Forecast Discussions mentioning any of "HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 10/05/13


AREA FORECAST DISCUSSION
NWS TAUNTON MA
731 PM EDT FRI OCT 4 2013 .SYNOPSIS... A STALLED FRONT WILL REMAIN NEAR THE NEW ENGLAND SOUTH COAST THROUGH SATURDAY. A WEAK WAVES OF LOW PRESSURE WILL MOVE ALONG THE FRONT TONIGHT INTO SATURDAY...WHICH MAY BRING ANOTHER ROUND OF SHOWERS. THE FRONT WILL THEN WILL LIFT SLOWLY NORTH DURING SUNDAY...BRINGING WARMER TEMPERATURES MONDAY. THERE WILL A BETTER CHANCE OF WIDESPREAD SHOWERS EARLY NEXT WEEK AS A COLD FRONT SLOWLY MOVES ACROSS NEW ENGLAND. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 715 PM UPDATE...COVERAGE OF SHOWERS ACROSS SOUTHERN NEW ENGLAND CONTINUES TO DIMINISH THIS EVENING. LATEST NEAR-TERM MODEL GUIDANCE...INCLUDING THE LAST FEW RUNS OF BOTH THE HRRR AND RAP... APPEAR TO HAVE A VERY GOOD HANDLE ON CONVECTION MOVING ACROSS EASTERN NY STATE. WILL USE THOSE MODELS TO TWEAK RAINFALL CHANCES FOR THE NEXT FEW HOURS. OTHERWISE...PLENTY OF CLOUDS AND LIGHT WINDS WILL LIKELY MEAN TEMPERATURES WILL NOT CHANGE MUCH. ADJUSTED TEMPERATURES BASED ON OBSERVED TRENDS FOR THIS EVENING. PREVIOUS DISCUSSION... MAIN AREA OF SHOWERS CONTINUING TO MOVE E OF CAPE COD AT 20Z. MAY SEE SOME BRIEF HEAVY DOWNPOURS OVER THE NEXT COUPLE OF HOURS ACROSS THE CAPE. INTERESTING TO NOTE THAT WFO BOX RECEIVED 1.5 INCHES OF RAIN AS A COUPLE OF HEAVY SHOWERS PASS OVER THE STATION TODAY...WHILE ABOUT 8 MILES SE...KTAN AIRPORT ONLY 0.36 INCHES WAS REPORTED. NOTING BREAK IN CLOUD DECK ON VISIBLE SATELLITE...WITH SOME CLEARING ACROSS S CT AND S RI. NE RADAR MOSAIC SHOWING SCT SHOWERS/ISOLD TSTMS ACROSS CENTRAL AND SE NY/N NJ INTO SW CT NEAR AND S OF A STALLED FRONT AS AIRMASS DESTABILIZES. SOME MAY MOVE INTO CT VALLEY AND NE CT/W RI THROUGH THIS EVENING. CAN NOT RULE OUT ISOLD THUNDER...THOUGH NOT MENTIONED IN THE FORECAST FOR NOW. WEAK LOW PRES WILL ALSO MOVE ALONG THE STALLED FRONT LATER ON...SO HAVE KEPT CHANCE POPS GOING THROUGH THE NIGHT...WHICH WILL SHIFT TO THE S COAST AFTER MIDNIGHT. WILL CONTINUE TO SEE WIDE RANGE IN TEMPS INTO THIS EVENING AS E-NE WINDS BRING COOLER AIR OFF THE OCEAN N OF THE FRONT. CASE IN POINT...TEMP AT KFMH WAS 59 DEGREES WITH NE WINDS AT 19Z...WHILE 75 DEGREES WITH LIGHT/VRBL WINDS AT KMVY. AFTER SUNSET...TEMPS WILL DROP BACK TO THE 50S...POSSIBLY A FEW UPPER 40S ACROSS NORTHERN CHESHIRE AND HILLSBOROUGH COUNTIES. WILL ALSO SEE SOME PATCHY FOG DEVELOP IN THE NORMALLY PRONE VALLEY AREAS OF INTERIOR E MA AND THE CT VALLEY INTO NE CT. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... SATURDAY... UPPER LEVEL RIDGING STARTS TO BUILD IN WITH THE STALLED FRONT RUNNING PARALLEL TO IT. WEAK FRONTAL WAVE WILL SHIFT OFFSHORE AS SURFACE RIDGE BUILDS OVER NORTHERN NEW ENGLAND. SHORT RANGE MODELS ALL SIGNAL DRYING WORKING IN FROM THE N DURING THE DAY...THOUGH THE FRONT DOES REMAIN STALLED NOT TOO FAR AWAY. WENT WITH ONLY SLIGHT CHANCE POPS EARLY IN THE DAY WHICH SHOULD DRY OUT. CLOUDS WILL LINGER INTO THE AFTERNOON...THEN SHOULD BREAK UP. WILL BE RATHER MUGGY ALONG THE S COAST...CAPE AND ISLANDS AS DEWPTS HOVER CLOSE TO 60 NEAR THE FRONT. TEMPS SHOULD REACH AROUND 70 ACROSS MOST OF THE REGION. SATURDAY NIGHT... MODELS INDICATING THAT THE FRONT MAY TRY TO MAKE A RUN DURING THIS TIMEFRAME...THOUGH SHOULD REMAIN S OF THE REGION THROUGH THE NIGHT. NOT MUCH IN THE WAY OF PRECIP WITH THIS. ANOTHER WEAK LOW MAY MOVE ALONG THE FRONT AFTER MIDNIGHT...WITH ANOTHER SHOT FOR PRECIP TOWARD DAYBREAK. KEPT DRY FOR MOST OF THE NIGHT...THOUGH WILL LIKELY SEE ANOTHER ROUND OF FOG DEVELOPING LATE AT NIGHT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... HIGHLIGHTS... * TEMPERATURES AT OR WARMER THAN NORMAL * UNSETTLED BUT NOT A WASHOUT SUNDAY * WIDESPREAD SHOWERS WITH LOCALLY HEAVY RAIN POSSIBLE MON/TUE SYNOPTIC OVERVIEW... A WARM FRONT WILL BE LIFTING NORTH THROUGH THE REGION SUNDAY AS ITS PARENT LOW EXITS THE GREAT LAKES INTO ONTARIO. THE ATTENDING COLD FRONT WILL BE PROGRESSIVE AND SWEEP ACROSS NEW ENGLAND SOMETIME MON/TUE. THIS FRONT WILL MOVE OFFSHORE LATER TUE WITH CONFLUENT FLOW ALOFT AND HIGH PRESSURE AT THE SURFACE BUILDING INTO NEW ENGLAND LATER TUE INTO WED/THU. THIS MAY LEAVE THE REMNANTS OF TROPICAL STORM KAREN MEANDERING SOMEWHERE OVER THE SOUTHEAST STATES NEXT WEEK. MODELS/GUIDANCE... WITH THE EXCEPTION OF THE 12Z CMC...THERE IS GOOD AGREEMENT WITH THE OVERALL SYNOPTIC PATTERN AMONG THE MEMBERS OF THE 12Z GUIDANCE SUITE. MODELS ARE STARTING TO SLOW THE PASSAGE OF A COLD FRONT FROM EARLY TUESDAY...TO SOMETIME TUESDAY NIGHT INTO WEDNESDAY. CONFIDENCE WITH THIS TIMING IS BELOW AVERAGE...GIVEN THE RUN-TO-RUN INCONSISTENCIES. THE SLOWER TIMING OF A COLD FRONT WOULD MEAN LESS PHASING OF THE MOISTURE FROM REMNANTS OF KAREN WITH THE FORCING OF THIS FRONT. THUS DESPITE THE POTENTIAL FOR 1-2 INCHES OF RAIN SOMEWHERE...THERE IS NOT MUCH CONFIDENCE TO SAY EXACTLY WHERE AND WHEN JUST YET. THE TREND CONTINUES WHERE IT WOULD BE LESS LIKELY TO BE SOMEWHERE IN SOUTHERN NEW ENGLAND. SENSIBLE WEATHER... SUNDAY...A WARM FRONT LIFTS ACROSS AND NORTH OF OUR REGION. DEEP LAYER MOISTURE AND LIFT ARE LACKING...SO THINKING ANY SHOWER ACTIVITY WILL BE SPOTTY AND NOT WIDESPREAD. HENCE MANY HOURS OF DRY WEATHER. COOLER AS WARM SECTOR MAY NOT OVERSPREAD THE REGION UNTIL SUNDAY NIGHT OR MONDAY. MONDAY/TUESDAY...A PERIOD OF SHOWERS WITH LOCALLY HEAVY RAIN APPEARS LIKELY. DEPARTURE TIME OF SHOWERS STILL SOMEWHAT UNCERTAIN. MILD TO WARM WITH A COLD FRONT LIKELY NOT CROSSING OUR REGION UNTIL LATE TUESDAY OR TUESDAY NIGHT. WEDNESDAY/THURSDAY...MODEL CONSENSUS CONTINUES WITH A DRYING TREND AS A HIGH PRESSURE IS EXPECTED TO BUILD TOWARD NEW ENGLAND FROM THE GREAT LAKES. THIS WOULD MEAN THE REMNANTS OF KAREN WOULD REMAIN WELL SOUTH OF NEW ENGLAND. COOLER BUT PROBABLY STILL NEAR OR SLIGHTLY WARMER THAN NORMAL. FRIDAY...HIGH PRESSURE SHOULD BE IN CONTROL WITH DRY WEATHER AND NEAR NORMAL TEMPERATURES. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY NIGHT/...MODERATE TO HIGH CONFIDENCE. TONIGHT...GENERALLY VFR CONDITIONS. SCT SHOWERS MAY PRODUCE LOCAL MVFR-IFR CONDITIONS ACROSS CENTRAL AND SOUTHERN AREAS EARLY TONIGHT...WHICH SHOULD DIMINISH AFTER MIDNIGHT. MAY ALSO SEE PATCHY FOG AFTER MIDNIGHT WITH IFR-LIFR CIGS/VSBYS IN NORMALLY PRONE AREAS. SATURDAY...ANY LEFTOVER SHOWERS WILL DIMINISH BY MIDDAY. MAINLY VFR. EARLY MORNING PATCHY FOG WILL DISSIPATE BY MID MORNING. SATURDAY NIGHT...MAINLY VFR CIGS. LOCAL MVFR-IFR CIGS/VSBYS AFTER MIDNIGHT IN PATCHY FOG IN NORMALLY PRONE AREAS. KBOS TERMINAL...HIGH CONFIDENCE VFR. LIGHT/VRBL WINDS BECOME E-NE TONIGHT AND SAT. LOW PROB OF MVFR CIGS/VSBYS TONIGHT/EARLY SAT WITH ONSHORE WINDS. KBDL TERMINAL...MAINLY VFR. MVFR CIGS POSSIBLE LATE TONIGHT INTO EARLY SAT. OUTLOOK...SUNDAY THROUGH WEDNESDAY... MODERATE CONFIDENCE. SUNDAY...VFR LIKELY WITH SPOTTY SHOWERS POSSIBLE...MAINLY DURING THE AFTERNOON ACROSS THE WESTERN HALF OF THE REGION. MONDAY/TUESDAY...A PERIOD OF MVFR/IFR POSSIBLE IN SHOWERS AHEAD OF AN APPROACHING COLD FRONT. WEDNESDAY...VFR LIKELY ACROSS THE INTERIOR...WITH A LOW PROBABILITY OF MVFR CONDITIONS TOWARD THE CAPE AND ISLANDS...ESPECIALLY EARLY. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SATURDAY NIGHT/...HIGH CONFIDENCE. EXPECT WINDS AND SEAS TO REMAIN BELOW SMALL CRAFT CRITERIA. SCT SHOWERS THROUGH THIS EVENING ACROSS THE EASTERN WATERS. PATCHY FOG POSSIBLE LATE TONIGHT AND SAT NIGHT WITH LOCAL VSBY RESTRICTIONS. OUTLOOK...SUNDAY THROUGH WEDNESDAY... SUNDAY...LIGHT SE WINDS WITH HIGH PRES OVER THE MARITIMES. SUNDAY NIGHT/MONDAY...INCREASING SSW WINDS WITH APPROACHING COLD FRONT. VSBY LIMITED IN SHOWERS AND FOG. ROUGH SEAS LIKELY DEVELOPING ACROSS THE OUTER COASTAL WATERS. MONDAY NIGHT/TUESDAY...COLD FRONTAL PASSAGE WITH REMNANTS OF TROPICAL STORM KAREN LIKELY REMAINING WELL SOUTH OF NEW ENGLAND. WEDNESDAY...WINDS DIMINISH SOME...WITH LINGERING ROUGH SEAS ACROSS THE OUTER COASTAL WATERS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...EVT/BELK NEAR TERM...BELK/EVT SHORT TERM...EVT LONG TERM...BELK AVIATION...EVT/BELK MARINE...EVT/BELK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1014 PM CDT FRI OCT 4 2013 .DISCUSSION... 804 PM CDT THIS EVENING...WARM FRONT STRETCHES FROM NEAR DBQ ESE TO JOT...THEN EAST TO VPZ. TEMPERATURES CONTINUE TO RUN IN THE MID TO UPPER 70S SOUTH OF THE FRONT...WITH DEWPOINTS INTO THE MID TO UPPER 60S. NORTH OF THE BOUNDARY...TEMPERATURES QUICKLY TAPER INTO THE MID 60S...WITH LOW DEW POINT DEPRESSIONS. FOG/LOW STRATUS ALREADY STARTING TO DEVELOP ACROSS THESE AREAS...AND SHOULD CONTINUE TO EXPAND OVERNIGHT. REMOVED PRECIP MENTION OVERNIGHT FOR ALL BUT THE NORTHERN TIER OF COUNTIES. LAST VISIBLE SATELLITE IMAGES BEFORE SUNSET SHOWED CU FIELD QUICKLY DISSIPATING...AND THE MAIN IMPETUS FOR ANY PRECIP OVERNIGHT IS NEAR THE IL/WI STATE LINE WHERE THE BEST FOCUSED ISENTROPIC ASCENT IS NOTED. FORECAST OTHERWISE ON TRACK WITH ONLY MINOR TWEAKS TO THE HOURLY TRENDS. DEUBELBEISS //PREV DISCUSSION... 240 PM FOR THE REMAINDER OF THE AFTERNOON THROUGH SATURDAY...THE MAIN CONCERN WILL BE SEVERE WEATHER POTENTIAL...WITH A SECONDARY CONCERN FOR TEMPERATURES. EARLY THIS AFTERNOON...CONVECTIVE ACTIVITY IS FOCUSING ON THE NOSE OF A STRONG LOW LEVEL JET POINTING INTO NRN IL...WHICH IS ENHANCING THE ISENTROPIC LIFT ALREADY IN PLACE AS WARM MOIST AIR CONTINUES TO STREAM INTO THE REGION. A SECONDARY FOCUS OF CONVECTIVE ACTIVITY IS A SFC TROUGH/SECONDARY WARM FRONT EXTENDING FROM NRN MO...THROUGH NRN IL AND NRN INDIANA. LATEST RADAR IMAGERY SHOWS THE WARM ADVECTION CONVECTION ALREADY INTO NWRN IL AND WITH COPIOUS AMOUNTS OF HEAT...TEMPS IN THE UPPERS 70S-LOW 80S...MOISTURE...DEWPOINTS IN THE UPPER 60S TO LOWERS 70S...AND INSTABILITY...MIXED LAYER CAPE OF 1500-2000 J/KG...EXPLOSIVE CONVECTION IS QUITE POSSIBLE WHERE ALL ELEMENTS LINE UP JUST RIGHT. WITH THE LOW LEVEL JET OF 30KT+ OVER THE AREA...STRONGER WINDS CAN CERTAINLY MIX DOWN TO THE SURFACE. THE ONE QUESTION MARK AT THIS TIME IS THE CLOUD COVER. LATEST SATELLITE IMAGERY SHOWS DENSE OVC OVER NRN IL...WITH MORE CONVECTIVELY DRIVEN CU/TOWERING CU SOUTH OF THE I-80 CORRIDOR. OF PARTICULAR CONCERN IS THE SECONDARY WARM FRONT...WHICH LIES IN THE AREA OF GREATER SFC INSOLATION SOUTH OF I-80. THE 12Z ILX SOUNDING INDICATES AT LEAST SOME VEERING OF WINDS THROUGH THE LOWER LEVELS WHICH WOULD HELP ADD SOME ROTATIONAL ASPECT TO STORMS...WHICH IN TURN COULD ADD A LARGE HAIL OR TORNADIC POTENTIAL TO THE STRONG WIND THREAT. ON TOP OF ALL OF THIS WILL BE A HEAVY RAINFALL POTENTIAL. THE 12Z KDVN SOUNDING INDICATES PWAT OF 1.4 INCHES...SO DEEP LAYER MOISTURE IS ALREADY IN PLACE. THE VARIOUS MODEL FORECAST PWATS INDICATE THAT A CORRIDOR OF EXTREME DEEP LAYER MOISTURE POOLING IN A CORRIDOR FROM SWRN WISCONSIN TO NERN KANSAS. WITH TIME AND PROGRESSION OF THE PATTERN...EXPECT THAT PWATS WILL ONLY INCREASE OVER THE LOCAL AREA THROUGH THE NEXT 36HRS. THE KDVN PWAT CLIMATOLOGY INDICATES THAT FOR OCTOBER...2 STANDARD DEVIATIONS FROM NORMAL IS 1.6 INCHES AND THE 99TH PERCENTILE PWAT IS 1.9 INCHES. THE LATEST MODEL RUNS SHOW PWAT INCREASING TO IN EXCESS OF 1.5 INCHES IN THE ENVIRONMENT AHEAD OF THE APPROACHING COLD FRONT. SO...FOR THE SEVERE WEATHER THREAT...TIMING AND COVERAGE ARE THE BIG QUESTIONS. ANTICIPATE THAT THE GREATEST SEVERE WEATHER THREAT WILL BE WITH THE COLD FRONT DUE TO THE GREATER SFC FORCING WHICH WILL LINE UP WITH THE FAVORABLE UPPER DYNAMICS WITH THE UPPER TROUGH. HOWEVER...THERE WILL STILL BE A MORE ISOLATED SEVERE WEATHER THREAT ACROSS THE LOCAL AREA SIMPLY DUE TO THE UNSEASONABLY STRONG LOWER LEVEL THERMODYNAMICS AND EXTREME DEEP LAYER MOISTURE. ALONG WITH THE SEVERE WEATHER THREAT...HEAVY RAINFALL AND LOCALIZED FLOODING WILL BE A CONCERN. THE PRIMARY LOCATION FOR POSSIBLE FLOODING WILL BE ALONG THE SECONDARY WARM FRONT AS RADAR TRENDS INDICATE THAT THE BOUNDARY ITSELF IS QUASISTATIONARY WHILE INDIVIDUAL CELLS TRACK TO THE EAST. THE CURRENT CONVECTIVE ACTIVITY ALONG THIS BOUNDARY IS CURRENTLY OVER NRN INDIANA...BUT RADAR SHOWS A FINE-LINE WEST INTO NERN IL. IF CONVECTION FILLS IN ALONG THE BOUNDARY AND IT REMAINS QUASISTATIONARY OR AT LEAST SLOWLY PROGRESSIVE...LOCALIZED FLOODING WILL BECOME AN INCREASING CONCERN. FOR TIMING OF THE PROGRESSION OF THE COLD FRONT...THE VARIOUS MODELS HAVE CONVERGED INTO GOOD AGREEMENT ON THE PROGRESSION...CROSSING THE RIVER INTO NWRN IL BY ARND 12Z SATURDAY AND STEADILY PROGRESSING EWD TO NRN INDIANA BY LATE AFTERNOON OR EARLY EVENING. THE THUNDERSTORM THREAT SHOULD BE CONFINED TO A ZONE ALONG AND AHEAD OF THE FRONT. FOLLOWING THE FRONTAL PASSAGE...CONDITIONS SHOULD QUICKLY IMPROVE...FOR A TIME...WITH TEMPERATURES DROPPING OFF QUICKLY. TEMPERATURES WILL DROP OFF FROM HIGHS IN THE LOW TO MIDDLE 80S TODAY AND SATURDAY TO LOWS IN THE UPPER 40S TO MIDDLE 50S SUNDAY MORNING AND LOWS IN THE MIDDLE 40S BY MONDAY MORNING. HIGHS FOR SUNDAY AND MONDAY SHOULD BE IN THE LOWER TO MIDDLE 60S. THERE WILL STILL BE SOME CHANCE FOR SOME PCPN SUNDAY AND MONDAY AS THE CENTER OF THE UPPER LOW TRACKS RIGHT OVER NRN IL/IN...BUT ANY PCPN SHOULD GENERALLY BE SCT SHOWERS AND PCPN AMOUNTS GENERALLY LIGHT. FOR THE EXTENDED FORECAST PERIOD...FROM TUESDAY THROUGH FRIDAY...EXPECT A PERIOD OF SLOWLY MODERATING TEMPERATURES WITH LITTLE TO NO CHANCE OF PCPN. FOLLOWING THE PASSAGE OF THE UPPER LOW...A BUILDING UPPER LEVEL RIDGE WILL SLOWLY MOVE OUT OVER THE PLAINS AND MISSISSIPPI VALLEY AS ANOTHER DEEP UPPER LOW DROPS DOWN THE WEST COAST INTO THE DESERT SOUTHWEST. THE AMPLIFYING...BUT SLOWLY PROGRESSIVE PATTERN ALOFT WILL KEEP CONDITIONS DRY WITH ABOVE NORMAL TEMPS OVER THE LOCAL WITH HIGHS IN THE LOWER TO MIDDLE 70S AND LOWS IN THE UPPER 40S TO MIDDLE 50S. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 03Z... * LOWERING VISIBILITY AND CIGS INTO IFR CATEGORY INTO OVERNIGHT. * NORTHEAST WINDS BECOMING EAST THEN SOUTHEAST TONIGHT WITH SPEEDS MOST OF TIME BELOW 10 KT. * SMALL CHANCE OF TSRA SAT MORNING GRADUALLY INCREASING INTO MID- AFTERNOON. * THUNDERSTORMS LIKELY 21Z-02Z SOME OF WHICH COULD BE STRONG. //DISCUSSION...UPDATED 00Z... COMPLEX AVIATION FORECAST AS STATIONARY BOUNDARY IS IN PLACE FROM JUST NORTH OF QUAD CITIES EASTWARD NEAR I-80. WITH TERMINALS BEING NORTH OF THIS...WIND FLOW OF NE TO E IS EXPECTED MUCH OF THIS EVE THOUGH SPEEDS SHOULD REMAIN MAINLY BELOW 10 KT. THIS LOCATION NORTH OF THE FRONT ALONG WITH ANOMALOUSLY HIGH LOW-LEVEL MOISTURE WILL SET THE STAGE FOR CONTINUING DECREASING VISIBILITY AND CIGS TONIGHT. THE LATEST SATELLITE IMAGERY AND OBSERVATIONS ARE INDICATING THE CIGS BECOMING MORE WIDESPREAD AND EXPECT THAT TAFS WILL HAVE TO ACCOUNT FOR THESE MORE IN TIME. EITHER WAY...IFR CONDITIONS ARE EXPECTED TO DEVELOP FROM NORTH TO SOUTH THIS EVE. THE BOUNDARY SHOULD MOVE GRADUALLY NORTH INTO SATURDAY MORNING ALLOWING FOR THE FOG AND STRATUS TO DIMINISH DURING THAT TIME. ATTENTION THEN TURNS TO THUNDER LIKELIHOOD BY EARLY AFTERNOON IN ROCKFORD AND MID AFTERNOON INTO EARLY EVE AT CHICAGO SITES. THIS WILL AHEAD OF A POTENT COLD FRONT WORKING EASTWARD. SOME OF THE STORMS WILL PROBABLY BE GUSTY...POSSIBLY WITH SEVERE GUSTS...AND THAT MOST FAVORED TIMING WILL BE AT THE LEADING EDGE OF THE STORMS. SOUTH SOUTHWEST WINDS WILL BE GUSTY AT TIMES AND THEN TURN WESTERLY BEHIND THE FRONT SATURDAY EVE. //ORD AND MDW CONFIDENCE...UPDATED 03Z... * HIGH CONFIDENCE IN STABLE/SLIGHTLY LOWERING TREND OF CIG...MEDIUM CONFIDENCE ON VISIBILITY. MEDIUM CONFIDENCE ON HOW LOW CIG AND VISIBILITY WILL FALL. * MEDIUM-HIGH CONFIDENCE IN WIND FORECAST. * MEDIUM CONFIDENCE ON TSRA TIMING OF 21Z-02Z. //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...VFR DURING THE DAY WITH MVFR CIGS AND CHC SHRA DURING THE NIGHT. MONDAY...CHC OF MVFR AND SLT CHC OF SHRA DURING THE MORNING. TUESDAY-THURSDAY...MAINLY VFR. MTF && .MARINE... 341 PM CDT A TROUGH OF LOW PRESSURE AND ASSOCIATED FRONTAL BOUNDARY ARE SITUATED ACROSS THE UPPER MISSISSIPPI VALLEY EAST ACROSS TO THE SOUTHERN GREAT LAKES REGION...WITH THESE FEATURES STEMMING FROM AN AREA OF LOW PRESSURE SITUATED OVER THE CENTRAL PLAINS. ITS THESE FEATURES THAT ARE PROVIDING...AND WILL CONTINUE TO PROVIDE DRASTICALLY VARYING CONDITIONS ACROSS THE ENTIRE LAKE. A LIGHTER WIND FIELD IS CURRENTLY PRESENT OVER THE SOUTHERN PORTIONS OF THE LAKE WHERE THE PRESSURE GRADIENT IS RELAXED...BUT WITH SPEEDS INCREASING TO 15 TO 25 KT FOR THE FAR NORTHERN PORTIONS OF THE LAKE. THIS BOUNDARY WILL LIFT BACK NORTH ACROSS THE LAKE TONIGHT INTO SATURDAY WHILE THIS LOW PRESSURE SYSTEM SLOWLY TRACKS NORTHEAST TOWARDS THE MISSISSIPPI VALLEY. AS THIS OCCURS...EXPECT A GRADUAL TRANSITION TO THE EAST SOUTHEAST WITH SPEEDS INCREASING ACROSS THE ENTIRE LAKE. EXPECT THE HIGHEST SPEEDS OF 30KT TO BE OBSERVED ACROSS THE NORTH...WITH THESE EASTERLY WINDS/SPEEDS LIKELY PERSISTING INTO EARLY SATURDAY NIGHT. EXPECT THIS LOW TO THEN CONTINUE NORTHEAST AND REACH THE CENTRAL GREAT LAKES LATE SATURDAY NIGHT INTO SUNDAY...AND THEN CONTINUE EAST TOWARDS THE EASTERN GREAT LAKES SUNDAY NIGHT INTO MONDAY. AS THIS OCCURS...EXPECT SPEEDS TO DIMINISH WHILE BECOMING MORE SOUTHERLY ON SUNDAY AND THEN WEST/NORTHWEST INTO MONDAY. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
  [top] Area Forecast Discussion National Weather Service Lincoln IL 851 PM CDT Fri Oct 4 2013 .DISCUSSION... ISSUED 850 PM CDT Fri Oct 4 2013 Updated the forecast for tonight to increase the PoPs early in southeast IL for the isolated showers and few rumbles of thunder. Also dropped the PoPs a bit in areas west of the IL River. Radar trends with the convection in Iowa and western Missouri, along with high res model solutions from the HRRR and RAP, indicate that the showers and t-storms may not impact west central IL until close to daybreak. Otherwise, the forecast low temperatures, sky cover and wind are all on track for the rest of tonight. Miller && .AVIATION... ISSUED 650 PM CDT Fri Oct 4 2013 Main aviation weather concerns for the next 24 hours will be the potential for MVFR, and at times IFR, ceilings and visibility early in the morning, and then the timing of the convection and associated cold front. Similar to the past few nights, warm and moist air in the lower atmosphere will eventually yield areas of light fog/mist and the potential for IFR ceilings after 09Z. Once again, a south wind of 6 to 10 knots should keep the fog from becoming thicker. Remnants of the convection that is currently ongoing in the Plains is expected in central IL during the late morning. There is the potential for scattered showers and t-storms to develop ahead of this convection toward daybreak. However, confidence is not very high with only one operational model - the GFS - indicating this potential. The big issue for Saturday will be the approaching cold front and t-storms that are expected with it. Model consensus is that convection is expected to develop/intensify between the IL River and I-55 from very late in the morning into early afternoon, with the frontal passage around 20-22Z. The instability is expected to be modest, but increasing unidirectional vertical wind shear could produce some fairly strong to severe wind gusts with the t-storms. Picking any particular TAF site where this may happen is difficult this far out, so will stick with a predominant TSRA group for now and make adjustments with future forecasts. Eastern IL may see scattered showers and t-storms from late morning into the afternoon. The best potential for widespread thunderstorms is expected late in the afternoon with the frontal passage after dark. Miller && .PREV DISCUSSION... ISSUED 300 PM CDT Fri Oct 4 2013 The current heat and humidity will be displaced by a chilly Canadian airmass after a strong cold front moves through on Saturday. Severe weather potential will increase as we head into Saturday afternoon, especially if sunshine is able to help destabilized the boundary layer for any portion of the day. A slight risk for severe storms has been outlined by SPC for nearly all of Illinois. The timing of the front remains in question, with a compromise used between the faster NAM/Canadian and the slower GFS/ECMWF. That basically allowed for some consistency with the going forecast. Dry air will be wrapping into the back side of the cold front, but as the occlusion process occurs, bands of moisture will trail the front and allow for a few post frontal showers to linger into Sunday and possibly even Monday. SHORT TERM...Tonight through Sunday night. A Pacific moisture connection will continue to feed into the warm sector across the nations heartland over the next 24-36 hours...as the warm front lingers in N Iowa and S Wisconsin. Localized pockets of energy will tap into that moisture to fuel isolated showers in our SE counties as well as our far NW counties into this evening. Most areas should remain dry this evening, and even overnight. We left a wide area of slight chance pops across the area after midnight, with chance PoPs in the far NW closer to the expected storm track. Tonight and early Saturday, low pressure in the western plains will lift north into eastern South Dakota before stalling during occlusion. It`s eastward progression will pick up speed as a kicker trough enters the northwest coast. The timing of the front will be key in where severe potential is maximized, mainly from the amount of sunshine for low level heating. There may be some isolated severe storms overnight west of our area as the nocturnal jet intensifies ahead of the cold front. The cold front is projected to reach the I-55 corridor by Noon or 1 pm, then slow down and reach the Indiana border mid- evening. Instability params and hodographs are pointing toward damaging winds as the main hazard in our area, with better directional shear and rotating storms farther north near the warm front and track of the low. Hail potential will increase closer to the cold front and moisture pooling and updraft strength intensify. Severe chances will linger into the evening east of I-57, but should become more isolated as the front slows down. We kept likely PoPs east of I-57 Sat eve, and near the Indiana border after midnight. Coverage of storms will likely diminish Sat night as will intensity. Some clearing behind the cold front will low temps drop into the 40s by Sunday morning west of I-55. The cold air will limit highs on Sunday to the upper 50s near GBG and mid 60s near LWV. Scattered rain will be possible across the east and north associated with cold pool-instability showers...as the upper trough lingers just west of IL. Sunday night will be coldest night of the next week, with lows in the low to mid 40s everywhere. LONG TERM...Monday through Friday. The upper vortex may still be over IL on Monday if the GFS and ECMWF verify, which would put showers across IL during the day. We left Mon dry for now, but at least sprinkles may be needed if the next couple of model runs show the slower progression. A warming trend will begin on Tue and continue through Friday. Highs should reach above normal into the mid 70s Thur/Fri. Dry conditions are expected to prevail all week, with comfortable humidity levels. The next chance of rain may hold off until the Sunday Oct 13. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
943 PM CDT Fri Oct 4 2013 .UPDATE... Issued at 931 PM CDT FRI OCT 4 2013 Weak elevated lift occurring behind the cold front across portions of northeast and north central Kansas has triggered a few isolated showers. Observations and latest runs of the HRRR suggest these benign showers to linger through the overnight period before clearing skies bring an end to the precipitation. && .SHORT TERM...(This Evening through Saturday) Issued at 318 PM CDT FRI OCT 4 2013 Latest surface analysis at 19Z had the cold front extending from east of Concordia through Salina and into northwest Oklahoma. Dew points and temperatures have dropped back into the 40s and 50s behind the front. Visible satellite loop shows cu field along the front which had developed since 18Z. Surface based CAPE is in the 2500 to 4000 J/kg range. 18Z TOP sounding still showed a Cap in place, but is expected to erode by 21Z. 0-6 km shear is forecast to be in the 30 to 40 kt range. Low level helicity is highest near the Nebraska border in far northeast Kansas. Across the rest of the area values are lower and low level winds from VAD and profilers should little turning with height in the low levels with the best low level shear in Nebraska. As the front continues to move through have adjusted where convective initiation is expected to occur which is from near Abilene through Marysville, so have lowered or eliminated chances of thunderstorms across north central Kansas. Shear and instability are favorable for severe storms late this afternoon and evening with damaging winds and hail the main hazards, but an isolated tornado cannot be ruled out. Initial cells forming along the front will become linear in nature as they move east across the cwa with bowing segments owning to the wind threat. Precipitation should come to an end by sunrise Saturday with skies clearing out during the morning hours. Cold advection tonight and Saturday will bring an abrupt drop in temperatures with lows in the 40s tonight and highs in the 50s to lower 60s Saturday. .LONG TERM...(Saturday Night through Friday) Issued at 318 PM CDT FRI OCT 4 2013 Upper low will progress eastward through the mid MO and MS valleys Sat night through Sunday night. As it does...the cyclonic circulation around it will likely clip the northern cwa with stratocu deck. However it remains a challenge this far out to determine how extensive the cloud cover and period of time the clouds will linger. Either way...decent mixing should persist through the night into Sunday morning...which along with any clouds should help to keep overnight lows up a bit. Will keep lows in the upper 30s to around 40 degrees for now...but if clouds are more extensive than current fcst...then lows may need to be increased slightly. Clouds on Sunday should be most extensive across the northeast corner in better proximity to exiting upper low and will keep highs in the upper 50s in that with low to mid 60s elsewhere with more sunshine. Upper level ridging will develop across the central plains as the first trough exits to the east and a second upper trough digs into the western coast. Will slowly but steadily increase high temps through the 70s next week while warming lows from the lower 40s Monday...to the middle and upper 50s by Thursday. Will include low chances for showers and thunderstorms west to east across the cwa Thursday night into Friday as the western trough begins to eject out into the plains. && .AVIATION...(For the 00Z TAFs through 00Z Saturday Evening) Issued at 650 PM CDT FRI OCT 4 2013 Line of thunderstorms will move through TOP and FOE terminals through 02Z. Winds may gust to 45 kts with the stronger cells. Behind the front expect winds to shift to the west with gust front then become southwest around 12 kts. After 03Z west to northwest winds of 12 mph will prevail along with VFR conditions. Winds will increase after 15Z to around 14 kts with gusts up to 25 kts possible. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Bowen SHORT TERM...53 LONG TERM...63 AVIATION...53
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1039 PM EDT FRI OCT 4 2013 .SYNOPSIS... WEAK HIGH PRESSURE WILL REMAIN OVER NEW ENGLAND THROUGH SATURDAY WHILE A STATIONARY FRONT REMAINS OVER SOUTHERN NEW ENGLAND AND EASTERN NEW YORK STATE. LOW PRESSURE WILL PULL A WARM FRONT NORTH ACROSS THE AREA LATE SUNDAY OR SUNDAY NIGHT...WITH A TRAILING COLD FRONT TO CROSS THE REGION TUESDAY. SOME OF THE MOISTURE FROM THE REMAINS OF TROPICAL STORM KAREN MAY MOVE UP ALONG THIS FRONT. && .NEAR TERM /THROUGH SATURDAY/... UPDATE...A FEW CHANGES TO THE CURRENT FORECAST BASED ON LATEST GUIDANCE/TRENDS. HAVE SHARPENED THE TEMP GRADIENT ACROSS THE CWFA. BREAKS IN OR THIN CLOUDS ACROSS THE FAR NE WILL ALLOW TEMPS TO APPROACH THE UPPER 30S TONIGHT...WHILE THICKENING CLOUD COVER WILL KEEP THINGS MILDER ACROSS THE S. EXPECT A MOSTLY DRY NIGHT...SO HAVE TRENDED POP DOWN FROM PREVIOUS FORECAST. A FEW ISOLD SHRA MAY BE POSSIBLE ACROSS SRN ZONES...CLOSER TO THE WARM FNT. PREVIOUS DISCUSSION...CLOUD SHIELD HAS FINALLY REACHED EASTERN PORTIONS OF THE FORECAST AREA...DESPITE DRY AIR ASSOCIATED WITH SURFACE HIGH PRESSURE OVER NORTHERN NEW ENGLAND. AN AREA OF SHOWERS HAS JUST EXITED THE NH SEACOAST...MUCH IN LINE WITH THE TIMING OF THE LATEST HRRR MODEL. MORE SHOWERS CONTINUE TO DEVELOP OVER QUEBEC PROVINCE AND SLIDE TO THE SOUTH AND EAST. THERE IS STILL A GOOD AMOUNT OF DRY AIR IN THE SOUNDING...HOWEVER A FEW OF THESE SHOWERS MAY SURVIVE THE TRIP THROUGH THE REGION. PLACED A SMALL AREA OF PATCHY LATE NIGHT FOG INTO THE CT RIVER VALLEY TONIGHT. DESPITE CLOUD COVER...SOME FOG MAY DEVELOP IN THE LEBANON AND ADJACENT VALLEY AREAS. && .SHORT TERM /SATURDAY NIGHT/... THE BATTLE BETWEEN THE RIDGE TO OUR NORTH AND EAST...AND A STATIONARY FRONT TO OUR SOUTH AND WEST WILL CONTINUE ON SATURDAY AND SATURDAY NIGHT. BY LATE SATURDAY NIGHT...THIS FRONT ADVANCES TOWARDS NORTHERN NEW ENGLAND AS A WARM FRONT. LIMITED MOISTURE MOVING INTO THE RIDGE UNDER A WARM AIR ADVECTION PATTERN MAY BRING A FEW LIGHT SHOWERS TO THE REGION. THE PROBABILITY OF PRECIPITATION WILL INCREASE LATE SATURDAY NIGHT AS THE FRONT APPROACHES. USED A BLEND OF MET/MAV MOS FOR TEMPS THIS PERIOD. && .LONG TERM /SUNDAY THROUGH FRIDAY/... A DIRTY UPPER RIDGE AXIS WILL EXTEND ACROSS NEW ENGLAND BUT A SHORT WAVE MOVES THROUGH ON SUNDAY AS A VERY MOIST ONSHORE SSELY FLOW DEVELOPS ALLOWING OVERRUNNING RAINS TO DEVELOP FROM S-N DURING THE DAY SUNDAY AND CONTINUE SUNDAY NIGHT INTO MON NIGHT AND PSBLY TUE. OVERNIGHT LOWS WILL REMAIN MILD BUT DAYTIME HIGHS WILL REMAIN COOL DUE TO THE ONSHORE FLOW EVEN THO H85 TEMPS WILL BE +12 TO +14C. THE MOISTURE THAT WILL BE ASSOCIATED FROM THE REMNANTS OF KAREN WILL ALSO GET ENTRAINED EARLY NEXT WEEK INTO THE SOUTHERLY FLOW ALOFT SO SOME HEAVY RAINS EXPECTED. BY WED AND THU THE GT LAKES UPR LOW DRIFTS EWD OVER NEW ENGL WITH A COOL CYCLONIC FLOW ALOFT SO A FEW INSTBLTY MAINLY AFTN SHWRS CAN`T BE RULED OUT EACH DAY BUT MAINLY IN THE MTNS. TEMPS TO REMAIN COOL THRU THE END OF THE WEEK DUE TO THE CYCLONIC UPR LOW OVER THE REGION. USED A BLEND OF THE EURO/MAV/MET/MEX GUID FOR THIS PCKG. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM...CHALLENGING FORECAST FOR TONIGHT IN TERMS OF CLOUD COVER AND POSSIBLE FOG. PLAN ON KEEPING ANY FOG LIMITED TO THE CT RIVER VALLEY...AND ONLY BRIEFLY FOR LATE TONIGHT. LONG TERM...SUN THRU LATE MON MVFR TO IFR CONDS EXPECTED IN RN/SHWRS/PATCHY DRZL. AREAS OF FOG ALG THE COAST WILL DEVELOP SUN NIGHT INTO MON REDUCING CONDS TO LIFR AT KPWM/KPSM/KRKD. IPVG CONDS EXPECTED TO MOSTLY VFR BY MIDWEEK. && .MARINE... SHORT TERM...WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. LONG TERM...WINDS AND SEAS WILL INCREASE BUT SHOULD REMAIN JUST BELOW SCA CRITERIA THROUGH MIDWEEK. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$ NEAR TERM...LEGRO
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1003 PM CDT Fri Oct 4 2013 .UPDATE: Issued at 950 PM CDT Fri Oct 4 2013 Inherited forecast still looks on track...so made no major changes. Warm advection SHRAS have moved out of SW IL. SHRA/TSTMS along and ahead of the front across ern KS/wrn MO timed to reach the wrn CWA around 9-10Z...if it holds together. Several solutions have moisture convergence along the front weakening significantly overnight across nthrn MO. Going fcst reflects the assumption that precip in one form or another will reach our CWA prior to daybreak. Besides massaging other grids to reflect ongoing trends...existing fcst looks good. 2% && .SHORT TERM: (Through Late Tonight) Issued at 330 PM CDT Fri Oct 4 2013 Diurnal heating of the unseasonably warm and moist air mass has resulted in weak instability across the region this afternoon. However with little impetus, attempts for convective development thus far across far southeast Missouri and southern Illinois have been short-lived. The HRRR continues to indicate potential for spot storms through sunset within the southern CWA so will continue with some slight chance pops until then. Otherwise attention for tonight turns to the strong storm system currently across the Plains region. Anticipating that a squall line will evolve ahead of the attendant cold front from Nebraska into Oklahoma this evening and this will move eastward as the whole system progresses, with a swath of precipitation also developing overnight in the wake of the front in response to frontogenetical forcing and large scale ascent as a short-wave rotates through the base of the progressive upper trof. The main question then is just how far eastward all of this precipitation will get before daybreak Saturday. The consensus of the model guidance is that it may be after 12z before entering the CWA. At this time I didn`t deviate dramatically from the previous forecast with the leading edge just making it into the western CWA, but reduced pops further east. Areas to the east of the main line will still be under the threat of spotty warm advection activity overnight. Glass .LONG TERM: (Saturday through Next Friday) Issued at 300 PM CDT Fri Oct 4 2013 By Saturday morning, surface cold front to be just west of St. Louis metro area. As the occluded surface low, over southeastern SD, associated with it slowly lifts out to the northeast, front to slowly slide through rest of forecast area. Expect activity that initially forms tonight to diminish by mid morning. Then trying to determine when and where activity will refire as atmosphere becomes more unstable by early afternoon is hard to pin down. With front extending from Quincy to just west of St. Louis to near Monett by 18z Saturday, best chances of storms refiring and some severe weather will be over southeast MO and southern IL. This matches well with the day 2 outlook with this area in a slight risk. Another forecast issue will be temperatures on Saturday. Will see a non-diurnal trend as high temps will be reached early in the day then either remain steady or fall during the afternoon hours. Showers and isolated thunderstorms will taper off Saturday evening before coming to an end. However, could see some scattered showers on Sunday, especially during the afternoon hours as wrap around clouds on back side of system moves through with an upper level shortwave. So have added low chance pops over northeast MO/west central IL with silent slight chance pops further south for now as well as increase cloud cover through this period. Lows Saturday night will be in the low 40s to low 50s with highs only rising into the mid 50s to mid 60s on Sunday. Sunday night could be our coldest night depending on how fast the clouds clear out. For now will err on side of caution and keep more clouds over the region with lows in the low to mid 40s. If clouds completely clear out and winds remain light, could see even cooler temps. Beyond that, surface ridge moves off to the east with a slow warming trend through the week. Temperatures to warm back up into the mid to upper 70s by Thursday. Byrd && .AVIATION: (For the 00z TAFs through 00z Saturday Evening) Issued at 632 PM CDT Fri Oct 4 2013 High pressure along the eastern seaboard combined with a deep surface low over northeast Nebraska and cold front extending south into eastern Kansas and then into west central Texas. Cold front from the west is expected to move eastward into east central Missouri by late Saturday morning. Scattered rainshowers and a few thunderstorms are expected along the cold front. Then post frontal rain can be expected behind the cold front through early Saturday evening hours. Specifics for KSTL: Southerly winds of 5 to 8 kts will increase to 10 kts from the southwest by mid Saturday morning. Cold front will move through STL area between 1700-1800 UTC on Saturday. Scattered showers and thunderstorms will move across the area from late Saturday morning through early afternoon. Low clouds around 015Kft and light rain..fog will continue through late afternoon hours. Przybylinski && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
740 PM CDT Fri Oct 4 2013 .MESOSCALE DISCUSSION... Issued at 726 PM CDT FRI OCT 4 2013 Last several hours of radar imagery have shown an interesting trend with a rapid initial upscale growth into a squall line, followed by a subsequent weakening. 18Z KTOP sounding showed the dry EML and high LFC combination that ultimately led to the rapid gusting out of the initial convection. Nevertheless, I believe that this weakening is short-lived. Despite having lost daytime heating, the gust front/cold front, now arcing from Omaha to Topeka to Emporia, is entering a very warm and substantially more moist airmass. Slow nocturnal cooling will actually aid in the low level buoyancy by offsetting the high LFC heights, and thus muting the effects of cold down drafts/evaporation. Additionally, the backing of the warm sector flow should enhance frontal convergence in the next 1-2 hours, with a developing low level jet further aiding in large scale ascent. Thus, it seems to reason that a temporary upswing in thunderstorms is likely as the gust front advances towards the I-35 corridor from Emporia through Kansas City. Deep layer shear vectors initially suggested that convective mode would be solely linear, but a recent analysis of RAP data overlayed against the surface front orientation captures enough cross angle to support more discrete development (supported by ICT radar imagery). Although small bowing segments would largely support wind damage, any discrete development and storm scale rotation could also support large hail and possible a tornado or two as 0-1km storm relative helicity is maximized between 01 and 03Z. Linear extrapolation of this activity places it across the Kansas City Metro between 8:30 and 10PM. Bookbinder && .UPDATE... Issued at 731 PM CDT FRI OCT 4 2013 Updated forecast to refine the evolution of precipitation tonight. Solid line of storms across central Kansas is no longer as solid as it was earlier today. Discreet bowing segments of the line keep trying to push out from the front, but then they fade as the gust front from the storm pushes out ahead, thus forcing the storm to reform back along the advancing front. So while the storms, and the timing for these storms, remains relatively unchanged the widespread severe weather expected will likely be more discrete but could still contain damaging winds. Otherwise...trimmed down POPs in the post frontal environment as latest model runs have backed off on the rain behind the front, which looks reasonable as the parent low driving this activity looks to be occluding to our north, thus possibly limiting the elevated frontogenic forcing lagging behind the front. && .SHORT TERM...(This Evening through Saturday Afternoon) Issued at 339 PM CDT FRI OCT 4 2013 Focus for todays forecast is squarely on the remainder of the afternoon and overnight hours as a cold front and associated thunderstorms sweep through. A large upper level trough is exiting the Rocky Mountains this afternoon. As this occurs copious amounts of warm air and moisture for this time of year are being advected north ahead of the cold front, which is associated with this trough and currently moving east through central Kansas. Early afternoon analysis shows the elevated mix layer that advected in aloft late this morning, putting the kibosh on this mornings convection, has begun to erode. Storms currently forming in extreme northeast Kansas --well in advance of the front-- will likely help keep the effective frontal boundary across northern Missouri in northern Missouri through the afternoon and evening hours as the storms quickly transit the front and reinforce the cold air across the Iowa border. Looking at visible satellite imagery, a thin line of clouds have begun to erupt along the cold front in central Kansas, and it is this line of developing storms which is expected to grow through the remainder of the afternoon bringing potential severe weather to eastern Kansas and western Missouri this evening. For this afternoon...storms bubbling up across extreme northeast Kansas and sweeping into northwest Missouri may be strong at times as elevated instability values of 3000 to 3500 J/KG pushes in above the cap. However, despite the abundant instability these storms are not based at the surface at this time as the effective warm front put down early this morning in northern Missouri is only slowly retreating north towards a secondary warm front along I-80 in Iowa. This should limit mid to late afternoon severe threats as the cloud cover and rain cooled air form the storms slow the retreat even more. As a result, still expect the main show for tonight to develop from the fine line of clouds forming along the front in central Kansas. Models persist in displaying good agreement on this evenings expected activity. Current forecast has the front entering our section of northeastern and east central Kansas between 6PM and 7PM. This will be late enough in the day for instability to have trended down, but there should be more than enough available energy still there to fuel strong to severe storms as they move into Missouri this evening. 0-6KM Shear vectors will be running near parallel to the front as it moves in this evening across areas of west central Missouri, but those areas in far northwest Missouri --near the Iowa border-- will still have slightly more backed winds at the surface, which might enhance the threat for supercell thunderstorms north of St Joseph. As the front pushes in this evening the upper level low within the trough will only slowly shift northeast, and is expected to allow the front to occlude later tonight which will likely force the severe threat south along the cold front in southeast Kansas and Oklahoma, thus limiting the time period and location for strong to severe thunderstorms to areas near and west of I-35. Timing for the strongest storms is expected between 7PM and 10PM. Primary threats are thought to be from large hail and damaging straighting winds, though torrential rain and abundant lightning will also be present. With all of the fall outdoor activities this evening folks are encouraged to pay close attention to the weather. After the main line of storms sweep through tonight, stratiform rain with embedded thunder will remain likely well through the overnight hours behind the front as frontogenic forcing from the cold air sweeping in and goes to work on the moisture wrapping around the low. Some lingering activity from the storms could still effect areas from central to northeast Missouri through noon Saturday. Additionally, behind the cold front cold air will spread across the region with gusty west to northwest winds dominating the day. This will likely leave temperatures Saturday struggling to reach 60 degrees. .LONG TERM...(Saturday Evening through Friday) Issued at 339 PM CDT FRI OCT 4 2013 A rather quiet extended forecast period expected behind a large upper level trough currently moving into the Plains. Once this system exits the local region, much cooler air will linger across the area and only allow highs to climb into the upper 50s and low 60s by Sunday afternoon. Current models have slowed this upper level low a bit, allowing for a few scattered rain showers to be possible on the backside of this system. This precipitation will primarily be across the northern portion of MO, and will be dependent on the final speed and placement of the upper low as it begins to move out of the mid-MO region. Once this system moves out of the region, northwest flow will briefly return as shortwave ridging builds into the the central US. Southwest flow will develop across the Plains as a deepening trough across the western Cascades aides in building the ridge eastward. As a result, the cooler early week temperatures will undergo a gradual warming trend with highs in the 70s by the end of the week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday Evening) Issued at 652 PM CDT FRI OCT 4 2013 Main focus for the 00Z TAFs is the line of storms advancing across eastern Kansas this evening. Current timing for storms would have them reach KSTJ near 01Z with the Kansas City terminals around 02Z. Given the limited width of the current line of storms, expectations are that they will only impact the terminals for a few hours this evening...though they will likely have strong and gusty winds which could be widely variable in direction near the storms. Questions still exists with how low clouds will be behind the front, so have left in a combination of MVFR to VFR ceilings for the morning hours of Saturday. Gusty winds will spread in behind the front Saturday, with gusty west winds onsetting around noon Saturday. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ MESOSCALE...Bookbinder UPDATE...Cutter SHORT TERM...Cutter LONG TERM...PMM AVIATION...Cutter
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
726 PM CDT FRI OCT 4 2013 .MESOSCALE DISCUSSION... Issued at 726 PM CDT FRI OCT 4 2013 Last several hours of radar imagery have shown an interesting trend with a rapid initial upscale growth into a squall line, followed by a subsequent weakening. 18Z KTOP sounding showed the dry EML and high LFC combination that ultimately led to the rapid gusting out of the initial convection. Nevertheless, I believe that this weakening is short-lived. Despite having lost daytime heating, the gust front/cold front, now arcing from Omaha to Topeka to Emporia, is entering a very warm and substantially more moist airmass. Slow nocturnal cooling will actually aid in the low level buoyancy by offsetting the high LFC heights, and thus muting the effects of cold down drafts/evaporation. Additionally, the backing of the warm sector flow should enhance frontal convergence in the next 1-2 hours, with a developing low level jet further aiding in large scale ascent. Thus, it seems to reason that a temporary upswing in thunderstorms is likely as the gust front advances towards the I-35 corridor from Emporia through Kansas City. Deep layer shear vectors initially suggested that convective mode would be solely linear, but a recent analysis of RAP data overlayed against the surface front orientation captures enough cross angle to support more discrete development (supported by ICT radar imagery). Although small bowing segments would largely support wind damage, any discrete development and storm scale rotation could also support large hail and possible a tornado or two as 0-1km storm relative helicity is maximized between 01 and 03Z. Linear extrapolation of this activity places it across the Kansas City Metro between 8:30 and 10PM. Bookbinder .SHORT TERM...(This Evening through Saturday Afternoon) Issued at 339 PM CDT FRI OCT 4 2013 Focus for todays forecast is squarely on the remainder of the afternoon and overnight hours as a cold front and associated thunderstorms sweep through. A large upper level trough is exiting the Rocky Mountains this afternoon. As this occurs copious amounts of warm air and moisture for this time of year are being advected north ahead of the cold front, which is associated with this trough and currently moving east through central Kansas. Early afternoon analysis shows the elevated mix layer that advected in aloft late this morning, putting the kibosh on this mornings convection, has begun to erode. Storms currently forming in extreme northeast Kansas --well in advance of the front-- will likely help keep the effective frontal boundary across northern Missouri in northern Missouri through the afternoon and evening hours as the storms quickly transit the front and reinforce the cold air across the Iowa border. Looking at visible satellite imagery, a thin line of clouds have begun to erupt along the cold front in central Kansas, and it is this line of developing storms which is expected to grow through the remainder of the afternoon bringing potential severe weather to eastern Kansas and western Missouri this evening. For this afternoon...storms bubbling up across extreme northeast Kansas and sweeping into northwest Missouri may be strong at times as elevated instability values of 3000 to 3500 J/KG pushes in above the cap. However, despite the abundant instability these storms are not based at the surface at this time as the effective warm front put down early this morning in northern Missouri is only slowly retreating north towards a secondary warm front along I-80 in Iowa. This should limit mid to late afternoon severe threats as the cloud cover and rain cooled air form the storms slow the retreat even more. As a result, still expect the main show for tonight to develop from the fine line of clouds forming along the front in central Kansas. Models persist in displaying good agreement on this evenings expected activity. Current forecast has the front entering our section of northeastern and east central Kansas between 6PM and 7PM. This will be late enough in the day for instability to have trended down, but there should be more than enough available energy still there to fuel strong to severe storms as they move into Missouri this evening. 0-6KM Shear vectors will be running near parallel to the front as it moves in this evening across areas of west central Missouri, but those areas in far northwest Missouri --near the Iowa border-- will still have slightly more backed winds at the surface, which might enhance the threat for supercell thunderstorms north of St Joseph. As the front pushes in this evening the upper level low within the trough will only slowly shift northeast, and is expected to allow the front to occlude later tonight which will likely force the severe threat south along the cold front in southeast Kansas and Oklahoma, thus limiting the time period and location for strong to severe thunderstorms to areas near and west of I-35. Timing for the strongest storms is expected between 7PM and 10PM. Primary threats are thought to be from large hail and damaging straighting winds, though torrential rain and abundant lightning will also be present. With all of the fall outdoor activities this evening folks are encouraged to pay close attention to the weather. After the main line of storms sweep through tonight, stratiform rain with embedded thunder will remain likely well through the overnight hours behind the front as frontogenic forcing from the cold air sweeping in and goes to work on the moisture wrapping around the low. Some lingering activity from the storms could still effect areas from central to northeast Missouri through noon Saturday. Additionally, behind the cold front cold air will spread across the region with gusty west to northwest winds dominating the day. This will likely leave temperatures Saturday struggling to reach 60 degrees. .LONG TERM...(Saturday Evening through Friday) Issued at 339 PM CDT FRI OCT 4 2013 A rather quiet extended forecast period expected behind a large upper level trough currently moving into the Plains. Once this system exits the local region, much cooler air will linger across the area and only allow highs to climb into the upper 50s and low 60s by Sunday afternoon. Current models have slowed this upper level low a bit, allowing for a few scattered rain showers to be possible on the backside of this system. This precipitation will primarily be across the northern portion of MO, and will be dependent on the final speed and placement of the upper low as it begins to move out of the mid-MO region. Once this system moves out of the region, northwest flow will briefly return as shortwave ridging builds into the the central US. Southwest flow will develop across the Plains as a deepening trough across the western Cascades aides in building the ridge eastward. As a result, the cooler early week temperatures will undergo a gradual warming trend with highs in the 70s by the end of the week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday Evening) Issued at 652 PM CDT FRI OCT 4 2013 Main focus for the 00Z TAFs is the line of storms advancing across eastern Kansas this evening. Current timing for storms would have them reach KSTJ near 01Z with the Kansas City terminals around 02Z. Given the limited width of the current line of storms, expectations are that they will only impact the terminals for a few hours this evening...though they will likely have strong and gusty winds which could be widely variable in direction near the storms. Questions still exists with how low clouds will be behind the front, so have left in a combination of MVFR to VFR ceilings for the morning hours of Saturday. Gusty winds will spread in behind the front Saturday, with gusty west winds onsetting around noon Saturday. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. && $$ MESOSCALE...Bookbinder SHORT TERM...Cutter LONG TERM...PMM AVIATION...Cutter
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
