SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
912 AM MST SAT OCT 16 1999
SYNOPSIS...A LOW PRESSURE SYSTEM OVER THE GULF OF CALIFORNIA WILL
MOVE ACROSS NORTHWEST MEXICO THIS AFTERNOON. HOWEVER IT WILL COME
CLOSE ENOUGH TO GENERATE A THUNDERSTORM OR TWO NEAR THE MEXICAN
BORDER. MEANWHILE...A STRONG COLD FRONT OVER SOUTHERN UTAH WILL MOVE
THROUGH SOUTHEAST ARIZONA SUNDAY MORNING. THIS FRONT WILL BRING
COOLER AND MORE SEASONABLE TEMPERATURES TO THE REGION FOR THE FIRST
HALF OF THE UPCOMING WEEK.
DISCUSSION...MODELS UNDERDID THE MOISTURE WHICH HAS MANAGED TO WRAP
INTO THE UPPER LOW CENTERED NEAR ISLA ANGEL DE LA GUARDA AT 15Z.
PRECIP WATER AT TUCSON HAS CLIMBED TO 0.71", AND WITH ABOUT 2C OF
COOLING IN THE 500-300MB LAYER FORECAST BY THE RUC, CAPES WILL TOP
OUT NEAR 500J/KG THIS AFTERNOON. MOST OF THE SYNOPTIC LIFT IS
GRAZING THE MEXICAN BORDER NEAR THE 700MB LIMITING STREAMLINE. THE
MID SHIFT SET ME UP WELL FOR A SWITCH TO ISOLATED WORDING SE OF
TUCSON, BUT WITH DECENT CAPES AND LIGHTNING STRIKES SOUTH OF
NOGALES, WE'LL GO AHEAD AND INTRODUCE SOME THUNDER, TOO. I CAN'T
RULE OUT A SPRINKLE OR TWO IN TUCSON EARLY THIS EVENING GIVEN OUR
INSTABILITY, BUT WITH THE AREA CAUGHT BETWEEN THE UPPER LOW TO THE
SOUTH AND THE COLD FRONT TO OUR NORTH, WE'LL WAIT FOR ACTUAL
DEVELOPMENT BEFORE COMMITTING.
FORECAST FOR SUNDAY IS LOOKING QUITE INTERESTING. FOR THE 2ND RUN
NOW, THE ETA AND NGM ARE CLOSING OFF A 700MB CIRCULATION ALONG THE
COLD FRONT SUNDAY MORNING WHICH THEN LINGERS OVER THE WESTERN CWA
THROUGH MONDAY MORNING. THAT MAKE SENSE GIVEN THE STRONG VORT MAX
DROPPING INTO THE BASE OF THE TROUGH. BOTH THE NGM AND ETA ALSO
CLOSE OFF A 500MB CIRCULATION OVER THE EASTERN RIM. ALL THIS
INDUCES A FAIR AMOUNT OF UPSLOPE, MID LEVEL DIVERGENCE, ISENTROPIC
LIFT, AND LOW LEVEL MOISTURE CONVERGENCE EAST OF TUCSON,
PARTICULARLY IN THE WHITES. THE NEW NGM EVEN KICKS OUT A SWATH OF
0.25" FROM TUCSON EAST. THE MID AND UPPER LEVELS WILL BE AWFULLY DRY
BY THEN, BUT WITH SO MANY PLUSES OUT THERE, WE MAY NEED TO INCREASE
CLOUD COVER AND INSERT SOME SHOWERS. THE PRESENCE OF THE LOW WILL
ALSO MEAN LESS WIND AND WOULD REQUIRE A DOWNWARD ADJUSTMENT ON
HIGHS. 850-700MB THICKNESS LINEAR REGRESSION ONLY YIELDS A HIGH OF
81 IN TUCSON ON THE NEW ETA WITH UPPER 70S ON THE CLOUDIER/WETTER
NGM. PYTLAK.
.TWC...NONE.
FXUS65 KFGZ 161606 az
NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
900 AM MST SAT OCT 16 1999
SYNOPSIS...A DRY COLD FRONT WILL MOVE ACROSS NORTHERN ARIZONA TODAY
BRINGING BREEZY CONDITIONS AND COOLER AIR TO THE NORTHLAND FOR THE
WEEKEND. MOISTURE WILL BE VERY LIMITED WITH THIS WEATHER
DISTURBANCE WITH ONLY A FEW HIGH CLOUDS EXPECTED. SUNNY AND WARMER
WEATHER WILL RETURN TO THE REGION NEXT WEEK AS AN AREA OF HIGH
PRESSURE MOVES INTO THE SOUTHWEST.
DISCUSSION...12Z ETA-NGM INDICATING A NEW WRINKLE TO THE LONGER
TERM FCST...BY BRINGING 5H TROUGH MOVING INTO THE FOUR CORNERS AREA
MORE IN PHASE WITH WEAKENING CUT-OFF LOCATED OVER THE BAJA COAST BY
SUNDAY NIGHT. THIS ALLOWS MORE MOISTURE TO CREEP INTO EASTERN
AZ...ALONG WITH ASSOCIATED DYNAMIC LIFT. FOR NOW...NOT TOO
CONVINCED THAT LOW LEVEL MOISTURE WILL MAKE IT WEST OF THE
DIVIDE...BUT THIS WILL NEED TO BE WATCHED. FRNTL BOUNDARY MAKING
ITS WAY S INTO CENTRAL AZ AT THIS TIME PER WV IMAGERY AND LATEST
RUC PROG. TIGHTENING GRADIENT AND STRONG CAA STILL PROGGED TONIGHT
AND SUNDAY BY LATEST ETA-NGM...AND MAIN FCST PROBLEM WILL BE
FCSTING WINDS TONIGHT. A NOCTURNAL WIND ADVISORY MAY BE NEED SINCE
FCSTED WINDS IN THE 35KT+ RANGE OVER NRN AZ LATER TONIGHT. POSSIBLY
EVEN A HIGH WIND WATCH FOR AREAS EAST OF FLG. ONLY QUESTION
IS...WILL INVERSIONS SET UP AND DISALLOW WINDS FROM MIXING TO THE
SFC OVERNIGHT? SOMETHING TO PONDER FOR THE AFTERNOON PACKAGE.
SUNDAY IS CERTAINLY SETTING UP TO BE A WINDY DAY ACROSS NRN AZ AND
MORNING ADVISORIES WILL LIKELY BE NEEDED. FOR THE SHORT TERM...SOME
CI NOTED FROM SAT IR IMAGERY THIS MORNING...AND MOSTLY SUNNY FCST
HOLDING STRONG. PLANNING NO UPDATES. MCGRATH
.FLG...NONE.
FXUS65 KPSR 160941 az
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
647 PM CDT SAT OCT 16 1999
RADAR AND STLT IMAGERY INDC THAT MID/HIGH LVL CLOUDS ARE EXPANDING
FM NE INTO MUCH OF FA SO WL UP MENTION OF CLOUD COVER. THIS APPRS
TO BE IN RESPONSE TO DIFFERENTIAL PVA AHD OF APCHG LG WV TROF.
ISENT LIFT ARND 600 MB ALSO NOTED IN FBY PROFILER AS IS LATEST RUC
H7/H3 FRONTOGENETICAL FORCING. UVM HIGH BASED ENOUGH THAT PCPN NOT
XPCD FOR TIME BEING WITH DRY AIR IN LOW LVLS. WL HOLD OFF ON ANY
OTHER CHGS TIL 00Z UPR AIR DATA ARRIVES.
.DSM...NONE
SMALL
FXUS63 KDMX 162005 ia
AREA FORECAST DISCUSSION...CORRECTED.
