Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/14/13


AREA FORECAST DISCUSSION
NWS TAUNTON MA
722 PM EDT SUN OCT 13 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER NEW ENGLAND THROUGH THE FIRST PART OF THE WEEK. LOW PRESSURE AND ITS ATTENDING COLD FRONT WILL BRING A CHANCE OF SHOWERS LATE WEDNESDAY INTO THURSDAY...THEN DRIER CONDITIONS WILL FOLLOW FOR FRIDAY INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 7 PM UPDATE... BAND OF STRATOCU CONTINUES TO SLOWLY ERODE AND SHIFT FURTHER INLAND WITH TIME. LATEST RAP GUIDANCE SEEMS TO BE HANDLING THE BAND RATHER WELL SO ADJUSTED SKIES TOWARD ITS TIMING...WHICH SUGGESTS IT MAY TAKE UNTIL ABOUT 04Z TO FULLY DISSIPATE AND MOVE OUT. OTHERWISE...FORECAST ON TRACK. WILL CONTINUE CURRENT FROST ADVISORY AS CLEARING HAS ALREADY OCCURRED FOR THE MOST PART AND LATEST GUIDANCE STILL SUGGESTS TEMPS IN THE LOW-MID 30S IN THE ADVISORY AREA. PREVIOUS DISCUSSION... CLOUDINESS REMAINS ENTRENCHED ACROSS SOUTHERN NEW ENGLAND THIS AFTERNOON BUT HAS BEGUN TO ERODE AROUND EDGES...ESPECIALLY ALONG EASTERN MA COAST WHERE LOWER LEVEL DRY AIR AND SUBSIDENCE WERE WORKING IN. EXPECT THIS TREND TO CONTINUE THROUGH THIS EVENING... RESULTING IN MOSTLY CLEAR SKIES. HOWEVER THERE IS AN OUTSIDE CHANCE WE NEVER ENTIRELY LOSE THIS CLOUD COVER ALONG MANCHESTER/ WORCESTER/WILLIMANTIC CORRIDOR SHOULD IT BECOME TRAPPED BENEATH SUBSIDENCE INVERSION. THAT MAY COMPLICATE FORECAST FOR TONIGHT. ASSUMING SKIES CLEAR... LIGHT WINDS WILL ALLOW FOR GOOD RADIATIONAL COOLING WHICH WILL DROP TEMPERATURES DOWN INTO MID 30S ACROSS PARTS OF SW NH AND NORTHERN MA...WITH AREAS OF FROST IN THESE LOCATIONS WHERE FROST ADVISORY IS POSTED. WE SHOULD ALSO SEE AREAS OF FOG/LOW CLOUDS IN RIVER VALLEYS MUCH LIKE WE HAVE SEEN PAST COUPLE OF NIGHTS. IF CLOUDS HOLD TOUGH...FROST/FOG POTENTIAL IS MUCH LOWER. SINCE CONFIDENCE IS NOT OVERLY HIGH ON SKY COVER FORECAST....WILL LEAVE FROST HEADLINES AS IS AND NOT EXPAND TO OTHER AREAS AT THIS TIME. FORECAST LOWS ARE BLEND OF BIAS-CORRECTED GFS/NAM MOS...LOWER 40S COAST/URBAN AREAS AND MID TO UPPER 30S ELSEWHERE. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... HIGH PRESSURE REMAINS OVER REGION MON. ANY FOG/LOW CLOUDS SHOULD BURN OFF QUICKLY AND WITH MORE OF SE FLOW /AS OPPOSED TO NE/ WE SHOULD NOT SEE AS MUCH DIURNAL CLOUDINESS AS WE DID TODAY. WEAK GRADIENT WILL ALLOW FOR AFTERNOON SEA BREEZES. WEAK FRONT PUSHES INTO NEW ENGLAND MON NIGHT...BUT BEST DYNAMICS REMAIN WELL TO OUR N AS IT RUNS INTO SURFACE HIGH WHICH RETREATS JUST OFFSHORE. AS A RESULT WE SHOULD SEE AN INCREASE IN CLOUDINESS BUT LITTLE MORE THAN THAT. CONTINUED TO USE BLEND OF BIAS-CORRECTED GFS/NAM MOS FOR HIGHS MON /60S/ AND LOWS MON NIGHT /40S TO LOWER 50S/. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGHLIGHTS... * MILD TEMPERATURES THROUGH THE WEEK * RISK OF SHOWERS WED NIGHT INTO FRI * MOSTLY DRY WX NEXT WEEKEND OVERVIEW AND MODEL PREFERENCES... 13/12Z MODEL GUIDANCE SUITE CONTINUES TO GRADUALLY CONVERGE ON OVERALL PATTERN THROUGH THE WEEK AHEAD. HOWEVER THERE ARE ISSUES REGARDING THE DEVELOPMENT OF A HIGHLY AMPLIFIED PATTERN ACROSS THE WESTERN CONUS AND EASTERN PACIFIC WHICH ARE CAUSING TIMING/SPATIAL DIFFERENCES IN THE DAY TO DAY SENSIBLE WX ACROSS THE E. THERE IS ENOUGH GENERAL AGREEMENT...EVEN NOW WITH A SECONDARY FRONTAL WAVE ON FRI...THAT A GENERAL ECMWF/GFS BLEND SHOULD BE A GOOD STARTING POINT FOR THIS FORECAST...WITH SLIGHT ADJUSTMENTS AS NEEDED THROUGHOUT. RIDGE OF HIGH PRES WILL GRADUALLY MOVE OFFSHORE OVER THE NEXT 48 HOUR ALLOWING A PROGRESSIVELY OPENING LONGWAVE TROF OVER THE NRN PLAINS TO SHIFT NE...BECOMING GENERALLY AN OPEN LONGWAVE TROF ACROSS ERN CANADA. INITIALLY THE DRY WX CONTINUES AS THE RIDGE REMAINS IN CONTROL. HOWEVER...THIS EASTERN SHIFT WILL LEAD TO THE DEVELOPMENT OF CYCLONICALLY CURVED BUT GENERAL ZONAL FLOW PATTERN ACROSS THE NORTHEAST...WHICH SUGGESTS A MORE UNSETTLED PATTERN FOR THE LATE WORK WEEK. INDEED THIS LOOKS TO BE THE CASE AS A SERIES OF SHORTWAVES MOVE THROUGH THE CYCLONIC FLOW ALOFT...ONE INITIALLY WED NIGHT INTO THU...THEN A SECOND ON FRI. GFS HAS JOINED ECMWF WITH THIS SECONDARY WAVE...ALTHOUGH IS A BIT MORE PROGRESSIVE...WHICH LOOKS LIKE A BETTER SOLUTION GIVEN THE FAST FLOW ALOFT AND GENERALLY WEAKENING TREND AS THE WAVE INTERACTS WITH RIDGING TO THE E. DRY W FLOW FOR THE WEEKEND FAVORS A TRANSITION TO MOSTLY DRY WX...SO WILL CONTINUE WITH THIS TREND. SENSIBLE WX DETAILS... TUE INTO WED... CONDITIONS LOOK TO REMAIN MOSTLY DRY THROUGH THIS PERIOD AS HIGH PRES AND UPPER LVL RIDGING REMAINS IN CONTROL AS IT SHIFTS FURTHER E. APPROACHING WAVE OF LOW PRES AND ATTENDANT COLD FRONT WILL APPROACH ON WED BUT SOUNDINGS SUGGEST MOISTURE LOADING IS SLOW ENOUGH THAT IT SHOULD DELAY ANY PRECIP ONSET UNTIL WED EVENING/NIGHT. EXPECT GRADUAL WARMING AND INCREASING DWPTS UNDER S-SW RETURN FLOW. HIGHS WILL BE IN THE MID 60S TO NEAR 70 EACH DAY /SLIGHTLY ABOVE NORMAL/ WITH LOWS IN THE MID 60S TO LOW 50S. WED NIGHT INTO FRI... INITIAL SHORTWAVE ENERGY WILL DRY A LOW PRES NW OF THE REGION ALLOWING ITS ATTENDANT COLD FRONT TO SLIDE THROUGH THE REGION WED NIGHT INTO THU. BEST PV ANOMALY...STRONGEST LLJ...AND TIGHTEST BAROCLINICITY ALL SLIDE N AND W OF SRN NEW ENGLAND...SO SUSPECT THAT BULK OF THE RAINFALL WILL SHIFT NW WITH THE PARENT LOW. HOWEVER...DO NOTE THAT PWAT VALUES AVERAGE 1.0-1.25 INCHES SO SCT- WIDESPREAD -SHRA WILL LIKELY AFFECT THE REGION INTO THE EARLY HALF OF THE DAY THU DESPITE THE BETTER DYNAMICS SHIFTING N. A BRIEF DRY PERIOD THEN FOLLOWS INTO LATE THU NIGHT AS THE COLD FRONT STALLS OFFSHORE AND A SECOND FRONTAL WAVE MOVES UP FROM THE SE STATES. AS MENTIONED ABOVE...WILL LEAN TOWARD THE MORE PROGRESSIVE GFS...SUGGESTING PRECIP GENERALLY ENDS BY AFTERNOON FRI. ONCE AGAIN...JUST -SHRA...SO NOT EXPECTING A WASHOUT WITH THIS FEATURE EITHER. TEMPERATURES WILL LEAN CLOSE TO NORMAL WITH HIGHS AROUND THE MID 60S AND TEMPS IN THE UPPER 40S TO LOW 50S THROUGH THE PERIOD. THIS WEEKEND... MAINLY DRY WX PREVAILS AS NOSE OF HIGH PRES APPROACHES FROM THE SW AND W FLOW DEVELOPS. GIVEN CYCLONIC FLOW ALOFT...CAN/T RULE OUT SOME CLOUDS AND POSSIBLY EVEN AN ISOLATED -SHRA...BUT THAT LATTER WOULD LIKELY BE FEW AND FAR BETWEEN. THEREFORE...WILL CONTINUE WITH PREVIOUS SHIFT THINKING OF A DRY FORECAST FOR THE WEEKEND. COOL AIRMASS SETTLES IN WITH CAA ALOFT...SO EXPECT TEMPS NEAR TO SLIGHTLY COOLER THAN NORMAL. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE. 00Z UPDATE...MINOR CHANGES TO THE TAFS... BAND OF LOW CLOUDS WITH MIXED MVFR LOW-VFR CIGS WILL CONTINUE TO GRADUALLY SHIFT W AND DIMINISH THROUGH THE OVERNIGHT HOURS...BUT MAY LINGER A BIT LONGER. THIS WILL CONTINUE TO AFFECT TAF SITES IN VOF CT VALLEY THROUGH ABOUT 04Z. PATCHY FOG WITH LOCAL MVFR/IFR LATE TONIGHT AND EARLY MON MORNING. PARTICULARLY AT PRONE TAF SITES. LIGHT WINDS MON WILL RESULT IN AFTERNOON SEA BREEZES. VFR CIGS RETURN MON NIGHT WITH POTENTIAL FOR MVFR CIGS ACROSS INTERIOR TOWARD DAYBREAK TUE. LOCAL IFR IN FOG ACROSS VALLEYS. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. ALTHOUGH EXACT TIMING OF SCT CLOUDS THIS EVENING IS SOMEWHAT UNCERTAIN. OUTLOOK...TUESDAY THROUGH FRIDAY... TUE THROUGH WED...HIGH CONFIDENCE. MAINLY VFR. A FEW SPOTS OF MVFR FOG AT TYPICALLY PRONE AIRPORTS TUE NIGHT. SOME -SHRA IN THE W AND SW BY LATE WED EVENING. THU AND FRI...MODERATE CONFIDENCE. PERIODS OF MVFR IN SCT -SHRA AND FOG. OTHERWISE...SOME VFR POSSIBLE AS WELL. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH MONDAY NIGHT/...HIGH CONFIDENCE. WILL BE CLEARING THE ALL SMALL CRAFT ADVISORIES SAVE FOR THE SOUTHERN AND SOUTHEASTERN OCEAN WATERS WITH THE 00Z UPDATE... E/NE WINDS WERE DIMINISHING AND WILL CONTINUE TO DO SO TONIGHT AS HIGH PRESSURE BECOMES CENTERED OVER SOUTHERN NEW ENGLAND. SEAS WILL TAKE LONGER TO SUBSIDE...AS SEAS FALL BELOW 5 FT ON NEARSHORE WATERS THIS EVENING AND FARTHER OFFSHORE LATE TONIGHT. SCA REMAINS POSTED TO REFLECT THESE TIMES. WEAK GRADIENT MON WITH FLAT SEAS AND AFTERNOON SEA BREEZES. LIGHT S/SW FLOW GETS UNDERWAY MON NIGHT AS HIGH PRESSURE MOVES OFFSHORE. OUTLOOK...TUESDAY THROUGH FRIDAY... TUE...HIGH CONFIDENCE. FINE BOATING WEATHER WITH LIGHT WINDS AS HIGH PRES REMAINS OVER THE AREA. WED INTO FRI...MODERATE CONFIDENCE. WINDS SHIFT TO THE S WED AND THEN BACK TO THE W BY THU. HOWEVER...MOST WIND GUSTS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH THE PERIOD. AS SUCH...SEAS ALSO REMAIN GENERALLY BELOW 5 FT...EVEN IN BUILDING S SWELL. OTHERWISE...SOME SHOWERS AND FOG MAY LEAD TO VSBY REDUCTIONS AT TIME WITH BEST CHANCE FOR IMPROVEMENT DURING THE DAY THU AND THEN AGAIN DURING THE DAY FRI. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...FROST ADVISORY FROM 3 AM TO 9 AM EDT MONDAY FOR MAZ003-004-026. NH...FROST ADVISORY FROM 3 AM TO 9 AM EDT MONDAY FOR NHZ011-015. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ235- 237-250. SMALL CRAFT ADVISORY UNTIL 4 AM EDT MONDAY FOR ANZ254>256. && $$ SYNOPSIS...DOODY/JWD NEAR TERM...DOODY/JWD SHORT TERM...JWD LONG TERM...DOODY AVIATION...DOODY/JWD MARINE...DOODY/JWD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1011 PM CDT SUN OCT 13 2013 .DISCUSSION... 734 PM CDT TEMPERATURES ARE ALREADY DROPPING MUCH FASTER THAN FORECAST SO LOWERED MIN TEMPS FOR TONIGHT AND ADJUSTED TEMP TRENDS. IN ADDITION EXPANDED THE FROST ADVISORY TO INCLUDE THE FAR SOUTHERN COUNTIES IN IL AND LAKE COUNTY IL. PARTS OF INDIANA MAY SEE AREAS OF FROST TONIGHT...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE ANY INDIANA COUNTIES IN THE FROST ADVISORY. LASTLY...LOWERED SKY COVER ACROSS THE LAKE... NW INDIANA...AND NE ILLINOIS TOMORROW AS THINKING LIGHT WINDS AND THE VERY DRY AIR OVERHEAD WILL LIMIT THE CLOUD COVER. OTHERWISE THE CURRENT FORECAST IS ON TRACK. JEE //PREV DISCUSSION... 305 PM CDT THE CHALLENGES WITH THE FORECAST ARE FROST POTENTIAL TONIGHT...FOLLOWED BY MORNING CLOUDS OFF THE LAKE ON MONDAY AND THEN RAIN CHANCES TUESDAY. FINALLY THE SUBSEQUENT NOTEWORTHY COOL DOWN INTO NEXT WEEK WILL BECOME A GREATER FORECAST CHALLENGE AS THIS WEEK PROGRESSES. SYNOPSIS...EXPANSIVE 1030MB CANADIAN HIGH PRESSURE IS IN PLACE ACROSS THE UPPER MIDWEST AND WILL SHIFT DIRECTLY OVER THE AREA BY EVENING. COOL BUT MORE SEASONAL 850MB TEMPS WERE OBSERVED ACROSS THE AREA THIS MORNING...INCLUDING +3C AT DVN. ALMOST ALL 12Z GUIDANCE INITIALIZED TOO MILD WITH THIS LOW-LEVEL COOL AIR. THAT MAY BE ONE REASON WHY MOST OF THE GUIDANCE SOLUTIONS FOR TEMPS TONIGHT ARE LIKELY TOO WARM. TONIGHT...SATELLITE REVEALS THE ONLY CLOUDS IN THE IMMEDIATE REGION ARE ACROSS NORTHERN LAKE MI...AND THESE ARE IN PLACE THANKS TO THE COLD AIR MASS MOVING OVER THE STILL MILD WATERS. AS THE HIGH DOES MOVE OVER THE AREA...850-1000MB LOW WILL TURN MORE NORTHERLY AND THEN NORTHEASTERLY. SPEEDS WILL DROP BUT ARE LIKELY ENOUGH TO ADVECT LAKE-INDUCED STEEP LAPSE RATES AND SATURATION ON TOP OF THIS INDICATIVE OF STRATOCU INTO FAR NW IN AND THEN FAR NE IL AFTER MIDNIGHT. NAM AND LOCAL ARW SOUNDINGS AND LOW-LEVEL RH FIELDS ARE IN AGREEMENT TO THIS SOLUTIONS...ALONG WITH SPC WRF COLUMN CONDENSATE WHICH SEEMS TO DO WELL WITH STRATOCU IN THESE SITUATIONS. THIS WILL LIKELY SLOW OR EVEN HALT THE TEMPERATURE DROP LATE TONIGHT IN DOWNTOWN CHICAGO AND OTHER LAKE ADJACENT AREAS. FOR THE REMAINDER OF THE CWA...A PICTURE PERFECT RADIATIONAL COOLING EVENING AND OVERNIGHT IS SHAPING UP AS THE ATMOSPHERE SHOULD DECOUPLE BY EARLY TO MID EVE. HAD ADJUSTED THE HOURLY TEMPERATURE TREND TO REFLECT QUICK COOLING AFTER DARK...AND FOR MINS HAVE CONSIDERED LAST NIGHTS TEMPS STRONGLY AS A BASELINE AS OPPOSED TO ANY GUIDANCE SOURCE. THERE IS LITTLE REASON FOR OUTLYING AREAS TO BE WARMER THAN THEY WERE THIS MORNING...AND CURRENT SURFACE DEW POINTS LEAN THAT ROUTE AS WELL INDICATING THE BOUNDARY LAYER IS WELL MIXED TODAY. SO EXPECTING WIDESPREAD 32 TO 35 ACROSS NORTH CENTRAL IL WITH MID TO UPPER 30S ELSEWHERE IN OUTLYING AREAS. CONSIDERING COCORAHS OBSERVER COMMENTS THIS MORNING REPORTING PATCHY FROST...WOULD EXPECT CLOSER TO A WIDESPREAD FROST IN NORTH CENTRAL IL. CONSIDERING THE MILD NIGHT AS OF RECENT...WE HAVE GONE AHEAD AND COLLABORATED A FROST ADVISORY FOR LATE TONIGHT...THE FIRST SUCH ADVISORY OF THE SEASON. MONDAY...THE HIGH WILL REMAIN IN CONTROL ON COLUMBUS DAY. THE LAKE EFFECT CLOUDS ARE ANTICIPATED TO LINGER IN NORTHEAST IL...POSSIBLY AS FAR WEST AS NORTH CENTRAL IL...BUT AMOUNT OF COVERAGE IS LOW CONFIDENCE. THE CLOUD DEPTH LOOKS TO BE AT OR UNDER 3K FT AT MOST OVER THE LAKE SO ANY STRATOCU MAY BEGIN TO THIN QUICKLY BY LATE MORNING. MIXING LOOKS TO BE TO 875MB...AND THAT SHOULD SUPPORT 60S ACROSS THE AREA. TUESDAY AND WEDNESDAY...A PRONOUNCED UPPER TROUGH ACROSS UT/NV WILL SHIFT ENE INTO THE UPPER MIDWEST DURING THIS PERIOD...AND THIS WILL BE THE FIRST OF MULTIPLE UPPER WAVES EVOLVING EASTWARD ACROSS NORTH AMERICA DURING THE MIDDLE OF THIS WEEK. TOGETHER THESE WILL CARVE OUT A LONG WAVE TROUGH OVER THE CENTRAL PART OF THE CONTINENT...EXTENDING INTO THE MIDWEST BY WEEKS END. THIS FIRST WAVE ON TUESDAY LOOKS TO BRING THE BEST CHANCE OF RAIN TO THE AREA AS PRONOUNCED HEIGHT FALLS MOVE ACROSS THE AREA ALONG WITH DYNAMIC SUPPORT FOR ENHANCED LIFT AHEAD OF THE SYSTEM COOL FRONT. THE GFS REMAINS THE QUICKEST SOLUTION WITH THIS...BUT NOT BY MUCH AT ALL. THE MEAN OF THE SOLUTIONS PAINTS THE MORNING AND EARLY AFTERNOON WILL BE THE BEST CHANCE FOR WIDESPREAD SHOWERS AS THE MOISTURE TRANSPORT MAX POINTS INTO THE REGION. AS THE COLD FRONT SHIFTS EASTWARD THROUGH THE AREA LIKELY DURING TUESDAY AFTERNOON...THIS MAY PRESENT A BETTER CHANCE FOR THUNDER. INSTABILITY RETURN LOOKS TO BE VERY MODEST AT BEST...ESPECIALLY IF THERE IS MORNING WIDESPREAD CLOUDS AND RAIN. THE DRY SLOT STILL LOOKS TO EVOLVE OVER TUE NIGHT WITH ANY PRECIP LIKELY TO BE LIGHT AT THAT POINT. COLD AIR ADVECTION WRAPS AROUND THIS SYSTEM AND PREVAILS ON WED WITH HIGHS 10 TO 15 DEGREES COOLER THAN TUE. SMALL CHANCES FOR SHOWERS ARE IN WEDNESDAY AS THE COLD CORE SYSTEM MOVES OVERHEAD. THURSDAY AND BEYOND...THE SUCCESSIVE SHORT WAVE TROUGHS WILL LEAD TO PROGRESSIVE THICKNESS FALLS AND COOLING TEMPS. THE 850 0C ISOTHERM DROPS SOUTH INTO THE AREA ON FRIDAY IN THE GFS/EC MEAN SOLUTION WITH AN ASSOCIATED COLD FRONT. THIS SETS THE STAGE FOR THE FIRST POSSIBLE WIDESPREAD FREEZE ON FRIDAY OR SATURDAY NIGHT IF INDEED HIGH PRESSURE FOLLOWS WHICH IT LOOKS TO. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * POTENTIAL FOR A PERIOD OF HIGH-END MVFR CIGS VERY LATE TONIGHT/EARLY MONDAY MORNING. * LIGHT NORTH/VARIABLE WIND OVERNIGHT BECOMING EAST MONDAY. RATZER //DISCUSSION...UPDATED 00Z... DRY HIGH PRESSURE RIDGE WAS CENTERED OVER THE UPPER MISSISSIPPI VALLEY THIS EVENING...AND WILL CONTINUE TO BUILD EAST ACROSS THE WESTERN GREAT LAKES REGION OVERNIGHT AND MONDAY. LATE DAY LAKE BREEZE HAS PUSHED THROUGH ORD/MDW AS OF EARLY THIS EVENING... THOUGH EAST/NORTHEAST WINDS BEHIND LAKE BREEZE ARE EXPECTED TO EAST AND BECOME MORE NORTH/VARIABLE BY LATE EVENING WITH GOOD RADIATIONAL COOLING CONDITIONS IN DRY AIR MASS WITH WEAKENING GRADIENT NEAR THE SURFACE HIGH. OVERNIGHT WINDS LIKELY TO BECOME LIGHT/VARIABLE OR CALM AWAY FROM THE CITY OF CHICAGO. CLOSER TO THE CITY/LAKE...WILL LIKELY SEE A LAND BREEZE DEVELOP WITH NNW WINDS OR JUST VARIABLE DIRECTION DEVELOPING. WINDS ARE THEN EXPECTED TO TURN EASTERLY AROUND 10 KT AFTER LOW LEVEL MIX OUT MONDAY MORNING...AS SURFACE RIDGE DRIFTS SLOWLY EAST AND LOW PRESSURE BEGINS TO DEVELOP OVER THE WESTERN PLAINS. VERY DRY AIR MASS IN PLACE ACROSS THE TERMINALS EARLY THIS EVENING PROVIDING CLEAR SKIES AND EXCELLENT VISIBILITY. HOWEVER...AS DEEPER LOW LEVEL WINDS VEER TO THE NORTHEAST/EAST OFF THE LAKE TOWARD MORNING THERE IS THE POTENTIAL FOR A PERIOD OF LAKE-INDUCED STRATOCU TO PUSH WESTWARD INTO NORTHEAST IL. LATE AFTERNOON/EARLY EVENING SATELLITE IMAGERY SUGGESTS SOME OF THE GUIDANCE DEPICTIONS OF THE EXTENT OF CLOUD COVER ON THE SOUTH END OF THE LAKE MAY BE A BIT OVERDONE...SO CONFIDENCE IN DEVELOPING A SOLID CEILING INTO ORD/MDW IS QUITE LOW AT THIS TIME. IF IT WERE TO DEVELOP...IT WOULD LIKELY BE IN THE 12-15Z TIME FRAME AND ABOVE 2500 FT AGL. OTHERWISE...VFR CONDITIONS EXPECTED. RATZER //ORD AND MDW CONFIDENCE...UPDATED 03Z... * HIGH CONFIDENCE IN WIND TRENDS. * LOW CONFIDENCE IN MVFR CIG DEVELOPMENT EARLY MONDAY MORNING. RATZER //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY...SHRA/FEW TSRA LIKELY. MVFR POSSIBLE. WEDNESDAY...CHANCE SHRA. MVFR POSSIBLE. THURSDAY...VFR. FRIDAY AND SATURDAY...SLIGHT CHANCE SHRA. MAINLY VFR. RATZER && .MARINE... 225 PM CDT WINDS WILL VEER TO OUT OF THE NORTH AND NORTHEAST AND DIMINISH TONIGHT AS HIGH PRESSURE CENTERED OVER NORTHWEST IOWA AT MID AFTERNOON BUILDS ACROSS THE UPPER MIDWEST AND UPPER GREAT LAKES DURING THE NIGHT. AS THE HIGH CONTINUES ON ACROSS ONTARIO TO SOUTHERN QUEBEC MONDAY AND MONDAY NIGHT LOW PRESSURE WILL BE ORGANIZING OVER THE CENTRAL HIGH PLAINS AND DEEPENING AS IT MOVES NORTHEASTWARD TO SOUTHERN MINNESOTA. WITH THE WESTERN GREAT LAKES BETWEEN THE DEPARTING HIGH AND THE APPROACHING STRENGTHENING LOW WINDS ON LAKE MICHIGAN INCREASE TO MODERATE AND FRESH BREEZES WHILE VEERING TO OUT OF THE SOUTHEAST AND SOUTH DURING MONDAY NIGHT AND TUESDAY. THE LOW MOVES ACROSS NORTHERN WISCONSIN AND THE EASTERN UPPER PENINSULA OF MICHIGAN TUESDAY NIGHT AND WEDNESDAY. AS IT DOES IT WILL PUSH A COLD FRONT EASTWARD ACROSS LAKE MICHIGAN. TRS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ023-ILZ032-ILZ033- ILZ039...3 AM MONDAY TO 8 AM MONDAY. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion National Weather Service Lincoln IL 826 PM CDT Sun Oct 13 2013 .DISCUSSION... ISSUED 815 PM CDT Sun Oct 13 2013 In the process of updating the ZFP this evening to include a Frost Advisory for areas mainly north of a Lewistown to Bloomington line. Early morning temperatures are expected to drop into the middle 30s across the north for a time Monday morning allowing frost to form, especially away from the metropolitan areas of Peoria and Bloomington. Further south, have added some patchy frost for early Monday morning. Early evening temperatures were dropping off rapidly with readings already in the middle 40s across the far north (Galesburg and Lacon). The latest HRRR model suggests the threat for a more prolonged period of calm winds north of I-74 in the 09z-12z time frame as the center of the high will shift just north of our area. Early evening dew points have settled into the lower to middle 30s and that usually gives us a good idea where the early morning low may dip to with this type of radiational cooling setup, especially in low lying areas and in locations away from the city. Have edged the overnight lows down a degree or two further south and as mentioned above, added some patchy frost as well, but the best threat for our first frost of the season will be mainly north of I-74 early Monday morning. The updated zones should be out by 0145z. Smith && .AVIATION... ISSUED 610 PM CDT Sun Oct 13 2013 VFR conditions are expected through this forecast period (00z Tue). High pressure will track to our north tonight and finally pull away from the area during the day on Monday. A clear sky is expected tonight into a good part of Monday before high level clouds start to move in ahead of our next weather system slated to bring in some rain late Monday night or Tuesday morning. Surface winds tonight will be from the northeast to east at 3 to 8 kts, and then winds will gradually veer more into the east and southeast at around 10 kts by Monday afternoon. Smith && .PREV DISCUSSION... ISSUED 249 PM CDT Sun Oct 13 2013 After collaboration with DVN and LOT, have added patchy frost to areas across the northwest forecast area and made some minor adjustments to other grids for late tonight and early Monday morning. Do not expect frost to be widespread enough to warrant an advisory, but wind protected areas may see some patchy frost. && .ILX WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY from 3 AM to 8 AM CDT Monday FOR ILZ027>031- 036>038. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
519 PM CDT SAT OCT 12 2013 .DISCUSSION... 253 PM CDT SYNOPSIS...A COLD FRONT CONTINUES TO SWING THROUGH THIS AFTERNOON WITH SCATTERED SHOWERS AND ISOLATED THUNDER ALONG IT. DRY WEATHER AND SEASONAL TEMPS ARE EXPECTED EARLY NEXT WEEK WITH ANOTHER LOW BRINGING SHOWERS AND SOME STORMS TUESDAY AND LINGERING SHOWERS ON WEDNESDAY. BELOW NORMAL TEMPS AND DRY WEATHER ARE THEN EXPECTED LATE NEXT WEEK. REST OF TODAY AND TONIGHT... THE COLD FRONT CURRENTLY STRETCHES FROM GREEN BAY TO AURORA TO CHAMPAIGN AND IT WILL CONTINUE EAST INTO THIS EVENING. STILL ONLY EXPECTING SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS ALONG THE FRONT...AND WINDS WILL TURN WEST AND GUST TO AROUND 20 KT BEHIND IT. INSTABILITY IS WEAK ALONG THE FRONT WITH THE LATEST RAP ANALYSIS SUGGESTING MAX CAPE VALUES OF 500 J/KG. THE BETTER SHOWER AND STORM COVERAGE WILL BE NORTH OF OUR CWA ASSOCIATED WITH A SHORTWAVE MOVING INTO WI. THAT BEING SAID A BRIEF MODERATE TO HEAVY SHOWER IS POSSIBLE AS PWAT VALUES ARE AROUND 1.2 INCHES THIS AFTN. HEAVIER SHOWERS COULD LOWER VISIBILITIES TO 1 TO 3 MILES. TEMPS WILL FALL UNDER THE SHOWERS...BUT PLACES OUT WEST ARE EXPECTED TO WARM A BIT AS THE SUN BREAKS OUT AGAIN. LOWERED LOW TEMPS FOR TONIGHT GIVEN THAT WINDS WILL BE DIMINISHING AND CLEAR SKIES. WENT A COUPLE OF DEGREES ABOVE THE MIN DEWPOINT...BUT WONDERING IF SOME ISOLATED AREAS WILL DROP A BIT LOWER THAN FORECAST. SUNDAY AND MONDAY... THE UPPER LEVEL PATTERN BECOMES ZONAL BEHIND THE UPPER LEVEL TROUGH TOMORROW WITH WEAK RIDGING ALOFT SUNDAY NIGHT INTO MONDAY. A SURFACE HIGH MOVES OVER THE REGION TOMORROW AND CONTINUES EAST REACHING SOUTHERN QUEBEC BY TUESDAY MORNING. SUNDAY LOOKS PLEASANT WITH SEASONAL TEMPS IN THE 60S...COOLER BY THE LAKE DUE TO ONSHORE FLOW. WINDS TURN SOUTHEAST MONDAY WITH TEMPS A BIT WARMER IN THE MID 60S TO AROUND 70 SOUTH. TUESDAY AND WEDNESDAY... AN UPPER LEVEL TROUGH CURRENTLY OVER NEVADA WILL MOVE OVER THE NORTHERN PLAINS MONDAY NIGHT AS A CLOSED LOW. IT WILL REMAIN RELATIVELY STATIONARY TUESDAY BEFORE MOVING OVER THE NORTHERN MISSISSIPPI RIVER VALLEY TUESDAY OR TUESDAY NIGHT. THE BLOCKING LOW CURRENTLY OFF THE THE CENTRAL ATLANTIC COAST SLOWLY WEAKENS AND SHIFTS SOUTH EARLY NEXT WEEK...WHICH WILL ONCE AGAIN RESULT IN A SLOWLY MOVING LOW THAT PASSES TO OUR NORTHWEST. IN GENERAL THE GFS AND NAM ARE MUCH FASTER THAN OTHER GUIDANCE WITH THE LOW...AND WILL BASE THE FORECAST OFF OF THE SLOWER ECMWF PER THE WPC GUIDANCE EVALUATION. THE ASSOCIATED SURFACE LOW WILL ALSO BEGIN OVER THE NORTHERN PLAINS BUT A BIT MORE TO THE EAST...AND THE LOW REMAINS NEGATIVELY STACKED WITH HEIGHT THROUGH THE END OF THE WEEK. THE LOW ALSO HAS JET SUPPORT AS THE UPPER LEVEL JET STRENGTHENS WEDNESDAY WHILE THE LOW IS IN THE FAVORABLE LEFT EXIT REGION. THE SURFACE LOW BEGINS TO CROSS THE MISSISSIPPI RIVER VALLEY TUESDAY WITH ITS WARM FRONT LIFTING THROUGH THE CWA TUESDAY AFTERNOON. EXPECTING SHOWERS AND A FEW STORMS AHEAD OF AND ALONG THE FRONT TUESDAY WITH A BETTER CHANCE OF STORMS TUESDAY AFTERNOON. INSTABILITY IS WEAK TUESDAY SO KEPT JUST A CHANCE OF TS GOING...WITH AFTN CAPE VALUES FORECAST TO BE 500 J/KG OR LESS. MOISTURE HOWEVER WILL NOT BE AN ISSUE...WITH PWATS OF 1-1.5 INCHES. THE LOWS COLD FRONT SWINGS THROUGH TUESDAY EVENING/NIGHT WITH ADDITIONAL SHOWERS EXPECTED INTO WEDNESDAY. GUIDANCE STILL SUGGESTS THE DRY SLOT WILL LEAD TO A FEW DRY HOURS WEDNESDAY AFTERNOON BEFORE SOME LIGHT WRAP AROUND PRECIP MOVES IN WEDNESDAY NIGHT. THE LOW WILL BE MOVING OFF TO THE NE AT THIS TIME SO WILL KEEP SLIGHT CHANCE OF PRECIP MAINLY ALONG THE IL/WI STATE LINE. FOR TEMPS...EXPECTING A BRIEF WARM UP TUESDAY INTO THE UPPER 60S AND 70S AS WE ARE IN THE WARM SECTOR OF THE LOW. THEN BACK TO REALITY WEDNESDAY WITH MORE SEASONAL TEMPS IN THE UPPER 50S TO LOW 60S. EXTENDED...THURSDAY AND FRIDAY... GUIDANCE INDICATES A SHORTWAVE WILL MOVE OVER THE CWA THURSDAY...HOWEVER GUIDANCE DIFFERS ON HOW MUCH MOISTURE WILL BE ASSOCIATED WITH THE DISTURBANCE. GIVEN THE DIFFERENCES AND WHERE THE SHORTWAVE MOVES THROUGH THE CWA...WENT WITH A DRY FORECAST FOR THURSDAY. FRIDAY ALSO LOOKS DRY WITH A COOLING TREND AS AN UPPER LEVEL TROUGH APPROACHES FROM THE EAST. HOWEVER...THE JET REMAINS OVERHEAD KEEPING THE MUCH COOLER AIR TO OUR NORTH. IN GENERAL HAVE BELOW NORMAL TEMPS IN FOR LATE THIS WEEK...AND NEXT WEEKEND IS STILL LOOKING COLD AS PREVIOUSLY ADVERTISED. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * VFR CEILINGS SCATTERING OUT THIS NEXT HOUR. * SOUTHWEST WINDS TURNING TO THE WEST THIS NEXT HOUR...WITH MID TEEN GUSTS THROUGH EARLY EVENING. RODRIGUEZ //DISCUSSION...UPDATED 18Z... THE COLD FRONT PROGRESSION HAS CONTINUED TO BE QUICKER THAN INITIALLY THOUGHT...WHICH MEANS A SLIGHTLY EARLIER DEPARTURE OF MVFR CLOUDS ALONG WITH THE WIND SHIFT TO WESTERLY. HAVE ADJUSTED ACCORDINGLY QUICKER IN TAFS. //PREV DISCUSSION...UPDATED 18Z... A COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD ACROSS NORTHERN IL AND NORTHWEST IN THROUGH THE AFTERNOON. AHEAD OF THIS...SCATTERED SHOWERS WILL CONTINUE. A MORE DEFINED AXIS OF SHOWERS AND EMBEDDED STORMS FROM SE WI THROUGH MORRIS WILL LIKELY HOLD TOGETHER AS IT MOVES NORTHEAST AND IS THE REASON FOR THE TEMPO OF TSRA AT ORD. WHILE IT IS TWO HOURS...THE WINDOW OF TIME FOR THUNDER IS LIKELY 45 MIN OR LESS /IT JUST HAPPENS TO SPLIT THE 19Z HOUR/. WINDS SHOULD MAINTAIN SSW THROUGH THE STORMS...AND IF THE STORMS DO SHIFT THE WINDS IT WOULD ONLY BE SLIGHTLY TO SW. MOISTURE ALONG THE FRONT WILL KEEP MVFR CIGS IN PLACE BEHIND THE SHRA/TSRA FOR A 2-3 HOUR WINDOW WITH A FEW SITES IN WESTERN IL INDICATING CIGS AT OR BELOW 1500 FT...BUT THAT LOW OF CIG WILL NOT LAST LONG IF IT OCCURS. AFTER FRONTAL PASSAGE LATE THIS AFTERNOON WINDS WILL TURN W TO WNW AND THE SKY WILL CLEAR. THE GRADIENT WILL EASE ENOUGH ON SUNDAY TO LIKELY ALLOW WINDS TO TURN NE OFF OF LAKE MICHIGAN AT ORD AND MDW...AND AT THIS POINT THAT SEEMS MOST FAVORED IN THE EARLY AFTERNOON. //ORD AND MDW CONFIDENCE...UPDATED 22Z... * HIGH CONFIDENCE WITH CEILING TRENDS. * HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT AND MONDAY...VFR. TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE. WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR. FRIDAY...VFR. MTF && .MARINE... 300 PM CDT A COLD FRONT TRAILING FROM LOW PRESSURE INCHES IN EASTERN MANITOBA WILL MOVE EAST ACROSS LAKE MICHIGAN LATE THIS AFTERNOON AND EARLY THIS EVENING SHIFTING WINDS TO OUT OF THE WEST AND NORTHWEST. THE LOW CONTINUES NORTH-NORTHEASTWARD TO SOUTHWESTERN HUDSON BAY TONIGHT AND HIGH PRESSURE MOVES NORTHEAST FROM THE CENTRAL HIGH PLAINS TO IOWA. NORTHWEST AND NORTH WINDS WILL DIMINISH SUNDAY AS THE HIGH CONTINUE TO THE NORTHEAST....REACHING THE UPPER GREAT LAKES BY MONDAY MORNING. LOW PRESSURE TRACKS NORTHEASTWARD FROM THE CENTRAL HIGH PLAINS TO IOWA MONDAY AND MONDAY NIGHT. IN RESPONSE WINDS ON LAKE MICHIGAN WILL VEER TO OUT OF THE EAST AND SOUTHEAST AND GRADUALLY INCREASE. THIS LOW WILL MOVE ACROSS WISCONSIN AND CENTRAL LAKE MICHIGAN DURING TUESDAY AND TUESDAY NIGHT...AND THEN ON ACROSS ONTARIO TO WESTERN QUEBEC WEDNESDAY AND THURSDAY. TRS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
301 PM CDT SAT OCT 12 2013 .DISCUSSION... 253 PM CDT SYNOPSIS...A COLD FRONT CONTINUES TO SWING THROUGH THIS AFTERNOON WITH SCATTERED SHOWERS AND ISOLATED THUNDER ALONG IT. DRY WEATHER AND SEASONAL TEMPS ARE EXPECTED EARLY NEXT WEEK WITH ANOTHER LOW BRINGING SHOWERS AND SOME STORMS TUESDAY AND LINGERING SHOWERS ON WEDNESDAY. BELOW NORMAL TEMPS AND DRY WEATHER ARE THEN EXPECTED LATE NEXT WEEK. REST OF TODAY AND TONIGHT... THE COLD FRONT CURRENTLY STRETCHES FROM GREEN BAY TO AURORA TO CHAMPAIGN AND IT WILL CONTINUE EAST INTO THIS EVENING. STILL ONLY EXPECTING SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS ALONG THE FRONT...AND WINDS WILL TURN WEST AND GUST TO AROUND 20 KT BEHIND IT. INSTABILITY IS WEAK ALONG THE FRONT WITH THE LATEST RAP ANALYSIS SUGGESTING MAX CAPE VALUES OF 500 J/KG. THE BETTER SHOWER AND STORM COVERAGE WILL BE NORTH OF OUR CWA ASSOCIATED WITH A SHORTWAVE MOVING INTO WI. THAT BEING SAID A BRIEF MODERATE TO HEAVY SHOWER IS POSSIBLE AS PWAT VALUES ARE AROUND 1.2 INCHES THIS AFTN. HEAVIER SHOWERS COULD LOWER VISIBILITIES TO 1 TO 3 MILES. TEMPS WILL FALL UNDER THE SHOWERS...BUT PLACES OUT WEST ARE EXPECTED TO WARM A BIT AS THE SUN BREAKS OUT AGAIN. LOWERED LOW TEMPS FOR TONIGHT GIVEN THAT WINDS WILL BE DIMINISHING AND CLEAR SKIES. WENT A COUPLE OF DEGREES ABOVE THE MIN DEWPOINT...BUT WONDERING IF SOME ISOLATED AREAS WILL DROP A BIT LOWER THAN FORECAST. SUNDAY AND MONDAY... THE UPPER LEVEL PATTERN BECOMES ZONAL BEHIND THE UPPER LEVEL TROUGH TOMORROW WITH WEAK RIDGING ALOFT SUNDAY NIGHT INTO MONDAY. A SURFACE HIGH MOVES OVER THE REGION TOMORROW AND CONTINUES EAST REACHING SOUTHERN QUEBEC BY TUESDAY MORNING. SUNDAY LOOKS PLEASANT WITH SEASONAL TEMPS IN THE 60S...COOLER BY THE LAKE DUE TO ONSHORE FLOW. WINDS TURN SOUTHEAST MONDAY WITH TEMPS A BIT WARMER IN THE MID 60S TO AROUND 70 SOUTH. TUESDAY AND WEDNESDAY... AN UPPER LEVEL TROUGH CURRENTLY OVER NEVADA WILL MOVE OVER THE NORTHERN PLAINS MONDAY NIGHT AS A CLOSED LOW. IT WILL REMAIN RELATIVELY STATIONARY TUESDAY BEFORE MOVING OVER THE NORTHERN MISSISSIPPI RIVER VALLEY TUESDAY OR TUESDAY NIGHT. THE BLOCKING LOW CURRENTLY OFF THE THE CENTRAL ATLANTIC COAST SLOWLY WEAKENS AND SHIFTS SOUTH EARLY NEXT WEEK...WHICH WILL ONCE AGAIN RESULT IN A SLOWLY MOVING LOW THAT PASSES TO OUR NORTHWEST. IN GENERAL THE GFS AND NAM ARE MUCH FASTER THAN OTHER GUIDANCE WITH THE LOW...AND WILL BASE THE FORECAST OFF OF THE SLOWER ECMWF PER THE WPC GUIDANCE EVALUATION. THE ASSOCIATED SURFACE LOW WILL ALSO BEGIN OVER THE NORTHERN PLAINS BUT A BIT MORE TO THE EAST...AND THE LOW REMAINS NEGATIVELY STACKED WITH HEIGHT THROUGH THE END OF THE WEEK. THE LOW ALSO HAS JET SUPPORT AS THE UPPER LEVEL JET STRENGTHENS WEDNESDAY WHILE THE LOW IS IN THE FAVORABLE LEFT EXIT REGION. THE SURFACE LOW BEGINS TO CROSS THE MISSISSIPPI RIVER VALLEY TUESDAY WITH ITS WARM FRONT LIFTING THROUGH THE CWA TUESDAY AFTERNOON. EXPECTING SHOWERS AND A FEW STORMS AHEAD OF AND ALONG THE FRONT TUESDAY WITH A BETTER CHANCE OF STORMS TUESDAY AFTERNOON. INSTABILITY IS WEAK TUESDAY SO KEPT JUST A CHANCE OF TS GOING...WITH AFTN CAPE VALUES FORECAST TO BE 500 J/KG OR LESS. MOISTURE HOWEVER WILL NOT BE AN ISSUE...WITH PWATS OF 1-1.5 INCHES. THE LOWS COLD FRONT SWINGS THROUGH TUESDAY EVENING/NIGHT WITH ADDITIONAL SHOWERS EXPECTED INTO WEDNESDAY. GUIDANCE STILL SUGGESTS THE DRY SLOT WILL LEAD TO A FEW DRY HOURS WEDNESDAY AFTERNOON BEFORE SOME LIGHT WRAP AROUND PRECIP MOVES IN WEDNESDAY NIGHT. THE LOW WILL BE MOVING OFF TO THE NE AT THIS TIME SO WILL KEEP SLIGHT CHANCE OF PRECIP MAINLY ALONG THE IL/WI STATE LINE. FOR TEMPS...EXPECTING A BRIEF WARM UP TUESDAY INTO THE UPPER 60S AND 70S AS WE ARE IN THE WARM SECTOR OF THE LOW. THEN BACK TO REALITY WEDNESDAY WITH MORE SEASONAL TEMPS IN THE UPPER 50S TO LOW 60S. EXTENDED...THURSDAY AND FRIDAY... GUIDANCE INDICATES A SHORTWAVE WILL MOVE OVER THE CWA THURSDAY...HOWEVER GUIDANCE DIFFERS ON HOW MUCH MOISTURE WILL BE ASSOCIATED WITH THE DISTURBANCE. GIVEN THE DIFFERENCES AND WHERE THE SHORTWAVE MOVES THROUGH THE CWA...WENT WITH A DRY FORECAST FOR THURSDAY. FRIDAY ALSO LOOKS DRY WITH A COOLING TREND AS AN UPPER LEVEL TROUGH APPROACHES FROM THE EAST. HOWEVER...THE JET REMAINS OVERHEAD KEEPING THE MUCH COOLER AIR TO OUR NORTH. IN GENERAL HAVE BELOW NORMAL TEMPS IN FOR LATE THIS WEEK...AND NEXT WEEKEND IS STILL LOOKING COLD AS PREVIOUSLY ADVERTISED. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * A 30-45 MIN PERIOD OF TSRA AT/NEAR ORD AND POTENTIALLY MDW PRIOR TO 20Z. * MVFR CIGS THIS AFTERNOON...INCLUDING FOR A 2-3 HR PERIOD AFTER THE SHRA/TSRA. BRIEF CIGS AROUND 1500 FT POSSIBLE. * WIND SHIFT TO WSW AND EVENTUALLY W OR WNW BETWEEN 23Z AND 01Z. * WINDS TURNING NE DURING SUNDAY AFTERNOON. //DISCUSSION...UPDATED 18Z... A COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD ACROSS NORTHERN IL AND NORTHWEST IN THROUGH THE AFTERNOON. AHEAD OF THIS...SCATTERED SHOWERS WILL CONTINUE. A MORE DEFINED AXIS OF SHOWERS AND EMBEDDED STORMS FROM SE WI THROUGH MORRIS WILL LIKELY HOLD TOGETHER AS IT MOVES NORTHEAST AND IS THE REASON FOR THE TEMPO OF TSRA AT ORD. WHILE IT IS TWO HOURS...THE WINDOW OF TIME FOR THUNDER IS LIKELY 45 MIN OR LESS /IT JUST HAPPENS TO SPLIT THE 19Z HOUR/. WINDS SHOULD MAINTAIN SSW THROUGH THE STORMS...AND IF THE STORMS DO SHIFT THE WINDS IT WOULD ONLY BE SLIGHTLY TO SW. MOISTURE ALONG THE FRONT WILL KEEP MVFR CIGS IN PLACE BEHIND THE SHRA/TSRA FOR A 2-3 HOUR WINDOW WITH A FEW SITES IN WESTERN IL INDICATING CIGS AT OR BELOW 1500 FT...BUT THAT LOW OF CIG WILL NOT LAST LONG IF IT OCCURS. AFTER FRONTAL PASSAGE LATE THIS AFTERNOON WINDS WILL TURN W TO WNW AND THE SKY WILL CLEAR. THE GRADIENT WILL EASE ENOUGH ON SUNDAY TO LIKELY ALLOW WINDS TO TURN NE OFF OF LAKE MICHIGAN AT ORD AND MDW...AND AT THIS POINT THAT SEEMS MOST FAVORED IN THE EARLY AFTERNOON. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN SHRA TIMING AND MEDIUM CONFIDENCE IN TSRA OCCURRING AT ORD. HIGH CONFIDENCE IN TSRA AT LEAST NEARBY. * HIGH CONFIDENCE IN MVFR CIGS AT ORD AND MEDIUM CONFIDENCE AT MDW. HIGH CONFIDENCE THAT IF CIGS DROP TO 1500 FT IT WILL BE BRIEF /LIKELY UNDER ONE HOUR/. * HIGH CONFIDENCE IN WSW WINDS BY 23Z. * MEDIUM CONFIDENCE ON EARLY AFTERNOON TIMING OF WINDS TURNING NE ON SUNDAY. //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT AND MONDAY...VFR. TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE. WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR. FRIDAY...VFR. MTF && .MARINE... 300 PM CDT A COLD FRONT TRAILING FROM LOW PRESSURE INCHES IN EASTERN MANITOBA WILL MOVE EAST ACROSS LAKE MICHIGAN LATE THIS AFTERNOON AND EARLY THIS EVENING SHIFTING WINDS TO OUT OF THE WEST AND NORTHWEST. THE LOW CONTINUES NORTH-NORTHEASTWARD TO SOUTHWESTERN HUDSON BAY TONIGHT AND HIGH PRESSURE MOVES NORTHEAST FROM THE CENTRAL HIGH PLAINS TO IOWA. NORTHWEST AND NORTH WINDS WILL DIMINISH SUNDAY AS THE HIGH CONTINUE TO THE NORTHEAST....REACHING THE UPPER GREAT LAKES BY MONDAY MORNING. LOW PRESSURE TRACKS NORTHEASTWARD FROM THE CENTRAL HIGH PLAINS TO IOWA MONDAY AND MONDAY NIGHT. IN RESPONSE WINDS ON LAKE MICHIGAN WILL VEER TO OUT OF THE EAST AND SOUTHEAST AND GRADUALLY INCREASE. THIS LOW WILL MOVE ACROSS WISCONSIN AND CENTRAL LAKE MICHIGAN DURING TUESDAY AND TUESDAY NIGHT...AND THEN ON ACROSS ONTARIO TO WESTERN QUEBEC WEDNESDAY AND THURSDAY. TRS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
254 PM CDT SAT OCT 12 2013 .DISCUSSION... 253 PM CDT SYNOPSIS...A COLD FRONT CONTINUES TO SWING THROUGH THIS AFTERNOON WITH SCATTERED SHOWERS AND ISOLATED THUNDER ALONG IT. DRY WEATHER AND SEASONAL TEMPS ARE EXPECTED EARLY NEXT WEEK WITH ANOTHER LOW BRINGING SHOWERS AND SOME STORMS TUESDAY AND LINGERING SHOWERS ON WEDNESDAY. BELOW NORMAL TEMPS AND DRY WEATHER ARE THEN EXPECTED LATE NEXT WEEK. REST OF TODAY AND TONIGHT... THE COLD FRONT CURRENTLY STRETCHES FROM GREEN BAY TO AURORA TO CHAMPAIGN AND IT WILL CONTINUE EAST INTO THIS EVENING. STILL ONLY EXPECTING SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS ALONG THE FRONT...AND WINDS WILL TURN WEST AND GUST TO AROUND 20 KT BEHIND IT. INSTABILITY IS WEAK ALONG THE FRONT WITH THE LATEST RAP ANALYSIS SUGGESTING MAX CAPE VALUES OF 500 J/KG. THE BETTER SHOWER AND STORM COVERAGE WILL BE NORTH OF OUR CWA ASSOCIATED WITH A SHORTWAVE MOVING INTO WI. THAT BEING SAID A BRIEF MODERATE TO HEAVY SHOWER IS POSSIBLE AS PWAT VALUES ARE AROUND 1.2 INCHES THIS AFTN. HEAVIER SHOWERS COULD LOWER VISIBILITIES TO 1 TO 3 MILES. TEMPS WILL FALL UNDER THE SHOWERS...BUT PLACES OUT WEST ARE EXPECTED TO WARM A BIT AS THE SUN BREAKS OUT AGAIN. LOWERED LOW TEMPS FOR TONIGHT GIVEN THAT WINDS WILL BE DIMINISHING AND CLEAR SKIES. WENT A COUPLE OF DEGREES ABOVE THE MIN DEWPOINT...BUT WONDERING IF SOME ISOLATED AREAS WILL DROP A BIT LOWER THAN FORECAST. SUNDAY AND MONDAY... THE UPPER LEVEL PATTERN BECOMES ZONAL BEHIND THE UPPER LEVEL TROUGH TOMORROW WITH WEAK RIDGING ALOFT SUNDAY NIGHT INTO MONDAY. A SURFACE HIGH MOVES OVER THE REGION TOMORROW AND CONTINUES EAST REACHING SOUTHERN QUEBEC BY TUESDAY MORNING. SUNDAY LOOKS PLEASANT WITH SEASONAL TEMPS IN THE 60S...COOLER BY THE LAKE DUE TO ONSHORE FLOW. WINDS TURN SOUTHEAST MONDAY WITH TEMPS A BIT WARMER IN THE MID 60S TO AROUND 70 SOUTH. TUESDAY AND WEDNESDAY... AN UPPER LEVEL TROUGH CURRENTLY OVER NEVADA WILL MOVE OVER THE NORTHERN PLAINS MONDAY NIGHT AS A CLOSED LOW. IT WILL REMAIN RELATIVELY STATIONARY TUESDAY BEFORE MOVING OVER THE NORTHERN MISSISSIPPI RIVER VALLEY TUESDAY OR TUESDAY NIGHT. THE BLOCKING LOW CURRENTLY OFF THE THE CENTRAL ATLANTIC COAST SLOWLY WEAKENS AND SHIFTS SOUTH EARLY NEXT WEEK...WHICH WILL ONCE AGAIN RESULT IN A SLOWLY MOVING LOW THAT PASSES TO OUR NORTHWEST. IN GENERAL THE GFS AND NAM ARE MUCH FASTER THAN OTHER GUIDANCE WITH THE LOW...AND WILL BASE THE FORECAST OFF OF THE SLOWER ECMWF PER THE WPC GUIDANCE EVALUATION. THE ASSOCIATED SURFACE LOW WILL ALSO BEGIN OVER THE NORTHERN PLAINS BUT A BIT MORE TO THE EAST...AND THE LOW REMAINS NEGATIVELY STACKED WITH HEIGHT THROUGH THE END OF THE WEEK. THE LOW ALSO HAS JET SUPPORT AS THE UPPER LEVEL JET STRENGTHENS WEDNESDAY WHILE THE LOW IS IN THE FAVORABLE LEFT EXIT REGION. THE SURFACE LOW BEGINS TO CROSS THE MISSISSIPPI RIVER VALLEY TUESDAY WITH ITS WARM FRONT LIFTING THROUGH THE CWA TUESDAY AFTERNOON. EXPECTING SHOWERS AND A FEW STORMS AHEAD OF AND ALONG THE FRONT TUESDAY WITH A BETTER CHANCE OF STORMS TUESDAY AFTERNOON. INSTABILITY IS WEAK TUESDAY SO KEPT JUST A CHANCE OF TS GOING...WITH AFTN CAPE VALUES FORECAST TO BE 500 J/KG OR LESS. MOISTURE HOWEVER WILL NOT BE AN ISSUE...WITH PWATS OF 1-1.5 INCHES. THE LOWS COLD FRONT SWINGS THROUGH TUESDAY EVENING/NIGHT WITH ADDITIONAL SHOWERS EXPECTED INTO WEDNESDAY. GUIDANCE STILL SUGGESTS THE DRY SLOT WILL LEAD TO A FEW DRY HOURS WEDNESDAY AFTERNOON BEFORE SOME LIGHT WRAP AROUND PRECIP MOVES IN WEDNESDAY NIGHT. THE LOW WILL BE MOVING OFF TO THE NE AT THIS TIME SO WILL KEEP SLIGHT CHANCE OF PRECIP MAINLY ALONG THE IL/WI STATE LINE. FOR TEMPS...EXPECTING A BRIEF WARM UP TUESDAY INTO THE UPPER 60S AND 70S AS WE ARE IN THE WARM SECTOR OF THE LOW. THEN BACK TO REALITY WEDNESDAY WITH MORE SEASONAL TEMPS IN THE UPPER 50S TO LOW 60S. EXTENDED...THURSDAY AND FRIDAY... GUIDANCE INDICATES A SHORTWAVE WILL MOVE OVER THE CWA THURSDAY...HOWEVER GUIDANCE DIFFERS ON HOW MUCH MOISTURE WILL BE ASSOCIATED WITH THE DISTURBANCE. GIVEN THE DIFFERENCES AND WHERE THE SHORTWAVE MOVES THROUGH THE CWA...WENT WITH A DRY FORECAST FOR THURSDAY. FRIDAY ALSO LOOKS DRY WITH A COOLING TREND AS AN UPPER LEVEL TROUGH APPROACHES FROM THE EAST. HOWEVER...THE JET REMAINS OVERHEAD KEEPING THE MUCH COOLER AIR TO OUR NORTH. IN GENERAL HAVE BELOW NORMAL TEMPS IN FOR LATE THIS WEEK...AND NEXT WEEKEND IS STILL LOOKING COLD AS PREVIOUSLY ADVERTISED. JEE && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * A 30-45 MIN PERIOD OF TSRA AT/NEAR ORD AND POTENTIALLY MDW PRIOR TO 20Z. * MVFR CIGS THIS AFTERNOON...INCLUDING FOR A 2-3 HR PERIOD AFTER THE SHRA/TSRA. BRIEF CIGS AROUND 1500 FT POSSIBLE. * WIND SHIFT TO WSW AND EVENTUALLY W OR WNW BETWEEN 23Z AND 01Z. * WINDS TURNING NE DURING SUNDAY AFTERNOON. //DISCUSSION...UPDATED 18Z... A COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD ACROSS NORTHERN IL AND NORTHWEST IN THROUGH THE AFTERNOON. AHEAD OF THIS...SCATTERED SHOWERS WILL CONTINUE. A MORE DEFINED AXIS OF SHOWERS AND EMBEDDED STORMS FROM SE WI THROUGH MORRIS WILL LIKELY HOLD TOGETHER AS IT MOVES NORTHEAST AND IS THE REASON FOR THE TEMPO OF TSRA AT ORD. WHILE IT IS TWO HOURS...THE WINDOW OF TIME FOR THUNDER IS LIKELY 45 MIN OR LESS /IT JUST HAPPENS TO SPLIT THE 19Z HOUR/. WINDS SHOULD MAINTAIN SSW THROUGH THE STORMS...AND IF THE STORMS DO SHIFT THE WINDS IT WOULD ONLY BE SLIGHTLY TO SW. MOISTURE ALONG THE FRONT WILL KEEP MVFR CIGS IN PLACE BEHIND THE SHRA/TSRA FOR A 2-3 HOUR WINDOW WITH A FEW SITES IN WESTERN IL INDICATING CIGS AT OR BELOW 1500 FT...BUT THAT LOW OF CIG WILL NOT LAST LONG IF IT OCCURS. AFTER FRONTAL PASSAGE LATE THIS AFTERNOON WINDS WILL TURN W TO WNW AND THE SKY WILL CLEAR. THE GRADIENT WILL EASE ENOUGH ON SUNDAY TO LIKELY ALLOW WINDS TO TURN NE OFF OF LAKE MICHIGAN AT ORD AND MDW...AND AT THIS POINT THAT SEEMS MOST FAVORED IN THE EARLY AFTERNOON. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN SHRA TIMING AND MEDIUM CONFIDENCE IN TSRA OCCURRING AT ORD. HIGH CONFIDENCE IN TSRA AT LEAST NEARBY. * HIGH CONFIDENCE IN MVFR CIGS AT ORD AND MEDIUM CONFIDENCE AT MDW. HIGH CONFIDENCE THAT IF CIGS DROP TO 1500 FT IT WILL BE BRIEF /LIKELY UNDER ONE HOUR/. * HIGH CONFIDENCE IN WSW WINDS BY 23Z. * MEDIUM CONFIDENCE ON EARLY AFTERNOON TIMING OF WINDS TURNING NE ON SUNDAY. //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT AND MONDAY...VFR. TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE. WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR. FRIDAY...VFR. MTF && .MARINE... 125 AM CDT DEEP LOW PRESSURE SYSTEM OF 991 MB WAS OVER FAR NORTHEASTERN NORTH DAKOTA EARLY THIS MORNING...AND WILL CONTINUE TO LIFT NORTH ACROSS FAR EASTERN MANITOBA AND SLOWLY FILL THROUGH THIS EVENING. SURFACE PRESSURE FALLS ASSOCIATED WITH THIS FEATURE ACROSS ONTARIO AND THE NORTHERN GREAT LAKES WILL RESULT IN SOUTH WINDS PICKING UP INTO THE 20-25 KT RANGE ESPECIALLY ACROSS NORTHERN LAKE MICHIGAN TODAY...WITH 30 KTS NOT TOO FAR ABOVE THE THERMALLY STABLE MARINE LAYER. THE COLD FRONT TRAILING FROM THE LOW WILL MOVE EAST ACROSS THE LAKE THIS AFTERNOON...SHIFTING WINDS INITIALLY TO THE WEST-SOUTHWEST AND EVENTUALLY MORE NORTHWEST TONIGHT. FORECAST SOUNDINGS FROM SEVERAL MODELS INDICATE THAT THE MIXED LAYER WILL DEEPEN BEHIND THE FRONT BY THIS EVENING AS COOL ADVECTION STEEPENS LAPSE RATES OVER THE WATER...WHICH MAY THEN ALLOW FOR 30 KT GUSTS THIS EVENING ESPECIALLY NORTH AS THE LOW CONTINUES TO PULL AWAY. HIGH PRESSURE THEN BUILDS QUICKLY INTO THE REGION SUNDAY...ALLOWING A QUICK DECREASE IN WINDS AS THE RIDGE APPROACHES. THE SURFACE RIDGE WILL MOVE EAST OF LAKE MICHIGAN SUNDAY NIGHT...WITH A NEW AREA OF LOW PRESSURE EXPECTED TO DEVELOP ACROSS THE CENTRAL HIGH PLAINS BY MONDAY MORNING. WHILE SOME DETAILS DIFFER BETWEEN MODEL RUNS...THIS LOW IS BASICALLY FORECAST TO MOVE NORTHEAST ACROSS IOWA/MINNESOTA MONDAY NIGHT AND TUESDAY BEFORE CROSSING CENTRAL OR NORTHERN LAKE MICHIGAN TUESDAY NIGHT INTO WEDNESDAY. THIS WILL LIKELY RESULT IN EAST-SOUTHEAST WINDS DEVELOPING AHEAD OF THE LOW AND INCREASING ESPECIALLY MONDAY NIGHT WITH GUSTS POTENTIALLY IN THE 20-25 KT RANGE. THE GRADIENT WILL THEN WEAKEN BY LATE TUESDAY AS THE LOW CROSSES THE LAKE. DETAILS IN FORECAST WIND SPEED AND DIRECTION WILL HAVE TO BE FINE TUNED AS THE TRACK OF THE SURFACE LOW BECOMES MORE CERTAIN. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1248 PM CDT SAT OCT 12 2013 .DISCUSSION... 1015 AM CDT MINOR TWEAKS MADE TO GOING FORECAST. THE GENERAL TREND CONTINUES HOWEVER WITH ISOLATED/SCATTERED SHOWERS AND A FEW STORMS AT MOST MOVING EAST...ALONG WITH HIGHS MAINLY IN THE LOWER TO MID 70S...WITH A FEW PLACES IN NORTH CENTRAL IL LIKELY TO TOP OUT ONLY IN THE UPPER 60S. THE MID-LEVEL TROUGH CENTERED ACROSS THE UPPER MIDWEST CONTINUES TO SEE A NARROW DEEP MOIST PLUME AHEAD OF ITS HEIGHT FALLS...AND THAT AXIS IS MOVING ACROSS THE AREA. THIS CORRIDOR BASICALLY DEFINES WHERE SHOWERS ARE POSSIBLE AS THE COLUMN IS SIMPLY TOO DRY ELSEWHERE. THE LEADING EDGE OF SHOWERS AND ISOLATED STORMS HAS WEAKENED SINCE EARLY MORNING WITH A DECAY OF THE LLJ/MOISTURE TRANSPORT. WOULD EXPECT TO STILL SEE A COVERAGE RE-INCREASE IN SHOWERS EAST OF THE I-55 CORRIDOR AS MID-LEVEL JET AND SHEARED SHORT WAVE ACROSS CENTRAL MO PROGRESSES NORTHEAST AND PROVIDES SLIGHTLY MORE FORCING. THE SURFACE FRONT ALREADY IS KNOCKING ON THE DOOR OF THE WESTERN FORECAST AREA AND JUST OVERALL IMPROVED CONVERGENCE COULD HELP AN INCREASE IN SOME SHOWERS THE NEXT FEW HOURS AS WELL. THE 12Z DVN SOUNDING HAD STEEP LAPSE RATES FROM 850-700MB YIELDING TOTAL TOTAL AND K-INDEX VALUES SUPPORTIVE OF ISOLATED THUNDER AND WE DID SEE THAT EARLIER. RAP INDICATIONS ARE FOR THE SAME AMOUNT OF INSTABILITY TO EVOLVE EAST SO WE MAINTAIN THE SLIGHT CHANCE OF THUNDER. TEMPERATURES ARE BATTLING CLOUD COVER IN NORTH CENTRAL IL. WITH FROPA OCCURRING THERE IN THE NEXT FEW HOURS...TEMPERATURES WILL NOT HAVE TOO MUCH LONGER TO RECOVER ESPECIALLY WITH SOME POST-FRONTAL LOW CLOUDS FOR A COUPLE HOURS. SO DID INCH DOWN FORECAST MAXS THERE SOMEWHAT . IT LOOKS LIKE TEMPS MAY DROP A DEGREE OR TWO WITH FROPA OR BASICALLY HOLD STEADY. THE EASTERN FORECAST AREA...ESPECIALLY NORTHWEST IN...WILL CONTINUE TO WARM PRIOR TO THE SCATTERED SHOWER ARRIVAL. MTF //PREV DISCUSSION... 256 AM CDT TODAY... THIS MORNING...A CLOSED UPPER LOW IN NOTED ON WATER VAPOR IMAGERY LIFTING NORTH INTO MANITOBA...WHILE A COMPACT SHORTWAVE IS ROTATING AROUND THE MAIN LOW...MOVING EAST ACROSS SOUTH DAKOTA. ANOTHER WAVE IS NOTED FARTHER SOUTH...LIFTING NORTHEAST ACROSS FAR EASTERN KANSAS. AT THE SURFACE...DEEP LOW PRESSURE IS ANALYZED OVER SOUTHERN MANITOBA WITH A COLD FRONT EXTENDING SOUTH INTO EASTERN IOWA. A FEW SHOWERS ARE NOTED ALONG THE FRONT...MAINLY AHEAD OF THE SOUTHERN WAVE...OTHERWISE THE FRONT HAS BEEN FAIRLY QUIET OVERNIGHT WITH ONLY A FEW SHOWERS ALONG IT. EXPECT SHOWERS ALONG THE FRONT TO INCREASE IN COVERAGE AROUND DAYBREAK THIS MORNING AS SOUTHERN SHORTWAVE APPROACHES THE AREA...THEN A BRIEF LULL MAY OCCUR ALONG THE FRONT AS THE WAVE DEPARTS MID MORNING. MEANWHILE...NORTHERN STREAM WAVE WILL ARRIVE OVER THE ARE MID AFTERNOON AS THE FRONT IS MOVING ACROSS THE HEART OF THE CWA. GUIDANCE STILL HINTING AT SOME VERY MODEST INSTABILITY...WITH LOW 60 DEWPOINTS POOLING ALONG THE FRONT. WITH THIS IN MIND...STILL CANNOT RULE OUT AN ISOLATED THUNDERSTORM OR TWO...BUT BY AND LARGE THE REGION STILL WILL BE SPLIT BY THE BETTER DYNAMIC FORCING TO THE NORTH AND BETTER INSTABILITY WELL SOUTH. SHOWERS WILL LIKELY BE TIED VERY CLOSELY TO AND SLIGHTLY AHEAD OF THE FRONT...SO THE ENTIRE DAY WILL NOT BE A WASH...WITH ONLY A COUPLE HOUR WINDOW WHERE SHOWERS MAY OCCUR AS THE FRONT SWEEPS OVERHEAD...THEN QUICKLY DRYING OUT BEHIND. TONIGHT THROUGH MONDAY NIGHT... PERIOD WILL BE DOMINATED BY A COOLER AND DRIER AIRMASS...AS HIGH PRESSURE BUILDS OVER THE MID MISSOURI VALLEY TONIGHT WHILE COLD ADVECTION INTO THE AREA ALLOWS H85 TEMPS FALL TO AROUND 4-5C BY DAYBREAK SUNDAY. UNDER CLEAR SKIES AND LIGHT WINDS...AREAS PARTICULARLY WEST OF THE FOX RIVER VALLEY SHOULD QUICKLY DECOUPLE ALLOWING TEMPS TO PLUMMET. BLENDED TOWARDS COOLER GUIDANCE...AND CONTINUE TO EXPECT SOME OF THE TYPICAL COOL SPOTS TO FALL INTO THE 30S...THOUGH THE URBAN HEAT ISLAND OF CHICAGO WILL HELP KEEP TEMPERATURES PROPPED UP AROUND 50 IN THE METRO AREA. FOR SUNDAY...CLIMATOLOGY SHOWS MEAN HIGH TEMPERATURES IN THE LOW TO MID 60S GIVEN THE H85 TEMPS...AND H92 TEMPS AROUND 14C. TEMPERATURES WILL LIKELY BE IN THE LOW 60S NEAR THE LAKE FRONT WHERE ONSHORE WINDS WILL KEEP TEMPERATURES A FEW DEGREES COOLER COMPARED TO INLAND. VERY DRY AIR ALOFT WILL BE MIXED DOWN TO THE SURFACE WITH DEWPOINTS EXPECTED TO FALL INTO THE LOW 30S WEST TO UPPER 30S EAST RESULTING IN RELATIVE HUMIDITY FALLING TO INTO THE 25 TO 35 PERCENT RANGE. CONDITIONS SHOULD BE MOSTLY UNCHANGED HEADING INTO SUNDAY NIGHT AS HIGH PRESSURE SHIFTS ENE OVER WISCONSIN. ONCE AGAIN... EXPECT TEMPERATURES TO RADIATE EFFICIENTLY...AND LEANED TOWARDS COOLER SIDE OF GUIDANCE. TEMPERATURES WILL REBOUND SOME MONDAY AS THE HIGH CONTINUES TO SHIFT EAST OVER NORTHERN MICHIGAN WITH RETURN FLOW AND WARM ADVECTION OVER SPREADING THE AREA. ALSO SHOULD SEE AN INCREASE IN HIGH AND MID LEVEL CLOUD COVER AS LOW PRESSURE MOVES EAST FROM THE COLORADO FRONT RANGE TO THE MID MISSOURI VALLEY. TUESDAY THROUGH FRIDAY... STRONG WAVE MOVING ONTO THE PACIFIC NORTHWEST COAST THIS MORNING WILL CARVE OUT A BROAD TROUGH OVER THE WESTERN CONUS BY TUESDAY WITH A CLOSED UPPER LOW FORMING OVER THE GREAT BASIN. THIS UPPER LOW WILL MOVE EAST INTO THE UPPER MIDWEST TUESDAY...WITH THE AFOREMENTIONED SURFACE LOW MOVING OVER WI/MN. WHILE THERE ARE STILL TIMING/TRACK DIFFERENCES THIS FAR OUT...OVERALL EVOLUTION OF THE SYSTEM IS FAIRLY SIMILAR BETWEEN MODELS. WARM ADVECTION/ISENTROPIC ASCENT WILL LEAD TO SHOWERS AHEAD OF THE LOW TUESDAY...WITH SHOWERS ALONG THE TRAILING COLD FRONT TUESDAY NIGHT. DEPENDING ON THE TRACK OF THE LOW...DRY SLOT WILL LEAD TO A LULL IN PRECIP BEFORE WRAP AROUND MOISTURE BEHIND THE LOW OVERSPREADS THE AREA ONCE AGAIN WEDNESDAY. PERIOD OF BELOW NORMAL TEMPS IS EXPECTED BEHIND THE SURFACE LOW TO END THE WORK WEEK AS THE OVERALL PATTERN REMAINS AMPLIFIED WITH A BROAD TROUGH SPANNING THE EASTERN CONUS. INTERESTINGLY..TAKING A PEAK INTO NEXT WEEKEND...BOTH THE 00Z ECMWF AND GFS SHOW A VERY COLD AIRMASS SETTLING OVER ONTARIO //H85 TEMPS DROPPING TO -10 TO -12C// WITH MODELS HINTING TO SOME DEGREE THAT THIS COLD AIR WILL MAKE A PUSH INTO THE GREAT LAKES REGION WITH SUB ZERO H85 TEMPS LOCALLY...WHICH IF IT PANS OUT WOULD MAY LEAD TO WELL BELOW NORMAL TEMPS WITH HIGHS POSSIBLY TOPPING OUT IN THE 40S. DEUBELBEISS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * A 30-45 MIN PERIOD OF TSRA AT/NEAR ORD AND POTENTIALLY MDW PRIOR TO 20Z. * MVFR CIGS THIS AFTERNOON...INCLUDING FOR A 2-3 HR PERIOD AFTER THE SHRA/TSRA. BRIEF CIGS AROUND 1500 FT POSSIBLE. * WIND SHIFT TO WSW AND EVENTUALLY W OR WNW BETWEEN 23Z AND 01Z. * WINDS TURNING NE DURING SUNDAY AFTERNOON. //DISCUSSION...UPDATED 18Z... A COLD FRONT WILL CONTINUE TO PROGRESS EASTWARD ACROSS NORTHERN IL AND NORTHWEST IN THROUGH THE AFTERNOON. AHEAD OF THIS...SCATTERED SHOWERS WILL CONTINUE. A MORE DEFINED AXIS OF SHOWERS AND EMBEDDED STORMS FROM SE WI THROUGH MORRIS WILL LIKELY HOLD TOGETHER AS IT MOVES NORTHEAST AND IS THE REASON FOR THE TEMPO OF TSRA AT ORD. WHILE IT IS TWO HOURS...THE WINDOW OF TIME FOR THUNDER IS LIKELY 45 MIN OR LESS /IT JUST HAPPENS TO SPLIT THE 19Z HOUR/. WINDS SHOULD MAINTAIN SSW THROUGH THE STORMS...AND IF THE STORMS DO SHIFT THE WINDS IT WOULD ONLY BE SLIGHTLY TO SW. MOISTURE ALONG THE FRONT WILL KEEP MVFR CIGS IN PLACE BEHIND THE SHRA/TSRA FOR A 2-3 HOUR WINDOW WITH A FEW SITES IN WESTERN IL INDICATING CIGS AT OR BELOW 1500 FT...BUT THAT LOW OF CIG WILL NOT LAST LONG IF IT OCCURS. AFTER FRONTAL PASSAGE LATE THIS AFTERNOON WINDS WILL TURN W TO WNW AND THE SKY WILL CLEAR. THE GRADIENT WILL EASE ENOUGH ON SUNDAY TO LIKELY ALLOW WINDS TO TURN NE OFF OF LAKE MICHIGAN AT ORD AND MDW...AND AT THIS POINT THAT SEEMS MOST FAVORED IN THE EARLY AFTERNOON. //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN SHRA TIMING AND MEDIUM CONFIDENCE IN TSRA OCCURRING AT ORD. HIGH CONFIDENCE IN TSRA AT LEAST NEARBY. * HIGH CONFIDENCE IN MVFR CIGS AT ORD AND MEDIUM CONFIDENCE AT MDW. HIGH CONFIDENCE THAT IF CIGS DROP TO 1500 FT IT WILL BE BRIEF /LIKELY UNDER ONE HOUR/. * HIGH CONFIDENCE IN WSW WINDS BY 23Z. * MEDIUM CONFIDENCE ON EARLY AFTERNOON TIMING OF WINDS TURNING NE ON SUNDAY. //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT AND MONDAY...VFR. TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE. WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR. FRIDAY...VFR. MTF && .MARINE... 125 AM CDT DEEP LOW PRESSURE SYSTEM OF 991 MB WAS OVER FAR NORTHEASTERN NORTH DAKOTA EARLY THIS MORNING...AND WILL CONTINUE TO LIFT NORTH ACROSS FAR EASTERN MANITOBA AND SLOWLY FILL THROUGH THIS EVENING. SURFACE PRESSURE FALLS ASSOCIATED WITH THIS FEATURE ACROSS ONTARIO AND THE NORTHERN GREAT LAKES WILL RESULT IN SOUTH WINDS PICKING UP INTO THE 20-25 KT RANGE ESPECIALLY ACROSS NORTHERN LAKE MICHIGAN TODAY...WITH 30 KTS NOT TOO FAR ABOVE THE THERMALLY STABLE MARINE LAYER. THE COLD FRONT TRAILING FROM THE LOW WILL MOVE EAST ACROSS THE LAKE THIS AFTERNOON...SHIFTING WINDS INITIALLY TO THE WEST-SOUTHWEST AND EVENTUALLY MORE NORTHWEST TONIGHT. FORECAST SOUNDINGS FROM SEVERAL MODELS INDICATE THAT THE MIXED LAYER WILL DEEPEN BEHIND THE FRONT BY THIS EVENING AS COOL ADVECTION STEEPENS LAPSE RATES OVER THE WATER...WHICH MAY THEN ALLOW FOR 30 KT GUSTS THIS EVENING ESPECIALLY NORTH AS THE LOW CONTINUES TO PULL AWAY. HIGH PRESSURE THEN BUILDS QUICKLY INTO THE REGION SUNDAY...ALLOWING A QUICK DECREASE IN WINDS AS THE RIDGE APPROACHES. THE SURFACE RIDGE WILL MOVE EAST OF LAKE MICHIGAN SUNDAY NIGHT...WITH A NEW AREA OF LOW PRESSURE EXPECTED TO DEVELOP ACROSS THE CENTRAL HIGH PLAINS BY MONDAY MORNING. WHILE SOME DETAILS DIFFER BETWEEN MODEL RUNS...THIS LOW IS BASICALLY FORECAST TO MOVE NORTHEAST ACROSS IOWA/MINNESOTA MONDAY NIGHT AND TUESDAY BEFORE CROSSING CENTRAL OR NORTHERN LAKE MICHIGAN TUESDAY NIGHT INTO WEDNESDAY. THIS WILL LIKELY RESULT IN EAST-SOUTHEAST WINDS DEVELOPING AHEAD OF THE LOW AND INCREASING ESPECIALLY MONDAY NIGHT WITH GUSTS POTENTIALLY IN THE 20-25 KT RANGE. THE GRADIENT WILL THEN WEAKEN BY LATE TUESDAY AS THE LOW CROSSES THE LAKE. DETAILS IN FORECAST WIND SPEED AND DIRECTION WILL HAVE TO BE FINE TUNED AS THE TRACK OF THE SURFACE LOW BECOMES MORE CERTAIN. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1107 AM CDT SAT OCT 12 2013 .DISCUSSION... 1015 AM CDT MINOR TWEAKS MADE TO GOING FORECAST. THE GENERAL TREND CONTINUES HOWEVER WITH ISOLATED/SCATTERED SHOWERS AND A FEW STORMS AT MOST MOVING EAST...ALONG WITH HIGHS MAINLY IN THE LOWER TO MID 70S...WITH A FEW PLACES IN NORTH CENTRAL IL LIKELY TO TOP OUT ONLY IN THE UPPER 60S. THE MID-LEVEL TROUGH CENTERED ACROSS THE UPPER MIDWEST CONTINUES TO SEE A NARROW DEEP MOIST PLUME AHEAD OF ITS HEIGHT FALLS...AND THAT AXIS IS MOVING ACROSS THE AREA. THIS CORRIDOR BASICALLY DEFINES WHERE SHOWERS ARE POSSIBLE AS THE COLUMN IS SIMPLY TOO DRY ELSEWHERE. THE LEADING EDGE OF SHOWERS AND ISOLATED STORMS HAS WEAKENED SINCE EARLY MORNING WITH A DECAY OF THE LLJ/MOISTURE TRANSPORT. WOULD EXPECT TO STILL SEE A COVERAGE RE-INCREASE IN SHOWERS EAST OF THE I-55 CORRIDOR AS MID-LEVEL JET AND SHEARED SHORT WAVE ACROSS CENTRAL MO PROGRESSES NORTHEAST AND PROVIDES SLIGHTLY MORE FORCING. THE SURFACE FRONT ALREADY IS KNOCKING ON THE DOOR OF THE WESTERN FORECAST AREA AND JUST OVERALL IMPROVED CONVERGENCE COULD HELP AN INCREASE IN SOME SHOWERS THE NEXT FEW HOURS AS WELL. THE 12Z DVN SOUNDING HAD STEEP LAPSE RATES FROM 850-700MB YIELDING TOTAL TOTAL AND K-INDEX VALUES SUPPORTIVE OF ISOLATED THUNDER AND WE DID SEE THAT EARLIER. RAP INDICATIONS ARE FOR THE SAME AMOUNT OF INSTABILITY TO EVOLVE EAST SO WE MAINTAIN THE SLIGHT CHANCE OF THUNDER. TEMPERATURES ARE BATTLING CLOUD COVER IN NORTH CENTRAL IL. WITH FROPA OCCURRING THERE IN THE NEXT FEW HOURS...TEMPERATURES WILL NOT HAVE TOO MUCH LONGER TO RECOVER ESPECIALLY WITH SOME POST-FRONTAL LOW CLOUDS FOR A COUPLE HOURS. SO DID INCH DOWN FORECAST MAXS THERE SOMEWHAT . IT LOOKS LIKE TEMPS MAY DROP A DEGREE OR TWO WITH FROPA OR BASICALLY HOLD STEADY. THE EASTERN FORECAST AREA...ESPECIALLY NORTHWEST IN...WILL CONTINUE TO WARM PRIOR TO THE SCATTERED SHOWER ARRIVAL. MTF //PREV DISCUSSION... 