SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO COLORADO 128 PM MDT SUN APR 29 2001 MAIN CONCERN TNGT IS POTENTIAL SHRA/TSTM COVERAGE THIS EVE...THEN UNSEASONABLY WARM TEMPS...MAX TEMPS 10-18 DEGS ABOVE AVE...MON THROUGH AT LEAST WED. STILL PLENTY OF UNCERTAINTY ON THE EVOLUTION OF MID-LATE WEEK CLOSED LOW IN THE WRN US. CURRENTLY: LATEST WATER VAPOR IMAGERY/RUC 500-300MB LAYER VORT ANIMATIONS ARE SHOWING ELONGATED CYCLONIC SHEAR AXIS NEAR THE UT/CO BORDER. A LITTLE SLOWER THAN EXPECTED YDA. SHALLOW INSTABILITY CU... MAINLY OVER THE MTNS...HAVE BEEN FEW AND FAR BETWEEN THANKS TO 500MB "DRY" SLOT JUST AHEAD OF THE TROUGH AXIS PER 12Z/29 500MB ANALYSIS AND WATER VAPOR IMAGERY. LEE SIDE TROUGH WAS LOCATED OVER EXTREME SERN CO WITH SFC DEW POINTS IN THE 40S...BUT LOW LEVEL CONVG ZONE IS RELATIVELY WEAK...SO FAR. WITH SFC TEMPS IN THE 80S...40S DEW POINTS...AND SLIGHTLY COOLER 500MB AIR MOVING IN...THIS HAS PROMOTED SBCAPE VALUES OF 400-1500 J/KG AND LIS OF 0 TO -4C PER LAPS PLAN VIEW DATA. A FEW SHRA/TSTM HAVE DEVELOPED IN SERN CO PER RADAR/LIGHTNING DETECTION SYSTEM. TNGT: LATEST 40KM RUC/ETA/MESO-ETA ALL SUGGEST...NOW...THE MAIN 500MB TROUGH AXIS...AND ASSOCIATED 300-200MB PV ANOMALY...WILL NOT MOVE THROUGH ERN 1/2 CO UNTIL AFT 03Z/30 JUST AS AIR MASS STARTS TO STABILIZE. THERE IS A VERY WEAK SHORTWAVE PROGGED JUST AHEAD OF THIS TROUGH AXIS...THOUGH. GIVEN THE VERTICAL THERMAL PROFILE... MOST SHRA/TSRA WOULD BE HIGH BASED PRODUCING LOCAL WIND GUSTS OF 30- 40 MPH AND LITTLE QPF...EXCEPT FOR THE FAR SERN CO PLAINS WHERE THERE IS A LITTLE BETTER LOW LEVEL MOISTURE TO WORK WITH. ALSO GIVEN WET BULB ZERO AROUND 12K FT MSL...PROGGED CAPE VALUES AND LIMITED SPEED SHEAR...ANY OF THE STRONGER TSTMS IN FAR SERN CO COULD PRODUCE 40-50 MPH WIND GUSTS AND MAYBE 1/4-1/2 INCH DIAMETER HAIL AROUND BACA CO. WILL MAKE THE POP/COVERAGE CALL AT PRESS TIME PER RADAR/SATELLITE TRENDS. TROUGH AXIS/300-200MB PV ANOMALY MOVE INTO ERN CO AFT 06Z/30. NOT ANTICIPATING MUCH ACTIVITY PASSED MIDNIGHT AS AIR MASS CONTINUES TO STABILIZE. PERSISTENCE LIKELY THE BEST WAY TO GO WITH MIN TEMPS. MON-MON NGT: MID-UPPER LEVEL WLY FLOW DEVELOPS OVER THE CNTRL ROCKIES WITH 500MB TEMPS WARMING TO -10C TO -12C. HARD TO FIND A SIGNIFICANT SYNOPTIC SCALE SYSTEM COMING THROUGH TO ENHANCE CONVECTION. WITH WARMING MID-LEVELS...AIR MASS SHOULD NOT BE AS UNSTABLE AS IN THE PAST FEW DAYS. MON AFTN BEST LIS PROGGED TO BE 0 TO +2C AND NO CAPE. THERE IS SOME 700MB MOISTURE HANGING AROUND AND COMBINED WITH HIGHER TERRAIN SNOW MELT SHOULD BE ABLE TO GENERATE SOME DIURNAL/INSTABILITY CU OVER THE MTNS. MAX TEMPS OVER THE LOWER ELEVATIONS WILL DEPEND UPON THE DEPTH OF THE MIXED BOUNDARY LAYER. MIXED DRY ADIABATICALLY TO 500MB WOULD YIELD 88F AT 850MB(PUB) AND 79F AT 800MB(COS, ALS) AND COULD SEE 90F IN SERN CO PLAINS. HECK WE'RE PRETTY MUCH THERE RIGHT NOW. FWC FINALLY CAUGHT UP. YDA'S FWC MON MAX FCST WAS 78F...NOW 89F. FWC/MAV ARE FAIRLY SIMILAR...SO WILL STAY CLOSE. 50S/60S IN THE MTNS. MON NGT COULD BE RATHER MILD WITH LEE SIDE TROUGH DEVELOPING IN THE ERN CO...WHICH COULD SET THE STAGE FOR A WARM TUE. TUE-TUE NGT: NRN STREAM SHORTWAVE IS FORECAST TO SEND A SFC COLD THROUGH NRN PLAINS INTO NE BY LATE TUE AFTN. DEEP WLY FLOW DEVELOPS OVER CNTRL ROCKIES. TUE AFTN VERTICAL TEMP PROFILE NEARLY THE SAME AS MON...EXCEPT AVN 700MB TEMPS WARMER...(+14C). TEMPS MAY BE A FEW DEGS WARMER...GIVEN A WARMER START. KLXV(10.2K FT MSL) COULD REACH 60F. MIXING TO 500MB...MAY TAP INTO 20-30KT WINDS...SO WILL KEEP WIND MENTION. MET PATTERN STARTING TO SET UP FOR FRONTAL TYPE MCS MADDOX PATTERN IN CNTRL PLAINS. NOCTURNAL MCS POTENTIAL SHOULD BE IN NE/UPPER MIDWEST...BUT ANY STRONGER OUTFLOW BOUNDARIES COULD "SHOVE" COLD FRONT S-W INTO CWFA. THIS IS LIKELY WHAT THE 66-84HR ETAX IS TRYING TO DO...WHICH LEADS TO THE BIG FCST HEADACHE. EXTENDED(WED-SUN): STILL CONFLICTING MODEL INFORMATION ON MET PATTERN DEVELOPING WED-SAT. ON WED...66-84HR ETA DRIVES SHALLOW SFC COLD FRONT INTO SERN CO WED. TOUGH CALL ON WHERE THE ACTUAL FRONT WILL LIE. IF MESOSCALE SYSTEM DOESN'T DEVELOP...THEN FRONT MAY REMAIN FURTHER N. SHORTWAVE MOVES THROUGH GREAT BASIN WITH ETA DEVELOPING 700MB CLOSED LOW NEAR THE 4-CORNERS AREA AND WAA PATTERN OVER ERN CO...HENCE ALL THE ETA QPF FOR ERN CO WED AFTN. AVN HAS FRONT FURTHER N AND LESS QPF. ETA SUGGESTING WED AFTN TEMPS IN THE 40S/50S ACROSS SERN CO...WHILE AVN SUGGESTING 70S/80S. AGAIN...TOUGH CALL. PLAN TO CONTINUE CURRENT WED FCST UNTIL THERE IS BETTER CONSENSUS... DON'T WANT TO JUMP TO EARLY ON A MESOSCALE SYSTEM. HINTS OF POTENTIAL NOCTURNAL MCS AROUND ERN CO/WRN KS WED NGT...BUT THAT ALL DEPENDS WHERE THE LOW LEVEL FOCAL POINT(BOUNDARY/FRONT) LIES...WHICH IS NEXT TO IMPOSSIBLE THIS FAR OUT. FOR THU-SAT...FOR WHAT I REMEMBER YDA... TRENDS ARE SOMEWHAT SIMILAR...BUT 500MB LOW PLACEMENT/STRENGTH/TIMING ARE DIFFERENT. NOW DROPS LOW INTO NWRN AZ...CAN MODEL HAS IT IN SRN CA...ON THU THEN KIND OF WOBBLES AROUND IN THE GREAT BASIN FRI. MRF STILL WANTS TO FILE THE LOW AND SEND IT ACROSS CO ON SAT. BIGGEST PLAYER FOR POTENTIAL PRECIPITATION MAY BE THE CNTRL US COLD FRONT ON THU. HINTS OF GULF OF MEXICO MOISTURE WIDE OPEN WITH 40S/50S DEW POINTS PROGGED ACROSS SERN CO THU. COMBINED WITH PROGGED 700MB WAA PATTERN...COULD GENERATE STEADY PRECIPITATION. MAY MAINLY BE STRATIFORM PRECIPITATION/LOW CLOUDS FROM SERN CO MTNS/PLAINS. WITH CLOSED W OF CO...COLD AIR NOT IN PLACE AND POTENTIAL SNOW LEVEL WOULD BE AROUND 9-12K FT MSL...UNLESS THERE IS STRONG DIABATIC COOLING. ON FRI...CONCERNED ABOUT RELATIVELY DEEP DRIER AIR MASS MOVING INTO SRN CO AND COULD CUT OFF PRECIPITATION CHANGES..EXCEPT FOR MAYBE SOME -DZ...AS MID-LEVEL "DRY" AIR MIXES INTO THE MATURING CYCLONE. CURRENT THU-SAT TEMPS MAY BE ON THE WARM SIDE IF THIS PATTERN DEVELOPS...WILL TWEAK THEM DOWN A CAT. FOR SUN...WILL PLAY CLIMO AND LEAVE PRECIPITATION MENTION OUT. .PUB...NONE. METZE co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 