NATIONAL WEATHER SERVICE CARIBOU ME
1031 AM EDT SAT OCT 16 1999
SYNOPSIS:
A WARM FRONT WAS MOVING THROUGH AROOSTOOK COUNTY THIS MORNING. THE
FRONT HAS PRODUCED AN AREA OF SHOWERS AND EVEN A FEW RUMBLES OF
THUNDER. THE FRONT AND MOST OF THE SHOWERS WILL MOVE JUST NORTH OF
FORT KENT THIS AFTERNOON.
HIGH PRESSURE IS HANGING ON IN CENTRAL AND EASTERN SECTIONS. THE HIGH
WILL BRING A GOOD DEAL OF SUNSHINE AND WARMER TEMPERATURES THIS
AFTERNOON. ALTHOUGH AN INCREASING SOUTHWEST WIND WILL MAKE IT FEEL A
BIT COOLER IN OPEN AREAS.
TECHNICAL DISCUSSION:
RUC MODEL LOOKS LIKE IT HAS GOOD HANDLE THRU EVENING WITH WFNT LFTG
NORTH OF AREA THIS AFTN. NXT BATCH OF PRECIP OVR GREAT LAKES SHOULD
THEN MISS US TO THE NORTH.
GOOD WAA H85-H70 ENOUGH FOR SOME IMBEDDED CONVECTION THIS MORNING
OVER NORTHERN ME. LOOKS LIKE CATEGORICAL SHOWERS OVR NORTHERN ZONES
THIS MORNING BECOMING SCT POPS AGAIN BY EVENING.
SOME LLVL SC HAS FORMED FM PENOBSCOT BAT EASTWARD TO NEARLY EASTPORT.
THINK THIS AREA SHOULD BREAK UP A BIT THIS AFTERNOON...THEN REFORM
THIS EVENING.
.CAR...NONE.
COBB
FXUS61 KCAR 161432 AMD me
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
953 AM EDT SAT OCT 16 1999
SYNOPSIS:
A WARM FRONT WAS MOVING THROUGH NORTHERN THIS MORNING. THE FRONT
HAS PRODUCED AN AREA OF SHOWERS AND EVEN A FEW RUMBLES OF THUNDER.
THE FRONT AND MOST OF THE SHOWERS WILL MOVE JUST NORTH OF FORT KENT
THIS AFTERNOON.
HIGH PRESSURE IS HANGING ON IN CENTRAL AND EASTERN SECTIONS. THE HIGH
WILL BRING A GOOD DEAL OF SUNSHINE AND WARMER TEMPERATURES THIS
AFTERNOON. ALTHOUGH AN INCREASING SOUTHWEST WIND WILL MAKE IT FEEL A
BIT COOLER IN OPEN AREAS.
TECHNICAL DISCUSSION:
RUC MODEL LOOKS LIKE IT HAS GOOD HANDLE THRU EVENING WITH WFNT LFTG
NORTH OF AREA THIS AFTN. NXT BATCH OF PRECIP OVR GREAT LAKES SHOULD
THEN MISS US TO THE NORTH.
GOOD WAA H85-H70 ENOUGH FOR SOME IMBEDDED CONVECTION THIS MORNING
OVER NORTHERN ME. LOOKS LIKE CATEGORICAL SHOWERS OVR NORTHERN ZONES
THIS MORNING BECOMING SCT POPS AGAIN BY EVENING.
SOME LLVL SC HAS FORMED FM PENOBSCOT BAT EASTWARD TO NEARLY EASTPORT.
THINK THIS AREA SHOULD BREAK UP A BIT THIS AFTERNOON...THEN REFORM
THIS EVENING.
CCF
BGR UB 061/052/067/045/050 **--3
CAR EE 052/044/057/040/048 **344
.CAR...NONE.
COBB
FXUS71 KGYX 161325 me
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1100 PM EDT SAT OCT 16 1999
...UPDATE TO END PCPN AND ALLOW SKIES TO BECOME PARTLY CLOUDY...
PCPN ALMOST OUT OF JXN COUNTY AT 11PM... WILL COVER THAT IN NOWCAST.
OTHERWISE... RUC SHOWS FCST BY OTHER MODELS IN BRINGING DRY AIR IN
WILL ALLOW CLOUDS TO BRAKE UP. IR LOOPS SHOW CLOUDS THINNING AND
NORTH WINDS TYPICALLY ALLOW LOW CLOUDS TO BRAKE UP ANYWAY AT NIGHT
DUE THE LAND BREEZE CIRCULATION. SO WILL UPDATE ALL ZONES TO FCTS
BECOMING PARTLY CLOUDY (MAY ACTUALLY BECOME MOSTLY CLEAR BUT WILL
NOT WORRY ABOUT THAT).
.GRR...NONE.
WDM
FXUS63 KAPX 170212 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1005 PM EDT SAT OCT 16 1999
00Z SFC CHART SHOWS TROF EXTENDING WNW FM LO PRES N OF LK HURON ACRS
NRN LK SUP INTO SW ONTARIO. THIS SFC TROF ASSOCIATED WITH UPR SHRTWV
OVR SW ONTARIO PER WV LOOP THAT APPEARS ON IMAGERY TO BE MOVG SLOWLY
EWD. WITH SHRTWV STILL TO W...SFC TROF HAS ACTUALLY MOVD SLOWLY NWD
THIS EVNG...AS SHOWN BY CYQT WNDS BACKING FM E (N OF TROF) TO W (S
OF TROF). CWA IN MDTLY STRG...NEUTRAL TO ALMOST ACYC WNWLY FLOW S OF
THIS TROF. CLD MASS THAT WAS OVHD TDAY HAS PRETTY MUCH SHIFTED E OF
CWA WITH BACK EDGE OF LO CLD NOW E OF MUNISING-ISQ. LOTS MORE LO CLD
NOTED OVR NRN MN/WRN LK SUP SPRDG INTO WRN ZNS ASSOCIATED WITH
ABUNDANT MSTR BLO H7 INVRN AS DEPICTED ON 00Z INL SDNG. BUT WITH
QVECTOR CNVGC ASSOCIATED WITH SW ONTARIO SHRTWV REMAINING N...JUST A
COUPLE OF SPRINKLES RPRTD. CNTRL CWA MCLR ATTM AS LO LVL ACYC FLOW
DOWNSLOPING OFF HIER TERRAIN IN ABSENCE OF ANY UPR LVL FORCG. BUT
ERN EDGE OF LO CLD IN WRN ZNS APPEARS TO BE MOVG SLOWLY EWD. 01Z SFC
TEMPS/00Z H85 TEMPS IN WNWLY FLOW S OF SFC TROF VARY FM UPR 30S/-5C
(INL) ACRS NRN MN TO NR 50/+3C (GRB) ACRS ERN ZNS.
MAIN FCST CONCERNS TNGT ARE TRACK OF SW ONTARIO SHRTWV/SFC TROF...
PCPN COVG AND CLD TRENDS/TEMPS. EXAMINATION OF IR/WV LOOPS SUG MOST
RECENT RUCS APPEAR TO HAVE INITIALIZED SHRTWV A BIT TOO FAR E...AND
PROGRESSION OF SYS APPEARS TO BE SLOWER E THAN FCST BY PREVIOUS
RUCS. AS SUCH...SFC TROF HAS HAD A HARDER TIME MOVG S THAN
ORIGINALLY FCST...AND IN FACT HAS MOVD N. BUT SYS SHUD SPEED UP A
BIT AND SHEAR OUT AS IT ENCOUNTERS FASTER WSWLY UPR FLOW PRESENT
FARTHER E PER 00Z RAOBS. XPCT SFC TROF TO PUSH S ONLY AFTR UPR
SHRTWV SHIFTS TO E AND LO LVL FLOW TAKES ON A MORE NLY COMPONENT.
