AREA FORECAST DISCUSSION...CORRECTED THE DATE NATIONAL WEATHER SERVICE MARQUETTE MI 1140 AM EST SAT DEC 15 2001 MAIN CONCERN THIS FCST PACKAGE IS THE TEMPS TDA...AND INCR CLD CVR TNGT. WV IMAGERY AND RUC DEPICTING RDG OVR W GRTLKS...TRAPPED BTWN A CUTOFF LOW OVR N UT...AND A SHRTWV OVR ERN GRTLKS. MRNG SOUNDINGS SHOWING A SPLIT JET FLOW. ONE MOVING FM NM N ACRS THE HI PLAINS INTO CAN PRARIES...THEN E ACRS ONT. THE OTHER UPR LVL JET RUN ACRS SRN PLAINS THEN E THRU THE S OH VALLEY. A SFC LOW CONT TO DVLP OVR NE CO THIS AM...ALONG WITH A CDFNT WHICH STRETCHES ACRS SRN HI PLAINS. A LOW LVL 40KT JET STRETCHES FM CNTRL TX...N THRU CNTRL PLAINS TO MN THIS AM...AND WAS DRAWING WRM MOIST GULF AIR INTO UPR MS VALLEY. ALREADY SFC DWPNTS ARE INTO LOW 30S ACRS MN. A WEAK SHRTW WILL BE EXPELLED FM THE TROF OVR SW CONUS INTO W GRTLKS TDA. THE MEAN SFC-500MB RH WILL REMAIN LESS THAN 50 PCT OVR THE REGION THRU 00Z SUN. RUC 290K ISENTROPIC ANLYS SHOWING WEAK LIFT OVR THE FCST AREA THIS AFTN. HOWEVER...850-500MB Q-VEC ANLYS SHOWING NEUTRAL LIFT. VIS IMAGERY DEPICTING AN EXTENSIVE LYR OF CLDS ACRS WI EDGING OVR THE U.P. SFC ANLYS AND IR INDCT THESE CLDS TO BE A SHALLOW LOW CLDS. RAOB INDICT THAT THESE CLDS WOULD BE BLO THE INVRN ARND 950MB. SOUNDING DATA SHOWING THE LYR SHOULD DRY OUT ENOUGH FOR THE CLDS TO DISSIPATE BY EARLY AFTN. HOWEVER...SHORTLY AFT THAT...CI/AC WILL FLOW BACK OVR THE U.P. ALREADY THESE CLDS ARE SHOWING UP OVR IA...IL AND SW WI. THEREFORE...THERE SHOULD BE MIX OF SUN AND CLDS THIS AFTN...WHICH WILL LIMIT SFC HEATING. TEMPS ARE A LTL COOLER THAN MDLS SHOW. WILL BUMP TEMPS DOWN A BIT. CDFNT WILL SLIDE INTO MN...AND CONT TO DRAW WARM GULF MSTR INTO THE UPR GRTLKS....WHICH WILL SATURATE OUT THE LOW LVLS. Q-VEC CVNGNC WILL INCR ACRS THE FCST AREA OVRNGT. 290K ISENTROPIC ANLYS SHOWING ASENT IN THE LOW LVLS ACRS U.P. TNGT. THUS SOUNDING DATA INDICATES THAT THE MID LVL CLDS WILL THICKEN OVRNGT. THE CLDS SHOULD KEEP THE TEMPS UP OVRNGT. WINDS WILL REMAIN OUT OF THE S...AND INCR OVRNGT. .MQT...NONE. DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 600 AM EDT SAT DEC 15 2001 MAIN FOCUS THIS PKG DEALS WITH -RA CHCS SUN INTO SUN NIGHT...OTHERWISE THE USUAL CLD/TEMP FCST AGONIES. WV IMAGERY AND RUC ANALYSIS INDICATED A TROF OVER THE WRN CONUS AND RDGG TOWARD THE PLAINS AND MIDWEST. WELL-DEFINED SHRTWV AND 100 KT 3H JET MAX ROUNDING BASE OF UPR TROF OVR SW STATES WHILE MORE SHEARED OUT SHRTWV EVIDENT OVR THE NRN ROCKIES. AT SFC...HIGH PRES RDG OVR THE CNTRL GRT LAKES WHILE LOW PRES IN LEE OF CO RCKYS. SOMEWHAT MOIST SSE FLOW BTWN THESE FEATURES RESULTING IN AREAS OF UPSLOPE STRATUS OVR NCNTRL AND ERN ZONES OF U.P. TODAY...WITH CONTINUED SSE FLOW EXPECT STRATUS CLDS TO HOLD IN OVER ERN ZONES PER 06Z ETA FCST SNDGS. NCNTRL ZONES COULD SEE SOME EROSION OF STRATUS LATE THIS MORNING/ERY AFT WITH DIURNAL MIXING AND A SLIGHT VEERING OF WNDS TO S AHD OF APPROACHING SHEARED OUT CDFNT OVR NRN PLAINS. WRN FA SHOULD STAY FREE OF STRATUS BUT WILL CONTINUE TO SEE WAA CLDS SPILLING OVR RDG AXIS. DRY ADIABATIC MIXING TO 925 MB SEEMS REASONABLE DESPITE HIGH CLDS. THIS WOULD YIELD TEMPS NEAR HIGHER MAV VALUES OF 35 TO 40. SATURDAY NIGHT...STRENGTHENING SLY LLVL JET TO 40 KTS SHOULD BRING IN LLVL MSTR THIS EVENING...SO WENT INCREASING CLOUDS ACROSS FA. DESPITE WK LIFT/Q-VECT CONV AHD OF APPROACHING TROF...MSTR TOO SHALLOW FOR PCPN SO LEFT FCST DRY. STGR WINDS AND MIXING SHOULD KEEP MOST TEMPS ABV FREEZING AGAIN MORE IN LINE WITH AVN GUIDANCE. SUNDAY INTO SUNDAY NIGHT...CONTINUED MOISTURE ADVECTION ALONG WITH MODERATE 700-300 QVECTOR CONVERGENCE AND INCRG 295-300K ISENTROPIC ASCENT AHD OF SHRTWV AND ASSOC SFC CDFNT...WL BE ENOUGH TO KEEP LIKELY PCPN CHANCES FOR CNTRL AND ERN ZONES. TRIMMMED BACK WRN ZONES TO CHC POPS AS ISENTROPIC LIFT NOT AS IMPRESSIVE THERE. ALSO GIVEN MODELS TRENDING SLOWER WITH SHRTWV...BACKED OFF ON TIMING OF -RA THIS AFT SUN. ASSOC SFC CDFNT TENDS TO STALL OUT OR SLOW DOWN SUN NIGHT AS SHRTWV FIGHTS INTO UPR RDG...PER AVN MODEL. DESPITE LOSS OF BEST ISENTROPIC ASCENT...LEFT IN GOING CHC POPS FOR WEST AND CNTRL ZONES AND LIKELY FOR EAST GIVEN FAIRLY DEEP MSTR TO 7KFT AND PROMIXITY OF SFC CDFNT. MONDAY...DESPITE GENL LOSS OF Q-VECT CONV...LINGERING MOISTURE ON MONDAY PER AVN SNDGS AND PRESENCE OF SFC-850 MB OVR AREA...LEFT IN CLDS AND FLURRIES. SUSPECT FLURRIES SHOULD END IN AFT AS SFC-850 MB FLOW BCMS MORE ANTICYCLONIC WITH RDG BLDG IN FM WEST. .MQT...NONE. VOSS mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SPRINGFIELD MO 945 AM CST SAT DEC 15 2001 CLOUD COVER MORE EXTENSIVE THIS MORNING THAN PREVIOUSLY THOUGHT. THIS IS REFLECTED IN THE TEMPERATURE FIELD WITH READINGS STILL IN THE LOW 40S...WITH A FEW MID 40S IN SOUTH CENTRAL MISSOURI. WITH THE INCREASING LOW LEVEL MOISTURE THIS AFTERNOON AND HARDLY ANY BREAKS IN THE OVERCAST...BELIEVE TEMPERATURES WILL BE 45 TO 50 DEGREES AT BEST...WITH THE HIGHEST READINGS OVER SOUTHEAST KANSAS...WHERE THE DEPTH OF THE CLOUD COVER IS LESS. LATEST 20KM RUC STILL INDICATES STRONG THETA-E ADVECTION AND QPF VALUES INCREASING BETWEEN 21-00Z THIS AFTERNOON. ALSO ADJUSTED OVERNIGHT LOWS TO REFLECT DEW POINTS RISING THROUGH THE NIGHT AND ABUNDANT RAINFALL ACROSS THE AREA. NO OTHER CHANGES MADE TO FORECAST. UPDATED