL IMPACT THE TAF SITES THROUGH THE FIRST 12 HOURS OF THE PERIOD. MID LEVEL CLOUDS ARE INCREASING THIS MORNING AHEAD OF THE SYSTEM AND THE DECK WILL CONTINUE TO LOWER TO AROUND FLIGHT LEVEL 4 TO 5 K FT BY MID MORNING. A BAND OF SHOWERS WILL MOVE FROM NORTHWEST TO SOUTHEAST ACROSS THE AREA AND IMPACT KOFK FIRST AND THEN KOMA ENDING BY EARLY THIS AFTERNOON. WE WILL JUST INCLUDE A VC MENTION AT KLNK ATTM. SOUTHWEST AND WEST WINDS THIS MORNING WILL BECOME NORTH THIS AFTERNOON BEHIND THE SYSTEM BUT REMAIN GENERALLY AOB 12 KT. SKIES WILL CLEAR AT ALL 3 SITES AFTER 06Z THU THRU THE END OF THE PERIOD. BOUSTEAD && .PREV DISCUSSION... /ISSUED 245 AM CDT WED OCT 23 2013/ DISCUSSION... SKIES HAD CLEARED ACROSS MUCH OF EASTERN NEBRASKA AND SOUTHWEST IOWA SINCE 05Z BUT ADDITIONAL CLOUDS OVER THE DAKOTAS ARE EXPECTED TO SPREAD INTO THE AREA PRIOR TO SUNRISE. RADAR ALSO PICKING UP SOME LIGHT PRECIP OVER NORTH CENTRAL SOUTH DAKOTA WITH SHORT RANGE MODELS BRINGING THE PRECIP INTO THE AREA DURING THE MORNING. AS THE CLOUD COVER RETURNS TO BLANKET THE AREA THIS MORNING WE SHOULD SEE TEMPERATURES WARM. RAP FORECAST SOUNDINGS SHOW RAIN TO BE PRIMARY PRECIP TYPE...ALTHOUGH A MIX IS POSSIBLE NORTH OF OMAHA IF ACTUAL TIMING IS FASTER THAN EXPECTED. PERIODS OF SHOWERS THEN EXPECTED THROUGH THE DAY OVER EASTERN PARTS OF THE AREA BUT ENDING NORTH TO SOUTH DURING THE AFTERNOON. REMAINDER OF THE SHORT TERM LOOKS DRY BUT COLD FOR TONIGHT WITH A HARD FREEZE LIKELY ACROSS NORTHERN PARTS OF THE AREA. LIGHT WINDS ON THURSDAY WITH HIGH PRESSURE OVER THE AREA EXPECTED TO HOLD TEMPERATURES IN THE 40S BUT WARMER TEMPERATURES RETURN FRIDAY INTO THE WEEKEND. EXTENDED PERIOD EARLY NEXT WEEK STILL PROBLEMATIC AS OPERATIONAL MODELS DIFFER IN HANDLING OF ENERGY COMING INTO THE GREAT BASIN ON MONDAY AND EVOLUTION OF THE SYSTEM AS IT TRACKS EAST TOWARD THE SOUTHERN PLAINS TUESDAY AND WEDNESDAY. HAVE MAINTAINED CURRENT TRENDS IN THE FORECAST BUT HIGHS ON MONDAY UNCERTAIN DUE TO TIMING AND STRENGTH OF THE FRONT BY THE GFS AND ECMWF. FOBERT && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1028 AM EDT WED OCT 23 2013 .SYNOPSIS... A SERIES OF COLD FRONTS WILL PUSH ACROSS THE AREA TODAY THROUGH FRIDAY...BRINGING INCREASINGLY COLD AND DRY CONDITIONS. WELL BELOW NORMAL TEMPERATURES ARE EXPECTED LATE WEEK INTO THE WEEKEND...AND THE FIRST FROST OR FREEZE OF THE SEASON COULD OCCUR FRIDAY NIGHT. SLOW WARMING WILL BEGIN SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM WEDNESDAY...SCT/BKN CLOUD COVER CONTINUES TO COVER MAINLY OUR NC COUNTIES THIS MORNING...WHILE A MAJORITY OF OUR SC COUNTIES HAVE FOR THE MOST PART CLEARED OUT. THOUGH WE WILL SEE PERIODS OF SCT/BKN CLOUDS THROUGHOUT THE DAY...STILL EXPECT TEMPS TO CLIMB INTO THE 70S THIS AFTERNOON...WITH MOST AREAS IN THE LOW TO MID 60S ALREADY THIS MORNING. ONLY MINOR ADJUSTMENTS TO TEMPS...DEW POINTS...AND SKY COVER WERE NEEDED FOR THIS MORNING UPDATE. OTHERWISE GOING FORECAST IS IN GOOD SHAPE. PREVIOUS DISCUSSION FOLLOWS............................................ AS OF 630 AM WEDNESDAY...VARIOUS MODEL TIME HEIGHT SECTIONS FOR VARIOUS LOCATIONS ACROSS THE ILM CWA INDICATE THE DEEPEST MOISTURE HAS BASICALLY MOVED OFF THE ILM CWA COAST...ALONG WITH DRIER AIR ALOFT PROGRESSING ACROSS THE FA. RESIDUAL MOISTURE BELOW 8H ALONG WITH CAA OVERSPREADING THE FA LATER THIS MORNING AND AFTERNOON...COULD RESULT WITH A SCATTERED/BROKEN SC/CU DECK OF CLOUDS AND THUS WILL NOT GO COMPLETELY CLEAR UNTIL TONIGHT. THE RATHER LARGE AMPLITUDE 5H TROF AXIS...INDIGENOUS TO WINTER SEASON...WILL LIE OVERHEAD COME THIS EVENING AND OVERNIGHT...AND THUS WILL NO LONGER BE ABLE TO TAP GULF OF MEXICO MOISTURE AS WELL AS ATLANTIC OCEAN MOISTURE. THERE ARE CLIPPER TYPE VORTICIES...UPPER S/W TROFS...DIVING SE FROM CANADA THAT WILL AID IN KEEPING THIS WELL CARVED AND LARGE AMPLITUDE UPPER TROF IN TACT FOR THE EASTERN ONE THIRD OF THE U.S. DURING THIS TIME PERIOD...AND EXTENDING WELL INTO THE SHORT TERM PERIOD. MOST TO PASS N OF THE FA...HOWEVER 1 LATE TONIGHT INTO THE SHORT TERM PERIOD...WILL HAVE ENOUGH MOISTURE ACCOMPANYING WITH IT...AND COULD RESULT IN A SCT/BKN MID-LEVEL CLOUD DECK BY DAYBREAK THU. CAA WILL CONTINUE TONIGHT WITH THE 0 DEGREE ISOTHERM ALOFT HAVING DROPPED TO THE 800MB LEVEL COME DAYBREAK THU...AND LIKELY TO FURTHER DROP TO THE 850MB LEVEL DURING THE SHORT TERM PERIOD. A DOWNSLOPE TRAJECTORY WITH W-NW FLOW WILL AFFECT THE AREA WITH MAX TEMPS TODAY THAT MAY ACTUALLY BE WARMER ALONG THE IMMEDIATE COAST THEN THEIR INLAND COUNTERPARTS. FOR TODAYS MAX TEMPS...HAVE UTILIZED VARIOUS MODEL MOS GUIDANCE THAT BASICALLY ILLUSTRATE 70-75 INLAND AND MID 70S AT THE COAST. AS FOR TONIGHTS MINS...WILL STAY AT OR SLIGHTLY ABOVE COMPROMISED MODEL MOS GUIDANCE. DO NOT EXPECT A SFC BASED INVERSION AS LOW LEVEL WINDS REMAIN ACTIVE THUS PREVENTING ANY DECOUPLING OR DECENT RADIATIONAL COOLING. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...AS WE APPROACH HALLOWEEN...JACK-O-LANTERNS, GHOSTS, AND WITCHES BEGIN TO CROP UP ACROSS THE AREA...AND IT APPEARS ONE OF THESE WITCHES HAS CAST A SPELL OF WINTER-LIKE WEATHER WHICH WILL IMPACT THE CAROLINAS THROUGH THE SHORT TERM. ABUNDANT SUNSHINE THURSDAY/FRIDAY WILL DO LITTLE TO HELP AFTN TEMP RECOVERY...AND BOTH DAYS WILL BE AROUND 10 DEGREES BELOW CLIMO FOR LATE-OCTOBER. THIS IS DUE TO A COMBINATION OF A LARGE AND STRONG UPPER TROUGH DOMINATING THE EASTERN HALF OF THE COUNTRY...AND A COLD CANADIAN HIGH PRESSURE EXTENDING BENEATH IT. WHILE THURSDAY WILL BE COOL...A SECONDARY AND COLDER SURGE OF AIR /DRY COLD FRONT/ WILL CROSS SOUTH EARLY FRIDAY...MAKING FRIDAY SEVERAL DEGREES COOLER THAN THE ALREADY COOL THURSDAY. IN FACT...LATEST GEFS HAS THE CORE OF THE ABSOLUTE COLDEST 850MB AIR /-3 TO -4 SD`S!/ DRIFTING OVERHEAD FRIDAY...AND FRIDAY NIGHT LOOKS TO BE THE COLDEST NIGHT IN THIS AREA SINCE APRIL 7TH. SO WITH HIGH PRESSURE DOMINATING AND SUNSHINE ABUNDANT...FORECAST BECOMES SOLELY DEPENDENT ON TEMPERATURES. THURSDAY WILL BE COOL...WITH HIGHS RISING INTO THE MID 60S...ABOUT 4-8 DEGREES BELOW NORMAL. EVEN COLDER ON FRIDAY...WHEN HIGHS WILL STRUGGLE TO AROUND 60...AND EXPECT MANY PLACES IN THE NC ZONES WILL STAY IN THE UPPER 50S...AVERAGE HIGHS FOR DECEMBER. LOWS THURSDAY NIGHT WILL DROP TO A DEGREE OR TWO ABOVE 40...BEFORE PLUMMETING FRIDAY NIGHT INTO THE MID...OR EVEN LOW 30S! THIS PROMOTES THE POTENTIAL FOR FROST ACROSS THE AREA FRIDAY NIGHT...AND WITH WINDS AT THE TOP OF THE RESIDUAL LAYER FRIDAY NIGHT ONLY FORECAST TO BE 2-5 KTS...IDEAL RADIATIONAL COOLING MAY ALLOW THE COOLER SPOTS TO DROP TO FREEZING. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...PERIOD STARTS WITH ONE MORE WELL BELOW NORMAL DAY AS 850MB TEMPS AROUND 0C COMBINE WITH CANADIAN HIGH PRESSURE AND 5H TROUGH TO KEEP TEMPS FROM RISING MUCH PAST 60. BEYOND SATURDAY...SURFACE HIGH BEGINS TO MIGRATE TO THE NORTHEAST ALLOWING FOR SLOW WARMING ON RETURN FLOW...AND 1000-500MB THICKNESSES SLOWLY INCREASE DOWNSTREAM OF A 5H LOW DROPPING ACROSS THE MTN WEST. THE CENTER OF THE SURFACE HIGH WILL MOVE INTO NEW ENGLAND...CAUSING DEVELOPING NE FLOW...AND THIS WILL LIMIT SIGNIFICANT WARMING. STILL...TEMPS WILL RECOVER TO SEASONABLE LEVELS BY EARLY NEXT WEEK. NO PRECIP EXPECTED THROUGH THE PERIOD. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...MVFR/IFR CIGS HAVE DEVELOPED THIS MORNING AHEAD OF A COLD FRONT THAT WILL CROSS OUR CWA LATER TODAY. SOME TEMPO IFR CIGS ARE POSSIBLE JUST AFTER 12Z...BUT ANY CIGS BELOW 1KFT ARE EXPECTED TO BE SHORT-LIVED. OTHERWISE EXPECT MVFR TO PREVAIL THIS MORNING... BECOMING VFR BY MIDDAY AS DEEP WESTERLY FLOW BRINGS COOLER AND DRIER AIR INTO THE REGION. FCST SOUNDINGS SHOW RESIDUAL LOW LEVEL MOISTURE SUGGESTIVE OF SCT/BKN CU 5-6KFT THIS AFTN. EXPECT WEST WINDS 10-15 KTS WITH GUSTS OF 20-25 KTS ACROSS THE AREA AFTER 16Z. THESE GUSTS WILL SUBSIDE BY 00Z THURSDAY AS THE WINDS BECOME NORTHWEST AOB 8 KTS OVERNIGHT UNDER CLEAR SKIES. EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH THE EXTENDED PERIOD. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1025 AM WEDNESDAY...NO ADJUSTMENTS WERE NEEDED ATTM. PREVIOUS DISCUSSION FOLLOWS.............AS OF 630 AM WEDNESDAY...SCA IS IN EFFECT FOR ALL COASTAL ZONES MAINLY DUE TO WIND SPEEDS OF 15-25 KT WITH HIER GUSTS. LIMITED FETCH WILL KEEP 6 FOOT OR HIER SEAS RIGHT AT THE CUSP OR BOUNDARY BETWEEN THE COASTAL AND OFFSHORE WATERS...MAINLY OFF CAPE FEAR. THE SFC COLD FRONT HAS PUSHED EAST...OFF THE MAINLAND...ACROSS THE ILM WATERS...AND NOW OFFSHORE. SW-W 10-15 KT WINDS WILL VEER TO W TO WNW 10 TO 20 KT WITH HIER GUSTS THIS MORNING. FOR THIS AFTERNOON AND EVENING...A TIGHTENING SFC PG COMBINED WITH DECENT CAA WILL RESULT WITH WNW-NW INCREASING WINDS TO 15 TO 25 KT WITH SOME HIER GUSTS. LATEST HRRR HIGHLIGHTS THIS SFC WIND FIELD OVERSPREADING THE WATERS INTO TONIGHT. SIGNIFICANT SEAS WILL BUILD TO 3 TO 6 FT...WITH THE 6 FOOTERS PRIMARILY ACROSS THE OUTER WATERS OFF CAPE FEAR. AVERAGE PERIODS WILL RUN 4 TO 5 SECONDS...WITH DOMINATE PERIODS AT 6 TO 7 SECONDS. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...NW WINDS OF 10-15 KTS TO START THURSDAY WILL EASE THROUGH THE DAY AS COOL HIGH PRESSURE BUILDS ACROSS THE WATERS...WEAKENING THE PRESSURE GRADIENT. THE LIGHTER WINDS WILL BE SHORT-LIVED HOWEVER...THANKS TO A DRY COLD FRONT WHICH WILL CROSS THE WATERS EARLY FRIDAY. THIS WILL CAUSE A RENEWED SURGE OF N/NW WINDS ALL OF FRIDAY...INCREASING TO 15-20 KTS THROUGH THE END OF THE PERIOD. THE SEA STATE WILL BE ENTIRELY WIND-WAVE DOMINATED...WITH A 4-5 SEC NORTHERLY WIND CHOP THE MOST SIGNIFICANT WAVE GROUP. WAVE HEIGHTS WILL BE LIMITED THANKS TO THE OFFSHORE WIND COMPONENT...REACHING 1-3 FT THROUGH THE PERIOD. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...HIGH PRESSURE MOVING NEAR THE WATERS THROUGH THE PERIOD WILL KEEP A RELATIVELY WEAK GRADIENT...THUS KEEPING WINDS LIGHT. ALTHOUGH WIND DIRECTION WILL SHIFT FROM NORTH EARLY SATURDAY...BACK TO WEST...AND EVENTUALLY RETURN TO THE NE BY LATE SUNDAY...SPEEDS WILL BE AROUND 10 KTS THROUGH THE EXTENDED. SEAS WILL BE ONLY 1-2 FT THANKS TO THE LIGHT WINDS AND LACK OF ANY SIGNIFICANT SWELL...WITH A VARIABLE WAVE DIRECTION FOLLOWING THE WIND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR AMZ250-252- 254-256. && $$ SYNOPSIS...JDW NEAR TERM...DCH/SGL SHORT TERM...JDW LONG TERM...JDW AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
728 AM EDT WED OCT 23 2013 .SYNOPSIS... A SERIES OF COLD FRONTS WILL PUSH ACROSS THE AREA TODAY THROUGH FRIDAY...BRINGING INCREASINGLY COLD AND DRY CONDITIONS. WELL BELOW NORMAL TEMPERATURES ARE EXPECTED LATE WEEK INTO THE WEEKEND...AND THE FIRST FROST OR FREEZE OF THE SEASON COULD OCCUR FRIDAY NIGHT. SLOW WARMING WILL BEGIN SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM WEDNESDAY...VARIOUS MODEL TIME HEIGHT SECTIONS FOR VARIOUS LOCATIONS ACROSS THE ILM CWA INDICATE THE DEEPEST MOISTURE HAS BASICALLY MOVED OFF THE ILM CWA COAST...ALONG WITH DRIER AIR ALOFT PROGRESSING ACROSS THE FA. RESIDUAL MOISTURE BELOW 8H ALONG WITH CAA OVERSPREADING THE FA LATER THIS MORNING AND AFTERNOON...COULD RESULT WITH A SCATTERED/BROKEN SC/CU DECK OF CLOUDS AND THUS WILL NOT GO COMPLETELY CLEAR UNTIL TONIGHT. THE RATHER LARGE AMPLITUDE 5H TROF AXIS...INDIGENOUS TO WINTER SEASON...WILL LIE OVERHEAD COME THIS EVENING AND OVERNIGHT...AND THUS WILL NO LONGER BE ABLE TO TAP GULF OF MEXICO MOISTURE AS WELL AS ATLANTIC OCEAN MOISTURE. THERE ARE CLIPPER TYPE VORTICIES...UPPER S/W TROFS...DIVING SE FROM CANADA THAT WILL AID IN KEEPING THIS WELL CARVED AND LARGE AMPLITUDE UPPER TROF IN TACT FOR THE EASTERN ONE THIRD OF THE U.S. DURING THIS TIME PERIOD...AND EXTENDING WELL INTO THE SHORT TERM PERIOD. MOST TO PASS N OF THE FA...HOWEVER 1 LATE TONIGHT INTO THE SHORT TERM PERIOD...WILL HAVE ENOUGH MOISTURE ACCOMPANYING WITH IT...AND COULD RESULT IN A SCT/BKN MID-LEVEL CLOUD DECK BY DAYBREAK THU. CAA WILL CONTINUE TONIGHT WITH THE 0 DEGREE ISOTHERM ALOFT HAVING DROPPED TO THE 800MB LEVEL COME DAYBREAK THU...AND LIKELY TO FURTHER DROP TO THE 850MB LEVEL DURING THE SHORT TERM PERIOD. A DOWNSLOPE TRAJECTORY WITH W-NW FLOW WILL AFFECT THE AREA WITH MAX TEMPS TODAY THAT MAY ACTUALLY BE WARMER ALONG THE IMMEDIATE COAST THEN THEIR INLAND COUNTERPARTS. FOR TODAYS MAX TEMPS...HAVE UTILIZED VARIOUS MODEL MOS GUIDANCE THAT BASICALLY ILLUSTRATE 70-75 INLAND AND MID 70S AT THE COAST. AS FOR TONIGHTS MINS...WILL STAY AT OR SLIGHTLY ABOVE COMPROMISED MODEL MOS GUIDANCE. DO NOT EXPECT A SFC BASED INVERSION AS LOW LEVEL WINDS REMAIN ACTIVE THUS PREVENTING ANY DECOUPLING OR DECENT RADIATIONAL COOLING. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...AS WE APPROACH HALLOWEEN...JACK-O-LANTERNS, GHOSTS, AND WITCHES BEGIN TO CROP UP ACROSS THE AREA...AND IT APPEARS ONE OF THESE WITCHES HAS CAST A SPELL OF WINTER-LIKE WEATHER WHICH WILL IMPACT THE CAROLINAS THROUGH THE SHORT TERM. ABUNDANT SUNSHINE THURSDAY/FRIDAY WILL DO LITTLE TO HELP AFTN TEMP RECOVERY...AND BOTH DAYS WILL BE AROUND 10 DEGREES BELOW CLIMO FOR LATE-OCTOBER. THIS IS DUE TO A COMBINATION OF A LARGE AND STRONG UPPER TROUGH DOMINATING THE EASTERN HALF OF THE COUNTRY...AND A COLD CANADIAN HIGH PRESSURE EXTENDING BENEATH IT. WHILE THURSDAY WILL BE COOL...A SECONDARY AND COLDER SURGE OF AIR /DRY COLD FRONT/ WILL CROSS SOUTH EARLY FRIDAY...MAKING FRIDAY SEVERAL DEGREES COOLER THAN THE ALREADY COOL THURSDAY. IN FACT...LATEST GEFS HAS THE CORE OF THE ABSOLUTE COLDEST 850MB AIR /-3 TO -4 SD`S!/ DRIFTING OVERHEAD FRIDAY...AND FRIDAY NIGHT LOOKS TO BE THE COLDEST NIGHT IN THIS AREA SINCE APRIL 7TH. SO WITH HIGH PRESSURE DOMINATING AND SUNSHINE ABUNDANT...FORECAST BECOMES SOLELY DEPENDENT ON TEMPERATURES. THURSDAY WILL BE COOL...WITH HIGHS RISING INTO THE MID 60S...ABOUT 4-8 DEGREES BELOW NORMAL. EVEN COLDER ON FRIDAY...WHEN HIGHS WILL STRUGGLE TO AROUND 60...AND EXPECT MANY PLACES IN THE NC ZONES WILL STAY IN THE UPPER 50S...AVERAGE HIGHS FOR DECEMBER. LOWS THURSDAY NIGHT WILL DROP TO A DEGREE OR TWO ABOVE 40...BEFORE PLUMMETING FRIDAY NIGHT INTO THE MID...OR EVEN LOW 30S! THIS PROMOTES THE POTENTIAL FOR FROST ACROSS THE AREA FRIDAY NIGHT...AND WITH WINDS AT THE TOP OF THE RESIDUAL LAYER FRIDAY NIGHT ONLY FORECAST TO BE 2-5 KTS...IDEAL RADIATIONAL COOLING MAY ALLOW THE COOLER SPOTS TO DROP TO FREEZING. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...PERIOD STARTS WITH ONE MORE WELL BELOW NORMAL DAY AS 850MB TEMPS AROUND 0C COMBINE WITH CANADIAN HIGH PRESSURE AND 5H TROUGH TO KEEP TEMPS FROM RISING MUCH PAST 60. BEYOND SATURDAY...SURFACE HIGH BEGINS TO MIGRATE TO THE NORTHEAST ALLOWING FOR SLOW WARMING ON RETURN FLOW...AND 1000-500MB THICKNESSES SLOWLY INCREASE DOWNSTREAM OF A 5H LOW DROPPING ACROSS THE MTN WEST. THE CENTER OF THE SURFACE HIGH WILL MOVE INTO NEW ENGLAND...CAUSING DEVELOPING NE FLOW...AND THIS WILL LIMIT SIGNIFICANT WARMING. STILL...TEMPS WILL RECOVER TO SEASONABLE LEVELS BY EARLY NEXT WEEK. NO PRECIP EXPECTED THROUGH THE PERIOD. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 12Z...MVFR/IFR CIGS HAVE DEVELOPED THIS MORNING AHEAD OF A COLD FRONT THAT WILL CROSS OUR CWA LATER TODAY. SOME TEMPO IFR CIGS ARE POSSIBLE JUST AFTER 12Z...BUT ANY CIGS BELOW 1KFT ARE EXPECTED TO BE SHORT-LIVED. OTHERWISE EXPECT MVFR TO PREVAIL THIS MORNING... BECOMING VFR BY MIDDAY AS DEEP WESTERLY FLOW BRINGS COOLER AND DRIER AIR INTO THE REGION. FCST SOUNDINGS SHOW RESIDUAL LOW LEVEL MOISTURE SUGGESTIVE OF SCT/BKN CU 5-6KFT THIS AFTN. EXPECT WEST WINDS 10-15 KTS WITH GUSTS OF 20-25 KTS ACROSS THE AREA AFTER 16Z. THESE GUSTS WILL SUBSIDE BY 00Z THURSDAY AS THE WINDS BECOME NORTHWEST AOB 8 KTS OVERNIGHT UNDER CLEAR SKIES. EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH THE EXTENDED PERIOD. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM WEDNESDAY...SCA IS IN EFFECT FOR ALL COASTAL ZONES MAINLY DUE TO WIND SPEEDS OF 15-25 KT WITH HIER GUSTS. LIMITED FETCH WILL KEEP 6 FOOT OR HIER SEAS RIGHT AT THE CUSP OR BOUNDARY BETWEEN THE COASTAL AND OFFSHORE WATERS...MAINLY OFF CAPE FEAR. THE SFC COLD FRONT HAS PUSHED EAST...OFF THE MAINLAND...ACROSS THE ILM WATERS...AND NOW OFFSHORE. SW-W 10-15 KT WINDS WILL VEER TO W TO WNW 10 TO 20 KT WITH HIER GUSTS THIS MORNING. FOR THIS AFTERNOON AND EVENING...A TIGHTENING SFC PG COMBINED WITH DECENT CAA WILL RESULT WITH WNW-NW INCREASING WINDS TO 15 TO 25 KT WITH SOME HIER GUSTS. LATEST HRRR HIGHLIGHTS THIS SFC WIND FIELD OVERSPREADING THE WATERS INTO TONIGHT. SIGNIFICANT SEAS WILL BUILD TO 3 TO 6 FT...WITH THE 6 FOOTERS PRIMARILY ACROSS THE OUTER WATERS OFF CAPE FEAR. AVERAGE PERIODS WILL RUN 4 TO 5 SECONDS...WITH DOMINATE PERIODS AT 6 TO 7 SECONDS. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...NW WINDS OF 10-15 KTS TO START THURSDAY WILL EASE THROUGH THE DAY AS COOL HIGH PRESSURE BUILDS ACROSS THE WATERS...WEAKENING THE PRESSURE GRADIENT. THE LIGHTER WINDS WILL BE SHORT-LIVED HOWEVER...THANKS TO A DRY COLD FRONT WHICH WILL CROSS THE WATERS EARLY FRIDAY. THIS WILL CAUSE A RENEWED SURGE OF N/NW WINDS ALL OF FRIDAY...INCREASING TO 15-20 KTS THROUGH THE END OF THE PERIOD. THE SEA STATE WILL BE ENTIRELY WIND-WAVE DOMINATED...WITH A 4-5 SEC NORTHERLY WIND CHOP THE MOST SIGNIFICANT WAVE GROUP. WAVE HEIGHTS WILL BE LIMITED THANKS TO THE OFFSHORE WIND COMPONENT...REACHING 1-3 FT THROUGH THE PERIOD. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...HIGH PRESSURE MOVING NEAR THE WATERS THROUGH THE PERIOD WILL KEEP A RELATIVELY WEAK GRADIENT...THUS KEEPING WINDS LIGHT. ALTHOUGH WIND DIRECTION WILL SHIFT FROM NORTH EARLY SATURDAY...BACK TO WEST...AND EVENTUALLY RETURN TO THE NE BY LATE SUNDAY...SPEEDS WILL BE AROUND 10 KTS THROUGH THE EXTENDED. SEAS WILL BE ONLY 1-2 FT THANKS TO THE LIGHT WINDS AND LACK OF ANY SIGNIFICANT SWELL...WITH A VARIABLE WAVE DIRECTION FOLLOWING THE WIND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR AMZ250-252- 254-256. && $$ SYNOPSIS...JDW NEAR TERM...DCH SHORT TERM...JDW LONG TERM...JDW AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