SINCE LATEST RUC INDICATES SFC TROF AND BEST LO LVL CNVGC WL REACH
NR NRN TIP OF KEWEENAW ONLY TOWARD 09Z...XPCT SCT PCPN TO DVLP OVR
KEWEENAW ONLY TOWARD DAWN. ONLY A FEW SPRINKLES PSBL IN UPSLOPE FLOW
OVER WRN ZNS BEFORE THEN. HAVE THUS PUSHED BACK TIMING OF PCPN
ARRIVAL OVR NW ZNS AND REMOVED PCPN MENTION FM BARAGA COUNTY.
ALTHOUGH H85 TEMPS FALL OFF WELL BLO ZERO TO W...21Z RUC PROGS
H100-85 THKNS ONLY TO ABOUT 1310M BY 09Z. GIVEN UNSTABLE LOOK TO LWR
INL PROFILE...HI BNDRY LYR TEMPS ATTM AND PASSAGE OF AIRMASS OVR
RELATIVELY WARM LK SUP...XPCT ONLY LIQUID PCPN.
DOWNSLOPE AREAS E OF MQT-IMT SHUD REMAIN CLR-PCLDY TNGT AS
QVECTOR CNVGC PROGGED TO N DURG NGT. ONLY XCEPTION WL BE ERN ALGER/
LUCE ZNS NR LK SUP IN FVRBL TRAJECTORY OFF LK SUP WITH SC DVLPG WITH
DELTA-T ARND 11C AND SOME QVECTOR CNVGC AHD OF UPR SHRTWV OVRNGT.
COMBINATION OF WND REMAINING HI IN CAD/UNSTABLE LWR PROFILE AND CLD
WL KEEP TEMPS FM FALLING TOO FAR OVRNGT PER UPSTREAM MIN TEMPS SAT
MRNG. MADE A FEW MINOR CHGS TO SECOND PD TO ACCOMODATE CHGS IN FIRST
PD.
.MQT...NONE.
KC
FXUS63 KDTX 170125 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
925 PM EDT SAT OCT 16 1999
QUITE A FEW SHOWERS HAVE DEVELOPED ALONG AND JUST BEHIND THE COLD
FRONT. THIS FRONT WILL BE EXITING SE LOWER AROUND MIDNIGHT. HAVE
UPDATED ZONES TO HANDLE THE NUMEROUS SHOWERS. BOTH ETA AND NGM SHOW
AN AREA 80 PCT OR HIGHER RH IN THE LAYER FROM 850-700 MB MOVING ACROSS
THE EXTREME SE PORTION OF THE CWA OVERNIGHT. HOWEVER LATEST RUC
HINTING AT SOME DRYING TAKING PLACE IN THE SAME LAYER. GIVEN THE
AMOUNT OF SHOWERS DOWNSTREAM...WILL HAVE THE FORECAST LEANING TOWARDS
THE ETA/NGM SOLUTIONS AND NOT MENTION ANY ENDING TIME FOR THE
EXTREME SE PORTION OF THE CWA. SHOWERS ALREADY ENDING IN MIDLAND AND
BAY COUNTIES AND SHOULD BE ENDING IN THE OWOSSO...FLINT... AND BAD
AXE AREAS BY MIDNIGHT.
TEMPERATURE FORECAST LOOKS OK FOR NOW.
.DTX...NONE.
KEYES
FXUS63 KAPX 162008 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
400 PM EDT SAT OCT 16 1999
MAIN FCST CONCERNS INCLUDE TIMING/COVERAGE/TYPE OF PCPN SUNDAY INTO
SUNDAY NIGHT.
MID/UPR LVL PATTERN FEATURES RDG OVER WESTERN STATES...TROFFING FORM
GRT LAKES AND PLAINS INTO THE ROCKIES... AND A RIDGE OVER THE EAST. 1005
SFC LO HAD MOVED NORTH OF GEORGIAN BAY WITH TROF EXTENDING WESTWARD
THROUGH LK SUPERIOR TO CYQT AND LAKE WINNIPEG. LINGERING BAND OF
-RA/-DZ INTO CNTRL LK SUPERIOR AND NRN UPR MI ASSOCIATED WITH DPVA
AND 850-500 QVECT CONV WITH TAIL OF SHRTWV MOVING TOWARD NRN LAKE
SUPERIOR...PER WV LOOP AND 18Z RUC.
MAIN MDL DIFFERENCES THROUGH SUNDAY CONCERN HANDLING OFF SFC TROF
DROPPING TO THE SOUTH THROUGH LK SUPERIOR. HAVE DISCOUNTED NGM WITH
INADEQUATE HANDLING OF GRT LAKES LLVL THERMAL FEATURES. EVEN LOW
RES 80 KM ETA KEEPS TROF AS MUCH BETTER DEFINED FEATURE WITH MORE
CONSISTENT SLOWER PROGRESSION. AVN TIMING SIMILAR TO ETA.
FOR THIS EVENING....850-500 DRYING SHOULD PRECLUDE ANY SIGNIFICANT
PCPN FOR UPR MI AS SUBSIDENCE AND STRONG 850-500 QVECTOR DIV
DOMINATE UPR MI. OVERNIGHT...SFC TROF AND DEEPER MOISTURE BEGIN TO
EDGE TO THE SOUTH TOWARD KEWEENAW WHERE SCT PCPN LATE MENTIONED.
SUNDAY...BEST CHANCE FOR RAIN WILL PROGRESS FROM NORTH TO SOUTH WITH
FOCUS ACRS NORTH CNTRL UPR MI. SIGNIFICANT LAKE ENHANCED PCPN
EXPECTED WITH H85 TEMP OF -3C GIVING DLT/T OF 13C...BAND OF
850-500 QVECTOR CONV WITH MID LVL TROF...GOOD 950 CONVERGENCE...DEEP
MOISTURE AND LACK OF INVERSION. BEST ENHANCEMENT FACTORS EXPECTED
BTWN 15Z-21Z. SHORELINE CONVERGENCE EFFECTS WITH 340-360 WIND WILL
ALSO FAVOR MQT COUNTY. WILL TAPER TO SCT POPS ACRS THE SOUTH. AS FOR
PRECIP TYPE...HAVE DOWNPLAYED SNOW WORDING. WARMER 1000-850
THICKNESSES AS A GUIDE SUGGESTS COLDER AIR WILL NOT FILTER IN UNTIL
LATER SUNDAY AFTERNOON. ANY SNOW WILL BE MAINLY OVER HIGHER TERRAIN
WITH SHALLOWER WARM LAYER.
SUNDAY NIGHT...PCPN WILL WIND DOWN AS THE SFC TROF SAGS FARTHER TO
THE SOUTH. H7 DRYING AND LOWERING INVERSION HGHTS ALONG WITH
INCREASING 950-800 WIND SHEAR SHOULD SPELL END TO LAKE PCPN.
LATE MONDAY THROUGH INTO MONDAY NIGHT AND EARLY TUESDAY..SHRTWV AND
ASSOCIATED SFC LO/TROF FCST TO EMERGE FROM MANITOBA AND NRN PLAINS
TOWARD UPR MI BRINGING CHANCE OF RAIN/SNOW SHOWERS...GIVEN MRF
850-1000 THICKNESS AROUND 1305M...PER 12Z AVN.
IN THE EXTENDED...MOST LONG TERM MDLS IN AGREEMENT IN OVERALL
PATTERN WITH CONTINUATION OF BROAD TROF ACRS CENTER OF CONUS INTO THE
GRT LAKES BTWN RIDGES OVER THE ERN PACIFIC AND WRN ATLANTIC.
MRF AS IN PREVIOUS RUNS...MOST AMPLIFIED BRINGING IN MORE
SUBSTANTIAL INTRUSIONS OF COLD AIR LATER IN THE WEEK. UKMET WAS
RELATIVELY CLOSE TO MRF WITH ECMWF...CANADIAN AND ESPECIALLY NOGAPS
EACH SLIGHTLY FLATTER WITH PATTERNS BY WED/THURS. ENSEMBLES FROM
00Z/15 ALSO REASONABLY CONSISTENT WITH 00Z/16 OPERATIONAL MRF. WILL
GENERALLY LEAN TOWARD MRF BUT WILL NOT GET CARRIED AWAY YET WITH
COLD AIR LATE IN THE WEEK. H85 TEMPS FCST TO -10C FRIDAY AND -12C TO
-14C BY 00Z/SUN WITH NW FLOW SEEM A BIT OVERDONE.
