INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
300 PM PDT SUN SEP 12 1999
REX BLOCK IN PLACE WITH CLOSED UPPER LOW JUST WEST OF SFO...AND HIGH
AMPLITUDE RIDGE FROM THE PAC NW INTO WESTERN CANADA. MODELS SIMILAR
IN GRADUALLY MOVING BLOCK INLAND BY 48HRS...WITH UPPER LOW MOVING
INTO NRN/CENTRAL CA. MODELS DIFFER CONSIDERABLY ACROSS CENTRAL CA
WITH RESPECT TO DYNAMICS AND RH FIELDS IN THE LOW LEVELS.
DEW PTS TODAY HAVE INCREASED FAIRLY DRAMATICALLY IN THE DESERTS...
WITH DAG AND EDW UP ALMOST 20 DEGS SINCE EARLY EARLY MORNING...AND
MORE CONVECTION THAN YESTERDAY AT THIS TIME. WITH UPPER LOW MOVING
CLOSER...UPPER FLOW WILL WEAKEN. DONT SEE ANYTHING THAT WILL MAKE
LOW LEVEL MOISTURE OVER SOCAL GO AWAY. RUC SHOWS SOME WEAK
DIVERGENCE ALOFT TO AID IN CONVECTION DESPITE MINIMAL LI/S. WITH
CHANGES OVER THE NEXT 48HRS EVER SO SLOW...WILL MAINTAIN PRESISTENCE
AND KEEP ISOLD T-STORMS OVER THE SIERRA CREST. GRADIENTS EVERYWHERE
WEAK TO NIL...AND WILL DROP ALL MENTION OF WINDS. TEMPS SLIGHTLY
LOWER TUES AS LOW MOVES OVERHEAD.
NEW AVN FINALLY IN...AND SHOWS VERY LITTLE OVERALL CHANGE THRU
48HRS. UPPER LOW CONTS TO MOVE VERY SLOWLY TO THE EAST...REACHING
WESTERN NV WED MORNING. WITH VERY WEAK FLOW ALOFT...MAY STILL SEE
ISOLD MTN STORMS INTO WED. FOR THE REMAINDER OF THE EXTENDED...
NO LARGE SCALE CHANGES SEEN...WITH TEMPS NEAR OR A LITTLE ABOVE
NORM. FAT/BFL 0000 YNP 0-0-
.HNX...NONE.
FAT HU 062/095 062/092 061 85000
BFL UU 064/094 063/092 061 85000
YNP BB 052/088 051/085 050 850-0
FXUS66 KMTR 122155 ca
SOUTH CENTRAL AND SOUTHEAST COLORADO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO
300 AM MDT SUN SEP 12 1999
...FORECAST CHALLENGE NEXT COUPLE PERIODS REVOLVE AROUND CLOUD COVER
AND IMPACT ON TEMPERATURES...
CURRENT OBS AND RADAR SHOW SURFACE FRONT JUST SOUTH OF THE ARKANSAS
RIVER WITH MODELS IN GOOD AGREEMENT ON SURGING FRONT THROUGH THE
REMAINDER OF THE SOUTHERN ZONES BY AROUND FORECAST ISSUANCE TIME.
NORTHERLY WINDS 20-30 MPH BEHIND THE FRONT WILL CONTINUE THROUGH THE
MORNING HOURS BEFORE DIMINISHING BY MID MORNING. FOG PRODUCT SHOWS
STRATUS DECK ADVANCING SOUTHWARD AS OF 08Z WITH SOME LOW CIGS...BUT
DEW POINTS DROPPING AND LACK OF AN UPSLOPE WIND COMPONENT KEEPING FOG
FROM DEVELOPING. WILL WATCH HOW THINGS PROGRESS UNTIL RIGHT AT ZONE
ISSUANCE FOR THE FOG...BUT FOR NOW DON'T EXPECT FOG TO BE WIDESPREAD.
AS STRATUS DECK ADVANCES ACROSS THE SOUTHEAST PLAINS...EXPECT SKIES
TO STAY CLOUDY FOR THE MAJORITY OF THE DAY. CROSS-SECTIONS SHOW
CLOUD DECK AT 700 MB AND BELOW HANGS IN FOR MOST OF THE DAY...WITH
RUC SHOWING A LITTLE DRYING ALONG THE MOUNTAINS TOWARDS AFTERNOON.
DRY AIR ABOVE IN SUBSIDENT REGION MAY ALLOW SOLAR HEATING TO PRODUCE
SOME BREAKS IN THE CLOUDS DURING THE AFTERNOON...HOWEVER AS SURFACE
HIGH DIVES THROUGH THE CENTRAL PLAINS...WINDS SWING AROUND FROM A
LIGHT EASTERLY DIRECTION BY TONIGHT WHICH MAY BRING LOW CLOUDS BACK
IN. 700 TEMPS SUPPORT AT LEAST A 10 DEGREE COOL DOWN EAST OF THE
MOUNTAINS TODAY...AND WITH CLOUD COVER HANGING IT...15 TO 20 DEGREE
COOL DOWN SEEMS MORE IN LINE. GUIDANCE LOOKS MORE REASONABLE THAN
LAST FEW RUNS...HOWEVER WILL STILL UNDERCUT...ESPECIALLY FOR THE
EAST. OTHER CONCERN IS ANY RESIDUAL SHORTWAVE ENERGY THAT MAY
ADVANCE SOUTHWARD ALONG THE WEST SIDE OF UPPER TROUGH. MODELS KEEP
UPPER ENERGY WELL NORTH OF THE FORECAST AREA TODAY WITH QG DESCENT
OVER THE REGION. ATMOSPHERE IS PRETTY DRY ABOVE 700 MB ANYWAY...AND
WITH STABLE SURFACE INVERSION DON'T EXPECT ANY SHOWER ACTIVITY THIS
AFTERNOON. MAY STILL A FEW RESIDUAL SHOWERS EMBEDDED IN STRATUS
THIS MORNING...BUT THESE SHOULD MOVE OUT FAIRLY QUICKLY.
TONIGHT...MODELS IN GOOD AGREEMENT TURING WINDS FROM EASTERLY TO
SOUTHEASTERLY COMPONENT OVERNIGHT. ALL MODELS ALSO BRINGING LOW
LEVEL CLOUDS BACK IN OVERNIGHT...ESPECIALLY IN THE SOUTHERN ZONES.
IF MODELS VERIFY...THIS WILL KEEP OVERNIGHT TEMPERATURES WARMER OVER
THE SOUTHERN ZONES...WITH FROST POTENTIAL LOW. HOWEVER COLDEST AIR
AND BEST POTENTIAL FOR CLEARING SKIES WILL BE IN THE NORTHEASTERN
PORTIONS OF THE FORECAST AREA. AGREE WITH PREVIOUS SHIFT THAT FROST
POTENTAIL SHOULD BE FAIRLY ISOLATED AND PROBABLY NOT WIDESPREAD
ENOUGH TO WARRANT ANY ADVISORIES. WILL TREND ZONES WITH COLDEST
OVERNIGHT TEMPERATURES AND CLEAR SKIES IN ZONES 71/72 AND 78...AND
WILL THROUGH IN SOME PARTLY CLOUDIES AND SLIGHTLY WARMER TEMPERATURES
IN THE SOUTHERN ZONES.
MONDAY LOOKS DRY AND COOL MOST AREAS...WITH POSSIBLY SOME RESIDUAL
CLOUD COVER IN THE SOUTHEAST DURING THE MORNING. HOWEVER MOISTURE IS
MORE SHALLOW AND ANY CLOUD COVER SHOULD BURN OFF QUICKLY. CURRENT
ZONES HAVE MOSTLY SUNNIES AND WITH UNCERTAINTIES ON THE EXTENT OF
MORNING CLOUD COVER...WILL STAY WITH THE GOING FORECAST AND LET NEXT
SHIFT LOOK AT POTENTIAL FOR ADDING IN SOME MENTION OF MORNING
CLOUDS.
EXTENDED: ANOTHER SHORTWAVE ROTATING DOWN THE WEST SIDE OF SLOW
MOVING UPPER TROUGH WILL SEND ANOTHER SURFACE COLD FRONT THROUGH
THE EASTERN PLAINS LATE TUESDAY INTO WEDNESDAY. LOW LEVEL MOISTURE
INCREASES FOR WEDNESDAY AND THURSDAY IN EASTERLY FLOW...WHILE HIGH
LEVEL MOISTURE ALSO INCREASES AHEAD OF UPPER TROUGH WHICH FINALLY
MOVES INTO THE GREAT BASIN BY THURSDAY. MODELS SHOW ENOUGH
MOISTURE AND DYNAMICS TO SUPPORT CHANCE POPS WED AND THURS. AM
SOMEWHAT SKEPTICAL ABOUT THE AMOUNT OF MOISTURE THE MRF IS
ADVERTISING ESPECIALLY OUT ON THE EASTERN PLAINS BEHIND THE CANADIAN
FRONT WHERE ONE WOULD EXPECT A DRIER AIRMASS TO BE FOUND. BUT WITH
SHORTWAVE MOVING INTO GREAT BASIN THERE IS LIKELY TO BE SOME MID AND
HIGH MOISTURE. WILL NOT MAKE ANY CHANGES TO THE EXTENDED FORECAST.
.PUB...NONE.
KT
co
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
227 PM MDT SUN SEP 12 1999
ATTM SFC HIGH PRESSURE WAS CONTINUING ITS MOVEMENT INTO THE CENTRAL
PLAINS. STRONG MID LVL LOW CONTS OVR THE UPPER MISSISSIPPI VALLEY
KEEPING PRESSURE GRADIENTS TIGHT ACRS THE TRI-STATE AREA. LOW/MID LVL
CLOUD COVER WAS PERSISTING OVR THE SOUTHERN HALF OF THE CWA AS COLD
AIR CONTS TO ADVT INTO ALL OF THE FA. ETA SEEMED TO BE ON A BETTER
TRACK THAN THE NGM WITH THE DIMINISHING CLOUD COVER ACRS THE AREA.
SFC WINDS BECOME NNE AND DECOUPLE ACRS THE WESTERN FA TONIGHT
PRODUCING A SLIGHT UPSLOPE WHICH MAY KEEP/DEVELOP THE LOW/MID LVL
CLOUD COVR OVER THIS AREA. ALSO AS WARM AIR ADVTS ACRS THE MID LVLS
WITH COOLR AIR AT THE SFC THE POTENTIAL FOR DEVELOPING CLOUDS AGAIN
IS POSSIBLE OVR THE W FA. IF THIS OCCURS...AS THE MODELS INDICATE...
OVERNITE LOWS SHUD REMAIN ABOVE FREEZING SO THE CONCERN FOR FROST
SHUD BE MINIMAL. BUT...THE LATEST SATELLITE SHOWED CLOUD COVER
DECREASING AND THE RUC INDICATED THIS ALSO INTO TONIGHT. IF THIS
HAPPENS...THE POSSIBILITY OF FROST INCREASES BUT AFTER VIEWING THE
LAMP DATA...AGREE THAT SFC TMPS/DEW POINTS SHUD REMAIN ABOVE FREEZING
REGARDLESS OF CLOUD COVER.
THE MID LVL LOW WILL DRIFT EAST AND WITH THE SLOW INCREASE IN
5H/HGHTS AND THCKNS...ANOTHER BELOW AVE TEMPERATURE DAY IS LIKELY
TOMORROW. THE POSSIBLE CLOUD COVER OVR THE WESTERN FA DRIFTS INTO THE
CENTRAL AND EASTERN CWA MONDAY AND SHUD HOLD TOGETHER AS MID LVL WARM
AIR CONTS TO ADVT OVR THE COOL LOWR LVL TMPS BUT AS IT DOES...IT
SHUD SLOWLY ERODE THEREFORE WILL GO WITH PARTLY CLOUDY SKIES.
ANOTHER COOL MONDAY NITE IS IN STORE FOR THE FA WITH A SLIGHT WARM
UP TUESDAY. SFC WINDS VEER INTO THE SOUTH AND MID LVL MOISTR
INCREASES. AFTN CLOUDS SHUD DEVELOP AND WITH AN APPROACHING 5H/VORT
MAX FROM THE WEST...A FEW TSRA MAY DEVELOP LATE IN THE AFTN AND
POSSIBLY INTO THE EVENING.
FOR THE EXTENDED A STRONGER 5H/DISTURBANCE MOVES INTO THE CENTRAL
PLAINS WEDNESDAY AND WITH MID LVL MOISTR PERSISTING THE CHANCES OF
TSRA WILL INCREASE FOR THE CWA. THIS DISTURBANCE APPEARS SLOW TO
MOVE THEREFORE WILL KEEP POPS IN THE FORECAST THURSDAY. BY THE END
OF THE WEEK 5H/HI PRESSURE BUILDS INTO THE AREA AND AFTN TMPS SHUD
WARM WITH DIMINISHING POPS.
