AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 458 AM MDT WED SEP 20 2006 .SHORT TERM... (TODAY AND TONIGHT) ...VERY ACTIVE WEATHER PATTERN BEGINS TODAY... ...BREEZY TO WINDY CONDITIONS OVER THE NEXT 24 HOURS... ...POSSIBLE BRIEF CRITICAL FIRE WEATHER CONDITIONS SOUTHEAST CO... ...MINOR ACCUMULATING SNOW GENERALLY ABOVE 8K FT MSL... CURRENTLY...COLLECTION OF SATELLITE IMAGERY AND RUC MODEL UPPER AIR ANALYSES SHOWING CLOSED LOW OVER GREAT BASIN COMING OUT OF PACIFIC NORTHWEST WITH ACTUALLY TWO LOWS RIGHT NOW...ONE OVER EASTERN OR AND ANOTHER OVER NV. ASSOCIATED MOISTURE AND CLOUD MASS JUST TO THE EAST OF THE SYSTEM. SYSTEM HAD PLENTY OF LIGHTNING IN IT YESTERDAY DURING THE AFTERNOON AND EVENING PER POST LIGHTNING DATA ANALYSIS. PARENT UPPER LEVEL JET STREAK STILL ON THE SYSTEMS BACKSIDE. SECONDARY UPPER LEVEL JET STREAK MOVING OUT OF THE DESERT SOUTHWEST INTO SOUTHERN CO. MOUNTAIN TOP WIND FLOW HAS INCREASED TO 30-40KTS PER RUC MODEL DATA. HIGH TERRAIN SURFACE SENSORS SHOWING GUSTS OF 20-30KTS. BLACK MOUNTAIN RAWS AT THE LEE OF THE NORTHERN SANGRE DE CRISTO MOUNTAINS ALREADY GUSTING TO AROUND 35KTS. EASTERN MOUNTAIN LEE SIDE(6.5-9K FT MSL) NOCTURNAL INVERSION HOLDING STRONG WITH TEMPERATURES STILL IN THE 50S TO LOWER 60S EARLY THIS MORNING... WHILE LOWER ELEVATIONS IN THE ADJACENT PLAINS HAVE COOLED INTO THE UPPER 30S TO 40S. TODAY...WRF AND GFS ARE NOT TOO FAR OFF FROM EACH OTHER OVER THE NEXT 12 HOURS. 100-120KT UPPER LEVEL JET STREAM MOVES OVER SOUTHERN CO AND DEEP SOUTHWESTERLY FLOW INCREASES IN THE LOWER AND MIDLEVELS. BREEZY TO WINDY CONDITIONS WILL BE LIKELY BY THIS AFTERNOON DUE TO DEEP MIXING AND MIDLEVEL INSTABILITIES...H7-H5...ARE PROGGED TO BE 8-9.5 C/KM OVER THE PLAINS AND 7-8 C/KM. SURFACE CYCLOGENESIS ALWAYS MAKES IT TOUGH IN EASTERN CO. WRF HINTS THE SURFACE LOW FORMING AROUND LIMON WITH LEE SIDE TROUGHING SOUTHWARD THIS AFTERNOON. TEMPERATURES SHOULD WARM NICELY IN SOUTHEAST CO. MINIMUM HUMIDITY VALUES APPROACH 15 PERCENT WITH HAINES INDICES AROUND 5. THIS COMBINED WITH BREEZY TO WINDY CONDITIONS COULD BRIEFLY CREATE CRITICAL FIRE WEATHER CONDITION ALONG I-25 CORRIDOR AND SOUTHEAST CO PLAINS THIS AFTERNOON AND EARLY EVENING. WILL NOT PLAN TO ISSUE ANY HEADLINES SINCE THE LARGE FUEL MOISTURES ARE FAIRLY "WET" FROM THE WET JUN-AUG. THE FINER FUELS...1HR-10HR... ARE LIKELY CURING/DRYING... BUT IT IS SUCH A BRIEF EVENT FOR ALL CONDITIONS TO BE JUXTAPOSED. WRF CONTINUES TO DEVELOP QPF OVER THE CONTINENTAL DIVIDE AND A LITTLE FURTHER EAST THIS AFTERNOON. GIVEN THE MIDLEVEL INSTABILITY...THUNDER LOOKS DOABLE. ALSO...SNOW...SLEET...OR GRAUPEL WILL BE LIKELY ON THE MOUNTAINS TOPS AND HAVE ADJUSTED GRIDS ACCORDINGLY. TONIGHT...THINGS START TO GET VERY INTERESTING AND WILL SIGNIFICANTLY DEPEND ON THE SYSTEMS EVOLUTION AND TRACK. WRF AND GFS HAVE TRENDED TOWARDS A MORE SOUTHERN TRACK AND DIRECTLY OVER SOUTHERN CO TONIGHT. AS THE LOW PRESSURE SYSTEM MOVES INTO CO DURING THE EVENING...A SIGNIFICANT NORTH-SOUTH LOW AND MIDDLE LEVEL COLD FRONT DRIVES ACROSS SOUTHEAST CO...BORA EVENT. ALSO...H7-H6 AND H6-H5 POSITIVE FRONTOGENETICAL FORCING...IMPLIED ASCENT...ASSOCIATED WITH FRONTAL BOUNDARY. FIRST POTENTIAL FOR PRECIPITATION ACROSS SOUTHEAST CO WILL BE WITH THAT COLD FRONT. MIGHT SEE A BRIEF CHANCE TO MIXED DOWN SOME 30-45KT WINDS TO THE SURFACE. MEANWHILE...THE COMBINATION OF MOIST OROGRAPHICS AND SYNOPTIC SCALE ASCENT FROM THE LOW SHOULD BE GENERATING A DECENT CHANCE FOR PRECIPITATION ACROSS THE CONTINENTAL DIVIDE WHERE H7 TEMPERATURES WILL BE -2C TO -4C AND SNOW FALLING GENERALLY ABOVE 8K FT MSL IN THE COLLEGIATE AND MOSQUITO MOUNTAIN RANGES. THE VERTICALLY STACKED LOW MOVES INTO SOUTHEAST CO/SOUTHWEST KS BETWEEN 06Z-12Z/21 AS THE DEFORMATION ZONE CLOUD AND PRECIPITATION SHIELD DEVELOPS OVER EASTERN CO. ALWAYS A TOUGH CALL WITH THESE EVENT SINCE THE DEFORMATION ZONE PRECIPITATION IS RELATIVELY NARROW. WRF H7-H6 AND H6-H5 SHOWING NICE TROWAL FORMATION FROM NORTHEASTERN CO TOWARDS THE PALMER DIVIDE AND SOUTHEAST CO PLAINS AFTER MIDNIGHT. WILL TWEAK POPS UP IN THESE AREAS. MIGHT ACTUALLY SEE SOME SNOWFLAKES ALONG THE PALMER DIVIDES HIGHER ELEVATIONS AS WET BULB ZERO HEIGHT AROUND 8.5K FT MSL. IF THE SYNOPTIC SCALE LIFT IS STRONG ENOUGH...DIABATIC COOLING COULD BRING THE FIRST SNOWFALL TO THE PALMER DIVIDE IN LATE 2006. STRONG PRESSURE GRADIENT WILL ALSO OCCUR IN EASTERN CO WITH H7 50-60KTS SHOWING UP OVER THE PALMER DIVIDE INTO SOUTHEAST CO. MEANWHILE... MOIST WEST-NORTHWEST FLOW ALOFT IS BRING SNOWFALL TO THE COLLEGIATES AND MOSQUITO MOUNTAIN RANGES WHERE 3 TO 10 INCHES MAY FALL WITH BLOWING SNOW POTENTIAL. SINCE THIS IS CLOSE TO THE FIRST EVENT OF THE SEASON WILL GO WITH SNOW AND BLOWING SNOW ADVISORY FOR ZONES 060 AND 058. CLIMAX TYPICALLY GET SNOW IN THESE PATTERNS. LEADVILLE MIGHT GET A COUPLE OF INCHES...TOO. METZE .LONG TERM... (THURSDAY THROUGH NEXT TUESDAY) RATHER ACTIVE METEOROLOGICAL PATTERN CONTINUES FROM THURSDAY INTO SATURDAY AS INITIAL UPPER SYSTEM EXITS INTO KANSAS THURSDAY AFTERNOON AND THEN TRAILING UPPER SYSTEM PUSHES ACROSS NORTHERN COLORADO FRIDAY WHICH IS FOLLOWED BY A MORE TRANQUIL NORTHWEST TO ZONAL FLOW ALOFT PATTERN FROM SATURDAY NIGHT INTO NEXT TUESDAY. AT THE START OF THE LONG TERM...EXPECT GUSTY WINDS AND PRECIPITATION TO BE AN ISSUE...ESPECIALLY THURSDAY MORNING AS UPPER LOW DEEPENS OVER WESTERN KANSAS. PRECIPITATION AMOUNTS AND COVERAGE AS WELL AS WINDS SHOULD DECREASE AS THURSDAY AFTERNOON PROGRESSES. ANOTHER ROUND OF GUSTY WINDS AND MOUNTAIN SNOWS AND LOWER ELEVATION PRECIPITATION SHOULD BE NOTED FROM FRIDAY INTO SATURDAY AS SECONDARY TRAILING SYSTEM MOVES ACROSS NORTHERN COLORADO. EXPECT BEST POTENTIAL FOR ACCUMULATING SNOW TO BE OVER PORTIONS OF THE CENTRAL MOUNTAINS FROM LATE THURSDAY AFTERNOON INTO FRIDAY MORNING WHERE SEVERAL ADDITIONAL INCHES OF SNOW WILL BE POSSIBLE...(POSSIBLY WARRANTING ANOTHER SNOW/BLOWING SNOW ADVISORY THIS AREA ONCE AGAIN). ALSO...WOULD NOT SURPRISE ME TO SEE SOME LIGHT ACCUMULATING SNOW OVER HIGHER SECTIONS OF ZONE 84(AREAS SUCH AS MONUMENT AND BLACK FOREST) AS WELL AS SECTIONS OF TELLER COUNTY AND HIGHER ELEVATIONS OF THE WET MOUNTAINS FROM FRIDAY NIGHT INTO SATURDAY MORNING. HAVE ATTEMPTED TO DEPICT THESE PARAMETERS IN JUST RELEASED GRIDS/ZONES. AS TRAILING SYSTEM PULLS EAST OF REGION SUNDAY...EXPECT DRYING AND WARMING CONDITIONS TO SET IN OVER CWFA. SPEAKING OF TEMPERATURES...PROJECT THAT COOLEST TEMPERATURES OF THE LONG TERM TO OCCUR SATURDAY AND SUNDAY WITH WARMEST TEMPERATURES EXPECTED BY NEXT TUESDAY. THANKS SURROUNDING OFFICES FOR COORDINATION/COLLABORATION. && .PUB WATCHES/WARNINGS/ADVISORIES... SNOW AND BLOWING SNOW ADVISORY FROM 6 PM THIS EVENING TO 12 PM MDT THURSDAY FOR COZ058-COZ060. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 339 PM CDT WED SEP 20 2006 .DISCUSSION... DAYS 1-2... PRECIP AND WINDS WITH THIS INCOMING SYSTEM WILL BE THE MAIN FORECAST CONCERN FOR THE SHORT TERM. 12Z MAPS CONTINUE TO SHOW A VERY VIGOROUS UPPER LOW DIGGING INTO THE FOUR CORNERS REGION, WITH A SMALL AREA OF -24 C COLD POOL AND 110 METER HEIGHT FALLS. THE WV LOOP HAS THE SYSTEM CONTINUING TO DIG SOUTH, AND IT MAY BE A BIT SLOWER ON EJECTING OUT INTO THE PLAINS TONIGHT. THE SFC LOW WILL CONTINUE TO DEEPEN OVER THE WESTERN PLAINS, AND WE SHOULD GET VERY GOOD SOUTHERLY FLOW BRINGING MOISTURE NORTHWARD. HIGHEST DEWPOINTS IN THE 60S ARE STILL DOWN FAIRLY SOUTH OVER TX, BUT WE ARE ALREADY HAVE A NARROW TONGUE OF MID 50S, AND WITH THE DRYLINE RETREATING WE SHOULD GET MID TO UPPER 50S, WHICH SHOULD BE ENOUGH TO GET SOMETHING STARTED IN OUR WEST. THE RUC HAS US GETTING DRYSLOTTED TONIGHT, BUT THINK THE NAM IS A BIT BETTER ON THIS WITH WINDS BACKING AND MOISTURE COMING BACK WEST. THINK THAT WE WILL GET SOME SCATTERED THUNDERSTORMS DEVELOPING IN OUR SOUTHWEST SOMETIME AROUND MIDNIGHT OR AFTER TONIGHT. SHEAR WILL BE VERY IMPRESSIVE, ALTHOUGH INSTABILITY WILL BE NOT AS GREAT, SOMEWHERE AROUND 1000 J/KG AT MOST. THERE WILL BE A BRIEF PERIOD WITH THE POTENTIAL FOR SEVERE WINDS AND HAIL EARLY, BUT THAT SHOULD END AS THE BOUNDARY LAYER COOLS AND CONVECTION BECOMES MORE ELEVATED. THE THUNDERSTORMS SHOULD CONTINUE TO MOVE INTO THE EASTERN CWA TOWARDS MORNING, WITH RAIN AND EVEN SOME ISOLATED THUNDERSTORMS WRAPPING AROUND THE LOW TOMORROW AND AFFECTING OUR NORTHERN COUNTIES. ALONG WITH THE CHANCE FOR PRECIP THROUGH TONIGHT AND TOMORROW, WINDS WILL ALSO BE A CONCERN. THE SFC LOW WILL DEEPEN RAPIDLY TONIGHT TO AROUND 990MB BY TOMORROW MORNING. MODELS ALL HAVE STRONG WINDS AT 850MB, WITH 35 TO EVEN 60KTS OVER OUR SOUTHEAST BY 12Z. THE GFS AND NAM ARE NOT THAT IMPRESSIVE WITH WINDS, BUT THE RUC HAS ADVISORY CRITERIA OVER OUR SOUTHEAST TONIGHT, AND PTT IS ALREADY BLOWING. IN ADDITION, AS THE LOW MOVES EAST TOMORROW THERE WILL BE STRONG NORTHWESTERLY WINDS ON THE BACKSIDE OF THE LOW, AND THERE SHOULD BE SOME DECENT MOMENTUM TRANSFER WITH CAA. BEST WINDS WILL BE IN THE SOUTHEAST TONIGHT AND WEST TOMORROW, BUT IN THE INTEREST OF BEING SIMPLE HAVE GONE WITH AN ADVISORY FOR THE WHOLE CWA AND WILL BE SPECIFIC IN THE WORDING. LOWS TONIGHT SHOULD STAY FAIRLY MILD WITH PLENTY OF WIND ALONG WITH CLOUDS AND PRECIP. TOMORROW WE SHOULD GET SOME COOLER TEMPS FILTERING IN AND THE NORTH AND EAST SHOULD STAY PRETTY CLOUDY. HOWEVER, THE SOUTH MAY SEE SOME SUN DUE TO THE DRY AIR INTRUSION AND WE WILL HAVE DOWNSLOPE FLOW. WENT MAINLY IN THE UPPER 60S TO LOW 70S. CONDITIONS WILL QUIET DOWN THURSDAY NIGHT AS THE FIRST UPPER LOW MOVES EAST, AHEAD OF THE NEXT WAVE DIGGING INTO THE WEST. WINDS WILL BE LOWER, AND LOWS THURS NIGHT WILL BE SLIGHTLY COOLER. THE NAM BRINGS THE NEXT WAVE OUT INTO THE PLAINS BY FRIDAY EVENING, BUT THINK THAT THIS IS A BIT FAST, SO LEANED TOWARDS THE SLOWER GFS/UKMET AND KEPT ONLY LOW POPS IN THE NORTHWEST. DAYS 3-7... FORECAST CHALLENGES INCLUDE THE MAGNITUDE OF OUR SECOND STORM SYSTEM AND TEMPERATURES. TROPICAL CONVECTIVE FORCING IS CURRENTLY CENTERED ~10N/140E WHILE EXTENDING FROM THE ARABIAN SEA TO THE SOUTH PACIFIC ISLANDS. ABOUT A WEEK AGO A CONSOLIDATION OF EASTWARD AND WESTWARD PROPAGATING EQUATORIALLY TRAPPED CONVECTIVELY COUPLED MODES OCCURRED AROUND 10-15N/120E. WE ARE STILL EXPERIENCING THE RAMIFICATIONS FROM THIS EVENT AS I TYPE. THE LATTER LED TO STRONGLY POLEWARD DIRECTED DIVERGENT OUTFLOW WHICH INTERACTED