Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/22/13


AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
234 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 00Z TAFS THROUGH 00Z MONDAY EVENING) ISSUED AT 233 PM MDT SUN OCT 20 2013 EXPECT AREAS OF MOUNTAIN OBSCURATION OVER THE ELKHEAD...PARK...GORE...AND PORTIONS OF THE ELK RANGES THIS AFTERNOON. THERE IS A SLIGHT CHANCE THAT KCAG...KEEO... KHDN...KSBS...AND KEGE WILL EXPERIENCE BRIEF MVFR CIGS IN LIGHT SHOWERS THROUGH 03Z THEN VFR CONDITIONS WILL DOMINATE. ELSEWHERE...EXPECT VFR CONDITIONS TO PERSIST THROUGH THE NEXT 24 HOURS AND BEYOND. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...JOE LONG TERM...JAD AVIATION...JOE
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1111 AM MDT SUN OCT 20 2013 .UPDATE... ISSUED AT 1110 AM MDT SUN OCT 20 2013 SNOW SHOWERS HAVE WORKED INTO NW COLORADO THIS EARLY MORNING. SPOTTERS BETWEEN STEAMBOAT SPRINGS AND CLARK REPORT SNOW FLURRIES. SNOTEL SITES HAVE NOT RESPONDED YET AND ARE HOVERING NEAR 32 DEGREES. THE MORNING MODELS ARE CONSISTENT WITH PREVIOUS RUNS PRODUCING 1-3 INCHES IN THE ELKHEAD AND ZIRKEL MOUNTAINS WITH LESS INTO THE PARK AND FLATTOPS MOUNTAINS...WITH SOME LIGHT SNOW INTO THE ELK MTNS THROUGH THE AFTERNOON INCLUDING INDEPENDENCE AND COTTONWOOD PASSES. CRAIG MAY SEE A FLURRY...AND PUT A SLIGHT CHANCE OF SHOWERS IN THE I-70 CORRIDOR EAST OF GLENWOOD SPRINGS. THE BEST FORCING PASSES OVER THE ELKHEADS THIS AFTERNOON BUT COLD ADVECTIVE NW FLOW MAY PRODUCE LIGHT SNOW ACROSS THE MENTIONED NORTHERN CO MTNS THROUGH THE EVENING HOURS WHEN THE -22C COLD CORE PASSES. SOME CLOUDS WILL LINGER OVERNIGHT IN NW CO... OTHERWISE CLEARING SKIES WILL KEEP TEMPERATURES BELOW NORMAL TONIGHT AND MONDAY. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 331 AM MDT SUN OCT 20 2013 A FAST MOVING SHORTWAVE IN THE NORTHWESTERLIES WILL IMPACT THE NORTHERN AND PORTIONS OF THE CENTRAL MOUNTAINS TODAY. HIGH CLOUDS AHEAD OF THE SYSTEM BEGAN SWEEPING OVER THE NORTH LAST EVENING. EXPECT SHOWERS WILL HOLD OFF UNTIL AFTER 12Z PER CONSENSUS OF GFS40...NAM12...RAP13...AND HRRR MODELS. THEREFORE ...PARED BACK POPS EARLY THIS MORNING. AS THE SHORTWAVE SWEEPS SOUTHEASTWARD ACROSS SOUTHWEST WYOMING SHOWERS WILL DEVELOP OVER THE ELKHEADS AROUND SUNRISE. THIS ACTIVITY WILL SPREAD TO THE PARK AND GORE RANGES...FLAT TOPS...AND ELK MOUNTAINS AS THE AXIS OF THE SHORTWAVE SWEEPS INTO NORTHWEST COLORADO THIS AFTERNOON. UPWARD FORCING...OROGRAPHIC LIFT AND SUFFICIENTLY STEEP LAPSE RATES WILL BRING ACCUMULATING SNOW TO THE NORTHERN AND CENTRAL MOUNTAINS. SNOW LEVELS WILL SETTLE AROUND MOUNTAIN BASES IN THE NORTH AND NEAR 8500 FEET IN THE CENTRAL MOUNTAINS THIS AFTERNOON. MOISTURE LACKING WITH THIS SYSTEM SO WILL CONTINUE WITH 1 TO 2 INCH ACCUMULATIONS IN THE MOUNTAIN AREAS MENTIONED PREVIOUSLY. LOWER ELEVATIONS EAST OF KCAG-KASE LINE COULD SEE BRIEF SHOWERS BUT CHANCES NOT GREAT GIVEN LIMITED MOISTURE. ELSEWHERE...EXPECT DRY WEATHER TO CONTINUE WITH PARTLY SUNNY TO MOSTLY SUNNY SKIES AND HIGHS CONTINUING TO RUN A BIT COOL FOR THIS TIME OF YEAR. A PUSH OF COOLER AIR COMBINED WITH CLOUDS AND SHOWERS WILL DECREASE TEMPERATURES AROUND 5 DEGREES ACROSS NORTH- CENTRAL COLORADO THIS AFTERNOON. SNOW GRADUALLY TAPERS OFF OVERNIGHT FROM THE NORTH AS THE BULK OF PRECIPITATION HANGS OVER THE DIVIDE THROUGH THE MORNING HOURS MONDAY WITH FAVORABLE WIND DIRECTION FOR LINGERING LIGHT SNOW STRETCHING ALONG THE CENTRAL MOUNTAIN CORRIDOR. SNOW LEVEL WILL DECREASE TO AROUND 6500 FEET BY EARLY MONDAY MORNING WITH THE ADVECTION OF COLD NORTHERLY AIR. 1 TO 3 INCHES OF SNOW IS EXPECTED OVER THE NORTHERN MOUNTAINS AND PORTIONS OF THE CENTRAL MOUNTAINS THROUGH EARLY MONDAY MORNING...WITH THE POTENTIAL FOR LOCALLY HIGHER AMOUNTS. THE SHORTWAVE IS FORECAST TO PROGRESS TO THE VERY EASTERN PART OF CENTRAL COLORADO BY NOON MONDAY...SO ALL PRECIPITATION IS EXPECTED TO HAVE CEASED OVER THE DIVIDE WITH BRISK NORTHERLY AIR FILTERING IN BEHIND IN AN AREA OF SUBSIDENCE. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 331 AM MDT SUN OCT 20 2013 CLEAR SKIES AND SLIGHTLY BELOW NORMAL TEMPERATURES WILL REIGN AS HIGH PRESSURE BUILDS INTO THE REGION MONDAY NIGHT. WINDS WILL REMAIN LIGHT...ALLOWING INVERSIONS TO DEVELOP IN VALLEY BOTTOMS OVERNIGHT AND KEEP LOW TEMPERATURES BELOW NORMAL. A WEAK MID-LEVEL LOW PRESSURE TROUGH OVER THE WEST COAST UNDERCUTS THE RIDGE...MOVING EASTWARD ACROSS THE GREAT BASIN AND DESERT SOUTHWEST TUESDAY NIGHT THROUGH THURSDAY. MODELS TAKE THE BULK OF THE ENERGY ASSOCIATED WITH THIS FEATURE SOUTH OF THE FORECAST AREA FROM THURSDAY NIGHT INTO FRIDAY BEFORE PUSHING IT ONTO THE SOUTHERN PLAINS SATURDAY. LATEST ECMWF FARTHER SOUTH WITH THIS FEATURE THAN YESTERDAY/S 00Z RUN WHICH LIMITS CHANCES FOR ANY SENSIBLE WEATHER OVER THE SAN JUANS FRIDAY. LESS ENERGETIC GFS SHOWED LITTLE CHANGE AND ALSO DRY FRIDAY. AS A RESULT...KEPT MENTION OF PRECIPITATION CHANCES OUT OF THE FORECAST THROUGHOUT THE ENTIRE EXTENDED PERIOD. EXPECT TEMPERATURES WILL HOVER NEAR NORMAL THROUGH THE COMING WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY MORNING) ISSUED AT 1110 AM MDT SUN OCT 20 2013 IN NW FLOW ALOFT A WEAK PASSING DISTURBANCE WILL BRUSH NORTH- CENTRAL COLORADO THROUGH THIS AFTERNOON AND THIS EVENING. SNOW HAS DEVELOPED EAST OF A LINE FROM KCAG SE TO KASE AND WILL INCREASE IN INTENSITY THIS AFTERNOON. EXPECT AREAS OF MOUNTAIN OBSCURATION OVER THE ELKHEAD...PARK...GORE...AND PORTIONS OF THE ELK RANGES THIS AFTERNOON. THERE IS A SLIGHT CHANCE THAT KCAG...KEEO... KHDN...KSBS...AND KEGE WILL EXPERIENCE BRIEF MVFR CIGS IN LIGHT SHOWERS THROUGH 06Z. ELSEWHERE...EXPECT VFR CONDITIONS TO PERSIST THROUGH THE NEXT 24 HOURS AND BEYOND. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ UPDATE...JOE SHORT TERM...NL/JAM LONG TERM...JAM/NL AVIATION...NL
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
331 AM MDT SUN OCT 20 2013 .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 331 AM MDT SUN OCT 20 2013 A FAST MOVING SHORTWAVE IN THE NORTHWESTERLIES WILL IMPACT THE NORTHERN AND PORTIONS OF THE CENTRAL MOUNTAINS TODAY. HIGH CLOUDS AHEAD OF THE SYSTEM BEGAN SWEEPING OVER THE NORTH LAST EVENING. EXPECT SHOWERS WILL HOLD OFF UNTIL AFTER 12Z PER CONSENSUS OF GFS40...NAM12...RAP13...AND HRRR MODELS. THEREFORE ...PARED BACK POPS EARLY THIS MORNING. AS THE SHORTWAVE SWEEPS SOUTHEASTWARD ACROSS SOUTHWEST WYOMING SHOWERS WILL DEVELOP OVER THE ELKHEADS AROUND SUNRISE. THIS ACTIVITY WILL SPREAD TO THE PARK AND GORE RANGES...FLAT TOPS...AND ELK MOUNTAINS AS THE AXIS OF THE SHORTWAVE SWEEPS INTO NORTHWEST COLORADO THIS AFTERNOON. UPWARD FORCING...OROGRAPHIC LIFT AND SUFFICIENTLY STEEP LAPSE RATES WILL BRING ACCUMULATING SNOW TO THE NORTHERN AND CENTRAL MOUNTAINS. SNOW LEVELS WILL SETTLE AROUND MOUNTAIN BASES IN THE NORTH AND NEAR 8500 FEET IN THE CENTRAL MOUNTAINS THIS AFTERNOON. MOISTURE LACKING WITH THIS SYSTEM SO WILL CONTINUE WITH 1 TO 2 INCH ACCUMULATIONS IN THE MOUNTAIN AREAS MENTIONED PREVIOUSLY. LOWER ELEVATIONS EAST OF KCAG-KASE LINE COULD SEE BRIEF SHOWERS BUT CHANCES NOT GREAT GIVEN LIMITED MOISTURE. ELSEWHERE...EXPECT DRY WEATHER TO CONTINUE WITH PARTLY SUNNY TO MOSTLY SUNNY SKIES AND HIGHS CONTINUING TO RUN A BIT COOL FOR THIS TIME OF YEAR. A PUSH OF COOLER AIR COMBINED WITH CLOUDS AND SHOWERS WILL DECREASE TEMPERATURES AROUND 5 DEGREES ACROSS NORTH- CENTRAL COLORADO THIS AFTERNOON. SNOW GRADUALLY TAPERS OFF OVERNIGHT FROM THE NORTH AS THE BULK OF PRECIPITATION HANGS OVER THE DIVIDE THROUGH THE MORNING HOURS MONDAY WITH FAVORABLE WIND DIRECTION FOR LINGERING LIGHT SNOW STRETCHING ALONG THE CENTRAL MOUNTAIN CORRIDOR. SNOW LEVEL WILL DECREASE TO AROUND 6500 FEET BY EARLY MONDAY MORNING WITH THE ADVECTION OF COLD NORTHERLY AIR. 1 TO 3 INCHES OF SNOW IS EXPECTED OVER THE NORTHERN MOUNTAINS AND PORTIONS OF THE CENTRAL MOUNTAINS THROUGH EARLY MONDAY MORNING...WITH THE POTENTIAL FOR LOCALLY HIGHER AMOUNTS. THE SHORTWAVE IS FORECAST TO PROGRESS TO THE VERY EASTERN PART OF CENTRAL COLORADO BY NOON MONDAY...SO ALL PRECIPITATION IS EXPECTED TO HAVE CEASED OVER THE DIVIDE WITH BRISK NORTHERLY AIR FILTERING IN BEHIND IN AN AREA OF SUBSIDENCE. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 331 AM MDT SUN OCT 20 2013 CLEAR SKIES AND SLIGHTLY BELOW NORMAL TEMPERATURES WILL REIGN AS HIGH PRESSURE BUILDS INTO THE REGION MONDAY NIGHT. WINDS WILL REMAIN LIGHT...ALLOWING INVERSIONS TO DEVELOP IN VALLEY BOTTOMS OVERNIGHT AND KEEP LOW TEMPERATURES BELOW NORMAL. A WEAK MID-LEVEL LOW PRESSURE TROUGH OVER THE WEST COAST UNDERCUTS THE RIDGE...MOVING EASTWARD ACROSS THE GREAT BASIN AND DESERT SOUTHWEST TUESDAY NIGHT THROUGH THURSDAY. MODELS TAKE THE BULK OF THE ENERGY ASSOCIATED WITH THIS FEATURE SOUTH OF THE FORECAST AREA FROM THURSDAY NIGHT INTO FRIDAY BEFORE PUSHING IT ONTO THE SOUTHERN PLAINS SATURDAY. LATEST ECMWF FARTHER SOUTH WITH THIS FEATURE THAN YESTERDAY/S 00Z RUN WHICH LIMITS CHANCES FOR ANY SENSIBLE WEATHER OVER THE SAN JUANS FRIDAY. LESS ENERGETIC GFS SHOWED LITTLE CHANGE AND ALSO DRY FRIDAY. AS A RESULT...KEPT MENTION OF PRECIPITATION CHANCES OUT OF THE FORECAST THROUGHOUT THE ENTIRE EXTENDED PERIOD. EXPECT TEMPERATURES WILL HOVER NEAR NORMAL THROUGH THE COMING WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 331 AM MDT SUN OCT 20 2013 A SOUTHEASTWARD PROPAGATING UPPER LEVEL DISTURBANCE WILL BRUSH NORTH-CENTRAL COLORADO TODAY. SNOW WILL DEVELOP OVER THE ELKHEAD MOUNTAINS THIS MORNING THEN SPREADS SOUTHEAST WHILE INCREASING IN INTENSITY THIS AFTERNOON. AS A RESULT...EXPECT AREAS OF MOUNTAIN OBSCURATION OVER THE ELKHEAD...PARK...AND PORTIONS OF THE PARK RANGE THIS MORNING...BECOMING WIDESPREAD THIS AFTERNOON. THERE IS A SLIGHT CHANCE THAT KCAG...KEEO...KHDN...KSBS...AND KEGE WILL EXPERIENCE BRIEF MVFR CIGS IN LIGHT SHOWERS FROM 18Z TO 00Z. ELSEWHERE...EXPECT VFR CONDITIONS TO PERSIST THROUGH THE NEXT 24 HOURS. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && $$ SHORT TERM...NL/JAM LONG TERM...JAM/NL AVIATION...NL
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
755 PM EDT MON OCT 21 2013 .UPDATE (TONIGHT AND TUESDAY)... 22/00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS AN EXPANSIVE LONGWAVE TROUGH COVERING MUCH OF THE CONUS TO THE EAST OF THE CONTINENTAL DIVIDE. THIS TROUGH IS ANCHORED BY A LARGE CLOSED LOW FEATURES SPINNING OVER THE NORTHERN GREAT LAKES/SOUTHERN ONTARIO. OTHER FEATURE OF NOTE WITHIN THIS BROAD TROUGH IS SHORTWAVE ENERGY DROPPING SOUTHEASTWARD OVER THE CENTRAL AND SOUTHERN PLAINS AND ADVERTISED ON WV IMAGERY BY PRONOUNCED MID/UPPER LEVEL DRYING/SUBSIDENCE IN ITS WAKE. IT IS THIS PIECE OF SHORTWAVE ENERGY THAT WILL EVENTUALLY HAVE SIGNIFICANT INFLUENCE ON OUR WEATHER AS IT PASSAGE TO OUR NORTH PROPELS A WELL-DEFINED COLD FRONT ACROSS THE FLORIDA PENINSULA DURING WEDNESDAY AND WED NIGHT. FOR NOW...THE FORECAST AREA REMAINS WITHIN THE TRANSITION ZONE BETWEEN THE MAIN LONGWAVE TROUGH AND UPPER RIDGING TO OUR SOUTH. AT THE SURFACE...STILL LOOKING AT A VERY WEAK REGIONAL PRESSURE GRADIENT DUE TO THE PRESENCE OF A WEAK AND DECAYING FRONTAL BOUNDARY. THIS BOUNDARY HAS MOVED LITTLE IN THE PAST 24 HOURS...WITH ITS ILL-DEFINED SIGNATURE HOLDING SOMEWHERE NEAR THE I-4 CORRIDOR. SIMILAR TO PREVIOUS DAYS...SEEING A SCATTERING OF INLAND SHOWERS AND STORMS WITHIN THE CONVERGENCE ZONE OF THE EAST COAST AND WEST COAST SEA-BREEZES. EXPECT FOR UP OVER THE NATURE COAST...ALL OF THIS ACTIVITY IS WELL INLAND FROM THE I-75 CORRIDOR. HOWEVER...CAN SEE A BOUNDARY ON REGIONAL RADARS TRYING TO MAKE ITS WAY BACK WESTWARD INTO SUMTER/POLK COUNTIES. WILL HAVE TO WATCH THE PROGRESS OF THIS BOUNDARY...AS ENOUGH WESTWARD MOVEMENT BEFORE THE COMPLETE LOSS OF DAYTIME INSTABILITY COULD SUPPORT AN ISOLATED SHOWER OR TWO BACK INTO WESTERN HERNANDO/PASCO/HILLSBOROUGH COUNTIES LATER THIS EVENING. EITHER WAY...AFTER 04-05Z...ALL THIS ACTIVITY SHOULD DIMINISH AND LEAVE A GENERALLY DRY OVERNIGHT PERIOD. TUESDAY/WEDNESDAY... STARTING AROUND SUNRISE AND CONTINUING THROUGH THE DAY...THE APPROACH AND AMPLIFICATION OF THE UPPER TROUGH INTO THE EASTERN UNITED STATES WILL BOTH BEGIN TO SPREAD BROAD SYNOPTIC SUPPORT/DEEP LAYER QG FORCING FOR ASCENT INTO THE NORTHERN HALF OF THE AREA...BUT ALSO INCREASING UPPER DIVERGENCE WITHIN THE RRQ OF A STRENGTHENING 140+ KNOT UPPER JET. THE FORECAST FOR TUESDAY THEREFORE BECOMES A BIT MORE COMPLEX...WITH LARGE SCALE SYNOPTIC FORCING THE DOMINANT PLAYER TO THE NORTH OF THE I-4 CORRIDOR...AND MESOSCALE SEA-BREEZE/INSTABILITY FACTORS THE DOMINANT DRIVING FORCES ALONG AND SOUTH OF I-4. THE SYNOPTIC INFLUENCES SUGGEST THE HIGHER POPS/RAINFALL COVERAGE DURING THE COURSE OF THE DAY OVER THE FAR NORTH...WHERE LIKELY RAIN CHANCES ARE FORECAST. OVER CENTRAL AND SOUTHERN ZONES...THE FORECAST WILL BE SIMILAR TO PREVIOUS DAYS WITH A SCATTERING OF MAINLY LATE DAY AND INLAND SHOWERS. THEREAFTER ON WEDNESDAY...THE CLOSER APPROACH AND PASSAGE OF THE SHORTWAVE AXIS...AND ARRIVAL OF THE COLD FRONT...WILL SPREAD BROAD SYNOPTIC SUPPORT FURTHER SOUTH AND PROVIDE A CHANCE FOR A PERIOD OF ORGANIZED SHOWERS/STORMS FOR OUR CENTRAL AND SOUTHERN ZONES. HAVE A GOOD EVENING EVERYONE! && .AVIATION... LIMITED AFTERNOON CONVECTION NOW DECAYING WELL EAST OF TERMINALS. EXPECT MVFR FROM LATE NIGHT TO AFTER SUNRISE...WITH LCL IFR POSSIBLE AT LAL AND PGD. LOW CIGS WILL GENERALLY DOMINATE WITH BR/FG PLAYING A SECONDARY PART. A FEW SHRA MAY DRIFT ONSHORE EARLY AFTERNOON... NORTH...OR LATE MORNING SOUTH AND MOVE EAST IN A SEA BREEZE. LAL IS AN EXCEPTION AND COULD SEE TSRA. && .MARINE... A WEAK PRESSURE PATTERN WILL REMAIN IN PLACE THROUGH TUESDAY... WITH FLOW DOMINATED BY THE AFTERNOON SEA BREEZE AND OVERNIGHT LAND BREEZE. A STRONG COLD FRONT WILL THEN MOVE THROUGH THE WATERS WEDNESDAY AND WEDNESDAY EVENING...WITH HIGH PRESSURE BUILDING IN FROM THE NORTH FOR THE END OF THE WORK WEEK. WINDS AND SEAS WILL REMAIN BELOW HEADLINE THRESHOLDS THROUGH TUESDAY NIGHT...BUT ARE LIKELY TO REACH EXERCISE CAUTION OR ADVISORY LEVELS BY LATER WEDNESDAY THROUGH FRIDAY IN THE WAKE OF THE STRONG COLD FRONT. && .PRELIMINARY POINT TEMPS/POPS... TPA 75 86 75 82 / 10 30 50 50 FMY 73 88 75 84 / 10 20 40 50 GIF 72 88 72 79 / 20 40 50 50 SRQ 73 86 75 82 / 10 20 50 50 BKV 69 86 71 79 / 10 50 50 40 SPG 77 87 76 81 / 10 20 50 50 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/MARINE...MROCZKA AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS MIAMI FL
1022 AM EDT SUN OCT 20 2013 .UPDATE... DO NOT PLAN ANY CHANGES TO MORNING UPDATES WITH THE 12Z MFL SOUNDING INDICATING SUBSIDENCE CAP STILL IN PLACE WITH A STABLE LAYER BETWEEN 800 AND 650 MB. ATMOSPHERE ALSO REMAINS QUITE DRY WITH PWAT AT AROUND 1.5 INCHES. THE LOWER LAYERS HAVE MOISTENED UP WITH DEW POINTS BACK INTO THE LOWER AND MID 70S SO CU FIELD ALREADY FORMING AND COULD HAVE SOME EARLY ONSET OF LOW TOPPED SHOWERS AND IF ANY CAN OVERCOME THE CAP, THEN A THUNDERSTORM CANNOT BE RULED OUT WITH QUITE A BIT OF LIGHTNING LATE YESTERDAY OVER WESTERN PALM BEACH COUNTY. THE HRRR DOES SHOW THIS TREND WITH LATE AFTERNOON CONVECTION OVER THE SAME AREA. WILL WAIT FOR EARLIER THIS AFTERNOON, BUT MAY NEED TO EXPAND THE CHANCE POP COVERAGE A LITTLER FARTHER TO THE EAST BUT NOTHING MORE DRASTIC THAN THAT PLANNED AT THIS TIME. KOB && .PREV DISCUSSION... /ISSUED 657 AM EDT SUN OCT 20 2013/ AVIATION... A WEAK, DIFFUSE BOUNDARY ACROSS THE FLORIDA PENINSULA HAS BEEN A FOCAL POINT FOR SOME ISOLATED TO SCATTERED SHOWERS. THIS BOUNDARY WILL CONTINUE TO AFFECT THE WEATHER TODAY, WITH A CHANCE OF SHOWERS, MAINLY IN THE LAKE REGION OF SOUTH FLORIDA, WHICH SHOULD NOT IMPACT ANY TAF SITES. HOWEVER, THERE IS A VERY LOW POSSIBILITY THAT A BRIEF CONVECTIVE CELL COULD IMPACT ANY GIVEN TAF SITE. OTHERWISE, VFR CONDITIONS ARE EXPECTED. ALSO, BEING SOUTH OF THE BOUNDARY WILL KEEP WINDS GENERALLY SOUTHERLY TODAY, PICKING UP TO 5 TO 10 KTS. THEY WILL GO LIGHT AND VARIABLE AGAIN TONIGHT. PREV DISCUSSION... /ISSUED 358 AM EDT SUN OCT 20 2013/ DISCUSSION... A WEAK SURFACE TROUGH JUST WEST OF THE FLORIDA KEYS CONTINUES TO GENERATE A FEW SHOWERS WEST AND SOUTH OF KEY WEST EARLY THIS MORNING. THIS TROUGH IS EXPECTED TO LINGER THROUGH THE DAY AND ACT AS A FOCUS FOR ADDITIONAL SHOWERS MAINLY ACROSS THE GULF WATERS. FOR SOUTH FLORIDA...SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL AGAIN BE POSSIBLE THROUGH THE AFTERNOON HOURS. SOUTHWEST FLOW ALOFT WILL CONTINUE TO FUNNEL LOW LEVEL MOISTURE INTO THE AREA. THIS COMBINED WITH WEAK SEA BREEZE INTERACTIONS SHOULD BE ENOUGH TO SPARK A FEW SHOWERS AND STORMS MAINLY ACROSS THE INTERIOR. FOR MONDAY INTO TUESDAY...UPPER RIDGING ENTRENCHED ACROSS THE FLORIDA PENINSULA WILL SLOWLY BEGIN TO BREAK DOWN AS A BROAD H5 SHORTWAVE BEGINS TO SWING DOWN THROUGH THE MIDSOUTH STATES. SLIGHT CHANCES FOR AFTERNOON SHOWERS AND A FEW THUNDERSTORMS WILL BE PREVALENT EACH DAY AS A SLIGHTLY DEEPER MOISTURE AXIS PUSHES INTO SOUTH FLORIDA AHEAD OF AN APPROACHING COLD FRONT. THE COLD FRONT IS STILL EXPECTED TO PUSH INTO THE SOUTH FLORIDA AREA BY WEDNESDAY. MODELS TEND TO BE IN GOOD AGREEMENT ON THE TIMING OF THE FRONTAL PASSAGE. NORTH TO NORTHEASTERLY SURFACE FLOW WILL THEN PREVAIL AND INCREASE THROUGH THE END OF THE WEEK DUE TO A RATHER TIGHT PRESSURE GRADIENT BETWEEN LOWER PRESSURE TO THE SOUTH AND STRONG HIGH PRESSURE ACROSS THE SOUTHEAST STATES. THIS WILL ALLOW NOTICEABLY MILDER TEMPERATURES TO FILTER ACROSS THE AREA THURSDAY INTO NEXT WEEKEND. WOULD NOT BE SURPRISED TO SEE MORNING LOWS IN THE 50S ACROSS INTERIOR AREAS FRIDAY MORNING. THE SOUTHWARD EXTENT OF THE DRY AIR PUSH IN THE WAKE OF THE FRONTAL PASSAGE IS UNCLEAR AT THIS TIME. BOTH THE GFS AND ECMWF SEEM TO KEEP AN OVERRUNNING MOISTURE AXIS JUST SOUTH OF THE AREA ACROSS THE FLORIDA STRAITS. ANY FLUCTUATION OVER THE NEXT FEW DAYS WOULD GREATLY INFLUENCE RAIN CHANCES TOWARD THE END OF THE WEEK. SUBSEQUENT MODEL RUNS WILL NEED TO BE MONITORED CLOSELY FOR CONSISTENCY. MARINE... TRANQUIL MARINE CONDITIONS WILL CONTINUE INTO EARLY NEXT WEEK WITH A PREVAILING E-SE WIND AT 10 KNOTS OR LESS WITH CORRESPONDING SEAS AT 3 FEET OR LESS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 89 75 88 74 / 20 10 20 20 FORT LAUDERDALE 88 78 88 77 / 20 20 20 20 MIAMI 87 77 88 76 / 20 20 20 20 NAPLES 88 74 87 72 / 20 10 20 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
1039 PM EDT MON OCT 21 2013 .UPDATE... ADJUSTED SLIGHT POPS ONCE AGAIN FARTHER NORTH THROUGH TONIGHT ACROSS MUCH OF CENTRAL GEORGIA BASED ON COMBINATION OF PROGGED WEAK VORT MAX LOCATION AND GENERAL CONSENSUS OF MODEL PRECIP...THOUGH A FEW OUTLIERS INDICATING POTENTIAL ACROSS NORTH GEORGIA AS WELL. NOT BUYING INTO THIS RIGHT NOW...THOUGH RECENT HISTORY IN A SIMILAR SYSTEM PROVED OTHERWISE. WILL CONTINUE TO UPDATE AS NECESSARY...THOUGH ANY RAIN TOTALS ARE EXPECTED TO BE LIGHT. LATEST NAM CONDENSATION PRESSURE DEFICITS ARE A BIT LOWER AND MORE EXPANSIVE THAN EARLIER SO HAVE EXPANDED SOUTHEASTERN FOG POTENTIAL. REST OF FORECAST LOOKS TO BE ON TRACK AND PREVIOUS DISCUSSION FOLLOWS... BAKER && .PREV DISCUSSION... /ISSUED 813 PM EDT MON OCT 21 2013/ PREV DISCUSSION... /ISSUED 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 REDEVELOPING 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... 00Z UPDATE... MAINLY VFR CONDITIONS EXPECTED FOR MOST SITES...WHILE MVFR VSBYS POSSIBLE AT KAHN AND KMCN IN EARLY MORNING. ALSO POTENTIAL FOR MVFR CIGS BUILDING INTO KMCN FOR EARLY MORNING BUT BEST CHANCE LOOKS TO BE SOUTH AND EAST. CIGS GENERALLY NEAR 10 KFT WITH POSSIBLE LOWERING TO NEAR 6-8 KFT AND SCATTERING OUT BY TUESDAY EVENING AS WEAK FRONT PUSHES SOUTHEASTWARD. FORECAST PRECIP CHANCES TOO LOW TO INCLUDE IN TAF FOR NOW BUT BEST CHANCE FOR ANY RAIN WOULD BE IN AFTERNOON. IF THIS WERE TO OCCUR...THEN WOULD EXPECT CIGS OF 6-8 KFT EARLIER IN AFTERNOON. WINDS MAINLY CALM OVERNIGHT BECOMING WEST AT NEAR 7 KTS OR LESS TUESDAY...THEN SWITCHING NW BY EVENING WITH FRONTAL PASSAGE. //ATL CONFIDENCE...00Z UPDATE... MEDIUM CONFIDENCE ON RAIN CHANCES...EARLY MORNING CIGS NEAR KMCN AND AFTERNOON CIGS FOR ALL SITES. HIGH CONFIDENCE ALL ELSE. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 54 72 50 65 / 20 30 20 0 ATLANTA 55 70 49 61 / 10 30 20 0 BLAIRSVILLE 45 67 42 54 / 5 30 20 5 CARTERSVILLE 47 70 45 59 / 10 30 10 0 COLUMBUS 59 77 54 69 / 20 20 20 0 GAINESVILLE 53 69 49 60 / 10 30 20 0 MACON 57 75 49 70 / 20 30 20 0 ROME 46 70 44 60 / 5 30 10 5 PEACHTREE CITY 50 72 49 63 / 20 20 20 0 VIDALIA 63 75 55 74 / 30 40 30 0 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...DEESE/BAKER LONG TERM....01 AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
813 PM EDT MON OCT 21 2013 .UPDATE... HAVE MAINLY UPDATED EVENING FORECAST TO INCLUDE SLIGHT CHANCE POPS FOR RAIN IN THE FAR SOUTHERN TIER OF THE CWA BASED ON OBSERVED BANDING OF UPSTREAM LOW REFLECTIVITY AND MODEL CONSENSUS IN PRESENCE OF WEAK VORT MAX PROGGED TO TRAVERSE PORTIONS OF CENTRAL GA OVERNIGHT. ALSO TRENDED DEWPOINTS A BIT HIGHER IN MOST AREAS BASED ON RECENT OBS AND CONTINUED PRESENCE OF UPPER CLOUD DECK. BEST CHANCE FOR AREAS OF FOG IN THE EARLY MORNING LOOKS TO BE SOUTH AND EAST OF MACON BASED ON NAM CONDENSATION PRESSURE DEFICITS. REST OF FORECAST LOOKS TO BE ON TRACK AND PREVIOUS DISCUSSION FOLLOWS... BAKER && .PREV DISCUSSION... /ISSUED 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 REDEVELOPING 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... 00Z UPDATE... MAINLY VFR CONDITIONS EXPECTED FOR MOST SITES...WHILE MVFR VSBYS POSSIBLE AT KAHN AND KMCN IN EARLY MORNING. ALSO POTENTIAL FOR MVFR CIGS BUILDING INTO KMCN FOR EARLY MORNING BUT BEST CHANCE LOOKS TO BE SOUTH AND EAST. CIGS GENERALLY NEAR 10 KFT WITH POSSIBLE LOWERING TO NEAR 6-8 KFT AND SCATTERING OUT BY TUESDAY EVENING AS WEAK FRONT PUSHES SOUTHEASTWARD. FORECAST PRECIP CHANCES TOO LOW TO INCLUDE IN TAF FOR NOW BUT BEST CHANCE FOR ANY RAIN WOULD BE IN AFTERNOON. IF THIS WERE TO OCCUR...THEN WOULD EXPECT CIGS OF 6-8 KFT EARLIER IN AFTERNOON. WINDS MAINLY CALM OVERNIGHT BECOMING WEST AT NEAR 7 KTS OR LESS TUESDAY...THEN SWITCHING NW BY EVENING WITH FRONTAL PASSAGE. //ATL CONFIDENCE...00Z UPDATE... MEDIUM CONFIDENCE ON RAIN CHANCES...EARLY MORNING CIGS NEAR KMCN AND AFTERNOON CIGS FOR ALL SITES. HIGH CONFIDENCE ALL ELSE. && .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 / 10 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/BAKER LONG TERM....01 AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1219 AM CDT SUN OCT 20 2013 .DISCUSSION... 927 PM CDT NO CHANGES TO CURRENT FROST ADVISORY. LATEST SATELLITE/RADAR IMAGERY DEPICTING CLOUD COVER ISOLATED LIGHT SHOWERS STILL ACROSS THE CWA...ASSOCIATED WITH UPPER LEVEL WAVE/TROUGH AND SURFACE REFLECTION. ALTHOUGH LATEST RAP ANALYSIS IS INDICATING SOME PERSISTENT WEAK WAA ACROSS NORTH CENTRAL ILLINOIS...THIS SHOULD WEAKEN OVER THE NEXT SEVERAL HOURS AS TROUGH DEPARTS TO THE EAST. CLEARING SKIES AND DIMINISHING WINDS SHOULD ALLOW FOR TEMPS TO STILL DROP OVERNIGHT...WITH THIS ALREADY BEING OBSERVED IN LOCATIONS THAT SAW SOME PARTIAL CLEARING EARLY ON. SO HAVE MADE MINOR ADJUSTMENTS TO TEMPS TONIGHT WITH CURRENT ADVISORY LOCATION STILL APPEARING TO BE ON TRACK. DESPITE THIS BEING THE PREFERRED LOCATION FOR BETTER FROST DEVELOPMENT...PATCHY FROST CANNOT BE RULED OUT BRIEFLY LATE TONIGHT INTO EARLY SUNDAY MORNING FOR THE REMAINDER OF THE CWA. ALSO...LATEST DEWPOINT TRENDS COINCIDING WITH TEMPS TONIGHT COULD ALLOW FOR PATCHY FOG...AND HAVE ADDED TO THE GRIDS PRIMARILY FOR NORTHERN ILLINOIS. RODRIGUEZ //PREV DISCUSSION... 243 PM CDT REST OF THE WEEKEND...TONIGHT THROUGH SUNDAY NIGHT... WEATHER TO BE CONTROLLED BY THE LARGE UPPER TROUGH EXTENDING ACROSS WESTERN HUDSON BAY SOUTHWARD TO THE OZARKS EARLY THIS AFTERNOON MOVING TO EASTERN CANADA AND NEW ENGLAND OVERNIGHT AND DURING SUNDAY. THIS WILL ALLOW WEAK UPPER RIDGING TO OCCUR OVER THE GREAT LAKES AND MIDWEST SUNDAY AS THIS UPPER TROUGH ROTATES NORTHEASTWARD AND ANOTHER UPPER TROUGH DEEPENS OVER THE UPPER MIDWEST AND THE UPPER AND MID MS VALLEY DURING SUNDAY AND SUNDAY NIGHT. HAVE RETAINED MENTION OF FROST ACROSS ACROSS NORTH CENTRAL AND NORTHEAST IL OUTSIDE OF THE METRO AREA THOUGH CONFIDENCE IS NOT PARTICULARLY HIGH AS WARM AIR ADVECTION CLOUDS CONTINUE TO SPREAD FROM IA ACROSS NORTHERN IL LATER THIS AFTERNOON AND TONIGHT SHOULD BE ENOUGH BREAKS DURING THE OVERNIGHT FOR AREAS OF FROST. A BACKING AND INCREASING LOW LEVEL FLOW DURING SUNDAY WILL ALLOW SOME MODERATION IN TEMPERATURES AS SIGNIFICANT WARM AIR ADVECTION OCCURS. WHILE CLOUDS ARE EXPECTED TO GRADUALLY BE ON THE INCREASE DURING THE DAY THE WARM AIR ADVECTION ITSELF SHOULD PUSH SUNDAY HIGH TEMPERATURES UP TO THE UPPER 50S NORTH TO MID 60S SOUTHWEST. DESPITE THE INCREASING CLOUDINESS AS THE UPPER WAVE ROTATES ACROSS FROM THE NORTHERN PLAINS TO OVER MN AND IA ANY REAL THREAT OF RAIN WILL REMAIN NORTH OF THE WI BORDER WHERE THE BEST FORCING WILL BE. AS THE UPPER TROUGH MOVES TO WESTERN WI AND NORTHWEST AND WEST CENTRAL IL DURING SUNDAY NIGHT POPS WILL RISE TO SLIGHT CHANCE AS THE UPPER TROUGH APPROACHES AND AN ASSOCIATED COLD FRONT PUSHES SOUTHEASTWARD ACROSS THE LOCAL FORECAST AREA. MONDAY THROUGH SATURDAY... THE MODERATION IN TEMPERATURES WILL BE SHORT LIVED AS THE UPPER FLOW STARTS TO RETURN TO STRONG NORTHWESTERLY ACROSS THE AREA BY MONDAY NIGHT WITH A SERIES OF SHORT WAVES ROTATING THROUGH THE UPPER TROUGH PROVIDING REINFORCING SHOTS OF VERY COOL AIR THROUGH THE WEEK KEEPING HIGH TEMPERATURES DOWN TO MID 40S TO LOWER 50S...WITH LOWS FROM UPPER 20S TO MID 30S. USING THE 12Z ECMWF AS A GOOD COMPROMISE BETWEEN MODEL SOLUTIONS THE MAIN PERIODS FOR A THREAT OF PRECIPITATION ARE FROM LATER TUESDAY INTO WEDNESDAY AS A SHORT WAVE APPROACHES AND MOVES ACROSS THE AREA AND THEN NEXT SATURDAY AS AN UPPER TROUGH MOVES EAST OVER THE UPPER MIDWEST AND THE MID AND LOWER MO VALLEY REGIONS PUSHING ANOTHER COLD FRONT INTO THE LOCAL AREA DURING THE DAY. WITH THE TUESDAY-TUESDAY NIGHT SHORT WAVE TROUGH PASSAGE THE COLUMN COOLS TO BELOW 0C ACROSS NORTH CENTRAL AND FAR NORTHEAST IL DURING THURSDAY NIGHT SO ANY REMAINING RAIN MAY MIX WITH OR CHANGE TO SNOW BEFORE ENDING. WITH SEVERAL SHORT WAVES TO BE ROTATING THROUGH THE MEAN UPPER TROUGH THERE COULD BE OTHER TIME-FRAMES WHEN THERE WOULD BE AT LEAST A SLIGHT CHANCE TO LOW END CHANCE OF PRECIPITATION BUT TIMING OF ANY ONE OF THESE SMALLER DISTURBANCES IS PRETTY MUCH FUTILE THESE FEATURES TYPICALLY GET LOST IN THE NOISE OF THE PROGS. TRS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * PERIOD OF STRONG SOUTH WINDS WITH GUSTS AROUND 25 KT THIS AFTERNOON AND POSSIBLY INTO THIS EVE. * SCATTERED -SHRA WITH POSSIBLE TEMPORARY MVFR CONDITIONS THIS EVE. * GUSTY WEST WINDS LATE SUNDAY NIGHT. //DISCUSSION...UPDATED 06Z... TEMPORARY RIDGING WILL PREVAIL THROUGH SUNRISE BEFORE SOUTHERLY WINDS ENSUE. THESE WILL INCREASE IN SPEED THIS AFTERNOON AS STRONG LOW PRESSURE DEVELOPS ACROSS THE UPPER MISSISSIPPI VALLEY. SOME PERIODIC GUSTINESS MAY CONTINUE IN THE EVE. AS A STRONG COLD FRONT WRAPS AROUND THIS LOW AND APPROACHES THE TAF SITES THIS EVE...SCATTERED SHOWERS ARE ALSO POSSIBLE. IF THESE MATERIALIZE...TEMPORARY MVFR CONDITIONS COULD EASILY ACCOMPANY THEM. THE STRONG COLD FRONT WILL MOVE FROM WEST TO EAST ACROSS THE TAF SITES SUNDAY NIGHT AND TURN THE WINDS WESTERLY WITH A RE- INCREASE IN GUSTINESS. A BRIEF PERIOD OF MVFR CIGS ARE ALSO POSSIBLE WITH THIS FEATURE. //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM IN WINDS THIS AFTERNOON AND TONIGHT. HIGH CONFIDENCE THAT WINDS WILL BE BETWEEN 160 AND 210 THIS AFTERNOON. * LOW IN SHRA THIS EVE AND POSSIBLE MVFR CONDITIONS. //OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z... MONDAY...MVFR CIGS LIKELY. TUESDAY...MVFR CIGS POSSIBLE. CHANCE OF -RA OR -RSSN. WEDNESDAY...MVFR CIGS POSSIBLE...MAINLY EARLY. THURSDAY AND FRIDAY...PROBABLY VFR. MTF/IZZI && .MARINE... 334 PM CDT A VERY ACTIVE PERIOD ON THE WAY ACROSS THE LAKE AS A SERIES OF LOW PRESSURE SYSTEMS AND A UNSEASONABLY COLD AIR MASS COMBINE TO BRING STRONG WINDS MOST OF THE FORECAST PERIOD. WEST WINDS OVER THE SOUTH HALF WILL RAMP UP TO 30 KT THIS EVENING BEFORE DIMINISHING SOME LATE. THERE WILL BE A BRIEF PERIOD OF LIGHTER SOUTH WINDS SUNDAY MORNING BEFORE LOW PRESSURE APPROACHES FROM THE WEST LATER SUNDAY AND SOUTHERLY WINDS INCREASE. SOME UNCERTAINTY EXISTS AS TO THE TRACK AND TIMING OF THE LOW...BUT THERE IS GOOD AGREEMENT AMONGST GUIDANCE FOR SOUTH TO SOUTHWEST WINDS UP TO GALE FORCE SOMETIME SUNDAY EVENING INTO THE OVERNIGHT FOR THE CENTRAL AND SOUTHERN PORTION OF THE LAKE. THEREFORE HAVE ISSUED A GALE WATCH FOR THE CENTRAL AND SOUTH STARTING AT 00Z SUNDAY. A VERY STRONG COLD FRONT WILL SWEEP ACROSS THE LAKE AS THE LOW LIFTS TO EASTERN LAKE SUPERIOR BY EARLY MONDAY AND DEEPENS. SOUTHWEST GALES WILL QUICKLY TRANSITION TO WESTERLY GALES ON THE CENTRAL AND SOUTH...WHILE WESTERLY GALES WILL DEVELOP OVER THE NORTH TOWARD EARLY MONDAY MORNING. A WINTER LIKE AIRMASS WILL POUR ACROSS THE LAKE...SUPPORTING EXTREMELY UNSTABLE CONDITIONS AND EFFICIENT MIXING. WEST GALES WILL INCREASE TO 40 KT ON THE NORTH PART OF THE LAKE ON MONDAY...WITH 35 KT CONTINUING TO THE SOUTH. THERE THEN APPEARS TO BE ANOTHER COLD FRONT OR SECONDARY SURGE OF COLD AIR MONDAY NIGHT EXPECTED TO KEEP GALES GOING ON THE NORTH ALL THE WAY INTO TUESDAY MORNING. THUS HAVE EXTENDED THE GALE WATCH THERE UNTIL 15Z TUESDAY. FOR THE NEARSHORE WATERS...HAVE EXTENDED THE SMALL CRAFT ADVISORY FOR GARY AND POINTS EAST UNTIL 9Z SUNDAY AS WAVES WILL BE SLOWER TO SUBSIDE. WILL THEN LIKELY NEED A SMALL CRAFT ADVISORY FOR ALL THE NEARSHORE ZONES SOMETIME SUNDAY EVENING THROUGH MONDAY EVENING...THEN AT LEAST A PORTION OF THE INDIANA NEARSHORE ALL THE WAY THROUGH TUESDAY EVENING DUE TO WAVES. RC && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012 UNTIL 8 AM SUNDAY. IN...NONE. LM...GALE WATCH...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777- LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 PM SUNDAY TO 4 AM TUESDAY. GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...3 AM MONDAY TO 10 AM TUESDAY. SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM SUNDAY. && $$ 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 MARQUETTE MI
342 PM EDT SUN OCT 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT SUN OCT 20 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND ERN CONUS. ONE UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER THE DAKOTAS WHILE ANOTHER STRONGER PV ANOMALY WAS DROPPING TO THE SSE THROUGH CNTRL MANITOBA. 290K ISENTROPIC LIFT AHEAD OF A SFC LOW OVER THE CNTRL DAKOTAS SUPPORTED AREAS OF RAIN OVER THE ERN DAKOTAS INTO WRN MN. 850 MB TEMPS AROUND -4C HELPED TO MAINTAIN A LAKE INDUCED TROUGH OVER LAKE SUPERIOR IN THE LIGHT WIND REGIME. ISOLD LAKE EFFECT -SHRA LINGERED INTO NW UPPER MI AND ERN LAKE SUPERIOR. THE MODELS WERE IN RELATIVELY GOOD AGREEMENT WITH THE SHORTWAVES AND SFC LOW MOVING INTO THE WRN GREAT LAKES. AS THE SFC LOW TRACKS FROM WRN MN SUNDAY MORNING TO THE SE END OF LAKE SUPERIOR EARLY MON MORNING...DEEP LAYER QVECTOR CONV AND 285K-295K ISENTROPIC LIFT WILL SUPPORT AN AREA OF PCPN MOVING INTO SW UPPER MI SUN AFTERNOON AND ACROSS THE CWA SUN NIGHT. PCPN AMOUNTS IN THE 0.25 TO 0.50 INCH RANGE ARE EXPECTED. MODEL FCST SOUNDINGS...AND WET-BULB ZERO HEIGHTS SUPPORT THE POTENTIAL FOR A SOME SNOW ACCUMULATION OVER THE HIGHER TERRAIN OF THE WEST HALF OF UPPER MI. WITH ONLY LIGHT TO MODERATE SNOWFALL RATES EXPECTED...AND RELATIVELY LOW SNOW/WATER RATIO VALUES BELOW 10/1...ANY SNOW ACCUMULATION SHOULD GENERALLY REMAIN AT OR BELOW 2 INCHES. THERE MAY ALSO BE SOME ADDITIONAL LAKE ENHANCED SNOW INTO NW UPPER MI LATE AS WNW WINDS STRENGTHEN BEHIND THE LOW. .LONG TERM...(MONDAY NIGHT THROUGH SUNDAY) ISSUED AT 342 PM EDT SUN OCT 20 2013 MON NIGHT...MODELS SHOW THE ELONGATED SFC TROUGH FM LOW JUST SOUTH OF JAMES BAY WILL BE SITUATED OVER NRN LAKE SUPERIOR ON MONDAY. AS THE STRONG SHORTWAVE/CLOSED MID-UPR LVL LOW FM MANITOBA BEGINS TO MOVE ACROSS LAKE SUPERIOR AND UPPER MI MON NIGHT THIS WILL PROPEL THE SFC TROF ACROSS WRN LAKE SUPERIOR AND WRN UPR MI MON EVENING AND ACROSS ERN LAKE SUPERIOR AND CENTRAL/ERN UPR MI LATE MON NIGHT. THE TIMING OF THIS TROUGH WILL BE IMPORTANT AS WINDS WILL SHIFT FM WESTERLY TO NNW AND BRING STRONGLY CONVERGENT CYCLONIC FLOW TO FOCUS LAKE EFFECT SHOWERS INTO WESTERN UPPER MI MON EVENING AND ACROSS THE REST OF THE NORTH HALF UPPER MI LATE MON NIGHT. 850 MB TEMPS AROUND -6C OVER LAKE SUPERIOR ALONG WITH DEEP MOISTURE AND STRONG CYCLONIC FLOW WILL RESULT IN PLENTY OF LAKE ENHANCED PCPN OVER THE NORTHERN HALF OF THE UPPER MI MON NIGHT INTO TUE MORNING. MODEL SOUNDINGS INDICATE THERE SHOULD BE ENOUGH LOW LEVEL COLD AIR FOR AT LEAST SEVERAL INCHES OF WET ACCUMULATING SNOW OVER THE HIGHER TERRAIN OF WEST HALF OF UPPER MI...ESPECIALLY WHERE UPSLOPE NW TO NNW FLOW PREVAILS. CONFIDENCE IN SNOW AMOUNTS IS STILL ONLY AVERAGE GIVEN THE MODEL DIFFERENCES WITH TIMING OF THE TROUGH AND SHIFT OF LOW LEVEL WINDS. THE BEST CHANCE FOR SIGNIFICANT SNOW ACCUMULATIONS WILL BE OVER THE HIGHER TERRAIN OF THE WEST FROM NEAR IRONWOOD TROUGH ROCKLAND TO TWIN LAKES AND MOHAWK AND OVER THE HURON MOUNTAINS OF BARAGA AND MARQUETTE COUNTIES. SOME ACCUMULATING SNOW WILL ALSO BE LIKELY FROM THE HURON MOUNTAINS TO NEGAUNEE MON NIGHT. AT THIS POINT...IT APPEARS THAT SNOW ACCUMULATION WILL STAY BELOW WARNING CRITERIA FOR TWO MAIN REASONS. ONE...MODEL SNDGS SUGGEST THE BEST DENDRITIC SNOW GROWTH LAYER WILL BE ABOVE THE BEST MODEL OMEGA/LIFT WITH SYSTEM WHICH WILL LIKELY LIMIT SNOW/WATER RATIOS TO AROUND 8/1. TWO...MODEL DEEP LAYER Q-VECT CONV INDICATES THAT THE BEST ENHANCEMENT/SYNOPTIC SCALE FORCING FOR LAKE SNOW SHOWERS WILL BE BEFORE THE PASSAGE OF THE TROUGH OR BEFORE THE WINDS SHIFT FROM W TO NNW. I DON`T DOUBT THAT THERE COULD BE A QUICK INCH OR TWO OF SNOW WITH GOOD CONVERGENCE AND A BAND OF HEAVIER SNOW RIGHT ALONG THE TROUGH PASSAGE. BUT AFTER THE TROUGH PASSAGE...PURE LAKE EFFECT WILL TAKE OVER...AND GIVEN THAT 850 MB TEMPS FALL AT BEST TO -7C OVER WRN LAKE SUPERIOR EQUATING TO A LAKE DELTA-T OF 16C...WOULD EXPECT NO MORE THAN UP TO 3 INCHES OF ADDITIONAL ACCUMULATION AT BEST THROUGH TUE MORNING OVER FAVORED HIGHER TERRAIN LOCATIONS. FOR THIS REASON WILL NOT ISSUE A WATCH BUT WILL CONTINUE TO HIGHLIGHT SNOW ACCUMULATION IN A SPS. TUE-FRI...WITH THE MEAN LONG WAVE TROUGH REMAINING OVER THE GREAT LAKES AND ERN CONUS...NW FLOW AND A SERIES OF WEAK CLIPPER SHRTWVS ARE EXPECTED TO MOVE THROUGH THE UPPER LAKES. THIS WILL BRING PERIODS OF SNOW SHOWERS...MIXED WITH RAIN AT TIMES...THAT WILL BE ENHANCED BY LAKE SUPERIOR AS 850 MB TEMPS CONTINUE TO FALL INTO THE -8C TO -10C RANGE. LOCATIONS GENERALLY FAVORED BY NW FLOW WILL SEE BEST CHANCE FOR PCPN. SOME ADDITIONAL ACCUMULATING SNOW IS POSSIBLE AND AS IS TYPICAL IN EARLY SEASON LAKE EFFECT REGIMES...GRAUPEL WILL LIKELY ALSO BE MIXED WITH ANY RAIN/SNOW SHOWERS. LAKE EFFECT PCPN WILL DIMINISH BY FRIDAY AS UPPER TROUGH MOVES EAST AND RIDGING BUILDS IN FM THE WEST. NEXT WEEKEND...MODELS SHOW PLENTY OF VARIABILITY OUT TO DAYS 6 AND 7 OF THE FCST. ALL MODELS SHOW ANOTHER CLIPPER SHORTWAVE ROUNDING THE WRN CONUS RIDGE AND DIVING INTO THE NRN PLAINS AND UPPER GREAT LAKES REGION BUT TRACK AND TIMING OF SHORTWAVE IS UNCERTAIN AT THIS TIME. FOR NOW WILL GO WITH A GENERAL CONSENSUS FCST AND INCLUDE CHC POPS FOR RAIN/SNOW SHOWERS AND TEMPS REMAINING BLO NORMAL FOR NEXT SAT-SUN. THE 00Z ECMWF ADVERTISES YET ANOTHER CLIPPER SHORTWAVE MOVING IN FOR THE EARLY PART OF THE FOLLOWING WORK WEEK WHICH WOULD USHER IN THE COLDEST AIRMASS YET OF THE SEASON WITH 850 MB TEMPS FALLING AOB -12C. IF THIS SOLUTION HOLDS TRUE...THE LAST FEW DAYS OF OCTOBER WILL FEATURE CONTINUED BELOW NORMAL TEMPS AND MORE LAKE EFFECT PCPN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 242 PM EDT SUN OCT 20 2013 TIMING OF THE APPROACHING SNOW AND LOWER CEILINGS HAS BEEN VERY TRICKY TODAY...MADE TRICKIER BY FOG/STRATUS THIS MORNING ACROSS THE HIGHER ELEVATIONS OF THE W HALF OF UPPER MI. THIS MAINLY INFLUENCED SAW...WHICH WAS RIGHT ON THE CLEARING LINE THANKS TO LIGHT DOWNSLOPE WINDS MUCH OF THE MORNING. CEILINGS HAVE BEEN HOVERING BETWEEN HIGH END MVFR AND VFR EARLY THIS AFTERNOON...WITH THE RAIN/SNOW LINE AND MVFR TO IFR CEILINGS NEARING FROM N CENTRAL WI THIS AFTERNOON. EXPECT DETERIORATING CONDITIONS AT ALL 3 SITES...WITH RAIN SLOWLY MIXING WITH SNOW OVERNIGHT. THE MIX OF RAIN AND SNOW WILL LIKELY CHANGE OVER TO ALL SNOW AT IWD SHORTLY BEFORE DAYBREAK AS COOLER AIR RUSHES IN ON FAVORABLE W-NW WINDS. THE CHANGE OVER SHOULD TAKE A COUPLE MORE HOURS AT CMX...WITH A LOW TEMP IN THE MID 30S OVERNIGHT. STRONGER W WINDS WILL BE COMMON STARTING 09-15Z W TO E...WITH GUSTS OF 25-30KTS /STRONGEST AT CMX/...AS CEILINGS SLOWLY IMPROVE AS THE BULK OF THE MOISTURE EXITS AS THE SFC LOW PUSHES INTO E QUEBEC. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT SUN OCT 20 2013 LOW PRESSURE MOVEING OUT OF THE DAKOTAS WILL BEGIN TO INTENSIFY OVER THE UPPER MISSISSIPPI VALLEY TODAY AND THEN MOVE THROUGH THE UPPER GREAT LAKES TONIGHT AND MONDAY. AS THIS OCCURS...WINDS WILL STRENGTHEN ACROSS THE LAKE...FIRST OUT OF THE SOUTH TO SOUTHEAST AHEAD OF THE LOW THIS EVENING AND THEN OUT OF THE WEST BEHIND THE LOW LATE TONIGHT INTO MONDAY. THERE STILL ARE SOME DIFFERENCES IN THE EXACT TRACK AND STRENGTH OF THE LOW AS IT MOVES ACROSS LAKE SUPERIOR ON MONDAY...SO WIND SPEED/DIRECTIONS ARE STILL UNCERTAIN. AT THIS TIME...IT APPEARS THE STRONGEST WINDS WILL BE BEHIND THE LOW ON MONDAY AND MONDAY NIGHT...WHEN WEST GALES TO 35-40KTS VEERING TO THE NORTH ARE EXPECTED. ONCE THE LOW DEPARTS THE AREA...EXPECT NORTHWESTERLY WINDS UP TO 25KTS TO REMAIN OVER LAKE SUPERIOR INTO WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY AFTERNOON FOR LSZ265>267. GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR LSZ264. GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...VOSS AVIATION...KF MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
243 PM EDT SUN OCT 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT SUN OCT 20 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND ERN CONUS. ONE UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER THE DAKOTAS WHILE ANOTHER STRONGER PV ANOMALY WAS DROPPING TO THE SSE THROUGH CNTRL MANITOBA. 290K ISENTROPIC LIFT AHEAD OF A SFC LOW OVER THE CNTRL DAKOTAS SUPPORTED AREAS OF RAIN OVER THE ERN DAKOTAS INTO WRN MN. 850 MB TEMPS AROUND -4C HELPED TO MAINTAIN A LAKE INDUCED TROUGH OVER LAKE SUPERIOR IN THE LIGHT WIND REGIME. ISOLD LAKE EFFECT -SHRA LINGERED INTO NW UPPER MI AND ERN LAKE SUPERIOR. THE MODELS WERE IN RELATIVELY GOOD AGREEMENT WITH THE SHORTWAVES AND SFC LOW MOVING INTO THE WRN GREAT LAKES. AS THE SFC LOW TRACKS FROM WRN MN SUNDAY MORNING TO THE SE END OF LAKE SUPERIOR EARLY MON MORNING...DEEP LAYER QVECTOR CONV AND 285K-295K ISENTROPIC LIFT WILL SUPPORT AN AREA OF PCPN MOVING INTO SW UPPER MI SUN AFTERNOON AND ACROSS THE CWA SUN NIGHT. PCPN AMOUNTS IN THE 0.25 TO 0.50 INCH RANGE ARE EXPECTED. MODEL FCST SOUNDINGS...AND WET-BULB ZERO HEIGHTS SUPPORT THE POTENTIAL FOR A SOME SNOW ACCUMULATION OVER THE HIGHER TERRAIN OF THE WEST HALF OF UPPER MI. WITH ONLY LIGHT TO MODERATE SNOWFALL RATES EXPECTED...AND RELATIVELY LOW SNOW/WATER RATIO VALUES BELOW 10/1...ANY SNOW ACCUMULATION SHOULD GENERALLY REMAIN AT OR BELOW 2 INCHES. THERE MAY ALSO BE SOME ADDITIONAL LAKE ENHANCED SNOW INTO NW UPPER MI LATE AS WNW WINDS STRENGTHEN BEHIND THE LOW. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 337 AM EDT SUN OCT 20 2013 AN ACTIVE WEATHER PATTERN IS IN STORE FOR THE UPPER GREAT LAKES REGION FOR THE UPCOMING WORK WEEK. THE UPPER TROUGH THAT IS AFFECTING THE UPPER GREAT LAKES WILL BE RE-ENFORCED BY A SHORTWAVE CURRENTLY DROPPING SOUTH OVER LAKE WINNIPEG. THIS WAVE WILL CATCH UP WITH THE SURFACE LOW AND SHORTWAVE IN SOUTHERN MINNESOTA (CURRENTLY IN WESTERN NORTH DAKOTA) AND INTENSIFY THE LOW TONIGHT AS THE SHORTWAVES PHASE...CAUSING THE LOW TO LIFT NORTHEAST AND OVER EASTERN LAKE SUPERIOR BY 12Z MONDAY. MODELS SEEM TO BE COMING INTO BETTER AGREEMENT ON THE TRACK/INTENSITY OF THE LOW AS IT MOVES NORTH FROM EASTERN LAKE SUPERIOR ON MONDAY...WHILE LEAVING A SURFACE TROUGH BACK OVER THE LAKE THROUGH MONDAY NIGHT. EXPECT THE INITIAL SURGE OF PRECIPITATION THAT MOVES THROUGH SUNDAY AFTERNOON/NIGHT TO BE PUSHING NORTHEAST OF UPPER MICHIGAN. THUS...WITH COLD AIR SURGING EAST ACROSS UPPER MICHIGAN UNDER THE GUSTY WESTERLY FLOW...EXPECT THE MAIN WEATHER TO START MONDAY TO BE WESTERLY WIND LAKE ENHANCED PRECIPITATION. THIS IS DUE TO 850MB TEMPS FALLING TO -8C OVER WESTERN UPPER MICHIGAN BY 18Z MONDAY. WILL HIGHLIGHT THE HIGHEST POPS OVER THE HIGHER TERRAIN FROM THE KEWEENAW THROUGH THE GOGEBIC RANGE AND ALSO OVER THE HURON MOUNTAINS. WESTERLY WINDS LOOK TO BACK SLIGHTLY IN THE AFTERNOON AHEAD OF TROUGH DROPPING SOUTH ACROSS WESTERN LAKE SUPERIOR DURING THE LATE AFTERNOON. THIS MAY CAUSE THE BEST PRECIPITATION TO BE FOCUSED MORE OVER THE KEWEENAW DURING THE AFTERNOON. THEREFORE...DID OPT TO TRIM POP/QPF AMOUNTS OVER GOGEBIC/ONTONAGON COUNTIES SOME DURING THE AFTERNOON HOURS. SINCE WETBULB ZERO VALUES FALL OVER THE WEST AS THE COLD AIR SURGES EAST ACROSS THE U.P. EXPECT PRECIP TO FALL AS SNOW OVER THE WEST...BUT COULD MIX WITH RAIN AT TIMES NEAR LAKE SUPERIOR. SNOWFALL AMOUNTS DURING THE MORNING AND MOST OF THE AFTERNOON SHOULD BE LIGHT...WITH LOCATIONS SEEING AMOUNTS UNDER AN INCH. OVER THE REST OF UPPER MICHIGAN DURING THIS PERIOD...EXPECT BREEZY WESTERLY WINDS AND CLOUDY CONDITIONS...BUT LITTLE TO NO PRECIPITATION IS EXPECTED. THE BEST OPPORTUNITY WOULD BE OVER THE EAST RIGHT ALONG THE LAKE SUPERIOR/MICHIGAN SHORELINES AS LAKE ENHANCED PRECIPITATION WILL TRY TO PARALLEL THOSE AREAS. THEN TOWARDS SUNSET...THE SURFACE TROUGH WILL DROP SOUTH ONTO THE WESTERN U.P. SHORELINE AND BRING AN ENHANCED AREA OF CONVERGENCE AND PRECIPITATION. EXPECT THERE TO BE MODERATE TO HEAVY PRECIPITATION AS THIS TROUGH SLIDES THROUGH THE WESTERN U.P. DURING THE EVENING HOURS AND THEN THROUGH CENTRAL UPPER MICHIGAN DURING THE OVERNIGHT HOURS. 850MB TEMPS WILL ACTUALLY WARM A COUPLE DEGREES BEHIND THE TROUGH...BUT THE DEEP MOISTURE AND CYCLONIC FLOW ON THE BACK SIDE OF THE SURFACE AND 850MB LOW...ALONG WITH UPSLOPE WINDS...WILL SUPPORT LAKE ENHANCED PRECIPITATION THROUGH A GOOD PORTION OF THE NIGHT OVER THE WESTERN CWA AND INTO TUESDAY MORNING OVER THE NORTH CENTRAL CWA. THE PRECIPITATION DURING THIS PERIOD SHOULD FALL AS SNOW EXCEPT FOR LOCATIONS RIGHT ALONG THE LAKE SUPERIOR SHORELINE WHERE THE NORTH-NORTHWEST WINDS WOULD PRODUCE SOME HEAT TRANSFER FROM THE LAKE AND LEAD TO SOME RAIN/SNOW MIX. AS FOR RATIOS/AMOUNTS...THINKING THE SNOW RATIOS WILL BE AROUND OR JUST BELOW 10-1 WITH THE BEST FORCING BEING BELOW THE DGZ AND SNOW FLAKES FALLING FROM ALOFT CLUMPING TOGETHER AS THEY REACH THE STRONG UPWARD MOTION NEAR THE SURFACE. AS FOR QPF AMOUNTS...HPC INDICATES NAM IS THE COLDER SOLUTION IN THE MID LEVELS (BY AROUND 2C) BEHIND THE LOW...WHICH MAY BE PART OF THE REASON IT IS MUCH HIGHER ON QPF AMOUNTS WITH THE LAKE ENHANCED SNOW BEHIND THE TROUGH. SINCE THE HIGHER RESOLUTION OF THE NAM AND 4KM NEST PICK UP THE TERRAIN ENHANCEMENT...DID BLEND THAT WITH THE PREFERRED WARMER AND COARSER MODELS FOR QPF MONDAY AFTERNOON THROUGH TUESDAY MORNING. THIS CREATES 24HR VALUES OF 0.5-0.75IN FROM IRONWOOD THROUGH THE KEWEENAW AND ALSO OVER THE WESTERN SIDE OF THE HURON MOUNTAINS. AT 10-1 SLR VALUE...SNOWFALL AMOUNTS IN THE 3-6 INCH RANGE SEEM REASONABLE IN THOSE AREAS AFTER FACTORING SOME MELTING INITIALLY ON MONDAY WHEN THE SNOWFALL RATES ARE LIGHTER. THAT SEEMS TO FIT IN WITH OUR ADVISORY CRITERIA AND WILL LIKELY END UP JUST UNDER THE 6INCH IN 12HR MARK FOR WARNINGS. CIPS TOP ANALOGS (BASED OFF THE SLIGHTLY COLDER NAM SOLUTION) SHOW MEAN SNOWFALL AMOUNTS OF 4-8 INCHES OF A 72HR PERIOD AND PROBABILITIES OF SEEING 6IN OF SNOW AROUND 60 PERCENT. THINK THE FORECAST MATCHES UP PRETTY WELL WITH THAT IDEA (ALONG WITH HPC GUIDANCE) AND WILL CONTINUE TO HIGHLIGHT THIS MEASUREABLE SNOW EVENT IN THE HWO AND ISSUE AN SPS TO HIGHTEN THE AWARENESS. SURFACE TROUGH WILL QUICKLY SHIFT EAST OF THE AREA ON TUESDAY...AS AN AREA OF HIGH PRESSURE SLIDES INTO THE NORTHERN PLAINS. EXPECT A DIMINISHING PRECIPITATION TREND FROM WEST TO EAST ACROSS THE CWA WITH THE DEEPER MOISTURE DEPARTING. THROUGH THE REST OF THE WEEK...EXPECT NORTHWESTERLY FLOW TO BE IN PLACE AS THE LOW SITS OVER QUEBEC AND A SERIES OF HIGHS DROP SOUTHEAST THROUGH THE NORTHERN PLAINS. 850MB TEMPS THROUGH THE REST OF THE PERIOD SHOULD BE RIGHT AROUND -8C WHICH LEADS TO PLENTY OF LAKE INSTABILITY. WILL CONTINUE TO HIGHLIGHT CHANCE POPS OR HIGHER IN THE TRADITIONAL NORTHWEST FLOW LOCATIONS THROUGH FRIDAY. HIGHEST POPS AND POTENTIAL FOR ACCUMULATION SNOWFALL WILL BE OVER THE EASTERN U.P. WITH THE LONGER FETCH AND CLOSER PROXIMITY TO THE BETTER MOISTURE UNDER THE UPPER LOW. THERE WILL BE A COUPLE BRIEF PERIODS WHERE THE LAKE EFFECT PRECIPITATION WILL PICKUP AS WEAK SHORTWAVES AND BETTER MOISTURE SWEEP THROUGH. CIPS TOP ANALOGS FOR THE MID WEEK PERIOD UNDER PERSISTENT LAKE EFFECT SNOWFALL SHOWS PROBABILITY FOR 4IN OF SNOW IN A 72HR PERIOD BEING AROUND 60 PERCENT IN THE TRADITIONAL FAVORED NORTHWEST FLOW LOCATIONS. BEING THAT IS OVER A 3 DAY PERIOD...THING THOSE VALUES ARE REASONABLE WITH LIGHT ACCUMULATIONS OCCURRING THROUGH THE END OF THE WORK WEEK. THE UPPER TROUGHS INFLUENCE ON THE UPPER GREAT LAKES LOOKS TO WEAKEN THIS WEEKEND AS IT SHIFTS EAST INTO THE NEW ENGLAND STATES. BUT ANOTHER SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE ROCKIES WILL TRY TO MOVE INTO THE AREA FOR THE SECOND HALF OF THE WEEKEND. WILL JUST GO WITH A GENERAL CONSENSUS AND HAVE CHANCE POPS WITH TEMPERATURES REMAINING BELOW NORMAL. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 242 PM EDT SUN OCT 20 2013 TIMING OF THE APPROACHING SNOW AND LOWER CEILINGS HAS BEEN VERY TRICKY TODAY...MADE TRICKIER BY FOG/STRATUS THIS MORNING ACROSS THE HIGHER ELEVATIONS OF THE W HALF OF UPPER MI. THIS MAINLY INFLUENCED SAW...WHICH WAS RIGHT ON THE CLEARING LINE THANKS TO LIGHT DOWNSLOPE WINDS MUCH OF THE MORNING. CEILINGS HAVE BEEN HOVERING BETWEEN HIGH END MVFR AND VFR EARLY THIS AFTERNOON...WITH THE RAIN/SNOW LINE AND MVFR TO IFR CEILINGS NEARING FROM N CENTRAL WI THIS AFTERNOON. EXPECT DETERIORATING CONDITIONS AT ALL 3 SITES...WITH RAIN SLOWLY MIXING WITH SNOW OVERNIGHT. THE MIX OF RAIN AND SNOW WILL LIKELY CHANGE OVER TO ALL SNOW AT IWD SHORTLY BEFORE DAYBREAK AS COOLER AIR RUSHES IN ON FAVORABLE W-NW WINDS. THE CHANGE OVER SHOULD TAKE A COUPLE MORE HOURS AT CMX...WITH A LOW TEMP IN THE MID 30S OVERNIGHT. STRONGER W WINDS WILL BE COMMON STARTING 09-15Z W TO E...WITH GUSTS OF 25-30KTS /STRONGEST AT CMX/...AS CEILINGS SLOWLY IMPROVE AS THE BULK OF THE MOISTURE EXITS AS THE SFC LOW PUSHES INTO E QUEBEC. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT SUN OCT 20 2013 LOW PRESSURE MOVEING OUT OF THE DAKOTAS WILL BEGIN TO INTENSIFY OVER THE UPPER MISSISSIPPI VALLEY TODAY AND THEN MOVE THROUGH THE UPPER GREAT LAKES TONIGHT AND MONDAY. AS THIS OCCURS...WINDS WILL STRENGTHEN ACROSS THE LAKE...FIRST OUT OF THE SOUTH TO SOUTHEAST AHEAD OF THE LOW THIS EVENING AND THEN OUT OF THE WEST BEHIND THE LOW LATE TONIGHT INTO MONDAY. THERE STILL ARE SOME DIFFERENCES IN THE EXACT TRACK AND STRENGTH OF THE LOW AS IT MOVES ACROSS LAKE SUPERIOR ON MONDAY...SO WIND SPEED/DIRECTIONS ARE STILL UNCERTAIN. AT THIS TIME...IT APPEARS THE STRONGEST WINDS WILL BE BEHIND THE LOW ON MONDAY AND MONDAY NIGHT...WHEN WEST GALES TO 35-40KTS VEERING TO THE NORTH ARE EXPECTED. ONCE THE LOW DEPARTS THE AREA...EXPECT NORTHWESTERLY WINDS UP TO 25KTS TO REMAIN OVER LAKE SUPERIOR INTO WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY AFTERNOON FOR LSZ265>267. GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR LSZ264. GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...KF MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