645 AM EDT WED OCT 23 2013 .SYNOPSIS... A SERIES OF COLD FRONTS WILL PUSH ACROSS THE AREA TODAY THROUGH FRIDAY...BRINGING INCREASINGLY COLD AND DRY CONDITIONS. WELL BELOW NORMAL TEMPERATURES ARE EXPECTED LATE WEEK INTO THE WEEKEND...AND THE FIRST FROST OR FREEZE OF THE SEASON COULD OCCUR FRIDAY NIGHT. SLOW WARMING WILL BEGIN SUNDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM WEDNESDAY...VARIOUS MODEL TIME HEIGHT SECTIONS FOR VARIOUS LOCATIONS ACROSS THE ILM CWA INDICATE THE DEEPEST MOISTURE HAS BASICALLY MOVED OFF THE ILM CWA COAST...ALONG WITH DRIER AIR ALOFT PROGRESSING ACROSS THE FA. RESIDUAL MOISTURE BELOW 8H ALONG WITH CAA OVERSPREADING THE FA LATER THIS MORNING AND AFTERNOON...COULD RESULT WITH A SCATTERED/BROKEN SC/CU DECK OF CLOUDS AND THUS WILL NOT GO COMPLETELY CLEAR UNTIL TONIGHT. THE RATHER LARGE AMPLITUDE 5H TROF AXIS...INDIGENOUS TO WINTER SEASON...WILL LIE OVERHEAD COME THIS EVENING AND OVERNIGHT...AND THUS WILL NO LONGER BE ABLE TO TAP GULF OF MEXICO MOISTURE AS WELL AS ATLANTIC OCEAN MOISTURE. THERE ARE CLIPPER TYPE VORTICIES...UPPER S/W TROFS...DIVING SE FROM CANADA THAT WILL AID IN KEEPING THIS WELL CARVED AND LARGE AMPLITUDE UPPER TROF IN TACT FOR THE EASTERN ONE THIRD OF THE U.S. DURING THIS TIME PERIOD...AND EXTENDING WELL INTO THE SHORT TERM PERIOD. MOST TO PASS N OF THE FA...HOWEVER 1 LATE TONIGHT INTO THE SHORT TERM PERIOD...WILL HAVE ENOUGH MOISTURE ACCOMPANYING WITH IT...AND COULD RESULT IN A SCT/BKN MID-LEVEL CLOUD DECK BY DAYBREAK THU. CAA WILL CONTINUE TONIGHT WITH THE 0 DEGREE ISOTHERM ALOFT HAVING DROPPED TO THE 800MB LEVEL COME DAYBREAK THU...AND LIKELY TO FURTHER DROP TO THE 850MB LEVEL DURING THE SHORT TERM PERIOD. A DOWNSLOPE TRAJECTORY WITH W-NW FLOW WILL AFFECT THE AREA WITH MAX TEMPS TODAY THAT MAY ACTUALLY BE WARMER ALONG THE IMMEDIATE COAST THEN THEIR INLAND COUNTERPARTS. FOR TODAYS MAX TEMPS...HAVE UTILIZED VARIOUS MODEL MOS GUIDANCE THAT BASICALLY ILLUSTRATE 70-75 INLAND AND MID 70S AT THE COAST. AS FOR TONIGHTS MINS...WILL STAY AT OR SLIGHTLY ABOVE COMPROMISED MODEL MOS GUIDANCE. DO NOT EXPECT A SFC BASED INVERSION AS LOW LEVEL WINDS REMAIN ACTIVE THUS PREVENTING ANY DECOUPLING OR DECENT RADIATIONAL COOLING. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...AS WE APPROACH HALLOWEEN...JACK-O-LANTERNS, GHOSTS, AND WITCHES BEGIN TO CROP UP ACROSS THE AREA...AND IT APPEARS ONE OF THESE WITCHES HAS CAST A SPELL OF WINTER-LIKE WEATHER WHICH WILL IMPACT THE CAROLINAS THROUGH THE SHORT TERM. ABUNDANT SUNSHINE THURSDAY/FRIDAY WILL DO LITTLE TO HELP AFTN TEMP RECOVERY...AND BOTH DAYS WILL BE AROUND 10 DEGREES BELOW CLIMO FOR LATE-OCTOBER. THIS IS DUE TO A COMBINATION OF A LARGE AND STRONG UPPER TROUGH DOMINATING THE EASTERN HALF OF THE COUNTRY...AND A COLD CANADIAN HIGH PRESSURE EXTENDING BENEATH IT. WHILE THURSDAY WILL BE COOL...A SECONDARY AND COLDER SURGE OF AIR /DRY COLD FRONT/ WILL CROSS SOUTH EARLY FRIDAY...MAKING FRIDAY SEVERAL DEGREES COOLER THAN THE ALREADY COOL THURSDAY. IN FACT...LATEST GEFS HAS THE CORE OF THE ABSOLUTE COLDEST 850MB AIR /-3 TO -4 SD`S!/ DRIFTING OVERHEAD FRIDAY...AND FRIDAY NIGHT LOOKS TO BE THE COLDEST NIGHT IN THIS AREA SINCE APRIL 7TH. SO WITH HIGH PRESSURE DOMINATING AND SUNSHINE ABUNDANT...FORECAST BECOMES SOLELY DEPENDENT ON TEMPERATURES. THURSDAY WILL BE COOL...WITH HIGHS RISING INTO THE MID 60S...ABOUT 4-8 DEGREES BELOW NORMAL. EVEN COLDER ON FRIDAY...WHEN HIGHS WILL STRUGGLE TO AROUND 60...AND EXPECT MANY PLACES IN THE NC ZONES WILL STAY IN THE UPPER 50S...AVERAGE HIGHS FOR DECEMBER. LOWS THURSDAY NIGHT WILL DROP TO A DEGREE OR TWO ABOVE 40...BEFORE PLUMMETING FRIDAY NIGHT INTO THE MID...OR EVEN LOW 30S! THIS PROMOTES THE POTENTIAL FOR FROST ACROSS THE AREA FRIDAY NIGHT...AND WITH WINDS AT THE TOP OF THE RESIDUAL LAYER FRIDAY NIGHT ONLY FORECAST TO BE 2-5 KTS...IDEAL RADIATIONAL COOLING MAY ALLOW THE COOLER SPOTS TO DROP TO FREEZING. && .LONG TERM /SATURDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY...PERIOD STARTS WITH ONE MORE WELL BELOW NORMAL DAY AS 850MB TEMPS AROUND 0C COMBINE WITH CANADIAN HIGH PRESSURE AND 5H TROUGH TO KEEP TEMPS FROM RISING MUCH PAST 60. BEYOND SATURDAY...SURFACE HIGH BEGINS TO MIGRATE TO THE NORTHEAST ALLOWING FOR SLOW WARMING ON RETURN FLOW...AND 1000-500MB THICKNESSES SLOWLY INCREASE DOWNSTREAM OF A 5H LOW DROPPING ACROSS THE MTN WEST. THE CENTER OF THE SURFACE HIGH WILL MOVE INTO NEW ENGLAND...CAUSING DEVELOPING NE FLOW...AND THIS WILL LIMIT SIGNIFICANT WARMING. STILL...TEMPS WILL RECOVER TO SEASONABLE LEVELS BY EARLY NEXT WEEK. NO PRECIP EXPECTED THROUGH THE PERIOD. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...MVFR CONDITIONS WILL RULE THE PRE-DAWN WED HOURS DUE TO REDUCED VSBY FROM -SHRA AND CLOUD DECKS BELOW 3K FT. IFR CONDITIONS REMAIN POSSIBLE AFTER THE PCPN CEASES...WITH 2SM VSBY FROM FOG AND/OR A BRIEF LOW CLOUD DECK BETWEEN 1K AND 2K FEET. COLD FRONTAL PASSAGE WILL OCCUR FROM WEST TO EAST EARLY THIS AM. BY DAYBREAK WED...THE COLD FRONT SHOULD BE OFF THE CAROLINA COASTS...AS ILLUSTRATING BY VARIOUS MODELS SFC STREAMLINE FCSTS. VARIOUS MODEL TIME HEIGHT SECTIONS ILLUSTRATE THE DRIER AIR THROUGHOUT THE ATM COLUMN WILL OVERSPREAD THE FA LATER THIS MORNING...AND ESPECIALLY THIS AFTN AND EVENING. THE DOWNSLOPE TRAJECTORY IN THE WIND FIELDS BOTH SFC AND ALOFT...WILL ALSO PROVIDE A SCOURING OF ANY RESIDUAL MOISTURE. WINDS WILL ALSO BECOME QUITE ACTIVE SFC-ALOFT. THE CAA COMBINING WITH A TIGHTENED SFC PG...WILL RESULT WITH W TO NW WINDS AT 15 TO 25 KT. THE WIND INSTRUMENTATION AT THE CRE TERMINAL IS SOMEWHAT PROTECTED DURING W TO NW WIND EVENTS...AND AS A RESULT WILL CHOP OFF 5+ KT OFF CRE TAF DURING TODAY. EXTENDED OUTLOOK...EXPECT VFR THROUGH THE EXTENDED. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 630 AM WEDNESDAY...SCA IS IN EFFECT FOR ALL COASTAL ZONES MAINLY DUE TO WIND SPEEDS OF 15-25 KT WITH HIER GUSTS. LIMITED FETCH WILL KEEP 6 FOOT OR HIER SEAS RIGHT AT THE CUSP OR BOUNDARY BETWEEN THE COASTAL AND OFFSHORE WATERS...MAINLY OFF CAPE FEAR. THE SFC COLD FRONT HAS PUSHED EAST...OFF THE MAINLAND...ACROSS THE ILM WATERS...AND NOW OFFSHORE. SW-W 10-15 KT WINDS WILL VEER TO W TO WNW 10 TO 20 KT WITH HIER GUSTS THIS MORNING. FOR THIS AFTERNOON AND EVENING...A TIGHTENING SFC PG COMBINED WITH DECENT CAA WILL RESULT WITH WNW-NW INCREASING WINDS TO 15 TO 25 KT WITH SOME HIER GUSTS. LATEST HRRR HIGHLIGHTS THIS SFC WIND FIELD OVERSPREADING THE WATERS INTO TONIGHT. SIGNIFICANT SEAS WILL BUILD TO 3 TO 6 FT...WITH THE 6 FOOTERS PRIMARILY ACROSS THE OUTER WATERS OFF CAPE FEAR. AVERAGE PERIODS WILL RUN 4 TO 5 SECONDS...WITH DOMINATE PERIODS AT 6 TO 7 SECONDS. SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... AS OF 300 AM WEDNESDAY...NW WINDS OF 10-15 KTS TO START THURSDAY WILL EASE THROUGH THE DAY AS COOL HIGH PRESSURE BUILDS ACROSS THE WATERS...WEAKENING THE PRESSURE GRADIENT. THE LIGHTER WINDS WILL BE SHORT-LIVED HOWEVER...THANKS TO A DRY COLD FRONT WHICH WILL CROSS THE WATERS EARLY FRIDAY. THIS WILL CAUSE A RENEWED SURGE OF N/NW WINDS ALL OF FRIDAY...INCREASING TO 15-20 KTS THROUGH THE END OF THE PERIOD. THE SEA STATE WILL BE ENTIRELY WIND-WAVE DOMINATED...WITH A 4-5 SEC NORTHERLY WIND CHOP THE MOST SIGNIFICANT WAVE GROUP. WAVE HEIGHTS WILL BE LIMITED THANKS TO THE OFFSHORE WIND COMPONENT...REACHING 1-3 FT THROUGH THE PERIOD. LONG TERM /SATURDAY THROUGH SUNDAY/... AS OF 300 AM WEDNESDAY...HIGH PRESSURE MOVING NEAR THE WATERS THROUGH THE PERIOD WILL KEEP A RELATIVELY WEAK GRADIENT...THUS KEEPING WINDS LIGHT. ALTHOUGH WIND DIRECTION WILL SHIFT FROM NORTH EARLY SATURDAY...BACK TO WEST...AND EVENTUALLY RETURN TO THE NE BY LATE SUNDAY...SPEEDS WILL BE AROUND 10 KTS THROUGH THE EXTENDED. SEAS WILL BE ONLY 1-2 FT THANKS TO THE LIGHT WINDS AND LACK OF ANY SIGNIFICANT SWELL...WITH A VARIABLE WAVE DIRECTION FOLLOWING THE WIND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR AMZ250-252- 254-256. && $$ SYNOPSIS...JDW NEAR TERM...DCH SHORT TERM...JDW LONG TERM...JDW AVIATION...DCH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1018 AM EDT WED OCT 23 2013 .SYNOPSIS... A WEAK ALBERTA CLIPPER STORM SYSTEM WILL MOVE EAST ACROSS THE REGION TODAY. A COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA BY THURSDAY MORNING AND BECOME NEARLY STATIONARY OVER THE LOCAL AREA. HIGH PRESSURE WILL MOVE EAST INTO THE OHIO AND TENNESSEE VALLEYS AT THE SAME TIME. THE HIGH WILL EVENTUALLY DISSIPATE BY THURSDAY NIGHT AS ANOTHER HIGH BUILDS SOUTHEAST INTO THE OHIO VALLEY BY FRIDAY MORNING. YET ANOTHER COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA ON FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... RADAR SHOWS BAND OF PRECIPITATION STRETCHING FROM LORAIN COUNTY OHIO INTO PENNSYLVANIA. EXPECT THIS BAND TO DRIFT SOUTH OVER THE NEXT COUPLE OF HOURS AND LESSEN IN INTENSITY AS IT DRIFTS. PRECIPITATION WILL GENERALLY REMAIN AS RAIN. HIGHER ELEVATION LOCATIONS...ESPECIALLY THOSE AWAY FROM THE LAKE ERIE SHORE....COULD SEE A TRACE OF SNOW OR MIXED PRECIPITATION OVER THE NEXT COUPLE OF HOURS. HOWEVER...THE PRECIPITATION WILL CHANGE BACK TO RAIN AS TEMPERATURES INCREASE. AS FOR CHANGES TO THE GRIDS...I HAVE INCREASED THE POPS AND CLOUDS WEST AND SOUTH OF CLEVELAND TO ACCOUNT FOR CURRENT TRENDS. PREVIOUS DISCUSSION...A WEAK TROUGH REMAINS PERSISTENT FROM SOUTHWEST TO NORTHEAST OVER THE LAKE RESULTING IN A BAND OF SHOWERS THAT CONTINUES TO DEVELOP ALONG THE LAKE SHORE OF NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA. THIS AREA OF PRECIPITATION IS THE RESULT OF CONSIDERABLE CONVERGENCE ALONG THE SHORE LINE. TEMPERATURES CONTINUE TO HOVER IN THE UPPER 30S TO NEAR 40 DEGREES NEAR THE LAKE AND IN THE MIDDLE 30S ELSEWHERE. SO FAR...NO REPORTS OF SNOW IN THE FORECAST AREA AT THIS TIME. SOME LIGHT SNOW WAS REPORTED AT MARION EARLIER THIS MORNING. OVERALL TREND SHOULD CONTINUE THROUGH THE DAY AS THE CLIPPER LOW PRESSURE SYSTEM SLIDES GRADUALLY EAST ACROSS OHIO INTO PENNSYLVANIA. BULK OF PRECIPITATION STILL REMAINING SOUTH OF THE AREA WHERE THE BEST DYNAMICS IS LOCATED. TEMPERATURES SHOULD REBOUND VERY SLOWLY INTO THE MIDDLE AND UPPER 40S. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ANOTHER SHOT OF COLDER AIR WILL ARRIVE TOWARD MORNING AND I ANTICIPATE WITH 1000 TO 500 MB THICKNESS VALUES DIPPING TO AROUND 525 OR SO OVERNIGHT...WE WILL LIKELY SEE ENOUGH COLD AIR TO SUPPORT THE FINAL KILLING FREEZE OF THE SEASON FOR ALL AREAS EXCEPT EXTREME NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA. WILL GO AHEAD AND ISSUE A FREEZE WATCH FOR TONIGHT. LAKE EFFECT PRECIPITATION AND CLOUDS ALONG WITH WARM INFLUENCE OF THE LAKE SHOULD KEEP TEMPERATURES FROM DIPPING TOO FAR BELOW 33 DEGREES AND WILL HOLD OFF ON A WATCH IN THAT AREA. TEMPERATURES SHOULD WARM UP TO SIMILAR TO WHAT WE WILL SEE TODAY FOR HIGHS ON THURSDAY IN THE MIDDLE 40S. I AM WORRIED THIS MAY BE A BIT TOO WARM DUE TO THE COLD AIR ADVECTION BEHIND THE FRONT EXPECTED. A SHOT OF POSITIVE VORTICITY ADVECTION AND ASSOCIATED MOISTURE WILL ROTATE DOWN ACROSS THE EASTERN HALF OF THE FORECAST AREA ON THURSDAY AND CONVERGENCE COULD POSSIBLY DEVELOP ALONG THE NORTHEAST LAKE SHORE TO PRODUCE A MIX OF SNOW AND RAIN IN THE LAKE EFFECT AREAS. THE REST OF THE FORECAST AREA MAY SEE SOME SPRINKLES BUT WILL LEAVE IT DRY FOR NOW AS MOISTURE IN THIS AREA HOLDS OFF UNTIL EVENING. THURSDAY NIGHT INTO FRIDAY WILL STILL SEE THE EFFECTS OF THE UPPER LEVEL VORTICITY MAXIMUM OVER THE EASTERN HALF OF THE FORECAST AREA. REST OF THE AREA SHOULD REMAIN DRY AT THIS TIME. TEMPERATURE PROFILES SUPPORT A MIX OF RAIN AND SNOW IN THE NORTHEAST THURSDAY NIGHT AND MAINLY RAIN FRIDAY AFTERNOON. THE PRECIPITATION WILL BEGIN TO RETREAT FRIDAY NIGHT FOR A BRIEF PERIOD AS HIGH PRESSURE BRINGS A BRIEF PERIOD OF FAIR WEATHER TO THE FORECAST AREA FRIDAY NIGHT. BUT COLD FRONT WILL SWEEP THROUGH SATURDAY WITH ITS ASSOCIATED MOISTURE AND BRINGS WITH IT A CHANCE FOR MORE SHOWERS. COLD AIR ADVECTION IS NOT EXPECTED TO BE REAL STRONG SO OVERNIGHT LOWS AND DAY TIME HIGHS HOLDING STEADY. && .LONG TERM /SUNDAY THROUGH TUESDAY/... PREVIOUS FORECAST HAD A GOOD HANDLE ON THE BIG PICTURES SO HAVE ONLY MADE MINOR ADJUSTMENTS. HIGH PRESSURE WILL BEGIN TO BUILD OVER THE LOCAL AREA ON SUNDAY WITH JUST A FEW LINGERING SHOWERS POSSIBLE TO THE EAST OF KCLE. WESTERN AREAS SHOULD BE DRY WITH SOME SUNSHINE LIKELY. MONDAY WILL ALSO BE DRY WITH LOT`S OF SUNSHINE AND HIGHS FINALLY RETURNING TO NEAR NORMAL. A STRONG SYSTEM WILL IMPACT THE REGION AT THE END OF THE PERIOD. SHOWERS WILL ARRIVE IN THE WEST LATE MONDAY NIGHT AND SHOULD SPREAD ACROSS THE REMAINDER OF THE AREA ON TUESDAY. SUSPECT THAT WE WILL EVENTUALLY NEED HIGH POPS FOR TUESDAY AND HAVE TRENDED CHANCES UP A LITTLE THIS MORNING. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... A BAND OF SHOWERS HAS BEGUN TO SAG SOUTH OFF OF LAKE ERIE. THIS BAND WILL AFFECT KCLE WITHIN THE HOUR AND AT KYNG IN AN HOUR OR TWO. MOST LOCATIONS REMAIN VFR BUT PERIODS OF MVFR CIGS AND VSBYS WITH THE HEAVIER RAINS. SOME IFR CIGS ARE ALSO BEING REPORTED AT THE SOUTHERN END OF THE AREA. LATEST HRRR MODELS SHOWS SHOWERS ALONG AND EAST OF THE I-71 CORRIDOR. MOST OF THIS ACTIVITY SHOULD BE GONE BY 18Z. SOME SHOWERS WILL LIKELY DEVELOP AND MOVE OFF OF LAKE ERIE LATER THIS AFTERNOON. DRIER AIR SHOULD BEGIN TO WIN OUT TONIGHT AND EXPECT MAINLY VFR CONDITIONS BY 00Z. WESTERLY FLOW WILL BECOME NW TONIGHT AND INCREASE SOME. GUSTS TO 20 KNOTS ARE POSSIBLE THIS AFTERNOON. OUTLOOK...NON-VFR POSSIBLE THROUGH FRIDAY IN RAIN AND SNOW SHOWERS. && .MARINE... WEST TO NORTHWEST FLOW IS EXPECTED ON THE LAKE TODAY WITH SPEEDS INCREASING AFTER DAYBREAK. NORTHWEST FLOW WILL CONTINUE THROUGH FRIDAY AS HIGH PRESSURE PASSES TO THE SOUTH. HAVE EXTENDED THE SMALL CRAFT THROUGH THURSDAY NIGHT AND EXPECT THAT IT WILL EVENTUALLY BE NEEDED FRIDAY AS WELL. SW FLOW WILL FINALLY RETURN TO THE LAKE ON SATURDAY BUT YET ANOTHER COLD FRONT WILL ARRIVE LATE IN THE DAY. THIS WILL CAUSE THE FLOW TO RETURN TO THE NORTHWEST. MORE HEADLINES WILL LIKELY BE NEEDED AS THIS OCCURS. ANOTHER RIDGE WILL MOVE ACROSS THE LAKE ON SUNDAY ENDING THE THREAT FOR PRECIP AND CAUSING THE FLOW TO RETURN TO THE SW BY THE END OF THE PERIOD. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR OHZ003-006>010-017>023-027>033-036>038-047. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR LEZ145>149. SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LEZ142>144. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY/SCHEPEL SHORT TERM...LOMBARDY LONG TERM...KUBINA AVIATION...KUBINA MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
742 AM EDT WED OCT 23 2013 .SYNOPSIS... A WEAK ALBERTA CLIPPER STORM SYSTEM WILL MOVE EAST ACROSS THE REGION TODAY. A COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA BY THURSDAY MORNING AND BECOME NEARLY STATIONARY OVER THE LOCAL AREA. HIGH PRESSURE WILL MOVE EAST INTO THE OHIO AND TENNESSEE VALLEYS AT THE SAME TIME. THE HIGH WILL EVENTUALLY DISSIPATE BY THURSDAY NIGHT AS ANOTHER HIGH BUILDS SOUTHEAST INTO THE OHIO VALLEY BY FRIDAY MORNING. YET ANOTHER COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA ON FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A WEAK TROUGH REMAINS PERSISTENT FROM SOUTHWEST TO NORTHEAST OVER THE LAKE RESULTING IN A BAND OF SHOWERS THAT CONTINUES TO DEVELOP ALONG THE LAKE SHORE OF NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA. THIS AREA OF PRECIPITATION IS THE RESULT OF CONSIDERABLE CONVERGENCE ALONG THE SHORE LINE. TEMPERATURES CONTINUE TO HOVER IN THE UPPER 30S TO NEAR 40 DEGREES NEAR THE LAKE AND IN THE MIDDLE 30S ELSEWHERE. SO FAR...NO REPORTS OF SNOW IN THE FORECAST AREA AT THIS TIME. SOME LIGHT SNOW WAS REPORTED AT MARION EARLIER THIS MORNING. OVERALL TREND SHOULD CONTINUE THROUGH THE DAY AS THE CLIPPER LOW PRESSURE SYSTEM SLIDES GRADUALLY EAST ACROSS OHIO INTO PENNSYLVANIA. BULK OF PRECIPITATION STILL REMAINING SOUTH OF THE AREA WHERE THE BEST DYNAMICS IS LOCATED. TEMPERATURES SHOULD REBOUND VERY SLOWLY INTO THE MIDDLE AND UPPER 40S. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ANOTHER SHOT OF COLDER AIR WILL ARRIVE TOWARD MORNING AND I ANTICIPATE WITH 1000 TO 500 MB THICKNESS VALUES DIPPING TO AROUND 525 OR SO OVERNIGHT...WE WILL LIKELY SEE ENOUGH COLD AIR TO SUPPORT THE FINAL KILLING FREEZE OF THE SEASON FOR ALL AREAS EXCEPT EXTREME NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA. WILL GO AHEAD AND ISSUE A FREEZE WATCH FOR TONIGHT. LAKE EFFECT PRECIPITATION AND CLOUDS ALONG WITH WARM INFLUENCE OF THE LAKE SHOULD KEEP TEMPERATURES FROM DIPPING TOO FAR BELOW 33 DEGREES AND WILL HOLD OFF ON A WATCH IN THAT AREA. TEMPERATURES SHOULD WARM UP TO SIMILAR TO WHAT WE WILL SEE TODAY FOR HIGHS ON THURSDAY IN THE MIDDLE 40S. I AM WORRIED THIS MAY BE A BIT TOO WARM DUE TO THE COLD AIR ADVECTION BEHIND THE FRONT EXPECTED. A SHOT OF POSITIVE VORTICITY ADVECTION AND ASSOCIATED MOISTURE WILL ROTATE DOWN ACROSS THE EASTERN HALF OF THE FORECAST AREA ON THURSDAY AND CONVERGENCE COULD POSSIBLY DEVELOP ALONG THE NORTHEAST LAKE SHORE TO PRODUCE A MIX OF SNOW AND RAIN IN THE LAKE EFFECT AREAS. THE REST OF THE FORECAST AREA MAY SEE SOME SPRINKLES BUT WILL LEAVE IT DRY FOR NOW AS MOISTURE IN THIS AREA HOLDS OFF UNTIL EVENING. THURSDAY NIGHT INTO FRIDAY WILL STILL SEE THE EFFECTS OF THE UPPER LEVEL VORTICITY MAXIMUM OVER THE EASTERN HALF OF THE FORECAST AREA. REST OF THE AREA SHOULD REMAIN DRY AT THIS TIME. TEMPERATURE PROFILES SUPPORT A MIX OF RAIN AND SNOW IN THE NORTHEAST THURSDAY NIGHT AND MAINLY RAIN FRIDAY AFTERNOON. THE PRECIPITATION WILL BEGIN TO RETREAT FRIDAY NIGHT FOR A BRIEF PERIOD AS HIGH PRESSURE BRINGS A BRIEF PERIOD OF FAIR WEATHER TO THE FORECAST AREA FRIDAY NIGHT. BUT COLD FRONT WILL SWEEP THROUGH SATURDAY WITH ITS ASSOCIATED MOISTURE AND BRINGS WITH IT A CHANCE FOR MORE SHOWERS. COLD AIR ADVECTION IS NOT EXPECTED TO BE REAL STRONG SO OVERNIGHT LOWS AND DAY TIME HIGHS HOLDING STEADY. && .LONG TERM /SUNDAY THROUGH TUESDAY/... PREVIOUS FORECAST HAD A GOOD HANDLE ON THE BIG PICTURES SO HAVE ONLY MADE MINOR ADJUSTMENTS. HIGH PRESSURE WILL BEGIN TO BUILD OVER THE LOCAL AREA ON SUNDAY WITH JUST A FEW LINGERING SHOWERS POSSIBLE TO THE EAST OF KCLE. WESTERN AREAS SHOULD BE DRY WITH SOME SUNSHINE LIKELY. MONDAY WILL ALSO BE DRY WITH LOT`S OF SUNSHINE AND HIGHS FINALLY RETURNING TO NEAR NORMAL. A STRONG SYSTEM WILL IMPACT THE REGION AT THE END OF THE PERIOD. SHOWERS WILL ARRIVE IN THE WEST LATE MONDAY NIGHT AND SHOULD SPREAD ACROSS THE REMAINDER OF THE AREA ON TUESDAY. SUSPECT THAT WE WILL EVENTUALLY NEED HIGH POPS FOR TUESDAY AND HAVE TRENDED CHANCES UP A LITTLE THIS MORNING. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... A BAND OF SHOWERS HAS BEGUN TO SAG SOUTH OFF OF LAKE ERIE. THIS BAND WILL AFFECT KCLE WITHIN THE HOUR AND AT KYNG IN AN HOUR OR TWO. MOST LOCATIONS REMAIN VFR BUT PERIODS OF MVFR CIGS AND VSBYS WITH THE HEAVIER RAINS. SOME IFR CIGS ARE ALSO BEING REPORTED AT THE SOUTHERN END OF THE AREA. LATEST HRRR MODELS SHOWS SHOWERS ALONG AND EAST OF THE I-71 CORRIDOR. MOST OF THIS ACTIVITY SHOULD BE GONE BY 18Z. SOME SHOWERS WILL LIKELY DEVELOP AND MOVE OFF OF LAKE ERIE LATER THIS AFTERNOON. DRIER AIR SHOULD BEGIN TO WIN OUT TONIGHT AND EXPECT MAINLY VFR CONDITIONS BY 00Z. WESTERLY FLOW WILL BECOME NW TONIGHT AND INCREASE SOME. GUSTS TO 20 KNOTS ARE POSSIBLE THIS AFTERNOON. OUTLOOK...NON-VFR POSSIBLE THROUGH FRIDAY IN RAIN AND SNOW SHOWERS. && .MARINE... WEST TO NORTHWEST FLOW IS EXPECTED ON THE LAKE TODAY WITH SPEEDS INCREASING AFTER DAYBREAK. NORTHWEST FLOW WILL CONTINUE THROUGH FRIDAY AS HIGH PRESSURE PASSES TO THE SOUTH. HAVE EXTENDED THE SMALL CRAFT THROUGH THURSDAY NIGHT AND EXPECT THAT IT WILL EVENTUALLY BE NEEDED FRIDAY AS WELL. SW FLOW WILL FINALLY RETURN TO THE LAKE ON SATURDAY BUT YET ANOTHER COLD FRONT WILL ARRIVE LATE IN THE DAY. THIS WILL CAUSE THE FLOW TO RETURN TO THE NORTHWEST. MORE HEADLINES WILL LIKELY BE NEEDED AS THIS OCCURS. ANOTHER RIDGE WILL MOVE ACROSS THE LAKE ON SUNDAY ENDING THE THREAT FOR PRECIP AND CAUSING THE FLOW TO RETURN TO THE SW BY THE END OF THE PERIOD. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR OHZ003-006>010-017>023-027>033-036>038-047. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR LEZ145>149. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY SHORT TERM...LOMBARDY LONG TERM...KUBINA AVIATION...KUBINA MARINE...KUBINA
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
609 AM CDT WED OCT 23 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 316 AM CDT WED OCT 23 2013 AT 3 AM...SCATTERED SNOW SHOWERS WERE FOUND FROM MORA MINNESOTA /KJMR/ SOUTH TO DECORAH IOWA. THESE SHOWERS WERE DEVELOPING IN RESPONSE TO A 700 MB TROUGH ACROSS CENTRAL WISCONSIN AND CENTRAL MINNESOTA AND 925 TO 700 MB LAPSE RATES RUNNING NEAR 7 C/KM. THE 23.00Z MODELS ARE IN GOOD AGREEMENT THAT THE TROUGH WILL MOVE SOUTH OF THE AREA THIS MORNING...BUT IN ITS WAKE THERE WILL BE YET ANOTHER TROUGH /CURRENTLY LOCATED NEAR LAKE WINNIPEG/ AND IT WILL MOVE THROUGH DURING THE AFTERNOON. THE STEEPEST 925 TO 700 MB LAPSE RATES AND SMALL CAPES WILL MOVE EAST INTO WISCONSIN LATE THIS MORNING AND REMAIN ACROSS WISCONSIN THIS AFTERNOON. THIS WAS USED TO DEFINE WHERE RAIN/SNOW SHOWERS WERE PLACED. MEANWHILE IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA...THE TROUGH MAY PRODUCE ENOUGH LIFT FOR SOME SPRINKLES OR FLURRIES. FOR TONIGHT...MODELS CONTINUE TO SHOW THAT A POCKET OF -10C 850 MB AIR WILL MOVE SOUTH INTO THE AREA. BESIDES BEING COLD...THERE IS ALSO QUITE A BIT OF MOISTURE BETWEEN 950 AND 800 MB. THIS WILL KEEP THE AREA MOSTLY CLOUDY. WHILE THERE WILL BE CLOUDS...THE LAPSE RATES WILL BE BE FAIRLY STABLE...SO NOT EXPECTING ANY PRECIPITATION. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 316 AM CDT WED OCT 23 2013 ON THURSDAY...850 MB TEMPERATURES WILL BE AROUND -8C. THIS WILL RESULT IN HIGH TEMPERATURES ONLY CLIMBING TO AROUND 40 DEGREES. DURING THE AFTERNOON...THE 925 TO 700 MB LAPSE RATES BECOME VERY UNSTABLE ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA. THIS WILL LIKELY RESULT IN THE DEVELOPMENT OF FLURRIES AND SPRINKLES ACROSS THIS AREA...SO IT WAS ADDED TO THE FORECAST. WITH THESE STEEP LAPSE RATES CONTINUING INTO THE EVENING...MAY HAVE TO ADD SOME FLURRIES TO THE EVENING FORECAST. ON FRIDAY NIGHT AND SATURDAY...THE MODELS CONTINUE TO SHOW THAT A SHORT WAVE TROUGH WILL MOVE SOUTHEAST ACROSS NORTHEAST MINNESOTA AND EASTERN WISCONSIN. AHEAD OF THIS SYSTEM...DRY AIR WILL BE ADVECTED OFF OF THE PLAINS. THIS WILL PRECLUDE THE DEVELOPMENT OF SHOWERS ALONG THE CANADIAN COLD FRONT. WITH THE EXCEPTION OF THE ECMWF WHICH HAS SOME PRECIPITATION ALONG AND NORTH OF INTERSTATE 94... THE REMAINDER OF THE MODELS ARE DRY ACROSS OUR AREA. WITH MODEL CONSENSUS BEING DRY AND THE MODELS CONTINUING TO TREND THAT WAY... WENT WITH A DRY FORECAST. ON SUNDAY NIGHT...THE MODELS CONTINUE TO SHOW THAT A COLD FRONT WILL MOVE SOUTHEAST THROUGH THE AREA. LIKE THE PREVIOUS ONE...DRY AIR IS ADVECTED AHEAD OF THIS FRONT OFF OF THE PLAINS. AS A RESULT... THE MODELS MOVE THIS FRONT THROUGH THE AREA DRY. FROM MONDAY NIGHT INTO TUESDAY...A LOW PRESSURE SYSTEM WILL MOVE ALONG THE FRONT THAT PAST THROUGH THE AREA DRY ON SUNDAY NIGHT. WEAK 850 MB MOISTURE TRANSPORT WILL BRING MOISTURE BACK NORTHWARD INTO THE AREA. IN ADDITION...THE AREA WILL BE LOCATED IN THE LEFT EXIT REGION OF A 120 KNOT 250 MB JET. THIS WILL GREATLY ENHANCE THE LIFT ACROSS THE REGION. THIS WILL RESULT IN THE DEVELOPMENT OF SHOWERS ACROSS THE AREA. THE ALL BLEND IS ALREADY PRODUCING 40 TO 50 PERCENT CHANCES ACROSS THE REGION. THIS SEEMS REASONABLE SO NOT CHANGES WERE MADE. AT THIS TIME...IT LOOKS LIKE MUCH OF THIS PRECIPITATION WILL BE IN THE FORM OF RAIN. HOWEVER CANNOT RULE OUT SOME SNOW AS THE WAVE EJECTS SOUTHEAST OF THE FORECAST AREA. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING) ISSUED AT 609 AM CDT WED OCT 23 2013 DEEP CYCLONIC FLOW REMAINS IN PLACE ACROSS THE REGION THIS MORNING. THIS FLOW...COMBINED WITH WEAK SHORT WAVE TROUGHS MOVING THROUGH THE FLOW...HAS BEEN ENOUGH TO PRODUCE SOME ISOLATED AREAS OF LIGHT SNOW OR FLURRIES THIS MORNING. CONDITIONS OUTSIDE THE AREAS OF LIGHT SNOW ARE VFR WHILE MVFR CONDITIONS HAVE OCCURRED WITH THE SNOW. BASED ON THE RADAR...KLSE HAS A BETTER CHANCE OF SEEING SOME OF THE LIGHT SNOW THIS MORNING...BUT EVEN THERE CONFIDENCE IS NOT HIGH SINCE IT IS SO ISOLATED IN NATURE. PLAN TO START THE FORECAST WITHOUT ANY MENTION OF SNOW BUT WILL MONITOR AND QUICKLY AMEND IF IT LOOKS LIKE IT WILL HIT KLSE. STEEP LAPSE RATES WILL DEVELOP BY MID MORNING AND WITH THE CYCLONIC FLOW AND LOW LEVEL MOISTURE...THIS SHOULD BE ENOUGH TO CAUSE CEILINGS TO COME DOWN. FOR NOW WILL HOLD THEM AT VFR...BUT SOME OF THE FORECAST SOUNDINGS FROM THE 23.06Z NAM AND 23.09Z RAP SUGGEST THE POTENTIAL TO DROP TO MVFR. CONSIDERABLE UNCERTAINTY ON WHAT WILL HAPPEN AFTER SUNSET. THE NAM AND 23.00Z GFS SOUNDINGS SUGGEST THE CLOUDS COULD SCATTER OUT SIMILAR TO THE LAST TWO NIGHTS BUT FOR NOW...WILL STAY PESSIMISTIC AND CONTINUE THE VFR CEILINGS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04