256 AM CDT TODAY... THIS MORNING...A CLOSED UPPER LOW IN NOTED ON WATER VAPOR IMAGERY LIFTING NORTH INTO MANITOBA...WHILE A COMPACT SHORTWAVE IS ROTATING AROUND THE MAIN LOW...MOVING EAST ACROSS SOUTH DAKOTA. ANOTHER WAVE IS NOTED FARTHER SOUTH...LIFTING NORTHEAST ACROSS FAR EASTERN KANSAS. AT THE SURFACE...DEEP LOW PRESSURE IS ANALYZED OVER SOUTHERN MANITOBA WITH A COLD FRONT EXTENDING SOUTH INTO EASTERN IOWA. A FEW SHOWERS ARE NOTED ALONG THE FRONT...MAINLY AHEAD OF THE SOUTHERN WAVE...OTHERWISE THE FRONT HAS BEEN FAIRLY QUIET OVERNIGHT WITH ONLY A FEW SHOWERS ALONG IT. EXPECT SHOWERS ALONG THE FRONT TO INCREASE IN COVERAGE AROUND DAYBREAK THIS MORNING AS SOUTHERN SHORTWAVE APPROACHES THE AREA...THEN A BRIEF LULL MAY OCCUR ALONG THE FRONT AS THE WAVE DEPARTS MID MORNING. MEANWHILE...NORTHERN STREAM WAVE WILL ARRIVE OVER THE ARE MID AFTERNOON AS THE FRONT IS MOVING ACROSS THE HEART OF THE CWA. GUIDANCE STILL HINTING AT SOME VERY MODEST INSTABILITY...WITH LOW 60 DEWPOINTS POOLING ALONG THE FRONT. WITH THIS IN MIND...STILL CANNOT RULE OUT AN ISOLATED THUNDERSTORM OR TWO...BUT BY AND LARGE THE REGION STILL WILL BE SPLIT BY THE BETTER DYNAMIC FORCING TO THE NORTH AND BETTER INSTABILITY WELL SOUTH. SHOWERS WILL LIKELY BE TIED VERY CLOSELY TO AND SLIGHTLY AHEAD OF THE FRONT...SO THE ENTIRE DAY WILL NOT BE A WASH...WITH ONLY A COUPLE HOUR WINDOW WHERE SHOWERS MAY OCCUR AS THE FRONT SWEEPS OVERHEAD...THEN QUICKLY DRYING OUT BEHIND. TONIGHT THROUGH MONDAY NIGHT... PERIOD WILL BE DOMINATED BY A COOLER AND DRIER AIRMASS...AS HIGH PRESSURE BUILDS OVER THE MID MISSOURI VALLEY TONIGHT WHILE COLD ADVECTION INTO THE AREA ALLOWS H85 TEMPS FALL TO AROUND 4-5C BY DAYBREAK SUNDAY. UNDER CLEAR SKIES AND LIGHT WINDS...AREAS PARTICULARLY WEST OF THE FOX RIVER VALLEY SHOULD QUICKLY DECOUPLE ALLOWING TEMPS TO PLUMMET. BLENDED TOWARDS COOLER GUIDANCE...AND CONTINUE TO EXPECT SOME OF THE TYPICAL COOL SPOTS TO FALL INTO THE 30S...THOUGH THE URBAN HEAT ISLAND OF CHICAGO WILL HELP KEEP TEMPERATURES PROPPED UP AROUND 50 IN THE METRO AREA. FOR SUNDAY...CLIMATOLOGY SHOWS MEAN HIGH TEMPERATURES IN THE LOW TO MID 60S GIVEN THE H85 TEMPS...AND H92 TEMPS AROUND 14C. TEMPERATURES WILL LIKELY BE IN THE LOW 60S NEAR THE LAKE FRONT WHERE ONSHORE WINDS WILL KEEP TEMPERATURES A FEW DEGREES COOLER COMPARED TO INLAND. VERY DRY AIR ALOFT WILL BE MIXED DOWN TO THE SURFACE WITH DEWPOINTS EXPECTED TO FALL INTO THE LOW 30S WEST TO UPPER 30S EAST RESULTING IN RELATIVE HUMIDITY FALLING TO INTO THE 25 TO 35 PERCENT RANGE. CONDITIONS SHOULD BE MOSTLY UNCHANGED HEADING INTO SUNDAY NIGHT AS HIGH PRESSURE SHIFTS ENE OVER WISCONSIN. ONCE AGAIN... EXPECT TEMPERATURES TO RADIATE EFFICIENTLY...AND LEANED TOWARDS COOLER SIDE OF GUIDANCE. TEMPERATURES WILL REBOUND SOME MONDAY AS THE HIGH CONTINUES TO SHIFT EAST OVER NORTHERN MICHIGAN WITH RETURN FLOW AND WARM ADVECTION OVER SPREADING THE AREA. ALSO SHOULD SEE AN INCREASE IN HIGH AND MID LEVEL CLOUD COVER AS LOW PRESSURE MOVES EAST FROM THE COLORADO FRONT RANGE TO THE MID MISSOURI VALLEY. TUESDAY THROUGH FRIDAY... STRONG WAVE MOVING ONTO THE PACIFIC NORTHWEST COAST THIS MORNING WILL CARVE OUT A BROAD TROUGH OVER THE WESTERN CONUS BY TUESDAY WITH A CLOSED UPPER LOW FORMING OVER THE GREAT BASIN. THIS UPPER LOW WILL MOVE EAST INTO THE UPPER MIDWEST TUESDAY...WITH THE AFOREMENTIONED SURFACE LOW MOVING OVER WI/MN. WHILE THERE ARE STILL TIMING/TRACK DIFFERENCES THIS FAR OUT...OVERALL EVOLUTION OF THE SYSTEM IS FAIRLY SIMILAR BETWEEN MODELS. WARM ADVECTION/ISENTROPIC ASCENT WILL LEAD TO SHOWERS AHEAD OF THE LOW TUESDAY...WITH SHOWERS ALONG THE TRAILING COLD FRONT TUESDAY NIGHT. DEPENDING ON THE TRACK OF THE LOW...DRY SLOT WILL LEAD TO A LULL IN PRECIP BEFORE WRAP AROUND MOISTURE BEHIND THE LOW OVERSPREADS THE AREA ONCE AGAIN WEDNESDAY. PERIOD OF BELOW NORMAL TEMPS IS EXPECTED BEHIND THE SURFACE LOW TO END THE WORK WEEK AS THE OVERALL PATTERN REMAINS AMPLIFIED WITH A BROAD TROUGH SPANNING THE EASTERN CONUS. INTERESTINGLY..TAKING A PEAK INTO NEXT WEEKEND...BOTH THE 00Z ECMWF AND GFS SHOW A VERY COLD AIRMASS SETTLING OVER ONTARIO //H85 TEMPS DROPPING TO -10 TO -12C// WITH MODELS HINTING TO SOME DEGREE THAT THIS COLD AIR WILL MAKE A PUSH INTO THE GREAT LAKES REGION WITH SUB ZERO H85 TEMPS LOCALLY...WHICH IF IT PANS OUT WOULD MAY LEAD TO WELL BELOW NORMAL TEMPS WITH HIGHS POSSIBLY TOPPING OUT IN THE 40S. DEUBELBEISS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 16Z... * SCATTERED SHOWERS FROM 1730Z-2000Z WITH A CHANCE FOR ISOLATED THUNDER. * A LIKELY 2-3 HOUR PERIOD OF 1700-2500 FT CIGS BEHIND THE SHOWERS DURING THE MID TO LATE AFTERNOON. * WIND SHIFT FROM S TO WSW LATE THIS AFTERNOON WITH COLD FRONTAL PASSAGE. A SHIFT TO NORTHERLY IS EXPECTED SUNDAY MORNING. MDB/MTF //DISCUSSION...UPDATED 12Z... STRONG LOW PRESSURE IS MOVING NORTH-NORTHEAST ACROSS FAR SOUTHEAST MANITOBA HAS A COLD FRONTAL BOUNDARY STRETCHING SOUTHWARD FROM IT WHICH IS JUST NOW REACHING THE MISSISSIPPI RIVER NEAR THE QUAD CITIES. SEVERAL WEAK WAVES APPEAR TO BE EMBEDDED IN THE UPPER FLOW PATTERN. A NARROW BAND OF SHOWERS HAS DEVELOPED OUT AHEAD OF THE FRONT IN CONJUNCTION WITH THE ACTIVE UPPER FLOW. THE EASTWARD PUSH OF THIS BAND HAS BEEN SLOW BUT IT LOOKS TO CONTINUE THROUGH THE MORNING. THE FRONT WILL TRY TO CATCH UP TO THE UPPER FORCING THROUGH THE DAY SO ANY GAP BETWEEN THE CURRENT ACTIVITY NEAR RFD AND ACTIVITY NEAR THE FRONT TO THE WEST MAY CLOSE WITH TIME. WILL CONTINUE WITH A FEW HOURS OF TEMPO SHOWERS ACROSS THE TERMINALS INTO THE AFTERNOON. STILL CANNOT RULE OUT THUNDER BUT THUNDER COVERAGE LOOKS TO BE ISOLATED OVER THE AREA WITH THE THREAT TOO LOW TO MENTION IN THE TAFS AT THIS TIME. BRIEF MVFR CIGS MAY ACCOMPANY THE FRONTAL PASSAGE BUT THESE LOOKS TO BE SHORT LIVED SO WILL CARRY PREVAILING LOWER END VFR CLOUD COVER. SOUTH-SOUTHEAST WINDS WILL INCREASE IN SPEED WITH TIME THIS MORNING AND TURN MORE SOUTH OR EVEN SOUTH-SOUTHWEST BEFORE TURNING SOUTHWEST THEN WEST WITH THE APPROACH AND PASSAGE OF THE FRONT THROUGH THE AFTERNOON. SPEEDS WILL EASE UP OVERNIGHT AS HIGH PRESSURE ARRIVES KEEPING QUIET WEATHER IN PLACE. WINDS WILL THEN TURN MORE NORTHERLY SUNDAY MORNING. MDB //ORD AND MDW CONFIDENCE...UPDATED 16Z... * HIGH CONFIDENCE IN SCATTERED SHOWERS WITH ISOLATED THUNDER IN THE AREA THROUGH 20Z. * MEDIUM CONFIDENCE IF MVFR CIGS TIMING AFTER THE SHOWERS BUT LOW CONFIDENCE IN THEM STAYING ABOVE 1500 FT. * HIGH CONFIDENCE IN WIND TRENDS. MDB/MTF //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT AND MONDAY...VFR. TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE. WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR. FRIDAY...VFR. && .MARINE... 125 AM CDT DEEP LOW PRESSURE SYSTEM OF 991 MB WAS OVER FAR NORTHEASTERN NORTH DAKOTA EARLY THIS MORNING...AND WILL CONTINUE TO LIFT NORTH ACROSS FAR EASTERN MANITOBA AND SLOWLY FILL THROUGH THIS EVENING. SURFACE PRESSURE FALLS ASSOCIATED WITH THIS FEATURE ACROSS ONTARIO AND THE NORTHERN GREAT LAKES WILL RESULT IN SOUTH WINDS PICKING UP INTO THE 20-25 KT RANGE ESPECIALLY ACROSS NORTHERN LAKE MICHIGAN TODAY...WITH 30 KTS NOT TOO FAR ABOVE THE THERMALLY STABLE MARINE LAYER. THE COLD FRONT TRAILING FROM THE LOW WILL MOVE EAST ACROSS THE LAKE THIS AFTERNOON...SHIFTING WINDS INITIALLY TO THE WEST-SOUTHWEST AND EVENTUALLY MORE NORTHWEST TONIGHT. FORECAST SOUNDINGS FROM SEVERAL MODELS INDICATE THAT THE MIXED LAYER WILL DEEPEN BEHIND THE FRONT BY THIS EVENING AS COOL ADVECTION STEEPENS LAPSE RATES OVER THE WATER...WHICH MAY THEN ALLOW FOR 30 KT GUSTS THIS EVENING ESPECIALLY NORTH AS THE LOW CONTINUES TO PULL AWAY. HIGH PRESSURE THEN BUILDS QUICKLY INTO THE REGION SUNDAY...ALLOWING A QUICK DECREASE IN WINDS AS THE RIDGE APPROACHES. THE SURFACE RIDGE WILL MOVE EAST OF LAKE MICHIGAN SUNDAY NIGHT...WITH A NEW AREA OF LOW PRESSURE EXPECTED TO DEVELOP ACROSS THE CENTRAL HIGH PLAINS BY MONDAY MORNING. WHILE SOME DETAILS DIFFER BETWEEN MODEL RUNS...THIS LOW IS BASICALLY FORECAST TO MOVE NORTHEAST ACROSS IOWA/MINNESOTA MONDAY NIGHT AND TUESDAY BEFORE CROSSING CENTRAL OR NORTHERN LAKE MICHIGAN TUESDAY NIGHT INTO WEDNESDAY. THIS WILL LIKELY RESULT IN EAST-SOUTHEAST WINDS DEVELOPING AHEAD OF THE LOW AND INCREASING ESPECIALLY MONDAY NIGHT WITH GUSTS POTENTIALLY IN THE 20-25 KT RANGE. THE GRADIENT WILL THEN WEAKEN BY LATE TUESDAY AS THE LOW CROSSES THE LAKE. DETAILS IN FORECAST WIND SPEED AND DIRECTION WILL HAVE TO BE FINE TUNED AS THE TRACK OF THE SURFACE LOW BECOMES MORE CERTAIN. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1016 AM CDT SAT OCT 12 2013 .DISCUSSION... 1015 AM CDT MINOR TWEAKS MADE TO GOING FORECAST. THE GENERAL TREND CONTINUES HOWEVER WITH ISOLATED/SCATTERED SHOWERS AND A FEW STORMS AT MOST MOVING EAST...ALONG WITH HIGHS MAINLY IN THE LOWER TO MID 70S...WITH A FEW PLACES IN NORTH CENTRAL IL LIKELY TO TOP OUT ONLY IN THE UPPER 60S. THE MID-LEVEL TROUGH CENTERED ACROSS THE UPPER MIDWEST CONTINUES TO SEE A NARROW DEEP MOIST PLUME AHEAD OF ITS HEIGHT FALLS...AND THAT AXIS IS MOVING ACROSS THE AREA. THIS CORRIDOR BASICALLY DEFINES WHERE SHOWERS ARE POSSIBLE AS THE COLUMN IS SIMPLY TOO DRY ELSEWHERE. THE LEADING EDGE OF SHOWERS AND ISOLATED STORMS HAS WEAKENED SINCE EARLY MORNING WITH A DECAY OF THE LLJ/MOISTURE TRANSPORT. WOULD EXPECT TO STILL SEE A COVERAGE RE-INCREASE IN SHOWERS EAST OF THE I-55 CORRIDOR AS MID-LEVEL JET AND SHEARED SHORT WAVE ACROSS CENTRAL MO PROGRESSES NORTHEAST AND PROVIDES SLIGHTLY MORE FORCING. THE SURFACE FRONT ALREADY IS KNOCKING ON THE DOOR OF THE WESTERN FORECAST AREA AND JUST OVERALL IMPROVED CONVERGENCE COULD HELP AN INCREASE IN SOME SHOWERS THE NEXT FEW HOURS AS WELL. THE 12Z DVN SOUNDING HAD STEEP LAPSE RATES FROM 850-700MB YIELDING TOTAL TOTAL AND K-INDEX VALUES SUPPORTIVE OF ISOLATED THUNDER AND WE DID SEE THAT EARLIER. RAP INDICATIONS ARE FOR THE SAME AMOUNT OF INSTABILITY TO EVOLVE EAST SO WE MAINTAIN THE SLIGHT CHANCE OF THUNDER. TEMPERATURES ARE BATTLING CLOUD COVER IN NORTH CENTRAL IL. WITH FROPA OCCURRING THERE IN THE NEXT FEW HOURS...TEMPERATURES WILL NOT HAVE TOO MUCH LONGER TO RECOVER ESPECIALLY WITH SOME POST-FRONTAL LOW CLOUDS FOR A COUPLE HOURS. SO DID INCH DOWN FORECAST MAXS THERE SOMEWHAT . IT LOOKS LIKE TEMPS MAY DROP A DEGREE OR TWO WITH FROPA OR BASICALLY HOLD STEADY. THE EASTERN FORECAST AREA...ESPECIALLY NORTHWEST IN...WILL CONTINUE TO WARM PRIOR TO THE SCATTERED SHOWER ARRIVAL. MTF && .PREV DISCUSSION... 256 AM CDT TODAY... THIS MORNING...A CLOSED UPPER LOW IN NOTED ON WATER VAPOR IMAGERY LIFTING NORTH INTO MANITOBA...WHILE A COMPACT SHORTWAVE IS ROTATING AROUND THE MAIN LOW...MOVING EAST ACROSS SOUTH DAKOTA. ANOTHER WAVE IS NOTED FARTHER SOUTH...LIFTING NORTHEAST ACROSS FAR EASTERN KANSAS. AT THE SURFACE...DEEP LOW PRESSURE IS ANALYZED OVER SOUTHERN MANITOBA WITH A COLD FRONT EXTENDING SOUTH INTO EASTERN IOWA. A FEW SHOWERS ARE NOTED ALONG THE FRONT...MAINLY AHEAD OF THE SOUTHERN WAVE...OTHERWISE THE FRONT HAS BEEN FAIRLY QUIET OVERNIGHT WITH ONLY A FEW SHOWERS ALONG IT. EXPECT SHOWERS ALONG THE FRONT TO INCREASE IN COVERAGE AROUND DAYBREAK THIS MORNING AS SOUTHERN SHORTWAVE APPROACHES THE AREA...THEN A BRIEF LULL MAY OCCUR ALONG THE FRONT AS THE WAVE DEPARTS MID MORNING. MEANWHILE...NORTHERN STREAM WAVE WILL ARRIVE OVER THE ARE MID AFTERNOON AS THE FRONT IS MOVING ACROSS THE HEART OF THE CWA. GUIDANCE STILL HINTING AT SOME VERY MODEST INSTABILITY...WITH LOW 60 DEWPOINTS POOLING ALONG THE FRONT. WITH THIS IN MIND...STILL CANNOT RULE OUT AN ISOLATED THUNDERSTORM OR TWO...BUT BY AND LARGE THE REGION STILL WILL BE SPLIT BY THE BETTER DYNAMIC FORCING TO THE NORTH AND BETTER INSTABILITY WELL SOUTH. SHOWERS WILL LIKELY BE TIED VERY CLOSELY TO AND SLIGHTLY AHEAD OF THE FRONT...SO THE ENTIRE DAY WILL NOT BE A WASH...WITH ONLY A COUPLE HOUR WINDOW WHERE SHOWERS MAY OCCUR AS THE FRONT SWEEPS OVERHEAD...THEN QUICKLY DRYING OUT BEHIND. TONIGHT THROUGH MONDAY NIGHT... PERIOD WILL BE DOMINATED BY A COOLER AND DRIER AIRMASS...AS HIGH PRESSURE BUILDS OVER THE MID MISSOURI VALLEY TONIGHT WHILE COLD ADVECTION INTO THE AREA ALLOWS H85 TEMPS FALL TO AROUND 4-5C BY DAYBREAK SUNDAY. UNDER CLEAR SKIES AND LIGHT WINDS...AREAS PARTICULARLY WEST OF THE FOX RIVER VALLEY SHOULD QUICKLY DECOUPLE ALLOWING TEMPS TO PLUMMET. BLENDED TOWARDS COOLER GUIDANCE...AND CONTINUE TO EXPECT SOME OF THE TYPICAL COOL SPOTS TO FALL INTO THE 30S...THOUGH THE URBAN HEAT ISLAND OF CHICAGO WILL HELP KEEP TEMPERATURES PROPPED UP AROUND 50 IN THE METRO AREA. FOR SUNDAY...CLIMATOLOGY SHOWS MEAN HIGH TEMPERATURES IN THE LOW TO MID 60S GIVEN THE H85 TEMPS...AND H92 TEMPS AROUND 14C. TEMPERATURES WILL LIKELY BE IN THE LOW 60S NEAR THE LAKE FRONT WHERE ONSHORE WINDS WILL KEEP TEMPERATURES A FEW DEGREES COOLER COMPARED TO INLAND. VERY DRY AIR ALOFT WILL BE MIXED DOWN TO THE SURFACE WITH DEWPOINTS EXPECTED TO FALL INTO THE LOW 30S WEST TO UPPER 30S EAST RESULTING IN RELATIVE HUMIDITY FALLING TO INTO THE 25 TO 35 PERCENT RANGE. CONDITIONS SHOULD BE MOSTLY UNCHANGED HEADING INTO SUNDAY NIGHT AS HIGH PRESSURE SHIFTS ENE OVER WISCONSIN. ONCE AGAIN... EXPECT TEMPERATURES TO RADIATE EFFICIENTLY...AND LEANED TOWARDS COOLER SIDE OF GUIDANCE. TEMPERATURES WILL REBOUND SOME MONDAY AS THE HIGH CONTINUES TO SHIFT EAST OVER NORTHERN MICHIGAN WITH RETURN FLOW AND WARM ADVECTION OVER SPREADING THE AREA. ALSO SHOULD SEE AN INCREASE IN HIGH AND MID LEVEL CLOUD COVER AS LOW PRESSURE MOVES EAST FROM THE COLORADO FRONT RANGE TO THE MID MISSOURI VALLEY. TUESDAY THROUGH FRIDAY... STRONG WAVE MOVING ONTO THE PACIFIC NORTHWEST COAST THIS MORNING WILL CARVE OUT A BROAD TROUGH OVER THE WESTERN CONUS BY TUESDAY WITH A CLOSED UPPER LOW FORMING OVER THE GREAT BASIN. THIS UPPER LOW WILL MOVE EAST INTO THE UPPER MIDWEST TUESDAY...WITH THE AFOREMENTIONED SURFACE LOW MOVING OVER WI/MN. WHILE THERE ARE STILL TIMING/TRACK DIFFERENCES THIS FAR OUT...OVERALL EVOLUTION OF THE SYSTEM IS FAIRLY SIMILAR BETWEEN MODELS. WARM ADVECTION/ISENTROPIC ASCENT WILL LEAD TO SHOWERS AHEAD OF THE LOW TUESDAY...WITH SHOWERS ALONG THE TRAILING COLD FRONT TUESDAY NIGHT. DEPENDING ON THE TRACK OF THE LOW...DRY SLOT WILL LEAD TO A LULL IN PRECIP BEFORE WRAP AROUND MOISTURE BEHIND THE LOW OVERSPREADS THE AREA ONCE AGAIN WEDNESDAY. PERIOD OF BELOW NORMAL TEMPS IS EXPECTED BEHIND THE SURFACE LOW TO END THE WORK WEEK AS THE OVERALL PATTERN REMAINS AMPLIFIED WITH A BROAD TROUGH SPANNING THE EASTERN CONUS. INTERESTINGLY..TAKING A PEAK INTO NEXT WEEKEND...BOTH THE 00Z ECMWF AND GFS SHOW A VERY COLD AIRMASS SETTLING OVER ONTARIO //H85 TEMPS DROPPING TO -10 TO -12C// WITH MODELS HINTING TO SOME DEGREE THAT THIS COLD AIR WILL MAKE A PUSH INTO THE GREAT LAKES REGION WITH SUB ZERO H85 TEMPS LOCALLY...WHICH IF IT PANS OUT WOULD MAY LEAD TO WELL BELOW NORMAL TEMPS WITH HIGHS POSSIBLY TOPPING OUT IN THE 40S. DEUBELBEISS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 14Z... * SCATTERED SHOWERS LATE THIS MORNING THROUGH MID AFTERNOON WITH A CHANCE FOR ISOLATED THUNDER BETWEEN 18Z-20Z. * A POSSIBLE 2-3 HOUR PERIOD OF MVFR CIGS ALONG THE COLD FRONT LATER THIS AFTERNOON...MAINLY BETWEEN 21Z AND 00Z. * WIND SHIFT FROM SOUTH TO WEST-SOUTHWEST LATE THIS AFTERNOON WITH COLD FRONTAL PASSAGE. A SHIFT TO NORTHERLY IS EXPECTED SUNDAY MORNING. MDB/MTF //DISCUSSION...UPDATED 12Z... STRONG LOW PRESSURE IS MOVING NORTH-NORTHEAST ACROSS FAR SOUTHEAST MANITOBA HAS A COLD FRONTAL BOUNDARY STRETCHING SOUTHWARD FROM IT WHICH IS JUST NOW REACHING THE MISSISSIPPI RIVER NEAR THE QUAD CITIES. SEVERAL WEAK WAVES APPEAR TO BE EMBEDDED IN THE UPPER FLOW PATTERN. A NARROW BAND OF SHOWERS HAS DEVELOPED OUT AHEAD OF THE FRONT IN CONJUNCTION WITH THE ACTIVE UPPER FLOW. THE EASTWARD PUSH OF THIS BAND HAS BEEN SLOW BUT IT LOOKS TO CONTINUE THROUGH THE MORNING. THE FRONT WILL TRY TO CATCH UP TO THE UPPER FORCING THROUGH THE DAY SO ANY GAP BETWEEN THE CURRENT ACTIVITY NEAR RFD AND ACTIVITY NEAR THE FRONT TO THE WEST MAY CLOSE WITH TIME. WILL CONTINUE WITH A FEW HOURS OF TEMPO SHOWERS ACROSS THE TERMINALS INTO THE AFTERNOON. STILL CANNOT RULE OUT THUNDER BUT THUNDER COVERAGE LOOKS TO BE ISOLATED OVER THE AREA WITH THE THREAT TOO LOW TO MENTION IN THE TAFS AT THIS TIME. BRIEF MVFR CIGS MAY ACCOMPANY THE FRONTAL PASSAGE BUT THESE LOOKS TO BE SHORT LIVED SO WILL CARRY PREVAILING LOWER END VFR CLOUD COVER. SOUTH-SOUTHEAST WINDS WILL INCREASE IN SPEED WITH TIME THIS MORNING AND TURN MORE SOUTH OR EVEN SOUTH-SOUTHWEST BEFORE TURNING SOUTHWEST THEN WEST WITH THE APPROACH AND PASSAGE OF THE FRONT THROUGH THE AFTERNOON. SPEEDS WILL EASE UP OVERNIGHT AS HIGH PRESSURE ARRIVES KEEPING QUIET WEATHER IN PLACE. WINDS WILL THEN TURN MORE NORTHERLY SUNDAY MORNING. MDB //ORD AND MDW CONFIDENCE...UPDATED 14Z... * HIGH CONFIDENCE IN SCATTERED SHOWERS IN THE AREA FROM 17Z-20Z. LOW CONFIDENCE IF THUNDER WILL OCCUR AT THE AIRPORT ITSELF. * LOW CONFIDENCE IF MVFR CIGS WILL MATERIALIZE LATER THIS AFTERNOON. * HIGH CONFIDENCE IN WIND TRENDS. MDB/MTF //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT AND MONDAY...VFR. TUESDAY...CHANCE SHRA/TSRA. NON-VFR POSSIBLE. WEDNESDAY AND THURSDAY...SLIGHT CHANCE -SHRA...MAINLY VFR. FRIDAY...VFR. && .MARINE... 125 AM CDT DEEP LOW PRESSURE SYSTEM OF 991 MB WAS OVER FAR NORTHEASTERN NORTH DAKOTA EARLY THIS MORNING...AND WILL CONTINUE TO LIFT NORTH ACROSS FAR EASTERN MANITOBA AND SLOWLY FILL THROUGH THIS EVENING. SURFACE PRESSURE FALLS ASSOCIATED WITH THIS FEATURE ACROSS ONTARIO AND THE NORTHERN GREAT LAKES WILL RESULT IN SOUTH WINDS PICKING UP INTO THE 20-25 KT RANGE ESPECIALLY ACROSS NORTHERN LAKE MICHIGAN TODAY...WITH 30 KTS NOT TOO FAR ABOVE THE THERMALLY STABLE MARINE LAYER. THE COLD FRONT TRAILING FROM THE LOW WILL MOVE EAST ACROSS THE LAKE THIS AFTERNOON...SHIFTING WINDS INITIALLY TO THE WEST-SOUTHWEST AND EVENTUALLY MORE NORTHWEST TONIGHT. FORECAST SOUNDINGS FROM SEVERAL MODELS INDICATE THAT THE MIXED LAYER WILL DEEPEN BEHIND THE FRONT BY THIS EVENING AS COOL ADVECTION STEEPENS LAPSE RATES OVER THE WATER...WHICH MAY THEN ALLOW FOR 30 KT GUSTS THIS EVENING ESPECIALLY NORTH AS THE LOW CONTINUES TO PULL AWAY. HIGH PRESSURE THEN BUILDS QUICKLY INTO THE REGION SUNDAY...ALLOWING A QUICK DECREASE IN WINDS AS THE RIDGE APPROACHES. THE SURFACE RIDGE WILL MOVE EAST OF LAKE MICHIGAN SUNDAY NIGHT...WITH A NEW AREA OF LOW PRESSURE EXPECTED TO DEVELOP ACROSS THE CENTRAL HIGH PLAINS BY MONDAY MORNING. WHILE SOME DETAILS DIFFER BETWEEN MODEL RUNS...THIS LOW IS BASICALLY FORECAST TO MOVE NORTHEAST ACROSS IOWA/MINNESOTA MONDAY NIGHT AND TUESDAY BEFORE CROSSING CENTRAL OR NORTHERN LAKE MICHIGAN TUESDAY NIGHT INTO WEDNESDAY. THIS WILL LIKELY RESULT IN EAST-SOUTHEAST WINDS DEVELOPING AHEAD OF THE LOW AND INCREASING ESPECIALLY MONDAY NIGHT WITH GUSTS POTENTIALLY IN THE 20-25 KT RANGE. THE GRADIENT WILL THEN WEAKEN BY LATE TUESDAY AS THE LOW CROSSES THE LAKE. DETAILS IN FORECAST WIND SPEED AND DIRECTION WILL HAVE TO BE FINE TUNED AS THE TRACK OF THE SURFACE LOW BECOMES MORE CERTAIN. RATZER && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
605 PM EDT SAT OCT 12 2013 .SYNOPSIS... ISSUED AT 604 PM EDT SAT OCT 12 2013 A WEAKENING COLD FRONT WILL MOVE EAST ACROSS THE AREA TONIGHT...BRINGING A CHANCE FOR SCATTERED SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM. MANY LOCATIONS MAY REMAIN DRY THOUGH. HIGH PRESSURE WILL BUILD IN FOR SUNDAY AND MONDAY WITH COOLER TEMPERATURES AND DRY WEATHER. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 350 PM EDT SAT OCT 12 2013 LEAD UPPER LEVEL SHORT WAVE ENTERING NORTHWEST ILLINOIS THIS AFTERNOON WILL CONTINUE TO LIFT NORTHEAST THROUGH THE WESTERN GREAT LAKES REGION THIS EVENING. SOUTHERN FRINGE OF DPVA ZONE WITH THIS VORT MAX AND PROXIMITY TO RIGHT ENTRANCE REGION OF WESTERN GREAT LAKES UPPER JET STREAK SHOULD SUPPORT SCT SHOWER DEVELOPMENT INTO NORTHWEST INDIANA/SOUTHWEST LOWER MICHIGAN OVER THE NEXT SEVERAL HOURS. A PREFRONTAL BAND OF SHOWERS LIKELY ASSOCIATED WITH NARROW ZONE OF STRONG LOW LEVEL THETAE ADVECTION HAS BEEN DIMINISHING IN COVERAGE THROUGH THE AFTERNOON...BUT COULD BE ENOUGH FORCING FOR ISOLATED/SCATTERED SHOWERS OVER NEXT FEW HOURS ACROSS EXTREME NORTHWEST PORTIONS OF THE AREA. SHEARING NATURE TO NORTHERN ILLINOIS SHORT WAVE AS IT LIFTS NORTHEAST SHOULD LEAD TO EVENTUAL WEAKENING OF LOW LEVEL FRONTOGENESIS FORCING FROM WEST TO EAST ACROSS THE AREA OVERNIGHT AS COLD FRONT MOVES THROUGH. ALONG WITH THIS WEAKENING CONVERGENCE...SHORT TERM MODEL GUIDANCE IS IN GOOD AGREEMENT IN PWATS DIMINISHING INTO THE 1.25 RANGE AS THIS MOISTURE AXIS SHIFTS INTO FAR EASTERN PORTIONS OF THE FORECAST AREA OVERNIGHT. BASED ON RECENT TRENDS AND STRONGEST MID/UPPER FORCING SHIFTING NORTH OF THE AREA...GREATEST PRECIP COVERAGE SHOULD REMAIN TO THE NORTH AND HAVE LOWERED POPS INTO THE LOW TO MID CHANCE RANGE...AND THIS TREND MAY NEED TO BE CONTINUED THIS EVENING. HAVE MADE NO CHANGE TO PREVIOUS FORECAST IN REGARDS TO DIMINISHING POPS FROM WEST TO EAST TONIGHT WITH CONTINUED WEAKENING OF LOW/MID LEVEL FRONTOGENESIS FORCING AND WANING MID/UPPER LEVEL FORCING. 18Z RUC ANALYSIS DEPICTS AXIS OF 250-500 J/KG MUCAPES TRACKING INTO NORTHWEST INDIANA THIS AFTERNOON IN ASSOCIATION WITH THIS LOW LEVEL MOISTURE AXIS...WHICH COMBINED WITH SOUTHERN TAIL OF STRONGER UPPER FORCING COULD BE ENOUGH FOR AN ISOLD TSRA ACROSS ESPECIALLY THE WESTERN HALF OF THE AREA THIS EVENING. DID MAINTAIN SOME SLIGHT CHANCE -RW POPS ACROSS THE FAR SOUTHEAST INTO SUNDAY MORNING WITH SOME SIGNAL IN MODEL GUIDANCE OF LINGERING WEAK MID LEVEL FRONTOGENESIS POSSIBLY SUSTAINING A FEW LIGHT RAIN SHOWERS. STRONG LOW LEVEL CAA TO OVERSPREAD THE AREA LATE TONIGHT INTO SUNDAY MORNING WITH COOLER CONDITIONS FROM THE MID 60S NORTHWEST TO AROUND 70 SOUTHEAST SUNDAY AFTERNOON. && .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 350 PM EDT SAT OCT 12 2013 HIGH PRESSURE WILL KEEP THE AREA HIGH AND DRY AS YET ANOTHER WAVE ROUNDS THE WEST COAST TROUGH AND TAKES AIM ON THE REGION. MODELS CONTINUE TO VARY ON TIMING/SPEED OF EJECTION OF THIS FEATURE WITH 12Z GEM SLOWER VS 12Z GFS. ECMWF IS FLIP-FLOPPING SOLUTIONS WITH NEW 12Z RUN VERY SIMILAR IN SPEED/LOCATION TO 12Z GFS. CONFIDENCE HIGH ENOUGH IN SLOWING DOWN ARRIVAL ON TUESDAY TO BACK OFF POPS IN THE EAST...BUT TO INCREASE TO LOW END LIKELY TUESDAY NIGHT WHICH HAS BEEN CONSISTENTLY THE MOST FAVORED PERIOD. BEYOND THIS...TIMING ISSUES ALREADY NOTED WITH TROUGH WARRANTS HOLDING ONTO SLGT CHC/CHC POPS WEDS/WEDS WITH HIGHEST EAST WHERE FRONTAL BOUNDARY MAY LINGER LONGER. COLDER AIR ARRIVES BEHIND THE SYSTEM WITH MODELS AGREEING TO SOME EXTENT ON 850 MB TEMPS DROPPING TO AROUND 0 C. AS A RESULT...BELOW NORMAL TEMPS IN THE 50S WILL SETTLE IN AND PERSIST THROUGH SATURDAY. LAKE ENHANCED SHOWERS WILL BE POSSIBLE AT TIMES THURS INTO FRI AS WEAK WAVES ROTATE THROUGH TO CONTRIBUTE MSTR...LIFT AND SOMEWHAT MORE FAVORABLE INVERSION HGTS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 350 PM EDT SAT OCT 12 2013 A STRONG UPPER VORT MAX ACROSS NORTHERN IOWA/MINNESOTA WILL CONTINUE TO TRACK INTO THE WESTERN GREAT LAKES THIS EVENING. THE APPROACH OF THIS SHORT WAVE HAS LED TO AN INCREASE IN THE COVERAGE OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS NORTH CENTRAL ILLINOIS. ANOTHER AREA OF PREFRONTAL SHOWERS CONTINUES TO LIFT NORTHEAST ACROSS EAST CENTRAL ILLINOIS. CONFIDENCE IS SOMEWHAT LOW IN REGARDS TO PRECIP COVERAGE FOR TERMINALS GIVEN AFOREMENTIONED IOWA VORT MAX WILL BE LIFTING NORTHEAST THIS AFTERNOON WITH WEAKENING CONVERGENCE ALONG THE COLD FRONT THIS EVENING. WILL CARRY TEMPO -SHRA IN THE 22Z-02Z TIMEFRAME WITH MVFR CIGS POSSIBLE IN ASSOCIATION WITH POOLED MOISTURE ALONG THE FRONT. WEAKENING FRONTAL CONVERGENCE WITH EASTWARD EXTENT LENDS EVEN LOWER CONFIDENCE TO SHRA COVERAGE AT KFWA WHERE HAVE LIMITED MENTION TO VCSH TONIGHT. AN ISOLATED TSRA IS POSSIBLE AT KSBN...ALTHOUGH WITH EARLY EVENING FRONTAL TIMING AND LOSS OF PEAK INSTABILITY WILL CONTINUE TO OMIT WITH 18Z TAFS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...CEO SHORT TERM...MARSILI LONG TERM...FISHER AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
356 PM EDT SAT OCT 12 2013 .SYNOPSIS... ISSUED AT 1213 PM EDT SAT OCT 12 2013 AN UPPER LEVEL DISTURBANCE TRACKING ACROSS THE WESTERN GREAT LAKES REGION TONIGHT WILL ALLOW A COLD FRONT TO TRACK FROM WEST TO EAST ACROSS THE AREA. SCATTERED SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORMS WILL ACCOMPANY THE COLD FRONT TONIGHT. A RETURN TO SOMEWHAT COOLER CONDITIONS IS THEN EXPECTED FOR THE EARLY PORTIONS OF NEXT WEEK. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 350 PM EDT SAT OCT 12 2013 LEAD UPPER LEVEL SHORT WAVE ENTERING NORTHWEST ILLINOIS THIS AFTERNOON WILL CONTINUE TO LIFT NORTHEAST THROUGH THE WESTERN GREAT LAKES REGION THIS EVENING. SOUTHERN FRINGE OF DPVA ZONE WITH THIS VORT MAX AND PROXIMITY TO RIGHT ENTRANCE REGION OF WESTERN GREAT LAKES UPPER JET STREAK SHOULD SUPPORT SCT SHOWER DEVELOPMENT INTO NORTHWEST INDIANA/SOUTHWEST LOWER MICHIGAN OVER THE NEXT SEVERAL HOURS. A PREFRONTAL BAND OF SHOWERS LIKELY ASSOCIATED WITH NARROW ZONE OF STRONG LOW LEVEL THETAE ADVECTION HAS BEEN DIMINISHING IN COVERAGE THROUGH THE AFTERNOON...BUT COULD BE ENOUGH FORCING FOR ISOLATED/SCATTERED SHOWERS OVER NEXT FEW HOURS ACROSS EXTREME NORTHWEST PORTIONS OF THE AREA. SHEARING NATURE TO NORTHERN ILLINOIS SHORT WAVE AS IT LIFTS NORTHEAST SHOULD LEAD TO EVENTUAL WEAKENING OF LOW LEVEL FRONTOGENESIS FORCING FROM WEST TO EAST ACROSS THE AREA OVERNIGHT AS COLD FRONT MOVES THROUGH. ALONG WITH THIS WEAKENING CONVERGENCE...SHORT TERM MODEL GUIDANCE IS IN GOOD AGREEMENT IN PWATS DIMINISHING INTO THE 1.25 RANGE AS THIS MOISTURE AXIS SHIFTS INTO FAR EASTERN PORTIONS OF THE FORECAST AREA OVERNIGHT. BASED ON RECENT TRENDS AND STRONGEST MID/UPPER FORCING SHIFTING NORTH OF THE AREA...GREATEST PRECIP COVERAGE SHOULD REMAIN TO THE NORTH AND HAVE LOWERED POPS INTO THE LOW TO MID CHANCE RANGE...AND THIS TREND MAY NEED TO BE CONTINUED THIS EVENING. HAVE MADE NO CHANGE TO PREVIOUS FORECAST IN REGARDS TO DIMINISHING POPS FROM WEST TO EAST TONIGHT WITH CONTINUED WEAKENING OF LOW/MID LEVEL FRONTOGENESIS FORCING AND WANING MID/UPPER LEVEL FORCING. 18Z RUC ANALYSIS DEPICTS AXIS OF 250-500 J/KG MUCAPES TRACKING INTO NORTHWEST INDIANA THIS AFTERNOON IN ASSOCIATION WITH THIS LOW LEVEL MOISTURE AXIS...WHICH COMBINED WITH SOUTHERN TAIL OF STRONGER UPPER FORCING COULD BE ENOUGH FOR AN ISOLD TSRA ACROSS ESPECIALLY THE WESTERN HALF OF THE AREA THIS EVENING. DID MAINTAIN SOME SLIGHT CHANCE -RW POPS ACROSS THE FAR SOUTHEAST INTO SUNDAY MORNING WITH SOME SIGNAL IN MODEL GUIDANCE OF LINGERING WEAK MID LEVEL FRONTOGENESIS POSSIBLY SUSTAINING A FEW LIGHT RAIN SHOWERS. STRONG LOW LEVEL CAA TO OVERSPREAD THE AREA LATE TONIGHT INTO SUNDAY MORNING WITH COOLER CONDITIONS FROM THE MID 60S NORTHWEST TO AROUND 70 SOUTHEAST SUNDAY AFTERNOON. && .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 350 PM EDT SAT OCT 12 2013 HIGH PRESSURE WILL KEEP THE AREA HIGH AND DRY AS YET ANOTHER WAVE ROUNDS THE WEST COAST TROUGH AND TAKES AIM ON THE REGION. MODELS CONTINUE TO VARY ON TIMING/SPEED OF EJECTION OF THIS FEATURE WITH 12Z GEM SLOWER VS 12Z GFS. ECMWF IS FLIP-FLOPPING SOLUTIONS WITH NEW 12Z RUN VERY SIMILAR IN SPEED/LOCATION TO 12Z GFS. CONFIDENCE HIGH ENOUGH IN SLOWING DOWN ARRIVAL ON TUESDAY TO BACK OFF POPS IN THE EAST...BUT TO INCREASE TO LOW END LIKELY TUESDAY NIGHT WHICH HAS BEEN CONSISTENTLY THE MOST FAVORED PERIOD. BEYOND THIS...TIMING ISSUES ALREADY NOTED WITH TROUGH WARRANTS HOLDING ONTO SLGT CHC/CHC POPS WEDS/WEDS WITH HIGHEST EAST WHERE FRONTAL BOUNDARY MAY LINGER LONGER. COLDER AIR ARRIVES BEHIND THE SYSTEM WITH MODELS AGREEING TO SOME EXTENT ON 850 MB TEMPS DROPPING TO AROUND 0 C. AS A RESULT...BELOW NORMAL TEMPS IN THE 50S WILL SETTLE IN AND PERSIST THROUGH SATURDAY. LAKE ENHANCED SHOWERS WILL BE POSSIBLE AT TIMES THURS INTO FRI AS WEAK WAVES ROTATE THROUGH TO CONTRIBUTE MSTR...LIFT AND SOMEWHAT MORE FAVORABLE INVERSION HGTS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 350 PM EDT SAT OCT 12 2013 A STRONG UPPER VORT MAX ACROSS NORTHERN IOWA/MINNESOTA WILL CONTINUE TO TRACK INTO THE WESTERN GREAT LAKES THIS EVENING. THE APPROACH OF THIS SHORT WAVE HAS LED TO AN INCREASE IN THE COVERAGE OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS NORTH CENTRAL ILLINOIS. ANOTHER AREA OF PREFRONTAL SHOWERS CONTINUES TO LIFT NORTHEAST ACROSS EAST CENTRAL ILLINOIS. CONFIDENCE IS SOMEWHAT LOW IN REGARDS TO PRECIP COVERAGE FOR TERMINALS GIVEN AFOREMENTIONED IOWA VORT MAX WILL BE LIFTING NORTHEAST THIS AFTERNOON WITH WEAKENING CONVERGENCE ALONG THE COLD FRONT THIS EVENING. WILL CARRY TEMPO -SHRA IN THE 22Z-02Z TIMEFRAME WITH MVFR CIGS POSSIBLE IN ASSOCIATION WITH POOLED MOISTURE ALONG THE FRONT. WEAKENING FRONTAL CONVERGENCE WITH EASTWARD EXTENT LENDS EVEN LOWER CONFIDENCE TO SHRA COVERAGE AT KFWA WHERE HAVE LIMITED MENTION TO VCSH TONIGHT. AN ISOLATED TSRA IS POSSIBLE AT KSBN...ALTHOUGH WITH EARLY EVENING FRONTAL TIMING AND LOSS OF PEAK INSTABILITY WILL CONTINUE TO OMIT WITH 18Z TAFS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SYNOPSIS...MARSILI SHORT TERM...MARSILI LONG TERM...FISHER AVIATION...MARSILI VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV WWW.TWITTER.COM/NWSIWX WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
234 PM EDT SAT OCT 12 2013 .UPDATE... ISSUED AT 230 PM EDT SAT OCT 12 2013 HOURLY GRIDS WERE UPDATED BASED ON RECENT SATELLITE AND OBSERVATION TRENDS. THE STRATUS AND STRATOCU OVER THE EASTERN CWA HAS GRADUALLY BEEN ERODING WITH CU DEVELOPING TO ITS WEST. THIS TREND SHOULD CONTINUE OVER THE NEXT FEW HOURS WITH CU AND STRATOCU TENDING TO DISSIPATE DURING THE EVENING. UPDATE ISSUED AT 1122 AM EDT SAT OCT 12 2013 STRATUS AROUND THE WESTERN EDGE OF THE EAST COAST CLOSED LOW HAS ADVECTED ABOUT A THIRD TO A HALF OF THE WAY WEST ACROSS THE CWA THIS MORNING. THE WESTERN EDGE OF THIS IS NEAR THE KY HIGHWAY 15 CORRIDOR IN EASTERN KY. DAYTIME HEATING MAY TEND TO WHITTLE AWAY AT THE WESTERN TO SOUTHWESTERN EDGE OF THIS...BUT SUFFICIENT MOISTURE IS ALSO IN PLACE FOR SOME PANCAKE CU TO THE WEST OF THIS. THE STRATUS SHOULD BECOME MORE STRATOCU AND CU IN NATURE AS THE AFTERNOON PROGRESSES AND MIX OUT TO AN EXTENT. THE TUG VALLEY NEAR THE WV BORDER APPEARS TO BE DESTINED TO BE CLOUDY THE LONGEST. THE CLOUD COVER WILL AFFECT DAYTIME HIGHS AND THEY HAVE BEEN ADJUSTED DOWNWARD ACCORDINGLY A FEW DEGREES IN THE EASTERN HALF OF THE CWA...ESPECIALLY NEAR THE WV BORDER. UPDATE ISSUED AT 758 AM EDT SAT OCT 12 2013 LOW CLOUDS HAVE MADE THEIR WAY INTO THE FORECAST AREA FROM THE EAST. THE RUC BRINGS THEM A BIT FURTHER WEST THIS MORNING BEFORE THEY BEGIN TO BREAK UP FOR THE AFTERNOON...AND THIS HAS BEEN DEPICTED IN THE UPDATED FORECAST GRIDS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 400 AM EDT SAT OCT 12 2013 A DYING AREA OF LOW PRESSURE WHICH HAS BEEN SITUATED TO OUR EAST FOR DAYS IS PROVIDING A MEAGER AMOUNT OF LOW-MID LEVEL MOISTURE TO OUR EASTERN COUNTIES. THIS LED TO PERIODS OF LOW CLOUDS DURING THE NIGHT. WITH DAYTIME HEATING...IT MAY ALSO BE ENOUGH FOR A FEW LIGHT SHOWERS TO DEVELOP THIS AFTERNOON...AND WILL USE A 20 PERCENT POP OVER THE EASTERN TIP OF THE STATE. WILL LOOK FOR ANY PRECIP TO END AS TEMPS COOL DOWN AGAIN TONIGHT. A DYING COLD FRONT WILL PUSH IN FROM THE WEST ON SUNDAY...AND WITH RESIDUAL LOW-MID LEVEL MOISTURE FROM THE LOW...THERE WILL BE A POSSIBILITY OF SHOWERS. WILL NOT INCLUDE ANY THUNDER THIS WEEKEND...SINCE THE CONVECTION LOOKS LIKE IT WILL BE CAPPED BELOW THE -20C LEVEL. WE WILL SEE VALLEY FOG IN SOME LOCATIONS THIS MORNING AND AGAIN TONIGHT INTO SUNDAY MORNING. IT WILL BE LIMITED IN EASTERN AREAS WHERE CLOUDS ARE MORE SIGNIFICANT. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 413 AM EDT SAT OCT 12 2013 BY 0Z MONDAY...UPPER LEVEL PATTERN WILL START OFF IN A GOOD AGREEMENT...WITH AN UPPER LEVEL RIDGE AXIS EXITING EAST OF THE APPALACHIANS...A WEAK CLOSED LOW OFF THE NORTH CAROLINA COAST...AND A STRONGER CLOSED LOW ENTERING THE HUDSON BAY IN CENTRAL CANADA. THE LOW IN CANADA WILL BE THE MAIN CONCERN DURING THE MID-TERM...AS IT WILL ESTABLISH A STRONG SURFACE LOW AND AN ASSOCIATED COLD FRONT WHICH IS POISED TO MOVE THROUGH WESTERN AND CENTRAL KY DURING THE DAY SUNDAY /DURING THE SHORT TERM PERIOD/. BY THE START OF THE EXTENDED FORECAST...THIS FRONT WILL BE MOVING THROUGH AND EXITING EASTERN KY. LATEST MODEL RUNS ARE STILL SUPPORTING THE IDEA OF LIGHT RAIN SHOWERS CONTINUING SUNDAY EVENING INTO SUNDAY NIGHT...BUT ALL RUNS ARE NOW IN AGREEMENT THAT SOME OF THESE ISOLATED SHOWERS COULD LINGER ACROSS ERN KY INTO MONDAY AS WELL. ADDED IN SOME MARGINAL SLIGHT CHANCE POPS MONDAY TO ACCOUNT FOR THIS. SHORT TERM RIDGING WILL TAKE HOLD BY MONDAY NIGHT AS ANOTHER STRONG 500MB CLOSED LOW BEGINS MOVING INTO THE NORTHERN PLAINS. AT THE SURFACE...ANOTHER COLD FRONT WILL PROTRUDE AHEAD OF THE SURFACE LOW...THIS ONE STRONGER AND PULLING IN DEEP WARM MOISTURE FROM THE GULF AS IT NEARS THE MISSISSIPPI RIVER VALLEY. MODELS ARE STILL IN SOMEWHAT OF A POOR AGREEMENT BY THIS POINT...WITH LITTLE CERTAINTY AS TO WHEN THE PRECIP WILL REACH THE ERN KY REGION. WILL CONTINUE WITH MODEL CONSENSUS FOR THIS EVENT...BUT DO EXPECT SOME PRECIP TO BEGIN MOVING IN BY TUESDAY EVENING. THE FRONT WILL SLOW AS IT REACHES KY...ALLOWING MOISTURE TO SLOWLY INCREASE AND CONTINUE THROUGH THURSDAY NIGHT. HIGH PRESSURE WILL SET IN FOR A VERY SHORT TIME PERIOD ON FRIDAY. HOWEVER...A SECONDARY FRONT WILL BEGIN PUSHING INTO THE REGION BY FRIDAY AFTERNOON. WITH LINGERING LOW LEVEL MOISTURE FROM THE PREVIOUS SYSTEM...ALONG WITH ISENTROPIC LIFT AS THE FRONT PASSES...EXPECT MORE SHOWERS TO DEVELOP BY SATURDAY AFTERNOON ACCORDING TO THE LATEST ECMWF. TEMPERATURES WILL FINALLY DROP DOWN TO MORE SEASONABLE /IF NOT SLIGHTLY BELOW/ AFTER THE PASSAGE OF THE COLD FRONT ON THURSDAY...AND REMAIN SO THROUGH THE REMAINDER OF THE FORECAST PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 225 PM EDT SAT OCT 12 2013 THE STRATUS AND STRATOCU EAST AND SOUTHEAST OF JKL CONTINUES TO LIFT AND MIXOUT THOUGH IFR IS POSSIBLE AT SJS FOR THE NEXT COUPLE OF HOURS. OTHERWISE...CU IN THE VFR RANGE SHOULD DEVELOP FURTHER WEST NEAR JKL...LOZ AND SME WITH THIS TENDING TO DISSIPATE AFTER 21Z. SOME CLOUDS MAY LINGER IN THE LOWER END OF THE VFR RANGE OVERNIGHT...ESPECIALLY FROM JKL SOUTHEAST AND EAST. HOWEVER...VALLEY FOG SHOULD DEVELOP AGAIN AROUND 6Z...BUT WILL LIKELY BE TEMPERED BY CLOUDS IN THE EASTERN PART OF THE AREA. THIS COULD SET THE STAGE FOR FOG WITH VIS DOWN TO AIRPORT MINS OR BELOW BETWEEN 8Z AND 13Z AT LOZ AND SME AND OTHER LOCATIONS IN THE SOUTHWEST CWA. OTHERWISE...SOME CU NEAR 5KFT AND SOME ISOLATED SHOWERS MAY DEVELOP LATE IN THE PERIOD AS A COLD FRONT AND UPPER LEVEL DISTURBANCE APPROACH. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...HAL LONG TERM...JMW AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1134 AM EDT SAT OCT 12 2013 .UPDATE... ISSUED AT 1122 AM EDT SAT OCT 12 2013 STRATUS AROUND THE WESTERN EDGE OF THE EAST COAST CLOSED LOW HAS ADVECTED ABOUT A THIRD TO A HALF OF THE WAY WEST ACROSS THE CWA THIS MORNING. THE WESTERN EDGE OF THIS IS NEAR THE KY HIGHWAY 15 CORRIDOR IN EASTERN KY. DAYTIME HEATING MAY TEND TO WHITTLE AWAY AT THE WESTERN TO SOUTHWESTERN EDGE OF THIS...BUT SUFFICIENT MOISTURE IS ALSO IN PLACE FOR SOME PANCAKE CU TO THE WEST OF THIS. THE STRATUS SHOULD BECOME MORE STRATOCU AND CU IN NATURE AS THE AFTERNOON PROGRESSES AND MIX OUT TO AN EXTENT. THE TUG VALLEY NEAR THE WV BORDER APPEARS TO BE DESTINED TO BE CLOUDY THE LONGEST. THE CLOUD COVER WILL AFFECT DAYTIME HIGHS AND THEY HAVE BEEN ADJUSTED DOWNWARD ACCORDINGLY A FEW DEGREES IN THE EASTERN HALF OF THE CWA...ESPECIALLY NEAR THE WV BORDER. UPDATE ISSUED AT 758 AM EDT SAT OCT 12 2013 LOW CLOUDS HAVE MADE THEIR WAY INTO THE FORECAST AREA FROM THE EAST. THE RUC BRINGS THEM A BIT FURTHER WEST THIS MORNING BEFORE THEY BEGIN TO BREAK UP FOR THE AFTERNOON...AND THIS HAS BEEN DEPICTED IN THE UPDATED FORECAST GRIDS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 400 AM EDT SAT OCT 12 2013 A DYING AREA OF LOW PRESSURE WHICH HAS BEEN SITUATED TO OUR EAST FOR DAYS IS PROVIDING A MEAGER AMOUNT OF LOW-MID LEVEL MOISTURE TO OUR EASTERN COUNTIES. THIS LED TO PERIODS OF LOW CLOUDS DURING THE NIGHT. WITH DAYTIME HEATING...IT MAY ALSO BE ENOUGH FOR A FEW LIGHT SHOWERS TO DEVELOP THIS AFTERNOON...AND WILL USE A 20 PERCENT POP OVER THE EASTERN TIP OF THE STATE. WILL LOOK FOR ANY PRECIP TO END AS TEMPS COOL DOWN AGAIN TONIGHT. A DYING COLD FRONT WILL PUSH IN FROM THE WEST ON SUNDAY...AND WITH RESIDUAL LOW-MID LEVEL MOISTURE FROM THE LOW...THERE WILL BE A POSSIBILITY OF SHOWERS. WILL NOT INCLUDE ANY THUNDER THIS WEEKEND...SINCE THE CONVECTION LOOKS LIKE IT WILL BE CAPPED BELOW THE -20C LEVEL. WE WILL SEE VALLEY FOG IN SOME LOCATIONS THIS MORNING AND AGAIN TONIGHT INTO SUNDAY MORNING. IT WILL BE LIMITED IN EASTERN AREAS WHERE CLOUDS ARE MORE SIGNIFICANT. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 413 AM EDT SAT OCT 12 2013 BY 0Z MONDAY...UPPER LEVEL PATTERN WILL START OFF IN A GOOD AGREEMENT...WITH AN UPPER LEVEL RIDGE AXIS EXITING EAST OF THE APPALACHIANS...A WEAK CLOSED LOW OFF THE NORTH CAROLINA COAST...AND A STRONGER CLOSED LOW ENTERING THE HUDSON BAY IN CENTRAL CANADA. THE LOW IN CANADA WILL BE THE MAIN CONCERN DURING THE MID-TERM...AS IT WILL ESTABLISH A STRONG SURFACE LOW AND AN ASSOCIATED COLD FRONT WHICH IS POISED TO MOVE THROUGH WESTERN AND CENTRAL KY DURING THE DAY SUNDAY /DURING THE SHORT TERM PERIOD/. BY THE START OF THE EXTENDED FORECAST...THIS FRONT WILL BE MOVING THROUGH AND EXITING EASTERN KY. LATEST MODEL RUNS ARE STILL SUPPORTING THE IDEA OF LIGHT RAIN SHOWERS CONTINUING SUNDAY EVENING INTO SUNDAY NIGHT...BUT ALL RUNS ARE NOW IN AGREEMENT THAT SOME OF THESE ISOLATED SHOWERS COULD LINGER ACROSS ERN KY INTO MONDAY AS WELL. ADDED IN SOME MARGINAL SLIGHT CHANCE POPS MONDAY TO ACCOUNT FOR THIS. SHORT TERM RIDGING WILL TAKE HOLD BY MONDAY NIGHT AS ANOTHER STRONG 500MB CLOSED LOW BEGINS MOVING INTO THE NORTHERN PLAINS. AT THE SURFACE...ANOTHER COLD FRONT WILL PROTRUDE AHEAD OF THE SURFACE LOW...THIS ONE STRONGER AND PULLING IN DEEP WARM MOISTURE FROM THE GULF AS IT NEARS THE MISSISSIPPI RIVER VALLEY. MODELS ARE STILL IN SOMEWHAT OF A POOR AGREEMENT BY THIS POINT...WITH LITTLE CERTAINTY AS TO WHEN THE PRECIP WILL REACH THE ERN KY REGION. WILL CONTINUE WITH MODEL CONSENSUS FOR THIS EVENT...BUT DO EXPECT SOME PRECIP TO BEGIN MOVING IN BY TUESDAY EVENING. THE FRONT WILL SLOW AS IT REACHES KY...ALLOWING MOISTURE TO SLOWLY INCREASE AND CONTINUE THROUGH THURSDAY NIGHT. HIGH PRESSURE WILL SET IN FOR A VERY SHORT TIME PERIOD ON FRIDAY. HOWEVER...A SECONDARY FRONT WILL BEGIN PUSHING INTO THE REGION BY FRIDAY AFTERNOON. WITH LINGERING LOW LEVEL MOISTURE FROM THE PREVIOUS SYSTEM...ALONG WITH ISENTROPIC LIFT AS THE FRONT PASSES...EXPECT MORE SHOWERS TO DEVELOP BY SATURDAY AFTERNOON ACCORDING TO THE LATEST ECMWF. TEMPERATURES WILL FINALLY DROP DOWN TO MORE SEASONABLE /IF NOT SLIGHTLY BELOW/ AFTER THE PASSAGE OF THE COLD FRONT ON THURSDAY...AND REMAIN SO THROUGH THE REMAINDER OF THE FORECAST PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 758 AM EDT SAT OCT 12 2013 LOW CLOUDS WITH MVFR AND IFR CEILINGS WERE SPREADING WESTWARD INTO THE FORECAST AREA EARLY THIS MORNING. WEST OF THE CLOUD DECK... VALLEY FOG WAS PREVALENT NEAR RIVERS...LAKES...AND LARGE STREAMS... BRINGING AREAS OF VLIFR. THE FOG WILL DISSIPATE THIS MORNING. THE CLOUD DECK IS EXPECTED TO CONTINUE A SLOW WESTWARD PROGRESSION...BUT ALSO SLOWLY RISE AND BEGIN TO BREAK UP WITH TIME TODAY...GIVING WAY TO MAINLY VFR THIS AFTERNOON. VALLEY FOG SHOULD DEVELOP AGAIN LATE TONIGHT...BUT WILL LIKELY BE TEMPERED BY CLOUDS IN THE EASTERN PART OF THE AREA. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JP SHORT TERM...HAL LONG TERM...JMW AVIATION...HAL
AREA FORECAST DISCUSSION
NWS JACKSON KY
758 AM EDT SAT OCT 12 2013 .UPDATE... ISSUED AT 758 AM EDT SAT OCT 12 2013 LOW CLOUDS HAVE MADE THEIR WAY INTO THE FORECAST AREA FROM THE EAST. THE RUC BRINGS THEM A BIT FURTHER WEST THIS MORNING BEFORE THEY BEGIN TO BREAK UP FOR THE AFTERNOON...AND THIS HAS BEEN DEPICTED IN THE UPDATED FORECAST GRIDS. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 400 AM EDT SAT OCT 12 2013 A DYING AREA OF LOW PRESSURE WHICH HAS BEEN SITUATED TO OUR EAST FOR DAYS IS PROVIDING A MEAGER AMOUNT OF LOW-MID LEVEL MOISTURE TO OUR EASTERN COUNTIES. THIS LED TO PERIODS OF LOW CLOUDS DURING THE NIGHT. WITH DAYTIME HEATING...IT MAY ALSO BE ENOUGH FOR A FEW LIGHT SHOWERS TO DEVELOP THIS AFTERNOON...AND WILL USE A 20 PERCENT POP OVER THE EASTERN TIP OF THE STATE. WILL LOOK FOR ANY PRECIP TO END AS TEMPS COOL DOWN AGAIN TONIGHT. A DYING COLD FRONT WILL PUSH IN FROM THE WEST ON SUNDAY...AND WITH RESIDUAL LOW-MID LEVEL MOISTURE FROM THE LOW...THERE WILL BE A POSSIBILITY OF SHOWERS. WILL NOT INCLUDE ANY THUNDER THIS WEEKEND...SINCE THE CONVECTION LOOKS LIKE IT WILL BE CAPPED BELOW THE -20C LEVEL. WE WILL SEE VALLEY FOG IN SOME LOCATIONS THIS MORNING AND AGAIN TONIGHT INTO SUNDAY MORNING. IT WILL BE LIMITED IN EASTERN AREAS WHERE CLOUDS ARE MORE SIGNIFICANT. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 413 AM EDT SAT OCT 12 2013 BY 0Z MONDAY...UPPER LEVEL PATTERN WILL START OFF IN A GOOD AGREEMENT...WITH AN UPPER LEVEL RIDGE AXIS EXITING EAST OF THE APPALACHIANS...A WEAK CLOSED LOW OFF THE NORTH CAROLINA COAST...AND A STRONGER CLOSED LOW ENTERING THE HUDSON BAY IN CENTRAL CANADA. THE LOW IN CANADA WILL BE THE MAIN CONCERN DURING THE MID-TERM...AS IT WILL ESTABLISH A STRONG SURFACE LOW AND AN ASSOCIATED COLD FRONT WHICH IS POISED TO MOVE THROUGH WESTERN AND CENTRAL KY DURING THE DAY SUNDAY /DURING THE SHORT TERM PERIOD/. BY THE START OF THE EXTENDED FORECAST...THIS FRONT WILL BE MOVING THROUGH AND EXITING EASTERN KY. LATEST MODEL RUNS ARE STILL SUPPORTING THE IDEA OF LIGHT RAIN SHOWERS CONTINUING SUNDAY EVENING INTO SUNDAY NIGHT...BUT ALL RUNS ARE NOW IN AGREEMENT THAT SOME OF THESE ISOLATED SHOWERS COULD LINGER ACROSS ERN KY INTO MONDAY AS WELL. ADDED IN SOME MARGINAL SLIGHT CHANCE POPS MONDAY TO ACCOUNT FOR THIS. SHORT TERM RIDGING WILL TAKE HOLD BY MONDAY NIGHT AS ANOTHER STRONG 500MB CLOSED LOW BEGINS MOVING INTO THE NORTHERN PLAINS. AT THE SURFACE...ANOTHER COLD FRONT WILL PROTRUDE AHEAD OF THE SURFACE LOW...THIS ONE STRONGER AND PULLING IN DEEP WARM MOISTURE FROM THE GULF AS IT NEARS THE MISSISSIPPI RIVER VALLEY. MODELS ARE STILL IN SOMEWHAT OF A POOR AGREEMENT BY THIS POINT...WITH LITTLE CERTAINTY AS TO WHEN THE PRECIP WILL REACH THE ERN KY REGION. WILL CONTINUE WITH MODEL CONSENSUS FOR THIS EVENT...BUT DO EXPECT SOME PRECIP TO BEGIN MOVING IN BY TUESDAY EVENING. THE FRONT WILL SLOW AS IT REACHES KY...ALLOWING MOISTURE TO SLOWLY INCREASE AND CONTINUE THROUGH THURSDAY NIGHT. HIGH PRESSURE WILL SET IN FOR A VERY SHORT TIME PERIOD ON FRIDAY. HOWEVER...A SECONDARY FRONT WILL BEGIN PUSHING INTO THE REGION BY FRIDAY AFTERNOON. WITH LINGERING LOW LEVEL MOISTURE FROM THE PREVIOUS SYSTEM...ALONG WITH ISENTROPIC LIFT AS THE FRONT PASSES...EXPECT MORE SHOWERS TO DEVELOP BY SATURDAY AFTERNOON ACCORDING TO THE LATEST ECMWF. TEMPERATURES WILL FINALLY DROP DOWN TO MORE SEASONABLE /IF NOT SLIGHTLY BELOW/ AFTER THE PASSAGE OF THE COLD FRONT ON THURSDAY...AND REMAIN SO THROUGH THE REMAINDER OF THE FORECAST PERIOD. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 758 AM EDT SAT OCT 12 2013 LOW CLOUDS WITH MVFR AND IFR CEILINGS WERE SPREADING WESTWARD INTO THE FORECAST AREA EARLY THIS MORNING. WEST OF THE CLOUD DECK... VALLEY FOG WAS PREVALENT NEAR RIVERS...LAKES...AND LARGE STREAMS... BRINGING AREAS OF VLIFR. THE FOG WILL DISSIPATE THIS MORNING. THE CLOUD DECK IS EXPECTED TO CONTINUE A SLOW WESTWARD PROGRESSION...BUT ALSO SLOWLY RISE AND BEGIN TO BREAK UP WITH TIME TODAY...GIVING WAY TO MAINLY VFR THIS AFTERNOON. VALLEY FOG SHOULD DEVELOP AGAIN LATE TONIGHT...BUT WILL LIKELY BE TEMPERED BY CLOUDS IN THE EASTERN PART OF THE AREA. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...HAL LONG TERM...JMW AVIATION...HAL
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
957 PM EDT SUN OCT 13 2013 .SYNOPSIS... STRONG HIGH PRESSURE WILL SLOWLY PUSH OFF THE NEW ENGLAND COAST THROUGH TUESDAY...AS A TROUGH OF LOW PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST. AS A RESULT...NORTHEAST WINDS WILL CONTINUE TO BRING MAINLY CLOUDY AND DAMP CONDITIONS INTO MONDAY MORNING. A SLOW DRYING TREND IS EXPECTED MONDAY AFTERNOON THROUGH TUESDAY...AS A PORTION OF THE HIGH RIDGES SOUTH INTO THE NORTHERN MID ATLANTIC REGION. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST LATE WEDNESDAY INTO THURSDAY. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... THE LATEST SURFACE ANALYSIS SHOWS A 1015MB LOW PRESSURE CENTER OFF THE NC/SC COAST WITH A STEADY PRESSURE TENDENCY. MEANWHILE...A ~1030MB SFC HIGH PRESSURE ANCHORED ALONG THE COAST OF SOUTHERN COAST OF MAINE IS SLOWLY BUILDING SSW INTO THE MID ATLANTIC REVEALED BY +2MB/3HR PRESSURE RISES ACROSS THE REGION. ALOFT...A MID-LEVEL LOW CONTINUES TO LINGER OFF THE COAST ABOVE THE SURFACE REFLECTION OF THE LOW. THE PRIMARY MOIST FRONTAL BAND (DOWNSTREAM OF THE LOW) IS WELL OFF THE COAST OVER THE SUBTROPICAL WESTERN ATLANTIC. HOWEVER...A MOIST AIRSTREAM CONTINUES TO FLOW WESTWARD TOWARD THE LOCAL AREA...WITH IR SATELLITE ENHANCEMENT SUGGESTING SOME LIFT WITHIN THIS AIRSTREAM. THE LATEST RUC BRINGS THIS LIFT INTO NE NC/FAR SE VA LATE TONIGHT INTO EARLY MONDAY...SO A PERIOD OF LIKELY AND CATEGORICAL RAIN HAS BEEN INTRODUCED. OTHERWISE...AREAS OF LIGHT RAIN AND DRIZZLE SHOULD PERSIST OVERNIGHT MAINLY ACROSS SOUTHERN AND WESTERN PORTIONS. WITH NE FLOW REMAINING BREEZY...LOWS WILL AVG 60-65 OVER SE VA/NE NC ...MID- UPPER 50S NW. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... MON WILL GENLY BEGIN CLOUDY AND DAMP ONCE AGAIN...BUT SLOW DRYING FROM THE NNE WILL BEGIN THROUGH THE DAY. MDL TIME SECTIONS (WHICH GENERALLY HOLD ONTO MSTR UP TO 3-4K FT) WILL HANG ONTO CLDY/DAMP CONDS WELL THROUGH THE DAY MON ACRS SRN VA/NE NC...WHILE SKIES BECOME PARTLY SUNNY ACRS THE NORTH. HIGHS GENLY CLOSE TO 70 F THROUGHOUT. WK REFLECTION OF LO PRES LINGERS INVOF CSTL NC...AND SFC HI PRES NNE OF THE RGN WKNS MON NGT THROUGH TUE. THEREFORE...CONFIDENCE IN PRONOUNCED CLRG...ESP ACRS SRN VA/NE NC...RMNG QUITE LOW. THERE IS NO MECHANISM TO SCOUR OUT THE LO LVL MSTR...AND CONCERNED THAT WHILE THERE WILL LIKELY BE SOME PROGRESS (OR TREND) TOWARD CLRG ERY IN THE WK...LO CLDS WILL BE DIFFICULT TO DISLODGE (OR EVEN IF THERE IS CLRG ON MON IN SOME PLACES - CLDS RETURN MON NGT AND/OR TUE). RA CHCS XPCD TO BE LWR FOR TUE...HWVR...WOULD NOT RULE OUT AT LEAST PTCHY DZ CONTG ACRS THE SE. INCREASING CLOUDINESS FROM THE W TUE NIGHT/WED AS THE SFC RIDGE WEAKENS. WILL SEE PARTLY TO MOSTLY CLOUDY SKIES WED W/ HIGHS 70-75. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... WSW FLOW ALOFT BEGINS TO INCREASE AHEAD OF THE NEXT SYSTEM PUSHING FROM THE UPPER MIDWEST TO THE GREAT LAKES ON WED CAUSING THE SFC RIDGING ASSOCIATED WITH HIGH PRESSURE OFF THE NEW ENGLAND COAST TO WEAKEN. LATEST ECMWF/GFS IN GOOD AGREEMENT THROUGH EARLY FRI SHOWING POTENTIAL FOR MOISTURE AND CLOUDS AS COLD FRONT APPROACHES THE AREA FROM THE WEST. DIFFERENCES BETWEEN THE MODELS BEGIN TO ARISE FRI NIGHT AS GFS SWEEPS THE FRONT THROUGH THE AREA WHILE THE ECMWF STALLS THE FRONT OVER THE AREA. TRENDED TOWARDS THE ECMWF DUE TO TRENDS LATELY IN WHICH COLD FRONTS STRUGGLE TO BE ABLE TO PUSH THEIR WAY COMPLETELY THROUGH THE AREA AND OFF THE COAST. WITH THE FRONT STALLING AROUND THE AREA EXPECT WARMER TEMPS BUT WITH A CLOUDIER/WETTER FORECAST. STRONGEST DYNAMICS STAY WELL TO OUR NW SO WILL ONLY CARRY A 30% POP THU THROUGH FRI MORNING FOR NOW. TEMPS WILL BE CLOSE TO AVG BY DAY WITH HIGHS MAINLY 70-75 AND A BIT ABOVE AVG AT NIGHT WITH LOWS IN THE LOW 50S TO AROUND 60 SE COAST. BY SAT...ECMWF SHOWS ANOTHER FRONT APPROACHING FROM THE WEST AS THE MID LEVEL FLOW REMAINS FROM THE SW AGAIN BRINGING THE POSSIBILITY FOR ANOTHER ROUND OF PRECIP. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... STRONG NE FLOW WILL CONTINUE OVER THE REGION THROUGH MON DUE TO COMBINATION OF STRONG HI PRES BLDNG OVR NEW ENGLAND AND A WEAK AREA OF LO PRES OFF THE MID ATLC AND SE COAST. MAINLY IFR/MVFR CIGS AND OCNL -RA/-DZ WILL PERSIST OVR THE TAF SITES INTO MON MORNG...EXCEPT POSSIBLY SBY WHERE DRIER AIR BEGINS TO MOVE IN AND MVFR/VFR CONDITIONS COULD PREVAIL BY LATE TONIGHT. MODELS SUGGEST AREA OF RAIN FROM THE ATLANTIC WILL AFFECT SE VA/NE NC LATE TONIGHT AND INTO EARLY MON. SURFACE WINDS WILL REMAIN NORTH- EASTERLY...BUT UPR LVL WIND FROM THE NNW SHOULD RESULT IN IMPROVING CONDITIONS FOR LATER MON AND TUE. && .MARINE... SOLID SCA CONDITIONS CONTINUE AS TIGHT PRESSURE GRADIENT REMAINS OVER THE WATERS. STRONG 1031 MB SFC HIGH PRESSURE (+1 STD DEV MSLP) WILL CONTINUE TO BUILD OVER THE NE STATES AS THE PERSISTENT SFC LOW OF THE PAST SEVERAL DAYS WILL DRIFT SWD...LOCATING JUST OFF THE SE NC COAST. NE WINDS HAVE INCREASED AS THE STRONGEST LOW LEVEL WINDS TRANSITION SWD OVER THE WATERS. GOOD LOW LEVEL GRADIENT WILL MIX THESE STRONGER WINDS TO THE WATER...WITH GUSTS UP TO 28 KT ALREADY OBSERVED OVER THE CNTRL BAY AND NRN COASTAL ZONES. HIGHER PLATFORMS...INCLUDING THE CBBT...HAVE REACHED 30 KT. STRONG WINDS HAVE BUILT WAVES TO 4-5 FT IN THE BAY AND 6 TO 10 FT OVER THE COASTAL WATERS. HIGH PRESSURE WILL SETTLE OFF THE NE COAST MON AS A WEAK COASTAL TROUGH REMAINS OFF THE COAST. GRADIENT WILL BEGIN TO RELAX OVER THE NRN WATERS...BUT SCA CONDITIONS WILL CONTINUE OVER THE SRN BAY AS NE WINDS REMAIN 15 TO 20 KT AND WAVES 3-4 FT. SEAS WILL SUBSIDE TO NEAR 5-6 FT OVER THE NRN COASTAL ZONES...AS SEAS IN THE SRN ZONES BUILD TO 6-9 FT. HIGH PRESSURE WILL MOVE EWD AWAY FROM THE NE COAST TUES...ALLOWING THE GRADIENT TO RELAX OVER THE WATERS AND NE WINDS TO FINALLY FALL BELOW SCA SPEEDS. HOWEVER...PERSISTENT NE WINDS WILL KEEP SEAS HIGH (5-6 FT) AND SCA HEADLINES THRU LATE TUES. WILL ALSO KEEP SCA HEADLINES IN THE MOUTH OF THE BAY AS 4 FT WAVES ARE FORECAST. HIGH SEAS WILL LIKELY CONTINUE INTO WEDS...BUT CONDITIONS OVER THE BAY/RIVER/SOUND WILL BE FAVORABLE WITH ELY WINDS GENERALLY BELOW 10 KT. A COLD FRONT WILL APPROACH THE WATERS WEDS NIGHT-THURS MORNING. && .TIDES/COASTAL FLOODING... STRONG NE WINDS WILL CONTINUE TO RESULT IN 1 TO 1.5 FOOT (APPROACHING 2 FT ALONG THE COASTAL ERN SHORE DUE TO NEAR GALE FORCE WINDS) TIDAL ANOMALIES THROUGH THE OVERNIGHT. HAVE EXTENDED ALL HEADLINES THROUGH MONDAY MORNINGS HIGH TIDE CYCLES AS MINOR COASTAL FLOODING IS EITHER IMMINENT...OR CONFIDENCE OF REACHING MINOR FLOOD LEVELS IS HIGH. STRONG NE WINDS OVER THE BAY MAY PUSH WATER LEVELS TO NEAR MODERATE THRESHOLDS AT WINDMILL POINT AND THE LOWER NRN NECK MONDAY MORNING. ADVISORY LEVEL FLOODING IS POSSIBLE AGAIN DURING MONDAYS HIGH TIDE CYCLES. SEE CFWAKQ FOR MORE SITE- SPECIFIC TIDAL INFORMATION. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...COASTAL FLOOD ADVISORY UNTIL 10 AM EDT MONDAY FOR MDZ024-025. COASTAL FLOOD ADVISORY UNTIL 3 PM EDT MONDAY FOR MDZ021>023. NC...NONE. VA...COASTAL FLOOD ADVISORY UNTIL NOON EDT MONDAY FOR VAZ075>078- 081-082-084>086-089>091-093-094-096-097. COASTAL FLOOD ADVISORY UNTIL 8 AM EDT MONDAY FOR VAZ095-098. COASTAL FLOOD ADVISORY UNTIL 10 AM EDT MONDAY FOR VAZ099-100. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR ANZ634-650-652- 654-656-658. SMALL CRAFT ADVISORY UNTIL NOON EDT MONDAY FOR ANZ630-631-636- 637. SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ635. SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ632. SMALL CRAFT ADVISORY UNTIL NOON EDT TUESDAY FOR ANZ633. SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ638. && $$ SYNOPSIS...LKB NEAR TERM...AJZ/LKB SHORT TERM...ALB/LKB LONG TERM...DAP AVIATION...DAP/JEF MARINE...SAM TIDES/COASTAL FLOODING...AKQ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