ISC GRIDS ALREADY SENT. .SGF... MO...NONE. KS...NONE. JLT mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 248 PM CST SAT DEC 15 2001 FORECAST CHALLENGES -- PRECIPITATION CHANCES TONIGHT SYNOPSIS -- 20Z SURFACE ANALYSIS HAD A LOW OVER NERN CO WITH AN ATTENDANT COLD FRONT STRETCHED FROM CNTRL ND TO ERN NM. PRESSURE FALLS TO THE E OF THIS FEATURE WERE RESULTING IN STRONG, S WINDS ACROSS THE ERN PLAINS STATES. ALOFT, MORNING UPPER-AIR ANALYSIS AND AFTERNOON MOISTURE CHANNEL IMAGERY INDICATED A DIGGING TROUGH OVER THE ROCKIES, WITH A BRANCHED DOWNSTREAM JET STRUCTURE: ONE AXIS FROM WRN NM TO ERN MT, AND THE OTHER FROM CHIHUAHUA MEXICO, ACROSS TX TO THE CAROLINAS. FORECAST -- ETA DIAGNOSTICS SUGGEST THE UPPER-LEVEL TROUGH TO OUR W WILL WEAKEN OVERNIGHT AS IT SLOWLY TRANSLATES ACROSS THE PLAINS. ALTHOUGH RUCII DATA INDICATES STEEPENING MID-LEVEL LAPSE RATES APPROACHING FROM THE SW (~7.0 TO 7.5 DEG C/KM), ONLY WEAK LARGE-SCALE ASCENT IS FORECAST (AS SEEN IN THE Q-VECTOR FIELDS) WITH SHALLOW SATURATION IN THE LOW- AND UPPER-LEVELS OF THE ETA FORECAST SOUNDINGS. THUS, WE WILL CARRY A SLIGHT CHANCE POPS ACROSS ALL BUT FAR SERN ZONES, WHERE WE WILL KEEP 30 PERCENT GOING. OTHERWISE, INCREASING CLOUDS SHOULD KEEP TEMPERATURES UP TO NEAR GUIDANCE VALUES. ON SUNDAY, WE MAY SEE SOME LINGERING LIGHT RAIN OR SNOW IN THE MORNING ACROSS THE ERN ZONES WITH THE PASSAGE OF THE SURFACE FRONT. THE AIRMASS BEHIND THIS FRONT ISN'T ALL THAT COLD, AND WITH INSOLATION INCREASING BY AFTERNOON, WE HAVE OPTED TO GO CLOSER TO THE WARMER MAV VALUES. THE MID-LEVEL FLOW BEGINS TO FLATTEN ON MONDAY AND TUESDAY WITH DOWNSLOPING, LOW-LEVEL TRAJECTORIES SUPPORTING A WARMUP. WE WILL SEE THE PASSAGE OF A WEAK FRONT TUESDAY NIGHT AND WEDNESDAY, WITH A SLIGHT COOL DOWN, THEN RIDGING THROUGH THE END OF THE WEEK, AHEAD OF THE NEXT SYSTEM MOVING ONTO THE W COAST. WE WILL CONTINUE WITH A DRY FORECAST THROUGH THE EXTENDED WITH TEMPERATURES CLOSE TO MEX VALUES. THANKS TO LBF FOR COORDINATION! .OMA...NONE. MEAD ne SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 213 PM CST SAT DEC 15 2001 ATTENTION IN THE SHORT TERM IS POPS TONIGHT. PRETTY STRONG UPPER LEVEL TROUGH MOVING OUT OF THE INTERMOUNTAIN WEST. EARLY THIS EVENING...STRONG GRADIENT WILL HOLD WINDS IN THE BREEZY/WINDY CATEGORY EASTERN ZONES. ALSO...SURGE OF 40 DEGREE DEWPOINTS COMING RIGHT UP THE I-135 CORRIDOR AND TAKING DEAD AIM ON EASTERN HALF OF CWFA. M-ETA AND RUC SUGGEST RAPID INFILTRATION OR FORMATION OF CLOUDS AS MOISTURE INCREASING AND WARM ADVECTION SETS UP FOR A TIME THIS EVENING. THIS WILL AFFECT LOWS TONIGHT...AND HAVE HELD THEM UP A BIT IN THE EAST...AND ANTICIPATE THE TEMPERATURES TO DROP JUST BEFORE SUNRISE AS FROPA OCCURS THERE. THE RISK OF MEASURABLE PRECIPITATION LOOKS VERY SMALL TONIGHT. AGEOSTROPHIC ENHANCEMENT NOT FAVORABLE BY LATE EVENING...ISENTROPIC LIFT IS SHORT LIVED...AND MOISTURE IS PRETTY LIMITED. WHAT/S THERE IS VERY SHALLOW. SPLIT TYPE TROUGH FOCUSES ENERGY TO OUR NORTH AND SOUTH...AND LEAVES US IN BETWEEN. HAVE DROPPED ZFP POP WORDING AND WENT PROVERBIAL SPRINKLES/FLURRIES WORDING. AVN HANGS ON TO CLOUDS TOMORROW LONGER THAN THE ETA. DECIDED TO DELAY CLEARING WORDING JUST A BIT. CLOUDS AND COLD ADVECTION WILL DEFINITELY TAKE TEMPERATURES LOWER. THROUGH THE FIRST 15 DAYS OF DECEMBER...WE ARE AVERAGING ABOUT 13 DEGREES ABOVE. THIS GENERAL IDEA WILL CONTINUE THROUGH MOST OF DAYS 2 THROUGH 7...WITH MONDAY/S WEST WINDS AND SUNSHINE EXPECTED TO PUSH TEMPERATURES IN THE 50S MANY AREAS. COOLER AIR AND CLOUDS TUESDAY WILL HOLD TEMPERATURES DOWN SOME...BUT STILL ABOVE NORMALS. COOLEST DAY IS WEDNESDAY BUT SUNSHINE LOOKS LIKELY. RIDGING AHEAD OF DIGGING WEST COAST TROUGH SUGGESTS WARMER WEATHER THURSDAY AND FRIDAY...AND CURRENT 40S IN THE FORECAST MAY NOT DUE. MRF EJECTS WAVE SATURDAY AND AND WARM ADVECTION ASSERTS ITSELF. THE RESULT IS PRECIPITATION CENTERED JUST TO OUR SOUTHEAST. UNCERTAINTY AT THIS TIME...ALONG WITH APPROACHING TRAVEL HOLIDAY...LEAD ME TO HOLD OFF ON PRECIPITATION... AND WAIT FOR SOME MORE CONTINUITY TO DEVELOP. AFTER DAY 7...THE DEVELOPMENT OF STRONG RIDGE NEAR WEST COAST WILL BE A KEY PLAYER IN DETERMINING HOW THINGS WILL SHAKE OUT OVER HOLIDAYS. .GID...NONE. MORITZ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BISMARCK ND 305 PM CST SAT DEC 15 2001 WL MAKE SOME CHANGES TO EARLY PTN FCST AS SLOWER MVMT OF TROF CURRENTLY INTO CNTRL ND HAS RESULTED IN SOME TIMING PROBLEMS AND INCG MOISTURE WL RESULT IN SOME PCPN OVER WRN AND CNTRL ND THROUGH EARLY SUNDAY. THERE ARE SOME MDL DIFFERENCES BUT HAVE SETTLED ON 18Z MESOETA FOR DETAILS. THIS IS PRETTY SIMILAR IN PLACEMENT OF 70H TROF COMPARED TO LATEST RUC...BUT NOT QUITE AS DEEP...AND IS ALSO WEAKER THAN 12Z RUNS OF ETA/AVN. IN THE WEST THIS EVENG CONCERN IS THAT MID LVLS OF ATMS HAVE NOT COOLED OFF ENOUGH THAT ENTIRE COLUMN IS BELOW FREEZING. THUS AS SFC TEMPS DROP BELOW FREEZING EARLY THIS EVENING ANY HYDROMETEORS REACHING THE GROUND MAY BE IN THE FORM OF FREEZING RAIN. ATTIM NO REPORTS TO CONFIRM/DENY THOUGHT BUT MAY MENTION SOME FREEZING SPRINKLES WRN ZONES THIS EVNG. HOPEFULLY COLUMN SHLD HAVE COOLED ENOUGH THAT BY TIME PCPN REACHES CNTRL ND PCPN WL BE ALL SNOW. AMOUNTS WL BE LGT AND WL GO CAT POPS ONLY FOR NERN ZONES...FM