Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 08/25/14
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
550 PM MDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 550 PM MDT SUN AUG 24 2014
SHORT TERM UPDATE WILL BE REQUIRED EARLY THIS EVENING AS
CONVECTION HAS INCREASED ACROSS EAST CENTRAL UTAH. THIS ACTIVITY
MAY EXPAND INTO NW COLORADO...POSSIBLY AS FAR AS A LINE FROM MOAB
TO ASPEN. THIS ACTIVITY IS IN RESPONSE TO EMBEDDED DISTURBANCE
ALONG A SHEAR AXIS THAT CUTS ACROSS THE FORECAST AREA THIS
EVENING. RAP AND HRRR MODELS INDICATE THAT SHOWERS AND STORMS
LASTING WELL BEYOND SUNSET WILL OCCUR FROM VERNAL TO ROUTT COUNTY.
IT APPEARS THAT THE LOWER RESOLUTION SUCH AS THE GFS40 IS
SUGGESTING NOCTURNAL CONVECTION AS WELL. UPDATE WILL BE COMING AND
WILL BE LEANING TOWARDS THE RAP/HRRR MODELS.
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 255 PM MDT SUN AUG 24 2014
12Z H5 HAND ANALYSIS SHOWING A BLOCKING RIDGE EXTENDING FROM THE
GULF STATES UP INTO THE CANADIAN MARITIME REGION. AS SUCH LOW
PRESSURE WILL BE ANCHORING IN THE WESTERN STATES TO START OUT THE
NEW WEEK. THE MORE IMPRESSIVE FEATURES SHOWING UP IN WATER VAPOR
THIS AFTERNOON ARE THE PAIR OF LOWS ROTATING AROUND EACH OTHER OVER
MONTANA AND WASHINGTON THIS AFTERNOON. THE FORMER RETREATING
NORTHEASTWARD AND THE LATTER DROPPING SOUTHWARD WHERE IT WILL CARVE
OUT A FAIRLY AMPLIFIED TROUGH THROUGH THE GREAT BASIN BY EARLY
TUESDAY. DERIVED IMAGERY AND RAOB DATA SHOWS A SIGNIFICANT DECREASE
IN MOISTURE THE PAST 24 HOURS AS THE MONSOONAL PLUME HAS BEEN
DIRECTED INTO THE EASTERN PLAINS. AT GJT AND UPSTREAM PWATS ARE
BELOW NORMAL FOR THIS TIME OF YEAR. THERE ARE SOME RETURNS SHOWING
UP ON RADAR WITH LOW LEVEL MOISTURE...MOUNTAIN CIRCULATIONS AND
INSTABILITY BEING ENHANCED BY A JET ALOFT. THE FOCUS FOR OVERNIGHT
SHOULD MAINLY BE ACROSS THE NORTH WHERE VEERING MID LEVEL PROFILES
AND THE PASSING JET MAXIMA WILL ADD JUST ENOUGH ASCENT TO KEEP
NOCTURNAL CONVECTION FIRING. HAVE THROWN OUT THE AGGRESSIVE GFS
QPF OUTPUT ATTM WITH IT NOT VERIFYING SO FAR THIS AFTERNOON. THETA
SURFACES NEAR 315K SHOW DECENT UPGLIDE NORTH OF INTERSTATE 70
TONIGHT WHILE ALSO HINT AT SOME TAP TO THE TROPICAL MOISTURE LEFT
OVER FROM WHAT IS LEFT OF MARIE. THIS TAP DOES NOT LOOK TO GREATLY
ENHANCE THE MOISTURE ADVECTION TONIGHT BUT MAY PLAY SOME ROLE IN
STORM FORMATION OVER THE EASTERN DIVIDE MOUNTAINS FOR MONDAY.
AGAIN MONDAY LOOKS TO BE SOMEWHAT OF A DOWN DAY AS THE JET ALOFT
WEAKENS AND OVERALL PWATS REMAIN BELOW NORMAL. A SMALL RIBBON OF
THE MOISTURE MENTIONED ABOVE LOOKS TO FAVOR CONVECTION OVER THE
CENTRAL DIVIDE MOUNTAINS UNDER CONFLUENT FLOW ALOFT. THIS ALL
HANDLED WELL IN THE GOING GRID FORECAST SO ONLY SMALL TWEAKS
NEEDED. TEMPERATURES SHOULD BE A BIT MORE MILD OVERNIGHT UNDER WAA
AND PUSH SOME 3 TO 7 DEGREES UPWARD FOR TUESDAY. TUESDAY NIGHT THE
FLOW BACKS MORE SOUTHERLY ALOFT AS THE MAIN TROF AXIS BECOME
ORIENTED MORE MERIDIONALLY. MONSOON AND TROPICAL MOISTURE LOOK TO
BE FORCED NORTHWARD IN THIS FLOW AND THERE SHOULD BE AN INCREASE
IN CONVECTION FROM MIDNIGHT TOWARD SUNRISE...SETTING UP A MORE
ACTIVE DAY FOR TUESDAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 255 PM MDT SUN AUG 24 2014
THE CHALLENGE OF THESE PERIODS HAS BEEN THE TIMING AND THEREFORE
THE PLACEMENT OF THE UPPER LOW THAT WILL DIG OVER THE REGION. THE
EC AND NAM ARE IN GOOD AGREEMENT WITH A SLOWER SOLUTION. THE GFS
AND CANADIAN PRODUCE A FASTER PROGRESSION BUT THE GFS IS SLOWER
THAN ITS PREVIOUS RUNS. AS THE UPPER LOW IS DECOUPLED FROM THE
POLAR FRONT JET...THE SLOWEST EC SOLUTION IS PREFERED. SO
INCREASED STORM COVERAGE AND COOLER TEMPS ARE EXPECTED THROUGH
THURSDAY.
TUESDAY...THE UPPER LOW DUG INTO EASTERN NEVADA ENHANCING A 75KT
JET OVER THIS CWA. MOISTURE SURGES TO OVER AN INCH PRECIPITABLE
WATER VALUES IN SE UTAH. WEDNESDAY THE UPPER LOW SLOWLY PROGRESSES
INTO NE UTAH LOSING JET SUPPORT BUT GAINING CYCLONIC AND DIVERGENT
FLOW ALOFT. PRECIP WATER VALUES REMAIN NEAR ONE INCH. STORM MOTION
ALSO REMAINS BRISKLY TO THE NE AT 20 KTS LIMITING RAINFALL FORM
ANY SINGLE STORM. BY THURSDAY THE LOW CENTER AMBLES TO THE
CONTINENTAL DIVIDE WITH WRAP-AROUND DYNAMICS ACROSS THE NORTHERN
CWA AND THE UPPER FLOW SWITCHING TO NW. SOME NOCTURNAL STORMS ARE
EXPECTED THROUGH THESE PERIODS.
BY FRIDAY THE EC PROGRESSES THE OPENING LOW ONTO THE EASTERN
PLAINS WITH A RIDGE BUILDING IN FROM THE WEST. FRIDAY STORM
ACTIVITY WILL LINGER ALONG THE CONTINENTAL DIVIDE...THEN A DRYING
AND WARMING TREND INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 550 PM MDT SUN AUG 24 2014
EVENING NOCTURNAL SHRA/TSRA WILL BE POSSIBLE ACROSS NE UTAH INTO
NW COLORADO...THIS INCLUDES THE TAF SITE AT KVEL WITH TSRA IN THE
VICINITY OF KGJT AND KRIL. CELLS WILL BE MOVING WSW TO ENE AT
ABOUT 20 KNOTS. LOCALIZED WIND GUSTS OF 25-35KTS WILL BE POSSIBLE
FROM NEARBY CELLS. CONVECTIVE TURBULENCE IS LIKELY.
BETWEEN 12Z-18Z...MINIMAL AVIATION HAZARDS EXPECTED.
AFTER 18Z...SCATTERED SHRA/TSRA WILL FORM...PRIMARILY OVER THE
MOUNTAINS OF NE UTAH AND WRN COLORADO. THUNDERSTORMS WILL BE IN
THE VICINITY OF THESE TAF SITES.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...PF
SHORT TERM...15
LONG TERM...JOE
AVIATION...PF
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
327 AM MDT SAT AUG 23 2014
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 319 AM MDT SAT AUG 23 2014
A RATHER STG UPPER LEVEL TROUGH WILL MOVE ACROSS THE NRN ROCKIES
THRU TONIGHT WITH COLORADO BEING ON THE SRN EDGE OF THE TROUGH.
MEANWHILE AN UPPER LEVEL JET WILL REMAIN ACROSS NRN PORTIONS OF THE
AREA THRU THIS EVENING WITH SOME POTENTIAL VORTICITY IN THE MID TO
UPPER LEVELS. THUS SHOULD SEE A GOOD CHC OF SHOWERS AND TSTMS IN
THE MTNS LATER THIS MORNING INTO THE AFTN HOURS. OVER NERN CO LOW
LVL MOISTURE WILL MIX OUT SOME THRU THE DAY EXCEPT OVER THE FAR
NERN PLAINS. CAPES WILL RANGE FM 500-1000 J/KG ALONG THE FRONT
RANGE WHILE OVER THE FAR NERN PLAINS VALES WILL BE ABOVE 1500 J/KG.
AS OUTFLOW BOUNDARIES FM CONVECTION OVER THE HIGHER TERRAIN MOVE
ACROSS BY EARLY TO MID AFTN EXPECT SCT TSTMS TO DVLP ALONG THE
FRONT RANGE AND THEN MOVE RATHER QUICKLY ACROSS THE PLAINS FM
LATE AFTN INTO THE EARLY EVEING HOURS. WITH RATHER STG MID LVL FLOW
A FEW STORMS COULD PRODUCE WIND GUSTS UP TO 60 MPH. OVER THE FAR
NERN PLAINS WHERE CAPES WILL BE BETTER SOME MARGINAL LARGE HAIL
COULD OCCUR AS WELL. AS FOR HIGHS WILL KEEP READINGS MOSTLY IN THE
LOWER TO MID 80S ACROSS NERN CO.
BY THIS EVENING AS DRIER AIR BEGINS TO SPREAD INTO THE MTNS PRECIP
SHOULD GRADUALLY DECREASE OVER THE HIGHER TERRAIN. OVER NERN CO
PCPN CHANCES SHOULD END BY EARLY EVENING ALONG THE FRONT RANGE AND
THEN BY MIDNIGHT OVER THE FAR NERN CORNER.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 319 AM MDT SAT AUG 23 2014
SUNDAY AND SUNDAY NIGHT...THE FLOW ALOFT REMAIN SOUTHWESTERLY.
ENOUGH SUBTROPICAL MOISTURE WILL BE AROUND VIA THE GFS/ECMWF
MODELS TO KEEP A CHANCE OF TSTMS IN THE AFTN/EVNG. THE BEST CHC
WL BE OVER THE MOUNTAINS. ON MONDAY...THE NEXT SYSTEM WILL
APPROACH CO FM THE NORTHWEST...WITH A SOUTHWESTERLY FLOW AHEAD OF
IT. THUNDERSTORMS WILL AGAIN DEVELOP OVER THE CWFA MONDAY
AFTN/EVNG WITH THE TROUGH ITSELF STILL OVER SRN ID/NRN UT BY 12Z
TUESDAY. THE ECMWF/NAM ARE SLOER THAN THE MORE PROGRESSIVE GFS
WHICH MAINTAINS AN OPEN WAVE TROUGH...THE NAM DRIVES A CLOSED
CIRCULATION INTO NORTHERN CA. THE ECMWF IS THE COMPROMISE
MDL...IT CLOSES THE UPPER LOW BUT STILL SHIFTS IT EASTWARD ACROSS
COLORADO...BUT SLOER...TUESDAY INTO WEDNESDAY. WL FOLLOW THIS
PLAN FOR NOW AT BUMP THE POPS UPWARD FOR TUESDAY NIGHT AND
WEDNESDAY. THURSDAY AND FRIDAY...WL CONTINUE WITH THE TREND OF
DRIER AND WARMER WITH A RIDGE PROGGED TO BUILD OVER THE WESTERN
U.S.
&&
.AVIATION...(FOR THE TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 319 AM MDT SAT AUG 23 2014
TRICKY FCST FOR THIS MORNING DUE TO POTENTIAL FOG AS TEMP-DEWPOINT
SPREADS ARE LOW AND WINDS ARE LIGHT. HRRR HAS BEEN ALTERNATING
BETWEEN DENSE FOG AND NO DENSE FOG WITH EACH SUCCESSIVE RUN WHILE
THE RAP HAS SHOWN NOTHING THE ENTIRE TIME. THE HRRR DOES SHOW SOME
TYPE OF WK CYCLONE DEVELOPING NR DIA WITH WINDS BECOMING LIGHT NNW
AROUND 12Z. IF THIS HAPPENS THEN POTENTIAL FOR DENSE FOG WOULD
INCREASE IN THE 12Z-15Z TIME PERIOD. DUE TO UNCERTAINTY OF FCST
WILL INTRODUCE A TEMPO GROUP FOR IFR CONDITIONS.
FOR THIS AFTN OUTFLOW BOUNDARIES FM MTN CONVECTON WILL PUSH ACROSS
BY 21Z WHICH MAY TRIGGER SCT TSTMS. WITH DECENT MID LVL FLOW THE
STORMS WILL BE QUICK MOVING BUT COULD PRODUCE WIND GUSTS FM 40-50
MPH. ALSO WITH UPPER LEVEL JET OVERHEAD THIS IS SOME POSSIBILITY
FOR STORM REGENERATION INTO THE EARLY EVENING HOURS THRU 02Z. BY
MID EVENING THREAT OF STORMS SHOULD END. WINDS WILL BE ESE BY
MIDDAY AND THEN SWITCH TO THE WNW BY 21Z AS INITIAL OUTFLOW
BOUNDARIES MOVE ACROSS. BY EARLY EVENING WINDS WILL BE LIGHT NNW
AND THEN TRANSITION TO DRAINAGE BY 06Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM...COOPER
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS ALBANY NY
422 PM EDT SAT AUG 23 2014
.SYNOPSIS...
HIGH PRESSURE WILL GRADUALLY TAKE HOLD ACROSS THE REGION
TONIGHT INTO SUNDAY. THIS HIGH PRESSURE SYSTEM WILL REMAIN OVER THE
EASTERN SEABOARD INTO THE MIDDLE OF THE UPCOMING WEEK...BRINGING
WARM AND DRY SUMMER WEATHER TO THE ALBANY FORECAST AREA.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
CLOUDS ARE HANGING TOUGH ACROSS THE FORECAST AREA THIS AFTERNOON.
SURFACE WINDS ARE LIGHT AND GENERALLY FROM THE NORTHEAST.
TEMPERATURES RANGE FROM THE 60S IN THE HILLS TO THE 70S IN THE
VALLEYS. RADAR SHOWS A FEW VERY LIGHT SHOWERS OR SPRINKLES
SCATTERED ACROSS THE AREA.
LATEST 17Z RAP MODEL SHOWS LOW CLOUDS LINGERING UNTIL
SHORTLY AFTER MIDNIGHT TONIGHT. HI-RES RAPID REFRESH MODEL SHOWS A
SLIGHT CHANCE OF A SHOWER CONTINUING UNTIL SUNSET. THE HI-RES WRF
AGREES WITH THE THREAT FOR ANY SHOWERS ENDING AFTER SUNSET.
SKIES SHOULD GRADUALLY CLEAR OVERNIGHT...AND BASED ON
TEMP/DEWPOINT/WINDS FORECAST OVERNIGHT...EXPECT AREAS OF FOG TO
FORM IN THE VALLEYS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
FOG AND/OR LOW CLOUDINESS WILL DISSIPATE SUNDAY MORNING LEAVING A
MOSTLY SUNNY DAY. SOME AFTERNOON CLOUDS MAY DEVELOP OVER THE
HIGHER TERRAIN WITH THE HEATING FROM THE SUN. MODELS HAVE THE AREA
DRY TOMORROW SO KEPT POPS BELOW 15 PERCENT. HIGHS ON SUNDAY WILL
RANGE FROM THE MID 70S IN THE HILLS TO LOW 80S IN THE VALLEYS.
SUNDAY NIGHT...MOSTLY CLEAR SKIES AND LIGHT WINDS WILL LEAD TO
THE DEVELOPMENT OF VALLEY FOG. IT IS THE BEGINNING OF FOG SEASON
AND CONDITIONS LOOK GOOD AGAIN FOR VALLEY FOG FORMATION.
THIS FOG WILL DISSIPATE MONDAY MORNING LEAVING A MOSTLY SUNNY AND
WARM DAY. EXPECT MONDAY TO BE DRY UNDER HIGH PRESSURE. HIGHS
MONDAY IN THE UPPER 70S HILLS TO MID 80S VALLEYS.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL REMAIN AT ALL LEVELS OF THE ATMOSPHERE...THROUGH
EARLY WEDNESDAY. THIS WILL CONTINUE OUR TRANQUIL LATE SUMMER WEATHER
WITH SLIGHTLY ABOVE NORMAL TEMPERATURES ALONG WITH A GOOD DEAL OF
SUNSHINE.
WEDNESDAY INTO THURSDAY....IT LOOKS AS IF A WEAK COLD FRONT WILL
CROSS THE REGION WITH PERHAPS A FEW SHOWERS AND THUNDERSTORMS...BUT
WITH WEAK FORCING...CONVECTION COULD BE FAR AND FEW BETWEEN.
THE FRONT HOWEVER...LOOKS TO GET HUNG UP SOMEWHERE OVER OUR REGION
OR A LITTLE SOUTH OF IT. IT COULD COME BACK AS A WARM FRONT...WHILE
PERHAPS A STRONGER COLD FRONT ATTEMPTS TO MAKE IT THROUGH ON
SATURDAY OR SUNDAY WITH A BETTER CHANCE OF SHOWERS AND
THUNDERSTORMS.
THE TROPICS CONTINUE TO TRY TO FLARE UP. WE COULD HAVE OUR THIRD
TROPICAL NAMED STORM...WHICH WOULD BE NAMED CRISTOBAL BY SUNDAY.
ALMOST ALL GUIDANCE KEEPS THIS STORM SOUTH AND EAST OF OUR REGION.
HOWEVER...THERE COULD BE SOME INDIRECT IMPACTS OF THIS
STORM...PERHAPS YIELDING A PREDECESSOR RAIN EVENT (PRE) OVER OR NEAR
REGION NEXT WEEKEND...FOCUSED ON EITHER THE WARM OR COLD FRONT. THE
TROPICAL SYSTEM COULD ALSO PUMP THE RIDGE OVER US...BLOCKING ANY
COLD FRONT FROM MOVING SOUTH.
BOTTOM LINE...THE EXTENDED PERIOD STARTS WARM AND DRY...BECOMING
MORE UNCERTAIN WITH TIME BUT LIKELY TEMPERATURES STAYING AT OR EVEN
A LITTLE ABOVE NORMAL. HUMIDITY WILL START OUT MODERATE (DEWPOINTS
AROUND 60) PERHAPS CREEPING INTO THE 60S WITH TIME.
LOOK FOR HIGHS GENERALLY IN THE 80S IN THE VALLEYS (75-80 HIGHER
TERRAIN) THROUGHOUT THE PERIOD...LOWS WILL RANGE FROM THE UPPER 50S
TO MID 60S.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
LOOKING AT VFR CONDITIONS THROUGH MOST OF THE EVENING.
THEN...AS TEMPERATURES FALL TO THE FORECAST "CROSSOVER" TEMPERATURES
IN THE LOWER 50S...ALONG WITH A SOMEWHAT DAMP GROUND FROM ALL THE
THURSDAY AND FRIDAY/S RAINFALL...NO WIND AND INITIALLY FEW IF ANY
SENSIBLE CLOUDS...FOG WILL LIKELY FORM AT ALL THE TAF SITES DURING
THE OVERNIGHT PERIOD.
WE BELIEVE THE FOG WILL BE MAINLY IFR (2SM BR) AT KGFL AND
KPSF...BEGINNING AT 06Z AND 08Z RESPECTIVELY. AT THE TWO OTHER
SITES SINCE TEMPERATURES ARE PROJECTED NOT TO GET AS LOW...WE WENT
WITH MVFR MIST (3SM BR)..AFTER 08Z. WE ALSO INCLUDE IFR CIGS AT KGFL
AND KGFL AS THE FOG COULD ACTUALLY GET RATHER DEEP.
IT LOOKS AS IF THE FOG SHOULD BURN OFF BETWEEN 1130Z-1200Z ON
SUNDAY. AFTER THAT...NO AVIATION WEATHER RELATED PROBLEMS ARE
EXPECTED ON SUNDAY WITH GOOD VISIBILITY AND ONLY FEW-SCT CU AT THE
5-6KFT.
THE N-NE 5-10KT SURFACE WIND SHOULD BECOME CALM TONIGHT...THEN
5-10KTS ON SATURDAY.
OUTLOOK...
SUNDAY NIGHT: NO OPERATIONAL IMPACT. AREAS FG.
MONDAY: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. SLIGHT CHANCE OF
SHRA...TSRA.
THURSDAY: MODERATE OPERATIONAL IMPACT. SLIGHT CHANCE OF
SHRA...TSRA.
&&
.FIRE WEATHER...
RH VALUES WILL RISE TO NEAR 100 PERCENT OVERNIGHT WITH GRADUALLY
CLEARING SKIES. EXPECT AREAS OF VALLEY FOG AND WIDESPREAD DEW TO
FORM OVERNIGHT. WINDS WILL BE LIGHT AND VARIABLE.
ON SUNDAY RH VALUES DROP TO BETWEEN 40 AND 50 PERCENT UNDER PARTLY
SUNNY SKIES. WINDS WILL BE LIGHT AND FROM THE NORTHEAST.
RH VALUES WILL INCREASE TO NEAR 100 PERCENT SUNDAY NIGHT WITH
LIGHT AND VARIABLE WINDS. AREAS OF VALLEY FOG AND WIDESPREAD DEW
WILL FORM AGAIN. WINDS WILL BE LIGHT AN VARIABLE.
&&
.HYDROLOGY...
NO HYDROLOGIC ISSUES ARE EXPECTED THROUGH THE NEXT FIVE DAYS.
LITTLE PRECIPITATION IS EXPECTED. RIVER AND LAKE LEVELS WILL
GRADUALLY RECEDE DURING THE PERIOD.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...SND
NEAR TERM...SND
SHORT TERM...SND
LONG TERM...HWJIV
AVIATION...HWJIV
FIRE WEATHER...SND
HYDROLOGY...SND
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
233 PM EDT SAT AUG 23 2014
...HEAT ADVISORY ALL AREAS REST OF TODAY...
.CURRENTLY...A SCT-BKN CU FIELD HAS DEVELOPED IN PREVAILING NWLY
FLOW WITH A VERY HOT DAY ONGOING. A FEW OBS SHOW UPPER 90S AND 100
AT THIS TIME WITH A FEW HEAT INDICES OF AROUND 110 BEING
REPORTED. SOME LOW LEVEL MIXING WILL CONTINUE AND HELP LIMIT HEAT
INDICES SOMEWHAT. RAP SOUNDING SHOW A VERY DRY AIRMASS UNDER CLOUD BASES
OVER SE GA AND MORE MOIST OVER NE FL WHERE PWATS ARE ABOUT 1.8
INCHES. A FEW SHOWERS HAVE POPPED OVER INLAND AREAS AND ALONG THE
E COAST. AS EXPECTED THE E COAST SEA BREEZE IS STILL VERY NEAR THE
COAST...BUT WILL CONTINUE TO MAKE A SLOW AND STEADY PROGRESS
INLAND. FOR REST OF THE AFTN...ISOLD TO SCT SHOWERS AND STORMS
WILL DEVELOP WITH THE BEST CHANCES GENERALLY OVER THE SRN 2/3RDS
OF THE AREA. CONVECTION WILL LIKELY END BY AROUND MIDNIGHT TO 1 AM
FOR MY INLAND NE FL ZONES. AN ISOLD STRONG STORM IS POSSIBLE.
REST OF TONIGHT...MUGGY OVERNIGHT LOWS IN THE MID TO LOCALLY UPPER
70S WITH LIGHT WINDS.
.SHORT TERM...FRONTAL BOUNDARY WILL SINK SOUTH TO NEAR FL/GA LINE
BY SUNDAY AFTERNOON...THEN INTO CENTRAL FL SUNDAY NIGHT. THIS
BOUNDARY WILL BE A FOCUS FOR SHOWERS/STORMS AS IT PASSES. THE
BOUNDARY SHOULD REACH SE GA COUNTIES SUNDAY MORNING...THEN SINK
SOUTH OF FORECAST AREA AROUND MIDNIGHT SUNDAY NIGHT. HIGH PRESSURE
WILL PUSH SOUTH BEHIND THIS BOUNDARY...WHICH WILL LIMIT
PRECIPITATION POTENTIAL ON MONDAY. WILL HAVE PRECIPITATION OVER
NORTHEAST FLORIDA...DUE TO POSSIBLE OUTER MOISTURE BANDS FROM
POTENTIAL TROPICAL SYSTEM.
TEMPERATURES WILL BE A FEW DEGREES COOLER ON SUNDAY DUE TO CLOUDS AND
PRECIPITATION COVERAGE. WITH INCREASING ONSHORE FLOW...MOST LOCATIONS
WILL LIKELY REMAIN AT OR BELOW 90 ON MONDAY.
.LONG TERM.../MONDAY NIGHT THROUGH SATURDAY/...
THE FORECAST DURING THIS PERIOD WILL BE DRIVEN BY THE POTENTIAL FOR
A TROPICAL SYSTEM TO FORM. AT THIS TIME...INDICATIONS CONTINUE TO BE
FOR THIS SYSTEM TO PASS TO THE EAST OF THE AREA. WITH THIS...COULD
HAVE PRECIPITATION OVER EASTERN COUNTIES...WITH MAINLY DRY
CONDITIONS FURTHER INLAND. WITH THE FORECAST TRACK FOR THIS
POTENTIAL TROPICAL SYSTEM STILL BEING UNCERTAIN...HAVE KEPT WITH
CURRENT FORECAST GRIDS FOR THIS PERIOD.
MAX TEMPERATURES WILL LIKELY BE A FEW DEGREES BELOW NORMAL THROUGH
MID WEEK...THEN RETURN TO NEAR TO ABOVE NORMAL LATER IN THE PERIOD.
&&
.AVIATION...INCLUDED VCSH FOR NOW FOR FL TAFS WITH VCTS BEGINNING
IN A COUPLE OF HOURS. STILL LOOKS LIKE BEST CHANCE OF TSTM
OCCURRING AT GNV SO INSERTED TEMPO GROUP 21Z-24Z. VFR SHOULD
PREVAILING AFTER 00Z.
&&
.MARINE...SELY WINDS THIS EVENING WILL TURN BACK TO THE W BY SUN
MORNING. NORTHEAST WINDS WILL BEGIN TO INCREASE ON SUNDAY BEHIND
A BACKDOOR COLD FRONT WITH AN EXTENDED PERIOD OF ONSHORE FLOW
EXPECTED THROUGH THE MIDDLE OF NEXT WEEK. SMALL CRAFT ADVISORY
CONDITIONS WILL BE POSSIBLE EARLY NEXT WEEK AS THE PRESSURE
GRADIENT TIGHTENS WITH HIGH PRESSURE BUILDING DOWN THE COAST AND A
POSSIBLE TROPICAL SYSTEM PASSING OVER THE WRN ATLC WATERS BUT
LARGE UNCERTAINTY REMAINS ON THE EXACT TRACK. SEAS WILL BE
DEPENDENT ON STRENGTH AND TRACK OF ANY TROPICAL SYSTEM BUT FOR NOW
GIVEN THE CONSIDERABLE DEGREE OF UNCERTAINTY WE WILL CAP THE SEAS
AT 7 FT.
RIP CURRENTS: LOW RISK TODAY THEN MODERATE RISK EXPECTED TOMORROW
AS ONSHORE FLOW DEVELOPS.
&&
.CLIMATE...
A FEW RECORD HIGHS ARE EXPECTED TO AT LEAST BE TIED TODAY.
RECORD HIGHS TODAY
JAX 98/1966
GNV 99/1902
AMG 99/1968
SSI 95/2006
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 75 96 75 91 / 10 40 40 10
SSI 79 88 77 85 / 20 30 40 40
JAX 76 94 77 88 / 20 30 40 40
SGJ 76 90 78 87 / 10 20 40 40
GNV 75 95 73 88 / 30 50 50 20
OCF 75 95 74 89 / 30 50 50 30
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ALACHUA-BAKER-
BRADFORD-CLAY-COLUMBIA-DUVAL-FLAGLER-GILCHRIST-HAMILTON-
MARION-NASSAU-PUTNAM-ST JOHNS-SUWANNEE-UNION.
GA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR APPLING-ATKINSON-
BACON-BRANTLEY-CHARLTON-CLINCH-COASTAL CAMDEN-COASTAL GLYNN-
COFFEE-ECHOLS-INLAND CAMDEN-INLAND GLYNN-JEFF DAVIS-PIERCE-
WARE-WAYNE.
AM...NONE.
&&
$$
SHASHY/STRUBLE/GUILLET
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
957 AM EDT SAT AUG 23 2014
UPDATE... HIGH PRESSURE ALOFT AND AT THE SURFACE WILL CONTINUE
ACROSS THE REGION TODAY. LATEST RUNS OF THE HRRR KEEP CONVECTION
VERY SPARSE ACROSS THE CWFA TODAY...AND LOW END SCT/ISOLD POPS
STILL LOOK GOOD. DO THINK ANY CONVECTIVE ACTIVITY THAT DOES
DEVELOP WILL BE TERRAIN BASED...OR DEPENDENT UPON ANY MESOSCALE
BOUNDARIES.
MODIFIED SOUNDING DOES SHOW SOME VERY GOOD SURFACE INSTABILITY
PRESENT. SOUNDING ALSO ALSO SHOWS PLENTY OF DRY AIR ALOFT. SO...IF
THUNDERSTORMS ARE ABLE TO DEVELOP...THEY WOULD LIKELY BE ABLE TO
PRODUCE GUSTY WINDS AND FREQUENT LIGHTNING STRIKES. ISOLD SEVERE
IS POSSIBLE...BUT THE POTENTIAL REMAINS LOW DUE TO VERY LITTLE
CONVECTIVE COVERAGE EXPECTED.
WILL ALSO BE EXTENDING THE HEAT ADVISORY NORTHWARD ON THE SW SIDE.
PREV DISCUSSION... /ISSUED 721 AM EDT SAT AUG 23 2014/
SHORT TERM /TODAY THROUGH SUNDAY/...
/ISSUED AT 347 AM EDT SAT AUG 23 2014/
BIG CHANGES ON TAP THROUGH THE SHORT TERM PERIOD AS MODELS CONTINUE
TO SHOW JUST ONE MORE HOT DAY BEFORE A WELCOMED BACK DOOR COLD FRONT
SWEEPS ACROSS THE AREA ON SUNDAY. FOR TODAY... THE DOMINATING UPPER
RIDGE BEGINS TO RETREAT WESTWARD AS A SERIES OF DISTURBANCES TRACK
DOWN THE EASTERN PERIPHERY AND ACROSS THE STATE DURING THE AFTERNOON
AND OVERNIGHT HOURS. THIS WILL WARRANT SHOWING A BETTER CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH AND EAST CENTRAL PORTIONS
OF THE FORECAST AREA TODAY... AND HOLDING ONTO A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS FOR ALL AREAS TONIGHT. THE CONTINUED HEAT
AND STRONG INSTABILITY COUPLED WITH SOME UPPER SUPPORT SUGGEST THE
POTENTIAL FOR A FEW STRONG TO POSSIBLY SEVERE STORMS LATER THIS
AFTERNOON AND EARLY EVENING... WITH STRONG TO POTENTIALLY DAMAGING
WINDS BEING THE MAIN CONCERN FOR LATER TODAY. NOTHING WIDESPREAD IS
EXPECTED... JUST CANNOT RULE OUT THIS POSSIBILITY AS AFTERNOON
SBCAPE VALUES CLIMB BACK INTO THE 3000-4000 J/KG RANGE...ESPECIALLY
ACROSS CENTRAL GA.
AS FOR THE HEAT... AREA TEMPS ARE EXPECTED TO PUSH WELL INTO THE 90S
AGAIN TODAY FOR MOST AREAS... ESPECIALLY ACROSS CENTRAL GA WHERE
NEAR 100 DEGREE TEMPS WILL ONCE AGAIN BE FELT DURING MAX DAYTIME
HEATING. THIS WILL PUSH HEAT INDEX VALUES NEAR OR ABOVE THE CRITICAL
105 DEGREE MARK FOR AREAS GENERALLY ALONG AND SOUTH OF LUMPKIN TO
FORSYTH TO ATHENS LINE WHERE A HEAT ADVISORY IS CURRENTLY IN EFFECT.
SEE NO REASON TO CHANGE THE ADVISORY AS CURRENTLY POSTED.
THE BIG CHANGE WILL COME ON SUNDAY AS A COLD FRONT PUSHES DOWN FROM
THE NORTHEAST AND PUSHES SOUTH OF COLUMBUS AND MACON BY SUNDAY
EVENING. THIS WILL SPREAD CLOUDS AND INCREASING RAIN CHANCES ACROSS
THE AREA... BUT MORE IMPORTANTLY... BRING MUCH RELIEF FROM THE HEAT
AS SUNDAY AFTERNOON TEMPS STRUGGLE TO GET INTO THE 90S FOR MOST
AREAS. ALTHOUGH SUSPECT THE CONVECTION ON SUNDAY WILL LIKELY BE
MOSTLY SHOWERS... MODELS CONTINUE TO SHOW 1000-2000 J/KG OF CAPE
AHEAD AND BEHIND THE FRONT SUNDAY AFTERNOON... SO WILL CONTINUE TO
WORD FOR A CHANCE OF THUNDERSTORMS AS WELL. HOWEVER... NOTHING
SEVERE IS EXPECTED AT THIS TIME.
39
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
/ISSUED AT 347 AM EDT SAT AUG 23 2014/
UPPER RIDGE CONTINUES TO DOMINATE AT THE BEGINNING OF THE
EXTENDED...WHILE SFC RIDGE BUILDS ACROSS THE MID ATLANTIC AND DOWN
THE APPALACHIANS. WITH THE PSEUDO WEDGE BUILDING IN...WINDS BECOME
EASTERLY AND CLOUD COVERAGE REMAINS BKN AT LEAST INITIALLY. CLOUD
COVERAGE DOES HELP TO KEEP TEMPS ON THE COOLER SIDE ON MONDAY.
DRIER AIR MOVES IN FOR THE FIRST HALF OF THE WEEK /BEHIND THE
BACKDOOR FRONT/. WITH THIS...DO NOT HAVE MOISTURE AROUND FOR MUCH
IN TERMS OF PRECIP AND THUS HAVE LIMITED POPS TO NO MENTION OR
SLIGHT CHANCE. DIFFERENCES EXIST BETWEEN THE GFS AND ECMWF IN THE
SECOND HALF THE OF THE EXTENDED. GFS BRINGS A COLD FRONT INTO THE
AREA ON FRIDAY...WHILE THE ECMWF KEEPS AN UPPER RIDGE ACROSS THE
SOUTHEAST. HAVE TENDED MORE TOWARDS THE GFS AND SHOWN AN INCREASE
IN CLOUDS/PRECIP FOR FRIDAY ASSOCIATED WITH THE FRONT.
DIFFERENCES ALSO EXIST STILL WITH HOW THE MODELS ARE HANDLING THE
POTENTIAL TROPICAL SYSTEM NEXT WEEK. GFS REMAINS FURTHER WEST AND
SLOWER WHILE THE ECMWF IS FURTHER EAST /ALTHOUGH LATEST RUN IS
WEST OF PREVIOUS RUN/ AND FASTER. NEITHER 00Z SOLUTION BRINGS
IMPACTS TO THE CWA...BUT REGARDLESS...STILL FAR OUT IN THE
FORECAST AND ITS SOMETHING THAT NEEDS TO BE WATCHED AS WE HEAD
INTO NEXT WEEK.
11
AVIATION...
12Z UPDATE...
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD DESPITE A
BIG CHANGE IN OVERALL WEATHER PATTERN. HIGH PRESSURE WEAKENS ITS
GRIP TODAY... ALLOWING SLIGHTLY BETTER CHANCE FOR SCT AFTERNOON
THUNDERSTORMS. THEN A BACKDOOR COLD FRONT SWEEPS ACROSS THE AREA
EARLY ON SUN... BRINGING MID LEVEL CIGS AND SCT TO NUMEROUS SHOWERS
WITH SOME EMBEDDED THUNDERSTORMS TO THE AREA EARLY ON SUN. WILL SHOW
TEMPO -TSRA 19-23Z TODAY... THEN PROB30 -SHRA 12-18Z SUN WITH THE
FRONT. CURRENT NW WINDS PERSIST TODAY AROUND 8-11KTS... THEN SHIFT
NE AROUND 08-10Z SUN WITH SPEEDS AROUND 10-12KTS ON SUN.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM ON ALL ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 97 73 88 70 / 30 30 60 30
ATLANTA 93 75 90 72 / 30 20 60 40
BLAIRSVILLE 88 69 83 67 / 30 30 60 40
CARTERSVILLE 94 71 89 72 / 30 20 60 40
COLUMBUS 98 75 94 75 / 20 20 60 40
GAINESVILLE 94 73 87 71 / 30 30 60 40
MACON 99 73 93 72 / 20 20 60 40
ROME 95 71 91 73 / 30 20 60 40
PEACHTREE CITY 94 71 90 72 / 20 20 60 40
VIDALIA 99 75 94 74 / 20 20 60 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BALDWIN...BIBB...BLECKLEY...CLARKE...CRAWFORD...CRISP...
DODGE...DOOLY...EMANUEL...GLASCOCK...GREENE...HANCOCK...
HOUSTON...JASPER...JEFFERSON...JOHNSON...JONES...LAURENS...
MACON...MONROE...MONTGOMERY...MORGAN...OCONEE...OGLETHORPE...
PEACH...PULASKI...PUTNAM...SCHLEY...STEWART...SUMTER...
TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TREUTLEN...TWIGGS...
WARREN...WASHINGTON...WEBSTER...WHEELER...WILCOX...WILKES...
WILKINSON.
&&
$$
SHORT TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
947 AM EDT SAT AUG 23 2014
.UPDATE...
HIGH PRESSURE ALOFT AND AT THE SURFACE WILL CONTINUE ACROSS THE
REGION TODAY. LATEST RUNS OF THE HRRR KEEP CONVECTION VERY SPARSE
ACROSS THE CWFA TODAY...AND LOW END SCT/ISOLD POPS STILL LOOK
GOOD. DO THINK ANY CONVECTIVE ACTIVITY THAT DOES DEVELOP WILL BE
TERRAIN BASED...OR DEPENDENT UPON ANY MESOSCALE BOUNDARIES.
MODIFIED SOUNDING DOES SHOW SOME VERY GOOD SURFACE INSTABILITY
PRESENT. SOUNDING ALSO ALSO SHOWS PLENTY OF DRY AIR ALOFT. SO...IF
THUNDERSTORMS ARE ABLE TO DEVELOP...THEY WOULD LIKELY BE ABLE TO
PRODUCE GUSTY WINDS AND FREQUENT LIGHTNING STRIKES. ISOLD SEVERE
IS POSSIBLE...BUT THE POTENTIAL REMAINS LOW DUE TO VERY LITTLE
CONVECTIVE COVERAGE EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 721 AM EDT SAT AUG 23 2014/
SHORT TERM /TODAY THROUGH SUNDAY/...
/ISSUED AT 347 AM EDT SAT AUG 23 2014/
BIG CHANGES ON TAP THROUGH THE SHORT TERM PERIOD AS MODELS CONTINUE
TO SHOW JUST ONE MORE HOT DAY BEFORE A WELCOMED BACK DOOR COLD FRONT
SWEEPS ACROSS THE AREA ON SUNDAY. FOR TODAY... THE DOMINATING UPPER
RIDGE BEGINS TO RETREAT WESTWARD AS A SERIES OF DISTURBANCES TRACK
DOWN THE EASTERN PERIPHERY AND ACROSS THE STATE DURING THE AFTERNOON
AND OVERNIGHT HOURS. THIS WILL WARRANT SHOWING A BETTER CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE NORTH AND EAST CENTRAL PORTIONS
OF THE FORECAST AREA TODAY... AND HOLDING ONTO A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS FOR ALL AREAS TONIGHT. THE CONTINUED HEAT
AND STRONG INSTABILITY COUPLED WITH SOME UPPER SUPPORT SUGGEST THE
POTENTIAL FOR A FEW STRONG TO POSSIBLY SEVERE STORMS LATER THIS
AFTERNOON AND EARLY EVENING... WITH STRONG TO POTENTIALLY DAMAGING
WINDS BEING THE MAIN CONCERN FOR LATER TODAY. NOTHING WIDESPREAD IS
EXPECTED... JUST CANNOT RULE OUT THIS POSSIBILITY AS AFTERNOON
SBCAPE VALUES CLIMB BACK INTO THE 3000-4000 J/KG RANGE...ESPECIALLY
ACROSS CENTRAL GA.
AS FOR THE HEAT... AREA TEMPS ARE EXPECTED TO PUSH WELL INTO THE 90S
AGAIN TODAY FOR MOST AREAS... ESPECIALLY ACROSS CENTRAL GA WHERE
NEAR 100 DEGREE TEMPS WILL ONCE AGAIN BE FELT DURING MAX DAYTIME
HEATING. THIS WILL PUSH HEAT INDEX VALUES NEAR OR ABOVE THE CRITICAL
105 DEGREE MARK FOR AREAS GENERALLY ALONG AND SOUTH OF LUMPKIN TO
FORSYTH TO ATHENS LINE WHERE A HEAT ADVISORY IS CURRENTLY IN EFFECT.
SEE NO REASON TO CHANGE THE ADVISORY AS CURRENTLY POSTED.
THE BIG CHANGE WILL COME ON SUNDAY AS A COLD FRONT PUSHES DOWN FROM
THE NORTHEAST AND PUSHES SOUTH OF COLUMBUS AND MACON BY SUNDAY
EVENING. THIS WILL SPREAD CLOUDS AND INCREASING RAIN CHANCES ACROSS
THE AREA... BUT MORE IMPORTANTLY... BRING MUCH RELIEF FROM THE HEAT
AS SUNDAY AFTERNOON TEMPS STRUGGLE TO GET INTO THE 90S FOR MOST
AREAS. ALTHOUGH SUSPECT THE CONVECTION ON SUNDAY WILL LIKELY BE
MOSTLY SHOWERS... MODELS CONTINUE TO SHOW 1000-2000 J/KG OF CAPE
AHEAD AND BEHIND THE FRONT SUNDAY AFTERNOON... SO WILL CONTINUE TO
WORD FOR A CHANCE OF THUNDERSTORMS AS WELL. HOWEVER... NOTHING
SEVERE IS EXPECTED AT THIS TIME.
39
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
/ISSUED AT 347 AM EDT SAT AUG 23 2014/
UPPER RIDGE CONTINUES TO DOMINATE AT THE BEGINNING OF THE
EXTENDED...WHILE SFC RIDGE BUILDS ACROSS THE MID ATLANTIC AND DOWN
THE APPALACHIANS. WITH THE PSEUDO WEDGE BUILDING IN...WINDS BECOME
EASTERLY AND CLOUD COVERAGE REMAINS BKN AT LEAST INITIALLY. CLOUD
COVERAGE DOES HELP TO KEEP TEMPS ON THE COOLER SIDE ON MONDAY.
DRIER AIR MOVES IN FOR THE FIRST HALF OF THE WEEK /BEHIND THE
BACKDOOR FRONT/. WITH THIS...DO NOT HAVE MOISTURE AROUND FOR MUCH
IN TERMS OF PRECIP AND THUS HAVE LIMITED POPS TO NO MENTION OR
SLIGHT CHANCE. DIFFERENCES EXIST BETWEEN THE GFS AND ECMWF IN THE
SECOND HALF THE OF THE EXTENDED. GFS BRINGS A COLD FRONT INTO THE
AREA ON FRIDAY...WHILE THE ECMWF KEEPS AN UPPER RIDGE ACROSS THE
SOUTHEAST. HAVE TENDED MORE TOWARDS THE GFS AND SHOWN AN INCREASE
IN CLOUDS/PRECIP FOR FRIDAY ASSOCIATED WITH THE FRONT.
DIFFERENCES ALSO EXIST STILL WITH HOW THE MODELS ARE HANDLING THE
POTENTIAL TROPICAL SYSTEM NEXT WEEK. GFS REMAINS FURTHER WEST AND
SLOWER WHILE THE ECMWF IS FURTHER EAST /ALTHOUGH LATEST RUN IS
WEST OF PREVIOUS RUN/ AND FASTER. NEITHER 00Z SOLUTION BRINGS
IMPACTS TO THE CWA...BUT REGARDLESS...STILL FAR OUT IN THE
FORECAST AND ITS SOMETHING THAT NEEDS TO BE WATCHED AS WE HEAD
INTO NEXT WEEK.
11
AVIATION...
12Z UPDATE...
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD DESPITE A
BIG CHANGE IN OVERALL WEATHER PATTERN. HIGH PRESSURE WEAKENS ITS
GRIP TODAY... ALLOWING SLIGHTLY BETTER CHANCE FOR SCT AFTERNOON
THUNDERSTORMS. THEN A BACKDOOR COLD FRONT SWEEPS ACROSS THE AREA
EARLY ON SUN... BRINGING MID LEVEL CIGS AND SCT TO NUMEROUS SHOWERS
WITH SOME EMBEDDED THUNDERSTORMS TO THE AREA EARLY ON SUN. WILL SHOW
TEMPO -TSRA 19-23Z TODAY... THEN PROB30 -SHRA 12-18Z SUN WITH THE
FRONT. CURRENT NW WINDS PERSIST TODAY AROUND 8-11KTS... THEN SHIFT
NE AROUND 08-10Z SUN WITH SPEEDS AROUND 10-12KTS ON SUN.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM ON ALL ELEMENTS.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 97 73 88 70 / 30 30 60 30
ATLANTA 93 75 90 72 / 30 20 60 40
BLAIRSVILLE 88 69 83 67 / 30 30 60 40
CARTERSVILLE 94 71 89 72 / 30 20 60 40
COLUMBUS 98 75 94 75 / 20 20 60 40
GAINESVILLE 94 73 87 71 / 30 30 60 40
MACON 99 73 93 72 / 20 20 60 40
ROME 95 71 91 73 / 30 20 60 40
PEACHTREE CITY 94 71 90 72 / 20 20 60 40
VIDALIA 99 75 94 74 / 20 20 60 40
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR THE FOLLOWING
ZONES: BALDWIN...BIBB...BLECKLEY...CLARKE...CRAWFORD...CRISP...
DODGE...DOOLY...EMANUEL...GLASCOCK...GREENE...HANCOCK...
HOUSTON...JASPER...JEFFERSON...JOHNSON...JONES...LAURENS...
MACON...MONROE...MONTGOMERY...MORGAN...OCONEE...OGLETHORPE...
PEACH...PULASKI...PUTNAM...SCHLEY...STEWART...SUMTER...
TALIAFERRO...TAYLOR...TELFAIR...TOOMBS...TREUTLEN...TWIGGS...
WARREN...WASHINGTON...WEBSTER...WHEELER...WILCOX...WILKES...
WILKINSON.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
155 AM EDT SAT AUG 23 2014
.SYNOPSIS...
A BACK DOOR COLD FRONT WILL MOVE INTO AND THROUGH THE NORTHERN AND
CENTRAL MIDLANDS SATURDAY...AND THEN SHIFT TOWARDS THE CSRA
SUNDAY. THIS WILL LEAD TO A CHANCE OF THUNDERSTORMS ALONG AND
AHEAD OF THE FRONT...WITH TEMPERATURES RETURNING TO MORE NORMAL
LEVELS BEHIND IT. THE FRONT WILL LINGER SOUTH OF THE CSRA EARLY TO
MID NEXT WEEK...LEADING TO GENERALLY FAIR WEATHER WITH NEAR NORMAL
TEMPERATURES.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
WV LOOP SHOWS WEAK S/W MOVING SOUTHEASTWARD TOWARD THE NRN CWA/PEE
DEE REGION. MODELS ALSO SHOW THIS S/W MOVING SOUTH/SOUTHEAST
OVERNIGHT. 88D REGIONAL COMPOSITE SHOWS A CLUSTER OF SHRA/TSRA
JUST NORTH OF CLT. HRRR INDICATES THAT SOME OF THIS ACTIVITY COULD
SLIP INTO THE NRN MIDLANDS/PEE DEE OVER THE NEXT FEW HOURS. HAVE
INCREASED POPS SLIGHTLY ACROSS LANCASTER...CHESTERFIELD...NRN
KERSHAW AND NERN LEE COUNTY. OVERNIGHT LOWS IN THE LOW/MID 70S
LOOK ON TRACK.
OTHERWISE...SURFACE LOW PRESSURE ALONG THE VA COAST IS FORECAST TO
MOVE SOUTHWARD OVERNIGHT INTO EASTERN NC. THIS WILL ALLOW A
BACKDOOR COLD FRONT TO APPROACH THE NORTHERN MIDLANDS/PEE DEE
AROUND DAYBREAK SATURDAY. KEPT OVERNIGHT LOWS NEAR CONSENSUS IN
THE LOWER AND MIDDLE 70S.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM SUNDAY/...
MAIN ISSUE FOR SATURDAY AND INTO SUNDAY IS TIMING OF APPROACHING
BACK DOOR FRONT. THINK PRE-FRONTAL TROUGH SETS UP ACROSS SOUTHERN
CWA SATURDAY WITH FRONT IN EASTERN NORTH CAROLINA SHIFTING
SOUTHWEST DURING SATURDAY EVENING. MOS POP GUIDANCE LOW BUT SREF
AND MODEL QPF SUGGEST SCATTERED SHOWERS AND THUNDERSTORMS AHEAD
AND ALONG FRONT AS AIR MASS MODERATELY UNSTABLE AND MOISTURE
INCREASING...PRECIPITABLE WATER MAY RISE TO AROUND 2 INCHES.
WARM MAX TEMPS STILL POSSIBLE SAT AHEAD OF THE FRONT...WITH
WARMEST TEMPS FAVORING THE CSRA WHERE TEMPS COULD REACH 100 AGAIN.
WITH NAM BEING SLIGHTLY FASTER THAN GFS WITH THE BACK DOOR FRONT...THE
NAM MOS IS SLIGHTLY COOLER THAN THE GFS MOS FOR SAT MAX
TEMP...ESPECIALLY NORTH AND CENTRAL. EVEN IF TEMPS NEAR 100
REACHED AGAIN SAT...GUIDANCE STILL SUGGESTS DEWPOINTS LOW ENOUGH
TO PRECLUDE HEAT INDEX VALUES FROM REACHING OUR HEAT ADVISORY
CRITERIA OF 110F.
FRONT EXPECTED TO SHIFT SW THRU THE FA SAT NIGHT THRU SUN NIGHT.
EXPECT CHANCE POPS NEAR AND JUST AHEAD OF THE FRONT...WITH COOLING
TEMPS ALONG AND NORTH OF IT. SO...POPS SUN AFTERNOON FAVORING THE
CSRA WHERE INSTABILITY/LOW LEVEL CONVERGENCE STRONGER. HIGH TEMPS SUNDAY
SHOULD BE NOTICEABLY LESS BEHIND THE FRONT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
MODELS IN GOOD AGREEMENT WITH MOVING THE FRONT SOUTH OF THE SAVANNAH
RIVER WITH UPPER LEVEL RIDGE BUILDING IN FOR THE WEEK. WITH COOLER
DRY AIR SETTLING IN WILL BRING SLIGHTLY BELOW NORMAL TEMPS. EXPECT
MAX TEMPS 85 TO 90 EARLY TO MID WEEK RISING BACK INTO THE LOWER 90S
LATER IN THE WEEK. OVERNIGHT MINS WILL BE 65 TO 70 RISING INTO
THE LOWER 70S LATER IN THE WEEK.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
SCATTERED CONVECTIVE DEBRIS FROM THUNDERSTORMS ALONG THE NC/SC
LINE CONTINUE MOVING INTO THE TAF SITES. WITH THE WEAK FRONTAL
BOUNDARY SLOWLY MOVING SOUTHWARD EXPECT INCREASING MID AND UPPER
LEVEL CLOUDS OVERNIGHT...WHICH WILL WORK TO PREVENT FOG
DEVELOPMENT. THE FRONT WILL REMAIN NORTH OF THE TAF SITES THROUGH
THE PERIOD...WITH ISOLATED TO SCATTERED CONVECTION POSSIBLE
DURING THE AFTERNOON AND EVENING HOURS. CONFIDENCE REMAINS LOW IN
REGARD TO COVERAGE SO HAVE NOT INCLUDED MENTION OF CONVECTION IN
TAFS ATTM. BEST CHANCE FOR CONVECTION WILL BE CAE/CUB AND
NORTHWARD. WINDS THROUGH THE PERIOD WILL BE NORTHERLY AT 7 KNOTS
OR LESS.
EXTENDED AVIATION OUTLOOK...MVFR OR IFR CONDITIONS POSSIBLE IN LATE
NIGHT AND EARLY MORNING FOG SUNDAY AND MONDAY. ISOLATED AFTERNOON
AND EVENING THUNDERSTORMS MAY ALSO BRING RESTRICTIONS SUNDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS POCATELLO ID
150 PM MDT SAT AUG 23 2014
.SHORT TERM...TONIGHT THROUGH TUESDAY. THE LATEST SATELLITE IMAGERY
WAS SHOWING A LOW PRESSURE SYSTEM OVERHEAD WITH SEVERAL WELL DEFINED
VORT FEATURES EMBEDDED IN THE FLOW. CURRENT RADAR TRENDS ARE SHOWING
A RAPID INCREASE IN SHOWER ACTIVITY EARLY THIS MORNING AND CURRENTLY
ANTICIPATE THIS CONTINUE AND BECOME MORE LINEARLY FOCUSED THROUGH
THE AFTERNOON AS ONE OF THE EMBEDDED VORT FEATURES PLUNGES SOUTH
THROUGH THE SNAKE RIVER PLAIN AND THE SURFACE WINDS BEGIN TO FORM A
CONVERGENCE AREA WITH THUNDERSTORMS ACROSS THE UPPER VALLEY THAT
DRIFTS SOUTH LATE THIS AFTERNOON BEFORE DISSIPATING LATER THIS
EVENING AS THE UPPER LOW BEGINS TO LIFT NE INTO SRN MONTANA.
ANTICIPATING A BRIEF BRAKE IN THE ACTION SUNDAY MORNING BEFORE THE
NEXT PAC THROUGH DIGS INTO THE NW STATES SUNDAY AFTERNOON FURTHER
WEST THAN PREVIOUS PROGS SPINNING UP A SHALLOW CLOSED LOW OVER THE
NRN GREAT BASIN SUNDAY AFTERNOON/NIGHT WITH AN INCREASE IN SHOWER
ACTIVITY WHICH LINGERS THROUGH MONDAY NIGHT/TUESDAY AS THE LOW
SLOWLY FILLS AND GRADUALLY SWINGS EAST ALONG THE NEVADA/UTAH BORDER
BEFORE EXITING EAST OF THE REGION TUESDAY EVENING.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT SATURDAY. DRIER AND WARMER
CONDITIONS DEVELOP ACROSS SRN IDAHO WEDNESDAY THROUGH FRIDAY AS A
TRANSIENT UPPER RIDGE MIGRATES EAST ACROSS THE AREA AHEAD OF THE
NEXT APPROACHING PAC STORM SYSTEM. THE 12Z GFS CONTINUES TO TAP INTO
THE REMNANTS OF HURRICANE MARIE AS IT LIFTS NE OUT OF THE
SUB-TROPICAL ERN PACIFIC WATERS OFF THE MEXICAN COAST TO A POSITION
WELL OFF THE CALIFORNIA COAST FRIDAY AHEAD OF THE INCOMING TROUGH.
AS THE TROUGH MOVES INLAND SATURDAY...THE GFS BEGINS TO INTERACT
WITH THE SUB-TROPICAL MOISTURE PRODUCING WIDESPREAD SHOWER ACTIVITY
ACROSS IDAHO. THE 12Z ECMWF TAKES MARIE ON A MORE NWRLY TRAJECTORY
PREVENTING THE INCOMING TROUGH FROM TAPPING INTO THE MOIST
SUB-TROPICAL SYSTEM WITH DRIER CONSEQUENCES. WE WILL CONTINUE TO
MONITOR THE MODEL TRENDS FOR ANY CHANGE IN EITHER MODEL. HUSTON
&&
.AVIATION...UPPER LOW IS SLOWLY DRIFTING ACROSS SOUTHEAST IDAHO THIS
AFTERNOON. ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE IN THE
COLD CORE REGION WITH MOST OF THE STRATIFORM PRECIP WRAPPING AROUND
THE LOW INTO THE SALMON/CHALLIS AREA. STARTING TO SEE CEILINGS AT
KIDA LIFT FROM IFR TO MVFR...AND SHOULD SCATTER OUT IN THE EARLY
AFTERNOON. HRRR SIGNALS INCREASING SHOWER ACTIVITY AROUND
MID-AFTERNOON AND INTO THE EVENING AS LOW MOVES INTO THE YELLOWSTONE
AREA. FORECAST SOUNDINGS FAVORING 6000 FT TO 10000 FT CEILINGS
OVERNIGHT INTO TOMORROW. HINSBERGER
&&
.FIRE WEATHER...A LITTLE LESS COVERAGE OF SHOWERS AND THUNDERSTORMS
TODAY AS UPPER LOW SLOWLY DRIFTS ACROSS SOUTHEAST IDAHO TODAY.
HEAVIER PRECIP IS BEING WRAPPED AROUND THE LOW INTO LEMHI COUNTY.
DRIER WEATHER IS EXPECTED SUNDAY AS INFLUENCE OF LOW WANES...BUT
MODELS ARE PROJECTING ANOTHER UPPER LOW TO DROP INTO OR/ID SUNDAY
NIGHT. IMPULSES OF ENERGY AROUND THE LOW WILL BRING MORE SHOWERS AND
THUNDERSTORMS TO THE AREA DURING THE DAY MONDAY...AND MAY LINGER
INTO TUESDAY MORNING. UPPER RIDGING WILL BRING DRIER WEATHER TO THE
REGION LATER ON TUESDAY AND SHOULD LAST THROUGH FRIDAY. A PACIFIC
TROUGH WILL APPROACH THE WEST ON FRIDAY. REMNANTS OF HURRICANE MARIE
MAY BE POSITIONED TO CONTRIBUTE ITS TROPICAL MOISTURE THOUGH THERE
IS STILL SOME UNCERTAINTY WITH ITS TRACK IN RELATION TO THE PACIFIC
TROUGH...BUT SIGNS POINT TO ANOTHER WET WEEKEND. HINSBERGER
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
329 PM CDT SAT AUG 23 2014
.DISCUSSION...
326 PM CDT
A PERSISTENT UPPER RIDGE THAT HAS BEEN SITTING OVER THE MIDWEST WILL
GRADUALLY FLATTEN AND BE PUSHED TO THE SOUTH AND EAST OVER THE NEXT
FEW DAYS...BUT NOT UNTIL THIS COMING THURSDAY OR FRIDAY WILL IT
AND ITS SURFACE MANIFESTATION BE PUSHED FAR ENOUGH AWAY TO ALLOW A
SURGE OF COOLER AND DRIER AIR INTO THE LOCAL AREA. UNTIL MIDWEEK
THE WARM AND HUMID AIRMASS WILL REMAIN IN PLACE...SUPPORTING
ONGOING CHANCES OF SHOWERS AND THUNDERSTORMS...WITH HEAT INDICIES
ON MONDAY APPROACHING THE LOCAL HEAT ADVISORY CRITERIA OF 105F.
POTENT SHORTWAVES LIFTING THROUGH THE TOP OF THE RIDGE TODAY HAVE
SUPPORTED A BROAD CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN. MODELS
ARE IN REASONABLE AGREEMENT IN SHOWING SIMILAR BUT SOMEWHAT WEAKER
WAVES LIFTING THROUGH AGAIN TOMORROW...THOUGH THE FOCUS IS A BIT
FARTHER WEST. ALSO...MORE PRONOUNCED WARM ADVECTION AROUND THE
850MB LEVEL LOCALLY IS EXPECTED TO INHIBIT CONVECTIVE DEVELOPMENT
COMPARED TO WHAT WE SAW TODAY...AND THE INCREASED CLOUDINESS FROM
THE SHORTWAVES SHOULD ALSO SERVE TO LIMIT THE DEGREE OF AFTERNOON
SURFACE HEATING.
AS A WEAK SURFACE TROUGH APPROACHES SLOWLY FROM THE NORTHWEST...TSRA
CHANCES CREEP BACK UP AGAIN MONDAY AND TUESDAY ALONG WITH...AND
BECAUSE OF...MORE PRONOUNCED LOW LEVEL HEATING WITH SOUTH TO
SOUTHWEST WINDS SUPPORTING BETTER MIXING AND A WEAKER CAP ALOFT.
MONDAY LOOKS TO BE WARMER THAN EITHER SUNDAY OR TUESDAY...AND
AMPLE MOISTURE WILL SUPPORT HEAT INDICIES BETWEEN 100 AND
105...NEAR THE CRITERIA FOR A HEAT ADVISORY. IT IS A BIT EARLY TO
HOIST A HEADLINE BUT THIS WILL CONTINUE TO BE MONITORED.
BY WEDNESDAY THE TROUGH JUST TO OUR NORTHWEST WILL HAVE EVOLVED TO A
WARM FRONT ASSOCIATED WITH A LOW OVER THE PLAINS. THIS LOW THEN
LIFTS ALONG THIS BOUNDARY AND SETTLES OVER THE LOCAL AREA ON
THURSDAY BEFORE CONTINUING OFF TO THE EAST ON FRIDAY. HIGH
TEMPERATURES BOTH WEDNESDAY AND THURSDAY COULD BE TRICKY DEPENDING
ON WHERE THE SURFACE BOUNDARIES SET UP...BUT INCREASED CLOUDINESS
AND ONGOING TSRA CHANCES SHOULD KEEP THOSE DAYS COOLER THAN MONDAY
AND TUESDAY. THE MORE SIGNIFICANT CHANGE OF AIRMASS WILL THEN BE
IN PLACE ACROSS THE ENTIRE AREA BY FRIDAY AND SATURDAY...THOUGH
THE ECMWF IS A BIT SLOWER THAN THE GFS IN PUSHING THIS BOUNDARY
THROUGH.
LENNING
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* RAIN WITH THE CHANCE FOR A WIDELY SCATTERED LIGHTNING STRIKE
THROUGH 21Z...THEN A SMALL CHANCE FOR ISOLATED SHRA/TSRA THROUGH
THIS EVE.
* EAST-NORTHEAST WINDS EASING IN SPEED THROUGH LATE AFTERNOON BUT
REMAINING EASTERLY IN DIRECTION.
* POTENTIAL FOR IFR CIGS AND/OR VISIBILITY TONIGHT INTO SUNDAY
MORNING.
* LAKE BREEZE TURNING WINDS EASTERLY AROUND OR POSSIBLY ABOVE 10
KT SUNDAY.
//DISCUSSION...UPDATED 20Z...
LINE OF STORMS HAS MOVED EAST-SOUTHEAST OF ORD AND MDW WITH
STRATIFORM RAIN TO CONTINUE THROUGH 21Z. CLOUD-TO-GROUND LIGHTNING
DENSITY IN THIS HAS BEEN VERY SPARSE SO HAVE OPTED NOT TO MENTION
TSRA BEYOND 20Z. EASTERLY WINDS HAVE OCCASIONALLY GUSTED ON THE
BACKSIDE OF THE STORMS AND SHOULD SEE A SLOW EASE IN SPEED. THE
RAINFALL ALONG WITH DIMINISHING WIND SPEED GOING TO THIS
EVE...LIKELY WILL LEAD TO BETTER POTENTIAL FOR FOG AND/OR STRATUS.
PREV DISCUSSION...UPDATED 18Z...
AREA OF SHOWERS AND STORMS CONTINUES TO MOVE EASTWARD WITH A SLOW
WANING TREND...ESPECIALLY IN PART OF THE SEGMENT JUST UPSTREAM OF
ORD AND MDW. WHILE THAT IS THE CASE...INCREASED CONVERGENCE
BETWEEN THE OUTFLOW AND THE LAKE BREEZE IN UNCAPPED AIR WILL
LIKELY SPARK MORE STORMS. THIS ALSO COULD EXTEND THE TSRA TIMING.
SO FEEL COMFORTABLE WITH THE TSRA STILL INDICATED IN THE
CHICAGOLAND TAFS. STRATIFORM RAIN BEHIND THIS WILL LIKELY BE
ACCOMPANIED WITH MVFR CONDITIONS. SCATTERED SHOWERS AND STORMS ARE
POSSIBLE BEHIND THIS DURING THE LATTER HALF OF THE AFTERNOON INTO
THE EVENING IN THE CONTINUED MOISTURE RICH AIR MASS.
THE WIND DIRECTION WILL LIKELY TURN SOUTHWEST AS THE STORMS
PASS...AS ALL OBSERVATIONS SITES HAVE INDICATED THAT UPSTREAM AND
RADAR SHOW WELL-DEFINED OUTFLOW. THE SPEED OF THE OUTFLOW HAS
SLOWED SOME...SO THE DEGREE OF GUSTS AT CHICAGOLAND TAF SITES IS
EXPECTED TO BE LESS THAN 30 KT. THE WIND DIRECTION BEHIND THE
INITIAL PUSH OF STORMS MAY BECOME VARIABLE...BUT IS ANTICIPATED TO
TURN EAST OR SOUTHEAST BASED ON THE SYNOPTIC FLOW AND CLIMATOLOGY
FOR POST-THUNDERSTORM WINDS AT ORD.
THE MOISTURE IN THE LOW-LEVELS AIDED BY RAIN EARLY THIS AFTERNOON
WILL SET THE STAGE ONCE AGAIN FOR FOG AND LOW CIGS
TONIGHT...HOWEVER THE COVERAGE OF THIS IS DIFFICULT TO DETERMINE
AT THIS TIME.
A LAKE BREEZE LOOKS LIKELY ON SUNDAY AFTERNOON INTO NORTHEAST
ILLINOIS THAT WILL PROBABLY REACH BOTH ORD AND MDW.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH IN RAIN END TIME. LOW IN WHETHER ANYMORE SHRA/TSRA WILL
OCCUR THROUGH THIS EVE.
* MEDIUM IN WIND DIRECTION AND SPEED THROUGH EARLY THIS EVE.
* MEDIUM IN SOME FORM OF IFR RESTRICTION LATE TONIGHT INTO EARLY
SUNDAY MORNING. LOW ON WHETHER FOG AND/OR CIG.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA WITH
OCCASIONAL MVFR.
FRIDAY...VFR WITH SLIGHT CHANCE TSRA.
MTF
&&
.MARINE...
153 PM CDT
RELATIVELY LIGHT WINDS ARE IN PLACE THIS AFTERNOON AS A WEAK
PRESSURE GRADIENT IS IN PLACE ACROSS THE REGION. WINDS WILL BEGIN TO
FRESHEN UP SLIGHTLY TONIGHT AND VEER TO THE SOUTHEAST AS BROAD AREA
OF LOW PRESSURE OVER THE PLAINS BEGINS TO CONSOLIDATE AND DEEPEN AS
IT LIFTS TOWARDS THE CANADIAN PRAIRIES. THIS LOW WILL DRAG A WEAK
COLD FRONT SOUTH ACROSS LAKE MICHIGAN LATE TUESDAY INTO WEDNESDAY
WITH WINDS TURNING TO THE NORTH BEHIND THROUGH THE REMAINDER OF THE
WEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
319 PM CDT Sat Aug 23 2014
.SHORT TERM...(This evening through Sunday)
ISSUED AT 319 PM CDT SAT AUG 23 2014
Southern flank of morning thunderstorm complex continues to impact
the northeast KILX CWA around Champaign and Danville this afternoon,
with only minimal development noted further southwest along the
trailing outflow boundary. Models have once again handled the
situation poorly, with the NAM/GFS being too aggressive with
convective development and the HRRR keeping system too far north.
Think storms will gradually push into Indiana over the next 3 to 4
hours, followed by only isolated convection across the eastern CWA
early this evening. Once daytime instability wanes, dry conditions
are expected overnight. With clearing skies and light winds, fog
will likely develop late tonight into Sunday morning. Forecast
soundings and numeric guidance both suggest at least some
restriction to visibilities, and based on what happened last night,
think its prudent to carry patchy fog late tonight. Upper ridge
axis will continue to control the weather across central Illinois on
Sunday, providing hot and mainly dry conditions. Some models are
hinting that widely scattered convection may fire along the Indiana
border by afternoon, but think this is a bit overdone. Will only
maintain slight chance PoPs across the far southeast, with dry
weather elsewhere. High temperatures will reach the lower 90s,
resulting in heat index values of 100 to 105 degrees.
&&
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 319 PM CDT SAT AUG 23 2014
Medium range models are generally in good agreement for the first
few days of next week, then they digress pretty rapidly for two
reasons. First is the difference in solutions involving the speed
and strength of the upper level trough expected to move from the
Rockies to Midwest. This looks like it is being caused by the second
main difference, which is a lot of uncertainty with the speed and
motion of a pending tropical system in the western Atlantic. These
tropical systems tend to back up the west-east progression of
weather systems in the middle U.S. Thus, there is a greater than
normal level of uncertainty with the forecast for Wednesday through
the end of the week.
In the nearer term period for Monday and Tuesday, it appears likely
that the hot and humid conditions will continue. Monday could end up
being one of the hottest days with highs from 93-95 in central IL
and 91-93 in east/southeast IL. This will keep heat index values in
the 105-108 range in much of central and southeast IL, so will keep
the heat advisory going through Monday. Considered extending the
advisory into Tuesday, but will hold off for now since there is some
level of uncertainty as to the amount of increasing cloudiness
during the day, which could keep temps down just a bit.
The movement of a cold front, associated with aforementioned
approaching upper level trough, will really depend on the east coast
tropical system. The most likely scenario, which is not really
handled very well by any model, is that the front will slowly
approach - and may even get hung up in central IL for a day or two.
Thus, will stick with a prolonged period of scattered showers/t-storms
Wednesday into Friday. The cloudiness associated with this rain
potential will keep temperatures down in the 80s, ending the stretch
of hot weather. However, longer term trends indicate the possibility
that we may see a return to very warm conditions for Labor Day
weekend.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1236 PM CDT SAT AUG 23 2014
Southern flank of storm complex tracking across northern Illinois
is skirting along the I-74 corridor early this afternoon. Storms
have already impacted KPIA with heavy rain and gusty winds up to
around 25kt and will push through KBMI over the next hour. Still
some question whether they will hold together and reach far enough
south to impact KCMI, so have only gone with VCTS there. Elsewhere
around the area, will maintain dry conditions through the
afternoon. Once convection exits into Indiana, skies will
gradually clear by this evening. Due to light winds and very high
dewpoints, think fog will once again develop across the area
overnight. Have therefore included restricted visbys down to
between 2 and 4 miles between 09z and 14z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY until 7 PM CDT Monday FOR ILZ042-047>054-056-
061>063-066>068-071>073.
HEAT ADVISORY from Noon Sunday to 7 PM CDT Monday FOR ILZ036-040-
041.
&&
$$
SHORT TERM...BARNES
LONG TERM...MILLER
AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
304 PM CDT SAT AUG 23 2014
.MESOSCALE DISCUSSION...
115 PM CDT
LINE OF STORMS IS MOVING EAST INTO THE CHICAGOLAND AREA EARLY THIS
AFTERNOON. WHILE THIS HAS SHOWN A GRADUAL WEAKENING
TREND WITH LESS LIGHTNING...DESTABILIZATION ACROSS NORTHWEST
IN...EASTERN IL...AND INTO THE SOUTH CHICAGO METRO THE PAST FEW
HOURS SHOULD AID IN THE ACTIVITY TO AT LEAST PERSIST WITH HEAVY
RAINFALL RATES. IN ADDITION...CONVERGENCE FROM THE SYSTEM OUTFLOW
AND THE LAKE BREEZE HAS ALREADY FIRED A FEW ADDITIONAL CELLS AND
THAT WILL LIKELY CONTINUE TO OCCUR IN SUBURBAN AREAS THROUGH 2-3
PM. THE AREA OF STORMS ALSO SHOULD FURTHER SLOW AS IT RUNS INTO
THE MARINE LAYER. THIS MAY CAUSE HEAVY RAINFALL RATES TO PERSIST
OVER THE SAME URBAN AREAS FOR A WHILE...INCLUDING THOSE THAT WERE
HIT HARD LATE THURSDAY NIGHT. WILL BE MONITORING CLOSELY. SEVERE
THREAT APPEARS MINIMAL...WITH MAINLY THE FAR SOUTHEAST CWA BEING
THE ONE AREA THAT COULD SEE AN ISOLATED FLARE UP TO THAT LEVEL.
NOW THAT AREAS HAVE BEEN RAIN COOLED...WILL ADJUST TEMPERATURES
CONSIDERABLY DOWNWARD THE REST OF THE AFTERNOON.
MTF
&&
.DISCUSSION...
959 AM CDT
THE FORECAST HAS BEEN UPDATED TO REFLECT GREATER CLOUD COVER
AREAWIDE AND HIGHER POPS ACROSS MAINLY NORTH CENTRAL ILLINOIS
DURING THE EARLY-MID AFTERNOON.
A BROAD MESOSCALE CONVECTIVE SYSTEM WITH A LINE OF STORMS ON ITS
FRONT EDGE IS CURRENTLY ADVANCING EAST OVER THE MISSISSIPPI
RIVER AND FAR WESTERN ILLINOIS. THIS CONTINUES TO HOLD TOGETHER
WELL WITH ONLY SUBTLE CLOUD TOP WARMING AND NO FADE IN LIGHTNING
ACTIVITY OVER THE PAST COUPLE HOURS. THIS COMPLEX HAS BEEN ONGOING
FOR OVER NINE HOURS SO NOT SURPRISED TO SEE THAT THE RADAR LOOP
INDICATES THE LIKELY PRESENCE OF A CONVECTIVELY-INDUCED VORTICITY
MAXIMUM /MCV/ IN FAR EASTERN IA. THIS WITH A COLD POOL IS HELPING
TO USHER PUSH THE STORMS MORE EASTWARD THAN THE NORTHEAST MOVEMENT
OF THE PARENT SHORTWAVE WOULD INDICATE. DESPITE WHAT SHOULD BE A
GRADUAL FACE INTO THE EARLY AFTERNOON WITH THE UPPER SUPPORT
MOVING NORTHEAST AND A DECAYING LOW-LEVEL JET PER PROFILERS...2.2
INCH PWAT AIR /99TH PERCENTILE/ AHEAD OF THE MCV WILL LIKELY
SUPPORT SHOWERS AND SOME STORMS INTO NORTH CENTRAL ILLINOIS
BETWEEN NOON AND 3 PM. STILL SEEING SOME EMBEDDED HOURLY PRECIP
REPORTS OF A HALF TO ONE INCH WITH THIS...AND SOME OF THIS
EFFICIENCY COULD CERTAINLY OCCUR ALONG AND WEST OF I-39 DURING THE
EARLY AFTERNOON.
UNDER THE INFLUENCE OF WEAK UPPER LEVEL FLOW...THE MCV IS
FORECAST BY THE RAP AND NAM TO CONTINUE TO SLOW AS IT MOVES INTO
NORTH CENTRAL IL. DESTABILIZATION AHEAD OF IT MAY SUPPORT
ISOLATED OR SCATTERED SHOWERS/STORMS LATER THIS AFTERNOON FURTHER
EAST TOWARD CHICAGO AND THE I-57 CORRIDOR INTO NORTHWEST
INDIANA...BUT CONFIDENCE ON THIS IS LOW AS ANVIL SHIELD WILL
INHIBIT THE RATE OF WARMTH...WITH MOST GUIDANCE INDICATING THE
PRESENCE OF A CAP AND LOW-LEVEL FLOW OFF THE LAKE IN FAR NORTHEAST
IL.
MINOR TWEAKS MADE TO HOURLY TEMPERATURES AND DEW POINTS.
MTF
//PREV DISCUSSION...
327 AM...FORECAST CONCERNS INCLUDE THUNDERSTORM CHANCES/TIMING
THROUGH THE PERIOD ALONG WITH HIGH TEMPERATURES/HEAT INDICES
THROUGH MONDAY.
AREAS OF FOG CONTINUE TO DEVELOP WITH VISIBILITIES DROPPING UNDER
1SM IN A FEW LOCATIONS. NOT EXPECTING WIDESPREAD DENSE FOG THIS
MORNING BUT WILL NEED TO MONITOR OBS OVER THE NEXT FEW HOURS. THE
FOG WILL LIFT THIS MORNING BUT WITH LITTLE CHANGE TO THE AIRMASS
FOG WILL BE POSSIBLE AGAIN TONIGHT INTO SUNDAY MORNING.
A FEW SHOWERS DEVELOPED ACROSS NORTHERN LAKE COUNTY IN NORTHEAST
IL LATE FRIDAY EVENING AND PERSISTED FOR A FEW HOURS BEFORE
DISSIPATING. OTHERWISE...CONVECTION HAS BEEN FOCUSED FURTHER WEST
EARLY THIS MORNING IN THE VICINITY OF THE LOW LEVEL JET. SOME OF
THIS ACTIVITY OVER EASTERN IA MAY ARRIVE ACROSS THE WESTERN CWA
LATER THIS MORNING...LIKELY IN A DECAYING FORM. BUT OTHER THAN AN
ISOLATED SHOWER...EXPECT THE NEXT SEVERAL HOURS TO BE MAINLY DRY.
CONFIDENCE REGARDING THUNDERSTORM CHANCES THIS AFTERNOON INTO
THIS EVENING IS LOW THOUGH THERE IS SOME CONSENSUS FOR DEVELOPMENT
BY EARLY AFTERNOON ACROSS WESTERN/NORTHWEST IL FROM REMNANTS OF
CONVECTION OVER EASTERN NEBRASKA/WESTERN IA. HOW FAR IT CONTINUES
EAST OR NORTHEAST BEFORE WEAKENING IS ANOTHER UNCERTAINTY. MADE NO
SIGNIFICANT CHANGES FOR TODAY MAINTAINING 30-40 POPS. TRENDS WILL
NEED TO BE MONITORED THRU THE MORNING. DEWPOINTS IN THE 70S AND
PRECIPITABLE WATER VALUES APPROACHING 2 INCHES WILL LEAD TO VERY
HEAVY RAIN WITH ANY THUNDERSTORMS THAT DO DEVELOP AND POSSIBLY
FLASH FLOODING...ESPECIALLY IF THE RAIN FALLS OVER HARDER HIT
AREAS FROM FRIDAY MORNING.
THE UPPER RIDGE THEN BUILDS ACROSS THE AREA TONIGHT AND SUNDAY AND
PRECIP CHANCES LOOK BELOW MENTIONABLE FROM LATE TONIGHT THROUGH
MONDAY MORNING. CAN/T COMPLETELY RULE OUT SOME ISOLATED ACTIVITY...
IN PARTICULAR ON A LAKE BREEZE SUNDAY AFTERNOON. A FRONTAL
BOUNDARY WILL MOVE ACROSS THE UPPER MIDWEST SUNDAY NIGHT INTO
MONDAY WITH SOME DIFFERENCES AS TO HOW FAR SOUTH THIS BOUNDARY
WILL SETTLE MONDAY AFTERNOON INTO MONDAY NIGHT. THIS WOULD LIKELY
BE THE NEXT CHANCE OF THUNDERSTORMS WITH THE GEM/ECMWF BOTH
PUSHING THE FRONT THROUGH MUCH OF THE CWA BY TUESDAY MORNING. THIS
BOUNDARY THEN MEANDERS NEAR THE IL/WI BORDER INTO THURSDAY WITH
THE POSSIBILITY OF A PROLONGED UNSETTLED PATTERN ACROSS THE AREA.
CLOUD COVER/CONVECTION TODAY WILL LIKELY KEEP TEMPS IN THE 80S...
THOUGH WITH THE URBAN AREAS STARTING FROM LOWER/MID 70S...ANY
LONGER PERIOD OF SUNSHINE TODAY COULD ALLOW A FEW PLACES TO TAG
90. TEMPS WILL WARM A FEW DEGREES SUNDAY BUT SOUTHEASTERLY WINDS
WILL KEEP THE LAKESHORE COOLER. MONDAY LOOKS TO BE THE BEST
CHANCE FOR TEMPS INTO THE LOWER 90S CWA WIDE BUT WILL BE DEPENDENT
ON CLOUD COVER AND TIMING/ARRIVAL OF ANY PRECIP. DEWPOINTS MAY
LOWER A FEW DEGREES...BACK INTO THE MID/UPPER 60S ACROSS PARTS OF
THE AREA SUNDAY. HEAT INDICES COULD RANGE FROM LOWER/MID 90S TO
100-105 FAR SOUTHWEST. DEWPOINTS THEN BACK INTO THE 70S EVERYWHERE
MONDAY WITH HEAT INDICES CLOSER TO 100-105 MOST AREAS WITH STILL
THE POTENTIAL TO REACH HEAT ADVISORY CRITERIA ACROSS THE FAR
SOUTHERN CWA MONDAY AFTERNOON. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* RAIN WITH THE CHANCE FOR A WIDELY SCATTERED LIGHTNING STRIKE
THROUGH 21Z...THEN A SMALL CHANCE FOR ISOLATED SHRA/TSRA THROUGH
THIS EVE.
* EAST-NORTHEAST WINDS EASING IN SPEED THROUGH LATE AFTERNOON BUT
REMAINING EASTERLY IN DIRECTION.
* POTENTIAL FOR IFR CIGS AND/OR VISIBILITY TONIGHT INTO SUNDAY
MORNING.
* LAKE BREEZE TURNING WINDS EASTERLY AROUND OR POSSIBLY ABOVE 10
KT SUNDAY.
//DISCUSSION...UPDATED 20Z...
LINE OF STORMS HAS MOVED EAST-SOUTHEAST OF ORD AND MDW WITH
STRATIFORM RAIN TO CONTINUE THROUGH 21Z. CLOUD-TO-GROUND LIGHTNING
DENSITY IN THIS HAS BEEN VERY SPARSE SO HAVE OPTED NOT TO MENTION
TSRA BEYOND 20Z. EASTERLY WINDS HAVE OCCASIONALLY GUSTED ON THE
BACKSIDE OF THE STORMS AND SHOULD SEE A SLOW EASE IN SPEED. THE
RAINFALL ALONG WITH DIMINISHING WIND SPEED GOING TO THIS
EVE...LIKELY WILL LEAD TO BETTER POTENTIAL FOR FOG AND/OR STRATUS.
PREV DISCUSSION...UPDATED 18Z...
AREA OF SHOWERS AND STORMS CONTINUES TO MOVE EASTWARD WITH A SLOW
WANING TREND...ESPECIALLY IN PART OF THE SEGMENT JUST UPSTREAM OF
ORD AND MDW. WHILE THAT IS THE CASE...INCREASED CONVERGENCE
BETWEEN THE OUTFLOW AND THE LAKE BREEZE IN UNCAPPED AIR WILL
LIKELY SPARK MORE STORMS. THIS ALSO COULD EXTEND THE TSRA TIMING.
SO FEEL COMFORTABLE WITH THE TSRA STILL INDICATED IN THE
CHICAGOLAND TAFS. STRATIFORM RAIN BEHIND THIS WILL LIKELY BE
ACCOMPANIED WITH MVFR CONDITIONS. SCATTERED SHOWERS AND STORMS ARE
POSSIBLE BEHIND THIS DURING THE LATTER HALF OF THE AFTERNOON INTO
THE EVENING IN THE CONTINUED MOISTURE RICH AIR MASS.
THE WIND DIRECTION WILL LIKELY TURN SOUTHWEST AS THE STORMS
PASS...AS ALL OBSERVATIONS SITES HAVE INDICATED THAT UPSTREAM AND
RADAR SHOW WELL-DEFINED OUTFLOW. THE SPEED OF THE OUTFLOW HAS
SLOWED SOME...SO THE DEGREE OF GUSTS AT CHICAGOLAND TAF SITES IS
EXPECTED TO BE LESS THAN 30 KT. THE WIND DIRECTION BEHIND THE
INITIAL PUSH OF STORMS MAY BECOME VARIABLE...BUT IS ANTICIPATED TO
TURN EAST OR SOUTHEAST BASED ON THE SYNOPTIC FLOW AND CLIMATOLOGY
FOR POST-THUNDERSTORM WINDS AT ORD.
THE MOISTURE IN THE LOW-LEVELS AIDED BY RAIN EARLY THIS AFTERNOON
WILL SET THE STAGE ONCE AGAIN FOR FOG AND LOW CIGS
TONIGHT...HOWEVER THE COVERAGE OF THIS IS DIFFICULT TO DETERMINE
AT THIS TIME.
A LAKE BREEZE LOOKS LIKELY ON SUNDAY AFTERNOON INTO NORTHEAST
ILLINOIS THAT WILL PROBABLY REACH BOTH ORD AND MDW.
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH IN RAIN END TIME. LOW IN WHETHER ANYMORE SHRA/TSRA WILL
OCCUR THROUGH THIS EVE.
* MEDIUM IN WIND DIRECTION AND SPEED THROUGH EARLY THIS EVE.
* MEDIUM IN SOME FORM OF IFR RESTRICTION LATE TONIGHT INTO EARLY
SUNDAY MORNING. LOW ON WHETHER FOG AND/OR CIG.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA WITH
OCCASIONAL MVFR.
FRIDAY...VFR WITH SLIGHT CHANCE TSRA.
MTF
&&
.MARINE...
153 PM CDT
RELATIVELY LIGHT WINDS ARE IN PLACE THIS AFTERNOON AS A WEAK
PRESSURE GRADIENT IS IN PLACE ACROSS THE REGION. WINDS WILL BEGIN TO
FRESHEN UP SLIGHTLY TONIGHT AND VEER TO THE SOUTHEAST AS BROAD AREA
OF LOW PRESSURE OVER THE PLAINS BEGINS TO CONSOLIDATE AND DEEPEN AS
IT LIFTS TOWARDS THE CANADIAN PRAIRIES. THIS LOW WILL DRAG A WEAK
COLD FRONT SOUTH ACROSS LAKE MICHIGAN LATE TUESDAY INTO WEDNESDAY
WITH WINDS TURNING TO THE NORTH BEHIND THROUGH THE REMAINDER OF THE
WEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
154 PM CDT SAT AUG 23 2014
.MESOSCALE DISCUSSION...
115 PM CDT
LINE OF STORMS IS MOVING EAST INTO THE CHICAGOLAND AREA EARLY THIS
AFTERNOON. WHILE THIS HAS SHOWN A GRADUAL WEAKENING
TREND WITH LESS LIGHTNING...DESTABILIZATION ACROSS NORTHWEST
IN...EASTERN IL...AND INTO THE SOUTH CHICAGO METRO THE PAST FEW
HOURS SHOULD AID IN THE ACTIVITY TO AT LEAST PERSIST WITH HEAVY
RAINFALL RATES. IN ADDITION...CONVERGENCE FROM THE SYSTEM OUTFLOW
AND THE LAKE BREEZE HAS ALREADY FIRED A FEW ADDITIONAL CELLS AND
THAT WILL LIKELY CONTINUE TO OCCUR IN SUBURBAN AREAS THROUGH 2-3
PM. THE AREA OF STORMS ALSO SHOULD FURTHER SLOW AS IT RUNS INTO
THE MARINE LAYER. THIS MAY CAUSE HEAVY RAINFALL RATES TO PERSIST
OVER THE SAME URBAN AREAS FOR A WHILE...INCLUDING THOSE THAT WERE
HIT HARD LATE THURSDAY NIGHT. WILL BE MONITORING CLOSELY. SEVERE
THREAT APPEARS MINIMAL...WITH MAINLY THE FAR SOUTHEAST CWA BEING
THE ONE AREA THAT COULD SEE AN ISOLATED FLARE UP TO THAT LEVEL.
NOW THAT AREAS HAVE BEEN RAIN COOLED...WILL ADJUST TEMPERATURES
CONSIDERABLY DOWNWARD THE REST OF THE AFTERNOON.
MTF
&&
.DISCUSSION...
959 AM CDT
THE FORECAST HAS BEEN UPDATED TO REFLECT GREATER CLOUD COVER
AREAWIDE AND HIGHER POPS ACROSS MAINLY NORTH CENTRAL ILLINOIS
DURING THE EARLY-MID AFTERNOON.
A BROAD MESOSCALE CONVECTIVE SYSTEM WITH A LINE OF STORMS ON ITS
FRONT EDGE IS CURRENTLY ADVANCING EAST OVER THE MISSISSIPPI
RIVER AND FAR WESTERN ILLINOIS. THIS CONTINUES TO HOLD TOGETHER
WELL WITH ONLY SUBTLE CLOUD TOP WARMING AND NO FADE IN LIGHTNING
ACTIVITY OVER THE PAST COUPLE HOURS. THIS COMPLEX HAS BEEN ONGOING
FOR OVER NINE HOURS SO NOT SURPRISED TO SEE THAT THE RADAR LOOP
INDICATES THE LIKELY PRESENCE OF A CONVECTIVELY-INDUCED VORTICITY
MAXIMUM /MCV/ IN FAR EASTERN IA. THIS WITH A COLD POOL IS HELPING
TO USHER PUSH THE STORMS MORE EASTWARD THAN THE NORTHEAST MOVEMENT
OF THE PARENT SHORTWAVE WOULD INDICATE. DESPITE WHAT SHOULD BE A
GRADUAL FACE INTO THE EARLY AFTERNOON WITH THE UPPER SUPPORT
MOVING NORTHEAST AND A DECAYING LOW-LEVEL JET PER PROFILERS...2.2
INCH PWAT AIR /99TH PERCENTILE/ AHEAD OF THE MCV WILL LIKELY
SUPPORT SHOWERS AND SOME STORMS INTO NORTH CENTRAL ILLINOIS
BETWEEN NOON AND 3 PM. STILL SEEING SOME EMBEDDED HOURLY PRECIP
REPORTS OF A HALF TO ONE INCH WITH THIS...AND SOME OF THIS
EFFICIENCY COULD CERTAINLY OCCUR ALONG AND WEST OF I-39 DURING THE
EARLY AFTERNOON.
UNDER THE INFLUENCE OF WEAK UPPER LEVEL FLOW...THE MCV IS
FORECAST BY THE RAP AND NAM TO CONTINUE TO SLOW AS IT MOVES INTO
NORTH CENTRAL IL. DESTABILIZATION AHEAD OF IT MAY SUPPORT
ISOLATED OR SCATTERED SHOWERS/STORMS LATER THIS AFTERNOON FURTHER
EAST TOWARD CHICAGO AND THE I-57 CORRIDOR INTO NORTHWEST
INDIANA...BUT CONFIDENCE ON THIS IS LOW AS ANVIL SHIELD WILL
INHIBIT THE RATE OF WARMTH...WITH MOST GUIDANCE INDICATING THE
PRESENCE OF A CAP AND LOW-LEVEL FLOW OFF THE LAKE IN FAR NORTHEAST
IL.
MINOR TWEAKS MADE TO HOURLY TEMPERATURES AND DEW POINTS.
MTF
//PREV DISCUSSION...
327 AM...FORECAST CONCERNS INCLUDE THUNDERSTORM CHANCES/TIMING
THROUGH THE PERIOD ALONG WITH HIGH TEMPERATURES/HEAT INDICES
THROUGH MONDAY.
AREAS OF FOG CONTINUE TO DEVELOP WITH VISIBILITIES DROPPING UNDER
1SM IN A FEW LOCATIONS. NOT EXPECTING WIDESPREAD DENSE FOG THIS
MORNING BUT WILL NEED TO MONITOR OBS OVER THE NEXT FEW HOURS. THE
FOG WILL LIFT THIS MORNING BUT WITH LITTLE CHANGE TO THE AIRMASS
FOG WILL BE POSSIBLE AGAIN TONIGHT INTO SUNDAY MORNING.
A FEW SHOWERS DEVELOPED ACROSS NORTHERN LAKE COUNTY IN NORTHEAST
IL LATE FRIDAY EVENING AND PERSISTED FOR A FEW HOURS BEFORE
DISSIPATING. OTHERWISE...CONVECTION HAS BEEN FOCUSED FURTHER WEST
EARLY THIS MORNING IN THE VICINITY OF THE LOW LEVEL JET. SOME OF
THIS ACTIVITY OVER EASTERN IA MAY ARRIVE ACROSS THE WESTERN CWA
LATER THIS MORNING...LIKELY IN A DECAYING FORM. BUT OTHER THAN AN
ISOLATED SHOWER...EXPECT THE NEXT SEVERAL HOURS TO BE MAINLY DRY.
CONFIDENCE REGARDING THUNDERSTORM CHANCES THIS AFTERNOON INTO
THIS EVENING IS LOW THOUGH THERE IS SOME CONSENSUS FOR DEVELOPMENT
BY EARLY AFTERNOON ACROSS WESTERN/NORTHWEST IL FROM REMNANTS OF
CONVECTION OVER EASTERN NEBRASKA/WESTERN IA. HOW FAR IT CONTINUES
EAST OR NORTHEAST BEFORE WEAKENING IS ANOTHER UNCERTAINTY. MADE NO
SIGNIFICANT CHANGES FOR TODAY MAINTAINING 30-40 POPS. TRENDS WILL
NEED TO BE MONITORED THRU THE MORNING. DEWPOINTS IN THE 70S AND
PRECIPITABLE WATER VALUES APPROACHING 2 INCHES WILL LEAD TO VERY
HEAVY RAIN WITH ANY THUNDERSTORMS THAT DO DEVELOP AND POSSIBLY
FLASH FLOODING...ESPECIALLY IF THE RAIN FALLS OVER HARDER HIT
AREAS FROM FRIDAY MORNING.
THE UPPER RIDGE THEN BUILDS ACROSS THE AREA TONIGHT AND SUNDAY AND
PRECIP CHANCES LOOK BELOW MENTIONABLE FROM LATE TONIGHT THROUGH
MONDAY MORNING. CAN/T COMPLETELY RULE OUT SOME ISOLATED ACTIVITY...
IN PARTICULAR ON A LAKE BREEZE SUNDAY AFTERNOON. A FRONTAL
BOUNDARY WILL MOVE ACROSS THE UPPER MIDWEST SUNDAY NIGHT INTO
MONDAY WITH SOME DIFFERENCES AS TO HOW FAR SOUTH THIS BOUNDARY
WILL SETTLE MONDAY AFTERNOON INTO MONDAY NIGHT. THIS WOULD LIKELY
BE THE NEXT CHANCE OF THUNDERSTORMS WITH THE GEM/ECMWF BOTH
PUSHING THE FRONT THROUGH MUCH OF THE CWA BY TUESDAY MORNING. THIS
BOUNDARY THEN MEANDERS NEAR THE IL/WI BORDER INTO THURSDAY WITH
THE POSSIBILITY OF A PROLONGED UNSETTLED PATTERN ACROSS THE AREA.
CLOUD COVER/CONVECTION TODAY WILL LIKELY KEEP TEMPS IN THE 80S...
THOUGH WITH THE URBAN AREAS STARTING FROM LOWER/MID 70S...ANY
LONGER PERIOD OF SUNSHINE TODAY COULD ALLOW A FEW PLACES TO TAG
90. TEMPS WILL WARM A FEW DEGREES SUNDAY BUT SOUTHEASTERLY WINDS
WILL KEEP THE LAKESHORE COOLER. MONDAY LOOKS TO BE THE BEST
CHANCE FOR TEMPS INTO THE LOWER 90S CWA WIDE BUT WILL BE DEPENDENT
ON CLOUD COVER AND TIMING/ARRIVAL OF ANY PRECIP. DEWPOINTS MAY
LOWER A FEW DEGREES...BACK INTO THE MID/UPPER 60S ACROSS PARTS OF
THE AREA SUNDAY. HEAT INDICES COULD RANGE FROM LOWER/MID 90S TO
100-105 FAR SOUTHWEST. DEWPOINTS THEN BACK INTO THE 70S EVERYWHERE
MONDAY WITH HEAT INDICES CLOSER TO 100-105 MOST AREAS WITH STILL
THE POTENTIAL TO REACH HEAT ADVISORY CRITERIA ACROSS THE FAR
SOUTHERN CWA MONDAY AFTERNOON. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* RAIN WITH A PERIOD OF THUNDER AND POSSIBLE IFR VISIBILITY
BETWEEN 19Z-21Z...WITH THE POTENTIAL FOR LINGERING SCATTERED
SHRA/TSRA INTO THE EVE.
* EAST-NORTHEAST WINDS SHIFTING SOUTHWEST WITH SHOWERS AND STORMS
THEN LIKELY BECOMING SOUTHEAST OR EAST AFTERWARD /NEAR 20Z/ AND
POTENTIALLY BEING AROUND 10 KT.
* POTENTIAL FOR IFR CIGS AND/OR VISIBILITY TONIGHT INTO SUNDAY
MORNING.
* LAKE BREEZE TURNING WINDS EASTERLY AROUND OR POSSIBLY ABOVE 10
KT SUNDAY.
//DISCUSSION...UPDATED 18Z...
AREA OF SHOWERS AND STORMS CONTINUES TO MOVE EASTWARD WITH A SLOW
WANING TREND...ESPECIALLY IN PART OF THE SEGMENT JUST UPSTREAM OF
ORD AND MDW. WHILE THAT IS THE CASE...INCREASED CONVERGENCE
BETWEEN THE OUTFLOW AND THE LAKE BREEZE IN UNCAPPED AIR WILL
LIKELY SPARK MORE STORMS. THIS ALSO COULD EXTEND THE TSRA TIMING.
SO FEEL COMFORTABLE WITH THE TSRA STILL INDICATED IN THE
CHICAGOLAND TAFS. STRATIFORM RAIN BEHIND THIS WILL LIKELY BE
ACCOMPANIED WITH MVFR CONDITIONS. SCATTERED SHOWERS AND STORMS ARE
POSSIBLE BEHIND THIS DURING THE LATTER HALF OF THE AFTERNOON INTO
THE EVENING IN THE CONTINUED MOISTURE RICH AIR MASS.
THE WIND DIRECTION WILL LIKELY TURN SOUTHWEST AS THE STORMS
PASS...AS ALL OBSERVATIONS SITES HAVE INDICATED THAT UPSTREAM AND
RADAR SHOW WELL-DEFINED OUTFLOW. THE SPEED OF THE OUTFLOW HAS
SLOWED SOME...SO THE DEGREE OF GUSTS AT CHICAGOLAND TAF SITES IS
EXPECTED TO BE LESS THAN 30 KT. THE WIND DIRECTION BEHIND THE
INITIAL PUSH OF STORMS MAY BECOME VARIABLE...BUT IS ANTICIPATED TO
TURN EAST OR SOUTHEAST BASED ON THE SYNOPTIC FLOW AND CLIMATOLOGY
FOR POST-THUNDERSTORM WINDS AT ORD.
THE MOISTURE IN THE LOW-LEVELS AIDED BY RAIN EARLY THIS AFTERNOON
WILL SET THE STAGE ONCE AGAIN FOR FOG AND LOW CIGS
TONIGHT...HOWEVER THE COVERAGE OF THIS IS DIFFICULT TO DETERMINE
AT THIS TIME.
A LAKE BREEZE LOOKS LIKELY ON SUNDAY AFTERNOON INTO NORTHEAST
ILLINOIS THAT WILL PROBABLY REACH BOTH ORD AND MDW.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH IN THUNDER OCCURRING. MEDIUM IN DURATION. LOW IN SHRA/TSRA
CHANCES THIS EVE.
* LOW IN WIND DIRECTION BETWEEN 19Z AND 21Z...MEDIUM IN WIND
CONDITIONS OTHERWISE...INCLUDING LAKE BREEZE TIMING ON SUNDAY.
* MEDIUM IN SOME FORM OF IFR RESTRICTION LATE TONIGHT INTO EARLY
SUNDAY MORNING. LOW ON WHETHER FOG AND/OR CIG.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA WITH
OCCASIONAL MVFR.
FRIDAY...VFR WITH SLIGHT CHANCE TSRA.
MTF
&&
.MARINE...
153 PM CDT
RELATIVELY LIGHT WINDS ARE IN PLACE THIS AFTERNOON AS A WEAK
PRESSURE GRADIENT IS IN PLACE ACROSS THE REGION. WINDS WILL BEGIN TO
FRESHEN UP SLIGHTLY TONIGHT AND VEER TO THE SOUTHEAST AS BROAD AREA
OF LOW PRESSURE OVER THE PLAINS BEGINS TO CONSOLIDATE AND DEEPEN AS
IT LIFTS TOWARDS THE CANADIAN PRAIRIES. THIS LOW WILL DRAG A WEAK
COLD FRONT SOUTH ACROSS LAKE MICHIGAN LATE TUESDAY INTO WEDNESDAY
WITH WINDS TURNING TO THE NORTH BEHIND THROUGH THE REMAINDER OF THE
WEEK.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
117 PM CDT SAT AUG 23 2014
.MESOSCALE DISCUSSION...
115 PM CDT
LINE OF STORMS IS MOVING EAST INTO THE CHICAGOLAND AREA EARLY THIS
AFTERNOON. WHILE THIS HAS SHOWN A GRADUAL WEAKENING
TREND WITH LESS LIGHTNING...DESTABILIZATION ACROSS NORTHWEST
IN...EASTERN IL...AND INTO THE SOUTH CHICAGO METRO THE PAST FEW
HOURS SHOULD AID IN THE ACTIVITY TO AT LEAST PERSIST WITH HEAVY
RAINFALL RATES. IN ADDITION...CONVERGENCE FROM THE SYSTEM OUTFLOW
AND THE LAKE BREEZE HAS ALREADY FIRED A FEW ADDITIONAL CELLS AND
THAT WILL LIKELY CONTINUE TO OCCUR IN SUBURBAN AREAS THROUGH 2-3
PM. THE AREA OF STORMS ALSO SHOULD FURTHER SLOW AS IT RUNS INTO
THE MARINE LAYER. THIS MAY CAUSE HEAVY RAINFALL RATES TO PERSIST
OVER THE SAME URBAN AREAS FOR A WHILE...INCLUDING THOSE THAT WERE
HIT HARD LATE THURSDAY NIGHT. WILL BE MONITORING CLOSELY. SEVERE
THREAT APPEARS MINIMAL...WITH MAINLY THE FAR SOUTHEAST CWA BEING
THE ONE AREA THAT COULD SEE AN ISOLATED FLARE UP TO THAT LEVEL.
NOW THAT AREAS HAVE BEEN RAIN COOLED...WILL ADJUST TEMPERATURES
CONSIDERABLY DOWNWARD THE REST OF THE AFTERNOON.
MTF
&&
.DISCUSSION...
959 AM CDT
THE FORECAST HAS BEEN UPDATED TO REFLECT GREATER CLOUD COVER
AREAWIDE AND HIGHER POPS ACROSS MAINLY NORTH CENTRAL ILLINOIS
DURING THE EARLY-MID AFTERNOON.
A BROAD MESOSCALE CONVECTIVE SYSTEM WITH A LINE OF STORMS ON ITS
FRONT EDGE IS CURRENTLY ADVANCING EAST OVER THE MISSISSIPPI
RIVER AND FAR WESTERN ILLINOIS. THIS CONTINUES TO HOLD TOGETHER
WELL WITH ONLY SUBTLE CLOUD TOP WARMING AND NO FADE IN LIGHTNING
ACTIVITY OVER THE PAST COUPLE HOURS. THIS COMPLEX HAS BEEN ONGOING
FOR OVER NINE HOURS SO NOT SURPRISED TO SEE THAT THE RADAR LOOP
INDICATES THE LIKELY PRESENCE OF A CONVECTIVELY-INDUCED VORTICITY
MAXIMUM /MCV/ IN FAR EASTERN IA. THIS WITH A COLD POOL IS HELPING
TO USHER PUSH THE STORMS MORE EASTWARD THAN THE NORTHEAST MOVEMENT
OF THE PARENT SHORTWAVE WOULD INDICATE. DESPITE WHAT SHOULD BE A
GRADUAL FACE INTO THE EARLY AFTERNOON WITH THE UPPER SUPPORT
MOVING NORTHEAST AND A DECAYING LOW-LEVEL JET PER PROFILERS...2.2
INCH PWAT AIR /99TH PERCENTILE/ AHEAD OF THE MCV WILL LIKELY
SUPPORT SHOWERS AND SOME STORMS INTO NORTH CENTRAL ILLINOIS
BETWEEN NOON AND 3 PM. STILL SEEING SOME EMBEDDED HOURLY PRECIP
REPORTS OF A HALF TO ONE INCH WITH THIS...AND SOME OF THIS
EFFICIENCY COULD CERTAINLY OCCUR ALONG AND WEST OF I-39 DURING THE
EARLY AFTERNOON.
UNDER THE INFLUENCE OF WEAK UPPER LEVEL FLOW...THE MCV IS
FORECAST BY THE RAP AND NAM TO CONTINUE TO SLOW AS IT MOVES INTO
NORTH CENTRAL IL. DESTABILIZATION AHEAD OF IT MAY SUPPORT
ISOLATED OR SCATTERED SHOWERS/STORMS LATER THIS AFTERNOON FURTHER
EAST TOWARD CHICAGO AND THE I-57 CORRIDOR INTO NORTHWEST
INDIANA...BUT CONFIDENCE ON THIS IS LOW AS ANVIL SHIELD WILL
INHIBIT THE RATE OF WARMTH...WITH MOST GUIDANCE INDICATING THE
PRESENCE OF A CAP AND LOW-LEVEL FLOW OFF THE LAKE IN FAR NORTHEAST
IL.
MINOR TWEAKS MADE TO HOURLY TEMPERATURES AND DEW POINTS.
MTF
//PREV DISCUSSION...
327 AM...FORECAST CONCERNS INCLUDE THUNDERSTORM CHANCES/TIMING
THROUGH THE PERIOD ALONG WITH HIGH TEMPERATURES/HEAT INDICES
THROUGH MONDAY.
AREAS OF FOG CONTINUE TO DEVELOP WITH VISIBILITIES DROPPING UNDER
1SM IN A FEW LOCATIONS. NOT EXPECTING WIDESPREAD DENSE FOG THIS
MORNING BUT WILL NEED TO MONITOR OBS OVER THE NEXT FEW HOURS. THE
FOG WILL LIFT THIS MORNING BUT WITH LITTLE CHANGE TO THE AIRMASS
FOG WILL BE POSSIBLE AGAIN TONIGHT INTO SUNDAY MORNING.
A FEW SHOWERS DEVELOPED ACROSS NORTHERN LAKE COUNTY IN NORTHEAST
IL LATE FRIDAY EVENING AND PERSISTED FOR A FEW HOURS BEFORE
DISSIPATING. OTHERWISE...CONVECTION HAS BEEN FOCUSED FURTHER WEST
EARLY THIS MORNING IN THE VICINITY OF THE LOW LEVEL JET. SOME OF
THIS ACTIVITY OVER EASTERN IA MAY ARRIVE ACROSS THE WESTERN CWA
LATER THIS MORNING...LIKELY IN A DECAYING FORM. BUT OTHER THAN AN
ISOLATED SHOWER...EXPECT THE NEXT SEVERAL HOURS TO BE MAINLY DRY.
CONFIDENCE REGARDING THUNDERSTORM CHANCES THIS AFTERNOON INTO
THIS EVENING IS LOW THOUGH THERE IS SOME CONSENSUS FOR DEVELOPMENT
BY EARLY AFTERNOON ACROSS WESTERN/NORTHWEST IL FROM REMNANTS OF
CONVECTION OVER EASTERN NEBRASKA/WESTERN IA. HOW FAR IT CONTINUES
EAST OR NORTHEAST BEFORE WEAKENING IS ANOTHER UNCERTAINTY. MADE NO
SIGNIFICANT CHANGES FOR TODAY MAINTAINING 30-40 POPS. TRENDS WILL
NEED TO BE MONITORED THRU THE MORNING. DEWPOINTS IN THE 70S AND
PRECIPITABLE WATER VALUES APPROACHING 2 INCHES WILL LEAD TO VERY
HEAVY RAIN WITH ANY THUNDERSTORMS THAT DO DEVELOP AND POSSIBLY
FLASH FLOODING...ESPECIALLY IF THE RAIN FALLS OVER HARDER HIT
AREAS FROM FRIDAY MORNING.
THE UPPER RIDGE THEN BUILDS ACROSS THE AREA TONIGHT AND SUNDAY AND
PRECIP CHANCES LOOK BELOW MENTIONABLE FROM LATE TONIGHT THROUGH
MONDAY MORNING. CAN/T COMPLETELY RULE OUT SOME ISOLATED ACTIVITY...
IN PARTICULAR ON A LAKE BREEZE SUNDAY AFTERNOON. A FRONTAL
BOUNDARY WILL MOVE ACROSS THE UPPER MIDWEST SUNDAY NIGHT INTO
MONDAY WITH SOME DIFFERENCES AS TO HOW FAR SOUTH THIS BOUNDARY
WILL SETTLE MONDAY AFTERNOON INTO MONDAY NIGHT. THIS WOULD LIKELY
BE THE NEXT CHANCE OF THUNDERSTORMS WITH THE GEM/ECMWF BOTH
PUSHING THE FRONT THROUGH MUCH OF THE CWA BY TUESDAY MORNING. THIS
BOUNDARY THEN MEANDERS NEAR THE IL/WI BORDER INTO THURSDAY WITH
THE POSSIBILITY OF A PROLONGED UNSETTLED PATTERN ACROSS THE AREA.
CLOUD COVER/CONVECTION TODAY WILL LIKELY KEEP TEMPS IN THE 80S...
THOUGH WITH THE URBAN AREAS STARTING FROM LOWER/MID 70S...ANY
LONGER PERIOD OF SUNSHINE TODAY COULD ALLOW A FEW PLACES TO TAG
90. TEMPS WILL WARM A FEW DEGREES SUNDAY BUT SOUTHEASTERLY WINDS
WILL KEEP THE LAKESHORE COOLER. MONDAY LOOKS TO BE THE BEST
CHANCE FOR TEMPS INTO THE LOWER 90S CWA WIDE BUT WILL BE DEPENDENT
ON CLOUD COVER AND TIMING/ARRIVAL OF ANY PRECIP. DEWPOINTS MAY
LOWER A FEW DEGREES...BACK INTO THE MID/UPPER 60S ACROSS PARTS OF
THE AREA SUNDAY. HEAT INDICES COULD RANGE FROM LOWER/MID 90S TO
100-105 FAR SOUTHWEST. DEWPOINTS THEN BACK INTO THE 70S EVERYWHERE
MONDAY WITH HEAT INDICES CLOSER TO 100-105 MOST AREAS WITH STILL
THE POTENTIAL TO REACH HEAT ADVISORY CRITERIA ACROSS THE FAR
SOUTHERN CWA MONDAY AFTERNOON. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* RAIN WITH A PERIOD OF THUNDER AND POSSIBLE IFR VISIBILITY
BETWEEN 19Z-21Z...WITH THE POTENTIAL FOR LINGERING SCATTERED
SHRA/TSRA INTO THE EVE.
* EAST-NORTHEAST WINDS SHIFTING SOUTHWEST WITH SHOWERS AND STORMS
THEN LIKELY BECOMING SOUTHEAST OR EAST AFTERWARD /NEAR 20Z/ AND
POTENTIALLY BEING AROUND 10 KT.
* POTENTIAL FOR IFR CIGS AND/OR VISIBILITY TONIGHT INTO SUNDAY
MORNING.
* LAKE BREEZE TURNING WINDS EASTERLY AROUND OR POSSIBLY ABOVE 10
KT SUNDAY.
//DISCUSSION...UPDATED 18Z...
AREA OF SHOWERS AND STORMS CONTINUES TO MOVE EASTWARD WITH A SLOW
WANING TREND...ESPECIALLY IN PART OF THE SEGMENT JUST UPSTREAM OF
ORD AND MDW. WHILE THAT IS THE CASE...INCREASED CONVERGENCE
BETWEEN THE OUTFLOW AND THE LAKE BREEZE IN UNCAPPED AIR WILL
LIKELY SPARK MORE STORMS. THIS ALSO COULD EXTEND THE TSRA TIMING.
SO FEEL COMFORTABLE WITH THE TSRA STILL INDICATED IN THE
CHICAGOLAND TAFS. STRATIFORM RAIN BEHIND THIS WILL LIKELY BE
ACCOMPANIED WITH MVFR CONDITIONS. SCATTERED SHOWERS AND STORMS ARE
POSSIBLE BEHIND THIS DURING THE LATTER HALF OF THE AFTERNOON INTO
THE EVENING IN THE CONTINUED MOISTURE RICH AIR MASS.
THE WIND DIRECTION WILL LIKELY TURN SOUTHWEST AS THE STORMS
PASS...AS ALL OBSERVATIONS SITES HAVE INDICATED THAT UPSTREAM AND
RADAR SHOW WELL-DEFINED OUTFLOW. THE SPEED OF THE OUTFLOW HAS
SLOWED SOME...SO THE DEGREE OF GUSTS AT CHICAGOLAND TAF SITES IS
EXPECTED TO BE LESS THAN 30 KT. THE WIND DIRECTION BEHIND THE
INITIAL PUSH OF STORMS MAY BECOME VARIABLE...BUT IS ANTICIPATED TO
TURN EAST OR SOUTHEAST BASED ON THE SYNOPTIC FLOW AND CLIMATOLOGY
FOR POST-THUNDERSTORM WINDS AT ORD.
THE MOISTURE IN THE LOW-LEVELS AIDED BY RAIN EARLY THIS AFTERNOON
WILL SET THE STAGE ONCE AGAIN FOR FOG AND LOW CIGS
TONIGHT...HOWEVER THE COVERAGE OF THIS IS DIFFICULT TO DETERMINE
AT THIS TIME.
A LAKE BREEZE LOOKS LIKELY ON SUNDAY AFTERNOON INTO NORTHEAST
ILLINOIS THAT WILL PROBABLY REACH BOTH ORD AND MDW.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH IN THUNDER OCCURRING. MEDIUM IN DURATION. LOW IN SHRA/TSRA
CHANCES THIS EVE.
* LOW IN WIND DIRECTION BETWEEN 19Z AND 21Z...MEDIUM IN WIND
CONDITIONS OTHERWISE...INCLUDING LAKE BREEZE TIMING ON SUNDAY.
* MEDIUM IN SOME FORM OF IFR RESTRICTION LATE TONIGHT INTO EARLY
SUNDAY MORNING. LOW ON WHETHER FOG AND/OR CIG.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA WITH
OCCASIONAL MVFR.
FRIDAY...VFR WITH SLIGHT CHANCE TSRA.
MTF
&&
.MARINE...
340 AM CDT
BROAD LOW PRESSURE REMAINS ACROSS THE MID MISSISSIPPI RIVER VALLEY
THIS MORNING WHILE STRONGER LOW PRESSURE ORGANIZES OVER THE CENTRAL
HIGH PLAINS. AN UPPER LOW SPINNING OVER THE NORTHWEST U.S. WILL HELP
KICK THE HIGH PLAINS LOW NORTHWARD INTO SUNDAY WHILE HIGH PRESSURE
MOVES FROM QUEBEC TO NEW ENGLAND AND THE MID-ATLANTIC STATES. EAST
TO NORTHEAST WINDS WILL CONTINUE ACROSS LAKE MICHIGAN TODAY BUT WILL
SHIFT TO THE SOUTHEAST INTO SUNDAY...WITH SPEEDS INCREASING
MODESTLY. THE MAIN TRACK OF LOW PRESSURE WILL REMAIN OFF TO THE
NORTHWEST OF THE LAKE INTO THE MIDDLE OF NEXT WEEK WHICH WILL KEEP A
SOUTHERLY WIND GOING...THOUGH SOUTHERN AREAS MAY SEE WINDS SHIFT
ONSHORE EACH AFTERNOON WHERE THE PRESSURE GRADIENT IS WEAKER. A
FRONTAL BOUNDARY IS EXPECTED TO DROP OVER NORTHERN PARTS OF THE LAKE
TOWARD MIDWEEK WHICH WOULD LEAD TO EAST OR NORTHEAST WINDS ACROSS
THE NORTH WITH SOUTHERLY WINDS CONTINUING SOUTH. MEDIUM RANGE
GUIDANCE CONFLICTS WITH HOW QUICKLY THIS FRONT MOVES ACROSS THE LAKE
AND THE STRENGTH OF COLD AIR BEHIND IT DURING THE MIDDLE OF NEXT WEEK
LEADING TO LOW FORECAST CONFIDENCE BY THAT TIME.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
109 PM CDT SAT AUG 23 2014
.DISCUSSION...
959 AM CDT
THE FORECAST HAS BEEN UPDATED TO REFLECT GREATER CLOUD COVER
AREAWIDE AND HIGHER POPS ACROSS MAINLY NORTH CENTRAL ILLINOIS
DURING THE EARLY-MID AFTERNOON.
A BROAD MESOSCALE CONVECTIVE SYSTEM WITH A LINE OF STORMS ON ITS
FRONT EDGE IS CURRENTLY ADVANCING EAST OVER THE MISSISSIPPI
RIVER AND FAR WESTERN ILLINOIS. THIS CONTINUES TO HOLD TOGETHER
WELL WITH ONLY SUBTLE CLOUD TOP WARMING AND NO FADE IN LIGHTNING
ACTIVITY OVER THE PAST COUPLE HOURS. THIS COMPLEX HAS BEEN ONGOING
FOR OVER NINE HOURS SO NOT SURPRISED TO SEE THAT THE RADAR LOOP
INDICATES THE LIKELY PRESENCE OF A CONVECTIVELY-INDUCED VORTICITY
MAXIMUM /MCV/ IN FAR EASTERN IA. THIS WITH A COLD POOL IS HELPING
TO USHER PUSH THE STORMS MORE EASTWARD THAN THE NORTHEAST MOVEMENT
OF THE PARENT SHORTWAVE WOULD INDICATE. DESPITE WHAT SHOULD BE A
GRADUAL FACE INTO THE EARLY AFTERNOON WITH THE UPPER SUPPORT
MOVING NORTHEAST AND A DECAYING LOW-LEVEL JET PER PROFILERS...2.2
INCH PWAT AIR /99TH PERCENTILE/ AHEAD OF THE MCV WILL LIKELY
SUPPORT SHOWERS AND SOME STORMS INTO NORTH CENTRAL ILLINOIS
BETWEEN NOON AND 3 PM. STILL SEEING SOME EMBEDDED HOURLY PRECIP
REPORTS OF A HALF TO ONE INCH WITH THIS...AND SOME OF THIS
EFFICIENCY COULD CERTAINLY OCCUR ALONG AND WEST OF I-39 DURING THE
EARLY AFTERNOON.
UNDER THE INFLUENCE OF WEAK UPPER LEVEL FLOW...THE MCV IS
FORECAST BY THE RAP AND NAM TO CONTINUE TO SLOW AS IT MOVES INTO
NORTH CENTRAL IL. DESTABILIZATION AHEAD OF IT MAY SUPPORT
ISOLATED OR SCATTERED SHOWERS/STORMS LATER THIS AFTERNOON FURTHER
EAST TOWARD CHICAGO AND THE I-57 CORRIDOR INTO NORTHWEST
INDIANA...BUT CONFIDENCE ON THIS IS LOW AS ANVIL SHIELD WILL
INHIBIT THE RATE OF WARMTH...WITH MOST GUIDANCE INDICATING THE
PRESENCE OF A CAP AND LOW-LEVEL FLOW OFF THE LAKE IN FAR NORTHEAST
IL.
MINOR TWEAKS MADE TO HOURLY TEMPERATURES AND DEW POINTS.
MTF
//PREV DISCUSSION...
327 AM...FORECAST CONCERNS INCLUDE THUNDERSTORM CHANCES/TIMING
THROUGH THE PERIOD ALONG WITH HIGH TEMPERATURES/HEAT INDICES
THROUGH MONDAY.
AREAS OF FOG CONTINUE TO DEVELOP WITH VISIBILITIES DROPPING UNDER
1SM IN A FEW LOCATIONS. NOT EXPECTING WIDESPREAD DENSE FOG THIS
MORNING BUT WILL NEED TO MONITOR OBS OVER THE NEXT FEW HOURS. THE
FOG WILL LIFT THIS MORNING BUT WITH LITTLE CHANGE TO THE AIRMASS
FOG WILL BE POSSIBLE AGAIN TONIGHT INTO SUNDAY MORNING.
A FEW SHOWERS DEVELOPED ACROSS NORTHERN LAKE COUNTY IN NORTHEAST
IL LATE FRIDAY EVENING AND PERSISTED FOR A FEW HOURS BEFORE
DISSIPATING. OTHERWISE...CONVECTION HAS BEEN FOCUSED FURTHER WEST
EARLY THIS MORNING IN THE VICINITY OF THE LOW LEVEL JET. SOME OF
THIS ACTIVITY OVER EASTERN IA MAY ARRIVE ACROSS THE WESTERN CWA
LATER THIS MORNING...LIKELY IN A DECAYING FORM. BUT OTHER THAN AN
ISOLATED SHOWER...EXPECT THE NEXT SEVERAL HOURS TO BE MAINLY DRY.
CONFIDENCE REGARDING THUNDERSTORM CHANCES THIS AFTERNOON INTO
THIS EVENING IS LOW THOUGH THERE IS SOME CONSENSUS FOR DEVELOPMENT
BY EARLY AFTERNOON ACROSS WESTERN/NORTHWEST IL FROM REMNANTS OF
CONVECTION OVER EASTERN NEBRASKA/WESTERN IA. HOW FAR IT CONTINUES
EAST OR NORTHEAST BEFORE WEAKENING IS ANOTHER UNCERTAINTY. MADE NO
SIGNIFICANT CHANGES FOR TODAY MAINTAINING 30-40 POPS. TRENDS WILL
NEED TO BE MONITORED THRU THE MORNING. DEWPOINTS IN THE 70S AND
PRECIPITABLE WATER VALUES APPROACHING 2 INCHES WILL LEAD TO VERY
HEAVY RAIN WITH ANY THUNDERSTORMS THAT DO DEVELOP AND POSSIBLY
FLASH FLOODING...ESPECIALLY IF THE RAIN FALLS OVER HARDER HIT
AREAS FROM FRIDAY MORNING.
THE UPPER RIDGE THEN BUILDS ACROSS THE AREA TONIGHT AND SUNDAY AND
PRECIP CHANCES LOOK BELOW MENTIONABLE FROM LATE TONIGHT THROUGH
MONDAY MORNING. CAN/T COMPLETELY RULE OUT SOME ISOLATED ACTIVITY...
IN PARTICULAR ON A LAKE BREEZE SUNDAY AFTERNOON. A FRONTAL
BOUNDARY WILL MOVE ACROSS THE UPPER MIDWEST SUNDAY NIGHT INTO
MONDAY WITH SOME DIFFERENCES AS TO HOW FAR SOUTH THIS BOUNDARY
WILL SETTLE MONDAY AFTERNOON INTO MONDAY NIGHT. THIS WOULD LIKELY
BE THE NEXT CHANCE OF THUNDERSTORMS WITH THE GEM/ECMWF BOTH
PUSHING THE FRONT THROUGH MUCH OF THE CWA BY TUESDAY MORNING. THIS
BOUNDARY THEN MEANDERS NEAR THE IL/WI BORDER INTO THURSDAY WITH
THE POSSIBILITY OF A PROLONGED UNSETTLED PATTERN ACROSS THE AREA.
CLOUD COVER/CONVECTION TODAY WILL LIKELY KEEP TEMPS IN THE 80S...
THOUGH WITH THE URBAN AREAS STARTING FROM LOWER/MID 70S...ANY
LONGER PERIOD OF SUNSHINE TODAY COULD ALLOW A FEW PLACES TO TAG
90. TEMPS WILL WARM A FEW DEGREES SUNDAY BUT SOUTHEASTERLY WINDS
WILL KEEP THE LAKESHORE COOLER. MONDAY LOOKS TO BE THE BEST
CHANCE FOR TEMPS INTO THE LOWER 90S CWA WIDE BUT WILL BE DEPENDENT
ON CLOUD COVER AND TIMING/ARRIVAL OF ANY PRECIP. DEWPOINTS MAY
LOWER A FEW DEGREES...BACK INTO THE MID/UPPER 60S ACROSS PARTS OF
THE AREA SUNDAY. HEAT INDICES COULD RANGE FROM LOWER/MID 90S TO
100-105 FAR SOUTHWEST. DEWPOINTS THEN BACK INTO THE 70S EVERYWHERE
MONDAY WITH HEAT INDICES CLOSER TO 100-105 MOST AREAS WITH STILL
THE POTENTIAL TO REACH HEAT ADVISORY CRITERIA ACROSS THE FAR
SOUTHERN CWA MONDAY AFTERNOON. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* RAIN WITH A PERIOD OF THUNDER AND POSSIBLE IFR VISIBILITY
BETWEEN 19Z-21Z...WITH THE POTENTIAL FOR LINGERING SCATTERED
SHRA/TSRA INTO THE EVE.
* EAST-NORTHEAST WINDS SHIFTING SOUTHWEST WITH SHOWERS AND STORMS
THEN LIKELY BECOMING SOUTHEAST OR EAST AFTERWARD /NEAR 20Z/ AND
POTENTIALLY BEING AROUND 10 KT.
* POTENTIAL FOR IFR CIGS AND/OR VISIBILITY TONIGHT INTO SUNDAY
MORNING.
* LAKE BREEZE TURNING WINDS EASTERLY AROUND OR POSSIBLY ABOVE 10
KT SUNDAY.
//DISCUSSION...UPDATED 18Z...