113 PM EDT SUN OCT 13 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 511 AM EDT SUN OCT 13 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A TROF EXTENDING FROM CNTRL CANADA TO THE WRN CONUS. WITHIN THE TROF...A MID LEVEL LOW WAS OVER NE MANITOBA...AND A RATHER VIGOROUS SHORTWAVE WAS LIFTING NE OF LAKE SUPERIOR. BEHIND WAVE...BKN/OVC STRATOCU IS SPREADING S AND E ACROSS WRN UPPER MI. WHILE REGIONAL RADARS SHOW SOME -SHRA OVER FAR NRN LAKE SUPERIOR INTO NRN ONTARIO...THERE ARE HINTS OF A FEW -SHRA/SPRINKLES FARTHER W INTO NE MN. IN FACT...A FEW OBS HAVE REPORTED PCPN RECENTLY. WITH CYCLONIC FLOW THIS MORNING AND PRESENCE OF SOME SPRINKLES UPSTREAM YET...OPTED TO INCLUDE SCT SPRINKLES OVER PORTIONS OF NRN UPPER MI THIS MORNING. IN ADDITION TO THE CLOUD COVER SPREADING ACROSS WRN UPPER MI...DAYTIME HEATING WILL LIKELY RESULT IN AN EXPANSION OF STRATOCU THIS MORNING ACROSS MUCH OF THE AREA. ADVECTION OF DRIER AIR AND INCREASINGLY ANTICYCLONIC FLOW THIS AFTN SHOULD THEN LEAD TO CLEARING FROM W TO E. EXPECT HIGHS IN THE 50S. SFC HIGH PRES SETTLING OVER THE WRN GREAT LAKES TONIGHT COMBINED WITH PRECIPITABLE WATER 50-60PCT OF NORMAL WILL SUPPORT EXCELLENT RADIATIONAL COOLING TONIGHT. HIGH CLOUDS SPREADING INTO THE AREA OVERNIGHT WILL LIMIT TEMP FALL...BUT TEMPS WILL HAVE A GOOD OPPORTUNITY TO PLUMMET AT LEAST THRU THE EVENING HRS BEFORE HIGH CLOUDS MAY HAVE SOME IMPACT. AS IN RECENT DAYS...WILL CONTINUE TO FAVOR THE LOW END OF AVBL GUIDANCE WHICH CONTINUES TO BE REPRESENTED BY THE BIAS CORRECTED GEM (OFTEN IT DOES A NICE JOB HANDLING RADIATIONAL COOLING NIGHTS). EXPECT TRADITIONAL COLD SPOTS TO FALL INTO THE MID/UPPER 20S. IF TEMP TONIGHT/MON MORNING DOES NOT FALL TO FREEZING OR LOWER HERE AT NWS MQT...THIS YEAR WILL SET THE RECORD FOR THE LATEST OCCURRENCE IN AUTUMN OF A MIN TEMP AT OR BLO FREEZING. CURRENT RECORD WAS SET IN 1997. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 511 AM EDT SUN OCT 13 2013 PERIOD STARTS 12Z MON WITH A SFC HIGH OVER THE CWA WITH 850MB TEMPS AROUND 2C. SUNNY SKIES TO START THE DAY OUT WILL ALLOW TEMPS TO INITIALLY WARM UP...BUT A LOW PRESSURE SYSTEM SPINNING UP OVER THE CENTRAL PLAINS WILL MAKE SOME PROGRESS TOWARD THE AREA THROUGH THE DAY. THIS WILL BRING INCREASING COVERAGE OF UPPER LEVEL CLOUDS INTO THE CWA AND PUSH THE SFC HIGH E...WHICH WILL CAP HIGH TEMPS IN THE MID TO UPPER 50S. AS THE LOW MOVES TO SRN MN BY 12Z TUE...FGEN FORCING AND SOME ELEVATED INSTABILITY AROUND 600MB WILL MOVE INTO OR NEAR THE FAR WRN CWA LATE MON EVENING AND WILL REMAIN THROUGH MON NIGHT. INITIALLY...THINK THAT DRY LOW LEVELS...AS INDICATED BY NAM AND GFS FORECAST SOUNDINGS...WILL KEEP PRECIP AT BAY UNTIL LATER MON NIGHT. WILL CONTINUE TO HAVE POPS INCREASING OVER THE WRN CWA MON NIGHT AS THE SYSTEM MOVES CLOSER...INCREASING OVERALL SYNOPTIC SUPPORT WITH INCREASINGLY SATURATED LOW LEVELS. THE LOW THEN MOVES TO CENTRAL WI BY 00Z WED...THEN TO NRN LOWER MI /OR POSSIBLY FARTHER NE AS INDICATED BY THE 12Z/12 ECMWF/ BY 12Z WED...WITH THE ASSOCIATED UPPER TROUGH AXIS MOVING FROM JUST W OF THE CWA AT 00Z WED TO THE CENTRAL CWA BY 12Z WED AND E OF THE CWA BY 00Z THU. 850MB TEMPS ON THE N SIDE OF THE SFC LOW /AND AHEAD OF THE UPPER TROUGH/ WILL VARY FROM 3C TO 5 C OVER THE SRN CWA TO AROUND -1 OVER NRN LAKE SUPERIOR. RIGHT NOW...THE ECMWF AND GFS /WHICH ARE THE MORE TRUSTED MODELS/ HAVE QPF SPREADING ACROSS THE ENTIRE CWA BY TUE EVENING...AND HAVE HIGH CONFIDENCE IN THAT SO WILL BE INCREASING POPS. WHAT WILL BE A BIT HARDER TO FORECAST IS WHERE HEAVIEST RAIN WILL FALL. MODELS CURRENTLY SHOW LOW LEVEL FGEN BANDING ORIENTED W-E OVER UPPER MI...WHICH WOULD PRODUCE MORE INTENSE RAINFALL. OF COURSE...ESPECIALLY LOW LEVEL...FGEN BAND LOCATION FORECASTING THIS FAR OUT IS HAPHAZARD AS THAT BAND MAY BE FARTHER N OR S. THE BAND LOOKS AS THOUGH IT WILL STAY IN PLACE UNTIL THE UPPER TROUGH SHIFTS THROUGH LATER TUE NIGHT...POSSIBLY PRODUCING 24 HOUR QPF TOTALS TUE AND TUE NIGHT OF AN INCH OR GREATER IN ANY PLACES THAT SIT UNDER THE FGEN BAND FOR A LONGER PERIOD OF TIME. TEMPS FOR TUE LOOK A BIT COOLER THAN MON WITH THE GREATER CLOUD COVER AND RAIN...WITH HIGHS IN THE LOW TO MID 50S. FOR WED...STILL GOING WITH THE 00Z/13 GFS AND 12Z/12 ECMWF /AND SOMEWHAT WITH THE 00Z/13 GLOBAL GEM/ WHICH ARE IN GOOD GENERAL AGREEMENT. THE 12Z/12 AND 00Z/12 ECMWF WERE BOTH SHOWING THE LOW MOVING THROUGH WED INSTEAD OF TUE/TUE NIGHT...BUT THE LATEST RUNS ALL AGREE IN KEEPING THE SYSTEM MORE PROGRESSIVE. SO...WED SHOULD SEE PRECIP CLEARING TO THE E AS SHORTWAVE HIGH PRESSURE MOVES OVERHEAD BY LATE AFTERNOON INTO THE EVENING. WILL NOT CHANGE THE FORECAST COMPLETELY JUST YET...EVEN THOUGH IT HAS 50-60 POPS OVER MUCH OF UPPER MI WED...SINCE MODELS MAY AGAIN CHANGE AND AM WEARY OF GOING 100 PERCENT WITH JUST THE LATEST MODEL RUNS. THINK THAT A 50/50 BLEND OF NEW MODEL DATA AND PREVIOUS FORECAST WILL COVER THINGS ADEQUATELY FOR POPS. TEMPS LOOK SIMILAR TO TUE WITH HIGHS FROM AROUND 50 TO THE MID 50S. THE FORECAST BEYOND WED IS MORE UNCERTAIN WITH EXACT DETAIL...BUT GAINING CONFIDENCE ON THE OVERALL GENERAL PATTERN. DO AGREE WITH PREVIOUS SHIFT THAT DRIER FORECAST FOR THU LOOKS TO BE IN ORDER...BUT NOT READY TO GO COMPLETELY DRY JUST YET. PREVIOUS RUNS OF THE MODELS THAT HAD THE LOW BEING SLOWER MADE FOR A MUCH WETTER THU...BUT NEWER RUNS SEEM IN DECENT AGREEMENT KEEPING SIGNIFICANT PRECIP OUT OF THE CWA FOR AT LEAST THE FIRST HALF OF THE DAY THU. WILL GO WITH A CONSENSUS OF GUIDANCE FOR NOW. THE GENERAL TREND THROUGH SAT IS THAT A FEW PIECES OF ENERGY WILL MOVE THROUGH THE AREA AS A LARGE SCALE UPPER TROUGH INCREASINGLY DOMINATES THE CENTRAL/ERN CONUS. MODELS EVEN AGREE FAIRLY WELL WITH SHOWING 850MB TEMPS FALLING AS LOW AS -7C BY LATE SAT. SYNOPTIC ENERGY FLOWING AROUND THE TROUGH MAY LEAD TO PERIODS OF PRECIP...WITH LAKE ENHANCEMENT AS TEMPS GET COOLER...BUT WITH EXACT DETAILS OF WIND DIRECTION AND TIMING OF ENERGY IT IS HARD TO GET TOO SPECIFIC WITH POPS. DO BELIEVE THAT FIRST CHANCES OF SNOW WILL BE POSSIBLE IN THE FAR EXTENDED...AND WILL CONTINUE TO SHOW SOME MIXED PRECIP IN THE FORECAST AS DID THE PREVIOUS SHIFT. THE MORE CERTAIN ASPECT OF THIS PART OF THE FORECAST IS THAT TEMPS WILL BE QUITE A BIT COOLER WITH HIGHS IN THE 40S /AND MAYBE EVEN SOME UPPER 30S HIGHS/ ON SAT. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 107 PM EDT SUN OCT 13 2013 OTHER THAN BKN MVFR STRATOCU AT KIWD AND KSAW THROUGH 21Z...EXPECT VFR CONDITIONS AT ALL TAF SITES AS SFC HIGH PRES DOMINATES. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 511 AM EDT SUN OCT 13 2013 W TO NW WINDS OF 15-30KT WILL GRADUALLY SUBSIDE TODAY AS PRES GRADIENT RELAXES BTWN LOW PRES OVER HUDSON BAY AND HIGH PRES APPROACHING FROM THE PLAINS. LATE TONIGHT THRU AT LEAST MON MORNING...THE HIGH WILL BE OVER THE AREA...RESULTING IN LIGHT WINDS UNDER 15KT. EASTERLY WINDS WILL THEN BEGIN TO INCREASE FROM W TO E LATE MON AFTN THRU TUE AS THE HIGH SHIFTS TO NEW ENGLAND AND LOW PRES LIFTS FROM THE WRN PLAINS TOWARD THE WRN GREAT LAKES. BY TUE AFTN...E TO NE WINDS WILL BE INTO THE 20-30KT RANGE OVER WRN LAKE SUPERIOR. THESE STRONGER WINDS WILL SPREAD INTO MUCH OF CNTRL AND ERN LAKE SUPERIOR TUE NIGHT. WINDS WILL THEN DIMINISH TO UNDER 20KT W TO E WED/THU AS THE LOW EXITS TO THE E. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...TITUS AVIATION...VOSS MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1238 PM CDT SAT OCT 12 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 415 AM CDT SAT OCT 12 2013 SFC LOW AT 3 AM WAS NEAR WINNIPEG WITH THE COLD FRONT JUST MOVING INTO EAU CLAIRE AND LADYSMITH. 24 HOUR TEMP CHANGE ACROSS WRN MN AROUND 15 DEGS COLDER AND THAT PRETTY MUCH SUMS UP THE CURRENT FORECAST FOR HIGHS TODAY...TAKE WHAT YOU HAD YESTERDAY MINUS 15. THIS WILL BRING AN ABRUPT END TO OUR RUN OF 4 STRAIGHT DAYS WITH TEMP ANOMALIES GREATER THAN 10 DEGREES ABOVE NORMAL. ON WATER VAPOR THIS MORNING...YOU CAN SEE A DEVELOPING TROWAL FEATURE SOUTH OF THE SFC LOW OVER SODAK. THIS IS IN ASSOCIATION WITH A STRONG PV ANOMALY ROTATING AROUND THE SOUTH SIDE OF THE SYSTEM NEAR WINNIPEG. SHOWERS TODAY WILL BE FOUND ON THE WEST SIDE OF THIS TROWAL...TO THE NW OF THE CENTER OF THE PV ANOMALY. THE RAP DOES NOT SHOW THIS DEFORMATION BAND OF PRECIP MOVING INTO WC MN UNTIL 15Z..THEN TRACKS IT NE ACROSS CENTRAL MN DURING THE DAY. KEPT POP MAGNITUDE RELATIVELY UNCHANGED AT 30-40 PERCENT ACROSS NRN PORTIONS OF THE MN CWA...JUST DELAYED ITS MOVEMENT INTO AND THROUGH CENTRAL MN TODAY. TONIGHT...HIGH PRESSURE CURRENTLY CENTERED FROM NW KANSAS BACK THROUGH MONTANA WILL DRIFT E AND SETTLE IN FROM CENTRAL ILLINOIS BACK INTO NODAK BY SUNDAY MORNING. AS THIS HIGH PRESSURE MOVES IN...IT WILL BRING WITH IT A SIGNIFICANT REDUCTION IN DEWPS...WHICH COULD FALL INTO THE 20S SOUTH OF THE MN RIVER THIS AFTERNOON...WITH 30S OVERSPREADING THE REST OF THE AREA TONIGHT. THIS DRY AIR WILL COMBINE WITH CLEAR SKIES AND A SLACKENING OF THE WINDS TO PROMOTE GOOD RADIATIONAL COOLING TONIGHT. JUST ABOUT EVERYONE SHOULD FIND THEMSELVES FALL INTO THE 30S BY SUNDAY MORNING...WITH A FEW SPOTS FROM SW MN UP THROUGH CENTRAL MN HAVING THE POTENTIAL TO PICK UP THEIR FIRST 32 OR COLDER LOW THIS SEASON. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 415 AM CDT SAT OCT 12 2013 SUNDAY WILL BE A NEAR PERFECT FALL DAY ACROSS THE REGION WITH HIGH PRESSURE OVERHEAD... LOTS OF SUNSHINE... LIGHT WINDS AND LOW AFTERNOON HUMIDITY. THE PLEASANT WEATHER WILL FADE ON MONDAY AS RAIN GRADUALLY OVERSPREADS THE REGION. THE NAM/GFS REMAIN THE FASTEST ON BRINGING A LOW PRESSURE SYSTEM FROM THE CENTRAL PLAINS TO MN BY TUESDAY MORNING WHILE THE ECMWF/GEM DON/T HAVE THE LOW REACHING INTO MN UNTIL TUESDAY NIGHT. CONTINUITY OVER THE PAST FOUR NIGHTS IS BEST WITH THE ECMWF. THIS SOLUTION RECEIVED THE MOST WEIGHTING WITH REGARDS TO PRECIPITATION TIMING AND RAIN AMOUNTS FROM MONDAY THROUGH TUESDAY. HENCE...LIGHT RAIN WILL LIKELY SPREAD INTO WESTERN MN MONDAY MORNING AND SHOULD BE NEARING I-35 BY EVENING. THE RAIN WILL GRADUALLY SPREAD ACROSS WESTERN WI MONDAY NIGHT WHILE INCREASING IN INTENSITY OVER WEST CENTRAL MN WHERE DEEP LAYER MOISTURE...STRONG FORCING AND LOW LEVEL MOISTURE TRANSPORT IS MAXIMIZED. RAINFALL AMOUNTS MONDAY NIGHT ACROSS THE FAR WESTERN CWA MAY REACH OR EXCEED AN INCH. THERE IS ALSO A THREAT FOR THUNDERSTORMS MONDAY NIGHT/EARLY TUESDAY ACROSS SOUTH CENTRAL MN WHERE THE NOSE OF A NEGATIVE LI AXIS EXISTS. RAIN WILL BE ONGOING ACROSS THE FA TUESDAY MORNING... BUT A DRY SLOT WILL LIKELY POKE INTO SOUTHERN MN DURING THE DAY. THIS WILL KNOCK THE INTENSITY OF THE RAIN DOWN. EXTENSIVE CLOUDINESS/LIGHT RAIN WILL LINGER FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS THE LOW PRESSURE SYSTEM ADVANCES SLOWLY FROM MN TO THE WESTERN GREAT LAKES. HIGH TEMPERATURES WILL BE QUITE COOL FROM TUESDAY THROUGH THURSDAY WITH READINGS IN THE UPPER 40S TO MIDDLE 50S. THE END OF THE WORK WEEK WILL STILL BE COOL ALONG WITH QUITE A BIT OF CLOUDINESS AS TROUGHING ALOFT INCREASES ACROSS THE CENTER OF THE COUNTRY. THE ECMWF BECOMES A BIT EXTREME WITH THE UPPER TROUGH... STRETCHING FROM HUDSON BAY TO BAJA BY THE WEEKEND. WITH TIME... THE ECMWF DEEPENS THE UPPER TROUGH IN THE CENTER OF THE COUNTRY WITH A LOW PRESSURE SYSTEM RIDING NORTHEAST FROM THE SOUTHERN PLAINS TO THE LOWER GREAT LAKES. THIS SOLUTION PRODUCES SNOW ACROSS IA AND SOUTHERN WI NEXT SUNDAY. THE GEFS WOULD SPLIT THE UPPER TROUGH WITH ONE PORTION OVER THE EASTERN CONUS AND A CUT- OFF DEVELOPING IN THE SOUTHWEST. ON A SIDE NOTE...WE LEARNED FROM LAST WINTER THAT THESE TYPES OF SYSTEMS ON THE ECMWF TRENDED NORTHWARD WITH TIME. THE 7 TO 10 DAY PERIOD COULD BE INTERESTING. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1227 PM CDT SAT OCT 12 2013 MVFR CONDS OVER THE NORTHERN CWA THIS AFTERNOON...WITH ISOLD IFR CONDITIONS AS COLD CORE TROUGH LIFTS NORTHEAST THIS AFTERNOON. THIS WILL AFFECT MAINLY KAXN/KSTC. THE REST OF THE AREA WILL SEE SOME VFR CIGS 3-4K FEET. THEN CLEARING INTO THE EVENING. WEST/NORTHWEST WINDS SUSTAINED 15-25 WITH SOME GUSTS AROUND 30 KTS AT TIMES. EXPECT WINDS TO DIMINISH AS TROUGH EXITS TO THE NORTHEAST. WITH SURFACE RIDGE MOVING INTO THE WEST SHOULD SEE LIGHT WEST WINDS LESS THAN 10 KTS INTO SUNDAY. KMSP...CIGS AROUND 3-4K FEET THROUGH THE AFTERNOON SHOULD CLEAR INTO THE EVENING. SOME SPRINKLES ASSOCIATED WITH UPPER TROUGH TO THE WEST...BUT FEEL THEY WILL LIFT OFF TO THE NORTH THROUGH THE AFTERNOON. SURFACE WINDS SOUTHWEST TO WEST THIS AFTERNOON AND GUSTY. THEY SHOULD DIMINISH THIS EVENING AND BE LIGHT WEST INTO SUNDAY. /OUTLOOK FOR KMSP/ MON...VFR DURING DAY. MVFR/IFR WITH SHRA OVERNIGHT. WINDS E 10 KTS. TUE...MVFR/IFR WITH SHRA. WINDS NE 5 KTS. WED...MVFR. CHANCE SHRA. WINDS NW 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...RAH AVIATION...DWE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
520 AM CDT SAT OCT 12 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 415 AM CDT SAT OCT 12 2013 SFC LOW AT 3 AM WAS NEAR WINNIPEG WITH THE COLD FRONT JUST MOVING INTO EAU CLAIRE AND LADYSMITH. 24 HOUR TEMP CHANGE ACROSS WRN MN AROUND 15 DEGS COLDER AND THAT PRETTY MUCH SUMS UP THE CURRENT FORECAST FOR HIGHS TODAY...TAKE WHAT YOU HAD YESTERDAY MINUS 15. THIS WILL BRING AN ABRUPT END TO OUR RUN OF 4 STRAIGHT DAYS WITH TEMP ANOMALIES GREATER THAN 10 DEGREES ABOVE NORMAL. ON WATER VAPOR THIS MORNING...YOU CAN SEE A DEVELOPING TROWAL FEATURE SOUTH OF THE SFC LOW OVER SODAK. THIS IS IN ASSOCIATION WITH A STRONG PV ANOMALY ROTATING AROUND THE SOUTH SIDE OF THE SYSTEM NEAR WINNIPEG. SHOWERS TODAY WILL BE FOUND ON THE WEST SIDE OF THIS TROWAL...TO THE NW OF THE CENTER OF THE PV ANOMALY. THE RAP DOES NOT SHOW THIS DEFORMATION BAND OF PRECIP MOVING INTO WC MN UNTIL 15Z..THEN TRACKS IT NE ACROSS CENTRAL MN DURING THE DAY. KEPT POP MAGNITUDE RELATIVELY UNCHANGED AT 30-40 PERCENT ACROSS NRN PORTIONS OF THE MN CWA...JUST DELAYED ITS MOVEMENT INTO AND THROUGH CENTRAL MN TODAY. TONIGHT...HIGH PRESSURE CURRENTLY CENTERED FROM NW KANSAS BACK THROUGH MONTANA WILL DRIFT E AND SETTLE IN FROM CENTRAL ILLINOIS BACK INTO NODAK BY SUNDAY MORNING. AS THIS HIGH PRESSURE MOVES IN...IT WILL BRING WITH IT A SIGNIFICANT REDUCTION IN DEWPS...WHICH COULD FALL INTO THE 20S SOUTH OF THE MN RIVER THIS AFTERNOON...WITH 30S OVERSPREADING THE REST OF THE AREA TONIGHT. THIS DRY AIR WILL COMBINE WITH CLEAR SKIES AND A SLACKENING OF THE WINDS TO PROMOTE GOOD RADIATIONAL COOLING TONIGHT. JUST ABOUT EVERYONE SHOULD FIND THEMSELVES FALL INTO THE 30S BY SUNDAY MORNING...WITH A FEW SPOTS FROM SW MN UP THROUGH CENTRAL MN HAVING THE POTENTIAL TO PICK UP THEIR FIRST 32 OR COLDER LOW THIS SEASON. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 415 AM CDT SAT OCT 12 2013 SUNDAY WILL BE A NEAR PERFECT FALL DAY ACROSS THE REGION WITH HIGH PRESSURE OVERHEAD... LOTS OF SUNSHINE... LIGHT WINDS AND LOW AFTERNOON HUMIDITY. THE PLEASANT WEATHER WILL FADE ON MONDAY AS RAIN GRADUALLY OVERSPREADS THE REGION. THE NAM/GFS REMAIN THE FASTEST ON BRINGING A LOW PRESSURE SYSTEM FROM THE CENTRAL PLAINS TO MN BY TUESDAY MORNING WHILE THE ECMWF/GEM DON/T HAVE THE LOW REACHING INTO MN UNTIL TUESDAY NIGHT. CONTINUITY OVER THE PAST FOUR NIGHTS IS BEST WITH THE ECMWF. THIS SOLUTION RECEIVED THE MOST WEIGHTING WITH REGARDS TO PRECIPITATION TIMING AND RAIN AMOUNTS FROM MONDAY THROUGH TUESDAY. HENCE...LIGHT RAIN WILL LIKELY SPREAD INTO WESTERN MN MONDAY MORNING AND SHOULD BE NEARING I-35 BY EVENING. THE RAIN WILL GRADUALLY SPREAD ACROSS WESTERN WI MONDAY NIGHT WHILE INCREASING IN INTENSITY OVER WEST CENTRAL MN WHERE DEEP LAYER MOISTURE...STRONG FORCING AND LOW LEVEL MOISTURE TRANSPORT IS MAXIMIZED. RAINFALL AMOUNTS MONDAY NIGHT ACROSS THE FAR WESTERN CWA MAY REACH OR EXCEED AN INCH. THERE IS ALSO A THREAT FOR THUNDERSTORMS MONDAY NIGHT/EARLY TUESDAY ACROSS SOUTH CENTRAL MN WHERE THE NOSE OF A NEGATIVE LI AXIS EXISTS. RAIN WILL BE ONGOING ACROSS THE FA TUESDAY MORNING... BUT A DRY SLOT WILL LIKELY POKE INTO SOUTHERN MN DURING THE DAY. THIS WILL KNOCK THE INTENSITY OF THE RAIN DOWN. EXTENSIVE CLOUDINESS/LIGHT RAIN WILL LINGER FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS THE LOW PRESSURE SYSTEM ADVANCES SLOWLY FROM MN TO THE WESTERN GREAT LAKES. HIGH TEMPERATURES WILL BE QUITE COOL FROM TUESDAY THROUGH THURSDAY WITH READINGS IN THE UPPER 40S TO MIDDLE 50S. THE END OF THE WORK WEEK WILL STILL BE COOL ALONG WITH QUITE A BIT OF CLOUDINESS AS TROUGHING ALOFT INCREASES ACROSS THE CENTER OF THE COUNTRY. THE ECMWF BECOMES A BIT EXTREME WITH THE UPPER TROUGH... STRETCHING FROM HUDSON BAY TO BAJA BY THE WEEKEND. WITH TIME... THE ECMWF DEEPENS THE UPPER TROUGH IN THE CENTER OF THE COUNTRY WITH A LOW PRESSURE SYSTEM RIDING NORTHEAST FROM THE SOUTHERN PLAINS TO THE LOWER GREAT LAKES. THIS SOLUTION PRODUCES SNOW ACROSS IA AND SOUTHERN WI NEXT SUNDAY. THE GEFS WOULD SPLIT THE UPPER TROUGH WITH ONE PORTION OVER THE EASTERN CONUS AND A CUT- OFF DEVELOPING IN THE SOUTHWEST. ON A SIDE NOTE...WE LEARNED FROM LAST WINTER THAT THESE TYPES OF SYSTEMS ON THE ECMWF TRENDED NORTHWARD WITH TIME. THE 7 TO 10 DAY PERIOD COULD BE INTERESTING. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 520 AM CDT SAT OCT 12 2013 WITH SFC LOW MOVING NEARLY DUE NORTH ACROSS SRN CANADA...POST FRONTAL STRATUS ACROSS WRN MN HAS STAYED PUT MOST OF THE NIGHT. STILL EXPECT IT TO HEAD EAST THIS MORNING...REACHING WRN WI BY THE AFTERNOON AS A STRONG SHORT WAVE MOVES FROM THE DAKOTAS ACROSS CENTRAL MN. FOLLOWED THE RAP/NAM FOR BRINGING THESE CLOUDS BACK ACROSS TERMINALS TODAY. ALSO FOLLOWED THE IDEA OF THE RAP WITH MVFR CIGS STAYING CONFINED TO CENTRAL MN...WITH CIGS WORKING INTO MSP/RNH/EAU BEING OF THE VFR VARIETY. GUSTY WINDS WILL RETURN BY 15Z...THOUGH OUT OF THE WSW TODAY. NOT EXPECTING GUSTS LIKE WERE SEEN FRIDAY...BUT SHOULD STILL SEE GUSTS UP NEAR 30 KTS IN WRN MN AND 25 KTS OVER IN WI THIS AFTERNOON. TONIGHT...HIGH PRESSURE ARRIVES AND WITH IT A SLACKENING OF THE WINDS AND A CLEARING OF THE SKIES. KMSP...MAY SEE A BRIEF MVFR CIG WHEN STRATUS MOVES BACK IN AROUND 17Z...OTHERWISE VFR CONDITIONS WILL PREVAIL. CONFIDENCE HIGH IN ALL OTHER ASPECTS OF THE TAF. /OUTLOOK FOR KMSP/ MON...VFR DURING DAY. MVFR/IFR WITH SHRA OVERNIGHT. WINDS E 10 KTS. TUE...MVFR/IFR WITH SHRA. WINDS NE 5 KTS. WED...MVFR. CHANCE SHRA. WINDS NW 5-10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...RAH AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
415 AM CDT SAT OCT 12 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 415 AM CDT SAT OCT 12 2013 SFC LOW AT 3 AM WAS NEAR WINNIPEG WITH THE COLD FRONT JUST MOVING INTO EAU CLAIRE AND LADYSMITH. 24 HOUR TEMP CHANGE ACROSS WRN MN AROUND 15 DEGS COLDER AND THAT PRETTY MUCH SUMS UP THE CURRENT FORECAST FOR HIGHS TODAY...TAKE WHAT YOU HAD YESTERDAY MINUS 15. THIS WILL BRING AN ABRUPT END TO OUR RUN OF 4 STRAIGHT DAYS WITH TEMP ANOMALIES GREATER THAN 10 DEGREES ABOVE NORMAL. ON WATER VAPOR THIS MORNING...YOU CAN SEE A DEVELOPING TROWAL FEATURE SOUTH OF THE SFC LOW OVER SODAK. THIS IS IN ASSOCIATION WITH A STRONG PV ANOMALY ROTATING AROUND THE SOUTH SIDE OF THE SYSTEM NEAR WINNIPEG. SHOWERS TODAY WILL BE FOUND ON THE WEST SIDE OF THIS TROWAL...TO THE NW OF THE CENTER OF THE PV ANOMALY. THE RAP DOES NOT SHOW THIS DEFORMATION BAND OF PRECIP MOVING INTO WC MN UNTIL 15Z..THEN TRACKS IT NE ACROSS CENTRAL MN DURING THE DAY. KEPT POP MAGNITUDE RELATIVELY UNCHANGED AT 30-40 PERCENT ACROSS NRN PORTIONS OF THE MN CWA...JUST DELAYED ITS MOVEMENT INTO AND THROUGH CENTRAL MN TODAY. TONIGHT...HIGH PRESSURE CURRENTLY CENTERED FROM NW KANSAS BACK THROUGH MONTANA WILL DRIFT E AND SETTLE IN FROM CENTRAL ILLINOIS BACK INTO NODAK BY SUNDAY MORNING. AS THIS HIGH PRESSURE MOVES IN...IT WILL BRING WITH IT A SIGNIFICANT REDUCTION IN DEWPS...WHICH COULD FALL INTO THE 20S SOUTH OF THE MN RIVER THIS AFTERNOON...WITH 30S OVERSPREADING THE REST OF THE AREA TONIGHT. THIS DRY AIR WILL COMBINE WITH CLEAR SKIES AND A SLACKENING OF THE WINDS TO PROMOTE GOOD RADIATIONAL COOLING TONIGHT. JUST ABOUT EVERYONE SHOULD FIND THEMSELVES FALL INTO THE 30S BY SUNDAY MORNING...WITH A FEW SPOTS FROM SW MN UP THROUGH CENTRAL MN HAVING THE POTENTIAL TO PICK UP THEIR FIRST 32 OR COLDER LOW THIS SEASON. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 415 AM CDT SAT OCT 12 2013 SUNDAY WILL BE A NEAR PERFECT FALL DAY ACROSS THE REGION WITH HIGH PRESSURE OVERHEAD... LOTS OF SUNSHINE... LIGHT WINDS AND LOW AFTERNOON HUMIDITY. THE PLEASANT WEATHER WILL FADE ON MONDAY AS RAIN GRADUALLY OVERSPREADS THE REGION. THE NAM/GFS REMAIN THE FASTEST ON BRINGING A LOW PRESSURE SYSTEM FROM THE CENTRAL PLAINS TO MN BY TUESDAY MORNING WHILE THE ECMWF/GEM DON/T HAVE THE LOW REACHING INTO MN UNTIL TUESDAY NIGHT. CONTINUITY OVER THE PAST FOUR NIGHTS IS BEST WITH THE ECWMF. THIS SOLUTION RECEIVED THE MOST WEIGHTING WITH REGARDS TO PRECIPITATION TIMING AND RAIN AMOUNTS FROM MONDAY THROUGH TUESDAY. HENCE...LIGHT RAIN WILL LIKELY SPREAD INTO WESTERN MN MONDAY MORNING AND SHOULD BE NEARING I-35 BY EVENING. THE RAIN WILL GRADUALLY SPREAD ACROSS WESTERN WI MONDAY NIGHT WHILE INCREASING IN INTENSITY OVER WEST CENTRAL MN WHERE DEEP LAYER MOISTURE...STRONG FORCING AND LOW LEVEL MOISTURE TRANSPORT IS MAXIMIZED. RAINFALL AMOUNTS MONDAY NIGHT ACROSS THE FAR WESTERN CWA MAY REACH OR EXCEED AN INCH. THERE IS ALSO A THREAT FOR THUNDERSTORMS MONDAY NIGHT/EARLY TUESDAY ACROSS SOUTH CENTRAL MN WHERE THE NOSE OF A NEGATIVE LI AXIS EXISTS. RAIN WILL BE ONGOING ACROSS THE FA TUESDAY MORNING... BUT A DRY SLOT WILL LIKELY POKE INTO SOUTHERN MN DURING THE DAY. THIS WILL KNOCK THE INTENSITY OF THE RAIN DOWN. EXTENSIVE CLOUDINESS/LIGHT RAIN WILL LINGER FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT AS THE LOW PRESSURE SYSTEM ADVANCES SLOWLY FROM MN TO THE WESTERN GREAT LAKES. HIGH TEMPERATURES WILL BE QUITE COOL FROM TUESDAY THROUGH THURSDAY WITH READINGS IN THE UPPER 40S TO MIDDLE 50S. THE END OF THE WORK WEEK WILL STILL BE COOL ALONG WITH QUITE A BIT OF CLOUDINESS AS TROUGHING ALOFT INCREASES ACROSS THE CENTER OF THE COUNTRY. THE ECMWF BECOMES A BIT EXTREME WITH THE UPPER TROUGH... STRETCHING FROM HUDSON BAY TO BAJA BY THE WEEKEND. WITH TIME... THE ECMWF DEEPENS THE UPPER TROUGH IN THE CENTER OF THE COUNTRY WITH A LOW PRESSURE SYSTEM RIDING NORTHEAST FROM THE SOUTHERN PLAINS TO THE LOWER GREAT LAKES. THIS SOLUTION PRODUCES SNOW ACROSS IA AND SOUTHERN WI NEXT SUNDAY. THE GEFS WOULD SPLIT THE UPPER TROUGH WITH ONE PORTION OVER THE EASTERN CONUS AND A CUT- OFF DEVELOPING IN THE SOUTHWEST. ON A SIDE NOTE...WE LEARNED FROM LAST WINTER THAT THESE TYPES OF SYSTEMS ON THE ECMWF TRENDED NORTHWARD WITH TIME. THE 7 TO 10 DAY PERIOD COULD BE INTERESTING. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1224 AM CDT SAT OCT 12 2013 COLD FRONT JUST NOW MOVING INTO WI. SHRA/TSRA AHEAD OF THE BOUNDARY HAS REALLY FALLEN APART...SO PARED BACK PRECIP MENTION AT EAU TO A VCSH. MVFR/VFR STRATUS HAS MOVED INTO WRN MN BEHIND THE BOUNDARY...BUT LEADING EDGE OF STRATUS IS MOVING NNE TOWARD LAKE SUPERIOR AND MAY CLIP MSP AT BEST. NAM AND RAP SHOW THESE CLOUDS MORE OR LESS REMAINING STATIONARY UNTIL AFTER 12Z AS NEXT SHORT WAVE COMES OUT OF THE DAKOTAS AND INTO MN. CONFIDENCE IS HIGH IN MVFR CIGS RESULTING FOR MUCH OF THE DAY ACROSS CENTRAL MN...BUT IS A FAIR AMOUNT OF UNCERTAINTY WITH HOW LOW CIGS WILL BE DOWN TOWARD THE TWIN CITIES. AT THE VERY LEAST CU RULE OFF THE NAM/RAP WOULD SAY MIXING AND CAA WILL COMBINE BRING BKN CIGS ABOUT AS FAR SOUTH AS MKT THIS AFTERNOON. ANY ADDITIONAL PRECIP WILL BE MOVING INTO WRN MN AFTER 14Z AND WILL MAINLY IMPACT CENTRAL MN...SO HAVE VCSH MENTIONS AT AXN/STC. WINDS WILL REMAIN GUSTY ACROSS WRN MN THROUGH THE NIGHT...BUT WILL RELAX SOME ACROSS ERN MN/WRN WI. GUSTY WSW WINDS RETURN FOR SUNDAY...THOUGH NOT AS STRONG AS WAS SEEN SATURDAY. SUNDAY NIGHT...HIGH PRESSURE WILL BEGIN MOVING IN WHICH WILL FINALLY START TO RELAX THE WINDS AND CLEAR OUT THE SKIES. KMSP...THE FIELD MAY GET CLIPPED BY A BATCH OF MVFR CIGS BETWEEN 8 AND 10Z...BUT LOOKS MORE LIKELY THAT MVFR CIGS WEST OF MSP WILL HEAD MORE FOR THE NORTH METRO. MAIN CLOUD MASS WILL MOVE IN LATE SUNDAY MORNING. FOR NOW KEPT THIS VFR...THOUGH SOME CIGS DOWN TO AROUND 025 MAY BE POSSIBLE. ANY SHOWERY ACTIVITY TODAY WILL REMAIN WELL NORTH OF MSP. /OUTLOOK FOR KMSP/ MON...VFR DURING DAY. MVFR/IFR WITH SHRA OVERNIGHT. WINDS E 10 KTS. TUE...MVFR/IFR WITH SHRA. WINDS NNE 7-12 KTS. WED...CHANCE MVFR/SHRA IN MORNING. WINDS NW 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...MPG LONG TERM...RAH AVIATION...MPG
AREA FORECAST DISCUSSION...CORRECTED
NWS DULUTH MN
319 AM CDT SAT OCT 12 2013 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 318 AM CDT SAT OCT 12 2013 VERTICALLY STACKED SYSTEM IS LIFTING NWD INTO SOUTH CENTRAL CANADA AT 08Z. SEVERAL FRONTAL BOUNDARIES FROM THIS SYSTEM WILL AFFECT THE FA THROUGH THE DAY AND INTO THIS EVENING. AS THESE FRONTS PROGRESS THROUGH THE AREA...SEVERAL PIECES OF SHORT WAVE ENERGY WILL ROTATE OVERHEAD AND GENERATE SOME SHOWERS. BEST OPPORTUNITY FOR RAIN WILL BE THIS AFTERNOON OVER THE WESTERN TWO THIRDS OF THE FA. RAIN FALL AMOUNTS WILL BE ON THE LIGHT SIDE EXCEPT OVER THE BORDERLAND WHERE UP TO .20 INCHES MAY FALL. SOME BREAKS IN THE CLOUD COVER ARE POSSIBLE...ESPECIALLY OVER NW WI WHICH WILL ALLOW MAX TEMPS TO REACH INTO THE UPPER 50S TO AROUND 60...WITH LOWER TO MIDDLE 50S ELSEWHERE. A NEGATIVELY TILTED SHORT WAVE TROF WILL SWEEP THROUGH THE FA TONIGHT. THE SHOWERS WILL LINGER INTO THE EVENING OVER THE NORTHERN PORTION OF THE FA UNDERNEATH BEST FORCING FROM SAID TROF. THE SHOWERS WILL DIMINISH OVERNIGHT. A DRY DAY IS IN STORE FOR MONDAY AS HIGH PRESSURE SETTLES OVER THE UPPER MIDWEST. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 318 AM CDT SAT OCT 12 2013 WEAK HIGH PRESSURE WILL BE IN PLACE ACROSS THE WRN GREAT LAKES SUN NIGHT AND EARLY MONDAY...BUT WILL QUICKLY SHIFT TO THE EAST AS A DEEP TROUGH OVER THE ROCKIES EJECTS EWD INTO THE PLAINS AND MIDWEST THROUGH WEDNESDAY. THIS SYSTEM WILL BRING A PROLONGED PERIOD OF RAIN TO THE NORTHLAND...ALONG WITH COOLER TEMPERATURES. THERE ARE SIGNIFICANT DIFFERENCES IN THE TRACK OF THIS LOW PRESSURE SYSTEM THROUGH THE CENTRAL US. THE LATEST RUNS OF THE ECMWF AND GEM ARE MUCH SLOWER THAN THE GFS AND NAM. THE DETERMINISTIC RUN OF THE GFS IS EVEN FASTER THAN THE GFS ENSEMBLE MEAN. SO...WILL LEAN MORE TOWARD A SLOWER PROGRESSION OF THE RAIN THROUGH THE REGION INTO THE MIDDLE OF THE WEEK. EVEN AS THIS TROUGH LIFTS EWD INTO NEW ENGLAND AND ERN CANADA LATE WED AND THURSDAY...A SECONDARY RE-ENFORCING UPPER TROUGH DROPS INTO THE UPPER MIDWEST QUICKLY ON THE HEALS OF THE DEPARTING LOW THROUGH FRIDAY...WITH ADDITIONAL CHANCES FOR SHOWERS. THE BEST CHANCE FOR SIGNIFICANT RAINFALL THIS WEEK APPEARS TO BE MON NIGHT AND TUESDAY. HIGH TEMPERATURES THROUGH THE WEEK WILL BE STEADY...IN THE 40S AND LOWER 50S. WHILE OVER NIGHT LOWS WILL OCCASIONALLY DIP INTO THE LOWER TO MID 30S...WITH WIDESPREAD UPPER 30S AND 40S THROUGH THE WEEK. WOULD NOT BE SURPRISED TO SEE A FEW FLAKES MIXED IN ACROSS THE NRN COUNTIES LATE IN THE WEEK. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1200 AM CDT SAT OCT 12 2013 MVFR CEILINGS WERE MOVING THROUGH THE AREA WITH VERTICALLY STACKED LOW. THE RAP 900-925MB CONDENSATION PRESSURE DEFICITS WERE DOING A DECENT JOB WITH THESE LOWER CEILINGS AND WAS USED TO IN THE TAFS. THE MVFR CEILINGS MAY NOT REACH KHYR OR ONLY BE INTERMITTENT THERE. AN UPPER LEVEL TROUGH AND COLD AIR ALOFT WILL LEAD TO PLENTY OF CU/STRATOCU BY SATURDAY AFTERNOON...WITH WIDESPREAD LOW VFR/MVFR CEILINGS AND SOME SHOWERS. SHOWERS WILL BE MOST WIDESPREAD OVER NORTHEAST MINNESOTA. && .PRELIMINARY POINT TEMPS/POPS... DLH 54 39 55 39 / 20 10 0 0 INL 54 34 52 33 / 50 50 0 0 BRD 53 36 57 39 / 20 0 0 10 HYR 60 36 58 30 / 10 0 0 0 ASX 60 38 57 33 / 10 0 0 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 10 AM CDT SUNDAY FOR LSZ121-140>148. && $$ SHORT TERM...GSF LONG TERM...BJT AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1243 AM CDT SAT OCT 12 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 310 PM CDT FRI OCT 11 2013 LEADING LINE OF CONVECTION WILL CONTINUE TO MOVE SLOWLY EAST INTO WESTERN WISCONSIN THIS EVENING BEFORE DIMINISHING. INDIVIDUAL CELLS WITH IN THE LINE WERE MOVING NORTHEAST CLOSE TO 60 KTS DURING THE AFTERNOON. STILL HAD STABLE BOUNDARY LAYER INTO THE AFTERNOON WHICH HELD SURFACE WIND GUSTS IN CHECK. THE UPPER CIRCULATION LIFTING NORTH/NORTHEAST INTO SOUTHERN NORTH DAKOTA LATE THIS AFTERNOON. THERE REMAINS A NARROW CORRIDOR OF INSTABILITY TO THE WEST OF THE LINE AND VARIOUS HIRES MODELS CONTINUE TO INDICATE ANOTHER BROKEN LINE OF CONVECTION EXPECTED TO DEVELOP AND LIFT NORTHEAST INTO EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA INTO THIS EVENING. STILL MAY CLIP THE NORTHWEST QUADRANT OF THE CWA INTO THIS EARLY EVENING. STRONG SOUTHEAST TO SOUTH WINDS EXPECTED TO CONTINUE AHEAD OF THE FEATURE GRADUALLY DIMINISHING OVERNIGHT. WILL LEAVE THE WIND ADVISORY GO UNTIL EXPIRATION. COLDER AIR TO WRAP IN BEHIND THE SYSTEM OVERNIGHT...WITH LOWER CLOUDS EXPECTED TO WRAP INTO NORTHERN PORTION OF THE REGION INTO THE DAY SATURDAY. SOME LIGHT SHOWERS ALSO WILL AFFECT THE NORTHERN AREA AS WELL AS THE UPPER LOW EXITS THE REGION TO THE NORTHEAST. SURFACE WINDS WILL INCREASE AGAIN SATURDAY MORNING WITH SOME GUSTS TO 30 KNOTS AGAIN FROM THE SOUTHWEST AND WEST. HIGH TEMPERATURES ARE EXPECTED TO COOL BACK CLOSE TO AVERAGE FOR THIS TIME OF YEAR. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 310 PM CDT FRI OCT 11 2013 SURFACE HIGH PRESSURE BUILDS IN FOR SATURDAY NIGHT AND SUNDAY...AND BRINGS A BRIEF PERIOD OF MOSTLY CLEAR SKIES AND LIGHT WINDS. TEMPERATURES WILL COOL INTO THE MID AND UPPER 30S BY EARLY SUNDAY MORNING...WITH PATCHY FROST EXPECTED /MAINLY ACROSS CENTRAL MN AND WI/. SUNDAY WILL FEATURE NEAR NORMAL TEMPERATURES IN THE UPPER 50S AND LOWER 60S...ALONG WITH MOSTLY SUNNY SKIES. MONDAY THROUGH A LARGE PORTION OF NEXT WEEK WILL BE FOCUSED ON THE EVOLUTION OF A WESTERN CONUS UPPER TROUGH...WHICH IS FORECAST TO CLOSE OFF OVER THE ROCKIES AND THEN SLOWLY MEANDER ACROSS THE CENTRAL CONUS TOWARD THE UPPER GREAT LAKES. THE 15.12Z MODEL SOLUTIONS CONTINUED TO FEATURE THE TIMING DIFFERENCES THAT HAVE BEEN PRESENT IN PRIOR RUNS. NAMELY...THE ECMWF IS DEEPER AND SLOWER THAN THE GFS WITH THE LOW. THE RESULT IS ABOUT A 12 HOUR DIFFERENCE BETWEEN THE TWO WITH RESPECT TO PRECIP ONSET/DEPARTURE. DESPITE THE TIMING DIFFERENCES...CONFIDENCE IS HIGH THAT PRECIP WILL ENTER WEST CENTRAL MN BY MONDAY AFTERNOON...AND THEN EXPAND ACROSS THE AREA ON MONDAY NIGHT INTO TUESDAY. HAVE INCLUDED 80-90 POPS ACROSS THE MN PORTION OF THE FORECAST AREA...AND 60-70 POPS ACROSS WEST CENTRAL WI. BOTH MODELS FEATURE RUN TOTAL PRECIPITATION AMOUNTS FROM 1 TO OVER 3 INCHES ACROSS THE FORECAST AREA BY 12Z FRIDAY. A LARGE TROUGH IS CARVED OUT ACROSS MUCH OF CANADA AND THE CENTRAL/EASTERN UNITED STATES INTO NEXT WEEKEND. THE ASSOCIATED REDUCED HEIGHTS...IN COMBINATION WITH ENHANCED CLOUDINESS AND PRECIPITATION...WILL CAUSE HIGH TEMPERATURES TO RUN AROUND 5 TO 10 DEGREES BELOW CLIMATOLOGICAL NORMALS...WITH HIGHS GENERALLY IN THE UPPER 40S AND LOWER 50S FROM TUESDAY THROUGH FRIDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1224 AM CDT SAT OCT 12 2013 COLD FRONT JUST NOW MOVING INTO WI. SHRA/TSRA AHEAD OF THE BOUNDARY HAS REALLY FALLEN APART...SO PARED BACK PRECIP MENTION AT EAU TO A VCSH. MVFR/VFR STRATUS HAS MOVED INTO WRN MN BEHIND THE BOUNDARY...BUT LEADING EDGE OF STRATUS IS MOVING NNE TOWARD LAKE SUPERIOR AND MAY CLIP MSP AT BEST. NAM AND RAP SHOW THESE CLOUDS MORE OR LESS REMAINING STATIONARY UNTIL AFTER 12Z AS NEXT SHORT WAVE COMES OUT OF THE DAKOTAS AND INTO MN. CONFIDENCE IS HIGH IN MVFR CIGS RESULTING FOR MUCH OF THE DAY ACROSS CENTRAL MN...BUT IS A FAIR AMOUNT OF UNCERTAINTY WITH HOW LOW CIGS WILL BE DOWN TOWARD THE TWIN CITIES. AT THE VERY LEAST CU RULE OFF THE NAM/RAP WOULD SAY MIXING AND CAA WILL COMBINE BRING BKN CIGS ABOUT AS FAR SOUTH AS MKT THIS AFTERNOON. ANY ADDITIONAL PRECIP WILL BE MOVING INTO WRN MN AFTER 14Z AND WILL MAINLY IMPACT CENTRAL MN...SO HAVE VCSH MENTIONS AT AXN/STC. WINDS WILL REMAIN GUSTY ACROSS WRN MN THROUGH THE NIGHT...BUT WILL RELAX SOME ACROSS ERN MN/WRN WI. GUSTY WSW WINDS RETURN FOR SUNDAY...THOUGH NOT AS STRONG AS WAS SEEN SATURDAY. SUNDAY NIGHT...HIGH PRESSURE WILL BEGIN MOVING IN WHICH WILL FINALLY START TO RELAX THE WINDS AND CLEAR OUT THE SKIES. KMSP...THE FIELD MAY GET CLIPPED BY A BATCH OF MVFR CIGS BETWEEN 8 AND 10Z...BUT LOOKS MORE LIKELY THAT MVFR CIGS WEST OF MSP WILL HEAD MORE FOR THE NORTH METRO. MAIN CLOUD MASS WILL MOVE IN LATE SUNDAY MORNING. FOR NOW KEPT THIS VFR...THOUGH SOME CIGS DOWN TO AROUND 025 MAY BE POSSIBLE. ANY SHOWERY ACTIVITY TODAY WILL REMAIN WELL NORTH OF MSP. /OUTLOOK FOR KMSP/ MON...VFR DURING DAY. MVFR/IFR WITH SHRA OVERNIGHT. WINDS E 10 KTS. TUE...MVFR/IFR WITH SHRA. WINDS NNE 7-12 KTS. WED...CHANCE MVFR/SHRA IN MORNING. WINDS NW 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...DWE LONG TERM...LS AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
1200 AM CDT SAT OCT 12 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 301 PM CDT FRI OCT 11 2013 AT 300PM/2000Z...THERE WAS A STRONG AND STACKED LOW PRESSURE SYSTEM LIFTING NNE THROUGH NORTH CENTRAL SOUTH DAKOTA. A STRONG COLD FRONT STRETCHED FROM THE LOW THROUGH CENTRAL SOUTH DAKOTA...CENTRAL NEBRASKA...AND CENTRAL KANSAS. THIS STORM SYSTEM HAD MULTIPLE BANDS OF SHOWERS AND STORMS ACROSS THE DAKOTAS...WESTERN MINNESOTA...AND SOUTHERN MANITOBA. ONE BAND OF SHOWERS AND STORMS STRETCHED FROM NE NORTH DAKOTA THROUGH NW AND WESTERN MINNESOTA. THE BAND WAS STEADILY MOVING NORTH AND SLOWLY EAST. CLOUDY TO MOSTLY CLOUDY SKIES COVERED MUCH OF THE DAKOTAS AND WESTERN AND SOUTHERN MINNESOTA...WHILE EASTERN MINNESOTA AND WISCONSIN STILL HAD PARTLY TO MOSTLY SUNNY SKIES. THE NORTHLAND HAD SE WINDS OF ABOUT 10 TO 20 MPH WITH GUSTS UP TO 35 MPH IN SOME AREAS. TEMPERATURES WERE IN THE LOWER 70S ACROSS MOST OF THE REGION...EXCEPT FOR 60S OVER THE ARROWHEAD AND UPPER 70S NEAR BAYFIELD PENINSULA. DEW POINT TEMPERATURES WERE IN THE UPPER 40S TO LOWER 50S. TONIGHT...THE STRONG LOW PRESSURE SYSTEM WILL LIFT THROUGH EASTERN NORTH DAKOTA THIS EVENING AND SOUTHERN MANITOBA LATE TONIGHT. THE STRONG COLD FRONT WILL MOVE THROUGH THE NORTHLAND OVERNIGHT. THE BAND OF SHOWERS AND STORMS CURRENTLY ACROSS WESTERN MINNESOTA WILL WORK ITS WAY THROUGH AT LEAST THE WESTERN FORECAST AREA LATE THIS AFTERNOON AND THIS EVENING BEFORE BEGINNING TO DISSIPATE. ANOTHER BAND OF SHOWERS AND STORMS WILL LIKELY FOLLOW IN ITS WAKE A FEW HOURS BEHIND THE FIRST BAND. I FORECAST HIGH CHANCES OF PCPN FOR THE SW FORECAST AREA SINCE IT WILL LIKELY BE AFFECTED...AND WE MAY NEED TO INCREASE PCPN CHANCES OVER OTHER PARTS OF THE FORECAST AREA AS THE BAND OF SHOWERS AND STORMS BEGINS TO MOVE INTO THE NORTHERN AND CENTRAL FORECAST AREA. THESE SHOWERS AND STORMS COULD PRODUCE VERY GUSTY WINDS...PERHAPS AS HIGH AS 45 MPH...DUE TO THE STRONG FLOW ALOFT IN THE MIXING LAYER AND JUST ABOVE THE MIXING LAYER. AND DESPITE THE DECOUPLING THAT WILL OCCUR THIS EVENING...THE SHOWERS COULD STILL MIX DOWN THESE STRONG GUSTS FOR A WHILE THIS EVENING. STORM PREDICTION CENTER CONTINUES TO HAVE A SLIGHT RISK OF SEVERE STORMS ACROSS THE FAR SW FORECAST AREA. THIS IS DUE TO THE STRONG LOW LEVEL SHEAR AND STRONG LOW LEVEL FLOW WHICH COULD PRODUCE DAMAGING WINDS AND ISOLATED TORNADOES WITH STORMS...BUT THE LIMITING FACTOR IS CAPE...ESPECIALLY SURFACE BASED CAPE. OVERNIGHT LOWS SHOULD BE IN THE UPPER 40S TO MID 50S. SATURDAY...THE NORTHLAND WILL HAVE A CLOUDY AND WINDY DAY IN THE WAKE OF THE COLD FRONT AS A POTENT SHORTWAVE LIFTS THROUGH THE NORTHLAND AND SURROUNDING REGION. THE SW WINDS OF 15 TO 20 MPH WILL GUST UP TO 30 MPH. THE COLD AIR ALOFT AND STRONG MIXING WILL HELP GENERATE THICK CLOUD COVER AND RAIN SHOWERS. I LOWERED THE HIGH TEMPERATURES TO THE LOW 50S ACROSS NE MINNESOTA AND THE UPPER 50S TO NEAR 60 DEGREES ACROSS NW WISCONSIN. WE MAY NEED TO LOWER THE TEMPERATURES A BIT MORE DEPENDING ON HOW QUICKLY THE HEAVY CLOUD COVER DEVELOPS AND/OR MOVES INTO THE NORTHLAND. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 301 PM CDT FRI OCT 11 2013 AN UPPER LEVEL TROUGH WILL SWING ACROSS THE NORTHLAND SATURDAY NIGHT...RESULTING IN SOME EVENING SHOWERS ACROSS THE REGION. THE GUSTY SOUTHWEST TO WEST WINDS WILL ALSO CONTINUE INTO THE NIGHT BEFORE SUBSIDING SOME OVERNIGHT. SKIES WILL GRADUALLY START TO CLEAR LATER IN THE NIGHT FROM WEST TO EAST. THE NEXT SYSTEM WILL ALREADY START TO AFFECT THE REGION LATER SUNDAY...AS HIGH AND MID CLOUDS INCREASE ACROSS AT LEAST THE SW PART OF THE REGION. THE MODELS INDICATE SOME PRECIPITATION MAY MAKE IT INTO THE CWA LATER SUNDAY NIGHT...ESPECIALLY IN THE BRAINERD LAKES REGION. BEYOND THAT...IT IS SHAPING UP TO BE A VERY WET PERIOD MONDAY INTO WEDNESDAY. THERE ARE SOME DIFFERENCES AMONGST THE DETERMINISTIC MODELS...ESPECIALLY WITH RESPECT TO TIMING AND SPEED OF THE SYSTEM...BUT OVERALL IT LOOKS LIKE IT WILL BE A WET EARLY TO MIDDLE PART OF THE UPCOMING WORK WEEK. TEMPERATURES WILL BE KEPT COOLER BY THE RAIN AND CLOUDS. THE GFS AND ECMWF DISAGREE TO SOME EXTENT DURING THE LATTER PART OF THE WORK WEEK AS WELL...BUT BOTH MODELS MAINTAIN SOME SORT OF UNSETTLED WEATHER WITH SOME SCATTERED SHOWERS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1200 AM CDT SAT OCT 12 2013 A FRONTAL BOUNDARY WAS MOVING THROUGH THE NORTHLAND LATE THIS EVENING...WITH A BAND OF SHOWERS AND THUNDERSTORMS EXTENDING FROM KINL TO K04W AT 0430Z. THIS BAND WAS MOVING NORTHEAST. THE NMM-WRF WAS DOING A GOOD JOB DEPICTING THIS BAND OF RAIN...AND FORECASTS IT TO DIMINISH IN INTENSITY/COVERAGE AROUND 08Z. MVFR CEILINGS WERE MOVING TOWARD KBRD BEHIND THIS FRONT AND SHOULD PROGRESS NORTH AND EAST OVERNIGHT. THE RAP 900-925MB CONDENSATION PRESSURE DEFICITS WERE DOING A DECENT JOB WITH THESE LOWER CEILINGS AND WAS USED TO IN THE TAFS. THE MVFR CEILINGS MAY NOT REACH KHYR OR ONLY BE INTERMITTENT THERE. AN UPPER LEVEL TROUGH AND COLD AIR ALOFT WILL LEAD TO PLENTY OF CU/STRATOCU BY SATURDAY AFTERNOON...WITH WIDESPREAD LOW VFR/MVFR CEILINGS AND SOME SHOWERS. SHOWERS WILL BE MOST WIDESPREAD OVER NORTHEAST MINNESOTA. && .PRELIMINARY POINT TEMPS/POPS... DLH 50 54 38 54 / 60 50 10 0 INL 52 53 35 52 / 50 60 30 10 BRD 48 54 36 57 / 60 50 10 0 HYR 53 61 36 58 / 40 10 10 0 ASX 55 61 39 57 / 40 10 10 0 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. LS...SMALL CRAFT ADVISORY UNTIL 9 AM CDT SUNDAY FOR LSZ140-141. && $$ SHORT TERM...GROCHOCINSKI LONG TERM...DAP AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1114 PM CDT Fri Oct 11 2013 .UPDATE: Issued at 929 PM CDT Fri Oct 11 2013 Scattered showers and thunderstorms currently extending from northwest Missouri through southeast Kansas is in response to upstream upper air pertubation over eastern Colorado southwest Kansas moving east-northweastward into northern and central Kansas. Cold frontal boundary extending from western Iowa through northeast Kansas then south-central Kansas continues too move east and southeastward. We delayed the arrival of showers and thunderstorms over most areas in the LSX CWA. Believe shower and thunderstorm activitly will be moving into Qunicy - Columbia area after 0700 UTC and into St. Louis area after 10 or 11 UTC. Would not be surprise if a new band of convection forms after midhight ahead of the current bands observed on EAX and SGF radars. RAP and local LSX WRF models supporting this tread. Instability not too impressive at this time over area. Well defined subsidence inversion at 780 mb noted at SGF sounding this evening. This might challenge convection a little. However colder air aloft over western Kansas may increase the instability early Saturday morning. Adjusted temps a little over CWA. Przybylinski && .SHORT TERM: (Through Late Tonight) Issued at 318 PM CDT Fri Oct 11 2013 Although upstream front/dry line remain tranquil at 20z, believe that modest instability and convergence along the front should initiate scattered convection over the next few hours. The coverage of this activity should then increase later tonight as upstream shortwave currently near the 4 corners works into the region. It may take a while for the upstream convection to work into the CWA, but amount of moisture, instability, and lift all suggest scattered convection will threaten much of the CWA late tonight and during the predawn hours. For now have placed the highest PoPs at 50% west of a KFAM-KTAZ line, with PoPs tapering off southeast of this line to low chance in KSLO area by daybreak. For now have stayed with overnight lows in the 50s with the thinking that there should be a bit of cooling due to precip; however if convection does remain isolated these lows will likely be too cool by a cat or so. Truett .LONG TERM: (Saturday through Next Friday) Issued at 318 PM CDT Fri Oct 11 2013 Overall forecast trends appear on track for tomorrow with scattered showers and thunderstorms expected to persist from tonight into Saturday. A stacked low pressure system over the northern Plains will lift into Canada by tomorrow morning while at least one secondary vort max rotates around its back side, providing another source of lift for MO/IL. The occluding system will also continue to draw a narrow ribbon of moisture through the area ahead of the cold front (PW values will be near +2 SD). In addition, models are forecasting a coupled jet structure at H3 which places the LSX CWA beneath the favored region for enhanced lift, especially between 12-18z. The combination of these factors should be sufficient for isolated to scattered precipitation, but this does not look like a widespread rainfall event because of the spatially limited moisture and overall weak forcing. Precipitation should end fairly quickly after the cold front moves through the region due to increasing subsidence with a 1025 hPa high pressure center that will be sliding into the northern Plains and western Great Lakes on Saturday night and Sunday. This area of high pressure will push the cold front to near the MO/AR border before cyclogenesis over the central Plains occurs and lifts the stalled boundary back northward as a warm front on Tuesday. There are still some model differences regarding the upper level disturbance which will be responsible for the surface low, but recent runs of the ECMWF/GFS/GEM all agree at that least a portion of that energy will lift through the central CONUS on Monday night and Tuesday. The moisture and dynamics are expected to be much better with the Mon/Tue system. Depending on how the upper level disturbance splits apart, the other half could move across the area during the middle or end of the week and provide additional precipitation chances. Kanofsky && .AVIATION: (For the 06z TAFs through 06z Saturday Night) Issued at 1053 PM CDT Fri Oct 11 2013 Cold front extending from a sfc low over nern ND south through nwrn MO and sern KS will move sewd through UIN and COU late tgt, and through the St Louis metro area Saturday mrng. Scattered showers and thunderstorms are along and just ahead of this front this evng. A band of VFR, low-mid level clouds well ahead of the front in COU and UIN this evng will advect into the St Louis metro area late tgt. Showers and a few storms should move through UIN and COU late tgt, and through the St Louis metro area around 12z Saturday. The s-sely sfc wind will veer around to a nwly direction after fropa in UIN and COU by early Saturday mrng and in the St Louis metro area by late mrng. The low level clouds will clear out in the mrng in UIN and COU, and in the aftn in the St Louis metro area as a ridge of high pressure builds into the area behind the cold front. Specifics for KSTL: Clouds at 5000-7000 ft will advect into STL just after 06z Saturday with scattered showers moving into the STL area by 12z Saturday. The showers will move out by late mrng with the clouds clearing out in the aftn. Sely sfc wind will veer around to a swly direction Saturday mrng, and a nwly direction Saturday aftn. GKS && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
928 AM CDT SAT OCT 12 2013 .UPDATE... UPDATED TO INCREASE PRECIPITATION CHANCES FOR EARLY AFTERNOON. && .DISCUSSION... LINE OF CONVECTION CONTINUES TO HOLD TOGETHER AS IT BEGINS TO MOVE INTO EASTERN ARKANSAS THIS MORNING. THIS LINE SHOULD MAKE IT TO THE MISSISSIPPI RIVER JUST BEFORE NOON...SO HAVE INCREASED RAIN CHANCES IN THIS CORRIDOR FROM ROUGHLY 12-3 PM. HAVE ALSO INCREASED THE SHOWER INTENSITY TO MODERATE BASED ON REFELCTIVITY TRENDS AND CURRENT RAINFALL AMOUNTS. STORMS HAVE BEEN PRODUCING GUSTS IN THE 20 TO 30 MPH RANGE...BUT WITH A FEW MORE HOURS OF HEATING THEY COULD INTENSIFY TO PRODUCE GUSTS NEAR 40 MPH. ALL OTHER FORECAST PARAMETERS ARE CURRENTLY ON TRACK. JAB && .PREV DISCUSSION... /ISSUED 617 AM CDT SAT OCT 12 2013/ DISCUSSION... /ISSUED 501 AM CDT SAT OCT 12 2013/ A RATHER ACTIVE PATTERN OVER THE NEXT SEVEN DAYS. ABOVE NORMAL TEMPS WILL CONTINUE TODAY... BUT WILL LIKELY BE TEMPERED A BIT BY INCREASED CLOUDS AHEAD OF SHORTWAVE LIFTING INTO THE MID MS RIVER VALLEY. THIS FEATURE HAD AIDED THUNDERSTORM DEVELOPMENT OVER EASTERN OK EARLY THIS MORNING. CONVECTIVE POTENTIAL WILL SPREAD INTO EASTER AR LATE THIS MORNING/EARLY AFTERNOON...WITH THE SHORTWAVE PASSING BY TO THE NORTH. NAM BUFR SOUNDINGS FOR JONESBORO DEPICTED SURFACE BASED CAPE AROUND 1500 J/KG AT 19Z... ACCOMPANIED BY MODEST SHEAR. A FEW STORMS MAY CROSS THE RIVER INTO WEST TN... BUT SHOULD WEAKEN AS THEY MOVE FURTHER INTO THE MIDLEVEL RIDGE. BY THIS EVENING... THE SHORTWAVE WILL HAVE MOVED WELL OFF THE NORTHEAST AND THE BOUNDARY LAYER WILL HAVE STABILIZED. A SURFACE COLD FRONT WILL DROP INTO THE MIDSOUTH AND STALL TONIGHT BEHIND THE EXITING MIDLEVEL SHORTWAVE. SLIGHTLY DRIER AIR AND SHORTWAVE RIDGING SHOULD KEEP RAIN CHANCES AT BAY FOR SUNDAY. BY MONDAY AFTERNOON... THE FIRST IN A SERIES OF SHORTWAVES WILL EJECT FROM A DEEP UPPER TROF CENTERED OVER CENTRAL ROCKIES. THIS SHORTWAVE WILL ARRIVE OVER THE OZARKS MONDAY EVENING AS IT DEAMPLIFIES. LOW LEVEL FLOW WILL VEER IN RESPONSE TO THE APPROACHING UPPER LEVEL WAVE LATE MONDAY/EARLY TUESDAY...RETURNING MODIFIED GULF AIR THE MIDSOUTH. GFS PROGS PRECIPITABLE WATER VALUES NEAR 1.9 INCHES BY TUESDAY AFTERNOON. GFS AND ECMWF MODELS LIFT THE CENTER OF THE DEEP AND BROAD LONGWAVE TROF FROM THE ROCKIES INTO THE CENTRAL PLAINS BY WEDNESDAY... LOWERING HEIGHTS OVER MUCH OF CONUS. A SURFACE COLD FRONT WILL LAY OUT NEARLY PARALLEL TO THE SOUTHWEST FLOW ALOFT...BEFORE DROPPING THROUGH THE MIDSOUTH WITH A SHORTWAVE TROF PASSAGE LATE WEDNESDAY. GIVEN THE PREFRONTAL MOISTURE PLUME AND COLD FRONTAL PASSAGE... RAIN CHANCES APPEAR GOOD TUESDAY AND WEDNESDAY. BY LATE WEDNESDAY... THE GFS AND ECMWF BEGIN TO PART WAYS. THE GFS KEEPS A RIDGE WEST/TROF EAST PATTERN THROUGH THE WEEKEND...KEEPING THE MIDSOUTH IN DRY NORTHWEST FLOW ALONG. CONVERSELY...THE ECMWF DROPS SIGNIFICANT UPPER LEVEL ENERGY FROM WESTERN CANADA INTO THE THE FOUR CORNERS REGION BY FRIDAY...THEN EJECTS AN OPEN BUT HIGHLY AMPLIFIED TROF INTO THE CENTRAL AND SOUTHERN PLAINS BY LATE SATURDAY. THE ECMWF SOLUTION WOULD RESULT IN POTENTIALLY ACTIVE WEATHER ACROSS THE MIDSOUTH ON SATURDAY...A VERY DIFFERENT SOLUTION THAN THAT OF THE GFS. EXTENDED FORECAST PERIODS WERE HEAVILY WEIGHTED TOWARD THE ECMWF... GIVEN THE ECMWF/S GREATER RECENT RUN TO RUN CONSISTENCY. WITH THE LACK OF GFS CONCURRENCE...FORECAST CONFIDENCE IS BELOW AVERAGE FOR THE LATE WEEK PERIODS. PWB && .AVIATION... 12Z TAF SET PATCHY FOG IS OCCURRING AGAIN THIS MORNING AT KMKL REDUCING VSBYS TO MVFR OR IFR AT TIMES. FOG WILL LIFT AFTER 13Z. SCT TSRAS WILL DEVELOP TODAY ACROSS THE CWA AHEAD OF AN APPROACHING COLD FRONT. WILL CONTINUE MENTION OF VCTS FOR NOW. EXPECT GENERALLY VFR CONDITIONS UNLESS A TAF SITE IS AFFECTED BY A TSRA. AFTER 01Z...EXPECT TSRAS TO DIE OUT. NOT SURE ABOUT CLOUD COVER DURING THE EVENING INTO THE OVERNIGHT HOURS. RAP INDICATES THERE COULD BE SOME LOWER CIGS OCCUR DURING AT LEAST THE EVENING HOURS AND CURRENTLY ON SATELLITE THERE IS SOME LOWER CIGS IN OKLAHOMA ALONG FRONT. OTHER MODELS SCATTER CLOUDS OUT. FOR NOW WILL CONTINUE WITH VFR CONDITIONS BUT WILL CHANGE FROM SCT040 SCT120 TO BKN040. CAN/T RULE OUT SOME PATCHY FOG AT KMKL AGAIN LATE TONIGHT. LIGHT S WINDS WILL BECOME NE THIS EVENING. KRM && .PRELIMINARY POINT TEMPS/POPS... MEM 81 60 80 59 / 60 10 10 10 MKL 79 57 80 54 / 30 20 0 0 JBR 77 57 77 54 / 70 10 10 10 TUP 83 60 80 59 / 20 10 0 0 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
617 AM CDT SAT OCT 12 2013 .DISCUSSION... /ISSUED 501 AM CDT SAT OCT 12 2013/ A RATHER ACTIVE PATTERN OVER THE NEXT SEVEN DAYS. ABOVE NORMAL TEMPS WILL CONTINUE TODAY... BUT WILL LIKELY BE TEMPERED A BIT BY INCREASED CLOUDS AHEAD OF SHORTWAVE LIFTING INTO THE MID MS RIVER VALLEY. THIS FEATURE HAD AIDED THUNDERSTORM DEVELOPMENT OVER EASTERN OK EARLY THIS MORNING. CONVECTIVE POTENTIAL WILL SPREAD INTO EASTER AR LATE THIS MORNING/EARLY AFTERNOON...WITH THE SHORTWAVE PASSING BY TO THE NORTH. NAM BUFR SOUNDINGS FOR JONESBORO DEPICTED SURFACE BASED CAPE AROUND 1500 J/KG AT 19Z... ACCOMPANIED BY MODEST SHEAR. A FEW STORMS MAY CROSS THE RIVER INTO WEST TN... BUT SHOULD WEAKEN AS THEY MOVE FURTHER INTO THE MIDLEVEL RIDGE. BY THIS EVENING... THE SHORTWAVE WILL HAVE MOVED WELL OFF THE NORTHEAST AND THE BOUNDARY LAYER WILL HAVE STABILIZED. A SURFACE COLD FRONT WILL DROP INTO THE MIDSOUTH AND STALL TONIGHT BEHIND THE EXITING MIDLEVEL SHORTWAVE. SLIGHTLY DRIER AIR AND SHORTWAVE RIDGING SHOULD KEEP RAIN CHANCES AT BAY FOR SUNDAY. BY MONDAY AFTERNOON... THE FIRST IN A SERIES OF SHORTWAVES WILL EJECT FROM A DEEP UPPER TROF CENTERED OVER CENTRAL ROCKIES. THIS SHORTWAVE WILL ARRIVE OVER THE OZARKS MONDAY EVENING AS IT DEAMPLIFIES. LOW LEVEL FLOW WILL VEER IN RESPONSE TO THE APPROACHING UPPER LEVEL WAVE LATE MONDAY/EARLY TUESDAY...RETURNING MODIFIED GULF AIR THE MIDSOUTH. GFS PROGS PRECIPITABLE WATER VALUES NEAR 1.9 INCHES BY TUESDAY AFTERNOON. GFS AND ECMWF MODELS LIFT THE CENTER OF THE DEEP AND BROAD LONGWAVE TROF FROM THE ROCKIES INTO THE CENTRAL PLAINS BY WEDNESDAY... LOWERING HEIGHTS OVER MUCH OF CONUS. A SURFACE COLD FRONT WILL LAY OUT NEARLY PARALLEL TO THE SOUTHWEST FLOW ALOFT...BEFORE DROPPING THROUGH THE MIDSOUTH WITH A SHORTWAVE TROF PASSAGE LATE WEDNESDAY. GIVEN THE PREFRONTAL MOISTURE PLUME AND COLD FRONTAL PASSAGE... RAIN CHANCES APPEAR GOOD TUESDAY AND WEDNESDAY. BY LATE WEDNESDAY... THE GFS AND ECMWF BEGIN TO PART WAYS. THE GFS KEEPS A RIDGE WEST/TROF EAST PATTERN THROUGH THE WEEKEND...KEEPING THE MIDSOUTH IN DRY NORTHWEST FLOW ALONG. CONVERSELY...THE ECMWF DROPS SIGNIFICANT UPPER LEVEL ENERGY FROM WESTERN CANADA INTO THE THE FOUR CORNERS REGION BY FRIDAY...THEN EJECTS AN OPEN BUT HIGHLY AMPLIFIED TROF INTO THE CENTRAL AND SOUTHERN PLAINS BY LATE SATURDAY. THE ECMWF SOLUTION WOULD RESULT IN POTENTIALLY ACTIVE WEATHER ACROSS THE MIDSOUTH ON SATURDAY...A VERY DIFFERENT SOLUTION THAN THAT OF THE GFS. EXTENDED FORECAST PERIODS WERE HEAVILY WEIGHTED TOWARD THE ECMWF... GIVEN THE ECMWF/S GREATER RECENT RUN TO RUN CONSISTENCY. WITH THE LACK OF GFS CONCURRENCE...FORECAST CONFIDENCE IS BELOW AVERAGE FOR THE LATE WEEK PERIODS. PWB && .AVIATION... 12Z TAF SET PATCHY FOG IS OCCURRING AGAIN THIS MORNING AT KMKL REDUCING VSBYS TO MVFR OR IFR AT TIMES. FOG WILL LIFT AFTER 13Z. SCT TSRAS WILL DEVELOP TODAY ACROSS THE CWA AHEAD OF AN APPROACHING COLD FRONT. WILL CONTINUE MENTION OF VCTS FOR NOW. EXPECT GENERALLY VFR CONDITIONS UNLESS A TAF SITE IS AFFECTED BY A TSRA. AFTER 01Z...EXPECT TSRAS TO DIE OUT. NOT SURE ABOUT CLOUD COVER DURING THE EVENING INTO THE OVERNIGHT HOURS. RAP INDICATES THERE COULD BE SOME LOWER CIGS OCCUR DURING AT LEAST THE EVENING HOURS AND CURRENTLY ON SATELLITE THERE IS SOME LOWER CIGS IN OKLAHOMA ALONG FRONT. OTHER MODELS SCATTER CLOUDS OUT. FOR NOW WILL CONTINUE WITH VFR CONDITIONS BUT WILL CHANGE FROM SCT040 SCT120 TO BKN040. CAN/T RULE OUT SOME PATCHY FOG AT KMKL AGAIN LATE TONIGHT. LIGHT S WINDS WILL BECOME NE THIS EVENING. KRM && && .PRELIMINARY POINT TEMPS/POPS... MEM 81 60 80 59 / 30 10 10 10 MKL 79 57 80 54 / 20 20 0 0 JBR 77 57 77 54 / 40 10 10 10 TUP 83 60 80 59 / 10 10 0 0 && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. && $$
AREA FORECAST DISCUSSION...UPDATED
NWS BROWNSVILLE TX
929 PM CDT SUN OCT 13 2013 .DISCUSSION...MONITORING CONVECTION THAT HAS SO FAR REMAINED TO THE NORTHWEST OF THE CWA. HOWEVER TRENDS OVER THE LAST COUPLE OF HOURS IN WATER VAPOR IMAGERY SUGGEST THAT A RIPPLE IN THE SUBTROPICAL JET...WHICH IS BEING ENHANCED BY OUTFLOW OF TS OCTAVE WILL LEAD TO STRONGER DIFFLUENCE PUSHING SOUTHEAST AND HOLDING THROUGH SUNRISE. LOW LAYER ANALYSIS AND THE NAM12/RAP SUGGEST INCREASING CONVERGENCE OVER MAINLY JIM HOGG/ZAPATA COUNTY OVER THE NEXT COUPLE OF HOURS. THERE IS FAIRLY WEAK BUT NONZERO INSTABILITY AND DEEP MOISTURE WITH SATELLITE AND RAP PWAT ESTIMATES AROUND 2.2 INCHES WHICH IS REASONABLY IN LINE WITH 00Z REGIONAL BALLOON RELEASES. WITH AT LEAST SOME BAROCLINICITY IN THE 850/700MB LAYER MORE FOCUSED REGIONAL TROUGHING COULD SET UP ALONG OUR NORTHWESTERN ZONES THROUGH THE NIGHT AS WELL. CONSIDERING THE ABOVE HAVE RAISED PRECIP CHANCES THROUGH THE OVERNIGHT MAINLY IN ZAPATA/BROOKS/STARR/JIM HOGG COUNTIES. LOCAL FLOODING RISK STILL APPEARS LIMITED BY A STABILIZING BOUNDARY LAYER BUT WILL CONTINUE TO MONITOR. -JGG/GB && .PREV DISCUSSION... /ISSUED 622 PM CDT SUN OCT 13 2013/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...GUSTY SOUTHEAST WINDS WILL FALL TO AROUND 7 TO 10 KNOTS OVER THE NEXT FEW HOURS. CONVECTION IS EXPECTED TO REMAIN NORTHWEST OF THE TAF SITES BUT ISOLATED ACTIVITY IS POSSIBLE ACROSS JIM HOGG AND ZAPATA COUNTY THROUGH THE EARLY EVENING. DRIER AIR AROUND 3000 FT IS EXPECTED TO HELP KEEP CIGS VFR BUT PATCHY HIGH MVFR IS POSSIBLE...ESPECIALLY AROUND SUNRISE AND HAVE INCLUDED A TEMPO GROUP DURING THAT TIME PERIOD. CLOUD DECKS SHOULD RISE ABOVE 3000 FT AND BECOME SCATTERED TO FEW BY MID MORNING AS SOUTHEASTERLY WINDS INCREASE AND PERSIST THROUGH THE DAY ON MONDAY. /68-JGG/ PREV DISCUSSION... /ISSUED 319 PM CDT SUN OCT 13 2013/ SHORT TERM /NOW THROUGH MONDAY NIGHT/...H5 RIDGE CONTINUES TO SPIN JUST OT THE SOUTH...WITH MOISTURE CONTINUING TO WRAP AROUND IT. WEAK IMPULSE EXPECTED TODAY WENT FURTHER NORTH THAN FORECAST...SO SHOWERS HAVE BEEN ISOLATED AND HAVE FOR THE MOST PART MOVED OFF TO THE NORTH. MOISTURE IS FORECAST TO GET SHUNTED FURTHER NORTHWARD DURING THE NEXT 12 HOURS...WHILE MUCH DRIER AIR NOTED TO THE SOUTH ON WV IMAGERY WILL REPLACE IT STARTING TONIGHT. THIS SHOULD PUT AN END TO THE POP CHANCES FOR THE SHORT TERM PERIOD. TEMPERATURES WILL AGAIN RISE INTO THE LOW 90S TOMORROW WITH ANOTHER HUMID DAY IN STORE. LONG TERM /TUESDAY THROUGH SUNDAY/...THE 500 MB RIDGING IN PLACE OVER THE GULF OF MEX AND SOUTHERN TX WILL BE STEADILY ERODED AWAY LATER THIS WEEK AS A SERIES OF STRONG SHORT WAVES WILL DIG ACROSS THE WESTERN AND CENTRAL STATES. THIS WILL PUSH A COLD FRONT THROUGH DEEP SOUTH TX LATE WED NIGHT/EARLY THURS MORNING WITH A SECOND FRONT PUSHING ACROSS CENTRAL AND SOUTHERN TX THIS SATURDAY. AS THE MID LEVEL RIDGING ERODES AWAY THE DEEPER LAYER MOISTURE FEED (WHICH IS BEING ENHANCED FROM THE LEFT OVER MOISTURE FROM T.S. OCTAVE IN THE EASTERN PAC) WILL SHIFT STEADILY SOUTHWARDS AHEAD OF THE NEXT FRONT INCREASING THE CONV POTENTIAL DURING THE LATER HALF OF THE WEEK. THE OLD COLD FRONT WILL REMAIN STATIONARY TO THE SOUTH OF THE REGION ON SUN WITH BROAD HIGH PRESSURE SPREADING OVER MUCH OF THE CENTRAL AND EASTERN STATES. BOTH THE ECMWF AND GFS GENERALLY AGREE IN THE HANDLING OF THE SYNOPTIC FEATURES AND THE OVERALL MOISTURE TRENDS THROUGH THURS. AT THIS POINT THE GFS DEVIATES FROM THE ECMWF AND TRIES TO DEVELOP A SURFACE COASTAL LOW NEAR THE LOWER TX COASTLINE AND LIFTS THIS FEATURE SLOWLY NORTHEAST NEXT WEEKEND. THE ECMWF DOES NOT REFLECT THIS FEATURE AS WELL AND TENDS TO WANT TO DRY OUT THE AREA MUCH FASTER AS SURFACE RIDGING STRENGTHENS OVER THE REGION. FOR NOW WILL GO CLOSE TO THE GFS SOLUTION THROUGH THURS AND WILL LEAN TOWARDS THE ECMWF SOLUTION FOR THE WEEKEND. OVERALL CONFIDENCE FOR THE LONGER RANGE PERIOD IS ABOVE AVERAGE THROUGH AROUND THURS AND IS THEN ONLY AVERAGE AFTER THURS DUE TO THE MODEL DIFFERENCES. WILL GO FAIRLY CLOSE TO GFS MEX MOS TEMPS THROUGH THE WEEKEND AND WILL LEAN TOWARDS THE DRIER ECMWF POPS AFTER THURSDAY. MARINE...NOW THROUGH MONDAY NIGHT...MINIMAL CHANGE IN MARINE FORECAST THROUGH THE NEXT 36 HOURS. WEAK RIDGING CONTINUES ACROSS THE NORTHERN GULF...WHILE THE NEXT COLD FRONT ENTERS NORTH TEXAS. WINDS WILL REMAIN IN THE 10 TO 15 KNOT RANGE THROUGH MONDAY NIGHT...WHILE SEAS STAY GENERALLY BETWEEN 3 AND 4 FEET. TUESDAY THROUGH FRIDAY...A LIGHT TO MODERATE SE FLOW WILL PREVAIL TUES AND WED AHEAD OF THE NEXT FRONT. A MODERATE TO STRONG N-NE FLOW WILL DOMINATE IN BEHIND THE FRONT ON THURS. HOWEVER ONLY BORDERLINE SCA CONDITIONS MAY OCCUR AS THE STRONG PGF MAY BE FAIRLY SHORT LIVED. A MODERATE ONSHORE FLOW WILL PREVAIL INTO FRI AS SURFACE RIDGING SAGS OVER THE GULF OF MEX. THIS WILL MAINTAIN MODERATES SWELLS AS THE WEEKEND APPROACHES. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 68/59