MOT EWD...AND MENTION AMTS LESS THAN AN INCH. WL STICK WITH POPS ELSEWHERE ACROSS CNTRL ZONES FOR NOW...AND ONLY FLURRIES/PSBL FREEZING SPRINKLES WEST. WL ALSO MENTION SOME LINGERING FLURRIES FAR ERN ZONES SUN MRNG. ANOTHER PROBLEM MAY BE AREAS OF FOG SO WL MENTION FOG FOR AREAS ALONG AND EAST OF CURRENT TROF POSN. LOW CLOUDS WL KEEP TEMPS WARMER THAN PREV FCST OVER CNTRL AND ERN ZONES SO RAISED OVER NIGHT LOWS THESE AREAS. BEYOND FIRST AND EARLY SECOND PDS LTTL OR NO CHANGES TO GOING FCST. MILD WORDING ON MONDAY LOOKS GOOD AS UPR RDG BUILDS OVER RGN WITH GOOD WLY FLOW AS SFC LOW REMAINS WELL NORTH OF AREA. IN THE EXTENDED...GENERALLY ZONAL FLOW WITH SERIES OF WK IMPULSES THROUGH PD. PERHAPS A LTL MORE SIG TROF IND BY MRF FOR FRI-SAT PD BUT WITH UNCERTAINTY IN FAST ZONAL FLOW WILL KEEP A DRY FCST THROUGH EXTENDED PD. .BIS...NONE. TWH nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 929 PM EST SAT DEC 15 2001 SATELLITE IMAGERY THIS EVENING SHOWS SCATTERED MID AND HIGH LEVEL CLOUDS AFFECTING AREAS NEAR THE TENNESSEE BORDER. WILL NOT ISSUE AN UPDATE TO THE ZONES THIS EVENING...AS THEY ARE IN FINE SHAPE. WILL...HOWEVER...REISSUE THE RDF...SINCE TEMPERATURES AND DEWPOINTS IN SOME ZONES ARE OFF JUST A LITTLE BIT. LATEST RUC RUN STILL SUPPORTS DRIER AIR FILTERING INTO THE FORECAST AREA OVERNIGHT. FCSTID = 44 GSP 39 55 42 53 / 0 0 30 50 AND 39 55 42 53 / 0 0 30 50 CLT 38 53 40 53 / 0 0 30 40 HKY 35 50 38 53 / 0 0 30 50 AVL 33 51 39 54 / 0 0 40 50 .GSP... GA...NONE. NC...NONE. SC...NONE. BURRUS sc AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 1015 AM MST SAT DEC 15 2001 CDFNT SLOWLY SLIDING THROUGH SRN HALF OF CWFA ATTM. THE UPPER TROF AND POST FRONTAL PCPN STILL W OF CWFA...AND THE TENDENCY HAS BEEN TO SLOW ITS EWD MOVEMENT. 12Z ETA/15Z RUC NOT IMPRESSIVE WITH EITHER OMEGA OR RH FIELDS ACRS CWFA...REALLY NOT MUCH TO GET EXCITED ABOUT. THUS HAVE LOWERED POPS AND PUSHED BACK PCPN TIMING TO EXTEND INTO 'TONIGHT' PD. LOW FROUDE NUMBERS AND LACK OF RH SHOULD KEEP UPSLOPE SNOW OVER THE NRN HILLS TO A MINIMUM. WITH SLOWER PROGRESSION OF TROF...STRONGER WINDS WILL CONTINUE INTO THIS EVENING ACRS SD ZONES. HOWEVER...MAX 850MB WINDS OF 35-40KTS SHOULD KEEP WINDS BELOW ADVISORY CRITERIA. .UNR...NONE. JOHNSON sd SOUTHEAST TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 903 AM CST SAT DEC 15 2001 WIDESPREAD CLOUDCOVER AND STRONG SOUTH TO SOUTHEAST LOW LEVEL WINDS DRAGGING ABUNDANT MOISTURE INTO THE AREA. PW AROUND THE AREA RUNNING 1.5 TO 1.75" AT 00Z. GPS HAS PW 1.75 AT PALESTINE WITH 1000- 500 MB THICKNESSES OF 565-567--FAR EXCEEDING THE 70% SATURATION THICKNESS VALUES AND ALSO HAS THE STEEPER LAPSE RATES IN THIS AREA AS WELL. SW JET RIPPING OUT OF MEXICO AT 125-140 KNOTS FROM WEST OF DRT TO NE OK. WATER VAPOR IMAGES INDICATE ANOTHER RIPPLE ALOFT MOVING TOWARD THE DRT AREA AND RADAR OUT OF EWX APPEARS TO SUPPORT THIS AS WELL. 00Z RUC HAS A 140 KNOT MAXWIND SMALL JETLET OVER DRT AT 12Z. THIS IS LEADING TO THE LIKELIHOOD THAT PRECIPITATION SHOULD REMAIN WEST OF THE FA OR ELSE IN THE FAR WEST/NORTHWEST FA. WILL LOWER POPS IN THE NORTH AND CENTRAL FA. WARM FRONT HAS MOVED PAST CLL AND DEWPOINTS IN THE MID TO UPPER 60S COVER MOST OF THE FA WITH SOUTHERN HALF OF FA NEAR 70. WARM FRONT SHOULD LIFT MUCH FURTHER NORTH. WILL NUDGE UP TEMPERATURES IN THE NORTHERN FA AND SHOW NEAR STEADY TEMPERATURES OVER THE FA TONIGHT. SHOULDN'T SET ANY RECORD HIGH MINS AFTER THE COOL START TO THE DAY. FORECAST FOR SUNDAY LOOKS ON TRACK WITH HIGH POPS AREA WIDE AND THE EXPECTATION OF A LINE OF THUNDERSTORMS DEVELOPING FURTHER S FROM PRESENT OVER THE HILL COUNTRY AND SWEEPING EAST. MAY EVEN GET SOME TO DEVELOP POST FRONTAL OVER THE FAR NORTHERN ZONES WITH LOW EJECTING OUT-STEEP LAPSE RATES-RESIDUAL MOISTURE AND VIGOROUS LIFT. WILL LET THE NEXT SHIFT MAKE THAT CALL WITH MORE MODEL DATA TO PERUSE. NO CHANGES PLANNED FOR THE MARINE. HAVE TO AGREE WITH PREV DISC--WOULD NOT BE AT ALL SURPRISED TO SEE 2001 BECOME THE WETTEST YEAR EVER FOR HOUSTON AFTER TONIGHT'S/TOMORROW'S STORMS AND THE ACTIVITY EXPECTED NEXT WEEKEND/EARLY NEXT WEEK. SEE PNSHOU FOR MORE DETAILS. -- 45/31/D .HGX...SCEC ALL WATERS TONIGHT. UPDATED PRELIMS... CLL TU 065/070 042/061 037 583 STEADY TEMPS LOWERED POPS IAH TU 068/076 045/063 040 385 STEADY TEMPS LOWERED POPS GLS EU 069/075 054/062 048 386 STEADY TEMPS tx DEEP SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 925 AM CST SAT DEC 15 2001 DATA FROM MORNING RADIOSONDE LAUNCH SHOWS SIG WARMING BLO 600MB...ABT 11 DEG C AT 925MB...OVR PAST 24 HRS. LI NOW BLO ZERO AT -2.1 AS AIR HAS BECOME VERY MOIST BLO 5K FT... WITH CI DECK ARND 25K FT. WINDS BTWN 2 AND 5K FT ARE 25-40KTS WITH VAD WIND PROFILE VERY SIMILAR. WV/IR SATELLITE LOOP HAS MID/UPR LVL MOISTURE STREAMING ACRS MEXICO TOWARD THE MID MISSISSIPPI VALLEY IN FLOW DOWNSTREAM OF THE L/WV TROF CROSSING THE ROCKIES. BRO RADAR IN REFLECTIVITY MODE DETECTING SHOWERS AND LIGHT RAIN OVER THE CWA...INCLUDING THE COASTAL WATERS. SEE NO NEED TO CHANGE MORNING PACKAGE FOR NOW. MARINE...RUC DATA SHOWS THE MODERATE PGF PERSISTING OVER THE GULF WATERS THROUGH THE REST OF TODAY WITH DECENT 7H LIFT AND MOISTURE EVIDENT THROUGH 00Z THIS EVENING. ACCORDINGLY...WILL MAINTAIN A MENTION OF ISOLD SHOWERS THROUGHOUT THE