AREA OF SHOWERS AND STORMS CONTINUES TO MOVE EASTWARD WITH A SLOW
WANING TREND...ESPECIALLY IN PART OF THE SEGMENT JUST UPSTREAM OF
ORD AND MDW. WHILE THAT IS THE CASE...INCREASED CONVERGENCE
BETWEEN THE OUTFLOW AND THE LAKE BREEZE IN UNCAPPED AIR WILL
LIKELY SPARK MORE STORMS. THIS ALSO COULD EXTEND THE TSRA TIMING.
SO FEEL COMFORTABLE WITH THE TSRA STILL INDICATED IN THE
CHICAGOLAND TAFS. STRATIFORM RAIN BEHIND THIS WILL LIKELY BE
ACCOMPANIED WITH MVFR CONDITIONS. SCATTERED SHOWERS AND STORMS ARE
POSSIBLE BEHIND THIS DURING THE LATTER HALF OF THE AFTERNOON INTO
THE EVENING IN THE CONTINUED MOISTURE RICH AIR MASS.
THE WIND DIRECTION WILL LIKELY TURN SOUTHWEST AS THE STORMS
PASS...AS ALL OBSERVATIONS SITES HAVE INDICATED THAT UPSTREAM AND
RADAR SHOW WELL-DEFINED OUTFLOW. THE SPEED OF THE OUTFLOW HAS
SLOWED SOME...SO THE DEGREE OF GUSTS AT CHICAGOLAND TAF SITES IS
EXPECTED TO BE LESS THAN 30 KT. THE WIND DIRECTION BEHIND THE
INITIAL PUSH OF STORMS MAY BECOME VARIABLE...BUT IS ANTICIPATED TO
TURN EAST OR SOUTHEAST BASED ON THE SYNOPTIC FLOW AND CLIMATOLOGY
FOR POST-THUNDERSTORM WINDS AT ORD.
THE MOISTURE IN THE LOW-LEVELS AIDED BY RAIN EARLY THIS AFTERNOON
WILL SET THE STAGE ONCE AGAIN FOR FOG AND LOW CIGS
TONIGHT...HOWEVER THE COVERAGE OF THIS IS DIFFICULT TO DETERMINE
AT THIS TIME.
A LAKE BREEZE LOOKS LIKELY ON SUNDAY AFTERNOON INTO NORTHEAST
ILLINOIS THAT WILL PROBABLY REACH BOTH ORD AND MDW.
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH IN THUNDER OCCURRING. MEDIUM IN DURATION. LOW IN SHRA/TSRA
CHANCES THIS EVE.
* LOW IN WIND DIRECTION BETWEEN 19Z AND 21Z...MEDIUM IN WIND
CONDITIONS OTHERWISE...INCLUDING LAKE BREEZE TIMING ON SUNDAY.
* MEDIUM IN SOME FORM OF IFR RESTRICTION LATE TONIGHT INTO EARLY
SUNDAY MORNING. LOW ON WHETHER FOG AND/OR CIG.
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA WITH
OCCASIONAL MVFR.
FRIDAY...VFR WITH SLIGHT CHANCE TSRA.
MTF
&&
.MARINE...
340 AM CDT
BROAD LOW PRESSURE REMAINS ACROSS THE MID MISSISSIPPI RIVER VALLEY
THIS MORNING WHILE STRONGER LOW PRESSURE ORGANIZES OVER THE CENTRAL
HIGH PLAINS. AN UPPER LOW SPINNING OVER THE NORTHWEST U.S. WILL HELP
KICK THE HIGH PLAINS LOW NORTHWARD INTO SUNDAY WHILE HIGH PRESSURE
MOVES FROM QUEBEC TO NEW ENGLAND AND THE MID-ATLANTIC STATES. EAST
TO NORTHEAST WINDS WILL CONTINUE ACROSS LAKE MICHIGAN TODAY BUT WILL
SHIFT TO THE SOUTHEAST INTO SUNDAY...WITH SPEEDS INCREASING
MODESTLY. THE MAIN TRACK OF LOW PRESSURE WILL REMAIN OFF TO THE
NORTHWEST OF THE LAKE INTO THE MIDDLE OF NEXT WEEK WHICH WILL KEEP A
SOUTHERLY WIND GOING...THOUGH SOUTHERN AREAS MAY SEE WINDS SHIFT
ONSHORE EACH AFTERNOON WHERE THE PRESSURE GRADIENT IS WEAKER. A
FRONTAL BOUNDARY IS EXPECTED TO DROP OVER NORTHERN PARTS OF THE LAKE
TOWARD MIDWEEK WHICH WOULD LEAD TO EAST OR NORTHEAST WINDS ACROSS
THE NORTH WITH SOUTHERLY WINDS CONTINUING SOUTH. MEDIUM RANGE
GUIDANCE CONFLICTS WITH HOW QUICKLY THIS FRONT MOVES ACROSS THE LAKE
AND THE STRENGTH OF COLD AIR BEHIND IT DURING THE MIDDLE OF NEXT WEEK
LEADING TO LOW FORECAST CONFIDENCE BY THAT TIME.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1123 AM CDT SAT AUG 23 2014
.DISCUSSION...
959 AM CDT
THE FORECAST HAS BEEN UPDATED TO REFLECT GREATER CLOUD COVER
AREAWIDE AND HIGHER POPS ACROSS MAINLY NORTH CENTRAL ILLINOIS
DURING THE EARLY-MID AFTERNOON.
A BROAD MESOSCALE CONVECTIVE SYSTEM WITH A LINE OF STORMS ON ITS
FRONT EDGE IS CURRENTLY ADVANCING EAST OVER THE MISSISSIPPI
RIVER AND FAR WESTERN ILLINOIS. THIS CONTINUES TO HOLD TOGETHER
WELL WITH ONLY SUBTLE CLOUD TOP WARMING AND NO FADE IN LIGHTNING
ACTIVITY OVER THE PAST COUPLE HOURS. THIS COMPLEX HAS BEEN ONGOING
FOR OVER NINE HOURS SO NOT SURPRISED TO SEE THAT THE RADAR LOOP
INDICATES THE LIKELY PRESENCE OF A CONVECTIVELY-INDUCED VORTICITY
MAXIMUM /MCV/ IN FAR EASTERN IA. THIS WITH A COLD POOL IS HELPING
TO USHER PUSH THE STORMS MORE EASTWARD THAN THE NORTHEAST MOVEMENT
OF THE PARENT SHORTWAVE WOULD INDICATE. DESPITE WHAT SHOULD BE A
GRADUAL FACE INTO THE EARLY AFTERNOON WITH THE UPPER SUPPORT
MOVING NORTHEAST AND A DECAYING LOW-LEVEL JET PER PROFILERS...2.2
INCH PWAT AIR /99TH PERCENTILE/ AHEAD OF THE MCV WILL LIKELY
SUPPORT SHOWERS AND SOME STORMS INTO NORTH CENTRAL ILLINOIS
BETWEEN NOON AND 3 PM. STILL SEEING SOME EMBEDDED HOURLY PRECIP
REPORTS OF A HALF TO ONE INCH WITH THIS...AND SOME OF THIS
EFFICIENCY COULD CERTAINLY OCCUR ALONG AND WEST OF I-39 DURING THE
EARLY AFTERNOON.
UNDER THE INFLUENCE OF WEAK UPPER LEVEL FLOW...THE MCV IS
FORECAST BY THE RAP AND NAM TO CONTINUE TO SLOW AS IT MOVES INTO
NORTH CENTRAL IL. DESTABILIZATION AHEAD OF IT MAY SUPPORT
ISOLATED OR SCATTERED SHOWERS/STORMS LATER THIS AFTERNOON FURTHER
EAST TOWARD CHICAGO AND THE I-57 CORRIDOR INTO NORTHWEST
INDIANA...BUT CONFIDENCE ON THIS IS LOW AS ANVIL SHIELD WILL
INHIBIT THE RATE OF WARMTH...WITH MOST GUIDANCE INDICATING THE
PRESENCE OF A CAP AND LOW-LEVEL FLOW OFF THE LAKE IN FAR NORTHEAST
IL.
MINOR TWEAKS MADE TO HOURLY TEMPERATURES AND DEW POINTS.
MTF
//PREV DISCUSSION...
327 AM...FORECAST CONCERNS INCLUDE THUNDERSTORM CHANCES/TIMING
THROUGH THE PERIOD ALONG WITH HIGH TEMPERATURES/HEAT INDICES
THROUGH MONDAY.
AREAS OF FOG CONTINUE TO DEVELOP WITH VISIBILITIES DROPPING UNDER
1SM IN A FEW LOCATIONS. NOT EXPECTING WIDESPREAD DENSE FOG THIS
MORNING BUT WILL NEED TO MONITOR OBS OVER THE NEXT FEW HOURS. THE
FOG WILL LIFT THIS MORNING BUT WITH LITTLE CHANGE TO THE AIRMASS
FOG WILL BE POSSIBLE AGAIN TONIGHT INTO SUNDAY MORNING.
A FEW SHOWERS DEVELOPED ACROSS NORTHERN LAKE COUNTY IN NORTHEAST
IL LATE FRIDAY EVENING AND PERSISTED FOR A FEW HOURS BEFORE
DISSIPATING. OTHERWISE...CONVECTION HAS BEEN FOCUSED FURTHER WEST
EARLY THIS MORNING IN THE VICINITY OF THE LOW LEVEL JET. SOME OF
THIS ACTIVITY OVER EASTERN IA MAY ARRIVE ACROSS THE WESTERN CWA
LATER THIS MORNING...LIKELY IN A DECAYING FORM. BUT OTHER THAN AN
ISOLATED SHOWER...EXPECT THE NEXT SEVERAL HOURS TO BE MAINLY DRY.
CONFIDENCE REGARDING THUNDERSTORM CHANCES THIS AFTERNOON INTO
THIS EVENING IS LOW THOUGH THERE IS SOME CONSENSUS FOR DEVELOPMENT
BY EARLY AFTERNOON ACROSS WESTERN/NORTHWEST IL FROM REMNANTS OF
CONVECTION OVER EASTERN NEBRASKA/WESTERN IA. HOW FAR IT CONTINUES
EAST OR NORTHEAST BEFORE WEAKENING IS ANOTHER UNCERTAINTY. MADE NO
SIGNIFICANT CHANGES FOR TODAY MAINTAINING 30-40 POPS. TRENDS WILL
NEED TO BE MONITORED THRU THE MORNING. DEWPOINTS IN THE 70S AND
PRECIPITABLE WATER VALUES APPROACHING 2 INCHES WILL LEAD TO VERY
HEAVY RAIN WITH ANY THUNDERSTORMS THAT DO DEVELOP AND POSSIBLY
FLASH FLOODING...ESPECIALLY IF THE RAIN FALLS OVER HARDER HIT
AREAS FROM FRIDAY MORNING.
THE UPPER RIDGE THEN BUILDS ACROSS THE AREA TONIGHT AND SUNDAY AND
PRECIP CHANCES LOOK BELOW MENTIONABLE FROM LATE TONIGHT THROUGH
MONDAY MORNING. CAN/T COMPLETELY RULE OUT SOME ISOLATED ACTIVITY...
IN PARTICULAR ON A LAKE BREEZE SUNDAY AFTERNOON. A FRONTAL
BOUNDARY WILL MOVE ACROSS THE UPPER MIDWEST SUNDAY NIGHT INTO
MONDAY WITH SOME DIFFERENCES AS TO HOW FAR SOUTH THIS BOUNDARY
WILL SETTLE MONDAY AFTERNOON INTO MONDAY NIGHT. THIS WOULD LIKELY
BE THE NEXT CHANCE OF THUNDERSTORMS WITH THE GEM/ECMWF BOTH
PUSHING THE FRONT THROUGH MUCH OF THE CWA BY TUESDAY MORNING. THIS
BOUNDARY THEN MEANDERS NEAR THE IL/WI BORDER INTO THURSDAY WITH
THE POSSIBILITY OF A PROLONGED UNSETTLED PATTERN ACROSS THE AREA.
CLOUD COVER/CONVECTION TODAY WILL LIKELY KEEP TEMPS IN THE 80S...
THOUGH WITH THE URBAN AREAS STARTING FROM LOWER/MID 70S...ANY
LONGER PERIOD OF SUNSHINE TODAY COULD ALLOW A FEW PLACES TO TAG
90. TEMPS WILL WARM A FEW DEGREES SUNDAY BUT SOUTHEASTERLY WINDS
WILL KEEP THE LAKESHORE COOLER. MONDAY LOOKS TO BE THE BEST
CHANCE FOR TEMPS INTO THE LOWER 90S CWA WIDE BUT WILL BE DEPENDENT
ON CLOUD COVER AND TIMING/ARRIVAL OF ANY PRECIP. DEWPOINTS MAY
LOWER A FEW DEGREES...BACK INTO THE MID/UPPER 60S ACROSS PARTS OF
THE AREA SUNDAY. HEAT INDICES COULD RANGE FROM LOWER/MID 90S TO
100-105 FAR SOUTHWEST. DEWPOINTS THEN BACK INTO THE 70S EVERYWHERE
MONDAY WITH HEAT INDICES CLOSER TO 100-105 MOST AREAS WITH STILL
THE POTENTIAL TO REACH HEAT ADVISORY CRITERIA ACROSS THE FAR
SOUTHERN CWA MONDAY AFTERNOON. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* TEMPORARY MVFR CIGS...ABOVE 1500FT...INTO THIS AFTERNOON.
* EAST TO NORTHEAST WINDS THROUGH THE DAY WITH SPEEDS POSSIBLY
APPROACHING 10 KT...WITH A CHANCE WINDS COULD GET DISRUPTED IN
DIRECTION BY SHRA/TSRA.
* TEMPORARY SHRA LIKELY WITHIN THE 19Z-22Z WINDOW WITH THE
POSSIBILITY OF TSRA.
* CHANCE FOR REDUCED CIGS/VSBY OVERNIGHT.
MTF/MDB
//DISCUSSION...UPDATED 16Z...
AREA OF SHOWERS AND STORMS CONTINUE TO DRIVE ITSELF EASTWARD INTO
NORTH CENTRAL IL AS OF 16Z. THIS SHOULD CONTINUE TO MOVE
EAST...WITH AN EXPECTATION OF SOME DISSIPATION IN COVERAGE. THAT
SAID...INTENSITY MAY ACTUALLY START TO INCREASE FURTHER EAST AS
THE AREA MOVES INTO MORE UNSTABLE AIR. SO MAY NEED TO ADD TSRA
MENTION TO CHICAGOLAND TAF SITES.
MTF
PREV DISCUSSION...UPDATED 12Z...
WEAK LOW LEVEL FLOW FROM LAKE MICHIGAN COMBINED WITH THE VERY
MOIST AIRMASS HAS ALLOWED STRATUS/FOG TO SLOWLY PUSH INLAND THIS
MORNING. WITH ABUNDANT CIRRUS OVERHEAD WITH MORE UPSTREAM FROM
CONVECTION ACROSS IOWA IMPROVEMENT MAY BE VERY SLOW THIS MORNING
SO ADJUSTMENTS MAY BE NEEDED OVER THE NEXT FEW HOURS. WITH
GYY/MDW/RFD BEING ON THE FRINGES OF THE IFR IMPROVEMENT MAY BE
STEADIER THERE WITH ORD/DPA LIKELY BEING THE SLOWEST. DO EXPECT
THAT VFR WILL RETURN HOWEVER. EASTERLY WINDS WILL BE IN PLACE
THROUGH THE DAY WITH SPEEDS EXPECTED TO BE UNDER 10 KT.
SPOTTY CONVECTION HAS BEEN FESTERING OVER FAR EASTERN IOWA AHEAD
OF A MUCH LARGER COMPLEX ACROSS CENTRAL IOWA. THIS ACTIVITY IS
MOVING NORTHEASTWARD BUT STEERING FLOW WOULD TAKE IT MORE EASTERLY
THOUGH AT LEAST SOME DECAY IS POSSIBLE IN THE NEAR TERM. HAVE LOW
CONFIDENCE IN HOW CONVECTION PLAYS OUT THE REST OF THE DAY BUT AT
LEAST SCATTERED TSRA IS POSSIBLE AS THE PARENT FORCING DRIFTS
TOWARD THE AREA LATER TODAY. THIS POINTS TO THE AFTERNOON/EVENING
BEING THE MOST LIKELY PERIOD FOR STORMS BUT THE BEST CHANCES MAY
BE FOCUSED WEST OF THE TERMINALS. GIVEN THE UNCERTAINTY WILL KEEP
THE TAFS DRY FOR NOW BUT EXPECT THAT RFD MAY NEED A MENTION OF
TSRA ADDED BEFORE TOO LONG. WITH CONTINUED WEAK FLOW AND HIGH
HUMIDITY MORE FOG AND STRATUS WILL BE POSSIBLE TONIGHT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM-HIGH IN OCCASIONAL MVFR CIGS.
* MEDIUM IN WIND DIRECTION AND SPEED.
* MEDIUM IN SHRA AND LOW IN TSRA OCCURRING AT THE AIRFIELDS.
* MEDIUM THAT THERE WILL BE SOME SORT OF CIG/VSBY REDUCTION
TONIGHT.
MTF/MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA WITH
OCCASIONAL MVFR.
FRIDAY...VFR WITH SLIGHT CHANCE TSRA.
MDB
&&
.MARINE...
340 AM CDT
BROAD LOW PRESSURE REMAINS ACROSS THE MID MISSISSIPPI RIVER VALLEY
THIS MORNING WHILE STRONGER LOW PRESSURE ORGANIZES OVER THE CENTRAL
HIGH PLAINS. AN UPPER LOW SPINNING OVER THE NORTHWEST U.S. WILL HELP
KICK THE HIGH PLAINS LOW NORTHWARD INTO SUNDAY WHILE HIGH PRESSURE
MOVES FROM QUEBEC TO NEW ENGLAND AND THE MID-ATLANTIC STATES. EAST
TO NORTHEAST WINDS WILL CONTINUE ACROSS LAKE MICHIGAN TODAY BUT WILL
SHIFT TO THE SOUTHEAST INTO SUNDAY...WITH SPEEDS INCREASING
MODESTLY. THE MAIN TRACK OF LOW PRESSURE WILL REMAIN OFF TO THE
NORTHWEST OF THE LAKE INTO THE MIDDLE OF NEXT WEEK WHICH WILL KEEP A
SOUTHERLY WIND GOING...THOUGH SOUTHERN AREAS MAY SEE WINDS SHIFT
ONSHORE EACH AFTERNOON WHERE THE PRESSURE GRADIENT IS WEAKER. A
FRONTAL BOUNDARY IS EXPECTED TO DROP OVER NORTHERN PARTS OF THE LAKE
TOWARD MIDWEEK WHICH WOULD LEAD TO EAST OR NORTHEAST WINDS ACROSS
THE NORTH WITH SOUTHERLY WINDS CONTINUING SOUTH. MEDIUM RANGE
GUIDANCE CONFLICTS WITH HOW QUICKLY THIS FRONT MOVES ACROSS THE LAKE
AND THE STRENGTH OF COLD AIR BEHIND IT DURING THE MIDDLE OF NEXT WEEK
LEADING TO LOW FORECAST CONFIDENCE BY THAT TIME.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
SATURDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
959 AM CDT SAT AUG 23 2014
.DISCUSSION...
959 AM CDT
THE FORECAST HAS BEEN UPDATED TO REFLECT GREATER CLOUD COVER
AREAWIDE AND HIGHER POPS ACROSS MAINLY NORTH CENTRAL ILLINOIS
DURING THE EARLY-MID AFTERNOON.
A BROAD MESOSCALE CONVECTIVE SYSTEM WITH A LINE OF STORMS ON ITS
FRONT EDGE IS CURRENTLY ADVANCING EAST OVER THE MISSISSIPPI
RIVER AND FAR WESTERN ILLINOIS. THIS CONTINUES TO HOLD TOGETHER
WELL WITH ONLY SUBTLE CLOUD TOP WARMING AND NO FADE IN LIGHTNING
ACTIVITY OVER THE PAST COUPLE HOURS. THIS COMPLEX HAS BEEN ONGOING
FOR OVER NINE HOURS SO NOT SURPRISED TO SEE THAT THE RADAR LOOP
INDICATES THE LIKELY PRESENCE OF A CONVECTIVELY-INDUCED VORTICITY
MAXIMUM /MCV/ IN FAR EASTERN IA. THIS WITH A COLD POOL IS HELPING
TO USHER PUSH THE STORMS MORE EASTWARD THAN THE NORTHEAST MOVEMENT
OF THE PARENT SHORTWAVE WOULD INDICATE. DESPITE WHAT SHOULD BE A
GRADUAL FACE INTO THE EARLY AFTERNOON WITH THE UPPER SUPPORT
MOVING NORTHEAST AND A DECAYING LOW-LEVEL JET PER PROFILERS...2.2
INCH PWAT AIR /99TH PERCENTILE/ AHEAD OF THE MCV WILL LIKELY
SUPPORT SHOWERS AND SOME STORMS INTO NORTH CENTRAL ILLINOIS
BETWEEN NOON AND 3 PM. STILL SEEING SOME EMBEDDED HOURLY PRECIP
REPORTS OF A HALF TO ONE INCH WITH THIS...AND SOME OF THIS
EFFICIENCY COULD CERTAINLY OCCUR ALONG AND WEST OF I-39 DURING THE
EARLY AFTERNOON.
UNDER THE INFLUENCE OF WEAK UPPER LEVEL FLOW...THE MCV IS
FORECAST BY THE RAP AND NAM TO CONTINUE TO SLOW AS IT MOVES INTO
NORTH CENTRAL IL. DESTABILIZATION AHEAD OF IT MAY SUPPORT
ISOLATED OR SCATTERED SHOWERS/STORMS LATER THIS AFTERNOON FURTHER
EAST TOWARD CHICAGO AND THE I-57 CORRIDOR INTO NORTHWEST
INDIANA...BUT CONFIDENCE ON THIS IS LOW AS ANVIL SHIELD WILL
INHIBIT THE RATE OF WARMTH...WITH MOST GUIDANCE INDICATING THE
PRESENCE OF A CAP AND LOW-LEVEL FLOW OFF THE LAKE IN FAR NORTHEAST
IL.
MINOR TWEAKS MADE TO HOURLY TEMPERATURES AND DEW POINTS.
MTF
&&
.PREV DISCUSSION...
327 AM...FORECAST CONCERNS INCLUDE THUNDERSTORM CHANCES/TIMING
THROUGH THE PERIOD ALONG WITH HIGH TEMPERATURES/HEAT INDICES
THROUGH MONDAY.
AREAS OF FOG CONTINUE TO DEVELOP WITH VISIBILITIES DROPPING UNDER
1SM IN A FEW LOCATIONS. NOT EXPECTING WIDESPREAD DENSE FOG THIS
MORNING BUT WILL NEED TO MONITOR OBS OVER THE NEXT FEW HOURS. THE
FOG WILL LIFT THIS MORNING BUT WITH LITTLE CHANGE TO THE AIRMASS
FOG WILL BE POSSIBLE AGAIN TONIGHT INTO SUNDAY MORNING.
A FEW SHOWERS DEVELOPED ACROSS NORTHERN LAKE COUNTY IN NORTHEAST
IL LATE FRIDAY EVENING AND PERSISTED FOR A FEW HOURS BEFORE
DISSIPATING. OTHERWISE...CONVECTION HAS BEEN FOCUSED FURTHER WEST
EARLY THIS MORNING IN THE VICINITY OF THE LOW LEVEL JET. SOME OF
THIS ACTIVITY OVER EASTERN IA MAY ARRIVE ACROSS THE WESTERN CWA
LATER THIS MORNING...LIKELY IN A DECAYING FORM. BUT OTHER THAN AN
ISOLATED SHOWER...EXPECT THE NEXT SEVERAL HOURS TO BE MAINLY DRY.
CONFIDENCE REGARDING THUNDERSTORM CHANCES THIS AFTERNOON INTO
THIS EVENING IS LOW THOUGH THERE IS SOME CONSENSUS FOR DEVELOPMENT
BY EARLY AFTERNOON ACROSS WESTERN/NORTHWEST IL FROM REMNANTS OF
CONVECTION OVER EASTERN NEBRASKA/WESTERN IA. HOW FAR IT CONTINUES
EAST OR NORTHEAST BEFORE WEAKENING IS ANOTHER UNCERTAINTY. MADE NO
SIGNIFICANT CHANGES FOR TODAY MAINTAINING 30-40 POPS. TRENDS WILL
NEED TO BE MONITORED THRU THE MORNING. DEWPOINTS IN THE 70S AND
PRECIPITABLE WATER VALUES APPROACHING 2 INCHES WILL LEAD TO VERY
HEAVY RAIN WITH ANY THUNDERSTORMS THAT DO DEVELOP AND POSSIBLY
FLASH FLOODING...ESPECIALLY IF THE RAIN FALLS OVER HARDER HIT
AREAS FROM FRIDAY MORNING.
THE UPPER RIDGE THEN BUILDS ACROSS THE AREA TONIGHT AND SUNDAY AND
PRECIP CHANCES LOOK BELOW MENTIONABLE FROM LATE TONIGHT THROUGH
MONDAY MORNING. CAN/T COMPLETELY RULE OUT SOME ISOLATED ACTIVITY...
IN PARTICULAR ON A LAKE BREEZE SUNDAY AFTERNOON. A FRONTAL
BOUNDARY WILL MOVE ACROSS THE UPPER MIDWEST SUNDAY NIGHT INTO
MONDAY WITH SOME DIFFERENCES AS TO HOW FAR SOUTH THIS BOUNDARY
WILL SETTLE MONDAY AFTERNOON INTO MONDAY NIGHT. THIS WOULD LIKELY
BE THE NEXT CHANCE OF THUNDERSTORMS WITH THE GEM/ECMWF BOTH
PUSHING THE FRONT THROUGH MUCH OF THE CWA BY TUESDAY MORNING. THIS
BOUNDARY THEN MEANDERS NEAR THE IL/WI BORDER INTO THURSDAY WITH
THE POSSIBILITY OF A PROLONGED UNSETTLED PATTERN ACROSS THE AREA.
CLOUD COVER/CONVECTION TODAY WILL LIKELY KEEP TEMPS IN THE 80S...
THOUGH WITH THE URBAN AREAS STARTING FROM LOWER/MID 70S...ANY
LONGER PERIOD OF SUNSHINE TODAY COULD ALLOW A FEW PLACES TO TAG
90. TEMPS WILL WARM A FEW DEGREES SUNDAY BUT SOUTHEASTERLY WINDS
WILL KEEP THE LAKESHORE COOLER. MONDAY LOOKS TO BE THE BEST
CHANCE FOR TEMPS INTO THE LOWER 90S CWA WIDE BUT WILL BE DEPENDENT
ON CLOUD COVER AND TIMING/ARRIVAL OF ANY PRECIP. DEWPOINTS MAY
LOWER A FEW DEGREES...BACK INTO THE MID/UPPER 60S ACROSS PARTS OF
THE AREA SUNDAY. HEAT INDICES COULD RANGE FROM LOWER/MID 90S TO
100-105 FAR SOUTHWEST. DEWPOINTS THEN BACK INTO THE 70S EVERYWHERE
MONDAY WITH HEAT INDICES CLOSER TO 100-105 MOST AREAS WITH STILL
THE POTENTIAL TO REACH HEAT ADVISORY CRITERIA ACROSS THE FAR
SOUTHERN CWA MONDAY AFTERNOON. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* MVFR VISIBILITY AND CIG IMPROVING BY 15Z-16Z.
* EAST TO NORTHEAST WINDS THROUGH THE DAY WITH SPEEDS POSSIBLY
APPROACHING 10 KT.
* LOW CHANCE FOR SHRA/TSRA...ESPECIALLY LATE THIS AFTERNOON AND
EARLY THIS EVE.
* CHANCE FOR REDUCED CIGS/VSBY OVERNIGHT.
MTF/MDB
//DISCUSSION...UPDATED 14Z...
CIGS AND VISBYS HAVE RAPIDLY IMPROVED OVER ORD AND MDW...WITH THE
GREATER RESTRICTIONS UNDER MORE STABILITY JUST TO THE NORTH OF
ORD. REGARDING WIND SPEED THIS AFTERNOON...VAD WIND PROFILERS ARE
INDICATING 10 KT OF EASTERLY FLOW AROUND 2000 FT WHICH WILL BE IN
THE MIXED LAYER THIS AFTERNOON BASED ON TEMPERATURE FORECASTS. SO
MAY SEE AT LEAST SPORADIC 10 KT WINDS 18Z AND AFTER. AS FOR
STORMS NEAR THE MISSISSIPPI RIVER THIS SHOULD CONTINUE TO VERY
SLOWLY FADE AS IT MOVES EAST-NORTHEAST. HAVE ADDED VCSH MENTION TO
RFD AT THIS TIME AND MAY HAVE TO MENTION SHOWERS WITH TEMPORARY
THUNDER DEPENDING ON OBSERVATIONAL AND LIGHTNING TRENDS.
MTF
PREV DISCUSSION...UPDATED 12Z...
WEAK LOW LEVEL FLOW FROM LAKE MICHIGAN COMBINED WITH THE VERY
MOIST AIRMASS HAS ALLOWED STRATUS/FOG TO SLOWLY PUSH INLAND THIS
MORNING. WITH ABUNDANT CIRRUS OVERHEAD WITH MORE UPSTREAM FROM
CONVECTION ACROSS IOWA IMPROVEMENT MAY BE VERY SLOW THIS MORNING
SO ADJUSTMENTS MAY BE NEEDED OVER THE NEXT FEW HOURS. WITH
GYY/MDW/RFD BEING ON THE FRINGES OF THE IFR IMPROVEMENT MAY BE
STEADIER THERE WITH ORD/DPA LIKELY BEING THE SLOWEST. DO EXPECT
THAT VFR WILL RETURN HOWEVER. EASTERLY WINDS WILL BE IN PLACE
THROUGH THE DAY WITH SPEEDS EXPECTED TO BE UNDER 10 KT.
SPOTTY CONVECTION HAS BEEN FESTERING OVER FAR EASTERN IOWA AHEAD
OF A MUCH LARGER COMPLEX ACROSS CENTRAL IOWA. THIS ACTIVITY IS
MOVING NORTHEASTWARD BUT STEERING FLOW WOULD TAKE IT MORE EASTERLY
THOUGH AT LEAST SOME DECAY IS POSSIBLE IN THE NEAR TERM. HAVE LOW
CONFIDENCE IN HOW CONVECTION PLAYS OUT THE REST OF THE DAY BUT AT
LEAST SCATTERED TSRA IS POSSIBLE AS THE PARENT FORCING DRIFTS
TOWARD THE AREA LATER TODAY. THIS POINTS TO THE AFTERNOON/EVENING
BEING THE MOST LIKELY PERIOD FOR STORMS BUT THE BEST CHANCES MAY
BE FOCUSED WEST OF THE TERMINALS. GIVEN THE UNCERTAINTY WILL KEEP
THE TAFS DRY FOR NOW BUT EXPECT THAT RFD MAY NEED A MENTION OF
TSRA ADDED BEFORE TOO LONG. WITH CONTINUED WEAK FLOW AND HIGH
HUMIDITY MORE FOG AND STRATUS WILL BE POSSIBLE TONIGHT.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH IN CIGS AND VISIBILITY IMPROVING THROUGH MID-MORNING.
* HIGH IN WIND DIRECTION AND MEDIUM IN WIND SPEED FORECAST THROUGH
TODAY.
* MEDIUM THAT POTENTIAL FOR SHRA/TSRA IS LOW THROUGH THE DAY.
* MEDIUM THAT THERE WILL BE SOME SORT OF CIG/VSBY REDUCTION
TONIGHT.
MTF/MDB
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR POSSIBLE.
MONDAY THROUGH THURSDAY...PERIODIC CHANCES FOR SHRA/TSRA WITH
OCCASIONAL MVFR.
FRIDAY...VFR WITH SLIGHT CHANCE TSRA.
MDB
&&
.MARINE...
340 AM CDT
BROAD LOW PRESSURE REMAINS ACROSS THE MID MISSISSIPPI RIVER VALLEY
THIS MORNING WHILE STRONGER LOW PRESSURE ORGANIZES OVER THE CENTRAL
HIGH PLAINS. AN UPPER LOW SPINNING OVER THE NORTHWEST U.S. WILL HELP
KICK THE HIGH PLAINS LOW NORTHWARD INTO SUNDAY WHILE HIGH PRESSURE
MOVES FROM QUEBEC TO NEW ENGLAND AND THE MID-ATLANTIC STATES. EAST
TO NORTHEAST WINDS WILL CONTINUE ACROSS LAKE MICHIGAN TODAY BUT WILL
SHIFT TO THE SOUTHEAST INTO SUNDAY...WITH SPEEDS INCREASING
MODESTLY. THE MAIN TRACK OF LOW PRESSURE WILL REMAIN OFF TO THE
NORTHWEST OF THE LAKE INTO THE MIDDLE OF NEXT WEEK WHICH WILL KEEP A
SOUTHERLY WIND GOING...THOUGH SOUTHERN AREAS MAY SEE WINDS SHIFT
ONSHORE EACH AFTERNOON WHERE THE PRESSURE GRADIENT IS WEAKER. A
FRONTAL BOUNDARY IS EXPECTED TO DROP OVER NORTHERN PARTS OF THE LAKE
TOWARD MIDWEEK WHICH WOULD LEAD TO EAST OR NORTHEAST WINDS ACROSS
THE NORTH WITH SOUTHERLY WINDS CONTINUING SOUTH. MEDIUM RANGE
GUIDANCE CONFLICTS WITH HOW QUICKLY THIS FRONT MOVES ACROSS THE LAKE
AND THE STRENGTH OF COLD AIR BEHIND IT DURING THE MIDDLE OF NEXT WEEK
LEADING TO LOW FORECAST CONFIDENCE BY THAT TIME.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 3 PM
SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
735 PM EDT SUN AUG 24 2014
.SYNOPSIS...
ISSUED AT 339 PM EDT SUN AUG 24 2014
AN UPPER LEVEL RIDGE WILL PROVIDE DRY CONDITIONS TO THE REGION
TONIGHT. WARM AND HUMID AIR WILL BE DRAWN NORTHWARD ACROSS THE
REGION TONIGHT INTO MONDAY IN ADVANCE OF AN UPPER LEVEL
DISTURBANCE TRACKING OUT OF THE PLAINS. AN ISOLATED SHOWER OR
THUNDERSTORM IS POSSIBLE ON MONDAY...BUT A FRONTAL BOUNDARY
ASSOCIATED WITH THIS DISTURBANCE WILL INCREASE THE CHANCE OF
SHOWERS AND THUNDERSTORMS BY TUESDAY. LOW TEMPERATURES TONIGHT
WILL DROP INTO THE MID AND UPPER 60S. HIGH TEMPERATURES ON MONDAY
WILL RANGE FROM THE MID 80S IN CENTRAL LOWER MICHIGAN...TO THE
LOWER 90S ACROSS NORTHEAST ILLINOIS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 339 PM EDT SUN AUG 24 2014
MID/UPPER LEVEL RIDGING TO PERSIST ACROSS THE REGION TONIGHT...WITH
PRIMARY SHORT WAVE TRACK FROM THE NORTHERN/CENTRAL PLAINS INTO
THE WESTERN/NORTHERN GREAT LAKES. AS HAS BEEN THE CASE OVER THE
PAST FEW DAYS...EASTERLY FLOW REGIME HAS BEEN CONDUCIVE FOR NARROW
ZONES OF WEAK CONVERGENCE...THE MOST DISTINCT THIS AFTERNOON
ROUGHLY FROM KEKM TO JUST NORTH OF KAOH. THE MOST UNSTABLE
CONDITIONS ARE ACROSS THE SOUTHWEST PORTIONS OF THE CWA. LITTLE IN
THE WAY OF ANY SYNOPTIC FORCING FOR VERTICAL MOTION NOTED THIS
AFTERNOON DUE TO PERSISTENCE OF UPPER RIDGING...ALTHOUGH AN
ISOLATED SHOWER OR STORM MAY TRY TO DEVELOP ALONG THE
AFOREMENTIONED CONVERGENCE ZONE WHERE SOME SLIGHTLY BETTER GROWTH
HAS BEEN NOTED IN AFTERNOON CU FIELD. CONFIDENCE IN OCCURRENCE AND
EXPECTED VERY LIMITED COVERAGE TO ANY CONVECTIVE DEVELOPMENT
PRECLUDES ANY ZFP MENTION. A SIMILAR SETUP IN STAGNANT PATTERN
TONIGHT SHOULD YIELD SOME PATCHY FOG AND STRATUS THROUGH EARLY
MONDAY MORNING.
UPPER LEVEL LOW CENTERED ACROSS THE NORTHERN HIGH PLAINS WILL LIFT
NORTHEAST INTO ONTARIO BY MONDAY EVENING. AN AXIS OF STRONGER
SOUTHWESTERLY LOW LEVEL FLOW WILL ALLOW FOR STRONG MOISTURE
TRANSPORT FROM THE MID MS VALLEY INTO THE NORTHERN GREAT LAKES
TONIGHT WHERE BEST CHANCES OF SHOWERS AND THUNDERSTORMS WILL RESIDE.
EVOLUTION OF THIS PATTERN WILL ALLOW FOR SLIGHT DEAMPLIFICATION OF
UPPER RIDGING ACROSS THE GREAT LAKES...AND NOT COMPLETELY OUT OF THE
QUESTION A REMNANT CONVECTIVE VORT COULD DROP SOUTHEAST INTO THE
SOUTHERN GREAT LAKES DURING THE DAY MONDAY. LOW LEVEL ANTICYCLONE
SHIFTING SOUTHEAST ACROSS THE MID ATLANTIC STATES SHOULD ALLOW FOR
SOME LOW LEVEL VEERING AND WARM/MOIST ADVECTION BACK INTO LOCAL
AREA...SETTING UP VERY UNSTABLE CONDITIONS FOR MONDAY. OUTSIDE OF
REMNANT FORCING FROM UPSTREAM CONVECTION TO THE NORTHWEST...NOT
MUCH TO KEY IN ON FOR FORCING MONDAY. HOWEVER...GIVEN SLIGHTLY
SUPPRESSED NATURE OF UPPER RIDGE...AND VERY UNSTABLE
CONDITIONS...DID INCLUDE SOME SLIGHT CHANCE TSRA POPS ACROSS
MAINLY NORTHERN HALF INTO EASTERN PORTIONS OF FORECAST AREA FOR
MONDAY.
WITH THE RETURN WARM/MOIST ADVECTION TONIGHT INTO EARLY
MONDAY...SFC DEW POINTS SHOULD CREEP BACK INTO THE LOWER TO MID 70S
WHICH WOULD YIELD PEAK AFTERNOON HEAT INDICES FROM THE MID TO
UPPER 90S WEST...TO THE LOWER 90S EAST ON MONDAY. AREAS ACROSS
THE FAR WEST/SOUTHWEST COULD CREEP CLOSE TO HEAT ADVISORY
CRITERIA...BUT GIVEN MARGINAL NATURE AND STILL SOME QUESTIONS
SURROUNDING LOW STRATUS/HIGH CLOUD EVOLUTION TONIGHT INTO EARLY
MONDAY...WILL HOLD OFF FOR NOW.
&&
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 339 PM EDT SUN AUG 24 2014
A RIDGE FLATTENING SHORTWAVE TROUGH PROPAGATING NORTHEAST INTO
ONTARIO/WESTERN QUEBEC TO START THE PERIOD WILL HELP FORCE A WEAK
FRONTAL BOUNDARY SOUTH INTO THE AREA BY LATER TUESDAY-WEDNESDAY.
MOIST/UNSTABLE ENVIRONMENT ALONG/SOUTH OF BOUNDARY SUPPORT GOING
CHANCE POPS FOR CONVECTION...ALTHOUGH FORCING MAY NOT BE STRONG
ENOUGH ON TUESDAY TO OVERCOME CAPPING INVERSION WITH THE LOCAL AREA
DISPLACED SOUTH OF STRONGER/MORE PERTURBED WESTERLY FLOW. IF/WHERE
CONVECTION FIRES HEAVY RAIN WILL LIKELY BECOME THE PRIMARY CONCERN
GIVEN WEAK FLOW AND ~2" PWAT POOLING INVOF BOUNDARY.
00/12Z MODEL ITERATIONS OVERALL TRENDED TOWARD A DRIER SOLUTION
LATER WEDNESDAY INTO THURSDAY...ESPECIALLY ALONG/NORTH OF HWY
30...WITH MORE PRONOUNCED NORTHEAST CONUS UPPER TROUGHING ALLOWING A
LOW LEVEL ANTICYCLONE TO BUILD INTO THE GREAT LAKES REGION. THIS
WOULD HELP STALL THE EASTWARD PROGRESSION OF A ROCKIES SHORTWAVE AND
PUSH THE ACTIVE INSTABILITY GRADIENT SOUTH OF THE IWX CWA. GIVEN
THESE TRENDS OPTED TO LOWER POPS...WITH A COUPLE DAYS OF COOLER/LESS
HUMID WEATHER POSSIBLE. LITTLE TO NO CHANGE FRIDAY AND BEYOND AS
GUIDANCE CONTINUE TO STRUGGLE WITH TIMING/SPEED OF A LONGER
WAVELENGTH TROUGH MODELED TO PROPAGATE EAST THROUGH THE
MIDWEST/GREAT LAKES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 728 PM EDT SUN AUG 24 2014
A SUBTLE SHORT WAVE OVER A PERSISTENT AND SUBTLE SURFACE BOUNDARY
ALONG WITH WEAK THETA E ADVECTION WAS LEADING TO ISOLATED SHOWERS
BETWEEN KSBN AND KFWA EARLY THIS EVENING. RUC SOUNDINGS INDICATE A
CAP IN PLACE ABOVE 800MB AND THIS HAS SEEMED TO LIMIT DEVELOPMENT
ALONG WITH MID LEVEL RIDGE. THIS WEAK ACTIVITY LOOKS TO REMAIN
EAST OF KSBN AND JUST NORTH OF KFWA SO WILL BEGIN THE PERIOD
QUIET WITH VFR CONDITIONS. MOIST BOUNDARY LAYER AND WINDS UNDER 5
KNOTS OVERNIGHT MAY ALLOW FOR PATCHY BR AND STRATUS SO KEPT A
TEMPO GROUP GOING FOR THIS. UPSTREAM CONVECTION NOW DEVELOPING
OVER MN TO IA EXPECTED TO GROW OVERNIGHT. COMPOSITE OUTFLOW AND/OR
MCV INDICATED BY SOME MODELS OF MAKING A RUN TOWARD OUR AREA
MONDAY MORNING BUT IN A WEAKENED STATE. WILL KEEP THIS OUT OF
POINT TAFS AT THIS TIME GIVEN SMALL CHANCES AND PROBLEMS MODELING
CONVECTION.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...STEINWEDEL
AVIATION...LASHLEY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
216 PM EDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 401 AM EDT SAT AUG 23 2014
WARM AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY BEFORE A
BRIEF BREAK IN THE STICKY CONDITIONS ARRIVES TONIGHT INTO SUNDAY
AS HIGH PRESSURE BUILDS IN FROM THE NORTHEAST. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON AND EVENING WITH
CHANCES DIMINISHING TONIGHT. DRY CONDITIONS ARE EXPECTED UNTIL
TUESDAY WHEN A COLD FRONT BEGINS TO APPROACH THE AREA. HIGHS WILL
BE IN THE 80S WITH LOWS IN THE 60S THE NEXT COUPLE OF DAYS.
&&
.UPDATE...
ISSUED AT 1116 AM EDT SAT AUG 23 2014
FOG HAS DISSIPATED ACROSS MOST OF THE AREA THIS MORNING...WITH THE
EXCEPTION BEING JUST SOME PATCHY 2-5 MILE VISIBILITIES WHERE
STRATUS DECK HAS PERSISTED THE LONGEST FROM SOUTHWEST LOWER
MICHIGAN SOUTHEASTWARD TO LIMA OHIO. MCS ACROSS EASTERN
IOWA/NORTHWEST ILLINOIS WILL BE THE NEXT ITEM OF CONCERN TO
ADDRESS FOR THE LOCAL AREA. CORFIDI VECTORS SUPPORT MORE OF AN
EAST/SOUTH PROPAGATION THIS AFTERNOON...WITH ORIENTATION OF
STRONGEST INSTABILITY AXIS ALSO FAVORING GENERAL
PROPAGATION/DEVELOPMENT TO THE SOUTHEAST...CLIPPING ESPECIALLY
SOUTHWEST PORTIONS OF THE AREA. HAVE INCREASED TO MID RANGE CHANCE
POPS ACROSS THE FAR SOUTHWEST TO ACCOUNT FOR THIS...WHILE
MAINTAINING OVERALL SOUTHWEST TO NORTHEAST POP GRADIENT FROM
PREVIOUS FORECAST. SEVERE WEATHER POTENTIAL STILL APPEARS TO BE
QUITE LOW WITH ANY LOW END/ISOLD RISK LIKELY BEING CONFINED TO RICHER
LOW LEVEL MOISTURE AXIS ACROSS SOUTHWEST PORTIONS OF THE AREA.
WHILE INSTABILITY WILL BE MAXIMIZED ACROSS THE SOUTHWEST...THIS
MAY REPRESENT A MINIMUM IN DEEP LAYER SHEAR. ONLY CAVEAT TO THIS
WOULD BE FOR SMALLER SCALE AREA OF LOCALLY ENHANCED SHEAR
ASSOCIATED WITH CONVECTIVELY ENHANCED VORT MAX EMANATING FROM
IOWA/ILLINOIS CONVECTION. GIVEN HEAVY RAINFALL OVER PAST FEW DAYS
ACROSS THE SOUTHWEST...WILL ESPECIALLY HAVE TO MONITOR FOR ANY
STORMS CAPABLE OF LOCALIZED HEAVIER RAINFALL. TEMPS APPEAR TO BE
IN GOOD SHAPE WITH JUST SOME MINOR TWEAKS TO MORNING DIURNAL CURVE
TO ACCOUNT FOR LINGERING STRATUS DECK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EDT SAT AUG 23 2014
SEVERAL SMALLER ITEMS TO TRY TO SORT OUT FOR THE FORECAST. FIRST OFF
WILL BE COMBINATION OF MOIST LOW LEVEL AIR MASS AND MOSTLY CLEAR
SKIES ALLOWING FOR STRATUS/FOG DEVELOPMENT ACROSS THE AREA.
OBSERVATIONS HAVE BEEN SHOWING THIS ALREADY TAKING PLACE...WITH
ISSUES EXPECTED TO PERSIST THROUGH AT LEAST 10 AM BEFORE SUFFICIENT
MIXING OCCURS TO HELP BREAK THINGS UP.
NEXT UP WILL BE ATTEMPT TO ADVECT IN SOMEWHAT DRIER AIR FROM THE NE
AGAINST THE PERSISTENT BUT WEAK SW FLOW ACROSS MUCH OF THE WESTERN
GREAT LAKES. A SUBTLE BOUNDARY WAS LOCATED FROM S LK MICHIGAN TO
VICINITY OF FT WAYNE. THIS FEATURE...COMBINED WITH WHAT APPEARS TO
BE A MID LEVEL DISTURBANCE OR SERIES OF GRAVITY WAVES...HELPED SPARK
SMALL AREAS OF SLOW MOVING SHOWERS AND STORMS THAT HAVE SINCE
DISSIPATED. LOCATIONS ALONG AND SW OF THIS BOUNDARY WILL SEE A
CHANCE FOR HIT OR MISS SHOWERS/STORMS THIS AFTERNOON/EVE IF
SUFFICIENT HEATING CAN TAKE PLACE. WARM AND HUMID CONDITIONS WILL
REMAIN UNTIL THE NE FLOW CAN STRENGTHEN SLIGHTLY AS RIDGE INFLUENCE
BRIEFLY RELAXES WITH DEWPOINTS DROPPING INTO THE MID 60S (LOW 60S
NE). A FEW RUNS OF THE RUC TRY TO BRING THIS DRIER AIR A BIT FASTER
IN NE SECTIONS THAT CURRENTLY DEPICTED. GIVEN WEAK NATURE OF
SLOW...THINK SLOWER IS BETTER AT THIS POINT UNTIL DEGREE OF MIXING
CAN BE DETERMINED. AS A RESULT...HIGHS SHOULD REACH THE MID 80S WITH
HEAT INDICES NEAR OR JUST INTO THE 90S.
NE FLOW WILL PUSH AXIS OF BEST PRECIPITATION POTENTIAL TO THE SW OF
THE REGION DURING THE EVENING HOURS...LEADING TO WHAT SHOULD BE A
PLEASANTLY DRY NIGHT AS LOWS DROP INTO THE MID 60S TO NEAR 70. HAVE
KEPT A LINGERING SLGT CHC OF SHOWERS IN FAR SW AREAS EARLY EVENING
BUT THEN REMOVED ALL MENTION OF PRECIPITATION AFTER 3Z.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 401 AM EDT SAT AUG 23 2014
STRONG SHRTWV MOVG THROUGH NRN NEVADA THIS MORNING EXPECTED TO LIFT
SLOWLY NE THROUGH THE NRN HIGH PLAINS SUNDAY WITH DOWNSTREAM RIDGE
MOVG EAST ACROSS OUR CWA. LACK OF FORCING AND A LITTLE DRIER AIR
ADVECTING INTO OUR AREA IN THE H925-H85 LAYER DUE TO EASTERLY FLOW
AROUND STRENGTHENING ANTICYCLONE OVER THE LWR GRTLKS SUGGESTS DRY
CONDITIONS ACROSS OUR AREA. GOOD DEAL OF SUNSHINE SHOULD ALLOW
MIXING UP TO NEAR H850 WHICH WOULD RESULT IN HIGHS IN THE M-U80S.
NRN PLAINS SHRTWV EXPECTED TO MOVE EAST TO ONTARIO ON MONDAY. RIDGE
OVER THE UPR GRTLKS WILL FLATTEN OUT IN RESPONSE BUT SHOULD HOLD
STRONG IN OUR AREA KEEPING CONDITIONS DRY. TEMPS EXPECTED TO
CONTINUE SLOW WARMING TREND AS WINDS VEER MORE SOUTHERLY WITH HIGHS
IN THE U80S/L90S.
ONTARIO SHRTWV EXPECTED TO SHEAR OUT AND LIFT ENE INTO QUEBEC TUE
WITH TRAILING CDFNT SINKING SLOWLY SOUTH INTO OR CLOSE TO NRN
PORTION OF OUR CWA BY WED MORNING. TSTMS SHOULD DEVELOP ALONG THE
FRONT AND MAY PROPAGATE SE INTO UNSTABLE AIRMASS OVER OUR AREA...
BUT CAPPING INVERSION MAKES THIS SCENARIO DOUBTFUL... SO JUST CONTD
WITH LOW CHC POPS. TEMPS SHOULD REMAIN WELL ABOVE NORMAL WITH HIGHS
AROUND 90 AND LOWS NEAR 70.
MODEL SOLUTIONS DIVERGE SIGNIFICANTLY LATE WEEK WITH ECMWF/GEM
SUGGESTING NEXT STRONG SHRTWV TO MOVE INTO MEAN WRN TROF WILL
CUT-OFF OVER THE ROCKIES AND THEN MOVE SLOWLY EAST... WHILE GFS
SUGGESTS A MORE PROGRESSIVE SCENARIO. IN EITHER CASE... LOW POPS
STILL WARRANTED FOR WED-THU... WHILE GFS INDICATES COOLER/DRIER
CONDITIONS WILL OVERSPREAD THE AREA BY FRIDAY. THIS SOLUTION IN
BETTER AGREEMENT WITH GOING FCST AND GIVEN EXCESSIVE UNCERTAINTY
WITH LARGE MODEL DIFFERENCES... STAYED CLOSE TO PREVIOUS FCST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 152 PM EDT SAT AUG 23 2014
CONVECTIVE COMPLEX ACROSS NORTHERN ILLINOIS HAS EXHIBITED SOME
TREND TO SOUTHEAST PROPAGATION OVER THE LAST HOUR AND EXPECTING
THIS OVERALL TREND TO PERSIST THROUGH THE REMAINDER OF THE
AFTERNOON. WILL HAVE TO MONITOR FOR OUTFLOW ACCELERATING AHEAD OF
THIS LINE TO POSSIBLY BE FOCUS FOR ADDITIONAL THUNDERSTORM
DEVELOPMENT AT KSBN LATE THIS AFTERNOON. IN THE MEANTIME...WILL
ALSO NEED TO MONITOR FOR POTENTIAL ISOLATED DEVELOPMENT ALONG
WEAK LAKE BREEZE WHICH HAS FORMED...WITH CU BEING MORE VERTICALLY
DEVELOPED RECENTLY TOWARD KMGC-KVPZ. SOME POTENTIAL OF THUNDER
WILL EXIST AT KSBN INTO THE EVENING HOURS AS REMNANT VORT MAX FROM
ILLINOIS CONVECTION DROPS SOUTHEAST THROUGH WESTERN INDIANA. WITH
BEST NEAR TERM POTENTIAL OF STORMS SOUTH AND WEST OF
TERMINALS...WILL HOLD OFF ON INCLUSION WTIH THE 18Z TAFS. SETUP
DOES APPEAR FAVORABLE FOR FOG AND STRATUS TO REDEVELOP
OVERNIGHT...AND HAVE CONTINUED TREND OF PREVIOUS ISSUANCE TO
IFR/LOWER END MVFR CONDITIONS OVERNIGHT. SLIGHTLY DRIER AIR TO
ADVECT EASTWARD ON SUNDAY AND MID LEVEL RIDGE BUILDING INTO THE
AREA SHOULD TEND TO DISCOURAGE THUNDER CHANCES FOR SUNDAY...WITH
EAST WINDS OF 10 KNOTS OR LESS CONTINUING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MARSILI
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1134 AM EDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 401 AM EDT SAT AUG 23 2014
WARM AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY BEFORE A
BRIEF BREAK IN THE STICKY CONDITIONS ARRIVES TONIGHT INTO SUNDAY
AS HIGH PRESSURE BUILDS IN FROM THE NORTHEAST. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON AND EVENING WITH
CHANCES DIMINISHING TONIGHT. DRY CONDITIONS ARE EXPECTED UNTIL
TUESDAY WHEN A COLD FRONT BEGINS TO APPROACH THE AREA. HIGHS WILL
BE IN THE 80S WITH LOWS IN THE 60S THE NEXT COUPLE OF DAYS.
&&
.UPDATE...
ISSUED AT 1116 AM EDT SAT AUG 23 2014
FOG HAS DISSIPATED ACROSS MOST OF THE AREA THIS MORNING...WITH THE
EXCEPTION BEING JUST SOME PATCHY 2-5 MILE VISIBILITIES WHERE
STRATUS DECK HAS PERSISTED THE LONGEST FROM SOUTHWEST LOWER
MICHIGAN SOUTHEASTWARD TO LIMA OHIO. MCS ACROSS EASTERN
IOWA/NORTHWEST ILLINOIS WILL BE THE NEXT ITEM OF CONCERN TO
ADDRESS FOR THE LOCAL AREA. CORFIDI VECTORS SUPPORT MORE OF AN
EAST/SOUTH PROPAGATION THIS AFTERNOON...WITH ORIENTATION OF
STRONGEST INSTABILITY AXIS ALSO FAVORING GENERAL
PROPAGATION/DEVELOPMENT TO THE SOUTHEAST...CLIPPING ESPECIALLY
SOUTHWEST PORTIONS OF THE AREA. HAVE INCREASED TO MID RANGE CHANCE
POPS ACROSS THE FAR SOUTHWEST TO ACCOUNT FOR THIS...WHILE
MAINTAINING OVERALL SOUTHWEST TO NORTHEAST POP GRADIENT FROM
PREVIOUS FORECAST. SEVERE WEATHER POTENTIAL STILL APPEARS TO BE
QUITE LOW WITH ANY LOW END/ISOLD RISK LIKELY BEING FINED TO RICHER
LOW LEVEL MOISTURE AXIS ACROSS SOUTHWEST PORTIONS OF THE AREA.
WHILE INSTABILITY WILL BE MAXIMIZED ACROSS THE SOUTHWEST...THIS
MAY REPRESENT A MINIMUM IN DEEP LAYER SHEAR. ONLY CAVEAT TO THIS
WOULD BE FOR SMALLER SCALE AREA OF LOCALLY ENHANCED SHEAR
ASSOCIATED WITH CONVECTIVELY ENHANCED VORT MAX EMANATING FROM
IOWA/ILLINOIS CONVECTION. GIVEN HEAVY RAINFALL OVER PAST FEW DAYS
ACROSS THE SOUTHWEST...WILL ESPECIALLY HAVE TO MONITOR FOR ANY
STORMS CAPABLE OF LOCALIZED HEAVIER RAINFALL. TEMPS APPEAR TO BE
IN GOOD SHAPE WITH JUST SOME MINOR TWEAKS TO MORNING DIURNAL CURVE
TO ACCOUNT FOR LINGERING STRATUS DECK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EDT SAT AUG 23 2014
SEVERAL SMALLER ITEMS TO TRY TO SORT OUT FOR THE FORECAST. FIRST OFF
WILL BE COMBINATION OF MOIST LOW LEVEL AIR MASS AND MOSTLY CLEAR
SKIES ALLOWING FOR STRATUS/FOG DEVELOPMENT ACROSS THE AREA.
OBSERVATIONS HAVE BEEN SHOWING THIS ALREADY TAKING PLACE...WITH
ISSUES EXPECTED TO PERSIST THROUGH AT LEAST 10 AM BEFORE SUFFICIENT
MIXING OCCURS TO HELP BREAK THINGS UP.
NEXT UP WILL BE ATTEMPT TO ADVECT IN SOMEWHAT DRIER AIR FROM THE NE
AGAINST THE PERSISTENT BUT WEAK SW FLOW ACROSS MUCH OF THE WESTERN
GREAT LAKES. A SUBTLE BOUNDARY WAS LOCATED FROM S LK MICHIGAN TO
VICINITY OF FT WAYNE. THIS FEATURE...COMBINED WITH WHAT APPEARS TO
BE A MID LEVEL DISTURBANCE OR SERIES OF GRAVITY WAVES...HELPED SPARK
SMALL AREAS OF SLOW MOVING SHOWERS AND STORMS THAT HAVE SINCE
DISSIPATED. LOCATIONS ALONG AND SW OF THIS BOUNDARY WILL SEE A
CHANCE FOR HIT OR MISS SHOWERS/STORMS THIS AFTERNOON/EVE IF
SUFFICIENT HEATING CAN TAKE PLACE. WARM AND HUMID CONDITIONS WILL
REMAIN UNTIL THE NE FLOW CAN STRENGTHEN SLIGHTLY AS RIDGE INFLUENCE
BRIEFLY RELAXES WITH DEWPOINTS DROPPING INTO THE MID 60S (LOW 60S
NE). A FEW RUNS OF THE RUC TRY TO BRING THIS DRIER AIR A BIT FASTER
IN NE SECTIONS THAT CURRENTLY DEPICTED. GIVEN WEAK NATURE OF
SLOW...THINK SLOWER IS BETTER AT THIS POINT UNTIL DEGREE OF MIXING
CAN BE DETERMINED. AS A RESULT...HIGHS SHOULD REACH THE MID 80S WITH
HEAT INDICES NEAR OR JUST INTO THE 90S.
NE FLOW WILL PUSH AXIS OF BEST PRECIPITATION POTENTIAL TO THE SW OF
THE REGION DURING THE EVENING HOURS...LEADING TO WHAT SHOULD BE A
PLEASANTLY DRY NIGHT AS LOWS DROP INTO THE MID 60S TO NEAR 70. HAVE
KEPT A LINGERING SLGT CHC OF SHOWERS IN FAR SW AREAS EARLY EVENING
BUT THEN REMOVED ALL MENTION OF PRECIPITATION AFTER 3Z.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 401 AM EDT SAT AUG 23 2014
STRONG SHRTWV MOVG THROUGH NRN NEVADA THIS MORNING EXPECTED TO LIFT
SLOWLY NE THROUGH THE NRN HIGH PLAINS SUNDAY WITH DOWNSTREAM RIDGE
MOVG EAST ACROSS OUR CWA. LACK OF FORCING AND A LITTLE DRIER AIR
ADVECTING INTO OUR AREA IN THE H925-H85 LAYER DUE TO EASTERLY FLOW
AROUND STRENGTHENING ANTICYCLONE OVER THE LWR GRTLKS SUGGESTS DRY
CONDITIONS ACROSS OUR AREA. GOOD DEAL OF SUNSHINE SHOULD ALLOW
MIXING UP TO NEAR H850 WHICH WOULD RESULT IN HIGHS IN THE M-U80S.
NRN PLAINS SHRTWV EXPECTED TO MOVE EAST TO ONTARIO ON MONDAY. RIDGE
OVER THE UPR GRTLKS WILL FLATTEN OUT IN RESPONSE BUT SHOULD HOLD
STRONG IN OUR AREA KEEPING CONDITIONS DRY. TEMPS EXPECTED TO
CONTINUE SLOW WARMING TREND AS WINDS VEER MORE SOUTHERLY WITH HIGHS
IN THE U80S/L90S.
ONTARIO SHRTWV EXPECTED TO SHEAR OUT AND LIFT ENE INTO QUEBEC TUE
WITH TRAILING CDFNT SINKING SLOWLY SOUTH INTO OR CLOSE TO NRN
PORTION OF OUR CWA BY WED MORNING. TSTMS SHOULD DEVELOP ALONG THE
FRONT AND MAY PROPAGATE SE INTO UNSTABLE AIRMASS OVER OUR AREA...
BUT CAPPING INVERSION MAKES THIS SCENARIO DOUBTFUL... SO JUST CONTD
WITH LOW CHC POPS. TEMPS SHOULD REMAIN WELL ABOVE NORMAL WITH HIGHS
AROUND 90 AND LOWS NEAR 70.
MODEL SOLUTIONS DIVERGE SIGNIFICANTLY LATE WEEK WITH ECMWF/GEM
SUGGESTING NEXT STRONG SHRTWV TO MOVE INTO MEAN WRN TROF WILL
CUT-OFF OVER THE ROCKIES AND THEN MOVE SLOWLY EAST... WHILE GFS
SUGGESTS A MORE PROGRESSIVE SCENARIO. IN EITHER CASE... LOW POPS
STILL WARRANTED FOR WED-THU... WHILE GFS INDICATES COOLER/DRIER
CONDITIONS WILL OVERSPREAD THE AREA BY FRIDAY. THIS SOLUTION IN
BETTER AGREEMENT WITH GOING FCST AND GIVEN EXCESSIVE UNCERTAINTY
WITH LARGE MODEL DIFFERENCES... STAYED CLOSE TO PREVIOUS FCST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 648 AM EDT SAT AUG 23 2014
FOG CAUSING WIDESPREAD LIFR CONDITIONS ACROSS NRN INDIANA EARLY THIS
MORNING. DIURNAL HEATING SHOULD ALLOW CONDITIONS TO GRDLY
IMPROVE TO VFR BY THIS AFTN. STNRY FRONT REMAINS DRAPED ACROSS THE
AREA AND MAY PROVIDE A FOCUS FOR TSRA THIS AFTN... HWVR CHANCES
TOO LOW TO MENTION IN THE TAFS. DRIER AIR EXPECTED TO MOVE INTO
THE AREA FROM THE EAST TONIGHT... BUT STILL SHOULD BE SUFFICIENT
RADIATIONAL COOLING FOR SOME MVFR VSBYS IN BR TOWARD DAYBREAK.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MARSILI
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...JT
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
655 AM EDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 401 AM EDT SAT AUG 23 2014
WARM AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY BEFORE A
BRIEF BREAK IN THE STICKY CONDITIONS ARRIVES TONIGHT INTO SUNDAY
AS HIGH PRESSURE BUILDS IN FROM THE NORTHEAST. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON AND EVENING WITH
CHANCES DIMINISHING TONIGHT. DRY CONDITIONS ARE EXPECTED UNTIL
TUESDAY WHEN A COLD FRONT BEGINS TO APPROACH THE AREA. HIGHS WILL
BE IN THE 80S WITH LOWS IN THE 60S THE NEXT COUPLE OF DAYS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EDT SAT AUG 23 2014
SEVERAL SMALLER ITEMS TO TRY TO SORT OUT FOR THE FORECAST. FIRST OFF
WILL BE COMBINATION OF MOIST LOW LEVEL AIR MASS AND MOSTLY CLEAR
SKIES ALLOWING FOR STRATUS/FOG DEVELOPMENT ACROSS THE AREA.
OBSERVATIONS HAVE BEEN SHOWING THIS ALREADY TAKING PLACE...WITH
ISSUES EXPECTED TO PERSIST THROUGH AT LEAST 10 AM BEFORE SUFFICIENT
MIXING OCCURS TO HELP BREAK THINGS UP.
NEXT UP WILL BE ATTEMPT TO ADVECT IN SOMEWHAT DRIER AIR FROM THE NE
AGAINST THE PERSISTENT BUT WEAK SW FLOW ACROSS MUCH OF THE WESTERN
GREAT LAKES. A SUBTLE BOUNDARY WAS LOCATED FROM S LK MICHIGAN TO
VICINITY OF FT WAYNE. THIS FEATURE...COMBINED WITH WHAT APPEARS TO
BE A MID LEVEL DISTURBANCE OR SERIES OF GRAVITY WAVES...HELPED SPARK
SMALL AREAS OF SLOW MOVING SHOWERS AND STORMS THAT HAVE SINCE
DISSIPATED. LOCATIONS ALONG AND SW OF THIS BOUNDARY WILL SEE A
CHANCE FOR HIT OR MISS SHOWERS/STORMS THIS AFTERNOON/EVE IF
SUFFICIENT HEATING CAN TAKE PLACE. WARM AND HUMID CONDITIONS WILL
REMAIN UNTIL THE NE FLOW CAN STRENGTHEN SLIGHTLY AS RIDGE INFLUENCE
BRIEFLY RELAXES WITH DEWPOINTS DROPPING INTO THE MID 60S (LOW 60S
NE). A FEW RUNS OF THE RUC TRY TO BRING THIS DRIER AIR A BIT FASTER
IN NE SECTIONS THAT CURRENTLY DEPICTED. GIVEN WEAK NATURE OF
SLOW...THINK SLOWER IS BETTER AT THIS POINT UNTIL DEGREE OF MIXING
CAN BE DETERMINED. AS A RESULT...HIGHS SHOULD REACH THE MID 80S WITH
HEAT INDICES NEAR OR JUST INTO THE 90S.
NE FLOW WILL PUSH AXIS OF BEST PRECIPITATION POTENTIAL TO THE SW OF
THE REGION DURING THE EVENING HOURS...LEADING TO WHAT SHOULD BE A
PLEASANTLY DRY NIGHT AS LOWS DROP INTO THE MID 60S TO NEAR 70. HAVE
KEPT A LINGERING SLGT CHC OF SHOWERS IN FAR SW AREAS EARLY EVENING
BUT THEN REMOVED ALL MENTION OF PRECIPITATION AFTER 3Z.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 401 AM EDT SAT AUG 23 2014
STRONG SHRTWV MOVG THROUGH NRN NEVADA THIS MORNING EXPECTED TO LIFT
SLOWLY NE THROUGH THE NRN HIGH PLAINS SUNDAY WITH DOWNSTREAM RIDGE
MOVG EAST ACROSS OUR CWA. LACK OF FORCING AND A LITTLE DRIER AIR
ADVECTING INTO OUR AREA IN THE H925-H85 LAYER DUE TO EASTERLY FLOW
AROUND STRENGTHENING ANTICYCLONE OVER THE LWR GRTLKS SUGGESTS DRY
CONDITIONS ACROSS OUR AREA. GOOD DEAL OF SUNSHINE SHOULD ALLOW
MIXING UP TO NEAR H850 WHICH WOULD RESULT IN HIGHS IN THE M-U80S.
NRN PLAINS SHRTWV EXPECTED TO MOVE EAST TO ONTARIO ON MONDAY. RIDGE
OVER THE UPR GRTLKS WILL FLATTEN OUT IN RESPONSE BUT SHOULD HOLD
STRONG IN OUR AREA KEEPING CONDITIONS DRY. TEMPS EXPECTED TO
CONTINUE SLOW WARMING TREND AS WINDS VEER MORE SOUTHERLY WITH HIGHS
IN THE U80S/L90S.
ONTARIO SHRTWV EXPECTED TO SHEAR OUT AND LIFT ENE INTO QUEBEC TUE
WITH TRAILING CDFNT SINKING SLOWLY SOUTH INTO OR CLOSE TO NRN
PORTION OF OUR CWA BY WED MORNING. TSTMS SHOULD DEVELOP ALONG THE
FRONT AND MAY PROPAGATE SE INTO UNSTABLE AIRMASS OVER OUR AREA...
BUT CAPPING INVERSION MAKES THIS SCENARIO DOUBTFUL... SO JUST CONTD
WITH LOW CHC POPS. TEMPS SHOULD REMAIN WELL ABOVE NORMAL WITH HIGHS
AROUND 90 AND LOWS NEAR 70.
MODEL SOLUTIONS DIVERGE SIGNIFICANTLY LATE WEEK WITH ECMWF/GEM
SUGGESTING NEXT STRONG SHRTWV TO MOVE INTO MEAN WRN TROF WILL
CUT-OFF OVER THE ROCKIES AND THEN MOVE SLOWLY EAST... WHILE GFS
SUGGESTS A MORE PROGRESSIVE SCENARIO. IN EITHER CASE... LOW POPS
STILL WARRANTED FOR WED-THU... WHILE GFS INDICATES COOLER/DRIER
CONDITIONS WILL OVERSPREAD THE AREA BY FRIDAY. THIS SOLUTION IN
BETTER AGREEMENT WITH GOING FCST AND GIVEN EXCESSIVE UNCERTAINTY
WITH LARGE MODEL DIFFERENCES... STAYED CLOSE TO PREVIOUS FCST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 648 AM EDT SAT AUG 23 2014
FOG CAUSING WIDESPREAD LIFR CONDITIONS ACROSS NRN INDIANA EARLY THIS
MORNING. DIURNAL HEATING SHOULD ALLOW CONDITIONS TO GRDLY
IMPROVE TO VFR BY THIS AFTN. STNRY FRONT REMAINS DRAPED ACROSS THE
AREA AND MAY PROVIDE A FOCUS FOR TSRA THIS AFTN... HWVR CHANCES
TOO LOW TO MENTION IN THE TAFS. DRIER AIR EXPECTED TO MOVE INTO
THE AREA FROM THE EAST TONIGHT... BUT STILL SHOULD BE SUFFICIENT
RADIATIONAL COOLING FOR SOME MVFR VSBYS IN BR TOWARD DAYBREAK.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...JT
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
426 AM EDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 401 AM EDT SAT AUG 23 2014
WARM AND HUMID CONDITIONS WILL PERSIST FOR ONE MORE DAY BEFORE A
BRIEF BREAK IN THE STICKY CONDITIONS ARRIVES TONIGHT INTO SUNDAY
AS HIGH PRESSURE BUILDS IN FROM THE NORTHEAST. SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON AND EVENING WITH
CHANCES DIMINISHING TONIGHT. DRY CONDITIONS ARE EXPECTED UNTIL
TUESDAY WHEN A COLD FRONT BEGINS TO APPROACH THE AREA. HIGHS WILL
BE IN THE 80S WITH LOWS IN THE 60S THE NEXT COUPLE OF DAYS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EDT SAT AUG 23 2014
SEVERAL SMALLER ITEMS TO TRY TO SORT OUT FOR THE FORECAST. FIRST OFF
WILL BE COMBINATION OF MOIST LOW LEVEL AIR MASS AND MOSTLY CLEAR
SKIES ALLOWING FOR STRATUS/FOG DEVELOPMENT ACROSS THE AREA.
OBSERVATIONS HAVE BEEN SHOWING THIS ALREADY TAKING PLACE...WITH
ISSUES EXPECTED TO PERSIST THROUGH AT LEAST 10 AM BEFORE SUFFICIENT
MIXING OCCURS TO HELP BREAK THINGS UP.
NEXT UP WILL BE ATTEMPT TO ADVECT IN SOMEWHAT DRIER AIR FROM THE NE
AGAINST THE PERSISTENT BUT WEAK SW FLOW ACROSS MUCH OF THE WESTERN
GREAT LAKES. A SUBTLE BOUNDARY WAS LOCATED FROM S LK MICHIGAN TO
VICINITY OF FT WAYNE. THIS FEATURE...COMBINED WITH WHAT APPEARS TO
BE A MID LEVEL DISTURBANCE OR SERIES OF GRAVITY WAVES...HELPED SPARK
SMALL AREAS OF SLOW MOVING SHOWERS AND STORMS THAT HAVE SINCE
DISSIPATED. LOCATIONS ALONG AND SW OF THIS BOUNDARY WILL SEE A
CHANCE FOR HIT OR MISS SHOWERS/STORMS THIS AFTERNOON/EVE IF
SUFFICIENT HEATING CAN TAKE PLACE. WARM AND HUMID CONDITIONS WILL
REMAIN UNTIL THE NE FLOW CAN STRENGTHEN SLIGHTLY AS RIDGE INFLUENCE
BRIEFLY RELAXES WITH DEWPOINTS DROPPING INTO THE MID 60S (LOW 60S
NE). A FEW RUNS OF THE RUC TRY TO BRING THIS DRIER AIR A BIT FASTER
IN NE SECTIONS THAT CURRENTLY DEPICTED. GIVEN WEAK NATURE OF
SLOW...THINK SLOWER IS BETTER AT THIS POINT UNTIL DEGREE OF MIXING
CAN BE DETERMINED. AS A RESULT...HIGHS SHOULD REACH THE MID 80S WITH
HEAT INDICES NEAR OR JUST INTO THE 90S.
NE FLOW WILL PUSH AXIS OF BEST PRECIPITATION POTENTIAL TO THE SW OF
THE REGION DURING THE EVENING HOURS...LEADING TO WHAT SHOULD BE A
PLEASANTLY DRY NIGHT AS LOWS DROP INTO THE MID 60S TO NEAR 70. HAVE
KEPT A LINGERING SLGT CHC OF SHOWERS IN FAR SW AREAS EARLY EVENING
BUT THEN REMOVED ALL MENTION OF PRECIPITATION AFTER 3Z.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 401 AM EDT SAT AUG 23 2014
STRONG SHRTWV MOVG THROUGH NRN NEVADA THIS MORNING EXPECTED TO LIFT
SLOWLY NE THROUGH THE NRN HIGH PLAINS SUNDAY WITH DOWNSTREAM RIDGE
MOVG EAST ACROSS OUR CWA. LACK OF FORCING AND A LITTLE DRIER AIR
ADVECTING INTO OUR AREA IN THE H925-H85 LAYER DUE TO EASTERLY FLOW
AROUND STRENGTHENING ANTICYCLONE OVER THE LWR GRTLKS SUGGESTS DRY
CONDITIONS ACROSS OUR AREA. GOOD DEAL OF SUNSHINE SHOULD ALLOW
MIXING UP TO NEAR H850 WHICH WOULD RESULT IN HIGHS IN THE M-U80S.
NRN PLAINS SHRTWV EXPECTED TO MOVE EAST TO ONTARIO ON MONDAY. RIDGE
OVER THE UPR GRTLKS WILL FLATTEN OUT IN RESPONSE BUT SHOULD HOLD
STRONG IN OUR AREA KEEPING CONDITIONS DRY. TEMPS EXPECTED TO
CONTINUE SLOW WARMING TREND AS WINDS VEER MORE SOUTHERLY WITH HIGHS
IN THE U80S/L90S.
ONTARIO SHRTWV EXPECTED TO SHEAR OUT AND LIFT ENE INTO QUEBEC TUE
WITH TRAILING CDFNT SINKING SLOWLY SOUTH INTO OR CLOSE TO NRN
PORTION OF OUR CWA BY WED MORNING. TSTMS SHOULD DEVELOP ALONG THE
FRONT AND MAY PROPAGATE SE INTO UNSTABLE AIRMASS OVER OUR AREA...
BUT CAPPING INVERSION MAKES THIS SCENARIO DOUBTFUL... SO JUST CONTD
WITH LOW CHC POPS. TEMPS SHOULD REMAIN WELL ABOVE NORMAL WITH HIGHS
AROUND 90 AND LOWS NEAR 70.
MODEL SOLUTIONS DIVERGE SIGNIFICANTLY LATE WEEK WITH ECMWF/GEM
SUGGESTING NEXT STRONG SHRTWV TO MOVE INTO MEAN WRN TROF WILL
CUT-OFF OVER THE ROCKIES AND THEN MOVE SLOWLY EAST... WHILE GFS
SUGGESTS A MORE PROGRESSIVE SCENARIO. IN EITHER CASE... LOW POPS
STILL WARRANTED FOR WED-THU... WHILE GFS INDICATES COOLER/DRIER
CONDITIONS WILL OVERSPREAD THE AREA BY FRIDAY. THIS SOLUTION IN
BETTER AGREEMENT WITH GOING FCST AND GIVEN EXCESSIVE UNCERTAINTY
WITH LARGE MODEL DIFFERENCES... STAYED CLOSE TO PREVIOUS FCST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1209 AM EDT SAT AUG 23 2014
STRATUS AND FOG WILL POSE A CONCERN INTO SATURDAY MORNING AT BOTH
SITES AS MOIST BOUNDARY LAYER REMAINS IN PLACE FROM RECENT
RAINFALL AND ABUNDANT MOISTURE IN THE AREA. A BOUNDARY WAS LOCATED
IN THE VICINITY OF BOTH SITES BUT WAS MOST ACTIVE IN AND AROUND
KFWA WHERE A SMALL AREA OF SHOWERS/STORMS WAS PERSISTING. THIS
SHOULD DRIFT SOUTHEAST OVER THE NEXT HALF HOUR TO HOUR WITH
ADDITIONAL ACTIVITY UPSTREAM THAT COULD DRIFT SE TOWARDS THE
AIRPORT AGAIN. WILL MONITOR FOR AMENDMENTS.
OTHERWISE NO SIGNIFICANT CHANGES PLANNED TO TAFS INTO SATURDAY
NIGHT AS OVERALL PATTERN WILL CHANGE LITTLE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...FISHER
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...FISHER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DES MOINES IA
416 AM CDT SAT AUG 23 2014
.SHORT TERM /TODAY/...
ISSUED AT 415 AM CDT SAT AUG 23 2014
YET ANOTHER ACTIVE OVERNIGHT/EARLY MORNING TODAY WITH A LARGE AREA
OF THUNDERSTORMS MOVING ACROSS WEST/SOUTHWEST IOWA AT THE CURRENT
HOUR. THIS ACTIVITY IS ASSOCIATED WITH THE NOSE OF THE NOCTURNAL LOW
LEVEL JET AND A SURGE OF WARM AIR ADVECTION ALOFT COMING OUT OF THE
SOUTHERN PLAINS. EXPECT THE STORMS TO MOVE SLOWLY ACROSS MUCH OF THE
FORECAST AREA THIS MORNING AND HAVE INCLUDED HIGH POPS ACCORDINGLY.
WHILE LOCALLY HEAVY RAINFALL WILL OCCUR...THE BAR FOR FLASH FLOODING
IS SET HIGH DUE TO ANTECEDENT AND VEGETATIVE CONDITIONS.
AS THE WARM AIR ADVECTION SURGE CONTINUES NORTHWARD AND THE JET
WEAKENS AFTER SUNRISE...EXPECT THE SWATH OF THUNDERSTORMS TO SHIFT
TOWARD THE NORTH AND NORTHEAST AND GRADUALLY DIMINISH...LIKELY
ENDING IN OUR NORTHEASTERN COUNTIES IN THE EARLY AFTERNOON.
MEANWHILE...BEHIND THIS PUSH HOTTER CONDITIONS WILL MOVE INTO
PARTICULARLY SOUTH/SOUTHWEST IOWA IN THE AFTERNOON. HEATING WILL BE
MITIGATED BY MORNING CONVECTIVE DEBRIS CLOUDS...SOUTHEASTERLY LOW
LEVEL WIND TRAJECTORIES...AND PERSISTENTLY HIGH DEWPOINTS...BUT
BELIEVE TEMPERATURES SHOULD STILL EXCEED YESTERDAYS LEVELS IN THESE
AREAS WITH LOWER 90S TYPICAL. HEAT INDEX VALUES WILL LIKELY TOP OUT
IN THE 100 TO 105 DEGREE RANGE ONCE AGAIN...JUST BELOW ADVISORY
CRITERIA AND PRECLUDING A HEADLINE ISSUANCE AT THIS TIME.
.LONG TERM /TONIGHT THROUGH FRIDAY/...
ISSUED AT 415 AM CDT SAT AUG 23 2014
UPPER LOW MOVING ACROSS IDAHO THIS MORNING...WILL CONTINUE TO
SHIFT EAST/NORTHEAST INTO WESTERN NORTH DAKOTA BY MID DAY SUNDAY.
STRONG PV ANOMALY OVER COLORADO AND NEW MEXICO WILL LIFT QUICKLY
NORTH AND BE INGESTED IN THE UPPER LOW OVERNIGHT. THIS WILL HELP
PUSH THE FRONTAL BOUNDARY WILL NORTH OF THE STATE AND PLACING THE
AREA INTO THE WARM SECTOR. MUCH DRIER MID LEVELS WILL HELP LOWER
PWATS DOWN TO NEAR 1.25 INCHES...WHICH WILL HELP STABILIZE THE
ATMOSPHERE. THE SUB TROPICAL HIGH WILL REMAIN ENTRENCHED OVER THE
SOUTHEAST CONUS AND WILL KEEP SOUTHWEST FLOW OVER THE STATE
THROUGH THE EARLY PORTION OF THE WEEK. TEMPERATURES SHOULD BE
QUITE WARM ON SUNDAY WITH THE THERMAL RIDGE IN PLACE WITH HIGHS
IN THE UPPER 80S TO MID 90S.
ANOTHER STRONG UPPER LOW WILL MOVE THROUGH THE INTERMOUNTAIN WEST
MID NEXT WEEK AND WILL HELP THE FRONTAL BOUNDARY DROP INTO IOWA
AND BECOME NEARLY STATIONARY ONCE AGAIN. THIS WILL RESULT INTO
SEVERAL CHANCES FOR THUNDERSTORMS TUESDAY AND WEDNESDAY WITH SOME
SEVERE WEATHER AND THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. THE
UPPER LEVEL SYSTEM WILL EVENTUALLY PUSH THE SFC BOUNDARY TO THE
EAST OF THE STATE THOUGH THIS MAY NOT OCCUR UNTIL THURSDAY. A
NEARLY 20 DEGREE DIFFERENCE IN TEMPERATURES NORTH AND SOUTH OF THE
BOUNDARY WHILE IT IS STALLED OVER THE AREA WITH 70S NORTH TO NEAR
90 SOUTH. COOLER FOR THE ENTIRE AREA BY FRIDAY.
&&
.AVIATION...23/06Z
ISSUED AT 1150 PM CDT FRI AUG 22 2014
DELAYED CONVECTION UNTIL PAST 12Z SATURDAY FOR ALL TAF SITES AS
THE 23/00Z HOPWRF AND HRRR ARE IN GOOD AGREEMENT WITH CONVECTION
SPREADING ACROSS SOUTH-CENTRAL IOWA WITH THE HRRR MORE WIDESPREAD
FURTHER NORTH. HAVE MENTION OF VCTS AT FOD/DSM/OTM WITH A LITTLE
HIGHER CONFIDENCE SITES WILL SEE STORMS. HAVE MVFR TO IFR VIS WRT
TO FOG PAST 08Z TONIGHT. MIXING DEVELOPS LATE SATURDAY MORNING AND
KEPT MENTION OF GUSTS THROUGH THE AFTERNOON HOURS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LEE
LONG TERM...DONAVON
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1150 PM CDT FRI AUG 22 2014
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
ISSUED AT 327 PM CDT FRI AUG 22 2014
THROUGH EARLY EVENING...STORMS HAVE FIRED IN TWO AREAS ACROSS
CENTRAL IOWA. THE NORTHERN MOST LINE OF STORMS IS ASSOCIATED WITH A
FRONTAL BOUNDARY THAT IS EVER SO SLOWLY MEANDERING SOUTH. FLOW IS
WEAK AND THERE IS LITTLE CONVERGENCE AND NO SHEAR TO SPEAK OF SO THE
STORMS WILL BECOME OUTFLOW DOMINANT AND SHOULD FALL APART BY 00-01Z.
FURTHER SOUTH STORMS HAVE FIRED ALONG A MOISTURE AXIS. THIS AXIS
WAS EVIDENT ON RADAR FOR MUCH OF THE DAY AND STORMS FIRED AFTER
SUFFICIENT HEATING DESTABILIZED THE ATMOSPHERE. THESE STORMS WILL
BE A BIT MORE ROBUST AND PRODUCE LOCALLY HEAVY RAINFALL...SOME
STRONGER WIND GUSTS AND POSSIBLY SOME SMALL HAIL. AGAIN...THESE
STORMS SHOULD MOVE EAST SOUTHEAST AND DIMINISH SHORTLY AFTER 00Z.
THE REST OF EARLY TO MID EVENING SHOULD BE RELATIVELY QUIET THOUGH
THINGS WILL FESTER THROUGH THE EVENING SO ISOLATED STORMS WILL STILL
BE POSSIBLE.
FOR THE REST OF TONIGHT...UPPER RIDGE OVER IOWA WILL GET PUSHED TO
THE EAST WITH THE AXIS BY 12Z SAT INTO WESTERN IL BY A DEEPENING
TROUGH OVER THE ROCKIES. SEVERAL WEAKER SHORTWAVES WILL EJECT OUT
OF THE BASE OF THE TROUGH PUSHING ACROSS NORTHERN/WESTERN IOWA. IN
ADDITION...THE FRONTAL BOUNDARY FROM A SURFACE LOW IN WESTERN KS
WILL LIFT NORTHWARD AS THE SURFACE LOW SHIFT TO THE NORTHEAST. TO
THE WEST OF IOWA THERE IS PRETTY IMPRESSIVE SHEAR AND STRONG THETA-E
ADVECTION THAT WILL WORK INTO THE WEST AND NORTH AND GRADUALLY SHIFT
MORE NORTH AND EAST. ONE AGAIN THE 4KM WRF HAD A DECENT HANDLE ON
ALL OF THE CONVECTION OF THIS AFTERNOON AND TONIGHT SO I DID PUT
SOME WEIGHT ON ITS SOLUTION FOR TONIGHT. STORMS SHOULD FIRE OUT
WEST OF IOWA THIS AFTERNOON AND EVENING AND WILL PROBABLY MERGE INTO
A CLUSTER OF STORMS THAT WILL THEN SHIFT INTO THE SOUTHWEST THIRD OF
SO OF IOWA DURING THE OVERNIGHT. THERE MAY BE ISOLATED STORMS
THROUGHOUT THE EVENING BUT THE MAIN PRECIP EVENT WILL OCCUR OVER THE
SOUTHWEST BETWEEN 08Z-12Z BEFORE LIFTING NORTH. SOME STORMS WILL
PRODUCE HEAVY RAINFALL BUT THERE MAY ALSO BE A COUPLE SEVERE STORMS
AS WELL...MAINLY OVER THE FAR WESTERN PORTION OF THE CWA. IT WILL
BE A MUGGY NIGHT WITH LOWS IN THE UPPER 60S OVER FAR NORTHERN IOWA
AND 70S ELSEWHERE. DEWPOINTS WILL STAY IN THE UPPER 60S AND LOW TO
MID 70S SO FOG WILL ONCE AGAIN DEVELOP...ESPECIALLY ACROSS THE
NORTH.
.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 327 PM CDT FRI AUG 22 2014
ACTIVE WX PATTERN EXPECTED AT LEAST THROUGH THE MIDDLE OF NEXT
WEEK...WITH HOT AND HUMID SUMMERTIME WEATHER GIVING WAY TO FALL-LIKE
WEATHER.
MID/UPPER-LEVEL WIND SPEED MAX PLUNGING SOUTHWARD ALONG THE PAC
COAST...ON THE WEST SIDE OF THE WESTERN U.S. TROF...WILL HELP
FACILIATE ITS INTENSIFICATION BEFORE IT LIFTS OUT. IN RESPONSE...THE
EASTERN U.S. RIDGE WILL AMPLIFY INTO THIS WEEKEND. A VORT MAX OVER
THE SW U.S. WILL CONTINUE LIFTING NORTHEASTWARD. BY THE BEGINNING OF
THE LONG TERM FCST PERIOD...LINGERING CONVECTION FROM OVERNIGHT WILL
CONTINUE LIFTING NORTHWARD AHEAD OF A NORTHWARD-ADVANCING FRONTAL
BOUNDARY. THE BOUNDARY IS EXPECTED TO BE IN THE VICINITY OF THE IA-
MN BORDER...LIKELY JUST NORTH OF IT...BY LATE AFTERNOON SATURDAY.
SOUTH OF THE BOUNDARY...TEMPERATURES WILL WARM MORE THAN WHAT WAS
SEEN TODAY. PREVIOUS FCST DISCUSSION ACKNOWLEDGED MIXING ISSUES OVER
THE PAST FEW DAYS AND ON SATURDAY...AND AGREE WITH THAT THINKING
HOWEVER EXPECT IT TO BE MORE THAN WAS SEEN TODAY AS EVIDENCED BY
STRONGER SURFACE WINDS THAN WAS SEEN TODAY. THUS HAVE NUDGED TEMPS
UP A DEGREE OR TWO FROM THE GOING FORECAST FOR SATURDAY AFTERNOON.
ADDITIONAL CONVECTION IS POSSIBLE SATURDAY NIGHT AS ANOTHER
MID/UPPER-LEVEL DISTURBANCE MOVES THROUGH THE CENTRAL/NORTHERN
PLAINS. BEST FORCING WILL REMAIN WEST AND NORTH OF THE CWA...AND
HAVE PAINTED POPS AS SUCH.
SUNDAY IS EXPECTED TO BE THE WARMEST DAY OF THE FCST PD WITH IA
SOLIDLY WITHIN THE WARM SECTOR. NAM HAS CONTINUED TREND FROM
PREVIOUS FCST OF BEING THE WARMEST WITH FCST HIGHS WELL INTO THE
90S. NAM IS SUGGESTING MORE MIXING ON SUNDAY THAN ON SATURDAY AS
EVIDENCED BY LOWER DEWPOINTS AND STRONGER SURFACE WINDS. FOR NOW
HAVE NOT CHANGED SUNDAY/S MAX TEMPS MUCH FROM PREVIOUS FCST. HEAT
INDEX VALUES WILL BE AS HIGH AS AROUND 100F.
HIGHER CHANCES OF SHRA/TSRA OCCUR SUNDAY NIGHT AS UPPER-LEVEL TROF
TO OUR WEST EJECTS NORTHEASTWARD AND PUSHES A BOUNDARY INTO IA.
MODELS SUGGEST THE BOUNDARY WILL HANG UP IN THE STATE...LIKELY
MAKING IT AS FAR SOUTHEAST AS CENTRAL IA. INSTABILITY AND FORCING
WILL BE PLENTIFUL ENOUGH TO RESULT IN AT LEAST SCATTERED SHRA/TSRA
DURING THE NIGHT. AS THE UPPER LEVEL TROF EJECTS...ADDITIONAL
UPSTREAM ENERGY WILL HELP ANOTHER TROF TO DEVELOP IN ITS PLACE OVER
THE NORTHERN U.S. ROCKIES.
WITH BOUNDARY REMAINING IN THE REGION...HAVE KEPT SLIGHT CHANCE POPS
GOING INTO MONDAY. AFTER THIS POINT...THE MODEL SOLUTIONS DIVERGE
LEADING TO INCREASING FORECAST UNCERTAINTY. GFS BRINGS THE SECOND
TROF THROUGH FASTER THAN THE EURO. EXPECT THE BOUNDARY TO MOVE
THROUGH THE CWA BY WEDNESDAY. HAVE INCREASED POPS BEGINNING TUESDAY
AND KEPT THEM IN PLACE THROUGH LATE IN THE DAY ON WEDNESDAY.
AFTER THE FRONTAL PASSAGE...A FEW DAYS OF FALL-LIKE WEATHER WILL
PREVAIL WITH HIGH TEMPS ACROSS THE NORTHERN CWA POSSIBLY NOT LEAVING
THE LOWER 70S ON WEDNESDAY.
&&
.AVIATION...23/06Z
ISSUED AT 1150 PM CDT FRI AUG 22 2014
DELAYED CONVECTION UNTIL PAST 12Z SATURDAY FOR ALL TAF SITES AS
THE 23/00Z HOPWRF AND HRRR ARE IN GOOD AGREEMENT WITH CONVECTION
SPREADING ACROSS SOUTH-CENTRAL IOWA WITH THE HRRR MORE WIDESPREAD
FURTHER NORTH. HAVE MENTION OF VCTS AT FOD/DSM/OTM WITH A LITTLE
HIGHER CONFIDENCE SITES WILL SEE STORMS. HAVE MVFR TO IFR VIS WRT
TO FOG PAST 08Z TONIGHT. MIXING DEVELOPS LATE SATURDAY MORNING AND
KEPT MENTION OF GUSTS THROUGH THE AFTERNOON HOURS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...FAB
LONG TERM...ZOGG
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
355 PM EDT SAT AUG 23 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 350 PM EDT SAT AUG 23 2014
19Z SFC ANALYSIS SHOWS OUR CONTINUING WEATHER CHALLENGE WITH THE LOW
PRESSURE OUT TO THE WEST AND HIGH PRESSURE TO THE SOUTH. A WAVY
NORTHWEST TO SOUTHEAST FRONT EXISTS JUST NORTH OF OUR AREA.
MEANWHILE...ALOFT...A RIDGE IS FOUND THROUGH THE LOWER MIDSECTION OF
THE NATION WITH A DIGGING TROUGH MOVING INTO THE MID ATLANTIC STATES.
THIS PLACES CENTRAL AND EASTERN KENTUCKY IN THE TRACK OF ENERGY
MOVING FROM THE UPPER MIDWEST INTO THE SOUTHERN APPALACHIANS TODAY.
THESE FEATURES HAVE BEEN COMBINING LATELY TO PRODUCE CLUSTERS OF
SHOWERS AND THUNDERSTORMS GENERALLY STARTING IN THE LATE AFTERNOON
AND LASTING INTO THE EVENING. THE HIGH PW AIR IN PLACE OVER THE
AREA...ALONG WITH THE DEWPOINTS PUSHING THE MID 70S...MAKES FOR
PROLIFIC RAIN PRODUCING CELLS. AS HAS BEEN THE CASE REMAINS SO
HEADING INTO LATE AFTERNOON...THOUGH THE AXIS OF CONCERN HAS SHIFTED
SLIGHTLY WEST OWING TO THE WIGGLE OF THE RIDGE IN RESPONSE TO THE
DIGGING TROUGH. CURRENTLY SCATTERED AND ISOLATED SHOWERS/STORMS ARE
DOTTING THE CUMBERLAND VALLEY WITH SIGNS OF LARGER CLUSTERS STARTING
TO TAKE SHAPE TO THE NORTHWEST. THOUGH DELAYED A BIT BY THE LOW
STRATUS DECK FOLLOWING THE DENSE FOG THIS MORNING...TEMPERATURES HAVE
CLIMBED SMARTLY INTO THE MIDDLE AND UPPER 80S THROUGH THE AREA AND
WITH SUCH HIGH DEWPOINTS ARE YIELDING HEAT INDICES IN THE 95 TO 100
DEGREE RANGE. WINDS HAVE BEEN MAINLY LIGHT AND VARIABLE THROUGH THE
AREA.
THE MODELS ARE ALL IN PRETTY GOOD AGREEMENT ALOFT WITH THE WIGGLE
WEST AND THEN BACK EAST OF THE UPPER RIDGE INTO MONDAY MORNING.
SHORTWAVE ENERGY MOVING SOUTH BETWEEN THE UPPER SYSTEMS WILL PASS
THROUGH CENTRAL AND EASTERN KENTUCKY TONIGHT WITH ONLY WEAKER PACKETS
FORESEEN THROUGH THE REST OF THE WEEKEND. GIVEN THE AGREEMENT OF THE
MODELS AND THE SMALLER SCALE NATURE OF CONVECTIVE ACTIVITY OF THIS
REGIME HAVE AGAIN FAVORED THE HRRR AND NAM12 THROUGH THE FIRST 18 TO
36 HOURS AND A MODEL CONSENSUS AFTER THAT INTO MONDAY MORNING.
SENSIBLE WEATHER WILL FEATURE ISOLATED AND SCATTERED CONVECTION
AROUND EAST KENTUCKY THROUGH THE NEXT SEVERAL HOURS WITH AN
DECENT POTENTIAL EVOLUTION OF STORMS INTO A LARGER SYSTEM LATER IN
THE FIRST PART OF THE EVENING SOMEWHERE TO THE NORTHWEST. THE
INGREDIENTS ARE THERE FOR ANOTHER ROUND OF SUCH STORMS AND THE
EXCESSIVE RAINFALL THEY PRODUCE. STILL THE BEST INDICATIONS ARE THAT
THE WORST OF ANY SUCH DEVELOPMENT WILL JUST BRUSH OUR SOUTHWESTERN
COUNTIES WHERE WE ARE NOT QUITE AS SATURATED AS THE EAST. THIS IS
GOOD NEWS...BUT GIVEN THE LOW FFG IN THE EAST JUST ABOUT ANY HEALTHY
STORM THERE WILL PROMPT FLASH FLOODING CONCERNS. WITH THE STILL HIGH
PWS AND INSTABILITY ACROSS THE ENTIRE AREA CANNOT CALL ANY PLACE FREE
OF LOCALIZED FLASH FLOOD CONCERNS. THE ACTIVITY IS EXPECTED TO DIE
DOWN LATER THIS EVENING AND WHEN COMBINED WITH AT LEAST PARTIAL
CLEARING WILL LIKELY BRING ABOUT ANOTHER BLANKET OF FOG BECOMING
DENSE IN AREAS TOWARD DAWN. WILL HIT THIS...IN ADDITION TO THE
STORM/FLOOD CONCERNS...HARD IN THE HWO. ONCE THE FOG BURNS OFF ON
SUNDAY...PARTLY SUNNY SKIES WILL AGAIN BUILD THE HEAT AND INSTABILITY
THROUGH THE AREA WHILE LOWER PWS FOR MUCH OF THE AREA WILL LIMIT TO A
SMALLER EXTENT FLASH FLOOD CONCERNS. EXPECT SOME COOLER AND...MORE
IMPORTANTLY...DRIER AIR TO MAKE IT INTO THE EAST BY EVENING AS A BACK
DOOR COLD FRONT PUSHES WEST THROUGH THE AREA ALLOWING SOME LOWS
CLOSER TO NORMAL FOR THIS TIME OF YEAR IN THE FAR EAST BY DAWN
MONDAY. AGAIN PATCHY FOG WILL BE A CONCERN DEPENDING ON THE RAINS
OF THE PREVIOUS DAY AND CLEARING THAT NIGHT.
STUCK WITH THE CONSSHORT AS A STARTING POINT FOR THE T/TD/WINDS
THROUGH THE FIRST 24 HOURS AND THE SUPERBLEND THEREAFTER. MADE SOME
MINOR ADJUSTMENTS BASED ON TERRAIN FOR LOWS TONIGHT AND SUNDAY
NIGHT. AS FOR POPS...ENDED UP CLOSER TO THE WETTER MET GUIDANCE
TONIGHT AND THEN NEARER THE MAV NUMBERS FOR THE REST OF THE SHORT
TERM PORTION OF THE FORECAST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 239 PM EDT SAT AUG 23 2014
STRONG RIDGING WILL DOMINATE THE EASTERN CONUS THROUGH NEXT WEEK
WITH SUMMER-LIKE WEATHER CONTINUING. FORTUNATELY...WITH A STRONGER
CAP PRESENT...CONVECTION WILL BE HELD MORE AT BAY. CANNOT RULE OUT A
STRAY AFTERNOON SHOWER OR STORM EACH DAY...BUT SHOULD BE NOTHING
LIKE WE HAVE SEEN LATELY. PLANNING TO GO WITH A DIURNAL TREND WITH
POPS THROUGH THE END OF THE PERIOD WITH POPS PEAKING EACH AFTERNOON
WITH MAXIMUM HEATING/INSTABILITY. A SURFACE TROUGH MAY APPROACH FROM
THE WEST EARLY NEXT WEEKEND...BUT A TROPICAL SYSTEM DEVELOPING OVER
THE ATLANTIC BASIN...MAY HAVE A TENDENCY TO SLOW DOWN THE
ADVANCEMENT OF THIS FEATURE UNTIL SOMETIME LATE IN THE WEEKEND OR
THE FOLLOWING WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 200 PM EDT SAT AUG 23 2014
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE A CONCERN INTO THE
EVENING FOR ALL SITES...THOUGH THE BEST CHANCES WILL BE HAD AT LOZ
AND SME. WITH ANY STORMS...EXPECT LOWER CIGS...INTO THE MVFR
RANGE...AND A POTENTIAL FOR IFR VIS. OTHERWISE...VFR WILL PREVAIL
INTO THE EVENING. THE AMPLE BOUNDARY LAYER MOISTURE AND PARTIAL
CLEARING EXPECTED TONIGHT SHOULD SET THE STAGE FOR ROBUST FOG
DEVELOPMENT THROUGH THE ENTIRE AREA. ACCORDINGLY HAVE BROUGHT IN
DENSE...VLIFR...FOG AT ALL SITES LATE TONIGHT. THE FOG BURNS OFF BY
14Z SUNDAY WITH VRF CONDITIONS ANTICIPATED AHEAD OF SCATTERED STORM
DEVELOPMENT IN THE AFTERNOON FOR WESTERN PARTS OF THE AREA. WINDS
THROUGH THE PERIOD WILL BE MAINLY LIGHT AND VARIABLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
242 PM EDT SAT AUG 23 2014
.SYNOPSIS...
A FRONTAL BOUNDARY ACROSS THE MID ATLANTIC STATES WILL MOVE SOUTHWEST
OF THE AREA TODAY. HIGH PRESSURE FROM NEW ENGLAND SLOWLY BUILDS
INTO THE AREA TONIGHT INTO SUNDAY...BEFORE SETTLING OVER THE
PIEDMONT EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE HRRR AND RUC ALL INDICATE THE SHOWERS OVER THE SW PART OF THE
CWA WILL CONTINUE SE AND EXIT THE AREA BY EARLY AFTERNOON. OTHER
SHOWERS OVER MD WILL MOVE INTO THE NORTHERN NECK AND THE DELMARVA
DURING THE EARLY AFTERNOON. THESE WILL BE WEAKENING AS THEY
ENCOUNTER DRIER AIR. HAVE RAISED POPS SOME ALONG THE LINES OF BOTH
AREAS OF SHOWERS. ALSO HAVE LOWERED THE MAX TEMPERATURE A LITTLE
AS NOT MUCH SUNSHINE TODAY AND WITH WINDS COMING OFF THE OCEAN
WILL HELP TO KEEP TEMPERATURES LOWER.
PREVIOUS DISCUSSION...LATEST SFC ANALYSIS REVEALS HI PRES CENTERED OVR NEW
ENGLAND AND A DISORGANIZED PRES FIELD OVR THE MID ATLANTIC REGION
COINCIDING WITH A WEAK STALLED FRNTAL BNDRY. ALOFT...NW FLOW
CONTINUES WITH AN UPR-LEVEL RIDGE CENTERED OVR THE E-CNTRL CONUS.
THE SFC FRNT WILL SAG S INTO THE CAROLINAS TDA. EXPECT ANOTHER DAY
WITH SCT SHRAS/TSTMS...ESPECIALLY OVR THE PIEDMONT CLOSER TO THE
FRNT. THE POTENTIAL FOR THUNDER WILL BE CONFINED AWAY FROM THE
CSTS DUE TO NE FLOW WITH HI PRES BLDG OVR NEW ENGLAND. NOT
EXPECTING ANY SVR WX BUT HEAVY RAIN IS PSBL IN SOME AREAS. AFTN HI
TEMPS WILL RANGE FM THE UPR 70S TO NEAR 80 OVR THE LWR ERN SHORE
TO THE LO-MID 80S ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
THE HIGH SURGES SSW OVER THE AREA TONIGHT INTO SUNDAY WITH THE
SURFACE RIDGE AXIS SETTLING OVER THE PIEDMONT BY MONDAY. THIS WILL
PRODUCE A DRYING TREND ALONG WITH A NE WIND THAT SHOULD BE RATHER
BREEZY ALONG THE COAST. PARTLY TO MOSTLY SUNNY CONDITIONS ARE
EXPECTED BY SUNDAY...WITH MOSTLY CLEAR/SUNNY CONDITIONS BY SUNDAY
NIGHT AND MONDAY.
HIGHS WILL BE BELOW SEASONAL AVERAGES THROUGH MONDAY (AROUND -1
ST DEV). HIGHS SUNDAY AND MONDAY WILL RANGE FROM THE UPPER 70S TO
LOW 80S. LOWS SHOULD BE IN THE MID/UPPER 60S SUNDAY MORNING...WITH
MAINLY LOW/MID 60S EXPECTED MONDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
SFC HIGH PRESSURE AND UPPER LEVEL RIDGING ALONG THE EASTERN SEABOARD
IS EXPECTED TO CONTINUE THROUGH MID NEXT WEEK. THIS PATTERN WILL
MAINTAIN A COOLER AIRMASS OVER THE AREA THROUGH WED BEFORE THE
RIDGE AXES AT THE SFC AND ALOFT ALOFT BEGIN TO SHIFT JUST EAST OF
THE FA...AND MOVING OFFSHORE BY THU. THE FORECAST IS GENERALLY DRY
THROUGH THE EXTENDED FORECAST PERIODS DUE TO WELL-ESTABLISHED
SUBSIDENCE THROUGH THE ATMOSPHERIC PROFILE...HOWEVER A FEW SHOWERS
CANNOT BE RULED OUT NEAR THE FAR SE VA/NE NC COAST ON WED DUE TO
THE POTENTIAL FOR WRAPAROUND MOISTURE FROM THE TROPICAL SYSTEM
PASSING WELL TO THE EAST. HIGH AND LOW TEMPERATURES WILL RUN BELOW
NORMAL FROM MON NIGHT THROUGH WED NIGHT (LOWS IN THE 60S...UPPER
50S FAR WRN COUNTIES/HIGHS IN THE LOW-MID 80S...MID-UPPER 70S
BEACHES) AND THEN REBOUND TWD SEASONAL NORMALS THU/THU NIGHT
(HIGHS IN THE MID-UPPER 80S...UPPER 70S-LOWER 80S BEACHES/LOWS IN
THE MID-UPPER 60S...AROUND 70 BEACHES).
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
MVFR SHOWERS AND CEILINGS WILL PERSIST OVERNIGHT DUE TO THE
SATURATED AIRMASS ACROSS THE AREA. HIGH PRESSURE TO THE NORTH WILL
CONTINUE TO BUILD SOUTH PUSHING DRIER AIR INTO THE MID-ATLANTIC.
THIS WILL HELP CLEAR THE SHOWERS AND CEILINGS BY SUNDAY MORNING.
EXPECT VFR CONDITIONS TO PREVAIL SUN AFTN WITH A CONTINUED NE
WIND.
OUTLOOK...DRY WEATHER IS FORECAST FOR SEVERAL DAYS BEGINNING
SUNDAY AS MID AND LOWER RIDGING TAKES PLACE OVER THE AREA.
&&
.MARINE...
FRONTAL BOUNDARY NOW SOUTH OF THE AREA WITH HIGH PRESSURE BUILDING
SOUTH FROM NEW ENGLAND. DESPITE THE ONGOING E-NE WINDS...LATEST
GUIDANCE NOT AS BULLISH WITH THE WINDS THUS CREATING SOME DOUBT
WHEN SCA CONDITIONS WILL START. TOUGHEST CALL WILL BE SOUTHERN CHES
BAY WHERE ONLY MINIMAL CONDITIONS WILL BE MEET. MOUTH OF THE BAY
WILL HAVE AN EARLIER START AND LATER FINISH TIME. SEAS (ESPECIALLY
OUT NEAR 20 NM) ARE EXPECTED TO BUILD TO 5 FEET THEN REMAIN THERE
THROUGH EARLY NEXT WEEK...SO EXTENDED THE SCA HEADLINES OVR THE
WATERS THRU SUNDAY NIGHT. FOR CONTINUITY SAKE...WENT AHEAD AND
HOISTED SCA HEADLINES FOR CURRITUCK SND SUN AND SUN NIGHT AS SCNDRY
SURGE WILL LIKELY KEEP WINDS BTWN 15-20 KTS.
FORECAST NEXT WEEK WILL DEPEND ON THE TRACK OF A DEVELOPING
(TROPICAL) LOW PROGGED TO TRACK NE BUT REMAIN EAST OF GULF STREAM
WALL. SWELL FROM THIS SYSTEM WILL EVENTUALLY AFFECT THE MID ATLNTC
BEACH AREAS.
&&
.TIDES/COASTAL FLOODING...
TIDES PROGGED TO BUILD TO ABOUT 1 FOOT ABOVE NORMAL EARLY NEXT WEEK
AS THE NE FLOW CONTINUES. DESPITE THE PERSISTENT ONSHORE FLOW...LEVELS
EXPECTED TO REMAIN ABOUT 1/2 FOOT BELOW MINOR FLOODING THRESHOLDS.
WENT WITH A MODERATE RIP CURRENT THREAT TODAY GIVEN NEARSHORE WAVES
OF 2-3 FT AND A INCREASING NE WIND FLOW.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
MDZ025.
NC...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
NCZ102.
VA...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
VAZ098>100.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EDT MONDAY
FOR ANZ634.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT SUNDAY
FOR ANZ632.
SMALL CRAFT ADVISORY FROM 8 AM SUNDAY TO 6 AM EDT MONDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT MONDAY
FOR ANZ654.
SMALL CRAFT ADVISORY FROM 2 AM SUNDAY TO 6 AM EDT MONDAY FOR
ANZ656-658.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT MONDAY
FOR ANZ650-652.
&&
$$
SYNOPSIS...AJZ/MAS
NEAR TERM...MAS/JAB
SHORT TERM...AJZ/MAS
LONG TERM...BMD
AVIATION...DAP
MARINE...MPR
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1054 AM EDT SAT AUG 23 2014
.SYNOPSIS...
A FRONTAL BOUNDARY ACROSS THE MID ATLANTIC STATES WILL MOVE SOUTHWEST
OF THE AREA TODAY. HIGH PRESSURE FROM NEW ENGLAND SLOWLY BUILDS
INTO THE AREA TONIGHT INTO SUNDAY...BEFORE SETTLING OVER THE
PIEDMONT EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE HRRR AND RUC ALL INDICATE THE SHOWERS OVER THE SW PART OF THE
CWA WILL CONTINUE SE AND EXIT THE AREA BY EARLY AFTERNOON. OTHER
SHOWERS OVER MD WILL MOVE INTO THE NORTHERN NECK AND THE DELMARVA
DURING THE EARLY AFTERNOON. THESE WILL BE WEAKENING AS THEY
ENCOUNTER DRIER AIR. HAVE RAISED POPS SOME ALONG THE LINES OF BOTH
AREAS OF SHOWERS. ALSO HAVE LOWERED THE MAX TEMPERATURE A LITTLE
AS NOT MUCH SUNSHINE TODAY AND WITH WINDS COMING OFF THE OCEAN
WILL HELP TO KEEP TEMPERATURES LOWER.
PREVIOUS DISCUSSION...LATEST SFC ANALYSIS REVEALS HI PRES CENTERED OVR NEW
ENGLAND AND A DISORGANIZED PRES FIELD OVR THE MID ATLANTIC REGION
COINCIDING WITH A WEAK STALLED FRNTAL BNDRY. ALOFT...NW FLOW
CONTINUES WITH AN UPR-LEVEL RIDGE CENTERED OVR THE E-CNTRL CONUS.
THE SFC FRNT WILL SAG S INTO THE CAROLINAS TDA. EXPECT ANOTHER DAY
WITH SCT SHRAS/TSTMS...ESPECIALLY OVR THE PIEDMONT CLOSER TO THE
FRNT. THE POTENTIAL FOR THUNDER WILL BE CONFINED AWAY FROM THE
CSTS DUE TO NE FLOW WITH HI PRES BLDG OVR NEW ENGLAND. NOT
EXPECTING ANY SVR WX BUT HEAVY RAIN IS PSBL IN SOME AREAS. AFTN HI
TEMPS WILL RANGE FM THE UPR 70S TO NEAR 80 OVR THE LWR ERN SHORE
TO THE LO-MID 80S ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
THE HIGH SURGES SSW OVER THE AREA TONIGHT INTO SUNDAY WITH THE
SURFACE RIDGE AXIS SETTLING OVER THE PIEDMONT BY MONDAY. THIS WILL
PRODUCE A DRYING TREND ALONG WITH A NE WIND THAT SHOULD BE RATHER
BREEZY ALONG THE COAST. PARTLY TO MOSTLY SUNNY CONDITIONS ARE
EXPECTED BY SUNDAY...WITH MOSTLY CLEAR/SUNNY CONDITIONS BY SUNDAY
NIGHT AND MONDAY.
HIGHS WILL BE BELOW SEASONAL AVERAGES THROUGH MONDAY (AROUND -1
ST DEV). HIGHS SUNDAY AND MONDAY WILL RANGE FROM THE UPPER 70S TO
LOW 80S. LOWS SHOULD BE IN THE MID/UPPER 60S SUNDAY MORNING...WITH
MAINLY LOW/MID 60S EXPECTED MONDAY MORNING.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
SFC HIGH PRESSURE AND UPPER LEVEL RIDGING ALONG THE EASTERN SEABOARD
IS EXPECTED TO CONTINUE THROUGH MID NEXT WEEK. THIS PATTERN WILL
MAINTAIN A COOLER AIRMASS OVER THE AREA THROUGH WED BEFORE THE
RIDGE AXES AT THE SFC AND ALOFT ALOFT BEGIN TO SHIFT JUST EAST OF
THE FA...AND MOVING OFFSHORE BY THU. THE FORECAST IS GENERALLY DRY
THROUGH THE EXTENDED FORECAST PERIODS DUE TO WELL-ESTABLISHED
SUBSIDENCE THROUGH THE ATMOSPHERIC PROFILE...HOWEVER A FEW SHOWERS
CANNOT BE RULED OUT NEAR THE FAR SE VA/NE NC COAST ON WED DUE TO
THE POTENTIAL FOR WRAPAROUND MOISTURE FROM THE TROPICAL SYSTEM
PASSING WELL TO THE EAST. HIGH AND LOW TEMPERATURES WILL RUN BELOW
NORMAL FROM MON NIGHT THROUGH WED NIGHT (LOWS IN THE 60S...UPPER
50S FAR WRN COUNTIES/HIGHS IN THE LOW-MID 80S...MID-UPPER 70S
BEACHES) AND THEN REBOUND TWD SEASONAL NORMALS THU/THU NIGHT
(HIGHS IN THE MID-UPPER 80S...UPPER 70S-LOWER 80S BEACHES/LOWS IN
THE MID-UPPER 60S...AROUND 70 BEACHES).
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
KEPT A TEMPO GROUP FOR -RA NEXT FEW HOURS AT KRIC AS THE BATCH OF
RAIN CROSSES THE PIEDMONT. OTW...HIGH PRS TO THE NE ALLOWING FOR
DRYER AIR ALONG THE COAST WITH MAINLY VFR CNDTNS THIS AM. EXPECT
VFR CIGS TODAY WITH TSCTNS SHOWING PLNTY OF MOISTURE ARND THE AREA
FOR A BKN SC DECK (3-4K FT) THRU MUCH OF THE FCST PRD WITH MVFR
CIGS RETURNING AFTER 00Z. SCT CONVECTION PSBL AFTER 18Z...BUT
TIMING OF ANY SHWR/TSTRM PROBLEMATIC AT THIS POINT SO KEPT PCPN
OUT OF FCST AFTER 18Z.
OUTLOOK...MVFR/IFR CONDITIONS PSBL DUE TO STRATUS/FOG SUN MORNING.
OTW...DRY WEATHER IS FORECAST FOR SEVERAL DAYS BEGINNING SUNDAY.
&&
.MARINE...
FRONTAL BOUNDARY NOW SOUTH OF THE AREA WITH HIGH PRESSURE BUILDING
SOUTH FROM NEW ENGLAND. DESPITE THE ONGOING E-NE WINDS...LATEST
GUIDANCE NOT AS BULLISH WITH THE WINDS THUS CREATING SOME DOUBT
WHEN SCA CONDITIONS WILL START. TOUGHEST CALL WILL BE SOUTHERN CHES
BAY WHERE ONLY MINIMAL CONDITIONS WILL BE MEET. MOUTH OF THE BAY
WILL HAVE AN EARLIER START AND LATER FINISH TIME. SEAS (ESPECIALLY
OUT NEAR 20 NM) ARE EXPECTED TO BUILD TO 5 FEET THEN REMAIN THERE
THROUGH EARLY NEXT WEEK...SO EXTENDED THE SCA HEADLINES OVR THE
WATERS THRU SUNDAY NIGHT. FOR CONTINUITY SAKE...WENT AHEAD AND
HOISTED SCA HEADLINES FOR CURRITUCK SND SUN AND SUN NIGHT AS SCNDRY
SURGE WILL LIKELY KEEP WINDS BTWN 15-20 KTS.
FORECAST NEXT WEEK WILL DEPEND ON THE TRACK OF A DEVELOPING
(TROPICAL) LOW PROGGED TO TRACK NE BUT REMAIN EAST OF GULF STREAM
WALL. SWELL FROM THIS SYSTEM WILL EVENTUALLY AFFECT THE MID ATLNTC
BEACH AREAS.
&&
.TIDES/COASTAL FLOODING...
TIDES PROGGED TO BUILD TO ABOUT 1 FOOT ABOVE NORMAL EARLY NEXT WEEK
AS THE NE FLOW CONTINUES. DESPITE THE PERSISTANT ONSHORE FLOW...LEVELS
EXPECTED TO REMAIN ABOUT 1/2 FOOT BELOW MINOR FLOODING THRESHOLDS.
WENT WITH A MODERATE RIP CURRENT THREAT TODAY GIVEN NEARSHORE WAVES
OF 2-3 FT AND A INCREASING NE WIND FLOW.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
MDZ025.
NC...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
NCZ102.
VA...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
VAZ098>100.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EDT MONDAY
FOR ANZ634.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 PM EDT SUNDAY
FOR ANZ632.
SMALL CRAFT ADVISORY FROM 8 AM SUNDAY TO 6 AM EDT MONDAY FOR
ANZ633.
SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT MONDAY
FOR ANZ654.
SMALL CRAFT ADVISORY FROM 2 AM SUNDAY TO 6 AM EDT MONDAY FOR
ANZ656-658.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT MONDAY
FOR ANZ650-652.
&&
$$
SYNOPSIS...AJZ/MAS
NEAR TERM...MAS/JAB
SHORT TERM...AJZ/MAS
LONG TERM...BMD
AVIATION...MPR
MARINE...MPR
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1119 PM EDT SUN AUG 24 2014
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 328 PM EDT SUN AUG 24 2014
MONDAY AND TUESDAY WILL SEE WARMER AND MORE HUMID CONDITIONS WITH
SCATTERED THUNDERSTORMS. SOME HEAVIER RAIN IS POSSIBLE TUESDAY
NIGHT AS A COLD FRONT SINKS SOUTH THROUGH LOWER MICHIGAN.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 328 PM EDT SUN AUG 24 2014
FORECAST IMPACTS IN THE NEAR TERM INCLUDE PATCHY FOG TONIGHT ALONG
WITH HEAT INDICES IN THE LOWER 90S MONDAY AND TUESDAY AFTERNOON.
SCATTERED THUNDERSTORMS ARE POSSIBLE AS LIFTED INDICES ARE AROUND
MINUS 6 BOTH DAYS...BUT COVERAGE WILL BE ISOLATED TO SCATTERED
BEFORE THE COLD FRONT ARRIVES LATER TUESDAY TO FOCUS CONVECTION.
SEVERE WEATHER RISK IS LIMITED AS SHEAR REMAINS RELATIVELY WEAK.
FLOODING POTENTIAL IS THERE HOWEVER. SEE HYDROLOGY SECTION FOR
DETAILS. LOOKS LIKE THE MOST FAVORABLE CONDITIONS FOR HEAVY RAIN
OCCUR TUESDAY NIGHT.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 328 PM EDT SUN AUG 24 2014
A COLD FRONT SHOULD BE NEAR THE MI/IN BORDER WEDNESDAY AS HIGH
PRESSURE BUILDS IN FROM WISCONSIN. WE PUSHED POPS A BIT FARTHER
SOUTH WEDNESDAY BUT THE EXACT POSITION OF THE FRONTAL BOUNDARY ISN/T
CERTAIN AT THIS POINT. IT/S LIKELY THOUGH THE THE BULK OF THE PCPN
ASSOCIATED WITH THE BOUNDARY WILL BE OVER NORTHERN INDIANA OR
PERHAPS FAR SOUTHERN LOWER MICHIGAN.
THE BOUNDARY BEGINS LIFTING NORTHWARD THURSDAY IN RESPONSE TO
DEVELOPING LOW PRESSURE IN THE PLAINS. WE/LL KEEP A SLIGHT CHANCE OF
PCPN IN THE GRIDS BUT MOST LOCATIONS WILL BE DRY.
THE BEST CHANCE OF RAIN LOOKS TO BE FRIDAY/SATURDAY WHEN THE LOW
MOVES ENE TOWARD LOWER MICHIGAN AND THE WARM FRONT MOVES NORTH
ACROSS THE CWA. HIGHS WILL BE IN THE MID TO UPPER 70S THROUGH THE
PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1120 PM EDT SUN AUG 24 2014
IT WOULD SEEM FOG IS BECOMING LESS LIKELY OVERNIGHT. AS I WROTE
FOR THE 00Z TAF SET...THE WINDS IN THE BOUNDARY LAYER OF BETWEEN
15 AND 25 KNOTS ARE ENOUGH TO KEEP SURFACE FOG FROM BECOMING MUCH
OF AN ISSUE TONIGHT. INSTEAD THE IR-FOG LOOP SHOWS PATCHY LOW CLOUDS
(MVFR CIGS) DEVELOPING NEAR AND SOUTH OF I-96. AS THE AIR
CONTINUES TO COOL OVERNIGHT THE LOW CLOUDS SHOULD BECOME MORE
EXTENSIVE AND CIGS SHOULD LOWER SOME. SO I HAVE ONLY MVFR CIGS/VSBY
AT ALL TAF SITES.
THE CONVECTION FOR MONDAY STILL SEEMS POSSIBLE. THE LATEST VERSION
OF THE RAP MODEL AND THE NAM12 SHOW LATE MORNING AND AFTERNOON
CONVECTION. SO...I NOW HAVE VCTS AFTER 15Z FOR THAT. I WOULD
EXPECT ONCE THE SUN SETS MONDAY EVENING THE CONVECTION WILL BE
DONE. THERE SHOULD BE ENOUGH WIND TOMORROW NIGHT TO KEEP FOG FROM
BECOMING AN ISSUE.
&&
.MARINE...
ISSUED AT 328 PM EDT SUN AUG 24 2014
WINDS WILL VEER TO THE SOUTH ON MONDAY BUT WAVES WILL ONLY BUILD
TO AROUND 2 FEET AS FLOW WILL BE RELATIVELY LIGHT. VISIBILITY COULD
BE REDUCED AT TIMES IN FOG TONIGHT THROUGH TUESDAY. THUNDERSTORMS
ARE POSSIBLE MONDAY AND TUESDAY AFTERNOONS.
&&
.HYDROLOGY...
ISSUED AT 1104 AM EDT SUN AUG 24 2014
BEST CHANCE FOR SIGNIFICANT RAINFALL WOULD BE MONDAY NIGHT THROUGH
WEDNESDAY WITH A SLOW MOVING COLD FRONT. THIS IS NOT A GUARANTEE
AS THE LLJ IS FORECAST TO BE QUITE WEAK. NEVERTHELESS...A VERY
MOIST ATMOSPHERE COMBINED WITH FORCING VIA THE COLD FRONT AND SLOW
CELL MOVEMENT COULD RESULT IN SOME SIGNIFICANT RAINFALL IF STORMS
DEVELOP OVER OUR AREA. PW VALUES WILL LIKELY BE AROUND 1.75"
MONDAY NIGHT AND TUESDAY. MODEL GUIDANCE IS MIXED REGARDING HOW
LONG THE FRONT MAY HANG UP...SO IT IS UNCLEAR WHEN THE THREAT FOR
SIGNIFICANT RAINFALL WOULD END.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...93
AVIATION...WDM
HYDROLOGY...HOVING
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS GAYLORD MI
405 PM EDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 405 PM EDT SAT AUG 23 2014
HIGH PRESSURE TO OUR EAST WILL PROVIDE FOR LIGHT SOUTHERLY
BREEZES...AND INCREASING WARMTH AND HUMIDITY THROUGH MONDAY. FOR THE
MOST PART THE WEEKEND LOOKS DRY...BUT SHOWERS AND THUNDERSTORM
CHANCES WILL INCREASE ON MONDAY...AHEAD OF A WEAK COLD FRONT THAT
WILL ENTER NORTHERN MICHIGAN MONDAY NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 405 PM EDT SAT AUG 23 2014
SHARP MID LEVEL RIDGE AXIS CONTINUES TO POKE UP INTO THE WESTERN
GREAT LAKES ROUGHLY FROM EASTERN WISCONSIN UP THROUGH CENTRAL
UPPER MICHIGAN...DOWNSTREAM OF STRONG SHORT WAVE TROUGHING ACROSS
THE NRN ROCKIES INTO THE NRN PLAINS. BROAD LOW PRESSURE ACROSS THE
CENTRAL PLAINS WITH A SFC WARM FRONT DRAPED ACROSS MISSOURI INTO
THE OHIO RIVER VALLEY. ELEVATED WARM FRONT AND THETA-E PLUME
HAS SPREAD NORTHWARD ACROSS THE MIDWEST INTO THE LOWER GREAT
LAKES AND CONTINUES TO BE THE MAIN WEATHER FOCUS WITH YET ANOTHER
ROUND OF CONVECTION WORKING ACROSS THE MIDWEST THIS AFTERNOON.