.GLD...NONE.
VPAPOL
FXUS63 KICT 121959 ks
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON KY
920 PM EDT SUN SEP 12 1999
HAND ANALYSIS OF 00Z SFC CHART SHOWS THE COLD FRONT THRU CNTRL IN AND
SWRD TO NEAR EVV AND PAH AND ON DOWN TO JBR AND PBF AREAS. THIS IS
A TAD FASTER THAN THE 12Z ETA AND NGM FCST FOR 00Z. 21Z RUC WAS
PRETTY CLOSE. ALSO NOTED THAT A LOT OF THE -RA ACTIVITY WAS AT OR
BEHIND THE FRONT...POST FRONTAL TROFF ALSO EVIDENT DROPPING DOWN ACRSS
WI/IL/E. MO...
SAT PIXS SHOWING RATHER AMPLE AMOUNTS OF MID LEVEL CLDS INVADING THE
CWA WITH SOME LOWER CLDS BACK CLOSER TO THE FRONT. 88DS AND REGIONAL
RADAR COMPOSITE LOOPS SHOWING SOME LIGHT SHRAS FLIRTING WITH THE
WESTERN FRINGES OF THE CWA. THINK MOST OF THIS ACTIVITY IS PRETTY LIGHT
AND SOME MAY EVEN BE VIRGA...ESP ON THE LEADING EASTERN EDGES. BUT
WITH THE BNDRY SLOWLY APPROACHING LOW POPS WARRANTED ESP AFTER MIDNIGHT
OR TOWARD MORNING.
WILL UPDATE ZONES TO TWEAK CLOUD COVER AND ADD LOW POPS FOR W 1/2-2/3
OF THE AREA. THIS ALSO FORCES ME TO REWORD TOMORROWS INCREASING CLOUDS
WORDING TO MC. ONGOING POPS FOR TOMORROW LUK A LITTLE LOW BUT WILL
LEAVE ALONE FOR NOW AND TRY TO AVOID FLIP-FLOPPING ALL OVER THE
PLACE...AS WELL AS TRYING TO LEAVE SOME CONTINUITY GOING FROM DAY
SHIFT PACKAGE.
.JKL...NONE.
HALL
FXUS63 KLMK 121904 ky
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
950 AM EDT SUN SEP 12 1999
IR/VIS LOOPS SHOWING A DISSIPATING AREA OF HIGH CLOUDINESS ACROSS THE
FA AT TIME. LOW RH VALUES FROM 300 TO 500 MB ON 09Z RUC SUGGEST THAT
THIS TREND WILL CONTINUE THROUGH THE AFTERNOON. WILL GO WITH MSUNNY
FORECAST THIS AFTERNOON FOR ENTIRE FA.
TEMPS FROM THIS MORNINGS CO-OP REPORTS SHOWED HIGHS YESTERDAY AROUND
THE 80 DEGREE MARK FOR MOST OF THE AREA... WITH A FEW READINGS AROUND
82 OR 83 IN THE SHENANDOAH VALLEY. 850 MB TEMPS THIS AFTERNOON SHOULD
BE SIMILAR TO YESTERDAY'S READINGS.. AND 12Z IAD SOUNDING INDICATES
A HIGH AROUND 81 DEGREES. MAX TEMP FORECASTS FOR AFTERNOON WILL BE
AROUND 80 FOR THE ENTIRE AREA.
.LWX...NONE.
MARGRAF!
md
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
945 PM EDT SUN SEP 12 1999
LARGE UPPER LO OVER N MN IS DOMINATING THE WX IN THE U.P. WITH THE
SFC LO OCCLUDING JUST NORTH OF LS. DRY AIR HAS WORKED IN FROM THE
SOUTH INTO THE U.P THIS EVENING ALLOWING FOR MAINLY DRY CONDITIONS.
BUT THERE ARE EXCEPTIONS. THE OCCLUSION HAS SPARKED SOME FAIRLY
POTENT TSTMS OVER EASTERN LS WHERE THERE IS A LITTLE CAPE. THESE
STORMS ARE HEADING NE AT 30 KTS AND SHOULD BE OUT OF THE CWA BY
MIDNIGHT.
THE 21Z RUC SHOWS A PV LOBE SPINNING AROUND THE UL LOW OVER WESTERN
LS AT 00Z. THE LIFT ASSOCIATED WITH THE PVA IS HELPING TO SUSTAIN A
LINE OF MOSTLY SHRA /SOME THUNDER/ MOVING EAST. WINDS HAVE BEEN
CLOSE TO 30 MPH WITH THE LINE SO WILL INSERT A GUSTY SHOWER IN THE
CENTRAL COUNTIES OVERNIGHT. THE RUC ALSO SHOWS ANOTHER SHRTWV OVER
CENTRAL MN AT 00Z. THIS LINES UP WELL WITH SHRA NW OF MSP. THE
SHRTWV IS PROGGED TO BE NEAR IWD BY 09Z...SO WILL LEAVE IN THE
MENTION OF A SHOWER WEST.
A DAY MUCH LIKE LAST THURSDAY ON TAP FOR TOMORROW WITH INSTABILITY
SHRA WORKING IN FROM THE WEST DURING THE AFTERNOON.
.MQT...NONE.
ALTOE
FXUS63 KDTX 130149 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1215 PM EDT SUN SEP 11 1999
15Z SFC ANAL SHOWS AREA OF LOW PRES /1007 MB/ NR ONTONAGON ROTATING
SLOWLY NORTH AROUND PARENT UPR LVL LOW. UPR LVL LOW OVR NE NO DAK
PER GOES-8 WV DATA WITH SERIES OF VORT LOBES ROTATING AROUND LOW.
FIRST IN SERIES OF VORTS MOVG INTO ERN LK SUPERIOR WITH SECOND
SHEARING OUT ACROSS CNTRL WI TO CNTRL IA. ELONGATED AREA OF SHWRS
AND EMBEDDED TSTMS IN REGION OF DIFF PVA AHEAD OF VORT XTNDNG FM ERN
LK SUPERIOR ACROSS CNTRL U.P. TO SW WIS. WITH UPR SUPPORT RACING OFF
TO THE EAST PER WV DATA... LINGERING SHWRS OVR KEWEENAW AND CNTRL UPR
MI IN REGION OF WEAKER ISENT LIFT ALONG/AHEAD OF SFC WMFNT HAVE
DECREASED CONSIDERABLY IN COVERAGE AND INTENSITY.
WITH LOW LVL DRYING LAGGING BEHIND DEPARTING UPR LVL VORT... XPECT
SPOTTY SPRINKLES/LGT SHWRS TO PERSIST FOR ANOTHER 1-3 HRS BUT
GRADUALLY END FM SW TO NE AS MID-LOW LVL DRY SLOT PUNCHES INTO UPR MI
FM THE SW. NEXT IN A SERIES OF VORT LOBES APPARENT IN GOES-8 IR AND
WV DATA AND WSR-88D DATA WITH LOBE OF CLDS/PCPN XTND AS FAR S AS DLH
INTO NW WISC. WITH CLRNG BHND THIS LINE... AXIS OF DIFF HEATING MAY
SERVE TO INTENSIFY LOW LVL BOUNDARY THIS AREA. WITH 95 KT UPR LVL
JET STREAK MOVG ACROSS UPR MISS VALLEY THIS AFTN WRN UPR MI COMES
UNDER FAVORABLE LEFT FRONT QUAD WITH AREA OF DIVERGENCE ALOFT. ASCENT
FORCED BY JET COMBINED WITH THAT OF THE VORT AND POSSIBLE FOCUSING
MECHANISM IN SFC BOUNDARY... FEEL SHWRS/TSHWRS MAY REDEVELOP FAR WRN
U.P. BY MID AFTN AND THEN LIFT NE INTO KEWEENAW BY LATE AFTN.
WITH DRY SLOT NOSING INTO WRN/CNTRL U.P. FM THE SW... RUC SHOWING LOW
AND MID LVL MOISTURE PERSISTING LONGER OVR ALGER/LUCE/DELTA/
SCHOOLCRAFT COS AS PIVOTING NATURE OF UPR LVL FEATURES AND MORE SRLY
FLOW ALOFT THIS REGION RETARDS LOW LVL DRYING.
WITH ABUNDANCE OF CLDS XPECT DIURNAL RISES IN TEMPS TO BE SMALL. SFC
WINDS WILL GRADUALLY SHIFT MORE S TO SW FM SW TO NE AS SFC WMFNT
LIFTS NORTH OF THE U.P.
.MQT...NONE.
ED F
FXUS63 KGRR 121607 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1103 AM EDT SUN SEP 12 1999
SHRA/EMBEDDED TSRA ARE DEVELOPING ACROSS LAKE MI LATE THIS MORNING
IN AN AREA OF INCREASING WAA AND THETA E ADVECTION VIA A
STRENGTHENING 850 MB JET PUNCHING INTO THAT REGION AHEAD OF THE COLD
FRONT. ELEVATED CONVECTION N OF THE WARM FRONT OVER FAR NRN LAKE MI
IS MOVING ONSHORE ACROSS ERN UPR MI ATTM...BUT IS GENERALLY
DIMINISHING WITH TIME AS IT MOVE ONTO COOLER LAND AND FURTHER AWAY
FROM BETTER LIFT JUST N OF THE WARM FRONT.
RUC AND ETA PROG THETA E RIDGE AHEAD OF THE FRONT TO BE DIRECTLY
OVER LOWER AND ERN UPR MI BY 21Z. THIS SEEMS REASONABLE AS THE SFC
AND UPPER SYSTEM WILL SLOW A BIT AS IT OCCLUDES TOWARD EVENING.
INSTABILITY AND LIFT WILL BE SOMEWHAT LACKING THIS AFTERNOON. 12Z
MODIFIED APX SOUNDING YIELDS ONLY 300 CAPE AND LI'S OF -1 FOR THE
AFTERNOON. IN ADDITION...BEST Q-VECTOR CONVERGENCE SLIDES N AND E OF
THE CWA WITH THE OCCLUDING LOW. BEST LIFT WITHIN THE CWA WILL BE
OVER ERN UPR MI IN PROXIMITY TO THE BETTER UPPER FORCING.
WILL GENERALLY STICK WITH GOING CLOUD/PRECIP FORECAST...BUT WILL
WORD AS SCT SHRA AND A FEW TSRA ACROSS ERN UPR AND NW LOWER. WILL
ALSO INCLUDE MENTION OF THUNDER FOR ERN UPR MI. WILL HAVE TO BUMP
FORECASTED HIGHS UP A BIT AS PLENTY OF SUN THUS FAR HAS DRIVEN TEMPS
UP TO NEAR 70 TO THE LOWER 70S ALREADY.
.APX...NONE.
EME
FXUS63 KDTX 121443 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DULUTH MN
230 PM CDT SUN SEP 12 1999
ALL OF THE MODELS PICKED OUT THE DRY SLOT THAT PENETRATED OUR SWRN
CWA FOLLOWING THE TRIPLE POINT LOW...AND ARE SIMILAR IN MOV IT EWD
ACRS OUR WI COUNTIES TONITE AS MSTR INVADES MN AGN ON BACK SIDE OF
SYSTM. OTHR MODEL DIFF APPEAR MINOR. WILL CONT FOLLOWING ETA FOR
DETAILS IN COVERAGE AND TIMING. IN THE MEANTIME...ONE VORT MAX
EXITING CWA TO N AND TAKING SHRA WITH IT. NXT ONE MOV OUT OF ERN ND
TWD AREA THAT HAS RECEIVED SOME SFC HTG THIS MRNG. THIS CLR RGN IN
SWRN CWA HAS FILLED BACK IN WTH CU...AND XPCT TO SEE REDVLPMT OF
SHRA AND EVEN TSTMS AS COLD POOL ALOFT SWINGS ACRS TO AID
DESTABILIZATION. RUC BRINGS IN -6 LI/S LATE THIS AFTN AND EVNG.
BEYOND THAT...MSTR/CYC CURV HANGS ON INTO TUE...SO WILL HAVE TO
CARRY AT LEAST CHC POPS THRU 3RD AND 4TH PDS. LAST VORT MAX ROTATES
OUT OF RGN TUE NGT...FOLLOWED BY TEMPORARY UPR RIDGING. PLANNING ON
A DRY EXTENDED PD. WTH CLD CVR...DO NOT XPCT MUCH DIURNAL CHG IN
TEMPS. FWC HIGHS HAVE COME DOWN A BIT FRM PVS RUNS AND APPEAR MORE
CONSISTENT WTH ACTUAL READINGS. LOWS IN UPR 40S LOOK OK...MAYBE A
BIT LOWER IN SRN MN/WI ZONES WHERE CLD CVR WILL BE A LITTLE LESS. IN
SHORT...CURRENT ZFP PKG SHOULD ONLY NEED MINOR ADJUSTMENTS...XCPT
FOR ADDING CHC POPS TO TUE.