AREA FORECAST DISCUSSION
NWS ALBANY NY
134 PM EDT WED OCT 23 2013 .SYNOPSIS... COLDER AIR WILL CONTINUE TO MOVE INTO THE REGION OVER THE NEXT FEW DAYS WITH LAKE EFFECT RAIN AND SNOW SHOWERS OFF LAKE ONTARIO AFFECTING THE WESTERN ADIRONDACKS AND WESTERN MOHAWK VALLEY. AREAS OF FROST WILL OCCUR ACROSS THE REGION OVER THE NEXT FEW NIGHTS...AND THE HUDSON VALLEY WILL SEE IT/S FIRST KILLING FREEZE OF THE FALL SEASON THIS WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 130 PM EDT...SOME BREAKS IN THE CLOUDS HAVE DEVELOPED...IN ASSOCIATION WITH A POCKET OF SUBSIDENCE BETWEEN THE LOW PRESSURE SYSTEM ALONG/OFF THE NORTHERN MID ATLANTIC COAST...AND THE UPPER LEVEL TROUGH APPROACHING FROM THE WEST. HAVE RAISED MAX TEMPS ACCORDINGLY...WITH TEMPS REACHING THE LOWER 50S IN MOST VALLEY AREAS...AND MID/UPPER 40S ACROSS MOST HIGHER ELEVATIONS. HOWEVER...ACROSS THE HIGHEST ELEVATIONS ACROSS THE SOUTHERN ADIRONDACKS AND SOUTHERN VT...MAX TEMPS WILL LIKELY ONLY REACH AROUND OR A BIT OVER 40. AS THE TROUGH...BOTH SFC AND ALOFT APPROACH FROM THE WEST LATER THIS AFTERNOON...CLOUDS SHOULD ONCE AGAIN THICKEN/SOLIDIFY...BOTH FROM INCREASING SYNOPTIC LIFT...AND ALSO THERMODYNAMICALLY AS CONVECTIVE TEMPS ARE REACHED. THE LATEST HRRR INDICATED SOME SHOWERS MAY DEVELOP/EXPAND NORTHEASTWARD INTO PORTIONS OF THE REGION LATER THIS AFTERNOON. WILL RAISE POPS A BIT...WITH SOME CHC POPS INDICATED IN MOST AREAS FOR THE PERIOD FROM ROUGHLY 4 PM - 7 PM. THE MOST PERSISTENT SHOWERS THROUGH THIS AFTERNOON WILL BE ACROSS THE SOUTHERN ADIRONDACKS...ESP NORTHERN HERKIMER CO AND NW HAMILTON COS...WHERE SOME LAKE EFFECT SHOWERS WILL OCCUR. SOME WET SNOW AND/OR GRAUPEL WILL LIKELY MIX IN TOWARD SUNSET IN THESE AREAS ABOVE 1800 FT. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... LAKE EFFECT WILL GET GOING ONCE AGAIN TONIGHT OFF LAKE ONTARIO AS THE FLOW ALIGNS IN THE WAKE OF THE SHORTWAVE. WITH 850 HPA TEMPS DROPPING TO -6 DEGREES C...SEVERE INSTABILITY WILL KEEP THE WORST OF THE LAKE ACTIVITY WEST OF OUR CWA...AS SHOWN IN LOCAL CSTAR RESEARCH. AT TIMES...THE LAKE EFFECT MAY REACH INTO THE FAR NORTHWESTERN PARTS OF OUR REGION BETWEEN TONIGHT AND THURSDAY NIGHT. CONSIDERING ITS STILL LATE OCTOBER...THE BOUNDARY LAYER WILL BE WARM ENOUGH TO SUPPORT RAIN AS THE PTYPE DURING THE DAY...ESP WHEN INTENSITY LIGHTENS UP. HOWEVER...PERIODS OF SNOW SHOWERS WILL OCCUR THROUGH THE PERIOD...WITH 1 TO POSSIBLY 4 INCHES OF SNOW. THE HIGHEST AMOUNTS WILL OCCUR AT THE HIGHER ELEVATIONS...WITH HIGH MOUNTAIN VALLEY TOWNS SUCH AS OLD FORGE AND INLET LIMITED TO JUST AROUND AN INCH OR SO OF WET SNOW. THE BAND MAY SHIFT INTO THE WESTERN MOHAWK VALLEY DURING THURSDAY NIGHT...BUT JUST A COATING IS EXPECTED FOR THE MOHAWK VALLEY CITIES OF HERKIMER COUNTY. BY FRIDAY...ANOTHER WEAK SHORTWAVE WILL DISRUPT THE FLOW AND LOWER THE THREAT FOR LAKE EFFECT PRECIP. HOWEVER...THESE FIRST FLAKES OF THE YEAR WILL REMIND EVERYONE THAT THE VERY LONG AND COLD UPSTATE NY/ADIRONDACK WINTER HAS ARRIVED...AND ISN/T GOING AWAY FROM A LONG LONG WHILE. ELSEWHERE...SKIES WILL RANGE FROM PARTLY TO MOSTLY CLOUDY FOR TONIGHT THROUGH FRIDAY NIGHT...WITH THE MOST CLOUDS UP NORTH DOWNWIND OF THE LAKE. BELOW NORMAL TEMPS ARE EXPECTED WITH UPPER 20S TO MID 30S AT NIGHT...AND 40S TO LOW 50S DURING THE DAYTIME. AREAS OF FROST WILL OCCUR...AND ADDITIONAL FROST/FREEZE HEADLINES MAY BE NEEDED FOR THE HUDSON VALLEY DEPENDING ON JUST HOW CHILLY THIS MORNING/S LOW ARE /TO DETERMINE IF THE GROWING SEASON HAS ENDED IN ANY ZONES OR NOT/. && .LONG TERM /SATURDAY THROUGH TUESDAY/... MODEL GUIDANCE IN IS GOOD AGREEMENT THAT A VIGOROUS SHORT WAVE WILL DIVE INTO THE LONGWAVE TROUGH OVER THE WEEKEND. A SURFACE LOW PRESSURE SYSTEM WILL ACCOMPANY THIS FEATURE MOVING ACROSS THE GREAT LAKES REGION SATURDAY AND ACROSS EASTERN CANADA AND THE NORTHEAST SUNDAY. THE SYSTEM WILL QUICKLY MOVE ACROSS THE REGION BRINGING SOME RAIN AND SNOW SHOWERS TO THE AREA...THE BETTER CHANCES WILL BE TO THE NORTH AND WEST OF THE CAPITAL DISTRICT. TEMPERATURES WILL CONTINUE TO RUN BELOW NORMAL BY AROUND 10 DEGREES WITH HIGHS ONLY RANGING FROM THE UPPER 30S ACROSS THE WESTERN ADIRONDACKS INTO THE LOWER 50S IN THE MID HUDSON VALLEY ON SATURDAY AND SUNDAY. TEMPERATURES WILL MODERATE AS WE HEAD INTO NEXT WEEK AS THE PATTERN CHANGES AS A TROUGH DIGS ACROSS THE WESTERN UNITED STATES/ROCKIES AND THE FLOW OVER THE NORTHEAST BECOME SOUTHWESTERLY AN ANOTHER LOW PRESSURE SYSTEM APPROACHES. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... VFR FLYING CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AS CLOUDS AND SCATTERED LIGHT SHOWERS ASSOCIATED WITH AN UPPER-LEVEL DISTURBANCE MOVE ACROSS THE REGION. THIS AFTERNOON...INITIAL POCKETS OF CLEARING IN SKY COVER EARLY THIS AFTERNOON WILL GIVE WAY TO BROKEN-OVERCAST MIDLEVEL CLOUDS AS A PIECE OF UPPER-LEVEL ENERGY MOVES ACROSS THE REGION. THIS ENERGY WILL HELP DEVELOP SOME SCATTERED LIGHT SHOWERS AFTER 20Z THIS AFTERNOON AND HAVE PLACED VCSH IN THE TAFS BETWEEN 20Z-00Z. WINDS THIS AFTERNOON WILL BE LIGHT GENERALLY LESS THAN 10 KNOTS. TONIGHT INTO THURSDAY...CLOUDS WILL GENERALLY DECREASE ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA TONIGHT AS THE UPPER-LEVEL ENERGY EXITS TO THE EAST RESULTING IN MAINLY CLEAR SKIES AT KPOU AND KPSF. FURTHER NORTH...CYCLONIC FLOW OFF LAKE ONTARIO WILL RESULT IN LAKE-ENHANCED CLOUDS AT KGFL AND KALB. HAVE INTRODUCED MVFR FLYING CONDITIONS AT KPOU AS CONDITIONS MAY BECOME BRIEFLY FAVORABLE FOR PATCHY FOG/LOW STRATUS BETWEEN 09Z-12Z. SCATTERED TO BROKEN STRATOCUMULUS WILL RETURN DURING THE DAY THURSDAY. WESTERLY WINDS WILL BE GUSTY BETWEEN 10-20 KNOTS...WITH GUSTS UP TO 25 KNOTS POSSIBLE. OUTLOOK... THU NIGHT-FRI NIGHT: NO OPERATIONAL IMPACT. NO SIG WX. SAT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA. SAT NIGHT-SUN: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. SUN NIGHT-MON: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... LOW PRESSURE WILL TRACK WELL OFFSHORE WHILE AN UPPER LEVEL DISTURBANCE MOVES ACROSS THE REGION WITH A FEW SHOWERS AND PLENTY OF CLOUDS. WEST TO NORTHWEST WINDS WILL BE AROUND 5 TO 10 MPH. RH VALUES WILL ONLY DROP TO 45 TO 65 PERCENT THIS AFTERNOON. RH VALUES WILL RETURN TO NEAR 100 PERCENT TONIGHT WITH DEW AND FROST FORMATION. WINDS WILL BE LIGHT OVERNIGHT. SOME LAKE EFFECT RAIN AND SNOW WILL AFFECT THE ADIRONDACKS AND WESTERN MOHAWK VALLEY. RH VALUES WILL DROP TO 35 TO 60 PERCENT TOMORROW...WITH THE HIGHEST VALUES ACROSS NORTHWESTERN PARTS OF THE REGION...WHERE SOME LAKE EFFECT RAIN AND SNOW SHOWERS ARE POSSIBLE. WEST WINDS WILL BE STRONG AT 10 TO 25 MPH WITH A FEW HIGHER GUSTS. && .HYDROLOGY... NO HYDRO ISSUES ARE ANTICIPATED OVER THE NEXT FIVE DAYS. RIVER AND STREAM LEVELS REMAINS NEAR TO SLIGHTLY BELOW NORMAL FOR MID OCTOBER. MOST PARTS OF THE AREA WILL SEE LITTLE PRECIPITATION FOR THE REMAINDER OF THE WEEK. THE EXCEPTION MAY BE ACROSS THE WESTERN ADIRONDACKS AND WESTERN MOHAWK VALLEY...WHERE SOME LAKE EFFECT RAIN AND SNOW SHOWERS WILL BE POSSIBLE. ANY PRECIPITATION WILL HAVE LITTLE TO NO EFFECT ON AREA RIVERS AND STREAMS. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...FRUGIS NEAR TERM...KL/IRL/FRUGIS SHORT TERM...FRUGIS LONG TERM...IAA AVIATION...IAA/IRL FIRE WEATHER...FRUGIS HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
650 PM EDT WED OCT 23 2013 .SYNOPSIS... HIGH PRESSURE AND A MUCH DRIER AIR MASS WILL MOVE INTO THE AREA TONIGHT AND THEN PERSIST THROUGH THURSDAY. AN ARCTIC-LIKE COLD FRONT WILL MOVE THROUGH ON FRIDAY WITH A LARGE AREA OF COOL HIGH PRESSURE ENCOMPASSING THE REGION BEHIND IT. HIGH PRESSURE WILL REMAIN THE DOMINANT FEATURE THROUGH EARLY NEXT WEEK ALTHOUGH TEMPERATURES WILL BEGIN TO MODIFY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... A CONSIDERABLY DRIER AND COOLER AIRMASS CONTINUES TO ADVECT INTO THE REGION THIS EVENING IN THE WAKE OF A COLD FRONT. HIGH PRESSURE IS FORECAST TO MOVE INTO WEST-CENTRAL GEORGIA BY SUNRISE... ALLOWING FOR A GRADUAL RELAXING OF THE PRESSURE GRADIENT. SHOULD SEE MODEST RADIATIONAL PROCESSES TAKE HOLD AS A RESULT... ESPECIALLY ACROSS INTERIOR SOUTHEAST GEORGIA WHERE THE BOUNDARY LAYER COULD COMPLETELY DECOUPLE. LOWS FROM THE UPPER 30S ACROSS THE HIGHER TERRAIN OF JENKINS-SCREVEN-ALLENDALE COUNTIES TO THE UPPER 40S/LOWER 50S AT THE BEACHES LOOK ON TARGET FOR NOW. IT SHOULD BE NOTED THAT THE 23/18Z GFS BASED COOP GUIDANCE SHOWS A FEW LOCATIONS SUCH AS SYLVANIA...ALLENDALE AND RIDGEVILLE DROPPING TO 36/35/34 DEGREES RESPECTIVELY. GIVEN THIS IS THE REAL FIRST DOSE OF COLD AIR FOR THE FALL SEASON...IT IS UNCLEAR HOW GUIDANCE IS PERFORMING WITH THIS AIRMASS. WILL CERTAINLY MONITOR THERMAL TRENDS CLOSELY THIS EVENING AS ANY LOWERING WILL OPEN UP THE POSSIBILITY FOR SOME PATCHY FROST. FINALLY...THERE COULD BE SOME MESOSCALE LAKE INFLUENCES IN THE MONCKS CORNER AREA OVERNIGHT. WITH A LIGHT NORTH TO NORTHWEST FLOW EXPECTED TO PERSIST...THIS MAY BE JUST ENOUGH TO ADVECT WARMER AIR FROM OFF LAKE MOULTRIE INTO THE CITY. MAY NEED TO ADJUST TEMPERATURES UP A FEW THERE WITH THE LATE EVENING UPDATE. THE FOLLOWING CHANGES WERE MADE FOR THE EARLY EVENING UPDATE... 1. ADJUSTED HOURLY DEWPOINTS SLIGHTLY ACROSS COASTAL GEORGIA WHERE DEWPOINTS HAVE BEEN SLOWER TO FALL TODAY. 2. ADJUSTED WIND SPEEDS SLIGHTLY PER GOING TRENDS. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... THURSDAY...THE AREA WILL REMAIN UNDER ZONAL FLOW WITH WNW WINDS OF 20-25 KT AROUND 850 MB. COLD ADVECTION WILL CONTINUE AS A 1025 MB HIGH PRESSURE SYSTEM SHIFTS SOUTHEAST TOWARD THE SOUTHEAST STATES. ANOTHER DAY OF CLEAR SKIES AND DRY AIR WILL OCCUR...WITH HIGH TEMPERATURES AROUND 70 DEGREES. COOL TEMPS IN THE LOWER TO MIDDLE 40S EXPECTED THURSDAY NIGHT AS WEAK COLD ADVECTION CONTINUES. AN ARCTIC-LIKE FRONT WILL DROP SOUTH THROUGH THE AREA FRIDAY MORNING WITH AN EXPANSIVE COLD...DRY 1028 MB HIGH OVERSPREADING THE EASTERN UNITED STATES. THE DOWNSLOPE INFLUENCE WEAKENS ON FRIDAY SO THERE WILL BE LESS IN THE WAY OF COMPRESSIONAL HEATING TO OFFSET THE COLD ADVECTION. THUS HIGH TEMPS WILL ONLY REACH THE MIDDLE 60S IN SOUTHERN SC AND UPPER 60S IN SOUTHEAST GA. FRIDAY NIGHT LOOKS TO BE THE COLDEST OF THE SEASON THUS FAR. COLD HIGH PRESSURE SETTLING OVER THE AREA WITH CLEAR SKIES AND FAIRLY LIGHT WINDS WILL ALLOW TEMPERATURES TO PLUMMET AFTER SUNSET. WE LOWERED TEMPERATURES A FEW DEGREES...WITH READINGS AS LOW AS 34 DEGREES FAR INLAND TO AROUND 40 IN THE BELT CLOSER TO THE COAST. GEOSTROPHIC WINDS WILL BE LESS THAN 15 KT OVERNIGHT...A BIT LOWER FARTHER INLAND AS THE GRADIENT BECOMES LESS TIGHT. WITH OVERNIGHT DEWPOINTS RANGING FROM 28-31...THERE STANDS A DECENT CHANCE THAT SOME OF OUR RURAL INLAND ZONES MAY EXPERIENCE SCATTERED FROST SO WE WILL INCLUDE THIS POSSIBILITY IN THE HAZARDOUS WEATHER OUTLOOK. DESPITE SUNNY SKIES...SATURDAY WILL REMAIN COOL DUE TO THE COLD AIRMASS IN PLACE SO HIGH TEMPS WILL ONLY REACH THE MIDDLE 60S. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... FORECAST CONFIDENCE IN THE LONG TERM PERIOD CONTINUES TO BE GOOD. OVERALL THE PERIOD WILL BE QUIET WITH SURFACE HIGH PRESSURE BEING THE PRIMARY FEATURE. WEAK HIGH PRESSURE WILL COVER THE AREA FOR THE LATTER PART OF THE WEEKEND AND INTO MONDAY. THIS WEAK PRESSURE PATTERN WILL THEN EVENTUALLY BE REPLACED BY LOW LEVEL NORTHEAST FLOW AS A STRONGER 1035 MB SURFACE HIGH BUILDS IN NORTHEAST OF THE REGION BY TUESDAY. WE MAY SEE A SUBTLE COASTAL TROUGH DEVELOP OFFSHORE AND GENERATE A FEW SHOWERS OVER THE WATERS...BUT LAND AREAS WILL REMAIN DRY. TEMPS WILL GRADUALLY MODERATE BY EARLY NEXT WEEK...WITH HIGHS IN THE MID 70S AND LOWS IN THE LOW/MID 50S. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... NO CONCERNS. EXTENDED AVIATION OUTLOOK...BREEZY CONDITIONS FRIDAY. && .MARINE... TONIGHT...EXPANDED FLAGS INTO ALL NEARSHORE LEGS. HIGHER RESOLUTION RAP AND H3R MODELS SHOW A STRONGER...SECONDARY WIND SURGE WORKING DOWN THE COAST THIS EVENING AS ANOTHER PUSH OF COLD AIR ADVECTION MOVES THROUGH. SHOULD SEE AT LEAST FREQUENT GUSTS TO 25 KT THROUGH ABOUT 2 AM. SEAS WILL RANGE FROM 2-4 FT NEARSHORE WATERS TO 4-5 FT OFFSHORE WATERS. THURSDAY THROUGH SUNDAY...CONDITIONS WILL START OUT RELATIVELY QUIET ON THURSDAY AS WEAKER HIGH PRESSURE SITS ACROSS THE REGION. THIS WILL CHANGE ON FRIDAY AS A STRONG COLD FRONT PUSHES THROUGH THE REGION. MUCH COOLER AIR WILL RUSH ACROSS THE WARMER WATERS...AND GOOD MIXING PROFILES WILL DEVELOP. NORTHWEST TO NORTH WINDS WILL STEADILY STRENGTHEN THROUGH THE DAY FRIDAY AND ESPECIALLY DURING THE EVENING HOURS. WE CURRENTLY SHOW WINDS/SEAS JUST BELOW SMALL CRAFT ADVISORY THRESHOLDS THOUGH A BRIEF PERIOD OF ADVISORY CONDITIONS IS POSSIBLE ON THE OFFSHORE GA WATERS LATE FRIDAY INTO FRIDAY NIGHT. CONDITIONS WILL IMPROVE SATURDAY INTO SUNDAY AS HIGH PRESSURE REMAINS IN CONTROL AND THE PRESSURE GRADIENT RELAXES. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT THURSDAY FOR AMZ350-352- 354-374. && $$ ST/ECT
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
248 PM CDT WED OCT 23 2013 .DISCUSSION... 246 PM CDT WELL BELOW AVERAGE MID/UPPER LEVEL HEIGHTS AND TEMPERATURES WILL CONTINUE ACROSS MUCH OF THE EASTERN HALF OF THE CONUS THROUGH AT LEAST EARLY NEXT WEEK. THE PERSISTENT UPPER RIDGING OVER THE WESTERN CONUS CONTINUES TO BUCKLE THE JET STREAM FROM NORTHWESTERN CANADA SOUTH-SOUTHEASTWARD ACROSS REGION...AND THIS CONTINUES TO STEER NUMEROUS PERTURBATIONS WITHIN THE LARGER SCALE FLOW PATTERN RIGHT ACROSS THE AREA. ALTHOUGH NO BIG PRECIP EVENTS ARE EXPECTED WITH THIS DISTURBANCES...THEY WILL ACT TO BRING REINFORCING SHOTS OF COLD AIR AND CLOUD COVER TO THE REGION THROUGH FRIDAY. THEREFORE THE MAIN FORECAST CONCERNS IN THE SHORT TERM PERIOD WILL BE WITH TEMPERATURES AND CLOUD COVER TRENDS. REGIONAL SATELLITE IMAGERY EARLY THIS AFTERNOON INDICATES A GOOD DEAL OF CLOUD COVER UPSTREAM ACROSS THE UPPER MIDWEST AND SOUTHERN CANADA. HOWEVER...THERE ARE ALSO QUITE A FEW HOLES IN THE EXTENSIVE CLOUD COVER. THEREFORE...ALTHOUGH IT APPEARS THERE WILL BE CLOUD COVER ACROSS THE REGION FOR THE NEXT COUPLE OF NIGHTS...IT ALSO APPEARS THAT THERE COULD BE A COUPLE PERIODS OF CLEAR TO PARTLY CLOUDY SKIES DURING THE NIGHT...ESPECIALLY THURSDAY NIGHT. THIS CLOUD COVER DEFINITELY DECREASES THE CONFIDENCE IN HOW LOW TEMPERATURES WILL DROP BOTH TONIGHT AND THURSDAY NIGHT. HOWEVER...WITH SURFACE COLD HIGH PRESSURE DOMINATING ACROSS THE PLAINS AND MISSOURI RIVER VALLEY THROUGH FRIDAY...OVERNIGHT LOW TEMPERATURES COULD EASILY DROP INTO THE LOW 20S IN SOME OF THE CLIMATOLOGICAL FAVORED AREAS OF NORTHERN ILLINOIS IF SKY COVER COOPERATES. A GOOD DEAL OF STRATOCU HAS DEVELOPED AHEAD OF THE MAIN AREA OF STRATUS WITH STEEP LOW LEVEL LAPSE RATES IN PLACE THIS AFTERNOON. THERE ARE EVEN A FEW LIGHT SHOWERY RETURNS SHOWING UP ON THE REGIONAL RADAR. THEREFORE...THERE COULD BE A FEW ISOLATED SHOWERS OR SNOW FLAKES THIS AFTERNOON...MAINLY TO THE NORTH OF INTERSTATE 80. THERE COULD EVEN BE SOME GRAUPEL IN SOME OF THE STRONGER UPDRAFTS GIVEN THE DEEP OF THE UNSTABLE LAYER REACHING CLOSE TO -15 CELSIUS. THIS SHOWER ACTIVITY SHOULD ABATE QUICKLY THIS EVENING. IN ADDITION TO THE CLOUD COVER AND SHOWERY ACTIVITY...A MID LEVEL PERTURBATION IN THE LARGER SCALE FLOW PATTERN...IS INDUCING A WEAK BAND OF FRONTOGENESIS ALONG THE BAROCLINIC ZONE TO THE WEST OF THE AREA ACROSS WESTERN AND CENTRAL SECTIONS OF IOWA THIS AFTERNOON. THIS DISTURBANCE SHOULD PROGRESS EAST-SOUTHEASTWARD ACROSS CENTRAL SECTIONS OF ILLINOIS TONIGHT...AND THIS COULD RESULT IN A FEW LIGHT RAIN/SNOW SHOWERS ACROSS MY FAR SOUTHERN COUNTIES LATER TONIGHT. THEREFORE...I DID ADD A SLIGHT CHANCE MENTION FOR THESE AREAS LATE TONIGHT AND EARLY TOMORROW. COLD AIR ADVECTION CONTINUES INTO THURSDAY...SETTING UP AN EVEN COLDER THERMAL PROFILE ACROSS THE AREA THAN TODAY. TEMPERATURES AT 850 AND 925 MB ARE PROGGED TO DROP TO NEAR -8 AND -2 DEGREES CELSIUS...RESPECTIVELY. THIS WILL LIKELY ONLY YIELD HIGH TEMPERATURES IN THE LOWER 40S ON THURSDAY IN MOST AREAS...EVEN UNDER PARTLY SUNNY SKIES. AS STATED IN THE PREVIOUS DISCUSSION...TEMPERATURES OF THESE MAGNITUDES AT 850 MB ARE QUITE RARE THIS TIME OF YEAR...WITH -10 ABOUT THE COLDEST EVER REPORTED FROM THE KDVN AND KILX RAOBS DURING OCTOBER. AFTER THE GOOD POTENTLY FOR A VERY COLD NIGHT ACROSS THE AREA THURSDAY NIGHT...IT APPEARS THINGS WILL BEGIN TO WARM ACROSS THE REGION LATER FRIDAY AND INTO EARLY SATURDAY. ANOTHER POTENT CLIPPER SYSTEM IS EXPECTED TO DEVELOP AND TRACK ACROSS THE UPPER GREAT LAKES LATE FRIDAY AND SATURDAY. THIS SHOULD INDUCE SOME GUSTY SOUTHWESTERLY FLOW ACROSS THE REGION DURING THE DAY FRIDAY...AND THIS WILL ULTIMATELY PUSH THE BAROCLINIC ZONE BACK EAST ACROSS THE AREA...SETTING UP A WARMING PERIOD. UNFORTUNATELY...THIS WARMER PERIOD WILL BE SHORT LIVED...AS THE COLD FRONT...ASSOCIATED WITH THE CLIPPER SYSTEM...COMES ACROSS THE AREA ON SATURDAY...WITH COLDER AIR RETURNING. DUE TO THE TRACK OF THIS CLIPPER SYSTEM...IT IS UNLIKELY THAT WE WILL GET ANY PRECIP FROM IT...THEREFORE I HAVE CONTINUED THE DRY FORECAST FOR THIS PERIOD. DEPENDING ON THE TIMING OF THE FRONT ON SATURDAY...AREAS ACROSS MY SOUTHERN CWA COULD APPROACH 60 DEGREES BEFORE THE COLD FRONT PUSHES THROUGH. FOLLOWING THIS SYSTEM...UNCERTAINTY BEGINS TO INCREASE...ESPECIALLY NEXT WEEK. IT APPEARS THAT THE FLOW PATTERN WILL UNDERGO A SHIFT...WITH A GOOD POTENTIAL OF A SYSTEM DIGGING IN ACROSS THE INTER-MOUNTAIN WEST. THIS COULD SUPPORT AN INCLEMENT WEATHER PATTERN FOR THE CENTRAL CONUS FOR MUCH OF THE MIDDLE OF NEXT WEEK...WITH SEVERAL CHANCES OF RAIN. THERE CONTINUES TO BE UNCERTAINTIES ON THE TIMING OF THE SYSTEM...SO I HAVE CAPPED POPS AT 50 PERCENT UNTIL THE MODELS AND ENSEMBLES COME TO BETTER AGREEMENT. TEMPERATURES DURING THE PERIOD WILL ALSO BE DEPEND ON WHERE THE SURFACE WARM FRONT SETS UP NEXT WEEK. OVERALL...THIS SYSTEM DOES HAVE THE POTENTIAL TO BRING SOME DECENT RAINFALL AMOUNTS TO THE AREA NEXT WEEK. KJB && .CLIMATE... RECORD LOW TEMPERATURES IN OUTLYING AREAS MAY BE APPROACHED OR SET FRIDAY MORNING IF CLOUDS DEPART AS FORECAST. FOR CHICAGO...THE CLIMATE PERIOD OF RECORD INCLUDES SOME COLDER YEARS IN THE 1880S...WITH THE RECORD LOW BEING IN THE TEENS WHICH WILL VERY LIKELY NOT BE APPROACHED AT OHARE. BUT FOR OUR OTHER LONG TERM CLIMATE SITE OF ROCKFORD WHICH DATES BACK TO 1905...IT IS VERY POSSIBLE. RECORD LOW FOR ROCKFORD ON OCTOBER 25TH: 23 (1987) MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LOWER END VFR CIGS DEVELOPING THIS AFTERNOON. * SCT -SHSN POSSIBLE. LASTING IMPACT NOT LIKELY. KREIN //DISCUSSION...UPDATED 20Z... THE REGION WILL REMAIN UNDER WNWLY-NWLY FLOW AS HIGH PRESSURE STRETCHES FROM THE NRN PLAINS TO THE LOWER MS VLY AND DEEP LOW PRESSURE CONTINUE TO LIFT NE THROUGH NRN QUEBEC. DAYTIME MIXING UNDER MOSTLY SUNNY SKIES...AT LEAST INITIALLY...WILL BRING SOME HIGHER GUSTS DOWN TO THE SFC...IN THE 15-20KT RANGE. LATEST SATELLITE IMAGERY SHOWS A THINNING ST DECK BEING REPLACED BY A CU/STRATOCU DECK...AND CLOUD COVERAGE SHOULD INCREASE THROUGH THE AFTERNOON. RFD WILL HAVE THE BEST CHANCE TO SEE THE POTENTIAL FOR CIGS TO DROP IN THE HIGHER END MVFR RANGES...AT THIS POINT...EXPECT THAT CIGS OVER THE ERN TERMINALS SHOULD REMAIN VFR...THROUGH A BRIEF PERIOD OF MVFR CIGS IS NOT OUT OF THE QUESTION THROUGH THE AFTERNOON. WITH THE CLOUD CHARACTER BECOMING MORE CONVECTIVE THROUGH THE AFTERNOON...SCT -SHSN HAVE DEVELOPED. THE LOW LEVELS REMAIN FAIRLY DRY...SO DO NOT EXPECT ANY ACCUMULATING SNOW AND WITH FAST FLOW...ANY -SHSN IMPACTING THE TERMINALS WILL BRIEF. CLOUD COVERAGE WILL DISSIPATE WITH SUNSET...BUT A MODEST PRESSURE GRADIENT WILL KEEP WINDS IN THE 5-10KT RANGE OVERNIGHT. //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MODERATE CONFIDENCE THAT DEVELOPING CIGS WILL REMAIN VFR...THOUGH THERE IS A CHANCE FOR CIGS TO DROP TO HIGHER END MVFR THIS AFTERNOON. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. * MODERATE TO HIGH CONFIDENCE THAT ANY PCPN OCCURRING AT THE TERMINALS WILL BE BRIEF AND HAVE MINIMAL IMPACT. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...CHANCE OF SHRA...MVFR POSSIBLE OVERNIGHT. TUESDAY...CHANCE OF SHRA...MVFR POSSIBLE. JEE && .MARINE... 210 PM CDT GALE POTENTIAL FRIDAY NIGHT AND SATURDAY MORNING IS THE MAIN CONCERN THIS FORECAST PERIOD. A STEADY PRESSURE GRADIENT REMAINS ACROSS THE WESTERN LAKES AS LOW PRESSURE DEEPENS OFF THE ATLANTIC COAST AND ONE AREA OF HIGH PRESSURE OVER WESTERN MISSOURI AND ARKANSAS DRIFTS SOUTHEASTWARD. A WEAK LOW IS MOVING ACROSS THE CENTRAL AND SOUTHERN PLAINS BEHIND THE HIGH BUT WILL BE FADING INTO THIS EVENING. ANOTHER HIGH IS MOVING SOUTHEAST FROM SOUTHERN ALBERTA AND SASKATCHEWAN WILL REACH THE LOWER OHIO VALLEY AND POINTS SOUTHEAST THURSDAY AND THURSDAY NIGHT. THE BAND OF CONVERGENT WINDS SEEN ALONG MUCH OF THE EASTERN SHORE OF THE LAKE ACROSS THE SOUTHERN HALF OF LOWER MICHIGAN WILL DIMINISH INTO THE EVENING ALLOWING A MORE UNIFORM NORTHWEST WIND AND WAVE DIRECTION TO SET UP THERE. THIS WILL LEAD TO BUILDING WAVES AS THE EASTERLY WIND COMPONENT DIMINISHES. OTHERWISE 15 TO 25 KT NORTHWEST WINDS WILL PERSIST THROUGH FRIDAY MORNING THOUGH THERE MAY BE FLUCTUATIONS BETWEEN THE LOWER AND UPPER PORTIONS OF THAT RANGE WHICH WILL BE DIFFICULT TO TIME AS SUBTLE WEAKNESSES IN THE PRESSURE GRADIENT MOVER ACROSS. THIS MAY LEAD TO SOMEWHAT LOWER WAVES AT TIMES. WILL KEEP THE SMALL CRAFT ADVISORY GOING FOR THE INDIANA NEARSHORE WATERS AS-IS FOR NOW AND WILL EVALUATE CANCELLING THE IL SIDE EARLIER BUT DETERMINE THAT JUST BEFORE ISSUANCE TIME THIS AFTERNOON. AS MENTIONED...FRIDAY AFTERNOON THROUGH SATURDAY IS THE MAIN PERIOD OF CONCERN. HIGH PRESSURE WILL BE MOVING SOUTHEAST ACROSS THE OHIO AND LOWER MISSISSIPPI RIVER VALLEYS WHILE AN ALBERTA CLIPPER DROPS SOUTHEASTWARD TOWARDS THE REGION. THE ASSOCIATED SURFACE LOW IS EXPECTED TO DEEPEN ACROSS NORTHERN LAKE SUPERIOR FRIDAY EVENING AS THE TRACK TURNS EASTERLY WITH THE LOW CENTER LOOKING TO REMAIN NORTH OF LAKE MICHIGAN. STRONG LOW AND MID LEVEL SOUTHWESTERLY WINDS WILL DEVELOP THROUGH THE DAY FRIDAY WITH UNSTABLE CONDITIONS REMAINING OVER THE LAKE THANKS TO THE STILL COLD AIRMASS. SOUTHWEST GALES LOOK TO DEVELOP FRIDAY EVENING AHEAD OF THE LOW WITH A PEAK INTENSITY LATE FRIDAY EVENING AND EARLY SATURDAY AS THE LOW PASSES BRINGING A COLD FRONT ACROSS THE LAKE. THIS WILL TURN WINDS WESTERLY BY SATURDAY MORNING AND NORTHWESTERLY THROUGH THE DAY. THIS TYPE OF SYSTEM IS CERTAINLY CAPABLE OF GALES BUT DO HAVE A FEW CONCERNS REGARDING POTENTIAL INTENSITY. GUIDANCE HAS HAD A HARD TIME WITH THESE SYSTEMS OF LATE BUT THIS ONE LOOKS TO BE ONE OF THE BETTER ORGANIZED AND TYPICAL TYPE CLIPPERS WE HAVE SEEN SO HAVE BETTER CONFIDENCE IN THEIR ABILITY TO PROVIDE REASONABLE OUTPUT. GIVEN THE STRENGTH OF THE LOW AND DEPARTING HIGH AHEAD OF IT LOW LEVEL WINDS COULD BECOME QUITE STRONG WITH MIXING DEPTH BEING KEY IN DETERMINING PEAK WINDS. TIMING MAY NEED TO BE ADJUSTED SOMEWHAT BUT RIGHT NOW FRIDAY EVENING AND FRIDAY NIGHT LOOK TO BE THE WORST PERIODS WITH SOME POSSIBILITY THAT 40-45 KT SOUTHWEST WINDS MAY OCCUR FOR AT LEAST A BRIEF PERIOD. THIS WILL HINGE ON THE EXACT TRACK AND INTENSITY OF THE LOW SO WILL STAY ON THE LOWER END OF GALES FOR NOW. SPEEDS WILL GRADUALLY EASE INTO SATURDAY NIGHT AS HIGH PRESSURE QUICKLY MOVES FROM THE NORTHERN ROCKIES TO SOUTHERN PLAINS. A RIDGE AXIS WILL BRIEFLY MOVE ACROSS THE LAKE BRINGING A LULL IN WINDS SOMETIME SUNDAY. FORECAST CONFIDENCE DROPS OFF EARLY NEXT WEEK AS THE UPPER FLOW PATTERN ATTEMPTS TO SHIFT. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM WEDNESDAY. && $$ 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 237 PM CDT Wed Oct 23 2013 .DISCUSSION... ISSUED 235 PM CDT Wed Oct 23 2013 Forecast concerns today is the light precipitation (pcpn) this evening, the hard freeze on Thursday night, and then the pattern change and pcpn early next week. SHORT TERM...Tonight through Friday night. Upper level flow remains northwest over midwest with large upper trough over eastern US. Strong upper jet of 100kts+ from Dakotas into IL/In. Jet max in this strong jet flow bringing channeled vorticity (seen in moisture channel data), with the resultant cloudiness moving down toward the ILX area again for tonight. Expect therefore the clouds to again spread over region tonight. This will bring a slight chance of rain this evening over the southern half of area. Because of the cloud cover, have raised overnight lows tonight some, staying in the 30s. Major high pressure then builds in for late Thursday, Thursday night and Friday morning. With clear skies, light winds, soundings show this to be the coldest night with temperatures well into the mid 20s. Will go with freeze warning for entire CWA, as the freezing temperatures were not widespread in previous nights, just in patchy areas. LONG TERM...Saturday through Wednesday. In the extended, another cold front comes down through the state by late Saturday, ending the brief warming and bringing more cool in into the area. Do to a lack of moisture, this system will come through dry. Starting Sunday however, the upper level pattern will begin to change, becoming more zonal and the upper trough shifting more to the west. However, with this shift, the models are still in some disagreement on how it will translate. Southerly low level flow will advect into Il, starting a flow of moisture on Monday. A stationary/warm front is expected to develop over the central plains into the Great Lakes, with rain along this frontal zone. The chance of rain will begin Monday night and last into Wednesday. At issue though, is still the exact position of the front and therefore there is still some disagreement on the temperatures and amount of pcpn. Goetsch && .AVIATION... ISSUED 1242 PM CDT Wed Oct 23 2013 VFR conditions will prevail through the afternoon into the evening, before lower clouds associated with an approaching upper-level disturbance arrive tonight. Latest surface analysis shows weak low pressure over northwest Iowa, with light rain/snow falling across much of western Iowa. This system is expected to track southeastward and weaken as it comes into Illinois tonight. Little or no precip is expected as it moves through the area: however, the HRRR indicates ceilings lowering into the MVFR category once wave passes. Based on this, have introduced MVFR ceiling of around 2500ft at KPIA by 05z, then further southeast to KDEC and KCMI by 07z. After that, main question will be when (or if) clearing will occur. GFS insists that skies will begin to clear late tonight into Thursday morning, while NAM generally keeps things overcast. Given what happened with the last passing system last night and the current upstream satellite imagery, will trend toward the more pessimistic NAM. Will maintain cloud cover through the remainder of the forecast, but will raise ceilings back to VFR after 14z. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING from 1 AM to 9 AM CDT Friday FOR ILZ027>031- 036>038-040>057-061>063-066>068-071>073. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
229 PM CDT WED OCT 23 2013 .DISCUSSION... 327 AM CDT AFTER LOOKING LIKE EARLY WINTER YESTERDAY IT WILL CONTINUE TO FEEL AS SUCH FOR A COUPLE DAYS...WITH THE FORECAST CHALLENGES TIED TO WELL BELOW NORMAL TEMPERATURES THESE NEXT FEW DAYS AND THEN SWINGING BACK TO CLOSER TO NORMAL THIS WEEKEND AND MAYBE MORE SO INTO EARLY NEXT WEEK. SYNOPSIS...THE PESKY CLIPPER SYSTEM FROM YESTERDAY IS RACING EASTWARD ACROSS THE UPPER OHIO VALLEY EARLY THIS MORNING. IN ITS WAKE 70M HEIGHT FALLS WERE OBSERVED AT 500MB LAST EVE AS THE LARGE SCALE LONG WAVE TROUGH ACROSS EASTERN/CENTRAL NORTH AMERICA CONTINUES TO BE RE-ESTABLISHED. THAT WILL REMAIN THE DOMINANT INFLUENCE ON THE LOCAL WEATHER PATTERN THIS WEEK...WITH PERSISTENT UPPER LEVEL NORTHWEST FLOW. A SERIES OF MID-LEVEL PERTURBATIONS WILL TRAVERSE IN THIS FLOW TODAY AND TONIGHT...AGAIN FURTHER LEADING TO LOWERED HEIGHTS AND COLD ADVECTION. WITH HIGH PRESSURE REMAINING ACROSS THE CENTRAL PLAINS ALLOWING FOR NO RETURN LOW-LEVEL FLOW...THIS ENABLES AN IDEAL REGIME FOR TEMPERATURES TO REMAIN COLD BY MID-AUTUMN STANDARDS. EARLY THIS MORNING...LOW-LEVEL CONVERGENCE OVER THE LAKE HAS BEEN NOTED IN OBSERVATIONS AND EARLIER WAS ANALYZED FROM MID-LAKE INTO PORTER COUNTY. BUT THIS HAS SHIFTED EAST AND MOST OF THE DEVELOPMENT IS MOVING SOUTHEAST FROM IT...SO ALL IN ALL MOST IF NOT ALL OF PORTER COUNTY LOOKS TO REMAIN FREE OF THE CONVECTIVE SHOWERS OVER THE LAKE THIS MORNING. TODAY AND TONIGHT...MULTIPLE COMPACT AND SHEARED SHORT WAVES ARE NOTED ON THE CYCLONIC SIDE OF THE STRONG UPPER JET FROM MANITOBA INTO THE CORN BELT. UPSTREAM RADAR IMAGERY AND OBSERVATIONS ACROSS MN HAVE INDICATED SOME SNOW SHOWERS WITH THESE. ADD TO THAT SOME MORNING SUNSHINE ACROSS PARTS OF OUR CWA...AND WE SHOULD QUICKLY DESTABILIZE IN THE IMMEDIATE LOW-LEVELS UNDER THESE FEATURES. NAM AND RAP FORECAST BUFR SOUNDINGS FOR OUR FORECAST NOON TEMPS BOTH YIELD ALMOST 100 J/KG OF CAPE. WET BULB ZEROS WERE ANALYZED ON LAST NIGHTS RAOBS AND FORECAST BY TODAYS SOUNDINGS TO BE ONLY AROUND 1000 FT AGL. SO WOULD EXPECT ANY ISOLATED DEVELOPMENT TO BE MAINLY SNOW SHOWERS/FLURRIES. ITS POSSIBLE A COUPLE OF THESE PRODUCE BRIEF MODERATE RATES...BUT WOULD BE VERY TEMPORARY LASTING. HIGHS TODAY SHOULD BE LOWER TO MID 40S BASED ON CLIMATOLOGY FOR 850MB TEMPS OF AROUND -6C AND CONSIDERING THAT CLOUDS SHOULD FILL IN BY AFTERNOON. SOME FLURRIES MAY LINGER THIS EVENING...BUT TOUGH TO PLACE WHERE THOSE COULD BE RIGHT NOW. ALSO CHALLENGING TO FORESEE THE EVOLUTION OF THE CLOUD FIELD TONIGHT...WITH SOME INEVITABLE STRATOCU HOLES AND MAYBE EVEN EVENTUALLY FULL CLEARING LATE. SO MINS COULD VARY QUITE A BIT...BUT EXPECTING WIDESPREAD 20S IN OUTLYING AREAS. THURSDAY AND FRIDAY...THE IMPRESSIVE...IN FACT NEAR RECORD COLD AIR AT 850MB FOR THIS TIME OF YEAR...WILL MOVE OVER THE REGION ON THURSDAY AND THURSDAY NIGHT. THE MINIMUM 850MB TEMPERATURE ON THE DVN/ILX UPPER AIR PERIODS OF RECORD ARE RIGHT AROUND THE FORECAST OF -10C. SO THIS SETS THE STAGE FOR POTENTIAL RECORD COLD ON THU NIGHT WHEN A CLEAR SKY IS PROBABLE AND LIKELY RAPID DECOUPLING IN THE EVENING SHOULD ALLOW FOR QUICK DIMINISHING OF WINDS. WITH THU HIGHS AGAIN ONLY IN THE LOWER...TO POSSIBLY MID 40S...THE LOW STARTING POINT GOING INTO THE NIGHT WILL ALSO HELP. HAVE THU NIGHT LOWS FORECAST IN THE LOWER TO MID 20S...WITH LIKELY SOME UPPER TEENS IF THE LOWER 20S ARE WIDESPREAD. DOWNTOWN CHICAGO MAY ALSO SEE THEIR FIRST FREEZE. FRIDAY WILL HAVE A SLOW MODERATION IN TEMPS AND THEN RETURN FLOW FRIDAY NIGHT...WHICH IS WELL AGREED UPON IN GUIDANCE...LOOKS TO WARM TEMPS OVERNIGHT INTO SATURDAY. THIS WEEKEND AND EARLY NEXT WEEK...GUIDANCE BEGINS TO QUICKLY SHOW SPREAD THROUGH THIS PERIOD...BUT FOR THE MOST IS IN STRONG AGREEMENT OF A COLD FRONT DROPPING THROUGH ON SATURDAY. IF EARLY ENOUGH THIS MAY BRING AN AFTERNOON DROP IN TEMPERATURES. NOT MUCH THERE FOR FORCING OR SATURATION IN CURRENT GUIDANCE TO SUPPORT ANY POPS WITH THIS. AS THE TRAIN OF SYSTEMS IN NW FLOW ACROSS CANADA CONTINUES...A STRONG COLD FRONT APPROACHES THE AREA BY MONDAY...BUT THIS GETS HUNG UP AS AN UPPER LOW DIGS IN THE WESTERN U.S. AND FORCES HEIGHT RISES OVER THE REGION. THIS FRONT IS WIDELY DISAGREED UPON ON GUIDANCE AND SHOULD SERVE AS A PRETTY GOOD FOCUS FOR PRECIP WHERE IT BEGINS TO LIFT NORTH AS A WARM FRONT. TEMPS MAY BE MUCH COOLER UNDER THIS PRECIP...BUT TO THE SOUTH AT OR MAYBE EVEN ABOVE NORMAL. MTF && .CLIMATE... RECORD LOW TEMPERATURES IN OUTLYING AREAS MAY BE APPROACHED OR SET FRIDAY MORNING IF CLOUDS DEPART AS FORECAST. FOR CHICAGO...THE CLIMATE PERIOD OF RECORD INCLUDES SOME COLDER YEARS IN THE 1880S...WITH THE RECORD LOW BEING IN THE TEENS WHICH WILL VERY LIKELY NOT BE APPROACHED AT OHARE. BUT FOR OUR OTHER LONG TERM CLIMATE SITE OF ROCKFORD WHICH DATES BACK TO 1905...IT IS VERY POSSIBLE. RECORD LOW FOR ROCKFORD ON OCTOBER 25TH: 23 (1987) MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * LOWER END VFR CIGS DEVELOPING THIS AFTERNOON. * SCT -SHSN POSSIBLE. LASTING IMPACT NOT LIKELY. KREIN //DISCUSSION...UPDATED 20Z... THE REGION WILL REMAIN UNDER WNWLY-NWLY FLOW AS HIGH PRESSURE STRETCHES FROM THE NRN PLAINS TO THE LOWER MS VLY AND DEEP LOW PRESSURE CONTINUE TO LIFT NE THROUGH NRN QUEBEC. DAYTIME MIXING UNDER MOSTLY SUNNY SKIES...AT LEAST INITIALLY...WILL BRING SOME HIGHER GUSTS DOWN TO THE SFC...IN THE 15-20KT RANGE. LATEST SATELLITE IMAGERY SHOWS A THINNING ST DECK BEING REPLACED BY A CU/STRATOCU DECK...AND CLOUD COVERAGE SHOULD INCREASE THROUGH THE AFTERNOON. RFD WILL HAVE THE BEST CHANCE TO SEE THE POTENTIAL FOR CIGS TO DROP IN THE HIGHER END MVFR RANGES...AT THIS POINT...EXPECT THAT CIGS OVER THE ERN TERMINALS SHOULD REMAIN VFR...THROUGH A BRIEF PERIOD OF MVFR CIGS IS NOT OUT OF THE QUESTION THROUGH THE AFTERNOON. WITH THE CLOUD CHARACTER BECOMING MORE CONVECTIVE THROUGH THE AFTERNOON...SCT -SHSN HAVE DEVELOPED. THE LOW LEVELS REMAIN FAIRLY DRY...SO DO NOT EXPECT ANY ACCUMULATING SNOW AND WITH FAST FLOW...ANY -SHSN IMPACTING THE TERMINALS WILL BRIEF. CLOUD COVERAGE WILL DISSIPATE WITH SUNSET...BUT A MODEST PRESSURE GRADIENT WILL KEEP WINDS IN THE 5-10KT RANGE OVERNIGHT. //ORD AND MDW CONFIDENCE...UPDATED 20Z... * MODERATE CONFIDENCE THAT DEVELOPING CIGS WILL REMAIN VFR...THOUGH THERE IS A CHANCE FOR CIGS TO DROP TO HIGHER END MVFR THIS AFTERNOON. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. * MODERATE TO HIGH CONFIDENCE THAT ANY PCPN OCCURRING AT THE TERMINALS WILL BE BRIEF AND HAVE MINIMAL IMPACT. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...CHANCE OF SHRA...MVFR POSSIBLE OVERNIGHT. TUESDAY...CHANCE OF SHRA...MVFR POSSIBLE. JEE && .MARINE... 210 PM CDT GALE POTENTIAL FRIDAY NIGHT AND SATURDAY MORNING IS THE MAIN CONCERN THIS FORECAST PERIOD. A STEADY PRESSURE GRADIENT REMAINS ACROSS THE WESTERN LAKES AS LOW PRESSURE DEEPENS OFF THE ATLANTIC COAST AND ONE AREA OF HIGH PRESSURE OVER WESTERN MISSOURI AND ARKANSAS DRIFTS SOUTHEASTWARD. A WEAK LOW IS MOVING ACROSS THE CENTRAL AND SOUTHERN PLAINS BEHIND THE HIGH BUT WILL BE FADING INTO THIS EVENING. ANOTHER HIGH IS MOVING SOUTHEAST FROM SOUTHERN ALBERTA AND SASKATCHEWAN WILL REACH THE LOWER OHIO VALLEY AND POINTS SOUTHEAST THURSDAY AND THURSDAY NIGHT. THE BAND OF CONVERGENT WINDS SEEN ALONG MUCH OF THE EASTERN SHORE OF THE LAKE ACROSS THE SOUTHERN HALF OF LOWER MICHIGAN WILL DIMINISH INTO THE EVENING ALLOWING A MORE UNIFORM NORTHWEST WIND AND WAVE DIRECTION TO SET UP THERE. THIS WILL LEAD TO BUILDING WAVES AS THE EASTERLY WIND COMPONENT DIMINISHES. OTHERWISE 15 TO 25 KT NORTHWEST WINDS WILL PERSIST THROUGH FRIDAY MORNING THOUGH THERE MAY BE FLUCTUATIONS BETWEEN THE LOWER AND UPPER PORTIONS OF THAT RANGE WHICH WILL BE DIFFICULT TO TIME AS SUBTLE WEAKNESSES IN THE PRESSURE GRADIENT MOVER ACROSS. THIS MAY LEAD TO SOMEWHAT LOWER WAVES AT TIMES. WILL KEEP THE SMALL CRAFT ADVISORY GOING FOR THE INDIANA NEARSHORE WATERS AS-IS FOR NOW AND WILL EVALUATE CANCELLING THE IL SIDE EARLIER BUT DETERMINE THAT JUST BEFORE ISSUANCE TIME THIS AFTERNOON. AS MENTIONED...FRIDAY AFTERNOON THROUGH SATURDAY IS THE MAIN PERIOD OF CONCERN. HIGH PRESSURE WILL BE MOVING SOUTHEAST ACROSS THE OHIO AND LOWER MISSISSIPPI RIVER VALLEYS WHILE AN ALBERTA CLIPPER DROPS SOUTHEASTWARD TOWARDS THE REGION. THE ASSOCIATED SURFACE LOW IS EXPECTED TO DEEPEN ACROSS NORTHERN LAKE SUPERIOR FRIDAY EVENING AS THE TRACK TURNS EASTERLY WITH THE LOW CENTER LOOKING TO REMAIN NORTH OF LAKE MICHIGAN. STRONG LOW AND MID LEVEL SOUTHWESTERLY WINDS WILL DEVELOP THROUGH THE DAY FRIDAY WITH UNSTABLE CONDITIONS REMAINING OVER THE LAKE THANKS TO THE STILL COLD AIRMASS. SOUTHWEST GALES LOOK TO DEVELOP FRIDAY EVENING AHEAD OF THE LOW WITH A PEAK INTENSITY LATE FRIDAY EVENING AND EARLY SATURDAY AS THE LOW PASSES BRINGING A COLD FRONT ACROSS THE LAKE. THIS WILL TURN WINDS WESTERLY BY SATURDAY MORNING AND NORTHWESTERLY THROUGH THE DAY. THIS TYPE OF SYSTEM IS CERTAINLY CAPABLE OF GALES BUT DO HAVE A FEW CONCERNS REGARDING POTENTIAL INTENSITY. GUIDANCE HAS HAD A HARD TIME WITH THESE SYSTEMS OF LATE BUT THIS ONE LOOKS TO BE ONE OF THE BETTER ORGANIZED AND TYPICAL TYPE CLIPPERS WE HAVE SEEN SO HAVE BETTER CONFIDENCE IN THEIR ABILITY TO PROVIDE REASONABLE OUTPUT. GIVEN THE STRENGTH OF THE LOW AND DEPARTING HIGH AHEAD OF IT LOW LEVEL WINDS COULD BECOME QUITE STRONG WITH MIXING DEPTH BEING KEY IN DETERMINING PEAK WINDS. TIMING MAY NEED TO BE ADJUSTED SOMEWHAT BUT RIGHT NOW FRIDAY EVENING AND FRIDAY NIGHT LOOK TO BE THE WORST PERIODS WITH SOME POSSIBILITY THAT 40-45 KT SOUTHWEST WINDS MAY OCCUR FOR AT LEAST A BRIEF PERIOD. THIS WILL HINGE ON THE EXACT TRACK AND INTENSITY OF THE LOW SO WILL STAY ON THE LOWER END OF GALES FOR NOW. SPEEDS WILL GRADUALLY EASE INTO SATURDAY NIGHT AS HIGH PRESSURE QUICKLY MOVES FROM THE NORTHERN ROCKIES TO SOUTHERN PLAINS. A RIDGE AXIS WILL BRIEFLY MOVE ACROSS THE LAKE BRINGING A LULL IN WINDS SOMETIME SUNDAY. FORECAST CONFIDENCE DROPS OFF EARLY NEXT WEEK AS THE UPPER FLOW PATTERN ATTEMPTS TO SHIFT. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM WEDNESDAY. && $$ 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
NWS CHICAGO/ROMEOVILLE IL