NEVERTHELESS...EXPECT LES POTENTIAL WITH DLT/T TO NEAR 20C. POPS AOA
CLIMATOLOGY WARRANTED THROUGH THE PERIOD WITH SHRTWVS ARRIVING
APPROXIMATELY EVERY 24 HRS. TIMING...AS USUAL... DIFFICULT IN SUCH A
REGIME AS SUCCESSIVE MRF RUNS SHOW SIGNIFICANT DIFFERENCES IN TIMING
AND INTENSITY OF SHRTWVS WED AND THURS.
.MQT...NONE.
JLB
FXUS63 KGRR 161934 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
1130 AM EDT SAT OCT 16 1999
HAVE UPDATED FOR CHC POPS ALL ZONES AND TO LOWER MAX TEMPS A BIT.
WHILE A FAIR AMOUNT OF MOISTURE EXISTS ALONG/AHEAD OF THE COLD FRONT
WITH 850 DEWPTS NR 9C... UPPER SUPPORT IS LACKING SOMEWHAT. VORT THAT
BROUGHT BULK OF PCPN EARLIER THIS MORNING CONTINUES AWAY TO THE NE.
A TAIL DOES EXTEND BACK TO THE SW ON WATER VAPOR AND IR IMAGERY TO
ANOTHER WEAKER VORT IN ILLINOIS... AND COINCIDES WITH CURRENT SHOWER
ACTIVITY. HOWEVER THIS FEATURE IS PROGGED TO LOSE DEFINITION AND
FURTHER WEAKEN THIS AFTERNOON. FRONT IS STILL MAKING EWD PROGRESS
THOUGH AND COULD STILL GENERATE A FEW SHOWERS. A TSTM STILL PSBL
WITH LATEST RUC SHOWING LI/S DROPPING BELOW THIS AFTERNOON.
LOWERED MAX TEMPS BASED ON LATEST READINGS...LAMP DATA...AND CLOUD
COVER. HOWEVER LAST FEW VSBL SATL PICS SHOW SEVERAL BREAKS
DEVELOPING.
.GRR...NONE.
MEADE
FXUS63 KAPX 161513 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1113 AM EDT SAT OCT 16 1999
LATEST SURFACE ANALYSIS HAS SURFACE LOW LOCATED OVER THE STRAITS OF
MACKINAC...MOVING FAIRLY QUICKLY TO THE NORTHEAST. TRAILING COLD
FRONT EXTENDS THROUGH LAKE MICHIGAN INTO NORTHEAST ILLINOIS.
SATELLITE IMAGERY SHOWS EXTENSIVE CLOUD COVER ACROSS UPPER GREAT
LAKES...WITH BEST ENHANCEMENT HAVING MOVED NORTHEAST INTO CANADA.
MAIN CONCERN THIS AFTERNOON CENTERS ON RAIN CHANCES.
12Z RUC CONTINUES TO SHOW FROPA OCCURRING ACROSS FORECAST AREA IN
THE LATE AFTERNOON AND EARLY EVENING HOURS. HOWEVER...BEST SUPPORT
FOR WIDESPREAD PRECIPITATION HAS EXITED THE REGION. THE BEST JET
SUPPORT HAS MOVED NORTHEAST INTO ONTARIO AND BEST ISENTROPIC
LIFT/LOW LEVEL INFLOW HAS MOVED EAST. IN FACT...UPPER CONVERGENCE
AND ISENTROPIC DESCENT IS PROGGED ACROSS AREA DURING THE AFTERNOON.
HAVE GENERALLY WORDED PRECIPITATION AS BECOMING MORE SCATTERED IN
ZONES AS A RESULT. HAVE LEFT A MENTION OF THUNDER IN THE FAR
SOUTHEAST AS THIS AREA HAS THE LATEST FROPA AND MOST UPPER SUPPORT
/ALBEIT WEAK/. HAVE MADE POP ADJUSTMENTS TO THE SECOND PERIOD IN
SEVERAL ZONES TO COVER CURRENT AND EXPECTED DIMINISHING TREND.
EXTENSIVE CLOUD COVER AND PRECIPITATION IS KEEPING TEMPERATURES
DOWN. HAVE LOWERED SEVERAL ZONES A CATEGORY AS A RESULT.
.APX...NONE.
BAK
FXUS63 KMQT 161509 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1110 AM EDT SAT OCT 16 1999
13Z SFC ANALYSIS SHOWS COMPLEX 1006MB LOW CENTERED NEAR EASTERN
UP...WITH COLD FRONT EXTENDING S/SW THROUGH SOUTHERN WI AND WESTERN
IL. ONE TROF EXTENDS FROM THE LOW TO THE NE...WHILE ANOTHER SFC TROF
EXTENDS NW INTO SW ONTARIO. THIS SECOND TROF IS ASSOCIATED WITH A
500MB TROF THAT WILL MOVE ACROSS THE CWA SUNDAY. KMQT 88D SHOWS
LARGE AREA OF SHRA DEPARTING EASTERN CWA. SHRA MORE SCATTERED ACROSS
THE REMAINDER OF THE UP...WITH THE BACK EDGE OF PRECIP EVIDENT OVER
THE FAR WESTERN COUNTIES. IR IMAGERY ALSO SHOWS COLDEST TOPS WITH
BAROCLINIC LEAF PUSHING EASTWARD AWAY FROM CWA.
VIS IMAGERY SHOWS MOST OF REGION WITH CLOUD COVER. ONLY CLEAR AREAS
ARE FOUND IN CENTRAL AND SOUTHERN MN. RUC FORECASTS SOME GRADUAL
DRYING IN THE 1000-500MB LAYER RH AND WEAK 700-300MB Q-VEC DIVERGENCE
OVER THE UP THIS AFTERNOON. THIS WILL NOT BE ENOUGH TO ERODE LOW
CLOUD DECK AS SFC TROF BEGINS TO APPROACH CWA AND CAA PATTERN SETS
UP...ENHANCING LAKE CLOUDS. WITH MAIN CORE OF SHOWERS EXITING THE
FA AND SURROUNDING METARS REPORTING LIGHT RAIN/DRIZZLE...WILL JUST
PUT WORD OF PATCHY DRIZZLE IN ALL ZONES. TEMPS LOOK GOOD. DO NOT
EXPECT MUCH CHANGE IN TEMPS GIVEN EXTENSIVE CLOUDS AND EXPECTED
INCREASE OF CAA.
.MQT...NONE.
JS
FXUS63 KDTX 161508 mi
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE GAYLORD MI
330 AM EDT SAT OCT 16 1999
RATHER LARGE AREA OF CONVECTION CONTINUES TO FIRE ALONG THE INVERTED
TROFF ACROSS SRN WI AND NRN IL. PRONOUNCE THETA E RIDGE IS PUNCHING
INTO THIS REGION...AS SFC DWPTS POOL ALONG THE BOUNDARY. 40 KT 850
MB JET AND 50 KT 500 MB JET ARE HELPING TO ORGANIZE AND QUICKLY
DRIVE THE CONVECTION NE TOWARD ERN UPR AND LOWER MI. DEVELOPING VORT
MAX NEAR DVN IS PROVIDING SOME UPPER LEVEL SUPPORT...WITH CONVECTION
DEVELOPING IN THE AREA OF GREATEST DPVA. EVOLUTION OF THIS SYSTEM
AND RESULTING PRECIP WILL BE THE MAIN FOCUS OF THE FORECAST.
