EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
320 AM PDT MON AUG 23 1999
A WEAK UPPER TROUGH OF LOW PRESSURE OFF THE CALIFORNIA COAST AND
BROAD HIGH PRESSURE OVER THE INTERIOR WEST WILL BRING WEAK SOUTHERLY
FLOW ALOFT AND WEAK ONSHORE LOW LEVEL FLOW TO SOUTHERN CALIFORNIA
THROUGH MID WEEK. A MINOR SURGE OF MONSOONAL MOISTURE WILL BRING A
CHANCE OF THUNDERSTORMS TO THE MOUNTAINS AND DESERTS TODAY.
SYNOPTIC PATTERN IMPACTING SRN CA WL CHANGE LITTLE DURG THE NEXT FEW
DAYS WITH A WK UPPER TROUGH OFF THE CA CST WITH BROAD HIGH
PRESSURE OVER THE INTERIOR WEST. THIS WL RESULT IN WK SLY FLOW ALF
OVR SRN CA WITH WK ONSHR FLOW. HOWEVER...SUBSYNOPTIC DETAILS SHOULD
RESULT IN PERCEPTIBLE DAY TO DAY DIFFERENCES.
FIRST ITEM OF CONCERN IS THE INFLUX OF MOSTLY MID LVL MONSOONAL MSTR
INTO SRN CA TODAY. 03Z ETA IS WELL-INITIALIZED AND PREFERRED. MSTR
ASSOCD WITH ONGOING THUNDERSTORMS OVR FAR SW AZ WL REMAIN ALG AND E
OF THE MTNS TODAY. MTSR ASSOCD WITH THUNDERSTORMS OVR NW MEXICO SUN
EVENING WL BE DRAWN NORTHWARD INTO SRN CA TODAY ALG AND W OF THE
MTNS. ETA BRINGS A SWATH OF 70+ PERCENT RH AT 500 MB NORTHWARD
ACROSS SRN CA ALG AND W OF THE MTNS TODAY. WL CHANGE WORDING FOR
CSTL SXNS TODAY TO PARTLY CLOUDY AFTER MORNING LOW CLOUDS TO ACCOUNT
FOR THIS BRIEF INFLUX OF MID LVL MSTR. FOR MTNS AND DESERTS...WL
INCR POPS TO LOW END OF CHANCE CATEGORY TODAY TO ACCOUNT FOR THE
INFLUX OF MSTR...KPG HIGHEST POPS IN THE MTNS. BOTH RUC AND ETA
GENERATE QPF TODAY ALF THE MTNS FROM THE SBD MTNS S. ETA ACTUALLY
GENERATES QPF FOR SAN COUNTY MTNS AS EARLY AS THE LATE MORNING...
HENCE WL REMOVE TIME QUALIFIERS FOR THUNDERSTORMS TODAY FOR THE SAN
COUNTY MTNS. WL LEAVE THUNDERSTORM WORDING FOR TUE UNCHANGED FOR NOW.
MARINE LYR...SUN EVENING ACARS SOUNDINGS/RAOBS SHOWED A MARINE LYR
DEPTH OF AROUND 700 FT LAX...TO 1500 FT NKX. WITH LTL CHANGE IN
HEIGHTS ALF OVR SRN CA THE NEXT FEW DAYS...EXPECT ONLY MINOR DAY TO
DAY CHANGES IN THE MARINE LYR DEPTH THRU MID WEEK. MDLS ARE ABSENT
SYNOPTIC SUPPORT FOR A CSTL EDDY THRU TUE. HIGHER RESOLUTION MDLS
SHOW ONLY WK ONSHR FLOW AND NO CSTL EDDY. EXPECT CONTINUATION OF
LATE NIGHT/EARLY MORNING LOW CLOUDS AND FOG WITH PATCHY DENSE FOG
INLAND ORANGE COUNTY CSTL PLAIN...SAN COUNTY CSTL MESAS...AND LWR
CSTL VLYS OF SAN COUNTY.
TEMPERATURES...WITH MDTLY HIGH HEIGHTS ALF AND VRY WK ONSHR FLOW...
HIGH TEMPERATURES SHOULD BE SEASONABLY HOT FM THE VLYS INLAND WITH
COOLER HIGH TEMPERATURES CONFINED TO AREAS CLOSE TO THE CST.
SAN 000
.SAN...NONE.
MARTIN
FXUS66 KLOX 231004 ca
EAST CENTRAL FLORIDA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MELBOURNE FL
800 PM EDT MON AUG 23 1999
DOPPLER RADAR LOOP INDICATING THAT EXCEPT FOR LINGERING SHOWERS AND
STORMS OVER NORTH LAKE AND VOLUSIA COUNTIES...DAILY CONVECTIVE
ACTIVITY DISSIPATING. LATEST RUC MODEL MAINTAINS AN AREA OF
VORTICITY OVER THE SOUTHERN PORTION OF THE COUNTY WARNING AREA. WILL
WAIT A WHILE LONGER AND MOINTOR TRENDS HOWEVER...WE WILL REMOVE
PRECIPITION CHANCES LATER THIS EVENING.
MARINE...WILL MAKE LITTLE CHANGES OTHER THAN BUMPING UP WINDS A
LITTLE FOR TONIGHT AS PER RECENT TRENDS OF BUOYS 9 AND 10.
.MLB...NONE.
WIMMER/TROUTMAN
FXUS62 KTBW 232338 fl
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSONVILLE FL
945 AM EDT MON AUG 23 1999
CONVECTION IS OCCURRING OVER THE ATLANTIC WATERS. VISIBLE SATELLITE
IMAGERY SHOWS FOG AND LOW CLOUDS FROM NORTHERN DUVAL COUNTY AND THE
OKEFENOKEE NORTHWARD THROUGH MUCH OF OUR GA CWA.
STORMS WHICH DEVELOP TODAY WILL HARDLY MOVE. KJAX 12Z SOUNDING SHOWS
AN UNMODIFIED CAPE OF 3200 J/KG. THE WET BULB ZERO IS 12.6 KFT WHICH
IS LOWER THAN IT HAS BEEN MOST OF THE SUMMER. BOTTOM LINE IS WE CAN
EXPECT STRONG STORMS WITH HEAVY RAINS AND LOCALIZED FLOODING. WILL
DROP THE POPS A CATEGORY IN GA AS CHANCES FOR PRECIP SHOULD BE
GRADUALLY INCREASE FROM NORTH TO SOUTH OVER THE AREA.
NORTH WINDS AT GRAYS REEF HAVE SHIFTED TO NNE. RUC MODEL INDICATES
THEY WILL BE EAST THIS AFTERNOON...SO WILL TWEAK THE CWF
ACCORDINGLY.
MKT
FXUS72 KMFL 231326 fl
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
305 AM CDT MON AUG 23 1999
06Z MSAS AND SFC ANALYSIS INDICATED LOW PRESSURE CENTER ACRS WEST
CENTRAL MN WITH FRNTL BOUNDARY EXTENDING SOUTHWEST ACRS EAST SD
AND INTO NE. THIS FEATURE SFC REFLECTION OF VIGOROUS UPPER WAVE
THAT CURRENT W/V LOOP IS INDICATING NICELY OVER NORTHEAST ND. W/V
LOOP ALSO INDICATING MUCH WEAKER LEAD VORT ACRS SOUTHERN WI AND
PORTIONS OF NORTHEAST IA. THIS SMALLER VORT AND IT/S ASSOCIATED
FORCING HELPING TO INDUCE ONGOING PRECIP ACRS KDVN CWA ATTM...WHICH
BY THE WAY 00Z RUN SHORT RANGE MODELS ARE DOING POORLY WITH. 00Z H5
UA ANALYSIS ALSO DISPLAYS THESE TWO VORT CENTERS NICELY...AND AS
ADJACENT SHORTWAVE EXITS TO THE EAST...MAIN UPSTREAM WAVE TO BE MAIN
PLAYER FOR MONDAY/S WX. BACK TO THE SFC...MSAS INDICATING MOISTURE
AXIS OF 65+ DPTS EXTENDING FROM CENTRAL MN ON SOUTHWARD ACRS THE WEST
HALF OF IA AND NORTHWEST MO. MOISTURE CONVERGENCE NORTH OF WEAK
SFC TROUGH ACRS NORTHERN MO AIDING PRECIP ACRS SOUTHEAST IA ATTM. SFC
THERMAL AXIS ALSO BUILDING AS 70+ AMBIENT TEMPS NOTED ACRS FAR
SOUTHERN IA...KS AND MO. STRONG SFC PRES FALLS CONTINUING WHERE THEY
SHOULD ACRS CENTRAL MN...WITH ANOTHER FALLS BULLSEYE NOTED ACRS SOUTH
CENTRAL IA AND NORTHERN MO.
SHORT RANGE MODELS INITIATED DECENTLY WITH UPPER FEATURES...AND W/V
IMAGERY INDICATING MODELS DOING WELL WITH VORT STRENGTH AND
PLACEMENT AS WELL. MODELS HAVE COME TOGETHER IN HANDLING VIGOROUS
UPSTREAM WAUE IN STRENGTH AND POSITIONING THROUGH THE PERIOD. BY
18Z MON...MODELS SIMILAR WITH WAVE PUSHING ACRS THE SOUTHERN HALF
OF MN WITH IMPRESSIVE UPPER DIFFLUENCE TAKING PLACE ACRS THE MID
MISS RVR VALLEY. STRONG PVA STARTS TAKING PLACE ACRS EASTERN IA
WITH ETA AND NGM REASONABLY SIMILAR...AVN LAGS BEHIND SOMEWHAT.
OVERNIGHT...CLOSED UPPER LOW TRAVERSES ACRS EAST IA AND MAKES ITS
WAY TOWARD THE SOUTHERN HALF OF IL ON TUE. THIS CLOSED UPPER SYSTEM
THEN BOGS DOWN LATE ON TUES AS IT APPROACHES THE OH RVR VALLEY.
AS ONE WOULD THINK...SYSTEM THIS VIGOROUS WILL INDUCE STRONG
VERTICAL VELOCITIES WITH UPPER SPEED MAX ROTATING SOUTHEAST OUT OF
SASK AIDING IN THE PROCESS. BY 18Z MON...STRONG H85-H5 QG FORCING
MAXIMUM BUILDS OVER EAST IA AND SHIFTS ACRS WEST CENTRAL-CENTRAL IL
BY 00Z TUE...THEN CONTINUES TO SLIDE EAST-SOUTHEAST INTO TUE
MORNING. LOOKING AT THERMAL/MOISTURE PARAMETERS FOR STRONGER
THUNDERSTORMS...IT APPEARS SOUTHEAST IA INTO WEST CENTRAL IL MORE
AT RISK FOR SUBSTANTIAL TSRA/S THIS AFTERNOON. BY 18Z...ETA BRINGS
1600-2K J/KG SBCAPE RIBBON ACRS EAST CENTRAL AND SOUTHEAST IA...AND
BY 00Z TUE BEST CAPES ARE ACRS SOUTHERN KS INTO MO...ALTHOUGH WE
WILL NEED SOME BREAKS IN THE CLOUD COVER TO ACHIEVE THESE VALUES.
LINGERING 1300-1600 J/KG CAPES FCST TO CONTINUE ACRS FAR SOUTHEAST IA
AND WEST CENTRAL IL AROUND 00Z TUE. BETWEEN 18Z MON-00Z TUE...BEST
H85 THTA-E ADVECTION OCCURS ACRS MO INTO SOUTHEAST IA ALONG WITH H85
THTA-E RIDGE AXIS. BETTER INSTABILITY AXIS SETS UP ACRS SOUTH CENTRAL
IA INTO MO...ALTHOUGH 20 KT LLJ FEEDS MOST OF EASTERN IA WITH NICE
H85 MOISTURE FLUX. H85-H7 UVV BULLSEYE ALSO ACRS MOST OF EAST IA THIS
AFTERNOON...BUT ALL THESE PROCESSES SHIFT SOUTH AND EAST AS THIS
EVENING PROGRESSES. INCREASED LOW TO MID LEVEL MOISTURE CONVERGENCE
ALSO TO BE A FACTOR AND MOST OF CWA OPEN TO SOME TSRA DEVELOPMENT
THIS AFTERNOON...JUST FEEL SOUTHERN THIRD OF CWA MORE PRONE TO
SUBSTANTIAL STORMS IF INSTABILITY PARAMETERS ARE ALLOWED TO BE MET
WITH SOME HEATING...AND WITH LATEST RUC CONTINUING TO PUMP MOISTURE
ACRS CWA...MAY BE A QUESTION.
AS SYSTEM BOGS DOWN TO THE SOUTH ON TUESDAY...FEEL AREA WILL BE UNDER
THE INFLUENCE OF UPPER CYCLONIC FLOW...WRAP AROUND CLOUDS...RAIN/
DRIZZLE...AND A NORTHERLY WIND. ALL THIS LENDS TO FWC AND EVEN FAN
NUMBERS BEING TOO OPTIMISTICALLY WARM.
.DVN...
IA...NONE.
IL...NONE.
JDH
FXUS63 KILX 230810 il
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1025 PM EDT MON AUG 23 1999
01Z SFC ANALYSIS SHOWS THE COLD FRONT AND LOW DROPPING INTO THE OHIO
VALLEY. A LINE OF SHOWERS AND THUNDERSTORMS ACCOMPANY THIS FEATURE WITH
AN IMPRESSIVE LOOKING VORT SWIRL ON THE WV SATELLITE LOOP. EARLIER
SOUTHERN VORT HAS MOVED EAST TAKING THE THUNDERSTORMS ALONG WITH IT. WE
WILL SEE PARTLY CLOUDY SKIES FOR THE REMAINDER OF THE NIGHT. THE
MESOETA AND RUC BOTH TRY TO REDEVELOP PRECIPITATION ACROSS BY 09Z. I
DON T BUY THAT AS LAPS AND MSAS DATA SHOW MORE STABLE THAN NOT AIR
ACROSS MOST OF THE CWA. HOWEVER...AS EVIDENCED BY THE SHOWER MOVING
NORTHWEST OF FLEMING COUNTY A SHOWER IS POSSIBLE AT ANYTIME IN THIS
ENVIRONMENT. THE BEST RAINS WILL HOLD OFF UNTIL THE UPPER LEVEL VORT
AND ENERGY GETS CLOSER...AFTER 12Z. AS IT STANDS THE CURRENT OVERNIGHT
FORECAST IS IN PRETTY GOOD SHAPE DESPITE THE COMPLEX SITUATION COMING
TOGETHER FOR THUNDERSTORMS LATER TUESDAY. WILL ISSUE AN UPDATE MAINLY
FOR WORDING WITH THE THEME SIMILAR.