.DLH...NONE.
ERF
FXUS63 KMPX 121558 COR mn
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
937 AM EDT SUN SEP 12 1999
NO PROBLEMS THIS AFTN AS HI PRES CONTINUES TO RULE AT THE SFC & ALF.
S/WV SEEN ON SAT PIX DRIFTING BY TO OUR W IS TRYING TO SPILL SOME CI
OVER US BUT HAVING A HARD TIME OVERCOMING DRY AIRMASS. WILL CONTINUE
MOSNY AS SOME MOISTENING WILL ALLOW SCT CI. LO-LVL THICKNESS SCHEMES
FROM 12Z SOUNDINGS AS WELL AS LAMP GUIDANCE & LOCAL TEMP SCHEMES
GIVE AFTN TEMPS IN THE LWR-MID 80S WHILE AWIPS FCST MAX TEMPS FROM
RAOBS SHOW UPR 80S TO ARND 90. MAY LOWER TEMPS ACROSS THE COASTAL
COUNTIES SOME TO ACCOUNT FOR THIS... OTHERWISE NO CHANGES PLANNED.
CWF: SWELL FRONT NOW THRU 41001/41002. SEAS WON/T CHANGE MUCH BUT
WILL INTRODUCE A SERLY SWELL INTO THE CWF. WINDS OFF LATEST RUC SHOW
AN INCREASE TO 20 KT BY LATE AFTN WHILE 03Z MESO-ETA KEEPS THEM IN
10-15 KT RANGE. COMPROMISE IS 15 KT WHICH IS CURRENT FCST SO NO
CHANGES PLANNED THERE.
.ILM...NONE.
LGE
nc
FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
1015 AM CDT SUN SEP 12 1999
UPDATE PLANNED. WELL DEVELOPED EXTRATROPICAL CYCLONE OVR NRN PLAINS.
SFC LOW INTO NERN WI WHILE UPR LOW APPRS JUST NORTH OF DVL. DRY SLOT
EXTENDING WELL INTO SRN MAN...WHILE COMMA HEAD CLOUDS WRAPPING
RAPIDLY AROUND UPR LOW THROUGH WRN ND. CLOUD FREE AREAS OF SERN ND
AND WCNTRL MN LIKELY TO FILL IN AS CLOUDS ADVECT IN AND MID LVLS
COOL. MAX TEMPS MAY EDGE INTO LOW 60S THERE BEFORE OVRCST MOVES IN.
SHOWERY CONDITIONS FROM NCNTRL ND TO SPREAD/DVLP EWD AHEAD OF VORT
MAX IN COMMA HEAD. RRV ZONES TO REMAIN DRY THROUGH EARLY AFTERNOON
...THEN FILL IN WITH WIDESPREAD CONVECTIVE PRECIP UNDER COMMA HEAD.
IN NRN MN...ENHANCED SHOWERS MOVING THROUGH BDE THROUGH AM WITH HARD
BACK EDGE OF VORT LOBE SHOWING IN VIS IMAGERY EAST OF ROX-AIT LINE.
PRECIP AMOUNTS SHOULD RANGE UPWARD OF A HALF INCH ACROSS NRN ZONES
TDY AND TNGT WITH 00Z ETA AND 06Z RUC DRAWING HEAVIEST AMOUNTS
THROUGH THERE. SRN ZONES WILL HAVE SPOTTIER PRECIP TDY AND TNGT WITH
MORE CONVECTIVE ELEMENTS....AND PRECIP AMOUNTS RANGING FROM A FEW
HUNDRETHS TO A HALF INCH OR SO.
.FGF...NONE.
GUST
nd
CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
910 PM EDT SUN SEP 12 1999
INTERESTING VORT MAX WENT BY AT HI LVLS THIS AFTN WITH SOME CB TOPS
DEVELOPING WITH BASES ABOVE 15KFT. NO PRECIP ANYWHERE BUT LOTS OF
SNOW VIRGA COMING OUT OF CB TOPS. RUC SHOWED THIS NICELY. WHAT IS
LEFT OF THIS HI LVL CONVECTION IS UP OVR SW NEW ENG.
24 HR TEMPS 4 TO 8F WARMER THAN YDY AT THIS TIME. ERI IS 14F
WARMER. AFTN TEMPS REACHED THE LOW 90S OVR OH IN SW FLO JUST AHEAD
OF APROACHING CFRNT. MODELS DO NOT BRING THAT AIR E OF MTNS AT THE
SFC OR AT 85H. WITH THE SFC HI TO THE NE OF OUR BEAUTIFUL STATE
THERE COULD BE A CASE MADE FOR A COOL AIR DAM...IF THERE WERE CLDS
TO HOLD TEMPS DOWN. FWC TMPS RAN 3F TOO COOL TDY AT MDT AND WILL
PROB BE ABOUT THE SAME TOM. SUBSTANTIAL CLD WILL NOT REACH LWR SUSQ
TIL MID TO LATE AFTN AND THIS WILL ALLOW FULL INSOLATION. WITH RISK
OF A BIG BUST ON THE WARM SIDE WILL BUMP TEMPS UP JUST A BIT FOR MON.
OTHW NO CHANGES.
EUROPEAN HAS BEEN MOST CONSISTANT WITH EVENT THIS COMING WEEK. OTHER
MODELS ARE BACKING OFF A LANDFALL BUT HAVE BEEN INCONSISTANT. AS
USUAL...WE MUST WAIT AND SEE.
.CTP...NONE.
HEAD
FXUS61 KPBZ 121857 pa
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
800 PM MDT SUN SEP 12 1999
SKIES HAVE BECOME MOSTLY CLEAR OVER MOST OF NERN WY AND WRN SD...
WITH PARTLY CLOUDY SKIES OVER CNTRL SD. NORTHWEST WINDS HAVE FALLED
BELOW ADVISORY CRITERIA...BUT THE SURFACE PRESSURE GRADIENT STILL
WAS SIGNIFICANT ENOUGH TO CAUSE 15-35 MPH WINDS OVER NWRN-CNTRL SD.
HOWEVER...WITH THE CLEARING SKIES THE WINDS SHOULD CONTINUE TO
DECREASE...AND SHOULD FALL TO 5-15 MPH OVER NERN WY AND WRN SD.
ALSO OF INTEREST...THE SURFACE DEWPOINTS VARIED FROM THE UPPER 20S
OVER NERN WY...TO NEAR 30 OVER WRN SD...AND TO 35-40 OVER CNTRL SD.
THIS GENERALLY FITS WITH THE GOING FREEZE/FROST ADVISORIES. THE
MAIN CONCERN IS HOW MUCH WILL THE WIND SUBSIDE. THE 00Z RUC MODEL
SUGGESTS THE SURFACE PRESSURE GRADIENT WILL RELAX ENOUGH FOR THE
DECREASE IN WINDS SPEEDS...THUS WILL LEAVE THE CURRENT FREEZE/FROST
ADVISORIES AS IS.
.UNR...FREEZE ADVY NERN WY TONIGHT.
FROST ADVY MOST OF WRN SD TONIGHT.
Bunkers
FXUS63 KABR 122015 sd
AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND NORTHEAST
SOUTH DAKOTA AND WEST CENTRAL MINNESOTA
NATIONAL WEATHER SERVICE ABERDEEN SD
315 PM CDT SUN SEP 12 1999
WINDS LATE THIS AFTERNOON GUSTING UP TO 40 MPH AT MBG AND PIR AS AN
AREA OF TIGHT SFC PRESSURE GRADIENT ROTATES SE THROUGH THIS AREA. THE
RUC SHOWS THIS WELL AND FORECASTS THE WINDS AT THE SFC TO BE SUSTAINED
AT 25 TO 30 KNOTS THROUGH EARLY EVENING. THEREFORE...WILL ISSUE A WIND
ADVISORY FOR C AND NC SD THROUGH 9 PM CDT. OTHERWISE...NGM AND ETA SHOW
BIG UPPER LOW REMAINING TO THE NE OF THE CWA AND WRAPPING ABUNDANT LL
MOISTURE OVER NE SD AND WC MN THROUGH THE FORECAST PERIOD. IN THE NEAR
TERM...RADAR AND SFC OBS SHOW LIGHT RAIN MOVING FROM NW TO SE FROM W ND
THROUGH NC AND NE SD AS WELL AS WC MN. THEREFORE...FOR TONIGHT ALL OF
THE CWA WILL BE MOSTLY CLOUDY TO CLOUDY WITH A CHANCE OF LIGHT RAIN.
BEST CHANCES WILL BE ACROSS N SD INTO WC MN. IT WILL BE WINDY ALL AREAS
THIS EVENING. TEMPERATURES SHOULD ONLY FALL OFF 5 TO 15 DEGREES FROM
THE 3 PM TEMPS. MDLS SHOW SOME DRYING IN C AND NC SD ON
MON...THEREFORE EXPECT THE SUN TO COME OUT. IT WILL ALSO BE BREEZY
ACROSS ALL OF THE AREA AND CONTINUED BELOW NORMAL TEMPS. WITH LITTLE
MOVEMENT OF UPPER LOW AND MOISTURE COMING AROUND ITS BACKSIDE...EXPECT
SKIES TO CLOUD UP AGAIN ACROSS C AND NC SD MONDAY NIGHT AND TUESDAY AS
THE REST OF THE AREA REMAINS CLOUDY. THE COOL AIR WILL ALSO STAY
AROUND. NO FAN GUID LATE THIS AFTERNOON. WENT GENERALLY HIGHER THAN FWC
ON POPS AND LOWER ON TEMPS.
...EXTENDED FORECAST DISCUSSION...
MRF CONTINUES TO BE THE MODEL OF CHOICE AS IT HAS BEEN THE MOST
CONSISTENT. THE NOGAPS IS A BIT SLOWER WITH SURFACE FEATURES AND THE
ECMWF IS CONSIDERABLY SLOWER...TO THE POINT OF WHERE IT ALMOST DOES
NOT LOOK LIKE THE SAME TIME FRAME. THE LARGE SURFACE HIGH WILL BE
SITUATED OVER THE NORTHERN PLAINS ON WEDNESDAY AND INTO THURSDAY
MORNING. THE HIGH BEGINS TO PUSH EAST THURSDAY AFTERNOON...MOVING TO
LOWER MICHIGAN BY 00Z FRI. H85 TEMPERATURES REMAIN COOL...BELOW
+10...ON WEDNESDAY AND THEN BEGIN A SLOW RECOVERY THURSDAY. LAYER RH
VALUES WILL BE LESS THAN 40 PERCENT...SO EXPECT PLENTY OF SUN. WILL
KEEP TEMPS COOL ON WEDNESDAY WITH SLIGHTLY HIGHER TEMPS
THURSDAY...AND SLIGHTLY HIGHER YET ON FRIDAY AS NEXT LOW PRESSURE
TROUGH PUSHES INTO THE WESTERN DAKOTAS AND SETS UP FAIRLY STRONG
WARM SOUTHERLY FLOW. BREEZY TO WINDY CONDITIONS LIKELY THURSDAY AND
FRIDAY. H85 TEMPS RISE TO BETWEEN +11 AND +20 ACROSS THE CWA ON
FRIDAY...BRINGING DAYTIME HIGHS BACK TO NEAR NORMAL VALUES.
.ABR...NONE
MOHR/PARKIN
FXUS63 KUNR 121906 sd
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1012 AM MDT SUN SEP 12 1999
BEST SFC PRES GRAD IS AND WILL REMAIN ACROSS NW SD TODAY. WITH CAA
NEARLY OVR IN ADVISED AREA...WILL HAVE TO RELY SOLELY ON SOLAR
HEATING FOR MIXING. LATEST RUC AND QUICK LOOK AT NEW ETA SHOW THAT
30-35 KT WNDS AVAILABLE IN H8 TO H7 LAYER PRIMARILY OVR THE PLAINS.
THE FURTHER SW YOU GO...THE LIGHTER THE WINDS. WINDS HAVE BEEN
RISING INTO ADVY CRITERIA ON PLAINS...BUT SLOW TO DO SO IN FOOT
HILLS. FEEL THAT FOOTHILLS WON'T QUITE MAKE ADVY CRITERIA...SO
PULLED HILITE FROM THAT ZONE. LOWERED POPS TO ISOLATED LIGHT SHRA
AND LEFT TEMPS ALONE.
WITH SFC HI SETTLING OVR THE CWA TONIGHT...WILL LIKELY HAVE TO GO
WITH FROST ADVY IN NE WY AND PARTS OF WRN SD TONIGHT WITH AFTERNOON
ISSUANCE.
.UNR...WIND ADISORY NW AND WC SD PLAINS TODAY
BAILEY
FXUS63 KFSD 121459 sd
TEXAS/OKLAHOMA PANHANDLES AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AMARILLO TX
718 PM CDT SUN SEP 12 1999
UPDATED ZNS TO REMOVE MENTION OF PRECIP AND ALTER SKY CONDITIONS.