850 PM EDT SUN APR 29 2001 00 UTC SURFACE ANALYSIS SHOWS A STATIONARY, EAST-WEST ORIENTED FRONT FROM SOUTH CAROLINA TO WEST TENNESSEE. THE 1000-700 MB FLOW IS EAST AT 20 KNOTS ACROSS THE FORECAST AREA, AND A FEW SHOWERS HAVE MADE IT IN FROM THE ATLANTIC. THE UPPER LEVELS ARE GRADUALLY COOLING AND MOISTENING AS A SHORT WAVE APPROACHES FROM THE WEST. IN FACT, THE LATEST RUC FORECASTS Q-G FORCING TO CONTINUE OVER THIS AREA TONIGHT. WITH FAIRLY STRONG LOW LEVEL FLOW OFF THE ATLANTIC, WILL KEEP SLIGHT CHANCE POPS IN THE GEORGIA AND EASTERN BIG BEND ZONES FOR THE REST OF THE NIGHT. OTHERWISE, NO CHANGES ARE EXPECTED FOR THE ZONE FORECASTS. BASED ON THE LATEST RUC AND SURFACE ANALYSIS, I HAVE SOME DOUBTS AS TO WHETHER WE WILL HIT SCA CRITERIA. BUT IT'S CLOSE ENOUGH THAT I AM RELUCTANT TO DROP THEM AT THIS POINT. .TLH... AL...NONE. GA...NONE. FL...FIRE WX WATCH MON AFTN WRN BIG BEND AND EAST PANHANDLE. SCA GMZ750-755-770-775. FOURNIER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 931 AM EDT SUN APR 29 2001 WIDESPREAD ISENTROPIC LIFT OVER NEARLY STALLED FRONTAL SURFACE ACROSS FLA STRAITS INTO GUFMEX HAS PRODUCED CLOUDY SKIES OVER S FLA ALONG WITH AREAS OF LIGHT RAIN. PRECIPITATION TOTALS ARE LESS THEN ONE TENTH OF AN INCH DOWN TO A TRACE OVER MANY AREAS OF S FLA AT THIS TIME AND FORECAST OF HIGH POPS WILL CONTINUE BUT AT THE MOMENT WITH LOW ACCUMULATIONS APPEARING TO BE THE NORM. STILL SEE MODEL DIFFERENCES (LATEST RUC VERSUS 06Z MESOETA AND AVN) ON EVOLUTION OF SYNOPTICS. RUC AND AVN IDENTIFY AND CORRESPOND MORE CLOSELY WITH VORTICITY MAX/CONCENTRATED PRECIPITATION OVER FLA STRAITS SE OF MID KEYS WHILE MESOETA INDICATES MUCH WEAKER SYSTEM. ALL THOUGH BY LATE IN DAY (21Z ON) THAT UPPER VORTICITY TROUGH MOVES OVER EXTREME S FLA (I.E. MIAMI-DADE,MAINLAND MONROE,COLLIER AND BROWARD COUNTIES). WILL UPDATE ZFP PACKAGE TO REWORD BUT NOT CHANGE THE MEAT AND POTATOS OF THE MESSAGE THAT WIDESPREAD CLOUDY SKIES WITH LIGHT RAIN EXPECTED ACROSS CWA TODAY BUT LATE THIS AFTERNOON HEAVIER ACTIVITY POSSIBLE ESPECIALLY EXTREME S. IN THE CWF PACKAGE, WILL MASSAGE WORDING AGAIN FOR PRECIPITATION. PRESSURE GRADIENT REMAINS TOGHT AND SMALL CRAFT ADVISORIES TO CONTINUE. .MIA...SMALL CRAFT ADVISORY ALL WATERS EXCEPT LAKE OKEECHOBEE. $$ fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 955 AM CDT SUN APR 29 2001 MOSTLY SUNNY CONDITIONS THIS MORNING WITH LIGHT WINDS AND TEMPERATURES ABOUT THE SAME AS YESTERDAYS. SOME LOW AND MID LEVEL CLOUDS TO THE SOUTH ALONG PERIPHERY OF GULF SYSTEM...AND ALSO ACROSS EASTERN ARKANSAS AND NORTH MISSISSIPPI WITH AREA OF HIGHER MOISTURE JUST SOUTH OF WEAK FRONTAL BOUNDARY. COOLER...DRIER AIR LIES MUCH FARTHER NORTHEAST IN SOUTHEAST MISSOURI AND WEST TENNESSEE. BACK DOOR FRONT ACROSS TENNESSEE VALLEY SATURDAY SHOWED LITTLE MOVEMENT BUT THUNDERSTORMS LEFT AN OUTFLOW BOUNDARY ALONG THE MS/LA LINE. RUC PROGGED SOUNDINGS FOR THIS AFTERNOON FOR EL DORADO AND MONROE SHOW PRECIPITABLE WATER VALUES FROM .8 TO .9 INCHES...LIFTED INDEX VALUES OF -1 TO -3...TOTAL TOTALS NEAR 50 AND CAPE VALUES OF AROUND 500 J/KG. RELATIVE HUMIDITY VALUES AT 800 MB ALSO INCREASE DRAMATICALLY TO ABOUT 65 PERCENT DURING THE AFTERNOON FOR THIS AREA WITH 700 TO 500 MB LAPSE RATES BETWEEN 6.5 AND 7.0C. WITH THIS IN MIND WILL PUT IN A SLIGHT CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS FOR NORTHEAST PART OF FORECAST AREA. SURFACE WINDS SHOULD BE EAST TO SOUTHEAST OVER FORECAST AREA TODAY...OTHERWISE...NO OTHER CHANGES TO FORECAST. .SHV...NONE. 09 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1025 PM EDT SUN APR 29 2001 00Z RAOBS/WV LOOP AND RUC ANAL SHOW UPR RDG DOMINATING GRT LKS E OF TROF IN SW CAN. 1030MB SFC HI OVR ERN LKS. STRG PRES GRADIENT/SWLY FLOW OVR CWA BTWN HI CENTER AND COLD FNT NOW IN ERN DAKOTAS ON SRN FLANK OF SHRTWV LIFTING NEWD THRU SCNTRL CAN E OF SW CAN TROF. H5 FLOW NRLY PARALLEL TO THIS BNDRY LIMITING FWD SPEED DESPITE MODEST PRES RISES/NWLY SFC FLOW BEHIND BNDRY. WV LOOP/COOLING CLD TOPS OVR NB/SD SUG ANOTHER SHRTWV LIFTING NEWD FM WCNTRL PLAINS. MQT 88D VWP SHOWS SSW 30-40KT WNDS 1K FT AGL. BUT WITH LOSS OF SFC HTG/MIXING... WND SPEEDS OVR CWA GENERALLY DIMINISHING EVEN THOUGH LATEST RUC MODEL SHOWS H85 50KT JET MOVG TOWARD WRN CWA. TSRA/MID CLD AHD OF FNT AS FAR E AS NW MN/NR DLH AT 01Z. CU THAT DVLPD DURG AFTN OVR WRN CWA DSPTD WITH SETTING OF SUN...SKIES NOW MCLR. 00Z GRB SDNG SHOWS RELATIVELY DRY SDNG WITH WELL MIXED LYR UP TO H6...BUT SFC BASED COOLING ALREADY STABILIZING LLVLS. TEMPS MOST PLACES ACRS CWA WELL ABV NORMAL...STILL AS HIGH AS 70-75 AT IWD/CMX. BUT READINGS AS LOW AS MID 40S OVR ERN ZNS WITH SSWLY FLOW OFF CHILLY LK MI. SFC DWPTS GENERALLY IN 30S TO LO 40S...BUT AS HI AS 48 AT CMX. 00Z RUC MODEL SHOWS SFC HI MOVG ONLY VERY SLOWLY E OVRNGT...WITH CWA REMAINING IN STRG SWLY GRADIENT FLOW THRU DAWN WITH CONTD SWLY FLOW ALF...50KT H85 WNDS FCST TO OVRSPRD WRN HALF OF CWA OVRNGT. APPEARS SHRTWV LIFTING NEWD FM WCNTRL PLAINS WL RUN UP COLD FNT OVRNGT. SWLY FLOW ALF WITH SHRTWV RUNNING PARALLEL TO BNDRY WILL CONT TO SLOW EWD PROGRESSION OF FNT. RUC FCSTS THIS BNDRY TO REACH CNTRL MN TOWARD 12Z WITH HIER H7 MSTR/AC JUST EDGING TOWARD IWD ARND 12Z. SO SKIES SHUD REMAIN MCLR EVERYWHERE. ALTHOUGH STRG WNDS WL MOVE IN AT H85 OVR W...XPCT ABSENCE OF INSOLATION WL RESTRICT MIXING AND ANY STRG GUSTS AT THE SFC...JUST MAINTAINING A STEADY SSWLY WND THAT SHOULD NOT ALLOW DECOUPLING. LATEST LAMP GUIDANCE INDICATES MIN TEMP AT IWD WL REMAIN NR 65...NOT OUT OF QUESTION GIVEN DOWNSLOPING SLY WND COMPONENT. GOING FCST HERE OF 60 TO 65 LOOKS OKAY. ALTHOUGH INCRS IN WND ABV BLYR WL NOT BE AS SHARP OVR ERN ZNS... MIXING WL NOT ALLOW TEMP TO FALL ANYWHERE NR DWPT. ALTHOUGH TEMPS SHUD NOT FALL TOO FAR FM PRESENT VALUES EVEN OVR THE E...HAVE GENERALLY LOWERED TEMPS A FEW DEGREES TO TAKE INTO ACCOUNT READINGS ALREADY AOB FCST MINS IN SVRL PLACES. AFDMQT FM DAYSHIFT FOR LATER PDS: MDLS IN REASONABLE