LATEST RUC HAS A VERY GOOD HANDLE ON THE SITUATION...AS DOES THE
ETA. NGM IS STILL TOO FAR N AND TOO QUICK WITH THE SFC LOW. ETA
SUGGESTS SFC LOW WILL REACH THE STRAITS AREA BY 18Z...WHICH SEEMS TO
BE REASONABLE GIVEN CURRENT TRACK AND SPEED. DEEPEST MOISTURE IS
ONCE AGAIN ACROSS ERN UPR AND FAR NRN LOWER...BUT EVEN SE SECTIONS
OF THE CWA MOISTEN THROUGHOUT THE COLUMN BY THIS AFTERNOON. WILL
STICK WITH CATEGORICAL POPS FOR ERN UPR MI WHERE DEEPEST MOISTURE
RESIDES. REST OF THE CWA WILL WORD AS LIKELY POPS TODAY...MAINLY
THIS AFTERNOON FOR SE SECTIONS.
00Z KAPX AND UPSTREAM KGRB SOUNDINGS...LIFTING FROM 800 MB... YIELD
CAPES OF LESS THAN 200 J/KG...LI'S AROUND ZERO AND TT'S IN THE MID
TO UPPER 40S. THIN AREA OF CAPE ALONG WITH LOW LEVEL JET...THETA E
RIDGE...VORT MAX AND SUFFICIENT 850-700 MB FRONTOGENETIC LIFT WILL
CONTINUE TO SUPPORT THE POTENTIAL FOR THUNDER TODAY. WAA HAS BEEN
STRONGER THAN EXPECTED EARLY THIS AM...WITH MBL ALREADY IN THE LOW
60S. THUS...WILL HAVE TO BOOST HIGH TEMPS UP A FEW DEGREES.
FOR TONIGHT...ELONGATED AREA OF POST-FRONTAL DPVA SLOWLY MOVES SE
THROUGH THE CWA. BRIEF SHOT OF MID LEVEL DRYING TAKES PLACE LATER
TONIGHT FROM NW TO SE...SO THINK PRECIP SHOULD BE MAINLY AN EVENING
EVENT...EXCEPT IN SE SECTION WHERE DRYING WILL HOLD OFF UNTIL WELL
AFTER MIDNIGHT. WILL ALSO KEEP MENTION OF THUNDER FOR SE ZONES IN
THE EVENING PRIOR TO FROPA.
BIG COOL DOWN AND LAKE EFFECT PRECIP IN THE WORKS FOR SUNDAY.
SIGNIFICANT CAA BEGINS AFTER 06Z SUN AND CONTINUE THROUGHOUT THE
DAY. 850 TEMPS DROP TO -2 ACROSS NRN LAKE MI BY 12Z SUN...AND TO -6
BY 00Z MON ACROSS LAKE SUPERIOR. SUFFICIENT LAKE INSTABILITY...LOW
LEVEL CYCLONIC FLOW...SFC THRU 700 MB RH INCREASING TO 70 TO 80 PCT
AND VIRTUALLY NO INVERSION WILL LEAD TO A GOOD CHANCE FOR LAKE
EFFECT RAIN AND POSSIBLY SNOW SHOWERS...WITH BEST CHANCES FOR SNOW
IN ERN UPR MI AND IN THE HIGHER TERRAIN AREAS OF NRN LOWER MI.
.APX...NONE.
EME
FXUS63 KMQT 160840 mi
EASTERN OKLAHOMA/NORTHWEST ARKANSAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TULSA OK
1120 AM CDT SAT OCT 16 1999
16Z MESONET DATA SHOWS COLD FRONT STRECHING FROM NEAR VINITA TO TULSA
TO W OF ARDMORE WITH BOUNDARY TAKING ON TYPICAL ANTICYLONIC BEND AS
IT ENCOUNTERS THE HIGHER TERRAIN OF FAR ERN OK. THIS HAS SLOWED THE
ERN PROGRESSION OF THE BOUNDARY...BUT STILL EXPECT COLD FRONT TO PUSH
INTO NW AR BY MID AFTERNOON AND FAR SE OK BY LATE AFTERNOON. 12Z RUC
HAS A DECENT HANDLE ON THE THICKER CLOUD COVER TO OUR N...AND SHOULD
SEE SKIES BECOME MOSTLY CLOUDY ACROSS THE ENTIRE FORECAST AREA DURING
THE AFTERNOON. WITH INCREASING CLOUD COVER AND LOW-LEVEL CAA...WOULD
EXPECT TEMPS TO STEADY OUT OR SLOWLY FALL...MAINLY OVER NE OK. HAVE
ALSO SEEN A FEW SHRA/TSRA ACROSS FAR SE OK...AND MAY SEE SOME
INCREASE IN COVERAGE OVER SE OK/NW AR AS FRONT NEARS.
NEED TO RE-ARRANGE ZONE GROUPINGS AND ADJUST TEMPS TO BETTER FIT
POSITION OF COLD FRONT. UPDATED ZONES OUT BY 1630Z.
FCSTID = 18
.TUL...
AR...NONE.
OK...NONE.
FXUS64 KOUN 161544 ok
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
1040 AM CDT SAT OCT 16 1999
LATEST MESONET DATA SHOWS COLD FRONT EXTENDING FROM ARCHER COUNTY TO
WAURIKA TO BOWLEGS TO NEAR TULSA WITH 8H FRONT 150 MILES BEHIND.
PROBLEMS THIS MORNING WILL BE AMOUNT OF CLOUDS THAT DEVELOP AND
AFFECT THIS WILL HAVE ON AFTERNOON HIGHS. CLOUDS HAVE ERODED
SOMEWHAT ACROSS PARTS OF SOUTHWEST KANSAS BUT WITH 8H FLOW NORTHEAST
AND DEWPOINT SPREADS RATHER LOW...CLOUDS SHOULD FILL IN ACROSS
NORTHERN COUNTIES DURING THE AFTERNOON. TEMPERATURES IN THE NORTH
HAVE ALREADY REACH THE FORECAST HIGH SO WILL UP TEMPERATURES THERE.
SOME CLOUDS HAVE FORMED OVER THE REST OF THE FORECAST AREA AND THIS
SHOULD HELP KEEP TEMPERATURES FROM RISING TO MUCH. AS SURFACE FRONT
APPROACHES SE ZONES THIS AFTERNOON...CLOSE TO MAX HEATING...STILL
COULD SEE SOME SHOWERS AND THUNDERSTORMS WITH RUC AND ETA SHOWING AREA
SURFACE MOISTURE CONVERGENCE THERE. WILL REMOVE POPS FROM AFTERNOON
FORECAST WHERE FRONT HAS ALREADY PUSHED THROUGH AS DO NOT EXPECT
POST-FRONTAL CONVECTION. UPDATES TO FOLLOW SHORTLY.
.OUN...
OK...CAUTION ON AREA LAKES ALL ZONES EXCEPT FAR SE.
TX...CAUTION ON AREA LAKES TODAY.
6
FXUS64 KOUN 161130 RTD ok
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
654 AM EDT SAT OCT 16 1999
RUC SHOWS ISENTROPIC LIFT CONTINUING INTO MORNING WITH PERSISTENT
LOW LEVEL MOISTURE. MODELS MOVE IRENE UP E COAST CLOSER TO
NHC MODELS THAN PREVIOUS RUNS. NORTHEAST LOW LEVEL FLOW PERSISTS
INTO SUN MORNING WHILE COLD FRONT MOVES TO MOUNTAINS. MODELS BACK
LOW LEVEL WINDS TO DOWNSLOPE COMPONENT LATE SUN BEHIND IRENE.