UPDATED ZONES OUT SHORTLY.
.JKL...NONE.
GREIF
FXUS63 KJKL 231926 ky
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
230 PM CDT MON AUG 23 1999
MODELS ARE STILL POINTING TO A 30 PERCENT-TYPE RAIN EVENT THAT
EXTENDS ALONG THE ENTIRE I20 CORRIDOR. NGM FWC NUMBERS ARE 30 PCT...
AND ETA AND NGM FOUS GIVES QPF OVERNIGHT AT SHV. MAIN FOCUS IS
TONIGHT AND TUESDAY WITH PASSAGE OF VORTICITY AXIS AND SURFACE
BOUNDARY. SFC DEWPOINTS HAVE MOISTENED UP ACROSS MOST OF CWA EXCEPT
NEAR LUFKIN WHERE IT ALREADY WAS STICKY. TEMPS ALL MORNING HAVE BEEN
HIGHER THAN 24 HOURS AGO. SHOWN THAT RUC POINTS TO DECENT MOISTURE
FLUX CONVERGENCE FROM FORT SMITH TO WICHITA FALLS THIS EVENING. THIS
IS INTERESTING IN THAT MY MAIN POPS CONCERN TONIGHT IS THE TEXAS
PORTION OF THE I20 CORRIDOR...WHERE I HAVE A BIT OF A HARD TIME
JUSTIFYING CHANCE POPS GIVEN BY THE NGM. MAYBE THE RUC IS ON TO
SOMETHING. EVEN SO...CAN THIS SYSTEM IF IT DEVELOPS MAKE IT FAR
ENOUGH SOUTH OVERNIGHT. I THINK I WILL GO LOWER THAN GUIDANCE AND
SAY 20 PERCENT FOR GGG/TYR TONIGHT.
20 PCT POPS THIS EVENING NEAR LFK IN CASE OF OUTFLOW BOUNDARIES FROM
EARLIER CONVECTION TO THE SW. BUT A BREATHING-IN PERIOD OVERNIGHT FROM
BRET WILL NOT LET CONVECTION LAST LONG THERE THIS EVENING.
POSITION OF SFC TROF IS A CONSIDERATION TOMORROW FOR UPPING MAX
TEMPS IF IT WEREN/T FOR THE POSBL CLOUDS AND SHOWERS. WILL GO HIGHER
THAN GUIDANCE SOUTHERN TIER TUESDAY...AND OVER SRN AR/SE OK. IT IS
ALONG AND AHEAD OF TROF/FRONT THAT PERHAPS ANOTHER BATHC OF TSTMS
WILL FIRE...GIVEN THE SLGT RISK FOR FAR NRN LA AND SRN AR ON THE
SECOND DAY OUTLOOK. GIVEN THE MARGINALITY OF THIS...WILL NOT MENTION
A /SOME POSSIBLY SEVERE/ WORDING. BUT POPS FOR MLU AREA WILL BE THE
CONSISTENTLY HIGHEST IN MY PRODUCT.
BY 48 HOURS WE WILL HAVE AN UPPER TROF TO NE AND UPPER RIDGE TO NW.
N/NW FLOW ALOFT ALWAYS HAS POTENTIAL TO SURPRISE US...BUT THERE IS
ALSO A NORTHERLY FLOW AT SURFACE. THIS CAUSED THE MRF TO DROP POPS
LOW ENOUGH TO NIL THEM OUT FOR WED AND THURSDAY EXCEPT DOWN SOUTH
WEDNESDAY. SO SUGGEST EVENING SHIFT ADD THURSDAY TO THE DRY DAYS IN
THE EXTENDED AND THEN REINTRO SLIGHT CHANCES FOR SATURDAY. 17
PRELIM GUESSES...
SHV 73/96/72/95 2320
MLU 73/96/70/95 3330
TXK 71/97/69/95 3320
TYR 72/96/70/96 2220
LFK 74/97/73/96 2322
.SHV...NONE.
FXUS64 KLIX 231917 la
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
915 PM EDT MON AUG 23 1999
LTST ANALYSIS SFC AND ALOFT WUD SUGGEST PTTN WILL REMAIN ABOUT STATUS
QUO OVRNGT AS SUGGESTED BY THE 21Z RUC. WEAK S/W IN H5 FLOW FCST TO
DRIFT ACRS VA AND VCNTY ALONG WITH HI LAYERED RH FIELD TO GENERATE
ISOLD SHWRS AND PERHAPS SOME SMALL TSTMS UNTIL SHORTLY AFTER MIDN.
SAT IMAGERY DEPICTS PC TO MC ACRS THE CWA WITH ADDITIONAL AREAS OF
CLDINS HEADED THIS WAY FROM THE UPR OH VLY. MAY HAVE TO ADJUST TEMPS
UP A BIT DUE TO CLD CVR OVRNGT. OTW WILL GO WITH A SLGT CHC OF A SHWR
OR TSTM ACRS THE BOARD.
IN THE TROPICAL DEPT THE FEATURE N OF PUERTO RICO WILL REQUIRE SOME
ATTENTION THE NEXT FEW DAYS. ERLR 12Z AVN APPARENTLY IS FCSTG THIS
DVLPG SYSTEM TO MOVE NW AND BE LOCATED WELL SE OF THE SE CST IN 72 HRS.
IT MAY GET CAUGHT UP IN THE SOUTHERLY FLOW ALOFT ON THE LEAD SIDE OF
THE CLOSED LOW MOVING E ACRS THE OH VLY AT THAT TIME.
OTW THAT'S IT FOR NOW...NEXT TIME.
.LWX...NONE.
PAP
FXUS61 KLWX 231842 md
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1015 PM EDT MON AUG 23 1999
LATEST SATELLITE AND KAPX RADAR CONTINUE TO SHOW PRECIP DIMINISH AS
IT ENTERS SOUTHWESTERN ZONES. RUC AND LATEST ETA SUGGEST BEST
FORCING TO TO OUR SOUTH THROUGH THE OVERNIGHT. SATELLITE AND RADAR
IMAGERY IN SUPPORT OF THIS. THEREFORE WILL DROP POPS TO 30 PERCENT
IN FAR SOUTHWEST ZONES. WILL ALSO DROP SCATTERED WORDING IN FAR
NORTHERN LOWER ZONE TO ISOLATED SHOWER...AND WILL DROP SCATTERED TO
ISOLATED SHOWERS IN ALCONA...CRAWFORD AND OSCODA COUNTIES. SATELLITE
AND SURFACE REPORTS ALSO INDICATING MUCH OF NORTHERN LOWER UNDER
PARTLY CLOUDY SKIES. WILL THUS DROP MOSTLY CLOUDY WORDING FOR PARTLY
CLOUDY IN FAR NORTHERN LOWER AND NORTHEAST LOWER BREAKOUTS.
.APX...NONE.
CONSIDINE
FXUS63 KAPX 240215 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1010 PM EDT MON AUG 23 1999
FCST CONCERN IN THE SHORT TERM IS POSS OF BR AND -SHRA THRU TMRW
MORN.
00Z SURFACE ANALYSIS SHOWS A 1006MB SFC LOW PRES SYSTEM LOCATED IN
WEST CENTRAL IL. REGIONAL RADAR SHOWS INTENSE SQUALL LINE AHEAD OF
COLD FRONT THAT EXTENDS FROM KORD BACK TO KCOU. AS FAR AS THE U.P.
IS CONCERNED...01Z 88D LOOP IS SHOWING SOME DEVELOPING -SHRA IN NRN
WI AND THESE ARE INFILTRATING THE SRN BORDER COUNTIES. THE SOURCE OF
THIS LIGHT ACTIVITY IS THE QUESTION OF THE HOUR AND WILL IT CONTINUE
ALSO IS A CONCERN.
21Z AND 00Z RUC MODEL POINTS TO AN AREA OF H3 DIVERGENCE BETWEEN 00Z
AND 03Z NORTHEAST OF THE MAIN H5 VORT MAX LOCATED OVER ERN IOWA AND
THIS COULD BE THE SOURCE OF THE -SHRA OR SPRINKLES OVER THE WI
BORDER COUNTIES...ALSO A WEAK VORT MAX/MINI SHORT WAVE IS ROTATING
INTO THE U.P. ON THE FRONT OF THE 500MB TROF PER THE RUC AND 18Z
MESOETA. BELIEVE THAT THE LOW LEVEL MOISTURE AND THESE FORCING
MECHANISMS ARE ALSO CONTRIBUTING TO THE -SHRA OVER THE SRN AND SWRN
U.P. ATTM.
IN THE OVERNIGHT INTO EARLY TUES MORN PERIOD BOTH THE MESOETA AND
RUC BRING ANOTHER VERY WEAK SHTWV INTO THE WRN U.P. BY 12Z FROM THE
NORTHWEST. SCT SHRA IN NC MN ATTM COULD BE ATTRIBUTED TO THIS
FEATURE WHICH SHOWS DIVERGENCE MORE IMPRESSIVELY AT H5 THAN AT H3.
EITHER WAY...MODELS TEND TO WEAKEN THIS SECOND SHORTWAVE AS IT
APPROACHES THE U.P. HOWEVER...AS IT MOVES INTO THE AREA LATE TONIGHT
IT COULD KICK OFF SOME SCATTERED SHOWERS IN THE WRN ZONES SO WILL
LEAVE FCST AS IT IS...WITH A SCATTERED SHOWERS MENTION. OTHERWISE
WILL DOWNPLAY THE SHOWERS IN THE EAST AS IT APPEARS THE BEST FORCING
WILL NOT EFFECT THAT AREA VERY MUCH..IF AT ALL.
WILL OPEN UP TEMPERATURES TO 60 TO 65 IN THE FAR EAST AND FAR WEST
BASED ON CURRENT TEMPS AND DEW POINTS AS WELL AS THE EXPECTED CLD
COVER.
WILL BUMP POPS DOWN IN THE EAST TMRW MORNING W/ WEAKER FORCING
ANTICIPATED.
COORD WITH APX.
.MQT...NONE.
JLA
FXUS63 KGRR 240137 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1055 AM EDT MON AUG 23 1999
12Z H5 ANAL AND LATEST WV LOOP SHOWS DEEP SHRTWV NR FAR WITH NLY H3
90KT JET MAX AT BIS DIGGING SEWD IN GENERAL NWLY FLOW ALF BTWN UPR
RDG OVR ROCKIES AND MEAN TROF IN ERN CONUS. SFC LO PRES IN SCNTRL MN
BUT APPEARING TO REDVLP FARTHER S ALG COLD FNT STRETCHING INTO CNTRL
PLAINS IN PATH OF MORE SGNFT DYNAMICS AND TOWARD SHARPER 12Z H85
TEMP GRADIENT. SHRA/TSRA AHD OF MN LO PRES HAS BEEN DIMINISHING AS AREA
HAS MOVD EWD LAST COUPLE OF HRS PER COMPOSITE 88D LOOP/DCRSG LGT
STRIKES/WRMG IR CLD TOP TEMPS. THIS TREND CONSISTENT WITH LACK OF
SGNFT LO LVL THERMAL GRADIENT/WND/OVRRNG OVR NRN LKS AND XPCTD TRACK
OF BEST H85-5 QVECTOR CNVGC AHD OF DIGGING SHRTWV. OTRW...LOTS OF LO
CLD OBSVD OVR CWA THIS MRNG WITH SFC DWPTS GENERALLY ARND 62 AND LGT
SLY FLOW AHD OF MN LO PRES. 88D SHOWS SCT -SHRA ARND WITH GENERAL
-SHRA AHD OF LO NOW REACHING IWD...WHICH JUST RPRTD LTG TO NW. LARGE
HOLE IN LO CLD NOTED JUST DOWNWIND OF HURON MNTS OVR SRN LK SUP
WHERE SLY FLOW DOWNSLOPING AND DRYING. 12Z GRB SDNG DEPICTS ABUNDANT
LO LVL MSTR/NRLY MOIST ADIABATIC LAPSE RATE BLO DRY/MORE STABLE LYR
ABV H6-65.
MAIN FCST CONCERNS TDAY CENTER ARND EXTENT OF CLDS/PCPN/TSRA AND TEMPS.
12Z RUC IN GOOD AGREEMENT WITH EARLIER ETA/MESOETA RUNS IN KEEPING
BEST DPVA AHD OF DIGGING SHRTWV AND H85 WAD TO S OF CWA. MODEL
ACTUALLY SLOWLY BLDS H5 HGT AND MAINTAINS LWR H7 RH OVR U.P. WITH
H85-5 QVECTOR DVGC OVR ALL BUT SRN TIER ZNS AS H5 SHRTWV CUTS OFF
AND SFC LO REDVLPS TO S. ALTHOUGH INSOLATION MAY BURN A FEW HOLES IN
LO CLD AND ALLOW TEMPS TO REACH 70-75 RANGE AS FCST BY LATEST LAMP
GUIDANCE...MODIFIED GRB SDNG FOR 75/63 YIELDS ONLY 730 J/KG CAPE
WITH A SML NEGATIVE AREA. GIVEN LACK OF BNDRY...ANY SGNFT DYNAMICS/
OVRRNG AND POTENTIAL THAT LO CLD WL HANG TOUGH AND KEEP TEMPS A BIT
LWR...WL DOWNPLAY PCPN CHCS AND RESTRICT MENTION OF PSBL RUMBLE OF
THUNDER TO WI BORDER ZNS.
GOING TEMPS LOOK OKAY...BUT WL LWR MAX FCST A BIT OVR E GIVEN
EXTENSIVE CLD COVER.
.MQT...NONE.