202 PM EDT SUN OCT 20 2013 .SYNOPSIS... ISSUED AT 335 AM EDT SUN OCT 20 2013 COOL WEATHER WITH PERIODS OF LAKE EFFECT SHOWERS WILL CONTINUE INTO NEXT WEEK...AS A BROAD TROUGH OF LOW PRESSURE REMAINS OVER THE GREAT LAKES. EVEN COLDER AIR WILL ENGULF THE GREAT LAKES AND UPPER MIDWEST BY MONDAY...AS ANOTHER WEAK STORM SYSTEM EXITS NORTHEAST INTO QUEBEC EARLY IN THE WORK WEEK. TEMPERATURES MAY GET COLD ENOUGH TO BRING THE FIRST SNOWFALL OF THE SEASON...ESPECIALLY TO INTERIOR SECTIONS OF EASTERN UPPER AND NORTHERN LOWER MICHIGAN. && .UPDATE... ISSUED AT 201 PM EDT SUN OCT 20 2013 SCT-BKN STCU DECK HAS EXPANDED ACROSS THE CWA OVER THE LAST FEW HOURS...LEADING TO PARTLY SUNNY SKIES FOR MOST AREAS. REMAINING SMALL BATCH OF LAKE INDUCED SHOWERS CONTINUES TO WORK UP THROUGH THE STRAITS INTO EASTERN UPPER MICHIGAN...AS ANTICIPATED. BUT DRY WEATHER ELSEWHERE. UPSTREAM...SFC LOW PRESSURE SLIDING SOUTHEASTWARD THROUGH THE UPPER MIDWEST IN RESPONSE TO SMALL UPPER JET CORE PUSHING ACROSS IOWA...AND SUBSTANTIALLY STRONGER SHORT WAVE ENERGY DIVING SOUTHWARD OUT OF SOUTH-CENTRAL CANADA. INCREASING WARM ADVECTION AHEAD OF THE LOW ALREADY PUSHING A BAND OF PRECIP THROUGH WISCONSIN. THIS BATCH OF WARM ADVECTION FORCED PRECIP WILL PIVOT SW-NE UP INTO NRN MICHIGAN OVER THE NEXT FEW HOURS LEADING TO A PERIOD RAINFALL ACROSS THE CWA THIS EVENING. MAIN PERIOD OF RAINFALL LOOKING TO OCCUR BETWEEN 00Z AND 06Z AS SUBSTANTIALLY WARM AIR SURGES UP INTO NRN MICHIGAN. WILL CATCH A BIT OF A BREAK DURING THE OVERNIGHT HOURS BEFORE STRONG SHORT WAVE DRIVES ACROSS NRN MICHIGAN LATE OVERNIGHT THROUGH MONDAY MORNING...AND WRAP AROUND MOISTURE/COLDER AIR ROTATE INTO THE REGION. TRANSITION DAY ON MONDAY. UPDATE ISSUED AT 1036 AM EDT SUN OCT 20 2013 GOT A BIT OF A BREAK DURING THE OVERNIGHT HOURS WITH CLOUDS THINNING/ CLEARING OUT OVER A GOOD PART OF CWA...WELL DOWNWIND OF THE LAKES. BUT MEANWHILE...LAKE AGGREGATE TROUGH ANALYZED FROM WESTERN LAKE SUPERIOR DOWN INTO NRN LAKE MICHIGAN THIS MORNING. MESOSCALE SFC LOW HAS DEVELOPED OVER NRN LAKE MICHIGAN GIVEN THE WEAKER SYNOPTIC WIND REGIME/SHORELINE ORIENTATION AND OFFSHORE WIND COMPONENT. A FEW POCKETS OF LAKE INDUCED SHOWERS LINGER WITHIN THIS FEATURE ACROSS NRN LAKE MICHIGAN (CAN SEE THE LOW LEVEL SPIN IN THE RADAR DATA...PUSHING UP INTO PARTS OF NW LOWER INTO THE STRAITS AND EASTERN UPPER. REST OF TODAY...POTENT SHORT WAVE AND POCKET OF COLDEST AIR OF THE SEASON ON TRACK TO DROP INTO THE UPPER MIDWEST...THAT WILL ULTIMATELY DRIVE A DEEPENING SFC LOW/POTENT COLD FRONT THROUGH THE REGION...LATE TONIGHT AND MONDAY MORNING. AHEAD OF THIS DEVELOPING SYSTEM...LOW LEVEL FLOW WILL BACK MORE SOUTHERLY AS WE GO THROUGH THE AFTERNOON...PUSHING REMAINING LAKE INDUCED SHOWERS UP THROUGH EASTERN UPPER MICHIGAN. PULSE OF LOW-MID LEVEL WARM ADVECTION FORCING AHEAD OF THAT DEVELOPING SYSTEM ALREADY PRODUCING A BAND OF PRECIP EXPANDING INTO WESTERN WISCONSIN THIS MORNING. FORCING LOOKING TO DEVELOP INTO THE W/SW PART OF THE CWA BY LATE AFTERNOON. GOING FORECAST ALREADY HAS CHANCY POPS OVER THE SW COUNTIES AND A SLIVER OF EASTERN UPPER MICHIGAN...WHICH LOOKS FINE FOR NOW. HAVE TWEAKED SKY FORECASTS FOR THE BALANCE OF THE DAY BASED ON TRENDS...TO HAVE A LITTLE MORE SUNSHINE THROUGH MIDDAY. ALSO TWEAKED TEMP CURVE FOR TONIGHT. BIG SURGE OF WARM AIR ALOFT AND INCREASING SOUTHERLY WINDS SHOULD ACTUALLY RESULT IN FLAT LINE OR EVEN WARMING TEMPS TONIGHT. JUST HOW WARM DEPENDS ON HOW FAR NORTH THE SFC WARM FRONT CAN GET...BUT CAN ENVISION SOME LOCATIONS PUSHING THE HIGH 40S TO NEAR 50 OVERNIGHT...BEFORE IT ALL CRASHES ON MONDAY WITH FROPA. UPDATE ISSUED AT 657 AM EDT SUN OCT 20 2013 CLOUDS HAVE OPENED UP CONSIDERABLY IN PARTS OF NE LOWER AND EASTERN UPPER MI. THIS WILL TEND TO SELF-DESTRUCT WITH HEATING TODAY...THE SUB-800MB AIRMASS REMAINS ON THE MOIST SIDE. SOME ADJUSTMENTS MADE TO EARLY-MORNING CLOUD COVER. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 335 AM EDT SUN OCT 20 2013 MUCH DISCUSSED DEEP TROUGHING CONTINUES TO DOMINATE GREAT LAKES WEATHER AT THIS EARLY HOUR...DOWNSTREAM OF EQUALLY IMPRESSIVE RIDGING POCKING UP AND BEYOND THE NORTHWEST TERRITORIES. SUBTLE WAVE TRAVERSING WITHIN THIS FLOW...NOW IN THE PROCESS OF FURTHER DEAMPLIFYING AND CUTTING ACROSS THE NORTHERN LAKES. THIS...COMBINED WITH STILL MORE THAN SUPPORTIVE OVER-WATER INSTABILITY (H8 TEMPERATURES RIGHT AROUND -2C PER HIGH RES RAP AND 00Z SOUNDING ANALYSIS)...CONTINUES TO KICK OFF LAKE ENHANCED RAIN SHOWERS OFF NORTHERN LAKE MICHIGAN (EVEN HAD SOME LEGITIMATE SNOWFLAKES MIX IN WITH THE RAIN HERE ON TOP OF THE HILL). OTHERWISE...A RATHER QUIET AND TOUCH CHILLY NIGHT...WITH CURRENT READINGS MAINLY IN THE 30S AND LOWER 40S. MAIN SYSTEM OF INTEREST THROUGH THE SHORT TERM IS WELL DEFINED SHORTWAVE/VORT LOBE DROPPING STRAIGHT SOUTH THROUGH CENTRAL MANITOBA. THIS SYSTEM WILL DRUM UP A RATHER RESPECTABLE AREA OF LOW PRESSURE TONIGHT AS IT DROPS INTO MINNESOTA. GOOD MID LEVEL SUPPORT AND LOW LEVEL ENERGY SUPPLIED BY WARM LAKE WATERS WILL HELP DEEPEN THIS SURFACE LOW AS IT MOVES UP INTO EASTERN LAKE SUPERIOR BY MONDAY MORNING. THIS SYSTEM WILL BRING MORE WIDESPREAD RAINS HEADING INTO TONIGHT...AND PERHAPS A GALE EVENT ON PARTS OF THE BIG WATERS. SHORT TERM FORECAST CONCERNS CENTER ON ADDRESSING THE IMPACTS OF THIS SYSTEM. BY AND LARGE...A RATHER NON-EVENTFUL WEATHER DAY EXPECTED TODAY. CURRENT OVERHEAD WAVE WILL HAVE EXITED STAGE RIGHT BY SUNRISE...LEAVING PURE LAKE PROCESSES FOR ANY ADDITIONAL SHOWER DEVELOPMENT THROUGH MID AFTERNOON. EXPECT THERE WILL BE SOME ONGOING TO START THE DAY...ESPECIALLY ALONG THE NORTHWEST LOWER COASTLINE WHERE WIND CONVERGENCE WILL BE MAXIMIZED. LAKE PROCESSES WILL BE A DOWNWARD ONE HEADING THROUGH THE DAY AS WINDS BACK SOUTHERLY AND WEAK MID LEVEL RIDGING BUILDS OVERHEAD. ATTENTION LATE THIS AFTERNOON INTO THE OVERNIGHT TURNS TO STRONG WAA RESPONSE AHEAD OF EARLIER MENTIONED DEEPENING SURFACE LOW. RATHER IMPRESSIVE ISENTROPIC UPGLIDE SIGNATURE VIA FORCED ASCENT ON NOSE OF 40+ KNOT LOW LEVEL JET...WITH WELL OVER HALF INCH PWATS ALSO SURGING NORTH INTO THE AREA WITH THIS JET. ABOVE LOOKS TO KICK OFF A RATHER LARGE AREA OF RAIN...WHICH WILL SPREAD RAPIDLY NORTHEAST ACROSS OUR AREA LATE THIS AFTERNOON INTO THIS EVENING. PER FULL 00Z GUIDANCE ANALYSIS...MAY AMP UP RAIN CHANCES SOME SOUTHWEST THIRD OF THE AREA AFTER 21Z TODAY...WITH INHERITED CATEGORICAL WORDING INTO THIS EVENING LOOKING GREAT. DRY SLOT PUNCHES IN FROM THE SOUTHWEST THROUGH THE OVERNIGHT...LIKELY ABRUPTLY ENDING RAINS AS IT DOES SO. MAY SEE SOME LAKE SHOWERS ATTEMPT TO FIRE FAR NORTHERN LAKE MICHIGAN TOWARDS MORNING WHERE MOISTURE WILL REMAIN DEEPER AND POST-COLD FRONT CAA REGIME ONCE AGAIN DROPS H8 READINGS TO JUST BELOW 0C. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 335 AM EDT SUN OCT 20 2013 CLASSIC LATE AUTUMN WX WILL REMAIN IN PLACE FOR THE UPCOMING WEEK...A BIT AHEAD OF SCHEDULE. PLENTY OF UPPER TROFFING WILL REMAIN IN PLACE IN CENTRAL CANADA AND ADJOINING PARTS OF THE STATES. THE LOWEST HEIGHTS WILL BE OVERHEAD MONDAY EVENING...AS AN UPPER LOW CROSSES EASTERN SUPERIOR. HOWEVER...HEIGHT RECOVERY AFTER THAT LOW EJECTS TO THE NE WILL BE ANEMIC. THAT WILL MAINTAIN MIXED PRECIP AS A SIGNIFICANT FORECAST CONCERN...ESPECIALLY DURING THE LATE NIGHT/ EARLY MORNING HOURS. PRECIP TRENDS ARE THE MAIN CONCERN. MONDAY...500MB LOW MOVES FROM INL TO MQT. 999MB SURFACE LOW OVER EASTERN SUPERIOR WILL LIFT NE TO SSW OF JAMES BAY...WITH A NEW LOW SPINNING UP ALONG A SECONDARY COLD FRONT IN CENTRAL SUPERIOR DURING THE AFTERNOON. THE BACK EDGE OF THE WARM CONVEYOR BELT WILL BE ABOUT TO EXIT NE LOWER MI AT 12Z...WITH DRIER MID LEVEL AIR IN THE PROCESS OF POURING INTO NORTHERN LOWER. HOWEVER...OVERLAKE INSTABILITY WILL BE INCREASING CONSIDERABLY AS COLDER LOW LEVEL AIR POURS IN. 850MB TEMPS OVER NORTHERN LAKE MI WILL NEAR -6C BY 18Z...-8C BY 00Z. MEANWHILE...EASTERN UPPER WILL REMAIN ON THE SOUTHERN PERIPHERY OF THE DEEPER WRAPAROUND MOISTURE. COULD STILL BE SOME FRONTAL SHRA IN FAR EASTERN SECTIONS TO START THE MORNING. SCT SHRA WILL GET GOING IN WSW-FLOW AREAS (ESPECIALLY FROM LEELANAU NORTHWARD) DURING THE MORNING...AS WELL AS IN EASTERN UPPER. THESE COULD BECOME MORE NUMEROUS IN THE AFTERNOON...AS INSTABILITY INCREASES (DELTA T/S IN THE LOWER 20S) AND THE CORE OF THE DRY SLOT MOVES EAST. 1000-850MB WINDS WILL VEER TO THE WEST DURING THE AFTERNOON...WITH INVERSION HEIGHTS A REASONABLY HEALTHY 6-7K FT. WILL INTRODUCE A SMALL CHANCE FOR A MIX VERY LATE IN THE DAY IN THE INTERIOR OF EASTERN UPPER...WHERE THE SURFACE-BASED MELTING LAYER IS NARROWING BELOW 1K FT. MAX TEMPS IN THE 40S (TO LOWER 50S NE LOWER) AND EARLY...WITH FALLING TEMPS IN THE PM. BRISK TO WINDY...ESPECIALLY NEAR LAKE MI. MON NIGHT/TUESDAY...UPPER LOW WILL GRADUALLY LIFT OUT TOWARD JAMES BAY...THOUGH WITH A SUBSTANTIAL SHORTWAVE ROUNDING IT/S SOUTHERN FLANK LATE MONDAY NIGHT. THAT WILL DRIVE THE SECONDARY FRONT INTO EASTERN UPPER MI LATE MONDAY NIGHT...AND ACROSS THE REST OF THE FORECAST AREA ON TUESDAY. 1000-850MB WINDS WILL BRIEFLY BACK MORE WSW AGAIN JUST AHEAD OF THIS TROF...ALLOWING THE INITIAL 850MB THERMAL TROF TO MOVE EAST AND BOOSTING 850MB TEMPS TO -5C. WINDS RAPIDLY VEER NW BEHIND THE TROF...AND COLD ADVECTION RESUMES. AFTER CONTINUED LOW-END-ISH LAKE EFFECT MONDAY EVENING (THOUGH WITH MORE SNOW MIXING IN AS DIURNAL HEATING IS LOST)...PRECIP WILL SUBSTANTIALLY RAMP UP OVERNIGHT AS THE SECONDARY FRONT AND SHARP 1000-850MB CONVERGENCE ARRIVES. SLUSHY ACCUMS UP TO AN INCH SEEM A DISTINCT POSSIBILITY MONDAY NIGHT NEAR GLR/BOYNE CITY/MANCELONA... AND IN WESTERN CHIP. TUESDAY WILL SEE A WOBBLY NW FLOW...BUT WITH MID-LEVEL DRYING/SUBSIDENCE AS THE VORT LOBE MOVES EAST. SOME LAKE EFFECT WILL CONTINUE...ESPECIALLY IN THE MORNING...WITH DISRUPTIVE DIURNAL HEATING DISORGANIZING THINGS IN THE PM. SOME SLOPPY LIGHT ACCUMS ARE AGAIN POSSIBLE IN THE MOST FAVORED AREAS OF BOTH PENINSULAS IN THE MORNING. MIN TEMPS WITHIN A FEW DEGREES OF 30F. MAX TEMPS NEAR 40F TO THE MID 40S. AND IT WILL REMAIN BRISK TO WINDY. REST OF THE FORECAST...FEW CHANGES NEEDED...AS COLD AND SHOWERY WX WILL PERSIST AS CURRENTLY FORECAST. NEW ECMWF IS FLAT-OUT COLD STRAIGHT THRU 240HRS. (PROBABLY BEST FOR MOTHER NATURE TO GET THIS OUT OF HER SYSTEM NOW.) && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 201 PM EDT SUN OCT 20 2013 VFR CONDITIONS ANTICIPATED THROUGH THE BALANCE OF THE AFTERNOON HOURS WITH SCT-BKN CLOUDS. LOW PRESSURE OVER THE UPPER MIDWEST WINDS UP THIS AFTERNOON BEFORE SWINGING UP THROUGH THE REGION TONIGHT. SURGE OF WARM AIR AND RESULTING RAINFALL ARRIVES EARLY THIS EVENING AHEAD OF THE LOW...LOWERING CIGS/VSBYS TO MVFR FOR MUCH OF THE EVENING HOURS. LOW LEVEL WIND SHEAR ALSO A GOOD BET THIS EVENING AS LOW LEVEL WINDS RAMP UP. MAIN BATCH OF RAINFALL EXITS QUICKLY OVERNIGHT...AFTER 06Z...BUT WITH VFR CIGS PERSISTING THROUGH THE BALANCE OF THE NIGHT. COLD FRONT SWEEPS THROUGH MONDAY MORNING LEADING TO GUSTIER WESTERLY WINDS THROUGH MONDAY. MVFR CIGS PERSIST WITH SHOWERS NEAR LAKE MICHIGAN. && .MARINE... ISSUED AT 335 AM EDT SUN OCT 20 2013 RELATIVELY LIGHT WINDS THIS MORNING GIVES WAY TO INCREASINGLY GUSTY SOUTH FLOW LATER THIS AFTERNOON...AND ESPECIALLY TONIGHT...AS LOW PRESSURE INTENSIFIES AND PUSHES INTO EASTERN LAKE SUPERIOR BY MONDAY MORNING. TIGHTENING PRESSURE GRADIENT AND ONSET OF IMPRESSIVE SURGE OF CAA WILL LEAD TO VERY GUSTY WEST TO SOUTHWEST WINDS DURING THE DAY MONDAY...WITH THE STRONGEST WINDS EXPECTED OVER NORTHERN LAKE MICHIGAN. GALE FORCE WIND GUSTS APPEAR INCREASINGLY LIKELY...RESULTING IN AN UPGRADE TO INHERITED NORTHERN LAKE MICHIGAN GALE WATCH TO A WARNING. IN ADDITION...WIND GUST MAY REACH GALE FORCE ACROSS WHITEFISH BAY AND THE ST. MARYS RIVER LATER MONDAY MORNING THROUGH THE AFTERNOON. CONFIDENCE NOT HIGH ENOUGH TO WARRANT A GALE WARNING...BUT ENOUGH CONCERN TO HOIST A GALE WATCH FOR THESE AREAS. ADDITIONAL SCA/S WILL LIKELY BE NEEDED FOR OTHER NEARSHORE ZONES...BUT WILL FOCUS ON GALE CONDITIONS AND PUNT ADVISORY ISSUANCES TO FUTURE FORECAST SHIFTS. WELCOME TO FALL ON THE GREAT LAKES! && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LHZ345. LM...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LMZ341- 342-344>346. LS...GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ321- 322. && $$ UPDATE...BA SYNOPSIS...JZ SHORT TERM...MB LONG TERM...JZ AVIATION...BA MARINE...MB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
146 PM EDT SUN OCT 20 2013 LATEST UPDATE... AVIATION .SYNOPSIS... ISSUED AT 344 AM EDT SUN OCT 20 2013 INTERVALS OF SHOWERS WILL CONTINUE THROUGH THE MAJORITY OF THE WEEK THIS WEEK AS A STRONG SURGE OF COLD CANADIAN AIR TAKES HOLD OF THE AREA. WAVES OF LOW PRESSURE WILL COMBINE WITH LAKE EFFECT TO BRING THE OCCASIONAL SHOWERS TO THE AREA. COLD ENOUGH AIR IS EXPECTED TO MOVE IN TO ALLOW FOR SOME SNOW TO MIX IN AT TIMES WITH THE RAIN SHOWERS. HIGHS WILL LIKELY REMAIN ONLY IN THE 40S MANY TIMES THIS WEEK. && .UPDATE... ISSUED AT 1205 PM EDT SUN OCT 20 2013 I ADDED THUNDERSTORMS TO OUR ZONE FORECASTS TONIGHT. AFTER LOOKING AT THE 1000 J/KG OF MOST UNSTABLE CAPE OVER LAKE MICHIGAN EARLY THIS EVENING. RAP AND NAM SOUNDINGS THIS EVENING INTO THE OVERNIGHT SHOW NO INVERSION TO CAPE THE INSTABILITY...WHICH IS UNLIKE LAST NIGHT WHEN WE HAD THUNDERSTORMS BUT THE INSTABILITY WAS CAPED AROUND 120000 FT. THE SOUNDINGS GIVE EQUILIBRIUM LEVELS AS HIGH AS 350000 FT THIS EVENING. THE CAPE IS SKINNY...BUT GIVEN THE 50 KNOT LOW LEVEL JET THAT POKES INTO OUR SOUTHWEST CWA BETWEEN 8 PM AND 11 PM... PLUS OUR AREA BEING IN THE EXIT REGION OF THE POLAR JET TONIGHT. THE NAM THUNDERSTORMS PROBABILITY PROG HAS NUMBERS AS HIGH AS 60 PCT OVER LAKE MICHIGAN AND 40 PCT INLAND NORTH OF HOLLAND TO US-131 JUST BEFORE MIDNIGHT. THE SPC 03Z SREF ALSO FORECASTS THUNDERSTORMS OVER LAKE MICHIGAN INTO SOUTHWEST LOWER MICHIGAN SIMILAR TO THE NAM THUNDERSTORM PROP CHART. ALL OF THIS TELLS ME WE SHOULD SEE THUNDERSTORMS DEVELOPING OVER LAKE MICHIGAN EARLY TONIGHT THEY WILL THEN MOVE INLAND DURING THE MID EVENING HOURS JUST AHEAD OF THE COLD FRONT. DUE TO THE SOUTHWEST WINDS THE BEST INSTABILITY (AIDED BY THE WARMTH OF LAKE MICHIGAN) WILL MOSTLY BE NORTH OF A LINE FROM HOLLAND TO ALMA. I ALSO INCREASED THE POP TONIGHT SINCE THERE IS LITTLE QUESTION GIVEN THE WARM LAKE AND DYNAMICS PLUS A DECENT SHOT AT DEEP MOISTURE THAT THERE WILL BE SHOWERS TONIGHT. ANY STORMS MAY HAVE SMALL HAIL GIVEN THE FREEZING LEVEL BEING BELOW 7000 FT. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 344 AM EDT SUN OCT 20 2013 PCPN TRENDS AND TYPE ARE THE MAIN FOCUS OF THE FCST PACKAGE TODAY. THE SHOWER ACTIVITY THAT WAS WIDESPREAD ACROSS THE AREA LAST EVENING IS SCATTERING OUT AND DISSIPATING EARLY THIS MORNING. THIS IS DUE TO MAINLY THE UPPER FLOW TRANSITIONING TO ANTI-CYCLONIC AS THE LAST SHORT WAVE IN THIS SEQUENCE IS NOW LIFTING TO THE E/NE THIS MORNING. WE EXPECT THE SHOWER ACTIVITY TO PRETTY MUCH END FOR A FEW HOURS AS SHORT WAVE RIDGING BUILDS IN AND WE LOSE THE LOW LEVEL MOISTURE. SOME BREAKS IN THE CLOUDS WILL BE LIKELY ONCE AGAIN...HOWEVER JUST AS THE LOW LEVEL MOISTURE MOVES OUT...MID AND HIGH LEVEL MOISTURE FROM THE NEXT SYSTEM MOVES RIGHT IN. THE NEXT SYSTEM IN THE SEQUENCE WILL BE BRINGING PCPN TO THE FAR NW CORNER OF THE CWFA AS EARLY AS LATE THIS AFTERNOON. THIS WAVE IS CURRENTLY LOCATED NORTH OF LAKE WINNIPEG AND DROPPING SOUTHEAST QUICKLY. IT WILL MERGE WITH ANOTHER SHORT WAVE COMING INTO THE DAKOTAS. THE TRACK OF THE SHORT WAVE AND SFC LOW WILL FAVOR THE NRN SECTION OF THE CWFA FOR THE BEST PCPN CHCS. IT DOES LOOK LIKE THE ENTIRE CWFA WILL HAVE A CHC OF RAIN AS THE COLD FRONT PASSES THROUGH THE AREA VERY LATE TONIGHT AND MON MORNING. THE THREAT OF LAKE EFFECT RAIN SHOWERS WILL BE THERE ON MON WITH DELTA T/S EXPECTING TO BE AROUND 20C. THE THREAT DOES NOT LOOK TO BE VERY BIG HOWEVER AS THE DRY SLOT WILL AFFECT THE AREA BEHIND THE FRONT. MOISTURE PROFILES INDICATE THAT THEY WILL BE DEEP ENOUGH FOR SOME PCPN TO BE GENERATED AS THE DGZ WILL BARELY BE SATURATED. INVERSION HEIGHTS ARE SOMEWHAT LOW AS THE UPPER LOW AND CORE OF THE CYCLONIC FLOW STAYS MAINLY NORTH OF THE AREA. THE THREAT OF SHOWERS WILL CONTINUE TO BE POSSIBLE MON NIGHT AND EARLY TUE. THIS IS THE PERIOD WHEN IT LOOKS LIKE WE WILL SEE A POTENTIAL OF PCPN MIXING WITH OR CHANGING TO SNOW WITH H850 TEMPS DROPPING TO ALMOST -7C AND FREEZING LEVELS DROPPING BELOW 2000 FT. THE BEST POTENTIAL OF SEEING SOME SNOW WILL BE UP ACROSS CENTRAL LOWER MICHIGAN AT THE HIGHER ELEVATIONS. IN ADDITION TO THE POSSIBILITY OF SNOW...WE CAN NOT RULE OUT THUNDER ALONG THE LAKESHORE WITH LAKE MODIFIED PARCELS GENERATING OVER 1000 J/KG OF CAPE AND PARCELS REACHING TO -20C ISOTHERM. WATERSPOUTS WILL ALSO REMAIN POSSIBLE. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 344 AM EDT SUN OCT 20 2013 THERE SEEMS TO BE NO END IN SIGHT TO THE COOL AND UNSETTLED PATTERN AS DEEP UPPER TROUGHING PERSISTS OVER THE GREAT LAKES REGION THROUGH ALL OF NEXT WEEK. TEMPERATURES WILL AVERAGE AROUND 10 DEGREES BELOW NORMAL. H8 TEMPS ARE PROGGED TO REMAIN RIGHT AROUND -6C THROUGH MOST OF THE WEEK CREATING EXTREME LAKE INSTABILITY WITH DELTA T/S IN EXCESS OF 20C. OCCASIONAL SHORTWAVES PIVOTING THROUGH THE REGION WILL PERIODICALLY BOOST INVERSION HEIGHTS AND BRING SLUGS OF DEEPER MOISTURE THROUGH WHICH WILL ENHANCE THE SHOWER ACTIVITY. THE FREEZING LEVEL WILL BE AROUND 1500 FT SO WOULD EXPECT TO SEE A MIXTURE OF RAIN/SNOW/GRAUPEL... ESPECIALLY INLAND FROM WARMING EFFECTS OF LK MI INCLUDING THE HWY 131 CORRIDOR. SOME ACCUMULATING WET SNOW LOOKS TO BE A REALISTIC THREAT FOR WEDNESDAY THROUGH THURSDAY NIGHT WHEN BOTH THE GFS AND ECMWF INDICATE THAT WE WILL BE ON THE CYCLONIC SHEAR SIDE OF THE UPPER JET CORE WHICH WILL BE POSITIONED TO OUR WEST AND SOUTH. WARM ADVECTION IS CURRENTLY PROGGED FOR NEXT SATURDAY AHEAD OF A SYSTEM DROPPING DOWN FROM THE NORTHWEST. THIS WOULD END THE LAKE EFFECT TEMPORARILY BUT THE CHANCE OF RAIN WILL CONTINUE DUE TO ISENTROPIC LIFT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 146 PM EDT SUN OCT 20 2013 VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THIS EVENING EVEN THOUGH A FEW RAIN SHOWERS WILL BE MOVING IN. THERE IS THE OUTSIDE CHANCE THAT A THUNDERSTORM COULD MOVE THROUGH THE TAF SITES AFTER 00Z...BUT THESE ARE EXPECTED TO BE VERY ISOLATED AND THEY WERE NOT PUT IN THE TAFS AT THIS POINT. A STRONG COLD FRONT WILL APPROACH TOWARD DAYBREAK MON. THERE SHOULD BE A PERIOD OF MVFR AS THIS FRONT COMES THROUGH...ALONG WITH SCATTERED SHOWERS. THIS SHOULD IMPROVE TO VFR TOWARD MID DAY MON. WINDS WILL BE INCREASING THIS EVENING AND CONTINUE INTO MON AS THE FRONT COMES THROUGH. SSW WINDS AROUND 15 KTS WILL SHIFT TO THE WEST TOWARD DAYBREAK. PILOTS SHOULD ALSO KEEP IN MIND THE RISK OF IN-CLOUD ICING INTO MON. FREEZING LEVELS WILL BE DROPPING AFTER 12Z BEHIND THE COLD FRONT...TO 2K TO 3K FEET. CLOUD TOPS WILL BE AROUND 6K FEET. IN- CLOUD TEMPS WILL CONTINUE TO BECOME MORE FAVORABLE FOR ICING BEYOND 18Z MON. && .MARINE... ISSUED AT 1205 PM EDT SUN OCT 20 2013 I CONTINUED THE SMALL CRAFT ADVISORY INTO THIS EVENING AND THE GALE WARNING TONIGHT AND MONDAY. IT SEEMS TO ME THROUGH THAT THE WINDS WILL START TO DIMINISH MONDAY AFTERNOON. WE MAY BE ABLE TO DROP THE GALES BY MID AFTERNOON MONDAY. WATER SPOUTS WILL BE AN ISSUE ONCE THE WINDS DIMINISH BELOW GALES... SO I CONTINUED THE WATER SPOUTS IN THE NEAR SHORE FOR MONDAY NIGHT. && .HYDROLOGY... ISSUED AT 344 AM EDT SUN OCT 20 2013 WE ARE NOT ANTICIPATING ANY HYDROLOGY ISSUES IN THE NEXT WEEK. THE MAJORITY OF THE PCPN OVER THE NEXT WEEK WILL BE IN THE FORM OF SCATTERED SHOWERS. THIS TYPE OF PATTERN IS NOT CONDUCIVE FOR HEAVY RAINFALL WITH PRECIPITABLE WATERS RUNNING AROUND AVERAGE FOR THIS TIME OF YEAR. MOST LOCATIONS WILL NOT SEE PCPN OVER HALF AN INCH OVER THE NEXT FEW DAYS. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849. GALE WARNING FROM 8 PM THIS EVENING TO 5 AM EDT TUESDAY FOR LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...MEADE AVIATION...JK HYDROLOGY...NJJ MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1205 PM EDT SUN OCT 20 2013 LATEST UPDATE... UPDATE/MARINE .SYNOPSIS... ISSUED AT 344 AM EDT SUN OCT 20 2013 INTERVALS OF SHOWERS WILL CONTINUE THROUGH THE MAJORITY OF THE WEEK THIS WEEK AS A STRONG SURGE OF COLD CANADIAN AIR TAKES HOLD OF THE AREA. WAVES OF LOW PRESSURE WILL COMBINE WITH LAKE EFFECT TO BRING THE OCCASIONAL SHOWERS TO THE AREA. COLD ENOUGH AIR IS EXPECTED TO MOVE IN TO ALLOW FOR SOME SNOW TO MIX IN AT TIMES WITH THE RAIN SHOWERS. HIGHS WILL LIKELY REMAIN ONLY IN THE 40S MANY TIMES THIS WEEK. && .UPDATE... ISSUED AT 1205 PM EDT SUN OCT 20 2013 I ADDED THUNDERSTORMS TO OUR ZONE FORECASTS TONIGHT. AFTER LOOKING AT THE 1000 J/KG OF MOST UNSTABLE CAPE OVER LAKE MICHIGAN EARLY THIS EVENING. RAP AND NAM SOUNDINGS THIS EVENING INTO THE OVERNIGHT SHOW NO INVERSION TO CAPE THE INSTABILITY...WHICH IS UNLIKE LAST NIGHT WHEN WE HAD THUNDERSTORMS BUT THE INSTABILITY WAS CAPED AROUND 120000 FT. THE SOUNDINGS GIVE EQUILIBRIUM LEVELS AS HIGH AS 350000 FT THIS EVENING. THE CAPE IS SKINNY...BUT GIVEN THE 50 KNOT LOW LEVEL JET THAT POKES INTO OUR SOUTHWEST CWA BETWEEN 8 PM AND 11 PM... PLUS OUR AREA BEING IN THE EXIT REGION OF THE POLAR JET TONIGHT. THE NAM THUNDERSTORMS PROBABILITY PROG HAS NUMBERS AS HIGH AS 60 PCT OVER LAKE MICHIGAN AND 40 PCT INLAND NORTH OF HOLLAND TO US-131 JUST BEFORE MIDNIGHT. THE SPC 03Z SREF ALSO FORECASTS THUNDERSTORMS OVER LAKE MICHIGAN INTO SOUTHWEST LOWER MICHIGAN SIMILAR TO THE NAM THUNDERSTORM PROP CHART. ALL OF THIS TELLS ME WE SHOULD SEE THUNDERSTORMS DEVELOPING OVER LAKE MICHIGAN EARLY TONIGHT THEY WILL THEN MOVE INLAND DURING THE MID EVENING HOURS JUST AHEAD OF THE COLD FRONT. DUE TO THE SOUTHWEST WINDS THE BEST INSTABILITY (AIDED BY THE WARMTH OF LAKE MICHIGAN) WILL MOSTLY BE NORTH OF A LINE FROM HOLLAND TO ALMA. I ALSO INCREASED THE POP TONIGHT SINCE THERE IS LITTLE QUESTION GIVEN THE WARM LAKE AND DYNAMICS PLUS A DECENT SHOT AT DEEP MOISTURE THAT THERE WILL BE SHOWERS TONIGHT. ANY STORMS MAY HAVE SMALL HAIL GIVEN THE FREEZING LEVEL BEING BELOW 7000 FT. && .SHORT TERM...(TODAY THROUGH TUESDAY) ISSUED AT 344 AM EDT SUN OCT 20 2013 PCPN TRENDS AND TYPE ARE THE MAIN FOCUS OF THE FCST PACKAGE TODAY. THE SHOWER ACTIVITY THAT WAS WIDESPREAD ACROSS THE AREA LAST EVENING IS SCATTERING OUT AND DISSIPATING EARLY THIS MORNING. THIS IS DUE TO MAINLY THE UPPER FLOW TRANSITIONING TO ANTI-CYCLONIC AS THE LAST SHORT WAVE IN THIS SEQUENCE IS NOW LIFTING TO THE E/NE THIS MORNING. WE EXPECT THE SHOWER ACTIVITY TO PRETTY MUCH END FOR A FEW HOURS AS SHORT WAVE RIDGING BUILDS IN AND WE LOSE THE LOW LEVEL MOISTURE. SOME BREAKS IN THE CLOUDS WILL BE LIKELY ONCE AGAIN...HOWEVER JUST AS THE LOW LEVEL MOISTURE MOVES OUT...MID AND HIGH LEVEL MOISTURE FROM THE NEXT SYSTEM MOVES RIGHT IN. THE NEXT SYSTEM IN THE SEQUENCE WILL BE BRINGING PCPN TO THE FAR NW CORNER OF THE CWFA AS EARLY AS LATE THIS AFTERNOON. THIS WAVE IS CURRENTLY LOCATED NORTH OF LAKE WINNIPEG AND DROPPING SOUTHEAST QUICKLY. IT WILL MERGE WITH ANOTHER SHORT WAVE COMING INTO THE DAKOTAS. THE TRACK OF THE SHORT WAVE AND SFC LOW WILL FAVOR THE NRN SECTION OF THE CWFA FOR THE BEST PCPN CHCS. IT DOES LOOK LIKE THE ENTIRE CWFA WILL HAVE A CHC OF RAIN AS THE COLD FRONT PASSES THROUGH THE AREA VERY LATE TONIGHT AND MON MORNING. THE THREAT OF LAKE EFFECT RAIN SHOWERS WILL BE THERE ON MON WITH DELTA T/S EXPECTING TO BE AROUND 20C. THE THREAT DOES NOT LOOK TO BE VERY BIG HOWEVER AS THE DRY SLOT WILL AFFECT THE AREA BEHIND THE FRONT. MOISTURE PROFILES INDICATE THAT THEY WILL BE DEEP ENOUGH FOR SOME PCPN TO BE GENERATED AS THE DGZ WILL BARELY BE SATURATED. INVERSION HEIGHTS ARE SOMEWHAT LOW AS THE UPPER LOW AND CORE OF THE CYCLONIC FLOW STAYS MAINLY NORTH OF THE AREA. THE THREAT OF SHOWERS WILL CONTINUE TO BE POSSIBLE MON NIGHT AND EARLY TUE. THIS IS THE PERIOD WHEN IT LOOKS LIKE WE WILL SEE A POTENTIAL OF PCPN MIXING WITH OR CHANGING TO SNOW WITH H850 TEMPS DROPPING TO ALMOST -7C AND FREEZING LEVELS DROPPING BELOW 2000 FT. THE BEST POTENTIAL OF SEEING SOME SNOW WILL BE UP ACROSS CENTRAL LOWER MICHIGAN AT THE HIGHER ELEVATIONS. IN ADDITION TO THE POSSIBILITY OF SNOW...WE CAN NOT RULE OUT THUNDER ALONG THE LAKESHORE WITH LAKE MODIFIED PARCELS GENERATING OVER 1000 J/KG OF CAPE AND PARCELS REACHING TO -20C ISOTHERM. WATERSPOUTS WILL ALSO REMAIN POSSIBLE. .LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY) ISSUED AT 344 AM EDT SUN OCT 20 2013 THERE SEEMS TO BE NO END IN SIGHT TO THE COOL AND UNSETTLED PATTERN AS DEEP UPPER TROUGHING PERSISTS OVER THE GREAT LAKES REGION THROUGH ALL OF NEXT WEEK. TEMPERATURES WILL AVERAGE AROUND 10 DEGREES BELOW NORMAL. H8 TEMPS ARE PROGGED TO REMAIN RIGHT AROUND -6C THROUGH MOST OF THE WEEK CREATING EXTREME LAKE INSTABILITY WITH DELTA T/S IN EXCESS OF 20C. OCCASIONAL SHORTWAVES PIVOTING THROUGH THE REGION WILL PERIODICALLY BOOST INVERSION HEIGHTS AND BRING SLUGS OF DEEPER MOISTURE THROUGH WHICH WILL ENHANCE THE SHOWER ACTIVITY. THE FREEZING LEVEL WILL BE AROUND 1500 FT SO WOULD EXPECT TO SEE A MIXTURE OF RAIN/SNOW/GRAUPEL... ESPECIALLY INLAND FROM WARMING EFFECTS OF LK MI INCLUDING THE HWY 131 CORRIDOR. SOME ACCUMULATING WET SNOW LOOKS TO BE A REALISTIC THREAT FOR WEDNESDAY THROUGH THURSDAY NIGHT WHEN BOTH THE GFS AND ECMWF INDICATE THAT WE WILL BE ON THE CYCLONIC SHEAR SIDE OF THE UPPER JET CORE WHICH WILL BE POSITIONED TO OUR WEST AND SOUTH. WARM ADVECTION IS CURRENTLY PROGGED FOR NEXT SATURDAY AHEAD OF A SYSTEM DROPPING DOWN FROM THE NORTHWEST. THIS WOULD END THE LAKE EFFECT TEMPORARILY BUT THE CHANCE OF RAIN WILL CONTINUE DUE TO ISENTROPIC LIFT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 750 AM EDT SUN OCT 20 2013 HIGH CONFIDENCE EXISTS FOR WIDESPREAD VFR CONDITIONS TODAY. THE NEXT WEATHER MAKER ARRIVES AFTER 00Z TONIGHT WITH WIDESPREAD SHOWERS AND MVFR CONDITIONS DEVELOPING AT KMKG AND KGRR BY 03Z-06Z. THE SHOWERS SHOULD SPREAD INLAND OVER THE REST OF THE AREA AFTER 06Z TONIGHT... ALTHOUGH CONDITIONS SOUTH AND EAST OF GRR WILL LIKELY REMAIN VFR AS THE SHOWERS SHOULD NOT BE AS HEAVY AND PERSISTENT AS THEY WILL BE AT KMKG AND KGRR. WINDS WILL INCREASE OUT OF THE SOUTH TO 10 TO 20 KNOTS LATER THIS AFTERNOON AND BECOME SOUTHWEST OVERNIGHT. && .MARINE... ISSUED AT 1205 PM EDT SUN OCT 20 2013 I CONTINUED THE SMALL CRAFT ADVISORY INTO THIS EVENING AND THE GALE WARNING TONIGHT AND MONDAY. IT SEEMS TO ME THROUGH THAT THE WINDS WILL START TO DIMINISH MONDAY AFTERNOON. WE MAY BE ABLE TO DROP THE GALES BY MID AFTERNOON MONDAY. WATER SPOUTS WILL BE AN ISSUE ONCE THE WINDS DIMINISH BELOW GALES... SO I CONTINUED THE WATER SPOUTS IN THE NEAR SHORE FOR MONDAY NIGHT. && .HYDROLOGY... ISSUED AT 344 AM EDT SUN OCT 20 2013 WE ARE NOT ANTICIPATING ANY HYDROLOGY ISSUES IN THE NEXT WEEK. THE MAJORITY OF THE PCPN OVER THE NEXT WEEK WILL BE IN THE FORM OF SCATTERED SHOWERS. THIS TYPE OF PATTERN IS NOT CONDUCIVE FOR HEAVY RAINFALL WITH PRECIPITABLE WATERS RUNNING AROUND AVERAGE FOR THIS TIME OF YEAR. MOST LOCATIONS WILL NOT SEE PCPN OVER HALF AN INCH OVER THE NEXT FEW DAYS. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ844>849. GALE WARNING FROM 8 PM THIS EVENING TO 5 AM EDT TUESDAY FOR LMZ844>849. && $$ UPDATE...WDM SYNOPSIS...NJJ SHORT TERM...NJJ LONG TERM...MEADE AVIATION...MEADE HYDROLOGY...NJJ MARINE...WDM
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1036 AM EDT SUN OCT 20 2013 .SYNOPSIS... ISSUED AT 335 AM EDT SUN OCT 20 2013 COOL WEATHER WITH PERIODS OF LAKE EFFECT SHOWERS WILL CONTINUE INTO NEXT WEEK...AS A BROAD TROUGH OF LOW PRESSURE REMAINS OVER THE GREAT LAKES. EVEN COLDER AIR WILL ENGULF THE GREAT LAKES AND UPPER MIDWEST BY MONDAY...AS ANOTHER WEAK STORM SYSTEM EXITS NORTHEAST INTO QUEBEC EARLY IN THE WORK WEEK. TEMPERATURES MAY GET COLD ENOUGH TO BRING THE FIRST SNOWFALL OF THE SEASON...ESPECIALLY TO INTERIOR SECTIONS OF EASTERN UPPER AND NORTHERN LOWER MICHIGAN. && .UPDATE... ISSUED AT 1036 AM EDT SUN OCT 20 2013 GOT A BIT OF A BREAK DURING THE OVERNIGHT HOURS WITH CLOUDS THINNING/ CLEARING OUT OVER A GOOD PART OF CWA...WELL DOWNWIND OF THE LAKES. BUT MEANWHILE...LAKE AGGREGATE TROUGH ANALYZED FROM WESTERN LAKE SUPERIOR DOWN INTO NRN LAKE MICHIGAN THIS MORNING. MESOSCALE SFC LOW HAS DEVELOPED OVER NRN LAKE MICHIGAN GIVEN THE WEAKER SYNOPTIC WIND REGIME/SHORELINE ORIENTATION AND OFFSHORE WIND COMPONENT. A FEW POCKETS OF LAKE INDUCED SHOWERS LINGER WITHIN THIS FEATURE ACROSS NRN LAKE MICHIGAN (CAN SEE THE LOW LEVEL SPIN IN THE RADAR DATA...PUSHING UP INTO PARTS OF NW LOWER INTO THE STRAITS AND EASTERN UPPER. REST OF TODAY...POTENT SHORT WAVE AND POCKET OF COLDEST AIR OF THE SEASON ON TRACK TO DROP INTO THE UPPER MIDWEST...THAT WILL ULTIMATELY DRIVE A DEEPENING SFC LOW/POTENT COLD FRONT THROUGH THE REGION...LATE TONIGHT AND MONDAY MORNING. AHEAD OF THIS DEVELOPING SYSTEM...LOW LEVEL FLOW WILL BACK MORE SOUTHERLY AS WE GO THROUGH THE AFTERNOON...PUSHING REMAINING LAKE INDUCED SHOWERS UP THROUGH EASTERN UPPER MICHIGAN. PULSE OF LOW-MID LEVEL WARM ADVECTION FORCING AHEAD OF THAT DEVELOPING SYSTEM ALREADY PRODUCING A BAND OF PRECIP EXPANDING INTO WESTERN WISCONSIN THIS MORNING. FORCING LOOKING TO DEVELOP INTO THE W/SW PART OF THE CWA BY LATE AFTERNOON. GOING FORECAST ALREADY HAS CHANCY POPS OVER THE SW COUNTIES AND A SLIVER OF EASTERN UPPER MICHIGAN...WHICH LOOKS FINE FOR NOW. HAVE TWEAKED SKY FORECASTS FOR THE BALANCE OF THE DAY BASED ON TRENDS...TO HAVE A LITTLE MORE SUNSHINE THROUGH MIDDAY. ALSO TWEAKED TEMP CURVE FOR TONIGHT. BIG SURGE OF WARM AIR ALOFT AND INCREASING SOUTHERLY WINDS SHOULD ACTUALLY RESULT IN FLAT LINE OR EVEN WARMING TEMPS TONIGHT. JUST HOW WARM DEPENDS ON HOW FAR NORTH THE SFC WARM FRONT CAN GET...BUT CAN ENVISION SOME LOCATIONS PUSHING THE HIGH 40S TO NEAR 50 OVERNIGHT...BEFORE IT ALL CRASHES ON MONDAY WITH FROPA. UPDATE ISSUED AT 657 AM EDT SUN OCT 20 2013 CLOUDS HAVE OPENED UP CONSIDERABLY IN PARTS OF NE LOWER AND EASTERN UPPER MI. THIS WILL TEND TO SELF-DESTRUCT WITH HEATING TODAY...THE SUB-800MB AIRMASS REMAINS ON THE MOIST SIDE. SOME ADJUSTMENTS MADE TO EARLY-MORNING CLOUD COVER. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 335 AM EDT SUN OCT 20 2013 MUCH DISCUSSED DEEP TROUGHING CONTINUES TO DOMINATE GREAT LAKES WEATHER AT THIS EARLY HOUR...DOWNSTREAM OF EQUALLY IMPRESSIVE RIDGING POCKING UP AND BEYOND THE NORTHWEST TERRITORIES. SUBTLE WAVE TRAVERSING WITHIN THIS FLOW...NOW IN THE PROCESS OF FURTHER DEAMPLIFYING AND CUTTING ACROSS THE NORTHERN LAKES. THIS...COMBINED WITH STILL MORE THAN SUPPORTIVE OVER-WATER INSTABILITY (H8 TEMPERATURES RIGHT AROUND -2C PER HIGH RES RAP AND 00Z SOUNDING ANALYSIS)...CONTINUES TO KICK OFF LAKE ENHANCED RAIN SHOWERS OFF NORTHERN LAKE MICHIGAN (EVEN HAD SOME LEGITIMATE SNOWFLAKES MIX IN WITH THE RAIN HERE ON TOP OF THE HILL). OTHERWISE...A RATHER QUIET AND TOUCH CHILLY NIGHT...WITH CURRENT READINGS MAINLY IN THE 30S AND LOWER 40S. MAIN SYSTEM OF INTEREST THROUGH THE SHORT TERM IS WELL DEFINED SHORTWAVE/VORT LOBE DROPPING STRAIGHT SOUTH THROUGH CENTRAL MANITOBA. THIS SYSTEM WILL DRUM UP A RATHER RESPECTABLE AREA OF LOW PRESSURE TONIGHT AS IT DROPS INTO MINNESOTA. GOOD MID LEVEL SUPPORT AND LOW LEVEL ENERGY SUPPLIED BY WARM LAKE WATERS WILL HELP DEEPEN THIS SURFACE LOW AS IT MOVES UP INTO EASTERN LAKE SUPERIOR BY MONDAY MORNING. THIS SYSTEM WILL BRING MORE WIDESPREAD RAINS HEADING INTO TONIGHT...AND PERHAPS A GALE EVENT ON PARTS OF THE BIG WATERS. SHORT TERM FORECAST CONCERNS CENTER ON ADDRESSING THE IMPACTS OF THIS SYSTEM. BY AND LARGE...A RATHER NON-EVENTFUL WEATHER DAY EXPECTED TODAY. CURRENT OVERHEAD WAVE WILL HAVE EXITED STAGE RIGHT BY SUNRISE...LEAVING PURE LAKE PROCESSES FOR ANY ADDITIONAL SHOWER DEVELOPMENT THROUGH MID AFTERNOON. EXPECT THERE WILL BE SOME ONGOING TO START THE DAY...ESPECIALLY ALONG THE NORTHWEST LOWER COASTLINE WHERE WIND CONVERGENCE WILL BE MAXIMIZED. LAKE PROCESSES WILL BE A DOWNWARD ONE HEADING THROUGH THE DAY AS WINDS BACK SOUTHERLY AND WEAK MID LEVEL RIDGING BUILDS OVERHEAD. ATTENTION LATE THIS AFTERNOON INTO THE OVERNIGHT TURNS TO STRONG WAA RESPONSE AHEAD OF EARLIER MENTIONED DEEPENING SURFACE LOW. RATHER IMPRESSIVE ISENTROPIC UPGLIDE SIGNATURE VIA FORCED ASCENT ON NOSE OF 40+ KNOT LOW LEVEL JET...WITH WELL OVER HALF INCH PWATS ALSO SURGING NORTH INTO THE AREA WITH THIS JET. ABOVE LOOKS TO KICK OFF A RATHER LARGE AREA OF RAIN...WHICH WILL SPREAD RAPIDLY NORTHEAST ACROSS OUR AREA LATE THIS AFTERNOON INTO THIS EVENING. PER FULL 00Z GUIDANCE ANALYSIS...MAY AMP UP RAIN CHANCES SOME SOUTHWEST THIRD OF THE AREA AFTER 21Z TODAY...WITH INHERITED CATEGORICAL WORDING INTO THIS EVENING LOOKING GREAT. DRY SLOT PUNCHES IN FROM THE SOUTHWEST THROUGH THE OVERNIGHT...LIKELY ABRUPTLY ENDING RAINS AS IT DOES SO. MAY SEE SOME LAKE SHOWERS ATTEMPT TO FIRE FAR NORTHERN LAKE MICHIGAN TOWARDS MORNING WHERE MOISTURE WILL REMAIN DEEPER AND POST-COLD FRONT CAA REGIME ONCE AGAIN DROPS H8 READINGS TO JUST BELOW 0C. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 335 AM EDT SUN OCT 20 2013 CLASSIC LATE AUTUMN WX WILL REMAIN IN PLACE FOR THE UPCOMING WEEK...A BIT AHEAD OF SCHEDULE. PLENTY OF UPPER TROFFING WILL REMAIN IN PLACE IN CENTRAL CANADA AND ADJOINING PARTS OF THE STATES. THE LOWEST HEIGHTS WILL BE OVERHEAD MONDAY EVENING...AS AN UPPER LOW CROSSES EASTERN SUPERIOR. HOWEVER...HEIGHT RECOVERY AFTER THAT LOW EJECTS TO THE NE WILL BE ANEMIC. THAT WILL MAINTAIN MIXED PRECIP AS A SIGNIFICANT FORECAST CONCERN...ESPECIALLY DURING THE LATE NIGHT/ EARLY MORNING HOURS. PRECIP TRENDS ARE THE MAIN CONCERN. MONDAY...500MB LOW MOVES FROM INL TO MQT. 999MB SURFACE LOW OVER EASTERN SUPERIOR WILL LIFT NE TO SSW OF JAMES BAY...WITH A NEW LOW SPINNING UP ALONG A SECONDARY COLD FRONT IN CENTRAL SUPERIOR DURING THE AFTERNOON. THE BACK EDGE OF THE WARM CONVEYOR BELT WILL BE ABOUT TO EXIT NE LOWER MI AT 12Z...WITH DRIER MID LEVEL AIR IN THE PROCESS OF POURING INTO NORTHERN LOWER. HOWEVER...OVERLAKE INSTABILITY WILL BE INCREASING CONSIDERABLY AS COLDER LOW LEVEL AIR POURS IN. 850MB TEMPS OVER NORTHERN LAKE MI WILL NEAR -6C BY 18Z...-8C BY 00Z. MEANWHILE...EASTERN UPPER WILL REMAIN ON THE SOUTHERN PERIPHERY OF THE DEEPER WRAPAROUND MOISTURE. COULD STILL BE SOME FRONTAL SHRA IN FAR EASTERN SECTIONS TO START THE MORNING. SCT SHRA WILL GET GOING IN WSW-FLOW AREAS (ESPECIALLY FROM LEELANAU NORTHWARD) DURING THE MORNING...AS WELL AS IN EASTERN UPPER. THESE COULD BECOME MORE NUMEROUS IN THE AFTERNOON...AS INSTABILITY INCREASES (DELTA T/S IN THE LOWER 20S) AND THE CORE OF THE DRY SLOT MOVES EAST. 1000-850MB WINDS WILL VEER TO THE WEST DURING THE AFTERNOON...WITH INVERSION HEIGHTS A REASONABLY HEALTHY 6-7K FT. WILL INTRODUCE A SMALL CHANCE FOR A MIX VERY LATE IN THE DAY IN THE INTERIOR OF EASTERN UPPER...WHERE THE SURFACE-BASED MELTING LAYER IS NARROWING BELOW 1K FT. MAX TEMPS IN THE 40S (TO LOWER 50S NE LOWER) AND EARLY...WITH FALLING TEMPS IN THE PM. BRISK TO WINDY...ESPECIALLY NEAR LAKE MI. MON NIGHT/TUESDAY...UPPER LOW WILL GRADUALLY LIFT OUT TOWARD JAMES BAY...THOUGH WITH A SUBSTANTIAL SHORTWAVE ROUNDING IT/S SOUTHERN FLANK LATE MONDAY NIGHT. THAT WILL DRIVE THE SECONDARY FRONT INTO EASTERN UPPER MI LATE MONDAY NIGHT...AND ACROSS THE REST OF THE FORECAST AREA ON TUESDAY. 1000-850MB WINDS WILL BRIEFLY BACK MORE WSW AGAIN JUST AHEAD OF THIS TROF...ALLOWING THE INITIAL 850MB THERMAL TROF TO MOVE EAST AND BOOSTING 850MB TEMPS TO -5C. WINDS RAPIDLY VEER NW BEHIND THE TROF...AND COLD ADVECTION RESUMES. AFTER CONTINUED LOW-END-ISH LAKE EFFECT MONDAY EVENING (THOUGH WITH MORE SNOW MIXING IN AS DIURNAL HEATING IS LOST)...PRECIP WILL SUBSTANTIALLY RAMP UP OVERNIGHT AS THE SECONDARY FRONT AND SHARP 1000-850MB CONVERGENCE ARRIVES. SLUSHY ACCUMS UP TO AN INCH SEEM A DISTINCT POSSIBILITY MONDAY NIGHT NEAR GLR/BOYNE CITY/MANCELONA... AND IN WESTERN CHIP. TUESDAY WILL SEE A WOBBLY NW FLOW...BUT WITH MID-LEVEL DRYING/SUBSIDENCE AS THE VORT LOBE MOVES EAST. SOME LAKE EFFECT WILL CONTINUE...ESPECIALLY IN THE MORNING...WITH DISRUPTIVE DIURNAL HEATING DISORGANIZING THINGS IN THE PM. SOME SLOPPY LIGHT ACCUMS ARE AGAIN POSSIBLE IN THE MOST FAVORED AREAS OF BOTH PENINSULAS IN THE MORNING. MIN TEMPS WITHIN A FEW DEGREES OF 30F. MAX TEMPS NEAR 40F TO THE MID 40S. AND IT WILL REMAIN BRISK TO WINDY. REST OF THE FORECAST...FEW CHANGES NEEDED...AS COLD AND SHOWERY WX WILL PERSIST AS CURRENTLY FORECAST. NEW ECMWF IS FLAT-OUT COLD STRAIGHT THRU 240HRS. (PROBABLY BEST FOR MOTHER NATURE TO GET THIS OUT OF HER SYSTEM NOW.) && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 657 AM EDT SUN OCT 20 2013 SCT/NMRS LAKE ENHANCED RAIN SHOWERS WILL CONTINUE TO IMPACT NRN LWR MICHIGAN TAF SITES THRU SUNDAY NIGHT THANKS TO DEEP CYCLONIC FLOW...COLD AIR ACTIVATING THE LAKES AND AMPLE LOW LEVEL MOISTURE. OVERALL...CIGS WILL REMAIN LOW VFR...BUT MAY BRIEFLY DROP TO HIGH MVFR WITHIN SOME OF THE HEAVIER SHOWER ACTIVITY...ESPECIALLY TONIGHT. WESTERLY WINDS UNDER 10 KTS TONIGHT WILL SHIFT TO THE S/SW ON SUNDAY AHEAD OF DEEPENING LOW PRESSURE SLIDING INTO THE UPPER MISSISSIPPI VALLEY. LLWS TONIGHT AT ALL TAF SITES FOR PART OF TONIGHT. && .MARINE... ISSUED AT 335 AM EDT SUN OCT 20 2013 RELATIVELY LIGHT WINDS THIS MORNING GIVES WAY TO INCREASINGLY GUSTY SOUTH FLOW LATER THIS AFTERNOON...AND ESPECIALLY TONIGHT...AS LOW PRESSURE INTENSIFIES AND PUSHES INTO EASTERN LAKE SUPERIOR BY MONDAY MORNING. TIGHTENING PRESSURE GRADIENT AND ONSET OF IMPRESSIVE SURGE OF CAA WILL LEAD TO VERY GUSTY WEST TO SOUTHWEST WINDS DURING THE DAY MONDAY...WITH THE STRONGEST WINDS EXPECTED OVER NORTHERN LAKE MICHIGAN. GALE FORCE WIND GUSTS APPEAR INCREASINGLY LIKELY...RESULTING IN AN UPGRADE TO INHERITED NORTHERN LAKE MICHIGAN GALE WATCH TO A WARNING. IN ADDITION...WIND GUST MAY REACH GALE FORCE ACROSS WHITEFISH BAY AND THE ST. MARYS RIVER LATER MONDAY MORNING THROUGH THE AFTERNOON. CONFIDENCE NOT HIGH ENOUGH TO WARRANT A GALE WARNING...BUT ENOUGH CONCERN TO HOIST A GALE WATCH FOR THESE AREAS. ADDITIONAL SCA/S WILL LIKELY BE NEEDED FOR OTHER NEARSHORE ZONES...BUT WILL FOCUS ON GALE CONDITIONS AND PUNT ADVISORY ISSUANCES TO FUTURE FORECAST SHIFTS. WELCOME TO FALL ON THE GREAT LAKES! && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LHZ345. LM...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LMZ341- 342-344>346. LS...GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ321- 322. && $$ UPDATE...BA SYNOPSIS...JZ SHORT TERM...MB LONG TERM...JZ AVIATION...JZ MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
734 AM EDT SUN OCT 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT SUN OCT 20 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND ERN CONUS. ONE UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER THE DAKOTAS WHILE ANOTHER STRONGER PV ANOMALY WAS DROPPING TO THE SSE THROUGH CNTRL MANITOBA. 290K ISENTROPIC LIFT AHEAD OF A SFC LOW OVER THE CNTRL DAKOTAS SUPPORTED AREAS OF RAIN OVER THE ERN DAKOTAS INTO WRN MN. 850 MB TEMPS AROUND -4C HELPED TO MAINTAIN A LAKE INDUCED TROUGH OVER LAKE SUPERIOR IN THE LIGHT WIND REGIME. ISOLD LAKE EFFECT -SHRA LINGERED INTO NW UPPER MI AND ERN LAKE SUPERIOR. THE MODELS WERE IN RELATIVELY GOOD AGREEMENT WITH THE SHORTWAVES AND SFC LOW MOVING INTO THE WRN GREAT LAKES. AS THE SFC LOW TRACKS FROM WRN MN SUNDAY MORNING TO THE SE END OF LAKE SUPERIOR EARLY MON MORNING...DEEP LAYER QVECTOR CONV AND 285K-295K ISENTROPIC LIFT WILL SUPPORT AN AREA OF PCPN MOVING INTO SW UPPER MI SUN AFTERNOON AND ACROSS THE CWA SUN NIGHT. PCPN AMOUNTS IN THE 0.25 TO 0.50 INCH RANGE ARE EXPECTED. MODEL FCST SOUNDINGS...AND WET-BULB ZERO HEIGHTS SUPPORT THE POTENTIAL FOR A SOME SNOW ACCUMULATION OVER THE HIGHER TERRAIN OF THE WEST HALF OF UPPER MI. WITH ONLY LIGHT TO MODERATE SNOWFALL RATES EXPECTED...AND RELATIVELY LOW SNOW/WATER RATIO VALUES BELOW 10/1...ANY SNOW ACCUMULATION SHOULD GENERALLY REMAIN AT OR BELOW 2 INCHES. THERE MAY ALSO BE SOME ADDITIONAL LAKE ENHANCED SNOW INTO NW UPPER MI LATE AS WNW WINDS STRENGTHEN BEHIND THE LOW. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 337 AM EDT SUN OCT 20 2013 AN ACTIVE WEATHER PATTERN IS IN STORE FOR THE UPPER GREAT LAKES REGION FOR THE UPCOMING WORK WEEK. THE UPPER TROUGH THAT IS AFFECTING THE UPPER GREAT LAKES WILL BE RE-ENFORCED BY A SHORTWAVE CURRENTLY DROPPING SOUTH OVER LAKE WINNIPEG. THIS WAVE WILL CATCH UP WITH THE SURFACE LOW AND SHORTWAVE IN SOUTHERN MINNESOTA (CURRENTLY IN WESTERN NORTH DAKOTA) AND INTENSIFY THE LOW TONIGHT AS THE SHORTWAVES PHASE...CAUSING THE LOW TO LIFT NORTHEAST AND OVER EASTERN LAKE SUPERIOR BY 12Z MONDAY. MODELS SEEM TO BE COMING INTO BETTER AGREEMENT ON THE TRACK/INTENSITY OF THE LOW AS IT MOVES NORTH FROM EASTERN LAKE SUPERIOR ON MONDAY...WHILE LEAVING A SURFACE TROUGH BACK OVER THE LAKE THROUGH MONDAY NIGHT. EXPECT THE INITIAL SURGE OF PRECIPITATION THAT MOVES THROUGH SUNDAY AFTERNOON/NIGHT TO BE PUSHING NORTHEAST OF UPPER MICHIGAN. THUS...WITH COLD AIR SURGING EAST ACROSS UPPER MICHIGAN UNDER THE GUSTY WESTERLY FLOW...EXPECT THE MAIN WEATHER TO START MONDAY TO BE WESTERLY WIND LAKE ENHANCED PRECIPITATION. THIS IS DUE TO 850MB TEMPS FALLING TO -8C OVER WESTERN UPPER MICHIGAN BY 18Z MONDAY. WILL HIGHLIGHT THE HIGHEST POPS OVER THE HIGHER TERRAIN FROM THE KEWEENAW THROUGH THE GOGEBIC RANGE AND ALSO OVER THE HURON MOUNTAINS. WESTERLY WINDS LOOK TO BACK SLIGHTLY IN THE AFTERNOON AHEAD OF TROUGH DROPPING SOUTH ACROSS WESTERN LAKE SUPERIOR DURING THE LATE AFTERNOON. THIS MAY CAUSE THE BEST PRECIPITATION TO BE FOCUSED MORE OVER THE KEWEENAW DURING THE AFTERNOON. THEREFORE...DID OPT TO TRIM POP/QPF AMOUNTS OVER GOGEBIC/ONTONAGON COUNTIES SOME DURING THE AFTERNOON HOURS. SINCE WETBULB ZERO VALUES FALL OVER THE WEST AS THE COLD AIR SURGES EAST ACROSS THE U.P. EXPECT PRECIP TO FALL AS SNOW OVER THE WEST...BUT COULD MIX WITH RAIN AT TIMES NEAR LAKE SUPERIOR. SNOWFALL AMOUNTS DURING THE MORNING AND MOST OF THE AFTERNOON SHOULD BE LIGHT...WITH LOCATIONS SEEING AMOUNTS UNDER AN INCH. OVER THE REST OF UPPER MICHIGAN DURING THIS PERIOD...EXPECT BREEZY WESTERLY WINDS AND CLOUDY CONDITIONS...BUT LITTLE TO NO PRECIPITATION IS EXPECTED. THE BEST OPPORTUNITY WOULD BE OVER THE EAST RIGHT ALONG THE LAKE SUPERIOR/MICHIGAN SHORELINES AS LAKE ENHANCED PRECIPITATION WILL TRY TO PARALLEL THOSE AREAS. THEN TOWARDS SUNSET...THE SURFACE TROUGH WILL DROP SOUTH ONTO THE WESTERN U.P. SHORELINE AND BRING AN ENHANCED AREA OF CONVERGENCE AND PRECIPITATION. EXPECT THERE TO BE MODERATE TO HEAVY PRECIPITATION AS THIS TROUGH SLIDES THROUGH THE WESTERN U.P. DURING THE EVENING HOURS AND THEN THROUGH CENTRAL UPPER MICHIGAN DURING THE OVERNIGHT HOURS. 850MB TEMPS WILL ACTUALLY WARM A COUPLE DEGREES BEHIND THE TROUGH...BUT THE DEEP MOISTURE AND CYCLONIC FLOW ON THE BACK SIDE OF THE SURFACE AND 850MB LOW...ALONG WITH UPSLOPE WINDS...WILL SUPPORT LAKE ENHANCED PRECIPITATION THROUGH A GOOD PORTION OF THE NIGHT OVER THE WESTERN CWA AND INTO TUESDAY MORNING OVER THE NORTH CENTRAL CWA. THE PRECIPITATION DURING THIS PERIOD SHOULD FALL AS SNOW EXCEPT FOR LOCATIONS RIGHT ALONG THE LAKE SUPERIOR SHORELINE WHERE THE NORTH-NORTHWEST WINDS WOULD PRODUCE SOME HEAT TRANSFER FROM THE LAKE AND LEAD TO SOME RAIN/SNOW MIX. AS FOR RATIOS/AMOUNTS...THINKING THE SNOW RATIOS WILL BE AROUND OR JUST BELOW 10-1 WITH THE BEST FORCING BEING BELOW THE DGZ AND SNOW FLAKES FALLING FROM ALOFT CLUMPING TOGETHER AS THEY REACH THE STRONG UPWARD MOTION NEAR THE SURFACE. AS FOR QPF AMOUNTS...HPC INDICATES NAM IS THE COLDER SOLUTION IN THE MID LEVELS (BY AROUND 2C) BEHIND THE LOW...WHICH MAY BE PART OF THE REASON IT IS MUCH HIGHER ON QPF AMOUNTS WITH THE LAKE ENHANCED SNOW BEHIND THE TROUGH. SINCE THE HIGHER RESOLUTION OF THE NAM AND 4KM NEST PICK UP THE TERRAIN ENHANCEMENT...DID BLEND THAT WITH THE PREFERRED WARMER AND COARSER MODELS FOR QPF MONDAY AFTERNOON THROUGH TUESDAY MORNING. THIS CREATES 24HR VALUES OF 0.5-0.75IN FROM IRONWOOD THROUGH THE KEWEENAW AND ALSO OVER THE WESTERN SIDE OF THE HURON MOUNTAINS. AT 10-1 SLR VALUE...SNOWFALL AMOUNTS IN THE 3-6 INCH RANGE SEEM REASONABLE IN THOSE AREAS AFTER FACTORING SOME MELTING INITIALLY ON MONDAY WHEN THE SNOWFALL RATES ARE LIGHTER. THAT SEEMS TO FIT IN WITH OUR ADVISORY CRITERIA AND WILL LIKELY END UP JUST UNDER THE 6INCH IN 12HR MARK FOR WARNINGS. CIPS TOP ANALOGS (BASED OFF THE SLIGHTLY COLDER NAM SOLUTION) SHOW MEAN SNOWFALL AMOUNTS OF 4-8 INCHES OF A 72HR PERIOD AND PROBABILITIES OF SEEING 6IN OF SNOW AROUND 60 PERCENT. THINK THE FORECAST MATCHES UP PRETTY WELL WITH THAT IDEA (ALONG WITH HPC GUIDANCE) AND WILL CONTINUE TO HIGHLIGHT THIS MEASUREABLE SNOW EVENT IN THE HWO AND ISSUE AN SPS TO HIGHTEN THE AWARENESS. SURFACE TROUGH WILL QUICKLY SHIFT EAST OF THE AREA ON TUESDAY...AS AN AREA OF HIGH PRESSURE SLIDES INTO THE NORTHERN PLAINS. EXPECT A DIMINISHING PRECIPITATION TREND FROM WEST TO EAST ACROSS THE CWA WITH THE DEEPER MOISTURE DEPARTING. THROUGH THE REST OF THE WEEK...EXPECT NORTHWESTERLY FLOW TO BE IN PLACE AS THE LOW SITS OVER QUEBEC AND A SERIES OF HIGHS DROP SOUTHEAST THROUGH THE NORTHERN PLAINS. 850MB TEMPS THROUGH THE REST OF THE PERIOD SHOULD BE RIGHT AROUND -8C WHICH LEADS TO PLENTY OF LAKE INSTABILITY. WILL CONTINUE TO HIGHLIGHT CHANCE POPS OR HIGHER IN THE TRADITIONAL NORTHWEST FLOW LOCATIONS THROUGH FRIDAY. HIGHEST POPS AND POTENTIAL FOR ACCUMULATION SNOWFALL WILL BE OVER THE EASTERN U.P. WITH THE LONGER FETCH AND CLOSER PROXIMITY TO THE BETTER MOISTURE UNDER THE UPPER LOW. THERE WILL BE A COUPLE BRIEF PERIODS WHERE THE LAKE EFFECT PRECIPITATION WILL PICKUP AS WEAK SHORTWAVES AND BETTER MOISTURE SWEEP THROUGH. CIPS TOP ANALOGS FOR THE MID WEEK PERIOD UNDER PERSISTENT LAKE EFFECT SNOWFALL SHOWS PROBABILITY FOR 4IN OF SNOW IN A 72HR PERIOD BEING AROUND 60 PERCENT IN THE TRADITIONAL FAVORED NORTHWEST FLOW LOCATIONS. BEING THAT IS OVER A 3 DAY PERIOD...THING THOSE VALUES ARE REASONABLE WITH LIGHT ACCUMULATIONS OCCURRING THROUGH THE END OF THE WORK WEEK. THE UPPER TROUGHS INFLUENCE ON THE UPPER GREAT LAKES LOOKS TO WEAKEN THIS WEEKEND AS IT SHIFTS EAST INTO THE NEW ENGLAND STATES. BUT ANOTHER SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE ROCKIES WILL TRY TO MOVE INTO THE AREA FOR THE SECOND HALF OF THE WEEKEND. WILL JUST GO WITH A GENERAL CONSENSUS AND HAVE CHANCE POPS WITH TEMPERATURES REMAINING BELOW NORMAL. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 733 AM EDT SUN OCT 20 2013 ARRIVAL OF A WEAK HIGH PRESSURE RIDGE SHOULD BRING VFR CONDITIONS TO ALL THE SITES FOR MUCH OF THE DAY TODAY...BUT THICKER CLOUDS AND RAIN WILL ARRIVE SW TO NE SUN AFTERNOON AND EVENING AHEAD OF LOW PRES MOVING THROUGH THE UPPER LAKES. EXPECT CONDITIONS TO DETERIORATE TO MVFR AT ALL 3 SITES AND EVEN IFR AT IWD UNDER STEADY RA WITH UPSLOPE NE WIND. SAW AND CMX ARE ALSO EXPECTED TO DROP TO IFR WITH THE PERSISTENT LIGHT RAIN. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT SUN OCT 20 2013 LOW PRESSURE MOVEING OUT OF THE DAKOTAS WILL BEGIN TO INTENSIFY OVER THE UPPER MISSISSIPPI VALLEY TODAY AND THEN MOVE THROUGH THE UPPER GREAT LAKES TONIGHT AND MONDAY. AS THIS OCCURS...WINDS WILL STRENGTHEN ACROSS THE LAKE...FIRST OUT OF THE SOUTH TO SOUTHEAST AHEAD OF THE LOW THIS EVENING AND THEN OUT OF THE WEST BEHIND THE LOW LATE TONIGHT INTO MONDAY. THERE STILL ARE SOME DIFFERENCES IN THE EXACT TRACK AND STRENGTH OF THE LOW AS IT MOVES ACROSS LAKE SUPERIOR ON MONDAY...SO WIND SPEED/DIRECTIONS ARE STILL UNCERTAIN. AT THIS TIME...IT APPEARS THE STRONGEST WINDS WILL BE BEHIND THE LOW ON MONDAY AND MONDAY NIGHT...WHEN WEST GALES TO 35-40KTS VEERING TO THE NORTH ARE EXPECTED. ONCE THE LOW DEPARTS THE AREA...EXPECT NORTHWESTERLY WINDS UP TO 25KTS TO REMAIN OVER LAKE SUPERIOR INTO WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY AFTERNOON FOR LSZ265>267. GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR LSZ264. GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