WITH A BAROCLINIC WAVE PACKET MOVING EAST ACROSS NORTHERN ASIA. THE RESULT WAS AN ANOMALOUSLY STRONG NORTH PACIFIC JET (AT LEAST 20-30 M/S ANOMALIES) THAT SUBSEQUENTLY AMPLIFIED. THE PHASE WAS DETERMINED BY THE LOCATION OF THE TROPICAL CONVECTIVE FORCING INTERACTING OTHER DYNAMICAL PROCESSES ACROSS THE NORTHERN HEMISPHERE EXTRATROPICS. CURRENTLY GSDM STAGE 1 BEST DESCRIBES THE GLOBAL CIRCULATION, WHICH INCREASES THE ODDS FOR TROUGHS TO DIG INTO THE WESTERN USA. IN THE LONGER TERM (WEEKS 2-3), I SUSPECT THE TROPICAL FORCING WILL SHIFT EAST TOWARD THE WARM SSTS AROUND DATE LINE, LEADING TO AN EASTWARD SHIFT OF OUR CURRENT REGIME. I CAN ALREADY SEE EVIDENCE OF THIS FROM CURRENT FULL DISK SATELLITE IMAGERY. ALL OF THE ABOVE HAD LED TO THE CURRENTLY DEVELOPING MID/UPPER TROPOSPHERIC TROUGH ACROSS THE CENTRAL ROCKIES. PER THE NCEP GFS ENSEMBLE MEAN AVAILABLE FROM THE ESRL/PSD WEB SITE, ANOMALIES ~5-6 STANDARD DEVIATIONS BELOW CLIMATOLOGY IN THE MSLP FIELD ARE EXPECTED FOR THE SURFACE RESPONSE AS IT MOVES INTO MY CWA THURSDAY (VT 1200 UTC 9/21). I HAVE TO BELIEVE THIS NORMALIZATION IS DERIVED FROM THE 1971-2000 CLIMATOLOGY, WHICH WOULD REFLECT A TREND OF LESS FREQUENT INTENSE BAROCLINIC STORMS ON THE PLAINS DURING "RECENT YEARS". IN ANY CASE, THERE IS OFTEN A SECOND STORM SYSTEM TO DEAL WITH IN THESE GSDM STAGE 1 SITUATIONS, AND SUCH IS TRUE FOR FRIDAY NIGHT INTO SATURDAY. BOTH HUMANS AND MODELS HAVE STRUGGLED WITH THE DETAILS OF THIS SECOND SYSTEM (WHICH IS TYPICAL), AND FORTUNATELY WE HAVE STARTED TO GET BETTER MODEL AGREEMENT DURING THE LAST DAY OR SO (AS NOTED BY PREVIOUS SHIFT). THERE IS THE GENERAL NOTION FOR THE SECOND TROUGH TO DIG INTO THE SOUTHERN ROCKIES BY AROUND FRIDAY NIGHT, THEN EJECT TOWARD THE EAST AND NORTHEAST (WITHIN A NE-SW TILTED TROUGH; CONSISTENT WITH AAM TRANSPORT CONSIDERATIONS NOT DISCUSSED HERE). THE SURFACE RESPONSE WILL TRACK TO THE SOUTH OF MY CWA. MOISTURE TRANSPORT INTO THIS STORM SYSTEM WILL NOT BE A PROBLEM. WHILE THE MOST SIGNIFICANT RAINFALL WILL BE WELL TO MY SOUTHEAST, THERE WILL BE A SECONDARY REGION FORCED BY JET STREAK AND FRONTAL SCALE DYNAMICS. THE BEST OPPORTUNITY FOR THE LATTER WILL BE ACROSS MY NORTHERN CWA. I AGREE WITH THE PREVIOUS SHIFT THERE COULD BE ENOUGH ELEVATED INSTABILITY FOR SOME THUNDERSTORMS. I RAISED POPS TO CHANCE CATEGORY CWA WIDE AFTER 0600 UTC 9/23, STARTING ACROSS THE NORTHWESTERN COUNTIES FRIDAY EVENING AND LEAVING THE HIGHEST PROBABILITIES ACROSS THE NORTH DURING THE EVENT. I WENT FOR MOSTLY A LIGHT RAIN SITUATION WITH ISOLATED THUNDERSTORMS FRIDAY NIGHT, ENDING FROM THE SOUTHWEST ON SATURDAY. I DID NOT CHANGE TEMPERATURES MUCH FRIDAY NIGHT AND SATURDAY FROM EXISTING GRIDS. I DID LOWER MAXES A COUPLE DEGREES FOR SATURDAY. THE AIRMASS SOURCE IS FROM THE NORTH PACIFIC, AND SATURDAYS HIGHS WILL DEPEND ON CLOUD COVER. AFTER SATURDAY, THE WEATHER SHOULD BE DRY WITH A WARMING TREND BEGINNING ON MONDAY (WITH NICE DOWNSLOPE FLOW). I THINK THE COOLEST MORNING WILL BE SUNDAY WITH AT LEAST LOW-MID 40S FOR MINIMUMS. I DID RAISE MAXES A FEW DEGREES TO WELL INTO THE 80S FOR TUESDAY AHEAD OF THE NEXT COLD FRONT LIKELY TO MOVE SOUTHWARD FROM CANADA. MY THOUGHTS IS FOR THIS BOUNDARY TO MOVE THROUGH MY CWA SOMETIME THE MIDDLE OF NEXT WEEK. THE BEST DYNAMICS SHOULD BE NORTHEAST OF MY CWA AND MOISTURE LOOKS TO BE LACKING. I DID LOWER MAXIMUMS ON WEDNESDAY TO SUGGEST SOME COOLING. WITHOUT ELABORATING, I THINK THE MODELS ARE CORRECT IN SHIFTING THE REGIME EASTWARD LEADING TO A RIDGE ALONG THE WEST COAST AND A TROUGH TO OUR EAST, AT LEAST FOR MUCH OF WEEK 2. THIS IDEA SUPPORTS A DRY COLD FRONTAL PASSAGE AROUND DAYS 6-7 AND THE DAYS 8-10 PREDICTION WILL READ NEAR NORMAL TEMPERATURES AND LITTLE OR NO RAINFALL. && .PRELIMINARY POINT TEMPS/POPS... DDC 56 72 50 72 / 70 50 20 0 GCK 56 69 47 69 / 60 70 20 10 EHA 55 74 45 71 / 50 30 10 10 LBL 57 75 48 73 / 50 30 10 0 HYS 56 68 48 69 / 80 80 30 10 P28 61 78 53 76 / 70 60 10 0 && .DDC WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 7 PM CDT /6 PM MDT/ THIS EVENING TO 7 PM CDT /6 PM MDT/ THURSDAY FOR KSZ030-KSZ031-KSZ043-KSZ044-KSZ045- KSZ046-KSZ061-KSZ062-KSZ063-KSZ064-KSZ065-KSZ066-KSZ074-KSZ075- KSZ076-KSZ077-KSZ078-KSZ079-KSZ080-KSZ081-KSZ084-KSZ085-KSZ086- KSZ087-KSZ088-KSZ089-KSZ090. && $$ FN26/23 ks AREA FORECAST DISCUSSION...UPDATE NATIONAL WEATHER SERVICE GOODLAND KS 1106 AM MDT WED SEP 20 2006 .DISCUSSION...JUST COMPLETED AN UPDATE. SURFACE LOW OVER SOUTHEAST COLORADO HAS STRENGTHENED THIS MORNING. MODELS PLAYING CATCHUP WITH THIS FEATURE. NAM AND RUC40 LOOK TO CATCH THIS THE BEST. NOT SURE HOW FAR NORTH WARM FRONT TO OUR SOUTH WILL PROGRESS. I AM THINKING NOT TOO MUCH MORE NORTH. AS A RESULT...THIS WILL KEEP AN UNFAVORABLE WIND DIRECTION OVER MOST OF THE FORECAST AREA...ESPECIALLY IN THE NORTH. SOUTHERN THIRD OF THE AREA SHOULD WARM UP THE BEST. SO LOWERED MAXES NEAR 3 DEGREES...ESPECIALLY OVER THE NORTH HALF TO THIRD. ALSO ADJUSTED WIND DIRECTION BASED ON REALITY COMBINED WITH RUC AND NAM. OTHERWISE...REST OF FORECAST LOOKS ON TRACK. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ BULLER ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 416 PM EDT WED SEP 20 2006 .SYNOPSIS... 19Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN UPPER TROUGH COVERING MUCH OF SE CANADA INTO THE EASTERN GREAT LAKES...AN UPPER RIDGE OVER THE PLAINS OF NORTH AMERICA...AND UPPER TROUGHS OVER THE FOUR CORNERS REGION AND DROPPING INTO SW BRITISH COLUMBIA. WITHIN THE EASTERN GREAT LAKES TROUGH...A SHRTWV WAS PRESENT NEAR PICKLE LAKE ONTARIO. THIS SHRTWV CAN BE SEEN ON VISIBLE SATELLITE IMAGES. CANADIAN RADAR IMAGERY ALSO SHOWS SOME SHOWERS TO THE EAST AND ALONG THE TAIL END OF THE WAVE. SOME OF THESE SHOWERS ARE BEING SUPPORTED BY DIURNAL HEATING...NOTED BY THE CELLULAR APPEARANCE. OTHER CELLULAR TYPE CLOUDS AND LAKE EFFECT CLOUDS ARE PRESENT OVER UPPER MICHIGAN...THOUGH THOSE IN WESTERN LAKE SUPERIOR AND WESTERN UPPER MICHIGAN HAVE BEEN DISSIPATING DUE TO WARM ADVECTION OCCURRING AHEAD OF THE SHRTWV. AN UPPER AIR OBSERVATION AT 12Z OF 3C AT 850MB IN DULUTH COMPARED TO -1C AT GRB AND APX WITH WNW FLOW ON ALL THREE SITES INDICATES THE WARM ADVECTION. SOME LAKE EFFECT SHOWERS PERSIST ACROSS THE EASTERN SECTION OF THE CWA GIVEN THE COLD TEMPERATURES NOTED. AT THE SURFACE...A LOW PRESSURE TROUGH CAN BE SEEN OVER NORTHERN ONTARIO ASSOCIATED WITH THE PICKLE LAKE ONTARIO SHRTWV. A RIDGE OF HIGH PRESSURE COVERED MUCH OF THE MISSISSIPPI VALLEY WHILE LOW PRESSURE IS DEVELOPING OVER EASTERN COLORADO EAST OF THE NEXT UPPER LEVEL TROUGH IN UTAH. ANOTHER NOTE...THE AIRMASS REMAINS RELATIVELY DRY WITH DEWPOINTS RIGHT NOW MAINLY IN THE MID 30S ACROSS THE WEST HALF OF UPPER MICHIGAN AND RUC ANALYSIS OF PRECIPITABLE WATER AROUND 0.40 INCH. .SHORT TERM (TONIGHT AND THURSDAY)... THE UPPER LEVEL TROUGH OVER THE EASTERN GREAT LAKES INTO SE CANADA IS PROGGED TO CONTINUE LIFTING TO THE NE THROUGH THE PERIOD DUE TO THE TROUGHS OVER THE WESTERN HALF OF NORTH AMERICA PUSHING THE PLAINS RIDGE EASTWARD. AS THIS OCCURS...THE SHRTWV OVER NORTHERN ONTARIO WILL MOVE QUICKLY SOUTHEASTWARD ACROSS EASTERN LAKE SUPERIOR TONIGHT...ALONG WITH ITS ASSOCIATED SURFACE TROUGH. ISENTROPIC LIFT SEEN ON THE NAM\S 290K SURFACE...IN CONJUNCTION WITH SOME DPVA ASSOCIATED WITH THE SHRTWV...SHOULD CONTINUE TO ALLOW THE SHOWERS ON THE EAST SIDE OF THE SHRTWV TO DROP SE ONTO LAKE SUPERIOR TONIGHT... POSSIBLY GRAZING THE KEWEENAW PENINSULA AND LAKE SUPERIOR SHORELINE LOCATIONS EAST OF MARQUETTE. THIS IS IN AGREEMENT WITH NAM AND RUC QPF FIELDS. THEREFORE HAVE ADDED SOME SCATTERED SHOWERS TO THE FORECAST. FOR THE REST OF THE CWA...WINDS ARE PROGGED TO DECREASE TO CALM AS THE HIGH PRESSURE RIDGE BEGINS BUILDING INTO THE CWA. WITH THE CURRENT DIURNAL BASED STRATOCUMULUS EXPECTED TO DISSIPATE AND THE LOW DEWPOINTS/PRECIPITABLE WATER...CONDITIONS ARE FAVORABLE TO GET COLD AGAIN TONIGHT. MAV COOP GUIDANCE SUGGESTS MIN TEMPERATURES GETTING BACK DOWN INTO THE UPPER 20S FOR SOME OF THE COLD SPOTS...AND HAVE WENT WITH THIS IDEA IN THE FORECAST. THEREFORE HAVE ISSUED FREEZE WARNINGS FOR MUCH OF THE CWA...EXCLUDING THE KEWEENAW AND EASTERN CWA WHICH WILL BE AFFECTED BY CLOUD COVER AND MORE WIND ASSOCIATED WITH THE SHRTWV/SURFACE TROUGH. SINCE THE SHRTWV/SURFACE TROUGH IS EXPECTED TO BE A QUICK MOVER... MUCH OF THE CLOUD COVER AND PRECIPITATION WILL END IN THE MORNING. WITH BUILDING HEIGHTS ALOFT AS THE RIDGE MOVES OVER THE SW PORTION OF THE CWA BY 00Z...TEMPERATURES ALOFT SHOULD WARM. THE NAM INDICATES 850MB TEMPS OF 3-5C...AND WITH MORE SUNSHINE EXPECTED TOMORROW...HIGHS SHOULD END UP AT LEAST IN THE LOW 60S EVERYWHERE. THERE WILL LIKELY BE SOME LAKE BREEZES DURING THE AFTERNOON TOO DUE TO THE HIGH PRESSURE RIDGE MOVING OVER THE CWA. .LONG TERM (THU NIGHT INTO NEXT WED)... THE MAIN CONCERN FOR THE EXTENDED PORTION OF THE FCST CONTINUES TO BE THE WX ASSOCIATED WITH A SFC LOW MOVING FORM OKLAHOMA ON THURSDAY EVENING...INTO IOWA BY EARLY FRIDAY AFTN...AND THEN ACROSS THE U.P. SOMETIME FRIDAY NIGHT. GIVEN THE MODEL CONSISTENCY BTWN THE ECMWF/UKMET/GFS DECIDED TO INCREASE POPS TO 80 FOR FRIDAY AFTERNOON INTO SATURDAY EVENING. THIS TIME FRAME SEEMS TO HAVE THE BEST FORCING PER...850-500 DIVQ AND OMEGA FIELDS. OPTED TO LEAVE FOG OUT OF THE FCST FOR NOW...PER LACK OF LOW LEVEL INVERSION IN BUFKIT SOUNDINGS...BUT THIS IS SOMETHING TO CONSIDER FOR FUTURE FCST PACKAGES. ON THE LAKE...AS THE LOW PASSES THROUGH THE UPPER GREAT LAKES...LAKE SUPERIOR SHOULD SEE SOME WINDS TO 30KT...MAINLY FRIDAY EVENING THROUGH SATURDAY AFTN. DIDN'T GET TOO CRAZY WITH WINDS GUSTS...BUT SEEING GUSTS TO GALE FORCE ISN'T OUT OF THE QUESTION. A SECONDARY SFC LOW PASSING THROUGH LOWER MI WILL KEEP WINDS UP OVER THE LAKE THROUGH SUNDAY MORNING...15 TO 25 KT RANGE. A HIGH PRES RIDGE NOSES INTO THE WESTERN CWA SUNDAY EVENING INTO EARLY MONDAY MORNING. THINGS REMAIN PRETTY QUIET WEATHER WISE UNDER THE INFLUENCE OF THIS HIGH. LATEST GUIDANCE ALSO INDICATES A S/W PASSING THROUGH THE FA LATE TUESDAY/EARLY WEDNESDAY. SO PUT IN CHANCE OF SHOWERS FOR DAY 7 STARTING AROUND 6Z...WANTED TO BRING IN POPS A BIT EARLIER THAN THIS SINCE GFS HAS BEEN MORE PROGRESSIVE WITH THIS FEATURE AND GIVEN NW FLOW WOULD HINT AT A MORE PROGRESSIVE S/W THAN NOT. COORDINATED WITH APX/GRB/DLH && .MQT WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING FROM 2 AM EDT TO 8 AM EDT MIZ002-004-005-009>013-084 && $$ AJ(SHORT TERM) PEARSON (LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 915 PM CDT WED SEP 20 2006 .UPDATE... DEW POINTS A LITTLE HIGHER THAN LAST NIGHT BUT VARIOUS TEMPS RUNNING ABOUT SAME AS LAST NIGHT. THERE WILL BE SOME HIGH CLOUDS FILTERING IN SO ADVISORY WILL BE CLOSE. WILL KEEP GOING BASED ON TEMP TRENDS AND IN RIDGE AXIS LONG ENOUGH. OTHERWISE CLOUD AND TEMPS LOOK GOOD ELSEWHERE. TAKING A LOOK AT THE RUC VALID FOR 12Z...ISEN LIFT ON 300 SURFACE JUST REACHING SOUTH CENTRAL MN. WILL BACK OFF ON POPS PORTIONS OF CENTRAL MN UNTIL 15Z. && .PREV DISCUSSION... /ISSUED 335 PM CDT WED SEP 20 2006/ DISCUSSION... A RIDGE OF HIGH PRESSURE STRETCHING NORTHWEST TO SOUTHEAST ACROSS THE CWA AT MID AFTERNOON WILL LEAD TO ANOTHER NIGHT OF FROST MAINLY ALONG AND EAST OF A LINE FROM LXL TO EAU. HAVE ISSUED A FROST ADVISORY FOR THE AFOREMENTIONED AREA. BELIEVE INCREASING LOW LEVEL SE FLOW AND HIGH LEVEL MOISTURE WILL KEEP AREAS TO THE WEST OF THIS LINE FROM EXPERIENCING WIDESPREAD FROST. THE THURSDAY THROUGH SATURDAY PERIOD WILL BE WET. COLLABORATION WITH SURROUNDING OFFICES HAS YIELDED MORE CLOUDS AND HIGHER CHANCES FOR RAIN THURSDAY NIGHT THROUGH THE END OF THE SHORT TERM. GFS/ECMWF SOLUTIONS PREFERRED FOR THE SHORT TERM AS WELL AS THE 20/00Z NCAR ARW WRF. HAVE RAIN SPREADING INTO THE SOUTHWEST CWA THURSDAY MORNING AND THEN PROGRESSING NORTHEAST THROUGH THE DAY. BASICALLY LIKELY TO CATEGORICAL POPS THEREAFTER. HPC QPF FIELDS GENERALLY ACCEPTED. ALSO THE ADJMAV TEMPERATURES PRETTY MUCH USED WITH A COOL...CLOUDY AND DAMP PERIOD AHEAD. LONGER TERM...SATURDAY NIGHT THROUGH WEDNESDAY THE EXTENDED FCST PERIOD WILL BE CHARACTERIZED BY INCREASING TEMPERATURES AND A GENERAL DRYING OUT. THE SOUTHERN HALF OF THE FORECAST AREA WILL REMAIN UNDER THE INFLUENCE OF THE DEPARTING LOW PRESSURE SYSTEM...WITH A FAIRLY POTENT SHORTWAVE MOVING ACROSS THIS AREA ON SATURDAY NIGHT. HAVE INCREASED THE PRECIPITATION CHANCES TO CHANCE CATEGORY ACROSS MOST AREAS TO THE SOUTH OF THE TWIN CITIES...ENDING IT BY SUNDAY. HIGH TEMPERATURES WILL GENERALLY RISE INTO THE MID AND UPPER 60S THROUGH THE EARLY PORTION OF THE WEEK...WITH LOWS MODERATING IN THE MID AND UPPER 40S. ANOTHER CHANCE OF PRECIPITATION WILL MOVE INTO THE AREA ON TUESDAY NIGHT AND WEDNESDAY...AS ANOTHER FRONT MOVES THROUGH THE AREA. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...FROST ADVISORY FROM 1 AM TO 8 AM CDT THURSDAY FOR CHISAGO-ISANTI- KANABEC-MILLE LACS-MORRISON COUNTY(IES). WI...FROST ADVISORY FROM 1 AM TO 8 AM CDT THURSDAY FOR BARRON- CHIPPEWA-DUNN-EAU CLAIRE-POLK-RUSK COUNTY(IES). && $$ RAH/KAT/JPR mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 934 AM EDT WED SEP 20 2006 .SHORT TERM /REST OF TODAY THROUGH THURSDAY/... HAVE MADE SOME MINOR TWEAKS TO THE GRIDDED FORECAST. THESE HAVE RESULTED IN NOT CHANGE TO THE ZONE TEXT PRODUCT. HAVE WARMED AFTERNOON HIGHS TODAY A DEGREE OR TWO IN ALL BUT THE NORTHWEST BASED ON THE RUC MODEL AND FULL SUNSHINE. MORNING DEW POINTS ADJUSTED TO REALITY. A DIURNAL DROP NEAR 25 DEGREES IN THE WEST AND APPROACHING 30 IN THE EAST LOOKS GOOD GIVEN A CONSTANT BREEZE TONIGHT AND GREATER COLD ADVECTION LEFT TO OCCUR IN THE EAST OVERNIGHT TONIGHT. MID 40S TO NEAR 50. THURSDAY HIGHS ACCEPTED. && .PREV DISCUSSION... (ISSUED 305 AM EDT WED SEP 20 2006) SHORT TERM /TODAY THROUGH FRIDAY/... SURFACE FRONT HAS EXITED CENTRAL NORTH CAROLINA. NORTHWEST FLOW BEHIND BOUNDARY HAS USHERED IN DRIER AIR WITH DEWPOINTS IN THE 50S OVER THE PIEDMONT. THIS DRIER AIR SHOULD FILTER INTO THE COASTAL PLAIN AND SANDHILLS PRIOR TO DAYBREAK. HIGH PRESSURE OVER THE UPPER AND MID MISSISSIPPI VALLEY WILL BUILD SOUTHEAST INTO OUR REGION DURING THE NEXT 24 TO 36 HOURS. LOW LEVEL COLD AIR ADVECTION WILL RESULT IN BELOW NORMAL TEMPERATURES TODAY THROUGH THURSDAY. COOLEST TEMPERATURES EXPECTED TONIGHT INTO THURSDAY WITH 850 MILLIBAR TEMPERATURE TROUGH AXIS IN VICINITY. ADJUSTED MAXIMUM TEMPERATURES DOWN A COUPLE OF DEGREES TODAY AND THURSDAY FROM PREVIOUS FORECAST BASED ON PROJECTED LOW LEVEL THICKNESSES. ON FRIDAY...RIDGE AXIS SHIFTS EASTWARD QUICKLY. DECENT ISENTROPIC LIFT NOTED BY FRIDAY MORNING...ESPECIALLY OVER THE WESTERN AND SOUTHERN PIEDMONT. THIS MAY RESULT IN A BIT MORE CLOUDINESS THAN CURRENTLY FORECAST...AND MAY EVEN PRODUCE PATCHES OF DRIZZLE. MODERATING TEMPERATURES BEGIN FRIDAY WITH DEVELOPING SOUTHWEST LOW LEVEL FLOW. LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... MEDIUM RANGE MODELS AT THIS TIME ARE IN FAIRLY GOOD AGREEMENT IN PROJECTED TIMING OF NEXT FRONTAL SYSTEM. FOR SATURDAY INTO SUNDAY...WEAK PERTURBATIONS IN SOUTHWEST FLOW ALOFT AND INCREASINGLY MOIST AND UNSTABLE AIRMASS WILL WARRANT SMALL CHANCE POPS ACROSS CENTRAL NORTH CAROLINA. TEMPERATURES THIS WEEKEND WILL BE 3 TO 6 DEGREES ABOVE NORMAL. BY SUNDAY NIGHT...APPROACHING SURFACE FRONT SHOULD HELP TO AID FOCUS FOR SHOWER AND THUNDERSTORM DEVELOPMENT. FRONT FORECAST TO MOVE EAST OF AREA ON MONDAY. MODEL PROJECTIONS MAY BE TOO FAST AS BEST DYNAMICS LIFT NORTH NORTHEAST WELL AWAY FROM CENTRAL NORTH CAROLINA. THUS...FRONT MAY ACTUALLY DRAG SLOWLY EAST TO SOUTHEAST ACROSS REGION SUNDAY NIGHT INTO MONDAY. WILL CONTINUE TREND OF COOLER AND DRIER CONDITIONS TUESDAY. AVIATION... VFR CONDITIONS THROUGH THE TAF FORECAST PERIOD. NOTICEABLY DRIER AIR WILL CONTINUE TO FEED INTO CENTRAL NORTH CAROLINA FROM THE NORTHWEST BEHIND EXITING COLD FRONT AND ASSOCIATED MOISTURE. DECENT LOW LEVEL COLD AIR ADVECTION UNDERNEATH CYCLONIC FLOW WILL RESULT IN STRATOCUMULUS LATER THIS MORNING AND INTO THE AFTERNOON...WITH PERHAPS A BRIEF PERIOD OF BROKEN STRATOCUMULUS CEILINGS MAINLY ACROSS WESTERN AND NORTHERN SECTIONS. GRADIENT NORTHWEST WINDS OF 10 TO 15 KNOTS TODAY. FORECAST SOUNDINGS INDICATE ONLY 15 KNOTS ATOP THE MIXING LAYER FOR THE AFTERNOON...SO WILL OMIT GUSTINESS FROM TAFS. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 834 PM CDT WED SEP 20 2006 .UPDATE...FOCUS ON FROST ADVISORY. WILL KEEP FROST ADVISORY GOING IN FORECAST TONIGHT...DESPITE A FEW CONCERNS. UNDER CLEAR SKIES AND CALM WINDS...TEMPERATURES ARE FALLING INTO 40S...BUT DEW POINTS ARE HOLDING IN THE UPPER 30S AND LOWER 40S. WOULD LIKE TO SEE SOME MIDDLE 30 DEW POINTS BEING ADVECTED INTO CWA BUT WITH MINIMAL LOW LEVEL WIND FLOW...DEW POINTS WILL NOW HAVE TO FALL ON THEIR OWN...ALONG WITH AIR TEMPERATURE. CURRENT RUC SURFACE AND LOW LEVEL TEMPERATURE AND DEW POINT FIELDS PROGGED TO KEEP SLOWLY SLIDING DOWNWARD...BUT WARM AIR ADVECTION WITH DEVELOPING PLAINS SYSTEM VERY CLOSE TO OFFSETTING THE DOWNWARD TREND. BOTTOM LINE IS THAT IF FROST DOES FORM OVERNIGHT...IT WILL BE OF A VERY BRIEF DURATION...PERHAPS LESS THAN A FEW HOURS. TZ && .PREV DISCUSSION... (ISSUED 334 PM CDT WED SEP 20 2006) DISCUSSION...FORECAST FOCUS ON FROST POTENTIAL TONIGHT...THEN ON LOW PRESSURE AND PRECIPITATION CHANCES FOR THE END OF THE WEEK. DISSIPATING CU ON VISIBLE SATELLITE OVER WI IN LINE WITH LOWERING 1000-850MB RH ON MODELS AS ATMOSPHERE MIXES OUT AND TAPS DRY AIR ABOVE 850 MB DEPICTED ON AREA 12Z RAOBS. MID CLOUDS DEVELOPING OVR WRN S DAKOTA MARKING LEADING EDGE OF WAA AHEAD OF DEEP CLOSED SYSTEM EMERGING FROM THE FOUR CORNERS RGN. MODELS INDICATING STRONGER LLJ WILL LIFT NWD FROM CNTRL PLAINS AND FOCUS WELL TO OUR WEST OVER ERN NEBRASKA/WRN IA INTO SRN MN BY 12Z THURSDAY. WITH CLEAR SKIES AND AXIS OF SFC RIDGE PASSING OVER CWA TONIGHT...EXPECT GOOD RADIATIONAL CONDITIONS FOR AREAS OF FROST TO DEVELOP OVERNIGHT. IN SPITE OF SWLY 850 FLOW DEVELOPING AFTER 06Z OVER SW WI...LOW LVL INVERSION SHOULD PREVENT ANY MIXING DOWN TO SFC. TRAJECTORIES INDICATE SUPPORT FOR LOWS IN THE MID 30S...THO READINGS WILL BE WARMER ALONG LAKE MICHIGAN. WITH THESE TEMPS AND NO WIND WILL ISSUE A FROST ADVISORY FOR ENTIRE CWA TONIGHT...INCLUDING LAKE SHORE COUNTIES WHERE INLAND LOCATIONS WILL BE VULNERABLE. ATTENTION TURNS TO SYSTEM FOR THE END OF THE WEEK. MODELS GENERALLY SIMILAR WITH TIMING OF LEAD WAVE AND ASSOCIATED SFC CYCLOGENESIS THRU 36-48 HR TIME PERIOD. GFS IS QUICKER WITH BRINGING STRONGER 850 MB FLOW AND HIER 850 DEW PTS INTO SW WI BY THURSDAY AFTERNOON. WILL LEAVE LOW CHC POPS IN FAR WRN CWA FOR 21Z THU TO 00Z FRI TIME PD. SHRA LIKELY THURSDAY NIGHT INTO FRI AS LEAD SHRT WAVE TROF LIFTS SOUTH TO NORTH ACROSS RGN. ISO THUNDER ALSO POSSIBLE AS MID LVL LAPSE RATES NEARING 7C/KM SUPPORTIVE OF ELEVATED CONVECTION. MODELS DIVERGE FROM THIS POINT WITH NAM/WRF DEVELOPING AN UNREALISTIC RAPIDLY INTENSIFYING SFC LOW OVER WI AS IT CONSOLIDATES SHRT WAVE ENERGY INTO A TIGHTLY WOUND 500 MB SYSTEM CNTRD OVER MN BY 12Z SAT. CONSENSUS OF OTHER MODELS TRENDS TOWARD MORE OPEN LOOK OF GFS...WITH INITIAL SFC LOW WEAKENING AS IT LIFTS NE OF RGN FRIDAY NGT INTO SATURDAY...THEN A SECOND SFC WAVE LIFTING ALONG BAROCLINIC ZONE SAT AFTERNOON/NGT. WITH CWA TO THE NORTH OF THIS SECOND WAVE...HVY RAIN POTENTIAL INCREASES. GFS KEEPS HEAVIEST RAIN JUST TO THE SOUTH WITH A 1.2 INCH 6-HR ACCUMULATION OVER NRN IL BETWEEN 18Z SAT AND 00Z SUN. SOME QUESTION TO THE AMOUNT OF GULF MOISTURE THAT WILL BE DRAWN INTO SYSTEM SO WILL NOT MENTION HVY RAIN AT THIS TIME...BUT LATER RUNS WILL HAVE TO BE MONITORED. PCPN CHCS DIMINISH SUNDAY AS TRAILING COLD FRONT BEHIND SECOND WAVE DROPS THRU STATE WITH DRIER AIR BEHIND. IN THE EXTENDED...MODELS STILL STRUGGLING WITH HI-AMPLITUDE UPR LEVEL PATTERN...MAINLY WITH POSITION OF ERN PACIFIC RIDGE AND RESULTING DOWNSTREAM TROF STRENGTH/LOCATION. TRENDED WITH CONSENSUS FAVORITE ECMWF AND 00Z GFS ENSEMBLES. THIS SOLUTION WILL TAKE THE COLD FRONT IN THE WAKE OF THE WEEK-END SYSTEM OUT OF SRN WI BY SUNDAY EVENING...A BIT SLOWER THAN THE 06Z GFS. WEAK UPR RDGING BRINGS DRY WEATHER FOR MONDAY THRU TUESDAY...WITH THE NEXT UPR WAVE AND CHC FOR PCPN MOVING INTO THE UPR GREAT LAKES RGN WED. USED A BLEND OF MEXMOS AND ENSEMBLE MOS GUIDANCE FOR TEMPS. MKX WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY FROM 1 AM TO 7 AM THURSDAY FOR WIZ046-WIZ047- WIZ051-WIZ052-WIZ056-WIZ057-WIZ058-WIZ059-WIZ060-WIZ062-WIZ063- WIZ064-WIZ065-WIZ066-WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072. $$ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 225 AM MDT THU SEP 21 2006 .DISCUSSION...FORECAST CONCERNS ARE ON AREAL COVERAGE/PRECIPITATION