KC
FXUS63 KDTX 231435 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1030 AM CDT MON AUG 23 1999
FORECAST CONCERN NEAR TERM...RAIN CHANCES.
WATER VAPOR IMAGERY SHOWED CORE OF UPPER LEVEL CIRCULATION ABOUT 30
MILES NORTHWEST OF REDWOOD FALLS MOVING SOUTHEAST. 12Z ETA AND 12Z
RUC AGAIN SHOW 700 MB TEMPERATURES ASSOCIATED WITH UPPER LEVEL
CIRCULATION WARMING THROUGH 00Z TUE. WARMING BEHIND UPPER LEVEL
CENTER HELPING TO STABILIZE THE AIR MASS. BASED ON INCREASING
STABILITY...AND 6 HOUR VS. 12 HOURS FOR THIS AFTERNOON POP...HAVE
LOWERED THE POP FOR THIS AFTERNOON ACROSS MN PORTION OF CWA AND
ADJACENT COUNTIES IN WEST CENTRAL WI. FARTHER EAST...PLENTY OF
FORCING AND STABILITY TO JUSTIFY HIGH POPS FOR RAIN AND
THUNDERSTORMS THIS AFTERNOON.
VISIBLE IMAGERY SHOWED AN ABSENCE OF EXTENSIVE CLOUDS ACROSS MUCH OF
THE WESTERN PORTION OF THE CWA. HOWEVER DAYTIME HEATING SHOULD
INTERACT WITH THE COOL AIR ALOFT TO PRODUCE PARTLY TO MOSTLY CLOUDY
SKIES...CALLED IT VARAIABLE CLOUDINESS.
TRENDS FOR TONIGHT STILL LOOK GOOD FROM EARLIER PACKAGE.
.MSP...NONE.
RJN
FXUS63 KDLH 230838 mn
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
940 PM EDT MON AUG 23 1999
ANOTHER EVNG WITH MULTIPLE SFC HIGHS/RDG PATS IN NRN AND WRN DIST.
FIRST STRAND OF CI NR KOGS-KUCA WHILE BEGINNING OF MORE WDSPRD WAA
PAT CLDS NR KOSC-KIAG-KAVP ARC WITH SFC WRMFNT ATTEMPTING TO MOV
ACRS SRN OH AND THRU ERN WV PNHNDL. RUC SHOWS LTL MOTION TO THAT
FEATURE...BUT DOES DEVELOP PRE-FNTL TROF INVOF ERN GRTLKS BY 09Z.
WITH THAT IN MIND...WL XPC HI CLDS TO BE ACRS AREA S OF KOIC-KPSF
AXIS BY SR. ELSW...MSTLY CLR SHOULD BE USABLE N OF THE LN...BUT WRN
ADRNDCKS WL LEAN TO VRBL HI CLDS. WL EASE OFF ON FOG FCST SRN ZONES
AND WL STAY PUT NRN AND CNTRL SXNS. MCKINLEY/GEW
.ALY...NY ERN/VT EXTRM SRN/MA EXTRM WRN/CT NW...NONE.
FXUS61 KBUF 240103 ny
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
855 PM EDT MON AUG 23 1999
IR AND WV LOOPS SHOW CI SHIELD THICKENING ACROSS THE SW 1/2 OF CWA.
USED 21Z RUC AS A GUIDE TO HOW FAR THE CI WILL MOVE EAST AND NORTH
OVERNIGHT. IT SHOWS A WEAKENING 500 MB SHORTWAVE MOVING THROUGH UPPER
RIDGE OVR CEN NY AND NE PA AND 300MB RH SHOWING CI WILL SHOULD MOVE
INTO THE WRN CATSKILLS 06Z TO 09Z. IT KEEPS THE MID LVLS DRY OVER OUR
AREA.
SO MINOR CHANGES FOR THE EVENING UPDATE. WILL USE PARTLY CLOUDY TNT FOR
THE WESTERN PORTIONS OF THE FA...INCREASING CLOUDS LATE IN THE
EAST...AND MAINLY CLEAR NORTH.
WITH A SUBSTANTIAL HIGH CLOUD LAYER IN PLACE OVER 1/2 FA...HAVE UPPED
TNT MINS SLIGHTLY BY DROPPING THE MENTION OF UPPER 40S AND GENERALLY
FAVORED THE MIDDLE 50S JUST ABOUT EVERYWHERE.
REST OF FORECAST LEFT UNCHANGED.
.BGM...NONE.
CHIARAMONTE
FXUS61 KOKX 240016 ny
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BINGHAMTON NY
200 PM EDT MON AUG 23 1999
CLOUDS AND LIGHT PCPN MOVG ACRS SRN MI INTO NW OH AND MAKING SLOW
PROGRESS TWRD NYS. ACCRDG TO RUC ANALYSIS INITIAL SHOT OF LIFT
DRIVING LGT PCPN RELATED TO WEAK VORT MAX AND 250 MB WAA/PV MAXIMA.
THIS PROGGED TO SLIDE SEWRD ACRS ERN OH INTO WRN PA OVRNGT WHILE
STRONGER PV MAX AND UPPR LVL WAA ASSOCD WITH DIGGING NRN PLAINS DROPS
SEWRD INTO LWR OH VLLY. LOW LYRS RELATIVLY DRY OVR MI/OH AND MOST
OF PCPN HAS BEEN LGT. AS INITIAL FORCG SLIDES SEWRD EXPECT PCPN TO
STAY S AND W OF CWA TNGT. MDLS KEEP LOW LYRS DRY THRU LATE DAY TUES
SO EXPECT ONLY MID/HI LVL CLDS TO MOVE IN LATER TNGT. WILL KEEP IT
MSTLY CLR TNGT AND HAVE INCRSG CLDS LATE...ESP IN WRN CWA.
FOR TMW AND TMW NGT...STRONG NRN PLAINS VORT MAX FCST TO WEAKEN AS
INTITIALLY BAROCLINIC AMS MODIFIES AND BECOMES MORE BAROTROPIC WITH
TIME. JET MAX ON SW SIDE OF SHT WV DIGS SEWRD BUT WEAKENS AS MEAN
TEMP GRAD WEAKENS. INTITIAL STRONG UPPR LVL DIVERGENCE AND LIFT
WITH JET WEAKENS AND BECOMES DIFFUSE AS WEAKENING JET CORE LOOSES
ITS SPEED SHEAR AND TAKES ON A MORE CYCLONICALLY CURVED
CONFIGURATION. BY 36-48 HRS LIFT ASSOCD WITH JET MAX MOSTLY DUE TO
WEAK DIFFLUENT FLOW ALF WITH CURVED JET STRUCTURE. MOST OF Q-VECTOR
FORCG RELATATED TO THIS CURVATURE RATHER THAN SPEED SHEAR AND LIFT
REMAINS CONCENTRATED S AND W OF NYS. ALSO WITH SUCH A BAROTROPIC
AMS THERE REALLY WON'T BE MUCH LOW LVL WAA AHD OF SHT WV TO AID
LIFT. THEREFORE LOW LYRS STAY FAIRLY DRY THRU 00Z/25 SO WILL GO
WITH PTLY CLDY E AND N. IN THE S AND W TMW...TIME-HGT CROSSS
SECTIONS SHOW DEEPER MSTR TWRD LATE DAY AND THERE MAY BE ENUF MSTR
FOR A FEW SHOWERS OR ISOLD TSTM IN THE S. BUFKIT DATA SHOWS ETA
CAPES ARND 650 J/KG BUT NGM INSTABILITY MUCH WEAKER. WILL LEAVE OUT
OF ZNS FOR NOW BUT IF WE GET MORE HTG TMW THERE MAY BE ENUF
CONVECTION FOR SCT POPS. TMW NGT SFC HI OFF ATLANTIC COAST AND SFC
LOW OVR OH VLLY ESTABLISHES STRONG ENOUGH LOW LVL FLOW TO BEGIN
BRINGING IN LOW LVL MSTR TO CWA. PRECIP WTR VALS AND 850 MB MIXING
RATIO INCRS SLGTLY ESP ALNG SPINE OF APPALACHIAN MTNS IN CONFLUENCE
ZN AND THIS ADVECTS NWRD INTO SRN CWA. DESPITE WEAK DYNAMC SUPPORT
FOR LIFT WILL GO WITH SCT POPS OVR SRN CWA TMW NGT BASED ON INCRSG
LOW LVL MSTR AND OROGRPHIC LIFT BUT WILL KEEP CNTRL AND NRN ZNS DRY.
BY WED DEEP LYR MSTR IN PLACE BUT STILL LITTLE DYNAMC FORCG AS SHT
WV CUTS OFF OVR IN/OH AND STALLS. BEST MSTR AND INCRSG LIFT WILL BE
FELT ACRS CNTRL PA AND S BUT FEEL SUPPORT FOR PCPN ACRS SRN CWA WILL
BE INCRSG AS WELL SO WILL GO WITH 40 PCNT THERE AND 30 PCNT CNTRL
AND N. TEMPS WILL BE COOLER ON WED DUE TO MORE CLD CVR BUT GUIDANCE
APPEARS TO BE IN THE BALLPARK.
.BGM...NONE.
HOLMES
FXUS61 KALY 231352 ny
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
945 PM EDT MON AUG 23 1999
EXPECT ONLY MINOR ADJUSTMENTS TO UPCOMING FORECAST PACKAGE UPDATE.
SATELLITE LOOPS DEPICT CLOUD TOPS GRADUALLY WARMING AS UPPER
DYNAMICS BEGIN TO WANE AND CONVECTION MOVES INTO SLIGHTLY MORE
STABLE AIRMASS. 21Z RUC SIMILAR TO 12Z AVN IN DEPICTING VORT CENTER
SHEARING ENE ACROSS VA WHILE SLIGHTLY STRONGER VORT CENTER MOVES ESE
ACROSS TN VLY. APPEARS BEST RAIN CHANCES OVER NIGHT WILL BE WESTERN
SECTIONS OF PIED. SEE LITTLE REASON TO DEVIATE FROM CURRENT POP
FORECAST. WILL LIKELY CONTINUE SLIGHT CHC POPS FOR AREAS IMMEDIATE E
OF WESTERN PIEDMONT FOR OVERNIGHT HOURS AS A FEW STRAY SHOWERS
POSSIBLE IN INCREASING MOIST AIRMASS.
THICKENING CLOUD COVER OVER CWA WILL REQUIRE SLIGHT ADJUSTMENTS
(UPWARD) TO OVERNIGHT TEMPS...MAINLY IN SANDHILLS AND NW PIED.
.RAH...NONE.
WSS
FXUS62 KILM 240131 nc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
930 PM EDT MON AUG 23 1999
LATEST IR IMG DEPICTS WARMING TOPS CORRELATING WELL W/ DECREASE IN
LTG DETECTION AS COVC WEST OF CWFA DISSIPATES. WITH LOSS OF DAYTIME
HEATING AND OROGRAPHIC LIFT I EXPECT THIS PCPN TO CONTINUE TO
SUBSIDE. ESPECIALLY WITH NO REAL UPPER LEVEL SUPPORT. ONE ISOALTED
TSRA OF CONCERN PASSED OVR KSVH AROUND 0015Z BUT IS RAPIDLY LOSING
ITS PUNCH AS IT TRACKS SE. LOOKING AT THE 21Z RUC DATA...IT APPEARS
THE SUPPORT FOR THIS STORM WAS COMPRISED OF H50-H30 DIFF VORT ADV
AND H30-H10 DIV ASSOCIATED W/ UPPER S/W. THE RUC LOSES THESE
SUPPORTING FEATURES RAPIDLY ACRS CWFA BUT REDEVELOPS THEM OFF SHORE.
SO I WILL INTRODUCE ISO POPS ALONG COASTAL COUNTIES W/ THE
ANTICIPATION OF FURTHER DEVELOPMENT OFF COAST AND EXPECTED EAST TO
WEST MOVEMENT. DRY REST OF CWA. NO ADJUSTMENT TO TEMPS.
CWF...NO CHANGES
.ILM...NONE.
JFP
FXUS62 KMHX 240045 nc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1018 AM EDT MON AUG 23 1999
HIGH CENTERED VICINTY DELMARVA PER LATEST SURFACE ANALYSIS WITH AXIS
INTO COASTAL NCAROLINA. HIGH WILL CONTINUE MOVING OFFSHORE TODAY AS
RETURN FLOW BECOMES ESTABLISHED OVER STATE. LATEST RADAR SHOW SMALL
AREA OF SHOWERS JUST WEST OF CWA (LINCOLN/GASTON COUNTIES)...VERY
WEAK FEATURES ATTRIBUTING TO ACTIVITY..MOISTURE CONVERGENCE/SUBTLE
FEATURE AT 700 MB AND WEAK IMPULSE MOVING ACROSS PER 12Z RUC. EXPECT
TO STAY WEST OF CWA...MORNING RAOB SHOW CWA STABLE ENOUGH TO BE NON
EFFECT. WILL WATCH THOUGH. WILL GO MOSTLY/PARTLY SUNNY AS SATELLITE
TRENDS SHOW SOME CLOUDS MOVING IN FROM WEST.
CURRENT FORECAST TEMPERATURES LOOKS REASONABLE ATHMO. THICKNESS SCHEME
FULL SUN...AROUND 90...AC/AS...LOWER 80S. WILL ADJUST IF NECESSARY AFTER
A LOOK AT 11AM OBS.
ENJOY THE AFTERNOON.
.RAH...NONE.
RA
FXUS62 KMHX 231359 nc
AREA FORECAST DISCUSSION...UPDATED FOR POPS
NATIONAL WEATHER SERVICE CHARLESTON SC
1015 PM EDT MON AUG 23 1999
UPON FURTHER CONSIDERATION WL RUN WITH ISOLATED POPS ACROSS CWA.
RUC AND MESO ETA SHOWING DIFF SOLNS CONCERNING S/W ENERGY FOR
REMAINDER OF THE NIGHT. THE MESO KEEPS WEAK PVA OVR THE AREA THRU
THE NIGHT AND RUC INDICATES NVA. 88-D SHOWING SOME PRECIP OVR THE
ATLANTIC AFFECTING THE NEAR COAST AREAS. THIS IS REFLECTED IN THE
RUC SOLN AND WL LEAN TOWARDS THE RUC AND THE MESO PRECIP FIELDS ARE
NOT DOING WELL. WL DROP POPS ACROSS INLAND AREAS AND LOWER COASTAL
POPS TO ISOLATED.