DAY. BUOY020 CURRENTLY IS REPORTING WINDS NEAR 15 KT WITH GUSTS TO 19 AND SWELLS NEAR 4 FT. HAVE AMENDED THE CURRENT CWF TO INCREASE SURFACE WINDS AND SWELLS A BIT OFFSHORE. OTHERWISE...NO OTHER CHANGES REQUIRED ATTM. SYNOPTIC-PUBLIC...59 MARINE-AVIATION...60/62 MESO...DW INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO .BRO...NONE. tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 300 AM CST SUN DEC 16 2001 MAIN CONCERNS IS THE POTENTIALLY FLOODING ACROSS SOUTH CENTRAL AND SOUTHEAST ILLINOIS LATEST 06Z SURFACE ANALYSIS DEMONSTRATES SURFACE LOW ACROSS NORTHERN PLAINS STATES WITH ANOTHER ACROSS TEXAS. SURFACE WARM FRONT WAS ACROSS GULF COAST REGION. SURFACE COLD FRONT WAS ACROSS PLAINS STATES. LATEST 0715Z IR SATELLITE IMAGE DEMONSTRATED PLENTY OF CLOUDS ACROSS EASTERN PLAINS STATES INTO THE MS VALLEY. LATEST 0715Z W/V IMAGE SHOWS S/WS ACROSS PLAINS STATES...ANOTHER STRONG S/W ACROSS ARIZONA...AND ANOTHER S/W APPROACHING PACIFIC NORTHWEST. MODELS WERE FAIRLY SIMILAR WITH THE MAIN FEATURES. MODELS HAD DIFFERENCES WITH TIMING AND STRENGTH OF THE FEATURES. AVN HAS BEEN MORE CONSISTENT AND PREFER AVN OVERALL. AVN MOVES TROUGH IN THE ROCKIES EAST ACROSS THE UPPER MIDWEST INTO THE MS VALLEY BY 12Z MON. AVN THEN SHIFTS TROUGH EAST ACROSS EASTERN U.S. BY 12Z TUE. AVN DEVELOPS SURFACE LOW OUT OF TEXAS AND STRENGTHENS IT AS IT MOVES NORTHEAST TO JUST EAST OF EVV BY 12Z MON. AVN CONTINUES TO STRENGTHEN AND MOVE LOW NORTHEAST ALONG THE EAST COAST BY 12Z TUE. AVN PLACES SOUTHEAST ILLINOIS AT THE NOSE OF A 50KT LOW LEVEL JET BY 00Z MON AND THEN SHIFTS IT EAST BY 12Z MON. AVN DEVELOPS 130KT 300MB JET ACROSS UPPER MIDWEST SOUTH INTO EASTERN PLAINS STATES BY 00Z MON...THEN SHIFTS IT EAST ACROSS GREAT LAKES REGION SOUTH INTO MS VALLEY BY 12Z MON. AVN THEN MOVES 120KT 300MB JET EAST INTO THE EAST COAST BY 06Z TUE. AVN...ETA...AND RUC MODEL SOUNDINGS AND DATA CURRENTLY POINT TO ALL LIQUID PRECIPITATION ACROSS CWA NEXT 24 TO 36 HRS. MODEL SOUNDINGS INCREASE PWS TO 1 TO 1.25 IN THROUGH 12Z MON. TRACK OF LOW AND TIMING CRUCIAL WITH PRECIPITATION. AVN T/H CROSS SECTIONS PLACES HIGH MID AND LOW LEVEL MOISTURE ACROSS CWA THROUGH 03Z TUE THEN DECREASES IT BY 12Z TUE. AVN 300K ISENTROPIC SURFACE PLACES SOME ISENTROPIC LIFT AND COND PRES DEF ACROSS CWA THRU 06Z MON AND THEN SHIFTS EAST OF CWA. WILL EXTENDED FFA ACROSS SOUTHEAST CWA INTO MONDAY WITH FFG LOW AND PRECIPITATION GOING INTO MONDAY. EXTENDED LOOKS GOOD...HOWEVER AVN PLACES PRECIPITATION LATE TUESDAY NIGHT INTO WEDNESDAY. THANKS FOR COORDINATION DVN. ...PRELIMINARY CCF NUMBERS FOR COORD PURPOSES ONLY... SPI RR 048/042 043/033 045 13+++ PIA RR 048/040 043/032 044 13+++ DEC RR 048/042 044/033 045 13+++ CMI RR 047/043 045/032 044 13+++ MTO RR 048/043 046/033 045 13+++ LWV RR 050/047 049/034 046 13+++ .ILX...FLOOD WATCH SOUTH OF I-70 TODAY...TONIGHT...AND MONDAY ILZ062-063-066>068-071>073 $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1112 AM EDT SUN DEC 16 2001 TME MAIN CONCERN FOR THIS FCST PACKAGE IS -RA THIS AFTN AND TONIGHT. WV IMAGERY AND RUC DEPICTING A RDG FM JAMES BAY TO FA...A LOW OVR SW NM WITH AN ASSOC TROF XTND N ACRS N PLAINS...AND A TROF OVR E PAC. A SFC LOW IS OVR THE LAKE OF WOODS WITH AN ASSOC CDFNT RUNNING S ACRS UPR MS VALLEY INTO THE S PLAINS. A SFC RDG IS XTND ALONG THE APPALACHIANS MTNS. THESE TWO SYS CONT TO DRAW WARM MOIST GULF AIR INTO THE UPR GRTLKS. ANOTHER RDG IS BUILDING OVR FOUR CORNERS AREA. SFC DWPNTS ALREADY IN THE MID 30S ACRS FCST AREA THIS AM. THE SFC LOW WILL CLIMB INTO W ONT THIS AFTN DRAGGING THE CDFNT INTO W LK SUPERIOR...AS THE UPR LVL TROF SLIDES TO NR WCPL. THE TROF WILL XTND SW INTO CNTRL PLAINS. WEAK SHRTWV ENERGY WILL WANDER THRU FCST AREA BY LATE AFTN. 290K ISENTROPIC ANLYS SHOWING WEAK LIFT OVR THE CWA AHEAD OF THIS FRNTL BOUNDARY. Q-VEC CONVERGENCE WILL INCREASE ACRS THE UPR GRTLKS AS WELL THIS AFTN. MEAN SFC-500MB RH WILL RISE TO >90 PCT ACRS THE UPR GRTLKS THIS AFTN. WITH THE INCR LIFT AND ABUNDANCE OF MSTR ACRS CWA THIS AFTN...THE DZ WILL CHG OVR TO -RA. TEMPS WILL CHG LTL WITH THE -RA AND CLD CVR. MESO-ETA TEMP PROFILE SHOWING SFC BASE INVRN THRU AFTN...FOR ALL LOCATIONS XPCT E CWA. THUS DO NOT XPC THE STRONGER WNDS TO MIX TO SFC...SO WNDS WILL BE LTL LGTR THAN XPC OVR W AND CNTRL CWA. CURRENT OBS BARE THIS OUT. THE SFC LOW OVR W ONT WILL TRACK TO NE ONT BY 12Z MON DRAGGING THE CDFNT THRU THE CWA. THE SHRTWV WILL BE ACRS CNTRL U.P. BY 12Z...AND THE ENERGY WILL BE FOCUSED OVR E CWA. ISENTROPIC ANLYS CONT TO SHOW WEAK LIFT AHEAD OF THE FNT...AND STRONGEST Q-VEC CONVERGENCE WILL BE OVR EASTERN ONT BY 12Z. DRY AIR ADVECTING WILL LOWER THE MEAN SFC-500MB RH TO < 50 PCT OVR W U.P. OVRNGT. THUS COND LOOK AS IF IT WILL GRAD IMPROVE OVRNGT FM W TO E. SFC BASED INVRN WILL LIFT TO ARND 900MB BY 12Z. THE PRES GRADIENTS WILL WEAKEN SO THE WNDS WILL REMAIN LGT AND SHIFT W. DRY COND WILL REMAIN OVR THE FCST AREA ON MON. THE LVL BLO 900MB INVRN WILL REMAIN QUITE MOIST. THUS XPC TO SEE LOW CLDS ON MON...BUT NO PCPN IN THE W. ENOUGH LOW LVL MSTR WILL REMAIN IN PLACE OVR THE E CWA BLO THE INVRN WHICH SHOULD GENERATE SPRINKLES AND/OR FG. CLD CVR WILL CONT TO MODERATE THE TEMPS AND WINDS WILL STAY <15MPH WITH WEAK GRAD. .MQT...NONE. DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1100 