ETA/NGM TIME SECTIONS SHOW MOISTURE INCREASE IN LOW LEVELS THROUGH
TODAY...AND MORE RAPIDLY AT MID LEVELS OVERNIGHT. DEEPEST MOISTURE
AND BEST LIFT 12-18Z SUN. ISENTROPIC LIFT WILL CONTINUE TIL SUN
WHEN TROPICAL SYSTEM STEERS FLOW ALONG CONTOURS. WOULD NOT BE
SURPRISED TO SEE SOME SUN ON SUNDAY WITH DOWNSLOPE AND IRENE SO FAR
E. AT THIS TIME...GIVEN PREVIOUS NHC TRACK AND CURRENT RUN OF NHC
MODELS...FAVOR POPS MUCH LOWER THAN MODEL GUIDANCE AND MAINLY IN E
ALONG I-77. MODEL DEW POINTS RISE THROUGH MOST OF PACKAGE. WITH
TRACK FARTHER E THAN MODELS...LOWER DEW POINTS MAY REMAIN OR BE
ADVECTED IN ALLOWING COOLER MINIMUM TEMPERATURES. LIKEWISE...
NE WIND AND INCREASING CLOUDS TO KEEP MAXIMUMS COOL TODAY.
POTENTIAL FOR DOWNSLOPING AND BREAKS IN CLOUDS SUN MAY ALLOW
MAXIMUMS TO RISE...BUT FEEL NGM OVERDONE. BREEZY SUN AS IRENE
TRACKS UP COAST. FINAL DECISIONS TO BE MADE AFTER NHC COORDINATION
CALL.
UPDATE: SATELLITE IMAGERY SHOWS CLOUDS ERRODING IN NC PIEDMONT
AND SC UPSTATE. WILL REWORD CLOUD COVER FOR TODAY.
AVL 67/53/66 123
CLT 70/57/70 345
GSP 70/58/73 234
.GSP...NONE.
JAT
FXUS62 KCHS 160918 AMD sc
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIDLAND TX
320 AM CDT SAT OCT 16 1999
STRONG COLD FRONT DROPPING THROUGH PANHANDLE THIS MORNING BRINGING
COLDEST WEATHER SO FAR THIS FALL. SURFACE ANALYSIS AND KMAF 88D
RADAR INDICATES FRONT LOCATED NEAR A KCDS... KLBB... TO CROSSROADS NM
LINE WITH +3 PRESSURE RISES BEHIND IT AND GOOD PUSH ON H85 FRONT.
FROPA WILL BE EARLIER THAN MODELS OR ZONES INDICATE. EXPECT FRONT IN
PERMIAN BASIN THIS MORNING AND PUSHING THROUGH REST OF AREA TODAY.
SATTELITE/LDS INDICATES THUNDERSTORMS CURRENTLY CONFINED TO EASTERN
US... APPEARS WILL BE DRY PASSAGE FOR MOST OF CWA. SUPPORT FROM
STRONG UPPER LEVEL TROUGH WILL NOT ARRIVE UNTIL LATE SUNDAY AND WILL
BE TOO LATE TO SUPPORT ORGANIZED PRECIPITATION. RUC INDICATING LACK
OF INSTABILITY WHILE ETA SHOWS SOME IN SOUTHEAST THIS AFTERNOON.
COLD AIRMASS AND ISENTROPIC UPGLIDE WILL BE ENOUGH TO BRING CHANCE
FOR SOME PRECIP. WILL LEAVE MENTION OF SHOWERS AND RAIN IN MOST OF
ZONES... BUT MENTION THUNDERSTORMS FOR THE THIS AFTERNOON FOR THE
SOUTHEAST. TEMPS A BLEND OF PREVIOUS FORECAST AND NEW GUIDANCE.
INITIAL NUMBERS FOLLOW.
MAF 79/46/54/39 0320
LSA 75/42/51/35 0320
E41 80/46/56/40 0320
6R6 85/55/62/42 2220
MRF 80/44/55/34 0020
CNM 79/47/56/38 0220
.MAF...
TX...NONE.
NM...NONE.
72
FXUS64 KAMA 160821 tx
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GOODLAND KS
220 AM MDT(320 AM CDT) SUN OCT 17 1999
...FORECAST CONCERN IS TEMPS THIS FORECAST PACKAGE...
06Z SURFACE ANALYSIS SHOWS STRONG HIGH PRESSURE SYSTEM CENTERED OVER
SOUTHERN WYOMING BUILDING SOUTHEAST OVER CWA THIS MORNING. COLD
FRONT EXTENDS THROUGH GULF COAST STATES INTO SOUTH CENTRAL TEXAS.
LIMITED MODEL DATA TO EXAMINE THIS MORNING WITH AVN AND ETA NOT YET
INTO AWIPS. LOOKED AT NGM ECMWF RUC AND NOGAPS. COMPARED TO
YESTERDAY'S MODEL RUNS NGM SEEMS TO BE DOING A GOOD JOB WITH
POSITION AND MOVEMENT OF COLD FRONT TO OUR SOUTH AND HIGH PRESSURE
RIDGE TO OUR NORTHWEST. TODAY STRONG SUBSIDENCE AND A DRIER
ATMOSPHERE FROM THE BUILDING HIGH PRESSURE RIDGE WILL RESULT IN
SUNNY SKIES. NORTH WINDS WILL MAINTAIN SOME CAA WITH MAX TEMPS TODAY
REBOUNDING SOME 5 TO 10 DEGREES UNDER SUNNY SKIES INTO THE 50S
ENTIRE CWA.
FOR TONIGHT HIGH PRESSURE RIDGE SHOULD BE CENTERED OVER WESTERN
KANSAS. SUBSIDENCE CONTINUES AND WINDS SHOULD BECOME LIGHT. GOOD
RADIATIONAL COOLING SHOULD ALLOW OVERNIGHT TEMPS TO FALL INTO THE
UPPER 20S TO AROUND 30 MOST AREAS.
MONDAY SHOULD SEE A WARM UP AS HIGH PRESSURE RIDGE MOVES TO OUR
EAST. SOUTHWEST WINDS IN THE 5 TO 15 MPH RANGE SHOULD HELP WARM THE
ATMOSPHERE WITH TEMPS REBOUNDING INTO THE 60 TO 65 TEMP RANGE.
MOISTURE REMAINS NIL SO SUNNY SKIES SHOULD PREVAIL.
IN THE EXTENDED...MODELS ADVERTISE ANOTHER COLD FRONT TO MOVE
THROUGH CWA ON TUESDAY WITH ANOTHER SHOT OF SOMEWHAT COLDER AIR TO FOLLOW.
WITH MOISTURE SHUT OFF FROM THE GULF OF MEXICO FRONT WILL MOVE
THROUGH AS A DRY FRONT WITH PERHAPS A SCATTERING OF CLOUDS AND WIND
SHIFT. DRY WEATHER SHOULD CONTINUE THROUGHOUT THE EXTENDED PERIOD
THROUGH THURSDAY WITH TEMPS WARMING WEDNESDAY INTO THURSDAY AS UPPER
HIGH PRESSURE RIDGE MOVES INTO CENTRAL PART OF THE U.S.
AVN FAN TEMPS SEEMED TOO LOW SO WENT CLOSER TO FWC MOS TEMPS THROUGHOUT
THIS FORECAST PACKAGE.
.GLD...NONE.
LAMMERS
FXUS63 KICT 170748 ks
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1145 PM CDT SAT OCT 16 1999
CLEAR SKIES OVER MUCH OF FORECAST AREA. LATEST RUC MODEL INDICATES
LOW LEVEL RELATIVE HUMIDITY SUFFICIENT FOR CLOUDS IN NORTHERN AND
WISCONSIN PORTION. LOW TEMPERATURES HAVE BEEN UPDATED FOR COOLER
READINGS WITH DRY AIR AND LESS WIND.
.MSP...NONE.