700 AM EDT SUN OCT 20 2013 .SYNOPSIS... ISSUED AT 335 AM EDT SUN OCT 20 2013 COOL WEATHER WITH PERIODS OF LAKE EFFECT SHOWERS WILL CONTINUE INTO NEXT WEEK...AS A BROAD TROUGH OF LOW PRESSURE REMAINS OVER THE GREAT LAKES. EVEN COLDER AIR WILL ENGULF THE GREAT LAKES AND UPPER MIDWEST BY MONDAY...AS ANOTHER WEAK STORM SYSTEM EXITS NORTHEAST INTO QUEBEC EARLY IN THE WORK WEEK. TEMPERATURES MAY GET COLD ENOUGH TO BRING THE FIRST SNOWFALL OF THE SEASON...ESPECIALLY TO INTERIOR SECTIONS OF EASTERN UPPER AND NORTHERN LOWER MICHIGAN. && .UPDATE... ISSUED AT 657 AM EDT SUN OCT 20 2013 CLOUDS HAVE OPENED UP CONSIDERABLY IN PARTS OF NE LOWER AND EASTERN UPPER MI. THIS WILL TEND TO SELF-DESTRUCT WITH HEATING TODAY...THE SUB-800MB AIRMASS REMAINS ON THE MOIST SIDE. SOME ADJUSTMENTS MADE TO EARLY-MORNING CLOUD COVER. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 335 AM EDT SUN OCT 20 2013 MUCH DISCUSSED DEEP TROUGHING CONTINUES TO DOMINATE GREAT LAKES WEATHER AT THIS EARLY HOUR...DOWNSTREAM OF EQUALLY IMPRESSIVE RIDGING POCKING UP AND BEYOND THE NORTHWEST TERRITORIES. SUBTLE WAVE TRAVERSING WITHIN THIS FLOW...NOW IN THE PROCESS OF FURTHER DEAMPLIFYING AND CUTTING ACROSS THE NORTHERN LAKES. THIS...COMBINED WITH STILL MORE THAN SUPPORTIVE OVER-WATER INSTABILITY (H8 TEMPERATURES RIGHT AROUND -2C PER HIGH RES RAP AND 00Z SOUNDING ANALYSIS)...CONTINUES TO KICK OFF LAKE ENHANCED RAIN SHOWERS OFF NORTHERN LAKE MICHIGAN (EVEN HAD SOME LEGITIMATE SNOWFLAKES MIX IN WITH THE RAIN HERE ON TOP OF THE HILL). OTHERWISE...A RATHER QUIET AND TOUCH CHILLY NIGHT...WITH CURRENT READINGS MAINLY IN THE 30S AND LOWER 40S. MAIN SYSTEM OF INTEREST THROUGH THE SHORT TERM IS WELL DEFINED SHORTWAVE/VORT LOBE DROPPING STRAIGHT SOUTH THROUGH CENTRAL MANITOBA. THIS SYSTEM WILL DRUM UP A RATHER RESPECTABLE AREA OF LOW PRESSURE TONIGHT AS IT DROPS INTO MINNESOTA. GOOD MID LEVEL SUPPORT AND LOW LEVEL ENERGY SUPPLIED BY WARM LAKE WATERS WILL HELP DEEPEN THIS SURFACE LOW AS IT MOVES UP INTO EASTERN LAKE SUPERIOR BY MONDAY MORNING. THIS SYSTEM WILL BRING MORE WIDESPREAD RAINS HEADING INTO TONIGHT...AND PERHAPS A GALE EVENT ON PARTS OF THE BIG WATERS. SHORT TERM FORECAST CONCERNS CENTER ON ADDRESSING THE IMPACTS OF THIS SYSTEM. BY AND LARGE...A RATHER NON-EVENTFUL WEATHER DAY EXPECTED TODAY. CURRENT OVERHEAD WAVE WILL HAVE EXITED STAGE RIGHT BY SUNRISE...LEAVING PURE LAKE PROCESSES FOR ANY ADDITIONAL SHOWER DEVELOPMENT THROUGH MID AFTERNOON. EXPECT THERE WILL BE SOME ONGOING TO START THE DAY...ESPECIALLY ALONG THE NORTHWEST LOWER COASTLINE WHERE WIND CONVERGENCE WILL BE MAXIMIZED. LAKE PROCESSES WILL BE A DOWNWARD ONE HEADING THROUGH THE DAY AS WINDS BACK SOUTHERLY AND WEAK MID LEVEL RIDGING BUILDS OVERHEAD. ATTENTION LATE THIS AFTERNOON INTO THE OVERNIGHT TURNS TO STRONG WAA RESPONSE AHEAD OF EARLIER MENTIONED DEEPENING SURFACE LOW. RATHER IMPRESSIVE ISENTROPIC UPGLIDE SIGNATURE VIA FORCED ASCENT ON NOSE OF 40+ KNOT LOW LEVEL JET...WITH WELL OVER HALF INCH PWATS ALSO SURGING NORTH INTO THE AREA WITH THIS JET. ABOVE LOOKS TO KICK OFF A RATHER LARGE AREA OF RAIN...WHICH WILL SPREAD RAPIDLY NORTHEAST ACROSS OUR AREA LATE THIS AFTERNOON INTO THIS EVENING. PER FULL 00Z GUIDANCE ANALYSIS...MAY AMP UP RAIN CHANCES SOME SOUTHWEST THIRD OF THE AREA AFTER 21Z TODAY...WITH INHERITED CATEGORICAL WORDING INTO THIS EVENING LOOKING GREAT. DRY SLOT PUNCHES IN FROM THE SOUTHWEST THROUGH THE OVERNIGHT...LIKELY ABRUPTLY ENDING RAINS AS IT DOES SO. MAY SEE SOME LAKE SHOWERS ATTEMPT TO FIRE FAR NORTHERN LAKE MICHIGAN TOWARDS MORNING WHERE MOISTURE WILL REMAIN DEEPER AND POST-COLD FRONT CAA REGIME ONCE AGAIN DROPS H8 READINGS TO JUST BELOW 0C. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 335 AM EDT SUN OCT 20 2013 CLASSIC LATE AUTUMN WX WILL REMAIN IN PLACE FOR THE UPCOMING WEEK...A BIT AHEAD OF SCHEDULE. PLENTY OF UPPER TROFFING WILL REMAIN IN PLACE IN CENTRAL CANADA AND ADJOINING PARTS OF THE STATES. THE LOWEST HEIGHTS WILL BE OVERHEAD MONDAY EVENING...AS AN UPPER LOW CROSSES EASTERN SUPERIOR. HOWEVER...HEIGHT RECOVERY AFTER THAT LOW EJECTS TO THE NE WILL BE ANEMIC. THAT WILL MAINTAIN MIXED PRECIP AS A SIGNIFICANT FORECAST CONCERN...ESPECIALLY DURING THE LATE NIGHT/ EARLY MORNING HOURS. PRECIP TRENDS ARE THE MAIN CONCERN. MONDAY...500MB LOW MOVES FROM INL TO MQT. 999MB SURFACE LOW OVER EASTERN SUPERIOR WILL LIFT NE TO SSW OF JAMES BAY...WITH A NEW LOW SPINNING UP ALONG A SECONDARY COLD FRONT IN CENTRAL SUPERIOR DURING THE AFTERNOON. THE BACK EDGE OF THE WARM CONVEYOR BELT WILL BE ABOUT TO EXIT NE LOWER MI AT 12Z...WITH DRIER MID LEVEL AIR IN THE PROCESS OF POURING INTO NORTHERN LOWER. HOWEVER...OVERLAKE INSTABILITY WILL BE INCREASING CONSIDERABLY AS COLDER LOW LEVEL AIR POURS IN. 850MB TEMPS OVER NORTHERN LAKE MI WILL NEAR -6C BY 18Z...-8C BY 00Z. MEANWHILE...EASTERN UPPER WILL REMAIN ON THE SOUTHERN PERIPHERY OF THE DEEPER WRAPAROUND MOISTURE. COULD STILL BE SOME FRONTAL SHRA IN FAR EASTERN SECTIONS TO START THE MORNING. SCT SHRA WILL GET GOING IN WSW-FLOW AREAS (ESPECIALLY FROM LEELANAU NORTHWARD) DURING THE MORNING...AS WELL AS IN EASTERN UPPER. THESE COULD BECOME MORE NUMEROUS IN THE AFTERNOON...AS INSTABILITY INCREASES (DELTA T/S IN THE LOWER 20S) AND THE CORE OF THE DRY SLOT MOVES EAST. 1000-850MB WINDS WILL VEER TO THE WEST DURING THE AFTERNOON...WITH INVERSION HEIGHTS A REASONABLY HEALTHY 6-7K FT. WILL INTRODUCE A SMALL CHANCE FOR A MIX VERY LATE IN THE DAY IN THE INTERIOR OF EASTERN UPPER...WHERE THE SURFACE-BASED MELTING LAYER IS NARROWING BELOW 1K FT. MAX TEMPS IN THE 40S (TO LOWER 50S NE LOWER) AND EARLY...WITH FALLING TEMPS IN THE PM. BRISK TO WINDY...ESPECIALLY NEAR LAKE MI. MON NIGHT/TUESDAY...UPPER LOW WILL GRADUALLY LIFT OUT TOWARD JAMES BAY...THOUGH WITH A SUBSTANTIAL SHORTWAVE ROUNDING IT/S SOUTHERN FLANK LATE MONDAY NIGHT. THAT WILL DRIVE THE SECONDARY FRONT INTO EASTERN UPPER MI LATE MONDAY NIGHT...AND ACROSS THE REST OF THE FORECAST AREA ON TUESDAY. 1000-850MB WINDS WILL BRIEFLY BACK MORE WSW AGAIN JUST AHEAD OF THIS TROF...ALLOWING THE INITIAL 850MB THERMAL TROF TO MOVE EAST AND BOOSTING 850MB TEMPS TO -5C. WINDS RAPIDLY VEER NW BEHIND THE TROF...AND COLD ADVECTION RESUMES. AFTER CONTINUED LOW-END-ISH LAKE EFFECT MONDAY EVENING (THOUGH WITH MORE SNOW MIXING IN AS DIURNAL HEATING IS LOST)...PRECIP WILL SUBSTANTIALLY RAMP UP OVERNIGHT AS THE SECONDARY FRONT AND SHARP 1000-850MB CONVERGENCE ARRIVES. SLUSHY ACCUMS UP TO AN INCH SEEM A DISTINCT POSSIBILITY MONDAY NIGHT NEAR GLR/BOYNE CITY/MANCELONA... AND IN WESTERN CHIP. TUESDAY WILL SEE A WOBBLY NW FLOW...BUT WITH MID-LEVEL DRYING/SUBSIDENCE AS THE VORT LOBE MOVES EAST. SOME LAKE EFFECT WILL CONTINUE...ESPECIALLY IN THE MORNING...WITH DISRUPTIVE DIURNAL HEATING DISORGANIZING THINGS IN THE PM. SOME SLOPPY LIGHT ACCUMS ARE AGAIN POSSIBLE IN THE MOST FAVORED AREAS OF BOTH PENINSULAS IN THE MORNING. MIN TEMPS WITHIN A FEW DEGREES OF 30F. MAX TEMPS NEAR 40F TO THE MID 40S. AND IT WILL REMAIN BRISK TO WINDY. REST OF THE FORECAST...FEW CHANGES NEEDED...AS COLD AND SHOWERY WX WILL PERSIST AS CURRENTLY FORECAST. NEW ECMWF IS FLAT-OUT COLD STRAIGHT THRU 240HRS. (PROBABLY BEST FOR MOTHER NATURE TO GET THIS OUT OF HER SYSTEM NOW.) && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 657 AM EDT SUN OCT 20 2013 SCT/NMRS LAKE ENHANCED RAIN SHOWERS WILL CONTINUE TO IMPACT NRN LWR MICHIGAN TAF SITES THRU SUNDAY NIGHT THANKS TO DEEP CYCLONIC FLOW...COLD AIR ACTIVATING THE LAKES AND AMPLE LOW LEVEL MOISTURE. OVERALL...CIGS WILL REMAIN LOW VFR...BUT MAY BRIEFLY DROP TO HIGH MVFR WITHIN SOME OF THE HEAVIER SHOWER ACTIVITY...ESPECIALLY TONIGHT. WESTERLY WINDS UNDER 10 KTS TONIGHT WILL SHIFT TO THE S/SW ON SUNDAY AHEAD OF DEEPENING LOW PRESSURE SLIDING INTO THE UPPER MISSISSIPPI VALLEY. LLWS TONIGHT AT ALL TAF SITES FOR PART OF TONIGHT. && .MARINE... ISSUED AT 335 AM EDT SUN OCT 20 2013 RELATIVELY LIGHT WINDS THIS MORNING GIVES WAY TO INCREASINGLY GUSTY SOUTH FLOW LATER THIS AFTERNOON...AND ESPECIALLY TONIGHT...AS LOW PRESSURE INTENSIFIES AND PUSHES INTO EASTERN LAKE SUPERIOR BY MONDAY MORNING. TIGHTENING PRESSURE GRADIENT AND ONSET OF IMPRESSIVE SURGE OF CAA WILL LEAD TO VERY GUSTY WEST TO SOUTHWEST WINDS DURING THE DAY MONDAY...WITH THE STRONGEST WINDS EXPECTED OVER NORTHERN LAKE MICHIGAN. GALE FORCE WIND GUSTS APPEAR INCREASINGLY LIKELY...RESULTING IN AN UPGRADE TO INHERITED NORTHERN LAKE MICHIGAN GALE WATCH TO A WARNING. IN ADDITION...WIND GUST MAY REACH GALE FORCE ACROSS WHITEFISH BAY AND THE ST. MARYS RIVER LATER MONDAY MORNING THROUGH THE AFTERNOON. CONFIDENCE NOT HIGH ENOUGH TO WARRANT A GALE WARNING...BUT ENOUGH CONCERN TO HOIST A GALE WATCH FOR THESE AREAS. ADDITIONAL SCA/S WILL LIKELY BE NEEDED FOR OTHER NEARSHORE ZONES...BUT WILL FOCUS ON GALE CONDITIONS AND PUNT ADVISORY ISSUANCES TO FUTURE FORECAST SHIFTS. WELCOME TO FALL ON THE GREAT LAKES! && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LHZ345. LM...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LMZ341- 342-344>346. LS...GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ321- 322. && $$ UPDATE...JZ SYNOPSIS...JZ SHORT TERM...MB LONG TERM...JZ AVIATION...JZ MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
512 AM EDT SUN OCT 20 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 510 AM EDT SUN OCT 20 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND A BROAD MID/UPPER LEVEL TROUGH ACROSS THE CNTRL AND ERN CONUS. ONE UPSTREAM SHORTWAVE TROUGH WAS LOCATED OVER THE DAKOTAS WHILE ANOTHER STRONGER PV ANOMALY WAS DROPPING TO THE SSE THROUGH CNTRL MANITOBA. 290K ISENTROPIC LIFT AHEAD OF A SFC LOW OVER THE CNTRL DAKOTAS SUPPORTED AREAS OF RAIN OVER THE ERN DAKOTAS INTO WRN MN. 850 MB TEMPS AROUND -4C HELPED TO MAINTAIN A LAKE INDUCED TROUGH OVER LAKE SUPERIOR IN THE LIGHT WIND REGIME. ISOLD LAKE EFFECT -SHRA LINGERED INTO NW UPPER MI AND ERN LAKE SUPERIOR. THE MODELS WERE IN RELATIVELY GOOD AGREEMENT WITH THE SHORTWAVES AND SFC LOW MOVING INTO THE WRN GREAT LAKES. AS THE SFC LOW TRACKS FROM WRN MN SUNDAY MORNING TO THE SE END OF LAKE SUPERIOR EARLY MON MORNING...DEEP LAYER QVECTOR CONV AND 285K-295K ISENTROPIC LIFT WILL SUPPORT AN AREA OF PCPN MOVING INTO SW UPPER MI SUN AFTERNOON AND ACROSS THE CWA SUN NIGHT. PCPN AMOUNTS IN THE 0.25 TO 0.50 INCH RANGE ARE EXPECTED. MODEL FCST SOUNDINGS...AND WET-BULB ZERO HEIGHTS SUPPORT THE POTENTIAL FOR A SOME SNOW ACCUMULATION OVER THE HIGHER TERRAIN OF THE WEST HALF OF UPPER MI. WITH ONLY LIGHT TO MODERATE SNOWFALL RATES EXPECTED...AND RELATIVELY LOW SNOW/WATER RATIO VALUES BELOW 10/1...ANY SNOW ACCUMULATION SHOULD GENERALLY REMAIN AT OR BELOW 2 INCHES. THERE MAY ALSO BE SOME ADDITIONAL LAKE ENHANCED SNOW INTO NW UPPER MI LATE AS WNW WINDS STRENGTHEN BEHIND THE LOW. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 337 AM EDT SUN OCT 20 2013 AN ACTIVE WEATHER PATTERN IS IN STORE FOR THE UPPER GREAT LAKES REGION FOR THE UPCOMING WORK WEEK. THE UPPER TROUGH THAT IS AFFECTING THE UPPER GREAT LAKES WILL BE RE-ENFORCED BY A SHORTWAVE CURRENTLY DROPPING SOUTH OVER LAKE WINNIPEG. THIS WAVE WILL CATCH UP WITH THE SURFACE LOW AND SHORTWAVE IN SOUTHERN MINNESOTA (CURRENTLY IN WESTERN NORTH DAKOTA) AND INTENSIFY THE LOW TONIGHT AS THE SHORTWAVES PHASE...CAUSING THE LOW TO LIFT NORTHEAST AND OVER EASTERN LAKE SUPERIOR BY 12Z MONDAY. MODELS SEEM TO BE COMING INTO BETTER AGREEMENT ON THE TRACK/INTENSITY OF THE LOW AS IT MOVES NORTH FROM EASTERN LAKE SUPERIOR ON MONDAY...WHILE LEAVING A SURFACE TROUGH BACK OVER THE LAKE THROUGH MONDAY NIGHT. EXPECT THE INITIAL SURGE OF PRECIPITATION THAT MOVES THROUGH SUNDAY AFTERNOON/NIGHT TO BE PUSHING NORTHEAST OF UPPER MICHIGAN. THUS...WITH COLD AIR SURGING EAST ACROSS UPPER MICHIGAN UNDER THE GUSTY WESTERLY FLOW...EXPECT THE MAIN WEATHER TO START MONDAY TO BE WESTERLY WIND LAKE ENHANCED PRECIPITATION. THIS IS DUE TO 850MB TEMPS FALLING TO -8C OVER WESTERN UPPER MICHIGAN BY 18Z MONDAY. WILL HIGHLIGHT THE HIGHEST POPS OVER THE HIGHER TERRAIN FROM THE KEWEENAW THROUGH THE GOGEBIC RANGE AND ALSO OVER THE HURON MOUNTAINS. WESTERLY WINDS LOOK TO BACK SLIGHTLY IN THE AFTERNOON AHEAD OF TROUGH DROPPING SOUTH ACROSS WESTERN LAKE SUPERIOR DURING THE LATE AFTERNOON. THIS MAY CAUSE THE BEST PRECIPITATION TO BE FOCUSED MORE OVER THE KEWEENAW DURING THE AFTERNOON. THEREFORE...DID OPT TO TRIM POP/QPF AMOUNTS OVER GOGEBIC/ONTONAGON COUNTIES SOME DURING THE AFTERNOON HOURS. SINCE WETBULB ZERO VALUES FALL OVER THE WEST AS THE COLD AIR SURGES EAST ACROSS THE U.P. EXPECT PRECIP TO FALL AS SNOW OVER THE WEST...BUT COULD MIX WITH RAIN AT TIMES NEAR LAKE SUPERIOR. SNOWFALL AMOUNTS DURING THE MORNING AND MOST OF THE AFTERNOON SHOULD BE LIGHT...WITH LOCATIONS SEEING AMOUNTS UNDER AN INCH. OVER THE REST OF UPPER MICHIGAN DURING THIS PERIOD...EXPECT BREEZY WESTERLY WINDS AND CLOUDY CONDITIONS...BUT LITTLE TO NO PRECIPITATION IS EXPECTED. THE BEST OPPORTUNITY WOULD BE OVER THE EAST RIGHT ALONG THE LAKE SUPERIOR/MICHIGAN SHORELINES AS LAKE ENHANCED PRECIPITATION WILL TRY TO PARALLEL THOSE AREAS. THEN TOWARDS SUNSET...THE SURFACE TROUGH WILL DROP SOUTH ONTO THE WESTERN U.P. SHORELINE AND BRING AN ENHANCED AREA OF CONVERGENCE AND PRECIPITATION. EXPECT THERE TO BE MODERATE TO HEAVY PRECIPITATION AS THIS TROUGH SLIDES THROUGH THE WESTERN U.P. DURING THE EVENING HOURS AND THEN THROUGH CENTRAL UPPER MICHIGAN DURING THE OVERNIGHT HOURS. 850MB TEMPS WILL ACTUALLY WARM A COUPLE DEGREES BEHIND THE TROUGH...BUT THE DEEP MOISTURE AND CYCLONIC FLOW ON THE BACK SIDE OF THE SURFACE AND 850MB LOW...ALONG WITH UPSLOPE WINDS...WILL SUPPORT LAKE ENHANCED PRECIPITATION THROUGH A GOOD PORTION OF THE NIGHT OVER THE WESTERN CWA AND INTO TUESDAY MORNING OVER THE NORTH CENTRAL CWA. THE PRECIPITATION DURING THIS PERIOD SHOULD FALL AS SNOW EXCEPT FOR LOCATIONS RIGHT ALONG THE LAKE SUPERIOR SHORELINE WHERE THE NORTH-NORTHWEST WINDS WOULD PRODUCE SOME HEAT TRANSFER FROM THE LAKE AND LEAD TO SOME RAIN/SNOW MIX. AS FOR RATIOS/AMOUNTS...THINKING THE SNOW RATIOS WILL BE AROUND OR JUST BELOW 10-1 WITH THE BEST FORCING BEING BELOW THE DGZ AND SNOW FLAKES FALLING FROM ALOFT CLUMPING TOGETHER AS THEY REACH THE STRONG UPWARD MOTION NEAR THE SURFACE. AS FOR QPF AMOUNTS...HPC INDICATES NAM IS THE COLDER SOLUTION IN THE MID LEVELS (BY AROUND 2C) BEHIND THE LOW...WHICH MAY BE PART OF THE REASON IT IS MUCH HIGHER ON QPF AMOUNTS WITH THE LAKE ENHANCED SNOW BEHIND THE TROUGH. SINCE THE HIGHER RESOLUTION OF THE NAM AND 4KM NEST PICK UP THE TERRAIN ENHANCEMENT...DID BLEND THAT WITH THE PREFERRED WARMER AND COARSER MODELS FOR QPF MONDAY AFTERNOON THROUGH TUESDAY MORNING. THIS CREATES 24HR VALUES OF 0.5-0.75IN FROM IRONWOOD THROUGH THE KEWEENAW AND ALSO OVER THE WESTERN SIDE OF THE HURON MOUNTAINS. AT 10-1 SLR VALUE...SNOWFALL AMOUNTS IN THE 3-6 INCH RANGE SEEM REASONABLE IN THOSE AREAS AFTER FACTORING SOME MELTING INITIALLY ON MONDAY WHEN THE SNOWFALL RATES ARE LIGHTER. THAT SEEMS TO FIT IN WITH OUR ADVISORY CRITERIA AND WILL LIKELY END UP JUST UNDER THE 6INCH IN 12HR MARK FOR WARNINGS. CIPS TOP ANALOGS (BASED OFF THE SLIGHTLY COLDER NAM SOLUTION) SHOW MEAN SNOWFALL AMOUNTS OF 4-8 INCHES OF A 72HR PERIOD AND PROBABILITIES OF SEEING 6IN OF SNOW AROUND 60 PERCENT. THINK THE FORECAST MATCHES UP PRETTY WELL WITH THAT IDEA (ALONG WITH HPC GUIDANCE) AND WILL CONTINUE TO HIGHLIGHT THIS MEASUREABLE SNOW EVENT IN THE HWO AND ISSUE AN SPS TO HIGHTEN THE AWARENESS. SURFACE TROUGH WILL QUICKLY SHIFT EAST OF THE AREA ON TUESDAY...AS AN AREA OF HIGH PRESSURE SLIDES INTO THE NORTHERN PLAINS. EXPECT A DIMINISHING PRECIPITATION TREND FROM WEST TO EAST ACROSS THE CWA WITH THE DEEPER MOISTURE DEPARTING. THROUGH THE REST OF THE WEEK...EXPECT NORTHWESTERLY FLOW TO BE IN PLACE AS THE LOW SITS OVER QUEBEC AND A SERIES OF HIGHS DROP SOUTHEAST THROUGH THE NORTHERN PLAINS. 850MB TEMPS THROUGH THE REST OF THE PERIOD SHOULD BE RIGHT AROUND -8C WHICH LEADS TO PLENTY OF LAKE INSTABILITY. WILL CONTINUE TO HIGHLIGHT CHANCE POPS OR HIGHER IN THE TRADITIONAL NORTHWEST FLOW LOCATIONS THROUGH FRIDAY. HIGHEST POPS AND POTENTIAL FOR ACCUMULATION SNOWFALL WILL BE OVER THE EASTERN U.P. WITH THE LONGER FETCH AND CLOSER PROXIMITY TO THE BETTER MOISTURE UNDER THE UPPER LOW. THERE WILL BE A COUPLE BRIEF PERIODS WHERE THE LAKE EFFECT PRECIPITATION WILL PICKUP AS WEAK SHORTWAVES AND BETTER MOISTURE SWEEP THROUGH. CIPS TOP ANALOGS FOR THE MID WEEK PERIOD UNDER PERSISTENT LAKE EFFECT SNOWFALL SHOWS PROBABILITY FOR 4IN OF SNOW IN A 72HR PERIOD BEING AROUND 60 PERCENT IN THE TRADITIONAL FAVORED NORTHWEST FLOW LOCATIONS. BEING THAT IS OVER A 3 DAY PERIOD...THING THOSE VALUES ARE REASONABLE WITH LIGHT ACCUMULATIONS OCCURRING THROUGH THE END OF THE WORK WEEK. THE UPPER TROUGHS INFLUENCE ON THE UPPER GREAT LAKES LOOKS TO WEAKEN THIS WEEKEND AS IT SHIFTS EAST INTO THE NEW ENGLAND STATES. BUT ANOTHER SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE ROCKIES WILL TRY TO MOVE INTO THE AREA FOR THE SECOND HALF OF THE WEEKEND. WILL JUST GO WITH A GENERAL CONSENSUS AND HAVE CHANCE POPS WITH TEMPERATURES REMAINING BELOW NORMAL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 129 AM EDT SUN OCT 20 2013 WITH AN UPSLOPE W WIND COMPONENT AND FAIRLY MOIST/CHILLY AIRMASS FLOWING OVER THE RELATIVELY WARM WATERS OF WRN LK SUP...SOME LO CLDS AND AT LEAST OCNL MVFR CIGS WL IMPACT IWD AND ESPECIALLY CMX THRU MUCH OF THE NGT. DOWNSLOPE NATURE OF THE FLOW SHOULD MAINTAIN VFR CONDITIONS AT SAW. ARRIVAL OF WEAK HI PRES RDG SHOULD BRING VFR WX TO ALL THE SITES FOR MUCH OF THE DAY SUN...BUT THICKER CLDS/RA WL ARRIVE SW TO NE SUN AFTN/EVNG AHEAD OF LO PRES MOVING THRU THE UPR LKS. EXPECT CONDITIONS TO DETERIORATE TO MVFR AT ALL 3 SITES AND EVEN IFR AT IWD UNDER STEADY RA WITH UPSLOPE N WIND. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 510 AM EDT SUN OCT 20 2013 LOW PRESSURE MOVEING OUT OF THE DAKOTAS WILL BEGIN TO INTENSIFY OVER THE UPPER MISSISSIPPI VALLEY TODAY AND THEN MOVE THROUGH THE UPPER GREAT LAKES TONIGHT AND MONDAY. AS THIS OCCURS...WINDS WILL STRENGTHEN ACROSS THE LAKE...FIRST OUT OF THE SOUTH TO SOUTHEAST AHEAD OF THE LOW THIS EVENING AND THEN OUT OF THE WEST BEHIND THE LOW LATE TONIGHT INTO MONDAY. THERE STILL ARE SOME DIFFERENCES IN THE EXACT TRACK AND STRENGTH OF THE LOW AS IT MOVES ACROSS LAKE SUPERIOR ON MONDAY...SO WIND SPEED/DIRECTIONS ARE STILL UNCERTAIN. AT THIS TIME...IT APPEARS THE STRONGEST WINDS WILL BE BEHIND THE LOW ON MONDAY AND MONDAY NIGHT...WHEN WEST GALES TO 35-40KTS VEERING TO THE NORTH ARE EXPECTED. ONCE THE LOW DEPARTS THE AREA...EXPECT NORTHWESTERLY WINDS UP TO 25KTS TO REMAIN OVER LAKE SUPERIOR INTO WEDNESDAY. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY AFTERNOON FOR LSZ265>267. GALE WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING FOR LSZ264. GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY MORNING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
338 AM EDT SUN OCT 20 2013 .SYNOPSIS... ISSUED AT 335 AM EDT SUN OCT 20 2013 COOL WEATHER WITH PERIODS OF LAKE EFFECT SHOWERS WILL CONTINUE INTO NEXT WEEK...AS A BROAD TROUGH OF LOW PRESSURE REMAINS OVER THE GREAT LAKES. EVEN COLDER AIR WILL ENGULF THE GREAT LAKES AND UPPER MIDWEST BY MONDAY...AS ANOTHER WEAK STORM SYSTEM EXITS NORTHEAST INTO QUEBEC EARLY IN THE WORK WEEK. TEMPERATURES MAY GET COLD ENOUGH TO BRING THE FIRST SNOWFALL OF THE SEASON...ESPECIALLY TO INTERIOR SECTIONS OF EASTERN UPPER AND NORTHERN LOWER MICHIGAN. && .SHORT TERM...(TODAY THROUGH TONIGHT) ISSUED AT 335 AM EDT SUN OCT 20 2013 MUCH DISCUSSED DEEP TROUGHING CONTINUES TO DOMINATE GREAT LAKES WEATHER AT THIS EARLY HOUR...DOWNSTREAM OF EQUALLY IMPRESSIVE RIDGING POCKING UP AND BEYOND THE NORTHWEST TERRITORIES. SUBTLE WAVE TRAVERSING WITHIN THIS FLOW...NOW IN THE PROCESS OF FURTHER DEAMPLIFYING AND CUTTING ACROSS THE NORTHERN LAKES. THIS...COMBINED WITH STILL MORE THAN SUPPORTIVE OVER-WATER INSTABILITY (H8 TEMPERATURES RIGHT AROUND -2C PER HIGH RES RAP AND 00Z SOUNDING ANALYSIS)...CONTINUES TO KICK OFF LAKE ENHANCED RAIN SHOWERS OFF NORTHERN LAKE MICHIGAN (EVEN HAD SOME LEGITIMATE SNOWFLAKES MIX IN WITH THE RAIN HERE ON TOP OF THE HILL). OTHERWISE...A RATHER QUIET AND TOUCH CHILLY NIGHT...WITH CURRENT READINGS MAINLY IN THE 30S AND LOWER 40S. MAIN SYSTEM OF INTEREST THROUGH THE SHORT TERM IS WELL DEFINED SHORTWAVE/VORT LOBE DROPPING STRAIGHT SOUTH THROUGH CENTRAL MANITOBA. THIS SYSTEM WILL DRUM UP A RATHER RESPECTABLE AREA OF LOW PRESSURE TONIGHT AS IT DROPS INTO MINNESOTA. GOOD MID LEVEL SUPPORT AND LOW LEVEL ENERGY SUPPLIED BY WARM LAKE WATERS WILL HELP DEEPEN THIS SURFACE LOW AS IT MOVES UP INTO EASTERN LAKE SUPERIOR BY MONDAY MORNING. THIS SYSTEM WILL BRING MORE WIDESPREAD RAINS HEADING INTO TONIGHT...AND PERHAPS A GALE EVENT ON PARTS OF THE BIG WATERS. SHORT TERM FORECAST CONCERNS CENTER ON ADDRESSING THE IMPACTS OF THIS SYSTEM. BY AND LARGE...A RATHER NON-EVENTFUL WEATHER DAY EXPECTED TODAY. CURRENT OVERHEAD WAVE WILL HAVE EXITED STAGE RIGHT BY SUNRISE...LEAVING PURE LAKE PROCESSES FOR ANY ADDITIONAL SHOWER DEVELOPMENT THROUGH MID AFTERNOON. EXPECT THERE WILL BE SOME ONGOING TO START THE DAY...ESPECIALLY ALONG THE NORTHWEST LOWER COASTLINE WHERE WIND CONVERGENCE WILL BE MAXIMIZED. LAKE PROCESSES WILL BE A DOWNWARD ONE HEADING THROUGH THE DAY AS WINDS BACK SOUTHERLY AND WEAK MID LEVEL RIDGING BUILDS OVERHEAD. ATTENTION LATE THIS AFTERNOON INTO THE OVERNIGHT TURNS TO STRONG WAA RESPONSE AHEAD OF EARLIER MENTIONED DEEPENING SURFACE LOW. RATHER IMPRESSIVE ISENTROPIC UPGLIDE SIGNATURE VIA FORCED ASCENT ON NOSE OF 40+ KNOT LOW LEVEL JET...WITH WELL OVER HALF INCH PWATS ALSO SURGING NORTH INTO THE AREA WITH THIS JET. ABOVE LOOKS TO KICK OFF A RATHER LARGE AREA OF RAIN...WHICH WILL SPREAD RAPIDLY NORTHEAST ACROSS OUR AREA LATE THIS AFTERNOON INTO THIS EVENING. PER FULL 00Z GUIDANCE ANALYSIS...MAY AMP UP RAIN CHANCES SOME SOUTHWEST THIRD OF THE AREA AFTER 21Z TODAY...WITH INHERITED CATEGORICAL WORDING INTO THIS EVENING LOOKING GREAT. DRY SLOT PUNCHES IN FROM THE SOUTHWEST THROUGH THE OVERNIGHT...LIKELY ABRUPTLY ENDING RAINS AS IT DOES SO. MAY SEE SOME LAKE SHOWERS ATTEMPT TO FIRE FAR NORTHERN LAKE MICHIGAN TOWARDS MORNING WHERE MOISTURE WILL REMAIN DEEPER AND POST-COLD FRONT CAA REGIME ONCE AGAIN DROPS H8 READINGS TO JUST BELOW 0C. && .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 335 AM EDT SUN OCT 20 2013 CLASSIC LATE AUTUMN WX WILL REMAIN IN PLACE FOR THE UPCOMING WEEK...A BIT AHEAD OF SCHEDULE. PLENTY OF UPPER TROFFING WILL REMAIN IN PLACE IN CENTRAL CANADA AND ADJOINING PARTS OF THE STATES. THE LOWEST HEIGHTS WILL BE OVERHEAD MONDAY EVENING...AS AN UPPER LOW CROSSES EASTERN SUPERIOR. HOWEVER...HEIGHT RECOVERY AFTER THAT LOW EJECTS TO THE NE WILL BE ANEMIC. THAT WILL MAINTAIN MIXED PRECIP AS A SIGNIFICANT FORECAST CONCERN...ESPECIALLY DURING THE LATE NIGHT/ EARLY MORNING HOURS. PRECIP TRENDS ARE THE MAIN CONCERN. MONDAY...500MB LOW MOVES FROM INL TO MQT. 999MB SURFACE LOW OVER EASTERN SUPERIOR WILL LIFT NE TO SSW OF JAMES BAY...WITH A NEW LOW SPINNING UP ALONG A SECONDARY COLD FRONT IN CENTRAL SUPERIOR DURING THE AFTERNOON. THE BACK EDGE OF THE WARM CONVEYOR BELT WILL BE ABOUT TO EXIT NE LOWER MI AT 12Z...WITH DRIER MID LEVEL AIR IN THE PROCESS OF POURING INTO NORTHERN LOWER. HOWEVER...OVERLAKE INSTABILITY WILL BE INCREASING CONSIDERABLY AS COLDER LOW LEVEL AIR POURS IN. 850MB TEMPS OVER NORTHERN LAKE MI WILL NEAR -6C BY 18Z...-8C BY 00Z. MEANWHILE...EASTERN UPPER WILL REMAIN ON THE SOUTHERN PERIPHERY OF THE DEEPER WRAPAROUND MOISTURE. COULD STILL BE SOME FRONTAL SHRA IN FAR EASTERN SECTIONS TO START THE MORNING. SCT SHRA WILL GET GOING IN WSW-FLOW AREAS (ESPECIALLY FROM LEELANAU NORTHWARD) DURING THE MORNING...AS WELL AS IN EASTERN UPPER. THESE COULD BECOME MORE NUMEROUS IN THE AFTERNOON...AS INSTABILITY INCREASES (DELTA T/S IN THE LOWER 20S) AND THE CORE OF THE DRY SLOT MOVES EAST. 1000-850MB WINDS WILL VEER TO THE WEST DURING THE AFTERNOON...WITH INVERSION HEIGHTS A REASONABLY HEALTHY 6-7K FT. WILL INTRODUCE A SMALL CHANCE FOR A MIX VERY LATE IN THE DAY IN THE INTERIOR OF EASTERN UPPER...WHERE THE SURFACE-BASED MELTING LAYER IS NARROWING BELOW 1K FT. MAX TEMPS IN THE 40S (TO LOWER 50S NE LOWER) AND EARLY...WITH FALLING TEMPS IN THE PM. BRISK TO WINDY...ESPECIALLY NEAR LAKE MI. MON NIGHT/TUESDAY...UPPER LOW WILL GRADUALLY LIFT OUT TOWARD JAMES BAY...THOUGH WITH A SUBSTANTIAL SHORTWAVE ROUNDING IT/S SOUTHERN FLANK LATE MONDAY NIGHT. THAT WILL DRIVE THE SECONDARY FRONT INTO EASTERN UPPER MI LATE MONDAY NIGHT...AND ACROSS THE REST OF THE FORECAST AREA ON TUESDAY. 1000-850MB WINDS WILL BRIEFLY BACK MORE WSW AGAIN JUST AHEAD OF THIS TROF...ALLOWING THE INITIAL 850MB THERMAL TROF TO MOVE EAST AND BOOSTING 850MB TEMPS TO -5C. WINDS RAPIDLY VEER NW BEHIND THE TROF...AND COLD ADVECTION RESUMES. AFTER CONTINUED LOW-END-ISH LAKE EFFECT MONDAY EVENING (THOUGH WITH MORE SNOW MIXING IN AS DIURNAL HEATING IS LOST)...PRECIP WILL SUBSTANTIALLY RAMP UP OVERNIGHT AS THE SECONDARY FRONT AND SHARP 1000-850MB CONVERGENCE ARRIVES. SLUSHY ACCUMS UP TO AN INCH SEEM A DISTINCT POSSIBILITY MONDAY NIGHT NEAR GLR/BOYNE CITY/MANCELONA... AND IN WESTERN CHIP. TUESDAY WILL SEE A WOBBLY NW FLOW...BUT WITH MID-LEVEL DRYING/SUBSIDENCE AS THE VORT LOBE MOVES EAST. SOME LAKE EFFECT WILL CONTINUE...ESPECIALLY IN THE MORNING...WITH DISRUPTIVE DIURNAL HEATING DISORGANIZING THINGS IN THE PM. SOME SLOPPY LIGHT ACCUMS ARE AGAIN POSSIBLE IN THE MOST FAVORED AREAS OF BOTH PENINSULAS IN THE MORNING. MIN TEMPS WITHIN A FEW DEGREES OF 30F. MAX TEMPS NEAR 40F TO THE MID 40S. AND IT WILL REMAIN BRISK TO WINDY. REST OF THE FORECAST...FEW CHANGES NEEDED...AS COLD AND SHOWERY WX WILL PERSIST AS CURRENTLY FORECAST. NEW ECMWF IS FLAT-OUT COLD STRAIGHT THRU 240HRS. (PROBABLY BEST FOR MOTHER NATURE TO GET THIS OUT OF HER SYSTEM NOW.) && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1100 PM EDT SAT OCT 19 2013 SCT/NMRS LAKE ENHANCED RAIN SHOWERS WILL CONTINUE TO IMPACT NRN LWR MICHIGAN TAF SITES THRU SUNDAY NIGHT THANKS TO DEEP CYCLONIC FLOW...COLD AIR ACTIVATING THE LAKES AND AMPLE LOW LEVEL MOISTURE. OVERALL...CIGS WILL REMAIN LOW VFR...BUT MAY BRIEFLY DROP TO HIGH MVFR WITHIN SOME OF THE HEAVIER SHOWER ACTIVITY. WESTERLY WINDS UNDER 10 KTS TONIGHT WILL SHIFT TO THE S/SW ON SUNDAY AHEAD OF DEEPENING LOW PRESSURE SLIDING INTO THE UPPER MISSISSIPPI VALLEY. && .MARINE... ISSUED AT 335 AM EDT SUN OCT 20 2013 RELATIVELY LIGHT WINDS THIS MORNING GIVES WAY TO INCREASINGLY GUSTY SOUTH FLOW LATER THIS AFTERNOON...AND ESPECIALLY TONIGHT...AS LOW PRESSURE INTENSIFIES AND PUSHES INTO EASTERN LAKE SUPERIOR BY MONDAY MORNING. TIGHTENING PRESSURE GRADIENT AND ONSET OF IMPRESSIVE SURGE OF CAA WILL LEAD TO VERY GUSTY WEST TO SOUTHWEST WINDS DURING THE DAY MONDAY...WITH THE STRONGEST WINDS EXPECTED OVER NORTHERN LAKE MICHIGAN. GALE FORCE WIND GUSTS APPEAR INCREASINGLY LIKELY...RESULTING IN AN UPGRADE TO INHERITED NORTHERN LAKE MICHIGAN GALE WATCH TO A WARNING. IN ADDITION...WIND GUST MAY REACH GALE FORCE ACROSS WHITEFISH BAY AND THE ST. MARYS RIVER LATER MONDAY MORNING THROUGH THE AFTERNOON. CONFIDENCE NOT HIGH ENOUGH TO WARRANT A GALE WARNING...BUT ENOUGH CONCERN TO HOIST A GALE WATCH FOR THESE AREAS. ADDITIONAL SCA/S WILL LIKELY BE NEEDED FOR OTHER NEARSHORE ZONES...BUT WILL FOCUS ON GALE CONDITIONS AND PUNT ADVISORY ISSUANCES TO FUTURE FORECAST SHIFTS. WELCOME TO FALL ON THE GREAT LAKES! && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LHZ345. LM...GALE WARNING FROM 5 AM MONDAY TO 11 AM EDT TUESDAY FOR LMZ341- 342-344>346. LS...GALE WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR LSZ321- 322. && $$ SYNOPSIS...JZ SHORT TERM...MB LONG TERM...JZ AVIATION...MR MARINE...MB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
711 PM CDT MON OCT 21 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 325 PM CDT MON OCT 21 2013 TONIGHT THRU TUESDAY...COLD PATTERN WILL REMAIN IN PLACE THRU TMRW AS A DEEP UPPER LEVEL LOW WITHIN A LONGWAVE TROUGH OVER ERN CANADA DIPS INTO THE GREAT LAKES. THE LOW WILL SHIFT TO THE E...PUTTING PRONOUNCED NW FLOW OVER THE AREA...AHEAD OF A LARGE LONGWAVE RIDGE OVER THE WRN CONUS. WITHIN THE FLOW OF THIS NW FLOW...A CLIPPER-TYPE LOW PRES SYSTEM WILL DRIVE SE FROM WRN CANADA THRU THE DAKOTAS ON ITS WAY INTO IA/MO/IL. THE LOW LOOKS TO BE DISPLACED FAR ENOUGH TO THE S AND W SUCH THAT APPRECIABLE SNOWFALL WILL NOT BE AN ISSUE... SAVE FOR AN INCH OR SO FOR A COUPLE OF COUNTIES ALONG THE IA BORDER OVERNIGHT. THIS LOW WILL THEN QUICKLY SHIFT OFF WELL TO THE SE DURG THE DAY TMRW WHILE HIGH PRES MOVES IN BEHIND THE LOW FOR TMRW. TEMPS WILL CONTINUE TO RUN ABOUT 5-10 DEGREES BELOW NORMAL...WITH LOWS TONIGHT DROPPING INTO THE MID-UPR 20S. ALTHOUGH THE WFO MPX FROST/FREEZE PROGRAM HAS BEEN SUSPENDED FOR THE SEASON...IT IS WORTH NOTING THAT MOST LOCALES WILL RECEIVE THE FIRST HARD FREEZE OF THE SEASON TONIGHT. HIGHS TMRW WILL THEN ONLY REACH THE LWR 40S. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 325 PM CDT MON OCT 21 2013 THE SECOND SYSTEM IS NEARLY ON THE SAME TRACK AS TUESDAY ALBERTA TYPE CLIPPER AS IT MOVES ACROSS THE MIDWEST...AND MAINLY AFFECTING FAR SW/SC MN WEDNESDAY MORNING. RESIDUAL MOISTURE CONTINUES ON THURSDAY IN THE FAVORED DENDRITIC ZONE ACROSS THE REGION. HOWEVER MOISTURE DEPTH REMAINS SHALLOW IN THIS ZONE WHICH WILL LEAD TO OCCASIONAL FLURRIES/SPRINKLES AT BEST. AFTER THURSDAY...THERE WILL BE A SLIGHT CHG IN THE WEATHER PATTERN AS WARMER AIR BEGINS TO MOVE ACROSS THE PLAINS...AND INTO THE UPPER MIDWEST AS THE FLOW PATTERN ALOFT BECOMES MORE WEST/SW BY THIS WEEKEND. AS THIS PATTERN DEVELOPS...MOST OF THE ENERGY AND MOISTURE WILL LIFT ACROSS CANADA AND THE NORTHERN GREAT LAKES...KEEPING OUR REGION DRY...AND PERHAPS SLIGHTLY NEAR OR ABV NORMAL BY SAT/SUN. AT THE SAME TYPE WITH THE WARMER FLOW DEVELOPING...A STORM SYSTEM IS EXPECTED TO ORGANIZE ACROSS THE NORTHERN ROCKIES...THEN DIVE SOUTH INTO THE SOUTHERN ROCKIES EARLY NEXT WEEK. ALTHOUGH THE GFS/EC HAVE ONLY DEVELOPED THIS TYPE OF WEATHER PATTERN CHG IN THE PAST FEW MODEL RUNS...THIS TYPE OF PATTERN IS MORE CONDUCIVE OF A STRONG STORM SYSTEM TO DEVELOP ACROSS THE PLAINS...AND POSSIBLY AFFECTING THE UPPER MIDWEST/GREAT LAKES REGION BY THE MIDDLE OF NEXT WEEK. FORECASTERS NEED TO MONITOR TRENDS ON THIS TYPE OF LONG WAVE PATTERN CHG...AND HOW CRITICAL THICKNESS VALUES ORIENT ALONG THE THERMAL BOUNDARY. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 711 PM CDT MON OCT 21 2013 CEILING GENERALLY 040-050 NE OF I-94 FROM AXN TO MSP THEN SE TO RGK. LATEST RAP DOES IMPLY SCATTERED CLOUDS EARLY THIS EVENING AT AXN/STC/MSP...BUT SLOW MOVING SATELLITE TRENDS SUGGEST TAKING A MORE CONSERVATIVE COURSE AT AXN/STC. WILL NOT GO SCATTERED AT AXN/STC UNTIL LATER THIS EVENING. NEXT SURGE OF BKN040-050 SHOULD ARRIVE TUESDAY AFTER 15Z IN NNW FLOW. AM A LITTLE SKEPTICAL OF SEEING MUCH OVC LATE TONIGHT INTO TUESDAY MORNING SINCE LOW-MID LEVEL HEIGHTS LOOK TO BE RISING EVER SO SLIGHTLY THROUGH 15Z...THEN SOME CYCLONIC FLOW RETURNS. THUS WILL PROBABLY SEE SOME BROKEN040 DEVELOPING AROUND 16Z OR SO. PROFILES AS VIEWED IN BUFKIT INDICATE SOME POTENTIAL FOR GUSTS OF 15-20 KTS TOMORROW MIDDAY AMIDST LOW LEVEL ADIABATIC PROFILES. MEANWHILE...IN SW MN...CLIPPER MENTIONED IN SHORT-TERM WILL LIKELY PASS FAR ENOUGH WEST AND SOUTH OF KRWF TO ONLY BRING SOME OVC MID LEVEL CLOUDS. LIGHT SNOW SHOULD BE FARTHER SOUTH AND WEST. FEW FLURRIES AT BEST AT KRWF. KMSP...BROKEN CEILINGS AROUND 045 SHOULD PERSIST MUCH OF THE NIGHT OVER THE NORTHEAST TWIN CITIES METRO...JUST NORTH AND NORTHEAST OF THE AIRFIELD. NEXT SURGE OF BKN040 MOST LIKELY WILL NOT ARRIVE UNTIL TUESDAY 15Z OR SO. LOOKS LIKE THERE WILL BE SOME GUSTS TOMORROW AROUND 15-18 KTS DUE TO LOW LEVEL ADIABATIC TEMPERATURE PROFILES. /OUTLOOK FOR KMSP/ WED...VFR. SW WIND LESS THAN 5 KT BECMG NW 5-10 KT. THU...VFR. NW WIND 10-15 KT. FRI...VFR. SW WIND 10 KT INCRG TO 15 TO 20 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JPC LONG TERM...JLT AVIATION...TDK
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
131 PM CDT SUN OCT 20 2013 .SHORT/LONG TERM...(TODAY THROUGH SATURDAY) ISSUED AT 433 AM CDT SUN OCT 20 2013 PERSISTENT NORTHWEST FLOW WILL REMAIN IN TACT THROUGHOUT THE PERIOD...LEADING TO BELOW NORMAL TEMPERATURES AND PERIODIC CHANCES FOR LIGHT PRECIP. GIVEN THE COLD AIR EXPECTED TO BE IN PLACE...WILL SEE THE POTENTIAL FOR FROZEN PRECIP CARRY ON THROUGH NEXT WEEK. ARGUABLY THE MOST INTRIGUING FEATURE IN THE EXTENDED IS THE CLIPPER SYSTEM CURRENTLY APPROACHING THE UPPER MIDWEST. THE LATEST HIRES MODELS PORTRAY MORE OF A SOUTHERLY TRACK...SO HAVE BROUGHT THE HIGHEST POPS AND QPF SOUTH TO REFLECT THIS TREND. HOWEVER...BUFR FORECAST SOUNDINGS OFF THE RAP ONLY HAVE AROUND AN INCH OF SNOW AT MORA...AND BRAINERD...WITH LESS AT ALEXANDRIA AND ST CLOUD. THE NAM IS CONTINUES TO ADVERTISE 4 INCHES AT MORA...BUT THIS IS LIKELY OVERDONE CONSIDERING THAT ACCORDING TO THE NAM AS OF 5AM 1-2 INCHES SHOULD HAVE ALREADY FALLEN AT FARGO..AND THEY HAVE YET TO RECEIVE ANY SNOW. THE MAIN REASON FOR THE SLOW CHANGEOVER SEEMS TO BE THE LACK OF STRONG FGEN AND FOCUSED VERTICAL MOTION IN THE WAA REGIME...RATHER GRADUAL ISENTROPIC ASCENT WAS THE DRIVING FORCE BEHIND THE PRECIP. THROUGHOUT THE MORNING HOURS...THE NAM DOES INCREASE THE FGEN FORCING...WHILE THE RAP IS WEAKER. AFTER WEEDING THROUGH THE DIFFERENT SCENARIOS...DO NOT HAVE THE CONFIDENCE IN ANY SNOWFALL AMOUNTS EXCEEDING 3 INCHES DESPITE THE SOUTHERLY SHIFT IN QPF. RATHER SHOULD SEE A MODEST BAND OF SNOW TRACK NORTH OF I-94...WITH PERHAPS AN INCH OR 2 ON GRASSY SURFACES THIS MORNING...BEFORE TRANSITIONING TO MORE OF RAIN/SNOW OR EVEN ALL RAIN MIX LATER THIS AFTERNOON AS 1)THE BOUNDARY LAYER WARMS...AND 2) WE LOSE THE DEEP SATURATION AND TRANSITION TO MORE OF LIGHT RAIN/DRIZZLE SCENARIO. BRISK NORTHWEST WINDS WILL FOLLOW ONCE THIS SYSTEM MOVES EASTWARD AS COOLER AIR AS EVIDENT BY THE -7 TO -10C H850 TEMPS ADVECT ACROSS THE REGION SUNDAY NIGHT INTO MONDAY. THE NORTHWEST FLOW WILL PERSIST ACROSS THE REGION...WITH A FEW SHORTWAVES TRACKING DOWN THE POLEWARD SIDE OF THE JET. THESE WILL INDUCE LOW LEVEL CIRCULATIONS...THE NEXT OF WHICH IS EXPECTED TO TRACK SOUTHWEST OF THE CWA ALONG THE MISSOURI RIVER VALLEY MONDAY NIGHT INTO TUESDAY. COLD AIR WILL AGAIN BE REINFORCED BEHIND THIS SYSTEM...WILL NO WARM UP POTENTIAL IN SIGHT UNTIL PERHAPS THE END OF THE WEEK AS ANOTHER WAVE MOVES ACROSS THE REGION. DEPENDING ON THE TRACK OF THIS SYSTEM...THE UPPER MIDWEST COULD SEE ONE DAY OF WARMER TEMPERATURES...BUT THE GUIDANCE IS CONSISTENT THAT THIS WILL BE SHORT LIVED AS ANOTHER ARCTIC AIRMASS WILL FOLLOW BEHIND THIS PASSING WAVE. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 1259 PM CDT SUN OCT 20 2013 THIS TAF CYCLE HAS PROVED DIFFICULT...WITH A FEW AMENDMENTS/ CORRECTIONS REQUIRED WITHIN MINUTES OF THE INITIAL SET BEING ISSUED. A DRY SLOT ACROSS SOUTH CENTRAL MN HAS BROUGHT VFR CONDITIONS THERE TEMPORARILY...BUT IT IS ALREADY BEGINNING TO FILL BACK IN WITH CLOUDS ON THE BACKSIDE OF THE LOW WHICH ARE ACCELERATING EASTWARD. CIGS WITHIN THIS AREA OF WRAP AROUND CLOUDS ARE SOLIDLY MVFR...WITH SOME LOCATIONS AS LOW AS IFR...PARTICULARLY OVER NORTHEASTERN SOUTH DAKOTA AND WEST CENTRAL MN. FURTHER EAST...SNOW CONTINUES ACROSS EAST CENTRAL MN WHERE VSBYS REMAIN LESS THAN 1 MILE. THE STEADY PRECIPITATION WILL TAPER OFF EARLY THIS AFTERNOON WITH THE TAF SITES BECOMING MAINLY SPORADIC -RA OR -DZ FOR THE REST OF THE AFTERNOON. CONFIDENCE REMAINS QUITE LOW WITH REGARD TO HOW LOW CIGS WILL BECOME THIS EVENING BEFORE DRIER AIR ARRIVES FROM EASTERN NORTH DAKOTA. MUCH OF THE GUIDANCE APPEARS TOO OPTIMISTIC GIVEN CURRENT CONDITIONS SO WILL CONTINUE THE TREND DOWNWARD INTO EARLY EVENING. THE DRIER AIR SHOULD ERODE THE LOWER CIGS OVERNIGHT AND MONDAY MORNING. KMSP...THE SHORT STINT OF VFR CIGS IS OVER FOR NOW. CIGS CONTINUE TO CRASH TO THE WEST WITH MVFR AND SUB 017 CIGS EXPECTED A LITTLE LATER THIS AFTERNOON. EVENTUALLY DRIER AIR WILL ERODE THE LOWER CIGS OVERNIGHT...BUT CONFIDENCE IS QUITE LOW AS TO WHEN THIS WILL OCCUR. /OUTLOOK FOR KMSP/ MON NIGHT...VFR. WINDS WNW 5-10 KTS. TUE...VFR WITH MVFR CIGS POSSIBLE EARLY. WINDS NW AT 10 KTS. WED...MVFR CIGS POSSIBLE. WINDS NW AT 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JRB LONG TERM...JRB AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
654 AM CDT SUN OCT 20 2013 .SHORT/LONG TERM...(TODAY THROUGH SATURDAY) ISSUED AT 433 AM CDT SUN OCT 20 2013 PERSISTENT NORTHWEST FLOW WILL REMAIN IN TACT THROUGHOUT THE PERIOD...LEADING TO BELOW NORMAL TEMPERATURES AND PERIODIC CHANCES FOR LIGHT PRECIP. GIVEN THE COLD AIR EXPECTED TO BE IN PLACE...WILL SEE THE POTENTIAL FOR FROZEN PRECIP CARRY ON THROUGH NEXT WEEK. ARGUABLY THE MOST INTRIGUING FEATURE IN THE EXTENDED IS THE CLIPPER SYSTEM CURRENTLY APPROACHING THE UPPER MIDWEST. THE LATEST HIRES MODELS PORTRAY MORE OF A SOUTHERLY TRACK...SO HAVE BROUGHT THE HIGHEST POPS AND QPF SOUTH TO REFLECT THIS TREND. HOWEVER...BUFR FORECAST SOUNDINGS OFF THE RAP ONLY HAVE AROUND AN INCH OF SNOW AT MORA...AND BRAINERD...WITH LESS AT ALEXANDRIA AND ST CLOUD. THE NAM IS CONTINUES TO ADVERTISE 4 INCHES AT MORA...BUT THIS IS LIKELY OVERDONE CONSIDERING THAT ACCORDING TO THE NAM AS OF 5AM 1-2 INCHES SHOULD HAVE ALREADY FALLEN AT FARGO..AND THEY HAVE YET TO RECEIVE ANY SNOW. THE MAIN REASON FOR THE SLOW CHANGEOVER SEEMS TO BE THE LACK OF STRONG FGEN AND FOCUSED VERTICAL MOTION IN THE WAA REGIME...RATHER GRADUAL ISENTROPIC ASCENT WAS THE DRIVING FORCE BEHIND THE PRECIP. THROUGHOUT THE MORNING HOURS...THE NAM DOES INCREASE THE FGEN FORCING...WHILE THE RAP IS WEAKER. AFTER WEEDING THROUGH THE DIFFERENT SCENARIOS...DO NOT HAVE THE CONFIDENCE IN ANY SNOWFALL AMOUNTS EXCEEDING 3 INCHES DESPITE THE SOUTHERLY SHIFT IN QPF. RATHER SHOULD SEE A MODEST BAND OF SNOW TRACK NORTH OF I-94...WITH PERHAPS AN INCH OR 2 ON GRASSY SURFACES THIS MORNING...BEFORE TRANSITIONING TO MORE OF RAIN/SNOW OR EVEN ALL RAIN MIX LATER THIS AFTERNOON AS 1)THE BOUNDARY LAYER WARMS...AND 2) WE LOSE THE DEEP SATURATION AND TRANSITION TO MORE OF LIGHT RAIN/DRIZZLE SCENARIO. BRISK NORTHWEST WINDS WILL FOLLOW ONCE THIS SYSTEM MOVES EASTWARD AS COOLER AIR AS EVIDENT BY THE -7 TO -10C H850 TEMPS ADVECT ACROSS THE REGION SUNDAY NIGHT INTO MONDAY. THE NORTHWEST FLOW WILL PERSIST ACROSS THE REGION...WITH A FEW SHORTWAVES TRACKING DOWN THE POLEWARD SIDE OF THE JET. THESE WILL INDUCE LOW LEVEL CIRCULATIONS...THE NEXT OF WHICH IS EXPECTED TO TRACK SOUTHWEST OF THE CWA ALONG THE MISSOURI RIVER VALLEY MONDAY NIGHT INTO TUESDAY. COLD AIR WILL AGAIN BE REINFORCED BEHIND THIS SYSTEM...WILL NO WARM UP POTENTIAL IN SIGHT UNTIL PERHAPS THE END OF THE WEEK AS ANOTHER WAVE MOVES ACROSS THE REGION. DEPENDING ON THE TRACK OF THIS SYSTEM...THE UPPER MIDWEST COULD SEE ONE DAY OF WARMER TEMPERATURES...BUT THE GUIDANCE IS CONSISTENT THAT THIS WILL BE SHORT LIVED AS ANOTHER ARCTIC AIRMASS WILL FOLLOW BEHIND THIS PASSING WAVE. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING) ISSUED AT 621 AM CDT SUN OCT 20 2013 A COMPLEX AND MESSY TAF PERIOD IS AHEAD AS A CLIPPER SYSTEM DIVES SOUTHEAST ACROSS SOUTHERN MINNESOTA TODAY. PRECIPITATION CONTINUES TO MOVE EAST AND IS NOW APPROACHING KMSP. IT SHOULD BEGIN AS SNOW...CHANGE QUICKLY TO RAIN WITH MAYBE SOME SNOW MIXED IN AT THE TAF SITES FOR AN HOUR OR SO THIS MORNING AS WELL AS SOME DRIZZLE. DONT REALLY HAVE STRONG UPWARD VERTICAL MOTION SO DO NOT EXPECT DYNAMIC COOLING OF ANY SORT TO FOUL UP THE PRECIPITATION TYPE. BOUNDARY LAYER TEMPS WARM THIS MORNING WITH WARM AIR ADVECTION IN PLACE AND THERMAL PROFILES SUPPORT A QUICK CHANGE FROM SNOW TO RAIN. QUICK PEEK AT THE KMPX SOUNDING SHOWS A LOT MORE MOISTURE ABOVE 700MB AS COMPARED TO LAST EVENINGS SOUNDING. HIGH RES MODELS INDICATE DRY AIR TO WORK IN FROM THE SOUTHWEST AFTER 20Z AND AS A RESULT PRECIP SHOULD END AROUND 20-21Z IN MOST AREAS...MAYBE SOME DRIZZLE CONTINUING AT AXN/STC AND OVER INTO WESTERN WISCONSIN. GUIDANCE WANTS TO RAISE CIGS TOO MUCH FOR THE EVENING AND OVERNIGHT HOURS. MUCH DRIER AIR COMES IN ALOFT HOWEVER THE LOWEST 4000 FEET OF THE ATMOSPHERE REMAIN QUITE MOIST SO WILL HOLD ON TO MVRF CIGS THROUGH THE PERIOD. WINDS WILL BE QUITE GUSTY AT AXN/RWF THIS AFTERNOON AND EARLY EVENING. KMSP...ONSET OF PRECIP WILL OCCUR BY 12Z AND THAT SHOULD BE SNOW PELLETS...SNOW AND OR DRIZZLE. AFTER 13Z WILL SEE A MIX AT TIMES OF RAIN AND SNOW AND ALL RAIN BY 14Z AS THE BOUNDARY LEVEL WARMS SLIGHTLY. WARM AIR ADVECTION PATTERN FEATURES A SLOW UPWARD ASCENT OF AIR HENCE THE OPPORTUNITIES FOR DRIZZLE OR LIGHT RAIN. BIGGEST UNCERTAINTY WILL BE CIGS TODAY THROUGH MONDAY MORNING. WAS OPTIMISTIC FOR TODAY AND PESSIMISTIC FOR THE OVERNIGHT HOURS AS COMPARED TO GUIDANCE. HOWEVER COULD EASILY SEE LOWER CIGS THIS MORNING AND AFTERNOON AND THAT WILL HAVE TO BE WATCHED CLOSELY AS THE WARM FRONT WILL BE JUST NORTH OF THE METRO AND MSP WILL BE SOMEWHERE BETWEEN THE IFR CIGS TO THE NORTH AND VFR OR MVFR CIGS TO THE SOUTH IN THE WARMER AIR. /OUTLOOK FOR KMSP/ MON...MVFR IN AM...VFR IN AFTERNOON. WINDS NW AT 10-15KT. TUE...VFR WITH MVFR CIGS POSSIBLE EARLY. WINDS NW AT 5-10 KTS. WED...MVFR CIGS POSSIBLE. WINDS W AT 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JRB LONG TERM...JRB AVIATION...DRL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