AMOUNTS THE NEXT SEVERAL DAYS AS WELL AS AFTERNOON TEMPERATURES. WINDS WILL ALSO BE A CONCERN BUT LOOK TO REMAIN BELOW HIGHLITE THRESHOLDS. THANKS TO SURROUNDING OFFICES FOR COLLABORATIVE EFFORTS. AT 08Z A BROAD SURFACE LOW WAS ANALYZED ACROSS SOUTHEAST COLORADO WHILE WATER VAPOR AND RUC ANALYSIS PLACED A STRONG UPPER LOW CENTER IN NORTH CENTRAL NEW MEXICO. PRECIPITATION WAS BEGINNING TO SPREAD INTO THE SOUTHWEST 1/4 OF THE TRI-STATE AREA FROM THE SOUTHWEST. WILL AWAIT THE 06Z NAM AND OTHER VARIOUS RUC MODEL FORECASTS FOR ANY LAST MINUTE CHANGES PRIOR TO ZONE ISSUANCE. TODAY/TONIGHT...VERTICALLY STACKED STORM SYSTEM CURRENTLY OVER NORTH CENTRAL NEW MEXICO WILL MOVE INTO SOUTHWEST KANSAS THIS AFTERNOON THEN LIFT NORTHEAST INTO NORTHWEST IOWA TONIGHT. COMBINATION OF FAVORABLE UPPER LEVEL JET DIVERGENCE AND MID LEVEL LIFT SUGGEST CATEGORICAL POPS FOR THE ENTIRE FORECAST AREA WITH HIGHEST PRECIPITATION AMOUNTS (PER HPC QPF GRAPHICS WHICH WERE USED) WILL EXTEND GENERALLY NORTHEAST TO SOUTHWEST FROM MCCOOK NEBRASKA SOUTHWEST THROUGH GOODLAND SOUTHWEST INTO PARTS OF FAR EASTERN COLORADO DURING THE LATE MORNING THROUGH EARLY AFTERNOON HOURS BEFORE LIFTING NORTHEAST INTO SOUTH CENTRAL NEBRASKA NEAR DAYS END WITH SUBSIDENCE AND DRIER MID LEVEL AIR MOVING IN FROM THE WEST. ANY PRECIP TONIGHT WILL BE WITHIN A FEW HOURS AFTER DARK AND VERY LIGHT AT BEST WITH COVERAGE CONFINED TO THE FAR NORTHEAST 1/4 OF THE AREA. TEMPERATURES TODAY WILL BE BELOW NORMAL WITH LITTLE DIURNAL TREND GIVEN THE WIDESPREAD RAIN EXPECTED. FAR EASTERN COLORADO COUNTIES MAY SEE AN INCREASE IN TEMPS LATE IN THE DAY AS BREAKS IN THE CLOUDCOVER DEVELOP. GENERALLY WENT WITH WINDY CONDITIONS DEVELOPING FROM WEST TO EAST. GUSTS COULD APPROACH LOW END ADVISORY CRITERIA BUT FOR NOW WILL NOT RAISE ANY HIGHLITES. FRIDAY/FRIDAY NIGHT...ANOTHER WAVE MOVES ACROSS THE AREA DURING THE DAY WITH THE NORTHWEST 1/2 OF THE AREA IN THE LEFT FRONT QUAD OF 120KT UPPER JET AND 700-600MB FRONTOGENETIC AREA. WILL MAINTAIN CURRENT WX/POP ORIENTATION WHICH FAVORS THE ABOVE MENTIONED SCENARIO AND UP POPS SLIGHTLY AS CONFIDENCE IS SLIGHTLY HIGHER. NOT A WHOLE LOT OF DIFFERENCE FRIDAY NIGHT WITH UPPER JET STRUCTURE AND LIFT FAVORING THE NORTHWEST 1/2 OF THE AREA. WILL ADJUST WX/POP/QPF GRIDS TO REFLECT HIGHER POPS ACROSS THIS AREA. SATURDAY/SATURDAY NIGHT...UPPER TROUGH AXIS MOVES SOUTH OF THE AREA WITH LITTLE IN THE WAY OF LIFT. CURRENT FORECAST HAS SOME LOW CHANCE POPS EARLY IN THE DAY DECREASING THEM TO SLIGHT CHANCE BY AFTERNOON. THIS SEEMS REASONABLE AND GIVEN SOME UNCERTAINTY AS TO HOW FAST THE TROUGH AXIS SHIFTS SOUTH OF THE AREA WILL MAKE MINIMAL CHANGES AT THIS POINT. QUIET WEATHER SATURDAY NIGHT AS UPPER LEVEL RIDGING TRIES TO BUILD INTO THE AREA FROM THE WEST AS OUR RECENT STORM SYSTEM CONTINUES MOVING EAST. SUNDAY THROUGH WEDNESDAY...NO SIGNIFICANT CHANGES MADE. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 435 AM EDT THU SEP 21 2006 .DISCUSSION... MAIN FCST CONCERNS ARE PCPN TRENDS FROM LATE THU NIGHT INTO SUN. WV IMAGERY AND RUC ANALYSIS INDICATED MID/UPPER LEVEL LOWS OVER NRN QUEBEC AND CO/UT. UPSTREAM...A 150 KT 250 MB JET AND ASSOCIATED SHRTWV WAS DIVING SSE FROM BC. NW FLOW STILL PREVAILED OVER THE UPPER GREAT LAKES AROUND THE QUEBEC LOW. A SHRTWV...RIGHT ENTRANCE OF A 100 KT 300 MB JET...ASSOCIATED BAND OF MID LVL FRONTOGENESIS AND A WEAK SFC TROF HAS SUPPORTED -SHRA OVER ERN LK SUPERIOR. LOW TOPPED ISOLD TSTMS IN THE BAND WERE AIDED BY RELATIVELY WARM LAKE SFC GIVING SBCAPE NEAR 400 J/KG...PER MODIFIED LAPS SNDG. OTHERWISE...AT THE SFC...A RDG EXTENDED FROM WRN ONTARIO AND NRN MN INTO WI WHILE LOW PRES WAS DEVELOPS OVER SE CO. MID/HIGH CLOUDS WITH DEVELOPING WAA PATTERN CLOUDS WERE SPREADING FROM MN AND WRN WI TOWARD UPPER MI. TODAY...EXPECT ANY -SHRA WILL REMAIN MAINLY OVER THE ERN LAKE BUT MAY AFFECT THE NE CWA...E OF KP53...PER SATELLITE/RADAR TRENDS AND 00Z NAM. NAM/RUC RH PROGS SUGGEST THAT MID LVL CLOUDS WILL CONTINUE TO SPREAD TOWARD THE AREA BUT MAY THIN OUT AS THEY MOVE INTO THE MID/UPPER LEVEL CONFLUENCE ZONE OVER THE UPPER LAKES. SO...WITH DECENT AMOUNT OF SUNSHINE AND WEAK WAA WITH SRLY FLOW...TEMPS SHOULD REBOUND TO NEAR GUIDANCE VALUES IN THE LOWER 60S. TONIGHT...305K ISENTROPIC LIFT AHEAD OF THE PLAINS LOW AND WARM FRONT WILL BRING PCPN CHANCES INTO UPPER MI LATE TONIGHT. WITH ONLY MODEST LIFT AND AMOUNT OF DRY AIR IN PLACE...CHANCE POPS IN GOING FCST STILL SEEM ON TRACK. FRI INTO FRI NIGHT...THE GFS/UKMET WERE PREFERRED GIVEN THE GLBL MDLS MORE CONSISTENT PERFORMANCE AND QUESTIONABLE GRASP OF UPSTREAM SHRTWV DETAILS BY THE NAM. STRONG MID/UPPER LEVEL DYNAMICS AHEAD OF THE NEG TILT TROF WITH GOOD UPPER LEVEL DIV...AND QVECTOR CONV SHOULD SUPPORT A BROAD AREA OF RAIN WHICH WILL SPREAD FROM WI ACRS UPPER MI. MDLS CONSENSUS WOULD STILL PLACE BEST CHANCES BTWN 18Z-06Z. 30-35 KT IMPINGING ON THE 850 MB FRONT WITH NEG H8 LI (H8 DEWPOINTS NEAR 11C) SUPPORT TSTM CHANCES OVER THE SOUTH BY LATE AFTERNOON...LINGERING OVER THE SE CWA DURING THE EVENING. SAT INTO SUN...THE GFS REMAINS SLOWER WITH LIFTING THE H5 AND SFC LOW THROUGH THE WRN LAKES COMPARED TO THE UKMET/ECMWF. HOWEVER...GIVEN THE STRENGTH OF THE UPSTREAM BC JET...THE GFS STILL SEEMS PLAUSIBLE. AFTER PCPN TAPERS OFF BEHIND THE INITIAL WAA BAND...THE GFS WITH PROMINENT 700-500 MB DEFORMATION/FGEN BRINGS RAIN BACK ACRS MOST OF UPR MI SAT NIGHT WHILE THE UKMET/ECMWF PUSH THE PCPN THROUGH EARLIER. EXPECT A COMPROMISE WOULD WORK BEST. GIVEN UNCERTAINTY WITH SPEED OF THE SYSTEM...FCST MAINTAINS ONLY CHANCE POPS. .MQT WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING TIL 8 AM EDT MIZ002-004-005-009>013-084 && $$ JLB mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN ANGELO TX 531 AM CDT THU SEP 21 2006 .UPDATE... WILL UPDATE TO EXPAND SLIGHT CHANCE POPS TO THE SOUTHEASTERN COUNTIES FOR THIS MORNING AS ACTIVITY HAS PICKED UP SOUTH OF THE CONCHO VALLEY EARLY THIS MORNING. 20 && .PREV DISCUSSION... (ISSUED 354 AM CDT THU SEP 21 2006) SHORT TERM(TODAY-FRIDAY)... INTENSE UPPER LEVEL SHORTWAVE THIS MORNING OVER MOVING ACROSS NM. THIS SHORTWAVE IS GOING TO BRING STRONG WINDS AND WARMER TEMPERATURES TODAY. THERE IS A SLIGHT CHANCE THIS MORNING FOR TSRA ACROSS THE NORTHERN AREAS...BUT MAIN HAZARD TODAY WILL BE THE WINDS WITH THE SYSTEM. 700MB WINDS ACCORDING TO RUC ANALYSIS THIS MORNING ARE 40- 50KT...SO HAVE KEPT THE WIND ADVISORY UP THIS MORNING FOR THE CONCHO VALLEY NORTHWARD...AND LAKE WIND ADVISORY FOR CONCHO AND MCCULLOCH COUNTIES. ALTHOUGH FUELS ARE GREEN RIGHT NOW...HAVE GONE AHEAD WITH THE RED FLAG WARNING FOR TODAY AS AREA GRASSES WILL QUICKLY DRY OUT WITH THE HEAT AND STRONG WINDS...AS WELL AS A FIRE WEATHER WATCH FOR TOMORROW AS WE WILL ONLY GET HOTTER...AND DRIER. WINDS WILL BE THE MAIN QUESTION FOR TOMORROW AS FAR AS ANY RED FLAG WARNINGS. HAVE KEPT A SLIGHT CHANCE FOR THE NORTHERN HALF OF THE CWA THIS MORNING...AND DROPPED POPS CONSIDERABLY DURING THE AFTERNOON AS DRY WESTERLY WINDS WILL BE MOVING IN AS WELL AS DRY AIR IN THE MID AND UPPER LEVELS. FOR FRIDAY...WILL KEEP THE FORECAST DRY AND WINDY WITH AN INCREASE IN AFTERNOON HIGH TEMPERATURES TO THE MID 90S. ANOTHER SHORTWAVE WILL DIVE SOUTH INTO THE SOUTHERN ROCKIES ON FRIDAY RESULTING IN SIMILAR CONDITIONS FRIDAY...WITH WEAKER WINDS. LONG TERM... BY SATURDAY...A COLD FRONT WILL BE MAKING ITS WAY SOUTH INTO THE BIG COUNTRY AREA AS ANOTHER SHORTWAVE ROUNDS THE UPPER LEVEL TROUGH OVER THE SOUTHERN ROCKIES AND EJECTS TO THE NORTHEAST. WILL KEEP SLIGHT CHANCE SHOWERS AND THUNDERSTORMS FOR SOUTHEASTERN COUNTIES FOR FRIDAY NIGHT THROUGH SATURDAY...AND THEN ALONG THE FRONT FOR SATURDAY NIGHT INTO SUNDAY SOUTH OF THE CONCHO VALLEY. WE ARE CLIPPED BY SPC/S SLIGHT RISK ON SATURDAY/SATURDAY NIGHT...BUT MAIN ACTIVITY FOR THIS RISK AREA WILL BE WELL EAST OF THE CWA. HOWEVER...THE FRONT WILL BE INTERACTING WITH MOIST UNSTABLE AIR OVER SOUTH TEXAS WHICH COULD RESULT IN SOME STRONG THUNDERSTORMS FOR THE NORTHWEST HILL COUNTRY. AFTER SUNDAY...MAINLY DRY AND COOLER WEATHER IS EXPECTED BEHIND THE FRONT AS SURFACE HIGH PRESSURE DOMINATES OUR WEATHER WITH NORTHWEST FLOW TRANSITIONING TO UPPER LEVEL RIDGING OVER THE CWA BY WEDNESDAY. && .SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. && $$ 99/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 354 AM CDT THU SEP 21 2006 .SHORT TERM(TODAY-FRIDAY)... INTENSE UPPER LEVEL SHORTWAVE THIS MORNING OVER MOVING ACROSS NM. THIS SHORTWAVE IS GOING TO BRING STRONG WINDS AND WARMER TEMPERATURES TODAY. THERE IS A SLIGHT CHANCE THIS MORNING FOR TSRA ACROSS THE NORTHERN AREAS...BUT MAIN HAZARD TODAY WILL BE THE WINDS WITH THE SYSTEM. 700MB WINDS ACCORDING TO RUC ANALYSIS THIS MORNING ARE 40- 50KT...SO HAVE KEPT THE WIND ADVISORY UP THIS MORNING FOR THE CONCHO VALLEY NORTHWARD...AND LAKE WIND ADVISORY FOR CONCHO AND MCCULLOCH COUNTIES. ALTHOUGH FUELS ARE GREEN RIGHT NOW...HAVE GONE AHEAD WITH THE RED FLAG WARNING FOR TODAY AS AREA GRASSES WILL QUICKLY DRY OUT WITH THE HEAT AND STRONG WINDS...AS WELL AS A FIRE WEATHER WATCH FOR TOMORROW AS WE WILL ONLY GET HOTTER...AND DRIER. WINDS WILL BE THE MAIN QUESTION FOR TOMORROW AS FAR AS ANY RED FLAG WARNINGS. HAVE KEPT A SLIGHT CHANCE FOR THE NORTHERN HALF OF THE CWA THIS MORNING...AND DROPPED POPS CONSIDERABLY DURING THE AFTERNOON AS DRY WESTERLY WINDS WILL BE MOVING IN AS WELL AS DRY AIR IN THE MID AND UPPER LEVELS. FOR FRIDAY...WILL KEEP THE FORECAST DRY AND WINDY WITH AN INCREASE IN AFTERNOON HIGH TEMPERATURES TO THE MID 90S. ANOTHER SHORTWAVE WILL DIVE SOUTH INTO THE SOUTHERN ROCKIES ON FRIDAY RESULTING IN SIMILAR CONDITIONS FRIDAY...WITH WEAKER WINDS. .LONG TERM... BY SATURDAY...A COLD FRONT WILL BE MAKING ITS WAY SOUTH INTO THE BIG COUNTRY AREA AS ANOTHER SHORTWAVE ROUNDS THE UPPER LEVEL TROUGH OVER THE SOUTHERN ROCKIES AND EJECTS TO THE NORTHEAST. WILL KEEP SLIGHT CHANCE SHOWERS AND THUNDERSTORMS FOR SOUTHEASTERN COUNTIES FOR FRIDAY NIGHT THROUGH SATURDAY...AND THEN ALONG THE FRONT FOR SATURDAY NIGHT INTO SUNDAY SOUTH OF THE CONCHO VALLEY. WE ARE CLIPPED BY SPC/S SLIGHT RISK ON SATURDAY/SATURDAY NIGHT...BUT MAIN ACTIVITY FOR THIS RISK AREA WILL BE WELL EAST OF THE CWA. HOWEVER...THE FRONT WILL BE INTERACTING WITH MOIST UNSTABLE AIR OVER SOUTH TEXAS WHICH COULD RESULT IN SOME STRONG THUNDERSTORMS FOR THE