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AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
901 PM CDT SUN OCT 13 2013 .UPDATE... TIMING OF FROST ADVISORY STILL ON TRACK. MADE MINOR TWEAKS TO TEMPERATURES AS A FEW LOW-LYING AREAS HAVE COOLED A BIT FASTER AFTER DECOUPLING THAN SURROUNDING LOCATIONS. MESONET SITES IN WESTERN MILWAUKEE AND OZAUKEE COUNTIES TRENDING WARMER THAN LOCATIONS FARTHER INLAND SO NO IMMEDIATE PLANS TO ADD THOSE NARROW COUNTIES...ESPECIALLY WITH RELATIVELY WARM ONSHORE FLOW DEVELOPING AFTER MIDNIGHT. FAR WESTERN SECTIONS OF THOSE COUNTIES COULD STILL SEE SOME FROST..BUT NOT ENOUGH TO ADD TO ADVISORY. && .AVIATION/06Z TAFS/... VFR CONDITIONS THROUGH THE OVERNIGHT WITH FROST AT INLAND TAF SITES. LATEST RAP FORECAST SOUNDINGS SUPPORTING PREVIOUS NAM RUNS WITH MVFR LAKE CLOUDS AROUND 2500 FT MOVING IN WITH INCREASING EASTERLY WINDS BETWEEN 14Z AND 15Z MONDAY AT KMKE AND KENW...WITH HEIGHTS BETWEEN 2800 AND 3000 FT AT KUES BETWEEN 16Z AND 17Z. WILL AWAIT ALL OF 00Z DATA..BUT 00Z NAM LOW-LEVEL RH FORECASTS INDICATE LOWER CLOUDS MAY MOVE IN MORE TOWARD 12Z. THEY ALSO INDICATE THE CLOUDS WOULD PUSH WEST OUT OF KMKE AND KENW BY 18Z. && .MARINE... LATEST NAM SURFACE WIND FORECAST SHOWS INCREASING EAST WINDS VEERING SOUTHEAST AROUND/SHORTLY AFTER MIDNIGHT...WITH THE INCREASING FETCH BUILDING WAVES TOWARD SMALL CRAFT CRITERIA OVERNIGHT INTO TUESDAY...ESPECIALLY NORTH OF MILWAUKEE AS WINDS TURN TO THE SOUTH. STILL EARLY FOR A HEADLINE BUT WILL KEEP POSSIBLE ADVISORY MENTION IN THE NEARSHORE FORECAST AND LET NEXT SHIFT HAVE A GOOD LOOK AT ALL OF THE 00Z DATA. && .PREV DISCUSSION... /ISSUED 359 PM CDT SUN OCT 13 2013/ VERY SHORT TERM...TONIGHT AND MONDAY. HIGH PRESSURE WILL MOVE EAST ACROSS THE AREA TONIGHT...THEN TO THE EAST ON MONDAY. THE HIGH WILL BRING QUIET WEATHER TO THE AREA. THE MAIN ISSUE WILL BE FROST POTENTIAL. MAINLY CALM WINDS AND CLEAR SKIES WITH THE CORE OF THE HIGH PASSING THROUGH TONIGHT WILL BRING IDEAL RADIATIONAL COOLING CONDITIONS. GIVEN THIS SETUP...WENT A FEW DEGREES BELOW MOST GUIDANCE FOR LOWS...AND WENT WITH LOWER TO MID 30S AWAY FROM LAKE MICHIGAN. THUS...WILL ISSUE A FROST ADVISORY FOR THE COUNTIES AWAY FROM LAKE MICHIGAN FROM 08Z TO 13Z MONDAY. ALSO INCLUDED SHEBOYGAN...RACINE AND KENOSHA COUNTIES FOR THEIR WESTERN AREAS...WHICH WILL SEE AREAS OF FROST WITH LOWS FALLING INTO THE MID 30S. OTHER ISSUE WILL BE LAKE EFFECT CLOUDS LATE TONIGHT AND MAINLY MONDAY ACROSS THE AREA. NAM/GFS/CANADIAN MODELS ALL SHOWING AN AREA OF ELEVATED RELATIVE HUMIDITY VALUES IN THE 1000/850MB LAYER SHIFTING WESTWARD ACROSS THE AREA DURING THIS TIME. NAM MOST AGGRESSIVE WITH THIS. DELTA T VALUES ARE FAVORABLE FOR LAKE EFFECT CLOUDS ON NAM...WITH GFS BORDERLINE. AFTER COORDINATION WITH CHICAGO OFFICE ADDED CLOUDS MOVING WEST INTO THE EASTERN PORTIONS OF THE AREA MAINLY ON MONDAY. MAY SEE DIURNAL CUMULUS DEVELOP INLAND AS WELL IN ADDITION TO THESE CLOUDS DURING THE DAY. PER 925MB TEMPERATURES...KEPT HIGHS IN THE UPPER 50S EAST...TO THE LOWER 60S WEST. SHORT TERM...MONDAY NIGHT THROUGH WEDNESDAY. SHORT TERM GUIDANCE IN REASONABLE AGREEMENT ON STRONG PUSH OF WARM AIR ADVECTION COINCIDENT WITH SURGE OF MOISTURE INTO SOUTHERN WISCONSIN FROM LATE MON NIGHT THROUGH TUESDAY. IN ADDITION...SHORT WAVE ROTATING AROUND UPSTREAM APPROACHING LOW PRESSURE PUSH OF WARM PASSES ACROSS SOUTHERN WI DURING THIS TIME RESULTS IN MODERATE LAYER Q-VECTOR CONVERGENCE OF UP TO 30 UNITS PASSING SWIFTLY ACROSS SRN WI. HENCE WL CONTINUE CATEGORICAL POPS ACROSS THE REGION. WL ALSO ADD SMALL CHANCE OF THUNDER AS ELEVATED LIFTED INDEX APPROACHES ZERO AND TOTAL TOTALS APPROACH 50. DRIER AIR ROTATING AROUND THE OCCLUDING UPPER LOW LOCATED TO THE WEST WILL END MOST OF THE SHOWERS DURING THE LATE MORNING AND AFTERNOON. WL CONTINUE SMALLER SHOWER THREAT TUESDAY NIGHT INTO WEDNESDAY AS SECONDARY LOW PRESSURE TROF SWINGS THROUGH SRN WI. LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY. UPSTREAM AMPLIFYING TROFING OVER SOUTH CENTRAL CANADA INTO NORTHERN PLAINS WILL RESULT IN LOW PRESSURE OVER GREAT LAKES AT START OF PERIOD TO WEAKEN AND SPEED OFF TO THE EAST AS IT BECOMES OPEN WAVE. HENCE CHANCE FOR LIGHT PRECIP DIMINISHES RAPIDLY OVER SOUTHERN WI WED AND WED EVE. OTHERWISE...ALL EXTENDED GUIDANCE IN REASONABLE AGREEMENT ON LONG WAVE TROFING BUILDING INTO THE CENTRAL CONUS LATE IN THE WEEK AND NEXT WEEKEND. HOWEVER DIFFERENCES REMAIN ON POSITION OF AMPLIFYING TROF AND RESULTING COLDER AIR PUSH INTO WI. ECMWF NOT AS AGGRESSIVE IN PUSH OF COLD AIR INTO THE REGION LATE IN THE WEEK DUE TO IT MAINTAINING SCENARIO WITH LONG WAVE TROF AXIS DEVELOPING UPSTREAM. MEANWHILE GFS HAS TROF AXIS BUILDING INTO WRN GTLAKES LATE IN THE WEEK WITH COLDER AIR SURGING IN FOR THE WEEKEND. LATEST GEM HAS JOINED THE FASTER GFS CAMP AS WELL. WPC BLENDED FIELDS USING AN ENSEMBLE MEAN OF THE ECMWF AND GEM. GFS 5DAY 500H MEANS CONTINUES TO SHOW NEGATIVE ANOMALY OF 100 METERS SETTLING OVER THE GREAT LAKES BY 00Z/18 AND EXPANDING TO 150 METERS BY 00Z/20. HENCE CONFIDENCE HIGH ON COLDER TEMPERATURES SETTLING INTO THE REGION WITH A GREATER LIKELIHOOD OF FROST/FREEZE. WL NEED TO KEEP SMALL POPS FOR LIGHT PRECIP FROM TIME TO TIME DUE TO WEAK PASSING SHORT WAVES/FRONTS IN FAST W TO NW FLOW. AVIATION /00Z TAFS/...HIGH PRESSURE IS EXPECTED TO SHIFT EASTWARD ACROSS THE REGION THROUGH MONDAY. THE HIGH WILL BRING QUIET WEATHER TO TAF SITES. LIGHT TO MODERATE NORTHWEST WINDS WILL SHIFT NORTH BY EVENING...THEN BECOME CALM/LIGHT TONIGHT...AND LIGHT TO MODERATE AND EASTERLY ON MONDAY. MAIN ISSUE WILL BE LAKE EFFECT CLOUDS AFFECTING EASTERN TAF SITES LATER TONIGHT INTO MONDAY MORNING. EXPECT MVFR CEILINGS TO MOVE INTO EASTERN SITES AFTER 12Z MONDAY...AND LINGER THROUGH MOST OF THE DAY. THESE MAY MOVE WEST NORTHWEST AND AFFECT MADISON AS WELL BY MID TO LATE MORNING. MENTIONED SCATTERED LOW CLOUDS IN TAFS AFTER 09Z IN THE EAST...WITH MVFR CEILINGS AFTER 12Z MONDAY. MADISON SHOULD SEE AT LEAST SCATTERED DIURNAL CUMULUS BY LATE MORNING INTO THE AFTERNOON. MARINE...HIGH WAVES OF 3 TO 5 FEET MAY DEVELOP ACROSS THE NEARSHORE WATERS OF LAKE MICHIGAN MONDAY NIGHT...AND LINGER TUESDAY INTO TUESDAY EVENING. A TIGHT PRESSURE GRADIENT DEVELOPING WITH PASSING LOW PRESSURE WILL CREATE INCREASING ONSHORE WINDS MONDAY NIGHT INTO TUESDAY. WINDS WILL SHIFT TO THE WEST TUESDAY NIGHT AND WEDNESDAY AND BECOME BRISK...AS THE PRESSURE GRADIENT TIGHTENS AGAIN. 15 TO 25 KNOT WINDS ARE POSSIBLE IN THIS TIME PERIOD. HIGHEST WAVES WOULD BE TOWARD THE OPEN WATERS. THUS...A SMALL CRAFT ADVISORY MAY BE NEEDED FROM MONDAY NIGHT THROUGH WEDNESDAY OR WEDNESDAY NIGHT. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...FROST ADVISORY FROM 3 AM TO 8 AM CDT MONDAY FOR WIZ046-047-051- 052-056>059-062>065-067>072. LM...NONE. && $$ UPDATE...REM TONIGHT/MONDAY AND AVIATION/MARINE...WOOD MONDAY NIGHT THROUGH SUNDAY...MBK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
643 PM CDT SUN OCT 13 2013 UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 227 PM CDT SUN OCT 13 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A LARGE HIGH PRESSURE SYSTEM GRADUALLY MOVING EAST OVER THE NORTHERN PLAINS TO MID-MISSISSIPPI VALLEY. LINGERING WEAK CYCLONIC FLOW AND THERMAL TROUGHING HAVE KEPT A STUBBORN STRATO-CU FIELD OVER THE NE THIRD OF THE STATE...THOUGH ITS GRADUALLY BREAKING UP. LOOKING UPSTREAM...MID AND HIGH CLOUDS ARE ADVANCING NE OVER THE PLAINS AHEAD OF THE NEXT STORM SYSTEM. SO WITH HIGH PRESSURE MOVING IN...FORECAST CONCERNS ARE CLOUDS...TEMPS AND FROST HEADLINES. TONIGHT...SURFACE HIGH PRESSURE WILL BE SETTLING ACROSS THE WESTERN GREAT LAKES REGION...PROVIDING MOSTLY CLEAR SKIES AND LIGHT WINDS. SHOULD SEE HIGH CIRRUS MOVE INTO NORTHERN WISCONSIN THIS EVENING...WHILE LIGHT EASTERLY FLOW WILL DEVELOP OVER THE LAKE MICHIGAN SHORELINE LATE. SOME CONCERN ABOUT LAKE CLOUDS MOVING INLAND THAT COULD MESS AROUND WITH FROST FORMATION OVER EAST-CENTRAL WISCONSIN. HOWEVER...THE EASTERLY FLOW WILL GENERALLY BE 5 KTS OR UNDER...AND LOCAL DATA SUGGESTS LAND BREEZES WILL DEVELOP THAT WILL KEEP LAKE INDUCED CLOUDS OFFSHORE. AS A RESULT...WILL LOWER TEMPS OVER EAST-CENTRAL WISCONSIN...WHERE LOCATIONS AWAY FROM LAKE MICHIGAN WILL LIKELY FALL INTO THE MIDDLE 30S. THESE CONDITIONS WILL LEAD TO THE POTENTIAL OF FROST SO WITH COLLAB FROM OTHER OFFICES...WILL HOIST A FROST ADVISORY EXCEPT FOR DOOR COUNTY. MONDAY...HIGH PRESSURE WILL REMAIN OVER THE AREA. IN ADDITION TO HIGH CLOUDS INCREASING FROM WEST TO EAST OVER THE AREA...EASTERLY WINDS STRENGTHEN SOME DURING THE MORNING...AND POSSIBLY ENOUGH TO PUSH A MID-LAKE CLOUD BAND INLAND. WILL INCREASE CLOUD COVER OVER EAST-CENTRAL WISCONSIN DURING THE MORNING. THINK THESE CLOUDS WILL GRADUALLY DISSIPATE DURING THE AFTERNOON...SO WILL CONTINUE TO SHOW MORE SUN EAST VERSUS WEST. HIGH TEMPS MAINLY IN THE MID TO UPPER 50S. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 227 PM CDT SUN OCT 13 2013 PATTERN OVER CONUS FOR THE NEXT WEEK TO CONSIST OF STRONG UPPER RIDGE ALONG THE WEST COAST WITH A BROAD UPR TROF ACROSS THE CENTRAL U.S. UNSETTLED WEATHER EXPECTED INTO WEDNESDAY AS UPPER TROF/ASSOCIATED SFC LOW AND COLD FRONT MOVE THRU THE GREAT LAKES. PCPN CHANCES CONTINUE...ALBEIT LOWER POPS THROUGH THE REMAINDER OF THE PERIOD AS COOLER AIR ALOFT SETTLES OVER THE REGION AND A SECONDARY WEAK COLD FRONT/TROF MOVE THRU. TEMPS TO BE NEAR NORMAL THRU THU AND THEN FALL BELOW NORMAL BY THE END OF THE WEEK. PCPN CHANCES INCREASE THROUGH THE NIGHT MON AS WAA PATTERN SPREADS EAST OVER THE REGION. MODELS CONTINUE TO SHOW DRY LAYER IN MID LEVELS THROUGH MUCH OF THE NIGHT MON. HAVE SLOWED PCPN A BIT EARLY EVENING...THOUGH LEFT REST OF PREVIOUS FORECAST STAND...STAYING DRY OVER THE EAST. WIDESPREAD PCPN EXPECTED TUE INTO TUE EVENING AS SURFACE LOW MOVES THROUGH STATE. DEEPER MOISTURE STRIPPED OUT LATER TUE NIGHT/WED LEADING TO LOWER POPS OR LIGHT PCPN. STILL HAVE TIMING DIFFERENCE THROUGH MUCH OF THE EXTENDED...THUS HAVE LEANED TOWARDS GFS ENSEMBLE FORECAST. HAVE BUMPED WINDS UP ON LAKE/BAY THROUGH THE EXTENDED GIVEN COLD AIR MASS MOVING IN. && .AVIATION...FOR 00Z TAF ISSUANCE ISSUED AT 643 PM CDT SUN OCT 13 2013 THE TRICKY PART OF THIS FORECAST IS TO WHAT EXTENT LAKE EFFECT CLOUDS FORM NEAR LAKE MICHIGAN AND THE BAY. SKIES WILL BE CLEAR EVERYWHERE FOR MUCH OF THE NIGHT BUT LAKE EFFECT CLOUDS ARE POSSIBLE AFTER 09Z AT MTW AND SUE AND PERHAPS OCONTO AND GREEN BAY AFTER 12Z. BEST GUESS IS THAT CLOUDS BASES WILL BE BETWEEN 3000 FT AND 4000FT. JUST INCREASING HIGH CLOUDINESS EXPECTED FURTHER WEST. && .GRB WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY FROM 3 AM TO 8 AM CDT MONDAY FOR WIZ038-039- 048>050. && $$ SHORT TERM.....MPC LONG TERM......TE AVIATION.......RDM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
342 PM CDT SAT OCT 12 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 341 PM CDT SAT OCT 12 2013 AT 3 PM...THE COLD FRONT...WHICH BROUGHT ISOLATED TO SCATTERED SHOWERS TO THE AREA OVERNIGHT...WAS JUST MOVING INTO LAKE MICHIGAN. THIS FRONT BECAME MORE ACTIVE AS IT RAN INTO DEEPER MOISTURE EAST OF THE FORECAST AREA. WATER VAPOR IMAGERY SHOWS A VORT MAX MOVING THROUGH CENTRAL MINNESOTA. THIS SYSTEM WAS PRODUCING AN AREA OF SHOWERS ACROSS EAST CENTRAL MINNESOTA AND CLOUDS ACROSS THE NORTHERN TWO-THIRDS OF MINNESOTA AND IN WEST-CENTRAL AND NORTHWEST WISCONSIN. WITH THE LOSS OF DIURNAL HEATING...THE HRRR CONTINUES TO SHOW THAT THE SHOWERS WILL RAPIDLY DISSIPATE AS THEY MOVE EAST INTO WISCONSIN THIS EVENING. WITH AN OPEN CELLULAR STRUCTURE TO THE CLOUDS ACROSS SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN...EXPECT THE CLOUDS TO ALL DISSIPATE WITH THE LOSS OF DIURNAL HEATING THIS EVENING. AFTER MIDNIGHT TONIGHT...THE MAIN CONCERN WILL BE WHETHER FROST WILL DEVELOP OR NOT. IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA... THE BUFKIT SOUNDINGS SHOW THE LOWEST 1 KM WILL HAVE THE WINDS DROP OFF INTO THE 5 TO 10 KNOT RANGE. HOWEVER THE NOCTURNAL BOUNDARY LAYER REMAINS VERY DRY. AS A RESULT...ONLY EXPECTING PATCHY FROST IN THESE AREAS. MEANWHILE IN CENTRAL AND NORTH-CENTRAL WISCONSIN... THE BOUNDARY LAYER IS VERY SHALLOW ONLY A COUPLE 100 FEET. MEANWHILE THE WINDS ALOFT REMAIN IN THE 10 TO 15 KNOT RANGE. WHILE THE WINDS ARE NOT OVERLY FAVORABLE...THERE IS MORE MOISTURE IN THE LOWEST LAYERS. LIKE IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA...IT LOOKS LIKE THE FROST WILL BE PATCHY TO SCATTERED. WITH NO AREAS OF WIDESPREAD FROST...THE CONSENSUS WAS NOT ISSUE A FROST ADVISORY. ON SUNDAY...A 1029 MB SURFACE HIGH WILL MOVE EAST ACROSS THE AREA. THIS HIGH PROVIDE SUNNY SKIES ACROSS THE REGION. BUFKIT SOUNDINGS SUGGEST THAT THE AREA WILL MIX TO AROUND 875 MB DURING THE AFTERNOON. WITH TEMPERATURES AT THIS LEVEL RANGING FROM 2 TO 5C... HIGH TEMPERATURES WILL LIKELY TOP OUT AROUND 60 DEGREES. THIS IS VERY CLOSE TO THE NORMAL HIGH FOR MID-OCTOBER. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 341 PM CDT SAT OCT 12 2013 ON SUNDAY NIGHT...A DEEP LAYER OF LIGHT WINDS REMAINS ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN. IN ADDITION SKIES WILL REMAIN MOSTLY CLEAR. THIS WILL ALLOW TEMPERATURES TO FALL INTO THE LOWER AND MID 30S ALONG AND NORTH OF INTERSTATE 94. THESE TEMPERATURES WILL BE COLD ENOUGH FOR SOME FROST TO DEVELOP. THE COVERAGE LOOKS TO BE MUCH MORE WIDESPREAD THAN TONIGHT. IF THIS CONTINUES...WILL LIKELY HAVE TO ISSUE A FROST ADVISORY. FROM MONDAY NIGHT INTO TUESDAY...THE 12.12Z MODELS CONTINUE TO SHOW THAT A TROUGH WILL MOVE NORTHEAST TOWARD THE FORECAST AREA. WHILE THEY CONTINUE TO BE IN GOOD AGREEMENT WITH THIS OCCURRING... MODELS HAVE CONTINUED TO SLOW ITS MOVEMENT INTO THE AREA. DURING THE EVENING...MODERATE TO STRONG 850 MB MOISTURE TRANSPORT AND STRONG SYNOPTIC FORCING DEVELOPS WEST OF THE MISSISSIPPI RIVER. AS THIS OCCURS...EXPECT THE RAPID DEVELOPMENT OF SHOWERS. MEANWHILE THE COMBINATION OF DRY AIR AND WEAK FORCING WILL KEEP MUCH OF WESTERN WISCONSIN DRY. FROM LATE MONDAY NIGHT INTO TUESDAY...THE AREA WILL SEE MODERATE MOISTURE TRANSPORT AND STRONG SYNOPTIC FORCING. AS A RESULT EXPECT THE RAIN TO CONTINUE THROUGH MUCH OF THIS TIME PERIOD. HOWEVER AS THE LOW MOVES OFF TO THE NORTHEAST...THERE ARE SOME INDICATIONS THAT DRY SLOT MAY MOVE INTO NORTHEAST IOWA DURING THE MID TO LATE AFTERNOON. IF THIS OCCUR...THERE WOULD LIKELY BE A DECREASE IN PRECIPITATION CHANCES IN THIS AREA. FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT...THE MAIN QUESTION CONTINUES TO BE WHERE WILL THE DEFORMATION BAND WILL BE LOCATED AND HOW FAST WILL IT MOVE NORTHEAST OUT OF THE AREA. LIKE THEIR PREDECESSORS...THE 12.12Z MODELS CONTINUE TO STRUGGLE WITH ITS LOCATION AND TIMING. DUE TO THIS...KEPT PRECIPITATION CHANCES RANGING FROM 16 TO 44 PERCENT. REGARDLESS WHETHER THERE IS ANY PRECIPITATION...THE CYCLONIC FLOW WILL KEEP CLOUDS ACROSS THE REGION. THESE CLOUDS WILL TEMPER HIGH TEMPERATURES INTO THE LOWER AND MID 50S AND KEEP LOW TEMPERATURES AROUND 40 DEGREES. BEYOND THIS TIME PERIOD...THE MODELS CONTINUE TO SHOW THAT A LONG WAVE TROUGH WILL DEVELOP ACROSS THE REGION. THIS TROUGH WILL KEEP TEMPERATURES BELOW-NORMAL INTO NEXT WEEKEND. HIGH TEMPERATURES WILL REMAIN IN THE LOWER AND MID 50S...AND LOW TEMPERATURES WILL BE IN THE 30S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1222 PM CDT SAT OCT 12 2013 SURFACE LOW PRESSURE IS MOVING INTO WESTERN ONTARIO EARLY THIS AFTERNOON. LARGE AREA OF WRAP AROUND CLOUDS FROM THE LOW IS EXTENDING SOUTH ACROSS MUCH OF MINNESOTA. LATEST VISIBLE SATELLITE IS SHOWING SOME DIURNAL CUMULUS FORMING ON THE SOUTHERN EDGE OF THIS CLOUD SHIELD. THE 12.15Z RAP AND 12.12Z NAM BUFKIT SOUNDINGS BOTH SHOW THE POTENTIAL FOR THESE DIURNAL CUMULUS TO FORM A VFR CEILING AT BOTH AIRPORTS DURING THE AFTERNOON. THESE CLOUDS SHOULD DISSIPATE LATE THIS AFTERNOON LEAVING BEHIND CLEAR SKIES FOR THE REMAINDER OF THE PERIOD AS HIGH PRESSURE BUILDS IN FROM THE WEST. THE CENTER OF THE HIGH WILL REMAIN SOUTH OF THE REGION OVERNIGHT SO NOT EXPECTING THE WINDS TO COMPLETELY STILL OFF...BUT KLSE BEING IN THE VALLEY COULD GO DOWN TO AN ALMOST CALM WIND. HIGH WILL STILL BE OVER THE REGION FOR SUNDAY MORNING TO CONTINUE THE CLEAR SKIES AND WEST TO NORTHWEST WINDS UNDER 10 KNOTS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...04
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND SUNDAY ISSUED AT 239 PM CDT SAT OCT 12 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A COLD FRONT MOVING EAST OVER CENTRAL WISCONSIN AND ABOUT TO ENTER EASTERN WISCONSIN. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP OVER EASTERN WISCONSIN AHEAD OF THE FRONT...THE HEAVIEST WHICH IS MOVING ACROSS THE LAKE MICHIGAN SHORELINE. CANNOT RULE OUT SHOWERS POPPING UP UNTIL THE FRONT EXITS...BUT LOOKS LIKE THE MOST WIDESPREAD COVERAGE WILL HAVE PASSED TO THE EAST BY PRESS ISSUANCE. BEHIND THE FRONT...A DRY SLOT IS PROVIDING A PERIOD OF CLEAR CONDITIONS OVER PARTS OF WESTERN WISCONSIN. BUT OVER MINNESOTA AND FAR WESTERN WISCONSIN...A LARGE AND SOLID STRATO-CU FIELD IS MOVING EAST. SOME SHOWERS FALLING OUT OF THE CLOUD MASS UNDER THE COLDER CLOUD TOPS. SMALL PRECIP CHANCES/CLOUDS/TEMPS ARE THE MAIN FORECAST CONCERN IN THE SHORT-TERM. TONIGHT...THE COLD FRONT WILL MOVE EAST OVER LOWER MICHIGAN WHILE NORTHEAST WISCONSIN WILL SEE THE DRY SLOT MOVE OVERHEAD. SKIES WILL BE CLEARING OVER NORTHEAST WISCONSIN AS A RESULT...WHICH WILL LEAD TO A QUIET BUT BREEZY NIGHT. FARTHER WEST...SOLID MVFR STRATUS DECK OVER MINNESOTA WILL MOVE NORTHEAST ACROSS WESTERN AND NORTHERN SECTIONS OF THE FORECAST AREA TONIGHT. COLD ADVECTION/THERMAL TROUGHING AND ENOUGH MOISTURE IN THE 850-700MB LAYER POINTS TOWARDS THIS CLOUD MASS HOLDING TOGETHER AS IT MOVES ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. SOME SHOWERS NOTED IN THE OBS...BUT ENHANCED CLOUD TOPS SUGGEST DEEPER MID-LEVEL MOISTURE IS PRESENT OVER MN THAN WHAT WILL BE AROUND WHEN THE STRATUS DECK ARRIVES. HAVE INCREASED CLOUD COVER AND MIN TEMPS TONIGHT...BUT STILL MAY NOT BE HIGH ENOUGH. WILL PASS CONCERNS TO THE EVENING CREW. LOWS MAINLY IN THE UPPER 30S TO LOW 40S. SUNDAY...IF IT HAS NOT ALREADY DONE SO...THE LOW STRATUS DECK WILL BE EXITING NORTHERN WISCONSIN EARLY SUNDAY MORNING. SOME RESIDUAL MOISTURE MAY LEAD TO A SCT CU DECK FORMING BY LATE MORNING OVER NORTH-CENTRAL WISCONSIN...BUT SHOULD SEE MOSTLY SUNNY CONDITIONS ELSEWHERE. HIGHS IN THE UPPER 50S TO LOWER 60S. .LONG TERM...SUNDAY NIGHT THROUGH SATURDAY ISSUED AT 239 PM CDT SAT OCT 12 2013 MODELS CONTINUE WITH SAME THOUGHTS THIS PERIOD AS AMPLIFIED YET COLDER PATTERN EXPECTED OVER AREA AS RIDGE LIES OFF WEST COAST AND DEEPENING TROF OVER THE EASTERN 2/3RDS OF CONUS. S/W ENERGY DROPPING SE OUT OF PACIFIC NORTHWEST INTO SOUTHWEST STATES EXPECTED TO CLOSE OFF OFF EARLY IN PERIOD IS FEATURE THAT BRINGS CONCERNS TO THIS FORECAST PERIOD. STILL SOME ISSUES WITH TIMING BETWEEN MODELS AND INDIVIDUAL RUNS OF MODELS. ECMWF SLOWEST WITH PCPN NOW HOLDING OUT TIL LATER TUE. WITH SYSTEM CUTTING OFF IT WOULD SUGGEST A SLOWER PROGRESSION. NEITHER GFS OR ECMWF IS REALLY FAVORED BY ENSEMBLE MEANS SO WILL GO WITH A GENERAL BLEND FOR TUE AND WED. HAVE TRENDED TOWARDS ECMWF FOR LATER PERIODS AS IT PULLS ENERGY/TROF BACK OVER THE SOUTHWEST STATES PER ENSEMBLES. THIS WOULD LEAD TO TEMPS A BIT WARMER THAN SEEN YESTERDAY OR CURRENT OPS GFS. IN NEAR TERM...HIGH PRESSURE OVER REGION ON SUNDAY NIGHT. LIGHT WINDS AND CLEAR SKIES TO LEAD TO COLD NIGHT. EXPECT TEMPS TO DROP INTO THE 30S OVER THE REGION...DROPPING TO BELOW FREEZING IN TYPICAL COLD SPOTS. PLEASANT FALL DAY EXPECTED MONDAY. EASTERLY GRADIENT TO PICK UP AS LOW DEEPENS IN THE PLAINS. THIS WILL MODERATE TEMPS SOME. MAY ALSO SEE SOME LAKE CLOUDS FROM TIME TO TIME MONDAY GIVEN STILL RELATIVELY WARM WATERS. HAVE BACKED OFF A BIT ON POPS MON NIGHT AS MODEL CROSS SECTIONS EVEN ON MORE AGGRESSIVE GFS HOLDING ONTO DRY WEDGE BETWEEN 900 AND 700 MB INTO TUE MORNING. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1218 PM CDT SAT OCT 12 2013 A COLD FRONT WILL PROGRESS ACROSS EASTERN WISCONSIN EARLY THIS AFTERNOON WHICH WILL END THE SHOWER AND THUNDERSTORM THREAT. A PERIOD OF CLEAR SKIES WILL THE FOLLOW IN THE WAKE OF THE FRONT UNTIL A BKN/OVC AREA OF MVFR CIGS ROTATES NORTHEAST ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN LATE THIS AFTERNOON THROUGH MUCH OF TONIGHT. WINDS WILL ALSO TURN GUSTY OUT OF THE SOUTHWEST THIS AFTERNOON AND THEN PARTIALLY DIMINISH EARLY THIS EVENING. THE MVFR CLOUD DECK TO EXIT THE REGION LATE TONIGHT...WHICH WILL LEAVE GOOD FLYING WEATHER FOR THE REST OF SUNDAY. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......TE AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1222 PM CDT SAT OCT 12 2013 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 250 AM CDT SAT OCT 12 2013 COLD FRONT TRUDGING ACROSS THE REGION EARLY THIS MORNING...MORE OR LESS RESTING ALONG THE MISSISSIPPI RIVER AT 06Z. EARLY CONVECTION AROUND THE FRONT HAS DIMINISHED WITH 88-D RADAR RETURNS DEPICTING ONLY VERY SPOTTY SHOWERS. THE FRONT AND PCPN SHOULD BE NEARLY EAST OF THE FORECAST AREA BY 12Z. MEANWHILE TO THE NORTH...AREAS OF SHOWERS WILL TRACK EAST/NORTHEAST ACROSS NORTHERN MN...ASSOCIATED WITH AN AREA OF LOW PRESSURE OVER CANADA. NONE OF THIS ACTIVITY IS EXPECTED TO DIP FAR ENOUGH SOUTH TO IMPACT THE LOCAL AREA. HIGH PRESSURE BUILDS IN TONIGHT...AND WILL HELP ROUND OUT THE WEEKEND WITH SUNSHINE. THE CLEAR SKIES AND ANTICIPATED LIGHT WINDS WILL HELP TEMPS TUMBLE THOUGH...WITH MID 30S EXPECTED ACROSS THE COLD PRONE/DRAINAGE AREAS OF CENTRAL AND NORTH-CENTRAL WI. MOSTLY ALONG AND NORTH/EAST OF THE I-94 CORRIDOR. IT WILL PROBABLY BE MORE PATCHY IN NATURE...BUT IF TEMPS LOOK LIKE THEY COULD BE A COUPLE DEGREES COLDER...A FROST ADVISORY WOULD BE NEEDED. MONDAY MORNING PRESENTS A SIMILAR SCENARIO. .LONG TERM...(MONDAY THROUGH FRIDAY) ISSUED AT 250 AM CDT SAT OCT 12 2013 OVERALL...PRETTY GOOD AGREEMENT BETWEEN THE GFS/ECMWF/GEM/NAM WITH BRINGING A RAINMAKER ACROSS THE REGION LATE MONDAY NIGHT...LIKELY LINGERING THROUGH WED. THERE ARE DIFFERENCES IN TIMING...WITH THE NAM A BIT FASTER THAN THE REST...A TAD MORE NORTH. ON THE WHOLE...ALL PROMISE A PERIOD OF WETTING...WITH 1/2 TO 1 INCH OF RAIN POSSIBLE. AN UPPER LEVEL SHORTWAVE WILL EJECT OUT OF THE WEST COAST TROUGH...SPINNING ACROSS THE DAKOTAS MONDAY...AND GRADUALLY SLIPPING WEST TO EAST ACROSS THE UPPER MISSISSIPPI TUE-WED. THE SYSTEM/S SFC LOW WILL TRACK INTO SOUTHERN MN ON TUE...GRADUALLY EXIT EAST WITH THE UPPER LEVEL TROUGH ON WED. FAIRLY STRONG QG CONVERGENCE THROUGH THE 850-300 MB LAYER WITH THE STORM SYSTEM...DEEPEST/STRONGEST ACROSS MN/NORTHERN WI...GENERALLY NORTH OF THE SFC LOW. GOOD SHOT OF LOW LEVEL WARM AIR ADVECTION ALSO ACCOMPANIES THE LOW...WITH A 50 KT 850 MB JET NOSING MOISTURE AHEAD OF THE SYSTEM. A LOT OF UPPER AIR/THERMODYNAMIC FORCING WITH THE STORM...AND AMPLE MOISTURE TO FUEL IT. RAIN REMAINS LIKELY AS A RESULT...WITH SOME AFOREMENTIONED TIMING/PLACEMENT CONCERNS FOR THE HIGHER CHANCES. UNSURE ON IF THERE WILL BE ANY ISOLATED/SCATTERED STORMS TO CONTEND WITH. NO INSTABILITY INDICATED VIA THE GFS...BUT THE DYNAMICS ARE PRETTY STRONG...AND THAT ALONE COULD BE STRONG ENOUGH TO SPARK A THUNDERSTORM OR TWO. FOR NOW...WILL KEEP STORMS OUT OF THE FORECAST. A TROUGH WILL HANG WEST OF THE EXITING SFC LOW FOR TUE NIGHT/WED...INTERACTING THE UPPER LEVEL ENERGY IN THE 500 MB SHORTWAVE. SHOWERS SHOULD CONTINUE AS RESULT...LIKELY FOCUSED AROUND THE SFC BOUNDARY. COLDER AIR FLOWS ACROSS THE UPPER MISSISSIPPI RIVER VALLEY FOR THU/FRI. COUPLE THIS WITH FAVORABLE LOW LEVEL LAPSE RATES AND LINGERING MOISTURE AND ISOLD/SCT SHOWERS ARE LIKELY. CURRENT PLACEMENT OF THE COLDER AIR/MOISTURE WOULD KEEP MOST OF THE SHOWERS ACROSS NORTHERN PARTS OF MN/WI...WITH SOME DIURNAL ELEMENTS TO THE SHOWERS ALSO PROBABLE. TEMPERATURES WILL CONTINUE TO TUMBLE. HIGHS BY THE END OF THE WORK WEEK WILL STRUGGLE TO REACH 50 IN AREAS TO THE NORTH. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1222 PM CDT SAT OCT 12 2013 SURFACE LOW PRESSURE IS MOVING INTO WESTERN ONTARIO EARLY THIS AFTERNOON. LARGE AREA OF WRAP AROUND CLOUDS FROM THE LOW IS EXTENDING SOUTH ACROSS MUCH OF MINNESOTA. LATEST VISIBLE SATELLITE IS SHOWING SOME DIURNAL CUMULUS FORMING ON THE SOUTHERN EDGE OF THIS CLOUD SHIELD. THE 12.15Z RAP AND 12.12Z NAM BUFKIT SOUNDINGS BOTH SHOW THE POTENTIAL FOR THESE DIURNAL CUMULUS TO FORM A VFR CEILING AT BOTH AIRPORTS DURING THE AFTERNOON. THESE CLOUDS SHOULD DISSIPATE LATE THIS AFTERNOON LEAVING BEHIND CLEAR SKIES FOR THE REMAINDER OF THE PERIOD AS HIGH PRESSURE BUILDS IN FROM THE WEST. THE CENTER OF THE HIGH WILL REMAIN SOUTH OF THE REGION OVERNIGHT SO NOT EXPECTING THE WINDS TO COMPLETELY STILL OFF...BUT KLSE BEING IN THE VALLEY COULD GO DOWN TO AN ALMOST CALM WIND. HIGH WILL STILL BE OVER THE REGION FOR SUNDAY MORNING TO CONTINUE THE CLEAR SKIES AND WEST TO NORTHWEST WINDS UNDER 10 KNOTS. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...RIECK LONG TERM....RIECK AVIATION...04
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1131 AM CDT SAT OCT 12 2013 .UPDATE...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WERE SHIFTING NORTH NORTHEAST THROUGH MAINLY SOUTHEAST WISCONSIN AT THIS TIME. THESE WERE BEING DRIVEN BY COLD FRONT MOVING EAST THROUGH THE AREA...ALONG WITH PASSING 500MB VORTICITY MAXIMUM...AND WEAK TO MODEST LOW LEVEL FRONTOGENESIS RESPONSE. AREA FORECAST SOUNDINGS SUPPORT CONTINUATION OF SHOWERS AND ISOLATED STORMS THROUGH MID AFTERNOON...UNTIL COLD FRONT/LOW LEVEL FRONTOGENESIS RESPONSE MOVES EAST OF THE AREA. HRRR AND OTHER HIGH RESOLUTION MODELS SHOW AN AREA OF SHOWERS BECOMING BETTER ORGANIZED OVER THE FAR EASTERN COUNTIES AND OVER LAKE MICHIGAN BETWEEN 20Z AND 22Z...SO CONTINUED TO HAVE THE HIGHEST POPS IN THAT AREA. CLOUDS WILL CLEAR AREA FROM WEST TO EAST BEHIND COLD FRONT BY SUNSET...WITH DOWNWARD MOTION FROM COLD AIR ADVECTION. SHOULD SEE HIGHS REMAIN IN THE MID TO UPPER 60S AHEAD OF THE FRONT...WITH VALUES SLOWLY FALLING BEHIND IT WITHIN THE COLD AIR ADVECTION. && .AVIATION/18Z TAFS/...SCATTERED SHOWERS WITH ISOLATED THUNDERSTORMS ARE EXPECTED AT EASTERN TAF SITES UNTIL AROUND 23Z. COLD FRONT WILL MOVE EAST THROUGH THE AREA THIS AFTERNOON...HELPING GENERATE THE PRECIPITATION. SOUTH WINDS AHEAD OF THE FRONT WILL SHIFT WEST BEHIND IT DURING THE AFTERNOON...WITH MVFR/VFR CLOUD DECK SCATTERING OUT FROM WEST TO EAST SOON AFTER. HIGH PRESSURE MOVING EAST INTO THE REGION TONIGHT AND SUNDAY WILL BRING VFR CONDITIONS...WITH WEAKENING WEST WINDS AND CLEAR SKIES. LIGHT NORTHWEST WINDS ARE EXPECTED ON SUNDAY...WITH SUNNY SKIES. && .MARINE...SMALL CRAFT ADVISORY CONTINUES FOR ALL OF THE NEARSHORE WATERS UNTIL 23Z. REPORT FROM LARGE BARGE CAPTAIN 2 MILES EAST OF RACINE INDICATED HIGH WAVES WERE OCCURRING...SO EXPANDED THE SMALL CRAFT ADVISORY FOR THE ENTIRE NEARSHORE WATERS UNTIL 23Z. BREEZY SOUTH SOUTHEAST WINDS WERE HELPING GENERATE 3 TO 6 FOOT WAVES IN THE NEARSHORE WATERS. WINDS WILL VEER SOUTHWEST TO WEST LATE THIS AFTERNOON AND EARLY EVENING...AS THE COLD FRONT MOVES EAST THROUGH THE AREA. WINDS WILL ALSO DIMINISH DURING THIS TIME...ALLOWING WAVES TO SUBSIDE BELOW 4 FEET BY EVENING. && .PREV DISCUSSION... /ISSUED 343 AM CDT SAT OCT 12 2013/ SHORT TERM... TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM TO HIGH DECENT SHORTWAVE AND COLD FRONT WILL BRING A ROUND OF SHOWERS TO SOUTHERN WISCONSIN TODAY. HAVE ALREADY SEEN A SHOWER OR TWO IN THE WEST AND EXPECTING COVERAGE WILL PICK UP INTO THE MORNING. BEST CHANCE SEEMS TO BE IN THE EASTERN TWO-THIRDS OF THE FORECAST AREA MID MORNING INTO EARLY AFTERNOON AS BETTER LOW LEVEL FRONTOGENESIS AND UPPER DIVERGENCE FROM REAR JET ENTRANCE REGION MOVE THROUGH. GIVEN SOME LIGHTNING UPSTREAM AND ELEVATED CAPE IN SOUNDINGS...LEFT ISOLATED THUNDER IN THE FORECAST. THERE WILL BE A PRETTY GOOD PUNCH OF DRY AIR BEHIND THE FRONT THIS AFTERNOON...SO SHOULD SEE SKIES CLEAR PRETTY QUICKLY...WITH MOSTLY SUNNY SKIES EARLY AFTERNOON WEST AND LATE AFTERNOON EAST. ALREADY UPPER 50S AND LOW 60S MOST PLACES...EVEN MID TO UPPER 60S WEST...SO HIGHS IN THE UPPER 60S TO AROUND 70 STILL SEEM REASONABLE. WILL SEE MOSTLY CLEAR SKIES AND NEAR NORMAL TEMPS TONIGHT AS HIGH PRESSURE MOVES INTO THE AREA FROM THE WEST. SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE HIGH. UPPER LEVEL RIDGE AND SURFACE HIGH WILL DRIFT ACROSS THE GREAT LAKES REGION SUNDAY AND MONDAY. SUNNY SKIES...DRY AIR AND 925MB TEMPS AROUND 8C-9C WILL LEAD TO HIGHS IN THE LOWER 60S. WITH LIGHT WINDS...SUNDAY NIGHT LOWS WILL DIP INTO THE MID 30S INLAND FROM THE LAKE. KEPT THEN MENTION OF PATCHY FROST FOR MUCH OF THE AREA. LONG TERM... MONDAY NIGHT THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM. A HIGH-AMPLITUDE UPPER LOW OVER THE WESTERN U.S. WILL BRING ANOTHER DEEP SURFACE LOW ACROSS THE PLAINS AND INTO THE GREAT LAKES REGION AS IT OCCLUDES AND WEAKENS. MODELS ARE TRENDING SLOWER WITH THE PRECIP ARRIVAL IN SOUTH CENTRAL WI UNTIL EARLY TUESDAY MORNING NOW...WHICH MAKES SENSE GIVEN THE DRY AIR IN PLACE OVER THE GREAT LAKES. PRECIP CHANCES WILL CONTINUE TO BE HIGHER TOWARD CENTRAL WI RATHER THAN SOUTHERN WI AS A SECONDARY SURFACE LOW IS FORECAST TO TRACK RIGHT ACROSS THE MKX FORECAST AREA. THE DRY AIR WILL WRAP INTO SOUTHERN WI TUE NIGHT AS THE SYSTEM TRACKS EASTWARD. LIGHT SHOWERS AND CLOUDS WILL LINGER OVER CENTRAL AND SOUTHERN WI THROUGH AT LEAST WEDNESDAY MORNING...BUT POTENTIALLY THROUGH THURSDAY MORNING IF THE SLOWER 00Z ECMWF SOLUTION PANS OUT. FRIDAY AND BEYOND...FORECAST CONFIDENCE MEDIUM. ANOTHER UPPER TROUGH WILL DROP DOWN OUT OF WESTERN CANADA AND SETTLE OVER THE UPPER MIDWEST THURSDAY NIGHT THROUGH THE WEEKEND. 850MB TEMPS ARE EXPECTED TO DROP TO AROUND -2C. THIS MEANS HIGHS IN THE 50S FOR FRIDAY AND SATURDAY...AND A POTENTIAL WIDESPREAD FREEZE SATURDAY NIGHT. OF COURSE...THERE ARE MODEL DIFFERENCES AND RUN-TO-RUN INCONSISTENCIES THAT FAR OUT AND CLOUDS AND PRECIP COULD INHIBIT THE FREEZE. STAY TUNED. AVIATION/12Z TAFS/... WILL SEE SHOWERS AND A FEW RUMBLES OF THUNDER THIS MORNING...AFFECTING AREAS WEST FIRST AND THEN WINDING DOWN IN THE EAST BY EARLY OR MID AFTERNOON. COULD SEE SOME BRIEF MVFR CIGS AS THE COLD FRONT AND SHOWERS MOVE THROUGH...BUT OTHERWISE VFR CONDITIONS WILL CONTINUE THROUGH THE DAYTIME AND OVERNIGHT HOURS. MARINE... THE CURRENT SMALL CRAFT ADVISORY NORTH OF PORT WASHINGTON STILL SEEMS REASONABLE. WILL SEE BREEZY SOUTHERLY WINDS TODAY WITH GUSTS TO AROUND 20 KNOTS. THESE PERSISTENT WINDS WILL KEEP WAVES OF 3 TO 5 FEET ACROSS THIS AREA INTO THE AFTERNOON. WINDS WILL EVENTUALLY VEER TO THE SOUTHWEST THIS AFTERNOON AND EASE A BIT...ALLOWING THE WAVES TO SUBSIDE SOME BY EVENING. COULD SEE SOME HIGHER WAVES LINGER A BIT LONGER THAN PREVIOUSLY EXPECTED...SO WILL EXTEND THE ADVISORY EXPIRATION TIME FROM 20Z TO 23Z. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...NONE. LM...SMALL CRAFT ADVISORY UNTIL 6 PM CDT THIS EVENING FOR LMZ643>646. && $$ UPDATE...WOOD TODAY/TONIGHT AND AVIATION/MARINE...DDV SUNDAY THROUGH FRIDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1151 PM CDT FRI OCT 11 2013 .UPDATE... ISSUED AT 910 PM CDT FRI OCT 11 2013 CHANGES ARE ON THE WAY AS A COLD FRONT WILL COME THROUGH THE REGION TONIGHT. A FIRST ROUND OF ISOLATED TO SCATTERED SHOWERS HAS MOVED INTO NW WI/SE MN/NE IA ALONG A WEAKENING LEAD MID LEVEL TROUGH. FURTHER TO THE WEST...A NARROW BAND OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG A STRONG FRONTOGENETIC BAND ALONG THE SURFACE COLD FRONT. INSTABILITY IS RATHER LIMITED WITH 12.01Z LAPS ANALYSIS SHOWING ABOUT 500 J/KG OF MUCAPE ACROSS SOUTH CENTRAL MINNESOTA. RECENT MESO MODELS SEEM TO HAVE A DECENT IDEA OF SHOWING THE LATEST DEVELOPMENT ALONG THE COLD FRONT WITH A GRADUAL WEAKENING OF THE INSTABILITY/FGEN ALONG/AHEAD OF THE FRONT OVERNIGHT. LOW LEVEL TO DEEP WIND SHEAR IS MORE THAN SUPPORTIVE OF SEVERE WEATHER...BUT THE LACK OF INSTABILITY AND DEEP FORCING ABOVE THE SURFACE/LOW LEVELS WILL KEEP THIS CONVECTION LOW TOPPED AND NOT SEVERE. ONCE THE FRONT MOVES THROUGH...WINDS WILL SHIFT TO THE WEST AND REMAIN GUSTY ON INTO THE AFTERNOON SATURDAY. HAVE BUMPED UP THE GUSTS THERE BUT IT DOES NOT LOOK HIGH ENOUGH TO WARRANT AN ADVISORY. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 335 PM CDT FRI OCT 11 2013 AT 3 PM...A 990 MB SURFACE LOW WAS LOCATED JUST NORTH OF PIERRE SOUTH DAKOTA. DURING THE PAST 3 HOURS...MSAS DATA SHOWS THAT THE SURFACE PRESSURE HAS FALLEN 4 MB ACROSS NORTHEAST SOUTH DAKOTA. MEANWHILE THE PRESSURE HAS RISEN 6 MB ACROSS THE NEBRASKA PANHANDLE. LAPS SHOWS THE TROPOSPHERIC FOLD EXTENDING DOWN 800 MB. MEANWHILE FURTHER SOUTHEAST...THERE IS A 1019 MB SURFACE HIGH CENTERED OVER KENTUCKY. THE TIGHT SURFACE PRESSURE GRADIENT BETWEEN THESE TWO SYSTEMS HAS RESULTED IN WIND GUSTS AS HIGH AS 41 MPH /149 PM/ AT ROCHESTER INTERNATIONAL AIRPORT AND 39 MPH /133 PM/ AT THE DODGE CENTER AWOS. A BAND OF SHOWERS AND ISOLATED THUNDERSTORMS CONTINUES TO BE LOCATED ACROSS NORTH-CENTRAL IOWA AND SOUTH-CENTRAL MINNESOTA. THIS IS LOCATED IN AN AREA OF DEEP MOISTURE CONVERGENCE. FOR TONIGHT...THE LATEST RAP SHOW THAT THE 850 MB MOISTURE TRANSPORT WILL GRADUALLY WEAKEN AND SHIFT NORTHEAST INTO NORTHERN WISCONSIN THIS EVENING. IN ADDITION...THE 900 TO 800 MB FRONTOGENESIS WILL GRADUALLY WEAKEN AS IT MOVES EAST ACROSS THE FORECAST AREA. THIS WILL RESULT IN THE ECHO COVERAGE BECOMING MORE SCATTERED. THIS SHOWS UP WELL IN THE RAP...NMM...AND ARW. AS A RESULT...KEPT THE PRECIPITATION CHANCES IN THE 15 TO 24 PERCENT RANGE. ML CAPES GRADUALLY DECREASE FROM AROUND 500 J/KG LATE THIS AFTERNOON TO LESS THAN 200 J/KG AFTER MIDNIGHT. DUE TO THIS...CONFINED THE ISOLATED THUNDERSTORMS TO THE EVENING. LIKE YESTERDAY...IT APPEARS THAT THE SHEAR WILL BE TOO GREAT FOR THE AMOUNT OF INSTABILITY AVAILABLE...THUS ANY THUNDERSTORMS THAT DO HAPPEN DEVELOP WILL LIKELY GET SHEARED APART QUICKLY. WITH LOSS OF DIURNAL HEATING LATE THIS AFTERNOON AND EARLY EVENING...EXPECT THE WIND GUSTS TO QUICKLY WANE. ON SATURDAY MORNING...THE 11.12Z MODELS APPEAR TO BE JUST A BIT SLOWER AT MOVING THE FRONT OUT OF THE AREA. AS A RESULT...HELD ONTO A SLIGHT CHANCE OF SHOWERS IN CENTRAL AND SOUTHWEST WISCONSIN THROUGH 12.14Z. ON SATURDAY EVENING...ANOTHER SHORT WAVE TROUGH MOVES EAST THROUGH THE REGION. LIKE YESTERDAY...THE BEST SYNOPTIC FORCING AND MOISTURE LOOKS TO BE WELL NORTH OF THE FORECAST AREA. AS A RESULT...KEPT THE FORECAST DRY. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 335 PM CDT FRI OCT 11 2013 ON SATURDAY NIGHT...A CANADIAN HIGH WILL BUILD ACROSS THE AREA. WITH THE CENTER OF THIS HIGH BEING LOCATED MORE ACROSS IOWA THAN OUR FORECAST AREA. THINKING THAT THERE MIGHT BE JUST ENOUGH MIXING IN THE BOUNDARY LAYER TO PREVENT THE TEMPERATURES BOTTOMING OUT AS MUCH AS THEY WILL BE UNDERNEATH THE CORE OF THE HIGH. AS A RESULT... KEPT LOW TEMPERATURES IN THE 35 TO 42 DEGREE RANGE. THE WARMEST TEMPERATURES WILL BE FOUND IN THE MISSISSIPPI AND WISCONSIN RIVER VALLEYS. MEANWHILE THE REMAINDER OF THE AREA WILL BE COLD ENOUGH FOR SOME FROST TO DEVELOP. ON SUNDAY NIGHT...THE COMBINATION OF LIGHT WINDS AND MOSTLY CLEAR SKIES ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN WILL ALLOW TEMPERATURES TO FALL INTO THE MID 30S. THESE TEMPERATURES WILL BE COLD ENOUGH FOR SOME FROST TO DEVELOP. FROM MONDAY AFTERNOON THROUGH WEDNESDAY...THE MODELS CONTINUE TO LOW THAT A CLOSED 500 MB LOW WILL MOVE THROUGH THE UPPER MISSISSIPPI RIVER VALLEY. THE MAIN QUESTION IS WHEN EXACTLY WILL THIS OCCUR. THE 11.12Z ECMWF IS A BIT SLOWER THAN ITS PREVIOUS RUN AND SLOWER THAN SOME OF THE OTHER DETERMINISTIC MODELS. AS RESULT NOT EXACTLY SURE WHICH TIME PERIOD /MONDAY NIGHT...TUESDAY... OR BOTH/ TO GO WITH CATEGORICAL PRECIPITATION CHANCES /80 TO 100 PERCENT/. WITH THIS UNCERTAINTY...JUST STAYED WITH THE ALL BLEND SOLUTION. A COUPLE OF DAYS AGO...IT LOOKED LIKE WE WOULD POTENTIALLY SEE SOME THUNDERSTORMS AHEAD OF THIS LOW...BUT THE MODELS NOW SUGGEST THAT WE WILL ONLY SEE RAIN FROM THIS SYSTEM. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1151 PM CDT FRI OCT 11 2013 A COLD FRONT MOVING THROUGH THE REGION WILL BRING WINDS AROUND FROM THE SOUTHEAST TO THE WEST TONIGHT AS IT PASSES. SHOWERS AND THUNDERSTORMS THAT HAD DEVELOPED AHEAD OF IT IN A THIN LINE HAS STARTED TO FALL APART AS CONVECTION FURTHER SOUTH IN IOWA HAS TAKEN OVER SOME OF THE MOISTURE RETURN. RST HAS THE GREATER CHANCES OF HAVING SOME OF THE CURRENT SHOWERS IN ITS VICINITY...BUT AM GROWING MORE CONFIDENT THAT THEY WILL NOT REACH LSE. WINDS WILL BECOME GUSTY OUT OF THE WEST AT BOTH SITES WITH SOME GUSTS IN THE 20-30KT RANGE IN THE AFTERNOON. EXPECT THAT SOME DIURNAL CUMULUS WILL DEVELOP AS WELL IN THE 3-5KFT RANGE. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...HALBACH SHORT TERM...BOYNE LONG TERM...BOYNE AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS RIVERTON WY
933 PM MDT SUN OCT 13 2013 .UPDATE... ADDED CODY FOOTHILLS AND NORTHERN JOHNSON COUNTY INTO A WINTER WEATHER ADVISORY. THE FORMER STARTS IMMEDIATELY AS RAIN IS ALREADY CHANGING TO SNOW ACROSS THE CODY FOOTHILLS. LOOKS LIKE CODY PROPER WILL BE BELOW ADVISORY...BUT MEETEETSE WILL LIKELY SEE ADVISORY AMOUNTS. THIS IN ADDITION TO WINDY NORTHERLY WINDS DEVELOPING WILL MAKE TRAVEL DIFFICULT...ESPECIALLY NEAR MEETEETSE. NORTHERN JOHNSON SHOULD CHANGE OVER TO SNOW BY AROUND SUNRISE...WITH MARGINAL ADVISORY SNOWFALL AMOUNTS. HOWEVER...VERY STRONG NORTHWEST WINDS WILL DEVELOP WHICH COULD CAUSE SOME TRAVEL PROBLEMS IN RURAL AREAS MONDAY. WILL HAVE THE ADVISORY FOR NORTHERN JOHNSON RUN FROM 6 AM MONDAY THROUGH MIDNIGHT TUESDAY. THIS LINES UP WITH THE BIGHORN MTS WARNING AND CASPER MTN ADVISORY TIMING. THE GREEN AND RATTLESNAKE...THERMOPOLIS AND LANDER ZONES COULD POSSIBLE NEED ADVISORIES...BUT WILL LATE THE OVERNIGHT SHIFT TAKE ANOTHER LOOK BEFORE DECIDING. TWEAKED POPS AND SNOWFALL AMOUNTS...AND EVENING PACKAGE IS ALREADY OUT. && .PREV DISCUSSION... /ISSUED 422 PM MDT SUN OCT 13 2013/ SHORT TERM...TONIGHT THROUGH MONDAY MAIN TROUGH AXIS IS LOOMING TO OUR WEST OVER IDAHO...NEVADA AND UTAH. THIS TROUGH WILL BE RESPONSIBLE FOR ACCUMULATING SNOW...MAINLY IN OUR MOUNTAINS...AS WELL AS THE LOWER ELEVATIONS OF JOHNSON COUNTY TONIGHT THROUGH MONDAY EVENING. CURRENTLY WE ARE UNDER THE SOUTHWEST UPPER DIFLUENT UPPER FLOW ASSOCIATED WITH THE LEFT FRONT QUAD OF THE JET WHICH IS RESPONSIBLE FOR LIGHTNING ALONG THE FAR WESTERN BORDER OF WYOMING FROM WEAK CONVECTIVE CELLS. THIS MORE CONVECTIVE ACTIVITY HAS REPLACED THE MORE STRATIFORM PRECIP ASSOCIATED WITH THE WEAK ISENTROPIC LIFT IN THE WEST. A CIRCULATION IS EVIDENT ON PIH RADAR IN EASTERN IDAHO JUST WEST OF THE CONVECTION WITH THE RUC INDICATING INCREASING INSTABILITY. HOWEVER...THE GFS...NAM AND THE ECMWF ALL AGREE ON KEEPING THE MAIN JET ENERGY WELL TO THE SOUTH TRACKING ACROSS THE 4 CORNERS AREA LATE TONIGHT WITH THE VORT ENERGY STRENGTHENING IN THE NORTHERN AND CENTRAL PLAINS MONDAY. THE SURFACE FLOW IS OUT OF THE NORTHEAST ATTM...EAST OF THE DIVIDE...BUT AT MAINLY LIGHT SPEEDS. ONCE THE MAIN LOW OVER NEBRASKA/SOUTH DAKOTA STARTS TO BOMB...THE NORTH WINDS EAST OF THE DIVIDE WILL STRENGTHEN AND THUS INCREASE UPSLOPE SNOWFALL POTENTIAL. THE GFS INDICATES 3 SEPARATE SUBTLE CIRCULATIONS AT 700MB THAT WILL TRACK EAST ACROSS VARIOUS PORTIONS OF WYOMING TONIGHT...NOT THE MOST ORGANIZED SYSTEM WITH ASSOCIATED Q VECTOR FORCING AND WEAK ISENTROPIC LIFT. WITH THE 700MB CIRCULATIONS TRACKING ACROSS OUR CWA...BUT WITH THE MAIN ENERGY WELL TO OUR SOUTH...THE THINKING WAS ADVISORY AMOUNTS OF SNOWFALL FOR MOST OF THE MOUNTAIN ZONES EAST OF THE DIVIDE...NAMELY THE WIND RIVER...ABSAROKA AND BIG HORN MOUNTAINS AS WELL AS CASPER MOUNTAIN. THE BIG HORNS AND CASPER MTN WILL LIKELY LAG BEHIND ROUGHLY SIX HOURS COMPARED TO THE WINDS AND THE ABSAROKAS. DECIDED TO ISSUE A WINTER STORM WARNING FOR THE BIG HORN MOUNTAINS TO ACKNOWLEDGE THE 30 TO 40 MPH WIND GUSTS...THE HIGH END SNOW ADVISORY AMOUNTS AND ALSO TAKING INTO ACCOUNT THE TIME OF YEAR AND ALL THE HUNTERS THAT WILL BE NEGOTIATING THE WINTER CONDITIONS. THE BULK OF THE COLDEST 700MB AIR WILL COME CLOSEST TO JOHNSON COUNTY WHERE ADVISORY SNOW AMOUNTS ARE INDICATED FOR THAT ZONE FOR MONDAY AND MONDAY EVENING. THE MOS GUIDANCE INDICATES ACCUMULATING SNOWFALL FOR BYG AND SHR BUT NONE FOR THE OTHER MOS GUIDANCE FORECAST POINTS WHERE 700MB TEMPS ARE PROGGED BY THE NAM TO BE -9.5C IN NORTHERN JOHNSON COUNTY 00Z TUESDAY. NOT ONLY IS ACCUMULATING SNOW EXPECTED FOR THE LOWER ELEVATIONS OF JOHNSON COUNTY BUT STRONG NORTH WINDS OF 30 TO 40 MPH WITH SOME GUSTS OF 50 MPH ARE EXPECTED THERE AS WELL ON MONDAY ONCE THE STORM BOMBS TO THE EAST. THE NIGHT SHIFT WILL NEED TO DECIDE WHETHER OR NOT THE LOWER ELEVATIONS OF JOHNSON COUNTY AND THE GREEN MTNS...FOR THAT MATTER...NEED A HILITE FOR MONDAY AND MONDAY EVENING. LONG TERM...MONDAY NIGHT THROUGH SUNDAY AFTER SOME LINGERING FLURRIES...MAINLY EAST OF THE DIVIDE...SURFACE HIGH PRESSURE WILL BEGIN TO BUILD OVER WYOMING LATE MONDAY NIGHT AND TUESDAY. THE WEST AND NORTH SHOULD CLEAR OUT FIRST...RESULTING IN A VERY CHILLY TUESDAY MORNING. LOW LEVEL CLOUDS COULD REMAIN OVER JOHNSON AND NATRONA COUNTIES EARLY TUESDAY MORNING BEFORE A CLEARING SKY. MOST OF THE FORECAST AREA WILL STILL SEE A SUNNY SKY BY TUESDAY AFTERNOON. NORTHWEST FLOW THEN SETS UP ALOFT OVER WYOMING. IT WILL BE DRY AND COLD TUESDAY NIGHT THROUGH WEDNESDAY NIGHT PER MODELS. FURTHER IN THE EXTENDED WILL HAVE TO WATCH FOR A FEW QUICK HITTING SHORTWAVES IN THIS NORTHWEST FLOW...BEGINNING EARLY THURSDAY. AS IT LOOKS NOW... WEST CENTRAL WYOMING WILL BE UNDER INFLUENCE OF THE DRIER NORTHERLY STREAM INTO NEXT WEEKEND. THE ECMWF IS MORE ROBUST WITH THESE EMBEDDED SHORTWAVES...BUT PREFER THE DRIER GFS FOR NOW. IF ANY AREA WERE TO SEE SOME SNOW SHOWERS IN THIS PATTERN...IT WOULD BE THE BIGHORN MOUNTAINS. THEREFORE...SLIGHTLY HIGHER POPS FOR BIGHORN MOUNTAINS THURSDAY AND FRIDAY. OTHERWISE...TEMPERATURES SHOULD BE NEAR OR SLIGHTLY BELOW NORMAL THROUGH THE PERIOD. AVIATION.../00Z ISSUANCE/ WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES SCATTERED MOUNTAIN SNOW SHOWERS...VALLEY RAIN AND SNOW SHOWERS AND EVEN ISOLATED THUNDERSTORMS WILL INCREASE IN COVERAGE LATE THIS AFTERNOON AND EARLY EVENING. PERIODS OF IFR/MVFR CONDITIONS WILL OCCUR IN THE MOUNTAINS...BECOMING MORE PREVALENT LATE THIS AFTERNOON INTO THE OVERNIGHT HOURS. THE RAIN AND SNOW MIX IN THE VALLEYS WILL TURN TO ALL SNOW TONIGHT. THE MOST IMPACTED TAF SITE WITH THIS ACTIVITY WILL BE KJAC TERMINAL...BUT WILL HOLD OFF PREVAILING MVFR CONDITIONS UNTIL THIS EVENING FOR THE KJAC TERMINAL. MOUNTAINS WILL BE OBSCURED THROUGH THE PERIOD WITH LIFR CONDITIONS MUCH OF THE TIME. EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES MOUNTAIN SNOW/VALLEY RAIN SHOWERS WILL SPREAD EAST OF THE DIVIDE THIS EVENING. TAF SITES SHOULD GENERALLY REMAIN VFR LATE THIS AFTERNOON...BUT THIS WILL CHANGE TONIGHT. WIDESPREAD MVFR/IFR CONDITIONS ARE LIKELY TO DEVELOP FROM NORTH TO SOUTH TONIGHT...AS A COLD FRONT SWEEPS SOUTHWARD WITH AN INCREASING PRECIPITATION SHIELD. RAIN IN THE LOWER ELEVATIONS WILL CHANGE TO SNOW IN MOST AREAS BY 12Z MONDAY EXCEPT KCPR WILL LIKELY HOLD OFF UNTIL 15Z. MOUNTAINS ALONG THE DIVIDE WILL BE OBSCURED FOR MUCH OF FORECAST PERIOD...WHILE OTHER MOUNTAINS WILL BECOME OBSCURED THIS EVENING AND REMAIN SOCKED IN THROUGH MONDAY. PLEASE SEE THE AVIATION WEATHER CENTER FOR THE LATEST INFORMATION ON ICING FORECASTS. FIRE WEATHER... IRE WEATHER WILL NOT BE A FACTOR IN THE NEXT DAY OR TWO DUE TO LOW PRESSURE OVER THE CENTRAL AND NORTHERN ROCKIES. THE LOW PRESSURE...AT THE SURFACE AND ALOFT...WILL RESULT IN AREAS OF SNOW. WINTER STORM WARNINGS AND ADVISORIES HAVE BEEN ISSUED FOR SOME OF THE WEST CENTRAL WYOMING MOUNTAIN RANGES. THIS SNOW WILL TAPER OFF BY MONDAY NIGHT. TUESDAY THROUGH WEDNESDAY WILL HAVE COOL TEMPERATURES AND VERY LITTLE WIND OR MIXING ACROSS THE REGION. && .RIW WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT MDT MONDAY NIGHT WYZ022. WINTER WEATHER ADVISORY UNTIL 6 PM MDT MONDAY WYZ002-015. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT MDT MONDAY NIGHT WYZ008-009. WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO MIDNIGHT MDT MONDAY NIGHT WYZ010. WINTER WEATHER ADVISORY UNTIL 3 PM MDT MONDAY WYZ003. && $$ UPDATE...WM SHORT TERM...LIPSON LONG TERM...KPL AVIATION...LIPSON FIRE WEATHER...KPL
AREA FORECAST DISCUSSION
NWS NEW YORK NY
435 AM EDT MON OCT 14 2013 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE THROUGH TUESDAY...REMAINING GENERALLY NORTH AND EAST OF THE WATERS. THIS HIGH PRESSURE AREA WEAKENS TUESDAY NIGHT INTO WEDNESDAY AS IT SHIFTS INTO THE CANADIAN MARITIMES. AS HIGH PRESSURE MOVES OUT TO SEA...WEAK LOW PRESSURE WILL DEVELOP OFF THE EAST COAST WHILE A FRONTAL SYSTEM APPROACHES FROM THE GREAT LAKES. THIS SYSTEMS COLD FRONT WILL MOVE ACROSS THE AREA LATE WEDNESDAY NIGHT OR THURSDAY MORNING. WAVES OF LOW PRESSURE ARE THEN FORECAST TO IMPACT THE AREA FRIDAY AND SATURDAY NIGHT. ANOTHER COLD FRONT MOVES THROUGH LATE SATURDAY NIGHT INTO SUNDAY MORNING. && .NEAR TERM /THROUGH TONIGHT/... PATCHY FOG WILL DISSIPATE WITH DIURNAL WARMING THIS MORNING ACROSS THE INTERIOR AND RURAL AREAS. HIGH PRESSURE REMAINS STRONG...ESPECIALLY NORTH AND EAST OF THE LOCAL REGION. ALOFT...A RIDGE WILL REMAIN DOMINANT WITH ITS BASE TO OUR SOUTH. A COLD FRONT ASSOCIATED WITH AN EQUIVALENT BAROTROPIC LOW IN EASTERN CANADA WILL WEAKEN THROUGH THE DAY WITH EASTWARD MOVEMENT. THE LOSS OF TEMPERATURE ADVECTIONS WILL CONTRIBUTE TO THE WEAKENING OF THIS SYSTEM AND INHERENTLY RESULTING IN THE FRONTOLYSIS. THE ONLY EFFECT OF THE FRONT WILL BE AN INCREASE IN THE MOISTURE IN THE 700 TO 850 MB COLUMN. THE LOWEST INVERSION AROUND 900MB GOING INTO THIS MORNING IS SHOWN TO MIX OUT BUT THE ONE AROUND 700 TO 800MB WILL REMAIN ALLOWING FOR MOISTURE TO COLLECT HERE. THIS IS WHERE CLOUDS WILL DEVELOP. THE NAM AND RUC BUFKITS INDICATE THIS POSSIBILITY BUT DIFFER ON THE TIMING WHILE THE GFS BUFKITS DOES NOT MOISTEN THE 700 TO 850MB LAYER BUT IS SLOWER TO MIX OUT THE LOWEST INVERSION AROUND 900MB WITH ITS CLOUDS THIS MORNING. HIGH PRESSURE WILL REMAIN DOMINANT THROUGH TONIGHT WITH A WEAK COLD FRONT APPROACHING FROM THE WEST. ONLY EXPECTING AN INCREASE IN CLOUDS FROM THIS PARTICULARLY TOWARDS AND DURING TONIGHT. THERE IS UNCERTAINTY ON EXACTLY HOW MUCH CLOUDS THERE WILL BE AND THE TIMING OF THE HIGHER CLOUD COVERAGE AND THIS IS ONE PARAMETER THAT COULD FLUCTUATE WITH SUBSEQUENT FORECASTS. THE RESULTING UNCERTAINTY WAS THE REASON WHY AN EQUAL BLEND OF MAV AND MET GUIDANCE WAS CHOSEN FOR HIGH TEMPERATURES TODAY...WHICH ARE FORECAST TO BE IN THE MID TO UPPER 60S FOR A MAJORITY OF THE REGION. THERE IS A LITTLE HIGHER CONFIDENCE ON MORE CLOUDS TONIGHT. HENCE...LOWS WERE PREFERRED WITH A 3/4 MET WARMER GUIDANCE TO 1/4 COOLER MAV GUIDANCE. WILL KEEP FORECAST ON THE SLOWER SIDE WITH PROGRESSION OF CLOUDS CONSIDERING THE LOWERING BOUNDARY LAYER FLOW AND LACK OF WINDS TO MIX DOWN. THIS WILL RESULT IN MORE CLOUDS FOR THE LATTER PORTION OF THE DAY AND NIGHTTIME. && .SHORT TERM /TUESDAY/... GOING WITH A WARMER DAY TUESDAY AS THE RIDGE SHIFTS EAST AND THERE IS MORE OF A SOUTHWEST FLOW ALOFT. THERE IS SOME PRETTY GOOD LOW LEVEL WARM ADVECTION TOO WITH THE SOUTHEAST FLOW AT 850MB VEERING TO THE SOUTHWEST FLOW AT 700MB. THE WINDS ARE SLIGHTLY MORE THAN THE PREVIOUS DAY. HIGH TEMPS WERE A BLEND OF THE WARMER MET 2/3 AND COOLER 1/3 MAV CONSIDERING THE WARM AIR ADVECTION. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... UPPER LEVEL RIDGE AXIS WILL SLIDE E OF THE AREA BY WED EVE WITH A TROUGH TRACKING TOWARDS THE AREA FROM THE GREAT LAKES/OHIO VALLEY REGION. THERE ARE TIMING DIFFERENCES WITH THE PROGRESSION OF THIS FIRST TROUGH WHICH HAS A RIPPLE EFFECT ON LATER PERIODS. THE GFS/GEFS MEAN IS FASTEST...FOLLOWED CLOSELY BY THE EC AND SREF...THEN THE NAM AND CMC AND LASTLY THE UKMET. HAVE STUCK WITH A MIDDLE OF THE ROAD SOLN...NAM/SREF BLEND UNTIL THIS IS BETTER RESOLVED. MEANWHILE...A BROAD UPPER LEVEL TROUGH WILL BE CARVED OUT THROUGH CENTRAL NOAM. A PROGRESSIVE PATTERN WILL DEVELOP ACROSS THE EASTERN US IN RESPONSE TO A TIGHT SW FLOW ALOFT. ANOTHER SHORTWAVE TROUGH MOVES THROUGH THE NORTHEAST THU NIGHT/FRI...WITH YET ANOTHER NEXT WEEKEND. AT THE SFC...HIGH PRES ENTRENCHED DOWN THE APPALACHIANS WILL WEAKEN AS AN INVERTED TROUGH DEVELOPS OFF THE EAST COAST. MODELS ARE VARYING WITH THE PRONUNCIATION OF THIS FEATURE AND HOW MUCH IT WILL IMPACT THE LOCAL AREA ON WED. FOR NOW HAVE SCHC POPS ACROSS THE EAST END ALTHOUGH SOME OF THIS SYSTEMS MOISTURE MAY BE INFUSED INTO AN APPROACHING COLD FRONT AND COULD PRODUCE SOME SHOWERS WELL OUT AHEAD OF IT. HAVE THE FRONT MOVING THROUGH LATE WED NIGHT/THU MORNING...CONSISTENT WITH A NAM/SREF BLEND AS STATED ABOVE. THE PROGRESSIVE FLOW DEVELOPING ALOFT WILL ALSO BE TRANSLATED TO THE SFC. WEAK HIGH PRES RETURNS IN THE WAKE OF THE FRONT WITH LOW PRES PASSING S OF LONG ISLAND THU NIGHT OR FRI. DRY CONDITIONS THEN RETURN AGAIN FRI NIGHT INTO SAT COURTESY OF HIGH PRES BUILDING TO OUR S...BUT A WAVE OF LOW PRES DEVELOPING OVER THE GULF COAST RIDES ALONG ANOTHER COLD FRONT MARCHING TOWARDS THE AREA NEXT WEEKEND. TEMPERATURES WILL START OFF 5 TO 10 DEGREES ABOVE NORMAL...BUT WILL GRADUALLY RETURN TO SEASONABLE LEVELS IN THE LOWER TO MID 60S DURING THE DAY AND 40S...AROUND 50 IN NYC...AT NIGHT NEXT WEEKEND. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL SETTLE OVER THE AREA TODAY. PATCHES OF MVFR CIGS CONTINUE...IMPACTING ABOUT HALF THE AREA. WILL CONTINUE TO MONITOR TRENDS. AMENDMENTS ARE LIKELY AS FORECASTING THESE CLOUDS REMAINS QUITE A CHALLENGE THIS MORNING. LIGHT E-NE FLOW SHOULD BECOME SE-S 5-10 KT BY AFTERNOON. IT IS UNCERTAIN EXACTLY WHERE THE HIGH PRESSURE RIDGE WILL BE ORIENTED BY LATE DAY...SO WIND DIRECTION FORECAST CONFIDENCE LOWERS LATE IN THE DAY. SPEEDS REMAIN LESS THAN 10 KT. SCT TO BROKEN CLOUDS 5 TO 10 KFT ARE ANTICIPATED LATE TODAY AND THROUGH THE EVENING AS AN APPROACHING FRONTAL BOUNDARY WEAKENS. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO S/SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KLGA FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KTEB FCSTER COMMENTS: POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KHPN FCSTER COMMENTS: POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KISP FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. OUTLOOK FOR 06Z TUE THROUGH FRI... .TONIGHT-TUE...VFR. .WED-FRI...MVFR CONDS POSSIBLE AT TIMES IN SCT SHOWERS. && .MARINE... SEAS ARE ON A SLOW DECLINE WITH WAVE HEIGHTS. HOWEVER...THERE IS STILL A 8 SEC EASTERLY SWELL WHICH WILL ENABLE FOR THE FURTHER DECREASES IN WAVE HEIGHT TO BE RATHER SLOW. WAVEWATCH IS ALSO NOW RUNNING A LITTLE LOW IN TERMS OF THE WAVE HEIGHT AT BUOY 44025. THE PRESSURE GRADIENT WILL WEAKEN CONSIDERABLY GOING INTO THE DAY SO THE SMALL CRAFT WAS CONVERTED TO ONE JUST FOR HAZARDOUS SEAS. GUSTS WILL BE LOWERING WITH CURRENT GUSTS ONLY UP TO 20 KT ON THE OCEAN. THE TIMING IS SUCH THAT THE OCEAN WEST OF MORICHES INLET WILL HAVE SMALL CRAFT CONDITIONS UNTIL 18Z WHILE EAST OF THERE...IT REMAINS UNTIL 16Z. THEREAFTER WITH WEAK PRESSURE GRADIENTS IN PLACE...SUB SCA CONDITIONS WILL BE FORECAST GOING INTO MONDAY NIGHT AND TUESDAY. A RELATIVELY WEAK FLOW WILL REMAIN ACROSS THE WATERS THROUGH THE END OF THE WEEK RESULTING IN SUB-SCA CONDS. && .HYDROLOGY... DRY WEATHER IS FORECAST THROUGH TUESDAY. GENERALLY BETWEEN 1/4 AND 1/2 INCH OF RAINFALL IS EXPECTED WITH THE COLD FRONTAL PASSAGE LATE WED NIGHT/THU MORNING. NO HYDROLOGIC ISSUES ARE ANTICIPATED WITH THIS. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ353-355. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON EDT TODAY FOR ANZ350. && $$ SYNOPSIS...24/JM NEAR TERM...JM SHORT TERM...JM LONG TERM...24 AVIATION...PW MARINE...24/JM HYDROLOGY...24/JM EQUIPMENT...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