435 AM CDT SUN OCT 20 2013 .SHORT/LONG TERM...(TODAY THROUGH SATURDAY) ISSUED AT 433 AM CDT SUN OCT 20 2013 PERSISTENT NORTHWEST FLOW WILL REMAIN IN TACT THROUGHOUT THE PERIOD...LEADING TO BELOW NORMAL TEMPERATURES AND PERIODIC CHANCES FOR LIGHT PRECIP. GIVEN THE COLD AIR EXPECTED TO BE IN PLACE...WILL SEE THE POTENTIAL FOR FROZEN PRECIP CARRY ON THROUGH NEXT WEEK. ARGUABLY THE MOST INTRIGUING FEATURE IN THE EXTENDED IS THE CLIPPER SYSTEM CURRENTLY APPROACHING THE UPPER MIDWEST. THE LATEST HIRES MODELS PORTRAY MORE OF A SOUTHERLY TRACK...SO HAVE BROUGHT THE HIGHEST POPS AND QPF SOUTH TO REFLECT THIS TREND. HOWEVER...BUFR FORECAST SOUNDINGS OFF THE RAP ONLY HAVE AROUND AN INCH OF SNOW AT MORA...AND BRAINERD...WITH LESS AT ALEXANDRIA AND ST CLOUD. THE NAM IS CONTINUES TO ADVERTISE 4 INCHES AT MORA...BUT THIS IS LIKELY OVERDONE CONSIDERING THAT ACCORDING TO THE NAM AS OF 5AM 1-2 INCHES SHOULD HAVE ALREADY FALLEN AT FARGO..AND THEY HAVE YET TO RECEIVE ANY SNOW. THE MAIN REASON FOR THE SLOW CHANGEOVER SEEMS TO BE THE LACK OF STRONG FGEN AND FOCUSED VERTICAL MOTION IN THE WAA REGIME...RATHER GRADUAL ISENTROPIC ASCENT WAS THE DRIVING FORCE BEHIND THE PRECIP. THROUGHOUT THE MORNING HOURS...THE NAM DOES INCREASE THE FGEN FORCING...WHILE THE RAP IS WEAKER. AFTER WEEDING THROUGH THE DIFFERENT SCENARIOS...DO NOT HAVE THE CONFIDENCE IN ANY SNOWFALL AMOUNTS EXCEEDING 3 INCHES DESPITE THE SOUTHERLY SHIFT IN QPF. RATHER SHOULD SEE A MODEST BAND OF SNOW TRACK NORTH OF I-94...WITH PERHAPS AN INCH OR 2 ON GRASSY SURFACES THIS MORNING...BEFORE TRANSITIONING TO MORE OF RAIN/SNOW OR EVEN ALL RAIN MIX LATER THIS AFTERNOON AS 1)THE BOUNDARY LAYER WARMS...AND 2) WE LOSE THE DEEP SATURATION AND TRANSITION TO MORE OF LIGHT RAIN/DRIZZLE SCENARIO. BRISK NORTHWEST WINDS WILL FOLLOW ONCE THIS SYSTEM MOVES EASTWARD AS COOLER AIR AS EVIDENT BY THE -7 TO -10C H850 TEMPS ADVECT ACROSS THE REGION SUNDAY NIGHT INTO MONDAY. THE NORTHWEST FLOW WILL PERSIST ACROSS THE REGION...WITH A FEW SHORTWAVES TRACKING DOWN THE POLEWARD SIDE OF THE JET. THESE WILL INDUCE LOW LEVEL CIRCULATIONS...THE NEXT OF WHICH IS EXPECTED TO TRACK SOUTHWEST OF THE CWA ALONG THE MISSOURI RIVER VALLEY MONDAY NIGHT INTO TUESDAY. COLD AIR WILL AGAIN BE REINFORCED BEHIND THIS SYSTEM...WILL NO WARM UP POTENTIAL IN SIGHT UNTIL PERHAPS THE END OF THE WEEK AS ANOTHER WAVE MOVES ACROSS THE REGION. DEPENDING ON THE TRACK OF THIS SYSTEM...THE UPPER MIDWEST COULD SEE ONE DAY OF WARMER TEMPERATURES...BUT THE GUIDANCE IS CONSISTENT THAT THIS WILL BE SHORT LIVED AS ANOTHER ARCTIC AIRMASS WILL FOLLOW BEHIND THIS PASSING WAVE. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 1141 PM CDT SAT OCT 19 2013 A COMPLEX TAF PERIOD IS AHEAD AS A CLIPPER SYSTEM DIVES SOUTHEAST ACROSS SOUTHERN MINNESOTA SUNDAY. PRECIPITATION WILL BEGIN TO PUSH INTO WESTERN MN LATE TONIGHT AND SPREAD EAST INTO WISCONSIN LATE SUNDAY MORNING. THERMAL PROFILES INDICATE SNOW FOR MUCH OF CENTRAL MN...WITH A BIT OF SNOW POSSIBLE AT THE ONSET ACROSS EASTERN MN AND WESTERN WI. THINK TEMPERATURES ARE OVERDONE ON MOS...WHICH LEADS TO LOWER RH NEAR THE SURFACE AND THUS HIGHER CIGS. WENT MUCH MORE PESSIMISTIC WITH THE CIGS NORTH OF THE LOW TRACK AS INDICATED BY FORECAST SOUNDINGS AND HOPWRF MODEL. KMSP...ONSET OF PRECIP CONTINUES TO LOOK LIKE 13 OR 14Z WITH SNOW POSSIBLY MIXED WITH THE RAIN FOR A BRIEF TIME. BIGGEST UNCERTAINTY WILL BE CIGS SUNDAY. THE WARM FRONT WILL BISECT THE METRO AND MSP WILL BE SOMEWHERE BETWEEN THE IFR CIGS TO THE NORTH AND VFR OR MVFR CIGS TO THE SOUTH IN THE WARMER AIR. A SLIGHT NORTHWARD SHIFT OF THE FORECAST TRACK HAS LED TO A CONTINUATION OF MVFR CIGS. /OUTLOOK FOR KMSP/ MON...VFR WITH -RA/SN POSSIBLE. WINDS NW AT 15G25KT. TUE...VFR WITH MVFR CIGS POSSIBLE EARLY. WINDS NW AT 5-10 KTS. WED...MVFR CIGS POSSIBLE. WINDS W AT 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...JRB LONG TERM...JRB AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
729 PM EDT MON OCT 21 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE AREA EARLY TUESDAY MORNING. BEHIND THE FRONT EXPECT MUCH COLDER AIR WILL SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK. CLOUDY AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT RAIN MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW YORK. && .NEAR TERM /THROUGH TUESDAY/... 715 PM UPDATE... NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS SRN ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO. PCPN IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES NMM INDICATES THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT 06Z AND MAY NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT UNTIL NEXT UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY TEMPS RIGHT ON TARGET AT THIS TIME. PREV DISCUSSION BLO... BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY. FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE 40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY. MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... 00Z UPDATE... VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY EVENING AHEAD OF AN APPROACHING COLD FRONT FROM THE WEST. WINDS WILL WEAKEN QUICKLY AFTER SUNSET AS WE LOSE MIXING FROM THE SUN AND REMAIN UNDER 12 KNOTS. THE COLD FRONT WILL MOVE FROM W TO E EARLY TUESDAY MORNING FORCING THE WINDS TO TRANSITION FROM A SOUTHERLY FLOW TO A WEST/NORTHWESTERLY FLOW. LIGHT RAIN SHOWERS WILL ACCOMPANY THIS FRONT AND CAUSE RESTRICTIONS OF MVFR CIGS AND VISBYS AT KRME... KSYR... AND KITH THROUGH 15Z TUESDAY MORNING. THE REMAINING TAFS SITES ARE EXPECTED TO REMAIN VFR AS THE FRONT PASSES WITH LIGHT RAIN SHOWERS. WINDS TUESDAY AFTERNOON WILL PICK UP CAUSING LINGERING MVFR CIGS TO LIFT TO VFR. OUTLOOK... TUE NGT...VFR. WED/THU/FRI/SAT...MVFR AND OCNL IFR IN -SHRA/-SHSN....MAINLY ACRS CNTRL NY AFFECTING RME/SYR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...JAB NEAR TERM...JAB/PVN SHORT TERM...JAB LONG TERM... AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
718 PM EDT MON OCT 21 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE AREA EARLY TUESDAY MORNING. BEHIND THE FRONT EXPECT MUCH COLDER AIR WILL SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK. CLOUDY AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT RAIN MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW YORK. && .NEAR TERM /THROUGH TUESDAY/... 715 PM UPDATE... NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS SRN ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO. PCPN IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES NMM INDICATES THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT 06Z AND MAY NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT UNTIL NEXT UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY TEMPS RIGHT ON TARGET AT THIS TIME. PREV DISCUSSION BLO... BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY. FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE 40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY. MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5. && .AVIATION /23Z MONDAY THROUGH SATURDAY/... CDFNT OVER THE ERN GTLAKES WILL PASS THRU THE BGM CWA VERY LATE TNGT/EARLY TUE MRNG. VFR CONDITIONS WILL PREVAIL TIL AFTER MDNGT. XPCT A NARROW BAND OF -SHRA AND ASSCD MVFR CIGS TO ACCOMPANY THE FNT...AFFECTING CNTRL NY SITES IN THE 09-13Z TIME FRAME. AT AVP...IT APPEARS THAT CONDITIONS WILL REMAIN VFR EVEN WITH FROPA. LATER TMRW MRNG...SCT-BKN CIGS SHUD RISE INTO THE VFR CATEGORY. GUSTY S TO SW WINDS THIS AFTN 15-25 KTS...BECMG SRLY TNGT 5-15 KTS...THEN WRLY POST FROPA 10-20 KTS. OUTLOOK... TUE NGT...VFR. WED/THU/FRI/SAT...MVFR AND OCNL IFR IN -SHRA/-SHSN....MAINLY ACRS CNTRL NY AFFECTING RME/SYR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...JAB NEAR TERM...JAB/PVN SHORT TERM...JAB LONG TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
316 PM CDT SUN OCT 20 2013 .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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 117 PM CDT SUN OCT 20 2013 THE GENERAL TREND WILL BE IMPROVING CONDITIONS THROUGH THE PERIOD. FOLLOWED THE 15Z RAP FOR GUIDANCE ON TIMING THE IMPROVEMENT. SITES ALONG AND WEST OF THE VALLEY EXPECTED TO EVENTUALLY BE VFR BY LATER THIS EVENING...WHILE SITES EAST OF THE VALLEY WILL LIKELY REMAIN MVFR. GUSTY NORTHERLY WINDS THIS AFTERNOON WILL SUBSIDE A BIT TONIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SHORT TERM...ROGERS LONG TERM...ROGERS/TG AVIATION...TG
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
117 PM CDT SUN OCT 20 2013 .UPDATE... ISSUED AT 117 PM CDT SUN OCT 20 2013 WILL ALLOW THE REMAINING COUNTIES IN THE WINTER WEATHER ADVISORY TO EXPIRE AT 1 PM CDT. PERIODS OF LIGHT RAIN OR SNOW ARE POSSIBLE THIS AFTERNOON MAINLY ACROSS SOUTHEAST ND INTO WEST CENTRAL MN... BUT NOT EXPECTING MUCH IF ANY ADDITIONAL SNOW ACCUMULATION. VISIBILITIES HAVE RISEN ABOVE A MILE AND SURFACE TEMPERATURES NOW IN THE MID TO UPPER 30S ARE HELPING PRECIPITATION CHANGE BACK TO RAIN. SOME SLICK SPOTS ON AREA ROADWAYS STILL POSSIBLE...SO MOTORISTS SHOULD DRIVE WITH CAUTION. CLOUDS ARE STARTING TO BREAK ACROSS THE DEVILS LAKE BASIN AND PORTIONS OF THE FAR NORTHERN VALLEY...BUT WITH LOW CONVECTIVE TEMPERATURES AND CYCLONIC FLOW ALOFT...THINK THERE SHOULD BE A FAIR AMOUNT OF CU TO FILL BACK-IN. NORTHERLY WINDS NOW INCREASING TO NEAR 20 KTS ALONG AND WEST OF THE RED RIVER VALLEY AND THIS IS HANDLED WELL IN CURRENT GRIDS. REST OF THE FORECAST IN GOOD SHAPE WITH NO CHANGES AT THIS TIME. UPDATE ISSUED AT 1023 AM CDT SUN OCT 20 2013 MAIN QUESTION THIS MORNING IS WHAT TO DO WITH ONGOING WINTER WEATHER ADVISORY. AREA WEBCAMS SHOW WET ROADWAYS WITH LITTLE TO NO SNOW ACCUMULATION. THE MAJORITY OF MORNING SNOW REPORTS HAVE BEEN A HALF INCH OR LESS ON GRASSY SURFACES AND DO NOT ANTICIPATE MUCH MORE ACCUMULATION WITH CURRENT VISIBILITIES ABOVE ONE MILE. THE EXCEPTION BEING IN THE PARK RAPIDS/WADENA/DETROIT LAKES AREA WHERE SOME ACCUMULATION ON ROADWAYS IS VISIBLE ON MNDOT WEBCAMS. RAP/HRRR/LOCAL WRF SUGGEST THESE AREAS STAND THE BEST CHANCE OF ADDITIONAL SNOW THROUGH THE MORNING AS THE SURFACE LOW RAPIDLY MOVES INTO SOUTH-CENTRAL MN. ANOTHER 1-2 INCHES IS NOT OUT OF THE QUESTION. ALL THIS SAID...WILL CANCEL THE ADVISORY ACROSS ALL OF EASTERN ND AND MOST OF NORTHWEST MN...LEAVING IT INTACT FOR AREAS SOUTH AND EAST OF A LINE FROM FERGUS FALLS TO MAHNOMEN TO JUST SOUTH OF BEMIDJI. ROADS MAY STILL BE SLICK...HOWEVER...WITH SURFACE TEMPERATURES AT OR JUST ABOVE FREEZING. ADJUSTED POPS TO FOLLOW THIS THINKING...BUT REST OF FORECAST IS IN GOOD SHAPE WITH NO MAJOR CHANGES AT THIS TIME. UPDATE ISSUED AT 635 AM CDT SUN OCT 20 2013 THE CHALLENGE FOR THIS UPDATE WILL BE WINTER WEATHER HEADLINES. THIS VERY CHALLENGING EVENT CONTINUES TO UNFOLD...WITH SNOW NOW OCCURRING AT THE OFFICE HERE AND SNOW TO THE NORTH OF US. IT IS STILL RAIN IN THE FARGO AREA...BUT OBS JUST EAST OF FARGO INTO THE PKD/BJI/FSE AREA ARE ALL SNOW. OVER THE NEXT FEW HOURS...COLDER AIR SHOULD CHANGE RAIN TO SNOW IN THE FARGO AREA. WE HAVE HAD A REPORT OF AROUND AN INCH IN NE ND...WITH TEMPS AROUND FREEZING. NOT EXPECTING TOO MUCH SNOW ACCUMULATION FOR MOST OF ND COUNTIES WITH WARM GROUND TEMPS AND FAIRLY WEAK SNOW RATES...BUT AN INCH OF SNOW AND SOME ICY ROADS POSSIBLE THIS MORNING. EXPECT THE 1-2 INCH AMOUNTS IN THE HIGHER TERRAIN AWAY FROM THE VALLEY FLOOR IN ND AND MN. THERE SHOULD BE A BETTER CHANCE AT A FEW INCHES OF SNOW FROM MAHNOMEN TO PKD...AND THE ADVY LOOKS GOOD HERE. CAN/T EVEN RULE OUT AN INCH OR SO FROM FSE EAST TO BJI...BUT FOR NOW WON/T EXPAND ADVISORY BUT MONITOR. THEREFORE...FOR NOW WON/T ADJUST THE ADVISORY AND WE WILL CONTINUE TO MONITOR THROUGH THE MORNING FOR ANY NEEDED CHANGES. && .SHORT TERM...(TODAY THROUGH MONDAY) ISSUED AT 345 AM CDT SUN OCT 20 2013 THE MAIN CHALLENGE THIS MORNING WILL BE CURRENT HEADLINES AND PRECIP FOR THE REST OF TONIGHT AND SUNDAY. MODELS HAVE COME INTO BETTER AGREEMENT WITH THE OVERALL TRACK OF THE QPF BAND...BUT STILL SOME DIFFERENCES IN THERMAL FIELDS EVEN WITH MESOSCALE MODELS. THEREFORE...STILL SOME QUESTIONS AS TO WHO ACTUALLY GETS SOME ACCUMULATION. FOR THE NEAR TERM...GETTING JUST PLAIN RAIN AT THE OFFICE AND THIS WILL LIMIT ANY SNOW ACCUMS AT LEAST INITIALLY. THERE IS SOME MINOR ACCUMS LIKELY NEAR LANGDON SINCE THEY HAVE BEEN 32 FOR THE PAST FEW HOURS AND VSBYS BELOW 3SM. ALSO...WHEN LOOKING AT DUAL POL DATA...IT SEEMS THE CHANGEOVER TO SNOW AROUND AND NORTH OF GFK SHOULD OCCUR BY 9Z. WE WILL MONITOR CLOSELY THROUGH THE MORNING HOURS...AND MAY NEED TO CANCEL PORTIONS OF THE ADVISORY IF SNOW ACCUMS DO NOT OCCUR. TEMPS WILL STILL FALL BELOW FREEZING THROUGH THE PRE DAWN HOURS IN THE NORTHERN VALLEY...AND SOME SLICK SPOTS ON ROADS ARE POSSIBLE. EARLY THIS MORNING AND TODAY...EXPECT MOST OF THE PRECIPITATION TO HAVE CHANGED OVER TO SNOW BY 12Z...EXCEPT PERHAPS IN THE FAR SOUTH WHERE MAINLY RAIN SHOULD FALL. THERE SHOULD BE A TIME WHERE SOME SNOW ACCUMULATES MAINLY NORTH OF A DEVILS LAKE TO FARGO TO PARK RAPIDS LINE FROM AROUND 10Z-15Z. THERE COULD BE A FEW REPORTS OF AN INCH...PERHAPS 2...BUT WITH WARM BOUNDARY LAYER TEMPS LIMITING SNOW FALL INITIALLY...ACCUMS SHOULD BE LIGHT. WE WILL CONTINUE TO MONITOR ANY EXPECTED CHANGES IN THIS THINKING...SINCE ELEVATION WILL PLAY A ROLE IN SNOW ACCUMS AS THE BAND PROGRESSES INTO MN EARLY THIS MORNING. THERE IS ALSO AN AREA IN EASTERN POLK COUNTY INTO SOUTHERN CLEARWATER/BELTRAMI COUNTIES WHERE TEMPS ARE BELOW FREEZING. IF RAIN OCCURS HERE INITIALLY...COULD BE SOME ICING...ALTHOUGH LOOKING AT RWIS SITES SHOWS ROAD SFC TEMPS ARE IN THE MID 30S...SO FOR NOW WON/T EXTEND ADVISORY EAST BUT WILL MONITOR. NORTHERLY WINDS WILL INCREASE BEHIND THE FRONT AND GUST OVER 30 MPH IN THE VALLEY...AND IT WILL BE A BLUSTERY DAY. AFTER 18Z...EXPECT MORE OF A RAIN/SNOW MIX IN THE EAST AND ANY POTENTIAL FOR ACCUMS SHOULD END. FOR TONIGHT AND MONDAY...EXPECT THE POTENTIAL FOR SOME WRAPAROUND LIGHT SNOWS MAINLY IN THE EAST. TEMPS WILL CONTINUE TO BE VERY COLD...WITH WINDS FAIRLY STRONG TONIGHT AND MONDAY. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 345 AM CDT SUN OCT 20 2013 FOR MONDAY NIGHT THROUGH TUE NIGHT...IT SHOULD BE MAINLY DRY WITH PERHAPS A FEW LIGHT SNOW SHOWERS IN THE FAR NORTHEAST MON NIGHT. IT WILL REMAIN COLD WITH TEMPS WELL BELOW NORMAL. FOR WEDNESDAY-SATURDAY...LITTLE CHANGE IN THE LONGWAVE PATTERN IS ANTICIPATED THROUGH NEXT WEEKEND. WITH STRONG POSITIVE 500 MB HEIGHT ANOMALIES INTO THE NORTHEAST PACIFIC AND TROUGHING INTO THE EASTERN CONUS...THE NORTHERN PLAINS WILL REMAIN UNDER CHILLY NORTHWEST FLOW ALOFT. SHORTWAVE TROUGHS RIDING THE PERIPHERY OF THE WESTERN CONUS RIDGE WILL DIVE SOUTHWARD...ALLOWING REINFORCING SURGES OF COOL AIR TO SPILL INTO THE REGION...WITH DAY-TO-DAY TEMP VARIATIONS DEPENDENT ON THE TIMING OF THESE WAVES. HOWEVER...TEMPS LOOK TO REMAIN PRIMARILY BELOW NORMAL. NO SIGNIFICANT PRECIPITATION IS EXPECTED...WITH ONLY LOW CHANCES FOR SOME LIGHT RAIN/SNOW ASSOCIATED WITH ANY PROGRESSIVE SHORTWAVE TROUGHS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 117 PM CDT SUN OCT 20 2013 THE GENERAL TREND WILL BE IMPROVING CONDITIONS THROUGH THE PERIOD. FOLLOWED THE 15Z RAP FOR GUIDANCE ON TIMING THE IMPROVEMENT. SITES ALONG AND WEST OF THE VALLEY EXPECTED TO EVENTUALLY BE VFR BY LATER THIS EVENING...WHILE SITES EAST OF THE VALLEY WILL LIKELY REMAIN MVFR. GUSTY NORTHERLY WINDS THIS AFTERNOON WILL SUBSIDE A BIT TONIGHT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...ROGERS SHORT TERM...DK LONG TERM...DK/MAKOWSKI AVIATION...TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
815 PM EDT MON OCT 21 2013 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION TONIGHT. LOW PRESSURE AT THE SURFACE WILL CROSS FROM THE UPPER MIDWEST EAST THROUGH THE OHIO VALLEY ON TUESDAY AND TUESDAY NIGHT AS IT FOLLOWS A STRONG UPPER LEVEL TROUGH. THE COLDEST AIR OF THE SEASON WILL BE FOUND BEHIND THESE SYSTEMS AS HIGH PRESSURE IN THE MIDWEST HELPS USHER IN NORTHERLY WINDS TO THE OHIO VALLEY THROUGH THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... COLD FRONT HAVE MOVED INTO THE NORTHWEST COUNTIES AND WILL PUSH EAST OF THE FORECAST AREA BY AROUND 06Z. A BAND OF SHOWERS IS OCCURRING IN THE WAKE OF THE FRONT BUT THUS FAR ONLY AFFECTING THE NORTHERN PART OF THE AREA. HOWEVER RECENT HRRR AND RAP RUNS SUGGEST THAT SHOWERS WILL DEVELOP FURTHER SOUTH LATE IN THE EVENING AND THEN PROGRESS EAST CLEARING THE REGION BY DAYBREAK. CLOUDS WILL DECREASE FROM NORTHWEST TO SOUTHEAST LATE AT NIGHT AND TEMPERATURES WILL BE ABLE TO DROP INTO THE 30S IN ALL BUT THE SOUTHEAST. IT WILL GET COLD ENOUGH FOR SOME FROST IN THE NORTHWEST PART OF THE AREA. BUT THERE IS SOME QUESTION WHETHER WINDS WILL GET LIGHT ENOUGH FOR THIS TO HAPPEN. SO HAVE STAYED WITH PATCHY WORDING. NO CHANGES TO THE FROST ADVISORY. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... COOLER AIR WILL HAVE A CHANCE TO WARM UP ON TUESDAY BUT THAT WILL BE THE END OF IT AS TUESDAY NIGHT WILL SEE A SURFACE LOW TRACK EAST THROUGH THE OHIO VALLEY UNDERNEATH A STRONG UPPER TROUGH. THE TWO WILL PROVIDE ENOUGH WIDESPREAD LIFT TO CREATE SHOWERS OVERNIGHT AND WITH THE COLD AIR BEING USHERED IN BEHIND THEM...THE SHOWERS COULD MIX WITH SNOW BEFORE ENDING EARLY WEDNESDAY. READINGS TUESDAY WILL STRUGGLE TO REACH MUCH PAST 50 DEGREES WHILE WEDNESDAY WILL BE ENTRENCHED IN THE 40S WITH A TYPICAL NW-SE GRADIENT FOUND WITH THE COOLEST AIR BEING USHERED IN ON NORTHWEST WINDS ALOFT AND WESTERLY SURFACE WINDS. A SECONDARY WAVE OF ENERGY IN THE UPPER MEAN TROUGH WILL CROSS ESE THROUGH THE REGION WEDNESDAY NIGHT AND COULD RESULT IN ADDITIONAL SHOWERS OF A MIXED VARIETY. REGARDLESS OF THE INCREASED POTENTIAL FOR SEEING SNOW IN THE NEXT FEW DAYS...THERE WILL NOT BE ANY ACCUMULATION TO WORRY ABOUT AS SURFACE TEMPERATURES WILL BE ABOVE FREEZING OUTSIDE OF THE EARLY MORNING/DAYBREAK HOURS. && .LONG TERM /THURSDAY THROUGH MONDAY/... PERIOD BEGINS WITH THE H5 TROF SET UP OVER THE ERN U.S. AND NW FLOW WORKING ACROSS THE GREAT LAKES. AS EXPECTED IN THE FAST FLOW THE EXTENDED MODELS ARE SLIGHTLY DIFFERENT WITH STRENGTH AND PLACEMENT. TRIED TO GO WITH A CONSENSUS FORECAST. SO WENT WITH SLIGHTLY HIGHER POPS ACROSS THE SRN COUNTIES AT THE BEGINNING OF THE PERIOD...WITH SLIGHTLY LOWER POPS TO THE N. THERE SHOULD BE SOME DAYTIME REDEVELOP ON THURSDAY AS COLD AIR ALOFT INCREASES THE INSTABILITY...BEFORE THE ENERGY WORKS E OF THE FA. DUE TO THE SUB FREEZING COLD AIR AT H8...SOME SNOW COULD MIX ON THURSDAY. SFC HIGH PRESSURE BUILDS UP THE OHIO VALLEY THURSDAY NIGHT INTO FRIDAY...BRINGING AN END TO THE COLD AIR PCPN AND SUNNIER SKIES. MODELS DROP A WEAK CDFNT DOWN THRU THE LAKES SATURDAY INTO SATURDAY NIGHT. MOISTURE LOOKS VERY LIMITED. CARRIED A 20 POP WITH THE FROPA IN OHIO IN CASE A STRAY SHOWER DEVELOPS. HIGH PRESSURE BUILDS BACK IN FOR SUNDAY AND MONDAY. AS FOR TEMPERATURES...THE MUCH BELOW NORMAL TEMPERATURES WILL LINGER INTO THURSDAY WITH HIGHS IN THE MID TO UPPER 40S...BUT ARE EXPECTED TO WORK INTO THE 50S FOR THE WEEKEND. SUB FREEZING TEMPERATURES ARE POSSIBLE THURSDAY AND FRIDAY NIGHTS. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... COLD FRONT WILL MOVE THROUGH ALL OF THE TERMINALS EARLY IN THE TAF PERIOD. SHOWERS CAN BE EXPECTED FOR A FEW HOURS AFTER FRONTAL PASSAGE EXCEPT FOR PERHAPS IN THE CINCINNATI AREA. SHOWERS WILL BE LIGHT AND SHOULD NOT AFFECT VISIBILITY BUT THERE COULD BE A BRIEF PERIOD OF MVFR CEILINGS. CLOUDS WILL CLEAR BEFORE 12Z AND CONDITIONS WILL REMAIN VFR. SOME HIGH AND MID CLOUDS WILL MOVE BACK IN LATE. HIGH PRESSURE QUICKLY MOVING ACROSS THE REGION WILL ALLOW WINDS TO BACK DURING THE DAY. OUTLOOK...MVFR CEILINGS AND VISIBILITIES POSSIBLE TUESDAY NIGHT AND WEDNESDAY. WINDS GUSTING UP TO 30 KT WILL BE POSSIBLE ON WEDNESDAY AS WELL. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...FROST ADVISORY FROM 4 AM TO 9 AM EDT TUESDAY FOR OHZ026-034- 035-042-043. KY...NONE. IN...FROST ADVISORY FROM 4 AM TO 9 AM EDT TUESDAY FOR INZ050-058. && $$ SYNOPSIS...FRANKS NEAR TERM... SHORT TERM...FRANKS LONG TERM...SITES AVIATION...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
204 AM EDT SUN OCT 20 2013 .SYNOPSIS... A COLD FRONT WILL PASS THROUGH THE REGION THIS EVENING FOLLOWED BY A VISIT FROM HIGH PRESSURE ON SUNDAY AND MONDAY. THE PATTERN WILL TURN NOTICEABLY COOLER AND UNSETTLED NEXT WEEK AS AN UPPER TROUGH ESTABLISHES ITSELF OVER THE EASTERN UNITED STATES. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... REGIONAL RADAR LOOP AT 02Z SHOWS A DWINDLING LINE OF SHOWERS ASSOC WITH COLD FRONT ENTERING THE SUSQ VALLEY. DESPITE A DECENT AMT OF MOISTURE POOLING AHEAD OF FRONT...UPPER LVL SHORTWAVE AND ASSOC LG SCALE FORCING IS LIFTING NORTH OF THE BORDER...SO LITTLE CHC OF MORE THAN AN ISOLD SHOWER AS FRONT PUSHES THRU THE EASTERN COUNTIES BTWN 02Z-04Z. LATEST RAP OUTPUT INDICATES CDFRONT WILL CLEAR THE EASTERNMOST COUNTIES /SCHUYLKILL AND LANCASTER/ BY MIDNIGHT. BEHIND FRONT...ONLY REMAINING PRECIP WILL BE IN THE FORM OF LAKE EFFECT RAIN SHOWERS COMING OFF OF LK ERIE. CURRENT RADAR TRENDS AND RAP/NAM OUTPUT SUGGEST SHOWERS ACROSS WARREN/MCKEAN COS WILL SHIFT NORTH OF THE BORDER AFTER 06Z...AS BLYR FLOW BACKS TO THE WSW. CLEARING SKIES ALREADY DEVELOPING EAST OF THE MTNS AT 02Z AND EXPECT THAT TREND TO CONTINUE OVERNIGHT...AS DRIER WEST FLOW OVERSPREADS CENTRAL PA. STRATOCU MAY LINGER FOR A WHILE ACROSS THE LAUREL HIGHLANDS...BUT EXPECT CLEARING EVEN THERE LATE TONIGHT. THE INITIALLY GUSTY WEST WINDS SHOULD SLACKEN LATE TONIGHT...AS HIGH PRES RIDGE BUILDS IN FROM THE OHIO VALLEY. BLEND OF LATEST LAMP AND RAP GUIDANCE SUGGEST TEMPS WILL BOTTOM OUT IN THE M30S ACROSS THE ALLEGHENY PLATEAU...TO THE L40S OVR THE SUSQ VALLEY. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... HIGH PRESSURE WILL PASS JUST SOUTH OF THE STATE ON SUNDAY...PROVIDING THE AREA WITH SEASONABLY COOL AND DRY WX. ALTHOUGH A WSW BLYR FLOW WILL KEEP LINGERING LAKE EFFECT ACTIVITY NORTH OF THE BORDER...COLD TEMPS ALOFT SHOULD YIELD A GOOD AMT OF DIURNAL STRATOCU ACROSS THE NW MTNS. WIND WILL INCREASE A BIT FROM A MORNING LULL...AS THE ATMOS MIXES. MDL SOUNDINGS SUPPORT AFTN GUSTS BTWN 20-25KTS ACROSS THE NW MTNS...AND BTWN 10-15KTS ACROSS THE LOWER SUSQ VALLEY. HIGH TEMPS UNDER THE RATHER HOMOGENEOUS 0C-M2C 8H TEMPS WILL BE ALMOST ENTIRELY DEPENDENT ON ELEVATION AND DOWNSLOPE WARMING. MAXES SHOULD BE CLOSE TO 50F IN THE NW MTNS AND NEAR 60F IN THE VALLEYS/LOWER ELEVS OF THE SUSQ VALLEY. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... CENTRAL PA WILL BE ON NORTHERN EDGE OF ERODING HIGH PRESSURE RIDGE SUN NIGHT INTO MON...WITH A WARM FRONT LIFTING THROUGH OHIO VALLEY AND SKIRTING W PA. THIS WILL KEEP WEATHER FAIR AND MILD...WITH HIGHS MONDAY SLIPPING INTO THE 60S /ABOUT 4-8F ABOVE NORMAL/. THINGS START TO GO DOWNHILL MONDAY NIGHT AS NEW ENERGY STARTS DIVING OUT OF SOUTHERN CANADA ON THE WAY TO CARVING OUT A LARGE SCALE PERSISTENT TROF OVER THE EASTERN U.S. A BUILDING RIDGE OVER THE WEST COAST WILL HELP DEEPEN AN ADVANCING LOW...WHICH WILL DELIVER A STEADY FEED OF INCREASINGLY MORE CHILLY AIR ACROSS THE UPPER MIDWEST NEXT WEEK. THIS COLD AIR WILL PROPAGATE INTO THE LOWER LAKES AND LOCAL AREA IN THE WAKE OF A COLD FRONTAL BOUNDARY PROGGED FOR TUESDAY...AND REINFORCED BY SECONDARY TROUGH ON WEDNESDAY /AS ANOTHER LOW FORMS ALONG THE BOUNDARY AND SLIDES ACROSS MID ATLANTIC STATES JUST TO OUR SOUTH BEFORE SLIDING OFF THE COAST OF NEW ENGLAND/. SOME DIFFERENCES CONTINUE IN MODEL SOLUTIONS STARTING AROUND WEDNESDAY WHEN THE ECMWF BRINGS A STRONG SHORTWAVE OUT OF THE OHIO VALLEY. THE OPERATIONAL GFS AND THE GEFS /PREVIOUSLY WITH A FLATTER TROUGH/ ARE COMING MORE IN LINE WITH THE EC...WHICH WILL INCREASE OUR POP CHANCES FOR WED WITH A STEADY LIGHT RAIN POSS. AFTER THAT...CYCLONIC FLOW WILL CONTINUE TO ALLOW INCREASINGLY COOLER AIR TO FILTER IN ON NW FLOW. PLENTY OF COLD ADVECTION STRATOCU AND LAKE/OROGRAPHIC SHOWERS LOOKING LIKELY IN THE HIGHER WESTERN TERRAIN MID/LATE WEEK...WITH DOWNSLOPE COMPONENT TO WINDS KEEPING PRECIP AT A MIN FOR THE SE. LOW LEVEL TEMPS GET COLD ENOUGH /850MB TEMPS DIP BELOW 0C/ THAT LIGHT SHOWERS COULD BE MIXED WITH WET SNOW DURING THE CHILLIEST PART OF THE DAY AND OVERNIGHT. HIGH PRESSURE BUILDS IN LOW LEVELS FOR THE WEEKEND...BRINGING QUITE CHILLY MORNING TEMPS. BUT AN OVERALL MORE SETTLED WEATHER PATTERN. REINFORCING SHOT OF COLDER AIR POSS EARLY NEXT WEEK. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... MOST OF THE SHOWERS OFF LAKE ERIE WILL BE NORTH OF OUR AREA... BUT CLOUDS WILL LINGER INTO LATE MORNING OR EARLY AFT...GIVEN THE STRONG FLOW OF COLD AIR OVER THE LAKE. THE AIRMASS IS COLD ENOUGH TO RESLULT IN RADAR RETURNS OF ALMOST 50 DBZ ALONG THE LAKE ERIE SHORELINE. ANYWAY...AS WINDS SHIFT MORE TO THE SW THIS AFTERNOON AND WEAKEN...CLOUDS WILL THIN OUT. CLOUDS INCREASE ACROSS THE AREA BY MONDAY MORNING...AS ANOTHER LOW PRESSURE SYSTEM LIFTS NE ACROSS THE LOWER LAKES REGION. SOME SHOWERS WILL BE POSSIBLE LATER MONDAY AFT INTO TUE...AS THE NEXT COLD FRONT MOVES ACROSS THE AREA. OUTLOOK... TUE...FROPA. MVFR/IFR POSS DUE TO SHOWERS/CLOUDS...ESP NW. WED...MVFR POSS IN SHRA...ESP NW. THURS...BREEZY...MVFR CLOUDS/SHRA N/W. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LA CORTE NEAR TERM...FITZGERALD SHORT TERM...DANGELO/FITZGERALD LONG TERM...RXR AVIATION...JUNG/MARTIN
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
813 PM CDT MON OCT 21 2013 .UPDATE... COLD FRONT SHOWING UP WELL ON RADAR IMAGERY THIS EVENING AND IS CURRENTLY MOVING THROUGH MEMPHIS AND HAS JUST ENTERED NORTHWEST STEWART COUNTY. POST FRONTAL SHOWERS CONTINUE SPREADING EASTWARD ACROSS WEST TENNESSEE AND WEST KENTUCKY...AND THIS ACTIVITY WILL MOVE INTO NORTHWEST ZONES OVER THE NEXT FEW HOURS. HAVE ADJUSTED GRIDS/ZONES BASED ON LATEST OBS AND TRENDS AND KEPT HIGHEST POPS OVER THE NORTH. RAINFALL AMOUNTS ARE STILL EXPECTED TO BE LIGHT AND GENERALLY LESS THAN A TENTH OF AN INCH. OTHERWISE...LATEST MAV/MET MOS CONTINUES TO SHOW A CHILLY WEEK AHEAD WITH LOWS BACK INTO THE 30S FOR MOST OF THE MID STATE FROM WEDNESDAY MORNING ON...WITH HIGHS ONLY IN THE 50S AND EVEN 40S ON THE PLATEAU. 18Z GUIDANCE ALSO CONTINUES TO SUGGEST A LIGHT FREEZE FOR MUCH OF THE CWA FRIDAY MORNING AND A POTENTIAL HARD FREEZE SATURDAY MORNING AS A COLD 1028MB SURFACE HIGH SETTLES DIRECTLY OVER THE REGION. SHAMBURGER && .PREV DISCUSSION... /ISSUED 634 PM CDT MON OCT 21 2013/ UPDATE...FOR 00Z AVIATION. AVIATION...00Z TAF DISCUSSION. ONE OF MULTIPLE COLD FRONTS THAT WILL PASS THROUGH TN THIS WEEK IS CREEPING UP ON US. THE FRONT IS WEAK...THE RAINS ARE LIGHT AND THE MOISTURE ISN`T VERY DEEP. THIS SHOULD HELP TO KEEP US VFR THROUGHOUT THIS FROPA. -RA SHOULD BE NEAR KCKV BY 06 AND KBNA BY 08Z...AND I QUESTION WHETHER OR NOT THE RAIN WILL EVEN OCCUR IN KCSV. WIND SHIFT SHOULD COME SHORTLY BEFORE THE RAINS...SO KEEP THAT IN MIND. RAINS SHOULD END FOR TERMINALS BY MID-MORNING AND RETURN TO JUST HIGH CLOUDS BY THE AFTERNOON. PREV DISCUSSION... /ISSUED 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. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
634 PM CDT MON OCT 21 2013 .UPDATE...FOR 00Z AVIATION. && .AVIATION...00Z TAF DISCUSSION. ONE OF MULTIPLE COLD FRONTS THAT WILL PASS THROUGH TN THIS WEEK IS CREEPING UP ON US. THE FRONT IS WEAK...THE RAINS ARE LIGHT AND THE MOISTURE ISN`T VERY DEEP. THIS SHOULD HELP TO KEEP US VFR THROUGHOUT THIS FROPA. -RA SHOULD BE NEAR KCKV BY 06 AND KBNA BY 08Z...AND I QUESTION WHETHER OR NOT THE RAIN WILL EVEN OCCUR IN KCSV. WIND SHIFT SHOULD COME SHORTLY BEFORE THE RAINS...SO KEEP THAT IN MIND. RAINS SHOULD END FOR TERMINALS BY MID-MORNING AND RETURN TO JUST HIGH CLOUDS BY THE AFTERNOON. && .PREV DISCUSSION... /ISSUED 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. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 27
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
940 PM CDT MON OCT 21 2013 .UPDATE... ISSUED AT 938 PM CDT MON OCT 21 2013 HAVE BEEN FOLLOWING THE TRENDS OF THE HRRR AND RAP ALL EVENING AND THE 22.00Z NAM HAS NOW COME IN AS WELL...ALL WITH THE SNOW STRIPE FURTHER SOUTH IN IA BY 1-2 COUNTIES. HAVE TRENDED THE FORECAST THAT WAY WITH REDUCED PRECIPITATION CHANCES...AND LESS SNOWFALL /NOW ABOUT 0.5 INCHES VERSUS 1 INCH/ IN FAR SOUTH. WITH CLEAR SKIES AND SOME LOW-LEVEL RIDGING AND LIGHT WIND...HAVE ALSO COOLED LOW TEMPERATURES ACROSS THE SOUTH TOO. FORECAST SHOULD BE UP TO THE WEB SITE AND IN PRODUCTS SHORTLY. UPDATE ISSUED AT 702 PM CDT MON OCT 21 2013 HAVE BEEN MONITORING CURRENT CONDITIONS ACROSS THE DAKOTAS AND INTO IOWA...AS WELL AS MODEL FORECASTS WITH THE SNOW SWATH COMING THROUGH IA/MN LATER TONIGHT. OVERALL OPINION IS THAT THIS WILL BE A PRETTY NARROW BAND OF INTENSE LIFT WITH THE HIGHEST PROBABILITY OF SNOW TO THE SOUTH OF THE FORECAST AREA. LATEST HRRR RUNS ARE SLOWING THE ONSET OF THE SNOW JUST SOUTH OF THE FORECAST AREA...BUT REALLY AGREE WELL WITH THE LATEST RUC RUNS AND 21.18Z NAM. THIS WILL BE A CLOSE ONE...WITH THE BAND AFFECTING WATERLOO AND DUBUQUE. 21.18Z NAM COBB DATA SUGGESTS ABOUT 5 INCHES OF SNOWFALL THERE...BUT THIS DOES NOT TAKE INTO ACCOUNT MELTING. 21.18Z GFS COBB MUCH MORE TAME WITH ABOUT AN INCH. SNOW RATES IN THE BAND WILL CAUSE ACCUMULATIONS AND SEEMS DMX/DVN WITH A 1-3 INCH BAND SEEMS RIGHT FROM SIOUX FALLS SD TO THE QUAD CITIES IA. OELWEIN TO NORTH DUBUQUE HAVE THE BEST CHANCE OF SEEING AN INCH IN THE LA CROSSE FORECAST AREA. FORECAST ACROSS THE SOUTH LOOKS GOOD AND HAVE NOT CHANGED IT AT THIS TIME. HAVE DECREASED CLOUDS FOR THE EVENING WITH CLEARING WORKING IN SOUTH OF I-94. WINDS WILL DROP OFF QUICKLY THIS EVENING AND THINKING THERE WILL BE ENOUGH TO HOLD TEMPS ABOVE DEWPOINTS BEFORE CLOUDS ARRIVE FROM THE WEST. BUT...FOG HAS CROSSED MY MIND WEST OF MISS RIVER WHERE SURFACE RIDGING IS BUILDING IN. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 307 PM CDT MON OCT 21 2013 THE MAIN FOCUS FOR TONIGHT INTO TOMORROW IS WITH THE CHANCES FOR AN ACCUMULATING SNOW ACROSS NORTHEAST IOWA. CURRENTLY...A CLOSED MID LEVEL LOW IS DRIFTING EAST ACROSS NORTHERN MINNESOTA WHILE A BROAD SURFACE LOW IS CENTERED OVER EASTERN ONTARIO. THE BROAD CYCLONIC FLOW EXTENDS ACROSS MUCH OF THE UPPER MISSISSIPPI RIVER VALLEY AND HAS LEAD TO AN EXTENSIVE STRATOCUMULUS FIELD THAT ALSO HAS PRODUCED SOME OCCASIONAL VERY LIGHT FLURRIES. THE MORE INTENSE SNOW SHOWERS HAVE BEEN FURTHER NORTH CLOSER TO THE CLOSED MID LEVEL LOW AND SURFACE INVERTED TROUGH NEAR LAKE SUPERIOR. GIVEN THE CELLULAR LOOK TO THE CLOUDS AND THAT WEAK SURFACE HIGH PRESSURE WILL BE MOVING IN...SOME CLEARING MAY TAKE PLACE FOR A PERIOD THIS EVENING BEFORE THE NEXT SYSTEM MOVES IN AND BRINGS HIGH LEVEL CLOUD COVER IN WITH IT. THIS NEXT SYSTEM IS CURRENTLY IN SOUTH CENTRAL CANADA AND WILL DIVE SOUTHEAST ACROSS THE DAKOTAS ON INTO IOWA TONIGHT INTO TOMORROW MORNING. A NARROW BAND OF PRECIPITATION WILL ACCOMPANY THIS LOW WITH THE BEST LOW LEVEL FRONTOGENESIS STAYING JUST SOUTHWEST OF THE FORECAST AREA IN CENTRAL/EASTERN IOWA. THE 21.12Z MODEL SUITE IS ALL IN GOOD AGREEMENT WITH THE TIMING/TRACK OF THIS SYSTEM WITH SOME LIGHT PRECIPITATION MAKING IT INTO NORTHEAST IOWA...MAINLY FROM CHARLES CITY TO OELWEIN. THERMAL PROFILES SHOW THAT THERE IS ICE PRESENT THROUGHOUT THE EVENT AND THAT IT WILL BE COLD ENOUGH TO BE ALL SNOW AS WELL. WITH THE BETTER FORCING TO THE SOUTH...ONLY EXPECT SOME VERY MINOR ACCUMULATIONS AT A HALF INCH OR LESS IN THAT CHARLES CITY TO OELWEIN CORRIDOR. THE MAIN PERIOD FOR THIS SNOW APPEARS TO BE BETWEEN ABOUT 3AM AND 9AM TUESDAY MORNING BEFORE THE SYSTEM TRACKS TO THE SOUTHEAST OF THE REGION. TEMPERATURES WILL TEMPORARILY IMPROVE FOR A BRIEF PERIOD TUESDAY AS 850MB TEMPERATURES GO FROM AROUND -8C AT PRESENT UP TO -4C BEFORE THE NEXT COLD SURGE DROPS THEM BACK DOWN TO AROUND -8C IN THE AFTERNOON. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 307 PM CDT MON OCT 21 2013 ANOTHER MID LEVEL SHORT WAVE TROUGH WILL DIVE SOUTH ALONG THE WESTERN PERIPHERY OF THE LONG WAVE TROUGH THAT IS STUCK ACROSS THE NORTHEASTERN US AND EASTERN CANADA ON WEDNESDAY. THIS WILL BRING ANOTHER SURFACE LOW WITH PRECIPITATION THROUGH CENTRAL IOWA WITH THE QUESTION BEING WHETHER ANY OF IT WILL GET INTO NORTHEAST IOWA. THE TREND APPEARS TO BE TAKING THIS ONE FURTHER TO THE SOUTH THAN THE LOW COMING THROUGH TONIGHT. THERE IS ENOUGH OF A POSSIBILITY THAT SOME OF THIS PRECIPITATION COULD GET INTO NORTHEAST IOWA...SO HAVE LEFT SOME SMALL CHANCES FOR A SNOW CHANGING TO RAIN MIX IN THERE. WITH THIS SYSTEM COMING THROUGH THE REGION MORE SO DURING THE DAY THAN OVERNIGHT...SURFACE TEMPERATURES WILL LIKELY WARM ENOUGH TO CAUSE THAT CHANGE OVER. THE REST OF THE WEEK LOOKS TO STAY ON THE COLD SIDE WITH 850MB TEMPERATURES IN THE -6C TO -8C RANGE UNTIL FRIDAY WHEN SOME LOW LEVEL WARM ADVECTION FINALLY KICKS IN AS THE UPPER TROUGH BREAKS DOWN AND SHIFTS EAST. THE WAA WILL BEGIN AS ANOTHER SHORT WAVE DIVES INTO THE GREAT LAKES FRIDAY/SATURDAY. THE 21.12Z GFS IS A TAD FASTER WITH THIS FEATURE THAN THE 21.12Z ECMWF AND BRINGS TEMPS BACK DOWN A BIT FASTER AS WELL. IF THE ECMWF PANS OUT...HIGHS ON SATURDAY COULD BE A LITTLE HIGHER IN THE 50S...PARTICULARLY IN NORTHEAST IOWA/SOUTHWEST WISCONSIN. THE LONG TERM GUIDANCE HAS THEN COME AROUND TO SHOW SOME BROAD TROUGHING DEVELOPING IN THE NORTHWESTERN US WHICH WILL LEAD TO AN ELONGATED SURFACE LOW FORMING ACROSS THE CENTRAL PLAINS SUNDAY NIGHT INTO MONDAY. THIS FEATURE WILL BE OUR NEXT SHOT FOR A WIDESPREAD RAIN EVENT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 700 PM CDT MON OCT 21 2013 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. A CLEAR PERIOD THIS EVENING WILL BE FOLLOWED BY INCREASING MID-LEVEL CLOUDS NORTH OF A WEATHER SYSTEM MOVING FAST OUT OF THE DAKOTAS TO IL. THIS WILL CAUSE AN IFR SNOW BAND FROM KFSD-KDVN LATE TONIGHT AND INTO TUESDAY MORNING. THE TAF SITES WILL ONLY SEE SOME VFR CLOUDINESS. SOME INSTABILITY DEVELOPS IN THE LOW-LEVELS LATE TUESDAY AFTERNOON WHICH SHOULD BE SEEN AS BKN-OVC VFR CLOUDS. THERE MAY BE SOME FLURRIES AROUND AS WELL INTO THE EVENING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
702 PM CDT MON OCT 21 2013 .UPDATE... ISSUED AT 702 PM CDT MON OCT 21 2013 HAVE BEEN MONITORING CURRENT CONDITIONS ACROSS THE DAKOTAS AND INTO IOWA...AS WELL AS MODEL FORECASTS WITH THE SNOW SWATH COMING THROUGH IA/MN LATER TONIGHT. OVERALL OPINION IS THAT THIS WILL BE A PRETTY NARROW BAND OF INTENSE LIFT WITH THE HIGHEST PROBABILITY OF SNOW TO THE SOUTH OF THE FORECAST AREA. LATEST HRRR RUNS ARE SLOWING THE ONSET OF THE SNOW JUST SOUTH OF THE FORECAST AREA...BUT REALLY AGREE WELL WITH THE LATEST RUC RUNS AND 21.18Z NAM. THIS WILL BE A CLOSE ONE...WITH THE BAND AFFECTING WATERLOO AND DUBUQUE. 21.18Z NAM COBB DATA SUGGESTS ABOUT 5 INCHES OF SNOWFALL THERE...BUT THIS DOES NOT TAKE INTO ACCOUNT MELTING. 21.18Z GFS COBB MUCH MORE TAME WITH ABOUT AN INCH. SNOW RATES IN THE BAND WILL CAUSE ACCUMULATIONS AND SEEMS DMX/DVN WITH A 1-3 INCH BAND SEEMS RIGHT FROM SIOUX FALLS SD TO THE QUAD CITIES IA. OELWEIN TO NORTH DUBUQUE HAVE THE BEST CHANCE OF SEEING AN INCH IN THE LA CROSSE FORECAST AREA. FORECAST ACROSS THE SOUTH LOOKS GOOD AND HAVE NOT CHANGED IT AT THIS TIME. HAVE DECREASED CLOUDS FOR THE EVENING WITH CLEARING WORKING IN SOUTH OF I-94. WINDS WILL DROP OFF QUICKLY THIS EVENING AND THINKING THERE WILL BE ENOUGH TO HOLD TEMPS ABOVE DEWPOINTS BEFORE CLOUDS ARRIVE FROM THE WEST. BUT...FOG HAS CROSSED MY MIND WEST OF MISS RIVER WHERE SURFACE RIDGING IS BUILDING IN. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 307 PM CDT MON OCT 21 2013 THE MAIN FOCUS FOR TONIGHT INTO TOMORROW IS WITH THE CHANCES FOR AN ACCUMULATING SNOW ACROSS NORTHEAST IOWA. CURRENTLY...A CLOSED MID LEVEL LOW IS DRIFTING EAST ACROSS NORTHERN MINNESOTA WHILE A BROAD SURFACE LOW IS CENTERED OVER EASTERN ONTARIO. THE BROAD CYCLONIC FLOW EXTENDS ACROSS MUCH OF THE UPPER MISSISSIPPI RIVER VALLEY AND HAS LEAD TO AN EXTENSIVE STRATOCUMULUS FIELD THAT ALSO HAS PRODUCED SOME OCCASIONAL VERY LIGHT FLURRIES. THE MORE INTENSE SNOW SHOWERS HAVE BEEN FURTHER NORTH CLOSER TO THE CLOSED MID LEVEL LOW AND SURFACE INVERTED TROUGH NEAR LAKE SUPERIOR. GIVEN THE CELLULAR LOOK TO THE CLOUDS AND THAT WEAK SURFACE HIGH PRESSURE WILL BE MOVING IN...SOME CLEARING MAY TAKE PLACE FOR A PERIOD THIS EVENING BEFORE THE NEXT SYSTEM MOVES IN AND BRINGS HIGH LEVEL CLOUD COVER IN WITH IT. THIS NEXT SYSTEM IS CURRENTLY IN SOUTH CENTRAL CANADA AND WILL DIVE SOUTHEAST ACROSS THE DAKOTAS ON INTO IOWA TONIGHT INTO TOMORROW MORNING. A NARROW BAND OF PRECIPITATION WILL ACCOMPANY THIS LOW WITH THE BEST LOW LEVEL FRONTOGENESIS STAYING JUST SOUTHWEST OF THE FORECAST AREA IN CENTRAL/EASTERN IOWA. THE 21.12Z MODEL SUITE IS ALL IN GOOD AGREEMENT WITH THE TIMING/TRACK OF THIS SYSTEM WITH SOME LIGHT PRECIPITATION MAKING IT INTO NORTHEAST IOWA...MAINLY FROM CHARLES CITY TO OELWEIN. THERMAL PROFILES SHOW THAT THERE IS ICE PRESENT THROUGHOUT THE EVENT AND THAT IT WILL BE COLD ENOUGH TO BE ALL SNOW AS WELL. WITH THE BETTER FORCING TO THE SOUTH...ONLY EXPECT SOME VERY MINOR ACCUMULATIONS AT A HALF INCH OR LESS IN THAT CHARLES CITY TO OELWEIN CORRIDOR. THE MAIN PERIOD FOR THIS SNOW APPEARS TO BE BETWEEN ABOUT 3AM AND 9AM TUESDAY MORNING BEFORE THE SYSTEM TRACKS TO THE SOUTHEAST OF THE REGION. TEMPERATURES WILL TEMPORARILY IMPROVE FOR A BRIEF PERIOD TUESDAY AS 850MB TEMPERATURES GO FROM AROUND -8C AT PRESENT UP TO -4C BEFORE THE NEXT COLD SURGE DROPS THEM BACK DOWN TO AROUND -8C IN THE AFTERNOON. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 307 PM CDT MON OCT 21 2013 ANOTHER MID LEVEL SHORT WAVE TROUGH WILL DIVE SOUTH ALONG THE WESTERN PERIPHERY OF THE LONG WAVE TROUGH THAT IS STUCK ACROSS THE NORTHEASTERN US AND EASTERN CANADA ON WEDNESDAY. THIS WILL BRING ANOTHER SURFACE LOW WITH PRECIPITATION THROUGH CENTRAL IOWA WITH THE QUESTION BEING WHETHER ANY OF IT WILL GET INTO NORTHEAST IOWA. THE TREND APPEARS TO BE TAKING THIS ONE FURTHER TO THE SOUTH THAN THE LOW COMING THROUGH TONIGHT. THERE IS ENOUGH OF A POSSIBILITY THAT SOME OF THIS PRECIPITATION COULD GET INTO NORTHEAST IOWA...SO HAVE LEFT SOME SMALL CHANCES FOR A SNOW CHANGING TO RAIN MIX IN THERE. WITH THIS SYSTEM COMING THROUGH THE REGION MORE SO DURING THE DAY THAN OVERNIGHT...SURFACE TEMPERATURES WILL LIKELY WARM ENOUGH TO CAUSE THAT CHANGE OVER. THE REST OF THE WEEK LOOKS TO STAY ON THE COLD SIDE WITH 850MB TEMPERATURES IN THE -6C TO -8C RANGE UNTIL FRIDAY WHEN SOME LOW LEVEL WARM ADVECTION FINALLY KICKS IN AS THE UPPER TROUGH BREAKS DOWN AND SHIFTS EAST. THE WAA WILL BEGIN AS ANOTHER SHORT WAVE DIVES INTO THE GREAT LAKES FRIDAY/SATURDAY. THE 21.12Z GFS IS A TAD FASTER WITH THIS FEATURE THAN THE 21.12Z ECMWF AND BRINGS TEMPS BACK DOWN A BIT FASTER AS WELL. IF THE ECMWF PANS OUT...HIGHS ON SATURDAY COULD BE A LITTLE HIGHER IN THE 50S...PARTICULARLY IN NORTHEAST IOWA/SOUTHWEST WISCONSIN. THE LONG TERM GUIDANCE HAS THEN COME AROUND TO SHOW SOME BROAD TROUGHING DEVELOPING IN THE NORTHWESTERN US WHICH WILL LEAD TO AN ELONGATED SURFACE LOW FORMING ACROSS THE CENTRAL PLAINS SUNDAY NIGHT INTO MONDAY. THIS FEATURE WILL BE OUR NEXT SHOT FOR A WIDESPREAD RAIN EVENT. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING) ISSUED AT 700 PM CDT MON OCT 21 2013 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. A CLEAR PERIOD THIS EVENING WILL BE FOLLOWED BY INCREASING MID-LEVEL CLOUDS NORTH OF A WEATHER SYSTEM MOVING FAST OUT OF THE DAKOTAS TO IL. THIS WILL CAUSE AN IFR SNOW BAND FROM KFSD-KDVN LATE TONIGHT AND INTO TUESDAY MORNING. THE TAF SITES WILL ONLY SEE SOME VFR CLOUDINESS. SOME INSTABILITY DEVELOPS IN THE LOW-LEVELS LATE TUESDAY AFTERNOON WHICH SHOULD BE SEEN AS BKN-OVC VFR CLOUDS. THERE MAY BE SOME FLURRIES AROUND AS WELL INTO THE EVENING. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
716 AM CDT SUN OCT 20 2013 .UPDATE... DENSE FOG HAS FORMED OVER A FEW OF THE NORTHERN COUNTIES AND IN SPOTTY LOCATIONS NEAR JANESVILLE AND ALONG THE WISCONSIN RIVER VALLEY. HRRR HAS FOG LIFTING AROUND 10 AM. GIVEN SUNRISE IS COMING AND MARGINAL LENGTH OF ABOUT 3 HOURS...DECIDED TO GO WITH SPECIAL WEATHER STATEMENT RATHER THAN ZERO LEAD TIME DENSE FOG ADVISORY. TEMPERATURES ARE RIGHT AROUND FREEZING SO SOME RIMING AND SLIPPERY SPOTS POSSIBLE. MEANWHILE FROST AND FROZEN DEW DID FORM AT THE BUZZER WITH THE FOG HELPING THINGS OUT. WILL LET FROST ADVISORY EXPIRE ON TIME. && .PREV DISCUSSION... /ISSUED 336 AM CDT SUN OCT 20 2013/ TODAY...FORECAST CONFIDENCE IS HIGH. STRONG UPSTREAM SHORTWAVE TROUGH DIGGING INTO LONG WAVE TROUGH POSITION TODAY. THIS ALLOWS FLOW TO TURN FROM NORTHWEST TO WESTERLY DURING THE DAY ALOFT. SURFACE LOW OF CLIPPER LIKE SYSTEM CURRENTLY EAST OF BIS ND EXPECTED TO MOVE FROM SOUTHEAST SOUTH DAKOTA TO SOUTHERN MINNESOTA THIS MORNING...THEN MOVE INTO CENTRAL WISCONSIN THIS AFTERNOON. DECENT BAROCLINIC ZONE WITH THIS FEATURE WITH STRONG WARM ADVECTION SPREADING ACROSS WISCONSIN DURING THE DAY. THE STRONGEST WARM ADVECTION AND DEEPEST MOISTURE IS SHOWN TO CLIP THE FAR NORTH DURING THE DAY...SO MUCH OF THE DAY MAY BE DRY IN THE SOUTH. THE LACK OF RAIN IN THE SOUTH AND STRONG WARM ADVECTION REGIME COULD RESULT IN TEMPERATURES WELL INTO THE 50S AND PERHAPS EVEN LOWER 60S ALONG THE ILLINOIS BORDER. STRONG MOISTURE TRANSPORT DEVELOPS JUST AHEAD OF SURFACE COLD FRONT IN THE LATE AFTERNOON...WITH MODELS SHOWING RAPID INCREASE IN MOISTURE IN THE SOUTHEAST. PRECIPITABLE WATERS RISE TO ABOUT 0.75" AND THE MODELS SHOW ADDITIONAL BANDS OF PRECIPITATION FORMING AT THE BUZZER BEFORE THE FRONT MOVES THROUGH IN THE EVENING. TIMING OF THIS WILL BE CRITICAL AS IT WILL RUN ITS COURSE BETWEEN ABOUT 21-03Z...MAKING POP FORECASTS SOMEWHAT TRICKY. TONIGHT...FORECAST CONFIDENCE IS HIGH. DEEP CLOSED LOW DIGS INTO NORTHERN MINNESOTA WITH -34C 500 MB COLD CORE. THIS RESULTS IN 70 METER HEIGHT FALLS CENTERED NEAR LAKE SUPERIOR. SURFACE LOW TURNS TO THE NORTHEAST AND DEEPENS AS IT MOVES ACROSS THE UP INTO EASTERN LAKE SUPERIOR. THIS USHERS IN SIGNIFICANT COLD ADVECTION...SUBSIDENCE...AND DEEP DRYING. LINGERING RAIN IN THE EVENING SHOULD QUICKLY MOVE EAST. MONDAY THROUGH TUESDAY NIGHT...FORECAST CONFIDENCE IS MEDIUM. SHORT TERM MODELS IN DECENT AGREEMENT WITH FEATURES DURING THIS PERIOD...THOUGH THEY DO SHOW SOME DIFFERENCES. DEEP LOW PRESSURE SHIFTS FROM EASTERN LAKE SUPERIOR INTO ONTARIO CANADA MONDAY...THEN BRINGS A SURFACE TROUGH SOUTHEAST THROUGH NORTHEAST WISCONSIN MONDAY NIGHT. DEEP 500MB LOW SHIFTS FROM NORTHERN/NORTHEAST MINNESOTA TO EASTERN LAKE SUPERIOR MONDAY...THEN TO THE EAST MONDAY NIGHT. GFS/ECMWF/CANADIAN BRING STRONG VORTICITY MAXIMUM EASTWARD BUT JUST NORTH OF THE AREA MONDAY...WITH SHEARED VORTICITY IN THE AREA MONDAY NIGHT. THE NAM BRINGS THESE FEATURES SOUTHEAST THROUGH THE AREA LATER MONDAY AND MONDAY NIGHT. SIDED MORE WITH GFS/ECMWF/CANADIAN MODELS DURING THIS TIME. AREA FORECAST SOUNDINGS SHOWING DIURNAL CUMULUS CLOUDS MONDAY...THEN CLEARING OUT SOMEWHAT MONDAY NIGHT. THERE MAY BE SOME MIDDLE TO HIGH CLOUDS MONDAY NIGHT...THOUGH CONFIDENCE IS LOW AT THIS TIME. TIGHT PRESSURE GRADIENT MONDAY WILL ALLOW FOR GUSTY WEST WINDS...WITH GRADIENT REMAINING FAIRLY TIGHT MONDAY NIGHT. COOL HIGHS IN THE 40S ARE EXPECTED MONDAY PER 925MB TEMPERATURE FIELDS AND COLD AIR ADVECTION REGIME. THEY SHOULD DROP LOW ENOUGH MONDAY NIGHT FOR UPPER 20S TO LOWER 30S ACROSS THE ENTIRE AREA...ALLOWING FOR A KILLING FREEZE ACROSS THE AREA. DAY SHIFT SHOULD CONSIDER A FREEZE WATCH FOR MONDAY NIGHT...AND WILL CONTINUE TO HIGHLIGHT IN HAZARDOUS WEATHER OUTLOOK. GFS HAS TRENDED A BIT SOUTHWARD WITH THE PASSING LOW PRESSURE SYSTEM TUESDAY INTO TUESDAY EVENING. 00Z ECMWF ALSO IS SHOWING A SIMILAR LOW TRACK...WITH QPF JUST CLIPPING THE SOUTHWEST COUNTIES TUESDAY. THEY BOTH BRING A SHORTWAVE TROUGH THROUGH THE AREA AT 00Z WEDNESDAY. THE NAM/CANADIAN MODELS KEEP THE LOW AND ASSOCIATED QPF TO THE SOUTHWEST OF THE AREA. ADDED LOW POPS IN THE FAR SOUTHWEST COUNTIES TUESDAY GIVEN THE GFS/ECMWF LOW TRACKS. KEPT THE DRY FORECAST GOING ELSEWHERE TUESDAY INTO TUESDAY NIGHT. KEPT ANY POPS WITH POSSIBLE LAKE EFFECT PRECIPITATION OVER THE NEARSHORE WATERS ONLY TUESDAY NIGHT...AS LOW LEVEL WINDS LOOK TO REMAIN PARALLEL TO SHORE AT BEST. COOL HIGHS IN THE 40S LINGER WITH DIURNAL CUMULUS TUESDAY...WITH ANOTHER COLD NIGHT/KILLING FREEZE TUESDAY NIGHT IN THE UPPER 20S TO LOWER 30S. WEDNESDAY THROUGH SATURDAY...FORECAST CONFIDENCE IS MEDIUM. ECMWF/GFS SHOWING SIMILAR GENERAL TRENDS DURING THIS PERIOD...WITH SOME DIFFERENCES IN SPECIFIC FEATURES. THEY SHOW A GENERAL NORTHWEST FLOW AT 500MB CONTINUING ACROSS THE REGION WEDNESDAY INTO FRIDAY...WITH SEVERAL SHEARED VORTICITY MAXIMA PASSING THROUGH. HIGH PRESSURE SYSTEMS SHIFT SOUTHEAST ACROSS THE NORTHERN AND CENTRAL PLAINS DURING THIS TIME...MAINTAINING THE COLD AIRMASS OVER THE REGION. GFS FORECAST SOUNDINGS SHOWING SOME DIURNAL CUMULUS DEVELOPMENT EACH DAY...WITH LIMITED MOISTURE. THUS...PERIOD SHOULD BE FAIRLY DRY. GFS THEN BRINGS LOW PRESSURE SOUTHEAST ACROSS THE REGION FRIDAY NIGHT AND SATURDAY...WITH A STRONG SHORTWAVE TROUGH PASSAGE. THE ECMWF KEEPS THE AREA DRY FRIDAY NIGHT...WITH THE SHORTWAVE TROUGH PASSING THROUGH THE REGION SATURDAY. THE SURFACE LOW TAKES A SIMILAR PATH TO THE GFS...BUT IS ABOUT 12 TO 18 HOURS SLOWER. BOTH SYSTEMS BRING QPF TO THE AREA. GIVEN SOME UNCERTAINTY HERE...USED CONSENSUS POPS AND TEMPERATURES FOR THIS PERIOD. AVIATION/12Z TAFS/... PATCHY FOG MAY IMPACT THE TAF SITES BRIEFLY THIS MORNING WITH LIGHT WINDS UNDER WEAK SURFACE HIGH. MUCH OF THE RAIN WILL STAY NORTH OF THE TAF SITES THIS AFTERNOON AND WILL BE DEVELOPING OVER SOUTHERN WISCONSIN AHEAD OF THE COLD FRONT LATE IN THE AFTERNOON AND EARLY IN THE EVENING. THERE IS SUFFICIENT LOW LEVEL DRY AIR TO KEEP CEILINGS IN VFR RANGE IF IT DOES RAIN. WINDS WILL INCREASE FROM THE SOUTH TODAY AND THEN TURN WESTERLY TONIGHT AND BECOME GUSTY IN THE WAKE OF THE COLD FRONT. MARINE... STRONG PRESSURE FALLS IN THE LATE AFTERNOON AND EVENING AHEAD OF THE SURFACE LOW WILL USHER IN GUSTY SOUTH TO SOUTHWEST WINDS THAT WILL RAPIDLY INCREASE LATE IN THE AFTERNOON. THE WINDS WILL TURN TO THE SOUTHWEST AND THEN WEST TONIGHT AND THEN NORTHWEST MONDAY AND TUESDAY. THE COLD FRONT WILL CROSS LAKE MICHIGAN LATER TONIGHT. IT WILL BE UNSTABLE AS THE COLD AIR POURS IN TONIGHT SO EXPECT GUSTY WINDS AND HIGH WAVES IN THE COASTAL WATERS REQUIRING THE ISSUANCE OF SMALL CRAFT ADVISORY FROM TONIGHT INTO TUESDAY MORNING. GALE FORCE WINDS ARE EXPECTED AND MUCH HIGHER WAVES TOWARD OPEN WATERS. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ046-047-051- 052-056>060-062>072. LM...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 10 AM CDT TUESDAY FOR LMZ643>646. && $$ TODAY/TONIGHT AND AVIATION/MARINE...CRAVEN MONDAY THROUGH SATURDAY...WOOD