ACROSS THE NRN GREAT LAKES...WEAK HIGH PRESSURE IS DRAPED ACROSS
NRN MICHIGAN. BUT...SUBTLE LOW-MID LEVEL TROUGH AXIS ANALYZED
ACROSS WESTERN/CENTRAL UPPER MICHIGAN ALONG NE FRINGE OF DEEPER
MOISTURE GRADIENT...WHERE RUC ANALYSIS CONTINUES TO DEPICT A
STRONG LOW-MID LEVEL DEFORMATION AXIS STRETCHING FROM NRN LAKE
MICHIGAN UP THROUGH CENTRAL UPPER MICHIGAN. THIS HAS/IS GENERATING
A BAND OF SHOWERS UP THROUGH THAT AREA PARTICULARLY AROUND THE
ESCANABA AREA (TERRAIN INFLUENCED) TRYING TO BLEED ACROSS NRN LAKE
MICHIGAN ALTHOUGH PRECIP APPEARS TO FINALLY BE WINDING DOWN. SOME
HEATING INDUCED CONVECTION ALSO ONGOING IN NE WISCONSIN WITHIN THE
BETTER MOISTURE FIELD. ACROSS NRN LOWER MICHIGAN...STUBBORN LAKE
STRATUS IN EASTERN UPPER AND NE LOWER MICHIGAN HAS MOSTLY MIXED
OUT INTO A FLAT CU FIELD. NO SIGNS OF ANY PRECIP. BUT SOLID LAKE
STRATUS REMAINS LOCKED ACROSS WESTERN LAKE HURON INTO THE
STRAITS...SIGNS OF THINGS TO COME I THINK.
TONIGHT...NO PRECIP AS MAIN FOCUS WILL REMAIN WEST-THROUGH-SOUTH OF
NRN MICHIGAN. WILL ENJOY A FEW HOURS OF CLR TO PARTLY CLOUDY SKIES
THIS EVENING AS HEATING INDUCE CU/STCU DECK FADES AWAY. BUT WITH
PERSISTENT EASTERLY FLOW JUST OFF THE DECK...VEERING SOUTHEAST
OVERNIGHT...SUSPECT MARINE LAYER/LAKE STRATUS AND FOG OUT ACROSS
LAKE HURON WILL ONCE AGAIN GET SCOOPED INTO EASTERN UPPER MICHIGAN
AND NORTHEAST LOWER MICHIGAN DURING THE OVERNIGHT HOURS. HAVE
TAILORED THE FORECAST THAT WAY ALONG WITH PATCHY TO AREAS OF FOG
OVERNIGHT. A REPEAT ON TEMPS WITH A BIT OF A MUGGY NIGHT
(RELATIVELY SPEAKING) AND LOWS IN THE UPPER 50S TO MIDDLE 60S.
&&
.LONG TERM...(SUNDAY THROUGH SATURDAY)
ISSUED AT 405 PM EDT SAT AUG 23 2014
...WARM START...COOLER FINISH TO THE UPCOMING WEEK...
HIGH IMPACT WEATHER POTENTIAL: MINIMAL. SOME THUNDER POTENTIAL AT
TIMES THIS WEEK.
PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: AMPLIFIED PATTERN SOO TALKED
ABOUT THE LAST SEVERAL DAYS LOOKS TO REACH MATURATION SUNDAY...WHEN
MOST IMPRESSIVE RIDGE AXIS/HEAT DOME OF THIS SUMMER BUILDS DIRECTLY
OVERHEAD AND UP INTO SOUTHEAST CANADA. WESTERN TROUGHING
CONTINUES...WITH LEAD EJECTING RATHER ROBUST SHORTWAVE LOOKING TO
PUT A KIBOSH ON FURTHER RIDGE AMPLIFICATION HEADING INTO THE START OF
NEXT WORK WEEK. PATTERN THERE-ON-AFTER LOOKS TO BECOME AN
INCREASINGLY FLATTER ONE AS STRONGEST CORES OF UPPER LEVEL JET ENERGY
SLICE WEST/EAST ACROSS SOUTHERN CANADA. A CHANGEABLE PATTERN FOR
SURE...AND ONE THAT SIMPLE FORCES ANOTHER EXTENDED STRETCH OF LOW
CONFIDENCE SHOWER AND STORM FORECAST EVOLUTION.
PRIMARY FORECAST CONCERNS/CHALLENGES: JUST HOW WARM TO GO
SUNDAY/MONDAY AND ADDRESSING WHAT INITIALLY LOOKS TO BE MULTI-PERIOD
SHOWER AND THUNDERSTORM CHANCES RIGHT THROUGH THE WEEK.
DETAILS: TAKE TODAY`S WEATHER...TACK ON A FEW DEGREES...SUNDAYS
WEATHER DONE! MORE SIGNIFICANT CHANGES TAKE PLACE MONDAY AS RIDGE
APEX PUSHES EAST AND EARLIER MENTIONED SHORTWAVE PUNCHES UP INTO SOUTH
CENTRAL CANADA. SOUTHWEST FLOW RAMPS UP IN RESPONSE...DRIVING A GOOD
CHUNK OF CURRENT SOUTHERN PLAINS HEAT DOME ALONG WITH IT. H8 TEMPS
MAKE A RUN INTO THE UPPER TEENS...READINGS NOT YET SEEN AROUND THESE
PARTS THIS SUMMER. INCREASING PRESSURE GRADIENT ON FRONT SIDE OF
APPROACHING/ALBEIT STEADILY DECAYING/COLD FRONT SHOULD ONLY HELP THE
SURFACE WARMING CAUSE. TEMPERATURES WELL INTO THE 80S A SURE BET FOR
AREAS SOUTH OF THE BIG BRIDGE...AND NOT OUT OF THE REALM OF
POSSIBILITY A FEW FAVORED DOWNSLOPE AREAS OF NORTHEAST LOWER MAKE A
RUN A 90. NOW...THAT SAME FRONT MAY BRING A SHOWER AND STORM THREAT
ALONG WITH IT. DEFINITELY NOT ENTIRELY SOLD ON THIS IDEA GIVEN FAR
REMOVED MID LEVEL SUPPORT AND QUICKLY DECAYING FORCED SURFACE
CONVERGENCE. ATMOSPHERE ALSO HAS THE LOOK OF BEING RATHER
CAPED...WITH NOTED H8 WARM NOSE. WHILE OVERALL AIRMASS BECOMES
INCREASINGLY MOIST...SET-UP SCREAMS OF DECENT LOW LEVEL MIXING OUT
OF MOISTURE...AND STARTING TO WONDER IF PROGGED UPPER 60 DEWPOINTS
ARE SEVERAL DEGREES TOO HIGH. NO DOUBT ABOVE LEAVES PLENTY OF
OPPORTUNITY FOR A DRY LATE MONDAY FRONTAL PASSAGE. INHERITED LOW
CHANCES WILL DO FOR NOW...BUT TRULY BELIEVE MANY WILL SEE
LITTLE...IF ANY...RAIN.
SAID FRONT LOOKS TO SIGNIFICANTLY SLOW ITS SOUTH PROGRESS MONDAY
NIGHT THROUGH TUESDAY NIGHT AS IT BECOMES INCREASINGLY ALIGNED WITH
DEEP LAYER WESTERLY FLOW. JUST WHERE IT STALLS OUT IS OPEN TO PLENTY
OF DEBATE...BUT GIVEN BREADTH OF PREFRONTAL WARMING AND TOTAL
DETACHMENT OF ANY MID LEVEL SUPPORT...KINDA FEEL IT MAY STRUGGLE TO
CLEAR OUR SOUTHERN COUNTIES UNTIL SOMETIME TUESDAY NIGHT. NOW...THAT
LEADS TO A TRICKY TEMPERATURE AND SHOWER FORECAST RIGHT THROUGH MID
WEEK. AS FOR TEMPERATURES...TUESDAY HAS THE POTENTIAL TO BE
DOWNRIGHT WARM...ESPECIALLY FOR AREAS NEAR SAGINAW BAY...WHERE
TEMPERATURES MAY ONCE AGAIN REACH INTO THE MID AND UPPER 80S. COOLER
AIR ARRIVES WEDNESDAY...WITH HIGHS MOSTLY IN THE 70S (ALL DEPENDENT
ON THAT WHOLE FRONTAL TIMING THING OF COURSE). NEARLY ALL GUIDANCE
REMAINS STEADFAST ON ADDITIONAL SHOWER/STORM DEVELOPMENT ALONG AND
NORTH OF THE SURFACE FRONT AS WEAK MID LEVEL IMPULSES RIDE ALONG IT
MONDAY NIGHT RIGHT INTO WEDNESDAY. ANY DECENT SUPPORT IS FAR FROM
CERTAIN...AND JUST NOT BUYING THIS WET LOOK IN GUIDANCE. MUCH LIKE
MONDAY...LOWER POPS THE WAY TO GO FOR NOW...WITH PLENTY OF TIME TO
WORK ON BETTER TEMPORAL AND SPATIAL RESOLUTION OF SHOWER/STORM
CHANCES IN THE COMING DAYS.
SOME HINTS WHAT IS LEFT OF WESTERN TROUGHING GETS SHUNTED EAST LATE
IN THE WEEK...FORCING FRONT BACK NORTH AND DRUMMING UP ADDITIONAL
RAIN CHANCES TO START NEXT WEEKEND. TIMING WILL CHANGE...AND A
SIMPLE CONSENSUS BLEND APPROACH WILL BE UTILIZED FOR NOW....WHICH
INDEED HOLDS OFF NEXT MENTION FOR SHOWERS/STORMS UNTIL FRIDAY NIGHT
AND SATURDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 132 PM EDT SAT AUG 23 2014
STUBBORN STRATUS DECK FLOWING OFF LAKE HURON ON EASTERLY WINDS
CONTINUES TO BRING MVFR FLIGHT CONDITIONS TO PLN/APN...ALTHOUGH
STRATUS DECK HAS/IS SLOWLY ERODING. CLOUDS SHOULD SCATTER OUT BY
MID TO LATE AFTERNOON AT THOSE SITES LEAVING A PERIOD OF VFR
CONDITIONS HEADING INTO THE EVENING. VFR CONDITIONS AT TVC AND MBL
WILL PERSIST.
TONIGHT...FEAR CYCLE WILL REPEAT AS MARINE STRATUS ONCE AGAIN
REDEVELOPS OFF THE LAKE INTO NE LOWER MICHIGAN...LATER THIS
EVENING AND FOR THE OVERNIGHT HOURS WITHIN PERSISTENT E/SE FLOW.
THUS...HAVE IFR CIGS AND LOW VSBYS ONCE AGAIN TAKING OFF AT
APN/PLN THROUGH THE COURSE OF THE NIGHT WHILE TVC/MBL REMAIN
LARGELY VFR WITH SOME MINOR REDUCTIONS TO VSBY DUE TO LIGHT FOG.
WINDS...LIGHT EASTERLY TODAY...CALM TONIGHT AND LIGHT SE ON
SUNDAY.
&&
.MARINE...
ISSUED AT 405 PM EDT SAT AUG 23 2014
ABUNDANT MARINE STRATUS AND FOG WILL CONTINUE TO IMPACT THE NEARSHORE
AREAS OF NRN LAKE HURON INTO THE SAINT MARYS RIVER SYSTEM...TONIGHT
INTO SUNDAY BEFORE STRONGER SOUTHERLY WINDS DEVELOP LATER SUNDAY
INTO MONDAY AND FINALLY SCOURS OUT THE STRATUS/FOG.
OTHERWISE...LIGHT EASTERLY WINDS TONIGHT WILL VEER MORE SOUTHEASTERLY
THEN SOUTH ON SUNDAY...INCREASING SUNDAY NIGHT INTO MONDAY. MAY
DEVELOP ENOUGH GUSTINESS TO WARRANT SMALL CRAFT ADVISORIES FOR
PARTS OF NRN LAKE MICHIGAN BY MONDAY MORNING...ALTHOUGH LAKE
STABILITY MAY KEEP WINDS/WAVES IN CHECK.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
SYNOPSIS...AM
SHORT TERM...ADAM
LONG TERM...MSB
AVIATION...ADAM
MARINE...ADAM
AREA FORECAST DISCUSSION
NWS GAYLORD MI
133 PM EDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 246 AM EDT SAT AUG 23 2014
HIGH PRESSURE TO OUR EAST WILL PROVIDE FOR LIGHT SOUTHERLY
BREEZES...AND INCREASING WARMTH AND HUMIDITY THROUGH MONDAY. FOR
THE MOST PART THE WEEKEND LOOKS DRY...BUT SHOWERS AND THUNDERSTORM
CHANCES WILL INCREASE ON MONDAY...AHEAD OF A WEAK COLD FRONT
THAT WILL ENTER NORTHERN MICHIGAN MONDAY NIGHT.
&&
.UPDATE...
ISSUED AT 1111 AM EDT SAT AUG 23 2014
SHARP MID LEVEL RIDGE AXIS CONTINUES TO POKE UP INTO THE WESTERN
GREAT LAKES...DOWNSTREAM OF STRONG SHORT WAVE TROUGHING ACROSS THE
NRN ROCKIES INTO THE NRN PLAINS. BROAD LOW PRESSURE ACROSS THE
CENTRAL PLAINS WITH A SFC WARM FRONT DRAPED ACROSS THE MIDWEST
INTO THE OHIO VALLEY...AND CONTINUES TO BE THE MAIN WEATHER FOCUS
WITH YET ANOTHER ROUND OF CONVECTION IN THE MIDWEST.
ACROSS NRN MICHIGAN...A BUNCH OF LITTLE THINGS HAPPENING. WEAK
HIGH PRESSURE IS DRAPED ACROSS NRN MICHIGAN. BUT...SUBTLE LOW-MID
LEVEL TROUGH AXIS ANALYZED ACROSS WESTERN/CENTRAL UPPER MICHIGAN
ALONG NE FRINGE OF DEEPER MOISTURE GRADIENT...WHERE RUC ANALYSIS
REVEALS A STRONG LOW-MID LEVEL DEFORMATION AXIS STRETCHING FROM
NRN LAKE MICHIGAN UP THROUGH CENTRAL UPPER MICHIGAN. THIS IN TURN
HAS/IS GENERATING A BAND OF SHOWERS UP THROUGH THAT AREA. ONE
POCKET OF RAIN IN PARTICULAR HAS SEEMINGLY LATCHED ON TO THE
TERRAIN INCREASE OFF LAKE MICHIGAN AND HAS BROUGHT SOME LOCALLY
HEAVY RAIN THROUGH THAT AREA.
NOTHING LIKE THAT HAPPENING HERE. BUT...BATCH OF VERY STUBBORN
STRATUS CONTINUES TO FLOW OFF LAKE HURON WITHIN EASTERLY
FLOW...BRINGING CLOUDY SKIES TO PARTS OF EASTERN UPPER AND NE
LOWER MICHIGAN. STRATUS IS BEGINNING TO ERODE...BUT PROCESS IS
TAKING IT/S TIME.
REST OF TODAY...STRATUS IN THE EAST AND IN EASTERN UPPER MICHIGAN
WILL EVENTUALLY ERODE/MIX OUT...BUT IT WILL TAKE SEVERAL MORE
HOURS AS EAST FLOW CONTINUES TO PUMP COOL/MOIST MARINE AIR INTO
THOSE AREAS. HAVE STRETCHED CLOUDY SKIES OUT FOR SEVERAL MORE
HOURS. ELSEWHERE...HEATING INDUCED CLOUD COVER SHOULD DEVELOP OVER
NW LOWER MICHIGAN AND WE MAY SEE SOME OF THAT AFOREMENTIONED
DEFORMATION CLOUD COVER EXPAND DOWN INTO NW LOWER MICHIGAN AS
WELL. SO... EITHER CLOUDY BECOMING PARTLY SUNNY...OR SUNNY
BECOMING PARTLY SUNNY WILL BE THE NAME OF THE GAME THIS AFTERNOON.
TEMPS WILL OF COURSE BE TRICKY GIVEN THE CLOUDS...AND AREAS EAST
OF I-75 WILL END UP WITH THE LOWER READINGS AND HAVE TWEAKED MAX
TEMPS ACCORDINGLY. BUT...IT WILL NOT TAKE MUCH FOR TEMPS TO
REBOUND WHEN THE SUN FINALLY DOES BREAK OUT. JUST HOPE WE DON/T
GET SOME SORT OF DIFFERENTIAL HEATING BOUNDARY ACROSS NRN
LOWER/EASTERN UPPER MICHIGAN THAT POPS OFF CONVECTION THIS
AFTERNOON. THINK WE ARE TOO CAPPED FOR THAT...BUT WILL SEE.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 246 AM EDT SAT AUG 23 2014
HIGH IMPACT WEATHER POTENTIAL: MINIMAL
PRIMARY FORECAST CHALLENGES: DO SHOWERS MOVE INTO NORTHERN MICHIGAN?
CURRENTLY, AS WAS MENTIONED AT THE EARLIER UPDATE, RAIN SHOWERS
UPSTREAM OF THE FORECAST AREA ARE JUST SOUTH OF MQT AND SAW AND
ALONG THE 700 MB DEWPOINT DEPRESSION GRADIENT, AND IN THE LFQ OF THE
500 MB 30 KNOT JET STREAK MOVING THROUGH N WISCONSIN. MAIN FORCING
THAT IS GOING ON OVERNIGHT IS OVER FARTHER SOUTH AND WEST IN
NEBRASKA WHERE THE DEEPER SFC LOW AND 500 MB VORT AND SPEED MAXES
ARE DIGGING. THIS HAS GIVEN RISE TO THE COMPLEX OF STORMS IN THE
CENTRAL PLAINS. THE SFC LOW IN THE E COLORADO IS LINKED BY A SLOWLY
STRENGTHENING FRONT THAT STRETCHES TO THE NE THROUGH N MINNESOTA AND
UP INTO JAMES BAY TO A WEAKER SFC LOW.
TODAY...THE MODELS ARE IN GOOD AGREEMENT WITH THE
RUC/NAM12/GFS/ECMWF/LOCAL WRF4KM SHOWING THE MORNING ISOLATED
SHOWERS THAT WILL TRY TO PUSH INTO NW LOWER THIS MORNING. HOWEVER,
AS THE 500 MB RIDGE OVER THE UPPER GREAT LAKES CONTINUES TO AMPLIFY,
THE FORCING FOR THE SHOWERS WILL GET PUSHED TO THE NORTH AND WEST
THROUGH THE AFTERNOON. THE FRONT WILL ALSO MOVE TO THE NORTH AND
WEST AS THE SFC LOW IN E COLORADO MOVES OUT OVER THE CENTRAL PLAINS
AND DEEPENS. THIS WILL HELP TO FOCUS MOST OF THE RAIN INSTABILITY
AND THE DYNAMIC SUPPORT OVER THE NORTHERN PLAINS AS DEPICTED BY SPC.
TONIGHT...THIS MOVEMENT OF THE SFC LOW OUT OF THE CENTRAL PLAINS
WILL PUSH INTO NORTH DAKOTA OVERNIGHT CONTINUING TO PULL THE FOCUS
AWAY FROM THE UPPER GREAT LAKES. THIS SHOULD CONTINUE OUR RAIN FREE
STREAK (OR AT LEAST OUR MEASURABLE PRECIPITATION) THROUGH THE NIGHT.
WHILE THERE IS SOME INSTABILITY, THE LACK OF A FOCUS AND THE CAPPING
EXPECTED IN THE EVENING (BLAYER CIN 20-40 J/KG) SHOULD INHIBIT ANY
SHOWERS FROM GETTING GOING. IT DOESN`T LOOK LIKE THERE IS MUCH IN
THE WAY OF ELEVATED INSTABILITY AS THE SHOWALTER INDEX OVER N
MICHIGAN AT ITS LOWEST IS ONLY +2C.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 246 AM EDT SAT AUG 23 2014
A HIGHLY AMPLIFIED 500MB RIDGE WILL BE OVERHEAD TO START OUR SUNDAY.
AN EJECTING UPPER LOW FROM THE NORTHERN HIGH PLAINS WILL HAVE TO
CREST THIS RIDGE...AND WILL PASS WELL TO OUR NORTH MONDAY NIGHT.
THIS WILL FLATTEN OUT THE RIDGE...THOUGH IN OUR NECK OF THE WOODS
500MB HEIGHTS WILL HARDLY LOWER AT ALL. STILL...AN ASSOCIATED COLD
FRONT WILL SLOWLY GET DRAGGED INTO THE AREA MONDAY NIGHT. UNTIL THAT
HAPPENS...IT WILL BE SOMETHING OF A CHALLENGE TO GET A PRECIP THREAT
GOING IN THESE PARTS. BUT IT WON/T BE CHALLENGING TO BECOME
INCREASINGLY WARM AND HUMID.
SUNDAY...CORE OF THE 500MB RIDGE STARTS TO SLIDE DOWNSTREAM IN THE
AFTERNOON. THAT CORRESPONDS WITH A SLIGHT UPTICK IN 1000-850MB
RETURN FLOW. HOWEVER...A SHORTWAVE RIDGE ASCENDING INTO THE LARGER
RIDGE WILL HELP KEEP HEIGHTS HIGH. AT THE SAME TIME...SURFACE HIGH
PRESSURE TO OUR EAST WILL STILL EXTEND A TOUCH OF RIDGING INTO
NORTHERN MI. FROM A CONCEPTUAL MODEL STANDPOINT...IT WILL BE
DIFFICULT TO FIRE OFF CONVECTION IN THIS PATTERN UNTIL HEIGHTS ALOFT
FALL. INDEED...THE MODELS ARE NOT INCLINED TO PROG MUCH IF ANY CAPE.
00Z NAM HAS A LATE-DAY AXIS OF A FEW HUNDRED J/KG OF MUCAPE...
HUGGING THE LAKE MI COAST FROM LTL TRAV BAY SOUTH. THIS IS WHERE
LAKE BREEZE CONVERGENCE AND MOISTURE POOLING WILL BE CONCENTRATED...
THANKS TO A BACKGROUND LIGHT SE SYNOPTIC SURFACE WIND. EVEN SO...AN
82/65 PARCEL HAS ABOUT 50J/KG OF CIN TO OVERCOME...THANKS TO 700MB
TEMPS AROUND 9C.
SO WILL MAINTAIN A DRY FORECAST. CAN GENERALLY EXPECT PARTLY SUNNY
SKIES...WILL SOME BUBBLY CU AND MID/HIGH DEBRIS CLOUDS (INSTABILITY
WILL BE MUCH HIGHER W OF LAKE MI). MAX TEMPS UPPER 70S (EASTERN
UPPER...AND NE LOWER COAST)...TO LOW/MID 80S (INTERIOR SW SECTIONS).
SUN NIGHT/MONDAY...SUB-850MB FLOW MAINTAIN AN EASTERLY COMPONENT
INTO THE EVENING...BEFORE VEERING S TO EVEN SSW OVERNIGHT. THAT WILL
ALLOW A JUICIER AND POTENTIALLY UNSTABLE AIRMASS TO FINALLY MAKE
INROADS. HOWEVER...THAT WILL BE SLOW AT 1ST...WITH PERHAPS WESTERN
CHIP/MACK THE ONLY PLACE PROGGED TO SEE SOME CAPE ARRIVE BY MORNING.
THIS COULD ALLOW CONVECTION ORIGINATING IN WI A CHANCE TO GRAZE BY
THAT AREA OVERNIGHT. BUT...GIVEN THE MODELS TEND TO BE TOO QUICK TO
BREAK DOWN RIDGING AND CIN...WILL MAINTAIN A DRY FORECAST FOR SUN
NIGHT.
DEEP MOISTURE/MODERATE INSTABILITY PLUME WILL VERY SLOWLY WORK IN
FROM THE WNW MONDAY...AHEAD OF A COLD FRONT ADVANCING ACROSS WI.
HEIGHTS/TEMPS ALOFT HERE REMAIN HIGH...BUT ACTIVITY SHOULD DEVELOP
UPSTREAM IN WI AND MOVE E AND NE TOWARD WESTERN/NORTHERN
SECTIONS...ESPECIALLY LATER IN THE DAY. WILL MAINTAIN CHANCE POPS BY
AFTERNOON IN THE NW 2/3DS OF THE FORECAST AREA...INCLUDING HIGH
CHANCE (50) POPS IN WESTERN CHIP/MACK.
MIN TEMPS NEAR 60F TO THE MID 60S. MAX TEMPS NEAR 80 TO THE MID
80S...A FEW UPPER 80S POSSIBLE IN THE INTERIOR OF NORTHERN LOWER.
DEW POINTS WILL BE RISING INTO THE MID AND UPPER 60S...SO IT WILL
ALSO BE QUITE STICKY ON MONDAY.
REST OF THE FORECAST...SHAPING UP FOR A FAVORABLE MCS PATTERN
MID-WEEK. A STALLED FRONTAL ZONE (AND A WARM/HUMID AIRMASS) WILL BE
JUST TO OUR SOUTH...WITH FAST ZONAL FLOW IN THE NORTHERN LAKES.
CONSALL GRIDS ARE TRYING TO NUDGE US TOWARD LIKELY POPS IN SOME
PERIODS. AM BACKING AWAY FROM THIS THINKING GIVEN THAT IT/S
CONVECTION WE/RE TALKING ABOUT...AND PRECIP HAS UNDERPERFORMED OVER
THE LAST WEEK OR SO. TEMPS WILL BE DRIFTING BACK TOWARD OR A BIT
UNDER CLIMO BY LATE IN THE WORK WEEK...THOUGH PROBABLY NOT AS COOL
AS THE GFS/MEX GUIDANCE ADVERTISES...AS THE ECMWF IS SLOWER AND LESS
AMPLIFIED WITH THE UPPER TROF THAT PROGRESSES INTO THE PLAINS STATES
MID/LATE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 132 PM EDT SAT AUG 23 2014
STUBBORN STRATUS DECK FLOWING OFF LAKE HURON ON EASTERLY WINDS
CONTINUES TO BRING MVFR FLIGHT CONDITIONS TO PLN/APN...ALTHOUGH
STRATUS DECK HAS/IS SLOWLY ERODING. CLOUDS SHOULD SCATTER OUT BY
MID TO LATE AFTERNOON AT THOSE SITES LEAVING A PERIOD OF VFR
CONDITIONS HEADING INTO THE EVENING. VFR CONDITIONS AT TVC AND MBL
WILL PERSIST.
TONIGHT...FEAR CYCLE WILL REPEAT AS MARINE STRATUS ONCE AGAIN
REDEVELOPS OFF THE LAKE INTO NE LOWER MICHIGAN...LATER THIS
EVENING AND FOR THE OVERNIGHT HOURS WITHIN PERSISTENT E/SE FLOW.
THUS...HAVE IFR CIGS AND LOW VSBYS ONCE AGAIN TAKING OFF AT
APN/PLN THROUGH THE COURSE OF THE NIGHT WHILE TVC/MBL REMAIN
LARGELY VFR WITH SOME MINOR REDUCTIONS TO VSBY DUE TO LIGHT FOG.
WINDS...LIGHT EASTERLY TODAY...CALM TONIGHT AND LIGHT SE ON
SUNDAY.
&&
.MARINE...
ISSUED AT 246 AM EDT SAT AUG 23 2014
OVER THE NEXT 48 HOURS, THE WINDS WILL SLOWLY INCREASE AND VEER
FROM THE EAST TO THE SOUTH LOW PRESSURE NEAR COLORADO DEEPENS AND
MOVES INTO NORTH DAKOTA. SO TODAY THROUGH SUNDAY NIGHT, WILL
EXPECT THAT WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT
CONDITIONS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...ADAM
SYNOPSIS...JZ
SHORT TERM...JL
LONG TERM...JZ
AVIATION...ADAM
MARINE...JL
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1112 AM EDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 246 AM EDT SAT AUG 23 2014
HIGH PRESSURE TO OUR EAST WILL PROVIDE FOR LIGHT SOUTHERLY
BREEZES...AND INCREASING WARMTH AND HUMIDITY THROUGH MONDAY. FOR
THE MOST PART THE WEEKEND LOOKS DRY...BUT SHOWERS AND THUNDERSTORM
CHANCES WILL INCREASE ON MONDAY...AHEAD OF A WEAK COLD FRONT
THAT WILL ENTER NORTHERN MICHIGAN MONDAY NIGHT.
&&
.UPDATE...
ISSUED AT 1111 AM EDT SAT AUG 23 2014
SHARP MID LEVEL RIDGE AXIS CONTINUES TO POKE UP INTO THE WESTERN
GREAT LAKES...DOWNSTREAM OF STRONG SHORT WAVE TROUGHING ACROSS THE
NRN ROCKIES INTO THE NRN PLAINS. BROAD LOW PRESSURE ACROSS THE
CENTRAL PLAINS WITH A SFC WARM FRONT DRAPED ACROSS THE MIDWEST
INTO THE OHIO VALLEY...AND CONTINUES TO BE THE MAIN WEATHER FOCUS
WITH YET ANOTHER ROUND OF CONVECTION IN THE MIDWEST.
ACROSS NRN MICHIGAN...A BUNCH OF LITTLE THINGS HAPPENING. WEAK
HIGH PRESSURE IS DRAPED ACROSS NRN MICHIGAN. BUT...SUBTLE LOW-MID
LEVEL TROUGH AXIS ANALYZED ACROSS WESTERN/CENTRAL UPPER MICHIGAN
ALONG NE FRINGE OF DEEPER MOISTURE GRADIENT...WHERE RUC ANALYSIS
REVEALS A STRONG LOW-MID LEVEL DEFORMATION AXIS STRETCHING FROM
NRN LAKE MICHIGAN UP THROUGH CENTRAL UPPER MICHIGAN. THIS IN TURN
HAS/IS GENERATING A BAND OF SHOWERS UP THROUGH THAT AREA. ONE
POCKET OF RAIN IN PARTICULAR HAS SEEMINGLY LATCHED ON TO THE
TERRAIN INCREASE OFF LAKE MICHIGAN AND HAS BROUGHT SOME LOCALLY
HEAVY RAIN THROUGH THAT AREA.
NOTHING LIKE THAT HAPPENING HERE. BUT...BATCH OF VERY STUBBORN
STRATUS CONTINUES TO FLOW OFF LAKE HURON WITHIN EASTERLY
FLOW...BRINGING CLOUDY SKIES TO PARTS OF EASTERN UPPER AND NE
LOWER MICHIGAN. STRATUS IS BEGINNING TO ERODE...BUT PROCESS IS
TAKING IT/S TIME.
REST OF TODAY...STRATUS IN THE EAST AND IN EASTERN UPPER MICHIGAN
WILL EVENTUALLY ERODE/MIX OUT...BUT IT WILL TAKE SEVERAL MORE
HOURS AS EAST FLOW CONTINUES TO PUMP COOL/MOIST MARINE AIR INTO
THOSE AREAS. HAVE STRETCHED CLOUDY SKIES OUT FOR SEVERAL MORE
HOURS. ELSEWHERE...HEATING INDUCED CLOUD COVER SHOULD DEVELOP OVER
NW LOWER MICHIGAN AND WE MAY SEE SOME OF THAT AFOREMENTIONED
DEFORMATION CLOUD COVER EXPAND DOWN INTO NW LOWER MICHIGAN AS
WELL. SO... EITHER CLOUDY BECOMING PARTLY SUNNY...OR SUNNY
BECOMING PARTLY SUNNY WILL BE THE NAME OF THE GAME THIS AFTERNOON.
TEMPS WILL OF COURSE BE TRICKY GIVEN THE CLOUDS...AND AREAS EAST
OF I-75 WILL END UP WITH THE LOWER READINGS AND HAVE TWEAKED MAX
TEMPS ACCORDINGLY. BUT...IT WILL NOT TAKE MUCH FOR TEMPS TO
REBOUND WHEN THE SUN FINALLY DOES BREAK OUT. JUST HOPE WE DON/T
GET SOME SORT OF DIFFERENTIAL HEATING BOUNDARY ACROSS NRN
LOWER/EASTERN UPPER MICHIGAN THAT POPS OFF CONVECTION THIS
AFTERNOON. THINK WE ARE TOO CAPPED FOR THAT...BUT WILL SEE.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 246 AM EDT SAT AUG 23 2014
HIGH IMPACT WEATHER POTENTIAL: MINIMAL
PRIMARY FORECAST CHALLENGES: DO SHOWERS MOVE INTO NORTHERN MICHIGAN?
CURRENTLY, AS WAS MENTIONED AT THE EARLIER UPDATE, RAIN SHOWERS
UPSTREAM OF THE FORECAST AREA ARE JUST SOUTH OF MQT AND SAW AND
ALONG THE 700 MB DEWPOINT DEPRESSION GRADIENT, AND IN THE LFQ OF THE
500 MB 30 KNOT JET STREAK MOVING THROUGH N WISCONSIN. MAIN FORCING
THAT IS GOING ON OVERNIGHT IS OVER FARTHER SOUTH AND WEST IN
NEBRASKA WHERE THE DEEPER SFC LOW AND 500 MB VORT AND SPEED MAXES
ARE DIGGING. THIS HAS GIVEN RISE TO THE COMPLEX OF STORMS IN THE
CENTRAL PLAINS. THE SFC LOW IN THE E COLORADO IS LINKED BY A SLOWLY
STRENGTHENING FRONT THAT STRETCHES TO THE NE THROUGH N MINNESOTA AND
UP INTO JAMES BAY TO A WEAKER SFC LOW.
TODAY...THE MODELS ARE IN GOOD AGREEMENT WITH THE
RUC/NAM12/GFS/ECMWF/LOCAL WRF4KM SHOWING THE MORNING ISOLATED
SHOWERS THAT WILL TRY TO PUSH INTO NW LOWER THIS MORNING. HOWEVER,
AS THE 500 MB RIDGE OVER THE UPPER GREAT LAKES CONTINUES TO AMPLIFY,
THE FORCING FOR THE SHOWERS WILL GET PUSHED TO THE NORTH AND WEST
THROUGH THE AFTERNOON. THE FRONT WILL ALSO MOVE TO THE NORTH AND
WEST AS THE SFC LOW IN E COLORADO MOVES OUT OVER THE CENTRAL PLAINS
AND DEEPENS. THIS WILL HELP TO FOCUS MOST OF THE RAIN INSTABILITY
AND THE DYNAMIC SUPPORT OVER THE NORTHERN PLAINS AS DEPICTED BY SPC.
TONIGHT...THIS MOVEMENT OF THE SFC LOW OUT OF THE CENTRAL PLAINS
WILL PUSH INTO NORTH DAKOTA OVERNIGHT CONTINUING TO PULL THE FOCUS
AWAY FROM THE UPPER GREAT LAKES. THIS SHOULD CONTINUE OUR RAIN FREE
STREAK (OR AT LEAST OUR MEASURABLE PRECIPITATION) THROUGH THE NIGHT.
WHILE THERE IS SOME INSTABILITY, THE LACK OF A FOCUS AND THE CAPPING
EXPECTED IN THE EVENING (BLAYER CIN 20-40 J/KG) SHOULD INHIBIT ANY
SHOWERS FROM GETTING GOING. IT DOESN`T LOOK LIKE THERE IS MUCH IN
THE WAY OF ELEVATED INSTABILITY AS THE SHOWALTER INDEX OVER N
MICHIGAN AT ITS LOWEST IS ONLY +2C.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 246 AM EDT SAT AUG 23 2014
A HIGHLY AMPLIFIED 500MB RIDGE WILL BE OVERHEAD TO START OUR SUNDAY.
AN EJECTING UPPER LOW FROM THE NORTHERN HIGH PLAINS WILL HAVE TO
CREST THIS RIDGE...AND WILL PASS WELL TO OUR NORTH MONDAY NIGHT.
THIS WILL FLATTEN OUT THE RIDGE...THOUGH IN OUR NECK OF THE WOODS
500MB HEIGHTS WILL HARDLY LOWER AT ALL. STILL...AN ASSOCIATED COLD
FRONT WILL SLOWLY GET DRAGGED INTO THE AREA MONDAY NIGHT. UNTIL THAT
HAPPENS...IT WILL BE SOMETHING OF A CHALLENGE TO GET A PRECIP THREAT
GOING IN THESE PARTS. BUT IT WON/T BE CHALLENGING TO BECOME
INCREASINGLY WARM AND HUMID.
SUNDAY...CORE OF THE 500MB RIDGE STARTS TO SLIDE DOWNSTREAM IN THE
AFTERNOON. THAT CORRESPONDS WITH A SLIGHT UPTICK IN 1000-850MB
RETURN FLOW. HOWEVER...A SHORTWAVE RIDGE ASCENDING INTO THE LARGER
RIDGE WILL HELP KEEP HEIGHTS HIGH. AT THE SAME TIME...SURFACE HIGH
PRESSURE TO OUR EAST WILL STILL EXTEND A TOUCH OF RIDGING INTO
NORTHERN MI. FROM A CONCEPTUAL MODEL STANDPOINT...IT WILL BE
DIFFICULT TO FIRE OFF CONVECTION IN THIS PATTERN UNTIL HEIGHTS ALOFT
FALL. INDEED...THE MODELS ARE NOT INCLINED TO PROG MUCH IF ANY CAPE.
00Z NAM HAS A LATE-DAY AXIS OF A FEW HUNDRED J/KG OF MUCAPE...
HUGGING THE LAKE MI COAST FROM LTL TRAV BAY SOUTH. THIS IS WHERE
LAKE BREEZE CONVERGENCE AND MOISTURE POOLING WILL BE CONCENTRATED...
THANKS TO A BACKGROUND LIGHT SE SYNOPTIC SURFACE WIND. EVEN SO...AN
82/65 PARCEL HAS ABOUT 50J/KG OF CIN TO OVERCOME...THANKS TO 700MB
TEMPS AROUND 9C.
SO WILL MAINTAIN A DRY FORECAST. CAN GENERALLY EXPECT PARTLY SUNNY
SKIES...WILL SOME BUBBLY CU AND MID/HIGH DEBRIS CLOUDS (INSTABILITY
WILL BE MUCH HIGHER W OF LAKE MI). MAX TEMPS UPPER 70S (EASTERN
UPPER...AND NE LOWER COAST)...TO LOW/MID 80S (INTERIOR SW SECTIONS).
SUN NIGHT/MONDAY...SUB-850MB FLOW MAINTAIN AN EASTERLY COMPONENT
INTO THE EVENING...BEFORE VEERING S TO EVEN SSW OVERNIGHT. THAT WILL
ALLOW A JUICIER AND POTENTIALLY UNSTABLE AIRMASS TO FINALLY MAKE
INROADS. HOWEVER...THAT WILL BE SLOW AT 1ST...WITH PERHAPS WESTERN
CHIP/MACK THE ONLY PLACE PROGGED TO SEE SOME CAPE ARRIVE BY MORNING.
THIS COULD ALLOW CONVECTION ORIGINATING IN WI A CHANCE TO GRAZE BY
THAT AREA OVERNIGHT. BUT...GIVEN THE MODELS TEND TO BE TOO QUICK TO
BREAK DOWN RIDGING AND CIN...WILL MAINTAIN A DRY FORECAST FOR SUN
NIGHT.
DEEP MOISTURE/MODERATE INSTABILITY PLUME WILL VERY SLOWLY WORK IN
FROM THE WNW MONDAY...AHEAD OF A COLD FRONT ADVANCING ACROSS WI.
HEIGHTS/TEMPS ALOFT HERE REMAIN HIGH...BUT ACTIVITY SHOULD DEVELOP
UPSTREAM IN WI AND MOVE E AND NE TOWARD WESTERN/NORTHERN
SECTIONS...ESPECIALLY LATER IN THE DAY. WILL MAINTAIN CHANCE POPS BY
AFTERNOON IN THE NW 2/3DS OF THE FORECAST AREA...INCLUDING HIGH
CHANCE (50) POPS IN WESTERN CHIP/MACK.
MIN TEMPS NEAR 60F TO THE MID 60S. MAX TEMPS NEAR 80 TO THE MID
80S...A FEW UPPER 80S POSSIBLE IN THE INTERIOR OF NORTHERN LOWER.
DEW POINTS WILL BE RISING INTO THE MID AND UPPER 60S...SO IT WILL
ALSO BE QUITE STICKY ON MONDAY.
REST OF THE FORECAST...SHAPING UP FOR A FAVORABLE MCS PATTERN
MID-WEEK. A STALLED FRONTAL ZONE (AND A WARM/HUMID AIRMASS) WILL BE
JUST TO OUR SOUTH...WITH FAST ZONAL FLOW IN THE NORTHERN LAKES.
CONSALL GRIDS ARE TRYING TO NUDGE US TOWARD LIKELY POPS IN SOME
PERIODS. AM BACKING AWAY FROM THIS THINKING GIVEN THAT IT/S
CONVECTION WE/RE TALKING ABOUT...AND PRECIP HAS UNDERPERFORMED OVER
THE LAST WEEK OR SO. TEMPS WILL BE DRIFTING BACK TOWARD OR A BIT
UNDER CLIMO BY LATE IN THE WORK WEEK...THOUGH PROBABLY NOT AS COOL
AS THE GFS/MEX GUIDANCE ADVERTISES...AS THE ECMWF IS SLOWER AND LESS
AMPLIFIED WITH THE UPPER TROF THAT PROGRESSES INTO THE PLAINS STATES
MID/LATE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 645 AM EDT SAT AUG 23 2014
FOG TO BURN OFF THIS MORNING...THEN VFR THRU THIS EVENING. SOME
FOG AGAIN LATE TONIGHT.
HUMID AIRMASS WILL REMAIN IN PLACE THIS WEEKEND. WITH LIGHT WINDS
AT NIGHT...FOG HAS BEEN AN ISSUE...AND THAT WILL CONTINUE. PLN/APN
GETTING THE WORST OF IT THIS MORNING...LIFR AT TIMES. THAT WILL
ONLY LAST 1-2 HOURS PAST 12Z AT MOST. THEN VFR. LIFR FOG IS AGAIN
LIKELY AT APN/PLN LATE TONIGHT...HAVE ADDED MVFR CONDITIONS TO MBL
LATE AS WELL.
LIGHT WINDS.
&&
.MARINE...
ISSUED AT 246 AM EDT SAT AUG 23 2014
OVER THE NEXT 48 HOURS, THE WINDS WILL SLOWLY INCREASE AND VEER
FROM THE EAST TO THE SOUTH LOW PRESSURE NEAR COLORADO DEEPENS AND
MOVES INTO NORTH DAKOTA. SO TODAY THROUGH SUNDAY NIGHT, WILL
EXPECT THAT WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT
CONDITIONS.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...ADAM
SYNOPSIS...JZ
SHORT TERM...JL
LONG TERM...JZ
AVIATION...JZ
MARINE...JL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1230 PM CDT SAT AUG 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT AUG 23 2014
WE HAVE BEEN WATCHING AN IMPRESSIVE THUNDERSTORM COMPLEX RACE NORTH
ACROSS NEBRASKA OVERNIGHT IN ASSOCIATION WITH A SHORTWAVE ROTATING
NNE AROUND THE BASE OF A DEEP TROUGH CENTERED OVER IDAHO.
HOWEVER...DO NOT GET TOO EXCITED ABOUT THE PROSPECTS ABOUT ANYONE IN
THE MPX CWA SEEING MUCH OF THIS PRECIP TODAY...AS THIS WAA PRECIP
LOOKS TO LARGELY GO AROUND THE MPX CWA. MOST CAMS SHOW TWO
CONCENTRATED AREAS THIS MORNING HEADING EAST ACROSS IOWA...WITH THE
OTHER BATCH OF WIDESPREAD THUNDERSTORMS TO HEAD NORTH ACROSS THE
DAKOTAS. THE IOWA AREA IS IN RESPONSE TO AIR GETTING FORCED UP OVER
THE REMNANTS OF A COLD FRONT...WHICH AT 3 AM WAS LOCATED JUST SOUTH
OF OMAHA TO THE QUAD CITIES...WHICH IS MORE OR LESS THE AXIS WHERE
THE HRRR HAS A SWATH OF HIGHER QPF FALLING. THE DAKOTAS BULLSEYE IS
RESPONSE THE NOSE OF A 40 KT ESE ORIENTED LLJ THAT WILL BE WORKING
NORTH IN CONJUNCTION WITH THE STRONG SHORTWAVE CURRENTLY OVER
CENTRAL NEB. WITH THAT SAID...ACTIVITY OUT THERE NOW LOOKS LIKE IT
SHOULD HAVE ENOUGH MOMENTUM TO AT LEAST SNEAK UP TO AREAS SOUTH/WEST
OF THE MN RIVER. OTHERWISE...FOR MUCH OF THE MPX AREA...THE BAND OF
STORMS WE SEE COMING NORTH NOW WILL NOT DO MUCH MORE THAN BRING A
BAND OF ALTOCU THROUGH THE AREA.
FOR THIS AFTERNOON...ATTENTION TURNS TO THE SEVERE POTENTIAL OUT IN
WRN MN. BY THE AFTERNOON...THE BROAD SFC CYCLONE CURRENTLY SPLAYED
OUT ACROSS THE CENTRAL HIGH PLAINS WILL HAVE CONSOLIDATED INTO A
1000 MB LOW NEAR THE CENTRAL ND/SD BORDER. THIS WILL HELP PULL THE
FRONT IN IOWA BACK NORTH AS A WARM...WITH IT PUSHING INTO SW MN
AFTER 00Z. WILL HAVE TO WAIT A WHILE FOR SFC BASED CONVECTION TO
FIRE GIVEN EXTENT OF RAIN/CLOUD COVER EXPECTED ACROSS THE DAKOTAS
THIS MORNING..BUT EXPECT ENOUGH HEATING TO OCCUR THIS AFTERNOON TO
ALLOW FOR STORMS TO DEVELOP NEAR THE SURGING WARM FRONT ALONG THE
COTEAU IN SE SODAK AROUND 21Z...AS BOTH THE NMM/ARW SHOW. THIS
ACTIVITY SHOULD THEN TRACK NNE...TOWARD WEST CENTRAL AND NORTHWEST
MN DURING THE EVENING...AND IT IS THIS POTENTIAL ACTIVITY THAT
GIVES US THE SLIGHT RISK FOR TODAY FROM THE SPC. CERTAINLY
INSTABILITY AND SHEAR ARE ADEQUATE TO SUPPORT SURFACE BASED
SUPERCELLS AND THEREFOR ALL MODES OF SEVERE WEATHER. HOWEVER...FOR
AS FAR EAST AS MN...SHEAR VECTORS WILL BE MORE PARALLEL THAN
PERPENDICULAR TO THE FORCING...WHICH WOULD FAVOR THE CONGEALING OF
ACTIVITY INTO CLUSTERS/LINES...WHICH IS WHAT IS SEEN WITH NMM/ARW
REFLECTIVITY FORECASTS. THIS WOULD FAVOR THE HIGHEST TORNADO THREAT
BEING ACROSS THE DAKOTAS...WHERE STORMS ARE MORE LIKELY TO BE
DISCRETE...WITH WRN MN DEALING MORE WITH A POTENTIAL WIND/HAIL
THREAT.
FROM THE FLOOD TREAT...PWATS WILL INCREASE BACK TO AROUND 1.75
INCHES...SO CERTAINLY WILL SEE HEAVY RAIN WITH THIS ACTIVITY.
HOWEVER...CURRENT EXPECTATIONS ARE THAT ACTIVITY WILL BE PROGRESSIVE
ENOUGH TO KEEP ANY CONCENTRATED SWATHS OF HIGH QPF DOWN IN THE 1-2
INCH RANGE AS OPPOSED TO BEING UP IN THE 3-6 INCH RANGE LIKE WE WERE
SEEING LAST WEEK.
FOR TONIGHT...BEST UPPER FORCING WILL BE STAYING NW OF THE MPX
CWA...SO ACTIVITY THAT MOVES INTO WRN MN WILL HEAD FOR NW/NC MN...SO
CUT BACK CONSIDERABLY ON POPS...KEEPING THE ERN 2/3RDS OR SO OF THE
CWA DRY. MAY STILL BE TOO FAR EAST WITH POPS TONIGHT...BUT WE SHOULD
SEE SOMEWHAT OF AN EWRD PUSH WITH ACTIVITY TONIGHT AS COLD POOLS GET
GENERATED. EVEN IF IT DOES NOT RAIN...IT WILL BE A MUGGY NIGHT...AS
LOWER 70 DEWPS COME UP WITH THE WARM FRONT. WILL LIKELY MAKE IT
TOUGH FOR MUCH OF THE MN CWA TO DIP BELOW 70 SUNDAY MORNING...WHICH
WILL HAVE IMPLICATIONS ON THE POTENTIAL NEED FOR ANY HEAT HEADLINES
SUNDAY. NOT WORRIED ABOUT FOG TONIGHT EITHER...AS GRADIENT WILL
REMAIN STRONG THROUGH THE NIGHT...SO WILL BE ANOTHER NIGHT LIKE
TONIGHT WHERE WE JUST WATCH ANY STRATUS THAT SURVIVES THE DAY TODAY
EXPAND AGAIN OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT AUG 23 2014
THERE IS DEFINITELY SOME SPREAD IN THE MODEL GUIDANCE AS WE HEAD
THROUGH THE LATTER PORTION OF THE FORECAST... BUT THE GENERAL
SCENARIO SUGGESTS A TRANSITION FOR WESTERN RIDGE/EASTERN TROUGH TO
MORE OF A ZONAL PATTERN BY THE END OF THE WEEK. THIS SHOULD ALLOW
FOR TEMPERATURES TO TREND FROM ABOVE NORMAL TO NEAR NORMAL AS THE
WEEK UNFOLDS... WITH PCPN CHANCES BEING A BIT TOUGH TO PIN DOWN
DEPENDING UPON WHERE THE MAIN BAROCLINIC ZONE SETS UP. GIVEN THE
SPREAD IN DETERMINISTIC AND ENSEMBLE GUIDANCE... A CONSENSUS
APPROACH IS THE MOST SENSIBLE COURSE OF ACTION... SO STUCK CLOSE
TO A MULTI-MODEL BLEND.
THE MAIN FORECAST ISSUES LOOK TO BE THE POTENTIAL FOR EXCESSIVE
HEAT/HUMIDITY SUNDAY... THEN THE POSSIBILITY OF SIGNIFICANT PCPN
OVER THE SOUTHERN PORTION OF THE AREA LATE MONDAY THROUGH
WEDNESDAY AS THE FRONTAL BOUNDARY HANGS UP SOMEWHERE NEAR THE
MINNESOTA/IOWA BORDER. SUNDAY STILL LOOKS TO HAVE THE POTENTIAL
FOR VERY WARM TEMPERATURES ACROSS THE AREA... ALONG WITH HIGH
DEWPOINTS. AT THIS POINT... APPARENT TEMPERATURE FORECASTS PEAK
AROUND 100 OVER A PORTION OF THE AREA SUNDAY AFTERNOON WITH
FORECAST HIGHS IN THE LOW 90S AND DEWPOINTS NEAR 70. WET BULB
GLOBE TEMPERATURES JUMP INTO THE LOWER TO MIDDLE 80S AS WELL...
ALSO INDICATING THE POTENTIAL FOR HEAT RELATED ISSUES FOR PEOPLE
WHO MAY BE OUTDOORS ON SUNDAY. THERE WILL CERTAINLY BE A
SIGNIFICANT NUMBER OF PEOPLE OUTDOORS IN THE METRO AREA ON SUNDAY
WITH THE GREAT MINNESOTA GET TOGETHER IN FULL SWING... SO THE
POSSIBILITY OF EXCESSIVE HEAT/HUMIDITY WILL NEED TO BE MONITORED
IN SUBSEQUENT FORECASTS. AT THIS POINT... THERE IS STILL SOME
UNCERTAINTY IN CLOUD COVER AND WHETHER WE/LL MIX AS WELL AS SOME
GUIDANCE SUGGESTS AND/OR SEE MORE LOW LEVEL EVAPORATIVE COOLING
THAN ANTICIPATED. SO... WILL HIGHLIGHT THE POSSIBILITY IN THE
HAZARDOUS WEATHER OUTLOOK AND OTHER SERVICES... BUT HOLD OFF ON
ANY ACTUAL HEADLINES AT THIS POINT. PCPN CHANCES ON SUNDAY LOOK TO
BE CONFINED TO THE WESTERN/NORTHERN PORTION OF THE AREA UNTIL
LATE AFTERNOON AND/OR EVENING WHEN THE COLD FRONT FINALLY STARTS
TO WORK ITS WAY EAST ACROSS THE AREA. AT THAT POINT... THE MAIN
LARGE SCALE FORCING WILL BE TO OUR NORTH... SO PCPN MAY BE
SCATTERED IN NATURE WITH MORE WIDESPREAD ACTIVITY WITH THE
SHORTWAVE AND TRIPLE-POINT TO OUR NORTH AND THE SECONDARY WARM
ADVECTION/INSTABILITY NOSE TO OUR SOUTH. DEEP LAYER SHEAR WILL BE
BEST TO OUR NORTH... SO ANY SEVERE POTENTIAL LOOKS TO BE CAPE-
DRIVEN WITH MAINLY MULTI-CELL WIND/HAIL STORMS BEING THE CONCERN.
CHANCES FOR PCPN WILL PUSH EAST SUNDAY NIGHT WITH THE FRONT...
THEN WE/LL SEE HIGH PRESSURE BUILD OVER MUCH OF THE AREA.
HOWEVER... THE FRONTAL BOUNDARY LOOKS TO HANG UP TO OUR SOUTH/EAST
MONDAY INTO WEDNESDAY... NECESSITATING THE INCLUSION OF POPS OVER
MUCH OF THE AREA DURING THAT TIME FRAME... WITH BETTER CHANCES
SOUTH AND LOW CHANCES NORTH. THE FAR SOUTHERN PORTION OF THE AREA
HAS SOME POTENTIAL TO SEE SIGNIFICANT RAINFALL OVER THAT PERIOD OF
TIME... BUT MUCH WILL DEPEND ON WHERE SUCCESSIVE ROUNDS OF
SHRA/TSRA DECIDE TO TRACK... AND IT IS TOO EARLY TO GET A GOOD
HANDLE ON THAT EVOLUTION. WE SHOULD SEE HIGH PRESSURE...
SUBSIDENCE... AND DRIER AIR WORK INTO THE ENTIRE AREA FROM THE
NORTHWEST WEDNESDAY NIGHT THROUGH THE REMAINDER OF THE FORECAST
PERIOD... WITH DRY WEATHER PREDOMINATING. HOWEVER... THE 00Z ECMWF
IS A BIT SLOWER IN SHOWING THIS EVOLUTION IN COMPARISON TO ITS
PREVIOUS RUNS OR THE 00Z GFS... SO WE/LL NEED TO SEE HOW THINGS
EVOLVE IN SUBSEQUENT FORECASTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1212 PM CDT SAT AUG 23 2014
NORTHERN EDGE OF DISSIPATING MCS OVER EASTERN IOWA CLIPPED KMSP
AROUND NOON. LIGHT -SHRA INDICATED. THIS CONTINUES TO MOVE EAST
AND IF MAY AFFECT KEAU EARLY. INCLUDED VCSH FOR THAT. COMPLICATED
SCENARIO DEVELOPING WITH THE UPPER TROUGH MOVING THROUGH THE
DAKOTAS. HIRES MODELS ARE PICKING UP ON SOME ACCAS LIFITNG OUT OF
SOUTHEAST SODAK. THEY DEVELOP SOME ISOLD TSRA INTO SW MN DURING
THE AFTERNOON...AND DISSIPATE LATE AFTERNOON INTO SC MN. WONT
MENTION THIS ACTIVITY AT TAF SITE FOR NOW. LOWER IFR CLOUDS REMAIN
LOCKED OVER CENTRAL MN WITH SOME EROSION NOTED INTO SC MN. THIS
MAY WORK N-NE INTO THE AFTERNOON IN THE WAKE OF THE IOWA MCS. WILL
TREND VFR THROUGH ABOUT 00Z MOST AREAS. EXPECT THUNDER TO DEVELOP
AROUND 00Z IN EASTERN SODAK AND LIT NORTHEAST OVER WESTERN AND
CENTRAL MN THROUGH THE NIGHT. HEAVY RAIN/POSSIBLE SEVERE INTO FAR
WESTERN MN THROUGH ABOUT 06Z OR SO. WILL DROP CIGS AGAIN TO IFR
OVERNIGHT AS WARM FRONT LIFTS OVER THE AREA. WILL MENTION MAINLY
3-5SM BR WITH IFR CIGS. EXPECT SLOW IMPROVEMENT AGAIN INTO
SATURDAY MORNING...SIMILAR TO PREVIOUS FORECAST TREND. INCREASING
GRADIENT AHEAD OF FRONT SHOULD YIELD SOME STRONG SE-S SOUTH WINDS
WITH FROPA SATURDAY.
KMSP...-SHRA/SPINKLES EXITING KMSP NOW. NEXT THREAT MOVES IN AFTER
05Z WITH A PROB30 FOR THUNDER INDICATED THROUGH 08Z. CIGS EXPECTED
TO DROP OFF TO IFR LATE WITH IMPROVING CONDITIONS TO MVFR BY
MIDE/LATE SUNDAY MORNING. EAST TO SOUTHEAST WINDS AHEAD OF WARM
FRONT...WITH WINDS BECOMING MORE SOUTHERLY BY LATE SUNDAY MORNING
OR EARLY SUNDAY AFTERNOON. SPEEDS AREA EXPECTED TO REMAIN AROUND
10KTS INTO TONIGHT...INCREASING TO 10-14KTS SUNDAY MORNING.
/OUTLOOK FOR KMSP/
SUN NIGHT...VFR. CHANCE MVFR/TSRA. S WINDS 10-14KTS BCMG W 5-10
KTS.
MON...VFR. WINDS W 5-10 KTS.
TUE...SHRA/TSRA AND MVFR LIKELY BY AFTERNOON. WINDS NE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...
AVIATION...DWE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
612 AM CDT SAT AUG 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT AUG 23 2014
WE HAVE BEEN WATCHING AN IMPRESSIVE THUNDERSTORM COMPLEX RACE NORTH
ACROSS NEBRASKA OVERNIGHT IN ASSOCIATION WITH A SHORTWAVE ROTATING
NNE AROUND THE BASE OF A DEEP TROUGH CENTERED OVER IDAHO.
HOWEVER...DO NOT GET TOO EXCITED ABOUT THE PROSPECTS ABOUT ANYONE IN
THE MPX CWA SEEING MUCH OF THIS PRECIP TODAY...AS THIS WAA PRECIP
LOOKS TO LARGELY GO AROUND THE MPX CWA. MOST CAMS SHOW TWO
CONCENTRATED AREAS THIS MORNING HEADING EAST ACROSS IOWA...WITH THE
OTHER BATCH OF WIDESPREAD THUNDERSTORMS TO HEAD NORTH ACROSS THE
DAKOTAS. THE IOWA AREA IS IN RESPONSE TO AIR GETTING FORCED UP OVER
THE REMNANTS OF A COLD FRONT...WHICH AT 3 AM WAS LOCATED JUST SOUTH
OF OMAHA TO THE QUAD CITIES...WHICH IS MORE OR LESS THE AXIS WHERE
THE HRRR HAS A SWATH OF HIGHER QPF FALLING. THE DAKOTAS BULLSEYE IS
RESPONSE THE NOSE OF A 40 KT ESE ORIENTED LLJ THAT WILL BE WORKING
NORTH IN CONJUNCTION WITH THE STRONG SHORTWAVE CURRENTLY OVER
CENTRAL NEB. WITH THAT SAID...ACTIVITY OUT THERE NOW LOOKS LIKE IT
SHOULD HAVE ENOUGH MOMENTUM TO AT LEAST SNEAK UP TO AREAS SOUTH/WEST
OF THE MN RIVER. OTHERWISE...FOR MUCH OF THE MPX AREA...THE BAND OF
STORMS WE SEE COMING NORTH NOW WILL NOT DO MUCH MORE THAN BRING A
BAND OF ALTOCU THROUGH THE AREA.
FOR THIS AFTERNOON...ATTENTION TURNS TO THE SEVERE POTENTIAL OUT IN
WRN MN. BY THE AFTERNOON...THE BROAD SFC CYCLONE CURRENTLY SPLAYED
OUT ACROSS THE CENTRAL HIGH PLAINS WILL HAVE CONSOLIDATED INTO A
1000 MB LOW NEAR THE CENTRAL ND/SD BORDER. THIS WILL HELP PULL THE
FRONT IN IOWA BACK NORTH AS A WARM...WITH IT PUSHING INTO SW MN
AFTER 00Z. WILL HAVE TO WAIT A WHILE FOR SFC BASED CONVECTION TO
FIRE GIVEN EXTENT OF RAIN/CLOUD COVER EXPECTED ACROSS THE DAKOTAS
THIS MORNING..BUT EXPECT ENOUGH HEATING TO OCCUR THIS AFTERNOON TO
ALLOW FOR STORMS TO DEVELOP NEAR THE SURGING WARM FRONT ALONG THE
COTEAU IN SE SODAK AROUND 21Z...AS BOTH THE NMM/ARW SHOW. THIS
ACTIVITY SHOULD THEN TRACK NNE...TOWARD WEST CENTRAL AND NORTHWEST
MN DURING THE EVENING...AND IT IS THIS POTENTIAL ACTIVITY THAT
GIVES US THE SLIGHT RISK FOR TODAY FROM THE SPC. CERTAINLY
INSTABILITY AND SHEAR ARE ADEQUATE TO SUPPORT SURFACE BASED
SUPERCELLS AND THEREFOR ALL MODES OF SEVERE WEATHER. HOWEVER...FOR
AS FAR EAST AS MN...SHEAR VECTORS WILL BE MORE PARALLEL THAN
PERPENDICULAR TO THE FORCING...WHICH WOULD FAVOR THE CONGEALING OF
ACTIVITY INTO CLUSTERS/LINES...WHICH IS WHAT IS SEEN WITH NMM/ARW
REFLECTIVITY FORECASTS. THIS WOULD FAVOR THE HIGHEST TORNADO THREAT
BEING ACROSS THE DAKOTAS...WHERE STORMS ARE MORE LIKELY TO BE
DISCRETE...WITH WRN MN DEALING MORE WITH A POTENTIAL WIND/HAIL
THREAT.
FROM THE FLOOD TREAT...PWATS WILL INCREASE BACK TO AROUND 1.75
INCHES...SO CERTAINLY WILL SEE HEAVY RAIN WITH THIS ACTIVITY.
HOWEVER...CURRENT EXPECTATIONS ARE THAT ACTIVITY WILL BE PROGRESSIVE
ENOUGH TO KEEP ANY CONCENTRATED SWATHS OF HIGH QPF DOWN IN THE 1-2
INCH RANGE AS OPPOSED TO BEING UP IN THE 3-6 INCH RANGE LIKE WE WERE
SEEING LAST WEEK.
FOR TONIGHT...BEST UPPER FORCING WILL BE STAYING NW OF THE MPX
CWA...SO ACTIVITY THAT MOVES INTO WRN MN WILL HEAD FOR NW/NC MN...SO
CUT BACK CONSIDERABLY ON POPS...KEEPING THE ERN 2/3RDS OR SO OF THE
CWA DRY. MAY STILL BE TOO FAR EAST WITH POPS TONIGHT...BUT WE SHOULD
SEE SOMEWHAT OF AN EWRD PUSH WITH ACTIVITY TONIGHT AS COLD POOLS GET
GENERATED. EVEN IF IT DOES NOT RAIN...IT WILL BE A MUGGY NIGHT...AS
LOWER 70 DEWPS COME UP WITH THE WARM FRONT. WILL LIKELY MAKE IT
TOUGH FOR MUCH OF THE MN CWA TO DIP BELOW 70 SUNDAY MORNING...WHICH
WILL HAVE IMPLICATIONS ON THE POTENTIAL NEED FOR ANY HEAT HEADLINES
SUNDAY. NOT WORRIED ABOUT FOG TONIGHT EITHER...AS GRADIENT WILL
REMAIN STRONG THROUGH THE NIGHT...SO WILL BE ANOTHER NIGHT LIKE
TONIGHT WHERE WE JUST WATCH ANY STRATUS THAT SURVIVES THE DAY TODAY
EXPAND AGAIN OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT AUG 23 2014
THERE IS DEFINITELY SOME SPREAD IN THE MODEL GUIDANCE AS WE HEAD
THROUGH THE LATTER PORTION OF THE FORECAST... BUT THE GENERAL
SCENARIO SUGGESTS A TRANSITION FOR WESTERN RIDGE/EASTERN TROUGH TO
MORE OF A ZONAL PATTERN BY THE END OF THE WEEK. THIS SHOULD ALLOW
FOR TEMPERATURES TO TREND FROM ABOVE NORMAL TO NEAR NORMAL AS THE
WEEK UNFOLDS... WITH PCPN CHANCES BEING A BIT TOUGH TO PIN DOWN
DEPENDING UPON WHERE THE MAIN BAROCLINIC ZONE SETS UP. GIVEN THE
SPREAD IN DETERMINISTIC AND ENSEMBLE GUIDANCE... A CONSENSUS
APPROACH IS THE MOST SENSIBLE COURSE OF ACTION... SO STUCK CLOSE
TO A MULTI-MODEL BLEND.
THE MAIN FORECAST ISSUES LOOK TO BE THE POTENTIAL FOR EXCESSIVE
HEAT/HUMIDITY SUNDAY... THEN THE POSSIBILITY OF SIGNIFICANT PCPN
OVER THE SOUTHERN PORTION OF THE AREA LATE MONDAY THROUGH
WEDNESDAY AS THE FRONTAL BOUNDARY HANGS UP SOMEWHERE NEAR THE
MINNESOTA/IOWA BORDER. SUNDAY STILL LOOKS TO HAVE THE POTENTIAL
FOR VERY WARM TEMPERATURES ACROSS THE AREA... ALONG WITH HIGH
DEWPOINTS. AT THIS POINT... APPARENT TEMPERATURE FORECASTS PEAK
AROUND 100 OVER A PORTION OF THE AREA SUNDAY AFTERNOON WITH
FORECAST HIGHS IN THE LOW 90S AND DEWPOINTS NEAR 70. WET BULB
GLOBE TEMPERATURES JUMP INTO THE LOWER TO MIDDLE 80S AS WELL...
ALSO INDICATING THE POTENTIAL FOR HEAT RELATED ISSUES FOR PEOPLE
WHO MAY BE OUTDOORS ON SUNDAY. THERE WILL CERTAINLY BE A
SIGNIFICANT NUMBER OF PEOPLE OUTDOORS IN THE METRO AREA ON SUNDAY
WITH THE GREAT MINNESOTA GET TOGETHER IN FULL SWING... SO THE
POSSIBILITY OF EXCESSIVE HEAT/HUMIDITY WILL NEED TO BE MONITORED
IN SUBSEQUENT FORECASTS. AT THIS POINT... THERE IS STILL SOME
UNCERTAINTY IN CLOUD COVER AND WHETHER WE/LL MIX AS WELL AS SOME
GUIDANCE SUGGESTS AND/OR SEE MORE LOW LEVEL EVAPORATIVE COOLING
THAN ANTICIPATED. SO... WILL HIGHLIGHT THE POSSIBILITY IN THE
HAZARDOUS WEATHER OUTLOOK AND OTHER SERVICES... BUT HOLD OFF ON
ANY ACTUAL HEADLINES AT THIS POINT. PCPN CHANCES ON SUNDAY LOOK TO
BE CONFINED TO THE WESTERN/NORTHERN PORTION OF THE AREA UNTIL
LATE AFTERNOON AND/OR EVENING WHEN THE COLD FRONT FINALLY STARTS
TO WORK ITS WAY EAST ACROSS THE AREA. AT THAT POINT... THE MAIN
LARGE SCALE FORCING WILL BE TO OUR NORTH... SO PCPN MAY BE
SCATTERED IN NATURE WITH MORE WIDESPREAD ACTIVITY WITH THE
SHORTWAVE AND TRIPLE-POINT TO OUR NORTH AND THE SECONDARY WARM
ADVECTION/INSTABILITY NOSE TO OUR SOUTH. DEEP LAYER SHEAR WILL BE
BEST TO OUR NORTH... SO ANY SEVERE POTENTIAL LOOKS TO BE CAPE-
DRIVEN WITH MAINLY MULTI-CELL WIND/HAIL STORMS BEING THE CONCERN.
CHANCES FOR PCPN WILL PUSH EAST SUNDAY NIGHT WITH THE FRONT...
THEN WE/LL SEE HIGH PRESSURE BUILD OVER MUCH OF THE AREA.
HOWEVER... THE FRONTAL BOUNDARY LOOKS TO HANG UP TO OUR SOUTH/EAST
MONDAY INTO WEDNESDAY... NECESSITATING THE INCLUSION OF POPS OVER
MUCH OF THE AREA DURING THAT TIME FRAME... WITH BETTER CHANCES
SOUTH AND LOW CHANCES NORTH. THE FAR SOUTHERN PORTION OF THE AREA
HAS SOME POTENTIAL TO SEE SIGNIFICANT RAINFALL OVER THAT PERIOD OF
TIME... BUT MUCH WILL DEPEND ON WHERE SUCCESSIVE ROUNDS OF
SHRA/TSRA DECIDE TO TRACK... AND IT IS TOO EARLY TO GET A GOOD
HANDLE ON THAT EVOLUTION. WE SHOULD SEE HIGH PRESSURE...
SUBSIDENCE... AND DRIER AIR WORK INTO THE ENTIRE AREA FROM THE
NORTHWEST WEDNESDAY NIGHT THROUGH THE REMAINDER OF THE FORECAST
PERIOD... WITH DRY WEATHER PREDOMINATING. HOWEVER... THE 00Z ECMWF
IS A BIT SLOWER IN SHOWING THIS EVOLUTION IN COMPARISON TO ITS
PREVIOUS RUNS OR THE 00Z GFS... SO WE/LL NEED TO SEE HOW THINGS
EVOLVE IN SUBSEQUENT FORECASTS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 544 AM CDT SAT AUG 23 2014
WINDS HAVE STAYED UP ENOUGH THROUGH THE NIGHT TO KEEP THIS
MORNINGS ISSUE AS ONE OF STRATUS. GIVEN THE STRONGER WINDS...WE
WILL SEE THESE CLOUDS CLEAR OUT MORE QUICKLY THAN WE DID
YESTERDAY...BUT WILL STILL BE STUCK WITH IFR/MVFR CIGS THROUGH
MUCH OF THE MORNING. AREA OF TSRA ENTERING SW MN WILL STRUGGLE TO
MAKE IT MUCH FARTHER INTO THE STATE AS THE LLJ SLIDES MORE EAST
ACROSS IOWA...KEEPING ACTIVITY TODAY MAINLY ALONG I-90...WITH A
SECOND BATCH REMAINING OUT IN THE DAKOTAS. FOR THIS
AFTERNOON...EXPECT STORMS TO DEVELOP ACROSS ERN SODAK AND HEAD NE
TOWARD WEST CENTRAL MN. AXN LOOKS TO BE MOST SUSCEPTIBLE TO TSRA
THIS EVENING...WITH BEST CHANCES REMAINING NORTH OF RWF AND WEST
OF ALL OTHER TERMINALS. WILL ALSO HAVE A WARM FROM WORKING ACROSS
SW MN OVERNIGHT...WITH THE THREAT FOR MORE IFR/LIFR STRATUS
EXISTING AHEAD OF THIS BOUNDARY...WITH MAINLY MVFR HZ/BR IN THE
WARM SECTOR. AT THIS POINT...ONLY RWF LOOKS TO DEFINITELY SEE THE
WARM SECTOR...WHILE THE WI TERMINALS WILL REMAIN OUT AHEAD OF IT.
AXN/STC/MSP WILL HAVE THE BOUNDARY NEARBY BY THE END OF THE
NIGHT...BUT GIVEN THE DEGREE OF LOW LEVEL MOISTURE
AROUND...DECIDED TO GO WITH THE IDEA OF ANOTHER ROUND OF LOW
STRATUS TO START SUNDAY.
KMSP...DESPITE WHAT RADAR LOOKS LIKE TO THE SW...CONFIDENT THAT
MSP WILL SEE NOTHING MORE THAN SOME SPRINKLES THIS MORNING...AS
THIS ACTIVITY IS STARTING TO FAVOR IOWA BASED ON CLOUD TOP
TEMPERATURES WARMING OVER MN AND REMAINING COLD OVER IA. STRATUS
WILL BE EASIER TO CLEAR OUT TODAY GIVEN THE STRONGER WINDS.
TONIGHT...GIVEN WHERE FORCING IS GOING...CONFIDENT IN ANY TSRA
ACTIVITY REMAINING NW OF MSP. WILL BE VERY MOIST AGAIN...AND GIVEN
WHAT WE HAVE SEEN THE LAST FEW MORNINGS WITH STRATUS...DECIDED TO
GO WITH THE TREND OF LOW STRATUS RETURNING TO START OF SUNDAY.
HOWEVER...SUNDAY SHOULD SEE IT CLEAR OUT EVEN FASTER...AS A WARM
FRONT LOOKS TO QUICKLY CLEAR THE FIELD IN THE MORNING...WITH A
RATHER TOASTY WARM SECTOR MOVING IN IN ITS WAKE.
/OUTLOOK FOR KMSP/
SUN NIGHT...VFR. CHANCE MVFR/TSRA. WINDS BCMG W 5-10 KTS.
MON...VFR. WINDS W 5-10 KTS.
TUE...SHRA/TSRA AND MVFR LIKELY BY AFTERNOON. WINDS NE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
354 AM CDT SAT AUG 23 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT SAT AUG 23 2014
WE HAVE BEEN WATCHING AN IMPRESSIVE THUNDERSTORM COMPLEX RACE NORTH
ACROSS NEBRASKA OVERNIGHT IN ASSOCIATION WITH A SHORTWAVE ROTATING
NNE AROUND THE BASE OF A DEEP TROUGH CENTERED OVER IDAHO.
HOWEVER...DO NOT GET TOO EXCITED ABOUT THE PROSPECTS ABOUT ANYONE IN
THE MPX CWA SEEING MUCH OF THIS PRECIP TODAY...AS THIS WAA PRECIP
LOOKS TO LARGELY GO AROUND THE MPX CWA. MOST CAMS SHOW TWO
CONCENTRATED AREAS THIS MORNING HEADING EAST ACROSS IOWA...WITH THE
OTHER BATCH OF WIDESPREAD THUNDERSTORMS TO HEAD NORTH ACROSS THE
DAKOTAS. THE IOWA AREA IS IN RESPONSE TO AIR GETTING FORCED UP OVER
THE REMNANTS OF A COLD FRONT...WHICH AT 3 AM WAS LOCATED JUST SOUTH
OF OMAHA TO THE QUAD CITIES...WHICH IS MORE OR LESS THE AXIS WHERE
THE HRRR HAS A SWATH OF HIGHER QPF FALLING. THE DAKOTAS BULLSEYE IS
RESPONSE THE NOSE OF A 40 KT ESE ORIENTED LLJ THAT WILL BE WORKING
NORTH IN CONJUNCTION WITH THE STRONG SHORTWAVE CURRENTLY OVER
CENTRAL NEB. WITH THAT SAID...ACTIVITY OUT THERE NOW LOOKS LIKE IT
SHOULD HAVE ENOUGH MOMENTUM TO AT LEAST SNEAK UP TO AREAS SOUTH/WEST
OF THE MN RIVER. OTHERWISE...FOR MUCH OF THE MPX AREA...THE BAND OF
STORMS WE SEE COMING NORTH NOW WILL NOT DO MUCH MORE THAN BRING A
BAND OF ALTOCU THROUGH THE AREA.
FOR THIS AFTERNOON...ATTENTION TURNS TO THE SEVERE POTENTIAL OUT IN
WRN MN. BY THE AFTERNOON...THE BROAD SFC CYCLONE CURRENTLY SPLAYED
OUT ACROSS THE CENTRAL HIGH PLAINS WILL HAVE CONSOLIDATED INTO A
1000 MB LOW NEAR THE CENTRAL ND/SD BORDER. THIS WILL HELP PULL THE
FRONT IN IOWA BACK NORTH AS A WARM...WITH IT PUSHING INTO SW MN
AFTER 00Z. WILL HAVE TO WAIT A WHILE FOR SFC BASED CONVECTION TO
FIRE GIVEN EXTENT OF RAIN/CLOUD COVER EXPECTED ACROSS THE DAKOTAS
THIS MORNING..BUT EXPECT ENOUGH HEATING TO OCCUR THIS AFTERNOON TO
ALLOW FOR STORMS TO DEVELOP NEAR THE SURGING WARM FRONT ALONG THE
COTEAU IN SE SODAK AROUND 21Z...AS BOTH THE NMM/ARW SHOW. THIS
ACTIVITY SHOULD THEN TRACK NNE...TOWARD WEST CENTRAL AND NORTHWEST
MN DURING THE EVENING...AND IT IS THIS POTENTIAL ACTIVITY THAT
GIVES US THE SLIGHT RISK FOR TODAY FROM THE SPC. CERTAINLY
INSTABILITY AND SHEAR ARE ADEQUATE TO SUPPORT SURFACE BASED
SUPERCELLS AND THEREFOR ALL MODES OF SEVERE WEATHER. HOWEVER...FOR
AS FAR EAST AS MN...SHEAR VECTORS WILL BE MORE PARALLEL THAN
PERPENDICULAR TO THE FORCING...WHICH WOULD FAVOR THE CONGEALING OF
ACTIVITY INTO CLUSTERS/LINES...WHICH IS WHAT IS SEEN WITH NMM/ARW
REFLECTIVITY FORECASTS. THIS WOULD FAVOR THE HIGHEST TORNADO THREAT
BEING ACROSS THE DAKOTAS...WHERE STORMS ARE MORE LIKELY TO BE
DISCRETE...WITH WRN MN DEALING MORE WITH A POTENTIAL WIND/HAIL
THREAT.
FROM THE FLOOD TREAT...PWATS WILL INCREASE BACK TO AROUND 1.75
INCHES...SO CERTAINLY WILL SEE HEAVY RAIN WITH THIS ACTIVITY.
HOWEVER...CURRENT EXPECTATIONS ARE THAT ACTIVITY WILL BE PROGRESSIVE
ENOUGH TO KEEP ANY CONCENTRATED SWATHS OF HIGH QPF DOWN IN THE 1-2
INCH RANGE AS OPPOSED TO BEING UP IN THE 3-6 INCH RANGE LIKE WE WERE
SEEING LAST WEEK.
FOR TONIGHT...BEST UPPER FORCING WILL BE STAYING NW OF THE MPX
CWA...SO ACTIVITY THAT MOVES INTO WRN MN WILL HEAD FOR NW/NC MN...SO
CUT BACK CONSIDERABLY ON POPS...KEEPING THE ERN 2/3RDS OR SO OF THE
CWA DRY. MAY STILL BE TOO FAR EAST WITH POPS TONIGHT...BUT WE SHOULD
SEE SOMEWHAT OF AN EWRD PUSH WITH ACTIVITY TONIGHT AS COLD POOLS GET
GENERATED. EVEN IF IT DOES NOT RAIN...IT WILL BE A MUGGY NIGHT...AS
LOWER 70 DEWPS COME UP WITH THE WARM FRONT. WILL LIKELY MAKE IT
TOUGH FOR MUCH OF THE MN CWA TO DIP BELOW 70 SUNDAY MORNING...WHICH
WILL HAVE IMPLICATIONS ON THE POTENTIAL NEED FOR ANY HEAT HEADLINES
SUNDAY. NOT WORRIED ABOUT FOG TONIGHT EITHER...AS GRADIENT WILL
REMAIN STRONG THROUGH THE NIGHT...SO WILL BE ANOTHER NIGHT LIKE
TONIGHT WHERE WE JUST WATCH ANY STRATUS THAT SURVIVES THE DAY TODAY
EXPAND AGAIN OVERNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 350 AM CDT SAT AUG 23 2014
THERE IS DEFINITELY SOME SPREAD IN THE MODEL GUIDANCE AS WE HEAD
THROUGH THE LATTER PORTION OF THE FORECAST... BUT THE GENERAL
SCENARIO SUGGESTS A TRANSITION FOR WESTERN RIDGE/EASTERN TROUGH TO
MORE OF A ZONAL PATTERN BY THE END OF THE WEEK. THIS SHOULD ALLOW
FOR TEMPERATURES TO TREND FROM ABOVE NORMAL TO NEAR NORMAL AS THE
WEEK UNFOLDS... WITH PCPN CHANCES BEING A BIT TOUGH TO PIN DOWN
DEPENDING UPON WHERE THE MAIN BAROCLINIC ZONE SETS UP. GIVEN THE
SPREAD IN DETERMINISTIC AND ENSEMBLE GUIDANCE... A CONSENSUS
APPROACH IS THE MOST SENSIBLE COURSE OF ACTION... SO STUCK CLOSE
TO A MULTI-MODEL BLEND.
THE MAIN FORECAST ISSUES LOOK TO BE THE POTENTIAL FOR EXCESSIVE
HEAT/HUMIDITY SUNDAY... THEN THE POSSIBILITY OF SIGNIFICANT PCPN
OVER THE SOUTHERN PORTION OF THE AREA LATE MONDAY THROUGH
WEDNESDAY AS THE FRONTAL BOUNDARY HANGS UP SOMEWHERE NEAR THE
MINNESOTA/IOWA BORDER. SUNDAY STILL LOOKS TO HAVE THE POTENTIAL
FOR VERY WARM TEMPERATURES ACROSS THE AREA... ALONG WITH HIGH
DEWPOINTS. AT THIS POINT... APPARENT TEMPERATURE FORECASTS PEAK
AROUND 100 OVER A PORTION OF THE AREA SUNDAY AFTERNOON WITH
FORECAST HIGHS IN THE LOW 90S AND DEWPOINTS NEAR 70. WET BULB
GLOBE TEMPERATURES JUMP INTO THE LOWER TO MIDDLE 80S AS WELL...
ALSO INDICATING THE POTENTIAL FOR HEAT RELATED ISSUES FOR PEOPLE
WHO MAY BE OUTDOORS ON SUNDAY. THERE WILL CERTAINLY BE A
SIGNIFICANT NUMBER OF PEOPLE OUTDOORS IN THE METRO AREA ON SUNDAY
WITH THE GREAT MINNESOTA GET TOGETHER IN FULL SWING... SO THE
POSSIBILITY OF EXCESSIVE HEAT/HUMIDITY WILL NEED TO BE MONITORED
IN SUBSEQUENT FORECASTS. AT THIS POINT... THERE IS STILL SOME
UNCERTAINTY IN CLOUD COVER AND WHETHER WE/LL MIX AS WELL AS SOME
GUIDANCE SUGGESTS AND/OR SEE MORE LOW LEVEL EVAPORATIVE COOLING
THAN ANTICIPATED. SO... WILL HIGHLIGHT THE POSSIBILITY IN THE
HAZARDOUS WEATHER OUTLOOK AND OTHER SERVICES... BUT HOLD OFF ON
ANY ACTUAL HEADLINES AT THIS POINT. PCPN CHANCES ON SUNDAY LOOK TO
BE CONFINED TO THE WESTERN/NORTHERN PORTION OF THE AREA UNTIL
LATE AFTERNOON AND/OR EVENING WHEN THE COLD FRONT FINALLY STARTS
TO WORK ITS WAY EAST ACROSS THE AREA. AT THAT POINT... THE MAIN
LARGE SCALE FORCING WILL BE TO OUR NORTH... SO PCPN MAY BE
SCATTERED IN NATURE WITH MORE WIDESPREAD ACTIVITY WITH THE
SHORTWAVE AND TRIPLE-POINT TO OUR NORTH AND THE SECONDARY WARM
ADVECTION/INSTABILITY NOSE TO OUR SOUTH. DEEP LAYER SHEAR WILL BE
BEST TO OUR NORTH... SO ANY SEVERE POTENTIAL LOOKS TO BE CAPE-
DRIVEN WITH MAINLY MULTI-CELL WIND/HAIL STORMS BEING THE CONCERN.
CHANCES FOR PCPN WILL PUSH EAST SUNDAY NIGHT WITH THE FRONT...
THEN WE/LL SEE HIGH PRESSURE BUILD OVER MUCH OF THE AREA.
HOWEVER... THE FRONTAL BOUNDARY LOOKS TO HANG UP TO OUR SOUTH/EAST
MONDAY INTO WEDNESDAY... NECESSITATING THE INCLUSION OF POPS OVER
MUCH OF THE AREA DURING THAT TIME FRAME... WITH BETTER CHANCES
SOUTH AND LOW CHANCES NORTH. THE FAR SOUTHERN PORTION OF THE AREA
HAS SOME POTENTIAL TO SEE SIGNIFICANT RAINFALL OVER THAT PERIOD OF
TIME... BUT MUCH WILL DEPEND ON WHERE SUCCESSIVE ROUNDS OF
SHRA/TSRA DECIDE TO TRACK... AND IT IS TOO EARLY TO GET A GOOD
HANDLE ON THAT EVOLUTION. WE SHOULD SEE HIGH PRESSURE...
SUBSIDENCE... AND DRIER AIR WORK INTO THE ENTIRE AREA FROM THE
NORTHWEST WEDNESDAY NIGHT THROUGH THE REMAINDER OF THE FORECAST
PERIOD... WITH DRY WEATHER PREDOMINATING. HOWEVER... THE 00Z ECMWF
IS A BIT SLOWER IN SHOWING THIS EVOLUTION IN COMPARISON TO ITS
PREVIOUS RUNS OR THE 00Z GFS... SO WE/LL NEED TO SEE HOW THINGS
EVOLVE IN SUBSEQUENT FORECASTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1047 PM CDT FRI AUG 22 2014
LINGERING MVFR CEILINGS OVER NERN PORTIONS OF THE COVERAGE AREA
SLOWLY RECEDED NE THIS EVE BUT STILL HELD OVER KRNH WHILE THE
REMAINING TAF SITES HELD IN VFR. BY LATE EVENING...THE PLENTIFUL
LOW LEVEL MOISTURE AND LIGHT WINDS WILL AGAIN COMBINE TO PRODUCE
IFR-OR-LOWER CONDITIONS...MAINLY DUE TO CEILINGS BUT ALSO
POTENTIALLY FOG FOR THE USUAL SUSPECTS /A.K.A. KSTC...KRNH AND
KEAU/. HAVE MAINTAINED THIS THINKING IN THE 00Z TAFS WITH THE
WORST CONDITIONS MAINLY BETWEEN 08Z-14Z SAT. CONDS THEN LOOK TO
SLOWLY IMPROVE THRU THE MRNG HOURS. ONE OTHER COMPLICATION IS THE
POTENTIAL DEVELOPMENT OF SCATTERED TO NUMEROUS SHOWERS/TSTMS OVER
ERN SD/ERN NE/WRN IA THAT WILL SPREAD INTO SWRN MN BY AROUND
DAYBREAK THRU LATE MRNG. THIS WOULD AFFECT KRWF-KAXN-KSTC LATE
MRNG INTO THE EARLY AFTN. TOO EARLY ATTM TO DETERMINE FLIGHT COND
DETERIORATION BUT WILL FOR NOW SHOW PREVAILING PRECIP AT THE WRN
TAF SITES.
BY LATE EVENING...THE PLENTIFUL
LOW LEVEL MOISTURE AND LIGHT WINDS WILL AGAIN COMBINE TO PRODUCE
IFR- OR-LOWER CONDITIONS...MAINLY DUE TO CEILINGS BUT ALSO
POTENTIALLY FOG FOR THE USUAL SUSPECTS /A.K.A. KSTC...KRNH AND
KEAU/. HAVE MAINTAINED THIS THINKING IN THE 00Z TAFS WITH THE
WORST CONDITIONS MAINLY BETWEEN 08Z-14Z SAT. CONDS THEN LOOK TO
SLOWLY IMPROVE THRU THE MRNG HOURS. ONE OTHER COMPLICATION IS THE
POTENTIAL DEVELOPMENT OF SCATTERED TO NUMEROUS SHOWERS/TSTMS OVER
ERN SD/ERN NE/WRN IA THAT WILL SPREAD INTO SWRN MN BY AROUND
DAYBREAK THRU LATE MRNG. THIS WOULD AFFECT KRWF-KAXN-KSTC LATE
MRNG INTO THE EARLY AFTN. TOO EARLY ATTM TO DETERMINE FLIGHT COND
DETERIORATION BUT WILL FOR NOW SHOW PREVAILING PRECIP AT THE WRN
TAF SITES.
KMSP...CONDS BOUNCED BETWEEN VFR AND MVFR FOR MUCH OF THE
EVENING...FINALLY HOLDING AT VFR COMING INTO THE 06Z
INITIALIZATION TIME. AM STILL LOOKING FOR CONDS TO DROP TO
SUB-1700 FT CEILINGS LATER TONIGHT AND HOLDING THERE THRU THE
EARLY MRNG HRS. IFR CONDS THEN SETTLE IN CLOSE TO DAYBREAK BUT AM
NOT XPCTG MUCH OF A VSBY RESTRICTION FROM VFR...JUST INTO MVFR.
THE IFR CIGS WILL THEN LIKELY LAST THRU LATE MRNG TO AROUND
MIDDAY...WITH VFR CONDS EXPECTED TMRW AFTN. DEGRADED CONDS
EXPECTED AGAIN SAT EVENING...BUT AM ONLY ADVERTISING MVFR CIGS
ATTM AND THIS DEGRADATION MAY BE LATER THAN ADVERTISED.
/OUTLOOK FOR KMSP/
SUN...VFR. MVFR/TSRA POSSIBLE EVENING/OVERNIGHT. WINDS S10G20 KTS.
MON...VFR. WINDS W 5-10 KTS.
TUE...MAINLY VFR. CHC MVFR IN TSRA. WINDS NE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...
AVIATION...JPC
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1010 PM MDT FRI AUG 22 2014
.UPDATE...
HAVE ISSUED A FLOOD WATCH FOR FAR SE MT AS ROUNDS OF HEAVY
RAIN/EMBEDDED TSTMS EXPECTED TO LAST THROUGH THE NIGHT AND INTO
SATURDAY...AS MONSOONAL ENERGY LIFTS UP THE HIGH PLAINS.
A LONE SEVERE STORM IMPACTED SOUTHEAST MT A LITTLE WEST OF
BROADUS EARLIER THIS EVENING. THIS HAS DISSIPATED AND CONVECTION
IS FOCUSED IN SOUTHERN CARTER COUNTY NOW...AND IS NOT EXPECTED TO
BECOME SEVERE. SHOWER ACTIVITY IS GRADUALLY BECOMING MORE
WIDESPREAD ACROSS THE CWA IN RESPONSE TO INCREASING LARGE SCALE
ASCENT WITH DEEP TROF DIGGING INTO IDAHO. LATEST H3 ANALYSIS SHOWS
A VERY IMPRESSIVE 100 KT JET FROM OREGON INTO NEVADA...WITH STRONG
DIFFLUENCE SHOWN ON SATELLITE IMAGERY FROM UTAH INTO SOUTHEAST
IDAHO. ASCENT FROM THE UPPER LOW WILL ONLY INCREASE THROUGH THE
NIGHT...AND IN FACT PER LATEST BLX VAD WINDS WE ARE SEEING
EASTERLY UPSLOPE WINDS THROUGH 10KFT NOW. VERY IMPRESSIVE DYNAMICS
FOR THE THIRD WEEK IN AUGUST.
THERE REMAINS SOME UNCERTAINTY REGARDING TRACK OF MID LEVEL LOW BY
EARLY SATURDAY MORNING WITH THE LATEST RAP SHOWING A WEAK 700MB
LOW JUST NORTH OF BILLINGS...AND THIS IS NOT TOO DISSIMILAR TO THE
NEW 00Z NAM...WITH THE GFS BEING A BIT FURTHER NORTH. SO AFTER A
GOOD PERIOD OF RAIN TONIGHT WE MAY SEE THE HEAVIER PCPN SHIFT TO
MAINLY OUR NORTH AND EAST PARTS FOR TOMORROW. THAT BEING SAID...
RAP SHOWS 300MB LOW OVER SOUTHEAST IDAHO SATURDAY MORNING WHICH
PUTS OUR AREA IN A VERY DIFFLUENT FLOW ALOFT...SO FEEL EVEN WITH
SOME DEGREE OF LOW LEVEL DOWNSLOPING BY SATURDAY MORNING WE WILL
STILL SEE ENOUGH ASCENT FOR SHOWERS IN THE BILLINGS AREA.
INSTABILITY SHOULD REMAIN GREAT ENOUGH FOR EMBEDDED SCATTERED
THUNDERSTORMS IN OUR EAST...OTHERWISE WE ARE LOOKING AT SHOWERS
W/ ONLY ISOLD TSTMS THROUGH TOMORROW.
FOR THE UPDATE HAVE RAISED POPS A BIT MORE ACROSS MUCH OF THE
AREA TONIGHT AND SATURDAY. OVERALL FORECAST REMAINS ON TRACK. ITS
GOING TO BE WET FOLKS.
JKL
&&
.SHORT TERM...VALID FOR SAT AND SUN...
BROAD UPPER TROUGH OVER THE PACIFIC NW WILL CONTINUE TO PRODUCE
AN UNUSUALLY COOL AND WET PERIOD ACROSS OUR REGION THE NEXT COUPLE
OF DAYS. IF I WERE TO PICK A WETTEST PERIOD...IT WOULD BE TONIGHT
INTO SATURDAY MORNING AS PLENTY OF LIFT IS PROGGED OVER OUR
FORECAST AREA. ASSOCIATED JET DYNAMICS AND STRONG ISENTROPIC LIFT
OUT IN FRONT OF THE UPPER TROUGH WILL LIKELY PRODUCE WIDESPREAD
RAIN AND EMBEDDED THUNDER OVER THE AREA. SOME DISCRETE STRONG
THUNDERSTORM CELLS ARE ALSO POSSIBLE FROM SHERIDAN TO CARTER
COUNTY THIS EVENING AS EFFECTIVE SHEAR INCREASES ACROSS THIS AREA
WITH A JET STREAK ALOFT. ONE OR TWO STRONG TO SEVERE STORMS ARE
POSSIBLE IN THIS AREA DUE TO THE INCREASING POSSIBILITY OF
SUSTAINED UPDRAFTS. LOOK FOR A VERY MOIST ATMOSPHERE WITH AREAS OF
FOG AND LIGHT RAIN OVERNIGHT.
SATURDAY...NEGATIVE TILT TROUGH WORKS INTO THE REGION FROM THE
WEST AND MAY PRODUCE SOME STRONG TO SEVERE STORMS IN THE SE CORNER
OF THE STATE DUE TO STRONG SHEAR AND INSTABILITY/LIFT. SEVERAL
POCKETS OF LIFT WILL PRODUCE AREAS OF RAIN...MAINLY OVER THE
NORTHERN AND EASTERN ZONES THROUGH SATURDAY. BY SATURDAY EVENING
AS THE UPPER LOW MOVES OVER THERE IS SOME HINT OF DOWNSLOPE DRYING
FROM HARLOWTON TO YELLOWSTONE COUNTY DUE TO NORTH/NORTHWEST FLOW
WRAPPING AROUND THE LOW PRESSURE SYSTEM. THE ECMWF WANTS TO KEEP A
CLOSED UPPER LOW OVER SE MONTANA WHILE THE GFS LIFTS THE SYSTEM
NORTH. THE ECMWF VERSION IS MUCH WETTER THAN THE GFS. THERE IS NO
REAL WAY TO DISCERN WHICH SOLUTION IS MOST ACCURATE AT THIS TIME
...THOUGH THE GFS HAS SUPPORT FROM THE NAM...AND GFS ENSEMBLE
SPREADS ARE NOT THAT WIDE. THEREFORE...I HAVE BLENDED THE WET/DRY
SOLUTIONS BUT LEANED A BIT MORE ON THE LESS WET GFS SOLUTION GOING
INTO SUNDAY. LOOK FOR A BLUSTERY SATURDAY NIGHT AND SUNDAY WITH
NORTH WINDS 15 TO 25 MPH COMBINED WITH THE RAINY CONDITIONS.
BY SUNDAY NIGHT THE UPPER LOW IS TRACKING ACROSS NORTH DAKOTA WITH
A MID LEVEL ZONAL FLOW SPREADING OVER MONTANA AND GENERALLY
BRINGING MOST OF THE PRECIPITATION TO AN END OVER OUR FORECAST
AREA. BT
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
MINIMAL UPDATES THIS AFTERNOON FOR THE INHERITED EXTENDED
FORECAST...WITH MODELS IN GOOD AGREEMENT THROUGHOUT THE
PERIOD.
A SECONDARY LOBE OF THE BROAD UPPER TROF IS STILL VERY SLOW TO
PUSH OFF TO THE EAST. THE TROF AXIS WILL BEGIN SLOW PROGRESSION
EASTWARD MONDAY. THIS WILL BRING ANOTHER ROUND OF PRECIP THROUGH
THE REGION BEGINNING MONDAY...AND LINGERING THROUGH MUCH OF
TUESDAY. THE DYNAMICS FOR THIS SYSTEM APPEARS MUCH WEAKER...SO
EXPECT SHOWERS AND THUNDERSTORMS TO BE MORE SCATTERED IN NATURE.
THE SLOW MOVEMENT OF THE TROF WILL KEEP TEMPS WELL BELOW SEASONAL
AVERAGE...WITH HIGHS IN THE LOW TO MID 70S EACH DAY.
AN UPPER LEVEL RIDGE BEGINS BUILDING INTO THE REGION OVERNIGHT
TUESDAY NIGHT...AND IS THEN FOLLOWED BY ZONAL FLOW DEVELOPING LATE
THURSDAY. THEREFORE EXPECT WARMER AND DRIER CONDITIONS TO PREVAIL
THROUGH THE REMAINDER OF THE EXTENDED PERIOD. TEMPERATURES WILL
SLOWLY TREND UPWARD...BUT GENERALLY REMAIN AROUND SEASONAL AVERAGE.
AAG
&&
.AVIATION...
SCATTERED SHOWERS...AND A FEW THUNDERSTORMS...WILL IMPACT ALL
TERMINALS TONIGHT. EXPECTING MVFR AND IFR CONDITIONS WITH
OCCASIONAL HEAVY RAINFALL THROUGH THE NIGHTTIME HOURS. CEILINGS
WILL REMAIN LOW UNTIL THE DAYBREAK HOURS. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 056/063 049/065 048/071 050/075 053/082 057/087 061/085
+8/T 44/T 23/T 32/T 11/U 01/U 11/U
LVM 051/060 045/064 042/070 044/075 048/083 051/086 051/084
+8/T 43/T 25/T 52/T 11/B 01/U 12/T
HDN 057/068 050/066 046/074 050/077 051/083 055/088 059/088
98/T 55/T 13/T 32/T 11/U 01/U 11/U
MLS 060/067 052/062 047/071 051/074 053/082 057/087 062/090
++/T 86/T 22/T 22/T 11/U 11/U 11/B
4BQ 060/071 051/064 046/071 052/073 051/081 056/087 060/089
89/T 63/T 22/T 33/T 11/U 11/U 11/U
BHK 056/066 050/061 046/069 047/071 048/078 053/083 059/086
9+/T 86/T 22/T 23/T 11/U 11/U 11/B
SHR 055/070 047/065 044/073 048/074 048/081 051/087 055/089
76/T 53/T 13/T 43/T 11/U 01/U 11/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...FLOOD WATCH IN EFFECT THROUGH SATURDAY AFTERNOON FOR ZONES
32-33-36-37.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
553 PM CDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 313 PM CDT SAT AUG 23 2014
H5 ANALYSIS FROM THIS MORNING HAS RIDGING ACROSS THE
MISSISSIPPI VALLEY FROM THE GULF COAST NWD INTO THE WESTERN GREAT
LAKES. FURTHER EAST...DECENT SHORTWAVES WERE NOTED OVER LAKE ONTARIO
AND NOVA SCOTIA. FURTHER WEST...A TANDEM OF SHORTWAVES WERE LOCATED OVER
THE INTERMOUNTAIN WEST. THE FIRST OVER WESTERN COLORADO AND A SECOND
OVER EASTERN IDAHO...WHILE ANOTHER SHORTWAVE WAS UPSTREAM OVER THE
ALASKA PANHANDLE. WV IMAGERY AS OF 1 PM CDT...INDICATED SHORTWAVE
ENERGY IN ASSOCIATION WITH THE WAVE OVER WESTERN COLORADO HAD BEGUN
TO EMERGE ACROSS CENTRAL COLORADO AND HAS LED TO INCREASING
CLOUDINESS ALONG THE FRONT RANGE OF COLORADO. OVER THE NEXT COUPLE
OF HRS...SHRAS AND TSRAS ARE EXPECTED TO DEVELOP ON THE LEE SIDE OF
THE ROCKIES INVOF THE FRONT RANGES OF COLORADO AND WYOMING. FURTHER
WEST...A CLOSED LOW REMAINS IN PLACE OVER EASTERN IDAHO ATTM WITH A
BROAD AREA OF CLOUDS AND SHOWERS ACROSS MONTANA...NORTH DAKOTA AND
NORTHERN SOUTH DAKOTA. ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA...ABUNDANT CLOUDINESS WAS PRESENT OVER MOST OF THE AREA
WITH THE EXCEPTION OF FAR SWRN NEBRASKA AND THE EASTERN NEBRASKA
PANHANDLE WHERE CLOUDS HAVE SCATTERED OUT OVER THE PAST 1 TO 2
HOURS. AT THE SURFACE...A TANDEM OF LOW PRESSURE CENTERS WERE
PRESENT ACROSS SERN WYOMING AND A SECOND OVER SOUTH CENTRAL SD. A
WARM FRONT EXTENDED FROM SERN WYOMING INTO EASTERN SOUTH
DAKOTA...WHILE A COLD FRONT EXTENDED SSWD INTO THE CENTRAL ROCKIES.
UNDER PARTLY TO MOSTLY CLOUDY SKIES...TEMPERATURES AS OF 3 PM
CDT...RANGED FROM 72 AT AINSWORTH...TO 82 AT BROKEN BOW.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 313 PM CDT SAT AUG 23 2014
MODELS REMAIN IN GOOD AGREEMENT
WITH THE PROJECTIONS OF A PV ANOMALY LIFTING NORTHEAST FROM FAR
SOUTHWESTERN WYOMING TOWARD THE NORTHERN PLAINS THIS EVENING AND
OVERNIGHT. RECENT OBSERVATIONS INDICATE THAT THE LOW STRATUS IS
DISSIPATING EARLY THIS AFTERNOON...LEADING TO THE EVENTUAL
DESTABILIZATION OF THE LOWER TROPOSPHERE. AS HEIGHTS FALL WITH THE
APPROACH OF THE PV MAX/ATTENDANT COLD FRONT...STORMS ARE ANTICIPATED
TO FORM INVOF OF THE HIGH PLAINS SURFACE LOW/FRONTAL BOUNDARY AND
POSSIBLY DRIFT EAST ACROSS THE SANDHILLS REGION OF NEB OVERNIGHT.
THE LATEST PROJECTIONS FROM THE RAP AND HRRR SHOWS THAT DESPITE THE
MORNING CLOUDS...LOW TO MID LEVEL LAPSE RATES HAVE INCREASED
SOME...YIELDING A WEAKLY UNSTABLE ATMOSPHERE ACROSS WESTERN PORTIONS
OF THE CWA /CONTINUED CLEARING WILL ALLOW FOR FURTHER
DESTABILIZATION/. THE PROJECTED INSTABILITY /UPWARDS TO 1000 J/KG
ML CAPE/ COMBINED WITH 0-6KM BULK SHEAR OF 30KTS OR SO WILL PROMOTE
THE POSSIBILITY OF STRONG TO LOW END SEVERE STORMS THIS EVENING AND
OVERNIGHT. ANOTHER AREA TO WATCH FOR SEVERE STORMS WILL BE ACROSS
NORTH CENTRAL NEBRASKA LATE THIS AFTERNOON AS A SECONDARY WARM FRONT
LIFTS NORTH TOWARD THE SOUTHEAST SOUTH DAKOTA. ABUNDANT INSTABILITY
AND SUFFICIENT SHEAR WOULD PROMOTE RAPID STORM DEVELOPMENT CAPABLE
OF LARGE HAIL AND DAMAGING WIND GUSTS.
THE HEAVY RAIN THREAT WILL BE NOTICEABLY LESS TONIGHT AS BUFR
SOUNDINGS REVEAL A MUCH LESSER INFLUENCE FROM WARM RAIN
PROCESSES...BUT WITH PWATS AT OR SLIGHTLY ABOVE AVERAGE...BRIEF
HEAVY RAINFALL IS STILL POSSIBLE.
THE COLD FRONT CLEARS THE CWA EARLY ON SUNDAY WITH RAIN CHANCES
POSSIBLY LINGERING ACROSS OUR FAR EAST THROUGH 15Z...OTHERWISE A
SLIGHTLY COOLER AIRMASS IS ANTICIPATED WITH HIGHS RANGING FROM THE
MID 70S ACROSS OUR FAR NORTHWEST...TO LOW TO MID 80S SOUTH OF THE
INTERSTATE 80 CORRIDOR. WITH MOISTURE LACKING AND A STABLE AIRMASS
ANTICIPATED SUNDAY AFTERNOON...STORM CHANCES SHOULD BE KEPT AT BAY
UNTIL AT LEAST 00Z MONDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CDT SAT AUG 23 2014
SUNDAY NIGHT THROUGH TUESDAY...THE MAIN FORECASTING
CHALLENGE CONTINUES TO BE PRECIPITATION CHANCES AND THE THREAT FOR
HEAVY RAIN AS A TROUGH AND SEMI STATIONARY FRONTAL BOUNDARY PERSISTS
ACROSS THE CENTRAL ROCKIES AND PLAINS DURING THE PERIOD. FOR SUNDAY
NIGHT...AFTER RELATIVELY QUIET WEATHER CONDS SUNDAY...MID LEVEL WAA
WILL INCREASE ALONG THE FRONT RANGE DURING THE
EVENING...TRANSITIONING EAST ACROSS THE CENTRAL PLAINS OVERNIGHT
SUNDAY NIGHT INTO EARLY MONDAY. AT THE SAME TIME...A NICE H250 JET
STREAK WILL LIFT ACROSS NWRN NEBRASKA INTO SOUTH DAKOTA PLACING
WESTERN AND NORTH CENTRAL NEBRASKA IN THE RIGHT REAR QUAD OF THIS
FEATURE. ENHANCED LIFT ACROSS THE FORECAST AREA...WILL LEAD TO A
SHARP INCREASE IN THE THREAT OF PCPN SUNDAY NIGHT INTO MONDAY. IN
THE LOWER LEVELS...A FRONTAL BOUNDARY WILL BE ANCHORED ACROSS SRN
NEBRASKA SUNDAY NIGHT WITH THE NOSE OF A H85 LOW LEVEL JET
POSITIONED ACROSS SWRN NEBRASKA. INHERITED FCST HAD THE HIGHEST POPS
ACROSS SRN PORTIONS OF THE FORECAST AREA SUNDAY NIGHT INTO MONDAY
MORNING AND APPEARS ON TRACK ATTM. PRECIPITATION CHANCES WILL
DECREASE SOMEWHAT MONDAY AS MID LEVEL FORCING PUSHES EAST INTO THE
MID MISSOURI VALLEY. BY MONDAY NIGHT...ANOTHER STRONG UPPER LEVEL
DISTURBANCE WILL PUSH ACROSS THE CENTRAL PLAINS...LEADING TO
INCREASED CHANCES FOR RAIN MONDAY NIGHT...AS WELL AS TUESDAY NIGHT. LOW
LEVEL EASTERLY WINDS AND ABUNDANT MID AND UPPER LEVEL MOISTURE
TRANSPORT FROM THE SOUTHWEST IN ASSOCIATION WITH HURRICANE MARIE
COULD LEAD TO HEAVY RAIN ACROSS THE CENTRAL PLAINS BEGINNING MONDAY
NIGHT AND POSSIBLY PERSISTING INTO TUESDAY NIGHT. FURTHER SUPPORT
FOR HEAVY RAIN IS EVIDENT IN FCST PWATS RANGING FROM 1.5 TO 2.0
INCHES MONDAY NIGHT THROUGH TUESDAY NIGHT.
WEDNESDAY THROUGH SATURDAY...LINGERING PCPN CHANCES ARE THE MAIN
FORECAST CHALLENGE IN THE LONG RANGE PERIODS. BY WEDNESDAY INTO
THURSDAY...THE PERSISTENT UPPER LEVEL TROUGH ACROSS THE
ROCKIES...WILL CROSS THE CENTRAL PLAINS INTO THE MISSISSIPPI VALLEY.
THE LATEST GFS SOLN IS 24 HRS FASTER COMPARED TO THE ECMWF IN
LIFTING THIS FEATURE EAST OF THE AREA. THE GFS IS DRY AFTER WEDS
WITH THE TROUGH OVER MISSOURI VALLEY BY 12Z THURSDAY...WHILE THE
ECMWF HAS THIS FEATURE OVER THE SAME AREA BY 12Z FRIDAY. INHERITED
FCST WAS DRY WEDS NIGHT AND INTRODUCED POPS FOR THIS PERIOD AS BOTH
MODELS HAVE TRENDED SLOWER. WILL HOLD OFF ON INTRODUCING POPS FOR
THURSDAY FOR NOW AND WAIT FOR THE MODELS TO COME INTO BETTER
AGREEMENT. AFTER UNSEASONABLY COOL HIGHS IN THE 70S FOR WEDNESDAY
AND THURSDAY...HIGHS WILL REBOUND BACK INTO THE 80S FOR THURSDAY AND
FRIDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 553 PM CDT SAT AUG 23 2014
A PACIFIC COLD FRONT IS ENTERING WRN NEB THIS EVENING. THE FRONT
IS EXPECTED TO BE THE FOCUS FOR CONTINUED TSTM DEVELOPMENT
OVERNIGHT. STORM ACTIVITY IS EXPECTED TO DIMINISH IN COVERAGE
ACROSS NCNTL NEB BY 12Z SUNDAY AND VFR IS EXPECTED THEREAFTER ALL
AREAS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JACOBS
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
359 PM CDT SAT AUG 23 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 345 PM CDT SAT AUG 23 2014
STUBBORN LOWER CLOUDS STILL HANGING ON ACROSS NORTHWEST PART OF
THE FORECAST AREA. SULTRY AIRMASS TODAY AS WELL...WITH DEWPOINTS
AROUND 70 SEVERAL LOCATIONS. MOST MODELS TRY TO PUMP IN SOME DRIER
AIR FROM THE SOUTH THROUGH THIS EVENING...WITH THE HRRR MOST
AGGRESSIVE. THAT COULD PROVIDE A LITTLE HUMIDITY RELIEF TO SOME
SPOTS IN THE SOUTHERN/SOUTHEAST FORECAST AREA. AS WE WORK INTO
TONIGHT...THE PROSPECT OF THUNDERSTORMS IS MUCH MUCH LOWER...BUT
NOT NIL. A DECENT LOW LEVEL JET WILL DEVELOP AND THAT COULD SUSTAIN
HIGH PLAINS CONVECTION...BUT ALSO SPARK A FEW OTHER ISOLATED SHOWERS
AND STORMS. OVERALL COVERAGE SHOULD BE ISOLATED...BUT CAN NOT
TOTALLY RULE IT OUT.
SUNDAY SHOULD START WITH LINGERING MID/HIGH CLOUDS FROM LEFTOVER
SHOWERS AND THUNDERSTORMS IN PARTS OF THE PLAINS. THESE MAY HOLD
OVER INTO THE POST SUNRISE HOURS OVER NORTHERN PARTS OF THE
FORECAST NEAR A FRONTAL BOUNDARY...BUT COVERAGE WILL BE SPARSE
AND 20 PERCENT CHANCES REPRESENT RAIN RISK WELL.
A WEAK FRONTAL BOUNDARY WILL ATTEMPT TO MOVE ACROSS THE FORECAST
AREA SUNDAY. MODELS SEEM A BIT AGGRESSIVE...BUT SOMETIMES THAT DOES
WORK OUT. EXPECT A SHIFTING WIND...AND THEN A DYING WIND AS THE
FORECAST IS LEFT TO FLOUNDER IN THE SURFACE SURFACE WITH THE FRONT
WEAKENING WITH TIME. THE WEAK NATURE OF THE FRONT AND SOME WARM MID
LEVEL TEMPERATURES WILL PROBABLY KEEP ANY DEVELOPMENT OF
THUNDERSTORMS NEAR OR ALONG THE FRONT VERY SPARSE AND TOWARD EVENING
AT THE EARLIEST. HAVE KEPT SIMILAR IDEA OF LOWER DEWPOINTS BEHIND
THE FRONTAL PASSAGE...BUT HAVE SOME DOUBT PLACES LIKE GRAND ISLAND
AND HASTINGS COULD DROP TO A SUB-60 DEWPOINT LATE SUNDAY AFTERNOON.
THAT WOULD BE NICE BUT WE WILL SEE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 345 PM CDT SAT AUG 23 2014
UNSETTLED WEATHER CONDITIONS WILL CONTINUE THROUGH MUCH OF THE
EXTENDED PERIODS AS THE LOCAL AREA WILL REMAIN UNDER THE INFLUENCE
OF A LARGE TROUGH OF LOW PRESSURE ACROSS THE INTERMOUNTAIN WEST
WITH WEST TO SOUTHWESTERLY FLOW PERSISTING ALOFT.
EXPECT THE MAIN UPPER LEVEL LOW ACROSS THE DAKOTAS SUNDAY EVENING
TO LIFT NORTHEAST...WITH A SECONDARY FRONTAL BOUNDARY PUSHING
ACROSS THE LOCAL AREA. WHILE THIS FRONTAL BOUNDARY MAY PROVIDE THE
TRIGGER FOR SOME ELEVATED CONVECTION ACROSS THE SOUTHEASTERN
PORTIONS OF THE LOCAL AREA EARLY IN THE EVENING...EXPECT THE
BETTER CHANCES TO SPREAD FROM WEST TO EAST AFTER MIDNIGHT AS A
TRAILING MID LEVEL DISTURBANCE MOVES ACROSS THE LOCAL AREA FROM
THE HIGH PLAINS AND A WEAK LOW LEVEL JET FOCUSES ITSELF ACROSS
NORTH CENTRAL KANSAS.
AS THIS FIRST UPPER LEVEL LOW TRACKS WELL INTO CANADA...EXPECT A
SECOND UPPER LEVEL LOW TO SLIDE FROM THE PACIFIC NORTHWEST AND
INTO THE INTERMOUNTAIN WEST BY MONDAY...MAINTAINING SOUTHWESTERLY
ALOFT ACROSS THE REGION. WHILE CHANCES FOR PRECIPITATION WILL
DECREASE SOME DURING THE DAY ON MONDAY...KEPT SOME SMALL POPS IN
THE FORECAST AS THE OLD FRONTAL BOUNDARY WILL BE MEANDERING
ACROSS THE REGION. THAT SAID...THE BETTER SHOT FOR MORE
WIDESPREAD CONVECTION WILL BE MONDAY NIGHT...AS YET ANOTHER UPPER
LEVEL DISTURBANCE IN SOUTHWESTERLY FLOW TRAVERSES THE REGION IN
CONCERT WITH AN INCREASING LOW LEVEL JET AIMED ACROSS SOUTH
CENTRAL NEBRASKA. WITH SEVERAL THOUSAND JOULES OF CAPE IN PLACE
AND MODEST SHEAR VALUES FORECAST...EXPECT THE POTENTIAL FOR AN
ACTIVE NIGHT ACROSS THE LOCAL AREA...ESPECIALLY FROM THE STATE
LINE NORTH. DUE TO SOME DISCREPANCIES IN MODEL DATA...
HOWEVER...ONLY WENT AHEAD AND ADVERTISED LIMITED SEVERE POTENTIAL
FOR MONDAY NIGHT IN THE HWO.
OTHERWISE...THUNDERSTORM ACTIVITY TUESDAY SHOULD ONCE AGAIN BE
FOCUSED NEAR THE LOW LEVEL JET DURING THE EVENING AND OVERNIGHT
HOURS...WITH A COLD FRONT EXPECTED TO BRING YET ANOTHER CHANCE
FOR THUNDERSTORMS ACROSS THE LOCAL AREA WEDNESDAY AND WEDNESDAY
NIGHT. WHILE A CHANCE FOR PRECIPITATION IS IN THE FORECAST SUNDAY
THROUGH THURSDAY...AT THIS TIME THE BEST POTENTIAL FOR ANY SEVERE
WEATHER APPEARS TO BE PRIMARILY DURING THE EVENING AND OVERNIGHT
HOURS MONDAY THROUGH WEDNESDAY...WITH A COOLER...DRIER...AND MORE
STABLE AIRMASS EXPECTED TO SETTLE IN ACROSS THE REGION TO END THE
WEEK.
HYDROLOGY WISE...DUE TO THE RECENT RAINFALL AND SATURATED SOILS
ACROSS MUCH OF THE LOCAL AREA...CONTINUED WITH THE MENTION OF
LOCALIZED FLOODING THE HWO IN THIS UNSETTLED PATTERN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1235 PM CDT SAT AUG 23 2014
SLOWLY ERODING LOW CLOUDS OUT OF SOUTH CENTRAL NEBRASKA. GRAND
ISLAND PRETTY MUCH IN THE CLEAR IT APPEARS...WHILE KEARNEY MAY
SKIRT WITH SOME SCATTERED AFTERNOON CLOUDS BUT OVERALL TREND
SHOULD BE CLEARING OUT. WINDS WILL CONTINUE TO INCREASE AHEAD
OF DEEPENING LOW LEVEL TROUGH WITH GUSTS OVER 20 MPH NOT UNCOMMON.
PRECIPITATION WHICH DEVELOPS TO THE WEST TONIGHT COULD MOVE INTO
THE AREA LATE IN THE FORECAST...BUT WAS NOT CONFIDENT IN ITS
COVERAGE TO ADD TO FORECAST AT THIS TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...MORITZ
LONG TERM...ROSSI
AVIATION...NOAA/NWS/MORITZ
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
313 PM CDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 313 PM CDT SAT AUG 23 2014
H5 ANALYSIS FROM THIS MORNING HAS RIDGING ACROSS THE
MISSISSIPPI VALLEY FROM THE GULF COAST NWD INTO THE WESTERN GREAT
LAKES. FURTHER EAST...DECENT SHORTWAVES WERE NOTED OVER LAKE ONTARIO
AND NOVA SCOTIA. FURTHER WEST...A TANDEM OF SHORTWAVES WERE LOCATED OVER
THE INTERMOUNTAIN WEST. THE FIRST OVER WESTERN COLORADO AND A SECOND
OVER EASTERN IDAHO...WHILE ANOTHER SHORTWAVE WAS UPSTREAM OVER THE
ALASKA PANHANDLE. WV IMAGERY AS OF 1 PM CDT...INDICATED SHORTWAVE
ENERGY IN ASSOCIATION WITH THE WAVE OVER WESTERN COLORADO HAD BEGUN
TO EMERGE ACROSS CENTRAL COLORADO AND HAS LED TO INCREASING
CLOUDINESS ALONG THE FRONT RANGE OF COLORADO. OVER THE NEXT COUPLE
OF HRS...SHRAS AND TSRAS ARE EXPECTED TO DEVELOP ON THE LEE SIDE OF
THE ROCKIES INVOF THE FRONT RANGES OF COLORADO AND WYOMING. FURTHER
WEST...A CLOSED LOW REMAINS IN PLACE OVER EASTERN IDAHO ATTM WITH A
BROAD AREA OF CLOUDS AND SHOWERS ACROSS MONTANA...NORTH DAKOTA AND
NORTHERN SOUTH DAKOTA. ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA...ABUNDANT CLOUDINESS WAS PRESENT OVER MOST OF THE AREA
WITH THE EXCEPTION OF FAR SWRN NEBRASKA AND THE EASTERN NEBRASKA
PANHANDLE WHERE CLOUDS HAVE SCATTERED OUT OVER THE PAST 1 TO 2
HOURS. AT THE SURFACE...A TANDEM OF LOW PRESSURE CENTERS WERE
PRESENT ACROSS SERN WYOMING AND A SECOND OVER SOUTH CENTRAL SD. A
WARM FRONT EXTENDED FROM SERN WYOMING INTO EASTERN SOUTH
DAKOTA...WHILE A COLD FRONT EXTENDED SSWD INTO THE CENTRAL ROCKIES.
UNDER PARTLY TO MOSTLY CLOUDY SKIES...TEMPERATURES AS OF 3 PM
CDT...RANGED FROM 72 AT AINSWORTH...TO 82 AT BROKEN BOW.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 313 PM CDT SAT AUG 23 2014
MODELS REMAIN IN GOOD AGREEMENT
WITH THE PROJECTIONS OF A PV ANOMALY LIFTING NORTHEAST FROM FAR
SOUTHWESTERN WYOMING TOWARD THE NORTHERN PLAINS THIS EVENING AND
OVERNIGHT. RECENT OBSERVATIONS INDICATE THAT THE LOW STRATUS IS
DISSIPATING EARLY THIS AFTERNOON...LEADING TO THE EVENTUAL
DESTABILIZATION OF THE LOWER TROPOSPHERE. AS HEIGHTS FALL WITH THE
APPROACH OF THE PV MAX/ATTENDANT COLD FRONT...STORMS ARE ANTICIPATED
TO FORM INVOF OF THE HIGH PLAINS SURFACE LOW/FRONTAL BOUNDARY AND
POSSIBLY DRIFT EAST ACROSS THE SANDHILLS REGION OF NEB OVERNIGHT.
THE LATEST PROJECTIONS FROM THE RAP AND HRRR SHOWS THAT DESPITE THE
MORNING CLOUDS...LOW TO MID LEVEL LAPSE RATES HAVE INCREASED
SOME...YIELDING A WEAKLY UNSTABLE ATMOSPHERE ACROSS WESTERN PORTIONS
OF THE CWA /CONTINUED CLEARING WILL ALLOW FOR FURTHER
DESTABILIZATION/. THE PROJECTED INSTABILITY /UPWARDS TO 1000 J/KG
ML CAPE/ COMBINED WITH 0-6KM BULK SHEAR OF 30KTS OR SO WILL PROMOTE
THE POSSIBILITY OF STRONG TO LOW END SEVERE STORMS THIS EVENING AND
OVERNIGHT. ANOTHER AREA TO WATCH FOR SEVERE STORMS WILL BE ACROSS
NORTH CENTRAL NEBRASKA LATE THIS AFTERNOON AS A SECONDARY WARM FRONT
LIFTS NORTH TOWARD THE SOUTHEAST SOUTH DAKOTA. ABUNDANT INSTABILITY
AND SUFFICIENT SHEAR WOULD PROMOTE RAPID STORM DEVELOPMENT CAPABLE
OF LARGE HAIL AND DAMAGING WIND GUSTS.
THE HEAVY RAIN THREAT WILL BE NOTICEABLY LESS TONIGHT AS BUFR
SOUNDINGS REVEAL A MUCH LESSER INFLUENCE FROM WARM RAIN
PROCESSES...BUT WITH PWATS AT OR SLIGHTLY ABOVE AVERAGE...BRIEF
HEAVY RAINFALL IS STILL POSSIBLE.
THE COLD FRONT CLEARS THE CWA EARLY ON SUNDAY WITH RAIN CHANCES
POSSIBLY LINGERING ACROSS OUR FAR EAST THROUGH 15Z...OTHERWISE A
SLIGHTLY COOLER AIRMASS IS ANTICIPATED WITH HIGHS RANGING FROM THE
MID 70S ACROSS OUR FAR NORTHWEST...TO LOW TO MID 80S SOUTH OF THE
INTERSTATE 80 CORRIDOR. WITH MOISTURE LACKING AND A STABLE AIRMASS
ANTICIPATED SUNDAY AFTERNOON...STORM CHANCES SHOULD BE KEPT AT BAY
UNTIL AT LEAST 00Z MONDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CDT SAT AUG 23 2014
SUNDAY NIGHT THROUGH TUESDAY...THE MAIN FORECASTING
CHALLENGE CONTINUES TO BE PRECIPITATION CHANCES AND THE THREAT FOR
HEAVY RAIN AS A TROUGH AND SEMI STATIONARY FRONTAL BOUNDARY PERSISTS
ACROSS THE CENTRAL ROCKIES AND PLAINS DURING THE PERIOD. FOR SUNDAY
NIGHT...AFTER RELATIVELY QUIET WEATHER CONDS SUNDAY...MID LEVEL WAA
WILL INCREASE ALONG THE FRONT RANGE DURING THE
EVENING...TRANSITIONING EAST ACROSS THE CENTRAL PLAINS OVERNIGHT
SUNDAY NIGHT INTO EARLY MONDAY. AT THE SAME TIME...A NICE H250 JET
STREAK WILL LIFT ACROSS NWRN NEBRASKA INTO SOUTH DAKOTA PLACING
WESTERN AND NORTH CENTRAL NEBRASKA IN THE RIGHT REAR QUAD OF THIS
FEATURE. ENHANCED LIFT ACROSS THE FORECAST AREA...WILL LEAD TO A
SHARP INCREASE IN THE THREAT OF PCPN SUNDAY NIGHT INTO MONDAY. IN
THE LOWER LEVELS...A FRONTAL BOUNDARY WILL BE ANCHORED ACROSS SRN
NEBRASKA SUNDAY NIGHT WITH THE NOSE OF A H85 LOW LEVEL JET
POSITIONED ACROSS SWRN NEBRASKA. INHERITED FCST HAD THE HIGHEST POPS
ACROSS SRN PORTIONS OF THE FORECAST AREA SUNDAY NIGHT INTO MONDAY
MORNING AND APPEARS ON TRACK ATTM. PRECIPITATION CHANCES WILL
DECREASE SOMEWHAT MONDAY AS MID LEVEL FORCING PUSHES EAST INTO THE
MID MISSOURI VALLEY. BY MONDAY NIGHT...ANOTHER STRONG UPPER LEVEL
DISTURBANCE WILL PUSH ACROSS THE CENTRAL PLAINS...LEADING TO
INCREASED CHANCES FOR RAIN MONDAY NIGHT...AS WELL AS TUESDAY NIGHT. LOW
LEVEL EASTERLY WINDS AND ABUNDANT MID AND UPPER LEVEL MOISTURE
TRANSPORT FROM THE SOUTHWEST IN ASSOCIATION WITH HURRICANE MARIE
COULD LEAD TO HEAVY RAIN ACROSS THE CENTRAL PLAINS BEGINNING MONDAY
NIGHT AND POSSIBLY PERSISTING INTO TUESDAY NIGHT. FURTHER SUPPORT
FOR HEAVY RAIN IS EVIDENT IN FCST PWATS RANGING FROM 1.5 TO 2.0
INCHES MONDAY NIGHT THROUGH TUESDAY NIGHT.