LATEST SATELLITE IMAGERY SHOWS CLEARING ACROSS NEARLY ENTIRE FA
ATTM. 21Z RUC/12Z MODEL DATA SUGGEST WITH WEAK UPSLOPE FLOW LOW
CLOUDS WILL REDEVELOP BUT BE PRIMARILY LIMITED TO AREAS ON CAPROCK.
ISENTROPIC ANLYS SHOWS SOME WEAK LIFT ONGOING ACRS SE CO WHERE
CLOUDS STILL EVIDENT. PLACED METION OF PATCHY FOG IN NE ZNS WHERE
WELL OVER 1 INCH RAIN FELL LAST NIGHT...GOOD RADIATIONAL COOLING
SHOULD HELP GENERATE THAT. MAY NEED TO UPDATE SECOND PERIOD SKY
CONDITIONS LATER TO FOLLOW SUIT BUT WILL LOOK AT NEW MODEL RUNS
BEFORE MAKING ANY ADJUSTMENTS.
.AMA...
TX...NONE.
OK...NONE.
COBB
FXUS64 KFWD 122039 tx
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NATIONAL WEATHER SERVICE FORT WORTH TX
1235 PM CDT SUN SEP 12 1999
MODELS AGREE THAT FRONTAL PASSAGE OVER THE D/FW AIRPORTS SHOULD
OCCUR BETWEEN 12/23Z AND 13/03Z. WE'LL GO WITH LATEST RUC WHICH
SHOWED 01Z-02Z OVER D/FW...AROUND 05Z OVER WACO. TSRA/SHRA SHOULD
BE CONCENTRATED WITHIN 2 HOURS BEFORE AND AFTER FRONT. WIND GUSTS
COULD CREATE SOME PROBLEMS FOR AIRPORTS WHEN SQUALL LINE PASSES.
LOW CEILINGS SHOULD DOMINATE SKIES AFTER FRONTAL PASSAGE THROUGH
LATE AFTERNOON MONDAY. 64
===================================================================
1150 AM CDT SUN SEP 12 1999
THE 16Z SURFACE ANALYSIS AND SATELLITE IMAGERY INDICATE THAT THE COLD
FRONT THAT EXTENDS SOUTHEAST OF A WICHITA KANSAS...FREDERICK
OKLAHOMA...LUBBOCK LINE. THIS FRONT IS PROGGED TO CONTINUE ITS
SOUTHEAST PROGRESS THIS AFTERNOON AND TONIGHT...MOVING TO NEAR A
TEXARKANA...TO WACO LINE BY MIDNIGHT. SHOWERS AND THUNDERSTORMS
CONTINUE OVER SOUTHERN OKLAHOMA INTO THE NORTHWESTERN PART OF NORTH
TEXAS AT MIDDAY. WILL KEEP THE HIGHEST POPS ALONG THE RED RIVER
COUNTIES AND THE SECOND TIER BENEATH THEM THIS AFTERNOON. AS THE
FRONT MOVES FARTHER INTO NORTH TEXAS COVERAGE SHOULD INCREASE...SO
HAVE INCREASED POPS A TAD ACROSS THE CENTRAL AND EASTERN ZONES FOR
TONIGHT. #58
.FTW...NONE.
FXUS64 KFWD 121654 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
400 AM CDT SUN SEP 12 1999
TIME TO THROW PERSISTENCE OUT THE WINDOW FOR A CHANGE. A STRONG COLD
FRONT IS CURRENTLY SURGING SOUTHWARD THROUGH THE CENTRAL PLAINS AND
STRETCHES ACROSS THE NORTHWESTERN HALF OF KS INTO SOUTHEASTERN CO.
AT 06Z...3 HOUR PRESSURE RISES WERE NOTED IN THE 4-6MB RANGE BEHIND
THE BOUNDARY. LATEST RUC DATA SUPPORTS 00Z ETA MODEL IN BRINGING THE
FRONT INTO THE SOUTHERN PANHANDLE BY MID MORNING AND THROUGH THE
SOUTHERN PORTION OF THE CWFA BY EARLY THIS AFTERNOON. EXPECT A WIND
SHIFT WELL AHEAD OF FROPA AS PRE-FRONTAL TROUGH ASSOCIATED WITH A
WEAK AREA OF LOW PRESSURE ANALYZED OVER THE SOUTHERN PANHANDLE AT
06Z MOVES INTO THE REGION.
FIRST INSTINCT WAS TO TREND TODAY'S TEMPERATURES TOWARD THE NGM WITH
RATHER MILD CONDITIONS EVIDENT ATTM AND THE ANTICIPATED SEVERAL
HOURS OF HEATING UNTIL FROPA. WIDESPREAD LOW CLOUDS DEVELOPING
SOUTHWARD THROUGH THE PANHANDLE WILL LIKELY AFFECT AT LEAST THE
NORTHERN TWO TIERS OF COUNTIES PRIOR TO FROPA SO WILL HAVE TO ADJUST
THINKING FOR THAT SCENARIO. CLOUDS SHOULD FILL IN THE REMAINDER OF
THE CWFA AFTER FROPA AND WILL LIKELY CONTINUE THROUGH TONIGHT. FRONT
AND ASSOCIATED CAA APPEARS STRONG ENOUGH THAT TEMPERATURES SHOULD
HOLD STEADY OR SLOWLY FALL THIS AFTERNOON AFTER REACHING MAX VALUES
SOMETIME THIS MORNING/EARLY THIS AFTERNOON. WILL HOIST THE FLAGS FOR
ANTICIPATED WINDS INCREASING TO LAKE CAUTION CRITERION AFTER FROPA.
ISENTROPIC LIFT OVER FRONTAL BOUNDARY AND AVAILABLE MOISTURE AND
INSTABILITY SHOULD RESULT IN SCATTERED CONVECTION TODAY AND HAVE
GONE ABOVE MACHINE NUMBERS. ISENTROPIC DOWNGLIDE IS PROGGED TO
DEVELOP OVER MUCH OF THE CWFA TONIGHT BY THE ETA MODEL AS THE FRONT
SURGES WELL SOUTH OF OUR AREA. CONTINUED SLIGHT CHANCE POPS INTO
TONIGHT THEN ENDED THE CHANCES OF RAIN AS REGION OF ISENTROPIC
UPGLIDE SHIFTS WELL WEST OF SOUTHWEST OF US. COULD CONTINUE TO BE
PERIODS OF LOW CLOUDS AND MAYBE EVEN SOME DRIZZLE BUT DON'T BELIEVE
THE CHANCE OF MEASURABLE RAIN IS HIGH ENOUGH AFTER TONIGHT TO
WARRANT MENTION IN THE FORECAST.
SHORT WAVE RIDGING DEVELOPS AND CONTINUES OVER THE SOUTHERN PLAINS
INTO THE EXTENDED PERIOD. THIS SHOULD DELAY THE NEXT OPPORTUNITY
FOR RAIN UNTIL MID WEEK WHEN ISENTROPIC LIFT REDEVELOPS OVER THE
STATIONARY FRONT/NORTHWARD RETURNING WARM FRONT WITH THE APPROACH OF
A SHORT WAVE TROUGH.
FRIONA 80/53/71/51 3211
TULIA 81/54/72/52 3211
CHILDRESS 82/55/73/54 5211
BROWNFIELD 88/57/76/54 4211
LUBBOCK 86/55/74/53 4211
ASPERMONT 89/58/77/56 5211
.LBB...NONE.
EJC
FXUS64 KFWD 120858 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
850 PM EDT SUN SEP 12 1999
SFC RIDGE AXIS EXTENDING SWD THRU ERN VA PROVIDING ANOTHER QUIET WX
EVE ACROSS THE AREA TNGT. APCHG PREFRONTAL SFC TROF COMBO WITH WEAK
RETURN WAA ALF PUSHING SOME MID/HIGH CLDNS TWD THE WRN ZONES PER IR
PICS OTRW DRY AIR CONTS IN PLACE. WITH THE LATEST RUC INDICATING
MOST OF THIS RH REMAINING NORTH/WEST...AND GIVEN DRYNESS OFF EVE
RAOBS SHOULD BE ABLE TO CONT GOING MSTLY CLEAR FCST OVRNGT. OTRW
TEMPS ABOUT THE ONLY CONCERN WITH BETTER RAD CONDS IN PLACE. DEWPTS
SUGGEST LOWS TNGT CLOSE TO THOSE OF THIS MORN ALTHO SCT CLDNS WEST
AND LGT MIXING RDGS SHOULD ALLOW A BIT MORE RANGE BY MORN.
.RNK
VA...NONE.
WV...NONE.
NC...NONE.
JH
FXUS61 KAKQ 130049 va
EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
255 AM PDT MON SEP 13 1999
A WEAK UPPER LOW OFF THE CENTRAL CALIFORNIA COAST WILL MOVE SLOWLY
INLAND INTO CENTRAL CALIFORNIA TODAY AND TUESDAY WITH A SLIGHT
INCREASE IN ONSHORE LOW LEVEL FLOW FOR SOUTHERN CALIFORNIA.
TEMPERATURES FOR TODAY AND TUESDAY WILL COOL SLOWLY ALONG THE COAST
WITH LITTLE CHANGE INLAND. A MINOR INTRUSION OF MID LEVEL MONSOONAL
MOISTURE WILL BRING A CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS
TO THE MOUNTAINS AND DESERTS TODAY WITH SOME DRYING FOR TUESDAY.
BLOCKING PATTERN CONTINUES ALG THE W CST OF NOAM WIH A HIGH
AMPLITUDE RDG ALG THE CST OF BRITISH COLUMBIA AND THE PAC NW WITH A
WK UPR LOW TO THE S...OFF THE CNTRL CA CST. STRONG WESTERLIES N OF
40N ACROSS THE WRN AND CNTRL PAC WL IMPACT THIS BLOCK WITH THE BLOCK
PROGESSING SLOWLY INLAND ALG THE W CST TODAY AND TUE WITH THE WK UPR
LOW OFF THE CNTRL CA CST MOVG SLOWLY INLAND INTO CNTRL CA TODAY AND
TUE. IMPACTS WL BE SLIGHT IN SRN CA WITH A MINOR INCR IN LOW LVL
ONSHR FLOW...MORE SO IN THE FORM OF A DECR IN OFSHR TRENDS AT NIGHT
THAN FM AN INCR IN THE ONSHR FLOW IN THE AFTERNOON. SOME DRYING OF A
MINOR INTRUSION OF MID LVL MONSOONAL MSTR SHOULD ALSO BEGIN TUE.
AVN/ETA/NGM WIDELY DIVERGENT IN THEIR TRENDS WITH THIS MID LVL MSTR
WITH ETA PREFERRED IN SHOWING ONLY A GRADUAL DRYING FOR TUE. WL ADD
SLIGHT CHANCE OF AFTERNOON/EVENING THUNDERSTORMS TO MTNS/DESERTS
TODAY AS RUC/MAPS HAS QPF ALG N/S RANGES BETWEEN 21Z/00Z TODAY FM
THE SBD MTNS S. ETA SHOWS LTL CHANGE IN PW'S ACROSS SRN CA THRU TUE
WITH A SHARP GRADIENT ACROSS NRN SXNS OF SRN CA BETWEEN HIGHER
VALUES TO THE SE AND LWR VALUES TO THE NW. WITH MONSOONAL MSTR
CONTINUING TO LINGER INTO TUE...CAN'T RULE OUT THE POSSIBILITY OF A
FEW THUNDERSTORMS FOR THE MTNS/DESERTS DURG PK HEATING...BUT WL NOT
INTRODUCE AT THIS TIME.
EXTENDED...MDLS DIFFER SOMEWHAT OVR THE WEST...BUT GENERALLY
MAINTAIN A WK UPR TROUGH OVR CA...SUFFICIENT TO PREVENT A
SIGNIFICANT INFLUX OF MONSOONAL MSTR INTO SRN CA...BUT INSUFFICIENT
TO ALLOW MID LVL MONSOONAL MSTR TO COMPLETELY EXIT THE ERN DESERTS
OF SRN CA. IN GENERAL...LTL CHANGE FM THE PRESENT WITH SEASONAL
TEMPERATURES INLAND AND SLIGHTLY BELOW NORMAL TEMPERATURES NR THE
CST DUE TO LWR THAN NORMAL SST'S OVR THE ADJ CSTL WTRS.
FOR THE LATEST UPDATES ON HURRICANE "FLOYD"...PLEASE REFER TO THE
LATEST NHC ADVISORIES AT HTTP://WWW.NHC.NOAA.GOV/INDEX_SPECIAL.HTML
SAN 000
.SAN...NONE.