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
138 AM EDT TUE OCT 22 2013 .PREV DISCUSSION... /ISSUED 1039 PM EDT MON OCT 21 2013/ UPDATE... ADJUSTED SLIGHT POPS ONCE AGAIN FARTHER NORTH THROUGH TONIGHT ACROSS MUCH OF CENTRAL GEORGIA BASED ON COMBINATION OF PROGGED WEAK VORT MAX LOCATION AND GENERAL CONSENSUS OF MODEL PRECIP...THOUGH A FEW OUTLIERS INDICATING POTENTIAL ACROSS NORTH GEORGIA AS WELL. NOT BUYING INTO THIS RIGHT NOW...THOUGH RECENT HISTORY IN A SIMILAR SYSTEM PROVED OTHERWISE. WILL CONTINUE TO UPDATE AS NECESSARY...THOUGH ANY RAIN TOTALS ARE EXPECTED TO BE LIGHT. LATEST NAM CONDENSATION PRESSURE DEFICITS ARE A BIT LOWER AND MORE EXPANSIVE THAN EARLIER SO HAVE EXPANDED SOUTHEASTERN FOG POTENTIAL. REST OF FORECAST LOOKS TO BE ON TRACK AND PREVIOUS DISCUSSION FOLLOWS... BAKER PREV DISCUSSION... /ISSUED 813 PM EDT MON OCT 21 2013/ PREV DISCUSSION... /ISSUED 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 REDEVELOPING 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... 06Z UPDATE... MAINLY VFR EARLY THIS MORNING...THOUGH EXPECT MVFR FOG TO DEVELOP AT AHN/MCN. ISOLATED -RA/-SHRA OUT THERE AS WELL BUT NOT ENOUGH TO INCLUDE IN ANY TAFS AT THIS POINT. CIGS DROP TO LOW VFR THROUGH THE MORNING HOURS BUT WITH FAIRLY RAPID IMPROVEMENT LATE THIS AFTERNOON AS THE FRONT PUSHES THROUGH. WINDS SW AND LIGHT TO BEGIN WITH...VEERING TO W AND REMAINING AROUND 5KT /SLIGHTLY HIGHER AT ATL/. //ATL CONFIDENCE...06Z UPDATE... MEDIUM ON POSSIBILITY OF -SHRA/-RA. HIGH ON ALL OTHER ELEMENTS. TDP && .PRELIMINARY POINT TEMPS/POPS... ATHENS 71 49 67 40 / 20 5 0 0 ATLANTA 71 49 63 40 / 20 5 0 0 BLAIRSVILLE 67 43 57 33 / 20 5 0 0 CARTERSVILLE 71 45 62 37 / 20 0 0 0 COLUMBUS 75 53 71 44 / 30 5 0 0 GAINESVILLE 70 48 62 38 / 20 5 0 0 MACON 74 48 72 42 / 30 5 0 0 ROME 71 44 62 37 / 20 0 0 0 PEACHTREE CITY 72 46 66 38 / 20 5 0 0 VIDALIA 75 55 75 44 / 40 20 0 0 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
357 AM CDT TUE OCT 22 2013 .SHORT TERM /TODAY/... ISSUED AT 341 AM CDT TUE OCT 22 2013 MAIN CONCERN TODAY WILL OBVIOUSLY BE EVOLUTION OF CURRENT SYSTEM PASSING THROUGH THE MO VALLEY. DAKOTAS SHORT WAVE/PV ANOMALY CONTINUES TO STRENGTHEN AS IT APPROACHES WRN IA. ASSOCIATED PRECIP IS CURRENTLY SOMEWHAT PATCHY...LIKELY DUE TO FAIRLY LOW STATIC STABILITIES...BUT IS EXPECTED TO ORGANIZE SOMEWHAT MORE LATER THIS MORNING. FORCING IS DEEP...DRIVEN KINEMATICALLY BY DPVA AND DIVERGENCE IS LEFT EXIT REGION OF SASKATCHEWAN INTO HIGH PLAINS JET SEGMENT. THERMODYNAMIC FORCING IS CENTERED INTO IA AND CURRENTLY NOT THAT STRONG HOWEVER BUT MODELS DO STRENGTHEN THE THETA-E ADVECTION AND FRONTOGENETICAL FORCING INTO THE MORNING. THIS COUPLED FORCING WILL RESULT IN INCREASED DENDRITIC GROWTH ZONE /DGZ/ UPWARD MOTION. MODEL DEPICTIONS OF THIS...LOOKING AT 290-300K ISENT LAYER...ARE SOMEWHAT PROBLEMATIC HOWEVER AND AFOREMENTIONED LOW STATIC STABILITIES HAVE RESULTED IN COMPACT MODEL BULLSEYES OF LIFT WHICH ARE DIFFICULT TO EASILY TRANSLATE INTO HIGHER SNOW RATIOS AND RESULTANT SENSIBLE WEATHER. AREAS OF HIGHER SNOW RATES MAY END UP BEING NEAR CONVECTIVE AND SOMEWHAT ISOLATED. TO LOWER CONFIDENCE EVEN FURTHER...LOWEST 500M TEMPS HOVER RIGHT AROUND CRITICAL RAIN/SNOW VALUES WHICH ARE CO-LOCATED WITH THE DGZ LIFT. THIS MAKES RAIN/SNOW LINE UNCERTAIN AND WHETHER THE DGZ OMEGA WILL BE REALIZED IN RAIN OR SNOW. TAKING A BLEND OF THE HIGHER RES RAP AND NAM WOULD SUGGEST THE BEST LOCATION FOR ACCUMULATING SNOWS WOULD BE SIMILAR TO PREVIOUS TRACK FROM NW IA SEWD TO NEAR WATERLOO AND MARSHALLTOWN. STILL HAVE ACCUMS OF AN INCH OR LESS...WITH A POCKET OF HIGHER AMOUNTS NEAR AN IOWA FALLS/MARSHALLTOWN/WATERLOO TRIANGLE WHERE SNOW MAY BRIEFLY INTENSIFY AROUND 12Z OR 15Z. CONFIDENCE IN SNOW AMOUNTS IS QUITE LOW HOWEVER DUE TO CONCERNS ABOVE AND MELTING ISSUES WITH ROAD SURFACE TEMPS STILL 35F OR HIGHER AND THE GROUND WARM AS WELL. .LONG TERM /TONIGHT THROUGH MONDAY/... ISSUED AT 341 AM CDT TUE OCT 22 2013 MAIN FORECAST CONCERN IS WITH WEAK SHORTWAVE TO BRING ADDITIONAL PRECIP CHANCES ON WEDNESDAY AND THEN CONTINUED COLD TEMPERATURES THROUGH THE END OF THE WORK WEEK AND INTO THE WEEKEND. TONIGHT THROUGH WEDNESDAY...THE 22.00Z MODELS RUNS IN DECENT AGREEMENT WITH BRINGING WEAK VORT MAX FURTHER SOUTH AND CAUSED FOR A SHIFT IN POPS SOUTHWEST LEAVING THE NORTHEAST PORTIONS OF THE FORECAST AREA DRY TOMORROW. THERE IS A SMALL WINDOW FOR SNOW POTENTIAL DURING THE MORNING...ROUGHLY BETWEEN 12-15Z WEDNESDAY WHEN THE COLUMN BECOMES SATURATED AND REMAINS BELOW FREEZING AND ENOUGH FORCING IN THE SNOW GROWTH ZONE TO GENERATE SNOW. THIS WILL BE MAINLY OVER WEST CENTRAL TO NORTHWEST IOWA. HOWEVER...LOW CONFIDENCE WITH MUCH...IF ANY SNOW ACCUMULATION AS SURFACE TEMPERATURES LOOK TO QUICKLY RISE ABOVE FREEZING AND FORCING QUICKLY MOVES SOUTH. AS A RESULT...DECREASED SNOW AMOUNTS TO LESS THAN HALF AN INCH. THETA-E ADVECTION AND ISENTROPIC LIFT WILL QUICKLY MOVES FROM NORTHWEST IOWA TO SOUTHEAST IOWA DURING THE DAY WEDNESDAY. NAM/GFS HAVE DECENT FRONTOGENETICAL FORCING BETWEEN 750-600MB BY 12Z IN NORTHWEST IOWA AND THEN TRANSITION THE FORCING INTO SOUTH-CENTRAL TO SOUTHEAST PORTIONS OF THE FORECAST AREA BY 18Z. WITH THE QUICKER MOVEMENT OF THE SYSTEM...DECREASED POPS OVER THE WEST AND NORTH PAST 21Z. THURSDAY THROUGH MONDAY....LARGE SURFACE HIGH BUILDS INTO THE REGION UNDERNEATH NORTHWEST FLOW ALOFT THROUGH SATURDAY BEFORE THE GFS/ECMWF BRING A DRY COLD FRONT ACROSS THE STATE SOMETIME SATURDAY. NEXT LONGWAVE TROUGH BEGINS TO DIG INTO THE WESTERN U.S. BY EARLY NEXT WEEK PLACING AN INVERTED SURFACE TROUGH OVER IOWA BY MONDAY. THIS WILL BE THE NEXT BEST CHANCE OF PRECIP TO THE FORECAST AREA. && .AVIATION...22/06Z ISSUED AT 1158 PM CDT MON OCT 21 2013 STORM SYSTEM STILL ON TRACK TO IMPACT THE AREA TONIGHT INTO TUESDAY MORNING. KFOD AND KALO STILL HAVE POTENTIAL FOR IFR TO MVFR CIGS AND VSBYS WITH SNOW. A PERIOD MVFR CIGS AND PRECIPITATION ARE EXPECTED AT THE OTHER LOCATIONS AS WELL. A SWITCH TO NORTHWEST WINDS AND RISING CIGS WILL ARRIVE BY THE AFTERNOON. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...SMALL LONG TERM...PODRAZIK AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS WICHITA KS
334 AM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 333 AM CDT TUE OCT 22 2013 TODAY: ADDED A FEW SPRINKLES THIS MORNING BASED ON RADAR/SURFACE OBSERVATIONS...WITH RUC SHOWING TRANSIENT LIFT MOISTURE TRACKING ACROSS EASTERN EDGE OF FORECAST AREA EARLY THIS MORNING. OTHERWISE IT IS A CHALLENGING TEMPERATURE FORECAST WITH A LOT RIDING ON WIND DIRECTION AND CLOUDS. RELATIVELY DRY AIRMASS AND POSSIBLE DOWNSLOPE FLOW COULD REALLY BOOST TEMPERATURES THIS AFTERNOON. GIVEN SLIGHT COOL BIAS YESTERDAY AND WHAT SHOULD BE FAIRLY GOOD BREAKS IN CLOUDS LATER...WILL HEDGE A COUPLE DEGREES WARMER TODAY AND HOPEFULLY MINIMIZE ERROR EITHER WAY. TONIGHT: RIDGE AXIS WILL SETTLE OVER AREA WITH A SHARP FALL IN TEMPERATURES EARLY. SOME RETURN FLOW/CLOUDS MAY DEVELOP AFTER MIDNIGHT ACROSS WESTERN SECTIONS. HOWEVER CONDITIONS APPEAR FAVORABLE FOR WIDESPREAD FROST OVER FLINT HILLS/SOUTHEAST KS WHERE WINDS WILL LIKELY REMAIN NEAR CALM ALL NIGHT. WILL HOIST HEADLINES FOR FROST ADVISORY IN MOST LIKELY AREAS AND LET DAY SHIFT ADJUST WESTWARD IF NEEDED. WED-THU: QUICK WARM-UP SHOULD COMMENCE ON WED WITH GOOD WARMING JUST AHEAD OF NEXT FRONT THAT TRAVERSE MOST OF THE AREA DURING THE DAY. TEMPERATURES WILL LIKELY FALL IN THE AFTERNOON ACROSS NORTHERN HALF OF THE AREA AND WILL HAVE NON DIURNAL TEMPERATURES IN GRIDS. TOUGH CALL ON TEMPERATURES WED NIGHT WITH WIND INITIALLY...BUT WITH RIDGING BUILDING INTO AREA...MAY SEE TEMPERATURES TUMBLE TOWARDS DAYBREAK...MOST LIKELY IN SOUTHEAST KS. COLD AIR ADVECTION CONTINUES ON THU WITH MAXES 10-15 DEGREE COOLER THAN WED. LACK OF MOISTURE SHOULD PRECLUDE ANY MENTION OF PRECIPITATION. -HOWERTON .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 333 AM CDT TUE OCT 22 2013 MEDIUM RANGE MODELS STILL IN FAIRLY GOOD AGREEMENT GIVEN THE TYPICAL ISSUES OF TIMING SHORTWAVES IN NORTHWEST FLOW. RETURN FLOW ON FRI...WITH COLD FRONT MOVING THROUGH ON SAT. RETURN FLOW DEVELOPS SUN NIGHT AND PERSISTS INTO MON. SOME DIFFERENCES IN TIMING OF FRONT...BUT SMALL CHANCES CERTAINLY JUSTIFIED ON MON ACROSS SE KS. GIVEN RETURN OF CLOUDS AND INFLUX OF MOISTURE...HAVE BUMPED UP LOWS FOR MON. DIURNAL RANGE MAY BE EVEN MORE LIMITED ON MON IN SE KS WHERE LOW CLOUDS AND PRECIPITATION COULD PERSIST MOST OF THE DAY. -HOWERTON && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1141 PM CDT MON OCT 21 2013 FAIRLY QUIET VFR CONDITIONS ANTICIPATED THE NEXT 24 HOURS...WITH GUSTY NORTHWEST WINDS TUESDAY THE PRIMARY CONCERN. LIGHT SOUTHWEST WINDS ANTICIPATED TONIGHT...INCREASING SOME TOWARD DAYBREAK AND GRADUALLY TURNING MORE WESTERLY. COLD FRONT WILL MOVE SOUTHEAST ACROSS THE REGION TUESDAY MORNING...WITH STRONG/GUSTY NORTHWEST WINDS IN ITS WAKE. FURTHERMORE...MID-LEVEL CLOUDS WILL BE ON THE INCREASE FROM THE NORTHWEST OVERNIGHT...WITH SLIGHT CHANCE FOR A FEW PASSING SPRINKLES FOR MAINLY RSL-SLN. DIURNAL CUMULUS AROUND 6000 FT AGL SHOULD PREVAIL ACROSS THE AREA BY TUESDAY AFTERNOON AS COOLER AIR ALOFT SETTLES SOUTH. ADK && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 68 39 71 38 / 10 0 0 0 HUTCHINSON 67 38 69 37 / 10 0 0 0 NEWTON 65 38 69 36 / 10 0 0 0 ELDORADO 66 35 69 36 / 10 0 0 0 WINFIELD-KWLD 68 37 73 38 / 10 0 0 0 RUSSELL 66 37 67 34 / 0 0 0 0 GREAT BEND 66 37 68 34 / 0 0 0 0 SALINA 66 36 69 36 / 10 0 0 0 MCPHERSON 66 37 69 36 / 10 0 0 0 COFFEYVILLE 68 36 69 38 / 10 0 0 0 CHANUTE 67 33 65 35 / 10 0 10 0 IOLA 65 32 65 35 / 10 0 10 0 PARSONS-KPPF 67 33 67 34 / 10 0 0 0 && .ICT WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY FROM 1 AM TO 9 AM CDT WEDNESDAY FOR KSZ052-053- 069>072-094>096-099-100. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
521 AM EDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT TUE OCT 22 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE INTO THE WRN CONUS AND A BROAD DOWNSTREAM TROUGH OVER THE CNTRL AND ERN CONUS. A MID LEVEL LOW JUST NORTH OF THE SAULT WAS LIFTING SLOWLY TO THE ENE. AT THE SFC...LOW PRES WAS LOCATED A THE SRN END OF JAMES BAY WITH A TROUGH EXTENDING TO THE SW THROUGH ERN LAKE SUPERIOR INTO ERN UPPER MI. AFTER A BRIEF PERIOD OF MODERATE TO HEAVY SNOW ASSOCIATED WITH LOW LEVEL CONV AHEAD OF THE TROUGH...WIND PARALLEL SNOW BANDS HAVE DEVELOPED BUT WITH LESS ORGANIZED CONVECTIVE ELEMENTS. SNOWFALL AMOUNTS WERE IN THE 1 TO 3 INCH RANGE OVER THE WEST DURING THE EVENING BUT HAVE ONLY AMOUNTED TO LESS THAN INCH OVER N CNTRL UPPER MI NEAR NEGAUNEE. WITH LOW LEVEL TEMPS NEAR FREEZING AND MILD AIR MOVING IN FROM THE RELATIVELY WARM LAKE SUPERIOR...WATER TEMPS IN THE UPPER 40S...WET BULB ZERO HEIGHTS HAVE REMAINED HIGH ENOUGH FOR THE SNOW TO CHANGE BACK TO MAINLY RAIN OVER THE KEWEENAW AND ALONG LAKE SUPERIOR TO THE EAST. TODAY...EXPECT THE LAKE ENHANCED SNOW BANDS TO CONTINUE AS CAA DROPS 850 MB TEMPS FROM AROUND -7C TO NEAR -9C. HOWEVER...WITH DRIER AIR MOVING INTO THE REGION AND LOWER INVERSION HEIGHTS IN THE PRESENCE OF SYNOPTIC SCALE SUBSIDENCE BEHIND THE DEPARTING MID LEVEL LOW...THE SNOW SHOWER INTENSITY/COVERAGE WILL DIMINISH THIS MORNING LEAVING JUST SCT LIGHT SNOW/RAIN SHOWERS BY AFTERNOON. TONIGHT...THE MODELS SUGGEST A WEAK SHORTWAVE TROUGH MAY SLIDE INTO THE AREA. WITH 850 MB TEMPS REMAINING NEAR -8C...AN INCREASE IN 850-700 MB MOISTURE...AND MORE FAVORABLE LOW LEVEL CONV AS LAND BREEZES DEVELOP...SNOW SHOWERS ARE EXPECTED TO INCREASE FOR LOCATIONS FAVORED TY NW TO WNW FLOW. HOWEVER...GIVEN THE MARGINAL INSTABILITY...ANY ACCUMULATIONS ARE EXPECTED TO REMAIN AT AN INCH OR LESS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 350 AM EDT TUE OCT 22 2013 THE UPPER GREAT LAKES WILL STILL BE UNDER THE WESTERN SIDE OF THE UPPER TROUGH AT THE START OF THE LONG TERM PERIOD...WHICH WILL REMAIN IN PLACE THROUGH THURSDAY NIGHT. AT THE SURFACE...A LOW WILL BE LOCATED TO THE EAST OF JAMES BAY AND HIGH PRESSURE WILL BE SLIDING SOUTHEAST THROUGH THE NORTHERN PLAINS THROUGH THURSDAY. THIS WILL ALLOW NORTHWEST FLOW TO BE PERSISTENT ON WEDNESDAY AND THURSDAY. 850MB TEMPS DURING THIS PERIOD LOOK TO BE HOVERING RIGHT AROUND -7 TO -8C AND WITH LAKE SUPERIOR TEMPS ON AVERAGE AROUND 8-9C...THERE IS PLENTY OF OVER LAKE INSTABILITY TO SUPPORT LAKE EFFECT SHOWERS. ON WEDNESDAY MORNING...EXPECT THE WINDS TO BE NW TO WNW...BEFORE A WEAK SURFACE TROUGH AND SHORTWAVE SWEEPS THROUGH WEDNESDAY EVENING AND SHIFTS THE DIRECTION TO A MORE NORTH-NORTHWESTERLY DIRECTION. WILL HAVE THE HIGHEST POPS EAST OF GRAND MARAIS OVER THE EAST AND ALONG ALL OF THE HIGHER TERRAIN OVER THE WEST FOR WEDNESDAY...THEN SHIFTING TO MORE TRADITIONAL NW-NNW FLOW LOCATIONS FOR WEDNESDAY NIGHT (EG ALGER COUNTY OVER THE EAST). WILL CONTINUE TO SHOW DEFINITE POPS FOR THE FAVORED EASTERN CWA LOCATIONS SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS IDEA FOR THE LAST COUPLE OF DAYS. WILL CONTINUE THE HIGH POPS FOR THURSDAY...ALTHOUGH TEMPS MAY WARM A DEGREE. EVEN WITH THE LIKELY/DEFINITE POPS FOR WEDNESDAY...DON/T EXPECT THE INTENSITY TO BE AS STRONG AS LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT WHEN A QUICK PERIOD OF DEEPER MOISTURE WITH THE SHORTWAVE AND SURFACE TROUGH MOVES THROUGH. DEEP CLOUD LAYER (10-12KFT) AND LAKE INDUCED CAPE VALUES OF 300-500 J/KG SUPPORT THE POTENTIAL FOR STRONGER LAKE EFFECT SNOW BANDS ON WEDNESDAY NIGHT. THIS COULD EVEN END UP PRODUCING MODERATE TO HEAVY SNOWFALL IN QUICK BURSTS...SIMILAR TO WHAT WAS SEEN IN PORTIONS OF WESTERN UPPER MICHIGAN THIS AFTERNOON/EVENING (JACOBSVILLE SAW 2.6IN IN 1HR). THE MAIN LIMITING FACTORS FOR THIS EVENT WILL BE THE LOWER SNOW RATIOS AND MID-UPPER 30S NEAR SURFACE TEMPERATURES. CONTINUE TO THINK SNOW RATIOS WILL BE ON THE LOW END FOR TRADITIONAL LAKE EFFECT EVENTS...SINCE THE CLOUD LAYER WILL BE AT OR BELOW THE DGZ. THUS...WITH MUCH OF THE FORCING BELOW...WOULD EXPECT RATIOS TO BE IN THE 10-13 TO 1 RANGE INSTEAD OF THE NORMAL 17-25 TO 1. IN ADDITION...WITH UPPER 40 DEGREE WATER MODIFYING THE NEAR SURFACE AIR...LOCATIONS NEAR LAKE SUPERIOR WILL BE HOVERING IN THE MID TO EVEN UPPER 30S. THIS WILL TRY TO PUSH WETBULB ZERO VALUES UP TO 1KFT...WHICH WOULD BE ENOUGH FOR SOME MIXING OF RAIN/SNOW NEAR THE SHORELINE. IN ADDITION...THOSE WARMER SURFACE TEMPERATURES WILL ATTEMPT TO LIMIT THE SNOWFALL ACCUMULATION EXCEPT UNDER THE STRONGER BANDS...WHERE THE RATE WILL COMPENSATE FOR THE WARMER TEMPS. THEREFORE...PINNING DOWN SNOWFALL AMOUNTS WITH THE MULTIPLE FACTORS IS TRICKY FOR THIS EARLY SEASON EVENT. IN GENERAL...THINK THE SNOWFALL AMOUNTS DURING THE WEDNESDAY AFTERNOON/NIGHT PERIOD WILL BE UNDER ADVISORY CRITERIA (GENERALLY 1-3INCH) WITH SOME LOCATIONS SEEING ADVISORY AMOUNTS (3-4INCH) WHERE ANY STRONGER BANDS SETS UP. ONE OTHER ITEM TO MENTION FOR THE WEDNESDAY AFTERNOON AND NIGHT PERIOD IS THE POTENTIAL FOR SOME WATERSPOUTS OVER THE SOUTHEASTERN PART OF LAKE SUPERIOR. WITH THE CONVECTIVE CLOUD DEPTH OF 10-12KFT AND DELTA-T VALUES AROUND 16...THAT DOES PLACE THAT AREA ON THE EDGE OF THE WATERSPOUT POTENTIAL ON THE SZILAGYI WATERSPOUT NOMOGRAM. THUS...WILL PUT IN A SLIGHT CHANCE MENTION IN THAT AREA AND THEN END IN BY THURSDAY MORNING SINCE THE MOISTURE DEPTH BEGINS TO LESSEN. THE UPPER TROUGH WILL FINALLY BEGIN SHIFTING EAST ON THURSDAY NIGHT AND A HIGH PRESSURE RIDGE WILL BEGIN TO MOVE EAST INTO THE UPPER GREAT LAKES. THIS WILL BRING DRIER AIR INTO THE CWA FROM WEST TO EAST WHILE BACKING THE WINDS TO THE SOUTHWEST. THUS...EXPECT THE ONGOING LAKE EFFECT PRECIPITATION TO DIMINISH OVER THE WEST AND THEN SLOWLY DIMINISH AND SHIFT EAST OVER THE EASTERN CWA. FORTUNATELY...THE MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH THE SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE WEST AND SLIDING SOUTHEAST INTO THE UPPER GREAT LAKES REGION ON FRIDAY NIGHT INTO SATURDAY. THIS CLIPPER SYSTEM (WITH THE LOW SLIDING ALONG THE EASTERN SHORE OF LAKE SUPERIOR) SHOULD PRODUCE SOME PRECIPITATION OVER THE CWA ON FRIDAY NIGHT AND HAVE THE HIGHEST POPS OVER THE NORTHEAST HALF. THEN AFTER THE COLD FRONT MOVES THROUGH...EXPECT THERE TO BE A PERIOD OF LAKE ENHANCED RAIN/SNOW IN THE NORTHWEST WIND FAVORED LOCATIONS AS 850MB TEMPS FALL BACK TO -6C. WILL HIGHLIGHT THE HIGHEST POPS IN THOSE LOCATIONS FOR SATURDAY AND THEN GRADUALLY DIMINISH THEM SATURDAY NIGHT INTO SUNDAY...AS THE UPPER TROUGH SHIFTS EAST AND HIGH PRESSURE MOVES OVER THE CWA. IT LOOKS LIKE THE SUNDAY INTO SUNDAY NIGHT PERIOD WILL GIVE A LITTLE BIT OF A REPRIVE TO THE UNSETTLED WEATHER THAT WE WILL SEE THIS WEEK. LATEST TRENDS IN THE 00Z MODEL RUNS HAVE THE UPPER TROUGH THAT WILL BE DIGGING OVER THE ROCKIES POTENTIALLY BECOMING CUTOFF OVER THE WEST COAST. AS THIS OCCURS ON MONDAY...AN ELONGATED TROUGH ASSOCIATED FROM A LOW IN THE CENTRAL PLAINS WILL SLOWLY MOVE EAST ACROSS THE AREA. THIS WILL BE SOMETHING TO KEEP AN EYE ON...AS TEMPERATURES WILL LIKELY BE COLD ENOUGH FOR SNOW ALOFT (ALTHOUGH SURFACE TEMPERATURES ARE MARGINAL) AND IT COULD PRODUCE MEASURABLE SNOW. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 123 AM EDT TUE OCT 22 2013 ALTHOUGH THERE MAY BE SOME IFR CONDITIONS AT IWD/CMX EARLY THIS MRNG WITH UPSLOPE GUSTY NW FLOW IN THE WAKE OF TROF PASSAGE...EXPECT MVFR WX TO DOMINATE MOST OF THIS FCST PERIOD WITH CHILLY NW FLOW BTWN DEPARTING LO PRES TROF AND INCOMING HI PRES RDG. CLOSER APRCH OF THE SFC RDG/WEAKER PRES GRADIENT LATER TODAY WL ALLOW GUSTY NW WINDS TO DIMINISH. AT SAW...VFR CONDITIONS EARLY WL GIVE WAY TO A PERIOD OF MVFR CIGS WITH ARRIVAL OF DEEPER MSTR ACCOMPANYING THE TROF...BUT VFR WX WL RETURN THIS AFTN WITH CLOSER APRCH OF RDG. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT TUE OCT 22 2013 NORTH TO NORTHWEST GALES THIS MORNING ARE EXPECTED TO DIMINISH BY AFTERNOON AS THE GRADIENT WEAKENS BEHIND A DEPARTING TROUGH. HOWEVER...WITH PERSISTENT LOW PRES TO THE EAST AND RIDGE OVER THE NORTHERN PLAINS...WINDS WILL BE LINGER IN THE 20 TO 30KT RANGE THROUGH THE THU. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ005. LAKE SUPERIOR... GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LSZ264>267. GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...KC MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
347 AM EDT TUE OCT 22 2013 .SHORT TERM... TODAY AND TONIGHT CONFLUENT FLOW ALOFT THROUGH THE SOUTH FLANK OF THE UPPER LOW WILL MAINTAIN THE MID LEVEL DRY SLOT OVER THE SOUTHERN GREAT LAKES FOR MOST OF TODAY. THIS WILL KEEP THE INFLUENCE OF LAKE MICHIGAN SUBDUED ON THIS SIDE OF THE STATE, ESPECIALLY IN TERMS OF PRECIPITATION AND POSSIBLY EVEN CAUSING A DISRUPTION IN THE CLOUD FIELD. TRENDS IN LOW LEVEL RH PROFILES IN THE NAM AND RAP MODELS INDICATE DRY AIR FROM THE MIDWEST AS LOW AS 850 MB DURING THE MORNING WHICH COULD LEAD TO SOME BREAKS IN THE LAKE CLOUD PATTERN OR A TENDENCY FOR THE CLOUDS TO HUG CLOSER TO THE SHORELINE OVER SW LOWER EARLY IN THE DAY. THE LATEST SATELLITE IMAGERY SUPPORTS A GENERAL PARTLY SUNNY START TO THE DAY AND ALLOWS FOR SOME RENEWED STRATOCU FORMATION DUE TO SURFACE HEATING AND BEFORE HIGH CLOUDS INCREASE WITH THE NEXT SHORT WAVE LATE IN THE DAY. THE BREAKS OF SUNSHINE WILL HELP MAX TEMPS RECOVER INTO THE MID AND UPPER 40S. THE NEXT SHORT WAVE WILL ARRIVE OVER INDIANA FROM THE CENTRAL PLAINS BY EVENING NEARLY IN PHASE WITH THE SECONDARY SURFACE TROUGH SLIDING THROUGH THE NORTHERN GREAT LAKES. THE SURFACE TROUGH WILL MOVE THROUGH SE MICHIGAN DURING THE LATE AFTERNOON AND EVENING WHILE THE SHORT WAVE APPROACHES THE SOUTHERN MICHIGAN BORDER. THE COMBINATION OF THESE TWO FEATURES WILL GIVE INSTABILITY OVER LAKE MICHIGAN A CHANCE TO PERK UP, ALONG WITH BOUNDARY LAYER INSTABILITY DUE TO SURFACE HEATING, FOR A CHANCE OF LIGHT RAIN SHOWERS DURING THE LATE AFTERNOON. THE BEST CHANCE OF RAIN WILL BE DURING THE EVENING GENERALLY SOUTH OF THE I-69 CORRIDOR WHERE THE NORTH FLANK OF THE SHORT WAVE FORCING WILL INTERACT WITH THE SURFACE TROUGH. THIS REFLECTS A SOUTHWARD MODEL ADJUSTMENT ON TRACK OF SHORT WAVE WITH THE MID LEVEL TROWAL AXIS REMAINING SOUTH OF THE STATE LINE. MODEL DEPICTIONS OF DCVA ARE TOO WEAK TO GO WITH ANYTHING GREATER THAN A CHANCE POP BEFORE THE SYSTEM EXITS EASTWARD AFTER MIDNIGHT. MOST OF THE OVERNIGHT HOURS WILL THEN BE DOMINATED BY RENEWED LOW LEVEL COLD ADVECTION ON NW FLOW. BOTH THICKNESS FIELDS AND MODEL SOUNDINGS INDICATE PRECIPITATION POTENTIAL ENDED BY THE TIME THE BOUNDARY LAYER COOLS ENOUGH FOR SNOW, AND AS NORTHWEST FLOW CONFINES LAKE EFFECT CLOSER TO LAKE MICHIGAN. MIN TEMPS NEAR THE FREEZING MARK LOOK ON TARGET BY SUNRISE WEDNESDAY. && .LONG TERM... LONGWAVE TROUGHING ANCHORED BY A LARGE CLOSED LOW OVER THE GREAT LAKES WILL MAINTAIN MOIST CYCLONIC FLOW OVER THE AREA UNTIL THE DEPARTURE OF THE LOW TO THE NORTHEAST LATE IN THE WEEK. IN THE MEANTIME, NORTHWEST GRADIENT FLOW AROUND THE EASTERN FLANK OF HIGH PRESSURE BUILDING INTO THE CENTRAL CONUS WILL KEEP DAYTIME HIGHS IN THE MID TO UPPER 40S BENEATH H85 TEMPS PROGGED TO HOVER AROUND -5C. IN GENERAL, NORTHWEST FLOW WILL MINIMIZE CONCERN FOR LAKE EFFECT SHOWERS TO ADVANCE INTO THE AREA AS CONVECTIVE PLUMES OFF OF LAKE MICHIGAN WILL TEND TO BE SHUNTED TO OUR SOUTHWEST. THE EXCEPTION WILL BE WEDNESDAY WHEN THE LOW LEVEL FLOW IS PROGGED TO BACK TOWARD WESTERLY AHEAD OF AN APPROACHING SHORTWAVE. WITH THE HELP OF DIURNAL HEATING, A DEEP CONVECTIVE BOUNDARY LAYER WITH ORIGINS OVER LAKE MICHIGAN STANDS A DECENT CHANCE OF ADVECTING EAST INTO THE AREA. CHANCE POPS THEREFORE REMAIN IN PLACE FOR WED AFTERNOON, WITH THE BEST CHANCE FOR SHOWERS SOUTH OF I-69. LOW-LEVEL FLOW WILL BACK TO A LESSER DEGREE ON WED NIGHT AS A SHEARED H5 PV ANOMALY TRACKS ACROSS THE MI/OH BORDER. DYNAMIC FORCING ASSOCIATED WITH THE WAVE ITSELF WARRANTS CHANCE POPS NEAR THE OHIO BORDER, BUT POTENTIAL WILL BE LIMITED WITH THE DEEPER MOISTURE CONFINED TO THE OHIO VALLEY. MOIST CYCLONIC FLOW IN ADDITION TO CONTRIBUTIONS FROM LAKE SUPERIOR/MICHIGAN WILL ENSURE A SUBSTANTIAL BOUNDARY LAYER CONTRIBUTION TO A MOSTLY CLOUDY SKY CONDITION THAT IS FORECAST TO PERSIST THROUGH AT LEAST THURSDAY NIGHT. INHERITED FORECAST LOWS NEAR 30 FOR MOST AREAS STILL LOOK REASONABLE, BUT ANY POTENTIAL FOR CLEARING WILL BE WORTH MONITORING AS A FEW HOURS OF GOOD RADIATING WITHIN THE RESIDENT AIRMASS WOULD SEND TEMPS WELL INTO THE 20S. SHORTWAVE RIDGING IN ADVANCE OF ANOTHER HIGH-LATITUDE WAVE WILL WORK INTO THE AREA ON FRIDAY AGAINST A BACKDROP OF LARGER SCALE HEIGHT RISES OWING TO EASTWARD PROGRESSION OF THE LONGWAVE TROUGH. HIGH PRESSURE WILL BUILD INTO THE AREA AS A RESULT AND SHOULD HELP BREAK UP BOUNDARY LAYER CLOUD COVER TO SOME EXTENT, BUT HIGHS WILL AGAIN REMAIN IN THE 40S WITH THE THERMAL TROUGH PROGGED TO MAINTAIN ITS GRIP ON THE AREA. && .MARINE... A SECONDARY SURGE OF COLD AIR SPREADING OVER THE GREAT LAKES TODAY WILL REQUIRE GALE WARNINGS TO CONTINUE OVER NORTHERN AND CENTRAL LAKE HURON. WARNINGS HAVE BEEN ADDED FOR SAGINAW BAY AS FREQUENT GUSTS TO 35 KNOTS ARE NOW EXPECTED THERE AS THE WIND FUNNELS DOWN THE CENTER OF THE BAY. SMALL CRAFT ADVISORIES WILL HOLD ALONG THE SOUTHERN LAKE HURON NEARSHORE AREAS. THE STRONG WIND WILL KEEP WATERSPOUT POTENTIAL LOW EVEN AS INSTABILITY INCREASES OVER THE WATER TODAY WITH A BETTER CHANCE OVER THE OPEN WATERS OF LAKE HURON TONIGHT AS THE WIND DIMINISHES. WIND SPEED WILL CONTINUE TO DIMINISH TUESDAY NIGHT INTO WEDNESDAY BUT WILL REMAIN FROM THE NORTHWEST AND WEST, MAINTAINING BELOW NORMAL TEMPERATURE THROUGH THE END OF THE WEEK. && .AVIATION...ISSUED 1152 PM EDT MON OCT 21 2013 //DISCUSSION... LAKE EFFECT STRATUS WILL BE THE PREDOMINANT CHALLENGE THIS FORECAST AS THE SEASON GETS OFF TO A BIT OF AN EARLY START AS COLD...WESTERLY FLOW BECOMES ESTABLISHED AROUND BASE OF EXPANSIVE UPPER TROUGH OVER THE AREA. THE LOW LEVEL FLOW WILL BE SOUTHWEST OVERNIGHT IN ADVANCE OF NEXT EMBEDDED SHORTWAVE TROUGH...WHICH WILL TEND TO FOCUS CIGS FROM PTK NORTH WITH SCT STRATUS MUCH OF THE TIME YIP/DTW/DET. WITH FLOW VEERING TO WEST AND THEN NORTHWEST TUESDAY INTO TUESDAY EVENING WITH THE PASSAGE OF THIS SURFACE TROUGH...MVFR/LOWER VFR CIGS WILL EXPAND BACK SOUTH TO COVER ALL TERMINALS. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILINGS AOB 5000 FEET AFTER 15Z TUESDAY WITH HIGHER CONFIDENCE AFTER 00Z. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ421-LHZ422...UNTIL 8 PM TUESDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...FROM 8 PM TUESDAY TO 8 AM WEDNESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT SANILAC...UNTIL 8 AM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BT LONG TERM....JVC MARINE.......BT AVIATION.....DG YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
319 AM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 315 AM CDT TUE OCT 22 2013 LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW THE UPPER LOW WHICH BROUGHT MUCH COLDER TEMPERATURES TO THE AREA BEING SHUNTED INTO EASTERN ONTARIO AS A FEW REINFORCING SHORTWAVES DROP SOUTHEAST THROUGH CENTRAL CANADA INTO THE HIGH PLAINS. THE MAIN SHORTWAVE OF INTEREST FOR THE SHORT TERM CAN BE SEEN OVER EASTERN SOUTH DAKOTA... AND IS HELPING TO GENERATE THE LIGHT PCPN SEEN ON RADAR AND SURFACE OBS OVER FAR SOUTHWEST MINNESOTA... EASTERN SOUTH DAKOTA... AND NORTHERN IOWA. MOST OF THIS ACTIVITY LOOKS LIKE IT WILL REMAIN SOUTH OF OUR AREA THIS MORNING... SO MAINLY JUST MENTIONED SOME FLURRIES OR LOW POPS WITH NO SNOWFALL ACCUMULATIONS. OTHERWISE... TODAY LOOKS BENIGN ACROSS THE FORECAST AREA... WITH SOME PEAKS OF SUN INTERSPERSED WITH LINGERING STRATOCU. WE MAINTAIN SOMEWHAT OF A 925-850MB THERMAL TROUGH OVER THE AREA TODAY... WHICH SHOULD KEEP PLENTY OF CLOUDS IN PLACE... AND LATEST 11-3.9 MICRON IMAGERY SHOWS PLENTY OF CLOUDS TO THE NORTH DROPPING SOUTH WITH TIME. HOWEVER... THERE ARE INDICATIONS THAT THE BOUNDARY LAYER FLOW WILL BECOME MORE ANTICYCLONIC THIS AFTERNOON... WHICH COULD WORK TO GENERATE SOME DECENT BREAKS IN THE CLOUD COVER. PLAYED THINGS MORE PESSIMISTICALLY FOR NOW GIVEN SATELLITE TRENDS AND FORECAST PROFILES... AND WENT WITH MOSTLY CLOUDY SKIES FOR MUCH OF THE DAY INTO TONIGHT. THE NEXT SHORTWAVE OF INTEREST WILL TAKE A VERY SIMILAR TRACK AS THIS MORNING/S... AND LOOKS TO DROP BY TO OUR SOUTHWEST VERY LATE TONIGHT INTO WEDNESDAY. AT THIS POINT... IT LOOKS LIKE ANY CHANCE FOR PCPN WILL ONCE AGAIN BE CONFINED TO THE FAR SOUTHWEST/SOUTH... AND WILL MAINLY BE ON WEDNESDAY. HOWEVER... DID INCLUDE SOME LOW POPS OVER THE SOUTHWEST FOR VERY LATE TONIGHT AS SOME ISENTROPIC LIFT AND FRONTOGENESIS START TO IMPINGE ON THE AREA. DID NOT MAKE ANY SUBSTANTIVE CHANGES TO THE GOING TEMPERATURE FORECASTS... WHICH WILL ONCE AGAIN BE QUITE A BIT BELOW NORMAL. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 315 AM CDT TUE OCT 22 2013 EARLY MORNING WATER VAPOR IMAGERY WITH 500MB HEIGHTS AND WINDS IDENTIFIED THE BROAD UPPER LEVEL RIDGE ORIENTED ALONG THE WEST COAST OF NORTH AMERICA...WITH A DEEP TROUGH OVER THE GREAT LAKES REGION. THE PV ANOMALY ASSOCIATED WITH THIS VORT MAX WILL DEVELOP A CYCLONE ALONG THE EASTERN SHORE OF JAMES BAY...AND ANOMALOUSLY COLD AIR WILL CONTINUE TO BE DRIVEN SOUTH ACROSS THE UPPER MIDWEST FOR THE NEXT COUPLE OF DAYS. MEANWHILE A TROPICAL PLUME OF MOISTURE ORIGINATING OVER SOUTHERN MEXICO WAS STREAMING NORTHEASTWARD ACROSS THE EASTERN SEABOARD. BY THURSDAY THIS SUBTROPICAL JET WILL PHASE WITH THE NORTHERN STREAM TROUGH AND BOMB OUT A SUB 960MB SURFACE CYCLONE OFF THE COAST OF NEW FOUNDLAND. THIS POWERFUL CYCLONE WILL CAUSE THE NORTHERLY WINDS CURRENTLY IN PLACE ACROSS THE REGION TO BECOME MORE WESTERLY BY THE END OF THE WEEK. FARTHER UPSTREAM SUBSIDENCE WILL LEAD LEE SIDE WARMING ON THE FOOTHILLS OF THE ROCKIES...AND THIS WARM AIR WILL MOVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY BY FRIDAY. IN FACT...THE 22.00 GEM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT THE SATURDAY 00Z RAB AT MSP SHOULD MEASURE ABOVE 0C AT H850. NOT EXACTLY A HEAT WAVE...BUT SLIGHTLY MORE MILD NONE THE LESS. THIS WARM UP WILL BE SHORT LIVED AS ANOTHER SHORTWAVE DRIVING THIS LOW LEVEL WARM AIR ADVECTION WILL CAUSE A CYCLONE TO TRACK ACROSS SOUTHERN CANADA...AND DRIVE A WEAK COLD FRONT THROUGH THE REGION. THIS FRONTAL BOUNDARY WILL EVENTUALLY BECOME ORIENTED EAST/WEST...AND SET THE STAGE FOR A POTENTIALLY SIGNIFICANT STORM SYSTEM TO DEVELOP NEXT WEEK OVER THE MIDWEST. IN SUMMARY...A FEW WEAK WAVED EMBEDDED IN NORTHWEST FLOW WILL KEEP MID LEVEL CLOUDS IN TACT FOR MOST OF THIS WEEK...BUT NOTHING TO MERIT HAVING ANY POPS IN THE FORECAST. TEMPERATURES WILL MODERATE SLIGHTLY BY THE WEEKEND...BUT SHOULD STILL REMAIN BELOW CLIMATOLOGY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1057 PM CDT MON OCT 21 2013 SKIES HAVE CLEARED ACROSS A GOOD PART OF WEST CENTRAL AND CENTRAL MN INTO SOUTHERN MN AND WISCONSIN...BUT NEXT SOUTHWARD SURGE OF CLOUDS SEEMS TO BE TAKING PLACE PER SATELLITE AND OBS. LAMP DATA SUGGEST SOME POTENTIAL FOR MVFR CEILINGS INTO OUR NORTHERN AND EASTERN TAF SITES AFTER 09Z-10Z... AND ESPECIALLY AT KRNH AND KEAU. OBS FROM PARK RAPIDS...BRAINERD INTO NWRN WISC DO SHOW A BROAD AREA OF CEILINGS AROUND O15-025. HAVE ALSO ADDED SOME MVFR AT KAXN BASEED ON OBS EVEN THOUGH MODEL DATA ARE NOT AS BULLISH ON IT. NOT SURE WHAT TO MAKE OF EXPANSIVE MOISTURE TUESDAY EVENING...PATTERN DOES NOT SEEM CONDUCIVE AS SHOULD BE SOME MODEST SUBSIDENCE LATER TUESDAY AFTERNOON INTO THE EVENING. AND IN SW MN...CLIPPER MENTIONED IN SHORT-TERM WILL LIKELY PASS FAR ENOUGH WEST AND SOUTH OF KRWF TO ONLY BRING SOME OVC MID LEVEL CLOUDS. LIGHT SNOW SHOULD BE FARTHER SOUTH AND WEST. FEW FLURRIES AT BEST AT KRWF. KMSP...MOSTLY CLEAR SHORTLY AFTER MIDNIGHT BUT THEN CEILINGS AROUND 045 SHOULD DROP SOUTHWARD AND MAY WELL CLIP KMSP. THIS WILL MOST LIKELY ARRIVE AFTER 11Z. THERE ARE A COUPLE HINTS IN SOME MODEL DATA THAT CEILINGS MAY EVEN DROP TO 2500 OR SO AROUND 11Z...BUT NOT AT ALL CONFIDENT IN THIS...AND HAVE NOT ADDED ANY MVFR CEILINGS. BUT IT IS SOMETHING TO WATCH FOR. /OUTLOOK FOR KMSP/ WED...VFR. SW WIND LESS THAN 5 KT BECMG NW 5-10 KT. THU...VFR. NW WIND 10-15 KT. FRI...VFR. SW WIND 10 KT INCRG TO 15 TO 20 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...99 LONG TERM...JRB AVIATION...TDK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
426 AM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 425 AM CDT TUE OCT 22 2013 MAIN FORECAST CONCERNS WILL BE LIGHT SHOWERS OR SPRINKLES THIS MORNING AND TEMPERATURES. CURRENT RADAR TRENDS SHOW THAT THE SPRINKLES OR LIGHT SHOWERS HAVE MOVED INTO THE SOUTHEAST HALF OR SO OF THE FORECAST AREA EARLY THIS MORNING. SATELLITE SHOWS A FEW BREAKS IN THE CLOUDS...BUT MOSTLY CLOUDY SKIES WILL PERSIST. THE CLOUD COVER HAS HELPED TO KEEP TEMPERATURES A LITTLE ON THE WARMER SIDE. MODELS HAVE HAD SOME LIGHT SHOWERS OR SPRINKLES MOVING THROUGH THE FORECAST AREA DURING THE MORNING. THE NAM AND GFS INDICATE THAT THESE WILL CONTINUE INTO THE MORNING AND BE GONE BY MID DAY...BUT THE HRRR AND 4KM WRF ARE A LITTLE QUICKER TO MOVE THINGS THROUGH THE AREA AND INDICATE THAT THE PRECIPITATION COULD BE DONE AS EARLY AS BY SUN RISE THIS MORNING. WITH THE CURRENT LOCATION OF THE SPRINKLES ON THE RADAR AM INCLINED TO BELIEVE THE SHORT TERM MODELS AND BRING AN EARLY END TO THE PRECIPITATION. BASED ON THE MOVEMENT OF THE PRECIPITATION...THE RETURNS ON THE RADAR AND PRECIPITATION AMOUNTS AS IT MOVES OVER EXPECT THAT SPRINKLES WILL BE THE EXTENT OF THE PRECIPITATION. THE SURFACE PRESSURE GRADIENT TIGHTENS FOR A WHILE THIS MORNING AND THE WINDS AT 850MB ARE 25 TO 35 KTS DURING THE MORNING AND INTO THE AFTERNOON HOURS. EXPECT THERE TO BE BREEZY CONDITIONS DURING THE LATE MORNING INTO EARLY AFTERNOON BEFORE WINDS DIMINISH AS THE SUN GOES DOWN THIS AFTERNOON. CLOUDS WILL BE MORE PREVALENT IN THE NORTHEAST PART OF THE FORECAST AREA AND WILL KEEP TEMPERATURES ON THE LOWER SIDE WHILE A LITTLE MORE SUN AND WARMER TEMPERATURES ALOFT WILL ALLOW FOR SOME WARMER TEMPERATURES IN THE SOUTHWEST. SOME CLOUD COVER WILL CONTINUE ACROSS THE AREA THROUGH THE NIGHT TONIGHT...BUT DESPITE THE CLOUDS TEMPERATURES ACROSS THE AREA WILL BE COOLER THAN TONIGHT AS THE WIND DIMINISHES AND A FEW BREAKS IN THE CLOUDS MOVE THROUGH. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 425 AM CDT TUE OCT 22 2013 BIGGEST CHALLENGE WILL BE DETERMINING TEMPERATURES. THE LONG TERM MODELS CONTINUE TO FORECAST NORTHWEST FLOW AT THE BEGINNING OF THE LONG TERM FORECAST AS WE WILL BE SITUATED BETWEEN A BROAD SYNOPTIC LONGWAVE TROUGH TO THE EAST AND A RIDGE ALONG THE WEST COAST...WITH AN EMBEDDED CUTOFF LOW OFF THE SOUTHERN CALIFORNIA COAST. THE UPPER LEVEL PATTERN WILL BE HIGHLY AMPLIFIED TO BEGIN THE LONG TERM. THERE COULD BE JUST ENOUGH INFLUENCE LEFT FROM A SHORTWAVE TROUGH FORECAST TO GIVE US A SHOT AT SOME LIGHT PRECIPITATION IN OUR FAR NORTHEAST AS THE SHORTWAVE TROUGH DEPARTS TO THE SOUTHEAST. THIS SEEMS TO BE A NEAR COPY OF WHAT HAS HAPPENED OVERNIGHT AND INTO THIS MORNING...EXCEPT ENERGY WILL BE A BIT FARTHER TO THE EAST...LESSENING OUR CHANCES OF MUCH PRECIPITATION AND HAVE KEPT IT OUT OF THE FORECAST...ANTICIPATING THAT ANY PRECIPITATION WILL BE JUST TO THE EAST. MODELS INDICATE CONSIDERABLE HEIGHT RISES BEHIND THE COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED WAVE AND I HAVE INCREASED WIND SPEEDS ACCORDINGLY. FOR THE MOST PART...I KEPT HIGH TEMPERATURES CLOSE TO PREVIOUS FORECASTS. I HAVE LOWERED TEMPERATURES A FEW DEGREES FOR WEDNESDAY NIGHT AS SKY COVER SHOULD BE RELATIVELY SCANT AND WIND SPEEDS SLACKEN. THIS COULD BE THE FIRST HARD FREEZE FOR MANY AREAS OF THE CWA. ALSO...THURSDAY NIGHT COULD BE TRICKY FOR LOW TEMPERATURES AS RETURN FLOW COULD CAUSE TEMPERATURES TO STEADY OUT OR EVEN RISE BY OVERNIGHT...ESPECIALLY SOUTHWEST. IN FACT...OUR SOUTHWEST MAY NOT COOL THAT MUCH AT ALL AS WARM AIR ADVECTION TAKES OVER THERE FIRST. AS A RESULT...LOW TEMPERATURES HAVE BEEN RAISED IN OUR FAR SOUTHWEST TO THE MID 30S TO NEAR 40...WHILE CENTRAL AND EASTERN AREAS WILL HAVE LOWS IN THE MID TO UPPER 20S...AND AGAIN...WITH TEMPERATURES BECOME STEADY OR SLOWLY RISING BY THE OVERNIGHT HOURS. TEMPERATURES WILL BE RATHER SEASONABLE FOR THE MOST PART FOR THE REST OF THE LONG TERM. FRIDAY NIGHT LOOKS LIKE THE WARMEST BEFORE ANOTHER COOL SHOT OF AIR COMES IN WITH ANOTHER WAVE. PATTERN STILL SHOULD BECOME MORE QUASI-ZONAL BY SUNDAY...AS MODELS HAVE BEEN ADVERTISING FOR AWHILE. THIS IS A RESULT OF A MORE SIGNIFICANT SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST. THERE COULD BE A NOTICEABLE WARM-UP IN ADVANCE OF THIS WAVE...BUT I AM GETTING MIXED SIGNALS FROM OPERATION AND ENSEMBLE PREDICTIONS AND I FIND IT BEST TO STICK WITH THE INITIAL ALLBLEND GRIDS. THE FORECAST ESSENTIALLY STAYS DRY THROUGH MONDAY AS TIMING OF THIS WAVE STILL KEEPS IT FAR ENOUGH AWAY TO BRING IN MUCH PRECIPITATION TO OUR AREA AND A COLD FRONT SHOULD BE FAR ENOUGH EAST TO KEEP ANYTHING THAT DEVELOPS ALONG IT TO OUR EAST. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1225 AM CDT TUE OCT 22 2013 LOW TO MID LEVEL CLOUDS WILL MOVE THROUGH THE KGRI TERMINAL AREA THROUGH THE PERIOD. CEILINGS SHOULD REMAIN VFR. THE MAIN QUESTION IS WHETHER THE LIGHT SHOWERS OR SPRINKLES WILL FALL AT THE KGRI TERMINAL. THERE ARE A FEW OUT THERE EARLY THIS MORNING AND THERE COULD BE A FEW DROPS THAT FALL...BUT THAT WOULD BE THE MOST. WINDS WILL BE GUSTY DURING THE MORNING BUT START TO DIMINISH DURING THE LATE AFTERNOON. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...HEINLEIN AVIATION...JCB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
305 AM EDT TUE OCT 22 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE AREA EARLY TUESDAY MORNING. BEHIND THE FRONT MUCH COLDER AIR WILL SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK. CLOUDY AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT RAIN MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW YORK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1230 AM UPDATE...SFC COLD FRONT JUST WEST OF BUFFALO WITH LEADING EDGE OF SHOWERS REACHING THE GENESEE VALLEY ATTM. BASED ON CURRENT RADAR TRENDS AND LATEST MODEL GUIDANCE SLOWED SHOWERS MOVING INTO REGION BY 2-3 HOURS. SHOWERS WILL REACH WESTERN FA BY 07Z-08Z, CENTRAL FA 10Z-12Z AND EASTERN SECTIONS 12Z-14Z. WILL CONTINUE WITH LIKELY/CAT POPS FOR MUCH OF CENTRAL NY AND CHC/SLIGHT CHC FOR NE PA. 715 PM UPDATE... NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS SRN ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO. PCPN IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES NMM INDICATES THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT 06Z AND MAY NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT UNTIL NEXT UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY TEMPS RIGHT ON TARGET AT THIS TIME. PREV DISCUSSION BLO... BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY. FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE 40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY. MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... 3 AM UPDATE... GRIDS ADJUSTED TO ACCOUNT FOR WPC AND MODEL TRENDS. LITTLE CHANGE. UPPER TROUGH PATTERN LATE WEEK INTO WEEKEND...LOOKS TO SHIFT TEMPORARILY INTO A FLATTER W OR WSW FLOW ALOFT BY EARLY NEXT WEEK. THIS WILL ALLOW TEMPERATURES TO EDGE UP CLOSER TO CLIMATOLOGY...AND A BREAK IN PRECIPITATION CHANCES SUNDAY NIGHT THROUGH AT LEAST MONDAY NIGHT. UNTIL THEN...UNSETTLED CHILLY CYCLONIC FLOW WITH GREAT LAKES HELPING TO YIELD SCATTERED -SHRA/-SHSN MAINLY IN CENTRAL NY. PREVIOUS DISCUSSION... LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... 06Z UPDATE... MAIN WEATHER FEATURE OF INTEREST IS A COLD FRONT SET TO MOVE WEST TO EAST ACROSS THE TERMINALS 10Z-15Z...AND A VFR CIG HAS ALREADY FORMED AHEAD OF IT. FRONT WILL COME THROUGH WITH LIMITED MOISTURE...THUS ONLY KNOCKING TERMINALS /EXCEPT KAVP/ DOWN TEMPORARILY INTO MVFR WITH FRONTAL PASSAGE AND LIGHT SHOWERS. SEE TAFS FOR SPECIFIC TIMING. BRIEF FUEL ALTERNATE MVFR ALSO POSSIBLE HILLTOP TERMINALS KBGM-KITH. WINDS TO VEER FROM S-SSW TO W-WNW AS FRONT PASSES. 4-5 KFT AGL CIG LATE MORNING-EARLY AFTERNOON...THEN DRYNESS OF AIR MASS WILL SCATTER THINGS OUT BY LATE AFTERNOON INTO EVENING. OUTLOOK... LATE TUE NGT...VFR. WED/THU/FRI/SAT...TIMES OF MVFR CIGS AND SCT -SHRA MAINLY CENTRAL NY TERMINALS WITH MOISTURE OFF OF GREAT LAKES. -SHSN MAY MIX IN AT TIMES LATE NIGHT-EARLY MORNING. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...JAB NEAR TERM...JAB/PVN/RRM SHORT TERM...JAB LONG TERM...MDP AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
149 AM EDT TUE OCT 22 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE AREA EARLY TUESDAY MORNING. BEHIND THE FRONT MUCH COLDER AIR WILL SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK. CLOUDY AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT RAIN MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW YORK. && .NEAR TERM /THROUGH TODAY/... 1230 AM UPDATE...SFC COLD FRONT JUST WEST OF BUFFALO WITH LEADING EDGE OF SHOWERS REACHING THE GENESEE VALLEY ATTM. BASED ON CURRENT RADAR TRENDS AND LATEST MODEL GUIDANCE SLOWED SHOWERS MOVING INTO REGION BY 2-3 HOURS. SHOWERS WILL REACH WESTERN FA BY 07Z-08Z, CENTRAL FA 10Z-12Z AND EASTERN SECTIONS 12Z-14Z. WILL CONTINUE WITH LIKELY/CAT POPS FOR MUCH OF CENTRAL NY AND CHC/SLIGHT CHC FOR NE PA. 715 PM UPDATE... NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS SRN ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO. PCPN IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES NMM INDICATES THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT 06Z AND MAY NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT UNTIL NEXT UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY TEMPS RIGHT ON TARGET AT THIS TIME. PREV DISCUSSION BLO... BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY. FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE 40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY. MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... 06Z UPDATE... MAIN WEATHER FEATURE OF INTEREST IS A COLD FRONT SET TO MOVE WEST TO EAST ACROSS THE TERMINALS 10Z-15Z...AND A VFR CIG HAS ALREADY FORMED AHEAD OF IT. FRONT WILL COME THROUGH WITH LIMITED MOISTURE...THUS ONLY KNOCKING TERMINALS /EXCEPT KAVP/ DOWN TEMPORARILY INTO MVFR WITH FRONTAL PASSAGE AND LIGHT SHOWERS. SEE TAFS FOR SPECIFIC TIMING. BRIEF FUEL ALTERNATE MVFR ALSO POSSIBLE HILLTOP TERMINALS KBGM-KITH. WINDS TO VEER FROM S-SSW TO W-WNW AS FRONT PASSES. 4-5 KFT AGL CIG LATE MORNING-EARLY AFTERNOON...THEN DRYNESS OF AIR MASS WILL SCATTER THINGS OUT BY LATE AFTERNOON INTO EVENING. OUTLOOK... LATE TUE NGT...VFR. WED/THU/FRI/SAT...TIMES OF MVFR CIGS AND SCT -SHRA MAINLY CENTRAL NY TERMINALS WITH MOISTURE OFF OF GREAT LAKES. -SHSN MAY MIX IN AT TIMES LATE NIGHT-EARLY MORNING. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...JAB NEAR TERM...JAB/PVN/RRM SHORT TERM...JAB LONG TERM... AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1232 AM EDT TUE OCT 22 2013 .SYNOPSIS... A LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL TRACK INTO QUEBEC TONIGHT. SHOWERS WILL ACCOMPANY A COLD FRONT MOVING THROUGH THE AREA EARLY TUESDAY MORNING. BEHIND THE FRONT MUCH COLDER AIR WILL SPREAD OVER THE NORTHEAST FOR THE REMAINDER OF THE WEEK. CLOUDY AND SHOWERY CONDITIONS CAN BE EXPECTED...WITH LAKE EFFECT RAIN MIXING WITH SNOW OVER THE HIGHER TERRAIN IN NORTH CENTRAL NEW YORK. && .NEAR TERM /THROUGH TODAY/... 1230 AM UPDATE...SFC COLD FRONT JUST WEST OF BUFFALO WITH LEADING EDGE OF SHOWERS REACHING THE GENESEE VALLEY ATTM. BASED ON CURRENT RADAR TRENDS AND LATEST MODEL GUIDANCE SLOWED SHOWERS MOVING INTO REGION BY 2-3 HOURS. SHOWERS WILL REACH WESTERN FA BY 07Z-08Z, CENTRAL FA 10Z-12Z AND EASTERN SECTIONS 12Z-14Z. WILL CONTINUE WITH LIKELY/CAT POPS FOR MUCH OF CENTRAL NY AND CHC/SLIGHT CHC FOR NE PA. 715 PM UPDATE... NO CHGS NEEDED TO GRIDS AT THIS TIME. SFC LOPRES TRACKING ACRS SRN ONTARIO AT THIS TIME WITH ATTENDANT CDFNT DRAPED ACRS OHIO. PCPN IS SLOWLY TREKING EAST ALONG IT. LATEST RUN OF HRRR AND HIRES NMM INDICATES THIS LINE OF PCPN SHUD NOT HIT WRN ZONES UNTIL AFT 06Z AND MAY NEED TO ADJUST TIMING BACK BY AN HR OR TWO BUT WL WAIT UNTIL NEXT UPDATE. OVRNGT MINS LOOK TO BE REASONABLE WITH HRLY TEMPS RIGHT ON TARGET AT THIS TIME. PREV DISCUSSION BLO... BROAD SOUTHWEST FLOW AHEAD OF A CLOSED LOW MOVING ACROSS SOUTHERN CANADA WILL CONTINUE THROUGH THIS EVENING. A SURFACE COLD FRONT APPROACHING FROM THE WESTERN LAKES LOOKS TO MOVE INTO THE REGION VERY LATE IN THIS PERIOD. THE MAIN FOCUS TO FORECAST ADJUSTMENTS IS TO GRADUALLY SLOW THE ONSET OF RAINFALL WITH THIS FEATURE AS THE PATTERN IS SUGGESTING MAINLY ANA-FRONTAL CHARACTERISTICS WITH PRECIP MAINLY ALONG AND BEHIND THE FRONT AS SUPPORTING ENERGY ALOFT RIDES PARALLEL TO THE BOUNDARY. THE PREVIOUS FORECAST WAS HANDLING THIS TREND WELL...SO ONLY MADE AN HOUR OR TWO TIMING ADJUSTMENT. GIVEN THE INCRG CLOUDS AND MIXING FROM AN ACTIVE WIND FIELD...THE TEMPS SHOULD REMAIN FAIRLY MILD OVERNIGHT IN THE 40S. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... THE PERIOD OF RAINFALL ASSOCIATED WITH THE FRONTAL PASSAGE LOOKS TO BE FAIRLY BRIEF FOR ANY ONE LOCATION WITH ABOUT 2-4 HOURS WORTH OF RAIN EARLY TUESDAY MORNING BEFORE THE FRONT SWEEPS EAST WITH SINKING MOTION AND DRYING WORKING ACROSS THE AREA DURING BY EARLY AFTERNOON. AS THE FRONT MAKES IT/S WAY EAST...WE HAVE NOTED TRENDS IN THE SYSTEM WEAKENING AS IT MOVES FROM THE FINGER LAKES TO THE CATSKILLS. IN ADDITION TO QUICKLY MOVING POP TRENDS ACROSS THE AREA...WILL ALSO DIMINISH THE CHANCES WITH TIME AND IN FACT...THERE LOOKS TO BE VERY LITTLE ASIDE FROM SCATTERED ACTIVITY OVER OUR SOUTHERN ZONES. ALSO...WITH THE FLOW SHIFTING TO THE WSW-W...THERE MAY EVEN BE A FAIR AMOUNT OF BREAKS IN THE CLOUDS DEVELOPING WITH AREAS OF SUNSHINE DURING THE LATTER PART OF THE DAY. FROM TUESDAY NIGHT THROUGH THURSDAY...THE PATTERN REMAINS VERY ACTIVE WITH THE ATMOSPHERE ALSO COOLING AND BECOMING CONDITIONALLY UNSTABLE TO LAKE EFFECT THRESHOLDS. TEMPERATURES LOOK TO BE BRIEFLY BELOW NORMAL WITH HIGHS POSSIBLY NOT CLIMBING OUT OF THE 40S ON WEDS-THURS. INITIALLY...ANY LAKE DEVELOPMENT OF SHOWERS OR FLURRIES WILL REMAIN TO OUR NORTH ON TUESDAY NIGHT...BUT SHIFTING FLOW TO THE WEST AND NORTHWEST BEGINS TO TARGET OUR NORTHERN COUNTIES AS WE HEAD INTO WEDNESDAY THROUGH THURSDAY. THE PASSAGE OF SEVERAL WAVES UP UPPER ENERGY WILL CAUSE FLUCTUATIONS IN THE BOUNDARY LAYER STEERING FLOW WITH ANY BANDING OF RAIN/SNOW SHOWERS OSCILLATING ACROSS THE EASTERN LAKES AND MOHAWK VALLEY. MUCH OF THE PRECIPITATION THAT FALLS IS FORECAST TO BE LIGHT ACROSS THE REGION WITH AMOUNTS GENERALLY SUFFICIENT TO MAINLY WETTING THE PAVEMENT. ORGANIZED BANDS EAST OF THE LAKES COULD CONTRIBUTE TO A BIT MORE. BOUNDARY LAYER...AND SURFACE TEMPERATURES LATER WEDNESDAY NIGHT MAY BE SUFFICIENT FOR THE FIRST MINOR SNOW ACCUMULATIONS OF THE SEASON WHICH WOULD BE AT ELEVATIONS SUCH AS THE TUG HILL OR TULLY-HEIBERGS OF CNY. EARLY THOUGHTS ON THIS RIGHT NOW SUGGEST AN INCH OR LESS ON GRASSY SURFACES BY THURSDAY MORNING. ELSEWHERE...GENERALLY RAIN SHOWERS CAN BE EXPECTED FROM TIME TO TIME WITH WET FLAKES MIXED IN ACROSS CNY AND NORTHERN PA. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... LTL CHG TO PREV FCST WITH UNSETTLED AND MUCH COOLER CONDITIONS DUE TO LAKE EFFECT SHRA/SHSN AND PASSING S/WV`S OR CLIPPER TYPE SYSTEMS. UPR HGTS BEGIN TO RISE LATE IN THE PD AS SFC HI PRES BUILDS IN FROM THE OH VLY OFFERING HOPE FOR SOME RELIEF BY MON. TIMING OF THE WAVES AND LOW LVL FLOW ORIENTATION FOR LE PCPN TUFF TO PINPOINT AT THIS TIME FRAME BUT THERE APPEARS TO BE SOME AGREEMENT THAT LOW LVL FLOW WILL BGM MORE NWLY ON FRI...ALLOWING ACTIVITY TO DROP SWD INTO CNTRL NY. USED WPC MED RNG GDNC AS A START...WITH SOME ENHANCEMENTS TO CLD/POP GRIDS MAINLY DAYS 4-5. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... 00Z UPDATE... VFR CONDITIONS WILL PREVAIL THROUGH THE EARLY EVENING AHEAD OF AN APPROACHING COLD FRONT FROM THE WEST. WINDS WILL WEAKEN QUICKLY AFTER SUNSET AS WE LOSE MIXING FROM THE SUN AND REMAIN UNDER 12 KNOTS. THE COLD FRONT WILL MOVE FROM W TO E EARLY TUESDAY MORNING FORCING THE WINDS TO TRANSITION FROM A SOUTHERLY FLOW TO A WEST/NORTHWESTERLY FLOW. LIGHT RAIN SHOWERS WILL ACCOMPANY THIS FRONT AND CAUSE RESTRICTIONS OF MVFR CIGS AND VISBYS AT KRME... KSYR... AND KITH THROUGH 15Z TUESDAY MORNING. THE REMAINING TAFS SITES ARE EXPECTED TO REMAIN VFR AS THE FRONT PASSES WITH LIGHT RAIN SHOWERS. WINDS TUESDAY AFTERNOON WILL PICK UP CAUSING LINGERING MVFR CIGS TO LIFT TO VFR. OUTLOOK... TUE NGT...VFR. WED/THU/FRI/SAT...MVFR AND OCNL IFR IN -SHRA/-SHSN....MAINLY ACRS CNTRL NY AFFECTING RME/SYR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...JAB NEAR TERM...JAB/PVN/RRM SHORT TERM...JAB LONG TERM... AVIATION...KAH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