CWF...WINDS HAVE BECOME SE OVR GA WATERS AND ESE OVR SC WATERS.
MAY SHIFT BETWEEN SE AND E FOR RST OF NGT ACRS SC CSTL WATERS... BUT
WL PROBLY RMN MOSTLY SE ACRS GA WATERS ALL NGT. WL CHG FCST SLIGHTLY
TO RFLCT THS TRND. WL CONT SCT POPS OVRNGT AS SERLY FLO CONTG TO
PUMP MSTR IN OFF ATLNTC. OTRW...RST OF FCST LUKS OK.
.CHS...
SC...NONE.
GA...NONE.
JCI/WOODWORTH
FXUS62 KCAE 240126 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
924 PM EDT MON AUG 23 1999
H5 DIFFLUENCE AND H85 WARM ADVECTION SUPPORTS CONTINUING POPS OVERNIGHT.
THE RUC CONFINED MOST OF THE WARM ADVECTION TO THE WEST PART THROUGH
09Z. PLAN TO KEEP 40 PERCENT POPS IN THE WEST BECAUSE OF THIS AND THE
LOW-LEVEL UPSLOPE FLOW. BELIEVE POPS CAN BE LOWERED TO SLIGHT CHANCE IN
THE EAST DUE TO LESS WARM ADVECTION AND THE LOSS OF SURFACE HEATING. NO
OTHER CHANGES PLANNED.
.CAE...NONE.
RJL
FXUS62 KCHS 240107 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
908 PM EDT MON AUG 23 1999
RUC AND MESO ETA SHOWING DIFF SOLNS CONCERNING S/W ENERGY FOR
REMAINDER OF THE NIGHT. THE MESO KEEPS WEAK PVA OVR THE AREA THRU
THE NIGHT AND RUC INDICATES NVA. 88-D SHOWING SOME PRECIP OVR THE
ATLANTIC AFFECTING THE NEAR COAST AREAS. THIS IS REFLECTED IN THE
RUC SOLN AND WL LEAN TOWARDS THE RUC AND THE MESO PRECIP FIELDS ARE
NOT DOING WELL. WL DROP POPS ACROSS INLAND AREAS AND LOWER COASTAL
POPS TO ISOLATED.
CWF...WINDS HAVE BECOME SE OVR GA WATERS AND ESE OVR SC WATERS.
MAY SHIFT BETWEEN SE AND E FOR RST OF NGT ACRS SC CSTL WATERS... BUT
WL PROBLY RMN MOSTLY SE ACRS GA WATERS ALL NGT. WL CHG FCST SLIGHTLY
TO RFLCT THS TRND. WL CONT SCT POPS OVRNGT AS SERLY FLO CONTG TO
PUMP MSTR IN OFF ATLNTC. OTRW...RST OF FCST LUKS OK.
.CHS...
SC...NONE.
GA...NONE.
JCI/WOODWORTH
FXUS62 KGSP 240038 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
837 PM EDT MON AUG 23 1999
SHORTWAVE CURRENTLY MOVING EAST ACROSS TN IN LINE WITH 21Z RUC AND
18Z ETA FORECASTS. VORT MAX IS FORECAST TO WEAKEN AS IT MOVES INTO
CWA LATER TONIGHT. ASSOCIATED JET MAX MOVES INTO NC
PIED...POSITIONING MUCH OF CWA IN FAVORED RIGHT ENTRANCE REGION.
MODELS DEPICT GOOD UPR LEVEL DIVERGENCE CENTERED OVER 850 MOIST
CONVERGENCE AND LOW-LEVEL UPSLOPE FLOW. WITH SEVERAL SOLID BANDS OF
SHRA/TSRA EITHER IN CWA OR TO OUR WEST ATTM...WILL UPDATE A LITTLE
EARLY AND INCREASE POPS TO LIKELY/CATEGORICAL. WILL ADD THAT PRECIP
WILL TAPER OFF AFTER MIDNIGHT...SINCE VORT MAX WEAKENS AND AIRMASS
STABILIZES. HOWEVER...SCATTERED SHOWERS WILL PROBABLY BE AROUND MOST
OF THE NIGHT AS WE MAINTAIN A MOIST SOUTH/SOUTHEASTLY FLOW. MAY
TWEAK TEMPS A LITTLE IN THE MTNS/NRN TIER OF NC FOOT AND PIED.
.GSP...NONE.
MOYER
FXUS62 KCHS 231916 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
228 PM EDT MON AUG 23 1999
GOOD AMOUNT OF CONVECTION ACROSS CWFA ATTM. LATEST RUC SHOWS UPPER
LEVEL JET MOVING THRU THIS EVENING ALONG WITH CONTINUED LOW LEVEL
SELY FLOW AND MOISTURE REMAINING HIGH. SHOULD SEE A GOOD AMOUNT OF
COVERAGE THIS EVENING.
12Z MDLS QUITE SIMILAR WITH WEATHER FEATURES THRU 48 HRS. STRONG
UPPER LOW DIVES INTO OH VLY THEN SLOWLY MOVES EWD. SOUTH TO
SOUTHEAST FLOW AT LOW LEVELS AND DEEP MOISTURE CONTINUE OVER THE
AREA THRU THE PERIOD. BEST FORCING MOVES TO OUR NORTH BUT GOOD OMEGA
DEVELOPS OVER OUR AREA IN RESPONSE TO UPPER JET MOVING AROUND THE
LOW. WEAK INSTABILITY TO CONTINUE AS WELL.
NGM ODD MAN OUT MOVING TROPICAL SYSTEM MUCH FARTHER NORTHWEST THAN
ETA OR AVN. MAIN EFFECTS SHOULD HOLD OFF UNTIL EXTENDED PERIOD.
FCST TEMPS PRETTY CLOSE AND GENERALLY EXCEPTED BUT WENT TOWARD
WARMER FWC NUMBERS AT AVL/GSP FOR TUESDAY.
AVL 63/77/64/78 5656
GSP 68/82/69/82 5656
GSP 67/82/68/82 5656
.GSP...NONE.
RWH
FXUS62 KCAE 231817 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1021 AM EDT MON AUG 23 1999
SOME CHANGES NEEDED TO GOING FCST. JET MAX ON 12Z H25 CHART SHOWN BY
LATEST RUC AND 03Z ETA TO MOVE ACROSS CWFA TODAY. 03Z ETA GENERATES
QUITE A BIT OF OMEGA ACROSS THE AREA THIS AFTERNOON AS WELL. ATMOS
ALREADY UNSTABLE AND CONVECTION ONGOING ATTM. THE RUC AND 03Z ETA
ALSO IN LINE WITH 00Z MDLS IN INCREASING SELY LOW LEVEL FLOW AND
MOISTURE. WILL ADD POPS TO ALL ZONES FOR THIS AFTERNOON. TEMPS IN
LINE AND LOOKING GOOD ATTM.
.GSP...NONE.
RWH
FXUS62 KCHS 231400 sc
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1019 AM CDT MON AUG 23 1999
COLD CORE UPPER LEVEL LOW MAIN ELEMENT THRU AFTN. STL LOCATES CENTER OF
CIRCULATION NR KETH...WITH A SSE DRIFT. ABR RAOB HAS 1C 700 HPA TMP...
WITH LTL COOLER MID LVL TMPS INDICATED BY STLT BIT FARTHER E. AREAS
EXTENT OF CU BUILDUP...AND DELINEATING POTENTIAL FOR SCATTERED AFTN
PRECIP ARE MAIN ISSUES TO WRESTLE.
12Z RUC LOOKS WELL INITIALIZED...AND FITS 15Z TRENDS WELL. FCST SNDGS
FOR MN AND ERN IA CWA DO EXHIBIT A VERY SMALL CAPE WITH WHAT APPEARS
TO BE REASONABLE LOW LEVEL TMP/MSTR PROFILES...BUT MAY BE A BIT ON THE
DRY SIDE...WITH MANY AREAS N AND E OF FSD WITH .5 INCH OR MORE WEEKEND
RAINFALL...WHICH WOULD ONLY MAKE LTL MORE FAVORABLE FOR SOME CONVECTIVE
DEVELOPMENT. WL UPDATE TO PUT IN SOME AFTN SHRA/TSRA IN SW MN INTO NW
IA...BUT THREAT WL LKLY DIMINISH BY MID AFTN AS COLDEST AIR ALFT SLIPS
BY AND LARGE SCALE SUBSIDENCE FORCING STRENGTHENS. MIXING DOWN OF NW
FLOW MOMENTUM WL ALSO MAKE FOR BRISK WINDS...AS ADVERTISED. TMPS NEED
BE TRIMMED A BIT AS WELL N AND E. WL BE SIGNIFICANLY MORE CLOUDINESS
E IN CWA VS W...SO WL TRY AND WORK THIS IN AS WELL.
.FSD...NONE
CHAPMAN
FXUS63 KABR 231515 sd
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
1040 PM CDT MON AUG 23 1999
EAST TO WEST SURFACE TROUGH CURRENTLY LOCATED OVER THE SOUTHERN TIER
COUNTIES ALONG A WICHITA FALLS...POST...HOBBS LINE. SHOWERS AND
THUNDERSTORMS ARE SHOWING SLIGHT WEAKENING AND CELLS ARE MOVING MORE
IN A WESTWARD DIRECTION DOWN THE BOUNDARY/TROUGH. RUC AND MESOETA
MODELS CONTINUE A SOUTHWESTWARD MOVEMENT BUT CURRENT RADAR TRENDS
ARE SHOWING REDEVELOPMENT NORTH OF THE TROUGH. WILL UPDATE THE
ZONES TO LOWER THE CHANCES FOR PRECIPITATION ACROSS THE NORTHERN
TIER COUNTIES AND LEAVE PRECIP CHANCES IN THE SOUTHERN SECTIONS FOR
NOW.
OUTFLOW FROM THUNDERSTORMS ARE WRECKING HAVOC ON THE WIND FIELD.
NOTHING MUCH TO HANG YOUR HAT ON FOR DIRECTION AND SPEED. KLBB
WSR-88D WIND PROFILE SHOWING OUTFLOW FROM THE WEST SOUTHWEST AT 4K
FEET...NORTHWEST AT 5K FEET AND NORTHEAST ABOVE 6K FEET. BELIEVE
AFTER THUNDERSTORMS WEAKEN THE WIND FIELD WILL RETURN TO A NORTHEAST
FLOW AND WILL LET THE CURRENT WINDS RIDE FOR NOW. REMAINDER OF
FORECAST ON TRACK.
.LBB...NONE.
SLW/16
FXUS64 KMAF 240337 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIDLAND TX
1035 PM CDT MON AUG 23 1999
QUITE A BUSY EVENING WITH CONVECTION ACROSS THE AREA...PERHAPS ONE
OF THE BUSIER EVENINGS SINCE LATE SPRING. STORMS THAT FORMED EARLIER
THIS EVENING ACROSS SE NM SENT OUT AN IMPRESSIVE OUTFLOW BOUNDARY...
WHICH IS PRESENTLY MAKING ITS WAY ACROSS THE PERMIAN BASIN AND THE
TRANS-PECOS REGION...EXTENDING APPROXIMATELY FROM SNYDER...TO
CRANE...TO NORTH OF FORT STOCKTON. AFTER SUNSET MOST OF THE STORMS
DIMINISHED CONSIDERABLY IN INTENSITY...AND ALL THAT REMAINS ARE
SCT THUNDERSTORMS BEHIND THE OUTFLOW BOUNDARY...WITH MOST OF THEM
REMAINING FAIRLY WEAK. LIGHTNING ACTIVITY WITH THE STORMS EARLIER
THIS EVENING WAS VERY IMPRESSIVE.
TROF/OLD FRONTAL BOUNDARY STILL SEEMS TO BE LAYING E-W ACROSS THE
SRN PLAINS...NORTH OF THE MAF CWA...AS PER SFC OBS AND CONVECTIVE
TRENDS. WILL NEED TO KEEP AN EYE ON THIS BOUNDARY DURING THE NEXT 24
HOURS. RUC DOES NOT MOVE THE BOUNDARY OUT OF THE AREA
SIGNIFICANTLY...AND IN FACT IT LOOKS AS IF THE RUC IS FORECASTING
THE BOUNDARY TO SAG FURTHER SWD INTO THE PERMIAN BASIN AND UPPER
TRANS-PECOS REGION BY TOMORROW AFTERNOON.
A LOOK AT THE IR AND WV IMAGERY SHOWS QUITE A MASS OF CLOUDS AND
MOISTURE PUSHING NWD AND NWWD OUT OF DEEP SOUTH TEXAS...REMNANTS OF
HURRICANE BRET. EARLIER FORECASTS AND MODEL GUIDANCE EXPECTED THIS
MOISTURE TO PUSH WESTWARD ACROSS NRN MEXICO...HOWEVER IT APPEARS THAT
AT LEAST PART OF THE SYSTEM'S REMNANTS WILL BE MOVING INTO MAF CWA.
IF THESE REMNANTS CONTINUE MOVING INTO THE AREA...THIS COULD
NEGATIVELY IMPACT THE PRESENT FORECAST FOR TOMORROW. MID SHIFT
WILL HAVE TO TAKE A CLOSER LOOK AT THIS SITUATION. NOT SURE IF
THE MOISTURE FLUX FROM BRET WILL MAKE IT FAR ENOUGH NORTH TO INTERACT
WITH THE TROF/STALLED BOUNDARY LAYING ACROSS THE AREA...BUT THIS IS A
POSSIBILITY THAT WILL HAVE TO BE EXAMINED.
FOR THE REST OF TONIGHT...WILL SEND OUT A ZONE UPDATE SHORTLY TO
REFLECT CURRENT TRENDS IN WINDS/TEMPS AND CONVECTIVE ACTIVITY. DJK
.MAF...
TX...NONE.
NM...NONE.