NORTHWEST HILL COUNTRY. AFTER SUNDAY...MAINLY DRY AND COOLER WEATHER IS EXPECTED BEHIND THE FRONT AS SURFACE HIGH PRESSURE DOMINATES OUR WEATHER WITH NORTHWEST FLOW TRANSITIONING TO UPPER LEVEL RIDGING OVER THE CWA BY WEDNESDAY. && .PRELIMINARY POINT TEMPS/POPS... ABILENE 92 67 94 69 / 20 10 0 10 SAN ANGELO 91 67 95 71 / 10 0 0 10 JUNCTION 90 70 94 75 / 10 10 0 20 && .SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 8 AM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER... HASKELL...IRION...JONES...NOLAN...RUNNELS...SHACKELFORD... STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY FROM 8 AM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. && $$ 04/20 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 1021 AM EDT THU SEP 21 2006 .UPDATE...DEWPOINTS THIS MORNING RANGE FROM 63 AT NAPLES TO 73-76 ACROSS THE EAST COAST METROPOLITAN AREAS. THE FRONT HAS "WASHED OUT" AND WHAT IS LEFT OF IT IS LYING ACROSS THE LOCAL GULF WATERS EXTENDING EAST ACROSS MAINLAND MONROE AND MIAMI-DADE COUNTY...THEN NORTHEAST TO NEAR GRAND BAHAMA. SHOWERS HAVE BEEN AFFECTING THE GULF WATERS ALONG THE DISSIPATED FRONT...WITH EVEN ONE BRIEF SMALL SHOWER WHICH DEVELOPED OVER THE EVERGLADES THIS PAST HOUR...BUT HAS SINCE DISSIPATED. GFS HAS A PRETTY GOOD HANDLE ON THE PWAT LAYOUT ACROSS THE AREA...WITH JUST A SLIGHT HIGH BIAS LOCALLY. ITS TREND...ALONG WITH THE NAM...SHOWS THE MOISTURE BOUNDARY ACTUALLY BEGINNING TO DRIFT BACK NORTH THROUGH THIS EVENING. STILL...WITH BROAD SCALE SUBSIDENCE IN PLACE ACROSS THE AREA WITH THE DEPARTING MID/UPPER TROUGH...A MOSTLY DRY DAY IS STILL EXPECTED. BUT HAVE TO ACCOUNT FOR THE POSSIBILITY OF SHRA AND EVEN A FEW TSRA DEVELOPING...WHICH BOTH THE WRF AND RUC SUGGEST AS THE EAST COAST SEA BREEZE DEVELOPS PROVIDING FOR GOOD LOW LEVEL CONVERGENCE. THUS...ADDED TSRA POSSIBILITY INTO THE FCST FOR THIS AFTERNOON ACROSS SOUTHERN AREAS...BUT JUST A SLIGHT CHANCE SINCE IT PROBABLY WILL NOT OCCUR. THIS IS IN LINE WITH SPC WHICH STILL KEEPS THE LOCAL AREA IN GENERAL TSRA POSSIBILITY FOR THIS AFTERNOON. WE WILL KEEP AN EYE ON RH TRENDS FOR GLADES...HENDRY...AND NORTHERN COLLIER COUNTIES SINCE DEWPOINTS ARE ALREADY IN THE 60S THERE AND COULD FALL A LITTLE FURTHER WITH AFTERNOON MIXING...THOUGH AM NOT ANTICIPATING ANY PROBLEMS. /GREGORIA && .PREV DISCUSSION... DISCUSSION...SURFACE HIGH CENTER OVER THE MID ATLC STATES MOVES E INTO THE ATLC TODAY AS AN UPPER RIDGE BUILDS OVER THE FLA PENINSULA. BOTH SYSTEMS MOVE E INTO THE ATLC TONIGHT BUT PERSIST THROUGH THE WEEKEND. BY MON...ANOTHER TROUGH MOVES INTO THE E U.S. SHOVING THE SURFACE/UPPER RIDGES FURTHER E WITH ANOTHER FRONTAL BOUNDARY MOVING INTO N FLA WHICH APPEARS TO MAKE IT TO CENTRAL FLA TUE...STALL AND THEN DISSIPATE. FOR TODAY THROUGH SAT...FRONTAL BOUNDARY (CANNOT CALL IT A "COLD" FRONT SINCE HIGHS TODAY WILL BE NOT TOO DIFFERENT TO WED THOUGH RH A BIT LOWER FOR MOST OF CWA) SLOWLY MOVING S THROUGH INTO EXTREME NW BROWARD AND COLLIER COUNTIES AT THE MOMENT. PUSH BEHIND BOUNDARY DIMINISHING RAPIDLY...AND AT BEST...SYSTEM MAY CLEAR THE EXTREME S TIP OF FLA...STALLING OVER THE KEYS AND CURVING NW INTO THE E GULF OF MEX. THIS LEAVES A SHARP MOISTURE GRADIENT ACROSS MIAMI-DADE AND MAINLAND MONROE COUNTY AS COMPARED TO N PORTIONS OF CWA. MODEL RAOBS INDICATE A POSSIBLE .80 PRECIPITABLE WATER DIFFERENCE FROM GLADES COUNTY TO S MIAMI-DADE COUNTY. WILL PUT SLIGHT CHANCE OF SHOWERS ACROSS S CWA/COASTAL WATERS TODAY. AN ISOLATED TSTM NOT POSSIBLE BUT WILL LEAVE OUT OF ZONES AT THIS TIME. POSSIBLE MINIMAL SHOWERS DADE MAINLAND MONROE WATERS/COAST TONIGHT AS EASTERLY WINDS RAPIDLY DEVELOP JUST N OF STALLED BOUNDARY. MINIMAL SHOWERS AGAIN SAME AREA FRI AS DRIER AIR ALOFT MAY CAP VERTICAL DEVELOPMENT. STEERING WINDS ERRATIC AND MOVEMENT VIRTUALLY NIL. SAT SIMILAR AS DRIER AIR ADVECTS ALOFT FROM E AND SHOWERS AGAIN NEAR STALLED BOUNDARY. TEMPS TODAY 3-5 DEGREES COOLER THAN WED AND LOWER RH EXCEPT FOR THE EXTREME S. TEMPS AND RH SLOW REBOUND AS EASTERLY WINDS DEVELOP. EXTENDED PERIOD...SUN THROUGH WED...DRIER AIR ALOFT PERSISTS OVER CWA SUN/MON BUT MINIMAL POPS POSSIBLE CWA. WINDS BECOME SW ALOFT AHEAD OF FRONT TUE/WED INCREASING MOISTURE AND INCREASING CHANCES OF RAIN. AVIATION...A WEAK FRONTAL BOUNDARY IS SLOWLY SLIDING SOUTH ACROSS THE AREA. WINDS WILL BE LIGHT TO CALM TONIGHT, HOWEVER, WITH THE LIGHT WINDS AND AMPLE MOISTURE PATCHY FOG MAY DEVELOP ACROSS SOUTH FLORIDA. AS OF 5Z HST WAS ALREADY REPORTING BR TO 7SM AND SOME STATIONS IN CENTRAL FLORIDA WERE DOWN TO 5SM. THE PATCHY FOG WILL QUICKLY BURN OFF AFTER SUNRISE. ON THURSDAY NOT MUCH WEATHER TO SPEAK OF EXCEPT ACROSS THE KEYS AND SOUTH MIAMI DADE. THE FRONT WILL STILL BE IN THE VICINITY SO THERE IS A SLIGHT CHANCE THAT A FEW SHOWERS MAY DEVELOP. THE WINDS WILL ALSO BECOME MORE NORTHEASTERLY TO EAST NORTHEASTERLY THROUGH THE DAY. MARINE...WEAK NORTHERLY FLOW...10 KNOTS OR LESS TODAY...BECOMING E BY TONIGHT AND POSSIBLY BECOMING 10 TO 15 KNOTS OUTER GULF WATERS FRI NIGHT. LIGHT EASTERLY FLOW PERSISTS THROUGH THE WEEKEND BECOMING SW MON AHEAD OF THE NEXT "COLD" FRONT. FIRE WEATHER...STALLING OF FRONT ELIMINATES EXTREME DRY AIR ADVEC -TION. DEW POINTS AT LOWEST AROUND 60 NW INTERIOR ZONES. 2 TO 3 HOURS OF RH BETWEEN 35 TO 40% POSSIBLE. LOW LEVEL MOISTURE INCREASES FRI WITH NO PROBLEMS ANTICIPATED. && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ 57 fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1045 AM CDT THU SEP 21 2006 .DISCUSSION... FORECAST LOOKS ON TRACK TODAY AS IT STAYS DRY THROUGH SUNSET AS HIGH AND MID CLOUDS INCREASE/THICKEN FROM THE WEST THIS AFTERNOON AND INTO THIS EVENING. MILDER HIGHS AROUND 70F WITH SSE WINDS 10 TO 20 MPH... BUT WILL BELOW NORMAL HIGHS IN THE MID TO UPPER 70S. 15Z/10 AM SURFACE ANALYSIS SHOWS 1023 MB HIHG PRESSURE ALONG THE WV/VA BORDER AND RIDGING ACROSS THE EASTERN US EAST OF THE MS RIVER. VERY DEEP 988 MB LOW PRESSURE WAS ALONG THE CO/KS BORDER. ALOFT A 550 DM 500 MB CUTOFF LOW WAS OVER FAR WESTERN KS SO VERTICALLY STACKED LOW PRESSURE SYSTEM AND UNUALLY DEEP/FAR SOUTH FOR THIS TIME OF YEAR. UPPER LEVEL RIDGE WAS OVER THE GULF OF MEXICO/FL AND RIDGING NORTH ACROSS THE EASTERN U.S. RADAR MOSAIC SHOWS CONVECTION OVER THE WESTERN HALF OF IA/MO AND LIFTING NNE. AFTER ANOTHER COOL START TO THE DAY WITH LOWS IN THE UPPER 30S TO MID 40S...10 AM TEMPS REBOUNDED INTO THE UPPER 50S AND LOWER 60S THANKS TO SSE BREEZES 10 TO 20 MPH AND PARTLY TO MOSTLY SUNNY SKIES WITH THIN CIRRUS AND PATCHES OF MID LEVEL CLOUDS. DEWPOINTS STILL PRETTY LOW IN THE 40S. RUC AND NAM/WRF DRIFT SURFACE HIGH PRESSURE TO THE MID ATLANTIC COAST LATER TODAY AS LOW PRESSURE DEEPENS NE TO 986 MB INTO NORTH CENTRAL KS BY 00Z/SUNSET. INCREASING PRESSURE GRADIENT OVER IL SUPPORTING SSE BREEZES 10 TO 20 MPH AND SOME GUSTS IN THE 20S LIKE GALESBURG ALREADY HAS GUST OF 24 MPH. MID/HIGH CLOUDS TO CONTINUE TO INCREASE/THICKEN FROM THE WEST INTO THIS EVENING...BUT SURFACE AND UPPER LEVEL HIGH PRESSURE EAST OF IL SHOULD KEEP THE STATE DRY THROUGH AT LEAST SUNSET. MODELS SHOWS SOME SHORT WAVE ENERGY LIFTING NE INTO IL AROUND SUNSET AND INTO THIS EVENING...BUT INITIALLY DRY SINCE NEEDS TO MOISTEN UP FAIRLY DRY ATMOSPHERE OVER IL. RUC AND NAM/WRF SIMILAR WITH HIGHS AROUND 21Z/4 PM IN THE UPPER 60S/LOWER 70S WITH COOLEST READINGS EAST. && .PREV DISCUSSION...PLENTY OF CHALLENGES WITH THIS FORECAST PACKAGE...AS COMPLEX WEATHER SCENARIO UNFOLDS OVER THE NEXT 72 HOURS. 06Z SURFACE ANALYSIS INDICATES WEAK RETURN FLOW ACROSS CENTRAL ILLINOIS...AS RIDGE AXIS SHIFTS OFF TO THE EAST. MEANWHILE...LOW PRESSURE IS ORGANIZING ACROSS EASTERN COLORADO IN ADVANCE OF A VIGOROUS UPPER LOW CENTERED OVER THE FOUR-CORNERS REGION. AHEAD OF THIS SYSTEM...50-60KT LLJ IS ENHANCING CONVECTION ACROSS THE CENTRAL PLAINS...WHILE 90KT 250MB JET STREAK IS HELPING TRIGGER ISOLATED SHOWERS/STORMS ACROSS NORTHEAST IOWA. SHORT TERM...TODAY THROUGH SATURDAY... MODELS IN REASONABLE AGREEMENT IN THE SHORT-TERM...WITH THE NAM-WRF BEING SLOWER THAN THE GFS WITH THE EASTWARD PROGRESSION OF THE COLORADO LOW. GIVEN THAT THE SYSTEM IS RAPIDLY BECOMING VERTICALLY STACKED...PREFER A SLOWER MOVEMENT...SO WILL SIDE CLOSER TO THE NAM-WRF WITH REGARDS TO PRECIP ONSET. GULF IS CURRENTLY CUT-OFF DUE TO SURFACE RIDGING...BUT WILL OPEN UP LATER TODAY. WITH LIMITED MOISTURE RETURN TO WORK WITH...THINK THE APPROACHING SYSTEM WILL TURN OUT TO BE A HIGH POP/LOW QPF EVENT TONIGHT INTO FRIDAY MORNING. GIVEN INITIAL DRY MID AND LOW-LEVEL PROFILES AND SLOWER MOVEMENT...HAVE DROPPED POPS ENTIRELY FOR TODAY. WILL BRING IN CHANCE POPS DURING THE EVENING...WITH LIKELY AFTER MIDNIGHT ACROSS THE WESTERN HALF OF THE KILX CWA. HIGHEST POPS THEN SHIFT INTO THE EASTERN CWA BY FRIDAY MORNING...BEFORE EXITING THE REGION BY AFTERNOON. MODELS CONTINUE TO INDICATE DECENT MID-LEVEL DRY-SLOTTING FRIDAY AFTERNOON...SO HAVE LOWERED POPS BACK INTO THE CHANCE CATEGORY ACROSS THE BOARD AT THAT TIME. UPPER LOW LIFTS INTO THE UPPER MIDWEST FRIDAY NIGHT...AS NEXT DISTURBANCE TRACKS THROUGH THE CENTRAL ROCKIES. MODELS IN RATHER POOR AGREEMENT WITH SECOND SYSTEM...AS THEY STRUGGLE WITH WHETHER OR NOT TO MERGE SECOND SURFACE WAVE WITH FIRST WAVE. PREFER THE GFS/ECMWF SOLUTION HERE...KEEPING THE SYSTEMS SEPARATE AND FEATURING A SLOWER EVOLUTION. GFS DEVELOPS SURFACE LOW ACROSS THE TEXAS PANHANDLE BY 00Z SAT...THEN TRACKS IT NORTHEASTWARD INTO EASTERN KANSAS BY 12Z SAT. PLENTY OF WAA AHEAD OF SYSTEM WILL ENHANCE CONVECTION ALONG DEVELOPING WARM FRONT FRIDAY NIGHT...MAINLY ACROSS THE CENTRAL AND SOUTHERN CWA. HAVE THEREFORE GONE WITH LIKELY POPS ALONG AND SOUTH OF I-72...WITH LOWER POPS TO THE NORTHWEST. LOW TRACKS TOWARD CHICAGO ON SATURDAY...PLACING MUCH OF THE KILX CWA IN THE WARM SECTOR. SHOWERS/STORMS APPEAR LIKELY ON SATURDAY...WITH POTENTIAL FOR SEVERE DUE TO STRONG UPPER DYNAMICS AND AMPLE LOW-LEVEL MOISTURE. LOW TRACKS FURTHER NORTHEAST SATURDAY NIGHT...DRAGGING COLD FRONT THROUGH THE STATE. WILL GRADUALLY LOWER POPS FROM WEST TO EAST ACCORDINGLY. LONG TERM...SUNDAY THROUGH WEDNESDAY... DESPITE SURFACE LOW BEING FAR TO THE NORTHEAST...SCATTERED SHOWERS WILL BE POSSIBLE ON SUNDAY AS UPPER TROUGH AXIS SWINGS THROUGH THE REGION. AFTER THAT...DRY WEATHER WILL BE ON TAP FOR MONDAY AND TUESDAY...BEFORE NORTHERN STREAM SYSTEM AND ACCOMPANYING SURFACE FRONT APPROACH BY THE MIDDLE OF THE WEEK. ECMWF IS A BIT FASTER WITH THE SYSTEM THAN THE GFS...BUT BOTH INDICATE FRONT COMING INTO AREA SOMETIME WEDNESDAY OR WEDNESDAY NIGHT. WILL THEREFORE CARRY 20 POPS ACROSS THE WEST WEDNESDAY...AND EVERYWHERE WEDNESDAY NIGHT. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HUETTL/BARNES il AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN ANGELO TX 1008 AM CDT THU SEP 21 2006 .UPDATE... MID MORNING GOES WATER VAPOR IMAGERY SHOWED A DEEP CLOSED UPPER LOW NEAR THE WESTERN OK PANHANDLE...WITH A DRY SLOT ROUNDING THE BASE OF THE UPPER LOW INTO WEST TX. THIS DRYSLOT WAS QUITE IMPRESSIVE ON THE 12Z AMA SOUNDING. FURTHER SOUTH...12Z MAF SOUNDING NOT NEARLY AS DRY. AS IS EXPECTED IN SUCH A WELL MIXED LOWER ATMOSPHERE...SURFACE DEWPOINTS REFLECTED THE LOW LEVEL MOISTURE DISPARITY ON THE MORNING SOUNDINGS. DEWPOINTS UPSTREAM OF WEST CENTRAL TX WERE IN THE 50S OVER FAR WEST TX...WHILE 30 DEGREE DEWPOINTS WERE WORKING EAST FROM EAST CENTRAL NM...INTO THE TX PANHANDLE AND SOUTH PLAINS. THE 12Z NAM MODEL APPEARED TO HAVE A GOOD HANDLE ON LOW LEVEL DEWPOINTS. SLIGHTLY BETTER MOISTURE NOTWITHSTANDING...RAIN CHANCES FOR WEST CENTRAL TX HAVE DECREASED SIGNIFICANTLY FROM EARLIER THIS MORNING. MAY SEE SOME SOUTHWARD EXTENSION OF SHOWERS INTO THE NORTHERN BIG COUNTRY WITH THE APPROACH OF THE UPPER LOW...AND HAVE CONTINUED 20 POPS OVER THESE AREAS. FUEL MOISTURE CRITERIA REMAINS MARGINAL...BUT RED FLAG WARNING CONTINUES FOR AREAS ROUGHLY WEST OF AN OZONA TO THROCKMORTON LINE. CERTAIN LIVE FUELS SUCH AS JUNIPER AND CEDAR MAY BE AT HEIGHTENED RISK OF IGNITION IF ENOUGH PREHEATING CAN OCCUR. 14 && .PREV DISCUSSION... (ISSUED 654 AM CDT THU SEP 21 2006) AVIATION... LOW LEVEL JET SHOWING UP AT KSJT AND KDYX RADARS WITH VAD WINDS OF 45 AND 50 KTS RESPECTIVELY. KEPT MENTION OF LOW LEVEL WIND SHEAR UNTIL 15Z...EVEN THOUGH A BAND OF LIGHT SHOWERS JUST THE EAST OF ABILENE AND SAN ANGELO HAS MIXED OUT THE ATMOSPHERE SOMEWHAT WITH GUSTS UP TO 25 MPH. MID LEVEL CLOUDS SHOULD MOVE EAST OF KABI AND KSJT BY 15Z. MAY SEE SOME LOW LEVEL CLOUDS 1200 TO 1500 FEET AGL IN SOUTHERN SECTIONS OF CWA...NEAR SONORA AND JUNCTION UNTIL 15-16Z. STRONG SURFACE WINDS WILL BE THE MAIN PROBLEM FOR AVIATION TODAY WITH A STRONG SURFACE LOW OVER SOUTHEAST COLORADO. SURFACE WINDS SHOULD DECOUPLE AROUND 23Z. MAY TEMPORARILY SEE SOME LLWS PROBLEMS AGAIN DUE TO STRONGER WINDS ALOFT...BUT GFS INDICATING A 30 KT LOW LEVEL JET AT THAT TIME...TO WILL LEAVE OUT OF TAFS FOR NOW. LATER SHIFTS HOWEVER WILL NEED TO REEVALUATE LLWS IF WINDS ALOFT DO NOT DECREASE QUITE AS FAST. PREV DISCUSSION... (ISSUED 531 AM CDT THU SEP 21 2006) UPDATE... WILL UPDATE TO EXPAND SLIGHT CHANCE POPS TO THE SOUTHEASTERN COUNTIES FOR THIS MORNING AS ACTIVITY HAS PICKED UP SOUTH OF THE CONCHO VALLEY EARLY THIS MORNING. 20 PREV DISCUSSION... (ISSUED 354 AM CDT THU SEP 21 2006) SHORT TERM(TODAY-FRIDAY)... INTENSE UPPER LEVEL SHORTWAVE THIS MORNING OVER MOVING ACROSS NM. THIS SHORTWAVE IS GOING TO BRING STRONG WINDS AND WARMER TEMPERATURES TODAY. THERE IS A SLIGHT CHANCE THIS MORNING FOR TSRA ACROSS THE NORTHERN AREAS...BUT MAIN HAZARD TODAY WILL BE THE WINDS WITH THE SYSTEM. 700MB WINDS ACCORDING TO RUC ANALYSIS THIS MORNING ARE 40- 50KT...SO HAVE KEPT THE WIND ADVISORY UP THIS MORNING FOR THE CONCHO VALLEY NORTHWARD...AND LAKE WIND ADVISORY FOR CONCHO AND MCCULLOCH COUNTIES. ALTHOUGH FUELS ARE GREEN RIGHT NOW...HAVE GONE AHEAD WITH THE RED FLAG WARNING FOR TODAY AS AREA GRASSES WILL QUICKLY DRY OUT WITH THE HEAT AND STRONG WINDS...AS WELL AS A FIRE WEATHER WATCH FOR TOMORROW AS WE WILL ONLY GET HOTTER...AND DRIER. WINDS WILL BE THE MAIN QUESTION FOR TOMORROW AS FAR AS ANY RED FLAG WARNINGS. HAVE KEPT A SLIGHT CHANCE FOR THE NORTHERN HALF OF THE CWA THIS MORNING...AND DROPPED POPS CONSIDERABLY DURING THE AFTERNOON AS DRY WESTERLY WINDS WILL BE MOVING IN AS WELL AS DRY AIR IN THE MID AND UPPER LEVELS. FOR FRIDAY...WILL KEEP THE FORECAST DRY AND WINDY WITH AN INCREASE IN AFTERNOON HIGH TEMPERATURES TO THE MID 90S. ANOTHER SHORTWAVE WILL DIVE SOUTH INTO THE SOUTHERN ROCKIES ON FRIDAY RESULTING IN SIMILAR CONDITIONS FRIDAY...WITH WEAKER WINDS. LONG TERM... BY SATURDAY...A COLD FRONT WILL BE MAKING ITS WAY SOUTH INTO THE BIG COUNTRY AREA AS ANOTHER SHORTWAVE ROUNDS THE UPPER LEVEL TROUGH OVER THE SOUTHERN ROCKIES AND EJECTS TO THE NORTHEAST. WILL KEEP SLIGHT CHANCE SHOWERS AND THUNDERSTORMS FOR SOUTHEASTERN COUNTIES FOR FRIDAY NIGHT THROUGH SATURDAY...AND THEN ALONG THE FRONT FOR SATURDAY NIGHT INTO SUNDAY SOUTH OF THE CONCHO VALLEY. WE ARE CLIPPED BY SPC/S SLIGHT RISK ON SATURDAY/SATURDAY NIGHT...BUT MAIN ACTIVITY FOR THIS RISK AREA WILL BE WELL EAST OF THE CWA. HOWEVER...THE FRONT WILL BE INTERACTING WITH MOIST UNSTABLE AIR OVER SOUTH TEXAS WHICH COULD RESULT IN SOME STRONG THUNDERSTORMS FOR THE NORTHWEST HILL COUNTRY. AFTER SUNDAY...MAINLY DRY AND COOLER WEATHER IS EXPECTED BEHIND THE FRONT AS SURFACE HIGH PRESSURE DOMINATES OUR WEATHER WITH NORTHWEST FLOW TRANSITIONING TO UPPER LEVEL RIDGING OVER THE CWA BY WEDNESDAY. SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. $$ SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. $$ && .SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. && $$ 99/99 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN ANGELO TX 654 AM CDT THU SEP 21 2006 .AVIATION... LOW LEVEL JET SHOWING UP AT KSJT AND KDYX RADARS WITH VAD WINDS OF 45 AND 50 KTS RESPECTIVELY. KEPT MENTION OF LOW LEVEL WIND SHEAR UNTIL 15Z...EVEN THOUGH A BAND OF LIGHT SHOWERS JUST THE EAST OF ABILENE AND SAN ANGELO HAS MIXED OUT THE ATMOSPHERE SOMEWHAT WITH GUSTS UP TO 25 MPH. MID LEVEL CLOUDS SHOULD MOVE EAST OF KABI AND KSJT BY 15Z. MAY SEE SOME LOW LEVEL CLOUDS 1200 TO 1500 FEET AGL IN SOUTHERN SECTIONS OF CWA...NEAR SONORA AND JUNCTION UNTIL 15-16Z. STRONG SURFACE WINDS WILL BE THE MAIN PROBLEM FOR AVIATION TODAY WITH A STRONG SURFACE LOW OVER SOUTHEAST COLORADO. SURFACE WINDS SHOULD DECOUPLE AROUND 23Z. MAY TEMPORARILY SEE SOME LLWS PROBLEMS AGAIN DUE TO STRONGER WINDS ALOFT...BUT GFS INDICATING A 30 KT LOW LEVEL JET AT THAT TIME...TO WILL LEAVE OUT OF TAFS FOR NOW. LATER SHIFTS HOWEVER WILL NEED TO REEVALUATE LLWS IF WINDS ALOFT DO NOT DECREASE QUITE AS FAST. && .PREV DISCUSSION... (ISSUED 531 AM CDT THU SEP 21 2006) UPDATE... WILL UPDATE TO EXPAND SLIGHT CHANCE POPS TO THE SOUTHEASTERN COUNTIES FOR THIS MORNING AS ACTIVITY HAS PICKED UP SOUTH OF THE CONCHO VALLEY EARLY THIS MORNING. 20 PREV DISCUSSION... (ISSUED 354 AM CDT THU SEP 21 2006) SHORT TERM(TODAY-FRIDAY)... INTENSE UPPER LEVEL SHORTWAVE THIS MORNING OVER MOVING ACROSS NM. THIS SHORTWAVE IS GOING TO BRING STRONG WINDS AND WARMER TEMPERATURES TODAY. THERE IS A SLIGHT CHANCE THIS MORNING FOR TSRA ACROSS THE NORTHERN AREAS...BUT MAIN HAZARD TODAY WILL BE THE WINDS WITH THE SYSTEM. 700MB WINDS ACCORDING TO RUC ANALYSIS THIS MORNING ARE 40- 50KT...SO HAVE KEPT THE WIND ADVISORY UP THIS MORNING FOR THE CONCHO VALLEY NORTHWARD...AND LAKE WIND ADVISORY FOR CONCHO AND MCCULLOCH COUNTIES. ALTHOUGH FUELS ARE GREEN RIGHT NOW...HAVE GONE AHEAD WITH THE RED FLAG WARNING FOR TODAY AS AREA GRASSES WILL QUICKLY DRY OUT WITH THE HEAT AND STRONG WINDS...AS WELL AS A FIRE WEATHER WATCH FOR TOMORROW AS WE WILL ONLY GET HOTTER...AND DRIER. WINDS WILL BE THE MAIN QUESTION FOR TOMORROW AS FAR AS ANY RED FLAG WARNINGS. HAVE KEPT A SLIGHT CHANCE FOR THE NORTHERN HALF OF THE CWA THIS MORNING...AND DROPPED POPS CONSIDERABLY DURING THE AFTERNOON AS DRY WESTERLY WINDS WILL BE MOVING IN AS WELL AS DRY AIR IN THE MID AND UPPER LEVELS. FOR FRIDAY...WILL KEEP THE FORECAST DRY AND WINDY WITH AN INCREASE IN AFTERNOON HIGH TEMPERATURES TO THE MID 90S. ANOTHER SHORTWAVE WILL DIVE SOUTH INTO THE SOUTHERN ROCKIES ON FRIDAY RESULTING IN SIMILAR CONDITIONS FRIDAY...WITH WEAKER WINDS. LONG TERM... BY SATURDAY...A COLD FRONT WILL BE MAKING ITS WAY SOUTH INTO THE BIG COUNTRY AREA AS ANOTHER SHORTWAVE ROUNDS THE UPPER LEVEL TROUGH OVER THE SOUTHERN ROCKIES AND EJECTS TO THE NORTHEAST. WILL KEEP SLIGHT CHANCE SHOWERS AND THUNDERSTORMS FOR SOUTHEASTERN COUNTIES FOR FRIDAY NIGHT THROUGH SATURDAY...AND THEN ALONG THE FRONT FOR SATURDAY NIGHT INTO SUNDAY SOUTH OF THE CONCHO VALLEY. WE ARE CLIPPED BY SPC/S SLIGHT RISK ON SATURDAY/SATURDAY NIGHT...BUT MAIN ACTIVITY FOR THIS RISK AREA WILL BE WELL EAST OF THE CWA. HOWEVER...THE FRONT WILL BE INTERACTING WITH MOIST UNSTABLE AIR OVER SOUTH TEXAS WHICH COULD RESULT IN SOME STRONG THUNDERSTORMS FOR THE NORTHWEST HILL COUNTRY. AFTER SUNDAY...MAINLY DRY AND COOLER WEATHER IS EXPECTED BEHIND THE FRONT AS SURFACE HIGH PRESSURE DOMINATES OUR WEATHER WITH NORTHWEST FLOW TRANSITIONING TO UPPER LEVEL RIDGING OVER THE CWA BY WEDNESDAY. SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. $$ && .SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. && $$ 99/99/04 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 312 PM CDT THU SEP 21 2006 .DISCUSSION... MAIN CONCERN DEALS WITH THE POTENTIAL FOR SIGNIFICANT SEVERE WEATHER EVENT TOMORROW AND TOMORROW NIGHT PER SPC SWODY2. STILL PREFER THE GFS BECAUSE OF IT'S CONSISTENCY AND SUPPORT FROM THE OTHER SHORT TERM MODELS AND THE SREF. THE NAM TIMING LOOKS MORE LIKE THE GFS TODAY... BUT IT IS QUITE A BIT DEEPER WITH THE LOW THAN THE OTHER MODELS. LARGE AREA OF RAIN/ISOLD TSRA OVER ERN KS/WRN MO HAS MADE LITTLE ADVANCEMENT EWD TODAY. DO THINK IT WILL GRADUALLY SPILL INTO CNTRL MO EARLY THIS EVENING...AND THEN ERN MO AND IL COUNTIES LATE EVENING/OVERNIGHT AS LARGE SCALE MID LEVEL ASCENT AND LOW LEVEL CONVERGENCE/MOISTURE TRANSPORT SHIFTS EWD AS MID/UPR LEVEL SHORTWAVE TROUGH AND LOW LEVEL JET TRANSLATE NEWD. HAVE LIKELY POPS GOING FOR SHRA WITH CHC OF TSRA TONIGHT. EXPECT SOME ONGOING CLUSTERS OF TSRA MAINLY OVER THE SRN AND ERN CWA EARLY IN FRIDAY MORNING...WHICH MAY HAVE SOME IMPACT ON AVAILABLE INSTABILITY THROUGH MIDDAY. DO NOT EXPECT WIDESPREAD SHRA/TSRA TOMORROW AS THERE IS NO SINGLE/STRONG SHORTWAVE TROUGH THAT WILL MOVE ACROSS THE AREA. HOWEVER...GFS DOES SHOW A SUBTLE VORT THAT WILL SUPPLY SOME MODEST LARGE SCALE ASCENT MOVING THROUGH THE FAST SWLY MID-UPR LEVEL FLOW. THERE IS ALSO SOME DECENT SFC CONVERGENCE ALONG FRONT THAT WILL EXTEND FROM NERN INTO CNTRL MO BY AFTN. THERE SHOULD BE SOME DAYTIME