422 AM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 422 AM CDT TUE OCT 22 2013 CLIPPER SYSTEM MOVING ACROSS THE AREA THIS MORNING. LOOKS LIKE ENOUGH UPPER LEVEL ENERGY HANGS AROUND TO KEEP THE PRECIPITATION GOING A BIT LONGER THIS MORNING THAN PREVIOUSLY FORECAST. NAM...HRRR AND RAP ALL SUGGEST LIGHT PRECIPITATION WILL LINGER THROUGH 15Z IN SIOUX FALLS AND 17Z OR SO ACROSS PORTIONS OF NORTHWEST IOWA. WOULD EXPECT THIS TO BE PREDOMINATELY LIGHT SNOW ALONG AND NORTHEAST OF A HURON TO SIOUX FALLS TO SPENCER IOWA LINE...WITH A FEW SNOWFLAKES EVEN POTENTIALLY MIXING IN AS FAR SOUTH AS AREAS JUST NORTH OF THE MISSOURI RIVER. THE AFTERNOON HOURS WILL BE DRY...WITH SKIES BECOMING PARTLY SUNNY. EXPECTING GOOD MIXING AGAIN...AND BASED ON HOW WARM WE WERE ABLE TO GET YESTERDAY...WENT AHEAD AND BUMPED HIGHS UP A FEW DEGREES FOR TODAY...MAINLY LOW AND MID 40S. ANOTHER CLIPPER SYSTEM WILL DROP SOUTHEAST TOWARDS THE AREA LATER TONIGHT INTO WEDNESDAY. TEMPERATURES TONIGHT ARE TRICKY. WITH CALM WINDS LOCATIONS IN THE EAST SHOULD DROP RAPIDLY IN THE EVENING HOURS. MEANWHILE AS CLOUDS INCREASE FROM WEST TO EAST TEMPERATURES WILL BEGIN TO RISE. TRIED TO SHOW THIS IN THE GRIDS...BUT WOULD NOT BE SURPRISED IF LOCATIONS EATS OF INTERSTATE 29 END UP A BIT COLDER THAN CURRENTLY FORECAST. THE CLIPPER SYSTEM ITSELF SEEMS TO BE TRENDING SOUTHWEST. FOLLOWING A CONSENSUS OF THE NAM...GFS...ECMWF AND HI RES MODELS SEEMS LIKE A GOOD CALL AT THIS POINT. OVERALL WOULD THINK THE OVERALL EVOLUTION WILL BE SIMILAR TO WHAT HAPPENED WITH THE CURRENT SYSTEM...A BROAD AREA OF LIGHT PRECIP AND A EMBEDDED BAND OF HIGHER QPF ASSOCIATED WITH MID LEVEL FRONTOGENESIS. 500 TO 300 MB Q VECTOR CONVERGENCE A BIT STRONGER WITH THE SYSTEM TONIGHT...LIKELY OWING TO A STRONGER UPPER JET. SO WOULD NOT BE SURPRISED IF QPF AMOUNTS END UP A BIT HIGHER OVERALL. PRECIPITATION TYPE IS AGAIN AN ISSUE. LOOKS PRETTY SIMILAR TO THIS MORNINGS EVENT IN THAT AN AREA OF SNOW WILL BE LIKELY ON THE NORTHERN EDGE OF THE BAND. BOUNDARY LAYER IS A BIT WARMER...SUGGESTING THE AREA THAT SEES MAINLY SNOW WILL PROBABLY BE PRETTY SMALL. AGAIN ONLY THINKING WE SEE A COATING TO AN INCH OF ACCUMULATION. WOULD THINK ANYWHERE ALONG AND NORTHEAST OF A HURON TO SIOUX FALLS TO SIOUX CITY LINE WOULD SEE THE BEST CHANCE OF THIS LIGHT ACCUMULATION. WILL CONTINUE TO MONITOR TRENDS...AS IF THINGS WORKS OUT JUST RIGHT...COULD SEE A NARROW AREA OF 1 TO 2 INCHES OF SNOW...BUT GIVEN THE MARGINAL THERMAL PROFILE AND QPF PLACEMENT UNCERTAINTY...CONFIDENCE REMAINS LOW. STILL SOME TIMING DIFFERENCES AS WELL...BUT GENERALLY LOOKS LIKE THE PRECIP WILL ENTER OUR WEST AROUND 08Z AND APPROACH INTERSTATE 29 AROUND 11Z. PRECIP WILL EXIT BY LATE MORNING OR EARLY AFTERNOON. SKIES WILL REMAIN MOSTLY CLOUDY THROUGH THE AFTERNOON...WITH ANOTHER DAY OF HIGHS ONLY IN THE 40S. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 422 AM CDT TUE OCT 22 2013 LESS ACTIVE PATTERN RETURNS TO THE AREA WEDNESDAY NIGHT AS WAVE EXITS TO THE SOUTHEAST. STILL IN COOL NORTHWEST FLOW INTO THURSDAY...SO WELL BELOW NORMAL TEMPERATURES WILL STICK AROUND FOR ONE MORE DAY. ANTICIPATE FAIR AMOUNT OF HEATING-DRIVEN CUMULUS IN OUR NORTHEAST THURSDAY AFTERNOON BASED ON FORECAST SOUNDINGS...WITH SOME MODELS SQUEEZING OUT A FEW SPRINKLES. HAVE NOT INCLUDED ANY PRECIP MENTION AT THIS TIME...BUT EVEN IF THEY DO OCCUR...SHOULD BE SPOTTY AND VERY LIGHT. NORTHWEST WINDS BECOMING GUSTY WITH THE GOOD MIXING AS WELL... WITH BOTH CLOUDS AND WIND DIMINISHING IN THE EVENING AS SURFACE RIDGE PUSHES INTO THE CWA FROM THE WEST. TEMPERATURES WEDNESDAY NIGHT AND THURSDAY NIGHT LIKELY TO BE IN THE MID-UPPER 20S MOST AREAS...WITH HIGHS THURSDAY AGAIN IN THE 40S. LONGER RANGE FRIDAY THROUGH MONDAY FEATURES WESTERN CONUS RIDGE NUDGING EASTWARD THROUGH THE WEEKEND. STRONG WARMING ALOFT ON FRIDAY NOT LIKELY TO BE FULLY REALIZED AT THE SURFACE...THOUGH MOST AREAS SHOULD AT LEAST WARM BACK INTO THE 50S...WITH SOME LOWER 60S NOT OUT OF THE QUESTION IN OUR SOUTHWEST. UPPER WAVE DROPPING FROM CENTRAL CANADA INTO THE WESTERN GREAT LAKES FRIDAY NIGHT/SATURDAY WILL DRAG A COOL FRONT SOUTHEAST THROUGH THE NORTHERN PLAINS. MODELS NOW TRENDING BACK TOWARD HOLDING THE COLDEST OF AIR WITH THIS SYSTEM NORTHEAST OF OUR AREA...THOUGH WILL LIKELY STILL SEE HIGHS SATURDAY KNOCKED BACK A FEW DEGREES FROM FRIDAYS READINGS...UPPER 40S IN SOUTHWEST MINNESOTA TO MID 50S IN OUR SOUTHWEST. ANOTHER PUSH OF WARMER AIR ALOFT SHOULD HELP HIGHS SUNDAY CLIMB BACK INTO THE 50S TO MAYBE LOWER 60S. THIS AHEAD OF STRONGER WAVE SLATED TO AFFECT THE REGION EARLY NEXT WEEK. MODELS DIFFERING ON TIMING SLIGHTLY...WITH GFS FASTER/COOLER THAN ECMWF BY LATE MONDAY...THOUGH BOTH MODELS CURRENTLY HOLD OFF BETTER PRECIP CHANCE FOR MOST OF OUR AREA UNTIL MONDAY NIGHT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1006 PM CDT MON OCT 21 2013 DEVELOPMENT OF MVFR CEILINGS ON TRACK AS PRECIPITATION BAND WORKS INTO THE AREA LATE EVENING. WILL CONTINUE TO SEE SOUTHEAST SPREAD IN MVFR CEILINGS...AND WITH RAIN MIXING WITH OR CHANGING TO SNOW FOR KHON/KFSD AREAS EASTWARD...WILL SEE PERIODS OF IFR VISIBILITIES AND CEILINGS AS WELL. EVENTUALLY...CEILINGS WILL BEGIN TO LIFT AS FLOW TURNS NORTHERLY AND DRIVES LOWER LEVEL DRY AIR SOUTHWARD DURING THE MORNING HOURS. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...JH AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
341 AM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT TUE OCT 22 2013 AT 3 AM...A BAND OF LIGHT RAIN AND SNOW EXTENDED FROM CENTRAL IOWA NORTHWEST TO SOUTHEAST SOUTH DAKOTA. THIS PRECIPITATION IS LOCATED IN AN AREA OF 900 TO 700 MB FRONTOGENESIS THAT HAS DEVELOP AHEAD OF A SHORT WAVE TROUGH LOCATED OVER EASTERN SOUTH DAKOTA. THE MESO MODELS SUGGEST THAT THIS FORCING ALONG WITH THE 280-290K ISENTROPIC LIFT WILL REMAIN JUST SOUTH AND WEST OF THE FORECAST AREA. IN ADDITION WITH THE 280-290K CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN 20 AND 50 MB...THERE MAY BE SOME SATURATION ISSUES IN NORTHEAST IOWA. RAP BUFKIT SOUNDINGS SHOW THAT THERE WILL BE A VERY BRIEF PERIOD WHERE THE OMEGA WILL INTERSECT THE DEDRITIC GROWTH ZONE...BUT ALSO AT THIS TIME THERE IS STILL QUITE A BIT OF DRY AIR BELOW 800 MB. IT DEFINITELY LOOKS BETTER AS ONE HEADS SOUTH TO WATERLOO IOWA. DUE TO THIS...KEPT A 20 TO 40 PERCENT CHANCE OF RAIN AND SNOW BORDERING THE DES MOINES AND DAVENPORT COUNTY WARNING AREAS BETWEEN 22.10Z AND 22.20Z. THESE TIMES WERE BASED ON THE MESO MODELS. LIQUID AMOUNTS WILL BE LESS THAN A TENTH OF AN INCH AND SNOW AMOUNTS WILL BE LESS THAN A HALF INCH SOUTH OF A ST ANSGAR IOWA TO PLATTEVILLE WISCONSIN. FOR THIS EVENING...THE MODELS CONTINUE TO SHOW STEEP /7 TO 7.5 C/KM/ SURFACE TO 700 MB LAPSE RATES ACROSS THE FORECAST AREA. THIS WILL LIKELY KEEP SOME MID CLOUDS ACROSS THE FORECAST AREA. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 340 AM CDT TUE OCT 22 2013 ON WEDNESDAY...THE 22.00Z MODELS SHOW THAT ANOTHER SHORT WAVE TROUGH WILL MOVE SOUTHEAST ACROSS WESTERN AND SOUTHERN IOWA. AS A RESULT...MUCH OF THE FRONTOGENETIC FORCING AND 280-290K ISENTROPIC LIFT STAY WELL WEST AND SOUTH OF THE FORECAST AREA. WITH NOT MUCH LIFT AND 280-290K CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN 30 AND 50 MB... TOOK OUT THE PRECIPITATION CHANCES OUT OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN. LIKE THE 21.12Z MODELS...THE 22.00Z MODELS ARE CONTINUING TO TREND THAT THAT THE WESTERN PERIPHERY OF THE LONG WAVE TROUGH OVER EASTERN CANADA WILL SHIFT A BIT FURTHER EAST AND THIS WILL SHIFT THE STORM TRACK INTO THE MINNESOTA ARROWHEAD AND EASTERN WISCONSIN. AS RESULT...IT DOES NOT LOOK LIKE WE WILL SEE ANOTHER SURGE OF COLD INTO THE REGION FOR THE WEEKEND. THIS WILL ALLOW TEMPERATURES TO WARM CLOSER TO NORMAL. IN ADDITION...PRECIPITATION CHANCES LOOK TO MAINLY TO OUR NORTH AND EAST. HOWEVER CANNOT COMPLETELY TAKE OUT THE PRECIPITATION CHANCES ACROSS NORTH CENTRAL WISCONSIN...SO KEPT A 20 PERCENT CHANCE OF RAIN AND SNOW IN TAYLOR COUNTY FOR FRIDAY NIGHT INTO SATURDAY. LOOKING AHEAD TO EARLY NEXT WEEK...THE MODELS ARE NOW SHOWING THAT THE WESTERN RIDGE WILL RETROGRADE WEST AND THAT A LONG WAVE TROUGH WILL DEVELOP OVER THE INTER MOUNTAIN REGION. AS THIS OCCURS... THE UPPER LEVEL WINDS WILL SHIFT TO THE WEST AND SOUTHWEST. THIS WILL ALLOW EVEN WARMER AIR AIR TO MOVE BACK INTO THE AREA. THIS COULD BE OUR FIRST TASTE OF INDIAN SUMMER. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1151 PM CDT MON OCT 21 2013 VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS A WEATHER SYSTEM TRAVELS SOUTH OF THE TAFS. PROLONGED NORTHWEST FLOW AND THE WEATHER SYSTEM IN IOWA WILL WILL BRING CLOUDS OF THE VFR VARIETY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1152 PM CDT MON OCT 21 2013 .UPDATE... ISSUED AT 938 PM CDT MON OCT 21 2013 HAVE BEEN FOLLOWING THE TRENDS OF THE HRRR AND RAP ALL EVENING AND THE 22.00Z NAM HAS NOW COME IN AS WELL...ALL WITH THE SNOW STRIPE FURTHER SOUTH IN IA BY 1-2 COUNTIES. HAVE TRENDED THE FORECAST THAT WAY WITH REDUCED PRECIPITATION CHANCES...AND LESS SNOWFALL /NOW ABOUT 0.5 INCHES VERSUS 1 INCH/ IN FAR SOUTH. WITH CLEAR SKIES AND SOME LOW-LEVEL RIDGING AND LIGHT WIND...HAVE ALSO COOLED LOW TEMPERATURES ACROSS THE SOUTH TOO. FORECAST SHOULD BE UP TO THE WEB SITE AND IN PRODUCTS SHORTLY. UPDATE ISSUED AT 702 PM CDT MON OCT 21 2013 HAVE BEEN MONITORING CURRENT CONDITIONS ACROSS THE DAKOTAS AND INTO IOWA...AS WELL AS MODEL FORECASTS WITH THE SNOW SWATH COMING THROUGH IA/MN LATER TONIGHT. OVERALL OPINION IS THAT THIS WILL BE A PRETTY NARROW BAND OF INTENSE LIFT WITH THE HIGHEST PROBABILITY OF SNOW TO THE SOUTH OF THE FORECAST AREA. LATEST HRRR RUNS ARE SLOWING THE ONSET OF THE SNOW JUST SOUTH OF THE FORECAST AREA...BUT REALLY AGREE WELL WITH THE LATEST RUC RUNS AND 21.18Z NAM. THIS WILL BE A CLOSE ONE...WITH THE BAND AFFECTING WATERLOO AND DUBUQUE. 21.18Z NAM COBB DATA SUGGESTS ABOUT 5 INCHES OF SNOWFALL THERE...BUT THIS DOES NOT TAKE INTO ACCOUNT MELTING. 21.18Z GFS COBB MUCH MORE TAME WITH ABOUT AN INCH. SNOW RATES IN THE BAND WILL CAUSE ACCUMULATIONS AND SEEMS DMX/DVN WITH A 1-3 INCH BAND SEEMS RIGHT FROM SIOUX FALLS SD TO THE QUAD CITIES IA. OELWEIN TO NORTH DUBUQUE HAVE THE BEST CHANCE OF SEEING AN INCH IN THE LA CROSSE FORECAST AREA. FORECAST ACROSS THE SOUTH LOOKS GOOD AND HAVE NOT CHANGED IT AT THIS TIME. HAVE DECREASED CLOUDS FOR THE EVENING WITH CLEARING WORKING IN SOUTH OF I-94. WINDS WILL DROP OFF QUICKLY THIS EVENING AND THINKING THERE WILL BE ENOUGH TO HOLD TEMPS ABOVE DEWPOINTS BEFORE CLOUDS ARRIVE FROM THE WEST. BUT...FOG HAS CROSSED MY MIND WEST OF MISS RIVER WHERE SURFACE RIDGING IS BUILDING IN. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 307 PM CDT MON OCT 21 2013 THE MAIN FOCUS FOR TONIGHT INTO TOMORROW IS WITH THE CHANCES FOR AN ACCUMULATING SNOW ACROSS NORTHEAST IOWA. CURRENTLY...A CLOSED MID LEVEL LOW IS DRIFTING EAST ACROSS NORTHERN MINNESOTA WHILE A BROAD SURFACE LOW IS CENTERED OVER EASTERN ONTARIO. THE BROAD CYCLONIC FLOW EXTENDS ACROSS MUCH OF THE UPPER MISSISSIPPI RIVER VALLEY AND HAS LEAD TO AN EXTENSIVE STRATOCUMULUS FIELD THAT ALSO HAS PRODUCED SOME OCCASIONAL VERY LIGHT FLURRIES. THE MORE INTENSE SNOW SHOWERS HAVE BEEN FURTHER NORTH CLOSER TO THE CLOSED MID LEVEL LOW AND SURFACE INVERTED TROUGH NEAR LAKE SUPERIOR. GIVEN THE CELLULAR LOOK TO THE CLOUDS AND THAT WEAK SURFACE HIGH PRESSURE WILL BE MOVING IN...SOME CLEARING MAY TAKE PLACE FOR A PERIOD THIS EVENING BEFORE THE NEXT SYSTEM MOVES IN AND BRINGS HIGH LEVEL CLOUD COVER IN WITH IT. THIS NEXT SYSTEM IS CURRENTLY IN SOUTH CENTRAL CANADA AND WILL DIVE SOUTHEAST ACROSS THE DAKOTAS ON INTO IOWA TONIGHT INTO TOMORROW MORNING. A NARROW BAND OF PRECIPITATION WILL ACCOMPANY THIS LOW WITH THE BEST LOW LEVEL FRONTOGENESIS STAYING JUST SOUTHWEST OF THE FORECAST AREA IN CENTRAL/EASTERN IOWA. THE 21.12Z MODEL SUITE IS ALL IN GOOD AGREEMENT WITH THE TIMING/TRACK OF THIS SYSTEM WITH SOME LIGHT PRECIPITATION MAKING IT INTO NORTHEAST IOWA...MAINLY FROM CHARLES CITY TO OELWEIN. THERMAL PROFILES SHOW THAT THERE IS ICE PRESENT THROUGHOUT THE EVENT AND THAT IT WILL BE COLD ENOUGH TO BE ALL SNOW AS WELL. WITH THE BETTER FORCING TO THE SOUTH...ONLY EXPECT SOME VERY MINOR ACCUMULATIONS AT A HALF INCH OR LESS IN THAT CHARLES CITY TO OELWEIN CORRIDOR. THE MAIN PERIOD FOR THIS SNOW APPEARS TO BE BETWEEN ABOUT 3AM AND 9AM TUESDAY MORNING BEFORE THE SYSTEM TRACKS TO THE SOUTHEAST OF THE REGION. TEMPERATURES WILL TEMPORARILY IMPROVE FOR A BRIEF PERIOD TUESDAY AS 850MB TEMPERATURES GO FROM AROUND -8C AT PRESENT UP TO -4C BEFORE THE NEXT COLD SURGE DROPS THEM BACK DOWN TO AROUND -8C IN THE AFTERNOON. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 307 PM CDT MON OCT 21 2013 ANOTHER MID LEVEL SHORT WAVE TROUGH WILL DIVE SOUTH ALONG THE WESTERN PERIPHERY OF THE LONG WAVE TROUGH THAT IS STUCK ACROSS THE NORTHEASTERN US AND EASTERN CANADA ON WEDNESDAY. THIS WILL BRING ANOTHER SURFACE LOW WITH PRECIPITATION THROUGH CENTRAL IOWA WITH THE QUESTION BEING WHETHER ANY OF IT WILL GET INTO NORTHEAST IOWA. THE TREND APPEARS TO BE TAKING THIS ONE FURTHER TO THE SOUTH THAN THE LOW COMING THROUGH TONIGHT. THERE IS ENOUGH OF A POSSIBILITY THAT SOME OF THIS PRECIPITATION COULD GET INTO NORTHEAST IOWA...SO HAVE LEFT SOME SMALL CHANCES FOR A SNOW CHANGING TO RAIN MIX IN THERE. WITH THIS SYSTEM COMING THROUGH THE REGION MORE SO DURING THE DAY THAN OVERNIGHT...SURFACE TEMPERATURES WILL LIKELY WARM ENOUGH TO CAUSE THAT CHANGE OVER. THE REST OF THE WEEK LOOKS TO STAY ON THE COLD SIDE WITH 850MB TEMPERATURES IN THE -6C TO -8C RANGE UNTIL FRIDAY WHEN SOME LOW LEVEL WARM ADVECTION FINALLY KICKS IN AS THE UPPER TROUGH BREAKS DOWN AND SHIFTS EAST. THE WAA WILL BEGIN AS ANOTHER SHORT WAVE DIVES INTO THE GREAT LAKES FRIDAY/SATURDAY. THE 21.12Z GFS IS A TAD FASTER WITH THIS FEATURE THAN THE 21.12Z ECMWF AND BRINGS TEMPS BACK DOWN A BIT FASTER AS WELL. IF THE ECMWF PANS OUT...HIGHS ON SATURDAY COULD BE A LITTLE HIGHER IN THE 50S...PARTICULARLY IN NORTHEAST IOWA/SOUTHWEST WISCONSIN. THE LONG TERM GUIDANCE HAS THEN COME AROUND TO SHOW SOME BROAD TROUGHING DEVELOPING IN THE NORTHWESTERN US WHICH WILL LEAD TO AN ELONGATED SURFACE LOW FORMING ACROSS THE CENTRAL PLAINS SUNDAY NIGHT INTO MONDAY. THIS FEATURE WILL BE OUR NEXT SHOT FOR A WIDESPREAD RAIN EVENT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT) ISSUED AT 1151 PM CDT MON OCT 21 2013 VFR CONDITIONS EXPECTED THROUGH THE PERIOD AS A WEATHER SYSTEM TRAVELS SOUTH OF THE TAFS. PROLONGED NORTHWEST FLOW AND THE WEATHER SYSTEM IN IOWA WILL WILL BRING CLOUDS OF THE VFR VARIETY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...HALBACH LONG TERM...HALBACH AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
1031 AM EDT TUE OCT 22 2013 ...FOGGY MORNING TRANSITIONS TO A SOGGY EVENING AS A COLD FRONT APPROACHES... .UPDATE... MOIST AIRMASS AHEAD OF AN APPROACHING COLD FRONT PRODUCED PATCHES OF DENSE FOG FOR PORTIONS OF THE EASTERN TAMPA BAY AREA THIS MORNING...WITH AREAS OF FOG OVER MUCH OF WEST CENTRAL AND SOUTHWEST FLORIDA THIS MORNING. AS THE DAYTIME HEATING CONTINUES...EXPECT THE FOG TO IMPROVE AND THE LOW STRATUS CLOUDS TO LIFT. ALLOWED DENSE FOG ADVISORY TO EXPIRE AT 10 AM...AND ISSUED UPDATED ZONES TO REMOVE MENTIONS OF FOG. OTHERWISE...06Z MAV GUIDANCE IS TRENDING TOWARDS THE RAINS AHEAD OF THE FRONT ARRIVING FASTER AND AFFECTING THE TAMPA BAY AREA SOUTHWARD SOONER. HAVE UPDATED THE FORECAST TO SHOW THESE ELEVATED RAIN CHANCES. LINE OF RAIN CAN BE SEEN ON RADAR IN THE GULF ABOUT TO ENTER THE TBW OUTER WATERS AND 07Z HRRR GUIDANCE SHOWS THE POTENTIAL FOR A LINE OF SHOWERS FROM TAMPA BAY NORTHWARD LATE AFTERNOON INTO THE EARLY EVENING. RAISED POPS AFTER 00Z AS WELL...TO ACCOUNT FOR THE INCREASING CHANCE OF SOME RAIN OVERNIGHT AS THE MAIN LINE MOVES THROUGH. WILL CONTINUE TO KEEP AN EYE ON THESE TRENDS FOR THE NEXT FORECAST PACKAGE ISSUANCE LATER THIS AFTERNOON. && .AVIATION... IFR/LIFR CIGS AND VSBYS AT KLAL AND MVFR VSBYS AT KTPA WILL ERODE AWAY BY 15Z THIS MORNING WITH VFR EXPECTED AT ALL TERMINAL SITES THE REMAINDER OF TODAY WITH AN INCREASE IN MID AND HIGH LEVEL CLOUDS DURING THE AFTERNOON WITH SOME VCSH FROM KSRQ NORTH TO KTPA...KPIE AND KLAL AFTER 22Z. CIGS AND VSBY WILL BEGIN TO LOWER TONIGHT WITH CLOUDS THICKEN AND RAIN CHANCES INCREASE ACROSS THE REGION AHEAD OF COLD FRONT...WITH MVFR CIGS DEVELOPING AT ALL SITES AFTER 23/09Z. LIGHT AND VARIABLE WINDS WILL BECOME SOUTHWEST TO WEST AROUND 10 KNOTS AFTER 15Z. && .MARINE... LINE OF RAIN MOVING INTO THE WATERS IN THE NEXT FEW HOURS. EXPECT CONDITIONS TO DETERIORATE THROUGHOUT THE DAY. NO MAJOR CHANGES TO THE FORECAST...EXPECTING STRONGER WINDS AND WAVES BEHIND THE FRONT THAT COULD REACH CAUTIONARY...AND POSSIBLY ADVISORY...CRITERIA. && .PRELIMINARY POINT TEMPS/POPS... TPA 86 74 84 63 / 50 70 40 10 FMY 89 75 87 68 / 30 60 60 40 GIF 89 72 84 62 / 50 60 40 10 SRQ 86 73 85 64 / 40 70 50 20 BKV 86 71 83 54 / 60 70 30 10 SPG 86 76 84 69 / 50 70 40 10 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...NONE. GULF WATERS...NONE. && $$ UPDATE/MARINE...02/GARCIA AVIATION...57/MCMICHAEL
AREA FORECAST DISCUSSION
NWS MIAMI FL
958 AM EDT TUE OCT 22 2013 .UPDATE... THE MORNING SURFACE ANALYSIS SHOWED A FRONTAL BOUNDARY EXTENDING WSW FROM CENTRAL FLORIDA TO THE SOUTHWEST GULF OF MEXICO AND A WEAK RIDGE AXIS EXTENDING WWD ACROSS THE BAHAMAS. OBSERVATIONS AROUND THE LOCAL AREA SHOWED LIGHT SSE WINDS AROUND THIS RIDGE AXIS WITH DEWPOINTS IN THE MID 70S. ALTHOUGH THERE WERE SOME SMALL PATCHES OF FOG AROUND AND JUST BEFORE DAYBREAK...THE LATEST SATELLITE IMAGERY INDICATED THOSE AREAS HAVE BURNED OFF WITH MOSTLY CLEAR SKIES. THE MORNING SOUNDING AT MIA SHOWED SSE LOW- LEVEL WINDS VEERING TO THE SW ABOVE 850 MB AND A PWAT OF 1.75". THE LATEST RUC ANALYSIS LINES UP WELL WITH THE CURRENT SYNOPTIC PATTERN AND GENERALLY INDICATES THE DEEP LAYER MOISTURE INCREASING THROUGH THE DAY AS AN UPPER TROUGH AND FRONTAL BOUNDARY APPROACH THE AREA. THE LATEST WRF/HRRR MODEL SOLUTIONS INDICATE MAINLY SCATTERED SEA BREEZE DRIVEN SHOWERS/TSTMS INITIATING 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. THE CURRENT FORECAST PACKAGE REMAINS ON TRACK WITH NO MAJOR UPDATES NECESSARY AT THIS TIME. 85/AG && .PREV DISCUSSION... /ISSUED 751 AM EDT TUE OCT 22 2013/ AVIATION... TERMINAL KAPF COULD EXPERIENCE BRIEF PERIODS OF MINOR VISIBILITY RESTRICTIONS AND SCT002 IN THE EARLY MORNING HOURS DUE TO FOG/LOW STRATUS. BY 12Z- 13Z THE FOG/STRATUS SHOULD DISSIPATE BUT REMAINING VFR. THUNDERSTORM ACTIVITY THIS AFTERNOON IS EXPECTED TO BE ISOLATED AND MAINLY IN THE VICINITY OF TERMINAL KPBI BUT VCTS NOT ASSIGNED WITH COVERAGE EXPECTED TO BE LOW. BD/KOB PREV DISCUSSION... /ISSUED 400 AM EDT TUE OCT 22 2013/ DISCUSSION... SHOWERS AND THUNDERSTORMS FROM LAST EVENING HAVE DISSIPATED AND GIVEN WAY TO MOSTLY CLEAR SKIES ACROSS THE AREA. DUE TO THE WET GROUND AND A DIFFUSE BOUNDARY DRAPED ACROSS THE CENTRAL FLORIDA PENINSULA...AREAS OF FOG WILL BE POSSIBLE THIS MORNING MAINLY ACROSS INTERIOR AREAS. MOISTURE RICH SOUTHWEST FLOW WILL CONTINUE THROUGH THE DAY WITH CHANCES FOR AFTERNOON SHOWERS AND A FEW THUNDERSTORMS AGAIN MAINLY ACROSS THE INTERIOR. HUMIDITY LEVELS WILL ALSO INCREASE AS A RESULT WITH PWAT VALUES APPROACHING 2 INCHES. THE FORECAST FOCUS WILL THEN TURN TO THE APPROACHING COLD FRONT THAT IS EXPECTED TO ENTER THE AREA WEDNESDAY AFTERNOON. AS THE FRONT PUSHES THROUGH...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG THE BOUNDARY. WITH PWATS NEARING 2.25 INCHES BY WEDNESDAY EVENING...THE MAIN THREAT AT THIS TIME WITH ANY STORMS WILL BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL WEDNESDAY AFTERNOON AND EVENING. AS THE FRONT CLEARS THE AREA LATE WEDNESDAY NIGHT...MODELS STILL INDICATE DEEP MOISTURE OVERRUNNING THE BOUNDARY WITH CONTINUED SOUTHWEST FLOW ALOFT THROUGH THURSDAY. THIS WILL KEEP RAINFALL CHANCES THROUGH THURSDAY WITH BETTER CHANCES TO THE SOUTH. MODELS THEN STAY 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. MARINE... LIGHT SOUTH-SOUTHWEST WINDS WILL CONTINUE THROUGH 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. AVIATION... MAINLY VFR CONDITIONS ARE EXPECTED FOR ALL SOUTH FLORIDA TERMINALS EARLY THIS MORNING. THERE COULD BE SOME PATCHY FOG OR AREAS OF FOG EARLY THIS MORNING...BUT MAINLY EXPECTED IN THE INTERIOR REGIONS. BUT WILL AMEND AS NECESSARY. LIGHT SOUTHEASTERLY FLOW PREVAILS ACROSS THE REGION BUT COULD BE LIGHT AND VARIABLE AT THE TERMINALS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 88 72 87 73 / 30 30 50 30 FORT LAUDERDALE 87 76 87 74 / 20 20 50 40 MIAMI 88 75 87 75 / 20 20 50 40 NAPLES 88 73 87 71 / 20 30 50 40 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS WICHITA KS
712 AM CDT TUE OCT 22 2013 .UPDATE... ISSUED AT 712 AM CDT TUE OCT 22 2013 THIS MORNING: THE PURPOSE FOR THE UPDATE IS TWO-FOLD: 1) TO REMOVE SPRINKLES FROM PARTS OF CENTRAL & SOUTH-CENTRAL KS. 2) TO ADJUST CLOUD COVER TO REFLECT SATELLITE TRENDS TO FOCUS CLOUD COVER OVER SE KS THIS MORNING. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 333 AM CDT TUE OCT 22 2013 TODAY: ADDED A FEW SPRINKLES THIS MORNING BASED ON RADAR/SURFACE OBSERVATIONS...WITH RUC SHOWING TRANSIENT LIFT MOISTURE TRACKING ACROSS EASTERN EDGE OF FORECAST AREA EARLY THIS MORNING. OTHERWISE IT IS A CHALLENGING TEMPERATURE FORECAST WITH A LOT RIDING ON WIND DIRECTION AND CLOUDS. RELATIVELY DRY AIRMASS AND POSSIBLE DOWNSLOPE FLOW COULD REALLY BOOST TEMPERATURES THIS AFTERNOON. GIVEN SLIGHT COOL BIAS YESTERDAY AND WHAT SHOULD BE FAIRLY GOOD BREAKS IN CLOUDS LATER...WILL HEDGE A COUPLE DEGREES WARMER TODAY AND HOPEFULLY MINIMIZE ERROR EITHER WAY. TONIGHT: RIDGE AXIS WILL SETTLE OVER AREA WITH A SHARP FALL IN TEMPERATURES EARLY. SOME RETURN FLOW/CLOUDS MAY DEVELOP AFTER MIDNIGHT ACROSS WESTERN SECTIONS. HOWEVER CONDITIONS APPEAR FAVORABLE FOR WIDESPREAD FROST OVER FLINT HILLS/SOUTHEAST KS WHERE WINDS WILL LIKELY REMAIN NEAR CALM ALL NIGHT. WILL HOIST HEADLINES FOR FROST ADVISORY IN MOST LIKELY AREAS AND LET DAY SHIFT ADJUST WESTWARD IF NEEDED. WED-THU: QUICK WARM-UP SHOULD COMMENCE ON WED WITH GOOD WARMING JUST AHEAD OF NEXT FRONT THAT TRAVERSE MOST OF THE AREA DURING THE DAY. TEMPERATURES WILL LIKELY FALL IN THE AFTERNOON ACROSS NORTHERN HALF OF THE AREA AND WILL HAVE NON DIURNAL TEMPERATURES IN GRIDS. TOUGH CALL ON TEMPERATURES WED NIGHT WITH WIND INITIALLY...BUT WITH RIDGING BUILDING INTO AREA...MAY SEE TEMPERATURES TUMBLE TOWARDS DAYBREAK...MOST LIKELY IN SOUTHEAST KS. COLD AIR ADVECTION CONTINUES ON THU WITH MAXES 10-15 DEGREE COOLER THAN WED. LACK OF MOISTURE SHOULD PRECLUDE ANY MENTION OF PRECIPITATION. -HOWERTON .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 333 AM CDT TUE OCT 22 2013 MEDIUM RANGE MODELS STILL IN FAIRLY GOOD AGREEMENT GIVEN THE TYPICAL ISSUES OF TIMING SHORTWAVES IN NORTHWEST FLOW. RETURN FLOW ON FRI...WITH COLD FRONT MOVING THROUGH ON SAT. RETURN FLOW DEVELOPS SUN NIGHT AND PERSISTS INTO MON. SOME DIFFERENCES IN TIMING OF FRONT...BUT SMALL CHANCES CERTAINLY JUSTIFIED ON MON ACROSS SE KS. GIVEN RETURN OF CLOUDS AND INFLUX OF MOISTURE...HAVE BUMPED UP LOWS FOR MON. DIURNAL RANGE MAY BE EVEN MORE LIMITED ON MON IN SE KS WHERE LOW CLOUDS AND PRECIPITATION COULD PERSIST MOST OF THE DAY. -HOWERTON && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 712 AM CDT TUE OCT 22 2013 EXCEPT FOR NW WINDS THAT WILL INCREASE TO 15-20KTS ~18Z ALL AREAS TO SHOULD GOOD WEATHER WITH CLOUDINESS LIMITED TO ~8,000FT ALTOCU. THE NW WINDS WILL QUICKLY DIMINISH EARLY THIS EVENING AS THEY SHIFT SLOWLY TO THE N. && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 68 39 71 38 / 0 0 0 0 HUTCHINSON 67 38 69 37 / 0 0 0 0 NEWTON 65 38 69 36 / 0 0 0 0 ELDORADO 66 35 69 36 / 10 0 0 0 WINFIELD-KWLD 68 37 73 38 / 0 0 0 0 RUSSELL 66 37 67 34 / 0 0 0 0 GREAT BEND 66 37 68 34 / 0 0 0 0 SALINA 66 36 69 36 / 0 0 0 0 MCPHERSON 66 37 69 36 / 0 0 0 0 COFFEYVILLE 68 36 69 38 / 10 0 0 0 CHANUTE 67 33 65 35 / 10 0 10 0 IOLA 65 32 65 35 / 10 0 10 0 PARSONS-KPPF 67 33 67 34 / 10 0 0 0 && .ICT WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY FROM 1 AM TO 9 AM CDT WEDNESDAY FOR KSZ052-053- 069>072-094>096-099-100. && $$ ES
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
747 AM EDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT TUE OCT 22 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE INTO THE WRN CONUS AND A BROAD DOWNSTREAM TROUGH OVER THE CNTRL AND ERN CONUS. A MID LEVEL LOW JUST NORTH OF THE SAULT WAS LIFTING SLOWLY TO THE ENE. AT THE SFC...LOW PRES WAS LOCATED A THE SRN END OF JAMES BAY WITH A TROUGH EXTENDING TO THE SW THROUGH ERN LAKE SUPERIOR INTO ERN UPPER MI. AFTER A BRIEF PERIOD OF MODERATE TO HEAVY SNOW ASSOCIATED WITH LOW LEVEL CONV AHEAD OF THE TROUGH...WIND PARALLEL SNOW BANDS HAVE DEVELOPED BUT WITH LESS ORGANIZED CONVECTIVE ELEMENTS. SNOWFALL AMOUNTS WERE IN THE 1 TO 3 INCH RANGE OVER THE WEST DURING THE EVENING BUT HAVE ONLY AMOUNTED TO LESS THAN INCH OVER N CNTRL UPPER MI NEAR NEGAUNEE. WITH LOW LEVEL TEMPS NEAR FREEZING AND MILD AIR MOVING IN FROM THE RELATIVELY WARM LAKE SUPERIOR...WATER TEMPS IN THE UPPER 40S...WET BULB ZERO HEIGHTS HAVE REMAINED HIGH ENOUGH FOR THE SNOW TO CHANGE BACK TO MAINLY RAIN OVER THE KEWEENAW AND ALONG LAKE SUPERIOR TO THE EAST. TODAY...EXPECT THE LAKE ENHANCED SNOW BANDS TO CONTINUE AS CAA DROPS 850 MB TEMPS FROM AROUND -7C TO NEAR -9C. HOWEVER...WITH DRIER AIR MOVING INTO THE REGION AND LOWER INVERSION HEIGHTS IN THE PRESENCE OF SYNOPTIC SCALE SUBSIDENCE BEHIND THE DEPARTING MID LEVEL LOW...THE SNOW SHOWER INTENSITY/COVERAGE WILL DIMINISH THIS MORNING LEAVING JUST SCT LIGHT SNOW/RAIN SHOWERS BY AFTERNOON. TONIGHT...THE MODELS SUGGEST A WEAK SHORTWAVE TROUGH MAY SLIDE INTO THE AREA. WITH 850 MB TEMPS REMAINING NEAR -8C...AN INCREASE IN 850-700 MB MOISTURE...AND MORE FAVORABLE LOW LEVEL CONV AS LAND BREEZES DEVELOP...SNOW SHOWERS ARE EXPECTED TO INCREASE FOR LOCATIONS FAVORED TY NW TO WNW FLOW. HOWEVER...GIVEN THE MARGINAL INSTABILITY...ANY ACCUMULATIONS ARE EXPECTED TO REMAIN AT AN INCH OR LESS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 350 AM EDT TUE OCT 22 2013 THE UPPER GREAT LAKES WILL STILL BE UNDER THE WESTERN SIDE OF THE UPPER TROUGH AT THE START OF THE LONG TERM PERIOD...WHICH WILL REMAIN IN PLACE THROUGH THURSDAY NIGHT. AT THE SURFACE...A LOW WILL BE LOCATED TO THE EAST OF JAMES BAY AND HIGH PRESSURE WILL BE SLIDING SOUTHEAST THROUGH THE NORTHERN PLAINS THROUGH THURSDAY. THIS WILL ALLOW NORTHWEST FLOW TO BE PERSISTENT ON WEDNESDAY AND THURSDAY. 850MB TEMPS DURING THIS PERIOD LOOK TO BE HOVERING RIGHT AROUND -7 TO -8C AND WITH LAKE SUPERIOR TEMPS ON AVERAGE AROUND 8-9C...THERE IS PLENTY OF OVER LAKE INSTABILITY TO SUPPORT LAKE EFFECT SHOWERS. ON WEDNESDAY MORNING...EXPECT THE WINDS TO BE NW TO WNW...BEFORE A WEAK SURFACE TROUGH AND SHORTWAVE SWEEPS THROUGH WEDNESDAY EVENING AND SHIFTS THE DIRECTION TO A MORE NORTH-NORTHWESTERLY DIRECTION. WILL HAVE THE HIGHEST POPS EAST OF GRAND MARAIS OVER THE EAST AND ALONG ALL OF THE HIGHER TERRAIN OVER THE WEST FOR WEDNESDAY...THEN SHIFTING TO MORE TRADITIONAL NW-NNW FLOW LOCATIONS FOR WEDNESDAY NIGHT (EG ALGER COUNTY OVER THE EAST). WILL CONTINUE TO SHOW DEFINITE POPS FOR THE FAVORED EASTERN CWA LOCATIONS SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS IDEA FOR THE LAST COUPLE OF DAYS. WILL CONTINUE THE HIGH POPS FOR THURSDAY...ALTHOUGH TEMPS MAY WARM A DEGREE. EVEN WITH THE LIKELY/DEFINITE POPS FOR WEDNESDAY...DON/T EXPECT THE INTENSITY TO BE AS STRONG AS LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT WHEN A QUICK PERIOD OF DEEPER MOISTURE WITH THE SHORTWAVE AND SURFACE TROUGH MOVES THROUGH. DEEP CLOUD LAYER (10-12KFT) AND LAKE INDUCED CAPE VALUES OF 300-500 J/KG SUPPORT THE POTENTIAL FOR STRONGER LAKE EFFECT SNOW BANDS ON WEDNESDAY NIGHT. THIS COULD EVEN END UP PRODUCING MODERATE TO HEAVY SNOWFALL IN QUICK BURSTS...SIMILAR TO WHAT WAS SEEN IN PORTIONS OF WESTERN UPPER MICHIGAN THIS AFTERNOON/EVENING (JACOBSVILLE SAW 2.6IN IN 1HR). THE MAIN LIMITING FACTORS FOR THIS EVENT WILL BE THE LOWER SNOW RATIOS AND MID-UPPER 30S NEAR SURFACE TEMPERATURES. CONTINUE TO THINK SNOW RATIOS WILL BE ON THE LOW END FOR TRADITIONAL LAKE EFFECT EVENTS...SINCE THE CLOUD LAYER WILL BE AT OR BELOW THE DGZ. THUS...WITH MUCH OF THE FORCING BELOW...WOULD EXPECT RATIOS TO BE IN THE 10-13 TO 1 RANGE INSTEAD OF THE NORMAL 17-25 TO 1. IN ADDITION...WITH UPPER 40 DEGREE WATER MODIFYING THE NEAR SURFACE AIR...LOCATIONS NEAR LAKE SUPERIOR WILL BE HOVERING IN THE MID TO EVEN UPPER 30S. THIS WILL TRY TO PUSH WETBULB ZERO VALUES UP TO 1KFT...WHICH WOULD BE ENOUGH FOR SOME MIXING OF RAIN/SNOW NEAR THE SHORELINE. IN ADDITION...THOSE WARMER SURFACE TEMPERATURES WILL ATTEMPT TO LIMIT THE SNOWFALL ACCUMULATION EXCEPT UNDER THE STRONGER BANDS...WHERE THE RATE WILL COMPENSATE FOR THE WARMER TEMPS. THEREFORE...PINNING DOWN SNOWFALL AMOUNTS WITH THE MULTIPLE FACTORS IS TRICKY FOR THIS EARLY SEASON EVENT. IN GENERAL...THINK THE SNOWFALL AMOUNTS DURING THE WEDNESDAY AFTERNOON/NIGHT PERIOD WILL BE UNDER ADVISORY CRITERIA (GENERALLY 1-3INCH) WITH SOME LOCATIONS SEEING ADVISORY AMOUNTS (3-4INCH) WHERE ANY STRONGER BANDS SETS UP. ONE OTHER ITEM TO MENTION FOR THE WEDNESDAY AFTERNOON AND NIGHT PERIOD IS THE POTENTIAL FOR SOME WATERSPOUTS OVER THE SOUTHEASTERN PART OF LAKE SUPERIOR. WITH THE CONVECTIVE CLOUD DEPTH OF 10-12KFT AND DELTA-T VALUES AROUND 16...THAT DOES PLACE THAT AREA ON THE EDGE OF THE WATERSPOUT POTENTIAL ON THE SZILAGYI WATERSPOUT NOMOGRAM. THUS...WILL PUT IN A SLIGHT CHANCE MENTION IN THAT AREA AND THEN END IN BY THURSDAY MORNING SINCE THE MOISTURE DEPTH BEGINS TO LESSEN. THE UPPER TROUGH WILL FINALLY BEGIN SHIFTING EAST ON THURSDAY NIGHT AND A HIGH PRESSURE RIDGE WILL BEGIN TO MOVE EAST INTO THE UPPER GREAT LAKES. THIS WILL BRING DRIER AIR INTO THE CWA FROM WEST TO EAST WHILE BACKING THE WINDS TO THE SOUTHWEST. THUS...EXPECT THE ONGOING LAKE EFFECT PRECIPITATION TO DIMINISH OVER THE WEST AND THEN SLOWLY DIMINISH AND SHIFT EAST OVER THE EASTERN CWA. FORTUNATELY...THE MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH THE SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE WEST AND SLIDING SOUTHEAST INTO THE UPPER GREAT LAKES REGION ON FRIDAY NIGHT INTO SATURDAY. THIS CLIPPER SYSTEM (WITH THE LOW SLIDING ALONG THE EASTERN SHORE OF LAKE SUPERIOR) SHOULD PRODUCE SOME PRECIPITATION OVER THE CWA ON FRIDAY NIGHT AND HAVE THE HIGHEST POPS OVER THE NORTHEAST HALF. THEN AFTER THE COLD FRONT MOVES THROUGH...EXPECT THERE TO BE A PERIOD OF LAKE ENHANCED RAIN/SNOW IN THE NORTHWEST WIND FAVORED LOCATIONS AS 850MB TEMPS FALL BACK TO -6C. WILL HIGHLIGHT THE HIGHEST POPS IN THOSE LOCATIONS FOR SATURDAY AND THEN GRADUALLY DIMINISH THEM SATURDAY NIGHT INTO SUNDAY...AS THE UPPER TROUGH SHIFTS EAST AND HIGH PRESSURE MOVES OVER THE CWA. IT LOOKS LIKE THE SUNDAY INTO SUNDAY NIGHT PERIOD WILL GIVE A LITTLE BIT OF A REPRIVE TO THE UNSETTLED WEATHER THAT WE WILL SEE THIS WEEK. LATEST TRENDS IN THE 00Z MODEL RUNS HAVE THE UPPER TROUGH THAT WILL BE DIGGING OVER THE ROCKIES POTENTIALLY BECOMING CUTOFF OVER THE WEST COAST. AS THIS OCCURS ON MONDAY...AN ELONGATED TROUGH ASSOCIATED FROM A LOW IN THE CENTRAL PLAINS WILL SLOWLY MOVE EAST ACROSS THE AREA. THIS WILL BE SOMETHING TO KEEP AN EYE ON...AS TEMPERATURES WILL LIKELY BE COLD ENOUGH FOR SNOW ALOFT (ALTHOUGH SURFACE TEMPERATURES ARE MARGINAL) AND IT COULD PRODUCE MEASURABLE SNOW. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 746 AM EDT TUE OCT 22 2013 EXPECT MVFR WX TO DOMINATE MOST OF THIS FCST PERIOD WITH COLD NW FLOW BETWEEN A DEPARTING LOW PRESSURE TROOUGH AND AN INCOMING RIDGE. THE CLOSER APPROACH OF THE SFC RIDGE AND WEAKER PRES GRADIENT LATER TODAY WILL ALLOW GUSTY NW WINDS TO DIMINISH. AT SAW LAKE EFFECT SNOW SHOWERS WILL DIMINISH EARLY TODAY AND THEN VFR WX WILL RETURN THIS AFTERNOON AS THE RIDGE APPROACHES WHILE LAKE MOISTURE KEEPS MVFR CIGS AT CMX/IWD WITH PREVAILING NW WINDS. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT TUE OCT 22 2013 NORTH TO NORTHWEST GALES THIS MORNING ARE EXPECTED TO DIMINISH BY AFTERNOON AS THE GRADIENT WEAKENS BEHIND A DEPARTING TROUGH. HOWEVER...WITH PERSISTENT LOW PRES TO THE EAST AND RIDGE OVER THE NORTHERN PLAINS...WINDS WILL BE LINGER IN THE 20 TO 30KT RANGE THROUGH THE THU. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... WINTER WEATHER ADVISORY UNTIL 8 AM EDT THIS MORNING FOR MIZ005. LAKE SUPERIOR... GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LSZ264>267. GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ263. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...JLB MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
713 AM EDT TUE OCT 22 2013 .AVIATION... //DISCUSSION... DRY WESTERLY FLOW SCOURED OUT EVEN THE LAKE EFFECT STRATOCU FROM LAKE MICHIGAN BEFORE SUNRISE LEAVING CLEAR CONDITIONS TO START THE DAY. SUNSHINE AND SURFACE HEATING WILL THEN HELP CLOUDS REDEVELOP DURING THE LATE MORNING WITH A VFR CEILING BACK IN PLACE FOR THE AFTERNOON. A FAST MOVING LOW PRESSURE SYSTEM WILL ARRIVE FROM THE CENTRAL PLAINS OVER INDIANA AND OHIO BY LATE AFTERNOON THROUGH THIS EVENING. THIS SYSTEM COULD PRODUCE LIGHT RAIN IN THE DTW TERMINAL CORRIDOR THROUGH LATE EVENING BUT NO RESTRICTION IS EXPECTED OTHER THAN A CEILING BELOW 5000 FEET. BACKING LOW LEVEL FLOW AFTER MIDNIGHT WILL THEN HELP STRATOCU DIMINISH AGAIN TOWARD SUNRISE WEDNESDAY OVER ALL TERMINAL SITES. //DTW THRESHOLD THREATS... * MEDIUM CONFIDENCE IN CEILING BELOW 5000 FEET AFTER 15Z TUESDAY WITH HIGHER CONFIDENCE AFTER 00Z. && .PREV DISCUSSION...ISSUED 347 AM EDT TUE OCT 22 2013 SHORT TERM... TODAY AND TONIGHT CONFLUENT FLOW ALOFT THROUGH THE SOUTH FLANK OF THE UPPER LOW WILL MAINTAIN THE MID LEVEL DRY SLOT OVER THE SOUTHERN GREAT LAKES FOR MOST OF TODAY. THIS WILL KEEP THE INFLUENCE OF LAKE MICHIGAN SUBDUED ON THIS SIDE OF THE STATE, ESPECIALLY IN TERMS OF PRECIPITATION AND POSSIBLY EVEN CAUSING A DISRUPTION IN THE CLOUD FIELD. TRENDS IN LOW LEVEL RH PROFILES IN THE NAM AND RAP MODELS INDICATE DRY AIR FROM THE MIDWEST AS LOW AS 850 MB DURING THE MORNING WHICH COULD LEAD TO SOME BREAKS IN THE LAKE CLOUD PATTERN OR A TENDENCY FOR THE CLOUDS TO HUG CLOSER TO THE SHORELINE OVER SW LOWER EARLY IN THE DAY. THE LATEST SATELLITE IMAGERY SUPPORTS A GENERAL PARTLY SUNNY START TO THE DAY AND ALLOWS FOR SOME RENEWED STRATOCU FORMATION DUE TO SURFACE HEATING AND BEFORE HIGH CLOUDS INCREASE WITH THE NEXT SHORT WAVE LATE IN THE DAY. THE BREAKS OF SUNSHINE WILL HELP MAX TEMPS RECOVER INTO THE MID AND UPPER 40S. THE NEXT SHORT WAVE WILL ARRIVE OVER INDIANA FROM THE CENTRAL PLAINS BY EVENING NEARLY IN PHASE WITH THE SECONDARY SURFACE TROUGH SLIDING THROUGH THE NORTHERN GREAT LAKES. THE SURFACE TROUGH WILL MOVE THROUGH SE MICHIGAN DURING THE LATE AFTERNOON AND EVENING WHILE THE SHORT WAVE APPROACHES THE SOUTHERN MICHIGAN BORDER. THE COMBINATION OF THESE TWO FEATURES WILL GIVE INSTABILITY OVER LAKE MICHIGAN A CHANCE TO PERK UP, ALONG WITH BOUNDARY LAYER INSTABILITY DUE TO SURFACE HEATING, FOR A CHANCE OF LIGHT RAIN SHOWERS DURING THE LATE AFTERNOON. THE BEST CHANCE OF RAIN WILL BE DURING THE EVENING GENERALLY SOUTH OF THE I-69 CORRIDOR WHERE THE NORTH FLANK OF THE SHORT WAVE FORCING WILL INTERACT WITH THE SURFACE TROUGH. THIS REFLECTS A SOUTHWARD MODEL ADJUSTMENT ON TRACK OF SHORT WAVE WITH THE MID LEVEL TROWAL AXIS REMAINING SOUTH OF THE STATE LINE. MODEL DEPICTIONS OF DCVA ARE TOO WEAK TO GO WITH ANYTHING GREATER THAN A CHANCE POP BEFORE THE SYSTEM EXITS EASTWARD AFTER MIDNIGHT. MOST OF THE OVERNIGHT HOURS WILL THEN BE DOMINATED BY RENEWED LOW LEVEL COLD ADVECTION ON NW FLOW. BOTH THICKNESS FIELDS AND MODEL SOUNDINGS INDICATE PRECIPITATION POTENTIAL ENDED BY THE TIME THE BOUNDARY LAYER COOLS ENOUGH FOR SNOW, AND AS NORTHWEST FLOW CONFINES LAKE EFFECT CLOSER TO LAKE MICHIGAN. MIN TEMPS NEAR THE FREEZING MARK LOOK ON TARGET BY SUNRISE WEDNESDAY. LONG TERM... LONGWAVE TROUGHING ANCHORED BY A LARGE CLOSED LOW OVER THE GREAT LAKES WILL MAINTAIN MOIST CYCLONIC FLOW OVER THE AREA UNTIL THE DEPARTURE OF THE LOW TO THE NORTHEAST LATE IN THE WEEK. IN THE MEANTIME, NORTHWEST GRADIENT FLOW AROUND THE EASTERN FLANK OF HIGH PRESSURE BUILDING INTO THE CENTRAL CONUS WILL KEEP DAYTIME HIGHS IN THE MID TO UPPER 40S BENEATH H85 TEMPS PROGGED TO HOVER AROUND -5C. IN GENERAL, NORTHWEST FLOW WILL MINIMIZE CONCERN FOR LAKE EFFECT SHOWERS TO ADVANCE INTO THE AREA AS CONVECTIVE PLUMES OFF OF LAKE MICHIGAN WILL TEND TO BE SHUNTED TO OUR SOUTHWEST. THE EXCEPTION WILL BE WEDNESDAY WHEN THE LOW LEVEL FLOW IS PROGGED TO BACK TOWARD WESTERLY AHEAD OF AN APPROACHING SHORTWAVE. WITH THE HELP OF DIURNAL HEATING, A DEEP CONVECTIVE BOUNDARY LAYER WITH ORIGINS OVER LAKE MICHIGAN STANDS A DECENT CHANCE OF ADVECTING EAST INTO THE AREA. CHANCE POPS THEREFORE REMAIN IN PLACE FOR WED AFTERNOON, WITH THE BEST CHANCE FOR SHOWERS SOUTH OF I-69. LOW-LEVEL FLOW WILL BACK TO A LESSER DEGREE ON WED NIGHT AS A SHEARED H5 PV ANOMALY TRACKS ACROSS THE MI/OH BORDER. DYNAMIC FORCING ASSOCIATED WITH THE WAVE ITSELF WARRANTS CHANCE POPS NEAR THE OHIO BORDER, BUT POTENTIAL WILL BE LIMITED WITH THE DEEPER MOISTURE CONFINED TO THE OHIO VALLEY. MOIST CYCLONIC FLOW IN ADDITION TO CONTRIBUTIONS FROM LAKE SUPERIOR/MICHIGAN WILL ENSURE A SUBSTANTIAL BOUNDARY LAYER CONTRIBUTION TO A MOSTLY CLOUDY SKY CONDITION THAT IS FORECAST TO PERSIST THROUGH AT LEAST THURSDAY NIGHT. INHERITED FORECAST LOWS NEAR 30 FOR MOST AREAS STILL LOOK REASONABLE, BUT ANY POTENTIAL FOR CLEARING WILL BE WORTH MONITORING AS A FEW HOURS OF GOOD RADIATING WITHIN THE RESIDENT AIRMASS WOULD SEND TEMPS WELL INTO THE 20S. SHORTWAVE RIDGING IN ADVANCE OF ANOTHER HIGH-LATITUDE WAVE WILL WORK INTO THE AREA ON FRIDAY AGAINST A BACKDROP OF LARGER SCALE HEIGHT RISES OWING TO EASTWARD PROGRESSION OF THE LONGWAVE TROUGH. HIGH PRESSURE WILL BUILD INTO THE AREA AS A RESULT AND SHOULD HELP BREAK UP BOUNDARY LAYER CLOUD COVER TO SOME EXTENT, BUT HIGHS WILL AGAIN REMAIN IN THE 40S WITH THE THERMAL TROUGH PROGGED TO MAINTAIN ITS GRIP ON THE AREA. MARINE... A SECONDARY SURGE OF COLD AIR SPREADING OVER THE GREAT LAKES TODAY WILL REQUIRE GALE WARNINGS TO CONTINUE OVER NORTHERN AND CENTRAL LAKE HURON. WARNINGS HAVE BEEN ADDED FOR SAGINAW BAY AS FREQUENT GUSTS TO 35 KNOTS ARE NOW EXPECTED THERE AS THE WIND FUNNELS DOWN THE CENTER OF THE BAY. SMALL CRAFT ADVISORIES WILL HOLD ALONG THE SOUTHERN LAKE HURON NEARSHORE AREAS. THE STRONG WIND WILL KEEP WATERSPOUT POTENTIAL LOW EVEN AS INSTABILITY INCREASES OVER THE WATER TODAY WITH A BETTER CHANCE OVER THE OPEN WATERS OF LAKE HURON TONIGHT AS THE WIND DIMINISHES. WIND SPEED WILL CONTINUE TO DIMINISH TUESDAY NIGHT INTO WEDNESDAY BUT WILL REMAIN FROM THE NORTHWEST AND WEST, MAINTAINING BELOW NORMAL TEMPERATURE THROUGH THE END OF THE WEEK. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ421-LHZ422...UNTIL 8 PM TUESDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...FROM 8 PM TUESDAY TO 8 AM WEDNESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT SANILAC...UNTIL 8 AM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....BT SHORT TERM...BT LONG TERM....JVC MARINE.......BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
611 AM CDT TUE OCT 22 2013 .UPDATE... ISSUED AT 611 AM CDT TUE OCT 22 2013 UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 315 AM CDT TUE OCT 22 2013 LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW THE UPPER LOW WHICH BROUGHT MUCH COLDER TEMPERATURES TO THE AREA BEING SHUNTED INTO EASTERN ONTARIO AS A FEW REINFORCING SHORTWAVES DROP SOUTHEAST THROUGH CENTRAL CANADA INTO THE HIGH PLAINS. THE MAIN SHORTWAVE OF INTEREST FOR THE SHORT TERM CAN BE SEEN OVER EASTERN SOUTH DAKOTA... AND IS HELPING TO GENERATE THE LIGHT PCPN SEEN ON RADAR AND SURFACE OBS OVER FAR SOUTHWEST MINNESOTA... EASTERN SOUTH DAKOTA... AND NORTHERN IOWA. MOST OF THIS ACTIVITY LOOKS LIKE IT WILL REMAIN SOUTH OF OUR AREA THIS MORNING... SO MAINLY JUST MENTIONED SOME FLURRIES OR LOW POPS WITH NO SNOWFALL ACCUMULATIONS. OTHERWISE... TODAY LOOKS BENIGN ACROSS THE FORECAST AREA... WITH SOME PEAKS OF SUN INTERSPERSED WITH LINGERING STRATOCU. WE MAINTAIN SOMEWHAT OF A 925-850MB THERMAL TROUGH OVER THE AREA TODAY... WHICH SHOULD KEEP PLENTY OF CLOUDS IN PLACE... AND LATEST 11-3.9 MICRON IMAGERY SHOWS PLENTY OF CLOUDS TO THE NORTH DROPPING SOUTH WITH TIME. HOWEVER... THERE ARE INDICATIONS THAT THE BOUNDARY LAYER FLOW WILL BECOME MORE ANTICYCLONIC THIS AFTERNOON... WHICH COULD WORK TO GENERATE SOME DECENT BREAKS IN THE CLOUD COVER. PLAYED THINGS MORE PESSIMISTICALLY FOR NOW GIVEN SATELLITE TRENDS AND FORECAST PROFILES... AND WENT WITH MOSTLY CLOUDY SKIES FOR MUCH OF THE DAY INTO TONIGHT. THE NEXT SHORTWAVE OF INTEREST WILL TAKE A VERY SIMILAR TRACK AS THIS MORNING/S... AND LOOKS TO DROP BY TO OUR SOUTHWEST VERY LATE TONIGHT INTO WEDNESDAY. AT THIS POINT... IT LOOKS LIKE ANY CHANCE FOR PCPN WILL ONCE AGAIN BE CONFINED TO THE FAR SOUTHWEST/SOUTH... AND WILL MAINLY BE ON WEDNESDAY. HOWEVER... DID INCLUDE SOME LOW POPS OVER THE SOUTHWEST FOR VERY LATE TONIGHT AS SOME ISENTROPIC LIFT AND FRONTOGENESIS START TO IMPINGE ON THE AREA. DID NOT MAKE ANY SUBSTANTIVE CHANGES TO THE GOING TEMPERATURE FORECASTS... WHICH WILL ONCE AGAIN BE QUITE A BIT BELOW NORMAL. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 315 AM CDT TUE OCT 22 2013 EARLY MORNING WATER VAPOR IMAGERY WITH 500MB HEIGHTS AND WINDS IDENTIFIED THE BROAD UPPER LEVEL RIDGE ORIENTED ALONG THE WEST COAST OF NORTH AMERICA...WITH A DEEP TROUGH OVER THE GREAT LAKES REGION. THE PV ANOMALY ASSOCIATED WITH THIS VORT MAX WILL DEVELOP A CYCLONE ALONG THE EASTERN SHORE OF JAMES BAY...AND ANOMALOUSLY COLD AIR WILL CONTINUE TO BE DRIVEN SOUTH ACROSS THE UPPER MIDWEST FOR THE NEXT COUPLE OF DAYS. MEANWHILE A TROPICAL PLUME OF MOISTURE ORIGINATING OVER SOUTHERN MEXICO WAS STREAMING NORTHEASTWARD ACROSS THE EASTERN SEABOARD. BY THURSDAY THIS SUBTROPICAL JET WILL PHASE WITH THE NORTHERN STREAM TROUGH AND BOMB OUT A SUB 960MB SURFACE CYCLONE OFF THE COAST OF NEW FOUNDLAND. THIS POWERFUL CYCLONE WILL CAUSE THE NORTHERLY WINDS CURRENTLY IN PLACE ACROSS THE REGION TO BECOME MORE WESTERLY BY THE END OF THE WEEK. FARTHER UPSTREAM SUBSIDENCE WILL LEAD LEE SIDE WARMING ON THE FOOTHILLS OF THE ROCKIES...AND THIS WARM AIR WILL MOVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY BY FRIDAY. IN FACT...THE 22.00 GEM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT THE SATURDAY 00Z RAB AT MSP SHOULD MEASURE ABOVE 0C AT H850. NOT EXACTLY A HEAT WAVE...BUT SLIGHTLY MORE MILD NONE THE LESS. THIS WARM UP WILL BE SHORT LIVED AS ANOTHER SHORTWAVE DRIVING THIS LOW LEVEL WARM AIR ADVECTION WILL CAUSE A CYCLONE TO TRACK ACROSS SOUTHERN CANADA...AND DRIVE A WEAK COLD FRONT THROUGH THE REGION. THIS FRONTAL BOUNDARY WILL EVENTUALLY BECOME ORIENTED EAST/WEST...AND SET THE STAGE FOR A POTENTIALLY SIGNIFICANT STORM SYSTEM TO DEVELOP NEXT WEEK OVER THE MIDWEST. IN SUMMARY...A FEW WEAK WAVED EMBEDDED IN NORTHWEST FLOW WILL KEEP MID LEVEL CLOUDS IN TACT FOR MOST OF THIS WEEK...BUT NOTHING TO MERIT HAVING ANY POPS IN THE FORECAST. TEMPERATURES WILL MODERATE SLIGHTLY BY THE WEEKEND...BUT SHOULD STILL REMAIN BELOW CLIMATOLOGY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 611 AM CDT TUE OCT 22 2013 MAIN AVIATION CONCERN IS STRATOCU ATTEMPTING TO SLIDE SOUTH INTO THE AREA... WHICH IS CURRENTLY PRODUCING WIDESPREAD MVFR CEILINGS. THE SHORTWAVE TO OUR SOUTHWEST IS PRODUCING SOME LIGHT PCPN... BUT IT WILL STAY SOUTH OF TAF SITES... WITH SOME VFR CEILINGS BEING THE ONLY THING IT SHOULD PRODUCE. CURRENT THINKING IS THAT THE MVFR CEILINGS WILL DROP SOUTH ACROSS ALL BUT KRWF... BUT WILL THEN START TO RISE THROUGH THE DAY... AND PROBABLY SCATTER OUT DURING THE EVENING HOURS. HOWEVER... THERE IS A FAIR DEGREE OF UNCERTAINLY ON HOW STUBBORN THE CLOUDS WILL BE... AND THERE/S A CHANCE FOR SOME DECENT BREAKS TODAY BUT ALSO FOR THINGS TO STICK AROUND LONGER TONIGHT. KMSP...MAIN CONCERN IS WITH CEILINGS DROPPING IN FROM THE NORTH. IT APPEARS THEY WILL PRODUCE MVFR CONDITIONS FOR A GOOD PART OF THE DAY... BUT WILL BE ABOVE 017 SO IMPACTS SHOULD BE MINIMAL. THE SCATTERING OUT ADVERTISED FOR TONIGHT COULD EASILY OCCUR SOONER OR LATER BY SEVERAL HOURS WITH MUCH DEPENDING UPON HOW MUCH RESIDUAL MOISTURE WINDS UP TRAPPED BENEATH A SUBSIDENCE INVERSION AND AT WHAT LEVEL THAT INVERSION MANIFESTS. /OUTLOOK FOR KMSP/ WEDNESDAY AFTERNOON THROUGH THURSDAY...VFR. NORTHWEST WIND AROUND 10KT. THURSDAY NIGHT...VFR. NORTHWEST WIND AROUND 10 KT BECOMING WEST. FRIDAY...VFR. WEST WIND 5 TO 10 KT BECOMING SOUTHWEST 15 TO 20 KT. FRIDAY NIGHT...MVFR CEILINGS POSSIBLE LATE. SOUTHWEST WIND 10 TO 20 KT BECOMING WEST. SATURDAY...MVFR CEILINGS POSSIBLE EARLY. NORTHWEST WIND 15 TO 20 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ UPDATE... SHORT TERM... LONG TERM...JRB AVIATION...