AGREEMENT THROUGH 24 HRS...THEN ETA AND AVN DIVERGE SIGNIFICANTLY BY TUESDAY WITH AVN MUCH STRONGER WITH SHRTWV INTO NRN PLAINS AND SRN CANADA AND ASSOCIATED SFC LO AT 48-60 HRS. MONDAY INTO MONDAY NIGHT....CONVERGENCE ALONG AND AHEAD OF TROF MOVING TOWARD UPR MI WILL PROVIDE MAIN FOCUS FOR SHRA/TSRA. ONLY WEAK TO MODEST SYNOPTIC SCALE SUPPORT WITH 700-300 QVECTOR CONVERGENCE AND UPR LVL DIV WITH RIGHT ENTRANCE OF JET INTO WRN ONTARIO. INSOLATION AND MOISTURE ADVECTION WITH T/TD 76/51 SHOULD PROVIDE ENOUGH INSTABILITY WITH CAPES TO AROUND 500 J/KG (OVER SW) FOR SCT CONVECTION. ETA TD NEAR 55-60F AGAIN LOOK TOO HIGH...POSSIBLY FROM EXAGGERATED EVAPOTRANSPIRATION. INSTABILITY SHOULD NOT BE SUFFICIENT TO DELIVER SVR LVL GUSTS OR HAIL DESPITE STRONG UNIDIRECTIONAL ENVIRONMENTAL WIND FIELD (850-700 WINDS TO NEAR 50 KTS). WILL GO CLOSER TO WARMER AVN GUIDANCE FOR TEMPS WITH GOOD MIXING AND MIDDAY INSOLATION. ETA/AVN QPF TIMING LOOKS REASONABLE WITH BEST CHANCE INTO WEST AFT 16Z AND TO CNTRL AROUND 21Z. ENOUGH UNCERTAINTY THOUGH TO KEEP CHANCE MENTIONED FOR ERN CWA. EXPECT SHOWERS TO LINGER MONDAY NIGHT (MAINLY BTWN 00Z-03Z) AS TROF/FRONT MOVES INTO ERN UPR MI. TUESDAY...WILL GO WITH ETA/AVN COMPROMISE ON FEATURES AFFECTING UPR MI ALTHOUGH UKMET/CANADIAN MORE SUPPORTIVE OF AVN. STRONGER AVN SHRTWV TO THE NW WOULD PLACE UPR MI IN UNFAVORABLE RIGHT EXIT REGION (RATHER THAN LEFT EXIT WITH ETA) OF THE JET WITH DRY CONDITIONS. FLATTER ETA SOLN ALONG WITH MORE ABUNDANT LLVL MOISTURE (AGAIN OVERDONE) WOULD BRING PERIOD OF SHRA/TSRA ACRS MOST OF UPR MI AS WEAK SFC LO DEVELOPS OVER MN AND MOVES TOWARD THE AREA. SO...WL MENTION JUST CHANCE POPS. WL GO WITH SLIGHTLY HIGHER POPS TUESDAY NIGHT AS FRONT MOVES THROUGH UPR MI. EXTENDED...ECMWF/MRF/UKMET AND 12Z AVN ARE IN REASONABLE AGREEMENT LEAVING LINGERING FRONTAL BNDRY CLOSE ENOUGH TO UPR MI FOR PCPN CHANCES INTO EARLY FRIDAY AS WEAK SHRTWVS MOVE TOWARD THE AREA WITH SW FLOW. WL GO BLO GUIDANCE FOR TEMPS BY FRIDAY(ESPECIALLY NORTH) WITH NRLY FLOW DEVELOPING AS FRONT SINKS TO THE SOUTH. BUILDING BLOCKING RDG TO THE WEST WITH SFC HI PRES SINKING INTO THE GRT LAKES SHOULD BRING A COUPLE OF SUNNY DRY DAYS FOR THE WEEKEND. .MQT...NONE. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 PM EDT SUN APR 29 2001 MAIN FCST CONCERNS THIS PACKAGE INCLUDE SHRA/TSRA TIMING/POPS. WV IMAGERY AND RUC ANALYSIS INDICATED BROAD MID/UPR LVL RDG OVER THE SE CONUS INTO THE WRN GRT LAKES. STRONG 150 KT H3 JET WAS MOVING TOWARD PAC NW WILL HELP NUDGE RDG EASTWARD WITH CONTINUED BROADENING OF WRN TROF INTO THE NRN PLAINS. STUBBORN MCS OVER ERN UPR MI...FUELED BY H8 LLJ THETA-E ADVECTION WAS DIMINISHING QUICKLY AS SYSTEM AS MOISTURE INFLOW WEAKENS. OTHERWISE...AREA HAD CLEARED OUT WITH SCT DIURNAL CU OVER WRN UPR MI WHERE SFC TD HAD CLIMBED INTO THE MID 40S F. MDLS IN REASONABLE AGREEMENT THROUGH 24 HRS...THEN ETA AND AVN DIVERGE SIGNIFICANTLY BY TUESDAY WITH AVN MUCH STRONGER WITH SHRTWV INTO NRN PLAINS AND SRN CANADA AND ASSOCIATED SFC LO AT 48-60 HRS. TONIGHT...GRADIENT REMAINS STRONG ENOUGH TO SUSTAIN BREEZY CONDITIONS AFTER DIURNAL COOING/STABILIZATION AS 925 WINDS FCST AT 45-50 KTS AND BNDRY LYR WINDS TO 25-30 KTS. MIXING SHOULD KEEP TEMPS AOA ALREADY VERY MILD GUIDANCE TEMPS IN THE MID 50S...PARTICULARLY FOR AREAS WITH DOWNSLOPE SSW FLOW. MONDAY INTO MONDAY NIGHT....CONVERGENCE ALONG AND AHEAD OF TROF MOVING TOWARD UPR MI WILL PROVIDE MAIN FOCUS FOR SHRA/TSRA. ONLY WEAK TO MODEST SYNOPTIC SCALE SUPPORT WITH 700-300 QVECTOR CONVERGENCE AND UPR LVL DIV WITH RIGHT ENTRANCE OF JET INTO WRN ONTARIO. INSOLATION AND MOISTURE ADVECTION WITH T/TD 76/51 SHOULD PROVIDE ENOUGH INSTABILITY WITH CAPES TO AROUND 500 J/KG (OVER SW) FOR SCT CONVECTION. ETA TD NEAR 55-60F AGAIN LOOK TOO HIGH...POSSIBLY FROM EXAGGERATED EVAPOTRANSPIRATION. INSTABILITY SHOULD NOT BE SUFFICIENT TO DELIVER SVR LVL GUSTS OR HAIL DESPITE STRONG UNIDIRECTIONAL ENVIRONMENTAL WIND FIELD (850-700 WINDS TO NEAR 50 KTS). WILL GO CLOSER TO WARMER AVN GUIDANCE FOR TEMPS WITH GOOD MIXING AND MIDDAY INSOLATION. ETA/AVN QPF TIMING LOOKS REASONABLE WITH BEST CHANCE INTO WEST AFT 16Z AND TO CNTRL AROUND 21Z. ENOUGH UNCERTAINTY THOUGH TO KEEP CHANCE MENTIONED FOR ERN CWA. EXPECT SHOWERS TO LINGER MONDAY NIGHT (MAINLY BTWN 00Z-03Z) AS TROF/FRONT MOVES INTO ERN UPR MI. TUESDAY...WILL GO WITH ETA/AVN COMPROMISE ON FEATURES AFFECTING UPR MI ALTHOUGH UKMET/CANADIAN MORE SUPPORTIVE OF AVN. STRONGER AVN SHRTWV TO THE NW WOULD PLACE UPR MI IN UNFAVORABLE RIGHT EXIT REGION (RATHER THAN LEFT EXIT WITH ETA) OF THE JET WITH DRY CONDITIONS. FLATTER ETA SOLN ALONG WITH MORE ABUNDANT LLVL MOISTURE (AGAIN OVERDONE) WOULD BRING PERIOD OF SHRA/TSRA ACRS MOST OF UPR MI AS WEAK SFC LO DEVELOPS OVER MN AND MOVES TOWARD THE AREA. SO...WL MENTION JUST CHANCE POPS. WL GO WITH SLIGHTLY HIGHER POPS TUESDAY NIGHT AS FRONT MOVES THROUGH UPR MI. EXTENDED...ECMWF/MRF/UKMET AND 12Z AVN ARE IN REASONABLE AGREEMENT LEAVING LINGERING FRONTAL BNDRY CLOSE ENOUGH TO UPR MI FOR PCPN CHANCES INTO EARLY FRIDAY AS WEAK SHRTWVS MOVE TOWARD THE AREA WITH SW FLOW. WL GO BLO GUIDANCE FOR TEMPS BY FRIDAY(ESPECIALLY NORTH) WITH NRLY FLOW DEVELOPING AS FRONT SINKS TO THE SOUTH. BUILDING BLOCKING RDG TO THE WEST WITH SFC HI PRES SINKING INTO THE GRT LAKES SHOULD BRING A COUPLE OF SUNNY DRY DAYS FOR THE WEEKEND. .MQT...NONE. JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1100 AM EDT SUN APR 29 2001 THE LATEST APX AND MQT 88D DATA SHOWS MID AND UPPER LEVEL MOISTURE MOVING OVER EAST UPPER MICHIGAN AND THE WESTERN STRAITS REGION. THE MQT 88D AND LIGHTNING DATA SHOWS A FEW SHOWERS AND THUNDERSTORMS MOVING OVER CENTRAL UPPER MICHIGAN. VISIBLE SATELLITE LOOP SHOWS CLOUDY SKIES OVER EAST UPPER MICHIGAN...BROKEN MID LEVEL CLOUDS OVER THE STRAITS AND SCATTERED MID LEVEL CLOUDS ACROSS THE REST OF LOWER MICHIGAN. THE MAIN FORECAST CONCERN THIS AFTERNOON WILL BE CENTERED AROUND PRECIPITATION CHANCES AND CLOUD TRENDS