FXUS64 KFWD 240216 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
305 PM EDT MON AUG 23 1999
AWIPS VISIBLE SATELLITE SHOWED CLOUDS SPREADING EAST ACROSS THE FA
AS EXPECTED. SFC ANALYSIS PLACED HIGH CENTER AROUND PENNSYLVANIA
WITH LOW PRES IN MN WITH COLD FRONT TRAILING SOUTH. SFC OBS ACROSS
CWA PAINT A FAMILIAR S-SE UPSLOPE FLOW. KFCX 88D INDICATED SCT
SHOWERS AND THUNDERSTORMS ACROSS OUR SCOPE. MODIFIED RNK SOUNDING
CREATED AN LI OF MINUS 4 AND A CAPE AROUND 1500. 18Z LAPS DATA
INDICATED HIGHER CAPES FROM 1500 TO 2400 DEVELOPING ACROSS WESTERN
PORTION OF CWA. MSAS HAD DECENT MSTR CONVGC. AWIPS 5H COMBO SHOWED
STRONG CLOSED LOW OVER ND-MN DROPS SE INTO THE OHIO VALLEY BY 48
HOURS. SEVERAL WEAK SHORTWAVES DRIFT ACROSS FA BEFORE THE MAIN ONE
WITH INCREASING MOISTURE AND INSTABLILITY. AT THE SFC...LOW CENTER
IN MN WITH ITS ASSOCIATE COLD FRONT WILL MARCH SE. THE ETA AND RUC
APPEARED BEST WITH THE ONSET OF THE CONVECTION FOR OUR AREA THIS
AFTERNOON. THIS MORNING RUN OF THE MODELS TRYING TO MERGE TOGETHER
ON SIMILIAR SOLUTION. GENERAL TREND OF THE FORECAST CALLS FOR A
MOSTLY CLOUDY SKY WITH CHANCE OF SHOWERS AND THUNDERSTORMS. LOCALLY
HEAVY RAIN ARE POSSIBLE WITH SOME OF THE STORMS. TRAINING OF ECHOS
AND SLOW MOVEMENT OF THUNDERSTORMS COULD CREATE FLASH FLOODING PROBLEMS.
THE EXTENDED PERIOD COMPLICATED BY THE MOVEMENT OF THE TROPICAL
SYSTEM. ZONES WILL BE OUT AROUND 340 PM. HAVE A GUD NIGHT.
.RNK
VA...NONE.
NC...NONE.
WV...NONE.
KK
FXUS61 KAKQ 231444 va
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1015 AM EDT MON AUG 23 1999
DEVELOPMENT OF CONVECTION ACROSS SRN PDMT OF NC THIS MORNING IS
CONFIRMING THE 09Z RUC...WHICH CONTS TO BRING QPF UP INTO OUR SW
COUNTIES DURING THE DAY. THIS MAKES SENSE LOOKING AT 850 PLOT...WITH
HIGHER DWPTS WRAPPING UP AND AROUND THE BACKSIDE OF A WEAK HIGH
SITUATED OVER THE CENTRAL CAROLINAS. THIS FLOW IS ALSO
CONVERGENT...SO WILL ADD SOME POPS FOR THIS AFTN ACROSS THE NW MTNS
AND NRN FOOTHILLS OF NC. WILL HOLD OFF EVERYWHERE ELSE.
.RNK
VA...NONE.
NC...NONE.
WV...NONE.
va
WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
309 AM MDT TUE AUG 24 1999
WV IMAGERY SHOWED UPPER HIGH CIRCULATION OVER FOUR CORNERS REGION
SHUNTING MOISTURE NORTHWARD OVER WESTERN UTAH EARLY THIS MORNING WITH
THIN MID AND HIGH MOISTURE OVER THE CWFA. MEANWHILE...GOES SOUNDER
DATA INDICATED DEEPER MOISTURE BORDERING EASTERN UTAH ZONES AND ALSO
FOUND ALONG CO/NM BORDER AREA. ALL MODELS APPEAR WELL INITIALIZED
WITH THIS REGIME...THOUGH AVN RH FIELD VALUES HIGHER THAN EITHER THE
ETA OR THE NGM WHICH APPEARS TO BETTER FIT WITH LATEST IR AND WV
IMAGERY AS DESCRIBED ABOVE. 06Z RUC ALSO CLOSER TO AVN AND INDICATED
MOISTURE TO REMAIN A BIT HIGHER OVER SOUTHERN MOUNTAINS AND FOUR
CORNERS WHERE IR SHOWS MID CLOUDS SLOW TO DISSIPATE. OVER EASTERN
UTAH...APPEARS SOUTHWEST FLOW WILL ALLOW MOISTURE TO CREEP EASTWARD
DURING THE DAY. RUC ALSO SHOWED WEAK DISTURBANCE TO MOVE
NORTHEASTWARD ACROSS WESTERN UTAH DURING THE EARLY PART OF THE DAY...
PHASING WITH SHORTWAVE DRIFTING ACROSS THE NORTHWEST US THIS
AFTERNOON. LIFT ASSOCIATED WITH DISTURBANCE COMBINED WITH DIURNAL
WARMING SHOULD BRING AT LEAST A CHANCE OF THUNDERSTORMS TO NORTHEAST
UTAH IN ADDITION TO SOUTHEAST. COLORADO ZONES LIKELY TO REMAIN FAIRLY
DRY ACROSS THE NORTH AND CENTRAL PART OF THE STATE SO WILL LEAVE OUT
MENTION OF THUNDERSTORMS IN ALL BUT MOUNTAIN AND SOUTHERN ZONES
TODAY. NORTHWESTERN US SHORTWAVE TO BRUSH NORTHERN PORTION OF THE
CWFA THIS EVENING WHILE MOISTURE CONTINUES TO FILL IN...SO WILL BRING
IN SLIGHT CHANCE OF THUNDERSTORMS TO NORTHWEST ALONG WITH CENTRAL
VALLEYS AS WELL. EXPECT CONVECTION TO END IN THE EVENING WITH SOME
CLEARING AS DISTURBANCE MOVES EAST. MAIN MOISTURE BAND WILL ALIGN
ITSELF ACROSS THE FORECAST AREA WEDNESDAY...SO EXPECT AFTERNOON
THUNDERSTORMS TO BE A BIT MORE WIDESPREAD. TEMPERATURES NOT LIKELY TO
CHANGE SIGNIFICANTLY FROM YESTERDAYS SO WILL NOT DEVIATE MUCH FROM
MOS GUIDANCE.
WESTERN COLORADO AND EASTERN UTAH EMERGENCY MANAGERS SHOULD MAINTAIN
A NORMAL LEVEL OF WEATHER AWARENESS TODAY.
.GJT...NONE.
FXUS65 KBOU 240901 co
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
306 AM EDT TUE AUG 24 1999
FORECAST CHALLENGE - POPS
CURRENTLY - DISSIPATING CONVECTION FROM MCS IS LINGERING OVER NW CWA
WHILE MID/HIGH CLOUDS FROM THIS MCS DRIFT SE OVER CWA. WATER VAPOR
IMAGES SHOW A MINOR UPPER SHORTWAVE TROUGH OVER S AL ASSOCIATED WITH
THIS CONVECTION. A STRONG VORT MAX FARTHER UPSTREAM OVER UPPER MS
VALLEY IS DIVING SE.
TODAY - RUC PROGS MINOR SHORTWAVE TROUGH TO PASS E OF CWA BY THIS
AFTERNOON...PUTTING WRN CWA IN WEAK SUBSIDENCE BEHIND THIS FEATURE.
DEEP LAYER Q-FORCING ASSOCIATED WITH STRONG VORT MAX TO STAY NW OF
CWA NEAR PRE-FRONTAL SURFACE TROUGH. MEAN FLOW BELOW 700 MB PROGGED
TO BE RATHER LIGHT THIS AFTERNOON...SUGGESTING HIGHEST POPS
ASSOCIATED WITH SEA BREEZE SHOULD STAY AROUND TOPOGRAPHICALLY
FAVORED AREAS LIKE AQQ...AS WAS SEEN YESTERDAY. HIGHER POPS
JUSTIFIED OVER SE AL CLOSE TO PRE-FRONTAL TROUGH. MODELS AGREE ON
GENERATING GOOD PRECIPITATION OVER GA AHEAD OF APPROACHING UPPER
VORT MAX...SO WILL GO WITH GOOD CHANCE NRN GA ZONES.
TONIGHT - WILL CONTINUE POPS FOR NRN ZONES IN CASE MCS TRIES TO MOVE
SE INTO CWA AS WAS SEEN MONDAY NIGHT. AGREE WITH LATEST SPC SWODY1
SUGGESTING THAT MCS SHOULD BE ABLE TO MAKE IT AT LEAST AS FAR S AS
CENTRAL GA/AL.
WEDNESDAY - VORT MAX BEGINS TO CUT OFF OVER OH VALLEY...RESULTING IN
BROAD UPPER CYCLONIC FLOW OVER OUR CWA. SURFACE FRONT PROGGED TO STALL
JUST NW OF CWA BY THIS TIME AND ATMOSPHERIC MOISTURE EXPECTED TO
INCREASE. WILL THEREFORE GO WITH HIGHER POPS THAN TODAY SINCE
ADDITIONAL LIFT AND MOISTURE WILL BE IN PLACE.
MARINE - NO HIGHLIGHTS EXPECTED.
EXTENDED - CURRENT FORECASTS LOOK FINE.
WORK ZONES AND CCF ALREADY OUT. WORK CWF OUT BY 0730Z. THANKS TO
MOB FOR COORDINATION THIS MORNING. INPUT IS ALWAYS WELCOME.
TLH 093/072 093/072 4353
PFN 090/075 089/076 5353
DHN 092/073 093/071 4353
ABY 093/072 092/072 5453
VLD 093/071 092/072 4353
TJT
FXUS62 KMLB 240655 fl
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
1030 AM EDT MON AUG 23 1999
FORECAST CONCERNS THIS AFTN CENTER AROUND MAX TEMPS AND CLOUD COVER.
12Z SFC ANALYSIS SHOWED MESOLOW OVER SW MO WITH MESOHIGH IN SCNTL MO IN
ASSOCIATION WITH MCS. HIGH BASED CLOUDINESS OBSCURING SUNSHINE ACROSS
ERN KY ATTM BUT MORE SUN BREAKING OUT WEST OF I-75. THIS IN AREA OF NVA
AT 5H. 12Z BNA SOUNDING SHOWING LOTS OF DRY AIR IN THE LOWER LEVELS
WITH MOISTURE AT 600 TO 500 MB LAYER. 12Z RUC SHOWS LOW LVL MOISTURE
INCREASING OVER ERN KY THIS AFTN BUT THINK IT IS TOO FAST. LAST NIGHTS
MESOETA SEEMED TO BE HANDLING THINGS SLIGHTLY BETTER. IT WAS PRINTING
LIGHT QPF OVER ERN TN TODAY AND KJKL 88D IS SHOWING LIGHT ECHOES MOVING
EAST THROUGH THE CUMBERLAND PLATEAU ATTM.
CURULE SHOWING SOME DEVELOPMENT IN THE MTNS THIS AFTN AND WITH SOME
HIGH LEVEL MOISTURE AROUND FROM TIME TO TIME WILL KEEP PARTLY SUNNY
WORDING GOING. TEMPS AT BELOW THE 00Z FWC MOS TREND FOR NOW WITH THE
EXCEPTION OF LEX. WILL LOOK AT 15Z TEMPS AND MAKE A DECISION ON WHETHER
TO UPDATE ZONES OR NOT TO LOWER HIGHS.
.JKL...NONE.
WHP
ky
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
230 PM CDT MON AUG 23 1999
MODELS ARE STILL POINTING TO A 30 PERCENT-TYPE RAIN EVENT THAT
EXTENDS ALONG THE ENTIRE I20 CORRIDOR. NGM FWC NUMBERS ARE 30 PCT...
AND ETA AND NGM FOUS GIVES QPF OVERNIGHT AT SHV. MAIN FOCUS IS
TONIGHT AND TUESDAY WITH PASSAGE OF VORTICITY AXIS AND SURFACE
BOUNDARY. SFC DEWPOINTS HAVE MOISTENED UP ACROSS MOST OF CWA EXCEPT
NEAR LUFKIN WHERE IT ALREADY WAS STICKY. TEMPS ALL MORNING HAVE BEEN
HIGHER THAN 24 HOURS AGO. SHOWN THAT RUC POINTS TO DECENT MOISTURE
FLUX CONVERGENCE FROM FORT SMITH TO WICHITA FALLS THIS EVENING. THIS
IS INTERESTING IN THAT MY MAIN POPS CONCERN TONIGHT IS THE TEXAS
PORTION OF THE I20 CORRIDOR...WHERE I HAVE A BIT OF A HARD TIME
JUSTIFYING CHANCE POPS GIVEN BY THE NGM. MAYBE THE RUC IS ON TO
SOMETHING. EVEN SO...CAN THIS SYSTEM IF IT DEVELOPS MAKE IT FAR
ENOUGH SOUTH OVERNIGHT. I THINK I WILL GO LOWER THAN GUIDANCE AND
SAY 20 PERCENT FOR GGG/TYR TONIGHT.
20 PCT POPS THIS EVENING NEAR LFK IN CASE OF OUTFLOW BOUNDARIES FROM
EARLIER CONVECTION TO THE SW. BUT A BREATHING-IN PERIOD OVERNIGHT FROM
BRET WILL NOT LET CONVECTION LAST LONG THERE THIS EVENING.
POSITION OF SFC TROF IS A CONSIDERATION TOMORROW FOR UPPING MAX
TEMPS IF IT WEREN/T FOR THE POSBL CLOUDS AND SHOWERS. WILL GO HIGHER
THAN GUIDANCE SOUTHERN TIER TUESDAY...AND OVER SRN AR/SE OK. IT IS
ALONG AND AHEAD OF TROF/FRONT THAT PERHAPS ANOTHER BATHC OF TSTMS
WILL FIRE...GIVEN THE SLGT RISK FOR FAR NRN LA AND SRN AR ON THE
SECOND DAY OUTLOOK. GIVEN THE MARGINALITY OF THIS...WILL NOT MENTION
A /SOME POSSIBLY SEVERE/ WORDING. BUT POPS FOR MLU AREA WILL BE THE
CONSISTENTLY HIGHEST IN MY PRODUCT.