AREA FORECAST DISCUSSION
NWS HASTINGS NE
620 AM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 425 AM CDT TUE OCT 22 2013 MAIN FORECAST CONCERNS WILL BE LIGHT SHOWERS OR SPRINKLES THIS MORNING AND TEMPERATURES. CURRENT RADAR TRENDS SHOW THAT THE SPRINKLES OR LIGHT SHOWERS HAVE MOVED INTO THE SOUTHEAST HALF OR SO OF THE FORECAST AREA EARLY THIS MORNING. SATELLITE SHOWS A FEW BREAKS IN THE CLOUDS...BUT MOSTLY CLOUDY SKIES WILL PERSIST. THE CLOUD COVER HAS HELPED TO KEEP TEMPERATURES A LITTLE ON THE WARMER SIDE. MODELS HAVE HAD SOME LIGHT SHOWERS OR SPRINKLES MOVING THROUGH THE FORECAST AREA DURING THE MORNING. THE NAM AND GFS INDICATE THAT THESE WILL CONTINUE INTO THE MORNING AND BE GONE BY MID DAY...BUT THE HRRR AND 4KM WRF ARE A LITTLE QUICKER TO MOVE THINGS THROUGH THE AREA AND INDICATE THAT THE PRECIPITATION COULD BE DONE AS EARLY AS BY SUN RISE THIS MORNING. WITH THE CURRENT LOCATION OF THE SPRINKLES ON THE RADAR AM INCLINED TO BELIEVE THE SHORT TERM MODELS AND BRING AN EARLY END TO THE PRECIPITATION. BASED ON THE MOVEMENT OF THE PRECIPITATION...THE RETURNS ON THE RADAR AND PRECIPITATION AMOUNTS AS IT MOVES OVER EXPECT THAT SPRINKLES WILL BE THE EXTENT OF THE PRECIPITATION. THE SURFACE PRESSURE GRADIENT TIGHTENS FOR A WHILE THIS MORNING AND THE WINDS AT 850MB ARE 25 TO 35 KTS DURING THE MORNING AND INTO THE AFTERNOON HOURS. EXPECT THERE TO BE BREEZY CONDITIONS DURING THE LATE MORNING INTO EARLY AFTERNOON BEFORE WINDS DIMINISH AS THE SUN GOES DOWN THIS AFTERNOON. CLOUDS WILL BE MORE PREVALENT IN THE NORTHEAST PART OF THE FORECAST AREA AND WILL KEEP TEMPERATURES ON THE LOWER SIDE WHILE A LITTLE MORE SUN AND WARMER TEMPERATURES ALOFT WILL ALLOW FOR SOME WARMER TEMPERATURES IN THE SOUTHWEST. SOME CLOUD COVER WILL CONTINUE ACROSS THE AREA THROUGH THE NIGHT TONIGHT...BUT DESPITE THE CLOUDS TEMPERATURES ACROSS THE AREA WILL BE COOLER THAN TONIGHT AS THE WIND DIMINISHES AND A FEW BREAKS IN THE CLOUDS MOVE THROUGH. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 425 AM CDT TUE OCT 22 2013 BIGGEST CHALLENGE WILL BE DETERMINING TEMPERATURES. THE LONG TERM MODELS CONTINUE TO FORECAST NORTHWEST FLOW AT THE BEGINNING OF THE LONG TERM FORECAST AS WE WILL BE SITUATED BETWEEN A BROAD SYNOPTIC LONGWAVE TROUGH TO THE EAST AND A RIDGE ALONG THE WEST COAST...WITH AN EMBEDDED CUTOFF LOW OFF THE SOUTHERN CALIFORNIA COAST. THE UPPER LEVEL PATTERN WILL BE HIGHLY AMPLIFIED TO BEGIN THE LONG TERM. THERE COULD BE JUST ENOUGH INFLUENCE LEFT FROM A SHORTWAVE TROUGH FORECAST TO GIVE US A SHOT AT SOME LIGHT PRECIPITATION IN OUR FAR NORTHEAST AS THE SHORTWAVE TROUGH DEPARTS TO THE SOUTHEAST. THIS SEEMS TO BE A NEAR COPY OF WHAT HAS HAPPENED OVERNIGHT AND INTO THIS MORNING...EXCEPT ENERGY WILL BE A BIT FARTHER TO THE EAST...LESSENING OUR CHANCES OF MUCH PRECIPITATION AND HAVE KEPT IT OUT OF THE FORECAST...ANTICIPATING THAT ANY PRECIPITATION WILL BE JUST TO THE EAST. MODELS INDICATE CONSIDERABLE HEIGHT RISES BEHIND THE COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED WAVE AND I HAVE INCREASED WIND SPEEDS ACCORDINGLY. FOR THE MOST PART...I KEPT HIGH TEMPERATURES CLOSE TO PREVIOUS FORECASTS. I HAVE LOWERED TEMPERATURES A FEW DEGREES FOR WEDNESDAY NIGHT AS SKY COVER SHOULD BE RELATIVELY SCANT AND WIND SPEEDS SLACKEN. THIS COULD BE THE FIRST HARD FREEZE FOR MANY AREAS OF THE CWA. ALSO...THURSDAY NIGHT COULD BE TRICKY FOR LOW TEMPERATURES AS RETURN FLOW COULD CAUSE TEMPERATURES TO STEADY OUT OR EVEN RISE BY OVERNIGHT...ESPECIALLY SOUTHWEST. IN FACT...OUR SOUTHWEST MAY NOT COOL THAT MUCH AT ALL AS WARM AIR ADVECTION TAKES OVER THERE FIRST. AS A RESULT...LOW TEMPERATURES HAVE BEEN RAISED IN OUR FAR SOUTHWEST TO THE MID 30S TO NEAR 40...WHILE CENTRAL AND EASTERN AREAS WILL HAVE LOWS IN THE MID TO UPPER 20S...AND AGAIN...WITH TEMPERATURES BECOME STEADY OR SLOWLY RISING BY THE OVERNIGHT HOURS. TEMPERATURES WILL BE RATHER SEASONABLE FOR THE MOST PART FOR THE REST OF THE LONG TERM. FRIDAY NIGHT LOOKS LIKE THE WARMEST BEFORE ANOTHER COOL SHOT OF AIR COMES IN WITH ANOTHER WAVE. PATTERN STILL SHOULD BECOME MORE QUASI-ZONAL BY SUNDAY...AS MODELS HAVE BEEN ADVERTISING FOR AWHILE. THIS IS A RESULT OF A MORE SIGNIFICANT SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST. THERE COULD BE A NOTICEABLE WARM-UP IN ADVANCE OF THIS WAVE...BUT I AM GETTING MIXED SIGNALS FROM OPERATION AND ENSEMBLE PREDICTIONS AND I FIND IT BEST TO STICK WITH THE INITIAL ALLBLEND GRIDS. THE FORECAST ESSENTIALLY STAYS DRY THROUGH MONDAY AS TIMING OF THIS WAVE STILL KEEPS IT FAR ENOUGH AWAY TO BRING IN MUCH PRECIPITATION TO OUR AREA AND A COLD FRONT SHOULD BE FAR ENOUGH EAST TO KEEP ANYTHING THAT DEVELOPS ALONG IT TO OUR EAST. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 620 AM CDT TUE OCT 22 2013 VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD WITH MAINLY MID LEVEL CLOUDS IN AND OUT. WINDS ARE EXPECTED TO INCREASE DURING THE DAY WITH THE STRONGEST WINDS LATE THIS MORNING INTO EARLY THIS AFTERNOON. BY EVENING THE WINDS WILL START TO DIMINISH. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...HEINLEIN AVIATION...JCB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1026 AM CDT TUE OCT 22 2013 .UPDATE... ISSUED AT 952 AM CDT TUE OCT 22 2013 UPDATE FOR MINOR ADJUSTMENTS TO POPS THIS AFTERNOON AND TONIGHT. HAVE DELAYED LIGHT RAIN IN THE FAR NORTHWEST UNTIL LATE AFTERNOON. THE BULK OF THE PRECIPITATION IS EXPECTED AFTER 00Z THIS EVENING. THE FAR SOUTHWEST SHOULD BE WARM ENOUGH IN THE LOW LEVELS TO REMAIN MOSTLY RAIN...WHILE A SWATH OF LIGHT SNOW IS EXPECTED MAINLY EAST OF HIGHWAY 22. ACCUMULATIONS SHOULD BE UNDER AN INCH. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 309 AM CDT TUE OCT 22 2013 MAIN CONCERN IN THE SHORT TERM FORECAST PERIOD WILL BE MORE PRECIPITATION CHANCES LATER THIS AFTERNOON / TONIGHT. EARLY MORNING RADAR MOSAIC SHOWED LIGHT RETURNS MOVING ACROSS SOUTH CENTRAL NORTH DAKOTA. THE OVERALL TREND HAS BEEN FOR THE AREA OF PRECIPITATION TO DIMINISH OVER THE PAST COUPLE HOURS AND THIS IS IN LINE WITH MOST SHORT TERM MODEL SOLUTIONS. THE NEXT UPPER WAVE ARRIVES LATER THIS AFTERNOON / TONIGHT. THE NAM / GFS SUGGEST THE STRONGER FORCING WILL NOT ARRIVE UNTIL AFTER 18Z AND WILL DELAY POPS ACCORDINGLY. THE PRECIPITATION CHANCES SHOULD SPREAD FROM NORTHWEST TO SOUTHEAST IN CONCERT WITH THE BEST FORCING / VERTICAL MOTION...AND THIS TREND IS ALREADY WELL COVERED IN THE POP GRIDS. THERMAL PROFILES AGAIN SUGGEST EITHER RAIN OR SNOW WILL BE THE MAIN PRECIPITATION TYPES. SIMILAR TO MONDAY...HAVE USED 35F AS THE ALL SNOW THRESHOLD TRANSITIONING TO RAIN AT 38F. SNOW AMOUNTS WILL GENERALLY STAY LESS THAN HALF AN INCH. LOOKING AT TEMPERATURES...HAVE KEPT HIGHS FOR TODAY WELL BELOW NORMAL AGAIN. WILL GO WITH MID 30S TO NEAR 40 EAST...TO MID 40S TO LOW 50S WEST. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 309 AM CDT TUE OCT 22 2013 THE PERSISTENT NORTHWEST FLOW ALOFT INDUCED BY AN UPPER RIDGE ACROSS THE ROCKIES AND A LONGWAVE TROUGH IN SOUTHEAST CANADA AND INTO THE GREAT LAKES/OHIO VALLEY WILL LIFT NORTHEAST THROUGH THE PERIOD. THIS WILL SHIFT THE MAIN JET AND PROLONGED PERIOD OF UPPER SHORTWAVES FURTHER EAST THURSDAY THROUGH SATURDAY. WARM AIR ADVECTION WILL INCREASE FRIDAY AND SATURDAY...AHEAD OF THE NEXT ALBERTA CLIPPER WHICH IS SLATED FOR SUNDAY AFTERNOON INTO MONDAY. MUCH COLDER TEMPERATURES BEHIND THE CLIPPER ARE FORECAST FOR MONDAY AND TUESDAY. FOR WEDNESDAY...A SHORTWAVE WILL SLIDE SOUTHEAST ACROSS THE TURTLE MOUNTAINS AND INTO THE JAMES RIVER VALLEY BY AFTERNOON. A CHANCE FOR MAINLY SNOW SHOWERS IN THE MORNING AND A RAIN/SNOW MIX POSSIBLE IN THE AFTERNOON IN THE FAR SOUTH AS THE WAVE DEPARTS. COLD H85 AIR IN THE TURTLE MOUNTAINS AND ACROSS EAST CENTRAL NORTH DAKOTA MAY YIELD FLURRIES OR A SNOW SHOWER WEDNESDAY AFTERNOON. FOR THURSDAY THROUGH SATURDAY...NORTHWEST FLOW RELAXES AS THE STRONGEST HEIGHT GRADIENT SHIFTS EAST. A BRIEF TRANSITION TO WARM AIR ADVECTION COMMENCES FRIDAY AND MAINTAINS A PRESENCE INTO SUNDAY. WILL MAINTAIN A DRY FORECAST DURING THIS TIME WITH A MODERATING TREND FRIDAY AS HIGHS WILL RISE INTO THE 50S MOST AREAS EXCEPT IN THE TURTLE MOUNTAINS. EXPECT HIGHS IN THE 40S TO LOWER 50S SATURDAY AND SUNDAY. FOR SUNDAY AFTERNOON THROUGH MONDAY...A POTENT ALBERTA CLIPPER WILL MAKE ITS WAY INTO WESTERN/CENTRAL NORTH DAKOTA. H85 TEMPS TAKE A DIGGER FROM AROUND +8C SUNDAY AFTERNOON TO -10C MONDAY AFTERNOON. UNCERTAINTY AT THIS TIME REVOLVES AROUND PRECIPITATION TOTALS. BOTH THE GFS AND ECMWF ADVERTISE MOSTLY POST FRONTAL PRECIPITATION/SNOW. THE DIFFERENCE IS THAT THE ECMWF IS MORE AGGRESSIVE IN AMOUNTS AND IS SLOWEST TO MOVE THROUGH...WHILE THE GFS IS QUICKEST AND LESS ROBUST. AT THIS TIME...JUST LOOKING AT SNOWFALL AMOUNTS THE GFS WOULD PROBABLY NOT WARRANT WINTER WEATHER HEADLINES BUT THE ECMWF WOULD. CONSIDERING OVERALL IMPACTS...ENOUGH EVIDENCE IN BOTH MODELS FOR A WINTER HEADLINE. WILL TAKE A SLOW APPROACH AND BEGIN TO ADVERTISE THIS SYSTEM IN THE HAZARDOUS WEATHER OUTLOOK. WILL MONITOR AND ADJUST IN THE COMING DAYS AS THE LONG RANGE MODELS COME INTO BETTER AGREEMENT. TUESDAY LOOKS DRY BUT REMAINS COLD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 615 AM CDT TUE OCT 22 2013 A WIDE VARIETY OF CONDITIONS EXIST EARLY THIS MORNING ACROSS WESTERN AND CENTRAL NORTH DAKOTA. EVERYTHING FROM IFR TO VFR IS BEING REPORTED. IT APPEARS THE IFR CONDITIONS ARE TIED TO A FRONTAL BOUNDARY LOCATED FROM NORTHWEST NORTH DAKOTA INTO CENTRAL SOUTH DAKOTA. THE LATEST HRRR SUGGESTS A MAJORITY OF THE IFR CONDITIONS SHOULD NOT MOVE MUCH THIS MORNING BEFORE A GRADUAL IMPROVING TREND TAKES HOLD. WILL STAY WITH MVFR OR VFR THIS MORNING...AND SHOW SOME IMPROVEMENT INTO THE AFTERNOON. ANOTHER CHANCE OF PRECIPITATION ARRIVES THIS AFTERNOON NEAR KISN...THEN SPREADS SOUTHEAST TONIGHT. WILL TREND TO MVFR AGAIN AS THE PRECIPITATION SPREADS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...RP KINNEY SHORT TERM...CK LONG TERM...KS AVIATION...CK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
615 AM CDT TUE OCT 22 2013 .UPDATE... ISSUED AT 615 AM CDT TUE OCT 22 2013 LATEST FOG/STRATUS SHOWS IFR/MVFR CIGS WITH PATCHY FOG ACROSS WESTERN AND CENTRAL NORTH DAKOTA. STATIONARY FRONTAL SYSTEM STRETCHED FROM NEAR MOOSE JAW CANADA...TO TIOGA AND GLEN ULLIN AND INTO PIERRE SOUTH DAKOTA. VERY WEAK RADAR RETURNS SHOWING UP NEAR AND ALONG THIS CONVERGENCE ZONE. THE CURRENT FORECAST HAS THIS HANDLED WELL AND ONLY MINOR UPDATES TO HOURLY SENSIBLE WEATHER ELEMENTS. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 309 AM CDT TUE OCT 22 2013 MAIN CONCERN IN THE SHORT TERM FORECAST PERIOD WILL BE MORE PRECIPITATION CHANCES LATER THIS AFTERNOON / TONIGHT. EARLY MORNING RADAR MOSAIC SHOWED LIGHT RETURNS MOVING ACROSS SOUTH CENTRAL NORTH DAKOTA. THE OVERALL TREND HAS BEEN FOR THE AREA OF PRECIPITATION TO DIMINISH OVER THE PAST COUPLE HOURS AND THIS IS IN LINE WITH MOST SHORT TERM MODEL SOLUTIONS. THE NEXT UPPER WAVE ARRIVES LATER THIS AFTERNOON / TONIGHT. THE NAM / GFS SUGGEST THE STRONGER FORCING WILL NOT ARRIVE UNTIL AFTER 18Z AND WILL DELAY POPS ACCORDINGLY. THE PRECIPITATION CHANCES SHOULD SPREAD FROM NORTHWEST TO SOUTHEAST IN CONCERT WITH THE BEST FORCING / VERTICAL MOTION...AND THIS TREND IS ALREADY WELL COVERED IN THE POP GRIDS. THERMAL PROFILES AGAIN SUGGEST EITHER RAIN OR SNOW WILL BE THE MAIN PRECIPITATION TYPES. SIMILAR TO MONDAY...HAVE USED 35F AS THE ALL SNOW THRESHOLD TRANSITIONING TO RAIN AT 38F. SNOW AMOUNTS WILL GENERALLY STAY LESS THAN HALF AN INCH. LOOKING AT TEMPERATURES...HAVE KEPT HIGHS FOR TODAY WELL BELOW NORMAL AGAIN. WILL GO WITH MID 30S TO NEAR 40 EAST...TO MID 40S TO LOW 50S WEST. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 309 AM CDT TUE OCT 22 2013 THE PERSISTENT NORTHWEST FLOW ALOFT INDUCED BY AN UPPER RIDGE ACROSS THE ROCKIES AND A LONGWAVE TROUGH IN SOUTHEAST CANADA AND INTO THE GREAT LAKES/OHIO VALLEY WILL LIFT NORTHEAST THROUGH THE PERIOD. THIS WILL SHIFT THE MAIN JET AND PROLONGED PERIOD OF UPPER SHORTWAVES FURTHER EAST THURSDAY THROUGH SATURDAY. WARM AIR ADVECTION WILL INCREASE FRIDAY AND SATURDAY...AHEAD OF THE NEXT ALBERTA CLIPPER WHICH IS SLATED FOR SUNDAY AFTERNOON INTO MONDAY. MUCH COLDER TEMPERATURES BEHIND THE CLIPPER ARE FORECAST FOR MONDAY AND TUESDAY. FOR WEDNESDAY...A SHORTWAVE WILL SLIDE SOUTHEAST ACROSS THE TURTLE MOUNTAINS AND INTO THE JAMES RIVER VALLEY BY AFTERNOON. A CHANCE FOR MAINLY SNOW SHOWERS IN THE MORNING AND A RAIN/SNOW MIX POSSIBLE IN THE AFTERNOON IN THE FAR SOUTH AS THE WAVE DEPARTS. COLD H85 AIR IN THE TURTLE MOUNTAINS AND ACROSS EAST CENTRAL NORTH DAKOTA MAY YIELD FLURRIES OR A SNOW SHOWER WEDNESDAY AFTERNOON. FOR THURSDAY THROUGH SATURDAY...NORTHWEST FLOW RELAXES AS THE STRONGEST HEIGHT GRADIENT SHIFTS EAST. A BRIEF TRANSITION TO WARM AIR ADVECTION COMMENCES FRIDAY AND MAINTAINS A PRESENCE INTO SUNDAY. WILL MAINTAIN A DRY FORECAST DURING THIS TIME WITH A MODERATING TREND FRIDAY AS HIGHS WILL RISE INTO THE 50S MOST AREAS EXCEPT IN THE TURTLE MOUNTAINS. EXPECT HIGHS IN THE 40S TO LOWER 50S SATURDAY AND SUNDAY. FOR SUNDAY AFTERNOON THROUGH MONDAY...A POTENT ALBERTA CLIPPER WILL MAKE ITS WAY INTO WESTERN/CENTRAL NORTH DAKOTA. H85 TEMPS TAKE A DIGGER FROM AROUND +8C SUNDAY AFTERNOON TO -10C MONDAY AFTERNOON. UNCERTAINTY AT THIS TIME REVOLVES AROUND PRECIPITATION TOTALS. BOTH THE GFS AND ECMWF ADVERTISE MOSTLY POST FRONTAL PRECIPITATION/SNOW. THE DIFFERENCE IS THAT THE ECMWF IS MORE AGGRESSIVE IN AMOUNTS AND IS SLOWEST TO MOVE THROUGH...WHILE THE GFS IS QUICKEST AND LESS ROBUST. AT THIS TIME...JUST LOOKING AT SNOWFALL AMOUNTS THE GFS WOULD PROBABLY NOT WARRANT WINTER WEATHER HEADLINES BUT THE ECMWF WOULD. CONSIDERING OVERALL IMPACTS...ENOUGH EVIDENCE IN BOTH MODELS FOR A WINTER HEADLINE. WILL TAKE A SLOW APPROACH AND BEGIN TO ADVERTISE THIS SYSTEM IN THE HAZARDOUS WEATHER OUTLOOK. WILL MONITOR AND ADJUST IN THE COMING DAYS AS THE LONG RANGE MODELS COME INTO BETTER AGREEMENT. TUESDAY LOOKS DRY BUT REMAINS COLD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 615 AM CDT TUE OCT 22 2013 A WIDE VARIETY OF CONDITIONS EXIST EARLY THIS MORNING ACROSS WESTERN AND CENTRAL NORTH DAKOTA. EVERYTHING FROM IFR TO VFR IS BEING REPORTED. IT APPEARS THE IFR CONDITIONS ARE TIED TO A FRONTAL BOUNDARY LOCATED FROM NORTHWEST NORTH DAKOTA INTO CENTRAL SOUTH DAKOTA. THE LATEST HRRR SUGGESTS A MAJORITY OF THE IFR CONDITIONS SHOULD NOT MOVE MUCH THIS MORNING BEFORE A GRADUAL IMPROVING TREND TAKES HOLD. WILL STAY WITH MVFR OR VFR THIS MORNING...AND SHOW SOME IMPROVEMENT INTO THE AFTERNOON. ANOTHER CHANCE OF PRECIPITATION ARRIVES THIS AFTERNOON NEAR KISN...THEN SPREADS SOUTHEAST TONIGHT. WILL TREND TO MVFR AGAIN AS THE PRECIPITATION SPREADS ACROSS WESTERN AND CENTRAL NORTH DAKOTA. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...CK LONG TERM...KS AVIATION...CK
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
618 AM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 422 AM CDT TUE OCT 22 2013 CLIPPER SYSTEM MOVING ACROSS THE AREA THIS MORNING. LOOKS LIKE ENOUGH UPPER LEVEL ENERGY HANGS AROUND TO KEEP THE PRECIPITATION GOING A BIT LONGER THIS MORNING THAN PREVIOUSLY FORECAST. NAM...HRRR AND RAP ALL SUGGEST LIGHT PRECIPITATION WILL LINGER THROUGH 15Z IN SIOUX FALLS AND 17Z OR SO ACROSS PORTIONS OF NORTHWEST IOWA. WOULD EXPECT THIS TO BE PREDOMINATELY LIGHT SNOW ALONG AND NORTHEAST OF A HURON TO SIOUX FALLS TO SPENCER IOWA LINE...WITH A FEW SNOWFLAKES EVEN POTENTIALLY MIXING IN AS FAR SOUTH AS AREAS JUST NORTH OF THE MISSOURI RIVER. THE AFTERNOON HOURS WILL BE DRY...WITH SKIES BECOMING PARTLY SUNNY. EXPECTING GOOD MIXING AGAIN...AND BASED ON HOW WARM WE WERE ABLE TO GET YESTERDAY...WENT AHEAD AND BUMPED HIGHS UP A FEW DEGREES FOR TODAY...MAINLY LOW AND MID 40S. ANOTHER CLIPPER SYSTEM WILL DROP SOUTHEAST TOWARDS THE AREA LATER TONIGHT INTO WEDNESDAY. TEMPERATURES TONIGHT ARE TRICKY. WITH CALM WINDS LOCATIONS IN THE EAST SHOULD DROP RAPIDLY IN THE EVENING HOURS. MEANWHILE AS CLOUDS INCREASE FROM WEST TO EAST TEMPERATURES WILL BEGIN TO RISE. TRIED TO SHOW THIS IN THE GRIDS...BUT WOULD NOT BE SURPRISED IF LOCATIONS EATS OF INTERSTATE 29 END UP A BIT COLDER THAN CURRENTLY FORECAST. THE CLIPPER SYSTEM ITSELF SEEMS TO BE TRENDING SOUTHWEST. FOLLOWING A CONSENSUS OF THE NAM...GFS...ECMWF AND HI RES MODELS SEEMS LIKE A GOOD CALL AT THIS POINT. OVERALL WOULD THINK THE OVERALL EVOLUTION WILL BE SIMILAR TO WHAT HAPPENED WITH THE CURRENT SYSTEM...A BROAD AREA OF LIGHT PRECIP AND A EMBEDDED BAND OF HIGHER QPF ASSOCIATED WITH MID LEVEL FRONTOGENESIS. 500 TO 300 MB Q VECTOR CONVERGENCE A BIT STRONGER WITH THE SYSTEM TONIGHT...LIKELY OWING TO A STRONGER UPPER JET. SO WOULD NOT BE SURPRISED IF QPF AMOUNTS END UP A BIT HIGHER OVERALL. PRECIPITATION TYPE IS AGAIN AN ISSUE. LOOKS PRETTY SIMILAR TO THIS MORNINGS EVENT IN THAT AN AREA OF SNOW WILL BE LIKELY ON THE NORTHERN EDGE OF THE BAND. BOUNDARY LAYER IS A BIT WARMER...SUGGESTING THE AREA THAT SEES MAINLY SNOW WILL PROBABLY BE PRETTY SMALL. AGAIN ONLY THINKING WE SEE A COATING TO AN INCH OF ACCUMULATION. WOULD THINK ANYWHERE ALONG AND NORTHEAST OF A HURON TO SIOUX FALLS TO SIOUX CITY LINE WOULD SEE THE BEST CHANCE OF THIS LIGHT ACCUMULATION. WILL CONTINUE TO MONITOR TRENDS...AS IF THINGS WORKS OUT JUST RIGHT...COULD SEE A NARROW AREA OF 1 TO 2 INCHES OF SNOW...BUT GIVEN THE MARGINAL THERMAL PROFILE AND QPF PLACEMENT UNCERTAINTY...CONFIDENCE REMAINS LOW. STILL SOME TIMING DIFFERENCES AS WELL...BUT GENERALLY LOOKS LIKE THE PRECIP WILL ENTER OUR WEST AROUND 08Z AND APPROACH INTERSTATE 29 AROUND 11Z. PRECIP WILL EXIT BY LATE MORNING OR EARLY AFTERNOON. SKIES WILL REMAIN MOSTLY CLOUDY THROUGH THE AFTERNOON...WITH ANOTHER DAY OF HIGHS ONLY IN THE 40S. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 422 AM CDT TUE OCT 22 2013 LESS ACTIVE PATTERN RETURNS TO THE AREA WEDNESDAY NIGHT AS WAVE EXITS TO THE SOUTHEAST. STILL IN COOL NORTHWEST FLOW INTO THURSDAY...SO WELL BELOW NORMAL TEMPERATURES WILL STICK AROUND FOR ONE MORE DAY. ANTICIPATE FAIR AMOUNT OF HEATING-DRIVEN CUMULUS IN OUR NORTHEAST THURSDAY AFTERNOON BASED ON FORECAST SOUNDINGS...WITH SOME MODELS SQUEEZING OUT A FEW SPRINKLES. HAVE NOT INCLUDED ANY PRECIP MENTION AT THIS TIME...BUT EVEN IF THEY DO OCCUR...SHOULD BE SPOTTY AND VERY LIGHT. NORTHWEST WINDS BECOMING GUSTY WITH THE GOOD MIXING AS WELL... WITH BOTH CLOUDS AND WIND DIMINISHING IN THE EVENING AS SURFACE RIDGE PUSHES INTO THE CWA FROM THE WEST. TEMPERATURES WEDNESDAY NIGHT AND THURSDAY NIGHT LIKELY TO BE IN THE MID-UPPER 20S MOST AREAS...WITH HIGHS THURSDAY AGAIN IN THE 40S. LONGER RANGE FRIDAY THROUGH MONDAY FEATURES WESTERN CONUS RIDGE NUDGING EASTWARD THROUGH THE WEEKEND. STRONG WARMING ALOFT ON FRIDAY NOT LIKELY TO BE FULLY REALIZED AT THE SURFACE...THOUGH MOST AREAS SHOULD AT LEAST WARM BACK INTO THE 50S...WITH SOME LOWER 60S NOT OUT OF THE QUESTION IN OUR SOUTHWEST. UPPER WAVE DROPPING FROM CENTRAL CANADA INTO THE WESTERN GREAT LAKES FRIDAY NIGHT/SATURDAY WILL DRAG A COOL FRONT SOUTHEAST THROUGH THE NORTHERN PLAINS. MODELS NOW TRENDING BACK TOWARD HOLDING THE COLDEST OF AIR WITH THIS SYSTEM NORTHEAST OF OUR AREA...THOUGH WILL LIKELY STILL SEE HIGHS SATURDAY KNOCKED BACK A FEW DEGREES FROM FRIDAYS READINGS...UPPER 40S IN SOUTHWEST MINNESOTA TO MID 50S IN OUR SOUTHWEST. ANOTHER PUSH OF WARMER AIR ALOFT SHOULD HELP HIGHS SUNDAY CLIMB BACK INTO THE 50S TO MAYBE LOWER 60S. THIS AHEAD OF STRONGER WAVE SLATED TO AFFECT THE REGION EARLY NEXT WEEK. MODELS DIFFERING ON TIMING SLIGHTLY...WITH GFS FASTER/COOLER THAN ECMWF BY LATE MONDAY...THOUGH BOTH MODELS CURRENTLY HOLD OFF BETTER PRECIP CHANCE FOR MOST OF OUR AREA UNTIL MONDAY NIGHT. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 612 AM CDT TUE OCT 22 2013 AREA OF LIGHT RAIN AND SNOW WILL DISSIPATE AND EXIT THE AREA BY LATE MORNING. CIGS IN THE LIFR TO MVFR RANGE WILL SLOWLY LIFT THROUGH THE MORNING...AND SHOULD BECOME VFR BY MID TO LATE AFTERNOON. BRIEF VISIBILITY REDUCTIONS INTO THE 2SM TO 4SM RANGE WILL BE POSSIBLE IN SNOW THROUGH MID MORNING AS WELL. VFR CONDITIONS SHOULD PREVAIL MOST OF TONIGHT. HOWEVER...ANOTHER LOW PRESSURE SYSTEM WILL BRING A RETURN TO THE LIGHT RAIN OR SNOW THREAT LATE TONIGHT INTO WEDNESDAY MORNING. AGAIN WOULD EXPECT CIGS TO DROP WITH THIS FEATURE. FOR NOW KEPT THE TAFS MVFR AT KHON AND VFR AT KFSD AND KSUX GIVEN UNCERTAINTY OF TIMING AND PLACEMENT OF PRECIPITATION SHIELD. ALTHOUGH WOULD EXPECT CIGS TO LOWER INTO THE MVFR TO IFR RANGE AT SOME POINT LATE TONIGHT OR EARLY WEDNESDAY WHERE THE AREA OF PRECIPITATION MOVES ACROSS. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...JH AVIATION...CHENARD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
609 AM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT TUE OCT 22 2013 AT 3 AM...A BAND OF LIGHT RAIN AND SNOW EXTENDED FROM CENTRAL IOWA NORTHWEST TO SOUTHEAST SOUTH DAKOTA. THIS PRECIPITATION IS LOCATED IN AN AREA OF 900 TO 700 MB FRONTOGENESIS THAT HAS DEVELOP AHEAD OF A SHORT WAVE TROUGH LOCATED OVER EASTERN SOUTH DAKOTA. THE MESO MODELS SUGGEST THAT THIS FORCING ALONG WITH THE 280-290K ISENTROPIC LIFT WILL REMAIN JUST SOUTH AND WEST OF THE FORECAST AREA. IN ADDITION WITH THE 280-290K CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN 20 AND 50 MB...THERE MAY BE SOME SATURATION ISSUES IN NORTHEAST IOWA. RAP BUFKIT SOUNDINGS SHOW THAT THERE WILL BE A VERY BRIEF PERIOD WHERE THE OMEGA WILL INTERSECT THE DEDRITIC GROWTH ZONE...BUT ALSO AT THIS TIME THERE IS STILL QUITE A BIT OF DRY AIR BELOW 800 MB. IT DEFINITELY LOOKS BETTER AS ONE HEADS SOUTH TO WATERLOO IOWA. DUE TO THIS...KEPT A 20 TO 40 PERCENT CHANCE OF RAIN AND SNOW BORDERING THE DES MOINES AND DAVENPORT COUNTY WARNING AREAS BETWEEN 22.10Z AND 22.20Z. THESE TIMES WERE BASED ON THE MESO MODELS. LIQUID AMOUNTS WILL BE LESS THAN A TENTH OF AN INCH AND SNOW AMOUNTS WILL BE LESS THAN A HALF INCH SOUTH OF A ST ANSGAR IOWA TO PLATTEVILLE WISCONSIN. FOR THIS EVENING...THE MODELS CONTINUE TO SHOW STEEP /7 TO 7.5 C/KM/ SURFACE TO 700 MB LAPSE RATES ACROSS THE FORECAST AREA. THIS WILL LIKELY KEEP SOME MID CLOUDS ACROSS THE FORECAST AREA. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 340 AM CDT TUE OCT 22 2013 ON WEDNESDAY...THE 22.00Z MODELS SHOW THAT ANOTHER SHORT WAVE TROUGH WILL MOVE SOUTHEAST ACROSS WESTERN AND SOUTHERN IOWA. AS A RESULT...MUCH OF THE FRONTOGENETIC FORCING AND 280-290K ISENTROPIC LIFT STAY WELL WEST AND SOUTH OF THE FORECAST AREA. WITH NOT MUCH LIFT AND 280-290K CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN 30 AND 50 MB... TOOK OUT THE PRECIPITATION CHANCES OUT OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN. LIKE THE 21.12Z MODELS...THE 22.00Z MODELS ARE CONTINUING TO TREND THAT THAT THE WESTERN PERIPHERY OF THE LONG WAVE TROUGH OVER EASTERN CANADA WILL SHIFT A BIT FURTHER EAST AND THIS WILL SHIFT THE STORM TRACK INTO THE MINNESOTA ARROWHEAD AND EASTERN WISCONSIN. AS RESULT...IT DOES NOT LOOK LIKE WE WILL SEE ANOTHER SURGE OF COLD INTO THE REGION FOR THE WEEKEND. THIS WILL ALLOW TEMPERATURES TO WARM CLOSER TO NORMAL. IN ADDITION...PRECIPITATION CHANCES LOOK TO MAINLY TO OUR NORTH AND EAST. HOWEVER CANNOT COMPLETELY TAKE OUT THE PRECIPITATION CHANCES ACROSS NORTH CENTRAL WISCONSIN...SO KEPT A 20 PERCENT CHANCE OF RAIN AND SNOW IN TAYLOR COUNTY FOR FRIDAY NIGHT INTO SATURDAY. LOOKING AHEAD TO EARLY NEXT WEEK...THE MODELS ARE NOW SHOWING THAT THE WESTERN RIDGE WILL RETROGRADE WEST AND THAT A LONG WAVE TROUGH WILL DEVELOP OVER THE INTER MOUNTAIN REGION. AS THIS OCCURS... THE UPPER LEVEL WINDS WILL SHIFT TO THE WEST AND SOUTHWEST. THIS WILL ALLOW EVEN WARMER AIR AIR TO MOVE BACK INTO THE AREA. THIS COULD BE OUR FIRST TASTE OF INDIAN SUMMER. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING) ISSUED AT 608 AM CDT TUE OCT 22 2013 CLOUD SHIELD ASSOCIATED WITH THE AREA OF LOW PRESSURE OVER NEBRASKA HAS FOR THE MOST PART STAYED TO THE SOUTH OF BOTH TAF SITES. HIGHER LEVEL CLOUDS ARE MAKING SLOW EASTWARD PROGRESS AND ARE EXPECTED TO SPREAD ACROSS BOTH TAF SITES THROUGH THE MORNING. AS THE DAY PROGRESSES AND THE SURFACE LOW MOVES ACROSS IOWA TOWARD ILLINOIS...IT IS EXPECTED TO START PULLING DOWN THE LOW LEVEL MOISTURE IN PLACE OVER NORTHERN MINNESOTA AND WISCONSIN. THIS SHOULD INITIALLY RESULT IN VFR CEILINGS THIS AFTERNOON AND EVENTUALLY GOING TO MVFR DURING THE EVENING. SOMEWHAT CONCERNED THAT THE CEILINGS COULD GO MVFR THIS AFTERNOON AS THESE CURRENTLY RESIDE OVER NORTHERN WISCONSIN INTO CENTRAL MINNESOTA. HOWEVER...THINK THE MIXED LAYER WILL GET DEEP ENOUGH BEFORE THE MOISTURE ARRIVES TO MAKE THE INITIAL CEILINGS BE VFR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1035 AM MDT TUE OCT 22 2013 .UPDATE... && .SHORT TERM...ONGOING FORECASTS LOOK GOOD. BATCH OF MID LEVEL CLOUD OVER FAR NORTHEAST COLORADO MOVING SOUTHEAST. NEXT BATCH OVER EASTERN WYOMING AND WESTERN NEBRASKA ALSO HEADING SOUTHEAST...SHOULD BE CLIPPING THE NORTHEAST CORNER AROUND 18Z. OTHERWISE...MAINLY CLEAR SKIES TO PREVAIL THROUGH THE AFTERNOON AND EVENING. FORECAST SOUNDINGS AND THICKNESS PROGS SUGGEST HIGHS ACROSS PLAINS TO WARM INTO THE 60S. ONLY MINOR TWEAKS TO TEMPERATURE GRIDS AT THIS TIME. .AVIATION...CURRENT TAF TRENDS SEEM ON TRACK. LIGHT SOUTHEAST WINDS TO SHIFT TO THE NORTHEAST AROUND 19Z...THEN BACK TO SOUTHEAST AT 23Z. SLIGHT CHANCE OF AN ANTICYCLONE DEVELOPING NEAR THE DENVER AREA WHICH MAY KEEP WINDS SOUTHEAST THROUGH THE AFTERNOON...LATEST HRRR AND RAP SHOW THIS FEATURE FAIRLY WEAK. WILL MAINTAIN THE CURRENT TAF SOLUTION. VFR CONTINUES. && .PREV DISCUSSION... /ISSUED 403 AM MDT TUE OCT 22 2013/ SHORT TERM...CURRENT SATELLITE IMAGERY SHOWS MID LEVEL CLOUD DECK STILL HOLDING OVER THE NORTHEAST PLAINS. HOWEVER...THERE ARE SIGNS OF EROSION FROM THE NORTHWEST AS UPSTREAM CLOUD BAND EXTENDING INTO WYOMING WAS BEGINNING TO BREAK UP. AS A RESULT...EXPECT THE NEARLY OVERCAST SKIES OVER THE NORTHEASTERN PLAINS TO SEE A GRADUAL EROSION THROUGH THE MORNING HOURS LEAVING BEHIND MOSTLY SUNNY SKIES BY AFTERNOON. FROM THE FRONT RANGE URBAN CORRIDOR WESTWARD ACROSS THE MOUNTAINS...SKIES WILL BE MOSTLY SUNNY THROUGH THE ENTIRE DAY. WARM ADVECTION WAS UNDERWAY AND WE EXPECT ABOUT 4C WARMING FROM YESTERDAY. THIS ALONG WITH A WARMER START TO THE DAY WILL HELP PUSH HIGHS CLOSE TO 10 DEGREES F WARMER. TODAY WILL BE OUR FIRST DAY WITH AN ABOVE NORMAL HIGH SINCE OCT 13TH. FOR TONIGHT...MOSTLY CLEAR SKIES AND LIGHT WINDS SHOULD ALLOW FOR BETTER RADIATIONAL COOLING AND LOW TEMPS CLOSER TO NORMAL. LONG TERM...A VERY STABLE RIDGE/TROUGH UPPER AIR PATTERN WILL REMAIN IN POSITION OVER THE COUNTRY THROUGH THE END OF THE WEEK... LEAVING COLORADO HIGH AND DRY THROUGH THE FORECAST PERIOD. LIGHT TO MODERATE NORTHWESTERLY FLOW ALOFT WILL CONTINUE AS THE WESTERN U.S. UPPER RIDGE IS HELD IN PLACE BY A DEEP TROUGH OVER THE GREAT LAKES AND EASTERN CANADA. FOR WEDNESDAY AND THURSDAY... TEMPERATURES WILL BE AROUND SEASONAL NORMALS...BUT THEN WARMER TEMPERATURES ARE EXPECTED FOR THE WEEKEND. DRY CONDITIONS WILL PREVAIL ACROSS THE FORECAST AREA. A CHANGE IN THE UPPER PATTERN LOOKS TO BE IN THE OFFING FOR THE FIRST PART OF NEXT WEEK. MODELS ARE OFFERING A PLETHORA OF SOLUTIONS FOR NEXT MONDAY AFTERNOON. THE GFS OPERATIONAL RUN SPREADS A STRONG PUSH OF CANADIAN AIR ACROSS THE NORTHERN AND CENTRAL ROCKIES...WHILE THE ECMWF DEVELOPS A MORE CLOSED SYSTEM OVER THE GREAT BASIN WHICH WOULD DELAY ANY COLD AIR MOVING INTO COLORADO UNTIL THE UPPER LOW MOVES OVER THE STATE. IT IS HARD TO TELL WHICH SOLUTION IS GOING TO BE RIGHT...SO FOR THE TIME BEING WILL STICK WITH A SLIGHT CHANCE OF RAIN AND SNOW OVER THE FORECAST AREA ON MONDAY WITH COOLER TEMPERATURES THAN OVER THE WEEKEND. AVIATION...VFR CONDITIONS WILL PERSIST THROUGH TONIGHT. SLIGHTLY ENHANCED DRAINAGE WEST/SOUTHWEST WINDS THIS MORNING WILL MOST LIKELY TRANSITION TO LIGHT/VARIABLE BY 15Z-17Z...NORTHEAST BY 19Z-20Z...AND THEN SOUTHEAST BY 23Z-01Z. SPEEDS AFTER 15Z WILL BE AROUND 10KTS OR LESS. THERE IS A CHANCE OF AN ANTICYCLONE DEVELOPING WHICH WOULD PRODUCE A MORE SOUTHEASTERLY COMPONENT DURING THE AFTERNOON. KBJC MAY SEE A FEW WESTERLY GUSTS TO AROUND 20KTS TIL 15Z. 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 MIAMI FL
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. && $$ DISCUSSION/MARINE/FIRE...85/AG AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
238 PM CDT TUE OCT 22 2013 .DISCUSSION... 1035 AM CDT RATHER IMPRESSIVE SYSTEM CONTINUES TO PUSH PRECIP TOWARD THE FORECAST AREA LATE THIS MORNING. SURFACE ANALYSIS SHOWS LOW PRESSURE CENTERED NEAR OR JUST NORTH OF KIRKSVILLE MISSOURI WITH PRESSURE FALLS SUPPORTING A EAST-SOUTHEAST MOVEMENT OVER THE NEXT FEW HOURS. WATER VAPOR IMAGERY SHOWS THE UPPER TROUGH/VORT MOVING EASTWARD INTO NORTH CENTRAL ILLINOIS WHILE RADAR IMAGERY SHOWS A BAND OF PRECIP WORKING EASTWARD ACROSS THE QUAD CITIES AND EXTENDING SOUTHWARD DOWN THE MISSISSIPPI RIVER VALLEY. THE BULK OF THE PRECIP SHIELD LINES UP WITH WITH NEAR TERM DEPICTIONS OF 850-700 MB FRONTOGENESIS ACROSS FAR EASTERN IOWA INTO WESTERN ILLINOIS. RECENT OBS/WEBCAMS/REPORTS SHOW THAT MODERATE TO EVEN HEAVY SNOW IS FALLING OVER THE QUAD CITIES WITH SEVERAL INCHES QUICKLY ACCUMULATING ON GRASSY SURFACES/CARS/ROOFTOPS. THE CUTOFF TO RAIN OCCURS PRETTY QUICKLY JUST SOUTH AND EAST OF THE QUAD CITIES. ANOTHER BAND OF LIGHTER REFLECTIVITY EXTENDS FROM VINTON IOWA EAST TO SAVANNA TO ROCHELLE AND NEAR DEKALB WHICH HAS BEEN A MIX OF SNOW TO THE WEST WITH ROCHELLE NOW COMING IN WITH LIGHT RAIN. THIS AREA IS FORCED FROM A HIGHER LEVEL...LINING UP WELL WITH 700-600 MB FGEN. CLOUD BASES ARE STILL PRETTY HIGH WITH THIS AREA SUGGESTING DRY AIR IS INHIBITING PRECIP FROM MAKING IT TO THE GROUND BUT THIS FORCING IS EXPECTED TO REMAIN ORGANIZED AS IT SHIFTS EASTWARD AND EVENTUALLY SLIGHTLY NORTHEASTWARD OVER SOUTHERN LAKE MICHIGAN BY LATE AFTERNOON. EXPECT THAT SOME LIGHT PRECIP...PROBABLY MOSTLY RAIN WILL FALL FROM THIS AREA INTO THE MID AFTERNOON AFFECTING AREAS ALONG/NORTH OF THE INTERSTATE 88/INTERSTATE 290 CORRIDOR. AS FOR THE MAIN BAND OF PRECIP...FGEN WILL CONTINUE TO SHIFT EASTWARD AND FOCUS OVER THE CENTRAL/SOUTHERN CWA THROUGH THE AFTERNOON. OVERALL AREA OF POPS FROM THE EARLIER FORECAST STILL LOOKS GOOD FOCUSING THEM ALONG AND SOUTH OF INTERSTATE 80 WHICH LATEST RADAR TRENDS ALSO SUPPORT. PRECIP TYPE WILL REMAIN THE CHALLENGE WITH THE NARROW CORRIDOR OF MODERATE/HEAVY SNOW CURRENTLY OCCURRING LIKELY TRANSLATING EASTWARD TOWARD THE WESTERN CWA TOWARD EARLY AFTERNOON. TEMPS HAVE WARMED TO AROUND 40 BUT WITH EVAPORATIVE COOLING AND THE INTENSE PRECIP TEMPS WILL LIKELY FALL BACK INTO THE LOW/MID 30S AS THE BAND ARRIVES ASSUMING IT MAINTAINS INTENSITY. THE MOST LIKELY AREA FOR SNOW LOOKS TO BE RIGHT ALONG AND JUST SOUTH OF INTERSTATE 80 ACROSS SOUTHERN LASALLE AND GRUNDY COUNTIES AND ALONG THE WILL/KANKAKEE BORDER AREA GIVEN THAT TEMPS MAY REMAIN JUST COLD ENOUGH WITH PRECIP INDUCED COOLING TO MAINTAIN SNOW. GRASSY AREAS WOULD BE THE MAIN AREA OF ACCUMULATION WITH SOME BRIEF SLUSH ACCUMULATION ON LESS TRAVELLED ROADWAYS POSSIBLE. UNFORTUNATELY...THERE IS STILL MUCH UNCERTAINTY IN IF ALL SNOW WILL OCCUR FOR ANY LENGTH OF TIME GIVEN THE MARGINAL TEMPS ETC. AHEAD OF THE PRECIP BUT THE ABOVE OUTLINED AREA LOOKS MOST SUSCEPTIBLE. AREAS FURTHER SOUTH LOOK TO BE RAIN. MDB //PREV DISCUSSION... 343 AM CDT USUALLY IT WOULD BE ANOTHER FEW WEEKS OR EVEN LONGER IN OUR FORECAST AREA BEFORE INTERROGATING SEVERAL OF THE FORECAST INGREDIENTS THAT WERE THE FOCUS THIS MORNING. CHALLENGES WERE LOOKING AT PRECIP TYPE AND INTENSITY TODAY...TO SEE IF SOME PLACES COULD GET SOME BRIEF ACCUMULATION NAMELY NEAR THE I-80 /FIRST SUCH ACCUMULATION IN OVER 15 YEARS AND LONGER FOR SOME/...AND THEN LOOKING AT LAKE EFFECT PRECIP POTENTIAL AND TYPE FOR MAINLY PORTER COUNTY INDIANA LATE TONIGHT AND WEDNESDAY MORNING. SYNOPSIS...VIGOROUS SHORT WAVE ENTERING WESTERN IA EARLY THIS MORNING ON A 120+ JET IS BEGINNING TO CURL MORE SE AROUND THE BASE OF THE LONG WAVE TROUGH RESPONSIBLE FOR OUR COLD LATE OCTOBER SNAP. A SURFACE REFLECTION IS DEPICTED IN OBSERVATIONS WITH A BROAD LOW ACROSS WESTERN IA WHICH WILL TIGHTEN AND DEEPEN THROUGH THIS MORNING. SOME LIGHT RAIN IS SEEN ACROSS PARTS OF CENTRAL AND WESTERN IA IN THE WARM AIR ADVECTION FLANK OF THIS CLIPPER. MODEL PREFERENCE...MODEL GUIDANCE IS IN GOOD GENERAL AGREEMENT OF THIS WAVE TRANSITIONING EAST SOUTHEAST THIS AFTERNOON ACROSS CENTRAL IL WITH SOME VARIABILITY IN LATITUDE OF ITS KEY FEATURES...WHICH OF COURSE DICTATE ALL THE KEY ELEMENTS SUCH AS PLACEMENT OF HEAVIER PRECIP AND SUBTLE THERMAL DIFFERENCES THAT INFLUENCE WHERE TRANSITION TO RA/SN MIGHT OCCUR. HAD LEANED A LITTLE MORE TO THE 00Z NAM WHICH HAS VERY CLOSE SUPPORT BY THE 00Z EC AND THE 03Z SREF MEAN. IT SHOULD BE NOTED THIS 00Z NAM HAD SHIFTED SLIGHTLY FURTHER SOUTH THAN ITS PRECEDING 18Z RUN...AND NOW THE 06Z SOLUTION HAS EVEN SHIFTED A BIT FURTHER SOUTH. THE TREND FROM THAT OF TIGHTENING THE PRECIP GRADIENT ON THE NORTH SIDE HAS ALSO BEEN NOTED WHICH MAKES GOOD SENSE WITH HOW THIS SYSTEM IS ORIENTED AND ITS GENERALLY COMPACT NATURE AND QUICK MOVEMENT. THE MAIN POINT WITH THIS IS IT BASICALLY KEEPS PRECIP OUT OF CHICAGO. HAVE NOT GONE THAT SHARP BUT HAVE TIGHTENED THAT NORTHERN GRADIENT. TODAY AND TONIGHT...THE UPPER WARM AND MOIST ASCENT AHEAD OF THE CLIPPER SHOULD LEAD TO A BLOSSOMING OF RADAR ECHOES ACROSS THE WESTERN FORECAST AREA BY LATER THIS MORNING. GOOD CONVERGENCE AND THERMAL GRADIENT TIGHTENING IN THE MID-LEVELS...WITH SUPPORTIVE LAPSE RATES...WILL LIKELY CREATE SOME TEMPORARY MORE INTENSE WEST- TO-EAST CORRIDORS. MOST HIGH RESOLUTION GUIDANCE BOTH LOCALLY AND NATIONALLY TEND TO INDICATE THIS...ALTHOUGH AGAIN WITH DISCREPANCIES IN HOW FAR NORTH...SOME AS FAR NORTH AS AROUND I-88...OTHERS TOWARD PEORIA TO BLOOMINGTON/NORMAL. THIS HEAVIER PRECIP IS IMPORTANT BECAUSE MARGINAL THERMAL PROFILES WOULD NEED THE DIABATIC COOLING TO THE WET BULB /OR COOLER/ TO ENABLE SNOW TO MIX IN TO THE SURFACE. HAVE GENERALLY FAVORED THE LEE/LASALLE/LIVINGSTON COUNTIES THE MOST THIS AFTERNOON...AS THAT CORRIDOR OF WET BULB COOLING AT THE SURFACE /TEMPS DROPPING INTO THE MID 30S/ SHOULD BE SHIFTING SOUTHEAST THROUGH THOSE COUNTIES. IF SNOW CAN MATERIALIZE...TEMPORARY RATES COULD CERTAINLY BE ENOUGH TO BRING DOWN VISIBILITY QUICKLY...AND ITS POSSIBLE THOUGH NOT REALLY FAVORED TO SEE SOME LIGHT SLUSHY ACCUMULATION. LATE IN THE DAY AND THIS EVE THE PROFILES BECOME MORE SUPPORTIVE TO SEE A MIX ACROSS THE WHOLE AREA...BUT THE OVERALL STRONGER FORCING IS WEAKENING AS THE CLIPPER TRANSITIONS AWAY. SO REALLY NOT EXPECTING ANY ACCUMULATION ELSEWHERE IF ANY OTHER PLACES CAN ACTUALLY CHANGE OVER. IN MUCH OF THE CHICAGO METRO /OUTSIDE OF THE FAR SOUTHWEST AND SOUTH/ THE PROFILES JUST APPEAR TOO WARM TO SUPPORT A LONG CHANGEOVER IF ANY GIVEN MORNING MODERATION IN TEMPS. LAKE EFFECT...IN THE WAKE OF THE CLIPPER AND ITS SURFACE LOW REFLECTION MOVING INTO INDIANA...WINDS WILL TURN MORE NORTHERLY AND DOWN THE FETCH OF THE LAKE. IT APPEARS THEIR IS A 6 TO 12 HOUR WINDOW OF GOOD N-S CONVERGENCE INTO MAINLY NW IN. MODERATE TO EXTREME LOW-LEVEL INSTABILITY WILL BE IN PLACE OVER THE LAKE GIVEN 850MB TEMPERATURES OF -4C TO -6C. NAM PROFILES OVER THE LAKE GIVEN MODIFIED PARCELS NEAR THE SURFACE LAKE TEMPERATURES SUPPORT CLOUD DEPTHS OF 15K FT. ITS NOTED THIS MORNING THAT THE AIR TEMPERATURE AT THE SOUTH BUOY IS ONLY 42 DESPITE A WATER TEMPERATURE OF 60. SO THE INSTABILITY MAY NOT BE AS EXTREME AS SOME MODIFIED GUIDANCE SHOWS...BUT STILL AMPLE FOR DECENT SHOWERS. PRECIP TYPE IS A REAL CHALLENGE AND AGAIN BASED ON INTENSITY. IT WOULD SEEM ALONG THE IMMEDIATE LAKE SHORE WITH ONSHORE FLOW IT WOULD BE TOUGH TO GET EVEN A CHANGEOVER. INLAND THERE IS CERTAINLY THAT CHANCE AND IF THE CONVERGENCE IS STRONG...THEN THAT INSTABILITY WILL TRAIN INLAND POTENTIALLY CREATING A PROBLEM FOR QUICK ACCUMULATION IF COLD ENOUGH WITH HEAVY SUSTAINED RATES. HAVE ADDED UNDER AN INCH OF ACCUMULATION IN EASTERN PORTER COUNTY...BUT CERTAINLY THE CHANCE IS THERE FOR MORE. FOR NOW THOUGH...THERMAL PROFILES ARE AWFULLY MARGINAL AND WITH THE CAVEAT OF ONSHORE FLOW POTENTIALLY LEADING TO RAIN SHOWERS FOR MUCH OF THAT TIME. BEYOND...MORE TRANQUIL CONDITIONS PREVAIL HOWEVER STILL UNDER NORTHWEST FLOW ALOFT...SO BELOW NORMAL TEMPERATURES CONTINUE. THE BACK SIDE OF THE TROUGH SHIFTS EAST AS DOES ITS JET...SO THE PATH FOR SHORT WAVES WILL BE MORE TO THE NORTH AND EAST BY THURSDAY...MEANING LESS OF A CHANCE FOR PRECIP. LAKE EFFECT ORIENTATION LOOKS TO BE EAST OF OUR INDIANA COUNTIES ON MOST OF THESE DAYS. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * RAIN MIXING WITH AND CHANGING OVER TO WET SNOW THIS AFTERNOON AFTER 19 UTC. * VIS TO DROP AS LOW AS 1-2 MILES AND CIGS AROUND 1,000 FT FOR A PERIOD. BETTER CHANCES WILL BE AT MDW. KJB //DISCUSSION...UPDATED 18Z... THE MAIN FORECAST CONCERNS THIS AFTERNOON IS THE SNOW THAT WILL BE AFFECTING THE EASTERN TERMINALS THROUGH THE AFTERNOON. ALTHOUGH THE SNOW SHOULD NOT RESULT IN ACCUMULATIONS ON RUNWAYS...IT COULD REDUCE THE VISIBILITIES DOWN TO 1 TO 2 MILES FOR A PERIOD THIS AFTERNOON...ALONG WITH CIGS AROUND 1,000 FEET...ESPECIALLY AT KMDW AND KGYY. IT STILL APPEARS THE HEAVIEST PRECIP WILL BE FAVORED SOUTH WITH THIS SYSTEM. HOWEVER...THERE IS A BAND OF LIGHTER PRECIP MOVING ACROSS NORTHERN ILLINOIS AND THIS WILL LIKELY AFFECT ALL THE TERMINALS TO SOME POINT THIS AFTERNOON. I WENT WITH LOWER VIS AND CIGS AT KMDW AND KGYY AS THEY STAND THE BEST CHANCES FOR SOME SLIGHTLY HEAVIER PRECIP. IT COULD BEGIN AS SOME LIGHT RAIN INITIAL...BUT AS EVAPORATION COOLING TAKES OVER IT SHOULD MIX WITH AND CHANCE OVER THE SNOW. WITH SNOW LIKELY BECOMING THE MAIN PRECIP TYPE...THIS SHOULD LEAD TO LOWER VISIBILITIES THAN PREVIOUSLY FORECAST. WIND DIRECTIONS WILL BE A CHALLENGE THIS AFTERNOON...WITH THE LOW MOVING TO THE SOUTH. IT APPEARS THEY WILL BE OUT OF THE SOUTHWEST THROUGH THE AFTERNOON...THEN SHIFTING MORE NORTHWEST TONIGHT. WIND SPEEDS SHOULD REMAIN AT OR LESS THEN 10KT. CONDITIONS SHOULD IMPROVE THIS EVENING AS THE SYSTEM SHIFTS EAST OF THE AREA. KJB //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN PRECIP AFFECTING THE TERMINALS WITH RAIN/SNOW * MEDIUM CONFIDENCE IN PERIOD OF 1 TO 2 SM VIS RANGE THIS AFTERNOON IN -SN...ESPECIALLY AT KMDW. * LOW TO MEDIUM CONFIDENCE IN LOW MVFR CIGS AROUND 1,000 FT THROUGH THE AFTERNOON...WITH IFR POSSIBLE. KJB //OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z... WEDNESDAY NIGHT THROUGH FRIDAY...VFR. SATURDAY...MVFR POSSIBLE LATE. SUNDAY...VFR. MONDAY...CHANCE OF RAIN. JEE && .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
  [top] Area Forecast Discussion National Weather Service Lincoln IL 222 PM CDT Tue Oct 22 2013 .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 vortext 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 && .AVIATION... ISSUED 1237 PM CDT Tue Oct 22 2013 Main aviation forecast challenges will be timing of potential IFR ceilings into the area later this afternoon and evening...and timing the clearing trend later tonight. Low pressure currently over southeast Iowa will track E/SE across central Illinois this afternoon...accompanied by a band of light rain. Once the low passes, winds will swing around to the N/NE and should pull IFR ceilings currently in place across much of Iowa and northwest Illinois into the area. Model guidance is in disagreement, with the GFS and NAM indicating MVFR or even VFR ceilings persisting. Given latest satellite trends, prefer the more pessimistic HRRR which brings the lower ceilings into central Illinois behind the departing low. Based on HRRR timing, have introduced IFR ceiling at KPIA by 21z, then further east to KCMI by 02z. Clouds will be rather slow to clear tonight, with the HRRR hanging on to IFR conditions until around midnight. Skies should scatter at KPIA by 05z, then eastward to KCMI by around 10z. Barnes && .ILX WATCHES/WARNINGS/ADVISORIES... FREEZE WATCH from late Thursday night through Friday morning FOR ILZ062-063-066>068-071>073. FREEZE WARNING from 1 AM to 8 AM CDT Wednesday FOR ILZ027>031- 036>038-040>057-061. && $$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1220 PM CDT TUE OCT 22 2013 .UPDATE... ISSUED AT 1215 PM CDT TUE OCT 22 2013 DESPITE WEAK FORCING...PRECIPITATION HAS LINGERED ACROSS MUCH OF CWA THROUGH THE MORNING. THIS WILL CONTINUE TO PUSH SLOWLY SOUTHEAST THROUGH THE REMAINDER OF THE AFTERNOON. HAVE THEREFORE INCREASED POPS THROUGH THE AFTERNOON. IN ADDITION...WITH COLDER AIR WORKING IN BEHIND SYSTEM PRECIPITATION HAS CHANGED TO SNOW ACROSS MUCH OF CENTRAL IOWA...AND HAVE INTRODUCED POSSIBLE ACCUMULATIONS NEAR 0.1 OF AN INCH A FEW COUNTIES FURTHER SOUTH. && .SHORT TERM /TODAY/... ISSUED AT 341 AM CDT TUE OCT 22 2013 MAIN CONCERN TODAY WILL OBVIOUSLY BE EVOLUTION OF CURRENT SYSTEM PASSING THROUGH THE MO VALLEY. DAKOTAS SHORT WAVE/PV ANOMALY CONTINUES TO STRENGTHEN AS IT APPROACHES WRN IA. ASSOCIATED PRECIP IS CURRENTLY SOMEWHAT PATCHY...LIKELY DUE TO FAIRLY LOW STATIC STABILITIES...BUT IS EXPECTED TO ORGANIZE SOMEWHAT MORE LATER THIS MORNING. FORCING IS DEEP...DRIVEN KINEMATICALLY BY DPVA AND DIVERGENCE IS LEFT EXIT REGION OF SASKATCHEWAN INTO HIGH PLAINS JET SEGMENT. THERMODYNAMIC FORCING IS CENTERED INTO IA AND CURRENTLY NOT THAT STRONG HOWEVER BUT MODELS DO STRENGTHEN THE THETA-E ADVECTION AND FRONTOGENETICAL FORCING INTO THE MORNING. THIS COUPLED FORCING WILL RESULT IN INCREASED DENDRITIC GROWTH ZONE /DGZ/ UPWARD MOTION. MODEL DEPICTIONS OF THIS...LOOKING AT 290-300K ISENT LAYER...ARE SOMEWHAT PROBLEMATIC HOWEVER AND AFOREMENTIONED LOW STATIC STABILITIES HAVE RESULTED IN COMPACT MODEL BULLSEYES OF LIFT WHICH ARE DIFFICULT TO EASILY TRANSLATE INTO HIGHER SNOW RATIOS AND RESULTANT SENSIBLE WEATHER. AREAS OF HIGHER SNOW RATES MAY END UP BEING NEAR CONVECTIVE AND SOMEWHAT ISOLATED. TO LOWER CONFIDENCE EVEN FURTHER...LOWEST 500M TEMPS HOVER RIGHT AROUND CRITICAL RAIN/SNOW VALUES WHICH ARE CO-LOCATED WITH THE DGZ LIFT. THIS MAKES RAIN/SNOW LINE UNCERTAIN AND WHETHER THE DGZ OMEGA WILL BE REALIZED IN RAIN OR SNOW. TAKING A BLEND OF THE HIGHER RES RAP AND NAM WOULD SUGGEST THE BEST LOCATION FOR ACCUMULATING SNOWS WOULD BE SIMILAR TO PREVIOUS TRACK FROM NW IA SEWD TO NEAR WATERLOO AND MARSHALLTOWN. STILL HAVE ACCUMS OF AN INCH OR LESS...WITH A POCKET OF HIGHER AMOUNTS NEAR AN IOWA FALLS/MARSHALLTOWN/WATERLOO TRIANGLE WHERE SNOW MAY BRIEFLY INTENSIFY AROUND 12Z OR 15Z. CONFIDENCE IN SNOW AMOUNTS IS QUITE LOW HOWEVER DUE TO CONCERNS ABOVE AND MELTING ISSUES WITH ROAD SURFACE TEMPS STILL 35F OR HIGHER AND THE GROUND WARM AS WELL. .LONG TERM /TONIGHT THROUGH MONDAY/... ISSUED AT 341 AM CDT TUE OCT 22 2013 MAIN FORECAST CONCERN IS WITH WEAK SHORTWAVE TO BRING ADDITIONAL PRECIP CHANCES ON WEDNESDAY AND THEN CONTINUED COLD TEMPERATURES THROUGH THE END OF THE WORK WEEK AND INTO THE WEEKEND. TONIGHT THROUGH WEDNESDAY...THE 22.00Z MODELS RUNS IN DECENT AGREEMENT WITH BRINGING WEAK VORT MAX FURTHER SOUTH AND CAUSED FOR A SHIFT IN POPS SOUTHWEST LEAVING THE NORTHEAST PORTIONS OF THE FORECAST AREA DRY TOMORROW. THERE IS A SMALL WINDOW FOR SNOW POTENTIAL DURING THE MORNING...ROUGHLY BETWEEN 12-15Z WEDNESDAY WHEN THE COLUMN BECOMES SATURATED AND REMAINS BELOW FREEZING AND ENOUGH FORCING IN THE SNOW GROWTH ZONE TO GENERATE SNOW. THIS WILL BE MAINLY OVER WEST CENTRAL TO NORTHWEST IOWA. HOWEVER...LOW CONFIDENCE WITH MUCH...IF ANY SNOW ACCUMULATION AS SURFACE TEMPERATURES LOOK TO QUICKLY RISE ABOVE FREEZING AND FORCING QUICKLY MOVES SOUTH. AS A RESULT...DECREASED SNOW AMOUNTS TO LESS THAN HALF AN INCH. THETA-E ADVECTION AND ISENTROPIC LIFT WILL QUICKLY MOVES FROM NORTHWEST IOWA TO SOUTHEAST IOWA DURING THE DAY WEDNESDAY. NAM/GFS HAVE DECENT FRONTOGENETICAL FORCING BETWEEN 750-600MB BY 12Z IN NORTHWEST IOWA AND THEN TRANSITION THE FORCING INTO SOUTH-CENTRAL TO SOUTHEAST PORTIONS OF THE FORECAST AREA BY 18Z. WITH THE QUICKER MOVEMENT OF THE SYSTEM...DECREASED POPS OVER THE WEST AND NORTH PAST 21Z. THURSDAY THROUGH MONDAY....LARGE SURFACE HIGH BUILDS INTO THE REGION UNDERNEATH NORTHWEST FLOW ALOFT THROUGH SATURDAY BEFORE THE GFS/ECMWF BRING A DRY COLD FRONT ACROSS THE STATE SOMETIME SATURDAY. NEXT LONGWAVE TROUGH BEGINS TO DIG INTO THE WESTERN U.S. BY EARLY NEXT WEEK PLACING AN INVERTED SURFACE TROUGH OVER IOWA BY MONDAY. THIS WILL BE THE NEXT BEST CHANCE OF PRECIP TO THE FORECAST AREA. && .AVIATION...22/18Z ISSUED AT 1215 PM CDT TUE OCT 22 2013 LIGHT PRECIPITATION WILL LINGER WITH MVFR CEILING AND VISIBILITIES AT SITES...WITH EXCEPTION OF KMCW WHICH WILL REMAIN NORTH AND IN VFR CONDITIONS. BEHIND PRECIPITATION CEILINGS WILL SLOWLY LIFT BACK TO VFR CEILINGS...GENERALLY NEAR 00Z AT SITES. WINDS WILL SHIFT TO THE WEST THROUGH THE PERIOD. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ UPDATE...AWB SHORT TERM...SMALL LONG TERM...PODRAZIK AVIATION...AWB
AREA FORECAST DISCUSSION
NWS WICHITA KS
1154 AM CDT TUE OCT 22 2013 .UPDATE... ISSUED AT 712 AM CDT TUE OCT 22 2013 THIS MORNING: THE PURPOSE FOR THE UPDATE IS TWO-FOLD: 1) TO REMOVE SPRINKLES FROM PARTS OF CENTRAL & SOUTH-CENTRAL KS. 2) TO ADJUST CLOUD COVER TO REFLECT SATELLITE TRENDS TO FOCUS CLOUD COVER OVER SE KS THIS MORNING. && .SHORT TERM...(TODAY THROUGH THURSDAY) ISSUED AT 333 AM CDT TUE OCT 22 2013 TODAY: ADDED A FEW SPRINKLES THIS MORNING BASED ON RADAR/SURFACE OBSERVATIONS...WITH RUC SHOWING TRANSIENT LIFT MOISTURE TRACKING ACROSS EASTERN EDGE OF FORECAST AREA EARLY THIS MORNING. OTHERWISE IT IS A CHALLENGING TEMPERATURE FORECAST WITH A LOT RIDING ON WIND DIRECTION AND CLOUDS. RELATIVELY DRY AIRMASS AND POSSIBLE DOWNSLOPE FLOW COULD REALLY BOOST TEMPERATURES THIS AFTERNOON. GIVEN SLIGHT COOL BIAS YESTERDAY AND WHAT SHOULD BE FAIRLY GOOD BREAKS IN CLOUDS LATER...WILL HEDGE A COUPLE DEGREES WARMER TODAY AND HOPEFULLY MINIMIZE ERROR EITHER WAY. TONIGHT: RIDGE AXIS WILL SETTLE OVER AREA WITH A SHARP FALL IN TEMPERATURES EARLY. SOME RETURN FLOW/CLOUDS MAY DEVELOP AFTER MIDNIGHT ACROSS WESTERN SECTIONS. HOWEVER CONDITIONS APPEAR FAVORABLE FOR WIDESPREAD FROST OVER FLINT HILLS/SOUTHEAST KS WHERE WINDS WILL LIKELY REMAIN NEAR CALM ALL NIGHT. WILL HOIST HEADLINES FOR FROST ADVISORY IN MOST LIKELY AREAS AND LET DAY SHIFT ADJUST WESTWARD IF NEEDED. WED-THU: QUICK WARM-UP SHOULD COMMENCE ON WED WITH GOOD WARMING JUST AHEAD OF NEXT FRONT THAT TRAVERSE MOST OF THE AREA DURING THE DAY. TEMPERATURES WILL LIKELY FALL IN THE AFTERNOON ACROSS NORTHERN HALF OF THE AREA AND WILL HAVE NON DIURNAL TEMPERATURES IN GRIDS. TOUGH CALL ON TEMPERATURES WED NIGHT WITH WIND INITIALLY...BUT WITH RIDGING BUILDING INTO AREA...MAY SEE TEMPERATURES TUMBLE TOWARDS DAYBREAK...MOST LIKELY IN SOUTHEAST KS. COLD AIR ADVECTION CONTINUES ON THU WITH MAXES 10-15 DEGREE COOLER THAN WED. LACK OF MOISTURE SHOULD PRECLUDE ANY MENTION OF PRECIPITATION. -HOWERTON .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 333 AM CDT TUE OCT 22 2013 MEDIUM RANGE MODELS STILL IN FAIRLY GOOD AGREEMENT GIVEN THE TYPICAL ISSUES OF TIMING SHORTWAVES IN NORTHWEST FLOW. RETURN FLOW ON FRI...WITH COLD FRONT MOVING THROUGH ON SAT. RETURN FLOW DEVELOPS SUN NIGHT AND PERSISTS INTO MON. SOME DIFFERENCES IN TIMING OF FRONT...BUT SMALL CHANCES CERTAINLY JUSTIFIED ON MON ACROSS SE KS. GIVEN RETURN OF CLOUDS AND INFLUX OF MOISTURE...HAVE BUMPED UP LOWS FOR MON. DIURNAL RANGE MAY BE EVEN MORE LIMITED ON MON IN SE KS WHERE LOW CLOUDS AND PRECIPITATION COULD PERSIST MOST OF THE DAY. -HOWERTON && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1150 AM CDT TUE OCT 22 2013 NORTHWESTERLY WINDS WILL GUST TO 24-30 KT THIS AFTERNOON...BEFORE DIMINISHING AND BECOMING LIGHT NORTHEASTERLY THIS EVENING. WINDS WILL THEN BECOME SOUTH-SOUTHWESTERLY BY LATE WEDNESDAY MORNING. SOME MID-LEVEL ALTOCUMULUS MAY AFFECT ESPECIALLY NORTHEASTERN KS TONIGHT IN THE NORTHWEST FLOW ALOFT. JMC && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 70 39 71 38 / 0 0 0 0 HUTCHINSON 70 38 69 37 / 0 0 0 0 NEWTON 69 38 69 36 / 0 0 0 0 ELDORADO 69 35 69 36 / 10 0 0 0 WINFIELD-KWLD 71 37 73 38 / 0 0 0 0 RUSSELL 67 37 67 34 / 0 0 0 0 GREAT BEND 68 37 68 34 / 0 0 0 0 SALINA 67 36 69 36 / 0 0 0 0 MCPHERSON 69 37 69 36 / 0 0 0 0 COFFEYVILLE 69 36 69 38 / 10 0 0 0 CHANUTE 67 33 65 35 / 10 0 10 0 IOLA 65 32 65 35 / 10 0 10 0 PARSONS-KPPF 67 33 67 34 / 10 0 0 0 && .ICT WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY FROM 1 AM TO 9 AM CDT WEDNESDAY FOR KSZ052-053- 069>072-094>096-099-100. && $$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
610 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/... 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 /22Z TUESDAY THROUGH SUNDAY/... NEAR TERM: A BRIEF PERIOD OF MVFR THIS EVENING W/THE COLD FROPA AND THEN VFR RIGHT INTO WEDNESDAY. SHORT TERM: CONDITIONS ARE EXPECTED TO IMPROVE TO VFR WEDNESDAY NIGHT THEN BE VFR ON THURSDAY. CONDITIONS MAY 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 SATURDAY NIGHT. && .MARINE... NEAR TERM: SEAS HAVE CONTINUED TO BUILD THIS AFTERNOON AND ARE NOW RUNNING AROUND 5 FT AT THE EASTERN MAINE SHELF AS OF 5 PM EDT. THE SCA TO STAY UP THROUGH MIDNIGHT. EXPECTING GUSTS TO 25KT THROUGH MIDNIGHT AND THEN GRADIENT IS EXPECTED TO WEAKEN AS THE COLD FRONT PASSES THROUGH THE WATERS. SW WINDS EXPECTED TO SHIFT TO THE WNW LATER TONIGHT INTO WEDNESDAY. WINDS WILL DROP OFF TO 10 KT BY 12Z WEDNESDAY W/SEAS DROPPING OFF TO LESS THAN 3 FT. 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...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ050>052. && $$ NEAR TERM...CB/HEWITT SHORT TERM...BLOOMER LONG TERM...BLOOMER AVIATION...CB/HEWITT/BLOOMER MARINE...CB/HEWITT/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
336 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/... 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 PRICIPIATION 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 /18Z TUESDAY THROUGH SUNDAY/... NEAR TERM: A BRIEF PERIOD OF MVFR THIS EVENING W/THE COLD FROPA AND THEN VFR RIGHT INTO WEDNESDAY. SHORT TERM: CONDITIONS ARE EXPECTED TO IMPROVE TO VFR WEDNESDAY NIGHT THEN BE VFR ON THURSDAY. CONDITIONS MAY 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 SATURDAY NIGHT. && .MARINE... NEAR TERM: SCA TO STAY UP THROUGH MIDNIGHT. GUSTS ARE UP TO 20KT ATTM W/SEAS NOW UP TO 4 FT AS OF 18Z OBS. EXPECTING GUSTS TO 25KT THROUGH MIDNIGHT AND THEN GRADIENT IS EXPECTED TO WEAKEN AS THE COLD FRONT PASSES THROUGH THE WATERS. SW WINDS EXPECTED TO SHIFT TO THE WNW LATER TONIGHT INTO WEDNESDAY. WINDS WILL DROP OFF TO 10 KT BY 12Z WEDNESDAY W/SEAS DROPPING OFF TO LESS THAN 3 FT. 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...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ050>052. && $$ NEAR TERM...HEWITT SHORT TERM...BLOOMER LONG TERM...BLOOMER AVIATION...HEWITT/BLOOMER MARINE...HEWITT/BLOOMER
AREA FORECAST DISCUSSION
NWS CARIBOU ME