OVER THE FORECAST AREA. THE SHOWERS AND THUNDERSTORMS OVER CENTRAL UPPER HAVE FORMED IN A WEAK THTE RIDGE WITH 850 MB DEW POINTS AROUND 4C. THIS AREA IS ALSO BEING INFLUENCED BY WEAK ISENTROPIC LIFT NOTED ON THE 300K SURFACE. THE LATEST RUC SHOWS A LARGE AREA OF HIGH PRESSURE TO BE LOCATED OVER THE EASTERN LAKES TODAY WITH UPPER LEVEL RIDGING BUILDING OVER THE STATE THIS AFTERNOON. MODEL SOUNDINGS SHOW EXTREMELY DRY CONDITIONS FROM THE SURFACE THROUGH 8500 FEET INTO THIS EVENING... WITH MID LEVELS REMAINING MOIST INTO THIS EVENING. THE LATEST RUC SHOWS SURFACE DEW POINTS AND 850 MB DEW POINTS TO REMAIN DRY OVER MUCH OF THE FORECAST AREA INTO THIS EVENING... GENERALLY IN THE UPPER 20S TO LOW 30S AT THE SURFACE AND UNDER 0C AT 850 MB. HOWEVER...850 MB DEW POINTS ARE PROGGED TO INCREASE TO AROUND 2C OVER EAST UPPER BY 00Z. THE LATEST APX 88D SHOWS SCATTERED 20 TO 30 DBZ RETURNS MOVING OVER EAST UPPER AND EXTREME NORTHERN LOWER MICHIGAN. WITH THE DRY LAYERS IN PLACE THIS AFTERNOON FROM THE SURFACE THROUGH 8500 FEET... WOULD EXPECT ONLY LIGHT PRECIPITATION THIS AFTERNOON. WILL MENTION SPRINKLES OVER EAST UPPER BUT WILL ALSO ADD MENTION TO THE WESTERN STRAITS WHERE 850 MB WILL BE SLOWLY INCREASING TODAY. WILL KEEP THE REST OF THE FORECAST AREA DRY THIS AFTERNOON. DUE TO THE LATEST SATELLITE TRENDS WILL GO MOSTLY CLOUD EAST UPPER ...PARTLY SUNNY ACROSS EXTREME NORTHERN LOWER AND MOSTLY SUNNY ACROSS THE REST OF THE FORECAST AREA. APX...NONE. SWR mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 725 PM EDT SUN APR 29 2001 WILL UPDATE FORECAST. CONSIDERABLE STRATO-CU ACROSS CENTRAL AND SOUTHERN PORTION OF CWA. RUC/META SUGGEST THIS CLOUDINESS WILL CONTINUE ACROSS THE AREA THRU EARLY MORNING HOURS. SHOWERS DEVELOPED ALONG OLD FRONTAL BOUNDARY...JUST SOUTH OF CSRA. EXPECT THESE SHOWERS TO REMAIN SOUTH OF REGION BASED ON MSAS...MOISTURE FLUX/INSTABILITY JUST SOUTH OF AGS. DRIER AIR TRYING TO SPREAD SOUTH FROM NORTH CAROLINA...SHOULD BE SLIGHTLY COOLER NORTHERN ZONES WITH FEWER CLOUDS EXPECTED...SO WILL RAISE OVERNIGHT LOWS IN THE CSRA SLIGHTLY. FCSTID = 19 CAE 51 79 50 80 / 0 0 5 0 AGS 53 81 47 80 / 0 0 0 0 SSC 51 79 50 80 / 0 0 0 0 OGB 53 81 47 80 / 0 0 0 0 .CAE... GA...NONE. SC...NONE. AWP sc AREA FORECAST DISCUSSION...CORRECTED FOR POP NUMBERS NATIONAL WEATHER SERVICE NASHVILLE TN 300 PM CDT SUN APR 29 2001 FORECAST QUANDARIES...PCPN...CLOUD COVER...TEMPS. CURRENT ASOS/AWOS OBSERVATIONS AND REGIONAL SATELLITE IMAGERY SHOWING SCT CI ENTERING SE SECTIONS OF THE MID STATE...WITH "BANDS" OF CI TO OUR S. REGIONAL MOSIAC RADAR IMAGERY DEPICTING SCT SH/TS ACTIVITY ACROSS S CNTRL AL. AT THIS TIME...WITH INSTABILITY INDICES INDICATING STABLE CONDITIONS. SFC MSAS/HAND ANALYSES SHOWING THAT WEAK FRONTAL BOUNDARY HAS MOVED TO OUR S...WITH AN INVERTED SFC TROUGH DEVELOPING OVER THE E TN RIVER VALLEY AS HIGH PRESSURE OVER THE CNTRL ATLANTIC COAST AMPLIFIES. ALSO OF INTEREST...TEMPS AROUND 80...DEWPOINTS RANGING FROM 40S N TO 50S S...AND NE WINDS AROUND 10KTS. RUC UPPER AIR ANALYSES SHOWING A CONTINUANCE IN BROAD UPPER LEVEL RIDGING INFLUENCES. 12Z SUN REGIONAL MODEL EVOLUTIONS THROUGH 12Z TUE ARE QUIET SIMILAR. HOWEVER...THREE MINOR DISCREPANCIES OF NOTE. FIRST...NGM HAS A "BROADER" SFC SOLUTION IN REFERENCE TO EFFECTS OF ATLANTIC HIGH PRESSURE DEVELOPMENT. SECOND...ETA DEVELOPS AN UPPER LOW INLAND AT 36 TO 48HRS WILL THE AVN DOES NOT. AS POINTED OUT BY THE LATEST MODEL DIAGNOSTIC DISCUSSION...ETA SEEMS TO BE OVERDONE. THIS DISCUSSION ALSO POINTS OUT THE THIRD DISCREPANCIES THAT THE AVN DEVELOPS AN UPPER LEVEL TROUGH OVER OUR REGION. AM INCLINED TO AGREE WITH THEM THAT THE ETA SOLUTION IS PREFERRED HERE. MODELS ALSO WELL INITIALIZED...BUT PREFER THE AVN SOLUTION AS IT PERTAINS TO WEAK FRONT POSITION AND RIDGING PATTERN ALOFT. THUS ...WILL LEAN TOWARD THE AVN SOLUTION AND DISREGARD UPPER LEVEL TROUGH DEVELOPMENT LATER IN THE PERIOD. RIDGING SFC AND ALOFT WILL CONTINUE TO BE THE DOMINATE "WEATHER MAKER" THROUGH THE PERIOD...WITH S-SWLY FLOW DEVELOPING AS SFC CNTRL ATLANTIC HIGH PRESSURE SYSTEM MOVING FURTHER E. FIRST FORECAST QUANDARY CENTERS AROUND ANY PCPN DEVELOPMENT. WEAK BOUNDARY TO OUR SOUTH RESULTING IN SCT CONVECTION ACROSS S AL PRESENTLY. RUC MODEL STILL SHOWING STABILITY OVER MOST OF CWA ...BUT WILL HAVE TO MONITOR SITUATION UP TO PRESS TIME TO SEE IF ANY PCPN DEVELOPS...ESPECIALLY ACROSS THE CUMBERLAND PLATEAU WHERE MOISTURE ADVECTION POTENTIAL IS GREATEST AND SLIGHT INSTABILITY IS STILL POSSIBLE. FOR REMAINDER OF PERIOD. WITH DOMINATE RIDGING INFLUENCES ALOFT ...BELIEVE ANY CONVECTION THAT MIGHT RESULT WILL BE ONLY OF DIURNAL NATURE...AND HAVE NO REASON TO SUSPECT DEVELOPMENT ANY FURTHER THAN THE EARLY EVENING HOURS TONIGHT AND MONDAY NIGHT. THUS...WILL KEEP NIGHTS "DRY". AREA PLACED IN GENERAL TS CRITERIA IN DAY TWO CONVECTIVE OUTLOOK WITH MOS POPS ADDRESSED IN THE WIDELY SCATTERED CATEGORY BY 00Z TUE. QPF VALUES SHOWING LITTLE IN THE WAY OF MEASURABLE RAINFALL WITH NO MAJOR TRIGGERING MECHANISM OF NOTE AS WEAK FRONT EXPECTED TO WASH OUT BY TONIGHT. BEST INSTABILITY ACROSS W CWA DURING THE AFTERNOON HOURS ON MON. WILL ADDRESS THIS QUANDARY WITH ISOLATED SH/TS POPS. SECOND FORECAST QUANDARY CENTERS AROUND CLOUD COVER. ATLANTIC MOISTURE EXPECTED TO MOVE INTO THE REGION...ESPECIALLY SE SECTIONS...AFTER 06Z MON...WITH LOW LEVEL MOISTURE PREVALENT THROUGH THE REMAINDER OF THE PERIOD...BUT WITH LITTLE ALOFT. DO UNDERSTAND THE CONCERN IN THE MRXAFD THAT THE MODELS MIGHT BE TOO AGGRESSIVE WITH THIS MOISTURE ADVECTION...BUT BELIEVE ENOUGH MOISTURE WILL BE AVAILABLE WITH SLY WIND FLOW TO SUPPORT THE INTRODUCTION OF VARIABLE CLOUDINESS BOTH MON AND TUE AFTERNOONS. WILL ADDRESS SKY CONDITIONS AS PARTLY CLOUDY DURING THE NIGHT TIME HOURS FOR BOTH DAYS. EXTENDED...RIDGING PATTERN SFC AND ALOFT WILL CONTINUE... ALTHOUGH NOT AS WELL DEVELOPED AS PRESENTLY...THROUGH 00Z SAT ...UNTIL A S CANADIAN HIGH PRESSURE BUILDING AND PRONOUNCED UPPER LEVEL