BY 48 HOURS WE WILL HAVE AN UPPER TROF TO NE AND UPPER RIDGE TO NW.
N/NW FLOW ALOFT ALWAYS HAS POTENTIAL TO SURPRISE US...BUT THERE IS
ALSO A NORTHERLY FLOW AT SURFACE. THIS CAUSED THE MRF TO DROP POPS
LOW ENOUGH TO NIL THEM OUT FOR WED AND THURSDAY EXCEPT DOWN SOUTH
WEDNESDAY. SO SUGGEST EVENING SHIFT ADD THURSDAY TO THE DRY DAYS IN
THE EXTENDED AND THEN REINTRO SLIGHT CHANCES FOR SATURDAY. 17
PRELIM GUESSES...
SHV 73/96/72/95 2320
MLU 73/96/70/95 3330
TXK 71/97/69/95 3320
TYR 72/96/70/96 2220
LFK 74/97/73/96 2322
.SHV...NONE.
FXUS64 KLIX 231917 la
FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
100 AM CDT TUE AUG 24 1999
ISOLATED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OVER THE PAST HOUR
AND THE 03Z RUC INDICATES INCREASING MOISTURE AND LOW LEVEL
CONVERGENCE ACROSS MAINLY CENTRAL MS THROUGH 700AM. WILL UPDATE THE
ZONES TO MOSTLY CLOUDY AND KEEP LOW POPS IN THE FIRST PERIOD. TEMPS
LOOK ON TRACK FOR NOW WITH WINDS MOSTLY SOUTH.
JAN...
MS...NONE.
LA...NONE.
AR...NONE.
FXUS74 KJAN 240337 ms
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
250 AM MDT TUE AUG 24 1999
ETA INITIATLZD SVRL WVS AS SEEN ON WAT/VAP THIS MRNG. FIRST WV EXTS
NE OF FA EARLY TOD WITH WV OVR SE ORE MOVG ACRS ERN ID AND INTO SW
MT BY MIDDAY. TAIL BRUSHING FAR W WY BY MIDDAY THEN E OF DVD BY
AFTN. TRAILG WV TO REACH THE NW CRNR THIS EVG AND ACRS THE N LTR
TNGHT. UPR FLOW STARTS VEERG TO THE WEST BY THIS AFTN WITH A SHT/WV
RDG MOVG IN BY WED IN LGHT WESTRLY FLOW ALF WITH LESSER HGHTS THAN
TODAY. CRRNT FCST ON TRAK WITH TSTMS HOLDG OFF E OF DVD UNTIL THIS
EVG (XCPT IN THE XTRM N) WITH ONLY ISOLD. IN THE W THOUGH WILL INCRS
CVRG FOR THIS AFTN/EVG TO SCT...ESPLY NW. MDL QPF BRINGS LGHT AMTS TO
THE NW CRNT THIS AFTN/EVG WITH NO ACUMM ELSWR. RUC AND MESO-ETA SNDGS
FCST FOR THIS AFTN HAVE DRY MICRO-BURST POTENTIALS IN THE FAR WEST
LESS THAN 30KTS. H8 TMPS FCST TO COOL A LTL IN THE NW TODAY WITH TMPS
OTHRWS FCST TO BE ABT THE SAME FM MON AFTN/S INITILIZATION THRU WED
AFTN. IN EXTND NEW AVN/MRF KEEPS RIDGE THUR WITH MAINLY DRY CONDS ON
TRAK WITH CRRT FCST. RWM
RIW...NONE.
FXUS65 KCYS 240811 wy
WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
309 AM MDT TUE AUG 24 1999
WV IMAGERY SHOWED UPPER HIGH CIRCULATION OVER FOUR CORNERS REGION
SHUNTING MOISTURE NORTHWARD OVER WESTERN UTAH EARLY THIS MORNING WITH
THIN MID AND HIGH MOISTURE OVER THE CWFA. MEANWHILE...GOES SOUNDER
DATA INDICATED DEEPER MOISTURE BORDERING EASTERN UTAH ZONES AND ALSO
FOUND ALONG CO/NM BORDER AREA. ALL MODELS APPEAR WELL INITIALIZED
WITH THIS REGIME...THOUGH AVN RH FIELD VALUES HIGHER THAN EITHER THE
ETA OR THE NGM WHICH APPEARS TO BETTER FIT WITH LATEST IR AND WV
IMAGERY AS DESCRIBED ABOVE. 06Z RUC ALSO CLOSER TO AVN AND INDICATED
MOISTURE TO REMAIN A BIT HIGHER OVER SOUTHERN MOUNTAINS AND FOUR
CORNERS WHERE IR SHOWS MID CLOUDS SLOW TO DISSIPATE. OVER EASTERN
UTAH...APPEARS SOUTHWEST FLOW WILL ALLOW MOISTURE TO CREEP EASTWARD
DURING THE DAY. RUC ALSO SHOWED WEAK DISTURBANCE TO MOVE
NORTHEASTWARD ACROSS WESTERN UTAH DURING THE EARLY PART OF THE DAY...
PHASING WITH SHORTWAVE DRIFTING ACROSS THE NORTHWEST US THIS
AFTERNOON. LIFT ASSOCIATED WITH DISTURBANCE COMBINED WITH DIURNAL
WARMING SHOULD BRING AT LEAST A CHANCE OF THUNDERSTORMS TO NORTHEAST
UTAH IN ADDITION TO SOUTHEAST. COLORADO ZONES LIKELY TO REMAIN FAIRLY
DRY ACROSS THE NORTH AND CENTRAL PART OF THE STATE SO WILL LEAVE OUT
MENTION OF THUNDERSTORMS IN ALL BUT MOUNTAIN AND SOUTHERN ZONES
TODAY. NORTHWESTERN US SHORTWAVE TO BRUSH NORTHERN PORTION OF THE
CWFA THIS EVENING WHILE MOISTURE CONTINUES TO FILL IN...SO WILL BRING
IN SLIGHT CHANCE OF THUNDERSTORMS TO NORTHWEST ALONG WITH CENTRAL
VALLEYS AS WELL. EXPECT CONVECTION TO END IN THE EVENING WITH SOME
CLEARING AS DISTURBANCE MOVES EAST. MAIN MOISTURE BAND WILL ALIGN
ITSELF ACROSS THE FORECAST AREA WEDNESDAY...SO EXPECT AFTERNOON
THUNDERSTORMS TO BE A BIT MORE WIDESPREAD. TEMPERATURES NOT LIKELY TO
CHANGE SIGNIFICANTLY FROM YESTERDAYS SO WILL NOT DEVIATE MUCH FROM
MOS GUIDANCE.
WESTERN COLORADO AND EASTERN UTAH EMERGENCY MANAGERS SHOULD MAINTAIN
A NORMAL LEVEL OF WEATHER AWARENESS TODAY.
.GJT...NONE.
FXUS65 KBOU 240901 co
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1046 AM EDT TUE AUG 24 1999
IN THE SHORT TERM...SEA BREEZE CONVECTION EXPECTED THIS AFTERNOON
WITH OVERALL S-SE WIND FLOW. MM5 HAS THIS & WITH A BIT LESS
CONVECTION INDICATED. MAX AREA SHOULD AGAIN BE MAINLY WEST OF
TLH...SIMILAR TO MON. 12Z TLH SOUNDING HAD PRECIP WATER VALUE A BIT
LOWER THAN MON...BUT REALLY WOULD NOT EXPECT MUCH LOWER AMOUNT OF
CONVECTION AS AVAILABLE MOISTURE STILL HIGH. LI REMAINS -4 TO -6 &
CAPE LESS THAN 2000 WHEN MODIFIED FOR AFTERNOON. CONVECTION WILL
LAST UNTIL AFTER SUNSET. WILL ALSO HAVE TO WATCH REMNANTS OF MCS
NOW OVER NORTHERN AL. RUC DOES WEAKEN IT & TAKE MUCH OF ENERGY TO
E-NE OF CWA...BUT OUT-FLOW BOUNDARIES COULD SET-UP SOME CONVECTION
IN CENTRAL TO SRN AL & GA THIS AFTERNOON TO EVENING. CURRENT POPS &
TEMP FCST LOOK GOOD. WILL UPDATE FCST FOR COSMETIC CHANGES ONLY.
MCT
FXUS62 KTBW 241432 fl
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1040 AM EDT TUE AUG 24 1999
12Z RAOBS/SFC OBS SHOW NRLY VERTICAL CYC OVR IL MOVG SLOWLY ESEWD
PER WV LOOP. NRN GRT LKS IN UPR/SFC RDG AXIS BTWN THIS CUTOFF LO AND
MAIN ZONAL FLOW ACRS CNTRL CAN. LATEST SFC OBS/VIS SAT INDICATE
PTCHY LO CLD/FOG OVR CWA WITH SFC DWPTS GENERALLY ARND 62. LO CLD IN
PROCESS OF BURNING OFF WITH LTL IN THE WAY OF HIER CLD IN UPR RDG
AXIS TO BLOCK STRG AUGUST INSOLATION. 12Z GRB/APX SDNGS SHOW SHALLOW
NR SFC MSTR BLO RADIATION INVRN AND DRIER AIR WITH LAPSE RATE NR
MOIST ADIABATIC. 12Z INL SDNG IS SIMILAR IN LO LVLS BUT WITH MUCH
STRGR MID LVL SUBSIDENCE INVRN FARTHER N OF CUTOFF LO.
MAIN FCST CONCERNS TDAY ARE CLD TRENDS/TEMPS AND POTENTIAL FOR
CNVCTN. 09Z RUC INDICATES H5 HGTS/SFC RDG WL BLD OVR CWA/LK SUP TDAY
AS STORM TO S SINKS ESEWD. SINCE HIER CLD ASSOCIATED WITH CYC SWIRL
IN IL WL REMAIN TO S TDAY...XPCT PTCHY FOG/ST TO BURN OFF QUICKLY
REMAINDER OF MRNG WITH LOTS OF SUN. ALTHOUGH SOME CU WL FORM WITH
RELATIVELY HI NR SFC DWPTS...DRIER AIR NOTED ABV SHALLOW MSTR LYR ON
MRNG RAOBS AND INCRSG SUBSIDENCE UNDER BLDG RDG WL RESTRICT ANY DEEP
CNVCTN ESPECIALLY WITH LACK OF SGNFT BNDRY MORE THAN WEAK LK BREEZE
CNVGC.
WL BUMP UP MAX TEMPS FCST A TAD MOST ZNS GIVEN XPCTD SUNSHINE.
.MQT...NONE.
KC
FXUS63 KMQT 240806 mi
FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
335 AM CDT TUE AUG 24 1999
ISOLATED SHOWERS AND THUNDERSTORMS HAVE PERSISTED OVERNIGHT IN LIGHT
SLY WIND FLOW THAT WAS BRINGING 1.6-1.9" PRECIPITABLE WATER AIRMASS
BACK NWD ACROSS LOWER MS VALLEY. HIGH LEVEL OUTFLOW MOISTURE FROM
BRET LEFTOVERS IN TX BIG BEND ALSO HELPING TO SET THE STAGE FOR SOME
DECENT RAINFALL COVERAGE ACROSS THE FORECAST AREA THROUGH EARLY
TONIGHT. ONGOING BAND OF THUNDERSTORMS FROM KMEM TO KLIT SINKING
SEWD IN AXIS OF DECENT 850MB MOISTURE CONVERGENCE WHICH IS
MAINTAINED BY 06Z RUC THROUGH MIDDAY. THESE CLOUDS WILL KEEP
TEMPERATURES DOWN A BIT ACROSS THE DELTA REGION AS NEW CONVECTION
FIRES DURING THE MORNING.
A CLOSED MID-UPPER LEVEL LOW CENTER WILL DROP INTO KY FROM CENTRAL
IL TODAY. THIS LOW SHOULD CUTOFF NR TN/KY BORDER WEDNESDAY AND BEGIN
FILLING BY THE WEEKEND. THE ASSOCIATED SURFACE FRONT FROM SERN MO
ACROSS THE OZARKS INTO THE RED RIVER VALLEY WILL PUSH TO AROUND
HIGHWAY 82 BY THIS EVENING. THIS TIMING WILL BE ADVANTAGEOUS FOR THE
NEEDED RAINS IN NRN PORTIONS TODAY...CENTRAL PORTIONS THIS EVENING
AND S SECTIONS ON WEDNESDAY AS THE BOUNDARY STALLS.
THE COMBINATION OF 3000-4000 CAPES AND STORM RELATIVE HELICITIES IN
THE 75-125 RANGE ALONG THE FRONT SHOULD PROVIDE ENOUGH ORGANIZATION
FOR A FEW WIND DAMAGE REPORTS. A MODERATE BAND OF OMEGA WILL ALSO
HELP THE FORMATION OF SOME WEAK SURFACE WAVES RIDING NEWD ALONG THE
BOUNDARY. UNTIL WE SEE WHERE THE BEST DESTABILIZATION OCCURS...IT
WILL BE DIFFICULT TO PINPOINT A MENTION OF SEVERE SO WILL WORD IN
GUSTY NEAR STORMS FOR NOW.
SOME DRYING OUT EXPECTED N OF INTERSTATE TWENTY WEDNESDAY EVENING
BUT THE STALLED UPPER TROF AXIS LINGERS ACROSS THE AREA INTO THE
WEEKEND TO KEEP SOME DIURNAL CHANCES FOR ADDITIONAL PRECIPITATION.
QPF DISCUSSION: INSTABILITY WILL INCREASE ACROSS THE REGION WITH
COLD FRONT COMING IN FROM THE NORTHWEST THIS AFTERNOON. WIDELY
SCATTERED SHOWERS OR THUNDERSTORMS SHOULD PERSIST THROUGH THE MORNING
OVER MAINLY N HALF AS THE FRONT APPROACHES. THUNDERSTORMS WILL
INCREASE IN COVERAGE FROM NORTH TO SOUTH BY THIS AFTERNOON THROUGH
THIS EVENING. THE BEST CONVECTIVE ACTION SHOULD BE THIS EVENING IN
THE CENTRAL SECTIONS. SO WITH THIS IN MIND WILL PUT IN AN AVERAGE .75
INCH QPF FOR THE CENTRAL... .50 INCH QPF FOR THE NORTH AND .50 INCH
FOR THE SOUTH THROUGH 24 HOURS...GENERALLY SIMILAR TO NCEP.