MARTIN
FXUS66 KHNX 130951 ca
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY-RUSKIN, FL
255 AM EDT MON SEP 13 1999
06Z SURFACE ANALYSIS CONTINUED GENERAL SYNOPTIC PATTERN OF THE LAST
48 HOURS WITH HIGH PRESSURE CENTERED OVER THE CAROLINAS WITH A WEAK
RIDGE AXIS THAT EXTENDED SOUTHWEST INTO THE FLA PANHANDLE. WEAK LOW
PRESSURE TROUGH REMAINED OVER THE EASTERN GULF OF MEXICO SOUTHEAST
TO THE FLORIDA KEYS. LAPS 06Z ANALYSIS INDICATED SURFACE MOISTURE
CONVERGENCE OVER CENTRAL FLORIDA WHICH HAS SHOWED UP ON RADAR AS AN
EXPANDING EAST TO WEST BAND OF PRECIPITATION.
O0Z MID LEVEL ANALYSIS INDICATED HIGH PRESSURE RIDGE THAT EXTENDED
FROM BERMUDA WEST SOUTHWEST TOWARD NORTH FLORIDA WITH ELONGATED EAST
TO WEST VORTICITY MAXIMUM OVER NORTH CENTRAL FLA. 300 MB ANALYSIS
PAINTED HIGH PRESSURE NORTHEAST OF THE BAHAMAS WITH RIDGE SOUTHWEST
TO THE KEYS.
00Z FLA SKEW-T ANALYSIS INDICATED NORTHEAST FLOW ENTRENCHED FROM
SURFACE TO 15K WITH SOUTHWEST FLOW FROM 25-40K. PRECIPITABLE WATER
LEVELS RANGED FROM 1.7 TO 2.1 ACROSS WEST CENTRAL FLORIDA WITH
MARGINALLY UNSTABLE UPSTREAM ATMOSPHERE.
MODEL ANALYSIS OF ETA...NGM...AVN AND RUC INDICATED THAT AFTER A
QUICK SHOT OF PRECIP THIS MORNING AND EARLY AFTERNOON ACROSS WEST
CENTRAL AND SOUTHWEST FLORIDA...NEGATIVE VORTICITY AND CORRESPONDING
WEAK SUBSIDENCE MOVES OVER FORECAST AREA LATE AFTERNOON THROUGH
TONIGHT. THUS ZONES WILL REFLECT MAINLY SCATTERED MORNING AND EARLY
PM SHOWERS AND THUNDERSTORMS ACROSS FORECAST AREA DIMINISHING LATE.
AS MODEL GRADIENT INCREASES BETWEEN SURFACE RIDGE TO OUR NORTH AND
HURRICANE FLOYD...EXPECT SUSTAINED WINDS TO REACH CLOSE TO THE
"BREEZY" CATEGORY TODAY AND WILL WORD FOR "WINDY" ON TUESDAY ACROSS
FORECAST AREA.
ZALESKI
FXUS62 KTAE 130637 fl
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
227 PM MDT SUN SEP 12 1999
ATTM SFC HIGH PRESSURE WAS CONTINUING ITS MOVEMENT INTO THE CENTRAL
PLAINS. STRONG MID LVL LOW CONTS OVR THE UPPER MISSISSIPPI VALLEY
KEEPING PRESSURE GRADIENTS TIGHT ACRS THE TRI-STATE AREA. LOW/MID LVL
CLOUD COVER WAS PERSISTING OVR THE SOUTHERN HALF OF THE CWA AS COLD
AIR CONTS TO ADVT INTO ALL OF THE FA. ETA SEEMED TO BE ON A BETTER
TRACK THAN THE NGM WITH THE DIMINISHING CLOUD COVER ACRS THE AREA.
SFC WINDS BECOME NNE AND DECOUPLE ACRS THE WESTERN FA TONIGHT
PRODUCING A SLIGHT UPSLOPE WHICH MAY KEEP/DEVELOP THE LOW/MID LVL
CLOUD COVR OVER THIS AREA. ALSO AS WARM AIR ADVTS ACRS THE MID LVLS
WITH COOLR AIR AT THE SFC THE POTENTIAL FOR DEVELOPING CLOUDS AGAIN
IS POSSIBLE OVR THE W FA. IF THIS OCCURS...AS THE MODELS INDICATE...
OVERNITE LOWS SHUD REMAIN ABOVE FREEZING SO THE CONCERN FOR FROST
SHUD BE MINIMAL. BUT...THE LATEST SATELLITE SHOWED CLOUD COVER
DECREASING AND THE RUC INDICATED THIS ALSO INTO TONIGHT. IF THIS
HAPPENS...THE POSSIBILITY OF FROST INCREASES BUT AFTER VIEWING THE
LAMP DATA...AGREE THAT SFC TMPS/DEW POINTS SHUD REMAIN ABOVE FREEZING
REGARDLESS OF CLOUD COVER.
THE MID LVL LOW WILL DRIFT EAST AND WITH THE SLOW INCREASE IN
5H/HGHTS AND THCKNS...ANOTHER BELOW AVE TEMPERATURE DAY IS LIKELY
TOMORROW. THE POSSIBLE CLOUD COVER OVR THE WESTERN FA DRIFTS INTO THE
CENTRAL AND EASTERN CWA MONDAY AND SHUD HOLD TOGETHER AS MID LVL WARM
AIR CONTS TO ADVT OVR THE COOL LOWR LVL TMPS BUT AS IT DOES...IT
SHUD SLOWLY ERODE THEREFORE WILL GO WITH PARTLY CLOUDY SKIES.
ANOTHER COOL MONDAY NITE IS IN STORE FOR THE FA WITH A SLIGHT WARM
UP TUESDAY. SFC WINDS VEER INTO THE SOUTH AND MID LVL MOISTR
INCREASES. AFTN CLOUDS SHUD DEVELOP AND WITH AN APPROACHING 5H/VORT
MAX FROM THE WEST...A FEW TSRA MAY DEVELOP LATE IN THE AFTN AND
POSSIBLY INTO THE EVENING.
FOR THE EXTENDED A STRONGER 5H/DISTURBANCE MOVES INTO THE CENTRAL
PLAINS WEDNESDAY AND WITH MID LVL MOISTR PERSISTING THE CHANCES OF
TSRA WILL INCREASE FOR THE CWA. THIS DISTURBANCE APPEARS SLOW TO
MOVE THEREFORE WILL KEEP POPS IN THE FORECAST THURSDAY. BY THE END
OF THE WEEK 5H/HI PRESSURE BUILDS INTO THE AREA AND AFTN TMPS SHUD
WARM WITH DIMINISHING POPS.
.GLD...NONE.
VPAPOL
FXUS63 KICT 121959 ks
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
425 AM EDT MON SEP 13 1999
MAIN FCST CHALLENGE IS PRECIP ASSOCIATED WITH BROAD UPPER LOW.
WV IMAGERY THIS MORNING SHOWS BROAD UPPER LEVEL LOW...WITH
CIRCULATION CENTER JUST TO THE WEST OF THE UP. 11-3.9 IMAGERY SHOWS
DRY SLOT OVER WEST AND CENTRAL UP AND MUCH OF LAKE SUPERIOR AT 05Z.
MODELS IN PRETTY GOOD AGREEMENT IN LIFTING THIS LOW SLOWLY
NORTHEASTWARD TO JUST NORTH OF LAKE SUPERIOR AT 00Z TUE...AND
NORTHEAST ONTARIO AT 00Z WED. NOT SURPRISINGLY...SOME DIFFERENCES IN
HOW THE MODELS HANDLE SHORTWAVES EMBEDDED IN THE CLOSED LOW.
NGM A LITTLE WETTER THAN ETA...ESPECIALLY TODAY WHEN ETA KEEPS ALL
BUT WESTERN CWA DRY UNTIL LATE. MOS POPS ALSO RUNNING HIGHER
THAN THE 12Z MOS. NGM SHOWS LIGHT PRECIP TO A MQT-IMT LINE BY 18Z
TODAY AND NEAR ERY BY 00Z TONIGHT. THE NGM DID NOT INITIALIZE THE
SHORTWAVES VERY WELL...SO I DO NOT HAVE MUCH CONFIDENCE IN IT. RUC
AND MESOETA DO OK JOB OF IDENTIFYING THE SHORTWAVES NORTH OF LAKE
SUPERIOR AND ENTERING NORTHERN WISCONSIN. THEY ALSO HAVE A PRETTY
GOOD HANDLE ON STRENGTH AND POSITION OF SURFACE LOW CENTERED NORTH
OF LAKE SUPERIOR.
TODAY...FA UNDER AREA OF WEAK 700-300MB Q-VEC DIVERGENCE BEHIND
EXITING SHORTWAVES. 1000-500MB RH INCREASES DURING THE DAY. ETA DOES
SLIGHTLY BETTER HANDLING SFC FEATURES AT 6Z MON...SO WILL LEAN
TOWARDS ITS SLIGHTLY DRIER PATTERN. WILL MAINTAIN CONTINUITY WITH
PREVIOUS FORECAST...BUT ADD CHANCE OF AFTERNOON SHOWERS. AFTER
COORDINATING WITH GRB AND APN...WILL ADD LOW CHANCE POPS IN
WISCONSIN BORDER COUNTIES AND IN THE EASTERN COUNTIES.
TONIGHT AND TUESDAY...NO MAJOR CHANGES IN CIRCULATION. UPPER LOW
LIFTS SLOWLY NORTHEAST. CYCLONIC FLOW CONTINUES WITH A SLIGHT
INCREASE IN SFC CONVERGENCE. 1000-500MB RH REMAINS AOA 70 PERCENT
OVER THE UP...WITH 1000-850MB RH IN THE 80-90 PERCENT RANGE. MESOETA
SHOWS AREA OF QVEC CONVERGENCE MOVING INTO WESTERN COUNTIES...WITH
MEASURABLE PRECIP FROM KEWEENAW STRETCHING SOUTHWEST BY 00Z. THIS
TREND SHOULD CONTINUE THROUGH THE EASTERN COUNTIES AS THE SHORTWAVE
MOVES AROUND THE UPPER LOW.
TUESDAY NIGHT...LATEST AVN MAINTAINS HIGH RH OVER CWA. AVN ALSO
GENERATES LIGHT PRECIP OVER THE UP AS 500MB TROF CROSS THE FA
OVERNIGHT. THIS SEEMS IN LINE WITH THE 48 HOUR FORECASTS OF THE
NGM/ETA. FOR NOW WILL JUST KEEP THINGS MOSTLY CLOUDY WITH SCATTERED
SHOWERS EARLY.
COORD WITH GRB...APN.
.MQT...NONE.
JS
FXUS63 KAPX 130759 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
358 AM EDT MON SEP 13 1999
COLD FRONT AND BACK EDGE OF PRECIPITATION HAVE REACHED I-75 AS OF 0745Z
AND CONTINUE TO SHOW STEADY PROGRESS EAST. IR LOOPS SHOW CLEARING
FOLLOWING QUICKLY ON THE HEELS OF THE FRONT...BACK EDGE OF CLOUD DECK
HAS REACHED LAKE MICHIGAN SHORE SOUTH OF THE LEELANAU PENINSULA.
CURRENT TIMING SHOULD SEE RAIN PUSH OFF THE LAKE HURON SHORELINE BY
13Z...FOLLOWED QUICKLY BY CLEARING. MAIN PROBLEM UPCOMING THEN DEALS
WITH RESIDUAL WEATHER PROVIDED BY UPPER LOW OVER SOUTHWEST ONTARIO...
INCLUDING DIURNAL/LAKE EFFECT RAIN SHOWERS.
MODELS CONTINUE TO BE CONSISTENT IN GRADUALLY LIFTING UPPER LOW A LITTLE
FARTHER NORTHEAST...THEN BEGIN TO OPEN UP THE SYSTEM TOWARD THE END OF
THE FORECAST PERIOD. DRY SLOT EVIDENT IN WV IMAGERY BEHIND VORTICITY
LOBE WILL PUSH ACROSS THE AREA THIS MORNING...WITH MOST AREAS SEEING A
FAIR AMOUNT OF SUNSHINE TO START THE DAY. CU SHOULD DEVELOP QUICKLY AS
LOW LEVEL CAA CONTINUES (ALREADY OCCURRING PER MODEL PROGS AND EVIDENT
IN BACKING LOW LEVEL WIND PROFILE IN KAPX VWP). ETA AND 06Z RUC
CONTINUES TREND OF SHOWING A SMALL (500-600 J/KG) BUT NARROW CAPE THIS
AFTERNOON AS LAPSE RATES WILL BE FAIRLY STEEP...SO MENTION OF SCATTERED
AFTERNOON SHOWERS ALL AREAS STILL LOOKS REASONABLE. SHOULD BE FAIRLY
BREEZY AFTERNOON WITH WIND AOB 850MB APPROACHING 30KTS.