WEDNESDAY THROUGH SATURDAY...LINGERING PCPN CHANCES ARE THE MAIN
FORECAST CHALLENGE IN THE LONG RANGE PERIODS. BY WEDNESDAY INTO
THURSDAY...THE PERSISTENT UPPER LEVEL TROUGH ACROSS THE
ROCKIES...WILL CROSS THE CENTRAL PLAINS INTO THE MISSISSIPPI VALLEY.
THE LATEST GFS SOLN IS 24 HRS FASTER COMPARED TO THE ECMWF IN
LIFTING THIS FEATURE EAST OF THE AREA. THE GFS IS DRY AFTER WEDS
WITH THE TROUGH OVER MISSOURI VALLEY BY 12Z THURSDAY...WHILE THE
ECMWF HAS THIS FEATURE OVER THE SAME AREA BY 12Z FRIDAY. INHERITED
FCST WAS DRY WEDS NIGHT AND INTRODUCED POPS FOR THIS PERIOD AS BOTH
MODELS HAVE TRENDED SLOWER. WILL HOLD OFF ON INTRODUCING POPS FOR
THURSDAY FOR NOW AND WAIT FOR THE MODELS TO COME INTO BETTER
AGREEMENT. AFTER UNSEASONABLY COOL HIGHS IN THE 70S FOR WEDNESDAY
AND THURSDAY...HIGHS WILL REBOUND BACK INTO THE 80S FOR THURSDAY AND
FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1236 PM CDT SAT AUG 23 2014
MVFR OR LOWER STRATUS CONTINUES TO IMPACT MOST AREA TERMINALS
EARLY THIS AFTERNOON...BUT THE LATEST NEAR TERM GUIDANCE INDICATES
SOME DISSIPATION BACK TO VFR BY MID TO LATE AFTERNOON FOR MOST
TERMINALS. THUNDERSTORMS ARE ANTICIPATED OVER MUCH OF THE
SANDHILLS REGION THIS EVENING AND OVERNIGHT...FIRST FORMING OVER
THE HIGHER TERRAIN OF WESTERN NEBRASKA...THEN SPREADING NORTHEAST
OVERNIGHT. BRIEF HEAVY RAINFALL...HAIL AND ERRATIC WIND WOULD
ACCOMPANY ANY STORM THAT DEVELOPS. OTHERWISE DRIER AIR TO FOLLOW
THE STORMS SHOULD ALLOW FOR WIDESPREAD VFR THROUGH THE REMAINDER
OF THE 18Z TAF PERIOD.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CLB
SHORT TERM...JACOBS
LONG TERM...CLB
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1238 PM CDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 532 AM CDT SAT AUG 23 2014
STRATUS IS BEING TO DEVELOP EARLY THIS MORNING AND THE HRRR IS
DOING A DECENT JOB WITH THE LOW CLOUD DEPICTION. THE MODEL
INDICATES THE MORE WIDESPREAD LOW CLOUD POTENTIAL PRIMARILY ALONG
AND NORTH OF THE PLATTE RIVER...BUT CIGS ARE ALSO STARTING TO
LOWER FARTHER SOUTH INTO NORTH CENTRAL KANSAS. CONFIDENCE IS NOT
HIGH ON THE DEVELOPMENT OF FOG AS WINDS ARE FARILY STEADY FROM THE
SOUTHEAST. MODELS SUGGEST THE LOW CLOUDS WILL PERSIST FOR AROUND
THREE HOURS OR SO...BREAKING UP BY MID MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM CDT SAT AUG 23 2014
EARLY MORNING CONVECTION WAS LIFTING OUT OF OUR CWA ON THE NOSE
OF THE LLVL AND AS THE WARM FRONTAL BOUNDARY LIFTS NORTHWARD AHEAD
OF AN UPPER LOW EDGING EAST FM IDAHO. SEVERE WEATHER REPORTS FROM
THE EVENING CONVECTION WERE LIMITED HOWEVER RAINFALL WAS
WIDESPREAD WITH SEVERAL LOCATIONS RECEIVING AMOUNTS NEAR OR ABOVE
ONE INCH.
WINDS WILL TRANSITION SOUTHERLY AS THE WARM FRONTAL BOUNDARY LIFTS
INTO THE DAKOTAS TODAY AND A PERIOD OF BREEZY CONDITIONS ARE
FORECAST DURING THE AFTERNOON WITH GUSTS OF 25 TO 30 MPH
POSSIBLE...ESPECIALLY FOR OUR SOUTHEASTERN ZONES. AFTERNOON TEMPS
ARE LOOKING SIMILAR TO THE LAST FEW DAYS WITH HIGHS RANGING FROM THE
UPPER 80S TO THE MID/UPPER 90S...AIDED BY DEEPER MIXING. CANNOT RULE
OUT AN ISOLATED TSTM IN THE AFTN IN WAA AHEAD OF THE UPPER TROUGH
MOVING INTO MT/WY.
UNCERTAINTY EXISTS IN THE CONVECTIVE POTENTIAL TONIGHT AS THE UPPER
LOW EDGES INTO THE WESTERN DAKOTAS AND A COLD FRONTAL BOUNDARY
ADVANCES EASTWARD FM THE HIGH PLAINS AND REACHES OUR WESTERN CWA
PRIOR TO DAYBREAK. WAA AHEAD OF THE FRONT AND CONVERGENCE/DYNAMICS
ALONG THE BAROCLINIC ZONE MAY LEAD TO ISOLATED/SCATTERED STORMS. IF
STORMS DEVELOP...LACK OF GOOD SHEAR AND MARGINAL INSTABILITY SHOULD
LIMIT STORMS FROM BECOMING SEVERE. AS THE COLD FRONT ARRIVES LATE
TONIGHT...DRIER AIR ADVECTS SOUTHEAST BEHIND THE BOUNDARY WITH DPS
DROPPING OFF TO THE 50S BY SUNDAY MORNING IN OUR WESTERN ZONES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM CDT SAT AUG 23 2014
ALOFT: A FAIRLY AMPLIFIED ERN USA RIDGE/WRN USA TROF SUN WILL
GRADUALLY DEAMPLIFY NEXT WEEK AND BECOME PROGRESSIVE. A POTENT
CLOSED LOW WILL WILL BE EJECTING OUT OF THE TROF...CROSSING THE
DAKOTAS SUN. THIS WILL LEAVE A +TILT TROF BEHIND OVER THE WRN USA
MON-TUE. THIS TROF WILL ADVANCE INTO THE PLAINS WED AND THE LAST 2-3
RUNS OF THE EC/GFS/GEM/UKMET ARE IN DECENT AGREEMENT THRU THIS TIME
FRAME. AGREEMENT BREAKS DOWN THU AND WE SAW HINTS OF THIS 24 HRS
AGO. THE GFS KEEPS THE TROF PROGRESSIVE WHILE THE UKMET/EC AND SOME
OF THE PAST 4 GEM CYCLES BREAK THE BASE OF THE TROF OFF FROM THE
WESTERLIES WHICH BECOME RE-ESTABLISHED OVER SRN CANADA. THE GFS
DEVELOPS NW FLOW OVER THE PLAINS WHILE MOST OTHER MODELS HAVE THE
TROF AXIS OVERHEAD.
SURFACE: A COOL FRONT WILL BE CROSSING THE FCST AREA SUN MORNING.
THIS FRONT WILL BECOME STATIONARY ACROSS NRN KS MON AS IT BECOMES
PARALLEL WITH THE FLOW ALOFT. THE SRN FRINGE OF CANADIAN HIGH PRES
WILL BUILD IN MON-TUE. HOWEVER...WITH THE TROF REMAINING TO THE W
THE FRONT WILL BE CONVECTIVELY ACTIVE
HAZARDS: MULTIPLE ROUNDS OF TSTMS APPEAR LIKELY WITH MON NIGHT
CONTINUING AS THE HIGHEST CONFIDENCE. EXCESSIVE RAINFALL COULD BE A
PROBLEM IF THESE TSTM CLUSTERS TRACK OVER SIMILAR AREAS AND WE MAY
SEE HYDRO/FLOODING CONCERNS.
THE DAILY DETAILS...
SUN: WHILE THE BEST LOW-LVL DEWPOINTS WILL BE WHISKED AWAY BY THIS
TIME FRAME...THERE IS A NARROW TONGUE OF 10-12C 850 MB DWPTS ALONG
THE COOL FRONT. A COUPLE OF SHWRS/TSTMS MAY BE ON-GOING JUST NW OF
THE FCST AREA AT DAYBREAK. PRESENT INDICATIONS ARE THAT THEY WILL
DISSIPATE. BY AFTERNOON THIS MOIST TONGUE WILL BE OVER THE SE FRINGE
OF THE FCST AREA...AND COULD SUPPORT DEVELOPMENT A TSTM OR TWO.
SREF MLCAPE 2000-3000 J/KG. DEEP LAYER SHEAR AROUND 25 KTS WILL
SUPPORT SEVERE MULTI-CELL CONVECTIVE MODE.
SUN NIGHT: A LEE-SIDE LOW WILL BECOME ESTABLISHED NEAR PUB IN THE
RIGHT REAR QUADRANT OF AN 80 KT ULJ. THE RESULT WILL BE UPSLOPE
FLOW...THE DEVELOPMENT OF A LLJ AND ENHANCED THETA-E ADVECTION. RICH
850 MB DWPTS WILL ADVECT BACK INTO THE REGION LEADING TO
DESTABILIZATION AND TSTM DEVELOPMENT OVER THE HIGH PLAINS. SOME OF
THIS SHOULD FILTER E INTO THE FCST AREA AFTER MIDNIGHT.
MON: LOTS OF UNCERTAINTY ON TEMPS. DEPENDENT ON THE AMT OF CLOUD
COVER AND LINGERING TSTM ACTIVITY FROM SUN NIGHT. THIS WILL ACT TO
REINFORCE THE FRONT VIA DIFFERENTIAL HEATING. AREAS N OF I-80 COULD
STAY IN THE 70S WHILE N-CNTRL KS WILL BAKE INTO THE MID 90S. ANY
LEFTOVER TSTM ACTIVITY SHOULD WANE DURING THE DAY. CANT RULE OUT AN
ISOLATED LATE DAY TSTM OR TWO.
MON NIGHT: THE MODELS CONT TO ADVERTISE MCS DEVELOPMENT AT THE NOSE
OF THE LLJ. HIGH POPS ARE IN ORDER ESPECIALLY N OF HWY 6.
TUE: PROBABLY A LULL IN TSTM ACTIVITY IN THE WAKE OF THE MCS. AGAIN
TEMPS ARE HIGHLY UNCERTAIN. WITH CONVECTIVELY REINFORCED FRONT STILL
NEAR THE KS-NEB BORDER...LATE DAY TSTM DEVELOPMENT CANT BE RULED
OUT.
WED-THU: FOR WHAT IT`S WORTH POTENTIAL EXISTS FOR MORE TSTMS AND IF
MCS ACTIVITY IS PLACED JUST RIGHT...MULTIPLE EPISODES COULD RESULT
IN EXCESSIVELY HEAVY RAINFALL.
THE 18Z/22 GFS ENSEMBLES SHOW ABOVE NORMAL UNCERTAINTY IN TEMPS WED-
THU. IF THE EC TURNS OUT CORRECT...WE COULD SEE SUBSTANTIAL CLOUD
COVER/STRATUS TRAPPED BENEATH THE FRONT AS THE UPPER TROF MOVES IN.
THE GEM/EC/GFS/DGEX ALL INDICATE POTENTIAL FOR 1 OR BOTH DAYS WITH
DAYTIME TEMPS JAMMED WAYYYY BELOW NORMAL /AS COOL AS UPPER 60S TO
NEAR 70/.
FRI: DRY WITH SEASONABLE TEMPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1235 PM CDT SAT AUG 23 2014
SLOWLY ERODING LOW CLOUDS OUT OF SOUTH CENTRAL NEBRASKA. GRAND
ISLAND PRETTY MUCH IN THE CLEAR IT APPEARS...WHILE KEARNEY MAY
SKIRT WITH SOME SCATTERED AFTERNOON CLOUDS BUT OVERALL TREND
SHOULD BE CLEARING OUT. WINDS WILL CONTINUE TO INCREASE AHEAD
OF DEEPENING LOW LEVEL TROUGH WITH GUSTS OVER 20 MPH NOT UNCOMMON.
PRECIPITATION WHICH DEVELOPS TO THE WEST TONIGHT COULD MOVE INTO
THE AREA LATE IN THE FORECAST...BUT WAS NOT CONFIDENT IN ITS
COVERAGE TO ADD TO FORECAST AT THIS TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...FAY
SHORT TERM...FAY
LONG TERM...HALBLAUB
AVIATION...NOAA/NWS/MORITZ
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1236 PM CDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 408 AM CDT SAT AUG 23 2014
A SURFACE ANALYSIS AT 07Z INDICATED A FRONT DRAPED ACROSS SOUTHERN
SOUTH DAKOTA WHILE ANOTHER WAS DRAPED FROM WEST CENTRAL INTO
NORTHEAST KANSAS. A FAIRLY LARGE MCS WITH EMBEDDED MCVS CONTINUES TO
LIFT FROM EASTERN AND NORTHERN NEBRASKA INTO SOUTH DAKOTA. MOST IF
NOT ALL SHOWER ACTIVITY HAS ENDED FROM SOUTHWEST NEBRASKA INTO THE
CENTRAL SANDHILLS. TEMPERATURES AND DEWPOINTS RANGING IN THE 60S
ACROSS WRN AND NCTRL NEBR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT AUG 23 2014
FOR TODAY...
MODELS ARE IN FAIRLY GOOD AGREEMENT WITH A PV ANOMALY AND MID LEVEL
DISTURBANCE LIFTING NORTHEAST FROM SOUTHERN UTAH CURRENTLY AND INTO
NORTHEAST COLORADO BY 00Z THIS EVENING. ALONG WITH PEAK
HEATING...THIS WILL PROVIDE AN INCREASE TO 30 POPS AFTER 21Z TODAY
ACROSS THE NWRN HALF OF FA AND A SLIGHT CHC TO SOUTHEAST AREAS. A
FAIRLY CLOUDY MORNING BASED ON RAP MODEL TIME SECTION AND LATEST
SATELLITE IMAGERY. AFTERNOON CLEARING TO PARTLY CLOUDY EXPECTED FOR
HIGHS FROM LOW 80S NORTHWEST TO UPPER 80S SOUTHWEST.
FOR TONIGHT...
THE ARW AND NMM MODELS FAVORED WHICH PERFORMED THE BEST WITH CURRENT
SYSTEM EXITING THE AREA. BEST OVERALL PRECIPITATION CHANCES THIS
EVENING WITH SYSTEM PASSAGE ARE 30-50 POPS WEST OF AN IML-ANW LINE
AND 20-30 POPS FOR AREAS EAST. STORM MOTION WILL BE TO THE NORTHEAST
AT 15 KTS. MUCH LESS RISK FOR LOCALLY HEAVY RAINFALL AS SOUNDINGS
INDICATE WARM RAIN PROCESSES NOT OPERATING. NEVERTHELESS AREAS
ACROSS THE WEST THIS EVENING MAY RECEIVE A TENTH TO QUARTER INCH OF
NEW RAINFALL. POPS LOWERING TO 20 PERCENT AFTER MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT AUG 23 2014
AN ACTIVE WEATHER PATTERN WILL BE IN PLACE THROUGH THIS PERIOD
WITH MULTIPLE CHANCES FOR RAIN AND COOLER TEMPERATURES EXPECTED
FOR MUCH OF THE WEEK.
THE UPPER LEVEL LOW NOW OVER IDAHO WILL CONTINUE TO IMPACT THE
FORECAST AREA THROUGH THE FIRST PART OF THIS PERIOD. THE CURRENT
FORECAST REMAINS DRY FOR SUNDAY AS THE MODELS SHOW A LACK OF
MOISTURE ACROSS THE AREA. SEVERAL MODELS ARE INDICATING A NARROW
BAND OF DEVELOPMENT MAINLY ACROSS CENTRAL NEBRASKA ALONG A COLD
FRONT THAT LOOKS TO PUSH ACROSS THE FORECAST AREA DURING THE MORNING
HOURS. THERE WILL BE SOME MID LEVEL SUPPORT AS THE UPPER LEVEL LOW
LIFTS INTO NORTHWEST NORTH DAKOTA...DRAGGING WEAK SHORTWAVE ENERGY
ACROSS THE CENTRAL PLAINS. WILL MONITOR FOR ANOTHER FORECAST CYCLE TO
SEE IF THIS TREND CONTINUES AND IF SO...MAY NEED TO ADD SOME
PRECIPITATION CHANCES FOR PART OF THE DAY SUNDAY. ALSO...A GOOD POOL
OF COLD AIR WILL BE CIRCULATING AROUND THE SYSTEM...WITH MUCH COOLER
AIR BEING DRAWN DOWN INTO NEBRASKA. BY 00Z TUESDAY THE MODELS ARE
LIFTING THE SYSTEM FURTHER NORTH...ALLOWING WARM AIR ADVECTION TO
BEGIN ACROSS THE SOUTH AND WESTERN PARTS OF THE AREA. WITH THE
COOLER TEMPERATURES AND EXPECTING AT LEAST PARTIAL CLOUD COVER THE
FORECAST HIGHS ARE NOW RANGING FROM THE MID 70S TO THE MID 80S.
AN UPPER LEVEL LOW NOW MOVING INTO NORTHWEST CANADA OUT OF THE GULF
OF ALASKA WILL DIG SOUTH INTO THE NORTHWEST PORTION OF THE CONUS BY
MONDAY WHILE THE UPPER LOW TO THE NORTH PUSHES FURTHER NORTH AND
EAST AWAY FROM THE AREA. THIS WILL KEEP THE CENTRAL PLAINS UNDER
SOUTHWEST FLOW TO HELP BRING MOISTURE UP INTO THE AREA THROUGH
MID-WEEK.
FOR SUNDAY NIGHT...THE MODELS CONTINUE TO DEVELOP CONVECTION OVER
NORTHEAST COLORADO...WHICH THEN SPREADS NORTHEAST INTO WESTERN
NEBRASKA. THE AREA WILL BE IN THE FAVORED RIGHT ENTRANCE REGION OF
THE JET AND WITH AN INCREASING LOW LEVEL JET /THOUGH NOT
PARTICULARLY STRONG/ INTO THE EVENING THERE MIGHT BE ENOUGH FORCING
TO KEEP THESE STORMS GOING OVERNIGHT INTO NEBRASKA SO MADE VERY
LITTLE CHANGES TO ONGOING PRECIPITATION FORECAST.
DURING THE DAY MONDAY...ATTEMPTED TO SHOW A TREND OF THIS ACTIVITY
MOVING NORTHEAST AND THROUGH THE FORECAST AREA. MODELS SEEM TO BE
SLOWING THE ADVANCEMENT OF THESE STORMS FROM PRIOR MODEL RUNS SO
DON/T HAVE A HIGH DEGREE OF CONFIDENCE ON THE TIMING NOR PLACEMENT
OF THESE STORM CHANCES.
KEPT LIKELY CHANCES FOR RAIN FOR PORTIONS OF THE FORECAST AREA FOR
MONDAY NIGHT. STILL LOOKS TO BE A SURFACE LOW SOMEWHERE OVER EASTERN
COLORADO/WESTERN KANSAS WITH WARM FRONT EXTENDING INTO CENTRAL AND
NORTHEAST NEBRASKA. THE MODELS ARE IN GOOD AGREEMENT WITH A WEAK
SHORTWAVE TROUGH MOVING OUT OF THE FOUR CORNERS AND ACROSS THE
CENTRAL PLAINS BY 12Z TUESDAY WHILE THE MAIN TROUGH REMAINS OFF TO
THE WEST OVER IDAHO AND NEVADA. THE COMBINATION OF FORCING FROM THE
SHORTWAVE TROUGH MOVING ACROSS THE AREA AND AN INCREASING LOW LEVEL
JET BEING FOCUSED INTO WESTERN NEBRASKA FEEL THAT MONDAY NIGHT HAS
THE HIGHEST CHANCES FOR RAINFALL. COULD BE ANOTHER DAY SIMILAR TO
YESTERDAY WHERE THERE IS ENOUGH SHEAR AND INSTABILITY TO AT LEAST
MENTION A THREAT FOR A FEW SEVERE STORMS...BUT THIS WILL DEPEND ON
CONVECTION DURING THE DAY MONDAY AND WITH PRECIPITABLE WATER VALUES
OVER 120 PERCENT OF NORMAL AND WARM CLOUD DEPTHS EXCEEDING 3500M
STORMS SHOULD BE EFFICIENT RAIN MAKERS SO MAY BE DEALING WITH MORE
OF A HEAVY RAIN THREAT.
TUESDAY THROUGH FRIDAY...THE LONG RANGE MODELS BEGIN TO DIVERGE WITH
HOW THEY HANDLE HOW THE TROUGH TO WEST BEHAVES. THE GFS QUICKLY
PUSHES IT EAST THROUGH THE PLAINS AND INTO THE GREAT LAKES REGION BY
THURSDAY WHILE THE ECMWF AND GEM ARE SLOWER AND DON/T MOVE IT OUT OF
THE CENTRAL PLAINS UNTIL LATER IN THE WEEK. THIS WILL HAVE AN IMPACT
ON THE SENSIBLE WEATHER AS THE SLOWER SOLUTION WOULD LINGER
PRECIPITATION ACROSS THE AREA LONGER...AT LEAST THROUGH
THURSDAY...WHILE THE GFS HAS A DRY FORECAST BY WEDNESDAY MORNING.
HAVE NOT JUMPED ON THE SLOWER SOLUTION BUT DID LEAVE SOME SLIGHT
CHANCES IN THE FORECAST THROUGH THURSDAY. WHAT IS FAIRLY CERTAIN
EITHER WAY IS THAT TEMPERATURES WILL BE COOLER FOR THE WEEK. WITH
PRECIPITATION AND CLOUD COVER...SOME DAYS MAY SEE HIGHS STRUGGLE TO
GET INTO THE LOW AND MID 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1236 PM CDT SAT AUG 23 2014
MVFR OR LOWER STRATUS CONTINUES TO IMPACT MOST AREA TERMINALS
EARLY THIS AFTERNOON...BUT THE LATEST NEAR TERM GUIDANCE INDICATES
SOME DISSIPATION BACK TO VFR BY MID TO LATE AFTERNOON FOR MOST
TERMINALS. THUNDERSTORMS ARE ANTICIPATED OVER MUCH OF THE
SANDHILLS REGION THIS EVENING AND OVERNIGHT...FIRST FORMING OVER
THE HIGHER TERRAIN OF WESTERN NEBRASKA...THEN SPREADING NORTHEAST
OVERNIGHT. BRIEF HEAVY RAINFALL...HAIL AND ERRATIC WIND WOULD
ACCOMPANY ANY STORM THAT DEVELOPS. OTHERWISE DRIER AIR TO FOLLOW
THE STORMS SHOULD ALLOW FOR WIDESPREAD VFR THROUGH THE REMAINDER
OF THE 18Z TAF PERIOD.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROBERG
SHORT TERM...ROBERG
LONG TERM...BROOKS
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
643 AM CDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 408 AM CDT SAT AUG 23 2014
A SURFACE ANALYSIS AT 07Z INDICATED A FRONT DRAPED ACROSS SOUTHERN
SOUTH DAKOTA WHILE ANOTHER WAS DRAPED FROM WEST CENTRAL INTO
NORTHEAST KANSAS. A FAIRLY LARGE MCS WITH EMBEDDED MCVS CONTINUES TO
LIFT FROM EASTERN AND NORTHERN NEBRASKA INTO SOUTH DAKOTA. MOST IF
NOT ALL SHOWER ACTIVITY HAS ENDED FROM SOUTHWEST NEBRASKA INTO THE
CENTRAL SANDHILLS. TEMPERATURES AND DEWPOINTS RANGING IN THE 60S
ACROSS WRN AND NCTRL NEBR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT AUG 23 2014
FOR TODAY...
MODELS ARE IN FAIRLY GOOD AGREEMENT WITH A PV ANOMALY AND MID LEVEL
DISTURBANCE LIFTING NORTHEAST FROM SOUTHERN UTAH CURRENTLY AND INTO
NORTHEAST COLORADO BY 00Z THIS EVENING. ALONG WITH PEAK
HEATING...THIS WILL PROVIDE AN INCREASE TO 30 POPS AFTER 21Z TODAY
ACROSS THE NWRN HALF OF FA AND A SLIGHT CHC TO SOUTHEAST AREAS. A
FAIRLY CLOUDY MORNING BASED ON RAP MODEL TIME SECTION AND LATEST
SATELLITE IMAGERY. AFTERNOON CLEARING TO PARTLY CLOUDY EXPECTED FOR
HIGHS FROM LOW 80S NORTHWEST TO UPPER 80S SOUTHWEST.
FOR TONIGHT...
THE ARW AND NMM MODELS FAVORED WHICH PERFORMED THE BEST WITH CURRENT
SYSTEM EXITING THE AREA. BEST OVERALL PRECIPITATION CHANCES THIS
EVENING WITH SYSTEM PASSAGE ARE 30-50 POPS WEST OF AN IML-ANW LINE
AND 20-30 POPS FOR AREAS EAST. STORM MOTION WILL BE TO THE NORTHEAST
AT 15 KTS. MUCH LESS RISK FOR LOCALLY HEAVY RAINFALL AS SOUNDINGS
INDICATE WARM RAIN PROCESSES NOT OPERATING. NEVERTHELESS AREAS
ACROSS THE WEST THIS EVENING MAY RECEIVE A TENTH TO QUARTER INCH OF
NEW RAINFALL. POPS LOWERING TO 20 PERCENT AFTER MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT AUG 23 2014
AN ACTIVE WEATHER PATTERN WILL BE IN PLACE THROUGH THIS PERIOD
WITH MULTIPLE CHANCES FOR RAIN AND COOLER TEMPERATURES EXPECTED
FOR MUCH OF THE WEEK.
THE UPPER LEVEL LOW NOW OVER IDAHO WILL CONTINUE TO IMPACT THE
FORECAST AREA THROUGH THE FIRST PART OF THIS PERIOD. THE CURRENT
FORECAST REMAINS DRY FOR SUNDAY AS THE MODELS SHOW A LACK OF
MOISTURE ACROSS THE AREA. SEVERAL MODELS ARE INDICATING A NARROW
BAND OF DEVELOPMENT MAINLY ACROSS CENTRAL NEBRASKA ALONG A COLD
FRONT THAT LOOKS TO PUSH ACROSS THE FORECAST AREA DURING THE MORNING
HOURS. THERE WILL BE SOME MID LEVEL SUPPORT AS THE UPPER LEVEL LOW
LIFTS INTO NORTHWEST NORTH DAKOTA...DRAGGING WEAK SHORTWAVE ENERGY
ACROSS THE CENTRAL PLAINS. WILL MONITOR FOR ANOTHER FORECAST CYCLE TO
SEE IF THIS TREND CONTINUES AND IF SO...MAY NEED TO ADD SOME
PRECIPITATION CHANCES FOR PART OF THE DAY SUNDAY. ALSO...A GOOD POOL
OF COLD AIR WILL BE CIRCULATING AROUND THE SYSTEM...WITH MUCH COOLER
AIR BEING DRAWN DOWN INTO NEBRASKA. BY 00Z TUESDAY THE MODELS ARE
LIFTING THE SYSTEM FURTHER NORTH...ALLOWING WARM AIR ADVECTION TO
BEGIN ACROSS THE SOUTH AND WESTERN PARTS OF THE AREA. WITH THE
COOLER TEMPERATURES AND EXPECTING AT LEAST PARTIAL CLOUD COVER THE
FORECAST HIGHS ARE NOW RANGING FROM THE MID 70S TO THE MID 80S.
AN UPPER LEVEL LOW NOW MOVING INTO NORTHWEST CANADA OUT OF THE GULF
OF ALASKA WILL DIG SOUTH INTO THE NORTHWEST PORTION OF THE CONUS BY
MONDAY WHILE THE UPPER LOW TO THE NORTH PUSHES FURTHER NORTH AND
EAST AWAY FROM THE AREA. THIS WILL KEEP THE CENTRAL PLAINS UNDER
SOUTHWEST FLOW TO HELP BRING MOISTURE UP INTO THE AREA THROUGH
MID-WEEK.
FOR SUNDAY NIGHT...THE MODELS CONTINUE TO DEVELOP CONVECTION OVER
NORTHEAST COLORADO...WHICH THEN SPREADS NORTHEAST INTO WESTERN
NEBRASKA. THE AREA WILL BE IN THE FAVORED RIGHT ENTRANCE REGION OF
THE JET AND WITH AN INCREASING LOW LEVEL JET /THOUGH NOT
PARTICULARLY STRONG/ INTO THE EVENING THERE MIGHT BE ENOUGH FORCING
TO KEEP THESE STORMS GOING OVERNIGHT INTO NEBRASKA SO MADE VERY
LITTLE CHANGES TO ONGOING PRECIPITATION FORECAST.
DURING THE DAY MONDAY...ATTEMPTED TO SHOW A TREND OF THIS ACTIVITY
MOVING NORTHEAST AND THROUGH THE FORECAST AREA. MODELS SEEM TO BE
SLOWING THE ADVANCEMENT OF THESE STORMS FROM PRIOR MODEL RUNS SO
DON/T HAVE A HIGH DEGREE OF CONFIDENCE ON THE TIMING NOR PLACEMENT
OF THESE STORM CHANCES.
KEPT LIKELY CHANCES FOR RAIN FOR PORTIONS OF THE FORECAST AREA FOR
MONDAY NIGHT. STILL LOOKS TO BE A SURFACE LOW SOMEWHERE OVER EASTERN
COLORADO/WESTERN KANSAS WITH WARM FRONT EXTENDING INTO CENTRAL AND
NORTHEAST NEBRASKA. THE MODELS ARE IN GOOD AGREEMENT WITH A WEAK
SHORTWAVE TROUGH MOVING OUT OF THE FOUR CORNERS AND ACROSS THE
CENTRAL PLAINS BY 12Z TUESDAY WHILE THE MAIN TROUGH REMAINS OFF TO
THE WEST OVER IDAHO AND NEVADA. THE COMBINATION OF FORCING FROM THE
SHORTWAVE TROUGH MOVING ACROSS THE AREA AND AN INCREASING LOW LEVEL
JET BEING FOCUSED INTO WESTERN NEBRASKA FEEL THAT MONDAY NIGHT HAS
THE HIGHEST CHANCES FOR RAINFALL. COULD BE ANOTHER DAY SIMILAR TO
YESTERDAY WHERE THERE IS ENOUGH SHEAR AND INSTABILITY TO AT LEAST
MENTION A THREAT FOR A FEW SEVERE STORMS...BUT THIS WILL DEPEND ON
CONVECTION DURING THE DAY MONDAY AND WITH PRECIPITABLE WATER VALUES
OVER 120 PERCENT OF NORMAL AND WARM CLOUD DEPTHS EXCEEDING 3500M
STORMS SHOULD BE EFFICIENT RAIN MAKERS SO MAY BE DEALING WITH MORE
OF A HEAVY RAIN THREAT.
TUESDAY THROUGH FRIDAY...THE LONG RANGE MODELS BEGIN TO DIVERGE WITH
HOW THEY HANDLE HOW THE TROUGH TO WEST BEHAVES. THE GFS QUICKLY
PUSHES IT EAST THROUGH THE PLAINS AND INTO THE GREAT LAKES REGION BY
THURSDAY WHILE THE ECMWF AND GEM ARE SLOWER AND DON/T MOVE IT OUT OF
THE CENTRAL PLAINS UNTIL LATER IN THE WEEK. THIS WILL HAVE AN IMPACT
ON THE SENSIBLE WEATHER AS THE SLOWER SOLUTION WOULD LINGER
PRECIPITATION ACROSS THE AREA LONGER...AT LEAST THROUGH
THURSDAY...WHILE THE GFS HAS A DRY FORECAST BY WEDNESDAY MORNING.
HAVE NOT JUMPED ON THE SLOWER SOLUTION BUT DID LEAVE SOME SLIGHT
CHANCES IN THE FORECAST THROUGH THURSDAY. WHAT IS FAIRLY CERTAIN
EITHER WAY IS THAT TEMPERATURES WILL BE COOLER FOR THE WEEK. WITH
PRECIPITATION AND CLOUD COVER...SOME DAYS MAY SEE HIGHS STRUGGLE TO
GET INTO THE LOW AND MID 70S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 642 AM CDT SAT AUG 23 2014
NEAR TERM AVIATION CONCERN IS DURATION OF MVFR CIGS. POTENTIAL FOR
CIGS BKN015-BKN020 FOR BOTH KLBF AND KVTN TERMINALS UNTIL 16Z.
THEREAFTER...ANY CIGS SHOULD LIFT TO VFR AND PERSIST FOR REMAINDER
OF THE PERIOD. DID NOT INCLUDE MENTION OF SHRA OR TSRA. EXPECT
MAIN AREA OF DEVELOPMENT TO BE WEST OF THE TERMINALS AFTER 00Z/24TH.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROBERG
SHORT TERM...ROBERG
LONG TERM...BROOKS
AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
537 AM CDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 532 AM CDT SAT AUG 23 2014
STRATUS IS BEING TO DEVELOP EARLY THIS MORNING AND THE HRRR IS
DOING A DECENT JOB WITH THE LOW CLOUD DEPICTION. THE MODEL
INDICATES THE MORE WIDESPREAD LOW CLOUD POTENTIAL PRIMARILY ALONG
AND NORTH OF THE PLATTE RIVER...BUT CIGS ARE ALSO STARTING TO
LOWER FARTHER SOUTH INTO NORTH CENTRAL KANSAS. CONFIDENCE IS NOT
HIGH ON THE DEVELOPMENT OF FOG AS WINDS ARE FARILY STEADY FROM THE
SOUTHEAST. MODELS SUGGEST THE LOW CLOUDS WILL PERSIST FOR AROUND
THREE HOURS OR SO...BREAKING UP BY MID MORNING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM CDT SAT AUG 23 2014
EARLY MORNING CONVECTION WAS LIFTING OUT OF OUR CWA ON THE NOSE
OF THE LLVL AND AS THE WARM FRONTAL BOUNDARY LIFTS NORTHWARD AHEAD
OF AN UPPER LOW EDGING EAST FM IDAHO. SEVERE WEATHER REPORTS FROM
THE EVENING CONVECTION WERE LIMITED HOWEVER RAINFALL WAS
WIDESPREAD WITH SEVERAL LOCATIONS RECEIVING AMOUNTS NEAR OR ABOVE
ONE INCH.
WINDS WILL TRANSITION SOUTHERLY AS THE WARM FRONTAL BOUNDARY LIFTS
INTO THE DAKOTAS TODAY AND A PERIOD OF BREEZY CONDITIONS ARE
FORECAST DURING THE AFTERNOON WITH GUSTS OF 25 TO 30 MPH
POSSIBLE...ESPECIALLY FOR OUR SOUTHEASTERN ZONES. AFTERNOON TEMPS
ARE LOOKING SIMILAR TO THE LAST FEW DAYS WITH HIGHS RANGING FROM THE
UPPER 80S TO THE MID/UPPER 90S...AIDED BY DEEPER MIXING. CANNOT RULE
OUT AN ISOLATED TSTM IN THE AFTN IN WAA AHEAD OF THE UPPER TROUGH
MOVING INTO MT/WY.
UNCERTAINTY EXISTS IN THE CONVECTIVE POTENTIAL TONIGHT AS THE UPPER
LOW EDGES INTO THE WESTERN DAKOTAS AND A COLD FRONTAL BOUNDARY
ADVANCES EASTWARD FM THE HIGH PLAINS AND REACHES OUR WESTERN CWA
PRIOR TO DAYBREAK. WAA AHEAD OF THE FRONT AND CONVERGENCE/DYNAMICS
ALONG THE BAROCLINIC ZONE MAY LEAD TO ISOLATED/SCATTERED STORMS. IF
STORMS DEVELOP...LACK OF GOOD SHEAR AND MARGINAL INSTABILITY SHOULD
LIMIT STORMS FROM BECOMING SEVERE. AS THE COLD FRONT ARRIVES LATE
TONIGHT...DRIER AIR ADVECTS SOUTHEAST BEHIND THE BOUNDARY WITH DPS
DROPPING OFF TO THE 50S BY SUNDAY MORNING IN OUR WESTERN ZONES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM CDT SAT AUG 23 2014
ALOFT: A FAIRLY AMPLIFIED ERN USA RIDGE/WRN USA TROF SUN WILL
GRADUALLY DEAMPLIFY NEXT WEEK AND BECOME PROGRESSIVE. A POTENT
CLOSED LOW WILL WILL BE EJECTING OUT OF THE TROF...CROSSING THE
DAKOTAS SUN. THIS WILL LEAVE A +TILT TROF BEHIND OVER THE WRN USA
MON-TUE. THIS TROF WILL ADVANCE INTO THE PLAINS WED AND THE LAST 2-3
RUNS OF THE EC/GFS/GEM/UKMET ARE IN DECENT AGREEMENT THRU THIS TIME
FRAME. AGREEMENT BREAKS DOWN THU AND WE SAW HINTS OF THIS 24 HRS
AGO. THE GFS KEEPS THE TROF PROGRESSIVE WHILE THE UKMET/EC AND SOME
OF THE PAST 4 GEM CYCLES BREAK THE BASE OF THE TROF OFF FROM THE
WESTERLIES WHICH BECOME RE-ESTABLISHED OVER SRN CANADA. THE GFS
DEVELOPS NW FLOW OVER THE PLAINS WHILE MOST OTHER MODELS HAVE THE
TROF AXIS OVERHEAD.
SURFACE: A COOL FRONT WILL BE CROSSING THE FCST AREA SUN MORNING.
THIS FRONT WILL BECOME STATIONARY ACROSS NRN KS MON AS IT BECOMES
PARALLEL WITH THE FLOW ALOFT. THE SRN FRINGE OF CANADIAN HIGH PRES
WILL BUILD IN MON-TUE. HOWEVER...WITH THE TROF REMAINING TO THE W
THE FRONT WILL BE CONVECTIVELY ACTIVE
HAZARDS: MULTIPLE ROUNDS OF TSTMS APPEAR LIKELY WITH MON NIGHT
CONTINUING AS THE HIGHEST CONFIDENCE. EXCESSIVE RAINFALL COULD BE A
PROBLEM IF THESE TSTM CLUSTERS TRACK OVER SIMILAR AREAS AND WE MAY
SEE HYDRO/FLOODING CONCERNS.
THE DAILY DETAILS...
SUN: WHILE THE BEST LOW-LVL DEWPOINTS WILL BE WHISKED AWAY BY THIS
TIME FRAME...THERE IS A NARROW TONGUE OF 10-12C 850 MB DWPTS ALONG
THE COOL FRONT. A COUPLE OF SHWRS/TSTMS MAY BE ON-GOING JUST NW OF
THE FCST AREA AT DAYBREAK. PRESENT INDICATIONS ARE THAT THEY WILL
DISSIPATE. BY AFTERNOON THIS MOIST TONGUE WILL BE OVER THE SE FRINGE
OF THE FCST AREA...AND COULD SUPPORT DEVELOPMENT A TSTM OR TWO.
SREF MLCAPE 2000-3000 J/KG. DEEP LAYER SHEAR AROUND 25 KTS WILL
SUPPORT SEVERE MULTI-CELL CONVECTIVE MODE.
SUN NIGHT: A LEE-SIDE LOW WILL BECOME ESTABLISHED NEAR PUB IN THE
RIGHT REAR QUADRANT OF AN 80 KT ULJ. THE RESULT WILL BE UPSLOPE
FLOW...THE DEVELOPMENT OF A LLJ AND ENHANCED THETA-E ADVECTION. RICH
850 MB DWPTS WILL ADVECT BACK INTO THE REGION LEADING TO
DESTABILIZATION AND TSTM DEVELOPMENT OVER THE HIGH PLAINS. SOME OF
THIS SHOULD FILTER E INTO THE FCST AREA AFTER MIDNIGHT.
MON: LOTS OF UNCERTAINTY ON TEMPS. DEPENDENT ON THE AMT OF CLOUD
COVER AND LINGERING TSTM ACTIVITY FROM SUN NIGHT. THIS WILL ACT TO
REINFORCE THE FRONT VIA DIFFERENTIAL HEATING. AREAS N OF I-80 COULD
STAY IN THE 70S WHILE N-CNTRL KS WILL BAKE INTO THE MID 90S. ANY
LEFTOVER TSTM ACTIVITY SHOULD WANE DURING THE DAY. CANT RULE OUT AN
ISOLATED LATE DAY TSTM OR TWO.
MON NIGHT: THE MODELS CONT TO ADVERTISE MCS DEVELOPMENT AT THE NOSE
OF THE LLJ. HIGH POPS ARE IN ORDER ESPECIALLY N OF HWY 6.
TUE: PROBABLY A LULL IN TSTM ACTIVITY IN THE WAKE OF THE MCS. AGAIN
TEMPS ARE HIGHLY UNCERTAIN. WITH CONVECTIVELY REINFORCED FRONT STILL
NEAR THE KS-NEB BORDER...LATE DAY TSTM DEVELOPMENT CANT BE RULED
OUT.
WED-THU: FOR WHAT IT`S WORTH POTENTIAL EXISTS FOR MORE TSTMS AND IF
MCS ACTIVITY IS PLACED JUST RIGHT...MULTIPLE EPISODES COULD RESULT
IN EXCESSIVELY HEAVY RAINFALL.
THE 18Z/22 GFS ENSEMBLES SHOW ABOVE NORMAL UNCERTAINTY IN TEMPS WED-
THU. IF THE EC TURNS OUT CORRECT...WE COULD SEE SUBSTANTIAL CLOUD
COVER/STRATUS TRAPPED BENEATH THE FRONT AS THE UPPER TROF MOVES IN.
THE GEM/EC/GFS/DGEX ALL INDICATE POTENTIAL FOR 1 OR BOTH DAYS WITH
DAYTIME TEMPS JAMMED WAYYYY BELOW NORMAL /AS COOL AS UPPER 60S TO
NEAR 70/.
FRI: DRY WITH SEASONABLE TEMPS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 512 AM CDT SAT AUG 23 2014
CONVECTION HAS DEPARTED THE TERMINALS AND FOR THE MOST PART DRY
WEATHER IS FORECAST. THERE IS AN OUTSIDE CHANCE FOR A STORM OR TWO
DURING THE AFTERNOON AND TONIGHT AHEAD OF AN APPROACHING COLD
FRONT AND UPPER LEVEL TROUGH BUT CHANCES ARE NOT GREAT ENOUGH TO
INCLUDE MENTION IN THE TAFS. THERE MAY BE A BRIEF VSBY RESTRICTION
AROUND DAYBREAK THIS MORNING...BUT VSBYS HAVE BEEN SLOW TO DROP.
OTHERWISE...LOOK FOR SOUTHERLY WINDS TO BE ON THE INCREASE WITH
WIND GUSTS AROUND 25KTS POSSIBLE DURING THE AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...FAY
SHORT TERM...FAY
LONG TERM...HALBLAUB
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
409 AM CDT SAT AUG 23 2014
.SYNOPSIS...
ISSUED AT 408 AM CDT SAT AUG 23 2014
A SURFACE ANALYSIS AT 07Z INDICATED A FRONT DRAPED ACROSS SOUTHERN
SOUTH DAKOTA WHILE ANOTHER WAS DRAPED FROM WEST CENTRAL INTO
NORTHEAST KANSAS. A FAIRLY LARGE MCS WITH EMBEDDED MCVS CONTINUES TO
LIFT FROM EASTERN AND NORTHERN NEBRASKA INTO SOUTH DAKOTA. MOST IF
NOT ALL SHOWER ACTIVITY HAS ENDED FROM SOUTHWEST NEBRASKA INTO THE
CENTRAL SANDHILLS. TEMPERATURES AND DEWPOINTS RANGING IN THE 60S
ACROSS WRN AND NCTRL NEBR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT SAT AUG 23 2014
FOR TODAY...
MODELS ARE IN FAIRLY GOOD AGREEMENT WITH A PV ANOMALY AND MID LEVEL
DISTURBANCE LIFTING NORTHEAST FROM SOUTHERN UTAH CURRENTLY AND INTO
NORTHEAST COLORADO BY 00Z THIS EVENING. ALONG WITH PEAK
HEATING...THIS WILL PROVIDE AN INCREASE TO 30 POPS AFTER 21Z TODAY
ACROSS THE NWRN HALF OF FA AND A SLIGHT CHC TO SOUTHEAST AREAS. A
FAIRLY CLOUDY MORNING BASED ON RAP MODEL TIME SECTION AND LATEST
SATELLITE IMAGERY. AFTERNOON CLEARING TO PARTLY CLOUDY EXPECTED FOR
HIGHS FROM LOW 80S NORTHWEST TO UPPER 80S SOUTHWEST.
FOR TONIGHT...
THE ARW AND NMM MODELS FAVORED WHICH PERFORMED THE BEST WITH CURRENT
SYSTEM EXITING THE AREA. BEST OVERALL PRECIPITATION CHANCES THIS
EVENING WITH SYSTEM PASSAGE ARE 30-50 POPS WEST OF AN IML-ANW LINE
AND 20-30 POPS FOR AREAS EAST. STORM MOTION WILL BE TO THE NORTHEAST
AT 15 KTS. MUCH LESS RISK FOR LOCALLY HEAVY RAINFALL AS SOUNDINGS
INDICATE WARM RAIN PROCESSES NOT OPERATING. NEVERTHELESS AREAS
ACROSS THE WEST THIS EVENING MAY RECEIVE A TENTH TO QUARTER INCH OF
NEW RAINFALL. POPS LOWERING TO 20 PERCENT AFTER MIDNIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 408 AM CDT SAT AUG 23 2014
AN ACTIVE WEATHER PATTERN WILL BE IN PLACE THROUGH THIS PERIOD
WITH MULTIPLE CHANCES FOR RAIN AND COOLER TEMPERATURES EXPECTED
FOR MUCH OF THE WEEK.
THE UPPER LEVEL LOW NOW OVER IDAHO WILL CONTINUE TO IMPACT THE
FORECAST AREA THROUGH THE FIRST PART OF THIS PERIOD. THE CURRENT
FORECAST REMAINS DRY FOR SUNDAY AS THE MODELS SHOW A LACK OF
MOISTURE ACROSS THE AREA. SEVERAL MODELS ARE INDICATING A NARROW
BAND OF DEVELOPMENT MAINLY ACROSS CENTRAL NEBRASKA ALONG A COLD
FRONT THAT LOOKS TO PUSH ACROSS THE FORECAST AREA DURING THE MORNING
HOURS. THERE WILL BE SOME MID LEVEL SUPPORT AS THE UPPER LEVEL LOW
LIFTS INTO NORTHWEST NORTH DAKOTA...DRAGGING WEAK SHORTWAVE ENERGY
ACROSS THE CENTRAL PLAINS. WILL MONITOR FOR ANOTHER FORECAST CYCLE TO
SEE IF THIS TREND CONTINUES AND IF SO...MAY NEED TO ADD SOME
PRECIPITATION CHANCES FOR PART OF THE DAY SUNDAY. ALSO...A GOOD POOL
OF COLD AIR WILL BE CIRCULATING AROUND THE SYSTEM...WITH MUCH COOLER
AIR BEING DRAWN DOWN INTO NEBRASKA. BY 00Z TUESDAY THE MODELS ARE
LIFTING THE SYSTEM FURTHER NORTH...ALLOWING WARM AIR ADVECTION TO
BEGIN ACROSS THE SOUTH AND WESTERN PARTS OF THE AREA. WITH THE
COOLER TEMPERATURES AND EXPECTING AT LEAST PARTIAL CLOUD COVER THE
FORECAST HIGHS ARE NOW RANGING FROM THE MID 70S TO THE MID 80S.
AN UPPER LEVEL LOW NOW MOVING INTO NORTHWEST CANADA OUT OF THE GULF
OF ALASKA WILL DIG SOUTH INTO THE NORTHWEST PORTION OF THE CONUS BY
MONDAY WHILE THE UPPER LOW TO THE NORTH PUSHES FURTHER NORTH AND
EAST AWAY FROM THE AREA. THIS WILL KEEP THE CENTRAL PLAINS UNDER
SOUTHWEST FLOW TO HELP BRING MOISTURE UP INTO THE AREA THROUGH
MID-WEEK.
FOR SUNDAY NIGHT...THE MODELS CONTINUE TO DEVELOP CONVECTION OVER
NORTHEAST COLORADO...WHICH THEN SPREADS NORTHEAST INTO WESTERN
NEBRASKA. THE AREA WILL BE IN THE FAVORED RIGHT ENTRANCE REGION OF
THE JET AND WITH AN INCREASING LOW LEVEL JET /THOUGH NOT
PARTICULARLY STRONG/ INTO THE EVENING THERE MIGHT BE ENOUGH FORCING
TO KEEP THESE STORMS GOING OVERNIGHT INTO NEBRASKA SO MADE VERY
LITTLE CHANGES TO ONGOING PRECIPITATION FORECAST.
DURING THE DAY MONDAY...ATTEMPTED TO SHOW A TREND OF THIS ACTIVITY
MOVING NORTHEAST AND THROUGH THE FORECAST AREA. MODELS SEEM TO BE
SLOWING THE ADVANCEMENT OF THESE STORMS FROM PRIOR MODEL RUNS SO
DON/T HAVE A HIGH DEGREE OF CONFIDENCE ON THE TIMING NOR PLACEMENT
OF THESE STORM CHANCES.
KEPT LIKELY CHANCES FOR RAIN FOR PORTIONS OF THE FORECAST AREA FOR
MONDAY NIGHT. STILL LOOKS TO BE A SURFACE LOW SOMEWHERE OVER EASTERN
COLORADO/WESTERN KANSAS WITH WARM FRONT EXTENDING INTO CENTRAL AND
NORTHEAST NEBRASKA. THE MODELS ARE IN GOOD AGREEMENT WITH A WEAK
SHORTWAVE TROUGH MOVING OUT OF THE FOUR CORNERS AND ACROSS THE
CENTRAL PLAINS BY 12Z TUESDAY WHILE THE MAIN TROUGH REMAINS OFF TO
THE WEST OVER IDAHO AND NEVADA. THE COMBINATION OF FORCING FROM THE
SHORTWAVE TROUGH MOVING ACROSS THE AREA AND AN INCREASING LOW LEVEL
JET BEING FOCUSED INTO WESTERN NEBRASKA FEEL THAT MONDAY NIGHT HAS
THE HIGHEST CHANCES FOR RAINFALL. COULD BE ANOTHER DAY SIMILAR TO
YESTERDAY WHERE THERE IS ENOUGH SHEAR AND INSTABILITY TO AT LEAST
MENTION A THREAT FOR A FEW SEVERE STORMS...BUT THIS WILL DEPEND ON
CONVECTION DURING THE DAY MONDAY AND WITH PRECIPITABLE WATER VALUES
OVER 120 PERCENT OF NORMAL AND WARM CLOUD DEPTHS EXCEEDING 3500M
STORMS SHOULD BE EFFICIENT RAIN MAKERS SO MAY BE DEALING WITH MORE
OF A HEAVY RAIN THREAT.
TUESDAY THROUGH FRIDAY...THE LONG RANGE MODELS BEGIN TO DIVERGE WITH
HOW THEY HANDLE HOW THE TROUGH TO WEST BEHAVES. THE GFS QUICKLY
PUSHES IT EAST THROUGH THE PLAINS AND INTO THE GREAT LAKES REGION BY
THURSDAY WHILE THE ECMWF AND GEM ARE SLOWER AND DON/T MOVE IT OUT OF
THE CENTRAL PLAINS UNTIL LATER IN THE WEEK. THIS WILL HAVE AN IMPACT
ON THE SENSIBLE WEATHER AS THE SLOWER SOLUTION WOULD LINGER
PRECIPITATION ACROSS THE AREA LONGER...AT LEAST THROUGH
THURSDAY...WHILE THE GFS HAS A DRY FORECAST BY WEDNESDAY MORNING.
HAVE NOT JUMPED ON THE SLOWER SOLUTION BUT DID LEAVE SOME SLIGHT
CHANCES IN THE FORECAST THROUGH THURSDAY. WHAT IS FAIRLY CERTAIN
EITHER WAY IS THAT TEMPERATURES WILL BE COOLER FOR THE WEEK. WITH
PRECIPITATION AND CLOUD COVER...SOME DAYS MAY SEE HIGHS STRUGGLE TO
GET INTO THE LOW AND MID 70S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1142 PM CDT FRI AUG 22 2014
TSTMS WILL CONTINUE LIFTING NORTH OVERNIGHT AND EXIT NRN NEB
AROUND 12Z. A PERIOD OF MVFR CIGS MAY DEVELOP IN THE WAKE OF THESE
STORMS BUT THE LATEST INDICATIONS ARE THESE CIGS WOULD NOT LAST
MORE THAN AN HOUR OR TWO BEFORE IMPROVING TO VFR.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ROBERG
SHORT TERM...ROBERG
LONG TERM...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1226 AM CDT SAT AUG 23 2014
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 256 PM CDT FRI AUG 22 2014
THE HIGHLIGHT OF THE SHORT TERM PERIOD WILL BE THE FACT WE ARE
EXPECTING THUNDERSTORMS TODAY/TONIGHT. THERE STILL REMAINS SOME
UNCERTAINTY FOR TIMING...LOCATION...AND OVERALL DEVELOPMENT. THE
WARM FRONT TO OUR SOUTH...WHICH IS SITUATED OVER THE KANSAS/NEBRASKA
BORDER...IS JUST MOSEYING ALONG TODAY AND HAS CAUSED SOME CONCERN
FOR DEVELOPMENT. SHOWERS/STORMS SHOULD DEVELOP ALONG THIS BOUNDARY AS
THE CAP BEGINS TO BREAK. SPC MESOSCALE ANALYSIS PAGE HAS US CAPPED
UNTIL ABOUT 22-23Z. AT THIS TIME WE SHOULD SEE THE BEGINNING STAGES
FOR INITIATION ALONG THE BOUNDARY TO OUR SOUTH. AMPLE INSTABILITY OF
ABOUT 2000-3000 J/KG WILL BE IN PLACE...DUE TO A VERY MOIST BOUNDARY
LAYER AND STEEP LAPSE RATES. MOST UNSTABLE CAPE COULD BE AS HIGH AS
4000 J/KG. BULK SHEAR 0-6 KM WILL BE AROUND 30 KNOTS...AND THIS IS
NOT TOO IMPRESSIVE...HOWEVER...LOW LEVEL SHEAR WILL BE STRONG.
EARLIER RUNS OF THE RAP INDICATED HELICITY VALUES NEAR 400 M2/S2
WOULD BE IN PLACE AROUND 23Z FOR WESTERN PORTIONS OF THE CWA. THESE
VALUES WILL PUSH EASTWARD THROUGH THE AFTERNOON/EVENING. THESE LOW
LEVEL HELICITY VALUES COUPLED WITH AMPLE INSTABILITY WILL POSE A
THREAT FOR SOME ISOLATED TORNADOES...MAINLY FOR OUR NEBRASKA
COUNTIES. WITH THAT BEING...WIND AND HAIL WILL BE THE MAIN THREATS
TODAY/TONIGHT. THE BEST CHANCE FOR SEVERE WEATHER WILL BE ACROSS OUR
NEBRASKA COUNTIES...BUT THE ENTIRE CWA DOES HAVE THE POTENTIAL FOR
SEVERE WEATHER. I DO EXPECT THUNDERSTORM ACTIVITY TO KICK INTO GEAR
AROUND 6 OR 7 PM...IF NOT SOONER.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 256 PM CDT FRI AUG 22 2014
VARIOUS RAIN CHANCES FOR THE WEEKEND AND IN TO THE FIRST PART OF
THE WORK WEEK...ALONG WITH FLUCTUATING TEMPERATURES ARE PRIMARY
FORECAST CONCERNS. WILL KEEP THIS FAIRLY SHORT DUE TO POSSIBLE
SEVERE WEATHER DEVELOPING LATER THIS AFTERNOON.
STARTING OUT SATURDAY EVENING IN THE MID/UPPER LEVELS...THERE SHOULD
BE A LARGE AMPLITUDE TROUGH OVER THE ROCKIES WITH A CLOSED LOW
SITUATED OVER EAST CENTRAL MONTANA...AS THE CURRENT SYSTEM OVER THE
PACIFIC NW DRIFTS EASTWARD. THIS WILL PUSH THE RIDGE A LITTLE EAST
AS WELL WITH THE AXIS STRETCHING FROM LAKE SUPERIOR TO MISSISSIPPI.
THE BETTER FORCING WITH THE LOW PRESSURE SHOULD BE TO THE WEST AND
NORTH OF OUR REGION. AT THE SURFACE...EXPECT A FRONTAL BOUNDARY TO
BE TO OUR NORTH ACROSS SDAK AT 00Z AND THEN THIS WILL PUSH INTO OUR
AREA BY SUNDAY MORNING. HAS NOT TAKEN A WHOLE LOT TO SET OFF
CONVECTION THE PAST WEEK AND WHILE THE SET UP FOR SATURDAY NIGHT IS
NOT AS GOOD AS TONIGHT...WILL PROBABLY STILL NEED SOME LOW POPS
GIVEN APPROACHING WEAK COLD FRONT AND ANTICIPATED LOW LEVEL JET.
PREVIOUS SHIFT AFD NOTED SOME HEAT BURST POTENTIAL WITH ANY
THUNDERSTORMS THAT DO DEVELOP AND THIS SCENARIO STILL IN PLACE.
WEATHER SHOULD BE QUIET DURING THE DAYTIME ON SUNDAY BEHIND THE COLD
FRONT AND POSSIBLE SUNDAY NIGHT ALTHOUGH BOTH THE NAM AND GFS ARE
DEVELOPING SOME PRECIPITATION TO THE WEST AND MOVING ACROSS THE CWA
SUNDAY NIGHT. GFS APPEARS TO OVERDEVELOP A VORTICITY MAX ALTHOUGH
DIFFICULT TO TOTALLY DISCOUNT WITH CYCLONIC FLOW IN UPPER LEVELS.
MONDAY NIGHT AND TUESDAY NIGHT STILL LOOK ACTIVE AS YET ANOTHER HIGH
AMPLITUDE TROUGH IS SLATED TO MOVE ACROSS THE ROCKIES AND INTO THE
PLAINS. AT THE SURFACE AN EAST/WEST STATIONARY FRONT WILL HANG OUT
OVER THE AREA RESULTING IN THE CLASSIC NIGHTTIME RAIN EVENTS. BY
WEDNESDAY THE EXTENDED MODELS IN DECENT AGREEMENT IN PUSHING THE
TROUGH EAST THROUGH THE CWA WITH RIDING THEN MOVING IN TO QUIET
THINGS DOWN FOR THE REMAINDER OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1206 AM CDT SAT AUG 23 2014
SHOWERS AND THUNDERSTORMS WILL LINGER AT THE TERMINALS FOR ANOTHER
HOUR OR SO THEN CONDITIONS WILL DRY OUT BY DAYBREAK. THERE MAY BE
A BRIEF PERIOD OF REDUCED VSBYS IN BR DUE TO THE WET GROUND...BUT
CONFIDENCE IS NOT HIGH FOR DEVELOPMENT OF FOG. LOOK FOR WINDS TO
TRANSITION SOUTHERLY DURING THE DAY WITH WIND SPEEDS INCREASING AS
THE SFC GRADIENT TIGHTENS. WIND GUSTS AROUND 25KTS ARE POSSIBLE.
THERE IS AN OUTSIDE CHC FOR A TSTM BUT CHCS ARE NOT GREAT ENOUGH
TO INCLUDE JUST YET.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...GUERRERO
LONG TERM...EWALD
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1028 PM EDT SUN AUG 24 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXPAND SOUTH ACROSS THE AREA TONIGHT AND
WEDNESDAY...BRINGING COOL AND DRY WEATHER. TROPICAL STORM CRISTOBAL
MAY BECOME A HURRICANE IN THE NEXT FEW DAYS AS IT PASSES SEVERAL
HUNDRED MILES EAST OF THE CAROLINAS. A WARMING TREND WILL DEVELOP
LATE IN THE WEEK. A BACKDOOR FRONT MAY APPROACH BY NEXT
WEEKEND...BRINGING A RISK FOR SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM SUNDAY...ASIDE FROM A FEW PATCHES OF STRATOCUMULUS
NEAR THE BEACHES SKIES ARE CLEAR AND SHOULD REMAIN MOSTLY CLEAR
OVERNIGHT. THE 00Z MHX SOUNDING SHOWED A CLEAR SUBSIDENCE INVERSION
AT 5300 FEET AGL AND MATCHED 18Z MODEL PROJECTIONS CLOSELY. THE ONLY
CHANGE WITH THIS UPDATE WAS TO LOWER DEWPOINT FORECASTS BY A FEW
DEGREES THROUGH THE NIGHT BASED ON CURRENT OBS AND THE 00Z MHX
SOUNDING. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...
AN EXTENSIVE STRATOCUMULUS DECK INLAND IS BEGINNING TO DECAY NOW
THAT THE SUN IS SETTING. SKIES SHOULD BECOME GENERALLY CLEAR
OVERNIGHT AS DRIER AIR ARRIVES IN THE 850 MB LAYER NEAR THE TOP OF
TODAY`S SURFACE MIXED LAYER. BESIDES DOWNWARD ADJUSTMENTS TO SKY
COVER...NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST.
PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
COOL BUT BEAUTIFUL LATE SUMMER AFTERNOON COMING TO AN END...LEAVING
WHAT WILL BE ONE OF THE COOLER NIGHTS THIS AREA HAS SEEN IN QUITE
SOME TIME.
COLD FRONT CONTINUES TO SAG WELL SOUTH OF THE AREA...AND HAS PUSHED
TO NEARLY THE FLORIDA STATE LINE TODAY. DRIVING THIS BOUNDARY IS A
STRONG RIDGE OF HIGH PRESSURE OF CANADIAN ORIGIN...WITH THE CENTER
OF THIS HIGH ACTUALLY WELL NORTH OF WINNIPEG, CANADA IN THE NORTH
CENTRAL PART OF THE COUNTRY. THIS HIGH IS RIDGING INTO NEW ENGLAND
AND THEN DOWN THE EASTERN SEABOARD...WITH ABNORMALLY COOL AND DRY
AIR FOR LATE AUGUST FILTERING INTO THE REGION. THIS AIR MASS IS VERY
FALL-LIKE...AND DEWPOINTS HAVE FALLEN INTO THE LOW AND MID 60S
AREA-WIDE TODAY. THIS DRY AIR HAS LIMITED TOTAL INSTABILITY...AND
ALTHOUGH HIGH-RES GUIDANCE CONTINUES TO SUGGEST THE POTENTIAL FOR
ISOLATED SEA-BREEZE SHOWERS THROUGH THIS EVE...THE CHANCE FOR THAT
IS WANING...AND EVEN DIURNAL CU IS HAVING TROUBLE GAINING MUCH
AGITATION. STILL CONTINUED JUST VERY SCHC ALONG THE SC PORTION OF
THE SEA BREEZE FOR THE NEXT FEW HOURS. IF A SHOWER DOES DEVELOP IT
WILL ERODE QUICKLY AFTER DARK...AS WILL THE MAJORITY OF THE CLOUD
COVER.
NE WINDS WILL REMAIN ELEVATED TONIGHT...LIKELY STAYING 5-10 MPH INTO
MONDAY MORNING. THESE WINDS WILL CONTINUE TO ADVECT COOL/DRY
AIR...THUS DRIVING MINS WELL BELOW 70...WITH LOWER 60S ENCOMPASSING
THE NORTHERN HALF OR 2/3 OF THE CWA. WHILE ELEVATED WINDS TEND TO
LIMIT OVERALL COOLING...NE WINDS HAVE A TENDENCY TO COOL THE AREA
MORE THAN WOULD TYPICALLY BE EXPECTED...ESPECIALLY ACROSS THE CAPE
FEAR REGION. FOR THIS REASON HAVE FORECAST THE LOWEST TEMPS IN THE
NE ZONES TONIGHT...AND WILMINGTON MAY SEE ITS COOLEST NIGHT SINCE
EARLY JUNE.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...THE FORECAST AREA WILL REMAIN IN THE GRIP OF
AN UNSEASONABLE NE FLOW AS HIGH PRESSURE CENTERED ACROSS THE
NORTHEAST U.S. RIDGES SOUTH...WITH ITS AXIS REMAINING TO THE WEST OF
OUR FORECAST AREA. AT THE SAME TIME...SLOW STRENGTHENING OF THE VERY
SLOW MOVING TROPICAL STORM ACROSS THE BAHAMAS IS EXPECTED. THIS WILL
SERVE TO PROLONG THE RATHER TIGHT PRESSURE GRADIENT BETWEEN THESE
TWO SYSTEMS.
AS THESE NE WINDS PERSIST...THEY WILL SERVE TO PILE UP WATER ON THE
IMMEDIATE COAST. THIS IN COMBINATION WITH THE NEW MOON WILL INCREASE
THE RISK FOR MINOR BEACH EROSION FOR THOSE BEACHES EXPOSED TO A NE
FETCH AND MINOR COASTAL FLOODING DURING THE NIGHTTIME HIGH TIDE...
BOTH AT THE BEACHES AND ALONG THE LOWER CAPE FEAR RIVER. OTHER
HAZARDS WILL INCLUDE A STRONG LONG SHORE CURRENT...MODERATE TO
PERHAPS STRONG RIP CURRENTS AND HIGHER THAN NORMAL...ROUGH SURF.
TEMPS WILL BE COOL IN THIS BREEZY NE FLOW REGIME. HIGHS WILL BE
IN THE LOWER TO MID 80S...WITH TUE PERHAPS SLIGHTLY COOLER THAN
MON. LOWS WILL BE IN THE LOWER TO MID 60S WITH PERHAPS UPPER 60S
AT THE BEACHES. WIND SPEEDS ON MON WILL BE UP TO 10 TO 20 MPH WITH
HIGHER GUSTS...ESPECIALLY AT THE BEACHES.
OFFSHORE SHOWERS ARE EXPECTED TO REMAIN THERE FOR MUCH OF THE
PERIOD. TRAJECTORIES WILL AT TIMES BRING THE SHOWERS VERY NEAR THE
BEACHES...BUT GIVEN THE DRYNESS OF THE COLUMN...EXPECT THESE SHOWERS
TO LARGELY ERODE BEFORE MOVING ONSHORE.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...THE MID LEVEL PATTERN WILL SHOW TYPICAL LATE
SUMMER LETHARGY THROUGH THE PERIOD AS RIDGING WILL BE THE CENTRAL
THEME.
THE AXIS OF THE RIDGE MOVES FROM THE MISSISSIPPI VALLEY TO OFF THE
PENINSULA OF FLORIDA BY THE END OF THE PERIOD. AT THE SURFACE...WEAK
HIGH PRESSURE WILL PREVAIL AS WELL AND AS THE MID LEVEL RIDGE
REPOSITIONS...A RELATIVELY WEAK BACKDOOR FRONT WILL MOVE ACROSS
FRIDAY. THIS WILL SERVE TO ENHANCE THE POPS BOTH FRIDAY AND
SATURDAY. HOWEVER MOISTURE AND FORCING REMAIN RELATIVELY WEAK AND
SLIGHT CHANCE FRIDAY TO LOW CHANCE SATURDAY WILL SUFFICE FOR NOW.
THERE IS ALSO SLIGHT CHANCE POPS FOR WEDNESDAY AND THURSDAY ALONG
THE COASTAL AREAS.
THE COOL REFRESHING AIRMASS WILL BE A THING OF THE PAST AS
TEMPERATURES WEDNESDAY THROUGH FRIDAY WILL BE AT OR JUST ABOVE
CLIMATOLOGY. FOR NEXT WEEKEND...A SLIGHT DROP IN TEMPERATURES IS
SEEN AS THE BACKDOOR FRONT MOVES ACROSS BUT JUST A COUPLE OF
DEGREES.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID PERIOD.
CLOUD COVER TODAY HAS BEEN LIMITED TO SCT/BKN 3-6KFT SHALLOW CU
TRAPPED BENEATH AN INVERSION. AS HIGH PRESSURE WEDGES INTO THE
CAROLINAS FROM THE NORTHEAST...DRIER AIR WILL CONTINUE MOVING INTO
OUR AREA TONIGHT THROUGH MON. NORTHEAST WINDS AOB 10 KT TONIGHT WILL
ELIMINATE ANY CHANCE OF VSBY ISSUES. MVFR STRATOCU COULD GRAZE THE
COASTAL TERMS OVERNIGHT...BUT I AM FAIRLY CONFIDENT THAT ANY
PERSISTENT MVFR CIGS WILL REMAIN OFFSHORE. VFR WILL PERSIST INTO MON
AS NORTHEAST WINDS INCREASE TO 10-15 KT WITH GUSTS OF 20 KT DURING
THE DAY.
EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH THE EXTENDED PERIOD.
SLIGHT CHANCE OF SHOWERS ACROSS OUR NORTHERN ZONES FRI.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM SUNDAY...LATEST OBS MATCH OBSERVATIONS VERY CLOSELY.
THE 00Z MHX SOUNDING SHOWED 25 KNOTS THROUGHOUT THE RESIDUAL MIXED
LAYER FROM EARLIER TODAY MATCHING MODEL PROJECTIONS CLOSELY. NO
CHANGES ARE NEEDED TO THE FORECAST. PREVIOUS DISCUSSION FROM 730 PM
FOLLOWS...
WIND SPEEDS ARE RUNNING JUST A BIT HIGHER THAN FORECAST NEARSHORE
BUT LOOK GOOD OFFSHORE COMPARED TO BUOYS 41037 AND 41004. MARINE MOS
GUIDANCE AND LATEST RUC AND HRRR MODELS SUGGEST WIND SPEEDS WILL
BACK MORE NORTHERLY OVERNIGHT BUT WILL NOT DECREASE MUCH IN SPEED.
IN FACT THE ADVECTION OF COOLER AIR OVER THE VERY WARM OCEAN SURFACE
LATER TONIGHT WILL PROBABLY ENHANCE GUSTINESS AND DOWNWARD TRANSPORT
OF STRONGER WINDS FROM ALOFT. NO SIGNIFICANT CHANGES WERE MADE TO
THE FORECAST OVERNIGHT. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
PINCHING NE GRADIENT EAST OF A RIDGE OF HIGH PRESSURE EXPANDING DOWN
THE COAST IS CAUSING DETERIORATING MARINE CONDITIONS TODAY. WINDS
ARE SLOWLY BUT STEADILY RISING OUT OF THE NE...WITH SPEEDS OF 15-20
KTS COMMON ACROSS THE WATERS...WITH SOME GUSTS APPROACHING 30 KTS
DEVELOPING OVER THE NORTHERN WATERS AND OUTSIDE OF 20 NM. AS THE
HIGH PRESSURE STRENGTHENS TONIGHT...THE GRADIENT WILL TIGHTEN
FURTHER...AIDED BY THE DISTANT BUT STRENGTHENING TROPICAL STORM
CRISTOBAL NEAR THE BAHAMAS. THIS WILL CAUSE WIDESPREAD 15-25 KT NE
WINDS THROUGH THE PERIOD...WITH SEAS BUILDING TO 5-8 FT.
WAVE HEIGHTS WILL BE DRIVEN ALMOST ENTIRELY BY A NE WIND CHOP
TONIGHT. HOWEVER...LONGER PERIOD SWELL ASSOCIATED WITH TROPICAL
STORM CRISTOBAL IS FORECAST TO BEGIN TO ENTER THE SPECTRUM TONIGHT.
ONLY NOTICEABLE LONG-SWELL PRESENTLY EXISTS AT 41004 /EDISTO BUOY/
WHICH IS OBSERVING A LOW-AMPLITUDE 13 SEC SWELL. EXPECT THIS TO
GRADUALLY LIFT NE INTO THE LOCAL WATERS...BUT HAVE ONLY MINIMAL
CONTRIBUTION TO THE SIGNIFICANT SEAS UNTIL MONDAY.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...THE PRESSURE DIFFERENCE BETWEEN HIGH PRESSURE
TO THE NORTH AND A SLOWLY DEVELOPING TROPICAL STORM ACROSS THE
BAHAMAS WILL KEEP A TIGHT PRESSURE GRADIENT ACROSS THE WATERS. A
SMALL CRAFT ADVISORY REMAINS IN EFFECT. WINDS WILL COMMONLY BE
SUSTAINED AT 20 TO 25 KT. THE LONG NE FETCH WILL KEEP SEAS IN THE 4
TO 7 FT RANGE WITH AT LEAST 8 FT SEAS BEYOND 20 NM. A 10 TO 12
SECOND SE SWELL IS EXPECTED TO SLOWLY BUILD THROUGH THE PERIOD.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...CONFIDENCE CONTINUES TO BUILD THAT THE ONLY
IMPACTS FROM CRISTOBAL WILL BE THE SWELL COMPONENT ADDED TO THE WAVE
SPECTRUM. THE LATEST WAVEWATCH HURRICANE BULLETIN FOR FRYING PAN
SHOALS SHOWS 7-8 FEET DEVELOPING OR PERSISTING WEDNESDAY THROUGH
EARLY THURSDAY WITH A GOOD PORTION OF THIS BEING THE WIND WAVE
COMPONENT. THIS MAKES SENSE AS THE GFS IS NOT DEVELOPING THE SYSTEM
APPRECIABLY. FOR THE 0-20 MILE COASTAL WATERS 4-6 FEET WEDNESDAY AND
EARLY THURSDAY SHOULD SUFFICE. BY FRIDAY A WEAK PRESSURE PATTERN
YIELDS LIGHT WINDS AND SEAS. FOR THE WINDS WEDNESDAY AND
THURSDAY...A NORTHEASTERLY FLOW OF 10-15 KNOTS WEDNESDAY DROPS TO
SINGLE DIGITS THURSDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 6 PM TO 9 PM EDT THIS EVENING FOR
NCZ106-108.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...JDW/TRA
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
724 PM EDT SUN AUG 24 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXPAND SOUTH ACROSS THE AREA TONIGHT AND
WEDNESDAY...BRINGING COOL AND DRY WEATHER. TROPICAL STORM CRISTOBAL
MAY BECOME A HURRICANE IN THE NEXT FEW DAYS AS IT PASSES SEVERAL
HUNDRED MILES EAST OF THE CAROLINAS. A WARMING TREND WILL DEVELOP
LATE IN THE WEEK. A BACKDOOR FRONT MAY APPROACH BY NEXT
WEEKEND...BRINGING A RISK FOR SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM SUNDAY...AN EXTENSIVE STRATOCUMULUS DECK INLAND IS
BEGINNING TO DECAY NOW THAT THE SUN IS SETTING. SKIES SHOULD BECOME
GENERALLY CLEAR OVERNIGHT AS DRIER AIR ARRIVES IN THE 850 MB LAYER
NEAR THE TOP OF TODAY`S SURFACE MIXED LAYER. BESIDES DOWNWARD
ADJUSTMENTS TO SKY COVER...NO SIGNIFICANT CHANGES HAVE BEEN MADE TO
THE FORECAST. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
COOL BUT BEAUTIFUL LATE SUMMER AFTERNOON COMING TO AN END...LEAVING
WHAT WILL BE ONE OF THE COOLER NIGHTS THIS AREA HAS SEEN IN QUITE
SOME TIME.
COLD FRONT CONTINUES TO SAG WELL SOUTH OF THE AREA...AND HAS PUSHED
TO NEARLY THE FLORIDA STATE LINE TODAY. DRIVING THIS BOUNDARY IS A
STRONG RIDGE OF HIGH PRESSURE OF CANADIAN ORIGIN...WITH THE CENTER
OF THIS HIGH ACTUALLY WELL NORTH OF WINNIPEG, CANADA IN THE NORTH
CENTRAL PART OF THE COUNTRY. THIS HIGH IS RIDGING INTO NEW ENGLAND
AND THEN DOWN THE EASTERN SEABOARD...WITH ABNORMALLY COOL AND DRY
AIR FOR LATE AUGUST FILTERING INTO THE REGION. THIS AIR MASS IS VERY
FALL-LIKE...AND DEWPOINTS HAVE FALLEN INTO THE LOW AND MID 60S
AREA-WIDE TODAY. THIS DRY AIR HAS LIMITED TOTAL INSTABILITY...AND
ALTHOUGH HIGH-RES GUIDANCE CONTINUES TO SUGGEST THE POTENTIAL FOR
ISOLATED SEA-BREEZE SHOWERS THROUGH THIS EVE...THE CHANCE FOR THAT
IS WANING...AND EVEN DIURNAL CU IS HAVING TROUBLE GAINING MUCH
AGITATION. STILL CONTINUED JUST VERY SCHC ALONG THE SC PORTION OF
THE SEA BREEZE FOR THE NEXT FEW HOURS. IF A SHOWER DOES DEVELOP IT
WILL ERODE QUICKLY AFTER DARK...AS WILL THE MAJORITY OF THE CLOUD
COVER.
NE WINDS WILL REMAIN ELEVATED TONIGHT...LIKELY STAYING 5-10 MPH INTO
MONDAY MORNING. THESE WINDS WILL CONTINUE TO ADVECT COOL/DRY
AIR...THUS DRIVING MINS WELL BELOW 70...WITH LOWER 60S ENCOMPASSING
THE NORTHERN HALF OR 2/3 OF THE CWA. WHILE ELEVATED WINDS TEND TO
LIMIT OVERALL COOLING...NE WINDS HAVE A TENDENCY TO COOL THE AREA
MORE THAN WOULD TYPICALLY BE EXPECTED...ESPECIALLY ACROSS THE CAPE
FEAR REGION. FOR THIS REASON HAVE FORECAST THE LOWEST TEMPS IN THE
NE ZONES TONIGHT...AND WILMINGTON MAY SEE ITS COOLEST NIGHT SINCE
EARLY JUNE.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...THE FORECAST AREA WILL REMAIN IN THE GRIP OF
AN UNSEASONABLE NE FLOW AS HIGH PRESSURE CENTERED ACROSS THE
NORTHEAST U.S. RIDGES SOUTH...WITH ITS AXIS REMAINING TO THE WEST OF
OUR FORECAST AREA. AT THE SAME TIME...SLOW STRENGTHENING OF THE VERY
SLOW MOVING TROPICAL STORM ACROSS THE BAHAMAS IS EXPECTED. THIS WILL
SERVE TO PROLONG THE RATHER TIGHT PRESSURE GRADIENT BETWEEN THESE
TWO SYSTEMS.
AS THESE NE WINDS PERSIST...THEY WILL SERVE TO PILE UP WATER ON THE
IMMEDIATE COAST. THIS IN COMBINATION WITH THE NEW MOON WILL INCREASE
THE RISK FOR MINOR BEACH EROSION FOR THOSE BEACHES EXPOSED TO A NE
FETCH AND MINOR COASTAL FLOODING DURING THE NIGHTTIME HIGH TIDE...
BOTH AT THE BEACHES AND ALONG THE LOWER CAPE FEAR RIVER. OTHER
HAZARDS WILL INCLUDE A STRONG LONG SHORE CURRENT...MODERATE TO
PERHAPS STRONG RIP CURRENTS AND HIGHER THAN NORMAL...ROUGH SURF.
TEMPS WILL BE COOL IN THIS BREEZY NE FLOW REGIME. HIGHS WILL BE
IN THE LOWER TO MID 80S...WITH TUE PERHAPS SLIGHTLY COOLER THAN
MON. LOWS WILL BE IN THE LOWER TO MID 60S WITH PERHAPS UPPER 60S
AT THE BEACHES. WIND SPEEDS ON MON WILL BE UP TO 10 TO 20 MPH WITH
HIGHER GUSTS...ESPECIALLY AT THE BEACHES.
OFFSHORE SHOWERS ARE EXPECTED TO REMAIN THERE FOR MUCH OF THE
PERIOD. TRAJECTORIES WILL AT TIMES BRING THE SHOWERS VERY NEAR THE
BEACHES...BUT GIVEN THE DRYNESS OF THE COLUMN...EXPECT THESE SHOWERS
TO LARGELY ERODE BEFORE MOVING ONSHORE.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...THE MID LEVEL PATTERN WILL SHOW TYPICAL LATE
SUMMER LETHARGY THROUGH THE PERIOD AS RIDGING WILL BE THE CENTRAL
THEME.
THE AXIS OF THE RIDGE MOVES FROM THE MISSISSIPPI VALLEY TO OFF THE
PENINSULA OF FLORIDA BY THE END OF THE PERIOD. AT THE SURFACE...WEAK
HIGH PRESSURE WILL PREVAIL AS WELL AND AS THE MID LEVEL RIDGE
REPOSITIONS...A RELATIVELY WEAK BACKDOOR FRONT WILL MOVE ACROSS
FRIDAY. THIS WILL SERVE TO ENHANCE THE POPS BOTH FRIDAY AND
SATURDAY. HOWEVER MOISTURE AND FORCING REMAIN RELATIVELY WEAK AND
SLIGHT CHANCE FRIDAY TO LOW CHANCE SATURDAY WILL SUFFICE FOR NOW.
THERE IS ALSO SLIGHT CHANCE POPS FOR WEDNESDAY AND THURSDAY ALONG
THE COASTAL AREAS.
THE COOL REFRESHING AIRMASS WILL BE A THING OF THE PAST AS
TEMPERATURES WEDNESDAY THROUGH FRIDAY WILL BE AT OR JUST ABOVE
CLIMATOLOGY. FOR NEXT WEEKEND...A SLIGHT DROP IN TEMPERATURES IS
SEEN AS THE BACKDOOR FRONT MOVES ACROSS BUT JUST A COUPLE OF
DEGREES.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID PERIOD.
CLOUD COVER TODAY HAS BEEN LIMITED TO SCT/BKN 3-6KFT SHALLOW CU
TRAPPED BENEATH AN INVERSION. AS HIGH PRESSURE WEDGES INTO THE
CAROLINAS FROM THE NORTHEAST...DRIER AIR WILL CONTINUE MOVING INTO
OUR AREA TONIGHT THROUGH MON. NORTHEAST WINDS AOB 10 KT TONIGHT WILL
ELIMINATE ANY CHANCE OF VSBY ISSUES. MVFR STRATOCU COULD GRAZE THE
COASTAL TERMS OVERNIGHT...BUT I AM FAIRLY CONFIDENT THAT ANY
PERSISTENT MVFR CIGS WILL REMAIN OFFSHORE. VFR WILL PERSIST INTO MON
AS NORTHEAST WINDS INCREASE TO 10-15 KT WITH GUSTS OF 20 KT DURING
THE DAY.
EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH THE EXTENDED PERIOD.
SLIGHT CHANCE OF SHOWERS ACROSS OUR NORTHERN ZONES FRI.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM SUNDAY...WIND SPEEDS ARE RUNNING JUST A BIT HIGHER THAN
FORECAST NEARSHORE BUT LOOK GOOD OFFSHORE COMPARED TO BUOYS 41037
AND 41004. MARINE MOS GUIDANCE AND LATEST RUC AND HRRR MODELS
SUGGEST WIND SPEEDS WILL BACK MORE NORTHERLY OVERNIGHT BUT WILL NOT
DECREASE MUCH IN SPEED. IN FACT THE ADVECTION OF COOLER AIR OVER THE
VERY WARM OCEAN SURFACE LATER TONIGHT WILL PROBABLY ENHANCE
GUSTINESS AND DOWNWARD TRANSPORT OF STRONGER WINDS FROM ALOFT. NO
SIGNIFICANT CHANGES WERE MADE TO THE FORECAST OVERNIGHT. PREVIOUS
DISCUSSION FROM 300 PM FOLLOWS...
PINCHING NE GRADIENT EAST OF A RIDGE OF HIGH PRESSURE EXPANDING DOWN
THE COAST IS CAUSING DETERIORATING MARINE CONDITIONS TODAY. WINDS
ARE SLOWLY BUT STEADILY RISING OUT OF THE NE...WITH SPEEDS OF 15-20
KTS COMMON ACROSS THE WATERS...WITH SOME GUSTS APPROACHING 30 KTS
DEVELOPING OVER THE NORTHERN WATERS AND OUTSIDE OF 20 NM. AS THE
HIGH PRESSURE STRENGTHENS TONIGHT...THE GRADIENT WILL TIGHTEN
FURTHER...AIDED BY THE DISTANT BUT STRENGTHENING TROPICAL STORM
CRISTOBAL NEAR THE BAHAMAS. THIS WILL CAUSE WIDESPREAD 15-25 KT NE
WINDS THROUGH THE PERIOD...WITH SEAS BUILDING TO 5-8 FT.
WAVE HEIGHTS WILL BE DRIVEN ALMOST ENTIRELY BY A NE WIND CHOP
TONIGHT. HOWEVER...LONGER PERIOD SWELL ASSOCIATED WITH TROPICAL
STORM CRISTOBAL IS FORECAST TO BEGIN TO ENTER THE SPECTRUM TONIGHT.
ONLY NOTICEABLE LONG-SWELL PRESENTLY EXISTS AT 41004 /EDISTO BUOY/
WHICH IS OBSERVING A LOW-AMPLITUDE 13 SEC SWELL. EXPECT THIS TO
GRADUALLY LIFT NE INTO THE LOCAL WATERS...BUT HAVE ONLY MINIMAL
CONTRIBUTION TO THE SIGNIFICANT SEAS UNTIL MONDAY.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...THE PRESSURE DIFFERENCE BETWEEN HIGH PRESSURE
TO THE NORTH AND A SLOWLY DEVELOPING TROPICAL STORM ACROSS THE
BAHAMAS WILL KEEP A TIGHT PRESSURE GRADIENT ACROSS THE WATERS. A
SMALL CRAFT ADVISORY REMAINS IN EFFECT. WINDS WILL COMMONLY BE
SUSTAINED AT 20 TO 25 KT. THE LONG NE FETCH WILL KEEP SEAS IN THE 4
TO 7 FT RANGE WITH AT LEAST 8 FT SEAS BEYOND 20 NM. A 10 TO 12
SECOND SE SWELL IS EXPECTED TO SLOWLY BUILD THROUGH THE PERIOD.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...CONFIDENCE CONTINUES TO BUILD THAT THE ONLY
IMPACTS FROM CRISTOBAL WILL BE THE SWELL COMPONENT ADDED TO THE WAVE
SPECTRUM. THE LATEST WAVEWATCH HURRICANE BULLETIN FOR FRYING PAN
SHOALS SHOWS 7-8 FEET DEVELOPING OR PERSISTING WEDNESDAY THROUGH
EARLY THURSDAY WITH A GOOD PORTION OF THIS BEING THE WIND WAVE
COMPONENT. THIS MAKES SENSE AS THE GFS IS NOT DEVELOPING THE SYSTEM
APPRECIABLY. FOR THE 0-20 MILE COASTAL WATERS 4-6 FEET WEDNESDAY AND
EARLY THURSDAY SHOULD SUFFICE. BY FRIDAY A WEAK PRESSURE PATTERN
YIELDS LIGHT WINDS AND SEAS. FOR THE WINDS WEDNESDAY AND
THURSDAY...A NORTHEASTERLY FLOW OF 10-15 KNOTS WEDNESDAY DROPS TO
SINGLE DIGITS THURSDAY.
&&
.TIDES/COASTAL FLOODING...
AS OF 300 PM SUNDAY...RIDGE OF HIGH PRESSURE EXPANDING DOWN THE
COAST IS DRIVING A PINCHED GRADIENT...AND FORCING A LONG PERIOD OF
GUSTY NE WINDS LOCALLY. THESE WINDS ARE FORCING WATER TO "PILE UP"
NEAR THE COASTLINE...AS NOTED BY TIDAL ANOMALIES OF 1 TO 2 FEET AT
THE LOCAL BEACHES. THIS FORCING COMBINED WITH ASTRONOMICAL HIGH
TIDES DUE TO THE APPROACH OF THE NEW MOON (NEW MOON IS
MONDAY)...WILL CAUSE HIGH TIDE LEVELS THIS EVENING TO APPROACH OR
SLIGHTLY EXCEED MINOR FLOOD THRESHOLDS ON THE EAST FACING BEACHES
NORTH OF CAPE FEAR. HIGH TIDE IS AROUND 730 PM AT WRIGHTSVILLE
BEACH...AND A COASTAL FLOOD ADVISORY HAS BEEN ISSUED...VALID FROM
6PM TO 9PM. THE EAST FACING BEACHES OF SC WILL FARE SLIGHTLY
BETTER DUE TO THE COASTLINE ORIENTATION WITH RESPECT TO WIND
DIRECTION...AND THUS SHOULD STAY BELOW MINOR FLOOD THRESHOLDS
TONIGHT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 6 PM TO 9 PM EDT THIS EVENING FOR
NCZ106-108.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...JDW/TRA
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...BJR
TIDES/COASTAL FLOODING...JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
351 PM EDT SAT AUG 23 2014
.SYNOPSIS...
A COLD FRONT TO OUR SOUTH WILL BE MOVING AWAY FROM THE AREA BY
SUNDAY MORNING. PROGRESSIVELY DRIER AND COOLER AIR WILL BE PUSHING
SOUTH IN THE WAKE OF THE FRONT AND THIS WILL ALLOW FOR FAR FEWER
SHOWERS AND THUNDERSTORMS SUNDAY. HIGH PRESSURE WILL EXPAND SOUTH
ACROSS THE AREA NEXT WEEK WITH ITS INFLUENCE BEGINNING TO WANE
DURING THE MIDDLE AND LATER PORTIONS OF NEXT WEEK. WE WILL BE
MONITORING FOR THE DEVELOPMENT OF TROPICAL CYCLONE CRISTOBAL IN
THE COMING DAYS. CRISTOBAL MAY MAKE ITS CLOSEST APPROACH TO THE
CAROLINA COAST MID OR LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 300 PM SATURDAY...SHOWERS AND THUNDERSTORMS BEGINNING TO
BECOME MORE WIDESPREAD ACROSS THE AREA...IN A TREND THAT WILL
LIKELY CONTINUE INTO TONIGHT.
THE CWA IS BISECTED THIS AFTERNOON BY A COLD FRONT...WHICH IS
ALIGNED ROUGHLY FROM MYRTLE BEACH...TO FLORENCE...AND UP TOWARDS
CHARLOTTE. THIS BOUNDARY AT THE SURFACE IS DIFFICULT TO IDENTIFY DUE
TO THE LIGHT GRADIENT SURROUNDING IT KEEPING WINDS LIGHT...BUT WINDS
NORTH OF THE BOUNDARY ARE PRIMARILY FROM THE NORTH...WITH VARIABLE
DIRECTIONS TO THE SOUTH. ALOFT...FRONT IS MORE EASILY IDENTIFIABLE
ON PW IMAGERY...AS MUCH DRIER AIR IS FILTERING IN BEHIND THE FRONT.
IT IS INTERESTING TO NOTE...HOWEVER...THAT CONVECTION IS BECOMING
WIDESPREAD IN THE DRIER COLUMN NORTH OF THE BOUNDARY. ALTHOUGH THIS
SEEMS TO BE COUNTER-INTUITIVE...THE BLENDED/LAYERED PWAT PRODUCT FROM
CIRA SHOWS THE DRY AIR CONFINED TO THE LAYER ABOVE 700MB...WHILE
MOISTURE IS ACTUALLY INCREASING BELOW 850MB. THIS WILL CONTINUE TO
BE THE CASE THROUGH TONIGHT AS EVIDENCED BY BOTH RUC AND NAM
FORECAST PROFILES SHOWING PWATS INCREASING TO WELL ABOVE 2 INCHES
THIS EVENING AND TONIGHT...BEFORE DRYING OCCURS LATE.
TRYING TO DETERMINE WHERE CONVECTION WILL BE MOST WIDESPREAD TODAY
IS TRICKY...BUT HIGH RES ARW/NAM/HRRR ALL SUGGEST THE BEST FOCUS
WILL BE ACROSS NC COUNTIES THROUGH THE EVE...WITH LESSER CHANCES IN
SC. THIS IS LIKELY DUE TO A SHORTWAVE WHICH IS PROGGED TO DROP
ACROSS THE AREA...DIRECTED ON NW FLOW BETWEEN A TROUGH OVER NEW
ENGLAND A RIDGE ACROSS THE MS VLY. AS THIS IMPULSE MOVES
OVERHEAD...IT WILL TAP INTO AN ENVIRONMENT CHARACTERIZED BY STRONG
THETA-E RIDGING AND MLCAPE OVER 2000 J/KG. HAVE ATTEMPTED TO TIME
THE HIGHEST POP TO CORRELATE WITH DEEPEST FORECAST-SOUNDING
SATURATION AND THE HIGH RES GUIDANCE...BUT AT LEAST SCT CONVECTION
WILL LIKELY BE ONGOING FOR A MANY-HOUR PERIOD...CENTERED AROUND 7PM.
THIS SUGGESTS THAT SHOWERS WILL PERSIST SEVERAL HOURS AFTER
NIGHTFALL THANKS TO THE FORCING ALOFT...AND HAVE POP WANING AFTER
MIDNIGHT. WHILE SEVERE IS NOT ANTICIPATED...ESPECIALLY WITH THE
DRYING OCCURRING ALOFT AND SOME CONFLUENCE WITHIN THE EXIT REGION OF
AN UPPER JET MOVING NEARBY...ISOLATED GUSTY WINDS ARE POSSIBLE AS IS
TYPICAL WITH NW FLOW EVENTS. HEAVY RAINFALL WILL BE THE PRIMARY
THREAT THROUGH THE PERIOD HOWEVER.
THE FRONT WILL FINALLY GET KICKED SOUTH TONIGHT...AND SHOULD CLEAR
THE CWA BY DAYBREAK SUNDAY. A DEVELOPING NE SURGE BEHIND THE
BOUNDARY WILL HELP DRIVE THIS FRONT SOUTH...BUT ANY COOL ADVECTION
WILL BE A BIT LATE TO SIGNIFICANTLY AFFECT MINS TONIGHT. HAVE SIDED
CLOSELY WITH THE MET NUMBERS WHICH HAVE PERFORMED QUITE WELL THE
PAST FEW NIGHTS...AND LOWS WILL DROP TO AROUND 70 IN THE FAR
NORTH...TO NEAR 75 ALONG THE SOUTHERN GRAND STRAND.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...A COLD FRONT WILL HAVE MOVED THROUGH THE
ENTIRE FORECAST AREA BEFORE 12Z SUN. THE INFLUX OF DRIER AIR WILL
BE STRONGEST AND DEEPEST ACROSS THE NORTHERN ZONES SUN. THE DRY
AIR WILL BE ESPECIALLY PRONOUNCED IN THE MID LEVELS...ABOVE 10-12
KFT. AN ONSHORE FLOW BELOW 10 KFT WILL KEEP THE LOWER LEVELS OF
THE COLUMN MORE MOIST. A SHORTWAVE PUSHING DOWN THE SOUTHEAST
COAST MAY TOUCH OFF SOME SHALLOWER CONVECTION. WILL CARRY A SLIGHT
CHANCE TO SMALL CHANCE OF SHOWERS AND THUNDERSTORMS ON SUNDAY WITH
THE RISK DECREASING FROM NORTH TO SOUTH AS THE DAY PROGRESSES.
PRECIPITABLE WATER VALUES WILL BE DROPPING BELOW THREE-QUARTERS OF
AN INCH SUN NIGHT AS MUCH DRIER AIR OVERWHELMS THE COLUMN DOWN TO
THE SURFACE. THUS...WILL NOT CARRY ANY POPS BEYOND NIGHTFALL. A DEEP
AND TIGHTENING NE FLOW WILL BE PRESENT MON AND MON NIGHT AS A WEDGE
OF HIGH PRESSURE BUILDS STRONGLY ACROSS WESTERN NORTH CAROLINA AND
THE UPSTATE OF SOUTH CAROLINA. AT THE SAME TIME...DEVELOPING
TROPICAL LOW PRESSURE ACROSS THE BAHAMAS WILL RESULT IN A TIGHTENING
PRESSURE GRADIENT. AN INVERTED TROUGH MAY BEGIN TO DEVELOP DURING
THIS TIME AND IF IT COMES CLOSE ENOUGH TO THE COAST...A FEW SHOWERS
MAY IMPINGE ONTO THE COAST. AT THIS TIME...WILL KEEP ANY MENTION OF
CONVECTION OFFSHORE...BUT SHOW SOME INCREASING CLOUD COVER AS
THE COLUMN DOES BEGIN TO MOISTEN BACK UP IN THE LOWER LEVELS.
HIGH TEMPS WILL BE MAINLY NEAR TO A FEW DEGREES BELOW NORMAL THIS
PERIOD AS WE WILL BE UNDER A NE FLOW REGIME. HIGHS BOTH DAYS WILL BE
IN THE MID AND UPPER 80S. DEWPOINTS WILL ALSO BE CONSIDERABLY LOWER
THAN RECENT DAYS AND SO FOR MOST...IT WILL BE MUCH MORE PLEASANT.
LOWS WILL BE BELOW NORMAL AND MAINLY IN THE MID TO UPPER 60S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...THE EXTENDED CONTINUES TO BE DOMINATED BY MID LEVEL
HIGH PRESSURE MOVING FROM THE MISSISSIPPI VALLEY TO THE SOUTHEAST BY
NEXT WEEKEND. AT THE SURFACE HIGH PRESSURE WILL BE THE MAIN FEATURE
FOR TUESDAY AND WEDNESDAY WITH A COOL NORTHEAST FLOW. THE HIGH
BECOMES MORE DIFFUSE THURSDAY...A LITTLE EARLIER THAN PREVIOUS
GUIDANCE. THE SYSTEM FOR LATE IN THE WEEK LOOKS CONSIDERABLY WEAKER
AS WELL. CHANGES TO THE FORECAST THIS AFTERNOON ARE MINIMAL. I DID
INCREASE POPS FOR FRIDAY AND SATURDAY TO MATCH OTHER OFFICES BETTER
BUT THE VALUES ARE STILL LOWER THAN THIS TIME YESTERDAY. THE
TEMPERATURE FORECAST HAS INCREASED ESPECIALLY FOR THURSDAY AND
FRIDAY WITH READINGS NEARING OR EVEN EXCEEDING CLIMATOLOGY SLIGHTLY
FOR THESE PERIODS INCLUDING SATURDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...A COLD FRONT WAS LOCATED IN THE VICINITY OF THE
TERMINALS THIS AFTERNOON. ISOLATED SHOWERS WERE DEVELOPING ALONG
THE SEA BREEZE AND MAY IMPACT ILM/CRE/MYR DURING THE NEXT FEW
HOURS.
THE FRONT WILL SHIFT SOUTH OF ALL TERMINALS TONIGHT. OTHER THAN
SCATTERED THUNDERSTORMS ALONG THE SEA BREEZE...CONVECTION WILL BE
ISOLATED THIS AFTERNOON. HOWEVER...AN UPPER IMPULSE WILL MOVE
TOWARDS THE AREA THIS EVENING...WHICH WILL SET OFF MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS ACROSS THE AREA. STILL SOME UNCERTAINTY
INTO THE TIMING AND COVERAGE OF THIS ACTIVITY...BUT HAVE ENOUGH
CONFIDENCE TO KEEP VCSH AT THE TERMINALS UNTIL AFTER MIDNIGHT. LIGHT
WINDS THIS AFTN WILL BE PRIMARILY FROM THE EAST...WITH MINOR
FLUCTUATIONS TO SE OR NE AT TIMES.
HEAVIEST SHOWERS SHOULD END N-S TONIGHT. POST FRONTAL MVFR CIGS ARE
EXPECTED WITH REASONABLE CONFIDENCE OF POST-FRONTAL IFR AT KFLO/KLBT
OVERNIGHT. MVFR SHORTLY AFTER SUNRISE SHOULD IMPROVE TO VFR AT THE
NORTHERN AND COASTAL TERMINALS INITIALLY...AND KFLO BY MID MORNING.
WINDS WILL BECOME PREDOMINATELY NE 10-15 KT AFTER SUNRISE.
EXTENDED OUTLOOK...EXPECT VFR/NSW TO PREVAIL THROUGH TUES AS HIGH
PRESSURE RIDGES OVER THE EAST COAST IN THE WAKE OF THE COLD FRONT.
A CHANCE OF SHRA WED. VFR/NSW THURS.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM SATURDAY...COLD FRONT IS SLOWLY DROPPING SOUTH ACROSS
THE WATERS TODAY...AND ALTHOUGH IS TOUGH TO LOCATE EXACTLY...APPEARS
TO BE JUST SOUTH OF MYRTLE BEACH AT THIS TIME. THE WATERS NORTH OF
THIS BOUNDARY ARE EXPERIENCING E/NE WINDS OF 5-10 KTS...WHILE SOUTH
OF THE FRONT WINDS ARE LIGHT AND VARIABLE. THE EXCEPTION IS ACROSS
AMZ250 WHERE WINDS ARE GUSTING UP TO 15 KTS FROM THE NE...THE
BEGINNING OF WHAT WILL BE AN INCREASING SURGE TONIGHT. THIS FRONT
WILL SLOWLY DROP THROUGH ALL THE WATERS OVERNIGHT...LEAVING
INCREASING NE WINDS IN ITS WAKE...AND BY SUNDAY MORNING WINDS WILL
BE NE AT 15-20 KTS ACROSS ALL THE WATERS. WAVE HEIGHTS WILL BUILD ON
THESE RISING WINDS...SLOWLY AT FIRST TO 2-3 FT TONIGHT...BUT MORE
QUICKLY LATE...AND WILL BECOME 3-4 FT WITH A FEW 5 FTERS IN THE
NORTHERN WATERS BY SUNDAY MORNING.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...THE GRADIENT WILL BE TIGHTENING UP DURING
THIS PERIOD. A NE SURGE SUNDAY WILL BECOME FORTIFIED BY A TIGHTENING
PRESSURE GRADIENT BETWEEN HIGH PRESSURE ACROSS THE NORTHEAST U.S.
AND A DEVELOPING TROPICAL LOW ACROSS THE BAHAMAS. THIS WILL SERVE TO
NOT ONLY PROLONG THE NE FLOW...BUT TO INCREASE ITS MAGNITUDE.
THUS...A SMALL CRAFT ADVISORY HAS BEEN ISSUED BEGINNING SUNDAY
MORNING. WINDS WILL COMMONLY BE SUSTAINED AT 20 TO 25 KT. A NE FETCH
WILL BUILD SEAS TO 4 TO 7 FT AND 8 FT OR HIGHER BEYOND 20 NM.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...THE MARINE COMMUNITY CAN EXPECT A
NORTHEAST FLOW TUESDAY ON THE ORDER OF 15-20 KNOTS. THIS FLOW WILL
DIMINISH QUITE A BIT WEDNESDAY ESSENTIALLY BECOMING VARIABLE BY
DAYS END. FOR THURSDAY A VERY LIGHT FLOW CAN BE EXPECTED AS THE
WATERS ARE IN BETWEEN RETREATING HIGH PRESSURE TO THE NORTH AND
THE BUILDING BERMUDA RIDGE. WILL LIKELY SEE WINDS MORE INFLUENCED
BY THE SEA BREEZE THIS DAY. SIGNIFICANT SEAS CONTINUE TO BE
PROBLEMATIC DEPENDING ON THE TRACK AND INTENSITY OF AL96. FORECAST
SHOWS 2-6 FEET TUESDAY WITH AN INCREASE MOSTLY IN THE OUTER WATERS
WEDNESDAY AND THURSDAY DUE ALMOST EXCLUSIVELY TO INCREASED SWELL
COMPONENT FROM THE AFOREMENTIONED SYSTEM.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM SUNDAY TO 8 PM EDT MONDAY FOR
AMZ250-252-254-256.
&&
$$
NEAR TERM...JDW
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...JDW/MRR
AREA FORECAST DISCUSSION
NWS RALEIGH NC
305 PM EDT SAT AUG 23 2014
.SYNOPSIS...A COLD FRONT WILL MOVE SOUTH ACROSS SOUTHERN VIRGINIA
AND NORTH CAROLINA THIS AFTERNOON AND TONIGHT. HIGH PRESSURE WILL
BUILD SOUTH INTO THE REGION WITH COOLER AND DRIER CONDITIONS EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 PM SATURDAY...
LATEST SURFACE ANALYSIS CONTINUES TO REVEAL A COMPLEX SURFACE
PATTERN WITH THE BACK DOOR COLD FRONT NOW EXTENDING FROM WESTERN
VIRGINIA EAST NEAR THE VA/NC BORDER AND THEN SOUTHEAST TOWARD THE
MID CAROLINA COAST. A SURFACE TROUGH ALSO EXTENDS NORTH TO
SOUTHEAST ACROSS THE NC/SC COASTAL REGION SEPARATING AN
INCREASINGLY DEEP EASTERLY FLOW AS NOTED BY THE HMT-SEPS WIND
PROFILER NEAR NEW BERN. A WEAK SURFACE LOW WAS ALSO ANALYZED JUST
NORTH OF KCHS WITH A STEAMY 903/79 OBSERVED AT KGGE. A NORTHWEST
FLOW ALOFT DOMINATES THE SYNOPTIC PATTERN WITH SEVERAL WAVES NOTED
IN THE FLOW ALONG WITH A STRENGTHENING NORTHERN STREAM JET POISED TO
DROP INTO THE MID ATLANTIC...NOTE THE 105KT JET AT 200 HPA AT KIAD
THIS MORNING. MORNING RAOBS ACROSS THE CAROLINAS DEPICT A VERY MOIST
ATMOSPHERE PRECIPITABLE WATER VALUES OF 120-135% OF NORMAL AT
KGSO/KMHX RESPECTIVELY.
NOT SURPRISED TO SHEE SHOWERS AND THUNDERSTORMS SLOWLY EXPANDING
THIS AFTERNOON GIVEN THE ENHANCED FLOW ALOFT...AT LEAST ONE
DISTURBANCE ALOFT OVER WESTERN VA AND MULTIPLE MECHANISMS FOR LOW
LEVEL CONVERGENCE. CURRENT RADAR TRENDS DEPICT ONE AREA OF
CONVECTION ACROSS THE NORTHERN PIEDMONT OF NC AND SOUTHERN VA IN
PROXIMITY TO THE SURFACE FRONT AND A DISTURBANCE IN THE NW FLOW
ALOFT. OTHER CONVECTION ACROSS THE COASTAL PLAIN AND COASTAL REGION
IS DRIVEN IN A MORE UNSTABLE AIR MASS NEAR THE SURFACE TROUGH. USED
A BLEND OF HRRR AND RAP HOURLY PRECIP FIELDS TO GENERATE THE HOURLY
POP/QPF/WX GRIDS FOR THIS AFTERNOON AND EVENING. WHILE CONVECTIVE
COVERAGE IS EXPECTED TO BE SOMEWHAT GENEROUS...MLCAPE VALUES WILL
GENERALLY RANGE LESS THAN 1000 J/KG EXCEPT ACROSS THE SOUTHERN
COASTAL PLAIN AND SANDHILLS WHERE VALUES MAY EXCEED 1500 J/KG WHICH
SHOULD MINIMIZE CONVECTIVE INTENSITY IN MOST LOCATIONS. THE BEST
FLOW ALOFT SHOULD REMAIN IN THE VA/MD/DE REGION WITH BULK SHEAR
VALUES IN OUR CWA CLIMBING TO AROUND 25KTS. THE BIGGER THREAT WILL
LIKELY BE ASSOCIATED WITH LOCALLY HEAVY RAIN WITH CELLS ORIENTED IN
THE NW FLOW THAT REPEATEDLY MOVE OVER A GIVEN AREA.
THE CONVECTIVE CONVERGE WILL INCREASE A BIT DURING THE NEXT SEVERAL
HOURS WITH THE FOCUS GRADUALLY SHIFTING SOUTH INTO THE EVENING
ALTHOUGH ISOLATED SHOWERS OR THUNDERSTORMS ARE POSSIBLE AT ANY TIME.
A PROMINENT AREA OF CONVECTION UPSTREAM ACROSS IL/IN IS PROGGED TO
WEAKEN AS IT MOVES SOUTHEAST AND SHOULD NOT IMPACT CENTRAL NC. LOW
TEMPERATURES TONIGHT WILL RANGE FROM THE UPPER 60S NORTHEAST TO
LOWER 70S SOUTHWEST. -BLAES
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT /...
AS OF 305 PM SATURDAY...
THE COLD FRONT WILL HAVE PUSHED WELL SOUTH OF THE REGION BY SUNDAY
MORNING WITH COOL HIGH PRESSURE BUILDING INTO CENTRAL NC IN ITS
WAKE. WHILE MUCH DRIER AIR WILL MOVE INTO THE REGION AT MID AND
UPPER LEVELS...SHALLOW LOW LEVEL MOISTURE WILL LINGER ESPECIALLY IN
AN ARC FROM THE WESTERN PIEDMONT INTO THE SOUTHERN PIEDMONT AND EAST
TOWARD THE SANDHILLS AND COASTAL PLAIN. A FEW SHOWERS MAY DEVELOP IN
THIS REGION...ESPECIALLY EARLY ON SUNDAY...BUT LIMITED MOISTURE AND
A CAPPING INVERSION SHOULD PRECLUDE DEEP CONVECTION AND LIMIT
PRECIPITATION COVERAGE. A FAIR AMOUNT OF STRATO CUMULUS IS EXPECTED
THOUGH. WITH A COOLER AIR MASS AND BELOW NORMAL THICKNESS VALUES...
HIGHS ON SUNDAY WILL ONLY RANGE IN THE LOWER TO MID 80S. LOWS SUNDAY
NIGHT WILL RANGE IN THE LOWER 60S. -BLAES
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 250 PM SATURDAY...
FOR MONDAY THROUGH MID-WEDNESDAY...LOOK FOR FAIR WEATHER WITH NEAR-
TO SLIGHTLY-BELOW NORMAL TEMPS (HIGHS IN THE LOW-MID 80S AND LOWS IN
THE LOW 60S) AS HIGH PRESSURE BUILDS IN TO THE CAROLINAS FROM THE
NORTH EARLY IN THE WEEK AND REMAINS OVER OUR AREA THROUGH MID-WEEK.
FORECAST SOUNDINGS SUGGEST PWAT WILL RANGE FROM 0.5-1.0 INCHES
DURING THIS TIME...WHICH IS WELL BELOW THE 1.35 INCH NORM FOR LATE
AUGUST.
A LARGE DEGREE OF UNCERTAINTY EXISTS FOR THE SECOND HALF OF THE
WEEK...AS THIS PART OF THE FORECAST IS LARGELY DEPENDENT ON WHAT
HAPPENS WITH INVEST 96L. TRACK MODELS HAVE BEEN QUITE SCATTERED AND
LITTLE AGREEMENT AMONG THE GEFS/NAEFS MEMBERS. HOWEVER...ITS WORTH
NOTING THAT THE TREND IN THE OPERATIONAL GFS HAS BEEN DEVELOPMENT
AND SLOW NORTHWARD MOVEMENT E OF FL DURING THE FIRST HALF OF THE
WEEK...THEN MOVING NNE ALONG BUT REMAINING OFF THE CAROLINA COAST
LATE IN THE WEEK. THE LATEST ECMWF IS SIMILAR WITH THE EVOLUTION OF
THIS SYSTEM...BUT IS FASTER AND ITS TRACK REMAINS FURTHER OFF THE
COAST...SHOWING THE LOW MOVING NE AWAY FROM THE EAST COAST ON
THURSDAY. ESSENTIALLY BOTH OF THESE SOLUTIONS WOULD KEEP CENTRAL NC
FAR ENOUGH WEST OF THE SYSTEM SUCH THAT OUR AREA WOULD REMAIN IN
FAIR WEATHER DURING THE SECOND HALF OF THE WEEK. TAKING THAT SYSTEM
OUT OF THE PICTURE...OUR NEXT CHANCE FOR WET WEATHER WOULD COME
DURING THE WEEKEND ASSOCIATED WITH EITHER THE NEXT TROUGH IN THE
WESTERLIES (PER GFS) OR INCREASING MOISTURE IN THE RETURN FLOW
AROUND THE RIDGE (PER THE ECWMF). IN SUMMARY...LOTS OF UNCERTAINTY
FOR THE SECOND HALF OF THE LONG TERM...SO WILL STICK CLOSE TO CLIMO
FOR TEMPS AND PERHAPS A LITTLE LOWER THAN CLIMO FOR POPS DURING THIS
TIME.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
AS OF 225 PM SATURDAY...
AS OF 18Z...SOME MVFR CONDITIONS MAINLY ASSOCIATED WITH CIGS PERSIST
ACROSS PARTS OF THE NORTHEAST PIEDMONT AND COASTAL PLAIN. ELSEWHERE
VFR CONDITIONS WITH MULTIPLE LOW TO MID CLOUD LAYERS ARE OBSERVED.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BECOME MORE NUMEROUS AND
MOVE SOUTHEAST THIS AFTERNOON AND EVENING ACROSS CENTRAL NC AS A
COLD FRONT AND AN UPPER LEVEL DISTURBANCE TRIGGERS AND THEN MAINTAIN
SCATTERED CONVECTION. INITIALLY THE PRECIPITATION WILL BE MOST
WIDESPREAD THIS AFTERNOON ACROSS THE COASTAL PLAIN...MAINLY EAST OF
THE KRWI AND KFAY TERMINALS. ANOTHER AREA OF SHOWERS AND
THUNDERSTORMS WILL ROTATE AND PUSH SOUTH ACROSS THE NORTHERN
PIEDMONT THIS AFTERNOON AND THEN GRADUALLY SHIFT SOUTH LATER THIS
AFTERNOON AND ESPECIALLY THIS EVENING. THE CONVECTION WILL TEND TO
SHIFT SOUTH...WEAKEN AND DECREASE IN COVERAGE LATER THIS EVENING AND
OVERNIGHT. EXPECT LOCAL REDUCTIONS TO MVR AND INTERMITTENTLY IFR
CONDITIONS IN SHOWERS AND THUNDERSTORMS. PREVAILING CEILINGS WILL
ALSO DECREASE OVERNIGHT AS COOLER AIR MOVES INTO THE REGION WITH
PERIODS OF IFR CONDITIONS IN LOW CLOUDS AND SOME FOG LIKELY TOWARD
DAYBREAK WITH HEATING AND AN INFLUX OF DRIER AIR FROM THE
NORTHEAST...CEILINGS SHOULD LIFT A COUPLE OF HOURS AFTER DAYBREAK
WITH VFR CONDITIONS PREVAILING BY LATE OR EARLY AFTERNOON.
LOOKING FURTHER AHEAD...HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
EXTEND INTO THE REGION FOR THE LATE SUNDAY THROUGH WEDNESDAY PERIOD
BRINGING A PERIOD OF GENERALLY FAIR WEATHER. EXCEPTIONS WOULD
INCLUDE THE POTENTIAL FOR SOME DAYBREAK FOG ON MONDAY AND TUESDAY
MORNINGS...ESPECIALLY ACROSS THE COASTAL PLAIN AND PERHAPS A
SHOWER ACROSS THE EASTERN SECTIONS IN A PERSISTENT NORTHEAST FLOW.
-BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...BLAES
LONG TERM...NP
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 PM EDT SAT AUG 23 2014
.SYNOPSIS...A COLD FRONT WILL MOVE SOUTH ACROSS SOUTHERN VIRGINIA
AND NORTH CAROLINA THIS AFTERNOON AND TONIGHT. HIGH PRESSURE WILL
BUILD SOUTH INTO THE REGION WITH COOLER AND DRIER CONDITIONS EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 PM SATURDAY...
LATEST SURFACE ANALYSIS CONTINUES TO REVEAL A COMPLEX SURFACE
PATTERN WITH THE BACK DOOR COLD FRONT NOW EXTENDING FROM WESTERN
VIRGINIA EAST NEAR THE VA/NC BORDER AND THEN SOUTHEAST TOWARD THE
MID CAROLINA COAST. A SURFACE TROUGH ALSO EXTENDS NORTH TO
SOUTHEAST ACROSS THE NC/SC COASTAL REGION SEPARATING AN
INCREASINGLY DEEP EASTERLY FLOW AS NOTED BY THE HMT-SEPS WIND
PROFILER NEAR NEW BERN. A WEAK SURFACE LOW WAS ALSO ANLAYZED JUST
NORTH OF KCHS WITH A STEAMY 903/79 OBSERVED AT KGGE. A NORTHWEST
FLOW ALOFT DOMINATES THE SYNOPTIC PATTERN WITH SEVERAL WAVES NOTED
IN THE FLOW ALONG WITH A STRENGTHENING NORTHERN STREAM JET POISED TO
DROP INTO THE MID ATLANTIC...NOTE THE 105KT JET AT 200 HPA AT KIAD
THIS MORNING. MORNING RAOBS ACROSS THE CAROLINAS DEPICT A VERY MOIST
ATMOSPHERE PRECIPITABLE WATER VALUES OF 120-135% OF NORMAL AT
KGSO/KMHX RESPECTIVELY.
NOT SURPRISED TO SHEE SHOWERS AND THUNDERSTORMS SLOWLY EXPANDING
THIS AFTERNOON GIVEN THE ENHANCED FLOW ALOFT...AT LEAST ONE
DISTURBANCE ALOFT OVER WESTERN VA AND MULTIPLE MECHANISMS FOR LOW
LEVEL CONVERGENCE. CURRENT RADAR TRENDS DEPICT ONE AREA OF
CONVECTION ACROSS THE NORTHERN PIEDMONT OF NC AND SOUTHERN VA IN
PROXIMITY TO THE SURFACE FRONT AND A DISTURBANCE IN THE NW FLOW
ALOFT. OTHER CONVECTION ACROSS THE COASTAL PLAIN AND COASTAL REGION
IS DRIVEN IN A MORE UNSTABLE AIR MASS NEAR THE SURFACE TROUGH. USED
A BLEND OF HRRR AND RAP HOURLY PRECIP FIELDS TO GENERATE THE HOURLY
POP/QPF/WX GRIDS FOR THIS AFTERNOON AND EVENING. WHILE CONVECTIVE
COVERAGE IS EXPECTED TO BE SOMEWHAT GENEROUS...MLCAPE VALUES WILL
GENERALLY RANGE LESS THAN 1000 J/KG EXCEPT ACROSS THE SOUTHERN
COASTAL PLAIN AND SANDHILLS WHERE VALUES MAY EXCEED 1500 J/KG WHICH
SHOULD MINIMIZE CONVECTIVE INTENSITY IN MOST LOCATIONS. THE BEST
FLOW ALOFT SHOULD REMAIN IN THE VA/MD/DE REGION WITH BULK SHEAR
VALUES IN OUR CWA CLIMBING TO AROUND 25KTS. THE BIGGER THREAT WILL
LIKELY BE ASSOCIATED WITH LOCALLY HEAVY RAIN WITH CELLS ORIENTED IN
THE NW FLOW THAT REPEATEDLY MOVE OVER A GIVEN AREA.
THE CONVECTIVE CONVERGE WILL INCREASE A BIT DURING THE NEXT SEVERAL
HOURS WITH THE FOCUS GRADUALLY SHIFTING SOUTH INTO THE EVENING
ALTHOUGH ISOLATED SHOWERS OR THUNDERSTORMS ARE POSSIBLE AT ANY TIME.
A PROMINENT AREA OF CONVECTION UPSTREAM ACROSS IL/IN IS PROGGED TO
WEAKEN AS IT MOVES SOUTHEAST AND SHOULD NOT IMPACT CENTRAL NC. LOW
TEMPERATURES TONIGHT WILL RANGE FROM THE UPPER 60S NORTHEAST TO
LOWER 70S SOUTHWEST. -BLAES
&&
.SHORT TERM /SUNDAY AND SUNDAY NIGHT /...
AS OF 306 AM SATURDAY...
SURFACE DRY AIR RIDGE EXTENDS SOUTHWARD INTO NC FROM A PARENT HIGH
POSITIONED OVER NORTHERN MID ATLANTIC. THIS SURFACE RIDGE SUPPORTED
ALOFT BY A BUILDING UPPER LEVEL RIDGE...STRETCHING FROM THE MID-
LOWER MS VALLEY NEWD INTO NEW ENGLAND. NELY LOW LEVEL FLOW WILL
ADVECT COOLER DRIER AIR INTO CENTRAL NC. THIS DRIER AIR WILL AID TO
DIMINISH ANY RESIDUAL STRATOCU.
LOW LEVEL THICKNESSES DROP TO VALUES 15-20M BELOW NORMAL FOR LATE
AUGUST. THIS YIELDS MAX TEMPS OF NEAR 80 ACROSS THE FAR NORTH-NW TO
LOW/MID 80S FAR SOUTH. MIN TEMPS SUNDAY NIGHT LOW-MD 60S.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 250 PM SATURDAY...
FOR MONDAY THROUGH MID-WEDNESDAY...LOOK FOR FAIR WEATHER WITH NEAR-
TO SLIGHTLY-BELOW NORMAL TEMPS (HIGHS IN THE LOW-MID 80S AND LOWS IN
THE LOW 60S) AS HIGH PRESSURE BUILDS IN TO THE CAROLINAS FROM THE
NORTH EARLY IN THE WEEK AND REMAINS OVER OUR AREA THROUGH MID-WEEK.
FORECAST SOUNDINGS SUGGEST PWAT WILL RANGE FROM 0.5-1.0 INCHES
DURING THIS TIME...WHICH IS WELL BELOW THE 1.35 INCH NORM FOR LATE
AUGUST.
A LARGE DEGREE OF UNCERTAINTY EXISTS FOR THE SECOND HALF OF THE
WEEK...AS THIS PART OF THE FORECAST IS LARGELY DEPENDENT ON WHAT
HAPPENS WITH INVEST 96L. TRACK MODELS HAVE BEEN QUITE SCATTERED AND
LITTLE AGREEMENT AMONG THE GEFS/NAEFS MEMBERS. HOWEVER...ITS WORTH
NOTING THAT THE TREND IN THE OPERATIONAL GFS HAS BEEN DEVELOPMENT
AND SLOW NORTHWARD MOVEMENT E OF FL DURING THE FIRST HALF OF THE
WEEK...THEN MOVING NNE ALONG BUT REMAINING OFF THE CAROLINA COAST
LATE IN THE WEEK. THE LATEST ECMWF IS SIMILAR WITH THE EVOLUTION OF
THIS SYSTEM...BUT IS FASTER AND ITS TRACK REMAINS FURTHER OFF THE
COAST...SHOWING THE LOW MOVING NE AWAY FROM THE EAST COAST ON
THURSDAY. ESSENTIALLY BOTH OF THESE SOLUTIONS WOULD KEEP CENTRAL NC
FAR ENOUGH WEST OF THE SYSTEM SUCH THAT OUR AREA WOULD REMAIN IN
FAIR WEATHER DURING THE SECOND HALF OF THE WEEK. TAKING THAT SYSTEM
OUT OF THE PICTURE...OUR NEXT CHANCE FOR WET WEATHER WOULD COME
DURING THE WEEKEND ASSOCIATED WITH EITHER THE NEXT TROUGH IN THE
WESTERLIES (PER GFS) OR INCREASING MOISTURE IN THE RETURN FLOW
AROUND THE RIDGE (PER THE ECWMF). IN SUMMARY...LOTS OF UNCERTAINTY
FOR THE SECOND HALF OF THE LONG TERM...SO WILL STICK CLOSE TO CLIMO
FOR TEMPS AND PERHAPS A LITTLE LOWER THAN CLIMO FOR POPS DURING THIS
TIME.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
AS OF 225 PM SATURDAY...
AS OF 18Z...SOME MVFR CONDITIONS MAINLY ASSOCIATED WITH CIGS PERSIST
ACROSS PARTS OF THE NORTHEAST PIEDMONT AND COASTAL PLAIN. ELSEWHERE
VFR CONDITIONS WITH MULTIPLE LOW TO MID CLOUD LAYERS ARE OBSERVED.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BECOME MORE NUMEROUS AND
MOVE SOUTHEAST THIS AFTERNOON AND EVENING ACROSS CENTRAL NC AS A
COLD FRONT AND AN UPPER LEVEL DISTURBANCE TRIGGERS AND THEN MAINTAIN
SCATTERED CONVECTION. INITIALLY THE PRECIPITATION WILL BE MOST
WIDESPREAD THIS AFTERNOON ACROSS THE COASTAL PLAIN...MAINLY EAST OF
THE KRWI AND KFAY TERMINALS. ANOTHER AREA OF SHOWERS AND
THUNDERSTORMS WILL ROTATE AND PUSH SOUTH ACROSS THE NORTHERN
PIEDMONT THIS AFTERNOON AND THEN GRADUALLY SHIFT SOUTH LATER THIS
AFTERNOON AND ESPECIALLY THIS EVENING. THE CONVECTION WILL TEND TO
SHIFT SOUTH...WEAKEN AND DECREASE IN COVERAGE LATER THIS EVENING AND
OVERNIGHT. EXPECT LOCAL REDUCTIONS TO MVR AND INTERMITTENTLY IFR
CONDITIONS IN SHOWERS AND THUNDERSTORMS. PREVAILING CEILINGS WILL
ALSO DECREASE OVERNIGHT AS COOLER AIR MOVES INTO THE REGION WITH
PERIODS OF IFR CONDITIONS IN LOW CLOUDS AND SOME FOG LIKELY TOWARD
DAYBREAK WITH HEATING AND AN INFLUX OF DRIER AIR FROM THE
NORTHEAST...CEILINGS SHOULD LIFT A COUPLE OF HOURS AFTER DAYBREAK
WITH VFR CONDITIONS PREVAILING BY LATE OR EARLY AFTERNOON.