126 PM EDT TUE OCT 22 2013 .SYNOPSIS... A COLD FRONT IS THEN EXPECTED TO MOVE ACROSS THE REGION THIS EVENING. ANOTHER WEAK LOW PRES WILL MOVE EAST...NORTHEAST FROM THE MID ATLANTIC STATES TO SOUTH OF NOVA SCOTIA ON WEDNESDAY.&& .NEAR TERM /THROUGH TONIGHT/... 125 PM UPDATE...ADJUSTED THE PRECIP CHANCES TO ALIGN W/THE LATEST RADAR TRENDS SHOWING 2 AREAS OF SHOWERS W/ONE AREA MOVING ACROSS WASHINGTON COUNTY AND THE OTHER AREA(MORE OF A LINE) MOVING INTO NORTHERN AND CENTRAL MAINE AHEAD OF THE COLD FRONT. THIS AREA APPEARS TO BE ALIGNED W/A PRE-FRONTAL TROF AS INDICATED BY THE 16Z SFC ANALYSIS. VELOCITY FIELDS INDICATE GUSTS TO 40 KTS AT 5KT FT. THEREFORE, INCREASED WIND GUSTS THIS AFTERNOON TO 30 MPH AND MOVED THREAT OF THUNDER S OF A CARIBOU TO BAXTER STATE LINE. THIS BASED ON LATEST LAPS SOUNDINGS SHOWING ANY INSTABILITY S OF THE LINE. PREVIOUS DISCUSSION... SOUTH FLOW WILL INCREASE AHEAD OF THE APPROACHING FRONT, USHERING IN MOISTURE AND RELATIVELY MILD AIR. THE GFS AND NAM INDICATE LAPSE RATES AROUND 6.5C/KM AND 0-6KM SHEAR RUNNING AROUND 40 KT, BOTH OF WHICH WOULD HELP CONVECTION SET UP. ALSO NOTE THAT THE LATEST HRRR HINTS AT A LINE OF HIGHER REFLECTIVITY COINCIDENT WITH THE FRONT THIS AFTERNOON. HAVE THEREFORE LEFT ISOLATED THUNDER IN THE FORECAST FOR THIS AFTERNOON FOR MUCH OF THE FORECAST AREA, THOUGH DOWNEAST AREAS HAVE THE BEST CHANCES OF ACTUALLY SEEING ANY THUNDERSTORMS. GIVEN THE AFOREMENTIONED SHEAR, GUSTY WINDS WILL BE POSSIBLE IN ANY OF THE STRONGER ACTIVITY, REGARDLESS OF WHETHER OR NOT THERE IS THUNDER. OVERALL, EXPECT ABOUT A THIRD OF AN INCH OF RAIN AT MOST, WITH MUCH OF THE AREA SEEING LESS THAN A QUARTER OF AN INCH BY TONIGHT. FOR TONIGHT...THE FRONT WILL EXIT INTO NEW BRUNSWICK THIS EVENING, WITH THE RAIN COMING TO A QUICK END THEREAFTER. MUCH COOLER AND DRIER AIR WILL FOLLOW IN THE FRONT`S FOOTSTEPS, LEADING TO CLEARING SKIES AND COOLING TEMPERATURES. OVERNIGHT LOWS WILL BE IN THE LOWER 30S NORTH, WITH THE USUAL COLD SPOTS ACROSS THE NORTHWEST DROPPING INTO THE 20S. CENTRAL AND SOUTHERN AREAS WILL SEE MID 30S, WITH THE COAST BOTTOMING OUT AROUND 40. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... MODELS CONT TO AGREE ON A WEAK LOW PRES SYSTEM WITH AN ALBERTA CLIPPER LIKE S/WV FROM THE OH VLY MOVG ENE FROM THE MID ATLC STATES WED TO S OF NOVA SCOTIA WED NGT. THIS SYSTEM WILL BRING CLDNSS TO THE CNTRL AND DOWNEAST PTNS OF THE FA WED INTO WED EVE ALG WITH THE POSSIBILITY OF LGT RNFL TO DOWNEAST TO PERHAPS AS FAR N AS E CNTRL PTNS OF THE FA BY ERLY WED EVE. IN ANY EVENT... THE BEST POTENTIAL OF RNFL WITH THIS SYS APPEARS TO BE FAR SE ME... BUT EVEN HERE...6 HRLY QPF AMOUNTS LOOK TO BE LGT...AND THERE MAY BE EVEN A SHARPER SE TO NW CUT-OFF OF PRECIP THEN WHAT WE INDICATE WITH THE GFS (ONE OF THE MODELS IN THE BLEND WE USED) LIKELY TO GENEROUS WITH QPF NWRD INTO ME WHERE LLVL DRY AIR MAY RESULT IN SIG EVAPORATION. IN ANY EVENT...PRECIP FROM THIS LOW SHOULD EXIT THE FA LATE WED NGT. IN THE WAKE OF THIS LOW...MDT TO STRONG LLVL COLD ADVCN WILL BEGIN ACROSS THE FA ERLY THU AND CONT INTO THU EVE. IN ADDITION...AN UPPER LVL TROF WILL BRING SC TO SPCLY WRN AND NRN PTNS OF THE FA WITH THE POSSIBILITY OF RN AND HIER TRRN SN SHWRS. AFT THE PASSAGE OF THE UPPER TROF LATE THU NGT...WINDS SHOULD SUBSIDE SOMEWHAT AND SHWRS SHOULD MSLY DISSIPATE TO SCT FLURRIES. BOTH DAY AND NGT TM TEMPS WILL BE ON THE DECLINE EACH PD OF THE SHORT TERM AS PROGRESSIVELY COLDER AIR CROSSES INTO THE FA FROM QB PROV. && .LONG TERM /FRIDAY THROUGH MONDAY/... OVERALL CONTD CHILLY AND UNSETTLED OVR THE FA THRU THE LONG TERM WITH SIG BLO NORMAL TEMPS. FRI CONTS TO LOOK BREEZY AND CHILLY...BUT NOT AS BRISK AS THU. CANNOT RULE OUT SCT FLURRIES OR SPRINKLES OVR THE W AND N... BUT EVEN HERE THERE SHOULD BE PARTIAL CLRG FRI NGT AS A WEAK SFC RIDGE BRIDGES INTO THE FA FROM THE OH VLY. SAT WILL BEGIN BUT HI AND MID CLDNSS WILL INCREASE FROM THE W LATER IN THE DAY ANOTHER ALBERTA CLIPPER S/WV MOVES TOWARD THE FA FROM THE GREAT LKS. DESPITE THE INITIAL SRLY LLVL WINDS THAT SETS UP WITH THE ONSET OF PRECIP SAT NGT WITH THIS S/WV...THE COMBO OF EVAPORATIONAL AND WEAK DYNAMIC COOLING FROM PRECIP FALLING FROM MID CLD LVL MAY RESULT IN A CHG OVR OF LGT RN TO LGT WET SN LATE SAT NGT/ERLY SUN MORN OVR NRN PTNS OF THE FA...SPCLY IF THE COLDER 00Z ECMWF SOLUTION VERIFIES...WHICH IMPLIES A WEAK SECONDARY SPOT LOW ON THE OCCLUSION PT BY ERLY SUN AFTN. FOR THIS REASON WE INTRODUCE A CHC OF SN WITH THIS SYSTEM ACROSS THE N AND A MIX OF LGT RN/SN OVR E CNTRL AND INTERIOR DOWNEAST PTNS OF THE FA LATE SAT NGT/ERLY SUN MORN... WITH COASTAL DOWNEAST AREAS REMAINING LGT RN DUE TO THE BL INFLUENCE OF MILD MARINE AIR ADVCTG OVR THIS AREA ON S WINDS. ATTM...QPF LOOKS TO BE FAIRLY LGT...BUT CANNOT RULE OUT AN INCH OR TWO OF WET SNFL OVR THE HIER TRRN OF THE NW...WITH LESSER AMOUNTS S AND E. ANY STEADY PRECIP SUN MORN SHOULD QUICKLY EXIT E OF THE FA BY MIDDAY SUN AS THE S/WV TRACKS E OF THE FA...LEAVING MSLY SCT AFTN RN SHWRS...POSSIBLY STILL MIXED WITH WET SN OVR VERY HIGH TRRN. FAIR CONDITIONS WITH CLRG OVR THE SRN TWO THIRDS OF THE FA CAN BE XPCTD SUN NGT WITH CONTD CHILLY CONDITIONS ON MON. && .AVIATION /17Z TUESDAY THROUGH SATURDAY/... NEAR TERM: CONDITIONS WILL GENERALLY BE VFR THROUGH THIS MORNING, THOUGH MVFR CEILINGS WILL BE LIKELY AT KFVE. SHOWERS WILL BE WINDING DOWN FOR A BIT THIS MORNING, BUT THEY WILL RETURN THIS AFTERNOON AS A COLD FRONT MOVES FROM WEST TO EAST. MVFR CEILINGS WILL PREVAIL (IFR AT KFVE) AT THE NORTHERN TERMINALS, BUT KBGR AND KBHB SHOULD REMAIN VFR THROUGH THE PERIOD. THE RAIN WILL END SHORTLY AFTER 00Z, SO EXPECT CLOUDS TO LIFT TO VFR AT ALL SITES BY 06Z. SHORT TO LONG TERM: VFR XPCTD WED INTO WED EVE FOR NRN TAF SITES WITH MVFR POSSIBLE FOR DOWNEAST SITES DUE TO LOW CLGS AND INTERMITTENT LGT RNFL WITH A DISTANT OFFSHORE ATLC LOW PRES SYSTEM. VFR CONDITIONS SHOULD RETURN FOR DOWNEAST SITES WHILE NRN TAF SITES BECOME MVFR VERY LATE WED NGT IN BKN-OVC SC AND ANY RN/SN SHWRS WITH LLVL COLD ADVCN AND THE APCH OF AN UPPER TROF...AND THIS TREND SHOULD CONT THRU THU NGT...AFT WHICH ALL SITES SHOULD BE VFR FRI AFT THE PASSAGE OF THE UPPER TROF AND CONT SO THRU SAT. && .MARINE... NEAR TERM: A SMALL CRAFT ADVISORY REMAINS IN EFFECT FROM NOON TODAY TO MIDNIGHT TONIGHT. SOUTH WINDS WILL INCREASE THROUGH THE MORNING HOURS AHEAD OF AN APPROACHING COLD FRONT, BECOMING 15 TO 20 KT WITH GUSTS TO AROUND 25 KT BY LATE AFTERNOON. THIS WILL ALLOW SEAS TO BUILD TO AROUND 5 FT. CONDITIONS WILL IMPROVE LATE TONIGHT BEHIND THE FRONT. SHORT TO LONG TERM: WE STILL XPCT MDT TO STRONG SCA CONDITIONS OVR OUR WATERS THU INTO THU NGT WITH STRONG LLVL COLD ADVCN BEHIND A DEVELOPING LOW PRES SYS OVR THE ERN MARITIMES. WINDS AND WVS WILL DIMINISH BLO SCA CRITERIA ON FRI AS THE LOW MOVES INTO THE OPEN ATLC...WITH BLO SCA CONDITIONS XPCTD TO LAST THRU SAT. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ050>052. && $$ NEAR TERM...HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
119 PM EDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 520 AM EDT TUE OCT 22 2013 WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE INTO THE WRN CONUS AND A BROAD DOWNSTREAM TROUGH OVER THE CNTRL AND ERN CONUS. A MID LEVEL LOW JUST NORTH OF THE SAULT WAS LIFTING SLOWLY TO THE ENE. AT THE SFC...LOW PRES WAS LOCATED A THE SRN END OF JAMES BAY WITH A TROUGH EXTENDING TO THE SW THROUGH ERN LAKE SUPERIOR INTO ERN UPPER MI. AFTER A BRIEF PERIOD OF MODERATE TO HEAVY SNOW ASSOCIATED WITH LOW LEVEL CONV AHEAD OF THE TROUGH...WIND PARALLEL SNOW BANDS HAVE DEVELOPED BUT WITH LESS ORGANIZED CONVECTIVE ELEMENTS. SNOWFALL AMOUNTS WERE IN THE 1 TO 3 INCH RANGE OVER THE WEST DURING THE EVENING BUT HAVE ONLY AMOUNTED TO LESS THAN INCH OVER N CNTRL UPPER MI NEAR NEGAUNEE. WITH LOW LEVEL TEMPS NEAR FREEZING AND MILD AIR MOVING IN FROM THE RELATIVELY WARM LAKE SUPERIOR...WATER TEMPS IN THE UPPER 40S...WET BULB ZERO HEIGHTS HAVE REMAINED HIGH ENOUGH FOR THE SNOW TO CHANGE BACK TO MAINLY RAIN OVER THE KEWEENAW AND ALONG LAKE SUPERIOR TO THE EAST. TODAY...EXPECT THE LAKE ENHANCED SNOW BANDS TO CONTINUE AS CAA DROPS 850 MB TEMPS FROM AROUND -7C TO NEAR -9C. HOWEVER...WITH DRIER AIR MOVING INTO THE REGION AND LOWER INVERSION HEIGHTS IN THE PRESENCE OF SYNOPTIC SCALE SUBSIDENCE BEHIND THE DEPARTING MID LEVEL LOW...THE SNOW SHOWER INTENSITY/COVERAGE WILL DIMINISH THIS MORNING LEAVING JUST SCT LIGHT SNOW/RAIN SHOWERS BY AFTERNOON. TONIGHT...THE MODELS SUGGEST A WEAK SHORTWAVE TROUGH MAY SLIDE INTO THE AREA. WITH 850 MB TEMPS REMAINING NEAR -8C...AN INCREASE IN 850-700 MB MOISTURE...AND MORE FAVORABLE LOW LEVEL CONV AS LAND BREEZES DEVELOP...SNOW SHOWERS ARE EXPECTED TO INCREASE FOR LOCATIONS FAVORED TY NW TO WNW FLOW. HOWEVER...GIVEN THE MARGINAL INSTABILITY...ANY ACCUMULATIONS ARE EXPECTED TO REMAIN AT AN INCH OR LESS. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 350 AM EDT TUE OCT 22 2013 THE UPPER GREAT LAKES WILL STILL BE UNDER THE WESTERN SIDE OF THE UPPER TROUGH AT THE START OF THE LONG TERM PERIOD...WHICH WILL REMAIN IN PLACE THROUGH THURSDAY NIGHT. AT THE SURFACE...A LOW WILL BE LOCATED TO THE EAST OF JAMES BAY AND HIGH PRESSURE WILL BE SLIDING SOUTHEAST THROUGH THE NORTHERN PLAINS THROUGH THURSDAY. THIS WILL ALLOW NORTHWEST FLOW TO BE PERSISTENT ON WEDNESDAY AND THURSDAY. 850MB TEMPS DURING THIS PERIOD LOOK TO BE HOVERING RIGHT AROUND -7 TO -8C AND WITH LAKE SUPERIOR TEMPS ON AVERAGE AROUND 8-9C...THERE IS PLENTY OF OVER LAKE INSTABILITY TO SUPPORT LAKE EFFECT SHOWERS. ON WEDNESDAY MORNING...EXPECT THE WINDS TO BE NW TO WNW...BEFORE A WEAK SURFACE TROUGH AND SHORTWAVE SWEEPS THROUGH WEDNESDAY EVENING AND SHIFTS THE DIRECTION TO A MORE NORTH-NORTHWESTERLY DIRECTION. WILL HAVE THE HIGHEST POPS EAST OF GRAND MARAIS OVER THE EAST AND ALONG ALL OF THE HIGHER TERRAIN OVER THE WEST FOR WEDNESDAY...THEN SHIFTING TO MORE TRADITIONAL NW-NNW FLOW LOCATIONS FOR WEDNESDAY NIGHT (EG ALGER COUNTY OVER THE EAST). WILL CONTINUE TO SHOW DEFINITE POPS FOR THE FAVORED EASTERN CWA LOCATIONS SINCE THE MODELS HAVE BEEN CONSISTENT ON THIS IDEA FOR THE LAST COUPLE OF DAYS. WILL CONTINUE THE HIGH POPS FOR THURSDAY...ALTHOUGH TEMPS MAY WARM A DEGREE. EVEN WITH THE LIKELY/DEFINITE POPS FOR WEDNESDAY...DON/T EXPECT THE INTENSITY TO BE AS STRONG AS LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT WHEN A QUICK PERIOD OF DEEPER MOISTURE WITH THE SHORTWAVE AND SURFACE TROUGH MOVES THROUGH. DEEP CLOUD LAYER (10-12KFT) AND LAKE INDUCED CAPE VALUES OF 300-500 J/KG SUPPORT THE POTENTIAL FOR STRONGER LAKE EFFECT SNOW BANDS ON WEDNESDAY NIGHT. THIS COULD EVEN END UP PRODUCING MODERATE TO HEAVY SNOWFALL IN QUICK BURSTS...SIMILAR TO WHAT WAS SEEN IN PORTIONS OF WESTERN UPPER MICHIGAN THIS AFTERNOON/EVENING (JACOBSVILLE SAW 2.6IN IN 1HR). THE MAIN LIMITING FACTORS FOR THIS EVENT WILL BE THE LOWER SNOW RATIOS AND MID-UPPER 30S NEAR SURFACE TEMPERATURES. CONTINUE TO THINK SNOW RATIOS WILL BE ON THE LOW END FOR TRADITIONAL LAKE EFFECT EVENTS...SINCE THE CLOUD LAYER WILL BE AT OR BELOW THE DGZ. THUS...WITH MUCH OF THE FORCING BELOW...WOULD EXPECT RATIOS TO BE IN THE 10-13 TO 1 RANGE INSTEAD OF THE NORMAL 17-25 TO 1. IN ADDITION...WITH UPPER 40 DEGREE WATER MODIFYING THE NEAR SURFACE AIR...LOCATIONS NEAR LAKE SUPERIOR WILL BE HOVERING IN THE MID TO EVEN UPPER 30S. THIS WILL TRY TO PUSH WETBULB ZERO VALUES UP TO 1KFT...WHICH WOULD BE ENOUGH FOR SOME MIXING OF RAIN/SNOW NEAR THE SHORELINE. IN ADDITION...THOSE WARMER SURFACE TEMPERATURES WILL ATTEMPT TO LIMIT THE SNOWFALL ACCUMULATION EXCEPT UNDER THE STRONGER BANDS...WHERE THE RATE WILL COMPENSATE FOR THE WARMER TEMPS. THEREFORE...PINNING DOWN SNOWFALL AMOUNTS WITH THE MULTIPLE FACTORS IS TRICKY FOR THIS EARLY SEASON EVENT. IN GENERAL...THINK THE SNOWFALL AMOUNTS DURING THE WEDNESDAY AFTERNOON/NIGHT PERIOD WILL BE UNDER ADVISORY CRITERIA (GENERALLY 1-3INCH) WITH SOME LOCATIONS SEEING ADVISORY AMOUNTS (3-4INCH) WHERE ANY STRONGER BANDS SETS UP. ONE OTHER ITEM TO MENTION FOR THE WEDNESDAY AFTERNOON AND NIGHT PERIOD IS THE POTENTIAL FOR SOME WATERSPOUTS OVER THE SOUTHEASTERN PART OF LAKE SUPERIOR. WITH THE CONVECTIVE CLOUD DEPTH OF 10-12KFT AND DELTA-T VALUES AROUND 16...THAT DOES PLACE THAT AREA ON THE EDGE OF THE WATERSPOUT POTENTIAL ON THE SZILAGYI WATERSPOUT NOMOGRAM. THUS...WILL PUT IN A SLIGHT CHANCE MENTION IN THAT AREA AND THEN END IN BY THURSDAY MORNING SINCE THE MOISTURE DEPTH BEGINS TO LESSEN. THE UPPER TROUGH WILL FINALLY BEGIN SHIFTING EAST ON THURSDAY NIGHT AND A HIGH PRESSURE RIDGE WILL BEGIN TO MOVE EAST INTO THE UPPER GREAT LAKES. THIS WILL BRING DRIER AIR INTO THE CWA FROM WEST TO EAST WHILE BACKING THE WINDS TO THE SOUTHWEST. THUS...EXPECT THE ONGOING LAKE EFFECT PRECIPITATION TO DIMINISH OVER THE WEST AND THEN SLOWLY DIMINISH AND SHIFT EAST OVER THE EASTERN CWA. FORTUNATELY...THE MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH THE SHORTWAVE ROUNDING THE UPPER RIDGE OVER THE WEST AND SLIDING SOUTHEAST INTO THE UPPER GREAT LAKES REGION ON FRIDAY NIGHT INTO SATURDAY. THIS CLIPPER SYSTEM (WITH THE LOW SLIDING ALONG THE EASTERN SHORE OF LAKE SUPERIOR) SHOULD PRODUCE SOME PRECIPITATION OVER THE CWA ON FRIDAY NIGHT AND HAVE THE HIGHEST POPS OVER THE NORTHEAST HALF. THEN AFTER THE COLD FRONT MOVES THROUGH...EXPECT THERE TO BE A PERIOD OF LAKE ENHANCED RAIN/SNOW IN THE NORTHWEST WIND FAVORED LOCATIONS AS 850MB TEMPS FALL BACK TO -6C. WILL HIGHLIGHT THE HIGHEST POPS IN THOSE LOCATIONS FOR SATURDAY AND THEN GRADUALLY DIMINISH THEM SATURDAY NIGHT INTO SUNDAY...AS THE UPPER TROUGH SHIFTS EAST AND HIGH PRESSURE MOVES OVER THE CWA. IT LOOKS LIKE THE SUNDAY INTO SUNDAY NIGHT PERIOD WILL GIVE A LITTLE BIT OF A REPRIVE TO THE UNSETTLED WEATHER THAT WE WILL SEE THIS WEEK. LATEST TRENDS IN THE 00Z MODEL RUNS HAVE THE UPPER TROUGH THAT WILL BE DIGGING OVER THE ROCKIES POTENTIALLY BECOMING CUTOFF OVER THE WEST COAST. AS THIS OCCURS ON MONDAY...AN ELONGATED TROUGH ASSOCIATED FROM A LOW IN THE CENTRAL PLAINS WILL SLOWLY MOVE EAST ACROSS THE AREA. THIS WILL BE SOMETHING TO KEEP AN EYE ON...AS TEMPERATURES WILL LIKELY BE COLD ENOUGH FOR SNOW ALOFT (ALTHOUGH SURFACE TEMPERATURES ARE MARGINAL) AND IT COULD PRODUCE MEASURABLE SNOW. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 119 PM EDT TUE OCT 22 2013 EXPECT MVFR WX TO DOMINATE MOST OF THIS FCST PERIOD WITH LAKE EFFECT SNOW SHOWERS. AT SAW...AS WINDS BACK TO THE WEST IN THE EVENING...THIS WILL PUSH LAKE EFFECT CLOUDS OUT AND VFR CONDITIONS WILL CONTINUE OVERNIGHT. AS WINDS PICK UP AGAIN...WEST WINDS PICK UP AGAIN AND GUSTY WINDS WILL PUSH MVFR CLOUDS BACK IN AGAIN BY MID WED MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 520 AM EDT TUE OCT 22 2013 NORTH TO NORTHWEST GALES THIS MORNING ARE EXPECTED TO DIMINISH BY AFTERNOON AS THE GRADIENT WEAKENS BEHIND A DEPARTING TROUGH. HOWEVER...WITH PERSISTENT LOW PRES TO THE EAST AND RIDGE OVER THE NORTHERN PLAINS...WINDS WILL BE LINGER IN THE 20 TO 30KT RANGE THROUGH THE THU. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...JLB LONG TERM...SRF AVIATION...07 MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
100 PM EDT TUE OCT 22 2013 .AVIATION... //DISCUSSION... THE SPREAD OF STRATOCU ACROSS THE TAF SITES HAS DROPPED BKN CIGS TO 3-5 KFT. EXPECTING VFR FOR MOST OF THE PERIOD...EXCEPT A BRIEF DROP TO MVFR OVERNIGHT IN DETROIT SITES AS A DISTURBANCE IS EXPECTED TO BRING ISOLATED SHOWERS TO THE AREA. THE CONVECTIVE ELEMENT OF THE CLOUD DECK WILL DISSIPATE TONIGHT...AROUND THE SAME TIME AN UPPER WAVE BRINGS PRECIP CHANCES TO SRN SITES. EXPECTING THE 3 NRN SITES TO CLEAR OUT AS THE CEILING LIFTS AND MORE DRY AIR WILL LEAD TO SCT VFR FOR MUCH OF WED. COLD AIR INFILTRATING THE REGION WILL LEAD ANY /UNLIKELY/ PRECIP TO BE A RASN MIX AT MBS EARLY WED. //DTW THRESHOLD THREATS... * HIGH CONFIDENCE IN CEILINGS BELOW 5000 FEET THIS AFTERNOON INTO THE OVERNIGHT PERIOD. && .PREV DISCUSSION...ISSUED 347 AM EDT TUE OCT 22 2013 SHORT TERM... TODAY AND TONIGHT CONFLUENT FLOW ALOFT THROUGH THE SOUTH FLANK OF THE UPPER LOW WILL MAINTAIN THE MID LEVEL DRY SLOT OVER THE SOUTHERN GREAT LAKES FOR MOST OF TODAY. THIS WILL KEEP THE INFLUENCE OF LAKE MICHIGAN SUBDUED ON THIS SIDE OF THE STATE, ESPECIALLY IN TERMS OF PRECIPITATION AND POSSIBLY EVEN CAUSING A DISRUPTION IN THE CLOUD FIELD. TRENDS IN LOW LEVEL RH PROFILES IN THE NAM AND RAP MODELS INDICATE DRY AIR FROM THE MIDWEST AS LOW AS 850 MB DURING THE MORNING WHICH COULD LEAD TO SOME BREAKS IN THE LAKE CLOUD PATTERN OR A TENDENCY FOR THE CLOUDS TO HUG CLOSER TO THE SHORELINE OVER SW LOWER EARLY IN THE DAY. THE LATEST SATELLITE IMAGERY SUPPORTS A GENERAL PARTLY SUNNY START TO THE DAY AND ALLOWS FOR SOME RENEWED STRATOCU FORMATION DUE TO SURFACE HEATING AND BEFORE HIGH CLOUDS INCREASE WITH THE NEXT SHORT WAVE LATE IN THE DAY. THE BREAKS OF SUNSHINE WILL HELP MAX TEMPS RECOVER INTO THE MID AND UPPER 40S. THE NEXT SHORT WAVE WILL ARRIVE OVER INDIANA FROM THE CENTRAL PLAINS BY EVENING NEARLY IN PHASE WITH THE SECONDARY SURFACE TROUGH SLIDING THROUGH THE NORTHERN GREAT LAKES. THE SURFACE TROUGH WILL MOVE THROUGH SE MICHIGAN DURING THE LATE AFTERNOON AND EVENING WHILE THE SHORT WAVE APPROACHES THE SOUTHERN MICHIGAN BORDER. THE COMBINATION OF THESE TWO FEATURES WILL GIVE INSTABILITY OVER LAKE MICHIGAN A CHANCE TO PERK UP, ALONG WITH BOUNDARY LAYER INSTABILITY DUE TO SURFACE HEATING, FOR A CHANCE OF LIGHT RAIN SHOWERS DURING THE LATE AFTERNOON. THE BEST CHANCE OF RAIN WILL BE DURING THE EVENING GENERALLY SOUTH OF THE I-69 CORRIDOR WHERE THE NORTH FLANK OF THE SHORT WAVE FORCING WILL INTERACT WITH THE SURFACE TROUGH. THIS REFLECTS A SOUTHWARD MODEL ADJUSTMENT ON TRACK OF SHORT WAVE WITH THE MID LEVEL TROWAL AXIS REMAINING SOUTH OF THE STATE LINE. MODEL DEPICTIONS OF DCVA ARE TOO WEAK TO GO WITH ANYTHING GREATER THAN A CHANCE POP BEFORE THE SYSTEM EXITS EASTWARD AFTER MIDNIGHT. MOST OF THE OVERNIGHT HOURS WILL THEN BE DOMINATED BY RENEWED LOW LEVEL COLD ADVECTION ON NW FLOW. BOTH THICKNESS FIELDS AND MODEL SOUNDINGS INDICATE PRECIPITATION POTENTIAL ENDED BY THE TIME THE BOUNDARY LAYER COOLS ENOUGH FOR SNOW, AND AS NORTHWEST FLOW CONFINES LAKE EFFECT CLOSER TO LAKE MICHIGAN. MIN TEMPS NEAR THE FREEZING MARK LOOK ON TARGET BY SUNRISE WEDNESDAY. LONG TERM... LONGWAVE TROUGHING ANCHORED BY A LARGE CLOSED LOW OVER THE GREAT LAKES WILL MAINTAIN MOIST CYCLONIC FLOW OVER THE AREA UNTIL THE DEPARTURE OF THE LOW TO THE NORTHEAST LATE IN THE WEEK. IN THE MEANTIME, NORTHWEST GRADIENT FLOW AROUND THE EASTERN FLANK OF HIGH PRESSURE BUILDING INTO THE CENTRAL CONUS WILL KEEP DAYTIME HIGHS IN THE MID TO UPPER 40S BENEATH H85 TEMPS PROGGED TO HOVER AROUND -5C. IN GENERAL, NORTHWEST FLOW WILL MINIMIZE CONCERN FOR LAKE EFFECT SHOWERS TO ADVANCE INTO THE AREA AS CONVECTIVE PLUMES OFF OF LAKE MICHIGAN WILL TEND TO BE SHUNTED TO OUR SOUTHWEST. THE EXCEPTION WILL BE WEDNESDAY WHEN THE LOW LEVEL FLOW IS PROGGED TO BACK TOWARD WESTERLY AHEAD OF AN APPROACHING SHORTWAVE. WITH THE HELP OF DIURNAL HEATING, A DEEP CONVECTIVE BOUNDARY LAYER WITH ORIGINS OVER LAKE MICHIGAN STANDS A DECENT CHANCE OF ADVECTING EAST INTO THE AREA. CHANCE POPS THEREFORE REMAIN IN PLACE FOR WED AFTERNOON, WITH THE BEST CHANCE FOR SHOWERS SOUTH OF I-69. LOW-LEVEL FLOW WILL BACK TO A LESSER DEGREE ON WED NIGHT AS A SHEARED H5 PV ANOMALY TRACKS ACROSS THE MI/OH BORDER. DYNAMIC FORCING ASSOCIATED WITH THE WAVE ITSELF WARRANTS CHANCE POPS NEAR THE OHIO BORDER, BUT POTENTIAL WILL BE LIMITED WITH THE DEEPER MOISTURE CONFINED TO THE OHIO VALLEY. MOIST CYCLONIC FLOW IN ADDITION TO CONTRIBUTIONS FROM LAKE SUPERIOR/MICHIGAN WILL ENSURE A SUBSTANTIAL BOUNDARY LAYER CONTRIBUTION TO A MOSTLY CLOUDY SKY CONDITION THAT IS FORECAST TO PERSIST THROUGH AT LEAST THURSDAY NIGHT. INHERITED FORECAST LOWS NEAR 30 FOR MOST AREAS STILL LOOK REASONABLE, BUT ANY POTENTIAL FOR CLEARING WILL BE WORTH MONITORING AS A FEW HOURS OF GOOD RADIATING WITHIN THE RESIDENT AIRMASS WOULD SEND TEMPS WELL INTO THE 20S. SHORTWAVE RIDGING IN ADVANCE OF ANOTHER HIGH-LATITUDE WAVE WILL WORK INTO THE AREA ON FRIDAY AGAINST A BACKDROP OF LARGER SCALE HEIGHT RISES OWING TO EASTWARD PROGRESSION OF THE LONGWAVE TROUGH. HIGH PRESSURE WILL BUILD INTO THE AREA AS A RESULT AND SHOULD HELP BREAK UP BOUNDARY LAYER CLOUD COVER TO SOME EXTENT, BUT HIGHS WILL AGAIN REMAIN IN THE 40S WITH THE THERMAL TROUGH PROGGED TO MAINTAIN ITS GRIP ON THE AREA. MARINE... A SECONDARY SURGE OF COLD AIR SPREADING OVER THE GREAT LAKES TODAY WILL REQUIRE GALE WARNINGS TO CONTINUE OVER NORTHERN AND CENTRAL LAKE HURON. WARNINGS HAVE BEEN ADDED FOR SAGINAW BAY AS FREQUENT GUSTS TO 35 KNOTS ARE NOW EXPECTED THERE AS THE WIND FUNNELS DOWN THE CENTER OF THE BAY. SMALL CRAFT ADVISORIES WILL HOLD ALONG THE SOUTHERN LAKE HURON NEARSHORE AREAS. THE STRONG WIND WILL KEEP WATERSPOUT POTENTIAL LOW EVEN AS INSTABILITY INCREASES OVER THE WATER TODAY WITH A BETTER CHANCE OVER THE OPEN WATERS OF LAKE HURON TONIGHT AS THE WIND DIMINISHES. WIND SPEED WILL CONTINUE TO DIMINISH TUESDAY NIGHT INTO WEDNESDAY BUT WILL REMAIN FROM THE NORTHWEST AND WEST, MAINTAINING BELOW NORMAL TEMPERATURE THROUGH THE END OF THE WEEK. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON... GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ421-LHZ422...UNTIL 8 PM TUESDAY. SMALL CRAFT ADVISORY...OUTER SAGINAW BAY...FROM 8 PM TUESDAY TO 8 AM WEDNESDAY. SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT SANILAC...UNTIL 8 AM WEDNESDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....MM SHORT TERM...BT LONG TERM....JVC MARINE.......BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
110 PM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 315 AM CDT TUE OCT 22 2013 LATEST WATER VAPOR IMAGERY AND RAP UPPER AIR ANALYSES SHOW THE UPPER LOW WHICH BROUGHT MUCH COLDER TEMPERATURES TO THE AREA BEING SHUNTED INTO EASTERN ONTARIO AS A FEW REINFORCING SHORTWAVES DROP SOUTHEAST THROUGH CENTRAL CANADA INTO THE HIGH PLAINS. THE MAIN SHORTWAVE OF INTEREST FOR THE SHORT TERM CAN BE SEEN OVER EASTERN SOUTH DAKOTA... AND IS HELPING TO GENERATE THE LIGHT PCPN SEEN ON RADAR AND SURFACE OBS OVER FAR SOUTHWEST MINNESOTA... EASTERN SOUTH DAKOTA... AND NORTHERN IOWA. MOST OF THIS ACTIVITY LOOKS LIKE IT WILL REMAIN SOUTH OF OUR AREA THIS MORNING... SO MAINLY JUST MENTIONED SOME FLURRIES OR LOW POPS WITH NO SNOWFALL ACCUMULATIONS. OTHERWISE... TODAY LOOKS BENIGN ACROSS THE FORECAST AREA... WITH SOME PEAKS OF SUN INTERSPERSED WITH LINGERING STRATOCU. WE MAINTAIN SOMEWHAT OF A 925-850MB THERMAL TROUGH OVER THE AREA TODAY... WHICH SHOULD KEEP PLENTY OF CLOUDS IN PLACE... AND LATEST 11-3.9 MICRON IMAGERY SHOWS PLENTY OF CLOUDS TO THE NORTH DROPPING SOUTH WITH TIME. HOWEVER... THERE ARE INDICATIONS THAT THE BOUNDARY LAYER FLOW WILL BECOME MORE ANTICYCLONIC THIS AFTERNOON... WHICH COULD WORK TO GENERATE SOME DECENT BREAKS IN THE CLOUD COVER. PLAYED THINGS MORE PESSIMISTICALLY FOR NOW GIVEN SATELLITE TRENDS AND FORECAST PROFILES... AND WENT WITH MOSTLY CLOUDY SKIES FOR MUCH OF THE DAY INTO TONIGHT. THE NEXT SHORTWAVE OF INTEREST WILL TAKE A VERY SIMILAR TRACK AS THIS MORNING/S... AND LOOKS TO DROP BY TO OUR SOUTHWEST VERY LATE TONIGHT INTO WEDNESDAY. AT THIS POINT... IT LOOKS LIKE ANY CHANCE FOR PCPN WILL ONCE AGAIN BE CONFINED TO THE FAR SOUTHWEST/SOUTH... AND WILL MAINLY BE ON WEDNESDAY. HOWEVER... DID INCLUDE SOME LOW POPS OVER THE SOUTHWEST FOR VERY LATE TONIGHT AS SOME ISENTROPIC LIFT AND FRONTOGENESIS START TO IMPINGE ON THE AREA. DID NOT MAKE ANY SUBSTANTIVE CHANGES TO THE GOING TEMPERATURE FORECASTS... WHICH WILL ONCE AGAIN BE QUITE A BIT BELOW NORMAL. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 315 AM CDT TUE OCT 22 2013 EARLY MORNING WATER VAPOR IMAGERY WITH 500MB HEIGHTS AND WINDS IDENTIFIED THE BROAD UPPER LEVEL RIDGE ORIENTED ALONG THE WEST COAST OF NORTH AMERICA...WITH A DEEP TROUGH OVER THE GREAT LAKES REGION. THE PV ANOMALY ASSOCIATED WITH THIS VORT MAX WILL DEVELOP A CYCLONE ALONG THE EASTERN SHORE OF JAMES BAY...AND ANOMALOUSLY COLD AIR WILL CONTINUE TO BE DRIVEN SOUTH ACROSS THE UPPER MIDWEST FOR THE NEXT COUPLE OF DAYS. MEANWHILE A TROPICAL PLUME OF MOISTURE ORIGINATING OVER SOUTHERN MEXICO WAS STREAMING NORTHEASTWARD ACROSS THE EASTERN SEABOARD. BY THURSDAY THIS SUBTROPICAL JET WILL PHASE WITH THE NORTHERN STREAM TROUGH AND BOMB OUT A SUB 960MB SURFACE CYCLONE OFF THE COAST OF NEWFOUNDLAND. THIS POWERFUL CYCLONE WILL CAUSE THE NORTHERLY WINDS CURRENTLY IN PLACE ACROSS THE REGION TO BECOME MORE WESTERLY BY THE END OF THE WEEK. FARTHER UPSTREAM SUBSIDENCE WILL LEAD LEE SIDE WARMING ON THE FOOTHILLS OF THE ROCKIES...AND THIS WARM AIR WILL MOVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY BY FRIDAY. IN FACT...THE 22.00 GEM/GFS/ECMWF ARE IN GOOD AGREEMENT THAT THE SATURDAY 00Z RAB AT MSP SHOULD MEASURE ABOVE 0C AT H850. NOT EXACTLY A HEAT WAVE...BUT SLIGHTLY MORE MILD NONE THE LESS. THIS WARM UP WILL BE SHORT LIVED AS ANOTHER SHORTWAVE DRIVING THIS LOW LEVEL WARM AIR ADVECTION WILL CAUSE A CYCLONE TO TRACK ACROSS SOUTHERN CANADA...AND DRIVE A WEAK COLD FRONT THROUGH THE REGION. THIS FRONTAL BOUNDARY WILL EVENTUALLY BECOME ORIENTED EAST/WEST...AND SET THE STAGE FOR A POTENTIALLY SIGNIFICANT STORM SYSTEM TO DEVELOP NEXT WEEK OVER THE MIDWEST. IN SUMMARY...A FEW WEAK WAVED EMBEDDED IN NORTHWEST FLOW WILL KEEP MID LEVEL CLOUDS IN TACT FOR MOST OF THIS WEEK...BUT NOTHING TO MERIT HAVING ANY POPS IN THE FORECAST. TEMPERATURES WILL MODERATE SLIGHTLY BY THE WEEKEND...BUT SHOULD STILL REMAIN BELOW CLIMATOLOGY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1250 PM CDT TUE OCT 22 2013 STRATOCU CLOUDS CONTINUE TO PLAGUE THE TAF SITES WITH CEILINGS BETWEEN UPPER-END MVFR AND MINIMAL VFR RANGES. CIGS EXPECTED TO GRADUALLY LIFT WITH COVERAGE SLOWLY BECOMING SCATTERED TO BROKEN IN THE LOWEST LAYER WHILE HIGHER CEILINGS REMAIN. STILL SOME UNCERTAINTY AS TO HOW LONG SOME OF THE LOWER LAYERS/CEILINGS WILL LINGER BUT SHORT-TERM MODELS PLUS OBSERVATION TRENDING PUTS THE LOWER CLOUDS IN PLACE THRU MUCH OF THE AFTN BEFORE LIFTING THIS EVE. MIDLVL CIGS WILL HOLD TNGT THRU TMRW IN THIS PERSISTENT NW FLOW ALOFT. NO PRECIP EXPECTED AT ANY OF THE TAF SITES...THOUGH KRWF MAY AGAIN BE SUBJECT SO SOME FLURRIES OR -SHSN BUT CHCS ARE LOW. WINDS WILL REMAIN NW IN THE 5-10 KT RANGE. KMSP...CEILINGS TO BOUNCE AROUND THE 3 KFT VFR/MVFR THRESHOLD FOR A COUPLE OF HOURS OR SO AFTER 22/18Z...BUT WILL EVENTUALLY LIFT INTO VFR BY LATE AFTN AND REMAIN AS SUCH THROUGHOUT THE REST OF THIS TAF ISSUANCE. CEILINGS WILL REMAIN ABOVE 1700 FT...SO NO SIGNIFICANT IMPACTS EXPECTED WITH ADVERTISED CEILINGS. WINDS STARTING OUT FROM 350 DIRECTION WILL BACK TO 300-320 THIS EVE THRU TMRW AFTN WITH SPEEDS IN THE 5-10 KT RANGE. /OUTLOOK FOR KMSP/ THU...VFR. NW WIND 10KT. THU NIGHT...VFR. NW WIND 10 KT BECMG W. FRI...VFR. W WIND 5-10 KT BECMG SW 15-20 KT. FRI NIGHT...MVFR CIGS PSBL LATE. SW WIND 10-20 KT BECMG W. SAT...MVFR CIGS PSBL EARLY. NW WIND 15-20 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ UPDATE... SHORT TERM... LONG TERM...JRB AVIATION...JPC
AREA FORECAST DISCUSSION
NWS BILLINGS MT
319 PM MDT TUE OCT 22 2013 .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 TODAY AND 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 && .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
NWS OMAHA/VALLEY NE
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 && .AVIATION...18Z TAFS FOR KOMA...KOFK...KLNK. CIGS ARE VARIABLE BETWEEN FL009-FL035...SO MAINLY MVFR...WITH SOME PATCHY IFR AND LOW VFR CIGS. MVFR CONDITIONS ARE EXPECTED TO MIX OUT AND CIGS WILL BECOME MORE VFR DURING THE 19Z-21Z PERIOD AND CLOUDS SHOULD SCATTER OUT THIS EVENING. NORTHWEST SURFACE WINDS WILL ALSO BE VARIABLE...WITH 8-14KT WINDS AT KOFK AND KOMA...AND STRONGER 10-18KT SUSTAINED WINDS WITH HIGHER GUSTS AT KLNK THRU 00Z. SURFACE HIGH PRESSURE WILL BUILD IN WITH DIMINISHING WINDS. A WEAK WEATHER DISTURBANCE WILL BRING INCREASING MID CLOUDS AFTER 06Z WITH A RAIN/SNOW MIX POSSIBLE AT KOFK/KOMA. FOR NOW WILL CONSIDER MENTIONING A PROB30 IN THOSE TAF WED AM. ZAPOTOCNY && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
125 PM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 425 AM CDT TUE OCT 22 2013 MAIN FORECAST CONCERNS WILL BE LIGHT SHOWERS OR SPRINKLES THIS MORNING AND TEMPERATURES. CURRENT RADAR TRENDS SHOW THAT THE SPRINKLES OR LIGHT SHOWERS HAVE MOVED INTO THE SOUTHEAST HALF OR SO OF THE FORECAST AREA EARLY THIS MORNING. SATELLITE SHOWS A FEW BREAKS IN THE CLOUDS...BUT MOSTLY CLOUDY SKIES WILL PERSIST. THE CLOUD COVER HAS HELPED TO KEEP TEMPERATURES A LITTLE ON THE WARMER SIDE. MODELS HAVE HAD SOME LIGHT SHOWERS OR SPRINKLES MOVING THROUGH THE FORECAST AREA DURING THE MORNING. THE NAM AND GFS INDICATE THAT THESE WILL CONTINUE INTO THE MORNING AND BE GONE BY MID DAY...BUT THE HRRR AND 4KM WRF ARE A LITTLE QUICKER TO MOVE THINGS THROUGH THE AREA AND INDICATE THAT THE PRECIPITATION COULD BE DONE AS EARLY AS BY SUN RISE THIS MORNING. WITH THE CURRENT LOCATION OF THE SPRINKLES ON THE RADAR AM INCLINED TO BELIEVE THE SHORT TERM MODELS AND BRING AN EARLY END TO THE PRECIPITATION. BASED ON THE MOVEMENT OF THE PRECIPITATION...THE RETURNS ON THE RADAR AND PRECIPITATION AMOUNTS AS IT MOVES OVER EXPECT THAT SPRINKLES WILL BE THE EXTENT OF THE PRECIPITATION. THE SURFACE PRESSURE GRADIENT TIGHTENS FOR A WHILE THIS MORNING AND THE WINDS AT 850MB ARE 25 TO 35 KTS DURING THE MORNING AND INTO THE AFTERNOON HOURS. EXPECT THERE TO BE BREEZY CONDITIONS DURING THE LATE MORNING INTO EARLY AFTERNOON BEFORE WINDS DIMINISH AS THE SUN GOES DOWN THIS AFTERNOON. CLOUDS WILL BE MORE PREVALENT IN THE NORTHEAST PART OF THE FORECAST AREA AND WILL KEEP TEMPERATURES ON THE LOWER SIDE WHILE A LITTLE MORE SUN AND WARMER TEMPERATURES ALOFT WILL ALLOW FOR SOME WARMER TEMPERATURES IN THE SOUTHWEST. SOME CLOUD COVER WILL CONTINUE ACROSS THE AREA THROUGH THE NIGHT TONIGHT...BUT DESPITE THE CLOUDS TEMPERATURES ACROSS THE AREA WILL BE COOLER THAN TONIGHT AS THE WIND DIMINISHES AND A FEW BREAKS IN THE CLOUDS MOVE THROUGH. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 425 AM CDT TUE OCT 22 2013 BIGGEST CHALLENGE WILL BE DETERMINING TEMPERATURES. THE LONG TERM MODELS CONTINUE TO FORECAST NORTHWEST FLOW AT THE BEGINNING OF THE LONG TERM FORECAST AS WE WILL BE SITUATED BETWEEN A BROAD SYNOPTIC LONGWAVE TROUGH TO THE EAST AND A RIDGE ALONG THE WEST COAST...WITH AN EMBEDDED CUTOFF LOW OFF THE SOUTHERN CALIFORNIA COAST. THE UPPER LEVEL PATTERN WILL BE HIGHLY AMPLIFIED TO BEGIN THE LONG TERM. THERE COULD BE JUST ENOUGH INFLUENCE LEFT FROM A SHORTWAVE TROUGH FORECAST TO GIVE US A SHOT AT SOME LIGHT PRECIPITATION IN OUR FAR NORTHEAST AS THE SHORTWAVE TROUGH DEPARTS TO THE SOUTHEAST. THIS SEEMS TO BE A NEAR COPY OF WHAT HAS HAPPENED OVERNIGHT AND INTO THIS MORNING...EXCEPT ENERGY WILL BE A BIT FARTHER TO THE EAST...LESSENING OUR CHANCES OF MUCH PRECIPITATION AND HAVE KEPT IT OUT OF THE FORECAST...ANTICIPATING THAT ANY PRECIPITATION WILL BE JUST TO THE EAST. MODELS INDICATE CONSIDERABLE HEIGHT RISES BEHIND THE COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED WAVE AND I HAVE INCREASED WIND SPEEDS ACCORDINGLY. FOR THE MOST PART...I KEPT HIGH TEMPERATURES CLOSE TO PREVIOUS FORECASTS. I HAVE LOWERED TEMPERATURES A FEW DEGREES FOR WEDNESDAY NIGHT AS SKY COVER SHOULD BE RELATIVELY SCANT AND WIND SPEEDS SLACKEN. THIS COULD BE THE FIRST HARD FREEZE FOR MANY AREAS OF THE CWA. ALSO...THURSDAY NIGHT COULD BE TRICKY FOR LOW TEMPERATURES AS RETURN FLOW COULD CAUSE TEMPERATURES TO STEADY OUT OR EVEN RISE BY OVERNIGHT...ESPECIALLY SOUTHWEST. IN FACT...OUR SOUTHWEST MAY NOT COOL THAT MUCH AT ALL AS WARM AIR ADVECTION TAKES OVER THERE FIRST. AS A RESULT...LOW TEMPERATURES HAVE BEEN RAISED IN OUR FAR SOUTHWEST TO THE MID 30S TO NEAR 40...WHILE CENTRAL AND EASTERN AREAS WILL HAVE LOWS IN THE MID TO UPPER 20S...AND AGAIN...WITH TEMPERATURES BECOME STEADY OR SLOWLY RISING BY THE OVERNIGHT HOURS. TEMPERATURES WILL BE RATHER SEASONABLE FOR THE MOST PART FOR THE REST OF THE LONG TERM. FRIDAY NIGHT LOOKS LIKE THE WARMEST BEFORE ANOTHER COOL SHOT OF AIR COMES IN WITH ANOTHER WAVE. PATTERN STILL SHOULD BECOME MORE QUASI-ZONAL BY SUNDAY...AS MODELS HAVE BEEN ADVERTISING FOR AWHILE. THIS IS A RESULT OF A MORE SIGNIFICANT SHORTWAVE TROUGH ENTERING THE PACIFIC NORTHWEST. THERE COULD BE A NOTICEABLE WARM-UP IN ADVANCE OF THIS WAVE...BUT I AM GETTING MIXED SIGNALS FROM OPERATION AND ENSEMBLE PREDICTIONS AND I FIND IT BEST TO STICK WITH THE INITIAL ALLBLEND GRIDS. THE FORECAST ESSENTIALLY STAYS DRY THROUGH MONDAY AS TIMING OF THIS WAVE STILL KEEPS IT FAR ENOUGH AWAY TO BRING IN MUCH PRECIPITATION TO OUR AREA AND A COLD FRONT SHOULD BE FAR ENOUGH EAST TO KEEP ANYTHING THAT DEVELOPS ALONG IT TO OUR EAST. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 119 PM CDT TUE OCT 22 2013 A BRISK NORTHWEST WIND WILL CONTINUE THROUGH THE AFTERNOON BUT SHOULD QUICKLY DIE DOWN AFTER SUNSET AND EVEN BECOME LIGHT AND VARIABLE WITHIN ONE TO TWO HOURS AFTER SUNSET. THE WIND WILL BECOME MORE SOUTHERLY TO SOUTHWESTERLY BY DAWN ON WEDNESDAY AND REMAIN FAIRLY LIGHT THROUGH WEDNESDAY MORNING. CLOUDS WILL BE PRESENT THROUGHOUT THE PERIOD...ALTHOUGH THE CLOUDS SHOULD BE HIGH ENOUGH TO KEEP CEILINGS VFR. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...JCB LONG TERM...HEINLEIN AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
352 PM EDT TUE OCT 22 2013 .SYNOPSIS... A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND MOVE THROUGH THE AREA ON WEDNESDAY. COOL HIGH PRESSURE WILL THEN BUILD INTO THE AREA THURSDAY. ANOTHER COLD FRONT WILL MOVE THROUGH THE AREA FRIDAY WITH HIGH PRESSURE BUILDING BACK IN FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... AS OF 335 PM TUESDAY...MID CLOUDS CONTINUE TO STREAM INTO THE REGION WITH SOME PATCHY LIGHT RAIN. PER THE 3KM HRRR AND 4KM NSSL WRF AND RAP MODELS...THE BEST CHANCE OF PRECIPITATION WILL OCCUR DURING THE LATE EVENING AND ESPECIALLY BETWEEN 06Z AND 12Z. WITH A DRY SUB-CLOUD LAYER...IT WILL TAKE AWHILE FOR THE LOWER LEVELS TO MOISTEN. QPF TOTALS WILL BE VERY LIGHT...AVERAGING ONLY A FEW HUNDREDTHS OF AN INCH. WITH MAX TEMPS REMAINING IN THE 60S TODAY...MINIMUM TEMPS WILL BE COOL TONIGHT WITH LOWS IN THE LOWER TO MIDDLE 50S OVER MOST AREAS. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... AS OF 340 PM TUESDAY...WITH THE FRONT APPROACHING DURING THE MORNING HOURS ON WEDNESDAY...WILL CONTINUE A SLIGHT CHC OF LIGHT RAINFALL MAINLY NEAR THE COAST. ONCE AGAIN...QPF TOTALS WILL BE VERY LIGHT. THE FRONT SHOULD MOVE OFFSHORE BY EARLY AFTERNOON WITH GUSTY W/WNW WINDS...WITH SKIES BECOMING MOSTLY CLEAR BY 18Z TO 20Z IN THE AFTERNOON. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... AS OF 3 PM TUE...HIGH PRES WILL BUILD IN FROM THE WEST WED NIGHT BRINGING A MUCH COOLER AND DRIER AIRMASS. CAA BRINGS LIGHT MIXING THROUGH MUCH OF THE OVERNIGHT BUT COULD SEE SOME DECOUPLING LATE SETTING UP BETTER RADIATIONAL COOLING. EXPECT LOWS TO RANGE FROM THE UPPER 30S INLAND TO AROUND 50 OBX. WINDS BACK TO THE W THU AHEAD OF MUCH STRONGER COLD FRONT AND DEEPER SHORTWAVE SET TO MOVE THROUGH ON FRI. HIGHS SHOULD BE IN THE LOWER 60S THU. LOWS THU NIGHT WILL GENERALLY BE IN THE LOW 40S TO AROUND 50 OBX. A COLD BLAST OF ARCTIC AIR WILL ARRIVE ON FRI AS STRONG BUT MOSTLY DRY COLD FRONT PUSHES THROUGH IN THE MORNING. DID ADD SLIGHT CHANCE POPS AFTER MIDNIGHT THU NIGHT INTO FRI MORNING AS MODELS SHOWING LIGHT QPF. MODEL SOUNDING SHOWING MOISTURE CONFINED TO BELOW 700MB WHILE REMAINING VERY DRY IN THE DENDRITIC GROWTH ZONE SO RAINFALL AMOUNTS WILL BE LIGHT...GENERALLY LESS THAN 0.05". ARCTIC HIGH PRES BUILDS INTO THE REGION LATE FRI THROUGH THE WEEKEND. HIGH TEMPS WILL ONLY CLIMB TO AROUND 55-60 FRI AND SAT...WHICH WILL BE ABOUT 10-15 DEGREES BELOW CLIMO. EXCELLENT RADIATIONAL COOLING CONDITIONS EXPECTED WITH CLEAR SKIES...CALM WINDS...AND VERY LOW TD VALUES WILL ALLOW TEMPS TO PLUMMET WELL DOWN INTO THE LOW TO MID 30S AWAY FROM THE COAST. WILL LIKELY SEE FROST FOR AREAS AWAY FROM THE COAST WITH THESE TEMPERATURES. A MODIFYING TREND BEGINS SUN AS HIGH TRANSLATES EASTWARD THOUGH TEMPS LOOK TO REMAIN BELOW CLIMO INTO EARLY NEXT WEEK AS BELOW AVG HEIGHTS REMAIN ACROSS THE EASTERN CONUS. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... SHORT TERM /TONIGHT AND WEDNESDAY/... AS OF 1250 PM TUESDAY...MID LEVEL OVERCAST DOMINATES THE REGION THIS AFTERNOON BUT CLOUD DECKS SHOULD LOWER LATER THIS EVENING INTO TONIGHT AS THE SUB-CLOUD LAYER MOISTENS. WILL STAY CONSERVATIVE FOR NOW AND KEEP CEILINGS AT THE MVFR LEVEL LATE TONIGHT INTO EARLY WEDNESDAY WITH SPOTTY LIGHT SHOWERS EXPECTED. SKIES SHOULD CLEAR BY LATE MORNING ON WEDNESDAY AS A STRONG COLD FRONT SURGES BY THE AREA. LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 3 PM TUE...PRED VFR CONDITIONS EXPECTED THROUGH THE PERIOD. GENERALLY LIGHT WINDS THU ALTHOUGH ANOTHER STRONG BUT MAINLY DRY COLD FRONT WILL MOVE THROUGH EARLY FRI WITH STRONG CAA BRINGING GUSTY NORTHWEST WINDS AGAIN FRI AFTERNOON. && .MARINE... SHORT TERM /TONIGHT AND WEDNESDAY/... AS OF 350 PM TUESDAY...WINDS SHOULD BE W/SW TONIGHT AND CONTINUE MAINLY AT 10 KNOTS OR LESS WITH SEAS GENERALLY 2 TO 3 FEET. STRONG APPROACHING COLD FRONT ON WEDNESDAY WILL LEAD TO SW WINDS INCREASING TO 15 TO 20 KNOTS DURING THE MORNING...THEN WITH A GOOD CAA SURGE BEHIND THE COLD FRONT...EXPECT NORTHERLY WINDS OF 15 TO 20 KNOTS WITH FREQUENT GUSTS TO 25 KNOTS. SEAS WILL RESPOND PER LOCAL NWPS MODEL...BUILDING TO 5 TO 6 FEET...ESPECIALLY OVER THE CENTRAL WATERS. GIVEN THE GUSTY WINDS AND BUILDING SEAS...HAVE INITIATED A SMALL CRAFT ADVISORY FOR ALL WATERS BEGINNING AROUND 16Z ON WEDNESDAY AND CONTINUING INTO WEDNESDAY EVENING/NIGHT. LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... AS OF 3 PM TUE...ONGOING SCA TO START THE LONG TERM WITH STRONG HIGH PRES BUILDS IN FROM THE WEST BRINGING FREQUENT GUSTS TO 25KT ACROSS ALL WATERS/SOUNDS AND SEAS UP TO 6 FT ACROSS THE OUTER PORTIONS OF THE WATERS. GRADIENTS QUICKLY RELAX THROUGH THE OVERNIGHT WITH WINDS/SEAS EXPECTED TO DROP BELOW SCA CRITERIA ALL WATERS BY 10Z. ANOTHER STRONG COLD FRONT WILL MOVE THROUGH THE WATERS EARLY FRIDAY WITH SCA CONDITIONS ONCE AGAIN POSSIBLE WITH STRONG CAA. EXPECT NNW WINDS TO INCREASE TO 15-25KT AND SEAS TO BUILD TO 3-6FT...HIGHEST NORTH OF OCRACOKE. WEEKEND SHOULD FEATURE LIGHTER WINDS...AOB 15KT...AS CANADIAN HIGH PRES BUILDS OVER THE AREA. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO MIDNIGHT EDT WEDNESDAY NIGHT FOR AMZ130-135-156-158. SMALL CRAFT ADVISORY FROM NOON WEDNESDAY TO 6 AM EDT THURSDAY FOR AMZ150-152-154. && $$ SYNOPSIS...CTC NEAR TERM...CTC SHORT TERM...CTC LONG TERM...SK AVIATION...CTC/SK MARINE...CTC/SK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1233 PM CDT TUE OCT 22 2013 .UPDATE... ISSUED AT 1233 PM CDT TUE OCT 22 2013 RADAR RETURNS AND FLURRIES ARE NOW OCCURRING ACROSS THE NORTHERN RED RIVER VALLEY...AND WILL EXPAND THE FLURRY MENTION EVEN FURTHER WEST. IN FACT...THE RAP SHOWS POSSIBLE FLURRIES ACROSS MUCH OF THE REGION THROUGH THE OVERNIGHT HOURS...AND ADJUSTED ACCORDINGLY. LAKE EFFECT SNOW HAS NEVER MATERIALIZED (WINDS TOO WEAK)...AND REMOVED THE SCATTERED SNOW SHOWERS. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 335 AM CDT TUE OCT 22 2013 500 MB UPPER LOW OVER EASTERN LAKE SUPERIOR. STILL HAVE NORTHERLY FLOW OVER THE AREA BUT WITH WEAK HIGH OVER WESTERN MANITOBA SFC FLOW IS WEAK AND WITH INVERSION AT 850 MB AND SOME TRAPPED MOISTURE BELOW THAT CLOUDS WILL BE THE GENERAL RULE THROUGH WEDNESDAY. SOME BREAKS HERE AND THERE THOUGH. SFC FLOW AROUND LAKE OF THE WOODS HAVE NOT BE CONDUCIVE FOR ANY LAKE EFFECT SNOW SHOWERS AS WINDS HAVE BEEN CALM OR VARIABLE UNDER 5 KTS. NOT SURE ANY CHANGE TODAY...BUT DID KEEP LOW POPS FOR SCT SNOW SHOWERS AROUND THIS AREA TODAY AS SNOW SHOWERS ARE EVIDENT ON SOUTH END OF LAKE WINNIPEG OFF CANADIAN RADAR. NO ECHOES SHOWING UP ON DRYDEN ONT RADAR NEAREST TO LAKE OF THE WOODS REGION. OTHERWISE...OTHER THAN THE CLOUDS...NEXT CLIPPER TYPE SYSTEM ENTERING CNTRL ALBERTA WILL TRACK RATHER SIMILAR TO THIS PAST ONE BUT APPEARS PRETTY WEAK. PREV FCST SEEMED A BIT TOO FAR EAST WITH PRECIP TONIGHT INTO WED SO TRIMMED BACK A BIT AND EVEN THEN MOST 00Z MODELS KEEP ANY REAL -SN WEST OF OUR FCST AREA. 850 MB TEMPS CHANGE LITTLE...SO EXPECT ABOUT THE SAME TEMPS FOR HIGHS TODAY AND WED AS ON MONDAY...BUT DUE TO WARMER START WITH CLOUDS MAYBE A DEGREE OR TWO WARMER THAN ON MONDAY. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 335 AM CDT TUE OCT 22 2013 UPPER LOW WILL MOVE EAST AND THEN NORTHEAST THRU QUEBEC AND 500 MB FLOW WILL FLATTEN OVER THE NRN PLAINS/SRN CANADIAN PRAIRIES. 850 MB WARM ADV WILL SPREAD EAST THRU THE RRV WED NIGHT INTO NW MN THURSDAY. WILL HAVE SOME FLURRIES MENTIONED WITH THIS AS ALL MODELS PAINT SOME VERY LOW QPF. FOR FRIDAY THROUGH MONDAY...LONG WAVE UPPER AIR PATTERN DOES NOT CHANGE MUCH THIS PERIOD. LONG WAVE UPPER LEVEL RIDGE REMAINS OVER WESTERN NORTH AMERICA AND AN UPPER LEVEL TROUGH REMAINS OVER EASTERN NORTH AMERICA. EASTERN LONG WAVE TROUGH DOES WEAKEN A BIT THROUGH THE PERIOD HOWEVER WESTERN RIDGE MAINTAINS ITS INTENSITY. THE GFS AND ECMWF WERE IN REASONABLE AGREEMENT AT 84 HOURS WITH THE GFS SLIGHTLY FASTER. UPPER AIR PATTERN SPLITS BY THE END OF THE PERIOD WITH THE ECMWF FASTER THAN THE GFS WITH THE NORTHERN FLOW AND THE GFS FASTER THAN THE ECMWF WITH THE SOUTHERN FLOW. WILL BLEND THE GFS AND ECMWF. WILL TRIM BACK LOW POPS IN THE FAR NORTHEAST ZONES FRI...SUN AND TUE. LITTLE CHANGE TO TEMPS FROM YESTERDAYS RUN. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1233 PM CDT TUE OCT 22 2013 KIND OF A PERSISTENCE FORECAST THIS TIME AROUND. NOT A HIGH CONFIDENCE FORECAST IN TERMS OF NAILING CEILING HEIGHTS BUT PRETTY CONFIDENT IN KEEPING SOME SORT OF CEILINGS AROUND. THERE HAS BEEN A LOT OF BOUNCING AROUND IN CEILING HEIGHTS THIS MORNING AND AM TRYING NOT TO CHASE TOO MUCH. WILL GO PREDOMINANT MVFR BUT COULD SEE BOUNCING BETWEEN VFR AND IFR. HAVE SEEN SOME LOWER VSBYS DUE TO LIGHT SNOW SHOWERS BUT WILL NOT MENTION ANY AT THIS POINT DUE TO LOW PROBABILITY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ UPDATE...TG SHORT TERM...RIDDLE LONG TERM...HOPPES/RIDDLE AVIATION...GODON
AREA FORECAST DISCUSSION
NWS PORTLAND OR
226 PM PDT TUE OCT 22 2013 .SYNOPSIS...STRONG BLOCKING HIGH PRESSURE RIDGE ALOFT WILL CONTINUE TO BE THE DOMINANT FEATURE FOR THE NEXT FEW DAYS...WHICH WILL MAINTAIN STRONG VALLEY INVERSIONS. AN UPPER LOW TRAPPED WITHIN THE RIDGE DRIFTS TO VANCOUVER ISLAND BY THU AFTERNOON AND THEN REMAINS NEARLY STATIONARY UNTIL SAT. OFFSHORE LOW-LEVEL FLOW WEAKENS TONIGHT AND WED. LONGER RANGE MODELS ARE HINTING AT A CHANGE TO A COOLER REGIME LATE IN THE WEEKEND AND EARLY NEXT WEEK. && .SHORT TERM...TONIGHT THROUGH FRIDAY... THE LARGE-SCALE PATTERN REMAINS UNCHANGED...WITH A STRONG UPPER LEVEL RIDGE CENTERED ALONG THE BRITISH COLUMBIA COAST THROUGH ABOUT KAST AND ALONG THE CASCADES. WATER VAPOR IMAGERY SHOWS A TRAPPED UPPER LOW AT 43N 130W. THE LARGE-SCALE FEATURES WILL SHOW VERY LITTLE CHANGE THROUGH THU. THE MAIN CHANGE WILL BE THE TRAPPED LOW. MODELS SHOW IT DRIFTING TO VANCOUVER ISLAND BY 18Z THU. THE BIGGER CHANGES WILL OCCUR ON THE SMALLER SCALE. STRATUS SURGE HAS WORKED ITS WAY TO THE S WA COAST AS OF 20Z...BUT NOT ENOUGH INLAND PENETRATION TO REACH KTMK. KAST WEBCAMS SHOWING SOME LOW STRATUS JUST TO THE WEST JUST BEFORE 20Z. 12Z NAM12 MODEL DOES NOT SEEM TO HAVE A GOOD FEEL FOR THIS LOW-LEVEL MOISTURE...AT LEAST LOOKING AT THE 975MB LEVEL. OBVIOUSLY THIS MOISTURE IS BELOW 975MB.THE 17Z HRRR 2M RH FIELD SEEMS TO HAVE A PRETTY DECENT HANDLE ON THE STRATUS. IT SHOWS THE LOW CLOUDS ALONG THE BEACHES PUNCHING INTO THE MAJOR COASTAL RIVER DRAINAGES AROUND SUNSET. THE OTHER SMALL-SCALE FEATURE OF NOTE IS THE OFFSHORE FLOW. THE KTTD-KDLS GRADIENT WAS AROUND -5.5 MB LATE THIS MORNING. 20Z SEA-LEVEL PRESSURE READING AT KDLS NOT AVAILABLE DUE TO MAINTENANCE ON THE SENSOR(S). THE 20Z KPDX-KTTD GRADIENT WAS 1.0 MB...WHICH IS TYPICALLY TOO HIGH FOR EAST WIND TO SURFACE AT KPDX. CROWN POINT WIND SENSOR STILL GUSTING TO 45 MPH. NAM MAINTAINS THIS OFFSHORE FLOW TONIGHT...THEN WEAKENS IT WED. THE COMBINATION OF INVERSIONS AND THE LOW-LEVEL OFFSHORE FLOW WILL MAKE INLAND TEMPERATURE FORECASTING SOMEWHAT TRICKY. CASCADES AND HIGHER ELEVATIONS OF THE COAST RANGE WILL REMAIN BALMY...EVEN AT NIGHT. TEMPERATURES IN VALLEYS...LOWEST CASCADE FOOTHILLS...AND AREAS AT THE WEST END OF THE GORGE WILL BE MOST TRICKY. EXPECT THE STRATUS TO PERSIST ALONG THE COAST AT LEAST WED AND THU. LEFT IN THE MENTION OF THE POSSIBILITY OF DRIZZLE LATE TONIGHT... ALTHOUGH IT SEEMS THE BETTER CHANCE MIGHT BE WED NIGHT IF THE MARINE LAYER CONTINUES TO DEEPEN. A MUDDLED SYNOPTIC PATTERN DEVELOPS THU NIGHT AND FRI. THE STRAY CUT-OFF LOW CONTINUES TO HANG OUT AROUND VANCOUVER ISLAND...WHILE A MUCH STRONGER LOW REACHES 37N 132W...WITH STRONG HIGH PRESSURE ALOFT OVER THE PAC NW. FLAT SURFACE GRADIENTS THU NIGHT AND FRI WILL HELP TO STRENGTHEN THE INVERSIONS AND ALLOW VALLEY FOG AND STRATUS COVERAGE TO INCREASE. WEISHAAR .LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...EXPECT DRY AND MILD CONDITIONS TO PREVAIL THROUGH THE WEEKEND AS HIGH PRESSURE REMAINS IN CONTROL. NIGHT TIME FOG FORMATION WILL BE THE PRIMARY ISSUE FOR THE AREA THROUGH THE EXTENDED PERIOD. LATE SUNDAY THE UPPER FLOW BECOMES AMPLIFIED AND MERIDIONAL AS A SHORTWAVE DIGS SOUTH TOWARD THE GREAT BASIN FROM ALBERTA. AT THIS TIME IT DOES NOT APPEAR THAT ANY MOISTURE WILL MAKE IT INTO OUR AREA FROM THIS LOW...HOWEVER THE POTENTIAL IS THERE FOR AN IMPACT ON TEMPERATURES. HOW MUCH OF AN IMPACT WILL DEPEND ON HOW CLOSE THIS WAVE GETS TO THE COLUMBIA RIVER GORGE. IF IT PROGRESSES CLOSER THAN CURRENT MODELS DEPICT...THEN EASTERLY WINDS THROUGH THE GORGE WILL BE STRONGER AND TEMPERATURES COOLER THAN CURRENTLY FORECAST. HIGH PRESSURE ALOFT RETURNS TUESDAY. BURGESS && .AVIATION...MOSTLY VFR CONDITIONS PREVAIL THROUGH ABOUT 00Z THIS EVENING. THE CENTRAL OREGON COAST WILL REMAIN UNDER IFR/LIFR LOW MARINE CLOUDS...BUT MAY BRIEFLY LIFT TO MVFR FROM 21Z-00Z. OTHERWISE...OFFSHORE FLOW WEAKENS TONIGHT WHICH WILL ALLOW MORE EXTENSIVE LIFR LOW CLOUDS/FOG TO DEVELOP ALONG THE COAST AND INLAND AFTER 06Z. KPDX AND APPROACHES...VFR THROUGH 06Z. MARINE STRATUS WILL PUSH ALONG THE COLUMBIA RIVER TONIGHT AS OFFSHORE FLOW WEAKENS... BRINGING IFR/LIFR STRATUS/FOG AFTER 08Z. /27 && .MARINE...LITTLE CHANGE FOR THE MARINE ENVIRONMENT FOR THIS WEEK. RATHER TRANQUIL WEATHER PREVAILS...WITH WINDS 15 KT OR LESS. SEAS RUNNING 6 TO 7 FT THROUGH THIS EVENING...BUT WILL SUBSIDE BACK TO 3 TO 5 FT ON WED...AND HOLD AT THAT RANGE THROUGH FRI. ROCKEY. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...NONE. WA...NONE. 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 SIOUX FALLS SD
119 PM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 422 AM CDT TUE OCT 22 2013 CLIPPER SYSTEM MOVING ACROSS THE AREA THIS MORNING. LOOKS LIKE ENOUGH UPPER LEVEL ENERGY HANGS AROUND TO KEEP THE PRECIPITATION GOING A BIT LONGER THIS MORNING THAN PREVIOUSLY FORECAST. NAM...HRRR AND RAP ALL SUGGEST LIGHT PRECIPITATION WILL LINGER THROUGH 15Z IN SIOUX FALLS AND 17Z OR SO ACROSS PORTIONS OF NORTHWEST IOWA. WOULD EXPECT THIS TO BE PREDOMINATELY LIGHT SNOW ALONG AND NORTHEAST OF A HURON TO SIOUX FALLS TO SPENCER IOWA LINE...WITH A FEW SNOWFLAKES EVEN POTENTIALLY MIXING IN AS FAR SOUTH AS AREAS JUST NORTH OF THE MISSOURI RIVER. THE AFTERNOON HOURS WILL BE DRY...WITH SKIES BECOMING PARTLY SUNNY. EXPECTING GOOD MIXING AGAIN...AND BASED ON HOW WARM WE WERE ABLE TO GET YESTERDAY...WENT AHEAD AND BUMPED HIGHS UP A FEW DEGREES FOR TODAY...MAINLY LOW AND MID 40S. ANOTHER CLIPPER SYSTEM WILL DROP SOUTHEAST TOWARDS THE AREA LATER TONIGHT INTO WEDNESDAY. TEMPERATURES TONIGHT ARE TRICKY. WITH CALM WINDS LOCATIONS IN THE EAST SHOULD DROP RAPIDLY IN THE EVENING HOURS. MEANWHILE AS CLOUDS INCREASE FROM WEST TO EAST TEMPERATURES WILL BEGIN TO RISE. TRIED TO SHOW THIS IN THE GRIDS...BUT WOULD NOT BE SURPRISED IF LOCATIONS EATS OF INTERSTATE 29 END UP A BIT COLDER THAN CURRENTLY FORECAST. THE CLIPPER SYSTEM ITSELF SEEMS TO BE TRENDING SOUTHWEST. FOLLOWING A CONSENSUS OF THE NAM...GFS...ECMWF AND HI RES MODELS SEEMS LIKE A GOOD CALL AT THIS POINT. OVERALL WOULD THINK THE OVERALL EVOLUTION WILL BE SIMILAR TO WHAT HAPPENED WITH THE CURRENT SYSTEM...A BROAD AREA OF LIGHT PRECIP AND A EMBEDDED BAND OF HIGHER QPF ASSOCIATED WITH MID LEVEL FRONTOGENESIS. 500 TO 300 MB Q VECTOR CONVERGENCE A BIT STRONGER WITH THE SYSTEM TONIGHT...LIKELY OWING TO A STRONGER UPPER JET. SO WOULD NOT BE SURPRISED IF QPF AMOUNTS END UP A BIT HIGHER OVERALL. PRECIPITATION TYPE IS AGAIN AN ISSUE. LOOKS PRETTY SIMILAR TO THIS MORNINGS EVENT IN THAT AN AREA OF SNOW WILL BE LIKELY ON THE NORTHERN EDGE OF THE BAND. BOUNDARY LAYER IS A BIT WARMER...SUGGESTING THE AREA THAT SEES MAINLY SNOW WILL PROBABLY BE PRETTY SMALL. AGAIN ONLY THINKING WE SEE A COATING TO AN INCH OF ACCUMULATION. WOULD THINK ANYWHERE ALONG AND NORTHEAST OF A HURON TO SIOUX FALLS TO SIOUX CITY LINE WOULD SEE THE BEST CHANCE OF THIS LIGHT ACCUMULATION. WILL CONTINUE TO MONITOR TRENDS...AS IF THINGS WORKS OUT JUST RIGHT...COULD SEE A NARROW AREA OF 1 TO 2 INCHES OF SNOW...BUT GIVEN THE MARGINAL THERMAL PROFILE AND QPF PLACEMENT UNCERTAINTY...CONFIDENCE REMAINS LOW. STILL SOME TIMING DIFFERENCES AS WELL...BUT GENERALLY LOOKS LIKE THE PRECIP WILL ENTER OUR WEST AROUND 08Z AND APPROACH INTERSTATE 29 AROUND 11Z. PRECIP WILL EXIT BY LATE MORNING OR EARLY AFTERNOON. SKIES WILL REMAIN MOSTLY CLOUDY THROUGH THE AFTERNOON...WITH ANOTHER DAY OF HIGHS ONLY IN THE 40S. .LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY) ISSUED AT 422 AM CDT TUE OCT 22 2013 LESS ACTIVE PATTERN RETURNS TO THE AREA WEDNESDAY NIGHT AS WAVE EXITS TO THE SOUTHEAST. STILL IN COOL NORTHWEST FLOW INTO THURSDAY...SO WELL BELOW NORMAL TEMPERATURES WILL STICK AROUND FOR ONE MORE DAY. ANTICIPATE FAIR AMOUNT OF HEATING-DRIVEN CUMULUS IN OUR NORTHEAST THURSDAY AFTERNOON BASED ON FORECAST SOUNDINGS...WITH SOME MODELS SQUEEZING OUT A FEW SPRINKLES. HAVE NOT INCLUDED ANY PRECIP MENTION AT THIS TIME...BUT EVEN IF THEY DO OCCUR...SHOULD BE SPOTTY AND VERY LIGHT. NORTHWEST WINDS BECOMING GUSTY WITH THE GOOD MIXING AS WELL... WITH BOTH CLOUDS AND WIND DIMINISHING IN THE EVENING AS SURFACE RIDGE PUSHES INTO THE CWA FROM THE WEST. TEMPERATURES WEDNESDAY NIGHT AND THURSDAY NIGHT LIKELY TO BE IN THE MID-UPPER 20S MOST AREAS...WITH HIGHS THURSDAY AGAIN IN THE 40S. LONGER RANGE FRIDAY THROUGH MONDAY FEATURES WESTERN CONUS RIDGE NUDGING EASTWARD THROUGH THE WEEKEND. STRONG WARMING ALOFT ON FRIDAY NOT LIKELY TO BE FULLY REALIZED AT THE SURFACE...THOUGH MOST AREAS SHOULD AT LEAST WARM BACK INTO THE 50S...WITH SOME LOWER 60S NOT OUT OF THE QUESTION IN OUR SOUTHWEST. UPPER WAVE DROPPING FROM CENTRAL CANADA INTO THE WESTERN GREAT LAKES FRIDAY NIGHT/SATURDAY WILL DRAG A COOL FRONT SOUTHEAST THROUGH THE NORTHERN PLAINS. MODELS NOW TRENDING BACK TOWARD HOLDING THE COLDEST OF AIR WITH THIS SYSTEM NORTHEAST OF OUR AREA...THOUGH WILL LIKELY STILL SEE HIGHS SATURDAY KNOCKED BACK A FEW DEGREES FROM FRIDAYS READINGS...UPPER 40S IN SOUTHWEST MINNESOTA TO MID 50S IN OUR SOUTHWEST. ANOTHER PUSH OF WARMER AIR ALOFT SHOULD HELP HIGHS SUNDAY CLIMB BACK INTO THE 50S TO MAYBE LOWER 60S. THIS AHEAD OF STRONGER WAVE SLATED TO AFFECT THE REGION EARLY NEXT WEEK. MODELS DIFFERING ON TIMING SLIGHTLY...WITH GFS FASTER/COOLER THAN ECMWF BY LATE MONDAY...THOUGH BOTH MODELS CURRENTLY HOLD OFF BETTER PRECIP CHANCE FOR MOST OF OUR AREA UNTIL MONDAY NIGHT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 116 PM CDT TUE OCT 22 2013 CEILINGS WILL CONTINUE TO IMPROVE THROUGH THE AFTERNOON HOURS SETTLING IN ON THE LOW END SIDE OF VFR. CONDITIONS ARE EXPECTED TO BECOME PARTLY CLOUDY THIS EVENING...WITH CEILINGS LOWERING INTO THE MVFR RANGE OVERNIGHT AS ANOTHER FAST MOVING WAVE MOVES THROUGH THE AREA. APPEARS AS THOUGH THERE IS A LIMITED AMOUNT OF ICE PRODUCTION IN THE CLOUDS...WHICH SHOULD LIMIT SNOW FALL AMOUNTS AND REDUCTIONS TO VISIBILITY. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...CHENARD LONG TERM...JH AVIATION...
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1222 PM CDT TUE OCT 22 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 340 AM CDT TUE OCT 22 2013 AT 3 AM...A BAND OF LIGHT RAIN AND SNOW EXTENDED FROM CENTRAL IOWA NORTHWEST TO SOUTHEAST SOUTH DAKOTA. THIS PRECIPITATION IS LOCATED IN AN AREA OF 900 TO 700 MB FRONTOGENESIS THAT HAS DEVELOP AHEAD OF A SHORT WAVE TROUGH LOCATED OVER EASTERN SOUTH DAKOTA. THE MESO MODELS SUGGEST THAT THIS FORCING ALONG WITH THE 280-290K ISENTROPIC LIFT WILL REMAIN JUST SOUTH AND WEST OF THE FORECAST AREA. IN ADDITION WITH THE 280-290K CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN 20 AND 50 MB...THERE MAY BE SOME SATURATION ISSUES IN NORTHEAST IOWA. RAP BUFKIT SOUNDINGS SHOW THAT THERE WILL BE A VERY BRIEF PERIOD WHERE THE OMEGA WILL INTERSECT THE DENDRITIC GROWTH ZONE...BUT ALSO AT THIS TIME THERE IS STILL QUITE A BIT OF DRY AIR BELOW 800 MB. IT DEFINITELY LOOKS BETTER AS ONE HEADS SOUTH TO WATERLOO IOWA. DUE TO THIS...KEPT A 20 TO 40 PERCENT CHANCE OF RAIN AND SNOW BORDERING THE DES MOINES AND DAVENPORT COUNTY WARNING AREAS BETWEEN 22.10Z AND 22.20Z. THESE TIMES WERE BASED ON THE MESO MODELS. LIQUID AMOUNTS WILL BE LESS THAN A TENTH OF AN INCH AND SNOW AMOUNTS WILL BE LESS THAN A HALF INCH SOUTH OF A ST ANSGAR IOWA TO PLATTEVILLE WISCONSIN. FOR THIS EVENING...THE MODELS CONTINUE TO SHOW STEEP /7 TO 7.5 C/KM/ SURFACE TO 700 MB LAPSE RATES ACROSS THE FORECAST AREA. THIS WILL LIKELY KEEP SOME MID CLOUDS ACROSS THE FORECAST AREA. .LONG TERM...(WEDNESDAY THROUGH MONDAY) ISSUED AT 340 AM CDT TUE OCT 22 2013 ON WEDNESDAY...THE 22.00Z MODELS SHOW THAT ANOTHER SHORT WAVE TROUGH WILL MOVE SOUTHEAST ACROSS WESTERN AND SOUTHERN IOWA. AS A RESULT...MUCH OF THE FRONTOGENETIC FORCING AND 280-290K ISENTROPIC LIFT STAY WELL WEST AND SOUTH OF THE FORECAST AREA. WITH NOT MUCH LIFT AND 280-290K CONDENSATION PRESSURE DEFICITS RUNNING BETWEEN 30 AND 50 MB... TOOK OUT THE PRECIPITATION CHANCES OUT OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN. LIKE THE 21.12Z MODELS...THE 22.00Z MODELS ARE CONTINUING TO TREND THAT THAT THE WESTERN PERIPHERY OF THE LONG WAVE TROUGH OVER EASTERN CANADA WILL SHIFT A BIT FURTHER EAST AND THIS WILL SHIFT THE STORM TRACK INTO THE MINNESOTA ARROWHEAD AND EASTERN WISCONSIN. AS RESULT...IT DOES NOT LOOK LIKE WE WILL SEE ANOTHER SURGE OF COLD INTO THE REGION FOR THE WEEKEND. THIS WILL ALLOW TEMPERATURES TO WARM CLOSER TO NORMAL. IN ADDITION...PRECIPITATION CHANCES LOOK TO MAINLY TO OUR NORTH AND EAST. HOWEVER CANNOT COMPLETELY TAKE OUT THE PRECIPITATION CHANCES ACROSS NORTH CENTRAL WISCONSIN...SO KEPT A 20 PERCENT CHANCE OF RAIN AND SNOW IN TAYLOR COUNTY FOR FRIDAY NIGHT INTO SATURDAY. LOOKING AHEAD TO EARLY NEXT WEEK...THE MODELS ARE NOW SHOWING THAT THE WESTERN RIDGE WILL RETROGRADE WEST AND THAT A LONG WAVE TROUGH WILL DEVELOP OVER THE INTER MOUNTAIN REGION. AS THIS OCCURS... THE UPPER LEVEL WINDS WILL SHIFT TO THE WEST AND SOUTHWEST. THIS WILL ALLOW EVEN WARMER AIR AIR TO MOVE BACK INTO THE AREA. THIS COULD BE OUR FIRST TASTE OF INDIAN SUMMER. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON) ISSUED AT 1222 PM CDT TUE OCT 22 2013 DEEP...COLD CYCLONIC NORTHWEST FLOW WILL REMAIN OVER THE AREA THROUGH MUCH OF THE WEEK. THE LOWER LEVEL NORTH AND NORTHWEST FLOW IN THIS PATTERN WILL PULL INCREASING LOWER LEVEL MOISTURE SOUTHWARD AND ACROSS THE TAF SITES FOR THIS AFTERNOON INTO WED. CIGS UPSTREAM ARE MVFR IN THE 1500-2500 FT RANGE. WITH DIURNAL WARMING/MIXING THIS AFTERNOON...THESE CIGS EXPECTED TO LIFT INTO THE 3000-3500 FT RANGE BY LATE IN THE DAY. STEEPER LAPSE RATES AND MDT NORTHWEST WINDS IN THE 925-800MB RANGE TONIGHT SHOULD KEEP CIGS IN THE 3000-3500FT RANGE OVERNIGHT. MODEL SOUNDINGS AND RH PROGS ALSO INDICATE STRATO- CU CIGS TONIGHT SHOULD MAINLY BE VFR. LOWER LEVEL MOISTURE INCREASES EVEN MORE FOR WED BUT MODEL SOUNDINGS CONTINUE TO SHOW STEEP LOW LEVEL LAPSE RATES AND DEEPER MIXING TO KEEP CIGS MAINLY VFR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM....BOYNE AVIATION.....RRS