TONIGHT...ETA ENDS UP IN-BETWEEN WARMER NGM AND COLDER AVN WITH 850MB
TEMPERATURES IN THE 3-4C RANGE...YIELDING DELTA-T'S OF 16-18C. THE
COMBINATION OF INSTABILITY AND INCREASING LOW LEVEL RH SHOULD LEAD TO A
GOOD DEAL OF LAKE SC...AND WITH PREVAILING SOUTHWEST FLOW WILL CONTINUE
MENTION OF SOME SHOWERS COMING IN OFF OF LAKE MICHIGAN FOR COUNTIES
WEST OF I-75...BEST CHANCE NORTH OF M-72 WHERE SOUTHWEST FETCH A LITTLE
LONGER. EAST OF I-75...WILL JUST WORD FORECAST AS PARTLY CLOUDY.
TEMPERATURES WILL BE A BIT TRICKY DEPENDING UPON PROXIMITY TO LAKE
MICHIGAN AND CLOUD COVER...GENERALLY WENT ABOVE FWC NUMBERS. FOR
TUESDAY...COMBINATION OF WRAP AROUND CLOUDS ADVECTING IN PLUS LAKE/
DIURNAL COMPONENTS SHOULD RESULT IN A MOSTLY CLOUDY DAY...AND CONTINUED
SMALL CHANCE POPS PER GOING FORECAST. TUESDAY LIKELY TO BE ANOTHER
GOOD WATERSPOUT DAY AS WELL.
COORDINATED WITH MQT.
.APX...NONE.
JPB
FXUS63 KGRR 130738 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
945 PM EDT SUN SEP 12 1999
LARGE UPPER LO OVER N MN IS DOMINATING THE WX IN THE U.P. WITH THE
SFC LO OCCLUDING JUST NORTH OF LS. DRY AIR HAS WORKED IN FROM THE
SOUTH INTO THE U.P THIS EVENING ALLOWING FOR MAINLY DRY CONDITIONS.
BUT THERE ARE EXCEPTIONS. THE OCCLUSION HAS SPARKED SOME FAIRLY
POTENT TSTMS OVER EASTERN LS WHERE THERE IS A LITTLE CAPE. THESE
STORMS ARE HEADING NE AT 30 KTS AND SHOULD BE OUT OF THE CWA BY
MIDNIGHT.
THE 21Z RUC SHOWS A PV LOBE SPINNING AROUND THE UL LOW OVER WESTERN
LS AT 00Z. THE LIFT ASSOCIATED WITH THE PVA IS HELPING TO SUSTAIN A
LINE OF MOSTLY SHRA /SOME THUNDER/ MOVING EAST. WINDS HAVE BEEN
CLOSE TO 30 MPH WITH THE LINE SO WILL INSERT A GUSTY SHOWER IN THE
CENTRAL COUNTIES OVERNIGHT. THE RUC ALSO SHOWS ANOTHER SHRTWV OVER
CENTRAL MN AT 00Z. THIS LINES UP WELL WITH SHRA NW OF MSP. THE
SHRTWV IS PROGGED TO BE NEAR IWD BY 09Z...SO WILL LEAVE IN THE
MENTION OF A SHOWER WEST.
A DAY MUCH LIKE LAST THURSDAY ON TAP FOR TOMORROW WITH INSTABILITY
SHRA WORKING IN FROM THE WEST DURING THE AFTERNOON.
.MQT...NONE.
ALTOE
FXUS63 KDTX 130149 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
250 AM CDT MON SEP 13 1999
TEMPS WILL BE THE MAIN FCST CONCERN THRU TUE. LATEST SFC ANLYS EARLY
THIS MORNING SHOWED RIDGE OF HIGH PRES FROM CNTRL MT-ERN CO-TX PNHDL.
PRES GRADIENT WAS STILL FAIRLY TIGHT OVER THE FCST AREA. MAIN AREA
OF LOW CLOUDS IS STILL TO THE NORTH...BUT EXPECT ADDITIONAL DVLPMT
WITH HEATING TODAY. TEMPS SUN WERE A BIT WARMER THAN EXPECTED...BUT
CAA WILL CONT AT LEAST THRU 15Z ACCORDING TO RUC MODEL. SOME WAA
SHOULD DVLP BY LATE AFTN...BUT THAT MAY BE TOO LATE TO HAVE MUCH OF
AN IMPACT ON TEMPS. HIGHS SHOULD RANGE FROM 60-65 NEAR TQE TO ABOUT
70 NEAR KS BORDER. ETA MODEL 850 MB RH FCST SEEMS REASONABLE...
BRINGING BKN CLOUDS BTWN ABOUT 3000-6000 FT TO PARTS OF NERN NE AND
WRN IA BY AFTN. CAN NOT TOTALLY RULE OUT A FEW SPRINKLES IN THE AREA
WITH HIGHEST RH AND CYCLONIC FLOW...BUT WILL PROBABLY NOT MENTION AT
THIS TIME. CURRENT LOW LEVEL WINDS ON NELIGH PROFILER ARE LIKELY
TOO HIGH...COULD BE SOME AFFECTS OF SONGBIRD MIGRATION. STILL...
WINDS WERE ABOUT 20 TO 30 KTS BEFORE SUNSET AND IN AGREEMENT WITH
00Z OAX SOUNDING. WILL CONT BREEZY WORDING FOR TODAY.
THERE MIGHT BE A FEW CLOUDS LINGERING IN NRN PART OF NERN NE TNGT...
BUT THE REST OF FCST AREA SHOULD CLEAR OUT. SFC WINDS WILL DECOUPLE
QUICKLY THIS EVENING AS INVERSION SETS UP. LOWS FROM THE PREVIOUS
FCST LOOK GOOD. MIGHT DROP THESE SLIGHTLY FOR NWRN CORNER OF FCST
AREA AN GO WITH MID TO UPPER 30S. NO MENTION OF FROST FOR NOW.
EXPECT CU/SC TO INCREASE AGAIN ON TUE. 850 MB AND 1000-500 MB THKNS
VALUES CHANGE LITTLE ON TUE...COMPARED TO TODAY...SO WILL KEEP TEMPS
ABOUT THE SAME. WILL LEAVE FCST DRY TUE NGT...BUT COULD SEE SOME
ELEVATED SHOWERS IN PARTS OF SERN NE WITH ISENTROPIC LIFT IF ETA AND
AVN ARE CORRECT. HAVE NO PLANS TO MAKE CHANGES TO 3-5 DAY FCST.
FIRST DRAFT OF WORK ZONES WAS ALREADY SENT.
.OMA...NONE
MILLER
FXUS63 KLBF 130728 ne
FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
1015 AM CDT SUN SEP 12 1999
UPDATE PLANNED. WELL DEVELOPED EXTRATROPICAL CYCLONE OVR NRN PLAINS.
SFC LOW INTO NERN WI WHILE UPR LOW APPRS JUST NORTH OF DVL. DRY SLOT
EXTENDING WELL INTO SRN MAN...WHILE COMMA HEAD CLOUDS WRAPPING
RAPIDLY AROUND UPR LOW THROUGH WRN ND. CLOUD FREE AREAS OF SERN ND
AND WCNTRL MN LIKELY TO FILL IN AS CLOUDS ADVECT IN AND MID LVLS
COOL. MAX TEMPS MAY EDGE INTO LOW 60S THERE BEFORE OVRCST MOVES IN.
SHOWERY CONDITIONS FROM NCNTRL ND TO SPREAD/DVLP EWD AHEAD OF VORT
MAX IN COMMA HEAD. RRV ZONES TO REMAIN DRY THROUGH EARLY AFTERNOON
...THEN FILL IN WITH WIDESPREAD CONVECTIVE PRECIP UNDER COMMA HEAD.
IN NRN MN...ENHANCED SHOWERS MOVING THROUGH BDE THROUGH AM WITH HARD
BACK EDGE OF VORT LOBE SHOWING IN VIS IMAGERY EAST OF ROX-AIT LINE.
PRECIP AMOUNTS SHOULD RANGE UPWARD OF A HALF INCH ACROSS NRN ZONES
TDY AND TNGT WITH 00Z ETA AND 06Z RUC DRAWING HEAVIEST AMOUNTS
THROUGH THERE. SRN ZONES WILL HAVE SPOTTIER PRECIP TDY AND TNGT WITH
MORE CONVECTIVE ELEMENTS....AND PRECIP AMOUNTS RANGING FROM A FEW
HUNDRETHS TO A HALF INCH OR SO.
.FGF...NONE.
GUST
nd
CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
910 PM EDT SUN SEP 12 1999
INTERESTING VORT MAX WENT BY AT HI LVLS THIS AFTN WITH SOME CB TOPS
DEVELOPING WITH BASES ABOVE 15KFT. NO PRECIP ANYWHERE BUT LOTS OF
SNOW VIRGA COMING OUT OF CB TOPS. RUC SHOWED THIS NICELY. WHAT IS
LEFT OF THIS HI LVL CONVECTION IS UP OVR SW NEW ENG.
24 HR TEMPS 4 TO 8F WARMER THAN YDY AT THIS TIME. ERI IS 14F
WARMER. AFTN TEMPS REACHED THE LOW 90S OVR OH IN SW FLO JUST AHEAD
OF APROACHING CFRNT. MODELS DO NOT BRING THAT AIR E OF MTNS AT THE
SFC OR AT 85H. WITH THE SFC HI TO THE NE OF OUR BEAUTIFUL STATE
THERE COULD BE A CASE MADE FOR A COOL AIR DAM...IF THERE WERE CLDS
TO HOLD TEMPS DOWN. FWC TMPS RAN 3F TOO COOL TDY AT MDT AND WILL
PROB BE ABOUT THE SAME TOM. SUBSTANTIAL CLD WILL NOT REACH LWR SUSQ
TIL MID TO LATE AFTN AND THIS WILL ALLOW FULL INSOLATION. WITH RISK
OF A BIG BUST ON THE WARM SIDE WILL BUMP TEMPS UP JUST A BIT FOR MON.
OTHW NO CHANGES.
EUROPEAN HAS BEEN MOST CONSISTANT WITH EVENT THIS COMING WEEK. OTHER
MODELS ARE BACKING OFF A LANDFALL BUT HAVE BEEN INCONSISTANT. AS
USUAL...WE MUST WAIT AND SEE.
.CTP...NONE.
HEAD
FXUS61 KPBZ 121857 pa
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
126 AM EDT MON SEP 13 1999
CLOSED LOW IN CENTRAL CANADA TO PROGRESS LITTLE. RUC SHOWS WEAK
ADVECTION VORT LOBE LEAVING AREA THIS MORNING. WEAK UPPER ENERGY
TO BE CHANNELED NE ALONG MOUNTAINS THEREAFTER. SURFACE COLD FRONT
REACHES TN SIDE OF MOUNTAINS LATE TON...THEN STALLS. SURFACE RIDGE
TO PERSIST E OF MOUNTAINS WITH NE WINDS. MODELS HAVE BACKED OFF
AGAIN ON MOISTURE INCREASE...WITH NGM AGAIN MORE AGRESSIVE AT
LOW AND HIGH LEVELS. WILL INCREASE CLOUDS NC MOUNTAINS AS MOISTURE
ASSOCIATED WITH FRONT ARRIVES. SOME MODIFICATION OF AIR MASS TO
BRING DEW POINTS AND MINIMUMS TEMPERTURES UP...WHILE NE WIND AND
EVENTUAL CLOUD COVER KEEP MAXIMUMS FROM RISING. FWC NUMBERS HAVE
BEEN GOOD LATELY AND WIL GENERALLY BE FOLLOWED. FAN TOO COOL...AND
TOO WET TUE.
AVL 81/55/78 000
CLT 83/58/82 000
GSP 84/59/83 000
.GSP...NONE.
JAT
FXUS62 KCHS 130110 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EL PASO TX/SANTA TERESA NM
223 AM MDT MON SEP 13 1999
SYNOPSIS...
A COOL FRONT FROM THE EAST PLAINS PUSHED THROUGH OUR REGION
OVERNIGHT PRODUCING GUSTY EAST WINDS...ISOLATED THUNDERSTORMS...
AND WIDELY SCATTERED SHOWERS INCLUDING LAS CRUCES AND EAST EL PASO.
THE COOL EAST WINDS WILL CONTINUE TODAY WITH DAYTIME TEMPERATURES
SOME 5 TO 10 DEGREES COOLER THAN SUNDAY. TONIGHTS THE WINDS WILL
BEGIN TO VEER TO SOUTHEAST AND DIMINISH AS THE BRUNT OF THE COLD
HEADS SOUTH OF THE BORDER. TEMPERATURES WILL SLOWLY RECOVER TUESDAY
AND WEDNESDAY AS HIGH PRESSURE ALOFT REBUILDS OVER THE LAND OF
ENCHANTMENT.
DISCUSSION...
FRONT PASSING AS PROGGED AND PRODUCING TSRA AS PROMISED BY THE NGM.