HEATING WITH BREAKS IN THE CLOUDS IN THE WAKE OF THE OVERNIGHT SHORTWAVE...ALLOWING TEMPS TO CLIMB INTO THE UPPER 70S AND LOWER 80S BY AFTN. DEWPOINTS ALSO SHOULD CLIMB INTO THE MID-UPR 60S BEHIND THE WARM FRONT MOVING NEWD ACROSS THE AREA. MODIFIED MODEL SOUNDINGS AT COU LATE TOMORROW AFTN HAVE MLCAPES AROUND 2000 J/KG WITH SOME SMALL CIN. GIVEN THE FAST FLOW ALOFT...DEEP LAYER SHEAR IS GOING TO BE AND IMPRESSIVE 60-70 KTS...WITH 0-1KM SRH AROUND 250 M2/S2. HAVE LOW LIKELY POPS GOING TOMORROW WITH SVR WORDING. PER SWODY2...CONCERN IS THAT SCT LONG LIVED SUPERCELLS WILL DEVELOP CAPABLE OF PRODUCING SIGNIFICANT SEVERE WEATHER. CHANCE OF SEVERE WEATHER LOOKS TO LINGER THROUGH TOMORROW NIGHT AND EVEN ON SATURDAY. CONTINUED LOW LEVEL MOISTURE TRANSPORT INTO THE AREA WITH PERSISTENT LOW LEVEL CONVERGENCE AND SUBTLE SHORTWAVES WARRANT KEEPING THUNDERSTORMS GOING ALL NIGHT TOMORROW NIGHT. MLCAPES STAY AOA 1000 J/KG WITH NEW SFC LOW DEVELOPING ALONG FRONT OVER WRN MO BY 12Z SATURDAY...SO HAVE KEPT SVR WORDING GOING ALL NIGHT. LARGE SCALE ASCENT WILL INCREASE ON SATURDAY AS TROUGH AND ACCOMPANYING SFC FRONT MOVES THROUGH THE AREA. GFS HAS MLCAPES ONCE AGAIN AROUND 2000 J/KG ON SATURDAY WITH DEEP LAYER SHEAR OF 50-70KTS. CHC OF TSRA FINALLY ENDS FROM WEST TO EAST SATURDAY NIGHT AS SFC FRONT MOVES THROUGH. KEPT MOSTLY CLOUDY SKIES WITH A SLIGHT CHC OF SHRA ON SUNDAY GIVEN LOW LEVEL MOISTURE AND CYCLONIC CURVATURE. TEMPERATURES ARE A EQUAL BLEND OF THE AGREEABLE GUIDANCE AND PERSISTENCE. FOR THE EXTENDED PERIOD (SUNDAY NIGHT - THURSDAY)...DEEP H500 TROF WILL BEGIN THE PERIOD JUST E OF THE FA...WITH SOME RESIDUAL ENERGY LINGERING OVERHEAD THRU LATE MONDAY...BUT LACK OF MOISTURE TO WORK WITH SHOULD LARGELY PRECLUDE PCPN...AND SOME RIDGING IS EXPECTED TO BE IN PLACE AT THE SURFACE. ANOTHER H500 TROF WILL DEEPEN OVER THE N CNTRL CONUS LATE IN THE PERIOD BEGINNING WEDNESDAY...BUT MOST OF THE UPPER LEVEL ENERGY WITH THIS WILL PASS TO OUR N. AT THE SURFACE... RATHER SHARPLY DEFINED CDFNT WILL MOVE THRU DURING WEDNESDAY. ALTHOUGH MOISTURE RETURN WILL BE MORE LIMITED THAN SYSTEM EXPECTED FOR THIS WEEKEND...SHOULD STILL BE ENOUGH OF A THREAT TO NOW INTRODUCE SLIGHT CHANCES IN FOR THE WEDNESDAY/WEDNESDAY NIGHT TIME PERIOD...WITH THUNDER POSSIBLE WEDNESDAY AFTERNOON. HI PRES WILL THEN BUILD IN FOR THURSDAY. TEMPS WILL GENERALLY BE AROUND NORMAL THRU MID WEEK...WHEN FROPA WILL BRING IN NEXT SURGE OF COOLER AIR AND DROP TEMPS TO ABOUT 5-10F BELOW NORMAL. BRITT/TES && .AVIATION... FOR THE 18Z TAFS...RAIN SHIELD OVER WRN MO AND ERN KS IS MAKING SLOW EWD PROGRESS DUE TO DRIER AIR ACROSS ERN MO AND WRN IL. THIS PCPN IS OCCURRING IN ADVANCE OF A RATHER POTENT SHRTWV TROF CURRENTLY LOCATED FROM THE UPR LOW IN WRN KS SWD THRU WRN OK. THIS SHRTWV SHOULD CONTINUE TO LIFT NEWD THIS AFTERNOON AND TONIGHT ACCOMPANIED BY THE AFOREMENTIONED RAIN SHIELD. HOW QUICKLY IT SPREADS EWD AND HOW MUCH IT HOLDS INTACT IS THE BIGGEST QUESTION. THE NEW FCST IS A BLEND OF EXTRAPOLATION AND THE RUC/NAM...AND THUS SHOULD SEE SOME COVERAGE OF LGT RAIN OR SHRA MOVE FROM WEST TO EAST INTO THE TAF SITES FROM MID-LATE AFTERNOON INTO THE EVENING. RAIN SHOULD BE MAINLY WITH VFR CIGS/VSBYS. AFTER THIS INTIAL BAND OF PCPN THINK THE NEXT WAVE OF PCPN...THIS WAVE CONTAINING TSRA WL PRIMARILY AFFECT THE NW HALF OF MO LATE THIS EVENING OVERNIGHT. SFC WINDS WL HAVE A TENDENCY TO BE GUSTY AND MAY ACTUALLY INCREASE LATER TNGT AS BOTH THE SFC PRESSURE GRADIENT INCREASES AND THE S-SWLY LLJ TRANSLATES EWD. MAY SEE SOME MVFR CIGS NOW ACRS THE PLAINS ADVECT INTO CNTRL MO BEFORE SUNRISE. WL HAVE TO KEEP AN EYE ON THE NEED FOR LLWS LATE TNGT AND EARLY FRI...BUT HGT OF THE LLJ CORE AND GUSTINESS TO SFC WINDS HAVE PRECLUDED ME FROM FORECASTING IT ATTM. GLASS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ST LOUIS MO 1250 PM CDT THU SEP 21 2006 .DISCUSSION... ALREADY GETTING SOME ELEVATED CONVECTION OVR WRN MO IN ZONE OF LOW LVL WAA AND THETA E ADVCTN JUST E OF STG S-SWLY LLJ OVR THE PLAINS. CONVECTION WILL LIKELY WKN AS IT GETS FURTHER E WHERE ATMOSPHERE CONTAINS LESS LOW LVL MOISTURE AND IS MORE STABLE. WILL LIKELY MENTION LOW POPS OVR THE NRN AND WRN PTN OF THE CWA TDA AS MDLS DEPICT INCRSG 850-700 MB WAA OVR THE CWA...PLUS MDLS INDICATE SOME UPR LVL DIVERGENCE MAINLY OVR THE WRN AND NRN PTN OF THE CWA AHD OF MID-UPR LVL LOW MOVG E-NEWD THRU KS. WILL GO ABV PERSISTANCE ON MAX TEMPS TODAY DESPITE MORE MID-HI LVL CLOUDINESS WITH INCRSG S-SELY LOW LVL FLOW ON THE W SIDE OF SFC/850 MB RDG AND AHD OF LOW PRESSURE SYSTEM MOVG E-NEWD THRU WRN KS. MUCH GREATER CHC OF SHRA/TSRA TGT AS NAM MDL DEPICTS STG 850 MB WAA...THETA E ADVCTN AND MOISTURE CNVG OVR MUCH OF THE CWA ON NOSE OF 60 KT SLY LLJ AHD OF 850 MB LOW OVR SERN NEBRASKA. MAY BE A BRK IN THE MORE WIDESPREAD CONVECTION ON FRI AS WRMFNT MOVS N OF THE CWA...BUT WILL STILL LIKELY HAVE SCT CONVECTION WITH PLENTY OF INSTABILITY OVR THE CWA BY FRI AFTN AND AT LEAST WK FRCG FOR CONVECTION. MORE UNCERTAINTY ON TIMING OF PCPN FRI NGT AND SAT AS MDL SOLUTIONS DIVERGE. WILL PROBABLY GO WITH LIKELY POPS AGAIN FRI NGT WITH THE NAM SHOWING A STG S-SWLY LLJ OVR THE CWA AGAIN AND A CDFNT SLOWLY PUSHING SEWD INTO THE CWA. WILL CONT LIKELY POPS ON SAT MAINLY OVR THE SRN AND ERN PTN OF THE CWA AS THE CDFNT MOVES SLOWLY SEWD THRU THE CWA. MOST OF THE CONVECTION SHOULD SHIFT S AND E OF THE CWA ON SAT NGT AS THE CDFNT FINALLY PUSHES SE OF THE CWA AHD OF SEWD ADVANCING MID-UPR LVL TROF. GKS && .AVIATION... FOR THE 18Z TAFS...RAIN SHIELD OVER WRN MO AND ERN KS IS MAKING SLOW EWD PROGRESS DUE TO DRIER AIR ACROSS ERN MO AND WRN IL. THIS PCPN IS OCCURRING IN ADVANCE OF A RATHER POTENT SHRTWV TROF CURRENTLY LOCATED FROM THE UPR LOW IN WRN KS SWD THRU WRN OK. THIS SHRTWV SHOULD CONTINUE TO LIFT NEWD THIS AFTERNOON AND TONIGHT ACCOMPANIED BY THE AFOREMENTIONED RAIN SHIELD. HOW QUICKLY IT SPREADS EWD AND HOW MUCH IT HOLDS INTACT IS THE BIGGEST QUESTION. THE NEW FCST IS A BLEND OF EXTRAPOLATION AND THE RUC/NAM...AND THUS SHOULD SEE SOME COVERAGE OF LGT RAIN OR SHRA MOVE FROM WEST TO EAST INTO THE TAF SITES FROM MID-LATE AFTERNOON INTO THE EVENING. RAIN SHOULD BE MAINLY WITH VFR CIGS/VSBYS. AFTER THIS INTIAL BAND OF PCPN THINK THE NEXT WAVE OF PCPN...THIS WAVE CONTAINING TSRA WL PRIMARILY AFFECT THE NW HALF OF MO LATE THIS EVENING OVERNIGHT. SFC WINDS WL HAVE A TENDENCY TO BE GUSTY AND MAY ACTUALLY INCREASE LATER TNGT AS BOTH THE SFC PRESSURE GRADIENT INCREASES AND THE S-SWLY LLJ TRANSLATES EWD. MAY SEE SOME MVFR CIGS NOW ACRS THE PLAINS ADVECT INTO CNTRL MO BEFORE SUNRISE. WL HAVE TO KEEP AN EYE ON THE NEED FOR LLWS LATE TNGT AND EARLY FRI...BUT HGT OF THE LLJ CORE AND GUSTINESS TO SFC WINDS HAVE PRECLUDED ME FROM FORECASTING IT ATTM. GLASS && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 320 PM CDT THU SEP 21 2006 .SHORT TERM...WATER VAPOR LOOP SHOWS THE LOW IN KS HAS OCCLUDED AND NEARLY VERTICALLY STACKED. MODELS WOBBLE THE LOW NORTH-NORTHEAST... DEEPER INTO THE COOL AIR AND WELL REMOVED FROM ANY WARM SOURCE STOPPING IN SD LATE TONIGHT. A LARGE AND INCREASINGLY AREA OF SHOWERS EXTENDING FROM EASTERN NE THROUGH SOUTHERN MN IS MOVING NORTHWARD AND IS LARGELY ASSOCIATED WITH THE STRENGTHENING SHORTWAVE THE GFS SHOWS MOVING NORTH AND ARRIVING INTO SOUTHEAST ND/WEST CENTRAL MN THIS EVENING. ISENTROPIC LIFT IN THE 300-310K LAYER WILL BE FAIRLY PERSISTENT TONIGHT THROUGH FRI NIGHT. SEVERAL TAMDAR SOUNDINGS SHOW MUCH OF THE AREA BECOMING SATURATED ABOVE 850 MB. THIS CONFIRMS THE MODELS RELATIVELY QUICK CLOSURE OF TEMPERATURE/DEW POINT TRACES. WOULD USUALLY SLOW THIS PROCESS DOWN AND SLOW THE ONSET OF PRECIPITATION BUT WILL NOT DO SO THIS TIME. SATURATION PRESSURE DEFICITS OF 10-20 MB WILL ALLOW EVEN A LITTLE LIFT TO SQUEEZE OUT SOME RAIN AS EACH SHORTWAVE ROTATES THROUGH. SO WAS VERY BULLISH ON POPS UNTIL TAPERING OFF MAINLY ON SAT WHEN THERE IS MORE UNCERTAINTY REGARDING FILLING OR MOVING ON OF THE LOW. GFS STILL SHOWS SOME ISENTROPIC LIFT AT 00Z SAT BUT ENDING SHORTLY THEREAFTER. DECIDED AGAINST INCLUSION OF THUNDER FOR THIS EVENING THOUGH RUC DROPS THE SHOWALTER INDEXES TO ZERO NORTH TO AROUND FARGO...BUT RUC SHOWS NO CAPE AT ANY LEVEL AND OTHER MODELS SHOW SHOWALTERS AT +5C OR SO. TEMPERATURES TO VARY LITTLE AT LEAST THE NEXT 36 HOURS AS MODEL SOUNDINGS ARE GENERALLY MOIST ADIABATIC WITH THICK CLOUDS. MORE VARIATION WAS INTRODUCED AS CLOUDS THIN OVER THE WEEKEND BUT MOS LOOKS SOLID. .LONG TERM (MON-THU)... THE EXTENDED PERIOD LOOKS VERY MUCH LIKE A TYPICAL FALL WEATHER PATTERN WITH A LOT OF DAY TO DAY TEMP VARIATION LIKELY. THE OVERALL 500MB PATTERN SETS UP A WESTERN RIDGE AND A DEEPENING GREAT LAKES TROUGH. HPC DISCUSSION MENTIONS AN UNSEASONABLY COLD CANADIAN AIRMASS DOMINATING THE NORTHEAST U.S. BY DAY 7. THE FA WILL REMAIN ON THE WESTERN EDGE OF THIS COLD AIR...BUT EITHER WAY WE ARE LOOKING AT TEMPS DROPPING BELOW NORMAL AFTER WED. PRIOR TO THE COLD FRONTAL PASSAGE...MON/TUE LOOK LIKE WARMER DAYS. DID KEEP A SLIGHT CHANCE OF PCPN ALONG/BEHIND THE FRONT ON WED...AS THE 500MB COLD POOL DROPS SOUTH AND COULD BRING SOME INSTABILITY SHOWERS. && .AVIATION... MAIN CHALLENGE FOR THE KGFK/KFAR/KBJI TAFS WILL BE LOWERING CEILINGS AND WHEN TO START THE RAIN. CEILINGS WILL LOWER FIRST ACROSS THE SOUTH AND GRADUALLY SPREAD NORTH ALONG WITH THE RAIN. THE RAIN WILL BE A PROLONGED EVENT...SO ONCE IT MOVES IN IT WILL STAY A WHILE. && && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GV nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 310 PM CDT THU SEP 21 2006 .DISCUSSION... A POWERFUL UPPER LOW CONTINUES TO MIGRATE SLOWLY EASTWARD ACROSS WESTERN KANSAS THIS AFTERNOON...WITH THIS FEATURE EVENTUALLY EXPECTED TO BECOME NEGATIVELY TILTED AND ACCELERATE TO THE NORTHEAST AS STRONG UPSTREAM HEIGHT FALLS SPREAD SOUTHEASTWARD ACROSS THE NORTHERN ROCKIES. A VERY STRONG WESTERLY MID-LEVEL JET HAS ALLOWED THE DRYLINE TO BECOME MUCH BETTER DEFINED THIS AFTERNOON WHILE MIXING EASTWARD...AND THIS FEATURE IS CURRENTLY LOCATED JUST TO THE NORTHWEST OF THE FORECAST AREA. RESIDUAL MID AND HIGH LEVEL CLOUD COVER FROM MORNING PRECIPITATION WILL CONTINUE TO DISSIPATE THIS AFTERNOON...WHILE THE DRYLINE MIXES EASTWARD INTO AN INCREASINGLY MOIST AND UNSTABLE AIRMASS ACROSS NORTH TEXAS THIS AFTERNOON AND EVENING. SHORT TERM MODEL GUIDANCE FROM