AM EST SUN DEC 16 2001 ...UPDATED TO FRESHEN WORDING OF AFTERNOON ZONES... LITTLE QUESTION RAIN IS ON THE WAY. THE ONLY REAL QUESTION IS WHEN? THE UPDATES ZONES HAVE TAKEN THE RAIN OUT OF THE NORTHEAST CWA FOR THE AFTERNOON BUT KEEP SCATTERED SHOWERS IN THE NORTHWEST CWA AND BRING RAIN INTO THE SOUTHERN CWA BY EVENING. THE WATER VAPOR LOOP SHOWS A TROPICAL PLUM OF MOISTURE HEADING NORTH FROM THE GULF TO THE CANADIAN BORDER. THE MORNING PRECIPITABLE WATER ANAL FROM NCEP SHOWS VALUES BETWEEN 150 AND 220 PERCENT OF NORMAL JUST SOUTH OF MICHIGAN AT 12Z. AS I WRITE THIS THERE IS A NICE SFC TO 850 THTE RIDGE AIMED AT SOUTHWEST MICHIGAN. HELPING THAT IS THE ENTRANCE REGION OF A 130 TO 140 KNOT 300 MB JET AND THE ASSOCIATED SHORTWAVE OVER IL/MO/IO. THE REGIONAL RADAR MOSAIC TWO AREAS OF RAIN TO WATCH. FIRST IS AN AREA OF SCATTERED SHOWERS ASSOCIATED WITH THE NRN STREAM SHORTWAVE. THAT IS MOVING NORTHEAST WITH THE ASSOCIATED SHORT WAVE. SECOND IS THE LARGE AREA OF SOLID RAIN MOVING NORTH WITH THE SOUTHERN SYSTEM. AT 1530Z THAT IS AS FAR NORTH AS EAST CENTRAL IL. THE NEGATIVE TO THE RAIN IS A LARGE MID LEVEL DRY LAYER... TYPICAL OF THIS SORT OF WEATHER PATTERN. THAT IS SHOWN WELL ON THE DTX 12Z SOUNDING. HOWEVER... LOOKING AT THE GRB SOUNDING IT IS CLEAR THAT DRY AIR WILL BE OVERCOME THE ISENTROPIC LIFT...MOISTURE CONVERGENCE AND JET LIFT. THAT IS SHOWN NICELY BY THE NGM...ETA...AVN... RUC AND CANADIAN GLOBAL AND REGIONAL MODELS. HOWEVER... SEEMS THE NORTHEAST CWA WILL REMAIN TO DRY THROUGH 00Z TO SEE ANY RAIN SO I SEPARATED THAT ZONE GROUP OUT AND JUST WENT WITH A CLOUDY SKY FORECAST THERE. ELSEWHERE... HAVE SCATTERED SHOWERS OVER THE NORTHWEST AND WEST CENTRAL CWA FOR THE SHOWERS FROM THE TAIL OF THE NORTHERN STREAM SHORTWAVE AND THE INCREASING MOISTURE PLUM FROM THE SOUTHERN SYSTEM. OVER THE SOUTHERN CWA... RAIN WILL DEVELOP THERE AFTER 400 PM... SO RAIN LIKELY BY EVENING SEEMS FINE THERE. ZONES ARE ALREADY OUT. .GRR...NONE. WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1035 AM EST SUN DEC 16 2001 WAA/ISENTROPIC SHRA CONTINUES TO INCREASE IN AREAL COVERAGE ACROSS WI AND NRN IL LATE THIS MORNING...WITH A LARGE AREA OF STEADY RAIN STEADILY PUSHING NORTH THRU CENTRAL IL AND IN WHERE LOW LEVELS HAVE SUFFICIENTLY MOISTENED. ACROSS OUR CWA...LOW LEVELS REMAIN DRY... WITH MAJORITY OF REGIONAL OBS REPORTING BKN-OVC MID CLOUD. LATEST TREND ON KAPX BASE REFLECTIVITY CONFIRMS THE PRESENCE OF MID CLOUDS/VIRGA. GOING FORECAST IS HANDLING THE SITUATION WELL. RUC AND MESOETA STILL SUGGESTS LOW LEVELS WILL MOISTEN FROM W TO E DURING THE AFTERNOON...WITH BEST CHANCE OF PRECIP ACROSS NW LWR MI AS THE AFTERNOON PROGRESSES. WILL UPDATE MAINLY TO REMOVE MORNING WORDING...BUT WILL MAINTAIN THE OVERALL FLAVOR OF THE FORECAST WITH RESPECT TO LIKELY POPS SW TAPERING TO CHANCE POPS NE. WILL ALSO MAKE MINOR WORDING ADJUSTMENTS TO BOTH TEMP AND WIND FORECAST. .APX...NONE. EME mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 557 AM EDT SUN DEC 16 2001 FOCUS THIS PKG IS OVERRUNNING -RA EVENT TODAY AND TONIGHT...MAINLY FOR CNTRL AND ERN ZONES...AND AS USUAL CLDS/TEMPS REST OF PDS. WV LOOP/RUC ANALYSIS SHOWS UPR RDG OVR ERN CONUS WITH TROF OVR THE WRN CONUS. BTWN THESE FEATURES...SW FLOW ALLOWING MSTR PLUME TO LIFT INTO THE WRN GRT LAKES. VIGOROUS SRN STREAM SHRTWV ROUNDING BASE OF UPR TROF OVR SWRN STATES WHILE SHEARED OUT NRN STREAM SHRTWV MOVG THRU ERN DKTAS. .TODAY...STGR SRN STREAM SHRTWV AND ASSOC DVLPG SFC LOW LIFTS INTO LWR MIDWEST TONIGHT AND OH VALLEY MONDAY...HAVING LTL EFFECT ON U.P. WX. HWVR...A WEAKER PIECE OF ENERGY EJECTS OUT OF BASE OF UPR TROF AHD OF MAIN WAVE AND THIS DOES BRUSH CNTRL AND ERN U.P. LATER THIS AFT. MODELS INDICATE DECENT 295-300K ISENTROPIC LIFT AND MOISTENING OUT AHD OF THIS WKR WAVE. ALREADY SEEING SOME AREAS OF DRIZZLE DVLP OVR NCNTRL ZONES DUE TO WK 850-500 MB Q-VECT CONV AND SHALLOW LYR OF MOIST AIR BLO STG SUBSIDENCE INV. MUCH OF ISENTROPIC LIFT INITIALLY WL GO INTO MOISTENING VERY DRY COLUMN OF AIR IN PLACE...EVIDENT PER 00Z AREA SNDGS. DESPITE DRIER AIR...CONDENSATION PRES DEFICITS DO LWR TO 10-20 MB BTWN 18-00Z OVR ERN HALF ZONES. THUS...KEPT MENTION OF AREAS OF RAIN DVLPG EAST WITH GENL TAPERING OFF TO SPRINKLES OVR WRN ZONES WHERE ISENTROPIC LIFT NOT IMPRESSIVE AT ALL. BUMPED UP MAXES TO LWR 40S MOST ZONES AS WND AND CLDS ALLOWING MINS TO START OFF FM MID TO UPPER 30S. .TONIGHT...NRN STREAM SHRTWV TROF MOVES IN FM WEST PUSHING ASSOC NRN PLAINS WK CDFNT INTO AREA. ETA HAS COME AROUND TO MORE AVN SOLN WITH SLOWER PROGRESSION OF NRN STREAM SHRTWV/ASSOC CDFNT THRU RDG. CONTINUED WK ISENTROPIC ASCENT AND HINT OF RRQ FORCING FM 130 KT 3H JET MAX LIFTING OVR CNTRL U.P. WL JUSTIFY LIKELY POPS OVR FAR ERN ZONES. CNTRL ZONES...LEFT JUST CHC POPS AS UPR FORCING WKR...WHILE JUST EXPECT SPRINKLES WEST. WENT MORE IN LINE WITH WARMER AVN MOS GIVEN CLD CVR EXPECTED OVR AREA AND DWPNTS LINGERING IN MID 30S. .MONDAY...SHRTWV AND ASSOC CDFNT EXITS TO EAST AS LLVL FLOW BCMS MORE DIFLUENT AND ANTICYCLONIC BEHIND IT. KEPT SOME LINGERING MORNING SPRINKLES IN FOR 4 ERN COUNTIES...WHILE REST OF ZONES SHOULD STAY DRY. EXPECT CLDS TO HOLD IN WITH ONSHORE NNW FLOW AND WK CAA SO DO NOT EXPECT MUCH OF REBOUND IN TEMPS...AGAIN