0.2 INCH RECORDED IN LRU JUST AFTER MIDNIGHT AND SACRAMENTO MTN
TOWERS/11-4 IR SATELLITE SHOWING FOG/LOW CLDS/-RA IN UPSLOPE THERE.
06Z SFC ANAL SHOWS 11MB AMA-ELP DIFFERENCE DIMINISHING TO ABOUT 6MB
BY 00Z AND 4MB BY 12Z TUE. WINDS WILL VEER TO SE THIS EVENING SO
WILL LOSE THE UPSLOPE SACRAMENTO CLOUDS/PRECIP THIS AFTERNOON/EARLY
EVENING. COLDEST BACKDOOR AIR HEADING SOUTH OF THE BORDER. AS SFC
WINDS VEER TO SE...EXPECT SOME UPSLOPE FORCING FOR THE SOUTHERN GILA
THIS AFTERNOON/EVENING AND WILL UP POPS THERE. WILL KEEP FCST TEMPS
BELOW GUIDANCE ALSO WITH LAMP AND COLD-BIASED RUC COOLER THAN MOS.
COOL NIGHT TUE AS THE SFC GRADIENT RELAXES SOMEWHAT. THEN RECOVERY
BEGINS TUE-WED AS UPPER HIGH RETURNS. SAME OLD TIRED LOW-GRADE
MAX-HEATING POPS LOOKS REASONABLE BUT WITH WESTERLIES WORKING SOUTH
TOWARD THE END OF THE WORK WEEK.
EL PASO BB 84/ 58/ 86/ 61/ 88 21112
LAS CRUCES BB 84/ 56/ 84/ 58/ 86 21112
ALAMOGORDO BB 82/ 55/ 84/ 57/ 86 21112
CLOUDCROFT CB 63/ 39/ 67/ 40/ 69 41112
TRUTH OR CONSEQUENCES BB 82/ 56/ 84/ 58/ 86 21112
SILVER CITY BB 82/ 47/ 82/ 50/ 84 23222
DEMING BB 84/ 55/ 85/ 56/ 87 22112
LORDSBURG BB 87/ 59/ 87/ 57/ 89 22112
.ELP...NONE
06 RAMEY
N
FXUS64 KHGX 130818 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAMPA BAY-RUSKIN, FL
925 AM EDT MON SEP 13 1999
MORNING SURFACE ANALYSIS PLACES HIGH PRESSURE OVER THE MID ATLANTIC
COAST WITH SURFACE RIDGE AXIS EXTENDING SOUTHWEST TO THE WESTERN FL
PANHANDLE. NORTHEASTERLY GRADIENT BEGINNING TO TIGHTEN ACROSS THE
FORECAST AREA...SO WEST COAST SEA BREEZE SHOULD NOT BE A PLAYER IN
TODAYS WEATHER. REVIEW OF MORNING KTBW SOUNDING REVEALS PWATS JUST
OVER 2 INCHES AND LI'S AT -2. EVEN THOUGH SUFFICIENT MOISTURE AND
ADEQUATE INSTABILITY EXISTS ACROSS THE FORECAST AREA 06Z RUC AND 03Z
MESO-ETA SHOW INCREASING SUBSIDENCE ON WESTERN SIDE OF HURRICANE
FLOYD OVER THE ATLANTIC WILL BEGIN TO MOVE INTO THE CWA BY EARLY THIS
AFTERNOON. THIS ALONG WITH FAIRLY WARM MID LEVEL TEMPS ~-4 TO -5 C
SHOULD KEEP PROSPECTS FOR SHOWERS/TSTMS A BIT LOWER TODAY THAN
PREVIOUS DAYS...SO PLAN TO TRIM BACK ON POPS SOME FROM PREVIOUS
PACKAGE IN MORNING UPDATE.
MARINE...CURRENT BUOY DATA INDICATING INCREASING NORTHEASTERLY FLOW
WITH BUOY036 WEST OF BAYPORT NOW INDICATING SUSTAINED WINDS AT 15
KNOTS. ASIDE FROM SOME MINOR WORD TWEAKING PREVIOUS MARINE PACKAGE
LOOKS IN GOOD SHAPE AND NO REAL CHANGES EXPECTED AT THE MOMENT.
THANKS FOR COORD KMLB. COASTAL PACKAGE WILL BE OUT SHORTLY.
MCMICHAEL
FXUS62 KEYW 131311 fl
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1055 AM EDT MON SEP 13 1999
STRONG OCCLUDED SFC LOW CONTINUES TO SIT AND SPIN N OF LAKE
SUPERIOR...WITH THE ASSOCIATED COLD FRONT NOW WELL EAST OF CWA. FOG
HAS LIFTED INTO LOW CLOUDS ACROSS HIGHER TERRAIN IN NRN LOWER MI
LATE THIS MORNING. SUBTLE BOUNDARY HAS MOVED ONSHORE ACROSS NW LOWER
MI...WITH A SLIGHT WIND SHIFT AND DROP IN DWPT BEHIND IT.
MODIFIED 12Z APX SOUNDING FOR 21Z THIS AFTERNOON YIELDS LESS THAN
200 CAPE AND LI'S OF -1...WITH THE MAJORITY OF INSTABILITY REMAINING
IN LOW LEVELS. LATEST RUC CONTINUES TO ADVERTIZE ARRIVAL OF
SIGNIFICANT CAA AND WRAP-AROUND MOISTURE ACROSS CWA WILL HOLD OFF
UNTIL LATE AFTERNOON AND EVENING. HOWEVER...INCREASINGLY UNSTABLE
LOW LEVELS WILL SPELL OUT DIURNAL CU AND SHRA ACROSS ENTIRE CWA FOR
THE AFTERNOON...WITH BETTER CHANCES FOR LAKE CONTRIBUTION TONIGHT
INTO TUESDAY.
WILL FRESHEN WORDING FOR THE AFTERNOON...BUT WILL STICK WITH THE
MAIN THEME OF PARTLY SUNNY WITH SCATTERED SHOWERS FOR ALL LOCATIONS.
WILL HAVE TO INTRODUCE MENTION OF THUNDER IN ERN UPR AND NW AND N
CENTRAL LOWER MI ZONES BASED ON RADAR TRENDS OVER THE PAST HALF
HOUR. INSTABILITY IS NOT OVERLY IMPRESSIVE AND MOISTURE IN THE DRY
SLOT IS NOT PLENTIFUL...BUT BOUNDARY MOVING THROUGH THE REGION
APPEARS TO BE JUST ENOUGH TO FOCUS CONVECTION ALONG IT AND FEED OFF
ANY LIMITED INSTABILITY AVAILABLE.
.APX...NONE.
EME
FXUS63 KMQT 130831 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1042 AM CDT MON SEP 13 1999
A BROAD CYCLONIC FLOW WILL REMAIN THE MAIN WEATHER FEATURE OVER THE
CWA FOR THE NEXT TWO DAYS. LATEST RUC AND 12Z ETA INITIALIZED A VORT
MAX OVER NW MN WHICH IS EVIDENT IN THE WATER VAPOR IMAGERY. THIS
FEATURE TO MOVE SOUTHEAST ACROSS THE CWA THIS AFTERNOON. SOME 700 MB
OMEGA AND THETA-E ADVECTION PROGGED ACROSS PRIMARILY THE EASTERN
CWA. MORNING RAOBS SHOW THE POTENTIAL FOR SOME CAPE (200-400 J/KG).
THIS COUPLED WITH RATHER STEEP LAPSE RATES SHOULD KEEP SOME SHOWERS
DEVELOPING OVER THE NORTHERN AND EASTERN SECTIONS OF THE CWA THIS
AFTERNOON. WILL ADD A CHANCE OF A THUNDERSTORM TO THE NORTH AND EAST
OF KMSP. WILL CUT BACK A LITTLE ON POPS OVER THE WEST AND USE WIDELY
SCATTERED TERMINOLOGY.
.MSP...NONE.
HILTBRAND
FXUS63 KMPX 130741 mn
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
958 AM EDT MON SEP 13 1999
IR PIX SHOW SCU/CU BLOWING IN OFF THE OCEAN ACROSS SRN CSTL AREA OF
NC. PLENTY OF CLOUDS POISED OFFSHORE SO WILL LIKELY SEE A PTSNY DAY
AT BEST AROUND HERE. COULD MOVE INTO GRAND STRAND LATER THIS AFTN SO
WILL LEAN TOWARD BECMG PTSNY THERE. ELSEWHERE... PLENTY OF SUN
PREVAILS THIS MRNG AS HI PRES KEEPS ITS HOLD ON THE AREA. 12Z
SOUNDINGS FROM CHS/MHX SHOW HIGHER RH AROUND H8 SO SCT CU A POSSIBILITY
THIS AFTN. WILL MAINTAIN MOSNY FCST INLAND. AFTN TEMPS LOOK FINE.
CWF: SEAS CURRENTLY RUNNING 7-8 FT OFFSHORE W/ 4-5 FT SWELL. WINDS
15-20 OFFSHORE BUT CLOSER TO 10-15 NEAR SHORE. MAY TWEAK INITIAL
CONDITIONS BASED ON 15Z OMR. 12Z RUC & 03Z MESO-ETA AGREE W/ A
GENERAL 15-20 KT FCST SO WILL CONTINUE THAT PORTION OF IT. WILL
ISSUE FOLLOW-UP MWS TO CONTINUE HEAVY WORDING OF SWELLS.
.ILM...SMALL CRAFT ADVISORY SURF CITY NC TO SOUTH SANTEE RIVER SC.
LGE
FXUS62 KRAH 131349 nc
CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
940 AM EDT MON SEP 13 1999
IT JUST STARTED RAINING AT ERI AND PCPN AMNTS FM NRN OH MUCH LESS
THAN IT WOULD SEEM LOOKING AT JUST REFLECTIVITIES ON THE REGIONAL
MOSAIC. STILL LIKE THE SOUND OF SPRINKLES BETTER THAN SHOWERS FOR
MOST OF FA. WL SEE WHAT I CAN DO ABT FIRST PD...UNLIKE MID SHIFT...
HAVE PLENTY OF REASONS TO DOUBT THE NGM. RUC AND MM5 BOTH MUCH DRIER
THAN NGM AND ETA SOLNS...WITH MESOETA IN BETWEEN. TIMING APPEARS
SIMILAR WRT FNT IN ALL MDLS (SLOW SLOW SLOW). MUST THEREFORE USE
CURR (DRY) TRENDS AND WL CUT BACK ON MOST PRECIP WORDING. TEMPS MAY
NEED TO BE TWEAKED FOR CLD COVER.
WORK ZONES SOON.
.CTP...NONE.
DANGELO
FXUS61 KPHI 130725 pa
CENTRAL PENNSYLVANIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
910 PM EDT SUN SEP 12 1999
INTERESTING VORT MAX WENT BY AT HI LVLS THIS AFTN WITH SOME CB TOPS
DEVELOPING WITH BASES ABOVE 15KFT. NO PRECIP ANYWHERE BUT LOTS OF
SNOW VIRGA COMING OUT OF CB TOPS. RUC SHOWED THIS NICELY. WHAT IS
LEFT OF THIS HI LVL CONVECTION IS UP OVR SW NEW ENG.
24 HR TEMPS 4 TO 8F WARMER THAN YDY AT THIS TIME. ERI IS 14F
WARMER. AFTN TEMPS REACHED THE LOW 90S OVR OH IN SW FLO JUST AHEAD
OF APROACHING CFRNT. MODELS DO NOT BRING THAT AIR E OF MTNS AT THE
SFC OR AT 85H. WITH THE SFC HI TO THE NE OF OUR BEAUTIFUL STATE
THERE COULD BE A CASE MADE FOR A COOL AIR DAM...IF THERE WERE CLDS
TO HOLD TEMPS DOWN. FWC TMPS RAN 3F TOO COOL TDY AT MDT AND WILL
PROB BE ABOUT THE SAME TOM. SUBSTANTIAL CLD WILL NOT REACH LWR SUSQ
TIL MID TO LATE AFTN AND THIS WILL ALLOW FULL INSOLATION. WITH RISK
OF A BIG BUST ON THE WARM SIDE WILL BUMP TEMPS UP JUST A BIT FOR MON.
OTHW NO CHANGES.
EUROPEAN HAS BEEN MOST CONSISTANT WITH EVENT THIS COMING WEEK. OTHER
MODELS ARE BACKING OFF A LANDFALL BUT HAVE BEEN INCONSISTANT. AS
USUAL...WE MUST WAIT AND SEE.
.CTP...NONE.
HEAD
pa
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1012 AM EDT MON SEP 13 1999
ANOTHER DAY OF NEAR STASIS AS WEAK SFC RIDGE KEEPS A DRY AIR-MASS
OVER THE REGION. 09Z RUC DRIES OUT THE FRONTAL BAND SUBSTANTIALLY AS
IT ENTERS THE WRN MTNS DURING THE AFTERNOON. 12Z UPPER AIR SHOWS
STRONG H3 JET STREAK PULLING INTO THE UPPER MID-WEST. AS THE JET
IS PULLING AWAY AND RISES TO THE WEST OF THE SFC FRONT ARE NOT THAT
HIGH...FEEL EVEN THE FAR WRN MTNS WL BE E OF THE CLOUD CANOPY.