RIDGE BUILDS INTO THE AREA BY 00Z SUN. WILL CONTINUE TO ADDRESS SKY CONDITIONS AS PARTLY CLOUDY THROUGH THE EXTENDED. TEMPS...DESPITE BNA REACHING FORECASTED LOW THIS MORNING...SEVERAL LOCATIONS IN OUTLYING AREAS WERE A FEW DEGREES COOLER. BELIEVE THIS WILL BE THE SAME CASE TONIGHT. WILL GO CLOSE TO MOS VALUES FOR LOWS AND HAVE NO REASON TO DEVIATE FROM A COMPROMISE SOLUTION BETWEEN MOS AND FAN VALUES FOR LOWS AND HIGHS DURING THE PERIOD. SOME LOWS FROM COOP STATIONS LAST NIGHT: BNA 52...WOODBURY 40...SMYRNA...39...AND COALMONT 40...AND FALL CREAK FALLS 40. BECAUSE OF THIS...WILL ADDRESS LOWS TEMPS WITH OUTLYING AREA REMARKS IN THE W AND PLATEAU REMARKS IN THE E. PRELIMINARY NUMBERS FOR COORDINATION PURPOSES ONLY... BNA 058/082/058/081 1211 CSV 052/075/054/076 1111 .BNA...NONE. 14 JBW tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 1004 AM CDT SUN APR 29 2001 CURRENT ASOS/AWOS OBSERVATIONS AND REGIONAL SATELLITE IMAGERY SHOWING A FEW CI ACROSS THE MID STATE...WITH A FEW AC/CI DEVELOPING OVER N AL. SFC MSAS/SFC DEPICTIONS SHOWING WEAK STATIONARY FRONT OVER N AL AND GA...EXTENDING INTO SW CWA/S PORTIONS...WITH TIGHT DEWPOINT GRADIENT OVER REGION. TEMPS 60 TO 65...DEWPOINT DEPRESSIONS 10 TO 15 DEGREES...NE WINDS 5 TO 10 MPH...UNDER STABLE ATMOSPHERIC CONDITIONS. 12Z KOHX SOUNDING PROFILE SHOWING LITTLE MOISTURE AVAILABILITY WITH PRECIP WATER VALUES ONLY AROUND 0.60 INCH. 12Z UPPER AIR CHART ANALYSES SHOWING WELL DEVELOPED RIDGING OVER THE MID STATE WITH 700MB AND 500MB RIDGE AXES CENTERED IN THE CWA. AS A RESULT... VERY LIGHT WIND FLOW ALOFT. RUC "WASHING OUT" FRONT AS THE DAY PROGRESSES WITH DRIER DEWPOINTS ADVECTING INTO THE REGION. RUC SHOWING SOME MOISTURE CONVERGENCE ACROSS E PORTIONS OF AREA THROUGH THE AFTERNOON HOURS...WITH SLIGHT INSTABILITY OF NOTE IN RUC SOUNDING PROFILES. MIGHT SEE SOME ISOLATED SH/TS DEVELOPMENT ACROSS THE E THIS AFTERNOON AIDED BY OROGRAPHIC LIFTING AND DEVELOPMENT OF A WEAK INVERTED SFC TROUGH. HOWEVER...WITH UPPER LEVEL RIDGING INFLUENCES BEING SO PRONOUNCED... POSSIBLE CONVECTION WILL BE ISOLATED ENOUGH THAT IT DOES NOT NEED TO BE MENTIONED IN ZONES PRESENTLY. WILL MONITOR RADAR AND SATELLITE TRENDS. CURRENT TEMP TRENDS IN LINE WITH FORECASTED HIGHS AND MOS/LAMP GUIDANCE VALUES. TO SUM UP...WILL NOT UPDATE FORECAST AT THIS TIME. .BNA...NONE. 14 JBW tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 330 AM CDT/EST MON APR 30 2001 JUST A FEW CHANGES TO GOING FCST THIS MORNING. JUST A TRIVIALITY BUT WILL GO MOSTLY SUNNY FOR CHARACTER OF THE DAY OVER NERN IL AND NWRN IN. DON/T EXPECT MORE THAN A FEW CU AND HIGHER BASES DEBRIS FROM CONVECTION TO W MAY MAKE IT IN HERE LATE IN THE DAY BUT THERE SHOULD BE A LOT MORE SUN THAN CLOUDS. IN N CNTRL IL THERE IS A GREATER LIKELIHOOD OF A LITTLE MORE CONVECTIVE DEBRIS EARLIER IN THE DAY SO WILL KEEP PARTLY SUNNY GOING THERE. WILL KEEP CHC PROB IN FOR TSTMS TNGT AS GUIDANCE IS CONSISTENT WITH SHORT WAVE LIFTING OUT OF CNTRL PLAINS TDY. ETA/NGM/RUC HAVE A GOOD FIX ON THIS FEATURE AND ITS ASSD MOISTURE FIELD. THESE MDLS SHOW SIG DAMPENING OUT OF S/W BY 00Z AS FEATURE LIFTS NEWD ACROSS UPR GRTLKS. REMAINING DYNAMICS WILL LIKELY BE LIMITED TO THAT AREA AS WELL. WILL KEEP CHC POPS IN DUE TO FCST INSTABILITY. ETA FCST SOUNDINGS YIELD CAPES AROUND 1500 J/KG AND LI/S OF ARND -5...TOTALS OF 54. AT 00Z THIS EVE SOUNDING IS FCST TO BE NRLY ADIABATIC THROUGH 850 MB. OTHER CHG TO GOING FCST WILL BE TO INTRO AT LEAST LO CHC POPS FOR LATE TUES/TUES NGT. LAST GUIDANCE RUN SHOWS GOOD MDL CONSISTENCY /ALTHOUGH AVN A LTL SLOER THAN ETA/ IN BRINGING IN MAINTAINING RATHER UNSTABLE AMS ACROSS RGN WITH A RATHER STG LO LVL FLOW OF AROUND 40 KTS FROM THE SSW. ISENTROPIC FCSTS ALSO SHOW A BETTER POTENTIAL FOR MORE SIG VERTICAL VELOCITY FIELDS AT THIS TIME AS WELL AND MDL CONVECTIVE INDICES ALSO POINT TO TSTM POTENTIAL TUES AFTN-EVE. GOING TEMP FCST LOOKS PRETTY GOOD...ONLY MINOR CHGS. .CHI...NONE $$ MERZLOCK il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 AM EDT MON APR 30 2001 THE MAIN CONCERN THIS FRCST PERIOD IS THE ONSET OF THE SHRA/TSRA AND TEMPERATURES TDA. WV IMAGERY/RUC ARE SHOWING AN ULVL RIDGE OVER ERN ONTARIO AND LAKE HURON. WV IMAGERY DEPICTS A SHRTWV OVR WRN U P. A COLD FRONT STRETCHES FM CNTRL HUDSON BAY ACRS WRN ONTARIO AND CNTRL MN. EVENING SOUNDING DATA SHOWING A LLJ ACRS CENTRAL PLAINS...WAS RESPONSIBLE FOR THE DRAWING OF GULF MOISTURE INTO THE WRN GRT LAKES REGION THIS MORNING. MDLS IN GOOD AGREEMENT OUT TO 36 HRS IN TREKKING THE RIDGE ACRS THE ERN GT LAKES. VARIATION SHOWING IN THE TRACKING OF THE NEXT SYS. AVN CHG LTL IN PROGGING AN ULVL CLOSED LOW INTO SRN MANITOBA BY 00Z WED. THIS ETA/NGM SOLN TRENDING TWRD THE AVN SOLN AND SUPPPORT THE DVLPMNT OF THE A LOW OVR SRN MANITOBA BY 00Z WED. SINCE AVN HAD THE BEST RUN TO RUN CONSISTENCY AND ETA/AVN SEEMS TO BE TRENDED TO SLOWER DRY SOLN OF AVN...WILL GO WITH AVN...HOWEVER...CONFIDENCE IS LOW. THE SHRTWV WILL MOV INTO WRN UP BY 00Z TUE IN ASSOC WITH THE CDFNT. THE CDFNT WAS PRODUCING SHRA AND TSRA AS IT MOVED THRU NRN PLAINS THIS AM. THE TSRA WERE HEAVIEST IN AREAS OF BEST ISENTROPIC LIFT AND MEAN 1000-500MB RH OF >70PCT. THIS AREA ALSO WAS UNDER THE R ENTRANCE REGION OF THE ULJ. THE ULJ...THE SHRTWV...AND THE MSTR WILL SERVE TO FOCUS THE ENERGY ALONG THE CDFNT AS IT MOVES THRU WRN UPPER MICHIGAN TDA. A SFC BASED INVERSION WILL KEEP THE WNDS FM MIXING DN THIS AM. HOWEVER...DAYTIME SUN WILL ALLOW THE HEATING OF THE LOW LVLS AND THE ELIMINATION OF THE SFC BASED INVERSION. THIS WILL THEN ALLOW SOME OF THE 925MB WNDS TO MIX TO SFC. MDLS KEEP MSTR MAINLY IN THE W...SO XPCT NUM TSRA OVR WRN UP. CAPE VALUES XPCT TO BE 1000-1500J/KG...LI WILL FALL TO -3...AND K INDEX WILL REACH 30. FA UNDER SLIGHT RISK OF SVR TDA. ALL SUG TSRA DVLPMENT. XPCT RAPID HEATING THIS AM...BEFORE CLDS ENTER THIS AFTN. TRAJ FCST SHOWING AIR MASS OVR WI WILL TREK TWRDS U P. HI OVR WI YTD WERE AROUND 80. XPCT A LTL MORE CLD CVR LATE IN