LOOKING FURTHER AHEAD...HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
EXTEND INTO THE REGION FOR THE LATE SUNDAY THROUGH WEDNESDAY PERIOD
BRINGING A PERIOD OF GENERALLY FAIR WEATHER. EXCEPTIONS WOULD
INCLUDE THE POTENTIAL FOR SOME DAYBREAK FOG ON MONDAY AND TUESDAY
MORNINGS...ESPECIALLY ACROSS THE COASTAL PLAIN AND PERHAPS A
SHOWER ACROSS THE EASTERN SECTIONS IN A PERSISTENT NORTHEAST FLOW.
-BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES
SHORT TERM...WSS
LONG TERM...NP
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
250 PM EDT SAT AUG 23 2014
.SYNOPSIS...A COLD FRONT WILL MOVE SOUTH ACROSS SOUTHERN VIRGINIA
AND NORTH CAROLINA THIS AFTERNOON AND TONIGHT. HIGH PRESSURE WILL
BUILD SOUTH INTO THE REGION WITH COOLER AND DRIER CONDITIONS EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 1100 AM SATURDAY...
LATEST SURFACE ANALYSIS REVEALS A COMPLEX PATTERN WITH THE BACK
DOOR COLD FRONT NOW EXTENDING ACROSS NORTHEAST NC INTO SOUTHWESTERN
VA AS WELL AS A SURFACE TROUGH EXTENDING ALONG THE NC/SC COAST WITH
A WEAK SURFACE LOW CENTERED NEAR KILM. THE MAIN SURGE OF
COLDER/DRIER AIR LAGS BEHIND THE FRONT AND IS LOCATED ACROSS EASTERN
PA AND THE NORTHERN CHESAPEAKE BAY. A NORTHWEST FLOW DOMINATES THE
MID AND UPPER AIR PATTERN ACROSS THE CAROLINAS WITH A STRENGTHENING
NORTHERN STREAM JET POISED TO DROP INTO THE MID ATLANTIC THIS
AFTERNOON...NOTE THE 105KT JET AT 200 HPA AT KIAD THIS MORNING. THE
AIRMASS ACROSS THE REGION IS RATHER MOIST WITH PW VALUES OF 120-135%
OF NORMAL AT KGSO/KMHX RESPECTIVELY.
WITH THE ENHANCED FLOW ALOFT AND MULTIPLE MECHANISMS FOR LOCAL
CONVERGENCE...NOT SURPRISED THAT HIGH RESOLUTION GUIDANCE SUGGESTS
FAIRLY DECENT CONVECTIVE COVERAGE FOR THIS AFTERNOON. SHOWERS HAVE
ALREADY BEGUN TO BLOSSOM IN SOUTHERN VA IN PROXIMITY TO THE SURFACE
FRONT AND A DISTURBANCE IN THE NW FLOW ALOFT. OTHER CONVECTION IS
BUBBLING UP IN THE COASTAL PLAIN AND COASTAL REGION NEAR THE SURFACE
TROUGH. USED A BLEND OF HRRR AND RAP HOURLY PRECIP FIELDS TO
GENERATE THE HOURLY POP/QPF/WX GRIDS THIS AFTERNOON. WHILE
CONVECTIVE COVERAGE IS EXPECTED TO BE SOMEWHAT GENEROUS...ONLY A
WEAKLY UNSTABLE AIRMASS WITH MLCAPE VALUES LESS THAN 1000 SHOULD
MINIMIZE OVERAL INTENSITY. THE BEST FLOW ALOFT SHOULD REMAIN IN THE
VA/MD/DE REGION WITH BULK SHEAR VALUES IN OUR CWA CLIMBING TO AROUND
2 5KTS. THE BIGGER THREAT WILL LIKELY BE ASSOCIATED WITH LOCALLY
HEAVY RAIN WITH CELLS ORIENTED IN THE NW FLOW THAT REPEATEDLY MOVE
OVER A GIVEN AREA. CLOUD COVER AND SCT CONVECTION SHOULD HOLD
TEMPERATURES DOWN A BIT...ESPECIALLY IN THE NORTHEAST. A LITTLE BIT
MORE SUNSHINE ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS SHOULD
ALLOW TEMPERATURES TO WARM TO AROUND OR JUST ABOVE 90. -BLAES
MAIN AREA OF CONVECTION IS FORECAST TO BEGIN PUSHING TO THE SOUTH OF
THE AREA BY THIS EVENING... WHILE THE LOW LEVEL FRONTAL ZONE BEGINS
TO MOVE INTO THE AREA. THIS SHOULD YIELD A CONTINUED LOW END CHANCE
OF AT LEAST SOME SHOWERS THOUGH. WITH A LOW LEVEL EAST TO
NORTHEASTERLY FLOW TONIGHT... LOW STRATUS IS APT TO DEVELOP... WITH
PATCHY LIGHT DRIZZLE EVEN. THE MAIN PUSH OF THE COOLER AIR SHOULD
HOLD OFF UNTIL AFTER DAYBREAK SUNDAY. THUS... EXPECT LOW TEMPS WILL
BE IN THE UPPER 60S TO LOWER 70S.
SUNDAY: SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA
ON SUNDAY... ALONG WITH DRIER AIR ALOFT. THIS WILL YIELD MUCH DRIER
CONDITIONS ON SUNDAY... WITH SKIES BECOMING PARTLY SUNNY BY
AFTERNOON. HIGH TEMPS WILL BE COOLER... AROUND 80 NORTHEAST TO MID
80S SOUTH/SOUTHWEST. CAN`T RULE OUT SOME LIGHT SHOWERS IN THE EAST
TO EAST-NORTHEASTERLY LOW LEVEL FLOW IN THE MORNING TO EARLY
AFTERNOON THOUGH.
&&
.SHORT TERM /SUNDAY NIGHT AND MONDAY/...
AS OF 306 AM SATURDAY...
SURFACE DRY AIR RIDGE EXTENDS SOUTHWARD INTO NC FROM A PARENT HIGH
POSITIONED OVER NORTHERN MID ATLANTIC. THIS SURFACE RIDGE SUPPORTED
ALOFT BY A BUILDING UPPER LEVEL RIDGE...STRETCHING FROM THE MID-
LOWER MS VALLEY NEWD INTO NEW ENGLAND. NELY LOW LEVEL FLOW WILL
ADVECT COOLER DRIER AIR INTO CENTRAL NC. THIS DRIER AIR WILL AID TO
DIMINISH ANY RESIDUAL STRATOCU.
LOW LEVEL THICKNESSES DROP TO VALUES 15-20M BELOW NORMAL FOR LATE
AUGUST. THIS YIELDS MAX TEMPS OF NEAR 80 ACROSS THE FAR NORTH-NW TO
LOW/MID 80S FAR SOUTH. MIN TEMPS SUNDAY NIGHT LOW-MD 60S.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
AS OF 250 PM SATURDAY...
FOR MONDAY THROUGH MID-WEDNESDAY...LOOK FOR FAIR WEATHER WITH NEAR-
TO SLIGHTLY-BELOW NORMAL TEMPS (HIGHS IN THE LOW-MID 80S AND LOWS IN
THE LOW 60S) AS HIGH PRESSURE BUILDS IN TO THE CAROLINAS FROM THE
NORTH EARLY IN THE WEEK AND REMAINS OVER OUR AREA THROUGH MID-WEEK.
FORECAST SOUNDINGS SUGGEST PWAT WILL RANGE FROM 0.5-1.0 INCHES
DURING THIS TIME...WHICH IS WELL BELOW THE 1.35 INCH NORM FOR LATE
AUGUST.
A LARGE DEGREE OF UNCERTAINTY EXISTS FOR THE SECOND HALF OF THE
WEEK...AS THIS PART OF THE FORECAST IS LARGELY DEPENDENT ON WHAT
HAPPENS WITH INVEST 96L. TRACK MODELS HAVE BEEN QUITE SCATTERED AND
LITTLE AGREEMENT AMONG THE GEFS/NAEFS MEMBERS. HOWEVER...ITS WORTH
NOTING THAT THE TREND IN THE OPERATIONAL GFS HAS BEEN DEVELOPMENT
AND SLOW NORTHWARD MOVEMENT E OF FL DURING THE FIRST HALF OF THE
WEEK...THEN MOVING NNE ALONG BUT REMAINING OFF THE CAROLINA COAST
LATE IN THE WEEK. THE LATEST ECMWF IS SIMILAR WITH THE EVOLUTION OF
THIS SYSTEM...BUT IS FASTER AND ITS TRACK REMAINS FURTHER OFF THE
COAST...SHOWING THE LOW MOVING NE AWAY FROM THE EAST COAST ON
THURSDAY. ESSENTIALLY BOTH OF THESE SOLUTIONS WOULD KEEP CENTRAL NC
FAR ENOUGH WEST OF THE SYSTEM SUCH THAT OUR AREA WOULD REMAIN IN
FAIR WEATHER DURING THE SECOND HALF OF THE WEEK. TAKING THAT SYSTEM
OUT OF THE PICTURE...OUR NEXT CHANCE FOR WET WEATHER WOULD COME
DURING THE WEEKEND ASSOCIATED WITH EITHER THE NEXT TROUGH IN THE
WESTERLIES (PER GFS) OR INCREASING MOISTURE IN THE RETURN FLOW
AROUND THE RIDGE (PER THE ECWMF). IN SUMMARY...LOTS OF UNCERTAINTY
FOR THE SECOND HALF OF THE LONG TERM...SO WILL STICK CLOSE TO CLIMO
FOR TEMPS AND PERHAPS A LITTLE LOWER THAN CLIMO FOR POPS DURING THIS
TIME.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
AS OF 225 PM SATURDAY...
AS OF 18Z...SOME MVFR CONDITIONS MAINLY ASSOCIATED WITH CIGS PERSIST
ACROSS PARTS OF THE NORTHEAST PIEDMONT AND COASTAL PLAIN. ELSEWHERE
VFR CONDITIONS WITH MULTIPLE LOW TO MID CLOUD LAYERS ARE OBSERVED.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BECOME MORE NUMEROUS AND
MOVE SOUTHEAST THIS AFTERNOON AND EVENING ACROSS CENTRAL NC AS A
COLD FRONT AND AN UPPER LEVEL DISTURBANCE TRIGGERS AND THEN MAINTAIN
SCATTERED CONVECTION. INITIALLY THE PRECIPITATION WILL BE MOST
WIDESPREAD THIS AFTERNOON ACROSS THE COASTAL PLAIN...MAINLY EAST OF
THE KRWI AND KFAY TERMINALS. ANOTHER AREA OF SHOWERS AND
THUNDERSTORMS WILL ROTATE AND PUSH SOUTH ACROSS THE NORTHERN
PIEDMONT THIS AFTERNOON AND THEN GRADUALLY SHIFT SOUTH LATER THIS
AFTERNOON AND ESPECIALLY THIS EVENING. THE CONVECTION WILL TEND TO
SHIFT SOUTH...WEAKEN AND DECREASE IN COVERAGE LATER THIS EVENING AND
OVERNIGHT. EXPECT LOCAL REDUCTIONS TO MVR AND INTERMITTENTLY IFR
CONDITIONS IN SHOWERS AND THUNDERSTORMS. PREVAILING CEILINGS WILL
ALSO DECREASE OVERNIGHT AS COOLER AIR MOVES INTO THE REGION WITH
PERIODS OF IFR CONDITIONS IN LOW CLOUDS AND SOME FOG LIKELY TOWARD
DAYBREAK WITH HEATING AND AN INFLUX OF DRIER AIR FROM THE
NORTHEAST...CEILINGS SHOULD LIFT A COUPLE OF HOURS AFTER DAYBREAK
WITH VFR CONDITIONS PREVAILING BY LATE OR EARLY AFTERNOON.
LOOKING FURTHER AHEAD...HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
EXTEND INTO THE REGION FOR THE LATE SUNDAY THROUGH WEDNESDAY PERIOD
BRINGING A PERIOD OF GENERALLY FAIR WEATHER. EXCEPTIONS WOULD
INCLUDE THE POTENTIAL FOR SOME DAYBREAK FOG ON MONDAY AND TUESDAY
MORNINGS...ESPECIALLY ACROSS THE COASTAL PLAIN AND PERHAPS A
SHOWER ACROSS THE EASTERN SECTIONS IN A PERSISTENT NORTHEAST FLOW.
-BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES/BSD
SHORT TERM...WSS
LONG TERM...NP
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
225 PM EDT SAT AUG 23 2014
.SYNOPSIS...A COLD FRONT WILL MOVE SOUTH ACROSS SOUTHERN VIRGINIA
AND NORTH CAROLINA THIS AFTERNOON AND TONIGHT. HIGH PRESSURE WILL
BUILD SOUTH INTO THE REGION WITH COOLER AND DRIER CONDITIONS EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 1100 AM SATURDAY...
LATEST SURFACE ANALYSIS REVEALS A COMPLEX PATTERN WITH THE BACK
DOOR COLD FRONT NOW EXTENDING ACROSS NORTHEAST NC INTO SOUTHWESTERN
VA AS WELL AS A SURFACE TROUGH EXTENDING ALONG THE NC/SC COAST WITH
A WEAK SURFACE LOW CENTERED NEAR KILM. THE MAIN SURGE OF
COLDER/DRIER AIR LAGS BEHIND THE FRONT AND IS LOCATED ACROSS EASTERN
PA AND THE NORTHERN CHESAPEAKE BAY. A NORTHWEST FLOW DOMINATES THE
MID AND UPPER AIR PATTERN ACROSS THE CAROLINAS WITH A STRENGTHENING
NORTHERN STREAM JET POISED TO DROP INTO THE MID ATLANTIC THIS
AFTERNOON...NOTE THE 105KT JET AT 200 HPA AT KIAD THIS MORNING. THE
AIRMASS ACROSS THE REGION IS RATHER MOIST WITH PW VALUES OF 120-135%
OF NORMAL AT KGSO/KMHX RESPECTIVELY.
WITH THE ENHANCED FLOW ALOFT AND MULTIPLE MECHANISMS FOR LOCAL
CONVERGENCE...NOT SURPRISED THAT HIGH RESOLUTION GUIDANCE SUGGESTS
FAIRLY DECENT CONVECTIVE COVERAGE FOR THIS AFTERNOON. SHOWERS HAVE
ALREADY BEGUN TO BLOSSOM IN SOUTHERN VA IN PROXIMITY TO THE SURFACE
FRONT AND A DISTURBANCE IN THE NW FLOW ALOFT. OTHER CONVECTION IS
BUBBLING UP IN THE COASTAL PLAIN AND COASTAL REGION NEAR THE SURFACE
TROUGH. USED A BLEND OF HRRR AND RAP HOURLY PRECIP FIELDS TO
GENERATE THE HOURLY POP/QPF/WX GRIDS THIS AFTERNOON. WHILE
CONVECTIVE COVERAGE IS EXPECTED TO BE SOMEWHAT GENEROUS...ONLY A
WEAKLY UNSTABLE AIRMASS WITH MLCAPE VALUES LESS THAN 1000 SHOULD
MINIMIZE OVERAL INTENSITY. THE BEST FLOW ALOFT SHOULD REMAIN IN THE
VA/MD/DE REGION WITH BULK SHEAR VALUES IN OUR CWA CLIMBING TO AROUND
2 5KTS. THE BIGGER THREAT WILL LIKELY BE ASSOCIATED WITH LOCALLY
HEAVY RAIN WITH CELLS ORIENTED IN THE NW FLOW THAT REPEATEDLY MOVE
OVER A GIVEN AREA. CLOUD COVER AND SCT CONVECTION SHOULD HOLD
TEMPERATURES DOWN A BIT...ESPECIALLY IN THE NORTHEAST. A LITTLE BIT
MORE SUNSHINE ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS SHOULD
ALLOW TEMPERATURES TO WARM TO AROUND OR JUST ABOVE 90. -BLAES
MAIN AREA OF CONVECTION IS FORECAST TO BEGIN PUSHING TO THE SOUTH OF
THE AREA BY THIS EVENING... WHILE THE LOW LEVEL FRONTAL ZONE BEGINS
TO MOVE INTO THE AREA. THIS SHOULD YIELD A CONTINUED LOW END CHANCE
OF AT LEAST SOME SHOWERS THOUGH. WITH A LOW LEVEL EAST TO
NORTHEASTERLY FLOW TONIGHT... LOW STRATUS IS APT TO DEVELOP... WITH
PATCHY LIGHT DRIZZLE EVEN. THE MAIN PUSH OF THE COOLER AIR SHOULD
HOLD OFF UNTIL AFTER DAYBREAK SUNDAY. THUS... EXPECT LOW TEMPS WILL
BE IN THE UPPER 60S TO LOWER 70S.
SUNDAY: SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA
ON SUNDAY... ALONG WITH DRIER AIR ALOFT. THIS WILL YIELD MUCH DRIER
CONDITIONS ON SUNDAY... WITH SKIES BECOMING PARTLY SUNNY BY
AFTERNOON. HIGH TEMPS WILL BE COOLER... AROUND 80 NORTHEAST TO MID
80S SOUTH/SOUTHWEST. CAN`T RULE OUT SOME LIGHT SHOWERS IN THE EAST
TO EAST-NORTHEASTERLY LOW LEVEL FLOW IN THE MORNING TO EARLY
AFTERNOON THOUGH.
&&
.SHORT TERM /SUNDAY NIGHT AND MONDAY/...
AS OF 306 AM SATURDAY...
SURFACE DRY AIR RIDGE EXTENDS SOUTHWARD INTO NC FROM A PARENT HIGH
POSITIONED OVER NORTHERN MID ATLANTIC. THIS SURFACE RIDGE SUPPORTED
ALOFT BY A BUILDING UPPER LEVEL RIDGE...STRETCHING FROM THE MID-
LOWER MS VALLEY NEWD INTO NEW ENGLAND. NELY LOW LEVEL FLOW WILL
ADVECT COOLER DRIER AIR INTO CENTRAL NC. THIS DRIER AIR WILL AID TO
DIMINISH ANY RESIDUAL STRATOCU.
LOW LEVEL THICKNESSES DROP TO VALUES 15-20M BELOW NORMAL FOR LATE
AUGUST. THIS YIELDS MAX TEMPS OF NEAR 80 ACROSS THE FAR NORTH-NW TO
LOW/MID 80S FAR SOUTH. MIN TEMPS SUNDAY NIGHT LOW-MD 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 306 AM SATURDAY...
MONDAY NIGHT THROUGH THURSDAY...TRANQUIL WEATHER PATTERN WILL
CONTINUE. UPPER LEVEL RIDGE WILL REMAIN HIGHLY AMPLIFIED UNTIL LATE
WEDNESDAY INTO THURSDAY AT WHICH TIME A S/W IN THE NORTHERN STREAM
WILL BE EXITING THE NORTHERN PLAINS INTO THE GREAT LAKES. THE
APPROACH OF THIS SYSTEM WILL WEAKEN/SUPPRESS THE UPPER RIDGE
SOUTHWARD. ASSOCIATED SFC RIDGE WILL MAINTAIN A DRY WEATHER REGIME
WITH MODERATING TEMPERATURES THROUGH THURSDAY. MAX TEMPS TUESDAY
NEAR 80 NORTH TO LOWER 80S SOUTH WARM TO THE MID-UPPER 80S BY
THURSDAY. MIN TEMPS ALSO GRADUALLY MODIFY...FROM THE UPPER 50S-LOWER
60S TUESDAY MORNING TO THE MID 60S THURSDAY MORNING.
FORECAST CONFIDENCE WANES THURSDAY INTO FRIDAY AS GFS IS MUCH FASTER
WITH THE APPROACH OF THE NORTHERN STREAM S/W TOWARD THE EAST COAST
VERSUS THE SLOWER ECMWF. ALSO OF CONCERN IS THE EVENTUAL TRACK OF
THE TROPICAL SYSTEM THAT IS EXPECTED TO TRACK PARALLEL BUT OFFSHORE
OF THE SE U.S. COAST. LATEST MODEL GUIDANCE (MAINLY ECMWF) HAS
SHIFTED A LITTLE MORE TO THE WEST...WITH MAJOR TIMING DIFFERENCES
(ECMWF MUCH FASTER COMPARED TO THE GFS). WITH THE TROPICAL SYSTEM
OFFSHORE AND A TROUGH IN THE VICINITY OF THE GREAT LAKES/MID MS
VALLEY...WOULD EXPECT A NARROW RIDGE OVER THE CAROLINAS. UNTIL THE
DIFFERENCES ARE RESOLVED...FAVOR A WARM AND MAINLY DRY FORECAST FOR
THE END OF THE WORK WEEK. HAVE WARMED TEMPS INTO THE MID 80-AROUND
90 FOR MAX TEMPS FRIDAY WHILE DECREASED RAIN CHANCE TO SLIGHT CHANCE.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
AS OF 225 PM SATURDAY...
AS OF 18Z...SOME MVFR CONDITIONS MAINLY ASSOCIATED WITH CIGS PERSIST
ACROSS PARTS OF THE NORTHEAST PIEDMONT AND COASTAL PLAIN. ELSEWHERE
VFR CONDITIONS WITH MULTIPLE LOW TO MID CLOUD LAYERS ARE OBSERVED.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BECOME MORE NUMEROUS AND
MOVE SOUTHEAST THIS AFTERNOON AND EVENING ACROSS CENTRAL NC AS A
COLD FRONT AND AN UPPER LEVEL DISTURBANCE TRIGGERS AND THEN MAINTAIN
SCATTERED CONVECTION. INITIALLY THE PRECIPITATION WILL BE MOST
WIDESPREAD THIS AFTERNOON ACROSS THE COASTAL PLAIN...MAINLY EAST OF
THE KRWI AND KFAY TERMINALS. ANOTHER AREA OF SHOWERS AND
THUNDERSTORMS WILL ROTATE AND PUSH SOUTH ACROSS THE NORTHERN
PIEDMONT THIS AFTERNOON AND THEN GRADUALLY SHIFT SOUTH LATER THIS
AFTERNOON AND ESPECIALLY THIS EVENING. THE CONVECTION WILL TEND TO
SHIFT SOUTH...WEAKEN AND DECREASE IN COVERAGE LATER THIS EVENING AND
OVERNIGHT. EXPECT LOCAL REDUCTIONS TO MVR AND INTERMITTENTLY IFR
CONDITIONS IN SHOWERS AND THUNDERSTORMS. PREVAILING CEILINGS WILL
ALSO DECREASE OVERNIGHT AS COOLER AIR MOVES INTO THE REGION WITH
PERIODS OF IFR CONDITIONS IN LOW CLOUDS AND SOME FOG LIKELY TOWARD
DAYBREAK WITH HEATING AND AN INFLUX OF DRIER AIR FROM THE
NORTHEAST...CEILINGS SHOULD LIFT A COUPLE OF HOURS AFTER DAYBREAK
WITH VFR CONDITIONS PREVAILING BY LATE OR EARLY AFTERNOON.
LOOKING FURTHER AHEAD...HIGH PRESSURE AT THE SURFACE AND ALOFT WILL
EXTEND INTO THE REGION FOR THE LATE SUNDAY THROUGH WEDNESDAY PERIOD
BRINGING A PERIOD OF GENERALLY FAIR WEATHER. EXCEPTIONS WOULD
INCLUDE THE POTENTIAL FOR SOME DAYBREAK FOG ON MONDAY AND TUESDAY
MORNINGS...ESPECIALLY ACROSS THE COASTAL PLAIN AND PERHAPS A
SHOWER ACROSS THE EASTERN SECTIONS IN A PERSISTENT NORTHEAST FLOW.
-BLAES
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES/BSD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BLAES
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1100 AM EDT SAT AUG 23 2014
.SYNOPSIS...A COLD FRONT WILL MOVE SOUTH ACROSS SOUTHERN VIRGINIA
AND NORTH CAROLINA THIS AFTERNOON AND TONIGHT. HIGH PRESSURE WILL
BUILD SOUTH INTO THE REGION WITH COOLER AND DRIER CONDITIONS EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
AS OF 1100 AM SATURDAY...
LATEST SURFACE ANALYSIS REVEALS A COMPLEX PATTERN WITH THE BACK
DOOR COLD FRONT NOW EXTENDING ACROSS NORTHEAST NC INTO SOUTHWESTERN
VA AS WELL AS A SURFACE TROUGH EXTENDING ALONG THE NC/SC COAST WITH
A WEAK SURFACE LOW CENTERED NEAR KILM. THE MAIN SURGE OF
COLDER/DRIER AIR LAGS BEHIND THE FRONT AND IS LOCATED ACROSS EASTERN
PA AND THE NORTHERN CHESAPEAKE BAY. A NORTHWEST FLOW DOMINATES THE
MID AND UPPER AIR PATTERN ACROSS THE CAROLINAS WITH A STRENGTHENING
NORTHERN STREAM JET POISED TO DROP INTO THE MID ATLANTIC THIS
AFTERNOON...NOTE THE 105KT JET AT 200 HPA AT KIAD THIS MORNING. THE
AIRMASS ACROSS THE REGION IS RATHER MOIST WITH PW VALUES OF 120-135%
OF NORMAL AT KGSO/KMHX RESPECTIVELY.
WITH THE ENHANCED FLOW ALOFT AND MULTIPLE MECHANISMS FOR LOCAL
CONVERGENCE...NOT SURPRISED THAT HIGH RESOLUTION GUIDANCE SUGGESTS
FAIRLY DECENT CONVECTIVE COVERAGE FOR THIS AFTERNOON. SHOWERS HAVE
ALREADY BEGUN TO BLOSSOM IN SOUTHERN VA IN PROXIMITY TO THE SURFACE
FRONT AND A DISTURBANCE IN THE NW FLOW ALOFT. OTHER CONVECTION IS
BUBBLING UP IN THE COASTAL PLAIN AND COASTAL REGION NEAR THE SURFACE
TROUGH. USED A BLEND OF HRRR AND RAP HOURLY PRECIP FIELDS TO
GENERATE THE HOURLY POP/QPF/WX GRIDS THIS AFTERNOON. WHILE
CONVECTIVE COVERAGE IS EXPECTED TO BE SOMEWHAT GENEROUS...ONLY A
WEAKLY UNSTABLE AIRMASS WITH MLCAPE VALUES LESS THAN 1000 SHOULD
MINIMIZE OVERAL INTENSITY. THE BEST FLOW ALOFT SHOULD REMAIN IN THE
VA/MD/DE REGION WITH BULK SHEAR VALUES IN OUR CWA CLIMBING TO AROUND
2 5KTS. THE BIGGER THREAT WILL LIKELY BE ASSOCIATED WITH LOCALLY
HEAVY RAIN WITH CELLS ORIENTED IN THE NW FLOW THAT REPEATEDLY MOVE
OVER A GIVEN AREA. CLOUD COVER AND SCT CONVECTION SHOULD HOLD
TEMPERATURES DOWN A BIT...ESPECIALLY IN THE NORTHEAST. A LITTLE BIT
MORE SUNSHINE ACROSS THE SOUTHERN PIEDMONT AND SANDHILLS SHOULD
ALLOW TEMPERATURES TO WARM TO AROUND OR JUST ABOVE 90. -BLAES
MAIN AREA OF CONVECTION IS FORECAST TO BEGIN PUSHING TO THE SOUTH OF
THE AREA BY THIS EVENING... WHILE THE LOW LEVEL FRONTAL ZONE BEGINS
TO MOVE INTO THE AREA. THIS SHOULD YIELD A CONTINUED LOW END CHANCE
OF AT LEAST SOME SHOWERS THOUGH. WITH A LOW LEVEL EAST TO
NORTHEASTERLY FLOW TONIGHT... LOW STRATUS IS APT TO DEVELOP... WITH
PATCHY LIGHT DRIZZLE EVEN. THE MAIN PUSH OF THE COOLER AIR SHOULD
HOLD OFF UNTIL AFTER DAYBREAK SUNDAY. THUS... EXPECT LOW TEMPS WILL
BE IN THE UPPER 60S TO LOWER 70S.
SUNDAY: SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE AREA
ON SUNDAY... ALONG WITH DRIER AIR ALOFT. THIS WILL YIELD MUCH DRIER
CONDITIONS ON SUNDAY... WITH SKIES BECOMING PARTLY SUNNY BY
AFTERNOON. HIGH TEMPS WILL BE COOLER... AROUND 80 NORTHEAST TO MID
80S SOUTH/SOUTHWEST. CAN`T RULE OUT SOME LIGHT SHOWERS IN THE EAST
TO EAST-NORTHEASTERLY LOW LEVEL FLOW IN THE MORNING TO EARLY
AFTERNOON THOUGH.
&&
.SHORT TERM /SUNDAY NIGHT AND MONDAY/...
AS OF 306 AM SATURDAY...
SURFACE DRY AIR RIDGE EXTENDS SOUTHWARD INTO NC FROM A PARENT HIGH
POSITIONED OVER NORTHERN MID ATLANTIC. THIS SURFACE RIDGE SUPPORTED
ALOFT BY A BUILDING UPPER LEVEL RIDGE...STRETCHING FROM THE MID-
LOWER MS VALLEY NEWD INTO NEW ENGLAND. NELY LOW LEVEL FLOW WILL
ADVECT COOLER DRIER AIR INTO CENTRAL NC. THIS DRIER AIR WILL AID TO
DIMINISH ANY RESIDUAL STRATOCU.
LOW LEVEL THICKNESSES DROP TO VALUES 15-20M BELOW NORMAL FOR LATE
AUGUST. THIS YIELDS MAX TEMPS OF NEAR 80 ACROSS THE FAR NORTH-NW TO
LOW/MID 80S FAR SOUTH. MIN TEMPS SUNDAY NIGHT LOW-MD 60S.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 306 AM SATURDAY...
MONDAY NIGHT THROUGH THURSDAY...TRANQUIL WEATHER PATTERN WILL
CONTINUE. UPPER LEVEL RIDGE WILL REMAIN HIGHLY AMPLIFIED UNTIL LATE
WEDNESDAY INTO THURSDAY AT WHICH TIME A S/W IN THE NORTHERN STREAM
WILL BE EXITING THE NORTHERN PLAINS INTO THE GREAT LAKES. THE
APPROACH OF THIS SYSTEM WILL WEAKEN/SUPPRESS THE UPPER RIDGE
SOUTHWARD. ASSOCIATED SFC RIDGE WILL MAINTAIN A DRY WEATHER REGIME
WITH MODERATING TEMPERATURES THROUGH THURSDAY. MAX TEMPS TUESDAY
NEAR 80 NORTH TO LOWER 80S SOUTH WARM TO THE MID-UPPER 80S BY
THURSDAY. MIN TEMPS ALSO GRADUALLY MODIFY...FROM THE UPPER 50S-LOWER
60S TUESDAY MORNING TO THE MID 60S THURSDAY MORNING.
FORECAST CONFIDENCE WANES THURSDAY INTO FRIDAY AS GFS IS MUCH FASTER
WITH THE APPROACH OF THE NORTHERN STREAM S/W TOWARD THE EAST COAST
VERSUS THE SLOWER ECMWF. ALSO OF CONCERN IS THE EVENTUAL TRACK OF
THE TROPICAL SYSTEM THAT IS EXPECTED TO TRACK PARALLEL BUT OFFSHORE
OF THE SE U.S. COAST. LATEST MODEL GUIDANCE (MAINLY ECMWF) HAS
SHIFTED A LITTLE MORE TO THE WEST...WITH MAJOR TIMING DIFFERENCES
(ECMWF MUCH FASTER COMPARED TO THE GFS). WITH THE TROPICAL SYSTEM
OFFSHORE AND A TROUGH IN THE VICINITY OF THE GREAT LAKES/MID MS
VALLEY...WOULD EXPECT A NARROW RIDGE OVER THE CAROLINAS. UNTIL THE
DIFFERENCES ARE RESOLVED...FAVOR A WARM AND MAINLY DRY FORECAST FOR
THE END OF THE WORK WEEK. HAVE WARMED TEMPS INTO THE MID 80-AROUND
90 FOR MAX TEMPS FRIDAY WHILE DECREASED RAIN CHANCE TO SLIGHT CHANCE.
&&
.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
AS OF 655 AM SATURDAY...
A FEW LIGHT ISOLATED TO LOCALLY SCATTERED SHOWERS CONTINUE TO MOVE
ACROSS NORTHEAST PORTIONS OF CENTRAL NC THIS MORNING... POSSIBLY
AFFECTING KRDU AND KRWI FOR THE NEXT COUPLE OF HOURS. HOWEVER...
CONDITIONS ARE GENERALLY EXPECTED TO REMAIN VFR WITH THESE SHOWERS.
GREATER CONVECTIVE COVERAGE IS EXPECTED LATER THIS MORNING INTO THE
AFTERNOON AS A SERIES OF UPPER LEVEL DISTURBANCES TRACK S/SSE ACROSS
THE CAROLINAS AND A BACK DOOR COLD FRONT/PRE-FRONTAL TROUGH
PROGRESSES TOWARDS CENTRAL NC FROM THE N/NE. THUS... WILL MENTION A
TEMPO GROUP FOR SHOWERS AND SUB-VFR CONDITIONS IN THE TAFS FOR THE
AFTERNOON. THUNDERSTORMS WILL BE POSSIBLE AS WELL... BUT WILL HOLD
OFF ADDING THUNDER UNTIL WE HAVE A HIGHER CONFIDENCE THAT A GIVEN
LOCATION WILL BE AFFECTED BY A THUNDERSTORM. THE STRONGEST STORMS
WILL HAVE THE POTENTIAL TO PRODUCE IFR/LIFR VISBYS AND STRONG WIND
GUSTS.
IFR TO POSSIBLY EVEN LIFR CEILINGS WILL BE POSSIBLE IN THE WAKE OF
THE BACKDOOR COLD FRONT TONIGHT THROUGH MID-DAY SUNDAY...THOUGH
COVERAGE AND DURATION REMAIN A BIT UNCERTAIN (HIGHEST CONFIDENCES OF
SUB-VFR CONDITIONS AT KGSO/KINT). AN UPPER LEVEL RIDGE CENTERED IN
VICINITY OF THE SOUTHERN APPALACHIANS SHOULD RESULT IN BETTER-THAN-
NORMAL CHANCES FOR VFR CONDITIONS MON-WED...THOUGH A PERSISTENT E/NE
LOW-LEVEL FLOW MAY ALLOW ADEQUATE MOISTURE FOR LOW-TOPPED SHOWER
ACTIVITY...ESP AT THE EASTERN TERMINALS (FAY/RWI).
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BLAES
NEAR TERM...BLAES/BSD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BSD/VINCENT
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
146 AM EDT SAT AUG 23 2014
.SYNOPSIS...
A COLD FRONT WILL SLIP SOUTHWARD INTO THE AREA SATURDAY. THIS FRONT
WILL BRING A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS SATURDAY..
.BEFORE MUCH COOLER AND DRIER AIR FILTERS INTO THE REGION FOR
SUNDAY. HIGH PRESSURE EXPANDING SOUTH FROM NEW ENGLAND WILL BRING
COOL AND DRY WEATHER FOR THE FIRST HALF OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1:40 AM SATURDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSIONS FOLLOW:
ALTHOUGH IT AFFECTED ONLY A SMALL PORTION OF OUR FORECAST AREA
THIS EVENING`S STORMS WERE IMPRESSIVE. WIND GUSTS WERE MEASURED AS
HIGH AS 47 MPH AT WRIGHTSVILLE BEACH...42 MPH AT THE WILMINGTON
STATE PORT...AND 39 MPH AT THE WILMINGTON AIRPORT. DUAL-POL RADAR
PRECIP ESTIMATIONS APPEAR TO BE RUNNING WITHIN WITHIN 5-10% OF
ACTUAL GAUGE TOTALS WITH INDICATE 0.5 TO 2.5 INCH TOTALS ARE
WIDESPREAD ACROSS NEW HANOVER AND EASTERN BRUNSWICK COUNTIES.
NOW THAT THIS WAVE OF STORMS IS OFFSHORE...ATTENTION TURNS TO THE
NEXT UPPER DISTURBANCE CURRENTLY MOVING SOUTHEAST ACROSS THE NC/VA
BORDER. THE LAST FEW HRRR RUNS STILL TRY TO CRANK OUT SCATTERED
CONVECTIVE SHOWERS AND T-STORMS WITH THIS FEATURE AS IT DIPS INTO
THE COASTAL PLAIN VERY LATE TONIGHT. PREVIOUS DISCUSSION FROM 730 PM
FOLLOWS...
A HOT AIRMASS COVERS THE CAROLINAS THIS EVENING. 850 MB TEMPS AROUND
+20C USUALLY EQUATES TO UPPER 90S INLAND FROM THE COAST AND TODAY`S
HOT TEMPERATURES OF 97 IN FLORENCE AND LUMBERTON WERE EXPECTED. AN
UPPER LEVEL RIDGE CENTERED OVER MISSISSIPPI IS PRODUCING A NORTHWEST
UPPER WIND OVER THE CAROLINAS. A SERIES OF UPPER LEVEL DISTURBANCES
EMBEDDED WITHIN IN THE 20-25 KT 700-500 MB FLOW ARE PRODUCING WAVES
OF SHOWERS AND THUNDERSTORMS. ONE SUCH WAVE IS APPROACHING
WILMINGTON FROM THE NORTH NOW AND SHOULD BE OFF THE COAST SOUTH OF
CAPE FEAR BY LATE THIS EVENING. A SECOND DISTURBANCE NOW IN
SOUTHWESTERN VIRGINIA AND EASTERN KENTUCKY WILL TAKE A MORE WESTWARD
TRACK...REACHING THE SC PEE DEE AND INTERSTATE 95 CORRIDOR LATE
TONIGHT. THIS IS ALSO WHEN A SYNOPTIC COLD FRONT WILL BEGIN TO EASE
SOUTHWARD THROUGH SOUTHEASTERN NORTH CAROLINA...REACHING
NORTHEASTERN SOUTH CAROLINA BY DAYBREAK SATURDAY.
THUNDERSTORMS SHOULD CONTINUE TO BUILD SOUTHWARD INTO WILMINGTON
OVER THE NEXT FEW HOURS...AND POPS HAVE BEEN RAISED TO 70 PERCENT
FROM BURGAW SOUTH THROUGH WILMINGTON AND WRIGHTSVILLE BEACH. THE
AIRMASS IS MODERATELY UNSTABLE (CAPE AROUND 2000 J/KG) AND THERE IS
ENOUGH HUMIDITY NEAR THE LCL TO ALLOW SURFACE-BASED PARCELS TO REACH
THEIR LFC AND KEEP ON GOING. ACTIVITY WILL BE MUCH MORE SPARSE IN
COVERAGE WESTWARD ACROSS THE SOUTH CAROLINA COASTAL PLAIN WHERE
ENVIRONMENTAL RELATIVE HUMIDITY NEAR THE LCL IS ONLY 50 TO 60%.
OUTSIDE OF AREAS THAT RECEIVE THUNDERSTORMS...TEMPERATURES WILL FALL
QUITE SLOWLY THIS EVENING IN THE HOT AIRMASS. NEAR THE COAST
DEWPOINTS IN THE MID TO UPPER 70S WILL MAINTAIN HEAT INDICES IN THE
AROUND 100 THROUGH 8 PM...AND IN THE 90S UP UNTIL ALMOST MIDNIGHT.
LOWS SHOULD ONLY FALL INTO MID 70S FOR MOST ARES WITH SOME UPPER 70S
NEAR THE BEACHES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...FEATURE OF INTEREST THIS WEEKEND IS A BACK
DOOR COLD FRONT WHICH WILL DROP ACROSS THE AREA FROM NE TO SW ON
SATURDAY. THIS FRONT WILL BE DRIVEN BY AN AMPLIFYING 5H
PATTERN...WITH A STRONG RIDGE GETTING SQUEEZED NORTH ACROSS THE
MIDDLE OF THE COUNTRY BETWEEN TROUGHS ON BOTH COASTS. IT IS THIS
EASTERN TROUGH DIVING SW THROUGH THE WKND THAT PUSHES THE BACK DOOR
FRONT INTO...AND THROUGH...THE CWA SATURDAY. ALTHOUGH THE SURFACE
FRONT CROSSES SATURDAY...STRONG CAA LAGS ABOUT 18 HRS BEHIND...AND
THUS SATURDAY WILL AGAIN BE A WARM DAY LOCALLY. HOWEVER...INCREASED
CLOUDINESS...LOWERED THICKNESSES...AND SHOWERS/STORMS WILL KEEP
TEMPS MUCH COOLER THAN THE PAST FEW DAYS...WITH HIGHS RISING TO
AROUND 90 IN THE FAR NORTH...MID 90S IN THE SOUTHERN PEE DEE. WHILE
FORCING IS NOT STRONG WITH THE FRONT...AND A DIVING UPPER JET WILL
ACTUALLY PUT THE REGION BENEATH THE RFQ...AN UNFAVORABLE POSITION
FOR UPPER SUPPORT...STILL EXPECT CLIMO POP FOR SCT SHOWERS AND TSTMS
THANKS TO PWATS NEAR 2 INCHES AND STRONG SURFACE CONVERGENCE INTO AN
UNSTABLE ENVIRONMENT. ALTHOUGH COOL ADVECTION WILL BEGIN
OVERNIGHT...LOWS WILL REMAIN ABOVE NORMAL...LOW 70S AREA-WIDE.
COOL AND DRY ADVECTION BEGINS IN EARNEST SUNDAY MORNING...AND PWATS
DROP TO LESS THAN 1 INCH...LOWEST NORTH...WITH 850MB TEMPS DROPPING
5C THROUGH THE DAY. LOTS OF LATE-AUGUST SUNSHINE WILL SOMEWHAT
COUNTERACT STRONG CAA...BUT HIGHS SUNDAY WILL LIKELY BE 5-10 DEGREES
COOLER THAN SATURDAY...AND IN FACT ARE EXPECTED TO BE BELOW
NORMAL...LOW 80S FAR NORTH TO UPR 80S IN THE SOUTH. A FEW SHOWERS
ARE POSSIBLE...ESPECIALLY EARLY IN THE DAY ACROSS THE SC ZONES
CLOSER TO THE FRONT...BUT ACTIVITY WILL NOT BE WIDESPREAD OR STRONG.
MUCH COOLER MINS SUNDAY NIGHT WITH MID 60S EXPECTED FAR NORTH IN THE
DRY COLUMN...UPPER 60S NEAR THE SOUTH SANTEE RIVER AND ON THE
BEACHES.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 PM FRIDAY...THE EXTENDED FORECAST WILL GENERALLY BE DRY
AND SEASONABLE AS A MID LEVEL RIDGE INITIALLY OVER THE MISSISSIPPI
VALLEY SHIFTS TO MORE OF A SOUTHERN POSITION BY THE END OF THE
PERIOD. AT THE SURFACE...HIGH PRESSURE WILL WEDGE DOWN THE EAST
COAST AND EXTEND DOWN INTO GEORGIA FOR MONDAY THROUGH WEDNESDAY.
BEYOND THIS...THE FEATURE BREAKS DOWN LEAVING A WEAK PATTERN AT
THE SURFACE AND ISOLATED SHOWERS AND THUNDERSTORMS MAKE AN
APPEARANCE IN THE FORECAST. THE CHANCES WILL NOT BE GOOD UNTIL
FRIDAY WHEN ANOTHER FRONT DROPS INTO THE REGION PROVIDING A BETTER
FOCUS. TEMPERATURES WILL BE SLIGHTLY BELOW CLIMATOLOGY MONDAY
THROUGH WEDNESDAY WITH THE AXIS OF SURFACE HIGH PRESSURE PROVIDING
A COOL NORTHEAST FLOW. THURSDAY AND FRIDAY SEE MODERATING VALUES
CLOSER TO OR EVEN A BIT ABOVE NORMAL.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...KILM IS THE COOL SPOT ACROSS THE CWA TONIGHT THANKS TO
THE EARLIER TORRENTIAL RAINFALL. HAVE INCLUDED TEMPO MVFR VSBYS FOR
KILM IN THE EARLY MORNING HOURS...BUT INCREASING MID/HIGH CLOUDS
OVERNIGHT SHOULD AGAIN LOWER THE FOG THREAT. DESPITE DEWPOINTS IN
THE UPPER 70S AT KCRE/KMYR...SFC WINDS WILL LIKELY INHIBIT BR
FORMATION AT THESE TERMS. CONVECTION OVER CENTRAL NC ASSOCIATED WITH
ANOTHER UPPER DISTURBANCE IS MOVING TOWARD OUR AREA...BUT THE HRRR
TENDS TO WEAKEN THE ACTIVITY AS IT NEARS THE CWA. THEREFORE WILL NOT
MENTION VCSH DURING THE OVERNIGHT HOURS.
A COLD FRONT WILL DROP SOUTHWARD ACROSS NC THIS MORNING...
APPROACHING KLBT/KILM AROUND 12Z. MODELS SUGGEST THE FRONT MAY GET
HUNG UP ACROSS OUR CWA DURING THE DAY BEFORE CLEARING THE CAROLINAS
LATER IN THE PERIOD. WE COULD SEE SOME SHOWERS ACROSS OUR NORTHERN
ZONES THIS MORNING...BUT CONFIDENCE IS FAIRLY LOW. BETTER CHANCES
FOR CONVECTION WILL BE THIS AFTN WITH THE FRONT LINGERING OVER THE
AREA...ENHANCED BY SEA BREEZE AND BOUNDARY COLLISIONS. HAVE INCLUDED
VCSH FOR ALL TERMS AFTER 18Z. LIGHT/VRBL WINDS IN THE EARLY MORNING
WILL BECOME NORTH AND THEN NORTHEAST BEHIND THE FRONT...REMAINING
BELOW 10 KT. KCRE/KMYR WILL LIKELY SEE E-SE WINDS IN THE AFTN BEHIND
THE SEA BREEZE BEFORE THE FRONT PASSES THROUGH.
EXTENDED OUTLOOK...MVFR/IFR CIGS/VSBYS POSSIBLE ON SUN MORNING.
OTHERWISE EXPECT VFR TO PREVAIL SUN THROUGH WED AS HIGH PRESSURE
RIDGES OVER THE EAST COAST IN THE WAKE OF A COLD FRONT.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1:40 AM SATURDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. RELEVANT PORTION OF PREVIOUS DISCUSSION FOLLOWS
BELOW:
ISOLATED SHOWERS AND T-STORMS COULD DEVELOP LATER TONIGHT AS A
SECOND UPPER LEVEL DISTURBANCE APPROACHES FROM THE NORTH. A COLD
FRONT ACROSS NORTH-CENTRAL NORTH CAROLINA WILL SINK SOUTHWARD
OVERNIGHT...REACHING AS FAR SOUTH AS MYRTLE BEACH BY DAYBREAK
SATURDAY. UNTIL THEN...SOUTHWEST WINDS 10-15 KNOTS ARE EXPECTED
ALONG WITH 2 FOOT SEAS...EVENLY SPLIT BETWEEN A SOUTHEASTERLY
SWELL AND A SOUTHWEST WIND CHOP. SCATTERED THUNDERSTORMS AHEAD OF
THE FRONT WILL BE MOST NUMEROUS THIS EVENING IN THE CAPE FEAR-AREA
WATERS. ANY STORMS WILL BE CAPABLE OF PRODUCING GUSTY OUTFLOW
WINDS AND PLENTY OF LIGHTNING. ALTHOUGH COVERAGE WILL DIMINISH
OVERNIGHT THE CHANCES OF ADDITIONAL POP-UP STORMS WILL CONTINUE
THROUGH DAYBREAK...SHIFTING SOUTHWARD TO THE SOUTH CAROLINA WATERS
WITH THE FRONT.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...BACK DOOR COLD FRONT WILL DROP ACROSS THE
WATERS FROM NE TO SW DURING SATURDAY...CAUSING A WIND SHIFT TO THE
N/NE BEHIND THIS BOUNDARY. WIND SHIFT WILL OCCUR FIRST ACROSS THE
FAR NORTHERN LEGS OFF THE CAPE FEAR COAST...WITH WINDS BECOMING N
THEN NE SATURDAY MORNING...WITH THE WATERS OFF GEORGETOWN COUNTY NOT
EXPERIENCING THE WIND SHIFT UNTIL SATURDAY NIGHT. THE GRADIENT
REMAINS RELAXED SATURDAY...SO WIND SPEEDS THROUGH THIS FRONTAL
PASSAGE WILL BE 5-10 KTS REGARDLESS OF DIRECTION. VERY LATE SATURDAY
NIGHT AND ESPECIALLY ON SUNDAY...A NE SURGE OCCURS AND WINDS QUICKLY
RISE TO 15-25 KTS ACROSS THE WATERS. SEAS THROUGH THE WKND WILL BE
PRIMARILY WIND DRIVEN...RISING FROM 2-3 FT SATURDAY...TO 4-6 FT ON
SUNDAY...AND A SMALL CRAFT ADVISORY MAY BE NEEDED.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...EXPECT NORTHEAST WINDS THROUGH THE PERIOD
COURTESY OF HIGH PRESSURE ALIGNED ALONG THE EASTERN SEABOARD. WIND
SPEEDS WILL BE 15-20 KNOTS MONDAY INTO MIDDAY TUESDAY RETREATING
FROM THAT POINT ON TO SINGLE DIGITS BY LATER WEDNESDAY. LOWER
CONFIDENCE IN SEAS AS THE SPECTRUM IS HIGHLY DEPENDENT ON HOW
INVEST AL96 DOES. CURRENTLY THERE IS A FEW SIX FOOTERS ACROSS THE
OUTER WATERS OF AMZ252 BUT OTHERWISE THE SEAS ARE 3-5 FEET. IF THE
SYSTEM DEVELOPS MORE THAN ANTICIPATED THE SWELL ADDED TO THE
SPECTRUM COULD INCREASE THE SIGNIFICANT SEAS.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JDW
NEAR TERM...REK/TRA
SHORT TERM...JDW
LONG TERM...SHK
AVIATION...BJR
MARINE...REK/TRA/JDW/SHK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
259 PM CDT SAT AUG 23 2014
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 300 PM CDT SAT AUG 23 2014
THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE HEAVY
RAIN LATE THIS AFTERNOON AND THIS EVENING. THEN ENDING ACROSS THE
SOUTH LATE THIS EVENING BUT CONTINUING ACROSS THE NORTH INTO
SUNDAY.
LATEST RADAR ESTIMATES HAVE MATCHED UP WELL WITH OBSERVED REPORTS
ACROSS SOUTHWEST NORTH DAKOTA. GENERALLY 1 TO 1.5 INCHES REPORTED
SOUTH AND WEST OF A LINE FROM SELFRIDGE TO THEODORE ROOSEVELT NP.
DID GET A REPORT FROM WFO BILLINGS OF CLOSER TO 5 INCHES NEAR
BAKER MT. AS OF YET CALLS TO SPOTTERS AND BOWMAN EM HAVE RESULTED
IN NO SIGNIFICANT FLOODING ISSUES. HOWEVER...WE HAVE ISSUED AN
AREAL FLOOD ADVISORY SOUTH AND WEST OF LAKE SAKAKAWEA AND THE
MISSOURI RIVER...TO COVER THE 1 TO 1.5 INCHES OF RAIN THAT HAS
FALLEN IN ADDITION TO ADDITIONAL EXPECTED RAIN THROUGH THE
AFTERNOON AND TONIGHT.
REGARDING THE CURRENT FLOOD WATCH AND POTENTIAL OF SEVERE
WEATHER...
WILL LET THE WATCH CONTINUE. HEAVIEST RAIN HAS FALLEN
ACROSS THE MOST SATURATED SOILS IN THE SOUTHWEST. THE HEAVIEST
ADDITIONAL ACCUMULATIONS TONIGHT SHOULD BE CENTERED ACROSS THE
NORTH CENTRAL AND NORTHWEST. IF WE HAD TO PARE IT DOWN...WOULD
PROBABLY REMOVE WELLS SOUTH THROUGH MCINTOSH. HOWEVER...THERE IS
STILL A THREAT OF AFTERNOON AND EVENING CONVECTION HERE AS THE
SURFACE LOW LIFTS INTO NORTH DAKOTA. THUS WILL CONTINUE AS IS FOR
NOW. THE LATEST HRRR STILL DEVELOPS SCATTERED CONVECTION IN THIS
AREA THIS EVENING. HOWEVER THE STRONGEST CONVECTION IS NOW BEING
PLACED TO THE SOUTH OF THE CWA. WITH OUR EAST TO NORTHEAST FLOW AND
COOLER TEMPERATURES OVER NORTH DAKOTA THIS SEEMS REASONABLE...BUT
WITH THE SURFACE LOW LIFTING INTO CENTRAL NORTH DAKOTA THINK OUR
SOUTHEAST CWA WILL BE IN A FAVORED LOCATION FOR ABUNDANT LOW LEVEL
HELICITY THUS WILL CONTINUE A MENTION OF SEVERE OVER THE SOUTHEAST
CWA.
WE DRY OUT FROM SOUTH TO NORTH LATE THIS EVENING THROUGH SUNDAY.
HIGHEST POPS WILL REMAIN OVER THE NORTHWEST AND FAR NORTH CENTRAL.
WITH THE UPPER LEVEL SLOW LIFTING THROUGH EASTERN MONTANA INTO
NORTHWEST ND...THERE SHOULD STILL BE ENOUGH MID TO UPPER LEVEL
FORCING TO MENTION ISOLATED THUNDER THROUGH THE DAY WHEREVER WE
HAVE A MENTION OF SHOWERS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 PM CDT SAT AUG 23 2014
SUNDAY EVENING THE UPPER LEVEL LOW IS PROGGED TO BE AT THE BORDER OF
MONTANA AND NORTH DAKOTA...WITH THE SURFACE LOW ALONG THE NORTH
DAKOTA/CANADIAN/MINNESOTA BORDER. THE ELONGATED SURFACE LOW/FRONT
COMBINED WITH THE UPPER LOW TO THE WEST WILL KEEP HIGH CHANCES OF
SHOWERS IN THE NORTHWEST/NORTH CENTRAL SUNDAY NIGHT.
THE SYSTEM LIFTS NORTHEASTWARD SUNDAY NIGHT AND INTO MONDAY...WITH
COLD ADVECTION IN ITS WAKE. LOOKING AT LOWS SUNDAY NIGHT IN THE 40S
WEST TO LOWER 50S IN THE JAMES VALLEY. MOSTLY CLOUDY SKIES NORTH
MONDAY WILL KEEP MAXIMUM TEMPERATURES CONFINED TO THE UPPER 50S WITH
60S SOUTH. BY TUESDAY MORNING THE SURFACE HIGH SETTLES OVER NORTH
DAKOTA...AND LOW TEMPERATURES SHOULD BE IN THE 40S ACROSS WESTERN
AND CENTRAL NORTH DAKOTA.
DURING THE DAY TUESDAY THROUGH WEDNESDAY THE TRAILING UPPER LEVEL
TROUGH MOVES EAST ACROSS THE NORTHERN PLAINS...WITH ISOLATED TO
SCATTERED SHOWERS POSSIBLE. MINOR UPPER LEVEL RIDGING OCCURS
WEDNESDAY NIGHT THROUGH FRIDAY. THE APPROACH OF ANOTHER ROCKIES
TROUGH TOWARDS NEXT WEEKEND MAY BE THE NEXT CHANCE OF SHOWERS AND
THUNDERSTORMS. A SLOW WARMING TREND WITH HIGHS TUESDAY IN THE 60S
WARMING TO THE 80S BY FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 300 PM CDT SAT AUG 23 2014
MAINLY IFR CEILINGS EXPECTED THROUGH THE FORECAST PERIOD WITH
OCCASIONAL MVFR VISIBILITIES IN HEAVIER SHOWERS. COULD SEE PERIODS
OF MVFR CEILINGS THIS AFTERNOON...THEN AGAIN LATE SUNDAY MORNING
AS THE STRONG LOW LIFTS OUT OF THE AREA. OTHERWISE EXPECT IFR TO
OCCASIONALLY LIFR. WINDS WILL BE VARIABLE WITH THE SURFACE LOW
EXPECTED TO LIFT THROUGH WESTERN NORTH DAKOTA...BUT MAINLY EAST TO
SOUTHEAST TODAY AND THIS EVENING...SHIFTING WESTERLY FROM SOUTH TO
NORTH ON SUNDAY. SPEEDS GENERALLY 10 TO 25 KNOTS.
&&
.HYDROLOGY...
ISSUED AT 300 PM CDT SAT AUG 23 2014
MODERATE TO HEAVY RAINS OVER THE PAST WEEK HAVE KEPT SOIL MOISTURE
ABNORMALLY HIGH ACROSS WESTERN AND CENTRAL NORTH DAKOTA. RAINFALL
THAT OCCURRED TODAY...ALONG WITH THE EXPECTED RAINFALL INTO TONIGHT
MAY LIKELY LEAD TO SOME OVERLAND FLOODING...ALONG WITH INCREASED
FLOWS INTO CREEKS...STREAMS...AND RIVERS.
ALONG WITH THE FLOOD WATCH THAT WAS ISSUED ON FRIDAY FOR TODAY
THROUGH SUNDAY...HAVE ALSO ISSUED AN AREAL FLOOD ADVISORY FOR THE
AREA SOUTH AND WEST OF THE MISSOURI RIVER. RADAR ESTIMATES WERE IN
AGREEMENT WITH SOME RAINFALL REPORTS OF 1 TO 1.5 INCHES OF RAINFALL
SO FAR TODAY. IN ADDITION...WHILE THERE IS NO REASONABLE EXPECTATION
OF MAJOR RIVER FLOODING...AT A MINIMUM THERE WILL BE SIGNIFICANT
WITHIN BANK RISES...AND MINOR RIVER FLOODING CANNOT BE RULED OUT.
.BIS WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY AFTERNOON FOR NDZ001>005-009>013-
017>023-031>036-040>047-050.
&&
$$
SHORT TERM...TWH
LONG TERM...JV
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
220 PM EDT SAT AUG 23 2014
.SYNOPSIS...
UPPER RIDGING WILL SLOWLY BUILD OVER THE REGION BY
SUNDAY...BRINGING AN END TO THE RECENT SIEGE OF SHOWER AND
THUNDERSTORM ACTIVITY. THE UPPER RIDGE WILL DOMINATE THE WEATHER
PATTERN OVER THE NORTHEAST UNITED STATES AND SOUTHEASTERN CANADA
DURING THE EARLY AND MIDDLE PART OF THE UPCOMING WEEK...WITH THE
NEXT CHANCE OF RAINFALL NOT ARRIVING UNTIL LATE WEDNESDAY OR
THURSDAY FROM AN APPROACHING MIDWESTERN FRONTAL SYSTEM.
&&
.NEAR TERM /THROUGH TONIGHT/...
SATELLITE SHOWS SOME BREAKS IN THE OVERCAST OVER THE FAR WESTERN
PERIPHERY OF MY FCST AREA...WHICH IS WHERE WE ARE MANAGING TO
DEVELOP SOME CAPE. WITH THE PERSISTENT LOW LEVEL CONVERGENCE AND
EASTERLY UPSLOPE FLOW...SCATTERED CONVECTION IS BEGINNING TO POP
IN THIS SLIGHTLY ELEVATED INSTABILITY FROM MCKEAN COUNTY DOWN
THROUGH WESTERN CAMBRIA AND SOMERSET COUNTIES.
LATEST HRRR DOESN`T SHOW ANY PARTICULAR AREA FAVORING ANY KIND OF
REAL ORGANIZATION OF THE CONVECTION INTO THE LATE AFTERNOON
HOURS...BUT WE HAVE SEEN SOME OF THE SHOWERS BE VERY
EFFICIENT...PRODUCING LOCALLY HEAVY RAINS.
THE PERSISTENT...AND ANOMALOUS SFC-850 MB EAST TO SERLY FLOW AND
HIGH PWAT AIR WILL AT LEAST MAINTAIN WIDESPREAD/THICK CLOUD COVER
AND UNSEASONABLY COOL TEMPS...EXCEPT OVER THOSE FAR WESTERN AREAS
WHERE A BIT OF SUNSHINE WILL HELP PUSH TEMPS INTO THE LOWER TO MID
70S.
THE LARGE SCALE PATTERN IS ADVERTISED TO CHANGE ONLY SLOWLY OVER
THE NEXT 12-18 HOURS...WITH DRIER AIR EVENTUALLY SLIDING DOWN OUT
OF THE NORTH AND SHOVING THE HIGHER MOISTURE BACK TO OUR SOUTH AND
WEST.
MOSTLY CLOUDY SKIES WILL PERSIST FOR MUCH OR PERHAPS ALL OF THE
OVERNIGHT WITH A CHANCE OF LIGHT RAIN OR DRIZZLE MAINLY BEFORE
MIDNIGHT...AND ACROSS THE SW CORNER OF THE CWA.
ANY CLEARING LATE TONIGHT WILL COMBINE WITH THE MOIST GROUND AND
LIGHT WIND TO PRODUCE AREAS OF FOG...THAT WILL BECOME LOCALLY
DENSE AFTER MIDNIGHT. LOW TEMPS EARLY SUNDAY WILL RANGE FROM THE
MID 50S ACROSS THE NORTH...TO AROUND 60F IN THE SOUTHERN VALLEYS.
&&
.SHORT TERM /SUNDAY/...
DRIER AIR WILL SETTLE OVER THE AREA SUNDAY BRINGING A MUCH
ANTICIPATED BREAK FROM THE RECENT ALMOST DAILY ASSAULT OF SHOWERS
AND THUNDERSTORMS. CANNOT RULE OUT A LINGERING SHOWER OR DRIZZLE
OVER THE SWRN AREAS IN THE AREA OF BEST LOW LEVEL UPSLOPE
FLOW...BUT OVERALL TREND WILL BE FOR MOST LOCATIONS TO SEE A
RAIN-FREE DAY FOR A CHANGE.
AREAS OF MORNING CLOUDS AND PERHAPS SOME PATCHY LIGHT DRIZZLE...
WILL TRANSITION INTO INCREASINGLY SUNNY SKIES DURING THE MIDDAY
AND AFTERNOON HOURS SUNDAY. TEMPS SUNDAY WILL REBOUND NICELY FROM
SATURDAY/S CHILL WITH AFTERNOON HIGHS IN THE MID 70S ACROSS THE
MTNS...AND AROUND 80F THROUGHOUT THE SUSQ VALLEY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
MUCH OF THE EXTENDED WILL FEATURE A BIG RIDGE DOMINATING THE
PATTERN OVER THE EASTERN AND NORTHEASTERN US. FAIR WEATHER WILL
DEVELOP ALONG WITH WARMING TEMPERATURES AS THE RIDGE ESTABLISHES
ITSELF AND MAINTAINS ITS HOLD UNTIL AT LEAST LATER WEDNESDAY-THURSDAY
WHEN THE NEXT FRONTAL SYSTEM IS ADVERTISED TO APPROACH.
500 HEIGHTS IN EXCESS OF 5900M ARE FCST TO POKE INTO PA BY LATER
MONDAY AND CONTINUE INTO WED. THIS WILL ASSURE THE FIRST DAYS OF
THE NEW SCHOOL YEAR WILL BE WARM AND FAIRLY UNCOMFORTABLE.
THE OPERATIONAL GFS AND ECMWF KEEP US DRY THROUGH AT LEAST LATER
WEDNESDAY WHILE THE GEFS CONTINUES THE TREND TOWARD BEING MORE
PESSIMISTIC...BRINGING MEASURABLE RAINS EAST QUICKER UNDER A
FLATTER UPPER FLOW.
IT SEEMS THE RESOLUTION OF THE TROPICAL SYSTEM IS PLAYING A ROLE
IN THE EXTENDED FORECASTS FOR THE GFS/GEFS VS THE ECMWF. THE ECMWF
HUSTLES A TROPICAL STORM OFF THE EAST COAST FASTER THAN THE
GFS...WHICH ALLOWS IT TO REBUILD THE EASTERN RIDGE QUICKER. STILL
TOO MUCH UNCERTAINTY TO LATCH ONTO ANY SOLID SOLUTION. WILL KEEP
THE CURRENT BLAND CHANCE OF SHOWERS STARTING WEDNESDAY NIGHT
LASTING INTO AT LEAST THURSDAY NIGHT.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
STILL HAVE LOW CIGS ACROSS THE AREA AND NOT MUCH CHANGES EXPECTED
THIS AFTERNOON. WIDELY SCATTERED SHOWER ACTIVITY ACROSS THE
ENTIRE AREA. FOG AND CEILING RESTRICTIONS WILL AGAIN OVERSPREAD
THE AREA TONIGHT.
IN THE LONGER RUN...HIGH PRESSURE WILL SLOWLY BUILD INTO THE
NORTHEAST ON SUNDAY CONTINUING INTO MID WEEK. FRONT APPROACHING
LATER WEDNESDAY AND THURSDAY MAY BRING THE NEXT ROUND OF
SHRA/TSRA.
OUTLOOK...
SUN...LOW CIGS AND FOG EARLY...THEN VFR
MON- WED...MORNING RESTRICTIONS FROM FOG POSSIBLE...OTHERWISE
VFR.
THU...RESTRICTIONS POSSIBLE WITH THUNDERSTORMS AND A COLD FRONT.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LA CORTE
AVIATION...JUNG/ROSS
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
902 PM CDT SUN AUG 24 2014
.DISCUSSION...
SKIES ARE MOSTLY CLEAR OVER MUCH OF THE FORECAST AREA THIS EVENING
WITH TEMPERATURES RANGING FROM THE LOWER 70S TO MID 80S. ALL OF
THE THUNDERSTORM ACTIVITY THAT WAS OVER THE FORECAST AREA EARLIER
THIS EVENING HAS ENDED AND NO ADDITIONAL THUNDERSTORMS ARE
EXPECTED FOR THE REMAINDER OF TONIGHT. WILL UPDATE FORECAST TO
REMOVE ANY MENTION OF RAIN TONIGHT.
ARS
&&
.PREV DISCUSSION... /ISSUED 615 PM CDT SUN AUG 24 2014/
UPDATE...
UPDATED TO EXTEND AFTERNOON RAIN CHANCES TO WEST OF THE MS RIVER.
DISCUSSION...
NQA RADAR BACK IN SERVICE AND JUST IN TIME TO SHOW CONVECTION
DEVELOPING IN NORTH MISSISSIPPI. TEMPERATURES WERE MAINLY IN THE
90S ACROSS THE MIDSOUTH WITH A RECORD 100 DEGREES...THE WARMEST
READING SINCE AUGUST 2012...AT THE MEMPHIS INTERNATIONAL AIRPORT.
FOR THE REMAINDER OF TODAY AND TONIGHT...SHORT TERM HRRR MODEL
SHOWING CONVECTION BECOMING SCATTERED BY 4 PM FOR POINTS ALONG
AND WEST OF THE MISSISSIPPI RIVER...WHICH CURRENTLY LINES UP WITH
PW`S ABOVE 1.80 INCHES. COULDN`T RULE OUT AN ISOLATED WET
MICROBURST WITH THE STRONGEST STORMS. ACTIVITY WILL WANE BY 9 PM
LEAVING SKIES PARTLY CLOUDY OVERNIGHT. THIS SHOULD HELP KEEP MORE
HEAT IN...WITH OVERNIGHT LOWS AGAIN IN THE MID AND UPPER 70S.
MONDAY AND TUESDAY...A WEAK DISTURBANCE WILL MOVE WESTWARD ALONG
THE GULF COAST/SOUTHSIDE OF THE UPPER RIDGE...AND AS IT DOES
EASTERLY WINDS IN THE BOUNDARY LAYER AND MIDLEVELS WILL SLIDE
DRIER AIR OFF THE APPALACHIANS IN ITS WAKE. HEAT INDICES WILL
CONTINUE TO FLIRT WITH 105F TOMORROW...DESPITE MORE CLOUD COVER
AND CONVECTION. FEEL BY TUESDAY ENOUGH DRY AIR WILL HAVE
OVERSPREAD THE MIDSOUTH TO REDUCE HEAT INDICES BELOW 105F.
ISOLATED STORMS WILL BE POSSIBLE ON TUESDAY BUT MAINLY WEST OF THE
MISSISSIPPI RIVER NEAR THE FRONT EDGE OF THE DRIER AIR.
WEDNESDAY THROUGH FRIDAY...MODELS ARE IN GOOD AGREEMENT THAT THE
UPPER RIDGE WILL REMAIN OVER THE REGION...BUT STRONGER SUBSIDENCE
WILL KEEP DEWPOINTS IN THE 60S AND LOWER RAIN CHANCES TO AROUND 10
PERCENT. TEMPERATURES WILL BE IN THE LOW TO MID 90S WITH AFTERNOON
HEAT INDICES IN THE 93-100F RANGE.
NEXT WEEKEND...THE GFS AND EURO ARE BECOMING BETTER ALIGNED THAT
THE RIDGE WILL FLATTEN IN RESPONSE TO AN APPROACHING CENTRAL
PLAINS SHORTWAVE. THIS DISTURBANCE NOW APPEARS SOMEWHAT WEAKER AND
OUT OF PHASE WITH THE MAIN UPPER LEVEL FLOW. NONETHELESS MOISTURE
OUT AHEAD OF THE SYSTEM WILL MOVE OVER THE OZARKS ON SATURDAY AND
INTO THE MIDSOUTH BY EARLY SUNDAY. HAVE BUMPED UP TEMPERATURES TO
MAINLY THE LOW 90S FOR HIGHS AND KEPT A CONSERVATIVE APPROACH TO
THE RAIN CHANCES.
JAB
&&
.AVIATION...
00Z TAF CYCLE (25/00Z-26/00Z)
LINGERING TSRA ARE EXPECTED TO DISSIPATE THIS EVENING AROUND 01Z.
ISOLATED TO SCATTERED TSRA ARE EXPECTED TO DEVELOP MONDAY AFTERNOON
AROUND THE KMEM...KMKL...AND KTUP TAF SITES...MENTIONED VCTS FOR
THESE SITES. OTHERWISE VFR CONDITIONS WILL PREVAIL DURING THE
PERIOD...THE EXCEPTION POSSIBLY BEING MVFR CONDITIONS IN FOG AT KMKL
EARLY MONDAY MORNING. WINDS LIGHT AND VARIABLE TONIGHT. WINDS MONDAY
E-SE 4-6 KTS.
JCL
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR ALCORN-BENTON MS-CALHOUN-
CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-MARSHALL-
MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-TALLAHATCHIE-TATE-
TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR BENTON TN-CARROLL-
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
617 PM CDT SUN AUG 24 2014
.UPDATE...ADDED AVIATION SECTION FOR 00Z TAF`S.
&&
.AVIATION...BNA/CKV/CSV...SURFACE RIDGE IS SITUATED DIRECTLY OVER
MIDDLE TENNESSEE THIS EVENING, WITH VERY LITTLE ACTIVITY OCCURRING
ACROSS THE MID STATE AT THIS TIME. HRRR SUGGESTS THAT WE CAN
EXPECT NOTHING OVERNIGHT, ALTHOUGH LOOK FOR RADIATION FOG TO
DEVELOP AT CKV AND CSV AFTER 06Z. RIDGE WILL SHIFT TO OUR EAST
TOMORROW AFTERNOON, WITH VERY LIGHT WINDS THE NEXT 24 HRS.
ISOLATED STORMS ARE POSSIBLE MONDAY AFTERNOON, AND WILL ADDRESS
THIS WITH VCTS/CB REMARKS FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 243 PM CDT SUN AUG 24 2014/
DISCUSSION...
LAST NIGHT/S WIDE SPREAD RAINFALL AND THIS MORNING/S LEFTOVER
CLOUDS AND SHOWERS HELPED KEEP 19Z TEMPERATURES 5 TO 10 DEGREES
LOWER THAN 24 HOURS AGO...ESPECIALLY ON THE PLATEAU WHERE THICKEST
CLOUDS CONTINUED. HEAT ADVISORY FOR THE WESTERN 2/3 OF MIDDLE TN
EXPIRES AT 02Z TONIGHT BUT MAY CANCEL IT EARLY DEPENDING ON 20Z
AND 21Z HEAT INDEX VALUES.
THE LOWER TEMPS ARE HELPING DELAY TSRA DEVELOPMENT SO FAR TODAY.
STILL EXPECT SOME STORMS TO FORM LATER THIS AFTERNOON INTO THIS
EVENING BUT POPS MAINLY IN THE SLIGHT CHANCE RANGE. ANY STORMS
SHOULD DRIFT SLOWLY SOUTHWESTWARD. STORM POTENTIAL SHOULD DECREASE
BY MIDNIGHT. PATCHY FOG HAS OCCURRED THE PAST FEW MORNINGS AND
EXPECT A REPEAT LATE TONIGHT AND EARLY MONDAY...MAINLY BY BODIES
OF WATER.
WEATHER PATTERN FOR THE WEEK AHEAD... THE HIGH AMPLITUDE H5 RIDGE
AXIS WAS STILL OVER THE MS RIVER VALLEY TODAY. THE RIDGE WILL
FLATTEN AND WEAKEN SOMEWHAT OVER THE NEXT FEW DAYS AS A STRONG
TROF MOVES EASTWARD ACROSS THE NORTHERN U.S. AND SOUTHERN CANADA.
THUS...TODAY/S LIGHT NORTHEASTERLY H5 FLOW WILL BECOME EASTERLY ON
MONDAY AND THEN LIGHT/VARIABLE TUESDAY AND WEDNESDAY WHEN THE
RIDGE AXIS IS ORIENTED ALONG LENGTH OF TN. BY LATE IN THE WEEK...
THE SLIGHTLY WEAKENED H5 RIDGE WILL MOVE OVER THE SOUTHEASTERN
U.S. BEFORE POSSIBLY YIELDING TO A WEAK TROF NEXT WEEKEND.
THE DETAILS FOR THE WEEK AHEAD... LOW POPS WARRANTED MONDAY MAINLY
ACROSS THE SOUTH AND THE HIGHER TERRAIN OF THE EAST WHERE MODELS
FORECAST DEEPER MOISTURE. DO NOT EXPECT ANY SIGNIFICANT RAIN
TUESDAY OR WEDNESDAY AS H5 RIDGE AXIS SITS OVER THE STATE. RAIN
CHANCES WILL REAPPEAR ON THURSDAY WITH THE POTENTIAL FOR A WEAK
BACK DOOR FRONT TO APPROACH AS A SFC HIGH BUILDS TO OUR NORTHEAST
IN THE WAKE OF THE PASSING CANADIAN H5 TROF. SLIGHT CHANCE POPS
WILL CONTINUE FRIDAY THROUGH NEXT WEEKEND AS H5 RIDGE SLIDES OVER
SOUTHEAST STATES AND A WEAK H5 TROF APPROACHES FROM THE WEST.
TEMPERATURES WILL STAY ABOVE AVERAGE ALL WEEK WITH MAXES OF 90 TO
95 MOST AREAS. MAX TEMPS COULD START EDGING DOWNWARD A TAD NEXT
WEEKEND AS THE H5 RIDGE WEAKENS AND THE TROF APPROACHES...BUT WE
SHOULD STILL REMAIN ABOVE SEASONAL NORMS. FYI...THE AVERAGE HIGH
IN NASHVILLE IN LATE AUGUST IS 86 DEGREES.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
HEAT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR TNZ005>009-023>030-
056>064-075-077-093>095.
&&
$$
ROSE
AREA FORECAST DISCUSSION...UPDATED
NWS MEMPHIS TN
615 PM CDT SUN AUG 24 2014
.DISCUSSION...
UPDATED TO INCLUDE THE 00Z AVIATION DISCUSSION BELOW.
JCL
&&
.PREV DISCUSSION... /ISSUED 333 PM CDT SUN AUG 24 2014/
UPDATE...
UPDATED TO EXTEND AFTERNOON RAIN CHANCES TO WEST OF THE MS RIVER.
DISCUSSION...
NQA RADAR BACK IN SERVICE AND JUST IN TIME TO SHOW CONVECTION
DEVELOPING IN NORTH MISSISSIPPI. TEMPERATURES WERE MAINLY IN THE
90S ACROSS THE MIDSOUTH WITH A RECORD 100 DEGREES...THE WARMEST
READING SINCE AUGUST 2012...AT THE MEMPHIS INTERNATIONAL AIRPORT.
FOR THE REMAINDER OF TODAY AND TONIGHT...SHORT TERM HRRR MODEL
SHOWING CONVECTION BECOMING SCATTERED BY 4 PM FOR POINTS ALONG
AND WEST OF THE MISSISSIPPI RIVER...WHICH CURRENTLY LINES UP WITH
PW`S ABOVE 1.80 INCHES. COULDN`T RULE OUT AN ISOLATED WET
MICROBURST WITH THE STRONGEST STORMS. ACTIVITY WILL WANE BY 9 PM
LEAVING SKIES PARTLY CLOUDY OVERNIGHT. THIS SHOULD HELP KEEP MORE
HEAT IN...WITH OVERNIGHT LOWS AGAIN IN THE MID AND UPPER 70S.
MONDAY AND TUESDAY...A WEAK DISTURBANCE WILL MOVE WESTWARD ALONG
THE GULF COAST/SOUTHSIDE OF THE UPPER RIDGE...AND AS IT DOES
EASTERLY WINDS IN THE BOUNDARY LAYER AND MIDLEVELS WILL SLIDE
DRIER AIR OFF THE APPALACHIANS IN ITS WAKE. HEAT INDICES WILL
CONTINUE TO FLIRT WITH 105F TOMORROW...DESPITE MORE CLOUD COVER
AND CONVECTION. FEEL BY TUESDAY ENOUGH DRY AIR WILL HAVE
OVERSPREAD THE MIDSOUTH TO REDUCE HEAT INDICES BELOW 105F.
ISOLATED STORMS WILL BE POSSIBLE ON TUESDAY BUT MAINLY WEST OF THE
MISSISSIPPI RIVER NEAR THE FRONT EDGE OF THE DRIER AIR.
WEDNESDAY THROUGH FRIDAY...MODELS ARE IN GOOD AGREEMENT THAT THE
UPPER RIDGE WILL REMAIN OVER THE REGION...BUT STRONGER SUBSIDENCE
WILL KEEP DEWPOINTS IN THE 60S AND LOWER RAIN CHANCES TO AROUND 10
PERCENT. TEMPERATURES WILL BE IN THE LOW TO MID 90S WITH AFTERNOON
HEAT INDICES IN THE 93-100F RANGE.
NEXT WEEKEND...THE GFS AND EURO ARE BECOMING BETTER ALIGNED THAT
THE RIDGE WILL FLATTEN IN RESPONSE TO AN APPROACHING CENTRAL
PLAINS SHORTWAVE. THIS DISTURBANCE NOW APPEARS SOMEWHAT WEAKER AND
OUT OF PHASE WITH THE MAIN UPPER LEVEL FLOW. NONETHELESS MOISTURE
OUT AHEAD OF THE SYSTEM WILL MOVE OVER THE OZARKS ON SATURDAY AND
INTO THE MIDSOUTH BY EARLY SUNDAY. HAVE BUMPED UP TEMPERATURES TO
MAINLY THE LOW 90S FOR HIGHS AND KEPT A CONSERVATIVE APPROACH TO
THE RAIN CHANCES.
JAB
&&
.AVIATION...
00Z TAF CYCLE (25/00Z-26/00Z)
LINGERING TSRA ARE EXPECTED TO DISSIPATE THIS EVENING AROUND 01Z.
ISOLATED TO SCATTERED TSRA ARE EXPECTED TO DEVELOP MONDAY AFTERNOON
AROUND THE KMEM...KMKL...AND KTUP TAF SITES...MENTIONED VCTS FOR
THESE SITES. OTHERWISE VFR CONDITIONS WILL PREVAIL DURING THE
PERIOD...THE EXCEPTION POSSIBLY BEING MVFR CONDITIONS IN FOG AT KMKL
EARLY MONDAY MORNING. WINDS LIGHT AND VARIABLE TONIGHT. WINDS MONDAY
E-SE 4-6 KTS.
JCL
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR ALCORN-BENTON MS-CALHOUN-
CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-MARSHALL-
MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-TALLAHATCHIE-TATE-
TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR BENTON TN-CARROLL-
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
725 PM CDT SUN AUG 24 2014
.UPDATE...
QUICK UPDATE TO ADJUST POP/WX/QPF GRIDS THROUGH THIS EVENING TO
BETTER CORRESPOND TO CURRENT RADAR TRENDS. MOST NOTABLY...
INCREASED POPS INTO THE CHANCE AND LIKELY CATEGORIES ACROSS A GOOD
PORTION OF THE ROLLING PLAINS WHERE A POORLY ORGANIZED CLUSTER OF
CONVECTION CONTINUES. WE EXPECT AN OVERALL DOWNWARD TREND IN THE
CONVECTION THROUGH THE MID/LATE EVENING HOURS AS THE UNSTABLY AND
DIURNALLY DRIVEN FORCING WANES.
&&
.PREV DISCUSSION... /ISSUED 636 PM CDT SUN AUG 24 2014/
AVIATION...
CURRENT RADAR TRENDS SUGGEST THAT KLBB AND KCDS MAY ESCAPE ANY
-TSRA IN THE NEXT HOUR OR SO...BUT THERE IS STILL AN OUTSIDE
CHANCE. ALSO...SOME GUSTY OUTFLOW WINDS ARE STILL POSSIBLE.
OTHERWISE...VFR CONDITIONS WITH SRLY SURFACE WINDS EXPECTED
THROUGH MID-AFTERNOON MONDAY.
PREV DISCUSSION... /ISSUED 343 PM CDT SUN AUG 24 2014/
SHORT TERM...
DESPITE OF A WESTWARD EXPANSION OF WEAK RIDGING ALOFT AND VERY
LITTLE IF ANY SURFACE FEATURES...AN ADEQUATE BOOST IN THETA-E EARLIER
TODAY SUPPLIED MUCH OF THE AREA WITH DEEPER MOISTURE NECESSARY FOR
SOME DIURNALLY DRIVEN TSTORMS. NON-HIGH RES MODELS HAVE LARGELY
MISSED THE BOAT SO FAR TODAY WITH THE EXPERIMENTAL MODELS PLAYING
THE ROLE OF THE DARK HORSE. RAP DATA SHOW THE RICHEST PWATS OF 1.3
INCHES CONFINED EAST OF A BROWNFIELD TO SILVERTON LINE WITH
GENERALLY ONE INCH OR LESS FARTHER WEST. ENVIRONMENT IN THE RICHER
PWATS IS CHARACTERIZED BY SBCAPES OF 1200-2500 J/KG WITH WEAK SHEAR.
THIS THEME WILL PERSIST THROUGH MID-EVENING AT WHICH POINT TSTORMS
WILL DWINDLE...BUT UNTIL THEN WE EXPECT ADDITIONAL STRONG TO PERHAPS
BRIEFLY SEVERE PULSE MODES WITH MICROBURSTS THE PRIMARY HAZARD.
BY MONDAY MORNING...DEEPER MONSOONAL MOISTURE WILL BE TUGGED NORTH
INTO NEW MEXICO AROUND THE ZONAL RIDGE AXIS STILL POISED FIRMLY OVER
THE SOUTH PLAINS. HEIGHT FIELDS ON THE WESTERN PERIPHERY OF THIS
RIDGE ARE NOT SHOWN TO BUILD ANY...SO THE OPPORTUNITY WILL EXIST FOR
ANOTHER ROUND OF SOLAR-POWERED TSTORMS MAINLY NEAR THE NM STATE LINE
WHERE OCCASIONAL DISTURBANCES ARE PROGGED TO LIFT NORTH FROM
CHIHUAHUA. OTHERWISE...WE CONTINUE TO SIDE WITH THE WARMER SPECTRUM
OF MOS GUIDANCE FOR BOTH LOWS AND HIGHS GIVEN THE RECENT OBSERVED
TRENDS.
LONG TERM...
COOLER WEATHER IS ON THE WAY AS WELL AS A SHOT FOR RAIN. BUT BEFORE
WE GET THERE...WARM AND DRY WEATHER WILL CONTINUE TO DOMINATE US AS
HIGH PRESSURE TO OUR EAST EXTENDS OVER THE REGION. OUR NORTHWESTERN
ZONES WILL HAVE A BIT OF A REPRIEVE MONDAY NIGHT AS A WEAKNESS
PROPAGATES AROUND THE WESTERN EDGE OF THE RIDGE. THE WEAKNESS MAKES
USE OF A SURFACE TROF LOCATED OVER THE SOUTHWESTERN TX PANHANDLE AND
FIRES SCATTERED CONVECTION IN THAT REGION. CHANCES ARE ONLY SLIGHT
AS THE AVAILABLE MONSOONAL MOISTURE ONLY COVERS A VERY SMALL AREA
WHICH COINCIDES WITH THE SURFACE TROF. BY TUESDAY AND INTO
WEDNESDAY...THE RIDGE TO OUR EAST BUILDS FURTHER WEST INHIBITING
CHANCES FOR ANY RAIN...HOWEVER A LOW AWAITS US OVER THE GREAT BASIN
AND IS READY TO MOVE IN AND DEFEAT THE EVIL RIDGE. WITH THE
EXCEPTION OF THE GFS...MODELS HAVE BEEN IN DECENT AGREEMENT WITH
HANDLING OF THE LOW THE PAST SEVERAL RUNS. THE 12Z RUN YIELDED THE
GFS SLOWING THE EASTWARD PROGRESSION OF THE LOW AND IS MORE IN LINE
WITH THE OTHER MODELS. THE LOW WILL INITIALLY START OFF CLOSED AS IT
MOVES ACROSS THE ROCKIES INTO THE CENTRAL PLAINS DURING WHICH TIME
IT WILL SLOWLY BECOME AN OPEN WAVE. BY LATE WEDNESDAY A COLD FRONT
SHOULD BE KNOCKING ON OUR DOOR. THE TIMING OF THE FRONT IS SOMEWHAT
IN QUESTION WITH TIMINGS RANGING FROM EARLY TO LATE THURSDAY...WITH
THURSDAY MORNING BEING THE TIMING CHOICE FOR THE TIME BEING. RAIN
CHANCES WILL EXIST ALONG THE FRONT...ESPECIALLY AS THE UPPER LEVEL
LOW PUSHES INTO THE REGION. PWATS OVER 1.3 INCHES WILL BE MORE THAN
ENOUGH TO AID IN MODERATE RAINFALL AMOUNTS. RAIN CHANCES WILL BE
HIGHEST THURSDAY NIGHT INTO EARLY FRIDAY AS A JET MAX PUSHES IN FROM
THE WEST ON THE SOUTHEAST SIDE OF THE LOW. AS OF NOW THE JET MAX IS
GREATEST OVER OUR SOUTHEASTERN ZONES. THIS COMBINED WITH A DIFFLUENT
UPPER PATTERN SHOULD BE MORE THAN EFFICIENT IN DEVELOPING PRECIP.
THE LOW WILL HAVE AN EXTENDED VISIT AND REMAIN OVERHEAD THROUGH LATE
SUNDAY BEFORE ZONAL FLOW TAKES OVER. TEMPERATURES WILL BE RELATIVELY
COOL IN THE SENSE OF TEMPS WILL BE AROUND SEASONAL AVERAGES BUT
COOLER THAN THEY WILL BE EARLIER THIS WEEK. DEPENDING ON THE
STRENGTH OF THE FRONT...SOME AREAS SUCH AS THE TEXAS PANHANDLE MAY
SEE BELOW AVERAGE TEMPS AS COOL AIR OVER MT INTO CA WILL BE PUSHED
SOUTHWARD. AS OF THIS AFTERNOON...PARTS OF INTERIOR MT HAVE FAILED
TO REACH INTO THE 50S. AS OF NOW THE COOLEST AIR WITH THE FRONT
LATER THIS WEEK SHOULD STAY TO OUR NORTH WITH THE COOL SIDE OF THE
FORECAST BEING IN THE UPPER 50S.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 65 92 63 90 62 / 10 20 20 10 10
TULIA 69 95 65 93 64 / 20 10 20 10 10
PLAINVIEW 65 95 64 92 64 / 20 10 10 10 10
LEVELLAND 67 94 65 91 64 / 10 10 20 10 10
LUBBOCK 72 96 68 94 68 / 10 10 10 10 10
DENVER CITY 67 95 65 92 65 / 10 10 10 10 10
BROWNFIELD 66 96 66 93 66 / 10 10 10 10 10
CHILDRESS 73 101 72 98 72 / 20 10 10 10 10
SPUR 70 100 68 96 68 / 30 0 10 0 10
ASPERMONT 75 102 72 99 71 / 20 0 10 0 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33/23
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
636 PM CDT SUN AUG 24 2014
.AVIATION...
CURRENT RADAR TRENDS SUGGEST THAT KLBB AND KCDS MAY ESCAPE ANY
-TSRA IN THE NEXT HOUR OR SO...BUT THERE IS STILL AN OUTSIDE
CHANCE. ALSO...SOME GUSTY OUTFLOW WINDS ARE STILL POSSIBLE.
OTHERWISE...VFR CONDITIONS WITH SRLY SURFACE WINDS EXPECTED
THROUGH MID-AFTERNOON MONDAY.
&&
.PREV DISCUSSION... /ISSUED 343 PM CDT SUN AUG 24 2014/
SHORT TERM...
DESPITE OF A WESTWARD EXPANSION OF WEAK RIDGING ALOFT AND VERY
LITTLE IF ANY SURFACE FEATURES...AN ADEQUATE BOOST IN THETA-E EARLIER
TODAY SUPPLIED MUCH OF THE AREA WITH DEEPER MOISTURE NECESSARY FOR
SOME DIURNALLY DRIVEN TSTORMS. NON-HIGH RES MODELS HAVE LARGELY
MISSED THE BOAT SO FAR TODAY WITH THE EXPERIMENTAL MODELS PLAYING
THE ROLE OF THE DARK HORSE. RAP DATA SHOW THE RICHEST PWATS OF 1.3
INCHES CONFINED EAST OF A BROWNFIELD TO SILVERTON LINE WITH
GENERALLY ONE INCH OR LESS FARTHER WEST. ENVIRONMENT IN THE RICHER
PWATS IS CHARACTERIZED BY SBCAPES OF 1200-2500 J/KG WITH WEAK SHEAR.
THIS THEME WILL PERSIST THROUGH MID-EVENING AT WHICH POINT TSTORMS
WILL DWINDLE...BUT UNTIL THEN WE EXPECT ADDITIONAL STRONG TO PERHAPS
BRIEFLY SEVERE PULSE MODES WITH MICROBURSTS THE PRIMARY HAZARD.
BY MONDAY MORNING...DEEPER MONSOONAL MOISTURE WILL BE TUGGED NORTH
INTO NEW MEXICO AROUND THE ZONAL RIDGE AXIS STILL POISED FIRMLY OVER
THE SOUTH PLAINS. HEIGHT FIELDS ON THE WESTERN PERIPHERY OF THIS
RIDGE ARE NOT SHOWN TO BUILD ANY...SO THE OPPORTUNITY WILL EXIST FOR
ANOTHER ROUND OF SOLAR-POWERED TSTORMS MAINLY NEAR THE NM STATE LINE
WHERE OCCASIONAL DISTURBANCES ARE PROGGED TO LIFT NORTH FROM
CHIHUAHUA. OTHERWISE...WE CONTINUE TO SIDE WITH THE WARMER SPECTRUM
OF MOS GUIDANCE FOR BOTH LOWS AND HIGHS GIVEN THE RECENT OBSERVED
TRENDS.
LONG TERM...
COOLER WEATHER IS ON THE WAY AS WELL AS A SHOT FOR RAIN. BUT BEFORE
WE GET THERE...WARM AND DRY WEATHER WILL CONTINUE TO DOMINATE US AS
HIGH PRESSURE TO OUR EAST EXTENDS OVER THE REGION. OUR NORTHWESTERN
ZONES WILL HAVE A BIT OF A REPRIEVE MONDAY NIGHT AS A WEAKNESS
PROPAGATES AROUND THE WESTERN EDGE OF THE RIDGE. THE WEAKNESS MAKES
USE OF A SURFACE TROF LOCATED OVER THE SOUTHWESTERN TX PANHANDLE AND
FIRES SCATTERED CONVECTION IN THAT REGION. CHANCES ARE ONLY SLIGHT
AS THE AVAILABLE MONSOONAL MOISTURE ONLY COVERS A VERY SMALL AREA
WHICH COINCIDES WITH THE SURFACE TROF. BY TUESDAY AND INTO
WEDNESDAY...THE RIDGE TO OUR EAST BUILDS FURTHER WEST INHIBITING
CHANCES FOR ANY RAIN...HOWEVER A LOW AWAITS US OVER THE GREAT BASIN
AND IS READY TO MOVE IN AND DEFEAT THE EVIL RIDGE. WITH THE
EXCEPTION OF THE GFS...MODELS HAVE BEEN IN DECENT AGREEMENT WITH
HANDLING OF THE LOW THE PAST SEVERAL RUNS. THE 12Z RUN YIELDED THE
GFS SLOWING THE EASTWARD PROGRESSION OF THE LOW AND IS MORE IN LINE
WITH THE OTHER MODELS. THE LOW WILL INITIALLY START OFF CLOSED AS IT
MOVES ACROSS THE ROCKIES INTO THE CENTRAL PLAINS DURING WHICH TIME
IT WILL SLOWLY BECOME AN OPEN WAVE. BY LATE WEDNESDAY A COLD FRONT
SHOULD BE KNOCKING ON OUR DOOR. THE TIMING OF THE FRONT IS SOMEWHAT
IN QUESTION WITH TIMINGS RANGING FROM EARLY TO LATE THURSDAY...WITH
THURSDAY MORNING BEING THE TIMING CHOICE FOR THE TIME BEING. RAIN
CHANCES WILL EXIST ALONG THE FRONT...ESPECIALLY AS THE UPPER LEVEL
LOW PUSHES INTO THE REGION. PWATS OVER 1.3 INCHES WILL BE MORE THAN
ENOUGH TO AID IN MODERATE RAINFALL AMOUNTS. RAIN CHANCES WILL BE
HIGHEST THURSDAY NIGHT INTO EARLY FRIDAY AS A JET MAX PUSHES IN FROM
THE WEST ON THE SOUTHEAST SIDE OF THE LOW. AS OF NOW THE JET MAX IS
GREATEST OVER OUR SOUTHEASTERN ZONES. THIS COMBINED WITH A DIFFLUENT
UPPER PATTERN SHOULD BE MORE THAN EFFICIENT IN DEVELOPING PRECIP.
THE LOW WILL HAVE AN EXTENDED VISIT AND REMAIN OVERHEAD THROUGH LATE
SUNDAY BEFORE ZONAL FLOW TAKES OVER. TEMPERATURES WILL BE RELATIVELY
COOL IN THE SENSE OF TEMPS WILL BE AROUND SEASONAL AVERAGES BUT
COOLER THAN THEY WILL BE EARLIER THIS WEEK. DEPENDING ON THE
STRENGTH OF THE FRONT...SOME AREAS SUCH AS THE TEXAS PANHANDLE MAY
SEE BELOW AVERAGE TEMPS AS COOL AIR OVER MT INTO CA WILL BE PUSHED
SOUTHWARD. AS OF THIS AFTERNOON...PARTS OF INTERIOR MT HAVE FAILED
TO REACH INTO THE 50S. AS OF NOW THE COOLEST AIR WITH THE FRONT
LATER THIS WEEK SHOULD STAY TO OUR NORTH WITH THE COOL SIDE OF THE
FORECAST BEING IN THE UPPER 50S.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 65 92 63 90 62 / 10 20 20 10 10
TULIA 69 95 65 93 64 / 10 10 20 10 10
PLAINVIEW 65 95 64 92 64 / 10 10 10 10 10
LEVELLAND 67 94 65 91 64 / 10 10 20 10 10
LUBBOCK 72 96 68 94 68 / 10 10 10 10 10
DENVER CITY 67 95 65 92 65 / 10 10 10 10 10
BROWNFIELD 66 96 66 93 66 / 10 10 10 10 10
CHILDRESS 73 101 72 98 72 / 20 10 10 10 10
SPUR 70 100 68 96 68 / 20 0 10 0 10
ASPERMONT 75 102 72 99 71 / 10 0 10 0 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1051 PM CDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 913 PM CDT SUN AUG 24 2014
THE FIRST WAVE OF CONVECTION HAS DEVELOPED AND TRACKED TO THE
NORTHEAST ACROSS EASTERN MINNESOTA AND NORTHWEST WISCONSIN WITH
JUST A FEW SHOWERS LEFT OVER GOING DOWN INTO CENTRAL IOWA. THE
FOCUS NOW SHIFTS TO THE SECOND WAVE OF CONVECTION THAT IS EXPECTED
TO DEVELOP OVERNIGHT AS A WEAK MID LEVEL SHORT WAVE TROUGH LIFTS
NORTHWARD FROM THE CENTRAL PLAINS. THIS CONVECTION IS EXPECTED TO
DEVELOP OUT AHEAD OF A EASTWARD PROPAGATING SURFACE COLD FRONT
THAT CURRENTLY EXTENDS FROM THE TWIN CITIES DOWN THE I-35 CORRIDOR
AND THEN BACK SOUTHWEST TOWARD OMAHA. THIS AIR MASS AHEAD OF THE
FRONT WILL REMAIN VERY UNSTABLE THROUGH THE OVERNIGHT HOURS WITH
25.00Z RAP SOUNDINGS SHOWING ABOUT 2000-4000 J/KG OF ELEVATED
INSTABILITY OUT IN THE WARM SECTOR. HOWEVER...THE WIND FIELD FROM
THE TOP OF THE LOW LEVEL INVERSION ON UP IS ALL UNIDIRECTIONAL AND
AT THE SAME SPEED...SO THERE IS ALMOST NO WIND SHEAR TO WORK WITH.
THE PAST FEW RUNS OF THE HRRR HAVE BEEN FAIRLY CONSISTENT WITH
SHOWING CONVECTION INITIATING OVER CENTRAL IOWA OVER THE NEXT FEW
HOURS AND THEN DEVELOPING NORTHWARD ALONG THE FRONT INTO WESTERN
WISCONSIN. GIVEN THE HIGH INSTABILITY...LOW SHEAR
ENVIRONMENT...CAN NOT RULE OUT A FEW ISOLATED STORMS THAT COULD
PRODUCE SOME MARGINALLY SEVERE HAIL ALONG WITH BRIEF HEAVY
DOWNPOURS...BUT IT SHOULD NOT BE A WIDESPREAD EVENT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 304 PM CDT SUN AUG 24 2014
THE MAIN CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS AFTERNOON SHOWS AN AREA OF LOW PRESSURE OVER
NORTH DAKOTA WITH A COLD FRONT TRAILING SOUTH THROUGH WESTERN
MINNESOTA INTO NEBRASKA. WATER VAPOR IMAGERY SHOWS A WOUND UP
UPPER LEVEL LOW OVER EASTERN MONTANA THAT WAS LIFTING TO THE
NORTHEAST.
THE 24.12Z MODELS ARE ALL IN REASONABLY GOOD AGREEMENT WITH THE
HANDLING OF THE UPPER LEVEL SYSTEM. IT WILL CONTINUE TO MOVE
NORTHEAST REACHING WESTERN ONTARIO BY MONDAY EVENING. THE MAIN
SHORT WAVE TROUGH WITH THIS SYSTEM IS VERY NEAR THE UPPER LEVEL
LOW AND IS EXPECTED TO REMAIN THAT WAY. THIS TAKES THE PV
ADVECTION IN THE 500-300 MB LAYER FROM EASTERN NORTH DAKOTA ACROSS
NORTHWEST MINNESOTA INTO ONTARIO. THIS WILL TAKE THE BULK OF THE
UPPER LEVEL FORCING WELL NORTH OF THE REGION BUT SOME UPPER LEVEL
DIVERGENCE SHOULD SPREAD ACROSS THE AREA TONIGHT AS THE RIGHT
ENTRANCE REGION OF THE UPPER LEVEL JET MOVES OVER. AS THE FRONT
MOVES IN TONIGHT...SOME WEAK FRONTOGENESIS SHOULD OCCUR IN THE
850-500 MB LAYER. GOOD LOW LEVEL WARM AIR ADVECTION AHEAD OF THE
FRONT WILL HELP TO GENERATE 4 TO 6 UBAR/S OF UP GLIDE ON THE 310K
ISENTROPIC SURFACE WITH THE MOISTURE TRANSPORT ON THIS SURFACE
EXPECTED TO BE INTO THE AREA FROM LATE EVENING THROUGH THE
OVERNIGHT HOURS. THE 24.12Z SOUNDING FROM KMPX SHOWS A STRONG CAP
IS IN PLACE BETWEEN 850 AND 700 MB AND THE CONCERN BECOMES WHETHER
THE FORCING WILL BE STRONG ENOUGH TO BREAK THE CAP. THE 24.12Z NAM
BUFKIT SOUNDINGS SUGGEST THAT THE CAP MAY WEAKEN BUT NOT TOTALLY
BREAK AND THIS IS REFLECTED IN THE MODEL ONLY PRODUCING SOME
SCATTERED ACTIVITY ALONG THE FRONT AS IT COMES THROUGH. THE
24.12Z GFS AND ECMWF SHOW MUCH MORE QPF ALONG THE FRONT SUGGESTING
THE CAP WILL BREAK. THE SHORT TERM MESO-MODELS ARE ABOUT AS
EQUALLY SPLIT. THE 24.12Z HI-RES ARW LOOKS TO HOLD THE CAP IN
PLACE WITH ALMOST NO ACTIVITY OVER THE AREA...WHILE THE HI-RES NMM
IS CLOSER TO THE NAM WITH JUST SOME SCATTERED ACTIVITY. THE 24.12Z
SPC WRF LOOKS TO DISSIPATE THE CAP AS EARLY AS LATE THIS AFTERNOON
WITH LOTS OF CONVECTION DEVELOPING ACROSS MINNESOTA AND MOVING
ACROSS THE AREA IN THE NIGHT. OUTPUT FROM THE 24.12Z HOP WRF IS
ALSO SPLIT WITH A COUPLE OF MEMBERS DEVELOPING LOTS OF CONVECTION
AND THE OTHER TWO STAYING WITH JUST SCATTERED ACTIVITY. IF THE CAP
WOULD BREAK...THE BEST CHANCE FOR THIS TO OCCUR WOULD BE ACROSS
THE NORTHERN SECTIONS OF THE FORECAST AREA CLOSER TO THE DYNAMIC
FORCING AND WILL MAINTAIN THE LIKELY RAIN CHANCES ACROSS THAT AREA
WHILE TAPERING DOWN TO 30 TO 40 PERCENT CHANCE ACROSS THE SOUTH.
SOME THREAT OF SEVERE ACROSS THE NORTH AS WELL IF THE CAP CAN
BREAK. PLENTY OF INSTABILITY WILL REMAIN IN PLACE AHEAD OF THE
FRONT WITH THE NAM SHOWING 1000-1500 J/KG OF ML CAPE ALONG WITH 40
KNOTS OF 0-3KM SHEAR. DAMAGING WINDS AND HEAVY RAIN SHOULD BE THE
MAIN THREATS AS WARM CLOUD DEPTHS WILL REMAIN IN THE 3.5 TO 4 KM
RANGE AHEAD OF THE FRONT. MAY ALSO HAVE TO AWARE OF A SPIN UP
TORNADO THREAT AS A DIFFERENTIAL HEATING BOUNDARY IS IN PLACE ON
THE CLOUD EDGE. IF THIS BOUNDARY MAINTAINS ITSELF INTO THE
EVENING...THE NAM INDICATES THE 0-1KM SHEAR WILL INCREASE TO
AROUND 25 KNOTS.
THE FRONT SHOULD THEN PASS THROUGH THE AREA MONDAY WITH THE
POSSIBILITY OF SOME SCATTERED ACTIVITY ALONG IT. NOT MUCH FORCING
ALONG THE FRONT BUT COULD SEE A DIURNAL INCREASE IN THE ACTIVITY
DURING THE AFTERNOON WHEN THE ML CAPE SHOULD AGAIN BE IN THE
2000-3000 J/KG RANGE.
THE MODELS THEN HAVE REALLY TRENDED TOWARD PUSHING THIS FRONT
FARTHER SOUTH FROM MONDAY NIGHT INTO TUESDAY NIGHT AS THE HIGH
PRESSURE BUILDING IN BEHIND IT IS MUCH STRONGER. MODELS CONTINUE
TO SHOW A SHORT WAVE TROUGH MOVING ALONG THE UPPER LEVEL RIDGE
AXIS AND INTERACTING WITH THE FRONT. IF THE FRONT DOES PUSH AS FAR
SOUTH AS THE MODELS ARE CURRENTLY INDICATING...THIS WOULD PLACE
THE HIGHEST RAIN CHANCES SOUTH OF THE IOWA/MINNESOTA BORDER. WILL
MAINTAIN SOME 50 TO 60 PERCENT CHANCES FROM MONDAY NIGHT INTO
TUESDAY NIGHT...BUT LIMIT THEM TO THE SOUTHERN SECTIONS.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 304 PM CDT SUN AUG 24 2014
THE FRONT IS EXPECTED TO STILL NOT BE TOO FAR SOUTH OF THE AREA
BY THE MIDDLE OF THE WEEK. THE 24.12Z ECMWF AND GFS IN DECENT
AGREEMENT OF BRINGING ANOTHER SHORT WAVE TROUGH ACROSS THE TOP OF
THE RIDGE AXIS WITH A SURFACE LOW MOVING ALONG THE FRONT. BASED ON
THIS...WILL HAVE UP TO 50 PERCENT CHANCES ACROSS THE SOUTH FROM
WEDNESDAY INTO THURSDAY NIGHT. THE RAIN CHANCES SHOULD THEN
DIMINISH TO CLOSE OUT THE WEEK INTO THE WEEKEND AS HIGH PRESSURE
BUILDS IN BEHIND THE MID WEEK SYSTEM.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1051 PM CDT SUN AUG 24 2014
SHOWERS AND THUNDERSTORMS ARE LIKELY OVERNIGHT INTO MONDAY MORNING
AHEAD OF A COLD FRONT THAT CURRENTLY IS IN EASTERN
MINNESOTA/CENTRAL IOWA. A HIGHLY UNSTABLE AIR MASS AHEAD OF THIS
FRONT SHOULD HELP TO KEEP THIS LINE OF DEVELOPING THUNDERSTORMS
GOING AS THEY TRACK TO THE EAST OVERNIGHT WITH VISIBILITY LIKELY
DROPPING DOWN TO IFR FOR A BRIEF PERIOD. WINDS WILL THEN SHIFT
AROUND TO THE WEST THIS AFTERNOON ON INTO MONDAY NIGHT AS THE
FRONT SLOWLY SHIFTS TO THE EAST.
&&
.HYDROLOGY...
ISSUED AT 304 PM CDT SUN AUG 24 2014
HEAVY RAIN WILL BE A THREAT WITH ANY STORMS THAT DEVELOP TONIGHT.
WARM CLOUD DEPTHS WILL BE IN THE 3.5 TO 4 KM RANGE WITH
PRECIPITABLE WATERS APPROACHING TWO INCHES. THE CONCERN FOR HEAVY
RAIN AND POSSIBLE FLOODING WITH THE STALLED FRONT FOR THE EARLY
PART OF THE WEEK ARE DIMINISHING WITH THE FRONT EXPECTED TO PUSH
FARTHER SOUTH. THE HIGHEST AXIS OF PRECIPITABLE WATERS SHOULD LAY
UP SOUTH OF THE FRONT ACROSS SOUTHERN IOWA/NORTHERN MISSOURI INTO
ILLINOIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...04
LONG TERM...04
AVIATION...HALBACH
HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
913 PM CDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 913 PM CDT SUN AUG 24 2014
THE FIRST WAVE OF CONVECTION HAS DEVELOPED AND TRACKED TO THE
NORTHEAST ACROSS EASTERN MINNESOTA AND NORTHWEST WISCONSIN WITH
JUST A FEW SHOWERS LEFT OVER GOING DOWN INTO CENTRAL IOWA. THE
FOCUS NOW SHIFTS TO THE SECOND WAVE OF CONVECTION THAT IS EXPECTED
TO DEVELOP OVERNIGHT AS A WEAK MID LEVEL SHORT WAVE TROUGH LIFTS
NORTHWARD FROM THE CENTRAL PLAINS. THIS CONVECTION IS EXPECTED TO
DEVELOP OUT AHEAD OF A EASTWARD PROPAGATING SURFACE COLD FRONT
THAT CURRENTLY EXTENDS FROM THE TWIN CITIES DOWN THE I-35 CORRIDOR
AND THEN BACK SOUTHWEST TOWARD OMAHA. THIS AIR MASS AHEAD OF THE
FRONT WILL REMAIN VERY UNSTABLE THROUGH THE OVERNIGHT HOURS WITH
25.00Z RAP SOUNDINGS SHOWING ABOUT 2000-4000 J/KG OF ELEVATED
INSTABILITY OUT IN THE WARM SECTOR. HOWEVER...THE WIND FIELD FROM
THE TOP OF THE LOW LEVEL INVERSION ON UP IS ALL UNIDIRECTIONAL AND
AT THE SAME SPEED...SO THERE IS ALMOST NO WIND SHEAR TO WORK WITH.
THE PAST FEW RUNS OF THE HRRR HAVE BEEN FAIRLY CONSISTENT WITH
SHOWING CONVECTION INITIATING OVER CENTRAL IOWA OVER THE NEXT FEW
HOURS AND THEN DEVELOPING NORTHWARD ALONG THE FRONT INTO WESTERN
WISCONSIN. GIVEN THE HIGH INSTABILITY...LOW SHEAR
ENVIRONMENT...CAN NOT RULE OUT A FEW ISOLATED STORMS THAT COULD
PRODUCE SOME MARGINALLY SEVERE HAIL ALONG WITH BRIEF HEAVY
DOWNPOURS...BUT IT SHOULD NOT BE A WIDESPREAD EVENT.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 304 PM CDT SUN AUG 24 2014
THE MAIN CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS AFTERNOON SHOWS AN AREA OF LOW PRESSURE OVER
NORTH DAKOTA WITH A COLD FRONT TRAILING SOUTH THROUGH WESTERN
MINNESOTA INTO NEBRASKA. WATER VAPOR IMAGERY SHOWS A WOUND UP
UPPER LEVEL LOW OVER EASTERN MONTANA THAT WAS LIFTING TO THE
NORTHEAST.
THE 24.12Z MODELS ARE ALL IN REASONABLY GOOD AGREEMENT WITH THE
HANDLING OF THE UPPER LEVEL SYSTEM. IT WILL CONTINUE TO MOVE
NORTHEAST REACHING WESTERN ONTARIO BY MONDAY EVENING. THE MAIN
SHORT WAVE TROUGH WITH THIS SYSTEM IS VERY NEAR THE UPPER LEVEL
LOW AND IS EXPECTED TO REMAIN THAT WAY. THIS TAKES THE PV
ADVECTION IN THE 500-300 MB LAYER FROM EASTERN NORTH DAKOTA ACROSS
NORTHWEST MINNESOTA INTO ONTARIO. THIS WILL TAKE THE BULK OF THE
UPPER LEVEL FORCING WELL NORTH OF THE REGION BUT SOME UPPER LEVEL
DIVERGENCE SHOULD SPREAD ACROSS THE AREA TONIGHT AS THE RIGHT
ENTRANCE REGION OF THE UPPER LEVEL JET MOVES OVER. AS THE FRONT
MOVES IN TONIGHT...SOME WEAK FRONTOGENESIS SHOULD OCCUR IN THE
850-500 MB LAYER. GOOD LOW LEVEL WARM AIR ADVECTION AHEAD OF THE
FRONT WILL HELP TO GENERATE 4 TO 6 UBAR/S OF UP GLIDE ON THE 310K
ISENTROPIC SURFACE WITH THE MOISTURE TRANSPORT ON THIS SURFACE
EXPECTED TO BE INTO THE AREA FROM LATE EVENING THROUGH THE
OVERNIGHT HOURS. THE 24.12Z SOUNDING FROM KMPX SHOWS A STRONG CAP
IS IN PLACE BETWEEN 850 AND 700 MB AND THE CONCERN BECOMES WHETHER
THE FORCING WILL BE STRONG ENOUGH TO BREAK THE CAP. THE 24.12Z NAM
BUFKIT SOUNDINGS SUGGEST THAT THE CAP MAY WEAKEN BUT NOT TOTALLY
BREAK AND THIS IS REFLECTED IN THE MODEL ONLY PRODUCING SOME
SCATTERED ACTIVITY ALONG THE FRONT AS IT COMES THROUGH. THE
24.12Z GFS AND ECMWF SHOW MUCH MORE QPF ALONG THE FRONT SUGGESTING
THE CAP WILL BREAK. THE SHORT TERM MESO-MODELS ARE ABOUT AS
EQUALLY SPLIT. THE 24.12Z HI-RES ARW LOOKS TO HOLD THE CAP IN
PLACE WITH ALMOST NO ACTIVITY OVER THE AREA...WHILE THE HI-RES NMM
IS CLOSER TO THE NAM WITH JUST SOME SCATTERED ACTIVITY. THE 24.12Z
SPC WRF LOOKS TO DISSIPATE THE CAP AS EARLY AS LATE THIS AFTERNOON
WITH LOTS OF CONVECTION DEVELOPING ACROSS MINNESOTA AND MOVING
ACROSS THE AREA IN THE NIGHT. OUTPUT FROM THE 24.12Z HOP WRF IS
ALSO SPLIT WITH A COUPLE OF MEMBERS DEVELOPING LOTS OF CONVECTION
AND THE OTHER TWO STAYING WITH JUST SCATTERED ACTIVITY. IF THE CAP
WOULD BREAK...THE BEST CHANCE FOR THIS TO OCCUR WOULD BE ACROSS
THE NORTHERN SECTIONS OF THE FORECAST AREA CLOSER TO THE DYNAMIC
FORCING AND WILL MAINTAIN THE LIKELY RAIN CHANCES ACROSS THAT AREA
WHILE TAPERING DOWN TO 30 TO 40 PERCENT CHANCE ACROSS THE SOUTH.
SOME THREAT OF SEVERE ACROSS THE NORTH AS WELL IF THE CAP CAN
BREAK. PLENTY OF INSTABILITY WILL REMAIN IN PLACE AHEAD OF THE
FRONT WITH THE NAM SHOWING 1000-1500 J/KG OF ML CAPE ALONG WITH 40
KNOTS OF 0-3KM SHEAR. DAMAGING WINDS AND HEAVY RAIN SHOULD BE THE
MAIN THREATS AS WARM CLOUD DEPTHS WILL REMAIN IN THE 3.5 TO 4 KM
RANGE AHEAD OF THE FRONT. MAY ALSO HAVE TO AWARE OF A SPIN UP
TORNADO THREAT AS A DIFFERENTIAL HEATING BOUNDARY IS IN PLACE ON
THE CLOUD EDGE. IF THIS BOUNDARY MAINTAINS ITSELF INTO THE
EVENING...THE NAM INDICATES THE 0-1KM SHEAR WILL INCREASE TO
AROUND 25 KNOTS.
THE FRONT SHOULD THEN PASS THROUGH THE AREA MONDAY WITH THE
POSSIBILITY OF SOME SCATTERED ACTIVITY ALONG IT. NOT MUCH FORCING
ALONG THE FRONT BUT COULD SEE A DIURNAL INCREASE IN THE ACTIVITY
DURING THE AFTERNOON WHEN THE ML CAPE SHOULD AGAIN BE IN THE
2000-3000 J/KG RANGE.
THE MODELS THEN HAVE REALLY TRENDED TOWARD PUSHING THIS FRONT
FARTHER SOUTH FROM MONDAY NIGHT INTO TUESDAY NIGHT AS THE HIGH
PRESSURE BUILDING IN BEHIND IT IS MUCH STRONGER. MODELS CONTINUE
TO SHOW A SHORT WAVE TROUGH MOVING ALONG THE UPPER LEVEL RIDGE
AXIS AND INTERACTING WITH THE FRONT. IF THE FRONT DOES PUSH AS FAR
SOUTH AS THE MODELS ARE CURRENTLY INDICATING...THIS WOULD PLACE
THE HIGHEST RAIN CHANCES SOUTH OF THE IOWA/MINNESOTA BORDER. WILL
MAINTAIN SOME 50 TO 60 PERCENT CHANCES FROM MONDAY NIGHT INTO
TUESDAY NIGHT...BUT LIMIT THEM TO THE SOUTHERN SECTIONS.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 304 PM CDT SUN AUG 24 2014
THE FRONT IS EXPECTED TO STILL NOT BE TOO FAR SOUTH OF THE AREA
BY THE MIDDLE OF THE WEEK. THE 24.12Z ECMWF AND GFS IN DECENT
AGREEMENT OF BRINGING ANOTHER SHORT WAVE TROUGH ACROSS THE TOP OF
THE RIDGE AXIS WITH A SURFACE LOW MOVING ALONG THE FRONT. BASED ON
THIS...WILL HAVE UP TO 50 PERCENT CHANCES ACROSS THE SOUTH FROM
WEDNESDAY INTO THURSDAY NIGHT. THE RAIN CHANCES SHOULD THEN
DIMINISH TO CLOSE OUT THE WEEK INTO THE WEEKEND AS HIGH PRESSURE
BUILDS IN BEHIND THE MID WEEK SYSTEM.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 653 PM CDT SUN AUG 24 2014
THE MAIN FOCUS AT THE TAF SITES IS WITH THE CONVECTIVE TRENDS
TONIGHT AS A COLD FRONT MOVES THROUGH THE REGION. A BATCH OF
SHOWERS/STORMS HAS DEVELOPED IN NC IA/SC MN AND HAS BEEN TRACKING
TO THE NORTHEAST AND WILL BE CLOSE TO RST. AFTER A BRIEF BREAK
THIS EVENING...A SECOND ROUND OF CONVECTION IS POSSIBLE OVERNIGHT
AND SHOULD BE A BIT MORE WIDESPREAD. THE MAIN PERIOD IT IS
EXPECTED TO COME THROUGH RST WOULD BE BETWEEN 5-9Z AND LSE BETWEEN
8-11Z. SOME DROPS TO MVFR/IFR VISIBILITY WILL BE POSSIBLE IF THE
SHOWERS/STORMS DO BECOME WIDESPREAD. WINDS WILL COME AROUND TO THE
WEST TOMORROW AFTERNOON AS THE COLD FRONT PASSES THROUGH AND
BRINGS AN END TO THE CHANCES FOR PRECIPITATION.
&&
.HYDROLOGY...
ISSUED AT 304 PM CDT SUN AUG 24 2014
HEAVY RAIN WILL BE A THREAT WITH ANY STORMS THAT DEVELOP TONIGHT.
WARM CLOUD DEPTHS WILL BE IN THE 3.5 TO 4 KM RANGE WITH
PRECIPITABLE WATERS APPROACHING TWO INCHES. THE CONCERN FOR HEAVY
RAIN AND POSSIBLE FLOODING WITH THE STALLED FRONT FOR THE EARLY
PART OF THE WEEK ARE DIMINISHING WITH THE FRONT EXPECTED TO PUSH
FARTHER SOUTH. THE HIGHEST AXIS OF PRECIPITABLE WATERS SHOULD LAY
UP SOUTH OF THE FRONT ACROSS SOUTHERN IOWA/NORTHERN MISSOURI INTO
ILLINOIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...04
LONG TERM...04
AVIATION...HALBACH
HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
702 PM CDT SUN AUG 24 2014
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 243 PM CDT SUN AUG 24 2014
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW UPPER LEVEL
LOW PRESSURE OVER EASTERN MONTANA AND A DOUBLE BARRELED SURFACE LOW
OVER NORTH DAKOTA. A WARM FRONT EXTENDS FROM THIS SURFACE LOW OVER
SOUTHWEST WISCONSIN...WHICH MARKS THE TRANSITION FROM MOSTLY CLOUDY
SKIES TO CLEAR CONDITIONS. A COLD FRONT EXTENDS SOUTHWARD OVER THE
CENTRAL PLAINS AND IS LARGELY INACTIVE AT THIS HOUR THOUGH THAT
MIGHT BE CHANGING OVER CENTRAL MINNESOTA WHERE ML CAPES HAVE
EXCEEDED 2000 J/KG. A FEW OTHER ELEVATED STORMS CONTINUE TO DEVELOP
OVER NORTHWEST WISCONSIN WITHIN THE TAIL END OF A VORT MAX. WILL
ADD A CHANCE TO N-C WISCONSIN BETWEEN 21Z AND 00Z. AS THE UPPER LOW
AND COLD FRONT MOVE EAST...THUNDERSTORM AND SEVERE WEATHER CHANCES
ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE LARGE UPPER LOW WILL MOVE ACROSS NORTH DAKOTA INTO THE
LAKE WINNIPEG REGION. MID-LEVEL HEIGHT FALLS FROM THE SYSTEM WILL
MOVE INTO THE WESTERN GREAT LAKES...WHICH WILL HELP PUSH A WEAK COLD
FRONT INTO WESTERN WISCONSIN AFTER MIDNIGHT. CONVERGENCE ALONG THE
FRONT IS RELATIVELY WEAK...BUT ELEVATED INSTABILITY APPROX 1000-1500
J/KG (ROUGH ESTIMATE) WILL MOVE INTO CENTRAL AND NORTH-CENTRAL
WISCONSIN AFTER MIDNIGHT. BECAUSE OF THE WEAK FORCING...KEPT
CHANCES OF PRECIP IN THE SCATTERED RANGE. THE MAGNITUDE OF CAPE AND
WIND SHEAR AROUND 30 KTS WOULD SUPPORT A CHANCE OF STRONG STORMS
THAT COULD PRODUCE NEAR SEVERE HAIL AND WIND GUSTS. WILL LEAVE A
MENTION OF THIS POSSIBILITY IN THE HWO. THE MESO MODELS CONTINUE TO
SHOW CONVECTION DEVELOPING OVER CENTRAL MINNESOTA LATER THIS
AFTERNOON BEFORE TRACKING THE STORMS INTO NORTH-CENTRAL WISCONSIN
AFTER 06Z. THIS STILL SEEMS POSSIBLE BASED ON THE DESTABILIZATION
TAKING PLACE OVER CENTRAL MINNESOTA. THE STORMS SHOULD WEAKEN AS
THEY MOVE EAST LATE TONIGHT DUE TO DIMINISHING INSTABILITY.
OTHERWISE...LOOK FOR A MUGGY EVENING WITH LOWS DROPPING INTO THE
MIDDLE AND UPPER 60S.
MONDAY...THE FRONT WILL MAKE LITTLE PROGRESS TO THE EAST AND INTO
NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. SPOTTY SHOWERS AND
STORMS WILL BE POSSIBLE AHEAD OF THE FRONT DURING THE MORNING ACROSS
MUCH OF THE AREA. ASSUMING COVERAGE IS NOT MORE THAN
ADVERTISED...LOW LEVEL SOUTHWEST WINDS WILL PUSH TEMPS INTO THE
UPPER 80S OR LOWER 90S OVER THE EASTERN FORECAST AREA. COMBINED
WITH DEWPOINTS AROUND 70 DEGREES...ML CAPES ARE PROJECTED TO REACH
2K-3K J/KG WITH BULK SHEARS AROUND 30 KTS. CONVERGENCE ALONG THE
FRONT WILL REMAIN WEAK BUT CANNOT RULE OUT ISOLATED OR SCATTERED
STRONG TO SEVERE STORMS OVER THE EAST DURING THE AFTERNOON WITH THAN
KIND OF INSTABILITY AND SHEAR. DRIER MID-LEVEL AIR WILL WORK INTO
CENTRAL AND NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON...WHICH
WILL MAKE IT HARDER FOR STORMS TO INITIATE. THE COMBINATION OF HEAT
AND HUMIDITY WILL PUSH HEAT INDICES INTO THE MIDDLE 90S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 243 PM CDT SUN AUG 24 2014
MODELS CONTINUE TO INDICATE A RATHER AMPLIFIED MEAN FLOW PATTERN ACROSS
THE CONUS WITH AN UPPER TROF CURRENTLY OVER THE INTER MOUNTAIN
WEST AND SIG RIDGE OVER THE EASTERN LAKES. THE MOVEMENT OF UPPER
LOW OUT OF TROF INTO THE WESTERN LAKES EARLY IN THE PERIOD WILL BE
THE PRIMARY WEATHER FEATURE TO IMPACT OUR WEATHER. BY LATE THIS
WEEK...MODELS CONTINUE TO SHOW LINGERING PIECE OF TROF MEANDERING
INTO THE CENTRAL U.S. THE MOVEMENT OF THIS FEATURE CONTINUES TO
SLOW AS IT REMAINS CUT OFF FROM MAIN BAND OF WESTERLIES EXPECTED
TO LIE OVER SOUTHERN CANADA. FORECAST CONFIDENCE LOW THU NIGHT
ONWARD.
TREND IN SHORTER RANGE IS TO CONTINUE TO SLOW PASSAGE OF COLD
FRONT MONDAY WITH FRONT STILL BISECTING CWA AT 00Z TUE. HAVE
CONTINUE SCATTERED/CHANCE POPS MAINLY SOUTH AND EAST GIVEN
AVAILABLE INSTABILITY. LITTLE DYNAMICS BESIDES FRONT TO SUPPORT
GOING ANY HIGHER WITH POPS.