702 PM CDT Fri Oct 4 2013 .SHORT TERM: (Through Late Tonight) Issued at 330 PM CDT Fri Oct 4 2013 Diurnal heating of the unseasonably warm and moist air mass has resulted in weak instability across the region this afternoon. However with little impetus, attempts for convective development thus far across far southeast Missouri and southern Illinois have been short-lived. The HRRR continues to indicate potential for spot storms through sunset within the southern CWA so will continue with some slight chance pops until then. Otherwise attention for tonight turns to the strong storm system currently across the Plains region. Anticipating that a squall line will evolve ahead of the attendant cold front from Nebraska into Oklahoma this evening and this will move eastward as the whole system progresses, with a swath of precipitation also developing overnight in the wake of the front in response to frontogenetical forcing and large scale ascent as a short-wave rotates through the base of the progressive upper trof. The main question then is just how far eastward all of this precipitation will get before daybreak Saturday. The consensus of the model guidance is that it may be after 12z before entering the CWA. At this time I didn`t deviate dramatically from the previous forecast with the leading edge just making it into the western CWA, but reduced pops further east. Areas to the east of the main line will still be under the threat of spotty warm advection activity overnight. Glass .LONG TERM: (Saturday through Next Friday) Issued at 300 PM CDT Fri Oct 4 2013 By Saturday morning, surface cold front to be just west of St. Louis metro area. As the occluded surface low, over southeastern SD, associated with it slowly lifts out to the northeast, front to slowly slide through rest of forecast area. Expect activity that initially forms tonight to diminish by mid morning. Then trying to determine when and where activity will refire as atmosphere becomes more unstable by early afternoon is hard to pin down. With front extending from Quincy to just west of St. Louis to near Monett by 18z Saturday, best chances of storms refiring and some severe weather will be over southeast MO and southern IL. This matches well with the day 2 outlook with this area in a slight risk. Another forecast issue will be temperatures on Saturday. Will see a non-diurnal trend as high temps will be reached early in the day then either remain steady or fall during the afternoon hours. Showers and isolated thunderstorms will taper off Saturday evening before coming to an end. However, could see some scattered showers on Sunday, especially during the afternoon hours as wrap around clouds on back side of system moves through with an upper level shortwave. So have added low chance pops over northeast MO/west central IL with silent slight chance pops further south for now as well as increase cloud cover through this period. Lows Saturday night will be in the low 40s to low 50s with highs only rising into the mid 50s to mid 60s on Sunday. Sunday night could be our coldest night depending on how fast the clouds clear out. For now will err on side of caution and keep more clouds over the region with lows in the low to mid 40s. If clouds completely clear out and winds remain light, could see even cooler temps. Beyond that, surface ridge moves off to the east with a slow warming trend through the week. Temperatures to warm back up into the mid to upper 70s by Thursday. Byrd && .AVIATION: (For the 00z TAFs through 00z Saturday Evening) Issued at 632 PM CDT Fri Oct 4 2013 High pressure along the eastern seaboard combined with a deep surface low over northeast Nebraska and cold front extending south into eastern Kansas and then into west central Texas. Cold front from the west is expected to move eastward into east central Missouri by late Saturday morning. Scattered rainshowers and a few thunderstorms are expected along the cold front. Then post frontal rain can be expected behind the cold front through early Saturday evening hours. Specifics for KSTL: Southerly winds of 5 to 8 kts will increase to 10 kts from the southwest by mid Saturday morning. Cold front will move through STL area between 1700-1800 UTC on Saturday. Scattered showers and thunderstorms will move across the area from late Saturday morning through early afternoon. Low clouds around 015Kft and light rain..fog will continue through late afternoon hours. Przybylinski && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
833 PM MDT FRI OCT 4 2013 .UPDATE... NEAR-BLIZZARD CONDITIONS ARE ONGOING IN SOUTHERN CARTER COUNTY PER RECENT SPOTTER REPORTS...AND RADAR TRENDS SUGGEST SNOW SHOULD KEEP FALLING IN THE DEFORMATION ZONE FOR SEVERAL MORE HOURS. WE DO HAVE SOME QUESTION ABOUT HOW LONG SNOW WILL CONTINUE AFTER 06 UTC...BUT FORECAST SOUNDINGS FROM THE RAP SHOW 30 KT WINDS IN THE WELL-MIXED NEAR-SURFACE LAYER CONTINUE THROUGH THE NIGHT. THUS...IF SNOW DOES CONTINUE PAST MIDNIGHT VISIBILITY RESTRICTIONS WILL ALSO CONTINUE. WE THUS CHOSE TO EXTEND THE WINTER STORM WARNING FOR CARTER COUNTY UNTIL 12 UTC. WE RECEIVED REPORTS OF A FOOT OF SNOW IN ALZADA NEAR 0045 UTC...SO WHEN ALL IS SAID AND DONE STORM TOTALS WILL PROBABLY BE IN THE 13 TO 16 INCH RANGE IN SOUTHERN CARTER COUNTY. ELSEWHERE...OBSERVATIONS SUGGEST CONDITIONS ARE IMPROVING LIKE THE 18 UTC GFS/NAM AND RECENT RAP RUNS SUGGESTED...SO WE CANCELLED ALL OF THE WINTER STORM WARNINGS SAVE FOR CARTER COUNTY. NO OTHER REAL CHANGES OF NOTE APPEAR WARRANTED TO THE OVERNIGHT FORECAST AT THIS TIME...WITH THE FIRST FREEZE OF THE FALL SEASON ACROSS MUCH OF THE PLAINS EXPECTED TONIGHT. SCHULTZ && .SHORT TERM...VALID FOR SAT AND SUN... UPPER LOW WAS SEEN ON WATER VAPOR SPINNING INTO W NE THIS AFTERNOON. STORM SYSTEM HAS BEEN A PROLIFIC SNOW PRODUCER WITH 1 TO 2 FEET OF SNOW IN THE MOUNTAINS AND FOOTHILLS AND OVER SHERIDAN COUNTY. MANY LOCATIONS REPORTED DOWNED TREES AND POWER LINES WITH SUBSEQUENT POWER OUTAGES. THE SNOW CONTINUED TO FALL OVER SOUTHERN BIG HORN AND SHERIDAN COUNTIES...AS WELL AS SE MT THIS AFTERNOON. WILL LEAVE THE WARNING IN PLACE UNTIL 06Z TONIGHT WHEN LIFT DRAMATICALLY DECREASES DUE TO WEAKENING FRONTOGENESIS AND THE TROWAL SHIFTING TO THE E. ACCUMULATIONS SHOULD BECOME LIGHTER WITH TIME AS THE LIFT WEAKENS OVER THE AREA. WILL KEEP THE NEAR RECORD LOW MENTIONED FOR KSHR WITH ALL THE SNOW ON THE GROUND. ONLY ISSUES THAT MIGHT PREVENT RECORD FROM BEING REACHED WOULD BE CLOUD COVER AND WINDS STAYING UP. LOWERED TONIGHT/S MINS IN A FEW AREAS DUE TO THE SNOW COVER. FOG SHOULD NOT BE AN ISSUE AS DEWPOINTS WERE EXPECTED TO FALL OVERNIGHT. UPPER RIDGING AND DRY WEATHER WILL BUILD OVER THE AREA SAT THROUGH SUN NIGHT. SOME GAP FLOW CONDITIONS WILL SET UP FOR THE KLVM...BIG TIMBER AND HARLOWTON AREAS BUT PATTERN DID NOT SUPPORT OVERLY STRONG WINDS. MIXING BETWEEN 850 AND 700 MB WILL SUPPORT TEMPERATURES IN THE 50S ON SAT...BUT SOME READINGS WILL BE TEMPERED BY THE SNOW COVER. WARMER AIRMASS ON SUN WILL PUSH TEMPERATURES INTO THE 60S WITH A FEW 70S POSSIBLE. ARTHUR .LONG TERM...VALID FOR MON...TUE...WED...THU...FRI... A RIDGE OF HIGH PRESSURE WILL BRING DRY AND MILD CONDITIONS OVER THE AREA MONDAY. THIS RIDGE WILL SHIFT QUICKLY EASTWARD DURING THE DAY AS A LONG WAVE TROUGH OF LOW PRESSURE DEEPENS ALONG THE WEST COAST. FLOW WILL BEGIN BACKING TO THE SOUTHWEST WITH DIFFLUENT FLOW INCREASING ACROSS SC/SE MT. PIECES OF VORTICITY WILL BE EJECTING OUT AHEAD OF THE MAIN TROUGH AND THIS WILL BRING THE CHANCE OF A FEW RAIN SHOWERS TO OUR WESTERN ZONES TUESDAY AFTERNOON AND NIGHT WITH SNOW SHOWERS OVER THE MOUNTAINS. PRECIPITATION CHANCES WILL INCREASE WEDNESDAY THROUGH THURSDAY AS THE UPPER TROUGH MOVES INTO THE ROCKIES. GFS/ECMWF ARE CONSISTENT IN SHOWING THE DEVELOPMENT OF A CLOSED UPPER LOW OVER SOUTHERN NEVADA ON THURSDAY. THE LOW IS PROGGED TO LIFT NORTHEAST INTO SOUTHEASTERN WYOMING THURSDAY NIGHT. MODELS INDICATING THAT THIS LOW WILL BRING A POTENTIAL FOR ANOTHER STRONG FALL STORM TO IMPACT THE AREA. GFS IS THE STRONGEST OF THE TWO MODELS AND INDICATES THE CLOSED 500 MB LOW WILL MOVE INTO EXTREME SOUTHEAST MONTANA ON FRIDAY WITH THE 700 AND 850 MB LOWS STACKED UNDERNEATH IT. THIS WOULD CAUSE THE STORM SYSTEM TO MOVE SLOWER AND THUS BRING A LONGER PERIOD OF STRONG UPSLOPE FLOW TO MUCH OF THE FORECAST AREA. HAVE RAISED POPS THURSDAY NIGHT AND FRIDAY. TEMPERATURES STARTING OUT WELL ABOVE NORMAL FOR MONDAY WITH HIGHS RUNNING 15 TO 20 DEGREES ABOVE NORMAL. UPPER TROUGH MOVING IN ON TUESDAY WILL BRING FALLING HEIGHTS WHICH WILL ALLOW FOR TEMPERATURES FALLING TO THE LOWER 60S. WEDNESDAY THROUGH FRIDAY WILL SEE NEAR SEASONAL TEMPERATURES. RICHMOND && .AVIATION... VERY HAZARDOUS WEATHER WILL CONTINUE THROUGH ABOUT 09Z OVER THE SE CORNER OF MONTANA AND THE NEARBY AREAS INTO NE WYOMING. OTHERWISE...CONDITIONS WILL CONTINUE TO IMPROVE OVERNIGHT ACROSS THE REST OF THE FORECAST AREA. VFR IS EXPECTED TO PREVAIL AT ALL FORECAST TERMINALS...ALTHOUGH MOUNTAIN PEAKS MAY REMAIN OBSCURED UNTIL 12Z. BT && .PRELIMINARY POINT TEMP/POPS... SAT SUN MON TUE WED THU FRI ----------------------------------------------------------- BIL 028/056 042/069 043/070 043/062 039/057 037/053 040/052 00/N 00/N 00/U 02/W 22/W 23/W 33/W LVM 023/054 038/066 041/068 039/061 036/053 033/049 034/050 00/N 00/N 00/N 02/W 22/W 23/W 33/W HDN 027/058 038/070 040/070 041/065 039/059 038/054 040/053 10/U 00/U 00/U 01/B 22/W 22/W 33/W MLS 029/057 037/070 042/068 043/067 043/061 038/057 042/057 10/U 00/U 00/U 01/B 22/W 22/W 34/W 4BQ 026/050 033/065 038/066 040/064 039/059 036/055 038/054 51/U 00/U 00/U 01/B 12/W 22/W 35/W BHK 025/049 031/066 040/063 040/065 041/060 036/055 039/054 30/U 00/U 00/U 01/B 11/B 22/W 36/W SHR 019/048 032/063 039/068 040/065 038/059 034/054 036/053 20/U 00/U 00/U 01/B 22/W 22/W 34/W && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...WINTER STORM WARNING IN EFFECT UNTIL 6 AM MDT SATURDAY FOR ZONE 37. WY...NONE. && $$ WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
525 PM MDT FRI OCT 4 2013 .AVIATION... 00Z TAF CYCLE VFR CIGS AND VIZ NEXT 24 HRS. WEATHER SYSTEM OVER NEBRASKA PANHANDLE MAINTAINING GUSTY SOUTHWEST FLOW ACROSS NM...WITH COLD FRONT FROM THE TX PANHANDLE SWEEPING SOUTH AND WEST TO A ROW TO DMN LINE. WIND SPEEDS DECREASING GRADUALLY AFTER 01Z...WITH COLD FRONT REACHING THE MEXICO BORDER BY 12Z SAT MORNING. WINDS SHIFTING NORTHERLY AS FRONT SLIDES BY. REDUCED WIND SPEEDS FOR SATURDAY AS WEATHER SYSTEM SHIFTS TO MISSOURI RIVER VALLEY IN SD...NORTHERLY FLOW ALOFT OVER NM WEAKENS IN TURN...AND DOME OF HIGH PRESSURE BUILDS OUT OF WESTERN COLORADO INTO NORTHERN NM BY 00Z SAT EVENING. SHY && .PREV DISCUSSION...315 PM MDT FRI OCT 4 2013... FRONT HAS BEEN HUNG UP JUST NORTH OF THE UNION COUNTY BORDER ALL DAY...ALTHOUGH THE LOW CLOUDS ASSOCIATED WITH IT LAST NIGHT HAVE DISSIPATED OVER SOUTHEAST AND EAST CENTRAL CO. RUC INDICATES THE BOUNDARY TO PLUNGE SWD WITHIN THE NEXT 3 HOURS. IT ALSO INDICATES A LITTLE MORE MOISTURE OVER PARTS OF THE NORTHEAST...AND RESULT HAS BEEN TO UPGRADE SKY COVER TO PARTLY CLOUDY RATHER THAN CLEAR. STILL MODELS NOT SUGGESTING A HUGE UPTICK IN DEW POINTS THERE OVERNIGHT. NORTHERLY WINDS ASSOCIATED WITH THE FRONT AS IT TRACKS THROUGH THE PLAINS TO BE GUSTY BUT NOT QUITE AS STRONG AS INDICATED 24 HOURS AGO. AS FOR FREEZE HIGHLIGHTS...STILL SOME MARGINAL TEMPERATURES FOR PORTIONS OF THE EAST CENTRAL AND RGV AS WELL AS THE SOUTH CENTRAL HIGHLANDS. AND SATURDAY NIGHT TEMPERATURE GUIDANCE IS STILL LEANING TOWARDS SOME WARMING. FORECAST BOUNDARY LAYER WINDS TONIGHT NORTHEAST OVER THE PLAINS BUT FOR SATURDAY NIGHT THE GFS FORECASTS A MORE WLY WIND FLOW IN THE LOWER LEVELS...AS OPPOSED TO THE NAM/S LIGHT AND VRBL TO WEAK NW WINDS. FORECAST SOUNDINGS INDICATE SOME STEEP INVERSIONS OFF THE DECK AT SELECTED POINTS SATURDAY NIGHT BUT OVERALL THE SOUNDINGS EXHIBIT A WARMING TREND. THINK THERE MAY BE SOME POINTS IN SHELTERED AREAS UNAFFECTED BY WIND THAT COULD REACH THE MAGIC 32 OR SLIGHTLY BELOW OUTSIDE OF OUR FORECAST POINTS TONIGHT...SO WENT AHEAD AND UPGRADED REMAINING EAST CENTRAL ZONES IN THE WATCH. ALSO ADDED THE SOUTH CENTRAL HIGHLANDS TO THE WARNING TONIGHT WITH FORECAST LOWS AGAIN HOVERING NEAR THE FREEZING MARK. BASED ON THE ABOVE MODEL DISCUSSION...HAVE HELD OFF ON ISSUING FURTHER FREEZE HIGHLIGHTS FOR SATURDAY NIGHT. WILL WAIT TO SEE WHAT THE GUIDANCE DOES AS WELL AS WHAT MINS TONIGHT DO. WINDS STILL TO TAPER OFF SATURDAY WITH A WARMING TREND SUNDAY THROUGH TUESDAY. MODELS CONTINUE TO FOCUS ON AN UPPER LOW DIGGING INTO THE SW US AROUND THE MID TO LATE WEEK PERIOD NEXT WEEK. WINDS LOOK TO INCREASE TUESDAY AND MORE SO WEDNESDAY WITH TEMPERATURES FALLING THURSDAY/FRIDAY. WE NOW HAVE SOME MEAGER POPS FOR THE NORTH AND WEST DURING THIS PERIOD...BUT MODELS NOT EXACTLY IN AGREEMENT HOW THIS WILL PLAY OUT. .FIRE WEATHER... CURRENT FIRE WEATHER HIGHLIGHTS ARE MARGINAL BUT WILL KEEP THEM RUNNING THROUGH EVENT EXPIRATION. TUCUMCARI IS SHOWING NEAR RED FLAG CONDITIONS WITH GUSTY WINDS AND TEEN HUMIDITY. THE UPPER LOW WHICH IS CURRENTLY OVER THE CENTRAL ROCKIES AND GREAT PLAINS WILL GRADUALLY SHIFT EASTWARD THE REST OF TODAY...TONIGHT INTO SATURDAY. THE SURFACE WIND FLOW WILL GENERALLY RELAX AS A RESULT ALTHOUGH A BACK DOOR COLD FRONT WILL PUSH ACROSS THE EASTERN PLAINS TONIGHT AND INCREASE WINDS FOR A TIME. A CHILLY NIGHT IS IN STORE WITH FREEZING TO NEAR FREEZING TEMPERATURES EXPECTED ACROSS THE MAJORITY OF THE FIRE WEATHER FORECAST AREA. A HARD FREEZE WILL BE FELT ACROSS THE NORTHERN AND WESTERN MOUNTAINS AND INCLUDE SOME LOWLAND SITES AS WELL. HIGH PRESSURE WILL BE IN CONTROL DURING THE WEEKEND. THE SURFACE WIND FLOW WILL BE MUCH MORE RELAXED ALTHOUGH LOOK FOR SOME NORTHERLY BREEZES ACROSS SOME WESTERN AND CENTRAL AREAS SATURDAY AFTERNOON. THE FLOW ALOFT WILL BE MUCH WEAKER SO MAINLY SURFACE DRIVEN. FAIRLY LIGHT WINDS FOR SUNDAY WITH JUST A FEW BREEZES ALONG INTERSTATE 25 BETWEEN LAS VEGAS TO RATON. MIXING HEIGHTS WILL BE ON THE LOWER SIDE THANKS TO POST COLD FRONTAL INVERSION EFFECTS. THUS VENTILATION RATES WILL BE LOWER. VENTILATION WILL BE THE POOREST ON SUNDAY. EXPECTING A STRONG LOW LEVEL RADIATION INVERSION TO DEVELOP SATURDAY NIGHT. THIS WILL BE ACCOMPANIED BY ADDITIONAL FREEZING TEMPERATURES WITHIN BASINS AND VALLEYS. HIGH TEMPERATURES WILL BE WELL BELOW NORMAL SATURDAY AND BE AROUND 5 TO 10 DEGREES BELOW NORMAL SUNDAY AFTERNOON. HUMIDITY VALUES WILL BE NEAR SEASONABLE LEVELS ON SATURDAY BUT LOWER ON SUNDAY WITH LOTS OF MINIMUM VALUES IN THE TEENS. A MID LEVEL DRY INTRUSION PLUS A WARM UP WILL BE THE CATALYST FOR LOWER HUMIDITY VALUES SUNDAY. WEATHER MODELS REMAIN PERSISTENT WITH DEPICTING RIDGING ON MONDAY AND THEN BREAKING DOWN OR SHIFTING EASTWARD ON TUESDAY. TEMPERATURES WOULD CONTINUE TO WARM WHILE THE UPPER FLOW TURNS MORE SOUTHWESTERLY ON TUESDAY. DRY CONDITIONS WOULD CONTINUE. VENTILATION RATES WILL REMAIN ON THE LOWER SIDE MONDAY ALTHOUGH IMPROVE IN A FEW AREAS COMPARED TO SUNDAY/S READINGS. TRANSPORT WINDS WILL INCREASE TUESDAY SO THE VENTILATION WILL IMPROVE SIGNIFICANTLY THEN. NEAR TO ABOVE NORMAL TEMPERATURES EXPECTED EARLY NEXT WEEK AND SURFACE HUMIDITY WILL REMAIN ON THE LOWER SIDE. CURRENTLY HAVE SOME LOCALIZED CRITICAL FIRE WEATHER GROWTH CONDITIONS DEPICTED WITHIN OUR GRIDDED FORECAST TUESDAY AFTERNOON ACROSS THE NORTHEAST SO WILL BE MONITORING THAT TREND. THE LATEST LONG RANGE MODELS CONTINUE TO SHOW A BREEZY TO WINDY PATTERN WEDNESDAY THROUGH FRIDAY AS ANOTHER PACIFIC TROUGH CROSSES OVER THE INTERMOUNTAIN WEST. IT STILL APPEARS TO BE A DRY TROUGH PASSAGE FOR THE FORECAST AREA. THUS...CANT RULE OUT SOME CRITICAL FIRE WEATHER AREAS...MOST LIKELY FAVORING THE EAST...WHERE TEMPERATURES WOULD BE ABOVE NORMAL FOR THE LONGEST. COOLING EXPECTED ACROSS THE WEST ON THURSDAY AND SPREAD ACROSS THE ENTIRE AREA ON FRIDAY. THIS AIR MASS APPEARS TO BE LESS CHILLY COMPARED TO THE CURRENT ONE. VENTILATION WOULD BE QUITE HIGH WEDNESDAY AND THURSDAY AND PROBABLY LOWER SOME ON FRIDAY. CONFIDENCE IS AT LEAST MODERATE FOR THIS SCENARIO. 50 && .ABQ WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 7 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...NMZ103-104-108. FREEZE WARNING FROM 1 AM TO 9 AM MDT SATURDAY FOR THE FOLLOWING ZONES...NMZ518-519-524-530>534. && $$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
940 PM EDT FRI OCT 4 2013 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO RESIDE OVER THE REGION THROUGH SUNDAY. INCREASING MOISTURE AHEAD OF BOTH A COLD FRONT...AND TROPICAL STORM KAREN...WILL SPREAD INTO THE REGION FOR THE START OF THE NEXT WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 940 PM FRIDAY... LITTLE CHANGE TO THE OVERNIGHT FORECAST NEEDED AS HIGH PRESSURE REMAINS PERSISTENT OVER THE CAROLINAS. SKIES HAVE CLEARED AND WINDS. DEWPOINTS HAVE RECOVERED ANOTHER 2 TO 4 DEGREES SINCE 24 HOURS AGO...MAINLY ACROSS THE SOUTH... AND DEWPOINT DEPRESSIONS ARE ALREADY LESS THAN 5 DEGREES AT MANY OBSERVING SITES. RH CROSS SECTIONS FAVOR SOUTHERN AREAS FOR FOG...AND THE RECENT HRRR RUNS SUPPORT THIS. LOWS MOSTLY IN THE 60-63 RANGE. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... AS OF 255 PM FRIDAY... SATURDAY AND SATURDAY NIGHT...HIGH PRESSURE PERSISTS...WITH MID-LEVEL HEIGHTS ACTUALLY RISING FOR A TIME SATURDAY BEFORE BEGINNING TO FALL AGAIN SATURDAY NIGHT. BUFR SOUNDINGS FROM BOTH THE NAM AND THE GFS SUGGEST A COUPLE OF DEGREES OR SO OF WARMING ALOFT AROUND 500MB SATURDAY...WITH SOME 850MB MOISTURE AVAILABLE ONCE AGAIN SUGGESTIVE OF SOME DIURNAL CUMULUS WITH MIXING SATURDAY MORNING INTO THE AFTERNOON. SUBSIDENCE CONTINUES TO DOMINATE...AND K INDICES ACTUALLY FALL SOMEWHAT ON THE GFS DURING THE DAY SATURDAY. ANOTHER DRY DAY ANTICIPATED WITH LIGHT WINDS EARLY INCREASING A TOUCH...UNDER 10KT...AND SHOWING A SOUTHERLY COMPONENT BEFORE AGAIN DIMINISHING TO FAIRLY LIGHT SOUTHERLY SATURDAY NIGHT. 1000-850MB THICKNESSES SUPPORT HIGHS AROUND THE MOS GUIDANCE...MANY UPPER 80S AND A FEW READINGS AT 90. AVAILABLE LOW-LEVEL MOISTURE SUPPORTS A GREATER PROBABILITY OF AREAS OF FOG ACROSS CENTRAL NORTH CAROLINA LATE SATURDAY NIGHT INTO SUNDAY MORNING...AND HAVE AGAIN CONTINUED THIS IN THE GRIDDED AND WORDED FORECASTS. OVERNIGHT LOWS SATURDAY NIGHT MAINLY LOWER 60S. -DJF SUNDAY...WINDS ALOFT WILL BACK TO SOUTHWESTERLY AS THE MID-UPPER RIDGE AXIS SHIFTS EAST AND OFFSHORE...WHICH WILL PROMOTE A GRADUAL INCREASE IN MID TO ESPECIALLY HIGH LEVEL MOISTURE THROUGHOUT THE DAY SUNDAY. THE COMBINATION OF THE INCREASING CLOUDS AND THE EASTWARD DEPARTURE OF THE RIDGE ALOFT WILL LIKELY RESULT IN TEMPERATURES UP TO A FEW DEGREES COOLER THAN THOSE OF SAT - OR WITHIN A COUPLE OF DEGREES EITHER SIDE OF 85. THE TIGHTENING MSL PRESSURE GRADIENT IN RETURN FLOW WILL ALSO PROMOTE THE DEVELOPMENT OF A SOUTHERLY BREEZE THAT WILL PEAK IN THE 10-15 KT RANGE OVER THE WESTERN PIEDMONT ACCORDING TO MIXED LAYER WINDS DEPICTED BY BUFR FORECAST SOUNDINGS. DESPITE THE INCREASING MAINLY HIGH CLOUDS...PRECIPITATION CHANCES WILL REMAIN RELATIVELY LOW. WILL ACCORDINGLY TRIM INHERITED PRECIPITATION CHANCES AND CONFINE A SLIGHT CHANCE TO ROUGHLY THE SOUTHERN HALF OF THE CWFA...TO ACCOUNT FOR THE PROPAGATION OF SHOWERS THAT FORM OWING TO ONSHORE FLOW/FRICTIONAL CONVERGENCE AND WEAK HEIGHT FALLS ALOFT...IN A WEAKLY INHIBITED AND UNSTABLE ENVIRONMENT ALONG AND INVOF COASTAL AREAS. -MWS && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... AS OF 255 PM FRIDAY... SUN NIGHT THROUGH MON NIGHT...CONFIDENCE IS HIGH THAT THE REMNANTS OF T.S. KAREN WILL INTERACT WITH A POWERFUL UPPER TROUGH AND ATTENDING FRONTAL ZONE AND CONSEQUENTLY AFFECT CENTRAL NC EARLY NEXT WEEK. HOWEVER...STILL-LARGE MODEL SPREAD YIELDS BELOW AVERAGE FORECAST CONFIDENCE OF THE ASSOCIATED SENSIBLE WEATHER IMPACTS AND TIMING THEREOF. INTERPOLATION OF THE LATEST NHC AND WPC FORECAST TRACKS DEPICT A NORTHEASTWARD PATH DIRECTLY THROUGH THE NC PIEDMONT MON-EARLY MON NIGHT...WITH FRONTAL PASSAGE AND DRY CONDITIONS BY EARLY TUE. PATTERN RECOGNITION/CONCEPTUAL MODELS SUGGEST THE ASSOCIATED PRECIPITATION SHIELD WILL SHIFT WEST OF TRACK AS THE REMNANT LOW IS INFLUENCED BY THE POWERFUL UPPER TROUGH/LOW FORECAST TO MIGRATE FROM THE ROCKIES TODAY TO THE UPPER MIDWEST MON MORNING. SO WHILE IT APPEARS THAT MOST OF OUR REGION WILL RECEIVE AT LEAST A BENEFICIAL SOAKING RAIN...SOME AREAS - IMMEDIATELY LEFT OF THE EVENTUAL LOW TRACK - WILL LIKELY EXPERIENCE A MULTI-INCH RAIN EVENT. THE ASSOCIATED LOW-DEEP LAYER SHEAR AND AT LEAST POCKETS OF MARGINAL INSTABILITY WILL ALSO SUPPORT A THREAT OF SEVERE WEATHER WITH THE PASSAGE OF THE LOW...MON AFTERNOON. A SEPARATE BAND OF CONVECTION... THOUGH LIKELY SUB-SEVERE WITH GUSTY WINDS...MAY ALSO ACCOMPANY THE FRONT MON NIGHT. TEMPERATURES THROUGH THE PERIOD ARE EXPECTED TO RANGE FROM THE MIDDLE TO UPPER 60S IN A MIXED AND MOIST BOUNDARY LAYER SUN NIGHT...TO 70S (WITH POCKETS OF LOWER 80S WHERE ANY BINOVC OCCUR) MON...TO UPPER 50S TO MIDDLE 60S IN POST-FRONTAL CAA MON NIGHT. TUE THROUGH FRI...MEDIUM RANGE DETERMINISTIC AND ENSEMBLE MODEL SPREAD INCREASES FURTHER DURING THE MIDDLE AND END OF THE WEEK WITH RESPECT TO HOW QUICKLY THE PARENT UPPER LOW LIFTS FROM THE UPPER MIDWEST TO SE CANADA...AS WELL AS HOW MUCH POSITIVELY-TILTED TROUGHING ALOFT IS LEFT BEHIND OVER THE SE US. DESPITE THESE DIFFERENCES...THE ASSOCIATED SENSIBLE WEATHER IMPACTS FOR OUR REGION ARE SIMILAR. THAT IS...THE EXPANSION INTO THE EASTERN US OF PACIFIC HIGH PRESSURE AND ASSOCIATED MILD AND DRY CONDITIONS...WITH ANY UNSETTLED WEATHER RESULTING FROM LINGERING POSITIVELY-TILTED TROUGHING ALOFT HOLDING TO OUR SOUTH - OVER THE SW NORTH ATLANTIC AND CARIBBEAN. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 745 PM FRIDAY... AREAS OF FOG ARE EXPECTED DEVELOP LATE TONIGHT BETWEEN 06 TO 12Z......WITH THE HIGHEST PROBABILITY AND CORRESPONDINGLY LOWER VISIBILITIES EXPECTED IN THE EAST AT KRWI AND KFAY. BEYOND THE 18Z VALID TAF PERIOD...AREAS OF FOG WILL BE POSSIBLE AGAIN EARLY SUNDAY MORNING...OTHERWISE EXPECT PREDOMINATELY VFR CONDITIONS THROUGH THE WEEKEND. MOISTURE ASSOCIATED WITH REMNANTS OF TS KAREN WILL SPREAD INTO THE AREA LATE SUNDAY NIGHT AND INTO MONDAY. SUB-VFR CONDITIONS WILL BE POSSIBLE AGAIN LATE SUNDAY NIGHT AND MONDAY MORNING WITH WIDESPREAD SHOWERS AND STORMS MONDAY AFTERNOON THROUGH MONDAY NIGHT WITH CORRESPONDING AREAS OF SUB-VFR CONDITIONS. WIDESPREAD VFR CONDITIONS ARE LIKELY TO RETURN BY TUESDAY AFTERNOON AS A COLD FRONT PUSHES EAST AND OFFSHORE. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...SMITH SHORT TERM...DJF/MWS LONG TERM...MWS AVIATION...CBL
AREA FORECAST DISCUSSION
NWS TULSA OK
910 PM CDT FRI OCT 4 2013 ...UPDATE... .DISCUSSION... THUNDERSTORMS CONTINUED TO RIDE ALONG THE INITIAL WIND SHIFT OF THE COLD FRONT THIS EVENING FROM SOUTHWEST OKLAHOMA TO JUST WEST OF OSAGE COUNTY AS OF 9 PM THIS EVENING. THE DRIER AIR REMAINED FURTHER WEST ACROSS NORTHWEST OKLAHOMA. THESE THUNDERSTORMS WILL PUSH INTO THE CWA OVER THE NEXT HOUR AS THE FRONT CONTINUES TO PUSH EAST SOUTHEASTWARD. WITH THE LOSS OF DAYTIME HEATING THE CAP HAS BEGUN TO STRENGHTEN ACROSS THE CWA...HOWEVER DEEP LAYER SHEAR NEAR AND JUST BEHIND THE FRONT WILL ALLOW FOR THE POTENTIAL FOR SOME STORMS TO BECOME STRONG TO SEVERE. LARGE HAIL AND STRONG WINDS CONTINUE TO BE THE MAIN THREATS WITH THIS ACTIVITY. GREATEST POTENTIAL FOR ANY SEVERE STORMS LOOKS TO BE MAINLY NORTHWEST OF INTERSTATE 44 OVER THE NEXT FEW HOURS. THE SEVERE THUNDERSTORM WATCH FOR OSAGE AND PAWNEE COUNTIES REMAINS IN EFFECT UNTIL 3Z. LATEST RUNS OF THE HRRR AND THE LOCAL IN-HOUSE MODEL INDICATE THAT THUNDERSTORMS COULD BE NEAR EAST CENTRAL OKLAHOMA BY 06Z AND INTO SOUTHEAST OKLAHOMA AND NORTHWEST ARKANSAS BY 9Z. INSTABILITY ACROSS THE REST OF THE CWA SHOULD WEAKEN OVERNIGHT AS THE CAP CONTINUES TO STRENGHTEN...THOUGH AN ISOLATED STRONG TO SEVERE STORM COULD BE POSSIBLE. GUSTY NORTHWESTERLY WINDS IN THE 20 TO 30 MPH RANGE HAVE BEEN OBSERVED BEHIND THE FRONT WITHIN THE DRIER/COOLER AIR AND WILL CONTINUE TO FILTER INTO THE REGION OVERNIGHT. TEMPERATURES BY EARLY SATURDAY MORNING LOOK BE AROUND 50 TO LOWER 50S NEAR THE KANSAS BORDER TO THE 60S FOR FAR SOUTHEAST OKLAHOMA AND WEST CENTRAL ARKANSAS. EVENING UPDATE WILL BE TO ADJUST POPS/WX/SKY GRIDS BASED ON LATEST TRENDS AND TIMING...WHILE THE REST OF THE FORECAST SEEMS TO BE HANDLING WELL AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... TUL 53 64 47 68 / 90 20 10 0 FSM 66 73 46 68 / 80 70 10 0 MLC 56 60 44 70 / 90 60 10 0 BVO 51 65 43 66 / 80 20 10 0 FYV 60 65 42 63 / 80 80 10 10 BYV 63 68 44 62 / 80 80 10 10 MKO 56 59 45 68 / 90 60 10 0 MIO 53 61 43 64 / 90 50 10 10 F10 53 60 46 69 / 90 40 10 0 HHW 66 73 46 72 / 80 50 10 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM...20 LONG TERM....99
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
608 PM CDT FRI OCT 4 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 330 PM CDT FRI OCT 4 2013 FORECAST CONCERNS ARE ON SEVERE THUNDERSTORM POTENTIAL TONIGHT AND THE POSSIBILITY OF A FEW SEVERE STORMS IN CENTRAL WISCONSIN LATE SATURDAY MORNING INTO EARLY SATURDAY AFTERNOON. LATEST SURFACE OBSERVATIONS SHOWED SURFACE LOW PRESSURE OVER CENTRAL NEBRASKA...LIFTING NORTHEAST. A WARM FRONT EXTENDED SOUTHEAST THROUGH SOUTHWEST AND CENTRAL IOWA. THE FRONT WILL LIFT NORTH LATE THIS AFTERNOON INTO THIS EVENING AND BE THE FOCUS FOR STRONG TO SEVERE THUNDERSTORM DEVELOPMENT AS A POTENT UPPER LOW PUSHES EAST ACROSS THE NEBRASKA PANHANDLE. THE WARM FRONT IS EXPECTED TO LIFT NORTH INTO NORTHERN IOWA AND PERHAPS EXTREME SOUTHWEST WISCONSIN THIS EVENING. STRONG 850 MB MOISTURE TRANSPORT FOCUSES INTO THE FRONT THIS EVENING...LEADING TO SHOWERS AND THUNDERSTORMS DEVELOPING OVER NORTHEAST IOWA...SOUTHEAST MINNESOTA AND PORTIONS OF SOUTHWEST WISCONSIN. MEANWHILE THE SURFACE LOW WILL LIFT NORTH INTO SOUTHEAST SOUTH DAKOTA AS THE LOW OCCLUDES. A TRIPLE POINT LIFTS NORTHEAST FROM NORTHEAST IOWA INTO SOUTH CENTRAL MINNESOTA LATE IN THE EVENING. THE 04.17 HRRR SHOWS ISOLATED STRONG STORMS DEVELOPING ALONG THE FRONT. STORMS ALSO DEVELOP OVER WESTERN IOWA EARLY THIS EVENING CLOSER TO THE OCCLUSION. THESE STORMS WILL LIKELY BE SUPERCELLS...CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS AND ISOLATED TORNADOES. THE STORMS FURTHER TO THE NORTH OVER THE FORECAST AREA...SHOULD BE NORTH OF THE WARM FRONT AND ELEVATED IN NATURE. 1-7 KM BULK SHEAR VALUES HOVER RIGHT AROUND 30 KTS DURING THE EVENING HOURS SO CANNOT RULE OUT ISOLATED SEVERE STORMS CAPABLE OF PRODUCING LARGE HAIL...HEAVY RAINFALL...AND POSSIBLY DAMAGING WINDS. THE HIGHEST CHANCES FOR SEVERE WEATHER WILL BE OVER NORTHEAST IOWA AND SOUTHEAST MINNESOTA...WEST OF HIGHWAY 52. A FEW OF THESE STRONGER STORMS COULD MAINTAIN INTENSITY INTO PORTIONS OF WESTERN WISCONSIN BUT SHOULD THEN WEAKEN AS THEY MOVE EAST...BUT STILL CAPABLE OF PRODUCING HEAVY RAINFALL. THE 850 MB MOISTURE TRANSPORT GRADUALLY SHIFTS EAST INTO WESTERN WISCONSIN OVERNIGHT WITH WIDESPREAD SHOWERS AND STORMS PERSISTING. THE MAIN THREAT FROM THE STORMS SHOULD GRADUALLY SHIFT TOWARDS HEAVY RAIN LATE IN THE NIGHT. A COLD FRONT THEN PUSHES EAST ACROSS THE REGION EARLY SATURDAY MORNING AND SHOULD BE POSITIONED RIGHT ALONG THE MISSISSIPPI RIVER BY THE MID TO LATE MORNING HOURS. IF ENOUGH INSTABILITY CAN BUILD AHEAD OF THE FRONT...THERE IS THE POSSIBILITY OF SEEING A FEW STRONG TO SEVERE STORMS OVER CENTRAL WISCONSIN. THE MAIN HAZARDS FROM THESE STORMS WOULD BE DAMAGING WINDS. SHOWERS AND STORMS WILL END FROM WEST TO EAST SATURDAY AFTERNOON AS A DRY SLOT PUSHES INTO THE REGION. TEMPERATURES SHOULD FALL ACROSS THE AREA SATURDAY AFTERNOON IN THE WAKE OF THE COLD FRONT. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 330 PM CDT FRI OCT 4 2013 MOST OF THE FORECAST AREA WILL REMAIN IN THE DRY SLOT SATURDAY NIGHT...WITH THE EXCEPTION OF NORTH CENTRAL WISCONSIN WHERE A FEW SHOWERS MAY LINGER. PLAN ON A COOLER NIGHT WITH LOWS FALLING INTO THE 40S. A FEW 30S CANNOT BE RULED OUT OVER CENTRAL WISCONSIN. THE UPPER LOW MOVES INTO INTO WESTERN IOWA ON SUNDAY AND EVENTUALLY INTO WESTERN ILLINOIS SUNDAY NIGHT. SHOWERS WRAPPING AROUND THE LOW LOOK TO MOVE INTO THE REGION SUNDAY AND WILL LIKELY CONTINUE INTO SUNDAY NIGHT AS THE LOW PROGRESSES EAST. THE LOW THEN LOOKS TO MOVE INTO THE EASTERN GREAT LAKES LATE ON TUESDAY WITH HIGH PRESSURE BUILDING INTO THE AREA IN ITS WAKE. HIGH PRESSURE THEN BUILDS OVER THE AREA WEDNESDAY INTO THURSDAY WITH DRY AND QUIET WEATHER EXPECTED...OUTSIDE OF THE POSSIBILITY OF OF SOME EARLY MORNING VALLEY FOG. A TROUGH IS EXPECTED TO DIG INTO THE SOUTHWEST CONUS LATE IN THE WEEK. SOUTHWEST FLOW LOOKS TO DEVELOP OVER THE UPPER MISSISSIPPI RIVER VALLEY LATE FRIDAY INTO SATURDAY. FORECAST MODELS SHOWS THE TROUGH EJECTING INTO THE CENTRAL AND NORTHERN PLAINS...WILL HAVE TO KEEP A VERY CLOSE EYE ON THIS SYSTEM OVER THE NEXT SEVERAL MODEL RUNS. && .AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING) ISSUED AT 608 PM CDT FRI OCT 4 2013 SOME CONVECTION DEVELOPING ALONG A WEAK BOUNDARY ACROSS NORTHERN IOWA. ACTIVITY IS MOVING PRIMARILY TO THE NORTH/NORTHEAST AND SHOULD THE GREATEST POTENTIAL TO IMPACT KRST IF IT HOLDS TOGETHER AS IT MOVES NORTH. AROUND 500 J/KG OF MU CAPE EXITS AS FAR NORTH AS THE I90 CORRIDOR SO WILL SHOW A VCTS AT KRST FOR THIS ACTIVITY. THE FOCUS THEN SHIFTS TO HOW FAST THE CONVECTION NEAR THE MISSOURI RIVER WILL TRANSLATE INTO THE AREA. THE 04.21Z HRRR SEEMS TO BE HANDLING THIS WELL AND INDICATES IT COULD START COMING IN BY MID EVENING AND THEN MOVE OFF TO THE EAST BETWEEN 06 AND 08Z. BRIEF BREAK IN THE ACTION BEFORE THE COLD FRONT COMES IN EARLY SATURDAY MORNING WITH ANOTHER ROUND OF CONVECTION. THIS ACTIVITY COULD POTENTIALLY STICK AROUND INTO THE MIDDLE OF THE AFTERNOON...EVEN FOR A FEW HOURS AFTER THE FRONT GOES THROUGH WITH THE UPPER LEVEL SYSTEM HANGING BACK WELL TO THE WEST. THE WINDS SHOULD GO AROUND TO SOUTHWEST DURING THE AFTERNOON BEHIND THE PASSAGE OF THE FRONT. CEILINGS LOOK TO REMAIN IFR AT BOTH SITES FOR MUCH OF THE PERIOD WITH VISIBILITIES PRIMARILY MVFR. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...04
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
322 AM CDT SAT OCT 5 2013 .DISCUSSION... 322 AM...PRIMARY FORECAST CONCERN/CHALLENGE IS POTENTIAL FOR SEVERE WEATHER INTO THIS EVENING. FRONTAL BOUNDARY HAS BEEN SLOWLY LIFTING NORTH ACROSS NORTHERN IL WITH SOUTHERLY WINDS REACHING A RFD/ORD LINE. WHILE VISIBILITIES HAVE REMAINED GENERALLY IN THE 1-3SM RANGE NEAR THE FRONT...ACROSS FAR NORTHEAST IL SATELLITE IMAGERY SUGGESTS FOG IS RATHER THICK OVER NORTHERN SECTIONS OF LAKE AND MCHENRY COUNTIES WITH UGN REPORTING 1/4SM FOR THE PAST FEW HRS. WHILE THIS WILL LIKELY BE SHORT-LIVED...OPTED TO ISSUE A DENSE FOG ADVISORY FOR THESE TWO COUNTIES THROUGH 8AM. AS WINDS TURN SOUTHERLY...VISIBILITIES WILL IMPROVE. SOUTH OF THE FRONT...FAIRLY IMPRESSIVE AIRMASS THIS FAR NORTH FOR EARLY OCTOBER WITH DEWPOINTS IN THE UPPER 60S AND MOISTURE IS EXPECTED TO POOL THIS MORNING WITH PERHAPS LOWER 70 DEWPOINTS ACROSS MUCH OF THE AREA. UPSTREAM CLOUD COVER IS MOSTLY MID/HIGH CLOUDS THAT WILL LIKELY THIN THROUGH MID MORNING...SO APPEARS MUCH OF THIS MORNING WILL BE MOSTLY SUNNY/PARTLY CLOUDY. THIS SHOULD AID TEMPERATURES RISING INTO THE LOWER 80S ACROSS THE SOUTHEAST HALF OF THE AREA AND WITH SUCH A MOIST AIRMASS IN PLACE...ONCE HEATING BEGINS...POSSIBLE FOR ISOLATED THUNDERSTORMS THIS MORNING. BULK OF THE ACTIVITY HOWEVER APPEARS TO HOLD OFF UNTIL THIS AFTERNOON...BOTH FROM INCREASING DIURNALLY DRIVEN STORMS BUT ALSO AS A SHORTWAVE LIFTS NORTHEAST ACROSS NORTH CENTRAL ILLINOIS THIS AFTERNOON INTO THIS EVENING...AHEAD OF THE APPROACHING COLD FRONT. WITH THUNDERSTORMS SPREADING EAST THIS EVENING BUT SLOWING. OVERALL CONFIDENCE REGARDING THIS SCENARIO IS SOMEWHAT LOW IN ADDITION TO THE POTENTIAL FOR SEVERE WEATHER. THE MAIN SEVERE WEATHER THREAT WILL BE DAMAGING WINDS GUSTS BUT LACK OF STRONG SHEAR ALOFT WOULD SUGGEST THESE WOULD BE MORE ISOLATED...RATHER THEN A LINE OF STRONG/SEVERE STORMS. IN ADDITION...THE VERY MOIST LOW LEVELS WILL YIELD LOW LCL HEIGHTS AND MODELS ARE IN FAIR AGREEMENT WITH SURFACE WINDS BACKING SOME THIS AFTERNOON. THUS INDIVIDUAL CELLS THAT FORM AWAY FROM CLUSTERS OR LINES OF CONVECTION WILL HAVE SOME POTENTIAL TO PRODUCE A TORNADO. FORECAST PRECIPITABLE WATER VALUES OF 1.5 INCHES OR HIGHER WILL LEAD TO LOCALLY VERY HEAVY RAIN AND WITH LITTLE CHANGE TO STORM MOTION...GENERALLY SOUTHWEST TO NORTHEAST...ANY TRAINING OF STORMS COULD EASILY CAUSE FLOODING CONCERNS. ACTIVITY WILL SLOWLY SHIFT EAST LATE TONIGHT INTO SUNDAY MORNING AND HAVE INCLUDED CHANCE POPS EAST OF I-57 INTO THE MORNING. UNCERTAINTY HAS INCREASED WITH THE ARRIVAL OF THE 00Z ECMWF WHICH IS CONSIDERABLY FASTER THAN OTHER 00Z GUIDANCE WITH THE PROGRESSION OF THE UPPER LOW EAST ACROSS THE LAKES REGION. SUNDAY WAS SHAPING UP TO BE MAINLY DRY WITH PERHAPS SOME INSTABILITY SHOWERS ARRIVING IN THE WEST BY EVENING. AND WITH THE POSSIBILITY OF SOME SUNSHINE...TEMPS PERHAPS IN THE 60S AND WHILE THAT WILL BE MUCH COLDER THAN TODAY...IT WOULD ONLY BE A FEW DEGREES BELOW NORMAL. A FASTER SHIFT EAST OF THE UPPER LOW WILL ALSO END THE SHOWER POTENTIAL MONDAY OR MONDAY EVENING...RATHER THAN TUESDAY MORNING WITH THE SLOWER SOLUTIONS. CHANGES TO THE SUNDAY-TUESDAY TIME PERIOD CAN BE EXPECTED DEPENDING ON THE SPEED OF THE UPPER LOW. HOWEVER...THE WARMING TREND STILL LOOKS ON TRACK...PERHAPS JUST DELAYED BY A DAY OR SO WITH HIGHS BACK INTO THE 70S BY WEDNESDAY AND THURSDAY. CMS && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LOWERING VISIBILITY AND CIGS INTO IFR CATEGORY INTO OVERNIGHT. * NORTHEAST WINDS BECOMING EAST THEN SOUTHEAST TONIGHT WITH SPEEDS MOST OF TIME BELOW 10 KT. * SMALL CHANCE OF TSRA SAT MORNING GRADUALLY INCREASING INTO MID- AFTERNOON. * THUNDERSTORMS LIKELY 22Z-00Z SOME OF WHICH COULD BE STRONG. BEACHLER //DISCUSSION...UPDATED 06Z... VERY CHALLENGEING AVIATION CONDITIONS ARE IN STORE FOR THE NEXT 24 HOURS ACROSS THE REGION...ESPECIALLY OVER NORTHERN IL/NORTHWEST IN. A STALLED FRONTAL BOUNDARY WAS ORIENTED ACROSS NORTHERN IL...WHICH HAS RESULTED IN LIGHT WINDS TO AT TIMES CALM FOR DPA/ORD/MDW/GYY. IN ADDITION VERY MOIST AIR WAS OVER THESE AIRFIELDS AND HAS RESULTED IN VSBYS BEING REDUCED. IT APPEARS ORD SHOULD ONLY REDUCE TO ARND 3-4SM OVERNIGHT...HOWEVER ELSEWHERE MDW/GYY/DPA/RFD WILL LIKELY SEE VSBYS DOWN BTWN 1/2SM AT RFD/DPA TO 2-3SM AT GYY/MDW. IR IMAGERY INDICATED SOME IFR CIGS WERE DEVELOPING OVER FAR NORTHWEST IL WHICH HAS BROUGHT CIGS DOWN AT RFD...AND IT IS POSSIBLE CIGS COULD DROP TO ARND 200-300FT AGL BEFORE DAYBREKA THEN SLOWLY IMPROVE AFT DAYBREAK. THEN THE FOCUS TURNS TOWARDS CONVECTIVE TIMING/PLACEMENT LATER TODAY. AFTER SUNRISE VSBYS SHUD BE SLOW TO IMPROVE WITH JUST A CIRRUS SHIELD EXPECTED OVERHEAD TO START THE DAY. THE COLD FRONT WILL BE WELL WEST OF THE REGION...HOWEVER STEADILY PIVOTING EAST TOWARDS NORTHERN IL AIRFIELDS. GUIDANCE CONTINUES TO INDICATE WINDS BY MID MORNING WILL BECOME SOUTHERLY ARND 10KT AND OCCASIONAL GUSTS TO THE MID-TEENS ARE LIKELY. CLOUDS WILL THICKEN BY MIDDAY WITH A DECK ARND 3-4KFT AGL. WITH CONSIDERABLE ELEMENTS SUGGESTING CONVECTION WILL BE FIRING ARND 18-19Z...IT IS LIKELY THAT THE BEST CHC FOR CONVECTION WILL BE ARND 19Z-00Z...AND THE BETTER COVERAGE WILL FALL WITHIN A 22-00Z TIMEFRAME. WINDS WILL SLOWLY TURN TO THE 240-260 DEG RANGE FRONTAL PASSAGE...WITH RAIN/THUNDER SLOWLY ENDING AFT 03-06Z SUN. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN STABLE/SLIGHTLY LOWERING TREND OF CIG...MEDIUM CONFIDENCE ON VISIBILITY. MEDIUM CONFIDENCE ON HOW LOW CIG AND VISIBILITY WILL FALL. * MEDIUM-HIGH CONFIDENCE IN WIND FORECAST. * MEDIUM CONFIDENCE ON TSRA TIMING OF 21Z-02Z. BEACHLER //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...VFR DURING THE DAY WITH MVFR CIGS AND CHC SHRA DURING THE NIGHT. MONDAY...CHC OF MVFR AND SLT CHC OF SHRA DURING THE MORNING. TUESDAY-THURSDAY...MAINLY VFR. MTF && .MARINE... 341 PM CDT A TROUGH OF LOW PRESSURE AND ASSOCIATED FRONTAL BOUNDARY ARE SITUATED ACROSS THE UPPER MISSISSIPPI VALLEY EAST ACROSS TO THE SOUTHERN GREAT LAKES REGION...WITH THESE FEATURES STEMMING FROM AN AREA OF LOW PRESSURE SITUATED OVER THE CENTRAL PLAINS. ITS THESE FEATURES THAT ARE PROVIDING...AND WILL CONTINUE TO PROVIDE DRASTICALLY VARYING CONDITIONS ACROSS THE ENTIRE LAKE. A LIGHTER WIND FIELD IS CURRENTLY PRESENT OVER THE SOUTHERN PORTIONS OF THE LAKE WHERE THE PRESSURE GRADIENT IS RELAXED...BUT WITH SPEEDS INCREASING TO 15 TO 25 KT FOR THE FAR NORTHERN PORTIONS OF THE LAKE. THIS BOUNDARY WILL LIFT BACK NORTH ACROSS THE LAKE TONIGHT INTO SATURDAY WHILE THIS LOW PRESSURE SYSTEM SLOWLY TRACKS NORTHEAST TOWARDS THE MISSISSIPPI VALLEY. AS THIS OCCURS...EXPECT A GRADUAL TRANSITION TO THE EAST SOUTHEAST WITH SPEEDS INCREASING ACROSS THE ENTIRE LAKE. EXPECT THE HIGHEST SPEEDS OF 30KT TO BE OBSERVED ACROSS THE NORTH...WITH THESE EASTERLY WINDS/SPEEDS LIKELY PERSISTING INTO EARLY SATURDAY NIGHT. EXPECT THIS LOW TO THEN CONTINUE NORTHEAST AND REACH THE CENTRAL GREAT LAKES LATE SATURDAY NIGHT INTO SUNDAY...AND THEN CONTINUE EAST TOWARDS THE EASTERN GREAT LAKES SUNDAY NIGHT INTO MONDAY. AS THIS OCCURS...EXPECT SPEEDS TO DIMINISH WHILE BECOMING MORE SOUTHERLY ON SUNDAY AND THEN WEST/NORTHWEST INTO MONDAY. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...DENSE FOG ADVISORY...ILZ005-ILZ006 UNTIL 8 AM SATURDAY. 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 301 AM CDT Sat Oct 5 2013 .DISCUSSION... ISSUED 301 AM CDT Sat Oct 5 2013 After a stormy day across central Illinois today, much cooler weather will arrive for early next week. 07z/2am surface map shows 1000mb low centered over South Dakota, with cold front extending southeastward into Iowa/Missouri. Very warm and humid airmass remains in place ahead of the front, with temps in the 70s and dewpoints in the upper 60s. Meanwhile, sharply colder conditions are noted further west behind the boundary where readings are only in the 30s across the Dakotas and Nebraska. SHORT TERM...Today through Monday Deep upper-level low currently spinning over South Dakota will be the main weather-maker across the region for the next couple of days. As this system slowly wobbles eastward, it will push a strong cold front through central Illinois later today into tonight. 00z models have slowed eastward progression of the front just a bit, bringing it into the Illinois River Valley by around 21z/4pm. Given occluded nature of system, this slower trend seems reasonable. As such, have lowered POPs across the western KILX CWA into the chance category during the morning hours, opting to hit POPs hardest during the afternoon and evening as best forcing arrives. The front will have plenty of moisture to work with as forecast soundings show precipitable water values greater than 1.50. The airmass will also be moderately unstable, with CAPE values ranging from 1500 to 2000J/kg. Main mitigating factor for widespread severe weather will be weak wind fields/shear. While instability axis will be positioned across Illinois and the Ohio River Valley this afternoon, strongest wind shear will be displaced well to the west across Iowa and Missouri. With these two key severe weather parameters not coinciding with one another, am not expecting a major severe event today. Thunderstorms will increase in areal coverage during the afternoon, with perhaps a few of them producing severe wind gusts. Outside of thunderstorms, it will be another very warm day with highs ranging from the middle 70s west to the lower 80s east. Based on expected speed of front, temps will likely drop into the 60s along/west of the Illinois River late this afternoon after FROPA. Due to slower frontal movement, have increased POPs tonight. Will carry likely to categorical POPs along/east of the Illinois River during the evening, with best rain chances shifting to the I-57 corridor and eastward after midnight. Once front passes, skies will clear across the Illinois River Valley late tonight. Low temperatures will range from the lower 40s far west around Galesburg and Rushville, to the upper 50s near the Indiana border. Will linger some shower chances along/east of I-57 through Sunday morning, as front slowly progresses eastward across Indiana. Mid-level dry slot behind front and immediately ahead of slowly approaching upper low will allow skies to be partly to mostly sunny across the central and western CWA Sunday morning before clouds begin to increase from the west by late in the day. Given slow movement of system, have pulled back POPs from previous forecast to feature only a slight chance for showers across the far west Sunday afternoon. Cold core upper low will track overhead Sunday night into Monday, creating a chilly and showery weather pattern. NAM/GFS/GEM are all in excellent agreement with the position of the 500mb closed low over Illinois by 12z Mon. Meanwhile, the latest run of the ECMWF has made a drastic shift from its previous solution, now placing the low over Michigan Monday morning. Will reject the ECMWF in favor of the model consensus here. As a result, have added low POPs for showers both Sunday night and Monday. Have also lowered highs considerably for Monday, with readings only reaching the lower 60s. LONG TERM...Tuesday through Friday Once upper low lifts further northeast, upper heights will once again be on the rise across the central and eastern CONUS next week. 850mb temps respond accordingly, with readings back into the 14 to 16c range by Thursday and Friday. This will support highs well into the 70s and perhaps the lower 80s by the end of the week. Barnes && .AVIATION... ISSUED 1151 PM CDT Fri Oct 4 2013 Latest runs of the high resolution models and the 00z NAM/GFS indicate that the aviation forecast for central IL TAF sites needs few changes from the previous issuance. Still looking for light fog/mist to form toward early morning, although it is looking less likely that a stratus ceiling will develop. Plenty of high and mid clouds from upstream convective debris will move into central and eastern Illinois overnight. Radar trends, as well as the latest HRRR and RAP forecasts, indicating that convective remnants to approach central Illinois shortly after daybreak ahead of the cold front. Plenty of moisture, instability and increasing low/mid level wind shear will be present for t-storms to redevelop in a linear fashion by early afternoon. Maintained the predominant thunderstorm forecast to account for this expected development and movement of a line of storms. The higher resolution models were also indicating that the front will move a bit slower than previously forecast. Thus, the 06z TAFs will extend the thunderstorms a couple of hours from the previous forecast, and also hold off the frontal passage/wind shift until late afternoon- evening. Miller && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
105 AM CDT SAT OCT 5 2013 .DISCUSSION... 804 PM CDT THIS EVENING...WARM FRONT STRETCHES FROM NEAR DBQ ESE TO JOT...THEN EAST TO VPZ. TEMPERATURES CONTINUE TO RUN IN THE MID TO UPPER 70S SOUTH OF THE FRONT...WITH DEWPOINTS INTO THE MID TO UPPER 60S. NORTH OF THE BOUNDARY...TEMPERATURES QUICKLY TAPER INTO THE MID 60S...WITH LOW DEW POINT DEPRESSIONS. FOG/LOW STRATUS ALREADY STARTING TO DEVELOP ACROSS THESE AREAS...AND SHOULD CONTINUE TO EXPAND OVERNIGHT. REMOVED PRECIP MENTION OVERNIGHT FOR ALL BUT THE NORTHERN TIER OF COUNTIES. LAST VISIBLE SATELLITE IMAGES BEFORE SUNSET SHOWED CU FIELD QUICKLY DISSIPATING...AND THE MAIN IMPETUS FOR ANY PRECIP OVERNIGHT IS NEAR THE IL/WI STATE LINE WHERE THE BEST FOCUSED ISENTROPIC ASCENT IS NOTED. FORECAST OTHERWISE ON TRACK WITH ONLY MINOR TWEAKS TO THE HOURLY TRENDS. DEUBELBEISS //PREV DISCUSSION... 240 PM FOR THE REMAINDER OF THE AFTERNOON THROUGH SATURDAY...THE MAIN CONCERN WILL BE SEVERE WEATHER POTENTIAL...WITH A SECONDARY CONCERN FOR TEMPERATURES. EARLY THIS AFTERNOON...CONVECTIVE ACTIVITY IS FOCUSING ON THE NOSE OF A STRONG LOW LEVEL JET POINTING INTO NRN IL...WHICH IS ENHANCING THE ISENTROPIC LIFT ALREADY IN PLACE AS WARM MOIST AIR CONTINUES TO STREAM INTO THE REGION. A SECONDARY FOCUS OF CONVECTIVE ACTIVITY IS A SFC TROUGH/SECONDARY WARM FRONT EXTENDING FROM NRN MO...THROUGH NRN IL AND NRN INDIANA. LATEST RADAR IMAGERY SHOWS THE WARM ADVECTION CONVECTION ALREADY INTO NWRN IL AND WITH COPIOUS AMOUNTS OF HEAT...TEMPS IN THE UPPERS 70S-LOW 80S...MOISTURE...DEWPOINTS IN THE UPPER 60S TO LOWERS 70S...AND INSTABILITY...MIXED LAYER CAPE OF 1500-2000 J/KG...EXPLOSIVE CONVECTION IS QUITE POSSIBLE WHERE ALL ELEMENTS LINE UP JUST RIGHT. WITH THE LOW LEVEL JET OF 30KT+ OVER THE AREA...STRONGER WINDS CAN CERTAINLY MIX DOWN TO THE SURFACE. THE ONE QUESTION MARK AT THIS TIME IS THE CLOUD COVER. LATEST SATELLITE IMAGERY SHOWS DENSE OVC OVER NRN IL...WITH MORE CONVECTIVELY DRIVEN CU/TOWERING CU SOUTH OF THE I-80 CORRIDOR. OF PARTICULAR CONCERN IS THE SECONDARY WARM FRONT...WHICH LIES IN THE AREA OF GREATER SFC INSOLATION SOUTH OF I-80. THE 12Z ILX SOUNDING INDICATES AT LEAST SOME VEERING OF WINDS THROUGH THE LOWER LEVELS WHICH WOULD HELP ADD SOME ROTATIONAL ASPECT TO STORMS...WHICH IN TURN COULD ADD A LARGE HAIL OR TORNADIC POTENTIAL TO THE STRONG WIND THREAT. ON TOP OF ALL OF THIS WILL BE A HEAVY RAINFALL POTENTIAL. THE 12Z KDVN SOUNDING INDICATES PWAT OF 1.4 INCHES...SO DEEP LAYER MOISTURE IS ALREADY IN PLACE. THE VARIOUS MODEL FORECAST PWATS INDICATE THAT A CORRIDOR OF EXTREME DEEP LAYER MOISTURE POOLING IN A CORRIDOR FROM SWRN WISCONSIN TO NERN KANSAS. WITH TIME AND PROGRESSION OF THE PATTERN...EXPECT THAT PWATS WILL ONLY INCREASE OVER THE LOCAL AREA THROUGH THE NEXT 36HRS. THE KDVN PWAT CLIMATOLOGY INDICATES THAT FOR OCTOBER...2 STANDARD DEVIATIONS FROM NORMAL IS 1.6 INCHES AND THE 99TH PERCENTILE PWAT IS 1.9 INCHES. THE LATEST MODEL RUNS SHOW PWAT INCREASING TO IN EXCESS OF 1.5 INCHES IN THE ENVIRONMENT AHEAD OF THE APPROACHING COLD FRONT. SO...FOR THE SEVERE WEATHER THREAT...TIMING AND COVERAGE ARE THE BIG QUESTIONS. ANTICIPATE THAT THE GREATEST SEVERE WEATHER THREAT WILL BE WITH THE COLD FRONT DUE TO THE GREATER SFC FORCING WHICH WILL LINE UP WITH THE FAVORABLE UPPER DYNAMICS WITH THE UPPER TROUGH. HOWEVER...THERE WILL STILL BE A MORE ISOLATED SEVERE WEATHER THREAT ACROSS THE LOCAL AREA SIMPLY DUE TO THE UNSEASONABLY STRONG LOWER LEVEL THERMODYNAMICS AND EXTREME DEEP LAYER MOISTURE. ALONG WITH THE SEVERE WEATHER THREAT...HEAVY RAINFALL AND LOCALIZED FLOODING WILL BE A CONCERN. THE PRIMARY LOCATION FOR POSSIBLE FLOODING WILL BE ALONG THE SECONDARY WARM FRONT AS RADAR TRENDS INDICATE THAT THE BOUNDARY ITSELF IS QUASISTATIONARY WHILE INDIVIDUAL CELLS TRACK TO THE EAST. THE CURRENT CONVECTIVE ACTIVITY ALONG THIS BOUNDARY IS CURRENTLY OVER NRN INDIANA...BUT RADAR SHOWS A FINE-LINE WEST INTO NERN IL. IF CONVECTION FILLS IN ALONG THE BOUNDARY AND IT REMAINS QUASISTATIONARY OR AT LEAST SLOWLY PROGRESSIVE...LOCALIZED FLOODING WILL BECOME AN INCREASING CONCERN. FOR TIMING OF THE PROGRESSION OF THE COLD FRONT...THE VARIOUS MODELS HAVE CONVERGED INTO GOOD AGREEMENT ON THE PROGRESSION...CROSSING THE RIVER INTO NWRN IL BY ARND 12Z SATURDAY AND STEADILY PROGRESSING EWD TO NRN INDIANA BY LATE AFTERNOON OR EARLY EVENING. THE THUNDERSTORM THREAT SHOULD BE CONFINED TO A ZONE ALONG AND AHEAD OF THE FRONT. FOLLOWING THE FRONTAL PASSAGE...CONDITIONS SHOULD QUICKLY IMPROVE...FOR A TIME...WITH TEMPERATURES DROPPING OFF QUICKLY. TEMPERATURES WILL DROP OFF FROM HIGHS IN THE LOW TO MIDDLE 80S TODAY AND SATURDAY TO LOWS IN THE UPPER 40S TO MIDDLE 50S SUNDAY MORNING AND LOWS IN THE MIDDLE 40S BY MONDAY MORNING. HIGHS FOR SUNDAY AND MONDAY SHOULD BE IN THE LOWER TO MIDDLE 60S. THERE WILL STILL BE SOME CHANCE FOR SOME PCPN SUNDAY AND MONDAY AS THE CENTER OF THE UPPER LOW TRACKS RIGHT OVER NRN IL/IN...BUT ANY PCPN SHOULD GENERALLY BE SCT SHOWERS AND PCPN AMOUNTS GENERALLY LIGHT. FOR THE EXTENDED FORECAST PERIOD...FROM TUESDAY THROUGH FRIDAY...EXPECT A PERIOD OF SLOWLY MODERATING TEMPERATURES WITH LITTLE TO NO CHANCE OF PCPN. FOLLOWING THE PASSAGE OF THE UPPER LOW...A BUILDING UPPER LEVEL RIDGE WILL SLOWLY MOVE OUT OVER THE PLAINS AND MISSISSIPPI VALLEY AS ANOTHER DEEP UPPER LOW DROPS DOWN THE WEST COAST INTO THE DESERT SOUTHWEST. THE AMPLIFYING...BUT SLOWLY PROGRESSIVE PATTERN ALOFT WILL KEEP CONDITIONS DRY WITH ABOVE NORMAL TEMPS OVER THE LOCAL WITH HIGHS IN THE LOWER TO MIDDLE 70S AND LOWS IN THE UPPER 40S TO MIDDLE 50S. KREIN && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 06Z... * LOWERING VISIBILITY AND CIGS INTO IFR CATEGORY INTO OVERNIGHT. * NORTHEAST WINDS BECOMING EAST THEN SOUTHEAST TONIGHT WITH SPEEDS MOST OF TIME BELOW 10 KT. * SMALL CHANCE OF TSRA SAT MORNING GRADUALLY INCREASING INTO MID- AFTERNOON. * THUNDERSTORMS LIKELY 22Z-00Z SOME OF WHICH COULD BE STRONG. BEACHLER //DISCUSSION...UPDATED 06Z... VERY CHALLENGEING AVIATION CONDITIONS ARE IN STORE FOR THE NEXT 24 HOURS ACROSS THE REGION...ESPECIALLY OVER NORTHERN IL/NORTHWEST IN. A STALLED FRONTAL BOUNDARY WAS ORIENTED ACROSS NORTHERN IL...WHICH HAS RESULTED IN LIGHT WINDS TO AT TIMES CALM FOR DPA/ORD/MDW/GYY. IN ADDITION VERY MOIST AIR WAS OVER THESE AIRFIELDS AND HAS RESULTED IN VSBYS BEING REDUCED. IT APPEARS ORD SHOULD ONLY REDUCE TO ARND 3-4SM OVERNIGHT...HOWEVER ELSEWHERE MDW/GYY/DPA/RFD WILL LIKELY SEE VSBYS DOWN BTWN 1/2SM AT RFD/DPA TO 2-3SM AT GYY/MDW. IR IMAGERY INDICATED SOME IFR CIGS WERE DEVELOPING OVER FAR NORTHWEST IL WHICH HAS BROUGHT CIGS DOWN AT RFD...AND IT IS POSSIBLE CIGS COULD DROP TO ARND 200-300FT AGL BEFORE DAYBREKA THEN SLOWLY IMPROVE AFT DAYBREAK. THEN THE FOCUS TURNS TOWARDS CONVECTIVE TIMING/PLACEMENT LATER TODAY. AFTER SUNRISE VSBYS SHUD BE SLOW TO IMPROVE WITH JUST A CIRRUS SHIELD EXPECTED OVERHEAD TO START THE DAY. THE COLD FRONT WILL BE WELL WEST OF THE REGION...HOWEVER STEADILY PIVOTING EAST TOWARDS NORTHERN IL AIRFIELDS. GUIDANCE CONTINUES TO INDICATE WINDS BY MID MORNING WILL BECOME SOUTHERLY ARND 10KT AND OCCASIONAL GUSTS TO THE MID-TEENS ARE LIKELY. CLOUDS WILL THICKEN BY MIDDAY WITH A DECK ARND 3-4KFT AGL. WITH CONSIDERABLE ELEMENTS SUGGESTING CONVECTION WILL BE FIRING ARND 18-19Z...IT IS LIKELY THAT THE BEST CHC FOR CONVECTION WILL BE ARND 19Z-00Z...AND THE BETTER COVERAGE WILL FALL WITHIN A 22-00Z TIMEFRAME. WINDS WILL SLOWLY TURN TO THE 240-260 DEG RANGE FRONTAL PASSAGE...WITH RAIN/THUNDER SLOWLY ENDING AFT 03-06Z SUN. BEACHLER //ORD AND MDW CONFIDENCE...UPDATED 06Z... * HIGH CONFIDENCE IN STABLE/SLIGHTLY LOWERING TREND OF CIG...MEDIUM CONFIDENCE ON VISIBILITY. MEDIUM CONFIDENCE ON HOW LOW CIG AND VISIBILITY WILL FALL. * MEDIUM-HIGH CONFIDENCE IN WIND FORECAST. * MEDIUM CONFIDENCE ON TSRA TIMING OF 21Z-02Z. BEACHLER //OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z... SUNDAY...VFR DURING THE DAY WITH MVFR CIGS AND CHC SHRA DURING THE NIGHT. MONDAY...CHC OF MVFR AND SLT CHC OF SHRA DURING THE MORNING. TUESDAY-THURSDAY...MAINLY VFR. MTF && .MARINE... 341 PM CDT A TROUGH OF LOW PRESSURE AND ASSOCIATED FRONTAL BOUNDARY ARE SITUATED ACROSS THE UPPER MISSISSIPPI VALLEY EAST ACROSS TO THE SOUTHERN GREAT LAKES REGION...WITH THESE FEATURES STEMMING FROM AN AREA OF LOW PRESSURE SITUATED OVER THE CENTRAL PLAINS. ITS THESE FEATURES THAT ARE PROVIDING...AND WILL CONTINUE TO PROVIDE DRASTICALLY VARYING CONDITIONS ACROSS THE ENTIRE LAKE. A LIGHTER WIND FIELD IS CURRENTLY PRESENT OVER THE SOUTHERN PORTIONS OF THE LAKE WHERE THE PRESSURE GRADIENT IS RELAXED...BUT WITH SPEEDS INCREASING TO 15 TO 25 KT FOR THE FAR NORTHERN PORTIONS OF THE LAKE. THIS BOUNDARY WILL LIFT BACK NORTH ACROSS THE LAKE TONIGHT INTO SATURDAY WHILE THIS LOW PRESSURE SYSTEM SLOWLY TRACKS NORTHEAST TOWARDS THE MISSISSIPPI VALLEY. AS THIS OCCURS...EXPECT A GRADUAL TRANSITION TO THE EAST SOUTHEAST WITH SPEEDS INCREASING ACROSS THE ENTIRE LAKE. EXPECT THE HIGHEST SPEEDS OF 30KT TO BE OBSERVED ACROSS THE NORTH...WITH THESE EASTERLY WINDS/SPEEDS LIKELY PERSISTING INTO EARLY SATURDAY NIGHT. EXPECT THIS LOW TO THEN CONTINUE NORTHEAST AND REACH THE CENTRAL GREAT LAKES LATE SATURDAY NIGHT INTO SUNDAY...AND THEN CONTINUE EAST TOWARDS THE EASTERN GREAT LAKES SUNDAY NIGHT INTO MONDAY. AS THIS OCCURS...EXPECT SPEEDS TO DIMINISH WHILE BECOMING MORE SOUTHERLY ON SUNDAY AND THEN WEST/NORTHWEST INTO MONDAY. RODRIGUEZ && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...NONE. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion National Weather Service Lincoln IL 1151 PM CDT Fri Oct 4 2013 .DISCUSSION... ISSUED 850 PM CDT Fri Oct 4 2013 Updated the forecast for tonight to increase the PoPs early in southeast IL for the isolated showers and few rumbles of thunder. Also dropped the PoPs a bit in areas west of the IL River. Radar trends with the convection in Iowa and western Missouri, along with high res model solutions from the HRRR and RAP, indicate that the showers and t-storms may not impact west central IL until close to daybreak. Otherwise, the forecast low temperatures, sky cover and wind are all on track for the rest of tonight. && .AVIATION... ISSUED 1151 PM CDT Fri Oct 4 2013 Latest runs of the high resolution models and the 00z NAM/GFS indicate that the aviation forecast for central IL TAF sites needs few changes from the previous issuance. Still looking for light fog/mist to form toward early morning, although it is looking less likely that a stratus ceiling will develop. Plenty of high and mid clouds from upstream convective debris will move into central and eastern Illinois overnight. Radar trends, as well as the latest HRRR and RAP forecasts, indicating that convective remnants to approach central Illinois shortly after daybreak ahead of the cold front. Plenty of moisture, instability and increasing low/mid level wind shear will be present for t-storms to redevelop in a linear fashion by early afternoon. Maintained the predominant thunderstorm forecast to account for this expected development and movement of a line of storms. The higher resolution models were also indicating that the front will move a bit slower than previously forecast. Thus, the 06z TAFs will extend the thunderstorms a couple of hours from the previous forecast, and also hold off the frontal passage/wind shift until late afternoon- evening. Miller && .PREV DISCUSSION... ISSUED 300 PM CDT Fri Oct 4 2013 The current heat and humidity will be displaced by a chilly Canadian airmass after a strong cold front moves through on Saturday. Severe weather potential will increase as we head into Saturday afternoon, especially if sunshine is able to help destabilized the boundary layer for any portion of the day. A slight risk for severe storms has been outlined by SPC for nearly all of Illinois. The timing of the front remains in question, with a compromise used between the faster NAM/Canadian and the slower GFS/ECMWF. That basically allowed for some consistency with the going forecast. Dry air will be wrapping into the back side of the cold front, but as the occlusion process occurs, bands of moisture will trail the front and allow for a few post frontal showers to linger into Sunday and possibly even Monday. SHORT TERM...Tonight through Sunday night. A Pacific moisture connection will continue to feed into the warm sector across the nations heartland over the next 24-36 hours...as the warm front lingers in N Iowa and S Wisconsin. Localized pockets of energy will tap into that moisture to fuel isolated showers in our SE counties as well as our far NW counties into this evening. Most areas should remain dry this evening, and even overnight. We left a wide area of slight chance pops across the area after midnight, with chance PoPs in the far NW closer to the expected storm track. Tonight and early Saturday, low pressure in the western plains will lift north into eastern South Dakota before stalling during occlusion. It`s eastward progression will pick up speed as a kicker trough enters the northwest coast. The timing of the front will be key in where severe potential is maximized, mainly from the amount of sunshine for low level heating. There may be some isolated severe storms overnight west of our area as the nocturnal jet intensifies ahead of the cold front. The cold front is projected to reach the I-55 corridor by Noon or 1 pm, then slow down and reach the Indiana border mid- evening. Instability params and hodographs are pointing toward damaging winds as the main hazard in our area, with better directional shear and rotating storms farther north near the warm front and track of the low. Hail potential will increase closer to the cold front and moisture pooling and updraft strength intensify. Severe chances will linger into the evening east of I-57, but should become more isolated as the front slows down. We kept likely PoPs east of I-57 Sat eve, and near the Indiana border after midnight. Coverage of storms will likely diminish Sat night as will intensity. Some clearing behind the cold front will low temps drop into the 40s by Sunday morning west of I-55. The cold air will limit highs on Sunday to the upper 50s near GBG and mid 60s near LWV. Scattered rain will be possible across the east and north associated with cold pool-instability showers...as the upper trough lingers just west of IL. Sunday night will be coldest night of the next week, with lows in the low to mid 40s everywhere. LONG TERM...Monday through Friday. The upper vortex may still be over IL on Monday if the GFS and ECMWF verify, which would put showers across IL during the day. We left Mon dry for now, but at least sprinkles may be needed if the next couple of model runs show the slower progression. A warming trend will begin on Tue and continue through Friday. Highs should reach above normal into the mid 70s Thur/Fri. Dry conditions are expected to prevail all week, with comfortable humidity levels. The next chance of rain may hold off until the Sunday Oct 13. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1157 PM CDT Fri Oct 4 2013 .UPDATE: Issued at 950 PM CDT Fri Oct 4 2013 Inherited forecast still looks on track...so made no major changes. Warm advection SHRAS have moved out of SW IL. SHRA/TSTMS along and ahead of the front across ern KS/wrn MO timed to reach the wrn CWA around 9-10Z...if it holds together. Several solutions have moisture convergence along the front weakening significantly overnight across nthrn MO. Going fcst reflects the assumption that precip in one form or another will reach our CWA prior to daybreak. Besides massaging other grids to reflect ongoing trends...existing fcst looks good. 2% && .SHORT TERM: (Through Late Tonight) Issued at 330 PM CDT Fri Oct 4 2013 Diurnal heating of the unseasonably warm and moist air mass has resulted in weak instability across the region this afternoon. However with little impetus, attempts for convective development thus far across far southeast Missouri and southern Illinois have been short-lived. The HRRR continues to indicate potential for spot storms through sunset within the southern CWA so will continue with some slight chance pops until then. Otherwise attention for tonight turns to the strong storm system currently across the Plains region. Anticipating that a squall line will evolve ahead of the attendant cold front from Nebraska into Oklahoma this evening and this will move eastward as the whole system progresses, with a swath of precipitation also developing overnight in the wake of the front in response to frontogenetical forcing and large scale ascent as a short-wave rotates through the base of the progressive upper trof. The main question then is just how far eastward all of this precipitation will get before daybreak Saturday. The consensus of the model guidance is that it may be after 12z before entering the CWA. At this time I didn`t deviate dramatically from the previous forecast with the leading edge just making it into the western CWA, but reduced pops further east. Areas to the east of the main line will still be under the threat of spotty warm advection activity overnight. Glass .LONG TERM: (Saturday through Next Friday) Issued at 300 PM CDT Fri Oct 4 2013 By Saturday morning, surface cold front to be just west of St. Louis metro area. As the occluded surface low, over southeastern SD, associated with it slowly lifts out to the northeast, front to slowly slide through rest of forecast area. Expect activity that initially forms tonight to diminish by mid morning. Then trying to determine when and where activity will refire as atmosphere becomes more unstable by early afternoon is hard to pin down. With front extending from Quincy to just west of St. Louis to near Monett by 18z Saturday, best chances of storms refiring and some severe weather will be over southeast MO and southern IL. This matches well with the day 2 outlook with this area in a slight risk. Another forecast issue will be temperatures on Saturday. Will see a non-diurnal trend as high temps will be reached early in the day then either remain steady or fall during the afternoon hours. Showers and isolated thunderstorms will taper off Saturday evening before coming to an end. However, could see some scattered showers on Sunday, especially during the afternoon hours as wrap around clouds on back side of system moves through with an upper level shortwave. So have added low chance pops over northeast MO/west central IL with silent slight chance pops further south for now as well as increase cloud cover through this period. Lows Saturday night will be in the low 40s to low 50s with highs only rising into the mid 50s to mid 60s on Sunday. Sunday night could be our coldest night depending on how fast the clouds clear out. For now will err on side of caution and keep more clouds over the region with lows in the low to mid 40s. If clouds completely clear out and winds remain light, could see even cooler temps. Beyond that, surface ridge moves off to the east with a slow warming trend through the week. Temperatures to warm back up into the mid to upper 70s by Thursday. Byrd && .AVIATION: (For the 06z TAFs through 06z Saturday Night) Issued at 1125 PM CDT Fri Oct 4 2013 Latest surface analysis shows the cold frontal boundary entering western Missouri. Band of showers and thunderstorms extending north-central Missouri through north-central Oklahoma continues to move northeast. Expect scattered showers and possible thunderstorm to enter Columbia MO area and Quincy IL around 0900 UTC. Scattered showers and a few thunderstorms will enter STL area after 1500 UTC. Cold front expected to move across STL area after 1700 UTC. Post frontal light rain will continue through late afternoon. Specifics for KSTL: Scattered showers and a few thunderstorms will move through STL area after 1500 UTC. Southwest winds of 8 to 10 kts expected during the mid to late morning hours. Brief stronger gusts are possible in the vicinty of thunderstorms. Cold front expected through STL between 1700 and 1800 UTC. Post frontal light rain expected much of the afternoon and ending late afternoon. Westerly wind of 8 to 10 kts expected during the afternoon. RP && .LSX WATCHES/WARNINGS/ADVISORIES: MO...NONE. IL...NONE. && $$ WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
357 AM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 THE MSAS SHOWS THE SFC LOW NEARLY STATIONARY THIS MORNING ACROSS SCNTL SD. THE LOW IS IN THE PROCESS OF DOING A LOOP. THIS AFTERNOON IT WILL DRIFT EAST AT 5 MPH INTO SERN SD AND THIS IS CONSISTENT WITH THE MOTION OF THE 500 MB LOW AT JUST 6 KT. VERY SLOW STORM MOTIONS OF THIS TYPE...5 MPH...OFTEN PRODUCE HIGH WIND EVENTS IN THE CNTL PLAINS. THE GFS...ECM AND RAP SHOW SUSTAINED WINDS INCREASING TO AROUND 40 MPH ACROSS NCNTL NEB THIS AFTERNOON WITH GUSTS TO 58 MPH IN THE RAP AND HRRR MODELS. THE NAM KEEPS THE GUSTS BELOW 58 MPH THIS AFTN. MEANWHILE THE MET GUIDANCE SHOWS NO HIGH WIND EVENT AT ALL WHILE THE MAV GUIDANCE FAVORS SWRN NEB. THE MULTI LAYER WINDS IN THE RAP MODEL FROM H850MB TO H700MB KEEP WINDS AT 60 KTS OR LESS AND THIS IS CONSISTENT WITH A HIGH END WIND ADVISORY WITH A FEW GUSTS TO 58 MPH. THUS THERE IS A SPLIT IN THE MODEL DATA. A HIGH END WIND ADVISORY EVENT WOULD APPEAR TO BE THE MOST LIKELY SOLN INDICATED BY THE MODELS BUT LOCAL STUDIES SUGGEST A HIGH WIND EVENT WOULD UNFOLD THIS AFTERNOON. A WIND ADVISORY WILL CONTINUE TODAY ACROSS ALL AREAS EXCEPT WHERE THE WINTER STORM WARNING IS IN EFFECT. WINTER STORM CONDITIONS ARE LIKELY ONGOING ACROSS NRN SHERIDAN AND WRN CHERRY COUNTIES THIS MORNING. THE RADAR MAY BE OVERSHOOTING THE DENDRITIC LAYER. THE ELLSWORTH NEDOR CAM IS QUIET WHILE THE RUSHVILLE CAM CONTINUES TO SHOW SNOW AND BLOWING SNOW WITH VISIBILITY AROUND 2 MILES OR SO. THE 08Z KIEN OB SHOWS 1/2 MILE VISIBILITY WITH A VERTICAL VISIBILITY OF JUST 500 FEET. THE REST OF THE NEDOR CAMS ARE DARK SO WE WILL HAVE TO WAIT FOR SUNRISE TO GET A BETTER ANALYSIS OF THE SITUATION ACROSS NW NEB. THE WINTER STORM WARNING WILL CONTINUE UNTIL 18Z AS FORECAST. GIVEN THE UPPER LOW HAS STALLED ACROSS THE CNTL PLAINS...THE MODEL CONSENSUS SHOWS WRAPAROUND RAIN AND SNOW TODAY THROUGH SUNDAY MORNING. THE UPPER LEVEL LOW IS EXPECTED TO CONTINUE MOVING SLOWLY EAST SOUTHEAST INTO SRN IOWA BY LATE SUNDAY AFTERNOON. A MULTI MODEL CONSENSUS WAS USED FOR POPS TONIGHT AND SUNDAY. THE RAP MODEL WAS USED EXCLUSIVELY FOR THE TODAY PERIOD. NONE OF THE MODELS ARE SHOWING VERY HEAVY QPF AND SNOW TOTALS OF 2 INCHES OR LESS ARE EXPECTED BASED ON THAT OUTPUT. THERE IS SOME UNCERTAINTY WITH THIS FORECAST AS THE 850 MB MOISTURE TRANSPORT IS STILL QUITE STRONG ACROSS THE NRN PLAINS AND OCCASIONAL LIGHTNING STRIKES ARE STILL SHOWING UP AT 08Z. THE NAM WHICH APPEARS TO HAVE THE BEST HANDLE THE MASSIVE QPF ASSOCIATED WITH THIS STORM GENERALLY KEEPS QPF LESS THAN 0.10 INCHES IN ANY 3 HOUR PERIOD ACROSS NRN NEB. OTHERWISE...HIGHS TODAY RISE INTO THE 30S AND 40S ACCORDING TO A BLEND OF BIAS CORRECTED AND DETERMINISTIC DATA. THE MODELS ARE FORECASTING LOWS IN THE MID 20S TONIGHT ACROSS THE SNOW FIELD ACROSS NWRN NEB WITH LOWER 30S ELSEWHERE. IF THE WRN HALF OF THE FORECAST AREA CLEARS OUT TONIGHT AS INDICATED IN THE MODELS THEN THESE LOWS COULD BE 5 OR MORE DEGREES COLDER. HIGHS SUNDAY RISE INTO THE 40S ACROSS THE SNOW COVERED NORTHWEST WITH 50S AND 60S ELSEWHERE. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 BY SUNDAY NIGHT THE LOW PRESSURE SYSTEM WILL HAVE PUSHED TOWARDS THE MID MISS RVR VALLEY AND THE WRAP AROUND MOISTURE WILL HAVE SHIFTED INTO EASTERN NEB. MEANWHILE AN UPPER LEVEL RIDGE WILL BUILD ACROSS THE WEST...AS THE NEXT TROUGH PUSHES ACROSS NORTHEASTERN PACIFIC OCEAN. MONDAY THROUGH THURSDAY THE PACIFIC TROUGH WILL DIG TOWARDS THE DESERT SOUTHWEST WHILE THE UPPER RIDGE SHIFTS EAST ACROSS THE PLAINS. AT THE SFC HIGH PRESSURE WILL DOMINATE THE PLAINS THROUGH MUCH OF THE WEEK. THUS EXPECT MILD CONDITIONS WITH 70S AND A FEW MID/UPPER 60S ACROSS THE NW ZONES WHERE SOME INFLUENCE FROM THE HEAVY SNOW PACK IS LIKELY TO LIMIT THE HEATING. ONCE THE SNOW MELTS...COULD SEE MORE WIDESPREAD HIGHS INTO THE 70S ACROSS THE NW. WITH THE WARM AIR MASS...EXPECT SEASONALLY WARM LOWS...GENERALLY IN THE 40S SPOTTED WITH A FEW UPPER 30S. LATE THURSDAY INTO FRIDAY THE LOW OVER THE SW WILL BEGIN TO EJECT ONTO THE NORTHERN PLAINS. MODELS IN FAIR AGREEMENT...CONSIDERING 6/7 DAYS OUT...WITH A TRACK OF THE UPPER LOW ACROSS THE CENTRAL ROCKIES AND INTO S DAKOTA. THE MODELS CONTINUE TO TRACK THE LOW TO THE NE...INTO CANADA OVER THE WEEKEND. AS THE LOW PUSHES ONTO THE ROCKIES...GOOD MOISTURE TRANSPORT WITH S WINDS EXPECTED ACROSS THE AREA. POPS ARE NEEDED FOR THURSDAY INTO FRIDAY...HOWEVER PENDING THE TRACK AND THE DRY SLOT...CONCERNED AMOUNTS MAY NOT AMOUNT TO TOO MUCH OVER PART OF THE CWA. THUS WILL HOLD POPS IN THE SLIGHT CHANCE AND LOWER CHANCE CATEGORY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1226 AM CDT SAT OCT 5 2013 WIDESPREAD SNOW IN NORTHWEST NEBRASKA WILL CONTINUE TONIGHT. IN BBW...LIGHT SNOW IS POSSIBLE BUT LITTLE ACCUMULATION IS EXPECTED. FOR LBF...OGA AND IML...THE PROBABILITY OF PRECIPITATION IN EITHER FORM IS LOW. CLEAR SKY IN SOUTHWEST NEBRASKA IS LIKELY TO BECOME OVERCAST AGAIN BY 08Z...BUT THE CEILING IS LIKELY BE ABOVE 3000 FEET AGL. OTHERWISE...WIND WILL CONTINUE TO BE A CONCERN THROUGH AT LEAST SATURDAY AFTERNOON WITH 310-340 AT 24-28G35-38KT IN THE MORNING...INCREASING TO 32-36G40-44KT BY 15Z OR 16Z AS THE STORM SYSTEM MOVES OUT AND A BLAST OF CANADIAN AIR POURS IN BEHIND IT. && .LBF WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NEZ008- 022>027-035>038-056>059-069>071. WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NEZ005. WINTER STORM WARNING UNTIL NOON MDT TODAY FOR NEZ004-094. WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR NEZ006-007-009-010-028-029. && $$ SYNOPSIS...CDC LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1135 PM MDT FRI OCT 4 2013 .AVIATION... 06Z TAF CYCLE VFR CIGS AND VIZ NEXT 24 HRS. WEATHER SYSTEM CORE EJECTING INTO SOUTH DAKOTA WITH BROAD INTENSE CIRCULATION ALOFT PUSHING WESTERLY WINDS ACROSS NEW MEXICO...AND THESE WILL SHIFT RAPIDLY NORTHERLY BY 00Z SAT EVENING. CLOUD COVER AOA BKN/OVC100 ACROSS THE HEART OF NEW MEXICO WILL EJECT RAPIDLY TO THE NORTHEAST THROUGH 15Z SAT MORNING WITH NEXT ROUND OF GUSTS REDEVELOPING FROM 16Z ONWARD ACROSS WESTERN AND CENTRAL PORTIONS OF THE STATE. WIND SPEEDS DROPPING OFF AFTER 03Z SATURDAY EVENING. SHY && .PREV DISCUSSION...315 PM MDT FRI OCT 4 2013... FRONT HAS BEEN HUNG UP JUST NORTH OF THE UNION COUNTY BORDER ALL DAY...ALTHOUGH THE LOW CLOUDS ASSOCIATED WITH IT LAST NIGHT HAVE DISSIPATED OVER SOUTHEAST AND EAST CENTRAL CO. RUC INDICATES THE BOUNDARY TO PLUNGE SWD WITHIN THE NEXT 3 HOURS. IT ALSO INDICATES A LITTLE MORE MOISTURE OVER PARTS OF THE NORTHEAST...AND RESULT HAS BEEN TO UPGRADE SKY COVER TO PARTLY CLOUDY RATHER THAN CLEAR. STILL MODELS NOT SUGGESTING A HUGE UPTICK IN DEW POINTS THERE OVERNIGHT. NORTHERLY WINDS ASSOCIATED WITH THE FRONT AS IT TRACKS THROUGH THE PLAINS TO BE GUSTY BUT NOT QUITE AS STRONG AS INDICATED 24 HOURS AGO. AS FOR FREEZE HIGHLIGHTS...STILL SOME MARGINAL TEMPERATURES FOR PORTIONS OF THE EAST CENTRAL AND RGV AS WELL AS THE SOUTH CENTRAL HIGHLANDS. AND SATURDAY NIGHT TEMPERATURE GUIDANCE IS STILL LEANING TOWARDS SOME WARMING. FORECAST BOUNDARY LAYER WINDS TONIGHT NORTHEAST OVER THE PLAINS BUT FOR SATURDAY NIGHT THE GFS FORECASTS A MORE WLY WIND FLOW IN THE LOWER LEVELS...AS OPPOSED TO THE NAM/S LIGHT AND VRBL TO WEAK NW WINDS. FORECAST SOUNDINGS INDICATE SOME STEEP INVERSIONS OFF THE DECK AT SELECTED POINTS SATURDAY NIGHT BUT OVERALL THE SOUNDINGS EXHIBIT A WARMING TREND. THINK THERE MAY BE SOME POINTS IN SHELTERED AREAS UNAFFECTED BY WIND THAT COULD REACH THE MAGIC 32 OR SLIGHTLY BELOW OUTSIDE OF OUR FORECAST POINTS TONIGHT...SO WENT AHEAD AND UPGRADED REMAINING EAST CENTRAL ZONES IN THE WATCH. ALSO ADDED THE SOUTH CENTRAL HIGHLANDS TO THE WARNING TONIGHT WITH FORECAST LOWS AGAIN HOVERING NEAR THE FREEZING MARK. BASED ON THE ABOVE MODEL DISCUSSION...HAVE HELD OFF ON ISSUING FURTHER FREEZE HIGHLIGHTS FOR SATURDAY NIGHT. WILL WAIT TO SEE WHAT THE GUIDANCE DOES AS WELL AS WHAT MINS TONIGHT DO. WINDS STILL TO TAPER OFF SATURDAY WITH A WARMING TREND SUNDAY THROUGH TUESDAY. MODELS CONTINUE TO FOCUS ON AN UPPER LOW DIGGING INTO THE SW US AROUND THE MID TO LATE WEEK PERIOD NEXT WEEK. WINDS LOOK TO INCREASE TUESDAY AND MORE SO WEDNESDAY WITH TEMPERATURES FALLING THURSDAY/FRIDAY. WE NOW HAVE SOME MEAGER POPS FOR THE NORTH AND WEST DURING THIS PERIOD...BUT MODELS NOT EXACTLY IN AGREEMENT HOW THIS WILL PLAY OUT. .FIRE WEATHER... CURRENT FIRE WEATHER HIGHLIGHTS ARE MARGINAL BUT WILL KEEP THEM RUNNING THROUGH EVENT EXPIRATION. TUCUMCARI IS SHOWING NEAR RED FLAG CONDITIONS WITH GUSTY WINDS AND TEEN HUMIDITY. THE UPPER LOW WHICH IS CURRENTLY OVER THE CENTRAL ROCKIES AND GREAT PLAINS WILL GRADUALLY SHIFT EASTWARD THE REST OF TODAY...TONIGHT INTO SATURDAY. THE SURFACE WIND FLOW WILL GENERALLY RELAX AS A RESULT ALTHOUGH A BACK DOOR COLD FRONT WILL PUSH ACROSS THE EASTERN PLAINS TONIGHT AND INCREASE WINDS FOR A TIME. A CHILLY NIGHT IS IN STORE WITH FREEZING TO NEAR FREEZING TEMPERATURES EXPECTED ACROSS THE MAJORITY OF THE FIRE WEATHER FORECAST AREA. A HARD FREEZE WILL BE FELT ACROSS THE NORTHERN AND WESTERN MOUNTAINS AND INCLUDE SOME LOWLAND SITES AS WELL. HIGH PRESSURE WILL BE IN CONTROL DURING THE WEEKEND. THE SURFACE WIND FLOW WILL BE MUCH MORE RELAXED ALTHOUGH LOOK FOR SOME NORTHERLY BREEZES ACROSS SOME WESTERN AND CENTRAL AREAS SATURDAY AFTERNOON. THE FLOW ALOFT WILL BE MUCH WEAKER SO MAINLY SURFACE DRIVEN. FAIRLY LIGHT WINDS FOR SUNDAY WITH JUST A FEW BREEZES ALONG INTERSTATE 25 BETWEEN LAS VEGAS TO RATON. MIXING HEIGHTS WILL BE ON THE LOWER SIDE THANKS TO POST COLD FRONTAL INVERSION EFFECTS. THUS VENTILATION RATES WILL BE LOWER. VENTILATION WILL BE THE POOREST ON SUNDAY. EXPECTING A STRONG LOW LEVEL RADIATION INVERSION TO DEVELOP SATURDAY NIGHT. THIS WILL BE ACCOMPANIED BY ADDITIONAL FREEZING TEMPERATURES WITHIN BASINS AND VALLEYS. HIGH TEMPERATURES WILL BE WELL BELOW NORMAL SATURDAY AND BE AROUND 5 TO 10 DEGREES BELOW NORMAL SUNDAY AFTERNOON. HUMIDITY VALUES WILL BE NEAR SEASONABLE LEVELS ON SATURDAY BUT LOWER ON SUNDAY WITH LOTS OF MINIMUM VALUES IN THE TEENS. A MID LEVEL DRY INTRUSION PLUS A WARM UP WILL BE THE CATALYST FOR LOWER HUMIDITY VALUES SUNDAY. WEATHER MODELS REMAIN PERSISTENT WITH DEPICTING RIDGING ON MONDAY AND THEN BREAKING DOWN OR SHIFTING EASTWARD ON TUESDAY. TEMPERATURES WOULD CONTINUE TO WARM WHILE THE UPPER FLOW TURNS MORE SOUTHWESTERLY ON TUESDAY. DRY CONDITIONS WOULD CONTINUE. VENTILATION RATES WILL REMAIN ON THE LOWER SIDE MONDAY ALTHOUGH IMPROVE IN A FEW AREAS COMPARED TO SUNDAY/S READINGS. TRANSPORT WINDS WILL INCREASE TUESDAY SO THE VENTILATION WILL IMPROVE SIGNIFICANTLY THEN. NEAR TO ABOVE NORMAL TEMPERATURES EXPECTED EARLY NEXT WEEK AND SURFACE HUMIDITY WILL REMAIN ON THE LOWER SIDE. CURRENTLY HAVE SOME LOCALIZED CRITICAL FIRE WEATHER GROWTH CONDITIONS DEPICTED WITHIN OUR GRIDDED FORECAST TUESDAY AFTERNOON ACROSS THE NORTHEAST SO WILL BE MONITORING THAT TREND. THE LATEST LONG RANGE MODELS CONTINUE TO SHOW A BREEZY TO WINDY PATTERN WEDNESDAY THROUGH FRIDAY AS ANOTHER PACIFIC TROUGH CROSSES OVER THE INTERMOUNTAIN WEST. IT STILL APPEARS TO BE A DRY TROUGH PASSAGE FOR THE FORECAST AREA. THUS...CANT RULE OUT SOME CRITICAL FIRE WEATHER AREAS...MOST LIKELY FAVORING THE EAST...WHERE TEMPERATURES WOULD BE ABOVE NORMAL FOR THE LONGEST. COOLING EXPECTED ACROSS THE WEST ON THURSDAY AND SPREAD ACROSS THE ENTIRE AREA ON FRIDAY. THIS AIR MASS APPEARS TO BE LESS CHILLY COMPARED TO THE CURRENT ONE. VENTILATION WOULD BE QUITE HIGH WEDNESDAY AND THURSDAY AND PROBABLY LOWER SOME ON FRIDAY. CONFIDENCE IS AT LEAST MODERATE FOR THIS SCENARIO. 50 && .ABQ WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING UNTIL 9 AM MDT SATURDAY FOR THE FOLLOWING ZONES... NMZ518-519-524-530>534. && $$ 33
AREA FORECAST DISCUSSION
NWS RALEIGH NC
314 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE OVER THE REGION WILL MOVE SLOWLY EAST OFFSHORE THE CAROLINA COAST TONIGHT AND SUNDAY. A COLD FRONT WILL APPROACH THE MOUNTAINS FROM THE WEST SUNDAY NIGHT...THEN TRACK EASTWARD THROUGH THE CAROLINAS ON MONDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 940 PM FRIDAY... LITTLE CHANGE TO THE OVERNIGHT FORECAST NEEDED AS HIGH PRESSURE REMAINS PERSISTENT OVER THE CAROLINAS. SKIES HAVE CLEARED AND WINDS. DEWPOINTS HAVE RECOVERED ANOTHER 2 TO 4 DEGREES SINCE 24 HOURS AGO...MAINLY ACROSS THE SOUTH... AND DEWPOINT DEPRESSIONS ARE ALREADY LESS THAN 5 DEGREES AT MANY OBSERVING SITES. RH CROSS SECTIONS FAVOR SOUTHERN AREAS FOR FOG...AND THE RECENT HRRR RUNS SUPPORT THIS. LOWS MOSTLY IN THE 60-63 RANGE. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... AS OF 255 PM FRIDAY... SATURDAY AND SATURDAY NIGHT...HIGH PRESSURE PERSISTS...WITH MID-LEVEL HEIGHTS ACTUALLY RISING FOR A TIME SATURDAY BEFORE BEGINNING TO FALL AGAIN SATURDAY NIGHT. BUFR SOUNDINGS FROM BOTH THE NAM AND THE GFS SUGGEST A COUPLE OF DEGREES OR SO OF WARMING ALOFT AROUND 500MB SATURDAY...WITH SOME 850MB MOISTURE AVAILABLE ONCE AGAIN SUGGESTIVE OF SOME DIURNAL CUMULUS WITH MIXING SATURDAY MORNING INTO THE AFTERNOON. SUBSIDENCE CONTINUES TO DOMINATE...AND K INDICES ACTUALLY FALL SOMEWHAT ON THE GFS DURING THE DAY SATURDAY. ANOTHER DRY DAY ANTICIPATED WITH LIGHT WINDS EARLY INCREASING A TOUCH...UNDER 10KT...AND SHOWING A SOUTHERLY COMPONENT BEFORE AGAIN DIMINISHING TO FAIRLY LIGHT SOUTHERLY SATURDAY NIGHT. 1000-850MB THICKNESSES SUPPORT HIGHS AROUND THE MOS GUIDANCE...MANY UPPER 80S AND A FEW READINGS AT 90. AVAILABLE LOW-LEVEL MOISTURE SUPPORTS A GREATER PROBABILITY OF AREAS OF FOG ACROSS CENTRAL NORTH CAROLINA LATE SATURDAY NIGHT INTO SUNDAY MORNING...AND HAVE AGAIN CONTINUED THIS IN THE GRIDDED AND WORDED FORECASTS. OVERNIGHT LOWS SATURDAY NIGHT MAINLY LOWER 60S. -DJF SUNDAY...WINDS ALOFT WILL BACK TO SOUTHWESTERLY AS THE MID-UPPER RIDGE AXIS SHIFTS EAST AND OFFSHORE...WHICH WILL PROMOTE A GRADUAL INCREASE IN MID TO ESPECIALLY HIGH LEVEL MOISTURE THROUGHOUT THE DAY SUNDAY. THE COMBINATION OF THE INCREASING CLOUDS AND THE EASTWARD DEPARTURE OF THE RIDGE ALOFT WILL LIKELY RESULT IN TEMPERATURES UP TO A FEW DEGREES COOLER THAN THOSE OF SAT - OR WITHIN A COUPLE OF DEGREES EITHER SIDE OF 85. THE TIGHTENING MSL PRESSURE GRADIENT IN RETURN FLOW WILL ALSO PROMOTE THE DEVELOPMENT OF A SOUTHERLY BREEZE THAT WILL PEAK IN THE 10-15 KT RANGE OVER THE WESTERN PIEDMONT ACCORDING TO MIXED LAYER WINDS DEPICTED BY BUFR FORECAST SOUNDINGS. DESPITE THE INCREASING MAINLY HIGH CLOUDS...PRECIPITATION CHANCES WILL REMAIN RELATIVELY LOW. WILL ACCORDINGLY TRIM INHERITED PRECIPITATION CHANCES AND CONFINE A SLIGHT CHANCE TO ROUGHLY THE SOUTHERN HALF OF THE CWFA...TO ACCOUNT FOR THE PROPAGATION OF SHOWERS THAT FORM OWING TO ONSHORE FLOW/FRICTIONAL CONVERGENCE AND WEAK HEIGHT FALLS ALOFT...IN A WEAKLY INHIBITED AND UNSTABLE ENVIRONMENT ALONG AND INVOF COASTAL AREAS. -MWS && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... THE LATEST INFORMATION FROM THE NHC CONCERNING "KAREN" CONTINUES TO DOWNGRADE THE TROPICAL SYSTEM. IT HAS BEEN DESCRIBED AS ALREADY BEING `DECAPITATED" BY ONE FORECASTER - DUE TO STRONGER WINDS ALOFT. THEREFORE... THE CONFIDENCE OF WHETHER ANY REMNANTS OF `KAREN" WILL BE LEFT TO BRING INDIRECT IMPACTS (RAIN, SEVERE THREAT) FOR CENTRAL NC BY EARLY NEXT WEEK HAS LOWERED. ON A MORE CONFIDENT NOTE... A MID/UPPER LEVEL TROUGH IS FORECAST TO BE APPROACHING THE APPALACHIANS MONDAY... THEN SWING ACROSS OUR REGION TUE AND TUE NIGHT. THE MAIN UPPER DYNAMICS ARE FORECAST TO PUSH FROM THE MIDWEST TO THE GREAT LAKES. HOWEVER... MOISTURE IS EXPECTED TO SURGE NORTHWARD ALONG THE EASTERN SEABOARD BRINGING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE COLD FRONT. IF THE REMNANT LOW PRESSURE OF `KAREN` TRACKS NE INTO NC AS SOME OF THE MODELS STILL SUGGEST... THERE CAN STILL BE ENHANCED RAINFALL FOR 12-24 HOURS. OTHERWISE... THIS WOULD BE A TYPICAL RAINFALL EVENT ASSOCIATED WITH A MID-LATITUDE TROUGH EARLY NEXT WEEK. ONCE THE TROUGH PASSES... CLEARING AND COOLER CONDITIONS ARE EXPECTED MID THROUGH LATE WEEK. LOWS 50-55. HIGHS 70-75. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... AS OF 300 AM SATURDAY... 24-HR TAF PERIOD: FOG IS EXPECTED TO DEVELOP EARLY THIS MORNING IN ASSOCIATION WITH CLEAR SKIES...CALM WINDS...AND A SEASONABLY MOIST AIRMASS. FOG WILL BE MOST LIKELY AT THE FAY/RWI TERMINALS WHERE IFR-VLIFR VISBYS ARE EXPECTED IN THE 08-12Z TIME FRAME...FOLLOWED BY RDU WHERE MVFR/IFR VISBYS WILL BE POSSIBLE BETWEEN 08-12Z...AND FINALLY THE INT/GSO TERMINALS WHERE MVFR VISBYS WILL BE POSSIBLE BETWEEN 09-12Z. FOG WILL LIFT AND SCATTER OUT TO VFR BETWEEN 12-14Z...WITH VFR CONDITIONS AND LIGHT WINDS THE REMAINDER OF THE TAF PERIOD. LOOKING AHEAD: ASIDE FROM A POTENTIAL FOR FOG OR SUB-VFR CEILINGS BETWEEN 08-12Z SUNDAY MORNING...VFR CONDS ARE EXPECTED TO PREVAIL DURING THE DAY SUNDAY WITH CEILINGS SOMEWHAT LOWER THAN PREVIOUS DAYS (3500-4500 FT AGL) IN ASSOC/W A STRENGTHENING SOUTHERLY RETURN FLOW AS HIGH PRESSURE MOVES OFFSHORE. EXPECT AN INCREASING CHANCE FOR MVFR/IFR CEILINGS AT ALL TERMINALS IN ADVANCE OF A COLD FRONT PROGRESSING SLOWLY EAST INTO THE SOUTHERN APPALACHIANS SUNDAY NIGHT...ALONG WITH AN INCREASING CHANCE FOR RAIN AT THE INT/GSO TERMINALS BETWEEN 06-12Z MONDAY MORNING. EXPECT WIDESPREAD SHOWERS/THUNDERSTORMS DURING THE DAY MONDAY AS THE COLD FRONT TRACKS EAST INTO THE CAROLINAS. UNCERTAINTY IN THE FCST INCREASES THEREAFTER... HOWEVER...IT IS POSSIBLE THAT RAIN AND SUB-VFR CONDITIONS PERSIST MONDAY NIGHT INTO TUESDAY. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...SMITH SHORT TERM...DJF/MWS LONG TERM...BADGETT AVIATION...VINCENT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO RESIDE OVER THE REGION THROUGH SUNDAY. INCREASING MOISTURE AHEAD OF BOTH A COLD FRONT...AND TROPICAL STORM KAREN...WILL SPREAD INTO THE REGION FOR THE START OF THE NEXT WORK WEEK. && .NEAR TERM /THROUGH TONIGHT/... AS OF 940 PM FRIDAY... LITTLE CHANGE TO THE OVERNIGHT FORECAST NEEDED AS HIGH PRESSURE REMAINS PERSISTENT OVER THE CAROLINAS. SKIES HAVE CLEARED AND WINDS. DEWPOINTS HAVE RECOVERED ANOTHER 2 TO 4 DEGREES SINCE 24 HOURS AGO...MAINLY ACROSS THE SOUTH... AND DEWPOINT DEPRESSIONS ARE ALREADY LESS THAN 5 DEGREES AT MANY OBSERVING SITES. RH CROSS SECTIONS FAVOR SOUTHERN AREAS FOR FOG...AND THE RECENT HRRR RUNS SUPPORT THIS. LOWS MOSTLY IN THE 60-63 RANGE. && .SHORT TERM /SATURDAY THROUGH SUNDAY/... AS OF 255 PM FRIDAY... SATURDAY AND SATURDAY NIGHT...HIGH PRESSURE PERSISTS...WITH MID-LEVEL HEIGHTS ACTUALLY RISING FOR A TIME SATURDAY BEFORE BEGINNING TO FALL AGAIN SATURDAY NIGHT. BUFR SOUNDINGS FROM BOTH THE NAM AND THE GFS SUGGEST A COUPLE OF DEGREES OR SO OF WARMING ALOFT AROUND 500MB SATURDAY...WITH SOME 850MB MOISTURE AVAILABLE ONCE AGAIN SUGGESTIVE OF SOME DIURNAL CUMULUS WITH MIXING SATURDAY MORNING INTO THE AFTERNOON. SUBSIDENCE CONTINUES TO DOMINATE...AND K INDICES ACTUALLY FALL SOMEWHAT ON THE GFS DURING THE DAY SATURDAY. ANOTHER DRY DAY ANTICIPATED WITH LIGHT WINDS EARLY INCREASING A TOUCH...UNDER 10KT...AND SHOWING A SOUTHERLY COMPONENT BEFORE AGAIN DIMINISHING TO FAIRLY LIGHT SOUTHERLY SATURDAY NIGHT. 1000-850MB THICKNESSES SUPPORT HIGHS AROUND THE MOS GUIDANCE...MANY UPPER 80S AND A FEW READINGS AT 90. AVAILABLE LOW-LEVEL MOISTURE SUPPORTS A GREATER PROBABILITY OF AREAS OF FOG ACROSS CENTRAL NORTH CAROLINA LATE SATURDAY NIGHT INTO SUNDAY MORNING...AND HAVE AGAIN CONTINUED THIS IN THE GRIDDED AND WORDED FORECASTS. OVERNIGHT LOWS SATURDAY NIGHT MAINLY LOWER 60S. -DJF SUNDAY...WINDS ALOFT WILL BACK TO SOUTHWESTERLY AS THE MID-UPPER RIDGE AXIS SHIFTS EAST AND OFFSHORE...WHICH WILL PROMOTE A GRADUAL INCREASE IN MID TO ESPECIALLY HIGH LEVEL MOISTURE THROUGHOUT THE DAY SUNDAY. THE COMBINATION OF THE INCREASING CLOUDS AND THE EASTWARD DEPARTURE OF THE RIDGE ALOFT WILL LIKELY RESULT IN TEMPERATURES UP TO A FEW DEGREES COOLER THAN THOSE OF SAT - OR WITHIN A COUPLE OF DEGREES EITHER SIDE OF 85. THE TIGHTENING MSL PRESSURE GRADIENT IN RETURN FLOW WILL ALSO PROMOTE THE DEVELOPMENT OF A SOUTHERLY BREEZE THAT WILL PEAK IN THE 10-15 KT RANGE OVER THE WESTERN PIEDMONT ACCORDING TO MIXED LAYER WINDS DEPICTED BY BUFR FORECAST SOUNDINGS. DESPITE THE INCREASING MAINLY HIGH CLOUDS...PRECIPITATION CHANCES WILL REMAIN RELATIVELY LOW. WILL ACCORDINGLY TRIM INHERITED PRECIPITATION CHANCES AND CONFINE A SLIGHT CHANCE TO ROUGHLY THE SOUTHERN HALF OF THE CWFA...TO ACCOUNT FOR THE PROPAGATION OF SHOWERS THAT FORM OWING TO ONSHORE FLOW/FRICTIONAL CONVERGENCE AND WEAK HEIGHT FALLS ALOFT...IN A WEAKLY INHIBITED AND UNSTABLE ENVIRONMENT ALONG AND INVOF COASTAL AREAS. -MWS && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... THE LATEST INFORMATION FROM THE NHC CONCERNING "KAREN" CONTINUES TO DOWNGRADE THE TROPICAL SYSTEM. IT HAS BEEN DESCRIBED AS ALREADY BEING `DECAPITATED" BY ONE FORECASTER - DUE TO STRONGER WINDS ALOFT. THEREFORE... THE CONFIDENCE OF WHETHER ANY REMNANTS OF `KAREN" WILL BE LEFT TO BRING INDIRECT IMPACTS (RAIN, SEVERE THREAT) FOR CENTRAL NC BY EARLY NEXT WEEK HAS LOWERED. ON A MORE CONFIDENT NOTE... A MID/UPPER LEVEL TROUGH IS FORECAST TO BE APPROACHING THE APPALACHIANS MONDAY... THEN SWING ACROSS OUR REGION TUE AND TUE NIGHT. THE MAIN UPPER DYNAMICS ARE FORECAST TO PUSH FROM THE MIDWEST TO THE GREAT LAKES. HOWEVER... MOISTURE IS EXPECTED TO SURGE NORTHWARD ALONG THE EASTERN SEABOARD BRINGING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE COLD FRONT. IF THE REMNANT LOW PRESSURE OF `KAREN` TRACKS NE INTO NC AS SOME OF THE MODELS STILL SUGGEST... THERE CAN STILL BE ENHANCED RAINFALL FOR 12-24 HOURS. OTHERWISE... THIS WOULD BE A TYPICAL RAINFALL EVENT ASSOCIATED WITH A MID-LATITUDE TROUGH EARLY NEXT WEEK. ONCE THE TROUGH PASSES... CLEARING AND COOLER CONDITIONS ARE EXPECTED MID THROUGH LATE WEEK. HOWEVER... THE 00Z/05 OCTOBER OPERATIONAL EC SUGGESTS THE FRONT MAY HANG UP OVER SC/GA WED... WITH THE MID/UPPER TROUGH HANGING BACK OVER THE SE STATES INTO THURS. WE WILL INCORPORATE A LOW PERCENTAGE OF THIS SOLUTION INTO THE FORECAST AT THE CURRENT TIME. THIS WOULD YIELD PARTLY CLOUDY SKIES IN THE EAST AND SOUTH LATE TUE AND WED. LOWS 50-55. HIGHS 70-75. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 745 PM FRIDAY... AREAS OF FOG ARE EXPECTED DEVELOP LATE TONIGHT BETWEEN 06 TO 12Z......WITH THE HIGHEST PROBABILITY AND CORRESPONDINGLY LOWER VISIBILITIES EXPECTED IN THE EAST AT KRWI AND KFAY. BEYOND THE 18Z VALID TAF PERIOD...AREAS OF FOG WILL BE POSSIBLE AGAIN EARLY SUNDAY MORNING...OTHERWISE EXPECT PREDOMINATELY VFR CONDITIONS THROUGH THE WEEKEND. MOISTURE ASSOCIATED WITH REMNANTS OF TS KAREN WILL SPREAD INTO THE AREA LATE SUNDAY NIGHT AND INTO MONDAY. SUB-VFR CONDITIONS WILL BE POSSIBLE AGAIN LATE SUNDAY NIGHT AND MONDAY MORNING WITH WIDESPREAD SHOWERS AND STORMS MONDAY AFTERNOON THROUGH MONDAY NIGHT WITH CORRESPONDING AREAS OF SUB-VFR CONDITIONS. WIDESPREAD VFR CONDITIONS ARE LIKELY TO RETURN BY TUESDAY AFTERNOON AS A COLD FRONT PUSHES EAST AND OFFSHORE. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DJF NEAR TERM...SMITH SHORT TERM...DJF/MWS LONG TERM...BADGETT AVIATION...CBL
AREA FORECAST DISCUSSION
NWS TULSA OK
1141 PM CDT FRI OCT 4 2013 .AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM. LEAD EDGE OF SHOWES/THUNDERSTORMS IS CURRENTLY MOVING INTO NE OKLAHOMA...AND WILL IMPACT THE KBVO/KTUL AND KRVS TAF SITES THROUGH ABOUT 09-10Z. THIS ACTIVITY SHOULD APPROACH SE OKLAHOMA AND NW ARKANSAS LATER TONIGHT TOWARD 10-12Z. OVERALL THUNDERSTORM INTENSITY WILL CONTINUE TO DECREASE. EXPECT AREAS OF MVFR CONDITIONS IN THE STRONGER STORMS. && .PREV DISCUSSION... /ISSUED 910 PM CDT FRI OCT 4 2013/ ..UPDATE... DISCUSSION... THUNDERSTORMS CONTINUED TO RIDE ALONG THE INITIAL WIND SHIFT OF THE COLD FRONT THIS EVENING FROM SOUTHWEST OKLAHOMA TO JUST WEST OF OSAGE COUNTY AS OF 9 PM THIS EVENING. THE DRIER AIR REMAINED FURTHER WEST ACROSS NORTHWEST OKLAHOMA. THESE THUNDERSTORMS WILL PUSH INTO THE CWA OVER THE NEXT HOUR AS THE FRONT CONTINUES TO PUSH EAST SOUTHEASTWARD. WITH THE LOSS OF DAYTIME HEATING THE CAP HAS BEGUN TO STRENGHTEN ACROSS THE CWA...HOWEVER DEEP LAYER SHEAR NEAR AND JUST BEHIND THE FRONT WILL ALLOW FOR THE POTENTIAL FOR SOME STORMS TO BECOME STRONG TO SEVERE. LARGE HAIL AND STRONG WINDS CONTINUE TO BE THE MAIN THREATS WITH THIS ACTIVITY. GREATEST POTENTIAL FOR ANY SEVERE STORMS LOOKS TO BE MAINLY NORTHWEST OF INTERSTATE 44 OVER THE NEXT FEW HOURS. THE SEVERE THUNDERSTORM WATCH FOR OSAGE AND PAWNEE COUNTIES REMAINS IN EFFECT UNTIL 3Z. LATEST RUNS OF THE HRRR AND THE LOCAL IN-HOUSE MODEL INDICATE THAT THUNDERSTORMS COULD BE NEAR EAST CENTRAL OKLAHOMA BY 06Z AND INTO SOUTHEAST OKLAHOMA AND NORTHWEST ARKANSAS BY 9Z. INSTABILITY ACROSS THE REST OF THE CWA SHOULD WEAKEN OVERNIGHT AS THE CAP CONTINUES TO STRENGHTEN...THOUGH AN ISOLATED STRONG TO SEVERE STORM COULD BE POSSIBLE. GUSTY NORTHWESTERLY WINDS IN THE 20 TO 30 MPH RANGE HAVE BEEN OBSERVED BEHIND THE FRONT WITHIN THE DRIER/COOLER AIR AND WILL CONTINUE TO FILTER INTO THE REGION OVERNIGHT. TEMPERATURES BY EARLY SATURDAY MORNING LOOK BE AROUND 50 TO LOWER 50S NEAR THE KANSAS BORDER TO THE 60S FOR FAR SOUTHEAST OKLAHOMA AND WEST CENTRAL ARKANSAS. EVENING UPDATE WILL BE TO ADJUST POPS/WX/SKY GRIDS BASED ON LATEST TRENDS AND TIMING...WHILE THE REST OF THE FORECAST SEEMS TO BE HANDLING WELL AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... TUL 54 64 47 68 / 90 20 10 0 FSM 70 73 46 68 / 80 70 10 0 MLC 59 60 44 70 / 90 60 10 0 BVO 52 65 43 66 / 80 20 10 0 FYV 63 65 42 63 / 80 80 10 10 BYV 66 68 44 62 / 80 80 10 10 MKO 57 59 45 68 / 90 60 10 0 MIO 53 61 43 64 / 90 50 10 10 F10 55 60 46 69 / 90 40 10 0 HHW 71 73 46 72 / 80 50 10 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ AVIATION...18
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
456 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY AND TONIGHT. A LOW PRESSURE SYSTEM TRACKING FROM THE CENTRAL PLAINS TO THE GREAT LAKES WILL PUSH A STRONG COLD FRONT THROUGH THE AREA ON MONDAY. THE LOW AND COLD FRONT WILL MOVE OFFSHORE BY TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 345 AM EDT SATURDAY... SURFACE HIGH PRESSURE AND A 500 MB RIDGE WILL REMAIN OVER THE CENTRAL AND SOUTHERN APPALACHIANS TODAY AND TONIGHT. LOCAL WRF AS WELL AS HRRR AND LATEST RAP GUIDANCE SUGGEST THERE IS STILL A LOW CHANCE OF SHOWERS THIS AFTERNOON...MAINLY NORTH OF I-64. ASIDE FROM THE WEST TO SOUTHWEST UPSLOPE WINDS...LITTLE IN THE WAY OF SHORT WAVES TO HELP TRIGGER ANY PRECIPITATION. DEEP SOUTHWEST WINDS THIS AFTERNOON...EVEN THOUGH WIND SPEEDS WILL NOT BE VERY STRONG...WILL PROVIDE SOME DOWNSLOPNIG AND COMPRESSION. COMBINED WITH 850 MB TEMPERATURES OF +16 TO +18...MAXIMUM TEMPERATURES WILL AGAIN BE WELL ABOVE NORMAL. EXPECTING SIMILAR TEMPERATURES COMPARED TO FRIDAY...AND POSSIBLY A DEGREE OR TWO HIGH AS LONG AS THERE IS NOT CLOUD COVER. ANY SCATTERED TO BROKEN STRATOCUMULUS THAT DEVELOPS TODAY WILL DISSIPATE THIS EVENING. USED A BLEND OF BIAS CORRECTED MAV/MET GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 453 AM EDT SATURDAY... MODELS REMAINING CONSISTENT WITH MOVING A COLD FRONT AND ASSOCIATED SHOWERS INTO THE OHIO VALLEY ON SUNDAY. MODELS HAVE SLOWED DOWN THE FRONTS MOVEMENT INTO THE AREA SUNDAY NIGHT AND ACROSS THE REGION MONDAY/MONDAY NIGHT. THE SLOWER PROGRESSION OF THE FRONT IS DUE TO UPPER LEVEL FORCING BECOMING DETACHED FROM THE LOW LEVEL BOUNDARY. TROPICAL STORM KAREN OR REMNANTS OF...MAY ALSO PLAYING A PART IN SLOWING THE FRONT DOWN TO A CRAWL AS IT CROSSES OVER THE AREA. BASED ON THE 00Z MODEL TRENDS...LOWERED POPS INTO SUNDAY EVENING. MEASURABLE RAIN BEGINS TO TRACK ACROSS THE SOUTHWEST EARLY MONDAY MORNING...THEN SPREADS ACROSS THE REST OF THE MOUNTAINS AROUND SUNRISE. RAIN CHANCES INCREASE EAST OF THE BLUE RIDGE TOWARD THE AFTERNOON AND CONTINUES INTO THE EVENING. WITH A COLD FRONT INTERACTING WITH TROPICAL MOISTURE...IT WAS A NO BRAINER TO INCREASE POPS TO 100 PERCENT MONDAY. WITH THE FRONT BEING SLOWER...ALSO INCREASED POPS MONDAY EVENING...TRENDING DOWN TUESDAY MORNING AS THE FRONT TRACKS EAST. WITH SHOWERS NOT DUE TO MOVE ACROSS THE PIEDMONT UNTIL THE AFTERNOON...THERE MAY BE ENOUGH INSTABILITIES TO GENERATE A RUMBLE OF THUNDER. IF ENOUGH INSTABILITIES IS PRESENT WHEN THE 850 JET PASSES OVERHEAD...A STORM OR TWO MAY PRODUCE STRONG WINDS. FOR THE MOST PART...THIS WILL BE A HYDRO EVENT. PWATS ON MONDAY APPROACH 2 INCHES WHICH IS CLOSE TO BEING 2 STANDARD DEVIATIONS ABOVE NORMAL. RAINFALL AMOUNTS FROM SUNDAY NIGHT INTO MONDAY EVENING SHOULD RANGE FROM 1 TO 2 INCHES. WITH THE RECENT DRY SPELL...THE FORECAST AREA SHOULD NOT SEE ANY WIDESPREAD WATER PROBLEMS. LOCALIZE FLOODING IS NOT OUT OF THE QUESTION IN POOR DRAINAGE AREAS...ESPECIALLY IF HIGH RAINFALL RATES OR TRAINING OF STORMS PERSIST OVER AN AREA FOR SEVERAL HOURS. THE UPPER LEVEL RIDGE THAT BROUGHT WARMTH TO THE AREA ON SATURDAY WILL BEGIN TO SLIDE OFF THE SOUTHEAST COAST ON SUNDAY. WITH THE FRONT REMAINING WEST OF THE AREA FOR MOST OF SUNDAY...WARMER THAN NORMAL TEMPERATURES WILL AGAIN COVER THE REGION. SUNDAY TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S ACROSS THE WEST TO MID TO UPPER 80S IN THE EAST. A DRAMATIC COOL DOWN COMES MONDAY WITH THE RAIN. FORECASTED HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE WEST TO LOWER 70S ACROSS THE PIEDMONT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 1215 PM EDT FRIDAY... FORECAST EARLY IN THE PERIOD CENTERS AROUND THE FRONT/REMNANTS OF KAREN AND THE UPPER TROUGH MOVING ACROSS THE GREAT LAKES/NORTHEAST/MID ATLANTIC. THE LATEST GFS (12Z) CONTINUES TO BE SLOWER...AND IS ACTUALLY SLOWER THAN THE 06Z RUN IN MOVING THE FRONT OUT...WITH A STRONGER UPPER LOW...BUT IS FURTHER EAST WITH KAREN. PER NHC/WPC...WILL BE LEANING TOWARD THE 00Z ECMWF AND THE PREVIOUS FORECAST. THERE WILL STILL BE LINGERING SHOWERS ACROSS THE PIEDMONT TUESDAY AND NOT OUT OF THE QUESTION THAT STRONG SUBSIDENCE BEHIND THE DEPARTING TROPICAL SYSTEM MAY START TO DRY THINGS OUT FASTER. FOR MID TO LATE WEEK...THE FORECAST MAINTAINS A CHALLENGE IN TERMS OF SFC HIGH PRESSURE WEDGING SOUTH INTO OUR AREA...WHILE A RESIDUAL UPPER TROUGH LINGERS OVER THE SOUTHEAST. QUESTION WILL BE WHERE DEEPER MOISTURE RESIDES. WITH THE ECMWF THINK MOST OF THE CLOUD COVER WILL BE HUGGING OUR SOUTHEAST CWA WITH MORE RESIDING ACROSS THE SOUTHEAST...WHILE THE WESTERN CWA SEES MORE SUN DURING THE DAY. TEMPERATURES GIVEN A LIGHT NE-E FLOW WILL BE CLOSER TO NORMAL...WITH THE THREAT OF RAIN BEING LESS THAN 10 PERCENT. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... AS OF 130 AM EDT SATURDAY... TEMPERATURE/DEW POINT SPREAD WAS ALREADY CLOSE TO ZERO AT KBCB/KLYH AND KDAN. HIGH CONFIDENCE OF IFR TO LIFR FOG ALONG AREA RIVERS EARLY THIS MORNING WHICH WILL RESULT IN LIFR VISIBILITIES AT KBCB AND KLWB. ONCE FOG MIXES OUT IN THE MORNING THE REST OF THE DAY WILL BE VFR. TIMING OF HOW FAST FOG LIFTS SHOULD BE BETWEEN 8AM AND 10AM. MID AND HIGH LEVEL CLOUDS WILL ARRIVE SUNDAY THOUGH AS THE COLD FRONT ENTERS THE OHIO VALLEY. OUR NEXT CHANCE FOR WIDESPREAD AND PROLONGED SUB-VFR CONDITIONS WILL COME SUNDAY NIGHT INTO MONDAY WHEN A COLD FRONT APPROACHES FROM THE WEST...AND WHAT IS LEFT OF TROPICAL CYCLONE KAREN RIDES NORTH THROUGH OR NEAR OUR REGION IN ADVANCE OF IT. THIS WOULD ALLOW A TREND TOWARD DECREASING CEILING HEIGHTS AND INCREASED COVERAGE OF RAIN. VISIBILITIES WOULD TREND LOWER AS WELL...ESPECIALLY SUNDAY INTO MONDAY AS PRECIPITATION INTENSIFIES AND FOG POTENTIAL INCREASES. RAIN ENDS MONDAY NIGHT BUT THERE STILL MAY BE RESTRICTIONS IN CEILING AND VISIBILITY AS PRECIP COULD STILL BE HEAVY ACROSS THE VA/NC PIEDMONT WITH POTENTIALLY SOME FOG ACROSS SE WEST VA. A DRIER PATTERN IS EXPECTED TUESDAY AND WEDNESDAY WITH MORNING FOG. && .CLIMATE... RECORD HIGH TEMPS FOR SATURDAY. ROANOKE 98/1941 LYNCHBURG 96/1941 DANVILLE 98/1951 BLACKSBURG 86/1954 BLUEFIELD 85/2007 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...RCS LONG TERM...JH/WP AVIATION...AMS/KK/KM CLIMATE...RCS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
414 AM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 413 AM CDT SAT OCT 5 2013 MOST EFFORT THIS FORECAST SHIFT WAS PUT TOWARD GETTING THE NEXT 24 HOURS AS ACCURATE AS POSSIBLE. SCREAMING MESSAGE IS THE SLOWER EASTWARD PROGRESSION OF THE FRONT AND INSTABILITY...MAKING FOR A BIT HIGHER SEVERE WEATHER CHANCE IN WI TODAY. WATER VAPOR SHOWING THE MONSTER LOW THAT BROUGHT 25-45 INCHES OF SNOW TO SD OVER CENTRAL SD AT 08Z AND NEARLY STATIONARY. OCCLUDED FRONT CURRENTLY POSITIONED FROM KRWF TO KCCY...WHERE THE TRIPLE POINT IS LOCATED. THE WARM FRONT EXTENDS EAST FROM NEAR KCCY TO THE DELLS IN WI...WITH THE SURFACE COLD FRONT RUNNING SOUTH FROM KCCY. THIS WARM FRONT IS THE LEADING EDGE OF THE HIGHER DEWPOINT AIR...MIDDLE 60S...AND THE ENERGY FOR THIS AFTERNOONS STORMS. THE OVERNIGHT CONVECTION HAS NOW PASSED OFF TO THE EAST...AND WITH IT THE FLASH FLOOD THREAT. EVALUATING THE 04.00Z MODEL GUIDANCE...THE TREND IS SLOWER WITH THE NORTHEAST PROGRESSION OF THE OCCLUDED/COLD FRONT. THIS ALLOWS MORE OF THE FORECAST AREA IN WI TO BE PRE-FRONTAL AND IN THE WARM SECTOR FOR A HIGHER PROBABILITY OF SEVERE WEATHER. AS THE DAY PROGRESSES...QVECTOR CONVERGENCE WILL INCREASE AS A SHORTWAVE TROUGH IN COLORADO ROTATES AROUND THE LARGER SD TROUGH AND BEGINS ITS EASTWARD PROGRESSION. AS THE FORCING BEGINS TO INCREASE...NEAR/POST FRONTAL SHOWERS WILL LIKELY DEVELOP MUCH LIKE SEEN ON RADAR ALONG I-35 EARLY THIS MORNING. ALSO...BETTER UPPER LEVEL FORCING WILL BEGIN TO WORK TOWARD THE WARM SECTOR AND WORK WITH 0-2KM THETA-E CONVERGENCE ALONG THE FRONT. INSTABILITY IN THE WARM SECTOR WILL HIGHLY DEPEND ON THE EXTENT OF THE SHOWERS AND CLOUDS OVER WI...HOWEVER BECAUSE THE DEWPOINTS ARE ALREADY MIDDLE 60S...AT LEAST MARGINAL INSTABILITY WILL BE PRESENT BY 18Z. MUCAPES AROUND 1000-1500 J/KG LOOK TO BE A GOOD ESTIMATE ON AFTERNOON CAPE...POSSIBLY HIGHER WITH MORE CLOUD BREAKS. WIND SHEAR LOOKS TO INCREASE TODAY BUT RIGHT ON THE COLD/OCCLUDED FRONTAL BOUNDARY...TO MAKE IT A MARGINAL SUPERCELL DAY WITH MULTICELLS ALSO PRESENT. THE 05.06Z NAM AND 05.07Z RAP BOTH SUGGEST NEAR 40 KTS OF 0-6KM SHEAR...CERTAINLY ENOUGH FOR SUPERCELLS. THE 05.07Z RAP MIXES ALL THE PRE-FRONTAL SURFACE WINDS TO SOUTHERLY. THE 05.06Z NAM AND LATEST HRRR RUNS ARE VERY AGREEABLE THAT THE WARM FRONT WILL SHIFT NORTH TO ABOUT BLACK RIVER FALLS WI TODAY...VERY CLOSE TO THE SPC DAY 1 NORTHERN EXTENT OF THE SLIGHT RISK. EASTERLY FLOW IS FOUND NORTH OF THE WARM FRONT...WHICH EXTENDS TO THE EAST TOWARD KGRB...SO A GOOD CONVERGENT BOUNDARY. WHILE TORNADO PROBABILITIES DONT LOOK HIGH...THE TRIPLE POINT AREA AND ALONG THAT WARM FRONT THIS AFTERNOON WILL BE A FOCAL POINT. OTHERWISE...DAMAGING WIND SEGMENTS OR LARGE HAIL ARE THE MAIN THREATS FROM THE STORMS IN WI. NORTH OF THE WARM FRONT...LOW-LEVEL INVERTED CONDITIONS AND ELEVATED STORMS ARE FAVORED...HEAVY RAIN IS THE MAIN THREAT...WITH AN ISOLATED HAIL STORM POSSIBLE. THE FRONT SHOULD SHIFT EAST OF THE FORECAST AREA BY EARLY EVENING WITH STRONG DEWPOINT DECREASES. THUS...THE MAIN SEVERE WEATHER THREAT LOOKS TO BE ABOUT 1 PM TO 5 PM. BY TONIGHT...THE NE AND EASTERNMOST FORECAST AREA MAY STILL HAVE SOME RAIN REMAINING. HAVE SLOWED THAT SLIGHTLY FROM THE PREVIOUS FORECAST. A DECREASING TREND OCCURS THROUGH THE EVENING AS WEATHER SHIFTS EAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 413 AM CDT SAT OCT 5 2013 THE LATEST MODEL CONSENSUS IS TO NOW KEEP THE DEFORMATION ASSOCIATED WITH THE CYCLONIC MOIST FLOW WRAPPING AROUND THE LOW TO THE WEST-NORTHWEST ON SATURDAY. THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE LOW WHICH IS A BIT FURTHER SOUTH IN THE LATEST GUIDANCE. IN ANY CASE...CHANGES WERE MADE TO SUNDAY TO TRY AND DRY IT OUT WITH THE RAIN SHOWERS JUST WEST OF THE AREA. ALTHOUGH THE CONSENSUS OF THE MODELS IS TO BRING THAT BAND INTO THE FORECAST AREA FOR MONDAY NOW...THE LATEST 05.00Z ECMWF IS MUCH MORE PROGRESSIVE AND RAPIDLY SHIFTS THE SHOWERS EAST. HAVE A SMALL CHANCE OF SHOWERS TO ADDRESS THAT SITUATION. THE REMAINDER OF THE PERIOD IS DOMINATED BY DRY WEATHER UNDER LARGER SCALE RIDGING AND ABOVE NORMAL TEMPERATURES. && .HYDROLOGY... ISSUED AT 413 AM CDT SAT OCT 5 2013 CONCERNING THE FLASH FLOOD WATCH...WITH CURRENT CONVECTION EAST OF THE AREA...MAIN THREAT HAS DIMINISHED. AS AFTERNOON CONVECTION INCREASES...IT SHOULD BE AFFECTING AREAS THAT HAVE HAD LESS RAIN OVERALL THAN THOSE WEST OF THE MISS RIVER. AREAS EAST OF THE MISS RIVER CAN TAKE ANOTHER 1-2 INCHES...ESPECIALLY SWRN WI. THERE IS A SMALL PROBABILITY OF LOCALIZED FLASH FLOODING TODAY IN THE CENTRAL WI CORRIDOR IN THE PRE-FRONTAL AIR MASS WHICH WILL STILL HAVE 1.25 TO 1.75 INCH PRECIPITABLE WATER VALUES. RAIN RATES ARE EXPECTED TO BE HIGH...PROBABLY 2 TO 3 INCH PER HOUR SHOULD CAPE DEVELOP AS FORECAST. THE SLOW MOVEMENT OF THE FRONT DOES GIVE SOME CONCERN FOR FLOODING SO WILL ISSUE ANOTHER HYDROLOGICAL DISCUSSION FOR THAT AREA AND CANCEL THE FLASH FLOOD WATCH. THERE ARE SOME RIVER RESPONSES CURRENTLY OCCURRING. MONITORING THE ROOT RIVER BASIN AND THE UPPER IOWA RIVERS BOTH HAVE RESPONSES. ALSO THE WHITEWATER RIVER MIDDLE FORK THAT RUNS THROUGH WHITEWATER STATE PARK IS RISING. AT THIS TIME THESE WILL APPROACH FLOOD STAGE BUT IT IS BELIEVED THEY WILL NOT REACH IT. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1140 PM CDT FRI OCT 4 2013 BACK EDGE OF THE CONVECTION IS MAKING STEADY EASTWARD PROGRESS AND STILL EXPECT IT TO CLEAR BOTH TAF SITES BY 08Z. UNTIL IT DOES...IFR CONDITIONS WILL REMAIN POSSIBLE AS LOCALLY HEAVY RAIN COULD DROP THE VISIBILITY AND POSSIBLY THE CEILINGS DOWN. ONCE THE RAIN MOVES THROUGH...A TEMPORARY DRY SLOT WILL MOVE INTO TO ALLOW FOR A PERIOD OF PRIMARILY VFR CONDITIONS. AS THE MAIN SURFACE LOW STARTS TO TRACK TOWARD THE AREA SATURDAY MORNING...EXPECT TO SEE THE OCCLUDED FRONT LIFT INTO AND THROUGH THE AREA. THE 05.00Z NAM SUGGESTS THAT AS THIS HAPPENS...THE LOW LEVEL MOISTURE TRANSPORT WILL INCREASE WITH THE NOSE OF THIS INTO THE AREA LONG THE OCCLUDED FRONT. THE MAIN UPPER LEVEL SYSTEM WILL ALSO BE APPROACHING TO PROVIDE ADDITIONAL FORCING AND EXPECTING TO SEE ANOTHER AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOP BY MID MORNING AND CONTINUE INTO THE EARLY AFTERNOON. CONSIDERABLE UNCERTAINTY ON WHAT THE CEILINGS WILL DO WITH THE OCCLUDED FRONT BUT MOST GUIDANCE SUGGEST A RETURN TO MVFR BEFORE DRIER STARTS TO SPREAD IN FROM THE WEST TO ALLOW THE RAIN TO END AND VFR CONDITIONS TO RETURN. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BAUMGARDT LONG TERM...BAUMGARDT AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CDT FRI OCT 4 2013 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 330 PM CDT FRI OCT 4 2013 FORECAST CONCERNS ARE ON SEVERE THUNDERSTORM POTENTIAL TONIGHT AND THE POSSIBILITY OF A FEW SEVERE STORMS IN CENTRAL WISCONSIN LATE SATURDAY MORNING INTO EARLY SATURDAY AFTERNOON. LATEST SURFACE OBSERVATIONS SHOWED SURFACE LOW PRESSURE OVER CENTRAL NEBRASKA...LIFTING NORTHEAST. A WARM FRONT EXTENDED SOUTHEAST THROUGH SOUTHWEST AND CENTRAL IOWA. THE FRONT WILL LIFT NORTH LATE THIS AFTERNOON INTO THIS EVENING AND BE THE FOCUS FOR STRONG TO SEVERE THUNDERSTORM DEVELOPMENT AS A POTENT UPPER LOW PUSHES EAST ACROSS THE NEBRASKA PANHANDLE. THE WARM FRONT IS EXPECTED TO LIFT NORTH INTO NORTHERN IOWA AND PERHAPS EXTREME SOUTHWEST WISCONSIN THIS EVENING. STRONG 850 MB MOISTURE TRANSPORT FOCUSES INTO THE FRONT THIS EVENING...LEADING TO SHOWERS AND THUNDERSTORMS DEVELOPING OVER NORTHEAST IOWA...SOUTHEAST MINNESOTA AND PORTIONS OF SOUTHWEST WISCONSIN. MEANWHILE THE SURFACE LOW WILL LIFT NORTH INTO SOUTHEAST SOUTH DAKOTA AS THE LOW OCCLUDES. A TRIPLE POINT LIFTS NORTHEAST FROM NORTHEAST IOWA INTO SOUTH CENTRAL MINNESOTA LATE IN THE EVENING. THE 04.17 HRRR SHOWS ISOLATED STRONG STORMS DEVELOPING ALONG THE FRONT. STORMS ALSO DEVELOP OVER WESTERN IOWA EARLY THIS EVENING CLOSER TO THE OCCLUSION. THESE STORMS WILL LIKELY BE SUPERCELLS...CAPABLE OF PRODUCING LARGE HAIL...DAMAGING WINDS AND ISOLATED TORNADOES. THE STORMS FURTHER TO THE NORTH OVER THE FORECAST AREA...SHOULD BE NORTH OF THE WARM FRONT AND ELEVATED IN NATURE. 1-7 KM BULK SHEAR VALUES HOVER RIGHT AROUND 30 KTS DURING THE EVENING HOURS SO CANNOT RULE OUT ISOLATED SEVERE STORMS CAPABLE OF PRODUCING LARGE HAIL...HEAVY RAINFALL...AND POSSIBLY DAMAGING WINDS. THE HIGHEST CHANCES FOR SEVERE WEATHER WILL BE OVER NORTHEAST IOWA AND SOUTHEAST MINNESOTA...WEST OF HIGHWAY 52. A FEW OF THESE STRONGER STORMS COULD MAINTAIN INTENSITY INTO PORTIONS OF WESTERN WISCONSIN BUT SHOULD THEN WEAKEN AS THEY MOVE EAST...BUT STILL CAPABLE OF PRODUCING HEAVY RAINFALL. THE 850 MB MOISTURE TRANSPORT GRADUALLY SHIFTS EAST INTO WESTERN WISCONSIN OVERNIGHT WITH WIDESPREAD SHOWERS AND STORMS PERSISTING. THE MAIN THREAT FROM THE STORMS SHOULD GRADUALLY SHIFT TOWARDS HEAVY RAIN LATE IN THE NIGHT. A COLD FRONT THEN PUSHES EAST ACROSS THE REGION EARLY SATURDAY MORNING AND SHOULD BE POSITIONED RIGHT ALONG THE MISSISSIPPI RIVER BY THE MID TO LATE MORNING HOURS. IF ENOUGH INSTABILITY CAN BUILD AHEAD OF THE FRONT...THERE IS THE POSSIBILITY OF SEEING A FEW STRONG TO SEVERE STORMS OVER CENTRAL WISCONSIN. THE MAIN HAZARDS FROM THESE STORMS WOULD BE DAMAGING WINDS. SHOWERS AND STORMS WILL END FROM WEST TO EAST SATURDAY AFTERNOON AS A DRY SLOT PUSHES INTO THE REGION. TEMPERATURES SHOULD FALL ACROSS THE AREA SATURDAY AFTERNOON IN THE WAKE OF THE COLD FRONT. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 330 PM CDT FRI OCT 4 2013 MOST OF THE FORECAST AREA WILL REMAIN IN THE DRY SLOT SATURDAY NIGHT...WITH THE EXCEPTION OF NORTH CENTRAL WISCONSIN WHERE A FEW SHOWERS MAY LINGER. PLAN ON A COOLER NIGHT WITH LOWS FALLING INTO THE 40S. A FEW 30S CANNOT BE RULED OUT OVER CENTRAL WISCONSIN. THE UPPER LOW MOVES INTO INTO WESTERN IOWA ON SUNDAY AND EVENTUALLY INTO WESTERN ILLINOIS SUNDAY NIGHT. SHOWERS WRAPPING AROUND THE LOW LOOK TO MOVE INTO THE REGION SUNDAY AND WILL LIKELY CONTINUE INTO SUNDAY NIGHT AS THE LOW PROGRESSES EAST. THE LOW THEN LOOKS TO MOVE INTO THE EASTERN GREAT LAKES LATE ON TUESDAY WITH HIGH PRESSURE BUILDING INTO THE AREA IN ITS WAKE. HIGH PRESSURE THEN BUILDS OVER THE AREA WEDNESDAY INTO THURSDAY WITH DRY AND QUIET WEATHER EXPECTED...OUTSIDE OF THE POSSIBILITY OF OF SOME EARLY MORNING VALLEY FOG. A TROUGH IS EXPECTED TO DIG INTO THE SOUTHWEST CONUS LATE IN THE WEEK. SOUTHWEST FLOW LOOKS TO DEVELOP OVER THE UPPER MISSISSIPPI RIVER VALLEY LATE FRIDAY INTO SATURDAY. FORECAST MODELS SHOWS THE TROUGH EJECTING INTO THE CENTRAL AND NORTHERN PLAINS...WILL HAVE TO KEEP A VERY CLOSE EYE ON THIS SYSTEM OVER THE NEXT SEVERAL MODEL RUNS. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1140 PM CDT FRI OCT 4 2013 BACK EDGE OF THE CONVECTION IS MAKING STEADY EASTWARD PROGRESS AND STILL EXPECT IT TO CLEAR BOTH TAF SITES BY 08Z. UNTIL IT DOES...IFR CONDITIONS WILL REMAIN POSSIBLE AS LOCALLY HEAVY RAIN COULD DROP THE VISIBILITY AND POSSIBLY THE CEILINGS DOWN. ONCE THE RAIN MOVES THROUGH...A TEMPORARY DRY SLOT WILL MOVE INTO TO ALLOW FOR A PERIOD OF PRIMARILY VFR CONDITIONS. AS THE MAIN SURFACE LOW STARTS TO TRACK TOWARD THE AREA SATURDAY MORNING...EXPECT TO SEE THE OCCLUDED FRONT LIFT INTO AND THROUGH THE AREA. THE 05.00Z NAM SUGGESTS THAT AS THIS HAPPENS...THE LOW LEVEL MOISTURE TRANSPORT WILL INCREASE WITH THE NOSE OF THIS INTO THE AREA LONG THE OCCLUDED FRONT. THE MAIN UPPER LEVEL SYSTEM WILL ALSO BE APPROACHING TO PROVIDE ADDITIONAL FORCING AND EXPECTING TO SEE ANOTHER AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOP BY MID MORNING AND CONTINUE INTO THE EARLY AFTERNOON. CONSIDERABLE UNCERTAINTY ON WHAT THE CEILINGS WILL DO WITH THE OCCLUDED FRONT BUT MOST GUIDANCE SUGGEST A RETURN TO MVFR BEFORE DRIER STARTS TO SPREAD IN FROM THE WEST TO ALLOW THE RAIN TO END AND VFR CONDITIONS TO RETURN. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR WIZ017-029-032>034- 041>044-053. MN...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR MNZ079-086>088- 094>096. IA...FLASH FLOOD WATCH UNTIL 7 AM CDT SATURDAY FOR IAZ008>011-018-019. && $$ SHORT TERM...WETENKAMP LONG TERM...WETENKAMP AVIATION...04
AREA FORECAST DISCUSSION
NWS ALBANY NY