404 AM EDT MON OCT 14 2013 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE THROUGH TUESDAY...REMAINING GENERALLY NORTH AND EAST OF THE WATERS. THIS HIGH PRESSURE AREA WEAKENS TUESDAY NIGHT INTO WEDNESDAY AS IT SHIFTS INTO THE CANADIAN MARITIMES. AS HIGH PRESSURE MOVES OUT TO SEA...WEAK LOW PRESSURE WILL DEVELOP OFF THE EAST COAST WHILE A FRONTAL SYSTEM APPROACHES FROM THE GREAT LAKES. THIS SYSTEMS COLD FRONT WILL MOVE ACROSS THE AREA LATE WEDNESDAY NIGHT OR THURSDAY MORNING. WAVES OF LOW PRESSURE ARE THEN FORECAST TO IMPACT THE AREA FRIDAY AND SATURDAY NIGHT. ANOTHER COLD FRONT MOVES THROUGH LATE SATURDAY NIGHT INTO SUNDAY MORNING. && .NEAR TERM /THROUGH TONIGHT/... PATCHY FOG WILL DISSIPATE WITH DIURNAL WARMING THIS MORNING ACROSS THE INTERIOR AND RURAL AREAS. HIGH PRESSURE REMAINS STRONG...ESPECIALLY NORTH AND EAST OF THE LOCAL REGION. ALOFT...A RIDGE WILL REMAIN DOMINANT WITH ITS BASE TO OUR SOUTH. A COLD FRONT ASSOCIATED WITH AN EQUIVALENT BAROTROPIC LOW IN EASTERN CANADA WILL WEAKEN THROUGH THE DAY WITH EASTWARD MOVEMENT. THE LOSS OF TEMPERATURE ADVECTIONS WILL CONTRIBUTE TO THE WEAKENING OF THIS SYSTEM AND INHERENTLY RESULTING IN THE FRONTOLYSIS. THE ONLY EFFECT OF THE FRONT WILL BE AN INCREASE IN THE MOISTURE IN THE 700 TO 850 MB COLUMN. THE LOWEST INVERSION AROUND 900MB GOING INTO THIS MORNING IS SHOWN TO MIX OUT BUT THE ONE AROUND 700 TO 800MB WILL REMAIN ALLOWING FOR MOISTURE TO COLLECT HERE. THIS IS WHERE CLOUDS WILL DEVELOP. THE NAM AND RUC BUFKITS INDICATE THIS POSSIBILITY BUT DIFFER ON THE TIMING WHILE THE GFS BUFKITS DOES NOT MOISTEN THE 700 TO 850MB LAYER BUT IS SLOWER TO MIX OUT THE LOWEST INVERSION AROUND 900MB WITH ITS CLOUDS THIS MORNING. HIGH PRESSURE WILL REMAIN DOMINANT THROUGH TONIGHT WITH A WEAK COLD FRONT APPROACHING FROM THE WEST. ONLY EXPECTING AN INCREASE IN CLOUDS FROM THIS PARTICULARLY TOWARDS AND DURING TONIGHT. THERE IS UNCERTAINTY ON EXACTLY HOW MUCH CLOUDS THERE WILL BE AND THE TIMING OF THE HIGHER CLOUD COVERAGE AND THIS IS ONE PARAMETER THAT COULD FLUCTUATE WITH SUBSEQUENT FORECASTS. THE RESULTING UNCERTAINTY WAS THE REASON WHY AN EQUAL BLEND OF MAV AND MET GUIDANCE WAS CHOSEN FOR HIGH TEMPERATURES TODAY...WHICH ARE FORECAST TO BE IN THE MID TO UPPER 60S FOR A MAJORITY OF THE REGION. THERE IS A LITTLE HIGHER CONFIDENCE ON MORE CLOUDS TONIGHT. HENCE...LOWS WERE PREFERRED WITH A 3/4 MET WARMER GUIDANCE TO 1/4 COOLER MAV GUIDANCE. WILL KEEP FORECAST ON THE SLOWER SIDE WITH PROGRESSION OF CLOUDS CONSIDERING THE LOWERING BOUNDARY LAYER FLOW AND LACK OF WINDS TO MIX DOWN. THIS WILL RESULT IN MORE CLOUDS FOR THE LATTER PORTION OF THE DAY AND NIGHTTIME. && .SHORT TERM /TUESDAY/... GOING WITH A WARMER DAY TUESDAY AS THE RIDGE SHIFTS EAST AND THERE IS MORE OF A SOUTHWEST FLOW ALOFT. THERE IS SOME PRETTY GOOD LOW LEVEL WARM ADVECTION TOO WITH THE SOUTHEAST FLOW AT 850MB VEERING TO THE SOUTHWEST FLOW AT 700MB. THE WINDS ARE SLIGHTLY MORE THAN THE PREVIOUS DAY. HIGH TEMPS WERE A BLEND OF THE WARMER MET 2/3 AND COOLER 1/3 MAV CONSIDERING THE WARM AIR ADVECTION. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... UPPER RIDGE OVER THE EASTERN COAST MOVES OFFSHORE TUESDAY INTO TUESDAY NIGHT AS DIGGING TROUGH FROM CENTRAL CANADA DIGS INTO THE UPPER MIDWEST AND MOVES THROUGH THE GREAT LAKES REGION. SURFACE HIGH PRESSURE MOVES OFF THE NEW ENGLAND COAST WITH THE HIGH REMAINING EAST OF THE APPALACHIANS. WITH THE SURFACE LOW WELL TO THE WEST TUESDAY NIGHT INTO WEDNESDAY...AND WARM ADVECTION RATHER WEAK...NOT EXPECTING THE WARM FRONT TO MOVE THROUGH UNTIL DURING THE DAY WEDNESDAY. SOME WEAK OVERRUNNING PRECIPITATION WILL BE POSSIBLE IN ASSOCIATION WITH WEAK ISENTROPIC LIFT. LEANED TOWARD THE NAM AND ECMWF AS THE GFS BECOMES AN OUTLIER BY WEDNESDAY...BECOMING TOO PROGRESSIVE AND WEAKER WITH THE SYSTEM. EVEN THE LIFT WITH THE COLD FRONT IS WEAK AND WILL KEEP LOW END CHANCE POPS WEDNESDAY NIGHT INTO THURSDAY. BROAD UPPER TROUGH REMAINS ACROSS CENTRAL CANADA AND INTO THE NORTHEAST WITH A SERIES OF SHORTWAVES ROTATING THROUGH. FLOW REMAINS PROGRESSIVE THURSDAY THROUGH THE UPCOMING WEEKEND...WITH ANOTHER COLD FRONT COMING THROUGH THE REGION SATURDAY INTO SUNDAY. WITH THE PROGRESSIVE FLOW FRONTAL TIMING TOUGH TO DETERMINE AT THIS TIME. FOR WEDNESDAY THROUGH SUNDAY USED A BLEND OF THE WPC GUIDANCE AND THE ECMWF. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL SETTLE OVER THE AREA TODAY. PATCHES OF MVFR CIGS CONTINUE...IMPACTING ABOUT HALF THE AREA. WILL CONTINUE TO MONITOR TRENDS. AMENDMENTS ARE LIKELY AS FORECASTING THESE CLOUDS REMAINS QUITE A CHALLENGE THIS MORNING. LIGHT E-NE FLOW SHOULD BECOME SE-S 5-10 KT BY AFTERNOON. IT IS UNCERTAIN EXACTLY WHERE THE HIGH PRESSURE RIDGE WILL BE ORIENTED BY LATE DAY...SO WIND DIRECTION FORECAST CONFIDENCE LOWERS LATE IN THE DAY. SPEEDS REMAIN LESS THAN 10 KT. SCT TO BROKEN CLOUDS 5 TO 10 KFT ARE ANTICIPATED LATE TODAY AND THROUGH THE EVENING AS AN APPROACHING FRONTAL BOUNDARY WEAKENS. ...NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO S/SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KLGA FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KTEB FCSTER COMMENTS: POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KHPN FCSTER COMMENTS: POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KISP FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. OUTLOOK FOR 06Z TUE THROUGH FRI... .TONIGHT-TUE...VFR. .WED-FRI...MVFR CONDS POSSIBLE AT TIMES IN SCT SHOWERS. && .MARINE... SEAS ARE ON A SLOW DECLINE WITH WAVE HEIGHTS. HOWEVER...THERE IS STILL A 8 SEC EASTERLY SWELL WHICH WILL ENABLE FOR THE FURTHER DECREASES IN WAVE HEIGHT TO BE RATHER SLOW. WAVEWATCH IS ALSO NOW RUNNING A LITTLE LOW IN TERMS OF THE WAVE HEIGHT AT BUOY 44025. THE PRESSURE GRADIENT WILL WEAKEN CONSIDERABLY GOING INTO THE DAY SO THE SMALL CRAFT WAS CONVERTED TO ONE JUST FOR HAZARDOUS SEAS. GUSTS WILL BE LOWERING WITH CURRENT GUSTS ONLY UP TO 20 KT ON THE OCEAN. THE TIMING IS SUCH THAT THE OCEAN WEST OF MORICHES INLET WILL HAVE SMALL CRAFT CONDITIONS UNTIL 18Z WHILE EAST OF THERE...IT REMAINS UNTIL 16Z. THEREAFTER WITH WEAK PRESSURE GRADIENTS IN PLACE...SUB SCA CONDITIONS WILL BE FORECAST GOING INTO MONDAY NIGHT AND TUESDAY. && .HYDROLOGY... DRY WEATHER IS FORECAST THROUGH TUESDAY. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ353-355. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON EDT TODAY FOR ANZ350. && $$ SYNOPSIS...24/JM NEAR TERM...JM SHORT TERM...JM LONG TERM...24 AVIATION...PW MARINE...24/JM HYDROLOGY...24/JM EQUIPMENT...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1256 AM CDT MON OCT 14 2013 .DISCUSSION... 734 PM CDT TEMPERATURES ARE ALREADY DROPPING MUCH FASTER THAN FORECAST SO LOWERED MIN TEMPS FOR TONIGHT AND ADJUSTED TEMP TRENDS. IN ADDITION EXPANDED THE FROST ADVISORY TO INCLUDE THE FAR SOUTHERN COUNTIES IN IL AND LAKE COUNTY IL. PARTS OF INDIANA MAY SEE AREAS OF FROST TONIGHT...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE ANY INDIANA COUNTIES IN THE FROST ADVISORY. LASTLY...LOWERED SKY COVER ACROSS THE LAKE... NW INDIANA...AND NE ILLINOIS TOMORROW AS THINKING LIGHT WINDS AND THE VERY DRY AIR OVERHEAD WILL LIMIT THE CLOUD COVER. OTHERWISE THE CURRENT FORECAST IS ON TRACK. JEE //PREV DISCUSSION... 305 PM CDT THE CHALLENGES WITH THE FORECAST ARE FROST POTENTIAL TONIGHT...FOLLOWED BY MORNING CLOUDS OFF THE LAKE ON MONDAY AND THEN RAIN CHANCES TUESDAY. FINALLY THE SUBSEQUENT NOTEWORTHY COOL DOWN INTO NEXT WEEK WILL BECOME A GREATER FORECAST CHALLENGE AS THIS WEEK PROGRESSES. SYNOPSIS...EXPANSIVE 1030MB CANADIAN HIGH PRESSURE IS IN PLACE ACROSS THE UPPER MIDWEST AND WILL SHIFT DIRECTLY OVER THE AREA BY EVENING. COOL BUT MORE SEASONAL 850MB TEMPS WERE OBSERVED ACROSS THE AREA THIS MORNING...INCLUDING +3C AT DVN. ALMOST ALL 12Z GUIDANCE INITIALIZED TOO MILD WITH THIS LOW-LEVEL COOL AIR. THAT MAY BE ONE REASON WHY MOST OF THE GUIDANCE SOLUTIONS FOR TEMPS TONIGHT ARE LIKELY TOO WARM. TONIGHT...SATELLITE REVEALS THE ONLY CLOUDS IN THE IMMEDIATE REGION ARE ACROSS NORTHERN LAKE MI...AND THESE ARE IN PLACE THANKS TO THE COLD AIR MASS MOVING OVER THE STILL MILD WATERS. AS THE HIGH DOES MOVE OVER THE AREA...850-1000MB LOW WILL TURN MORE NORTHERLY AND THEN NORTHEASTERLY. SPEEDS WILL DROP BUT ARE LIKELY ENOUGH TO ADVECT LAKE-INDUCED STEEP LAPSE RATES AND SATURATION ON TOP OF THIS INDICATIVE OF STRATOCU INTO FAR NW IN AND THEN FAR NE IL AFTER MIDNIGHT. NAM AND LOCAL ARW SOUNDINGS AND LOW-LEVEL RH FIELDS ARE IN AGREEMENT TO THIS SOLUTIONS...ALONG WITH SPC WRF COLUMN CONDENSATE WHICH SEEMS TO DO WELL WITH STRATOCU IN THESE SITUATIONS. THIS WILL LIKELY SLOW OR EVEN HALT THE TEMPERATURE DROP LATE TONIGHT IN DOWNTOWN CHICAGO AND OTHER LAKE ADJACENT AREAS. FOR THE REMAINDER OF THE CWA...A PICTURE PERFECT RADIATIONAL COOLING EVENING AND OVERNIGHT IS SHAPING UP AS THE ATMOSPHERE SHOULD DECOUPLE BY EARLY TO MID EVE. HAD ADJUSTED THE HOURLY TEMPERATURE TREND TO REFLECT QUICK COOLING AFTER DARK...AND FOR MINS HAVE CONSIDERED LAST NIGHTS TEMPS STRONGLY AS A BASELINE AS OPPOSED TO ANY GUIDANCE SOURCE. THERE IS LITTLE REASON FOR OUTLYING AREAS TO BE WARMER THAN THEY WERE THIS MORNING...AND CURRENT SURFACE DEW POINTS LEAN THAT ROUTE AS WELL INDICATING THE BOUNDARY LAYER IS WELL MIXED TODAY. SO EXPECTING WIDESPREAD 32 TO 35 ACROSS NORTH CENTRAL IL WITH MID TO UPPER 30S ELSEWHERE IN OUTLYING AREAS. CONSIDERING COCORAHS OBSERVER COMMENTS THIS MORNING REPORTING PATCHY FROST...WOULD EXPECT CLOSER TO A WIDESPREAD FROST IN NORTH CENTRAL IL. CONSIDERING THE MILD NIGHT AS OF RECENT...WE HAVE GONE AHEAD AND COLLABORATED A FROST ADVISORY FOR LATE TONIGHT...THE FIRST SUCH ADVISORY OF THE SEASON. MONDAY...THE HIGH WILL REMAIN IN CONTROL ON COLUMBUS DAY. THE LAKE EFFECT CLOUDS ARE ANTICIPATED TO LINGER IN NORTHEAST IL...POSSIBLY AS FAR WEST AS NORTH CENTRAL IL...BUT AMOUNT OF COVERAGE IS LOW CONFIDENCE. THE CLOUD DEPTH LOOKS TO BE AT OR UNDER 3K FT AT MOST OVER THE LAKE SO ANY STRATOCU MAY BEGIN TO THIN QUICKLY BY LATE MORNING. MIXING LOOKS TO BE TO 875MB...AND THAT SHOULD SUPPORT 60S ACROSS THE AREA. TUESDAY AND WEDNESDAY...A PRONOUNCED UPPER TROUGH ACROSS UT/NV WILL SHIFT ENE INTO THE UPPER MIDWEST DURING THIS PERIOD...AND THIS WILL BE THE FIRST OF MULTIPLE UPPER WAVES EVOLVING EASTWARD ACROSS NORTH AMERICA DURING THE MIDDLE OF THIS WEEK. TOGETHER THESE WILL CARVE OUT A LONG WAVE TROUGH OVER THE CENTRAL PART OF THE CONTINENT...EXTENDING INTO THE MIDWEST BY WEEKS END. THIS FIRST WAVE ON TUESDAY LOOKS TO BRING THE BEST CHANCE OF RAIN TO THE AREA AS PRONOUNCED HEIGHT FALLS MOVE ACROSS THE AREA ALONG WITH DYNAMIC SUPPORT FOR ENHANCED LIFT AHEAD OF THE SYSTEM COOL FRONT. THE GFS REMAINS THE QUICKEST SOLUTION WITH THIS...BUT NOT BY MUCH AT ALL. THE MEAN OF THE SOLUTIONS PAINTS THE MORNING AND EARLY AFTERNOON WILL BE THE BEST CHANCE FOR WIDESPREAD SHOWERS AS THE MOISTURE TRANSPORT MAX POINTS INTO THE REGION. AS THE COLD FRONT SHIFTS EASTWARD THROUGH THE AREA LIKELY DURING TUESDAY AFTERNOON...THIS MAY PRESENT A BETTER CHANCE FOR THUNDER. INSTABILITY RETURN LOOKS TO BE VERY MODEST AT BEST...ESPECIALLY IF THERE IS MORNING WIDESPREAD CLOUDS AND RAIN. THE DRY SLOT STILL LOOKS TO EVOLVE OVER TUE NIGHT WITH ANY PRECIP LIKELY TO BE LIGHT AT THAT POINT. COLD AIR ADVECTION WRAPS AROUND THIS SYSTEM AND PREVAILS ON WED WITH HIGHS 10 TO 15 DEGREES COOLER THAN TUE. SMALL CHANCES FOR SHOWERS ARE IN WEDNESDAY AS THE COLD CORE SYSTEM MOVES OVERHEAD. THURSDAY AND BEYOND...THE SUCCESSIVE SHORT WAVE TROUGHS WILL LEAD TO PROGRESSIVE THICKNESS FALLS AND COOLING TEMPS. THE 850 0C ISOTHERM DROPS SOUTH INTO THE AREA ON FRIDAY IN THE GFS/EC MEAN SOLUTION WITH AN ASSOCIATED COLD FRONT. THIS SETS THE STAGE FOR THE FIRST POSSIBLE WIDESPREAD FREEZE ON FRIDAY OR SATURDAY NIGHT IF INDEED HIGH PRESSURE FOLLOWS WHICH IT LOOKS TO. MTF && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * POTENTIAL FOR A PERIOD OF HIGH-END MVFR CIGS VERY LATE TONIGHT/EARLY THIS MORNING. * LIGHT NORTH/VARIABLE WIND OVERNIGHT BECOMING EAST THIS MORNING. MDB //DISCUSSION...UPDATED 06Z... HIGH PRESSURE CENTERED ACROSS WISCONSIN WILL SHIFT EASTWARD THROUGH TODAY. THE WEAK PRESSURE GRADIENT HAS ALLOWED WINDS TO BECOME CALM/LIGHT AND VARIABLE ACROSS MOST OF THE AREA. A WEAK LAND BREEZE IS SETTING UP BASED ON OBS NEAR LAKE MICHIGAN WHICH IS PROVIDING LIGHT NORTH TO NORTHWEST WINDS AT ORD/MDW. SKIES ARE CLEAR AWAY FROM LAKE MICHIGAN BUT LAKE EFFECT STRATUS HAS BEEN DEVELOPING OVER THE SOUTH END OF THE LAKE. AT THIS POINT BASES LOOK TO BE IN THE 3000-4000 FT RANGE BUT MAY SEE SOME LOWERING AS COVERAGE INCREASES AND LAND AREAS COOL FURTHER. THESE CLOUDS ARE ALSO EXPECTED TO SPREAD INLAND OVER THE CHICAGO METRO TOWARD MORNING. WILL CONTINUE WITH SCATTERED LOW END VFR CLOUD MENTION AT ORD/MDW FOR NOW BUT BKN PERIODS ARE POSSIBLE FOR SEVERAL HOURS LATE THIS MORNING. WILL CARRY BKN LOW END VFR CIGS AT GYY. ONCE THE SUN RISES THE LAND BREEZE WILL FADE AND A LARGER SCALE LIGHT EAST TO EAST-SOUTHEAST WIND WILL TAKE OVER ACROSS THE AREA. EXPECT THAT THE LAKE CLOUD COVER WILL DISSIPATE WITH TIME INTO LATE AFTERNOON. WINDS WILL TURN SOUTHEASTERLY THIS EVENING WITH STEADY OR EVEN INCREASING SPEEDS TONIGHT AS LOW PRESSURE MOVES NORTHEAST FROM THE CENTRAL PLAINS. MDB //ORD AND MDW CONFIDENCE...UPDATED 06Z... * MEDIUM CONFIDENCE IN SCT-BKN CLOUDS ARRIVING LATE TONIGHT/EARLY THIS MORNING...LOW CONFIDENCE IF THEY WILL BE MVFR. * HIGH CONFIDENCE IN WIND TRENDS. MDB //OUTLOOK FOR ORD/MDW FOR 12Z TUESDAY-12Z SUNDAY...UPDATED 00Z... TUESDAY...SHRA/FEW TSRA LIKELY. MVFR POSSIBLE. WEDNESDAY...CHANCE SHRA. MVFR POSSIBLE. THURSDAY...VFR. FRIDAY AND SATURDAY...SLIGHT CHANCE SHRA. MAINLY VFR. RATZER && .MARINE... 225 PM CDT WINDS WILL VEER TO OUT OF THE NORTH AND NORTHEAST AND DIMINISH TONIGHT AS HIGH PRESSURE CENTERED OVER NORTHWEST IOWA AT MID AFTERNOON BUILDS ACROSS THE UPPER MIDWEST AND UPPER GREAT LAKES DURING THE NIGHT. AS THE HIGH CONTINUES ON ACROSS ONTARIO TO SOUTHERN QUEBEC MONDAY AND MONDAY NIGHT LOW PRESSURE WILL BE ORGANIZING OVER THE CENTRAL HIGH PLAINS AND DEEPENING AS IT MOVES NORTHEASTWARD TO SOUTHERN MINNESOTA. WITH THE WESTERN GREAT LAKES BETWEEN THE DEPARTING HIGH AND THE APPROACHING STRENGTHENING LOW WINDS ON LAKE MICHIGAN INCREASE TO MODERATE AND FRESH BREEZES WHILE VEERING TO OUT OF THE SOUTHEAST AND SOUTH DURING MONDAY NIGHT AND TUESDAY. THE LOW MOVES ACROSS NORTHERN WISCONSIN AND THE EASTERN UPPER PENINSULA OF MICHIGAN TUESDAY NIGHT AND WEDNESDAY. AS IT DOES IT WILL PUSH A COLD FRONT EASTWARD ACROSS LAKE MICHIGAN. TRS && .LOT WATCHES/WARNINGS/ADVISORIES... IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010- ILZ011-ILZ012-ILZ019-ILZ020-ILZ021-ILZ023-ILZ032-ILZ033- ILZ039 UNTIL 8 AM MONDAY. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1106 PM CDT Sun Oct 13 2013 .DISCUSSION... ISSUED 815 PM CDT Sun Oct 13 2013 In the process of updating the ZFP this evening to include a Frost Advisory for areas mainly north of a Lewistown to Bloomington line. Early morning temperatures are expected to drop into the middle 30s across the north for a time Monday morning allowing frost to form, especially away from the metropolitan areas of Peoria and Bloomington. Further south, have added some patchy frost for early Monday morning. Early evening temperatures were dropping off rapidly with readings already in the middle 40s across the far north (Galesburg and Lacon). The latest HRRR model suggests the threat for a more prolonged period of calm winds north of I-74 in the 09z-12z time frame as the center of the high will shift just north of our area. Early evening dew points have settled into the lower to middle 30s and that usually gives us a good idea where the early morning low may dip to with this type of radiational cooling setup, especially in low lying areas and in locations away from the city. Have edged the overnight lows down a degree or two further south and as mentioned above, added some patchy frost as well, but the best threat for our first frost of the season will be mainly north of I-74 early Monday morning. The updated zones should be out by 0145z. && .AVIATION... ISSUED 1105 PM CDT Sun Oct 13 2013 VFR conditions are expected through this forecast period (06z Tue). High pressure will drift well to our north tonight into Monday morning allowing a light northeast flow to prevail. A clear sky can be expected into the early afternoon hours of Monday before high level clouds increase ahead of the next weather system slated to affect our area just after this forecast period. Surface winds on Monday will veer slightly into an east-southeast direction at around 10 kts. Smith && .PREV DISCUSSION... ISSUED 249 PM CDT Sun Oct 13 2013 After collaboration with DVN and LOT, have added patchy frost to areas across the northwest forecast area and made some minor adjustments to other grids for late tonight and early Monday morning. Do not expect frost to be widespread enough to warrant an advisory, but wind protected areas may see some patchy frost. && .ILX WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY from 3 AM to 8 AM CDT Monday FOR ILZ027>031- 036>038. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
403 AM CDT Mon Oct 14 2013 .SHORT TERM...(Today and Tonight) Issued at 403 AM CDT MON OCT 14 2013 Confidence on the specifics of when and where best coverage of precipitation will be over the next 24 hours is not high, but the overall setup is for a widespread wet event over much of the Central Plains. 00Z upper jet structure showed southern branch from central Baja into Kansas with northern branch south and east around the Great Basin upper low then northeast into the Four Corners, and this will push east through tonight with persistent diffluence over Kansas resulting. Deep moisture will steadily increase with stronger mid level flow initially leading to better isentropic lift there (ongoing in central portions of the state) and then somewhat lower as the day progresses and 850 mb winds increase to near 60 kt around 00Z. Elevated creeps up as well for an increasing thunder concern pushing east with time. Have generally indicated the most likely wet periods from mid morning through early evening from west to east, close to the WRF-ARW and recent HRRR runs which seem to be handling the overnight convection the best. They are also similar with surface-based storms breaking out in the KHLC vicinity in the late afternoon hours as the mid level dry slot works northeast and cold front surges east. With plenty of shear, CAPE will be the main limiting factor with this activity maintaining itself through north central Kansas, but at least minor concern for severe hail and wind potential exist in western areas. Cold front sweeps through overnight with clearing and drying taking over. High temperature details are also difficult with onset and duration of daytime precip and continued late-day south winds coinciding with some potential dry periods in the west possibly leading to max values around 0Z. .LONG TERM...(Tuesday through Sunday) Issued at 403 AM CDT MON OCT 14 2013 Drier air will move into eastern Kansas in the wake of the frontal boundary and upper level system on Tuesday. Surface high pressure will build into eastern Kansas Tuesday night and Wednesday keeping winds rather light and temperatures below normal. GFS and ECMWF move an upper trough across the plains Wednesday and Wednesday night. Forecast soundings show dry air in the low and mid levels will be present keeping chances of any measurable precipitation to the south of the CWA. Cannot rule out a few sprinkles south of I-35 though. Models continue to offer differing solutions for Friday through the weekend. The ECMWF has been inconsistent while the GFS has been more consistent on a run to run basis. The ECMWF is much sharper and further south with the mid level trough while the GFS maintains a ridge in the eastern Pacific and northwest flow across the Plains with a broad upper low over Ontario into the Ohio Valley through the weekend. However the ECMWF brings another shortwave trough across Kansas Saturday. Given the differences in the models and limited moisture availability, will go with a dry forecast at this time and will wait and see what later model runs provide. Highs will mainly be in the 60s with lows in the 30s and 40s. && .AVIATION...(For the 06Z TAFs through 06Z Monday Night) Issued at 1149 PM CDT SUN OCT 13 2013 Not much change to prior fcst as moisture surges northward across the terminals overnight with stratocu deck thickening/lowering to around 3500 feet by 11-13z time frame with some convection in the vcnty. As the main axis of deeper moisture advects northward and large scale lifts increases, showers and thunderstorms will increase west to east across the terminals aft 16z with lowering cigs to mvfr thru 00z. East southeasterly winds generally 5 to 8kts will increase aft 12z with gusts aoa 20kts through the end of the fcst period...although a gradual veering and decrease in speeds may occur aft 02z/15 as front approaches. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...53 AVIATION...63
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
204 AM EDT MON OCT 14 2013 .SYNOPSIS... STRONG HIGH PRESSURE WILL SLOWLY PUSH OFF THE NEW ENGLAND COAST THROUGH TUESDAY...AS A TROUGH OF LOW PRESSURE REMAINS ANCHORED OFF THE SOUTHEAST COAST. AS A RESULT...NORTHEAST WINDS WILL CONTINUE TO BRING MAINLY CLOUDY AND DAMP CONDITIONS INTO MONDAY MORNING. A SLOW DRYING TREND IS EXPECTED MONDAY AFTERNOON THROUGH TUESDAY...AS A PORTION OF THE HIGH RIDGES SOUTH INTO THE NORTHERN MID ATLANTIC REGION. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST LATE WEDNESDAY INTO THURSDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE LATEST SURFACE ANALYSIS SHOWS A 1015MB LOW PRESSURE CENTER OFF THE NC/SC COAST WITH A STEADY PRESSURE TENDENCY. MEANWHILE...A ~1030MB SFC HIGH PRESSURE ANCHORED ALONG THE COAST OF SOUTHERN COAST OF MAINE IS SLOWLY BUILDING SSW INTO THE MID ATLANTIC REVEALED BY +2MB/3HR PRESSURE RISES ACROSS THE REGION. ALOFT...A MID-LEVEL LOW CONTINUES TO LINGER OFF THE COAST ABOVE THE SURFACE REFLECTION OF THE LOW. THE PRIMARY MOIST FRONTAL BAND (DOWNSTREAM OF THE LOW) IS WELL OFF THE COAST OVER THE SUBTROPICAL WESTERN ATLANTIC. HOWEVER...A MOIST AIRSTREAM CONTINUES TO FLOW WESTWARD TOWARD THE LOCAL AREA...WITH IR SATELLITE ENHANCEMENT SUGGESTING SOME LIFT WITHIN THIS AIRSTREAM. THE LATEST RUC BRINGS THIS LIFT INTO NE NC/FAR SE VA LATE TONIGHT INTO EARLY MONDAY...SO A PERIOD OF LIKELY AND CATEGORICAL RAIN HAS BEEN INTRODUCED. OTHERWISE...AREAS OF LIGHT RAIN AND DRIZZLE SHOULD PERSIST OVERNIGHT MAINLY ACROSS SOUTHERN AND WESTERN PORTIONS. WITH NE FLOW REMAINING BREEZY...LOWS WILL AVG 60-65 OVER SE VA/NE NC MID- UPPER 50S NW. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/... MON WILL GENLY BEGIN CLOUDY AND DAMP ONCE AGAIN...BUT SLOW DRYING FROM THE NNE WILL BEGIN THROUGH THE DAY. MDL TIME SECTIONS (WHICH GENERALLY HOLD ONTO MSTR UP TO 3-4K FT) WILL HANG ONTO CLDY/DAMP CONDS WELL THROUGH THE DAY MON ACRS SRN VA/NE NC...WHILE SKIES BECOME PARTLY SUNNY ACRS THE NORTH. HIGHS GENLY CLOSE TO 70 F THROUGHOUT. WK REFLECTION OF LO PRES LINGERS INVOF CSTL NC...AND SFC HI PRES NNE OF THE RGN WKNS MON NGT THROUGH TUE. THEREFORE...CONFIDENCE IN PRONOUNCED CLRG...ESP ACRS SRN VA/NE NC...RMNG QUITE LOW. THERE IS NO MECHANISM TO SCOUR OUT THE LO LVL MSTR...AND CONCERNED THAT WHILE THERE WILL LIKELY BE SOME PROGRESS (OR TREND) TOWARD CLRG ERY IN THE WK...LO CLDS WILL BE DIFFICULT TO DISLODGE (OR EVEN IF THERE IS CLRG ON MON IN SOME PLACES - CLDS RETURN MON NGT AND/OR TUE). RA CHCS XPCD TO BE LWR FOR TUE...HWVR...WOULD NOT RULE OUT AT LEAST PTCHY DZ CONTG ACRS THE SE. INCREASING CLOUDINESS FROM THE W TUE NIGHT/WED AS THE SFC RIDGE WEAKENS. WILL SEE PARTLY TO MOSTLY CLOUDY SKIES WED W/ HIGHS 70-75. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... WSW FLOW ALOFT BEGINS TO INCREASE AHEAD OF THE NEXT SYSTEM PUSHING FROM THE UPPER MIDWEST TO THE GREAT LAKES ON WED CAUSING THE SFC RIDGING ASSOCIATED WITH HIGH PRESSURE OFF THE NEW ENGLAND COAST TO WEAKEN. LATEST ECMWF/GFS IN GOOD AGREEMENT THROUGH EARLY FRI SHOWING POTENTIAL FOR MOISTURE AND CLOUDS AS COLD FRONT APPROACHES THE AREA FROM THE WEST. DIFFERENCES BETWEEN THE MODELS BEGIN TO ARISE FRI NIGHT AS GFS SWEEPS THE FRONT THROUGH THE AREA WHILE THE ECMWF STALLS THE FRONT OVER THE AREA. TRENDED TOWARDS THE ECMWF DUE TO TRENDS LATELY IN WHICH COLD FRONTS STRUGGLE TO BE ABLE TO PUSH THEIR WAY COMPLETELY THROUGH THE AREA AND OFF THE COAST. WITH THE FRONT STALLING AROUND THE AREA EXPECT WARMER TEMPS BUT WITH A CLOUDIER/WETTER FORECAST. STRONGEST DYNAMICS STAY WELL TO OUR NW SO WILL ONLY CARRY A 30% POP THU THROUGH FRI MORNING FOR NOW. TEMPS WILL BE CLOSE TO AVG BY DAY WITH HIGHS MAINLY 70-75 AND A BIT ABOVE AVG AT NIGHT WITH LOWS IN THE LOW 50S TO AROUND 60 SE COAST. BY SAT...ECMWF SHOWS ANOTHER FRONT APPROACHING FROM THE WEST AS THE MID LEVEL FLOW REMAINS FROM THE SW AGAIN BRINGING THE POSSIBILITY FOR ANOTHER ROUND OF PRECIP. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... STRONG NE FLOW WILL CONTINUE OVER THE REGION THROUGH TODAY...DUE TO COMBINATION OF STRONG HI PRES BLDNG OVR NEW ENGLAND AND A WEAK AREA OF LO PRES OFF THE MID ATLC AND SE COAST. MAINLY IFR/MVFR CIGS AND OCNL -RA/-DZ WILL PERSIST OVR THE TAF SITES THRU THIS MORNG. BUFKIT SOUNDINGS INDICATE IMPROVEMENT TO MVFR/VFR CONDITIONS THIS AFTN INTO THIS EVENG. BUT...IFR CONDITIONS (FOG OR STRATUS) WILL LIKELY RETURN AGAIN LATE TNGT INTO TUE MORNG...DUE TO ANY CLEARING...CONTINUED WET GROUND...AND LIGHTER NE WINDS. && .MARINE... SOLID SCA CONDITIONS CONTINUE AS TIGHT PRESSURE GRADIENT REMAINS OVER THE WATERS. STRONG 1031 MB SFC HIGH PRESSURE (+1 STD DEV MSLP) WILL CONTINUE TO BUILD OVER THE NE STATES AS THE PERSISTENT SFC LOW OF THE PAST SEVERAL DAYS WILL DRIFT SWD...LOCATING JUST OFF THE SE NC COAST. NE WINDS HAVE INCREASED AS THE STRONGEST LOW LEVEL WINDS TRANSITION SWD OVER THE WATERS. GOOD LOW LEVEL GRADIENT WILL MIX THESE STRONGER WINDS TO THE WATER...WITH GUSTS UP TO 28 KT ALREADY OBSERVED OVER THE CNTRL BAY AND NRN COASTAL ZONES. HIGHER PLATFORMS...INCLUDING THE CBBT...HAVE REACHED 30 KT. STRONG WINDS HAVE BUILT WAVES TO 4-5 FT IN THE BAY AND 6 TO 10 FT OVER THE COASTAL WATERS. HIGH PRESSURE WILL SETTLE OFF THE NE COAST MON AS A WEAK COASTAL TROUGH REMAINS OFF THE COAST. GRADIENT WILL BEGIN TO RELAX OVER THE NRN WATERS...BUT SCA CONDITIONS WILL CONTINUE OVER THE SRN BAY AS NE WINDS REMAIN 15 TO 20 KT AND WAVES 3-4 FT. SEAS WILL SUBSIDE TO NEAR 5-6 FT OVER THE NRN COASTAL ZONES...AS SEAS IN THE SRN ZONES BUILD TO 6-9 FT. HIGH PRESSURE WILL MOVE EWD AWAY FROM THE NE COAST TUES...ALLOWING THE GRADIENT TO RELAX OVER THE WATERS AND NE WINDS TO FINALLY FALL BELOW SCA SPEEDS. HOWEVER...PERSISTENT NE WINDS WILL KEEP SEAS HIGH (5-6 FT) AND SCA HEADLINES THRU LATE TUES. WILL ALSO KEEP SCA HEADLINES IN THE MOUTH OF THE BAY AS 4 FT WAVES ARE FORECAST. HIGH SEAS WILL LIKELY CONTINUE INTO WEDS...BUT CONDITIONS OVER THE BAY/RIVER/SOUND WILL BE FAVORABLE WITH ELY WINDS GENERALLY BELOW 10 KT. A COLD FRONT WILL APPROACH THE WATERS WEDS NIGHT-THURS MORNING. && .TIDES/COASTAL FLOODING... STRONG NE WINDS WILL CONTINUE TO RESULT IN 1 TO 1.5 FOOT (APPROACHING 2 FT ALONG THE COASTAL ERN SHORE DUE TO NEAR GALE FORCE WINDS) TIDAL ANOMALIES THROUGH THE OVERNIGHT. HAVE EXTENDED ALL HEADLINES THROUGH MONDAY MORNINGS HIGH TIDE CYCLES AS MINOR COASTAL FLOODING IS EITHER IMMINENT...OR CONFIDENCE OF REACHING MINOR FLOOD LEVELS IS HIGH. STRONG NE WINDS OVER THE BAY MAY PUSH WATER LEVELS TO NEAR MODERATE THRESHOLDS AT WINDMILL POINT AND THE LOWER NRN NECK MONDAY MORNING. ADVISORY LEVEL FLOODING IS POSSIBLE AGAIN DURING MONDAYS HIGH TIDE CYCLES. SEE CFWAKQ FOR MORE SITE- SPECIFIC TIDAL INFORMATION. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...COASTAL FLOOD ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MDZ024- 025. COASTAL FLOOD ADVISORY UNTIL 3 PM EDT THIS AFTERNOON FOR MDZ021>023. NC...NONE. VA...COASTAL FLOOD ADVISORY UNTIL NOON EDT TODAY FOR VAZ075>078-081- 082-084>086-089>091-093-094-096-097. COASTAL FLOOD ADVISORY UNTIL 8 AM EDT THIS MORNING FOR VAZ095- 098. COASTAL FLOOD ADVISORY UNTIL 10 AM EDT THIS MORNING FOR VAZ099- 100. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT TUESDAY FOR ANZ634-650-652- 654-656-658. SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ630-631-636- 637. SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ635. SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ632. SMALL CRAFT ADVISORY UNTIL NOON EDT TUESDAY FOR ANZ633. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ638. && $$ SYNOPSIS...LKB NEAR TERM...AJZ/LKB SHORT TERM...ALB/LKB LONG TERM...DAP AVIATION...TMG MARINE...SAM TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
527 AM EDT MON OCT 14 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 527 AM EDT MON OCT 14 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED MID LEVEL LOW LIFTING NE ACROSS HUDSON BAY WITH A TROF EXTENDING SW INTO THE ROCKIES WHERE ANOTHER SHORTWAVE WAS LOCATED OVER UT/CO. THIS SHORTWAVE WILL BEGIN TO AFFECT THE UPPER GREAT LAKES LATER TODAY AND TONIGHT AS IT LIFTS NE. BTWN THE SYSTEMS OVER HUDSON BAY AND THE ROCKIES...SHORTWAVE RIDGING IS SUPPORTING SFC HIGH PRES OVER THE WRN GREAT LAKES EARLY THIS MORNING. EXCELLENT RADIATIONAL COOLING CONDITIONS DURING THE NIGHT HAVE ALLOWED TEMPS TO FALL INTO THE MID 20S TO LWR 30S ACROSS MUCH OF THE INTERIOR OF UPPER MI. HERE AT NWS MQT...THE TEMP SO FAR AS OF 09Z HAS FALLEN TO 30F...MAKING THIS THE FIRST NIGHT THIS AUTUMN WITH A MIN TEMP AT OR BLO FREEZING. THIS TIES 1997 FOR THE LATEST OCCURRENCE OF THE FIRST MIN TEMP AT OR BLO FREEZING IN AUTUMN. SFC HIGH PRES OVER THE AREA WILL SLOWLY MOVE E TODAY WHILE SHORTWAVE OVER THE ROCKIES LIFTS NE INTO THE WRN PLAINS. FORCING ASSOCIATED WITH WAVE WILL REMAIN WELL W AND SW OF HERE TODAY. HOWEVER...RIGHT ENTRANCE OF STRENGTHENING UPPER JET ACROSS NRN ONTARIO/SRN MANITOBA WILL BRING INCREASING UPPER DIVERGENCE OVER THE UPPER MISSISSIPPI VALLEY. UPPER DIVERGENCE ASSOCIATED WITH THE JET IS ALREADY AIDING SOME BANDS OF -SHRA ACROSS ND INTO NW MN EARLY THIS MORNING PER RADAR IMAGERY THOUGH NOT ALL OF IT IS REACHING THE GROUND. THRU LATE AFTN...PLACEMENT OF THE UPPER JET OVER NRN ONTARIO/SRN MANITOBA WILL LEAD TO BEST UPPER DIVERGENCE REMAINING W OF THE FCST AREA AS DOES ISENTROPIC ASCENT AT THE LOWER LEVELS. IN ADDITION...DRY AIR MASS OVER THE AREA (SIMILAR TO 00Z KINL SOUNDING) WILL TAKE SOME TIME TO SATURATE...ESPECIALLY SINCE MAIN MOISTURE TRANSPORT REMAINS TO THE W OVER MN. THUS...PLAN TO MAINTAIN DRY WEATHER ACROSS UPPER MI TODAY...BUT WILL BRING CHC POPS INTO WRN LAKE SUPERIOR MID/LATE AFTN AS ERN FRINGE OF PCPN AREA MAY MAKE SOME PROGRESS INTO DRIER AIR. OTHERWISE...EXPECT A SLOW/STEADY INCREASE IN HIGH/MID CLOUDS THRU THE DAY FROM W TO E AS CLOUDS SPREAD DOWNWIND FROM THE UPPER DIVERGENCE/ISENTROPIC ASCENT AREA TO THE W. GUIDANCE IS WELL CLUSTERED ON MAX TEMPS TODAY...GENERALLY MID/UPPER 50S. AS UPPER JET TO THE N LIFTS SLIGHTLY N AND E...THERE SHOULD BE AN AREA OF -SHRA THAT SHIFTS ACROSS WRN AND NRN LAKE SUPERIOR TONIGHT...PROBABLY TO THE N OF UPPER MI. MEANWHILE...SHORTWAVE OVER THE WRN PLAINS WILL LIFT TO SE SD/SW MN/NW IA BY 12Z TUE WITH HEALTHY FORCING NOTED BY DEEP LAYER QVECTORS SPREADING TOWARD UPPER MI LATE. COMBINED WITH STRONG MOISTURE TRANSPORT AND STRONG ISENTROPIC ASCENT NOTED ON THE 300K SFC...EXPECT SHRA TO ADVANCE NE INTO WRN UPPER MI OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 426 AM EDT MON OCT 14 2013 MODELS ARE IN DECENT GENERAL AGREEMENT THROUGH THE EXTENDED...BUT LACK AGREEMENT ON SPECIFIC DETAILS /ESPECIALLY FOR TUE-WED/ THAT LEADS TO A MORE UNCERTAIN FORECAST. A NEARLY STACKED LOW PRESSURE SYSTEM WILL BE OVER FAR SW MN AT 12Z TUE...WITH WAA DRIVEN PRECIP OVER THE W AND CENTRAL CWA THROUGH TUE MORNING. AS THE SYSTEM MOVES OVER OR S OF THE CWA /DEPENDING OF MODEL SOLUTION/ THE TRACK OF THE LOW WILL BECOME MORE IMPORTANT AS A TROWAL WILL ACCOMPANY THE LOW. MODELS HAVE SLOWED THE SYSTEM DOWN A BIT FROM 24 HOURS AGO...AND THERE IS STILL DISAGREEMENT ON THE TIMING OF THE SYSTEM. THE 00Z/14 GFS AND 00Z/14 NAM ARE FASTER AND FARTHER N WITH THE TIMING/TRACK...WHICH MOVES THE TROWAL AND ASSOCIATED RAIN E FASTER ON WED. THE 12Z/13 GEM AND 12Z/13 ECMWF ARE SLOWER...BUT STILL DISAGREE ON THE EXACT TRACK. IF THE MORE SOUTHERN SOLUTION OF THE ECMWF VERIFIES...EVEN THOUGH IT IS SLOWER...RAIN WILL NOT LAST AS LONG ON WED AS EVEN THE GFS/NAM ARE SAYING SINCE THE TROWAL WOULD BE S/SE OF THE CWA WED AFTERNOON. THE SLOWER AND FARTHER N SOLUTION OF THE GEM WOULD RESULT IN THE LONGEST LASTING RAIN AS THE TROWAL STAYS OVER THE CWA INTO EARLY WED NIGHT. WILL CONTINUE TO LEAN TOWARD THE SLOWER SOLUTION GIVEN MODEL TRENDS IN THAT DIRECTION. WILL ALSO KEEP POPS HIGH TUE AND TUE NIGHT AS CONFIDENCE OFF AREA WIDE RAIN IS GOOD AT THAT TIME. FOR WED NIGHT INTO EARLY THU...MODELS GIVE A BRIEF REPRIEVE FROM TROUGHING AS A WEAK RIDGE MOVES OVERHEAD. AFTER THAT...A DEEP UPPER LOW WILL MOVE S FROM HUDSON BAY CLOSER TO THE INTERNATIONAL BORDER IN ONTARIO THROUGH SUN. THIS WILL BRING AN INCREASINGLY COLD AIRMASS OVERHEAD THROUGH AT LEAST THE WEEKEND. LOOKS LIKE A COLD FRONT WILL MOVE THROUGH ON THU...BUT PRECIP IS UNCERTAIN ALONG THE FRONT AS MODELS DISAGREE ON HOW MUCH SYNOPTIC FORCING WILL BE AVAILABLE FROM THE UPPER TROUGH MOVING INTO THE REGION. WILL NOT GO HIGHER THAN SLIGHT CHANCE POPS FOR THU. BY 00Z SAT...850MB TEMPS COOL TO AROUND -2C...SO EXPECT LAKE ENHANCED PRECIP ALONG A SECONDARY AND STRONGER COLD FRONT ON FRI GIVEN LAKE SFC TEMPS OF 9C TO 13C. MODELS THEN SHOW 850MB TEMPS DECREASING TO -5C TO -7C FRI NIGHT THROUGH SUN AS MULTIPLE ROUNDS OF UPPER LEVEL ENERGY MOVE THROUGH. WITH THESE COLDER TEMPS...EXPECT PURE LAKE EFFECT PRECIP WITH INCREASES IN INTENSITY WITH ENHANCEMENT FROM ANY CONTRIBUTING SYNOPTIC ENERGY. AS FOR PRECIP TYPE...SHOULD BE ABLE TO SEE ALL SNOW AT NIGHT/MORNING WHEN TEMPS ARE COOLEST FRI NIGHT THROUGH SUN MORNING...AND MAINLY OVER THE HIGHER TERRAIN. OTHERWISE...HIGH TEMPS WILL BE IN THE 40S SO SNOW IS NOT EXPECTED DURING THE WARMER DAYTIME HOURS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT) ISSUED AT 113 AM EDT MON OCT 14 2013 EXPECT VFR CONDITIONS THROUGH THE NEXT 24 HRS AS HIGH PRES REMAINS IN CONTROL. HIGH CLOUDS WILL BE MOVING INTO THE AREA LATER TODAY AHEAD OF DEVELOPING LOW PRESSURE IN THE PLAINS. RAIN AND LOWER CIGS/VSBYS EXPECTED BY TUESDAY MORNING. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 527 AM EDT MON OCT 14 2013 HIGH PRES OVER THE WRN LAKES WILL RESULT IN LIGHT WINDS ACROSS LAKE SUPERIOR...MOSTLY UNDER 15KT THRU MID AFTN. LATER TODAY AND TONIGHT...EASTERLY WINDS WILL BEGIN TO INCREASE FROM W TO E AS THE HIGH SHIFTS E AND LOW PRES LIFTS NE THRU THE PLAINS. BY TUE AFTN...E TO NE WINDS WILL BE INTO THE 20-30KT RANGE OVER WRN LAKE SUPERIOR. AS THE LOW MOVES ENE JUST TO THE S OF LAKE SUPERIOR TUE AFTN THRU WED MORNING...THESE STRONGER WINDS GENERALLY IN THE 20-30KT RANGE WILL SPREAD W TO E ACROSS THE REST OF LAKE SUPERIOR WHILE THE WINDS BACK NORTHERLY. IT`S NOT OUT OF THE QUESTION THAT THERE COULD BE A PERIOD OF GALES TUE NIGHT/WED MORNING ON THE BACKSIDE OF THE LOW. WINDS WILL THEN DIMINISH W TO E WED AFTN/NIGHT AS THE LOW MOVES FARTHER E AND A WEAK SFC HIGH PRES RIDGE ARRIVES. AT THIS TIME...IT APPEARS WINDS WILL MOSTLY BE AOB 20KT THU/FRI. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...TITUS AVIATION...MRD MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS HASTINGS NE
445 AM CDT MON OCT 14 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 445 AM CDT MON OCT 14 2013 AN ACTIVE 24 HOURS WITH QUITE HIGH MEASURABLE RAIN CHANCES IS ALREADY UNDERWAY ACROSS THE CWA...WITH PLENTY OF FORECAST CHALLENGES RANGING FROM TRYING TO REFINE SHORT-TERM POPS...ASSESSING THE MAGNITUDE OF A POSSIBLE SEVERE WEATHER RISK THIS AFTERNOON-EARLY EVENING...DETERMINING THE EFFECTS OF WIDESPREAD CLOUD COVER/PRECIP ON HIGH TEMPS...AND ALSO TRYING TO DETERMINE HOW CLOSE ESPECIALLY THE NORTHWESTERN CWA MAY COME TO AT LEAST BRIEFLY FLIRTING WITH WIND ADVISORY CRITERIA TONIGHT IN THE WAKE OF THE PASSING LOW. 08Z OBJECTIVE SURFACE ANALYSIS REVEALS A GRADUALLY-TIGHTENING PRESSURE GRADIENT...BETWEEN A ROUGHLY 1031 MILLIBAR HIGH OVER THE GREAT LAKES...AND A 1006 LOW OVER NORTHEAST CO. AS A RESULT...SUSTAINED SOUTHEAST WINDS ACROSS MOST OF THE CWA AT THIS HOUR ARE AVERAGING AT LEAST 10-15 MPH WITH HIGHER GUSTS TO AROUND 20 MPH...ESPECIALLY IN THE WEST. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A VIGOROUS MID/UPPER LEVEL TROUGH PLOWING ACROSS THE ROCKIES...WITH ITS 500MB VORT MAX CURRENTLY SWINGING OVER THE 4-CORNERS AREA. UPPER LEVEL FLOW HAS BECOME INCREASINGLY DIFFLUENT OVER THE CENTRAL PLAINS AHEAD OF A 100+KT JET STREAK APPROACHING FROM SOUTHERN CO...AND FARTHER DOWN A 40-50KT SOUTHERLY LOW LEVEL JET IS EVIDENT AT 850MB...RIGHT OVER THE HEART OF CENTRAL/WESTERN NEB AND KS. MUCH AS EXPECTED FOR DAYS NOW...STOUT LOW-MID LEVEL MOISTURE ADVECTION ESPECIALLY EVIDENT IN THE 850-700MB LAYER HAS RESULTED IN A GRADUAL INCREASE IN SHOWER/THUNDERSTORM ACTIVITY WITHIN THE CWA DURING THE NIGHT. OF COURSE...ITS NOT RAINING EVERYWHERE AT ONCE...AND EARLIER ON MOST OF THE PRECIP WAS FOCUSED IN NORTHWESTERN COUNTIES...BUT OVER THE PAST FEW HOURS THE MAIN FOCUS HAS TRANSITIONED TO ROUGHLY THE EASTERN 1/2 OF THE CWA...WITH MUCH OF THE WEST IN AT LEAST A SHORT TERM LULL. ALTHOUGH ITS QUITE POSSIBLE THAT A FEW OF THE STRONGER STORMS EARLY THIS MORNING HAVE PRODUCED/COULD PRODUCE VERY SMALL HAIL...NOT EXPECTING ANY SEVERE STORMS GIVEN MUCAPE IN THE 850-700MB LAYER ONLY AVERAGING A FEW HUNDRED J/KG PER LATEST RAP- BASED MESOANALYSIS. NOT SURPRISINGLY...TEMPS HAVE BEEN FAIRLY STEADY EARLY THIS MORNING UNDER WHAT HAS BECOME WIDESPREAD LOW CLOUD COVER AND SLOWLY-INCREASING DEWPOINTS...WITH MOST ALL PLACES CURRENTLY SOMEWHERE IN THE 50S. FOCUSING ON THE DAYTIME HOURS TODAY THROUGH 00Z/7PM...TOOK A BEST STAB AT 3-HOURLY POP TRENDS...BUT THE BOTTOM LINE IS THAT THE ENTIRE CWA IS SPORTING AN 80-90 PERCENT CHANCE OF MEASURABLE RAIN THROUGH SUNSET...ITS JUST A MATTER OF WHEN IT FALLS AND HOW MUCH FALLS. IN THE BIG PICTURE...THE PRIMARY 500MB VORT MAX ASSOCIATED WITH THE INCOMING TROUGH IS SCHEDULED TO REACH THE NEB PANHANDLE BY MID-DAY AS IT DEEPENS AND SWINGS NORTHEAST IN A NEGATIVELY TILTED FASHION...AND THEN REACHING FAR NORTH CENTRAL NEB BY AROUND SUNSET. IN SUIT...THE ASSOCIATED SURFACE LOW CURRENTLY CENTERED IN NORTHEAST CO IS PROGGED TO SHIFT NORTHEAST AS WELL...BUT SLIGHTLY SOUTHEAST OF THE MID LEVEL LOW TRACK...MEANING THAT IT GENERALLY SKIRTS JUST ALONG THE FAR WEST-CENTRAL/NORTHWEST EDGES OF THE CWA AS IT TRACKS NORTHEAST INTO NORTH CENTRAL NEB BY SUNSET WITH A CENTRAL PRESSURE AROUND 1003MB. MEANWHILE...A STOUT 50+KT LOW LEVEL JET WILL PERSIST OVER THE CWA PRETTY MUCH ALL DAY...WHICH IN TANDEM WITH CONTINUED LOW-MID LEVEL THETA-E ADVECTION SHOULD PROMOTE RATHER WIDESPREAD SHOWERS AND AT LEAST ISOLATED TO SCATTERED EMBEDDED THUNDERSTORMS THROUGH MUCH OF THE DAY. ITS YET TO BE SEEN WHETHER THIS WIDESPREAD PRECIPITATION MAINLY STAYS FOCUSED ACROSS THE EASTERN HALF OF THE CWA AS CURRENTLY HAPPENING...OR EVENTUALLY ALSO DEVELOPS OVER...OR MOVES INTO WESTERN AREAS AS WELL. MODELS VARY...WITH SOME ENDING THE LULL OVER THE WEST BY MID-MORNING...WHILE OTHERS SUCH AS THE LATEST HRRR CONTINUE TO FOCUS ON EASTERN AREAS AT LEAST THROUGH MID-DAY. AT ANY RATE...WOULD BE QUITE SURPRISED IF ANY OF THE CWA GOT THROUGH THE ENTIRE DAY WITHOUT MEASURABLE RAIN...AS MANY EASTERN AREAS COULD EASILY RECEIVE 0.50-0.75 INCH OR MORE THROUGH SUNSET. TURNING TO THE AFTERNOON HOURS...AS HAS ALSO BEEN ADVERTISED FOR A FEW DAYS NOW WE ARE FACING A CONDITIONAL SEVERE WEATHER THREAT...AS SPC HAS THE MAJORITY OF THE CWA IN A DAY 1 SLIGHT RISK AREA. THE MILLION DOLLAR QUESTION HERE IS...HOW MUCH CLEARING WILL TAKE PLACE JUST WEST OF...AND POSSIBLY INTO THE FAR SOUTHWESTERN PORTIONS OF THE CWA THIS AFTERNOON UNDER THE INVADING MID LEVEL DRY SLOT AND JUST AHEAD OF THE INVADING COLD FRONT/DRYLINE COMBO...TO PROMOTE SUFFICIENT DESTABILIZATION FOR SEVERE STORMS. FOLLOWING THE LEAD OF THE LATEST RAP...THE VAST MAJORITY OF THE CWA WILL REMAIN LOCKED UNDER LOW CLOUDS AND SCATTERED TO WIDESPREAD ELEVATED PRECIP THROUGH NEARLY THE ENTIRE DAY...WITH LIKELY NOTHING MORE THAN A HIT AND MISS THREAT OF SMALL HAIL POSSIBLY UP TO AROUND DIME SIZE. HOWEVER...BY MID-LATE AFTERNOON...THE RAP BRINGS A NARROW NORTH-SOUTH CORRIDOR OF LOW-LEVEL CAPE POTENTIALLY INTO THE 1000-1500 J/KG RANGE INTO MAINLY THE WESTERN 1/4 OF THE CWA. AS A RESULT...AND AS DEPICTED FAIRLY WELL BY THE 00Z RUNS OF THE 4KM WRF-NMM AND ARW AND ALSO THE LATEST HRRR...A LINE OF FAST MOVING STRONG TO POTENTIALLY SEVERE STORMS COULD SWEEP FROM WEST- EAST ACROSS MUCH OF THE CWA MAINLY BETWEEN 4PM-9PM...BUT LIKELY GRADUALLY LOSING STEAM AS IT DOES SO. ALTHOUGH LOW LEVEL SHEAR WILL BE STRONG...THUS MEANING THAT A BRIEF TORNADO THREAT IS NON- ZERO...EXPECT SYNOPTIC FORCING TO BE STRONG ENOUGH TO FORCE A LINEAR MODE FAIRLY QUICKLY...WITH THE MAIN THREAT BEING WINDS GUSTS TO AT LEAST 60 MPH...AND MAYBE SOME MARGINALLY SEVERE HAIL TO AROUND QUARTER SIZE. ALTHOUGH THE SPC SLIGHT RISK AREA COVERS NEARLY THE ENTIRE CWA...WILL BE FOCUSING THE LOCAL HAZARDOUS WEATHER OUTLOOK MAINLY ON THE SOUTHWEST HALF OF THE CWA...OR ROUGHLY SOUTHWEST OF A LOUP CITY-BELOIT LINE WHERE INSTABILITY SHOULD BE MAXIMIZED BEFORE IT DROPS OFF FARTHER EAST AS NIGHT FALLS. TURNING BRIEFLY TO OTHER ELEMENTS TODAY...HIGH TEMPERATURES WILL BE QUITE TRICKY AND OBVIOUSLY VERY DEPENDENT ON HOW MUCH PRECIP IS FALLING AND WHETHER ANY CLEARING TAKES PLACE IN THE SOUTHWEST...BUT BASED ON A VARIED BLEND OF SHORT TERM MODELS/GUIDANCE HAVE A RANGE FROM ONLY MID-UPPER 50S NORTH TO MID- UPPER 60S SOUTHWEST...WHICH IS A BIT COOLER THAN A STRAIGHT MET/MAV GUIDANCE BLEND AND COUNTS ON LOW CLOUDS HOLDING FIRM ACROSS MOST OF THE AREA. WIND-WISE TODAY...ALTHOUGH CERTAINLY QUITE BREEZY WITH SUSTAINED SOUTH-SOUTHEAST SPEEDS AVERAGING 20-25 MPH WITH GUSTS TO AROUND 30 MPH AHEAD OF THE APPROACHING COLD FRONT...NOT EXPECTING SUSTAINED SPEEDS TO BREACH ADVISORY CRITERIA OF 30+ MPH. TURNING TO THE TONIGHT PERIOD/7PM-7AM/...THE MAIN FOCUS IS ON HOW QUICKLY CONVECTION VACATES THE AREA...AND HOW STRONG WEST- NORTHWEST WINDS BECOME. ON THE BIG PICTURE...THERE IS GOOD AGREEMENT THAT THE CENTER OF THE CLOSED MID LEVEL LOW WILL ONLY SLOWLY MIGRATE FROM FAR NORTH CENTRAL NEB TO NEAR SIOUX FALLS...WHILE THE ATTENDANT SURFACE LOW FOLLOWS A SIMILAR PATH AND MAINTAINS A SIMILAR CENTRAL PRESSURE AROUND 1003MB. IN THE STOUT COLD AIR ADVECTION REGIME BEHIND THE DEPARTING LOW...AND IN AN ENHANCED PRESSURE GRADIENT BETWEEN THE SURFACE LOW AND AN EXPANSIVE HIGH NOSING INTO THE REGION FROM THE NORTHERN ROCKIES...ITS QUITE POSSIBLE THAT ESPECIALLY THE NORTHWEST HALF OF THE CWA MAY BE OVERALL-WINDIER TONIGHT THAN THEY ARE DURING THE DAY TODAY...EXCEPT THIS TIME OUT OF THE WEST-NORTHWEST BEHIND THE QUICKLY PASSING COLD FRONT...WHICH IS SLATED TO CRUISE ACROSS THE CWA GENERALLY BETWEEN 5-11PM. ALTHOUGH ITS NOT OUT OF THE QUESTION THAT THE LATEST SUITE OF MODELS/GUIDANCE ARE UNDER-DOING WIND SPEEDS A BIT...AT LEAST FOR NOW EXPECT SUSTAINED SPEEDS TO ONLY AVERAGE IN THE 20-25 MPH RANGE WITH GUSTS OF 30-35 MPH...AND THUS FALLING AT LEAST SLIGHTLY SHORT OF ADVISORY CRITERIA. NEIGHBORING OFFICES TO THE WEST HAVE ISSUED WIND HEADLINES FOR PORTIONS OF TODAY/TONIGHT...BUT AT THIS POINT JUST DON/T SEE THE LOCAL AREA BEING QUITE WINDY ENOUGH TO JUSTIFY AN ADVISORY...ALTHOUGH OF COURSE LATER SHIFTS WILL HAVE TO RE-EVALUATE THIS. OTHERWISE...IN TERMS OF PRECIP TRENDS...HAVE SLIGHTLY SPED UP THE DEPARTURE OF SHOWERS/STORMS...WITH MUCH OF THE WESTERN 1/2 OF THE CWA LIKELY DRIED OUT BY AROUND SUNSET...WHILE LIKELY POPS CONTINUE IN EASTERN COUNTIES THROUGH 02Z/9PM BEFORE QUICKLY DIMINISHING AND ENDING BY MIDNIGHT. ITS POSSIBLE THAT STORMS COULD CARRY AT LEAST A MARGINAL SEVERE THREAT UNTIL THEY DEPART EASTERN AREAS...BUT WOULD EXPECT THE MAIN THREAT TO DIMINISH POST-SUNSET. ALTHOUGH THE MAIN AREA OF PRECIP WILL VACATE THE AREA THIS EVENING...DID INTRODUCE A SLIGHT CHANCE OF LIGHT RAIN TO FAR NORTHERN ZONES THROUGH THE LATE EVENING/OVERNIGHT HOURS TO ACCOUNT FOR PRECIPITATION POSSIBLY BARELY BRUSHING THE CWA ON THE SOUTH-END OF THE WRAP-AROUND SHIELD. THE VAST MAJORITY OF THIS SHOULD FOCUS ACROSS FAR NORTHERN NEB HOWEVER. MADE LITTLE CHANGE TO OVERNIGHT LOWS...WITH MOST OF THE CWA BOTTOMING OUT IN THE 39-42 RANGE BY SUNRISE TUESDAY...ALTHOUGH ESPECIALLY THE NORTHWEST HALF OF THE AREA MAY BE HELD UP A BIT BY PLENTY OF LOW STRATUS WRAPPING BACK SOUTHWARD INTO THE AREA. THOSE VENTURING OUT LATE TONIGHT/EARLY TUESDAY WILL DEFINITELY NOTICE A BITE TO THE AIR...WITH WIND CHILL READINGS WELL DOWN INTO THE 30S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 445 AM CDT MON OCT 14 2013 PRIMARY CONCERNS WILL BE WINDY CONDITIONS ON TUESDAY AND LOW TEMPERATURES WITH FROST/FREEZE CHANCES ON WEDNESDAY AND THURSDAY MORNING. BUSY PATTERN STARTING OUT TUESDAY MORNING AS 500MB CLOSED LOW IS EXPECTED TO BE NEAR THE SDAK/MN BORDER WITH THE SYSTEM STACKED AS SURFACE LOW SHOULD BE JUST A TAD SOUTHEAST OF THE UPPER LOW POSITION. IN ADDITION TO THE UPPER LOW...TROUGHINESS IS EXPECTED TO EXTEND WESTWARD TOWARD THE CENTRAL ROCKIES. AS NOTED ABOVE...EXPECT WINDY CONDITIONS DURING THE DAYTIME TUESDAY AS WE SIT IN BETWEEN A WOUND UP SURFACE LOW NEAR THE MN/IA BORDER AND A STRONG HIGH PRESSURE BUILDING INTO CENTRAL WYOMING. THIS WILL RESULT IN A 20MB PRESSURE GRADIENT ACROSS NEBRASKA. SHOULD SEE SUSTAINED 25 MPH WINDS AT LEAST AND MAY BE APPROACHING ADVISORY CRITERIA ESPECIALLY IN THE NORTHERN HALF OF THE CWA FROM MID MORNING TO MID AFTERNOON. SOME LIGHT RAIN ALSO POSSIBLE ON TUESDAY IN THE NORTHERN QUARTER OF THE CWA WRAPPING AROUND THE LOW PRESSURE. IF WE DO GET ANY IT SHOULD NOT AMOUNT TO MUCH MORE THAN ONE OR TWO HUNDREDTHS. BY WEDNESDAY MORNING THE SURFACE LOW WILL HAVE MOVED INTO THE GREAT LAKES REGION WITH THE SURFACE HIGH BUILDING INTO OUR AREA. THIS WILL BRING LIGHTER WINDS AND ALSO EXPECTING SKIES TO CLEAR OUT...SO WITH DEWPOINTS IN THE UPPER 20S TO NEAR 30...MUCH OF THE CWA STANDS A DECENT CHANCE OF SEEING FROST WED MORNING. ON THURSDAY ANOTHER MID LEVEL WAVE WILL SLIDE ACROSS DRAGGING A COLD FRONT THROUGH THE CWA. DOESN`T APPEAR TO BE MUCH MOISTURE WITH THIS SYSTEM AND WILL KEEP FORECAST DRY. FRIDAY IS A LITTLE MORE INTERESTING AS A DEEP UPPER LOW SWINGS ACROSS CANADA AND THE NORTHERN PART OF THE U.S. THE EC MODELS BRINGS DOWN MUCH COLDER AIR THAN THE OPERATIONAL GFS. IT ALSO BRINGS A STRONG MID LEVEL WAVE DOWN THE BACKSIDE OF THE LOW ON FRIDAY AND GENERATES SOME MODERATE QPF WITH IT. THE GFS NOT SHOWING THIS AND THE GEM IS ALSO UNDERPLAYING THIS FEATURE. CHECKING THE ALL BLEND POPS...THEY ARE ONLY IN THE 15 TO 20 PERCENT RANGE FOR THE DAYTIME FRIDAY. BACK TO THE EC...IF ONE WERE TO ONLY LOOK AT 1000-500 MB THICKNESSES...THERE MAY BE CAUSE FOR CONCERN AS THE EC IS SHOWING THICKNESSES CONDUCIVE FOR SNOW. HOWEVER...A CLOSER EXAMINATION OF THE FORECAST SOUNDINGS FROM THE EC SHOWS SURFACE TEMPS IN THE UPPER 30S FRIDAY MORNING. ALSO THE GROUND SHOULD BE FAIRLY WARM SINCE HIGHS ON WED AND THURSDAY WILL BE NEAR 60. SO IF THE EC DOES VERIFY WITH THE MID LEVEL WAVE...WOULD EXPECT ANY PRECIP THAT OCCURS TO BE MORE OF A COLD RAIN. OF COURSE THIS WILL NEED TO BE MONITORED OVER THE NEXT FEW DAYS. && .AVIATION...(FOR THE 06Z KGRI TAF THROUGH 06Z MONDAY NIGHT) ISSUED AT 100 AM CDT MON OCT 14 2013 A FAIRLY ACTIVE 24 HOURS OF WEATHER AWAITS THE TERMINAL...WITH VARIOUS CONCERNS INCLUDING LOW LEVEL WIND SHEAR...SEVERAL HOURS OF PREVAILING MVFR CEILINGS WITH IFR NOT OUT OF THE QUESTION...GOOD CHANCES FOR SEVERAL ROUNDS OF PASSING SHOWERS/THUNDERSTORMS...AND FINALLY A PRONOUNCED WIND SHIFT BEHIND A COLD FRONT MONDAY EVENING. GOING ROUGHLY IN CHRONOLOGICAL ORDER WITH THESE ISSUES...HAVE MAINTAINED A MENTION OF LOW LEVEL WIND SHEAR THROUGH 15Z...AS A STRONG LOW LEVEL JET STREAM WILL MAINTAIN AT LEAST A 30-40KT WIND VECTOR DIFFERENCE BETWEEN THE SURFACE AND ROUGHLY 1800 FT AGL...THANKS TO WINDS AT THE TOP OF THIS LAYER AVERAGING AROUND 50KT FROM THE SOUTH. SECONDLY...STRONG MOISTURE ADVECTION WILL USHER IN HIGH-END MVFR CEILING WITHIN THE NEXT FEW HOURS...WITH THIS CEILING LIKELY LOWERING INTO LOW-END MVFR THRESHOLDS FOR MUCH OF THE DAYTIME HOURS. HAVE KEPT OUT ANY IFR CEILING FOR NOW...BUT SOME MODEL GUIDANCE SUGGESTS IT IS ALSO POSSIBLE. AS TIME GOES BY EARLY THIS MORNING INTO THE DAYTIME HOURS...SCATTERED TO NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS WILL BECOME INCREASINGLY LIKELY...AND AM ADVERTISING EITHER VCSH/VCTS OR OUTRIGHT PREVAILING -SHRA THROUGH THE FIRST 21 HOURS OF THE PERIOD...BEFORE THERE IS FAIRLY HIGH CONFIDENCE THAT ANY RISK OF PRECIP ENDS MONDAY EVENING. SURFACE WINDS WILL REMAIN FAIRLY CONSISTENT FROM THE SOUTHEAST AT SUSTAINED SPEEDS 15-20KT WITH GUST POTENTIAL TO AT LEAST 26KT THROUGH THE DAYTIME HOURS...BEFORE AN ABRUPT SWITCH TO WESTERLY WINDS OCCURS AROUND SUNSET AS THE COLD FRONT PASSES...WITH GUST POTENTIAL CONTINUING TO AT LEAST 26KT WELL INTO THE NIGHT. WILL ALSO RAISE CEILING BACK INTO LOW-END VFR TERRITORY BEHIND THIS FRONT...BUT PLENTY OF PASSING LOW-LEVEL STRATUS COULD STICK AROUND THROUGH THE NIGHT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...EWALD AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
355 AM CDT MON OCT 14 2013 .DISCUSSION... MAIN FORECAST CHALLENGE IS TIMING THE RAIN TODAY THROUGH TUESDAY...AND DETERMINING RAINFALL AMOUNTS. AT 08Z...SHOWERS WITH A FEW THUNDERSTORMS WERE MOVING THROUGH PARTS OF NEBRASKA...THEN EXTENDED SOUTHWEST THROUGH COLORADO AND INTO NORTHERN NEW MEXICO. THIS AREA OF PRECIPITATION WAS IN RESPONSE TO A DEEP UPPER LOW SPINNING OVER UTAH PER WATER VAPOR IMAGERY. ASSOCIATED WITH THE LOW WAS AN IMPRESSIVE JET MAX OF AROUND 145 KNOTS AS INDICATED BY THE RAP MODEL ANALYSIS NEAR THE COLORADO- NEW MEXICO BORDER. NUMEROUS LIGHTNING STRIKES WERE NOTED WITHIN THIS PRECIPITATION AREA. THE SURFACE CYCLOGENESIS RESPONSE TO THE UPPER LOW WAS MAXIMIZED FROM SOUTHEAST WYOMING INTO SOUTHWEST SOUTH DAKOTA WHERE 3 HOURLY PRESSURE FALLS WERE 2-3MB. BASED ON THE 100 METER 500MB HEIGHT RISES ON THE BACK SIDE OF THE UPPER TROUGH...THE EXPECTED SCENARIO IS FOR THE UPPER LOW TO MOVE FROM UTAH INTO THE NEBRASKA PANHANDLE BY THIS AFTERNOON. THAT WILL PIVOT THE JET AXIS TO A MORE EAST-WEST ORIENTATION...POSITIONING IT ACROSS SOUTHEAST COLORADO-SOUTHERN KANSAS. EXPECT STRONG UPWARD FORCING DUE TO A COMBINATION OF: THE UPPER DIVERGENCE FROM THE LEFT FRONT EXIT REGION OF THE JET MAX...STRONG DPVA AHEAD OF THE UPPER LOW...ISENTROPIC LIFT IN THE WARM CONVEYER BELT REGION...AND CONTINUED SURFACE CYCLOGENESIS. ALL OF THIS POINTS TO A WELL-DEFINED EXTRATROPICAL CYCLONE PATTERN MOVING THROUGH THE PLAINS TODAY AND THIS EVENING...WITH A SURFACE COLD FRONT MOVING THROUGH EASTERN NEBRASKA AND SOUTHWEST IOWA TONIGHT. IN THESE SCENARIOS WE CAN PLAN ON SOMEWHAT HEAVY RAINS AHEAD OF THE LOW DURING THE DAY TODAY AND INTO THE EVENING...THEN THE DRY SLOT PUSHING INTO THE REGION OVERNIGHT TONIGHT. THEN AS THE UPPER LOW MOVES NORTHEAST OF THE REGION...SCATTERED SHOWERS SHOULD OCCUR ON THE BACK SIDE OF THE LOW IN THE DEFORMATION ZONE. RAINFALL AMOUNTS OF 2 INCHES WILL BE POSSIBLE NEAR THE SOUTH DAKOTA BORDER...WITH CLOSER TO 0.5 INCH NEAR THE MISSOURI BORDER...AND 1-1.5 INCHES NEAR I-80. THESE AMOUNTS ARE SUPPORTED BY FAIRLY GOOD MODEL AGREEMENT WITH THE OVERALL PATTERN AS WELL AS THE MODEL RAINFALL. THIS ACTIVE PATTERN SHOULD BE ACCOMPANIED BY A STRONG SOUTHERLY LOW LEVEL JET OF AROUND 60 KNOTS THIS AFTERNOON AND EVENING...THEN 40-45 KNOTS OUT OF THE NORTHWEST TUESDAY. THUNDERSTORMS THAT DEVELOP ON THE EASTERN EDGE OF THE DRY SLOT OVER SOUTH CENTRAL NEBRASKA THIS AFTERNOON/EVENING MAY BE QUITE STRONG AND COULD MOVE NORTHEAST INTO AREAS GENERALLY WEST AND SOUTH OF NORFOLK. BEHIND THE COLD FRONT...TEMPERATURES WILL BE ABOUT 10 DEGREES COLDER TUESDAY THAN TODAY WITH GUSTY NORTHWEST WINDS...CLOUDS...AND SCATTERED LIGHT SHOWERS ESPECIALLY IN NORTHEAST NEBRASKA. SURFACE HIGH PRESSURE MOVES IN WEDNESDAY WITH COOL/QUIET WEATHER. THE PATTERN OVER NORTH AMERICA SETTLES INTO A HIGH AMPLITUDE RIDGE ALONG THE WEST COAST WITH A BROAD LONGWAVE TROUGH FROM HUDSON BAY INTO THE SOUTHERN US...AND THIS KEEPS THE CENTRAL PLAINS IN A COOL NORTHWEST FLOW REGIME INTO NEXT WEEK. NIETFELD && .AVIATION... 06Z TAFS FOR KOFK...KOMA AND KLNK. CEILINGS WILL DECREASE AND PCPN WILL BE INCREASING IN COVERAGE OVERNIGHT...IN RESPONSE TO LOW PRESSURE SYSTEM APPROACHING FROM THE WEST. KOFK COULD SEE MVFR CONDITIONS PRIOR TO 12Z...WITH MVFR CONDITIONS MOVING IN BETWEEN 12Z AND 18Z AT KLNK AND KOMA. AT LEAST TEMPORARY IFR CONDITIONS POSSIBLE AFTER 18Z AT KOFK AND KLNK WITH TSRA. STRONG LOW LEVEL WINDS JUST ABOVE GROUND LEVEL WILL RESULT IN LOW LEVEL WIND SHEAR LATER TONIGHT INTO MONDAY MORNING. EXPECT IMPROVING CONDITIONS AFTER 06Z TUESDAY FOR KLNK AND KOMA BUT LOW CLOUDS SHOULD REMAIN IN THE KOFK AREA. MILLER && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