THE RUC/WRF/SREF ALL SUGGEST THAT ANY RESIDUAL CONVECTIVE INHIBITION WILL BE OVERCOME BY LOW-LEVEL CONVERGENCE...ALLOWING AT LEAST WIDELY SCATTERED CONVECTION TO DEVELOP LATER THIS AFTERNOON. VERY STRONG WIND FIELDS AT ALL LEVELS AND CORRESPONDINGLY LARGE/CURVED HODOGRAPHS PROGGED IN MODEL POINT FORECAST SOUNDINGS SUGGEST SUPERCELLULAR STORM STRUCTURES...WITH A HIGH RISK OF LARGE HAIL AND DAMAGING WINDS. THE TORNADO THREAT WILL BE HIGHEST WITH STORMS ACROSS THE NORTHERN PORTION OF THE FORECAST AREA...WHERE BOUNDARY LAYER RELATIVE HUMIDITY VALUES WILL BE A BIT HIGHER. EXPECT EVENING CONVECTION TO BE PRIMARILY EAST OF THE I-35 CORRIDOR...AND FOR THIS REASON WILL INCLUDE AN INITIAL PERIOD IN THE FORECAST FOR SCATTERED LATE AFTERNOON CONVECTION ACROSS THE ENTIRE AREA. OTHERWISE...WILL MAINTAIN RED FLAG WARNING FOR THE NORTHWESTERN COUNTIES THROUGH EARLY EVENING. HAVE FORECASTED MINIMUM TEMPERATURES CLOSE TO MAV MOS VALUES...WITH A LARGE SPREAD IN MINIMUM VALUES EXPECTED FROM DRY AIR ACROSS THE NORTHWEST TO VERY MOIST AIR IN PLACE ACROSS THE SOUTHEAST. BY TOMORROW...MODELS ARE IN CLOSE AGREEMENT ON THE DEVELOPMENT OF A LARGE UPPER LOW OVER THE NORTHERN PLAINS...AS INITIAL VORT MAX MOVES NORTHWARD TOWARD THE UPPER MISSISSIPPI VALLEY WHILE ANOTHER STRONG VORT MAX MOVES ACROSS THE FOUR CORNERS AND SOUTHERN ROCKIES. THERE IS A SMALL CHANCE THAT REMNANTS OF NOCTURNAL CONVECTION OVER THE MID SOUTH MAY LINGER ACROSS THE FAR EASTERN COUNTIES OF THE FORECAST AREA THROUGH THE DAY...BUT GENERALLY FEEL THAT MOST LOCATIONS WILL BE WINDY...HOT...AND DRY...AS BOUNDARY LAYER FLOW SLOWLY VEERS TO SOUTH-SOUTHWEST. A RED FLAG WARNING WILL LIKELY BE NEEDED FOR MUCH OF THE WESTERN HALF OF NORTH TEXAS ON FRIDAY AFTERNOON GIVEN THESE CONDITIONS...AND A WIND ADVISORY MAY ALSO BE NEEDED BUT THIS APPEARS TO MARGINAL TO BE ISSUED AT THIS TIME. BY EARLY SATURDAY MORNING... THE DEEPENING UPPER LOW OVER THE NORTHERN PLAINS WILL ALLOW A COLD FRONT TO APPROACH THE NORTHWEST PART OF TEXAS. EXPECT PRECIPITATION CHANCES TO INCREASE DRAMATICALLY ON FRIDAY NIGHT/SATURDAY MORNING ACROSS THE NORTHEASTERN COUNTIES...AS LOW-LEVEL JET INCREASES CONVERGENCE AHEAD OF THE SOUTHWARD MOVING FRONT. HIGH CHANCES FOR THUNDERSTORMS WILL CONTINUE ON SATURDAY...AND HAVE INCREASED POPS WITH GOOD SPATIAL CONSISTENCY AMONG THE NAM/GFS/UKMET/CMC. PRECIPITATION WILL END FROM NORTHWEST TO SOUTHEAST BY LATE SATURDAY AS COLD FRONT CONTINUES TO MOVE SOUTHWARD...WITH ONLY LINGERING SHOWERS POSSIBLE ACROSS THE SOUTHERN COUNTIES ON SUNDAY MORNING. IN THE EXTENDED FORECAST...A PLEASANTLY COOL AND DRY PACIFIC AIRMASS WILL BE IN PLACE ACROSS NORTH TEXAS ON SUNDAY AND MONDAY...WITH HIGHS EXPECTED TO FALL BACK INTO THE 80S AND LOWS LIKELY DIPPING INTO THE 50S. GUIDANCE FROM THE ECMWF/GFSLR INDICATE THAT RETURN FLOW WILL BEGIN BY TUESDAY...AS A WEAK CUTOFF UPPER LOW EJECTS EASTWARD ACROSS THE SOUTHERN ROCKIES. MOISTURE RETURN WILL BE SLOW TO OCCUR...BUT DEWPOINT VALUES ARE EXPECTED TO INCREASE AS THIS SYSTEM APPROACHES AND A WEAK COLD FRONT APPROACHES FROM THE NORTH. HAVE INCLUDED SLIGHT CHANCE POPS FOR THE END OF THE FORECAST PERIOD...AND WILL AWAIT STRONGER AGREEMENT ON QUALITY OF MOISTURE RETURN BEFORE INCREASING THEM. && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 73 97 77 91 / 20 0 20 40 WACO, TX 75 98 77 94 / 10 0 0 40 PARIS, TX 72 90 72 90 / 40 20 30 40 DENTON, TX 71 97 74 90 / 20 0 20 40 MCKINNEY, TX 72 94 72 91 / 30 0 30 40 DALLAS, TX 74 96 77 91 / 20 0 20 40 TERRELL, TX 73 92 72 92 / 30 10 20 40 CORSICANA, TX 74 93 75 93 / 20 10 10 40 TEMPLE, TX 75 98 77 95 / 0 0 0 40 && .FWD WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 6 PM THURSDAY FOR TXZ091-TXZ092-TXZ100- TXZ101-TXZ102-TXZ115-TXZ116-TXZ117-TXZ129. TORNADO WATCH UNTIL MIDNIGHT FRIDAY FOR TXZ091-TXZ092-TXZ093- TXZ094-TXZ095-TXZ100-TXZ101-TXZ102-TXZ103-TXZ104-TXZ105-TXZ106- TXZ107-TXZ115-TXZ116-TXZ117-TXZ118-TXZ119-TXZ120-TXZ121-TXZ122- TXZ123-TXZ131-TXZ133-TXZ134. && $$ 65/DD tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN ANGELO TX 1215 PM CDT THU SEP 21 2006 .AVIATION... PRIMARY AVIATION WEATHER CONCERN OVER WEST CENTRAL TX REMAINS WIND. BASED ON AREA WSR88D VAD WIND PROFILERS...EXPECT MAXIMUM SURFACE SPEEDS HAVE BEEN REACHED...BUT DIRECTIONS WILL GRADUALLY VEER TO THE WEST/SOUTHWEST DURING THE AFTERNOON. EXPECT AREAS OF BLOWING DUST CURRENTLY AFFECTING THE KLBB AREA TO REMAIN TO THE NORTH OF KABI. OTHERWISE...WINDS WILL DECREASE THIS EVENING TO 10 TO 15 KTS WITH VFR CONDITIONS PREVAILING. 14 && .PREV DISCUSSION... (ISSUED 1008 AM CDT THU SEP 21 2006) UPDATE... MID MORNING GOES WATER VAPOR IMAGERY SHOWED A DEEP CLOSED UPPER LOW NEAR THE WESTERN OK PANHANDLE...WITH A DRY SLOT ROUNDING THE BASE OF THE UPPER LOW INTO WEST TX. THIS DRYSLOT WAS QUITE IMPRESSIVE ON THE 12Z AMA SOUNDING. FURTHER SOUTH...12Z MAF SOUNDING NOT NEARLY AS DRY. AS IS EXPECTED IN SUCH A WELL MIXED LOWER ATMOSPHERE...SURFACE DEWPOINTS REFLECTED THE LOW LEVEL MOISTURE DISPARITY ON THE MORNING SOUNDINGS. DEWPOINTS UPSTREAM OF WEST CENTRAL TX WERE IN THE 50S OVER FAR WEST TX...WHILE 30 DEGREE DEWPOINTS WERE WORKING EAST FROM EAST CENTRAL NM...INTO THE TX PANHANDLE AND SOUTH PLAINS. THE 12Z NAM MODEL APPEARED TO HAVE A GOOD HANDLE ON LOW LEVEL DEWPOINTS. SLIGHTLY BETTER MOISTURE NOTWITHSTANDING...RAIN CHANCES FOR WEST CENTRAL TX HAVE DECREASED SIGNIFICANTLY FROM EARLIER THIS MORNING. MAY SEE SOME SOUTHWARD EXTENSION OF SHOWERS INTO THE NORTHERN BIG COUNTRY WITH THE APPROACH OF THE UPPER LOW...AND HAVE CONTINUED 20 POPS OVER THESE AREAS. FUEL MOISTURE CRITERIA REMAINS MARGINAL...BUT RED FLAG WARNING CONTINUES FOR AREAS ROUGHLY WEST OF AN OZONA TO THROCKMORTON LINE. CERTAIN LIVE FUELS SUCH AS JUNIPER AND CEDAR MAY BE AT HEIGHTENED RISK OF IGNITION IF ENOUGH PREHEATING CAN OCCUR. 14 PREV DISCUSSION... (ISSUED 654 AM CDT THU SEP 21 2006) AVIATION... LOW LEVEL JET SHOWING UP AT KSJT AND KDYX RADARS WITH VAD WINDS OF 45 AND 50 KTS RESPECTIVELY. KEPT MENTION OF LOW LEVEL WIND SHEAR UNTIL 15Z...EVEN THOUGH A BAND OF LIGHT SHOWERS JUST THE EAST OF ABILENE AND SAN ANGELO HAS MIXED OUT THE ATMOSPHERE SOMEWHAT WITH GUSTS UP TO 25 MPH. MID LEVEL CLOUDS SHOULD MOVE EAST OF KABI AND KSJT BY 15Z. MAY SEE SOME LOW LEVEL CLOUDS 1200 TO 1500 FEET AGL IN SOUTHERN SECTIONS OF CWA...NEAR SONORA AND JUNCTION UNTIL 15-16Z. STRONG SURFACE WINDS WILL BE THE MAIN PROBLEM FOR AVIATION TODAY WITH A STRONG SURFACE LOW OVER SOUTHEAST COLORADO. SURFACE WINDS SHOULD DECOUPLE AROUND 23Z. MAY TEMPORARILY SEE SOME LLWS PROBLEMS AGAIN DUE TO STRONGER WINDS ALOFT...BUT GFS INDICATING A 30 KT LOW LEVEL JET AT THAT TIME...TO WILL LEAVE OUT OF TAFS FOR NOW. LATER SHIFTS HOWEVER WILL NEED TO REEVALUATE LLWS IF WINDS ALOFT DO NOT DECREASE QUITE AS FAST. PREV DISCUSSION... (ISSUED 531 AM CDT THU SEP 21 2006) UPDATE... WILL UPDATE TO EXPAND SLIGHT CHANCE POPS TO THE SOUTHEASTERN COUNTIES FOR THIS MORNING AS ACTIVITY HAS PICKED UP SOUTH OF THE CONCHO VALLEY EARLY THIS MORNING. 20 PREV DISCUSSION... (ISSUED 354 AM CDT THU SEP 21 2006) SHORT TERM(TODAY-FRIDAY)... INTENSE UPPER LEVEL SHORTWAVE THIS MORNING OVER MOVING ACROSS NM. THIS SHORTWAVE IS GOING TO BRING STRONG WINDS AND WARMER TEMPERATURES TODAY. THERE IS A SLIGHT CHANCE THIS MORNING FOR TSRA ACROSS THE NORTHERN AREAS...BUT MAIN HAZARD TODAY WILL BE THE WINDS WITH THE SYSTEM. 700MB WINDS ACCORDING TO RUC ANALYSIS THIS MORNING ARE 40- 50KT...SO HAVE KEPT THE WIND ADVISORY UP THIS MORNING FOR THE CONCHO VALLEY NORTHWARD...AND LAKE WIND ADVISORY FOR CONCHO AND MCCULLOCH COUNTIES. ALTHOUGH FUELS ARE GREEN RIGHT NOW...HAVE GONE AHEAD WITH THE RED FLAG WARNING FOR TODAY AS AREA GRASSES WILL QUICKLY DRY OUT WITH THE HEAT AND STRONG WINDS...AS WELL AS A FIRE WEATHER WATCH FOR TOMORROW AS WE WILL ONLY GET HOTTER...AND DRIER. WINDS WILL BE THE MAIN QUESTION FOR TOMORROW AS FAR AS ANY RED FLAG WARNINGS. HAVE KEPT A SLIGHT CHANCE FOR THE NORTHERN HALF OF THE CWA THIS MORNING...AND DROPPED POPS CONSIDERABLY DURING THE AFTERNOON AS DRY WESTERLY WINDS WILL BE MOVING IN AS WELL AS DRY AIR IN THE MID AND UPPER LEVELS. FOR FRIDAY...WILL KEEP THE FORECAST DRY AND WINDY WITH AN INCREASE IN AFTERNOON HIGH TEMPERATURES TO THE MID 90S. ANOTHER SHORTWAVE WILL DIVE SOUTH INTO THE SOUTHERN ROCKIES ON FRIDAY RESULTING IN SIMILAR CONDITIONS FRIDAY...WITH WEAKER WINDS. LONG TERM... BY SATURDAY...A COLD FRONT WILL BE MAKING ITS WAY SOUTH INTO THE BIG COUNTRY AREA AS ANOTHER SHORTWAVE ROUNDS THE UPPER LEVEL TROUGH OVER THE SOUTHERN ROCKIES AND EJECTS TO THE NORTHEAST. WILL KEEP SLIGHT CHANCE SHOWERS AND THUNDERSTORMS FOR SOUTHEASTERN COUNTIES FOR FRIDAY NIGHT THROUGH SATURDAY...AND THEN ALONG THE FRONT FOR SATURDAY NIGHT INTO SUNDAY SOUTH OF THE CONCHO VALLEY. WE ARE CLIPPED BY SPC/S SLIGHT RISK ON SATURDAY/SATURDAY NIGHT...BUT MAIN ACTIVITY FOR THIS RISK AREA WILL BE WELL EAST OF THE CWA. HOWEVER...THE FRONT WILL BE INTERACTING WITH MOIST UNSTABLE AIR OVER SOUTH TEXAS WHICH COULD RESULT IN SOME STRONG THUNDERSTORMS FOR THE NORTHWEST HILL COUNTRY. AFTER SUNDAY...MAINLY DRY AND COOLER WEATHER IS EXPECTED BEHIND THE FRONT AS SURFACE HIGH PRESSURE DOMINATES OUR WEATHER WITH NORTHWEST FLOW TRANSITIONING TO UPPER LEVEL RIDGING OVER THE CWA BY WEDNESDAY. SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. $$ SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. $$ SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING FROM 1 PM THURSDAY TO 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION... JONES...NOLAN...STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. $$ && .SJT WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...FISHER...HASKELL...IRION... JONES...NOLAN...RUNNELS...SHACKELFORD...STERLING...TAYLOR... THROCKMORTON...AND TOM GREEN. RED FLAG WARNING UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: COKE...CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN... STERLING...TAYLOR...THROCKMORTON...AND TOM GREEN. FIRE WEATHER WATCH FROM NOON FRIDAY TO 6 PM FRIDAY FOR THE FOLLOWING ZONES: BROWN...CALLAHAN...COKE...COLEMAN...CONCHO... CROCKETT...FISHER...HASKELL...IRION...JONES...NOLAN...RUNNELS... SCHLEICHER...SHACKELFORD...STERLING...TAYLOR...THROCKMORTON... AND TOM GREEN. LAKE WIND ADVISORY UNTIL 7 PM THURSDAY FOR THE FOLLOWING ZONES: CONCHO...AND MCCULLOCH. && $$ 99/99/99 tx