SCOTT
FXUS63 KDLH 170250 mn
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
238 AM EDT SUN OCT 17 1999
RUC SHOWS ISENTROPIC LIFT DECREASING BETWEEN 09Z AND 12Z. NGM
TIME SECTION PLACES DEEPEST MOISTURE OVER AREA TODAY WITH RAPID
DRYING THIS EVENING AS COLD FRONT ARRIVES AND FLOW BACKS FROM NE
TO N. LITTLE OR NO OMEGA THIS PACKAGE. WITH TROPICAL SYSTEM SO FAR
E WILL NOT INCLUDE POPS FIRST PERIOD E OF MOUTNAINS. SMALL POP IN
MOUNTAINS TODAY WITH FRONTAL CONVERGENCE ZONE ARRIVING...BUT UPPER
SYSTEM TO WEAKEN AS IT IS SHEARED NE. ETA BUFKIT DRIES LEE OF
MOUNTAINS WITH DOWNSLOPE TON/MON. NGM HAS SAME WIND BUT MAINTAINS
CLOUDS. EVEN WITH UPSLOPE FLOW IN MOUNTAINS AFTER FROPA...MOISTURE
LIMITED TO LOW LEVELS AND FLOW NOT EXACTLY ORTHOGANAL TO RIDGE
LINES. WILL CONTINUE SMALL POPS MOUNTAINS FOR UPSLOPE TONIGHT...
BUT WITH MOISTURE EVEN MORE LIMITED MON WILL DROP POP BUT KEEP
CLOUDS. TEMPERATURES TO BE HELD IN CHECK TODAY BY CLOUDS AND NE
FLOW. WITH EARLY EVENING FROPA...COLD ADVECTION WILL HAVE CHANCE
TO AFFECT AREA TONIGHT...MODERATED BY WIND. DOWNSLOPE COMPONENT
MON TO KEEP MAXIMUMS UP IN LEE OF MOUNTAINS...WHILE MOUNTAIN
MAXIMUMS FALL. AGAIN...WINDS TO KEEP TEMPERATURE FALL MON LIMITED.
BELIEVE LOW LEVEL FLOW BEHIND FRONT AS ADVERTISED IN FWC SUPPORTS
LESS CLOUDS LEE OF MOUNTAINS TON AND ESPECIALLY MON. TIGHT GRADIENT
SUPPORTS BREEZY CONDITIONS TIL MID MON...THEN GRADIENT SLACKENS.
FINAL NUMBERS OUT AFTER NHC COORDINATION.
AVL 72/48/65 332
CLT 72/54/70 200
GSP 73/55/71 100
.GSP...NONE.
JAT
FXUS62 KCHS 170315 AMD sc
AREA FORECAST DISCUSSION...CORRECTED TIMING 3RD PARAGRAPH
NATIONAL WEATHER SERVICE RIVERTON WY
300 AM MDT SUN OCT 17 1999
CRNT WX...SFC HIGH OVER NRN COLORADO DOMINATING OUR CWA WITH CLEAR
SKIES AND MOSTLY CALM OR LIGHT WIND...TEMPS IN THE TEENS AND 20S AT
1 AM. IR AND WV SHOW SE SURGE OF MID/UPPR MOISTURE ACROSS NRN
MONTANA ASSOCIATED WITH WEAK SHORTWAVE IN NW FLOW ALOFT. LAST
EVENINGS VISUAL SAT SHOWS NON MOUNTAINOUS SNOW COVER CONFINED TO A
50 TO 6O MILE WIDE E/W SWATH ACROSS THE SOUTHERN 1/2 TO 2/3 OF
NATRONA AND FREMONT CTYS. THIS WILL BE FACTORED INTO TDY'S TEMP
FCST.
THE ONLY CURRENT MODELS TO MAKE IT SO FAR INTO AWIPS SO FAR ARE THE
NGM AND RUC. DETECT NO MAJOR DEVIATIONS BETWEEN THESE AND PREVIOUS
ETA AND AVN. ALL APPEAR TO HAVE INITIALIZED WELL.
SFC TROF WILL BECOME ESTABLISHED OVER ERN WY TDY. LUK FOR BREEZY
CONDITIONS TO DEVELOP SOME AREAS...ESP RKS TO CPR CORRIDOR. WITHOUT
SNOW COVER CONSIDERATION...MODEL THICKNESS HINT THAT TDY'S MAX TEMPS
WILL BE SOME 8 TO 15 DEGREES WARMER THAN YSTDY'S HIGHS...WEST TO
EAST. WILL FACTOR IN SNOW COVER WHERE APPLICABLE. LOOK FOR
INCREASING CLOUDS FROM THE NORTH LATE TODAY AND TONIGHT WITH
APPROACH OF NEXT UPR SYSTEM AND CANADIAN CD FNT.
ON MONDAY...NEXT COLD SURGE PUSHES SSW THEN HANGS UP ALONG
CONTINENTAL DVD. MODELS BRING LT PCPN E OF DVD AS CAA AND WK SHLW
UPSLOPE DEVELOP. WILL FCST SCT SHSN THIS AREA...WITH PTLY SUNNY AND
ISOLD SHWRS WEST.
XTND...MUCH OF THE REMAINER OF THE WEEK LOOKS DRY WITH WARMUP AS NWLY
STRM TRACK SHIFTS EAST AND UPPER RIDGE ENCROACHES FROM THE WEST.
MAY BUMP TEMPS UP A BIT FROM LAST PACKAGE BASED ON NEWEST FAN.
RIW...NONE.
DZ
FXUS65 KRIW 170859 wy
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1105 AM EDT SUN OCT 17 1999
CURRENT APX 88D AND SURFACE OBSERVATIONS SHOWING VERY LITTLE IN THE WAY
OF PRECIPITATION AFFECTING EAST UPPER AND NORTHERN LOWER MICHIGAN THIS
MORNING. CURRENT STLT SHOWING PARTLY SUNNY TO MOSTLY CLOUDY CONDITIONS
CURRENTLY OVER NORTHERN MICHIGAN.
THE LATEST RUC SHOWING A SURFACE TROUGH CURRENTLY OVER LAKE SUPERIOR...
PROGGED TO MOVE SOUTHWARD INTO THE STRAITS REGION THIS AFTERNOON... WITH
A 500 MB UPPER LEVEL TROUGH MOVING INTO NORTHERN LAKE MICHIGAN BY EARLY
EVENING. 850/500 MB DPVA SHOWING THE BEST LIFT ASSOCIATED WITH THE
UPPER TROUGH... TO AFFECT SOUTHERN LOWER MI IN ADVANCE OF THE VORT MAX
SLIDING OVER THE SOUTHERN PART OF THE STATE. THE MAIN FACTOR LIMITING
PRECIPITATION CHANCES OVER THE FORECAST AREA TODAY... WILL BE THE
MOISTURE.
LOWER LEVELS BETWEEN 850/700 WILL REMAIN LESS THAN 40 PERCENT OVER
NORTHERN LOWER THIS AFTERNOON TO AROUND 70-80 PERCENT OVER EAST UPPER
AND STRAITS AREA. WILL KEEP MENTION OF SHOWERS OVER EAST UPPER AND
EXTREME NORTHERN LOWER THIS AFTERNOON DUE TO ITS BETTER LOCATION WITH
LOW LEVEL MOISTURE AND CLOSER PROXIMITY TO THE SURFACE TROUGH. WILL GO
WITH PARTLY SUNNY ACROSS THE REST OF NORTHERN LOWER.
.APX...NONE.
SWR
FXUS63 KGRR 171442 mi
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
320 AM EDT SUN OCT 17 1999
INITIAL COLD FRONT HAS MOVED SE OF LOWER MI EARLY THIS MORNING...