430 AM EDT MON OCT 14 2013 .SYNOPSIS... STALLED SURFACE FRONT NEAR OHIO RIVER TODAY. FRONT WASHES OUT TUESDAY. A STRONGER COLD FRONT MOVES THROUGH WEDNESDAY. POST FRONTAL DISTURBANCE RACES THROUGH LATE THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... WASHED OUT/STALLED SURFACE FRONT...REALLY MORE A WEAK PRESSURE TROUGH AT THIS POINT...RUNS FROM JUST WEST OF CKB TO JUST EAST OF HTS. DO HAVE SOME SOME MORE ENHANCED ECHOS SHOWING UP ALONG OR JUST WEST OF THIS BOUNDARY...AND ALSO IN NORTH CENTRAL WV. UPPED TO SCATTERED SHOWERS IN THESE AREA THROUGH THE EARLY MORNING. RAP SHOWS AN ELONGATED VORT LOBE MOVING ACROSS CWA THIS MORNING...SO KEEP SOME ISOLATED TO SCATTERED SHOWERS IN THE OHIO RIVER VALLEY TRANSITIONING MORE TO THE NORTHERN MOUNTAINS THIS AFTERNOON. LOW LEVEL MOISTURE STILL STRUGGLES TO CLEAR OUT...SO THINK PLENTY OF CLOUDS AROUND TODAY...EXCEPT VERY WESTERN CWA WHERE SATELLITE SHOWS CLEAR SKIES ALREADY DRIFTING IN. VORT LOBE AND ASSOCIATED POPS SHOULD BE MOVING OUT OF NORTHERN MOUNTAINS LATE AFTERNOON INTO EVENING...WITH A PRECIP FREE FORECAST BY LATE TONIGHT. COOLED HIGHS JUST A BIT TODAY WITH ABUNDANCE OF CLOUDS AND STAYED NEAR TO JUST ABOVE THE WARMER MET FOR LOWS TONIGHT. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AFTER A VERY STRANGE PATTERN OF LATE...WE FINALLY GET THE ATMOSPHERE MOVING AGAIN DURING THIS TUESDAY THROUGH THURSDAY NIGHT TIME PERIOD. SO SEVERAL FEATURES TO TIME. DRIER AIR AT 925 TO 850 MBS THAT IS OFF THE JERSEY COAST THIS PREDAWN SHOULD CONTINUE TO SNEAK BACK WSW AND REACH OUR MOUNTAINOUS COUNTIES FOR TUESDAY. SO EXPECTING LESS CLOUDS THERE DURING TUESDAY AFTERNOON...COMPARED TO SAY OUR OHIO COUNTIES. WARMEST DAY OF THE WEEK SHOULD BE TUESDAY. WITH THE 700 MB FLOW INCREASING IN THE LOWER OHIO VALLEY TUESDAY NIGHT. WAS JUST A BIT FASTER BRINGING BACK SOME CHANCE POPS FOR PREFRONTAL SHOWERS OVERNIGHT TUESDAY NIGHT IN THE WEST. ALSO...KEPT TEMPERATURES MILDER THAN MOST MOS GUIDANCE THERE. INITIAL TIMING OF FRONT IS THROUGH OUR OHIO RIVER VALLEY COUNTIES BY MIDDAY AND ACROSS THE MOUNTAINOUS COUNTIES BY SUNSET. SO...THE ONLY CHANGE WORTH MENTIONING WAS A BIT FASTER LOWERING POPS FROM WEST TO EAST. LEFT OUR FRONTAL POPS IN THE LIKELY RANGE...WAS NOT IMPRESSED ENOUGH TO RAISE TO CATEGORICAL. WITH THAT TIMING...LOWERED DAYTIME MAXIMUM TEMPERATURES A FEW DEGREES WEDNESDAY. WITH 850 TEMPERATURES DROPPING SOME 6 TO 8C OVERNIGHT WEDNESDAY NIGHT...HELD ONTO SOME POPS OVER THE MOUNTAIN COUNTIES...AS WE SQUEEZE OUT THE LOW LEVEL MOISTURE. YET...FURTHER WEST...AT LEAST PARTIAL CLEARING AS EVEN THE 850 MOISTURE THINS OUT. FOR THURSDAY AND THURSDAY NIGHT...THE MORE RECENT RUNS OF THE ECMWF HAVE COME AROUND TO WHAT THE GFS HAD BEEN ADVERTISING PREVIOUSLY. THE MID LEVEL DISTURBANCE RACES THROUGH HERE THURSDAY EVENING. MOISTURE INCREASES FOR THURSDAY AFTERNOON AND EVENING. SO HELD THURSDAY MORNING DRIER THAN OUR PREVIOUS FORECAST...BUT STILL INCREASED POPS THURSDAY AFTERNOON. THINK CLEARING WILL DEVELOP IN OUR WESTERN LOWLANDS THURSDAY NIGHT. WILL LOWER TEMPERATURES FOR DAWN FRIDAY...ESPECIALLY FOR SOUTHEAST OHIO...NORTHEAST KENTUCKY...AND SPILLING INTO A FEW RURAL AREAS OF WESTERN WEST VIRGINIA. HAVE SOME 35 TO 40 DEG TEMPERATURES THERE...WILL MENTION/ADD THE POSSIBILITY OF FROST IN A FEW SPOTS IN THE HAZARDOUS WEATHER POTENTIAL...BUT CURRENTLY DO NOT THINK IT WILL BE WIDESPREAD. && .LONG TERM /FRIDAY THROUGH SUNDAY/... MODELS ARE HAVING DISAGREEMENTS ON HANDLING A SOUTHERN STREAM SYSTEM ON THURSDAY IN THE SPLIT FLOW UPPER AIR PATTERN. ALL AGREE THAT A NORTHERN STREAM SHORT WAVE AND ASSOCIATED COLD FRONT WILL QUICKLY EXIT EARLY WEDNESDAY NIGHT...TAKING THE SHOWERS WITH IT. SOME COOLER AND DRIER AIR DOES FLOW IN BEHIND THIS FRONT WEDNESDAY NIGHT. THE BIG QUESTION BECOMES WHAT HAPPENS TO A CHUNK OF ENERGY LEFT OVER THE SOUTHERN ROCKIES AS IT GETS QUICKLY EJECTED BY ANOTHER NORTHERN STREAM SHORT WAVE DROPPING OUT OF WESTERN CANADA. WILL GO WITH PERSISTENCE IN OUR FORECAST AND ENOUGH MODEL CONSENSUS...USING LATEST GFS AND ECMWF MODELS AVAILABLE...WITH THIS SHORT WAVE LIFTING UP FAR ENOUGH WEST TO DRIVE SURFACE LOW PRESSURE NORTHEASTWARD FROM THE LOWER MISSISSIPPI VALLEY THRU THE MID ATLANTIC THURSDAY. THIS WILL BRING A SWATH OF RAIN ACROSS THE AREA THURSDAY...ESPECIALLY IN THE EAST. OTHERWISE...OUTSIDE A WEAK AND RATHER MOISTURE LIMITED COOL FRONT SATURDAY...HIGH PRESSURE WILL GENERALLY DOMINATE FRIDAY THRU THE WEEKEND. EXPECT TEMPERATURES TO BE A LITTLE BELOW NORMAL FOR THIS TIME OF YEAR...BUT NO SIGNIFICANT FREEZE/FROST OUTSIDE THE HIGHER ELEVATIONS OF THE WEST VIRGINIA IS EXPECTED THRU THE WEEKEND. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... CURRENT OBS SHOW IFR CIGS ACROSS THE LOWLANDS...WITH VFR ACROSS THE MOUNTAINS...HOWEVER EXPECT EASTERN CWA TO GRADUALLY DROP BACK INTO MVFR AND IFR AT BKW THROUGH THE REMAINDER OF THE EARLY MORNING. COULD SEE SOME POCKETS OF FOG...BUT EXPECT IT TO REMAIN MOSTLY OF THE MVFR VARIETY WITH DENSE CLOUD COVER. CLEAR SKIES ON SATELLITE JUST INTO WESTERN CWA...AND COULD SEE THIS PUSH TOWARDS HTS...AND POSSIBLY PKB OVER THE NEXT 6 HOURS...BUT SIDED WITH MODEL SOUNDINGS IN KEEPING CLOUDS IN PLACE. SHOULD IT CLEAR...DENSE FOG WOULD BE POSSIBLE. SLOWED DOWN RETURN TO VFR TODAY...HOWEVER ALL SITES SHOULD REBOUND AS THE DAY GOES ALONG WITH SOME ISOLATED TO SCATTERED SHOWERS DRIFTING AROUND AS A VORT LOBE PASSES. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY... FORECAST CONFIDENCE: LOW TO MEDIUM. ALTERNATIVE SCENARIOS: HTS MAY CLEAR AND FOG. TIMING OF CIG CAT CHANGES ACROSS CWA MAY VARY...WITH SOME BOUNCING AROUND POSSIBLE. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE MON 10/14/13 UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19 EDT 1HRLY 04 05 06 07 08 09 10 11 12 13 14 15 CRW CONSISTENCY L L H H H H H H H H H H HTS CONSISTENCY L M M M M M H H H H H H BKW CONSISTENCY L L L H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY L H H H H H H H H H H H CKB CONSISTENCY H H H H H H H H H H H H AFTER 06Z TUESDAY... IFR POSSIBLE IN CONVECTION WEDNESDAY WITH A COLD FRONT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...MZ SHORT TERM...KTB LONG TERM...JMV AVIATION...MZ
AREA FORECAST DISCUSSION
NWS BROWNSVILLE TX
1231 AM CDT MON OCT 14 2013 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...DEBRI CLOUDS FROM THUNDERSTORM ACTIVITY ACROSS SOUTH CENTRAL TEXAS WILL SPREAD SOUTHWARD INTO THE RIO GRANDE VALLEY TONIGHT. THUNDERSTORMS ARE EXPECTED TO IMPACT ZAPATA AND JIM HOGG COUNTY UNTIL SUNRISE PRODUCING MODERATE TO HEAVY RAIN GUSTY WINDS AND FREQUENT CLOUD TO GROUND LIGHTNING. EXPECT MVFR CONDITIONS DEVELOPING DURING THE EARLY MORNING HOURS OVER KBRO... KHRL AND KMFE IMPROVING AFTER SUNRISE. BREEZIER SE WINDS WILL DEVELOP MONDAY WITH ISOLATED SHOWERS POSSIBLE IN THE AFTERNOON HOURS. && .PREV DISCUSSION... /ISSUED 929 PM CDT SUN OCT 13 2013/ DISCUSSION...MONITORING CONVECTION THAT HAS SO FAR REMAINED TO THE NORTHWEST OF THE CWA. HOWEVER TRENDS OVER THE LAST COUPLE OF HOURS IN WATER VAPOR IMAGERY SUGGEST THAT A RIPPLE IN THE SUBTROPICAL JET...WHICH IS BEING ENHANCED BY OUTFLOW OF TS OCTAVE WILL LEAD TO STRONGER DIFFLUENCE PUSHING SOUTHEAST AND HOLDING THROUGH SUNRISE. LOW LAYER ANALYSIS AND THE NAM12/RAP SUGGEST INCREASING CONVERGENCE OVER MAINLY JIM HOGG/ZAPATA COUNTY OVER THE NEXT COUPLE OF HOURS. THERE IS FAIRLY WEAK BUT NONZERO INSTABILITY AND DEEP MOISTURE WITH SATELLITE AND RAP PWAT ESTIMATES AROUND 2.2 INCHES WHICH IS REASONABLY IN LINE WITH 00Z REGIONAL BALLOON RELEASES. WITH AT LEAST SOME BAROCLINICITY IN THE 850/700MB LAYER MORE FOCUSED REGIONAL TROUGHING COULD SET UP ALONG OUR NORTHWESTERN ZONES THROUGH THE NIGHT AS WELL. CONSIDERING THE ABOVE HAVE RAISED PRECIP CHANCES THROUGH THE OVERNIGHT MAINLY IN ZAPATA/BROOKS/STARR/JIM HOGG COUNTIES. LOCAL FLOODING RISK STILL APPEARS LIMITED BY A STABILIZING BOUNDARY LAYER BUT WILL CONTINUE TO MONITOR. -JGG/GB PREV DISCUSSION... /ISSUED 622 PM CDT SUN OCT 13 2013/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. AVIATION...GUSTY SOUTHEAST WINDS WILL FALL TO AROUND 7 TO 10 KNOTS OVER THE NEXT FEW HOURS. CONVECTION IS EXPECTED TO REMAIN NORTHWEST OF THE TAF SITES BUT ISOLATED ACTIVITY IS POSSIBLE ACROSS JIM HOGG AND ZAPATA COUNTY THROUGH THE EARLY EVENING. DRIER AIR AROUND 3000 FT IS EXPECTED TO HELP KEEP CIGS VFR BUT PATCHY HIGH MVFR IS POSSIBLE...ESPECIALLY AROUND SUNRISE AND HAVE INCLUDED A TEMPO GROUP DURING THAT TIME PERIOD. CLOUD DECKS SHOULD RISE ABOVE 3000 FT AND BECOME SCATTERED TO FEW BY MID MORNING AS SOUTHEASTERLY WINDS INCREASE AND PERSIST THROUGH THE DAY ON MONDAY. /68-JGG/ PREV DISCUSSION... /ISSUED 319 PM CDT SUN OCT 13 2013/ SHORT TERM /NOW THROUGH MONDAY NIGHT/...H5 RIDGE CONTINUES TO SPIN JUST OT THE SOUTH...WITH MOISTURE CONTINUING TO WRAP AROUND IT. WEAK IMPULSE EXPECTED TODAY WENT FURTHER NORTH THAN FORECAST...SO SHOWERS HAVE BEEN ISOLATED AND HAVE FOR THE MOST PART MOVED OFF TO THE NORTH. MOISTURE IS FORECAST TO GET SHUNTED FURTHER NORTHWARD DURING THE NEXT 12 HOURS...WHILE MUCH DRIER AIR NOTED TO THE SOUTH ON WV IMAGERY WILL REPLACE IT STARTING TONIGHT. THIS SHOULD PUT AN END TO THE POP CHANCES FOR THE SHORT TERM PERIOD. TEMPERATURES WILL AGAIN RISE INTO THE LOW 90S TOMORROW WITH ANOTHER HUMID DAY IN STORE. LONG TERM /TUESDAY THROUGH SUNDAY/...THE 500 MB RIDGING IN PLACE OVER THE GULF OF MEX AND SOUTHERN TX WILL BE STEADILY ERODED AWAY LATER THIS WEEK AS A SERIES OF STRONG SHORT WAVES WILL DIG ACROSS THE WESTERN AND CENTRAL STATES. THIS WILL PUSH A COLD FRONT THROUGH DEEP SOUTH TX LATE WED NIGHT/EARLY THURS MORNING WITH A SECOND FRONT PUSHING ACROSS CENTRAL AND SOUTHERN TX THIS SATURDAY. AS THE MID LEVEL RIDGING ERODES AWAY THE DEEPER LAYER MOISTURE FEED (WHICH IS BEING ENHANCED FROM THE LEFT OVER MOISTURE FROM T.S. OCTAVE IN THE EASTERN PAC) WILL SHIFT STEADILY SOUTHWARDS AHEAD OF THE NEXT FRONT INCREASING THE CONV POTENTIAL DURING THE LATER HALF OF THE WEEK. THE OLD COLD FRONT WILL REMAIN STATIONARY TO THE SOUTH OF THE REGION ON SUN WITH BROAD HIGH PRESSURE SPREADING OVER MUCH OF THE CENTRAL AND EASTERN STATES. BOTH THE ECMWF AND GFS GENERALLY AGREE IN THE HANDLING OF THE SYNOPTIC FEATURES AND THE OVERALL MOISTURE TRENDS THROUGH THURS. AT THIS POINT THE GFS DEVIATES FROM THE ECMWF AND TRIES TO DEVELOP A SURFACE COASTAL LOW NEAR THE LOWER TX COASTLINE AND LIFTS THIS FEATURE SLOWLY NORTHEAST NEXT WEEKEND. THE ECMWF DOES NOT REFLECT THIS FEATURE AS WELL AND TENDS TO WANT TO DRY OUT THE AREA MUCH FASTER AS SURFACE RIDGING STRENGTHENS OVER THE REGION. FOR NOW WILL GO CLOSE TO THE GFS SOLUTION THROUGH THURS AND WILL LEAN TOWARDS THE ECMWF SOLUTION FOR THE WEEKEND. OVERALL CONFIDENCE FOR THE LONGER RANGE PERIOD IS ABOVE AVERAGE THROUGH AROUND THURS AND IS THEN ONLY AVERAGE AFTER THURS DUE TO THE MODEL DIFFERENCES. WILL GO FAIRLY CLOSE TO GFS MEX MOS TEMPS THROUGH THE WEEKEND AND WILL LEAN TOWARDS THE DRIER ECMWF POPS AFTER THURSDAY. MARINE...NOW THROUGH MONDAY NIGHT...MINIMAL CHANGE IN MARINE FORECAST THROUGH THE NEXT 36 HOURS. WEAK RIDGING CONTINUES ACROSS THE NORTHERN GULF...WHILE THE NEXT COLD FRONT ENTERS NORTH TEXAS. WINDS WILL REMAIN IN THE 10 TO 15 KNOT RANGE THROUGH MONDAY NIGHT...WHILE SEAS STAY GENERALLY BETWEEN 3 AND 4 FEET. TUESDAY THROUGH FRIDAY...A LIGHT TO MODERATE SE FLOW WILL PREVAIL TUES AND WED AHEAD OF THE NEXT FRONT. A MODERATE TO STRONG N-NE FLOW WILL DOMINATE IN BEHIND THE FRONT ON THURS. HOWEVER ONLY BORDERLINE SCA CONDITIONS MAY OCCUR AS THE STRONG PGF MAY BE FAIRLY SHORT LIVED. A MODERATE ONSHORE FLOW WILL PREVAIL INTO FRI AS SURFACE RIDGING SAGS OVER THE GULF OF MEX. THIS WILL MAINTAIN MODERATES SWELLS AS THE WEEKEND APPROACHES. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV 67/61
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1128 PM CDT SUN OCT 13 2013 UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE .SHORT TERM...TONIGHT AND MONDAY ISSUED AT 227 PM CDT SUN OCT 13 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A LARGE HIGH PRESSURE SYSTEM GRADUALLY MOVING EAST OVER THE NORTHERN PLAINS TO MID-MISSISSIPPI VALLEY. LINGERING WEAK CYCLONIC FLOW AND THERMAL TROUGHING HAVE KEPT A STUBBORN STRATO-CU FIELD OVER THE NE THIRD OF THE STATE...THOUGH ITS GRADUALLY BREAKING UP. LOOKING UPSTREAM...MID AND HIGH CLOUDS ARE ADVANCING NE OVER THE PLAINS AHEAD OF THE NEXT STORM SYSTEM. SO WITH HIGH PRESSURE MOVING IN...FORECAST CONCERNS ARE CLOUDS...TEMPS AND FROST HEADLINES. TONIGHT...SURFACE HIGH PRESSURE WILL BE SETTLING ACROSS THE WESTERN GREAT LAKES REGION...PROVIDING MOSTLY CLEAR SKIES AND LIGHT WINDS. SHOULD SEE HIGH CIRRUS MOVE INTO NORTHERN WISCONSIN THIS EVENING...WHILE LIGHT EASTERLY FLOW WILL DEVELOP OVER THE LAKE MICHIGAN SHORELINE LATE. SOME CONCERN ABOUT LAKE CLOUDS MOVING INLAND THAT COULD MESS AROUND WITH FROST FORMATION OVER EAST-CENTRAL WISCONSIN. HOWEVER...THE EASTERLY FLOW WILL GENERALLY BE 5 KTS OR UNDER...AND LOCAL DATA SUGGESTS LAND BREEZES WILL DEVELOP THAT WILL KEEP LAKE INDUCED CLOUDS OFFSHORE. AS A RESULT...WILL LOWER TEMPS OVER EAST-CENTRAL WISCONSIN...WHERE LOCATIONS AWAY FROM LAKE MICHIGAN WILL LIKELY FALL INTO THE MIDDLE 30S. THESE CONDITIONS WILL LEAD TO THE POTENTIAL OF FROST SO WITH COLLAB FROM OTHER OFFICES...WILL HOIST A FROST ADVISORY EXCEPT FOR DOOR COUNTY. MONDAY...HIGH PRESSURE WILL REMAIN OVER THE AREA. IN ADDITION TO HIGH CLOUDS INCREASING FROM WEST TO EAST OVER THE AREA...EASTERLY WINDS STRENGTHEN SOME DURING THE MORNING...AND POSSIBLY ENOUGH TO PUSH A MID-LAKE CLOUD BAND INLAND. WILL INCREASE CLOUD COVER OVER EAST-CENTRAL WISCONSIN DURING THE MORNING. THINK THESE CLOUDS WILL GRADUALLY DISSIPATE DURING THE AFTERNOON...SO WILL CONTINUE TO SHOW MORE SUN EAST VERSUS WEST. HIGH TEMPS MAINLY IN THE MID TO UPPER 50S. .LONG TERM...MONDAY NIGHT THROUGH SUNDAY ISSUED AT 227 PM CDT SUN OCT 13 2013 PATTERN OVER CONUS FOR THE NEXT WEEK TO CONSIST OF STRONG UPPER RIDGE ALONG THE WEST COAST WITH A BROAD UPR TROF ACROSS THE CENTRAL U.S. UNSETTLED WEATHER EXPECTED INTO WEDNESDAY AS UPPER TROF/ASSOCIATED SFC LOW AND COLD FRONT MOVE THRU THE GREAT LAKES. PCPN CHANCES CONTINUE...ALBEIT LOWER POPS THROUGH THE REMAINDER OF THE PERIOD AS COOLER AIR ALOFT SETTLES OVER THE REGION AND A SECONDARY WEAK COLD FRONT/TROF MOVE THRU. TEMPS TO BE NEAR NORMAL THRU THU AND THEN FALL BELOW NORMAL BY THE END OF THE WEEK. PCPN CHANCES INCREASE THROUGH THE NIGHT MON AS WAA PATTERN SPREADS EAST OVER THE REGION. MODELS CONTINUE TO SHOW DRY LAYER IN MID LEVELS THROUGH MUCH OF THE NIGHT MON. HAVE SLOWED PCPN A BIT EARLY EVENING...THOUGH LEFT REST OF PREVIOUS FORECAST STAND...STAYING DRY OVER THE EAST. WIDESPREAD PCPN EXPECTED TUE INTO TUE EVENING AS SURFACE LOW MOVES THROUGH STATE. DEEPER MOISTURE STRIPPED OUT LATER TUE NIGHT/WED LEADING TO LOWER POPS OR LIGHT PCPN. STILL HAVE TIMING DIFFERENCE THROUGH MUCH OF THE EXTENDED...THUS HAVE LEANED TOWARDS GFS ENSEMBLE FORECAST. HAVE BUMPED WINDS UP ON LAKE/BAY THROUGH THE EXTENDED GIVEN COLD AIR MASS MOVING IN. && .AVIATION...FOR 06Z TAF ISSUANCE ISSUED AT 1127 PM CDT SUN OCT 13 2013 CLEAR SKIES AND MAYBE SOME PATCHY GROUND FOG EXPECTED IN MOST PLACES TONIGHT. SOME LAKE EFFECT CLOUDS MAY FORM NEAR LAKE MICHIGAN AND THE BAY TOWARDS MORNING. BEST GUESS IS THAT CLOUDS BASES WILL BE BETWEEN 2500 FT AND 3500FT. LAKE EFFECT CLOUDS MAY LINGER AT MTW/SUE/GRB/MNM/OCQ WITH JUST INCREASING HIGH CLOUDS ELSEWHERE. && .GRB WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY FROM 3 AM TO 8 AM CDT MONDAY FOR WIZ038-039- 048>050. && $$ SHORT TERM.....MPC LONG TERM......TE AVIATION.......RDM
AREA FORECAST DISCUSSION
NWS RIVERTON WY
1120 PM MDT SUN OCT 13 2013 .UPDATE... INSERTED 06Z AVIATION DISCUSSION BELOW. && .PREV DISCUSSION... /ISSUED 422 PM MDT SUN OCT 13 2013/ SHORT TERM...TONIGHT THROUGH MONDAY MAIN TROUGH AXIS IS LOOMING TO OUR WEST OVER IDAHO...NEVADA AND UTAH. THIS TROUGH WILL BE RESPONSIBLE FOR ACCUMULATING SNOW...MAINLY IN OUR MOUNTAINS...AS WELL AS THE LOWER ELEVATIONS OF JOHNSON COUNTY TONIGHT THROUGH MONDAY EVENING. CURRENTLY WE ARE UNDER THE SOUTHWEST UPPER DIFLUENT UPPER FLOW ASSOCIATED WITH THE LEFT FRONT QUAD OF THE JET WHICH IS RESPONSIBLE FOR LIGHTNING ALONG THE FAR WESTERN BORDER OF WYOMING FROM WEAK CONVECTIVE CELLS. THIS MORE CONVECTIVE ACTIVITY HAS REPLACED THE MORE STRATIFORM PRECIP ASSOCIATED WITH THE WEAK ISENTROPIC LIFT IN THE WEST. A CIRCULATION IS EVIDENT ON PIH RADAR IN EASTERN IDAHO JUST WEST OF THE CONVECTION WITH THE RUC INDICATING INCREASING INSTABILITY. HOWEVER...THE GFS...NAM AND THE ECMWF ALL AGREE ON KEEPING THE MAIN JET ENERGY WELL TO THE SOUTH TRACKING ACROSS THE 4 CORNERS AREA LATE TONIGHT WITH THE VORT ENERGY STRENGTHENING IN THE NORTHERN AND CENTRAL PLAINS MONDAY. THE SURFACE FLOW IS OUT OF THE NORTHEAST ATTM...EAST OF THE DIVIDE...BUT AT MAINLY LIGHT SPEEDS. ONCE THE MAIN LOW OVER NEBRASKA/SOUTH DAKOTA STARTS TO BOMB...THE NORTH WINDS EAST OF THE DIVIDE WILL STRENGTHEN AND THUS INCREASE UPSLOPE SNOWFALL POTENTIAL. THE GFS INDICATES 3 SEPARATE SUBTLE CIRCULATIONS AT 700MB THAT WILL TRACK EAST ACROSS VARIOUS PORTIONS OF WYOMING TONIGHT...NOT THE MOST ORGANIZED SYSTEM WITH ASSOCIATED Q VECTOR FORCING AND WEAK ISENTROPIC LIFT. WITH THE 700MB CIRCULATIONS TRACKING ACROSS OUR CWA...BUT WITH THE MAIN ENERGY WELL TO OUR SOUTH...THE THINKING WAS ADVISORY AMOUNTS OF SNOWFALL FOR MOST OF THE MOUNTAIN ZONES EAST OF THE DIVIDE...NAMELY THE WIND RIVER...ABSAROKA AND BIG HORN MOUNTAINS AS WELL AS CASPER MOUNTAIN. THE BIG HORNS AND CASPER MTN WILL LIKELY LAG BEHIND ROUGHLY SIX HOURS COMPARED TO THE WINDS AND THE ABSAROKAS. DECIDED TO ISSUE A WINTER STORM WARNING FOR THE BIG HORN MOUNTAINS TO ACKNOWLEDGE THE 30 TO 40 MPH WIND GUSTS...THE HIGH END SNOW ADVISORY AMOUNTS AND ALSO TAKING INTO ACCOUNT THE TIME OF YEAR AND ALL THE HUNTERS THAT WILL BE NEGOTIATING THE WINTER CONDITIONS. THE BULK OF THE COLDEST 700MB AIR WILL COME CLOSEST TO JOHNSON COUNTY WHERE ADVISORY SNOW AMOUNTS ARE INDICATED FOR THAT ZONE FOR MONDAY AND MONDAY EVENING. THE MOS GUIDANCE INDICATES ACCUMULATING SNOWFALL FOR BYG AND SHR BUT NONE FOR THE OTHER MOS GUIDANCE FORECAST POINTS WHERE 700MB TEMPS ARE PROGGED BY THE NAM TO BE -9.5C IN NORTHERN JOHNSON COUNTY 00Z TUESDAY. NOT ONLY IS ACCUMULATING SNOW EXPECTED FOR THE LOWER ELEVATIONS OF JOHNSON COUNTY BUT STRONG NORTH WINDS OF 30 TO 40 MPH WITH SOME GUSTS OF 50 MPH ARE EXPECTED THERE AS WELL ON MONDAY ONCE THE STORM BOMBS TO THE EAST. THE NIGHT SHIFT WILL NEED TO DECIDE WHETHER OR NOT THE LOWER ELEVATIONS OF JOHNSON COUNTY AND THE GREEN MTNS...FOR THAT MATTER...NEED A HILITE FOR MONDAY AND MONDAY EVENING. LONG TERM...MONDAY NIGHT THROUGH SUNDAY AFTER SOME LINGERING FLURRIES...MAINLY EAST OF THE DIVIDE...SURFACE HIGH PRESSURE WILL BEGIN TO BUILD OVER WYOMING LATE MONDAY NIGHT AND TUESDAY. THE WEST AND NORTH SHOULD CLEAR OUT FIRST...RESULTING IN A VERY CHILLY TUESDAY MORNING. LOW LEVEL CLOUDS COULD REMAIN OVER JOHNSON AND NATRONA COUNTIES EARLY TUESDAY MORNING BEFORE A CLEARING SKY. MOST OF THE FORECAST AREA WILL STILL SEE A SUNNY SKY BY TUESDAY AFTERNOON. NORTHWEST FLOW THEN SETS UP ALOFT OVER WYOMING. IT WILL BE DRY AND COLD TUESDAY NIGHT THROUGH WEDNESDAY NIGHT PER MODELS. FURTHER IN THE EXTENDED WILL HAVE TO WATCH FOR A FEW QUICK HITTING SHORTWAVES IN THIS NORTHWEST FLOW...BEGINNING EARLY THURSDAY. AS IT LOOKS NOW... WEST CENTRAL WYOMING WILL BE UNDER INFLUENCE OF THE DRIER NORTHERLY STREAM INTO NEXT WEEKEND. THE ECMWF IS MORE ROBUST WITH THESE EMBEDDED SHORTWAVES...BUT PREFER THE DRIER GFS FOR NOW. IF ANY AREA WERE TO SEE SOME SNOW SHOWERS IN THIS PATTERN...IT WOULD BE THE BIGHORN MOUNTAINS. THEREFORE...SLIGHTLY HIGHER POPS FOR BIGHORN MOUNTAINS THURSDAY AND FRIDAY. OTHERWISE...TEMPERATURES SHOULD BE NEAR OR SLIGHTLY BELOW NORMAL THROUGH THE PERIOD. AVIATION.../06Z ISSUANCE/ WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES UNSETTLED WEATHER WILL CONTINUE MONDAY WITH PERIODS OF MVFR/IFR CONDITIONS IN LOW CLOUDS AND SNOW SHOWERS. HOWEVER...MOST TERMINALS SHOULD SEE CEILINGS LIFT AT TIMES IN THE 035-050 KFT AGL RANGE. THE WORST CONDITIONS WILL PROBABLY OCCUR AT THE ROCK SPRINGS AND BIG PINEY TERMINALS. MOUNTAINS WILL BE OBSCURED WITH IFR CONDITIONS THROUGH MUCH IF NOT ALL OF THE FORECAST PERIOD. AVIATION CONDITIONS WILL GENERALLY BE WORSE EAST OF THE DIVIDE. EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES RAIN WILL CONTINUE TO CHANGE TO SNOW IN THE LOWER ELEVATIONS...AS A COLD FRONT SWEEPS SOUTHWARD...ALSO CHANGING SHOWERY PRECIP TO MORE STRATIFORM. MOST AREAS SHOULD CHANGE BY 14Z. WIDESPREAD IFR/MVFR CONDITIONS WILL OCCUR MONDAY IN SNOW AND LOW CLOUDS WITH WINDY NORTHERLY WINDS. THE WORST CONDITIONS WILL BE THROUGH 18Z TODAY. HOWEVER A CONTINUATION OF MVFR CONDITIONS IS LIKELY THROUGH TONIGHT...ESPECIALLY IN FAVORED UPSLOPE AREAS SUCH AS NEAR THE LANDER AND CASPER AREAS. MOUNTAINS WILL BE OBSCURED WITH LIFR CONDITIONS ACROSS MOUNTAIN PASSES. PLEASE SEE THE AVIATION WEATHER CENTER FOR THE LATEST INFORMATION ON ICING FORECASTS. FIRE WEATHER... IRE WEATHER WILL NOT BE A FACTOR IN THE NEXT DAY OR TWO DUE TO LOW PRESSURE OVER THE CENTRAL AND NORTHERN ROCKIES. THE LOW PRESSURE...AT THE SURFACE AND ALOFT...WILL RESULT IN AREAS OF SNOW. WINTER STORM WARNINGS AND ADVISORIES HAVE BEEN ISSUED FOR SOME OF THE WEST CENTRAL WYOMING MOUNTAIN RANGES. THIS SNOW WILL TAPER OFF BY MONDAY NIGHT. TUESDAY THROUGH WEDNESDAY WILL HAVE COOL TEMPERATURES AND VERY LITTLE WIND OR MIXING ACROSS THE REGION. && .RIW WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO MIDNIGHT MDT MONDAY NIGHT WYZ022. WINTER WEATHER ADVISORY UNTIL 6 PM MDT MONDAY WYZ002-015. WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO MIDNIGHT MDT MONDAY NIGHT WYZ008-009. WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO MIDNIGHT MDT MONDAY NIGHT WYZ010. WINTER WEATHER ADVISORY UNTIL 3 PM MDT MONDAY WYZ003. && $$ UPDATE...WM SHORT TERM...LIPSON LONG TERM...KPL AVIATION...WM FIRE WEATHER...KPL
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
759 AM MDT MON OCT 14 2013 .UPDATE...CONVECTION INCLUDING THUNDERSTORMS BREAKING OUT ALONG THE FRONT RANGE. HAVE UPDATED FORECAST FOR HIGHER POPS THIS MORNING AND THUNDERSTORMS. && .AVIATION...FOG IS IN THE PROCESS OF BEING REPLACED BY A BAND OF CONVECTIVE SHOWERS AND ISOLATED THUNDERSTORMS. MOST OF THESE WILL BE MOVING THROUGH 14Z-16Z WITH PARTIAL CLEARING AND SOME IMPROVEMENT IN CEILINGS WITH FRONT. COULD SEE GUSTS TO AROUND 35 KTS WITH THOSE SHOWERS AND STORMS. STILL A CHANCE OF SHOWERS AFTER 16Z BUT LESS WIND WITH THOSE. && .PREV DISCUSSION... /ISSUED 409 AM MDT MON OCT 14 2013/ SHORT TERM...TODAY AND TONIGHT...AN UPPER LEVEL TROUGH CENTERED NEAR THE FOUR CORNERS WILL LIFT NORTHEAST THIS MORNING AND CLOSE OFF OVER THE NEBRASKA PAN HANDLE AROUND 18Z. STRONG LIFT AHEAD OF THE TROUGH WILL CONTINUE TO BRING RAIN AND MOUNTAIN SNOW TO NORTHWEST AND NORTH CENTRAL COLORADO. SOUTHWEST FLOW AHEAD OF THE TROUGH IS BRINGING DRY AIR TO NORTHEAST COLORADO THIS MORNING...THE DRY SLOT. A SURFACE LOW OVER NORTHEAST COLORADO WILL MOVE INTO NEBRASKA THIS MORNING. AS IT LIFTS NORTHEAST IT WILL PULL A COLD FRONT ACROSS COLORADO. EXPECT THE FRONT TO PUSH ACROSS NORTHEAST COLORADO DURING THE LATE MORNING HOURS AS INDICATED BY THE GFS AND ECMWF. THE NAM...RAP AND HRRR ARE ALL MUCH LATER SHOWING THE FRONT PUSHING THROUGH DURING THE MID AFTERNOON. NORMALLY THE QUICKER SOLUTION OF THE GFS/ECMWF PANS OUT. APPEARS THE GFS IS HANDLING THE SURFACE PATTERN BETTER AND EXPECT ITS FORECAST TO BE BETTER. FOR THE FRONT RANGE...WILL HAVE TO WAIT UNTIL THE FRONT PASSES THROUGH AND UPSLOPE DEVELOPS FOR SHOWERS TO FORM. MOST OF THE SHOWERS WILL BE LIGHT AND DO NOT EXPECT MUCH FOR PRECIPITATION AMOUNTS. BETTER OROGRAPHIC LIFT WILL PREVAIL THIS AFTERNOON OVER THE MOUNTAINS DUE TO NORTHWEST FLOW AND COLD AIR ADVECTION. WILL KEEP THE ADVISORY GOING THROUGH 00Z. BASED ON CURRENT RADAR AND SATELLITE...APPEARS THE NORTH CENTRAL MOUNTAINS WILL SEE 2 TO 5 INCHES OF SNOW THROUGH SUNRISE. OROGRAPHIC LIFT TODAY SHOULD PRODUCE ANOTHER 2 TO 4 INCHES OF SNOW. ANOTHER THING TO WATCH WITH THIS SYSTEM WILL BE STRONG WINDS ON THE EASTERN PLAINS. STRONG COLD AIR ADVECTION BEHIND BEHIND THE FRONT WILL HELP STRONGER WINDS ALOFT MIX DOWN. THIS COMBINED WITH A TIGHT PRESSURE GRADIENT WILL PRODUCE WIND GUSTS OF 45 TO 55 MPH...JUST BELOW HIGH WIND CRITERIA. SOME WEAK SHOWERS WILL REMAIN POSSIBLE TONIGHT...MAINLY BEFORE MIDNIGHT. MAY GET COLD ENOUGH FOR A FEW SNOW SHOWERS ALONG THE FRONT RANGE AFTER SUNSET...BUT NO ACCUMULATION IS EXPECTED. EVEN THOUGH PRECIPITATION IS EXPECTED TO END...CLOUDY SKIES SHOULD LINGER THROUGH THE NIGHT. IT WILL BE A CHILLY NIGHT WITH MOST LOCATIONS FALLING BELOW FREEZING. LONG TERM...A CHILLY AND UNSETTLED AIRMASS IS STILL INDICATED OVER NORTHERN COLORADO AND WYOMING ON TUESDAY BENEATH A WESTERN EXTENSION OF THE MAIN UPPER TROUGH CENTERED EITHER OVER EASTERN SOUTH DAKOTA OR WESTERN MINNESOTA TUESDAY MORNING. MODELS ALSO INDICATE A 1030MB SFC HIGH IN THE COLDEST AIR COVERING NORTHERN WYOMING AND NORTH- NORTHWESTERLY SFC-700 MB FLOW OVER NORTH CENTRAL/NORTHEAST COLORADO. MODELS SHOW A SECONDARY UPPER LOW FORMING OVER EASTERN UTAH AROUND MIDDAY...AND THEN TRACKING SOUTHEASTWARD OVER SOUTHWESTERN COLORADO TUESDAY NIGHT. HEIGHT FALLS TO OUR SOUTHWEST IN COMBINATION WITH PRESSURE RISES IN ADVANCE OF THE SOUTHWARD TREKING SFC HIGH IS FORECAST TO PRODUCE WEAK TO MODERATE UPSLOPE FLOW OVER NORTHEAST COLORADO TUESDAY AFTERNOON/EVENING. AS A RESULT COULD SEE SCATTERED SNOW SHOWERS ON THE FRONT RANGE MTNS AND FOOTHILLS...AND ISOLATED RAIN AND SNOW SHOWERS ON THE ADJACENT PLAINS. ANY SNOW ACCUMULATION SHOULD BE MINIMAL. OVERNIGHT THIS SECONDARY UPPER LOW AND SFC HIGH MIGRATE SOUTH AND THE UPSLOPE FLOW ENDS...RESULTING IN AN END TO PRECIP AROUND HERE. MAX TEMPERATURES ON TUESDAY LIKELY TO BE THE COOLEST DURING THE UPCOMING WEEK. HIGHS AT LOWER ELEVATIONS NOT EXPECTED TO CLIMB OUT OF THE 40S. FOR REST OF THE WEEK...FLOW ALOFT RETURNS TO A NORTHWESTERLY COMPONENT WITH RIDGING OVER THE LOWER GREAT BASIN AND DESERT SOUTHWEST. THIS RESULTS IN WARMER TEMPERATURES AND DRY CONDITIONS ON WEDNESDAY. BY THURSDAY...THE ECMWF SHOWS A COLD FRONT RACING SOUTH OUT OF WYOMING AHEAD OF A CLIPPER SYSTEM DROPPING OUT OF THE NORTHERN ROCKIES. THE EC SHOWS THIS FRONT MOVING THROUGH NERN COLORADO THURSDAY MORNING. WHILE THE GFS DOESN/T SHOW IT ARRIVING UNTIL MUCH LATER IN THE DAY. THIS ADDS MORE UNCERTAINTY TO THE HIGH TEMPERATURE FCST FOR THAT DAY. THURSDAY NIGHT AND FRIDAY...ECMWF DRIVES THIS SYSTEM STRAIGHT SOUTH ALONG THE LEE SIDE OF THE ROCKIES INTO NORTHEAST COLORADO POTENTIALLY RESULTING IN AMPLE CLOUD COVER...SIGNIFICANTLY COOLER TEMPERATURES AND A GOOD CHANCE OF PRECIP...LIKELY IN THE FORM OF SNOW FOR THE MTNS AND PLAINS. THE CANADIAN GEM INDICATES A NEARLY SIMILAR PATTERN DEVELOPING...BUT NOT AS COLD OR AS WET. WHEREAS THE GFS SHOWS THIS SYSTEM JUST GLANCING THE AREA BRINGING ONLY SLIGHTLY COOLER TEMPERATURES AND ONLY A SLIGHT CHANCE OF PRECIP MAINLY TO THE NORTHEAST PLAINS. SINCE THIS IS STILL A FEW DAYS AWAY...WILL APPLY A BLEND OF THESE MODELS TO THIS FORECAST ISSUANCE. AVIATION...SOUTHERLY WINDS WILL TURN WEST THEN TO NORTHWEST THIS MORNING AHEAD OF AN APPROACHING COLD FRONT. THE FRONT IS EXPECTED TO PUSH THROUGH AROUND 16Z CAUSING WINDS TO TURN NORTHERLY. CLOUDS WILL INCREASE BEHIND THE FRONT AND SCATTERED RAIN SHOWERS WILL BE POSSIBLE. CEILINGS ARE EXPECTED TO BE 4000 TO 8000 FEET THIS AFTERNOON. CLOUDS WILL LOWER TONIGHT WITH CEILING OF 2000 TO 5000 FEET POSSIBLE. THERE WILL BE A CHANCE CEILINGS COULD FALL BELOW 2000 FEET BY 12Z TUESDAY. HYDROLOGY...NO CONCERNS. SCATTERED RAIN AND MOUNTAIN SNOW SHOWERS WILL MOVE ACROSS THE AREA THROUGH THIS EVENING. RAINFALL AMOUNTS WILL BE LESS THAN A QUARTER INCH. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ031- 033. && $$ SHORT TERM...BARJENBRUCH LONG TERM....BAKER AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
409 AM MDT MON OCT 14 2013 .SHORT TERM...TODAY AND TONIGHT...AN UPPER LEVEL TROUGH CENTERED NEAR THE FOUR CORNERS WILL LIFT NORTHEAST THIS MORNING AND CLOSE OFF OVER THE NEBRASKA PAN HANDLE AROUND 18Z. STRONG LIFT AHEAD OF THE TROUGH WILL CONTINUE TO BRING RAIN AND MOUNTAIN SNOW TO NORTHWEST AND NORTH CENTRAL COLORADO. SOUTHWEST FLOW AHEAD OF THE TROUGH IS BRINGING DRY AIR TO NORTHEAST COLORADO THIS MORNING...THE DRY SLOT. A SURFACE LOW OVER NORTHEAST COLORADO WILL MOVE INTO NEBRASKA THIS MORNING. AS IT LIFTS NORTHEAST IT WILL PULL A COLD FRONT ACROSS COLORADO. EXPECT THE FRONT TO PUSH ACROSS NORTHEAST COLORADO DURING THE LATE MORNING HOURS AS INDICATED BY THE GFS AND ECMWF. THE NAM...RAP AND HRRR ARE ALL MUCH LATER SHOWING THE FRONT PUSHING THROUGH DURING THE MID AFTERNOON. NORMALLY THE QUICKER SOLUTION OF THE GFS/ECMWF PANS OUT. APPEARS THE GFS IS HANDLING THE SURFACE PATTERN BETTER AND EXPECT ITS FORECAST TO BE BETTER. FOR THE FRONT RANGE...WILL HAVE TO WAIT UNTIL THE FRONT PASSES THROUGH AND UPSLOPE DEVELOPS FOR SHOWERS TO FORM. MOST OF THE SHOWERS WILL BE LIGHT AND DO NOT EXPECT MUCH FOR PRECIPITATION AMOUNTS. BETTER OROGRAPHIC LIFT WILL PREVAIL THIS AFTERNOON OVER THE MOUNTAINS DUE TO NORTHWEST FLOW AND COLD AIR ADVECTION. WILL KEEP THE ADVISORY GOING THROUGH 00Z. BASED ON CURRENT RADAR AND SATELLITE...APPEARS THE NORTH CENTRAL MOUNTAINS WILL SEE 2 TO 5 INCHES OF SNOW THROUGH SUNRISE. OROGRAPHIC LIFT TODAY SHOULD PRODUCE ANOTHER 2 TO 4 INCHES OF SNOW. ANOTHER THING TO WATCH WITH THIS SYSTEM WILL BE STRONG WINDS ON THE EASTERN PLAINS. STRONG COLD AIR ADVECTION BEHIND BEHIND THE FRONT WILL HELP STRONGER WINDS ALOFT MIX DOWN. THIS COMBINED WITH A TIGHT PRESSURE GRADIENT WILL PRODUCE WIND GUSTS OF 45 TO 55 MPH...JUST BELOW HIGH WIND CRITERIA. SOME WEAK SHOWERS WILL REMAIN POSSIBLE TONIGHT...MAINLY BEFORE MIDNIGHT. MAY GET COLD ENOUGH FOR A FEW SNOW SHOWERS ALONG THE FRONT RANGE AFTER SUNSET...BUT NO ACCUMULATION IS EXPECTED. EVEN THOUGH PRECIPITATION IS EXPECTED TO END...CLOUDY SKIES SHOULD LINGER THROUGH THE NIGHT. IT WILL BE A CHILLY NIGHT WITH MOST LOCATIONS FALLING BELOW FREEZING. .LONG TERM...A CHILLY AND UNSETTLED AIRMASS IS STILL INDICATED OVER NORTHERN COLORADO AND WYOMING ON TUESDAY BENEATH A WESTERN EXTENSION OF THE MAIN UPPER TROUGH CENTERED EITHER OVER EASTERN SOUTH DAKOTA OR WESTERN MINNESOTA TUESDAY MORNING. MODELS ALSO INDICATE A 1030MB SFC HIGH IN THE COLDEST AIR COVERING NORTHERN WYOMING AND NORTH- NORTHWESTERLY SFC-700 MB FLOW OVER NORTH CENTRAL/NORTHEAST COLORADO. MODELS SHOW A SECONDARY UPPER LOW FORMING OVER EASTERN UTAH AROUND MIDDAY...AND THEN TRACKING SOUTHEASTWARD OVER SOUTHWESTERN COLORADO TUESDAY NIGHT. HEIGHT FALLS TO OUR SOUTHWEST IN COMBINATION WITH PRESSURE RISES IN ADVANCE OF THE SOUTHWARD TREKING SFC HIGH IS FORECAST TO PRODUCE WEAK TO MODERATE UPSLOPE FLOW OVER NORTHEAST COLORADO TUESDAY AFTERNOON/EVENING. AS A RESULT COULD SEE SCATTERED SNOW SHOWERS ON THE FRONT RANGE MTNS AND FOOTHILLS...AND ISOLATED RAIN AND SNOW SHOWERS ON THE ADJACENT PLAINS. ANY SNOW ACCUMULATION SHOULD BE MINIMAL. OVERNIGHT THIS SECONDARY UPPER LOW AND SFC HIGH MIGRATE SOUTH AND THE UPSLOPE FLOW ENDS...RESULTING IN AN END TO PRECIP AROUND HERE. MAX TEMPERATURES ON TUESDAY LIKELY TO BE THE COOLEST DURING THE UPCOMING WEEK. HIGHS AT LOWER ELEVATIONS NOT EXPECTED TO CLIMB OUT OF THE 40S. FOR REST OF THE WEEK...FLOW ALOFT RETURNS TO A NORTHWESTERLY COMPONENT WITH RIDGING OVER THE LOWER GREAT BASIN AND DESERT SOUTHWEST. THIS RESULTS IN WARMER TEMPERATURES AND DRY CONDITIONS ON WEDNESDAY. BY THURSDAY...THE ECMWF SHOWS A COLD FRONT RACING SOUTH OUT OF WYOMING AHEAD OF A CLIPPER SYSTEM DROPPING OUT OF THE NORTHERN ROCKIES. THE EC SHOWS THIS FRONT MOVING THROUGH NERN COLORADO THURSDAY MORNING. WHILE THE GFS DOESN/T SHOW IT ARRIVING UNTIL MUCH LATER IN THE DAY. THIS ADDS MORE UNCERTAINTY TO THE HIGH TEMPERATURE FCST FOR THAT DAY. THURSDAY NIGHT AND FRIDAY...ECMWF DRIVES THIS SYSTEM STRAIGHT SOUTH ALONG THE LEE SIDE OF THE ROCKIES INTO NORTHEAST COLORADO POTENTIALLY RESULTING IN AMPLE CLOUD COVER...SIGNIFICANTLY COOLER TEMPERATURES AND A GOOD CHANCE OF PRECIP...LIKELY IN THE FORM OF SNOW FOR THE MTNS AND PLAINS. THE CANADIAN GEM INDICATES A NEARLY SIMILAR PATTERN DEVELOPING...BUT NOT AS COLD OR AS WET. WHEREAS THE GFS SHOWS THIS SYSTEM JUST GLANCING THE AREA BRINGING ONLY SLIGHTLY COOLER TEMPERATURES AND ONLY A SLIGHT CHANCE OF PRECIP MAINLY TO THE NORTHEAST PLAINS. SINCE THIS IS STILL A FEW DAYS AWAY...WILL APPLY A BLEND OF THESE MODELS TO THIS FORECAST ISSUANCE. && .AVIATION...SOUTHERLY WINDS WILL TURN WEST THEN TO NORTHWEST THIS MORNING AHEAD OF AN APPROACHING COLD FRONT. THE FRONT IS EXPECTED TO PUSH THROUGH AROUND 16Z CAUSING WINDS TO TURN NORTHERLY. CLOUDS WILL INCREASE BEHIND THE FRONT AND SCATTERED RAIN SHOWERS WILL BE POSSIBLE. CEILINGS ARE EXPECTED TO BE 4000 TO 8000 FEET THIS AFTERNOON. CLOUDS WILL LOWER TONIGHT WITH CEILING OF 2000 TO 5000 FEET POSSIBLE. THERE WILL BE A CHANCE CEILINGS COULD FALL BELOW 2000 FEET BY 12Z TUESDAY. && .HYDROLOGY...NO CONCERNS. SCATTERED RAIN AND MOUNTAIN SNOW SHOWERS WILL MOVE ACROSS THE AREA THROUGH THIS EVENING. RAINFALL AMOUNTS WILL BE LESS THAN A QUARTER INCH. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ031- 033. && $$ SHORT TERM...MEIER LONG TERM....BAKER AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
913 AM EDT MON OCT 14 2013 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE THROUGH TUESDAY...THEN WEAKEN TUESDAY NIGHT INTO WEDNESDAY...DRIFTING INTO THE CANADIAN MARITIMES. WEAK LOW PRESSURE WILL DEVELOP OFF THE EAST COAST WHILE A FRONTAL SYSTEM APPROACHES FROM THE GREAT LAKES. THE COLD FRONT WILL MOVE ACROSS THE AREA LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. WAVES OF LOW PRESSURE ARE THEN FORECAST TO IMPACT THE AREA FRIDAY AND SATURDAY NIGHT. ANOTHER COLD FRONT MOVES THROUGH LATE SATURDAY NIGHT INTO SUNDAY MORNING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FORECAST ON TRACK. HIGH PRESSURE REMAINS STRONG...ESPECIALLY NORTH AND EAST OF THE LOCAL REGION. ALOFT...A RIDGE WILL REMAIN DOMINANT WITH ITS BASE TO OUR SOUTH. A COLD FRONT ASSOCIATED WITH AN EQUIVALENT BAROTROPIC LOW IN EASTERN CANADA WILL WEAKEN THROUGH THE DAY WITH EASTWARD MOVEMENT. THE LOSS OF TEMPERATURE ADVECTIONS WILL CONTRIBUTE TO THE WEAKENING OF THIS SYSTEM AND INHERENTLY RESULTING IN THE FRONTOLYSIS. THE ONLY EFFECT OF THE FRONT WILL BE AN INCREASE IN THE MOISTURE IN THE 700 TO 850 MB COLUMN LATE THIS AFTERNOON. THE LOWEST INVERSION AROUND 900MB GOING INTO THIS MORNING IS SHOWN TO MIX OUT BUT THE ONE AROUND 700 TO 800MB WILL REMAIN ALLOWING FOR MOISTURE TO COLLECT HERE. THIS IS WHERE CLOUDS WILL DEVELOP. THERE IS UNCERTAINTY ON EXACTLY HOW MUCH CLOUDS THERE WILL BE AND THE TIMING OF THE HIGHER CLOUD COVERAGE AND THIS IS ONE PARAMETER THAT COULD FLUCTUATE WITH SUBSEQUENT FORECASTS. THE NAM AND RUC BUFKITS INDICATE THIS POSSIBILITY BUT DIFFER ON THE TIMING WHILE THE GFS BUFKITS DOES NOT MOISTEN THE 700 TO 850MB LAYER BUT IS SLOWER TO MIX OUT THE LOWEST INVERSION AROUND 900MB WITH ITS CLOUDS THIS MORNING. THE RESULTING UNCERTAINTY WAS THE REASON WHY AN EQUAL BLEND OF MAV AND MET GUIDANCE WAS CHOSEN FOR HIGH TEMPERATURES TODAY...WHICH ARE FORECAST TO BE IN THE MID TO UPPER 60S FOR A MAJORITY OF THE REGION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... HIGH PRESSURE WILL REMAIN DOMINANT TONIGHT WITH A WEAK COLD FRONT APPROACHING FROM THE WEST AND DISSIPATING. ONLY EXPECTING AN INCREASE IN CLOUDS FROM THIS WITHIN THE 700-850MB LAYER FROM WEST TO EAST. THERE IS A LITTLE HIGHER CONFIDENCE ON MORE CLOUDS TONIGHT. HENCE...LOWS WERE PREFERRED WITH A 3/4 MET WARMER GUIDANCE TO 1/4 COOLER MAV GUIDANCE. WILL KEEP FORECAST ON THE SLOWER SIDE WITH PROGRESSION OF CLOUDS CONSIDERING THE LOWERING BOUNDARY LAYER FLOW AND LACK OF WINDS TO MIX DOWN. THIS WILL RESULT IN MORE CLOUDS FOR TONIGHT. GOING WITH A WARMER DAY TUESDAY AS THE RIDGE SHIFTS EAST AND THERE IS MORE OF A SOUTHWEST FLOW ALOFT. THERE IS SOME PRETTY GOOD LOW LEVEL WARM ADVECTION TOO WITH THE SOUTHEAST FLOW AT 850MB VEERING TO THE SOUTHWEST FLOW AT 700MB. THE WINDS ARE SLIGHTLY MORE THAN THE PREVIOUS DAY. HIGH TEMPS WERE A BLEND OF THE WARMER MET 2/3 AND COOLER 1/3 MAV CONSIDERING THE WARM AIR ADVECTION. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... UPPER LEVEL RIDGE AXIS WILL SLIDE E OF THE AREA BY WED EVE WITH A TROUGH TRACKING TOWARDS THE AREA FROM THE GREAT LAKES/OHIO VALLEY REGION. THERE ARE TIMING DIFFERENCES WITH THE PROGRESSION OF THIS FIRST TROUGH WHICH HAS A RIPPLE EFFECT ON LATER PERIODS. THE GFS/GEFS MEAN IS FASTEST...FOLLOWED CLOSELY BY THE EC AND SREF...THEN THE NAM AND CMC AND LASTLY THE UKMET. HAVE STUCK WITH A MIDDLE OF THE ROAD SOLN...NAM/SREF BLEND UNTIL THIS IS BETTER RESOLVED. MEANWHILE...A BROAD UPPER LEVEL TROUGH WILL BE CARVED OUT THROUGH CENTRAL NOAM. A PROGRESSIVE PATTERN WILL DEVELOP ACROSS THE EASTERN US IN RESPONSE TO A TIGHT SW FLOW ALOFT. ANOTHER SHORTWAVE TROUGH MOVES THROUGH THE NORTHEAST THU NIGHT/FRI...WITH YET ANOTHER NEXT WEEKEND. AT THE SFC...HIGH PRES ENTRENCHED DOWN THE APPALACHIANS WILL WEAKEN AS AN INVERTED TROUGH DEVELOPS OFF THE EAST COAST. MODELS ARE VARYING WITH THE PRONUNCIATION OF THIS FEATURE AND HOW MUCH IT WILL IMPACT THE LOCAL AREA ON WED. FOR NOW HAVE SCHC POPS ACROSS THE EAST END ALTHOUGH SOME OF THIS SYSTEMS MOISTURE MAY BE INFUSED INTO AN APPROACHING COLD FRONT AND COULD PRODUCE SOME SHOWERS WELL OUT AHEAD OF IT. HAVE THE FRONT MOVING THROUGH LATE WED NIGHT/THU MORNING...CONSISTENT WITH A NAM/SREF BLEND AS STATED ABOVE. THE PROGRESSIVE FLOW DEVELOPING ALOFT WILL ALSO BE TRANSLATED TO THE SFC. WEAK HIGH PRES RETURNS IN THE WAKE OF THE FRONT WITH LOW PRES PASSING S OF LONG ISLAND THU NIGHT OR FRI. DRY CONDITIONS THEN RETURN AGAIN FRI NIGHT INTO SAT COURTESY OF HIGH PRES BUILDING TO OUR S...BUT A WAVE OF LOW PRES DEVELOPING OVER THE GULF COAST RIDES ALONG ANOTHER COLD FRONT MARCHING TOWARDS THE AREA NEXT WEEKEND. TEMPERATURES WILL START OFF 5 TO 10 DEGREES ABOVE NORMAL...BUT WILL GRADUALLY RETURN TO SEASONABLE LEVELS IN THE LOWER TO MID 60S DURING THE DAY AND 40S...AROUND 50 IN NYC...AT NIGHT NEXT WEEKEND. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL SETTLE OVER THE AREA TODAY. PATCHES OF MVFR CIGS CONTINUE...IMPACTING ABOUT HALF THE AREA. WILL CONTINUE TO MONITOR TRENDS. AMENDMENTS ARE LIKELY AS FORECASTING THESE CLOUDS REMAINS QUITE A CHALLENGE THIS MORNING. LIGHT NE FLOW SHOULD BECOME SE-S 5-10 KT BY AFTERNOON. IT IS UNCERTAIN EXACTLY WHERE THE HIGH PRESSURE RIDGE WILL BE ORIENTED BY LATE DAY...SO WIND DIRECTION FORECAST CONFIDENCE LOWERS LATE IN THE DAY. SPEEDS REMAIN LESS THAN 10 KT. SCT TO BROKEN CLOUDS 5 TO 10 KFT ARE ANTICIPATED LATE TODAY AND TONIGHT AS AN APPROACHING FRONTAL BOUNDARY WEAKENS. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: TIMING OF WIND SHIFT FROM NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO S/SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. KLGA FCSTER COMMENTS: TIMING OF WIND SHIFT FROM NE TO E/SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. KTEB FCSTER COMMENTS: CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. KHPN FCSTER COMMENTS: POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. KISP FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. OUTLOOK FOR 12Z TUE THROUGH FRI... .TUE...VFR. .TUE NIGHT...POSSIBLE SUB VFR IN STRATUS AND FOG. .WED-FRI...MVFR CONDITIONS POSSIBLE AT TIMES IN SCT SHOWERS. && .MARINE... THE SURFACE PRESSURE GRADIENT HAS WEAKENED AND WIND HAS DIMINISHED. THE PRESSURE GRADIENT CONTINUES TO WEAKEN THROUGH THE DAY. IN RESPONSE SEAS ON THE OCEAN WATERS HAVE FALLEN BELOW 5 FT. THE SMALL CRAFT FOR HAZARDOUS SEAS HAS BEEN CANCELLED. THEREAFTER WITH WEAK PRESSURE GRADIENTS IN PLACE...SUB SCA CONDITIONS WILL BE FORECAST GOING INTO MONDAY NIGHT AND TUESDAY. A RELATIVELY WEAK FLOW WILL REMAIN ACROSS THE WATERS THROUGH THE END OF THE WEEK RESULTING IN SUB-SCA CONDS. && .HYDROLOGY... DRY WEATHER IS FORECAST THROUGH TUESDAY. GENERALLY BETWEEN 1/4 AND 1/2 INCH OF RAINFALL IS EXPECTED WITH THE COLD FRONTAL PASSAGE LATE WED NIGHT/THU MORNING. NO HYDROLOGIC ISSUES ARE ANTICIPATED WITH THIS. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$
AREA FORECAST DISCUSSION
NWS NEW YORK NY
728 AM EDT MON OCT 14 2013 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE THROUGH TUESDAY...REMAINING GENERALLY NORTH AND EAST OF THE WATERS. THIS HIGH PRESSURE AREA WEAKENS TUESDAY NIGHT INTO WEDNESDAY AS IT SHIFTS INTO THE CANADIAN MARITIMES. AS HIGH PRESSURE MOVES OUT TO SEA...WEAK LOW PRESSURE WILL DEVELOP OFF THE EAST COAST WHILE A FRONTAL SYSTEM APPROACHES FROM THE GREAT LAKES. THIS SYSTEMS COLD FRONT WILL MOVE ACROSS THE AREA LATE WEDNESDAY NIGHT OR THURSDAY MORNING. WAVES OF LOW PRESSURE ARE THEN FORECAST TO IMPACT THE AREA FRIDAY AND SATURDAY NIGHT. ANOTHER COLD FRONT MOVES THROUGH LATE SATURDAY NIGHT INTO SUNDAY MORNING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LOWERED CLOUDS FOR EASTERN HALF OF REGION AS WELL AS LOWERED TEMPERATURES WITH VASTLY DIFFERENT RADIATIONAL COOLING BECAUSE OF THE PATCHY CLOUD COVERAGE. OTHER THAN THAT...FORECAST MAINLY ON TRACK. PATCHY FOG WILL DISSIPATE WITH DIURNAL WARMING THIS MORNING ACROSS THE INTERIOR AND RURAL AREAS. HIGH PRESSURE REMAINS STRONG...ESPECIALLY NORTH AND EAST OF THE LOCAL REGION. ALOFT...A RIDGE WILL REMAIN DOMINANT WITH ITS BASE TO OUR SOUTH. A COLD FRONT ASSOCIATED WITH AN EQUIVALENT BAROTROPIC LOW IN EASTERN CANADA WILL WEAKEN THROUGH THE DAY WITH EASTWARD MOVEMENT. THE LOSS OF TEMPERATURE ADVECTIONS WILL CONTRIBUTE TO THE WEAKENING OF THIS SYSTEM AND INHERENTLY RESULTING IN THE FRONTOLYSIS. THE ONLY EFFECT OF THE FRONT WILL BE AN INCREASE IN THE MOISTURE IN THE 700 TO 850 MB COLUMN LATE THIS AFTERNOON. THE LOWEST INVERSION AROUND 900MB GOING INTO THIS MORNING IS SHOWN TO MIX OUT BUT THE ONE AROUND 700 TO 800MB WILL REMAIN ALLOWING FOR MOISTURE TO COLLECT HERE. THIS IS WHERE CLOUDS WILL DEVELOP. THERE IS UNCERTAINTY ON EXACTLY HOW MUCH CLOUDS THERE WILL BE AND THE TIMING OF THE HIGHER CLOUD COVERAGE AND THIS IS ONE PARAMETER THAT COULD FLUCTUATE WITH SUBSEQUENT FORECASTS. THE NAM AND RUC BUFKITS INDICATE THIS POSSIBILITY BUT DIFFER ON THE TIMING WHILE THE GFS BUFKITS DOES NOT MOISTEN THE 700 TO 850MB LAYER BUT IS SLOWER TO MIX OUT THE LOWEST INVERSION AROUND 900MB WITH ITS CLOUDS THIS MORNING. THE RESULTING UNCERTAINTY WAS THE REASON WHY AN EQUAL BLEND OF MAV AND MET GUIDANCE WAS CHOSEN FOR HIGH TEMPERATURES TODAY...WHICH ARE FORECAST TO BE IN THE MID TO UPPER 60S FOR A MAJORITY OF THE REGION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... HIGH PRESSURE WILL REMAIN DOMINANT TONIGHT WITH A WEAK COLD FRONT APPROACHING FROM THE WEST AND DISSIPATING. ONLY EXPECTING AN INCREASE IN CLOUDS FROM THIS WITHIN THE 700-850MB LAYER FROM WEST TO EAST. THERE IS A LITTLE HIGHER CONFIDENCE ON MORE CLOUDS TONIGHT. HENCE...LOWS WERE PREFERRED WITH A 3/4 MET WARMER GUIDANCE TO 1/4 COOLER MAV GUIDANCE. WILL KEEP FORECAST ON THE SLOWER SIDE WITH PROGRESSION OF CLOUDS CONSIDERING THE LOWERING BOUNDARY LAYER FLOW AND LACK OF WINDS TO MIX DOWN. THIS WILL RESULT IN MORE CLOUDS FOR TONIGHT. GOING WITH A WARMER DAY TUESDAY AS THE RIDGE SHIFTS EAST AND THERE IS MORE OF A SOUTHWEST FLOW ALOFT. THERE IS SOME PRETTY GOOD LOW LEVEL WARM ADVECTION TOO WITH THE SOUTHEAST FLOW AT 850MB VEERING TO THE SOUTHWEST FLOW AT 700MB. THE WINDS ARE SLIGHTLY MORE THAN THE PREVIOUS DAY. HIGH TEMPS WERE A BLEND OF THE WARMER MET 2/3 AND COOLER 1/3 MAV CONSIDERING THE WARM AIR ADVECTION. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... UPPER LEVEL RIDGE AXIS WILL SLIDE E OF THE AREA BY WED EVE WITH A TROUGH TRACKING TOWARDS THE AREA FROM THE GREAT LAKES/OHIO VALLEY REGION. THERE ARE TIMING DIFFERENCES WITH THE PROGRESSION OF THIS FIRST TROUGH WHICH HAS A RIPPLE EFFECT ON LATER PERIODS. THE GFS/GEFS MEAN IS FASTEST...FOLLOWED CLOSELY BY THE EC AND SREF...THEN THE NAM AND CMC AND LASTLY THE UKMET. HAVE STUCK WITH A MIDDLE OF THE ROAD SOLN...NAM/SREF BLEND UNTIL THIS IS BETTER RESOLVED. MEANWHILE...A BROAD UPPER LEVEL TROUGH WILL BE CARVED OUT THROUGH CENTRAL NOAM. A PROGRESSIVE PATTERN WILL DEVELOP ACROSS THE EASTERN US IN RESPONSE TO A TIGHT SW FLOW ALOFT. ANOTHER SHORTWAVE TROUGH MOVES THROUGH THE NORTHEAST THU NIGHT/FRI...WITH YET ANOTHER NEXT WEEKEND. AT THE SFC...HIGH PRES ENTRENCHED DOWN THE APPALACHIANS WILL WEAKEN AS AN INVERTED TROUGH DEVELOPS OFF THE EAST COAST. MODELS ARE VARYING WITH THE PRONUNCIATION OF THIS FEATURE AND HOW MUCH IT WILL IMPACT THE LOCAL AREA ON WED. FOR NOW HAVE SCHC POPS ACROSS THE EAST END ALTHOUGH SOME OF THIS SYSTEMS MOISTURE MAY BE INFUSED INTO AN APPROACHING COLD FRONT AND COULD PRODUCE SOME SHOWERS WELL OUT AHEAD OF IT. HAVE THE FRONT MOVING THROUGH LATE WED NIGHT/THU MORNING...CONSISTENT WITH A NAM/SREF BLEND AS STATED ABOVE. THE PROGRESSIVE FLOW DEVELOPING ALOFT WILL ALSO BE TRANSLATED TO THE SFC. WEAK HIGH PRES RETURNS IN THE WAKE OF THE FRONT WITH LOW PRES PASSING S OF LONG ISLAND THU NIGHT OR FRI. DRY CONDITIONS THEN RETURN AGAIN FRI NIGHT INTO SAT COURTESY OF HIGH PRES BUILDING TO OUR S...BUT A WAVE OF LOW PRES DEVELOPING OVER THE GULF COAST RIDES ALONG ANOTHER COLD FRONT MARCHING TOWARDS THE AREA NEXT WEEKEND. TEMPERATURES WILL START OFF 5 TO 10 DEGREES ABOVE NORMAL...BUT WILL GRADUALLY RETURN TO SEASONABLE LEVELS IN THE LOWER TO MID 60S DURING THE DAY AND 40S...AROUND 50 IN NYC...AT NIGHT NEXT WEEKEND. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL SETTLE OVER THE AREA TODAY. PATCHES OF MVFR CIGS CONTINUE...IMPACTING ABOUT HALF THE AREA. WILL CONTINUE TO MONITOR TRENDS. AMENDMENTS ARE LIKELY AS FORECASTING THESE CLOUDS REMAINS QUITE A CHALLENGE THIS MORNING. LIGHT NE FLOW SHOULD BECOME SE-S 5-10 KT BY AFTERNOON. IT IS UNCERTAIN EXACTLY WHERE THE HIGH PRESSURE RIDGE WILL BE ORIENTED BY LATE DAY...SO WIND DIRECTION FORECAST CONFIDENCE LOWERS LATE IN THE DAY. SPEEDS REMAIN LESS THAN 10 KT. SCT TO BROKEN CLOUDS 5 TO 10 KFT ARE ANTICIPATED LATE TODAY AND TONIGHT AS AN APPROACHING FRONTAL BOUNDARY WEAKENS. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: TIMING OF WIND SHIFT FROM NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO S/SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. KLGA FCSTER COMMENTS: TIMING OF WIND SHIFT FROM NE TO E/SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. KTEB FCSTER COMMENTS: CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. KHPN FCSTER COMMENTS: POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. KISP FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING AROUND OR JUST UNDER 3 KFT AT TIMES THIS MORNING. OUTLOOK FOR 12Z TUE THROUGH FRI... .TUE...VFR. .TUE NIGHT...POSSIBLE SUB VFR IN STRATUS AND FOG. .WED-FRI...MVFR CONDITIONS POSSIBLE AT TIMES IN SCT SHOWERS. && .MARINE... SEAS ARE ON A SLOW DECLINE WITH WAVE HEIGHTS. HOWEVER...THERE IS STILL A 8 SEC EASTERLY SWELL WHICH WILL ENABLE FOR THE FURTHER DECREASES IN WAVE HEIGHT TO BE RATHER SLOW. WAVEWATCH IS ALSO NOW RUNNING A LITTLE LOW IN TERMS OF THE WAVE HEIGHT AT BUOY 44025. THE PRESSURE GRADIENT WILL WEAKEN CONSIDERABLY GOING INTO THE DAY SO THE SMALL CRAFT WAS CONVERTED TO ONE JUST FOR HAZARDOUS SEAS. GUSTS WILL BE LOWERING WITH CURRENT GUSTS ONLY UP TO 20 KT ON THE OCEAN. THE TIMING IS SUCH THAT THE OCEAN WEST OF MORICHES INLET WILL HAVE SMALL CRAFT CONDITIONS UNTIL 18Z WHILE EAST OF THERE...IT REMAINS UNTIL 16Z. THEREAFTER WITH WEAK PRESSURE GRADIENTS IN PLACE...SUB SCA CONDITIONS WILL BE FORECAST GOING INTO MONDAY NIGHT AND TUESDAY. A RELATIVELY WEAK FLOW WILL REMAIN ACROSS THE WATERS THROUGH THE END OF THE WEEK RESULTING IN SUB-SCA CONDS. && .HYDROLOGY... DRY WEATHER IS FORECAST THROUGH TUESDAY. GENERALLY BETWEEN 1/4 AND 1/2 INCH OF RAINFALL IS EXPECTED WITH THE COLD FRONTAL PASSAGE LATE WED NIGHT/THU MORNING. NO HYDROLOGIC ISSUES ARE ANTICIPATED WITH THIS. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ353-355. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON EDT TODAY FOR ANZ350. && $$ SYNOPSIS...24/JM NEAR TERM...JM SHORT TERM...JM LONG TERM...24 AVIATION...PW MARINE...24/JM HYDROLOGY...24/JM EQUIPMENT...
AREA FORECAST DISCUSSION
NWS NEW YORK NY
706 AM EDT MON OCT 14 2013 .SYNOPSIS... HIGH PRESSURE WILL DOMINATE THROUGH TUESDAY...REMAINING GENERALLY NORTH AND EAST OF THE WATERS. THIS HIGH PRESSURE AREA WEAKENS TUESDAY NIGHT INTO WEDNESDAY AS IT SHIFTS INTO THE CANADIAN MARITIMES. AS HIGH PRESSURE MOVES OUT TO SEA...WEAK LOW PRESSURE WILL DEVELOP OFF THE EAST COAST WHILE A FRONTAL SYSTEM APPROACHES FROM THE GREAT LAKES. THIS SYSTEMS COLD FRONT WILL MOVE ACROSS THE AREA LATE WEDNESDAY NIGHT OR THURSDAY MORNING. WAVES OF LOW PRESSURE ARE THEN FORECAST TO IMPACT THE AREA FRIDAY AND SATURDAY NIGHT. ANOTHER COLD FRONT MOVES THROUGH LATE SATURDAY NIGHT INTO SUNDAY MORNING. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LOWERED CLOUDS FOR EASTERN HALF OF REGION AS WELL AS LOWERED TEMPERATURES WITH VASTLY DIFFERENT RADIATIONAL COOLING BECAUSE OF THE PATCHY CLOUD COVERAGE. OTHER THAN THAT...FORECAST MAINLY ON TRACK. PATCHY FOG WILL DISSIPATE WITH DIURNAL WARMING THIS MORNING ACROSS THE INTERIOR AND RURAL AREAS. HIGH PRESSURE REMAINS STRONG...ESPECIALLY NORTH AND EAST OF THE LOCAL REGION. ALOFT...A RIDGE WILL REMAIN DOMINANT WITH ITS BASE TO OUR SOUTH. A COLD FRONT ASSOCIATED WITH AN EQUIVALENT BAROTROPIC LOW IN EASTERN CANADA WILL WEAKEN THROUGH THE DAY WITH EASTWARD MOVEMENT. THE LOSS OF TEMPERATURE ADVECTIONS WILL CONTRIBUTE TO THE WEAKENING OF THIS SYSTEM AND INHERENTLY RESULTING IN THE FRONTOLYSIS. THE ONLY EFFECT OF THE FRONT WILL BE AN INCREASE IN THE MOISTURE IN THE 700 TO 850 MB COLUMN LATE THIS AFTERNOON. THE LOWEST INVERSION AROUND 900MB GOING INTO THIS MORNING IS SHOWN TO MIX OUT BUT THE ONE AROUND 700 TO 800MB WILL REMAIN ALLOWING FOR MOISTURE TO COLLECT HERE. THIS IS WHERE CLOUDS WILL DEVELOP. THERE IS UNCERTAINTY ON EXACTLY HOW MUCH CLOUDS THERE WILL BE AND THE TIMING OF THE HIGHER CLOUD COVERAGE AND THIS IS ONE PARAMETER THAT COULD FLUCTUATE WITH SUBSEQUENT FORECASTS. THE NAM AND RUC BUFKITS INDICATE THIS POSSIBILITY BUT DIFFER ON THE TIMING WHILE THE GFS BUFKITS DOES NOT MOISTEN THE 700 TO 850MB LAYER BUT IS SLOWER TO MIX OUT THE LOWEST INVERSION AROUND 900MB WITH ITS CLOUDS THIS MORNING. THE RESULTING UNCERTAINTY WAS THE REASON WHY AN EQUAL BLEND OF MAV AND MET GUIDANCE WAS CHOSEN FOR HIGH TEMPERATURES TODAY...WHICH ARE FORECAST TO BE IN THE MID TO UPPER 60S FOR A MAJORITY OF THE REGION. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... HIGH PRESSURE WILL REMAIN DOMINANT TONIGHT WITH A WEAK COLD FRONT APPROACHING FROM THE WEST AND DISSIPATING. ONLY EXPECTING AN INCREASE IN CLOUDS FROM THIS WITHIN THE 700-850MB LAYER FROM WEST TO EAST. THERE IS A LITTLE HIGHER CONFIDENCE ON MORE CLOUDS TONIGHT. HENCE...LOWS WERE PREFERRED WITH A 3/4 MET WARMER GUIDANCE TO 1/4 COOLER MAV GUIDANCE. WILL KEEP FORECAST ON THE SLOWER SIDE WITH PROGRESSION OF CLOUDS CONSIDERING THE LOWERING BOUNDARY LAYER FLOW AND LACK OF WINDS TO MIX DOWN. THIS WILL RESULT IN MORE CLOUDS FOR TONIGHT. GOING WITH A WARMER DAY TUESDAY AS THE RIDGE SHIFTS EAST AND THERE IS MORE OF A SOUTHWEST FLOW ALOFT. THERE IS SOME PRETTY GOOD LOW LEVEL WARM ADVECTION TOO WITH THE SOUTHEAST FLOW AT 850MB VEERING TO THE SOUTHWEST FLOW AT 700MB. THE WINDS ARE SLIGHTLY MORE THAN THE PREVIOUS DAY. HIGH TEMPS WERE A BLEND OF THE WARMER MET 2/3 AND COOLER 1/3 MAV CONSIDERING THE WARM AIR ADVECTION. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... UPPER LEVEL RIDGE AXIS WILL SLIDE E OF THE AREA BY WED EVE WITH A TROUGH TRACKING TOWARDS THE AREA FROM THE GREAT LAKES/OHIO VALLEY REGION. THERE ARE TIMING DIFFERENCES WITH THE PROGRESSION OF THIS FIRST TROUGH WHICH HAS A RIPPLE EFFECT ON LATER PERIODS. THE GFS/GEFS MEAN IS FASTEST...FOLLOWED CLOSELY BY THE EC AND SREF...THEN THE NAM AND CMC AND LASTLY THE UKMET. HAVE STUCK WITH A MIDDLE OF THE ROAD SOLN...NAM/SREF BLEND UNTIL THIS IS BETTER RESOLVED. MEANWHILE...A BROAD UPPER LEVEL TROUGH WILL BE CARVED OUT THROUGH CENTRAL NOAM. A PROGRESSIVE PATTERN WILL DEVELOP ACROSS THE EASTERN US IN RESPONSE TO A TIGHT SW FLOW ALOFT. ANOTHER SHORTWAVE TROUGH MOVES THROUGH THE NORTHEAST THU NIGHT/FRI...WITH YET ANOTHER NEXT WEEKEND. AT THE SFC...HIGH PRES ENTRENCHED DOWN THE APPALACHIANS WILL WEAKEN AS AN INVERTED TROUGH DEVELOPS OFF THE EAST COAST. MODELS ARE VARYING WITH THE PRONUNCIATION OF THIS FEATURE AND HOW MUCH IT WILL IMPACT THE LOCAL AREA ON WED. FOR NOW HAVE SCHC POPS ACROSS THE EAST END ALTHOUGH SOME OF THIS SYSTEMS MOISTURE MAY BE INFUSED INTO AN APPROACHING COLD FRONT AND COULD PRODUCE SOME SHOWERS WELL OUT AHEAD OF IT. HAVE THE FRONT MOVING THROUGH LATE WED NIGHT/THU MORNING...CONSISTENT WITH A NAM/SREF BLEND AS STATED ABOVE. THE PROGRESSIVE FLOW DEVELOPING ALOFT WILL ALSO BE TRANSLATED TO THE SFC. WEAK HIGH PRES RETURNS IN THE WAKE OF THE FRONT WITH LOW PRES PASSING S OF LONG ISLAND THU NIGHT OR FRI. DRY CONDITIONS THEN RETURN AGAIN FRI NIGHT INTO SAT COURTESY OF HIGH PRES BUILDING TO OUR S...BUT A WAVE OF LOW PRES DEVELOPING OVER THE GULF COAST RIDES ALONG ANOTHER COLD FRONT MARCHING TOWARDS THE AREA NEXT WEEKEND. TEMPERATURES WILL START OFF 5 TO 10 DEGREES ABOVE NORMAL...BUT WILL GRADUALLY RETURN TO SEASONABLE LEVELS IN THE LOWER TO MID 60S DURING THE DAY AND 40S...AROUND 50 IN NYC...AT NIGHT NEXT WEEKEND. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... HIGH PRESSURE WILL SETTLE OVER THE AREA TODAY. PATCHES OF MVFR CIGS CONTINUE...IMPACTING ABOUT HALF THE AREA. WILL CONTINUE TO MONITOR TRENDS. AMENDMENTS ARE LIKELY AS FORECASTING THESE CLOUDS REMAINS QUITE A CHALLENGE THIS MORNING. LIGHT E-NE FLOW SHOULD BECOME SE-S 5-10 KT BY AFTERNOON. IT IS UNCERTAIN EXACTLY WHERE THE HIGH PRESSURE RIDGE WILL BE ORIENTED BY LATE DAY...SO WIND DIRECTION FORECAST CONFIDENCE LOWERS LATE IN THE DAY. SPEEDS REMAIN LESS THAN 10 KT. SCT TO BROKEN CLOUDS 5 TO 10 KFT ARE ANTICIPATED LATE TODAY AND THROUGH THE EVENING AS AN APPROACHING FRONTAL BOUNDARY WEAKENS. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KEWR FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO S/SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KLGA FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KTEB FCSTER COMMENTS: POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KHPN FCSTER COMMENTS: POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. KISP FCSTER COMMENTS: TIMING OF WIND SHIFT FROM E/NE TO SE MAY BE OFF BY AN HOUR OR TWO. POSSIBLE CEILING UNDER 3 KFT AT TIMES THIS MORNING. OUTLOOK FOR 06Z TUE THROUGH FRI... .TONIGHT-TUE...VFR. .WED-FRI...MVFR CONDS POSSIBLE AT TIMES IN SCT SHOWERS. && .MARINE... SEAS ARE ON A SLOW DECLINE WITH WAVE HEIGHTS. HOWEVER...THERE IS STILL A 8 SEC EASTERLY SWELL WHICH WILL ENABLE FOR THE FURTHER DECREASES IN WAVE HEIGHT TO BE RATHER SLOW. WAVEWATCH IS ALSO NOW RUNNING A LITTLE LOW IN TERMS OF THE WAVE HEIGHT AT BUOY 44025. THE PRESSURE GRADIENT WILL WEAKEN CONSIDERABLY GOING INTO THE DAY SO THE SMALL CRAFT WAS CONVERTED TO ONE JUST FOR HAZARDOUS SEAS. GUSTS WILL BE LOWERING WITH CURRENT GUSTS ONLY UP TO 20 KT ON THE OCEAN. THE TIMING IS SUCH THAT THE OCEAN WEST OF MORICHES INLET WILL HAVE SMALL CRAFT CONDITIONS UNTIL 18Z WHILE EAST OF THERE...IT REMAINS UNTIL 16Z. THEREAFTER WITH WEAK PRESSURE GRADIENTS IN PLACE...SUB SCA CONDITIONS WILL BE FORECAST GOING INTO MONDAY NIGHT AND TUESDAY. A RELATIVELY WEAK FLOW WILL REMAIN ACROSS THE WATERS THROUGH THE END OF THE WEEK RESULTING IN SUB-SCA CONDS. && .HYDROLOGY... DRY WEATHER IS FORECAST THROUGH TUESDAY. GENERALLY BETWEEN 1/4 AND 1/2 INCH OF RAINFALL IS EXPECTED WITH THE COLD FRONTAL PASSAGE LATE WED NIGHT/THU MORNING. NO HYDROLOGIC ISSUES ARE ANTICIPATED WITH THIS. && .EQUIPMENT... DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM. DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE INTERFERENCE ISSUE HAS BEEN RESOLVED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 2 PM EDT THIS AFTERNOON FOR ANZ353-355. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON EDT TODAY FOR ANZ350. && $$ SYNOPSIS...24/JM NEAR TERM...JM SHORT TERM...JM LONG TERM...24 AVIATION...PW MARINE...24/JM HYDROLOGY...24/JM EQUIPMENT...