213 PM CDT WED OCT 23 2013 .DISCUSSION... 327 AM CDT AFTER LOOKING LIKE EARLY WINTER YESTERDAY IT WILL CONTINUE TO FEEL AS SUCH FOR A COUPLE DAYS...WITH THE FORECAST CHALLENGES TIED TO WELL BELOW NORMAL TEMPERATURES THESE NEXT FEW DAYS AND THEN SWINGING BACK TO CLOSER TO NORMAL THIS WEEKEND AND MAYBE MORE SO INTO EARLY NEXT WEEK. SYNOPSIS...THE PESKY CLIPPER SYSTEM FROM YESTERDAY IS RACING EASTWARD ACROSS THE UPPER OHIO VALLEY EARLY THIS MORNING. IN ITS WAKE 70M HEIGHT FALLS WERE OBSERVED AT 500MB LAST EVE AS THE LARGE SCALE LONG WAVE TROUGH ACROSS EASTERN/CENTRAL NORTH AMERICA CONTINUES TO BE RE-ESTABLISHED. THAT WILL REMAIN THE DOMINANT INFLUENCE ON THE LOCAL WEATHER PATTERN THIS WEEK...WITH PERSISTENT UPPER LEVEL NORTHWEST FLOW. A SERIES OF MID-LEVEL PERTURBATIONS WILL TRAVERSE IN THIS FLOW TODAY AND TONIGHT...AGAIN FURTHER LEADING TO LOWERED HEIGHTS AND COLD ADVECTION. WITH HIGH PRESSURE REMAINING ACROSS THE CENTRAL PLAINS ALLOWING FOR NO RETURN LOW-LEVEL FLOW...THIS ENABLES AN IDEAL REGIME FOR TEMPERATURES TO REMAIN COLD BY MID-AUTUMN STANDARDS. EARLY THIS MORNING...LOW-LEVEL CONVERGENCE OVER THE LAKE HAS BEEN NOTED IN OBSERVATIONS AND EARLIER WAS ANALYZED FROM MID-LAKE INTO PORTER COUNTY. BUT THIS HAS SHIFTED EAST AND MOST OF THE DEVELOPMENT IS MOVING SOUTHEAST FROM IT...SO ALL IN ALL MOST IF NOT ALL OF PORTER COUNTY LOOKS TO REMAIN FREE OF THE CONVECTIVE SHOWERS OVER THE LAKE THIS MORNING. TODAY AND TONIGHT...MULTIPLE COMPACT AND SHEARED SHORT WAVES ARE NOTED ON THE CYCLONIC SIDE OF THE STRONG UPPER JET FROM MANITOBA INTO THE CORN BELT. UPSTREAM RADAR IMAGERY AND OBSERVATIONS ACROSS MN HAVE INDICATED SOME SNOW SHOWERS WITH THESE. ADD TO THAT SOME MORNING SUNSHINE ACROSS PARTS OF OUR CWA...AND WE SHOULD QUICKLY DESTABILIZE IN THE IMMEDIATE LOW-LEVELS UNDER THESE FEATURES. NAM AND RAP FORECAST BUFR SOUNDINGS FOR OUR FORECAST NOON TEMPS BOTH YIELD ALMOST 100 J/KG OF CAPE. WET BULB ZEROS WERE ANALYZED ON LAST NIGHTS RAOBS AND FORECAST BY TODAYS SOUNDINGS TO BE ONLY AROUND 1000 FT AGL. SO WOULD EXPECT ANY ISOLATED DEVELOPMENT TO BE MAINLY SNOW SHOWERS/FLURRIES. ITS POSSIBLE A COUPLE OF THESE PRODUCE BRIEF MODERATE RATES...BUT WOULD BE VERY TEMPORARY LASTING. HIGHS TODAY SHOULD BE LOWER TO MID 40S BASED ON CLIMATOLOGY FOR 850MB TEMPS OF AROUND -6C AND CONSIDERING THAT CLOUDS SHOULD FILL IN BY AFTERNOON. SOME FLURRIES MAY LINGER THIS EVENING...BUT TOUGH TO PLACE WHERE THOSE COULD BE RIGHT NOW. ALSO CHALLENGING TO FORESEE THE EVOLUTION OF THE CLOUD FIELD TONIGHT...WITH SOME INEVITABLE STRATOCU HOLES AND MAYBE EVEN EVENTUALLY FULL CLEARING LATE. SO MINS COULD VARY QUITE A BIT...BUT EXPECTING WIDESPREAD 20S IN OUTLYING AREAS. THURSDAY AND FRIDAY...THE IMPRESSIVE...IN FACT NEAR RECORD COLD AIR AT 850MB FOR THIS TIME OF YEAR...WILL MOVE OVER THE REGION ON THURSDAY AND THURSDAY NIGHT. THE MINIMUM 850MB TEMPERATURE ON THE DVN/ILX UPPER AIR PERIODS OF RECORD ARE RIGHT AROUND THE FORECAST OF -10C. SO THIS SETS THE STAGE FOR POTENTIAL RECORD COLD ON THU NIGHT WHEN A CLEAR SKY IS PROBABLE AND LIKELY RAPID DECOUPLING IN THE EVENING SHOULD ALLOW FOR QUICK DIMINISHING OF WINDS. WITH THU HIGHS AGAIN ONLY IN THE LOWER...TO POSSIBLY MID 40S...THE LOW STARTING POINT GOING INTO THE NIGHT WILL ALSO HELP. HAVE THU NIGHT LOWS FORECAST IN THE LOWER TO MID 20S...WITH LIKELY SOME UPPER TEENS IF THE LOWER 20S ARE WIDESPREAD. DOWNTOWN CHICAGO MAY ALSO SEE THEIR FIRST FREEZE. FRIDAY WILL HAVE A SLOW MODERATION IN TEMPS AND THEN RETURN FLOW FRIDAY NIGHT...WHICH IS WELL AGREED UPON IN GUIDANCE...LOOKS TO WARM TEMPS OVERNIGHT INTO SATURDAY. THIS WEEKEND AND EARLY NEXT WEEK...GUIDANCE BEGINS TO QUICKLY SHOW SPREAD THROUGH THIS PERIOD...BUT FOR THE MOST IS IN STRONG AGREEMENT OF A COLD FRONT DROPPING THROUGH ON SATURDAY. IF EARLY ENOUGH THIS MAY BRING AN AFTERNOON DROP IN TEMPERATURES. NOT MUCH THERE FOR FORCING OR SATURATION IN CURRENT GUIDANCE TO SUPPORT ANY POPS WITH THIS. AS THE TRAIN OF SYSTEMS IN NW FLOW ACROSS CANADA CONTINUES...A STRONG COLD FRONT APPROACHES THE AREA BY MONDAY...BUT THIS GETS HUNG UP AS AN UPPER LOW DIGS IN THE WESTERN U.S. AND FORCES HEIGHT RISES OVER THE REGION. THIS FRONT IS WIDELY DISAGREED UPON ON GUIDANCE AND SHOULD SERVE AS A PRETTY GOOD FOCUS FOR PRECIP WHERE IT BEGINS TO LIFT NORTH AS A WARM FRONT. TEMPS MAY BE MUCH COOLER UNDER THIS PRECIP...BUT TO THE SOUTH AT OR MAYBE EVEN ABOVE NORMAL. MTF && .CLIMATE... RECORD LOW TEMPERATURES IN OUTLYING AREAS MAY BE APPROACHED OR SET FRIDAY MORNING IF CLOUDS DEPART AS FORECAST. FOR CHICAGO...THE CLIMATE PERIOD OF RECORD INCLUDES SOME COLDER YEARS IN THE 1880S...WITH THE RECORD LOW BEING IN THE TEENS WHICH WILL VERY LIKELY NOT BE APPROACHED AT OHARE. BUT FOR OUR OTHER LONG TERM CLIMATE SITE OF ROCKFORD WHICH DATES BACK TO 1905...IT IS VERY POSSIBLE. RECORD LOW FOR ROCKFORD ON OCTOBER 25TH: 23 (1987) MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * LOWER END VFR CIGS DEVELOPING THIS AFTERNOON. KREIN //DISCUSSION...UPDATED 18Z... THE REGION WILL REMAIN UNDER WNWLY-NWLY FLOW AS HIGH PRESSURE STRETCHES FROM THE NRN PLAINS TO THE LOWER MS VLY AND DEEP LOW PRESSURE CONTINUE TO LIFT NE THROUGH NRN QUEBEC. DAYTIME MIXING UNDER MOSTLY SUNNY SKIES...AT LEAST INITIALLY...WILL BRING SOME HIGHER GUSTS DOWN TO THE SFC...IN THE 15-20KT RANGE. LATEST SATELLITE IMAGERY SHOWS A THINNING ST DECK BEING REPLACED BY A CU/STRATOCU DECK...AND CLOUD COVERAGE SHOULD INCREASE THROUGH THE AFTERNOON. RFD WILL HAVE THE BEST CHANCE TO SEE THE POTENTIAL FOR CIGS TO DROP IN THE HIGHER END MVFR RANGES...AT THIS POINT...EXPECT THAT CIGS OVER THE ERN TERMINALS SHOULD REMAIN VFR...THROUGH A BRIEF PERIOD OF MVFR CIGS IS NOT OUT OF THE QUESTION THROUGH THE AFTERNOON. WITH THE CLOUD CHARACTER BECOME MORE CONVECTIVE THROUGH THE AFTERNOON...THE IS A CHANCE FOR A FEW ISOLD -SHSN...BUT GIVEN THE RATHER DRY AIRMASS IN THE LOWER LEVELS...THE CHANCES FOR ANYTHING MORE THAN VIRGA IS SLIM. CLOUD COVERAGE WILL DISSIPATE WITH SUNSET...BUT A MODEST PRESSURE GRADIENT WILL KEEP WINDS IN THE 5-10KT RANGE OVERNIGHT. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MODERATE CONFIDENCE THAT DEVELOPING CIGS WILL REMAIN VFR...THOUGH THERE IS A CHANCE FOR CIGS TO DROP TO HIGHER END MVFR THIS AFTERNOON. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...CHANCE OF SHRA...MVFR POSSIBLE OVERNIGHT. TUESDAY...CHANCE OF SHRA...MVFR POSSIBLE. JEE && .MARINE... 210 PM CDT GALE POTENTIAL FRIDAY NIGHT AND SATURDAY MORNING IS THE MAIN CONCERN THIS FORECAST PERIOD. A STEADY PRESSURE GRADIENT REMAINS ACROSS THE WESTERN LAKES AS LOW PRESSURE DEEPENS OFF THE ATLANTIC COAST AND ONE AREA OF HIGH PRESSURE OVER WESTERN MISSOURI AND ARKANSAS DRIFTS SOUTHEASTWARD. A WEAK LOW IS MOVING ACROSS THE CENTRAL AND SOUTHERN PLAINS BEHIND THE HIGH BUT WILL BE FADING INTO THIS EVENING. ANOTHER HIGH IS MOVING SOUTHEAST FROM SOUTHERN ALBERTA AND SASKATCHEWAN WILL REACH THE LOWER OHIO VALLEY AND POINTS SOUTHEAST THURSDAY AND THURSDAY NIGHT. THE BAND OF CONVERGENT WINDS SEEN ALONG MUCH OF THE EASTERN SHORE OF THE LAKE ACROSS THE SOUTHERN HALF OF LOWER MICHIGAN WILL DIMINISH INTO THE EVENING ALLOWING A MORE UNIFORM NORTHWEST WIND AND WAVE DIRECTION TO SET UP THERE. THIS WILL LEAD TO BUILDING WAVES AS THE EASTERLY WIND COMPONENT DIMINISHES. OTHERWISE 15 TO 25 KT NORTHWEST WINDS WILL PERSIST THROUGH FRIDAY MORNING THOUGH THERE MAY BE FLUCTUATIONS BETWEEN THE LOWER AND UPPER PORTIONS OF THAT RANGE WHICH WILL BE DIFFICULT TO TIME AS SUBTLE WEAKNESSES IN THE PRESSURE GRADIENT MOVER ACROSS. THIS MAY LEAD TO SOMEWHAT LOWER WAVES AT TIMES. WILL KEEP THE SMALL CRAFT ADVISORY GOING FOR THE INDIANA NEARSHORE WATERS AS-IS FOR NOW AND WILL EVALUATE CANCELLING THE IL SIDE EARLIER BUT DETERMINE THAT JUST BEFORE ISSUANCE TIME THIS AFTERNOON. AS MENTIONED...FRIDAY AFTERNOON THROUGH SATURDAY IS THE MAIN PERIOD OF CONCERN. HIGH PRESSURE WILL BE MOVING SOUTHEAST ACROSS THE OHIO AND LOWER MISSISSIPPI RIVER VALLEYS WHILE AN ALBERTA CLIPPER DROPS SOUTHEASTWARD TOWARDS THE REGION. THE ASSOCIATED SURFACE LOW IS EXPECTED TO DEEPEN ACROSS NORTHERN LAKE SUPERIOR FRIDAY EVENING AS THE TRACK TURNS EASTERLY WITH THE LOW CENTER LOOKING TO REMAIN NORTH OF LAKE MICHIGAN. STRONG LOW AND MID LEVEL SOUTHWESTERLY WINDS WILL DEVELOP THROUGH THE DAY FRIDAY WITH UNSTABLE CONDITIONS REMAINING OVER THE LAKE THANKS TO THE STILL COLD AIRMASS. SOUTHWEST GALES LOOK TO DEVELOP FRIDAY EVENING AHEAD OF THE LOW WITH A PEAK INTENSITY LATE FRIDAY EVENING AND EARLY SATURDAY AS THE LOW PASSES BRINGING A COLD FRONT ACROSS THE LAKE. THIS WILL TURN WINDS WESTERLY BY SATURDAY MORNING AND NORTHWESTERLY THROUGH THE DAY. THIS TYPE OF SYSTEM IS CERTAINLY CAPABLE OF GALES BUT DO HAVE A FEW CONCERNS REGARDING POTENTIAL INTENSITY. GUIDANCE HAS HAD A HARD TIME WITH THESE SYSTEMS OF LATE BUT THIS ONE LOOKS TO BE ONE OF THE BETTER ORGANIZED AND TYPICAL TYPE CLIPPERS WE HAVE SEEN SO HAVE BETTER CONFIDENCE IN THEIR ABILITY TO PROVIDE REASONABLE OUTPUT. GIVEN THE STRENGTH OF THE LOW AND DEPARTING HIGH AHEAD OF IT LOW LEVEL WINDS COULD BECOME QUITE STRONG WITH MIXING DEPTH BEING KEY IN DETERMINING PEAK WINDS. TIMING MAY NEED TO BE ADJUSTED SOMEWHAT BUT RIGHT NOW FRIDAY EVENING AND FRIDAY NIGHT LOOK TO BE THE WORST PERIODS WITH SOME POSSIBILITY THAT 40-45 KT SOUTHWEST WINDS MAY OCCUR FOR AT LEAST A BRIEF PERIOD. THIS WILL HINGE ON THE EXACT TRACK AND INTENSITY OF THE LOW SO WILL STAY ON THE LOWER END OF GALES FOR NOW. SPEEDS WILL GRADUALLY EASE INTO SATURDAY NIGHT AS HIGH PRESSURE QUICKLY MOVES FROM THE NORTHERN ROCKIES TO SOUTHERN PLAINS. A RIDGE AXIS WILL BRIEFLY MOVE ACROSS THE LAKE BRINGING A LULL IN WINDS SOMETIME SUNDAY. FORECAST CONFIDENCE DROPS OFF EARLY NEXT WEEK AS THE UPPER FLOW PATTERN ATTEMPTS TO SHIFT. MDB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM WEDNESDAY. && $$ 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
NWS CHICAGO/ROMEOVILLE IL
1236 PM CDT WED OCT 23 2013 .DISCUSSION... 327 AM CDT AFTER LOOKING LIKE EARLY WINTER YESTERDAY IT WILL CONTINUE TO FEEL AS SUCH FOR A COUPLE DAYS...WITH THE FORECAST CHALLENGES TIED TO WELL BELOW NORMAL TEMPERATURES THESE NEXT FEW DAYS AND THEN SWINGING BACK TO CLOSER TO NORMAL THIS WEEKEND AND MAYBE MORE SO INTO EARLY NEXT WEEK. SYNOPSIS...THE PESKY CLIPPER SYSTEM FROM YESTERDAY IS RACING EASTWARD ACROSS THE UPPER OHIO VALLEY EARLY THIS MORNING. IN ITS WAKE 70M HEIGHT FALLS WERE OBSERVED AT 500MB LAST EVE AS THE LARGE SCALE LONG WAVE TROUGH ACROSS EASTERN/CENTRAL NORTH AMERICA CONTINUES TO BE RE-ESTABLISHED. THAT WILL REMAIN THE DOMINANT INFLUENCE ON THE LOCAL WEATHER PATTERN THIS WEEK...WITH PERSISTENT UPPER LEVEL NORTHWEST FLOW. A SERIES OF MID-LEVEL PERTURBATIONS WILL TRAVERSE IN THIS FLOW TODAY AND TONIGHT...AGAIN FURTHER LEADING TO LOWERED HEIGHTS AND COLD ADVECTION. WITH HIGH PRESSURE REMAINING ACROSS THE CENTRAL PLAINS ALLOWING FOR NO RETURN LOW-LEVEL FLOW...THIS ENABLES AN IDEAL REGIME FOR TEMPERATURES TO REMAIN COLD BY MID-AUTUMN STANDARDS. EARLY THIS MORNING...LOW-LEVEL CONVERGENCE OVER THE LAKE HAS BEEN NOTED IN OBSERVATIONS AND EARLIER WAS ANALYZED FROM MID-LAKE INTO PORTER COUNTY. BUT THIS HAS SHIFTED EAST AND MOST OF THE DEVELOPMENT IS MOVING SOUTHEAST FROM IT...SO ALL IN ALL MOST IF NOT ALL OF PORTER COUNTY LOOKS TO REMAIN FREE OF THE CONVECTIVE SHOWERS OVER THE LAKE THIS MORNING. TODAY AND TONIGHT...MULTIPLE COMPACT AND SHEARED SHORT WAVES ARE NOTED ON THE CYCLONIC SIDE OF THE STRONG UPPER JET FROM MANITOBA INTO THE CORN BELT. UPSTREAM RADAR IMAGERY AND OBSERVATIONS ACROSS MN HAVE INDICATED SOME SNOW SHOWERS WITH THESE. ADD TO THAT SOME MORNING SUNSHINE ACROSS PARTS OF OUR CWA...AND WE SHOULD QUICKLY DESTABILIZE IN THE IMMEDIATE LOW-LEVELS UNDER THESE FEATURES. NAM AND RAP FORECAST BUFR SOUNDINGS FOR OUR FORECAST NOON TEMPS BOTH YIELD ALMOST 100 J/KG OF CAPE. WET BULB ZEROS WERE ANALYZED ON LAST NIGHTS RAOBS AND FORECAST BY TODAYS SOUNDINGS TO BE ONLY AROUND 1000 FT AGL. SO WOULD EXPECT ANY ISOLATED DEVELOPMENT TO BE MAINLY SNOW SHOWERS/FLURRIES. ITS POSSIBLE A COUPLE OF THESE PRODUCE BRIEF MODERATE RATES...BUT WOULD BE VERY TEMPORARY LASTING. HIGHS TODAY SHOULD BE LOWER TO MID 40S BASED ON CLIMATOLOGY FOR 850MB TEMPS OF AROUND -6C AND CONSIDERING THAT CLOUDS SHOULD FILL IN BY AFTERNOON. SOME FLURRIES MAY LINGER THIS EVENING...BUT TOUGH TO PLACE WHERE THOSE COULD BE RIGHT NOW. ALSO CHALLENGING TO FORESEE THE EVOLUTION OF THE CLOUD FIELD TONIGHT...WITH SOME INEVITABLE STRATOCU HOLES AND MAYBE EVEN EVENTUALLY FULL CLEARING LATE. SO MINS COULD VARY QUITE A BIT...BUT EXPECTING WIDESPREAD 20S IN OUTLYING AREAS. THURSDAY AND FRIDAY...THE IMPRESSIVE...IN FACT NEAR RECORD COLD AIR AT 850MB FOR THIS TIME OF YEAR...WILL MOVE OVER THE REGION ON THURSDAY AND THURSDAY NIGHT. THE MINIMUM 850MB TEMPERATURE ON THE DVN/ILX UPPER AIR PERIODS OF RECORD ARE RIGHT AROUND THE FORECAST OF -10C. SO THIS SETS THE STAGE FOR POTENTIAL RECORD COLD ON THU NIGHT WHEN A CLEAR SKY IS PROBABLE AND LIKELY RAPID DECOUPLING IN THE EVENING SHOULD ALLOW FOR QUICK DIMINISHING OF WINDS. WITH THU HIGHS AGAIN ONLY IN THE LOWER...TO POSSIBLY MID 40S...THE LOW STARTING POINT GOING INTO THE NIGHT WILL ALSO HELP. HAVE THU NIGHT LOWS FORECAST IN THE LOWER TO MID 20S...WITH LIKELY SOME UPPER TEENS IF THE LOWER 20S ARE WIDESPREAD. DOWNTOWN CHICAGO MAY ALSO SEE THEIR FIRST FREEZE. FRIDAY WILL HAVE A SLOW MODERATION IN TEMPS AND THEN RETURN FLOW FRIDAY NIGHT...WHICH IS WELL AGREED UPON IN GUIDANCE...LOOKS TO WARM TEMPS OVERNIGHT INTO SATURDAY. THIS WEEKEND AND EARLY NEXT WEEK...GUIDANCE BEGINS TO QUICKLY SHOW SPREAD THROUGH THIS PERIOD...BUT FOR THE MOST IS IN STRONG AGREEMENT OF A COLD FRONT DROPPING THROUGH ON SATURDAY. IF EARLY ENOUGH THIS MAY BRING AN AFTERNOON DROP IN TEMPERATURES. NOT MUCH THERE FOR FORCING OR SATURATION IN CURRENT GUIDANCE TO SUPPORT ANY POPS WITH THIS. AS THE TRAIN OF SYSTEMS IN NW FLOW ACROSS CANADA CONTINUES...A STRONG COLD FRONT APPROACHES THE AREA BY MONDAY...BUT THIS GETS HUNG UP AS AN UPPER LOW DIGS IN THE WESTERN U.S. AND FORCES HEIGHT RISES OVER THE REGION. THIS FRONT IS WIDELY DISAGREED UPON ON GUIDANCE AND SHOULD SERVE AS A PRETTY GOOD FOCUS FOR PRECIP WHERE IT BEGINS TO LIFT NORTH AS A WARM FRONT. TEMPS MAY BE MUCH COOLER UNDER THIS PRECIP...BUT TO THE SOUTH AT OR MAYBE EVEN ABOVE NORMAL. MTF && .CLIMATE... RECORD LOW TEMPERATURES IN OUTLYING AREAS MAY BE APPROACHED OR SET FRIDAY MORNING IF CLOUDS DEPART AS FORECAST. FOR CHICAGO...THE CLIMATE PERIOD OF RECORD INCLUDES SOME COLDER YEARS IN THE 1880S...WITH THE RECORD LOW BEING IN THE TEENS WHICH WILL VERY LIKELY NOT BE APPROACHED AT OHARE. BUT FOR OUR OTHER LONG TERM CLIMATE SITE OF ROCKFORD WHICH DATES BACK TO 1905...IT IS VERY POSSIBLE. RECORD LOW FOR ROCKFORD ON OCTOBER 25TH: 23 (1987) MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * LOWER END VFR CIGS DEVELOPING THIS AFTERNOON. KREIN //DISCUSSION...UPDATED 18Z... THE REGION WILL REMAIN UNDER WNWLY-NWLY FLOW AS HIGH PRESSURE STRETCHES FROM THE NRN PLAINS TO THE LOWER MS VLY AND DEEP LOW PRESSURE CONTINUE TO LIFT NE THROUGH NRN QUEBEC. DAYTIME MIXING UNDER MOSTLY SUNNY SKIES...AT LEAST INITIALLY...WILL BRING SOME HIGHER GUSTS DOWN TO THE SFC...IN THE 15-20KT RANGE. LATEST SATELLITE IMAGERY SHOWS A THINNING ST DECK BEING REPLACED BY A CU/STRATOCU DECK...AND CLOUD COVERAGE SHOULD INCREASE THROUGH THE AFTERNOON. RFD WILL HAVE THE BEST CHANCE TO SEE THE POTENTIAL FOR CIGS TO DROP IN THE HIGHER END MVFR RANGES...AT THIS POINT...EXPECT THAT CIGS OVER THE ERN TERMINALS SHOULD REMAIN VFR...THROUGH A BRIEF PERIOD OF MVFR CIGS IS NOT OUT OF THE QUESTION THROUGH THE AFTERNOON. WITH THE CLOUD CHARACTER BECOME MORE CONVECTIVE THROUGH THE AFTERNOON...THE IS A CHANCE FOR A FEW ISOLD -SHSN...BUT GIVEN THE RATHER DRY AIRMASS IN THE LOWER LEVELS...THE CHANCES FOR ANYTHING MORE THAN VIRGA IS SLIM. CLOUD COVERAGE WILL DISSIPATE WITH SUNSET...BUT A MODEST PRESSURE GRADIENT WILL KEEP WINDS IN THE 5-10KT RANGE OVERNIGHT. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * MODERATE CONFIDENCE THAT DEVELOPING CIGS WILL REMAIN VFR...THOUGH THERE IS A CHANCE FOR CIGS TO DROP TO HIGHER END MVFR THIS AFTERNOON. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. KREIN //OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z... THURSDAY NIGHT THROUGH SUNDAY...VFR. MONDAY...CHANCE OF SHRA...MVFR POSSIBLE OVERNIGHT. TUESDAY...CHANCE OF SHRA...MVFR POSSIBLE. JEE && .MARINE... 315 AM CDT LOW PRESSURE IS OVER SE INDIANA WHILE A WEAK HIGH PRESSURE SINKS SOUTH OVER THE GULF COAST THIS EVENING. A SECOND WEAKER LOW OVER THE NORTHERN ROCKIES WILL ALSO TRAVEL DOWN THE PLAINS DISSIPATING OVER TEXAS THIS EVENING. A MUCH LARGER HIGH WILL BUILD OVER THE PLAINS TONIGHT THROUGH THURSDAY WITH NORTHWEST WINDS 15-25 KT EXPECTED ACROSS THE LAKE. THERE IS A CHANCE OF WATERSPOUTS ACROSS THE EASTERN SIDE OF THE LAKE AGAIN TODAY. HAZARDOUS WAVES ARE STILL EXPECTED ACROSS THE NEARSHORE WATERS TODAY AND WAVES WILL DIMINISH FOR A FEW HOURS LATE THIS EVENING ACROSS THE IL SIDE OF THE LAKE. HAZARDOUS WAVES WILL BUILD BACK EARLY THURSDAY MORNING SO ANOTHER SMALL CRAFT ADVISORY WILL BE NEEDED OVER THE IL NEARSHORE WATERS. WAVES FINALLY SUBSIDE TO BELOW SMALL CRAFT CRITERIA FRIDAY AFTERNOON. THE HIGH WILL SPREAD ACROSS THE SE US FRIDAY AND OVER THE WEEKEND WHILE A STRONG LOW PASSES OVER THE NORTHERN GREAT LAKES FRIDAY NIGHT AND SATURDAY. THE GRADIENT OVER THE LAKE WILL TIGHTEN DRAMATICALLY THEREFORE PUT LOW END GALES INTO THE FORECAST FOR FRIDAY NIGHT ACROSS THE LAKE. WINDS TURN NORTHWEST BEHIND THE LOWS COLD FRONT AND A BRIEF PERIOD OF NORTHWEST GALES IS ALSO POSSIBLE SATURDAY EVENING. GUIDANCE THEN BEGINS TO DIFFER SIGNIFICANTLY WITH WHAT THE NEXT HIGH AND LOW PAIR WILL DO. IN GENERAL LOOKING AT LIGHT WEST TO SOUTHWEST WINDS SUNDAY WITH A BACKDOOR COLD FRONT POSSIBLE LATE SUNDAY NIGHT INTO MONDAY. THEN EAST WINDS ARE EXPECTED EARLY NEXT WEEK. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 3 PM FRIDAY. SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 10 PM WEDNESDAY. && $$ 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
NWS NORTHERN INDIANA
128 PM EDT WED OCT 23 2013 .SYNOPSIS... ISSUED AT 417 AM EDT WED OCT 23 2013 A SERIES OF DISTURBANCES WILL MOVE THROUGH THE REGION OVER THE NEXT COUPLE OF DAYS. LAKE EFFECT RAIN SHOWERS CAN BE EXPECTED ACROSS PORTIONS OF NORTHWESTERN INDIANA AND SOUTHWESTERN LOWER MICHIGAN OVER THE NEXT COUPLE OF DAYS AS THE COLD NORTHWESTERLY FLOW CONTINUES OVER THE WARM WATERS OF LAKE MICHIGAN. SNOW MAY BE MIXED AT TIMES WITH THE SHOWERS. AFTERNOON HIGH TEMPERATURES WILL CLIMB INTO THE LOWER TO MIDDLE 40S. OVERNIGHT LOWS WILL DROP BACK INTO THE LOWER 30S...EXCEPT MID 30S ALONG THE LAKESHORE. && .UPDATE... ISSUED AT 114 PM EDT WED OCT 23 2013 DOMINANT LAKE EFFECT BAND HAS MOVED INLAND THIS AFTN AND DISPERSING INTO MULTIPLE CELLS/BANS AS IT SLIDES ESE ACROSS OUR CWA AND WEAKENS. LAKE EFFECT SHOWERS EXPECTED TO REDEVELOP LATE THIS AFTN AND THIS EVE AS NW FLOW BECOMES REESTABLISHED OVER THE LAKE. EARLY AFTN UPDATE MAINLY TO FRESHEN WORDING... HWVR GIVEN LOW FREEZING LEVELS EXTENDED MENTION OF A RN/SN MIX IN SHOWERS THROUGH THE AFTN OVER MUCH OF THE AREA. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 417 AM EDT WED OCT 23 2013 COMPACT UPPER LOW HAS BEEN STEADY PROGRESS ESE DURING THE EVENING/OVERNIGHT HOURS...WITH CENTER SOMEWHERE AROUND INDIANAPOLIS. WHILE RAIN HAS BEEN THE DOMINANT PTYPE...SOME REPORTS OF SNOW OR SLEET OCCURRING HAVE BEEN RECEIVED IN OUR FAR SOUTHERN COUNTIES WITH SOME SLUSHY LIGHT ACCUMULATIONS NOTED IN SOME AREAS. THIS AREA WILL CONTINUE TO PULL AWAY BY 12Z WEDS. FURTHER NORTH...FLOW IS BECOMING MORE N AND NW AND ALLOWING FOR EXPANDING DEVELOPMENT OF LAKE EFFECT SHOWERS ACROSS MUCH OF LAKE MI. THE GREATEST CONCENTRATION HAS BEEN RESIDING ALONG THE EASTERN HALF AND SOMEWHAT INLAND INTO WESTERN LWR MI. LAKE INDUCED INSTABILITY REMAINS IN THE MODERATE TO EXTREME CATEGORY (SFC-850 MB/SFC-700 MB DELTA T VALUES OF LOW 20S AND LOW 30S RESPECTIVELY) WITH LAKE BASED CAPES APPROACHING 1000 J/KG. AN OCCASIONAL REPORT OF SLEET/GRAUPEL HAVE COME IN ASSOCIATED WITH THE STRONGER SHOWERS. AS THIS SHOULD CONTINUE...HAVE ADDED MENTION OF SLEET IN CATEGORICAL AREAS. IN TERMS OF TIMING AND COVERAGE HRRR HAS A NICE HANDLE ON BOTH PRECIP TO THE SOUTH AND EVOLUTION OF LAKE EFFECT SHOWERS. EXPECTING A CHAOTIC PATTERN TO THE LAKE EFFECT SHOWERS INITIALLY AS SFC OBS INDICATING MESO LOW THAT WAS ADVERTISED ON HIGH RES MODELS PAST COUPLE OF DAYS HAS TAKEN SHAPE OVER THE SOUTHERN PART OF THE LAKE. THIS FEATURE WILL WORK SLOWLY SOUTH AND MOVE ONSHORE IN THE 9 TO 12Z WINDOW. HAVE EXPANDED CAT POPS FURTHER EAST INTO ALL OF BERRIEN AS WELL AS PART OF CASS AND ST JOE INDIANA COUNTIES TO COVER UPSTREAM TRENDS. CHANCES FOR SNOW/GRAUPEL WILL DECREASE AFTER 15Z AS TEMPS BEGIN TO WARM INTO THE 40S. FOR THIS AFTERNOON...HI RES MODELS SEEM TO LOWER OVERALL DEPTH OF MSTR BUT STILL LINGER A DECENT AMOUNT WHERE STRONGEST OMEGA RESIDES. IN ADDITION...INSTABILITY WILL REMAIN UNCHANGED. WHILE SOME CONCERN THAT COVERAGE COULD DIMINISH SOMEWHAT IN THE 19 TO 23Z RANGE WITH THIS DECREASE IN MSTR...WILL GO WITH INSTABILITY MAKING UP THE DIFFERENCE WITH HIGH LIKELY/LOW CAT POPS WARRANTED (AND EXPANDED SLIGHTLY TO BETTER REFLECT EXPECTED FLOW). NEXT WAVE OF INTEREST...PRESENTLY DIVING SE THROUGH THE DAKOTAS...WILL APPROACH LATER THIS AFTERNOON AND TONIGHT. TRACK OF THIS FEATURE WILL AGAIN BE TO THE SW OF THE AREA... TRACKING THROUGH WESTERN IOWA INTO SOUTHERN ILLINOIS. CLOUD COVER WILL INCREASE NORTHEAST OF THE FEATURE ACROSS THE AREA BUT PRECIP CHANCES LOOK TO BE CONFINED DOWNWIND OF LK MI AS NW FLOW WILL INCREASE...AND BOUNDARY LAYER MOISTURE WILL PICK UP ONCE AGAIN. INCREASED POPS SOMEWHAT TO HIGH END LIKELY FOR NOW BUT SUBSEQUENT INCREASE TO CAT POPS MAY BE NEEDED IN LATER FORECASTS. LOWS WILL DROP INTO THE LOW 30S IN MOST SPOTS AWAY FROM THE LAKE WHICH MAY RESULT IN AN GREATER CHANCE OF SNOW VS RAIN BUT GIVEN LAKE PROCESSES PRECIP MAY REMAIN MAINLY RAIN. WILL KEEP MIX MENTION FOR NOW. && .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 417 AM EDT WED OCT 23 2013 LARGE SCALE TROUGH EXPECTED TO REMAIN OVER THE GREAT LAKES THROUGH THE WEEKEND BEFORE PATTERN BEGINS TO RELOAD WITH RISING HEIGHTS AND MODERATING TEMPERATURES NEXT WEEK. LAKE EFFECT RAIN AND SNOW SHOWERS WILL BE PRIMARY CONCERN DURING THE BEGINNING OF THE LONG TERM PERIOD. WEAK SHORT WAVE AND SURFACE TROUGH TO PASS ACROSS THE AREA EARLY THU MORNING. THIS WILL HELP INCREASE SFC-700 DELTA T VALUES TO OVER 30 PROVIDING EXTREME INSTABILITY FROM LAKE MICHIGAN. LAKE INDUCED CAPE VALUES RISE TO OVER 800 J/KG WITH NEARLY UNIDIRECTIONAL NW FETCH. 