MORE IN LINE WITH AVN MOS. .MONDAY NIGHT INTO TUESDAY...GOOD DNVA/RDGG BLDG IN FM WEST MONDAY NIGHT WHILE SFC WNDS BACK TO WEST LATE. INTRODUCED SOME PARTIAL CLRG OVERNIGHT FOR WRN AND CNTRL ZONES...BUT KEPT EAST MSTLY CLDY WITH ONSHORE NW FLOW. WINDS BACK MORE WLY ON TUE FOR FAR ERN ZONES SO WORDED SOME PARTIAL CLRG THEN. FOLLOWED MAV GUIDANCE TEMPS WHICH SEEMED REASONABLE. .MQT...NONE. VOSS mi FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 95O AM CST SUN DEC 16 2001 FORECAST CONCERN FOR UPDATE MAINLY CLOUD TRENDS...PCPN AND TEMPS. SFC LOW LIFTING INTO EXTREME SOUTHEAST MANITOBA WITH N/S COLD FRONT ALONG A ROX-BWP LINE. ASSOCIATED POST FRONTAL WRAP-AROUND BAND OF PCPN NEARLY CONFINED TO FAR NW MN. AREAL COVERAGE DECREASING FROM KMVX-88D AND CLOUD TOPS WARMING FROM IR LOOP. ISOLD SPRINKLES AHEAD OF BOUNDARY SHOWING UP ON METARS. 850MB TEMPS AND 1000-850 THICKNESS SUPPORT MAINLY -SN IN MAIN PCPN ZONE. WITH DECREASING TREND MEASURABLE PCPN WILL BE MINIMAL AND ONLY A DUSTING FOR SNOW ACCUMULATIONS. FARTHER SOUTH WOULD ONLY EXPECT A FEW FLURRIES OR SPRINKLES AND WILL ADJUST WORDING ACCORDINGLY. COLD ADVECTION MINIMAL SO TEMPS LIKELY TO DROP OFF SLIGHTLY THEN HOLD FAIRLY STEADY IN WAKE OF COLD FRONT. RUC HAS A REASONABLE HANDLE ON CLOUD TRENDS WITH CLEARING LINE WORKING INTO CENTRAL ND ATTM. NW FORECAST AREA WILL SEE BREAKS THIS AFTERNOON WITH MOST AREAS HOLDING IN THE CLOUDS UNTIL MAINLY THIS EVENING. .FGF...NONE. VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 405 PM EDT SUN DEC 16 2001 12Z RAOBS/LATEST WV LOOP AND RUC ANAL SHOW PERSISTENT HI AMPLITUDE RDG OVR THE E WITH A TROF OVR CNTRL NAMERICA WITH A NUMBER OF OUT OF PHASE SHRTWVS EMBEDDED WITHIN. BUT SINCE INTENSE VORTEX/ARCTIC AIR NOTED OVR AK WITH LO PRES ACRS WRN CAN...AIR UNDER CNTRL TROF IS PACIFIC IN ORIGIN AND NOT VERY COLD AT ALL. WV LOOP SHOWS MSTR PLUME IN ADVANCE OF UPR TROF HAS ADVCTD INTO NW GRT LKS WITH PW UP TO AN INCH AS FAR N AS SRN WI AT 12Z...AND 120KT SWLY H3 UPR JET HAS ENHANCED MSTR TRANSPORT. CLOSEST SHRTWV WITHIN CNTRL TROF IS MOVG INTO SW ONTARIO NOW AND SUPPORTS 1008MB SFC LO N OF INL. ATTENDANT COLD FNT MOVG INTO NW WI. AIR BEHIND THIS FNT IS ONLY MARGINALLY CHILLY WITH WEAK SFC RDG GRDLY BRKG UP LO CLD OVR NRN PLAINS AS LINGERING LLVL MSTR GIVES WAY TO SFC DWPTS IN THE TEENS FARTHER W. BACK EDGE OF DEEP MSTR NOW MOVG INTO WRN CWA...JUST AHD OF SFC COLD FNT. 12Z MPX/ABR SDNGS DEPICT LLVL MSTR UNDER MID LVL DRYING/ SUBSIDENCE INVRN H85-9. CLD TOP TEMPS HAVE INCRSD SINCE THIS MRNG WITHIN WARM CONVEYOR BELT AHD OF FNT AS SHRTWV BECMG INCRSGLY SHEARED AS IT MOVES INTO ERN RDG...AND DRY SURGE AT H7 PUSHES TOWARD LK SUP. COMPOSITE 88DS/SFC OBS INDICATE SCT SHRA IN CNTRL ZNS PUSHING E. JUST SOME -DZ FARTHER W TO COLD FNT. AIRMASS OVR NW LKS UNSEASONABLY MILD WITH TEMPS 35 TO 45...SO ALL PCPN RA. SFC DWPTS AS HI AS 40 UP TO SRN CWA...AND PTCHY FOG ALSO NOTED. MAIN FCST CONCERNS THIS PACKAGE ARE PCPN COVG/TIMING TNGT IN ADVANCE OF ONTARIO SHRTWV AND THEN CLD/TEMPS MON AND TUE AS WEAKENING CNTRL PLAINS TROF MOVES E OF CWA AND MORE ZONAL PACIFIC FLOW DOMINATES. FOR TNGT...AVN/ETA/NGM SHOW UPR DRYING WITH WARM CONVEYOR BELT AXIS SHIFTING STEADILY E SO THAT PW UNDER 0.5 OVR ENTIRE CWA SHORTLY AFTR 06Z EVEN THOUGH SOME UPR DVGC LINGERS AS H3 JET MOVES OVHD. SFC FNT NOT PROGGED TO CLR ERY UTNIL ABOUT 12Z...SO UPR DRYING MOVES OUT IN FNT OF LLVL DRYING. AS DEEP MSTR/UPR DVGC EXIT TNGT W TO E...XPCT LINGERING SHRA TO TAPER OFF TO -DZ. SINCE LLVL DRY PUSH BEHIND FNT IS MODEST AT BEST...XPCT AREAS OF FOG TO PERSIST UNDER UPR DRYING. THERE MAY BE SOME CLRG OVR FAR W AS SFC RDG AXIS/LWR DWPTS APRCH TOWARD 12Z. XPCT MIN TEMPS CLOSER TO HIER MAV GUIDANCE PER OBSVD HI DWPTS AND UPSTREAM MINS SUN MRNG. SFC RDG AXIS PROGGED TO MOVE INTO CWA ON MON. LLVL DRY AIR FCST TO GRDLY OVRSPRD ENTIRE CWA...BUT MORE NEUTRAL FLOW/ETA FCST SDNGS AND FWC/MAV MOS GUIDANCE SUG LO CLD WL PERSIST ALL DAY ACRS THE ERN ZNS WITH MORE OF A NNWLY FLOW OFF LK SUP HELPING MAINTAIN CLDS UNDER 3K FT INVRN. REST OF CWA WL SEE AT LEAST SOME CLRG WITH MORE OF A WLY ACYC FLOW. MOS FCST TEMPS LOOK RSNBL PER UPSTREAM OBS IN THE NRN PLAINS THIS AFTN. WEAK UPR/SFC RDG TO BE IN PLACE MON NGT...BUT ETA/AVN SHOW SOME ISENTROPIC LIFT DVLPG AFTR MIDNGT AS LGT SW FLOW DVLPS BTWN DEPARTING SFC RDG TO THE E AND ANOTHER SHRTWV MOVG E THRU CNTRL CAN. BUT QUITE A DISCREPANCY BTWN RH FCSTS AS AVN SHOWS QUITE A BIT MORE MOISTENING THAN ETA. CONSIDERING MID/UPR DRYNESS OF INCOMING AIR MASS AND WEAK ISENTROPIC LIFT FCST...WL TEND TOWARD THE DRIER ETA IDEA AND GO JUST PCLDY OR BCMG PCLDY OVR THE W PER FCST RH/TIME SECTIONS THAT SHOW INCRSG MID LVL RH. CLDS OVR THE E SHUD CLR IN THE EVNG AS SFC RDG AXIS PASSES. HAVE TENDED TOWARD LWR FWC GUIDANCE FOR MINS GIVEN DWPTS IN THE TEENS OBSVD TDAY IN THE NRN PLAINS. ETA SHOWS AXIS OF HIER MID/UPR RH CROSSES CWA ON TUE IN ADVANCE OF SHRTWV DROPPING SE THRU SCNTRL CAN. WL CALL THE DAY PSUNNY. SINCE RH/TIME SECTIONS SHOW LINGERING DRY AIR...XPCT NO PCPN EVEN AS SFC TROF ASSOCIATED WITH SHRTWV ARRIVES LATE IN THE DAY OVR THE W. CAN SHRTWV AND SFC TROF PASS TUE NGT WITH MODEST CAD PATTERN IN ITS WAKE LATE TUE NGT/WED. RATHER NEUTRAL LOOK TO SFC-H85 FLOW AND H85 TEMPS DOWN TO ONLY ABOUT -10C SUG NO MORE THAN CHCY POPS FOR LES NR LK SUP. 00Z EXTENDED MODELS SHOWING A GRDL WEAKENING OF PERSISTENT HIGH PRES RDG OVR THE SE THRU THE WEEK AS VORTEX OVR SE CAN INTENSIFIES UNDER BLDG UPR HGTS IN GREENLAND. ALTHOUGH INCRSGLY NEGATIVE NAO AND FCST WNWLY UPR FLOW WOULD SUG COLDER AIR IS IN STORE FOR THE NW GRT LKS...SE RDG HAS ENDED UP MORE RESILIENT THAN FCST RECENTLY AND MODELS ALSO HOLD ON TO PERSISTENT VORTEX OVR AK AND LOW PRES OVR WRN CAN/PAC AIR IN CONUS. SO MAIN THEME BY THE END OF THE WEEK WL BE SOMEWHAT LWR TEMPS...BUT NO REAL ARCTIC AIR WITH ABV NORMAL READINGS CONTG. DIFFICULT TO DETERMINE FCST DETAILS AT THIS POINT AS MODELS SHOWING LTL RUN-TO-RUN CONTINUITY AND DIFFERENT TIMING OF SHRTWVS MOVG THRU RATHER ZONAL FLOW...SO CONFIDENCE ON DAY-TO-DAY DETAILS VERY LO. WL MAKE FEW CHGS TO GOING FCST ATTM XCPT TO TREND AWAY FM SHSN ON THU AND TOWARD DRIER DAY SINCE H85 TEMPS APPEAR MARGINAL FOR LES AND COLD INTRUSIONS SHUD BE BRIEF IN RELATIVELY ZONAL FLOW. THINK UKMET IDEA OF A MORE AMPLIFIED TROF IN THE E AT THAT TIME OVERDONE CONSIDERING TENACITY OF ERN RDG AND LACK OF VERY COLD AIR...AND ONLY A SML MINORITY OF CAN/MRF ENSEMBLE MEMBERS SUPPORT UKMET SOLN. COORDINATED WITH APX. .MQT...NONE. KC mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE JACKSON MS 1142 AM CST SUN DEC 16 2001 SATELLITE AND OBS SHOWING BREAKS/THIN SPOTS ARE BECOMING MORE SUBSTANTIAL THAN EXPECTED. LOOKS LIKE TEMPERATURES WILL PUSH 80 DEGREES OVER MANY AREAS AND HAVE HAD TO UPDATE TO RAISE TEMPERATURES A CATEGORY OR TWO MOST PLACES...EXCEPT FAR E WHERE WEDGE CONTINUES TO KEEP TEMPERATURES COOLER. WARMER TEMPERATURES ALSO RESULT IN MORE MIXING WITH MANY LOCATIONS OVER NORTHERN AND WESTERN ZONES REPORTING SUSTAINED 15 KNOT WINDS WITH HIGHER GUSTS. WITH PROFILERS AND VAD WIND PROFILES SHOWING 30 TO 40 KNOT WINDS AT LOWEST GATES INCREASED WINDS AND MENTIONED CAUTION ON LAKES NW AND CENTRAL ZONES WHERE LATEST RUC IS SHOWING STRONGEST LOW LEVEL WINDS FOR AFTERNOON HOURS. PRELIM NUMBERS JAN 78/57/62/40 2930 MEI 73/58/64/39 1870 .JAN... MS...FLOOD WATCH FOR TONIGHT ZONES 018-019-025-026-034 LA...NONE AR...FLOOD WATCH FOR TONIGHT ZONES 074-075 08 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 200 PM CST SUN DEC 16 2001 FORECAST CONCERNS: DURATION OF RAINFALL/CHANCES OF CONVECTION OVERNIGHT AND MONDAY MORNING. ABNORMAL HIGH RAINFALL AMOUNTS FOR MID DECEMBER ACROSS THE REGION AS PRECIPITABLE WATER VALUES NEARLY 200% ABOVE NORMAL. RAINFALL AMOUNTS HAVE BEEN SUBSTANTIAL ACROSS THE AREA WITH AMOUNTS RANGING FROM A QUARTER OF AN INCH IN SOUTHEAST KANSAS...AND FAR WEST CENTRAL MISSOURI...TO OVER TWO INCHES ALONG THE ARKANSAS BORDER FROM BRANSON TO ALTON. ALTHOUGH THUNDERSTORMS HAVE NOT DEVELOPED...THE INCREASING MID LEVEL COOLING AND THE ENHANCED RIGHT ENTRANCE REGION OF THE MAIN JET THIS EVENING WILL PROVIDE ISOLATED THUNDERSTORMS IN SOUTH CENTRAL MISSOURI. LATEST 20/40 KM RUC EVEN INDICATIONS ELEVATED CONVECTION OF AROUND 500 J/KG ACROSS SOUTH CENTRAL MISSOURI THIS EVENING. THIS WILL ONLY AGGRAVATE THE ALREADY INCREASED FLOODING SITUATION ALONG THE ARKANSAS BORDER...SO WILL CONTINUE THE FLOOD WATCH THROUGH MIDNIGHT. MODELS ARE STILL INDICATING BETWEEN ONE AND TWO INCHES OF ADDITIONAL RAINFALL IN THE FAR SOUTHEAST ZONES BY MONDAY MORNING. STRONG DIVERGENCE AND ASSOCIATED LARGE SCALE LIFT OVER THE AREA WILL DECREASE AFTER MIDNIGHT WHICH SHOULD ALLOW FOR THE INTENSITY OF THE RAINFALL TO DIMINISH. HOWEVER STILL BELIEVE ANOTHER ONE TENTH TO ISOLATED ONE HALF INCH OF RAIN MAY FALL IN EXTREME SOUTH CENTRAL MISSOURI. LIGHTER PRECIPITATION SHOULD FALL OVER THE DEFORMATION ZONE MONDAY MORNING BEFORE THE MAIN DYNAMICS MOVES OFF TO THE EAST AND WEAKENS. STILL WARM ENOUGH TEMPERATURES FOR ALL LIQUID PRECIPITATION AS EVEN THE MID LEVEL THICKNESS VALUES ARE WARMER THAN YESTERDAYS MODEL RUNS. NEXT SHORT WAVE ENERGY AND ASSOCIATED COLD FRONT MOVES INTO THE AREA WEDNESDAY...HOWEVER MOISTURE IS LIMITED AND ONLY ALLOWING FOR AN INCREASE IN MID LEVEL CLOUDINESS. HAVE READJUSTED TEMPERATURES DURING THIS TIME FRAME. LATEST ENSEMBLE FORECAST ON THE MRF/AVN STILL INDICATE A CHAOTIC SITUATION NEXT WEEKEND WITH THE LATEST TREND LIMITING THE MOISTURE AND KEEPING MOST OF THE RAINFALL SOUTH OF THE AREA UNTIL SUNDAY. STILL HAVING SOME CONCERNS OF THIS SCENARIO...HOWEVER AS THE PATTERN BEGINS TO CHANGE BY THE WEEKEND...AND THE NORTHERN STREAM BEGINS TO AFFECT THE CENTRAL U.S. IT SEEMS LOGICAL FOR THIS SCENARIO. HOWEVER WILL CONTINUE THE CHANCE OF RAIN FOR SATURDAY AND SUNDAY. NEXT WEEK LOOKS TO BE MUCH COOLER AS THE NORTHERN JET PLAYS MORE OF A ROLE IN THE SENSIBLE WEATHER OVER THE CENTRAL U.S. (LIGHT SNOW CHRISTMAS NIGHT??) ISC GRIDS ALREADY SENT. FCSTID = 25/JLT SGF 40 45 24 52 / 100 60 10 10 JLN 38 48 26 54 / 100 30 10 10 UNO 43 46 23 52 / 100 60 10 10 VIH 40 45 23 53 / 100 60 10 10 .SGF... MO...FLOOD WATCH THROUGH MIDNIGHT FOR ZONES MOZ082>083...MOZ092...MOZ095>098...MOZ103>106. KS...NONE. mo DEEP SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 300 PM CST SUN DEC 16 2001 SFC REPORTS AT MID DAY INDICATED THE PAC FRONT STRETCHED FROM THE DALLAS-FORT WORTH METRO AREA SOUTHWEST TO EAGLE PASS. TEMPERATURES IN WEST TEXAS AND PANHANDLE IN THE UPPER 30S TO MID 40S. BRO RAOB FROM THIS