641 AM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONTAL BOUNDARY OVER THE NEW YORK PENNSYLVANIA BORDER...WILL KEEP CLOUDS ALONG WITH AN ISOLATED TO SCATTERED THREAT OF SHOWERS FOR THE FIRST HALF OF THIS WEEKEND. AS THE BOUNDARY MOVES NORTH OF THE CAPITAL REGION TONIGHT INTO SUNDAY...MORE WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS WILL INCREASE ACROSS THE REGION...ALONG WITH HIGHER HUMIDITY LEVELS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 630 AM EDT...A FEW LIGHT SHOWERS PER THE LATEST 88D SCANS WERE TRACKING ACROSS THE DACKS WITH A MORE CONCENTRATED AREA OF CONVECTION IN THE BUFFALO VICINITY. LATEST HRRR REFLECTIVITY FORECASTS SUGGESTS THIS UPSTREAM BAND OF CONVECTION SHOULD WEAKEN AS IT APPROACHES A MORE STABLE DOWNSTREAM AIR MASS. OTHERWISE...THE FRONTAL BOUNDARY HAS MOVED LITTLE WITH THE BETTER PROGRESS ACROSS SOUTHWEST NY STATE. NO OTHER CHANGES AT THIS TIME. PREV DISC... QUASI-STATIONARY BOUNDARY WAS SITUATED ALONG THE NY/PA BORDER. REGIONAL RADAR MOSAIC REVEALS WIDELY SCATTERED SHOWERS ACROSS CENTRAL AND WESTERN NY WITH MORE ROBUST CONVECTION ACROSS LOWER MICHIGAN AND APPROACHING LOWER ONTARIO PROVENCE. H2O VAPOR LOOP DOES HINT AT A WEAK SHORT WAVE EMBEDDED WITHIN THE WESTERLY FLOW NORTH OF THIS FRONTAL BOUNDARY THAT IS THE LIKELY CULPRIT FOR THE AFOREMENTIONED DEEPER CONVECTION UPSTREAM. LATEST HOURLY RUN OF THE RUC13/HRRR AND 4KM SPC WRF MODELS SUGGEST THIS UPSTREAM SHOULD WEAKEN AS IT OUTRUNS THE LOW LEVEL JET /AOA 20KTS/ AND ELEVATED INSTABILITY. MEANWHILE...SURFACE HIGH SITUATED NORTH OF THE GREAT LAKES REGION CONTINUES TO EXTEND ITS INFLUENCE EAST AND SOUTHWARD WHICH WILL LIKELY KEEP THIS FRONTAL BOUNDARY FROM MOVING FURTHER NORTH THROUGH THE DAY. WITH THAT SAID...WE REMAIN ON THE COOLER SIDE OF THE BOUNDARY WITH CONSIDERABLE CLOUD COVER AND THE CHANCE /SLIGHT-CHC FOR SOME SHOWER ACTIVITY. WE WILL SHADE ON THE COOLER SIDE OF THE GUIDANCE...CLOSER TO THE MET MOS VALUES AND HOURLY LAMP/LAV. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... 00Z NCEP MODEL SUITE AND INTERNATIONAL GUIDANCE HAVE RESULTED IN A LARGER SHIFT TOWARD A SLOWER MORE AMPLIFIED PATTERN. THE RESULT IS A SLOWER TIMING OF THE WARM FRONTAL PASSAGE TO BE FOLLOWED BY THE COLD FRONT LATE MONDAY OR MONDAY NIGHT. TONIGHT...THE LOW LEVEL JET UPSTREAM WILL INCREASE IN EARNEST AS PRECIPITATION/CONVECTION UNFOLD. THE BEST WARM ADVECTION AND ISENTROPIC LIFT IS EXPECTED TO OCCUR OVER WESTERN AND CENTRAL NY. PER THE CORFIDI VECTORS AND THICKNESS...THIS ACTIVITY WILL LIKELY SPREAD INTO THE WESTERN ZONES AND THE DACKS THROUGH THE OVERNIGHT AND GRADUALLY SPREAD ACROSS THE REMAINDER OF THE CWA. WE WILL GRADUALLY INCREASE POPS FROM WEST TO EAST AND KEEP TEMPERATURES A BIT STEADY AS THE WARMER AIR BEGINS TO ADVECT NORTHWARD. THROUGH SUNDAY...THE PROGRESS OF THIS WARM FRONT WILL BE INTERESTING TO WATCH AS THE SURFACE HIGH /1024MB/ NORTH OF THE GREAT LAKES MIGRATES ACROSS NORTHERN NEW ENGLAND AND KEEPING THE LOWER LEVEL AGEOSTROPHIC FLOW ACROSS THE HUDSON RIVER VALLEY AND POINTS EAST. ONCE AGAIN CONSIDERABLE CLOUD COVER ALONG WITH SHOWERS AS WE WILL FAVOR A MOS BLEND OF THE NAM/GFS. SUNDAY NIGHT...TRENDS ARE FAVORING FOR A MID LEVEL DRY SLOT TO ADVECT INTO THE REGION WHICH SHOULD REDUCE COVERAGE OF PRECIP BUT KEEP THE LOW LEVEL MOISTURE IN PLACE. IN FACT...CROSS SECTIONS REVEAL AMPLE WIND SHEAR AT OR JUST ABOVE THE LOW LEVEL MOISTURE THAT POCKETS OF DRIZZLE MAY DEVELOP. TEMPERATURES SHOULD BE A LITTLE MILDER. MONDAY...A FAIRLY DEEP UPR LOW ACROSS THE MID WEST AND ITS ASSOCIATED SURFACE LOW/COLD FRONT ARE EXPECTED TO SLOW THE FORWARD PROGRESSION OF THIS SYSTEM. THIS WILL LIKELY PLACE OUR REGION WELL WITHIN THE WARM SECTOR...HOWEVER...MARINE INFLUENCE COMPONENT REMAINS TO BE SEEN AS THE LOW LEVEL JET WILL BE INCREASING FROM THE SSW. FOR NOW WE WILL FAVOR A BLENDED APPROACH TO THE MAV/MET MOS. AS FOR PRECIP CHANCES...WE WILL REDUCE THE POPS FROM THE PREVIOUS FORECAST DUE TO THE SLOWER ARRIVAL TIME BUT STILL KEEP THE MENTION OF THUNDER. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... A DYNAMIC STORM SYSTEM WILL BE APPROACHING AT THE START OF THE EXTENDED PERIOD. A LARGE CLOSED LOW WILL BE MOVING ACROSS THE OHIO VALLEY/EASTERN GREAT LAKES WITH A STRONG COLD FRONT AT THE SURFACE. AHEAD OF THIS BOUNDARY...A STRONG SOUTHERLY LOW LEVEL JET WILL TRANSPORT PLENTY OF MOISTURE /SOME OF WHICH WAS ASSOCIATED WITH THE REMAINS OF TC KAREN...WHICH WILL ALREADY HAVE BEEN ABSORBED INTO THE FRONTAL ZONE ACROSS THE SOUTHEAST/ TOWARDS THE REGION. THE 00Z GEFS SHOWS PWAT VALUES 2-3 STD ABOVE NORMAL ACROSS THE REGION FOR MON NIGHT INTO TUESDAY. THE MODELS CONTINUE TO SHOW PLENTY OF DISAGREEMENT WITH THE TIMING OF THIS FRONT. THE ECMWF DOESN/T CLOSE THE UPPER LOW OFF...AND A RESULT...IS MUCH QUICKER WITH THE BOUNDARY. WE WILL FAVOR THE SLOWER 00Z GFS SOLUTION...WHICH IS ALSO BETTER IN LINE WITH THE 00Z GGEM AND 00Z GEFS. AS A RESULT...MONDAY NIGHT MAY START OFF VERY MILD AND MUGGY WITH TEMPS IN THE 60S AND ONLY SCT RAIN SHOWERS...AND STEADY PRECIP MAY NOT ARRIVE UNTIL VERY LATE AT NIGHT OR UNTIL DURING THE DAY TUESDAY. TEMPS WILL STILL BE MILD ON TUESDAY...WITH UPPER 60S TO LOW 70S ACROSS THE REGION. A LINE OF SHOWERS ALONG/JUST AHEAD OF THE FRONT LOOK TO MOVE THROUGH SOMETIME ON TUESDAY. THE RAIN MAY BRIEFLY FALL HEAVY AT TIMES. WE WILL INCLUDE A SLIGHT CHC FOR THUNDER...BUT MEAGER INSTABILITY LEVELS SHOULD KEEP THUNDER FROM BEING MORE WIDESPREAD. MOST AREAS WILL SEE AROUND AN INCH OF RAINFALL...WHICH IS ACTUALLY NEEDED DUE TO THE RECENT DRY STRETCH. FLOODING ISSUES OUTSIDE LOW LYING/URBAN/POOR DRAINAGE AREAS AREN/T ANTICIPATED DUE TO THE DRY ANTECEDENT CONDITIONS AND HIGH FFG. BEHIND THE FRONT...STEADY RAIN WILL MOVE OFF TO THE EAST AND END...AND TEMPS AND HUMIDITY LEVELS WILL START TO FALL OFF. THE THREAT FOR PRECIP WON/T BE ENTIRELY GONE...AS THE UPPER LOW LOOKS TO PASS OVER THE REGION...SO THE THREAT FOR RAIN SHOWERS WILL CONTINUE FOR WED/THURS...MAINLY ACROSS THE HIGH TERRAIN AND NORTHERN AREAS. TEMPS WILL BE COOLER FOR TUES NIGHT BEHIND THE FRONT WITH 40S AND 50S. DAYTIME TEMPS ON WED/THURS WILL BE A BIT COOLER THAN RECENT DAYS...BUT STILL ABOVE NORMAL...WITH MID 60S FOR VALLEY AREAS. OVERNIGHT LOWS WED AND THURS NIGHTS WILL MAINLY BE IN THE 40S. ONCE THE UPPER LOW EXITS...A STRONG RIDGE WILL ESTABLISH ITSELF ALONG THE EASTERN SEABOARD...ALLOWING FOR EVEN MILDER AIR TO RETURN TO THE REGION. AN EXTENDED PERIOD OF DRY WEATHER LOOKS TO BE IN PLACE FROM THURSDAY NIGHT INTO MUCH OF THE WEEKEND...WITH ABOVE NORMAL WARMTH. DAYTIME TEMPS MAY RETURN TO NEAR 70 FOR FRI/SAT...WHICH IS ABOUT 10 DEGREES ABOVE NORMAL FOR MID OCT. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... FLYING CONDITIONS LOOK TO STAY MVFR FOR KALB/KGFL FOR MUCH OF THE MORNING WITH LOTS OF LINGERING LOW CLOUDS AS A STALLED OUT FRONTAL BOUNDARY WILL CONTINUE TO BE DRAPED OVER THE REGION. KPOU/KPSF MAY CONTINUE TO SEE A FEW MORE HOURS OF IFR CIGS BEFORE CIGS RISE TO MVFR CONDITIONS BY MID TO LATE MORNING. THERE MAY BE A BRIEF PERIOD OF IMPROVEMENT DURING AFTERNOON WITH VFR CONDITIONS POSSIBLE AT KGFL/KALB/KPOU. SOME SCT RAIN SHOWERS MAY AFFECT THE REGION WITH LIGHT AND VARIABLE SFC WINDS DURING THE AFTN HOURS AS WELL. ALL SITES LOOK TO BE BACK IN MVFR CONDITIONS FOR LOW CIGS BY THIS EVENING WITH CALM WINDS AND POSSIBLE RAIN SHOWERS AS THE SLOW MOVING FRONTAL BOUNDARY REMAINS NEARLY STATIONARY OVER THE AREA. IFR CONDITIONS FOR LOW CIGS MAY BE POSSIBLE LATE TONIGHT AS WELL...BUT CONFIDENCE IN THIS IS NOT HIGH ENOUGH TO INCLUDE IN THE TAFS AT THIS TIME. OUTLOOK... SUNDAY NIGHT-MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA. MONDAY NIGHT-TUESDAY: HIGH OPERATIONAL IMPACT. LIKELY SHRA...TSRA. TUESDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA. WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX. && .FIRE WEATHER... LOW LEVEL MOISTURE WILL REMAIN RATHER HIGH ALONG WITH THE INCREASE THREAT FOR MORE SHOWERS. WINDS WILL BE RATHER LIGHT WITH A TENDENCY FROM THE NORTHERLY DIRECTION THROUGH TONIGHT AT SPEEDS LESS THAN 10 MPH. FIRE WEATHER CONCERNS WILL BE AT A MINIMUM. && .HYDROLOGY... NO WIDESPREAD PROBLEMS ARE EXPECTED ON THE MAIN STEM RIVERS OVER THE NEXT 5 DAYS. FLOWS CONTINUE AT NORMAL TO BELOW NORMAL LEVELS FOR EARLY OCTOBER. RAINFALL FORECASTS WILL RANGE FROM ONE QUARTER TO ONE HALF OF AN INCH BASIN AVERAGE NORTH AND WEST OF THE CAPITAL DISTRICT WITH ONE TENTH TO ONE QUARTER OF AN INCH FROM THE CAPITAL DISTRICT TO POINTS EAST AND SOUTH. THESE VALUES WILL BE SLIGHTLY HIGHER ACROSS THE HIGHER TERRAIN BUT LIKELY HAVE LITTLE IMPACT TO THE RIVERS WITH SLIGHT RISES EXPECTED. MAIN CHALLENGE WILL BE THE INCREASING MOISTURE PROFILES HEADING INTO MONDAY. MOISTURE FROM WHAT IS LEFT OF TS KAREN MAY BECOME ABSORBED WITHIN THE FRONTAL SYSTEM AS IT APPROACHES LATE MONDAY. RAINFALL AMOUNTS UP TO AND OVER ONE INCH ARE POSSIBLE. WITHIN BANK RIVER RISES ARE EXPECTED WITH POSSIBLE ISSUES FROM FALLEN LEAFS BLOCKING STORM DRAINS TO RESULT IN PONDING WATER. PLEASE REFER TO THE LATEST TROPICAL GUIDANCE FROM THE NATIONAL HURRICANE CENTER. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. MA...NONE. VT...NONE. && $$ SYNOPSIS...BGM NEAR TERM...BGM SHORT TERM...BGM LONG TERM...FRUGIS AVIATION...FRUGIS FIRE WEATHER...BGM/WASULA HYDROLOGY...BGM/WASULA FOR THE LATEST UPDATES...PLEASE VISIT OUR WEBPAGE AT WWW.WEATHER.GOV/ALBANY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1147 AM EDT SAT OCT 5 2013 .SYNOPSIS... ISSUED AT 342 AM EDT SAT OCT 5 2013 A LARGE LOW PRESSURE SYSTEM WILL BRING INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH EARLY NEXT WEEK. THIS LOW PRESSURE SYSTEM WILL ALSO SEND A COLD FRONT THROUGH THE AREA WITH TEMPERATURES RETURNING TO NEAR NORMAL VALUES AFTER HIGHS IN THE LOW 80S AGAIN TODAY. && .UPDATE... ISSUED AT 1125 AM EDT SAT OCT 5 2013 A COUPLE OF SMALL SCALE EMBEDDED WAVES IN SOUTHWEST UPPER FLOW HAVE RESULTED IN CLUSTERS OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS CENTRAL/NORTHEAST INDIANA. ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP OTHER SOUTHERN LAKE MICHIGAN IN CLOSER PROXIMITY TO MORE PRONOUNCED UPPER LEVEL DIFFLUENCE DOWNSTREAM OF VIGOROUS NORTHERN PLAINS UPPER TROUGH. AREAS ROUGHLY ALONG AND SOUTHEAST OF A HUNTINGTON INDIANA TO FORT WAYNE INDIANA TO DEFIANCE LINE HAVE LIKELY RECEIVED BETWEEN A HALF INCH TO AN INCH OF RAINFALL SO FAR THIS MORNING. SOME OF THESE SAME LOCATIONS ACROSS NORTHWEST OHIO HAVE ALSO RECEIVED HEAVY RAINFALL YESTERDAY. GIVEN INCREASING CONFIDENCE IN SIGNIFICANT RAINFALL LATE TONIGHT INTO SUNDAY EVENING ALONG WITH RECENT HEAVY RAIN...WILL BE ISSUING A FLASH FLOOD WATCH SHORTLY FOR FAR NORTHEAST INDIANA...PORTIONS OF SOUTH CENTRAL LOWER MICHIGAN....AND ALL OF NORTHWEST OHIO COUNTIES FROM 06Z TONIGHT TO 06Z MONDAY. IN TERMS OF CONVECTIVE POTENTIAL...15Z RUC ANALYSIS DEPICTS 1000-1500 J/KG OF 100 HPA MLCAPES ACROSS MUCH OF WESTERN HALF OF THE AREA WITH 0 TO 6 KM BULK SHEAR VALUES IN THE 25 TO 30 KNOT RANGE. DESPITE SIGNIFICANT CLOUD COVER...DEEP MOISTURE PROFILES SHOULD CONTINUE TO YIELD CAPES ON THE ORDER OF 1000-1500 J/KG THIS AFTERNOON. DEEP LAYER SHEAR TO ALSO INCREASE LATE AFTERNOON ACROSS WESTERN HALF OF THE AREA AS A 500 HPA SPEED MAX LIFTS INTO NORTHWEST INDIANA AFTER 21Z. THUS...NO CHANGE IN THINKING FROM PREVIOUS FORECAST WITH LOW/ISOLATED SEVERE THREAT ACROSS ESPECIALLY WESTERN AREAS LATE AFTERNOON/EARLY EVENING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 342 AM EDT SAT OCT 5 2013 GRADUAL APPROACH OF IMPRESSIVE CLOSED OFF CYCLONIC GYRE EXTENDING THROUGH THE BULK OF THE TROPOSPHERE WILL BRING INCREASING CHANCES FOR RAIN THROUGH THE SHORT TERM PERIOD. SURFACE FRONTAL BOUNDARY EXTENDING INTO THE SOUTHERN GREAT LAKES WILL MOVE LITTLE THROUGH THE PERIOD WITH PERSISTENT THETA-E ADVECTION IN A LARGELY UNCAPPED ENVIRONMENT LEADING TO CONTINUED PERIODS OF CONVECTION. SMALL SCALE VORTICES IN SOUTHWEST FLOW ALOFT EMANATING FROM THE CENTRAL CONUS WILL ALSO SUPPORT INCREASING CHANCES FOR RAINFALL AS THE MAIN SYSTEM APPROACHES. OCCLUSION PROCESS IS ALREADY BEGINNING AND EARLIER NOTED SLOWING TREND HAS CONTINUED. MAIN SURFACE COLD FRONT IS NOT EXPECTED TO REACH OUR CWA UNTIL LATE TONIGHT. WILL STILL BE PLENTY OF RAIN AHEAD OF THE MAIN FRONT THOUGH. TIGHTENING LOW LEVEL MASS GRADIENT ASSOCIATED WITH APPROACHING PV ANOMALY WILL LEAD TO A STRENGTHENING OF THE LLJ AND A CORRESPONDING UPTICK IN 305K ISENTROPIC ASCENT. MOISTURE WILL CERTAINLY NOT BE LACKING EITHER. 305K MIXING RATIOS ARE ABOVE 8 G/KG AND PW VALUES ARE HOVERING AROUND 1.75 INCHES...NEAR THE 99TH PERCENTILE FOR THIS TIME OF YEAR BASED ON REGIONAL UPPER AIR CLIMATOLOGY. EXACT TIMING/PLACEMENT OF CONVECTION REMAINS HIGHLY UNCERTAIN BUT EXPECT COVERAGE TO INCREASE AS THE DAY WEARS ON GIVEN INCREASING DIURNAL INSTABILITY AND APPROACHING TROUGH. LATEST HI-RES GUIDANCE SHOWS CONVECTION NEAR INDIANAPOLIS WILL CONTINUE TO SPREAD NORTH THROUGH THE MORNING WITH A BRIEF BREAK BEFORE ADDITIONAL CONVECTION ARRIVES IN THE LATE AFTERNOON. TRIED TO INCORPORATE THIS INTO THE LATEST POP FORECAST BUT MAINTAINED FAIRLY BROADBRUSH APPROACH GIVEN UNCERTAINTY IN CONVECTIVE TRENDS. HIGHER CONFIDENCE THAT SHOWERS AND THUNDERSTORMS WILL BECOME WIDESPREAD BY TONIGHT THOUGH AS THE COLD FRONT APPROACHES...AND HAVE PUSHED POPS INTO CATEGORICAL VALUES. HIGHS TODAY WILL BE SIMILAR TO YESTERDAY...AS ANY BREAKS IN THE CLOUD COVER WILL ALLOW TEMPS TO MAKE A RUN AT THE MID 80S GIVEN WARM PROFILES ALOFT. LOWS TONIGHT WILL BE HIGHLY DEPENDENT ON EXACT TIMING OF FRONT BUT HAVE RAISED THEM A BIT IN ANTICIPATION OF A SLOWER FRONTAL PASSAGE. LAPSE RATES NEARLY MOIST ADIABATIC WILL LIKELY ONLY SUPPORT AROUND 1000 J/KG OR LESS OF SBCAPE TODAY. DEEP LAYER SHEAR IS ALSO MARGINAL DURING THE DAY AND EXPECT ONLY A SLIGHT CHANCE FOR SEVERE WEATHER...MAINLY IN AREAS THAT SEE A SUSTAINED PERIOD OF INSOLATION THAT ALLOWS INSTABILITY TO BUILD. SHEAR WILL INCREASE BY TONIGHT...BUT INSTABILITY WILL BE AT A MINIMUM AND AGAIN ONLY EXPECTING A LOW RISK OF SEVERE WEATHER AT THE MOMENT. HEAVY RAIN WILL LIKELY BE THE BIGGEST THREAT. A VERY MOIST ENVIRONMENT AND CONTINUED POTENTIAL FOR TRAINING STORMS COULD LEAD TO HIGH RAINFALL TOTALS BY THE TIME ALL IS SAID AND DONE EARLY NEXT WEEK. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 342 AM EDT SAT OCT 5 2013 RATHER DRAMATIC CHGS REQUIRED TO BEGIN THE PD ON ACCOUNT OF CONTD MODEL CONSENSUS SLWG IN EWD PROGRESSION OF PLAINS BOWLING BALL. INTERESTINGLY STILL SOME SIG SPREAD ALOFT STILL AT THIS TIME RANGE W/POSITION AND INTENSITY OF MID LVL CYCLONE WHICH RANGES FROM NRN IL IN NAM TO SRN IL IN GEM AT FHR60. REGARDLESS ENOUGH OF A CONSENSUS SIGNAL EXISTS TO EXTEND/BUMP POPS/WX THROUGH MON NIGHT. HWVR WILL FORGO ALLBLEND POP GUIDANCE FOR TUE IN LIGHT OF RAPID UPSTREAM HGT RISES FOLLOWING IN WAKE OF UPR TROUGH WHICH AT THAT POINT SHLD BE IN SE CANADA. OF GREATEST INTEREST W/SLWG SOLUTIONS ALOFT IS CONTD PUMP OF ANOMALOUS GOMEX MSTR FLUX INTO THE GREAT LAKES INADV OF MIDLVL CYCLONE WHICH SHOWS LTL SIGN OF WKNG UNTIL MON. SLWR EWD ADV OF FNTL BNDRY ALG W/PWS OF NEAR 1.8IN (99TH PERCENTILE) WOULD PREPOSE AT LEAST THE ERN HALF OF CWA FOR A CLASSIC MADDOX TYPE I HEAVY RAIN EVENT AND NOTED IN SVRL DETERMINISTIC QPF SOLUTIONS SUN-SUN NIGHT. SINCE THIS THREAT IS XPCD TO DVLP DY2 WILL FOLLOWUP PRIOR WELL DESERVED ESF. AS AN ASIDE...FAIR NUMBER OF SOLUTIONS DEPICT THE DVLPMNT OF A SFC FNTL WAVE SUN AFTN WHICH IF TRUE WOULD YIELD A HEIGHTENED RISK FOR LOW TOPPED SUPERCELLS ACRS ERN IN/WRN OH AND INHERENT TOR THREAT W/FVRBL OVERLAP OF MIXED LYR CAPE/SHEAR. OTRWS SWD TRENDING PROGRESSION OF AT LEAST MOD INTENSE MID LVL CYCLONE LEADS TO ADDNL ESCALATION/EXPANSION OF POPS MON AFTN/MON NIGHT. IN FACT SWD CNTRD CLUSTER OF SVRL SOLUTIONS INCLUDING GFS/GEM WOULD PORTEND A SECONDARY DEFORMATION ZONE DVLPG IN RESPONSE TO TRAILING FNTL WAVE MON NIGHT W/ASSUMED SEPARATION W/REMNANTS OF TS KAREN AS SOME SEMBLANCE OF THE TROWAL REMAINS INTACT. GIVEN ALL OF THE ABOVE...SIG CHGS TO TEMPS WERE MADE SUN/MON. HWVR SIG MODERATION STILL ON TAP IN WAKE OF THIS INTENSE SYS MID WEEK TIMED W/SECONDARY DEEP WRN TROUGH DVLPMNT AND DOWNSTREAM RIDGE AMPLIFICATION W/RTN TO ABV NORMAL TEMPS XPCD BY THU. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 555 AM EDT SAT OCT 5 2013 AREA OF CONVECTION CURRENTLY OVER CENTRAL INDIANA WILL CONTINUE TO SLOWLY WORK NORTHWARD THIS MORNING...AIDED BY PERSISTENT THETA-E ADVECTION AND A WEAK SHORTWAVE EMBEDDED IN SOUTHWEST FLOW ALOFT. PRECIP MAY CLIP KFWA BUT PLAN TO LEAVE OUT THUNDER MENTION SINCE LIGHTNING HAS BEEN FAIRLY ISOLATED AND MAY PASS TO THE SOUTHEAST OF THE TERMINAL. SPORADIC SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE FOR MUCH OF THE TAF PERIOD AND TIMING THIS PRECIP WILL BE NEARLY IMPOSSIBLE MORE THAN A FEW HOURS OUT. HAVE HIGHLIGHTED LATE AFTERNOON AS THE BEST CHANCE GIVEN DIURNAL INSTABILITY PEAK BUT SCATTERED CONVECTION WILL BE POSSIBLE THROUGH THE OVERNIGHT PERIOD WITH MVFR...OR LOWER...CONDITIONS IN THE STRONGER STORMS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR INZ007-009-018-026-027-033-034. MI...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR MIZ081. OH...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR OHZ001-002-004-005-015-016-024-025. LM...NONE. && $$ UPDATE...MARSILI SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...T AVIATION...AGD 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 TWIN CITIES/CHANHASSEN MN
1048 AM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 1034 AM CDT SAT OCT 5 2013 A TRICKY FORECAST TO SAY THE LEAST FOR TODAY. DRY SLOT HAS MOVED IN BEHIND THE OCCLUDED FRONT THIS MORNING...WITH PARTIAL CLEARING OF SKIES SEEN WEST AND SOUTH OF THE TWIN CITIES. AFTER MAKING GOOD PROGRESS OVERNIGHT...THIS CLEARING HAS PUT ON THE BREAKS AS THE LOW OVER SE SODAK HAS STARTED TO DRIFT ESE. THIS WILL KEEP THE CLEARING FROM MAKING IT MUCH FARTHER NORTH...BUT IT WILL CONTINUE TO SLOWLY CRAWL TOWARD THE EAST TODAY. OF COURSE AS THIS IS GOING ON THE BIGGEST CHANGE TO THE FORECAST IS THE ADDITION OF SHOWERS THIS AFTERNOON FROM MANKATO TO ST. CLOUD ON EAST. THE HRRR HAS BEEN SHOWING THIS AREA OF SHOWERS DEVELOPING BACK TO THE WEST FOR SEVERAL RUNS NOW. LOOKING AT THE RAP...THIS IS IN RESPONSE TO A STRONG BAND OF FGEN COMING UP FROM IOWA IN THE H7-H5 LAYER. LOOKING DOWN TO THE SOUTHWEST ON SATELLITE...YOU CAN SEE THIS AREA OF PRECIP STARTING TO TAKE SHAPE FROM ERN KANSAS UP INTO WRN IOWA. BOOSTED POPS UP TO AROUND 50 PERCENT BACK TO THE CITIES THIS AFTERNOON...BUT IF THE HRRR IS CORRECT...MAY NEED TO BOOST THEM UP SIGNIFICANTLY IN THE NEAR FUTURE...ESPECIALLY CONSIDERING ALL 4 MEMBERS OF THE 05.09 HOPWRF SHOW SOMETHING SIMILAR HAPPENING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 342 AM CDT SAT OCT 5 2013 THE POTENCY OF THIS EARLY FALL SYSTEM WAS AGAIN ON DISPLAY LAST NIGHT WITH STRONG TO SEVERE STORMS IN THE WARM SECTOR AND A RAGING BLIZZARD IN WESTERN SOUTH DAKOTA. FURTHERMORE...THE SYSTEM HAS BEEN OCCLUDED FOR 12-18 HOURS NOW AND WE STILL SAW A 1-2 MB MSLP PRESSURE DROP OVERNIGHT. THE TROWAL IS CREATING A HOME RUN HITTING DEFORMATION BAND FROM NORTHERN MN TO ND TO SD. IN FACT...THE PRECIP SHIELD ALONG THE COLD CONVEYOR BELT ACTUALLY EXTENDS ALL THE WAY FROM WYOMING TO MICHIGAN...AND THUNDERSTORMS ALONG THE COLD FRONT EXTEND FROM MICHIGAN TO TEXAS. NOT A SMALL SYSTEM BY ANY MEANS. THE FORECAST AREA WILL FIND ITSELF IN THE DRY SLOT MOST OF THE DAY TODAY AND ALSO TONIGHT TO SOME DEGREE. HOWEVER SOME DRIZZLE IS POSSIBLE AND THE CLOUDS SHOULD LARGELY STAY IN TACT. THE OCCLUDED BOUNDARY ISN`T GOING ANYWHERE...ESPECIALLY FOR CENTRAL MN/WI. SOUTHERN PORTIONS OF THE FORECAST AREA /THAT`S RIGHT...SOUTHERN/ ARE CLOSER TO THE COLDER AND DRIER AIR...SO THERE IS A BETTER CHANCE OF AT LEAST PARTIAL CLEARING TODAY IN SOUTHERN MN. MUCH COLDER AIR ALOFT ARRIVES TONIGHT...SO THE STRATUS WON`T BE FAR BEHIND EVEN IF THERE IS CLEARING DURING THE DAY TODAY. THE 00-06Z GUIDANCE IS TOO FAR SOUTH WITH THE DEFORMATION PRECIP BAND THIS MORNING...AS THE FORECAST AREA IS VIRTUALLY PRECIP FREE. IT`S ALSO NOT DEEP ENOUGH WITH THE SURFACE LOW. TRIED TO KEEP THE POPS TODAY ON THE OUTER EDGES OF THE FORECAST AREA TO COUNTER THIS AND ALSO TO STAY CLOSE TO SURROUND FORECAST OFFICES. OTHERWISE...WINDS WILL FALL OFF AS THE LOW SLOWLY FILLS AND MOVES OVERHEAD. IF THE CLOUDS CLEAR ANYWHERE TONIGHT...FOG COULD BE A PROBLEM...TOOK THE SIDE OF LOW STRATUS FOR NOW. NEAR STEADY TEMPERATURE TODAY SO MADE LITTLE ADJUSTMENT TO THE PREVIOUS FORECAST. WE ADJUSTED DEWPOINTS BY KEEPING SLIGHTLY HIGHER VALUES NEAR THE FRONT AND COOLER VALUES CLOSER TO THE DRY SLOT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 342 AM CDT SAT OCT 5 2013 THE SFC LOW FROM THE POTENT/DEEP SYSTEM AFFECTING THE REGION WILL SHIFT INTO WI BY DAYBREAK SUN MRNG WHILE THE LOW PRES CENTER ALOFT WILL SHIFT SE INTO NRN IA. AS THESE TWO LOWS MOVE EAST IN TANDEM SLOWLY DURG THE DAY ON SUN...THE DRY SLOT OVER MUCH OF THE AREA WILL FILL BACK IN WITH DEEPER MOISTURE WRAPPING AROUND THE UPPER LEVEL LOW. COLD ALOFT COMBINED WITH LOW LEVEL WINDS SHIFTING TO A MORE NLY DIRECTION WILL AID IN KEEPING LOW CLOUDS IN PLACE FOR MUCH OF THE DAY...ALONG WITH A DRIZZLE/RAIN SCENARIO FOR SENSIBLE WX. THE UPPER LOW WILL SHIFT ESE INTO CENTRAL IL BY MON MRNG...DRAGGING MUCH OF THE MOISTURE WITH IT BUT THERE WILL STILL BE A CHC FOR LINGERING SHOWERS IN WRN WI ON MON WHILE SRN/CENTRAL MN STARTS TO CLEAR OUT. CONDS WILL GRADUALLY IMPROVE DURG THE DAY ON MON AS HIGH PRES FROM SW CANADA DROPS IN. DESPITE THE COOL ORIGIN OF THIS AIRMASS...IT WILL BE QUICKLY MODIFIED BY AN UPPER LEVEL RIDGE THAT WITH INCRG H5 HEIGHTS WILL SPELL A WARMING TREND ALONG WITH A PROLONGED DRYING-OUT PERIOD FOR THE AREA. DRY WX IS FORECAST MON THRU THU WITH HIGHS RISING BACK INTO THE MID 70S. MODELS CONTINUE TO ADVERTISE ANOTHER POTENT SYNOPTIC-SCALE LOW PRES SYSTEM TO DEVELOP IN THE LEE OF THE ROCKIES THU NIGHT INTO FRI MORNING...WITH IT QUICKLY MOVG NEWD INTO THE DAKOTAS FRI. THIS MAY ALLOW FOR SOME MID-TO-LATE DAY SHWRS/TSTMS OVER WRN MN ON FRI AS THIS SYSTEM ADVANCES. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 623 AM CDT SAT OCT 5 2013 CONDITIONS HAVE GENERALLY BEEN IFR WITH LIFR AT TIMES AND MVFR AT OTHERS. WE EXPECTED LITTLE CHANGE FOR THE NEXT 2-4 AT THE TAF SITES AS THE DRIER AIR TAKES ITS TIME TO ARRIVE. HOWEVER...WE DO EXPECT IMPROVEMENT BY THE LATE MORING OR EARLY AFTERNOON. ITS HARD TO IMAGINE SKIES GOING MOSTLY SUNNY FOR TOO LONG...AS CU WITH MVFR CEILINGS SHOULD FILL IN...BUT WE THINK KMSP/KEAU/KRNH/KSTC ALL HAVE A CHANCE FOR MVFR OR EVEN VFR THIS AFTERNOON. LITTLE RAIN IS EXPECTED TODAY AND EVEN TONIGHT - LIGHT RAIN THIS MORNING OR DRIZZLE AS LONG AS THERE ARE LOW CLOUDS AROUND. KMSP... LOW CEILINGS WILL CONTINUE FOR WHAT REMAINS OF THE EARLY MORNING...BUT WE HAVE HIGH CONFIDENCE IN IMPROVEMENT BY THE EARLY AFTERNOON. ANY CLEARING LATER TODAY SHOULD BE RELATIVELY SHORT LIVED WITH WRAP AROUND CLOUD COVER MOVING BACK IN LATE THIS EVENING. ONLY A LITTLE BIT OF LIGHT RAIN OR DRIZZLE TODAY AND THAT SHOULD PRIMARILY BE CONFINED TO THE MORNING. THE STEADIER LIGHT RAIN RETURNS TOMORROW. /OUTLOOK FOR KMSP/ SUN...MVFR OR IFR LIKELY. PERIODS OF -RA/-DZ. WINDS NW 10-15 KTS. MON...VFR...MVFR POSSIBLE EARLY. WINDS W 5-10 KT. TUE...VFR. WINDS S 5-10 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ UPDATE...MPG SHORT TERM...CLF LONG TERM...JPC AVIATION...CLF
AREA FORECAST DISCUSSION
NWS DULUTH MN
1030 AM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 1029 AM CDT SAT OCT 5 2013 THE SURFACE LOW WAS LOCATED IN SOUTHEAST SOUTH DAKOTA AS OF 15Z WITH AN OCCLUDED FRONT EXTENDING FROM THIS LOW ACROSS PORTIONS OF S-C MINNESOTA INTO FAR SOUTHWEST WISCONSIN. 925MB BOUNDARY IS IN NEARLY THE SAME LOCATION WITH HIGHER THETA-E AIR NORTH AND EAST OF THE BOUNDARY. THIS FRONT MARKED A CLEARING LINE WITH DRY CONDITIONS BEHIND IT OVER MUCH OF SOUTHERN MINNESOTA. LIGHT RAIN/DRIZZLE CONTINUED OVER PORTIONS OF THE NORTHLAND THIS MORNING...BUT WASN`T REAL WIDESPREAD. WE TRIMMED BACK SOME ON POPS THROUGH MID AFTERNOON BUT MAY HAVE TO FURTHER AS SEVERAL OBSERVATIONS WERE NOT REPORTING ANY RAIN AS OF 15Z. WE DO EXPECT AN INCREASE IN COVERAGE LATER THIS AFTERNOON AS THE STACKED LOW PRESSURE SYSTEM MOVES FURTHER EAST. THE LATEST HRRR WAS DOING A DECENT JOB DEPICTING THE LIGHT RAIN THIS MORNING AND SHOWS COVERAGE INCREASING QUITE A BIT MID TO LATE AFTERNOON ACROSS THE SOUTHERN THIRD...THEN FURTHER NORTH THIS EVENING. THE 12Z NAM SUPPORTS THE HRRR BUT STILL MAY BE OVERDONE WITH IT`S QPF. AREAS OF DRIZZLE WILL ALSO OCCUR AROUND LAKE SUPERIOR. WE CONTINUE TO MONITOR RADAR TRENDS AND LATEST MODEL OUTPUT AND ADJUST AS NEEDED. IT REMAINS WINDY AROUND LAKE SUPERIOR...ESPECIALLY FROM SILVER BAY TO THE TWIN PORTS AND ALONG THE BAYFIELD PENINSULA. KDLH WAS GUSTING TO 42 MPH AS OF THE 1008 AM OBSERVATION AND TO 46 MPH ON PARK POINT. WE`LL KEEP THE WIND ADVISORY GOING AS IS FOR NOW. WE MAY NEED TO EXTEND IT FOR THE TWIN PORTS AREA TO TWO HARBORS/SILVER BAY. THE WIND WASN`T AS STRONG ACROSS BAYFIELD/ASHLAND COUNTIES BUT SOME HIGHER GUSTS WILL REMAIN POSSIBLE THERE AS WELL. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 410 AM CDT SAT OCT 5 2013 AT 4 AM...RAIN CONTINUED TO MOVE NORTHWARD ACROSS THE CWA. THE MASSIVE LOW PRESSURE SYSTEM WAS LOCATED IN CENTRAL SOUTH DAKOTA...WITH AN OCCLUDED FRONT STRETCHING EASTWARD THROUGH SW MN. TEMPERATURES AT 4 AM WERE GENERALLY IN THE MID TO UPPER 40S NORTH AND LOWER TO MIDDLE 50S SOUTH. STRONG WINDS CONTINUED NEAR LAKE SUPERIOR...WITH KDYT AND KDLH STILL GUSTING ABOVE 40 MPH. THE RAIN HAD DIMINISHED CONSIDERABLY ACROSS THE SOUTHERN THIRD OF THE CWA BUT CONTINUED FROM THE TWIN PORTS NORTHWARD. THE MAIN FOCUS FOR TODAY THROUGH SUNDAY IS THE EXTENT AND TIMING OF VARIOUS WAVES OF PRECIPITATION. THE NAM AND THE NSSL AND NCEP WRF RUNS SEEM TO HAVE A DECENT HANDLE ON THE SITUATION. THEY ALL BRING A REPRIEVE IN THE RAIN TO THE SOUTHERN CWA...BEFORE INCREASING AGAIN THIS AFTERNOON. DESPITE SOME BREAKS IN THE PRECIPITATION...THERE SHOULD BE AREAS OF DRIZZLE AS WELL. WILL CONTINUE WITH HIGH POPS. A LITTLE CONCERNED WE MAY NEED TO EVENTUALLY PULL BACK ON POPS IN THE SOUTH...BUT KEPT THEM HIGH DUE TO THE POTENTIAL FOR DRIZZLE. RAIN SHOULD BECOME WIDESPREAD AGAIN TONIGHT...AS SURFACE LOW PRESSURE RE-FORMS OVER WISCONSIN. FOR THAT REASON...WILL CONTINUE WITH HIGH POPS TONIGHT...AND THEN GRADUALLY DECREASE IN PLACE AS THE LOW STARTS TO FALL APART ON SUNDAY. WILL CONTINUE POPS THROUGHOUT THE DAY THOUGH...AS THERE SHOULD BE SOME LINGERING PRECIPITATION. WILL CONTINUE WITH THE WIND ADVISORY FOR TODAY DUE TO THE STRONG EASTERLY WINDS COMING OFF LAKE SUPERIOR. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 410 AM CDT SAT OCT 5 2013 ANOMALOUS SFC/MID LVL LOW WILL DRIFT EAST OF REGION BE EARLY MONDAY AS SPLIT FLOW IN WESTERLIES ALLOWS NRN BRANCH TO DEEPEN OVER REGION. PRECIP WILL GRADUALLY DIMINISH OVER THE ERN CWA AS CYCLONIC CIRCULATION LOOSENS ITS GRIP MONDAY. MDLS AGREE THAT A RELATIVELY QUIET DRY WEATHER PATTERN WILL COMMENCE TUESDAY AND PERSIST THROUGH THE WEEK. SYNOPTIC PATTERN WILL FEATURE A DEVELOPING LARGE AMPLITUDE UPPER TROF OVER CALIFORNIA WITH A BROAD UPPER RIDGE ACROSS THE NRN PLAINS AND THE WRN GT LAKES. A SFC TROUGH WILL BEGIN TO FORM OVER THE PLAINS AND EXTEND NORTH INTO NWRN MN BY WED EVENING. ALTHOUGH A WARM ADVECTION REGIME WILL BECOME MORE PRONOUNCED ACROSS THE CWA AT THIS TIME IT APPEARS THE MORE FAVORABLE LIFT WILL OCCUR TO THE WEST OF THE REGION THROUGH THURSDAY. CONFIDENCE LOWERS BY FRIDAY AS TO HOW FAR EAST THE EJECTING MID LVL SYSTEM WILL TRACK DUE TO DOWNSTREAM UPPER RIDGE OVER MS RIVER VALLEY. WILL KEEP MAINLY DRY OVER ALL OF CWA THROUGH FRIDAY BEFORE ALLOWING POPS TO RENTER THE CWA FRIDAY NIGHT. TEMPS WILL RISE ABOVE CLIMO MOST OF THE WEEK. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 643 AM CDT SAT OCT 5 2013 INITIAL AREA OF RAIN IS PUSHING NORTH OF MOST TERMINALS WITH REDEVELOPMENT OVER SERN MN. LOW CLOUDS WILL BE EXTENSIVE TODAY AS MID LVL DRY SLOT MOVES OVERHEAD. CONFIDENCE ON REDEVELOPMENT OF RAIN AT MOST TERMINALS IS LOW. SHOULD SEE SOME INCREASE IN CEILINGS TODAY WITH BDRY LYR WARMING BUT LOWERING OVERNIGHT. && .PRELIMINARY POINT TEMPS/POPS... DLH 49 44 51 41 / 80 80 60 20 INL 47 39 54 38 / 70 50 40 10 BRD 52 44 53 40 / 80 80 60 20 HYR 57 46 59 41 / 80 80 50 30 ASX 53 46 57 44 / 80 80 60 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR MNZ020-037. WI...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR WIZ001-002. LS...GALE WARNING UNTIL 10 PM CDT THIS EVENING FOR LSZ141>147. SMALL CRAFT ADVISORY UNTIL 4 AM CDT SUNDAY FOR LSZ121-140-148. && $$ UPDATE...MELDE SHORT TERM...DAP LONG TERM...CANNON AVIATION...CANNON
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
637 AM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 THE MSAS SHOWS THE SFC LOW NEARLY STATIONARY THIS MORNING ACROSS SCNTL SD. THE LOW IS IN THE PROCESS OF DOING A LOOP. THIS AFTERNOON IT WILL DRIFT EAST AT 5 MPH INTO SERN SD AND THIS IS CONSISTENT WITH THE MOTION OF THE 500 MB LOW AT JUST 6 KT. VERY SLOW STORM MOTIONS OF THIS TYPE...5 MPH...OFTEN PRODUCE HIGH WIND EVENTS IN THE CNTL PLAINS. THE GFS...ECM AND RAP SHOW SUSTAINED WINDS INCREASING TO AROUND 40 MPH ACROSS NCNTL NEB THIS AFTERNOON WITH GUSTS TO 58 MPH IN THE RAP AND HRRR MODELS. THE NAM KEEPS THE GUSTS BELOW 58 MPH THIS AFTN. MEANWHILE THE MET GUIDANCE SHOWS NO HIGH WIND EVENT AT ALL WHILE THE MAV GUIDANCE FAVORS SWRN NEB. THE MULTI LAYER WINDS IN THE RAP MODEL FROM H850MB TO H700MB KEEP WINDS AT 60 KTS OR LESS AND THIS IS CONSISTENT WITH A HIGH END WIND ADVISORY WITH A FEW GUSTS TO 58 MPH. THUS THERE IS A SPLIT IN THE MODEL DATA. A HIGH END WIND ADVISORY EVENT WOULD APPEAR TO BE THE MOST LIKELY SOLN INDICATED BY THE MODELS BUT LOCAL STUDIES SUGGEST A HIGH WIND EVENT WOULD UNFOLD THIS AFTERNOON. A WIND ADVISORY WILL CONTINUE TODAY ACROSS ALL AREAS EXCEPT WHERE THE WINTER STORM WARNING IS IN EFFECT. WINTER STORM CONDITIONS ARE LIKELY ONGOING ACROSS NRN SHERIDAN AND WRN CHERRY COUNTIES THIS MORNING. THE RADAR MAY BE OVERSHOOTING THE DENDRITIC LAYER. THE ELLSWORTH NEDOR CAM IS QUIET WHILE THE RUSHVILLE CAM CONTINUES TO SHOW SNOW AND BLOWING SNOW WITH VISIBILITY AROUND 2 MILES OR SO. THE 08Z KIEN OB SHOWS 1/2 MILE VISIBILITY WITH A VERTICAL VISIBILITY OF JUST 500 FEET. THE REST OF THE NEDOR CAMS ARE DARK SO WE WILL HAVE TO WAIT FOR SUNRISE TO GET A BETTER ANALYSIS OF THE SITUATION ACROSS NW NEB. THE WINTER STORM WARNING WILL CONTINUE UNTIL 18Z AS FORECAST. GIVEN THE UPPER LOW HAS STALLED ACROSS THE CNTL PLAINS...THE MODEL CONSENSUS SHOWS WRAPAROUND RAIN AND SNOW TODAY THROUGH SUNDAY MORNING. THE UPPER LEVEL LOW IS EXPECTED TO CONTINUE MOVING SLOWLY EAST SOUTHEAST INTO SRN IOWA BY LATE SUNDAY AFTERNOON. A MULTI MODEL CONSENSUS WAS USED FOR POPS TONIGHT AND SUNDAY. THE RAP MODEL WAS USED EXCLUSIVELY FOR THE TODAY PERIOD. NONE OF THE MODELS ARE SHOWING VERY HEAVY QPF AND SNOW TOTALS OF 2 INCHES OR LESS ARE EXPECTED BASED ON THAT OUTPUT. THERE IS SOME UNCERTAINTY WITH THIS FORECAST AS THE 850 MB MOISTURE TRANSPORT IS STILL QUITE STRONG ACROSS THE NRN PLAINS AND OCCASIONAL LIGHTNING STRIKES ARE STILL SHOWING UP AT 08Z. THE NAM WHICH APPEARS TO HAVE THE BEST HANDLE THE MASSIVE QPF ASSOCIATED WITH THIS STORM GENERALLY KEEPS QPF LESS THAN 0.10 INCHES IN ANY 3 HOUR PERIOD ACROSS NRN NEB. OTHERWISE...HIGHS TODAY RISE INTO THE 30S AND 40S ACCORDING TO A BLEND OF BIAS CORRECTED AND DETERMINISTIC DATA. THE MODELS ARE FORECASTING LOWS IN THE MID 20S TONIGHT ACROSS THE SNOW FIELD ACROSS NWRN NEB WITH LOWER 30S ELSEWHERE. IF THE WRN HALF OF THE FORECAST AREA CLEARS OUT TONIGHT AS INDICATED IN THE MODELS THEN THESE LOWS COULD BE 5 OR MORE DEGREES COLDER. HIGHS SUNDAY RISE INTO THE 40S ACROSS THE SNOW COVERED NORTHWEST WITH 50S AND 60S ELSEWHERE. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 BY SUNDAY NIGHT THE LOW PRESSURE SYSTEM WILL HAVE PUSHED TOWARDS THE MID MISS RVR VALLEY AND THE WRAP AROUND MOISTURE WILL HAVE SHIFTED INTO EASTERN NEB. MEANWHILE AN UPPER LEVEL RIDGE WILL BUILD ACROSS THE WEST...AS THE NEXT TROUGH PUSHES ACROSS NORTHEASTERN PACIFIC OCEAN. MONDAY THROUGH THURSDAY THE PACIFIC TROUGH WILL DIG TOWARDS THE DESERT SOUTHWEST WHILE THE UPPER RIDGE SHIFTS EAST ACROSS THE PLAINS. AT THE SFC HIGH PRESSURE WILL DOMINATE THE PLAINS THROUGH MUCH OF THE WEEK. THUS EXPECT MILD CONDITIONS WITH 70S AND A FEW MID/UPPER 60S ACROSS THE NW ZONES WHERE SOME INFLUENCE FROM THE HEAVY SNOW PACK IS LIKELY TO LIMIT THE HEATING. ONCE THE SNOW MELTS...COULD SEE MORE WIDESPREAD HIGHS INTO THE 70S ACROSS THE NW. WITH THE WARM AIR MASS...EXPECT SEASONALLY WARM LOWS...GENERALLY IN THE 40S SPOTTED WITH A FEW UPPER 30S. LATE THURSDAY INTO FRIDAY THE LOW OVER THE SW WILL BEGIN TO EJECT ONTO THE NORTHERN PLAINS. MODELS IN FAIR AGREEMENT...CONSIDERING 6/7 DAYS OUT...WITH A TRACK OF THE UPPER LOW ACROSS THE CENTRAL ROCKIES AND INTO S DAKOTA. THE MODELS CONTINUE TO TRACK THE LOW TO THE NE...INTO CANADA OVER THE WEEKEND. AS THE LOW PUSHES ONTO THE ROCKIES...GOOD MOISTURE TRANSPORT WITH S WINDS EXPECTED ACROSS THE AREA. POPS ARE NEEDED FOR THURSDAY INTO FRIDAY...HOWEVER PENDING THE TRACK AND THE DRY SLOT...CONCERNED AMOUNTS MAY NOT AMOUNT TO TOO MUCH OVER PART OF THE CWA. THUS WILL HOLD POPS IN THE SLIGHT CHANCE AND LOWER CHANCE CATEGORY. && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 637 AM CDT SAT OCT 5 2013 STRONG TO PERHAPS HIGH WIND CONDITION TODAY WITH WINDS OPERATING AT 31032G45KT. GIVEN THE STORM MOTION OF JUST 6 KTS INDICATED BY THE RAP MODEL...STRONGER WINDS COULD DEVELOP. IFR/MVFR IN SNOW AND LOW CIGS SHOULD GRADUALLY DRIFT EAST OF HIGHWAY 83 LATE TONIGHT. THIS AREA OF CLOUDS WILL ALSO DRIFT EAST AT 6 KTS. THE AREA AFFECTED WILL BE MOSTLY ALONG AND NORTH OF NEBRASKA HIGHWAY 2. && .LBF WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NEZ008- 022>027-035>038-056>059-069>071. WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR NEZ005. WINTER STORM WARNING UNTIL NOON MDT TODAY FOR NEZ004-094. WIND ADVISORY FROM 10 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR NEZ006-007-009-010-028-029. && $$ LONG TERM...MASEK AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1155 AM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN OVER THE REGION THROUGH TONIGHT THEN LIFT NORTH AS A WARM FRONT ON SUNDAY. THIS WILL KEEP OUR WEATHER UNSETTLED THROUGH THE WEEKEND WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS, PRIMARILY DURING THE DAYLIGHT HOURS. && .NEAR TERM /THROUGH TONIGHT/... 1155 AM UPDATE...CURRENT SFC ANALYSIS SHOWS STATIONARY FRONT SLIGHTLY FURTHER SOUTH THEN YESTERDAY. ATTM IT STRETCHES ACROSS THE SOUTHERN TIER OF NYS THEN DROPS SOUTHEAST INTO THE POCONOS. CONVECTION OVER THE NRN FINGER LAKES REGION HAS ALMOST DISSIPATED AS IT ENCOUNTERED A FAIRLY STABLE AIRMASS WELL NORTH OF THE BOUNDARY. SATELLITE SHOWS STRATUS BEGINNING TO MIX OUT OVER NE PA AND THE SOUTHERN TIER. THESE LOCATIONS WILL SEE SOME SUNNY BREAKS THIS AFTERNOON WITH THE WYOMING VALLEY LIKELY TO SEE THE MOST SUNSHINE. MODELS CONTINUE TO SUGGEST A WEAK SHORT WAVE WILL MOVE ALONG THE BOUNDARY LATER THIS AFTERNOON AND INTO THE EARLY EVENING. CURRENT POPS LOOK REASONABLE WITH ONLY MINOR ADJUSTMENTS. ISOLATED THUNDER IS STILL POSSIBLE LATER TODAY ALONG AND SOUTH OF THE SFC FEATURE. 915 AM UPDATE...LOCAL RADAR SHOWS A CLUSTER OF SHOWERS WITH EMBEDDED ISOLATED THUNDER MOVING INTO THE FINGER LAKES REGION. BASED ON CURRENT MOVEMENT AND HRRR OUTPUT THIS CLUSTER WILL MOVE ACROSS THE FINGER LAKES REGION AND INTO THE NRN CWA THROUGH LATE MORNING. INCREASED POPS IN THE ABOVE MENTIONED AREAS AND INCLUDED ISOLATED T EXCEPT FAR NRN CWA WHERE MODEL SOUNDINGS INDICATE NO INSTABILITY. REST OF FORECAST IN GOOD SHAPE. 620 AM UPDATE... TEMPS HV STAYED UP IN THE 60S UNDER EXTENSIVE STRATUS AND FOG DECK. EXPECT PATCHY DENSE FOG WL CONTINUE THRU 14Z ALONG WITH ISOLD SHOWERS WITH STATIONARY FRONT LURKING ACRS THE AREA. AREA OF SHOWERS MVG INTO NIAGARA FRONTIER AHD OF S/WV MAY MV INTO WRN CNTYS TWD 12Z. KEPT SLGT CHC POPS IN ALL NIGHT FOR CNTRL CNTYS AND EXPECT POPS TO INCRS IN CVRG ACRS TWIN TIERS TWD LATE MRNG. THUS NO CHGS NEEDED AT THIS TIME OTHER THAN T/TD GRIDS TO COME MORE INTO LINE WITH REALITY. PREV DISCUSSION BLO... 330 AM UPDATE... WMFNT IS CURRENTLY STRETCHED FM SFC LOW NR PIERRE SD ALONG THE I-90 CORRIDOR TO BTWN KBUF AND KERI AND ALONG NY/PA BORDER. DO NOT EXPECT MUCH IN THE WAY OF MVMNT TDA AS 1028MB HIPRES RMNS LOCKED ACRS ERN CANADA AND CLOSED LOW JUST CREEPS ALONG, ROUGHLY 100 MILES IN 12 HRS, AS IT WAITS FOR AN UPSTREAM KICKER. AS FOR TDA`S FCST EXPECT ISOLD/SCTD CONVECTION AS WMFNT RMNS OVR AREA. ISOLD SHOWERS EXPECTED UNTIL ABOUT NOON TDA AS ANY EMBEDDED S/WVS MAY KICK SOMETHING OFF WITH FRONTAL BNDRY IN AREA. HWVR AFT ABOUT 16Z INSTABILITY LOOKS TO NOSE INTO REGION MAINLY ALONG BNDRY WITH CAPES BTWN 200-400 J/KG AND K-INDICES APPCHG 35. EXPECT CONVECTION AFT THIS TIME ACRS THE SRN TIER/SUSQ REGION, THEN SOUTH INTO NEPA AFT 18Z. NRN CNTYS EXPECTED TO BE SOCKED IN WITH LOCLDS ALL DAY NORTH OF THE BNDRY SIMILAR TO YDA. THUS HV NOT ADDED ANY THUNDER INTO ZONES ALONG AND NORTH OF THE NY THRUWAY AT THIS TIME. SKIES EXPECTED TO RMN CLDY ACRS NRN AREAS WITH SOME SUN POSSIBLY BREAKING OUT BRIEFLY ACRS THE SOUTH. EXPECT AFTN MAXES SIMILAR TO YDA WITH HIGHS ARND 80 ACRS WRN AND SRN ZONES AND ONLY INTO THE 60S OVR NE CNTYS. FNT WL BEGIN LIFTING NORTH SAT NGT AS HIPRES BUILDS INTO THE CANADIAN MARITIMES AND SRLY WINDS INCRS. EXPECT SLGT/CHC SHOWERS THRU THE OVRNGT ACRS CWA, INCRSG TO LKLY TWD SUN MRNG ACRS NRN ZONES AS EJECTING WV FM UPSTREAM CLOSED LOW RIDES ALONG FRONTAL BNDRY AND INITIATES CONVECTION. OVRNGT LOWS FOR SUN MRNG WL LKLY RMN ARND NRML VALUES (L/M 60S) FOR HIGHS THIS TIME OF YR, NOT EVEN CLOSE TO NORMAL LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 330 AM UPDATE... CWA WL BE IN WM SECTOR ON SUNDAY WITH SCTD CONVECTION EXPECTED OFF AND ON THROUGHOUT THE DAY AS ANY SUBTLE WVS THAT CAN MV THRU WL GENERATE CHCS FOR SHRA/TSRA. FOR NOW, HV NOT MADE MANY CHGS DUE TO UNSETTLED PATTERN AND DIFFICULTY RESOLVING ANY TRIGGERS. AREA RMNS IN WARM SECTOR ON SUN NGT AND CAN EXPECT JUST CHC SHOWERS THRU 12Z MON SO HV DROPPED POPS TO JUST 30% AT THIS TIME FOR THE PD. WARM AND HUMID CONDS WL CONT THRU MON MRNG WITH TEMPS AND TDS IN THE U50S/L60S. MOISTURE FM TROPICAL STORM KAREN PROGGED BY GFS TO WORK UP INTO AREA MON NGT. HWVR, THIS WL ALL DEPEND ON HOW MUCH H5 SYSTEM SLOWS DOWN AND IF FRONTAL BNDRY CAN HOLD OFF ENUF TO BRING MOISTURE INTO AREA. AS OF NOW WITH PW VALUES INCRSG TO BTWN 1.5 AND 1.75 INCHES ON MON NGT EXPECTED 12-HR QPF VALUES FM HPC WL AVG ARND 1 INCH THRU THE END OF THE SHORT TERM. FROPA LOOKS TO HV SLOWED DOWN ENUF TO OCCUR AT THE VRY TAIL END OF THE SHORT TERM. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 345 AM UPDATE... MED RNG GRIDS UPDATED WITH 00Z WPC GDNC (BLENDED WITH SOME GFS/MOS DATA) TO REFLECT A SLOWER MVMNT OF THE UPR LOW...WITH AN EXTENSION OF CHC POPS INTO MID WEEK AND MORE IN THE WAY OF CLDS DUE TO THIS SYSTEM. PREV BLO... 2 PM UPDATE... MAIN INTEREST IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR HEAVY RAIN MONDAY NIGHT. THE MAIN WEATHER PLAYERS WILL BE AN UPPER LEVEL LOW NOW OVER SE WYOMING...AND ASSOCIATED COLD FRONT OVER THE CENTRAL PLAINS. AS THESE FEATURES MOVE EAST THE SOUTHERLY FLOW OF AIR AHEAD OF THEM WILL TRANSPORT MOISTURE...SOME OF IT WILL BE WHATS LEFT OF TS KAREN...NORTHWARD INTO OUR AREA. WITH HIGH VARIANCE IN THE MODELS JUST 24 HOURS AGO...THE 12Z NAM AND GFS ARE FAIRLY SIMILAR IN SHOWING AN AREA OF STEADY RAIN ALONG AND AHEAD OF THE COLD FRONT MOVING INTO OUR AREA MONDAY EVENING. BOTH THE GFS AND WPC GUIDANCE SHOW A GENERAL 1" TO 2" RAIN ACROSS THE AREA MONDAY NIGHT...WITH ISOLATED HIGHER AMOUNTS POSSIBLE. WITH OUR RECENT STRETCH OF DRY WEATHER AND THE PROGRESSIVE NATURE OF THE FRONT (RAIN FALLING IN 12 HOURS OR LESS)...WIDESPREAD PROBLEMS ARE NOT EXPECTED AT THIS EARLY JUNCTURE. IN FACT FOR MOST THIS WILL BE A WELCOME BENEFICIAL FALL RAIN. LATER TUESDAY AND BEYOND...THE GFS IS NOW THE SLOWEST WITH THE UPPER LEVEL LOW MOVING OVER OUR AREA AND KEEPING US CLOUDY/UNSETTLED FOR ONE MORE DAY. WILL LEAN WITH WPC GUIDANCE DRYING US OUT BY TUESDAY NIGHT. HIGH PRESSURE CONTROLS THE REST OF THE PERIOD WITH QUIET WEATHER EXPECTED. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... FNTL BNDRY DRAPED OVER THE TWIN TIERS/NRN PA WITH LIFR/IFR TO THE N OF THE FNT. PROFILES SUGGEST THESE CONDITIONS TO CONTINUE THRU THE MID MRNG HRS...WITH ITH/ELM/BGM/SYR/AVP BLO ALT MINS AND BRIEFLY LIKELY BLO AIRPORT MINS THRU 14Z. COULD SEE SCT -SHRA THIS MRNG 14-16Z AT SYR/RME IF ACTIVITY OVER WRN NY HOLDS TOGETHER. XPCT CIGS TO SLOWLY LIFT LATE THIS MRNG/AFTN TO MVFR MOST SITES. CHCS FOR SHRA APPEAR TO BE GREATEST THIS AFTN NEAR THE FNT AND INCLUDED TEMPOS FOR SHRA AT ITH/ELM/BGM/AVP THIS AFTN. POTNL FOR TSRA ACRS SRN SITES WHICH MAY BE ADDED WITH LATER FCST UPDATES. TNGT...MVFR XPCTD TO PREVAIL THRU 06Z...WITH POTNL FOR MVFR/IFR MAINLY AFTER 06Z AS -SHRA MOV BACK IN. WINDS ON THE LGT SIDE AND RATHER VRBL...MAINLY FROM A NORTHERLY DIRECTION ACRS CNTRL NY...BECMG ERLY OR SELY TNGT. OUTLOOK... SATURDAY NIGHT THROUGH WEDNESDAY...AN UNSETTLED PERIOD...WITH SCATTERED TO WIDESPREAD SHOWERS ANTICIPATED...ALG WITH THE LIKELIHOOD OF RESTRICTIVE CONDS FROM TIME TO TIME. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
922 AM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN OVER THE REGION THROUGH TONIGHT THEN LIFT NORTH AS A WARM FRONT ON SUNDAY. THIS WILL KEEP OUR WEATHER UNSETTLED THROUGH THE WEEKEND WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS, PRIMARILY DURING THE DAYLIGHT HOURS. && .NEAR TERM /THROUGH TONIGHT/... 915 AM UPDATE...LOCAL RADAR SHOWS A CLUSTER OF SHOWERS WITH EMBEDDED ISOLATED THUNDER MOVING INTO THE FINGER LAKES REGION. BASED ON CURRENT MOVEMENT AND HRRR OUTPUT THIS CLUSTER WILL MOVE ACROSS THE FINGER LAKES REGION AND INTO THE NRN CWA THROUGH LATE MORNING. INCREASED POPS IN THE ABOVE MENTIONED AREAS AND INCLUDED ISOLATED T EXCEPT FAR NRN CWA WHERE MODEL SOUNDINGS INDICATE NO INSTABILITY. REST OF FORECAST IN GOOD SHAPE. 620 AM UPDATE... TEMPS HV STAYED UP IN THE 60S UNDER EXTENSIVE STRATUS AND FOG DECK. EXPECT PATCHY DENSE FOG WL CONTINUE THRU 14Z ALONG WITH ISOLD SHOWERS WITH STATIONARY FRONT LURKING ACRS THE AREA. AREA OF SHOWERS MVG INTO NIAGARA FRONTIER AHD OF S/WV MAY MV INTO WRN CNTYS TWD 12Z. KEPT SLGT CHC POPS IN ALL NIGHT FOR CNTRL CNTYS AND EXPECT POPS TO INCRS IN CVRG ACRS TWIN TIERS TWD LATE MRNG. THUS NO CHGS NEEDED AT THIS TIME OTHER THAN T/TD GRIDS TO COME MORE INTO LINE WITH REALITY. PREV DISCUSSION BLO... 330 AM UPDATE... WMFNT IS CURRENTLY STRETCHED FM SFC LOW NR PIERRE SD ALONG THE I-90 CORRIDOR TO BTWN KBUF AND KERI AND ALONG NY/PA BORDER. DO NOT EXPECT MUCH IN THE WAY OF MVMNT TDA AS 1028MB HIPRES RMNS LOCKED ACRS ERN CANADA AND CLOSED LOW JUST CREEPS ALONG, ROUGHLY 100 MILES IN 12 HRS, AS IT WAITS FOR AN UPSTREAM KICKER. AS FOR TDA`S FCST EXPECT ISOLD/SCTD CONVECTION AS WMFNT RMNS OVR AREA. ISOLD SHOWERS EXPECTED UNTIL ABOUT NOON TDA AS ANY EMBEDDED S/WVS MAY KICK SOMETHING OFF WITH FRONTAL BNDRY IN AREA. HWVR AFT ABOUT 16Z INSTABILITY LOOKS TO NOSE INTO REGION MAINLY ALONG BNDRY WITH CAPES BTWN 200-400 J/KG AND K-INDICES APPCHG 35. EXPECT CONVECTION AFT THIS TIME ACRS THE SRN TIER/SUSQ REGION, THEN SOUTH INTO NEPA AFT 18Z. NRN CNTYS EXPECTED TO BE SOCKED IN WITH LOCLDS ALL DAY NORTH OF THE BNDRY SIMILAR TO YDA. THUS HV NOT ADDED ANY THUNDER INTO ZONES ALONG AND NORTH OF THE NY THRUWAY AT THIS TIME. SKIES EXPECTED TO RMN CLDY ACRS NRN AREAS WITH SOME SUN POSSIBLY BREAKING OUT BRIEFLY ACRS THE SOUTH. EXPECT AFTN MAXES SIMILAR TO YDA WITH HIGHS ARND 80 ACRS WRN AND SRN ZONES AND ONLY INTO THE 60S OVR NE CNTYS. FNT WL BEGIN LIFTING NORTH SAT NGT AS HIPRES BUILDS INTO THE CANADIAN MARITIMES AND SRLY WINDS INCRS. EXPECT SLGT/CHC SHOWERS THRU THE OVRNGT ACRS CWA, INCRSG TO LKLY TWD SUN MRNG ACRS NRN ZONES AS EJECTING WV FM UPSTREAM CLOSED LOW RIDES ALONG FRONTAL BNDRY AND INITIATES CONVECTION. OVRNGT LOWS FOR SUN MRNG WL LKLY RMN ARND NRML VALUES (L/M 60S) FOR HIGHS THIS TIME OF YR, NOT EVEN CLOSE TO NORMAL LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 330 AM UPDATE... CWA WL BE IN WM SECTOR ON SUNDAY WITH SCTD CONVECTION EXPECTED OFF AND ON THROUGHOUT THE DAY AS ANY SUBTLE WVS THAT CAN MV THRU WL GENERATE CHCS FOR SHRA/TSRA. FOR NOW, HV NOT MADE MANY CHGS DUE TO UNSETTLED PATTERN AND DIFFICULTY RESOLVING ANY TRIGGERS. AREA RMNS IN WARM SECTOR ON SUN NGT AND CAN EXPECT JUST CHC SHOWERS THRU 12Z MON SO HV DROPPED POPS TO JUST 30% AT THIS TIME FOR THE PD. WARM AND HUMID CONDS WL CONT THRU MON MRNG WITH TEMPS AND TDS IN THE U50S/L60S. MOISTURE FM TROPICAL STORM KAREN PROGGED BY GFS TO WORK UP INTO AREA MON NGT. HWVR, THIS WL ALL DEPEND ON HOW MUCH H5 SYSTEM SLOWS DOWN AND IF FRONTAL BNDRY CAN HOLD OFF ENUF TO BRING MOISTURE INTO AREA. AS OF NOW WITH PW VALUES INCRSG TO BTWN 1.5 AND 1.75 INCHES ON MON NGT EXPECTED 12-HR QPF VALUES FM HPC WL AVG ARND 1 INCH THRU THE END OF THE SHORT TERM. FROPA LOOKS TO HV SLOWED DOWN ENUF TO OCCUR AT THE VRY TAIL END OF THE SHORT TERM. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 345 AM UPDATE... MED RNG GRIDS UPDATED WITH 00Z WPC GDNC (BLENDED WITH SOME GFS/MOS DATA) TO REFLECT A SLOWER MVMNT OF THE UPR LOW...WITH AN EXTENSION OF CHC POPS INTO MID WEEK AND MORE IN THE WAY OF CLDS DUE TO THIS SYSTEM. PREV BLO... 2 PM UPDATE... MAIN INTEREST IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR HEAVY RAIN MONDAY NIGHT. THE MAIN WEATHER PLAYERS WILL BE AN UPPER LEVEL LOW NOW OVER SE WYOMING...AND ASSOCIATED COLD FRONT OVER THE CENTRAL PLAINS. AS THESE FEATURES MOVE EAST THE SOUTHERLY FLOW OF AIR AHEAD OF THEM WILL TRANSPORT MOISTURE...SOME OF IT WILL BE WHATS LEFT OF TS KAREN...NORTHWARD INTO OUR AREA. WITH HIGH VARIANCE IN THE MODELS JUST 24 HOURS AGO...THE 12Z NAM AND GFS ARE FAIRLY SIMILAR IN SHOWING AN AREA OF STEADY RAIN ALONG AND AHEAD OF THE COLD FRONT MOVING INTO OUR AREA MONDAY EVENING. BOTH THE GFS AND WPC GUIDANCE SHOW A GENERAL 1" TO 2" RAIN ACROSS THE AREA MONDAY NIGHT...WITH ISOLATED HIGHER AMOUNTS POSSIBLE. WITH OUR RECENT STRETCH OF DRY WEATHER AND THE PROGRESSIVE NATURE OF THE FRONT (RAIN FALLING IN 12 HOURS OR LESS)...WIDESPREAD PROBLEMS ARE NOT EXPECTED AT THIS EARLY JUNCTURE. IN FACT FOR MOST THIS WILL BE A WELCOME BENEFICIAL FALL RAIN. LATER TUESDAY AND BEYOND...THE GFS IS NOW THE SLOWEST WITH THE UPPER LEVEL LOW MOVING OVER OUR AREA AND KEEPING US CLOUDY/UNSETTLED FOR ONE MORE DAY. WILL LEAN WITH WPC GUIDANCE DRYING US OUT BY TUESDAY NIGHT. HIGH PRESSURE CONTROLS THE REST OF THE PERIOD WITH QUIET WEATHER EXPECTED. && .AVIATION /13Z SATURDAY THROUGH WEDNESDAY/... FNTL BNDRY DRAPED OVER THE TWIN TIERS/NRN PA WITH LIFR/IFR TO THE N OF THE FNT. PROFILES SUGGEST THESE CONDITIONS TO CONTINUE THRU THE MID MRNG HRS...WITH ITH/ELM/BGM/SYR/AVP BLO ALT MINS AND BRIEFLY LIKELY BLO AIRPORT MINS THRU 14Z. COULD SEE SCT -SHRA THIS MRNG 14-16Z AT SYR/RME IF ACTIVITY OVER WRN NY HOLDS TOGETHER. XPCT CIGS TO SLOWLY LIFT LATE THIS MRNG/AFTN TO MVFR MOST SITES. CHCS FOR SHRA APPEAR TO BE GREATEST THIS AFTN NEAR THE FNT AND INCLUDED TEMPOS FOR SHRA AT ITH/ELM/BGM/AVP THIS AFTN. POTNL FOR TSRA ACRS SRN SITES WHICH MAY BE ADDED WITH LATER FCST UPDATES. TNGT...MVFR XPCTD TO PREVAIL THRU 06Z...WITH POTNL FOR MVFR/IFR MAINLY AFTER 06Z AS -SHRA MOV BACK IN. WINDS ON THE LGT SIDE AND RATHER VRBL...MAINLY FROM A NORTHERLY DIRECTION ACRS CNTRL NY...BECMG ERLY OR SELY TNGT. OUTLOOK... SATURDAY NIGHT THROUGH WEDNESDAY...AN UNSETTLED PERIOD...WITH SCATTERED TO WIDESPREAD SHOWERS ANTICIPATED...ALG WITH THE LIKELIHOOD OF RESTRICTIVE CONDS FROM TIME TO TIME. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM... AVIATION...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE OVER THE REGION WILL MOVE SLOWLY EAST OFFSHORE THE CAROLINA COAST TONIGHT AND SUNDAY. A COLD FRONT WILL APPROACH THE MOUNTAINS FROM THE WEST SUNDAY NIGHT...THEN TRACK EASTWARD THROUGH THE CAROLINAS ON MONDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1000 AM SATURDAY... SURFACE RIDGE REMAINS IN PLACE OVER CENTRAL NORTH CAROLINA...AND THE MORNING UPPER-AIR ANALYSIS SHOWED THE RIDGE AXIS ALOFT JUST TO OUR WEST. MORNING AMDAR SOUNDINGS AS WELL AS THE SOUNDING FROM KGSO NOTED WARMING ALOFT AROUND 600MB OVER THE LAST 24 HOURS... REPRESENTING STRONG CAPPING. THE LATEST RAP SHOWS THE RIDGE ALOFT BUILDING EAST OVERHEAD DURING THE AFTERNOON...WITH GOOD SUBSIDENCE AND LITTLE OR NO MIXED-LAYER CAPE IN THE LOWEST KM. MORNING SOUNDINGS AND THE KRAX VAD WIND PROFILE NOTED A FAIRLY DEEP...BUT LIGHT...NORTHERLY COMPONENT TO THE WIND WHICH SHOULD VEER DURING THE DAY BASED ON THE LATEST RAP AND MOS GUIDANCE. MAIN CHANGES...ALL MINOR...TO THE FORECAST FOR THE AFTERNOON WERE TO MODIFY THE DIRECTION OF THE LIGHT WIND INTO THE MID-AFTERNOON HOURS...AND NOTE JUST A FEW MORE CLOUDS WITH SOME MOSTLY THIN CIRRUS WORKING ITS WAY EAST OF THE RIDGE AXIS ALOFT. 1000-850MB THICKNESSES FROM THE KGSO 12Z SOUNDING COMBINED WITH THE FORECAST MAXIMUM VALUE OF THAT PARAMETER THIS AFTERNOON GIVES MAXES IN LINE WITH THE FORECAST. LOWS TONIGHT WILL BE SIMILAR TO THIS MORNING...IN THE LOWER/MID 60S...COOLEST IN RURAL AND LOW-LYING AREAS. EXPECT AREAS OF FOG AGAIN TONIGHT UNDER A MAINLY CLEAR SKY...LIGHT WIND...AND SURFACE DEW POINTS LATE AT NIGHT 60 TO 65. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 345 AM SATURDAY... AN IMPRESSIVE UPPER LEVEL LOW CENTERED OVER THE UPPER MIDWEST THIS MORNING WILL TRACK INTO THE CENTRAL MS RIVER VALLEY SUN INTO SUN NIGHT...WHILE ADDITIONAL SHORTWAVE ENERGY (OVER THE 4-CORNERS REGION THIS MORNING) DIGS SOUTHEAST THROUGH THE LOWER MIDWEST INTO THE LOWER MS RIVER VALLEY ALONG THE SOUTHERN PERIPHERY OF THE UPPER LOW. ADDITIONALLY...TROPICAL CYCLONE KAREN IS EXPECTED TO TRACK SLOWLY NORTH TOWARD THE GULF COAST ON SUN...MOVING ASHORE SOMEWHERE IN THE DEEP SOUTH SUN NIGHT. IN THE LOWER LEVELS...A COLD FRONT ASSOC/W AN OCCLUDED SFC LOW ATTENDANT THE UPPER LEVEL LOW WILL TRACK EAST INTO THE TN/OH VALLEY ON SUN...APPROACHING THE SOUTHERN APPALACHIANS SUN NIGHT. PER THE 00Z GUIDANCE...SOUTHERLY RETURN FLOW AND LOW-LEVEL WARM ADVECTION WILL NOT SIGNIFICANTLY STRENGTHEN UNTIL SUN NIGHT...AND THE AIRMASS ON SUNDAY IS EXPECTED TO BE VERY SIMILAR TO TODAY WITH A PRONOUNCED MID-LEVEL CAP AND MEAGER DIURNAL DESTABILIZATION (AT BEST). FORCING FOR ASCENT WILL LARGELY BE ABSENT OVER CENTRAL NC...CONFINED TO THE SEABREEZE OVER THE COASTAL CAROLINAS AND SMALL AMPLITUDE DISTURBANCES IN STRENGTHENING SW FLOW ALOFT OVER FAR WESTERN PORTIONS OF THE STATE DURING THE AFT/EVE. AS A RESULT...WILL CONTINUE TO INDICATE A DRY FCST ON SUN. A RAPID INCREASE IN LOW-LEVEL MOISTURE ASSOC/W STRENGTHENING SOUTHERLY FLOW WILL OCCUR SUN NIGHT AND MON MORNING...WITH ASCENT INCREASING IN THE FORM OF LOW-LEVEL WARM ADVECTION AND DPVA ASSOC/W SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT. ALL OF THE 00Z GUIDANCE INDICATES MEASURABLE PRECIP IN THE WESTERN PIEDMONT BY 12Z MON...AND THIS SEEMS CONSISTENT WITH THE AFOREMENTIONED DISCUSSION. WILL INDICATE PRECIP CHANCES INCREASING FROM THE WEST AFTER MIDNIGHT...RANGING FROM 60-80% IN THE FAR WESTERN PIEDMONT TO ~20% ALONG THE I-95 CORRIDOR. EAST OF I-95...FORCING FOR ASCENT WILL BE MUCH WEAKER AND PRECIP CHANCES WILL LARGELY BE TIED TO SHOWER ACTIVITY MOVING INLAND FROM THE ATLANTIC IN ASSOC/W ONSHORE FLOW. AS A RESULT...WILL INDICATE A DRY FCST IN THE FAR NE COASTAL PLAIN WITH A SLIGHT CHANCE SOUTH OF HWY 64 IN THE SE COASTAL PLAIN. THICKNESSES WILL BE SLIGHTLY LOWER (PERHAPS 5-10M) THAN TODAY. THIS...ALONG WITH INCREASING CLOUD COVER DURING THE AFTERNOON SHOULD RESULT IN HIGHS A FEW DEGREES COOLER THAN TODAY IN THE MID 80S (84-88F)...COOLEST IN THE WESTERN PIEDMONT. LOWS SUN NIGHT WILL BE TEMPERED BY CLOUD COVER AND A LIGHT SOUTHERLY BREEZE...IN THE UPPER 60S TO NEAR 70F IN THE SOUTH. -VINCENT && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... THE LATEST INFORMATION FROM THE NHC CONCERNING "KAREN" CONTINUES TO DOWNGRADE THE TROPICAL SYSTEM. IT HAS BEEN DESCRIBED AS ALREADY BEING `DECAPITATED" BY ONE FORECASTER - DUE TO STRONGER WINDS ALOFT. THEREFORE... THE CONFIDENCE OF WHETHER ANY REMNANTS OF `KAREN" WILL BE LEFT TO BRING INDIRECT IMPACTS (RAIN, SEVERE THREAT) FOR CENTRAL NC BY EARLY NEXT WEEK HAS LOWERED. ON A MORE CONFIDENT NOTE... A MID/UPPER LEVEL TROUGH IS FORECAST TO BE APPROACHING THE APPALACHIANS MONDAY... THEN SWING ACROSS OUR REGION TUE AND TUE NIGHT. THE MAIN UPPER DYNAMICS ARE FORECAST TO PUSH FROM THE MIDWEST TO THE GREAT LAKES. HOWEVER... MOISTURE IS EXPECTED TO SURGE NORTHWARD ALONG THE EASTERN SEABOARD BRINGING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE COLD FRONT. IF THE REMNANT LOW PRESSURE OF `KAREN` TRACKS NE INTO NC AS SOME OF THE MODELS STILL SUGGEST... THERE CAN STILL BE ENHANCED RAINFALL FOR 12-24 HOURS. OTHERWISE... THIS WOULD BE A TYPICAL RAINFALL EVENT ASSOCIATED WITH A MID-LATITUDE TROUGH EARLY NEXT WEEK. ONCE THE TROUGH PASSES... CLEARING AND COOLER CONDITIONS ARE EXPECTED MID THROUGH LATE WEEK. LOWS 50-55. HIGHS 70-75. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... AS OF 1000 AM SATURDAY... 24-HR TAF PERIOD: VFR CONDITIONS AND WINDS UNDER 10KT WILL PREVAIL THE REMAINDER OF THE TAF PERIOD. SURFACE WINDS MAY SHOW A NORTHERLY COMPONENT VEERING GRADUALLY SOUTH DURING THE LATE MORNING AND EARLY AFTERNOON. LATE TONIGHT...UNDER A MOSTLY CLEAR SKY...LIGHT SOUTHERLY WIND...AND PERSISTENT LATE-NIGHT SURFACE DEW POINTS FROM 60 TO 65...EXPECT AREAS OF FOG...WITH LOWEST VISIBILITIES TOWARD KFAY AND KRWI. LOOKING AHEAD: ASIDE FROM A POTENTIAL FOR FOG OR SUB-VFR CEILINGS BETWEEN 08-12Z SUNDAY MORNING...VFR CONDS ARE EXPECTED TO PREVAIL DURING THE DAY SUNDAY WITH CEILINGS SOMEWHAT LOWER THAN PREVIOUS DAYS (3500-4500 FT AGL) IN ASSOC/W THE ONSET OF A LIGHT SOUTHERLY RETURN FLOW OVER WESTERN PORTIONS OF THE STATE AS HIGH PRESSURE MOVES OFFSHORE. EXPECT AN INCREASING CHANCE FOR MVFR/IFR CEILINGS AT ALL TERMINALS IN ADVANCE OF A COLD FRONT PROGRESSING SLOWLY EAST TOWARD THE SOUTHERN APPALACHIANS SUNDAY NIGHT...ALONG WITH AN INCREASING CHANCE FOR RAIN AT THE INT/GSO TERMINALS BETWEEN 06-12Z MONDAY MORNING. EXPECT WIDESPREAD SHOWERS/STORMS DURING THE DAY MONDAY AS THE COLD FRONT TRACKS EAST INTO THE CAROLINAS. UNCERTAINTY IN THE FCST INCREASES THEREAFTER...HOWEVER...IT IS POSSIBLE THAT RAIN AND SUB-VFR CONDITIONS MAY PERSIST MONDAY NIGHT INTO TUESDAY. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...DJF/VINCENT SHORT TERM...VINCENT LONG TERM...BADGETT AVIATION...DJF/VINCENT