1000-850MB RH REMAINS ABOVE 80 PERCENT SO SEE LITTLE REASON THAT LAKE EFFECT SHOWERS WILL NOT BE ONGOING. HAVE RAISED POPS TO CATEGORICAL ACROSS MI COUNTIES NEAR THE LAKE AND TAPERED FURTHER INLAND. PCPN TYPE WILL BE QUITE DIFFICULT AROUND THE LAKE AS MODIFIED BOUNDARY LAYER SHOULD KEEP PCPN MAINLY RAIN NEAR THE LAKE WITH A MIX OF RAIN AND SNOW INLAND WHERE THERMAL PROFILES MORE FAVORABLE FOR SNOW. HEAVIER SHOWERS TO BRING PERIODS OF MAINLY SNOW AND SLEET BUT FOR NOW HAVE KEPT FORECAST AS A RAIN/SNOW MIX GIVEN DIFFICULTY OF NAILING DOWN THESE MESOSCALE DETAILS AT THIS TIME RANGE. SOME MINOR SNOW ACCUMULATIONS ON GRASSY SURFACES WILL BE POSSIBLE AWAY FROM THE LAKE...ESPECIALLY THU NIGHT WITH DIURNAL COOLING AND CONTINUED EXTREME INSTABILITY AND FAVORABLE TRAJECTORIES. GIVEN THE INSTABILITY EXPECT SOME RATHER IMPRESSIVE RAINFALL TOTALS WHERE BANDS ARE PERSISTENT. LAKE EFFECT TO BEGIN WINDING DOWN LATER FRIDAY MORNING AS FLOW BACKS AHEAD OF NEXT APPROACHING SHORT WAVE AND INVERSION HEIGHTS LOWER WITH DECREASING MOISTURE. DELTA T VALUES REMAIN FAVORABLE FOR SOME LIGHTER SHOWERS CLOSER TO LAKE AND EVEN FRIDAY NIGHT WITH SOUTHWEST FLOW AFFECTING FAR NORTHERN BERRIEN COUNTY. ATMOSPHERE BECOMING RATHER DRY BY THIS TIME SO OPTED FOR JUST A SLIGHT CHANCE POP WITH SFC-850MB DELTA T VALUES STILL AROUND 20. A BRIEF MODERATION IN TEMPS EXPECTED SAT AHEAD OF NEXT SHORT WAVE AND COLD FRONT. TEMPS WILL STRONGLY DEPEND ON HOW FAST CLOUDS MOVE IN SATURDAY. SOUTHERN AREAS SHOULD SEE LOW TO MID 50S WHILE NORTHERN AREAS CLIMB TO NEAR 50. THIS CLIPPER WILL BRING ANOTHER BRIEF SHOT OF COLDER AIR AND A CHANCE FOR ADDITIONAL LAKE EFFECT RAIN SHOWERS. MEDIUM RANGE MODELS IN GOOD AGREEMENT ON LARGE SCALE PATTERN FOR EARLY NEXT WEEK AS WEST COAST ENERGY BEGINS TO CARVE OUT A NEW TROUGH OVER THE WESTERN CONUS. THIS ALLOWS HEIGHTS TO RISE OVER THE MIDWEST WITH MODERATING TEMPERATURES MONDAY AND TUESDAY. A COLD FRONT WILL SAG SOUTH AND BECOME NEARLY STATIONARY EITHER ACROSS OR JUST NORTH OF OUR AREA AS IT BECOMES PARALLEL TO MID LEVEL FLOW. THIS FRONT WILL BE FOCUS FOR SHOWERS MONDAY INTO TUESDAY AND EVEN WEDNESDAY OF NEXT WEEK. A LOT TO WATCH WITH THIS EVOLUTION AS WARM SECTOR WILL LIKELY BE RELATIVELY WARM FOR OCTOBER AND A NICE BAROCLINIC ZONE WILL SET NEAR OUR AREA. SURFACE WAVE DEVELOPMENT AROUND DAY 7 WILL HELP BACK WINDS AND STRONG 100 KNOT JET LOOKS TO RACE TOWARD THE AREA. KINEMATICS LOOK FAVORABLE FOR SEVERE WEATHER IN THE MIDWEST OR MID SOUTH BUT INSTABILITY REMAINS A BIG UNKNOWN. HOWEVER...CLIMATOLOGY FAVORS A SECONDARY SEVERE WEATHER PEAK IN OCTOBER FOR WEAK INSTABILITY/HIGH SHEAR SEVERE WEATHER EVENTS. CERTAINLY WORTH WATCHING NEXT SEVERAL DAYS IN MODEL EVOLUTION. PATTERN REMAINS QUITE ACTIVE GIVEN NUMEROUS PACIFIC/ASIAN CYCLONES OVER THE LAST FEW WEEKS WHICH HAVE HELPED AMPLIFY THE MID LEVEL FLOW AND DOWNSTREAM PATTERN OVER THE CONUS. LONGER RANGE OUTLOOK FOR DAY 7-10 ALSO LOOKS QUITE INTERESTING WITH WEST CONUS LOW EJECTION TOWARD THE AREA BY LATE NEXT WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 114 PM EDT WED OCT 23 2013 DOMINANT LAKE EFFECT BAND HAS MOVED EAST OF SBN EARLY THIS AFTN AND BECOMING MORE CELLULAR AS IT MOVES ACROSS NRN INDIANA. THESE SHOWERS SHOULD IMPACT FWA OVER THE NEXT FEW HRS LOWERING CIGS AT TIMES TO NEAR IFR. LAKE EFFECT SHOWERS EXPECTED TO REDEVELOP LATE THIS AFTN/EVE AND LIKELY IMPACT SBN FOR THE REMAINDER OF THE PERIOD. FOR NOW KEPT CONDITIONS IN LOW VFR RANGE THROUGH THAT TIMEFRAME BUT SOME LOWER CONDITIONS PSBL IN HEAVIER SHOWERS. LOW VFR STRATO CU CIGS SHOULD CONT AT FWA TONIGHT AND THU. THERE IS A LOW CHC OF SHRA THERE ALSO BUT POPS TOO LOW TO INCLUDE IN FWA TAF ATTM. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT FRIDAY FOR LMZ043-046. && $$ UPDATE...JT SYNOPSIS...FISHER SHORT TERM...FISHER LONG TERM...LASHLEY AVIATION...JT VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1145 AM MDT WED OCT 23 2013 .SHORT TERM...(TODAY THROUGH FRIDAY NIGHT) ISSUED AT 305 AM MDT WED OCT 23 2013 LATEST WV IMAGERY AND RAP H5 ANALYSIS SHOWS NW FLOW STILL IN PLACE ACROSS PLAINS WITH LARGE SCALE TROUGH ACROSS THE EASTERN CONUS. MAIN STORM TRACK IS STILL OVER NORTHER PLAINS AND UPPER MISSISSIPPI VALLEY...WELL OUTSIDE OF OUR AREA OF CONCERN. AT THE SURFACE A BACKDOOR COLD FRONT HAS STALLED OVER OUR CWA...TO BE NEAR KGLD. NORTHEAST OF THIS FEATURE 10-12KFT CLOUD DECK ASSOCIATED WITH EMBEDDED ENERGY WITHIN MEAN UPPER FLOW IS MOVING ACROSS THE NORTHEASTERN PART OF OUR CWA. NW FLOW WILL SHIFT EAST WITH CONFLUENT PATTERN/LARGE SCALE SUBSIDENCE REMAINING IN PLACE THROUGH FRIDAY. QUASI-STATIONARY FRONT OVER THE CWA WILL SHIFT NORTHEAST TODAY AND THEN BACK TO THE WEST OF THE CWA TONIGHT...BEFORE LIFTING TO THE NORTH AGAIN BY FRIDAY. BREEZY CONDITIONS ARE ANTICIPATED DURING THE DAYTIME PERIODS TIED TO PEAK HEATING/MIXING. SURFACE HIGH PRESSURE BEGINS TO BUILD SOUTH TONIGHT BEHIND THIS FRONT WITH LIGHT EASTERLY FLOW AND INCREASING BL MOISTURE SUPPORTING POSSIBLE STRATUS/FOG. MODELS NEVER COMPLETELY SATURATE BOUNDARY LAYER...HOWEVER CONSIDERING THE PATTERN/CONCEPTUAL MODEL SUPPORTING FOG AND MET GUIDANCE SHOWING REDUCED VISIBILITIES I DECIDED TO ADD PATCHY FOG MENTION LATE FRIDAY NIGHT THROUGH THURSDAY MORNING. HIGHS WILL GENERALLY BE SEASONAL TODAY AND FRIDAY (HIGHS 60S TO NEAR 70F) WITH COOLER TEMPS THURSDAY AS A RESULT OF THE FRONT FURTHER WEST...WHEN AIR MASS OVER CWA WILL MAINLY SUPPORT HIGHS ONLY IN THE 50S. BY FRIDAY NIGHT A WEAK CUTOFF LOW WILL MOVE FROM THE FOUR CORNERS REGION INTO THE SOUTHERN PLAINS. CURRENT TRACK KEEPS MOISTURE AND BEST LARGE SCALE SUPPORT WELL SOUTH OF OUR CWA. WHILE THERE IS SOME ELEVATED INSTABILITY ACROSS SW KS THAT COULD SUPPORT A FEW SPRINKLES AS FAR NORTH AS WICHITA/GREELEY COUNTIES...CONFIDENCE IS IN CONDITIONS REMAINING DRY WITH THIS FEATURE FRIDAY NIGHT. .LONG TERM...(SATURDAY THROUGH TUESDAY) ISSUED AT 305 AM MDT WED OCT 23 2013 WARM WEEKEND AHEAD OF A STRONG COLD FRONT EARLY NEXT WEEK WHICH WILL BRING THE CHANCE FOR WINTRY PRECIP AND COLD TEMPS. SATURDAY AND SUNDAY WILL BE MILD WITH WEAK RIDGING MOVING ACROSS THE CENTRAL HIGH PLAINS LATE SATURDAY. SUNDAY WILL BE QUITE WARM WITH HIGHS IN THE 70S DUE TO WARM AIR ADVECTION AND FULL SUNSHINE. FAIRLY HIGH CONFIDENCE EARLY NEXT WEEK A STRONG COLD FRONT WILL SURGE SOUTH THROUGH THE HIGH PLAINS BRINGING MUCH COLDER AIR AND CHANCES FOR PRECIP. MODEL DIFFERENCES ARE STILL FAIRLY LARGE EVEN WHEN COMPARING MODELS RUN-TO-RUN...WITH LEAST CONFIDENCE IN PRECIP AND TIMING. THE COLD IS A DIFFERENT STORY WITH ALL GLOBAL GUIDANCE SHOWING A SURGE OF COLD AIR MOVING SOUTH BY MID-WEEK NEXT WEEK...BUT AGAIN WITH TIMING DIFFERENCES. GENERALLY LEFT THE MODEL BLEND AS-IS BESIDES INCREASING SOME POPS SLIGHTLY. AT THIS POINT IT LOOKS LIKE THE FRONT WILL PUSH THROUGH LATE MONDAY WITH PRECIP BEGINNING AS SNOW...THEN POSSIBLY CHANGING TO RAIN/SNOW MIX ON TUESDAY AFTERNOON. DID NOT SPEND TO MUCH TIME NIT-PICKING TIMING AND PTYPE AT THIS TIME RANGE DUE TO COARSE TIME RESOLUTION OF GRIDS AT THIS RANGE....AND AT THIS POINT IT LOOKS LIKE THE PTYPES SHOULD BE STRAIGHTFORWARD /RAIN AND SNOW/. THE 00Z GFS IS A LITTLE CONCERNING WITH A WARM LAYER ALOFT TUESDAY...BUT GIVEN THE COMPLEXITY OF THE SET-UP AM NOT CONCERNED ABOUT IT JUST YET. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1145 AM MDT WED OCT 23 2013 VFR CONDITIONS WILL CONTINUE THIS EVENING AT GLD AND MCK. WINDS WILL BECOME LIGHT AND VEER TO A NORTHEASTERLY/EASTERLY DIRECTION OVERNIGHT. SOME UNCERTAINTY REMAINS WITH THE POTENTIAL FOR FOG AND LOW STRATUS. THE NAM MOST AGGRESSIVE AT LOWERING CEILINGS/VISIBILITIES INTO THE IFR CATEGORY LATE TONIGHT AT GLD WITH CEILINGS APPROACHING MVFR AT MCK. THIS IS SUPPORTED BY THE GENERAL PATTERN FAVORING THIS TO OCCUR. FOR NOW...HAVE NOT LOWERED CEILINGS OR VISIBILITY FURTHER FROM PREVIOUS FORECAST...ALTHOUGH REDUCTIONS MAY BE NEEDED IN THE NEXT TAF ISSUANCE IF CONFIDENCE INCREASES. ANOTHER UNCERTAINTY IS THE DURATION OF THE EVENT WITH SOME POTENTIAL FOR MVFR CEILINGS TO LINGER WELL INTO THE MORNING AND PERHAPS MID DAY AT GLD. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...DR LONG TERM...JJM AVIATION...BRB
AREA FORECAST DISCUSSION
NWS CARIBOU ME
630 PM EDT WED OCT 23 2013 .SYNOPSIS... A SMALL AREA OF LOW PRESSURE WILL SLIDE WELL SOUTH OF THE REGION THIS EVENING. AN UPPER LEVEL TROUGH WILL BUILD INTO THE EAST FROM QUEBEC THURSDAY INTO FRIDAY. && .NEAR TERM /THROUGH THURSDAY/... 630 PM UPDATE...THE REGIONAL RADARS ARE LOOKING MORE LIKE LATE FALL THIS EVENING WITH LAKE EFFECT SHOWERS COMING OFF OF LAKES ERIE AND ONTARIO WITH A BAND OF RAIN CLIPPING CAPE COD AND THE ISLANDS FROM AN OFFSHORE STORM. THE MAIN FORECAST CHALLENGE TONIGHT WILL BE HOW MUCH...IF ANY...PRECIPITATION CLIPS THE DOWNEAST COAST LATE TONIGHT THROUGH EARLY THU MORNING. DO HAVE SOME CONCERN IN THAT THE HRRR BRINGS AT LEAST SOME LIGHT RAIN TO THE COAST AND THE SREF 6-HOUR POPS HAVE A 75 PCT CHANCE OF MEASURABLE RAIN ACROSS THE SOUTHEAST 1/4 OF THE CWA. FOR THIS UPDATE WILL BEEF UP THE POPS TO LIKELY OVER THE OUTER WATERS AND TO HIGH CHANCE ALONG THE COAST. IT IS STILL POSSIBLE THAT THE POPS MAY NEED TO BE ADJUSTED UP FURTHER WITH SUBSEQUENT UPDATE(S) THIS EVENING. OTHERWISE...THE PAST FEW HOURS OF OBSERVED DATA WAS LOADED WITH ONLY SOME MINOR TWEAKS TO THE REMAINING FORECAST ELEMENTS TONIGHT. PREVIOUS DISCUSSION... A SMALL WAVE OF LOW PRESSURE TRACKING WELL SOUTH OF THE AREA MAY BRING SOME LIGHT RAIN TO THE DOWNEAST COAST THIS EVENING. THE LOW WILL QUICKLY MOVE TO THE EAST, SOUTH OF NOVA SCOTIA LATER TONIGHT. HIGH PRESSURE BUILDING TOWARD THE EAST COAST IN COMBINATION WITH LOW PRESSURE OVER QUEBEC WILL BRING GUSTY WEST WINDS LATER TONIGHT INTO THURSDAY. THIS WILL USHER IN SOME VERY CHILLY AIR AS A LARGE UPPER LEVEL TROUGH MOVES IN. THURSDAY WILL LIKELY BEGIN PARTLY CLOUDY TO MOSTLY CLEAR AS A WEAK SURFACE RIDGE MOVES OVER. STRATOCUMULUS CLOUDS WILL THEN INCREASE FROM THE NORTHWEST THURSDAY AFTERNOON AS MOISTURE IN THE TROUGH BEGINS TO FLOW INTO THE REGION. SOME SHOWERS OF RAIN AND POSSIBLY WET SNOW IN THE HIGHER ELEVATIONS MAY AFFECT NORTHERN AND WESTERN AREAS LATE IN THE DAY. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... A TROF WILL CROSS THE REGION THURSDAY NIGHT...WITH ANOTHER TROF CROSSING THE REGION FRIDAY. MOSTLY CLOUDY SKIES ALONG WITH A SLIGHT CHANCE OF RAIN/SNOW SHOWERS ARE EXPECTED ACROSS THE NORTH AND MOUNTAINS THURSDAY NIGHT AND FRIDAY...WITH GENERALLY PARTLY CLOUDY SKIES DOWNEAST. HIGH PRESSURE WILL THEN BUILD EAST FRIDAY NIGHT WITH PARTLY CLOUDY SKIES NORTH AND PARTLY CLOUDY/MOSTLY CLEAR SKIES DOWNEAST. TEMPERATURES WILL BE AT NEAR NORMAL...TO SLIGHTLY BELOW NORMAL...LEVELS THURSDAY NIGHT THROUGH FRIDAY NIGHT. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... HIGH PRESSURE WILL CROSS THE REGION SATURDAY WHILE LOW PRESSURE TRACKING NORTHEAST FROM THE GREAT LAKES DRAWS A COLD/OCCLUDED FRONT TOWARD THE REGION. CLOUD COVER WILL INCREASE ACROSS THE REGION LATER SATURDAY IN ADVANCE OF THE COLD/OCCLUDED FRONT. THE COLD/OCCLUDED FRONT WILL THEN CROSS THE REGION SATURDAY NIGHT THROUGH SUNDAY. FORECAST SOUNDINGS INDICATE THAT TEMPERATURES ALOFT WOULD SUPPORT SNOW ACROSS MUCH OF THE FORECAST AREA SATURDAY NIGHT. HOWEVER...BOUNDARY LAYER TEMPERATURES WILL REMAIN MARGINAL FOR SNOW ACROSS MOSTLY NORTHERN/CENTRAL PORTIONS OF THE FORECAST AREA. EXPECT A RAIN/SNOW MIX COULD TRANSITION TO MOSTLY SNOW ACROSS NORTHERN PORTIONS OF THE FORECAST AREA SATURDAY NIGHT...WITH A RAIN/SNOW MIX ACROSS CENTRAL AREAS AND MOSTLY RAIN DOWNEAST. COULD HAVE LIGHT SNOW ACCUMULATIONS ACROSS NORTHERN AREAS LATER SATURDAY NIGHT PARTICULARLY ACROSS HIGHER TERRAIN AREAS. THE COLD/OCCLUDED FRONT WILL MOVE EAST EARLY SUNDAY WITH STEADIER PRECIPITATION ENDING. COULD THEN HAVE LINGERING RAIN SHOWERS ACROSS MOSTLY NORTHERN AREAS SUNDAY AFTERNOON...WITH A SLIGHT CHANCE OF RAIN/SNOW SHOWERS SUNDAY NIGHT. A COLD FRONT THEN CROSSES THE REGION MONDAY WITH A CHANCE OF RAIN/SNOW SHOWERS ACROSS MOSTLY THE NORTH/MOUNTAINS. HIGH PRESSURE WILL THEN CROSS THE REGION TUESDAY. UNCERTAINTY EXISTS TUESDAY NIGHT INTO WEDNESDAY REGARDING WHETHER A POSSIBLE COLD FRONT CROSSES THE REGION WITH A CHANCE OF SHOWERS OR WHETHER HIGH PRESSURE PERSISTS. TEMPERATURES WILL REMAIN AT NEAR NORMAL...TO SLIGHTLY BELOW NORMAL...LEVELS SATURDAY THROUGH WEDNESDAY. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... NEAR TERM: VFR CONDITIONS ARE EXPECTED ACROSS THE AREA TONIGHT AND THURSDAY. THERE IS THE POTENTIAL THAT THERE COULD BE A SHORT WINDOW OF MVFR CEILINGS AT KBHB OVERNIGHT IF THE AREA OF RAIN OFFSHORE MOVES INTO THE AREA. WINDS WILL BECOME GUSTY THURSDAY AS COOLER AIR MOVES IN. SHORT TERM: OCCASIONAL MVFR CONDITIONS ARE POSSIBLE ACROSS MOSTLY THE NORTH AND MOUNTAINS THURSDAY NIGHT INTO FRIDAY...WITH VFR CONDITIONS DOWNEAST. VFR CONDITIONS ARE EXPECTED ACROSS THE REGION FRIDAY NIGHT INTO SATURDAY. MVFR/IFR CONDITIONS ARE THEN EXPECTED ACROSS THE REGION SATURDAY NIGHT INTO EARLY SUNDAY. OCCASIONAL MVFR CONDITIONS WILL LINGER ACROSS THE NORTH AND MOUNTAINS SUNDAY NIGHT INTO MONDAY...WITH GENERALLY VFR CONDITIONS DOWNEAST. && .MARINE... NEAR TERM: A GALE WARNING WILL BE NEEDED FOR THE OFFSHORE WATERS FOR WEST WINDS GUSTING UP TO 35 KT THURSDAY AFTERNOON INTO THURSDAY EVENING. AN SCA WILL BE POSTED FOR THE INTRACOASTAL WATERS THURSDAY AFTERNOON. SHORT TERM: A GALE WARNING WILL REMAIN IN EFFECT FOR MUCH OF THE WATERS EARLY THURSDAY NIGHT. GENERALLY SMALL CRAFT CONDITIONS ARE THEN EXPECTED ACROSS THE WATERS LATER THURSDAY NIGHT INTO MONDAY. VISIBILITIES COULD BE REDUCED IN RAIN SATURDAY NIGHT INTO SUNDAY. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON THURSDAY TO MIDNIGHT EDT THURSDAY NIGHT FOR ANZ052. GALE WARNING FROM NOON THURSDAY TO MIDNIGHT EDT THURSDAY NIGHT FOR ANZ050-051. && $$ NEAR TERM...BLOOMER/CB SHORT TERM...NORCROSS LONG TERM...NORCROSS AVIATION...BLOOMER/CB/NORCROSS MARINE...BLOOMER/CB/NORCROSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
411 PM EDT WED OCT 23 2013 .SYNOPSIS... ISSUED AT 408 PM EDT WED OCT 23 2013 THE DEEP UPPER TROUGH AND ASSOCIATED COLD AIR WHICH MOVED OVER ONTARIO EARLIER THIS WEEK...WILL REMAIN NEARLY STATIONARY ACROSS THE GREAT LAKES THROUGH THE WEEKEND. THE UPPER TROUGH WILL COMBINE WITH A SERIES OF WEAKER STORM SYSTEMS FORECAST TO SWEEP OVER THE GREAT LAKES...TO GENERATE A WINTRY RAIN SNOW MIX OVER NORTHERN MICHIGAN THROUGH THE WEEKEND. TEMPERATURES WILL REMAIN NEARLY SEASONAL TO SLIGHTLY BELOW NORMAL INTO THE BEGINNING OF NEXT WEEK. && .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 408 PM EDT WED OCT 23 2013 CURRENTLY, THE SFC AND 500 MB LOWS ARE LOCATED EAST OF HUDSON BAY WITH THE VARIOUS TROUGHS AT 500 MB, AND THE SFC ROTATING AROUND THEM. THIS HAS CONTINUED THE NW FLOW LAKE EFFECT PATTERN OF THE LAST 2 DAYS. THE MAIN CONCERN WILL AGAIN BE THE PRECIPITATION TYPE OVERNIGHT AS THE LAKE INFLUENCE HASN`T BEEN MUCH TO SLOW THE SNOW MACHINE DOWN. TONIGHT...WHILE THERE HAS BEEN RAIN MIXED IN AT THE SHORELINES, THE MAJORITY OF THE DAY WAS SNOW SHOWERS IN THE HIGHER ELEVATIONS AND IN SAULT STE. MARIE. WHILE THE WARM AIR AND RAIN WAS SHOWING UP OVER WHITEFISH BAY, THE COOLER AIR STAYED IN AT ANJ WHERE THEY GOT 4.1 INCHES BY THE AFTERNOON. SO CONSIDERING THAT THE LES PATTERN WILL CONTINUE TO BE NW INTO THE SOO FOR THE EVENING, WILL PUT MORE SNOW INTO THE FORECAST THERE FOR THE EVENING AS THIS WINDS DOWN. THIS EVENING IN N LOWER, THE DIURNAL RAIN/SNOW MIX (AND IT IS MOSTLY RAIN) HAS BEEN FILLING THE RADAR THE LAST 2 HOURS WITH THE INSTABILITY OF THE -32C 500 MB AIR IS OVER US. ADD TO THAT THE 850 MB -6C AIR AND WE HAVE BEEN GETTING CALLS ABOUT GRAUPEL ALL AFTERNOON. ALL OF THIS WILL SETTLE DOWN ONCE THE SUN SETS AND THE LAKE EFFECT BANDS BECOME MORE ORGANIZED INTO THE NW FLOW PATTERN. DEPENDING ON HOW THIS TURNS OUT, THERE COULD BE LIGHT AMOUNTS IN NW LOWER. THERE IS A LOW PROBABILITY FOR A MODERATE AMOUNT OF SNOW, BUT THE MODELS ARE PRETTY BULLISH AT WARMING THINGS TO ABOVE -6C BY 0Z. OVERNIGHT, 850 MB WARM TO ABOVE -5C ON THE NAM/WRF ABOVE -6C ON THE GFS AND REMAINS BELOW -6C ON THE ECMWF. LOOKING AT THE HRRR ANALYSIS NORTH OF LAKE SUPERIOR AS A POCKET OF -4C AIR THAT SHOULD BE ROTATING SOUTH INTO THE UPPER GREAT LAKES OVERNIGHT. SO WILL GO WITH THE AVERAGE OF THE MODELS WITH THE -5C AIR. WE`LL SEE IF THIS IS RIGHT. IF THE TEMPERATURES WARM ENOUGH, THEN THE LAKES WILL HAVE MORE INFLUENCE IN THE LOWER LEVELS AND MORE RAIN WILL MIX IN OVERNIGHT. IF NOT, THEN THE SNOW AMOUNTS ARE ON THE LOW SIDE. BY 12Z THE FLOW SHOULD HAVE CHANGED TO A NNW FLOW PATTERN AND SHUT OFF AT ANJ AND WILL SHIFT SOME OF THE PRECIPITATION TOWARD THE WEST IN NW LOWER SO THAT IT IS CLOSER TO TVC. (10/24)THURSDAY...THE MODELS ALL SAY THAT THE NNW FLOW PATTERN REMAINS BUT NOW THE ECMWF HAS THE WARMER 850 MB TEMPERATURES (BELOW -6C. SO WILL MIX THE RAIN INTO THE SNOW AGAIN AND GO WITH ALL RAIN BY THE AFTERNOON. IF THE NAM IS RIGHT THERE COULD BE RAIN ALL DAY. IF THE GFS AND ECMWF ARE RIGHT THEN THERE WILL BE A BETTER MIX IN THE MORNING, WITH THE AFTERNOON TURNING OUT WITH LAKE EFFECT RAIN. I`M BANKING MORE TOWARD THE GFS/ECMWF SOLUTION AS THE NAM SEEMS TO BE THE OUTLIER IN THIS CASE. && .LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 408 PM EDT WED OCT 23 2013 RECENT TRENDS...TEMPERATURES: 1-2F BELOW NORMAL LAST SEVEN DAYS... BUT STILL SOLIDLY ABOVE AVERAGE FOR OCTOBER GIVEN OUR WARM FIRST HALF (2-4+F ABOVE). PRECIPITATION/HYDROLOGY: LAST 7 DAYS 100-200 PERCENT OF NORMAL MUCH OF NORTHERN LOWER...200-300+ PERCENT OF NORMAL ACROSS THE TIP OF THE MITT DUE TO RECENT LAKE EFFECT. DRIER ACROSS EASTERN UPPER (25-75 PERCENT OF NORMAL CHIPPEWA COUNTY). SIMILAR PERCENTAGES FOR TOTAL MONTH PRECIP DEPARTURES. RECENT WETTER CONDITIONS ACROSS THE TIP OF THE MITT ALSO EVIDENT IN 30 DAY STANDARDIZED PRECIP INDEX ANALYSIS...ALONG WITH SOME DRYNESS ACROSS EASTERN UPPER. RECENT PRECIP SURPLUS ALSO SHOWING UP IN ABOVE NORMAL STREAMFLOWS WITHIN THE JORDAN/CHEBOYGAN/THUNDER BAY RIVER BASINS. SYNOPSIS...AMPLIFIED LONG WAVE TROUGH AXIS ACROSS CENTRAL NORTH AMERICA...AND SUPPORTING +PNA RIDGE ALONG THE WEST COAST. PART OF A BALANCED FOUR WAVE HEMISPHERIC PATTERN. UPPER LAKES REMAIN UNDER THE INFLUENCE OF LOW PRESSURE OVER NORTHWEST QUEBEC...KEEPING SOME SEMBLANCE OF CYCLONIC FLOW IN PLACE WHICH IS HELPING TO DRIVE CONVECTIVE SHOWERS (BOTH OF THE LAKE AND DIURNAL VARIETY). SYNOPTIC PATTERN OVER THE NEXT WEEK DOESN`T CHANGE MUCH INITIALLY AS LONG WAVE FEATURES ARE PRETTY WELL ANCHORED IN PLACE. NORTHERN PORTION OF A SPLIT SHORT WAVE TROUGH CURRENTLY OUT AROUND 145W WILL CREST THE WEST COAST RIDGE AND DIG SOUTHEAST TOWARD THE UPPER MIDWEST/UPPER GREAT LAKES BY THIS WEEKEND...HELPING REINFORCE THE MEAN TROUGH POSITION. SOME CHANGES MAY BE IN THE OFFING FOR NEXT WEEK...LIKELY SOMEWHAT IN RESPONSE TO THE EXTRATROPICAL TRANSITION OF TYPHOON "FRANCISCO" WHICH HAS BEEN DRIFTING NORTHWEST TO THE SOUTH OF JAPAN OVER THE LAST 24 HOURS. AS THE REMNANTS OF THIS FEATURE GET ABSORBED INTO THE WESTERLIES...LOOKS AS IF IT WILL SEND A TRAIN OF ENERGY EAST ACROSS THE PACIFIC AND RESULTING IN A SHARP AMPLIFICATION OF RIDGING OVER THE NORTHEAST PACIFIC/WESTERN CANADA EARLY NEXT WEEK. THIS IN TURN WILL ALLOW HEIGHT FALLS TO DROP INTO THE WESTERN U.S...POSSIBLY IN THE FORM OF A SPLIT TROUGH WHICH COULD BRING THE GREAT LAKES INTO MORE WEST/SOUTHWEST FLOW ALOFT WITHIN SOUTHERN BRANCH OF THIS SPLIT. LOW LEVEL WINDS THROUGH THURSDAY LOOK TO STILL BE DOMINATED BY BROAD CYCLONIC CIRCULATION OVER EASTERN CANADA...AS A NARROW RIDGE OF HIGH PRESSURE SLIDES DOWN THE PLAINS AND INTO THE MIDDLE/LOWER MISSISSIPPI VALLEY BY FRIDAY. IN RESPONSE TO THIS...AND AHEAD OF A WEAK LOW ASSOCIATED WITH DIGGING SHORT WAVE ENERGY OVER CENTRAL CANADA...WINDS EXPECTED TO BACK SOUTHWEST AND WARM ADVECTION KICKS IN FOR FRIDAY. SHORT WAVE TROUGH FORECAST TO CROSS MICHIGAN SATURDAY WITH A QUICK REINFORCING PUSH OF COLDER AIR IN ITS WAKE. AS FLOW SPLITS OUT WEST EARLY NEXT WEEK...NORTHERN BRANCH SHORT WAVE TROUGH FORECAST TO PASS NORTH OF THE GREAT LAKES THOUGH MAY PUSH A COLD FRONT INTO THE REGION. STRONGER HEIGHT FALLS INTO THE WEST AS A COLD AIR MASS INVADES THE NORTHERN ROCKIES/INTERMOUNTAIN WEST. ASSOCIATED POLAR HIGH EXPANDS EAST TOWARD THE GREAT LAKES BY MIDWEEK AND SETS UP AN EXTENSIVE NORTH-SOUTH THERMAL GRADIENT ACROSS THE CENTRAL U.S. THIS AREA WILL NEED TO BE WATCHED TOWARD THE MIDDLE AND END OF NEXT WEEK FOR POTENTIAL DEVELOPMENT WITH A STRONG UPPER TROUGH OVER THE GREAT BASIN. THURSDAY NIGHT THROUGH FRIDAY NIGHT...NEAR TERM FORECAST ISSUES WILL CONTINUE TO DEAL WITH LINGERING LAKE CONVECTION AND IMPACTS OF DEVELOPING WARM ADVECTION PATTERN FRIDAY. THURSDAY NIGHT LOOKS LIKE MUCH OF THE SAME OF THE PAST SEVERAL DAYS WITH SYNOPTIC MOISTURE DROPPING IN FROM THE NORTH WITH COLD AIR IN PLACE AND INVERSION HEIGHTS STILL IN THE 700-800MB RANGE...SO MORE NORTHWEST FLOW LAKE EFFECT SHOWERS FOCUSED PRIMARILY ON EASTERN UPPER AND NORTHWEST LOWER (COVERAGE EXPECTED WANE DURING THE EVENING OVER SOUTHEAST PORTION OF THE FORECAST AREA ESPECIALLY WITH LOSS OF DIURNAL COMPONENT). PRECIPITATION TYPE SHOULD TRANSITION TOWARD MORE SNOW ESPECIALLY INLAND FROM LAKE MICHIGAN/WHITEFISH BAY...COUPLE INCHES OF SNOW A POSSIBILITY ACROSS PARTS OF NORTHWEST LOWER DEPENDING ON HOW ORGANIZED THINGS GET. BOUNDARY LAYER WINDS WILL BE BACKING FRIDAY...THOUGH RAIN/SNOW SHOWERS WILL BE ONGOING AT DAYBREAK FRIDAY AND MAY GET SOME AUGMENTATION OF COVERAGE THROUGH DIURNAL HEATING (GUIDANCE QPF IS DRIER THAN THIS IDEA...BUT GIVEN INERTIA ARGUMENTS AND THE TYPICAL TENDENCY TO END LAKE INDUCED PRECIPITATION TOO QUICKLY WILL NOT DRY THINGS OUT DURING THE AFTERNOON. IF IT ENDS...CONSIDER IT A BONUS). LOW LEVEL WARM ADVECTION EXPECTED TO STRENGTHEN FRIDAY NIGHT AS LOW LEVEL JET IMPINGES UPON THE UPPER GREAT LAKES TO THE SOUTH OF THE APPROACHING SURFACE LOW OUT OF NORTHWEST ONTARIO. EXPECT THIS TO SPREAD AN AREA OF PRECIPITATION ACROSS NORTHERN MICHIGAN STARTING FRIDAY EVENING...PROBABLY MOSTLY IN THE FORM OF RAIN THOUGH MAY START AS A MIX OR ALL SNOW ACROSS THE HIGHER TERRAIN OF NORTHERN LOWER. EXTENDED FORECAST (SATURDAY THROUGH WEDNESDAY)...SHARP THERMAL TROUGHING ASSOCIATED WITH SHORT WAVE TROUGH PASSAGE SATURDAY... COMBINED WITH SOME DEEPER LAYER SYNOPTIC MOISTURE EXPECTED TO TRANSITION THINGS BACK OVER TO MORE LAKE/DIURNAL CONVECTIVE SHOWERS DURING THE DAY. SHOULD BE A BREEZY DAY AS WELL WITH WINDS SWINGING BACK AROUND TO THE WEST/NORTHWEST. SUNDAY WILL SEE NEXT SHORT WAVE DIGGING SOUTHEAST ACROSS CENTRAL CANADA PUSHING THE NEXT COLD FRONT TOWARD THE UPPER LAKES. THERE IS UNCERTAINTY REGARDING TIMING OF THIS FEATURE AND HOW FAR SOUTH IT ULTIMATELY PUSHES BASED ON STRENGTH OF SURFACE RIDGE AXIS PUSHING EAST ACROSS CANADA. ECMWF MUCH MORE AGGRESSIVE AND PROBABLY NOT UNREASONABLE...GFS HAS BEEN GOING BACK AND FORTH OVER THE PAST THREE RUNS. AT LEAST FOR SUNDAY THERE SHOULD BE SOME RESIDUAL LAKE CONVECTION AROUND...BUT IF WE CAN SHOVE THE NEXT COLD FRONT FAR ENOUGH SOUTH MAY FINALLY GET AWAY WITH A SHOT AT A DRY DAY MONDAY. PATTERN SETS UP FAVORABLY FOR AN OVERRUNNING PRECIP EVENT HEADING INTO TUESDAY...POSSIBLY DRY TO START THE NEW WEDNESDAY FORECAST THOUGH PLENTY OF UNCERTAINTY DEPENDING ON HOW UPSTREAM ENERGY EVOLVES (AND WITH TYPHOON EXTRATROPICAL TRANSITION GETTING INVOLVED...PLENTY OF CHANGES LIKELY). TEMPERATURES TO REMAIN BELOW NORMAL THROUGH THE EXTENDED PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 244 PM EDT WED OCT 23 2013 SNOW AND RAIN SHOWERS HAVE BEEN HITTING THE REGION, BUT FOR THE MOST PART THE CIGS HAVE BEEN REMAINING MAINLY VFR WITH A FEW MVFR CIGS. THE VSBYS HAVE BEEN MAINLY VFR WITH A FEW MVFR VSBYS. THIS WILL CONTINUE TO BE THE CASE INTO THE EVENING AS THE RAIN SHOWERS INCREASE IN COVERAGE, AND CHANGE BACK OVER TO SNOW TONIGHT. THERE WILL BE A LITTLE MORE RAIN MIXED IN OVERNIGHT AS WARMER TEMPERATURES ARE EXPECTED. && .MARINE... ISSUED AT 408 PM EDT WED OCT 23 2013 THE WINDS TOOK A BIT OF TIME TO START GUSTING TODAY DUE TO THE WEAK GRADIENT, BUT ARE EXPECTED TO INCREASE A BIT TONIGHT AS THE NEXT SFC TROUGH ROTATES INTO THE UPPER GREAT LAKES. HOWEVER, THE MAIN CONCERN WILL BE THE WAVES OVER THE NEXT 36 HOURS AS THE NW WIND WILL CONTINUE TO KEEP WAVE HEIGHT OVER 4 FEET WHICH IS SMALL CRAFT CRITERIA. FRIDAY, IT LOOKS LIKE THE GRADIENT SLACKENS SO THAT THE WINDS WILL DIMINISH AND THE WAVES WILL SUBSIDE. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LHZ346. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR LHZ345-347>349. LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ341. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR LMZ323-342- 344>346. LS...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LSZ322. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR LSZ321. && $$ SYNOPSIS...SWR SHORT TERM...JSL LONG TERM...JPB AVIATION...JSL MARINE...JSL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
302 PM EDT WED OCT 23 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 439 AM EDT WED OCT 23 2013 THE CWA IS UNDER THE WESTERN SIDE OF AN UPPER TROUGH COVERING THE THE GREAT LAKES REGION. THIS TROUGH IS ALLOWING COLD AIR TO SURGE SOUTH OVER THE AREA AND LEAD TO BELOW NORMAL TEMPERATURES OVER THE LAST COUPLE OF DAYS. AT THE SURFACE...A NEARLY STATIONARY LOW EAST OF JAMES BAY AND A HIGH PRESSURE RIDGE STRETCHING FROM THE CANADIAN PRAIRIES INTO THE NORTHERN PLAINS WILL CONTINUE TO PRODUCE NORTHWESTERLY FLOW OVER THE AREA OVER THE NEXT 24-36HRS. SNOW SHOWERS ACROSS THE AREA ARE FAIRLY DISORGANIZED AND BLOTCHY EARLY THIS MORNING AS WINDS HAVE BEEN BOUNCING AROUND DURING THE OVERNIGHT HOURS (DUE TO LAND BREEZES AND WEAK SURFACE TROUGH STRETCHING ACROSS THE WESTERN LAKE). THIS DISORGANIZATION IS ALSO LIKELY DUE TO MODELS SHOWING DEEPER MOISTURE TO BE LACKING OVER MUCH OF THE AREA AT THIS TIME (EVEN THOUGH 850MB TEMPS ANALYZED ON THE RAP ARE -8C). THE LAST HOUR OR SO HAS SEEN A SLIGHT INCREASE IN COVERAGE AND INTENSITY...LARGELY DUE TO THE POCKET OF MOISTURE THAT IS SLIDING OUT OF NORTHEAST MINNESOTA AND ASSOCIATED WITH WEAK SHORTWAVE ENERGY. THIS TREND WILL PROBABLY CONTINUE THROUGH THE NEXT COUPLE HOURS AND HAVE TRENDED POPS UP (FROM CURRENT SCATTERED COVERAGE) THROUGH THE MID MORNING HOURS. STRONGEST SHOWERS WILL LIKELY BE EAST OF MUNISING AND POTENTIALLY FOCUSED IN GOGEBIC/ONTONAGON COUNTIES WITH WINDS TRYING TO BACK SLIGHTLY AHEAD OF THE WEAK LAKE INDUCED SURFACE TROUGH OVER THE WESTERN LAKE EARLY THIS MORNING. HIGH RESOLUTION MODELS PICKING UP ON THIS IDEA IN THEIR PRECIP/REFLECTIVITY FIELDS AND LEADS TO INCREASED CONFIDENCE. ONCE DAYTIME HEATING TAKES HOLD AND POCKET OF DRIER AIR ALONG THE MINNESOTA/CANADA BORDER DROPS OVER THE AREA...THINK THE SHOWERS WILL DIMINISH SOME...ESPECIALLY OVER THE WEST WHERE THE FETCH IS SHORTER. ONE OTHER ITEM FOR THIS AFTERNOON...HELD ONTO SOME POPS OVER THE SOUTH CENTRAL...EVEN THOUGH THAT ISN/T A FAVORABLE LOCATION FOR LAKE EFFECT. FELT HAVING SLIGHT CHANCES WAS REASONABLE WITH THE MOISTURE AVAILABLE AND STEEPENING LAPSE RATES (SFC-850MB VALUES AROUND 9C/KM) WITH THE COLD AIR ALOFT. THIS SHOULD BE ENOUGH FOR SOME CONVECTIVE CLOUD DEVELOPMENT AND MAYBE A FEW SHOWERS WITH THE INCREASING MOISTURE. THAT POCKET OF DRIER AIR WILL DEPART AS A SHORTWAVE DROPS SOUTH FROM ONTARIO THIS AFTERNOON AND EVENING. THIS BRINGS ADDITIONAL LOW-MID LEVEL MOISTURE WITH IT AND WILL AID THE LAKE EFFECT SHOWERS THAT WILL BE ONGOING. IT WILL ALSO BRING ABOUT A SLIGHT WIND SHIFT TO MORE OF A NORTH-NORTHWEST DIRECTION AND PUSH THE ONGOING LAKE EFFECT SHOWERS TO THE WEST. BEST MOISTURE IS OVER THE EASTERN CWA...SO WOULD EXPECT THE STRONGEST SHOWERS THERE WITH THE GREATEST FETCH. MODELS ARE INDICATING THE WINDS SHIFT AIDING A DOMINATE BAND OVER THE EAST DURING THE EVENING (INITIALLY OVER FAR EASTERN LAKE SUPERIOR AND THEN SHIFTING SOUTHWEST TOWARDS GRAND MARAIS) WHICH WILL BE ASSISTED BY MOISTENING OFF LAKE NIPIGON. ONE NEGATIVE WITH THIS SHORTWAVE IS THAT IT DOES PULL SLIGHTLY WARMER 850MB TEMPS OVER THE AREA TONIGHT...RISING SLIGHTLY FROM -8C TODAY TO -6/-7C TONIGHT OVER THE EAST. THIS LEADS TO INCREASING LOW LEVEL TEMPS AND RISING WETBULB ZERO VALUES. 00Z NAM/GFS BUFKIT SOUNDINGS FOR KERY SHOW WETBULB ZERO VALUES RISING TO ALMOST 1.5KFT BY DAYBREAK...WHICH WOULD BE PRETTY MUCH RAIN. ALSO...MUNISING STAYED RIGHT AROUND 41 DEGREES EARLY THIS MORNING UNTIL THE LAND BREEZE KICKED IN AND SHIFTED THE WINDS TO THE SOUTHWEST (TEMP DROPPED TO 36 DEGREES). SINCE THE GRADIENT SHOULD BE TIGHTER TONIGHT...THINK THAT WILL KEEP TEMPS UP RIGHT ALONG THE SHORELINE. THEREFORE...AFTER SNOW DURING THE DAY...HAVE TRENDED TOWARDS A MIX OF RAIN/SNOW EAST OF A LINE FROM MUNISING TO MANISTIQUE. AS FOR SNOW AMOUNTS...THE RAIN/SNOW MIX CREATES UNCERTAINTY ALONG WITH SNOW RATIOS. HAVE KEPT SNOW RATIOS LOWER...TOWARDS 10-1...SINCE THE BEST FORCING CONTINUES TO BE BELOW THE DGZ AND ONLY THE TOP OF THE CLOUD IS WITHIN THE DGZ. AS WAS SEEN TODAY...THERE WILL PROBABLY BE PERIODS OF FLAKES AND ALSO SNOW GRAINS/PELLETS IN THE STRONGER SHOWERS DUE TO THE STRONG LIFT OF SUPER COOLED WATER RUNNING INTO THE SMALLER FLAKES ALOFT. FOR EXAMPLE...TODAY AT OUR OFFICE WE HAD 0.53 INCH OF LIQUID BUT THE SNOWFALL TOTAL WAS 2.2 INCHES. THUS...WONDERING IF THE CURRENT 10-1 FORECAST IS A LITTLE TOO HIGH OVER THE EAST AND MAY BE CLOSER TO A 7/8 TO 1. AS FOR SNOWFALL TOTALS...KEPT AMOUNTS AROUND AN INCH IN THE NW SNOW BELTS FOR TODAY (WITH LOCALIZED HIGHER AMOUNTS NEAR IRONWOOD AND THE PORKIES). THEN FOR TONIGHT...HAVE A GENERAL 1-3IN FOR THE SAME LOCATIONS...BUT LESSER AMOUNTS WHERE THE RAIN/SNOW MIX IS. SOME CONCERN FOR NEAR ADVISORY LEVEL SNOWFALL TONIGHT OVER THE EAST WITH THE DOMINATE BAND. BUT WITH THE UNCERTAINTY ON SNOW TYPE (FLAKE VS PELLET) AND ALSO SOME RAIN MIXING IN NEAR THE SHORELINE...DIDN/T HAVE ENOUGH CONFIDENCE TO ISSUE ONE FOR ALGER COUNTY AREA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 503 AM EDT WED OCT 23 2013 A BLOCKING RIDGE FROM THE ERN PACIFIC INTO WEST COAST WILL KEEP THE BROAD DOWNSTREAM TROUGH IN PLACE OVER THE CNTRL AND ERN CONUS THROUGH THE FCST PERIOD WITH CONTINUED BELOW NORMAL TEMPERATURES. SHORTWAVE TROUGHS IN THE NW FLOW THROUGH THE UPPER GREAT LAKES WILL SUPPORT PERIODS OF INCREASED LAKE EFFECT PCPN. THURSDAY...WITH 850 MB TEMPS AROUND -6C TO -7C AND 700 MB TEMPS AROUND -13C...INSTABILITY WILL REMAIN HIGH ENOUGH TO KEEP LAKE EFFECT PCPN GOING FOR LOCATIONS FAVORED BY NW FLOW. THE HIGHER RES MODELS INDICATED THAT A MORE DOMINANT BAND ORIGINATING OFF OF LAKE NIPIGON MAY DEVELOP THAT WOULD AFFECT THE AREA FROM NEAR MUNISING AND PICTURED ROCKS TO MANISTIQUE. EVEN THOUGH LOCAL QPF VALUES MAY APPROACH A QUARTER INCH...THE LONG FETCH ACROSS THE RELATIVELY WARM LAKE MAY BRING ENOUGH MARINE INFLUENCE (MODEL WET-BULB ZERO HEIGHTS 1000-1500 FT) TO BRING MAINLY RAIN NEAR THE SHORE AND A RAIN/SNOW/GRAUPEL MIX FARTHER INLAND. SNOW/WATER RATIOS ARE LIKELY TO BE LOW AS THE GREATEST UPWARD MOTION IS EXPECTED WELL BELOW THE 8K-10K FT DGZ. SNOW SHOWERS WILL ALSO CONTINUE INTO WRN UPPER MI BUT WITH SNOWFALL AMOUNTS AT OR BELOW AN INCH GIVEN THE SHORTER FETCH AND APPROACH OF MORE ACYC FLOW WITH THE RIDGE MOVING INTO THE UPPER MS VALLEY. THU NIGHT...WITH A WEAKER WIND FIELD...LAKE INDUCED TROUGHING WILL HELP TO KEEP THE FOCUS OF LAKE EFFECT PCPN FROM NEAR MUNISING INTO NW SCHOOLCRAFT COUNTY. LOW LEVEL TEMPS WILL REMAIN WARM ENOUGH TO SUPPORT A RAIN/SNOW MIX WHICH SHOULD LIMIT SNOW ACCUMULATIONS TO AN INCH OR LESS. OVER THE WEST...SNOW SHOWERS WILL BECOME SCATTERED AND DIMINISH AS INVERSION HEIGHT DROP AND DRIER AIR EDGES IN. FRI INTO SAT...THE GFS/ECMWF WERE IN GOOD AGREEMENT WITH THE CLIPPER SHORTWAVE TROUGH AND SFC LOW MOVING THROUGH THE NRN GREAT LAKES. THE GREATEST 285K-295K ISENTROPIC LIFT AND ASSOCIATED PCPN BAND AHEAD OF THE LOW IS EXPECTED TO MOVE THROUGH THE EAST HALF OF LAKE SUPERIOR AND UPPER MICHIGAN FRI NIGHT. CAA BEHIND THE LOW DROPPING 850 MB TEMPS BACK TO -7C WILL BRING ANOTHER ROUND OF LAKE EFFECT PCPN FOR NW FLOW FAVORED LOCATIONS FROM SAT AFTERNOON INTO SAT NIGHT. LOW LEVEL TEMPS WILL BE WARM ENOUGH FOR A RAIN/SNOW MIX...EXCEPT OVER THE HIGHER TERRAIN OF THE WEST HALF. SUN-TUE...MODEL DIFFERENCES BECOME MORE SIGNIFICANT. THE ECMWF IS FASTER WITH THE NEXT SHORTWAVE AND PUSHES LOWER HEIGHTS AND CONFLUENCE ZONE FARTHER SOUTH COMPARED TO THE GFS/GEM. SO...FCST CONFIDENCE IN LOCATION OF EVOLUTION OF PCPN CHANCES ASSOCIATED WITH THE DEVELOPING 800-600 FGEN ZONE MON AND AREA OF WAA ISENTROPIC LIFT INTO TUE IS LOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 239 PM EDT WED OCT 23 2013 COOL NW WINDS WILL CONTINUE...BRINGING LAKE EFFECT SNOW SHOWERS TO NW SNOW BELTS OF UPPER MI /MAINLY IMPACTING IWD AND CMX/. DEEPER MOISTURE SET UP ACROSS N MN AND N LAKE SUPERIOR WILL CONTINUE TO SINK ACROSS THE REST OF THE AREA...WITH BORDERLINE VFR/MVFR CEILINGS FALLING TO MVFR AND REMAINING THERE THROUGH THURSDAY MORNING. CEILINGS AND VIS WILL FALL TO IFR IN STRONGER SNOW BANDS...MOST LIKELY AT IWD GIVEN THE BRIEF NW TO SLIGHTLY MORE NNW SHIFT IN THE WINDS OVERNIGHT. TEMPERATURES ALOFT WILL AND AT THE SFC WILL WARM SLIGHTLY THROUGH THURSDAY MORNING...WITH A RETURN TO MAINLY MVFR CEILINGS/VIS BY LATE MORNING. && .MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 302 PM EDT WED OCT 23 2013 A SLIGHT CHANCE OF WATERSPOUTS WILL CONTINUE OVER SE LAKE SUPERIOR THROUGH TONIGHT. OTHERWISE...LOW PRESSURE WILL SHIFT ACROSS QUEBEC OVERNIGHT INTO THURSDAY. THIS WILL ALLOW HIGH PRESSURE OVER SOUTHERN CANADA AND THE DAKOTAS TO SINK ACROSS THE MID MISSISSIPPI VALLEY BY FRIDAY MORNING...WITH A RIDGE PUSHING ACROSS LAKE SUPERIOR THURSDAY NIGHT THROUGH FRIDAY MORNING. NW WINDS GUSTS OF 20-30KTS WILL CONTINUE THROUGH THURSDAY EVENING. LOW PRESSURE OVER MANITOBA FRIDAY. AHEAD OF THE LOW SW GUSTS NEAR 25-30KTS WILL BE POSSIBLE LATE FRIDAY AFTERNOON/EVENING. THE LOW WILL DIVE ACROSS LAKE SUPERIOR OVERNIGHT INTO SUNDAY MORNING...BEFORE EXITING INTO SOUTHERN CANADA SATURDAY AFTERNOON INTO SOUTHERN QUEBEC OVERNIGHT. HIGH PRESSURE DROPPING FROM THE NORTHERN PLAINS TO THE MID MISSISSIPPI VALLEY SATURDAY AND SUNDAY WILL BRING A RIDGE ACROSS LAKE SUPERIOR SUNDAY. EXPECT NW GUSTS TO INCREASE AGAIN SATURDAY OUT OF THE NW 20-30KTS. LOW PRESSURE WILL ORGANIZE ACROSS THE CENTRAL AND SOUTHERN PLAINS MONDAY...AS STRONG HIGH PRESSURE OVER WESTERN CANADA MOVES ACROSS SOUTH CENTRAL CANADA AND BRINGS A RIDGE ACROSS LAKE SUPERIOR. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...JLB AVIATION...KF MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
240 PM EDT WED OCT 23 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 439 AM EDT WED OCT 23 2013 THE CWA IS UNDER THE WESTERN SIDE OF AN UPPER TROUGH COVERING THE THE GREAT LAKES REGION. THIS TROUGH IS ALLOWING COLD AIR TO SURGE SOUTH OVER THE AREA AND LEAD TO BELOW NORMAL TEMPERATURES OVER THE LAST COUPLE OF DAYS. AT THE SURFACE...A NEARLY STATIONARY LOW EAST OF JAMES BAY AND A HIGH PRESSURE RIDGE STRETCHING FROM THE CANADIAN PRAIRIES INTO THE NORTHERN PLAINS WILL CONTINUE TO PRODUCE NORTHWESTERLY FLOW OVER THE AREA OVER THE NEXT 24-36HRS. SNOW SHOWERS ACROSS THE AREA ARE FAIRLY DISORGANIZED AND BLOTCHY EARLY THIS MORNING AS WINDS HAVE BEEN BOUNCING AROUND DURING THE OVERNIGHT HOURS (DUE TO LAND BREEZES AND WEAK SURFACE TROUGH STRETCHING ACROSS THE WESTERN LAKE). THIS DISORGANIZATION IS ALSO LIKELY DUE TO MODELS SHOWING DEEPER MOISTURE TO BE LACKING OVER MUCH OF THE AREA AT THIS TIME (EVEN THOUGH 850MB TEMPS ANALYZED ON THE RAP ARE -8C). THE LAST HOUR OR SO HAS SEEN A SLIGHT INCREASE IN COVERAGE AND INTENSITY...LARGELY DUE TO THE POCKET OF MOISTURE THAT IS SLIDING OUT OF NORTHEAST MINNESOTA AND ASSOCIATED WITH WEAK SHORTWAVE ENERGY. THIS TREND WILL PROBABLY CONTINUE THROUGH THE NEXT COUPLE HOURS AND HAVE TRENDED POPS UP (FROM CURRENT SCATTERED COVERAGE) THROUGH THE MID MORNING HOURS. STRONGEST SHOWERS WILL LIKELY BE EAST OF MUNISING AND POTENTIALLY FOCUSED IN GOGEBIC/ONTONAGON COUNTIES WITH WINDS TRYING TO BACK SLIGHTLY AHEAD OF THE WEAK LAKE INDUCED SURFACE TROUGH OVER THE WESTERN LAKE EARLY THIS MORNING. HIGH RESOLUTION MODELS PICKING UP ON THIS IDEA IN THEIR PRECIP/REFLECTIVITY FIELDS AND LEADS TO INCREASED CONFIDENCE. ONCE DAYTIME HEATING TAKES HOLD AND POCKET OF DRIER AIR ALONG THE MINNESOTA/CANADA BORDER DROPS OVER THE AREA...THINK THE SHOWERS WILL DIMINISH SOME...ESPECIALLY OVER THE WEST WHERE THE FETCH IS SHORTER. ONE OTHER ITEM FOR THIS AFTERNOON...HELD ONTO SOME POPS OVER THE SOUTH CENTRAL...EVEN THOUGH THAT ISN/T A FAVORABLE LOCATION FOR LAKE EFFECT. FELT HAVING SLIGHT CHANCES WAS REASONABLE WITH THE MOISTURE AVAILABLE AND STEEPENING LAPSE RATES (SFC-850MB VALUES AROUND 9C/KM) WITH THE COLD AIR ALOFT. THIS SHOULD BE ENOUGH FOR SOME CONVECTIVE CLOUD DEVELOPMENT AND MAYBE A FEW SHOWERS WITH THE INCREASING MOISTURE. THAT POCKET OF DRIER AIR WILL DEPART AS A SHORTWAVE DROPS SOUTH FROM ONTARIO THIS AFTERNOON AND EVENING. THIS BRINGS ADDITIONAL LOW-MID LEVEL MOISTURE WITH IT AND WILL AID THE LAKE EFFECT SHOWERS THAT WILL BE ONGOING. IT WILL ALSO BRING ABOUT A SLIGHT WIND SHIFT TO MORE OF A NORTH-NORTHWEST DIRECTION AND PUSH THE ONGOING LAKE EFFECT SHOWERS TO THE WEST. BEST MOISTURE IS OVER THE EASTERN CWA...SO WOULD EXPECT THE STRONGEST SHOWERS THERE WITH THE GREATEST FETCH. MODELS ARE INDICATING THE WINDS SHIFT AIDING A DOMINATE BAND OVER THE EAST DURING THE EVENING (INITIALLY OVER FAR EASTERN LAKE SUPERIOR AND THEN SHIFTING SOUTHWEST TOWARDS GRAND MARAIS) WHICH WILL BE ASSISTED BY MOISTENING OFF LAKE NIPIGON. ONE NEGATIVE WITH THIS SHORTWAVE IS THAT IT DOES PULL SLIGHTLY WARMER 850MB TEMPS OVER THE AREA TONIGHT...RISING SLIGHTLY FROM -8C TODAY TO -6/-7C TONIGHT OVER THE EAST. THIS LEADS TO INCREASING LOW LEVEL TEMPS AND RISING WETBULB ZERO VALUES. 00Z NAM/GFS BUFKIT SOUNDINGS FOR KERY SHOW WETBULB ZERO VALUES RISING TO ALMOST 1.5KFT BY DAYBREAK...WHICH WOULD BE PRETTY MUCH RAIN. ALSO...MUNISING STAYED RIGHT AROUND 41 DEGREES EARLY THIS MORNING UNTIL THE LAND BREEZE KICKED IN AND SHIFTED THE WINDS TO THE SOUTHWEST (TEMP DROPPED TO 36 DEGREES). SINCE THE GRADIENT SHOULD BE TIGHTER TONIGHT...THINK THAT WILL KEEP TEMPS UP RIGHT ALONG THE SHORELINE. THEREFORE...AFTER SNOW DURING THE DAY...HAVE TRENDED TOWARDS A MIX OF RAIN/SNOW EAST OF A LINE FROM MUNISING TO MANISTIQUE. AS FOR SNOW AMOUNTS...THE RAIN/SNOW MIX CREATES UNCERTAINTY ALONG WITH SNOW RATIOS. HAVE KEPT SNOW RATIOS LOWER...TOWARDS 10-1...SINCE THE BEST FORCING CONTINUES TO BE BELOW THE DGZ AND ONLY THE TOP OF THE CLOUD IS WITHIN THE DGZ. AS WAS SEEN TODAY...THERE WILL PROBABLY BE PERIODS OF FLAKES AND ALSO SNOW GRAINS/PELLETS IN THE STRONGER SHOWERS DUE TO THE STRONG LIFT OF SUPER COOLED WATER RUNNING INTO THE SMALLER FLAKES ALOFT. FOR EXAMPLE...TODAY AT OUR OFFICE WE HAD 0.53 INCH OF LIQUID BUT THE SNOWFALL TOTAL WAS 2.2 INCHES. THUS...WONDERING IF THE CURRENT 10-1 FORECAST IS A LITTLE TOO HIGH OVER THE EAST AND MAY BE CLOSER TO A 7/8 TO 1. AS FOR SNOWFALL TOTALS...KEPT AMOUNTS AROUND AN INCH IN THE NW SNOW BELTS FOR TODAY (WITH LOCALIZED HIGHER AMOUNTS NEAR IRONWOOD AND THE PORKIES). THEN FOR TONIGHT...HAVE A GENERAL 1-3IN FOR THE SAME LOCATIONS...BUT LESSER AMOUNTS WHERE THE RAIN/SNOW MIX IS. SOME CONCERN FOR NEAR ADVISORY LEVEL SNOWFALL TONIGHT OVER THE EAST WITH THE DOMINATE BAND. BUT WITH THE UNCERTAINTY ON SNOW TYPE (FLAKE VS PELLET) AND ALSO SOME RAIN MIXING IN NEAR THE SHORELINE...DIDN/T HAVE ENOUGH CONFIDENCE TO ISSUE ONE FOR ALGER COUNTY AREA. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 503 AM EDT WED OCT 23 2013 A BLOCKING RIDGE FROM THE ERN PACIFIC INTO WEST COAST WILL KEEP THE BROAD DOWNSTREAM TROUGH IN PLACE OVER THE CNTRL AND ERN CONUS THROUGH THE FCST PERIOD WITH CONTINUED BELOW NORMAL TEMPERATURES. SHORTWAVE TROUGHS IN THE NW FLOW THROUGH THE UPPER GREAT LAKES WILL SUPPORT PERIODS OF INCREASED LAKE EFFECT PCPN. THURSDAY...WITH 850 MB TEMPS AROUND -6C TO -7C AND 700 MB TEMPS AROUND -13C...INSTABILITY WILL REMAIN HIGH ENOUGH TO KEEP LAKE EFFECT PCPN GOING FOR LOCATIONS FAVORED BY NW FLOW. THE HIGHER RES MODELS INDICATED THAT A MORE DOMINANT BAND ORIGINATING OFF OF LAKE NIPIGON MAY DEVELOP THAT WOULD AFFECT THE AREA FROM NEAR MUNISING AND PICTURED ROCKS TO MANISTIQUE. EVEN THOUGH LOCAL QPF VALUES MAY APPROACH A QUARTER INCH...THE LONG FETCH ACROSS THE RELATIVELY WARM LAKE MAY BRING ENOUGH MARINE INFLUENCE (MODEL WET-BULB ZERO HEIGHTS 1000-1500 FT) TO BRING MAINLY RAIN NEAR THE SHORE AND A RAIN/SNOW/GRAUPEL MIX FARTHER INLAND. SNOW/WATER RATIOS ARE LIKELY TO BE LOW AS THE GREATEST UPWARD MOTION IS EXPECTED WELL BELOW THE 8K-10K FT DGZ. SNOW SHOWERS WILL ALSO CONTINUE INTO WRN UPPER MI BUT WITH SNOWFALL AMOUNTS AT OR BELOW AN INCH GIVEN THE SHORTER FETCH AND APPROACH OF MORE ACYC FLOW WITH THE RIDGE MOVING INTO THE UPPER MS VALLEY. THU NIGHT...WITH A WEAKER WIND FIELD...LAKE INDUCED TROUGHING WILL HELP TO KEEP THE FOCUS OF LAKE EFFECT PCPN FROM NEAR MUNISING INTO NW SCHOOLCRAFT COUNTY. LOW LEVEL TEMPS WILL REMAIN WARM ENOUGH TO SUPPORT A RAIN/SNOW MIX WHICH SHOULD LIMIT SNOW ACCUMULATIONS TO AN INCH OR LESS. OVER THE WEST...SNOW SHOWERS WILL BECOME SCATTERED AND DIMINISH AS INVERSION HEIGHT DROP AND DRIER AIR EDGES IN. FRI INTO SAT...THE GFS/ECMWF WERE IN GOOD AGREEMENT WITH THE CLIPPER SHORTWAVE TROUGH AND SFC LOW MOVING THROUGH THE NRN GREAT LAKES. THE GREATEST 285K-295K ISENTROPIC LIFT AND ASSOCIATED PCPN BAND AHEAD OF THE LOW IS EXPECTED TO MOVE THROUGH THE EAST HALF OF LAKE SUPERIOR AND UPPER MICHIGAN FRI NIGHT. CAA BEHIND THE LOW DROPPING 850 MB TEMPS BACK TO -7C WILL BRING ANOTHER ROUND OF LAKE EFFECT PCPN FOR NW FLOW FAVORED LOCATIONS FROM SAT AFTERNOON INTO SAT NIGHT. LOW LEVEL TEMPS WILL BE WARM ENOUGH FOR A RAIN/SNOW MIX...EXCEPT OVER THE HIGHER TERRAIN OF THE WEST HALF. SUN-TUE...MODEL DIFFERENCES BECOME MORE SIGNIFICANT. THE ECMWF IS FASTER WITH THE NEXT SHORTWAVE AND PUSHES LOWER HEIGHTS AND CONFLUENCE ZONE FARTHER SOUTH COMPARED TO THE GFS/GEM. SO...FCST CONFIDENCE IN LOCATION OF EVOLUTION OF PCPN CHANCES ASSOCIATED WITH THE DEVELOPING 800-600 FGEN ZONE MON AND AREA OF WAA ISENTROPIC LIFT INTO TUE IS LOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 239 PM EDT WED OCT 23 2013 COOL NW WINDS WILL CONTINUE...BRINGING LAKE EFFECT SNOW SHOWERS TO NW SNOW BELTS OF UPPER MI /MAINLY IMPACTING IWD AND CMX/. DEEPER MOISTURE SET UP ACROSS N MN AND N LAKE SUPERIOR WILL CONTINUE TO SINK ACROSS THE REST OF THE AREA...WITH BORDERLINE VFR/MVFR CEILINGS FALLING TO MVFR AND REMAINING THERE THROUGH THURSDAY MORNING. CEILINGS AND VIS WILL FALL TO IFR IN STRONGER SNOW BANDS...MOST LIKELY AT IWD GIVEN THE BRIEF NW TO SLIGHTLY MORE NNW SHIFT IN THE WINDS OVERNIGHT. TEMPERATURES ALOFT WILL AND AT THE SFC WILL WARM SLIGHTLY THROUGH THURSDAY MORNING...WITH A RETURN TO MAINLY MVFR CEILINGS/VIS BY LATE MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 439 AM EDT WED OCT 23 2013 WITH THE UPPER GREAT LAKES BETWEEN A LOW OVER WESTERN QUEBEC AND A HIGH PRESSURE RIDGE STRETCHING FROM THE CANADIAN PRAIRIES AND INTO THE NORTHERN PLAINS...EXPECT PERSISTENT NORTHWEST WINDS OF 15-25KTS THROUGH THURSDAY. THERE COULD BE SOME GUSTS TO 30KTS OVER THE EAST TONIGHT AS THE PRESSURE GRADIENT TIGHTENS SLIGHTLY. WINDS ARE EXPECTED TO DIMINISH AND BACK ON THURSDAY NIGHT AND FRIDAY...AS A HIGH PRESSURE RIDGE MOVES THROUGH THE UPPER GREAT LAKES. A CLIPPER SYSTEM WILL DIVE SOUTHEAST OUT OF CANADA ON FRIDAY NIGHT AND MOVE ACROSS EASTERN LAKE SUPERIOR. THIS WILL ONCE AGAIN SHIFT WINDS BACK TO THE NORTHWEST UP TO 30KTS FOR SATURDAY AND SATURDAY NIGHT...ESPECIALLY OVER EASTERN LAKE SUPERIOR. A HIGH PRESSURE RIDGE WILL MOVE BACK INTO THE GREAT LAKES FOR SUNDAY...DECREASING THE WINDS BELOW 20KTS. FINALLY...WILL CONTINUE TO MENTION A SLIGHT CHANCE FOR WATERSPOUTS OVER THE SOUTHEAST PART OF LAKE SUPERIOR FOR THIS AFTERNOON INTO TONIGHT. WATERSPOUT NOMOGRAM INDICATES BORDERLINE POTENTIAL...BUT WITH STRONGER LAKE EFFECT SHOWERS OCCURRING DURING THAT TIME...FELT IT WAS WARRENTED TO KEEP IN. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...SRF LONG TERM...JLB AVIATION...KF MARINE...SRF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1243 PM CDT WED OCT 23 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 255 AM CDT WED OCT 23 2013 CURRENT WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES LOOK QUITE FAMILIAR...GIVEN THAT THE LARGE SCALE PATTERN HASN/T CHANGED MUCH IN THE PAST SEVERAL DAYS. LONGWAVE TROUGH REMAINS OVER THE EASTERN HALF OF THE CONTINENT... WITH A LONGWAVE RIDGE CENTERED ALONG THE WESTERN COAST. WE REMAIN IN PRIMARILY DRY AND COOL NORTHWEST UPPER FLOW. HOWEVER... SOME FLURRIES AND A FEW SNOW SHOWERS ARE EVIDENT IN RADAR IMAGERY AND SURFACE OBS GIVEN SOME WEAK FORCING FROM CHANNELED VORTICITY ADVECTION COMBINED WITH GOOD LAPSE RATES AND JUST ENOUGH MOISTURE TO GET THINGS GOING. THESE CONDITIONS WON/T CHANGE MUCH TODAY... SO THE EASTERN/NORTHERN PORTION OF THE AREA SHOULD CONTINUE TO SEE SOME FLURRIES AND THE ODD SNOW SHOWER THROUGH THE DAY... PERHAPS PICKING UP SOME DURING THE AFTERNOON AS LAPSE RATES STEEPEN IN THE BOUNDARY LAYER. MOSTLY CLOUDY CONDITIONS WILL PERSIST AS WELL... ALTHOUGH SOME BREAKS OF SUNSHINE WILL ONCE AGAIN OCCUR. THE FAR SOUTHWEST PORTION OF THE CWFA WILL HAVE A DEJA VU MOMENT... WITH A VERY SIMILAR SYSTEM TO YESTERDAY PASSING BY TO ITS WEST AND SOUTH THIS MORNING AND EARLY AFTERNOON. GIVEN WHERE THE PCPN IS ALREADY TRYING TO DEVELOP OVER THE DAKOTAS... ITS TRAJECTORY LOOKS TO ONCE AGAIN LARGELY MISS OUR FORECAST AREA... ALTHOUGH SOME FLURRIES OR BRIEF LIGHT SNOW COULD SNEAK ACROSS LOCATIONS SOUTHWEST OF THE MINNESOTA VALLEY. THE HRRR... HOPWRF... AND MPXWRF ALL TELL SIMILAR TALES WITH THIS AREA OF PCPN... KEEPING ANYTHING MEANINGFUL OUT OF OUR AREA. KEPT SOME LOW POPS FOR LIGHT SNOW IN THE FAR SOUTHWEST... WITH A MENTION OF FLURRIES BORDERING ITS NORTHEAST EDGE UP TOWARD THE MINNESOTA RIVER. SOME SURFACE RIDGING LOOKS LIKE IT WILL TRY TO BUILD INTO THE AREA TONIGHT... SO ALLOWED THE ISOLATED SNOW SHOWERS OVER THE NORTHEAST FORECAST AREA TO WIND DOWN IN THE EARLY EVENING. HOWEVER... WITH THE MID-LEVEL COLD POOL STILL OVER THE AREA AND SOME CONTINUED WEAK FORCING... WOULDN/T RULE OUT THE NEED FOR LATER FORECASTS TO THROW A MENTION OF SNOW SHOWERS/FLURRIES BACK INTO THE FORECAST FOR THE ENTIRE NIGHT. REGARDLESS... ANYTHING THAT OCCURS SHOULDN/T BE OF MUCH SIGNIFICANT... WITH ONLY THE HEAVIEST OF SNOW SHOWERS PERHAPS WHITENING THE GROUND. .LONG TERM...(THURSDAY THROUGH TUESDAY) ISSUED AT 255 AM CDT WED OCT 23 2013 THE WESTERN PERIPHERY OF THE EASTERN CONUS MID/UPPER TROUGH HAS ONE LAST DAY OF INFLUENCE OVER THE LOCAL WEATHER ON THURSDAY...WITH STEEPENING LAPSE RATES INDICATING THE POTENTIAL FOR A FEW LIGHT SHOWERS/SPRINKLES...POSSIBLY IN THE FROZEN FORM FOR AREAS NORTH OF INTERSTATE 94 DURING THE MORNING. TEMPS WILL STILL BE ON THE CHILLY SIDE...WITH HIGHS IN THE UPPER 30S TO LOWER 40S EXPECTED...AND LOWS DIPPING INTO THE MID AND UPPER 20S BY DAYBREAK FRIDAY. FRIDAY APPEARS DRY AND A TAD WARMER...AS SOUTHWEST LLVL FLOW DEVELOPS AHEAD OF THE NEXT NORTHERN STREAM WAVE. THE ASSOCIATED TROUGH PASSES ON FRIDAY NIGHT...WITH THE MAIN RESULT BEING A SHIFT TO BRISK NORTHWEST WINDS FOR SATURDAY. WITH THE PRIMARY FORCING RELATED TO THE WAVE PASSING OVER THE GREAT LAKES REGION...NO PRECIPITATION IS EXPECTED FOR THE MAJORITY OF THE AREA...ALTHOUGH A FEW FLURRIES OR LIGHT SNOW/RAIN SHOWERS APPEAR POSSIBLE OVER WEST CENTRAL WI ON FRIDAY NIGHT AND SATURDAY. TEMPERATURES RECOVER A BIT FOR SUNDAY...ALTHOUGH ONLY AREAS ALONG/SOUTH OF THE MN RIVER VALLEY ARE EXPECTED TO ESCAPE THE 40S. DURING THE BEGINNING OF NEXT WEEK...AN UPPER TROUGH IS CARVED OUT FROM THE FOUR CORNERS REGION ACROSS THE CENTRAL/NORTHERN PLAINS. WHILE THERE ARE SOME AMPLITUDE DIFFERENCES BETWEEN THE GFS AND ECMWF...BOTH MODELS INDICATE AT LEAST A SLIGHT POTENTIAL FOR SHOWERS IN THE MONDAY-TUESDAY TIME FRAME. HAVE INCLUDED 20-30 POPS FOR BOTH DAYS. THE PRECIP TYPE WILL BE UNCERTAIN UNTIL THE OTHER LARGER DETAILS ARE WORKED OUT...ALTHOUGH THERMAL PROFILES ARE SUPPORTIVE OF RAIN-SNOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON) ISSUED AT 1225 PM CDT WED OCT 23 2013 PERSISTENT COLD NW FLOW ALOFT WITH MODEST MOISTURE AND OCCASIONAL WEAK SHTWVS DIVING DOWN WITHIN THE FLOW WILL KEEP BKN/OVC MIDLVL CEILINGS IN PLACE WITH LITTLE-TO-NO CLOUDS SUB-3000FT. ASIDE FROM SOME PATCHES OF -SN SHIFTING SE THRU FAR ERN MN AND WRN WI...TAF SITES WILL REMAIN VFR WITH CEILINGS IN THE 3500-5000 FT RANGE THRU TMRW. FOR MAINLY KRNH AND POSSIBLY KEAU...PATCHY SNOWFALL MAY DRIVE OVER THE TERMINALS AND PRODUCE IFR-LEVEL VSBY ALONG WITH LOWER CLOUD CEILINGS BUT THIS WOULD BE SHORT-LIVED AND FOR MAINLY THIS AFTN INTO THIS EVE. FOR TNGT INTO TMRW...MAINLY PRECIP-FREE CONDS ARE EXPECTED BUT THE CEILINGS WILL LIKELY REMAIN. WINDS WILL REMAIN PRIMARILY NW WITH SPEEDS ARND 10 KT...THOUGH SPEEDS MAY CLIMB TO THE 14G20KT AREA THIS AFTN BEFORE SETTLING DOWN THIS EVE. KMSP...VFR CONDS EXPECTED THROUGHOUT THIS TAF SET. CEILINGS IN THE 3500-5000 FT RANGE EXPECTED...THOUGH THERE MAY OCCASIONALLY BE FEW-SCT 2000-2500 FT CLOUDS THAT SKIP THROUGH THE AREA. AM NOT LOOKING FOR CEILINGS AT THOSE LEVELS...AND CERTAINLY NOT AS LOW AS 1700 FT. CEILINGS WILL GRADUALLY RISE OVERNIGHT THRU TMRW. NOT LOOKING FOR PRECIP BUT THERE STILL MAY BE AN OCCASIONAL FLURRY OR SNOW SHOWER THAT DRIFTS OVER THE TERMINAL SO WILL CONTINUE TO MONITOR AND AMEND IF NEEDED. WINDS NW IN THE 5-12 KT RANGE THROUGHOUT. /OUTLOOK FOR KMSP/ THU NIGHT...VFR. W WIND 5-10 KT. FRI...VFR. SW WIND 10-20 KT INCRG TO 15-25 KT. FRI NIGHT...MVFR CIGS PSBL LATE. SW WIND 15-25 KT BECMG W. SAT...MVFR CIGS PSBL. NW WIND 10-20 KT. SAT NIGHT...VFR. NW WIND 5-15 KT BECMG VRBL LESS THAN 10 KT. SUN...VFR. S WIND 5 TO 15 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM... LONG TERM...LS AVIATION...JPC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1211 PM CDT WED OCT 23 2013 .UPDATE... A FEW MORNING UPDATES TO REFINE POPS/RAIN/SNOW MENTION ALONG WITH TEMPERATURES AND WINDS. && TEMPERATURES JUST COLD ENOUGH TO HAVE A BAND OF A MIX WITH SLEET AND WET SNOWFLAKES MIXED IN. WSR-88D REFLECTIVITY HIGHLIGHTED THIS AS WELL AS THE DUAL-POL CC (ZDR/KDP) PRODUCTS. SNOW WAS REPORTED AT ARLINGTON...FORT CALHOUN...AND BENNINGTON EARLIER THIS MORNING. THIS AREA IS SLOWLY SHIFTING EASTWARD IN RESPONSE TO THE UPPER LEVEL SHORTWAVE AND WILL CONTINUE TO DO SO DURING THE AFTERNOON THUS THE GRADIENT IN POPS...HIGHEST IN WESTERN IOWA. TEMPERATURES WILL ALSO VARY FROM SOUTHWEST TO NORTHEAST WITH UPPER 50S IN THE SOUTHWEST TOWARD FAIRBURY TO THE 40S IN WESTERN IOWA. && .AVIATION... 18Z TAFS FOR KOMA...KOFK...KLNK BAND OF RAIN/SNOW MIX HAS LIFTED NORTHEAST OF THE TAF SITES AND THE PRECIP AREA SHOULD REMAIN MAINLY TO THE NORTHEAST THROUGH THE AFTERNOON. DO HAVE VFR CIGS MENTIONED FL050-100 WITH DECREASING CLOUDS TONIGHT. SURFACE WINDS FROM THE SOUTH TO SOUTHWEST WINDS VEER WITH TIME BECOMING NORTHERLY DURING THE AFTERNOON. MOST WINDS WILL BE IN THE 6 TO 12KT RANGE ALTHOUGH SOME BRIEFLY STRONGER WINDS ARE POSSIBLE. TONIGHT THE WINDS SHOULD DROP BELOW 8KTS. .PREV DISCUSSION... /ISSUED 245 AM CDT WED OCT 23 2013/ DISCUSSION... SKIES HAD CLEARED ACROSS MUCH OF EASTERN NEBRASKA AND SOUTHWEST IOWA SINCE 05Z BUT ADDITIONAL CLOUDS OVER THE DAKOTAS ARE EXPECTED TO SPREAD INTO THE AREA PRIOR TO SUNRISE. RADAR ALSO PICKING UP SOME LIGHT PRECIP OVER NORTH CENTRAL SOUTH DAKOTA WITH SHORT RANGE MODELS BRINGING THE PRECIP INTO THE AREA DURING THE MORNING. AS THE CLOUD COVER RETURNS TO BLANKET THE AREA THIS MORNING WE SHOULD SEE TEMPERATURES WARM. RAP FORECAST SOUNDINGS SHOW RAIN TO BE PRIMARY PRECIP TYPE...ALTHOUGH A MIX IS POSSIBLE NORTH OF OMAHA IF ACTUAL TIMING IS FASTER THAN EXPECTED. PERIODS OF SHOWERS THEN EXPECTED THROUGH THE DAY OVER EASTERN PARTS OF THE AREA BUT ENDING NORTH TO SOUTH DURING THE AFTERNOON. REMAINDER OF THE SHORT TERM LOOKS DRY BUT COLD FOR TONIGHT WITH A HARD FREEZE LIKELY ACROSS NORTHERN PARTS OF THE AREA. LIGHT WINDS ON THURSDAY WITH HIGH PRESSURE OVER THE AREA EXPECTED TO HOLD TEMPERATURES IN THE 40S BUT WARMER TEMPERATURES RETURN FRIDAY INTO THE WEEKEND. EXTENDED PERIOD EARLY NEXT WEEK STILL PROBLEMATIC AS OPERATIONAL MODELS DIFFER IN HANDLING OF ENERGY COMING INTO THE GREAT BASIN ON MONDAY AND EVOLUTION OF THE SYSTEM AS IT TRACKS EAST TOWARD THE SOUTHERN PLAINS TUESDAY AND WEDNESDAY. HAVE MAINTAINED CURRENT TRENDS IN THE FORECAST BUT HIGHS ON MONDAY UNCERTAIN DUE TO TIMING AND STRENGTH OF THE FRONT BY THE GFS AND ECMWF. FOBERT && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1239 PM EDT WED OCT 23 2013 .SYNOPSIS... A WEAK ALBERTA CLIPPER STORM SYSTEM WILL MOVE EAST ACROSS THE REGION TODAY. A COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA BY THURSDAY MORNING AND BECOME NEARLY STATIONARY OVER THE LOCAL AREA. HIGH PRESSURE WILL MOVE EAST INTO THE OHIO AND TENNESSEE VALLEYS AT THE SAME TIME. THE HIGH WILL EVENTUALLY DISSIPATE BY THURSDAY NIGHT AS ANOTHER HIGH BUILDS SOUTHEAST INTO THE OHIO VALLEY BY FRIDAY MORNING. YET ANOTHER COLD FRONT WILL SLIDE SOUTHEAST ACROSS THE AREA ON FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... NOT MANY CHANGES FOR THE MIDDAY UPDATE. TEMPERATURES WERE SLOW TO WARM THIS MORNING DUE TO CLOUD COVER AND PRECIP BUT ARE NOW STARTING TO WARM MORE RAPIDLY. LOWERED HIGH TEMPERATURES A COUPLE OF DEGREES ACROSS THE SOUTHEASTERN PORTION OF THE FORECAST AREA DUE TO THE LINGERING BAND OF PRECIP. THERE WERE A COUPLE OF REPORTS OF SNOW/MIXED PRECIP FROM THIS MORNING...MAINLY FROM AREAS OF HIGHER ELEVATION. BY NOW ALL PRECIP HAS TRANSITIONED TO RAIN. PREVIOUS DISCUSSION...A WEAK TROUGH REMAINS PERSISTENT FROM SOUTHWEST TO NORTHEAST OVER THE LAKE RESULTING IN A BAND OF SHOWERS THAT CONTINUES TO DEVELOP ALONG THE LAKE SHORE OF NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA. THIS AREA OF PRECIPITATION IS THE RESULT OF CONSIDERABLE CONVERGENCE ALONG THE SHORE LINE. TEMPERATURES CONTINUE TO HOVER IN THE UPPER 30S TO NEAR 40 DEGREES NEAR THE LAKE AND IN THE MIDDLE 30S ELSEWHERE. SO FAR...NO REPORTS OF SNOW IN THE FORECAST AREA AT THIS TIME. SOME LIGHT SNOW WAS REPORTED AT MARION EARLIER THIS MORNING. OVERALL TREND SHOULD CONTINUE THROUGH THE DAY AS THE CLIPPER LOW PRESSURE SYSTEM SLIDES GRADUALLY EAST ACROSS OHIO INTO PENNSYLVANIA. BULK OF PRECIPITATION STILL REMAINING SOUTH OF THE AREA WHERE THE BEST DYNAMICS IS LOCATED. TEMPERATURES SHOULD REBOUND VERY SLOWLY INTO THE MIDDLE AND UPPER 40S. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... ANOTHER SHOT OF COLDER AIR WILL ARRIVE TOWARD MORNING AND I ANTICIPATE WITH 1000 TO 500 MB THICKNESS VALUES DIPPING TO AROUND 525 OR SO OVERNIGHT...WE WILL LIKELY SEE ENOUGH COLD AIR TO SUPPORT THE FINAL KILLING FREEZE OF THE SEASON FOR ALL AREAS EXCEPT EXTREME NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA. WILL GO AHEAD AND ISSUE A FREEZE WATCH FOR TONIGHT. LAKE EFFECT PRECIPITATION AND CLOUDS ALONG WITH WARM INFLUENCE OF THE LAKE SHOULD KEEP TEMPERATURES FROM DIPPING TOO FAR BELOW 33 DEGREES AND WILL HOLD OFF ON A WATCH IN THAT AREA. TEMPERATURES SHOULD WARM UP TO SIMILAR TO WHAT WE WILL SEE TODAY FOR HIGHS ON THURSDAY IN THE MIDDLE 40S. I AM WORRIED THIS MAY BE A BIT TOO WARM DUE TO THE COLD AIR ADVECTION BEHIND THE FRONT EXPECTED. A SHOT OF POSITIVE VORTICITY ADVECTION AND ASSOCIATED MOISTURE WILL ROTATE DOWN ACROSS THE EASTERN HALF OF THE FORECAST AREA ON THURSDAY AND CONVERGENCE COULD POSSIBLY DEVELOP ALONG THE NORTHEAST LAKE SHORE TO PRODUCE A MIX OF SNOW AND RAIN IN THE LAKE EFFECT AREAS. THE REST OF THE FORECAST AREA MAY SEE SOME SPRINKLES BUT WILL LEAVE IT DRY FOR NOW AS MOISTURE IN THIS AREA HOLDS OFF UNTIL EVENING. THURSDAY NIGHT INTO FRIDAY WILL STILL SEE THE EFFECTS OF THE UPPER LEVEL VORTICITY MAXIMUM OVER THE EASTERN HALF OF THE FORECAST AREA. REST OF THE AREA SHOULD REMAIN DRY AT THIS TIME. TEMPERATURE PROFILES SUPPORT A MIX OF RAIN AND SNOW IN THE NORTHEAST THURSDAY NIGHT AND MAINLY RAIN FRIDAY AFTERNOON. THE PRECIPITATION WILL BEGIN TO RETREAT FRIDAY NIGHT FOR A BRIEF PERIOD AS HIGH PRESSURE BRINGS A BRIEF PERIOD OF FAIR WEATHER TO THE FORECAST AREA FRIDAY NIGHT. BUT COLD FRONT WILL SWEEP THROUGH SATURDAY WITH ITS ASSOCIATED MOISTURE AND BRINGS WITH IT A CHANCE FOR MORE SHOWERS. COLD AIR ADVECTION IS NOT EXPECTED TO BE REAL STRONG SO OVERNIGHT LOWS AND DAY TIME HIGHS HOLDING STEADY. && .LONG TERM /SUNDAY THROUGH TUESDAY/... PREVIOUS FORECAST HAD A GOOD HANDLE ON THE BIG PICTURES SO HAVE ONLY MADE MINOR ADJUSTMENTS. HIGH PRESSURE WILL BEGIN TO BUILD OVER THE LOCAL AREA ON SUNDAY WITH JUST A FEW LINGERING SHOWERS POSSIBLE TO THE EAST OF KCLE. WESTERN AREAS SHOULD BE DRY WITH SOME SUNSHINE LIKELY. MONDAY WILL ALSO BE DRY WITH LOT`S OF SUNSHINE AND HIGHS FINALLY RETURNING TO NEAR NORMAL. A STRONG SYSTEM WILL IMPACT THE REGION AT THE END OF THE PERIOD. SHOWERS WILL ARRIVE IN THE WEST LATE MONDAY NIGHT AND SHOULD SPREAD ACROSS THE REMAINDER OF THE AREA ON TUESDAY. SUSPECT THAT WE WILL EVENTUALLY NEED HIGH POPS FOR TUESDAY AND HAVE TRENDED CHANCES UP A LITTLE THIS MORNING. && .AVIATION /12Z WEDNESDAY THROUGH MONDAY/... A BAND OF SHOWERS HAS BEGUN TO SAG SOUTH OFF OF LAKE ERIE. THIS BAND WILL AFFECT KCLE WITHIN THE HOUR AND AT KYNG IN AN HOUR OR TWO. MOST LOCATIONS REMAIN VFR BUT PERIODS OF MVFR CIGS AND VSBYS WITH THE HEAVIER RAINS. SOME IFR CIGS ARE ALSO BEING REPORTED AT THE SOUTHERN END OF THE AREA. LATEST HRRR MODELS SHOWS SHOWERS ALONG AND EAST OF THE I-71 CORRIDOR. MOST OF THIS ACTIVITY SHOULD BE GONE BY 18Z. SOME SHOWERS WILL LIKELY DEVELOP AND MOVE OFF OF LAKE ERIE LATER THIS AFTERNOON. DRIER AIR SHOULD BEGIN TO WIN OUT TONIGHT AND EXPECT MAINLY VFR CONDITIONS BY 00Z. WESTERLY FLOW WILL BECOME NW TONIGHT AND INCREASE SOME. GUSTS TO 20 KNOTS ARE POSSIBLE THIS AFTERNOON. OUTLOOK...NON-VFR POSSIBLE THROUGH FRIDAY IN RAIN AND SNOW SHOWERS. && .MARINE... WEST TO NORTHWEST FLOW IS EXPECTED ON THE LAKE TODAY WITH SPEEDS INCREASING AFTER DAYBREAK. NORTHWEST FLOW WILL CONTINUE THROUGH FRIDAY AS HIGH PRESSURE PASSES TO THE SOUTH. HAVE EXTENDED THE SMALL CRAFT THROUGH THURSDAY NIGHT AND EXPECT THAT IT WILL EVENTUALLY BE NEEDED FRIDAY AS WELL. SW FLOW WILL FINALLY RETURN TO THE LAKE ON SATURDAY BUT YET ANOTHER COLD FRONT WILL ARRIVE LATE IN THE DAY. THIS WILL CAUSE THE FLOW TO RETURN TO THE NORTHWEST. MORE HEADLINES WILL LIKELY BE NEEDED AS THIS OCCURS. ANOTHER RIDGE WILL MOVE ACROSS THE LAKE ON SUNDAY ENDING THE THREAT FOR PRECIP AND CAUSING THE FLOW TO RETURN TO THE SW BY THE END OF THE PERIOD. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FREEZE WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR OHZ003-006>010-017>023-027>033-036>038-047. PA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR LEZ145>149. SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LEZ142>144. && $$ SYNOPSIS...LOMBARDY NEAR TERM...LOMBARDY/SCHEPEL SHORT TERM...LOMBARDY LONG TERM...KUBINA AVIATION...KUBINA MARINE...KUBINA
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND THURSDAY ISSUED AT 246 PM CDT WED OCT 23 2013 LATEST RADAR/SATELLITE IMAGERY AND RUC ANALYSIS SHOW A DEEP TROUGH POSITIONED OVER THE NORTHEAST HALF OF THE UNITED STATES. AMPLE CLOUD COVER IS ROTATING THROUGH AND AROUND THIS TROUGH WITH SOME DIURNAL ENHANCEMENT LEADING TO INSTABILITY SNOW AND RAIN SHOWERS ACROSS THE STATE. MOST OF THE PRECIP HAS REMAINED OVER CENTRAL AND NORTH-CENTRAL WISCONSIN...BUT THINK SOME SHOWERS REACH INTO THE FOX VALLEY AND DOOR COUNTY LATER THIS AFTERNOON. BEING DIURNALLY ENHANCED...SHOWERS AWAY FROM THE SNOW BELTS SHOULD THEN DIMINISH EARLY THIS EVENING. DUE TO NORTHWEST FLOW PERSISTING...LAKE EFFECT SNOW SHOWERS AND ACCUMULATION POSSIBILITIES ARE THE MAIN FORECAST CONCERNS. TONIGHT...VERY LITTLE CHANGES TONIGHT COMPARED TO THE PAST COUPLE NIGHTS. COLD CYCLONIC FLOW WILL REMAIN PRESENT THROUGH THE COLUMN WITH PLENTY OF STRATUS UPSTREAM WHICH WILL LEAD TO A BROKEN CLOUD DECK. 1000-850MB WINDS DO VEER TO A 330 DIRECTION OVER LAKE SUPERIOR BY MID TO LATE EVENING...WHICH IS FAVORABLE FOR LAKE EFFECT PRECIP OVER NORTH-CENTRAL WISCONSIN. COMBINED WITH DELTA T/S AROUND 18C AND AMPLE MOISTURE IN THE 850-700MB LAYER...SHOULD SEE ACCUMULATING SNOW SHOWERS WITHIN THE SNOW BELTS. PROGGED SOUNDINGS SHOW THE SATURATED LEVEL BARELY REACHING THE DENDRITIC GROWTH ZONE...SO SNOW RATIOS SHOULD REMAIN RELATIVELY LOW COMPARED TO WHAT THEY TYPICALLY ARE IN A LAKE EFFECT SCENARIO. ACCUMULATIONS TWO NIGHTS AGO MAXED OUT IN THE 2-3 INCH RANGE OVER NORTHERN VILAS COUNTY...SO THATS ABOUT WHAT IM EXPECTING TONIGHT. WIND SPEEDS ARE ONLY AROUND 15 KNOTS...SO LOCATIONS OVER THE SOUTHERN HALF OF THE COUNTY MAY ONLY SEE AN INCH OR LESS. LOWS FIRMLY IN THE 20S. THURSDAY...LAKE EFFECT SNOW SHOWERS WILL BE ONGOING OVER NORTH-CENTRAL WISCONSIN...BUT SHOULD BE GRADUALLY WINDING DOWN OVER THE COURSE OF THE MORNING AS WINDS BACK AROUND AGAIN. WILL SHOW ANOTHER HALF INCH TO AN INCH IN THE FORECAST. ELSEWHERE...ANOTHER DAY LIKE TODAY...WITH PARTLY TO MOSTLY CLOUDY SKIES AND ISOLATED TO SCATTERED FLURRIES AND SPRINKLES. LOW LEVEL TEMPS ARE A DEGREE OR SO COLDER THAN TODAY SO WILL DROP MAX TEMPS APPROPRIATELY. HIGHS IN THE MID 30S NORTHWEST TO MID 40S SOUTHEAST. .LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY ISSUED AT 246 PM CDT WED OCT 23 2013 LAKE EFFECT SNOW SHOWERS SHOULD CONTINUE FOR AWHILE THURSDAY NIGHT IN VILAS COUNTY UNTIL WIND FIELD WEAKENS AND BECOMES MORE WESTERLY AND LOSES FETCH. EXPECT ACCUMULATIONS TO BE LESS THAN AN INCH. BREEZY AND SLIGHTLY WARMER FRIDAY IN WARM ADVECTION AHEAD OF THE NEXT COLD FRONT. MODELS HAVE A STRONG LOW LEVEL JET ACROSS NORTHEAST WISCONSIN FRIDAY NIGHT BUT DRY AIR WILL HINDER PRECIPITATION PRODUCTION. KEPT A CHANCE OF RAIN OR SNOW IN THE NORTHEAST PART OF THE FORECAST AREA. A COLD FRONT MOVES THROUGH SATURDAY MORNING WITH GUSTY WINDS POSSIBLE AS COLD AIR DEEPENS DURING THE DAY. LAKE EFFECT SNOW POTENTIAL WILL INCREASE IN NORTHCENTRAL WISCONSIN SATURDAY AFTERNOON AND EVENING AS THE AIR BECOMES MORE UNSTABLE. A COUPLE OF INCHES LOOK LIKELY AT THIS POINT. DRY WEATHER EXPECTED SUNDAY AS SURFACE HIGH BUILDS IN. THEN MODELS DIFFER ON WHAT HAPPENS MONDAY AND TUESDAY AS UPPER FLOW SPLITS AND A INVERTED TROUGH SETS UP TO OUR SOUTHWEST. LOOKS LIKE THE BEST PRECIPITATION WILL STAY TO OUR SOUTH THROUGH MIDWEEK. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1232 PM CDT WED OCT 23 2013 NO CHANGE IN THE WEATHER PATTERN OVER THE NEXT 24 HOURS AS NORTHWEST FLOW WILL REMAIN IN PLACE. SCT SNOW SHOWERS AND FLURRIES WILL CONTINUE TO IMPACT CENTRAL AND NORTH-CENTRAL WISCONSIN THIS AFTERNOON. SOME SPOTTY MVFR CIGS OUT THAT WAY AS WELL AND THINK THEY COULD PERSIST THROUGH EARLY AFTERNOON. THEN ANTICIPATING VFR CONDITIONS WITH VARIABLE CIGS THROUGH EARLY THIS EVENING. WIND TRAJECTORIES WILL BECOME MORE FAVORABLE FOR ACCUMULATING LAKE EFFECT SNOW SHOWERS OVER NORTH-CENTRAL WISCONSIN TONIGHT. A COUPLE INCHES OF ACCUMULATION LOOK POSSIBLE. THE LATEST GUIDANCE ALSO SHOWS CIGS FALLING LATE TONIGHT BACK TO MVFR OR IFR OVER NORTHERN WISCONSIN AS WELL. CONFIDENCE IS LOW THAT THESE LOWER CIGS WILL IMPACT OTHER AREAS SO WILL LEAVE CONDITIONS AS VFR OR HIGH END MVFR ELSEWHERE THROUGH THE REST OF THE TAF PERIOD. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......RDM AVIATION.......MPC