MORNING SHOWED 40KT LLJ AT ABT 1000FT...AFTN HEATING MIXING BEGAN TAPPING THE JET...HENCE GUSTS OVER COASTAL COUNTIES IN THE 30-35MPH RANGE. AFTN PACKAGE W/B REVISED FOR WINDS AND MAY HAVE TO EXTEND INTO TONIGHT. IR SATELLITE LOOP SHOWS MID LVL SHORT WAVE TROF MOVG OVER FAR WEST TEXAS W/DRY SLOT POKING INTO BIG BEND AREA. RUC80 HAS TROF PROGRESSING EAST INTO W TEXAS THIS AFTN..THEN LIFTING NORTHEAST TOWARD THE RED RIVER THIS EVENING...BRINGING NORTHWEST WINDS TO NW SECTION OF CWA THIS EVENING AND THRU SOUTH PADRE ISLAND BY MIDNIGHT. AS MID LVL L/WV TROF MOVES ACRS N TX TONIGHT...WNW FLOW AT H5 BREAKS DOWN TROPICAL CONNECTION AND STARTS DRYING OF ATMOS AT MID LEVELS MON-TUE WITH NORTH WIND AT SFC. AS NEXT S/WV TROF ADVANCES ACRS ROCKIES INTO THE HIGH PLAINS ON TUESDAY...RETURN FLOW OVR DEEP SOUTH TEXAS (DPSOTEX) BEGINS TUE EVENING. BY WED...THE MID LEVEL S/WV TROF CROSSES THE SOUTHERN/CNTRL PLAINS ADVANCES WITH EAST SFC WINDS BACKING TO THE NORTH BY MID DAY WED AS A WEAK PAC FRONT MOVES THRU. BY THURS...HI PRESS CNTR MOVES EAST ACRS TEXAS INTO THE SE U.S. AS NEXT MID LVL TROF MAKES IT OVER THE THE W COAST AND DEEPENS AS IT DROPS DOWN OVR THE DESERT SW. AHD OF THIS S/WV TROF...LOW PRESSURE FORMS OVR THE CNTRL HIGH PLAINS...RESULTING IN A RETURN TO ONSHORE FLOW AT THE SFC OVR DPSOTEX THRU FRI. THE MID LEVEL CLOSED LOW DROPS SE INTO EXTREME NW MEXICO ON SATURDAY...UNTIL ANOTHER S/WV AMPLIFIES AS IT DROPS DOWN FROM W CANADA ACRS THE NORTHERN PLAINS IN THE ZONAL FLOW AND PICKS UP THE CLOSED LOW OVR EXTREME NW MEXICO. BY EARLY SUNDAY...A SFC TROF AHD OF THE MID LEVEL L/WV TROF STRETCHES FROM THE GREAT LAKES DOWN INTO THE BIG BEND AREA OF TEXAS. THIS SYSTEM CONT TO MOVE EAST DURING THE DAY...BRINGING A COLD FRONT TO THE AREA BY EVENING. MARINE... WINDS WILL EASE UP AFTER SUNSET AND WITH APPROACH OF COLD FRONT THIS EVENING...BUT WILL CONTINUE E OVER NORTHERN MEXICO WILL PROVIDE A MODERATE TO STRONG SOUTH WIND OVER THE COASTAL WATERS TODAY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR TODAY AS SEAS INCREASE WITH GUSTY SOUTH WINDS. THE STRONG SOUTH WINDS WILL DIMINISH BY LATE AFTERNOON OR EARLY EVENING...AS A COLD FRONT APPROACHES THE LOWER TEXAS WATERS. THE FRONT WILL PUSH ACROSS THE COASTAL WATERS AROUND MIDNIGHT...BRINGING STRONG NORTHWEST WINDS. SMALL CRAFT ADVISORIES ARE LIKELY TO CONTINUE INTO MONDAY...BEFORE HIGH PRESSURE SETTLES OVER THE AREA. MARINE...AT MID AFTN BUOY020 SHOWS SEAS ARND 7 FT...AND SE WIND AT 20 KTS WITH GUSTS TO 25 KTS AS A RESULT OF SFC TROF OVER TEXAS FROM THE VALLEY NORTH INTO NORTH TEXAS AND MIXING DOWN OF LOW-LEVEL JET BY AFTERNOON HEATING. THE STRONG PGF OVER THE MARINE AREAS WILL CONTINUE THIS EVENING AHEAD OF THE SURFACE FRONT NOW PUSHING INTO SOUTH CENTRAL AND DEEP SOUTH TX. THE GRADIENT WILL NOT DIMINISH LATER TONIGHT AS A STRONG NW FLOW WILL PUSH IN BEHIND THE FRONT. THIS WIND SHIFT WILL KEEP OFFSHORE SWELLS ABOVE SCA LEVELS AS PER THE GWW DATA. CONDITIONS DO NOT WEAKEN UNTIL LATE MONDAY AS THE SURFACE HIGH WEAKENS. THE MESO-ETA LI VALUES REMAIN UNSTABLE OVER THE EASTERNMOST COUNTIES IN THE CWA...THE LAGUNA MADRE AND THE OFFSHORE WATERS THIS EVENING AHEAD OF THE COLD FRONT WITH THE MOST UNSTABLE VALUES REACHING -4 BETWEEN 00 AND 06Z THIS EVENING. SO WILL MAINTAIN THE MENTION OF CONV THIS EVENING ENDING WITH THE FROPA. CONT SCA FOR ALL MARINE ZONES THIS EVENING. PRELIMINARY NUMBERS: BRO BU 056/070 048/075 060 20/00/00/00/00 HRL BU 053/070 047/072 059 20/00/00/00/00 MFE BU 054/070 048/079 056 20/00/00/00/00 RGC BU 050/069 044/074 054 20/00/00/00/00 SPI BU 063/070 057/073 065 20/00/00/00/00 SYNOPTIC...59 / MARINE-AVIATION...60 INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO .BRO...SCA TONIGHT GMZ130-150-155-170-175. WIND ADVISORY THIS EVENING FOR TXZ251-254-255-256-257. tx DEEP SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 1110 AM CST SUN DEC 16 2001 SHORT TERM...VSBL IMAGERY SHOWS PLENTY OF LOW AND MID LEVEL MOISTURE ADVECTING NE TOWARDS E TX AHEAD OF THE 5H LOW OVER W TX/NEW MEX. RUC AND WS-ETA GUIDANCE SHOW LITTLE PVA MOVING OVER THE BRO CWA WITH THE BULK OF THE UPPER LEVEL DYNAMICS CONCENTRATED OVER W AND CENTRAL TX. THIS BULK OF THE PVA PIVOTS AROUND THE BASE OF THE 5H LOW EVENTUALLY KICKING OUT TO THE NE TOWARDS THE RED RIVER VALLEY BY 00Z TONIGHT. MSAS AND THE BRO 12Z SOUNDING MAINTAINS THE BULK OF THE INSTABILITY CONCENTRATED OVER THE COASTAL AREAS AND OFFSHORE WITH INDICATED LIS RANGING FROM -2 TO -4 WITH VALUES >0 OVER THE WESTERN CWA. SO BEST POTENTIAL FOR CONV WILL PERSIST ALONG THE HIGHWAY 77 THIS AFTERNOON. THE PGF WILL PERSIST AHEAD OF THE APPROACHING COLD FRONT WHICH WILL MAINTAIN THE STRONG SOUTH SURFACE FLOW TODAY. DESPITE THE CLD COVER...THE STEADY WAA WILL PUSH AFTERNOON TEMPS TO NEAR MAV TEMP GUIDANCE. CURRENT ZFP WORDING OF 20 % POPS THIS AFTERNOON LOOKS GOOD WITH NO CHANGES NEEDED ATTM. MARINE...THE TIGHT PGF OVER THE BAY AND GULF WATERS WILL KEEP SEAS AGITATED TODAY WITH CONDITIONS STAYING ABOVE SCA CRIT. CONDITIONS WILL NOT IMPROVE MUCH IN THE WAKE OF THE FRONT AS THE NW FLOW BUILDS IN PLACE OVER THE REGION. WILL CONTINUE SCA. SYNOPTIC-MARINE-AVIATION...60/MESO...WATKINS INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO .BRO...SCA TODAY GMZ130-150-155-170-175. tx