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1038 AM EDT SAT OCT 5 2013 .SYNOPSIS... SOUTHWEST FLOW OF WARM...MUGGY AIR CONTINUES INTO SUNDAY. COLD FRONT BRINGS SHOWERS ALONG WITH SOME STORMS LATE SUNDAY INTO MONDAY. UPPER LOW PULLS OUT MIDWEEK...YIELDING TO HIGH PRESSURE LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... A FEW SMALL WAVES EMBEDDED WITHIN THE UPPER RIDGE HAVE SPARKED SOME CONVECTION OVER THE OHIO VALLEY THIS MORNING...BUT THIS IS NOT ABLE TO GET MUCH IN TERMS OF VERTICAL EXTENT. HAD TO DRAG THE POPS A LITTLE FURTHER TO THE SOUTHEAST...BUT LEFT THEM OUT OF CRW. WILL REASSESS WHEN THE NEW MODELS ARE IN. HRRR HAS BEEN VALUABLE THIS MORNING. PREVIOUS DISCUSSION... SUMMER REPRISE CONTINUES. ALTOCU THIS MORNING AIDS IN ERADICATING THE DENSE VALLEY FOG OF EARLY MORNING...OR HOLDS IT IN IF IT SURVIVES DAWN....AND CU THIS AFTERNOON IN VERY WARM AND HUMID SW FLOW AS UPPER RIDGE MOVES E ACROSS AREA. WEAK RIPPLES IN THE UPPER LEVEL SW FLOW ONCE THE RIDGE GOES BY COULD GRAZE NW PORTION OF AREA WITH CONVECTION MIDDAY TODAY INTO THIS EVENING. FLOW GOES MORE SOUTHERLY TONIGHT...SO CONVECTION ASSOCIATED WITH RIPPLES IN FLOW WILL SHIFT N OF THE AREA WHILE THAT ASSOCIATED WITH COLD FRONT TO THE W REMAINS W OF THE AREA THROUGH 12Z SUN. ALTOCU LIMITED TO THE W. BOUNDARY LATER FLOW SHOULD PRECLUDE DENSE VALLEY FOG SAVE FOR THE DEEPER VALLEYS OF EASTERN WV LATE TONIGHT. ROLLED WITH BIAS CORRECTED ADJMET AND BIAS CORRECTED ALL BLEND TOGETHER WITH PREVIOUS FOR HIGHS TODAY WITH ADJMAV BEING TOO HIGH. LOWER TO MID 80S LOWLANDS IS 5-10F BELOW RECORD HIGHS. DID BLEND IN BIAS CORRECTED ADJMAV FOR LOWS TONIGHT...A TICK OR SO HIGHER THAN PREVIOUS ON RIDGE/HILL TOPS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... UNSETTLED WEATHER IN THE SHORT TERM PERIOD. RATHER WARM AND HUMID DAY ON TAP SUNDAY...AS UPPER LOW ACROSS CENTRAL U.S. DIGS SOUTH AND EAST...CAUSING FLOW TO BACK...AND SLOWING THE PROGRESSION OF THE COLD FRONT AND ASSOCIATED PRECIPITATION INTO THE CWA. STILL EXPECTING SOME DECENT RAINFALL TOTALS...AS LLJ AIDS IN MOISTURE TRANSPORT TO THE REGION...WITH PW VALUES EXPECTED TO RISE TO 1.6 TO 1.7 INCHES. AS WITH PREVIOUS FORECASTER...WILL LEAVE A MENTION OF WATER PROBLEMS OUT OF THE HWO DUE TO RECENT DRY SPELL...AND OVERALL PROGRESSIVE NATURE OF THE SYSTEM. IN ADDITION...AT THIS POINT...SPC HAS ISSUED ONLY A SEE TEXT AREA FOR THE CWA...AS CLOUD COVER...AND OVERALL LACK OF INSTABILITY SHOULD HOPEFULLY LIMIT THE SEVERE POTENTIAL ACROSS THE REGION. STILL...EXPECTING SOME RATHER GUSTY CONDITIONS ASSOCIATED WITH FRONTAL PASSAGE...SET TO TAKE PLACE ON MONDAY...PARTICULARLY ACROSS HIGHER ELEVATIONS. HOWEVER...THIS WILL NEED TO BE MONITORED AS MODELS ARE INDICATING STRONG FORCING WITH THE FRONT. MODELS CONTINUE TO INDICATE THAT REMNANTS OF KAREN WILL REMAIN FAR ENOUGH TO THE EAST OF THE AREA...THAT THE CWA WILL SEE LITTLE TO NO EFFECT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... LOOKING AT UPR RIDGE TO BUILD ACROSS EASTERN CONUS IN THE EXTENDED WITH STALLED SFC FRONT LINGERING ALONG E COAST. SEASONABLE TEMPS DURING THE DAY AND COOL NIGHTS ON TAP. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... FOG WAS MORE LIMITED EARLY THIS MORNING COMPARED WITH FRI MORNING AND WILL BE EVEN MORE LIMITED SUN MORNING GIVEN ANOTHER DAY OF LOW SHOWER/THUNDERSTORM COVERAGE...AND SOMEWHAT INCREASED BOUNDARY LAYER FLOW. AS FOR THIS MORNING...THE FOG WILL FINISH THINNING OUT 13-14Z. CIRRUS AND ALTOCU MOVING ACROSS THIS MORNING FOLLOWED BY A BUILDING CU FIELD THIS AFTERNOON. SHOWERS AND THUNDERSTORMS COULD AFFECT THE MIDDLE OHIO VALLEY MIDDAY TODAY INTO THIS EVENING. AN ISOLATED SHOWER OR THUNDERSTORM COULD ALSO POP UP OVER THE NORTHERN WV MOUNTAINS THIS AFTERNOON. LIGHT AND VARIABLE SFC FLOW TODAY BECOMES LIGHT S TO SE TONIGHT WHILE LIGHT NW FLOW ALOFT SWITCHES TO LIGHT SW THIS MORNING AND THEN BECOMES LIGHT S TO SW TONIGHT. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY... FORECAST CONFIDENCE: HIGH. ALTERNATE SCENARIOS: LITTLE MORE THEN MINOR VARIATIONS ARE EXPECTED IN THE FCST. 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 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L 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 H H H H H H H H H H H H AFTER 12Z SUNDAY... IFR POSSIBLE ALONG COLD FRONT...MOVING W TO E...SUN NT INTO MON...AND IN POST-RAIN FOG/STRATUS TUE MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM/26 SHORT TERM...SL LONG TERM...30 AVIATION...TRM
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1021 AM CDT SAT OCT 5 2013 .DISCUSSION... THE COLD FRONT WAS PROGRESSING STEADILY ACROSS THE NORTHERN AND CENTRAL PORTIONS OF THE STATE. UPDATED THE WIND SHIFT WITH THE LATEST RAP FORECAST. A 12Z ANALYSIS SHOWED A SURFACE RIDGE OVER THE TEXAS COASTAL AREAS WITH LOW-LEVEL MOISTURE STREAMING NORTHWARD FROM THE GULF INTO AREAS MAINLY EAST OF FREEPORT. OVER MOST OF THE FORECAST AREA THE AIR MASS WAS FAIRLY DRY AND CAPPED AND EXPECT THAT MOST CONVECTION THIS AFTERNOON WILL BE CONFINED TO THE EASTERN AND NORTHERN SET OF COUNTIES WHERE THE DEEPER MOISTURE AND COOLER AIRMASS ALOFT RESIDES. WILL UPDATE MAINLY FOR THE WINDS. OTHERWISE...THE REMAINDER OF THE FORECAST LOOKS ON TARGET. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 89 58 81 52 83 / 20 20 10 0 0 HOUSTON (IAH) 92 62 80 53 83 / 50 30 10 0 0 GALVESTON (GLS) 89 69 81 65 80 / 40 30 20 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$ DISCUSSION...40 AVIATION/MARINE...47
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1017 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. A LOW PRESSURE SYSTEM TRACKING FROM THE CENTRAL PLAINS TO THE GREAT LAKES WILL PUSH A STRONG COLD FRONT THROUGH THE AREA ON MONDAY. THE LOW AND COLD FRONT WILL MOVE OFFSHORE BY TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 945 AM EDT SATURDAY... SHOULD BE A WARM...POTENTIALLY RECORD BREAKING DAY...ESPECIALLY AT BLACKSBURG/BLUEFIELD (SEE CLIMATE SECTION BELOW)...AS HIGH PRESSURE RESIDES OVERHEAD. FOG WILL BE LIFTING ACROSS THE VALLEYS...BUT HAS HELD STRONG IN THE GREENBRIER VALLEY. TEMPS STARTING TO RUN A COUPLE DEGREES WARMER OUT EAST THAN CURRENT FORECAST...SO BUMPED UP HIGHS A COUPLE DEGREES...LOOKING AT UPPER 70S TO LOWER 80S ACROSS THE HIGHER TERRAIN...TO MID TO UPPER 80S VALLEYS AND POINTS EAST OF THE BLUE RIDGE. PREVIOUS VALID DISCUSSION... SURFACE HIGH PRESSURE AND A 500 MB RIDGE WILL REMAIN OVER THE CENTRAL AND SOUTHERN APPALACHIANS THROUGH TONIGHT. LOCAL WRF AS WELL AS HRRR AND LATEST RAP GUIDANCE SUGGEST THERE IS STILL A LOW CHANCE OF SHOWERS THIS AFTERNOON...MAINLY NORTH OF I-64. ASIDE FROM THE WEST TO SOUTHWEST UPSLOPE WINDS...LITTLE IN THE WAY OF SHORT WAVES TO HELP TRIGGER ANY PRECIPITATION. ANY SCATTERED TO BROKEN CU THAT DEVELOPS TODAY WILL DISSIPATE THIS EVENING. USED A BLEND OF BIAS CORRECTED MAV/MET GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 453 AM EDT SATURDAY... MODELS REMAINING CONSISTENT WITH MOVING A COLD FRONT AND ASSOCIATED SHOWERS INTO THE OHIO VALLEY ON SUNDAY. MODELS HAVE SLOWED DOWN THE FRONTS MOVEMENT INTO THE AREA SUNDAY NIGHT AND ACROSS THE REGION MONDAY/MONDAY NIGHT. THE SLOWER PROGRESSION OF THE FRONT IS DUE TO UPPER LEVEL FORCING BECOMING DETACHED FROM THE LOW LEVEL BOUNDARY. TROPICAL STORM KAREN OR REMNANTS OF...MAY ALSO PLAYING A PART IN SLOWING THE FRONT DOWN TO A CRAWL AS IT CROSSES OVER THE AREA. BASED ON THE 00Z MODEL TRENDS...LOWERED POPS INTO SUNDAY EVENING. MEASURABLE RAIN BEGINS TO TRACK ACROSS THE SOUTHWEST EARLY MONDAY MORNING...THEN SPREADS ACROSS THE REST OF THE MOUNTAINS AROUND SUNRISE. RAIN CHANCES INCREASE EAST OF THE BLUE RIDGE TOWARD THE AFTERNOON AND CONTINUES INTO THE EVENING. WITH A COLD FRONT INTERACTING WITH TROPICAL MOISTURE...IT WAS A NO BRAINER TO INCREASE POPS TO 100 PERCENT MONDAY. WITH THE FRONT BEING SLOWER...ALSO INCREASED POPS MONDAY EVENING...TRENDING DOWN TUESDAY MORNING AS THE FRONT TRACKS EAST. WITH SHOWERS NOT DUE TO MOVE ACROSS THE PIEDMONT UNTIL THE AFTERNOON...THERE MAY BE ENOUGH INSTABILITIES TO GENERATE A RUMBLE OF THUNDER. IF ENOUGH INSTABILITIES IS PRESENT WHEN THE 850 JET PASSES OVERHEAD...A STORM OR TWO MAY PRODUCE STRONG WINDS. FOR THE MOST PART...THIS WILL BE A HYDRO EVENT. PWATS ON MONDAY APPROACH 2 INCHES WHICH IS CLOSE TO BEING 2 STANDARD DEVIATIONS ABOVE NORMAL. RAINFALL AMOUNTS FROM SUNDAY NIGHT INTO MONDAY EVENING SHOULD RANGE FROM 1 TO 2 INCHES. WITH THE RECENT DRY SPELL...THE FORECAST AREA SHOULD NOT SEE ANY WIDESPREAD WATER PROBLEMS. LOCALIZE FLOODING IS NOT OUT OF THE QUESTION IN POOR DRAINAGE AREAS...ESPECIALLY IF HIGH RAINFALL RATES OR TRAINING OF STORMS PERSIST OVER AN AREA FOR SEVERAL HOURS. THE UPPER LEVEL RIDGE THAT BROUGHT WARMTH TO THE AREA ON SATURDAY WILL BEGIN TO SLIDE OFF THE SOUTHEAST COAST ON SUNDAY. WITH THE FRONT REMAINING WEST OF THE AREA FOR MOST OF SUNDAY...WARMER THAN NORMAL TEMPERATURES WILL AGAIN COVER THE REGION. SUNDAY TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S ACROSS THE WEST TO MID TO UPPER 80S IN THE EAST. A DRAMATIC COOL DOWN COMES MONDAY WITH THE RAIN. FORECASTED HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE WEST TO LOWER 70S ACROSS THE PIEDMONT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 1215 PM EDT FRIDAY... FORECAST EARLY IN THE PERIOD CENTERS AROUND THE FRONT/REMNANTS OF KAREN AND THE UPPER TROUGH MOVING ACROSS THE GREAT LAKES/NORTHEAST/MID ATLANTIC. THE LATEST GFS (12Z) CONTINUES TO BE SLOWER...AND IS ACTUALLY SLOWER THAN THE 06Z RUN IN MOVING THE FRONT OUT...WITH A STRONGER UPPER LOW...BUT IS FURTHER EAST WITH KAREN. PER NHC/WPC...WILL BE LEANING TOWARD THE 00Z ECMWF AND THE PREVIOUS FORECAST. THERE WILL STILL BE LINGERING SHOWERS ACROSS THE PIEDMONT TUESDAY AND NOT OUT OF THE QUESTION THAT STRONG SUBSIDENCE BEHIND THE DEPARTING TROPICAL SYSTEM MAY START TO DRY THINGS OUT FASTER. FOR MID TO LATE WEEK...THE FORECAST MAINTAINS A CHALLENGE IN TERMS OF SFC HIGH PRESSURE WEDGING SOUTH INTO OUR AREA...WHILE A RESIDUAL UPPER TROUGH LINGERS OVER THE SOUTHEAST. QUESTION WILL BE WHERE DEEPER MOISTURE RESIDES. WITH THE ECMWF THINK MOST OF THE CLOUD COVER WILL BE HUGGING OUR SOUTHEAST CWA WITH MORE RESIDING ACROSS THE SOUTHEAST...WHILE THE WESTERN CWA SEES MORE SUN DURING THE DAY. TEMPERATURES GIVEN A LIGHT NE-E FLOW WILL BE CLOSER TO NORMAL...WITH THE THREAT OF RAIN BEING LESS THAN 10 PERCENT. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/... AS OF 740 AM EDT SATURDAY... NEW RIVER AND GREENBRIER VALLEYS HAD DENSE FOG THIS MORNING... INCLUDING LIFR VISIBILITIES AT KBCB AND KLWB. EXPECT IMPROVEMENT IN CONDITIONS BY 10AM. ONCE FOG MIXES OUT THIS MORNING...HIGH CONFIDENCE THAT THE REST OF THE DAY WILL BE VFR. HAVE ADDED FOG IN AGAIN FOR TONIGHT IN KLWB AND KBCB, WITH DEW POINTS GRADUALLY RISING...THERE IS A POSSIBILITY FOR MVFR FOG AT KDAN AND KLYH AFTER 06Z2AM TONIGHT. MID AND HIGH LEVEL CLOUDS WILL ARRIVE SUNDAY THOUGH AS THE COLD FRONT ENTERS THE OHIO VALLEY. OUR NEXT CHANCE FOR WIDESPREAD AND PROLONGED SUB-VFR CONDITIONS WILL COME SUNDAY NIGHT INTO MONDAY WHEN A COLD FRONT APPROACHES FROM THE WEST...AND WHAT IS LEFT OF TROPICAL CYCLONE KAREN RIDES NORTH THROUGH OR NEAR OUR REGION IN ADVANCE OF IT. THIS WOULD ALLOW A TREND TOWARD DECREASING CEILING HEIGHTS AND INCREASED COVERAGE OF RAIN. VISIBILITIES WOULD TREND LOWER AS WELL...ESPECIALLY SUNDAY INTO MONDAY AS PRECIPITATION INTENSIFIES AND FOG POTENTIAL INCREASES. RAIN ENDS MONDAY NIGHT BUT THERE STILL MAY BE RESTRICTIONS IN CEILING AND VISIBILITY AS PRECIP COULD STILL BE HEAVY ACROSS THE VA/NC PIEDMONT WITH POTENTIALLY SOME FOG ACROSS SE WEST VA. A DRIER PATTERN IS EXPECTED TUESDAY AND WEDNESDAY WITH MORNING FOG. && .CLIMATE... RECORD HIGH TEMPS FOR SATURDAY. ROANOKE 98/1941 LYNCHBURG 96/1941 DANVILLE 98/1951 BLACKSBURG 86/1954 BLUEFIELD 85/2007 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/WP NEAR TERM...AMS/WP SHORT TERM...RCS LONG TERM...JH/WP AVIATION...AMS/KK/KM CLIMATE...RCS
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
746 AM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY AND TONIGHT. A LOW PRESSURE SYSTEM TRACKING FROM THE CENTRAL PLAINS TO THE GREAT LAKES WILL PUSH A STRONG COLD FRONT THROUGH THE AREA ON MONDAY. THE LOW AND COLD FRONT WILL MOVE OFFSHORE BY TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 345 AM EDT SATURDAY... SURFACE HIGH PRESSURE AND A 500 MB RIDGE WILL REMAIN OVER THE CENTRAL AND SOUTHERN APPALACHIANS TODAY AND TONIGHT. LOCAL WRF AS WELL AS HRRR AND LATEST RAP GUIDANCE SUGGEST THERE IS STILL A LOW CHANCE OF SHOWERS THIS AFTERNOON...MAINLY NORTH OF I-64. ASIDE FROM THE WEST TO SOUTHWEST UPSLOPE WINDS...LITTLE IN THE WAY OF SHORT WAVES TO HELP TRIGGER ANY PRECIPITATION. DEEP SOUTHWEST WINDS THIS AFTERNOON...EVEN THOUGH WIND SPEEDS WILL NOT BE VERY STRONG...WILL PROVIDE SOME DOWNSLOPNIG AND COMPRESSION. COMBINED WITH 850 MB TEMPERATURES OF +16 TO +18...MAXIMUM TEMPERATURES WILL AGAIN BE WELL ABOVE NORMAL. EXPECTING SIMILAR TEMPERATURES COMPARED TO FRIDAY...AND POSSIBLY A DEGREE OR TWO HIGH AS LONG AS THERE IS NOT CLOUD COVER. ANY SCATTERED TO BROKEN STRATOCUMULUS THAT DEVELOPS TODAY WILL DISSIPATE THIS EVENING. USED A BLEND OF BIAS CORRECTED MAV/MET GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 453 AM EDT SATURDAY... MODELS REMAINING CONSISTENT WITH MOVING A COLD FRONT AND ASSOCIATED SHOWERS INTO THE OHIO VALLEY ON SUNDAY. MODELS HAVE SLOWED DOWN THE FRONTS MOVEMENT INTO THE AREA SUNDAY NIGHT AND ACROSS THE REGION MONDAY/MONDAY NIGHT. THE SLOWER PROGRESSION OF THE FRONT IS DUE TO UPPER LEVEL FORCING BECOMING DETACHED FROM THE LOW LEVEL BOUNDARY. TROPICAL STORM KAREN OR REMNANTS OF...MAY ALSO PLAYING A PART IN SLOWING THE FRONT DOWN TO A CRAWL AS IT CROSSES OVER THE AREA. BASED ON THE 00Z MODEL TRENDS...LOWERED POPS INTO SUNDAY EVENING. MEASURABLE RAIN BEGINS TO TRACK ACROSS THE SOUTHWEST EARLY MONDAY MORNING...THEN SPREADS ACROSS THE REST OF THE MOUNTAINS AROUND SUNRISE. RAIN CHANCES INCREASE EAST OF THE BLUE RIDGE TOWARD THE AFTERNOON AND CONTINUES INTO THE EVENING. WITH A COLD FRONT INTERACTING WITH TROPICAL MOISTURE...IT WAS A NO BRAINER TO INCREASE POPS TO 100 PERCENT MONDAY. WITH THE FRONT BEING SLOWER...ALSO INCREASED POPS MONDAY EVENING...TRENDING DOWN TUESDAY MORNING AS THE FRONT TRACKS EAST. WITH SHOWERS NOT DUE TO MOVE ACROSS THE PIEDMONT UNTIL THE AFTERNOON...THERE MAY BE ENOUGH INSTABILITIES TO GENERATE A RUMBLE OF THUNDER. IF ENOUGH INSTABILITIES IS PRESENT WHEN THE 850 JET PASSES OVERHEAD...A STORM OR TWO MAY PRODUCE STRONG WINDS. FOR THE MOST PART...THIS WILL BE A HYDRO EVENT. PWATS ON MONDAY APPROACH 2 INCHES WHICH IS CLOSE TO BEING 2 STANDARD DEVIATIONS ABOVE NORMAL. RAINFALL AMOUNTS FROM SUNDAY NIGHT INTO MONDAY EVENING SHOULD RANGE FROM 1 TO 2 INCHES. WITH THE RECENT DRY SPELL...THE FORECAST AREA SHOULD NOT SEE ANY WIDESPREAD WATER PROBLEMS. LOCALIZE FLOODING IS NOT OUT OF THE QUESTION IN POOR DRAINAGE AREAS...ESPECIALLY IF HIGH RAINFALL RATES OR TRAINING OF STORMS PERSIST OVER AN AREA FOR SEVERAL HOURS. THE UPPER LEVEL RIDGE THAT BROUGHT WARMTH TO THE AREA ON SATURDAY WILL BEGIN TO SLIDE OFF THE SOUTHEAST COAST ON SUNDAY. WITH THE FRONT REMAINING WEST OF THE AREA FOR MOST OF SUNDAY...WARMER THAN NORMAL TEMPERATURES WILL AGAIN COVER THE REGION. SUNDAY TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S ACROSS THE WEST TO MID TO UPPER 80S IN THE EAST. A DRAMATIC COOL DOWN COMES MONDAY WITH THE RAIN. FORECASTED HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE WEST TO LOWER 70S ACROSS THE PIEDMONT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 1215 PM EDT FRIDAY... FORECAST EARLY IN THE PERIOD CENTERS AROUND THE FRONT/REMNANTS OF KAREN AND THE UPPER TROUGH MOVING ACROSS THE GREAT LAKES/NORTHEAST/MID ATLANTIC. THE LATEST GFS (12Z) CONTINUES TO BE SLOWER...AND IS ACTUALLY SLOWER THAN THE 06Z RUN IN MOVING THE FRONT OUT...WITH A STRONGER UPPER LOW...BUT IS FURTHER EAST WITH KAREN. PER NHC/WPC...WILL BE LEANING TOWARD THE 00Z ECMWF AND THE PREVIOUS FORECAST. THERE WILL STILL BE LINGERING SHOWERS ACROSS THE PIEDMONT TUESDAY AND NOT OUT OF THE QUESTION THAT STRONG SUBSIDENCE BEHIND THE DEPARTING TROPICAL SYSTEM MAY START TO DRY THINGS OUT FASTER. FOR MID TO LATE WEEK...THE FORECAST MAINTAINS A CHALLENGE IN TERMS OF SFC HIGH PRESSURE WEDGING SOUTH INTO OUR AREA...WHILE A RESIDUAL UPPER TROUGH LINGERS OVER THE SOUTHEAST. QUESTION WILL BE WHERE DEEPER MOISTURE RESIDES. WITH THE ECMWF THINK MOST OF THE CLOUD COVER WILL BE HUGGING OUR SOUTHEAST CWA WITH MORE RESIDING ACROSS THE SOUTHEAST...WHILE THE WESTERN CWA SEES MORE SUN DURING THE DAY. TEMPERATURES GIVEN A LIGHT NE-E FLOW WILL BE CLOSER TO NORMAL...WITH THE THREAT OF RAIN BEING LESS THAN 10 PERCENT. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... AS OF 740 AM EDT SATURDAY... NEW RIVER AND GREENBRIER VALLEYS HAD DENSE FOG THIS MORNING... INCLUDING LIFR VISIBILITIES AT KBCB AND KLWB. EXPECT IMPROVEMENT IN CONDITIONS BY 10AM. ONCE FOG MIXES OUT THIS MORNING...HIGH CONFIDENCE THAT THE REST OF THE DAY WILL BE VFR. HAVE ADDED FOG IN AGAIN FOR TONIGHT IN KLWB AND KBCB, WITH DEW POINTS GRADUALLY RISING...THERE IS A POSSIBILITY FOR MVFR FOG AT KDAN AND KLYH AFTER 06Z2AM TONIGHT. MID AND HIGH LEVEL CLOUDS WILL ARRIVE SUNDAY THOUGH AS THE COLD FRONT ENTERS THE OHIO VALLEY. OUR NEXT CHANCE FOR WIDESPREAD AND PROLONGED SUB-VFR CONDITIONS WILL COME SUNDAY NIGHT INTO MONDAY WHEN A COLD FRONT APPROACHES FROM THE WEST...AND WHAT IS LEFT OF TROPICAL CYCLONE KAREN RIDES NORTH THROUGH OR NEAR OUR REGION IN ADVANCE OF IT. THIS WOULD ALLOW A TREND TOWARD DECREASING CEILING HEIGHTS AND INCREASED COVERAGE OF RAIN. VISIBILITIES WOULD TREND LOWER AS WELL...ESPECIALLY SUNDAY INTO MONDAY AS PRECIPITATION INTENSIFIES AND FOG POTENTIAL INCREASES. RAIN ENDS MONDAY NIGHT BUT THERE STILL MAY BE RESTRICTIONS IN CEILING AND VISIBILITY AS PRECIP COULD STILL BE HEAVY ACROSS THE VA/NC PIEDMONT WITH POTENTIALLY SOME FOG ACROSS SE WEST VA. A DRIER PATTERN IS EXPECTED TUESDAY AND WEDNESDAY WITH MORNING FOG. && .CLIMATE... RECORD HIGH TEMPS FOR SATURDAY. ROANOKE 98/1941 LYNCHBURG 96/1941 DANVILLE 98/1951 BLACKSBURG 86/1954 BLUEFIELD 85/2007 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS NEAR TERM...AMS SHORT TERM...RCS LONG TERM...JH/WP AVIATION...AMS/KK/KM CLIMATE...RCS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
634 AM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 523 AM CDT SAT OCT 5 2013 WITH CONVECTION SHIFTING EAST AND LACK OF OVERALL ACTIVITY EXPECTED THROUGH THE NEXT SEVERAL HOURS...HAVE TRENDED THE MORNING MUCH DRIER. ONLY ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THE MORNING...RAMPING UP TOWARD AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 413 AM CDT SAT OCT 5 2013 MOST EFFORT THIS FORECAST SHIFT WAS PUT TOWARD GETTING THE NEXT 24 HOURS AS ACCURATE AS POSSIBLE. SCREAMING MESSAGE IS THE SLOWER EASTWARD PROGRESSION OF THE FRONT AND INSTABILITY...MAKING FOR A BIT HIGHER SEVERE WEATHER CHANCE IN WI TODAY. WATER VAPOR SHOWING THE MONSTER LOW THAT BROUGHT 25-45 INCHES OF SNOW TO SD OVER CENTRAL SD AT 08Z AND NEARLY STATIONARY. OCCLUDED FRONT CURRENTLY POSITIONED FROM KRWF TO KCCY...WHERE THE TRIPLE POINT IS LOCATED. THE WARM FRONT EXTENDS EAST FROM NEAR KCCY TO THE DELLS IN WI...WITH THE SURFACE COLD FRONT RUNNING SOUTH FROM KCCY. THIS WARM FRONT IS THE LEADING EDGE OF THE HIGHER DEWPOINT AIR...MIDDLE 60S...AND THE ENERGY FOR THIS AFTERNOONS STORMS. THE OVERNIGHT CONVECTION HAS NOW PASSED OFF TO THE EAST...AND WITH IT THE FLASH FLOOD THREAT. EVALUATING THE 04.00Z MODEL GUIDANCE...THE TREND IS SLOWER WITH THE NORTHEAST PROGRESSION OF THE OCCLUDED/COLD FRONT. THIS ALLOWS MORE OF THE FORECAST AREA IN WI TO BE PRE-FRONTAL AND IN THE WARM SECTOR FOR A HIGHER PROBABILITY OF SEVERE WEATHER. AS THE DAY PROGRESSES...QVECTOR CONVERGENCE WILL INCREASE AS A SHORTWAVE TROUGH IN COLORADO ROTATES AROUND THE LARGER SD TROUGH AND BEGINS ITS EASTWARD PROGRESSION. AS THE FORCING BEGINS TO INCREASE...NEAR/POST FRONTAL SHOWERS WILL LIKELY DEVELOP MUCH LIKE SEEN ON RADAR ALONG I-35 EARLY THIS MORNING. ALSO...BETTER UPPER LEVEL FORCING WILL BEGIN TO WORK TOWARD THE WARM SECTOR AND WORK WITH 0-2KM THETA-E CONVERGENCE ALONG THE FRONT. INSTABILITY IN THE WARM SECTOR WILL HIGHLY DEPEND ON THE EXTENT OF THE SHOWERS AND CLOUDS OVER WI...HOWEVER BECAUSE THE DEWPOINTS ARE ALREADY MIDDLE 60S...AT LEAST MARGINAL INSTABILITY WILL BE PRESENT BY 18Z. MUCAPES AROUND 1000-1500 J/KG LOOK TO BE A GOOD ESTIMATE ON AFTERNOON CAPE...POSSIBLY HIGHER WITH MORE CLOUD BREAKS. WIND SHEAR LOOKS TO INCREASE TODAY BUT RIGHT ON THE COLD/OCCLUDED FRONTAL BOUNDARY...TO MAKE IT A MARGINAL SUPERCELL DAY WITH MULTI-CELLS ALSO PRESENT. THE 05.06Z NAM AND 05.07Z RAP BOTH SUGGEST NEAR 40 KTS OF 0-6KM SHEAR...CERTAINLY ENOUGH FOR SUPERCELLS. THE 05.07Z RAP MIXES ALL THE PRE-FRONTAL SURFACE WINDS TO SOUTHERLY. THE 05.06Z NAM AND LATEST HRRR RUNS ARE VERY AGREEABLE THAT THE WARM FRONT WILL SHIFT NORTH TO ABOUT BLACK RIVER FALLS WI TODAY...VERY CLOSE TO THE SPC DAY 1 NORTHERN EXTENT OF THE SLIGHT RISK. EASTERLY FLOW IS FOUND NORTH OF THE WARM FRONT...WHICH EXTENDS TO THE EAST TOWARD KGRB...SO A GOOD CONVERGENT BOUNDARY. WHILE TORNADO PROBABILITIES DONT LOOK HIGH...THE TRIPLE POINT AREA AND ALONG THAT WARM FRONT THIS AFTERNOON WILL BE A FOCAL POINT. OTHERWISE...DAMAGING WIND SEGMENTS OR LARGE HAIL ARE THE MAIN THREATS FROM THE STORMS IN WI. NORTH OF THE WARM FRONT...LOW-LEVEL INVERTED CONDITIONS AND ELEVATED STORMS ARE FAVORED...HEAVY RAIN IS THE MAIN THREAT...WITH AN ISOLATED HAIL STORM POSSIBLE. THE FRONT SHOULD SHIFT EAST OF THE FORECAST AREA BY EARLY EVENING WITH STRONG DEWPOINT DECREASES. THUS...THE MAIN SEVERE WEATHER THREAT LOOKS TO BE ABOUT 1 PM TO 5 PM. BY TONIGHT...THE NE AND EASTERNMOST FORECAST AREA MAY STILL HAVE SOME RAIN REMAINING. HAVE SLOWED THAT SLIGHTLY FROM THE PREVIOUS FORECAST. A DECREASING TREND OCCURS THROUGH THE EVENING AS WEATHER SHIFTS EAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 413 AM CDT SAT OCT 5 2013 THE LATEST MODEL CONSENSUS IS TO NOW KEEP THE DEFORMATION ASSOCIATED WITH THE CYCLONIC MOIST FLOW WRAPPING AROUND THE LOW TO THE WEST-NORTHWEST ON SATURDAY. THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE LOW WHICH IS A BIT FURTHER SOUTH IN THE LATEST GUIDANCE. IN ANY CASE...CHANGES WERE MADE TO SUNDAY TO TRY AND DRY IT OUT WITH THE RAIN SHOWERS JUST WEST OF THE AREA. ALTHOUGH THE CONSENSUS OF THE MODELS IS TO BRING THAT BAND INTO THE FORECAST AREA FOR MONDAY NOW...THE LATEST 05.00Z ECMWF IS MUCH MORE PROGRESSIVE AND RAPIDLY SHIFTS THE SHOWERS EAST. HAVE A SMALL CHANCE OF SHOWERS TO ADDRESS THAT SITUATION. THE REMAINDER OF THE PERIOD IS DOMINATED BY DRY WEATHER UNDER && .AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING) ISSUED AT 634 AM CDT SAT OCT 5 2013 COLD/OCCLUDED FRONT CONTINUED TO WORK ITS WAY INTO AND ACROSS THE FCST AREA EARLY THIS MORNING. AS OF 11Z IT WAS NEAR A KOWA-KAUM-KOLZ LINE. SOUTHWEST OF THIS BOUNDARY CONDITIONS WERE GENERALLY GOOD VFR WITH ONLY ISOLATED -SHRA. NORTHEAST OF THE BOUNDARY...CIGS WERE HIGHLY VARIABLE RANGING FROM LIFR TO VFR. CIGS GENERALLY IMPROVED BEHIND CLUSTERS OF CONVECTION OVERNIGHT...THEN DROPPING BACK DOWN A COUPLE HOURS LATER. FRONT MAKING SLOW PROGRESS AND VARYING TIMING SOLUTIONS AMONG THE MODELS...BUT APPEARS FRONT/BOUNDARY WILL LIFT NORTHEAST OF KRST AROUND 14Z AND KLSE AROUND 19Z. WITH FRONT PAST KRST AROUND 14Z...CONVECTION CHANCES DIMINISH FOR THE DAY AND ONLY CARRIED VCSH IN THE 17-20Z TIME-FRAME. WITH FRONT NEAR KLSE AT MID-DAY AND PEAK HEATING...CONTINUED A -SHRA/VCSH MENTION IN THE MAINLY 19-22Z PERIOD. BOUNDARY CONTINUES LIFTING NORTHEAST LATE THIS AFTERNOON/TONIGHT WITH FALLING DEW POINTS AND A DRIER AIRMASS SPREADING ACROSS THE AREA. TREND FOR ONLY SCT CLOUDS TONIGHT CONTINUES TO LOOK GOOD. GIVEN THE RECENT RAINS...WILL HAVE TO WATCH VALLEY LOCATIONS FOR BR/FG LATE TONIGHT IF SKIES DO END UP MOSTLY CLEAR AND THE VALLEY WINDS DECOUPLE. APPEARS TO BE ENOUGH GRADIENT WINDS LATER TONIGHT AND LEFT ANY BR/FG MENTION AFTER 09Z OUT OF KLSE FOR NOW. && .HYDROLOGY... ISSUED AT 413 AM CDT SAT OCT 5 2013 CONCERNING THE FLASH FLOOD WATCH...WITH CURRENT CONVECTION EAST OF THE AREA...MAIN THREAT HAS DIMINISHED. AS AFTERNOON CONVECTION INCREASES...IT SHOULD BE AFFECTING AREAS THAT HAVE HAD LESS RAIN OVERALL THAN THOSE WEST OF THE MISS RIVER. AREAS EAST OF THE MISS RIVER CAN TAKE ANOTHER 1-2 INCHES...ESPECIALLY SWRN WI. THERE IS A SMALL PROBABILITY OF LOCALIZED FLASH FLOODING TODAY IN THE CENTRAL WI CORRIDOR IN THE PRE-FRONTAL AIR MASS WHICH WILL STILL HAVE 1.25 TO 1.75 INCH PRECIPITABLE WATER VALUES. RAIN RATES ARE EXPECTED TO BE HIGH...PROBABLY 2 TO 3 INCH PER HOUR SHOULD CAPE DEVELOP AS FORECAST. THE SLOW MOVEMENT OF THE FRONT DOES GIVE SOME CONCERN FOR FLOODING SO WILL ISSUE ANOTHER HYDROLOGICAL DISCUSSION FOR THAT AREA AND CANCEL THE FLASH FLOOD WATCH. THERE ARE SOME RIVER RESPONSES CURRENTLY OCCURRING. MONITORING THE ROOT RIVER BASIN AND THE UPPER IOWA RIVERS BOTH HAVE RESPONSES. ALSO THE WHITEWATER RIVER MIDDLE FORK THAT RUNS THROUGH WHITEWATER STATE PARK IS RISING. AT THIS TIME THESE WILL APPROACH FLOOD STAGE BUT IT IS BELIEVED THEY WILL NOT REACH IT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE.......BAUMGARDT SHORT TERM...BAUMGARDT LONG TERM....BAUMGARDT HYDROLOGY....BAUMGARDT AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
525 AM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 523 AM CDT SAT OCT 5 2013 WITH CONVECTION SHIFTING EAST AND LACK OF OVERALL ACTIVITY EXPECTED THROUGH THE NEXT SEVERAL HOURS...HAVE TRENDED THE MORNING MUCH DRIER. ONLY ISOLATED SHOWERS AND THUNDERSTORMS THROUGH THE MORNING...RAMPING UP TOWARD AFTERNOON. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 413 AM CDT SAT OCT 5 2013 MOST EFFORT THIS FORECAST SHIFT WAS PUT TOWARD GETTING THE NEXT 24 HOURS AS ACCURATE AS POSSIBLE. SCREAMING MESSAGE IS THE SLOWER EASTWARD PROGRESSION OF THE FRONT AND INSTABILITY...MAKING FOR A BIT HIGHER SEVERE WEATHER CHANCE IN WI TODAY. WATER VAPOR SHOWING THE MONSTER LOW THAT BROUGHT 25-45 INCHES OF SNOW TO SD OVER CENTRAL SD AT 08Z AND NEARLY STATIONARY. OCCLUDED FRONT CURRENTLY POSITIONED FROM KRWF TO KCCY...WHERE THE TRIPLE POINT IS LOCATED. THE WARM FRONT EXTENDS EAST FROM NEAR KCCY TO THE DELLS IN WI...WITH THE SURFACE COLD FRONT RUNNING SOUTH FROM KCCY. THIS WARM FRONT IS THE LEADING EDGE OF THE HIGHER DEWPOINT AIR...MIDDLE 60S...AND THE ENERGY FOR THIS AFTERNOONS STORMS. THE OVERNIGHT CONVECTION HAS NOW PASSED OFF TO THE EAST...AND WITH IT THE FLASH FLOOD THREAT. EVALUATING THE 04.00Z MODEL GUIDANCE...THE TREND IS SLOWER WITH THE NORTHEAST PROGRESSION OF THE OCCLUDED/COLD FRONT. THIS ALLOWS MORE OF THE FORECAST AREA IN WI TO BE PRE-FRONTAL AND IN THE WARM SECTOR FOR A HIGHER PROBABILITY OF SEVERE WEATHER. AS THE DAY PROGRESSES...QVECTOR CONVERGENCE WILL INCREASE AS A SHORTWAVE TROUGH IN COLORADO ROTATES AROUND THE LARGER SD TROUGH AND BEGINS ITS EASTWARD PROGRESSION. AS THE FORCING BEGINS TO INCREASE...NEAR/POST FRONTAL SHOWERS WILL LIKELY DEVELOP MUCH LIKE SEEN ON RADAR ALONG I-35 EARLY THIS MORNING. ALSO...BETTER UPPER LEVEL FORCING WILL BEGIN TO WORK TOWARD THE WARM SECTOR AND WORK WITH 0-2KM THETA-E CONVERGENCE ALONG THE FRONT. INSTABILITY IN THE WARM SECTOR WILL HIGHLY DEPEND ON THE EXTENT OF THE SHOWERS AND CLOUDS OVER WI...HOWEVER BECAUSE THE DEWPOINTS ARE ALREADY MIDDLE 60S...AT LEAST MARGINAL INSTABILITY WILL BE PRESENT BY 18Z. MUCAPES AROUND 1000-1500 J/KG LOOK TO BE A GOOD ESTIMATE ON AFTERNOON CAPE...POSSIBLY HIGHER WITH MORE CLOUD BREAKS. WIND SHEAR LOOKS TO INCREASE TODAY BUT RIGHT ON THE COLD/OCCLUDED FRONTAL BOUNDARY...TO MAKE IT A MARGINAL SUPERCELL DAY WITH MULTICELLS ALSO PRESENT. THE 05.06Z NAM AND 05.07Z RAP BOTH SUGGEST NEAR 40 KTS OF 0-6KM SHEAR...CERTAINLY ENOUGH FOR SUPERCELLS. THE 05.07Z RAP MIXES ALL THE PRE-FRONTAL SURFACE WINDS TO SOUTHERLY. THE 05.06Z NAM AND LATEST HRRR RUNS ARE VERY AGREEABLE THAT THE WARM FRONT WILL SHIFT NORTH TO ABOUT BLACK RIVER FALLS WI TODAY...VERY CLOSE TO THE SPC DAY 1 NORTHERN EXTENT OF THE SLIGHT RISK. EASTERLY FLOW IS FOUND NORTH OF THE WARM FRONT...WHICH EXTENDS TO THE EAST TOWARD KGRB...SO A GOOD CONVERGENT BOUNDARY. WHILE TORNADO PROBABILITIES DONT LOOK HIGH...THE TRIPLE POINT AREA AND ALONG THAT WARM FRONT THIS AFTERNOON WILL BE A FOCAL POINT. OTHERWISE...DAMAGING WIND SEGMENTS OR LARGE HAIL ARE THE MAIN THREATS FROM THE STORMS IN WI. NORTH OF THE WARM FRONT...LOW-LEVEL INVERTED CONDITIONS AND ELEVATED STORMS ARE FAVORED...HEAVY RAIN IS THE MAIN THREAT...WITH AN ISOLATED HAIL STORM POSSIBLE. THE FRONT SHOULD SHIFT EAST OF THE FORECAST AREA BY EARLY EVENING WITH STRONG DEWPOINT DECREASES. THUS...THE MAIN SEVERE WEATHER THREAT LOOKS TO BE ABOUT 1 PM TO 5 PM. BY TONIGHT...THE NE AND EASTERNMOST FORECAST AREA MAY STILL HAVE SOME RAIN REMAINING. HAVE SLOWED THAT SLIGHTLY FROM THE PREVIOUS FORECAST. A DECREASING TREND OCCURS THROUGH THE EVENING AS WEATHER SHIFTS EAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 413 AM CDT SAT OCT 5 2013 THE LATEST MODEL CONSENSUS IS TO NOW KEEP THE DEFORMATION ASSOCIATED WITH THE CYCLONIC MOIST FLOW WRAPPING AROUND THE LOW TO THE WEST-NORTHWEST ON SATURDAY. THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE LOW WHICH IS A BIT FURTHER SOUTH IN THE LATEST GUIDANCE. IN ANY CASE...CHANGES WERE MADE TO SUNDAY TO TRY AND DRY IT OUT WITH THE RAIN SHOWERS JUST WEST OF THE AREA. ALTHOUGH THE CONSENSUS OF THE MODELS IS TO BRING THAT BAND INTO THE FORECAST AREA FOR MONDAY NOW...THE LATEST 05.00Z ECMWF IS MUCH MORE PROGRESSIVE AND RAPIDLY SHIFTS THE SHOWERS EAST. HAVE A SMALL CHANCE OF SHOWERS TO ADDRESS THAT SITUATION. THE REMAINDER OF THE PERIOD IS DOMINATED BY DRY WEATHER UNDER && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 1140 PM CDT FRI OCT 4 2013 BACK EDGE OF THE CONVECTION IS MAKING STEADY EASTWARD PROGRESS AND STILL EXPECT IT TO CLEAR BOTH TAF SITES BY 08Z. UNTIL IT DOES...IFR CONDITIONS WILL REMAIN POSSIBLE AS LOCALLY HEAVY RAIN COULD DROP THE VISIBILITY AND POSSIBLY THE CEILINGS DOWN. ONCE THE RAIN MOVES THROUGH...A TEMPORARY DRY SLOT WILL MOVE INTO TO ALLOW FOR A PERIOD OF PRIMARILY VFR CONDITIONS. AS THE MAIN SURFACE LOW STARTS TO TRACK TOWARD THE AREA SATURDAY MORNING...EXPECT TO SEE THE OCCLUDED FRONT LIFT INTO AND THROUGH THE AREA. THE 05.00Z NAM SUGGESTS THAT AS THIS HAPPENS...THE LOW LEVEL MOISTURE TRANSPORT WILL INCREASE WITH THE NOSE OF THIS INTO THE AREA LONG THE OCCLUDED FRONT. THE MAIN UPPER LEVEL SYSTEM WILL ALSO BE APPROACHING TO PROVIDE ADDITIONAL FORCING AND EXPECTING TO SEE ANOTHER AREA OF SHOWERS AND SOME THUNDERSTORMS DEVELOP BY MID MORNING AND CONTINUE INTO THE EARLY AFTERNOON. CONSIDERABLE UNCERTAINTY ON WHAT THE CEILINGS WILL DO WITH THE OCCLUDED FRONT BUT MOST GUIDANCE SUGGEST A RETURN TO MVFR BEFORE DRIER STARTS TO SPREAD IN FROM THE WEST TO ALLOW THE RAIN TO END AND VFR CONDITIONS TO RETURN. && .HYDROLOGY... ISSUED AT 413 AM CDT SAT OCT 5 2013 CONCERNING THE FLASH FLOOD WATCH...WITH CURRENT CONVECTION EAST OF THE AREA...MAIN THREAT HAS DIMINISHED. AS AFTERNOON CONVECTION INCREASES...IT SHOULD BE AFFECTING AREAS THAT HAVE HAD LESS RAIN OVERALL THAN THOSE WEST OF THE MISS RIVER. AREAS EAST OF THE MISS RIVER CAN TAKE ANOTHER 1-2 INCHES...ESPECIALLY SWRN WI. THERE IS A SMALL PROBABILITY OF LOCALIZED FLASH FLOODING TODAY IN THE CENTRAL WI CORRIDOR IN THE PRE-FRONTAL AIR MASS WHICH WILL STILL HAVE 1.25 TO 1.75 INCH PRECIPITABLE WATER VALUES. RAIN RATES ARE EXPECTED TO BE HIGH...PROBABLY 2 TO 3 INCH PER HOUR SHOULD CAPE DEVELOP AS FORECAST. THE SLOW MOVEMENT OF THE FRONT DOES GIVE SOME CONCERN FOR FLOODING SO WILL ISSUE ANOTHER HYDROLOGICAL DISCUSSION FOR THAT AREA AND CANCEL THE FLASH FLOOD WATCH. THERE ARE SOME RIVER RESPONSES CURRENTLY OCCURRING. MONITORING THE ROOT RIVER BASIN AND THE UPPER IOWA RIVERS BOTH HAVE RESPONSES. ALSO THE WHITEWATER RIVER MIDDLE FORK THAT RUNS THROUGH WHITEWATER STATE PARK IS RISING. AT THIS TIME THESE WILL APPROACH FLOOD STAGE BUT IT IS BELIEVED THEY WILL NOT REACH IT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ UPDATE...BAUMGARDT SHORT TERM...BAUMGARDT LONG TERM...BAUMGARDT AVIATION...04
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
519 PM CDT SAT OCT 5 2013 .UPDATE... 453 PM CDT ONE CLUSTER OF SEVERE STORMS CONTINUES TO MOVE ACROSS NORTHERN COOK COUNTY AND OUT OVER LAKE MICHIGAN AT 450 PM CDT WITH WEAKER THOUGH STILL INTENSE STORMS SOUTHWARD INTO KANKAKEE COUNTY. SURFACE OBS SHOW AN AREA OF LOW LEVEL CONVERGENCE WHICH HAS DEVELOPED FROM EASTERN WILL OR CENTRAL KANKAKEE COUNTY SOUTHWESTWARD TOWARD BLOOMINGTON AND LINCOLN. ANOTHER SHORTWAVE IS MOVING NORTHEAST ACROSS WESTERN IL WITH AN AREA OF RAIN SHOWERS CLOSELY TIED TO IT APPROACHING LACON...PEORIA AND SPRINGFIELD. RADAR MOSAIC ALSO SHOWS SOME SPOTTY ECHOES DEVELOPING ALONG THE AFOREMENTIONED CONVERGENCE/TROUGH...LIKELY BEING AIDED BY THE APPROACHING WAVE. EXPECT THAT DEVELOPMENT WILL CONTINUE ALONG THE TROUGH FROM GARY TO KANKAKEE TO PONTIAC AND MOVE EAST-NORTHEAST OVER THE NEXT FEW HOURS. RAIN COOLED AIR IS TO THE SOUTH AND EAST OF THIS AREA WITH TEMPS IN THE 60S BUT MUCH OF THE SOUTHEAST CWA ITSELF HAS REMAINED NORTH OF THE RAIN ACTIVITY SO INSTABILITY IS STILL SUFFICIENT. LATEST RAP ANALYSIS SHOWS THE EFFECTIVE SHEAR HAS INCREASED INTO THE 40 KT RANGE. THEREFORE THE SEVERE THREAT WILL CONTINUE AND LIKELY BE FOCUSED ALONG AND EAST OF THE GARY TO KANKAKEE TO PONTIAC LINE WITH A SHORTER TERM THREAT ALSO CONTINUING ACROSS EASTERN LAKE COUNTY IL AND ADJACENT LAKE MICHIGAN WATERS AS EXISTING STORM CLUSTER MOVES OFFSHORE. HEAVY RAINFALL WILL CONTINUE WITH ANY STORMS WITH REPORTS OF 1 TO 1.5 INCHES OF RAIN IN LESS THAN AN HOURS TIME. COVERAGE MAY STILL BE FAIRLY LOCALIZED...ESPECIALLY WITH THE FAIRLY NARROW LINEAR STRUCTURE OF NEWLY DEVELOPING STORMS. AREAS TO THE NORTH AND WEST OF THE AREAS OUTLINED ABOVE WILL LIKELY SEE ANOTHER BAND OF LIGHTER RAINFALL AND POSSIBLY SOME EMBEDDED THUNDER ARRIVE FOR THE EARLY EVENING BASED ON THE MOVEMENT OF CURRENT ACTIVITY TOWARDS PEORIA AND SPRINGFIELD. THE ADDITIONAL SHORTWAVES NOTED IN THE EARLY AFTERNOON DISCUSSION BELOW WILL ALSO BRING ADDITIONAL CHANCES FOR ADDITIONAL SHOWERS AND POSSIBLY A FEW STORMS INTO THE OVERNIGHT...WITH THE WESTERN EDGE OF THE COVERAGE GRADUALLY SHIFTING EAST WITH EACH WAVE. THE THUNDER THREAT WILL DIMINISH OVERALL THROUGH THE EVENING AND END ACROSS THE WESTERN CWA INTO THE OVERNIGHT. MDB //PREV DISCUSSION... 215 PM CDT LATE AFTERNOON AND EARLY EVENING...STORMS AND ASSOCIATED SEVERE POTENTIAL ARE THE INITIAL FOCUS WITH SHRA/TSRA COVERAGE OVERNIGHT THE SECOND FOCUS. SURFACE LOW PRESSURE REMAINS CENTERED OVER FAR EASTERN SOUTH DAKOTA WITH AN OCCLUDED FRONT ARCHING EAST THEN SOUTHEAST TO A VERY WEAK LOW CIRCULATION NORTHEAST OF DECORAH IOWA. A COLD FRONT THEN EXTENDS SOUTHWARD ACROSS THE QUAD CITIES BACK INTO CENTRAL MISSOURI AS NOTED BY THE SHARP DROP OFF IN DEWPOINTS. THERE IS ANOTHER TROUGH AHEAD OF THE FRONT WHICH MAY BE THE REMNANTS OF EARLIER OUTFLOW THAT MOVED ACROSS EASTERN MISSOURI. WATER VAPOR SHOWS SEVERAL UPPER SHORTWAVES MOVING NORTHEASTWARD AROUND THE EASTERN FLANK OF A BIG CLOSED UPPER LOW CENTERED OVER SOUTHEAST SOUTH DAKOTA. THE TRACK OF THESE WAVES WILL BE RIGHT ACROSS THE LOCAL AREA THROUGH TONIGHT. THE FIRST WAVE IS MOVING INTO EASTERN IOWA WITH ANOTHER WAVE OVER WEST CENTRAL MISSOURI. A THIRD WAVE IS MOVING ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. ADDITIONAL WAVES HAVE ALSO BEEN ROLLING NORTHEAST ACROSS THE LOWER OHIO VALLEY AND CENTRAL IL/IN. ALL OF THIS MAKES FOR A RATHER MESSY PRECIP SITUATION. CURRENT RADAR MOSAIC SHOWS SEVERAL CLUSTERS OF BETTER ORGANIZED CONVECTION MAINLY AFFECTING THE NORTHERN AND SOUTHEASTERN EXTENTS OF THE CWA TIED TO VARIOUS SHORTWAVES TRAVERSING THE UPPER FLOW. ADDITIONAL SPOTTY SHOWERS CONTINUE TO POP ACROSS THE CHICAGO METRO AREA WHERE STRATUS HAS BEEN ERODING AND INSTABILITY GROWING. THE NEXT WAVE COMING FROM EASTERN IOWA SEEMS TO BE DRIVING ANOTHER CLUSTER OF WEAKER BUT SLOWLY INTENSIFYING CONVECTION NEAR STERLING AND PERU. THE IMMEDIATE CONCERN IS THE MORE INTENSE STORMS MOVING INTO THE SOUTHEASTERN CWA AND THE WEAKER CLUSTER NEAR PERU/STERLING WHICH MAY INTENSIFY AS IT MOVES INTO THE CWA. WITH LOWEST CLOUDS ERODING SIGNALING EROSION OF EARLIER CAP ALONG WITH WARMING ATMOSPHERE IS BETTER PRIMED WITH MIXED LAYER CAPES AROUND 1500 J/KG. EFFECTIVE SHEAR HAS BEEN ABLE TO INTENSIFY BASED ON LATEST RAP ANALYSIS WITH AROUND 40 KT EXPECTED. STORMS THAT HAVE AFFECTED THE AREA THUS FAR HAVE EXHIBITED LOW AND MID LEVEL ROTATION THOUGH IT HAS BEEN WEAK. IT DOES APPEAR THAT COVERAGE WILL BEGIN TO EXPAND OUTSIDE AREAS THAT ARE CURRENTLY SEEING STORMS SO WILL CONTINUE TO MONITOR FOR SEVERE GIVEN THE SUPPORTIVE ATMOSPHERE. COVERAGE IS THE MAIN QUESTION HOWEVER...WITH OVERALL SEVERE THREAT STILL SEEMING ISOLATED-SCATTERED. THREATS REMAIN LARGE HAIL AND DAMAGING WIND GUSTS...WITH ISOLATED TORNADOES STILL POSSIBLE BUT AT THIS POINT WITH NORTHERN AREAS STILL FAVORED WITH LOCALLY BACKED FLOW A BETTER POSSIBILITY GIVEN THE WEAK LOW CIRCULATION JUST TO THE NORTHWEST...BUT HAVE SEEN SEVERAL SITES ACROSS THE CENTRAL AND EASTERN CWA BACK SLIGHTLY. VERY HIGH LOW LEVEL CAPE IS IN PLACE ACROSS MUCH OF THE AREA SO CANNOT DISCOUNT THE TORNADO THREAT ELSEWHERE. WITH PRECIPITABLE WATER VALUES OF 1.5-1.7+ INCHES HEAVY RAINFALL IS A CONCERN WITH ANY STRONGER STORMS. WITH RECENT DRY WEATHER AND UNCERTAINTY IN THE COVERAGE OF THE MOST INTENSE STORMS VS. LESS INTENSE BROADER RAIN/EMBEDDED THUNDER WILL HOLD OFF ON A FLASH FLOOD WATCH FOR NOW BUT CONTINUE TO MONITOR. TONIGHT...DURATION OF SEVERE POTENTIAL IS THE NEXT QUESTION. WITH THE FRONT VERY SLOWLY MOVING EASTWARD THE MOIST AIRMASS WILL REMAIN IN PLACE BUT SUNSET WILL LIKELY ALLOW INSTABILITY TO WANE SO SEVERE THREAT SHOULD BE DIMINISHING THROUGH THE EVENING. POPS HOWEVER LOOK TO REMAIN RATHER HIGH AS THE NEXT SEVERAL SHORTWAVES MOVE ACROSS. THUS EXPECT THAT THERE WILL BE A FEW MORE ROUNDS OF SHOWERS AND STORMS TO AFFECT THE AREA...WITH THE THUNDER THREAT DIMINISHING ACROSS THE WESTERN CWA AS THE FRONT APPROACHES. WILL NEED TO HANG ONTO POPS THROUGH MUCH OF THE NIGHT ACROSS THE EASTERN HALF OR SO OF THE CWA...NAMELY BECAUSE THE OK/AR WAVE IS EXPECTED TO ARRIVE AFTER MIDNIGHT BRINGING MORE SHRA/TSRA WITH IT. ULTIMATELY...POPS WILL DECREASE FROM WEST TO EAST OVERNIGHT...WITH A QUICKER EASTWARD PROGRESSION TOWARD DAYBREAK. DRIER AIR WILL BEGIN TO WORK INTO THE WEST WITH DEWPOINTS FALLING INTO THE 40S WEST AND 50S EAST OVERNIGHT. MDB SUNDAY THROUGH NEXT SATURDAY... LINGERING UPPER LEVEL CUT OFF LOW AND ASSOCIATED INSTABILITY SHOWERS INITIALLY WILL BE REPLACED BY HIGH PRESSURE AND A GRADUAL WARMING TREND LATER IN THE WEEK LASTING INTO SATURDAY. UPPER LOW TO TRUDGE ACROSS NORTHERN IL LATER SUNDAY AND SUNDAY NIGHT.. AND INTO NW INDIANA MONDAY MORNING. MODELS APPEAR TO CONTINUE TO STRUGGLE WITH THIS PROGRESSION WITH BOTH MODEL TO MODEL AND RUN TO RUN INCONSISTENCIES. 12Z GFS SEEMS SOMEWHAT A MIDDLE GROUND BETWEEN THE SLOWER NAM/CANADIAN AND FASTER ECMWF AND WILL TREND IN THIS DIRECTION WITH DETERMINISTIC FORECAST/GRIDS. THE MOST SIGNIFICANT WEATHER ELEMENT HAVING BEARING ON THE DEPARTURE SPEED OF THE UPPER LOW IS LIKELY THE DURATION OF THE CHANCE OF INSTABILITY SHOWERS ASSOCIATED WITH THE THERMAL TROUGH AND STEEPER LAPSE RATES WITH AND IN THE WAKE OF THE LOW. MIDDLE GROUND APPROACH WOULD HAVE INSTABILITY SHOWERS ENDING BY ABOUT DUSK MONDAY...BUT SHOULD A SLOWER SOLUTION LIKE THE NAM/CANADIAN VERIFY...WE COULD SEE ISOLATED SHOWERS LINGERING INTO TUESDAY. EVENING AND OVERNIGHT FORECAST SHIFTS WILL MONITOR AND ADJUST ACCORDINGLY. INITIAL RESIDUAL MOISTURE/LOW CLOUDS AND WIDELY SCT SHOWERS IN THE WAKE OF THE FRONT WILL EXIT EASTERN ILLINOIS AND NW INDIANA SUNDAY MORNING AS DRY SLOT PUNCHES INTO THE AREA FROM THE SW. GIVEN DRYING SW SFC FLOW EXPECT VARIABLE CONDITIONS SUNDAY WITH A FAIR AMOUNT OF SUNSHINE FOR A PERIOD AT MOST LOCATIONS AND DESPITE PASSAGE OF A COLD FRONT MAX TEMPS WILL STILL BE NEAR TO ONLY A FEW DEGREES BELOW SEASONAL NORMS. DEPENDING ON AFOREMENTIONED TIMING OF UPPER LOW... MAY SEE WIDELY SCATTERED INSTABILITY SHOWERS DEVELOP WEST OF I-39 LATE IN THE DAY. UPPER LEVEL THERMAL TROUGH TRAVERSES THE AREA EARLY MONDAY. GIVEN THE PRESENCE OF LIMITED MOISTURE... AND THIS OUT OF PHASE TIMING OF THE UPPER THERMAL TROUGH WITH THE MIN/MAX DIURNAL HEATING OF THE DAY... FEEL COVERAGE OF INSTABILITY SHOWERS ON MONDAY WILL BE SOMEWHAT LIMITED AND WILL CONTINUE TO PLAY LOW POPS FOR THAT EVENT. INCREASED CLOUDINESS ON MONDAY WILL LIMIT MAX TEMPS TO LOWER 60S.. WITH PERHAPS A FEW AREAS STAYING IN THE UPPER 50S. UPPER LEVEL HEIGHTS RISE RATHER ABRUPTLY IN THE WAKE OF THE UPPER CUT OFF LOW TUESDAY AS A PROGRESSIVE UPPER LEVEL RIDGE BUILDS EAST ACROSS THE PLAINS AND INTO THE WESTERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. THIS ALLOWS FOR ABUNDANT SUNSHINE AND MILDER TEMPS TO RETURN TO THE AREA ON TUESDAY... AND BE THE START OF A GRADUAL WARMING TREND THAT WILL LAST THROUGH THE REST OF THE WEEK. SPRAWLING HIGH PRESSURE WILL HELP ENABLE MOSTLY SUNNY MILD DAYS AND MOSTLY CLEAR...COOL...AND CRISP NIGHTS MID TO LATE WEEK. WITH THE HIGH SLIDING TO JUST EAST OF THE AREA THURS-SAT...AN EXTENDED PERIOD OF WEAK SOUTHERLY FLOW WILL ALLOW FOR TEMPS TO RETURN TO ABOVE SEASONAL AVERAGES AND ANOTHER STRETCH OF DELIGHTFUL AUTUMN WEATHER. THE NEXT CHANCE OF RAIN WILL THEN COME LATE SATURDAY OR SUNDAY. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 22Z... * SSE WINDS SLOWLY BECOMING SOUTHWEST BY LATE THIS EVENING. * SCT -SHRA/-TSRA REMAINS POSSIBLE AROUND THE TERMINALS THROUGH 00Z...WITH MVFR CEILINGS IN THIS -TSRA. RODRIGUEZ //DISCUSSION...UPDATED 18Z... VERY MESSY FORECAST FOR THIS AFTERNOON. THE SURFACE LOW IS OVER SE SOUTH DAKOTA...ITS WARM FRONT IS OVER SOUTHERN WISCONSIN...AND ITS COLD FRONT IS OVER EASTERN IOWA. STRATUS IS STILL HOLDING STRONG ACROSS THE REGION...BUT LOOKING OUT THE WINDOW HERE...A FEW HOLES ARE BEGINNING TO FORM. EXPECTING CIGS TO LIFT TO HIGH END MVFR BY 19Z. WHILE THE LOW CIGS HAVE CAUSED HAVOC WITH BREAK AWAY POINTS...IT IS LIMITING OUR MIXING AND HAVE LOWERED WIND GUSTS TO 15KT. THERE IS A CHANCE WE MAY NOT SEE ANY WIND GUSTS AT ALL THIS AFTN. IN ADDITION...INSTABILITY IS MUCH LOWER THAN INITIALLY THOUGHT DUE TO THE STRATUS. THEREFORE MADE SOME CHANGES TO TS CHANCES THIS AFTN. FIRST AT RFD...THINKING THE TSRA PASSING OVER THE TERMINAL NOW WILL BE THE MAIN SHOW. EXPECTING JUST SHOWERS AFT 20Z...AND THEN DRY CONDITIONS AFT 22Z. FOR THE EASTERN TERMINALS...TIMING OF THE CURRENT AREA OF SCT TS HAS THEM ARRIVING AT 19Z. WIDER COVERAGE IS EXPECTED BTWN 20Z AND 23Z. SOME OF THE STORMS MAY PULSE UP AND BECOME STRONG TO SEVERE...BUT WIDESPREAD SEVERE WEATHER IS NO LONGER EXPECTED. THE SOUPY ENVIRONMENT OUTSIDE WILL RESULT IN REDUCED VSBYS IF ANY STRONG SHOWERS OR TSRA PASS OVERHEAD. OBSERVED VSBYS RANGE FROM 2.5SM TO 5SM SO KEPT 3SM GOING. ADDITIONAL SHOWERS ARE EXPECTED BEHIND THE TSRA FOR A FEW HOURS...THROUGH 03Z. WINDS WILL BECOME SW TONIGHT ARND 8KT. DESPITE THE DRIER AIR MOVING INTO THE REGION BEHIND THE COLD FRONT...KEPT MVFR CIGS IN THE TAFS AFT 00Z. ON SATELLITE THERE IS A REGION OF MVFR CIGS JUST ALONG AND BEHIND THE FRONT. GUIDANCE INDICATES THAT THE MOISTURE WILL LINGER BEHIND THE FRONT WITH MVFR CIGS HOLDING ON. WITH NO GOOD REASON TO PULL THE CIGS...DECIDED TO LEAVE THEM IN. EXPECTING THE LOWER CIGS TO BURN OFF SUNDAY MORNING WITH SW WINDS 10-15KT. THERE WILL BE A WINDOW OF SCT TO CLEAR SKIES ASSOCIATED WITH THE LOWS DRY SLOT MOVING OVER THE TERMINALS TOMORROW WITH ANOTHER ROUND OF MVFR-VFR CIGS BEHIND IT. JEE //ORD AND MDW CONFIDENCE...UPDATED 22Z... * MEDIUM HIGH CONFIDENCE WITH WIND SPEED/DIRECTION. * MEDIUM HIGH CONFIDENCE WITH -SHRA/-TSRA TRENDS. RODRIGUEZ //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PSBL MVFR CIGS AND CHC SHRA. MONDAY...MVFR CIGS/VSBYS WITH SHRA. PSBL POCKETS OF IFR CIGS. TUESDAY THROUGH FRIDAY...VFR. BEACHLER && .MARINE... 1228 PM CDT LOW PRESSURE WAS OVER EASTERN SOUTH DAKOTA THIS AFTERNOON WITH A WITH AN OCCLUDED FRONT INTO WISCONSIN AND A COLD FRONT EXTENDING SOUTH THROUGH ILLINOIS. THE COLD FRONT WILL MOVE THROUGH SOUTH AND CENTRAL LAKE MICHIGAN TONIGHT WITH PERIODS OF SHOWERS AND THUNDERSTORMS. THIS WILL TURN WINDS FROM SOUTH TO SOUTHWEST. STRONG EASTERLY FLOW WILL CONTINUE NORTH OF THE FRONT OVER NORTHERN LAKE MICHIGAN. THE FRONT WILL FINALLY REACH NORTHERN LAKE MICHIGAN SUNDAY AS THE LOW MOVES TO EASTERN LAKE SUPERIOR. THIS WILL ALLOW WINDS TO DIMINISH AND SHIFT SOUTH TO SOUTHWEST OVER THE NORTH END OF THE LAKE. THE LOW WILL CONTINUE TO LIFT NORTHEAST INTO EASTERN ONTARIO SUNDAY NIGHT AND MONDAY BUT A WEAK TROF OF LOW PRESSURE WILL REMAIN OVER LAKE MICHIGAN. AS THE TROF PASSES...WINDS WILL SHIFT TO NORTHWEST AND INCREASE MONDAY AFTERNOON. HIGH PRESSURE WILL GRADUALLY BUILD INTO THE WESTERN GREAT LAKES MONDAY NIGHT AND TUESDAY MORNING CAUSING WINDS TO BECOME LIGHT AND VARIABLE. SOUTHERLY FLOW WILL RETURN TO LAKE MICHIGAN FOR AN EXTENDED PERIOD FROM WEDNESDAY THROUGH THE END OF THE WEEK. ALLSOPP && .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
458 PM CDT SAT OCT 5 2013 .UPDATE... 453 PM CDT ONE CLUSTER OF SEVERE STORMS CONTINUES TO MOVE ACROSS NORTHERN COOK COUNTY AND OUT OVER LAKE MICHIGAN AT 450 PM CDT WITH WEAKER THOUGH STILL INTENSE STORMS SOUTHWARD INTO KANKAKEE COUNTY. SURFACE OBS SHOW AN AREA OF LOW LEVEL CONVERGENCE WHICH HAS DEVELOPED FROM EASTERN WILL OR CENTRAL KANKAKEE COUNTY SOUTHWESTWARD TOWARD BLOOMINGTON AND LINCOLN. ANOTHER SHORTWAVE IS MOVING NORTHEAST ACROSS WESTERN IL WITH AN AREA OF RAIN SHOWERS CLOSELY TIED TO IT APPROACHING LACON...PEORIA AND SPRINGFIELD. RADAR MOSAIC ALSO SHOWS SOME SPOTTY ECHOES DEVELOPING ALONG THE AFOREMENTIONED CONVERGENCE/TROUGH...LIKELY BEING AIDED BY THE APPROACHING WAVE. EXPECT THAT DEVELOPMENT WILL CONTINUE ALONG THE TROUGH FROM GARY TO KANKAKEE TO PONTIAC AND MOVE EAST-NORTHEAST OVER THE NEXT FEW HOURS. RAIN COOLED AIR IS TO THE SOUTH AND EAST OF THIS AREA WITH TEMPS IN THE 60S BUT MUCH OF THE SOUTHEAST CWA ITSELF HAS REMAINED NORTH OF THE RAIN ACTIVITY SO INSTABILITY IS STILL SUFFICIENT. LATEST RAP ANALYSIS SHOWS THE EFFECTIVE SHEAR HAS INCREASED INTO THE 40 KT RANGE. THEREFORE THE SEVERE THREAT WILL CONTINUE AND LIKELY BE FOCUSED ALONG AND EAST OF THE GARY TO KANKAKEE TO PONTIAC LINE WITH A SHORTER TERM THREAT ALSO CONTINUING ACROSS EASTERN LAKE COUNTY IL AND ADJACENT LAKE MICHIGAN WATERS AS EXISTING STORM CLUSTER MOVES OFFSHORE. HEAVY RAINFALL WILL CONTINUE WITH ANY STORMS WITH REPORTS OF 1 TO 1.5 INCHES OF RAIN IN LESS THAN AN HOURS TIME. COVERAGE MAY STILL BE FAIRLY LOCALIZED...ESPECIALLY WITH THE FAIRLY NARROW LINEAR STRUCTURE OF NEWLY DEVELOPING STORMS. AREAS TO THE NORTH AND WEST OF THE AREAS OUTLINED ABOVE WILL LIKELY SEE ANOTHER BAND OF LIGHTER RAINFALL AND POSSIBLY SOME EMBEDDED THUNDER ARRIVE FOR THE EARLY EVENING BASED ON THE MOVEMENT OF CURRENT ACTIVITY TOWARDS PEORIA AND SPRINGFIELD. THE ADDITIONAL SHORTWAVES NOTED IN THE EARLY AFTERNOON DISCUSSION BELOW WILL ALSO BRING ADDITIONAL CHANCES FOR ADDITIONAL SHOWERS AND POSSIBLY A FEW STORMS INTO THE OVERNIGHT...WITH THE WESTERN EDGE OF THE COVERAGE GRADUALLY SHIFTING EAST WITH EACH WAVE. THE THUNDER THREAT WILL DIMINISH OVERALL THROUGH THE EVENING AND END ACROSS THE WESTERN CWA INTO THE OVERNIGHT. MDB //PREV DISCUSSION... 215 PM CDT LATE AFTERNOON AND EARLY EVENING...STORMS AND ASSOCIATED SEVERE POTENTIAL ARE THE INITIAL FOCUS WITH SHRA/TSRA COVERAGE OVERNIGHT THE SECOND FOCUS. SURFACE LOW PRESSURE REMAINS CENTERED OVER FAR EASTERN SOUTH DAKOTA WITH AN OCCLUDED FRONT ARCHING EAST THEN SOUTHEAST TO A VERY WEAK LOW CIRCULATION NORTHEAST OF DECORAH IOWA. A COLD FRONT THEN EXTENDS SOUTHWARD ACROSS THE QUAD CITIES BACK INTO CENTRAL MISSOURI AS NOTED BY THE SHARP DROP OFF IN DEWPOINTS. THERE IS ANOTHER TROUGH AHEAD OF THE FRONT WHICH MAY BE THE REMNANTS OF EARLIER OUTFLOW THAT MOVED ACROSS EASTERN MISSOURI. WATER VAPOR SHOWS SEVERAL UPPER SHORTWAVES MOVING NORTHEASTWARD AROUND THE EASTERN FLANK OF A BIG CLOSED UPPER LOW CENTERED OVER SOUTHEAST SOUTH DAKOTA. THE TRACK OF THESE WAVES WILL BE RIGHT ACROSS THE LOCAL AREA THROUGH TONIGHT. THE FIRST WAVE IS MOVING INTO EASTERN IOWA WITH ANOTHER WAVE OVER WEST CENTRAL MISSOURI. A THIRD WAVE IS MOVING ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. ADDITIONAL WAVES HAVE ALSO BEEN ROLLING NORTHEAST ACROSS THE LOWER OHIO VALLEY AND CENTRAL IL/IN. ALL OF THIS MAKES FOR A RATHER MESSY PRECIP SITUATION. CURRENT RADAR MOSAIC SHOWS SEVERAL CLUSTERS OF BETTER ORGANIZED CONVECTION MAINLY AFFECTING THE NORTHERN AND SOUTHEASTERN EXTENTS OF THE CWA TIED TO VARIOUS SHORTWAVES TRAVERSING THE UPPER FLOW. ADDITIONAL SPOTTY SHOWERS CONTINUE TO POP ACROSS THE CHICAGO METRO AREA WHERE STRATUS HAS BEEN ERODING AND INSTABILITY GROWING. THE NEXT WAVE COMING FROM EASTERN IOWA SEEMS TO BE DRIVING ANOTHER CLUSTER OF WEAKER BUT SLOWLY INTENSIFYING CONVECTION NEAR STERLING AND PERU. THE IMMEDIATE CONCERN IS THE MORE INTENSE STORMS MOVING INTO THE SOUTHEASTERN CWA AND THE WEAKER CLUSTER NEAR PERU/STERLING WHICH MAY INTENSIFY AS IT MOVES INTO THE CWA. WITH LOWEST CLOUDS ERODING SIGNALING EROSION OF EARLIER CAP ALONG WITH WARMING ATMOSPHERE IS BETTER PRIMED WITH MIXED LAYER CAPES AROUND 1500 J/KG. EFFECTIVE SHEAR HAS BEEN ABLE TO INTENSIFY BASED ON LATEST RAP ANALYSIS WITH AROUND 40 KT EXPECTED. STORMS THAT HAVE AFFECTED THE AREA THUS FAR HAVE EXHIBITED LOW AND MID LEVEL ROTATION THOUGH IT HAS BEEN WEAK. IT DOES APPEAR THAT COVERAGE WILL BEGIN TO EXPAND OUTSIDE AREAS THAT ARE CURRENTLY SEEING STORMS SO WILL CONTINUE TO MONITOR FOR SEVERE GIVEN THE SUPPORTIVE ATMOSPHERE. COVERAGE IS THE MAIN QUESTION HOWEVER...WITH OVERALL SEVERE THREAT STILL SEEMING ISOLATED-SCATTERED. THREATS REMAIN LARGE HAIL AND DAMAGING WIND GUSTS...WITH ISOLATED TORNADOES STILL POSSIBLE BUT AT THIS POINT WITH NORTHERN AREAS STILL FAVORED WITH LOCALLY BACKED FLOW A BETTER POSSIBILITY GIVEN THE WEAK LOW CIRCULATION JUST TO THE NORTHWEST...BUT HAVE SEEN SEVERAL SITES ACROSS THE CENTRAL AND EASTERN CWA BACK SLIGHTLY. VERY HIGH LOW LEVEL CAPE IS IN PLACE ACROSS MUCH OF THE AREA SO CANNOT DISCOUNT THE TORNADO THREAT ELSEWHERE. WITH PRECIPITABLE WATER VALUES OF 1.5-1.7+ INCHES HEAVY RAINFALL IS A CONCERN WITH ANY STRONGER STORMS. WITH RECENT DRY WEATHER AND UNCERTAINTY IN THE COVERAGE OF THE MOST INTENSE STORMS VS. LESS INTENSE BROADER RAIN/EMBEDDED THUNDER WILL HOLD OFF ON A FLASH FLOOD WATCH FOR NOW BUT CONTINUE TO MONITOR. TONIGHT...DURATION OF SEVERE POTENTIAL IS THE NEXT QUESTION. WITH THE FRONT VERY SLOWLY MOVING EASTWARD THE MOIST AIRMASS WILL REMAIN IN PLACE BUT SUNSET WILL LIKELY ALLOW INSTABILITY TO WANE SO SEVERE THREAT SHOULD BE DIMINISHING THROUGH THE EVENING. POPS HOWEVER LOOK TO REMAIN RATHER HIGH AS THE NEXT SEVERAL SHORTWAVES MOVE ACROSS. THUS EXPECT THAT THERE WILL BE A FEW MORE ROUNDS OF SHOWERS AND STORMS TO AFFECT THE AREA...WITH THE THUNDER THREAT DIMINISHING ACROSS THE WESTERN CWA AS THE FRONT APPROACHES. WILL NEED TO HANG ONTO POPS THROUGH MUCH OF THE NIGHT ACROSS THE EASTERN HALF OR SO OF THE CWA...NAMELY BECAUSE THE OK/AR WAVE IS EXPECTED TO ARRIVE AFTER MIDNIGHT BRINGING MORE SHRA/TSRA WITH IT. ULTIMATELY...POPS WILL DECREASE FROM WEST TO EAST OVERNIGHT...WITH A QUICKER EASTWARD PROGRESSION TOWARD DAYBREAK. DRIER AIR WILL BEGIN TO WORK INTO THE WEST WITH DEWPOINTS FALLING INTO THE 40S WEST AND 50S EAST OVERNIGHT. MDB SUNDAY THROUGH NEXT SATURDAY... LINGERING UPPER LEVEL CUT OFF LOW AND ASSOCIATED INSTABILITY SHOWERS INITIALLY WILL BE REPLACED BY HIGH PRESSURE AND A GRADUAL WARMING TREND LATER IN THE WEEK LASTING INTO SATURDAY. UPPER LOW TO TRUDGE ACROSS NORTHERN IL LATER SUNDAY AND SUNDAY NIGHT.. AND INTO NW INDIANA MONDAY MORNING. MODELS APPEAR TO CONTINUE TO STRUGGLE WITH THIS PROGRESSION WITH BOTH MODEL TO MODEL AND RUN TO RUN INCONSISTENCIES. 12Z GFS SEEMS SOMEWHAT A MIDDLE GROUND BETWEEN THE SLOWER NAM/CANADIAN AND FASTER ECMWF AND WILL TREND IN THIS DIRECTION WITH DETERMINISTIC FORECAST/GRIDS. THE MOST SIGNIFICANT WEATHER ELEMENT HAVING BEARING ON THE DEPARTURE SPEED OF THE UPPER LOW IS LIKELY THE DURATION OF THE CHANCE OF INSTABILITY SHOWERS ASSOCIATED WITH THE THERMAL TROUGH AND STEEPER LAPSE RATES WITH AND IN THE WAKE OF THE LOW. MIDDLE GROUND APPROACH WOULD HAVE INSTABILITY SHOWERS ENDING BY ABOUT DUSK MONDAY...BUT SHOULD A SLOWER SOLUTION LIKE THE NAM/CANADIAN VERIFY...WE COULD SEE ISOLATED SHOWERS LINGERING INTO TUESDAY. EVENING AND OVERNIGHT FORECAST SHIFTS WILL MONITOR AND ADJUST ACCORDINGLY. INITIAL RESIDUAL MOISTURE/LOW CLOUDS AND WIDELY SCT SHOWERS IN THE WAKE OF THE FRONT WILL EXIT EASTERN ILLINOIS AND NW INDIANA SUNDAY MORNING AS DRY SLOT PUNCHES INTO THE AREA FROM THE SW. GIVEN DRYING SW SFC FLOW EXPECT VARIABLE CONDITIONS SUNDAY WITH A FAIR AMOUNT OF SUNSHINE FOR A PERIOD AT MOST LOCATIONS AND DESPITE PASSAGE OF A COLD FRONT MAX TEMPS WILL STILL BE NEAR TO ONLY A FEW DEGREES BELOW SEASONAL NORMS. DEPENDING ON AFOREMENTIONED TIMING OF UPPER LOW... MAY SEE WIDELY SCATTERED INSTABILITY SHOWERS DEVELOP WEST OF I-39 LATE IN THE DAY. UPPER LEVEL THERMAL TROUGH TRAVERSES THE AREA EARLY MONDAY. GIVEN THE PRESENCE OF LIMITED MOISTURE... AND THIS OUT OF PHASE TIMING OF THE UPPER THERMAL TROUGH WITH THE MIN/MAX DIURNAL HEATING OF THE DAY... FEEL COVERAGE OF INSTABILITY SHOWERS ON MONDAY WILL BE SOMEWHAT LIMITED AND WILL CONTINUE TO PLAY LOW POPS FOR THAT EVENT. INCREASED CLOUDINESS ON MONDAY WILL LIMIT MAX TEMPS TO LOWER 60S.. WITH PERHAPS A FEW AREAS STAYING IN THE UPPER 50S. UPPER LEVEL HEIGHTS RISE RATHER ABRUPTLY IN THE WAKE OF THE UPPER CUT OFF LOW TUESDAY AS A PROGRESSIVE UPPER LEVEL RIDGE BUILDS EAST ACROSS THE PLAINS AND INTO THE WESTERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. THIS ALLOWS FOR ABUNDANT SUNSHINE AND MILDER TEMPS TO RETURN TO THE AREA ON TUESDAY... AND BE THE START OF A GRADUAL WARMING TREND THAT WILL LAST THROUGH THE REST OF THE WEEK. SPRAWLING HIGH PRESSURE WILL HELP ENABLE MOSTLY SUNNY MILD DAYS AND MOSTLY CLEAR...COOL...AND CRISP NIGHTS MID TO LATE WEEK. WITH THE HIGH SLIDING TO JUST EAST OF THE AREA THURS-SAT...AN EXTENDED PERIOD OF WEAK SOUTHERLY FLOW WILL ALLOW FOR TEMPS TO RETURN TO ABOVE SEASONAL AVERAGES AND ANOTHER STRETCH OF DELIGHTFUL AUTUMN WEATHER. THE NEXT CHANCE OF RAIN WILL THEN COME LATE SATURDAY OR SUNDAY. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * SOUTH WINDS ARND 10 KT. GUSTS ARND 15KT THIS AFTN AT MDW. * SCATTERED THUNDERSTORMS EXPECTED THRU 23Z. SOME MAY BE STRONG TO SEVERE. * MODERATE RAIN THAT MAY CAUSE 6SM VSBY 00Z-03Z. * WINDS BECOME SW AFTER THE FRONT ALONG WITH MVFR CIGS IMPROVING TO VFR MID SUNDAY MORNING. JEE //DISCUSSION...UPDATED 18Z... VERY MESSY FORECAST FOR THIS AFTERNOON. THE SURFACE LOW IS OVER SE SOUTH DAKOTA...ITS WARM FRONT IS OVER SOUTHERN WISCONSIN...AND ITS COLD FRONT IS OVER EASTERN IOWA. STRATUS IS STILL HOLDING STRONG ACROSS THE REGION...BUT LOOKING OUT THE WINDOW HERE...A FEW HOLES ARE BEGINNING TO FORM. EXPECTING CIGS TO LIFT TO HIGH END MVFR BY 19Z. WHILE THE LOW CIGS HAVE CAUSED HAVOC WITH BREAK AWAY POINTS...IT IS LIMITING OUR MIXING AND HAVE LOWERED WIND GUSTS TO 15KT. THERE IS A CHANCE WE MAY NOT SEE ANY WIND GUSTS AT ALL THIS AFTN. IN ADDITION...INSTABILITY IS MUCH LOWER THAN INITIALLY THOUGHT DUE TO THE STRATUS. THEREFORE MADE SOME CHANGES TO TS CHANCES THIS AFTN. FIRST AT RFD...THINKING THE TSRA PASSING OVER THE TERMINAL NOW WILL BE THE MAIN SHOW. EXPECTING JUST SHOWERS AFT 20Z...AND THEN DRY CONDITIONS AFT 22Z. FOR THE EASTERN TERMINALS...TIMING OF THE CURRENT AREA OF SCT TS HAS THEM ARRIVING AT 19Z. WIDER COVERAGE IS EXPECTED BTWN 20Z AND 23Z. SOME OF THE STORMS MAY PULSE UP AND BECOME STRONG TO SEVERE...BUT WIDESPREAD SEVERE WEATHER IS NO LONGER EXPECTED. THE SOUPY ENVIRONMENT OUTSIDE WILL RESULT IN REDUCED VSBYS IF ANY STRONG SHOWERS OR TSRA PASS OVERHEAD. OBSERVED VSBYS RANGE FROM 2.5SM TO 5SM SO KEPT 3SM GOING. ADDITIONAL SHOWERS ARE EXPECTED BEHIND THE TSRA FOR A FEW HOURS...THROUGH 03Z. WINDS WILL BECOME SW TONIGHT ARND 8KT. DESPITE THE DRIER AIR MOVING INTO THE REGION BEHIND THE COLD FRONT...KEPT MVFR CIGS IN THE TAFS AFT 00Z. ON SATELLITE THERE IS A REGION OF MVFR CIGS JUST ALONG AND BEHIND THE FRONT. GUIDANCE INDICATES THAT THE MOISTURE WILL LINGER BEHIND THE FRONT WITH MVFR CIGS HOLDING ON. WITH NO GOOD REASON TO PULL THE CIGS...DECIDED TO LEAVE THEM IN. EXPECTING THE LOWER CIGS TO BURN OFF SUNDAY MORNING WITH SW WINDS 10-15KT. THERE WILL BE A WINDOW OF SCT TO CLEAR SKIES ASSOCIATED WITH THE LOWS DRY SLOT MOVING OVER THE TERMINALS TOMORROW WITH ANOTHER ROUND OF MVFR-VFR CIGS BEHIND IT. JEE //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN THUNDERSTORM FORECAST. * MEDIUM-LOW CONFIDENCE IN CIG HEIGHTS THIS EVENING AND OVERNIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PSBL MVFR CIGS AND CHC SHRA. MONDAY...MVFR CIGS/VSBYS WITH SHRA. PSBL POCKETS OF IFR CIGS. TUESDAY THROUGH FRIDAY...VFR. BEACHLER && .MARINE... 1228 PM CDT LOW PRESSURE WAS OVER EASTERN SOUTH DAKOTA THIS AFTERNOON WITH A WITH AN OCCLUDED FRONT INTO WISCONSIN AND A COLD FRONT EXTENDING SOUTH THROUGH ILLINOIS. THE COLD FRONT WILL MOVE THROUGH SOUTH AND CENTRAL LAKE MICHIGAN TONIGHT WITH PERIODS OF SHOWERS AND THUNDERSTORMS. THIS WILL TURN WINDS FROM SOUTH TO SOUTHWEST. STRONG EASTERLY FLOW WILL CONTINUE NORTH OF THE FRONT OVER NORTHERN LAKE MICHIGAN. THE FRONT WILL FINALLY REACH NORTHERN LAKE MICHIGAN SUNDAY AS THE LOW MOVES TO EASTERN LAKE SUPERIOR. THIS WILL ALLOW WINDS TO DIMINISH AND SHIFT SOUTH TO SOUTHWEST OVER THE NORTH END OF THE LAKE. THE LOW WILL CONTINUE TO LIFT NORTHEAST INTO EASTERN ONTARIO SUNDAY NIGHT AND MONDAY BUT A WEAK TROF OF LOW PRESSURE WILL REMAIN OVER LAKE MICHIGAN. AS THE TROF PASSES...WINDS WILL SHIFT TO NORTHWEST AND INCREASE MONDAY AFTERNOON. HIGH PRESSURE WILL GRADUALLY BUILD INTO THE WESTERN GREAT LAKES MONDAY NIGHT AND TUESDAY MORNING CAUSING WINDS TO BECOME LIGHT AND VARIABLE. SOUTHERLY FLOW WILL RETURN TO LAKE MICHIGAN FOR AN EXTENDED PERIOD FROM WEDNESDAY THROUGH THE END OF THE WEEK. ALLSOPP && .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