.JAN...
MS...NONE.
LA...NONE.
AR...NONE.
FXUS74 KJAN 240607 ms
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
930 AM EDT TUE AUG 24 1999
WATER VAPOR IMAGERY CLEARLY SHOWS THE UPPER LO WOBBLING ACROSS IL
THIS MORNING. S/WVS CIRCULATING AROUND THE LO ARE HARDER TO PICK OUT
BUT APPEARS ONE IS BEGINNING ITS TREK ACROSS THE CAROLINAS NOW. BOTH
THE LATEST RUC & MESO-ETA RUNS WEAKEN THIS VORT FURTHER. BUT WHEN
COMBINED W/ A SOMEWHAT UNSTABLE (MODIFIED 12Z SOUNDINGS GIVE LIS -2
TO -5) & MOIST (PWS 1.2-1.9) AIRMASS...IT SHOULD PROVIDE ENOUGH LIFT
TO PRODUCE SCT TRW W/ MAX HEATING. ACTIVITY OFF THE CAPE FEAR CST IS
ADVECTING IN ON LO-LVL ONSHORE FLOW SO WILL RAISE POPS ALONG THE CST TO
CHC AREA. GOING COASTAL TEMPS AGREE W/ LATEST LAMP GUIDANCE & WILL
CONTINUE BUT WILL JACK UP TEMPS CLOSER TO LAMP INLAND WHERE MORE SUN
THIS MORNING WILL ALLOW A LITTLE MORE HEATING.
CWF: HI PRES OFF THE NJ CST ALLOWING FOR A NERLY OR ERLY FLOW THIS
MORNING W/ CSTL MTRS/OMR/BOYDAT SHOWING MAINLY NE WINDS. WILL DECIDE
ON INITIAL DIRECTION BASED ON OBS AROUND 15Z. NO OTHER BIG CHANGES
PLANNED.
.ILM...NONE.
LGE
FXUS62 KRAH 240650 nc
FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
1020 AM CDT TUE AUG 24 1999
FORECAST CHALLENGE FOR UPDATE CONTINUES TO BE TEMPS AND CLD TRENDS.
SFC HIGH SITUATED OVR FA ATTM. WK SHORT WAVE FROM WV LOOP OVR
WESTERN NORTH DAKOTA WILL SHIFT SLOWLY EAST OVR RIDGE TODAY. FROM
RUC TIME SECTIONS AND 12Z UA ANALYSIS LITTLE IN THE WAY OF MOIST
EXCEPT FOR LOWEST 150MB WITH THE REMAINDER OF THE COLUMN QUITE DRY.
SO OTHER THAN SCT CU DEVELOPMENT RESULTING FROM CU RULES SHOULD SEE
PLENTY OF SOLAR AS LITTLE IN THE WAY OF UPSTREAM CLOUD COVER
ASSOCIATED WITH S/W. THIS HANDLED WELL BY ONGOING FCST AND WITH TEMPS
ABOUT AS EXPECTED ONLY CHANGES ATTM WILL BE LIFTING MENTION OF AM
BR.
.FGF...NONE.
VOELKER
FXUS63 KBIS 240821 nd
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1011 AM EDT TUE AUG 24 1999
PIECE OF ENERGY EJECTED FROM WELL DEFINED UPPER LOW CURRENTLY CROSSING
CWFA...DRIVING SIZABLE BATCH OF RAIN & EMBEDDED CONVECTION. 09Z RUC
& 03Z ETA SUPPORT EARLIER MODEL TRENDS OF SHEARING THIS FEATURE &
IT'S ASSOCIATED OMEGA BULLSEYE EASTWARD THRU THIS AFTERNOON. IN THE
LARGER PICTURE...PERSISTENT MOIST SSE LLVL FLOW WILL CONTINUE TO
COMBINE WITH MODERATE LARGE SCALE FORCING & UPPER DIFFLUENCE TO
WARRANT A CONTINUATION OF HIGH POPS. CURRENT 88D TRENDS INDICATE
AT LEAST LIKELY COVERAGE REDEVELOPING IN WAKE OF S/WV...ACROSS
NE GA. IN ADDITION...LATER THIS AFTERNOON...WITH APPROACH OF
MAIN UPPER LOW...Q-VECT FORCING & LLVL FLOW CONVERGENCE INCREASES
...ACROSS THE MTNS. STILL PLENTY OF MOISTURE AVAILABLE TO WRING
OUT THIS AFTERNOON WITH 12Z GSO SNDG PW NEARING 150% OF NORM.
CONVECTIVE PCPN TOTALS SINCE LATE AFTERNOON YSTDY HAS PRODUCED
SCATTERED 2-3 INCH RAINFALL TOTALS ACRS WESTERN TWO-THIRDS OF
THE CWFA. LOCALIZED FLDG THREAT IS EXPECTED TO REMAIN APPARENT
THIS AFTERNOON & EVENING...BUT UNABLE TO NARROW DOWN AN AREA
WHICH HAD ENOUGH WIDESPREAD RNFL THIS AM IN CONJUNCTION WITH
THE UNCERTAINTY OF WHERE THE NEXT COMPLEX OF CONVECTIVE RNFL
WILL DEVELOP TO WARRANT PLACEMENT OF FFA AT THIS TIME.
.GSP...NONE.
CSH
FXUS62 KCHS 241403 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
317 AM EDT TUE AUG 24 1999
SFC ANALYSIS INDICATING RIDGING OVR AREA AS S/W APCHS. MODELS NOT IN
GOOD AGREEMENT WITH TIMING OF S/WS. NGM HANGS VORT MAX OVR THE CWA AS
ETA EJECTS IT OUT OVR ILM. 03Z RUC IN LINE WITH NGM IN TRYING TO KEEP
S/W OVRHEAD TDY...ALSO TRIES TO INDICATE A WDGE TYPE PATTERN...KEEPING
DRY AIR IN OVR THE MIDLANDS. AVN KICKS LEAD S/W EWD BUT HANGS SECONDARY
S/W OVR THE CWA THRU TNGT. RUC NOT INITIALIZING SECONDARY S/W VERY WELL
BUT TSRA CLUSTER OVR SRN GA INDICATIVE OF SOMETHING. NOT SURE HOW TO
HANDLE THIS SRN S/W...CURRENT MVMT IS E. SHRA DEV IN ASSOC WITH LEAD S/W
OVR NRN GA/WRN NC IS DYING OUT OVR SC BUT WILL PROBABLY HOLD TOGETHER AS
S/W MOVES THRU TDY. RUC PRACTICALLY CLEARS US OUT TDY AS MESO ETA
REMAINS VERY MOIST AND UNSTABLE. WILL GO WITH PROGRESSIVE ETA AND DRY
THINGS UP A BIT. WILL CUT BACK POPS OVR CWA AND INCR OVR PIEDMONT AS
MOST OF THE PRECIP HAS REMAINED W OF THE AREA. ALSO NGM IS HOLDING
PRECIP BACK TO THE W OVR CSRA AND ALONG THE QUASI-STATIONARY FRONT.
LOOKS LIKE OHIO VLY FRONT WILL TAKE ITS SWEET TIME GETTING HERE BUT WILL
KEEP AN EYE FOR WED AND THURS. WILL WAIT TO SEE WHAT HAPPENS TO DENNIS
AS THE WEEK GOES ON. WILL GO WITH GUIDANCE FOR TEMPS BUT NOT QUITE AS
WARM AS FWC.
PRELIM CCF
CAE TB 089/072/088 343
AGS TB 089/070/091 533
.CAE...NONE.
JDB
FXUS62 KGSP 240523 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1055 AM EDT TUE AUG 24 1999
UPPER LOW CONTINUES TO SPINS ACROSS CENTRAL IL WITH CONVECTION
BUILDING ACROSS SOUTHERN IN. CURRENT FORECAST ON TARGET AND NO
UPDATES PLANNED AT THIS TIME. MESO-ETA HAS A JET MAX MOVING ACROSS
TENNESSEE THIS AFTERNOON AND EVENING... WITH ASSOCIATED UPPER
DIVERGENCE. AS THE 50H LOW SPINS INTO THE OHIO VALLEY THERE WILL BE
GOOD 50H PVA... 50H TEMPS DROP TO -8 OR -9 C... AND 50H WINDS
INCREASE TO 30 TO 35 KTS. THE MESO-ETA ALSO INDICATES GOOD QVECTOR
CONVERGENCE WITH THIS UPPER LOW. THE DYNAMICS APPEAR TO BE IN PLACE
FOR A CHANCE OF SEVERE WEATHER.
MODIFIED BNA 12Z SOUNDING INDICATES CAPES AROUND 2500 J/KG. 12Z RUC
SOUNDINGS ALSO INDICATE BETWEEN 2000 TO 2700 J/KG THIS AFTERNOON
AND EVENING ACROSS THE CWA. THE MAIN QUESTION WILL BE THE AMOUNT OF
SUNSHINE... AS LOW CLOUDS WERE ACROSS MUCH OF THE CWA AND AN
ADVANCING ANVIL ACROSS SOUTHERN TN. THINK THAT THE LOW CLOUDS WILL
SLOWLY LIFT INTO BKN CU THIS AFTERNOON... AND THE CI FROM THE ANVIL
IN THE LAST FEW IMAGES MAY BE STARTING TO BREAK FROM THE CONVECTION
ACROSS MS... AND THEN MAY THIN. THE MAIN THING THAT THE ANVIL WILL
DO WILL BE TO CREATE ANOTHER BOUNDARY ACROSS MIDDLE TN... AS
NORTHERN MIDDLE TN HAS RECEIVED NEARLY FULL SUN THIS MORNING. THINK
THAT THE CONVECTION WILL START IN MIDDLE TN... CLOSER TO THE LOW
LEVEL CONVERGENCE AND MOISTURE CONVERGENCE AND ALSO WHERE THE BEST
INSTABILITY WILL BE... AND THEN MOVE INTO EAST TN. THE MAIN THREAT
WILL BE WINDS AS BNA SOUNDING IS FAIRLY DRY ABOVE 600 MB...AND WATER
VAPOR INDICATED A GOOD MID LEVEL DRY PUNCH COMING INTO TN. WILL ALSO
KEEP THE MENTION OF HEAVY RAIN... AS THE 80H THETA-E RIDGE REMAINS
OVER EAST TN THIS AFTERNOON AND MOST OF THE NIGHT... AND THE PRECIP
WATERS WILL BE AROUND 1.5 INCHES.
.MRX...NONE.
RBP
FXUS64 KOHX 241441 tn
WAKEFIELD FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1014 AM EDT TUE AUG 24 1999
DSCN: LTST SATL/RDR IMAGERY AGREES FAIRLY WELL WITH 12Z RUC...AS S/W
VORT MAX OVR CHES BAY LIFTS SLOWLY NEWD TODAY...AND AREA OF NVA OVR
S CNTRL VA THIS MORNG WEAKENS...WL UPDATE ZONES TO REFLECT MORE OF P
SUNNY FCST...WITH MAX TEMPS WELL INTO THE 80S. SCTD SHWRS DVLPG IN
WRN CWA THIS AFTN...AND PSBLY REDVLPG FAR NERN CWA IN VCNTY OF S/W.
CWF...MINOR ADJUSTMENTS MADE.
.AKQ...NONE.
HESS
FXUS61 KAKQ 240744 COR va
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
1020 AM CDT TUE AUG 24 1999
SATELLITE IMAGERY AND UPPER AIR ANALYSIS SHOWING VERTICALLY STACKED
SYSTEM OVER NORTHERN ILLINOIS THIS MORNING... SLOWLY MOVING TO THE
SOUTHEAST. ACROSS THE FORECAST AREA... LOW CLOUDS AND FOG CONTINUE
TO BE THE CONCERN IN THE SHORT TERM.
12Z LAPS SOUNDING COMPARISONS INDICATE THAT THE 00Z MODEL RUNS WERE
TOO DRY IN THE LOWER LAYERS. 12Z RUC DOES SEEM TO HAVE A HANDLE ON
THE MOISTURE AND IT FORECASTS CONTINUATION OF HIGH MOISTURE IN THE
LOWER LAYERS. VISIBLE IMAGERY TRENDS SHOW AN INCREASE IN CLOUDINESS
DURING THE PAST FEW HOURS AND LIKELIHOOD THAT AREA WILL SEE SOME SUN
LOOKS POOR... WITH THE EXCEPTION OF EXTREME NORTHERN COUNTIES. THIS
CLOUDINESS WILL ALSO INHIBIT TEMPERATURE RISES THIS AFTERNOON. WILL
UPDATE CURRENT FORECAST TO REFLECT THIS THINKING.
.LSE...NONE.
KRC
FXUS63 KMKX 241501 AMD wi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
339 AM CDT TUE AUG 24 1999
MAIN FOCUS WL BE ON SLOW EXIT OF UPR LOW FM RGN AND LINGERING PCPN.
CURRENT CONVECTIVE ACTIVITY ROTATING NWD FM IL INTO SRN WI AROUND UPR
LOW...LOCATED NR KDVN AT 06Z AS SHWN ON SATELLITE IR LOOPS. ACTIVITY
DVLPG ALONG AXIS OF SCNDRY H8 THERMAL RDG...DEPICTED BY 03Z RUC. SFC
DEW PTS IN THE 60S...WITH MSAS LI/S OF -1 TO -2...AHD OF SFC COLD FNT
PUSHING INTO W CNTRL IL.
VIGOROUS UPR LOW WL BE CENTERED OVR CNTRL IN BY 00Z...MAKING LTL EWD
PROGRESS AS NRLY STACKED SYSTM REACHES WRN OH AT 48 HRS. UPR RDG TO
WEST FLATTENS IN RESPONSE TO NEXT WAVE AS IT MOV INTO NRN PLAINS.