THE DAY...SO WILL WILL GO WITH UPR 70S ACRS MOST OF FA. THE ISENTROPIC ENERGY...SHRTWV...AND MSTR WILL CONT TO FOCUS THE PCPN AND ISENTROPIC ENERGY ALONG THE FRONT TNGT. THE QPF IN THE MDLS SUPPORT THE DEPOSIT OF A QUARTER TO THREE QUARTER OF AN INCH OF SHRA OVR VARIOUS SECTIONS OF THE FA. ETA FCST SOUNDING ETA SHOWING THE SFC-H5 MOIST LAYER WILL BCM NRLY SATURATED OVR THE UP BY LATE AFTN. AVN/GEM A LTL DRYER. AVN/GEM SHOWING QUITE DRY IN THE LOW LEVELS ON TUES...ESPECIALLY IN THE W. HOWEVER...THERE IS STILL PLENTY OF INSTABILITY. AVN HAS WEAK SHRTWV WILL TRAVERSE THE REGION ON TUE. ETA/NGM ARE QUITE A BIT MORE MOIST IN THE LOW LEVELS. THERE IS ENOUGH INSTABILITY EVEN IN AVN...NOT TO RULE OUT A POSSIBILITY OF A SHRA OR TWO. SINCE A SHRA ARE ALREADY MENTIONED WILL NOT TAKE THEM OUT ATTM. ALL MDLS AGREE THAT MSTR WILL RETURN TO UPR GRT LAKES REGION TUES NGT AS ANOTHER COLD FRONT AND VORT MAX TRAVERSE THE REGION. EXPECT SHRA/TSRA TUE NGT AND WED ALSO. .MQT...NONE. DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA NE 305 AM CDT MON APR 30 2001 CONVECTION IS THE MAIN PROBLEM IN THE SHORT TERM...THEN AGAIN BY LATE TUESDAY. SURFACE ANALYSIS EARLY THIS MORNING SHOWED CDFNT FROM NCNTRL MN INTO NCNTRL NE. TROF HAD PUSHED OUT AHEAD OF THE FNT INTO NERN AND SCNTRL NE WITH AREA OF SHOWERS/THUNDERSTORMS. OVERALL TREND OF THAT ACTIVITY HAS BEEN FOR A GRADUAL DECREASE THE PAST 3 HOURS ACCORDING TO RADAR AND IR STLT IMAGERY LOOPS... WHICH SHOW WARMING CLOUD TOPS. LATEST 40 KM RUC OUTPUT BRINGS SOME PCPN ACROSS THE FORECAST AREA THIS MORNING...AND THE ETA SHOWS SOME POTENTIAL FOR THE AFTN HOURS. CDFNT WILL MAKE SOME PROGRESS TODAY BEFORE STALLING LATE. WITH MORE CLOUDS...THREAT OF PCPN AND COOLER 850 MB TEMPERATURES...HIGHS THIS AFTN SHOULD BE 3 TO 7 DEGREES F COOLER THAN YESTERDAY. HAVE USED A BLEND OF THE MODELS...GIVING THE ETA A BIT MORE WEIGHT SINCE IT SEEMS TO BE HANDLING THE PCPN IN THE LATER PDS THE BEST. PATTERN CHANGE STILL TAKING SHAPE FOR THIS WEEK... WITH A DECENT TROF OR CLOSED CIRCULATION DEVELOPING OVER THE ROCKY MOUNTAIN REGION BY LATE WEDNESDAY. TEMPERATURES WILL BE BOOSTED INTO THE 80S ACROSS THE AREA AGAIN ON TUESDAY...BUT A STRONG CDFNT WILL MOVE THROUGH LATE TUESDAY AND TUESDAY NIGHT. THIS SUGGESTS THAT NGM MOS POPS FOR TUESDAY NIGHT ARE MUCH TOO LOW. HAVE INCREASED THEM INTO THE LIKELY RANGE...AND THE PCPN COULD BE SUBSTANTIAL. WITH SWLY MID LEVEL FLOW AND A STALLED FRONT SOMEWHERE IN THE CENTRAL U.S. A CHANCE OF SHOWERS AND THUNDERSTORMS SEEMS THE WAY TO HANDLE THE PATTERN INTO THE WEEKEND. MIGHT ADJUST HIGH TEMPERATURES A BIT AFTER TAKING A CLOSER LOOK AT LATEST MRF OUTPUT. FIRST DRAFT OF THE WORK ZONES WAS SENT. .OMA...NONE. MILLER ne EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 1010 AM EDT MON APR 30 2001 CURRENT...CWA REMAINS FIRMLY ENTRENCHED WITHIN CRCLN AROUND SOUTH SIDE OF STRONG HIGH PRES CENTERED ALONG THE ATLC SEABOARD. "REX" TYPE BLOCK AT H50 WITH RIDGE OVER TN VALLEY AND TROUGH IN THE NE GOMEX VERY SLOWLY DRIFTING EAST IN TANDEM ATTM. MULTIPLE WEAK MID LEVEL VORT CENTERS (NOTED ON RUC ANYLS) EMBEDDED WITHIN THE GOMEX TROUGH OVER THE NORTHERN GOMEX/GULF COAST WITH AN ELONGATED LOBE OF VORTICITY OVER THE GOMEX BETWEEN 80-90W AND 25-27N. CWA IS BETWEEN THE TWO ATTM. KMLB 88D SHOWS CONVECTIVE SHOWERS MOVING ASHORE NEAR PALM BAY...THEN EXTENDING T ABOUT 30-40NM OFFSHORE OF KMXR. AREA OF STRATIFORM PRECIP IS NOTED OVER THE SOUTHERN 3 COS. 12Z RAOBS SHOW HIGHEST PWATS CONTINUE OVER SOUTH FL (1.4" TO 1.6") WITH DRIER LOW-MID LEVEL AIR STILL HOLDING FAST OVER EAST CENTRAL/NE FL (0.8" TO 0.9"...A FEW TENTHS HIGHER AT KTBW. ANOTHER FORECAST WHERE GENERAL PATTERN IS PRETTY STRAIGHTFORWARD... YET THE MINUTIAE WILL MORE OF A DETERMINANT. ETA/NGM INDICATE TREND TOWARD INCREASING DIFF PVA OVER THE ENTIRE CWA. THE AVN...WHICH USUALLY HANDLES THE H50 VORT FIELDS A BIT BETTER...IS LESS BULLISH ON THIS...ESP OVER THE SOUTHERN CWA. ALL THREE SHORT RANGE MODELS AS WELL AS THE 06Z MESOETA SHOW AN INCREASE IN H25 DIVG THIS AFTERNOON ...AND THIS LINES UP WITH 6HR TIME LAPSE OF WATER VAPOR/RUC ANLYS. BASED ON WATER VAPOR WHICH SHOWS AS DISTINCT N-S LINE WHICH LINES UP WITH LEADING EDGE OF VORT MINIMA...WILL GO WITH THE AVN SOLUTION WHICH WOULD PLACE SOUTHERN COUNTIES IN NVA A GOOD PART OF THE AFTERNOON. FARTHER NORTH...PRECIP CHANCES 20-30 AT BEST LOOKS FINE OVERALL TREND OF THE ZFP IS ON THE MARK AS HIGHEST PRECIP CHANCES WILL BE SOUTH (IN PROXIMITY OF DEEPER MOISTURE) AND NEAR THE COAST AS WEAK CONVERGENCE BANDS CONTINUE TO MOVE ASHORE. QUANTITATIVELY... WE MAY NEED TO TWEAK VALUES DOWN ACROSS THE NORTH BY 10%. IF IT WEREN'T FOR WHAT I PERCEIVE AS A SLIGHTLY LESS CONDUCIVE SYNOPTIC PATTERN TEMPORARILY EVOLVING OVER THE SOUTHERN COUNTIES THIS AFTNN I WOULD CERTAINLY BUMP THEM UP TO 70-80% PER CURRENT RADAR COVERAGE. AS IT STANDS NOW...I THINK 50-60 WILL SUFFICE. MARINE...FORECAST LOOKS FINE. WILL TWEAK SEAS UP TO 8-10 TO COVER OCCASIONAL 9.5FT @41009 AND 10FT @41010. THANKS TBW...APPRECIATE YOUR INSIGHTS. .MLB...SCA FLAGLER BEACH TO JUPITER INLET. PUBLIC/MARINE...CRISTALDI AVIATION/FIRE WX...WIMMER fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 1000 AM CDT MON APR 30 2001 MID AND HIGH LEVEL CLOUDINESS AHEAD OF SURFACE FRONT/TROF ACROSS SOUTHERN HIGH PLAINS ARE APPROACHING THE FORECAST AREA FROM THE WEST THIS MORNING. HOWEVER CLOUDS ARE DISSIPATING AS THEY MOVE INTO SURFACE RIDGE OVER THE EASTERN STATES. SKIES SHOULD BECOME PARTLY CLOUDY OVER NORTHERN SECTIONS BY AFTERNOON. LATEST RUC SHOWS INCREASING LOW LEVEL MOISTURE FROM THE EAST THIS AFTERNOON WITH INCREASING MOISTURE ABOVE 500 MB ACROSS THE NORTHWEST SECTION THIS AFTERNOON. WILL CHANGE WORDING ACROSS THE EAST TO BECOMING PARTLY CLOUDY WITH CU FORMING DURING THE AFTERNOON. AIRMASS IS SLIGHTLY UNSTABLE BUT DRIER THAN SUNDAY SO WILL NOT ADD ANY SHOWERS IN. NO OTHER CHANGES NEEDED FOR UPDATE. .SHV...NONE. 09 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1130 