CONSISTENCY SEEN IN MODELS TO PUSH FRONT AND PCPN MAINLY SOUTH OF
CWA AS HIGH PRESSURE AND DRIER AIR MASS MOVES IN OVER NORTHERN WI
TUE INTO THU. CONCERN THIS PERIOD ON TEMPS. DRIER AIR...SUN AND
LOW LEVEL TEMPS AT OR SLIGHTLY BELOW NORMAL SHOULD SUPPORT TEMPS IN
THE LOWER TO MIDDLE 70S. WILL HAVE EAST FLOW OFF LAKE THOUGH LAKE
SURFACE TEMPS NOW IN MID TO UPPER 60S SO HAVE CONFINED COOLING TO
CLOSER TO THE COAST. HAVE BUMPED MAX TEMPS UP A BIT MID WEEK.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 702 PM CDT SUN AUG 24 2014
MVFR CEILINGS IN NORTHCENTRAL WISCONSIN WILL DIMINISH
THIS EVENING AND MUCH OF THE AREA SHOULD BE VFR FOR PART OF THE
NIGHT UNTIL A BROKEN AREA OF SHOWERS AND THUNDERSTORMS ARRIVES
LATE TONIGHT FROM THE WEST. THE ACTIVITY WILL PROBABLY ARRIVE IN
RHINELANDER AND WAUSAU BETWEEN 07 AND 09Z AND AT APPLETON...OSHKOSH
AND GREEN BAY BETWEEN 10Z AND 12Z IF IT HOLDS TOGETHER.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......RDM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
653 PM CDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 600 PM CDT SUN AUG 24 2014
MONITORING CONVECTIVE TRENDS ACROSS THE REGION...WITH A
PARTICULAR FOCUS ON SOUTHEAST MINNESOTA INTO THE EARLY EVENING
HOURS. THE 24.22Z RAP ANALYSIS SHOWS A VERY UNSTABLE AIR MASS IS
CENTERED ALONG THE MISSISSIPPI RIVER WITH UPWARDS OF 3000-5000
J/KG OF SURFACE BASED CAPE NOSING UP TOWARD THE TWIN CITIES.
HOWEVER...THIS AIR MASS APPEARS TO BE CAPPED OFF DUE TO THE LACK
OF A CUMULUS FIELD ACROSS SE MN/NE IA/W WI. ALSO...DEEP WIND SHEAR
IS ALSO VERY LACKING THIS FAR SOUTH...SO WHILE SOME CONVECTION HAS
INITIATED ACROSS NC IA/SC MN...IT HAS BEEN VERY PULSEY AND CAN NOT
MAINTAIN ITSELF FOR VERY LONG. FURTHER NORTH WHERE THERE IS DEEPER
WIND SHEAR AND BETTER CONVERGENCE IN THE SURFACE FEATURES...STORMS
ARE QUICKLY GOING SEVERE. WHILE THERE WILL BE ABOUT A 2-3 HOUR
PERIOD FROM NOW THROUGH 9 PM WHERE THIS CONVECTION WILL COME
THROUGH MOWER/DODGE/OLMSTED COUNTIES...EXPECTING THAT IT WILL STAY
UNORGANIZED AND NOT SEVERE. SOME OF THIS CONVECTION COULD MAKE IT
INTO ROCHESTER AROUND 7PM...BUT THE NORTHERN EDGE OF THE CAP
APPEARS TO BE AT OR JUST TO THE NORTH OF THE CITY...WHICH WOULD
HELP TO KEEP THEM DRY THIS EVENING. BEYOND THIS...THERE APPEARS TO
BE A SECOND WAVE OF CONVECTION POSSIBLE OVERNIGHT AS THE MAIN
TROUGH/SURFACE COLD FRONT APPROACH FROM THE WEST. INSTABILITY
REMAINS HIGH OVERNIGHT...BUT THE OVERALL SHEAR IS LACKING WHICH
SHOULD KEEP THIS CONVECTION UN-ORGANIZED AND MAINLY NOT SEVERE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 304 PM CDT SUN AUG 24 2014
THE MAIN CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS AFTERNOON SHOWS AN AREA OF LOW PRESSURE OVER
NORTH DAKOTA WITH A COLD FRONT TRAILING SOUTH THROUGH WESTERN
MINNESOTA INTO NEBRASKA. WATER VAPOR IMAGERY SHOWS A WOUND UP
UPPER LEVEL LOW OVER EASTERN MONTANA THAT WAS LIFTING TO THE
NORTHEAST.
THE 24.12Z MODELS ARE ALL IN REASONABLY GOOD AGREEMENT WITH THE
HANDLING OF THE UPPER LEVEL SYSTEM. IT WILL CONTINUE TO MOVE
NORTHEAST REACHING WESTERN ONTARIO BY MONDAY EVENING. THE MAIN
SHORT WAVE TROUGH WITH THIS SYSTEM IS VERY NEAR THE UPPER LEVEL
LOW AND IS EXPECTED TO REMAIN THAT WAY. THIS TAKES THE PV
ADVECTION IN THE 500-300 MB LAYER FROM EASTERN NORTH DAKOTA ACROSS
NORTHWEST MINNESOTA INTO ONTARIO. THIS WILL TAKE THE BULK OF THE
UPPER LEVEL FORCING WELL NORTH OF THE REGION BUT SOME UPPER LEVEL
DIVERGENCE SHOULD SPREAD ACROSS THE AREA TONIGHT AS THE RIGHT
ENTRANCE REGION OF THE UPPER LEVEL JET MOVES OVER. AS THE FRONT
MOVES IN TONIGHT...SOME WEAK FRONTOGENESIS SHOULD OCCUR IN THE
850-500 MB LAYER. GOOD LOW LEVEL WARM AIR ADVECTION AHEAD OF THE
FRONT WILL HELP TO GENERATE 4 TO 6 UBAR/S OF UP GLIDE ON THE 310K
ISENTROPIC SURFACE WITH THE MOISTURE TRANSPORT ON THIS SURFACE
EXPECTED TO BE INTO THE AREA FROM LATE EVENING THROUGH THE
OVERNIGHT HOURS. THE 24.12Z SOUNDING FROM KMPX SHOWS A STRONG CAP
IS IN PLACE BETWEEN 850 AND 700 MB AND THE CONCERN BECOMES WHETHER
THE FORCING WILL BE STRONG ENOUGH TO BREAK THE CAP. THE 24.12Z NAM
BUFKIT SOUNDINGS SUGGEST THAT THE CAP MAY WEAKEN BUT NOT TOTALLY
BREAK AND THIS IS REFLECTED IN THE MODEL ONLY PRODUCING SOME
SCATTERED ACTIVITY ALONG THE FRONT AS IT COMES THROUGH. THE
24.12Z GFS AND ECMWF SHOW MUCH MORE QPF ALONG THE FRONT SUGGESTING
THE CAP WILL BREAK. THE SHORT TERM MESO-MODELS ARE ABOUT AS
EQUALLY SPLIT. THE 24.12Z HI-RES ARW LOOKS TO HOLD THE CAP IN
PLACE WITH ALMOST NO ACTIVITY OVER THE AREA...WHILE THE HI-RES NMM
IS CLOSER TO THE NAM WITH JUST SOME SCATTERED ACTIVITY. THE 24.12Z
SPC WRF LOOKS TO DISSIPATE THE CAP AS EARLY AS LATE THIS AFTERNOON
WITH LOTS OF CONVECTION DEVELOPING ACROSS MINNESOTA AND MOVING
ACROSS THE AREA IN THE NIGHT. OUTPUT FROM THE 24.12Z HOP WRF IS
ALSO SPLIT WITH A COUPLE OF MEMBERS DEVELOPING LOTS OF CONVECTION
AND THE OTHER TWO STAYING WITH JUST SCATTERED ACTIVITY. IF THE CAP
WOULD BREAK...THE BEST CHANCE FOR THIS TO OCCUR WOULD BE ACROSS
THE NORTHERN SECTIONS OF THE FORECAST AREA CLOSER TO THE DYNAMIC
FORCING AND WILL MAINTAIN THE LIKELY RAIN CHANCES ACROSS THAT AREA
WHILE TAPERING DOWN TO 30 TO 40 PERCENT CHANCE ACROSS THE SOUTH.
SOME THREAT OF SEVERE ACROSS THE NORTH AS WELL IF THE CAP CAN
BREAK. PLENTY OF INSTABILITY WILL REMAIN IN PLACE AHEAD OF THE
FRONT WITH THE NAM SHOWING 1000-1500 J/KG OF ML CAPE ALONG WITH 40
KNOTS OF 0-3KM SHEAR. DAMAGING WINDS AND HEAVY RAIN SHOULD BE THE
MAIN THREATS AS WARM CLOUD DEPTHS WILL REMAIN IN THE 3.5 TO 4 KM
RANGE AHEAD OF THE FRONT. MAY ALSO HAVE TO AWARE OF A SPIN UP
TORNADO THREAT AS A DIFFERENTIAL HEATING BOUNDARY IS IN PLACE ON
THE CLOUD EDGE. IF THIS BOUNDARY MAINTAINS ITSELF INTO THE
EVENING...THE NAM INDICATES THE 0-1KM SHEAR WILL INCREASE TO
AROUND 25 KNOTS.
THE FRONT SHOULD THEN PASS THROUGH THE AREA MONDAY WITH THE
POSSIBILITY OF SOME SCATTERED ACTIVITY ALONG IT. NOT MUCH FORCING
ALONG THE FRONT BUT COULD SEE A DIURNAL INCREASE IN THE ACTIVITY
DURING THE AFTERNOON WHEN THE ML CAPE SHOULD AGAIN BE IN THE
2000-3000 J/KG RANGE.
THE MODELS THEN HAVE REALLY TRENDED TOWARD PUSHING THIS FRONT
FARTHER SOUTH FROM MONDAY NIGHT INTO TUESDAY NIGHT AS THE HIGH
PRESSURE BUILDING IN BEHIND IT IS MUCH STRONGER. MODELS CONTINUE
TO SHOW A SHORT WAVE TROUGH MOVING ALONG THE UPPER LEVEL RIDGE
AXIS AND INTERACTING WITH THE FRONT. IF THE FRONT DOES PUSH AS FAR
SOUTH AS THE MODELS ARE CURRENTLY INDICATING...THIS WOULD PLACE
THE HIGHEST RAIN CHANCES SOUTH OF THE IOWA/MINNESOTA BORDER. WILL
MAINTAIN SOME 50 TO 60 PERCENT CHANCES FROM MONDAY NIGHT INTO
TUESDAY NIGHT...BUT LIMIT THEM TO THE SOUTHERN SECTIONS.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 304 PM CDT SUN AUG 24 2014
THE FRONT IS EXPECTED TO STILL NOT BE TOO FAR SOUTH OF THE AREA
BY THE MIDDLE OF THE WEEK. THE 24.12Z ECMWF AND GFS IN DECENT
AGREEMENT OF BRINGING ANOTHER SHORT WAVE TROUGH ACROSS THE TOP OF
THE RIDGE AXIS WITH A SURFACE LOW MOVING ALONG THE FRONT. BASED ON
THIS...WILL HAVE UP TO 50 PERCENT CHANCES ACROSS THE SOUTH FROM
WEDNESDAY INTO THURSDAY NIGHT. THE RAIN CHANCES SHOULD THEN
DIMINISH TO CLOSE OUT THE WEEK INTO THE WEEKEND AS HIGH PRESSURE
BUILDS IN BEHIND THE MID WEEK SYSTEM.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 653 PM CDT SUN AUG 24 2014
THE MAIN FOCUS AT THE TAF SITES IS WITH THE CONVECTIVE TRENDS
TONIGHT AS A COLD FRONT MOVES THROUGH THE REGION. A BATCH OF
SHOWERS/STORMS HAS DEVELOPED IN NC IA/SC MN AND HAS BEEN TRACKING
TO THE NORTHEAST AND WILL BE CLOSE TO RST. AFTER A BRIEF BREAK
THIS EVENING...A SECOND ROUND OF CONVECTION IS POSSIBLE OVERNIGHT
AND SHOULD BE A BIT MORE WIDESPREAD. THE MAIN PERIOD IT IS
EXPECTED TO COME THROUGH RST WOULD BE BETWEEN 5-9Z AND LSE BETWEEN
8-11Z. SOME DROPS TO MVFR/IFR VISIBILITY WILL BE POSSIBLE IF THE
SHOWERS/STORMS DO BECOME WIDESPREAD. WINDS WILL COME AROUND TO THE
WEST TOMORROW AFTERNOON AS THE COLD FRONT PASSES THROUGH AND
BRINGS AN END TO THE CHANCES FOR PRECIPITATION.
&&
.HYDROLOGY...
ISSUED AT 304 PM CDT SUN AUG 24 2014
HEAVY RAIN WILL BE A THREAT WITH ANY STORMS THAT DEVELOP TONIGHT.
WARM CLOUD DEPTHS WILL BE IN THE 3.5 TO 4 KM RANGE WITH
PRECIPITABLE WATERS APPROACHING TWO INCHES. THE CONCERN FOR HEAVY
RAIN AND POSSIBLE FLOODING WITH THE STALLED FRONT FOR THE EARLY
PART OF THE WEEK ARE DIMINISHING WITH THE FRONT EXPECTED TO PUSH
FARTHER SOUTH. THE HIGHEST AXIS OF PRECIPITABLE WATERS SHOULD LAY
UP SOUTH OF THE FRONT ACROSS SOUTHERN IOWA/NORTHERN MISSOURI INTO
ILLINOIS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...04
LONG TERM...04
AVIATION...HALBACH
HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
309 PM CDT SAT AUG 23 2014
.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 309 PM CDT SAT AUG 23 2014
SHORT TERM MAIN CONCERN IS INCREASING HEAT SUNDAY.
WATER VAPOR/RAP 500MB ANALYSIS THIS AFTERNOON HAVE A MID-LEVEL
SHORTWAVE AND ASSOCIATED BAND OF SHOWERS/THUNDERSTORMS PER RADAR
MOSAIC ROTATING THROUGH SOUTHWEST WI/NORTHERN IL. CLOUD COVER AND
SCATTERED PRECIPITATION KEEP TEMPERATURES IN THE 70S...BUT WITH VERY
HUMID AIRMASS IN PLACE...FEELING MORE LIKE THE 80S.
FOR TONIGHT...LOW PRESSURE MOVING NORTHEAST OUT OF THE CENTRAL HIGH
PLAINS INTO THE NORTHERN PLAINS WILL DRAG A WARM FRONT NORTHWARD
THROUGH THE REGION. STILL A CHANCE OF A FEW SHOWERS AND
THUNDERSTORMS ALONG THE FRONTAL BOUNDARY...MAINLY ALONG/NORTHEAST OF
I-94 AS EASTERN FLANK OF 850MB MOISTURE TRANSPORT IMPINGES UPON IT.
OTHERWISE...WILL LIKELY SEE SOME STRATUS DEVELOPMENT TONIGHT IN
MOIST SOUTHERLY FLOW. ANY DENSE FOG POTENTIAL LOOKS MINIMAL AT THIS
POINT GIVEN STRENGTHENING SOUTHERLY FLOW TO KEEP THE LOWER BOUNDARY
LAYER SOMEWHAT MIXED. LOOK FOR LOWS TONIGHT IN THE MID/UPPER 60S
ACROSS CENTRAL WI...AND LOWER 70S ELSEWHERE.
LOOKS LIKE THE HEAT IS ON FOR SUNDAY AS WE WILL BE IN THE
WARM/CAPPED WARM SECTOR OF THE NORTHER PLAINS LOW. NAM STILL SHOWING
925MB TEMPERATURES IN THE 28-30C RANGE WEST OF THE MISSISSIPPI AND 25-
28C RANGE ACROSS THE EAST. AFTER SOME INITIAL MORNING
STRATUS...EXPECTING SUNSHINE AND THIS HOT SOUTHERLY FLOW TO PUSH
HIGHS INTO THE MID/UPPER 80S ACROSS CENTRAL WI...AND IN THE LOWER
90S IN THE WI RIVER VALLEY AND AREAS ALONG AND WEST OF THE
MISSISSIPPI RIVER. WITH DEW POINTS IN THE 70-75 DEGREE
RANGE...LOOKING AT HEAT INDICES IN THE 95 TO 105 DEGREE RANGE. AFTER
COLLABORATION WITH SURROUNDING OFFICES AND CRITERIA
CONSIDERATIONS...WILL HOLD OFF ON HEAT HEADLINE FOR NOW AND WILL
CONTINUE TO CONVEY CONCERN VIA OUR HAZARDOUS WEATHER OUTLOOK
AND WEATHER STORY/GRAPHIC PRODUCTS.
A COLD FRONT WILL THEN PUSH INTO THE AREA SUNDAY NIGHT FOR THE
LIKELIHOOD OF THUNDERSTORMS. CANNOT RULE OUT A SEVERE CHANCE GIVEN
HIGHER CAPE ENVIRONMENT AND SUFFICIENT 0-3KM BULK SHEAR IN THE 20-
30KT RANGE. WILL HAVE TO KEEP A CLOSE EYE ON THIS.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 309 PM CDT SAT AUG 23 2014
MEDIUM RANGE MODELS REMAIN IN PRETTY GOOD AGREEMENT WITH FRONTAL
BOUNDARY LINGERING ACROSS THE REGION THROUGH AT LEAST THURSDAY.
MODELS SHOW SEVERAL MID-LEVEL IMPULSES WORKING ON THIS FRONTAL
BOUNDARY FOR CONTINUED SHOWER/THUNDERSTORM CHANCES. WITH PRECIPITABLE
WATER VALUES REMAINING IN THE 1.5-2 INCH RANGE...WILL HAVE TO KEEP
AN EYE ON REPETITIVE CONVECTION POTENTIAL/POSSIBLE LOCALIZED
FLOODING. OTHERWISE...WITH CLOUD COVER AND GOOD CHANCES OF SHOWERS
AND STORMS...PLAN ON HIGH TEMPERATURES STARING OFF IN THE 80-90
DEGREE RANGE MONDAY...COOLING INTO THE LOWER/MIDDLE 70S BY THURSDAY.
SOME TIMING DIFFERENCES THEN ARISE BETWEEN THE GFS AND ECMWF FOR
FRIDAY AND SATURDAY. BOTH MODELS MOVE A MORE VIGOROUS MID-LEVEL
TROUGH THE REGION. GFS IS MUCH FASTER/PROGRESSIVE WITH THIS FEATURE
COMPERED TO THE ECMWF. AT THIS POINT...WILL TAKE A CONSENSUS
APPROACH WHICH YIELDS SMALLER-END SHOWER/THUNDERSTORM CHANCES WITH
HIGHS IN THE 70S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1201 PM CDT SAT AUG 23 2014
THE SHOWERS AND STORMS CONTINUE TO ADVANCE NORTHEAST ACROSS THE
AREA BUT ARE NOW SHOWING A DIMINISHING TREND. EXPECT THAT THESE
WILL BE PAST KRST BY 18Z BUT WILL LINGER INTO THE EARLY AFTERNOON
WITH SOME MVFR CONDITIONS AT KLSE. ONCE THESE MOVE
THROUGH...EXPECT THAT BOTH SITES WILL HAVE VFR CONDITIONS AS A
WARM FRONT APPROACHES AND THEN MOVES THROUGH SWINGING THE WINDS
AROUND TO THE SOUTHEAST. HOWEVER...NO DECREASE IN THE LOW LEVEL
HUMIDITY LEVELS WILL OCCUR WHICH SHOULD PRESENT THE POSSIBILITY OF
IFR CEILINGS WITH LOW STRATUS AGAIN TONIGHT. THE FORECAST
SOUNDINGS FROM THE 23.12Z NAM AND 23.15Z RAP BOTH INDICATING THE
STRATUS SHOULD FORM AND HAVE INCLUDED IT IN BOTH FORECASTS. NOT
OVERLY CONCERNED ABOUT FOG FOR TONIGHT AS BOTH THE SURFACE WINDS
AND WINDS JUST ABOVE THE SURFACE SHOULD BE TOO STRONG WITH TOO
MIXING TO ALLOW IT TO FORM.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1201 PM CDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 954 AM CDT SAT AUG 23 2014
BASED ON THE 23.12Z RAP...NOT REALLY EXPECTING THE COMPLEX OF
SHOWERS AND STORMS TO DISSIPATE ANY TIME SOON. A SHORT WAVE TROUGH
WILL CONTINUE TO SLOWLY MOVE NORTHEAST THROUGH THE AREA PROVIDING
WEAK TO MODERATE PV ADVECTION IN THE 500-300 MB LAYER. IN THE LOW
LEVELS...THE WARM FRONT WILL BE ADVANCING TOWARD THE AREA WITH
WEAK FRONTOGENESIS IN THE 1000-850 MB LAYER THROUGH THE DAY. WARM
AIR ADVECTION OVER THIS FRONT WILL PROVIDE 4 TO 6 UBAR/S OF UP
GLIDE ON THE 310K ISENTROPIC SURFACE. THE MOISTURE TRANSPORT AT
850 MB SHOULD CONTINUE TO BE INTO AND OVER THE WARM FRONT. BASED
ON ALL THIS...HAVE INCREASED THE RAIN CHANCES TO 80 PERCENT OR
HIGHER FOR THE REMAINDER OF THE MORNING WEST OF THE MISSISSIPPI
RIVER AND THEN ALLOWED FOR A SLOW WEAKENING TREND WHILE SPREADING
THE RAIN CHANCES ACROSS MOST OF WISCONSIN DURING THE AFTERNOON.
WILL LET THE DENSE FOG ADVISORY EXPIRE AS SCHEDULED AT 10 AM. MOST
OF THE VISIBILITY HAS IMPROVED TO 2 MILES OR BETTER AND THE
INCOMING RAIN SHOULD ALSO HELP TO CLEAN THE ATMOSPHERE UP A LITTLE
BIT.
UPDATE ISSUED AT 737 AM CDT SAT AUG 23 2014
A SHORT WAVE TROUGH CONTINUES TO MOVE NORTHEAST TOWARD THE
FORECAST AREA THIS MORNING. THE HRRR SEEMS TO HAVE THE BEST HANDLE
ON ITS PRECIPITATION...SO TRENDED THE FORECAST TOWARD IT. AS THE
SYSTEM MOVES INTO OUR AREA THIS EXPECT TO SEE A GRADUAL SPLIT AS
THE 850 TO 700 MB MOISTURE TRANSPORT BREAKS APART AND ONE PART
GOES ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN...AND THE OTHER
PIECE MOVES TO THE WEST OF OUR AREA. SO EXPECT THE AREA WHICH
MOVES INTO SOUTHEAST MINNESOTA TO DISSPATE. MEANWHILE THE BETTER
CHANCES OF PRECIPITATION WILL BE SOUTH OF INTERSTATE 90 AS THAT
JET VEERS THROUGH THAT AREA. THERE MAY BE A REMNANT MCV THAT
KEEPS SOME PRECIPITATION ACROSS WESTERN WISCONSIN THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 330 AM CDT SAT AUG 23 2014
SFC BOUNDARY LIES...MORE OR LESS...WEST EAST ACROSS SOUTHERN IA INTO
CENTRAL ILL EARLY THIS MORNING. AN UPPER LEVEL TROUGH WILL LIFT
NORTHEAST ACROSS THE NORTHERN PLAINS TODAY...AND SHOULD HELP GIVE
THIS BOUNDARY A SHOVE NORTH. MEANWHILE...THERE ARE SUGGESTIONS IN
THE MESO MODELS THAT AN MCV ASSOCIATED WITH THE CURRENT CONVECTION
OVER NEB WOULD TAKE NORTHEAST TRACK TODAY...AND COULD SERVE AS A
FOCUS FOR SHOWER/STORMS DEVELOP AS IT AND THE BOUNDARY SLIDE
NORTH/NORTHEAST ACROSS THE REGION.
HEAT AND HUMIDITY WILL ROUND OUT THE WEEKEND...AND HEAT ADVISORIES
LOOK LIKELY FOR PORTIONS OF THE REGION. 850 MB SREF TEMP ANOMALIES
AROUND +1.5 FOR SUNDAY WHILE 950 MB TEMPS ARE EXPECTED TO WARM TO 26-
28 C. HIGHS SHOULD REACH 90 ACROSS MUCH OF THE FORECAST AREA. ADD IN
DEW POINTS IN THE LOWER 70S AND AFTERNOON HEAT INDICES SHOULD REACH
100 FOR A LARGE PORTION OF THE FORECAST AREA.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT SAT AUG 23 2014
MODELS IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN THROUGH
THE MIDDLE PART OF THE NEW WORK WEEK.
SOLUTIONS SUGGEST AN UPPER LEVEL SHORTWAVE WILL TRACK OUT OF THE
CENTRAL ROCKIES...ACROSS THE NORTHERN PLAINS AND INTO SOUTHERN
CANADA SUNDAY NIGHT. ITS ASSOCIATED SFC COLD FRONT WILL DRAG ACROSS
THE REGION LATE SUNDAY NIGHT INTO MONDAY...WITH THE SOUTHERN EXTENT
LIKELY LINGERING IN A SOUTHWEST-NORTHEAST ORIENTATION OVER THE
REGION. RIPPLES IN THE UPPER LEVEL FLOW WILL KICK OUT OF THE MEAN
TROUGH...AND WORK ON THIS BOUNDARY MON-TUE. THIS NEXT TROUGH THEN
SLIDES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY WED
NIGHT/THU...CONTINUING TO WORK ON THAT SFC BOUNDARY...BUT ALSO
PUSHING IT EAST/SOUTHEAST AS THE SYSTEM EXITS INTO THE EASTERN GREAT
LAKES ON THU NIGHT.
THERE ARE SOME DISCREPANCIES IN THE MODELS WITH PLACEMENT...TIMING
AND STRENGTH OF THIS TROUGH...BUT THE TRENDS ARE SIMILAR AND ALL
POINT TO SEVERAL DAYS WITH RAIN CHANCES.
NOT OVERLY STRONG...BUT FAIRLY PERSISTENT FETCH OF 850 MB MOISTURE
TRANSPORT INTO THE REGION FOR THE EARLY PART OF THE UPCOMING WEEK.
WARM CLOUD DEPTHS CONTINUE TO HOVER NEAR 4 KFT WHILE PWS RANGE FROM
1.5 TO 1.75 INCHES. SO...HEAVY RAIN WOULD BE LIKELY WITH ANY
THUNDERSTORMS...ESPECIALLY THE STRONGER ONES.
AS FOR SEVERE POTENTIAL...AFTERNOON SBCAPES PROGGED FROM 2000-3000
J/KG PER THE GFS INTO WED...MOSTLY AROUND AND SOUTH OF THE SFC
BOUNDARY. HOWEVER...WITH LOW/MID LEVEL WARMING PERSISTING...AND 700
MB TEMPS AROUND 10 C...THERE WILL BE A CAP TO DEAL WITH...AND SOME
OF THIS LOW LEVEL INSTABILITY WILL NOT BE REALIZED. BUFKIT SOUNDINGS
INDICATE THIS TOO. THE DEEPER...STRONGER SHEAR IS EXPECTED TO BE
WELL INTO THE COLD AIR NORTH OF THE BOUNDARY...DISPLACED FROM THE
STRONGER INSTABILITY. THERE IS SOME OVERLAP...SO SOME ENHANCED
UPDRAFTS COULD BE SUPPORTED. OVERALL...NOT SURE THERE IS A TIME
PERIOD THAT STANDS OUT FOR AN ORGANIZED SEVERE THREAT AT THIS TIME.
THERE CERTAINLY COULD BE SOME SEVERE TO MARGINAL SEVERE
STORMS...PERHAPS MORE PULSEY IN NATURE. MUCH DEPENDS ON
BOUNDARY/SHORTWAVE INTERACTION AND TIME OF DAY. LOOK FOR UPDATES IN
THE HWO FOR THE LATEST THOUGHTS ON THE DAY TO DAY SEVERE POTENTIAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1201 PM CDT SAT AUG 23 2014
THE SHOWERS AND STORMS CONTINUE TO ADVANCE NORTHEAST ACROSS THE
AREA BUT ARE NOW SHOWING A DIMINISHING TREND. EXPECT THAT THESE
WILL BE PAST KRST BY 18Z BUT WILL LINGER INTO THE EARLY AFTERNOON
WITH SOME MVFR CONDITIONS AT KLSE. ONCE THESE MOVE
THROUGH...EXPECT THAT BOTH SITES WILL HAVE VFR CONDITIONS AS A
WARM FRONT APPROACHES AND THEN MOVES THROUGH SWINGING THE WINDS
AROUND TO THE SOUTHEAST. HOWEVER...NO DECREASE IN THE LOW LEVEL
HUMIDITY LEVELS WILL OCCUR WHICH SHOULD PRESENT THE POSSIBILITY OF
IFR CEILINGS WITH LOW STRATUS AGAIN TONIGHT. THE FORECAST
SOUNDINGS FROM THE 23.12Z NAM AND 23.15Z RAP BOTH INDICATING THE
STRATUS SHOULD FORM AND HAVE INCLUDED IT IN BOTH FORECASTS. NOT
OVERLY CONCERNED ABOUT FOG FOR TONIGHT AS BOTH THE SURFACE WINDS
AND WINDS JUST ABOVE THE SURFACE SHOULD BE TOO STRONG WITH TOO
MIXING TO ALLOW IT TO FORM.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...04
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
954 AM CDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 954 AM CDT SAT AUG 23 2014
BASED ON THE 23.12Z RAP...NOT REALLY EXPECTING THE COMPLEX OF
SHOWERS AND STORMS TO DISSIPATE ANY TIME SOON. A SHORT WAVE TROUGH
WILL CONTINUE TO SLOWLY MOVE NORTHEAST THROUGH THE AREA PROVIDING
WEAK TO MODERATE PV ADVECTION IN THE 500-300 MB LAYER. IN THE LOW
LEVELS...THE WARM FRONT WILL BE ADVANCING TOWARD THE AREA WITH
WEAK FRONTOGENESIS IN THE 1000-850 MB LAYER THROUGH THE DAY. WARM
AIR ADVECTION OVER THIS FRONT WILL PROVIDE 4 TO 6 UBAR/S OF UP
GLIDE ON THE 310K ISENTROPIC SURFACE. THE MOISTURE TRANSPORT AT
850 MB SHOULD CONTINUE TO BE INTO AND OVER THE WARM FRONT. BASED
ON ALL THIS...HAVE INCREASED THE RAIN CHANCES TO 80 PERCENT OR
HIGHER FOR THE REMAINDER OF THE MORNING WEST OF THE MISSISSIPPI
RIVER AND THEN ALLOWED FOR A SLOW WEAKENING TREND WHILE SPREADING
THE RAIN CHANCES ACROSS MOST OF WISCONSIN DURING THE AFTERNOON.
WILL LET THE DENSE FOG ADVISORY EXPIRE AS SCHEDULED AT 10 AM. MOST
OF THE VISIBILITY HAS IMPROVED TO 2 MILES OR BETTER AND THE
INCOMING RAIN SHOULD ALSO HELP TO CLEAN THE ATMOSPHERE UP A LITTLE
BIT.
UPDATE ISSUED AT 737 AM CDT SAT AUG 23 2014
A SHORT WAVE TROUGH CONTINUES TO MOVE NORTHEAST TOWARD THE
FORECAST AREA THIS MORNING. THE HRRR SEEMS TO HAVE THE BEST HANDLE
ON ITS PRECIPITATION...SO TRENDED THE FORECAST TOWARD IT. AS THE
SYSTEM MOVES INTO OUR AREA THIS EXPECT TO SEE A GRADUAL SPLIT AS
THE 850 TO 700 MB MOISTURE TRANSPORT BREAKS APART AND ONE PART
GOES ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN...AND THE OTHER
PIECE MOVES TO THE WEST OF OUR AREA. SO EXPECT THE AREA WHICH
MOVES INTO SOUTHEAST MINNESOTA TO DISSPATE. MEANWHILE THE BETTER
CHANCES OF PRECIPITATION WILL BE SOUTH OF INTERSTATE 90 AS THAT
JET VEERS THROUGH THAT AREA. THERE MAY BE A REMNANT MCV THAT
KEEPS SOME PRECIPITATION ACROSS WESTERN WISCONSIN THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 330 AM CDT SAT AUG 23 2014
SFC BOUNDARY LIES...MORE OR LESS...WEST EAST ACROSS SOUTHERN IA INTO
CENTRAL ILL EARLY THIS MORNING. AN UPPER LEVEL TROUGH WILL LIFT
NORTHEAST ACROSS THE NORTHERN PLAINS TODAY...AND SHOULD HELP GIVE
THIS BOUNDARY A SHOVE NORTH. MEANWHILE...THERE ARE SUGGESTIONS IN
THE MESO MODELS THAT AN MCV ASSOCIATED WITH THE CURRENT CONVECTION
OVER NEB WOULD TAKE NORTHEAST TRACK TODAY...AND COULD SERVE AS A
FOCUS FOR SHOWER/STORMS DEVELOP AS IT AND THE BOUNDARY SLIDE
NORTH/NORTHEAST ACROSS THE REGION.
HEAT AND HUMIDITY WILL ROUND OUT THE WEEKEND...AND HEAT ADVISORIES
LOOK LIKELY FOR PORTIONS OF THE REGION. 850 MB SREF TEMP ANOMALIES
AROUND +1.5 FOR SUNDAY WHILE 950 MB TEMPS ARE EXPECTED TO WARM TO 26-
28 C. HIGHS SHOULD REACH 90 ACROSS MUCH OF THE FORECAST AREA. ADD IN
DEW POINTS IN THE LOWER 70S AND AFTERNOON HEAT INDICES SHOULD REACH
100 FOR A LARGE PORTION OF THE FORECAST AREA.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT SAT AUG 23 2014
MODELS IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN THROUGH
THE MIDDLE PART OF THE NEW WORK WEEK.
SOLUTIONS SUGGEST AN UPPER LEVEL SHORTWAVE WILL TRACK OUT OF THE
CENTRAL ROCKIES...ACROSS THE NORTHERN PLAINS AND INTO SOUTHERN
CANADA SUNDAY NIGHT. ITS ASSOCIATED SFC COLD FRONT WILL DRAG ACROSS
THE REGION LATE SUNDAY NIGHT INTO MONDAY...WITH THE SOUTHERN EXTENT
LIKELY LINGERING IN A SOUTHWEST-NORTHEAST ORIENTATION OVER THE
REGION. RIPPLES IN THE UPPER LEVEL FLOW WILL KICK OUT OF THE MEAN
TROUGH...AND WORK ON THIS BOUNDARY MON-TUE. THIS NEXT TROUGH THEN
SLIDES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY WED
NIGHT/THU...CONTINUING TO WORK ON THAT SFC BOUNDARY...BUT ALSO
PUSHING IT EAST/SOUTHEAST AS THE SYSTEM EXITS INTO THE EASTERN GREAT
LAKES ON THU NIGHT.
THERE ARE SOME DISCREPANCIES IN THE MODELS WITH PLACEMENT...TIMING
AND STRENGTH OF THIS TROUGH...BUT THE TRENDS ARE SIMILAR AND ALL
POINT TO SEVERAL DAYS WITH RAIN CHANCES.
NOT OVERLY STRONG...BUT FAIRLY PERSISTENT FETCH OF 850 MB MOISTURE
TRANSPORT INTO THE REGION FOR THE EARLY PART OF THE UPCOMING WEEK.
WARM CLOUD DEPTHS CONTINUE TO HOVER NEAR 4 KFT WHILE PWS RANGE FROM
1.5 TO 1.75 INCHES. SO...HEAVY RAIN WOULD BE LIKELY WITH ANY
THUNDERSTORMS...ESPECIALLY THE STRONGER ONES.
AS FOR SEVERE POTENTIAL...AFTERNOON SBCAPES PROGGED FROM 2000-3000
J/KG PER THE GFS INTO WED...MOSTLY AROUND AND SOUTH OF THE SFC
BOUNDARY. HOWEVER...WITH LOW/MID LEVEL WARMING PERSISTING...AND 700
MB TEMPS AROUND 10 C...THERE WILL BE A CAP TO DEAL WITH...AND SOME
OF THIS LOW LEVEL INSTABILITY WILL NOT BE REALIZED. BUFKIT SOUNDINGS
INDICATE THIS TOO. THE DEEPER...STRONGER SHEAR IS EXPECTED TO BE
WELL INTO THE COLD AIR NORTH OF THE BOUNDARY...DISPLACED FROM THE
STRONGER INSTABILITY. THERE IS SOME OVERLAP...SO SOME ENHANCED
UPDRAFTS COULD BE SUPPORTED. OVERALL...NOT SURE THERE IS A TIME
PERIOD THAT STANDS OUT FOR AN ORGANIZED SEVERE THREAT AT THIS TIME.
THERE CERTAINLY COULD BE SOME SEVERE TO MARGINAL SEVERE
STORMS...PERHAPS MORE PULSEY IN NATURE. MUCH DEPENDS ON
BOUNDARY/SHORTWAVE INTERACTION AND TIME OF DAY. LOOK FOR UPDATES IN
THE HWO FOR THE LATEST THOUGHTS ON THE DAY TO DAY SEVERE POTENTIAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 737 AM CDT SAT AUG 23 2014
KLSE WILL KEEP THE IFR STRATUS DECK THROUGH 23.13Z...AND THEN IT
WILL SLOWLY RISE BECOMING MVFR BY 23.15Z AND VFR BY 23.19Z. WITH
THE LINE OF CONVECTION EXPECTED TO SHEAR APART BEFORE REACHING
KLSE WENT DRY FOR NOW.
THE DENSE FOG AT KRST WILL GRADUALLY LIFT INTO A IFR/MVFR DECK BY
23.15Z...AND THEN THE CEILINGS WILL BECOME MVFR AND REMAIN THAT
WAY THROUGH 24.00Z. IT DOES NOT LOOK THE BAND OF SHOWERS WILL
BREAK UP PRIOR TO REACHING KRST...SO INCLUDED VICINITY SHOWERS
BETWEEN 23.17Z AND 23.19Z.
VFR CONTIONS ARE CONDITIONS ARE EXEPCTED AT BOTH SITES THIS
EVENING...AND THEN THE MODELS SUGGEST DENSE FOG AGAIN. HOWEVER
LOOKING AT THE WIND IN THE SOUNDINGS NOT BUYING INTO THIS...SO
JUST KEPT THINGS VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...04
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
738 AM CDT SAT AUG 23 2014
.UPDATE...
ISSUED AT 737 AM CDT SAT AUG 23 2014
A SHORT WAVE TROUGH CONTINUES TO MOVE NORTHEAST TOWARD THE
FORECAST AREA THIS MORNING. THE HRRR SEEMS TO HAVE THE BEST HANDLE
ON ITS PRECIPITATION...SO TRENDED THE FORECAST TOWARD IT. AS THE
SYSTEM MOVES INTO OUR AREA THIS EXPECT TO SEE A GRADUAL SPLIT AS
THE 850 TO 700 MB MOISTURE TRANSPORT BREAKS APART AND ONE PART
GOES ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN...AND THE OTHER
PIECE MOVES TO THE WEST OF OUR AREA. SO EXPECT THE AREA WHICH
MOVES INTO SOUTHEAST MINNESOTA TO DISSPATE. MEANWHILE THE BETTER
CHANCES OF PRECIPITATION WILL BE SOUTH OF INTERSTATE 90 AS THAT
JET VEERS THROUGH THAT AREA. THERE MAY BE A REMNANT MCV THAT
KEEPS SOME PRECIPITATION ACROSS WESTERN WISCONSIN THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 330 AM CDT SAT AUG 23 2014
SFC BOUNDARY LIES...MORE OR LESS...WEST EAST ACROSS SOUTHERN IA INTO
CENTRAL ILL EARLY THIS MORNING. AN UPPER LEVEL TROUGH WILL LIFT
NORTHEAST ACROSS THE NORTHERN PLAINS TODAY...AND SHOULD HELP GIVE
THIS BOUNDARY A SHOVE NORTH. MEANWHILE...THERE ARE SUGGESTIONS IN
THE MESO MODELS THAT AN MCV ASSOCIATED WITH THE CURRENT CONVECTION
OVER NEB WOULD TAKE NORTHEAST TRACK TODAY...AND COULD SERVE AS A
FOCUS FOR SHOWER/STORMS DEVELOP AS IT AND THE BOUNDARY SLIDE
NORTH/NORTHEAST ACROSS THE REGION.
HEAT AND HUMIDITY WILL ROUND OUT THE WEEKEND...AND HEAT ADVISORIES
LOOK LIKELY FOR PORTIONS OF THE REGION. 850 MB SREF TEMP ANOMALIES
AROUND +1.5 FOR SUNDAY WHILE 950 MB TEMPS ARE EXPECTED TO WARM TO 26-
28 C. HIGHS SHOULD REACH 90 ACROSS MUCH OF THE FORECAST AREA. ADD IN
DEW POINTS IN THE LOWER 70S AND AFTERNOON HEAT INDICES SHOULD REACH
100 FOR A LARGE PORTION OF THE FORECAST AREA.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT SAT AUG 23 2014
MODELS IN PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN THROUGH
THE MIDDLE PART OF THE NEW WORK WEEK.
SOLUTIONS SUGGEST AN UPPER LEVEL SHORTWAVE WILL TRACK OUT OF THE
CENTRAL ROCKIES...ACROSS THE NORTHERN PLAINS AND INTO SOUTHERN
CANADA SUNDAY NIGHT. ITS ASSOCIATED SFC COLD FRONT WILL DRAG ACROSS
THE REGION LATE SUNDAY NIGHT INTO MONDAY...WITH THE SOUTHERN EXTENT
LIKELY LINGERING IN A SOUTHWEST-NORTHEAST ORIENTATION OVER THE
REGION. RIPPLES IN THE UPPER LEVEL FLOW WILL KICK OUT OF THE MEAN
TROUGH...AND WORK ON THIS BOUNDARY MON-TUE. THIS NEXT TROUGH THEN
SLIDES ACROSS THE UPPER MISSISSIPPI RIVER VALLEY WED
NIGHT/THU...CONTINUING TO WORK ON THAT SFC BOUNDARY...BUT ALSO
PUSHING IT EAST/SOUTHEAST AS THE SYSTEM EXITS INTO THE EASTERN GREAT
LAKES ON THU NIGHT.
THERE ARE SOME DISCREPANCIES IN THE MODELS WITH PLACEMENT...TIMING
AND STRENGTH OF THIS TROUGH...BUT THE TRENDS ARE SIMILAR AND ALL
POINT TO SEVERAL DAYS WITH RAIN CHANCES.
NOT OVERLY STRONG...BUT FAIRLY PERSISTENT FETCH OF 850 MB MOISTURE
TRANSPORT INTO THE REGION FOR THE EARLY PART OF THE UPCOMING WEEK.
WARM CLOUD DEPTHS CONTINUE TO HOVER NEAR 4 KFT WHILE PWS RANGE FROM
1.5 TO 1.75 INCHES. SO...HEAVY RAIN WOULD BE LIKELY WITH ANY
THUNDERSTORMS...ESPECIALLY THE STRONGER ONES.
AS FOR SEVERE POTENTIAL...AFTERNOON SBCAPES PROGGED FROM 2000-3000
J/KG PER THE GFS INTO WED...MOSTLY AROUND AND SOUTH OF THE SFC
BOUNDARY. HOWEVER...WITH LOW/MID LEVEL WARMING PERSISTING...AND 700
MB TEMPS AROUND 10 C...THERE WILL BE A CAP TO DEAL WITH...AND SOME
OF THIS LOW LEVEL INSTABILITY WILL NOT BE REALIZED. BUFKIT SOUNDINGS
INDICATE THIS TOO. THE DEEPER...STRONGER SHEAR IS EXPECTED TO BE
WELL INTO THE COLD AIR NORTH OF THE BOUNDARY...DISPLACED FROM THE
STRONGER INSTABILITY. THERE IS SOME OVERLAP...SO SOME ENHANCED
UPDRAFTS COULD BE SUPPORTED. OVERALL...NOT SURE THERE IS A TIME
PERIOD THAT STANDS OUT FOR AN ORGANIZED SEVERE THREAT AT THIS TIME.
THERE CERTAINLY COULD BE SOME SEVERE TO MARGINAL SEVERE
STORMS...PERHAPS MORE PULSEY IN NATURE. MUCH DEPENDS ON
BOUNDARY/SHORTWAVE INTERACTION AND TIME OF DAY. LOOK FOR UPDATES IN
THE HWO FOR THE LATEST THOUGHTS ON THE DAY TO DAY SEVERE POTENTIAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 737 AM CDT SAT AUG 23 2014
KLSE WILL KEEP THE IFR STRATUS DECK THROUGH 23.13Z...AND THEN IT
WILL SLOWLY RISE BECOMING MVFR BY 23.15Z AND VFR BY 23.19Z. WITH
THE LINE OF CONVECTION EXPECTED TO SHEAR APART BEFORE REACHING
KLSE WENT DRY FOR NOW.
THE DENSE FOG AT KRST WILL GRADUALLY LIFT INTO A IFR/MVFR DECK BY
23.15Z...AND THEN THE CEILINGS WILL BECOME MVFR AND REMAIN THAT
WAY THROUGH 24.00Z. IT DOES NOT LOOK THE BAND OF SHOWERS WILL
BREAK UP PRIOR TO REACHING KRST...SO INCLUDED VICINITY SHOWERS
BETWEEN 23.17Z AND 23.19Z.
VFR CONTIONS ARE CONDITIONS ARE EXEPCTED AT BOTH SITES THIS
EVENING...AND THEN THE MODELS SUGGEST DENSE FOG AGAIN. HOWEVER
LOOKING AT THE WIND IN THE SOUNDINGS NOT BUYING INTO THIS...SO
JUST KEPT THINGS VFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ079-
086>088-094>096.
IA...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR IAZ010-011-
030.
&&
$$
UPDATE...BOYNE
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1102 PM MDT FRI AUG 22 2014
.UPDATE...
ISSUED AT 807 PM MDT FRI AUG 22 2014
A PRONOUNCED MIDLVL SHORTWAVE CONTINUES TO LIFT NORTHEAST ACROSS
CENTRAL CO THIS EVENING PER RECENT WATER VAPOR IMAGERY. REGIONAL
RADAR MOSAIC SHOWS A BAND OF MODERATE RAIN AND EMBEDDED TSTMS HAS
DEVELOPED OVER THE WESTERN NE PANHANDLE...LIKELY SUPPORTED BY A
MESOSCALE VORTEX CURRENTLY IN THE VICINITY OF AKO. THIS AREA OF
PCPN IS EXPECTED TO SHIFT NORTH AND EAST WITH TIME...SO HAVE THE
CATEGORICAL POPS CONFINED TO AREAS ALONG AND SOUTHEAST OF A LINE
FROM IBM TO SNY IN OUR CWA. PCPN INTENSITY SHOULD NOT BE
PARTICULARLY HEAVY TONIGHT AS INSTABILITY WAS MITIGATED BY
EXTENSIVE CLOUD COVER EARLIER TODAY. THINKING ANY THREAT FOR FLASH
FLOODING IS RATHER LOW. NOT SURE HOW WIDESPREAD CONVECTION WILL BE
ELSEWHERE...BUT ENOUGH MOISTURE IN MONSOONAL FLOW COMBINED WITH
LARGER SCALE SUPPORT SUGGESTS A CONTINUED THREAT FOR ISOLATED TO
SCATTERED SHOWERS FOR MOST OF THE NIGHT. FOG COULD BE A CONCERN
TONIGHT...AND WEBCAMS HAVE ALREADY SHOWN THIS IN THE LARAMIE RANGE
FOOTHILLS. DO NOT THINK THIS WILL LAST LONG AS ALL MODEL GUIDANCE
SHOWS LLVL WINDS SHIFTING TO THE SOUTHWEST. FARTHER E...TRUE FOG
IS UNLIKELY WITH MODERATE PCPN. OPTED NOT TO INCLUDE IN THE GRIDS
ATTM BUT WILL CONTINUE TO MONITOR. ONLY OTHER CHANGE TO THE FCST
WAS TO BUMP LOW TEMPS UP A FEW DEGREES WHERE THE MAIN PCPN BAND IS
SETTING UP. DO NOT EXPECT MUCH FOR RADIATIONAL COOLING THERE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 300 PM MDT FRI AUG 22 2014
PRETTY ACTIVE THE NEXT 24 TO 48 HOURS. TEMPERATURES AND POPS ARE
THE FORECAST CHALLENGES FOR THE SHORT TERM.
CURRENTLY...WATER VAPOR IMAGERY SHOWING A PRETTY PRONOUNCED WAVE
IN THE MONSOONAL FLOW MOVING NORTH THIS AFTERNOON OUT OF NEW
MEXICO INTO WEST CENTRAL COLORADO. MOSAIC RADAR SHOWING WIDESPREAD
SHOWERS OVER CENTRAL COLORADO EARLY THIS AFTERNOON WITH A GENERAL
NORTH NORTHEAST MOVEMENT ON THE CELLS. INFRARED RADAR SHOWING
COOLING CLOUD TOPS WITH THIS WAVE AND WE ARE SEEING AN UPTICK IN
LIGHTNING STRIKES ACROSS WESTERN COLORADO. UPPER LOW OVER IDAHO
FAIRLY DYNAMIC AS WELL WITH NUMEROUS LIGHTNING STRIKES DEVELOPING.
LATEST SPC MESOANALYSIS SHOWING A SLOW EROSION OF CIN OVER EXTREME
SOUTHEAST WYOMING INTO THE KIMBALL AREA...WITH CAPE VALUES
AROUND 1000 J/KG ABOVE. LOOKING AT CLOUD COVER OVERHEAD...IT IS
PRETTY DENSE AND WE HAVE BEEN HARD PRESSED TO GET MUCH WARMING SO
FAR TODAY. 1 PM TEMPERATURES HERE AT THE OFFICE AT 69 DEGREES WITH
LOW TO MID 70S OUT IN THE PANHANDLE.
FOR THIS EVENING...SHORTWAVE BEGINS TO MOVE INTO SOUTHEAST WYOMING
SHORTLY AFTER 00Z WITH GUIDANCE INDICATING FAIRLY WIDESPREAD
CONVECTION DEVELOPING AS THIS HAPPENS. THE 16Z HRRR FORECAST HAS
CONVECTION DEVELOPING HERE AT CHEYENNE AROUND THE 22Z
TIME FRAME...THEN EXPANDING ACROSS SOUTHERN WYOMING INTO THE
PANHANDLE AFTER WARDS. BY 01Z...MOST LOCATIONS EAST OF THE LARAMIE
RANGE SHOULD BE SEEING MEASURABLE RAINFALL WITH SCATTERED SHOWERS
OUT WEST. NAM SOUNDINGS FOR THE PANHANDLE SHOWING PRETTY STRONG
SHEAR OUT IN THE PANHANDLE THIS EVENING. LOOKING AT EASTERLY WINDS
NEAR THE SURFACE OF 15 TO 20KTS WITH SOUTHWEST 40-45KTS AT 6KM.
EVENING SHIFT WILL DEFINITELY NEED TO BE WATCHING FOR SEVERE
THUNDERSTORMS. 0-3KM HELICITY FOR SIDNEY AT 386M2/S2 AT 00Z. GIVEN
THE THICK CLOUD COVER THOUGH...CHANCES ARE DIMMING THAT WE WILL
SEE SEVERE THUNDERSTORMS.
SOMETHING ELSE FOR THIS AFTN/EVE...PRECIPITABLE WATER VALUES
REALLY HIGH FOR THE PANHANDLE. SIDNEY SOUNDING SHOWING 1.42
INCHES...EXTENDING UP TO CHADRON AT 1.40 INCHES. FORECAST QPF
REALLY HIGH FOR THE PANHANDLE AND EXTREME EASTERN WYOMING TONIGHT.
GOOD NEWS IS FORECAST STORM MOTIONS ARE FROM THE SOUTHWEST AT
14-16KTS...SO THESE STORMS SHOULD BE MOVING FAIRLY FAST. WILL NEED
TO WATCH THOUGH FOR TRAINING THUNDERSTORMS AND THERE COULD BE SOME
FLASH FLOODING FOR SOME AREAS THIS EVENING.
GFS AND ECMWF HAVE COME INTO DECENT AGREEMENT WITH THE UPSTREAM
LOW ON THIS 12Z RUN. BOTH SHOWING THE CLOSED LOW MOVING PRETTY
SLOW THROUGH NORTHERN WYOMING THROUGH THE DAY SATURDAY. MOST OF
SATURDAY WILL SEE SHOWERS LASTING MOST OF THE DAY. WENT
SIGNIFICANTLY HIGHER ON POPS OVER GUIDANCE. DO BELIEVE THE MID
SHIFT WILL PROBABLY WANT TO GO HIGHER.
FINALLY SATURDAY EVENING...THE UPPER LOW MOVES OFF INTO SOUTH
DAKOTA WITH RAIN ENDING FROM WEST TO EAST. GOING TO BE PRETTY COOL
WITH 700MB TEMPERATURES DOWN TO +6C SATURDAY NIGHT. SHOULD SEE
WIDESPREAD 40S OUT WEST FOR LOWS...WITH LOW 50S EAST. CLOUD COVER
COULD PROVIDE SLIGHTLY WARMER TEMPERATURES...WE WILL HAVE TO SEE
AS THE EVENT GETS CLOSER. DID GO UNDER GUIDANCE FOR SUNDAY
LOWS...ESPECIALLY OUT WEST WHERE CLOUD COVER WOULD BE LESS.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 335 PM MDT FRI AUG 22 2014
MEDIUM RANGE MODELS IN GOOD AGREEMENT THROUGH EARLY TUESDAY...BUT
THEN SOLUTIONS BEGIN TO DIVERGE THROUGH WEDNESDAY...WITH POOR
CONSISTENCY BETWEEN THE 12Z AND 00Z MODEL RUNS APPARENT INTO LATE
NEXT WEEK. EARLY IN THE WEEK...MOIST SOUTHWEST FLOW AHEAD OF A
POSITIVELY TILTED UPPER LEVEL TROUGH WILL MOVE ACROSS ACROSS THE
IDAHO AND INTO WESTERN WYOMING. A WEAK BOUNDARY WILL DEVELOP AND
DRIFT WESTWARD ALONG THE LARAMIE RANGE...WHICH WILL RESULT IN
UPSLOPE FLOW AND ENHANCE LIFT ACROSS THE HIGH PLAINS. KEPT POP
BETWEEN 35 TO 60 PERCENT ACROSS THE AREA WITH A GOOD CHANCE OF AT
LEAST SCATTERED SHOWERS AND THUNDERSTORMS. ALL MODELS SHOW THIS
ACTIVITY LINGERING THROUGH MONDAY NIGHT AS WELL AS A WAVE OF LOW
PRESSURE DEVELOPS ALONG THE BOUNDARY...WHICH WILL EVENTUALLY
TRANSITION INTO A COLD FRONT. KEPT POP AROUND 50 PERCENT MONDAY
NIGHT. WILL HAVE TO WATCH FOR STRONG TO SEVERE THUNDERSTORMS
MONDAY EVENING WITH CAPE VALUES AROUND 1500 TO 2000 J/KG...HIGH
PW/S...AND INSTABILITY.
ECMWF STILL TRENDING SLOWER WITH THE UPPER LEVEL TROUGH COMPARED
TO THE GFS. THE GEM HAS TRENDED TOWARDS THE ECMWF WHILE THE GFS
PUSHES THE TROUGH THROUGH THE FORECAST AREA AS EARLY AS TUESDAY
AFTERNOON. THE ECMWF AND GEM SHOW THE TROUGH AXIS MOVING ACROSS
THE AREA LATE TUESDAY NIGHT AND EARLY WEDNESDAY. THE GEM AND ECMWF
SOLUTIONS THEN DIVERGE WITH THE ECMWF SHOWING THE SYSTEM
ATTEMPTING TO CLOSE OFF ON WEDNESDAY. EITHER WAY...EXPECT TUESDAY
AND TUESDAY EVENING TO REMAIN UNSETTLED WITH COOLER THAN NORMAL
TEMPERATURES AND A GOOD CHANCE OF WIDESPREAD RAINFALL. HIGHS MAY
STRUGGLE TO REACH THE MID TO UPPER 60S ON TUESDAY AS 700MB
TEMPERATURES LOWER BELOW 5C AFTER THE FRONT MOVES THROUGH THE
AREA. LOW CONFIDENCE ON THE WEDNESDAY FORECAST DUE TO SIGNIFICANT
MODEL DIFFERENCES. KEPT A SLIGHT CHANCE OF SHOWERS AND TSTORMS FOR
NOW DUE TO TIMING DIFFERENCES...EVEN THOUGH THE ECMWF SOLUTION IS
UNLIKELY TO OCCUR.
MUCH DRIER AIR MOVES INTO THE REGION THURSDAY AND FRIDAY BASED ON
CURRENT MODEL RUNS AS THE RIDGE AXIS REDEVELOPS WEST OF THE ROCKY
MOUNTAINS AND DRIFTS EASTWARD. BASED ON 12Z MODELS...WARMER
TEMPERATURES AND DRY CONDITIONS ARE EXPECTED NEXT WEEK.
HOWEVER...THERE IS A LARGE CONTRAST BETWEEN THESE SOLUTIONS AND
THE PREVIOUS 00Z SOLUTIONS FROM LAST NIGHT WHICH SHOW A PACIFIC
SYSTEM MOVES INTO THE REGION WITH ANOTHER STRONG COLD FRONT
ENTERING WYOMING BY LATE FRIDAY. KEPT TEMPERATURES NEAR NORMAL FOR
NOW WITH POP BELOW 10 PERCENT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY EVENING)
ISSUED AT 1059 PM MDT FRI AUG 22 2014
IFR CIGS WILL OCCUR OVER PORTIONS OF SOUTHEAST WYOMING AND MUCH OF
THE NEBRASKA PANHANDLE TONIGHT. FOG IS ALSO EXPECTED LATE TONIGHT
THROUGH MID MORNING SATURDAY WITH POCKETS SOME LIFR. ANOTHER ROUND
OF SHOWERS AND THUNDERSTORMS EXPECTED FOR SATURDAY AFTERNOON AND
EVENING.
&&
.FIRE WEATHER...
ISSUED AT 300 PM MDT FRI AUG 22 2014
MINIMAL FIRE WEATHER CONCERNS ACROSS THE AREA THROUGH THE NEXT FEW
DAYS. UPPER LOW PRESSURE OVER IDAHO THIS AFTERNOON WILL BRING
INCREASING MONSOONAL MOISTURE AND FAIRLY WIDESPREAD RAINFALL TO
MUCH OF THE AREA TONIGHT INTO SATURDAY. BEST CHANCES FOR WETTING
RAINS WILL BE ALONG AND EAST OF THE LARAMIE RANGE AS WELL AS THE
SNOWY AND SIERRA MADRE RANGES. THE UPPER LOW WILL GRADUALLY MOVE
INTO WESTERN SOUTH DAKOTA EARLY SUNDAY MORNING WITH RAINS ENDING
FROM WEST TO EAST. COOLER TEMPERATURES BEHIND THE LOW WILL KEEP
AFTERNOON HUMIDITIES FAIRLY HIGH WITH EXCELLENT OVERNIGHT
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...HAMMER
SHORT TERM...CLAYCOMB
LONG TERM...TJT
AVIATION...SML
FIRE WEATHER...CLAYCOMB
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
151 AM MDT MON AUG 25 2014
.UPDATE...
ISSUED AT 146 AM MDT MON AUG 25 2014
QUICK UPDATE TO BOOST POPS ACROSS THE CENTRAL ZONES AS ACTIVITY
DEVELOPS ALONG OUTFLOW BOUNDARIES AND EDGE OF DEEPER SHEER TO THE
NORTH. NO OTHER CHANGES ATTM WITH NEW GRIDS OUT SHORTLY.
UPDATE ISSUED AT 1036 PM MDT SUN AUG 24 2014
CONVECTION CONTINUES TO EXPAND IN AREAL COVERAGE ALONG AND NORTH
OF UPPER LEVEL JET LIFTING NORTHEAST ACROSS THE FORECAST AREA
LATE THIS EVENING. FEW STRONGER CELLS DEVELOPING WITH NUMEROUS
OUTFLOW BOUNDARIES KICKING UP STRONGER SFC WINDS. LATEST HRRR RUNS
INDICATE THIS WILL CONTINUE THROUGH THE REMAINDER OF THE NIGHT AND
HAVE MADE SIGNIFICANT ADJUSTMENTS TO POPS GRIDS TO FIT CURRENT
TRENDS AND EXPECTED CONDITIONS FOR THE REMAINDER OF THE NIGHT.
OUTFLOW GUSTS TO 40 MPH POSSIBLE TONIGHT ALONG WITH SMALL HAIL
NEAR THE STRONGER CELLS. OTHERWISE...MORE MUCH NEEDED RAIN FOR THE
NORTHERN PORTIONS OF OUR FORECAST AREA.
UPDATE ISSUED AT 550 PM MDT SUN AUG 24 2014
SHORT TERM UPDATE WILL BE REQUIRED EARLY THIS EVENING AS
CONVECTION HAS INCREASED ACROSS EAST CENTRAL UTAH. THIS ACTIVITY
MAY EXPAND INTO NW COLORADO...POSSIBLY AS FAR AS A LINE FROM MOAB
TO ASPEN. THIS ACTIVITY IS IN RESPONSE TO EMBEDDED DISTURBANCE
ALONG A SHEAR AXIS THAT CUTS ACROSS THE FORECAST AREA THIS
EVENING. RAP AND HRRR MODELS INDICATE THAT SHOWERS AND STORMS
LASTING WELL BEYOND SUNSET WILL OCCUR FROM VERNAL TO ROUTT COUNTY.
IT APPEARS THAT THE LOWER RESOLUTION SUCH AS THE GFS40 IS
SUGGESTING NOCTURNAL CONVECTION AS WELL. UPDATE WILL BE COMING AND
WILL BE LEANING TOWARDS THE RAP/HRRR MODELS.
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 255 PM MDT SUN AUG 24 2014
12Z H5 HAND ANALYSIS SHOWING A BLOCKING RIDGE EXTENDING FROM THE
GULF STATES UP INTO THE CANADIAN MARITIME REGION. AS SUCH LOW
PRESSURE WILL BE ANCHORING IN THE WESTERN STATES TO START OUT THE
NEW WEEK. THE MORE IMPRESSIVE FEATURES SHOWING UP IN WATER VAPOR
THIS AFTERNOON ARE THE PAIR OF LOWS ROTATING AROUND EACH OTHER OVER
MONTANA AND WASHINGTON THIS AFTERNOON. THE FORMER RETREATING
NORTHEASTWARD AND THE LATTER DROPPING SOUTHWARD WHERE IT WILL CARVE
OUT A FAIRLY AMPLIFIED TROUGH THROUGH THE GREAT BASIN BY EARLY
TUESDAY. DERIVED IMAGERY AND RAOB DATA SHOWS A SIGNIFICANT DECREASE
IN MOISTURE THE PAST 24 HOURS AS THE MONSOONAL PLUME HAS BEEN
DIRECTED INTO THE EASTERN PLAINS. AT GJT AND UPSTREAM PWATS ARE
BELOW NORMAL FOR THIS TIME OF YEAR. THERE ARE SOME RETURNS SHOWING
UP ON RADAR WITH LOW LEVEL MOISTURE...MOUNTAIN CIRCULATIONS AND
INSTABILITY BEING ENHANCED BY A JET ALOFT. THE FOCUS FOR OVERNIGHT
SHOULD MAINLY BE ACROSS THE NORTH WHERE VEERING MID LEVEL PROFILES
AND THE PASSING JET MAXIMA WILL ADD JUST ENOUGH ASCENT TO KEEP
NOCTURNAL CONVECTION FIRING. HAVE THROWN OUT THE AGGRESSIVE GFS
QPF OUTPUT ATTM WITH IT NOT VERIFYING SO FAR THIS AFTERNOON. THETA
SURFACES NEAR 315K SHOW DECENT UPGLIDE NORTH OF INTERSTATE 70
TONIGHT WHILE ALSO HINT AT SOME TAP TO THE TROPICAL MOISTURE LEFT
OVER FROM WHAT IS LEFT OF MARIE. THIS TAP DOES NOT LOOK TO GREATLY
ENHANCE THE MOISTURE ADVECTION TONIGHT BUT MAY PLAY SOME ROLE IN
STORM FORMATION OVER THE EASTERN DIVIDE MOUNTAINS FOR MONDAY.
AGAIN MONDAY LOOKS TO BE SOMEWHAT OF A DOWN DAY AS THE JET ALOFT
WEAKENS AND OVERALL PWATS REMAIN BELOW NORMAL. A SMALL RIBBON OF
THE MOISTURE MENTIONED ABOVE LOOKS TO FAVOR CONVECTION OVER THE
CENTRAL DIVIDE MOUNTAINS UNDER CONFLUENT FLOW ALOFT. THIS ALL
HANDLED WELL IN THE GOING GRID FORECAST SO ONLY SMALL TWEAKS
NEEDED. TEMPERATURES SHOULD BE A BIT MORE MILD OVERNIGHT UNDER WAA
AND PUSH SOME 3 TO 7 DEGREES UPWARD FOR TUESDAY. TUESDAY NIGHT THE
FLOW BACKS MORE SOUTHERLY ALOFT AS THE MAIN TROF AXIS BECOME
ORIENTED MORE MERIDIONALLY. MONSOON AND TROPICAL MOISTURE LOOK TO
BE FORCED NORTHWARD IN THIS FLOW AND THERE SHOULD BE AN INCREASE
IN CONVECTION FROM MIDNIGHT TOWARD SUNRISE...SETTING UP A MORE
ACTIVE DAY FOR TUESDAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 255 PM MDT SUN AUG 24 2014
THE CHALLENGE OF THESE PERIODS HAS BEEN THE TIMING AND THEREFORE
THE PLACEMENT OF THE UPPER LOW THAT WILL DIG OVER THE REGION. THE
EC AND NAM ARE IN GOOD AGREEMENT WITH A SLOWER SOLUTION. THE GFS
AND CANADIAN PRODUCE A FASTER PROGRESSION BUT THE GFS IS SLOWER
THAN ITS PREVIOUS RUNS. AS THE UPPER LOW IS DECOUPLED FROM THE
POLAR FRONT JET...THE SLOWEST EC SOLUTION IS PREFERRED. SO
INCREASED STORM COVERAGE AND COOLER TEMPS ARE EXPECTED THROUGH
THURSDAY.
TUESDAY...THE UPPER LOW DUG INTO EASTERN NEVADA ENHANCING A 75KT
JET OVER THIS CWA. MOISTURE SURGES TO OVER AN INCH PRECIPITABLE
WATER VALUES IN SE UTAH. WEDNESDAY THE UPPER LOW SLOWLY PROGRESSES
INTO NE UTAH LOSING JET SUPPORT BUT GAINING CYCLONIC AND DIVERGENT
FLOW ALOFT. PRECIP WATER VALUES REMAIN NEAR ONE INCH. STORM MOTION
ALSO REMAINS BRISKLY TO THE NE AT 20 KTS LIMITING RAINFALL FORM
ANY SINGLE STORM. BY THURSDAY THE LOW CENTER AMBLES TO THE
CONTINENTAL DIVIDE WITH WRAP-AROUND DYNAMICS ACROSS THE NORTHERN
CWA AND THE UPPER FLOW SWITCHING TO NW. SOME NOCTURNAL STORMS ARE
EXPECTED THROUGH THESE PERIODS.
BY FRIDAY THE EC PROGRESSES THE OPENING LOW ONTO THE EASTERN
PLAINS WITH A RIDGE BUILDING IN FROM THE WEST. FRIDAY STORM
ACTIVITY WILL LINGER ALONG THE CONTINENTAL DIVIDE...THEN A DRYING
AND WARMING TREND INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1036 PM MDT SUN AUG 24 2014
SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS NORTHEAST UTAH AND
NORTHWEST COLORADO THROUGH 15Z MONDAY MORNING. GUSTY WINDS TO 40
MPH AND SMALL HAIL WILL OCCUR NEAR THE STRONGEST STORMS. LOCAL
MVFR CIGS POSSIBLE WITH MOUNTAINS BECOMING OBSCURED AT TIMES.
SOUTH OF INTERSTATE 70...VFR CONDITIONS EXPECTED TO PERSIST
THROUGH MIDDAY MONDAY.
AFTER 18Z...SCATTERED SHOWERS AND THUNDERSTORMS WILL REDEVELOP
OVER THE MOUNTAINS WITH ACTIVITY TRANSITIONING OUT OVER THE
VALLEYS AFTER 00Z MONDAY EVENING. WITH ANY STORMS...GUSTY
WINDS...HAIL AND LOWERED CIGS SHOULD BE EXPECTED...WITH MOUNTAIN
TOPS BECOMING OBSCURED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...15
LONG TERM...JOE
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1043 PM MDT SUN AUG 24 2014
.UPDATE...
ISSUED AT 1036 PM MDT SUN AUG 24 2014
CONVECTION CONTINUES TO EXPAND IN AREAL COVERAGE ALONG AND NORTH
OF UPPER LEVEL JET LIFTING NORTHEAST ACROSS THE FORECAST AREA
LATE THIS EVENING. FEW STRONGER CELLS DEVELOPING WITH NUMEROUS
OUTFLOW BOUNDARIES KICKING UP STRONGER SFC WINDS. LATEST HRRR RUNS
INDICATE THIS WILL CONTINUE THROUGH THE REMAINDER OF THE NIGHT AND
HAVE MADE SIGNIFICANT ADJUSTMENTS TO POPS GRIDS TO FIT CURRENT
TRENDS AND EXPECTED CONDITIONS FOR THE REMAINDER OF THE NIGHT.
OUTFLOW GUSTS TO 40 MPH POSSIBLE TONIGHT ALONG WITH SMALL HAIL
NEAR THE STRONGER CELLS. OTHERWISE...MORE MUCH NEEDED RAIN FOR THE
NORTHERN PORTIONS OF OUR FORECAST AREA.
UPDATE ISSUED AT 550 PM MDT SUN AUG 24 2014
SHORT TERM UPDATE WILL BE REQUIRED EARLY THIS EVENING AS
CONVECTION HAS INCREASED ACROSS EAST CENTRAL UTAH. THIS ACTIVITY
MAY EXPAND INTO NW COLORADO...POSSIBLY AS FAR AS A LINE FROM MOAB
TO ASPEN. THIS ACTIVITY IS IN RESPONSE TO EMBEDDED DISTURBANCE
ALONG A SHEAR AXIS THAT CUTS ACROSS THE FORECAST AREA THIS
EVENING. RAP AND HRRR MODELS INDICATE THAT SHOWERS AND STORMS
LASTING WELL BEYOND SUNSET WILL OCCUR FROM VERNAL TO ROUTT COUNTY.
IT APPEARS THAT THE LOWER RESOLUTION SUCH AS THE GFS40 IS
SUGGESTING NOCTURNAL CONVECTION AS WELL. UPDATE WILL BE COMING AND
WILL BE LEANING TOWARDS THE RAP/HRRR MODELS.
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 255 PM MDT SUN AUG 24 2014
12Z H5 HAND ANALYSIS SHOWING A BLOCKING RIDGE EXTENDING FROM THE
GULF STATES UP INTO THE CANADIAN MARITIME REGION. AS SUCH LOW
PRESSURE WILL BE ANCHORING IN THE WESTERN STATES TO START OUT THE
NEW WEEK. THE MORE IMPRESSIVE FEATURES SHOWING UP IN WATER VAPOR
THIS AFTERNOON ARE THE PAIR OF LOWS ROTATING AROUND EACH OTHER OVER
MONTANA AND WASHINGTON THIS AFTERNOON. THE FORMER RETREATING
NORTHEASTWARD AND THE LATTER DROPPING SOUTHWARD WHERE IT WILL CARVE
OUT A FAIRLY AMPLIFIED TROUGH THROUGH THE GREAT BASIN BY EARLY
TUESDAY. DERIVED IMAGERY AND RAOB DATA SHOWS A SIGNIFICANT DECREASE
IN MOISTURE THE PAST 24 HOURS AS THE MONSOONAL PLUME HAS BEEN
DIRECTED INTO THE EASTERN PLAINS. AT GJT AND UPSTREAM PWATS ARE
BELOW NORMAL FOR THIS TIME OF YEAR. THERE ARE SOME RETURNS SHOWING
UP ON RADAR WITH LOW LEVEL MOISTURE...MOUNTAIN CIRCULATIONS AND
INSTABILITY BEING ENHANCED BY A JET ALOFT. THE FOCUS FOR OVERNIGHT
SHOULD MAINLY BE ACROSS THE NORTH WHERE VEERING MID LEVEL PROFILES
AND THE PASSING JET MAXIMA WILL ADD JUST ENOUGH ASCENT TO KEEP
NOCTURNAL CONVECTION FIRING. HAVE THROWN OUT THE AGGRESSIVE GFS
QPF OUTPUT ATTM WITH IT NOT VERIFYING SO FAR THIS AFTERNOON. THETA
SURFACES NEAR 315K SHOW DECENT UPGLIDE NORTH OF INTERSTATE 70
TONIGHT WHILE ALSO HINT AT SOME TAP TO THE TROPICAL MOISTURE LEFT
OVER FROM WHAT IS LEFT OF MARIE. THIS TAP DOES NOT LOOK TO GREATLY
ENHANCE THE MOISTURE ADVECTION TONIGHT BUT MAY PLAY SOME ROLE IN
STORM FORMATION OVER THE EASTERN DIVIDE MOUNTAINS FOR MONDAY.
AGAIN MONDAY LOOKS TO BE SOMEWHAT OF A DOWN DAY AS THE JET ALOFT
WEAKENS AND OVERALL PWATS REMAIN BELOW NORMAL. A SMALL RIBBON OF
THE MOISTURE MENTIONED ABOVE LOOKS TO FAVOR CONVECTION OVER THE
CENTRAL DIVIDE MOUNTAINS UNDER CONFLUENT FLOW ALOFT. THIS ALL
HANDLED WELL IN THE GOING GRID FORECAST SO ONLY SMALL TWEAKS
NEEDED. TEMPERATURES SHOULD BE A BIT MORE MILD OVERNIGHT UNDER WAA
AND PUSH SOME 3 TO 7 DEGREES UPWARD FOR TUESDAY. TUESDAY NIGHT THE
FLOW BACKS MORE SOUTHERLY ALOFT AS THE MAIN TROF AXIS BECOME
ORIENTED MORE MERIDIONALLY. MONSOON AND TROPICAL MOISTURE LOOK TO
BE FORCED NORTHWARD IN THIS FLOW AND THERE SHOULD BE AN INCREASE
IN CONVECTION FROM MIDNIGHT TOWARD SUNRISE...SETTING UP A MORE
ACTIVE DAY FOR TUESDAY.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 255 PM MDT SUN AUG 24 2014
THE CHALLENGE OF THESE PERIODS HAS BEEN THE TIMING AND THEREFORE
THE PLACEMENT OF THE UPPER LOW THAT WILL DIG OVER THE REGION. THE
EC AND NAM ARE IN GOOD AGREEMENT WITH A SLOWER SOLUTION. THE GFS
AND CANADIAN PRODUCE A FASTER PROGRESSION BUT THE GFS IS SLOWER
THAN ITS PREVIOUS RUNS. AS THE UPPER LOW IS DECOUPLED FROM THE
POLAR FRONT JET...THE SLOWEST EC SOLUTION IS PREFERRED. SO
INCREASED STORM COVERAGE AND COOLER TEMPS ARE EXPECTED THROUGH
THURSDAY.
TUESDAY...THE UPPER LOW DUG INTO EASTERN NEVADA ENHANCING A 75KT
JET OVER THIS CWA. MOISTURE SURGES TO OVER AN INCH PRECIPITABLE
WATER VALUES IN SE UTAH. WEDNESDAY THE UPPER LOW SLOWLY PROGRESSES
INTO NE UTAH LOSING JET SUPPORT BUT GAINING CYCLONIC AND DIVERGENT
FLOW ALOFT. PRECIP WATER VALUES REMAIN NEAR ONE INCH. STORM MOTION
ALSO REMAINS BRISKLY TO THE NE AT 20 KTS LIMITING RAINFALL FORM
ANY SINGLE STORM. BY THURSDAY THE LOW CENTER AMBLES TO THE
CONTINENTAL DIVIDE WITH WRAP-AROUND DYNAMICS ACROSS THE NORTHERN
CWA AND THE UPPER FLOW SWITCHING TO NW. SOME NOCTURNAL STORMS ARE
EXPECTED THROUGH THESE PERIODS.
BY FRIDAY THE EC PROGRESSES THE OPENING LOW ONTO THE EASTERN
PLAINS WITH A RIDGE BUILDING IN FROM THE WEST. FRIDAY STORM
ACTIVITY WILL LINGER ALONG THE CONTINENTAL DIVIDE...THEN A DRYING
AND WARMING TREND INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1036 PM MDT SUN AUG 24 2014
SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS NORTHEAST UTAH AND
NORTHWEST COLORADO THROUGH 15Z MONDAY MORNING. GUSTY WINDS TO 40
MPH AND SMALL HAIL WILL OCCUR NEAR THE STRONGEST STORMS. LOCAL
MVFR CIGS POSSIBLE WITH MOUNTAINS BECOMING OBSCURED AT TIMES.
SOUTH OF INTERSTATE 70...VFR CONDITIONS EXPECTED TO PERSIST
THROUGH MIDDAY MONDAY.
AFTER 18Z...SCATTERED SHOWERS AND THUNDERSTORMS WILL REDEVELOP
OVER THE MOUNTAINS WITH ACTIVITY TRANSITIONING OUT OVER THE
VALLEYS AFTER 00Z MONDAY EVENING. WITH ANY STORMS...GUSTY
WINDS...HAIL AND LOWERED CIGS SHOULD BE EXPECTED...WITH MOUNTAIN
TOPS BECOMING OBSCURED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...15
LONG TERM...JOE
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS MIAMI FL
256 AM EDT MON AUG 25 2014
.SHORT TERM (TODAY-WEDNESDAY)...
IT CONTINUES TO LOOK MORE FAVORABLE THAT T.S. CRISTOBAL WILL MOVE
NORTH AND NORTHEAST AWAY FROM SOUTH FLORIDA. SO THE PRIMARY IMPACTS
WILL BE AN INCREASE IN RIP CURRENTS AT THE ATLANTIC BEACHES AND
BUILDING SEAS IN THE ATLANTIC FOR MARINE INTERESTS AS A SMALL
NORTHEAST SWELL IS GENERATED. MODELS SUGGEST A MOISTURE SURGE MOVING
INTO THE REGION AFTER 12Z THIS MORNING WHICH IS A RESULT IN THE
NORTHEAST CIRCULATION DEVELOPING WITH CRISTOBAL. THE CURRENT PWAT IS
AROUND 1.75 INCHES WITH FORECAST SOUNDINGS SHOWING AN INCREASE TO 2+
INCHES THIS MORNING. THE STEERING FLOW WILL BE NORTHEAST TO
SOUTHWEST SO THE EAST COAST COULD GET A QUICK PASSING SHRA/TSRA WITH
THE GREATEST ACTIVITY BEING OVER THE INTERIOR AND SOUTHWEST COAST.
THE HRRR IS SHOWING SOMETHING VERY SIMILAR WITH SCATTERED SHOWERS
NEAR THE EAST COAST WITH A FLARE UP INLAND AROUND THE LAKE AFTER
17Z. MUCH DRIER AIR ALOFT WILL THEN MOVE INTO SOUTH FLORIDA ON
TUESDAY WITH FORECAST SOUNDINGS SHOWING PWAT DROPPING TO LESS THAN
1.25 INCHES WITH THE NORTHEAST STEERING FLOW CONTINUING SO ONLY
ISOLATED OR LOW END SCATTERED IS EXPECTED ACROSS THE INTERIOR AND
SOUTHWEST COAST TUESDAY AFTERNOON/EVENING. THEY DRYING TREND WILL
PERSIST INTO WEDNESDAY ALTHOUGH FORECAST SOUNDINGS DO SHOW A
SLIGHT RETURN OF MOISTURE WITH PWAT CLIMBING BACK TO OVER 1.5
INCHES BY LATE IN THE DAY. STILL, NOT MUCH COVERAGE IS ANTICIPATED
WITH A MORE SOUTHEAST STEERING FLOW PATTERN RETURNING SO STORMS
WOULD TEND TO FORM INLAND FROM THE EAST COAST AND BE CONCENTRATED
OVER THE INTERIOR ONLY.
.LONG TERM (THURSDAY-SUNDAY)...
AS CRISTOBAL EXITS TO THE NORTHEAST, A DEEP LAYER RIDGE WILL BUILD
BACK TO THE NORTH LATE THIS WEEK INTO THE UPCOMING WEEKEND WITH AN
INCREASE IN MOISTURE AND PWATS RETURNING TO NEAR NORMAL VALUES. THIS
WOULD CONTINUE TO STEER THE STORMS AWAY FROM THE EAST COAST TO THE
INTERIOR AND WEST COAST REGIONS. NO OTHER TROPICAL SYSTEMS ARE
EXPECTED TO AFFECT SOUTH FLORIDA THROUGH THE EXTENDED PERIOD.
&&
.MARINE...
NORTHEAST WINDS WILL PREVAIL THROUGH MIDWEEK, STRENGTHENING A TAD
TODAY AND TUESDAY AS THE PRESSURE GRADIENT TIGHTENS. THIS WILL
LEAD TO INCREASING SEAS ESPECIALLY IN THE GULF STREAM OFF THE PALM
BEACH COAST...WHERE HAZARDOUS SEAS OF 7+ FT ARE POSSIBLE DUE TO
FLOW COUNTERACTING THE GULF STREAM CURRENT ALONG WITH AN INCOMING
SMALL NORTHEAST SWELL.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 91 80 91 79 / 40 20 10 10
FORT LAUDERDALE 91 81 92 81 / 40 20 10 10
MIAMI 89 80 91 79 / 60 20 10 10
NAPLES 92 78 93 77 / 60 30 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
SHORT TERM...30/KOB
LONG TERM....30/KOB
AVIATION.....23/SK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
335 AM CDT MON AUG 25 2014
.SYNOPSIS...
ISSUED AT 334 AM CDT MON AUG 25 2014
THUNDERSTORMS HAVE DEVELOPED EARLY THIS MORNING ALONG AND AHEAD OF
THE SURFACE FRONT EXTENDING ROUGHLY FROM WESTERN LAKE SUPERIOR SW
ACROSS WESTERN WI...SW MN...INTO W CENTRAL IA. THIS WAS ALONG AN
AXIS OF HIGH THETAE INDICATED BY 850 MB DEWPOINTS OF 14 TO 16 C FROM
NORTHEAST KS INTO SW ONTARIO AT 00Z...WITH CONVERGENCE ASSISTED
BY 35KT TO 40 KT SW WINDS AT 850 MB. THIS MOISTURE WAS BEING
PULLED NORTHWARD BY A STRONG SURFACE AND UPPER LEVEL LOW SEEN ON
WV IMAGERY ALONG THE ND/MANITOBA BORDER. AT 3 AM...THE LEADING
LINE OF SCATTERED THUNDERSTORMS WAS MOVING INTO BUCHANAN AND
BENTON COUNTIES...INTO A VERY HUMID AIRMASS WITH DEWPOINTS IN THE
LOWER TO MID 70S AND AIR TEMPERATURES IN THE MID TO UPPER 70S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT MON AUG 25 2014
FORECAST CHALLENGES CENTER ON THUNDERSTORMS THIS MORNING AND AGAIN
TONIGHT...AND HEAT HEADLINES TODAY AS THE HOT AND HUMID CONDITIONS
PERSIST OVER THE REGION. IN THE NEAR TERM...A SEMI-LINEAR MCS WILL
LIKELY MOVE ACROSS THE FORECAST AREA MAINLY NORTH OF I-80...DRIVEN
BY A WEAK SHORTWAVE FLOW IN THE NW FLOW ALOFT. WHILE NO INDIVIDUAL
FORECAST MODEL HAS HAD A GOOD HANDLE ON TRENDS OVERNIGHT...THE
HIGH RES WRF AND RAP MODELS APPEAR TO HAVE THE BEST HANDLE ON THE
CONVECTION ENTERING THE NORTH. THESE HAVE THE THUNDERSTORMS ADVANCING
THROUGH THE NORTH OVER THE NEXT SEVERAL HOURS AND THEN DISSIPATING
BY NOON...AND HAVE TRENDED THE FORECAST ACCORDINGLY. THE LATEST
RAP IS ALONE WITH DEVELOPING THUNDERSTORMS IN THE HIGH MUCAPE
AXIS FURTHER SE...OVER 4000 J/KG...OVER W CENTRAL IL TOWARD
SUNRISE...WHICH WHILE NOT IN THE CURRENT FORECAST CANNOT BE
ENTIRELY RULED AND WILL WATCH TRENDS CLOSELY.
OTHERWISE...THIS SHOULD BE FOLLOWED BY CLEARING SKIES AND A RETURN
TO THE HEAT AND HUMIDITY SEEN OVER THE AREA YESTERDAY. DUE TO
UNCERTAINTIES IN THE TIMING OF THE DISSIPATING MCS IN THE NORTH AND
POSSIBLE DEBRIS CLOUDS FROM STORMS IN THE PLAINS...ALONG WITH 850 MB
TEMPERATURES PROGGED ABOUT 1 DEGREE COOLER...HAVE TRENDED HIGHS A
DEGREE OR TWO COOLER THAN SUNDAY...WITH UPPER 80S NW TO LOWER 90S
CENTRAL AND SOUTH. DEWPOINTS WILL HOLD IN THE LOWER TO MID 70S AND
POSSIBLY TOUCH THE UPPER 70S AT TIMES LATE IN THE DAY. THIS
COMBINATION WILL SEND HEAT INDEX VALUES TO JUST ABOVE 100 ACROSS
THE SOUTH AND WILL KEEP THE PREVIOUS HEAT ADVISORY CONFIGURATION
IN PLACE.
TONIGHT...THE SETUP WILL BE FAVORABLE FOR ANOTHER MCS AS THE SURFACE
FRONT SLOWLY ADVANCES THROUGH THE FORECAST AREA AND MODEST
CONVERGENCE OCCURS IN THE 850 MB THETAE AXIS AS IT SHIFTS OVERHEAD.
HAVE KEPT LIKELY POPS IN THE NORTH WITH SLIGHT TO LOW END CHANCE
POPS IN THE SOUTH TOWARD MORNING. THE MAIN THREAT WILL BE LOCALLY
HEAVY RAINFALL. IT WILL BE ANOTHER WARM AND VERY HUMID NIGHT WITH
TEMPERATURES AND DEWPOINTS IN THE 70S...EXCEPT IN THE FAR NW...WHERE
THE CURRENT FRONTAL TIMING SUGGESTS READINGS LOWERING INTO THE
UPPER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 334 AM CDT MON AUG 25 2014
AN ORGANIZED THUNDERSTORM COMPLEX SHOULD MOVE INTO THE AREA TUESDAY
MORNING AND DISSIPATE DURING THE MORNING. BOUNDARIES LEFT OVER FROM
THIS COMPLEX COMBINED WITH A WEAK FRONT MOVING THROUGH THE AREA WILL
PROVIDE THE FOCUS FOR NEW CONVECTION TUESDAY AFTERNOON AND EVENING.
HIGH MOISTURE LEVELS IN THE LOWER ATMOSPHERE MEANS ANY STORM WILL BE
CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL.
CLOUD COVER AND RAIN WILL PLAY INTO HOW WARM IT WILL GET ON TUESDAY.
THE SOUTHEAST HALF MAY SEE TEMPERATURES AROUND 90 WITH HEAT INDEX
READINGS IN THE UPPER 90S TO JUST OVER 100.
ANOTHER THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP IN WESTERN IOWA
TUESDAY EVENING AND THEN MOVE MAINLY EAST OVERNIGHT INTO WEDNESDAY
MORNING. THIS STORM COMPLEX SHOULD ARRIVE IN THE WESTERN THIRD OF
THE CWFA IN THE PRE-DAWN HOURS AND SLOWLY DISSIPATE ACROSS THE AREA
WEDNESDAY MORNING. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE FROM THE
STORMS DUE TO HIGH MOISTURE LEVELS.
LIKE TUESDAY...BOUNDARIES LEFT OVER FROM THE WEDNESDAY STORM COMPLEX
WILL PROVIDE THE FOCUS FOR NEW CONVECTION WEDNESDAY AFTERNOON AND
EVENING.
SIGNALS FROM THE MODELS SUGGEST YET ANOTHER THUNDERSTORM COMPLEX
WILL DEVELOP IN WESTERN IOWA WEDNESDAY EVENING AND MOVE GENERALLY
EAST OVERNIGHT AND ARRIVE IN THE WESTERN THIRD OF THE AREA IN THE
PRE-DAWN HOURS. LOCALLY HEAVY RAINFALL MAY BE POSSIBLE FROM SOME OF
THE STRONGER STORMS.
THURSDAY ON...
THE MODEL CONSENSUS HAS CHANCE POPS IN EACH 12 HOUR PERIOD FROM
THURSDAY THROUGH SATURDAY NIGHT. TEMPERATURES SHOULD BE NEAR NORMAL.
ON SUNDAY...THE MODEL CONSENSUS HAS SLIGHT CHANCE TO LOW CHANCE POPS.
THE LARGE SCALE PICTURE SUGGESTS THE WEATHER PATTERN WILL REMAIN
FAIRLY ACTIVE WITH A FRONT STALLED OUT JUST SOUTH OF THE AREA. IT
WILL NOT RAIN CONTINUOUSLY THE ENTIRE TIME. THERE WILL BE PERIODS OF
DRY WEATHER THAT MAY LAST 6 OR 12 HOURS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1125 PM CDT SUN AUG 24 2014
AN APPROACHING FRONT BRINGS THE THREAT FOR SHOWERS AND
THUNDERSTORMS TO EASTERN IOWA AFTER 08Z LATE TONIGHT. IT IS NOT
CERTAIN THAT THEY WILL IMPACT THE AREA...AND A VCSH IS CONTINUED
TO BE USED TO DESCRIBE THIS LATE NIGHT THREAT WITH TEMPORARY 5SM
TSRA POSSIBLE AT BOTH CID AND DBQ. IF THE LINE OF STORMS VERIFY
OVERNIGHT IN EASTERN IOWA...MVFR CONDITIONS ARE LIKELY TO OCCUR
ESPECIALLY AT CID AND DBQ AND POSSIBLY AT MLI. OTHERWISE...LATE NIGHT
AND EARLY MORNING MVFR FOG IS LIKELY AT ALL SITES DUE TO THE VERY
MOIST AIR MASS IN PLACE IN THE REGION. AFTER 15Z MONDAY...A RETURN
TO HOT VFR WEATHER IS EXPECTED. SOUTH TO SOUTHEAST WINDS OF 5 TO 9
KTS ARE EXPECTED THROUGH THE PERIOD. ANOTHER THREAT FOR A SHOWER
OR STORM WILL ARRIVE BY LATE AFTERNOON MONDAY AND CONTINUE INTO
MONDAY NIGHT.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
LOUISA-MUSCATINE-SCOTT.
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR DES MOINES-HENRY
IA-LEE-VAN BUREN.
IL...HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
BUREAU-HENRY IL-MERCER-PUTNAM-ROCK ISLAND-WHITESIDE.
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR HANCOCK-HENDERSON-
MCDONOUGH-WARREN.
MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...08
AVIATION...ERVIN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
224 AM CDT Mon Aug 25 2014
...Updated long term section...
.SHORT TERM...(Today and tonight)
ISSUED AT 155 AM CDT MON AUG 25 2014
A wedge of warm 850mb to 700mb temperatures that was located just
south of a surface boundary which extended from the Oklahoma
panhandle to northeast Kansas at 00z Monday will lift north today
and by 00z Tuesday this warm air will be located across most of
western and south central Kansas. Based on the the forecast mixing
height and the 00z Tuesday temperatures in the 850mb to 700mb
level from the NAM and GFS it will be another day with highs in
the upper 90s to near 100 degrees across most of western and south
central Kansas.
In addition to the warming temperatures 700mb moisture will also
be improving across central and north central Kansas which may
give rise to some afternoon convection as CAPE values increase to
1000 to 2000 j/kg, especially across northern Kansas. At this time
it appears the better forcing and instability late today along
with the better low level moisture will be near/north the surface
boundary in north central Kansas so will focus late day convection
around and north of the interstate 70 corridor with more widely
scattered storms being possible further south.
Tonight warm air advection and moisture advection improves near
the nose of a developing low level jet. This will be just north of
a surface boundary that will remain nearly stationary early
tonight across west central and north central Kansas. At the same
time an upper level trough is forecast to cross northwest Kansas.
As a result will increase the chances for convection across west
central and north central Kansas, especially north of where the
+12c to +14c 700mb temperature gradient is forecast to be located
by the NAM and GFS at 06z and 12z Tuesday. Preciptable water
values Monday night are forecast to range from 1.5 to 1.75 across
northern Kansas so some storms tonight may produce periods of
heavy rainfall. Also am unable to rule out the chance for some
storms becoming severe Monday evening north of the interstate 70
corridor base on 0-6km shear of 30 to 40 knots and CAPE values
ranging from 1500 to near 3000 j/kg at 00z Tuesday from the NAM
and GFS. Main hazard at this time appears to be quarter size hail
and wind gusts of 60 mph or greater.
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 223 AM CDT MON AUG 25 2014
An upper level low will trek from the Pacific northwest Monday to
the Central Plains by Friday before exiting the area this weekend.
Mid to upper levels of the atmosphere will saturate as this system
approaches bringing increasing cloudiness to western Kansas. Towards
the surface, a frontal boundary is expected to be positioned across
west central Kansas Tuesday before lifting northward to northern
Kansas and Nebraska Wednesday into Thursday. This frontal boundary
will be the main focal point where thunderstorms are expected to
develop. There could also be storms developing along the higher
terrain across eastern Colorado before moving into western Kansas
later on. A cold front is then progged to move through the area
Thursday with wrap around moisture in place Friday. Thunderstorm
chances envelop the CWA Wednesday night through Friday before
tapering off Friday night. A drier pattern then sits up for this
weekend with partly cloudy skies expected. As for temperatures,
highs will start out in the 90s Tuesday and Wednesday before cooling
off into the 80s Thursday through Saturday. Highs Sunday look to top
out in the lower 90s. Lows are forecasted to range from the mid 60s
across west central Kansas to lower 70s across south central Kansas
Tuesday through Thursday morning before cooling off into the 60s
Friday into this weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1205 AM CDT MON AUG 25 2014
A weak surface boundary will lift north across western Kansas
overnight. As this boundary moves into west central and north
central Kansas the surface winds will become south southeast at
around 10 knots by 12z Monday. Based on 03z verification from the
NAM and HRRR will stay close to these models on timing of the wind
shift overnight. Southerly winds will increase to around 15 knots
by the early afternoon. BUFR soundings indicating VRF conditions
will prevail overnight and Monday as moisture around the 700mb
level improves during the Day on Monday. Late day instability and
forcing across north central Kansas may also give rise to some
scattered evening convection but given the scatters nature of the
storms late Monday will not include mention of thunderstorms yet
in the Hays 06z tafs.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 98 69 96 69 / 20 20 30 30
GCK 98 67 94 67 / 20 30 40 40
EHA 96 67 93 67 / 20 20 40 30
LBL 98 69 96 69 / 20 20 30 30
HYS 98 68 94 68 / 30 70 50 50
P28 100 73 99 74 / 10 20 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Burgert
LONG TERM...Hovorka_42
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
159 AM CDT Mon Aug 25 2014
...Updated short term discussion...
.SHORT TERM...(Today and tonight)
ISSUED AT 155 AM CDT MON AUG 25 2014
A wedge of warm 850mb to 700mb temperatures that was located just
south of a surface boundary which extended from the Oklahoma
panhandle to northeast Kansas at 00z Monday will lift north today
and by 00z Tuesday this warm air will be located across most of
western and south central Kansas. Based on the the forecast mixing
height and the 00z Tuesday temperatures in the 850mb to 700mb
level from the NAM and GFS it will be another day with highs in
the upper 90s to near 100 degrees across most of western and south
central Kansas.
In addition to the warming temperatures 700mb moisture will also
be improving across central and north central Kansas which may
give rise to some afternoon convection as CAPE values increase to
1000 to 2000 j/kg, especially across northern Kansas. At this time
it appears the better forcing and instability late today along
with the better low level moisture will be near/north the surface
boundary in north central Kansas so will focus late day convection
around and north of the interstate 70 corridor with more widely
scattered storms being possible further south.
Tonight warm air advection and moisture advection improves near
the nose of a developing low level jet. This will be just north of
a surface boundary that will remain nearly stationary early
tonight across west central and north central Kansas. At the same
time an upper level trough is forecast to cross northwest Kansas.
As a result will increase the chances for convection across west
central and north central Kansas, especially north of where the
+12c to +14c 700mb temperature gradient is forecast to be located
by the NAM and GFS at 06z and 12z Tuesday. Preciptable water
values Monday night are forecast to range from 1.5 to 1.75 across
northern Kansas so some storms tonight may produce periods of
heavy rainfall. Also am unable to rule out the chance for some
storms becoming severe Monday evening north of the interstate 70
corridor base on 0-6km shear of 30 to 40 knots and CAPE values
ranging from 1500 to near 3000 j/kg at 00z Tuesday from the NAM
and GFS. Main hazard at this time appears to be quarter size hail
and wind gusts of 60 mph or greater.
.LONG TERM...(Monday night through Sunday)
ISSUED AT 305 PM CDT SUN AUG 24 2014
An upper level trough will move from Nevada and into the
Intermountain West on Wednesday, then into the Central Plains on
Thursday, and will be slow to exit the Central Plains by Saturday
afternoon. New model runs have this upper system slowing down its
progress and this will allow for thunderstorm chances Tuesday into
Saturday, with the best chances from Tuesday night into Thursday
with a cold front. The storms may linger near to east of Dodge City
on Saturday as the upper wave moves eastward. Severe storm chances
do not look all that favorable with fairly weak upper level wind
fields.
Daytime highs will be warm and in the mid to upper 90s ahead of the
front on Tuesday, then in the low to mid 90s on Wednesday, cooling
into the 80s for Thursday and Friday. Highs warm back up to around
90 for the Weekend. Overnight lows around 70 on Monday night and
Tuesday night cool into the 60s into the Weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1205 AM CDT MON AUG 25 2014
A weak surface boundary will lift north across western Kansas
overnight. As this boundary moves into west central and north
central Kansas the surface winds will become south southeast at
around 10 knots by 12z Monday. Based on 03z verification from the
NAM and HRRR will stay close to these models on timing of the wind
shift overnight. Southerly winds will increase to around 15 knots
by the early afternoon. BUFR soundings indicating VRF conditions
will prevail overnight and Monday as moisture around the 700mb
level improves during the Day on Monday. Late day instability and
forcing across north central Kansas may also give rise to some
scattered evening convection but given the scatters nature of the
storms late Monday will not include mention of thunderstorms yet
in the Hays 06z tafs.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 98 69 96 69 / 20 20 30 30
GCK 98 67 94 67 / 20 30 30 40
EHA 96 67 93 66 / 10 20 40 30
LBL 98 69 95 68 / 10 20 30 30
HYS 98 68 94 69 / 20 70 40 40
P28 100 73 98 74 / 10 20 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Burgert
LONG TERM...Kruse
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1208 AM CDT Mon Aug 25 2014
...Updated synopsis and aviation discussion...
.SYNOPSIS...
ISSUED AT 1205 AM CDT MON AUG 25 2014
At 00z Monday a 500mb ridge axis extended from eastern Texas to
the western Great Lakes region. A 700mb to 500mb low was located
over western North Dakota with a +70 knot 300mb jet extending from
the base of this upper low near northeast Colorado to Minnesota.
Further west southwest another upper level trough was over eastern
Oregon/southwest Idaho and a +90 knot 300mb jet was located on the
west side of this system. Over the Central Plains the 700mb
temperatures at 00z Monday ranged from +9c at North Platte to +13c
at Amarillo. 850mb temperatures ranged from 21C at North Platte to
+28c at Amarillo. A weak surface frontal boundary extended from
the western Oklahoma panhandle to northeast Kansas. An area of mid
60s to around 70 degree surface dew points were located just north
of this surface boundary which stretched from north central Kansas
to southeast Nebraska. 850mb and 700mb moisture axis was located
from eastern Oklahoma to southeast Nebraska.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 320 PM CDT SUN AUG 24 2014
A strong shortwave trough was ejecting northeastward into the
northern plains this afternoon. The associated cold front had pushed
into southwest Kansas and stalled out. A few thunderstorms can`t be
ruled out in south central Kansas this evening ahead of the cold
front. Some elevated shower activity may develop tonight along the
Interstate 70 corridor to the south of the upper level jet streak;
but most of the precipitation should stay farther north. The front
will slowly edge northward tonight and Monday as the next upper
level trough digs into Nevada. This will result in a resumption of
southerly winds at 5 to 10 kts late tonight across much of southwest
Kansas. Lows will be mainly in the 60s to lower 70s. By Monday
afternoon, thunderstorms will develop along the stalled out front
in northern Kansas where low level moisture will be converging.
Thunderstorms may also develop farther south into western Kansas
ahead of a weak dryline. The best chance of severe storms with
large hail will be well north of Interstate 70 where surface based
CAPE and vertical wind shear will be stronger. High temperatures
ought to be in the upper 90s to near 100F given mostly sunny skies
with south winds.
.LONG TERM...(Monday night through Sunday)
ISSUED AT 305 PM CDT SUN AUG 24 2014
An upper level trough will move from Nevada and into the
Intermountain West on Wednesday, then into the Central Plains on
Thursday, and will be slow to exit the Central Plains by Saturday
afternoon. New model runs have this upper system slowing down its
progress and this will allow for thunderstorm chances Tuesday into
Saturday, with the best chances from Tuesday night into Thursday
with a cold front. The storms may linger near to east of Dodge City
on Saturday as the upper wave moves eastward. Severe storm chances
do not look all that favorable with fairly weak upper level wind
fields.
Daytime highs will be warm and in the mid to upper 90s ahead of the
front on Tuesday, then in the low to mid 90s on Wednesday, cooling
into the 80s for Thursday and Friday. Highs warm back up to around
90 for the Weekend. Overnight lows around 70 on Monday night and
Tuesday night cool into the 60s into the Weekend.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 1205 AM CDT MON AUG 25 2014
A weak surface boundary will lift north across western Kansas
overnight. As this boundary moves into west central and north
central Kansas the surface winds will become south southeast at
around 10 knots by 12z Monday. Based on 03z verification from the
NAM and HRRR will stay close to these models on timing of the wind
shift overnight. Southerly winds will increase to around 15 knots
by the early afternoon. BUFR soundings indicating VRF conditions
will prevail overnight and Monday as moisture around the 700mb
level improves during the Day on Monday. Late day instability and
forcing across north central Kansas may also give rise to some
scattered evening convection but given the scatters nature of the
storms late Monday will not include mention of thunderstorms yet
in the Hays 06z tafs.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 69 96 69 92 / 20 30 30 30
GCK 67 94 67 88 / 30 30 40 30
EHA 67 93 66 87 / 20 40 30 30
LBL 69 95 68 89 / 20 30 30 30
HYS 68 94 69 90 / 30 40 40 30
P28 73 98 74 95 / 10 20 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Finch
LONG TERM...Kruse
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
536 AM EDT MON AUG 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EDT MON AUG 25 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS LOOKING
SHORTWAVE LIFTING THRU ND INTO MANITOBA. ASSOCIATED SFC LOW WAS
MOVING INTO SE MANITOBA WITH COLD FRONT EXTENDING THRU FAR ERN MN.
AS EXPECTED...SCT TSTMS DEVELOPED AHEAD OF FRONT IN MN LATE
YESTERDAY AFTN/EVENING. STORMS THEN ORGANIZED INTO A LINE AND PUSHED
E INTO WI/UPPER MI. AS OF 09Z...SHRA/TSTMS EXTENDED FROM NCNTRL LAKE
SUPERIOR TO THE HURON MTNS AND CRYSTAL FALLS. CONVECTION HAS HELD
TOGETHER FOR MUCH OF THE NIGHT...AND IT HAS ONLY BEEN IN THE LAST HR
OR TWO THAT A NOTABLE DIMINISHING TREND HAS BEGUN. NSSL WRF RUN FROM
00Z/24 AUG DID A GREAT JOB AND BETTER THAN ANY OTHER MODEL IN
CAPTURING WHAT OCCURRED LAST NIGHT INTO EARLY THIS MORNING...
INCLUDING THE DIMINISHING TREND NOW UNDERWAY.
WHILE THERE IS STILL SOME INCREASE IN INSTABILITY AHEAD OF
CONVECTION PER SPC MESOANALYSIS OF 3HR ML/MUCAPE CHANGE...OVERALL
MAGNITUDE OF INSTABILITY IS NOTABLY LESS THAN WHAT WAS SUPPORTING
THE CONVECTION EARLIER IN THE NIGHT. DIMINISHING INSTABILITY
COMBINED WITH WEAKENING LOW-LEVEL JET WILL CONTINUE TO CAUSE
SHRA/TSRA TO WEAKEN AS THEY PUSH E THIS MORNING. QUESTION THEN
BECOMES WHETHER THERE WILL BE REDEVELOPMENT ALONG THE MOISTURE AXIS
THAT WILL BE SLOWING DOWN. NSSL WRF INCLUDING THE NCEP ARW/NMM WHICH
ALSO DID WELL WITH CONVECTION LAST NIGHT SUGGEST LITTLE OR NO
ADDITIONAL DEVELOPMENT THIS AFTN. WILL BASICALLY FOLLOW THAT
SCENARIO GIVEN A LACK OF MUCH FORCING THIS AFTN. WITH INCREASING
SUNSHINE AND 850MB THERMAL RIDGE OVER THE AREA...TODAY SHOULD BE THE
WARMEST DAY OF THE WEEK. FCST SOUNDINGS SUPPORT MAX TEMPS AS HIGH AS
THE MID/UPPER 80S OVER ROUGHLY THE W HALF. COULD BE WARMER DEPENDING
ON HOW QUICKLY CLOUDS SCATTER OUT. E WILL BE COOLER WITH MORE CLOUD
COVER AND CONTINUED SOUTHERLY FLOW OFF LAKE MICHIGAN.
LOOKS LIKE A SECONDARY COLD FRONT/TROF WILL SWEEP ACROSS THE AREA
LATER THIS AFTN/EVENING. AS THE TROF MOVES INTO THE ERN FCST AREA
THIS EVENING WHERE MOISTURE/INSTABILITY LINGER...ISOLD SHRA AND
PERHAPS A TSRA MAY DEVELOP FROM ERN LAKE SUPERIOR INTO ERN UPPER MI.
OTHERWISE...EXPECT A DRY NIGHT...BECOMING COOLER AND LESS HUMID.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 403 AM EDT MON AUG 25 2014
A FAIRLY QUIET AND GENERALLY DRY LONG TERM PERIOD IS IN STORE FOR
THE UPPER GREAT LAKES REGION FOR TUESDAY THROUGH THE WEEKEND. THIS
TRANSITION WILL OCCUR AS A RESULT OF THE LOW PRESSURE SYSTEM MOVING
THROUGH NORTHERN ONTARIO TODAY AND THE ASSOCIATED COLD FRONT THAT
PASSES THROUGH. BEHIND THIS LOW AND ASSOCIATED SHORTWAVE...HIGH
PRESSURE FROM THE EASTERN DAKOTAS WILL SHIFT EAST OVER THE UPPER
GREAT LAKES REGION BY WEDNESDAY WHILE A WEAK UPPER TROUGH SWEEPS
THROUGH. IN GENERAL...EXPECT THIS HIGH PRESSURE RIDGE TO SUPPRESS
ANY PRECIPITATION TO THE SOUTH OF THE AREA THROUGH THURSDAY. THERE
ARE A COUPLE MINOR ITEMS TO NOTE. FIRST...THE SECONDARY SHORTWAVE
MOVING THROUGH THE FLOW LATE TUESDAY NIGHT INTO WEDNESDAY MORNING
COULD TRY TO SPARK AN ISOLATED SHOWER BUT FEEL THE DRY AIR IN THE
LOWER LEVELS ASSOCIATED WITH THE HIGH PRESSURE RIDGE WILL INHIBIT
ANY RAIN FROM REACHING THE SURFACE. THUS...WILL JUST SHOW PASSING
MID CLOUDS AS THAT WAVE MOVES THROUGH. THE OTHER ITEM IS THE MUCH
COOLER AIR BELOW 850MB THAT WILL BE SURGING INTO THE CWA LATE
TONIGHT INTO TUESDAY. THIS WILL SETUP A RETURN TO ANOTHER COOLER
PERIOD OF HIGH TEMPERATURES OVER THE CWA. WITH THE COLD AIR JUST
STARTING TO MOVE IN ON TUESDAY...HIGHS OVER THE CENTRAL/EAST WILL
STILL RISE INTO THE UPPER 60S AND LOWER 70S WHILE AREAS OVER THE
WEST NEAR LAKE SUPERIOR WILL STAY IN THE MID 60S WITH THE
GUSTY WESTERLY WIND OFF THE LAKE. WEDNESDAY WILL BE THE COOLEST DAY
(AIDED BY THE MORNING MID CLOUDS LIMITING HEATING AND MODEL AVERAGE
850MB TEMPS AROUND 6-7C)...WITH HIGHS IN THE 60S OVER MOST OF THE
CWA. 850MB TEMPS WILL REBOUND SLIGHTLY ON THURSDAY AND ALLOW HIGHS
TO BE IN THE UPPER 60S TO AROUND 70 DEGREES. ALONG WITH THAT COOLER
AIR ON TUESDAY MORNING...SOME OF THE MODELS ARE INDICATING ENOUGH
MOISTURE FOR SOME CLOUDS OVER THE NORTH HALF OF THE CWA. THINK THE
COVERAGE WILL BE THE GREATEST DURING THE AFTERNOON HOURS WHEN THE
DIURNAL HEATING IS MAXIMIZED AND WILL SHOW PARTLY CLOUDY SKIES
DURING THAT TIME. EXPECT MOSTLY CLEAR SKIES FOR THE REST OF THE
MIDDLE OF THE WORK WEEK.
THE FOCUS THURSDAY NIGHT INTO THE WEEKEND WILL BE THE UPPER
DISTURBANCE MOVING OUT OF THE CENTRAL ROCKIES AND INTO THE CENTRAL
PLAINS ON WEDNESDAY. THE INITIAL PORTION OF THIS WAVE WILL SHIFT
NORTHEAST TOWARDS THE UPPER GREAT LAKES REGION THURSDAY NIGHT AND
FRIDAY...WITH MODELS STILL VARYING ON THE NORTHWARD EXTENT OF THE
WAVE AND ASSOCIATED PRECIP. CURRENT CONSENSUS IS FOR IT TO BRUSH
THE SOUTHEAST THIRD OF THE CWA AND WILL SHOW SLIGHT CHANCES IN THAT
AREA. THE SECOND WAVE WILL PUSH THROUGH THE AREA FRIDAY NIGHT INTO
SATURDAY AND BRING ANOTHER OPPORTUNITY FOR PRECIPITATION. MODELS
ALSO VARYING ON THE LOCATION THIS WAVE...SO WILL FOLLOW A BLEND OF
GEM/GFS/ECMWF FOR POPS (SLIGHT OR LOW END CHANCES) WITH THE BEST
CHANCES OVER THE SOUTHEAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 140 AM EDT MON AUG 25 2014
AN APPROACHING COLD FRONT OVERNIGHT WILL BRING SCT/NMRS SHRA/TSRA
INTO UPPER MI. THE BEST CHANCE FOR TSRA WILL BE ACROSS THE WEST AT
IWD/CMX WHILE FARTHER EAST AT SAW...LESS FAVORABLE INSTABILITY WILL
LIMIT TS CHANCES. PLENTY OF MOISTURE WILL REMAIN WITH UPSLOPE
CONDITIONS BRINGING ANOTHER ROUND OF MAINLY MVFR CEILINGS TO SAW LATE
IN THE NIGHT THAT SHOULD DROP TO IFR TOWARD SUNRISE. OTHERWISE...
LOOK FOR SLOWLY IMPROVING CONDITIONS W TO E TODAY AS DRIER AIR WORKS
IN FROM THE W BEHIND THE EXITING COLD FRONT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EDT MON AUG 25 2014
FOG MAY BE AN ISSUE OVER PORTIONS OF LAKE SUPERIOR THRU THIS
EVENING...MAINLY CNTRL/E AND ESPECIALLY NE GIVEN THE HUMID AIR MASS
AND PCPN THAT HAS OCCURRED. PASSAGE OF COLD FRONT AND ARRIVAL OF
DRIER AIR TODAY/THIS EVENING WILL THEN WORK TO CLEAR OUT THE FOG
FROM W TO E. BEHIND FRONT...WESTERLY WINDS WILL INCREASE TO
15-25KT OVER WRN LAKE SUPERIOR THIS AFTN AND THEN OVER CNTRL LAKE
SUPERIOR THIS EVENING. THESE STRONGER WINDS WILL LINGER INTO TUE
MORNING...THEN WINDS WILL DIMINISH AS HIGH PRES MOVES CLOSER TO THE
AREA. THE HIGH WILL SETTLE INTO THE UPPER LAKES TUE NIGHT THRU
THU...BRINGING A PERIOD OF LIGHTER WINDS MOSTLY UNDER 15KT. THE
LIGHTER WINDS WILL LINGER INTO FRI DESPITE THE HIGH MOVING TO THE E.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
325 AM EDT MON AUG 25 2014
LATEST UPDATE...
SYNOPSIS/SHORT TERM/LONG TERM/MARINE
.SYNOPSIS...
ISSUED AT 325 AM EDT MON AUG 25 2014
WARM AND HUMID CONDITIONS WILL CONTINUE TODAY THROUGH TUESDAY WITH
SCATTERED SHOWERS AND THUNDERSTORMS. THUNDERSTORMS THIS AFTERNOON
THROUGH TUESDAY MAY CONTAIN LOCALLY HEAVY RAINFALL. DRY AND COOLER
WEATHER WILL BRIEFLY RETURN WEDNESDAY FOLLOWED BY WARMER AND MORE
HUMID WEATHER WITH ANOTHER CHANCE OF SHOWERS AND STORMS LATE IN
THE WEEK.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 325 AM EDT MON AUG 25 2014
IT WILL BE VERY WARM AND HUMID TODAY WITH MAX TEMPS REACHING WELL
INTO THE 80S AND DEW POINT VALUES UP INTO THE UPPER 60S TO LOWER
70S. SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP LATER TODAY
AS INSTABILITY BUILDS AND SB CAPE VALUES POTENTIALLY REACH AROUND
2000-2500 J/KG NEAR TO EAST OF US-131 THIS AFTERNOON.
SEVERE WX IS UNLIKELY MAINLY DUE TO WEAK DEEP LAYER SHEAR BUT AN
ISOLATED SEVERE STORM CANNOT BE RULED OUT THIS AFTERNOON AND EARLY
EVENING WHEN INSTABILITY WILL BE MAXIMIZED. ANY STORMS THAT DO
DEVELOP COULD PRODUCE LOCALLY RAINFALL WITH PRECIPITABLE WATER
VALUES UP IN THE 1.75 TO 2 INCH RANGE TODAY.
SCATTERED SHOWERS AND PERHAPS A FEW STORMS WILL CONTINUE INTO THIS
EVENING. THEN THE COLD FRONT WILL BRING SCATTERED SHOWERS AND
THUNDERSTORMS ON TUESDAY. THE BEST CHANCE FOR A FEW STRONG TO
POTENTIALLY SEVERE STORMS TUESDAY WOULD BE IN THE AFTERNOON OVER OUR
SE FCST AREA WHEN SB CAPE VALUES WILL POTENTIALLY REACH AROUND 3000
J/KG.
IT HAS BEEN NOTED THAT OVERALL SHORT TO MEDIUM RANGE GUIDANCE
TRENDS ARE BRINGING THE COLD FRONT THROUGH FASTER. THEREFORE WE
HAVE TRIMMED BACK POPS SIGNIFICANTLY FOR TUESDAY NIGHT AND ARE
KEEPING LINGERING LOW POPS CONFINED TO OUR SOUTHERN FORECAST AREA.
DRY WEATHER IS NOW ANTICIPATED WEDNESDAY WITH THE HIGH PRESSURE RIDGE
IN PLACE OVER THE NORTHERN GREAT LAKES REGION.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 325 AM EDT MON AUG 25 2014
THE LAST COUPLE NIGHTS HAVE SEEN THE GFS GUIDANCE TREND TOWARDS THE
ECMWF IN TERMS OF THE EVOLUTION OF THE PATTERN. TONIGHT...HAVE
THEREFORE FOLLOWED THE LEAD OF THE ECMWF THROUGH THE LONG TERM
FORECAST.
THE LONG TERM LOOKS TO FEATURE A DECENT ABOUT OF RAINFALL WITH A
BOUNDARY OSCILLATING THROUGH THE REGION AND NEAR NORMAL TEMPERATURES.
AS FOR THE DETAILS...THE PERIOD LOOKS TO START OFF DRY WITH SURFACE
HIGH PRESSURE SAGGING INTO THE AREA FROM THE NORTH WEDNESDAY NIGHT.
FEEL THURSDAY WILL LIKELY BE DRY AS WELL...BUT BLENDED IN WITH
NEIGHBORING OFFICES AND HAVE A 20 PCT CHANCE FOR SHOWERS/STORMS IN
THE FAR WEST.
CHANCES FOR SHOWERS AND STORMS THEN LOOK TO BE POSSIBLE IN THE
REMAINDER OF THE FORECAST PERIOD...THURSDAY NIGHT THROUGH SUNDAY.
MOISTURE COMES SURGING BACK IN THURSDAY NIGHT ESPECIALLY ALOFT. THE
ECMWF HAS A WARM FRONT OR A STATIONARY BOUNDARY NEARBY FRI-SUN. HAVE
CHANCE POPS ESSENTIALLY BLANKETED THROUGHOUT THIS PERIOD OF THE
FORECAST. THE DAYS 4-5 AND 6-7 QPF PROGS FROM WPC ALSO BEAR THIS
OUT. THEY SHOW RAINFALL TOTALS AROUND AN INCH FOR MOST AREAS...WHICH
SEEMS REASONABLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1120 PM EDT SUN AUG 24 2014
IT WOULD SEEM FOG IS BECOMING LESS LIKELY OVERNIGHT. AS I WROTE
FOR THE 00Z TAF SET...THE WINDS IN THE BOUNDARY LAYER OF BETWEEN
15 AND 25 KNOTS ARE ENOUGH TO KEEP SURFACE FOG FROM BECOMING MUCH
OF AN ISSUE TONIGHT. INSTEAD THE IR-FOG LOOP SHOWS PATCHY LOW CLOUDS
(MVFR CIGS) DEVELOPING NEAR AND SOUTH OF I-96. AS THE AIR
CONTINUES TO COOL OVERNIGHT THE LOW CLOUDS SHOULD BECOME MORE
EXTENSIVE AND CIGS SHOULD LOWER SOME. SO I HAVE ONLY MVFR CIGS/VSBY
AT ALL TAF SITES.
THE CONVECTION FOR MONDAY STILL SEEMS POSSIBLE. THE LATEST VERSION
OF THE RAP MODEL AND THE NAM12 SHOW LATE MORNING AND AFTERNOON
CONVECTION. SO...I NOW HAVE VCTS AFTER 15Z FOR THAT. I WOULD
EXPECT ONCE THE SUN SETS MONDAY EVENING THE CONVECTION WILL BE
DONE. THERE SHOULD BE ENOUGH WIND TOMORROW NIGHT TO KEEP FOG FROM
BECOMING AN ISSUE.
&&
.MARINE...
ISSUED AT 325 AM EDT MON AUG 25 2014
MINIMAL WIND AND WAVE ACTION IS ANTICIPATED TODAY THROUGH TONIGHT
INTO TUESDAY. HOWEVER PATCHY FOG WILL POSE A HAZARD TO MARINERS.
&&
.HYDROLOGY...
ISSUED AT 1104 AM EDT SUN AUG 24 2014
BEST CHANCE FOR SIGNIFICANT RAINFALL WOULD BE MONDAY NIGHT THROUGH
WEDNESDAY WITH A SLOW MOVING COLD FRONT. THIS IS NOT A GUARANTEE
AS THE LLJ IS FORECAST TO BE QUITE WEAK. NEVERTHELESS...A VERY
MOIST ATMOSPHERE COMBINED WITH FORCING VIA THE COLD FRONT AND SLOW
CELL MOVEMENT COULD RESULT IN SOME SIGNIFICANT RAINFALL IF STORMS
DEVELOP OVER OUR AREA. PW VALUES WILL LIKELY BE AROUND 1.75"
MONDAY NIGHT AND TUESDAY. MODEL GUIDANCE IS MIXED REGARDING HOW
LONG THE FRONT MAY HANG UP...SO IT IS UNCLEAR WHEN THE THREAT FOR
SIGNIFICANT RAINFALL WOULD END.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...DUKE
AVIATION...WDM
HYDROLOGY...HOVING
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
150 AM EDT MON AUG 25 2014
.SYNOPSIS...
HIGH PRESSURE WILL EXPAND SOUTH ACROSS THE AREA OVERNIGHT AND
WEDNESDAY...BRINGING COOL AND DRY WEATHER. TROPICAL STORM
CRISTOBAL MAY BECOME A HURRICANE IN THE NEXT FEW DAYS AS IT PASSES
SEVERAL HUNDRED MILES EAST OF THE CAROLINAS. A WARMING TREND WILL
DEVELOP LATE IN THE WEEK. A BACKDOOR FRONT MAY APPROACH BY NEXT
WEEKEND...BRINGING A RISK FOR SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1:50 AM MONDAY...MOST PLACES WILL REMAIN CLEAR
OVERNIGHT...WITH SOME PATCHES OF STRATO-CU ALONG THE COAST.
TEMPERATURES NOW DOWN INTO THE 60S MOST LOCATIONS. NO CHANGES TO
THE FORECAST WITH THE LATEST UPDATE. PREVIOUS DISCUSSIONS FOLLOW:
ASIDE FROM A FEW PATCHES OF STRATOCUMULUS NEAR THE BEACHES SKIES
ARE CLEAR AND SHOULD REMAIN MOSTLY CLEAR OVERNIGHT. THE 00Z MHX
SOUNDING SHOWED A CLEAR SUBSIDENCE INVERSION AT 5300 FEET AGL AND
MATCHED 18Z MODEL PROJECTIONS CLOSELY. THE ONLY CHANGE WITH THIS
UPDATE WAS TO LOWER DEWPOINT FORECASTS BY A FEW DEGREES THROUGH
THE NIGHT BASED ON CURRENT OBS AND THE 00Z MHX SOUNDING. PREVIOUS
DISCUSSION FROM 730 PM FOLLOWS...
AN EXTENSIVE STRATOCUMULUS DECK INLAND IS BEGINNING TO DECAY NOW
THAT THE SUN IS SETTING. SKIES SHOULD BECOME GENERALLY CLEAR
OVERNIGHT AS DRIER AIR ARRIVES IN THE 850 MB LAYER NEAR THE TOP OF
TODAY`S SURFACE MIXED LAYER. BESIDES DOWNWARD ADJUSTMENTS TO SKY
COVER...NO SIGNIFICANT CHANGES HAVE BEEN MADE TO THE FORECAST.
PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
COOL BUT BEAUTIFUL LATE SUMMER AFTERNOON COMING TO AN END...LEAVING
WHAT WILL BE ONE OF THE COOLER NIGHTS THIS AREA HAS SEEN IN QUITE
SOME TIME.
COLD FRONT CONTINUES TO SAG WELL SOUTH OF THE AREA...AND HAS PUSHED
TO NEARLY THE FLORIDA STATE LINE TODAY. DRIVING THIS BOUNDARY IS A
STRONG RIDGE OF HIGH PRESSURE OF CANADIAN ORIGIN...WITH THE CENTER
OF THIS HIGH ACTUALLY WELL NORTH OF WINNIPEG, CANADA IN THE NORTH
CENTRAL PART OF THE COUNTRY. THIS HIGH IS RIDGING INTO NEW ENGLAND
AND THEN DOWN THE EASTERN SEABOARD...WITH ABNORMALLY COOL AND DRY
AIR FOR LATE AUGUST FILTERING INTO THE REGION. THIS AIR MASS IS VERY
FALL-LIKE...AND DEWPOINTS HAVE FALLEN INTO THE LOW AND MID 60S
AREA-WIDE TODAY. THIS DRY AIR HAS LIMITED TOTAL INSTABILITY...AND
ALTHOUGH HIGH-RES GUIDANCE CONTINUES TO SUGGEST THE POTENTIAL FOR
ISOLATED SEA-BREEZE SHOWERS THROUGH THIS EVE...THE CHANCE FOR THAT
IS WANING...AND EVEN DIURNAL CU IS HAVING TROUBLE GAINING MUCH
AGITATION. STILL CONTINUED JUST VERY SCHC ALONG THE SC PORTION OF
THE SEA BREEZE FOR THE NEXT FEW HOURS. IF A SHOWER DOES DEVELOP IT
WILL ERODE QUICKLY AFTER DARK...AS WILL THE MAJORITY OF THE CLOUD
COVER.
NE WINDS WILL REMAIN ELEVATED TONIGHT...LIKELY STAYING 5-10 MPH INTO
MONDAY MORNING. THESE WINDS WILL CONTINUE TO ADVECT COOL/DRY
AIR...THUS DRIVING MINS WELL BELOW 70...WITH LOWER 60S ENCOMPASSING
THE NORTHERN HALF OR 2/3 OF THE CWA. WHILE ELEVATED WINDS TEND TO
LIMIT OVERALL COOLING...NE WINDS HAVE A TENDENCY TO COOL THE AREA
MORE THAN WOULD TYPICALLY BE EXPECTED...ESPECIALLY ACROSS THE CAPE
FEAR REGION. FOR THIS REASON HAVE FORECAST THE LOWEST TEMPS IN THE
NE ZONES TONIGHT...AND WILMINGTON MAY SEE ITS COOLEST NIGHT SINCE
EARLY JUNE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...THE FORECAST AREA WILL REMAIN IN THE GRIP OF
AN UNSEASONABLE NE FLOW AS HIGH PRESSURE CENTERED ACROSS THE
NORTHEAST U.S. RIDGES SOUTH...WITH ITS AXIS REMAINING TO THE WEST OF
OUR FORECAST AREA. AT THE SAME TIME...SLOW STRENGTHENING OF THE VERY
SLOW MOVING TROPICAL STORM ACROSS THE BAHAMAS IS EXPECTED. THIS WILL
SERVE TO PROLONG THE RATHER TIGHT PRESSURE GRADIENT BETWEEN THESE
TWO SYSTEMS.