247 PM CDT SAT OCT 5 2013 .DISCUSSION... 215 PM CDT LATE AFTERNOON AND EARLY EVENING...STORMS AND ASSOCIATED SEVERE POTENTIAL ARE THE INITIAL FOCUS WITH SHRA/TSRA COVERAGE OVERNIGHT THE SECOND FOCUS. SURFACE LOW PRESSURE REMAINS CENTERED OVER FAR EASTERN SOUTH DAKOTA WITH AN OCCLUDED FRONT ARCHING EAST THEN SOUTHEAST TO A VERY WEAK LOW CIRCULATION NORTHEAST OF DECORAH IOWA. A COLD FRONT THEN EXTENDS SOUTHWARD ACROSS THE QUAD CITIES BACK INTO CENTRAL MISSOURI AS NOTED BY THE SHARP DROP OFF IN DEWPOINTS. THERE IS ANOTHER TROUGH AHEAD OF THE FRONT WHICH MAY BE THE REMNANTS OF EARLIER OUTFLOW THAT MOVED ACROSS EASTERN MISSOURI. WATER VAPOR SHOWS SEVERAL UPPER SHORTWAVES MOVING NORTHEASTWARD AROUND THE EASTERN FLANK OF A BIG CLOSED UPPER LOW CENTERED OVER SOUTHEAST SOUTH DAKOTA. THE TRACK OF THESE WAVES WILL BE RIGHT ACROSS THE LOCAL AREA THROUGH TONIGHT. THE FIRST WAVE IS MOVING INTO EASTERN IOWA WITH ANOTHER WAVE OVER WEST CENTRAL MISSOURI. A THIRD WAVE IS MOVING ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. ADDITIONAL WAVES HAVE ALSO BEEN ROLLING NORTHEAST ACROSS THE LOWER OHIO VALLEY AND CENTRAL IL/IN. ALL OF THIS MAKES FOR A RATHER MESSY PRECIP SITUATION. CURRENT RADAR MOSAIC SHOWS SEVERAL CLUSTERS OF BETTER ORGANIZED CONVECTION MAINLY AFFECTING THE NORTHERN AND SOUTHEASTERN EXTENTS OF THE CWA TIED TO VARIOUS SHORTWAVES TRAVERSING THE UPPER FLOW. ADDITIONAL SPOTTY SHOWERS CONTINUE TO POP ACROSS THE CHICAGO METRO AREA WHERE STRATUS HAS BEEN ERODING AND INSTABILITY GROWING. THE NEXT WAVE COMING FROM EASTERN IOWA SEEMS TO BE DRIVING ANOTHER CLUSTER OF WEAKER BUT SLOWLY INTENSIFYING CONVECTION NEAR STERLING AND PERU. THE IMMEDIATE CONCERN IS THE MORE INTENSE STORMS MOVING INTO THE SOUTHEASTERN CWA AND THE WEAKER CLUSTER NEAR PERU/STERLING WHICH MAY INTENSIFY AS IT MOVES INTO THE CWA. WITH LOWEST CLOUDS ERODING SIGNALING EROSION OF EARLIER CAP ALONG WITH WARMING ATMOSPHERE IS BETTER PRIMED WITH MIXED LAYER CAPES AROUND 1500 J/KG. EFFECTIVE SHEAR HAS BEEN ABLE TO INTENSIFY BASED ON LATEST RAP ANALYSIS WITH AROUND 40 KT EXPECTED. STORMS THAT HAVE AFFECTED THE AREA THUS FAR HAVE EXHIBITED LOW AND MID LEVEL ROTATION THOUGH IT HAS BEEN WEAK. IT DOES APPEAR THAT COVERAGE WILL BEGIN TO EXPAND OUTSIDE AREAS THAT ARE CURRENTLY SEEING STORMS SO WILL CONTINUE TO MONITOR FOR SEVERE GIVEN THE SUPPORTIVE ATMOSPHERE. COVERAGE IS THE MAIN QUESTION HOWEVER...WITH OVERALL SEVERE THREAT STILL SEEMING ISOLATED-SCATTERED. THREATS REMAIN LARGE HAIL AND DAMAGING WIND GUSTS...WITH ISOLATED TORNADOES STILL POSSIBLE BUT AT THIS POINT WITH NORTHERN AREAS STILL FAVORED WITH LOCALLY BACKED FLOW A BETTER POSSIBILITY GIVEN THE WEAK LOW CIRCULATION JUST TO THE NORTHWEST...BUT HAVE SEEN SEVERAL SITES ACROSS THE CENTRAL AND EASTERN CWA BACK SLIGHTLY. VERY HIGH LOW LEVEL CAPE IS IN PLACE ACROSS MUCH OF THE AREA SO CANNOT DISCOUNT THE TORNADO THREAT ELSEWHERE. WITH PRECIPITABLE WATER VALUES OF 1.5-1.7+ INCHES HEAVY RAINFALL IS A CONCERN WITH ANY STRONGER STORMS. WITH RECENT DRY WEATHER AND UNCERTAINTY IN THE COVERAGE OF THE MOST INTENSE STORMS VS. LESS INTENSE BROADER RAIN/EMBEDDED THUNDER WILL HOLD OFF ON A FLASH FLOOD WATCH FOR NOW BUT CONTINUE TO MONITOR. TONIGHT...DURATION OF SEVERE POTENTIAL IS THE NEXT QUESTION. WITH THE FRONT VERY SLOWLY MOVING EASTWARD THE MOIST AIRMASS WILL REMAIN IN PLACE BUT SUNSET WILL LIKELY ALLOW INSTABILITY TO WANE SO SEVERE THREAT SHOULD BE DIMINISHING THROUGH THE EVENING. POPS HOWEVER LOOK TO REMAIN RATHER HIGH AS THE NEXT SEVERAL SHORTWAVES MOVE ACROSS. THUS EXPECT THAT THERE WILL BE A FEW MORE ROUNDS OF SHOWERS AND STORMS TO AFFECT THE AREA...WITH THE THUNDER THREAT DIMINISHING ACROSS THE WESTERN CWA AS THE FRONT APPROACHES. WILL NEED TO HANG ONTO POPS THROUGH MUCH OF THE NIGHT ACROSS THE EASTERN HALF OR SO OF THE CWA...NAMELY BECAUSE THE OK/AR WAVE IS EXPECTED TO ARRIVE AFTER MIDNIGHT BRINGING MORE SHRA/TSRA WITH IT. ULTIMATELY...POPS WILL DECREASE FROM WEST TO EAST OVERNIGHT...WITH A QUICKER EASTWARD PROGRESSION TOWARD DAYBREAK. DRIER AIR WILL BEGIN TO WORK INTO THE WEST WITH DEWPOINTS FALLING INTO THE 40S WEST AND 50S EAST OVERNIGHT. MDB SUNDAY THROUGH NEXT SATURDAY... LINGERING UPPER LEVEL CUT OFF LOW AND ASSOCIATED INSTABILITY SHOWERS INITIALLY WILL BE REPLACED BY HIGH PRESSURE AND A GRADUAL WARMING TREND LATER IN THE WEEK LASTING INTO SATURDAY. UPPER LOW TO TRUDGE ACROSS NORTHERN IL LATER SUNDAY AND SUNDAY NIGHT.. AND INTO NW INDIANA MONDAY MORNING. MODELS APPEAR TO CONTINUE TO STRUGGLE WITH THIS PROGRESSION WITH BOTH MODEL TO MODEL AND RUN TO RUN INCONSISTENCIES. 12Z GFS SEEMS SOMEWHAT A MIDDLE GROUND BETWEEN THE SLOWER NAM/CANADIAN AND FASTER ECMWF AND WILL TREND IN THIS DIRECTION WITH DETERMINISTIC FORECAST/GRIDS. THE MOST SIGNIFICANT WEATHER ELEMENT HAVING BEARING ON THE DEPARTURE SPEED OF THE UPPER LOW IS LIKELY THE DURATION OF THE CHANCE OF INSTABILITY SHOWERS ASSOCIATED WITH THE THERMAL TROUGH AND STEEPER LAPSE RATES WITH AND IN THE WAKE OF THE LOW. MIDDLE GROUND APPROACH WOULD HAVE INSTABILITY SHOWERS ENDING BY ABOUT DUSK MONDAY...BUT SHOULD A SLOWER SOLUTION LIKE THE NAM/CANADIAN VERIFY...WE COULD SEE ISOLATED SHOWERS LINGERING INTO TUESDAY. EVENING AND OVERNIGHT FORECAST SHIFTS WILL MONITOR AND ADJUST ACCORDINGLY. INITIAL RESIDUAL MOISTURE/LOW CLOUDS AND WIDELY SCT SHOWERS IN THE WAKE OF THE FRONT WILL EXIT EASTERN ILLINOIS AND NW INDIANA SUNDAY MORNING AS DRY SLOT PUNCHES INTO THE AREA FROM THE SW. GIVEN DRYING SW SFC FLOW EXPECT VARIABLE CONDITIONS SUNDAY WITH A FAIR AMOUNT OF SUNSHINE FOR A PERIOD AT MOST LOCATIONS AND DESPITE PASSAGE OF A COLD FRONT MAX TEMPS WILL STILL BE NEAR TO ONLY A FEW DEGREES BELOW SEASONAL NORMS. DEPENDING ON AFOREMENTIONED TIMING OF UPPER LOW... MAY SEE WIDELY SCATTERED INSTABILITY SHOWERS DEVELOP WEST OF I-39 LATE IN THE DAY. UPPER LEVEL THERMAL TROUGH TRAVERSES THE AREA EARLY MONDAY. GIVEN THE PRESENCE OF LIMITED MOISTURE... AND THIS OUT OF PHASE TIMING OF THE UPPER THERMAL TROUGH WITH THE MIN/MAX DIURNAL HEATING OF THE DAY... FEEL COVERAGE OF INSTABILITY SHOWERS ON MONDAY WILL BE SOMEWHAT LIMITED AND WILL CONTINUE TO PLAY LOW POPS FOR THAT EVENT. INCREASED CLOUDINESS ON MONDAY WILL LIMIT MAX TEMPS TO LOWER 60S.. WITH PERHAPS A FEW AREAS STAYING IN THE UPPER 50S. UPPER LEVEL HEIGHTS RISE RATHER ABRUPTLY IN THE WAKE OF THE UPPER CUT OFF LOW TUESDAY AS A PROGRESSIVE UPPER LEVEL RIDGE BUILDS EAST ACROSS THE PLAINS AND INTO THE WESTERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. THIS ALLOWS FOR ABUNDANT SUNSHINE AND MILDER TEMPS TO RETURN TO THE AREA ON TUESDAY... AND BE THE START OF A GRADUAL WARMING TREND THAT WILL LAST THROUGH THE REST OF THE WEEK. SPRAWLING HIGH PRESSURE WILL HELP ENABLE MOSTLY SUNNY MILD DAYS AND MOSTLY CLEAR...COOL...AND CRISP NIGHTS MID TO LATE WEEK. WITH THE HIGH SLIDING TO JUST EAST OF THE AREA THURS-SAT...AN EXTENDED PERIOD OF WEAK SOUTHERLY FLOW WILL ALLOW FOR TEMPS TO RETURN TO ABOVE SEASONAL AVERAGES AND ANOTHER STRETCH OF DELIGHTFUL AUTUMN WEATHER. THE NEXT CHANCE OF RAIN WILL THEN COME LATE SATURDAY OR SUNDAY. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 20Z... * SOUTH WINDS ARND 10 KT. GUSTS ARND 15KT THIS AFTN AT MDW. * SCATTERED THUNDERSTORMS EXPECTED THRU 23Z. SOME MAY BE STRONG TO SEVERE. * MODERATE RAIN THAT MAY CAUSE 6SM VSBY 00Z-03Z. * WINDS BECOME SW AFTER THE FRONT ALONG WITH MVFR CIGS IMPROVING TO VFR MID SUNDAY MORNING. JEE //DISCUSSION...UPDATED 18Z... VERY MESSY FORECAST FOR THIS AFTERNOON. THE SURFACE LOW IS OVER SE SOUTH DAKOTA...ITS WARM FRONT IS OVER SOUTHERN WISCONSIN...AND ITS COLD FRONT IS OVER EASTERN IOWA. STRATUS IS STILL HOLDING STRONG ACROSS THE REGION...BUT LOOKING OUT THE WINDOW HERE...A FEW HOLES ARE BEGINNING TO FORM. EXPECTING CIGS TO LIFT TO HIGH END MVFR BY 19Z. WHILE THE LOW CIGS HAVE CAUSED HAVOC WITH BREAK AWAY POINTS...IT IS LIMITING OUR MIXING AND HAVE LOWERED WIND GUSTS TO 15KT. THERE IS A CHANCE WE MAY NOT SEE ANY WIND GUSTS AT ALL THIS AFTN. IN ADDITION...INSTABILITY IS MUCH LOWER THAN INITIALLY THOUGHT DUE TO THE STRATUS. THEREFORE MADE SOME CHANGES TO TS CHANCES THIS AFTN. FIRST AT RFD...THINKING THE TSRA PASSING OVER THE TERMINAL NOW WILL BE THE MAIN SHOW. EXPECTING JUST SHOWERS AFT 20Z...AND THEN DRY CONDITIONS AFT 22Z. FOR THE EASTERN TERMINALS...TIMING OF THE CURRENT AREA OF SCT TS HAS THEM ARRIVING AT 19Z. WIDER COVERAGE IS EXPECTED BTWN 20Z AND 23Z. SOME OF THE STORMS MAY PULSE UP AND BECOME STRONG TO SEVERE...BUT WIDESPREAD SEVERE WEATHER IS NO LONGER EXPECTED. THE SOUPY ENVIRONMENT OUTSIDE WILL RESULT IN REDUCED VSBYS IF ANY STRONG SHOWERS OR TSRA PASS OVERHEAD. OBSERVED VSBYS RANGE FROM 2.5SM TO 5SM SO KEPT 3SM GOING. ADDITIONAL SHOWERS ARE EXPECTED BEHIND THE TSRA FOR A FEW HOURS...THROUGH 03Z. WINDS WILL BECOME SW TONIGHT ARND 8KT. DESPITE THE DRIER AIR MOVING INTO THE REGION BEHIND THE COLD FRONT...KEPT MVFR CIGS IN THE TAFS AFT 00Z. ON SATELLITE THERE IS A REGION OF MVFR CIGS JUST ALONG AND BEHIND THE FRONT. GUIDANCE INDICATES THAT THE MOISTURE WILL LINGER BEHIND THE FRONT WITH MVFR CIGS HOLDING ON. WITH NO GOOD REASON TO PULL THE CIGS...DECIDED TO LEAVE THEM IN. EXPECTING THE LOWER CIGS TO BURN OFF SUNDAY MORNING WITH SW WINDS 10-15KT. THERE WILL BE A WINDOW OF SCT TO CLEAR SKIES ASSOCIATED WITH THE LOWS DRY SLOT MOVING OVER THE TERMINALS TOMORROW WITH ANOTHER ROUND OF MVFR-VFR CIGS BEHIND IT. JEE //ORD AND MDW CONFIDENCE...UPDATED 20Z... * HIGH CONFIDENCE IN THUNDERSTORM FORECAST. * MEDIUM-LOW CONFIDENCE IN CIG HEIGHTS THIS EVENING AND OVERNIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PSBL MVFR CIGS AND CHC SHRA. MONDAY...MVFR CIGS/VSBYS WITH SHRA. PSBL POCKETS OF IFR CIGS. TUESDAY THROUGH FRIDAY...VFR. BEACHLER && .MARINE... 1228 PM CDT LOW PRESSURE WAS OVER EASTERN SOUTH DAKOTA THIS AFTERNOON WITH A WITH AN OCCLUDED FRONT INTO WISCONSIN AND A COLD FRONT EXTENDING SOUTH THROUGH ILLINOIS. THE COLD FRONT WILL MOVE THROUGH SOUTH AND CENTRAL LAKE MICHIGAN TONIGHT WITH PERIODS OF SHOWERS AND THUNDERSTORMS. THIS WILL TURN WINDS FROM SOUTH TO SOUTHWEST. STRONG EASTERLY FLOW WILL CONTINUE NORTH OF THE FRONT OVER NORTHERN LAKE MICHIGAN. THE FRONT WILL FINALLY REACH NORTHERN LAKE MICHIGAN SUNDAY AS THE LOW MOVES TO EASTERN LAKE SUPERIOR. THIS WILL ALLOW WINDS TO DIMINISH AND SHIFT SOUTH TO SOUTHWEST OVER THE NORTH END OF THE LAKE. THE LOW WILL CONTINUE TO LIFT NORTHEAST INTO EASTERN ONTARIO SUNDAY NIGHT AND MONDAY BUT A WEAK TROF OF LOW PRESSURE WILL REMAIN OVER LAKE MICHIGAN. AS THE TROF PASSES...WINDS WILL SHIFT TO NORTHWEST AND INCREASE MONDAY AFTERNOON. HIGH PRESSURE WILL GRADUALLY BUILD INTO THE WESTERN GREAT LAKES MONDAY NIGHT AND TUESDAY MORNING CAUSING WINDS TO BECOME LIGHT AND VARIABLE. SOUTHERLY FLOW WILL RETURN TO LAKE MICHIGAN FOR AN EXTENDED PERIOD FROM WEDNESDAY THROUGH THE END OF THE WEEK. ALLSOPP && .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
216 PM CDT SAT OCT 5 2013 .DISCUSSION... 215 PM CDT LATE AFTERNOON AND EARLY EVENING...STORMS AND ASSOCIATED SEVERE POTENTIAL ARE THE INITIAL FOCUS WITH SHRA/TSRA COVERAGE OVERNIGHT THE SECOND FOCUS. SURFACE LOW PRESSURE REMAINS CENTERED OVER FAR EASTERN SOUTH DAKOTA WITH AN OCCLUDED FRONT ARCHING EAST THEN SOUTHEAST TO A VERY WEAK LOW CIRCULATION NORTHEAST OF DECORAH IOWA. A COLD FRONT THEN EXTENDS SOUTHWARD ACROSS THE QUAD CITIES BACK INTO CENTRAL MISSOURI AS NOTED BY THE SHARP DROP OFF IN DEWPOINTS. THERE IS ANOTHER TROUGH AHEAD OF THE FRONT WHICH MAY BE THE REMNANTS OF EARLIER OUTFLOW THAT MOVED ACROSS EASTERN MISSOURI. WATER VAPOR SHOWS SEVERAL UPPER SHORTWAVES MOVING NORTHEASTWARD AROUND THE EASTERN FLANK OF A BIG CLOSED UPPER LOW CENTERED OVER SOUTHEAST SOUTH DAKOTA. THE TRACK OF THESE WAVES WILL BE RIGHT ACROSS THE LOCAL AREA THROUGH TONIGHT. THE FIRST WAVE IS MOVING INTO EASTERN IOWA WITH ANOTHER WAVE OVER WEST CENTRAL MISSOURI. A THIRD WAVE IS MOVING ACROSS EASTERN OKLAHOMA AND WESTERN ARKANSAS. ADDITIONAL WAVES HAVE ALSO BEEN ROLLING NORTHEAST ACROSS THE LOWER OHIO VALLEY AND CENTRAL IL/IN. ALL OF THIS MAKES FOR A RATHER MESSY PRECIP SITUATION. CURRENT RADAR MOSAIC SHOWS SEVERAL CLUSTERS OF BETTER ORGANIZED CONVECTION MAINLY AFFECTING THE NORTHERN AND SOUTHEASTERN EXTENTS OF THE CWA TIED TO VARIOUS SHORTWAVES TRAVERSING THE UPPER FLOW. ADDITIONAL SPOTTY SHOWERS CONTINUE TO POP ACROSS THE CHICAGO METRO AREA WHERE STRATUS HAS BEEN ERODING AND INSTABILITY GROWING. THE NEXT WAVE COMING FROM EASTERN IOWA SEEMS TO BE DRIVING ANOTHER CLUSTER OF WEAKER BUT SLOWLY INTENSIFYING CONVECTION NEAR STERLING AND PERU. THE IMMEDIATE CONCERN IS THE MORE INTENSE STORMS MOVING INTO THE SOUTHEASTERN CWA AND THE WEAKER CLUSTER NEAR PERU/STERLING WHICH MAY INTENSIFY AS IT MOVES INTO THE CWA. WITH LOWEST CLOUDS ERODING SIGNALING EROSION OF EARLIER CAP ALONG WITH WARMING ATMOSPHERE IS BETTER PRIMED WITH MIXED LAYER CAPES AROUND 1500 J/KG. EFFECTIVE SHEAR HAS BEEN ABLE TO INTENSIFY BASED ON LATEST RAP ANALYSIS WITH AROUND 40 KT EXPECTED. STORMS THAT HAVE AFFECTED THE AREA THUS FAR HAVE EXHIBITED LOW AND MID LEVEL ROTATION THOUGH IT HAS BEEN WEAK. IT DOES APPEAR THAT COVERAGE WILL BEGIN TO EXPAND OUTSIDE AREAS THAT ARE CURRENTLY SEEING STORMS SO WILL CONTINUE TO MONITOR FOR SEVERE GIVEN THE SUPPORTIVE ATMOSPHERE. COVERAGE IS THE MAIN QUESTION HOWEVER...WITH OVERALL SEVERE THREAT STILL SEEMING ISOLATED-SCATTERED. THREATS REMAIN LARGE HAIL AND DAMAGING WIND GUSTS...WITH ISOLATED TORNADOES STILL POSSIBLE BUT AT THIS POINT WITH NORTHERN AREAS STILL FAVORED WITH LOCALLY BACKED FLOW A BETTER POSSIBILITY GIVEN THE WEAK LOW CIRCULATION JUST TO THE NORTHWEST...BUT HAVE SEEN SEVERAL SITES ACROSS THE CENTRAL AND EASTERN CWA BACK SLIGHTLY. VERY HIGH LOW LEVEL CAPE IS IN PLACE ACROSS MUCH OF THE AREA SO CANNOT DISCOUNT THE TORNADO THREAT ELSEWHERE. WITH PRECIPITABLE WATER VALUES OF 1.5-1.7+ INCHES HEAVY RAINFALL IS A CONCERN WITH ANY STRONGER STORMS. WITH RECENT DRY WEATHER AND UNCERTAINTY IN THE COVERAGE OF THE MOST INTENSE STORMS VS. LESS INTENSE BROADER RAIN/EMBEDDED THUNDER WILL HOLD OFF ON A FLASH FLOOD WATCH FOR NOW BUT CONTINUE TO MONITOR. TONIGHT...DURATION OF SEVERE POTENTIAL IS THE NEXT QUESTION. WITH THE FRONT VERY SLOWLY MOVING EASTWARD THE MOIST AIRMASS WILL REMAIN IN PLACE BUT SUNSET WILL LIKELY ALLOW INSTABILITY TO WANE SO SEVERE THREAT SHOULD BE DIMINISHING THROUGH THE EVENING. POPS HOWEVER LOOK TO REMAIN RATHER HIGH AS THE NEXT SEVERAL SHORTWAVES MOVE ACROSS. THUS EXPECT THAT THERE WILL BE A FEW MORE ROUNDS OF SHOWERS AND STORMS TO AFFECT THE AREA...WITH THE THUNDER THREAT DIMINISHING ACROSS THE WESTERN CWA AS THE FRONT APPROACHES. WILL NEED TO HANG ONTO POPS THROUGH MUCH OF THE NIGHT ACROSS THE EASTERN HALF OR SO OF THE CWA...NAMELY BECAUSE THE OK/AR WAVE IS EXPECTED TO ARRIVE AFTER MIDNIGHT BRINGING MORE SHRA/TSRA WITH IT. ULTIMATELY...POPS WILL DECREASE FROM WEST TO EAST OVERNIGHT...WITH A QUICKER EASTWARD PROGRESSION TOWARD DAYBREAK. DRIER AIR WILL BEGIN TO WORK INTO THE WEST WITH DEWPOINTS FALLING INTO THE 40S WEST AND 50S EAST OVERNIGHT. MDB SUNDAY THROUGH NEXT SATURDAY... LINGERING UPPER LEVEL CUT OFF LOW AND ASSOCIATED INSTABILITY SHOWERS INITIALLY WILL BE REPLACED BY HIGH PRESSURE AND A GRADUAL WARMING TREND LATER IN THE WEEK LASTING INTO SATURDAY. UPPER LOW TO TRUDGE ACROSS NORTHERN IL LATER SUNDAY AND SUNDAY NIGHT.. AND INTO NW INDIANA MONDAY MORNING. MODELS APPEAR TO CONTINUE TO STRUGGLE WITH THIS PROGRESSION WITH BOTH MODEL TO MODEL AND RUN TO RUN INCONSISTENCIES. 12Z GFS SEEMS SOMEWHAT A MIDDLE GROUND BETWEEN THE SLOWER NAM/CANADIAN AND FASTER ECMWF AND WILL TREND IN THIS DIRECTION WITH DETERMINISTIC FORECAST/GRIDS. THE MOST SIGNIFICANT WEATHER ELEMENT HAVING BEARING ON THE DEPARTURE SPEED OF THE UPPER LOW IS LIKELY THE DURATION OF THE CHANCE OF INSTABILITY SHOWERS ASSOCIATED WITH THE THERMAL TROUGH AND STEEPER LAPSE RATES WITH AND IN THE WAKE OF THE LOW. MIDDLE GROUND APPROACH WOULD HAVE INSTABILITY SHOWERS ENDING BY ABOUT DUSK MONDAY...BUT SHOULD A SLOWER SOLUTION LIKE THE NAM/CANADIAN VERIFY...WE COULD SEE ISOLATED SHOWERS LINGERING INTO TUESDAY. EVENING AND OVERNIGHT FORECAST SHIFTS WILL MONITOR AND ADJUST ACCORDINGLY. INITIAL RESIDUAL MOISTURE/LOW CLOUDS AND WIDELY SCT SHOWERS IN THE WAKE OF THE FRONT WILL EXIT EASTERN ILLINOIS AND NW INDIANA SUNDAY MORNING AS DRY SLOT PUNCHES INTO THE AREA FROM THE SW. GIVEN DRYING SW SFC FLOW EXPECT VARIABLE CONDITIONS SUNDAY WITH A FAIR AMOUNT OF SUNSHINE FOR A PERIOD AT MOST LOCATIONS AND DESPITE PASSAGE OF A COLD FRONT MAX TEMPS WILL STILL BE NEAR TO ONLY A FEW DEGREES BELOW SEASONAL NORMS. DEPENDING ON AFOREMENTIONED TIMING OF UPPER LOW... MAY SEE WIDELY SCATTERED INSTABILITY SHOWERS DEVELOP WEST OF I-39 LATE IN THE DAY. UPPER LEVEL THERMAL TROUGH TRAVERSES THE AREA EARLY MONDAY. GIVEN THE PRESENCE OF LIMITED MOISTURE... AND THIS OUT OF PHASE TIMING OF THE UPPER THERMAL TROUGH WITH THE MIN/MAX DIURNAL HEATING OF THE DAY... FEEL COVERAGE OF INSTABILITY SHOWERS ON MONDAY WILL BE SOMEWHAT LIMITED AND WILL CONTINUE TO PLAY LOW POPS FOR THAT EVENT. INCREASED CLOUDINESS ON MONDAY WILL LIMIT MAX TEMPS TO LOWER 60S.. WITH PERHAPS A FEW AREAS STAYING IN THE UPPER 50S. UPPER LEVEL HEIGHTS RISE RATHER ABRUPTLY IN THE WAKE OF THE UPPER CUT OFF LOW TUESDAY AS A PROGRESSIVE UPPER LEVEL RIDGE BUILDS EAST ACROSS THE PLAINS AND INTO THE WESTERN GREAT LAKES TUESDAY NIGHT INTO WEDNESDAY. THIS ALLOWS FOR ABUNDANT SUNSHINE AND MILDER TEMPS TO RETURN TO THE AREA ON TUESDAY... AND BE THE START OF A GRADUAL WARMING TREND THAT WILL LAST THROUGH THE REST OF THE WEEK. SPRAWLING HIGH PRESSURE WILL HELP ENABLE MOSTLY SUNNY MILD DAYS AND MOSTLY CLEAR...COOL...AND CRISP NIGHTS MID TO LATE WEEK. WITH THE HIGH SLIDING TO JUST EAST OF THE AREA THURS-SAT...AN EXTENDED PERIOD OF WEAK SOUTHERLY FLOW WILL ALLOW FOR TEMPS TO RETURN TO ABOVE SEASONAL AVERAGES AND ANOTHER STRETCH OF DELIGHTFUL AUTUMN WEATHER. THE NEXT CHANCE OF RAIN WILL THEN COME LATE SATURDAY OR SUNDAY. ED F && .AVIATION... //ORD AND MDW CONCERNS...UPDATED 18Z... * SOUTH WINDS ARND 10 KT WITH GUSTS ARND 15KT THIS AFTN. * SCATTERED THUNDERSTORMS EXPECTED AFT 19Z WITH MORE WIDESPREAD STORMS EXPECTED 20Z-23Z. SOME MAY BE STRONG TO SEVERE. * MODERATE RAIN THAT MAY CAUSE 6SM VSBY 00Z-03Z. * WINDS BECOME SW AFTER THE FRONT ALONG WITH MVFR CIGS IMPROVING TO VFR MID SUNDAY MORNING. JEE //DISCUSSION...UPDATED 18Z... VERY MESSY FORECAST FOR THIS AFTERNOON. THE SURFACE LOW IS OVER SE SOUTH DAKOTA...ITS WARM FRONT IS OVER SOUTHERN WISCONSIN...AND ITS COLD FRONT IS OVER EASTERN IOWA. STRATUS IS STILL HOLDING STRONG ACROSS THE REGION...BUT LOOKING OUT THE WINDOW HERE...A FEW HOLES ARE BEGINNING TO FORM. EXPECTING CIGS TO LIFT TO HIGH END MVFR BY 19Z. WHILE THE LOW CIGS HAVE CAUSED HAVOC WITH BREAK AWAY POINTS...IT IS LIMITING OUR MIXING AND HAVE LOWERED WIND GUSTS TO 15KT. THERE IS A CHANCE WE MAY NOT SEE ANY WIND GUSTS AT ALL THIS AFTN. IN ADDITION...INSTABILITY IS MUCH LOWER THAN INITIALLY THOUGHT DUE TO THE STRATUS. THEREFORE MADE SOME CHANGES TO TS CHANCES THIS AFTN. FIRST AT RFD...THINKING THE TSRA PASSING OVER THE TERMINAL NOW WILL BE THE MAIN SHOW. EXPECTING JUST SHOWERS AFT 20Z...AND THEN DRY CONDITIONS AFT 22Z. FOR THE EASTERN TERMINALS...TIMING OF THE CURRENT AREA OF SCT TS HAS THEM ARRIVING AT 19Z. WIDER COVERAGE IS EXPECTED BTWN 20Z AND 23Z. SOME OF THE STORMS MAY PULSE UP AND BECOME STRONG TO SEVERE...BUT WIDESPREAD SEVERE WEATHER IS NO LONGER EXPECTED. THE SOUPY ENVIRONMENT OUTSIDE WILL RESULT IN REDUCED VSBYS IF ANY STRONG SHOWERS OR TSRA PASS OVERHEAD. OBSERVED VSBYS RANGE FROM 2.5SM TO 5SM SO KEPT 3SM GOING. ADDITIONAL SHOWERS ARE EXPECTED BEHIND THE TSRA FOR A FEW HOURS...THROUGH 03Z. WINDS WILL BECOME SW TONIGHT ARND 8KT. DESPITE THE DRIER AIR MOVING INTO THE REGION BEHIND THE COLD FRONT...KEPT MVFR CIGS IN THE TAFS AFT 00Z. ON SATELLITE THERE IS A REGION OF MVFR CIGS JUST ALONG AND BEHIND THE FRONT. GUIDANCE INDICATES THAT THE MOISTURE WILL LINGER BEHIND THE FRONT WITH MVFR CIGS HOLDING ON. WITH NO GOOD REASON TO PULL THE CIGS...DECIDED TO LEAVE THEM IN. EXPECTING THE LOWER CIGS TO BURN OFF SUNDAY MORNING WITH SW WINDS 10-15KT. THERE WILL BE A WINDOW OF SCT TO CLEAR SKIES ASSOCIATED WITH THE LOWS DRY SLOT MOVING OVER THE TERMINALS TOMORROW WITH ANOTHER ROUND OF MVFR-VFR CIGS BEHIND IT. JEE //ORD AND MDW CONFIDENCE...UPDATED 18Z... * HIGH CONFIDENCE IN THUNDERSTORM TRENDS...MEDIUM-HIGH CONFIDENCE IN TIMING. * MEDIUM-LOW CONFIDENCE IN CIG HEIGHTS THIS EVENING AND OVERNIGHT. * HIGH CONFIDENCE IN ALL OTHER FORECAST ELEMENTS. JEE //OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z... SUNDAY NIGHT...PSBL MVFR CIGS AND CHC SHRA. MONDAY...MVFR CIGS/VSBYS WITH SHRA. PSBL POCKETS OF IFR CIGS. TUESDAY THROUGH FRIDAY...VFR. BEACHLER && .MARINE... 1228 PM CDT LOW PRESSURE WAS OVER EASTERN SOUTH DAKOTA THIS AFTERNOON WITH A WITH AN OCCLUDED FRONT INTO WISCONSIN AND A COLD FRONT EXTENDING SOUTH THROUGH ILLINOIS. THE COLD FRONT WILL MOVE THROUGH SOUTH AND CENTRAL LAKE MICHIGAN TONIGHT WITH PERIODS OF SHOWERS AND THUNDERSTORMS. THIS WILL TURN WINDS FROM SOUTH TO SOUTHWEST. STRONG EASTERLY FLOW WILL CONTINUE NORTH OF THE FRONT OVER NORTHERN LAKE MICHIGAN. THE FRONT WILL FINALLY REACH NORTHERN LAKE MICHIGAN SUNDAY AS THE LOW MOVES TO EASTERN LAKE SUPERIOR. THIS WILL ALLOW WINDS TO DIMINISH AND SHIFT SOUTH TO SOUTHWEST OVER THE NORTH END OF THE LAKE. THE LOW WILL CONTINUE TO LIFT NORTHEAST INTO EASTERN ONTARIO SUNDAY NIGHT AND MONDAY BUT A WEAK TROF OF LOW PRESSURE WILL REMAIN OVER LAKE MICHIGAN. AS THE TROF PASSES...WINDS WILL SHIFT TO NORTHWEST AND INCREASE MONDAY AFTERNOON. HIGH PRESSURE WILL GRADUALLY BUILD INTO THE WESTERN GREAT LAKES MONDAY NIGHT AND TUESDAY MORNING CAUSING WINDS TO BECOME LIGHT AND VARIABLE. SOUTHERLY FLOW WILL RETURN TO LAKE MICHIGAN FOR AN EXTENDED PERIOD FROM WEDNESDAY THROUGH THE END OF THE WEEK. ALLSOPP && .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
154 PM EDT SAT OCT 5 2013 .SYNOPSIS... ISSUED AT 342 AM EDT SAT OCT 5 2013 A LARGE LOW PRESSURE SYSTEM WILL BRING INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGH EARLY NEXT WEEK. THIS LOW PRESSURE SYSTEM WILL ALSO SEND A COLD FRONT THROUGH THE AREA WITH TEMPERATURES RETURNING TO NEAR NORMAL VALUES AFTER HIGHS IN THE LOW 80S AGAIN TODAY. && .UPDATE... ISSUED AT 1125 AM EDT SAT OCT 5 2013 A COUPLE OF SMALL SCALE EMBEDDED WAVES IN SOUTHWEST UPPER FLOW HAVE RESULTED IN CLUSTERS OF SHOWERS AND ISOLATED THUNDERSTORMS ACROSS CENTRAL/NORTHEAST INDIANA. ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO DEVELOP OTHER SOUTHERN LAKE MICHIGAN IN CLOSER PROXIMITY TO MORE PRONOUNCED UPPER LEVEL DIFFLUENCE DOWNSTREAM OF VIGOROUS NORTHERN PLAINS UPPER TROUGH. AREAS ROUGHLY ALONG AND SOUTHEAST OF A HUNTINGTON INDIANA TO FORT WAYNE INDIANA TO DEFIANCE LINE HAVE LIKELY RECEIVED BETWEEN A HALF INCH TO AN INCH OF RAINFALL SO FAR THIS MORNING. SOME OF THESE SAME LOCATIONS ACROSS NORTHWEST OHIO HAVE ALSO RECEIVED HEAVY RAINFALL YESTERDAY. GIVEN INCREASING CONFIDENCE IN SIGNIFICANT RAINFALL LATE TONIGHT INTO SUNDAY EVENING ALONG WITH RECENT HEAVY RAIN...WILL BE ISSUING A FLASH FLOOD WATCH SHORTLY FOR FAR NORTHEAST INDIANA...PORTIONS OF SOUTH CENTRAL LOWER MICHIGAN....AND ALL OF NORTHWEST OHIO COUNTIES FROM 06Z TONIGHT TO 06Z MONDAY. IN TERMS OF CONVECTIVE POTENTIAL...15Z RUC ANALYSIS DEPICTS 1000-1500 J/KG OF 100 HPA MLCAPES ACROSS MUCH OF WESTERN HALF OF THE AREA WITH 0 TO 6 KM BULK SHEAR VALUES IN THE 25 TO 30 KNOT RANGE. DESPITE SIGNIFICANT CLOUD COVER...DEEP MOISTURE PROFILES SHOULD CONTINUE TO YIELD CAPES ON THE ORDER OF 1000-1500 J/KG THIS AFTERNOON. DEEP LAYER SHEAR TO ALSO INCREASE LATE AFTERNOON ACROSS WESTERN HALF OF THE AREA AS A 500 HPA SPEED MAX LIFTS INTO NORTHWEST INDIANA AFTER 21Z. THUS...NO CHANGE IN THINKING FROM PREVIOUS FORECAST WITH LOW/ISOLATED SEVERE THREAT ACROSS ESPECIALLY WESTERN AREAS LATE AFTERNOON/EARLY EVENING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 342 AM EDT SAT OCT 5 2013 GRADUAL APPROACH OF IMPRESSIVE CLOSED OFF CYCLONIC GYRE EXTENDING THROUGH THE BULK OF THE TROPOSPHERE WILL BRING INCREASING CHANCES FOR RAIN THROUGH THE SHORT TERM PERIOD. SURFACE FRONTAL BOUNDARY EXTENDING INTO THE SOUTHERN GREAT LAKES WILL MOVE LITTLE THROUGH THE PERIOD WITH PERSISTENT THETA-E ADVECTION IN A LARGELY UNCAPPED ENVIRONMENT LEADING TO CONTINUED PERIODS OF CONVECTION. SMALL SCALE VORTICES IN SOUTHWEST FLOW ALOFT EMANATING FROM THE CENTRAL CONUS WILL ALSO SUPPORT INCREASING CHANCES FOR RAINFALL AS THE MAIN SYSTEM APPROACHES. OCCLUSION PROCESS IS ALREADY BEGINNING AND EARLIER NOTED SLOWING TREND HAS CONTINUED. MAIN SURFACE COLD FRONT IS NOT EXPECTED TO REACH OUR CWA UNTIL LATE TONIGHT. WILL STILL BE PLENTY OF RAIN AHEAD OF THE MAIN FRONT THOUGH. TIGHTENING LOW LEVEL MASS GRADIENT ASSOCIATED WITH APPROACHING PV ANOMALY WILL LEAD TO A STRENGTHENING OF THE LLJ AND A CORRESPONDING UPTICK IN 305K ISENTROPIC ASCENT. MOISTURE WILL CERTAINLY NOT BE LACKING EITHER. 305K MIXING RATIOS ARE ABOVE 8 G/KG AND PW VALUES ARE HOVERING AROUND 1.75 INCHES...NEAR THE 99TH PERCENTILE FOR THIS TIME OF YEAR BASED ON REGIONAL UPPER AIR CLIMATOLOGY. EXACT TIMING/PLACEMENT OF CONVECTION REMAINS HIGHLY UNCERTAIN BUT EXPECT COVERAGE TO INCREASE AS THE DAY WEARS ON GIVEN INCREASING DIURNAL INSTABILITY AND APPROACHING TROUGH. LATEST HI-RES GUIDANCE SHOWS CONVECTION NEAR INDIANAPOLIS WILL CONTINUE TO SPREAD NORTH THROUGH THE MORNING WITH A BRIEF BREAK BEFORE ADDITIONAL CONVECTION ARRIVES IN THE LATE AFTERNOON. TRIED TO INCORPORATE THIS INTO THE LATEST POP FORECAST BUT MAINTAINED FAIRLY BROADBRUSH APPROACH GIVEN UNCERTAINTY IN CONVECTIVE TRENDS. HIGHER CONFIDENCE THAT SHOWERS AND THUNDERSTORMS WILL BECOME WIDESPREAD BY TONIGHT THOUGH AS THE COLD FRONT APPROACHES...AND HAVE PUSHED POPS INTO CATEGORICAL VALUES. HIGHS TODAY WILL BE SIMILAR TO YESTERDAY...AS ANY BREAKS IN THE CLOUD COVER WILL ALLOW TEMPS TO MAKE A RUN AT THE MID 80S GIVEN WARM PROFILES ALOFT. LOWS TONIGHT WILL BE HIGHLY DEPENDENT ON EXACT TIMING OF FRONT BUT HAVE RAISED THEM A BIT IN ANTICIPATION OF A SLOWER FRONTAL PASSAGE. LAPSE RATES NEARLY MOIST ADIABATIC WILL LIKELY ONLY SUPPORT AROUND 1000 J/KG OR LESS OF SBCAPE TODAY. DEEP LAYER SHEAR IS ALSO MARGINAL DURING THE DAY AND EXPECT ONLY A SLIGHT CHANCE FOR SEVERE WEATHER...MAINLY IN AREAS THAT SEE A SUSTAINED PERIOD OF INSOLATION THAT ALLOWS INSTABILITY TO BUILD. SHEAR WILL INCREASE BY TONIGHT...BUT INSTABILITY WILL BE AT A MINIMUM AND AGAIN ONLY EXPECTING A LOW RISK OF SEVERE WEATHER AT THE MOMENT. HEAVY RAIN WILL LIKELY BE THE BIGGEST THREAT. A VERY MOIST ENVIRONMENT AND CONTINUED POTENTIAL FOR TRAINING STORMS COULD LEAD TO HIGH RAINFALL TOTALS BY THE TIME ALL IS SAID AND DONE EARLY NEXT WEEK. && .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 342 AM EDT SAT OCT 5 2013 RATHER DRAMATIC CHGS REQUIRED TO BEGIN THE PD ON ACCOUNT OF CONTD MODEL CONSENSUS SLWG IN EWD PROGRESSION OF PLAINS BOWLING BALL. INTERESTINGLY STILL SOME SIG SPREAD ALOFT STILL AT THIS TIME RANGE W/POSITION AND INTENSITY OF MID LVL CYCLONE WHICH RANGES FROM NRN IL IN NAM TO SRN IL IN GEM AT FHR60. REGARDLESS ENOUGH OF A CONSENSUS SIGNAL EXISTS TO EXTEND/BUMP POPS/WX THROUGH MON NIGHT. HWVR WILL FORGO ALLBLEND POP GUIDANCE FOR TUE IN LIGHT OF RAPID UPSTREAM HGT RISES FOLLOWING IN WAKE OF UPR TROUGH WHICH AT THAT POINT SHLD BE IN SE CANADA. OF GREATEST INTEREST W/SLWG SOLUTIONS ALOFT IS CONTD PUMP OF ANOMALOUS GOMEX MSTR FLUX INTO THE GREAT LAKES INADV OF MIDLVL CYCLONE WHICH SHOWS LTL SIGN OF WKNG UNTIL MON. SLWR EWD ADV OF FNTL BNDRY ALG W/PWS OF NEAR 1.8IN (99TH PERCENTILE) WOULD PREPOSE AT LEAST THE ERN HALF OF CWA FOR A CLASSIC MADDOX TYPE I HEAVY RAIN EVENT AND NOTED IN SVRL DETERMINISTIC QPF SOLUTIONS SUN-SUN NIGHT. SINCE THIS THREAT IS XPCD TO DVLP DY2 WILL FOLLOWUP PRIOR WELL DESERVED ESF. AS AN ASIDE...FAIR NUMBER OF SOLUTIONS DEPICT THE DVLPMNT OF A SFC FNTL WAVE SUN AFTN WHICH IF TRUE WOULD YIELD A HEIGHTENED RISK FOR LOW TOPPED SUPERCELLS ACRS ERN IN/WRN OH AND INHERENT TOR THREAT W/FVRBL OVERLAP OF MIXED LYR CAPE/SHEAR. OTRWS SWD TRENDING PROGRESSION OF AT LEAST MOD INTENSE MID LVL CYCLONE LEADS TO ADDNL ESCALATION/EXPANSION OF POPS MON AFTN/MON NIGHT. IN FACT SWD CNTRD CLUSTER OF SVRL SOLUTIONS INCLUDING GFS/GEM WOULD PORTEND A SECONDARY DEFORMATION ZONE DVLPG IN RESPONSE TO TRAILING FNTL WAVE MON NIGHT W/ASSUMED SEPARATION W/REMNANTS OF TS KAREN AS SOME SEMBLANCE OF THE TROWAL REMAINS INTACT. GIVEN ALL OF THE ABOVE...SIG CHGS TO TEMPS WERE MADE SUN/MON. HWVR SIG MODERATION STILL ON TAP IN WAKE OF THIS INTENSE SYS MID WEEK TIMED W/SECONDARY DEEP WRN TROUGH DVLPMNT AND DOWNSTREAM RIDGE AMPLIFICATION W/RTN TO ABV NORMAL TEMPS XPCD BY THU. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 145 PM EDT SAT OCT 5 2013 CONVECTION BEGINNING TO INCREASE IN COVERAGE FROM SOUTHERN ILLINOIS INTO SOUTHWEST LOWER MICHIGAN WITH A POCKET OF 1000-2000 J/KG OF 100 HPA MLCAPES ACROSS THE REGION. A COUPLE OF SHORT WAVES EMBEDDED IN SOUTHWEST UPPER FLOW WILL AID IN EXPANSION OF SHRA/TSRA COVERAGE THROUGH EARLY EVENING ACROSS NORTH CENTRAL INDIANA...WITH LIKELIHOOD OF SHOWERS AND EMBEDDED THUNDERSTORMS OVERSPREADING NORTHEAST INDIANA THROUGH THE EARLY TO LATE EVENING HOURS. DIURNAL MIXING HAS IMPROVED THE IFR CIGS TO MVFR AT KSBN EARLY THIS AFTERNOON. HAVE MAINTAINED TEMPO MVFR CONDS IN HEAVIER SHOWERS AND THUNDERSTORMS THIS AFTERNOON/EARLY EVENING...WITH TREND BACK TO IFR CONDITIONS LATE EVENING/HOUR NIGHT AS DEEPER MOISTURE LIFTS NORTHWARD INTO THE AREA. A BRIEF LULL IN COVERAGE OF SHOWERS AND THUNDERSTORMS IS POSSIBLE IN THE 04Z-08Z TIMEFRAME...BUT SHOULD INCREASE ONCE AGAIN TOWARD DAYBREAK AS LARGE SCALE FORCING/LOW LEVEL FRONTOGENESIS INCREASES WITH APPROACHING UPPER TROUGH && .IWX WATCHES/WARNINGS/ADVISORIES... IN...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR INZ007-009-018-026-027-033-034. MI...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR MIZ081. OH...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT FOR OHZ001-002-004-005-015-016-024-025. LM...NONE. && $$ UPDATE...MARSILI SYNOPSIS...AGD SHORT TERM...AGD LONG TERM...T 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 TOPEKA KS
323 PM CDT Sat Oct 5 2013 .SHORT TERM...(This Evening through Sunday) Issued at 320 PM CDT SAT OCT 5 2013 20Z water vapor imagery shows the closed upper low over southeast SD slowly propagating east. A shortwave trough axis has rotated through eastern KS helping to clear out the mid level clouds. At the surface the cold front had pushed well east and south with dry cool air advecting in from the west. For tonight and Sunday, the forecast calls for generally dry weather as there is little moisture to work with and large scale forcing should remain to the north and east of the forecast area. Did leave some slight chance pops in the far northeastern corner of the forecast area during the day Sunday. As the upper low drifts across southwest IA, lapse rates could steepen enough for some isolated showers to move across Nemaha and Brown counties. The main thing to watch will be the STRATOCU deck to the north. The RAP and NAM show these clouds eventually moving into much of the forecast area overnight. This should have an impact on MIN and MAX temps. Models are in good agreement that the boundary layer will remain well mixed overnight with increasing clouds from the north. Therefore am fairly confident that MIN temps will not fall below 40 and even tweaks temps up a degree or two. The forecast may still be on the cool side if the clouds move in quicker. Highs Sunday are expected to warm back into the 60s for most areas. Forecast soundings mix the boundary layer almost to 800MB and models indicate the cold air advection will have ended. The main question is whether clouds will hold temps down. Added about 3 to 5 degrees to MAX temps across the western and southern counties where there should be more insolation with good mixing. Across northeastern KS where clouds are likely to hang in tough, kept highs in the middle 50s. Wolters .LONG TERM...(Sunday Night through Saturday) Issued at 320 PM CDT SAT OCT 5 2013 Upper low still on track to progress eastward through the mid MO and OH river valleys through Monday. Most of the moisture wrapping around the backside of the exiting upper may linger across the far northeast corner of the cwa early Sunday evening...so have left a slight chance in for that time period. Otherwise will go with a dry fcst Monday through Thursday night as upper level ridging will develop across the plains in the wake of the first trough exiting trough and ahead of the second upper trough that deepens over the west CONUS. Will continue to slowly but steadily increase high temps through the 70s Monday through Thursday...with a few low 80s on Thursday. As the western trough then lift out into the plains on Friday and Friday night...with more clouds and the potential for showers and thunderstorms cooled temps slightly for Friday before the frontal passage and and even cooler readings in the low to middle 70s on Saturday. Warmed low temps from near 40 Monday morning into the 50s by Wednesday on through the end of the week. && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1209 PM CDT SAT OCT 5 2013 VFR forecast at KTOP/KFOE/KMHK with west winds gusting between 15 and 23 kts this afternoon. Winds stay up near 10 kts overnight as upper low passes to the northeast. Latest RAP and high res guidance are hinting at cigs redeveloping aft 08z at KMHK and 09z at KTOP/KFOE. Not confident enough to lower to MVFR however increased VFR cloud coverage at this time and will reevaluate MVFR potential at next issuance. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...63 AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1233 PM CDT Sat Oct 5 2013 ...Update to aviation forecast discussion... .SHORT TERM...(Today and Tonight) Issued at 316 AM CDT SAT OCT 5 2013 Closed upper level low is currently centered over central SD with a well defined mid level dry punch stretched across the central plains. Surface cold front responsible for yesterday`s thunderstorms has moved east into western MO. Trailing stratiform behind the main line of thunderstorms will continue for a few more hours in the far southeast cwa. An area of scattered showers with isolated thunder is working through parts of the cwa this morning due to some elevated instability rooted at around 750 mb. These showers will move northeast through the cwa during the next few hours exiting the area by sunrise. Cold dry air has begun to push into the region behind the front with temperatures in the mid 40s already in north central KS. Low temperatures tonight will range from the low 40s in north central KS to the upper 50s in east central KS. The winds have shifted to the west northwest and are forecast to increase to around 15 to 20 mph with gusts up to 30 mph during the day today. Clouds will continue to move east today with partly to mostly sunny skies expected by this afternoon and high temperatures in the upper 50s to low 60s. Cold air advection will persist through out the day today and tonight. The 850 mb temperatures will approach 0C later tonight therefore overnight low temperatures drop to around 40 across most of the area. .LONG TERM...(Sunday through Friday) Issued at 316 AM CDT SAT OCT 5 2013 Through Sunday afternoon the upper low is forecast to drop east southeast out from near Sioux Falls into Missouri. This takes an area of stratus and the colder air aloft across the northeastern counties. By afternoon hours, there is enough lift associated with the low to generate showers through the saturated layer in the column. In fact 850mb temperatures are running just near or below freezing, and soundings suggest the top of the lift in the column just clips where the -10/-20 layer is saturated aloft. However expect to see enough warmer air in the low levels to keep precip in the form of rain or a light drizzle. Could go on for a few hours in the afternoon, and would not be surprised to see some cold air funnels ad cold pool moves through. This will also keep high temperatures across the NE down int he 50s with 60s possible elsewhere. Mon-Fro continue to advertise a nice warm up through the end of the week as Monday starts out around 70 and Friday brings highs in the upper 70s. Lows Sunday night into Morning may be pretty chilly as skies clear and winds lighten before warm air advection returns. May see lows around 40 common over the area. These lows slowly moderate back into the 50s as southwesterly flow aloft returns to the plains and the next trof approaches the Rockies on Friday. Will carry just a slight chance for some pops mainly in the western counties. 67 && .AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon) Issued at 1209 PM CDT SAT OCT 5 2013 VFR forecast at KTOP/KFOE/KMHK with west winds gusting between 15 and 23 kts this afternoon. Winds stay up near 10 kts overnight as upper low passes to the northeast. Latest RAP and high res guidance are hinting at cigs redeveloping aft 08z at KMHK and 09z at KTOP/KFOE. Not confident enough to lower to MVFR however increased VFR cloud coverage at this time and will reevaluate MVFR potential at next issuance. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Sanders LONG TERM...67 AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS JACKSON KY
553 PM EDT SAT OCT 5 2013 .UPDATE... ISSUED AT 553 PM EDT SAT OCT 5 2013 SHOWERS/THUNDERSTORMS WHICH DEVELOPED IN CENTRAL KY HAVE HELD TOGETHER AS THEY MOVED INTO THE JKL FORECAST AREA...BUT WERE WEAKENING. UPDATED TO INCREASE POPS FOR EARLY THIS EVENING IN OUR NORTHERN COUNTIES. && .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 303 PM EDT SAT OCT 5 2013 COLD FRONT THROUGH THE AREA TONIGHT...SUNDAY...AND INTO THE DAY MONDAY. WILL CONCENTRATE ON TONIGHT THROUGH 0Z TUESDAY SINCE THIS IS WHEN THE MAIN ACTION WILL OCCUR. LATEST HI-RES MODEL GUIDANCE CONTINUES TO SHOW A SLOW PROGRESSION OF THE FRONT AND IT/S ASSOCIATED PRECIP. CREDIT PREVIOUS FORECAST FOR TAKING A SLOWER APPROACH OF THE SYSTEM...SINCE THIS SEEMS TO MATCH UP WELL WITH LATEST MODELS. AS IT IS...LATEST HRRR SHOWS SOME ISO PRECIP DEVELOPING ACROSS THE WESTERN EDGE OF THE CWA BY LATE THIS AFTERNOON...AHEAD OF THE MAIN LINE CURRENTLY LOCATED ACROSS FAR WESTERN KY...NORTH CENTRAL KY...AND PARTS OF INDIANA AND OHIO. WHAT CONVECTIVE INDUCED PRECIP THAT DOES DEVELOP WILL THEN DIE OFF WITH LOSS OF DAYTIME HEATING OVERNIGHT...AS THE MAIN LINE BEGINS ITS TREK SLIGHTLY EASTWARD. BY 15Z SUNDAY...THE LINE OF PRECIP WILL HAVE PROGRESSED TO CENTRAL KY AND EXPANDED ACROSS MUCH OF INDIANA AND WESTERN TN. IF THE LATEST NAM12 HOLDS TRUE...PRECIP CHANCES WILL NOT RE-ENTER THE CWA UNTIL AFTER THIS TIME. BY THIS POINT THE LINE WILL BE MOVING SLIGHTLY QUICKER...BUT WILL STILL HOLD ENOUGH MOISTURE TO DROP ABOUT AN INCH OF QPF IN IT/S DURATION. BY 0Z MONDAY...MUCH OF THE PRECIP SHOULD HAVE MOVED OUT OF THE REGION. HOWEVER...TROPICAL STORM KAREN...MOVING NE FROM THE GULF OF MEXICO...WILL BEGIN MERGING WITH THE LOW PRESSURE SYSTEM. THIS WILL CAUSE THE FRONT TO STALL OUT ONCE MORE ACROSS THE MORE MOUNTAINOUS AREAS TO OUR EAST...WITH HEAVY RAINS EXPECTED. ALTHOUGH THE UPPER LEVEL PATTERN IS IN FAIRLY GOOD AGREEMENT UP UNTIL THIS POINT...BY 0Z MONDAY THE PLACEMENT OF THE UPPER LEVEL TROUGH STARTS TO SHIFT DEPENDING ON THE MODEL. IF IT PASSES JUST A BIT FARTHER NORTH THAN THE OHIO RIVER...ALL RAIN CHANCES WILL CEASE BY 0Z TUESDAY. HOWEVER...IF THE LATEST NAM IS CORRECT...IT WILL TRACK THE LOW JUST A BIT FURTHER SOUTHWARD. ENOUGH TO CAUSE SOME WRAP AROUND MOISTURE ACROSS THE FAR NORTHERN SECTIONS OF THE STATE AS IT STALLS OUT. AT THIS POINT IT SEEMS AS THOUGH THIS WRAP AROUND MOISTURE WILL STAY JUST TO OUR WEST. AS FOR INSTABILITY...FOR THIS AFTERNOON AND TOMORROW AFTERNOON...WILL PROBABLY SEE THE BEST CHANCE FOR ANY ISOLATED TO SCT THUNDERSTORM DEVELOPMENT. HOWEVER SOUNDINGS STILL LOOK WEAK AT BEST FOR THIS TO HAPPEN. AS A RESULT...WILL NOT RULE OUT A FEW RUMBLES OF THUNDER HERE AND THERE WITH ANY SCT SHOWERS...BUT THE MAIN CONCERN WILL STILL BE THE RAINS. AS WAS NOTED BY THE PREVIOUS FORECASTER...THERE IS SOME MID/LEVEL DRYING IN THE LATEST NAM SOUNDINGS...SO SOME WINDY DOWNBURSTS COULD NOT BE OUT OF THE QUESTION. THAT BEING SAID...BY 3Z MONDAY...FORECAST SOUNDINGS SHOW A COMPLETELY SATURATED AIR MASS...LEADING TO THE LOSS OF CONVECTIVE ABILITY AND TURNING TO A MORE STRATIFORM EVENT AS THE MAIN LINE PASSES OVER. DRY AIR WILL FINALLY START TO WORK IN FOR MONDAY MORNING...BRINGING AN END TO ANY LINGERING PRECIP. AS FOR TEMPERATURES...AFTER A WARM START TO TODAY THANKS TO WARM AND MOIST SOUTHERLY FLOW...EXPECT SIMILAR CONDITIONS TOMORROW. THIS WILL HELP TO FURTHER INITIATE ANY SCT CONVECTION OUT AHEAD OF THE MAIN LINE OF SHOWERS. ONCE THE MAIN LINE OF SHOWERS STARTS MOVING INTO THE REGION DURING THE AFTERNOON HOURS...CONTINUOUS RAIN WILL BEGIN DROPPING THE TEMPERATURES FROM WEST TO EAST. AS A RESULT...HIGHS WILL BE MET EARLY ON...REACHING THE HIGHEST VALUES IN THE FAR EAST. ONCE THE FRONT PASSES THROUGH ON MONDAY...COLD AIR WILL FILTER IN BEHIND AND TEMPERATURES WILL START FALLING BEFORE THEY ARE ABLE TO REACH THEIR MAXIMUM POTENTIAL. HIGHS WILL ONLY REACH THE LOW TO MID 60S BY EARLY AFTERNOON BEFORE THEY START DROPPING BACK DOWN. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 245 PM EDT SAT OCT 5 2013 ANY LINGERING SHOWERS IN THE FAR EAST WILL BE ENDING EARLY MONDAY EVENING. THEN WITH THE COLD FRONT WELL TO OUR EAST AND SURFACE HIGH PRESSURE BUILDING INTO THE AREA MONDAY NIGHT WE WILL SEE COOL TEMPERATURES AND DRY WEATHER FOR THE START OF THE FORECAST PERIOD. IN THE WAKE OF THE EXITING UPPER LOW TO OUR NORTHEAST EARLY IN THE WEEK...RESIDUAL TROUGHING WILL GIVE WAY TO RISING HEIGHTS AS UPPER RIDGING GRADUALLY BUILDS INTO THE OH VALLEY. WITH UPPER RIDGING REMAINING OVER THE AREA INTO NEXT WEEKEND AND SURFACE HIGH PRESSURE SHIFTING TO OUR EAST WE WILL SEE SLOWLY WARMING TEMPERATURES AS THE WEEK CONTINUES...ESPECIALLY FOR MAXIMUMS. ALSO THE PATTERN WILL BE CONDUCIVE FOR RIDGE VALLEY TEMPERATURE DIFFERENCES FOR OVERNIGHT MINIMUMS...WITH INCREASING DIURNAL TEMPERATURE RANGES ESPECIALLY IN THE VALLEYS LATER IN THE WEEK. THE COMING WEEK WILL BE DRY WITH THE NEXT CHANCE FOR RAIN HOLDING OFF UNTIL THE APPROACH OF THE NEXT COLD FRONT WHICH IS STILL MORE THAN SEVEN DAYS AWAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 119 PM EDT SAT OCT 5 2013 A LARGE AREA OF LOW PRESSURE OFF TO OUR NE HAS SPAWNED A STRONG COLD FRONT AND A LARGE AREA OF PRECIPITATION TO ACCOMPANY IT. THIS PRECIP IS CURRENTLY IMPACTING WESTERN KY...AND PORTIONS OF TN AND OHIO. THE LINE WILL CONTINUE TO SLOWLY PUSH EASTERLY AHEAD OF THE COLD FRONT...REACHING THE TAF SITES SOMETIME TOMORROW AFTERNOON. IF MODELS CONTINUE WITH ONGOING SOLUTIONS...PRECIP SHOULD NOT ARRIVE AT TAF LOCATIONS UNTIL AFTER THE FORECAST PERIOD. HOWEVER...PUT IN SOME VCSH AT KSME AND KLON JUST IN CASE THINGS DO IN FACT SPEED UP AND TO ACCOUNT FOR ANY PRECIP WHICH MAY DEVELOP OUT AHEAD OF THE MAIN LINE. WITH THAT IN MIND...SOME OF THE HI-RES MODELS ARE ALSO POINTING AT SOME DEVELOPING ISL TO SCT CONVECTION THIS AFTERNOON AS WELL. BUT WITH NO EVIDENCE OF ANY SH/TSRA DEVELOPMENT AT THIS TIME IN OUR CWA...CONFIDENCE ON WHETHER OR NOT THESE CONVECTIVE CELLS WILL AFFECT THE TAF SITES IS QUITE LOW...SO CHOSE TO LEAVE OUT AT TAFS. IMPOSING CLOUD COVER TONIGHT SHOULD BE ENOUGH TO KEEP ANY FOG POTENTIAL AT BAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...JMW LONG TERM...SBH AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
303 PM EDT SAT OCT 5 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 303 PM EDT SAT OCT 5 2013 COLD FRONT THROUGH THE AREA TONIGHT...SUNDAY...AND INTO THE DAY MONDAY. WILL CONCENTRATE ON TONIGHT THROUGH 0Z TUESDAY SINCE THIS IS WHEN THE MAIN ACTION WILL OCCUR. LATEST HI-RES MODEL GUIDANCE CONTINUES TO SHOW A SLOW PROGRESSION OF THE FRONT AND IT/S ASSOCIATED PRECIP. CREDIT PREVIOUS FORECAST FOR TAKING A SLOWER APPROACH OF THE SYSTEM...SINCE THIS SEEMS TO MATCH UP WELL WITH LATEST MODELS. AS IT IS...LATEST HRRR SHOWS SOME ISO PRECIP DEVELOPING ACROSS THE WESTERN EDGE OF THE CWA BY LATE THIS AFTERNOON...AHEAD OF THE MAIN LINE CURRENTLY LOCATED ACROSS FAR WESTERN KY...NORTH CENTRAL KY...AND PARTS OF INDIANA AND OHIO. WHAT CONVECTIVE INDUCED PRECIP THAT DOES DEVELOP WILL THEN DIE OFF WITH LOSS OF DAYTIME HEATING OVERNIGHT...AS THE MAIN LINE BEGINS ITS TREK SLIGHTLY EASTWARD. BY 15Z SUNDAY...THE LINE OF PRECIP WILL HAVE PROGRESSED TO CENTRAL KY AND EXPANDED ACROSS MUCH OF INDIANA AND WESTERN TN. IF THE LATEST NAM12 HOLDS TRUE...PRECIP CHANCES WILL NOT RE-ENTER THE CWA UNTIL AFTER THIS TIME. BY THIS POINT THE LINE WILL BE MOVING SLIGHTLY QUICKER...BUT WILL STILL HOLD ENOUGH MOISTURE TO DROP ABOUT AN INCH OF QPF IN IT/S DURATION. BY 0Z MONDAY...MUCH OF THE PRECIP SHOULD HAVE MOVED OUT OF THE REGION. HOWEVER...TROPICAL STORM KAREN...MOVING NE FROM THE GULF OF MEXICO...WILL BEGIN MERGING WITH THE LOW PRESSURE SYSTEM. THIS WILL CAUSE THE FRONT TO STALL OUT ONCE MORE ACROSS THE MORE MOUNTAINOUS AREAS TO OUR EAST...WITH HEAVY RAINS EXPECTED. ALTHOUGH THE UPPER LEVEL PATTERN IS IN FAIRLY GOOD AGREEMENT UP UNTIL THIS POINT...BY 0Z MONDAY THE PLACEMENT OF THE UPPER LEVEL TROUGH STARTS TO SHIFT DEPENDING ON THE MODEL. IF IT PASSES JUST A BIT FARTHER NORTH THAN THE OHIO RIVER...ALL RAIN CHANCES WILL CEASE BY 0Z TUESDAY. HOWEVER...IF THE LATEST NAM IS CORRECT...IT WILL TRACK THE LOW JUST A BIT FURTHER SOUTHWARD. ENOUGH TO CAUSE SOME WRAP AROUND MOISTURE ACROSS THE FAR NORTHERN SECTIONS OF THE STATE AS IT STALLS OUT. AT THIS POINT IT SEEMS AS THOUGH THIS WRAP AROUND MOISTURE WILL STAY JUST TO OUR WEST. AS FOR INSTABILITY...FOR THIS AFTERNOON AND TOMORROW AFTERNOON...WILL PROBABLY SEE THE BEST CHANCE FOR ANY ISOLATED TO SCT THUNDERSTORM DEVELOPMENT. HOWEVER SOUNDINGS STILL LOOK WEAK AT BEST FOR THIS TO HAPPEN. AS A RESULT...WILL NOT RULE OUT A FEW RUMBLES OF THUNDER HERE AND THERE WITH ANY SCT SHOWERS...BUT THE MAIN CONCERN WILL STILL BE THE RAINS. AS WAS NOTED BY THE PREVIOUS FORECASTER...THERE IS SOME MID/LEVEL DRYING IN THE LATEST NAM SOUNDINGS...SO SOME WINDY DOWNBURSTS COULD NOT BE OUT OF THE QUESTION. THAT BEING SAID...BY 3Z MONDAY...FORECAST SOUNDINGS SHOW A COMPLETELY SATURATED AIRMASS...LEADING TO THE LOSS OF CONVECTIVE ABILITY AND TURNING TO A MORE STRATIFORM EVENT AS THE MAIN LINE PASSES OVER. DRY AIR WILL FINALLY START TO WORK IN FOR MONDAY MORNING...BRINGING AN END TO ANY LINGERING PRECIP. AS FOR TEMPERATURES...AFTER A WARM START TO TODAY THANKS TO WARM AND MOIST SOUTHERLY FLOW...EXPECT SIMILAR CONDITIONS TOMORROW. THIS WILL HELP TO FURTHER INITIATE ANY SCT CONVECTION OUT AHEAD OF THE MAIN LINE OF SHOWERS. ONCE THE MAIN LINE OF SHOWERS STARTS MOVING INTO THE REGION DURING THE AFTERNOON HOURS...CONTINUOUS RAIN WILL BEGIN DROPPING THE TEMPERATURES FROM WEST TO EAST. AS A RESULT...HIGHS WILL BE MET EARLY ON...REACHING THE HIGHEST VALUES IN THE FAR EAST. ONCE THE FRONT PASSES THROUGH ON MONDAY...COLD AIR WILL FILTER IN BEHIND AND TEMPERATURES WILL START FALLING BEFORE THEY ARE ABLE TO REACH THEIR MAXIMUM POTENTIAL. HIGHS WILL ONLY REACH THE LOW TO MID 60S BY EARLY AFTERNOON BEFORE THEY START DROPPING BACK DOWN. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 245 PM EDT SAT OCT 5 2013 ANY LINGERING SHOWERS IN THE FAR EAST WILL BE ENDING EARLY MONDAY EVENING. THEN WITH THE COLD FRONT WELL TO OUR EAST AND SURFACE HIGH PRESSURE BUILDING INTO THE AREA MONDAY NIGHT WE WILL SEE COOL TEMPERATURES AND DRY WEATHER FOR THE START OF THE FORECAST PERIOD. IN THE WAKE OF THE EXITING UPPER LOW TO OUR NORTHEAST EARLY IN THE WEEK...RESIDUAL TROUGHING WILL GIVE WAY TO RISING HEIGHTS AS UPPER RIDGING GRADUALLY BUILDS INTO THE OH VALLEY. WITH UPPER RIDGING REMAINING OVER THE AREA INTO NEXT WEEKEND AND SURFACE HIGH PRESSURE SHIFTING TO OUR EAST WE WILL SEE SLOWLY WARMING TEMPERATURES AS THE WEEK CONTINUES...ESPECIALLY FOR MAXIMUMS. ALSO THE PATTERN WILL BE CONDUCIVE FOR RIDGE VALLEY TEMPERATURE DIFFERENCES FOR OVERNIGHT MINIMUMS...WITH INCREASING DIURNAL TEMPERATURE RANGES ESPECIALLY IN THE VALLEYS LATER IN THE WEEK. THE COMING WEEK WILL BE DRY WITH THE NEXT CHANCE FOR RAIN HOLDING OFF UNTIL THE APPROACH OF THE NEXT COLD FRONT WHICH IS STILL MORE THAN SEVEN DAYS AWAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 119 PM EDT SAT OCT 5 2013 A LARGE AREA OF LOW PRESSURE OFF TO OUR NE HAS SPAWNED A STRONG COLD FRONT AND A LARGE AREA OF PRECIPITATION TO ACCOMPANY IT. THIS PRECIP IS CURRENTLY IMPACTING WESTERN KY...AND PORTIONS OF TN AND OHIO. THE LINE WILL CONTINUE TO SLOWLY PUSH EASTERLY AHEAD OF THE COLD FRONT...REACHING THE TAF SITES SOMETIME TOMORROW AFTERNOON. IF MODELS CONTINUE WITH ONGOING SOLUTIONS...PRECIP SHOULD NOT ARRIVE AT TAF LOCATIONS UNTIL AFTER THE FORECAST PERIOD. HOWEVER...PUT IN SOME VCSH AT KSME AND KLON JUST IN CASE THINGS DO IN FACT SPEED UP AND TO ACCOUNT FOR ANY PRECIP WHICH MAY DEVELOP OUT AHEAD OF THE MAIN LINE. WITH THAT IN MIND...SOME OF THE HI-RES MODELS ARE ALSO POINTING AT SOME DEVELOPING ISL TO SCT CONVECTION THIS AFTERNOON AS WELL. BUT WITH NO EVIDENCE OF ANY SH/TSRA DEVELOPMENT AT THIS TIME IN OUR CWA...CONFIDENCE ON WHETHER OR NOT THESE CONVECTIVE CELLS WILL AFFECT THE TAF SITES IS QUITE LOW...SO CHOSE TO LEAVE OUT AT TAFS. IMPOSING CLOUD COVER TONIGHT SHOULD BE ENOUGH TO KEEP ANY FOG POTENTIAL AT BAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JMW LONG TERM...SBH AVIATION...JMW