CURRENT ZONE TEMPS LOOK PERFECT.
.GSP...NONE.
MCAVOY
FXUS62 KCHS 131359 sc
COASTAL BEND FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
1002 AM CDT MON SEP 13 1999
FRONT IS SLOWLY SEEPING DOWN INTO SOUTH TEXAS THIS MORNING. BECAUSE
OF THIS...IT SEEMS THAT AN UBRUPT INCREASE IN WINDS USUALLY SEEN
HERE WILL NOT OCCUR. VISIBLE SATELLITE PROBABLY SHOWING THE BEST
DEPICTION OF MAIN FRONTAL BOUNDARY...AROUND A KLFK-KAUS-KHDO LINE.
STILL SOME PRESSURE RISES OCCURING...SO FRONT WILL MAKE A LITTLE
MORE PROGRESS BEFORE BECOMING STATIONARY NEAR OR AROUND NORTERN CWFA
LATER THIS AFTERNOON...SIMILAR TO 12Z RUC POSITION. AS A RESULT...
PRECIP/CLOUD AND TEMP FORECAST STILL LOOKS REASONABLE. OTHER THAN
REMOVING SOME WORDING TO THE PREVIOUS FORECAST...WILL GENERALLY
LEAVE IT AS IS. UPDATE WILL BE OUT PROBABLY AOA 11 AM.
MAY LOWER THE WINDS A LITTLE FOR THE BAYS FOR THIS AFTERNOON...SINCE
MAIN BODY OF FRONT WILL BE LATER TODAY.
.CRP...NONE.
86/GW
FXUS64 KHGX 131446 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1110 AM EDT MON SEP 13 1999
QUESTION THIS UPDATE WILL BE PRECIP/CLOUDS.
WATER VAPOR LOOP/12Z RAOBS SHOW BROAD UPPER LOW CENTERED JUST NORTH
OF THE MINNESOTA ARROWHEAD...WITH A MULTITUDE OF EMBEDDED
SHORTWAVES. 14Z MSAS ANALYSIS INDICATES A SURFACE FEATURE VERY NEAR
THE UPPER LOW...WITH A TROUGH TRAILING ALONG THE MN/WI BORDER.
CONVERGENCE ALONG THE SURFACE TROUGH WILL PROVIDE THE FOCUS FOR
SHOWER DEVELOPMENT DURING THE DAY. 12Z RUC/03Z MESOETA KEEP ANY QPF
TO OVER THE WESTERN CWA TODAY. RUC SHOWS BOUNDARY LAYER LIS IN THE -1
TO 1C RANGE...THE THE MOST UNSTABLE LIS OVER THE NORTHERN CWA.
FORECAST SOUNDINGS FOR IWD...MQT...AND ERY SHOW STEEP LOW-LEVEL
LAPSE RATES. EXPECT LIGHT SHOWERS WILL ALSO DEVELOP OVER THE EASTERN
CWA WITH SLIGHT FORCING FROM SURFACE CONVERGENCE.
AN EMBEDDED SHORTWAVE PROVIDED THE SYNOPTIC FORCING FOR TSRA
DEVELOPMENT OVER LAKE SUPERIOR THIS MORNING. KMQT 88D/NLDN DATA SHOW
THE THUNDERSTORMS HAD MOVED INTO CANADA. 03Z MESOETA INDICATED CAPES
OF 600-700 J/KG OVER WESTERN LAKE SUPERIOR OVERNIGHT...AND BROUGHT
THIS BULLSEYE NORTHEAST TOWARD THE CANADIAN SHORE THIS MORNING. THIS
AGREES QUITE WELL WITH THE AREA OF TSRA DEVELOPMENT AND MOVEMENT.
FOR THE REST OF TODAY...MESOETA FORECASTS CAPES <200 J/KG FOR THE
CWA. WILL LEAVE OUT MENTION OF THUNDER WITH SHOWERS TODAY.
VISIBLE SATELLITE LOOP SHOWS THE WESTERN CWA PARTLY TO MOSTLY CLOUDY
WITH MORE CLOUDS ON THE WAY. CLEAR BREAKS ARE ALREADY BEGINNING TO
FILL IN. EASTERN CWA IS PRETTY MUCH CLEAR BUT CU WILL DEVELOP WITH A
LITTLE HEATING AHEAD OF SYNOPTICALLY FORCED CLOUD COVER APPROACHING
FROM THE WEST.
WINDS HAVE ALREADY BECOME QUITE STRONG OVER THE SOUTHERN
CWA...CLOSER TO A SPEED MAX OVER WISCONSIN. WINDS WILL PICK UP
ACROSS THE REST OF THE AREA AS THE JET MOVES NORTHEAST. A FEW TWEAKS
ARE NECESSARY TO THE TEMPS...WITH CHANGES IN CLOUD COVER AND PRECIP
DURATION.
.MQT...NONE.
JHB
FXUS63 KAPX 131457 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1012 AM EDT MON SEP 13 1999
ANOTHER DAY OF NEAR STASIS AS WEAK SFC RIDGE KEEPS A DRY AIR-MASS
OVER THE REGION. 09Z RUC DRIES OUT THE FRONTAL BAND SUBSTANTIALLY AS
IT ENTERS THE WRN MTNS DURING THE AFTERNOON. 12Z UPPER AIR SHOWS
STRONG H3 JET STREAK PULLING INTO THE UPPER MID-WEST. AS THE JET
IS PULLING AWAY AND RISES TO THE WEST OF THE SFC FRONT ARE NOT THAT
HIGH...FEEL EVEN THE FAR WRN MTNS WL BE E OF THE CLOUD CANOPY.
CURRENT ZONE TEMPS LOOK PERFECT.
.GSP...NONE.
MCAVOY
FXUS62 KCHS 131359 sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KNOXVILLE/TRI-CITIES, TN
950 AM EDT MON SEP 13 1999
HAVE BEEN WATCHING WEAK RETURNS ON KMRX 88D MOVING EAST INTO OUR
NE PLATEAU COUNTIES. THUS FAR...IT DOES NOT APPEAR THAT MUCH IF ANY
PCPN IS REACHING THE EXTREMELY DRY SURFACE BELOW. SO MAINLY AN AREA
OF MID DECK CLOUDS ADVANCING SLOWLY EASTWARD TODAY AHEAD OF THE COLD
FRONT. MY 11Z SFC ANALYSIS PLACED A PRE-FRONTAL TROF INTO MIDDLE TN
WITH FRONT THRU MUCH OF INDIANA...BARELY INTO FAR WRN KY AND CLOSE
TO ENTERING NW CORNER OF TN. THIS ALL SLIDES SLOWLY E INTO THE CWA
BY THIS EVENING/OVERNIGHT...BUT WITHOUT MUCH DYNAMICS/LIFT SO WILL
JUST MENTION SPRINKLES FOR ALL ZONES TONIGHT...PER DISCUSSION WITH
PREVIOUS SHIFT AND LONG TERM FORECASTER THIS SHIFT.
OTHERWISE...FOR THE SHORT TERM...WILL CHANGE INCREASING CLOUDS TO
MOSTLY CLOUDY FOR THIS AFTN. PLATEAU COUNTIES HAVE BEEN MOISTENING
UP IN THE LOWER LEVELS...AND PER LOOK AT 09Z RUC...WILL INCREASE
RAIN CHANCES T0 30% THERE FOR THIS AFTN. EASTERN MOST CWA SEEMS TO
STILL BE UNDER THE EFFECTS OF THE SURFACE/850 MB RIDGING...SO WILL
MAINTAIN DRY FORECASTS ELSEWHERE. PARTIAL BNA SOUNDING WAS NOT MUCH
HELP WITH TEMP FORECAST FOR THIS AFTN...BUT WILL NOT LIKELY TWEAK
MAX TEMPS ANY AT THIS POINT. RNK 12Z SOUNDING WAS GENERALLY DRY
...STABLE AND STRONGLY CAPPED.
.MRX...NONE.
TG
FXUS64 KMEG 130819 tn
AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE SAN ANGELO TX
1140 AM CDT MON SEP 13 1999
LOW CLOUDS PREVAIL OVER MOST OF WEST CENTRAL TEXAS EXCEPT FOR
HASKELL AND THROCKMORTON COUNTIES WHERE MOST OF THE STRATUS HAS
ERODED. VISIBLE AND IR SATELLITE LOOPS INDICATED THINNING OF
THE STRATUS OVER THE BIG COUNTRY WHILE SOME MID LEVEL CLOUDS PERSIST
OVER THE CENTRAL COUNTIES. RADAR INDICATED A FEW LIGHT RAIN SHOWERS
OVER NORTHERN SAN SABA COUNTY.
THE MAIN FORECAST CHALLENGE IN THE SHORT TERM IS WHEN THE LOW CLOUDS
WILL BREAK UP. THE 15Z RUC MODEL INDICATED THAT THE LOW LEVEL
HUMIDITIES WILL DECREASE SIGNIFICANTLY BETWEEN 18Z AND 21Z WITH
BOUNDARY LAYER TEMPERATURES FORECAST TO BE IN THE LOWER 80S.
HOWEVER...OUR LOCAL SHORT TERM FORECAST PROGRAM INDICATED THAT
TEMPERATURES WOULD ONLY CLIMB INTO THE MID 70S WITH A 2 PM CLEARING.
CURRENT PLAN IS TO GO WITH DECREASING CLOUDS FOR THE BIG COUNTRY
WITH SAME TEMPERATURES...WHILE ELSEWHERE I WILL KEEP IT CLOUDY
WITH DECREASING CLOUDS LATE AND KNOCK HIGH TEMPERATURES DOWN A
NOTCH. RAIN CHANCES WILL BE REMOVED EXCEPT FOR BROWN AND SAN
SABA COUNTIES WHERE A SLIGHT CHANCE OF LIGHT RAIN WILL BE
MAINTAINED THROUGH EARLY AFTERNOON. LOOKS LIKE THIS FRONTAL PASSAGE
IS FINALLY THE REAL DEAL.
.SJT...NONE.
10
FXUS64 KEPZ 131603 AMD tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
305 PM EDT MON SEP 13 1999
AWIPS VISIBLE SATELLITE LOOP SHOWED RNK CWA LOCATED BETWEEN TWO
AREAS OF CLOUDS. ONE AREA CREATED BY TROF ALONG EAST COAST COMBINED
WITH EASTERLY WINDS AND SLIGHTLY UNSTABLE AIR (AS SEEN IN THE MSAS
SFC LI AND SFC MOISTURE FLUX). SECOND AREA OF CLOUDS ASSOCIATED WITH
COLD FRONT TO OUR WEST ACROSS THE OHIO VALLEY. REGIONAL 88D COMPOSITE
AND SFC OBS INDICATED SHOWERS (NO STRIKES ON THE LDS) ENTERING THE
WESTERN SLOPES. THE MME SE PLACES THE AXIS OF PCP NORTH OF FA IN THE
SHORT TERM. THE 15Z RUC PIVOTS A WEAK VORT AROUND THE BASE OF THE
TROF WITH A LIGHT PCPN PRINTED OUT FOR SE WEST VIRGINIA TONIGHT. FOR
ZONES WILL INCLUDE CLOUDS AND A FEW SPRINKLES IN THE WEST FOR
TONIGHT. LONGWAVE TROF OVER CENTRAL US WILL GRADUALLY SHIFT ENE INTO
THE GREAT LAKES. COLD FRONT WILL GET HUNG UP IN THE MOUNTAINS. QUESTION
OF THIS PACKAGE IS WHAT WILL HAPPEN WITH HURRICANE FLOYD ? AT 2 PM
AST...CENTER OF CAT 4 HURRICANE FLOYD WAS LOCATED NEAR 24.2 N AND
73.0 WEST...ABOUT 470 MILES ESE OF MIAMI FLORIDA. FLOYD IS MOVING
TOWARDS THE WEST NEAR 15 MPH. A GRADUAL TURN TOWARD THE WEST-NW IS
EXPECTED TONIGHT FOLLOWED BY A TURN TOWARDS THE NORTHWEST ON
TUESDAY. MAX SUS WINDS ARE NEAR 155 MPH AND PRES WAS 926 MB. SEE THE
NATIONAL HURRICANE CENTER FOR LATEST ADVISORY AND PATH. SURROUNDING
WFOS...THANKS FOR THE COORDINATION CALLS AND DISCUSSION. ZONE WILL
BE OUT AROUND 335 PM. HAVE A GOOD NIGHT.
.RNK
VA...NONE.
WV...NONE.
NC...NONE.
KK
FXUS61 KAKQ 131425 va