AS THESE NE WINDS PERSIST...THEY WILL SERVE TO PILE UP WATER ON THE
IMMEDIATE COAST. THIS IN COMBINATION WITH THE NEW MOON WILL INCREASE
THE RISK FOR MINOR BEACH EROSION FOR THOSE BEACHES EXPOSED TO A NE
FETCH AND MINOR COASTAL FLOODING DURING THE NIGHTTIME HIGH TIDE...
BOTH AT THE BEACHES AND ALONG THE LOWER CAPE FEAR RIVER. OTHER
HAZARDS WILL INCLUDE A STRONG LONG SHORE CURRENT...MODERATE TO
PERHAPS STRONG RIP CURRENTS AND HIGHER THAN NORMAL...ROUGH SURF.
TEMPS WILL BE COOL IN THIS BREEZY NE FLOW REGIME. HIGHS WILL BE
IN THE LOWER TO MID 80S...WITH TUE PERHAPS SLIGHTLY COOLER THAN
MON. LOWS WILL BE IN THE LOWER TO MID 60S WITH PERHAPS UPPER 60S
AT THE BEACHES. WIND SPEEDS ON MON WILL BE UP TO 10 TO 20 MPH WITH
HIGHER GUSTS...ESPECIALLY AT THE BEACHES.
OFFSHORE SHOWERS ARE EXPECTED TO REMAIN THERE FOR MUCH OF THE
PERIOD. TRAJECTORIES WILL AT TIMES BRING THE SHOWERS VERY NEAR THE
BEACHES...BUT GIVEN THE DRYNESS OF THE COLUMN...EXPECT THESE SHOWERS
TO LARGELY ERODE BEFORE MOVING ONSHORE.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...THE MID LEVEL PATTERN WILL SHOW TYPICAL LATE
SUMMER LETHARGY THROUGH THE PERIOD AS RIDGING WILL BE THE CENTRAL
THEME.
THE AXIS OF THE RIDGE MOVES FROM THE MISSISSIPPI VALLEY TO OFF THE
PENINSULA OF FLORIDA BY THE END OF THE PERIOD. AT THE SURFACE...WEAK
HIGH PRESSURE WILL PREVAIL AS WELL AND AS THE MID LEVEL RIDGE
REPOSITIONS...A RELATIVELY WEAK BACKDOOR FRONT WILL MOVE ACROSS
FRIDAY. THIS WILL SERVE TO ENHANCE THE POPS BOTH FRIDAY AND
SATURDAY. HOWEVER MOISTURE AND FORCING REMAIN RELATIVELY WEAK AND
SLIGHT CHANCE FRIDAY TO LOW CHANCE SATURDAY WILL SUFFICE FOR NOW.
THERE IS ALSO SLIGHT CHANCE POPS FOR WEDNESDAY AND THURSDAY ALONG
THE COASTAL AREAS.
THE COOL REFRESHING AIRMASS WILL BE A THING OF THE PAST AS
TEMPERATURES WEDNESDAY THROUGH FRIDAY WILL BE AT OR JUST ABOVE
CLIMATOLOGY. FOR NEXT WEEKEND...A SLIGHT DROP IN TEMPERATURES IS
SEEN AS THE BACKDOOR FRONT MOVES ACROSS BUT JUST A COUPLE OF
DEGREES.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...VFR WILL PREVAIL THROUGH THIS TAF PERIOD. OTHER THAN
THE POSSIBILITY OF SOME MVFR STRATOCU CLIPPING THE COASTAL TERMS
EARLY THIS MORNING...MOSTLY CLEAR CONDITIONS WILL PERSIST THROUGH
THE OVERNIGHT HOURS. SREF PROBABILITIES CONTINUE TO DEPICT THE
MVFR CIGS STAYING WELL OFFSHORE...SO NO MENTION OF REDUCED CIGS IN
THE TAFS. NORTHEAST WINDS AROUND 10 KT WILL STRENGTHEN TO 10-15 KT
WITH GUSTS UP TO 20 KT AS HIGH PRESSURE CONTINUES WEDGING INTO THE
CAROLINAS TODAY. LOW LEVEL MOISTURE WILL REMAIN TRAPPED BENEATH
THE SUBSIDENCE INVERSION...SO EXPECT SCT 3-7KFT CU TO DEVELOP
AGAIN DURING THE DAY. BUT WITH EXTREMELY DRY AIR IN PLACE ABOVE
700 MB...THERE IS NO PCPN IN THE FORECAST THROUGH THE END OF THE
PERIOD.
EXTENDED OUTLOOK...EXPECT VFR CONDITIONS THROUGH THE EXTENDED
PERIOD. SLIGHT CHANCE OF SHOWERS FOR OUR NORTHERN TERMINALS FRI.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1:30 AM MONDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSIONS FOLLOW:
WIND SPEEDS ARE RUNNING JUST A BIT HIGHER THAN FORECAST NEARSHORE
BUT LOOK GOOD OFFSHORE COMPARED TO BUOYS 41037 AND 41004. MARINE MOS
GUIDANCE AND LATEST RUC AND HRRR MODELS SUGGEST WIND SPEEDS WILL
BACK MORE NORTHERLY OVERNIGHT BUT WILL NOT DECREASE MUCH IN SPEED.
IN FACT THE ADVECTION OF COOLER AIR OVER THE VERY WARM OCEAN SURFACE
LATER TONIGHT WILL PROBABLY ENHANCE GUSTINESS AND DOWNWARD TRANSPORT
OF STRONGER WINDS FROM ALOFT. NO SIGNIFICANT CHANGES WERE MADE TO
THE FORECAST OVERNIGHT. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...
PINCHING NE GRADIENT EAST OF A RIDGE OF HIGH PRESSURE EXPANDING DOWN
THE COAST IS CAUSING DETERIORATING MARINE CONDITIONS TODAY. WINDS
ARE SLOWLY BUT STEADILY RISING OUT OF THE NE...WITH SPEEDS OF 15-20
KTS COMMON ACROSS THE WATERS...WITH SOME GUSTS APPROACHING 30 KTS
DEVELOPING OVER THE NORTHERN WATERS AND OUTSIDE OF 20 NM. AS THE
HIGH PRESSURE STRENGTHENS TONIGHT...THE GRADIENT WILL TIGHTEN
FURTHER...AIDED BY THE DISTANT BUT STRENGTHENING TROPICAL STORM
CRISTOBAL NEAR THE BAHAMAS. THIS WILL CAUSE WIDESPREAD 15-25 KT NE
WINDS THROUGH THE PERIOD...WITH SEAS BUILDING TO 5-8 FT.
WAVE HEIGHTS WILL BE DRIVEN ALMOST ENTIRELY BY A NE WIND CHOP
TONIGHT. HOWEVER...LONGER PERIOD SWELL ASSOCIATED WITH TROPICAL
STORM CRISTOBAL IS FORECAST TO BEGIN TO ENTER THE SPECTRUM TONIGHT.
ONLY NOTICEABLE LONG-SWELL PRESENTLY EXISTS AT 41004 /EDISTO BUOY/
WHICH IS OBSERVING A LOW-AMPLITUDE 13 SEC SWELL. EXPECT THIS TO
GRADUALLY LIFT NE INTO THE LOCAL WATERS...BUT HAVE ONLY MINIMAL
CONTRIBUTION TO THE SIGNIFICANT SEAS UNTIL MONDAY.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...THE PRESSURE DIFFERENCE BETWEEN HIGH PRESSURE
TO THE NORTH AND A SLOWLY DEVELOPING TROPICAL STORM ACROSS THE
BAHAMAS WILL KEEP A TIGHT PRESSURE GRADIENT ACROSS THE WATERS. A
SMALL CRAFT ADVISORY REMAINS IN EFFECT. WINDS WILL COMMONLY BE
SUSTAINED AT 20 TO 25 KT. THE LONG NE FETCH WILL KEEP SEAS IN THE 4
TO 7 FT RANGE WITH AT LEAST 8 FT SEAS BEYOND 20 NM. A 10 TO 12
SECOND SE SWELL IS EXPECTED TO SLOWLY BUILD THROUGH THE PERIOD.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...CONFIDENCE CONTINUES TO BUILD THAT THE ONLY
IMPACTS FROM CRISTOBAL WILL BE THE SWELL COMPONENT ADDED TO THE WAVE
SPECTRUM. THE LATEST WAVEWATCH HURRICANE BULLETIN FOR FRYING PAN
SHOALS SHOWS 7-8 FEET DEVELOPING OR PERSISTING WEDNESDAY THROUGH
EARLY THURSDAY WITH A GOOD PORTION OF THIS BEING THE WIND WAVE
COMPONENT. THIS MAKES SENSE AS THE GFS IS NOT DEVELOPING THE SYSTEM
APPRECIABLY. FOR THE 0-20 MILE COASTAL WATERS 4-6 FEET WEDNESDAY AND
EARLY THURSDAY SHOULD SUFFICE. BY FRIDAY A WEAK PRESSURE PATTERN
YIELDS LIGHT WINDS AND SEAS. FOR THE WINDS WEDNESDAY AND
THURSDAY...A NORTHEASTERLY FLOW OF 10-15 KNOTS WEDNESDAY DROPS TO
SINGLE DIGITS THURSDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR AMZ250-252-254-
256.
&&
$$
SYNOPSIS...RJD
NEAR TERM...REK/TRA/JDW
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...REK/BJR
MARINE...REK/RJD/TRA/JDW/SHK
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1209 AM CDT MON AUG 25 2014
.UPDATE... /ISSUED 902 PM CDT SUN AUG 24 2014/
SKIES ARE MOSTLY CLEAR OVER MUCH OF THE FORECAST AREA THIS
EVENING WITH TEMPERATURES RANGING FROM THE LOWER 70S TO MID 80S.
ALL OF THE THUNDERSTORM ACTIVITY THAT WAS OVER THE FORECAST AREA
EARLIER THIS EVENING HAS ENDED AND NO ADDITIONAL THUNDERSTORMS ARE
EXPECTED FOR THE REMAINDER OF TONIGHT. WILL UPDATE FORECAST TO
REMOVE ANY MENTION OF RAIN TONIGHT.
ARS
&&
.DISCUSSION... /ISSUED 615 PM CDT SUN AUG 24 2014/
NQA RADAR BACK IN SERVICE AND JUST IN TIME TO SHOW CONVECTION
DEVELOPING IN NORTH MISSISSIPPI. TEMPERATURES WERE MAINLY IN THE
90S ACROSS THE MIDSOUTH WITH A RECORD 100 DEGREES...THE WARMEST
READING SINCE AUGUST 2012...AT THE MEMPHIS INTERNATIONAL AIRPORT.
FOR THE REMAINDER OF TODAY AND TONIGHT...SHORT TERM HRRR MODEL
SHOWING CONVECTION BECOMING SCATTERED BY 4 PM FOR POINTS ALONG
AND WEST OF THE MISSISSIPPI RIVER...WHICH CURRENTLY LINES UP WITH
PW`S ABOVE 1.80 INCHES. COULDN`T RULE OUT AN ISOLATED WET
MICROBURST WITH THE STRONGEST STORMS. ACTIVITY WILL WANE BY 9 PM
LEAVING SKIES PARTLY CLOUDY OVERNIGHT. THIS SHOULD HELP KEEP MORE
HEAT IN...WITH OVERNIGHT LOWS AGAIN IN THE MID AND UPPER 70S.
MONDAY AND TUESDAY...A WEAK DISTURBANCE WILL MOVE WESTWARD ALONG
THE GULF COAST/SOUTHSIDE OF THE UPPER RIDGE...AND AS IT DOES
EASTERLY WINDS IN THE BOUNDARY LAYER AND MIDLEVELS WILL SLIDE
DRIER AIR OFF THE APPALACHIANS IN ITS WAKE. HEAT INDICES WILL
CONTINUE TO FLIRT WITH 105F TOMORROW...DESPITE MORE CLOUD COVER
AND CONVECTION. FEEL BY TUESDAY ENOUGH DRY AIR WILL HAVE
OVERSPREAD THE MIDSOUTH TO REDUCE HEAT INDICES BELOW 105F.
ISOLATED STORMS WILL BE POSSIBLE ON TUESDAY BUT MAINLY WEST OF THE
MISSISSIPPI RIVER NEAR THE FRONT EDGE OF THE DRIER AIR.
WEDNESDAY THROUGH FRIDAY...MODELS ARE IN GOOD AGREEMENT THAT THE
UPPER RIDGE WILL REMAIN OVER THE REGION...BUT STRONGER SUBSIDENCE
WILL KEEP DEWPOINTS IN THE 60S AND LOWER RAIN CHANCES TO AROUND 10
PERCENT. TEMPERATURES WILL BE IN THE LOW TO MID 90S WITH AFTERNOON
HEAT INDICES IN THE 93-100F RANGE.
NEXT WEEKEND...THE GFS AND EURO ARE BECOMING BETTER ALIGNED THAT
THE RIDGE WILL FLATTEN IN RESPONSE TO AN APPROACHING CENTRAL
PLAINS SHORTWAVE. THIS DISTURBANCE NOW APPEARS SOMEWHAT WEAKER AND
OUT OF PHASE WITH THE MAIN UPPER LEVEL FLOW. NONETHELESS MOISTURE
OUT AHEAD OF THE SYSTEM WILL MOVE OVER THE OZARKS ON SATURDAY AND
INTO THE MIDSOUTH BY EARLY SUNDAY. HAVE BUMPED UP TEMPERATURES TO
MAINLY THE LOW 90S FOR HIGHS AND KEPT A CONSERVATIVE APPROACH TO
THE RAIN CHANCES.
JAB
&&
.AVIATION...
06Z TAF CYCLE
ISOLATED TO SCATTERED TSRA ARE EXPECTED TO DEVELOP MONDAY AFTERNOON
AROUND THE KMEM...KMKL...AND KTUP TAF SITES...MENTIONED VCTS FOR
THESE SITES. OTHERWISE VFR CONDITIONS WILL PREVAIL DURING THE
PERIOD...THE EXCEPTION POSSIBLY BEING MVFR CONDITIONS IN FOG AT KMKL
EARLY MONDAY MORNING. WINDS TONIGHT EASTERLY 5 KTS OR LESS. WINDS
MONDAY E-SE 4-6 KTS. WINDS MONDAY NIGHT E 5 KTS OR LESS.
JCL/KRM
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR DUNKLIN-PEMISCOT.
MS...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR ALCORN-BENTON MS-
CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-
MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...HEAT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BENTON TN-CARROLL-
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1133 PM CDT SUN AUG 24 2014
.AVIATION...
VFR CONDITIONS SHOULD PREVAIL FOR THE NEXT 24 HOURS. TSRA ACTIVITY
IS EXPECTED ACROSS THE AREA MONDAY AFTERNOON AND EVENING...BUT WILL MOST
LIKELY REMAIN WEST OF BOTH TERMINALS. LIGHT EASTERLY SURFACE WINDS
EARLY THIS MORNING SHOULD BECOME SOUTHERLY BUT REMAIN AROUND 12
KTS OR LESS DURING THE DAY.
&&
.PREV DISCUSSION... /ISSUED 725 PM CDT SUN AUG 24 2014/
UPDATE...
QUICK UPDATE TO ADJUST POP/WX/QPF GRIDS THROUGH THIS EVENING TO
BETTER CORRESPOND TO CURRENT RADAR TRENDS. MOST NOTABLY...
INCREASED POPS INTO THE CHANCE AND LIKELY CATEGORIES ACROSS A GOOD
PORTION OF THE ROLLING PLAINS WHERE A POORLY ORGANIZED CLUSTER OF
CONVECTION CONTINUES. WE EXPECT AN OVERALL DOWNWARD TREND IN THE
CONVECTION THROUGH THE MID/LATE EVENING HOURS AS THE UNSTABLY AND
DIURNALLY DRIVEN FORCING WANES.
PREV DISCUSSION... /ISSUED 636 PM CDT SUN AUG 24 2014/
AVIATION...
CURRENT RADAR TRENDS SUGGEST THAT KLBB AND KCDS MAY ESCAPE ANY
-TSRA IN THE NEXT HOUR OR SO...BUT THERE IS STILL AN OUTSIDE
CHANCE. ALSO...SOME GUSTY OUTFLOW WINDS ARE STILL POSSIBLE.
OTHERWISE...VFR CONDITIONS WITH SRLY SURFACE WINDS EXPECTED
THROUGH MID-AFTERNOON MONDAY.
PREV DISCUSSION... /ISSUED 343 PM CDT SUN AUG 24 2014/
SHORT TERM...
DESPITE OF A WESTWARD EXPANSION OF WEAK RIDGING ALOFT AND VERY
LITTLE IF ANY SURFACE FEATURES...AN ADEQUATE BOOST IN THETA-E EARLIER
TODAY SUPPLIED MUCH OF THE AREA WITH DEEPER MOISTURE NECESSARY FOR
SOME DIURNALLY DRIVEN TSTORMS. NON-HIGH RES MODELS HAVE LARGELY
MISSED THE BOAT SO FAR TODAY WITH THE EXPERIMENTAL MODELS PLAYING
THE ROLE OF THE DARK HORSE. RAP DATA SHOW THE RICHEST PWATS OF 1.3
INCHES CONFINED EAST OF A BROWNFIELD TO SILVERTON LINE WITH
GENERALLY ONE INCH OR LESS FARTHER WEST. ENVIRONMENT IN THE RICHER
PWATS IS CHARACTERIZED BY SBCAPES OF 1200-2500 J/KG WITH WEAK SHEAR.
THIS THEME WILL PERSIST THROUGH MID-EVENING AT WHICH POINT TSTORMS
WILL DWINDLE...BUT UNTIL THEN WE EXPECT ADDITIONAL STRONG TO PERHAPS
BRIEFLY SEVERE PULSE MODES WITH MICROBURSTS THE PRIMARY HAZARD.
BY MONDAY MORNING...DEEPER MONSOONAL MOISTURE WILL BE TUGGED NORTH
INTO NEW MEXICO AROUND THE ZONAL RIDGE AXIS STILL POISED FIRMLY OVER
THE SOUTH PLAINS. HEIGHT FIELDS ON THE WESTERN PERIPHERY OF THIS
RIDGE ARE NOT SHOWN TO BUILD ANY...SO THE OPPORTUNITY WILL EXIST FOR
ANOTHER ROUND OF SOLAR-POWERED TSTORMS MAINLY NEAR THE NM STATE LINE
WHERE OCCASIONAL DISTURBANCES ARE PROGGED TO LIFT NORTH FROM
CHIHUAHUA. OTHERWISE...WE CONTINUE TO SIDE WITH THE WARMER SPECTRUM
OF MOS GUIDANCE FOR BOTH LOWS AND HIGHS GIVEN THE RECENT OBSERVED
TRENDS.
LONG TERM...
COOLER WEATHER IS ON THE WAY AS WELL AS A SHOT FOR RAIN. BUT BEFORE
WE GET THERE...WARM AND DRY WEATHER WILL CONTINUE TO DOMINATE US AS
HIGH PRESSURE TO OUR EAST EXTENDS OVER THE REGION. OUR NORTHWESTERN
ZONES WILL HAVE A BIT OF A REPRIEVE MONDAY NIGHT AS A WEAKNESS
PROPAGATES AROUND THE WESTERN EDGE OF THE RIDGE. THE WEAKNESS MAKES
USE OF A SURFACE TROF LOCATED OVER THE SOUTHWESTERN TX PANHANDLE AND
FIRES SCATTERED CONVECTION IN THAT REGION. CHANCES ARE ONLY SLIGHT
AS THE AVAILABLE MONSOONAL MOISTURE ONLY COVERS A VERY SMALL AREA
WHICH COINCIDES WITH THE SURFACE TROF. BY TUESDAY AND INTO
WEDNESDAY...THE RIDGE TO OUR EAST BUILDS FURTHER WEST INHIBITING
CHANCES FOR ANY RAIN...HOWEVER A LOW AWAITS US OVER THE GREAT BASIN
AND IS READY TO MOVE IN AND DEFEAT THE EVIL RIDGE. WITH THE
EXCEPTION OF THE GFS...MODELS HAVE BEEN IN DECENT AGREEMENT WITH
HANDLING OF THE LOW THE PAST SEVERAL RUNS. THE 12Z RUN YIELDED THE
GFS SLOWING THE EASTWARD PROGRESSION OF THE LOW AND IS MORE IN LINE
WITH THE OTHER MODELS. THE LOW WILL INITIALLY START OFF CLOSED AS IT
MOVES ACROSS THE ROCKIES INTO THE CENTRAL PLAINS DURING WHICH TIME
IT WILL SLOWLY BECOME AN OPEN WAVE. BY LATE WEDNESDAY A COLD FRONT
SHOULD BE KNOCKING ON OUR DOOR. THE TIMING OF THE FRONT IS SOMEWHAT
IN QUESTION WITH TIMINGS RANGING FROM EARLY TO LATE THURSDAY...WITH
THURSDAY MORNING BEING THE TIMING CHOICE FOR THE TIME BEING. RAIN
CHANCES WILL EXIST ALONG THE FRONT...ESPECIALLY AS THE UPPER LEVEL
LOW PUSHES INTO THE REGION. PWATS OVER 1.3 INCHES WILL BE MORE THAN
ENOUGH TO AID IN MODERATE RAINFALL AMOUNTS. RAIN CHANCES WILL BE
HIGHEST THURSDAY NIGHT INTO EARLY FRIDAY AS A JET MAX PUSHES IN FROM
THE WEST ON THE SOUTHEAST SIDE OF THE LOW. AS OF NOW THE JET MAX IS
GREATEST OVER OUR SOUTHEASTERN ZONES. THIS COMBINED WITH A DIFFLUENT
UPPER PATTERN SHOULD BE MORE THAN EFFICIENT IN DEVELOPING PRECIP.
THE LOW WILL HAVE AN EXTENDED VISIT AND REMAIN OVERHEAD THROUGH LATE
SUNDAY BEFORE ZONAL FLOW TAKES OVER. TEMPERATURES WILL BE RELATIVELY
COOL IN THE SENSE OF TEMPS WILL BE AROUND SEASONAL AVERAGES BUT
COOLER THAN THEY WILL BE EARLIER THIS WEEK. DEPENDING ON THE
STRENGTH OF THE FRONT...SOME AREAS SUCH AS THE TEXAS PANHANDLE MAY
SEE BELOW AVERAGE TEMPS AS COOL AIR OVER MT INTO CA WILL BE PUSHED
SOUTHWARD. AS OF THIS AFTERNOON...PARTS OF INTERIOR MT HAVE FAILED
TO REACH INTO THE 50S. AS OF NOW THE COOLEST AIR WITH THE FRONT
LATER THIS WEEK SHOULD STAY TO OUR NORTH WITH THE COOL SIDE OF THE
FORECAST BEING IN THE UPPER 50S.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 65 92 63 90 62 / 10 20 20 10 10
TULIA 69 95 65 93 64 / 10 10 20 10 10
PLAINVIEW 65 95 64 92 64 / 10 10 10 10 10
LEVELLAND 67 94 65 91 64 / 10 10 20 10 10
LUBBOCK 72 96 68 94 68 / 10 10 10 10 10
DENVER CITY 67 95 65 92 65 / 10 10 10 10 10
BROWNFIELD 66 96 66 93 66 / 10 10 10 10 10
CHILDRESS 73 101 72 98 72 / 20 10 10 10 10
SPUR 70 100 68 96 68 / 20 0 10 0 10
ASPERMONT 75 102 72 99 71 / 60 0 10 0 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
33
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1154 PM CDT SUN AUG 24 2014
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 243 PM CDT SUN AUG 24 2014
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW UPPER LEVEL
LOW PRESSURE OVER EASTERN MONTANA AND A DOUBLE BARRELED SURFACE LOW
OVER NORTH DAKOTA. A WARM FRONT EXTENDS FROM THIS SURFACE LOW OVER
SOUTHWEST WISCONSIN...WHICH MARKS THE TRANSITION FROM MOSTLY CLOUDY
SKIES TO CLEAR CONDITIONS. A COLD FRONT EXTENDS SOUTHWARD OVER THE
CENTRAL PLAINS AND IS LARGELY INACTIVE AT THIS HOUR THOUGH THAT
MIGHT BE CHANGING OVER CENTRAL MINNESOTA WHERE ML CAPES HAVE
EXCEEDED 2000 J/KG. A FEW OTHER ELEVATED STORMS CONTINUE TO DEVELOP
OVER NORTHWEST WISCONSIN WITHIN THE TAIL END OF A VORT MAX. WILL
ADD A CHANCE TO N-C WISCONSIN BETWEEN 21Z AND 00Z. AS THE UPPER LOW
AND COLD FRONT MOVE EAST...THUNDERSTORM AND SEVERE WEATHER CHANCES
ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE LARGE UPPER LOW WILL MOVE ACROSS NORTH DAKOTA INTO THE
LAKE WINNIPEG REGION. MID-LEVEL HEIGHT FALLS FROM THE SYSTEM WILL
MOVE INTO THE WESTERN GREAT LAKES...WHICH WILL HELP PUSH A WEAK COLD
FRONT INTO WESTERN WISCONSIN AFTER MIDNIGHT. CONVERGENCE ALONG THE
FRONT IS RELATIVELY WEAK...BUT ELEVATED INSTABILITY APPROX 1000-1500
J/KG (ROUGH ESTIMATE) WILL MOVE INTO CENTRAL AND NORTH-CENTRAL
WISCONSIN AFTER MIDNIGHT. BECAUSE OF THE WEAK FORCING...KEPT
CHANCES OF PRECIP IN THE SCATTERED RANGE. THE MAGNITUDE OF CAPE AND
WIND SHEAR AROUND 30 KTS WOULD SUPPORT A CHANCE OF STRONG STORMS
THAT COULD PRODUCE NEAR SEVERE HAIL AND WIND GUSTS. WILL LEAVE A
MENTION OF THIS POSSIBILITY IN THE HWO. THE MESO MODELS CONTINUE TO
SHOW CONVECTION DEVELOPING OVER CENTRAL MINNESOTA LATER THIS
AFTERNOON BEFORE TRACKING THE STORMS INTO NORTH-CENTRAL WISCONSIN
AFTER 06Z. THIS STILL SEEMS POSSIBLE BASED ON THE DESTABILIZATION
TAKING PLACE OVER CENTRAL MINNESOTA. THE STORMS SHOULD WEAKEN AS
THEY MOVE EAST LATE TONIGHT DUE TO DIMINISHING INSTABILITY.
OTHERWISE...LOOK FOR A MUGGY EVENING WITH LOWS DROPPING INTO THE
MIDDLE AND UPPER 60S.
MONDAY...THE FRONT WILL MAKE LITTLE PROGRESS TO THE EAST AND INTO
NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. SPOTTY SHOWERS AND
STORMS WILL BE POSSIBLE AHEAD OF THE FRONT DURING THE MORNING ACROSS
MUCH OF THE AREA. ASSUMING COVERAGE IS NOT MORE THAN
ADVERTISED...LOW LEVEL SOUTHWEST WINDS WILL PUSH TEMPS INTO THE
UPPER 80S OR LOWER 90S OVER THE EASTERN FORECAST AREA. COMBINED
WITH DEWPOINTS AROUND 70 DEGREES...ML CAPES ARE PROJECTED TO REACH
2K-3K J/KG WITH BULK SHEARS AROUND 30 KTS. CONVERGENCE ALONG THE
FRONT WILL REMAIN WEAK BUT CANNOT RULE OUT ISOLATED OR SCATTERED
STRONG TO SEVERE STORMS OVER THE EAST DURING THE AFTERNOON WITH THAN
KIND OF INSTABILITY AND SHEAR. DRIER MID-LEVEL AIR WILL WORK INTO
CENTRAL AND NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON...WHICH
WILL MAKE IT HARDER FOR STORMS TO INITIATE. THE COMBINATION OF HEAT
AND HUMIDITY WILL PUSH HEAT INDICES INTO THE MIDDLE 90S.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 243 PM CDT SUN AUG 24 2014
MODELS CONTINUE TO INDICATE A RATHER AMPLIFIED MEAN FLOW PATTERN ACROSS
THE CONUS WITH AN UPPER TROF CURRENTLY OVER THE INTER MOUNTAIN
WEST AND SIG RIDGE OVER THE EASTERN LAKES. THE MOVEMENT OF UPPER
LOW OUT OF TROF INTO THE WESTERN LAKES EARLY IN THE PERIOD WILL BE
THE PRIMARY WEATHER FEATURE TO IMPACT OUR WEATHER. BY LATE THIS
WEEK...MODELS CONTINUE TO SHOW LINGERING PIECE OF TROF MEANDERING
INTO THE CENTRAL U.S. THE MOVEMENT OF THIS FEATURE CONTINUES TO
SLOW AS IT REMAINS CUT OFF FROM MAIN BAND OF WESTERLIES EXPECTED
TO LIE OVER SOUTHERN CANADA. FORECAST CONFIDENCE LOW THU NIGHT
ONWARD.
TREND IN SHORTER RANGE IS TO CONTINUE TO SLOW PASSAGE OF COLD
FRONT MONDAY WITH FRONT STILL BISECTING CWA AT 00Z TUE. HAVE
CONTINUE SCATTERED/CHANCE POPS MAINLY SOUTH AND EAST GIVEN
AVAILABLE INSTABILITY. LITTLE DYNAMICS BESIDES FRONT TO SUPPORT
GOING ANY HIGHER WITH POPS.
CONSISTENCY SEEN IN MODELS TO PUSH FRONT AND PCPN MAINLY SOUTH OF
CWA AS HIGH PRESSURE AND DRIER AIR MASS MOVES IN OVER NORTHERN WI
TUE INTO THU. CONCERN THIS PERIOD ON TEMPS. DRIER AIR...SUN AND
LOW LEVEL TEMPS AT OR SLIGHTLY BELOW NORMAL SHOULD SUPPORT TEMPS IN
THE LOWER TO MIDDLE 70S. WILL HAVE EAST FLOW OFF LAKE THOUGH LAKE
SURFACE TEMPS NOW IN MID TO UPPER 60S SO HAVE CONFINED COOLING TO
CLOSER TO THE COAST. HAVE BUMPED MAX TEMPS UP A BIT MID WEEK.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1153 PM CDT SUN AUG 24 2014
AN AREA OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS
THE AREA OVERNIGHT. THE ACTIVITY WILL PROBABLY ARRIVE IN
RHINELANDER AND WAUSAU BETWEEN 07 AND 09Z AND AT APPLETON...
OSHKOSH AND GREEN BAY BETWEEN 11Z AND 13Z IF IT HOLDS TOGETHER.
MVFR CEILINGS ARE A EXPECTED IN MOST PLACES WITH LOCAL IFR IN THE
NORTH.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......RDM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1023 PM MDT SUN AUG 24 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 345 PM MDT SUN AUG 24 2014
QUIET DAY TODAY WITH FAIR WEATHER CU DEVELOPING ACROSS THE AREA.
DEEP MIXING AND GUSTY WESTERLY WINDS HAVE RESULTED IN QUITE A BIT
OF DRIER AIR ALOFT MIXING DOWN TO THE SURFACE THIS
AFTERNOON...WITH NO DEEP CONVECTION OBSERVED. THE UPPER LEVEL LOW
WHICH BROUGHT RAIN AND TSTORMS TO THE AREA THE LAST FEW DAYS HAS
MOVED INTO NORTH DAKOTA AND WILL EVENTUALLY PUSH INTO
CANADA...WHILE THE NEXT WEATHER CONCERN FOR THIS WEEK IS CURRENTLY
DIGGING SOUTH ACROSS THE PACIFIC NORTHWEST. THIS IS THE NEXT UPPER
LEVEL TROUGH TO LIKELY IMPACT THE FORECAST AREA AND WILL EVENTUALLY
BECOME AN UPPER LEVEL LOW NEAR THE CENTRAL ROCKY MOUNTAINS BY THE
MIDDLE OF THE WEEK. BEFORE THEN...THIS SYSTEM WILL PRIMARILY ALLOW
THE JET STREAM TO SHIFT BACK TO THE NORTH AND INTENSIFY OVER THE
AREA TONIGHT. THERE IS A POTENTIAL FOR NOCTURNAL
CONVECTION...INCLUDING THUNDERSTORMS...TONIGHT ACROSS THE SOUTHERN
HALF OF THE FORECAST AREA...MAINLY SOUTH OF THE NORTH PLATTE RIVER
VALLEY.
THE UPPER LEVEL TROUGH WILL DIG SOUTH INTO THE GREAT BASIN ON
MONDAY. MODELS HAVE CONTINUED TO TREND SLOWER AND MORE AMPLIFIED
WITH THIS SYSTEM OVER THE LAST 3 DAYS AS THE TROUGH BECOMES A
CLOSED LOW SOMEWHERE BETWEEN NORTHERN NEVADA AND NORTHWEST
COLORADO. THE ECMWF AND GEM CONTINUE TO BE THE SLOWEST...WITH THE
GFS AND NAM NOT TOO FAR BEHIND NOW SINCE BOTH SOLUTIONS ARE
TRENDING TOWARDS THE ECMWF. WITH DECENT LOW TO MIDLEVEL
INSTABILITY...MOISTURE ADVECTION...AND CAPE OVER 1000
J/KG...EXPECT AFTERNOON SHOWERS AND TSTORMS TO DEVELOP ACROSS MOST
OF THE AREA. WITH THE LACK OF A DEFINED SHORTWAVE...DO NOT EXPECT
WIDESPREAD COVERAGE. IN FACT...MOST OF THE PANHANDLE MAY NOT SEE
ANY ACTIVITY AT ALL DUE TO THE CAP INVERSION AT 750 MB. KEPT
ISOLATED TSTORMS OVER THAT AREA AT BEST DURING THE AFTERNOON...BUT
MAY SEE AN INCREASE IN SHOWERS AND TSTORMS IN THE EVENING HOURS. A
FEW THUNDERSTORMS MAY BECOME STRONG OVER SOUTHEAST WYOMING. HIGH
TEMPERATURES WILL STRUGGLE TO REACH THE MID TO UPPER 70S ACROSS
MOST OF THE AREA DUE TO INCREASING SOUTHEAST WINDS.
SLOW MOVING CLOSED LOW WILL BARELY MAKE IT INTO WESTERN UTAH BY
TUESDAY...WITH ANOTHER DAY OF THUNDERSTORMS EXPECTED. TUESDAY
LOOKS TO BE A RATHER WET DAY AND ON THE COOL SIDE. ALTHOUGH THE
MAIN LOW WILL BE WELL TO THE WEST...MODELS INDICATE A POTENT
SHORTWAVE DISTURBANCE MOVING NORTHWARD OVER THE AREA. THE POSITION
AND TIMING OF THIS DISTURBANCE WILL INDICATE WHICH AREAS RECEIVE
LOCALLY HEAVY RAINFALL AND THE POTENTIAL FOR SEVERE TSTORMS.
INCREASED POP BETWEEN 40 TO 70 PERCENT ACROSS SOUTHEAST WYOMING ON
TUESDAY/TUESDAY EVENING. WESTERN NEBRASKA WILL STILL BE STRUGGLING
WITH A STRONG CAP INVERSION...SO KEPT POP BELOW 25 PERCENT FROM
SIDNEY TO CHADRON.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY NIGHT)
12Z MODELS HAVE COME INTO SOME AGREEMENT WITH THE UPPER LEVEL LOW
THAT IS EXPECTED TO TRACK ACROSS THE ROCKIES ON WEDNESDAY AND
THURSDAY. AS IT STANDS...MODELS CONTINUE TO FAVOR THE SLOWER
EAST-SOUTHEAST PROGRESSION OF THE UPPER LOW...TRACKING IT OVER THE
ROCKIES THROUGH THURSDAY AND INTO THE CENTRAL PLAINS FRIDAY. THUS
WILL CONTINUE TO RELY MORE ON THIS SLOWER SOLUTION FOR THE EXTENDED
FORECAST. TEMPS WILL REMAIN BELOW AVERAGE WEDNESDAY AND THURSDAY
WITH AT LEAST A CHANCE FOR SCATTERED SHOWERS AND T-STORMS AS THE
UPPER LOW MOVES ACROSS WY/CO ON WEDNESDAY. WILL SEE A STEADY
DECREASE IN COVERAGE FROM WEST TO EAST THURSDAY. PWATS ARE PROGGED
TO BE 0.75 TO 1" OR MORE...AND WITH FAIRLY LIGHT STEERING FLOW OF 10
TO 15 KTS IN PLACE...THIS ACTIVITY COULD BE SLOW MOVING AND PRODUCE
HIGH RAIN RATES. THEREFORE FLOODING WILL BE THE MAIN CONCERN WITH
THIS SYSTEM. MODELS SHOW H7 TEMPS DROPPING TO 3C OVER THE MOUNTAINS
ON WEDNESDAY AS THE LOW CENTER MOVES OVERHEAD...SO ITS VERY POSSIBLE
THE HIGH ELEVATIONS ABOVE 10KFT WILL SEE SNOW MIXED IN WITH RAIN.
THIS SYSTEM WILL SLOWLY DEPART THE REGION THROUGH THE WEEKEND WITH A
WEAK RIDGE BUILDING IN FROM THE WEST FOR FRIDAY AND SATURDAY. A MUCH
DRIER AIRMASS WILL MOVE IN WITH THE RIDGE SO CHANCES FOR AFTN
SHOWERS AND STORMS WILL BE LOW THROUGH SATURDAY NIGHT. BREEZY
CONDITIONS ARE LIKELY ON SATURDAY AS THE LEESIDE SFC PRESSURE TROUGH
DEEPENS IN ADVANCE OF THE NEXT SYSTEM DIGGING INTO THE PAC NW FRI
NIGHT INTO SATURDAY. TEMPS WILL WARM BACK TO MORE NORMAL READINGS
FOR THIS TIME OF YEAR BY SATURDAY AS WELL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1020 PM MDT SUN AUG 24 2014
CONVECTION ON THE INCREASE ACROSS NORTHWESTERN COLORADO LATE THIS
EVENING. SOME LIGHTNING STRIKES VCNTY OF SARATOGA WYOMING. EXPECT
THESE STORMS TO EVENTUALLY MAKE IT INTO KLAR AND KCYS TOWARDS THE
07-08Z TIME FRAME. HRRR SHOWS THIS AREA OF SHOWERS AND
THUNDERSTORMS EVENTUALLY MAKING IT INTO THE PANHANDLE TOWARDS 12Z
BEFORE DISSIPATING. MORE WIDESPREAD SHOWERS AND THUNDERSTORMS
EXPECTED FOR MONDAY AFTERNOON AND EVENING.
&&
.FIRE WEATHER...
ISSUED AT 245 PM MDT SUN AUG 24 2014
NO FIRE WEATHER CONCERNS THIS WEEK DUE TO THE UNSETTLED WEATHER
PATTERN OVER THE AREA. AFTER A RATHER DRY DAY ON SUNDAY...MOISTURE
WILL QUICKLY RETURN TO THE AREA TONIGHT. MINIMUM RELATIVE
HUMIDITIES WILL TREND HIGHER...BETWEEN 30 TO 50 PERCENT ALONG
WITH EXCELLENT RECOVERIES OVERNIGHT. TEMPERATURES WILL BE COOLER
THAN NORMAL ACROSS MOST LOCATIONS THROUGH AT LEAST THURSDAY.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...TJT
LONG TERM...RJM
AVIATION...CLAYCOMB
FIRE WEATHER...TJT
AREA FORECAST DISCUSSION
NWS MIAMI FL
1030 AM EDT MON AUG 25 2014
.UPDATE...A SURFACE TROUGH IS LOCATED ALONG THE PALM BEACH-MARTIN
COUNTY LINE AT THIS TIME...AND WILL MOVE SOUTHWEST ACROSS SOUTH
FLORIDA TODAY. MOISTURE AND CONVERGENCE ALONG THIS FEATURE...ALONG
WITH ADDITIONAL CONVERGENCE AIDED BY THE SEA BREEZES...WILL LEAD
TO A GOOD COVERAGE OF THUNDERSTORMS THIS AFTERNOON. A FEW COULD
CONTAIN GUSTY WINDS TO AROUND 50 MPH GIVEN THE PRESENCE OF DRY
MID LEVEL AIR AND INSTABILITY. THE INHERITED FORECAST LOOKS GOOD
WITH CURRENT AND EXPECTED TRENDS, SO NO SIGNIFICANT CHANGES ARE
NECESSARY THIS MORNING. WINDS WILL PICK UP BEHIND THIS TROUGH WITH
A SMALL CRAFT ADVISORY POSSIBLY NEEDED BY THIS EVENING FOR THE
PALM BEACH WATERS. FOLLOW US ON TWITTER @NWSMIAMI. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 749 AM EDT MON AUG 25 2014/
AVIATION...
SURFACE FLOW SHOULD REMAIN NORTHERLY THROUGH THE MORNING TO
NORTHEAST BY THE AFTERNOON. A SURGE OF ASSOCIATED MOISTURE WILL
KEEP ISOLATED TO SCATTERED SHOWERS PUSHING SOUTH ACROSS THE
ATLANTIC WATERS THROUGH THE MORNING. A FEW OF THESE SHOWERS MAY
MAKE IT INTO KFXE SOUTHWARD. THEREFORE KEPT VCSH AT THESE
TERMINALS THROUGH THE REMAINDER OF THE MORNING. OTHERWISE...VFR
CONDITIONS ARE EXPECTED OUTSIDE OF ANY AFTERNOON CONVECTION.
PREV DISCUSSION... /ISSUED 256 AM EDT MON AUG 25 2014/
SHORT TERM (TODAY-WEDNESDAY)...
IT CONTINUES TO LOOK MORE FAVORABLE THAT T.S. CRISTOBAL WILL MOVE
NORTH AND NORTHEAST AWAY FROM SOUTH FLORIDA. SO THE PRIMARY IMPACTS
WILL BE AN INCREASE IN RIP CURRENTS AT THE ATLANTIC BEACHES AND
BUILDING SEAS IN THE ATLANTIC FOR MARINE INTERESTS AS A SMALL
NORTHEAST SWELL IS GENERATED. MODELS SUGGEST A MOISTURE SURGE MOVING
INTO THE REGION AFTER 12Z THIS MORNING WHICH IS A RESULT IN THE
NORTHEAST CIRCULATION DEVELOPING WITH CRISTOBAL. THE CURRENT PWAT IS
AROUND 1.75 INCHES WITH FORECAST SOUNDINGS SHOWING AN INCREASE TO 2+
INCHES THIS MORNING. THE STEERING FLOW WILL BE NORTHEAST TO
SOUTHWEST SO THE EAST COAST COULD GET A QUICK PASSING SHRA/TSRA WITH
THE GREATEST ACTIVITY BEING OVER THE INTERIOR AND SOUTHWEST COAST.
THE HRRR IS SHOWING SOMETHING VERY SIMILAR WITH SCATTERED SHOWERS
NEAR THE EAST COAST WITH A FLARE UP INLAND AROUND THE LAKE AFTER
17Z. MUCH DRIER AIR ALOFT WILL THEN MOVE INTO SOUTH FLORIDA ON
TUESDAY WITH FORECAST SOUNDINGS SHOWING PWAT DROPPING TO LESS THAN
1.25 INCHES WITH THE NORTHEAST STEERING FLOW CONTINUING SO ONLY
ISOLATED OR LOW END SCATTERED IS EXPECTED ACROSS THE INTERIOR AND
SOUTHWEST COAST TUESDAY AFTERNOON/EVENING. THEY DRYING TREND WILL
PERSIST INTO WEDNESDAY ALTHOUGH FORECAST SOUNDINGS DO SHOW A
SLIGHT RETURN OF MOISTURE WITH PWAT CLIMBING BACK TO OVER 1.5
INCHES BY LATE IN THE DAY. STILL, NOT MUCH COVERAGE IS ANTICIPATED
WITH A MORE SOUTHEAST STEERING FLOW PATTERN RETURNING SO STORMS
WOULD TEND TO FORM INLAND FROM THE EAST COAST AND BE CONCENTRATED
OVER THE INTERIOR ONLY.
LONG TERM (THURSDAY-SUNDAY)...
AS CRISTOBAL EXITS TO THE NORTHEAST, A DEEP LAYER RIDGE WILL BUILD
BACK TO THE NORTH LATE THIS WEEK INTO THE UPCOMING WEEKEND WITH AN
INCREASE IN MOISTURE AND PWATS RETURNING TO NEAR NORMAL VALUES. THIS
WOULD CONTINUE TO STEER THE STORMS AWAY FROM THE EAST COAST TO THE
INTERIOR AND WEST COAST REGIONS. NO OTHER TROPICAL SYSTEMS ARE
EXPECTED TO AFFECT SOUTH FLORIDA THROUGH THE EXTENDED PERIOD.
MARINE...
NORTHEAST WINDS WILL PREVAIL THROUGH MIDWEEK, STRENGTHENING A TAD
TODAY AND TUESDAY AS THE PRESSURE GRADIENT TIGHTENS. THIS WILL
LEAD TO INCREASING SEAS ESPECIALLY IN THE GULF STREAM OFF THE PALM
BEACH COAST...WHERE HAZARDOUS SEAS OF 7+ FT ARE POSSIBLE DUE TO
FLOW COUNTERACTING THE GULF STREAM CURRENT ALONG WITH AN INCOMING
SMALL NORTHEAST SWELL.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 91 80 91 79 / 40 20 10 10
FORT LAUDERDALE 91 81 92 81 / 40 20 10 10
MIAMI 89 80 91 79 / 60 20 10 10
NAPLES 92 78 93 77 / 60 30 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
749 AM EDT MON AUG 25 2014
.AVIATION...
SURFACE FLOW SHOULD REMAIN NORTHERLY THROUGH THE MORNING TO
NORTHEAST BY THE AFTERNOON. A SURGE OF ASSOCIATED MOISTURE WILL
KEEP ISOLATED TO SCATTERED SHOWERS PUSHING SOUTH ACROSS THE
ATLANTIC WATERS THROUGH THE MORNING. A FEW OF THESE SHOWERS MAY
MAKE IT INTO KFXE SOUTHWARD. THEREFORE KEPT VCSH AT THESE
TERMINALS THROUGH THE REMAINDER OF THE MORNING. OTHERWISE...VFR
CONDITIONS ARE EXPECTED OUTSIDE OF ANY AFTERNOON CONVECTION.
&&
.PREV DISCUSSION... /ISSUED 256 AM EDT MON AUG 25 2014/
SHORT TERM (TODAY-WEDNESDAY)...
IT CONTINUES TO LOOK MORE FAVORABLE THAT T.S. CRISTOBAL WILL MOVE
NORTH AND NORTHEAST AWAY FROM SOUTH FLORIDA. SO THE PRIMARY IMPACTS
WILL BE AN INCREASE IN RIP CURRENTS AT THE ATLANTIC BEACHES AND
BUILDING SEAS IN THE ATLANTIC FOR MARINE INTERESTS AS A SMALL
NORTHEAST SWELL IS GENERATED. MODELS SUGGEST A MOISTURE SURGE MOVING
INTO THE REGION AFTER 12Z THIS MORNING WHICH IS A RESULT IN THE
NORTHEAST CIRCULATION DEVELOPING WITH CRISTOBAL. THE CURRENT PWAT IS
AROUND 1.75 INCHES WITH FORECAST SOUNDINGS SHOWING AN INCREASE TO 2+
INCHES THIS MORNING. THE STEERING FLOW WILL BE NORTHEAST TO
SOUTHWEST SO THE EAST COAST COULD GET A QUICK PASSING SHRA/TSRA WITH
THE GREATEST ACTIVITY BEING OVER THE INTERIOR AND SOUTHWEST COAST.
THE HRRR IS SHOWING SOMETHING VERY SIMILAR WITH SCATTERED SHOWERS
NEAR THE EAST COAST WITH A FLARE UP INLAND AROUND THE LAKE AFTER
17Z. MUCH DRIER AIR ALOFT WILL THEN MOVE INTO SOUTH FLORIDA ON
TUESDAY WITH FORECAST SOUNDINGS SHOWING PWAT DROPPING TO LESS THAN
1.25 INCHES WITH THE NORTHEAST STEERING FLOW CONTINUING SO ONLY
ISOLATED OR LOW END SCATTERED IS EXPECTED ACROSS THE INTERIOR AND
SOUTHWEST COAST TUESDAY AFTERNOON/EVENING. THEY DRYING TREND WILL
PERSIST INTO WEDNESDAY ALTHOUGH FORECAST SOUNDINGS DO SHOW A
SLIGHT RETURN OF MOISTURE WITH PWAT CLIMBING BACK TO OVER 1.5
INCHES BY LATE IN THE DAY. STILL, NOT MUCH COVERAGE IS ANTICIPATED
WITH A MORE SOUTHEAST STEERING FLOW PATTERN RETURNING SO STORMS
WOULD TEND TO FORM INLAND FROM THE EAST COAST AND BE CONCENTRATED
OVER THE INTERIOR ONLY.
LONG TERM (THURSDAY-SUNDAY)...
AS CRISTOBAL EXITS TO THE NORTHEAST, A DEEP LAYER RIDGE WILL BUILD
BACK TO THE NORTH LATE THIS WEEK INTO THE UPCOMING WEEKEND WITH AN
INCREASE IN MOISTURE AND PWATS RETURNING TO NEAR NORMAL VALUES. THIS
WOULD CONTINUE TO STEER THE STORMS AWAY FROM THE EAST COAST TO THE
INTERIOR AND WEST COAST REGIONS. NO OTHER TROPICAL SYSTEMS ARE
EXPECTED TO AFFECT SOUTH FLORIDA THROUGH THE EXTENDED PERIOD.
MARINE...
NORTHEAST WINDS WILL PREVAIL THROUGH MIDWEEK, STRENGTHENING A TAD
TODAY AND TUESDAY AS THE PRESSURE GRADIENT TIGHTENS. THIS WILL
LEAD TO INCREASING SEAS ESPECIALLY IN THE GULF STREAM OFF THE PALM
BEACH COAST...WHERE HAZARDOUS SEAS OF 7+ FT ARE POSSIBLE DUE TO
FLOW COUNTERACTING THE GULF STREAM CURRENT ALONG WITH AN INCOMING
SMALL NORTHEAST SWELL.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 91 80 91 79 / 40 20 10 10
FORT LAUDERDALE 91 81 92 81 / 40 20 10 10
MIAMI 89 80 91 79 / 60 20 10 10
NAPLES 92 78 93 77 / 60 30 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1135 AM EDT MON AUG 25 2014
.SYNOPSIS...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL
DIRECT DRY AIR INTO THE AREA THROUGH MIDWEEK. TEMPERATURES WILL BE
NEAR NORMAL EARLY THIS WEEK THEN A WARMING TREND WILL DEVELOP FOR
MID-WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LARGE UPPER LEVEL RIDGE EXTENDED FROM THE SOUTHERN PLAINS TO
NEW ENGLAND WITH AN UPPER TROUGH WELL OFF THE EAST COAST. SURFACE
HIGH PRESSURE STRETCHED FROM THE NORTHEASTERN STATES ACROSS THE
CAROLINAS AND GEORGIA. WEAK COLD/DRY ADVECTION THIS AFTERNOON WITH
PWAT BELOW ONE INCH. SURFACE PRESSURE GRADIENT MODERATELY TIGHT SO
EXPECT SOME GUSTY NORTHEAST WINDS THIS AFTERNOON. TEMPERATURES
WILL BE SEASONABLE WITH HIGHS IN THE RANGING THROUGH THE 80S UNDER
SUNNY SKIES.
MOIST ONSHORE LOW COULD BRING AN AREA OF CLOUDS ACROSS THE AREA
OVERNIGHT. BOTH THE RUC AND NAM INDICATE PWAT INCREASING TO NEAR
2.00 INCHES WITH AN INCREASE IN 8H50 MOISTURE. KEPT OVERNIGHT LOWS
IN LINE WITH GUIDANCE...RANGING THROUGH THE 60S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
HIGH PRESSURE DOMINATES THROUGH THE PERIOD. AIR MASS REMAINS DRY.
UPPER RIDGE BUILDING EAST THROUGH THE PERIOD SO WARMING TREND
DEVELOPING.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE WILL REMAIN OVER THE AREA FOR MUCH OF THE WEEK.
LATEST MODELS SUGGEST FRONT REMAINING NORTH OF THE REGION FRIDAY
AND RIDGE OVER THE AREA SO BACKED OFF ON POPS. ANOTHER COLD FRONT
MOVING IN FROM THE WEST SUNDAY. FORECASTED LOW CHANCE POPS FRIDAY
THROUGH SUNDAY. TEMPERATURES NEAR OR JUST SLIGHTLY BELOW NORMAL
MONDAY THROUGH WEDNESDAY...AND A LITTLE ABOVE NORMAL FOR THE
REMAINDER OF THE EXTENDED PERIOD.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
DRY HIGH PRESSURE BUILDING DOWN THE EASTERN SEABOARD...COUPLED WITH
AN UPPER RIDGE OVERHEAD...WILL ENSURE FAIR AND DRY WEATHER.
WINDS WILL BE NORTHEAST AROUND 10 KNOTS WITH GUST NEAR 20 KNOTS
THIS AFTERNOON.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
647 AM CDT MON AUG 25 2014
.UPDATE...
ISSUED AT 645 AM CDT MON AUG 25 2014
HAVE UPDATED THE FORECAST TO ADD EARLY MORNING FOG AND LOW CLOUDS
OVER THE FAR EAST...WHERE SURFACE REPORTS AND SATELLITE FOG
CHANNEL SHOWED THE EDGE OF A LARGER DECK OVER NE IL EDGING INTO
THE NW IL COUNTIES AND OCCASIONALLY LOWERING VISIBILITIES TO LESS
THAN 1 MILE. ELSEWHERE...THUNDERSTORMS CONTINUE TO TRAIN IN A SW
TO NE FASHION...PARALLEL TO THE UPPER LEVEL FLOW FROM CENTRAL IA
INTO SW WI. SO FAR...THE STORMS HAVE REMAINED MAINLY NW OF A LINE
FROM BELLE PLAINE THROUGH CENTRAL CITY TO DUBUQUE. RADAR ESTIMATES
INDICATE RAINFALL AMOUNTS OF A QUARTER INCH TO NEARLY 1.5 INCHES
HAS FALLEN OVER THE PAST SEVERAL HOURS IN THIS AREA.
CELLS SHOULD CONTINUE TO TRAIN ALONG THIS AXIS...AND POSSIBLY
SHIFT A BIT TO THE SOUTHEAST BEFORE DISSIPATING WITH THE LOSS OF
UPPER LEVEL SUPPORT AND THE DIURNAL WANING OF THE LOW LEVEL JET
THIS MORNING. EVEN WITH A POSSIBLE ADDITIONAL 1 INCH OF
RAIN...NOT ANTICIPATING ANY SIGNIFICANT HYDRO ISSUES AS FLASH
FLOOD GUIDANCE VALUES ARE MAINLY OVER 3 INCHES PER 3 HOURS IN THIS
AREA DUE TO THE RECENT DRY WEATHER.
&&
.SYNOPSIS...
ISSUED AT 334 AM CDT MON AUG 25 2014
THUNDERSTORMS HAVE DEVELOPED EARLY THIS MORNING ALONG AND AHEAD OF
THE SURFACE FRONT EXTENDING ROUGHLY FROM WESTERN LAKE SUPERIOR SW
ACROSS WESTERN WI...SW MN...INTO W CENTRAL IA. THIS WAS ALONG AN
AXIS OF HIGH THETAE INDICATED BY 850 MB DEWPOINTS OF 14 TO 16 C FROM
NORTHEAST KS INTO SW ONTARIO AT 00Z...WITH CONVERGENCE ASSISTED
BY 35KT TO 40 KT SW WINDS AT 850 MB. THIS MOISTURE WAS BEING
PULLED NORTHWARD BY A STRONG SURFACE AND UPPER LEVEL LOW SEEN ON
WV IMAGERY ALONG THE ND/MANITOBA BORDER. AT 3 AM...THE LEADING
LINE OF SCATTERED THUNDERSTORMS WAS MOVING INTO BUCHANAN AND
BENTON COUNTIES...INTO A VERY HUMID AIRMASS WITH DEWPOINTS IN THE
LOWER TO MID 70S AND AIR TEMPERATURES IN THE MID TO UPPER 70S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT MON AUG 25 2014
FORECAST CHALLENGES CENTER ON THUNDERSTORMS THIS MORNING AND AGAIN
TONIGHT...AND HEAT HEADLINES TODAY AS THE HOT AND HUMID CONDITIONS
PERSIST OVER THE REGION. IN THE NEAR TERM...A SEMI-LINEAR MCS WILL
LIKELY MOVE ACROSS THE FORECAST AREA MAINLY NORTH OF I-80...DRIVEN
BY A WEAK SHORTWAVE FLOW IN THE NW FLOW ALOFT. WHILE NO INDIVIDUAL
FORECAST MODEL HAS HAD A GOOD HANDLE ON TRENDS OVERNIGHT...THE
HIGH RES WRF AND RAP MODELS APPEAR TO HAVE THE BEST HANDLE ON THE
CONVECTION ENTERING THE NORTH. THESE HAVE THE THUNDERSTORMS ADVANCING
THROUGH THE NORTH OVER THE NEXT SEVERAL HOURS AND THEN DISSIPATING
BY NOON...AND HAVE TRENDED THE FORECAST ACCORDINGLY. THE LATEST
RAP IS ALONE WITH DEVELOPING THUNDERSTORMS IN THE HIGH MUCAPE
AXIS FURTHER SE...OVER 4000 J/KG...OVER W CENTRAL IL TOWARD
SUNRISE...WHICH WHILE NOT IN THE CURRENT FORECAST CANNOT BE
ENTIRELY RULED AND WILL WATCH TRENDS CLOSELY.
OTHERWISE...THIS SHOULD BE FOLLOWED BY CLEARING SKIES AND A RETURN
TO THE HEAT AND HUMIDITY SEEN OVER THE AREA YESTERDAY. DUE TO
UNCERTAINTIES IN THE TIMING OF THE DISSIPATING MCS IN THE NORTH AND
POSSIBLE DEBRIS CLOUDS FROM STORMS IN THE PLAINS...ALONG WITH 850 MB
TEMPERATURES PROGGED ABOUT 1 DEGREE COOLER...HAVE TRENDED HIGHS A
DEGREE OR TWO COOLER THAN SUNDAY...WITH UPPER 80S NW TO LOWER 90S
CENTRAL AND SOUTH. DEWPOINTS WILL HOLD IN THE LOWER TO MID 70S AND
POSSIBLY TOUCH THE UPPER 70S AT TIMES LATE IN THE DAY. THIS
COMBINATION WILL SEND HEAT INDEX VALUES TO JUST ABOVE 100 ACROSS
THE SOUTH AND WILL KEEP THE PREVIOUS HEAT ADVISORY CONFIGURATION
IN PLACE.
TONIGHT...THE SETUP WILL BE FAVORABLE FOR ANOTHER MCS AS THE SURFACE
FRONT SLOWLY ADVANCES THROUGH THE FORECAST AREA AND MODEST
CONVERGENCE OCCURS IN THE 850 MB THETAE AXIS AS IT SHIFTS OVERHEAD.
HAVE KEPT LIKELY POPS IN THE NORTH WITH SLIGHT TO LOW END CHANCE
POPS IN THE SOUTH TOWARD MORNING. THE MAIN THREAT WILL BE LOCALLY
HEAVY RAINFALL. IT WILL BE ANOTHER WARM AND VERY HUMID NIGHT WITH
TEMPERATURES AND DEWPOINTS IN THE 70S...EXCEPT IN THE FAR NW...WHERE
THE CURRENT FRONTAL TIMING SUGGESTS READINGS LOWERING INTO THE
UPPER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 334 AM CDT MON AUG 25 2014
AN ORGANIZED THUNDERSTORM COMPLEX SHOULD MOVE INTO THE AREA TUESDAY
MORNING AND DISSIPATE DURING THE MORNING. BOUNDARIES LEFT OVER FROM
THIS COMPLEX COMBINED WITH A WEAK FRONT MOVING THROUGH THE AREA WILL
PROVIDE THE FOCUS FOR NEW CONVECTION TUESDAY AFTERNOON AND EVENING.
HIGH MOISTURE LEVELS IN THE LOWER ATMOSPHERE MEANS ANY STORM WILL BE
CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL.
CLOUD COVER AND RAIN WILL PLAY INTO HOW WARM IT WILL GET ON TUESDAY.
THE SOUTHEAST HALF MAY SEE TEMPERATURES AROUND 90 WITH HEAT INDEX
READINGS IN THE UPPER 90S TO JUST OVER 100.
ANOTHER THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP IN WESTERN IOWA
TUESDAY EVENING AND THEN MOVE MAINLY EAST OVERNIGHT INTO WEDNESDAY
MORNING. THIS STORM COMPLEX SHOULD ARRIVE IN THE WESTERN THIRD OF
THE CWFA IN THE PRE-DAWN HOURS AND SLOWLY DISSIPATE ACROSS THE AREA
WEDNESDAY MORNING. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE FROM THE
STORMS DUE TO HIGH MOISTURE LEVELS.
LIKE TUESDAY...BOUNDARIES LEFT OVER FROM THE WEDNESDAY STORM COMPLEX
WILL PROVIDE THE FOCUS FOR NEW CONVECTION WEDNESDAY AFTERNOON AND
EVENING.
SIGNALS FROM THE MODELS SUGGEST YET ANOTHER THUNDERSTORM COMPLEX
WILL DEVELOP IN WESTERN IOWA WEDNESDAY EVENING AND MOVE GENERALLY
EAST OVERNIGHT AND ARRIVE IN THE WESTERN THIRD OF THE AREA IN THE
PRE-DAWN HOURS. LOCALLY HEAVY RAINFALL MAY BE POSSIBLE FROM SOME OF
THE STRONGER STORMS.
THURSDAY ON...
THE MODEL CONSENSUS HAS CHANCE POPS IN EACH 12 HOUR PERIOD FROM
THURSDAY THROUGH SATURDAY NIGHT. TEMPERATURES SHOULD BE NEAR NORMAL.
ON SUNDAY...THE MODEL CONSENSUS HAS SLIGHT CHANCE TO LOW CHANCE POPS.
THE LARGE SCALE PICTURE SUGGESTS THE WEATHER PATTERN WILL REMAIN
FAIRLY ACTIVE WITH A FRONT STALLED OUT JUST SOUTH OF THE AREA. IT
WILL NOT RAIN CONTINUOUSLY THE ENTIRE TIME. THERE WILL BE PERIODS OF
DRY WEATHER THAT MAY LAST 6 OR 12 HOURS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 645 AM CDT MON AUG 25 2014
A SLOW MOVING AXIS OF THUNDERSTORMS OVER NORTHEAST IOWA MAY
BRIEFLY IMPACT THE CID AND DBQ TERMINALS EARLY THIS MORNING. FOG
AND A FEW AREAS OF LOW CLOUDS WILL IMPACT MOST OF THE TERMINALS
WITH PERIODS OF MVFR CONDITIONS UNTIL MID MORNING.
OTHERWISE...TODAY WILL BE MAINLY VFR WITH VERY HUMID CONDITIONS.
ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED TO MOVE THROUGH EASTERN
IOWA AND NORTHWEST ILLINOIS LATE TONIGHT AS A COOL FRONT SLOWLY
DROPS SOUTH THROUGH THE AREA. THIS IS MOST LIKELY TO AFFECT THE
CID...DBQ AND MLI TERMINALS...WHERE PROB30 GROUPS COVER THE
POTENTIAL FOR NOW. ALSO...LIGHT WINDS AND LINGERING LOW LEVEL
MOISTURE WILL ALSO LEAD TO MVFR FOG...WHICH IS ALSO INCLUDED FOR
THE LATE NIGHT AND EARLY MORNING PERIODS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
LOUISA-MUSCATINE-SCOTT.
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR DES MOINES-HENRY
IA-LEE-VAN BUREN.
IL...HEAT ADVISORY FROM NOON TODAY TO 8 PM CDT THIS EVENING FOR
BUREAU-HENRY IL-MERCER-PUTNAM-ROCK ISLAND-WHITESIDE.
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR HANCOCK-HENDERSON-
MCDONOUGH-WARREN.
MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
UPDATE...SHEETS
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...08
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
745 AM EDT MON AUG 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EDT MON AUG 25 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS LOOKING
SHORTWAVE LIFTING THRU ND INTO MANITOBA. ASSOCIATED SFC LOW WAS
MOVING INTO SE MANITOBA WITH COLD FRONT EXTENDING THRU FAR ERN MN.
AS EXPECTED...SCT TSTMS DEVELOPED AHEAD OF FRONT IN MN LATE
YESTERDAY AFTN/EVENING. STORMS THEN ORGANIZED INTO A LINE AND PUSHED
E INTO WI/UPPER MI. AS OF 09Z...SHRA/TSTMS EXTENDED FROM NCNTRL LAKE
SUPERIOR TO THE HURON MTNS AND CRYSTAL FALLS. CONVECTION HAS HELD
TOGETHER FOR MUCH OF THE NIGHT...AND IT HAS ONLY BEEN IN THE LAST HR
OR TWO THAT A NOTABLE DIMINISHING TREND HAS BEGUN. NSSL WRF RUN FROM
00Z/24 AUG DID A GREAT JOB AND BETTER THAN ANY OTHER MODEL IN
CAPTURING WHAT OCCURRED LAST NIGHT INTO EARLY THIS MORNING...
INCLUDING THE DIMINISHING TREND NOW UNDERWAY.
WHILE THERE IS STILL SOME INCREASE IN INSTABILITY AHEAD OF
CONVECTION PER SPC MESOANALYSIS OF 3HR ML/MUCAPE CHANGE...OVERALL
MAGNITUDE OF INSTABILITY IS NOTABLY LESS THAN WHAT WAS SUPPORTING
THE CONVECTION EARLIER IN THE NIGHT. DIMINISHING INSTABILITY
COMBINED WITH WEAKENING LOW-LEVEL JET WILL CONTINUE TO CAUSE
SHRA/TSRA TO WEAKEN AS THEY PUSH E THIS MORNING. QUESTION THEN
BECOMES WHETHER THERE WILL BE REDEVELOPMENT ALONG THE MOISTURE AXIS
THAT WILL BE SLOWING DOWN. NSSL WRF INCLUDING THE NCEP ARW/NMM WHICH
ALSO DID WELL WITH CONVECTION LAST NIGHT SUGGEST LITTLE OR NO
ADDITIONAL DEVELOPMENT THIS AFTN. WILL BASICALLY FOLLOW THAT
SCENARIO GIVEN A LACK OF MUCH FORCING THIS AFTN. WITH INCREASING
SUNSHINE AND 850MB THERMAL RIDGE OVER THE AREA...TODAY SHOULD BE THE
WARMEST DAY OF THE WEEK. FCST SOUNDINGS SUPPORT MAX TEMPS AS HIGH AS
THE MID/UPPER 80S OVER ROUGHLY THE W HALF. COULD BE WARMER DEPENDING
ON HOW QUICKLY CLOUDS SCATTER OUT. E WILL BE COOLER WITH MORE CLOUD
COVER AND CONTINUED SOUTHERLY FLOW OFF LAKE MICHIGAN.
LOOKS LIKE A SECONDARY COLD FRONT/TROF WILL SWEEP ACROSS THE AREA
LATER THIS AFTN/EVENING. AS THE TROF MOVES INTO THE ERN FCST AREA
THIS EVENING WHERE MOISTURE/INSTABILITY LINGER...ISOLD SHRA AND
PERHAPS A TSRA MAY DEVELOP FROM ERN LAKE SUPERIOR INTO ERN UPPER MI.
OTHERWISE...EXPECT A DRY NIGHT...BECOMING COOLER AND LESS HUMID.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 403 AM EDT MON AUG 25 2014
A FAIRLY QUIET AND GENERALLY DRY LONG TERM PERIOD IS IN STORE FOR
THE UPPER GREAT LAKES REGION FOR TUESDAY THROUGH THE WEEKEND. THIS
TRANSITION WILL OCCUR AS A RESULT OF THE LOW PRESSURE SYSTEM MOVING
THROUGH NORTHERN ONTARIO TODAY AND THE ASSOCIATED COLD FRONT THAT
PASSES THROUGH. BEHIND THIS LOW AND ASSOCIATED SHORTWAVE...HIGH
PRESSURE FROM THE EASTERN DAKOTAS WILL SHIFT EAST OVER THE UPPER
GREAT LAKES REGION BY WEDNESDAY WHILE A WEAK UPPER TROUGH SWEEPS
THROUGH. IN GENERAL...EXPECT THIS HIGH PRESSURE RIDGE TO SUPPRESS
ANY PRECIPITATION TO THE SOUTH OF THE AREA THROUGH THURSDAY. THERE
ARE A COUPLE MINOR ITEMS TO NOTE. FIRST...THE SECONDARY SHORTWAVE
MOVING THROUGH THE FLOW LATE TUESDAY NIGHT INTO WEDNESDAY MORNING
COULD TRY TO SPARK AN ISOLATED SHOWER BUT FEEL THE DRY AIR IN THE
LOWER LEVELS ASSOCIATED WITH THE HIGH PRESSURE RIDGE WILL INHIBIT
ANY RAIN FROM REACHING THE SURFACE. THUS...WILL JUST SHOW PASSING
MID CLOUDS AS THAT WAVE MOVES THROUGH. THE OTHER ITEM IS THE MUCH
COOLER AIR BELOW 850MB THAT WILL BE SURGING INTO THE CWA LATE
TONIGHT INTO TUESDAY. THIS WILL SETUP A RETURN TO ANOTHER COOLER
PERIOD OF HIGH TEMPERATURES OVER THE CWA. WITH THE COLD AIR JUST
STARTING TO MOVE IN ON TUESDAY...HIGHS OVER THE CENTRAL/EAST WILL
STILL RISE INTO THE UPPER 60S AND LOWER 70S WHILE AREAS OVER THE
WEST NEAR LAKE SUPERIOR WILL STAY IN THE MID 60S WITH THE
GUSTY WESTERLY WIND OFF THE LAKE. WEDNESDAY WILL BE THE COOLEST DAY
(AIDED BY THE MORNING MID CLOUDS LIMITING HEATING AND MODEL AVERAGE
850MB TEMPS AROUND 6-7C)...WITH HIGHS IN THE 60S OVER MOST OF THE
CWA. 850MB TEMPS WILL REBOUND SLIGHTLY ON THURSDAY AND ALLOW HIGHS
TO BE IN THE UPPER 60S TO AROUND 70 DEGREES. ALONG WITH THAT COOLER
AIR ON TUESDAY MORNING...SOME OF THE MODELS ARE INDICATING ENOUGH
MOISTURE FOR SOME CLOUDS OVER THE NORTH HALF OF THE CWA. THINK THE
COVERAGE WILL BE THE GREATEST DURING THE AFTERNOON HOURS WHEN THE
DIURNAL HEATING IS MAXIMIZED AND WILL SHOW PARTLY CLOUDY SKIES
DURING THAT TIME. EXPECT MOSTLY CLEAR SKIES FOR THE REST OF THE
MIDDLE OF THE WORK WEEK.
THE FOCUS THURSDAY NIGHT INTO THE WEEKEND WILL BE THE UPPER
DISTURBANCE MOVING OUT OF THE CENTRAL ROCKIES AND INTO THE CENTRAL
PLAINS ON WEDNESDAY. THE INITIAL PORTION OF THIS WAVE WILL SHIFT
NORTHEAST TOWARDS THE UPPER GREAT LAKES REGION THURSDAY NIGHT AND
FRIDAY...WITH MODELS STILL VARYING ON THE NORTHWARD EXTENT OF THE
WAVE AND ASSOCIATED PRECIP. CURRENT CONSENSUS IS FOR IT TO BRUSH
THE SOUTHEAST THIRD OF THE CWA AND WILL SHOW SLIGHT CHANCES IN THAT
AREA. THE SECOND WAVE WILL PUSH THROUGH THE AREA FRIDAY NIGHT INTO
SATURDAY AND BRING ANOTHER OPPORTUNITY FOR PRECIPITATION. MODELS
ALSO VARYING ON THE LOCATION THIS WAVE...SO WILL FOLLOW A BLEND OF
GEM/GFS/ECMWF FOR POPS (SLIGHT OR LOW END CHANCES) WITH THE BEST
CHANCES OVER THE SOUTHEAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 745 AM EDT MON AUG 25 2014
AREA OF SHRA HAS MOVED E OF KIWD/KCMX. BEHIND THE SHRA...KIWD SHOULD
CONTINUE TO SEE VFR CONDITIONS. AT KCMX...IFR CIGS HAVE RECENTLY
ARRIVED. EXPECT THIS TO BE SHORT LIVED WITH A RETURN TO VFR BY MID
OR LATE MORNING. VFR CONDITIONS WILL THEN CONTINUE AT KIWD/KCMX FOR
THE REMAINDER OF THE FCST PERIOD AS DRIER AIR FLOWS INTO THE AREA
BEHIND A COLD FRONT. AT KSAW...-SHRA WILL END IN THE NEXT FEW HRS.
BASED ON OBS AROUND THE AREA...VFR CONDITONS WILL LIKELY PREVAIL...
BUT THERE MAY BE OCNL MVFR CIGS. VFR CONDITIONS WILL THEN BE THE
RULE FOR REMAINDER OF THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EDT MON AUG 25 2014
FOG MAY BE AN ISSUE OVER PORTIONS OF LAKE SUPERIOR THRU THIS
EVENING...MAINLY CNTRL/E AND ESPECIALLY NE GIVEN THE HUMID AIR MASS
AND PCPN THAT HAS OCCURRED. PASSAGE OF COLD FRONT AND ARRIVAL OF
DRIER AIR TODAY/THIS EVENING WILL THEN WORK TO CLEAR OUT THE FOG
FROM W TO E. BEHIND FRONT...WESTERLY WINDS WILL INCREASE TO
15-25KT OVER WRN LAKE SUPERIOR THIS AFTN AND THEN OVER CNTRL LAKE
SUPERIOR THIS EVENING. THESE STRONGER WINDS WILL LINGER INTO TUE
MORNING...THEN WINDS WILL DIMINISH AS HIGH PRES MOVES CLOSER TO THE
AREA. THE HIGH WILL SETTLE INTO THE UPPER LAKES TUE NIGHT THRU
THU...BRINGING A PERIOD OF LIGHTER WINDS MOSTLY UNDER 15KT. THE
LIGHTER WINDS WILL LINGER INTO FRI DESPITE THE HIGH MOVING TO THE E.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
1002 AM EDT MON AUG 25 2014
.DISCUSSION...
A BROAD UPPER-LEVEL HIGH PRESSURE RIDGE WILL CONTINUE TO BUILD INTO
THE TENNESSEE VALLEY TODAY...AND BECOME THE DOMINANT WEATHER
FEATURE ACROSS THE AREA FOR THE NEXT SEVERAL DAYS. HOWEVER FOR
TODAY...MOISTURE STILL PRESENT UNDERNEATH THIS RIDGE HAS RESULTED IN
SCATTERED TO LOCALLY DENSE CLOUD COVER THIS MORNING /ALONG WITH A
COUPLE OF ROGUE SHOWERS OVER THE PLATEAU/. AS DRY AIR BEGINS TO
WORK ITS WAY INTO THE REGION...THIS CLOUD COVER WILL GRADUALLY
BREAK UP AND SHIFT OFF TO THE WEST...RESULTING IN A MOSTLY TO
PARTLY SUNNY DAY ACROSS THE REGION. GIVEN THE STRONGER CAP
DEVELOPING ALOFT...AM NOT EXPECTING MUCH IN THE WAY OF CONVECTION
THIS AFTERNOON. BUT...THE HRRR IN PARTICULAR DOES HINT AT SOME
ISOLATED SHOWERS/STORMS DEVELOPING AFTER 18Z ALONG THE PLATEAU...
SO HAVE ADDED A SOME LOW-END MENTIONABLE POPS IN THIS AREA THIS
AFTERNOON. HIGHS WILL BE SLIGHTLY COOLER TODAY WITH THE CLOUD
COVER...BUT WILL STILL REACH THE MID TO UPPER 80S TODAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 88 67 91 66 / 20 0 0 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 87 65 88 64 / 10 0 0 10
OAK RIDGE, TN 87 66 89 64 / 10 0 0 10
TRI CITIES AIRPORT, TN 86 56 86 61 / 10 0 10 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
AMP
AREA FORECAST DISCUSSION
NWS PUEBLO CO
426 PM MDT MON AUG 25 2014
.UPDATE...
ISSUED AT 424 PM MDT MON AUG 25 2014
UPDATED FOR INCLUSION OF SVR TSTORM WATCH FOR EL PASO
CROWLEY AND KIOWA COUNTIES. ROSE
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM MDT MON AUG 25 2014
CURRENTLY...COLD FRONT HAS BECOME STATIONARY NEAR THE NM BORDER
THIS AFTERNOON...AND WILL LIKELY DRIFT BACK NORTHWARD TOWARD THE
ARKANSAS RIVER BY 00Z. CONVECTION OVER THE MOUNTAINS AND ALONG THE
RATON MESA HAS BEEN RELATIVELY WEAK SO FAR AS STORMS HAVE YET TO
TAP DEEPER INSTABILITY NEAR THE KS BORDER AND FARTHER NORTH NEAR THE
PALMER DIVIDE. WITH COOL AIR SLIGHTLY DEEPER THAN EXPECTED...APPEARS
HIGH TEMPS WILL END UP JUST SHY OF FORECAST READINGS.
TONIGHT...MESOSCALE MODELS CONTINUE TO POINT TO AREAS ALONG AND
NORTH OF THE PALMER DIVIDE HAVING THE BEST CHANCE FOR STRONG/SEVERE
CONVECTION...THOUGH LATEST HRRR HINTS AT SOME SOME BRIEF STRONGER
STORMS OVER THE FAR EASTERN PLAINS...AS FRONTAL BOUNDARY RETREATING
NORTHWARD PROVIDES SOME ENHANCED CONVERGENCE. WEAK SHORT WAVE...OVER
WRN CO CURRENTLY...WILL ALSO PROVIDE SOME UPWARD MOTION AS IT
CROSSES THE AREA THIS EVENING. BY MIDNIGHT...SUSPECT CONVECTION WILL
SHIFT NORTHEAST AND COALESCE INTO AN MCS OVER NWRN KS/SRN NEB...WITH
FAIRLY LARGE COLD POOL GIVING SURFACE FRONT A RENEWED SHOVE
SOUTHWARD THROUGH THE EASTERN PLAINS. WITH A GRADUAL INCREASE IN MID
LEVEL MOISTURE THROUGH THE NIGHT AND BOUNDARY MOVING BACK
SOUTHWARD...WILL ONLY GRADUALLY TAPER OFF POPS THROUGH THE
EVENING...WITH AT LEAST SOME ISOLATED TSRA POSSIBLE PAST MIDNIGHT.
TUESDAY.. UPPER LOW WILL CONTINUE TO SLOWLY PUSH EASTWARD THROUGH
THE GREAT BASIN...WITH STRENGTHENING S-SW FLOW AHEAD OF THE SYSTEM
PUSHING AN INCREASING AMOUNT OF TROPICAL MOISTURE NORTHWARD INTO
COLORADO. SURFACE FRONT WILL LIKELY STAY SOUTH OF THE ARKANSAS RIVER
THROUGH THE DAY...WITH E-SE FLOW PUSHING 55F-60F DEWPOINTS WESTWARD
TOWARD THE I-25 CORRIDOR. WITH MOISTURE PLENTIFUL...EXPECT EARLY
INITIATION OF CONVECTION WITH STORMS FIRING OVER THE MOUNTAINS
BEFORE 18Z AND SPREADING QUICKLY TO LOWER ELEVATIONS BY 21Z. MAIN
THREAT TOMORROW OVER ALL AREAS WILL BE HEAVY RAINFALL...THOUGH WITH
CAPES OVER 1000 J/KG AND 0-6KM SHEAR OF 30-40 KTS...A SEVERE STORM
OR TWO IS POSSIBLE ON THE PLAINS MAINLY ALONG AND NORTH OF THE
ARKANSAS RIVER. ALL IN ALL...IT LOOKS LIKE A VERY WET DAY OVER MUCH
OF SOUTHERN COLORADO...AND WITH CLOUDS AND PRECIP FAIRLY QUICK TO
DEVELOP...MAX TEMPS SHOULD COOL AT LEAST A FEW DEGF VERSUS MON
READINGS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM MDT MON AUG 25 2014
TUESDAY NIGHT THROUGH FRIDAY...LATEST RUNS OF THE NAM...GFS AND EC
MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE PROGRESSION OF THE UPPER
TROUGH ACROSS THE REGION THROUGH THIS WEEK. TUE EVENING THE TROUGH
WILL BE POISED OVER NV AND UT...CONTINUING TO DRAW A STRONG MOISTURE
PLUME UP ACROSS THE 4 CORNERS AND INTO CO. THE TROUGH STEADILY
MARCHES TO THE EAST ACROSS COLORADO THROUGH WED AND THU...WITH THE
TROUGH AXIS FINALLY REACHING THE OK AND TX PANHANDLES BY FRI
MORNING. A GOOD AMOUNT OF MOISTURE...COUPLED WITH AVAILABLE DYNAMICS
AND A COLD FRONT WED EVE WILL PROVIDE FOR WIDESPREAD CONVECTION
CHANCES THROUGH THE PERIOD...WITH PCPN FINALLY TAPERING OFF FRI
MORNING. LOOK FOR SCATTERED POPS FOR MUCH OF THE AREA TUE EVE AND
AGAIN WED EVE THROUGH THU...WITH PCPN LIKELY OVER THE MTS. TEMPS ARE
EXPECTED TO REMAIN COOLER THROUGH FRI WITH MAX TEMPS IN THE UPPER
70S AND 80S FOR THE PLAINS...AND 60S AND 70S FOR THE HIGH VALLEYS.
SATURDAY THROUGH MONDAY...AS THE TROUGH EXITS TO THE EAST...A RIDGE
OF HIGH PRESSURE BUILDS OVER THE SW US. THIS WILL HELP A DRYING AND
WARMING TREND TO TAKE HOLD OVER THE WEEKEND AND INTO THE FIRST PART
OF THE NEXT WORK WEEK. PCPN CHANCES ARE FORECAST TO BE RESTRICTED TO
JUST ISOLATED DIURNAL ACTIVITY OVER THE HIGHER TERRAIN...AND TEMPS
WILL CLIMB BACK UP INTO THE 80S NEARING 90 F FOR THE PLAINS...AND
INTO THE 80S FOR THE HIGH VALLEYS. MOORE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 305 PM MDT MON AUG 25 2014
TSRA DEVELOPING OVER THE MOUNTAINS WILL CONTINUE TO SPREAD TO LOWER
ELEVATIONS THIS AFTERNOON...WITH STORMS NEAR KCOS AND KPUB IN THE
22Z-02Z PERIOD...AND AROUND KALS 22Z-01Z. WITH MORE MOISTURE
AVAILABLE TODAY...EXPECT LOWER CLOUD BASES AND RESTRICTED VISIBILITY
UNDER THE STRONGEST STORMS...AND LOCAL MVFR/BRIEF IFR CONDITIONS
WILL BE POSSIBLE. STORMS WILL GRADUALLY SHIFT INTO NORTHEAST
COLORADO THIS EVENING AND OVERNIGHT...WITH A COLD FRONT AND SHIFT TO
NORTHEAST WINDS PUSHING SOUTHWARD ACROSS THE PLAINS AFTER 00Z. MAY
SEE SOME IFR STRATUS ALONG THE PALMER DIVIDE BY 12Z TUE...BUT
HAVEN`T INCLUDED LOWER CLOUDS IN KCOS TAF AS NORTH WIND MAY KEEP
CLOUDS JUST NORTH OF THE AIRPORT. ON TUE...EXPECT WIDESPREAD TSRA
ALL AREAS...WITH EARLY STORM INITIATION OVER THE MOUNTAINS BY 18Z.
BY MID TO LATE AFTERNOON...MTS WILL BE OBSCURED AND MVFR CONDITIONS
WITH THUNDERSTORMS WILL BE POSSIBLE AT ALL TAF SITES.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS PUEBLO CO
305 PM MDT MON AUG 25 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM MDT MON AUG 25 2014
CURRENTLY...COLD FRONT HAS BECOME STATIONARY NEAR THE NM BORDER
THIS AFTERNOON...AND WILL LIKELY DRIFT BACK NORTHWARD TOWARD THE
ARKANSAS RIVER BY 00Z. CONVECTION OVER THE MOUNTAINS AND ALONG THE
RATON MESA HAS BEEN RELATIVELY WEAK SO FAR AS STORMS HAVE YET TO
TAP DEEPER INSTABILITY NEAR THE KS BORDER AND FARTHER NORTH NEAR THE
PALMER DIVIDE. WITH COOL AIR SLIGHTLY DEEPER THAN EXPECTED...APPEARS
HIGH TEMPS WILL END UP JUST SHY OF FORECAST READINGS.
TONIGHT...MESOSCALE MODELS CONTINUE TO POINT TO AREAS ALONG AND
NORTH OF THE PALMER DIVIDE HAVING THE BEST CHANCE FOR STRONG/SEVERE
CONVECTION...THOUGH LATEST HRRR HINTS AT SOME SOME BRIEF STRONGER
STORMS OVER THE FAR EASTERN PLAINS...AS FRONTAL BOUNDARY RETREATING
NORTHWARD PROVIDES SOME ENHANCED CONVERGENCE. WEAK SHORT WAVE...OVER
WRN CO CURRENTLY...WILL ALSO PROVIDE SOME UPWARD MOTION AS IT
CROSSES THE AREA THIS EVENING. BY MIDNIGHT...SUSPECT CONVECTION WILL
SHIFT NORTHEAST AND COALESCE INTO AN MCS OVER NWRN KS/SRN NEB...WITH
FAIRLY LARGE COLD POOL GIVING SURFACE FRONT A RENEWED SHOVE
SOUTHWARD THROUGH THE EASTERN PLAINS. WITH A GRADUAL INCREASE IN MID
LEVEL MOISTURE THROUGH THE NIGHT AND BOUNDARY MOVING BACK
SOUTHWARD...WILL ONLY GRADUALLY TAPER OFF POPS THROUGH THE
EVENING...WITH AT LEAST SOME ISOLATED TSRA POSSIBLE PAST MIDNIGHT.
TUESDAY.. UPPER LOW WILL CONTINUE TO SLOWLY PUSH EASTWARD THROUGH
THE GREAT BASIN...WITH STRENGTHENING S-SW FLOW AHEAD OF THE SYSTEM
PUSHING AN INCREASING AMOUNT OF TROPICAL MOISTURE NORTHWARD INTO
COLORADO. SURFACE FRONT WILL LIKELY STAY SOUTH OF THE ARKANSAS RIVER
THROUGH THE DAY...WITH E-SE FLOW PUSHING 55F-60F DEWPOINTS WESTWARD
TOWARD THE I-25 CORRIDOR. WITH MOISTURE PLENTIFUL...EXPECT EARLY
INITIATION OF CONVECTION WITH STORMS FIRING OVER THE MOUNTAINS
BEFORE 18Z AND SPREADING QUICKLY TO LOWER ELEVATIONS BY 21Z. MAIN
THREAT TOMORROW OVER ALL AREAS WILL BE HEAVY RAINFALL...THOUGH WITH
CAPES OVER 1000 J/KG AND 0-6KM SHEAR OF 30-40 KTS...A SEVERE STORM
OR TWO IS POSSIBLE ON THE PLAINS MAINLY ALONG AND NORTH OF THE
ARKANSAS RIVER. ALL IN ALL...IT LOOKS LIKE A VERY WET DAY OVER MUCH
OF SOUTHERN COLORADO...AND WITH CLOUDS AND PRECIP FAIRLY QUICK TO
DEVELOP...MAX TEMPS SHOULD COOL AT LEAST A FEW DEGF VERSUS MON
READINGS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 305 PM MDT MON AUG 25 2014
TUESDAY NIGHT THROUGH FRIDAY...LATEST RUNS OF THE NAM...GFS AND EC
MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE PROGRESSION OF THE UPPER
TROUGH ACROSS THE REGION THROUGH THIS WEEK. TUE EVENING THE TROUGH
WILL BE POISED OVER NV AND UT...CONTINUING TO DRAW A STRONG MOISTURE
PLUME UP ACROSS THE 4 CORNERS AND INTO CO. THE TROUGH STEADILY
MARCHES TO THE EAST ACROSS COLORADO THROUGH WED AND THU...WITH THE
TROUGH AXIS FINALLY REACHING THE OK AND TX PANHANDLES BY FRI
MORNING. A GOOD AMOUNT OF MOISTURE...COUPLED WITH AVAILABLE DYNAMICS
AND A COLD FRONT WED EVE WILL PROVIDE FOR WIDESPREAD CONVECTION
CHANCES THROUGH THE PERIOD...WITH PCPN FINALLY TAPERING OFF FRI
MORNING. LOOK FOR SCATTERED POPS FOR MUCH OF THE AREA TUE EVE AND
AGAIN WED EVE THROUGH THU...WITH PCPN LIKELY OVER THE MTS. TEMPS ARE
EXPECTED TO REMAIN COOLER THROUGH FRI WITH MAX TEMPS IN THE UPPER
70S AND 80S FOR THE PLAINS...AND 60S AND 70S FOR THE HIGH VALLEYS.
SATURDAY THROUGH MONDAY...AS THE TROUGH EXITS TO THE EAST...A RIDGE
OF HIGH PRESSURE BUILDS OVER THE SW US. THIS WILL HELP A DRYING AND
WARMING TREND TO TAKE HOLD OVER THE WEEKEND AND INTO THE FIRST PART
OF THE NEXT WORK WEEK. PCPN CHANCES ARE FORECAST TO BE RESTRICTED TO
JUST ISOLATED DIURNAL ACTIVITY OVER THE HIGHER TERRAIN...AND TEMPS
WILL CLIMB BACK UP INTO THE 80S NEARING 90 F FOR THE PLAINS...AND
INTO THE 80S FOR THE HIGH VALLEYS. MOORE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 305 PM MDT MON AUG 25 2014
TSRA DEVELOPING OVER THE MOUNTAINS WILL CONTINUE TO SPREAD TO LOWER
ELEVATIONS THIS AFTERNOON...WITH STORMS NEAR KCOS AND KPUB IN THE
22Z-02Z PERIOD...AND AROUND KALS 22Z-01Z. WITH MORE MOISTURE
AVAILABLE TODAY...EXPECT LOWER CLOUD BASES AND RESTRICTED VISIBILITY
UNDER THE STRONGEST STORMS...AND LOCAL MVFR/BRIEF IFR CONDITIONS
WILL BE POSSIBLE. STORMS WILL GRADUALLY SHIFT INTO NORTHEAST
COLORADO THIS EVENING AND OVERNIGHT...WITH A COLD FRONT AND SHIFT TO
NORTHEAST WINDS PUSHING SOUTHWARD ACROSS THE PLAINS AFTER 00Z. MAY
SEE SOME IFR STRATUS ALONG THE PALMER DIVIDE BY 12Z TUE...BUT
HAVEN`T INCLUDED LOWER CLOUDS IN KCOS TAF AS NORTH WIND MAY KEEP
CLOUDS JUST NORTH OF THE AIRPORT. ON TUE...EXPECT WIDESPREAD TSRA
ALL AREAS...WITH EARLY STORM INITIATION OVER THE MOUNTAINS BY 18Z.
BY MID TO LATE AFTERNOON...MTS WILL BE OBSCURED AND MVFR CONDITIONS
WITH THUNDERSTORMS WILL BE POSSIBLE AT ALL TAF SITES.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS MIAMI FL
312 PM EDT MON AUG 25 2014
.DISCUSSION...A BACKDOOR TROUGH IS MOVING SOUTHWEST ACROSS THE
LOCAL AREA THIS AFTERNOON, BRINGING A SURGE IN MOISTURE ALONG
WITH IT. THIS HAS CAUSED SCATTERED FAST MOVING SHOWERS AND JUST A
FEW TSTORMS TO AFFECT SOUTH FL. ACTIVITY COULD BECOME SLIGHTLY
MORE FOCUSED ALONG THE GULF COAST OVER THE NEXT FEW HR. MAIN
IMPACTS WILL BE BRIEF HEAVY DOWNPOURS, GUSTY WINDS AND LIGHTNING
STRIKES...THOUGH THERE HAVE NOT BEEN MANY SO FAR TODAY.
THE TROUGH WILL MOVE SOUTH OF THE AREA TONIGHT AS CRISTOBAL
DISTANCES ITSELF FROM THE BAHAMAS. NE WINDS WILL INCREASE BEHIND
IT ALONG WITH SIGNIFICANT DRYING ALOFT. IN FACT...GOES SOUNDER
DATA SHOWS PWAT NOW AT AROUND 2 INCHES OVER SOUTH FL...BUT ONLY
ABOUT 1.25 INCHES MOVING INTO NORTHEAST FL AND INTO THE ATLANTIC
OFF EAST CENTRAL FL. THIS LOWER PWAT AIR WILL MOVE SOUTHWARD AND
OVER THE AREA TOMORROW (PUTTING US IN THE LOWER 25TH PERCENTILE
FOR THIS TIME OF THE YEAR)...LEADING TO LESS CONVECTIVE ACTIVITY
THAN NORMAL FOR SUMMERTIME. HAVE ONLY GONE WITH SLIGHT CHANCE POPS
TOMORROW WITH NO TSTORMS EXPECTED. HARD TO GET MUCH "FEEL" CHANGE
TO THE AIRMASS THOUGH GIVEN WINDS BLOWING OVER OUR UPPER 80 TO
NEAR 90 DEGREE WATERS. STILL...DEWPOINTS ARE FORECAST TO FALL INTO
THE LOWER 70S ATLANTIC COAST AND NEAR 70F INTERIOR- GULF COAST
WHICH IS BETTER THAN THE UPPER 70-DEGREE DEWPOINTS CURRENTLY IN
PLACE THOUGH! THIS "REPRIEVE" WON`T LAST LONG WITH MOISTURE
RECOVERY BEGINNING WEDNESDAY WITH A RETURN TO A MORE TYPICAL
SUMMERTIME REGIME -- HOT,HUMID WITH SCATTERED AFTERNOON
THUNDERSTORMS EACH DAY THROUGH WEEK`S END. /GREGORIA
&&
.MARINE...A SMALL CRAFT ADVISORY WILL BE IN EFFECT FOR THE PALM
BEACH AND OFF SHORE GULF WATERS BEGINNING AT 8 PM THIS EVENING AND
CONTINUING THROUGH THE NIGHT FOR NE WINDS SUSTAINED NEAR 20 KT.
SEAS IN THE GULF STREAM WILL BUILD TO NEAR 7 FEET OVERNIGHT IN
RESPONSE. THE SCA MAY NEED TO BE EXTENDED IN TIME FOR THE PALM
BEACH WATERS DUE TO HAZARDOUS GULF STREAM SEAS. WINDS/SEAS WILL
THEN SUBSIDE MID-LATE WEEK. /GREGORIA
&&
.AVIATION...SCATTERED SHOWERS AND A FEW ISOLATED THUNDERSTORMS CONTINUE
TO PUSH SOUTH ACROSS THE AREA THIS AFTERNOON. LATEST HRRR DEPICTS
ADDITIONAL SHOWERS THROUGH THE REST OF THE DAY WITHOUT ROBUST
CONVECTIVE DEVELOPMENT. THEREFORE REMOVED VCTS MENTION FROM ALL
SITES EXCEPT FOR KAPF. HOWEVER...CANNOT RULE OUT AN ISOLATED TSRA
TO BRIEFLY AFFECT A TAF SITE THROUGH THE EVENING. WINDS HAVE BEGUN
TO TURN MORE NORTHEASTERLY FROM KOPF SOUTHWARD AND SHOULD PREVAIL
AROUND 10 KNOTS THROUGH THE NIGHT. /CD
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 90 78 90 / 20 20 20 30
FORT LAUDERDALE 81 91 80 91 / 20 20 20 30
MIAMI 80 91 79 91 / 20 20 20 40
NAPLES 78 92 77 91 / 20 20 10 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT TUESDAY
FOR AMZ650-670.
GM...SMALL CRAFT ADVISORY FOR WINDS FROM 8 PM THIS EVENING TO 8 AM
EDT TUESDAY FOR GMZ676.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
642 PM EDT MON AUG 25 2014
.SYNOPSIS...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL
DIRECT DRY AIR INTO THE AREA THROUGH THE END OF THE WORK WEEK.
TEMPERATURES WILL BE NEAR NORMAL THROUGH TUESDAY...FOLLOWED BY A
WARMING TREND FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A LARGE UPPER LEVEL RIDGE EXTENDED FROM THE SOUTHERN PLAINS TO
NEW ENGLAND WITH AN UPPER TROUGH WELL OFF THE EAST COAST. SURFACE
HIGH PRESSURE STRETCHED FROM THE NORTHEASTERN STATES ACROSS THE
CAROLINAS AND GEORGIA.
MOIST ONSHORE FLOW COULD BRING AN AREA OF CLOUDS ACROSS THE AREA
OVERNIGHT. AFTERNOON SATELLITE LOOP SHOWS SOME SCATTERED/BROKEN
AROUND 5K FT MOVING FROM THE PEE DEE INTO THE CENTRAL/EASTERN
MIDLANDS. BOTH THE RUC AND NAM INDICATE THIS MOISTURE. MODEL TIME
SECTIONS ALSO SHOW A 20 TO 25 KT LOW LEVEL JET AFTER MIDNIGHT AND
EXPECT THIS TO KEEP WINDS UP SLIGHTLY OVER LAND AND ALSO OVER THE
AREA LAKES. KEPT OVERNIGHT LOWS IN LINE WITH GUIDANCE...RANGING
THROUGH THE 60S GIVEN BOUNDARY LAYER MIXING AND PERIOD OF CLOUDS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT WILL BE IN CONTROL
ACROSS THE REGION. THE AIR MASS WILL BE DRY WITH PWAT AT OR BELOW
ONE INCH. H850 TEMPERATURES WARM A COUPLE OF DEGREES...RESULTING
IN AFTERNOON HIGHS IN THE 85 TO 90 DEGREE RANGE UNDER SUNNY SKIES.
GOOD RADIATIONAL COOLING IN DRY AIR MASS WILL ALLOW TEMPERATURES
TO COOL INTO THE LOW TO MID 60S AS INDICATED BY GUIDANCE
CONSENSUS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH FRIDAY AS AN UPPER
RIDGE BUILDS OVER THE SOUTHEAST. THE UPPER RIDGE WEAKENS A BIT OVER
THE WEEKEND AS LOW-LEVEL MOISTURE INCREASES...BUT THE RIDGE
STRENGTHENS AGAIN BY MONDAY. EXPECT A CHANCE OF SHOWERS AND
THUNDERSTORMS SATURDAY AND SUNDAY WITH A LESSER CHANCE MONDAY.
DAYTIME HIGH TEMPERATURES WILL INCREASE TO ABOVE NORMAL THROUGH
FRIDAY...AND NEAR NORMAL SATURDAY THROUGH MONDAY. OVERNIGHT LOW
TEMPERATURES WILL BE BELOW NORMAL WEDNESDAY AND THURSDAY...AND NEAR
NORMAL SATURDAY THROUGH MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE RIDGING INTO THE AREA FROM THE NORTH WILL DOMINATE
THROUGH THE TAF PERIOD. MOISTURE FROM THE ATLANTIC IN THE
NORTHEAST FLOW WILL AFFECT THE REGION BUT EXPECT THE ASSOCIATED
CLOUDINESS WILL BE MAINLY SCATTERED AND BE AROUND 4000 FEET.
OBSERVATION TRENDS...THE GFS AND NAM MOS...AND THE SREF GUIDANCE
MAINTAIN VFR CONDITIONS. MIXING AND THE DRY NEAR-SURFACE LAYER
SHOULD HELP PREVENT FOG DURING THE EARLY MORNING HOURS. USED THE
GFS AND NAM MOS FOR THE WIND FORECAST.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
77
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
630 PM EDT MON AUG 25 2014
.SYNOPSIS...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL
DIRECT DRY AIR INTO THE AREA THROUGH THE END OF THE WORK WEEK.
TEMPERATURES WILL BE NEAR NORMAL THROUGH TUESDAY...FOLLOWED BY A
WARMING TREND FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A LARGE UPPER LEVEL RIDGE EXTENDED FROM THE SOUTHERN PLAINS TO
NEW ENGLAND WITH AN UPPER TROUGH WELL OFF THE EAST COAST. SURFACE
HIGH PRESSURE STRETCHED FROM THE NORTHEASTERN STATES ACROSS THE
CAROLINAS AND GEORGIA. WEAK COLD/DRY ADVECTION THIS AFTERNOON WITH
PWAT BELOW ONE INCH. SURFACE PRESSURE GRADIENT MODERATELY TIGHT SO
EXPECT SOME GUSTY NORTHEAST WINDS THIS AFTERNOON. TEMPERATURES
WILL BE SEASONABLE WITH HIGHS RANGING THROUGH THE 80S UNDER SUNNY
SKIES.
MOIST ONSHORE FLOW COULD BRING AN AREA OF CLOUDS ACROSS THE AREA
OVERNIGHT. BOTH THE RUC AND NAM INDICATE THIS MOISTURE. KEPT
OVERNIGHT LOWS IN LINE WITH GUIDANCE...RANGING THROUGH THE 60S
GIVEN BOUNDARY LAYER MIXING AND PERIOD OF CLOUDS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT WILL BE IN CONTROL
ACROSS THE REGION. THE AIR MASS WILL BE DRY WITH PWAT AT OR BELOW
ONE INCH. H850 TEMPERATURES WARM A COUPLE OF DEGREES...RESULTING
IN AFTERNOON HIGHS IN THE 85 TO 90 DEGREE RANGE UNDER SUNNY SKIES.
GOOD RADIATIONAL COOLING IN DRY AIR MASS WILL ALLOW TEMPERATURES
TO COOL INTO THE LOW TO MID 60S AS INDICATED BY GUIDANCE
CONSENSUS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH FRIDAY AS AN UPPER
RIDGE BUILDS OVER THE SOUTHEAST. THE UPPER RIDGE WEAKENS A BIT OVER
THE WEEKEND AS LOW-LEVEL MOISTURE INCREASES...BUT THE RIDGE
STRENGTHENS AGAIN BY MONDAY. EXPECT A CHANCE OF SHOWERS AND
THUNDERSTORMS SATURDAY AND SUNDAY WITH A LESSER CHANCE MONDAY.
DAYTIME HIGH TEMPERATURES WILL INCREASE TO ABOVE NORMAL THROUGH
FRIDAY...AND NEAR NORMAL SATURDAY THROUGH MONDAY. OVERNIGHT LOW
TEMPERATURES WILL BE BELOW NORMAL WEDNESDAY AND THURSDAY...AND NEAR
NORMAL SATURDAY THROUGH MONDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE RIDGING INTO THE AREA FROM THE NORTH WILL DOMINATE
THROUGH THE TAF PERIOD. MOISTURE FROM THE ATLANTIC IN THE
NORTHEAST FLOW WILL AFFECT THE REGION BUT EXPECT THE ASSOCIATED
CLOUDINESS WILL BE MAINLY SCATTERED AND BE AROUND 4000 FEET.
OBSERVATION TRENDS...THE GFS AND NAM MOS...AND THE SREF GUIDANCE
MAINTAIN VFR CONDITIONS. MIXING AND THE DRY NEAR-SURFACE LAYER
SHOULD HELP PREVENT FOG DURING THE EARLY MORNING HOURS. USED THE
GFS AND NAM MOS FOR THE WIND FORECAST.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
318 PM EDT MON AUG 25 2014
.SYNOPSIS...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL
DIRECT DRY AIR INTO THE AREA THROUGH THE END OF THE WORK WEEK.
TEMPERATURES WILL BE NEAR NORMAL THROUGH TUESDAY...FOLLOWED BY A
WARMING TREND FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A LARGE UPPER LEVEL RIDGE EXTENDED FROM THE SOUTHERN PLAINS TO
NEW ENGLAND WITH AN UPPER TROUGH WELL OFF THE EAST COAST. SURFACE
HIGH PRESSURE STRETCHED FROM THE NORTHEASTERN STATES ACROSS THE
CAROLINAS AND GEORGIA. WEAK COLD/DRY ADVECTION THIS AFTERNOON WITH
PWAT BELOW ONE INCH. SURFACE PRESSURE GRADIENT MODERATELY TIGHT SO
EXPECT SOME GUSTY NORTHEAST WINDS THIS AFTERNOON. TEMPERATURES
WILL BE SEASONABLE WITH HIGHS RANGING THROUGH THE 80S UNDER SUNNY
SKIES.
MOIST ONSHORE FLOW COULD BRING AN AREA OF CLOUDS ACROSS THE AREA
OVERNIGHT. BOTH THE RUC AND NAM INDICATE THIS MOISTURE. KEPT
OVERNIGHT LOWS IN LINE WITH GUIDANCE...RANGING THROUGH THE 60S
GIVEN BOUNDARY LAYER MIXING AND PERIOD OF CLOUDS.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT WILL BE IN CONTROL
ACROSS THE REGION. THE AIR MASS WILL BE DRY WITH PWAT AT OR BELOW
ONE INCH. H850 TEMPERATURES WARM A COUPLE OF DEGREES...RESULTING
IN AFTERNOON HIGHS IN THE 85 TO 90 DEGREE RANGE UNDER SUNNY SKIES.
GOOD RADIATIONAL COOLING IN DRY AIR MASS WILL ALLOW TEMPERATURES
TO COOL INTO THE LOW TO MID 60S AS INDICATED BY GUIDANCE
CONSENSUS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH FRIDAY AS AN UPPER
RIDGE BUILDS OVER THE SOUTHEAST. THE UPPER RIDGE WEAKENS A BIT OVER
THE WEEKEND AS LOW-LEVEL MOISTURE INCREASES...BUT THE RIDGE
STRENGTHENS AGAIN BY MONDAY. EXPECT A CHANCE OF SHOWERS AND
THUNDERSTORMS SATURDAY AND SUNDAY WITH A LESSER CHANCE MONDAY.
DAYTIME HIGH TEMPERATURES WILL INCREASE TO ABOVE NORMAL THROUGH
FRIDAY...AND NEAR NORMAL SATURDAY THROUGH MONDAY. OVERNIGHT LOW
TEMPERATURES WILL BE BELOW NORMAL WEDNESDAY AND THURSDAY...AND NEAR
NORMAL SATURDAY THROUGH MONDAY.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH THE 24-HOUR TAF
PERIOD. SURFACE HIGH PRESSURE CONTINUES BUILDING DOWN THE EASTERN
SEABOARD...COUPLED WITH AN UPPER RIDGE OVERHEAD. CLEAR SKIES THIS
AFTERNOON. MODELS INDICATE AN INCREASE IN CLOUDS 4-6KFT OVERNIGHT
IN MOIST ONSHORE FLOW.
NORTHEAST WINDS 10 TO 15 KNOTS WITH GUST NEAR 20 KNOTS THIS
AFTERNOON WILL DIMINISH WITH SUNSET.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
210 PM EDT MON AUG 25 2014
.SYNOPSIS...
HIGH PRESSURE RIDGING INTO THE FORECAST AREA FROM THE NORTH WILL
DIRECT DRY AIR INTO THE AREA THROUGH THE END OF THE WORK WEEK.
TEMPERATURES WILL BE NEAR NORMAL THROUGH TUESDAY...FOLLOWED BY A
WARMING TREND FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LARGE UPPER LEVEL RIDGE EXTENDED FROM THE SOUTHERN PLAINS TO
NEW ENGLAND WITH AN UPPER TROUGH WELL OFF THE EAST COAST. SURFACE
HIGH PRESSURE STRETCHED FROM THE NORTHEASTERN STATES ACROSS THE
CAROLINAS AND GEORGIA. WEAK COLD/DRY ADVECTION THIS AFTERNOON WITH
PWAT BELOW ONE INCH. SURFACE PRESSURE GRADIENT MODERATELY TIGHT SO
EXPECT SOME GUSTY NORTHEAST WINDS THIS AFTERNOON. TEMPERATURES
WILL BE SEASONABLE WITH HIGHS RANGING THROUGH THE 80S UNDER SUNNY
SKIES.
MOIST ONSHORE FLOW COULD BRING AN AREA OF CLOUDS ACROSS THE AREA
OVERNIGHT. BOTH THE RUC AND NAM INDICATE PWAT INCREASING TO NEAR
2.00 INCHES WITH AN INCREASE IN H850 MOISTURE. KEPT OVERNIGHT LOWS
IN LINE WITH GUIDANCE...RANGING THROUGH THE 60S GIVEN BOUNDARY LAYER
MIXING AND PERIOD OF CLOUDS.
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
HIGH PRESSURE BOTH AT THE SURFACE AND ALOFT WILL BE IN CONTROL
ACROSS THE REGION. THE AIR MASS WILL BE DRY WITH PWAT AT OR BELOW
ONE INCH. H850 TEMPERATURES WARM A COUPLE OF DEGREES...RESULTING
IN AFTERNOON HIGHS IN THE 85 TO 90 DEGREE RANGE UNDER SUNNY SKIES.
GOOD RADIATIONAL COOLING IN DRY AIRMASS WILL ALLOW TEMPERATURES TO
COOL INTO THE LOW TO MID 60S AS INDICATED BY GUIDANCE CONSENSUS.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH FRIDAY AS AN UPPER
RIDGE BUILDS OVER THE SOUTHEAST. THE UPPER RIDGE WEAKENS A BIT OVER
THE WEEKEND AS LOW-LEVEL MOISTURE INCREASES...BUT THE RIDGE
STRENGTHENS AGAIN BY MONDAY. EXPECT A CHANCE OF SHOWERS AND
THUNDERSTORMS SATURDAY AND SUNDAY WITH A LESSER CHANCE MONDAY.
DAYTIME HIGH TEMPERATURES WILL INCREASE TO ABOVE NORMAL THROUGH
FRIDAY...AND NEAR NORMAL SATURDAY THROUGH MONDAY. OVERNIGHT LOW
TEMPERATURES WILL BE BELOW NORMAL WEDNESDAY AND THURSDAY...AND NEAR
NORMAL SATURDAY THROUGH MONDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS EXPECTED TO CONTINUE THROUGH THE 24 HOUR TAF PERIOD.
SURFACE HIGH PRESSURE CONTINUES BUILDING DOWN THE EASTERN
SEABOARD...COUPLED WITH AN UPPER RIDGE OVERHEAD. CLEAR SKIES THIS
AFTERNOON. MODELS INDICATE AN INCREASE IN CLOUDS 4-6KFT OVERNIGHT
IN MOIST ONSHORE FLOW.
NORTHEAST WINDS 10 TO 15 KNOTS WITH GUST NEAR 20 KNOTS THIS
AFTERNOON WILL DIMINISH WITH SUNSET.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
317 PM CDT MON AUG 25 2014
.DISCUSSION...
315 PM CDT
SHORT TERM...THROUGH EARLY TUESDAY MORNING...
FOR THE REMAINDER OF THE AFTERNOON...MAIN FOCUS WILL CONTINUE TO BE
2 LINES OF THUNDERSTORMS...ONE MOVING THROUGH NWRN IL AND ANOTHER
MOVING THROUGH NWRN IN AND ECNTRL IL. THESE LINES ARE PRODUCING
STRONG TO OCNLY SVR TS...WITH THE PRIMARY THREAT BEING WIND GUSTS
TO 60 MPH AND TORRENTIAL DOWNPOURS. THE TREND WITH TIME SHOULD BE
FOR THE LINE OVER NWRN IL TO BEGIN TO WEAKEN AS IT MOVES INTO AN
AIRMASS OVER NERN IL WHICH HAS BEEN WORKED OVER BY EARLIER
CONVECTION. THE LINE ACROSS NWRN IN INTO ECNTRL IL SHOULD MAINTAIN
SOME STRENGTH AS IT CONTINUES TO PUSH SEWD. LATEST RADAR IMAGERY
SHOWS A DISTINCT OUTFLOW BOUNDARY EXTENDING WEST FROM KANKAKEE TO
PERU WHICH COULD YET BE THE FOCUS FOR SOME ADDITIONAL THUNDERSTORM
DEVELOPMENT INTO THE EARLY EVENING HOURS. THUNDERSTORMS HAVE HAD A
HISTORY OF PRODUCING IN EXCESS OF 1 INCH IN 30 MINUTES...BUT SINCE
THEY HAVE BEEN PROGRESSIVE...SIGNIFICANT WIDESPREAD FLOODING IS NOT
ANTICIPATED...THOUGH LOCALLY HEAVY RAINFALL COULD PRODUCE URBAN ANS
SMALL STREAM TYPE FLOODING. EXPECT THAT THE POTENTIAL FOR ORGANIZED
THUNDERSTORMS SHOULD DIMINISH INTO EARLY THIS EVENING WITH THE
SETTING SUN AND LARGER SCALE SUBSIDENCE MOVES OVER THE AREA AS WEAK
SHORT WAVE RIDGING MOVES OVER THE AREA TONIGHT. AS THE THUNDERSTORM
ACTIVITY DIMINISHES THIS EVENING...PATCHY FOG AND WIDESPREAD
MISTY/MURKY CONDITIONS WILL SET UP. WHILE WIDESPREAD DENSE FOG IS
NOT LIKELY DUE TO PERSISTENT DEBRIS CLOUD FROM EARLIER
CONVECTION...A VERY MOIST ENVIRONMENT WILL REMAIN IN PLACE...AND
COMBINED WITH LIGHT WINDS CONDITIONS WILL REMAIN MUGGY OVERNIGHT.
THE TEMPERATURE FORECAST FOR TODAY WAS DISRUPTED BY THE THUNDERSTORMS
AND EXTENSIVE CLOUD COVER OVER AREAS IMPACTED BY THE THUNDERSTORMS.
HOWEVER...LOCATIONS SOUTH OF A LINE FROM MIDWAY AIRPORT TO PERU
STILL SAW MAX HEAT INDICES IN EXCESS OF 100F WHILE LOCATIONS SOUTH
OF THE ILLINOIS/KANKAKEE RIVERS SAW HEAT INDICES APPROACH OR SLIGHTLY
EXCEED 110F. TEMPERATURES AND DEWPOINTS SHOULD REMAIN IN THE LOWER
TO MIDDLE 70S OVERNIGHT AS THERE WILL BE NO SGFNT CHANGE IN
AIRMASS. WITH OLD OUTFLOW BOUNDARIES HANGING AROUND THE AREA
OVERNIGHT...THERE WILL STILL BE SOME LOW CHANCES FOR ADDITIONAL
SHOWERS OR THUNDERSTORMS AS A WEAK COLD FRONT MOVES DOWN THE LAKE
AND INTO THE WARM...HUMID ENVIRONMENT.
KREIN
LONG TERM DISCUSSION COMING SOON...
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WINDS TURNING NE ARND 10-12KT...WITH AN OCCASIONAL GUSTS TO
20-25KT.
* WIND SPEEDS DIMINISH TO ARND 6-8KT LATE AFTN/EARLY EVE...THEN
TURN W/NW.
* POSSIBLE ADDTL ISOLATED TSRA OVERNIGHT/EARLY TUE MORNING.
* PATCHY FOG DEVELOPING AFT 04Z...MAY REDUCE VSBYS TO ARND 2-4SM.
WEST OF TAF SITES VSBYS COULD BE LOWER.
BEACHLER
//DISCUSSION...UPDATED 18Z...
SPOTTY SHOWERS AND THUNDERSTORMS HAVE CONTINUED TO DEVELOP ALONG
AN ORIGINAL OUTFLOW BOUNDARY ACROSS NORTHEAST IL. ADDTL SHRA/TSRA
HAVE DEVELOPED WEST OF TAF SITES...WITH A FEW STRONGER STORMS
CAPABLE OF PRODUCING WIND GUSTS TO 40KTS THIS AFTN. CONCERN IS
THAT A WEAK BOUNDARY SLIDING SOUTH AND A LACK OF A GRADIENT...WILL
ONLY PROLONG THE NORTHEAST WINDS AT ORD/MDW. MEANWHILE FURTHER
WEST AT RFD/DPA THE WINDS SHUD BE ABLE TO TURN NW/W ARND 20-21Z.
WILL CONTINUE TO MENTION VCTS THRU 23Z...AND IF ADDTL STORMS ARE
ABLE TO DEVELOP WE WILL LIKELY NEED TO ADJUST WITH A TEMPO BUT
COVERAGE IS NOT EXPECTED TO BE THERE. THEN LATE THIS EVENING
GUIDANCE IS SUGGESTING THE WINDS WILL BECOME LGT FROM THE NW ARND
5-8KT. THE CONCERN THEN WILL TURN TOWARDS THE LOW CIGS BUT ALSO
THE POTENTIAL FOR PATCHY FOG TO DEVELOP GIVEN HOW MOIST THE
ENVIRONMENT WILL REMAIN OVERNIGHT. FOG MAY BEGIN TO DISSIPATE AFT
DAYBREAK TUE...THEN GUIDANCE SUGGESTS THE WINDS WILL TRY TO TURN
NW WITH SPEEDS ARND 8-11KT.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN TSRA REMAINING ISOLATED...LOW CONFIDENCE IN
PRECISE TIMING/INTENSITY AT TAF SITES.
* HIGH CONFIDENCE IN WINDS REMAINING NORTHEAST THRU 22Z...THEN LOW
CONFIDENCE IN TIMING OF WINDS TURNING NW LATE AFTN/EARLY EVE.
* MEDIUM CONFIDENCE IN PATCHY FOG DEVELOPING.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
* TUESDAY NIGHT...TSRA LIKELY.
* WEDNESDAY THROUGH SUNDAY...CHANCE OF TSRA.
&&
.MARINE...
243 AM...LOW PRESSURE OVER SOUTHERN MANITOBA WILL MOVE ACROSS
NORTHERN ONTARIO TODAY AND TONIGHT REACHING JAMES BAY TUESDAY
MORNING. A TRAILING COLD FRONT WILL SLOWLY SAG SOUTHEAST ACROSS
THE WESTERN LAKES AND REACH NORTHERN LAKE MICHIGAN BY DAYBREAK
TUESDAY MORNING. THIS FRONT WILL THEN CONTINUE SOUTH ACROSS LAKE
MICHIGAN TUESDAY AND EVENTUALLY STALL NEAR OR JUST SOUTH OF THE
LAKE WEDNESDAY INTO THURSDAY. AHEAD OF THIS FRONT...SOUTH TO
SOUTHEAST WINDS 10-20KTS WILL GRADUALLY SHIFT MORE SOUTHWESTERLY
LATER TODAY AND THIS EVENING. A FEW HIGHER GUSTS ARE POSSIBLE BUT
THE TIGHTEST PORTION OF THE GRADIENT PASSES NORTH OF THE LAKE.
HIGH PRESSURE WILL BUILD ACROSS THE NORTHERN PLAINS ON TUESDAY
AND THEN MOVE ACROSS THE NORTHERN LAKES WEDNESDAY. THIS MAY
STRENGTHEN THE GRADIENT A BIT ON THE SOUTHERN END OF THE LAKE
WITH A PROLONGED NORTHEAST FLOW IN THE 10-20KT RANGE POSSIBLE.
CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...HEAT ADVISORY...ILZ010-ILZ019-ILZ021-ILZ023-ILZ032-ILZ033-ILZ039
UNTIL 10 PM MONDAY.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
314 PM CDT Mon Aug 25 2014
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 312 PM CDT MON AUG 25 2014
Hot and very humid conditions are the rule across central Illinois
this afternoon, with 19z/2pm temperatures in the lower to middle 90s
across the board. Further north, clusters of thunderstorms have
developed along outflow boundaries from eastern Iowa across
northern Illinois. This convection is generally tracking eastward,
with a slight southeastward drift. High-res models are once again
handling the convection quite poorly, with the 2-hr HRRR forecast
completely missing the storms currently ongoing south of Chicago.
The Chicago storm complex will continue developing E/SE into
northwest Indiana over the next couple of hours. Meanwhile, we will
have to keep an eye on additional storms just north of Moline.
These cells will likely track E/SE along an outflow boundary evident
on satellite/radar imagery and should remain just north of the KILX
CWA. Have included a slight chance PoP along/northeast of a Henry
to Danville late this afternoon into the early evening in case they
develop a bit further southward.
A cold front currently analyzed across central Iowa will gradually
push eastward over the next 12 to 24 hours, reaching the northern
KILX CWA by Tuesday morning. Many of the 12z models show little or
no convection with the boundary overnight, but have included low
chance PoPs along/northwest of a Rushville to Bloomington line as
the front encounters a very moist airmass. Aside from any scattered
convection that may develop, the potential for fog will once again
be an issue overnight. Light/variable winds along with dewpoint
pooling along the boundary will favor fog, but increased mid/high
clouds may tend to mitigate it somewhat. Based on an unchanged
airmass and persistence from the past several nights, have included
patchy fog in the forecast after midnight.
Any fog will dissipate early Tuesday morning, followed by partly to
mostly sunny conditions across the southern half of the CWA.
Further north in closer proximity to the nearly stationary frontal
boundary, mostly cloudy skies and scattered convection will keep
temps slightly cooler than they have been recently. High temps on
Tuesday will range from the upper 80s north to the middle 90s
along/south of I-70. Due to the slightly cooler temps, heat index
readings across the north may not reach advisory criteria. May need
to drop the advisory for the Peoria area northward, as heat index
values will likely remain in the 95 to 100 degree range on Tuesday.
&&
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 312 PM CDT MON AUG 25 2014
A frontal boundary will become somewhat stationary over the area and
is forecast to remain there through the rest of the week and into
the weekend. This will become the focus for thunderstorms throughout
the period. Thunderstorms will not be continuous throughout the
period, but trying to time when the dry, or drier, periods is going
to be is the main forecast challenge. Due to the difficulty of
timing the precip periods and the dry periods during the medium and
long ranges of the forecast, best to just have chance pcpn through
the period over the whole area. Will have likely pops in the north
third of the CWA for Tue night, but remainder of the forecast will
just be chance across the area.
With the frontal boundary getting into the area, relatively cooler
air will advect into the area. Temperatures will gradually drop back
to around normal, which is middle to upper 80s, by the weekend.
However, with all the moisture forecasted over the area, muggy/humid
conditions will continue through the period.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 1248 PM CDT MON AUG 25 2014
Mostly sunny skies will prevail across central Illinois today, as
convection remains along/north of the I-80 corridor. Latest
satellite imagery shows clear skies across much of the area, with
just FEW-SCT diurnal clouds developing near KBMI and KCMI. Cold
front currently analyzed across central Iowa will drop
southeastward tonight, eventually settling into north-central
Illinois by Tuesday morning. With boundary approaching, winds will
go light/variable, once again setting up the potential for fog
overnight. Forecast soundings and numeric guidance support fog
development, so have included reduced visbys of 3 to 5 miles
between 08z and 14z. Am not expecting much in the way of
thunderstorm development through 18z, although have introduced a
mid-level cloud deck at KPIA as the front arrives late tonight
into Tuesday morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING until 7 PM CDT Tuesday FOR ILZ042-047>054-
056-061>063-066>068-071>073.
HEAT ADVISORY until 7 PM CDT Tuesday FOR ILZ027>031-036>038-040-
041-043>046-055-057.
&&
$$
SHORT TERM...BARNES
LONG TERM...AUTEN
AVIATION...BARNES
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
228 PM EDT MON AUG 25 2014
.SYNOPSIS...
ISSUED AT 1056 AM EDT MON AUG 25 2014
HOT AND MUGGY CONDITIONS ACROSS THE REGION TODAY INTO TONIGHT.
DEWPOINTS IN THE LOWER 70S WILL CREATE MUGGY CONDITIONS AS HIGH
PRESSURE RETAINS ITS INFLUENCE OVER US. A FRONTAL SYSTEM TO THE
WEST COULD INTRODUCE SOME RAIN TO THE NORTHERN PORTION OF THE
REGION TONIGHT AS IT APPROACHES. HIGH TEMPERATURES TODAY WILL BE IN
THE UPPER 80S TO AROUND 90 WITH THE HEAT INDEX IN THE 90S TO NEAR 100.
LOW TEMPERATURES TONIGHT WILL RANGE FROM THE UPPER 60S NEAR THE
OHIO RIVER TO THE LOWER 70S IN SOUTHERN MICHIGAN.
&&
.UPDATE...
ISSUED AT 1242 PM EDT MON AUG 25 2014
FOCUS FOR THE REMAINDER OF THE AFTERNOON WILL CENTER ON CONVECTIVE
POTENTIAL AND HEAT. RESIDUAL OUTFLOW BOUNDARY FROM UPSTREAM
CONVECTION HAS ALLOWED FOR RENEWED THUNDERSTORM DEVELOPMENT ACROSS
NORTHEAST ILLINOIS. REMNANT OUTFLOW/CONVECTIVE VORT FROM UPSTREAM
CONVECTION WILL HAVE PLENTY OF DOWNSTREAM INSTABILITY TO WORK THIS
AFTERNOON WITH INDICATIONS IN RUC SHORT TERM PROGS OF 3-4K J/KG OF
100 HPA MLCAPES WORKING INTO WESTERN PORTIONS OF THE AREA. DEEP
LAYER SHEAR IS WEAK...BUT GIVEN MAGNITUDE OF INSTABILITY WILL HAVE
TO MONITOR FOR POSSIBILITY OF ISOLATED STRONG/SEVERE STORMS THIS
AFTERNOON. WITH EARLY AFTERNOON UPDATE...WILL GO AHEAD AND MAKE
SOME SOUTHEAST EXPANSION OF SLIGHT CHANCE AND PERHAPS RAISE POPS A
BIT IN THE FAR NORTHWEST DUE TO APPROACH OF OUTFLOW BOUNDARY.