AREA FORECAST DISCUSSION
NWS JACKSON KY
301 PM EDT SAT OCT 5 2013 .SHORT TERM...(THIS EVENING THROUGH MONDAY) ISSUED AT 301 PM EDT SAT OCT 5 2013 ALL MODELS ARE STILL ON TRACK TO BRING US A POTENT AND SLOW MOVING COLD FRONT THROUGH THE AREA TONIGHT...SUNDAY...AND INTO THE DAY MONDAY. WILL CONCENTRATE ON TONIGHT THROUGH 0Z MONDAY SINCE THIS IS WHEN THE MAIN ACTION WILL OCCUR. LATEST HI-RES MODEL GUIDANCE CONTINUES TO SHOW A SLOW PROGRESSION OF THE FRONT AND IT/S ASSOCIATED PRECIP. CREDIT PREVIOUS FORECAST FOR TAKING A SLOWER APPROACH OF THE SYSTEM...SINCE THIS SEEMS TO MATCH UP WELL WITH LATEST MODELS. AS IT IS...LATEST HRRR SHOWS SOME ISO PRECIP DEVELOPING ACROSS THE WESTERN EDGE OF THE CWA BY LATE THIS AFTERNOON...AHEAD OF THE MAIN LINE CURRENTLY LOCATED ACROSS FAR WESTERN KY...NORTH CENTRAL KY...AND PARTS OF INDIANA AND OHIO. WHAT CONVECTIVE INDUCED PRECIP THAT DOES DEVELOP WILL THEN DIE OFF WITH LOSS OF DAYTIME HEATING OVERNIGHT...AS THE MAIN LINE BEGINS ITS TREK SLIGHTLY EASTWARD. BY 15Z SUNDAY...THE LINE OF PRECIP WILL HAVE PROGRESSED TO CENTRAL KY AND EXPANDED ACROSS MUCH OF INDIANA AND WESTERN TN. IF THE LATEST NAM12 HOLDS TRUE...PRECIP CHANCES WILL NOT RE-ENTER THE CWA UNTIL AFTER THIS TIME. BY THIS POINT THE LINE WILL BE MOVING SLIGHTLY QUICKER...BUT WILL STILL HOLD ENOUGH MOISTURE TO DROP ABOUT AN INCH OF QPF IN IT/S DURATION. BY 0Z MONDAY...MUCH OF THE PRECIP SHOULD HAVE MOVED OUT OF THE REGION. HOWEVER...TROPICAL STORM KAREN...MOVING NE FROM THE GULF OF MEXICO...WILL BEGIN MERGING WITH THE LOW PRESSURE SYSTEM. THIS WILL CAUSE THE FRONT TO STALL OUT ONCE MORE ACROSS THE MORE MOUNTAINOUS AREAS TO OUR EAST...WITH HEAVY RAINS EXPECTED. ALTHOUGH THE UPPER LEVEL PATTERN IS IN FAIRLY GOOD AGREEMENT UP UNTIL THIS POINT...BY 0Z MONDAY THE PLACEMENT OF THE UPPER LEVEL TROUGH STARTS TO SHIFT DEPENDING ON THE MODEL. IF IT PASSES JUST A BIT FARTHER NORTH THAN THE OHIO RIVER...ALL RAIN CHANCES WILL CEASE BY 0Z TUESDAY. HOWEVER...IF THE LATEST NAM IS CORRECT...IT WILL TRACK THE LOW JUST A BIT FURTHER SOUTHWARD. ENOUGH TO CAUSE SOME WRAP AROUND MOISTURE ACROSS THE FAR NORTHERN SECTIONS OF THE STATE AS IT STALLS OUT. AT THIS POINT IT SEEMS AS THOUGH THIS WRAP AROUND MOISTURE WILL STAY JUST TO OUR WEST. AS FOR INSTABILITY...FOR THIS AFTERNOON AND TOMORROW AFTERNOON...WILL PROBABLY SEE THE BEST CHANCE FOR ANY ISOLATED TO SCT THUNDERSTORM DEVELOPMENT. HOWEVER SOUNDINGS STILL LOOK WEAK AT BEST FOR THIS TO HAPPEN. AS A RESULT...WILL NOT RULE OUT A FEW RUMBLES OF THUNDER HERE AND THERE WITH ANY SCT SHOWERS...BUT THE MAIN CONCERN WILL STILL BE THE RAINS. AS WAS NOTED BY THE PREVIOUS FORECASTER...THERE IS SOME MID/LEVEL DRYING IN THE LATEST NAM SOUNDINGS...SO SOME WINDY DOWNBURSTS COULD NOT BE OUT OF THE QUESTION. THAT BEING SAID...BY 3Z MONDAY...FORECAST SOUNDINGS SHOW A COMPLETELY SATURATED AIRMASS...LEADING TO THE LOSS OF CONVECTIVE ABILITY AND TURNING TO A MORE STRATIFORM EVENT AS THE MAIN LINE PASSES OVER. DRY AIR WILL FINALLY START TO WORK IN FOR MONDAY MORNING...BRINGING AN END TO ANY LINGERING PRECIP. AS FOR TEMPERATURES...AFTER A WARM START TO TODAY THANKS TO WARM AND MOIST SOUTHERLY FLOW...EXPECT SIMILAR CONDITIONS TOMORROW. THIS WILL HELP TO FURTHER INITIATE ANY SCT CONVECTION OUT AHEAD OF THE MAIN LINE OF SHOWERS. ONCE THE MAIN LINE OF SHOWERS STARTS MOVING INTO THE REGION DURING THE AFTERNOON HOURS...CONTINUOUS RAIN WILL BEGIN DROPPING THE TEMPERATURES FROM WEST TO EAST. AS A RESULT...HIGHS WILL BE MET EARLY ON...REACHING THE HIGHEST VALUES IN THE FAR EAST. ONCE THE FRONT PASSES THROUGH ON MONDAY...COLD AIR WILL FILTER IN BEHIND AND TEMPERATURES WILL START FALLING BEFORE THEY ARE ABLE TO REACH THEIR MAXIMUM POTENTIAL. HIGHS WILL ONLY REACH THE LOW TO MID 60S BY EARLY AFTERNOON BEFORE THEY START DROPPING BACK DOWN. .LONG TERM...(MONDAY NIGHT THROUGH SATURDAY) ISSUED AT 245 PM EDT SAT OCT 5 2013 ANY LINGERING SHOWERS IN THE FAR EAST WILL BE ENDING EARLY MONDAY EVENING. THEN WITH THE COLD FRONT WELL TO OUR EAST AND SURFACE HIGH PRESSURE BUILDING INTO THE AREA MONDAY NIGHT WE WILL SEE COOL TEMPERATURES AND DRY WEATHER FOR THE START OF THE FORECAST PERIOD. IN THE WAKE OF THE EXITING UPPER LOW TO OUR NORTHEAST EARLY IN THE WEEK...RESIDUAL TROUGHING WILL GIVE WAY TO RISING HEIGHTS AS UPPER RIDGING GRADUALLY BUILDS INTO THE OH VALLEY. WITH UPPER RIDGING REMAINING OVER THE AREA INTO NEXT WEEKEND AND SURFACE HIGH PRESSURE SHIFTING TO OUR EAST WE WILL SEE SLOWLY WARMING TEMPERATURES AS THE WEEK CONTINUES...ESPECIALLY FOR MAXIMUMS. ALSO THE PATTERN WILL BE CONDUCIVE FOR RIDGE VALLEY TEMPERATURE DIFFERENCES FOR OVERNIGHT MINIMUMS...WITH INCREASING DIURNAL TEMPERATURE RANGES ESPECIALLY IN THE VALLEYS LATER IN THE WEEK. THE COMING WEEK WILL BE DRY WITH THE NEXT CHANCE FOR RAIN HOLDING OFF UNTIL THE APPROACH OF THE NEXT COLD FRONT WHICH IS STILL MORE THAN SEVEN DAYS AWAY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 119 PM EDT SAT OCT 5 2013 A LARGE AREA OF LOW PRESSURE OFF TO OUR NE HAS SPAWNED A STRONG COLD FRONT AND A LARGE AREA OF PRECIPITATION TO ACCOMPANY IT. THIS PRECIP IS CURRENTLY IMPACTING WESTERN KY...AND PORTIONS OF TN AND OHIO. THE LINE WILL CONTINUE TO SLOWLY PUSH EASTERLY AHEAD OF THE COLD FRONT...REACHING THE TAF SITES SOMETIME TOMORROW AFTERNOON. IF MODELS CONTINUE WITH ONGOING SOLUTIONS...PRECIP SHOULD NOT ARRIVE AT TAF LOCATIONS UNTIL AFTER THE FORECAST PERIOD. HOWEVER...PUT IN SOME VCSH AT KSME AND KLON JUST IN CASE THINGS DO IN FACT SPEED UP AND TO ACCOUNT FOR ANY PRECIP WHICH MAY DEVELOP OUT AHEAD OF THE MAIN LINE. WITH THAT IN MIND...SOME OF THE HI-RES MODELS ARE ALSO POINTING AT SOME DEVELOPING ISL TO SCT CONVECTION THIS AFTERNOON AS WELL. BUT WITH NO EVIDENCE OF ANY SH/TSRA DEVELOPMENT AT THIS TIME IN OUR CWA...CONFIDENCE ON WHETHER OR NOT THESE CONVECTIVE CELLS WILL AFFECT THE TAF SITES IS QUITE LOW...SO CHOSE TO LEAVE OUT AT TAFS. IMPOSING CLOUD COVER TONIGHT SHOULD BE ENOUGH TO KEEP ANY FOG POTENTIAL AT BAY. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...JMW LONG TERM...SBH AVIATION...JMW
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
353 PM CDT SAT OCT 5 2013 .SYNOPSIS... ISSUED AT 315 PM CDT SAT OCT 5 2013 OCCLUDED AND VERTICALLY STACKED LOW WAS SPINNING OVER SOUTHEAST SODAK THIS AFTERNOON. AN OCCLUDED FRONT AT THE SFC STRETCHES FROM NEAR AXN...DOWN TO THE NRN TWIN CITIES METRO AND SOUTHEAST FROM THERE TO A TRIPLE POINT IN SW WISCONSIN. THIS LOW HAS STARTED TO SLIP ESE TOWARD SW MN THIS AFTERNOON. THIS IS ALLOWING THE BLIZZARD THAT HAS BEEN RAGING FOR THE BETTER PART OF 3 DAYS ACROSS THE NRN HIGH PLAINS TO SLOWLY WIND DOWN TODAY...WITH AN IMPRESSIVE BANK OF SNOW SHOWING UP ON VIS SATELLITE THIS AFTERNOON ACROSS WYOMING INTO WRN NEB/SODAK. .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 315 PM CDT SAT OCT 5 2013 STRONG MID LEVEL JET HAS ROUNDED THE BASE OF THE STACKED LOW OVER SODAK TODAY. THIS HAS HELPED ENHANCE MID-LEVEL TEMP GRADIENTS ACROSS THE AREA. THIS HAS RESULTED IN AN ENHANCED AREA OF FGEN DEVELOPING IN THE H7 TO H5 LAYER...MIX IN SOME ADIABATIC OMEGA ON THE 305K SFC AND YOU GET THE DEVELOPING BAND OF SHOWERS ACROSS THE TWIN CITIES METRO AT 300 PM. THE HRRR ALONG WITH THE HOPWRF HAVE BEEN CONSISTENT IN DEVELOPING THIS FEATURE ALL DAY...SO FOLLOWED THESE MODELS CLOSELY TO MOVE THIS BAND OF PRECIP THROUGH ERN AND CENTRAL MN AND WRN WI THIS EVENING INTO TONIGHT. STILL HAVE BEST LI/S BETWEEN 0 AND -2 OVER WRN WI..SO HAVE SOME ISO THUNDER WORDING IN THE EAST THIS AFTERNOON. THIS ALSO MATCHES UP WELL WITH WHERE THE HRRR IS DEVELOPING MORE ROBUST CONVECTION. THOUGH WE ARE NOT EXPECTING ANY SEVERE WEATHER...COOLER TEMPERATURES ALOFT MOVING IN FROM THE SOUTHWEST HAS RESULTED IN SOME GRAUPEL/SMALL HAIL BEING REPORTED THIS AFTERNOON...WHICH WILL CONTINUE TO BE THE CASE THROUGH THIS EVENING BEFORE WE LOOSE THE CONVECTIVE ASPECT OF THE PRECIP AND IT BECOMES MAINLY STRATIFORM. FOR TONIGHT...THE BIG QUESTION IS WHETHER OR NOT SKIES TRY TO CLEAR OUT AGAIN ACROSS THE SOUTH AS THE DEVELOPING PRECIP BAND MOVES INTO CENTRAL MN AND NW WI. TO SOME EXTENT...THE NAM/ECMWF/GFS ALL SHOW SKIES CLEARING OUT TONIGHT FOR AT LEAST A PERIOD FROM SRN MN INTO WRN WI. THE NAM IS THE MOST AGGRESSIVE WITH THIS...WITH LOWS DOWN INTO THE 30S FROM SOUTH CENTRAL MN UP INTO WRN WI. BESIDE THE COOLER TEMPS...IF SKIES DO CLEAR OUT LIKE THAT...THEN THOSE CLEAR SKIES WOULD LIKELY FILL IN WITH DENSE FOG...SO THAT WILL NEED TO BE WATCHED AS WE GO THROUGH THE NIGHT. FOR SUNDAY...THINGS ARE LOOKING UP WEATHER WISE FOR THE TWIN CITIES MARATHON IN THE MORNING...AS PRECIP LOOKS TO HOLD OFF IN THE TWIN CITIES UNTIL THE AFTERNOON. BY 12Z THE LOW WILL HAVE FILLED IN TO THE POINT WHERE IT WILL BE A RATHER BROAD AREA OF LOW PRESSURE EXTENDING FROM SW MN UP INTO THE WRN UP OF MICH. COLD CONVEYOR BELT PRECIP BY SUNDAY MORNING WILL STRETCH ACROSS NRN WI ACROSS CENTRAL/NRN MN...THEN DOWN ACROSS THE ERN DAKOTAS...ALMOST WRAPPING AROUND THE MPX AREA. AS SFC AND UPPER AIR FEATURES DRIFT TOWARD THE GREAT LAKES DURING THE DAY...THE WRN EDGE OF THE PRECIP WILL BEGIN MOVING ACROSS THE AREA. USED A BLEND OF THE GEM/NAM/SREF TO BRING THIS PRECIP BACK EAST ACROSS THE AREA SUNDAY...THIS RESULTED IN A SLOWING OF THE EWD PROGRESSION OF POPS TOMORROW. IN FACT...MOST OF THE 12Z GUIDANCE KEEPS PRECIP THROUGH 7 PM SUNDAY EVENING WEST OF WISCONSIN...SO A FURTHER SLOWING IN POP GRIDS MAY BE NEEDED TONIGHT. OTHER CHANGE FOR SUNDAY WAS TO LOWER TEMPS A BIT...ESPECIALLY ACROSS MN. WITH MOSTLY CLOUDY CONDITIONS EXPECTED TO PREVAIL...WILL BE A STRUGGLE FOR MUCH OF THE MN AREA TO CRACK 50 FOR HIGHS. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 315 PM CDT SAT OCT 5 2013 AS THE SHORT TERM MENTIONED...THE UPPER LOW CONTINUES TO SLOW AND LOW POPS REMAIN IN PLACE OVER ERN/SRN MN AND WRN WI INTO SUNDAY NIGHT. CLEARING WILL GRADUALLY TAKE PLACE AND IT IS POSSIBLE TO GET AREAS OF FOG BY MONDAY MORNING DEPENDING ON TIMING OF CLEARING AND STRENGTH OF WIND. ANOTHER LONG STRETCH OF LATE SUMMER WEATHER WILL TAKE HOLD NEXT WEEK...PARTICULARLY TUESDAY ONWARD AS A DIGGING WEST COAST TROUGH LEADS TO A LARGE RIDGE BUILDING EASTWARD ACROSS THE PLAINS. STRONG RETURN FLOW AND GUSTY SOUTH WINDS TUESDAY WILL EASE MID/LATE WEEK AS A BAGGIER PRESSURE PATTERN DEVELOPS UNDER THE RIDGE. 925 MB TEMPS REACH THE MID/UPPER TEENS CELSIUS FOR MUCH OF NEXT WEEK...BRINGING HIGHS FIRMLY INTO THE 70S. GUIDANCE IS IN STRONG AGREEMENT FOR MID 70S...INCLUDING THE CLIMATOLOGICALLY FAVORING MOS PRODUCT AT EXTENDED RANGES. HIGHS AND LOWS WILL BE ABOUT 15 DEGREES ABOVE AVERAGE WITH NEARLY UNRESTRICTED SUNSHINE EACH DAY THROUGH THURSDAY. ANOTHER POTENT STORM SYSTEM WILL DEVELOP TO THE LEE OF THE ROCKIES THURSDAY NIGHT AND TRACK NORTHWARD INTO THE DAKOTAS FRIDAY NIGHT. THIS SHOULD KEEP THE MAJORITY OF THE AREA DRY THROUGH FRIDAY BEFORE THE COLD FRONT SWINGS THROUGH FRIDAY NIGHT. OVERALL...THE GFS AND ECMWF REMAIN IN RATHER GOOD AGREEMENT SO FORECAST CONFIDENCE IS HIGH THROUGHOUT THE LONG TERM PERIOD. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1239 PM CDT SAT OCT 5 2013 LOW CONFIDENCE WITH CIG FORECAST IN TAFS. DRYING ASSOCIATED WITH OCCLUDED LOW OVER SE SODAK HAS BEEN SLOWLY SPREADING NORTH/EAST. THE RAP ALONG WITH THE GFS/NAM TAKES VFR CONDITIONS ACROSS ALL TERMINALS FOR A TIME. THERE IS LOTS OF DISAGREEMENT WITH WHEN MVFR CIGS WILL DROP BACK SOUTH AND EAST THIS EVENING...WITH RAP BEING THE MOST AGGRESSIVE WITH BRINGING MVFR OR LOWER CIGS BACK AND THE GFS/NAM SIGNIFICANTLY SLOWER. THESE TAFS WERE WRITTEN MORE TOWARD THE GFS/NAM IDEA FOR CIGS. CONFIDENCE INCREASING IN AN AREA OF SHRA DEVELOPING SHORTLY FROM STC DOWN TO MKT ON EAST FOR THE AFTERNOON. THE HRRR ALONG WITH THE HOPWRF HAVE BOTH BEEN DEPICTING THIS ALL MORNING AND WITH MID LEVEL CLOUDS EXPANDING ON SATELLITE ALONG WITH RETURNS SHOWING UP ON RADAR IN SOUTH CENTRAL MN...SIDED CLOSELY WITH THE HRRR IN BRINGING PRECIP BACK TO ALL BUT RWF. THE LOW OFF TO THE WEST WILL DRIFT ACROSS MN TONIGHT...WITH WINDS BECOMING LIGHT AND VRB AS A RESULT. WITH THE LIGHT WINDS... ANYWHERE THAT REMAINS RELATIVELY CLEAR TONIGHT WILL HAVE TO THREAT FOR DENSE FOG. AT THE MOMENT...THE MOST LIKELY PLACE FOR THAT TO HAPPEN WOULD BE OVER WRN WI. KMSP...TOUGH TO PIN DOWN THE CIGS FOR THIS FORECAST...AS THE 12Z NAM/GFS WOULD BOTH INDICATE THAT CIGS WILL REMAIN VFR UNTIL LATE SUNDAY AFTERNOON. CONFIDENCE HIGH IN ANOTHER ROUND OF SHOWERS MOVING ACROSS THE FIELD BETWEEN 20Z AND 01Z PER THE HRRR AND HOPWRF...THOUGH CONFIDENCE LOWER IN CIGS COMING BACK DOWN AS LOW AS THEY ARE CURRENTLY FORECAST TO BE...MAY ONLY COME AS LOW AS 6K FT WITH THE PRECIP. OPTIMISTIC CIG FORECAST TOMORROW BASED ON THE GFS/NAM...BUT THE RAP SHOWS MVFR CIGS RETURNING TO MSP AROUND 09Z. IF THE CIGS DO COME IN BEFORE 12Z SUNDAY...THERE IS A GOOD CHANCE THEY WILL COME IN BELOW 017. /OUTLOOK FOR KMSP/ MON...VFR...MVFR POSSIBLE EARLY. WINDS NW 5-10 KT. TUE...VFR. WINDS S 15G25 KT. WED...VFR. WINDS SSE 10-15 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ SYNOPSIS...MPG SHORT TERM...MPG LONG TERM...BORGHOFF AVIATION...MPG
AREA FORECAST DISCUSSION
NWS DULUTH MN
320 PM CDT SAT OCT 5 2013 .SHORT TERM...(THIS EVENING THROUGH SUNDAY) ISSUED AT 319 PM CDT SAT OCT 5 2013 STACKED LOW PRESSURE OVER SOUTHEAST SOUTH DAKOTA WILL MOVE EAST/SOUTHEAST TONIGHT...ALTHOUGH THE SURFACE LOW IS FORECAST TO MOVE TOWARD UPPER MICHIGAN TONIGHT. AS THE SURFACE LOW NEARS THE NORTHLAND LATER TONIGHT...WINDS SHOULD GRADUALLY SUBSIDE. WE CONTINUE TO GET GUSTS OF 35 TO 45 MPH AT THE HEAD OF LAKE SUPERIOR...AND WE`LL EXTEND THE WIND ADVISORY FOR DOUGLAS...SOUTHERN SAINT LOUIS...CARLTON...AND SOUTHERN LAKE COUNTIES UNTIL 10 PM. THE STRONGEST WINDS WILL REMAIN WILL BE CLOSE TO LAKE SUPERIOR. RAIN WAS DEVELOPING ACROSS PORTIONS OF CENTRAL/SOUTHEAST MINNESOTA SIMILAR TO WHAT THE MODELS INCLUDING THE HRRR WERE DEPICTING. WE SHOULD CONTINUE TO SEE RAIN DEVELOP AND MOVE NORTH THROUGH THE NORTHLAND THIS EVENING/OVERNIGHT...BECOMING WIDESPREAD. WE`VE SEEN A FEW LIGHTNING STRIKES CLOSE TO THE AREA...SO ADDED A SLIGHT CHANCE FOR A STORM TO ALL AREAS LATE THIS AFTERNOON/EARLY EVENING...THEN TO EASTERN AREAS THROUGH LATE EVENING. SOME FOG WILL ALSO BE POSSIBLE...ESPECIALLY AROUND THE LAKE AND AS THE GRADIENT RELAXES. THERE WILL BE A CONTINUED CHANCE FOR SHOWERS ON SUNDAY...ALTHOUGH COVERAGE WILL BE LESS THAN WHAT HAS OCCURRED TODAY AND WHAT IS EXPECTED TONIGHT. THERE SHOULD STILL BE PLENTY OF CLOUDS AROUND THOUGH...AND THE MODELS CONTINUE TO SHOW PLENTY OF LOW LEVEL MOISTURE REMAINING. THE EXCEPTION WILL BE PORTIONS OF OUR SOUTHEAST ZONES EARLY...AND OUR FAR NORTHWEST ZONES LATE. HIGHS SUNDAY WILL RANGE FROM 55 TO 60 OVER OUR WESTERN/SOUTHEAST ZONES...WITH AREAS BETWEEN AROUND 50. .LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY) ISSUED AT 319 PM CDT SAT OCT 5 2013 TAIL END OF A DEPARTING LOW PRESSURE SYSTEM OVER THE GREAT LAKES WILL ALLOW A FEW LIGHT RAIN SHOWERS TO LINGER ACROSS THE ERN HALF OF THE FORECAST AREA SUNDAY NIGHT INTO EARLY MONDAY MORNING. RAINFALL AMTS WILL BE LOW. HIGH PRESSURE WILL BUILD IN ACROSS THE UPPER MIDWEST MONDAY AND TUESDAY WITH QUIET WEATHER CONDITIONS AND WARMER TEMPERATURES. SKIES WILL REMAIN MOSTLY SUNNY EARLY IN THE WEEK BEFORE A WEAK SFC FRONT SLIDES ACROSS THE NRN PLAINS AND USHERS IN ADDITIONAL CLOUD COVER WED AND THURSDAY...MAINLY OVER THE NRN COUNTIES. THE UPPER RIDGE OVER THE ERN US WILL AMPLIFY LATE IN THE WEEK AS A TROUGH IN THE WEST DEEPENS THROUGH THE ROCKIES. THIS UPPER LOW WILL EVENTUALLY MOVE INTO THE MIDWEST BY THE WEEKEND AND BRING ADDITIONAL CHANCES FOR PRECIPITATION. TEMPERATURES WILL REMAIN ABOVE AVERAGE THIS WEEK WITH VERY MILD AFTERNOON HIGHS IN THE 60S AND LOWER 70S. OVERNIGHT LOWS EARLY IN THE WEEK WILL BE SLIGHTLY CHILLY INTO THE 30S AND LOWER 40S...BUT RISE INTO THE UPPER 40S AND LOWER 50S BY THE LATTER HALF OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1232 PM CDT SAT OCT 5 2013 IFR AND MVFR CIGS/VSBYS WILL PERSIST THROUGH TODAY AND MOST OF TONIGHT BEFORE GRADUAL IMPROVEMENT IS SEEN BY LATE SUNDAY MORNING ACROSS THE WRN TERMINALS. LIGHT SCATTERED RAIN SHOWERS ARE EXPECTED THIS AFTERNOON WITH MORE WIDESPREAD HEAVIER SHOWERS POSSIBLE THIS EVENING...AFTER 23/00Z...LASTING THROUGH 05/06Z. VSBYS WILL LOWER IN THE STRONGER SHOWERS...WITH POSSIBLY PATCHY FOG AROUND DLH AND HYR TONIGHT. GUSTY NE WINDS WILL SLOWLY DIMINISH IN INTENSITY AND BACK TO THE NORTH TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... DLH 47 51 40 62 / 90 60 20 10 INL 39 55 37 62 / 60 40 0 0 BRD 46 51 39 65 / 80 60 10 0 HYR 46 56 40 61 / 80 50 30 10 ASX 49 54 43 62 / 80 60 40 10 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR MNZ020-037. WI...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR WIZ001. LS...GALE WARNING UNTIL 10 PM CDT THIS EVENING FOR LSZ141>147. SMALL CRAFT ADVISORY UNTIL 10 AM CDT SUNDAY FOR LSZ121-140-148. && $$ SHORT TERM...MELDE LONG TERM...BJT AVIATION...BJT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
111 PM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 1034 AM CDT SAT OCT 5 2013 A TRICKY FORECAST TO SAY THE LEAST FOR TODAY. DRY SLOT HAS MOVED IN BEHIND THE OCCLUDED FRONT THIS MORNING...WITH PARTIAL CLEARING OF SKIES SEEN WEST AND SOUTH OF THE TWIN CITIES. AFTER MAKING GOOD PROGRESS OVERNIGHT...THIS CLEARING HAS PUT ON THE BREAKS AS THE LOW OVER SE SODAK HAS STARTED TO DRIFT ESE. THIS WILL KEEP THE CLEARING FROM MAKING IT MUCH FARTHER NORTH...BUT IT WILL CONTINUE TO SLOWLY CRAWL TOWARD THE EAST TODAY. OF COURSE AS THIS IS GOING ON THE BIGGEST CHANGE TO THE FORECAST IS THE ADDITION OF SHOWERS THIS AFTERNOON FROM MANKATO TO ST. CLOUD ON EAST. THE HRRR HAS BEEN SHOWING THIS AREA OF SHOWERS DEVELOPING BACK TO THE WEST FOR SEVERAL RUNS NOW. LOOKING AT THE RAP...THIS IS IN RESPONSE TO A STRONG BAND OF FGEN COMING UP FROM IOWA IN THE H7-H5 LAYER. LOOKING DOWN TO THE SOUTHWEST ON SATELLITE...YOU CAN SEE THIS AREA OF PRECIP STARTING TO TAKE SHAPE FROM ERN KANSAS UP INTO WRN IOWA. BOOSTED POPS UP TO AROUND 50 PERCENT BACK TO THE CITIES THIS AFTERNOON...BUT IF THE HRRR IS CORRECT...MAY NEED TO BOOST THEM UP SIGNIFICANTLY IN THE NEAR FUTURE...ESPECIALLY CONSIDERING ALL 4 MEMBERS OF THE 05.09 HOPWRF SHOW SOMETHING SIMILAR HAPPENING. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 342 AM CDT SAT OCT 5 2013 THE POTENCY OF THIS EARLY FALL SYSTEM WAS AGAIN ON DISPLAY LAST NIGHT WITH STRONG TO SEVERE STORMS IN THE WARM SECTOR AND A RAGING BLIZZARD IN WESTERN SOUTH DAKOTA. FURTHERMORE...THE SYSTEM HAS BEEN OCCLUDED FOR 12-18 HOURS NOW AND WE STILL SAW A 1-2 MB MSLP PRESSURE DROP OVERNIGHT. THE TROWAL IS CREATING A HOME RUN HITTING DEFORMATION BAND FROM NORTHERN MN TO ND TO SD. IN FACT...THE PRECIP SHIELD ALONG THE COLD CONVEYOR BELT ACTUALLY EXTENDS ALL THE WAY FROM WYOMING TO MICHIGAN...AND THUNDERSTORMS ALONG THE COLD FRONT EXTEND FROM MICHIGAN TO TEXAS. NOT A SMALL SYSTEM BY ANY MEANS. THE FORECAST AREA WILL FIND ITSELF IN THE DRY SLOT MOST OF THE DAY TODAY AND ALSO TONIGHT TO SOME DEGREE. HOWEVER SOME DRIZZLE IS POSSIBLE AND THE CLOUDS SHOULD LARGELY STAY IN TACT. THE OCCLUDED BOUNDARY ISN`T GOING ANYWHERE...ESPECIALLY FOR CENTRAL MN/WI. SOUTHERN PORTIONS OF THE FORECAST AREA /THAT`S RIGHT...SOUTHERN/ ARE CLOSER TO THE COLDER AND DRIER AIR...SO THERE IS A BETTER CHANCE OF AT LEAST PARTIAL CLEARING TODAY IN SOUTHERN MN. MUCH COLDER AIR ALOFT ARRIVES TONIGHT...SO THE STRATUS WON`T BE FAR BEHIND EVEN IF THERE IS CLEARING DURING THE DAY TODAY. THE 00-06Z GUIDANCE IS TOO FAR SOUTH WITH THE DEFORMATION PRECIP BAND THIS MORNING...AS THE FORECAST AREA IS VIRTUALLY PRECIP FREE. IT`S ALSO NOT DEEP ENOUGH WITH THE SURFACE LOW. TRIED TO KEEP THE POPS TODAY ON THE OUTER EDGES OF THE FORECAST AREA TO COUNTER THIS AND ALSO TO STAY CLOSE TO SURROUND FORECAST OFFICES. OTHERWISE...WINDS WILL FALL OFF AS THE LOW SLOWLY FILLS AND MOVES OVERHEAD. IF THE CLOUDS CLEAR ANYWHERE TONIGHT...FOG COULD BE A PROBLEM...TOOK THE SIDE OF LOW STRATUS FOR NOW. NEAR STEADY TEMPERATURE TODAY SO MADE LITTLE ADJUSTMENT TO THE PREVIOUS FORECAST. WE ADJUSTED DEWPOINTS BY KEEPING SLIGHTLY HIGHER VALUES NEAR THE FRONT AND COOLER VALUES CLOSER TO THE DRY SLOT. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 342 AM CDT SAT OCT 5 2013 THE SFC LOW FROM THE POTENT/DEEP SYSTEM AFFECTING THE REGION WILL SHIFT INTO WI BY DAYBREAK SUN MRNG WHILE THE LOW PRES CENTER ALOFT WILL SHIFT SE INTO NRN IA. AS THESE TWO LOWS MOVE EAST IN TANDEM SLOWLY DURG THE DAY ON SUN...THE DRY SLOT OVER MUCH OF THE AREA WILL FILL BACK IN WITH DEEPER MOISTURE WRAPPING AROUND THE UPPER LEVEL LOW. COLD ALOFT COMBINED WITH LOW LEVEL WINDS SHIFTING TO A MORE NLY DIRECTION WILL AID IN KEEPING LOW CLOUDS IN PLACE FOR MUCH OF THE DAY...ALONG WITH A DRIZZLE/RAIN SCENARIO FOR SENSIBLE WX. THE UPPER LOW WILL SHIFT ESE INTO CENTRAL IL BY MON MRNG...DRAGGING MUCH OF THE MOISTURE WITH IT BUT THERE WILL STILL BE A CHC FOR LINGERING SHOWERS IN WRN WI ON MON WHILE SRN/CENTRAL MN STARTS TO CLEAR OUT. CONDS WILL GRADUALLY IMPROVE DURG THE DAY ON MON AS HIGH PRES FROM SW CANADA DROPS IN. DESPITE THE COOL ORIGIN OF THIS AIRMASS...IT WILL BE QUICKLY MODIFIED BY AN UPPER LEVEL RIDGE THAT WITH INCRG H5 HEIGHTS WILL SPELL A WARMING TREND ALONG WITH A PROLONGED DRYING-OUT PERIOD FOR THE AREA. DRY WX IS FORECAST MON THRU THU WITH HIGHS RISING BACK INTO THE MID 70S. MODELS CONTINUE TO ADVERTISE ANOTHER POTENT SYNOPTIC-SCALE LOW PRES SYSTEM TO DEVELOP IN THE LEE OF THE ROCKIES THU NIGHT INTO FRI MORNING...WITH IT QUICKLY MOVG NEWD INTO THE DAKOTAS FRI. THIS MAY ALLOW FOR SOME MID-TO-LATE DAY SHWRS/TSTMS OVER WRN MN ON FRI AS THIS SYSTEM ADVANCES. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1239 PM CDT SAT OCT 5 2013 LOW CONFIDENCE WITH CIG FORECAST IN TAFS. DRYING ASSOCIATED WITH OCCLUDED LOW OVER SE SODAK HAS BEEN SLOWLY SPREADING NORTH/EAST. THE RAP ALONG WITH THE GFS/NAM TAKES VFR CONDITIONS ACROSS ALL TERMINALS FOR A TIME. THERE IS LOTS OF DISAGREEMENT WITH WHEN MVFR CIGS WILL DROP BACK SOUTH AND EAST THIS EVENING...WITH RAP BEING THE MOST AGGRESSIVE WITH BRINGING MVFR OR LOWER CIGS BACK AND THE GFS/NAM SIGNIFICANTLY SLOWER. THESE TAFS WERE WRITTEN MORE TOWARD THE GFS/NAM IDEA FOR CIGS. CONFIDENCE INCREASING IN AN AREA OF SHRA DEVELOPING SHORTLY FROM STC DOWN TO MKT ON EAST FOR THE AFTERNOON. THE HRRR ALONG WITH THE HOPWRF HAVE BOTH BEEN DEPICTING THIS ALL MORNING AND WITH MID LEVEL CLOUDS EXPANDING ON SATELLITE ALONG WITH RETURNS SHOWING UP ON RADAR IN SOUTH CENTRAL MN...SIDED CLOSELY WITH THE HRRR IN BRINGING PRECIP BACK TO ALL BUT RWF. THE LOW OFF TO THE WEST WILL DRIFT ACROSS MN TONIGHT...WITH WINDS BECOMING LIGHT AND VRB AS A RESULT. WITH THE LIGHT WINDS... ANYWHERE THAT REMAINS RELATIVELY CLEAR TONIGHT WILL HAVE TO THREAT FOR DENSE FOG. AT THE MOMENT...THE MOST LIKELY PLACE FOR THAT TO HAPPEN WOULD BE OVER WRN WI. KMSP...TOUGH TO PIN DOWN THE CIGS FOR THIS FORECAST...AS THE 12Z NAM/GFS WOULD BOTH INDICATE THAT CIGS WILL REMAIN VFR UNTIL LATE SUNDAY AFTERNOON. CONFIDENCE HIGH IN ANOTHER ROUND OF SHOWERS MOVING ACROSS THE FIELD BETWEEN 20Z AND 01Z PER THE HRRR AND HOPWRF...THOUGH CONFIDENCE LOWER IN CIGS COMING BACK DOWN AS LOW AS THEY ARE CURRENTLY FORECAST TO BE...MAY ONLY COME AS LOW AS 6K FT WITH THE PRECIP. OPTIMISTIC CIG FORECAST TOMORROW BASED ON THE GFS/NAM...BUT THE RAP SHOWS MVFR CIGS RETURNING TO MSP AROUND 09Z. IF THE CIGS DO COME IN BEFORE 12Z SUNDAY...THERE IS A GOOD CHANCE THEY WILL COME IN BELOW 017. /OUTLOOK FOR KMSP/ MON...VFR...MVFR POSSIBLE EARLY. WINDS NW 5-10 KT. TUE...VFR. WINDS S 15G25 KT. WED...VFR. WINDS SSE 10-15 KT. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ UPDATE...MPG SHORT TERM...CLF LONG TERM...JPC AVIATION...MPG
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1232 PM CDT SAT OCT 5 2013 .UPDATE... ISSUED AT 1232 PM CDT SAT OCT 5 2013 UPDATED FOR AVIATION DISCUSSION. UPDATE ISSUED AT 1029 AM CDT SAT OCT 5 2013 THE SURFACE LOW WAS LOCATED IN SOUTHEAST SOUTH DAKOTA AS OF 15Z WITH AN OCCLUDED FRONT EXTENDING FROM THIS LOW ACROSS PORTIONS OF S-C MINNESOTA INTO FAR SOUTHWEST WISCONSIN. 925MB BOUNDARY IS IN NEARLY THE SAME LOCATION WITH HIGHER THETA-E AIR NORTH AND EAST OF THE BOUNDARY. THIS FRONT MARKED A CLEARING LINE WITH DRY CONDITIONS BEHIND IT OVER MUCH OF SOUTHERN MINNESOTA. LIGHT RAIN/DRIZZLE CONTINUED OVER PORTIONS OF THE NORTHLAND THIS MORNING...BUT WASN`T REAL WIDESPREAD. WE TRIMMED BACK SOME ON POPS THROUGH MID AFTERNOON BUT MAY HAVE TO FURTHER AS SEVERAL OBSERVATIONS WERE NOT REPORTING ANY RAIN AS OF 15Z. WE DO EXPECT AN INCREASE IN COVERAGE LATER THIS AFTERNOON AS THE STACKED LOW PRESSURE SYSTEM MOVES FURTHER EAST. THE LATEST HRRR WAS DOING A DECENT JOB DEPICTING THE LIGHT RAIN THIS MORNING AND SHOWS COVERAGE INCREASING QUITE A BIT MID TO LATE AFTERNOON ACROSS THE SOUTHERN THIRD...THEN FURTHER NORTH THIS EVENING. THE 12Z NAM SUPPORTS THE HRRR BUT STILL MAY BE OVERDONE WITH IT`S QPF. AREAS OF DRIZZLE WILL ALSO OCCUR AROUND LAKE SUPERIOR. WE CONTINUE TO MONITOR RADAR TRENDS AND LATEST MODEL OUTPUT AND ADJUST AS NEEDED. IT REMAINS WINDY AROUND LAKE SUPERIOR...ESPECIALLY FROM SILVER BAY TO THE TWIN PORTS AND ALONG THE BAYFIELD PENINSULA. KDLH WAS GUSTING TO 42 MPH AS OF THE 1008 AM OBSERVATION AND TO 46 MPH ON PARK POINT. WE`LL KEEP THE WIND ADVISORY GOING AS IS FOR NOW. WE MAY NEED TO EXTEND IT FOR THE TWIN PORTS AREA TO TWO HARBORS/SILVER BAY. THE WIND WASN`T AS STRONG ACROSS BAYFIELD/ASHLAND COUNTIES BUT SOME HIGHER GUSTS WILL REMAIN POSSIBLE THERE AS WELL. && .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 410 AM CDT SAT OCT 5 2013 AT 4 AM...RAIN CONTINUED TO MOVE NORTHWARD ACROSS THE CWA. THE MASSIVE LOW PRESSURE SYSTEM WAS LOCATED IN CENTRAL SOUTH DAKOTA...WITH AN OCCLUDED FRONT STRETCHING EASTWARD THROUGH SW MN. TEMPERATURES AT 4 AM WERE GENERALLY IN THE MID TO UPPER 40S NORTH AND LOWER TO MIDDLE 50S SOUTH. STRONG WINDS CONTINUED NEAR LAKE SUPERIOR...WITH KDYT AND KDLH STILL GUSTING ABOVE 40 MPH. THE RAIN HAD DIMINISHED CONSIDERABLY ACROSS THE SOUTHERN THIRD OF THE CWA BUT CONTINUED FROM THE TWIN PORTS NORTHWARD. THE MAIN FOCUS FOR TODAY THROUGH SUNDAY IS THE EXTENT AND TIMING OF VARIOUS WAVES OF PRECIPITATION. THE NAM AND THE NSSL AND NCEP WRF RUNS SEEM TO HAVE A DECENT HANDLE ON THE SITUATION. THEY ALL BRING A REPRIEVE IN THE RAIN TO THE SOUTHERN CWA...BEFORE INCREASING AGAIN THIS AFTERNOON. DESPITE SOME BREAKS IN THE PRECIPITATION...THERE SHOULD BE AREAS OF DRIZZLE AS WELL. WILL CONTINUE WITH HIGH POPS. A LITTLE CONCERNED WE MAY NEED TO EVENTUALLY PULL BACK ON POPS IN THE SOUTH...BUT KEPT THEM HIGH DUE TO THE POTENTIAL FOR DRIZZLE. RAIN SHOULD BECOME WIDESPREAD AGAIN TONIGHT...AS SURFACE LOW PRESSURE RE-FORMS OVER WISCONSIN. FOR THAT REASON...WILL CONTINUE WITH HIGH POPS TONIGHT...AND THEN GRADUALLY DECREASE IN PLACE AS THE LOW STARTS TO FALL APART ON SUNDAY. WILL CONTINUE POPS THROUGHOUT THE DAY THOUGH...AS THERE SHOULD BE SOME LINGERING PRECIPITATION. WILL CONTINUE WITH THE WIND ADVISORY FOR TODAY DUE TO THE STRONG EASTERLY WINDS COMING OFF LAKE SUPERIOR. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 410 AM CDT SAT OCT 5 2013 ANOMALOUS SFC/MID LVL LOW WILL DRIFT EAST OF REGION BE EARLY MONDAY AS SPLIT FLOW IN WESTERLIES ALLOWS NRN BRANCH TO DEEPEN OVER REGION. PRECIP WILL GRADUALLY DIMINISH OVER THE ERN CWA AS CYCLONIC CIRCULATION LOOSENS ITS GRIP MONDAY. MDLS AGREE THAT A RELATIVELY QUIET DRY WEATHER PATTERN WILL COMMENCE TUESDAY AND PERSIST THROUGH THE WEEK. SYNOPTIC PATTERN WILL FEATURE A DEVELOPING LARGE AMPLITUDE UPPER TROF OVER CALIFORNIA WITH A BROAD UPPER RIDGE ACROSS THE NRN PLAINS AND THE WRN GT LAKES. A SFC TROUGH WILL BEGIN TO FORM OVER THE PLAINS AND EXTEND NORTH INTO NWRN MN BY WED EVENING. ALTHOUGH A WARM ADVECTION REGIME WILL BECOME MORE PRONOUNCED ACROSS THE CWA AT THIS TIME IT APPEARS THE MORE FAVORABLE LIFT WILL OCCUR TO THE WEST OF THE REGION THROUGH THURSDAY. CONFIDENCE LOWERS BY FRIDAY AS TO HOW FAR EAST THE EJECTING MID LVL SYSTEM WILL TRACK DUE TO DOWNSTREAM UPPER RIDGE OVER MS RIVER VALLEY. WILL KEEP MAINLY DRY OVER ALL OF CWA THROUGH FRIDAY BEFORE ALLOWING POPS TO RENTER THE CWA FRIDAY NIGHT. TEMPS WILL RISE ABOVE CLIMO MOST OF THE WEEK. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1232 PM CDT SAT OCT 5 2013 IFR AND MVFR CIGS/VSBYS WILL PERSIST THROUGH TODAY AND MOST OF TONIGHT BEFORE GRADUAL IMPROVEMENT IS SEEN BY LATE SUNDAY MORNING ACROSS THE WRN TERMINALS. LIGHT SCATTERED RAIN SHOWERS ARE EXPECTED THIS AFTERNOON WITH MORE WIDESPREAD HEAVIER SHOWERS POSSIBLE THIS EVENING...AFTER 23/00Z...LASTING THROUGH 05/06Z. VSBYS WILL LOWER IN THE STRONGER SHOWERS...WITH POSSIBLY PATCHY FOG AROUND DLH AND HYR TONIGHT. GUSTY NE WINDS WILL SLOWLY DIMINISH IN INTENSITY AND BACK TO THE NORTH TONIGHT. && .PRELIMINARY POINT TEMPS/POPS... DLH 49 47 51 41 / 80 80 60 20 INL 47 39 54 38 / 70 50 40 10 BRD 54 46 53 40 / 80 80 60 20 HYR 57 44 59 41 / 80 80 50 30 ASX 55 49 57 44 / 80 80 60 40 && .DLH WATCHES/WARNINGS/ADVISORIES... MN...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR MNZ020-037. WI...WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR WIZ001-002. LS...GALE WARNING UNTIL 10 PM CDT THIS EVENING FOR LSZ141>147. SMALL CRAFT ADVISORY UNTIL 4 AM CDT SUNDAY FOR LSZ121-140-148. && $$ SHORT TERM...DAP LONG TERM...CANNON AVIATION...BJT
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1236 PM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 THE MSAS SHOWS THE SFC LOW NEARLY STATIONARY THIS MORNING ACROSS SCNTL SD. THE LOW IS IN THE PROCESS OF DOING A LOOP. THIS AFTERNOON IT WILL DRIFT EAST AT 5 MPH INTO SERN SD AND THIS IS CONSISTENT WITH THE MOTION OF THE 500 MB LOW AT JUST 6 KT. VERY SLOW STORM MOTIONS OF THIS TYPE...5 MPH...OFTEN PRODUCE HIGH WIND EVENTS IN THE CNTL PLAINS. THE GFS...ECM AND RAP SHOW SUSTAINED WINDS INCREASING TO AROUND 40 MPH ACROSS NCNTL NEB THIS AFTERNOON WITH GUSTS TO 58 MPH IN THE RAP AND HRRR MODELS. THE NAM KEEPS THE GUSTS BELOW 58 MPH THIS AFTN. MEANWHILE THE MET GUIDANCE SHOWS NO HIGH WIND EVENT AT ALL WHILE THE MAV GUIDANCE FAVORS SWRN NEB. THE MULTI LAYER WINDS IN THE RAP MODEL FROM H850MB TO H700MB KEEP WINDS AT 60 KTS OR LESS AND THIS IS CONSISTENT WITH A HIGH END WIND ADVISORY WITH A FEW GUSTS TO 58 MPH. THUS THERE IS A SPLIT IN THE MODEL DATA. A HIGH END WIND ADVISORY EVENT WOULD APPEAR TO BE THE MOST LIKELY SOLN INDICATED BY THE MODELS BUT LOCAL STUDIES SUGGEST A HIGH WIND EVENT WOULD UNFOLD THIS AFTERNOON. A WIND ADVISORY WILL CONTINUE TODAY ACROSS ALL AREAS EXCEPT WHERE THE WINTER STORM WARNING IS IN EFFECT. WINTER STORM CONDITIONS ARE LIKELY ONGOING ACROSS NRN SHERIDAN AND WRN CHERRY COUNTIES THIS MORNING. THE RADAR MAY BE OVERSHOOTING THE DENDRITIC LAYER. THE ELLSWORTH NEDOR CAM IS QUIET WHILE THE RUSHVILLE CAM CONTINUES TO SHOW SNOW AND BLOWING SNOW WITH VISIBILITY AROUND 2 MILES OR SO. THE 08Z KIEN OB SHOWS 1/2 MILE VISIBILITY WITH A VERTICAL VISIBILITY OF JUST 500 FEET. THE REST OF THE NEDOR CAMS ARE DARK SO WE WILL HAVE TO WAIT FOR SUNRISE TO GET A BETTER ANALYSIS OF THE SITUATION ACROSS NW NEB. THE WINTER STORM WARNING WILL CONTINUE UNTIL 18Z AS FORECAST. GIVEN THE UPPER LOW HAS STALLED ACROSS THE CNTL PLAINS...THE MODEL CONSENSUS SHOWS WRAPAROUND RAIN AND SNOW TODAY THROUGH SUNDAY MORNING. THE UPPER LEVEL LOW IS EXPECTED TO CONTINUE MOVING SLOWLY EAST SOUTHEAST INTO SRN IOWA BY LATE SUNDAY AFTERNOON. A MULTI MODEL CONSENSUS WAS USED FOR POPS TONIGHT AND SUNDAY. THE RAP MODEL WAS USED EXCLUSIVELY FOR THE TODAY PERIOD. NONE OF THE MODELS ARE SHOWING VERY HEAVY QPF AND SNOW TOTALS OF 2 INCHES OR LESS ARE EXPECTED BASED ON THAT OUTPUT. THERE IS SOME UNCERTAINTY WITH THIS FORECAST AS THE 850 MB MOISTURE TRANSPORT IS STILL QUITE STRONG ACROSS THE NRN PLAINS AND OCCASIONAL LIGHTNING STRIKES ARE STILL SHOWING UP AT 08Z. THE NAM WHICH APPEARS TO HAVE THE BEST HANDLE THE MASSIVE QPF ASSOCIATED WITH THIS STORM GENERALLY KEEPS QPF LESS THAN 0.10 INCHES IN ANY 3 HOUR PERIOD ACROSS NRN NEB. OTHERWISE...HIGHS TODAY RISE INTO THE 30S AND 40S ACCORDING TO A BLEND OF BIAS CORRECTED AND DETERMINISTIC DATA. THE MODELS ARE FORECASTING LOWS IN THE MID 20S TONIGHT ACROSS THE SNOW FIELD ACROSS NWRN NEB WITH LOWER 30S ELSEWHERE. IF THE WRN HALF OF THE FORECAST AREA CLEARS OUT TONIGHT AS INDICATED IN THE MODELS THEN THESE LOWS COULD BE 5 OR MORE DEGREES COLDER. HIGHS SUNDAY RISE INTO THE 40S ACROSS THE SNOW COVERED NORTHWEST WITH 50S AND 60S ELSEWHERE. .LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY) ISSUED AT 350 AM CDT SAT OCT 5 2013 BY SUNDAY NIGHT THE LOW PRESSURE SYSTEM WILL HAVE PUSHED TOWARDS THE MID MISS RVR VALLEY AND THE WRAP AROUND MOISTURE WILL HAVE SHIFTED INTO EASTERN NEB. MEANWHILE AN UPPER LEVEL RIDGE WILL BUILD ACROSS THE WEST...AS THE NEXT TROUGH PUSHES ACROSS NORTHEASTERN PACIFIC OCEAN. MONDAY THROUGH THURSDAY THE PACIFIC TROUGH WILL DIG TOWARDS THE DESERT SOUTHWEST WHILE THE UPPER RIDGE SHIFTS EAST ACROSS THE PLAINS. AT THE SFC HIGH PRESSURE WILL DOMINATE THE PLAINS THROUGH MUCH OF THE WEEK. THUS EXPECT MILD CONDITIONS WITH 70S AND A FEW MID/UPPER 60S ACROSS THE NW ZONES WHERE SOME INFLUENCE FROM THE HEAVY SNOW PACK IS LIKELY TO LIMIT THE HEATING. ONCE THE SNOW MELTS...COULD SEE MORE WIDESPREAD HIGHS INTO THE 70S ACROSS THE NW. WITH THE WARM AIR MASS...EXPECT SEASONALLY WARM LOWS...GENERALLY IN THE 40S SPOTTED WITH A FEW UPPER 30S. LATE THURSDAY INTO FRIDAY THE LOW OVER THE SW WILL BEGIN TO EJECT ONTO THE NORTHERN PLAINS. MODELS IN FAIR AGREEMENT...CONSIDERING 6/7 DAYS OUT...WITH A TRACK OF THE UPPER LOW ACROSS THE CENTRAL ROCKIES AND INTO S DAKOTA. THE MODELS CONTINUE TO TRACK THE LOW TO THE NE...INTO CANADA OVER THE WEEKEND. AS THE LOW PUSHES ONTO THE ROCKIES...GOOD MOISTURE TRANSPORT WITH S WINDS EXPECTED ACROSS THE AREA. POPS ARE NEEDED FOR THURSDAY INTO FRIDAY...HOWEVER PENDING THE TRACK AND THE DRY SLOT...CONCERNED AMOUNTS MAY NOT AMOUNT TO TOO MUCH OVER PART OF THE CWA. THUS WILL HOLD POPS IN THE SLIGHT CHANCE AND LOWER CHANCE CATEGORY. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1229 PM CDT SAT OCT 5 2013 STRONG LOW PRESSURE SYSTEM SLOWLY MOVING THROUGH THE NORTHERN PLAINS WILL CONTINUE TO IMPACT THE AVIATION FORECAST IN WESTERN AND NORTH CENTRAL NEBRASKA THROUGH SUNDAY MORNING. SNOW SQUALLS WILL MOVE THROUGH KVTN DURING THE AFTERNOON AND BRING VSBYS DOWN TO 2SM OR LESS AT TIMES. SNOW SHOWER ACTIVITY WILL BEGIN TO TAPER OFF THIS EVENING AND OVERNIGHT. NO SNOW SHOWERS ARE ANTICIPATED TO REACH KLBF...HOWEVER CIGS WILL HOVER AT OR JUST ABOVE MVFR LEVELS THROUGH THE AFTERNOON. GUSTY WINDS NORTHWEST WINDS WILL REMAIN THROUGH THE TAF PERIOD. STRONGEST WINDS GUSTING TO 35 TO 40 KTS ARE EXPECTED THIS AFTERNOON AND EARLY EVENING. WINDS WILL BEGIN TO RELAX AFTER 00Z WITH WIND GUSTS OF 20 TO 25 KTS EXPECTED BY SUNDAY MORNING. && .LBF WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NEZ006>010-022>029-035>038-056>059-069>071. WINTER WEATHER ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR NEZ004-005-094. && $$ SHORT TERM...CDC LONG TERM...MASEK AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
255 PM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN OVER THE REGION THROUGH TONIGHT THEN LIFT NORTH AS A WARM FRONT ON SUNDAY. THIS WILL KEEP OUR WEATHER UNSETTLED THROUGH THE WEEKEND WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS, PRIMARILY DURING THE DAYLIGHT HOURS. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 1155 AM UPDATE...CURRENT SFC ANALYSIS SHOWS STATIONARY FRONT SLIGHTLY FURTHER SOUTH THEN YESTERDAY. ATTM IT STRETCHES ACROSS THE SOUTHERN TIER OF NYS THEN DROPS SOUTHEAST INTO THE POCONOS. CONVECTION OVER THE NRN FINGER LAKES REGION HAS ALMOST DISSIPATED AS IT ENCOUNTERED A FAIRLY STABLE AIRMASS WELL NORTH OF THE BOUNDARY. SATELLITE SHOWS STRATUS BEGINNING TO MIX OUT OVER NE PA AND THE SOUTHERN TIER. THESE LOCATIONS WILL SEE SOME SUNNY BREAKS THIS AFTERNOON WITH THE WYOMING VALLEY LIKELY TO SEE THE MOST SUNSHINE. MODELS CONTINUE TO SUGGEST A WEAK SHORT WAVE WILL MOVE ALONG THE BOUNDARY LATER THIS AFTERNOON AND INTO THE EARLY EVENING. CURRENT POPS LOOK REASONABLE WITH ONLY MINOR ADJUSTMENTS. ISOLATED THUNDER IS STILL POSSIBLE LATER TODAY ALONG AND SOUTH OF THE SFC FEATURE. 915 AM UPDATE...LOCAL RADAR SHOWS A CLUSTER OF SHOWERS WITH EMBEDDED ISOLATED THUNDER MOVING INTO THE FINGER LAKES REGION. BASED ON CURRENT MOVEMENT AND HRRR OUTPUT THIS CLUSTER WILL MOVE ACROSS THE FINGER LAKES REGION AND INTO THE NRN CWA THROUGH LATE MORNING. INCREASED POPS IN THE ABOVE MENTIONED AREAS AND INCLUDED ISOLATED T EXCEPT FAR NRN CWA WHERE MODEL SOUNDINGS INDICATE NO INSTABILITY. REST OF FORECAST IN GOOD SHAPE. 620 AM UPDATE... TEMPS HV STAYED UP IN THE 60S UNDER EXTENSIVE STRATUS AND FOG DECK. EXPECT PATCHY DENSE FOG WL CONTINUE THRU 14Z ALONG WITH ISOLD SHOWERS WITH STATIONARY FRONT LURKING ACRS THE AREA. AREA OF SHOWERS MVG INTO NIAGARA FRONTIER AHD OF S/WV MAY MV INTO WRN CNTYS TWD 12Z. KEPT SLGT CHC POPS IN ALL NIGHT FOR CNTRL CNTYS AND EXPECT POPS TO INCRS IN CVRG ACRS TWIN TIERS TWD LATE MRNG. THUS NO CHGS NEEDED AT THIS TIME OTHER THAN T/TD GRIDS TO COME MORE INTO LINE WITH REALITY. PREV DISCUSSION BLO... 330 AM UPDATE... WMFNT IS CURRENTLY STRETCHED FM SFC LOW NR PIERRE SD ALONG THE I-90 CORRIDOR TO BTWN KBUF AND KERI AND ALONG NY/PA BORDER. DO NOT EXPECT MUCH IN THE WAY OF MVMNT TDA AS 1028MB HIPRES RMNS LOCKED ACRS ERN CANADA AND CLOSED LOW JUST CREEPS ALONG, ROUGHLY 100 MILES IN 12 HRS, AS IT WAITS FOR AN UPSTREAM KICKER. AS FOR TDA`S FCST EXPECT ISOLD/SCTD CONVECTION AS WMFNT RMNS OVR AREA. ISOLD SHOWERS EXPECTED UNTIL ABOUT NOON TDA AS ANY EMBEDDED S/WVS MAY KICK SOMETHING OFF WITH FRONTAL BNDRY IN AREA. HWVR AFT ABOUT 16Z INSTABILITY LOOKS TO NOSE INTO REGION MAINLY ALONG BNDRY WITH CAPES BTWN 200-400 J/KG AND K-INDICES APPCHG 35. EXPECT CONVECTION AFT THIS TIME ACRS THE SRN TIER/SUSQ REGION, THEN SOUTH INTO NEPA AFT 18Z. NRN CNTYS EXPECTED TO BE SOCKED IN WITH LOCLDS ALL DAY NORTH OF THE BNDRY SIMILAR TO YDA. THUS HV NOT ADDED ANY THUNDER INTO ZONES ALONG AND NORTH OF THE NY THRUWAY AT THIS TIME. SKIES EXPECTED TO RMN CLDY ACRS NRN AREAS WITH SOME SUN POSSIBLY BREAKING OUT BRIEFLY ACRS THE SOUTH. EXPECT AFTN MAXES SIMILAR TO YDA WITH HIGHS ARND 80 ACRS WRN AND SRN ZONES AND ONLY INTO THE 60S OVR NE CNTYS. FNT WL BEGIN LIFTING NORTH SAT NGT AS HIPRES BUILDS INTO THE CANADIAN MARITIMES AND SRLY WINDS INCRS. EXPECT SLGT/CHC SHOWERS THRU THE OVRNGT ACRS CWA, INCRSG TO LKLY TWD SUN MRNG ACRS NRN ZONES AS EJECTING WV FM UPSTREAM CLOSED LOW RIDES ALONG FRONTAL BNDRY AND INITIATES CONVECTION. OVRNGT LOWS FOR SUN MRNG WL LKLY RMN ARND NRML VALUES (L/M 60S) FOR HIGHS THIS TIME OF YR, NOT EVEN CLOSE TO NORMAL LOWS. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... 330 AM UPDATE... CWA WL BE IN WM SECTOR ON SUNDAY WITH SCTD CONVECTION EXPECTED OFF AND ON THROUGHOUT THE DAY AS ANY SUBTLE WVS THAT CAN MV THRU WL GENERATE CHCS FOR SHRA/TSRA. FOR NOW, HV NOT MADE MANY CHGS DUE TO UNSETTLED PATTERN AND DIFFICULTY RESOLVING ANY TRIGGERS. AREA RMNS IN WARM SECTOR ON SUN NGT AND CAN EXPECT JUST CHC SHOWERS THRU 12Z MON SO HV DROPPED POPS TO JUST 30% AT THIS TIME FOR THE PD. WARM AND HUMID CONDS WL CONT THRU MON MRNG WITH TEMPS AND TDS IN THE U50S/L60S. MOISTURE FM TROPICAL STORM KAREN PROGGED BY GFS TO WORK UP INTO AREA MON NGT. HWVR, THIS WL ALL DEPEND ON HOW MUCH H5 SYSTEM SLOWS DOWN AND IF FRONTAL BNDRY CAN HOLD OFF ENUF TO BRING MOISTURE INTO AREA. AS OF NOW WITH PW VALUES INCRSG TO BTWN 1.5 AND 1.75 INCHES ON MON NGT EXPECTED 12-HR QPF VALUES FM HPC WL AVG ARND 1 INCH THRU THE END OF THE SHORT TERM. FROPA LOOKS TO HV SLOWED DOWN ENUF TO OCCUR AT THE VRY TAIL END OF THE SHORT TERM. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... 240 PM EDT UPDATE... A MUCH DRIER WEATHER PATTERN IS EXPECTED IN THE EXTENDED THAN IN THE NEAR TERM. THE UPPR LVL TROUGH THAT WILL BRING SHOWERS AND THUNDERSTORMS OVER THE NEXT COUPLE OF DAYS WILL PUSH OUT OF THE AREA TUESDAY/TUESDAY NIGHT. IN ITS WAKE AN UPPER AND LOWER LVL RIDGE WILL BUILD INTO THE REGION. THERE WILL STILL BE A SLIGHT CHANCE FOR SHOWERS ON TUESDAY/TUESDAY NIGHT FROM LINGERING MOISTURE OF KAREN BUT WILL DIMINISH QUICKLY THEREAFTER. WENT CLOSELY WITH WPC GUIDANCE AND KEPT THE FORECAST DRY AS CHANCES FOR RAIN ARE VERY MINIMAL THROUGH THE EXTENDED. HIGH TEMPS STARTING WED THROUGH SAT WILL BE MUCH COOLER AS WELL... WITH HIGHS REMAINING IN THE MID TO UPPER 60S EVEN THOUGH CLOUD COVERAGE WILL BE FOR THE MOST PART PARTLY CLOUDY. THESE TEMPS WILL BE CLOSER TO THE SEASONABLE NORM BUT ARE STILL ABOVE AVERAGE. COOLER TEMPS ARE AHEAD. & .AVIATION /19Z SATURDAY THROUGH THURSDAY/... 140 PM EDT UPDATE... A VERY CHALLENGING FORECAST IS IN STORE FOR THE NEXT 24 HOURS AS A WARM FRONT LIFTS NORTH FROM THE BORDER OF PA TO NORTHERN NY. CURRENTLY ACROSS THE REGION A VERY DENSE MVFR STRATUS DECKS LIES ACROSS MUCH OF CENTRAL NY. DUE TO HEATING FROM THE SUN...WE DO EXPECT THESE CLOUDS TO LIFT BRIEFLY TO VFR THIS AFTERNOON/EVENING. CONFIDENCE IS NOT HIGH ON THE TIMING OF THE TRANSITION. THERE IS A CHANCE FOR LIGHT RAIN SHOWERS THIS AFTERNOON...BUT WITHOUT STRONG UPPER FORCING DECIDED TO KEEP OUT OF TAFS DUE TO UNCERTAINTY OF LOCATION. THE OVERALL CHANCE FOR RAIN SHOWERS WILL INCREASE AFTER 00Z TONIGHT AS THE DRAPED WARM FRONT MOVES NORTH. THE BEST CHANCES FOR RAIN ARE AT KRME... KITH... AND KSYR. THESE SHOWERS MAY PERSIST WELL INTO THE AFTERNOON ON SUNDAY AND EXPECT THESE SHOWERS TO BE FUEL ALTERNATE CIGS AND VISBYS. OUTLOOK... SUNDAY THROUGH THURSDAY...AN UNSETTLED PERIOD...WITH SCATTERED TO WIDESPREAD SHOWERS ANTICIPATED...ALG WITH THE LIKELIHOOD OF RESTRICTIVE CONDS FROM TIME TO TIME. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM...KAH AVIATION...KAH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
158 PM EDT SAT OCT 5 2013 .SYNOPSIS... A STATIONARY FRONT WILL REMAIN OVER THE REGION THROUGH TONIGHT THEN LIFT NORTH AS A WARM FRONT ON SUNDAY. THIS WILL KEEP OUR WEATHER UNSETTLED THROUGH THE WEEKEND WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS, PRIMARILY DURING THE DAYLIGHT HOURS. && .NEAR TERM /THROUGH TONIGHT/... 1155 AM UPDATE...CURRENT SFC ANALYSIS SHOWS STATIONARY FRONT SLIGHTLY FURTHER SOUTH THEN YESTERDAY. ATTM IT STRETCHES ACROSS THE SOUTHERN TIER OF NYS THEN DROPS SOUTHEAST INTO THE POCONOS. CONVECTION OVER THE NRN FINGER LAKES REGION HAS ALMOST DISSIPATED AS IT ENCOUNTERED A FAIRLY STABLE AIRMASS WELL NORTH OF THE BOUNDARY. SATELLITE SHOWS STRATUS BEGINNING TO MIX OUT OVER NE PA AND THE SOUTHERN TIER. THESE LOCATIONS WILL SEE SOME SUNNY BREAKS THIS AFTERNOON WITH THE WYOMING VALLEY LIKELY TO SEE THE MOST SUNSHINE. MODELS CONTINUE TO SUGGEST A WEAK SHORT WAVE WILL MOVE ALONG THE BOUNDARY LATER THIS AFTERNOON AND INTO THE EARLY EVENING. CURRENT POPS LOOK REASONABLE WITH ONLY MINOR ADJUSTMENTS. ISOLATED THUNDER IS STILL POSSIBLE LATER TODAY ALONG AND SOUTH OF THE SFC FEATURE. 915 AM UPDATE...LOCAL RADAR SHOWS A CLUSTER OF SHOWERS WITH EMBEDDED ISOLATED THUNDER MOVING INTO THE FINGER LAKES REGION. BASED ON CURRENT MOVEMENT AND HRRR OUTPUT THIS CLUSTER WILL MOVE ACROSS THE FINGER LAKES REGION AND INTO THE NRN CWA THROUGH LATE MORNING. INCREASED POPS IN THE ABOVE MENTIONED AREAS AND INCLUDED ISOLATED T EXCEPT FAR NRN CWA WHERE MODEL SOUNDINGS INDICATE NO INSTABILITY. REST OF FORECAST IN GOOD SHAPE. 620 AM UPDATE... TEMPS HV STAYED UP IN THE 60S UNDER EXTENSIVE STRATUS AND FOG DECK. EXPECT PATCHY DENSE FOG WL CONTINUE THRU 14Z ALONG WITH ISOLD SHOWERS WITH STATIONARY FRONT LURKING ACRS THE AREA. AREA OF SHOWERS MVG INTO NIAGARA FRONTIER AHD OF S/WV MAY MV INTO WRN CNTYS TWD 12Z. KEPT SLGT CHC POPS IN ALL NIGHT FOR CNTRL CNTYS AND EXPECT POPS TO INCRS IN CVRG ACRS TWIN TIERS TWD LATE MRNG. THUS NO CHGS NEEDED AT THIS TIME OTHER THAN T/TD GRIDS TO COME MORE INTO LINE WITH REALITY. PREV DISCUSSION BLO... 330 AM UPDATE... WMFNT IS CURRENTLY STRETCHED FM SFC LOW NR PIERRE SD ALONG THE I-90 CORRIDOR TO BTWN KBUF AND KERI AND ALONG NY/PA BORDER. DO NOT EXPECT MUCH IN THE WAY OF MVMNT TDA AS 1028MB HIPRES RMNS LOCKED ACRS ERN CANADA AND CLOSED LOW JUST CREEPS ALONG, ROUGHLY 100 MILES IN 12 HRS, AS IT WAITS FOR AN UPSTREAM KICKER. AS FOR TDA`S FCST EXPECT ISOLD/SCTD CONVECTION AS WMFNT RMNS OVR AREA. ISOLD SHOWERS EXPECTED UNTIL ABOUT NOON TDA AS ANY EMBEDDED S/WVS MAY KICK SOMETHING OFF WITH FRONTAL BNDRY IN AREA. HWVR AFT ABOUT 16Z INSTABILITY LOOKS TO NOSE INTO REGION MAINLY ALONG BNDRY WITH CAPES BTWN 200-400 J/KG AND K-INDICES APPCHG 35. EXPECT CONVECTION AFT THIS TIME ACRS THE SRN TIER/SUSQ REGION, THEN SOUTH INTO NEPA AFT 18Z. NRN CNTYS EXPECTED TO BE SOCKED IN WITH LOCLDS ALL DAY NORTH OF THE BNDRY SIMILAR TO YDA. THUS HV NOT ADDED ANY THUNDER INTO ZONES ALONG AND NORTH OF THE NY THRUWAY AT THIS TIME. SKIES EXPECTED TO RMN CLDY ACRS NRN AREAS WITH SOME SUN POSSIBLY BREAKING OUT BRIEFLY ACRS THE SOUTH. EXPECT AFTN MAXES SIMILAR TO YDA WITH HIGHS ARND 80 ACRS WRN AND SRN ZONES AND ONLY INTO THE 60S OVR NE CNTYS. FNT WL BEGIN LIFTING NORTH SAT NGT AS HIPRES BUILDS INTO THE CANADIAN MARITIMES AND SRLY WINDS INCRS. EXPECT SLGT/CHC SHOWERS THRU THE OVRNGT ACRS CWA, INCRSG TO LKLY TWD SUN MRNG ACRS NRN ZONES AS EJECTING WV FM UPSTREAM CLOSED LOW RIDES ALONG FRONTAL BNDRY AND INITIATES CONVECTION. OVRNGT LOWS FOR SUN MRNG WL LKLY RMN ARND NRML VALUES (L/M 60S) FOR HIGHS THIS TIME OF YR, NOT EVEN CLOSE TO NORMAL LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... 330 AM UPDATE... CWA WL BE IN WM SECTOR ON SUNDAY WITH SCTD CONVECTION EXPECTED OFF AND ON THROUGHOUT THE DAY AS ANY SUBTLE WVS THAT CAN MV THRU WL GENERATE CHCS FOR SHRA/TSRA. FOR NOW, HV NOT MADE MANY CHGS DUE TO UNSETTLED PATTERN AND DIFFICULTY RESOLVING ANY TRIGGERS. AREA RMNS IN WARM SECTOR ON SUN NGT AND CAN EXPECT JUST CHC SHOWERS THRU 12Z MON SO HV DROPPED POPS TO JUST 30% AT THIS TIME FOR THE PD. WARM AND HUMID CONDS WL CONT THRU MON MRNG WITH TEMPS AND TDS IN THE U50S/L60S. MOISTURE FM TROPICAL STORM KAREN PROGGED BY GFS TO WORK UP INTO AREA MON NGT. HWVR, THIS WL ALL DEPEND ON HOW MUCH H5 SYSTEM SLOWS DOWN AND IF FRONTAL BNDRY CAN HOLD OFF ENUF TO BRING MOISTURE INTO AREA. AS OF NOW WITH PW VALUES INCRSG TO BTWN 1.5 AND 1.75 INCHES ON MON NGT EXPECTED 12-HR QPF VALUES FM HPC WL AVG ARND 1 INCH THRU THE END OF THE SHORT TERM. FROPA LOOKS TO HV SLOWED DOWN ENUF TO OCCUR AT THE VRY TAIL END OF THE SHORT TERM. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 345 AM UPDATE... MED RNG GRIDS UPDATED WITH 00Z WPC GDNC (BLENDED WITH SOME GFS/MOS DATA) TO REFLECT A SLOWER MVMNT OF THE UPR LOW...WITH AN EXTENSION OF CHC POPS INTO MID WEEK AND MORE IN THE WAY OF CLDS DUE TO THIS SYSTEM. PREV BLO... 2 PM UPDATE... MAIN INTEREST IN THE LONG TERM FORECAST WILL BE THE POTENTIAL FOR HEAVY RAIN MONDAY NIGHT. THE MAIN WEATHER PLAYERS WILL BE AN UPPER LEVEL LOW NOW OVER SE WYOMING...AND ASSOCIATED COLD FRONT OVER THE CENTRAL PLAINS. AS THESE FEATURES MOVE EAST THE SOUTHERLY FLOW OF AIR AHEAD OF THEM WILL TRANSPORT MOISTURE...SOME OF IT WILL BE WHATS LEFT OF TS KAREN...NORTHWARD INTO OUR AREA. WITH HIGH VARIANCE IN THE MODELS JUST 24 HOURS AGO...THE 12Z NAM AND GFS ARE FAIRLY SIMILAR IN SHOWING AN AREA OF STEADY RAIN ALONG AND AHEAD OF THE COLD FRONT MOVING INTO OUR AREA MONDAY EVENING. BOTH THE GFS AND WPC GUIDANCE SHOW A GENERAL 1" TO 2" RAIN ACROSS THE AREA MONDAY NIGHT...WITH ISOLATED HIGHER AMOUNTS POSSIBLE. WITH OUR RECENT STRETCH OF DRY WEATHER AND THE PROGRESSIVE NATURE OF THE FRONT (RAIN FALLING IN 12 HOURS OR LESS)...WIDESPREAD PROBLEMS ARE NOT EXPECTED AT THIS EARLY JUNCTURE. IN FACT FOR MOST THIS WILL BE A WELCOME BENEFICIAL FALL RAIN. LATER TUESDAY AND BEYOND...THE GFS IS NOW THE SLOWEST WITH THE UPPER LEVEL LOW MOVING OVER OUR AREA AND KEEPING US CLOUDY/UNSETTLED FOR ONE MORE DAY. WILL LEAN WITH WPC GUIDANCE DRYING US OUT BY TUESDAY NIGHT. HIGH PRESSURE CONTROLS THE REST OF THE PERIOD WITH QUIET WEATHER EXPECTED. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... 140 PM EDT UPDATE... A VERY CHALLENGING FORECAST IS IN STORE FOR THE NEXT 24 HOURS AS A WARM FRONT LIFTS NORTH FROM THE BORDER OF PA TO NORTHERN NY. CURRENTLY ACROSS THE REGION A VERY DENSE MVFR STRATUS DECKS LIES ACROSS MUCH OF CENTRAL NY. DUE TO HEATING FROM THE SUN...WE DO EXPECT THESE CLOUDS TO LIFT BRIEFLY TO VFR THIS AFTERNOON/EVENING. CONFIDENCE IS NOT HIGH ON THE TIMING OF THE TRANSITION. THERE IS A CHANCE FOR LIGHT RAIN SHOWERS THIS AFTERNOON...BUT WITHOUT STRONG UPPER FORCING DECIDED TO KEEP OUT OF TAFS DUE TO UNCERTAINTY OF LOCATION. THE OVERALL CHANCE FOR RAIN SHOWERS WILL INCREASE AFTER 00Z TONIGHT AS THE DRAPED WARM FRONT MOVES NORTH. THE BEST CHANCES FOR RAIN ARE AT KRME... KITH... AND KSYR. THESE SHOWERS MAY PERSIST WELL INTO THE AFTERNOON ON SUNDAY AND EXPECT THESE SHOWERS TO BE FUEL ALTERNATE CIGS AND VISBYS. OUTLOOK... SUNDAY THROUGH THURSDAY...AN UNSETTLED PERIOD...WITH SCATTERED TO WIDESPREAD SHOWERS ANTICIPATED...ALG WITH THE LIKELIHOOD OF RESTRICTIVE CONDS FROM TIME TO TIME. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...NONE. NY...NONE. && $$ SYNOPSIS...PVN NEAR TERM...PVN/RRM SHORT TERM...PVN LONG TERM... AVIATION...KAH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