WITH A SECONDARY COLD FRONT ROTATING S AROUND THE SFC LOW INTO NRN
LAKE SUPERIOR AND NRN MN. SCT RAIN AND SNOW SHOWERS HAVE DEVELOPED N
OF LAKE SUPERIOR ALONG AND JUST BEHIND THIS BOUNDARY...AIDED BY THE
LFQ OF AN 85 KT 500 MB JET MAX OVER ERN UPR MI AND ONTARIO. PRECIP
CHANCES FROM AND CAA BEHIND THE SECONDARY FRONT WILL BE THE MAIN
FOCUS OF THE FORECAST TODAY AND EARLY TONIGHT. NE FLOW OFF LAKE
HURON AND SFC RIDGE AXIS BUILDING IN FROM THE W WILL BE THE MAIN
WEATHER FEATURES TO CONTEND WITH LATER TONIGHT AND ON MONDAY.
BASED ON LATEST IR SATELLITE TRENDS AND CURRENT OBS...MODELS SEEM TO
BE HAVING A DIFFICULT TIME RESOLVING THE PROPER LOCATION FOR THE
VORT MAX AND AREA OF GREATEST DPVA RESULTING FROM THE LFQ OF THE JET
MAX. AREA OF DPVA DEPICTED BY THE RUC AND NGM IS TOO FAR S IN
COMPARISON TO REALITY. AS A RESULT...MOS GUIDANCE IS OVER
FORECASTING THE CLOUD COVER FOR MI EARLY THIS AM. NO ETA AVAILABLE.
WILL ADJUST TIMING OF CLOUDS AND PRECIP BACK A FEW HOURS TO
COMPENSATE FOR THE NGM/REALITY DISCREPANCY.
FOR TODAY...SUFFICIENT LOW LEVEL MOISTURE (I.E. RH OF 70+ PCT) JUST
REACHES THE -10 ISOTHERM ACROSS ERN UPR AND FAR NW LOWER MI IN THE
AFTERNOON...MAINLY LATE FOR FAR NW LOWER MI. WHILE VERTICAL EXTENT
OF MOISTURE MAY BE MARGINAL FOR SIGNIFICANT PRECIP...SUSPECT THESE
AREAS WILL SEE ENOUGH DENDRITIC GROWTH TO WARRANT CHANCE POPS. AREAS
JUST S OF THIS AREA MAY SEE A FEW SPRINKLES LATER IN THE DAY...WHILE SE
SECTIONS OF THE CWA WILL STAY PARTLY SUNNY. MOST LOCATIONS ARE STILL
IN THE 40S ATTM...AND EXPECT TEMPS WILL ONLY RISE A FEW DEGREES
BEFORE CAA STRENGTHENS AND TEMPS BEGIN TO FALL AGAIN TOWARD MIDDAY.
WILL WORD TEMP FORECAST ACCORDINGLY.
FOR TONIGHT AND MONDAY...WINDS SHIFT TO THE N THEN NE BEHIND THE
SECONDARY COLD FRONT AS 850 TEMPS DROP TO AROUND -4 C ACROSS NRN
LAKE MI BY 12Z MON. LACK OF SUFFICIENTLY DEEP MOISTURE WILL ONCE
AGAIN BE THE LIMITING FACTOR...ALTHOUGH DELTA T'S WILL BE CLOSE TO
17 WITH LITTLE IN THE WAY OF AN INVERSION TO CAP OFF LAKE
CONVECTION. BUT WITH LOW LEVEL MOISTURE BEING CONFINED TO BELOW 850
MB...SUSPECT ONLY LAKE CLOUDS AND SOME SCT SPRINKLES/FLURRIES WILL
RESULT TONIGHT INTO MONDAY FOR FAR NE LOWER MI. REST OF THE CWA WILL
SEE A FEW SPRINKLES VIA THE SECONDARY COLD FRONT CONTINUE INTO EARLY
EVENING...THEN PARTIAL CLEAR THEREAFTER AS MID LEVELS DRY AND FLOW
BECOMES INCREASINGLY ANTICYCLONIC.
.APX...NONE.
EME
FXUS63 KDTX 170705 mi
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
945 AM CDT SUN OCT 17 1999
FNT OVR NRN CWA SHD CLR COAST THIS AFTN. STG PRESSURES BEHIND FNT
SHD KEEP IT FROM HANGING UP. CURR PKG HANDLING WELL. WILL JUST MAKE
SOME COSMETIC ADJUSTMENTS TO WORDING. WILL HOLD TSTM MENTION INTO
EARLY PART OF THE AFTN IAH SWD TO GIVE ATMOSPHERE TIME TO STABILIZE
AFTER FROPA. TEMPS SHD NOT RISE MUCH IF AT ALL BEHIND FNT WITH
CAA...PRECIP AND CLDS.
BEST MOISTURE STAYS N AND W OF CWA THRUT FCST PERIOD...CLOSER TO THE
H5 TROF. RUC PRECIP OUTPUT FOR THIS AFTN IS NOT IMPRESSIVE. SO
...UNFORTUNATELY...NOT LOOKING FOR MUCH QPF NEXT 48 HRS.
WINDS QUIET NOW OUT ON THE GULF. SHD COME UP NICELY THIS AFTN AND
EVENING AFTER FROPA WITH STG BL WINDS FCST AND CAA OVR WARM WATER.
.HGX...SCA BAYS AND COASTAL WATERS OUT 50 NM.
46/30/TF
FXUS64 KEPZ 171435 tx
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LUBBOCK TX
1137 AM CDT SUN OCT 17 1999
WATER VAPOR IMAGERY SHOWS UPPER LOW SOUTHWEST OF KABQ WITH ENHANCED
CLOUDS/PRECIPITATION IN DIFLUENT FLOW ALOFT EAST OF THE UPPER LOW.
12Z UPPER AIR ANALYSIS SHOWED 70H LOW OVER THE CENTRAL ARIZONA/NEW
MEXICO STATELINE WITH DECENT WARM ADVECTION OCCURRING OVER THE COLD
POOL AT THE SURFACE. 70H TEMPERATURES WERE COLDER THIS MORNING OVER
THE REGION THAN WHAT WAS PROGGED YESTERDAY. A DOME OF SUBFREEZING
TEMPERATURES AT 85H WAS OVER NORTHEAST NEW MEXICO AND WESTERN TEXAS
PANHANDLE THIS MORNING. RAIN CHANGED OVER TO SNOW OVER THE NORTHWEST
PART OF THE FORECAST AREA BETWEEN 8 AND 9 AM THIS MORNING. THERE HAS
ALSO BEEN SOME ENHANCED REFLECTIVITY ASSOCIATED WITH SLEET SHOWERS
THIS MORNING ALSO. THERE HAVE BEEN REPORTS OF SNOW ACCUMULATION
IN THE WESTERN SOUTH PLAINS ASSOCIATED WITH A PERSISTENT MODERATE
SNOW BAND OVER THIS AREA.
12Z RUC SHOWS THE UPPER LOW WILL MOVE SOUTHEAST TO SOUTH-CENTRAL
NEW MEXICO BY 00Z MONDAY. EXPECT SNOW TO CONTINUE OVER THE NORTHWEST
SOUTH PLAINS THROUGH THE AFTERNOON BEFORE 70H WARM AIR ADVECTION AND
ISENTROPIC LIFT BEGIN TO DIMINISH LATER ON TONIGHT. WILL RECONFIGURE
WINTER WEATHER ADVISORY TO COVER THE NORTHWEST 1/4 OF FORECAST AREA.
WIND SPEEDS HAVE DIMINISHED THIS MORNING AND WILL BACK THEM OFF SOME.
REST OF THE SOUTH PLAINS SHOULD SEE A MIXTURE OF RAIN/SLEET/SNOW BUT
DO NOT EXPECT TO SEE ANY ACCUMULATIONS SO WILL NOT INCLUDE IN
ADVISORY.
.LBB...WINTER WEATHER ADVISORY THIS AFTERNOON ZONES 21>23-27-28-33.
TINSLEY
FXUS64 KEWX 171529 tx