AM EDT MON APR 30 2001 WV LOOP AND 12Z RAOBS SHOW H5 TROUGH OVR NCTNRL CONUS WITH UPR RIDGING FOUND ON BOTH WEST AND EAST COASTS. PRIMARY SHRTWV OF CONCERN FOR TDY ATTM IS PUNCHING INTO SW MN. AT THE SFC...A FRONTAL BOUNDARY LIES FM NRN ONTARIO INTO CNTRL MN...EXTENDING SW INTO ERN KS. BOUNDARY SERVING AS A FOCUS TO POOL SFC DWPTS FM 50-55F WITH DWPTS IN THE 30S ON BOTH SIDES OF BOUNDARY. OVRNIGHT LLJ AIDED SHRA ALONG BOUNDARY ARE DISSIPPATING AS THEY MOVE NE INTO ONTARIO PER KDLH 88D. MAIN CONCERNS TODAY FOCUS ON AMOUNT OF MOISTURE ADVECTION INTO FA AHEAD OF INCOMING BOUNDARY...AND DEVELOPMENT/TIMING OF CONVECTION ALONG BOUNDARY. RAOBS FM INL/MPX/GRB POINT TO SHARP GRADIANT TO H85 DWPT ACROSS AREA WITH 9C FOUND AT INL BUT ONLY 3C AT GRB. 12Z ETA/LATEST RUC DEPICT THAT THIS RIBBON OF 6-8C TD WILL SLIDE TOWARD UPR MI AFT 18Z AS SFC/H85 FRONTAL BOUNDARY ADVANCES EAST ALSO. EXPECT INCOMING SFC/H85 TROUGH AND WEAK H7-H3 Q-VECTOR CONVERGENCE TO PRODUCE SCT -SHRA AFT 21Z...ESPECIALLY IN AREA OF BEST H95-H85 CONVERGENCE ALONG BOUNDARY. HAVE TAKEN ANY POPS OUT OF EAST AS BOUNDARY WON/T ARRIVE UNTIL EVENING HOURS. AS FOR POTENTIAL OF ANY THUNDER...SFC DEWPTS REMAIN IN THE 40S AHEAD OF BOUNDARY AND WITH LACK OF COUPLED DYNAMICS AND LOW-LEVEL FORCING DON/T EXPECT MUCH IN THE WAY OF SIG DWPT ADVECTION IN AREAS THAT SEE PLENTY OF SUNSHINE. IN FACT...MECHANICAL MIXING WILL ONLY LOWER DWPTS INTO LOWER 40S ACROSS FA THRU AFTN. MAXIMUM POTENTIAL FOR ANY THUNDER WILL EXIST OVR FAR SWRN FA WHERE DWPTS COULD CLIMB INTO 50-55F RANGE BEFORE FRONT APPROACHES. USING A SOUNDING WITH INITAIL SFC PARCEL OF 75/55 AT IWD AT 21Z YIELDS AROUND 700 J/KG OF CAPE WITH LI/S AROUND -3C. FARTHER EAST AT IMT...A PROFILE WITH SFC PARCEL OF 78/50 GIVES CAPE VALUES ONLY APPROACHING 400J/KG. SO ALTHOUGH SOME THUNDER IS A POSSIBILITY WITH APPROACHING FRONT AND CONVERGENCE/WEAKENING RRQ OF JET STREAK CROSSING ONTARIO...AND H85 WINDS NEARING 45KT BY EVENING...LACK OF SFC-H85 MOISTURE SHOULD LIMIT COVERAGE/INTENSITY. OTHERWISE...TEMPS GENERALLY LOOK ON TRACK FOR FA. IN IMMEDIATE SHORELINE LOCATIONS ALONG LK SUPERIOR IN MQT COUNTY COULD BE A SLIGHT LAKE BREEZE DEVELOP AS LAND/LAKE DLT T/S ARE ALREADY APPROACHING 20C...HELPING TO OFFSET BLYR/H95 WINDS AROUND 20KT. 15Z OB FM PRESQUE ILSE SHOWING CALM WIND...USUALLY A SIGN OF ERLY LK BREEZE COMPONENT TRYING TO ASSERT ITSELF. WILL NOT MENTION ANY COOLER NEAR LAKE WORDING IN ZONES AS AFFECT SHOULD BE CONFINED TO LESS THAN A MILE OR SO INLAND...WITH SW GRAD FLOW OVERCOMING LK BREEZE IN MOST OTHER LOCALES. ONLY PRIMARY CHANGES BESIDES DELAYING TIMING OF PRECIP OVR ERN ZONES WAS TO FRESHEN WIND WORDING AS MIXING (WHICH SHOULD PRODUCE SFC WINDS GUSTING TO NEAR 30 MPH) IS NOW ONGOING AND SHOULD CONTINUE FOR REMAINDER OF AFTN. .MQT...NONE. JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 955 AM EDT MON APR 30 2001 CLOUDS EAST OF MTNS WILL BE WITH US FOR MUCH OF DAY... BUT RUC SOUNDINGS INDCT THAT ENOUGH MIXING SHUD OCCR DURG AFTN SO THAT PTLY CLDY FCST WILL BE ADEQUATE. CURRENT CLOUD-FREE CONDS OMTNS WILL BCM PTLY CLDY DURG AFTN AS HEATING CONTRIBUTES TO DVLPMNT OF SOME CONVECTIVE CLDNS. CURRENT LOW CHC POPS CNTRL MTNS WILL BE LEFT INTACT. WNDS THRU DEEP LYR VRY LGT SO ANY SHWRS THAT DVLP WILL RMN NRLY STNRY. NO IMPORTANT CHGS TO AFTN MAX TEMPS EXPCTD ATTM IN LATE MRNG FCST ISSUANCE. .GSP... GA...NONE. NC...NONE. SC...NONE. LGL sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 902 AM EDT MON APR 30 2001 SATELLITE LOOP SHOWS CLOUDS INCREASING OVER CAE CWA. AFTER LOOKING AT RUC AND MESOETA SURFACE AND H8 PROGS...HAVE DECIDED IT WILL REMAIN MOSTLY CLOUDY TODAY. NO PRECIP THOUGH. MODELS SHOW GOOD LOW LEVEL MOISTURE CONVERGENCE UNTIL ABOUT 00Z THIS EVENING. WILL CUT HIGH TEMPERATURES A COUPLE OF CATS AS WELL. WILL TRY TO BLEND MOSTLY CLOUDY FORECAST INTO BECOMING MOSTLY CLEAR THIS EVENING AND KEEP SAME LOW TEMPERATURES. OTHERWISE WINDS LOOK OK. FCSTID = 7 CAE 72 52 82 53 / 0 0 0 0 AGS 73 50 82 52 / 0 0 0 0 SSC 72 52 81 52 / 0 0 0 0 OGB 73 53 82 53 / 0 0 0 0 .CAE... GA...NONE. SC...NONE. TTH sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 430 PM EDT MON APR 30 2001 MAIN FCST CONCERNS THIS PACKAGE AGAIN INCLUDE PCPN CHANCES/TIMING ALONG WITH TSRA POTENTIAL TONIGHT AND TUES NIGHT. WV IMAGERY AND RUC ANALYSIS INDICATED RDG OVER ERN NOAM WITH MORE ZONAL FLOW FROM PAC NW TOWARD THE PLAINS. WRN GRT LAKES WAS IN SW FLOW AHEAD OF PROGRESSIVE TROUGH TO THE WEST DRIVEN BY 120 KT H3 JET INTO THE NRN PLAINS. ADDITIONAL JET ENERGY WAS MOVING ONSHORE INTO THE PAC NW. BAND OF SHRA FROM NE MN INTO WRN IA WAS SUPPORTED BY LLVL CONVERGENCE ALONG WEAK FRONT AND SOME H3 DIV WITH RIGHT ENTRANCE OF JET OVER WRN ONTARIO. DIMINISHING PRES RISES BEHIND THE FRONT SUGGEST CONTINUED SLOW EASTWARD PROGRESS. SO FAR...ONLY TSRA NOTED WERE OVER IA CLOSER TO BETTER INSTABILITY. EVEN WITH TEMPS INTO THE LO TO MID 80S F...DEWPOINTS WERE GENERALLY IN THE MID 40S LEADING TO CAPES AOB 500 J/KG. WHERE DEEPER MIXING HAS OCCURRED...TD HAVE FALLEN INTO THE 20SF (KSAW...KEGV). KMQT VAD WINDS SHOWED 30-35 KT 1-2K AGL WINDS. STRONG INSOLATION HAS DRIVEN ENOUGH MIXING FOR MUCH OF THAT TO BE TRANSFERRED TO THE SFC...WITH GUSTS TO NEAR 40 MPH OVER CNTRL UPR MI. TONIGHT...EXPECT PCPN TO CONTINUE GRADUAL SPREAD TO THE EAST INTO WRN UPR MI THIS EVENING (21Z-03Z) AND CNTRL/EAST OVERNIGHT (01Z-06Z)...PER RADAR TRENDS AND 18Z RUC. AS FRONT CONTINUES TO DISSIPATE...PCPN COVERAGE SHOULD BE ONLY SCT AT MOST BY THE TIME IT REACHES CNTRL UPR MI WITH QPF AMOUNTS DROPPING OFF SIGNIFICANTLY. GIVEN CURRENT TRENDS...WITH LACK OF CONVECTION AND NO UPSTREAM FEATURE TO SIGNIFICANTLY STRENGTHEN MOISTURE INFLOW OR UPWARD MOTION...WL DOWNPLAY THUNDER AND MENTION ONLY FOR SW. INCREASING CLOUDS LATE THIS AFTERNOON AND DIURNAL STABILIZATION SHOULD ALLOW THE WINDS TO DROP OFF QUICKLY THIS EVENING. TUESDAY...WL REMOVE PCPN AS ETA/AVN SUGGEST SUBSIDENCE OVER THE AREA WITH SHRTWV