TEMPERATURES/DEW POINTS APPEAR TO BE IN GOOD SHAPE WITH PEAK
AFTERNOON HEAT INDICES STILL LIKELY TO REACH INTO THE UPPER 90S
ACROSS THE WEST. WILL CONTINUE TO GO WITH CURRENT SPS FOR THIS
AFTERNOON TO HIGHLIGHT HAZARDOUS CONDITIONS ASSOCIATED WITH THE
HEAT/HUMIDITY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM EDT MON AUG 25 2014
FOCUS OF PERIOD WILL BE TWO FOLD...TEMPERATURES/HEAT INDEX ISSUES AND
CHANCES FOR STORMS.
WARM AND MUGGY CONDITIONS WERE IN PLACE ACROSS THE AREA WITH
TEMPERATURES IN THE 70S AND DEWPOINTS IN THE UPPER 60S NE TO LOWER
70S SW WITH MOST UNSTABLE CAPE VALUES IN THE 500 TO 1500 J/KG RANGE.
WITH NO REAL TRIGGER ACROSS THE AREA NO SHOWERS/STORMS HAVE FORMED
THUS FAR. MAIN FOCUS FOR STORMS HAS BEEN FROM NORTHERN WISCONSIN
INTO PORTIONS OF CENTRAL IOWA WHERE 30 TO 35 KT LOW LEVEL JET WAS
AIDING IN DEVELOPMENT AND MAINTENANCE OF A BROKEN LINE OF STRONG
TO LOCALLY SEVERE STORMS. HI RES MODELS ALL SUGGEST THIS LINE WILL
DROP SLOWLY SOUTHEAST BUT VARY IN HOW MUCH HOLD TOGETHER AS WE
APPROACH 12Z MON AND POINTS BEYOND. WOULD SEEM REASONABLE THAT
SOME SORT OF OUTFLOW BOUNDARY OR REMNANT SHOWERS/STORMS COULD
APPROACH NW AREAS THIS AFTERNOON AND THEN STALL SOMEWHERE TONIGHT
BEING REINFORCED SOMEWHAT BY SFC FRONT THAT WILL BE SINKING SOUTH.
ONLY CHANGE TO GRIDS WILL BE REORIENTATION OF SLGT CHC POPS TO
MORE OF A SW TO NE ORIENTATION. IF SUFFICIENT HEATING TAKES PLACE
AND PROGGED INSTABILITY IS AVAILABLE (SURFACE BASED CAPES IN
EXCESS OF 4000 J/KG IN A WEAKLY SHEAR ENVIRONMENT) THEN SOME
STRONGER STORMS COULD BE A CONCERN.
NOW FOR TEMPERATURES...THE WARM START TO THE MORNING SHOULD ALLOW
TEMPERATURES TO QUICKLY CLIMB INTO THE 80S BY NOON TIME AND POSSIBLY
CLOSE TO 90 IN WESTERN AREAS. DEWPOINTS IN WESTERN AREAS LOOK TO
CLIMB INTO THE MIDDLE 70S IN SOME SPOTS WHICH IF TEMPS DO APPROACH
90 WILL EDGE REAL CLOSE TO HEAT ADVISORY LEVELS (EVEN BRIEFLY TOUCH
IN FAR WEST). WILL HANDLE WITH HWO AND SPS FOR NOW AND LET DAY SHIFT
ASSESS THINGS AFTER SUNRISE AS TO EXTENT OF CLOUD COVER AND POSSIBLE
INFLUENCE FROM UPSTREAM CONVECTION. LOWS TONIGHT WILL DROP BACK INTO
THE UPR 60S TO LOWER 70S.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 404 AM EDT MON AUG 25 2014
LOW OVER SRN MANITOBA THIS MORNING EXPECTED TO LIFT NE INTO QUEBEC
TUESDAY WITH TRAILING CDFNT MOVG INTO OUR CWA. WK FORCING ALONG THE
FRONT COMBINED WITH SOME CAPPING ASSOCIATED WITH UPR RIDGE OVER THE
OH/MID MS VALLEY LIMITS TSTM POTENTIAL TO CHC DESPITE AT LEAST
MODERATE INSTABILITY IN PLACE OVER THE AREA. TEMPS WILL REMAIN ABOVE
NORMAL WITH HIGHS IN THE UPPER 80S AND PM HEAT INDEX READINGS IN THE
90S.
CDFNT EXPECTED TO SAG SOUTH INTO CENTRAL OH/IN TUE NGT. POTENTIAL
FOR TSTMS INCREASES A BIT IN THIS TIMEFRAME AS A SHRTWV CURRENTLY
OVER WRN CANADA MOVES TO THE UPR GRTLKS RESULTING IN MINOR HEIGHT
FALLS AS FAR SOUTH AS OUR CWA. WK CAA SHOULD ALLOW FOR LOWS TO FALL
INTO THE M-U60S ACROSS THE AREA.
RAIN CHANCES DIMINISH WED-WED NGT AS FRONT CONTS TO SAG SOUTH TO THE
OH VALLEY AND SFC HIGH MOVES ESE INTO THE UPR GRTLKS. TEMPS SHOULD
FALL BACK CLOSER TO NORMAL WITH HIGHS IN THE L80S AND LOWS IN THE
L-M60S.
FRONTAL SYSTEM EXPECTED TO LIFT BACK NORTH INTO OUR AREA THU-THU NGT
AS SFC HIGH MOVES TO THE MID ATLANTIC/NORTHEAST U.S.. DVLPG SPLIT
FLOW CUT-OFF LOW OVER THE WRN U.S. BY MID WEEK IS EXPECTED TO MOVE
SLOWLY EAST TO THE CENTRAL PLAINS FRIDAY AND INTO THE MID MS VALLEY
BY SUNDAY WHILE SFC BOUNDARY LINGERS OVER THE AREA... ENHANCING TSTM
POTENTIAL ACROSS OUR AREA OVER THE LABOR DAY WEEKEND... WHILE TEMPS
REMAIN CLOSE TO NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 200 PM EDT MON AUG 25 2014
AN OUTFLOW BOUNDARY ASSOCIATED WITH OVERNIGHT UPSTREAM CONVECTION
HAS BEEN A TRIGGER MECHANISM FOR SHOWERS AND THUNDERSTORMS ACROSS
NORTHEAST ILLINOIS AND SOUTHERN LOWER MICHIGAN. THIS BOUNDARY
SHOULD CONTINUE TO DROP INTO NORTH CENTRAL INDIANA BY 20Z. A
STRONGLY UNSTABLE ENVIRONMENT EXISTS ACROSS THE AREA...WITH MAIN
NEGATIVE FACTOR TO SOUTHEAST EXPANSION OF THE SHOWERS AND STORMS
IS BACKGROUND WEAK UPPER FORCING AND PRESENCE OF MID/UPPER LEVEL
RIDGING. HAVE CARRIED A VCTS MENTION AT KSBN FROM 20Z-22Z AND WILL
BE MONITORING TRENDS OVER NEXT HOUR OR SO FOR POSSIBLE TSRA
INCLUSION. SOUTH WINDS AT KSBN MAY BECOME NORTHWEST FOR A TIME IN
THE 20Z-22Z TIMEFRAME DUE TO THE PASSAGE OF THE OUTFLOW
BOUNDARY...OR VARIABLE IN NATURE. A SHEARED UPPER VORT MAX FROM
CENTRAL WISCONSIN INTO EASTERN IOWA WILL TRACK INTO NORTHWEST
INDIANA THIS EVENING WITH SOME POSSIBILITY OF ADDITIONAL ISOLATED
THUNDERSTORMS. OTHER THAN PASSAGE OF THIS WEAK WAVE THIS
EVENING...FORCING WILL BE SOMEWHAT WEAK WITH LOW CONFIDENCE IN
TIMING AND WILL KEEP TAFS DRY THROUGH THE END OF THE PERIOD.
CHANCES OF THUNDER MAY INCREASE LATE TONIGHT INTO TUESDAY MORNING
AS LOW LEVEL FRONT BEGINS TO APPROACH THE AREA...BUT CONFIDENCE
REMAINS LOW IN TIMING/COVERAGE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MARSILI
SYNOPSIS...LOTHAMER
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1259 PM EDT MON AUG 25 2014
.SYNOPSIS...
ISSUED AT 1056 AM EDT MON AUG 25 2014
HOT AND MUGGY CONDITIONS ACROSS THE REGION TODAY INTO TONIGHT.
DEWPOINTS IN THE LOWER 70S WILL CREATE MUGGY CONDITIONS AS HIGH
PRESSURE RETAINS ITS INFLUENCE OVER US. A FRONTAL SYSTEM TO THE
WEST COULD INTRODUCE SOME RAIN TO THE NORTHERN PORTION OF THE
REGION TONIGHT AS IT APPROACHES. HIGH TEMPERATURES TODAY WILL BE IN
THE UPPER 80S TO AROUND 90 WITH THE HEAT INDEX IN THE 90S TO NEAR 100.
LOW TEMPERATURES TONIGHT WILL RANGE FROM THE UPPER 60S NEAR THE
OHIO RIVER TO THE LOWER 70S IN SOUTHERN MICHIGAN.
&&
.UPDATE...
ISSUED AT 1242 PM EDT MON AUG 25 2014
FOCUS FOR THE REMAINDER OF THE AFTERNOON WILL CENTER ON CONVECTIVE
POTENTIAL AND HEAT. RESIDUAL OUTFLOW BOUNDARY FROM UPSTREAM
CONVECTION HAS ALLOWED FOR RENEWED THUNDERSTORM DEVELOPMENT ACROSS
NORTHEAST ILLINOIS. REMNANT OUTFLOW/CONVECTIVE VORT FROM UPSTREAM
CONVECTION WILL HAVE PLENTY OF DOWNSTREAM INSTABILITY TO WORK THIS
AFTERNOON WITH INDICATIONS IN RUC SHORT TERM PROGS OF 3-4K J/KG OF
100 HPA MLCAPES WORKING INTO WESTERN PORTIONS OF THE AREA. DEEP
LAYER SHEAR IS WEAK...BUT GIVEN MAGNITUDE OF INSTABILITY WILL HAVE
TO MONITOR FOR POSSIBILITY OF ISOLATED STRONG/SEVERE STORMS THIS
AFTERNOON. WITH EARLY AFTERNOON UPDATE...WILL GO AHEAD AND MAKE
SOME SOUTHEAST EXPANSION OF SLIGHT CHANCE AND PERHAPS RAISE POPS A
BIT IN THE FAR NORTHWEST DUE TO APPROACH OF OUTFLOW BOUNDARY.
TEMPERATURES/DEW POINTS APPEAR TO BE IN GOOD SHAPE WITH PEAK
AFTERNOON HEAT INDICES STILL LIKELY TO REACH INTO THE UPPER 90S
ACROSS THE WEST. WILL CONTINUE TO GO WTIH CURRENT SPS FOR THIS
AFTERNOON TO HIGHLIGHT HAZARDOUS CONDITIONS ASSOCIATED WITH THE
HEAT/HUMIDITY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 404 AM EDT MON AUG 25 2014
FOCUS OF PERIOD WILL BE TWO FOLD...TEMPERATURES/HEAT INDEX ISSUES AND
CHANCES FOR STORMS.
WARM AND MUGGY CONDITIONS WERE IN PLACE ACROSS THE AREA WITH
TEMPERATURES IN THE 70S AND DEWPOINTS IN THE UPPER 60S NE TO LOWER
70S SW WITH MOST UNSTABLE CAPE VALUES IN THE 500 TO 1500 J/KG RANGE.
WITH NO REAL TRIGGER ACROSS THE AREA NO SHOWERS/STORMS HAVE FORMED
THUS FAR. MAIN FOCUS FOR STORMS HAS BEEN FROM NORTHERN WISCONSIN
INTO PORTIONS OF CENTRAL IOWA WHERE 30 TO 35 KT LOW LEVEL JET WAS
AIDING IN DEVELOPMENT AND MAINTENANCE OF A BROKEN LINE OF STRONG
TO LOCALLY SEVERE STORMS. HI RES MODELS ALL SUGGEST THIS LINE WILL
DROP SLOWLY SOUTHEAST BUT VARY IN HOW MUCH HOLD TOGETHER AS WE
APPROACH 12Z MON AND POINTS BEYOND. WOULD SEEM REASONABLE THAT
SOME SORT OF OUTFLOW BOUNDARY OR REMNANT SHOWERS/STORMS COULD
APPROACH NW AREAS THIS AFTERNOON AND THEN STALL SOMEWHERE TONIGHT
BEING REINFORCED SOMEWHAT BY SFC FRONT THAT WILL BE SINKING SOUTH.
ONLY CHANGE TO GRIDS WILL BE REORIENTATION OF SLGT CHC POPS TO
MORE OF A SW TO NE ORIENTATION. IF SUFFICIENT HEATING TAKES PLACE
AND PROGGED INSTABILITY IS AVAILABLE (SURFACE BASED CAPES IN
EXCESS OF 4000 J/KG IN A WEAKLY SHEAR ENVIRONMENT) THEN SOME
STRONGER STORMS COULD BE A CONCERN.
NOW FOR TEMPERATURES...THE WARM START TO THE MORNING SHOULD ALLOW
TEMPERATURES TO QUICKLY CLIMB INTO THE 80S BY NOON TIME AND POSSIBLY
CLOSE TO 90 IN WESTERN AREAS. DEWPOINTS IN WESTERN AREAS LOOK TO
CLIMB INTO THE MIDDLE 70S IN SOME SPOTS WHICH IF TEMPS DO APPROACH
90 WILL EDGE REAL CLOSE TO HEAT ADVISORY LEVELS (EVEN BRIEFLY TOUCH
IN FAR WEST). WILL HANDLE WITH HWO AND SPS FOR NOW AND LET DAY SHIFT
ASSESS THINGS AFTER SUNRISE AS TO EXTENT OF CLOUD COVER AND POSSIBLE
INFLUENCE FROM UPSTREAM CONVECTION. LOWS TONIGHT WILL DROP BACK INTO
THE UPR 60S TO LOWER 70S.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 404 AM EDT MON AUG 25 2014
LOW OVER SRN MANITOBA THIS MORNING EXPECTED TO LIFT NE INTO QUEBEC
TUESDAY WITH TRAILING CDFNT MOVG INTO OUR CWA. WK FORCING ALONG THE
FRONT COMBINED WITH SOME CAPPING ASSOCIATED WITH UPR RIDGE OVER THE
OH/MID MS VALLEY LIMITS TSTM POTENTIAL TO CHC DESPITE AT LEAST
MODERATE INSTABILITY IN PLACE OVER THE AREA. TEMPS WILL REMAIN ABOVE
NORMAL WITH HIGHS IN THE UPPER 80S AND PM HEAT INDEX READINGS IN THE
90S.
CDFNT EXPECTED TO SAG SOUTH INTO CENTRAL OH/IN TUE NGT. POTENTIAL
FOR TSTMS INCREASES A BIT IN THIS TIMEFRAME AS A SHRTWV CURRENTLY
OVER WRN CANADA MOVES TO THE UPR GRTLKS RESULTING IN MINOR HEIGHT
FALLS AS FAR SOUTH AS OUR CWA. WK CAA SHOULD ALLOW FOR LOWS TO FALL
INTO THE M-U60S ACROSS THE AREA.
RAIN CHANCES DIMINISH WED-WED NGT AS FRONT CONTS TO SAG SOUTH TO THE
OH VALLEY AND SFC HIGH MOVES ESE INTO THE UPR GRTLKS. TEMPS SHOULD
FALL BACK CLOSER TO NORMAL WITH HIGHS IN THE L80S AND LOWS IN THE
L-M60S.
FRONTAL SYSTEM EXPECTED TO LIFT BACK NORTH INTO OUR AREA THU-THU NGT
AS SFC HIGH MOVES TO THE MID ATLANTIC/NORTHEAST U.S.. DVLPG SPLIT
FLOW CUT-OFF LOW OVER THE WRN U.S. BY MID WEEK IS EXPECTED TO MOVE
SLOWLY EAST TO THE CENTRAL PLAINS FRIDAY AND INTO THE MID MS VALLEY
BY SUNDAY WHILE SFC BOUNDARY LINGERS OVER THE AREA... ENHANCING TSTM
POTENTIAL ACROSS OUR AREA OVER THE LABOR DAY WEEKEND... WHILE TEMPS
REMAIN CLOSE TO NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 655 AM EDT MON AUG 25 2014
STRATUS/FOG WITH MVFR/IFR CONDITIONS ATTM SHOULD MIX OUT/BURN OFF
TO VFR BY MID-MORNING. BKN LINE OF TSRA OVER IA/WI MOVG EAST
20KTS. CONVECTIVE ALLOWING MODELS IN DECENT AGREEMENT THAT THIS
CONVECTION WILL GRDLY DIMINISH AS IT MOVES EAST THIS MORNING WHICH
SEEMS REASONABLE AS IT MOVES INTO MORE CAPPED AIRMASS OVER OUR
AREA. COULD BE SCT REMNANT -SHRA/VFR CIGS BRIEF WIND GUSTS AS
REMNANTS MOVE THROUGH SBN TOWARD MIDDAY TOO MUCH UNCERTAINTY
REMAINS TO ADD ANYTHING SGFNT TO TAFS. OUTFLOW BOUNDARY FROM THIS
DYING CONVECTION COULD SET UP OVER NRN INDIANA AND SUPPORT
ISOLATED CONVECTIVE INITIATION AROUND PEAK HEATING BUT CHANCES OF
ANYTHING IMPACTING TERMINALS TOO LOW TO MENTION IN TAFS. APCHG
CDFNT MAY SPREAD SOME SHRA/TSRA INTO NRN INDIANA LATE TONIGHT. FOR
NOW JUST MENTIONED VCSH CLOSEST TO APCHG CDFNT AT SBN... BUT DID
ADD MVFR BR TO BOTH TAFS LATE AS BOUNDARY LAYER REMAINS VERY
MOIST.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...MARSILI
SYNOPSIS...LOTHAMER
SHORT TERM...FISHER
LONG TERM...JT
AVIATION...JT
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
131 PM CDT MON AUG 25 2014
.UPDATE...
ISSUED AT 126 PM CDT MON AUG 25 2014
ISOLATED SEVERE STORMS EXPECTED THIS AFTN PORTIONS OF NORTHEAST AND
EAST CENTRAL IA INTO NORTHWEST IL WITHIN STRONG THERMAL AND
INSTABILITY GRADIENT AHEAD OF WEAK SURFACE LOW MOVING INTO EASTERN
IA. MAIN THREAT WILL BE DAMAGING DOWNBURST WINDS AROUND 60 MPH.
LOCALLY HEAVY RAINFALL ALSO EXPECTED WITH THE STORMS. HAVE UPDATED
THE HWO. IN PROCESS OF SENDING UP A 19Z BALLOON TO BETTER SAMPLE
THE ENVIRONMENT. WILL BE SENDING GRID/ZFP/PFM UPDATE SHORTLY. THIS
WILL ENCORPORATE CONVECTIVE TRENDS AND ALSO LOWERING OF HIGHS
WITH LINGERING COOL POOL OVER PORTIONS OF NORTHEAST IA INTO NORTHWEST
IL.
&&
.SYNOPSIS...
ISSUED AT 334 AM CDT MON AUG 25 2014
THUNDERSTORMS HAVE DEVELOPED EARLY THIS MORNING ALONG AND AHEAD OF
THE SURFACE FRONT EXTENDING ROUGHLY FROM WESTERN LAKE SUPERIOR SW
ACROSS WESTERN WI...SW MN...INTO W CENTRAL IA. THIS WAS ALONG AN
AXIS OF HIGH THETAE INDICATED BY 850 MB DEWPOINTS OF 14 TO 16 C FROM
NORTHEAST KS INTO SW ONTARIO AT 00Z...WITH CONVERGENCE ASSISTED
BY 35KT TO 40 KT SW WINDS AT 850 MB. THIS MOISTURE WAS BEING
PULLED NORTHWARD BY A STRONG SURFACE AND UPPER LEVEL LOW SEEN ON
WV IMAGERY ALONG THE ND/MANITOBA BORDER. AT 3 AM...THE LEADING
LINE OF SCATTERED THUNDERSTORMS WAS MOVING INTO BUCHANAN AND
BENTON COUNTIES...INTO A VERY HUMID AIRMASS WITH DEWPOINTS IN THE
LOWER TO MID 70S AND AIR TEMPERATURES IN THE MID TO UPPER 70S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT MON AUG 25 2014
FORECAST CHALLENGES CENTER ON THUNDERSTORMS THIS MORNING AND AGAIN
TONIGHT...AND HEAT HEADLINES TODAY AS THE HOT AND HUMID CONDITIONS
PERSIST OVER THE REGION. IN THE NEAR TERM...A SEMI-LINEAR MCS WILL
LIKELY MOVE ACROSS THE FORECAST AREA MAINLY NORTH OF I-80...DRIVEN
BY A WEAK SHORTWAVE FLOW IN THE NW FLOW ALOFT. WHILE NO INDIVIDUAL
FORECAST MODEL HAS HAD A GOOD HANDLE ON TRENDS OVERNIGHT...THE
HIGH RES WRF AND RAP MODELS APPEAR TO HAVE THE BEST HANDLE ON THE
CONVECTION ENTERING THE NORTH. THESE HAVE THE THUNDERSTORMS ADVANCING
THROUGH THE NORTH OVER THE NEXT SEVERAL HOURS AND THEN DISSIPATING
BY NOON...AND HAVE TRENDED THE FORECAST ACCORDINGLY. THE LATEST
RAP IS ALONE WITH DEVELOPING THUNDERSTORMS IN THE HIGH MUCAPE
AXIS FURTHER SE...OVER 4000 J/KG...OVER W CENTRAL IL TOWARD
SUNRISE...WHICH WHILE NOT IN THE CURRENT FORECAST CANNOT BE
ENTIRELY RULED AND WILL WATCH TRENDS CLOSELY.
OTHERWISE...THIS SHOULD BE FOLLOWED BY CLEARING SKIES AND A RETURN
TO THE HEAT AND HUMIDITY SEEN OVER THE AREA YESTERDAY. DUE TO
UNCERTAINTIES IN THE TIMING OF THE DISSIPATING MCS IN THE NORTH AND
POSSIBLE DEBRIS CLOUDS FROM STORMS IN THE PLAINS...ALONG WITH 850 MB
TEMPERATURES PROGGED ABOUT 1 DEGREE COOLER...HAVE TRENDED HIGHS A
DEGREE OR TWO COOLER THAN SUNDAY...WITH UPPER 80S NW TO LOWER 90S
CENTRAL AND SOUTH. DEWPOINTS WILL HOLD IN THE LOWER TO MID 70S AND
POSSIBLY TOUCH THE UPPER 70S AT TIMES LATE IN THE DAY. THIS
COMBINATION WILL SEND HEAT INDEX VALUES TO JUST ABOVE 100 ACROSS
THE SOUTH AND WILL KEEP THE PREVIOUS HEAT ADVISORY CONFIGURATION
IN PLACE.
TONIGHT...THE SETUP WILL BE FAVORABLE FOR ANOTHER MCS AS THE SURFACE
FRONT SLOWLY ADVANCES THROUGH THE FORECAST AREA AND MODEST
CONVERGENCE OCCURS IN THE 850 MB THETAE AXIS AS IT SHIFTS OVERHEAD.
HAVE KEPT LIKELY POPS IN THE NORTH WITH SLIGHT TO LOW END CHANCE
POPS IN THE SOUTH TOWARD MORNING. THE MAIN THREAT WILL BE LOCALLY
HEAVY RAINFALL. IT WILL BE ANOTHER WARM AND VERY HUMID NIGHT WITH
TEMPERATURES AND DEWPOINTS IN THE 70S...EXCEPT IN THE FAR NW...WHERE
THE CURRENT FRONTAL TIMING SUGGESTS READINGS LOWERING INTO THE
UPPER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 334 AM CDT MON AUG 25 2014
AN ORGANIZED THUNDERSTORM COMPLEX SHOULD MOVE INTO THE AREA TUESDAY
MORNING AND DISSIPATE DURING THE MORNING. BOUNDARIES LEFT OVER FROM
THIS COMPLEX COMBINED WITH A WEAK FRONT MOVING THROUGH THE AREA WILL
PROVIDE THE FOCUS FOR NEW CONVECTION TUESDAY AFTERNOON AND EVENING.
HIGH MOISTURE LEVELS IN THE LOWER ATMOSPHERE MEANS ANY STORM WILL BE
CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL.
CLOUD COVER AND RAIN WILL PLAY INTO HOW WARM IT WILL GET ON TUESDAY.
THE SOUTHEAST HALF MAY SEE TEMPERATURES AROUND 90 WITH HEAT INDEX
READINGS IN THE UPPER 90S TO JUST OVER 100.
ANOTHER THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP IN WESTERN IOWA
TUESDAY EVENING AND THEN MOVE MAINLY EAST OVERNIGHT INTO WEDNESDAY
MORNING. THIS STORM COMPLEX SHOULD ARRIVE IN THE WESTERN THIRD OF
THE CWFA IN THE PRE-DAWN HOURS AND SLOWLY DISSIPATE ACROSS THE AREA
WEDNESDAY MORNING. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE FROM THE
STORMS DUE TO HIGH MOISTURE LEVELS.
LIKE TUESDAY...BOUNDARIES LEFT OVER FROM THE WEDNESDAY STORM COMPLEX
WILL PROVIDE THE FOCUS FOR NEW CONVECTION WEDNESDAY AFTERNOON AND
EVENING.
SIGNALS FROM THE MODELS SUGGEST YET ANOTHER THUNDERSTORM COMPLEX
WILL DEVELOP IN WESTERN IOWA WEDNESDAY EVENING AND MOVE GENERALLY
EAST OVERNIGHT AND ARRIVE IN THE WESTERN THIRD OF THE AREA IN THE
PRE-DAWN HOURS. LOCALLY HEAVY RAINFALL MAY BE POSSIBLE FROM SOME OF
THE STRONGER STORMS.
THURSDAY ON...
THE MODEL CONSENSUS HAS CHANCE POPS IN EACH 12 HOUR PERIOD FROM
THURSDAY THROUGH SATURDAY NIGHT. TEMPERATURES SHOULD BE NEAR NORMAL.
ON SUNDAY...THE MODEL CONSENSUS HAS SLIGHT CHANCE TO LOW CHANCE POPS.
THE LARGE SCALE PICTURE SUGGESTS THE WEATHER PATTERN WILL REMAIN
FAIRLY ACTIVE WITH A FRONT STALLED OUT JUST SOUTH OF THE AREA. IT
WILL NOT RAIN CONTINUOUSLY THE ENTIRE TIME. THERE WILL BE PERIODS OF
DRY WEATHER THAT MAY LAST 6 OR 12 HOURS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 100 PM CDT MON AUG 25 2014
LINE OF SHOWERS AND STORMS EXTENDS JUST SOUTH AND EAST OF DBQ TO
CID TERMINAL MOVING EAST. ADDITIONAL DEVELOPMENT EXPECTED NEAR
AND NORTH OF I-80 THIS AFTERNOON WITH VARIOUS OUTFLOW BOUNDARIES.
FRONT OVER CENTRAL IA TO PROGRESS EAST AND PASS THROUGH THE
TERMINALS TONIGHT BRINGING SHIFT IN WINDS TO NORTHERLY. ANTICIPATE
SHOWERS AND STORMS TO DEVELOP NORTH OF THE FRONT TONIGHT INTO
TUESDAY MORNING WITH THE GREATEST CHANCES RIGHT NOW LOOKING
NEAR AND NORTH OF I-80. CONDITIONS IN ANY CONVECTION WILL BE
MVFR TO IFR. GUSTY WINDS OF 30+ KTS WILL ALSO BE POSSIBLE WITH
THE STRONGER STORMS THIS AFTERNOON.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR DES MOINES-HENRY
IA-LEE-LOUISA-MUSCATINE-SCOTT-VAN BUREN.
IL...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR BUREAU-HANCOCK-
HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-ROCK ISLAND-
WARREN-WHITESIDE.
MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
UPDATE...05
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...08
AVIATION...05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
108 PM CDT MON AUG 25 2014
.UPDATE...
ISSUED AT 1121 AM CDT MON AUG 25 2014
HAVE UPDATED TO BUMP UP POPS AND EXTEND THROUGH THE AFTERNOON AS
LOOKING LIKELY TO SEE AT LEAST SCATTERED ACTIVITY PERSIST ALL
DAY MOSTLY NORTH OF I-80 WITH MORE ISOLATED OVER SOUTHEAST IA.
THIS ACTIVITY WILL BE AIDED BY WEAK SURFACE LOW NORTHEAST OF
DES MOINES AND INTERACTING WITH OUTFLOW BOUNDARIES...WITH MAIN
BOUNDARY OF NOTE ARCING JUST SOUTH OF I-80. WITH LINGERING
CONVECTION AND DEBRIS CLOUDS HAVE TWEAKED HIGHS DOWN OVER PORTIONS
OF NORTHEAST IA AND FAR NORTHWEST IL INTO THE MID 80S... BUT
WITH DUBUQUE STILL AT 71 DEGS AT 11 AM WOULD NOT BE SURPRISED TO
SEE SOME AREAS STRUGGLE TO HIT 80 OR LOWER 80S FAR NORTH. OTHERWISE
CURRENT HEAT ADVISORY HEADLINE ON TRACK FROM AROUND QUAD CITIES
SOUTH/EAST WITH FEW LOCATIONS ALREADY AT 90 DEGS AND HEAT INDEX
READINGS APPROACHING 100.
LOOKING FURTHER AHEAD TO TONIGHT AND TUESDAY... COLD FRONT THROUGH
NORTHWEST IA MOVING A BIT FASTER THAN MODELS AND LIKELY TO BE
LOCATED SOUTH OF THE CWA TUESDAY MORNING. ANTICIPATE POTENTIAL FOR
MORE ORGANIZED CONVECTION MOVING ACROSS NORTH 1/3-1/2 LATER
TONIGHT INTO TUE AM. IF TRENDS PERSIST THEN GOING FORECAST HIGHS
TOMORROW ARE LIKELY TOO WARM...POSSIBLY BY AS MUCH AS 5-10 DEGS
NOTING THAT AS WE ARE APPROACHING THE NOON HOUR TEMPS ARE IN THE
UPPER 60S TO LOWER 70S IN NORTHWEST IA POST FRONTAL WITH SUNSHINE.
THUS WITH CLOUDS AND RAIN COULD EASILY SEE AREAS STUCK IN THE 70S
ALL DAY TOMORROW. HAVE NOT MADE CHANGES YET AS STILL EVALUATING
MODEL SUITE... AND WILL HAVE MORE ON THIS WITH AFTERNOON DISCO.
UPDATED GRIDS/ZFP/PFM HAVE BEEN ISSUED.
&&
.SYNOPSIS...
ISSUED AT 334 AM CDT MON AUG 25 2014
THUNDERSTORMS HAVE DEVELOPED EARLY THIS MORNING ALONG AND AHEAD OF
THE SURFACE FRONT EXTENDING ROUGHLY FROM WESTERN LAKE SUPERIOR SW
ACROSS WESTERN WI...SW MN...INTO W CENTRAL IA. THIS WAS ALONG AN
AXIS OF HIGH THETAE INDICATED BY 850 MB DEWPOINTS OF 14 TO 16 C FROM
NORTHEAST KS INTO SW ONTARIO AT 00Z...WITH CONVERGENCE ASSISTED
BY 35KT TO 40 KT SW WINDS AT 850 MB. THIS MOISTURE WAS BEING
PULLED NORTHWARD BY A STRONG SURFACE AND UPPER LEVEL LOW SEEN ON
WV IMAGERY ALONG THE ND/MANITOBA BORDER. AT 3 AM...THE LEADING
LINE OF SCATTERED THUNDERSTORMS WAS MOVING INTO BUCHANAN AND
BENTON COUNTIES...INTO A VERY HUMID AIRMASS WITH DEWPOINTS IN THE
LOWER TO MID 70S AND AIR TEMPERATURES IN THE MID TO UPPER 70S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT MON AUG 25 2014
FORECAST CHALLENGES CENTER ON THUNDERSTORMS THIS MORNING AND AGAIN
TONIGHT...AND HEAT HEADLINES TODAY AS THE HOT AND HUMID CONDITIONS
PERSIST OVER THE REGION. IN THE NEAR TERM...A SEMI-LINEAR MCS WILL
LIKELY MOVE ACROSS THE FORECAST AREA MAINLY NORTH OF I-80...DRIVEN
BY A WEAK SHORTWAVE FLOW IN THE NW FLOW ALOFT. WHILE NO INDIVIDUAL
FORECAST MODEL HAS HAD A GOOD HANDLE ON TRENDS OVERNIGHT...THE
HIGH RES WRF AND RAP MODELS APPEAR TO HAVE THE BEST HANDLE ON THE
CONVECTION ENTERING THE NORTH. THESE HAVE THE THUNDERSTORMS ADVANCING
THROUGH THE NORTH OVER THE NEXT SEVERAL HOURS AND THEN DISSIPATING
BY NOON...AND HAVE TRENDED THE FORECAST ACCORDINGLY. THE LATEST
RAP IS ALONE WITH DEVELOPING THUNDERSTORMS IN THE HIGH MUCAPE
AXIS FURTHER SE...OVER 4000 J/KG...OVER W CENTRAL IL TOWARD
SUNRISE...WHICH WHILE NOT IN THE CURRENT FORECAST CANNOT BE
ENTIRELY RULED AND WILL WATCH TRENDS CLOSELY.
OTHERWISE...THIS SHOULD BE FOLLOWED BY CLEARING SKIES AND A RETURN
TO THE HEAT AND HUMIDITY SEEN OVER THE AREA YESTERDAY. DUE TO
UNCERTAINTIES IN THE TIMING OF THE DISSIPATING MCS IN THE NORTH AND
POSSIBLE DEBRIS CLOUDS FROM STORMS IN THE PLAINS...ALONG WITH 850 MB
TEMPERATURES PROGGED ABOUT 1 DEGREE COOLER...HAVE TRENDED HIGHS A
DEGREE OR TWO COOLER THAN SUNDAY...WITH UPPER 80S NW TO LOWER 90S
CENTRAL AND SOUTH. DEWPOINTS WILL HOLD IN THE LOWER TO MID 70S AND
POSSIBLY TOUCH THE UPPER 70S AT TIMES LATE IN THE DAY. THIS
COMBINATION WILL SEND HEAT INDEX VALUES TO JUST ABOVE 100 ACROSS
THE SOUTH AND WILL KEEP THE PREVIOUS HEAT ADVISORY CONFIGURATION
IN PLACE.
TONIGHT...THE SETUP WILL BE FAVORABLE FOR ANOTHER MCS AS THE SURFACE
FRONT SLOWLY ADVANCES THROUGH THE FORECAST AREA AND MODEST
CONVERGENCE OCCURS IN THE 850 MB THETAE AXIS AS IT SHIFTS OVERHEAD.
HAVE KEPT LIKELY POPS IN THE NORTH WITH SLIGHT TO LOW END CHANCE
POPS IN THE SOUTH TOWARD MORNING. THE MAIN THREAT WILL BE LOCALLY
HEAVY RAINFALL. IT WILL BE ANOTHER WARM AND VERY HUMID NIGHT WITH
TEMPERATURES AND DEWPOINTS IN THE 70S...EXCEPT IN THE FAR NW...WHERE
THE CURRENT FRONTAL TIMING SUGGESTS READINGS LOWERING INTO THE
UPPER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 334 AM CDT MON AUG 25 2014
AN ORGANIZED THUNDERSTORM COMPLEX SHOULD MOVE INTO THE AREA TUESDAY
MORNING AND DISSIPATE DURING THE MORNING. BOUNDARIES LEFT OVER FROM
THIS COMPLEX COMBINED WITH A WEAK FRONT MOVING THROUGH THE AREA WILL
PROVIDE THE FOCUS FOR NEW CONVECTION TUESDAY AFTERNOON AND EVENING.
HIGH MOISTURE LEVELS IN THE LOWER ATMOSPHERE MEANS ANY STORM WILL BE
CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL.
CLOUD COVER AND RAIN WILL PLAY INTO HOW WARM IT WILL GET ON TUESDAY.
THE SOUTHEAST HALF MAY SEE TEMPERATURES AROUND 90 WITH HEAT INDEX
READINGS IN THE UPPER 90S TO JUST OVER 100.
ANOTHER THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP IN WESTERN IOWA
TUESDAY EVENING AND THEN MOVE MAINLY EAST OVERNIGHT INTO WEDNESDAY
MORNING. THIS STORM COMPLEX SHOULD ARRIVE IN THE WESTERN THIRD OF
THE CWFA IN THE PRE-DAWN HOURS AND SLOWLY DISSIPATE ACROSS THE AREA
WEDNESDAY MORNING. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE FROM THE
STORMS DUE TO HIGH MOISTURE LEVELS.
LIKE TUESDAY...BOUNDARIES LEFT OVER FROM THE WEDNESDAY STORM COMPLEX
WILL PROVIDE THE FOCUS FOR NEW CONVECTION WEDNESDAY AFTERNOON AND
EVENING.
SIGNALS FROM THE MODELS SUGGEST YET ANOTHER THUNDERSTORM COMPLEX
WILL DEVELOP IN WESTERN IOWA WEDNESDAY EVENING AND MOVE GENERALLY
EAST OVERNIGHT AND ARRIVE IN THE WESTERN THIRD OF THE AREA IN THE
PRE-DAWN HOURS. LOCALLY HEAVY RAINFALL MAY BE POSSIBLE FROM SOME OF
THE STRONGER STORMS.
THURSDAY ON...
THE MODEL CONSENSUS HAS CHANCE POPS IN EACH 12 HOUR PERIOD FROM
THURSDAY THROUGH SATURDAY NIGHT. TEMPERATURES SHOULD BE NEAR NORMAL.
ON SUNDAY...THE MODEL CONSENSUS HAS SLIGHT CHANCE TO LOW CHANCE POPS.
THE LARGE SCALE PICTURE SUGGESTS THE WEATHER PATTERN WILL REMAIN
FAIRLY ACTIVE WITH A FRONT STALLED OUT JUST SOUTH OF THE AREA. IT
WILL NOT RAIN CONTINUOUSLY THE ENTIRE TIME. THERE WILL BE PERIODS OF
DRY WEATHER THAT MAY LAST 6 OR 12 HOURS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 100 PM CDT MON AUG 25 2014
LINE OF SHOWERS AND STORMS EXTENDS JUST SOUTH AND EAST OF DBQ TO
CID TERMINAL MOVING EAST. ADDITIONAL DEVELOPMENT EXPECTED NEAR
AND NORTH OF I-80 THIS AFTERNOON WITH VARIOUS OUTFLOW BOUNDARIES.
FRONT OVER CENTRAL IA TO PROGRESS EAST AND PASS THROUGH THE
TERMINALS TONIGHT BRINGING SHIFT IN WINDS TO NORTHERLY. ANTICIPATE
SHOWERS AND STORMS TO DEVELOP NORTH OF THE FRONT TONIGHT INTO
TUESDAY MORNING WITH THE GREATEST CHANCES RIGHT NOW LOOKING
NEAR AND NORTH OF I-80. CONDITIONS IN ANY CONVECTION WILL BE
MVFR TO IFR. GUSTY WINDS OF 30+ KTS WILL ALSO BE POSSIBLE WITH
THE STRONGER STORMS THIS AFTERNOON.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR DES MOINES-HENRY
IA-LEE-LOUISA-MUSCATINE-SCOTT-VAN BUREN.
IL...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR BUREAU-HANCOCK-
HENDERSON-HENRY IL-MCDONOUGH-MERCER-PUTNAM-ROCK ISLAND-
WARREN-WHITESIDE.
MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
UPDATE...05
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...08
AVIATION...05
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1137 AM CDT MON AUG 25 2014
.UPDATE...
ISSUED AT 1121 AM CDT MON AUG 25 2014
HAVE UPDATED TO BUMP UP POPS AND EXTEND THROUGH THE AFTERNOON AS
LOOKING LIKELY TO SEE AT LEAST SCATTERED ACTIVITY PERSIST ALL
DAY MOSTLY NORTH OF I-80 WITH MORE ISOLATED OVER SOUTHEAST IA.
THIS ACTIVITY WILL BE AIDED BY WEAK SURFACE LOW NORTHEAST OF
DES MOINES AND INTERACTING WITH OUTFLOW BOUNDARIES...WITH MAIN
BOUNDARY OF NOTE ARCING JUST SOUTH OF I-80. WITH LINGERING
CONVECTION AND DEBRIS CLOUDS HAVE TWEAKED HIGHS DOWN OVER PORTIONS
OF NORTHEAST IA AND FAR NORTHWEST IL INTO THE MID 80S... BUT
WITH DUBUQUE STILL AT 71 DEGS AT 11 AM WOULD NOT BE SURPRISED TO
SEE SOME AREAS STRUGGLE TO HIT 80 OR LOWER 80S FAR NORTH. OTHERWISE
CURRENT HEAT ADVISORY HEADLINE ON TRACK FROM AROUND QUAD CITIES
SOUTH/EAST WITH FEW LOCATIONS ALREADY AT 90 DEGS AND HEAT INDEX
READINGS APPROACHING 100.
LOOKING FURTHER AHEAD TO TONIGHT AND TUESDAY... COLD FRONT THROUGH
NORTHWEST IA MOVING A BIT FASTER THAN MODELS AND LIKELY TO BE
LOCATED SOUTH OF THE CWA TUESDAY MORNING. ANTICIPATE POTENTIAL FOR
MORE ORGANIZED CONVECTION MOVING ACROSS NORTH 1/3-1/2 LATER
TONIGHT INTO TUE AM. IF TRENDS PERSIST THEN GOING FORECAST HIGHS
TOMORROW ARE LIKELY TOO WARM...POSSIBLY BY AS MUCH AS 5-10 DEGS
NOTING THAT AS WE ARE APPROACHING THE NOON HOUR TEMPS ARE IN THE
UPPER 60S TO LOWER 70S IN NORTHWEST IA POST FRONTAL WITH SUNSHINE.
THUS WITH CLOUDS AND RAIN COULD EASILY SEE AREAS STUCK IN THE 70S
ALL DAY TOMORROW. HAVE NOT MADE CHANGES YET AS STILL EVALUATING
MODEL SUITE... AND WILL HAVE MORE ON THIS WITH AFTERNOON DISCO.
UPDATED GRIDS/ZFP/PFM HAVE BEEN ISSUED.
&&
.SYNOPSIS...
ISSUED AT 334 AM CDT MON AUG 25 2014
THUNDERSTORMS HAVE DEVELOPED EARLY THIS MORNING ALONG AND AHEAD OF
THE SURFACE FRONT EXTENDING ROUGHLY FROM WESTERN LAKE SUPERIOR SW
ACROSS WESTERN WI...SW MN...INTO W CENTRAL IA. THIS WAS ALONG AN
AXIS OF HIGH THETAE INDICATED BY 850 MB DEWPOINTS OF 14 TO 16 C FROM
NORTHEAST KS INTO SW ONTARIO AT 00Z...WITH CONVERGENCE ASSISTED
BY 35KT TO 40 KT SW WINDS AT 850 MB. THIS MOISTURE WAS BEING
PULLED NORTHWARD BY A STRONG SURFACE AND UPPER LEVEL LOW SEEN ON
WV IMAGERY ALONG THE ND/MANITOBA BORDER. AT 3 AM...THE LEADING
LINE OF SCATTERED THUNDERSTORMS WAS MOVING INTO BUCHANAN AND
BENTON COUNTIES...INTO A VERY HUMID AIRMASS WITH DEWPOINTS IN THE
LOWER TO MID 70S AND AIR TEMPERATURES IN THE MID TO UPPER 70S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT MON AUG 25 2014
FORECAST CHALLENGES CENTER ON THUNDERSTORMS THIS MORNING AND AGAIN
TONIGHT...AND HEAT HEADLINES TODAY AS THE HOT AND HUMID CONDITIONS
PERSIST OVER THE REGION. IN THE NEAR TERM...A SEMI-LINEAR MCS WILL
LIKELY MOVE ACROSS THE FORECAST AREA MAINLY NORTH OF I-80...DRIVEN
BY A WEAK SHORTWAVE FLOW IN THE NW FLOW ALOFT. WHILE NO INDIVIDUAL
FORECAST MODEL HAS HAD A GOOD HANDLE ON TRENDS OVERNIGHT...THE
HIGH RES WRF AND RAP MODELS APPEAR TO HAVE THE BEST HANDLE ON THE
CONVECTION ENTERING THE NORTH. THESE HAVE THE THUNDERSTORMS ADVANCING
THROUGH THE NORTH OVER THE NEXT SEVERAL HOURS AND THEN DISSIPATING
BY NOON...AND HAVE TRENDED THE FORECAST ACCORDINGLY. THE LATEST
RAP IS ALONE WITH DEVELOPING THUNDERSTORMS IN THE HIGH MUCAPE
AXIS FURTHER SE...OVER 4000 J/KG...OVER W CENTRAL IL TOWARD
SUNRISE...WHICH WHILE NOT IN THE CURRENT FORECAST CANNOT BE
ENTIRELY RULED AND WILL WATCH TRENDS CLOSELY.
OTHERWISE...THIS SHOULD BE FOLLOWED BY CLEARING SKIES AND A RETURN
TO THE HEAT AND HUMIDITY SEEN OVER THE AREA YESTERDAY. DUE TO
UNCERTAINTIES IN THE TIMING OF THE DISSIPATING MCS IN THE NORTH AND
POSSIBLE DEBRIS CLOUDS FROM STORMS IN THE PLAINS...ALONG WITH 850 MB
TEMPERATURES PROGGED ABOUT 1 DEGREE COOLER...HAVE TRENDED HIGHS A
DEGREE OR TWO COOLER THAN SUNDAY...WITH UPPER 80S NW TO LOWER 90S
CENTRAL AND SOUTH. DEWPOINTS WILL HOLD IN THE LOWER TO MID 70S AND
POSSIBLY TOUCH THE UPPER 70S AT TIMES LATE IN THE DAY. THIS
COMBINATION WILL SEND HEAT INDEX VALUES TO JUST ABOVE 100 ACROSS
THE SOUTH AND WILL KEEP THE PREVIOUS HEAT ADVISORY CONFIGURATION
IN PLACE.
TONIGHT...THE SETUP WILL BE FAVORABLE FOR ANOTHER MCS AS THE SURFACE
FRONT SLOWLY ADVANCES THROUGH THE FORECAST AREA AND MODEST
CONVERGENCE OCCURS IN THE 850 MB THETAE AXIS AS IT SHIFTS OVERHEAD.
HAVE KEPT LIKELY POPS IN THE NORTH WITH SLIGHT TO LOW END CHANCE
POPS IN THE SOUTH TOWARD MORNING. THE MAIN THREAT WILL BE LOCALLY
HEAVY RAINFALL. IT WILL BE ANOTHER WARM AND VERY HUMID NIGHT WITH
TEMPERATURES AND DEWPOINTS IN THE 70S...EXCEPT IN THE FAR NW...WHERE
THE CURRENT FRONTAL TIMING SUGGESTS READINGS LOWERING INTO THE
UPPER 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 334 AM CDT MON AUG 25 2014
AN ORGANIZED THUNDERSTORM COMPLEX SHOULD MOVE INTO THE AREA TUESDAY
MORNING AND DISSIPATE DURING THE MORNING. BOUNDARIES LEFT OVER FROM
THIS COMPLEX COMBINED WITH A WEAK FRONT MOVING THROUGH THE AREA WILL
PROVIDE THE FOCUS FOR NEW CONVECTION TUESDAY AFTERNOON AND EVENING.
HIGH MOISTURE LEVELS IN THE LOWER ATMOSPHERE MEANS ANY STORM WILL BE
CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL.
CLOUD COVER AND RAIN WILL PLAY INTO HOW WARM IT WILL GET ON TUESDAY.
THE SOUTHEAST HALF MAY SEE TEMPERATURES AROUND 90 WITH HEAT INDEX
READINGS IN THE UPPER 90S TO JUST OVER 100.
ANOTHER THUNDERSTORM COMPLEX IS EXPECTED TO DEVELOP IN WESTERN IOWA
TUESDAY EVENING AND THEN MOVE MAINLY EAST OVERNIGHT INTO WEDNESDAY
MORNING. THIS STORM COMPLEX SHOULD ARRIVE IN THE WESTERN THIRD OF
THE CWFA IN THE PRE-DAWN HOURS AND SLOWLY DISSIPATE ACROSS THE AREA
WEDNESDAY MORNING. LOCALLY HEAVY RAINFALL WILL BE POSSIBLE FROM THE
STORMS DUE TO HIGH MOISTURE LEVELS.
LIKE TUESDAY...BOUNDARIES LEFT OVER FROM THE WEDNESDAY STORM COMPLEX
WILL PROVIDE THE FOCUS FOR NEW CONVECTION WEDNESDAY AFTERNOON AND
EVENING.
SIGNALS FROM THE MODELS SUGGEST YET ANOTHER THUNDERSTORM COMPLEX
WILL DEVELOP IN WESTERN IOWA WEDNESDAY EVENING AND MOVE GENERALLY
EAST OVERNIGHT AND ARRIVE IN THE WESTERN THIRD OF THE AREA IN THE
PRE-DAWN HOURS. LOCALLY HEAVY RAINFALL MAY BE POSSIBLE FROM SOME OF
THE STRONGER STORMS.
THURSDAY ON...
THE MODEL CONSENSUS HAS CHANCE POPS IN EACH 12 HOUR PERIOD FROM
THURSDAY THROUGH SATURDAY NIGHT. TEMPERATURES SHOULD BE NEAR NORMAL.
ON SUNDAY...THE MODEL CONSENSUS HAS SLIGHT CHANCE TO LOW CHANCE POPS.
THE LARGE SCALE PICTURE SUGGESTS THE WEATHER PATTERN WILL REMAIN
FAIRLY ACTIVE WITH A FRONT STALLED OUT JUST SOUTH OF THE AREA. IT
WILL NOT RAIN CONTINUOUSLY THE ENTIRE TIME. THERE WILL BE PERIODS OF
DRY WEATHER THAT MAY LAST 6 OR 12 HOURS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 645 AM CDT MON AUG 25 2014
A SLOW MOVING AXIS OF THUNDERSTORMS OVER NORTHEAST IOWA MAY
BRIEFLY IMPACT THE CID AND DBQ TERMINALS EARLY THIS MORNING. FOG
AND A FEW AREAS OF LOW CLOUDS WILL IMPACT MOST OF THE TERMINALS
WITH PERIODS OF MVFR CONDITIONS UNTIL MID MORNING.
OTHERWISE...TODAY WILL BE MAINLY VFR WITH VERY HUMID CONDITIONS.
ANOTHER ROUND OF THUNDERSTORMS IS EXPECTED TO MOVE THROUGH EASTERN
IOWA AND NORTHWEST ILLINOIS LATE TONIGHT AS A COOL FRONT SLOWLY
DROPS SOUTH THROUGH THE AREA. THIS IS MOST LIKELY TO AFFECT THE
CID...DBQ AND MLI TERMINALS...WHERE PROB30 GROUPS COVER THE
POTENTIAL FOR NOW. ALSO...LIGHT WINDS AND LINGERING LOW LEVEL
MOISTURE WILL ALSO LEAD TO MVFR FOG...WHICH IS ALSO INCLUDED FOR
THE LATE NIGHT AND EARLY MORNING PERIODS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR LOUISA-MUSCATINE-
SCOTT.
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR DES MOINES-HENRY
IA-LEE-VAN BUREN.
IL...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR BUREAU-HENRY IL-
MERCER-PUTNAM-ROCK ISLAND-WHITESIDE.
HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR HANCOCK-HENDERSON-
MCDONOUGH-WARREN.
MO...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR CLARK-SCOTLAND.
&&
$$
UPDATE...05
SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...08
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
144 PM EDT MON AUG 25 2014
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EDT MON AUG 25 2014
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A VIGOROUS LOOKING
SHORTWAVE LIFTING THRU ND INTO MANITOBA. ASSOCIATED SFC LOW WAS
MOVING INTO SE MANITOBA WITH COLD FRONT EXTENDING THRU FAR ERN MN.
AS EXPECTED...SCT TSTMS DEVELOPED AHEAD OF FRONT IN MN LATE
YESTERDAY AFTN/EVENING. STORMS THEN ORGANIZED INTO A LINE AND PUSHED
E INTO WI/UPPER MI. AS OF 09Z...SHRA/TSTMS EXTENDED FROM NCNTRL LAKE
SUPERIOR TO THE HURON MTNS AND CRYSTAL FALLS. CONVECTION HAS HELD
TOGETHER FOR MUCH OF THE NIGHT...AND IT HAS ONLY BEEN IN THE LAST HR
OR TWO THAT A NOTABLE DIMINISHING TREND HAS BEGUN. NSSL WRF RUN FROM
00Z/24 AUG DID A GREAT JOB AND BETTER THAN ANY OTHER MODEL IN
CAPTURING WHAT OCCURRED LAST NIGHT INTO EARLY THIS MORNING...
INCLUDING THE DIMINISHING TREND NOW UNDERWAY.
WHILE THERE IS STILL SOME INCREASE IN INSTABILITY AHEAD OF
CONVECTION PER SPC MESOANALYSIS OF 3HR ML/MUCAPE CHANGE...OVERALL
MAGNITUDE OF INSTABILITY IS NOTABLY LESS THAN WHAT WAS SUPPORTING
THE CONVECTION EARLIER IN THE NIGHT. DIMINISHING INSTABILITY
COMBINED WITH WEAKENING LOW-LEVEL JET WILL CONTINUE TO CAUSE
SHRA/TSRA TO WEAKEN AS THEY PUSH E THIS MORNING. QUESTION THEN
BECOMES WHETHER THERE WILL BE REDEVELOPMENT ALONG THE MOISTURE AXIS
THAT WILL BE SLOWING DOWN. NSSL WRF INCLUDING THE NCEP ARW/NMM WHICH
ALSO DID WELL WITH CONVECTION LAST NIGHT SUGGEST LITTLE OR NO
ADDITIONAL DEVELOPMENT THIS AFTN. WILL BASICALLY FOLLOW THAT
SCENARIO GIVEN A LACK OF MUCH FORCING THIS AFTN. WITH INCREASING
SUNSHINE AND 850MB THERMAL RIDGE OVER THE AREA...TODAY SHOULD BE THE
WARMEST DAY OF THE WEEK. FCST SOUNDINGS SUPPORT MAX TEMPS AS HIGH AS
THE MID/UPPER 80S OVER ROUGHLY THE W HALF. COULD BE WARMER DEPENDING
ON HOW QUICKLY CLOUDS SCATTER OUT. E WILL BE COOLER WITH MORE CLOUD
COVER AND CONTINUED SOUTHERLY FLOW OFF LAKE MICHIGAN.
LOOKS LIKE A SECONDARY COLD FRONT/TROF WILL SWEEP ACROSS THE AREA
LATER THIS AFTN/EVENING. AS THE TROF MOVES INTO THE ERN FCST AREA
THIS EVENING WHERE MOISTURE/INSTABILITY LINGER...ISOLD SHRA AND
PERHAPS A TSRA MAY DEVELOP FROM ERN LAKE SUPERIOR INTO ERN UPPER MI.
OTHERWISE...EXPECT A DRY NIGHT...BECOMING COOLER AND LESS HUMID.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 403 AM EDT MON AUG 25 2014
A FAIRLY QUIET AND GENERALLY DRY LONG TERM PERIOD IS IN STORE FOR
THE UPPER GREAT LAKES REGION FOR TUESDAY THROUGH THE WEEKEND. THIS
TRANSITION WILL OCCUR AS A RESULT OF THE LOW PRESSURE SYSTEM MOVING
THROUGH NORTHERN ONTARIO TODAY AND THE ASSOCIATED COLD FRONT THAT
PASSES THROUGH. BEHIND THIS LOW AND ASSOCIATED SHORTWAVE...HIGH
PRESSURE FROM THE EASTERN DAKOTAS WILL SHIFT EAST OVER THE UPPER
GREAT LAKES REGION BY WEDNESDAY WHILE A WEAK UPPER TROUGH SWEEPS
THROUGH. IN GENERAL...EXPECT THIS HIGH PRESSURE RIDGE TO SUPPRESS
ANY PRECIPITATION TO THE SOUTH OF THE AREA THROUGH THURSDAY. THERE
ARE A COUPLE MINOR ITEMS TO NOTE. FIRST...THE SECONDARY SHORTWAVE
MOVING THROUGH THE FLOW LATE TUESDAY NIGHT INTO WEDNESDAY MORNING
COULD TRY TO SPARK AN ISOLATED SHOWER BUT FEEL THE DRY AIR IN THE
LOWER LEVELS ASSOCIATED WITH THE HIGH PRESSURE RIDGE WILL INHIBIT
ANY RAIN FROM REACHING THE SURFACE. THUS...WILL JUST SHOW PASSING
MID CLOUDS AS THAT WAVE MOVES THROUGH. THE OTHER ITEM IS THE MUCH
COOLER AIR BELOW 850MB THAT WILL BE SURGING INTO THE CWA LATE
TONIGHT INTO TUESDAY. THIS WILL SETUP A RETURN TO ANOTHER COOLER
PERIOD OF HIGH TEMPERATURES OVER THE CWA. WITH THE COLD AIR JUST
STARTING TO MOVE IN ON TUESDAY...HIGHS OVER THE CENTRAL/EAST WILL
STILL RISE INTO THE UPPER 60S AND LOWER 70S WHILE AREAS OVER THE
WEST NEAR LAKE SUPERIOR WILL STAY IN THE MID 60S WITH THE
GUSTY WESTERLY WIND OFF THE LAKE. WEDNESDAY WILL BE THE COOLEST DAY
(AIDED BY THE MORNING MID CLOUDS LIMITING HEATING AND MODEL AVERAGE
850MB TEMPS AROUND 6-7C)...WITH HIGHS IN THE 60S OVER MOST OF THE
CWA. 850MB TEMPS WILL REBOUND SLIGHTLY ON THURSDAY AND ALLOW HIGHS
TO BE IN THE UPPER 60S TO AROUND 70 DEGREES. ALONG WITH THAT COOLER
AIR ON TUESDAY MORNING...SOME OF THE MODELS ARE INDICATING ENOUGH
MOISTURE FOR SOME CLOUDS OVER THE NORTH HALF OF THE CWA. THINK THE
COVERAGE WILL BE THE GREATEST DURING THE AFTERNOON HOURS WHEN THE
DIURNAL HEATING IS MAXIMIZED AND WILL SHOW PARTLY CLOUDY SKIES
DURING THAT TIME. EXPECT MOSTLY CLEAR SKIES FOR THE REST OF THE
MIDDLE OF THE WORK WEEK.
THE FOCUS THURSDAY NIGHT INTO THE WEEKEND WILL BE THE UPPER
DISTURBANCE MOVING OUT OF THE CENTRAL ROCKIES AND INTO THE CENTRAL
PLAINS ON WEDNESDAY. THE INITIAL PORTION OF THIS WAVE WILL SHIFT
NORTHEAST TOWARDS THE UPPER GREAT LAKES REGION THURSDAY NIGHT AND
FRIDAY...WITH MODELS STILL VARYING ON THE NORTHWARD EXTENT OF THE
WAVE AND ASSOCIATED PRECIP. CURRENT CONSENSUS IS FOR IT TO BRUSH
THE SOUTHEAST THIRD OF THE CWA AND WILL SHOW SLIGHT CHANCES IN THAT
AREA. THE SECOND WAVE WILL PUSH THROUGH THE AREA FRIDAY NIGHT INTO
SATURDAY AND BRING ANOTHER OPPORTUNITY FOR PRECIPITATION. MODELS
ALSO VARYING ON THE LOCATION THIS WAVE...SO WILL FOLLOW A BLEND OF
GEM/GFS/ECMWF FOR POPS (SLIGHT OR LOW END CHANCES) WITH THE BEST
CHANCES OVER THE SOUTHEAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 139 PM EDT MON AUG 25 2014
VFR CONDITIONS WILL BE THE RULE THROUGH THE FCST PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EDT MON AUG 25 2014
FOG MAY BE AN ISSUE OVER PORTIONS OF LAKE SUPERIOR THRU THIS
EVENING...MAINLY CNTRL/E AND ESPECIALLY NE GIVEN THE HUMID AIR MASS
AND PCPN THAT HAS OCCURRED. PASSAGE OF COLD FRONT AND ARRIVAL OF
DRIER AIR TODAY/THIS EVENING WILL THEN WORK TO CLEAR OUT THE FOG
FROM W TO E. BEHIND FRONT...WESTERLY WINDS WILL INCREASE TO
15-25KT OVER WRN LAKE SUPERIOR THIS AFTN AND THEN OVER CNTRL LAKE
SUPERIOR THIS EVENING. THESE STRONGER WINDS WILL LINGER INTO TUE
MORNING...THEN WINDS WILL DIMINISH AS HIGH PRES MOVES CLOSER TO THE
AREA. THE HIGH WILL SETTLE INTO THE UPPER LAKES TUE NIGHT THRU
THU...BRINGING A PERIOD OF LIGHTER WINDS MOSTLY UNDER 15KT. THE
LIGHTER WINDS WILL LINGER INTO FRI DESPITE THE HIGH MOVING TO THE E.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...TITUS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
329 PM EDT MON AUG 25 2014
.SYNOPSIS...
A WARM RIDGE OF HIGH PRESSURE WILL EXPAND EASTWARD ACROSS THE AREA
THROUGH LATE WEEK. TROPICAL CYCLONE CRISTOBAL WILL MOVE NORTH AND
NORTHEAST...PASSING SEVERAL HUNDRED MILES EAST OF THE CAROLINA COAST
TUESDAY NIGHT AND WEDNESDAY. A WARMING TREND WILL DEVELOP MID AND
LATE WEEK...WITH MORE TYPICAL LATE SUMMER WEATHER EXPECTED INTO THE
WEEKEND. THE RISK FOR SHOWERS AND THUNDERSTORMS WILL BE ON THE
INCREASE EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...COOL CANADIAN HIGH PRESSURE CENTERED OVER NEW
ENGLAND CONTINUES TO RIDGE DOWN THE COAST...CREATING FALL-LIKE
WEATHER ACROSS THE EASTERN CAROLINAS. TEMPS THIS AFTN HAVE STRUGGLED
ONLY INTO THE LOW 80S THANKS TO COOL NE FLOW AND WIDESPREAD CLOUD
COVER EAST OF I-95. THIS CLOUD COVER IS INCREASING THANKS TO MOIST
ADVECTION ON NE FLOW...AND SHOWERS HAVE OVERSPREAD THE COASTAL
PORTIONS OF THE CAPE FEAR REGION...AS EXPECTED...AND DEPICTED ON
HIGH RES HRRR THROUGH THIS AFTN. THESE SHOWERS DO NOT FEATURE
CONSIDERABLE DEPTH...AS COLUMN MOISTENING EXISTS ONLY TO ABOUT 10
KFT /700MB/...ABOVE WHICH VERY DRY AIR EXISTS EMBEDDED WITHIN A
SUBSIDENCE INVERSION THANKS TO STRENGTHENING MID-LEVEL RIDGE.
THEREFORE...DO NOT EXPECT ANY LIGHTNING THIS AFTN OR EVE...EVEN AS
SHOWERS BECOME SLIGHTLY MORE WIDESPREAD ALONG THE EASTERN THIRD OF
THE CWA INTO TONIGHT.
DRYING WILL OCCUR IN THE LOWER PORTIONS OF THE COLUMN AFTER
DARK...AND ANY SHOWER ACTIVITY WILL WANE BY MIDNIGHT. NE WINDS WILL
CONTINUE AT 10-15 MPH EVEN AFTER DARK...CONTINUING THE CAA...AND
ALLOWING TEMPS TO FALL TO 62-67...COOLEST NORTH...IN A DRY AND CLEAR
COLUMN.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...NE FLOW WILL BEGIN TO ABATE LATER TUE AND
TUE NIGHT AS SURFACE HIGH PRESSURE DEVELOPS SOUTHWARD AND IN
CLOSER PROXIMITY TO THE EASTERN CAROLINAS. TROPICAL CYCLONE
CRISTOBAL WILL BE MOVING TO THE NE...HUGGING 70 DEG WEST LONGITUDE
AS IT MOVES NORTH OF OUR LATITUDE TUE NIGHT AND WED. NO DIRECT
IMPACTS FROM THE CYCLONE ARE EXPECTED. EXPANSIVE RIDGE ALOFT TO
OUR WEST WILL EXPAND EASTWARD AND ACROSS THE AREA WED AND WED
NIGHT AND THIS WILL BRING RISING HEIGHTS...INCREASING SUBSIDENCE AND
TEMPS MORE TYPICAL OF LATE SUMMER ACROSS THE EASTERN CAROLINAS.
WILL NOT INCLUDE ANY POPS THROUGH THE PERIOD. IT IS NOT IMPOSSIBLE
THAT A FEW SHOWERS OFFSHORE MANAGE TO BRUSH THE COAST ON TUE...BUT
THE RISK IS VERY SMALL. WILL CALL FOR AN ABUNDANCE OF SUNSHINE
THROUGH THE PERIOD EXCEPT FOR SOME STRATOCUMULUS WHICH MAY BRUSH
THE COAST TUE AND TUE NIGHT.
HIGHS WILL BE MAINLY IN THE LOWER TO MID 80S TUE AND IN THE UPPER
80S TO AROUND 90 ON WED. ALONG THE COAST...THE SEABREEZE SHOULD
HOLD TEMPS TO THE MID 80S WED AFTERNOON. LOWS WILL BE IN THE LOWER
TO MID 60S TUE NIGHT AND MAINLY UPPER 60S TO LOWER 70S WED NIGHT.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...THE FOCUS ON THE EXTENDED FORECAST NOW SHIFTS
TO THE END OF THE PERIOD WHEN A MORE ACTIVE PATTERN SHOULD
DEVELOP. MID LEVEL RIDGING WILL DOMINATE CONDITIONS THURSDAY
THROUGH SATURDAY . A BROAD MID LEVEL TROUGH WILL BREAK DOWN THE
RIDGE SLOWLY SUNDAY AND MONDAY WITH A MORE MOISTURE LADEN
SOUTHWEST FLOW DEVELOPING. AT THE SURFACE...HIGH PRESSURE WILL
PREVAIL AS WELL. THERE IS A BACKDOOR FRONT STILL IN THE PICTURE
FOR LATE THURSDAY AND FRIDAY BUT THIS SHOULD HAVE LITTLE IMPACT ON
THE ACTUAL FORECAST OTHER THAN TO BUMP THE TEMPERATURES BACK A
COUPLE OF DEGREES. REGARDING POPS...VALUES INCREASE FROM SLIGHT
CHANCE SATURDAY TO LOWER CHANCE BY MONDAY. THIS PRIMARILY OF
PRECIPITABLE WATER VALUES INCREASING FROM JUST UNDER AN INCH
FRIDAY TO WELL ABOVE TWO INCHES MONDAY. TEMPERATURES HOVER AROUND
CLIMATOLOGY LEANING TOWARD A DEGREE OR TWO ABOVE FOR THE MOST
PART.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...THE STRATOCU HAS BLOSSOMED OVER THE PAST COUPLE OF
HOURS. LOOK FOR AN MVFR STRATOCU CEILING THROUGH MOST OF THE
AFTERNOON...WITH PERIODS OF VFR AS THE CU SCATTERS. GUSTY
NORTHEAST WINDS WILL BE THE RULE...WITH A FEW BURSTS NEAR 25 KTS
ALONG THE IMMEDIATE COAST. THE TROPICAL SYSTEM OFFSHORE WILL NOT
BE A FACTOR TODAY...ALTHOUGH IT MAY ENHANCE THE GRADIENT SLIGHTLY.
DIMINISHING WINDS THIS EVENING WITH CLEARING SKIES. SOME LIGHT FOG
IS POSSIBLE AT THE INLAND TERMINALS...BUT WINDS ALONG THE COAST
SHOULD BE HIGH ENOUGH TO PRECLUDE FOG. TUESDAY...CONTINUED
NORTHEAST FLOW...NOT AS STRONG AS TODAY HOWEVER.
EXTENDED OUTLOOK...EXPECT VFR CONDITIONS THROUGH THE EXTENDED
PERIOD. SLIGHT CHANCE OF SHOWERS FOR OUR NORTHERN TERMINALS FRI.
INCREASING CHANCES FOR PRECIP SATURDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM MONDAY...HIGH PRESSURE CONTINUES TO RIDGE DOWN FROM NEW
ENGLAND JUST INLAND FROM THE WATERS...WHICH WHEN COMBINED WITH THE
PRESENCE OF TROPICAL STORM CRISTOBAL NEAR THE BAHAMAS PRODUCES A
PINCHED GRADIENT WITH GUSTY NE WINDS. THESE WINDS HAVE BEEN
SUSTAINED AT 15-20 KTS...WITH GUSTS ABOVE 25 KTS NEAR THE 20 NM
BOUNDARY AND OVER THE NORTHERN COASTAL WATERS. THIS IS EXPECTED TO
CONTINUE WITH LITTLE FLUCTUATION THROUGH THE PERIOD. SE SWELL FROM
CRISTOBAL HAS AMPLIFIED AND REACHED THE WATERS...AND IS SHOWING UP
AS 2-3FT/10SEC AT THE BUOYS. THIS SWELL...ALONG WITH A 5-7 FT NE
WIND WAVE...ARE TOGETHER IN THE WAVE SPECTRUM PRODUCING SIGNIFICANT
SEAS OF 4-7 FT THIS AFTN...WHICH WILL PERSIST INTO TUESDAY MORNING.
THE ONGOING SMALL CRAFT ADVISORY REMAINS UNCHANGED FOR THIS PERIOD
TO ACCOUNT FOR THE HAZARDOUS MARINE CONDITIONS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...THE PRESSURE DIFFERENCE BETWEEN HIGH
PRESSURE TO THE NORTH AND A TROPICAL CYCLONE WELL OFF THE
SOUTHEAST COAST WILL KEEP A RATHER TIGHT PRESSURE GRADIENT ACROSS
THE WATERS INTO TUE NIGHT. THE GRADIENT WILL RELAX SIGNIFICANTLY
WED AND WED NIGHT AS HIGH PRESSURE DOMINATES. WIND SPEEDS WILL BE
UP TO 20 KT TUE... BECOMING 10 KT OR LESS BY WED AFTERNOON. THE
DIRECTION WILL BE NE TUE...BUT WILL SLOWLY BACK TO NNE OR N TUE
NIGHT. THE DIRECTION WILL BECOME MORE SOUTHERLY DURING WED AS THE
SEABREEZE CIRCULATION DOMINATES. SEAS WILL BE UP TO 4 TO 6 FT
TUE...SUBSIDING TO 2 TO 4 FT BY WED AFTERNOON. A 10 TO 12 SECOND
SE SWELL IS EXPECTED THROUGH THE PERIOD.
LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...VERY LIGHT WIND FIELDS THROUGH THE PERIOD
AS HIGH PRESSURE WILL PREVAIL AT ALL LEVELS OF THE ATMOSPHERE.
DIRECTIONS WILL GENERALLY BE FROM THE SOUTH WITH THE SEA BREEZE
BACKING THE DIRECTION EACH AFTERNOON CLOSER TO THE COAST. ALL
SPEEDS ARE WITHIN A COUPLE OF KNOTS EITHER SIDE OF TEN KNOTS.
BENIGN SEAS WILL PREVAIL THROUGH THE PERIOD WITH 1-3 FEET.
&&
.TIDES/COASTAL FLOODING...
AS OF 300 PM MONDAY...RIDGE OF HIGH PRESSURE CENTERED OVER NEW
ENGLAND CONTINUES TO RIDGE DOWN THE COAST...WITH THE AXIS JUST
INLAND FROM THE SHORE. THIS LEAVES THE WATERS SANDWICHED BETWEEN THE
HIGH...AND TROPICAL STORM CRISTOBAL NEAR THE BAHAMAS...PRODUCING
PERSISTENT AND STRONG NE WINDS LOCALLY. THESE NE WINDS ARE PUSHING
WATER TOWARDS SHORE...AND LOCAL TIDAL ANOMALIES ARE RUNNING +1 TO +2
FT TODAY. THESE ANOMALIES WILL RISE ON TOP OF A NEW-MOON ENHANCED
ASTRONOMICAL HIGH TIDE THIS EVENING...TO PRODUCE MINOR COASTAL
FLOODING ALONG ALL EAST FACING BEACHES. HIGH TIDE IS AROUND 8PM THIS
EVENING...AND MINOR COASTAL FLOOD THRESHOLDS MAY BE EXCEEDED FOR
ABOUT A 1 HR WINDOW BOTH SIDES OF HIGH TIDE. A COASTAL FLOOD
ADVISORY HAS AGAIN BEEN ISSUED FOR THE EAST FACING BEACHES OF THE
CAPE FEAR REGION...AS WELL AS THE ENTIRE GRAND STRAND OF SOUTH
CAROLINA.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...COASTAL FLOOD ADVISORY FROM 7 PM TO 10 PM EDT THIS EVENING FOR
SCZ054-056.
NC...COASTAL FLOOD ADVISORY FROM 7 PM TO 10 PM EDT THIS EVENING FOR
NCZ106-108.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT TUESDAY FOR
AMZ250-252-254- 256.
&&
$$
NEAR TERM...JDW
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...JDW/DL
TIDES/COASTAL FLOODING...JDW
AREA FORECAST DISCUSSION
NWS BISMARCK ND
325 PM CDT MON AUG 25 2014
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 323 PM CDT MON AUG 25 2014
THE MAIN FORECAST ISSUES IN THE LONG TERM PERIOD WILL BE
TEMPERATURES TONIGHT AND PRECIPITATION CHANCES SOUTHWEST AND SOUTH
CENTRAL LATE TONIGHT AND TUESDAY. THE PESKY UPPER LOW IS NOW
LIFTING OUT OF THE AREA. ONE LAST TRAILING VORT COMBINED WITH
ANOTHER APPROACHING SHORTWAVE IS KEEPING A FEW SHOWERS OVER
NORTHEAST MONTANA AND NORTHWEST NORTH DAKOTA. THE 18Z HRRR SHOWS
THE SHOWERS HANGING ON THROUGH 00Z. WILL MENTION SOME SCATTED
SPRINKLES NORTHWEST LATE THIS AFTERNOON.
THE APPROACHING SHORTWAVE...IN COMBINATION WITH AN STRENGTHENING
UPPER LEVEL JET WILL PRODUCE INCREASING CLOUDS AND EVENTUALLY A
SWATH OF LIGHT PRECIPITATION...MOVING INTO THE SOUTHWEST LATE
TONIGHT AND SPREADING ACROSS THE SOUTHWEST AND SOUTH CENTRAL ON
TUESDAY. THE INCREASING CLOUDS SHOULD HELP TEMPER THE MERCURY DROP
LATE TONIGHT OVER THE SOUTHWEST. BUT WITH DECREASING CLOUDS...AND
DIMINISHING WINDS...MOST AREAS ARE EXPECTED TO FALL INTO THE
LOWER TO MIDDLE 40S. WOULD NOT BE SURPRISED TO SEE A FEW LOWS
INTO THE UPPER 30S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 323 PM CDT MON AUG 25 2014
A BROAD POSITIVELY TILTED TROUGH IS FORECAST TO HAVE MOVED EAST OF
THE FORECAST AREA BY TUESDAY NIGHT...WITH DRY CONDITIONS EXPECTED
TUESDAY NIGHT.
A WARMING TREND ALONG WITH DRY CONDITIONS ARE EXPECTED TO CONTINUE
WEDNESDAY THROUGH FRIDAY AS WEAK UPPER LEVEL RIDGING BUILDS OVER
THE NORTHERN PLAINS. NEAR NORMAL HIGHS ARE FORECAST BY FRIDAY.
THE UPPER RIDGE IS PROGGED TO BREAK DOWN SOMEWHAT BY FRIDAY
NIGHT...AND WEAK WAVES IN THE UPPER FLOW ALOFT WILL GENERATE CHANCES
FOR THUNDERSTORMS EACH PERIOD FRIDAY NIGHT THROUGH MONDAY. NEAR
NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH THE WEEKEND AND
INTO MONDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 323 PM CDT MON AUG 25 2014
MVFR TO LOW VFR CEILINGS ARE EXPECTED TO ALL LIFT TO LOW VFR
AROUND 22 UTC. NORTHWEST SURFACE FLOW WILL DIMINISH FROM WEST TO
EAST AFTER 21 UTC. VFR CONDITIONS ARE EXPECTED ACROSS TAF SITES
TONIGHT AND TUESDAY MORNING.
&&
.HYDROLOGY...
ISSUED AT 323 PM CDT MON AUG 25 2014
HEAVY RAINFALL IN THE PAST COUPLE OF DAYS HAVE CAUSED OVERLAND
FLOODING...AS WELL AS RISES IN CREEKS...RIVERS...AND STREAMS IN
PARTS OF SOUTH CENTRAL NORTH DAKOTA - ESPECIALLY WEST OF THE
MISSOURI RIVER. SIOUX...GRANT...AND WESTERN MORTON COUNTIES SAW
LARGE AREAS OF 2 TO 4 INCHES OF RAIN.
AN AREAL FLOOD WARNING REMAINS IN EFFECT FOR PARTS OF WESTERN MORTON
COUNTY AND PARTS OF NORTHERN GRANT COUNTY. THESE AREAS INCLUDE THE
BIG MUDDY CREEK BETWEEN GLEN ULLIN AND ALMONT...SOUTHWARD TO
HEIL...CARSON...AND LARK. THESE AREAS CONTAIN SMALL CREEKS AND
STREAMS THAT ARE TRIBUTARIES TO THE HEART RIVER.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TWH
LONG TERM...JV
AVIATION...TWH
HYDROLOGY...TWH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
410 PM EDT MON AUG 25 2014
.SYNOPSIS...
TEMPERATURES WILL CONTINUE TO WARM ACROSS THE REGION WITH A STRONG
UPPER LEVEL RIDGE ALOFT. HIGH PRESSURE AT THE SURFACE WILL REMAIN
ALONG THE EAST COAST ON TUESDAY WHILE LOW PRESSURE OVER ONTARIO
PASSES NORTH OF THE GREAT LAKES. THE ASSOCIATED COLD FRONT WILL PUSH
SOUTH ACROSS THE AREA LATE TUESDAY NIGHT INTO WEDNESDAY...FOLLOWED
BY HIGH PRESSURE BUILDING EAST ACROSS THE GREAT LAKES ON THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
THE FORECAST AREA REMAINS BENEATH A STRONG UPPER LEVEL RIDGE ALOFT
WITH SURFACE HIGH PRESSURE TO THE EAST AND A TROUGH MOVING INTO THE
WESTERN GREAT LAKES. THERE IS ABOUT A 10 DEGREE SPREAD IN BOTH
TEMPERATURES AND DEWPOINTS ACROSS THE AREA LATE THIS AFTERNOON AS A
VERY WARM AND HUMID AIRMASS SPREADS INTO NW OHIO WHILE SEASONABLE
CONDITIONS REMAIN IN WESTERN PENNSYLVANIA.
MAIN FORECAST CONCERN FOR TONIGHT REVOLVES AROUND THE EVOLUTION OF
THE MCS MOVING INTO NW INDIANA. A VERY UNSTABLE ENVIRONMENT IS IN
PLACE ACROSS NRN ILLINOIS AND WESTERN INDIANA...WITH INSTABILITY
DECREASING INTO WESTERN OHIO WHERE ML CAPES ARE CLOSER TO 1000-1500
J/KG. STORM MOTION HAS BEEN TOWARDS THE SOUTH SOUTHEAST TOWARDS THE
BETTER INSTABILITY OVER THE LAST HOUR OR TWO WITH GENERALLY WEAK
FLOW ALOFT. 850-300MB FLOW IS WESTERLY IN WESTERN INDIANA THEN
BECOMES MORE NORTHWESTERLY TO THE EAST. THE LATEST RUN OF THE HRRR ALSO
SHOWS THIS ACTIVITY TRACKING TO THE SOUTHEAST AND HAVE ADDED A
CHANCE OF THUNDERSTORMS FOR THIS EVENING INTO NW OHIO. OUT OF AHEAD
OF THIS COMPLEX WE ARE ALSO SEEING SOME SMALL SHOWERS POPPING UP IN
EXTREME NW OHIO BUT THESE WILL LIKELY STRUGGLE WITH THE CAP STILL IN
PLACE. THE SEVERE WEATHER THREAT REMAINS SOMEWHAT UNCLEAR AT THIS
TIME. ONLY ONE WARNING HAS BEEN ISSUED IN NRN INDIANA AND THERE HAVE
BEEN NO REPORTS OF SEVERE WEATHER AS OF 345 PM EDT. SHEAR SHOULD BE
A LIMITING FACTOR AND THE LATEST RADAR IMAGERY SUGGESTS THE GUST
FRONT MAY BE OUTPACING THE DEEPER CONVECTION. THIS WOULD LIMIT THE
SEVERE POTENTIAL AS WE HEAD INTO THIS EVENING.
OTHERWISE THERE IS ALSO A CHANCE OF SHOWERS AND THUNDERSTORMS
SINKING SOUTH ACROSS LOWER MICHIGAN OVERNIGHT TOWARDS NW OHIO AND
WILL KEEP A LOW POP IN THE FORECAST FOR OVERNIGHT. SEVERE WEATHER IS
NOT EXPECTED LATER TONIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
SHOWERS AND THUNDERSTORMS SHOULD GENERALLY BE LOCATED NORTH OF THE
AREA TO START THE DAY ON TUESDAY. INSTABILITY AND DEEP MOISTURE AXIS
WILL CONTINUE TO INCREASE OVER THE AREA WITH A WEST SOUTHWESTERLY
FLOW AHEAD OF THE APPROACHING FRONT. TEMPERATURES WILL APPROACH 90
DEGREES IN NW OHIO WITH DEWPOINTS CLIMBING INTO THE LOW 70S. THIS
WILL PUSH HEAT INDEX VALUES TO AROUND 95 DEGREES WHICH WILL BE NEAR
THE HOTTEST CONDITIONS EXPERIENCED ALL SUMMER TOWARDS THE I-75
CORRIDOR. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO FILL IN AS THE
FRONT SINKS SOUTH TOWARDS NW OHIO DURING THE AFTERNOON. THE FRONT IS
EXPECTED TO BE FAIRLY SLOW MOVING DURING THE AFTERNOON...DEPENDING
ON THE EVOLUTION OF THE CONVECTION. A SERIES OF SHORTWAVES WILL
ROUND THE RIDGE AND PUSH THE FRONTAL BOUNDARY SOUTHWARD OVERNIGHT.
NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED ON LAKE ERIE TUESDAY
NIGHT...SINKING SOUTH ACROSS THE EASTERN CWA OVERNIGHT. GIVEN THE
VERY MOIST AIRMASS AND MOVEMENT ALONG THE FRONT...VERY HEAVY RAIN
WILL BE POSSIBLE WITH THUNDERSTORMS ON TUESDAY NIGHT AND WILL HAVE
TO CONSIDER THE POTENTIAL FOR LOCALIZED FLOODING.
THE FRONT STILL LOOKS TO PUSH SOUTH ACROSS THE AREA ON WEDNESDAY
MORNING SO WILL CONTINUE WITH SHOWERS AND THUNDERSTORMS ENDING
DURING THE MORNING. THE TIMING OF THE CONVECTION DURING THE TUESDAY
NIGHT INTO WEDNESDAY MORNING IS NOT REAL FAVORABLE FOR SEVERE
THUNDERSTORMS. LOWERED HIGHS ON WEDNESDAY SEVERAL MORE DEGREES WITH
BACK INTO THE MID 70S TO LOWER 80S. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT ON WEDNESDAY NIGHT AND THURSDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
I THINK THE KEY FOR THE LONG TERM PORTION OF THE FORECAST IS THE
PROGRESSION OF THE TROUGH EASTWARD FROM THE ROCKIES. MOST OF THE
MORE RELIABLE GUIDANCE SHOWS THE TROUGH APPROACHING BY SUNDAY BUT
THERE IS STILL A LOT OF UNCERTAINTY.
IN THE MEAN TIME...THE STALLED SURFACE FRONT WILL RETURN NORTH AS A
WARM FRONT ON FRIDAY. NOT SURE HOW MUCH COVERAGE OF SHOWERS AND
THUNDERSTORMS THERE MIGHT BE...THE GFS SEEMS TYPICALLY TOO STRONG
AND TOO FAR NORTH WITH THE SURFACE WAVE. AND SOME OF THE OTHER
MODELS HAVE THE CONVECTIVE FEEDBACK LOOK. WILL HAVE A CHANCE OF
SHOWERS AND STORMS FRIDAY INTO SATURDAY. IT WOULD SEEM THAT THE WARM
SECTOR SHOULD MAKE PROGRESS NORTHWARD INTO THE AREA BY THE WEEKEND
BUT WILL NOT GO ALL OUT ON TEMPS YET FOR SATURDAY UNTIL A LITTLE
MORE CONFIDENT OF THE TIMING. THE FORECAST WILL HAVE HIGHS IN THE
LOWER AND MID 80S ON SATURDAY BUT TEMPS COULD TAKE A RUN TOWARD 90F.
AS MENTIONED BEFORE...THE THUNDERSTORMS SHOULD INCREASE ON SUNDAY
BUT WILL ONLY GO FOR A 50 PERCENT CHANCE FOR NOW...NOT YET
COMFORTABLE FORECASTING "LIKELY" GIVEN THE UNCERTAINTY.
THE FRONT MAY BE THROUGH THE AREA ON MONDAY LABOR DAY AND PERHAPS
THE SHOWER THREAT WILL MOVE EAST WITH SOMEWHAT COOLER TEMPS.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A RELATIVELY SMALL CUMULUS FIELD WAS SPREADING OUT ACROSS NORTH
CENTRAL OHIO BUT THE CUMULUS SHOULD SCATTER OUT DURING THE MID TO
LATE AFTERNOON AND EVENTUALLY EVAPORATE THIS EVENING. HIGH CLOUDS
WILL SPREAD ACROSS THE AREA FROM THE THUNDERSTORMS IN MICHIGAN AND
SCATTERED TO BROKEN ALTOCUMULUS WILL PROBABLY DEVELOP IN THE EARLY
MORNING HOURS ON TUESDAY. THERE IS AN OUTSIDE CHANCE THAT SHOWERS
OR THUNDERSTORMS COULD SNEAK INTO NORTHWEST OHIO TUESDAY MORNING
BUT WILL NOT INCLUDE IT IN THE TAF FORECASTS AT THIS TIME.
OUTLOOK...NON VFR POSSIBLE TUESDAY EVENING INTO WEDNESDAY MORNING
IN SHOWERS AND THUNDERSTORMS.
&&
.MARINE...
THE SOUTHEAST FLOW ON THE LAKE WILL BE LOCALLY ONSHORE EARLY THIS
EVENING OTHERWISE IT WILL CONTINUE TO VEER MORE FROM THE SOUTH AND
THEN SOUTHWEST AHEAD OF THE NEXT COLD FRONT. THE TIMING ON THE FRONT
STILL SEEMS TO BE LATE TUESDAY NIGHT OR EARLY WEDNESDAY. THE FLOW
SHOULD BECOME NORTHERLY SOON AFTER THE FRONTAL PASSAGE. THE
GRADIENT AHEAD OF THE FRONT AND BEHIND THE FRONT IS LIGHT TO
MODERATE BUT EVEN A MODERATE NORTH WIND MAY APPROACH SMALL CRAFT
ADVISORY CONDITIONS LATER WEDNESDAY INTO WEDNESDAY NIGHT. THE HIGH
PRESSURE SYSTEM IS EXPECTED TO CROSS EASTERN CANADA SO THE FLOW
SHOULD VEER MORE EASTERLY BY THURSDAY NIGHT AND SOUTHEAST AND SOUTH
AGAIN BY THE WEEKEND.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...KEC
LONG TERM...KOSARIK
AVIATION...KOSARIK
MARINE...KOSARIK
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
333 PM CDT MON AUG 25 2014
.DISCUSSION...
IT IS A QUIET AND WARM DAY ACROSS THE REGION AS WE AWAIT OUR NEXT
WEATHER SYSTEMS. THE UPPER LEVEL RIDGE THAT HAS BEEN DOMINATING OUR
WEATHER PATTERN THE LAST FEW DAYS HAS MOVED TO OUR NORTHEAST AND WILL
REMAIN CENTERED TO OUR NORTHEAST AS A TUTT LOW IN THE NORTHERN
GULF OF MEXICO MOVES WEST TOWARDS THE TEXAS COAST. THIS FEATURE IS
SCHEDULED BY MOST OF THE MODELS TO APPROACH THE TEXAS COAST
TUESDAY AFTERNOON BUT THE RAP IS INDICATING A MUCH SLOWER MOVEMENT
OF THE TUTT. IN ADDITION...THE TRACK OF THE TUTT APPEARS TO BE
SLIGHTLY FURTHER SOUTH THAN PREVIOUS MODEL RUNS. DESPITE
THIS...RICH TROPICAL MOISTURE WILL STILL MOVE WEST AND NORTHWEST
INTO THE REGION STARTING TUESDAY AND THE UPPER LEVEL RIDGE WILL
WEAKEN SOME OVER THE REGION. THIS WILL ALLOW ISOLATED TO SCATTERED
CONVECTION TO DEVELOP ACROSS THE REGION TOMORROW AFTERNOON.
COVERAGE IS NOT EXPECTED TO BE VERY HIGH SO KEPT RAIN CHANCES AT
20 PERCENT ACROSS THE EAST AND SOUTHEAST WITH JUST AN ISOLATED
MENTION ELSEWHERE. GUSTY WINDS...LIGHTNING AND BRIEF HEAVY RAIN
WILL BE POSSIBLE WITH ANY THUNDERSTORMS.
ON WEDNESDAY...WE WILL REMAIN IN A TRANSITION PERIOD AS AN UPPER
LEVEL TROUGH MOVES ACROSS THE WESTERN CONUS. THIS TROUGH WILL HELP
TO FURTHER PUSH THE RIDGE TO THE EAST. ISOLATED TO SCATTERED
CONVECTION WILL BE POSSIBLE ON WEDNESDAY AS RICH ATMOSPHERIC
MOISTURE REMAINS IN PLACE. ON THURSDAY THE UPPER LEVEL TROUGH
MOVES INTO THE PLAINS. PREVIOUS MODEL RUNS WERE IN DECENT
AGREEMENT ON THE SPEED OF THE TROUGH BUT THE LATEST RUNS HAVE
AGAIN STARTED TO DIVERGE FROM EACH OTHER. AS THE TROUGH APPROACHES
FROM THE WEST ON THURSDAY...ISOLATED TO SCATTERED CONVECTION WILL
AGAIN OCCUR IN THE AFTERNOON AND EVENING HOURS WITH BETTER
COVERAGE LIKELY IN THE SOUTHEAST WHERE THE MOISTURE WILL BE
HIGHER...AND IN THE NORTHWEST CLOSER TO THE APPROACHING TROUGH.
OUR BEST RAIN CHANCES WILL BE FRIDAY AND/OR SATURDAY DEPENDING ON
THE SPEED OF THE TROUGH. THE GFS IS THE FASTEST OF THE EXTENDED
MODELS WITH THE ECMWF THE SLOWEST OF THE MODELS. BECAUSE OF THE
DISCREPANCIES...HAVE LINGERED POPS INTO SUNDAY AND ENDED THEM
FROM WEST TO EAST THROUGH THE DAY. IF THE GFS IS REALIZED AND THE
TROUGH IS OFF TO OUR NORTHEAST BY SATURDAY NIGHT...THE RAIN
CHANCES WILL END EARLIER. BENEFICIAL RAIN IS POSSIBLE WITH THIS
SYSTEM DEPENDING ON THE SPEED OF THE UPPER LEVEL TROUGH BUT SOME
LOCATIONS WILL BENEFIT FROM THE RAIN MORE THAN OTHERS.
WITH THE PATTERN CHANGE THIS WEEK...TEMPERATURES THROUGH MIDWEEK
WILL BE SLIGHTLY ABOVE NORMAL BUT BELOW 100 DEGREES. FOR THE
LATTER HALF OF THE WEEK...EXPECT NEAR OR SLIGHTLY BELOW NORMAL
TEMPERATURES.
82/JLD
&&
.AVIATION...
/ISSUED 1257 PM CDT MON AUG 25 2014/
FOR THE 18Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID
FORECAST PERIOD. THUNDERSTORM CHANCES AROUND AREA TAF SITES
TOMORROW AFTERNOON IS THE PRIMARY AVIATION WEATHER CONCERN.
IN THE SHORT TERM...LIGHT SOUTHWESTERLY WINDS ARE EXPECTED TO
BECOME SOUTHEASTERLY BY 20Z. FORECAST SOUNDINGS AND MORNING
AIRCRAFT RAOBS INDICATED THAT HEATING TODAY WAS UNLIKELY TO BREAK
THE CAP IN PLACE OVER THE REGION. THEREFORE DRY CONDITIONS ARE
EXPECTED OVER THE NEXT 18 HOURS. BY TOMORROW AFTERNOON...18-24
HOURS OF SOUTHEASTERLY WINDS SHOULD BRING DEEPER MOISTURE INTO THE
REGION WHICH WILL ALLOW FOR ISOLATED TO SCATTERED THUNDERSTORMS TO
DEVELOP ACROSS THE REGION DURING THE PEAK HEATING HOURS OF THE DAY
TOMORROW AFTERNOON. WENT AHEAD WITH A MENTION OF VCTS AT THE END
OF THE DFW TAF TO ACCOUNT FOR THIS POSSIBILITY. CONFIDENCE IS HIGH
THAT A STORM WILL DIRECTLY IMPACT A TAF SITE...BUT MOST FORECAST
SOUNDINGS INDICATED LITTLE CAP IN PLACE OVER THE REGION BY 21Z
TOMORROW.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 79 98 77 98 77 / 5 10 10 10 10
WACO, TX 75 98 74 98 74 / 5 10 10 10 10
PARIS, TX 73 95 72 95 71 / 5 20 20 10 10
DENTON, TX 76 97 74 97 73 / 5 10 10 10 10
MCKINNEY, TX 75 96 74 96 72 / 5 10 10 10 10
DALLAS, TX 80 98 78 98 77 / 5 10 10 10 10
TERRELL, TX 77 98 76 97 74 / 5 20 20 10 10
CORSICANA, TX 77 98 76 97 74 / 5 20 20 20 20
TEMPLE, TX 74 99 74 98 73 / 5 10 10 20 20
MINERAL WELLS, TX 74 98 73 98 74 / 10 10 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
69/82
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1257 PM CDT MON AUG 25 2014
.AVIATION...
FOR THE 18Z TAFS...VFR CONDITIONS ARE EXPECTED THROUGH THE VALID
FORECAST PERIOD. THUNDERSTORM CHANCES AROUND AREA TAF SITES
TOMORROW AFTERNOON IS THE PRIMARY AVIATION WEATHER CONCERN.
IN THE SHORT TERM...LIGHT SOUTHWESTERLY WINDS ARE EXPECTED TO
BECOME SOUTHEASTERLY BY 20Z. FORECAST SOUNDINGS AND MORNING
AIRCRAFT RAOBS INDICATED THAT HEATING TODAY WAS UNLIKELY TO BREAK
THE CAP IN PLACE OVER THE REGION. THEREFORE DRY CONDITIONS ARE
EXPECTED OVER THE NEXT 18 HOURS. BY TOMORROW AFTERNOON...18-24
HOURS OF SOUTHEASTERLY WINDS SHOULD BRING DEEPER MOISTURE INTO THE
REGION WHICH WILL ALLOW FOR ISOLATED TO SCATTERED THUNDERSTORMS TO
DEVELOP ACROSS THE REGION DURING THE PEAK HEATING HOURS OF THE DAY
TOMORROW AFTERNOON. WENT AHEAD WITH A MENTION OF VCTS AT THE END
OF THE DFW TAF TO ACCOUNT FOR THIS POSSIBILITY. CONFIDENCE IS HIGH
THAT A STORM WILL DIRECTLY IMPACT A TAF SITE...BUT MOST FORECAST
SOUNDINGS INDICATED LITTLE CAP IN PLACE OVER THE REGION BY 21Z
TOMORROW.
CAVANAUGH
&&
.UPDATE...
THE UPPER LEVEL RIDGE WILL CONTINUE TO CONTROL THE WEATHER
RESULTING IN A HOT DAY ACROSS THE REGION UNDER CLEAR OR MOSTLY
CLEAR SKIES WITH LIGHT WINDS. FORECAST MODELS INDICATE THE
PRECIPITATION THAT CONTINUES IN THE TEXAS PANHANDLE IS OCCURRING
WITHIN A SHEAR AXIS THAT WILL CONTINUE TO SLIDE EAST-NORTHEAST
TODAY. THE HRRR DEVELOPS ISOLATED CONVECTION IN OUR FAR
NORTHWESTERN COUNTIES THIS AFTERNOON...NEAR THIS SHEAR AXIS BUT AS
OF NOW IT IS THE ONLY MODEL DEVELOPING CONVECTION IN THE AREA.
FORECAST MODEL SOUNDINGS IN THAT AREA INDICATE A DRY ATMOSPHERE IN
PLACE THROUGH THE REGION AND AM NOT INCLINED TO ADD POPS AT THIS
TIME BUT WILL INCLUDE SILENT 10 POPS AND WATCH TRENDS THROUGH THE
AFTERNOON HOURS. OTHERWISE...THE FORECAST WAS ON TRACK AND NO
SIGNIFICANT CHANGES WERE NEEDED FOR THE UPDATE.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 347 AM CDT MON AUG 25 2014/
THE UPPER LEVEL HIGH THAT BROUGHT US OUR LATEST STRETCH OF HOT AND
DRY WEATHER WILL BEGIN TO WEAKEN AND BACK OFF TO THE NORTHEAST
TODAY AND TOMORROW. SURFACE WINDS WILL BE FAIRLY LIGHT TODAY WHICH
MEANS HIGH TEMPS WILL BE A LITTLE WARMER THAN YESTERDAY. ALSO LOW
TEMPS IN NON-URBAN AREAS WILL COOL OFF A LITTLE MORE TONIGHT
COMPLIMENTS OF THE LIGHT WINDS AND CLEAR SKIES.
THE LATEST WATER VAPOR LOOP SHOWS THE WEAK TUTT LOW THAT WE HAVE
BEEN TRACKING FOR THE LAST FEW DAYS HAS MOVED WEST INTO THE
CENTRAL GULF. MEANWHILE A NON-TROPICAL SURFACE LOW CENTER HAS
DEVELOPED NEAR THE MISSISSIPPI RIVER DELTA ALONG AN OLD FRONTAL
BOUNDARY THAT HAS PUSHED INTO THE NORTHEAST GULF OF MEXICO. THE
TUTT AND SURFACE LOW WILL CONTINUE ON A WESTERLY TRACK...WITH THE
UPPER TUTT AXIS CROSSING OUR CWA TUESDAY AND CAUSING PRECIPITABLE
WATER VALUES TO SURGE TO NEAR 2 INCHES. THE BETTER CHANCES OF RAIN
WILL BE OVER THE EASTERN AND SOUTHEASTERN ZONES TUESDAY AFTERNOON
AND EVENING WHERE LIFT/MOISTURE ARE GREATER. HOWEVER WILL MENTION
ISOLATED SHOWERS/STORMS IN THE FORECAST ALONG AND WEST OF THE I-35
CORRIDOR AS THERE IS SOME SPATTERING OF QPF FROM SEVERAL MODELS
THERE AS WELL. LOW LEVEL WINDS WILL BECOME EASTERLY DURING THE DAY
TUESDAY AND WE WILL SEE THE BEGINNING OF A SLIGHT COOLING TREND
IN HIGH TEMPS AS LOW LEVEL THICKNESSES DECREASE FROM EAST TO WEST.
THE SURFACE LOW WILL HANG OUT IN THE WESTERN GULF INTO THURSDAY...
AND WHILE TROPICAL DEVELOPMENT OF THIS FEATURE IS NOT LIKELY...IT
WILL TEND TO CONSOLIDATE THE BETTER MOISTURE/CONVECTION OVER THE
WESTERN GULF AND SOUTH TEXAS. NORTH TEXAS WILL SEE DRY ADVECTION
DUE TO PERSISTENT EASTERLY FETCH IN THE LOW LEVELS AROUND THIS
CYCLONE...AND THUS HAVE LOWERED POPS TO 10 PERCENT. WILL RETAIN A
MENTION OF AFTERNOON/EVENING ISOLATED CONVECTION IN THE WORDED
FORECAST AS MOISTURE AND INSTABILITY STILL SHOULD BE SUFFICIENT
FOR SUCH ON WEDNESDAY. MOISTURE DIMINISHES EVEN MORE INTO
THURSDAY...AND THUS WILL SHOW A DRY FORECAST EXCEPT FOR THE
SOUTHEAST ZONES. MOST OF THE RAIN ACTIVITY WILL REMAIN TO OUR
SOUTH AND EAST WHERE PRECIPITABLE WATERS STAY ABOVE 2 INCHES WITH
THE GULF LOW PRESSURE SYSTEM.
FORTUNATELY...AFTER SEVERAL DAYS OF MODEL DISAGREEMENT...GUIDANCE
HAS COME INTO EXCELLENT AGREEMENT REGARDING THE TRACK AND SPEED OF
A LONGWAVE TROUGH THAT MOVES EAST ACROSS THE CONUS. AS THIS SYSTEM
APPROACHES THE REGION THURSDAY AND FRIDAY...IT WILL DRAW THE RICH
GULF MOISTURE NORTHWESTWARD INTO THE REGION. RAIN CHANCES WILL
INCREASE FRIDAY AND INTO SATURDAY AS UPPER LEVEL FORCING FROM THE
TROUGH INTERACTS WITH THIS HIGH MOISTURE AND INSTABILITY. LIFT
FROM THE UPPER TROUGH LOOKS FAIRLY STRONG FOR THE TIME OF THE
YEAR...AND SHEAR MAY BE MARGINALLY SUFFICIENT FOR MULTICELL
CONVECTIVE MODES WITH A THREAT FOR SOME SEVERE STORMS. HIGH
PRECIPITABLE WATER AND INSTABILITY WILL CERTAINLY SUPPORT A
LOCALLY HEAVY RAIN THREAT. HAVE BUMPED UP POPS TO 30 PERCENT FOR
MOST OF THE AREA FRIDAY NIGHT AND SATURDAY...AND THESE POPS WILL
PROBABLY BE RAISED FURTHER AS CONFIDENCE IN THE TIMING OF THE
UPPER TROUGH INCREASES. RAIN CHANCES SHOULD DIMINISH SUNDAY FROM
WEST TO EAST WITH THE PASSAGE OF THE UPPER TROUGH AXIS.
TEMPERATURES WILL COOL INTO THE LOW TO MID 90S FRIDAY AND SATURDAY
DUE TO THE INCREASED CLOUDS AND MOISTURE. TEMPS REBOUND ONLY
SLIGHTLY SUNDAY AND MONDAY AS GEOPOTENTIAL HEIGHTS REMAIN
DEPRESSED IN THE WAKE OF THE UPPER TROUGH.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 101 78 99 78 98 / 5 5 10 10 10
WACO, TX 101 75 99 74 98 / 5 5 10 20 10
PARIS, TX 97 75 95 73 95 / 5 5 20 20 10
DENTON, TX 100 75 98 74 97 / 5 5 10 10 10
MCKINNEY, TX 99 75 97 74 96 / 5 5 10 10 10
DALLAS, TX 100 80 99 79 98 / 5 5 10 10 10
TERRELL, TX 100 77 98 75 97 / 5 5 20 20 10
CORSICANA, TX 100 76 98 75 97 / 5 5 20 20 20
TEMPLE, TX 100 74 99 73 98 / 5 5 10 20 20
MINERAL WELLS, TX 102 74 100 73 98 / 10 10 5 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1148 AM CDT MON AUG 25 2014
.UPDATE...
THE UPPER LEVEL RIDGE WILL CONTINUE TO CONTROL THE WEATHER
RESULTING IN A HOT DAY ACROSS THE REGION UNDER CLEAR OR MOSTLY
CLEAR SKIES WITH LIGHT WINDS. FORECAST MODELS INDICATE THE
PRECIPITATION THAT CONTINUES IN THE TEXAS PANHANDLE IS OCCURRING
WITHIN A SHEAR AXIS THAT WILL CONTINUE TO SLIDE EAST-NORTHEAST
TODAY. THE HRRR DEVELOPS ISOLATED CONVECTION IN OUR FAR
NORTHWESTERN COUNTIES THIS AFTERNOON...NEAR THIS SHEAR AXIS BUT AS
OF NOW IT IS THE ONLY MODEL DEVELOPING CONVECTION IN THE AREA.
FORECAST MODEL SOUNDINGS IN THAT AREA INDICATE A DRY ATMOSPHERE IN
PLACE THROUGH THE REGION AND AM NOT INCLINED TO ADD POPS AT THIS
TIME BUT WILL INCLUDE SILENT 10 POPS AND WATCH TRENDS THROUGH THE
AFTERNOON HOURS. OTHERWISE...THE FORECAST WAS ON TRACK AND NO
SIGNIFICANT CHANGES WERE NEEDED FOR THE UPDATE.
82/JLD
&&
.AVIATION...
/ISSUED 638 AM CDT MON AUG 25 2014/
CONCERNS...NONE.
SURFACE HIGH PRESSURE TO THE EAST-NORTHEAST WILL BE LOOSENING ITS
GRIP ON THE REGION WHILE A SURFACE TROUGH REMAINS WILL REMAIN
ACROSS THE PANHANDLE AND WEST TEXAS REGION. THIS WILL CAUSE WINDS
TO BACK TO THE SOUTHEAST LATE THIS AFTERNOON AND REMAIN SO OVERNIGHT.
COULD SEE A SOUTHWEST COMPONENT FOR A FEW HOURS THIS MORNING.
ALL TERMINALS WILL BE VFR WITH SOUTHERLY WINDS LESS THAN 10 KNOTS
TODAY AND SOUTHEASTERLY WINDS LESS THAN 8 KNOTS TONIGHT. 75
&&
.PREV DISCUSSION... /ISSUED 347 AM CDT MON AUG 25 2014/
THE UPPER LEVEL HIGH THAT BROUGHT US OUR LATEST STRETCH OF HOT AND
DRY WEATHER WILL BEGIN TO WEAKEN AND BACK OFF TO THE NORTHEAST
TODAY AND TOMORROW. SURFACE WINDS WILL BE FAIRLY LIGHT TODAY WHICH
MEANS HIGH TEMPS WILL BE A LITTLE WARMER THAN YESTERDAY. ALSO LOW
TEMPS IN NON-URBAN AREAS WILL COOL OFF A LITTLE MORE TONIGHT
COMPLIMENTS OF THE LIGHT WINDS AND CLEAR SKIES.
THE LATEST WATER VAPOR LOOP SHOWS THE WEAK TUTT LOW THAT WE HAVE
BEEN TRACKING FOR THE LAST FEW DAYS HAS MOVED WEST INTO THE
CENTRAL GULF. MEANWHILE A NON-TROPICAL SURFACE LOW CENTER HAS
DEVELOPED NEAR THE MISSISSIPPI RIVER DELTA ALONG AN OLD FRONTAL
BOUNDARY THAT HAS PUSHED INTO THE NORTHEAST GULF OF MEXICO. THE
TUTT AND SURFACE LOW WILL CONTINUE ON A WESTERLY TRACK...WITH THE
UPPER TUTT AXIS CROSSING OUR CWA TUESDAY AND CAUSING PRECIPITABLE
WATER VALUES TO SURGE TO NEAR 2 INCHES. THE BETTER CHANCES OF RAIN
WILL BE OVER THE EASTERN AND SOUTHEASTERN ZONES TUESDAY AFTERNOON
AND EVENING WHERE LIFT/MOISTURE ARE GREATER. HOWEVER WILL MENTION
ISOLATED SHOWERS/STORMS IN THE FORECAST ALONG AND WEST OF THE I-35
CORRIDOR AS THERE IS SOME SPATTERING OF QPF FROM SEVERAL MODELS
THERE AS WELL. LOW LEVEL WINDS WILL BECOME EASTERLY DURING THE DAY
TUESDAY AND WE WILL SEE THE BEGINNING OF A SLIGHT COOLING TREND
IN HIGH TEMPS AS LOW LEVEL THICKNESSES DECREASE FROM EAST TO WEST.
THE SURFACE LOW WILL HANG OUT IN THE WESTERN GULF INTO THURSDAY...
AND WHILE TROPICAL DEVELOPMENT OF THIS FEATURE IS NOT LIKELY...IT
WILL TEND TO CONSOLIDATE THE BETTER MOISTURE/CONVECTION OVER THE
WESTERN GULF AND SOUTH TEXAS. NORTH TEXAS WILL SEE DRY ADVECTION
DUE TO PERSISTENT EASTERLY FETCH IN THE LOW LEVELS AROUND THIS
CYCLONE...AND THUS HAVE LOWERED POPS TO 10 PERCENT. WILL RETAIN A
MENTION OF AFTERNOON/EVENING ISOLATED CONVECTION IN THE WORDED
FORECAST AS MOISTURE AND INSTABILITY STILL SHOULD BE SUFFICIENT
FOR SUCH ON WEDNESDAY. MOISTURE DIMINISHES EVEN MORE INTO
THURSDAY...AND THUS WILL SHOW A DRY FORECAST EXCEPT FOR THE
SOUTHEAST ZONES. MOST OF THE RAIN ACTIVITY WILL REMAIN TO OUR
SOUTH AND EAST WHERE PRECIPITABLE WATERS STAY ABOVE 2 INCHES WITH
THE GULF LOW PRESSURE SYSTEM.
FORTUNATELY...AFTER SEVERAL DAYS OF MODEL DISAGREEMENT...GUIDANCE
HAS COME INTO EXCELLENT AGREEMENT REGARDING THE TRACK AND SPEED OF
A LONGWAVE TROUGH THAT MOVES EAST ACROSS THE CONUS. AS THIS SYSTEM
APPROACHES THE REGION THURSDAY AND FRIDAY...IT WILL DRAW THE RICH
GULF MOISTURE NORTHWESTWARD INTO THE REGION. RAIN CHANCES WILL
INCREASE FRIDAY AND INTO SATURDAY AS UPPER LEVEL FORCING FROM THE
TROUGH INTERACTS WITH THIS HIGH MOISTURE AND INSTABILITY. LIFT
FROM THE UPPER TROUGH LOOKS FAIRLY STRONG FOR THE TIME OF THE
YEAR...AND SHEAR MAY BE MARGINALLY SUFFICIENT FOR MULTICELL
CONVECTIVE MODES WITH A THREAT FOR SOME SEVERE STORMS. HIGH
PRECIPITABLE WATER AND INSTABILITY WILL CERTAINLY SUPPORT A
LOCALLY HEAVY RAIN THREAT. HAVE BUMPED UP POPS TO 30 PERCENT FOR
MOST OF THE AREA FRIDAY NIGHT AND SATURDAY...AND THESE POPS WILL
PROBABLY BE RAISED FURTHER AS CONFIDENCE IN THE TIMING OF THE
UPPER TROUGH INCREASES. RAIN CHANCES SHOULD DIMINISH SUNDAY FROM
WEST TO EAST WITH THE PASSAGE OF THE UPPER TROUGH AXIS.
TEMPERATURES WILL COOL INTO THE LOW TO MID 90S FRIDAY AND SATURDAY
DUE TO THE INCREASED CLOUDS AND MOISTURE. TEMPS REBOUND ONLY
SLIGHTLY SUNDAY AND MONDAY AS GEOPOTENTIAL HEIGHTS REMAIN
DEPRESSED IN THE WAKE OF THE UPPER TROUGH.
TR.92
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 101 78 99 78 98 / 5 5 10 10 10
WACO, TX 101 75 99 74 98 / 5 5 10 20 10
PARIS, TX 97 75 95 73 95 / 5 5 20 20 10
DENTON, TX 100 75 98 74 97 / 5 5 10 10 10
MCKINNEY, TX 99 75 97 74 96 / 5 5 10 10 10
DALLAS, TX 100 80 99 79 98 / 5 5 10 10 10
TERRELL, TX 100 77 98 75 97 / 5 5 20 20 10
CORSICANA, TX 100 76 98 75 97 / 5 5 20 20 20
TEMPLE, TX 100 74 99 73 98 / 5 5 10 20 20
MINERAL WELLS, TX 102 74 100 73 98 / 10 10 5 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
69/82
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
254 PM CDT MON AUG 25 2014
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 254 PM CDT MON AUG 25 2014
MAIN FORECAST CONCERN IS WITH THE RAIN CHANCES THROUGH THE PERIOD.
SURFACE ANALYSIS THIS AFTERNOON SUGGESTS THE COLD FRONT IS MAKING
SLOW EASTWARD PROGRESS THROUGH THE WESTERN SECTIONS OF THE
FORECAST AREA. DEW POINTS REMAIN IN THE 70S AHEAD OF THE FRONT BUT
THEN DROP OFF INTO THE 50S ACROSS CENTRAL MINNESOTA. LOCAL AND
REGIONAL RADARS SHOW THE LINE OF STORMS THAT MOVED THROUGH
OVERNIGHT EXTEND FROM SOUTHEAST WISCONSIN INTO EASTERN IOWA AND
ARE STARTING TO INTENSIFY AGAIN.
THE EXPECTATION THROUGH THE REST OF THE AFTERNOON INTO THE EVENING
IS THAT THE ONGOING ACTIVITY WILL CONTINUE TO MOVE AWAY FROM THE
AREA AS THE FRONT PROGRESSES THROUGH THE FORECAST AREA. SOME
ADDITIONAL ACTIVITY FORMING ON THE WESTERN PART OF THE FRONT OVER
THE MISSOURI RIVER VALLEY. THE 25.17Z HRRR SUGGESTS THIS WILL
TRACK INTO CENTRAL IOWA BEFORE DIMINISHING. HOWEVER...CONFIDENCE
IN THIS MODEL OUTPUT IS NOT THAT HIGH. OUTPUT FROM THE 25.15Z
HOP-WRF DOES SUGGEST THIS MAY SURVIVE AND COME ACROSS NORTHEAST
IOWA THIS EVENING AND WILL SHOW SOME SMALL RAIN CHANCES FOR THIS.
ADDITIONAL CONVECTION SHOULD FORM OVERNIGHT ALONG THE COLD FRONT
AS A SHORT WAVE TROUGH COMES OUT OF THE CENTRAL ROCKIES. THE
MOISTURE TRANSPORT INTO THE FRONT DOES NOT LOOK TO BE ALL THAT
STRONG TONIGHT AND AS CANADIAN HIGH PRESSURE BUILDS IN FROM THE
NORTH...THE BULK OF THE RAIN TONIGHT SHOULD REMAIN OVER CENTRAL
AND SOUTHERN IOWA.
THE HIGH WILL GRADUALLY MOVE EAST-SOUTHEAST ACROSS THE UPPER
MIDWEST AND BE OVER THE U.P. OF MICHIGAN BY WEDNESDAY NIGHT. THIS
IS EXPECTED TO KEEP THE FRONT FAR ENOUGH SOUTH THAT MOST OF THE
CONVECTION ALONG IT FROM TUESDAY THROUGH WEDNESDAY SHOULD STAY TO
THE SOUTH. CANNOT RULE OUT THE SOUTHERN PARTS OF THE FORECAST AREA
GETTING CAUGHT ON THE NORTH EDGE OF THE COMPLEXES THAT FORM ALONG
THE FRONT AND WILL SHOW SOME 20 TO 40 PERCENT RAIN CHANCES FOR
THIS SCENARIO.
BY WEDNESDAY NIGHT THE HIGH WILL START TO MOVE FARTHER OFF TO THE
EAST ALLOWING DEEPER MOISTURE TO START RETURNING TO THE AREA. THIS
MOISTURE RETURN SHOULD OCCUR AHEAD OF STRONGER SHORT WAVE TROUGH
EJECTING NORTHEAST OUT OF THE CENTRAL ROCKIES. THIS WAVE SHOULD
BRING AT LEAST SOME WEAK PV ADVECTION IN THE 500-300 MB LAYER INTO
THE AREA ALONG WITH 1 TO 3 UBAR/S OF UP GLIDE ON THE 310K
ISENTROPIC SURFACE. SHOULD SEE ACTIVITY DEVELOP TO THE
WEST/SOUTHWEST OF THE AREA WEDNESDAY EVENING AND THEN MOVE IN
DURING THE OVERNIGHT HOURS.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 254 PM CDT MON AUG 25 2014
THE SHORT WAVE TROUGH THAT COMES OUT WEDNESDAY NIGHT WILL TRACK
ACROSS THE UPPER MIDWEST THURSDAY AND SHOULD BE THE FIRST OF
SEVERAL WAVES AS THE MEAN LONG WAVE TROUGH SLOWLY MOVES EAST AS IT
BUMPS INTO THE RIDGING OVER THE EASTERN CONUS. DIFFERENCES BETWEEN
THE 25.12Z ECMWF AND GFS ON HOW FAST THE LONG WAVE TROUGH WILL
MOVE EAST WITH THE ECMWF BEING SLOWER THAN THE GFS. ALSO
DIFFERENCES ON HOW MUCH RIDGING WILL OCCUR BEHIND THIS LONG WAVE
TROUGH AHEAD OF THE NEXT SYSTEM MOVING ONTO THE PACIFIC NORTHWEST
COAST. WITH SUCH DIFFERENCES BETWEEN THE MODELS PLAN TO STAY WITH
THE MODEL CONSENSUS GRIDS AND SHOW RAIN CHANCES THROUGH MUCH OF
THE PERIOD WITH THE HIGHEST CHANCES THURSDAY AND THURSDAY NIGHT AS
THE FIRST SHORT WAVE TROUGH COMES ACROSS THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1258 PM CDT MON AUG 25 2014
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD. A COLD
FRONT WILL PUSH SOUTH AND EAST OF THE TAF SITES LATE THIS
AFTERNOON INTO THIS EVENING. THE FRONT LOOKS TO STALL OVER
PORTIONS OF CENTRAL OR NORTHERN IOWA INTO CENTRAL ILLINOIS AND
WILL BE THE FOCUS FOR SHOWERS AND STORMS. THIS ACTIVITY WILL
REMAIN SOUTH OF THE TAF SITES THE NEXT FEW DAYS AS HIGH PRESSURE
BUILDS IN. PLAN ON MID TO HIGH CLOUDS PUSHING NORTH OF THE SHOWER
AND STORM ACTIVITY THIS EVENING INTO THE OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...04
LONG TERM...04
AVIATION...WETENKAMP
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 242 PM CDT MON AUG 25 2014
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN OCCLUDED
LOW PRESSURE OVER LAKE WINNIPEG AND A COLD FRONT SLICING ACROSS
WESTERN LAKE SUPERIOR AND WISCONSIN FROM ABOUT HAYWARD TO LA
CROSSE. AHEAD OF THE FRONT...THE ATMOSPHERE HAS BEEN VERY SLOW TO
DESTABILIZE AS TEMPERATURES REMAIN IN THE UPPER 70S TO LOWER 80S.
STARTING TO SEE SOME MIDDLE 80S POP UP OVER WEST-CENTRAL WISCONSIN
WHERE ML CAPES ARE RISING TO ABOUT 1200 J/KG. STILL SEVERAL MORE
HOURS OF HEATING TO GO THOUGH ESPECIALLY OVER CENTRAL AND EASTERN
WISCONSIN WHERE CONVECTIVE DEBRIS CONTINUES TO HOVER OVERHEAD.
BECAUSE OF THE SLOWER HEATING SO FAR...HAVE REDUCED THE CHANCES OF
SHOWERS AND THUNDERSTORMS FOR THE REST OF THE AFTERNOON INTO THE
ISOLATED RANGE AFTER 21Z. AS THE FRONT MOVES THROUGH...SHOWER AND
THUNDERSTORM CHANCES ARE THE MAIN FORECAST CONCERN.
TONIGHT...THE COLD FRONT WILL SLOWLY SLIDE SOUTHEAST ACROSS
NORTHEAST AND EAST-CENTRAL WISCONSIN DURING THE EVENING BEFORE
EXITING THE LAKE MICHIGAN SHORELINE AROUND 06-08Z. AHEAD OF THE
FRONT...WILL LEAVE AN ISOLATED MENTION OF SHOWERS AND THUNDERSTORMS
OVER NORTHEAST AND EAST-CENTRAL WISCONSIN UNTIL THE FRONT CLEARS THE
AREA. IF TEMPS CAN RISE INTO MIDDLE 80S AHEAD OF THE FRONT...WHICH
SEEMS REASONABLE...ANY STORMS THAT DEVELOP COULD BECOME STRONG AND
PRODUCE STRONG GUSTY WINDS AND HAIL. HOWEVER...THE MESO MODELS ARE
EXTREMELY BEARISH IN PREDICTING THUNDERSTORMS THIS AFTERNOON. AND
WITH THE SLOW DESTABILIZATION SO FAR TODAY...HAVE LOWERED THE
CHANCES OF STORMS. AS INSTABILITY IS LOST THIS EVENING...INTENSITY
OF ANY STORMS SHOULD WANE QUICKLY BY MID-EVENING. COOLER AND DRIER
AIR WILL GRADUALLY MAKE INROADS ACROSS THE FORECAST AREA BEHIND THE
FRONT...BUT WARM AND MUGGY CONDITIONS SHOULD HANG ON FOR MUCH OF THE
NIGHT ACROSS THE EAST. LOWS RANGING FROM THE MIDDLE 50S NORTH TO
MIDDLE 60S SOUTHEAST.
TUESDAY...THE COLD FRONT WILL CONTINUE TO MOVE SOUTH OVER SOUTHEAST
WISCONSIN AND NORTHERN ILLINOIS WHILE CANADIAN HIGH PRESSURE MOVES
INTO THE NORTHWEST GREAT LAKES. MOST AREAS WILL SEE A GOOD DEAL OF
SUNSHINE...THOUGH CU MAY BE A LITTLE MORE PREVALENT OVER N-C
WISCONSIN WHILE HIGH CLOUDS WILL LIKELY REMAIN OVERHEAD OVER CENTRAL
AND EAST-CENTRAL WISCONSIN. TEMPS AND HUMIDITY LEVELS WILL BE
SIGNIFICANTLY LOWER THAN TODAYS READINGS...AND WILL GO WITH HIGHS IN
THE LOWER 70S NORTH TO THE UPPER 70S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 242 PM CDT MON AUG 25 2014
CONTINUED WITH SAME TRENDS OF FORECAST AS MODELS CONTINUE TO SHOW
A PROGRESSIVE NORTHERN STREAM ALONG THE U.S. AND CANADIAN BORDER
THRU THE END OF THE WEEK. WILL BE DEALING WITH ENERGY MOVING
THROUGH THE NORTHERN STREAM AND WEAK CUT OFF TROF MEANDERING OUT
OF THE WEST...THROUGH THE CENTRAL PLAINS.
TUE NIGHT THROUGH THU...EARLY IN PERIOD...SHORT WAVE TO MOVE OUT
OF NORTHERN PLAINS INTO WESTERN LAKES. AT THE SURFACE DRIER AIR
WITH SURFACE HIGH IN PLACE OVER NORTHERN HALF OF WI WITH FRONT SHOVED
SOUTH INTO NORTHERN IL. HAVE CONTINUED DRY FORECAST FROM PREVIOUS
SHIFT...BUT PAST TWO RUNS OF EC SHOWING LIGHT PCPN BREAKING OUT
OVER THE NORTH ALONG 850 FRONT. LATER SHIFT CAN REVIEW BUT FOR NOW
KEPT DRY. MEANDERING TROF BEGINS TO MOVE INTO CENTRAL PLAINS BY THU.
OLD FRONT TO BEGIN TO MAKE WAY NORTH. MODELS SUGGEST CONVECTIVE
COMPLEX DEVELOPING MN/WESTERN WI AS 850 FLOW INCREASES OVER FRONT.
GFS AND NAM FURTHER NORTH WITH COMPLEX THAN CANADIAN AND EC. SREF
TENDING TO SUPPORT FURTHER SOUTH LOOK. HAVE STAYED CLOSE TO
PREVIOUS FORECAST WITH CHANCE POPS DURING DAY ON THU.
UNSETTLED WEATHER TO THEN PERSIST THROUGH THE END OF THE FORECAST
AS MORE ENERGY MOVES THROUGH CANADA.
TEMPERATURES EXPECTED TO RUN NEAR OR A BIT BELOW NORMAL THROUGH
MUCH OF THE PERIOD.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1143 AM CDT MON AUG 25 2014
SHOWERS AND STORMS HAVE EXITED TO THE SOUTH AND EAST BUT
A COLD FRONT STILL RESIDES OVER WESTERN WISCONSIN AND WILL SLOWLY
MOVE EAST OVER THE COURSE OF THE AFTERNOON. ISOLATED OR SCATTERED
SHOWERS AND STORMS ARE POSSIBLE AHEAD OF THE FRONT OVER NORTHEAST
WISCONSIN ONCE THE ATMOSPHERE DESTABILIZES BY LATER THIS AFTERNOON.
DUE TO UNCERTAINTY IN THE COVERAGE OF THESE STORMS...HAVE LEFT OUT A
MENTION AT THE NORTHEAST WISCONSIN TAF SITES. THE FRONT WILL CLEAR
EAST-CENTRAL WISCONSIN LATE IN THE EVENING OR EARLY
OVERNIGHT...ENDING THE SHOWER AND STORM THREAT. DRIER AIR WILL
BUILD INTO THE REGION LATE TONIGHT AND TUESDAY...WHICH SHOULD LEAD
TO GOOD FLYING CONDITIONS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......TE
AVIATION.......MPC