RESULT IS A GNRLY CYCLONIC EAST TO NE FLOW OVR SRN WI THRU PD. BUFKIT
MODEL SOUNDINGS KEEP COLUMN MOIST THRU LATE AFTN IN MSN...AND 06Z IN
MKE. NCEP MODELS HAVE 60 TO 70 PCT RH AT H7 THRU 00Z THU IN EAST.
MORNING SHRA/TSRA WL DIMINISH IN WEST..WITH CHC THIS AFTN. WL KPSCT
SHRA GOING FOR TDY ERN AREAS...AND EXTND CHC INTO EVE. WITH LINGERING
MID LVL MOISTURE...WL SLOW CLEARING OF CLD DECK...ESPCLY IN THE EAST
TNT AND WED. CLOUD COVER AND PCPN SHUD HOLD TEMPS CLOSER TO COOLER
FAN GUIDNC AND FWC 3 HRLY TEMPS.
COORD WITH ARX AND GRB
.UWNMS...NOT AVBL.
.MKX...NONE.
REM
FXUS63 KARX 240802 wi
FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
310 PM CDT TUE AUG 24 1999
IN SHORT TERM...VISIBLE IMAGERY INDICATES OUTFLOW BOUNDARY LOCATED
FROM NEAR GREENVILLE TO HATTIESBURG WHILE A SLOW SE MOVING COLD FRONT
EXTENDS ACROSS SRN AR/NRN MS. AIRMASS SOUTH AND SOUTHWEST OF THESE
FEATURES REMAINS VERY MOIST AND UNSTABLE AND WITH GOOD LOW LEVEL
THETAE ADV INTO REGION...EXPECT CONTINUED TSTM DEVELOPMENT THERE AS
WE PROGRESS INTO THE EARLY EVENING. AS OF NOW...AM PLANNING TO PUT
HI CHC POPS IN FOR SOUTHWEST COUTIES/PARISHES FOR EVENING ACTIVITY.
18Z RUC PICKS UP ON WEAK SHORTWAVE ENERGY ROTATING SOUTHWARD AROUND
UPPER LOW AND INTO NRN MS BY LATE EVENING. ASSUMING THAT AIRMASS CAN
RECOVER A LITTLE FROM EARLIER MCS...EXPECT THAT SOME SHOWER/TSTM
ACTIVITY WILL REDEVELOP OVER NE/E COUNTIES. SO WILL PUT SMALL POPS
IN THERE.
FOR WEDNESDAY/WED NIGHT...MODELS PROG THE WEAK SFC COLD FRONT TO
CONTINUE DROPPING SLOWLY SOUTHEAST ACROSS NRN/CNTRL PORTIONS OF FORECAST
AREA. AS THE UPPER LOW OVER THE OHIO VALLEY REGION PUSHES
EAST...SUBISIDENCE WILL TAKE OVER IN MID LEVELS WITH PRECIP WATER
VALUES GRADUALLY DIMINISHING OVER NRN PORTIONS OF THE AREA. SOUTH OF
THE SFC FRONT...MOISTURE/INSTABILITY WILL REMAIN HIGH...PARTICULARLY
OVER THE SOUTHEAST COUNTIES. SO WILL PUT HIGHEST POPS IN FOR SE MS
TOMORROW WITH LESSER POPS FURTHER NORTHWEST IN SOMEWHAT DRIER MORE
UNSTABLE AIRMASS. ACTIVITY SHOULD DIMINISH WITH LOSS OF DAYTIME
HEATING DURING EVENING.
FOR THURSDAY...DRY AIRMASS WILL CONTINE TO INFILTRATE FORECAST AREA
WITH SFC FRONT BECOMING ILL-DEFINED ACROSS SOUTHERN COUNTIES WHERE
SOME MOISTURE/INSTABILITY SHOULD BE ENOUGH FOR WIDELY SCT AFTN TSTM
DEVELOPMENT. WILL PUT SMALL POPS IN THERE.
QPF DISCUSSION: WEAK FRONTAL BOUNDARY WILL STALL OUT IN CENTRAL
MISSISSIPPI TONIGHT. IN WARM HUMID AIR AHEAD OF BOUNDARY...
WIDESPREAD RAINFALL WILL OCCUR...ESPECIALLY IN FIRST PERIOD. BY
SECOND PERIOD...MOST RAINFALL WILL OCCUR IN SOUTHEASTERN HALF OF
FORECAST AREA. ALTHOUGH SOME STORMS THIS EVENING WILL HAVE RAINFALL
AMOUNTS MORE THAN ONE INCH...OVERALL AVERAGE AREAL QPF SHOULD RXAIN
BELOW .50 INCH IN SOUTHEAST AND EAST CENTRAL SECTIONS OF THE
FORECAST AREA.
IN THE EXTENDED...MRF PROGGIX UPPER HIGH TO REMAIN DOMINANT OVER
WRN/CNTRL U.S WITH SHORTWAVE ENERGY ROTATING SOUTHWARD AROUND EAST
SIDE OF HIGH. MID LEVEL SHEAR AXIS PROGGED TO BECOME ESTABLISHED
ACROSS LOWER MS VALLEY. EXPECT INCREASING CHCS OF AFTN/EVENING TSTM
ACTIVITY THROUGH PERIOD.
.JAN...
MS...NONE.
LA...NONE.
AR...NONE.
43/15
FXUS74 KJAN 241625 ms
WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
245 PM MDT TUE AUG 24 1999
MODEL RUNS FROM THIS MORNING PLAGUED BY DRY BUG IN EARLY PERIODS. NOT
MUCH CONSISTENCY BETWEEN RUNS IN SHORT TERM EITHER. BEST MODELS FOR
TONIGHT PERIOD SEEM TO BE THE LATEST RUC AND 03Z ETA FROM LAST
EVENING. FIRST SHORTWAVE ROTATED ACROSS THE CWA THROUGH EARLY
AFTERNOON WITH ONLY SPRINKLES EXCEPT FOR CLOSER TO THE ID PANHANDLE
...GUSTS OVER 30KT ALSO ON A FEW RAWS SITES. DRYING ON WATER VAPOR
SPREADING ACROSS WESTERN MT THROUGH 20Z BROUGHT AMPLE SURFACE HEATING
TO THE WESTERN HALF OF CWA. CUMULUS/STORMS BUILDING RAPIDLY IN THIS
DESTABILIZING ENVIRONMENT OVER ID ZONES. SHORTWAVE TRIGGER NEAR KBKE
AT 19Z ON-TRACK TO SHIFT ACROSS CWA ALONG WITH INCREASE IN MID-LEVEL
WINDS...THIS LOOKS GOOD FOR ISOLATED TO SCATTERED CONVECTION THROUGH
THE EVENING HOURS. NEARBY 12Z SOUNDINGS HAVE INVERTED-V PROFILE AND
EXPECT FIRST BATCH OF STORMS TO HAVE STRONG WINDS AND DRY LIGHTNING.
WILL GO WITH ETA FOR LATER PERIODS. SHORTWAVE SHIFTS EAST OF DIVIDE
THIS EVENING AS UPPER WESTERLY FLOW INCREASES...WILL END T-STORMS BY
MIDNIGHT AS CONDITIONS STABILIZE. VERY STRONG WESTERLY JET ADVANCING
ACROSS THE PAC ENTERS SOUTHERN BC ON WEDNESDAY. UPSLOPE FLOW AND AN
INCREASE IN MOISTURE ACROSS NORTHERN MOUNTAINS SHOULD SUPPORT
ISOLATED SHOWERS AND COOLER TEMPS. WINDS OF 40KT AT H7 AND TIGHT
SURFACE GRADIENT TOMORROW FOR GUSTY WEST WINDS...ESPECIALLY
MOUNTAINS. RIDGING REBOUNDS ON THURSDAY WITH CA COASTAL LOW LOOKING
ALL TOO FAMILIAR. BOLDT
EXTENDED...MOISTURE INCREASES AGAIN FRIDAY AS CA LOW EJECTS WEAK
SYSTEM NORTHWARD. LOOKS FAIRLY DRY SATURDAY FOLLOWED BY MORE MAJOR
PAC TROUGH EDGING INLAND SUNDAY.
FXUS65 KGGW 242029 mt
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
217 PM EDT TUE AUG 24 1999
DISC: 18Z ANALYSIS SHOWS HI PRES TO OUR NE AND SFC LOW OVR THE MIDWEST.
SATELLITE SHOWS LOTS OF CLDS ACRS THE SE THIS AFT. SOME SUN ACRS EXTREME
SRN SC AND SRN GA. REGIONAL RADAR COMPOSITE SHOWS SHRA/TSRA FM SC SWWD
TO AL. MODELS IN PRETTY GOOD AGREEMENT WITH OVERALL TRENDS OF MOVG
CLOSED LOW EWD ACRS THE OH VALLEY THRU THE PD. THE LOW IS EXPECTED TO
WEAKEN AND LIFT NE BEYOND 48 HRS. AT THE SFC LOW AND ASSOCIATED FRNTL
BNDRY WL MOV SLOWLY EWD TO JUST W OF THE MTS. BUT FOR THE OVERNIGHT
HOURS...MODELS A BIT DIFFERENT IN PROGRESS OF S/W THAT IS NOW PRODUCING
THE PCPN ACRS THE SE. RUC/ETA SHOW S/W MOVG ACRS THE STATE OVERNIGHT TO
THE ERN PTN OF THE STATE BY MORNING. ONCE S/W MOVG ACRS STATE AIRMASS
BEGINS TO DRY OUT SOMEWHAT. A DESCENT AMOUNT OF LOW LVL MOISTURE IS
EXPECTED TO REMAIN AS SHOWN BY TIME SECTIONS. ETA SHOWING GOOD AREA OF
UVV MOVG ACRS STATE TON. WL GO WITH LIKELY POPS FOR MOST AREAS TON THEN
LWR TO SML CHC FOR WED.
.CAE...NONE.
LCV
FXUS62 KGSP 241746 COR sc
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
145 PM EDT TUE AUG 24 1999
UPPER LOW TO PROGRESS SLOWLY E THROUGH 48 HOURS...OPENING UP
AND LIFTING OUT BY 72 HOURS. TIME SECTIONS SHOW DEEP MOISTURE
UNTIL 06-12Z WED WHEN HIGH/MID LEVELS DRY AND LIFT ENDS. RUC SHOWS
MID LEVEL DRYING BEGINNING THIS EVENING. WED-THU HAVE WEAK
DOWNWARD MOTION WITH LOW LEVELS REMAINING MOIST. EXPECT WEAK
STATIONARY FRONT TO REMAIN S OF AREA WHILE DECAYING. RIDGE NOT FAR
ENOUGH OFFSHORE WED TO ALLOW WINDS TO COME AROUND TO S...BEST BET
IS NE WED. WILL GO ABOVE GUIDANCE POPS WED SINCE DVV ARRRIVES
LATER IN DAY AND MORNING MAY REMAIN ACTIVE. CLOUDS HOLD WED/WED
NIGHT WITH NE FLOW. THU MORE COMPLEX AS MODELS BRING REMNANTS OF
COLD FRONT CROSS AREA EARLY...WHILE AVN/MRF BRING TROPICAL SYSTEM
UP FROM BAHAMAS. FWC HAS E WIND. AT THIS TIME WILL LEAVE CLOUDS
AND POPS INDICATIVE OF PERSISTANT LOW LEVEL MOISTURE. MAXIMUMS
TEMPERATURES TO WARM EACH DAY AS CLOUDS THIN/BREAK. MINIMUMS
SHOULD REMAIN STEADY AS LOW LEVEL MOISTURE REAMINS HIGH.
AVL 64/76/63/82 7533
CLT 67/79/67/86 7533
GSP 68/80/67/87 7533
.GSP...NONE.
JAT
FXUS62 KGSP 241745 sc
COASTAL BEND FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
210 PM CDT TUE AUG 24 1999
MUCH QUIETER AFTERNOON THAN PREVIOUS TWO DAYS. REMNANTS OF BRET
CONTINUE TO MOVE FARTHER AWAY FROM CWA REDUCING THE THREAT OF RAIN.
WILL NOT COMPLETELY REMOVE POPS DUE TO ABUNDANT MOISTURE STILL IN
PLACE. PWATS PROGD TO DECREASE OVER NEXT 48 HRS AS MID AND UPPER
LEVEL HIGH BUILDS SOUTHWARD INTO S TX. TIME CROSS SECTIONS ALSO
INDICATE DRYING AT MID AND UPPER LEVELS WITH WINDS WEAKENING AND
BECOMING SELY AT THESE LEVELS. SFC WINDS HAVE BEEN AVERAGING 15KT
WITH SOME GUSTS TO 20KT AND GENERALLY OUT OF THE EAST ACROSS THE
CWA. SFC WINDS PROGD TO REMAIN BASICALLY THE SAME THROUGH WEDNESDAY.
DAYTIME HIGHS WILL BE BACK INTO THE 90S OVER A MAJORITY OF CWA. SEA
BREEZE MAY PRODUCE ISOLATED/WIDELY SCT SHOWERS WITH ENOUGH MOISTURE
STILL IN PLACE FOR WEDNESDAY. LOOKS LIKE WE ARE BACK TO OUR NORMAL
SUMMER TIME FORECAST.
EXTENDED...MRF PROGS UPPER TROUGH AXIS TO DIP INTO SOUTH TEXAS WITH
SFC FRONT WORKING ITS WAY INTO SE TX BY SATURDAY. MAY AFFECT N CWA
WITH CONVERGENCE OF SEA BREEZE. MRF ALSO PROGS WEAK EASTERLY WAVE TO
MOVE INTO MEXICO S OF BRO. CURRENT IR SATELLITE AND RUC SHOW WEAK
UPPER LEVEL DISTURBANCE NEAR YUCATAN MOVING WEST. SLIGHT CHANCE OF
PRECIP IN EXTENDED LOOKS GOOD FOR NOW.
MARINE...ONSHORE WINDS EXPECTED TO REMAIN BELOW SCA CONDITIONS.
CRP BB 076/092 076/095 075 2211
VCT BB 074/095 075/096 074 2211
LRD BB 074/091 075/095 074 2211
BML.76/TP.81/BSB.91
.CRP...NONE.
FXUS64 KLUB 241901 tx