RDG AHEAD OF DEEPENING NRN PLAINS TROF. TEMPS SHOULD AGAIN CLIMB WELL ABV NORMAL WITH H8 TEMPS OF 12C-14C SUPPORTING READINGS TO NEAR 80 F. TUESDAY NIGHT...MUCH STRONGER FRONT MOVES THROUGH WITH BETTER CHANCE FOR SCT SHRA. WHILE ETA CAPE MAY AGAIN BE OVERDONE...VALUES APPROACHING 1000 J/KG ALONG WITH VIGOROUS MID LVL WIND FIELDS ENOUGH FOR SLGT SVR THREAT...PER SPC. WEDNESDAY...ETA AND AVN AGAIN DISPLAY LARGE DIFFERENCES WITH RESPECT TO WX FOR UPR MI. WL GO WITH MORE CONSISTENT AVN (BACKED UP BY UKMET/CANADIAN) H5 SCENARIO WITH SHRTWV FARTHER NORTH INTO WRN ONTARIO. ETA H5 SHRTWV POSITION LEAVES UPR MI IN DRY WEDGE WED...WHILE AVN SHOWS POTENTIAL FROM PCPN WITH WEAK SHRTWVS MOVING INTO THE WRN LAKES WITH ISENTROPIC LIFT AND OVERRUNNING OF WEAK FRONT TO THE SOUTH. AVN SHOWALTER AND SFC LI SUGGEST MAINLY SHRA WITH CONVECTION WELL TO THE SOUTH. EXTENDED...MRF/UKMET/ECMWF WERE IN REASONABLE AGREEMENT INTO THIS WEEKEND AS ECMWF HAS TRENDED TOWARD FASTER PROGRESSION OF FRONT TO THE SOUTH OF UPR MI BY FRI. SO...WL TAKE OUT MENTION OF PCPN FRI WITH BULK OF THE DAY PTSUNNY AS SFC HI PRES SETTLES IN. AREAS ALONG LK SUPERIOR...IN PARTICULAR WILL BE NOTICEABLY COOLER (CLOSER TO MEX GUIDANCE) WITH NRLY SFC FLOW. SFC HI WILL DOMINATE OVER THE WEEKEND WITH DRY WEATHER AND MOSTLY CLEAR SKIES. WL HOLD OFF ON ANY PCPN FOR MONDAY AS MRF MAY BE A BIT FAST WITH PROGRESSION OF WRN CONUS LO. PLENTY OF UNCERTAINTY BY DAY 7 THOUGH WITH WIDENING ENSEMBLE SPREAD AND MDL DIFFERENCES WITH NRN STREAM JET ENERGY OR KICKER TO AID PATTERN PROGRESSION. .MQT...NONE. JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTH PLATTE NE 220 PM CDT MON APR 30 2001 ...FORECAST CHALLENGE WILL BE POPS THIS EVENING THEN TEMPS TUESDAY... FEW CLOUDS ACROSS THE NORTH WITH CIRRUS SHIELD TO THE WEST AT 18Z AND NO REFLECTIVITY RETURNS ON THE KLNX 88D. THE HAND SURFACE ANALYSIS SHOWED A TROUGH EXTENDING WEST ACROSS THE SANDHILLS FROM LOW CENTER NEAR OFK. SEMI STATIONARY FRONT EXTENDED SOUTHWEST FROM NEAR DLH...TO ORC...OFK...HSI...LNX...DDC AND TO THE TEXAS PANHANDLE SOUTH OF DHT. WATER VAPOR IMAGERY LOOPS SHOWS DRYING IN THE NORTHWEST IN AREA OF INCREASING SUBSIDENCE. MODELS SHOW VARIATIONS IN POSITION OF SURFACE BOUNDARIES OVER THE PLAINS THROUGH THE FIRST 24 HOURS THEN REMAIN SIMILAR THROUGH 60 HOURS BEYOND PRECIPITAL AMOUNTS. MESOETA AND RUC USED THROUGH FIRST 24 HOURS THEN BLEND OF ETA/AVN BEYOND. STEEP LAPSE RATES IN THE WEST WILL DECREASE FOR THE REST OF THE AFTERNOON AS SUBSIDENCE INCREASE ACROSS THE WEST. COOLER AIR FILTERING IN FROM THE NORTHWEST WILL KEEP BEST CHANCE OF SHOWERS TO BE IN THE EXTREME EASTERN PORTIONS OF THE FORECAST AREA FROM 5 TO 8 PM THIS EVENING. LAPSE RATES IN 700-500 MB LAYER INCREASE TO 7.25 C/KM WITH INCREASED DIVERGENCE AS H5 SHORTWAVE MOVES EAST. LOW LEVEL CONVERGENCE INCREASES OVER HOLT AND BOYD COUNTIES WITH SURFACE LOW OVER EASTERN NEBRASKA. BY 01/00Z THE H5 WAVE MOVES EAST AND SUBSIDENCE INCREASES ACROSS THE NORTH CENTRAL WITH CHANCE FOR SHOWERS ENDING. SURFACE WINDS TURN TO THE SOUTHWEST BY MIDNIGHT AS AREA OF LOW PRESSURE DEVELOPS IN RESPONSE TO NEAR ZONAL FLOW ALOFT ACROSS THE NORTHERN PLAINS AND H3 JET INCREASING DIVERGENCE ALOFT. TEMPERATURES OVERNIGHT WILL MAINLY BE IN THE 40S WITH GUIDANCE CLOSE. TUESDAY TEMPERATURES WILL BE THE MAIN CONCERN AS A COLD FRONT DESCENDS SOUTH INTO THE NORTHWEST DURING THE MORNING...PUSHING SOUTHEAST THROUGH ONL...BBW AND IML BY 1 PM CDT. FEW CLOUDS WILL ACCOMPANY THE INITIAL FRONTAL PASSAGE WITH THE MAIN ENERGY REMAINING ACROSS THE NORTHERN PLAINS. HOWEVER AFTERNOON HEATING WILL RESULT IN STEEPENING LAPSE RATES TO OVER 8 C/KM AS FRONT MOVES TO ALONG THE KANSAS/NEBRASKA STATELINE BY 02/00Z IN THE SOUTHWEST. MOISTURE WILL BE LIMITED WITH ANY CONVECTION HOLDING OFF TILL EVENING AND FOCUS ACROSS THE SOUTHWEST. THEN AS CONVERGENCE INCREASES ALONG AND NORTH OF THE FRONTAL BOUNDARY CLOUDS INCREASING OVERNIGHT AND THE BEST CHANCE FOR PRECIP ACROSS THE SOUTH. THE FRONT CONTINUES TO PUSH SOUTHEAST THROUGH CENTRAL KANSAS TUESDAY NIGHT WITH A SURFACE RIDGE AXIS TO EXTEND EAST ACROSS THE FORECAST AREA. THE H3 JET REMAINS EAST WEST ACROSS THE AREA INTO WEDNESDAY WITH THE SEMI STATIONARY FRONT TO BACK WEST TO THE LEE OF THE ROCKIES WHERE UPSLOPE FLOW WILL GENERATE WIDESPREAD CLOUD COVERAGE AND CHANCE OF SHOWERS INTO THE SOUTHERN PANHANDLE. THE BROAD H5 FLOW WILL HAVE EMBEDDED WAVES WITH THE POTENTIAL FOR STORMS TO MOVE IN FROM THE SOUTHWEST DURING THE OVERNIGHT HOURS WITH INCREASED DIVERGENCE ALOFT. GUIDANCE CLOSE AND FOLLOWED. EXTENSIVE CLOUD COVERAGE COVERS THE SOUTH INTO WEDNESDAY AND WILL LIMIT TEMPERATURES WHILE THE NORTH SEES SOME SUNSHINE WEDNESDAY AND WARMER READINGS IN THE 60S. WEAK HIGH PRESSURE WILL RIDGE NORTHEAST DURING THE DAY WITH PARTLY SUNNY SKIES. MODELS HAVE BACKED OFF WITH COOLER GUIDANCES WITH BLEND USED. IN THE EXTENDED H25 JET REORIENTATES THEN TAKES A DIVES SOUTHEAST ALONG THE WEST COAST AND CARVES AN H5 TROUGH OUT ON THURSDAY. THE H5 LOW CLOSES OFF AND BECOMES DISPLACED FROM THE MEAN FLOW FOR THE REST OF THE PERIOD GRADUALLY LIFTING NORTHEAST THROUGH SUNDAY NIGHT. THE CLOSED SYSTEM OPENS MONDAY WHILE MOVING EAST ACROSS THE PLAINS. THURSDAY A SURFACE FRONT WILL BE TO THE SOUTHEAST AND BEGIN TO STALL AS HIGH PRESSURE BUILDS IN FROM THE NORTH. THE CONVERGENCE BETWEEN THESE TWO SURFACE FEATURES WILL RESULT IN INCREASED CLOUDS AND A CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY... A SERIES OF H5 WAVES WILL ROTATE NORTH ACROSS THE FORECAST AREA AS THE H5 LOW LIFTS NORTH ACROSS THE ROCKIES. THEN SUNDAY THE SURFACE HIGH BUILDS SOUTHEAST INTO THE OHIO VALLEY WITH A SURFACE LOW TO FORM ALONG AN INVERTED TROUGH IN THE SOUTHWEST AND MOVE NORTHEAST THROUGH MONDAY MORNING. KEEPING A CHANCE FOR RAIN OR SHOWERS INTO MONDAY BEFORE THE SYSTEM EXITS EAST. THE EXTENSIVE CLOUD COVERAGE AND RAINFALL WILL LIMIT HEATING BUT WILL STICK WITH GUIDANCES AS LITTLE RANGE MAY OCCUR EACH DAY. .LBF...NONE TLK ne