AREA FORECAST DISCUSSION
NWS TOPEKA KS
652 AM CDT Mon Oct 14 2013 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 403 AM CDT MON OCT 14 2013 Confidence on the specifics of when and where best coverage of precipitation will be over the next 24 hours is not high, but the overall setup is for a widespread wet event over much of the Central Plains. 00Z upper jet structure showed southern branch from central Baja into Kansas with northern branch south and east around the Great Basin upper low then northeast into the Four Corners, and this will push east through tonight with persistent diffluence over Kansas resulting. Deep moisture will steadily increase with stronger mid level flow initially leading to better isentropic lift there (ongoing in central portions of the state) and then somewhat lower as the day progresses and 850 mb winds increase to near 60 kt around 00Z. Elevated creeps up as well for an increasing thunder concern pushing east with time. Have generally indicated the most likely wet periods from mid morning through early evening from west to east, close to the WRF-ARW and recent HRRR runs which seem to be handling the overnight convection the best. They are also similar with surface-based storms breaking out in the KHLC vicinity in the late afternoon hours as the mid level dry slot works northeast and cold front surges east. With plenty of shear, CAPE will be the main limiting factor with this activity maintaining itself through north central Kansas, but at least minor concern for severe hail and wind potential exist in western areas. Cold front sweeps through overnight with clearing and drying taking over. High temperature details are also difficult with onset and duration of daytime precip and continued late-day south winds coinciding with some potential dry periods in the west possibly leading to max values around 0Z. .LONG TERM...(Tuesday through Sunday) Issued at 403 AM CDT MON OCT 14 2013 Drier air will move into eastern Kansas in the wake of the frontal boundary and upper level system on Tuesday. Surface high pressure will build into eastern Kansas Tuesday night and Wednesday keeping winds rather light and temperatures below normal. GFS and ECMWF move an upper trough across the plains Wednesday and Wednesday night. Forecast soundings show dry air in the low and mid levels will be present keeping chances of any measurable precipitation to the south of the CWA. Cannot rule out a few sprinkles south of I-35 though. Models continue to offer differing solutions for Friday through the weekend. The ECMWF has been inconsistent while the GFS has been more consistent on a run to run basis. The ECMWF is much sharper and further south with the mid level trough while the GFS maintains a ridge in the eastern Pacific and northwest flow across the Plains with a broad upper low over Ontario into the Ohio Valley through the weekend. However the ECMWF brings another shortwave trough across Kansas Saturday. Given the differences in the models and limited moisture availability, will go with a dry forecast at this time and will wait and see what later model runs provide. Highs will mainly be in the 60s with lows in the 30s and 40s. && .AVIATION...(For the 12Z TAFs through 12Z Tuesday Morning) Issued at 652 AM CDT MON OCT 14 2013 Radar trends not far off from short range models with convection becoming more widespread near and upstream of the terminals. Only made a few alterations to going forecast, delaying initial onset of nearby TSRA but then going down to MVFR conditions in especially low clouds a bit earlier. Cold front sweeps through late in the forecast with VFR conditions returning. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...53 AVIATION...65
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1030 AM EDT MON OCT 14 2013 .SYNOPSIS... A WEAKENING COLD FRONT WILL MOVE ACROSS THE REGION THIS AFTERNOON INTO THIS EVENING. ANOTHER AREA OF HIGH PRESSURE WILL APPROACH FROM THE WEST TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... 1030 AM UPDATE...HAVE SENT ANOTHER QUICK UPDATE TO INCREASE POPS ACROSS THE NORTH THIS MORNING, AS A BATCH OF LIGHT TO OCCASIONALLY MODERATE RAIN IS MAKING ITS WAY EASTWARD ACROSS AROOSTOOK COUNTY. ALSO BUMPED UP POPS TO 40-50% IN CENTRAL MAINE AS THE HRRR AND RUC/RAP CONTINUE TO SHOW A BAND OF RAIN MAKING IN THERE THIS AFTERNOON. GIVEN THE LOW CLOUDS AND FOG THAT STILL PLAGUE NORTHERN MAINE, ALSO TWEAKED HIGH TEMPS DOWN A COUPLE OF DEGREES, AS WELL. NO OTHER CHANGES NEEDED. PREVIOUS DISCUSSION...HIGH PRESSURE IS CURRENTLY DRIFTING TO THE SOUTH OF THE STATE AS A WEAK COLD FRONT APPROACHES FROM THE WEST. THE COLD FRONT IS EXPECTED TO MOVE THROUGH DURING THE DAY MONDAY. THIS MAY RESULT IN SOME SHOWERS OVER THE WESTERN AREAS BUT EXPECT THE FRONT TO WEAK AS IT MOVES THROUGH. FOR POPS AND QPF HAVE BLENDED THE NAM12 GFS40 ...SREF AND THE ECMWF. TEMPERATURE AND DEW POINT GRIDS GENERATED WITH THE BIAS CORRECTED CONSENSUS ALL. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... HIGH PRES WILL MOVE ACROSS THE REGION ON TUESDAY AND PASS OFF TO THE E ON WEDNESDAY. A FRONTAL SYSTEM WILL MOVE TOWARD THE REGION ON WEDNESDAY W/INCREASING CLOUDS AND SHOWERS BY LATER IN THE DAY. AOA NORMAL DAYTIME TEMPERATURES ARE EXPECTED FOR TUESDAY W/SUN AND CLOUDS. STAYED PRETTY CLOSE TO THE DAYCREW`S ASSESSMENT OF UPPER 50S TO AROUND 60 NORTH AND WEST AND LOWER 60S CENTRAL AND DOWNEAST. WEDNESDAY LOOKS TO A MOSTLY CLOUDY DAY FOR THE MOST PART W/THE RISK FOR SHOWERS BY THE AFTERNOON ESPECIALLY FOR THE WESTERN AREAS AS WELL AS THE INTERIOR DOWNEAST AND THE COAST WHERE THE BEST FORCING WILL BE SITUATED. THE LATEST RUNS OF THE GFS AND ECMWF ARE IN VERY GOOD AGREEMENT W/THIS SETUP AS NOW IS THE CANADIAN GLOBAL. THEREFORE, CHANGES WERE MADE TO THE PRECIP CHANCES ESPECIALLY ACROSS THE DOWNEAST AND COAST(RAISED TO 60%) AS A DISTURBANCE LIFTS NORTHWARD AHEAD OF THE APCHG FRONTAL BOUNDARY TO THE WEST. THERE DOES APPEAR TO BE ENOUGH MID LEVEL FORCING(700 MBS) TO SUPPORT THE RAMP UP IN THE PRECIP CHANCES. NORTH-CENTRAL AREAS COULD ACTUALLY GET AWAY RAIN FREE UNTIL WEDNESDAY EVENING AS THIS REGION WILL BE BETWEEN THE 2 FEATURES. TEMPERATURES ON WEDNESDAY ARE FCST TO BE MORE IN LINE W/NORMAL READINGS FOR MID OCTOBER. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... PRECIP CHANCES WILL INCREASE WEDNESDAY NIGHT ON INTO THURSDAY AS THE FRONTAL BOUNDARY MOVES ACROSS THE REGION FROM THE WEST. CONFIDENCE IS HIGH ENOUGH TO RAISE THE PRECIP CHANCES UP TO 60-70% W/STRONG LLVL CONVERGENCE AND GOOD MID LEVEL FORCING. THE DECISION WAS TO KEEP THE WX ELEMENT AS RAIN FOR THIS FCST CYCLE FOLLOWING THE DAYCREW`S LEAD. THERE IS SOME CONCERN FOR POSSIBLE CONVECTION LATER WEDNESDAY NIGHT INTO EARLY THURSDAY. THE ECMWF AND GFS SHOW DECENT LLVL WARMING TAKING HOLD FOR THIS TIMEFRAME W/SOME DECENT UPPER LEVEL DIFLUENCE. THE 00Z RUN OF THE ECMWF IS MORE PRONOUNCED W/THIS SETUP THAN THE 00Z GFS. THE CANADIAN GLOBAL TO SOME EXTENT INDICATED THIS AS WELL. THE DRAWBACK IS TWO FOLD. ONE IS THAT THE LLVLS WILL BE STABLE DUE TO A SSE FLOW AND TWO, THE MODELS ESPECIALLY THE GFS, HAVE BACKED AWAY FROM THE CONVECTIVE POTENTIAL(SUCH AS SBCAPE AND TOTAL TOTALS) THAT THEY WERE SHOWING 24 HR AGO. THEREFORE, DECIDED TO LEAVE THE MENTION OF TSTMS OUT FOR THIS CYCLE AND WOULD LIKE TO SEE HOW THINGS UNFOLD AS WE CLOSE IN ON THE EVENT. THE OVERALL PATTERN LOOKS LIKE IT WILL CONTINUE TO BE PROGRESSIVE AS THIS SYSTEM WILL MOVE ON OUT OF THE CWA BY THURSDAY NIGHT W/PARTIAL CLEARING SLATED FOR FRIDAY. MUCH COOLER WEATHER IS EXPECTED BEHIND THIS SYSTEM W/DAYTIME TEMPERATURES ON FRIDAY ACTUALLY NEAR NORMAL. THIS COOLER WEATHER IS EXPECTED TO CONTINUE RIGHT INTO THE WEEKEND W/ANOTHER FRONTAL BOUNDARY FCST TO BRING SOME SHOWERS ON SATURDAY. STAYED CLOSE TO THE DAYCREW`S ASSESSMENT OF NEAR NORMAL TEMPERATURES INTO THE WEEKEND. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... NEAR TERM: MVFR/IFR IN FOG THIS MORNING THEN VFR CONDITIONS EXPECTED TODAY AND TONIGHT. SHORT TERM: VFR INTO EARLY WEDNESDAY AND THEN CONDITIONS ARE FCST TO DROP TO MVFR WEDNESDAY AFTERNOON AND THEN IFR WEDNESDAY NIGHT INTO THURSDAY FOR ALL TERMINALS. LIFR CONDITIONS ARE POSSIBLY ESPECIALLY ON THURSDAY W/THE FROPA. && .MARINE... NEAR TERM: HAVE USED THE NAM12 TO GENERATE SUSTAINED WIND GRIDS. FOR WAVES: WITH HIGH PRESSURE OVER THE WATERS EXPECT LIGHT WINDS EARLY TODAY WITH PRIMARY SEAS CONSISTING OF SOUTHERLY LONG PERIOD WAVES AROUND 2 FEET/8 SECONDS. WAVE MODEL SPECTRA DEPICTING THIS GROUP WELL ALTHOUGH GROUP WAVE HEIGHTS ARE A LITTLE LOW ON 0000Z WAVE WATCH RUN. LATER TODAY SOUTHERLY WIND WAVE (1-2 FEET/3-4 SECONDS) COMBINES WITH SWELL AND PERSISTS INTO TONIGHT. SHORT TERM: NO HEADLINES ANTICIPATED. WINDS WILL PICK IN ADVANCE OF THE APCHG FRONTAL SYSTEM ON THURSDAY AND DECIDED TO BRING SUSTAINED WINDS TO 10-15 KTS. WAVE HEIGHTS AREA FCST TO CLIMB TO 5 FT W/THE POTENTIAL FOR A SWELL AHEAD OF THE FRONT. THERE IS THE POSSIBILITY THAT THE SWELL COULD REACH 6 FT OVER THE OUTER WATERS BY LATER WEDNESDAY IN THAT SWELL. ATTM, KEPT WAVE HEIGHTS AT 5 FT AND THIS SURGE LOOKS TO BE SHORT LIVED. STILL TIME TO ASSESS THIS W/THE LATER GUIDANCE. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HASTINGS/MIGNONE SHORT TERM...HEWITT LONG TERM...HEWITT AVIATION...HASTINGS/MIGNONE/HEWITT MARINE...HASTINGS/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
912 AM EDT MON OCT 14 2013 .SYNOPSIS... A WEAKENING COLD FRONT WILL MOVE ACROSS THE REGION THIS AFTERNOON INTO THIS EVENING. ANOTHER AREA OF HIGH PRESSURE WILL APPROACH FROM THE WEST TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... 910 AM UDATE...FOG IS STARTING TO SLOWLY LIFT THIS MORNING, THOUGH WE ARE STILL SOCKED IN HERE IN CARIBOU AND A FEW OTHER LOCATIONS ACROSS NORTHERN AROOSTOOK COUNTY. HOWEVER, MOST OF THE DENSE FOG HAS LIFTED, SO ALLOWED THE DENSE FOG ADVISORY TO EXPIRE AT 9 AM. THE OTHER CONCERN FOR THIS UPDATE IS THE SHOWERS THAT ARE ASSOCIATED WITH AN APPROACHING COLD FRONT. THE LATEST HI-RES MODELS, INCLUDING THE HRRR AND RUC/RAP, INDICATE THAT THE BATCH OF RAIN CURRENTLY MOVING ACROSS VERMONT AND NORTHERN NEW YORK WILL MOVE NEARLY DIRECTLY EAST INTO CENTRAL AND PORTIONS OF DOWNEAST MAINE BY THIS AFTERNOON. HAVE UPDATED POPS ACCORDINGLY, INTRODUCING ISOLATED/SCATTERED SHOWERS IN THESE AREAS. WILL HAVE TO WATCH RADAR TRENDS CAREFULLY, AS THESE RAIN CHANCES MAY HAVE TO BE EXTENDED EVEN FURTHER SOUTH IN LATER UPDATES. REGARDLESS, DON`T EXPECT MUCH MORE THAN A TENTH OF AN INCH TO FALL IN MOST SPOTS, THOUGH ISOLATED HIGHER AMOUNTS ARE POSSIBLE ACROSS THE HIGHER TERRAIN IN THE NORTH MAINE WOODS. PREVIOUS DISCUSSION...HIGH PRESSURE IS CURRENTLY DRIFTING TO THE SOUTH OF THE STATE AS A WEAK COLD FRONT APPROACHES FROM THE WEST. THE COLD FRONT IS EXPECTED TO MOVE THROUGH DURING THE DAY MONDAY. THIS MAY RESULT IN SOME SHOWERS OVER THE WESTERN AREAS BUT EXPECT THE FRONT TO WEAK AS IT MOVES THROUGH. FOR POPS AND QPF HAVE BLENDED THE NAM12 GFS40 ...SREF AND THE ECMWF. TEMPERATURE AND DEW POINT GRIDS GENERATED WITH THE BIAS CORRECTED CONSENSUS ALL. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... HIGH PRES WILL MOVE ACROSS THE REGION ON TUESDAY AND PASS OFF TO THE E ON WEDNESDAY. A FRONTAL SYSTEM WILL MOVE TOWARD THE REGION ON WEDNESDAY W/INCREASING CLOUDS AND SHOWERS BY LATER IN THE DAY. AOA NORMAL DAYTIME TEMPERATURES ARE EXPECTED FOR TUESDAY W/SUN AND CLOUDS. STAYED PRETTY CLOSE TO THE DAYCREW`S ASSESSMENT OF UPPER 50S TO AROUND 60 NORTH AND WEST AND LOWER 60S CENTRAL AND DOWNEAST. WEDNESDAY LOOKS TO A MOSTLY CLOUDY DAY FOR THE MOST PART W/THE RISK FOR SHOWERS BY THE AFTERNOON ESPECIALLY FOR THE WESTERN AREAS AS WELL AS THE INTERIOR DOWNEAST AND THE COAST WHERE THE BEST FORCING WILL BE SITUATED. THE LATEST RUNS OF THE GFS AND ECMWF ARE IN VERY GOOD AGREEMENT W/THIS SETUP AS NOW IS THE CANADIAN GLOBAL. THEREFORE, CHANGES WERE MADE TO THE PRECIP CHANCES ESPECIALLY ACROSS THE DOWNEAST AND COAST(RAISED TO 60%) AS A DISTURBANCE LIFTS NORTHWARD AHEAD OF THE APCHG FRONTAL BOUNDARY TO THE WEST. THERE DOES APPEAR TO BE ENOUGH MID LEVEL FORCING(700 MBS) TO SUPPORT THE RAMP UP IN THE PRECIP CHANCES. NORTH-CENTRAL AREAS COULD ACTUALLY GET AWAY RAIN FREE UNTIL WEDNESDAY EVENING AS THIS REGION WILL BE BETWEEN THE 2 FEATURES. TEMPERATURES ON WEDNESDAY ARE FCST TO BE MORE IN LINE W/NORMAL READINGS FOR MID OCTOBER. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... PRECIP CHANCES WILL INCREASE WEDNESDAY NIGHT ON INTO THURSDAY AS THE FRONTAL BOUNDARY MOVES ACROSS THE REGION FROM THE WEST. CONFIDENCE IS HIGH ENOUGH TO RAISE THE PRECIP CHANCES UP TO 60-70% W/STRONG LLVL CONVERGENCE AND GOOD MID LEVEL FORCING. THE DECISION WAS TO KEEP THE WX ELEMENT AS RAIN FOR THIS FCST CYCLE FOLLOWING THE DAYCREW`S LEAD. THERE IS SOME CONCERN FOR POSSIBLE CONVECTION LATER WEDNESDAY NIGHT INTO EARLY THURSDAY. THE ECMWF AND GFS SHOW DECENT LLVL WARMING TAKING HOLD FOR THIS TIMEFRAME W/SOME DECENT UPPER LEVEL DIFLUENCE. THE 00Z RUN OF THE ECMWF IS MORE PRONOUNCED W/THIS SETUP THAN THE 00Z GFS. THE CANADIAN GLOBAL TO SOME EXTENT INDICATED THIS AS WELL. THE DRAWBACK IS TWO FOLD. ONE IS THAT THE LLVLS WILL BE STABLE DUE TO A SSE FLOW AND TWO, THE MODELS ESPECIALLY THE GFS, HAVE BACKED AWAY FROM THE CONVECTIVE POTENTIAL(SUCH AS SBCAPE AND TOTAL TOTALS) THAT THEY WERE SHOWING 24 HR AGO. THEREFORE, DECIDED TO LEAVE THE MENTION OF TSTMS OUT FOR THIS CYCLE AND WOULD LIKE TO SEE HOW THINGS UNFOLD AS WE CLOSE IN ON THE EVENT. THE OVERALL PATTERN LOOKS LIKE IT WILL CONTINUE TO BE PROGRESSIVE AS THIS SYSTEM WILL MOVE ON OUT OF THE CWA BY THURSDAY NIGHT W/PARTIAL CLEARING SLATED FOR FRIDAY. MUCH COOLER WEATHER IS EXPECTED BEHIND THIS SYSTEM W/DAYTIME TEMPERATURES ON FRIDAY ACTUALLY NEAR NORMAL. THIS COOLER WEATHER IS EXPECTED TO CONTINUE RIGHT INTO THE WEEKEND W/ANOTHER FRONTAL BOUNDARY FCST TO BRING SOME SHOWERS ON SATURDAY. STAYED CLOSE TO THE DAYCREW`S ASSESSMENT OF NEAR NORMAL TEMPERATURES INTO THE WEEKEND. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... NEAR TERM: MVFR/IFR IN FOG THIS MORNING THEN VFR CONDITIONS EXPECTED TODAY AND TONIGHT. SHORT TERM: VFR INTO EARLY WEDNESDAY AND THEN CONDITIONS ARE FCST TO DROP TO MVFR WEDNESDAY AFTERNOON AND THEN IFR WEDNESDAY NIGHT INTO THURSDAY FOR ALL TERMINALS. LIFR CONDITIONS ARE POSSIBLY ESPECIALLY ON THURSDAY W/THE FROPA. && .MARINE... NEAR TERM: HAVE USED THE NAM12 TO GENERATE SUSTAINED WIND GRIDS. FOR WAVES: WITH HIGH PRESSURE OVER THE WATERS EXPECT LIGHT WINDS EARLY TODAY WITH PRIMARY SEAS CONSISTING OF SOUTHERLY LONG PERIOD WAVES AROUND 2 FEET/8 SECONDS. WAVE MODEL SPECTRA DEPICTING THIS GROUP WELL ALTHOUGH GROUP WAVE HEIGHTS ARE A LITTLE LOW ON 0000Z WAVE WATCH RUN. LATER TODAY SOUTHERLY WIND WAVE (1-2 FEET/3-4 SECONDS) COMBINES WITH SWELL AND PERSISTS INTO TONIGHT. SHORT TERM: NO HEADLINES ANTICIPATED. WINDS WILL PICK IN ADVANCE OF THE APCHG FRONTAL SYSTEM ON THURSDAY AND DECIDED TO BRING SUSTAINED WINDS TO 10-15 KTS. WAVE HEIGHTS AREA FCST TO CLIMB TO 5 FT W/THE POTENTIAL FOR A SWELL AHEAD OF THE FRONT. THERE IS THE POSSIBILITY THAT THE SWELL COULD REACH 6 FT OVER THE OUTER WATERS BY LATER WEDNESDAY IN THAT SWELL. ATTM, KEPT WAVE HEIGHTS AT 5 FT AND THIS SURGE LOOKS TO BE SHORT LIVED. STILL TIME TO ASSESS THIS W/THE LATER GUIDANCE. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...HASTINGS/MIGNONE SHORT TERM...HEWITT LONG TERM...HEWITT AVIATION...HASTINGS/MIGNONE/HEWITT MARINE...HASTINGS/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
733 AM EDT MON OCT 14 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 527 AM EDT MON OCT 14 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED MID LEVEL LOW LIFTING NE ACROSS HUDSON BAY WITH A TROF EXTENDING SW INTO THE ROCKIES WHERE ANOTHER SHORTWAVE WAS LOCATED OVER UT/CO. THIS SHORTWAVE WILL BEGIN TO AFFECT THE UPPER GREAT LAKES LATER TODAY AND TONIGHT AS IT LIFTS NE. BTWN THE SYSTEMS OVER HUDSON BAY AND THE ROCKIES...SHORTWAVE RIDGING IS SUPPORTING SFC HIGH PRES OVER THE WRN GREAT LAKES EARLY THIS MORNING. EXCELLENT RADIATIONAL COOLING CONDITIONS DURING THE NIGHT HAVE ALLOWED TEMPS TO FALL INTO THE MID 20S TO LWR 30S ACROSS MUCH OF THE INTERIOR OF UPPER MI. HERE AT NWS MQT...THE TEMP SO FAR AS OF 09Z HAS FALLEN TO 30F...MAKING THIS THE FIRST NIGHT THIS AUTUMN WITH A MIN TEMP AT OR BLO FREEZING. THIS TIES 1997 FOR THE LATEST OCCURRENCE OF THE FIRST MIN TEMP AT OR BLO FREEZING IN AUTUMN. SFC HIGH PRES OVER THE AREA WILL SLOWLY MOVE E TODAY WHILE SHORTWAVE OVER THE ROCKIES LIFTS NE INTO THE WRN PLAINS. FORCING ASSOCIATED WITH WAVE WILL REMAIN WELL W AND SW OF HERE TODAY. HOWEVER...RIGHT ENTRANCE OF STRENGTHENING UPPER JET ACROSS NRN ONTARIO/SRN MANITOBA WILL BRING INCREASING UPPER DIVERGENCE OVER THE UPPER MISSISSIPPI VALLEY. UPPER DIVERGENCE ASSOCIATED WITH THE JET IS ALREADY AIDING SOME BANDS OF -SHRA ACROSS ND INTO NW MN EARLY THIS MORNING PER RADAR IMAGERY THOUGH NOT ALL OF IT IS REACHING THE GROUND. THRU LATE AFTN...PLACEMENT OF THE UPPER JET OVER NRN ONTARIO/SRN MANITOBA WILL LEAD TO BEST UPPER DIVERGENCE REMAINING W OF THE FCST AREA AS DOES ISENTROPIC ASCENT AT THE LOWER LEVELS. IN ADDITION...DRY AIR MASS OVER THE AREA (SIMILAR TO 00Z KINL SOUNDING) WILL TAKE SOME TIME TO SATURATE...ESPECIALLY SINCE MAIN MOISTURE TRANSPORT REMAINS TO THE W OVER MN. THUS...PLAN TO MAINTAIN DRY WEATHER ACROSS UPPER MI TODAY...BUT WILL BRING CHC POPS INTO WRN LAKE SUPERIOR MID/LATE AFTN AS ERN FRINGE OF PCPN AREA MAY MAKE SOME PROGRESS INTO DRIER AIR. OTHERWISE...EXPECT A SLOW/STEADY INCREASE IN HIGH/MID CLOUDS THRU THE DAY FROM W TO E AS CLOUDS SPREAD DOWNWIND FROM THE UPPER DIVERGENCE/ISENTROPIC ASCENT AREA TO THE W. GUIDANCE IS WELL CLUSTERED ON MAX TEMPS TODAY...GENERALLY MID/UPPER 50S. AS UPPER JET TO THE N LIFTS SLIGHTLY N AND E...THERE SHOULD BE AN AREA OF -SHRA THAT SHIFTS ACROSS WRN AND NRN LAKE SUPERIOR TONIGHT...PROBABLY TO THE N OF UPPER MI. MEANWHILE...SHORTWAVE OVER THE WRN PLAINS WILL LIFT TO SE SD/SW MN/NW IA BY 12Z TUE WITH HEALTHY FORCING NOTED BY DEEP LAYER QVECTORS SPREADING TOWARD UPPER MI LATE. COMBINED WITH STRONG MOISTURE TRANSPORT AND STRONG ISENTROPIC ASCENT NOTED ON THE 300K SFC...EXPECT SHRA TO ADVANCE NE INTO WRN UPPER MI OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 426 AM EDT MON OCT 14 2013 MODELS ARE IN DECENT GENERAL AGREEMENT THROUGH THE EXTENDED...BUT LACK AGREEMENT ON SPECIFIC DETAILS /ESPECIALLY FOR TUE-WED/ THAT LEADS TO A MORE UNCERTAIN FORECAST. A NEARLY STACKED LOW PRESSURE SYSTEM WILL BE OVER FAR SW MN AT 12Z TUE...WITH WAA DRIVEN PRECIP OVER THE W AND CENTRAL CWA THROUGH TUE MORNING. AS THE SYSTEM MOVES OVER OR S OF THE CWA /DEPENDING OF MODEL SOLUTION/ THE TRACK OF THE LOW WILL BECOME MORE IMPORTANT AS A TROWAL WILL ACCOMPANY THE LOW. MODELS HAVE SLOWED THE SYSTEM DOWN A BIT FROM 24 HOURS AGO...AND THERE IS STILL DISAGREEMENT ON THE TIMING OF THE SYSTEM. THE 00Z/14 GFS AND 00Z/14 NAM ARE FASTER AND FARTHER N WITH THE TIMING/TRACK...WHICH MOVES THE TROWAL AND ASSOCIATED RAIN E FASTER ON WED. THE 12Z/13 GEM AND 12Z/13 ECMWF ARE SLOWER...BUT STILL DISAGREE ON THE EXACT TRACK. IF THE MORE SOUTHERN SOLUTION OF THE ECMWF VERIFIES...EVEN THOUGH IT IS SLOWER...RAIN WILL NOT LAST AS LONG ON WED AS EVEN THE GFS/NAM ARE SAYING SINCE THE TROWAL WOULD BE S/SE OF THE CWA WED AFTERNOON. THE SLOWER AND FARTHER N SOLUTION OF THE GEM WOULD RESULT IN THE LONGEST LASTING RAIN AS THE TROWAL STAYS OVER THE CWA INTO EARLY WED NIGHT. WILL CONTINUE TO LEAN TOWARD THE SLOWER SOLUTION GIVEN MODEL TRENDS IN THAT DIRECTION. WILL ALSO KEEP POPS HIGH TUE AND TUE NIGHT AS CONFIDENCE OFF AREA WIDE RAIN IS GOOD AT THAT TIME. FOR WED NIGHT INTO EARLY THU...MODELS GIVE A BRIEF REPRIEVE FROM TROUGHING AS A WEAK RIDGE MOVES OVERHEAD. AFTER THAT...A DEEP UPPER LOW WILL MOVE S FROM HUDSON BAY CLOSER TO THE INTERNATIONAL BORDER IN ONTARIO THROUGH SUN. THIS WILL BRING AN INCREASINGLY COLD AIRMASS OVERHEAD THROUGH AT LEAST THE WEEKEND. LOOKS LIKE A COLD FRONT WILL MOVE THROUGH ON THU...BUT PRECIP IS UNCERTAIN ALONG THE FRONT AS MODELS DISAGREE ON HOW MUCH SYNOPTIC FORCING WILL BE AVAILABLE FROM THE UPPER TROUGH MOVING INTO THE REGION. WILL NOT GO HIGHER THAN SLIGHT CHANCE POPS FOR THU. BY 00Z SAT...850MB TEMPS COOL TO AROUND -2C...SO EXPECT LAKE ENHANCED PRECIP ALONG A SECONDARY AND STRONGER COLD FRONT ON FRI GIVEN LAKE SFC TEMPS OF 9C TO 13C. MODELS THEN SHOW 850MB TEMPS DECREASING TO -5C TO -7C FRI NIGHT THROUGH SUN AS MULTIPLE ROUNDS OF UPPER LEVEL ENERGY MOVE THROUGH. WITH THESE COLDER TEMPS...EXPECT PURE LAKE EFFECT PRECIP WITH INCREASES IN INTENSITY WITH ENHANCEMENT FROM ANY CONTRIBUTING SYNOPTIC ENERGY. AS FOR PRECIP TYPE...SHOULD BE ABLE TO SEE ALL SNOW AT NIGHT/MORNING WHEN TEMPS ARE COOLEST FRI NIGHT THROUGH SUN MORNING...AND MAINLY OVER THE HIGHER TERRAIN. OTHERWISE...HIGH TEMPS WILL BE IN THE 40S SO SNOW IS NOT EXPECTED DURING THE WARMER DAYTIME HOURS. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED AT 731 AM EDT MON OCT 14 2013 VFR CONDITIONS WILL CONTINUE AT KIWD/KCMX/KSAW THRU THIS FCST PERIOD AS DRY AIR MASS LINGERS DESPITE EXITING HIGH PRES. HOWEVER...AS LOW PRES SYSTEM ORGANIZING OVER THE WRN PLAINS MOVES NE...SHRA WILL SPREAD NE AND WILL LIKELY REACH KIWD LATE TONIGHT. WITH AN E TO SE DOWNSLOPE WIND...CONDITIONS SHOULDN`T FALL BLO VFR UNTIL SEVERAL HRS AFTER PCPN BEGINS. SHOWERS AND DETERIORATING CONDITIONS ARE EXPECTED AT ALL 3 TERMINALS BEYOND THIS FCST PERIOD DURING THE DAY TUE. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 527 AM EDT MON OCT 14 2013 HIGH PRES OVER THE WRN LAKES WILL RESULT IN LIGHT WINDS ACROSS LAKE SUPERIOR...MOSTLY UNDER 15KT THRU MID AFTN. LATER TODAY AND TONIGHT...EASTERLY WINDS WILL BEGIN TO INCREASE FROM W TO E AS THE HIGH SHIFTS E AND LOW PRES LIFTS NE THRU THE PLAINS. BY TUE AFTN...E TO NE WINDS WILL BE INTO THE 20-30KT RANGE OVER WRN LAKE SUPERIOR. AS THE LOW MOVES ENE JUST TO THE S OF LAKE SUPERIOR TUE AFTN THRU WED MORNING...THESE STRONGER WINDS GENERALLY IN THE 20-30KT RANGE WILL SPREAD W TO E ACROSS THE REST OF LAKE SUPERIOR WHILE THE WINDS BACK NORTHERLY. IT`S NOT OUT OF THE QUESTION THAT THERE COULD BE A PERIOD OF GALES TUE NIGHT/WED MORNING ON THE BACKSIDE OF THE LOW. WINDS WILL THEN DIMINISH W TO E WED AFTN/NIGHT AS THE LOW MOVES FARTHER E AND A WEAK SFC HIGH PRES RIDGE ARRIVES. AT THIS TIME...IT APPEARS WINDS WILL MOSTLY BE AOB 20KT THU/FRI. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...TITUS AVIATION...ROLFSON MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
622 AM CDT MON OCT 14 2013 .AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK. NUMEROUS AVIATION CONCERNS DURING THE PERIOD. THIS IS SHAPING UP TO BE WET DAY WITH SHOWERS AND THUNDERSTORMS THROUGH AT LEAST THE FIRST 12 TO 15 HOURS OF THE FORECAST PERIOD. GUSTY SOUTHEAST WINDS AT ALL TAF SITES...BECOMING WEST IN THE LATTER HALF OF THE FORECAST...AND EVENTUALLY NORTHWEST TOWARD THE END OF THE PERIOD. CEILINGS EVENTUALLY BECOMING MVFR...AND POSSIBLY IFR AT KOFK. LOW LEVEL WIND SHEAR WILL ALSO BE AN ISSUE AT ALL TAF SITES THIS MORNING. DEWALD && .PREV DISCUSSION... /ISSUED 355 AM CDT MON OCT 14 2013/ DISCUSSION... MAIN FORECAST CHALLENGE IS TIMING THE RAIN TODAY THROUGH TUESDAY...AND DETERMINING RAINFALL AMOUNTS. AT 08Z...SHOWERS WITH A FEW THUNDERSTORMS WERE MOVING THROUGH PARTS OF NEBRASKA...THEN EXTENDED SOUTHWEST THROUGH COLORADO AND INTO NORTHERN NEW MEXICO. THIS AREA OF PRECIPITATION WAS IN RESPONSE TO A DEEP UPPER LOW SPINNING OVER UTAH PER WATER VAPOR IMAGERY. ASSOCIATED WITH THE LOW WAS AN IMPRESSIVE JET MAX OF AROUND 145 KNOTS AS INDICATED BY THE RAP MODEL ANALYSIS NEAR THE COLORADO- NEW MEXICO BORDER. NUMEROUS LIGHTNING STRIKES WERE NOTED WITHIN THIS PRECIPITATION AREA. THE SURFACE CYCLOGENESIS RESPONSE TO THE UPPER LOW WAS MAXIMIZED FROM SOUTHEAST WYOMING INTO SOUTHWEST SOUTH DAKOTA WHERE 3 HOURLY PRESSURE FALLS WERE 2-3MB. BASED ON THE 100 METER 500MB HEIGHT RISES ON THE BACK SIDE OF THE UPPER TROUGH...THE EXPECTED SCENARIO IS FOR THE UPPER LOW TO MOVE FROM UTAH INTO THE NEBRASKA PANHANDLE BY THIS AFTERNOON. THAT WILL PIVOT THE JET AXIS TO A MORE EAST-WEST ORIENTATION...POSITIONING IT ACROSS SOUTHEAST COLORADO-SOUTHERN KANSAS. EXPECT STRONG UPWARD FORCING DUE TO A COMBINATION OF: THE UPPER DIVERGENCE FROM THE LEFT FRONT EXIT REGION OF THE JET MAX...STRONG DPVA AHEAD OF THE UPPER LOW...ISENTROPIC LIFT IN THE WARM CONVEYER BELT REGION...AND CONTINUED SURFACE CYCLOGENESIS. ALL OF THIS POINTS TO A WELL-DEFINED EXTRATROPICAL CYCLONE PATTERN MOVING THROUGH THE PLAINS TODAY AND THIS EVENING...WITH A SURFACE COLD FRONT MOVING THROUGH EASTERN NEBRASKA AND SOUTHWEST IOWA TONIGHT. IN THESE SCENARIOS WE CAN PLAN ON SOMEWHAT HEAVY RAINS AHEAD OF THE LOW DURING THE DAY TODAY AND INTO THE EVENING...THEN THE DRY SLOT PUSHING INTO THE REGION OVERNIGHT TONIGHT. THEN AS THE UPPER LOW MOVES NORTHEAST OF THE REGION...SCATTERED SHOWERS SHOULD OCCUR ON THE BACK SIDE OF THE LOW IN THE DEFORMATION ZONE. RAINFALL AMOUNTS OF 2 INCHES WILL BE POSSIBLE NEAR THE SOUTH DAKOTA BORDER...WITH CLOSER TO 0.5 INCH NEAR THE MISSOURI BORDER...AND 1-1.5 INCHES NEAR I-80. THESE AMOUNTS ARE SUPPORTED BY FAIRLY GOOD MODEL AGREEMENT WITH THE OVERALL PATTERN AS WELL AS THE MODEL RAINFALL. THIS ACTIVE PATTERN SHOULD BE ACCOMPANIED BY A STRONG SOUTHERLY LOW LEVEL JET OF AROUND 60 KNOTS THIS AFTERNOON AND EVENING...THEN 40-45 KNOTS OUT OF THE NORTHWEST TUESDAY. THUNDERSTORMS THAT DEVELOP ON THE EASTERN EDGE OF THE DRY SLOT OVER SOUTH CENTRAL NEBRASKA THIS AFTERNOON/EVENING MAY BE QUITE STRONG AND COULD MOVE NORTHEAST INTO AREAS GENERALLY WEST AND SOUTH OF NORFOLK. BEHIND THE COLD FRONT...TEMPERATURES WILL BE ABOUT 10 DEGREES COLDER TUESDAY THAN TODAY WITH GUSTY NORTHWEST WINDS...CLOUDS...AND SCATTERED LIGHT SHOWERS ESPECIALLY IN NORTHEAST NEBRASKA. SURFACE HIGH PRESSURE MOVES IN WEDNESDAY WITH COOL/QUIET WEATHER. THE PATTERN OVER NORTH AMERICA SETTLES INTO A HIGH AMPLITUDE RIDGE ALONG THE WEST COAST WITH A BROAD LONGWAVE TROUGH FROM HUDSON BAY INTO THE SOUTHERN US...AND THIS KEEPS THE CENTRAL PLAINS IN A COOL NORTHWEST FLOW REGIME INTO NEXT WEEK. NIETFELD && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
607 AM CDT MON OCT 14 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 445 AM CDT MON OCT 14 2013 AN ACTIVE 24 HOURS WITH QUITE HIGH MEASURABLE RAIN CHANCES IS ALREADY UNDERWAY ACROSS THE CWA...WITH PLENTY OF FORECAST CHALLENGES RANGING FROM TRYING TO REFINE SHORT-TERM POPS...ASSESSING THE MAGNITUDE OF A POSSIBLE SEVERE WEATHER RISK THIS AFTERNOON-EARLY EVENING...DETERMINING THE EFFECTS OF WIDESPREAD CLOUD COVER/PRECIP ON HIGH TEMPS...AND ALSO TRYING TO DETERMINE HOW CLOSE ESPECIALLY THE NORTHWESTERN CWA MAY COME TO AT LEAST BRIEFLY FLIRTING WITH WIND ADVISORY CRITERIA TONIGHT IN THE WAKE OF THE PASSING LOW. 08Z OBJECTIVE SURFACE ANALYSIS REVEALS A GRADUALLY-TIGHTENING PRESSURE GRADIENT...BETWEEN A ROUGHLY 1031 MILLIBAR HIGH OVER THE GREAT LAKES...AND A 1006 LOW OVER NORTHEAST CO. AS A RESULT...SUSTAINED SOUTHEAST WINDS ACROSS MOST OF THE CWA AT THIS HOUR ARE AVERAGING AT LEAST 10-15 MPH WITH HIGHER GUSTS TO AROUND 20 MPH...ESPECIALLY IN THE WEST. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A VIGOROUS MID/UPPER LEVEL TROUGH PLOWING ACROSS THE ROCKIES...WITH ITS 500MB VORT MAX CURRENTLY SWINGING OVER THE 4-CORNERS AREA. UPPER LEVEL FLOW HAS BECOME INCREASINGLY DIFFLUENT OVER THE CENTRAL PLAINS AHEAD OF A 100+KT JET STREAK APPROACHING FROM SOUTHERN CO...AND FARTHER DOWN A 40-50KT SOUTHERLY LOW LEVEL JET IS EVIDENT AT 850MB...RIGHT OVER THE HEART OF CENTRAL/WESTERN NEB AND KS. MUCH AS EXPECTED FOR DAYS NOW...STOUT LOW-MID LEVEL MOISTURE ADVECTION ESPECIALLY EVIDENT IN THE 850-700MB LAYER HAS RESULTED IN A GRADUAL INCREASE IN SHOWER/THUNDERSTORM ACTIVITY WITHIN THE CWA DURING THE NIGHT. OF COURSE...ITS NOT RAINING EVERYWHERE AT ONCE...AND EARLIER ON MOST OF THE PRECIP WAS FOCUSED IN NORTHWESTERN COUNTIES...BUT OVER THE PAST FEW HOURS THE MAIN FOCUS HAS TRANSITIONED TO ROUGHLY THE EASTERN 1/2 OF THE CWA...WITH MUCH OF THE WEST IN AT LEAST A SHORT TERM LULL. ALTHOUGH ITS QUITE POSSIBLE THAT A FEW OF THE STRONGER STORMS EARLY THIS MORNING HAVE PRODUCED/COULD PRODUCE VERY SMALL HAIL...NOT EXPECTING ANY SEVERE STORMS GIVEN MUCAPE IN THE 850-700MB LAYER ONLY AVERAGING A FEW HUNDRED J/KG PER LATEST RAP- BASED MESOANALYSIS. NOT SURPRISINGLY...TEMPS HAVE BEEN FAIRLY STEADY EARLY THIS MORNING UNDER WHAT HAS BECOME WIDESPREAD LOW CLOUD COVER AND SLOWLY-INCREASING DEWPOINTS...WITH MOST ALL PLACES CURRENTLY SOMEWHERE IN THE 50S. FOCUSING ON THE DAYTIME HOURS TODAY THROUGH 00Z/7PM...TOOK A BEST STAB AT 3-HOURLY POP TRENDS...BUT THE BOTTOM LINE IS THAT THE ENTIRE CWA IS SPORTING AN 80-90 PERCENT CHANCE OF MEASURABLE RAIN THROUGH SUNSET...ITS JUST A MATTER OF WHEN IT FALLS AND HOW MUCH FALLS. IN THE BIG PICTURE...THE PRIMARY 500MB VORT MAX ASSOCIATED WITH THE INCOMING TROUGH IS SCHEDULED TO REACH THE NEB PANHANDLE BY MID-DAY AS IT DEEPENS AND SWINGS NORTHEAST IN A NEGATIVELY TILTED FASHION...AND THEN REACHING FAR NORTH CENTRAL NEB BY AROUND SUNSET. IN SUIT...THE ASSOCIATED SURFACE LOW CURRENTLY CENTERED IN NORTHEAST CO IS PROGGED TO SHIFT NORTHEAST AS WELL...BUT SLIGHTLY SOUTHEAST OF THE MID LEVEL LOW TRACK...MEANING THAT IT GENERALLY SKIRTS JUST ALONG THE FAR WEST-CENTRAL/NORTHWEST EDGES OF THE CWA AS IT TRACKS NORTHEAST INTO NORTH CENTRAL NEB BY SUNSET WITH A CENTRAL PRESSURE AROUND 1003MB. MEANWHILE...A STOUT 50+KT LOW LEVEL JET WILL PERSIST OVER THE CWA PRETTY MUCH ALL DAY...WHICH IN TANDEM WITH CONTINUED LOW-MID LEVEL THETA-E ADVECTION SHOULD PROMOTE RATHER WIDESPREAD SHOWERS AND AT LEAST ISOLATED TO SCATTERED EMBEDDED THUNDERSTORMS THROUGH MUCH OF THE DAY. ITS YET TO BE SEEN WHETHER THIS WIDESPREAD PRECIPITATION MAINLY STAYS FOCUSED ACROSS THE EASTERN HALF OF THE CWA AS CURRENTLY HAPPENING...OR EVENTUALLY ALSO DEVELOPS OVER...OR MOVES INTO WESTERN AREAS AS WELL. MODELS VARY...WITH SOME ENDING THE LULL OVER THE WEST BY MID-MORNING...WHILE OTHERS SUCH AS THE LATEST HRRR CONTINUE TO FOCUS ON EASTERN AREAS AT LEAST THROUGH MID-DAY. AT ANY RATE...WOULD BE QUITE SURPRISED IF ANY OF THE CWA GOT THROUGH THE ENTIRE DAY WITHOUT MEASURABLE RAIN...AS MANY EASTERN AREAS COULD EASILY RECEIVE 0.50-0.75 INCH OR MORE THROUGH SUNSET. TURNING TO THE AFTERNOON HOURS...AS HAS ALSO BEEN ADVERTISED FOR A FEW DAYS NOW WE ARE FACING A CONDITIONAL SEVERE WEATHER THREAT...AS SPC HAS THE MAJORITY OF THE CWA IN A DAY 1 SLIGHT RISK AREA. THE MILLION DOLLAR QUESTION HERE IS...HOW MUCH CLEARING WILL TAKE PLACE JUST WEST OF...AND POSSIBLY INTO THE FAR SOUTHWESTERN PORTIONS OF THE CWA THIS AFTERNOON UNDER THE INVADING MID LEVEL DRY SLOT AND JUST AHEAD OF THE INVADING COLD FRONT/DRYLINE COMBO...TO PROMOTE SUFFICIENT DESTABILIZATION FOR SEVERE STORMS. FOLLOWING THE LEAD OF THE LATEST RAP...THE VAST MAJORITY OF THE CWA WILL REMAIN LOCKED UNDER LOW CLOUDS AND SCATTERED TO WIDESPREAD ELEVATED PRECIP THROUGH NEARLY THE ENTIRE DAY...WITH LIKELY NOTHING MORE THAN A HIT AND MISS THREAT OF SMALL HAIL POSSIBLY UP TO AROUND DIME SIZE. HOWEVER...BY MID-LATE AFTERNOON...THE RAP BRINGS A NARROW NORTH-SOUTH CORRIDOR OF LOW-LEVEL CAPE POTENTIALLY INTO THE 1000-1500 J/KG RANGE INTO MAINLY THE WESTERN 1/4 OF THE CWA. AS A RESULT...AND AS DEPICTED FAIRLY WELL BY THE 00Z RUNS OF THE 4KM WRF-NMM AND ARW AND ALSO THE LATEST HRRR...A LINE OF FAST MOVING STRONG TO POTENTIALLY SEVERE STORMS COULD SWEEP FROM WEST- EAST ACROSS MUCH OF THE CWA MAINLY BETWEEN 4PM-9PM...BUT LIKELY GRADUALLY LOSING STEAM AS IT DOES SO. ALTHOUGH LOW LEVEL SHEAR WILL BE STRONG...THUS MEANING THAT A BRIEF TORNADO THREAT IS NON- ZERO...EXPECT SYNOPTIC FORCING TO BE STRONG ENOUGH TO FORCE A LINEAR MODE FAIRLY QUICKLY...WITH THE MAIN THREAT BEING WINDS GUSTS TO AT LEAST 60 MPH...AND MAYBE SOME MARGINALLY SEVERE HAIL TO AROUND QUARTER SIZE. ALTHOUGH THE SPC SLIGHT RISK AREA COVERS NEARLY THE ENTIRE CWA...WILL BE FOCUSING THE LOCAL HAZARDOUS WEATHER OUTLOOK MAINLY ON THE SOUTHWEST HALF OF THE CWA...OR ROUGHLY SOUTHWEST OF A LOUP CITY-BELOIT LINE WHERE INSTABILITY SHOULD BE MAXIMIZED BEFORE IT DROPS OFF FARTHER EAST AS NIGHT FALLS. TURNING BRIEFLY TO OTHER ELEMENTS TODAY...HIGH TEMPERATURES WILL BE QUITE TRICKY AND OBVIOUSLY VERY DEPENDENT ON HOW MUCH PRECIP IS FALLING AND WHETHER ANY CLEARING TAKES PLACE IN THE SOUTHWEST...BUT BASED ON A VARIED BLEND OF SHORT TERM MODELS/GUIDANCE HAVE A RANGE FROM ONLY MID-UPPER 50S NORTH TO MID- UPPER 60S SOUTHWEST...WHICH IS A BIT COOLER THAN A STRAIGHT MET/MAV GUIDANCE BLEND AND COUNTS ON LOW CLOUDS HOLDING FIRM ACROSS MOST OF THE AREA. WIND-WISE TODAY...ALTHOUGH CERTAINLY QUITE BREEZY WITH SUSTAINED SOUTH-SOUTHEAST SPEEDS AVERAGING 20-25 MPH WITH GUSTS TO AROUND 30 MPH AHEAD OF THE APPROACHING COLD FRONT...NOT EXPECTING SUSTAINED SPEEDS TO BREACH ADVISORY CRITERIA OF 30+ MPH. TURNING TO THE TONIGHT PERIOD/7PM-7AM/...THE MAIN FOCUS IS ON HOW QUICKLY CONVECTION VACATES THE AREA...AND HOW STRONG WEST- NORTHWEST WINDS BECOME. ON THE BIG PICTURE...THERE IS GOOD AGREEMENT THAT THE CENTER OF THE CLOSED MID LEVEL LOW WILL ONLY SLOWLY MIGRATE FROM FAR NORTH CENTRAL NEB TO NEAR SIOUX FALLS...WHILE THE ATTENDANT SURFACE LOW FOLLOWS A SIMILAR PATH AND MAINTAINS A SIMILAR CENTRAL PRESSURE AROUND 1003MB. IN THE STOUT COLD AIR ADVECTION REGIME BEHIND THE DEPARTING LOW...AND IN AN ENHANCED PRESSURE GRADIENT BETWEEN THE SURFACE LOW AND AN EXPANSIVE HIGH NOSING INTO THE REGION FROM THE NORTHERN ROCKIES...ITS QUITE POSSIBLE THAT ESPECIALLY THE NORTHWEST HALF OF THE CWA MAY BE OVERALL-WINDIER TONIGHT THAN THEY ARE DURING THE DAY TODAY...EXCEPT THIS TIME OUT OF THE WEST-NORTHWEST BEHIND THE QUICKLY PASSING COLD FRONT...WHICH IS SLATED TO CRUISE ACROSS THE CWA GENERALLY BETWEEN 5-11PM. ALTHOUGH ITS NOT OUT OF THE QUESTION THAT THE LATEST SUITE OF MODELS/GUIDANCE ARE UNDER-DOING WIND SPEEDS A BIT...AT LEAST FOR NOW EXPECT SUSTAINED SPEEDS TO ONLY AVERAGE IN THE 20-25 MPH RANGE WITH GUSTS OF 30-35 MPH...AND THUS FALLING AT LEAST SLIGHTLY SHORT OF ADVISORY CRITERIA. NEIGHBORING OFFICES TO THE WEST HAVE ISSUED WIND HEADLINES FOR PORTIONS OF TODAY/TONIGHT...BUT AT THIS POINT JUST DON/T SEE THE LOCAL AREA BEING QUITE WINDY ENOUGH TO JUSTIFY AN ADVISORY...ALTHOUGH OF COURSE LATER SHIFTS WILL HAVE TO RE-EVALUATE THIS. OTHERWISE...IN TERMS OF PRECIP TRENDS...HAVE SLIGHTLY SPED UP THE DEPARTURE OF SHOWERS/STORMS...WITH MUCH OF THE WESTERN 1/2 OF THE CWA LIKELY DRIED OUT BY AROUND SUNSET...WHILE LIKELY POPS CONTINUE IN EASTERN COUNTIES THROUGH 02Z/9PM BEFORE QUICKLY DIMINISHING AND ENDING BY MIDNIGHT. ITS POSSIBLE THAT STORMS COULD CARRY AT LEAST A MARGINAL SEVERE THREAT UNTIL THEY DEPART EASTERN AREAS...BUT WOULD EXPECT THE MAIN THREAT TO DIMINISH POST-SUNSET. ALTHOUGH THE MAIN AREA OF PRECIP WILL VACATE THE AREA THIS EVENING...DID INTRODUCE A SLIGHT CHANCE OF LIGHT RAIN TO FAR NORTHERN ZONES THROUGH THE LATE EVENING/OVERNIGHT HOURS TO ACCOUNT FOR PRECIPITATION POSSIBLY BARELY BRUSHING THE CWA ON THE SOUTH-END OF THE WRAP-AROUND SHIELD. THE VAST MAJORITY OF THIS SHOULD FOCUS ACROSS FAR NORTHERN NEB HOWEVER. MADE LITTLE CHANGE TO OVERNIGHT LOWS...WITH MOST OF THE CWA BOTTOMING OUT IN THE 39-42 RANGE BY SUNRISE TUESDAY...ALTHOUGH ESPECIALLY THE NORTHWEST HALF OF THE AREA MAY BE HELD UP A BIT BY PLENTY OF LOW STRATUS WRAPPING BACK SOUTHWARD INTO THE AREA. THOSE VENTURING OUT LATE TONIGHT/EARLY TUESDAY WILL DEFINITELY NOTICE A BITE TO THE AIR...WITH WIND CHILL READINGS WELL DOWN INTO THE 30S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 445 AM CDT MON OCT 14 2013 PRIMARY CONCERNS WILL BE WINDY CONDITIONS ON TUESDAY AND LOW TEMPERATURES WITH FROST/FREEZE CHANCES ON WEDNESDAY AND THURSDAY MORNING. BUSY PATTERN STARTING OUT TUESDAY MORNING AS 500MB CLOSED LOW IS EXPECTED TO BE NEAR THE SDAK/MN BORDER WITH THE SYSTEM STACKED AS SURFACE LOW SHOULD BE JUST A TAD SOUTHEAST OF THE UPPER LOW POSITION. IN ADDITION TO THE UPPER LOW...TROUGHINESS IS EXPECTED TO EXTEND WESTWARD TOWARD THE CENTRAL ROCKIES. AS NOTED ABOVE...EXPECT WINDY CONDITIONS DURING THE DAYTIME TUESDAY AS WE SIT IN BETWEEN A WOUND UP SURFACE LOW NEAR THE MN/IA BORDER AND A STRONG HIGH PRESSURE BUILDING INTO CENTRAL WYOMING. THIS WILL RESULT IN A 20MB PRESSURE GRADIENT ACROSS NEBRASKA. SHOULD SEE SUSTAINED 25 MPH WINDS AT LEAST AND MAY BE APPROACHING ADVISORY CRITERIA ESPECIALLY IN THE NORTHERN HALF OF THE CWA FROM MID MORNING TO MID AFTERNOON. SOME LIGHT RAIN ALSO POSSIBLE ON TUESDAY IN THE NORTHERN QUARTER OF THE CWA WRAPPING AROUND THE LOW PRESSURE. IF WE DO GET ANY IT SHOULD NOT AMOUNT TO MUCH MORE THAN ONE OR TWO HUNDREDTHS. BY WEDNESDAY MORNING THE SURFACE LOW WILL HAVE MOVED INTO THE GREAT LAKES REGION WITH THE SURFACE HIGH BUILDING INTO OUR AREA. THIS WILL BRING LIGHTER WINDS AND ALSO EXPECTING SKIES TO CLEAR OUT...SO WITH DEWPOINTS IN THE UPPER 20S TO NEAR 30...MUCH OF THE CWA STANDS A DECENT CHANCE OF SEEING FROST WED MORNING. ON THURSDAY ANOTHER MID LEVEL WAVE WILL SLIDE ACROSS DRAGGING A COLD FRONT THROUGH THE CWA. DOESN`T APPEAR TO BE MUCH MOISTURE WITH THIS SYSTEM AND WILL KEEP FORECAST DRY. FRIDAY IS A LITTLE MORE INTERESTING AS A DEEP UPPER LOW SWINGS ACROSS CANADA AND THE NORTHERN PART OF THE U.S. THE EC MODELS BRINGS DOWN MUCH COLDER AIR THAN THE OPERATIONAL GFS. IT ALSO BRINGS A STRONG MID LEVEL WAVE DOWN THE BACKSIDE OF THE LOW ON FRIDAY AND GENERATES SOME MODERATE QPF WITH IT. THE GFS NOT SHOWING THIS AND THE GEM IS ALSO UNDERPLAYING THIS FEATURE. CHECKING THE ALL BLEND POPS...THEY ARE ONLY IN THE 15 TO 20 PERCENT RANGE FOR THE DAYTIME FRIDAY. BACK TO THE EC...IF ONE WERE TO ONLY LOOK AT 1000-500 MB THICKNESSES...THERE MAY BE CAUSE FOR CONCERN AS THE EC IS SHOWING THICKNESSES CONDUCIVE FOR SNOW. HOWEVER...A CLOSER EXAMINATION OF THE FORECAST SOUNDINGS FROM THE EC SHOWS SURFACE TEMPS IN THE UPPER 30S FRIDAY MORNING. ALSO THE GROUND SHOULD BE FAIRLY WARM SINCE HIGHS ON WED AND THURSDAY WILL BE NEAR 60. SO IF THE EC DOES VERIFY WITH THE MID LEVEL WAVE...WOULD EXPECT ANY PRECIP THAT OCCURS TO BE MORE OF A COLD RAIN. OF COURSE THIS WILL NEED TO BE MONITORED OVER THE NEXT FEW DAYS. && .AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z TUESDAY MORNING) ISSUED AT 606 AM CDT MON OCT 14 2013 A FAIRLY ACTIVE 24 HOURS OF WEATHER CONTINUES AT KGRI...WITH VARIOUS CONCERNS INCLUDING LOW LEVEL WIND SHEAR...SEVERAL HOURS OF PREVAILING MVFR CEILINGS WITH IFR NOT OUT OF THE QUESTION...GOOD CHANCES FOR PASSING SHOWERS/THUNDERSTORMS...AND FINALLY A PRONOUNCED WIND SHIFT BEHIND A COLD FRONT THIS EVENING. GOING ROUGHLY IN CHRONOLOGICAL ORDER WITH THESE ISSUES...HAVE EXTENDED A MENTION OF LOW LEVEL WIND SHEAR THROUGH 18Z...AS A STRONG LOW LEVEL JET STREAM WILL MAINTAIN AT LEAST A 30-40KT WIND VECTOR DIFFERENCE BETWEEN THE SURFACE AND ROUGHLY 1800 FT AGL...THANKS TO WINDS AT THE TOP OF THIS LAYER AVERAGING AROUND 50KT FROM THE SOUTH. SECONDLY...STRONG MOISTURE ADVECTION/LIFT SHOULD KEEP MVFR CEILINGS AROUND ALL DAY INTO THIS EVENING. HAVE KEPT OUT ANY IFR CEILING FOR NOW...BUT SOME MODEL GUIDANCE SUGGESTS IT IS ALSO POSSIBLE. THROUGH AROUND 03Z THIS EVENING...SCATTERED TO NUMEROUS SHOWERS/ISOLATED THUNDERSTORMS WILL CONTINUE...AND AM ADVERTISING EITHER VCSH/VCTS OR OUTRIGHT PREVAILING -SHRA THROUGH THE FIRST 15 HOURS OF THE PERIOD...BEFORE THERE IS FAIRLY HIGH CONFIDENCE THAT ANY RISK OF PRECIP ENDS THIS EVENING. SURFACE WINDS WILL REMAIN FAIRLY CONSISTENT FROM THE SOUTHEAST AT SUSTAINED SPEEDS 15-20KT WITH GUST POTENTIAL TO AT LEAST 26KT THROUGH THE DAYTIME HOURS...BEFORE AN ABRUPT SWITCH TO WESTERLY WINDS OCCURS AROUND SUNSET AS THE COLD FRONT PASSES...WITH GUST POTENTIAL CONTINUING TO AT LEAST 26KT WELL INTO THE NIGHT. WILL ALSO RAISE CEILING BACK INTO LOW-END VFR TERRITORY BEHIND THIS FRONT...AND SKIES COULD OUTRIGHT CLEAR FOR A TIME...VARYING DEGREES OF LOW LEVEL STRATUS COULD STICK AROUND THROUGH THE NIGHT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...EWALD AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
639 AM EDT MON OCT 14 2013 .SYNOPSIS... STALLED SURFACE FRONT NEAR OHIO RIVER TODAY. FRONT WASHES OUT TUESDAY. A STRONGER COLD FRONT MOVES THROUGH WEDNESDAY. POST FRONTAL DISTURBANCE RACES THROUGH LATE THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... WASHED OUT/STALLED SURFACE FRONT...REALLY MORE A WEAK PRESSURE TROUGH AT THIS POINT...RUNS FROM JUST WEST OF CKB TO JUST EAST OF HTS. DO HAVE SOME SOME MORE ENHANCED ECHOS SHOWING UP ALONG OR JUST WEST OF THIS BOUNDARY...AND ALSO IN NORTH CENTRAL WV. UPPED TO SCATTERED SHOWERS IN THESE AREA THROUGH THE EARLY MORNING. RAP SHOWS AN ELONGATED VORT LOBE MOVING ACROSS CWA THIS MORNING...SO KEEP SOME ISOLATED TO SCATTERED SHOWERS IN THE OHIO RIVER VALLEY TRANSITIONING MORE TO THE NORTHERN MOUNTAINS THIS AFTERNOON. LOW LEVEL MOISTURE STILL STRUGGLES TO CLEAR OUT...SO THINK PLENTY OF CLOUDS AROUND TODAY...EXCEPT VERY WESTERN CWA WHERE SATELLITE SHOWS CLEAR SKIES ALREADY DRIFTING IN. VORT LOBE AND ASSOCIATED POPS SHOULD BE MOVING OUT OF NORTHERN MOUNTAINS LATE AFTERNOON INTO EVENING...WITH A PRECIP FREE FORECAST BY LATE TONIGHT. COOLED HIGHS JUST A BIT TODAY WITH ABUNDANCE OF CLOUDS AND STAYED NEAR TO JUST ABOVE THE WARMER MET FOR LOWS TONIGHT. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... AFTER A VERY STRANGE PATTERN OF LATE...WE FINALLY GET THE ATMOSPHERE MOVING AGAIN DURING THIS TUESDAY THROUGH THURSDAY NIGHT TIME PERIOD. SO SEVERAL FEATURES TO TIME. DRIER AIR AT 925 TO 850 MBS THAT IS OFF THE JERSEY COAST THIS PREDAWN SHOULD CONTINUE TO SNEAK BACK WSW AND REACH OUR MOUNTAINOUS COUNTIES FOR TUESDAY. SO EXPECTING LESS CLOUDS THERE DURING TUESDAY AFTERNOON...COMPARED TO SAY OUR OHIO COUNTIES. WARMEST DAY OF THE WEEK SHOULD BE TUESDAY. WITH THE 700 MB FLOW INCREASING IN THE LOWER OHIO VALLEY TUESDAY NIGHT. WAS JUST A BIT FASTER BRINGING BACK SOME CHANCE POPS FOR PREFRONTAL SHOWERS OVERNIGHT TUESDAY NIGHT IN THE WEST. ALSO...KEPT TEMPERATURES MILDER THAN MOST MOS GUIDANCE THERE. INITIAL TIMING OF FRONT IS THROUGH OUR OHIO RIVER VALLEY COUNTIES BY MIDDAY AND ACROSS THE MOUNTAINOUS COUNTIES BY SUNSET. SO...THE ONLY CHANGE WORTH MENTIONING WAS A BIT FASTER LOWERING POPS FROM WEST TO EAST. LEFT OUR FRONTAL POPS IN THE LIKELY RANGE...WAS NOT IMPRESSED ENOUGH TO RAISE TO CATEGORICAL. WITH THAT TIMING...LOWERED DAYTIME MAXIMUM TEMPERATURES A FEW DEGREES WEDNESDAY. WITH 850 TEMPERATURES DROPPING SOME 6 TO 8C OVERNIGHT WEDNESDAY NIGHT...HELD ONTO SOME POPS OVER THE MOUNTAIN COUNTIES...AS WE SQUEEZE OUT THE LOW LEVEL MOISTURE. YET...FURTHER WEST...AT LEAST PARTIAL CLEARING AS EVEN THE 850 MOISTURE THINS OUT. FOR THURSDAY AND THURSDAY NIGHT...THE MORE RECENT RUNS OF THE ECMWF HAVE COME AROUND TO WHAT THE GFS HAD BEEN ADVERTISING PREVIOUSLY. THE MID LEVEL DISTURBANCE RACES THROUGH HERE THURSDAY EVENING. MOISTURE INCREASES FOR THURSDAY AFTERNOON AND EVENING. SO HELD THURSDAY MORNING DRIER THAN OUR PREVIOUS FORECAST...BUT STILL INCREASED POPS THURSDAY AFTERNOON. THINK CLEARING WILL DEVELOP IN OUR WESTERN LOWLANDS THURSDAY NIGHT. WILL LOWER TEMPERATURES FOR DAWN FRIDAY...ESPECIALLY FOR SOUTHEAST OHIO...NORTHEAST KENTUCKY...AND SPILLING INTO A FEW RURAL AREAS OF WESTERN WEST VIRGINIA. HAVE SOME 35 TO 40 DEG TEMPERATURES THERE...WILL MENTION/ADD THE POSSIBILITY OF FROST IN A FEW SPOTS IN THE HAZARDOUS WEATHER POTENTIAL...BUT CURRENTLY DO NOT THINK IT WILL BE WIDESPREAD. && .LONG TERM /FRIDAY THROUGH SUNDAY/... MODELS ARE HAVING DISAGREEMENTS ON HANDLING A SOUTHERN STREAM SYSTEM ON THURSDAY IN THE SPLIT FLOW UPPER AIR PATTERN. ALL AGREE THAT A NORTHERN STREAM SHORT WAVE AND ASSOCIATED COLD FRONT WILL QUICKLY EXIT EARLY WEDNESDAY NIGHT...TAKING THE SHOWERS WITH IT. SOME COOLER AND DRIER AIR DOES FLOW IN BEHIND THIS FRONT WEDNESDAY NIGHT. THE BIG QUESTION BECOMES WHAT HAPPENS TO A CHUNK OF ENERGY LEFT OVER THE SOUTHERN ROCKIES AS IT GETS QUICKLY EJECTED BY ANOTHER NORTHERN STREAM SHORT WAVE DROPPING OUT OF WESTERN CANADA. WILL GO WITH PERSISTENCE IN OUR FORECAST AND ENOUGH MODEL CONSENSUS...USING LATEST GFS AND ECMWF MODELS AVAILABLE...WITH THIS SHORT WAVE LIFTING UP FAR ENOUGH WEST TO DRIVE SURFACE LOW PRESSURE NORTHEASTWARD FROM THE LOWER MISSISSIPPI VALLEY THRU THE MID ATLANTIC THURSDAY. THIS WILL BRING A SWATH OF RAIN ACROSS THE AREA THURSDAY...ESPECIALLY IN THE EAST. OTHERWISE...OUTSIDE A WEAK AND RATHER MOISTURE LIMITED COOL FRONT SATURDAY...HIGH PRESSURE WILL GENERALLY DOMINATE FRIDAY THRU THE WEEKEND. EXPECT TEMPERATURES TO BE A LITTLE BELOW NORMAL FOR THIS TIME OF YEAR...BUT NO SIGNIFICANT FREEZE/FROST OUTSIDE THE HIGHER ELEVATIONS OF THE WEST VIRGINIA IS EXPECTED THRU THE WEEKEND. && .AVIATION /10Z MONDAY THROUGH FRIDAY/... CURRENT OBS SHOW IFR CIGS ACROSS MUCH OF FORECAST AREA. AFTER SUNRISE WILL START TO SEE DECK SLOWLY BEGIN LIFTING...HOWEVER EXPECT MVFR CIGS TO LINGER THROUGH MOST OF THE MORNING. WILL SEE CLOUDS LIFTING TO VFR THROUGH THE AFTERNOON...WITH SOME ISOLATED SHOWERS DRIFTING EAST...MAINLY ACROSS THE NORTHERN CWA. LOW ENOUGH POPS TO LEAVE ANY MENTION OF PRECIP OUT OF TAF FOR NOW. DRIER AIR ARRIVES ACROSS THE EAST OVERNIGHT...SO HIT THE FOG PRETTY HARD FOR MOUNTAIN VALLEYS. SHOULD CLOUDS CLEAR UP FARTHER WEST...COULD GET FOG ACROSS LOWLANDS TOO...HOWEVER THINK ENOUGH CLOUDS WILL HANG AROUND AND REDUCE CHANCES OF THAT. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY... FORECAST CONFIDENCE: MEDIUM. ALTERNATIVE SCENARIOS: TIMING OF CIG CAT CHANGES ACROSS CWA MAY VARY. DENSITY AND TIMING OF FOG MAY VARY TONIGHT. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22 EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18 CRW CONSISTENCY M M L L H H H M M M M H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY M M H H H H H H H H H H EKN CONSISTENCY H H H H H H H H H H H H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY M H H H H H H H H H H H AFTER 12Z TUESDAY... IFR POSSIBLE IN CONVECTION WEDNESDAY WITH A COLD FRONT. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...KTB/MZ NEAR TERM...MZ SHORT TERM...KTB LONG TERM...JMV AVIATION...MZ
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1103 AM MDT MON OCT 14 2013 .UPDATE...BAND OF CONVECTION CONTINUES TO PUSH EAST ACROSS THE PLAINS. MEANWHILE ADDITIONAL SHOWERS WERE DEVELOPING AND SPREADING SOUTHWARD BEHIND THE COLD FRONT WHICH HAD MOVED THROUGH GREELEY AND FORT COLLINS AND WILL PUSH ACROSS MOST OF DENVER METRO BY NOON AND PALMER DIVIDE AROUND 1 PM. HAVE MADE FURTHER MINOR ADJUSTMENTS TO PUSH STORMS EAST ACROSS THE EASTERN PLAINS BY 1 PM AND THEN HAVE SCATTERED SHOWER REDEVELOPMENT BEHIND THE FRONT ALONG THE I-25 CORRIDOR AND FOOTHILLS. IN THE HIGH COUNTRY...OROGRAPHICS AND GOOD UPSTREAM MOISTURE WILL KEEP SNOW SHOWERS GOING THROUGH THE AFTERNOON WITH ANOTHER 1-3 INCHES ACCUMULATION. EXISTING HIGHLIGHTS LOOK GOOD AS NORTHERN MOUNTAIN AREAS HAVE ALREADY SEEN 2-7 INCHES...AND GENERALLY 1-3 IN THE I-70 CORRIDOR. SHOWERS ARE EXPECTED TO GRADUALLY DECREASE THIS EVENING...BUT OVERALL HAD TO INCREASE POPS AND SNOW AMOUNTS SLIGHTLY GIVEN THE UPSTREAM MOISTURE AND DECENT OROGRAPHIC FLOW IN PLACE AS WINDS GO NORTHWESTERLY. && .AVIATION...FRONT WILL REACH KDEN AND KBJC AROUND 1720Z-1730Z AND THEN KAPA ABOUT 1830Z. GUSTY NORTH/NORTHEAST WINDS UP TO 25-28KTS POSSIBLE ESPECIALLY WITH ANY ENHANCEMENT FROM SHOWER OUTFLOWS. SCATTERED RAIN SHOWERS WILL LIKELY REDEVELOP BEHIND THE FRONT SO FEEL TEMPO -SHRA LOOKS GOOD THIS AFTERNOON. MOST PRECIPITATION SHOULD BE ENDING THIS EVENING BEFORE TEMPERATURES GET COLD ENOUGH TO SUPPORT MUCH IF ANY SNOWFALL. BIGGER CONCERN IS NOW SHIFTING TO POTENTIAL OF LOW STRATUS CEILINGS DEVELOPING BEHIND THE FRONT GIVEN THE UPSTREAM OBSERVATIONS AND VERY LOW T/TD SPREADS IN WYOMING. AS LONG AS UPSLOPE COMPONENT IS IN PLACE...WE WILL LIKELY HAVE LOWER CEILINGS THAN EXISTING FORECAST SO LOWERING THEM IN THE TAFS FOR NOW. && .PREV DISCUSSION... /ISSUED 759 AM MDT MON OCT 14 2013/ UPDATE...CONVECTION INCLUDING THUNDERSTORMS BREAKING OUT ALONG THE FRONT RANGE. HAVE UPDATED FORECAST FOR HIGHER POPS THIS MORNING AND THUNDERSTORMS. AVIATION...FOG IS IN THE PROCESS OF BEING REPLACED BY A BAND OF CONVECTIVE SHOWERS AND ISOLATED THUNDERSTORMS. MOST OF THESE WILL BE MOVING THROUGH 14Z-16Z WITH PARTIAL CLEARING AND SOME IMPROVEMENT IN CEILINGS WITH FRONT. COULD SEE GUSTS TO AROUND 35 KTS WITH THOSE SHOWERS AND STORMS. STILL A CHANCE OF SHOWERS AFTER 16Z BUT LESS WIND WITH THOSE. PREV DISCUSSION... /ISSUED 409 AM MDT MON OCT 14 2013/ SHORT TERM...TODAY AND TONIGHT...AN UPPER LEVEL TROUGH CENTERED NEAR THE FOUR CORNERS WILL LIFT NORTHEAST THIS MORNING AND CLOSE OFF OVER THE NEBRASKA PAN HANDLE AROUND 18Z. STRONG LIFT AHEAD OF THE TROUGH WILL CONTINUE TO BRING RAIN AND MOUNTAIN SNOW TO NORTHWEST AND NORTH CENTRAL COLORADO. SOUTHWEST FLOW AHEAD OF THE TROUGH IS BRINGING DRY AIR TO NORTHEAST COLORADO THIS MORNING...THE DRY SLOT. A SURFACE LOW OVER NORTHEAST COLORADO WILL MOVE INTO NEBRASKA THIS MORNING. AS IT LIFTS NORTHEAST IT WILL PULL A COLD FRONT ACROSS COLORADO. EXPECT THE FRONT TO PUSH ACROSS NORTHEAST COLORADO DURING THE LATE MORNING HOURS AS INDICATED BY THE GFS AND ECMWF. THE NAM...RAP AND HRRR ARE ALL MUCH LATER SHOWING THE FRONT PUSHING THROUGH DURING THE MID AFTERNOON. NORMALLY THE QUICKER SOLUTION OF THE GFS/ECMWF PANS OUT. APPEARS THE GFS IS HANDLING THE SURFACE PATTERN BETTER AND EXPECT ITS FORECAST TO BE BETTER. FOR THE FRONT RANGE...WILL HAVE TO WAIT UNTIL THE FRONT PASSES THROUGH AND UPSLOPE DEVELOPS FOR SHOWERS TO FORM. MOST OF THE SHOWERS WILL BE LIGHT AND DO NOT EXPECT MUCH FOR PRECIPITATION AMOUNTS. BETTER OROGRAPHIC LIFT WILL PREVAIL THIS AFTERNOON OVER THE MOUNTAINS DUE TO NORTHWEST FLOW AND COLD AIR ADVECTION. WILL KEEP THE ADVISORY GOING THROUGH 00Z. BASED ON CURRENT RADAR AND SATELLITE...APPEARS THE NORTH CENTRAL MOUNTAINS WILL SEE 2 TO 5 INCHES OF SNOW THROUGH SUNRISE. OROGRAPHIC LIFT TODAY SHOULD PRODUCE ANOTHER 2 TO 4 INCHES OF SNOW. ANOTHER THING TO WATCH WITH THIS SYSTEM WILL BE STRONG WINDS ON THE EASTERN PLAINS. STRONG COLD AIR ADVECTION BEHIND BEHIND THE FRONT WILL HELP STRONGER WINDS ALOFT MIX DOWN. THIS COMBINED WITH A TIGHT PRESSURE GRADIENT WILL PRODUCE WIND GUSTS OF 45 TO 55 MPH...JUST BELOW HIGH WIND CRITERIA. SOME WEAK SHOWERS WILL REMAIN POSSIBLE TONIGHT...MAINLY BEFORE MIDNIGHT. MAY GET COLD ENOUGH FOR A FEW SNOW SHOWERS ALONG THE FRONT RANGE AFTER SUNSET...BUT NO ACCUMULATION IS EXPECTED. EVEN THOUGH PRECIPITATION IS EXPECTED TO END...CLOUDY SKIES SHOULD LINGER THROUGH THE NIGHT. IT WILL BE A CHILLY NIGHT WITH MOST LOCATIONS FALLING BELOW FREEZING. LONG TERM...A CHILLY AND UNSETTLED AIRMASS IS STILL INDICATED OVER NORTHERN COLORADO AND WYOMING ON TUESDAY BENEATH A WESTERN EXTENSION OF THE MAIN UPPER TROUGH CENTERED EITHER OVER EASTERN SOUTH DAKOTA OR WESTERN MINNESOTA TUESDAY MORNING. MODELS ALSO INDICATE A 1030MB SFC HIGH IN THE COLDEST AIR COVERING NORTHERN WYOMING AND NORTH- NORTHWESTERLY SFC-700 MB FLOW OVER NORTH CENTRAL/NORTHEAST COLORADO. MODELS SHOW A SECONDARY UPPER LOW FORMING OVER EASTERN UTAH AROUND MIDDAY...AND THEN TRACKING SOUTHEASTWARD OVER SOUTHWESTERN COLORADO TUESDAY NIGHT. HEIGHT FALLS TO OUR SOUTHWEST IN COMBINATION WITH PRESSURE RISES IN ADVANCE OF THE SOUTHWARD TREKING SFC HIGH IS FORECAST TO PRODUCE WEAK TO MODERATE UPSLOPE FLOW OVER NORTHEAST COLORADO TUESDAY AFTERNOON/EVENING. AS A RESULT COULD SEE SCATTERED SNOW SHOWERS ON THE FRONT RANGE MTNS AND FOOTHILLS...AND ISOLATED RAIN AND SNOW SHOWERS ON THE ADJACENT PLAINS. ANY SNOW ACCUMULATION SHOULD BE MINIMAL. OVERNIGHT THIS SECONDARY UPPER LOW AND SFC HIGH MIGRATE SOUTH AND THE UPSLOPE FLOW ENDS...RESULTING IN AN END TO PRECIP AROUND HERE. MAX TEMPERATURES ON TUESDAY LIKELY TO BE THE COOLEST DURING THE UPCOMING WEEK. HIGHS AT LOWER ELEVATIONS NOT EXPECTED TO CLIMB OUT OF THE 40S. FOR REST OF THE WEEK...FLOW ALOFT RETURNS TO A NORTHWESTERLY COMPONENT WITH RIDGING OVER THE LOWER GREAT BASIN AND DESERT SOUTHWEST. THIS RESULTS IN WARMER TEMPERATURES AND DRY CONDITIONS ON WEDNESDAY. BY THURSDAY...THE ECMWF SHOWS A COLD FRONT RACING SOUTH OUT OF WYOMING AHEAD OF A CLIPPER SYSTEM DROPPING OUT OF THE NORTHERN ROCKIES. THE EC SHOWS THIS FRONT MOVING THROUGH NERN COLORADO THURSDAY MORNING. WHILE THE GFS DOESN/T SHOW IT ARRIVING UNTIL MUCH LATER IN THE DAY. THIS ADDS MORE UNCERTAINTY TO THE HIGH TEMPERATURE FCST FOR THAT DAY. THURSDAY NIGHT AND FRIDAY...ECMWF DRIVES THIS SYSTEM STRAIGHT SOUTH ALONG THE LEE SIDE OF THE ROCKIES INTO NORTHEAST COLORADO POTENTIALLY RESULTING IN AMPLE CLOUD COVER...SIGNIFICANTLY COOLER TEMPERATURES AND A GOOD CHANCE OF PRECIP...LIKELY IN THE FORM OF SNOW FOR THE MTNS AND PLAINS. THE CANADIAN GEM INDICATES A NEARLY SIMILAR PATTERN DEVELOPING...BUT NOT AS COLD OR AS WET. WHEREAS THE GFS SHOWS THIS SYSTEM JUST GLANCING THE AREA BRINGING ONLY SLIGHTLY COOLER TEMPERATURES AND ONLY A SLIGHT CHANCE OF PRECIP MAINLY TO THE NORTHEAST PLAINS. SINCE THIS IS STILL A FEW DAYS AWAY...WILL APPLY A BLEND OF THESE MODELS TO THIS FORECAST ISSUANCE. AVIATION...SOUTHERLY WINDS WILL TURN WEST THEN TO NORTHWEST THIS MORNING AHEAD OF AN APPROACHING COLD FRONT. THE FRONT IS EXPECTED TO PUSH THROUGH AROUND 16Z CAUSING WINDS TO TURN NORTHERLY. CLOUDS WILL INCREASE BEHIND THE FRONT AND SCATTERED RAIN SHOWERS WILL BE POSSIBLE. CEILINGS ARE EXPECTED TO BE 4000 TO 8000 FEET THIS AFTERNOON. CLOUDS WILL LOWER TONIGHT WITH CEILING OF 2000 TO 5000 FEET POSSIBLE. THERE WILL BE A CHANCE CEILINGS COULD FALL BELOW 2000 FEET BY 12Z TUESDAY. HYDROLOGY...NO CONCERNS. SCATTERED RAIN AND MOUNTAIN SNOW SHOWERS WILL MOVE ACROSS THE AREA THROUGH THIS EVENING. RAINFALL AMOUNTS WILL BE LESS THAN A QUARTER INCH. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ031- 033. && $$ SHORT TERM...BARJENBRUCH LONG TERM....BAKER AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS WICHITA KS