155 PM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE OVER THE REGION WILL MOVE SLOWLY EAST AND OFF SHORE OF THE CAROLINA COAST TONIGHT AND SUNDAY. WEAK LOW PRESSURE...AND MOISTURE STREAMING AWAY FROM KAREN...WILL MOVE NORTHEAST ALONG A COLD FRONT THAT WILL CROSS THE CAROLINAS ON MONDAY. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1000 AM SATURDAY... SURFACE RIDGE REMAINS IN PLACE OVER CENTRAL NORTH CAROLINA...AND THE MORNING UPPER-AIR ANALYSIS SHOWED THE RIDGE AXIS ALOFT JUST TO OUR WEST. MORNING AMDAR SOUNDINGS AS WELL AS THE SOUNDING FROM KGSO NOTED WARMING ALOFT AROUND 600MB OVER THE LAST 24 HOURS... REPRESENTING STRONG CAPPING. THE LATEST RAP SHOWS THE RIDGE ALOFT BUILDING EAST OVERHEAD DURING THE AFTERNOON...WITH GOOD SUBSIDENCE AND LITTLE OR NO MIXED-LAYER CAPE IN THE LOWEST KM. MORNING SOUNDINGS AND THE KRAX VAD WIND PROFILE NOTED A FAIRLY DEEP...BUT LIGHT...NORTHERLY COMPONENT TO THE WIND WHICH SHOULD VEER DURING THE DAY BASED ON THE LATEST RAP AND MOS GUIDANCE. MAIN CHANGES...ALL MINOR...TO THE FORECAST FOR THE AFTERNOON WERE TO MODIFY THE DIRECTION OF THE LIGHT WIND INTO THE MID-AFTERNOON HOURS...AND NOTE JUST A FEW MORE CLOUDS WITH SOME MOSTLY THIN CIRRUS WORKING ITS WAY EAST OF THE RIDGE AXIS ALOFT. 1000-850MB THICKNESSES FROM THE KGSO 12Z SOUNDING COMBINED WITH THE FORECAST MAXIMUM VALUE OF THAT PARAMETER THIS AFTERNOON GIVES MAXES IN LINE WITH THE FORECAST. LOWS TONIGHT WILL BE SIMILAR TO THIS MORNING...IN THE LOWER/MID 60S...COOLEST IN RURAL AND LOW-LYING AREAS. EXPECT AREAS OF FOG AGAIN TONIGHT UNDER A MAINLY CLEAR SKY...LIGHT WIND...AND SURFACE DEW POINTS LATE AT NIGHT 60 TO 65. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... AS OF 345 AM SATURDAY... AN IMPRESSIVE UPPER LEVEL LOW CENTERED OVER THE UPPER MIDWEST THIS MORNING WILL TRACK INTO THE CENTRAL MS RIVER VALLEY SUN INTO SUN NIGHT...WHILE ADDITIONAL SHORTWAVE ENERGY (OVER THE 4-CORNERS REGION THIS MORNING) DIGS SOUTHEAST THROUGH THE LOWER MIDWEST INTO THE LOWER MS RIVER VALLEY ALONG THE SOUTHERN PERIPHERY OF THE UPPER LOW. ADDITIONALLY...TROPICAL CYCLONE KAREN IS EXPECTED TO TRACK SLOWLY NORTH TOWARD THE GULF COAST ON SUN...MOVING ASHORE SOMEWHERE IN THE DEEP SOUTH SUN NIGHT. IN THE LOWER LEVELS...A COLD FRONT ASSOC/W AN OCCLUDED SFC LOW ATTENDANT THE UPPER LEVEL LOW WILL TRACK EAST INTO THE TN/OH VALLEY ON SUN...APPROACHING THE SOUTHERN APPALACHIANS SUN NIGHT. PER THE 00Z GUIDANCE...SOUTHERLY RETURN FLOW AND LOW-LEVEL WARM ADVECTION WILL NOT SIGNIFICANTLY STRENGTHEN UNTIL SUN NIGHT...AND THE AIRMASS ON SUNDAY IS EXPECTED TO BE VERY SIMILAR TO TODAY WITH A PRONOUNCED MID-LEVEL CAP AND MEAGER DIURNAL DESTABILIZATION (AT BEST). FORCING FOR ASCENT WILL LARGELY BE ABSENT OVER CENTRAL NC...CONFINED TO THE SEABREEZE OVER THE COASTAL CAROLINAS AND SMALL AMPLITUDE DISTURBANCES IN STRENGTHENING SW FLOW ALOFT OVER FAR WESTERN PORTIONS OF THE STATE DURING THE AFT/EVE. AS A RESULT...WILL CONTINUE TO INDICATE A DRY FCST ON SUN. A RAPID INCREASE IN LOW-LEVEL MOISTURE ASSOC/W STRENGTHENING SOUTHERLY FLOW WILL OCCUR SUN NIGHT AND MON MORNING...WITH ASCENT INCREASING IN THE FORM OF LOW-LEVEL WARM ADVECTION AND DPVA ASSOC/W SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT. ALL OF THE 00Z GUIDANCE INDICATES MEASURABLE PRECIP IN THE WESTERN PIEDMONT BY 12Z MON...AND THIS SEEMS CONSISTENT WITH THE AFOREMENTIONED DISCUSSION. WILL INDICATE PRECIP CHANCES INCREASING FROM THE WEST AFTER MIDNIGHT...RANGING FROM 60-80% IN THE FAR WESTERN PIEDMONT TO ~20% ALONG THE I-95 CORRIDOR. EAST OF I-95...FORCING FOR ASCENT WILL BE MUCH WEAKER AND PRECIP CHANCES WILL LARGELY BE TIED TO SHOWER ACTIVITY MOVING INLAND FROM THE ATLANTIC IN ASSOC/W ONSHORE FLOW. AS A RESULT...WILL INDICATE A DRY FCST IN THE FAR NE COASTAL PLAIN WITH A SLIGHT CHANCE SOUTH OF HWY 64 IN THE SE COASTAL PLAIN. THICKNESSES WILL BE SLIGHTLY LOWER (PERHAPS 5-10M) THAN TODAY. THIS...ALONG WITH INCREASING CLOUD COVER DURING THE AFTERNOON SHOULD RESULT IN HIGHS A FEW DEGREES COOLER THAN TODAY IN THE MID 80S (84-88F)...COOLEST IN THE WESTERN PIEDMONT. LOWS SUN NIGHT WILL BE TEMPERED BY CLOUD COVER AND A LIGHT SOUTHERLY BREEZE...IN THE UPPER 60S TO NEAR 70F IN THE SOUTH. -VINCENT && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 300 AM SATURDAY... THE LATEST INFORMATION FROM THE NHC CONCERNING "KAREN" CONTINUES TO DOWNGRADE THE TROPICAL SYSTEM. IT HAS BEEN DESCRIBED AS ALREADY BEING `DECAPITATED" BY ONE FORECASTER - DUE TO STRONGER WINDS ALOFT. THEREFORE... THE CONFIDENCE OF WHETHER ANY REMNANTS OF `KAREN" WILL BE LEFT TO BRING INDIRECT IMPACTS (RAIN, SEVERE THREAT) FOR CENTRAL NC BY EARLY NEXT WEEK HAS LOWERED. ON A MORE CONFIDENT NOTE... A MID/UPPER LEVEL TROUGH IS FORECAST TO BE APPROACHING THE APPALACHIANS MONDAY... THEN SWING ACROSS OUR REGION TUE AND TUE NIGHT. THE MAIN UPPER DYNAMICS ARE FORECAST TO PUSH FROM THE MIDWEST TO THE GREAT LAKES. HOWEVER... MOISTURE IS EXPECTED TO SURGE NORTHWARD ALONG THE EASTERN SEABOARD BRINGING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS ALONG THE COLD FRONT. IF THE REMNANT LOW PRESSURE OF `KAREN` TRACKS NE INTO NC AS SOME OF THE MODELS STILL SUGGEST... THERE CAN STILL BE ENHANCED RAINFALL FOR 12-24 HOURS. OTHERWISE... THIS WOULD BE A TYPICAL RAINFALL EVENT ASSOCIATED WITH A MID-LATITUDE TROUGH EARLY NEXT WEEK. ONCE THE TROUGH PASSES... CLEARING AND COOLER CONDITIONS ARE EXPECTED MID THROUGH LATE WEEK. LOWS 50-55. HIGHS 70-75. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... AS OF 155 PM SATURDAY... THE 18Z VALID TAF FORECAST WILL BASICALLY BE PERSISTENCE...WITH SOME AFTERNOON CU DIMINISHING LEAVING A FEW CIRRUS STREAMING ATOP THE RIDGE AXIS. LIGHT WINDS...MOSTLY LIGHT SOUTH...WITH DEW POINTS IN THE LOWER TO MID 60S LATE TONIGHT SHOULD RESULT IN AREAS OF FOG ONCE AGAIN. THE HIGHEST PROBABILITIES OF FOG CONTINUE TO BE TOWARD KFAY AND KRWI...LESSER TOWARD THE NORTHWEST. THE TAFS NOTE LOCAL MVFR VISIBILITY TOWARD KGSO AND KINT...LOCAL IFR VISIBILITY AT KRDU...AND RELATIVELY LOWER VISIBILITIES AT KFAY AND KRWI LATE TONIGHT INTO EARLY SUNDAY. WITH MIXING SUNDAY MORNING...A MORE NOTICEABLE SOUTHERLY WIND SHOULD DEVELOP WITH SURFACE SPEEDS AVERAGING JUST UNDER 10KT BY THE END OF THE 18Z VALID TAF PERIOD. BEYOND THE 18Z VALID TAF PERIOD...VFR CONDITIONS PERSIST UNTIL JUST AFTER MIDNIGHT SUNDAY NIGHT INTO MONDAY MORNING. MOISTURE STREAMING NORTH INTO THE CAROLINAS FROM THE GULF AHEAD OF A COLD FRONT LIKELY RESULTS IN CONDITIONS BECOMING SUB-VFR WITH AT LEAST NUMEROUS SHOWERS DEVELOPING. SOUTH WINDS SUNDAY NIGHT INCREASE ALOFT TO 30KT BY 2000FT AS THE SURFACE GRADIENT INCREASES AHEAD OF THE FRONT. BY TUESDAY...AVIATION CONDITIONS ARE EXPECTED TO IMPROVE TO PREDOMINANTLY VFR IN NORTHEAST FLOW BEHIND THE FRONT. THESE CONDITIONS CONTINUE THROUGH THURSDAY...WITH ONLY A SMALL PROBABILITY OF LOW CLOUDS IN A LOW-LEVEL NORTHEAST FLOW LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...SEC/DJF NEAR TERM...DJF/VINCENT SHORT TERM...VINCENT LONG TERM...BADGETT AVIATION...DJF
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
146 PM EDT SAT OCT 5 2013 .SYNOPSIS... SOUTHWEST FLOW OF WARM...MUGGY AIR CONTINUES INTO SUNDAY. COLD FRONT BRINGS SHOWERS ALONG WITH SOME STORMS LATE SUNDAY INTO MONDAY. UPPER LOW PULLS OUT MIDWEEK...YIELDING TO HIGH PRESSURE LATE WEEK. && .NEAR TERM /THROUGH TONIGHT/... UPDATE... A FEW SMALL WAVES EMBEDDED WITHIN THE UPPER RIDGE HAVE SPARKED SOME CONVECTION OVER THE OHIO VALLEY THIS MORNING...BUT THIS IS NOT ABLE TO GET MUCH IN TERMS OF VERTICAL EXTENT. HAD TO DRAG THE POPS A LITTLE FURTHER TO THE SOUTHEAST...BUT LEFT THEM OUT OF CRW. WILL REASSESS WHEN THE NEW MODELS ARE IN. HRRR HAS BEEN VALUABLE THIS MORNING. PREVIOUS DISCUSSION... SUMMER REPRISE CONTINUES. ALTOCU THIS MORNING AIDS IN ERADICATING THE DENSE VALLEY FOG OF EARLY MORNING...OR HOLDS IT IN IF IT SURVIVES DAWN....AND CU THIS AFTERNOON IN VERY WARM AND HUMID SW FLOW AS UPPER RIDGE MOVES E ACROSS AREA. WEAK RIPPLES IN THE UPPER LEVEL SW FLOW ONCE THE RIDGE GOES BY COULD GRAZE NW PORTION OF AREA WITH CONVECTION MIDDAY TODAY INTO THIS EVENING. FLOW GOES MORE SOUTHERLY TONIGHT...SO CONVECTION ASSOCIATED WITH RIPPLES IN FLOW WILL SHIFT N OF THE AREA WHILE THAT ASSOCIATED WITH COLD FRONT TO THE W REMAINS W OF THE AREA THROUGH 12Z SUN. ALTOCU LIMITED TO THE W. BOUNDARY LATER FLOW SHOULD PRECLUDE DENSE VALLEY FOG SAVE FOR THE DEEPER VALLEYS OF EASTERN WV LATE TONIGHT. ROLLED WITH BIAS CORRECTED ADJMET AND BIAS CORRECTED ALL BLEND TOGETHER WITH PREVIOUS FOR HIGHS TODAY WITH ADJMAV BEING TOO HIGH. LOWER TO MID 80S LOWLANDS IS 5-10F BELOW RECORD HIGHS. DID BLEND IN BIAS CORRECTED ADJMAV FOR LOWS TONIGHT...A TICK OR SO HIGHER THAN PREVIOUS ON RIDGE/HILL TOPS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... UNSETTLED WEATHER IN THE SHORT TERM PERIOD. RATHER WARM AND HUMID DAY ON TAP SUNDAY...AS UPPER LOW ACROSS CENTRAL U.S. DIGS SOUTH AND EAST...CAUSING FLOW TO BACK...AND SLOWING THE PROGRESSION OF THE COLD FRONT AND ASSOCIATED PRECIPITATION INTO THE CWA. STILL EXPECTING SOME DECENT RAINFALL TOTALS...AS LLJ AIDS IN MOISTURE TRANSPORT TO THE REGION...WITH PW VALUES EXPECTED TO RISE TO 1.6 TO 1.7 INCHES. AS WITH PREVIOUS FORECASTER...WILL LEAVE A MENTION OF WATER PROBLEMS OUT OF THE HWO DUE TO RECENT DRY SPELL...AND OVERALL PROGRESSIVE NATURE OF THE SYSTEM. IN ADDITION...AT THIS POINT...SPC HAS ISSUED ONLY A SEE TEXT AREA FOR THE CWA...AS CLOUD COVER...AND OVERALL LACK OF INSTABILITY SHOULD HOPEFULLY LIMIT THE SEVERE POTENTIAL ACROSS THE REGION. STILL...EXPECTING SOME RATHER GUSTY CONDITIONS ASSOCIATED WITH FRONTAL PASSAGE...SET TO TAKE PLACE ON MONDAY...PARTICULARLY ACROSS HIGHER ELEVATIONS. HOWEVER...THIS WILL NEED TO BE MONITORED AS MODELS ARE INDICATING STRONG FORCING WITH THE FRONT. MODELS CONTINUE TO INDICATE THAT REMNANTS OF KAREN WILL REMAIN FAR ENOUGH TO THE EAST OF THE AREA...THAT THE CWA WILL SEE LITTLE TO NO EFFECT. && .LONG TERM /TUESDAY THROUGH SATURDAY/... LOOKING AT UPR RIDGE TO BUILD ACROSS EASTERN CONUS IN THE EXTENDED WITH STALLED SFC FRONT LINGERING ALONG E COAST. SEASONABLE TEMPS DURING THE DAY AND COOL NIGHTS ON TAP. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... CONVECTION EXPECTED OVER THE OHIO VALLEY AGAIN TODAY...WITH ISOLATED CHANCES IN THE MOUNTAINS. ONLY HAVE VCTS IN THE PKB AREA GIVEN THE CURRENT SET OF POP GRIDS IN PLACE...WHERE THESE VALUES ARE THE HIGHEST. A FEW SHOWERS MAY LINGER AROUND HTS AS WELL...BUT THE BULK OF THE ACTIVITY SHOULD REMAIN CLOSER TO ILN/CMH/ZZV. DID NOT GO WITH MUCH FOG TONIGHT AS RH PROGS HAVE DEPTH OF THE MOISTURE EXTENDING THROUGH 550MB...ALLUDING TO CLOUD COVER IN PLACE. EKN MAY GET LIFR LATE TONIGHT WHERE THE CLOUD COVER IS NOT EXPECTED TO BE AS PROMINENT. WITH THE FRONTAL SYSTEM GETTING CLOSER...WILL SEE SURFACE FLOW AROUND 10KTS OUT OF THE SOUTHWEST SUNDAY. AIR FLOW OFF THE SURFACE WILL BE HIGHER WITH THE APPROACH OF THE LOW LEVEL JET. TRI STATE/SOUTHEAST OHIO LOCATIONS COULD SEE 40-50KTS OFF THE SURFACE AT AROUND 5KFT...ALSO OUT OF THE SOUTHWEST. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY... FORECAST CONFIDENCE: MEDIUM TO HIGH. ALTERNATE SCENARIOS: MAY NEED VCSH AT HTS THIS AFTERNOON. BRIEF RAIN IS POSSIBLE AT BOTH PKB/HTS. EKN MAY NOT FOG 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 14 15 16 17 18 19 20 21 22 23 00 01 EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY H H H H H H H H H H H H BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY L 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 H H H H H H H H H H H H AFTER 18Z SUNDAY... IFR POSSIBLE ALONG COLD FRONT...MOVING W TO E...SUN NT INTO MON...AND IN POST-RAIN FOG/STRATUS TUE MORNING. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...TRM/SL NEAR TERM...TRM/26 SHORT TERM...SL LONG TERM...30 AVIATION...26
AREA FORECAST DISCUSSION
NWS TULSA OK
326 PM CDT SAT OCT 5 2013 .DISCUSSION... BAND OF ONGOING CONVECTION IS ALIGNED ALONG THE 850MB FRONT...AND GIVEN THE LATEST RUC PROJECTIONS...THIS BOUNDARY WILL BE ACROSS FAR WESTERN AR INTO EXTREME SE OK BY 00Z AND PUSHING EASTWARD. ANY EVENING PRECIP WILL BE CONFINED TO THIS ZONE BEFORE PUSHING FURTHER EASTWARD AND CLEAR OF THE FORECAST AREA. SKIES WILL CONTINUE TO CLEAR FROM NW TO SE AND ALLOW FOR A COOL SUNDAY MORNING. BREEZY NORTHWEST WINDS WILL DEVELOP SUNDAY WHILE TEMPERATURES REMAIN BELOW SEASONAL NORMALS. WINDS WILL DROP OFF AROUND SUNSET AND ALLOW TEMPS TO FALL QUICKLY. A SEVERAL DAY WARMING TREND COMMENCES MONDAY WITH TEMPS RETURNING TO ABOVE NORMAL READINGS BY MID WEEK. THE WARM AND DRY WEATHER WILL PREVAIL INTO THE WEEKEND WHEN THE NEXT STORM SYSTEM PUSHES INTO THE PLAINS. WILL INTRODUCE LOW PRECIP CHANCES FOR NEXT WEEKEND PENDING THE EVOLUTION OF THIS SYSTEM. && .PRELIMINARY POINT TEMPS/POPS... TUL 46 70 45 75 / 0 0 0 0 FSM 46 71 46 75 / 20 0 0 0 MLC 43 72 43 77 / 10 0 0 0 BVO 40 69 40 75 / 0 10 0 0 FYV 41 65 39 70 / 10 0 0 0 BYV 43 63 44 69 / 30 0 0 0 MKO 42 70 42 75 / 10 0 0 0 MIO 42 66 42 72 / 0 10 0 0 F10 43 71 44 76 / 0 0 0 0 HHW 47 76 44 79 / 30 0 0 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ LONG TERM....07
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
628 PM EDT SAT OCT 5 2013 .SYNOPSIS... A WARM FRONT ACROSS SOUTHERN NEW YORK WILL SLOWLY LIFT NORTHWARD THROUGH THE WEEKEND...AS A MATURE LOW PRESSURE SYSTEM MOVES EAST FROM THE NORTH-CENTRAL PLAINS THROUGH THE MIDWEST/OHIO VALLEY. THE TRAILING COLD FRONT WILL SLOW ITS EASTWARD PROGRESS AS IT CROSSES THE APPALACHIANS...INTERACTING WITH THE REMNANTS OF TROPICAL STORM KAREN. THE DEEP CLOSED UPPER LOW MOVING THROUGH THE OHIO VALLEY WILL DRAW ABUNDANT MOISTURE NORTHWARD ALONG THE NORTH-SOUTH COLD FRONT AND LIKELY PRODUCE GENEROUS RAINFALL AMOUNTS ACROSS CENTRAL PENNSYLVANIA MONDAY INTO TUESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 18Z RADAR LOOP SHOWS ISOLD-SCT CONVECTION DEVELOPING ACRS WRN AND CNTRL PA. LG SCALE FORCING IS FAIRLY NEBULOUS AS THE AREA IS STILL LARGELY UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE CENTERED OVER THE SE STATES. DEWPOINTS IN THE 60S AND UNSEASONABLY WARM AFTN TEMPS IN THE MID 70S-80S IS RESULTING IN SUFFICIENT INSTABILITY WITH RUC ML CAPES BTWN 500-1000 J/KG. SHORTWAVES LIFTING NEWD FROM THE OH VLY MAY ALLOW FOR SOME MORE ORGANIZED CLUSTERS OF STORMS OVER NW PA. SFC WARM FRONT DRAPED NEAR THE PA/NY BORDER MAY PROVIDE SOME FOCUS BUT OVERALL EXPECT SOMEWHAT DISORGANIZED CVRG TO CONVECTIVE ACTIVITY. ADDNL SHORTWAVE ENERGY CRESTING THE UPPER RIDGE MAY CONTINUE TO PRODUCE SCT SHOWERS INTO TONIGHT...MAINLY OVER THE NRN TIER ZONES INVOF THE WARM FRONTAL ZONE. HOWEVER INSTABILITY SHOULD DECREASE AFTER DARK SO CVRG MAY BE LIMITED. EXPECT LOWS TO AGAIN BE VERY MILD/MUGGY FOR THIS TIME OF YEAR...HOLDING IN THE 60S OVERNIGHT IN MOST PLACES. AREAS OF FOG AND LOW STRATUS SHOULD DEVELOP AND PERSIST INTO EARLY SUNDAY MORNING. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... CONSENSUS SHORT-RANGE DATA CONTINUES TO FAVOR THE NRN ZONES WITH THE HIGHEST POPS DURING THE DAY ON SUNDAY...NEAR THE WAVY Q-STNRY/WARM FRONTAL BOUNDARY. A LIGHT LLVL NELY AGEO WIND/ESE SFC WIND MAY KEEP CLOUDS ENTRENCHED OVER THE NERN 1/2 TO 1/3 OF THE CWA THRU THE A.M. HOURS IN SOMEWHAT OF A CAD SFC PATTERN. AN INCREASING SLY GRADIENT FLOW SHOULD PUSH THE BOUNDARY /AND ASSOCD LOWER CLOUDS/ NWD DURING THE AFTN. THIS MAKES FOR A TRICKY TEMP FCST WITH POTENTIAL FOR READINGS TO SOAR WELL INTO THE 80S /PERHAPS 90F NEAR THE MD LINE/ IN THE WARM SECTOR. PLAYED THE MIDDLE GROUND FOR NOW USING A CONS MODEL BLEND...IN AN ATTEMPT TO MITIGATE A POTENTIALLY LARGE MAX T BUST. SUN NGT FOCUS WILL SHIFT TO DEEP CYCLONE CROSSING THE MIDWEST STATES AND ITS ASSOCD COLD FRONT. GUIDANCE CONTINUES TO DISPLAY SOME VARIABILITY WITH THE CLOSED H5 LOW...OWING TO SOME DEGREE OF INFLUENCE TIED TO A SHORTWAVE IN CENTRAL CANADA BRUSHING ACROSS THE TOP OF THE MATURE CYCLONE. SPACING BTWN THE TWO SYSTEMS FAVORS A CONS APPROACH BETWEEN THE NON-NCEP SOLUTIONS LIKE THE 00Z ECMWF WHICH QUICKLY PHASE THE ENERGY...AND THEIR RESPECTIVE NCEP COUNTERPARTS WHICH MAINTAIN A CLOSED CYCLONE FOR A LONGER DURATION. THESE MODEL DIFFS LEAD TO TIMING/PLACEMENT DIFFS WITH THE COLD FRONT AND QPF AXIS...AS REMNANT TROPICAL MSTR IS DRAWN NWD ALONG THE N-S FRONTAL ZONE. BY 12Z MON...THE GFS/EC AND HPC SEEM TO AGREE ON A QPF AXIS CENTERED ALONG THE PA/OH BORDER. THE MAIN RAIN EVENT FOR CENTRAL PA LOOKS TO BE DURING THE DAY MONDAY INTO MONDAY NIGHT. && .LONG TERM /MONDAY THROUGH SATURDAY/... CURRENT 12Z RUNS STAY CONSISTENT IN TIMING THROUGH 06Z MONDAY. AFTER THAT PERIOD THE MODELS BEGIN TO DIVERGE IN TIMING...POSITION AND INTENSIFICATION. THE LATEST NAM SEEMS TO BE THE SLOWEST SOLUTION AND STALLS THE LARGE UPPER LEVEL LOWS PROGRESSION...WITH PASSAGE THROUGH PA EARLY TUESDAY. THE CANADIAN...EC AND GFS MOVE THE SYSTEM THROUGH 6 TO 12 HOURS FASTER. THE EC MOVES THE STRONGEST FORCING TO THE NORTH...AND POSITIVELY TILTS THE TROUGH AS MOVES EASTWARD. THE GFS AND CMC DEEPEN THE TROUGH AS SUCH MADE A TIMING CHANGE TO THE PASSAGE OF THE FRONT...DELAYING IT BY 6-12 HRS...IN LINE WITH THE TREND IN THE MDLS OVER THE LAST 24 HRS. THIS ALSO PREDICATED A NUDGE UPWARD IN THE MAXES FOR MONDAY. A CONSENSUS OF MDL PROG QPF THROUGH THE RAINY PERIOD YIELDS 1 TO 2 INCH AMOUNTS OVER MUCH OF THE AREA...WITH THE HIGHEST AMOUNTS IN THE LOWER SUSQ VALLEY. THIS SEEMS REASONABLE WITH THE MERGING OF MOISTURE FROM KAREN AND THE COLD FRONT. THE RECENT LACK OF RAINFALL SHOULD ALLOW ALL THAT TO BE HANDLED EASILY. HOWEVER...TROPICAL MOISTURE CAN PILE UP QUICKLY AND UNDER- ESTIMATION IS POSSIBLE AT THIS RANGE. AS THE FRONT MOVES OVER THE MOUNTAINS LATE MORNING ON MONDAY...THERE IS A GOOD CHANCE FOR SCATTERED THUNDERSTORMS ALONG THE BOUNDARY. ALSO EXPECT PERIODS OF HEAVY RAINFALL AT AND BEHIND THE FRONT...MONDAY AFTERNOON AND EARLY EVENING. SPC HAS REMOVED THE SLIGHT RISK...THOUGH WITH THE HEAVY RAINFALL AND CONVECTION...WHICH SHOULD BE LOW TOPPED...CANNOT RULE OUT GUSTY WINDS ALONG THE FRONT. AFTER THE RAIN EXITS THE REGION BY TUESDAY MORNING...A RETURN TO RIDGING FOR THE MIDDLE AND END OF THE WEEK WITH DRY AND CONTINUED MILD CONDITIONS. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... MAINLY VFR CONDS WITH LIGHT/VARIABLE WIND WILL CONTINUE THIS EVENING...THOUGH ISOLATED SHOWERS DRIFTING EAST ACROSS THE REGION COULD BRING A BRIEF BOUT OF MVFR CONDITIONS. WILL CONTINUE WITH THE MENTION OF VCSH AT MOST TAF SITES THROUGH 03Z-04Z...AND EVEN A TEMPO FOR HIGH END IFR CONDITIONS AT KJST BETWEEN 00-02Z...AS A CLUSTER OF TSRA /CURRENTLY INVOF KPIT/ TRACKS EWD AT 20-25KTS. CONVECTION WILL WANE DURING THE LATE EVENING WITH THE LOSS OF HEATING AND LACK OF ANY SIGNIFICANT LLVL BOUNDARY. CLEARING SKIES...A CALM WIND AND PLENTY OF LOW LVL MOISTURE WILL SET THE STAGE FOR REDEVELOPMENT OF FOG AND LOW STRATUS LATER TONIGHT. EXPECT MVFR TO IFR /LOCAL LIFR/ RESTRICTIONS TO PERSIST INTO SUNDAY MORNING. LOW CLOUDS COULD LINGER OVER THE ERN TERMINALS THRU SUNDAY MORNING...AS WARM FRONT PIVOTS OVER ZNY SECTOR. OUTLOOK... MON...RAIN/LOW CIGS POSSIBLE. TUE...AM RAIN/LOW CIGS POSSIBLE EAST. WED-THR...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...DANGELO/CERU AVIATION...LAMBERT/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
405 PM EDT SAT OCT 5 2013 .SYNOPSIS... A WARM FRONT ACROSS SOUTHERN NEW YORK WILL SLOWLY LIFT NORTHWARD THROUGH THE WEEKEND...AS A MATURE LOW PRESSURE SYSTEM MOVES EAST FROM THE NORTH-CENTRAL PLAINS THROUGH THE MIDWEST/OHIO VALLEY. THE TRAILING COLD FRONT WILL SLOW ITS EASTWARD PROGRESS AS IT CROSSES THE APPALACHIANS...INTERACTING WITH THE REMNANTS OF TROPICAL STORM KAREN. THE DEEP CLOSED UPPER LOW MOVING THROUGH THE OHIO VALLEY WILL DRAW ABUNDANT MOISTURE NORTHWARD ALONG THE NORTH-SOUTH COLD FRONT AND LIKELY PRODUCE GENEROUS RAINFALL AMOUNTS ACROSS CENTRAL PENNSYLVANIA MONDAY INTO TUESDAY. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... 18Z RADAR LOOP SHOWS ISOLD-SCT CONVECTION DEVELOPING ACRS WRN AND CNTRL PA. LG SCALE FORCING IS FAIRLY NEBULOUS AS THE AREA IS STILL LARGELY UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE CENTERED OVER THE SE STATES. DEWPOINTS IN THE 60S AND UNSEASONABLY WARM AFTN TEMPS IN THE MID 70S-80S IS RESULTING IN SUFFICIENT INSTABILITY WITH RUC ML CAPES BTWN 500-1000 J/KG. SHORTWAVES LIFTING NEWD FROM THE OH VLY MAY ALLOW FOR SOME MORE ORGANIZED CLUSTERS OF STORMS OVER NW PA. SFC WARM FRONT DRAPED NEAR THE PA/NY BORDER MAY PROVIDE SOME FOCUS BUT OVERALL EXPECT SOMEWHAT DISORGANIZED CVRG TO CONVECTIVE ACTIVITY. ADDNL SHORTWAVE ENERGY CRESTING THE UPPER RIDGE MAY CONTINUE TO PRODUCE SCT SHOWERS INTO TONIGHT...MAINLY OVER THE NRN TIER ZONES INVOF THE WARM FRONTAL ZONE. HOWEVER INSTABILITY SHOULD DECREASE AFTER DARK SO CVRG MAY BE LIMITED. EXPECT LOWS TO AGAIN BE VERY MILD/MUGGY FOR THIS TIME OF YEAR...HOLDING IN THE 60S OVERNIGHT IN MOST PLACES. AREAS OF FOG AND LOW STRATUS SHOULD DEVELOP AND PERSIST INTO EARLY SUNDAY MORNING. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... CONSENSUS SHORT-RANGE DATA CONTINUES TO FAVOR THE NRN ZONES WITH THE HIGHEST POPS DURING THE DAY ON SUNDAY...NEAR THE WAVY Q-STNRY/WARM FRONTAL BOUNDARY. A LIGHT LLVL NELY AGEO WIND/ESE SFC WIND MAY KEEP CLOUDS ENTRENCHED OVER THE NERN 1/2 TO 1/3 OF THE CWA THRU THE A.M. HOURS IN SOMEWHAT OF A CAD SFC PATTERN. AN INCREASING SLY GRADIENT FLOW SHOULD PUSH THE BOUNDARY /AND ASSOCD LOWER CLOUDS/ NWD DURING THE AFTN. THIS MAKES FOR A TRICKY TEMP FCST WITH POTENTIAL FOR READINGS TO SOAR WELL INTO THE 80S /PERHAPS 90F NEAR THE MD LINE/ IN THE WARM SECTOR. PLAYED THE MIDDLE GROUND FOR NOW USING A CONS MODEL BLEND...IN AN ATTEMPT TO MITIGATE A POTENTIALLY LARGE MAX T BUST. SUN NGT FOCUS WILL SHIFT TO DEEP CYCLONE CROSSING THE MIDWEST STATES AND ITS ASSOCD COLD FRONT. GUIDANCE CONTINUES TO DISPLAY SOME VARIABILITY WITH THE CLOSED H5 LOW...OWING TO SOME DEGREE OF INFLUENCE TIED TO A SHORTWAVE IN CENTRAL CANADA BRUSHING ACROSS THE TOP OF THE MATURE CYCLONE. SPACING BTWN THE TWO SYSTEMS FAVORS A CONS APPROACH BETWEEN THE NON-NCEP SOLUTIONS LIKE THE 00Z ECMWF WHICH QUICKLY PHASE THE ENERGY...AND THEIR RESPECTIVE NCEP COUNTERPARTS WHICH MAINTAIN A CLOSED CYCLONE FOR A LONGER DURATION. THESE MODEL DIFFS LEAD TO TIMING/PLACEMENT DIFFS WITH THE COLD FRONT AND QPF AXIS...AS REMNANT TROPICAL MSTR IS DRAWN NWD ALONG THE N-S FRONTAL ZONE. BY 12Z MON...THE GFS/EC AND HPC SEEM TO AGREE ON A QPF AXIS CENTERED ALONG THE PA/OH BORDER. THE MAIN RAIN EVENT FOR CENTRAL PA LOOKS TO BE DURING THE DAY MONDAY INTO MONDAY NIGHT. && .LONG TERM /MONDAY THROUGH SATURDAY/... CURRENT 12Z RUNS STAY CONSISTENT IN TIMING THROUGH 06Z MONDAY. AFTER THAT PERIOD THE MODELS BEGIN TO DIVERGE IN TIMING...POSITION AND INTESIFICATION. THE LATEST NAM SEEMS TO BE THE SLOWEST SOLUTION AND STALLS THE LARGE UPPER LEVEL LOWS PROGRESSION...WITH PASSAGE THROUGH PA EARLY TUESDAY. THE CANADIAN...EC AND GFS MOVE THE SYSTEM THROUGH 6 TO 12 HOURS FASTER. THE EC MOVES THE STRONGEST FORCING TO THE NORTH...AND POSITIVELY TILTS THE TROUGH AS MOVES EASTWARD. THE GFS AND CMC DEEPEN THE TROUGH AS SUCH MADE A TIMING CHANGE TO THE PASSAGE OF THE FRONT...DELAYING IT BY 6-12 HRS...IN LINE WITH THE TREND IN THE MDLS OVER THE LAST 24 HRS. THIS ALSO PREDICATED A NUDGE UPWARD IN THE MAXES FOR MONDAY. A CONSENSUS OF MDL PROG QPF THROUGH THE RAINY PERIOD YIELDS 1 TO 2 INCH AMOUNTS OVER MUCH OF THE AREA...WITH THE HIGHEST AMOUNTS IN THE LOWER SUSQ VALLEY. THIS SEEMS REASONABLE WITH THE MERGING OF MOISTURE FROM KAREN AND THE COLD FRONT. THE RECENT LACK OF RAINFALL SHOULD ALLOW ALL THAT TO BE HANDLED EASILY. HOWEVER...TROPICAL MOISTURE CAN PILE UP QUICKLY AND UNDER- ESTIMATION IS POSSIBLE AT THIS RANGE. AS THE FRONT MOVES OVER THE MOUNTAINS LATE MORNING ON MONDAY...THERE IS A GOOD CHANCE FOR SCATTERED THUNDERSTORMS ALONG THE BOUNDARY. ALSO EXPECT PERIODS OF HEAVY RAINFALL AT AND BEHIND THE FRONT...MONDAY AFTERNOON AND EARLY EVENING. SPC HAS REMOVED THE SLIGHT RISK...THOUGH WITH THE HEAVY RAINFALL AND CONVECTION...WHICH SHOULD BE LOW TOPPED...CANNOT RULE OUT GUSTY WINDS ALONG THE FRONT. AFTER THE RAIN EXITS THE REGION BY TUESDAY MORNING...A RETURN TO RIDGING FOR THE MIDDLE AND END OF THE WEEK WITH DRY AND CONTINUED MILD CONDITIONS. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... VFR CONDS CONTINUE THIS AFTN WITH SCT-BKN 3-5KFT MOD CUMULUS BASES AND ISOLD/WDLY SCT CONVECTION DEVELOPING ACROSS THE AIRSPACE. BRIEF RESTRICTIONS TO MVFR/IFR ARE POSSIBLE UNDER DIRECT HITS FROM SHOWERS AND TSTMS. ADDED SOME VCSH MENTION BUT OVERALL CVRG IS LIMITED. AMDS WILL NEED TO BE ISSUED FOR BRIEF SHRA/TSRA IMPACTS. CONVECTION SHOULD WANE INTO THE EVE WITH THE LOSS OF INSTABILITY. CLEARING SKIES...A CALM WIND AND PLENTY OF LOW LVL MOISTURE WILL SET THE STAGE FOR REDEVELOPMENT OF FOG AND LOW STRATUS TONIGHT. EXPECT MVFR TO IFR /LOCAL LIFR/ RESTRICTIONS TO PERSIST INTO SUNDAY MORNING. LOW CLOUDS COULD LINGER OVER THE ERN TERMINALS THRU SUNDAY MORNING...AS WARM FRONT PIVOTS OVER ZNY SECTOR. OUTLOOK... MON...RAIN/LOW CIGS POSSIBLE. TUE...AM RAIN/LOW CIGS POSSIBLE EAST. WED-THR...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...DANGELO/CERU AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
258 PM EDT SAT OCT 5 2013 .SYNOPSIS... A WARM FRONT ACROSS SOUTHERN NEW YORK WILL SLOWLY LIFT NORTHWARD THROUGH THE WEEKEND...AS A MATURE LOW PRESSURE SYSTEM MOVES EAST FROM THE NORTH-CENTRAL PLAINS THROUGH THE MIDWEST/OHIO VALLEY. THE TRAILING COLD FRONT WILL SLOW ITS EASTWARD PROGRESS AS IT CROSSES THE APPALACHIANS...INTERACTING WITH THE REMNANTS OF TROPICAL STORM KAREN. THE DEEP CLOSED UPPER LOW MOVING THROUGH THE OHIO VALLEY WILL DRAW ABUNDANT MOISTURE NORTHWARD ALONG THE NORTH-SOUTH COLD FRONT AND LIKELY PRODUCE GENEROUS RAINFALL AMOUNTS ACROSS CENTRAL PENNSYLVANIA MONDAY INTO TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... 18Z RADAR LOOP SHOWS ISOLD-SCT CONVECTION DEVELOPING ACRS WRN AND CNTRL PA. LG SCALE FORCING IS FAIRLY NEBULOUS AS THE AREA IS STILL LARGELY UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE CENTERED OVER THE SE STATES. DEWPOINTS IN THE 60S AND UNSEASONABLY WARM AFTN TEMPS IN THE MID 70S-80S IS RESULTING IN SUFFICIENT INSTABILITY WITH RUC ML CAPES BTWN 500-1000 J/KG. SHORTWAVES LIFTING NEWD FROM THE OH VLY MAY ALLOW FOR SOME MORE ORGANIZED CLUSTERS OF STORMS OVER NW PA. SFC WARM FRONT DRAPED NEAR THE PA/NY BORDER MAY PROVIDE SOME FOCUS BUT OVERALL EXPECT SOMEWHAT DISORGANIZED CVRG TO CONVECTIVE ACTIVITY. ADDNL SHORTWAVE ENERGY CRESTING THE UPPER RIDGE MAY CONTINUE TO PRODUCE SCT SHOWERS INTO TONIGHT...MAINLY OVER THE NRN TIER ZONES INVOF THE WARM FRONTAL ZONE. HOWEVER INSTABILITY SHOULD DECREASE AFTER DARK SO CVRG MAY BE LIMITED. EXPECT LOWS TO AGAIN BE VERY MILD/MUGGY FOR THIS TIME OF YEAR...HOLDING IN THE 60S OVERNIGHT IN MOST PLACES. AREAS OF FOG AND LOW STRATUS SHOULD DEVELOP AND PERSIST INTO EARLY SUNDAY MORNING. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... CONSENSUS SHORT-RANGE DATA CONTINUES TO FAVOR THE NRN ZONES WITH THE HIGHEST POPS DURING THE DAY ON SUNDAY...NEAR THE WAVY Q-STNRY/WARM FRONTAL BOUNDARY. A LIGHT LLVL NELY AGEO WIND/ESE SFC WIND MAY KEEP CLOUDS ENTRENCHED OVER THE NERN 1/2 TO 1/3 OF THE CWA THRU THE A.M. HOURS IN SOMEWHAT OF A CAD SFC PATTERN. AN INCREASING SLY GRADIENT FLOW SHOULD PUSH THE BOUNDARY /AND ASSOCD LOWER CLOUDS/ NWD DURING THE AFTN. THIS MAKES FOR A TRICKY TEMP FCST WITH POTENTIAL FOR READINGS TO SOAR WELL INTO THE 80S /PERHAPS 90F NEAR THE MD LINE/ IN THE WARM SECTOR. PLAYED THE MIDDLE GROUND FOR NOW USING A CONS MODEL BLEND...IN AN ATTEMPT TO MITIGATE A POTENTIALLY LARGE MAX T BUST. SUN NGT FOCUS WILL SHIFT TO DEEP CYCLONE CROSSING THE MIDWEST STATES AND ITS ASSOCD COLD FRONT. GUIDANCE CONTINUES TO DISPLAY SOME VARIABILITY WITH THE CLOSED H5 LOW...OWING TO SOME DEGREE OF INFLUENCE TIED TO A SHORTWAVE IN CENTRAL CANADA BRUSHING ACROSS THE TOP OF THE MATURE CYCLONE. SPACING BTWN THE TWO SYSTEMS FAVORS A CONS APPROACH BETWEEN THE NON-NCEP SOLUTIONS LIKE THE 00Z ECMWF WHICH QUICKLY PHASE THE ENERGY...AND THEIR RESPECTIVE NCEP COUNTERPARTS WHICH MAINTAIN A CLOSED CYCLONE FOR A LONGER DURATION. THESE MODEL DIFFS LEAD TO TIMING/PLACEMENT DIFFS WITH THE COLD FRONT AND QPF AXIS...AS REMNANT TROPICAL MSTR IS DRAWN NWD ALONG THE N-S FRONTAL ZONE. BY 12Z MON...THE GFS/EC AND HPC SEEM TO AGREE ON A QPF AXIS CENTERED ALONG THE PA/OH BORDER. THE MAIN RAIN EVENT FOR CENTRAL PA LOOKS TO BE DURING THE DAY MONDAY INTO MONDAY NIGHT. && .LONG TERM /MONDAY THROUGH SATURDAY/... MADE A TIMING TWEAK TO THE PASSAGE OF THE FRONT...DELAYING IT BY 6-12 HRS...IN LINE WITH THE TREND IN THE MDLS OVER THE LAST 24 HRS. THIS ALSO PREDICATED A NUDGE UPWARD IN THE MAXES FOR MONDAY. A CONSENSUS OF MDL PROG QPF THROUGH THE RAINY PERIOD YIELDS 1 TO 2 INCH AMOUNTS OVER MUCH OF THE AREA. THIS SEEMS REASONABLE WITH THE MERGING OF MOISTURE FROM KAREN AND THE COLD FRONT. THE RECENT LACK OF RAINFALL SHOULD ALLOW ALL THAT TO BE HANDLED EASILY. HOWEVER...TROPICAL MOISTURE CAN PILE UP QUICKLY AND UNDER- ESTIMATION IS POSSIBLE AT THIS RANGE. PREV DISC FOLLOWS... MAIN FEATURE FOR THE LONG TERM WILL BE A CLOSED UPPER LOW THAT SLOWLY MOVES FROM THE LOWER OHIO VALLEY TO THE ST. LAWRENCE VALLEY BY EARLY WEEK. THIS FEATURE WILL HELP DRAW SOME OF THE MOISTURE ASSOCIATED WITH TROPICAL STORM/DEPRESSION KAREN INTO THE AREA. WHILE NOT A DIRECT HIT OVER THE REGION...EXPECT STORM TOTAL AMOUNTS FROM LATE SUNDAY THROUGH TUESDAY TO BE IN THE 1 TO 1.5 INCH RANGE. LATEST MODELS DELAY THE ARRIVAL OF THE LEADING AREA OF PRECIPITATION/FRONTAL BOUNDARY TOWARD SUNDAY NIGHT. HAVE BACKED OFF POPS FOR SUNDAY AFTERNOON AS A RESULT. THIS WILL KEEP MILD AIR ACROSS THE REGION THROUGH THE WEEKEND. AFTER THE RAIN EXITS THE REGION BY TUESDAY MORNING...A RETURN TO RIDGING FOR THE MIDDLE AND END OF THE WEEK WITH DRY AND CONTINUED MILD CONDITIONS. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR CONDS CONTINUE THIS AFTN WITH SCT-BKN 3-5KFT MOD CUMULUS BASES AND ISOLD/WDLY SCT CONVECTION DEVELOPING ACROSS THE AIRSPACE. BRIEF RESTRICTIONS TO MVFR/IFR ARE POSSIBLE UNDER DIRECT HITS FROM SHOWERS AND TSTMS. ADDED SOME VCSH MENTION BUT OVERALL CVRG IS LIMITED. AMDS WILL NEED TO BE ISSUED FOR BRIEF SHRA/TSRA IMPACTS. CONVECTION SHOULD WANE INTO THE EVE WITH THE LOSS OF INSTABILITY. CLEARING SKIES...A CALM WIND AND PLENTY OF LOW LVL MOISTURE WILL SET THE STAGE FOR REDEVELOPMENT OF FOG AND LOW STRATUS TONIGHT. EXPECT MVFR TO IFR /LOCAL LIFR/ RESTRICTIONS TO PERSIST INTO SUNDAY MORNING. LOW CLOUDS COULD LINGER OVER THE ERN TERMINALS THRU SUNDAY MORNING...AS WARM FRONT PIVOTS OVER ZNY SECTOR. OUTLOOK... MON...RAIN/LOW CIGS POSSIBLE. TUE...AM RAIN/LOW CIGS POSSIBLE EAST. WED-THR...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...DANGELO/TYBURSKI AVIATION...STEINBUGL
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
305 PM MDT SAT OCT 5 2013 .SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT ISSUED AT 301 PM MDT SAT OCT 5 2013 THE STORM CONTINUES TO WIND DOWN SLOWLY FOR THE BLACK HILLS REGION THIS AFTERNOON. A STRONG CLOSED LOW OVER EASTERN SOUTH DAKOTA IS MAKING A LITTLE PROGRESS EASTWARD THIS AFTERNOON. THE RESULT FOR THE WESTERN HALF OF THE STATE IS DECREASING SNOWFALL AND WIND AS THE WEAKENING BAND OF PRECIPITATION AND STRONG WIND SHFTS EASTWARD. THE 18Z HRRR SHOWS THE SURFACE LOW CENTER WEAKENING RAPIDLY AND REFORMING OVER MINNESOTA DURING THE NEXT SEVERAL HOURS. AS THE SYSTEM MOVES INTO CENTRAL SOUTH DAKOTA BOTH THE PRECIPITATION RATE AND DURATION OF STRONG WINDS ARE EXPECTED TO DECREASE RESULTING IN A LESS POTENT EVENT IN THOSE PARTS. A MUCH WELCOME DAY OF BLUE SKIES AND SUNSHINE ARE IN STORE FOR SUNDAY AS A TRANSITORY HIGH PRESSURE RIDGE SHIFTS INTO THE HIGH PLAINS. GUIDANCE WARMING SEEMS A LITTLE TOO AGRESSIVE CONSIDERING THE EXTENSIVE SNOWPACK WE`VE ACQUIRED SO TEMPS WERE TRIMMED DOWN A BIT. THIS IS BETTER THAN A RAPID MELTOFF ANYWAY. WILL HAVE TO KEEP AN EYE ON HOW THE STREAMS RESPOND OVER THE NEXT COUPLE OF DAYS. THE MILD SUNNY WEATHER IS FORECAST TO CONTINUE MONDAY AS THE RIDGE LINGERS OVER THE REGION. && .LONG TERM...MONDAY THROUGH SATURDAY ISSUED AT 301 PM MDT SAT OCT 5 2013 PROGRESSIVE LONG WAVE RIDGE BUILDS IN BEHIND THE RECORD-BREAKING BLIZZARD... MOVING QUICKLY FROM NEAR 110W ON MON TO JUST E OF 100W ON TUE AND TO 85W ON WED. AS IT DOES SO...A NEW LONG WAVE TROF IS CARVED OUT IN THE WEST. GFS CONTINUES TREND OF LAST SEVERAL RUNS IN SPLITTING OFF A NRN STREAM SHORT WAVE AND MOVING IT ACROSS WRN CAN WHILE THE STRONGER PORTION OF THE WAVE DIGS S WARD INTO CA. BY 12Z WED A CLOSED LOW IS SHOWN OVER NRN CA. THE DIGGING PROCESS IS COMPLETED BY THU AT 12Z AND THE LOW IS FCST TO MOVE OUT TO THE NE...PERHAPS TO SE SD BY 12Z SAT. THIS RUN OF GFS IS SLIGHTLY FARTHER S AND E THAN YESTERDAY`S. WHILE THE TRACK IS REMINISCENT OF OUR PRESENT STORM...1000 TO 500MB THICKNESSES ARE PRESENTLY FCST TO BE WELL ABOVE SNOW RELATED VALUES AND THE UPPER LOW IS FAR LESS INTENSE. BUT IT IS EARLY IN THE GAME. ACCEPTED THE EXTENDED INIT TEMPS...THOUGH THEY ARE MUCH BELOW GFS MOS GUIDANCE FOR WED AND THU. THINKING IS THAT THERE WILL STILL BE SOME WET GROUND FROM THE HEAVY SNOW AND THAT THE STORM-FOLLOWING RIDGE IS FCST TO MOVE E WARD SO QUICKLY THAT UPPER LEVEL COOLING WILL ALREADY BE UNDERWAY AS THE TROF IN THE W INTENSIFIES AND APPROACHES THE AREA. CLOUDS...POPS...AND PRECIP BROUGHT IN THU NIGHT INTO SAT IN LINE WITH APPROACHING CLOSED LOW. && .AVIATION...FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING ISSUED AT 301 PM MDT SAT OCT 5 2013 FOR 12Z TAF ISSUANCE. A WIDESPREAD AREA OF SNOW CONTINUES TO BLANKET THE AREA...AND VERY STRONG NORTHWEST WINDS ARE PERSISTING. LIFR AND IFR CONDITIONS WILL PREDOMINATE OVER WESTERN SD IN SNOW AND BLOWING SNOW THROUGH MID MORNING SATURDAY. PRECIPITATION WILL END FROM THE WEST WITH IMPROVING CEILINGS AND VISIBILITIES. BY SUNSET...EXPECT MOSTLY VFR CONDITIONS. STRONG WINDS WILL DIMINISH VERY SLOWLY DURING THE AFTERNOON SATURDAY. NO OBSERVATIONS HAVE BEEN AVAILABLE SINCE FRIDAY AFTERNOON FROM KRAP DUE TO COMMUNICATIONS ISSUES. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...WINTER STORM WARNING UNTIL 6 PM MDT THIS EVENING FOR SDZ044. WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR SDZ046- 047-049. BLIZZARD WARNING UNTIL 6 PM MDT THIS EVENING FOR SDZ014-032-043. WY...NONE. && $$ SHORT TERM...CARPENTER LONG TERM...BARBER AVIATION...BARBER
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1154 AM CDT SAT OCT 5 2013 .AVIATION... BASED ON CURRENT MVMT...FRONT SHOULD BE NEAR CLL AROUND 21Z...IAH 2Z & GLS 5Z. MODELS SHOWING SOME SPOTTY SHRA GENERALLY E OF HWY 288 & I-45 THRU THE DAY AND KEPT VCSHS IN TAFS. DID LOWER CIGS OVERNIGHT IN THE WAKE OF THE FRONT INTO MVFR & HIGH IFR TERRITORY AS SOME MOISTURE GETS TRAPPED BELOW SHARP INVERSION. WILL ALSO BE KEEPING AN EYE ON THE POTENTIAL FOR SOME POST FRONTAL PRECIP (WITH H85 FRONT LOOKING TO BE FOCUS) OVERNIGHT. MAJORITY OF MODELS THAT DO SHOW THIS OCCURRING KEEP IT MOSTLY WEST AND EAST OF OUR TERMINALS. WILL LEAVE MENTION OUT OF 18Z TAFS ATTM AND SEE HOW IT PLAYS OUT. LOOK CIGS TO LIFT & CLEAR OUT FROM NW-SE FROM MID MORNING THRU MID/LATE AFTN SUNDAY. 47 && .PREV DISCUSSION... /ISSUED 1021 AM CDT SAT OCT 5 2013/ THE COLD FRONT WAS PROGRESSING STEADILY ACROSS THE NORTHERN AND CENTRAL PORTIONS OF THE STATE. UPDATED THE WIND SHIFT WITH THE LATEST RAP FORECAST. A 12Z ANALYSIS SHOWED A SURFACE RIDGE OVER THE TEXAS COASTAL AREAS WITH LOW-LEVEL MOISTURE STREAMING NORTHWARD FROM THE GULF INTO AREAS MAINLY EAST OF FREEPORT. OVER MOST OF THE FORECAST AREA THE AIR MASS WAS FAIRLY DRY AND CAPPED AND EXPECT THAT MOST CONVECTION THIS AFTERNOON WILL BE CONFINED TO THE EASTERN AND NORTHERN SET OF COUNTIES WHERE THE DEEPER MOISTURE AND COOLER AIRMASS ALOFT RESIDES. WILL UPDATE MAINLY FOR THE WINDS. OTHERWISE...THE REMAINDER OF THE FORECAST LOOKS ON TARGET. 40 && .PRELIMINARY POINT TEMPS/POPS... COLLEGE STATION (CLL) 89 58 81 52 83 / 20 20 10 0 0 HOUSTON (IAH) 92 62 80 53 83 / 50 30 10 0 0 GALVESTON (GLS) 89 69 81 65 80 / 40 30 20 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM. && $$
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
100 PM EDT SAT OCT 5 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH TONIGHT. A LOW PRESSURE SYSTEM TRACKING FROM THE CENTRAL PLAINS TO THE GREAT LAKES WILL PUSH A STRONG COLD FRONT THROUGH THE AREA ON MONDAY. THE LOW AND COLD FRONT WILL MOVE OFFSHORE BY TUESDAY NIGHT. && .NEAR TERM /THROUGH TONIGHT/... AS OF 945 AM EDT SATURDAY... SHOULD BE A WARM...POTENTIALLY RECORD BREAKING DAY...ESPECIALLY AT BLACKSBURG/BLUEFIELD (SEE CLIMATE SECTION BELOW)...AS HIGH PRESSURE RESIDES OVERHEAD. FOG WILL BE LIFTING ACROSS THE VALLEYS...BUT HAS HELD STRONG IN THE GREENBRIER VALLEY. TEMPS STARTING TO RUN A COUPLE DEGREES WARMER OUT EAST THAN CURRENT FORECAST...SO BUMPED UP HIGHS A COUPLE DEGREES...LOOKING AT UPPER 70S TO LOWER 80S ACROSS THE HIGHER TERRAIN...TO MID TO UPPER 80S VALLEYS AND POINTS EAST OF THE BLUE RIDGE. PREVIOUS VALID DISCUSSION... SURFACE HIGH PRESSURE AND A 500 MB RIDGE WILL REMAIN OVER THE CENTRAL AND SOUTHERN APPALACHIANS THROUGH TONIGHT. LOCAL WRF AS WELL AS HRRR AND LATEST RAP GUIDANCE SUGGEST THERE IS STILL A LOW CHANCE OF SHOWERS THIS AFTERNOON...MAINLY NORTH OF I-64. ASIDE FROM THE WEST TO SOUTHWEST UPSLOPE WINDS...LITTLE IN THE WAY OF SHORT WAVES TO HELP TRIGGER ANY PRECIPITATION. ANY SCATTERED TO BROKEN CU THAT DEVELOPS TODAY WILL DISSIPATE THIS EVENING. USED A BLEND OF BIAS CORRECTED MAV/MET GUIDANCE FOR OVERNIGHT LOWS. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 453 AM EDT SATURDAY... MODELS REMAINING CONSISTENT WITH MOVING A COLD FRONT AND ASSOCIATED SHOWERS INTO THE OHIO VALLEY ON SUNDAY. MODELS HAVE SLOWED DOWN THE FRONTS MOVEMENT INTO THE AREA SUNDAY NIGHT AND ACROSS THE REGION MONDAY/MONDAY NIGHT. THE SLOWER PROGRESSION OF THE FRONT IS DUE TO UPPER LEVEL FORCING BECOMING DETACHED FROM THE LOW LEVEL BOUNDARY. TROPICAL STORM KAREN OR REMNANTS OF...MAY ALSO PLAYING A PART IN SLOWING THE FRONT DOWN TO A CRAWL AS IT CROSSES OVER THE AREA. BASED ON THE 00Z MODEL TRENDS...LOWERED POPS INTO SUNDAY EVENING. MEASURABLE RAIN BEGINS TO TRACK ACROSS THE SOUTHWEST EARLY MONDAY MORNING...THEN SPREADS ACROSS THE REST OF THE MOUNTAINS AROUND SUNRISE. RAIN CHANCES INCREASE EAST OF THE BLUE RIDGE TOWARD THE AFTERNOON AND CONTINUES INTO THE EVENING. WITH A COLD FRONT INTERACTING WITH TROPICAL MOISTURE...IT WAS A NO BRAINER TO INCREASE POPS TO 100 PERCENT MONDAY. WITH THE FRONT BEING SLOWER...ALSO INCREASED POPS MONDAY EVENING...TRENDING DOWN TUESDAY MORNING AS THE FRONT TRACKS EAST. WITH SHOWERS NOT DUE TO MOVE ACROSS THE PIEDMONT UNTIL THE AFTERNOON...THERE MAY BE ENOUGH INSTABILITIES TO GENERATE A RUMBLE OF THUNDER. IF ENOUGH INSTABILITIES IS PRESENT WHEN THE 850 JET PASSES OVERHEAD...A STORM OR TWO MAY PRODUCE STRONG WINDS. FOR THE MOST PART...THIS WILL BE A HYDRO EVENT. PWATS ON MONDAY APPROACH 2 INCHES WHICH IS CLOSE TO BEING 2 STANDARD DEVIATIONS ABOVE NORMAL. RAINFALL AMOUNTS FROM SUNDAY NIGHT INTO MONDAY EVENING SHOULD RANGE FROM 1 TO 2 INCHES. WITH THE RECENT DRY SPELL...THE FORECAST AREA SHOULD NOT SEE ANY WIDESPREAD WATER PROBLEMS. LOCALIZE FLOODING IS NOT OUT OF THE QUESTION IN POOR DRAINAGE AREAS...ESPECIALLY IF HIGH RAINFALL RATES OR TRAINING OF STORMS PERSIST OVER AN AREA FOR SEVERAL HOURS. THE UPPER LEVEL RIDGE THAT BROUGHT WARMTH TO THE AREA ON SATURDAY WILL BEGIN TO SLIDE OFF THE SOUTHEAST COAST ON SUNDAY. WITH THE FRONT REMAINING WEST OF THE AREA FOR MOST OF SUNDAY...WARMER THAN NORMAL TEMPERATURES WILL AGAIN COVER THE REGION. SUNDAY TEMPERATURES WILL RANGE FROM THE LOW TO MID 80S ACROSS THE WEST TO MID TO UPPER 80S IN THE EAST. A DRAMATIC COOL DOWN COMES MONDAY WITH THE RAIN. FORECASTED HIGH TEMPERATURES MONDAY WILL RANGE FROM THE MID 60S IN THE WEST TO LOWER 70S ACROSS THE PIEDMONT. && .LONG TERM /TUESDAY THROUGH FRIDAY/... AS OF 1215 PM EDT FRIDAY... FORECAST EARLY IN THE PERIOD CENTERS AROUND THE FRONT/REMNANTS OF KAREN AND THE UPPER TROUGH MOVING ACROSS THE GREAT LAKES/NORTHEAST/MID ATLANTIC. THE LATEST GFS (12Z) CONTINUES TO BE SLOWER...AND IS ACTUALLY SLOWER THAN THE 06Z RUN IN MOVING THE FRONT OUT...WITH A STRONGER UPPER LOW...BUT IS FURTHER EAST WITH KAREN. PER NHC/WPC...WILL BE LEANING TOWARD THE 00Z ECMWF AND THE PREVIOUS FORECAST. THERE WILL STILL BE LINGERING SHOWERS ACROSS THE PIEDMONT TUESDAY AND NOT OUT OF THE QUESTION THAT STRONG SUBSIDENCE BEHIND THE DEPARTING TROPICAL SYSTEM MAY START TO DRY THINGS OUT FASTER. FOR MID TO LATE WEEK...THE FORECAST MAINTAINS A CHALLENGE IN TERMS OF SFC HIGH PRESSURE WEDGING SOUTH INTO OUR AREA...WHILE A RESIDUAL UPPER TROUGH LINGERS OVER THE SOUTHEAST. QUESTION WILL BE WHERE DEEPER MOISTURE RESIDES. WITH THE ECMWF THINK MOST OF THE CLOUD COVER WILL BE HUGGING OUR SOUTHEAST CWA WITH MORE RESIDING ACROSS THE SOUTHEAST...WHILE THE WESTERN CWA SEES MORE SUN DURING THE DAY. TEMPERATURES GIVEN A LIGHT NE-E FLOW WILL BE CLOSER TO NORMAL...WITH THE THREAT OF RAIN BEING LESS THAN 10 PERCENT. && .AVIATION /18Z SATURDAY THROUGH WEDNESDAY/... AS OF 100 PM EDT SATURDAY... AXIS OF UPPER RIDGE WILL CROSS THE AREA AS WE BEGIN TO COME UNDER THE INFLUENCE OF UPSTREAM SYSTEM APPROACHING FROM THE MIDWEST. THERE WILL BE A LITTLE SHORT WAVE ENERGY MOVING THROUGH THE ARE EARLY IN THE TAF PERIOD...BUT SIGNIFICANT MOISTURE IS LACKING AND CAPES ARE MEAGER. WHILE AN ISOLATED SHOWER CAN NOT BE RULED OUT IT DOES NOT WARRANT A MENTION IN THE TAFS. WILL GO WITH BKN VFR CIGS WEST AND NORTH WITH JUST SCT EAST AND SOUTH. EXPECTING MID/HIGH CLOUDS TO REMAIN MOSTLY TO OUR NORTH AND ALLOW FOR DECENT RAD COOLING OVERNIGHT. THUS...EXPECTING KLWB/KBCB TO FOG IN AGAIN TONIGHT BUT ONLY MVFR AT OTHER SITES. SHOULD STAY VFR AT KBLF AS WINDS COME AROUND TO A SWLY DIRECTION TO PROHIBIT FOG. .EXTENDED AVIATION... LOOKS LIKE COLD FRONT APPROACHING FROM THE WEST WILL BE THE MAIN PLAYER FOR OUR WEATHER SUNDAY NIGHT THROUGH MONDAY AS TROPICAL SYSTEM REMAINS TO OUR SOUTH. AVIATION CONDITIONS WILL BE QUITE POOR THIS PERIOD WITH RAIN...GUSTY WINDS...AND LIKELY IFR CONDITIONS. HOWEVER...THINGS WILL IMPROVE CONSIDERABLY BEHIND THE FRONT TUESDAY...AND THE REMAINDER OF THE WEEK LOOKS GOOD FOR AVIATION WITH THE EXPECTATION OF DIURNAL FOG FORMATION. && .CLIMATE... RECORD HIGH TEMPS FOR SATURDAY. ROANOKE 98/1941 LYNCHBURG 96/1941 DANVILLE 98/1951 BLACKSBURG 86/1954 BLUEFIELD 85/2007 && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ SYNOPSIS...AMS/WP NEAR TERM...AMS/WP SHORT TERM...RCS LONG TERM...JH/WP AVIATION...MBS CLIMATE...RCS
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1213 PM CDT SAT OCT 5 2013 .UPDATE... THE WARM FRONT IS INCHING NORTHWARD THIS MORNING. DENSE FOG IN SOUTHEAST WI IMPROVED TO 1 TO 2 MILES...WHILE SHEBOYGAN AND PORT WASHINGTON REMAIN SOCKED IN WITH THE LIGHT SOUTHEAST FLOW OFF THE LAKE ON THE NORTH SIDE OF THE WARM FRONT. DENSE FOG ADVISORY IN EFFECT UNTIL MID AFTERNOON THERE. STRENGTHENING LOW LEVEL JET AND MOISTURE CONVERGENCE WITH A VORT MAX MOVING OUT OF EASTERN IOWA IS LEADING TO INCREASING SHOWER COVERAGE IN SOUTH CENTRAL WISCONSIN LATE THIS MORNING. THESE SHOWERS WILL EXPAND/PROGRESS EASTWARD THROUGH EARLY AFTERNOON. 1000 J/KG OF MU CAPE ALLOWING FOR A FEW EMBEDDED THUNDERSTORMS. WATCHING THE MORE DISCRETE CELLS IN NORTH CENTRAL IL FOR STRENGTHENING...AS THAT REGION HAS HIGHER CAPE AND BULK SHEAR VALUES. THESE VALUES WILL GRADUALLY MOVE INTO SOUTHERN WI...BUT FOG AND LOW CLOUDS OVER SOUTHERN WI WILL SLOW IT DOWN. LATEST HRRR KEEPS THE FORECAST REFLECTIVITY FOR MIDDAY RATHER LIGHT. HIGH PRECIPITABLE WATER VALUES WILL LEAD TO EFFICIENT RAINFALL THOUGH...SO WILL NEED TO WATCH FOR FLOODING POTENTIAL ESPECIALLY IN URBAN AREAS. WATER VAPOR IMAGERY SHOWS A STRONGER SHORTWAVE DOWN IN MISSOURI THAT IS NOW FORECAST TO MOVE THROUGH NORTHEAST IL AROUND 00Z ALONG THE SURFACE FRONTAL TROUGH INSTEAD OF SOUTHEAST WI. HOWEVER...THE SURFACE TROUGH WILL EXTEND BACK INTO WEST CENTRAL WI...SO WHILE THE STRONGEST 500MB SHORTWAVE WILL BE ABSENT...THERE WILL STILL BE SURFACE CONVERGENCE...MODERATE BULK SHEAR...UPPER DIVERGENCE AND STRONG 700MB OMEGA OVER SOUTHERN WI AT 00Z TO ALLOW FOR THUNDERSTORMS. ANOTHER ROUND OF WIDESPREAD CONVECTION IS EXPECTED WITH THIS FEATURE...MOST LIKELY BETWEEN 05 PM AND 10 PM IN THE MKX FORECAST AREA. THIS WILL BE THE PERIOD FOR HEAVIEST RAIN AND STRONGEST WIND GUSTS AND BEST POTENTIAL FOR SEVERE GUSTS. UNIDIRECTIONAL WIND THROUGH THE COLUMN WILL LEAD TO THUNDERSTORMS QUICKLY DEVELOPING INTO LINE SEGMENTS. && .AVIATION/18Z TAFS/... FOG CONTINUES TO THIN EXCEPT TOWARD SHEBOYGAN AND PORT WASHINGTON AHEAD OF THE WARM FRONT AND WITH THE INFLUENCE OF MARINE AIR. CIGS WILL REMAIN IFR OR LOWER UNTIL SCATTERED SHOWERS WITH A FEW EMBEDDED THUNDERSTORMS SPREAD ACROSS SOUTH CENTRAL AND SOUTHEAST WI THROUGH EARLY AFTERNOON. ANOTHER ROUND OF WIDESPREAD CONVECTION WITH HEAVY RAIN AND STRONG WIND GUSTS WILL IMPACT SOUTHERN WI BETWEEN 5 PM TO 10 PM. CONVECTION WILL END FROM WEST TO EAST SOON AFTER MIDNIGHT AS OCCLUDED FRONT SLIDES EAST OF AREA. && .MARINE... WILL CONTINUE DENSE FOG ADVY INTO THE EVENING AS WARM...MOIST AIR CONTINUES TO MOVE ACROSS COOLER NEAR SHORE WATERS OF LAKE MI. SCATTERED MORNING AND EARLY AFTN CONVECTION WL GIVE WAY TO A MORE WIDESPREAD PERIOD LATER THIS AFTN AND EVE. && .PREV DISCUSSION... /ISSUED 305 AM CDT SAT OCT 5 2013/ TODAY AND TONIGHT - CONFIDENCE...MEDIUM. WL EXPAND DENSE FOG ADVY INTO MORE OF SOUTHEAST THROUGH THE EARLY MORNING AND CONTINUE 14Z EXPIRATION. AS WARM FRONT IN NORTHERN IL BEGINS TO SHIFT NWD...DENSE FOG SHOULD THIN THROUGH THE MORNING...BUT NORTHERN AREAS MAY NEED TO BE EXTENDED A FEW HOURS. OTRW...WEAKER WARM AIR ADVECTION WL CARRY NMRS CONVECTION ACROSS WRN CWA EARLY THIS MRNG...HOWEVER FOCUS OF WAA REMAINS OVER NRN HALF OF WI EARLY. LOW LEVEL JET STRENGTHENS ONCE AGAIN AHEAD OF STRONG UPPER LOW OVER NORTHERN PLAINS LATER THIS MRNG AND AFTERNOON ACROSS NRN IL/SRN WI REGION. SFC LOW SLIGHTLY WWD POSITION AT 12Z COMPARED TO EARLIER RUNS...AND 00Z NAM CONTINUES TO ADJUST ITS TIMING AND POSITION TO MORE FAVORED GFS AND ECMWF. INCREASING SOUTH WINDS AHEAD OF SFC LOW WL ALLOW WARM FRONT OVER NRN IL TO MOVE NWD ACROSS PORTIONS OF SRN WI TODAY AS SURFACE OCCLUSION BEARS DOWN ON THE AREA. OCCLUSION MAKES SLOW EWD PROGRESS TODAY...AND LOOKS LIKE IT WILL EXIT ERN CWA AROUND 06Z. STRONGER LAYER Q-VECTOR CONVERGENCE SPREADS IN THIS AFTN AND TNGT WITH OCCLUSION AND UPPER LEVEL SHORT WAVE. MUCAPE CURRENTLY AROUND 500 J/KG EXPECTED TO INCREASE TO 1500-2000 J/KG LATER TODAY AHEAD OF OCCLUSION. NO PROBLEM WITH AVAILABLE SHEAR FAVORING MULTICELLS AND SUPERCELLS MODE. IF LOW CLOUDS CLEAR OUT IN TIME ACROSS PORTIONS OF THE CWA...SHEAR AND INSTABILITY SHOULD BE ENOUGH TO TRIGGER STRONG TO SEVERE CONVECTION. CAN NOT RULE OUT A TORNADO CONSIDERING STRENGTH OF FORCING. PWAT REMAINS OVER 200 PERCENT OF NORMAL...SO IF EXPECTED NORTH TO SOUTH LINE OF CONVECTION LINGERS OVER AREA...POTENTIAL FOR FLASH FLOODING. WARM CLOUD DEPTH PRIOR TO AFTN CONVECTION OVER 11K FEET. FORTUNATELY HEAVIEST RAINFALL OF THE PAST SEVERAL DAYS HAS BEEN MOSTLY WEST AND SOUTH OF CWA. WILL CONTINUE SMALLER THREAT FOR CONVECTION LATE TONIGHT IN ERN CWA DUE TO LINGERING LOW LEVEL JET IN THE AREA. SUNDAY - CONFIDENCE...MEDIUM SLOW MOVING NEARLY STACKED LOW PROGGD TO TRAVERSE FROM WESTERN IOWA INTO CNTRL IL THROUGH SUNDAY NIGHT. PLENTY OF DRY AIR WRAPPING AROUND THIS SYSTEM WITH DRY SLOT ACRS MUCH OF WI. 850 COLD ADVECTION FROM THE SOUTHWEST. SOME MODELS SHOW CLOSE TO ZERO CELSIUS TOWARDS THE IL BORDER BY LATER SUNDAY NIGHT. THE NAM MODEL IS THE ONLY MODEL TO DEVELOP SOME DEF ZONE PRECIP SUNDAY NIGHT WITH A BIT MORE 700 RH ON THE NORTHERN SIDE OF THE SYSTEM THAN THE OTHER MODELS. SURFACE TROUGH AXIS EXTENDS ACROSS NRN AND WRN WI SO GIVEN THE PROGGD PLACEMENT OF DRY RH AND QPF...WILL REMOVE POPS FOR SUNDAY BUT LEAVE THEM IN FOR SUNDAY NIGHT. MONDAY - CONFIDENCE...MEDIUM MODEL CONSENSUS IS TO MOVE LOW FROM CNTRL IL INTO NE IN. BROAD 850 MILLIBAR CIRCULATION BECOMES CLOSED ACROSS LWR MI DURING THE AFTERNOON. SURFACE/850 TROUGH EXTENDS FROM THE LWR MI LOW INTO CNTRL/SRN WI ENHANCING LOW LEVEL FORCING. IN ADDITION TO THE RIPPLES WRAPPING WEST AND SOUTHWEST AROUND THE PERIPHERY OF THE UPPER LOW CENTER. SO WILL HAVE CHANCE POPS FOR SHRA IN THIS PATTERN. THE 00Z ECMWF HAS THROWN A BIT OF A WRENCH INTO THINGS BY COMING IN WITH A MUCH MORE PROGRESSIVE SOLUTION HOWEVER GIVEN THE CURRENT LOCATION AND STRUCTURE OF THIS SYSTEM WOULD APPEAR THAT LEANING TOWARDS A SLOWER SOLUTION HAS MORE CREDENCE AT THIS POINT. WILL NOT JUMP ON THIS NEW ECMWF DEVELOPMENT YET ESP WITH THE NAM/GFS/GEM ALL SHOWING A SLOWER LOOK. TUESDAY - CONFIDENCE...MEDIUM LOW PLODS INTO THE EASTERN GREAT LAKES WITH CYCLONIC FLOW ON THE WESTERN SIDE STILL LINGERING INTO EASTERN WI. ALLBLEND HAS SOME SLIGHT POPS IN THE EAST AND FOR NOW THIS IS FINE. WITH THE FASTER 00Z ECMWF WAS TEMPTED TO PULL THIS POP BUT AFTER COORD WITH LOT/GRB WAS DECIDED TO LEAVE THIS AS IS FOR NOW AND STICK WITH THE CONSENSUS. APPEARS INFLUENCE OF THE UPPER CIRCULATION GETS FAR ENOUGH AWAY WITH SURFACE RIDGING BUILDING IN FOR THE AFTERNOON. WEDNESDAY THROUGH FRIDAY - CONFIDENCE...MEDIUM SURFACE/850 HIGH CENTERED OVER THE AREA ON WEDNESDAY. WITH A SHIFT TO THE EAST ON THURSDAY AND FRIDAY...THIS SETS UP A RETURN SOUTHERLY FLOW WHICH BRINGS MILDER 925 TEMPS INTO THE AREA. AVIATION/12Z TAFS/...AREAS OF DENSE FOG WILL GRADUALLY THIN THIS MORNING AS WINDS INCREASE AS WARM FRONT IN NRN IL ADVANCES NORTH. CIGS MAY EVEN INCREASE TO VFR FOR A TIME BEFORE NMRS CONVECTION SPREADS IN LATE MRNG AND AFTN. CONVECTION SHOULD END OVERNIGHT WRN AREAS AS OCCLUDED FRONT SLIDES EAST OF AREA. MARINE...WL CONTINUE DENSE FOG ADVY INTO THE AFTN AS WARM...MOIST AIR CONTINUES TO MOVE ACROSS COOLER NEAR SHORE WATERS OF LAKE MI. SCATTERED MORNING AND EARLY AFTN CONVECTION WL GIVE WAY TO A MORE WIDESPREAD PERIOD LATER THIS AFTN AND EVE. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...DENSE FOG ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR WIZ052-060. LM...DENSE FOG ADVISORY UNTIL 10 PM CDT THIS EVENING FOR LMZ643>646. && $$ UPDATE...MRC TODAY/TONIGHT AND AVIATION/MARINE...MBK SUNDAY THROUGH FRIDAY...COLLAR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1150 AM CDT SAT OCT 5 2013 .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 413 AM CDT SAT OCT 5 2013 MOST EFFORT THIS FORECAST SHIFT WAS PUT TOWARD GETTING THE NEXT 24 HOURS AS ACCURATE AS POSSIBLE. SCREAMING MESSAGE IS THE SLOWER EASTWARD PROGRESSION OF THE FRONT AND INSTABILITY...MAKING FOR A BIT HIGHER SEVERE WEATHER CHANCE IN WI TODAY. WATER VAPOR SHOWING THE MONSTER LOW THAT BROUGHT 25-45 INCHES OF SNOW TO SD OVER CENTRAL SD AT 08Z AND NEARLY STATIONARY. OCCLUDED FRONT CURRENTLY POSITIONED FROM KRWF TO KCCY...WHERE THE TRIPLE POINT IS LOCATED. THE WARM FRONT EXTENDS EAST FROM NEAR KCCY TO THE DELLS IN WI...WITH THE SURFACE COLD FRONT RUNNING SOUTH FROM KCCY. THIS WARM FRONT IS THE LEADING EDGE OF THE HIGHER DEWPOINT AIR...MIDDLE 60S...AND THE ENERGY FOR THIS AFTERNOONS STORMS. THE OVERNIGHT CONVECTION HAS NOW PASSED OFF TO THE EAST...AND WITH IT THE FLASH FLOOD THREAT. EVALUATING THE 04.00Z MODEL GUIDANCE...THE TREND IS SLOWER WITH THE NORTHEAST PROGRESSION OF THE OCCLUDED/COLD FRONT. THIS ALLOWS MORE OF THE FORECAST AREA IN WI TO BE PRE-FRONTAL AND IN THE WARM SECTOR FOR A HIGHER PROBABILITY OF SEVERE WEATHER. AS THE DAY PROGRESSES...QVECTOR CONVERGENCE WILL INCREASE AS A SHORTWAVE TROUGH IN COLORADO ROTATES AROUND THE LARGER SD TROUGH AND BEGINS ITS EASTWARD PROGRESSION. AS THE FORCING BEGINS TO INCREASE...NEAR/POST FRONTAL SHOWERS WILL LIKELY DEVELOP MUCH LIKE SEEN ON RADAR ALONG I-35 EARLY THIS MORNING. ALSO...BETTER UPPER LEVEL FORCING WILL BEGIN TO WORK TOWARD THE WARM SECTOR AND WORK WITH 0-2KM THETA-E CONVERGENCE ALONG THE FRONT. INSTABILITY IN THE WARM SECTOR WILL HIGHLY DEPEND ON THE EXTENT OF THE SHOWERS AND CLOUDS OVER WI...HOWEVER BECAUSE THE DEWPOINTS ARE ALREADY MIDDLE 60S...AT LEAST MARGINAL INSTABILITY WILL BE PRESENT BY 18Z. MUCAPES AROUND 1000-1500 J/KG LOOK TO BE A GOOD ESTIMATE ON AFTERNOON CAPE...POSSIBLY HIGHER WITH MORE CLOUD BREAKS. WIND SHEAR LOOKS TO INCREASE TODAY BUT RIGHT ON THE COLD/OCCLUDED FRONTAL BOUNDARY...TO MAKE IT A MARGINAL SUPERCELL DAY WITH MULTI-CELLS ALSO PRESENT. THE 05.06Z NAM AND 05.07Z RAP BOTH SUGGEST NEAR 40 KTS OF 0-6KM SHEAR...CERTAINLY ENOUGH FOR SUPERCELLS. THE 05.07Z RAP MIXES ALL THE PRE-FRONTAL SURFACE WINDS TO SOUTHERLY. THE 05.06Z NAM AND LATEST HRRR RUNS ARE VERY AGREEABLE THAT THE WARM FRONT WILL SHIFT NORTH TO ABOUT BLACK RIVER FALLS WI TODAY...VERY CLOSE TO THE SPC DAY 1 NORTHERN EXTENT OF THE SLIGHT RISK. EASTERLY FLOW IS FOUND NORTH OF THE WARM FRONT...WHICH EXTENDS TO THE EAST TOWARD KGRB...SO A GOOD CONVERGENT BOUNDARY. WHILE TORNADO PROBABILITIES DONT LOOK HIGH...THE TRIPLE POINT AREA AND ALONG THAT WARM FRONT THIS AFTERNOON WILL BE A FOCAL POINT. OTHERWISE...DAMAGING WIND SEGMENTS OR LARGE HAIL ARE THE MAIN THREATS FROM THE STORMS IN WI. NORTH OF THE WARM FRONT...LOW-LEVEL INVERTED CONDITIONS AND ELEVATED STORMS ARE FAVORED...HEAVY RAIN IS THE MAIN THREAT...WITH AN ISOLATED HAIL STORM POSSIBLE. THE FRONT SHOULD SHIFT EAST OF THE FORECAST AREA BY EARLY EVENING WITH STRONG DEWPOINT DECREASES. THUS...THE MAIN SEVERE WEATHER THREAT LOOKS TO BE ABOUT 1 PM TO 5 PM. BY TONIGHT...THE NE AND EASTERNMOST FORECAST AREA MAY STILL HAVE SOME RAIN REMAINING. HAVE SLOWED THAT SLIGHTLY FROM THE PREVIOUS FORECAST. A DECREASING TREND OCCURS THROUGH THE EVENING AS WEATHER SHIFTS EAST. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 413 AM CDT SAT OCT 5 2013 THE LATEST MODEL CONSENSUS IS TO NOW KEEP THE DEFORMATION ASSOCIATED WITH THE CYCLONIC MOIST FLOW WRAPPING AROUND THE LOW TO THE WEST-NORTHWEST ON SATURDAY. THIS IS HIGHLY DEPENDENT ON THE TRACK OF THE LOW WHICH IS A BIT FURTHER SOUTH IN THE LATEST GUIDANCE. IN ANY CASE...CHANGES WERE MADE TO SUNDAY TO TRY AND DRY IT OUT WITH THE RAIN SHOWERS JUST WEST OF THE AREA. ALTHOUGH THE CONSENSUS OF THE MODELS IS TO BRING THAT BAND INTO THE FORECAST AREA FOR MONDAY NOW...THE LATEST 05.00Z ECMWF IS MUCH MORE PROGRESSIVE AND RAPIDLY SHIFTS THE SHOWERS EAST. HAVE A SMALL CHANCE OF SHOWERS TO ADDRESS THAT SITUATION. THE REMAINDER OF THE PERIOD IS DOMINATED BY DRY WEATHER UNDER && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON) ISSUED AT 1150 AM CDT SAT OCT 5 2013 FRONTAL BOUNDARY WILL CONTINUE TO ROTATE NORTHEAST ACROSS THE REGION THIS AFTERNOON. ITS ALREADY CLEARED KRST...AND WILL DO SO AT KLSE BY MID-AFTERNOON. COULD BE A BRIEF SWITCH TO WESTERLY WINDS FOR AN HOUR OR TWO...THEN SHIFT BACK TO MORE SOUTH-SOUTHWEST. AN UPPER LEVEL SHORTWAVE MOVING IN FROM THE SOUTHWEST WILL WORK ON THE FRONT TO SPAWN SCT SHRA/TS NEAR THE SFC FRONT...AND THIS ACTIVITY COULD IMPACT THE TAF SITES FOR A FEW HOURS THIS AFTERNOON. SKIES SHOULD CLEAR THIS EVENING AS DRY AIR WRAPS INTO THE STORM SYSTEM...PER LATEST SATELLITE IMAGERY. MASS OF MVFR/IFR CIGS ASSOCIATED WITH THE MAIN SFC LOW WITH THE SYSTEM...CURRENTLY ACROSS SD. THE LOW WILL MOVE EAST/NORTHEAST TONIGHT...BRINGING THE CLOUD SHIELD IN NEAR 12Z. NUMERICAL GUIDANCE SUGGEST ONLY VFR CIGS BY THAT TIME...BUT HARD TO ARGUE WITH SFC OBS/SATELLITE...PLUS RH FIELDS SUPPORT LOWER CIGS. WILL BRING IN SOME MVFR CIGS FOR SUN MORNING. ANOTHER FORECAST CONSIDERATION IS THE POTENTIAL FOR FOG...ESPECIALLY IN THE RIVER VALLEYS. WITH EXPECTED CLEARING TONIGHT...THE SFC PRESSURE GRADIENT BECOMING BAGGY - THUS LIGHT WINDS...AND RECENT RAINS TO MOISTEN THE BOUNDARY LAYER...IT COULD BE FAVORABLE FOR SUB 1SM AT KLSE. HOW LONG IT STAYS CLEAR WILL PROBABLY BE THE BIGGEST FACTOR...AND A LOT OF UNCERTAINTY HERE. WILL ADD BCFG FOR NOW. && .HYDROLOGY... ISSUED AT 413 AM CDT SAT OCT 5 2013 CONCERNING THE FLASH FLOOD WATCH...WITH CURRENT CONVECTION EAST OF THE AREA...MAIN THREAT HAS DIMINISHED. AS AFTERNOON CONVECTION INCREASES...IT SHOULD BE AFFECTING AREAS THAT HAVE HAD LESS RAIN OVERALL THAN THOSE WEST OF THE MISS RIVER. AREAS EAST OF THE MISS RIVER CAN TAKE ANOTHER 1-2 INCHES...ESPECIALLY SWRN WI. THERE IS A SMALL PROBABILITY OF LOCALIZED FLASH FLOODING TODAY IN THE CENTRAL WI CORRIDOR IN THE PRE-FRONTAL AIR MASS WHICH WILL STILL HAVE 1.25 TO 1.75 INCH PRECIPITABLE WATER VALUES. RAIN RATES ARE EXPECTED TO BE HIGH...PROBABLY 2 TO 3 INCH PER HOUR SHOULD CAPE DEVELOP AS FORECAST. THE SLOW MOVEMENT OF THE FRONT DOES GIVE SOME CONCERN FOR FLOODING SO WILL ISSUE ANOTHER HYDROLOGICAL DISCUSSION FOR THAT AREA AND CANCEL THE FLASH FLOOD WATCH. THERE ARE SOME RIVER RESPONSES CURRENTLY OCCURRING. MONITORING THE ROOT RIVER BASIN AND THE UPPER IOWA RIVERS BOTH HAVE RESPONSES. ALSO THE WHITEWATER RIVER MIDDLE FORK THAT RUNS THROUGH WHITEWATER STATE PARK IS RISING. AT THIS TIME THESE WILL APPROACH FLOOD STAGE BUT IT IS BELIEVED THEY WILL NOT REACH IT. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT TERM...BAUMGARDT LONG TERM....BAUMGARDT HYDROLOGY....BAUMGARDT AVIATION.....RIECK