308 PM CDT MON OCT 14 2013 .SHORT TERM...(THIS EVENING THROUGH THURSDAY) ISSUED AT 304 PM CDT MON OCT 14 2013 THIS EVENING-TNGT: MOST OF THE WRN HALF OF THE FORECAST AREA REMAINS IN THE DRY SLOT AHEAD OF THE MAIN COLD AND LINE OF CONVECTION CURRENTLY WEST OF KHYS. WITH WARM ADVECTION SHOWERS CONTINUING OVER THE FLINT HILLS AND SOUTHEAST KS. BUT EXPECT RENEWED CONVECTION IN CEN KS AS THE FRONTAL BOUNDARY AND CONVECTION OVER NW KS MOVES SLOWLY E-SE AS THE LATE AFTN CONTINUES. LATEST RAP OUTPUT SHOWS SFC BASED INSTABILITY CONTINUES TO BE LACKING...ONLY AROUND 1800 J/KG FOR AREAS JUST ALONG OR AHEAD OF THE MAIN DRY LINE/COLD FRONTAL BOUNDARY WHERE CLOUDS HAVE THINNED OUT. BUT BULK SHEAR LOOKS TO MAKE UP FOR THIS...WITH IMPRESSIVE BULK SHEAR VALUES OF 50-70KTS. SO COULD SEE A LOW TOPPED LINE CONVECTION MOVE INTO CEN KS FOR THE LATE AFTN/EARLY EVENING HOURS. IMPRESSIVE SHEAR WILL PROBABLY MAKE UP FOR LOWER INSTABILITY VALUES FOR AT LEAST A SMALL SEVERE EVENT IN CEN KS WITH STRONG STORMS MORE LIKELY. NOT TOO IMPRESSED WITH THE ISOLATED TORNADO THREAT (GIVEN BY SPC) THIS FAR SOUTH...AS NOT A CLASSIC COLD CORE SETUP...GIVEN VERTICAL STRETCHING WILL BE LIMITED...UNLESS CLOUDS CAN THIN ENOUGH JUST AHEAD OF THE BOUNDARY/DRYLINE TRIPLE POINT EXPECTED ACROSS CEN KS. SO THINK A VERY SMALL WINDOW OF OPPORTUNITY EXISTS FOR ANY KIND OF TORNADO/FUNNEL...PROBABLY NORTH OF THE FORECAST AREA IN NRN KS. MORE OF A LOW TOPPED LINE WITH QUARTER HAIL AND DAMAGING WIND THE MAIN CONCERNS. EXPECT THIS LINE OF CONVECTION TO MAKE PROGRESS SLOWLY EAST- SOUTHEAST ACROSS THE FORECAST DURING THE EVENING HOURS. LATEST HRRR SEEMS TO HAVE A NICE HANDLE ON HOW THIS SYSTEM WILL PLAY OUT...WITH A THIN LINE OF CONVECTION EXPECTED TO PUSH SLOWLY ACROSS THE AREA. ALSO THINK THE WINDOW OF OPPORTUNITY FOR SEVERE STORMS WILL DIMINISH QUICKLY AFTER SUNSET...WITH THE LOSS OF DAYTIME HEATING AND COOLING OF THE BOUNDARY LAYER. SO MAIN SEVERE THREAT WILL PROBABLY BE WEST OF I-135 GIVEN THE TIMING. TUE-THU: EXPECT THE COLD FRONT TO PUSH SOUTH AND EAST OF THE AREA EARLY ON TUE...WITH SOME LINGERING SHOWERS POSSIBLE ACROSS SOUTHEAST KANSAS. THE MAIN CONCERN FOR TUE-THU WILL BE THE COOLER THAN NORMAL TEMPS AS A CANADIAN RIDGE OF HIGH PRESSURE DROPS SOUTH OUT OF WRN CANADA INTO THE PLAINS. THIS COULD POSSIBLY LEAD TO SOME PATCHY FROST ESPECIALLY OVER CEN KS FOR WED MORNING...AS THE RIDGE AXIS WILL BE OVER THE AREA. WILL SEE ANOTHER MID LEVEL SHORTWAVE MOVE OUT OF THE ROCKIES INTO THE PLAINS FOR THE DAYTIME HOURS ON WED INTO WED EVE. THIS SHORTWAVE WILL MOVE ACROSS THE AREA AS THE SFC RIDGE REMAINS OVER THE REGION....SO LOW LEVEL MOISTURE WILL BE LIMITED AS IT COMES ACROSS. BOTH THE GFS/ECMWF HINT AT SOME VERY LOW POPS AS IT MOVES ACROSS...BUT GFS FORECAST SOUNDINGS SUGGEST MORE OF A SPRINKLE CHANCE FOR MAINLY SOUTHERN KS GIVEN THE DRY LOW LAYERS. KETCHAM .LONG TERM...(FRIDAY THROUGH MONDAY) ISSUED AT 304 PM CDT MON OCT 14 2013 MEDIUM RANGE MODELS SHOW THE NEXT FRONTAL BOUNDARY EXPECTED TO DROP SOUTH ACROSS KS FOR LATE THU NIGHT INTO EARLY ON FRI. BOTH THE GFS/ECMWF TRYS TO BRING THE LOW LEVEL MOISTURE BACK TOWARDS KS BY FRI...AHEAD OF THIS FRONT...BUT TIMING OF THE FRONT SUGGESTS THE BETTER MOISTURE WILL STAY CONFINED TO EXTREME SRN KS OR OK. COULD SEE SOME 850-700H MOISTURE RIDE OVER THE TOP OF THE BOUNDARY FOR A POSSIBLE POST FRONTAL SHOWER/STORM CHANCE...ESPECIALLY ACROSS SRN KS. SO FOR CONSENSUS SAKE...WILL KEEP A LOW POP FOR THIS CHANCE. COOLER THAN NORMAL TEMPS LOOK TO CONTINUE FOR WEEKEND AS SERIES OF FRONTAL BOUNDARY CONTINUE TO KEEP THE WARMER TEMPS SHUNTED FURTHER TO THE SOUTH. KETCHAM && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1242 PM CDT MON OCT 14 2013 THE MAIN AVIATION FORECAST CONCERN IS THE OFF AND ON SHOWERS/THUNDERSTORMS THIS AFTERNOON AND LOW MVFR TO IFR CEILINGS. LOW CEILINGS ARE MOVING INTO THE AREA FROM THE WEST THIS AFTERNOON AND HAVE UPDATED TO DROP ALL CEILINGS TO IFR...EITHER IN A PREVAILING GROUP OR IN A TEMPO. EXPECTING IFR TO LOW MVFR TO PERSIST INTO THE EVENING HOURS. SOUTHERLY WINDS WILL CONTINUE TO BE BREEZY AHEAD OF THE FRONTAL PASSAGE THIS EVENING. THE COLD FRONT/DRY LINE IS EXPECTED TO PUSH EASTWARD LATE THIS AFTERNOON INTO THE EARLY EVENING HOURS. EXPECTING A LINE OF CONVECTION TO MOVE THROUGH THE AREA WITH IT AND HAVE TIMED CURRENT TAFS FOLLOWING GUIDANCE FROM THE LATEST HRRR AND NAM. THIS CONVECTIVE LINE IS NOT ANTICIPATED TO LINGER AT ANY ONE PLACE VERY LONG BEFORE IT MOVES ON TO THE SOUTHEAST. WINDS WILL BECOME NORTHWESTERLY AND BREEZY BEHIND THE FRONT. AS THE FRONT MOVES THROUGH CEILINGS ARE EXPECTED TO LIFT TO VFR. BILLINGS WRIGHT && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 47 62 39 61 / 60 10 10 10 HUTCHINSON 45 60 38 61 / 60 10 10 10 NEWTON 46 60 37 59 / 60 10 10 10 ELDORADO 48 62 39 60 / 60 10 10 10 WINFIELD-KWLD 49 64 41 61 / 60 10 10 10 RUSSELL 40 58 34 58 / 70 0 0 10 GREAT BEND 40 59 33 59 / 70 0 0 10 SALINA 44 60 36 61 / 70 10 10 10 MCPHERSON 45 60 36 60 / 70 10 10 10 COFFEYVILLE 52 64 43 60 / 80 20 10 20 CHANUTE 51 63 42 60 / 70 10 10 10 IOLA 50 63 42 59 / 70 10 10 10 PARSONS-KPPF 52 64 42 60 / 80 20 10 10 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1242 PM CDT MON OCT 14 2013 .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 226 AM CDT MON OCT 14 2013 CURRENT SATELLITE WATER VAPOR IMAGERY SHOWS A HEALTHY UPPER LEVEL WAVE CENTERED NEAR THE FOUR CORNERS REGION WITH A EASTWARD MOVEMENT ACROSS THE ROCKIES. WE SHOULD SEE A ROUND OF SCATTERED TO NUMEROUS ELEVATED SHOWERS/STORMS DEVELOP AHEAD OF THIS WAVE DURING THE MORNING/AFTERNOON HOURS. MEANWHILE...RICHER LOW LEVEL MOISTURE NOW OVER CENTRAL OKLAHOMA WILL CONTINUE TO STREAM NORTHWARD IN ADVANCE OF THE APPROACHING COLD FRONT ACROSS WESTERN AND CENTRAL KANSAS TODAY. STRONG CONVERGENCE AND UPPER DYNAMICS IN CONJUNCTION WITH THIS COLD FRONT WILL INITIATE ANOTHER ROUND OF THUNDERSTORMS OVER WESTERN KANSAS THIS AFTERNOON. THIS ACTIVITY WILL SPREAD EASTWARD INTO CENTRAL KANSAS BY LATE AFTERNOON AND EVENING. A FEW STRONG TO SEVERE LOW-TOPPED THUNDERSTORMS ARE POSSIBLE GIVEN VERY STRONG SHEAR ALOFT AND DAYTIME HEATING BOOSTING THE INSTABILITY...MAINLY FOR LOCATIONS WEST OF I-135. THE STORMS WILL WEAKEN SHORTLY AFTER SUNSET WITH THE LOSS OF DAYTIME HEATING AND COOLING OF THE BOUNDARY LAYER. OTHERWISE BELOW NORMAL TEMPERATURES WILL PREVAIL FOR TUE/WED AS SURFACE HIGH PRESSURE AND ASSOCIATED COOL AIRMASS SETTLES OVER KANSAS. ANOTHER UPPER LEVEL WAVE WILL MOVE ACROSS THE AREA ON WEDNESDAY BUT DRY LOW LEVELS SHOULD KEEP MOST AREAS DRY...PERHAPS A FEW SPRINKLES OR LIGHT RAIN SHOWERS FOR SOUTHERN KANSAS. .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 226 AM CDT MON OCT 14 2013 DEEP UPPER TROUGHING WITH NORTHWEST FLOW WILL PREVAIL OVER THE CENTRAL PLAINS THIS PERIOD WHICH SHOULD RESULT IN COOLER TEMPERATURES. RAIN CHANCES WILL BE LIMITED WITH THIS WEATHER PATTERN SO WILL ONLY CARRY SOME SMALL PRECIPITATION CHANCES FOR THE FRIDAY/FRIDAY NIGHT PERIOD ACROSS SOUTHERN KANSAS. JAKUB && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1242 PM CDT MON OCT 14 2013 THE MAIN AVIATION FORECAST CONCERN IS THE OFF AND ON SHOWERS/THUNDERSTORMS THIS AFTERNOON AND LOW MVFR TO IFR CEILINGS. LOW CEILINGS ARE MOVING INTO THE AREA FROM THE WEST THIS AFTERNOON AND HAVE UPDATED TO DROP ALL CEILINGS TO IFR...EITHER IN A PREVAILING GROUP OR IN A TEMPO. EXPECTING IFR TO LOW MVFR TO PERSIST INTO THE EVENING HOURS. SOUTHERLY WINDS WILL CONTINUE TO BE BREEZY AHEAD OF THE FRONTAL PASSAGE THIS EVENING. THE COLD FRONT/DRY LINE IS EXPECTED TO PUSH EASTWARD LATE THIS AFTERNOON INTO THE EARLY EVENING HOURS. EXPECTING A LINE OF CONVECTION TO MOVE THROUGH THE AREA WITH IT AND HAVE TIMED CURRENT TAFS FOLLOWING GUIDANCE FROM THE LATEST HRRR AND NAM. THIS CONVECTIVE LINE IS NOT ANTICIPATED TO LINGER AT ANY ONE PLACE VERY LONG BEFORE IT MOVES ON TO THE SOUTHEAST. WINDS WILL BECOME NORTHWESTERLY AND BREEZY BEHIND THE FRONT. AS THE FRONT MOVES THROUGH CEILINGS ARE EXPECTED TO LIFT TO VFR. BILLINGS WRIGHT && .PRELIMINARY POINT TEMPS/POPS... WICHITA-KICT 68 47 63 40 / 80 60 10 10 HUTCHINSON 68 45 61 39 / 90 60 10 10 NEWTON 66 46 62 39 / 80 60 10 10 ELDORADO 66 48 63 40 / 80 60 10 10 WINFIELD-KWLD 68 49 65 41 / 100 60 10 10 RUSSELL 70 40 58 35 / 100 70 0 0 GREAT BEND 69 40 59 37 / 100 70 0 0 SALINA 68 44 60 38 / 90 70 10 10 MCPHERSON 67 45 60 39 / 100 70 10 10 COFFEYVILLE 69 52 65 44 / 100 70 20 10 CHANUTE 68 51 64 42 / 100 70 10 10 IOLA 68 50 63 42 / 100 70 10 10 PARSONS-KPPF 68 52 64 43 / 100 70 20 10 && .ICT WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1238 PM CDT Mon Oct 14 2013 ...Update to short term and aviation forecasts... .UPDATE... Issued at 1202 PM CDT MON OCT 14 2013 Weak elevated instability is in place across much of the area early this afternoon with substantial forcing for ascent providing several areas of showers and thunderstorms across Kansas. This will lead to periods of rain and thunder this afternoon and evening with the entire area likely to see rain at some point as well as dry periods. Morning model guidance and observations remain consistent in the development of an area of surface based instability 500 to 1500 J/kg developing in western and central KS this afternoon immediately in advance of the incoming cold front/dryline. This instability will rapidly decrease between 00Z and 03Z, with less than 200 J/kg in advance of the front after 03Z. Deep layer wind shear is strong, and low level shear is rather impressive as well, but not sure if the minimal instability in the local area will allow the wind shear to be fully utilized. It seems that 2 or more lines of convection may steadily move through the narrow warm sector west of the area this afternoon, but will likely congeal into a single line as it approaches the forecast area and the cold front becomes the primary focus for forcing. Currently expect this main line of storms to enter the NW corner of the forecast area around 7 PM, into Manhattan area by 10 PM, and into the Topeka area around midnight before moving out of the area by 4 AM. As previously mentioned, the instability decreases to near zero after 10 PM, and thus expect severe weather to be limited to areas west of Manhattan, although there are occasionally situations in high shear environments during which the lift along a front is sufficient to support a low end severe threat even after instability dissipates. Stronger downdrafts and bowing segments with damaging wind would seem to be the primary severe weather hazard, especially given the strong winds through the lower atmosphere associated with this storms system. There also seems to be a small potential for tornadoes, mainly near and west of Highway 81 where the instability may actually support updraft rotation at times. The overall severe threat in the forecast area is low...but non-zero. && .SHORT TERM...(Today and Tonight) Issued at 403 AM CDT MON OCT 14 2013 Confidence on the specifics of when and where best coverage of precipitation will be over the next 24 hours is not high, but the overall setup is for a widespread wet event over much of the Central Plains. 00Z upper jet structure showed southern branch from central Baja into Kansas with northern branch south and east around the Great Basin upper low then northeast into the Four Corners, and this will push east through tonight with persistent diffluence over Kansas resulting. Deep moisture will steadily increase with stronger mid level flow initially leading to better isentropic lift there (ongoing in central portions of the state) and then somewhat lower as the day progresses and 850 mb winds increase to near 60 kt around 00Z. Elevated creeps up as well for an increasing thunder concern pushing east with time. Have generally indicated the most likely wet periods from mid morning through early evening from west to east, close to the WRF-ARW and recent HRRR runs which seem to be handling the overnight convection the best. They are also similar with surface-based storms breaking out in the KHLC vicinity in the late afternoon hours as the mid level dry slot works northeast and cold front surges east. With plenty of shear, CAPE will be the main limiting factor with this activity maintaining itself through north central Kansas, but at least minor concern for severe hail and wind potential exist in western areas. Cold front sweeps through overnight with clearing and drying taking over. High temperature details are also difficult with onset and duration of daytime precip and continued late-day south winds coinciding with some potential dry periods in the west possibly leading to max values around 0Z. .LONG TERM...(Tuesday through Sunday) Issued at 403 AM CDT MON OCT 14 2013 Drier air will move into eastern Kansas in the wake of the frontal boundary and upper level system on Tuesday. Surface high pressure will build into eastern Kansas Tuesday night and Wednesday keeping winds rather light and temperatures below normal. GFS and ECMWF move an upper trough across the plains Wednesday and Wednesday night. Forecast soundings show dry air in the low and mid levels will be present keeping chances of any measurable precipitation to the south of the CWA. Cannot rule out a few sprinkles south of I-35 though. Models continue to offer differing solutions for Friday through the weekend. The ECMWF has been inconsistent while the GFS has been more consistent on a run to run basis. The ECMWF is much sharper and further south with the mid level trough while the GFS maintains a ridge in the eastern Pacific and northwest flow across the Plains with a broad upper low over Ontario into the Ohio Valley through the weekend. However the ECMWF brings another shortwave trough across Kansas Saturday. Given the differences in the models and limited moisture availability, will go with a dry forecast at this time and will wait and see what later model runs provide. Highs will mainly be in the 60s with lows in the 30s and 40s. && .AVIATION...(For the 18Z TAFs through 18Z Tuesday Afternoon) Issued at 1202 PM CDT MON OCT 14 2013 Periods of showers and embedded thunderstorms will impact TAF sites through this afternoon. Should see predominant MVFR conditions through 00Z, but with a few breaks to VFR possible. MVFR will likely lower to IFR around 01Z at MHK although with some potential to occur sooner. Cigs should stay above 1000 feet at TOP/FOE. A cold front will likely arrive at MHK near 03Z and TOP/FOE near 05Z with a period of IFR conditions and TS. A brief period of strong TS winds will be possible as well. Colder drier air brings VFR and northwest winds after the frontal passage. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Barjenbruch SHORT TERM...65 LONG TERM...53 AVIATION...Barjenbruch
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
129 PM EDT MON OCT 14 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 527 AM EDT MON OCT 14 2013 WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A WELL-DEFINED MID LEVEL LOW LIFTING NE ACROSS HUDSON BAY WITH A TROF EXTENDING SW INTO THE ROCKIES WHERE ANOTHER SHORTWAVE WAS LOCATED OVER UT/CO. THIS SHORTWAVE WILL BEGIN TO AFFECT THE UPPER GREAT LAKES LATER TODAY AND TONIGHT AS IT LIFTS NE. BTWN THE SYSTEMS OVER HUDSON BAY AND THE ROCKIES...SHORTWAVE RIDGING IS SUPPORTING SFC HIGH PRES OVER THE WRN GREAT LAKES EARLY THIS MORNING. EXCELLENT RADIATIONAL COOLING CONDITIONS DURING THE NIGHT HAVE ALLOWED TEMPS TO FALL INTO THE MID 20S TO LWR 30S ACROSS MUCH OF THE INTERIOR OF UPPER MI. HERE AT NWS MQT...THE TEMP SO FAR AS OF 09Z HAS FALLEN TO 30F...MAKING THIS THE FIRST NIGHT THIS AUTUMN WITH A MIN TEMP AT OR BLO FREEZING. THIS TIES 1997 FOR THE LATEST OCCURRENCE OF THE FIRST MIN TEMP AT OR BLO FREEZING IN AUTUMN. SFC HIGH PRES OVER THE AREA WILL SLOWLY MOVE E TODAY WHILE SHORTWAVE OVER THE ROCKIES LIFTS NE INTO THE WRN PLAINS. FORCING ASSOCIATED WITH WAVE WILL REMAIN WELL W AND SW OF HERE TODAY. HOWEVER...RIGHT ENTRANCE OF STRENGTHENING UPPER JET ACROSS NRN ONTARIO/SRN MANITOBA WILL BRING INCREASING UPPER DIVERGENCE OVER THE UPPER MISSISSIPPI VALLEY. UPPER DIVERGENCE ASSOCIATED WITH THE JET IS ALREADY AIDING SOME BANDS OF -SHRA ACROSS ND INTO NW MN EARLY THIS MORNING PER RADAR IMAGERY THOUGH NOT ALL OF IT IS REACHING THE GROUND. THRU LATE AFTN...PLACEMENT OF THE UPPER JET OVER NRN ONTARIO/SRN MANITOBA WILL LEAD TO BEST UPPER DIVERGENCE REMAINING W OF THE FCST AREA AS DOES ISENTROPIC ASCENT AT THE LOWER LEVELS. IN ADDITION...DRY AIR MASS OVER THE AREA (SIMILAR TO 00Z KINL SOUNDING) WILL TAKE SOME TIME TO SATURATE...ESPECIALLY SINCE MAIN MOISTURE TRANSPORT REMAINS TO THE W OVER MN. THUS...PLAN TO MAINTAIN DRY WEATHER ACROSS UPPER MI TODAY...BUT WILL BRING CHC POPS INTO WRN LAKE SUPERIOR MID/LATE AFTN AS ERN FRINGE OF PCPN AREA MAY MAKE SOME PROGRESS INTO DRIER AIR. OTHERWISE...EXPECT A SLOW/STEADY INCREASE IN HIGH/MID CLOUDS THRU THE DAY FROM W TO E AS CLOUDS SPREAD DOWNWIND FROM THE UPPER DIVERGENCE/ISENTROPIC ASCENT AREA TO THE W. GUIDANCE IS WELL CLUSTERED ON MAX TEMPS TODAY...GENERALLY MID/UPPER 50S. AS UPPER JET TO THE N LIFTS SLIGHTLY N AND E...THERE SHOULD BE AN AREA OF -SHRA THAT SHIFTS ACROSS WRN AND NRN LAKE SUPERIOR TONIGHT...PROBABLY TO THE N OF UPPER MI. MEANWHILE...SHORTWAVE OVER THE WRN PLAINS WILL LIFT TO SE SD/SW MN/NW IA BY 12Z TUE WITH HEALTHY FORCING NOTED BY DEEP LAYER QVECTORS SPREADING TOWARD UPPER MI LATE. COMBINED WITH STRONG MOISTURE TRANSPORT AND STRONG ISENTROPIC ASCENT NOTED ON THE 300K SFC...EXPECT SHRA TO ADVANCE NE INTO WRN UPPER MI OVERNIGHT. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 426 AM EDT MON OCT 14 2013 MODELS ARE IN DECENT GENERAL AGREEMENT THROUGH THE EXTENDED...BUT LACK AGREEMENT ON SPECIFIC DETAILS /ESPECIALLY FOR TUE-WED/ THAT LEADS TO A MORE UNCERTAIN FORECAST. A NEARLY STACKED LOW PRESSURE SYSTEM WILL BE OVER FAR SW MN AT 12Z TUE...WITH WAA DRIVEN PRECIP OVER THE W AND CENTRAL CWA THROUGH TUE MORNING. AS THE SYSTEM MOVES OVER OR S OF THE CWA /DEPENDING OF MODEL SOLUTION/ THE TRACK OF THE LOW WILL BECOME MORE IMPORTANT AS A TROWAL WILL ACCOMPANY THE LOW. MODELS HAVE SLOWED THE SYSTEM DOWN A BIT FROM 24 HOURS AGO...AND THERE IS STILL DISAGREEMENT ON THE TIMING OF THE SYSTEM. THE 00Z/14 GFS AND 00Z/14 NAM ARE FASTER AND FARTHER N WITH THE TIMING/TRACK...WHICH MOVES THE TROWAL AND ASSOCIATED RAIN E FASTER ON WED. THE 12Z/13 GEM AND 12Z/13 ECMWF ARE SLOWER...BUT STILL DISAGREE ON THE EXACT TRACK. IF THE MORE SOUTHERN SOLUTION OF THE ECMWF VERIFIES...EVEN THOUGH IT IS SLOWER...RAIN WILL NOT LAST AS LONG ON WED AS EVEN THE GFS/NAM ARE SAYING SINCE THE TROWAL WOULD BE S/SE OF THE CWA WED AFTERNOON. THE SLOWER AND FARTHER N SOLUTION OF THE GEM WOULD RESULT IN THE LONGEST LASTING RAIN AS THE TROWAL STAYS OVER THE CWA INTO EARLY WED NIGHT. WILL CONTINUE TO LEAN TOWARD THE SLOWER SOLUTION GIVEN MODEL TRENDS IN THAT DIRECTION. WILL ALSO KEEP POPS HIGH TUE AND TUE NIGHT AS CONFIDENCE OFF AREA WIDE RAIN IS GOOD AT THAT TIME. FOR WED NIGHT INTO EARLY THU...MODELS GIVE A BRIEF REPRIEVE FROM TROUGHING AS A WEAK RIDGE MOVES OVERHEAD. AFTER THAT...A DEEP UPPER LOW WILL MOVE S FROM HUDSON BAY CLOSER TO THE INTERNATIONAL BORDER IN ONTARIO THROUGH SUN. THIS WILL BRING AN INCREASINGLY COLD AIRMASS OVERHEAD THROUGH AT LEAST THE WEEKEND. LOOKS LIKE A COLD FRONT WILL MOVE THROUGH ON THU...BUT PRECIP IS UNCERTAIN ALONG THE FRONT AS MODELS DISAGREE ON HOW MUCH SYNOPTIC FORCING WILL BE AVAILABLE FROM THE UPPER TROUGH MOVING INTO THE REGION. WILL NOT GO HIGHER THAN SLIGHT CHANCE POPS FOR THU. BY 00Z SAT...850MB TEMPS COOL TO AROUND -2C...SO EXPECT LAKE ENHANCED PRECIP ALONG A SECONDARY AND STRONGER COLD FRONT ON FRI GIVEN LAKE SFC TEMPS OF 9C TO 13C. MODELS THEN SHOW 850MB TEMPS DECREASING TO -5C TO -7C FRI NIGHT THROUGH SUN AS MULTIPLE ROUNDS OF UPPER LEVEL ENERGY MOVE THROUGH. WITH THESE COLDER TEMPS...EXPECT PURE LAKE EFFECT PRECIP WITH INCREASES IN INTENSITY WITH ENHANCEMENT FROM ANY CONTRIBUTING SYNOPTIC ENERGY. AS FOR PRECIP TYPE...SHOULD BE ABLE TO SEE ALL SNOW AT NIGHT/MORNING WHEN TEMPS ARE COOLEST FRI NIGHT THROUGH SUN MORNING...AND MAINLY OVER THE HIGHER TERRAIN. OTHERWISE...HIGH TEMPS WILL BE IN THE 40S SO SNOW IS NOT EXPECTED DURING THE WARMER DAYTIME HOURS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 128 PM EDT MON OCT 14 2013 VFR CONDITIONS ARE EXPECTED FOR ALL THREE SITES OVER THE NEXT 12-18HRS...AS A AREA OF HIGH PRESSURE DEPARTS THE AREA. BUT A LOW PRESSURE SYSTEM MOVING OUT OF THE CENTRAL PLAINS AND INTO WISCONSIN TOMORROW WILL PUSH A LARGE AREA OF RAIN NORTHEAST ACROSS UPPER MICHIGAN LATE TONIGHT THROUGH TUESDAY. THUS...EXPECT THE VFR CEILINGS TO QUICKLY FALL TO MVFR AS THE RAIN INCREASES IN INTENSITY. DUE TO THE UNFAVORABLE SOUTHEASTERLY WINDS...OPTED TO LEAVE KIWD AT MVFR CEILINGS BUT LOWERED KSAW TO IFR CEILINGS TOWARDS MID DAY SINCE THAT IS A FAVORABLE DIRECTION FOR THEM. THIS HEAVIEST BAND OF SHOWERS SHOULD LIFT NORTHEAST DURING THE AFTERNOON...BUT STILL THINK SCATTERED SHOWERS AND LOWER CEILINGS WILL LINGER THROUGH TUESDAY NIGHT. && .MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT 527 AM EDT MON OCT 14 2013 HIGH PRES OVER THE WRN LAKES WILL RESULT IN LIGHT WINDS ACROSS LAKE SUPERIOR...MOSTLY UNDER 15KT THRU MID AFTN. LATER TODAY AND TONIGHT...EASTERLY WINDS WILL BEGIN TO INCREASE FROM W TO E AS THE HIGH SHIFTS E AND LOW PRES LIFTS NE THRU THE PLAINS. BY TUE AFTN...E TO NE WINDS WILL BE INTO THE 20-30KT RANGE OVER WRN LAKE SUPERIOR. AS THE LOW MOVES ENE JUST TO THE S OF LAKE SUPERIOR TUE AFTN THRU WED MORNING...THESE STRONGER WINDS GENERALLY IN THE 20-30KT RANGE WILL SPREAD W TO E ACROSS THE REST OF LAKE SUPERIOR WHILE THE WINDS BACK NORTHERLY. IT`S NOT OUT OF THE QUESTION THAT THERE COULD BE A PERIOD OF GALES TUE NIGHT/WED MORNING ON THE BACKSIDE OF THE LOW. WINDS WILL THEN DIMINISH W TO E WED AFTN/NIGHT AS THE LOW MOVES FARTHER E AND A WEAK SFC HIGH PRES RIDGE ARRIVES. AT THIS TIME...IT APPEARS WINDS WILL MOSTLY BE AOB 20KT THU/FRI. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN... NONE. LAKE SUPERIOR... NONE. LAKE MICHIGAN... NONE. && $$ SHORT TERM...ROLFSON LONG TERM...TITUS AVIATION...SRF MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
401 PM CDT MON OCT 14 2013 .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 157 PM CDT MON OCT 14 2013 THE MASSIVE AREA OF RAIN SHOWERS OVER EASTERN SOUTH DAKOTA AND FAR SOUTHWESTERN MINNESOTA WILL BEGIN TO MAKE ITS EASTWARD SHIFT INTO MINNESOTA THIS EVENING...WITH CLOUDS AND VISIBILITIES LOWERING THROUGHOUT THE EVENING HOURS. PRECIP PROBABILITIES PEAK TO 90-100 PERCENT BETWEEN 03Z AND 09Z TUESDAY...WITH SLIGHTLY LOWER PROBABILITIES ON TUESDAY MORNING AND EARLY AFTERNOON AS THE DRY SLOT WORKS INTO THE AREA WITH THE SURFACE LOW MOVING ACROSS SOUTHERN MINNESOTA. TEMPERATURES WILL HOLD IN THE 40S TONIGHT...WITH NEARLY STEADY OR ONLY SLIGHTLY RISING READINGS ON TUESDAY MORNING. AS THE LOW PASSES BY MID DAY TUESDAY...WILL LIKELY SEE TEMPERATURES GRADUALLY FALL DURING THE AFTERNOON HOURS AS COOLER AIR INFILTRATES THE REGION. THE PASSING OF THE AREA OF LOW PRESSURE WILL ALSO BE MARKED BY BREEZY WINDS EASTERLY WINDS SHIFTING TO NORTHERLY BY TUESDAY EVENING. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 157 PM CDT MON OCT 14 2013 THE PATTERN REMAINS ACTIVE THROUGH THE WEEKEND WITH THE POTENTIAL FOR A FEW ROUNDS OF LIGHT RAIN OR POSSIBLY EVEN SOME SNOW SHOWERS IN CENTRAL MN OR NORTHWEST WI BY THE TIME WE GET TO THE WEEKEND. THE UPPER LOW RESPONSIBLE FOR THE WIDESPREAD RAIN OVER THE NEXT 36 HOURS WILL CLEAR THE FORECAST AREA EARLY WEDNESDAY MORNING. WHILE SOME RESIDUAL BL MOISTURE REMAINS...THE SOUNDINGS DRY OUT NICELY ABOVE 900 MB WITH Q-VECTOR DIVERGENCE AND SUBSIDENCE OVERHEAD BETWEEN 12-15 Z WEDNESDAY. WE MOVED THE RAIN OUT A LITTLE FASTER THAN THE PREVIOUS FORECAST FOR TUESDAY NIGHT...BUT THE CHANGE WAS VERY MINOR. NOT CURRENTLY IN THE FORECAST GIVEN THE UNCERTAINTY IN CLOUD COVER AND HOW QUICK OR IF WE DECOUPLE WEDNESDAY NIGHT...BUT FOG IS CERTAINLY A POSSIBILITY. EVEN THOUGH THE SURFACE HIGH REMAINS CENTERED OVER THE PLAINS...WE GET THE FEELING WINDS WILL GO NEAR CALM WEDNESDAY NIGHT AND THURSDAY MORNING. OTHERWISE...THERE IS GOOD MODEL AGREEMENT IN THE MASS AND MOMENTUM FIELDS THROUGH THE FIRST PART OF THE EXTENDED FORECAST /THURSDAY- SATURDAY/ AND EVEN WHEN LOOKING AT THE MODEL TEMPERATURE SPREADS THERE IS NOT A GREAT DEAL OF VARIABILITY. THERE ARE A COUPLE WEAK FRONT COMING THROUGH ON THURSDAY AFTERNOON/EVENING AND AGAIN FRIDAY NIGHT...BOTH OF WHICH COULD LEAD TO LIGHT SCATTERED SHOWERS AND A FEW HUNDREDTHS OF QPF. THE FRIDAY NIGHT FRONT IS COLD ENOUGH BASED ON THE PROFILES AND BL WETBULB TO THINK ABOUT A RAIN/SNOW MIX. EVEN IF SNOW OCCURS ACROSS THE FAR NORTHERN CWA...IT WILL MELT ON CONTACT GIVEN THE EXPECTED SURFACE TEMPS. ALTHOUGH THERE IS MORE MODEL AMBIGUITY FOR THE SECOND HALF OF THE WEEKEND...CONTINUED COOL /BELOW NORMAL/ TEMPS AND LIGHT RAIN OR RAIN/SNOW MIX ARE LIKELY. LITTLE TO NO RAIN/SNOW ACCUMULATION IS EXPECTED. HOWEVER...WE SHOULD REEMPHASIZE THAT AFTER TOMORROW...THE PRECIP WILL BE VERY LIGHT THROUGH THE && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 126 PM CDT MON OCT 14 2013 PRIMARY CONCERNS ARE TIMING THE ONSET OF MODERATE RAIN AND MVFR/IFR CIGS/VSBYS. THE HRRR HASN/T BEEN TOO SHABBY TODAY MODELING PRECIPITATION TRENDS...AND EXPANDS LIGHT SHOWERS TO EAST CENTRAL MN BY LATE AFTERNOON. MORE WIDESPREAD ACTIVITY DEVELOPS OVER MN SITES AFTER 00Z...AND WI SITES BETWEEN 03Z AND 06Z. STILL LIKE THE 0.5KM NAM12 CONDENSATIONAL PRESSURE DEFICITS FOR TIMING OF CIG REDUCTIONS...WHICH WOULD EXPAND LOW-END MVFR CIGS FROM WEST TO EAST ACROSS MN SITES BETWEEN 01Z AND 05Z...WITH FURTHER REDUCTION TO IFR CIGS AT MN SITES BETWEEN 05Z AND 07Z. WI SITES WOULD SEE SIMILAR REDUCTIONS OCCUR BETWEEN 06Z AND 12Z. EXPECT RAIN TO LINGER ON TUESDAY...ALTHOUGH SOME DRY SLOTTING MAY YIELD PRECIP BREAKS FROM SOUTH/EAST CENTRAL MN INTO WEST CENTRAL WI DURING THE LATE MORNING AND EARLY AFTERNOON UNTIL THE DEFORMATION BAND OF PRECIP SWINGS ACROSS. ANY CIG IMPROVEMENTS TO MVFR WOULD BE BRIEF...WITH PREDOMINANT IFR CIGS EXPECTED ONCE THEY DEGRADE TONIGHT. EAST/SOUTHEAST WINDS BEGIN TO SHIFT TO THE WEST/NORTHWEST WITH THE FROPA ON TUESDAY AFTERNOON. KMSP... EXPECT THE BAND OF LIGHT RAIN SHOWERS /VFR CAT/ OVER SOUTHWEST MN TO REACH KMSP AROUND 22Z...WITH MORE MODERATE SHOWERS AND MVFR CIGS DEVELOPING BY 03Z...WHEN CIGS/VSBYS WILL ALSO START REDUCING. ANTICIPATE CIGS TO REDUCE TO AROUND 1500 FT BY 06Z...AND THEN LOWER INTO THE IFR CATEGORY BY 09Z. COULD SEE SOME BREAKS IN THE RAIN ON TUESDAY MORNING AND EARLY AFTERNOON WHEN SOME DRIER AIR WORKS IN...BUT CIGS SHOULD BE PRIMARILY IFR THROUGH THE PERIOD ONCE THEY LOWER TONIGHT. /OUTLOOK FOR KMSP/ WED...IFR/MVFR. CHANCE -RA EARLY. WINDS NW 5-10 KTS. THU...VFR. WINDS NW 10 KTS. FRI...VFR. WINDS NW 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...LS LONG TERM...CLF AVIATION...LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
125 PM CDT MON OCT 14 2013 .UPDATE... FOR 18Z AVIATION DISCUSSION BELOW && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 352 AM CDT MON OCT 14 2013 HIGH PRESSURE... WHICH BROUGHT US THE BEAUTIFUL DAY ON SUNDAY WAS CENTERED OVER WISCONSIN EARLY THIS MORNING... WHILE A DEVELOPING LOW PRESSURE SYSTEM WAS LOCATED OVER NORTHEAST COLORADO. MODEL TRENDS REMAIN CONSISTENT ON DEEPENING THE LOW PRESSURE SYSTEM AS IT MOVES TO FAR SOUTHERN MINNESOTA BY MIDDAY TUESDAY AND THEN OFF TO WISCONSIN TUESDAY NIGHT. LOW LEVEL MOISTURE TRANSPORT IS ON THE INCREASE THIS MORNING ACROSS EASTERN NEBRASKA AND EASTERN SOUTH DAKOTA... WITH SHOWERS INCREASING IN COVERAGE AND INTENSITY. THE MOISTURE TRANSPORT REMAINS NEARLY STATIONARY TODAY ALONG THE I-29 CORRIDOR... WHICH KEEPS THE MAIN PRECIPITATION SHIELD THAT IS DEVELOPING FOCUSED OVER OUR WESTERN MINNESOTA COUNTIES THROUGH MUCH OF THE DAY. UPGLIDE AND SATURATION GRADUALLY SPREAD INTO EASTERN MINNESOTA THIS AFTERNOON WITH RAIN MOVING INTO THE TWIN CITIES BY LATE IN THE DAY AND ACROSS WESTERN WISCONSIN THIS EVENING. THE 00Z SPC-WRF REFLECTIVITY PROGS THROUGH 36 HOURS DEPICT QUITE WELL HOW WE FEEL THIS EVENT WILL UNFOLD. WITH THE MOISTURE TRANSPORT HOLDING BACK TO THE WEST TODAY ALONG WITH THE STRONG FORCING DEVELOPING... RAIN AMOUNTS OF AROUND AN INCH ARE LIKELY TODAY ACROSS WEST CENTRAL MINNESOTA WITH VARIOUS WRF/S...INCLUDING THE HOPWRF... SHOWING THE POTENTIAL FOR 2 TO 3 INCHES ACROSS SOUTHEAST SOUTH DAKOTA AND NORTHEAST NEBRASKA. AS THE LOW ADVANCES NORTHEAST TONIGHT... THE MOISTURE TRANSPORT WILL PROGRESS INTO EASTERN MN AND WESTERN WI AND CURVE BACK INTO WEST CENTRAL MINNESOTA. STRONG MID LEVEL FRONTOGENESIS IS DEPICTED BY ALL MODELS IN THE RESULTING DEFORMATION ZONE THAT DEVELOPS FROM EASTERN SOUTH DAKOTA THROUGH CENTRAL MINNESOTA. HENCE... THE FOCUS ON THE HIGHEST RAINFALL AMOUNTS TONIGHT ARE ACROSS EASTERN SOUTH DAKOTA THROUGH CENTRAL MINNESOTA. COMBINING TODAY AND TONIGHT YIELDS A RAINFALL FORECAST OF 2 TO 2.25 INCHES IN OUR FAR WESTERN COUNTIES WITH 1.25 TO 1.75 INCHES IN CENTRAL MINNESOTA. THIS AREA IS IN A SLIGHT RISK OF EXCESSIVE RAINFALL FROM HPC. WE ARE NOT ANTICIPATING WATER PROBLEMS AT THIS TIME GIVEN THE RECENT DRY CONDITIONS AND HOW THIS RAIN IS SPREAD OUT OVER TIME. RAIN AMOUNTS ARE LIMITED SOMEWHAT ACROSS EAST CENTRAL THROUGH SOUTH CENTRAL MINNESOTA AS A DRY SLOT MOVES IN DURING THE 06Z-12Z TIME FRAME. ANOTHER CONCERN FOR TONIGHT IS THE THREAT OF THUNDER OVER SOUTHERN MINNESOTA. BEST LI FORECASTS FROM THE NAM STILL SUGGEST NEAR ZERO PASSING THROUGH. CAPE IS SMALL (LESS THAN 250 J/KG) ABOVE THE WARM LAYER CENTERED NEAR 750 MB. THE THREAT SEEMS MINIMAL AND IT WAS KEPT OUT OF THE FORECAST. SPC ALSO HAS US OUTSIDE OF THE GENERAL THUNDER CONTOUR. THE TEMPERATURE FORECAST TODAY IS A TOUGH ONE WITH THE CLOUDS AND DEVELOPING PRECIPITATION IN THE WEST ALONG WITH SOME SUNSHINE EARLY ON IN THE EAST. TEMPERATURES IN THE WEST ARE LIKELY TO BE NEARLY STEADY IN THE UPPER 40S TO LOWER 50S WITH A RUN INTO THE LOWER 60S FORECAST FOR SOUTHEAST MINNESOTA AND WEST CENTRAL WISCONSIN. LOWS TONIGHT WILL BE QUITE MILD AHEAD OF THE LOW WITH MIDDLE TO UPPER 40S COMMON. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 352 AM CDT MON OCT 14 2013 THE LONG TERM PERIOD WILL START WITH THE UPPER LOW CURRENTLY DOWN IN THE FOUR CORNERS REGION ENTERING SW MN TUESDAY MORNING. THIS LOW WILL FILL AND MOVE INTO THE GREAT LAKES ON WEDNESDAY AS SHORT WAVE RIDGING MOVES ACROSS THE REGION OUT AHEAD OF A DEEP TROUGH THAT WILL CARVE ITSELF OUT A HOME FROM HUDSON BY BACK SOUTHWEST TO THE BAJA PENINSULA FRIDAY INTO THE WEEKEND. MODEL SPREAD/DISCREPANCIES ARE FAIRLY MINIMAL THROUGH FRIDAY...BUT AGREEMENT ON SMALL SCALE DETAILS BEGINS TO BREAK DOWN FAIRLY QUICKLY BY THE WEEKEND. TUESDAY MORNING WILL BE STARTING OUT WITH A SFC LOW OVER SW MN THAT WILL SLIDE OVER TO NEAR GREEN BAY BY THE END OF THE DAY TUESDAY. AHEAD OF THIS LOW...MODELS CONTINUE TO SHOW A MID LEVEL DRY SLOT WORKING UP TO ABOUT THE TWIN CITIES TUESDAY MORNING THAT THEN SLIDES EAST WITH THE LOW DURING THE DAY. FORECAST SOUNDINGS SHOW THE MOIST LAYER EXTENDING FROM THE SFC UP TO ABOUT 825 MB...WITH IT DRY ABOVE THAT. OMEGA WITHIN THIS MOIST LAYER REMAINS NEGATIVE...WHICH MEANS UPWARD MOTION WILL CONTINUE DESPITE THE LOSS OF DEEP MOISTURE...PERFECT CONDITIONS FOR THE FORMATION OF DRIZZLE. THEREFORE...ADDED A DRIZZLE MENTION TO THE FORECAST TUESDAY MORNING THROUGH THE AFTERNOON BENEATH THE DRY SLOT FROM SOUTH CENTRAL MN INTO WRN WI. NORTH AND WEST OF THE DRY SLOT...AN ACTIVE DEFORMATION REGION IS EXPECTED TO PERSIST THROUGH THE DAY ON TUESDAY...SO EXTENDED CATEGORICAL POPS THROUGH THE DAY ACROSS MOST OF THE MN CWA TO ACCOUNT FOR THE LIGHT DEFORMATION RAINS EXPECTED TO MOVE IN RIGHT BEHIND THE DRY SLOT. PRECIP WILL END FROM WEST TO EAST TUESDAY NIGHT AND ENDED ANY RAIN MENTION IN THE ERN CWA AFTER 15Z WEDNESDAY. FOR WEDNESDAY...MAINLY SUNNY SKIES ARE EXPECTED. THE NEXT FRONT TO PUSH THROUGH THE AREA WILL BE PUSHING INTO NODAK DURING WEDNESDAY AFTERNOON AND A SLIGHT REBOUND IN LOW LEVEL TEMPS/THICKNESSES WILL ALLOW TEMPERATURES TO WARM BACK SIMILAR TO WHAT WAS SEEN SUNDAY...JUST A COUPLE OF DEGREES COOLER. THAT FRONT WILL PUSH ACROSS THE MPX AREA ON THURSDAY. FORECAST SOUNDINGS ARE STILL QUITE DRY IN THE WAKE OF THE EARLY WEEK SYSTEM AND THIS FRONT WILL NOT HAVE MUCH MOISTURE TO WORK WITH...HENCE A MAINLY DRY PASSAGE IS EXPECTED. AT THIS POINT...MODELS SHOW BEST PRECIP CHANCES EXISTING OVER IN WI THU AFTERNOON...WHEN THE GFS SHOWS WEAK...MOIST UPGLIDE ON THE 290K/295K SFCS. COLD ADVECTION WILL SET IN BEHIND THE FRONT...RESULTING IN STEEP LAPSE RATES AND UNSTABLE SOUNDINGS FOR FRIDAY...WHICH LOOKS TO FEATURE BREEZY NW WINDS...PLENTY OF STRATOCU...AND SCATTERED SHOWERS. GIVEN FREEZING LEVELS DOWN UNDER H85 /AROUND 3K FT AGL/...WOULD NOT BE AT ALL SURPRISED TO SEE SLEET MIX IN WITH ANY ACTIVITY THAT DOES DEVELOP IN THE AFTERNOON. FOR THE WEEKEND...SATURDAY MORNING LOOKS TO FEATURE THE FIRST WIDESPREAD FREEZE OF THE FALL. BEYOND THAT THOUGH...THE GFS SHOWS COLD AIR REMAINING IN PLACE THROUGH THE WEEKEND...WHILE THE ECMWF SHOWS TEMPERATURES BEGINNING TO MODIFY SATURDAY OUT AHEAD OF A STRONG CLIPPER SYSTEM IT SWINGS THROUGH ON SUNDAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 126 PM CDT MON OCT 14 2013 PRIMARY CONCERNS ARE TIMING THE ONSET OF MODERATE RAIN AND MVFR/IFR CIGS/VSBYS. THE HRRR HASN/T BEEN TOO SHABBY TODAY MODELING PRECIPITATION TRENDS...AND EXPANDS LIGHT SHOWERS TO EAST CENTRAL MN BY LATE AFTERNOON. MORE WIDESPREAD ACTIVITY DEVELOPS OVER MN SITES AFTER 00Z...AND WI SITES BETWEEN 03Z AND 06Z. STILL LIKE THE 0.5KM NAM12 CONDENSATIONAL PRESSURE DEFICITS FOR TIMING OF CIG REDUCTIONS...WHICH WOULD EXPAND LOW-END MVFR CIGS FROM WEST TO EAST ACROSS MN SITES BETWEEN 01Z AND 05Z...WITH FURTHER REDUCTION TO IFR CIGS AT MN SITES BETWEEN 05Z AND 07Z. WI SITES WOULD SEE SIMILAR REDUCTIONS OCCUR BETWEEN 06Z AND 12Z. EXPECT RAIN TO LINGER ON TUESDAY...ALTHOUGH SOME DRY SLOTTING MAY YIELD PRECIP BREAKS FROM SOUTH/EAST CENTRAL MN INTO WEST CENTRAL WI DURING THE LATE MORNING AND EARLY AFTERNOON UNTIL THE DEFORMATION BAND OF PRECIP SWINGS ACROSS. ANY CIG IMPROVEMENTS TO MVFR WOULD BE BRIEF...WITH PREDOMINANT IFR CIGS EXPECTED ONCE THEY DEGRADE TONIGHT. EAST/SOUTHEAST WINDS BEGIN TO SHIFT TO THE WEST/NORTHWEST WITH THE FROPA ON TUESDAY AFTERNOON. KMSP... EXPECT THE BAND OF LIGHT RAIN SHOWERS /VFR CAT/ OVER SOUTHWEST MN TO REACH KMSP AROUND 22Z...WITH MORE MODERATE SHOWERS AND MVFR CIGS DEVELOPING BY 03Z...WHEN CIGS/VSBYS WILL ALSO START REDUCING. ANTICIPATE CIGS TO REDUCE TO AROUND 1500 FT BY 06Z...AND THEN LOWER INTO THE IFR CATEGORY BY 09Z. COULD SEE SOME BREAKS IN THE RAIN ON TUESDAY MORNING AND EARLY AFTERNOON WHEN SOME DRIER AIR WORKS IN...BUT CIGS SHOULD BE PRIMARILY IFR THROUGH THE PERIOD ONCE THEY LOWER TONIGHT. /OUTLOOK FOR KMSP/ WED...IFR/MVFR. CHANCE -RA EARLY. WINDS NW 5-10 KTS. THU...VFR. WINDS NW 10 KTS. FRI...VFR. WINDS NW 10 KTS. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SHORT TERM...RAH LONG TERM...MPG AVIATION...LS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1223 PM CDT MON OCT 14 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 445 AM CDT MON OCT 14 2013 AN ACTIVE 24 HOURS WITH QUITE HIGH MEASURABLE RAIN CHANCES IS ALREADY UNDERWAY ACROSS THE CWA...WITH PLENTY OF FORECAST CHALLENGES RANGING FROM TRYING TO REFINE SHORT-TERM POPS...ASSESSING THE MAGNITUDE OF A POSSIBLE SEVERE WEATHER RISK THIS AFTERNOON-EARLY EVENING...DETERMINING THE EFFECTS OF WIDESPREAD CLOUD COVER/PRECIP ON HIGH TEMPS...AND ALSO TRYING TO DETERMINE HOW CLOSE ESPECIALLY THE NORTHWESTERN CWA MAY COME TO AT LEAST BRIEFLY FLIRTING WITH WIND ADVISORY CRITERIA TONIGHT IN THE WAKE OF THE PASSING LOW. 08Z OBJECTIVE SURFACE ANALYSIS REVEALS A GRADUALLY-TIGHTENING PRESSURE GRADIENT...BETWEEN A ROUGHLY 1031 MILLIBAR HIGH OVER THE GREAT LAKES...AND A 1006 LOW OVER NORTHEAST CO. AS A RESULT...SUSTAINED SOUTHEAST WINDS ACROSS MOST OF THE CWA AT THIS HOUR ARE AVERAGING AT LEAST 10-15 MPH WITH HIGHER GUSTS TO AROUND 20 MPH...ESPECIALLY IN THE WEST. ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA HIGHLIGHT A VIGOROUS MID/UPPER LEVEL TROUGH PLOWING ACROSS THE ROCKIES...WITH ITS 500MB VORT MAX CURRENTLY SWINGING OVER THE 4-CORNERS AREA. UPPER LEVEL FLOW HAS BECOME INCREASINGLY DIFFLUENT OVER THE CENTRAL PLAINS AHEAD OF A 100+KT JET STREAK APPROACHING FROM SOUTHERN CO...AND FARTHER DOWN A 40-50KT SOUTHERLY LOW LEVEL JET IS EVIDENT AT 850MB...RIGHT OVER THE HEART OF CENTRAL/WESTERN NEB AND KS. MUCH AS EXPECTED FOR DAYS NOW...STOUT LOW-MID LEVEL MOISTURE ADVECTION ESPECIALLY EVIDENT IN THE 850-700MB LAYER HAS RESULTED IN A GRADUAL INCREASE IN SHOWER/THUNDERSTORM ACTIVITY WITHIN THE CWA DURING THE NIGHT. OF COURSE...ITS NOT RAINING EVERYWHERE AT ONCE...AND EARLIER ON MOST OF THE PRECIP WAS FOCUSED IN NORTHWESTERN COUNTIES...BUT OVER THE PAST FEW HOURS THE MAIN FOCUS HAS TRANSITIONED TO ROUGHLY THE EASTERN 1/2 OF THE CWA...WITH MUCH OF THE WEST IN AT LEAST A SHORT TERM LULL. ALTHOUGH ITS QUITE POSSIBLE THAT A FEW OF THE STRONGER STORMS EARLY THIS MORNING HAVE PRODUCED/COULD PRODUCE VERY SMALL HAIL...NOT EXPECTING ANY SEVERE STORMS GIVEN MUCAPE IN THE 850-700MB LAYER ONLY AVERAGING A FEW HUNDRED J/KG PER LATEST RAP- BASED MESOANALYSIS. NOT SURPRISINGLY...TEMPS HAVE BEEN FAIRLY STEADY EARLY THIS MORNING UNDER WHAT HAS BECOME WIDESPREAD LOW CLOUD COVER AND SLOWLY-INCREASING DEWPOINTS...WITH MOST ALL PLACES CURRENTLY SOMEWHERE IN THE 50S. FOCUSING ON THE DAYTIME HOURS TODAY THROUGH 00Z/7PM...TOOK A BEST STAB AT 3-HOURLY POP TRENDS...BUT THE BOTTOM LINE IS THAT THE ENTIRE CWA IS SPORTING AN 80-90 PERCENT CHANCE OF MEASURABLE RAIN THROUGH SUNSET...ITS JUST A MATTER OF WHEN IT FALLS AND HOW MUCH FALLS. IN THE BIG PICTURE...THE PRIMARY 500MB VORT MAX ASSOCIATED WITH THE INCOMING TROUGH IS SCHEDULED TO REACH THE NEB PANHANDLE BY MID-DAY AS IT DEEPENS AND SWINGS NORTHEAST IN A NEGATIVELY TILTED FASHION...AND THEN REACHING FAR NORTH CENTRAL NEB BY AROUND SUNSET. IN SUIT...THE ASSOCIATED SURFACE LOW CURRENTLY CENTERED IN NORTHEAST CO IS PROGGED TO SHIFT NORTHEAST AS WELL...BUT SLIGHTLY SOUTHEAST OF THE MID LEVEL LOW TRACK...MEANING THAT IT GENERALLY SKIRTS JUST ALONG THE FAR WEST-CENTRAL/NORTHWEST EDGES OF THE CWA AS IT TRACKS NORTHEAST INTO NORTH CENTRAL NEB BY SUNSET WITH A CENTRAL PRESSURE AROUND 1003MB. MEANWHILE...A STOUT 50+KT LOW LEVEL JET WILL PERSIST OVER THE CWA PRETTY MUCH ALL DAY...WHICH IN TANDEM WITH CONTINUED LOW-MID LEVEL THETA-E ADVECTION SHOULD PROMOTE RATHER WIDESPREAD SHOWERS AND AT LEAST ISOLATED TO SCATTERED EMBEDDED THUNDERSTORMS THROUGH MUCH OF THE DAY. ITS YET TO BE SEEN WHETHER THIS WIDESPREAD PRECIPITATION MAINLY STAYS FOCUSED ACROSS THE EASTERN HALF OF THE CWA AS CURRENTLY HAPPENING...OR EVENTUALLY ALSO DEVELOPS OVER...OR MOVES INTO WESTERN AREAS AS WELL. MODELS VARY...WITH SOME ENDING THE LULL OVER THE WEST BY MID-MORNING...WHILE OTHERS SUCH AS THE LATEST HRRR CONTINUE TO FOCUS ON EASTERN AREAS AT LEAST THROUGH MID-DAY. AT ANY RATE...WOULD BE QUITE SURPRISED IF ANY OF THE CWA GOT THROUGH THE ENTIRE DAY WITHOUT MEASURABLE RAIN...AS MANY EASTERN AREAS COULD EASILY RECEIVE 0.50-0.75 INCH OR MORE THROUGH SUNSET. TURNING TO THE AFTERNOON HOURS...AS HAS ALSO BEEN ADVERTISED FOR A FEW DAYS NOW WE ARE FACING A CONDITIONAL SEVERE WEATHER THREAT...AS SPC HAS THE MAJORITY OF THE CWA IN A DAY 1 SLIGHT RISK AREA. THE MILLION DOLLAR QUESTION HERE IS...HOW MUCH CLEARING WILL TAKE PLACE JUST WEST OF...AND POSSIBLY INTO THE FAR SOUTHWESTERN PORTIONS OF THE CWA THIS AFTERNOON UNDER THE INVADING MID LEVEL DRY SLOT AND JUST AHEAD OF THE INVADING COLD FRONT/DRYLINE COMBO...TO PROMOTE SUFFICIENT DESTABILIZATION FOR SEVERE STORMS. FOLLOWING THE LEAD OF THE LATEST RAP...THE VAST MAJORITY OF THE CWA WILL REMAIN LOCKED UNDER LOW CLOUDS AND SCATTERED TO WIDESPREAD ELEVATED PRECIP THROUGH NEARLY THE ENTIRE DAY...WITH LIKELY NOTHING MORE THAN A HIT AND MISS THREAT OF SMALL HAIL POSSIBLY UP TO AROUND DIME SIZE. HOWEVER...BY MID-LATE AFTERNOON...THE RAP BRINGS A NARROW NORTH-SOUTH CORRIDOR OF LOW-LEVEL CAPE POTENTIALLY INTO THE 1000-1500 J/KG RANGE INTO MAINLY THE WESTERN 1/4 OF THE CWA. AS A RESULT...AND AS DEPICTED FAIRLY WELL BY THE 00Z RUNS OF THE 4KM WRF-NMM AND ARW AND ALSO THE LATEST HRRR...A LINE OF FAST MOVING STRONG TO POTENTIALLY SEVERE STORMS COULD SWEEP FROM WEST- EAST ACROSS MUCH OF THE CWA MAINLY BETWEEN 4PM-9PM...BUT LIKELY GRADUALLY LOSING STEAM AS IT DOES SO. ALTHOUGH LOW LEVEL SHEAR WILL BE STRONG...THUS MEANING THAT A BRIEF TORNADO THREAT IS NON- ZERO...EXPECT SYNOPTIC FORCING TO BE STRONG ENOUGH TO FORCE A LINEAR MODE FAIRLY QUICKLY...WITH THE MAIN THREAT BEING WINDS GUSTS TO AT LEAST 60 MPH...AND MAYBE SOME MARGINALLY SEVERE HAIL TO AROUND QUARTER SIZE. ALTHOUGH THE SPC SLIGHT RISK AREA COVERS NEARLY THE ENTIRE CWA...WILL BE FOCUSING THE LOCAL HAZARDOUS WEATHER OUTLOOK MAINLY ON THE SOUTHWEST HALF OF THE CWA...OR ROUGHLY SOUTHWEST OF A LOUP CITY-BELOIT LINE WHERE INSTABILITY SHOULD BE MAXIMIZED BEFORE IT DROPS OFF FARTHER EAST AS NIGHT FALLS. TURNING BRIEFLY TO OTHER ELEMENTS TODAY...HIGH TEMPERATURES WILL BE QUITE TRICKY AND OBVIOUSLY VERY DEPENDENT ON HOW MUCH PRECIP IS FALLING AND WHETHER ANY CLEARING TAKES PLACE IN THE SOUTHWEST...BUT BASED ON A VARIED BLEND OF SHORT TERM MODELS/GUIDANCE HAVE A RANGE FROM ONLY MID-UPPER 50S NORTH TO MID- UPPER 60S SOUTHWEST...WHICH IS A BIT COOLER THAN A STRAIGHT MET/MAV GUIDANCE BLEND AND COUNTS ON LOW CLOUDS HOLDING FIRM ACROSS MOST OF THE AREA. WIND-WISE TODAY...ALTHOUGH CERTAINLY QUITE BREEZY WITH SUSTAINED SOUTH-SOUTHEAST SPEEDS AVERAGING 20-25 MPH WITH GUSTS TO AROUND 30 MPH AHEAD OF THE APPROACHING COLD FRONT...NOT EXPECTING SUSTAINED SPEEDS TO BREACH ADVISORY CRITERIA OF 30+ MPH. TURNING TO THE TONIGHT PERIOD/7PM-7AM/...THE MAIN FOCUS IS ON HOW QUICKLY CONVECTION VACATES THE AREA...AND HOW STRONG WEST- NORTHWEST WINDS BECOME. ON THE BIG PICTURE...THERE IS GOOD AGREEMENT THAT THE CENTER OF THE CLOSED MID LEVEL LOW WILL ONLY SLOWLY MIGRATE FROM FAR NORTH CENTRAL NEB TO NEAR SIOUX FALLS...WHILE THE ATTENDANT SURFACE LOW FOLLOWS A SIMILAR PATH AND MAINTAINS A SIMILAR CENTRAL PRESSURE AROUND 1003MB. IN THE STOUT COLD AIR ADVECTION REGIME BEHIND THE DEPARTING LOW...AND IN AN ENHANCED PRESSURE GRADIENT BETWEEN THE SURFACE LOW AND AN EXPANSIVE HIGH NOSING INTO THE REGION FROM THE NORTHERN ROCKIES...ITS QUITE POSSIBLE THAT ESPECIALLY THE NORTHWEST HALF OF THE CWA MAY BE OVERALL-WINDIER TONIGHT THAN THEY ARE DURING THE DAY TODAY...EXCEPT THIS TIME OUT OF THE WEST-NORTHWEST BEHIND THE QUICKLY PASSING COLD FRONT...WHICH IS SLATED TO CRUISE ACROSS THE CWA GENERALLY BETWEEN 5-11PM. ALTHOUGH ITS NOT OUT OF THE QUESTION THAT THE LATEST SUITE OF MODELS/GUIDANCE ARE UNDER-DOING WIND SPEEDS A BIT...AT LEAST FOR NOW EXPECT SUSTAINED SPEEDS TO ONLY AVERAGE IN THE 20-25 MPH RANGE WITH GUSTS OF 30-35 MPH...AND THUS FALLING AT LEAST SLIGHTLY SHORT OF ADVISORY CRITERIA. NEIGHBORING OFFICES TO THE WEST HAVE ISSUED WIND HEADLINES FOR PORTIONS OF TODAY/TONIGHT...BUT AT THIS POINT JUST DON/T SEE THE LOCAL AREA BEING QUITE WINDY ENOUGH TO JUSTIFY AN ADVISORY...ALTHOUGH OF COURSE LATER SHIFTS WILL HAVE TO RE-EVALUATE THIS. OTHERWISE...IN TERMS OF PRECIP TRENDS...HAVE SLIGHTLY SPED UP THE DEPARTURE OF SHOWERS/STORMS...WITH MUCH OF THE WESTERN 1/2 OF THE CWA LIKELY DRIED OUT BY AROUND SUNSET...WHILE LIKELY POPS CONTINUE IN EASTERN COUNTIES THROUGH 02Z/9PM BEFORE QUICKLY DIMINISHING AND ENDING BY MIDNIGHT. ITS POSSIBLE THAT STORMS COULD CARRY AT LEAST A MARGINAL SEVERE THREAT UNTIL THEY DEPART EASTERN AREAS...BUT WOULD EXPECT THE MAIN THREAT TO DIMINISH POST-SUNSET. ALTHOUGH THE MAIN AREA OF PRECIP WILL VACATE THE AREA THIS EVENING...DID INTRODUCE A SLIGHT CHANCE OF LIGHT RAIN TO FAR NORTHERN ZONES THROUGH THE LATE EVENING/OVERNIGHT HOURS TO ACCOUNT FOR PRECIPITATION POSSIBLY BARELY BRUSHING THE CWA ON THE SOUTH-END OF THE WRAP-AROUND SHIELD. THE VAST MAJORITY OF THIS SHOULD FOCUS ACROSS FAR NORTHERN NEB HOWEVER. MADE LITTLE CHANGE TO OVERNIGHT LOWS...WITH MOST OF THE CWA BOTTOMING OUT IN THE 39-42 RANGE BY SUNRISE TUESDAY...ALTHOUGH ESPECIALLY THE NORTHWEST HALF OF THE AREA MAY BE HELD UP A BIT BY PLENTY OF LOW STRATUS WRAPPING BACK SOUTHWARD INTO THE AREA. THOSE VENTURING OUT LATE TONIGHT/EARLY TUESDAY WILL DEFINITELY NOTICE A BITE TO THE AIR...WITH WIND CHILL READINGS WELL DOWN INTO THE 30S. .LONG TERM...(TUESDAY THROUGH SUNDAY) ISSUED AT 445 AM CDT MON OCT 14 2013 PRIMARY CONCERNS WILL BE WINDY CONDITIONS ON TUESDAY AND LOW TEMPERATURES WITH FROST/FREEZE CHANCES ON WEDNESDAY AND THURSDAY MORNING. BUSY PATTERN STARTING OUT TUESDAY MORNING AS 500MB CLOSED LOW IS EXPECTED TO BE NEAR THE SDAK/MN BORDER WITH THE SYSTEM STACKED AS SURFACE LOW SHOULD BE JUST A TAD SOUTHEAST OF THE UPPER LOW POSITION. IN ADDITION TO THE UPPER LOW...TROUGHINESS IS EXPECTED TO EXTEND WESTWARD TOWARD THE CENTRAL ROCKIES. AS NOTED ABOVE...EXPECT WINDY CONDITIONS DURING THE DAYTIME TUESDAY AS WE SIT IN BETWEEN A WOUND UP SURFACE LOW NEAR THE MN/IA BORDER AND A STRONG HIGH PRESSURE BUILDING INTO CENTRAL WYOMING. THIS WILL RESULT IN A 20MB PRESSURE GRADIENT ACROSS NEBRASKA. SHOULD SEE SUSTAINED 25 MPH WINDS AT LEAST AND MAY BE APPROACHING ADVISORY CRITERIA ESPECIALLY IN THE NORTHERN HALF OF THE CWA FROM MID MORNING TO MID AFTERNOON. SOME LIGHT RAIN ALSO POSSIBLE ON TUESDAY IN THE NORTHERN QUARTER OF THE CWA WRAPPING AROUND THE LOW PRESSURE. IF WE DO GET ANY IT SHOULD NOT AMOUNT TO MUCH MORE THAN ONE OR TWO HUNDREDTHS. BY WEDNESDAY MORNING THE SURFACE LOW WILL HAVE MOVED INTO THE GREAT LAKES REGION WITH THE SURFACE HIGH BUILDING INTO OUR AREA. THIS WILL BRING LIGHTER WINDS AND ALSO EXPECTING SKIES TO CLEAR OUT...SO WITH DEWPOINTS IN THE UPPER 20S TO NEAR 30...MUCH OF THE CWA STANDS A DECENT CHANCE OF SEEING FROST WED MORNING. ON THURSDAY ANOTHER MID LEVEL WAVE WILL SLIDE ACROSS DRAGGING A COLD FRONT THROUGH THE CWA. DOESN`T APPEAR TO BE MUCH MOISTURE WITH THIS SYSTEM AND WILL KEEP FORECAST DRY. FRIDAY IS A LITTLE MORE INTERESTING AS A DEEP UPPER LOW SWINGS ACROSS CANADA AND THE NORTHERN PART OF THE U.S. THE EC MODELS BRINGS DOWN MUCH COLDER AIR THAN THE OPERATIONAL GFS. IT ALSO BRINGS A STRONG MID LEVEL WAVE DOWN THE BACKSIDE OF THE LOW ON FRIDAY AND GENERATES SOME MODERATE QPF WITH IT. THE GFS NOT SHOWING THIS AND THE GEM IS ALSO UNDERPLAYING THIS FEATURE. CHECKING THE ALL BLEND POPS...THEY ARE ONLY IN THE 15 TO 20 PERCENT RANGE FOR THE DAYTIME FRIDAY. BACK TO THE EC...IF ONE WERE TO ONLY LOOK AT 1000-500 MB THICKNESSES...THERE MAY BE CAUSE FOR CONCERN AS THE EC IS SHOWING THICKNESSES CONDUCIVE FOR SNOW. HOWEVER...A CLOSER EXAMINATION OF THE FORECAST SOUNDINGS FROM THE EC SHOWS SURFACE TEMPS IN THE UPPER 30S FRIDAY MORNING. ALSO THE GROUND SHOULD BE FAIRLY WARM SINCE HIGHS ON WED AND THURSDAY WILL BE NEAR 60. SO IF THE EC DOES VERIFY WITH THE MID LEVEL WAVE...WOULD EXPECT ANY PRECIP THAT OCCURS TO BE MORE OF A COLD RAIN. OF COURSE THIS WILL NEED TO BE MONITORED OVER THE NEXT FEW DAYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1223 PM CDT MON OCT 14 2013 SHOWERS AND A FEW THUNDERSTORMS ARE GOING TO BE MOVING THROUGH THE KGRI TERMINAL AREA THIS AFTERNOON AND EARLY THIS EVENING BUT SHOULD BE OUT OF THE AREA LATER THIS EVENING. IFR CEILINGS ARE EXPECTED THROUGH THE AFTERNOON BUT SHOULD LIFT AS THE THUNDERSTORMS MOVE THROUGH THE AREA. A COLD FRONT WILL MOVE THROUGH THE AREA THIS EVENING TURNING WINDS FROM SOUTH TO NORTHWEST. IN ADDITION WINDS WILL BE FAIRLY STRONG DURING THE NIGHT. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...PFANNKUCH LONG TERM...EWALD AVIATION...JCB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1222 PM CDT MON OCT 14 2013 .AVIATION... 18Z TAFS FOR KOFK...KOMA AND KLNK. BANDS OF SHOWERS/TSTMS WILL CONTINUE TO ROTATE ACROSS ERN NEBRASKA AS A STRONG UPPER SYSTEM MOVES INTO ERN SD BY EARLY TONIGHT. DRIER AIR OVER WRN IA WAS KEEPING CIGS/VSBYS A BIT HIGHER AT KLNK/KOMA BUT BOTH SHOULD BE LOWERING AS LOW LEVEL MOISTURE WORKS EAST LATER THIS AFTN/EARLY EVENING AND STRONGER CONVECTIVE LINES ALSO MOVE EAST. BULK OF CONVECTION SHOULD BE SHIFTING EAST OF TAF SITES BY 02-04Z. STRONG LOW LEVEL JET COULD BRING A PERIOD OF LOW LEVEL WIND SHEAR EARLY AND COULD ALSO PROVIDE SOME STRONG WIND GUSTS IN STRONGER THUNDERSTORMS THROUGH EARLY EVENING. WRLY WINDS BEHIND COLD FRONT THIS EVENING COULD LIMIT SRN EXTENSION OF LOWER CIGS UNTIL LATER IN TAF PERIOD...BUT MVFR CIGS WERE MAINTAINED IN OUT PERIOD FOR NOW. CHERMOK && .PREV DISCUSSION... /ISSUED 355 AM CDT MON OCT 14 2013/ DISCUSSION... MAIN FORECAST CHALLENGE IS TIMING THE RAIN TODAY THROUGH TUESDAY...AND DETERMINING RAINFALL AMOUNTS. AT 08Z...SHOWERS WITH A FEW THUNDERSTORMS WERE MOVING THROUGH PARTS OF NEBRASKA...THEN EXTENDED SOUTHWEST THROUGH COLORADO AND INTO NORTHERN NEW MEXICO. THIS AREA OF PRECIPITATION WAS IN RESPONSE TO A DEEP UPPER LOW SPINNING OVER UTAH PER WATER VAPOR IMAGERY. ASSOCIATED WITH THE LOW WAS AN IMPRESSIVE JET MAX OF AROUND 145 KNOTS AS INDICATED BY THE RAP MODEL ANALYSIS NEAR THE COLORADO- NEW MEXICO BORDER. NUMEROUS LIGHTNING STRIKES WERE NOTED WITHIN THIS PRECIPITATION AREA. THE SURFACE CYCLOGENESIS RESPONSE TO THE UPPER LOW WAS MAXIMIZED FROM SOUTHEAST WYOMING INTO SOUTHWEST SOUTH DAKOTA WHERE 3 HOURLY PRESSURE FALLS WERE 2-3MB. BASED ON THE 100 METER 500MB HEIGHT RISES ON THE BACK SIDE OF THE UPPER TROUGH...THE EXPECTED SCENARIO IS FOR THE UPPER LOW TO MOVE FROM UTAH INTO THE NEBRASKA PANHANDLE BY THIS AFTERNOON. THAT WILL PIVOT THE JET AXIS TO A MORE EAST-WEST ORIENTATION...POSITIONING IT ACROSS SOUTHEAST COLORADO-SOUTHERN KANSAS. EXPECT STRONG UPWARD FORCING DUE TO A COMBINATION OF: THE UPPER DIVERGENCE FROM THE LEFT FRONT EXIT REGION OF THE JET MAX...STRONG DPVA AHEAD OF THE UPPER LOW...ISENTROPIC LIFT IN THE WARM CONVEYER BELT REGION...AND CONTINUED SURFACE CYCLOGENESIS. ALL OF THIS POINTS TO A WELL-DEFINED EXTRATROPICAL CYCLONE PATTERN MOVING THROUGH THE PLAINS TODAY AND THIS EVENING...WITH A SURFACE COLD FRONT MOVING THROUGH EASTERN NEBRASKA AND SOUTHWEST IOWA TONIGHT. IN THESE SCENARIOS WE CAN PLAN ON SOMEWHAT HEAVY RAINS AHEAD OF THE LOW DURING THE DAY TODAY AND INTO THE EVENING...THEN THE DRY SLOT PUSHING INTO THE REGION OVERNIGHT TONIGHT. THEN AS THE UPPER LOW MOVES NORTHEAST OF THE REGION...SCATTERED SHOWERS SHOULD OCCUR ON THE BACK SIDE OF THE LOW IN THE DEFORMATION ZONE. RAINFALL AMOUNTS OF 2 INCHES WILL BE POSSIBLE NEAR THE SOUTH DAKOTA BORDER...WITH CLOSER TO 0.5 INCH NEAR THE MISSOURI BORDER...AND 1-1.5 INCHES NEAR I-80. THESE AMOUNTS ARE SUPPORTED BY FAIRLY GOOD MODEL AGREEMENT WITH THE OVERALL PATTERN AS WELL AS THE MODEL RAINFALL. THIS ACTIVE PATTERN SHOULD BE ACCOMPANIED BY A STRONG SOUTHERLY LOW LEVEL JET OF AROUND 60 KNOTS THIS AFTERNOON AND EVENING...THEN 40-45 KNOTS OUT OF THE NORTHWEST TUESDAY. THUNDERSTORMS THAT DEVELOP ON THE EASTERN EDGE OF THE DRY SLOT OVER SOUTH CENTRAL NEBRASKA THIS AFTERNOON/EVENING MAY BE QUITE STRONG AND COULD MOVE NORTHEAST INTO AREAS GENERALLY WEST AND SOUTH OF NORFOLK. BEHIND THE COLD FRONT...TEMPERATURES WILL BE ABOUT 10 DEGREES COLDER TUESDAY THAN TODAY WITH GUSTY NORTHWEST WINDS...CLOUDS...AND SCATTERED LIGHT SHOWERS ESPECIALLY IN NORTHEAST NEBRASKA. SURFACE HIGH PRESSURE MOVES IN WEDNESDAY WITH COOL/QUIET WEATHER. THE PATTERN OVER NORTH AMERICA SETTLES INTO A HIGH AMPLITUDE RIDGE ALONG THE WEST COAST WITH A BROAD LONGWAVE TROUGH FROM HUDSON BAY INTO THE SOUTHERN US...AND THIS KEEPS THE CENTRAL PLAINS IN A COOL NORTHWEST FLOW REGIME INTO NEXT WEEK. NIETFELD && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
301 PM CDT MON OCT 14 2013 .SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT) ISSUED AT 215 PM CDT MON OCT 14 2013 FOCUS OF THE FORECAST CONTINUES TO BE ON THE INCOMING SYSTEM AND RAIN CHANCES INTO WEDNESDAY. HIGH PRESSURE AT THE SURFACE HAS PUSHED EAST TO OVER EASTERN LAKE SUPERIOR AND LOWER MICHIGAN AS LOW PRESSURE HAS DEVELOPED IN THE LEE OF THE ROCKIES OVER WESTERN NEBRASKA. THE LOW HAS FORMED IN THE RESPONSE THE UPPER LEVEL LOW THAT IS OVER EASTERN WYOMING. THE 14.12Z MODELS CONTINUE TO BE IN EXCELLENT AGREEMENT ON THE HANDLING OF THIS SYSTEM WHICH LEADS TO HIGH CONFIDENCE ON THE OUTCOME. THE UPPER LEVEL LOW WILL MOVE NORTHEAST INTO THE UPPER MIDWEST TONIGHT INTO TUESDAY. AS IT DOES...IT WILL TAKE ON A POSITIVE TILT AS IT BECOMES ENTRAINED INTO THE MEAN LONG WAVE TROUGH EMANATING FROM THE STRONG CLOSED UPPER LEVEL LOW OVER HUDSONS BAY. EVEN AS THIS IS OCCURRING...THE MAIN SHORT WAVE TROUGH WITH THE WYOMING LOW IS FORECAST TO REMAIN STRONG AND BRING BETWEEN 8 AND 16 PVU/S OF VORTICITY ADVECTION IN THE 500 TO 300 MB LAYER ACROSS THE AREA LATE TONIGHT INTO EARLY TUESDAY MORNING. THIS CREATES STRONG AND DEEP QG CONVERGENCE IN THE 1000-300 MB LAYER OVERNIGHT WITH THIS THEN MOVING OFF TO THE NORTHEAST TUESDAY MORNING. EXCELLENT ISENTROPIC UP GLIDE IS EXPECTED TO OCCUR WITH THE MODELS SHOWING BETWEEN 4 AND 6 UBAR/S ON THE 295K SURFACE ALONG WITH THE MOISTURE TRANSPORT ON THIS LEVEL BEING INTO THE NORTHERN HALF OF THE FORECAST AREA THROUGH 12Z TUESDAY. ALL THIS FORCING WILL BE MORE THAN SUFFICIENT TO OVERCOME THE DRY AIR BROUGHT IN BY THE DEPARTING SURFACE HIGH AND EXPECT TO SEE RAIN SHOWERS OVERSPREAD THE AREA AFTER 03Z OR SO AND HAVE SPREAD 90 TO 100 PERCENT RAIN CHANCES ACROSS THE AREA TONIGHT. AS THE SHORT WAVE TROUGH STARTS TO MOVE OFF TUESDAY...THE SURFACE LOW IS EXPECTED TO MOVE FROM CENTRAL MINNESOTA INTO NORTHERN WISCONSIN ALLOWING THE DRY SLOT TO EITHER APPROACH THE AREA OR MOVE INTO THE SOUTHERN SECTIONS TUESDAY AFTERNOON WITH THE MAIN BAND OF RAIN BECOMING ORIENTED INTO THE DEFORMATION BAND ON THE BACK SIDE OF THE SURFACE LOW. THIS DEFORMATION BAND WILL THEN MOVE ACROSS THE NORTHERN SECTIONS OF THE FORECAST AREA TUESDAY EVENING AND WILL SHOW 50 TO 70 PERCENT RAIN CHANCES NORTH OF I90 FOR THIS. THE WHOLE SYSTEM WILL THEN EXIT THE REGION WEDNESDAY AND JUST HELD ON TO SOME LINGERING CHANCES ACROSS THE EAST DURING THE MORNING BEFORE GOING DRY WEDNESDAY AFTERNOON. .LONG TERM...(THURSDAY THROUGH MONDAY) ISSUED AT 215 PM CDT MON OCT 14 2013 THE CLOSED LOW WILL REMAIN OVER HUDSONS BAY AND LOOKS TO SWING ANOTHER SHORT WAVE TROUGH...SURFACE LOW PRESSURE AREA AND COLD FRONT ACROSS THE UPPER MIDWEST AND GREAT LAKES TOWARD THE END OF THE WEEK. THERE COULD ALSO BE ANOTHER SYSTEM COMING THROUGH TO OVER THE WEEKEND. WITH THESE SYSTEMS...WILL SHOW SOME SMALL PRECIPITATION CHANCES...MAINLY 20 TO 30 PERCENT...FROM THURSDAY NIGHT THROUGH SATURDAY AND AGAIN FOR SUNDAY NIGHT AND MONDAY. WITH THE PASSAGE OF THE FIRST COLD FRONT...TEMPERATURES COULD GET COLD ENOUGH FOR SOME OF THE PRECIPITATION TO FALL AS SOME SNOW AND HAVE INCLUDED THIS ACROSS THE NORTH FOR FRIDAY NIGHT. OTHERWISE...TEMPERATURES WILL GENERALLY BE COOLING DOWN TO BE BELOW NORMAL WITH HIGHS IN THE 40S AND 50S AND LOWS IN THE 30S. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 300 PM CDT MON OCT 14 2013 A LOW PRESSURE SYSTEM...CURRENTLY LOCATED OVER EASTERN NEBRASKA... WILL MOVE NORTHEAST ACROSS WESTERN IOWA AND SOUTH CENTRAL MINNESOTA THROUGH TUESDAY MORNING. AS THIS LOW APPROACHES THE AREA OF BAND OF SHOWERS WILL MOVE INTO KRST AROUND 15.03Z AND KLSE AROUND 15.06Z. WITH DRY AIR IN PLACE ACROSS THE REGION...IT WILL TAKE ABOUT 3 HOURS BEFORE THE CEILINGS WILL BECOME IFR/MVFR. THE CEILINGS WILL THEN LIKELY STAY THERE THROUGH THE REMAINDER OF TUESDAY MORNING. EXPECT THE VISIBILITIES TO BECOME MVFR AT KRST ABOUT THE SAME TIME THAT THE CEILINGS BECOME IFR...BUT WAS NOT AS CONFIDENT TO DO THE SAME AT KLSE....SO LEFT THEM OUT FOR NOW. WHILE THE BAND OF PRECIPITATION WILL BE NARROW...THE MODELS CONTINUE TO STRUGGLE ON WHEN THIS PRECIPITATION MIGHT END. THE LATEST RAP SUGGESTS THAT THIS WOULD OCCUR AT KRST BY 10Z AT KRST AND 13Z AT KLSE. HOWEVER THE NMM AND ARW SHOW THAT THIS PRECIPITATION WILL CONTINUE THROUGH THE MORNING. SINCE IT WAS UNCLEAR...WENT WITH A COMPROMISE AND ENDED IT AROUND 15.14Z AT KRST. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...04 LONG TERM...04 AVIATION...BOYNE
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE

.SHORT TERM...TONIGHT AND TUESDAY ISSUED AT 233 PM CDT MON OCT 14 2013 LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE CENTERED OVER THE CENTRAL GREAT LAKES WHILE LOW PRESSURE IS DEVELOPING IN THE LEE OF THE ROCKIES. PLENTY OF HIGH CLOUDS ARE ALREADY ADVANCING ACROSS THE NORTHWEST HALF OF THE STATE THIS AFTERNOON. FAIRLY WIDESPREAD AREA OF SHOWERS AND ALSO SOME THUNDER AHEAD OF THE LOW AS WELL OVER THE PLAINS. AS THE LOW MOVES NE TOWARDS THE REGION...PRECIP TIMING AND IMPACTS ARE THE MAIN FORECAST CONCERNS. TONIGHT...LOW PRESSURE OVER THE CENTRAL PLAINS WILL MOVE NORTHEAST TO SOUTHWEST MINNESOTA BY 12Z TUESDAY. AHEAD OF THE LOW...PLENTY OF DRY AIR IN THE LOW AND MID-LEVELS WILL INITIALLY KEEP THE COLUMN FROM SATURATING...SO WILL CONTINUE TO PORTRAY DRY CONDITIONS THROUGH THE EVENING. HIGH CLOUDS WILL BE INCREASING THOUGH ALONG WITH A STEADY EAST WIND WHICH WILL MAKE THE NIGHT RATHER CHILLY. BY LATE TONIGHT...INCREASING UPPER DIVERGENCE AND THE ARRIVAL OF THE WARM CONVEYOR BELT WILL BRING AN INCREASING THREAT OF PRECIP. A 40-50KT LLJ WILL TRANSPORT MOISTURE FROM AN OPEN GULF OF MEXICO WHICH WILL BRING IN PWATS UPWARDS OF AN INCH BY 09Z. SHOULD SEE A PRETTY SOLID PRECIP BAND ARRIVE BETWEEN 09-12Z OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. WITH A BRISK EAST WIND AND INCREASING CLOUDS...LOWS WILL BE WARMER AND MAINLY IN THE 40S. TUESDAY...THE LOW PRESSURE SYSTEM WILL CONTINUE TO MOVE NORTHEAST TO NORTH-CENTRAL WISCONSIN BY 00Z WED. THE WARM CONVEYOR BELT WILL ALSO MOVE IN THE NE DIRECTION ACROSS THE FORECAST AREA DURING THE MORNING...WHICH WILL GIVE THE ENTIRE AREA A DECENT CHANCE OF SEEING A QUARTER TO A HALF INCH (OR MORE) OF RAINFALL. THOUGH ELEVATED INSTABILITY IS PROGGED TO REMAIN UNDER 100 J/KG...DO NOT THINK WE CAN RULE OUT A LIGHTNING STRIKE OR TWO ALONG THE LEADING EDGE OF THE DRY SLOT. WILL KEEP A MENTION IN THE FORECAST. PLENTY OF WIND ALOFT TO BE BROUGHT DOWN BY ANY CONVECTIVE SHOWERS SO WILL LEAVE A MENTION IN THE HWO. A DRY SLOT WILL THEN MOVE ACROSS THE REGION DURING THE AFTERNOON ABOVE THE SURFACE COLD FRONT. PROGGED SOUNDINGS SHOW THE MID-LEVELS DRYING OUT ABOVE 700MB WHERE A DECENT CAP WILL DEVELOP. AS A RESULT...THINK WILL SEE AN ISOLATED LIGHTNING STRIKE AT BEST ALONG THE FRONT...THOUGH ANY SHOWERS COULD STILL BRING A DECENT WIND GUST. HIGHS AROUND 50 NORTH TO THE UPPER 50S SOUTH. .LONG TERM...TUESDAY NIGHT THROUGH MONDAY ISSUED AT 233 PM CDT MON OCT 14 2013 NO NOTABLE CHANGES TO PREVIOUS FORECAST WITH WESTERN GREAT LAKES GENERALLY UNDER THE INFLUENCE OF MEAN LONGWAVE TROUGH INTO EARLY NEXT WEEK. THIS PATTERN WILL SPELL A GENERALLY UNSETTLED PERIOD WITH TEMPERATURES BELOW NORMAL FOR MID OCTOBER. WILL STILL BE DEALING WITH WEAKENING LOW PRESSURE SYSTEM AND ATTENDANT SW-NE ORIENTATED DEFORMATION ZONE ON TUESDAY NIGHT. STILL SOME UNCERTAINTY WITH RESPECT TO TIMING AND NORTHERN PENETRATION OF DRY SLOT AS SURFACE LOW PASSES ACROSS THE FORECAST AREA. OVERALL MODEL CONSENSUS SUGGESTS THAT SWATH OF HEAVIEST PRECIPITATION ON NORTHEAST QUADRANT OF THE SYSTEM SHOULD BE EXITING THE NORTHEAST THIRD OF THE FORECAST AREA BY AROUND 00Z WEDNESDAY...WITH MID-LEVEL DRY INTRUSION PUSHING NORTHWARD TO ABOUT THE HIGHWAY 29 CORRIDOR SOMETIME BETWEEN 00Z AND 06Z TUESDAY NIGHT. THIS SCENARIO WOULD SUGGEST THAT THE MORE PERSISTENT LIGHT TO MODERATE RAINFALL WILL EXIST MAINLY NORTH OF THIS LINE. WOULD EXPECT A BRIEF LULL IN THE PRECIPITATION OVER THE FOX VALLEY AND/OR SOME DRIZZLE FOR A TIME TUESDAY EVENING. REMANANTS OF ERODING DEFORMATION ZONE...AND ASSOCIATED SCATTERED SHOWER ACTIVITY TO SWING ACROSS THE FORECAST AREA AFTER MIDNIGHT. UPPER TROUGH AXIS AND ASSOCIATED SECONDARY SURFACE REFLECTION STILL ON TRACK TO PUSH ACROSS THE FORECAST AREA WEDNESDAY MORNING. ENOUGH FORCING WITH THIS FEATURE IN CONCERT WITH RESIDUAL MOISTURE TO KEEP HIGH-END CHANCE POPS GOING THROUGH ABOUT MIDDAY AS PER PREVIOUS FORECAST. WILL FEEL RATHER FALL-LIKE ON WEDNESDAY WITH BRISK NORTHWEST WINDS AND MOSTLY CLOUDY SKIES LENDING TO DAYTIME HIGHS MAINLY IN THE LOW TO MID 50S. VERY WEAK RIDGING AND SUFFCIENTLY DRY AIRMASS SHOULD BRING A DRY DAY ON THURSDAY WITH PERHAPS A SLIGHT INCREASE IN MAX TEMPS UNDER PARTLY SUNNY SKIES. WILL START OUT RATHER COOL HOWEVER WITH TEMPERATURES EARLY THURSDAY MORNING FALLING BELOW FREEZING ACROSS THE NORTH WITH SOME FROST AGAIN POSSIBLE ACROSS THE FOX VALLEY. CONFIDENCE WANES AS WE GET INTO THE UPCOMING WEEKEND AS DEEPENING UPPER TROUGH SETTLES OVER HUDSON BAY EJECTING WEAK DISTURBANCES SOUTHEASTWARD TOWARD THE WESTERN GREAT LAKES. DID NOT FEEL COMFORTABLE TRYING TO TWEAK TIMING SO PRETTY MUCH LEFT PREVIOUS FORECAST ALONE. STILL APPEARS WEAK FRONTAL SYSTEM WILL BRING SOME SCATTERED SHOWERS LATE FRIDAY INTO SATURDAY AND AGAIN SUNDAY NIGHT INTO MONDAY. MIGHT BE ABLE TO SQUEEZE OUT A MAINLY DRY DAY ON SUNDAY...BUT MUCH TOO EARLY TO BANK ON THAT. SOMEWHAT MORE CONFIDENT ON TEMPERATURES WITH READING CONTINUING TO SLIDE TO BELOW NORMAL VALUES WITH DAYTIME HIGHS BOTH SATURDAY AND SUNDAY IN THE 45 TO 50 DEGREE RANGE. && .AVIATION...FOR 18Z TAF ISSUANCE ISSUED AT 1230 PM CDT MON OCT 14 2013 VFR CONDITIONS TO PERSIST THROUGH THE EVENING...THOUGH MID AND HIGH CLOUDS WILL BE INCREASING FROM THE WEST OVER THIS TIME. THE LATEST GUIDANCE SUGGESTS RAIN WILL BEGIN MOVING INTO CENTRAL AND NORTH-CENTRAL WISCONSIN AFTER 09Z TONIGHT...AND THEN INTO EASTERN WISCONSIN BY AROUND 12Z. AS THE RAIN ARRIVES...GUIDANCE AND UPSTREAM OBS SHOW CIGS/VSBYS FALLING TO IFR/MVFR LEVELS...WHICH WILL HANG AROUND THROUGH THE END OF THE TAF PERIOD. LOW LEVEL WIND SHEAR TO ALSO DEVELOP LATE TONIGHT AHEAD OF A SURFACE LOW. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......ESB AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1243 PM CDT MON OCT 14 2013 .UPDATE... ISSUED AT 745 AM CDT MON OCT 14 2013 THE FROST ADVISORY WILL BE ALLOWED TO EXPIRE AT 8 AM. WIDESPREAD FROST HAS OCCURRED OVER THE ADVISORY AREA WITH EARLY MORNING TEMPERATURES PLUMMETING INTO THE MID 20S TO LOWER 30S. TEMPERATURES ARE EXPECTED TO WARM TO ABOVE FREEZING THROUGH 9 AM. && .SHORT TERM...(TODAY THROUGH WEDNESDAY) ISSUED AT 230 AM CDT MON OCT 14 2013 SHORTWAVE ENERGY WAS DRIVING THROUGH THE MEAN TROUGH OVER THE ROCKIES EARLY THIS MORNING...PER LATEST WATER VAPOR SATELLITE IMAGERY. THE TROUGH WILL LIFT NORTHEAST TODAY AS A 300 MB JET ROUNDS ITS BASE AND HEADS TOWARD THE GREAT LAKES. GOOD AGREEMENT BETWEEN THE GFS/NAM/ECMWF WITH PLACING THE 500 MB LOW OVER SOUTHERN MN BY 18Z TUE...MORE OR LESS VERTICALLY STACKED WITH THE ASSOCIATED SFC LOW AT THIS TIME. STRONG QG RESPONSE...DEEPER AND STRONGER OVER SOUTHERN MN/NORTHWEST WI FROM 06Z-18Z TUE. THERMODYNAMICS ARE EQUALLY HEFTY...WITH A STRONG PUSH OF 925-700 MB WARM AIR ADVECTION AS THE SYSTEM MOVES IN...ALONG WITH RISING AIR ALONG THE 290-305 K ISENTROPIC SFCS. THE LEFT EXIT REGION OF THE 300 MB JET WILL ENHANCE THE ALREADY APPRECIABLE LIFT...MOSTLY IN THE DEFORMATION REGION OF THE STORM SYSTEM. MEANWHILE...FRONTOGENETIC RESPONSE IS GOOD ALONG THE SYSTEM/S SOUTHWARD HANGING COLD FRONT...WITH A 50 KT LOW LEVEL JET SURGING MOISTURE NORTHWARD ALONG THE FRONT...THEN WRAPPED WESTWARD AROUND THE LOW. ITS GOING TO RAIN. MODELS IN GOOD AGREEMENT WITH PCPN ENCROACHING UPON AREAS WEST OF THE MISSISSIPPI LATE THIS EVENING...SPREADING INTO WESTERN WISCONSIN OVERNIGHT. THE FRONTAL/MOISTURE TRANSPORT BAND OF PCPN SHIFTS ACROSS EASTERN WI BY LATE MORNING WHILE THE DEFORMATION BAND NORTH-WEST OF THE SFC LOW HANGS FROM SOUTHERN MN TO ACROSS THE UP OF MICH. THIS REGION WILL SHIFT EASTWARD AND ACROSS THE FORECAST AREA FOR THE AFTERNOON THROUGH NIGHTTIME HOURS. COULD BE A BREAK IN THE PCPN WITH A DRY 850-700 MB PUNCH OF AIR POST THE SFC FRONT. WILL CONTINUE TO PLAY THIS TREND IN THE PCPN CHANCES. ON WED...A LINGERING WESTWARD EXTENDING SFC TROUGH AND A BIT OF UPPER LEVEL ENERGY COULD CONTINUE TO SCATTERED LIGHT RAIN SHOWERS FOR THE MORNING EAST OF THE MISSISSIPPI RIVER. .LONG TERM...(THURSDAY THROUGH SUNDAY) ISSUED AT 230 AM CDT MON OCT 14 2013 GFS/EC IN GOOD AGREEMENT WITH AN UPPER LEVEL LOW SETTING UP SHOP OVER HUDSON/S BAY FOR THE LATER HALF OF THE WEEK...WITH A TROUGH REESTABLISHING ITSELF OVER THE GREAT LAKES. LOCALLY...THIS PUTS THE REGION UNDER NORTHWEST FLOW THROUGH THE WEEKEND...WITH VARIOUS BITS OF UPPER LEVEL ENERGY AND LOW LEVEL COLD AIR ADVECTION. THIS WILL RESULT IN PERIODIC LIGHT RAIN CHANCES...ESPECIALLY ACROSS NORTHERN PORTIONS OF MN/WI. CHANCES WILL BE HIGHER WITH THE PASSAGE OF ANY SHORTWAVE TROUGH/SFC FRONT COMBO. NOTHING OVERLY DYNAMIC AT THIS TIME...AND CAN/T FERRET OUT A MORE LIKELY PERIOD THIS FAR OUT. WILL SIDE WITH CONSENSUS FOR PCPN CHANCES. 850 MB TEMPS WILL TUMBLE TO -6 C FOR THE WEEKEND...WITH ECMWF 850 MB TEMP ANOMALIES FROM -1 TO -1.5. ITS GOING TO BE A COOL LAST HALF OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON) ISSUED AT 1242 PM CDT MON OCT 14 2013 A LOW PRESSURE SYSTEM...CURRENTLY LOCATED OVER EASTERN NEBRASKA... WILL MOVE NORTHEAST ACROSS WESTERN IOWA AND SOUTH CENTRAL MINNESOTA THROUGH TUESDAY MORNING. AS THIS LOW APPROACHES THE AREA OF BAND OF SHOWERS WILL MOVE INTO KRST AROUND 15.03Z AND KLSE AROUND 15.06Z. WITH DRY AIR IN PLACE ACROSS THE REGION...IT WILL TAKE ABOUT 3 HOURS BEFORE THE CEILINGS WILL BECOME IFR/MVFR. THE CEILINGS WILL THEN LIKELY STAY THERE THROUGH THE REMAINDER OF TUESDAY MORNING. EXPECT THE VISIBILITIES TO BECOME MVFR AT KRST ABOUT THE SAME TIME THAT THE CEILINGS BECOME IFR...BUT WAS NOT AS CONFIDENT TO DO THE SAME AT KLSE....SO LEFT THEM OUT FOR NOW. WHILE THE BAND OF PRECIPITATION WILL BE NARROW...THE MODELS CONTINUE TO STRUGGLE ON WHEN THIS PRECIPITATION MIGHT END. THE LATEST RAP SUGGESTS THAT THIS WOULD OCCUR AT KRST BY 10Z AT KRST AND 13Z AT KLSE. HOWEVER THE NMM AND ARW SHOW THAT THIS PRECIPITATION WILL CONTINUE THROUGH THE MORNING. SINCE IT WAS UNCLEAR...WENT WITH A COMPROMISE AND ENDED IT AROUND 15.14Z AT KRST. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...WETENKAMP SHORT TERM...RIECK LONG TERM....RIECK AVIATION...BOYNE